Water transfer sheet and water transfer method

Abstract

To provide a water pressure transfer method for forming an electric circuit on the surface of an article having a curved surface, and a water pressure transfer sheet used therefor.SOLUTION: The water pressure transfer film has a transfer layer with at least a conductive pattern layer on the surface of the water-soluble film, where the conductive pattern layer comprises a transparent conductive ink, and the conductive ink contains a conductive component selected from the group consisting of polythiophene compounds, polyaniline compounds and graphene. In the water pressure transfer method, the water pressure transfer film is coated with an activator and placed on the surface of water in a water pressure transfer bath, the transferred object is pressed against the water pressure transfer film, and the conductive pattern layer is transferred to the surface of the transferred object by water pressure to obtain a water pressure transfer product.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a hydraulic transfer sheet for transferring and forming an electric circuit pattern in synchronization with a decorative pattern such as a pattern on the surface of an article having a curved surface, and a hydraulic transfer method using the hydraulic transfer sheet.

Background Art

[0002] As a method for forming a circuit pattern using conductive ink, the screen printing method is generally adopted. In recent designs of electronic products, as new needs for various shape designs considering designability, there is an increasing demand for a technique for forming a circuit pattern on a non-planar substrate such as a spherical shape or a curved surface without depending on the shape of a housing or a mounting substrate. However, it is often difficult to apply the conventionally widely adopted screen printing method to this need.

[0003] As a technique for transferring a printed pattern onto the surface of such a non-planar article, a hydraulic transfer sheet having a water-insoluble printed pattern on a water-soluble film (carrier film) is floated on the water surface in a transfer tank. After swelling the water-soluble film of this hydraulic transfer sheet with water, the article (transfer object) is pushed into the water in the transfer tank while contacting the printed pattern of this hydraulic transfer sheet. At this time, a hydraulic transfer method is used to transfer the printed pattern of the hydraulic transfer sheet onto the surface of the article by utilizing the water pressure generated on the surface of the article.

[0004] While water transfer printing is primarily used for decorating curved surfaces, it has been proposed to transfer printed patterns as circuit patterns using conductive ink. For example, Patent Document 1 proposes a circuit pattern formation method using a transfer film for forming circuit patterns, which has a first base film made of a material soluble in a first type of solvent and a conductive pattern made of a conductive adhesive formed on a second base film. The method is characterized by comprising the steps of: floating the transfer film for forming circuit patterns in a first type of solvent; placing a substrate on the transfer film for forming circuit patterns; immersing the transfer film for forming circuit patterns together with the substrate in a first type of solvent to dissolve or peel off the first base film; immersing the transfer film for forming circuit patterns, from which the first base film has been removed, together with the substrate in a second type of solvent to dissolve or peel off the second base film; and performing heat treatment on the conductive pattern remaining on the substrate to harden or solidify the conductive adhesive. This method allows for the formation of circuit patterns even on curved surfaces with large curvatures without causing disconnections.

[0005] Furthermore, Patent Document 2 proposes a method for forming multiple conductive patterns on an object to be transferred by water pressure transfer using a transfer foil made of a curable resin that hardens by electron beam irradiation, ultraviolet irradiation, electromagnetic wave irradiation, charged particle beam irradiation, or heating, comprising a base film having solubility in liquid or swelling due to liquid, a base layer provided on the base film, and a circuit layer provided at least partially on the base layer, wherein the circuit layer has multiple conductive patterns provided at least partially on the base layer, and the base layer is made of a curable resin that hardens by electron beam irradiation, ultraviolet irradiation, electromagnetic wave irradiation, charged particle beam irradiation, or heating. The method of Patent Document 2 makes it possible to form conductive patterns on the surface of an article with high positional accuracy.

[0006] Furthermore, in recent years, there has been a growing demand for the development of functional decorations that combine decorative patterns such as designs and motifs, which are the conventional applications of the water transfer method, with electrical circuit patterns, which are achieved by applying methods such as those described in Patent Documents 1 and 2. As methods for combining a decorative layer and an electrical circuit pattern, methods such as forming an electrical circuit pattern on the object to be transferred using the methods described in Patent Documents 1 and 2, and then laminating a decorative layer on the electrical circuit pattern using a known method, or forming a decorative layer on the object to be transferred in advance and then transferring the electrical circuit pattern onto the decorative layer can be applied. However, since the formation processes for the electrical circuit pattern and the decorative layer must be carried out separately, from the viewpoint of productivity, a method of water transfer processing using a water transfer sheet in which the electrical circuit pattern and decorative layer have been pre-laminated is advantageous.

[0007] However, when using a water transfer sheet with pre-formed electrical circuit patterns and decorative layers, it was necessary to ensure that the patterns and designs of the decorative layer were not obstructed by the lamination with the electrical circuit patterns. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Patent No. 5472098 [Patent Document 2] Japanese Patent Publication No. 2016-060089 [Overview of the project] [Problems that the invention aims to solve]

[0009] Therefore, the inventors considered that by making the electrical circuit pattern transparent, the design constraints that arise with colored electrical circuit patterns would be eliminated, and that decorative layers could be freely designed while being combined with the electrical circuit pattern. However, it was found that although it is possible to make the electrical circuit pattern transparent with conventional transparent conductive ink, it is difficult to ensure water transfer processing compatibility and conductivity (avoidance of disconnection).

[0010] Accordingly, the present invention has been made in view of the above circumstances, and in obtaining a water transfer product having a functional decorative layer formed by a composite of a transparent conductive pattern and a decorative layer, the first object is to provide a water transfer sheet having a conductive pattern layer that is excellent in water transfer processability and conductivity. The second object of the present invention is to provide a water transfer sheet having a transfer layer that is a composite of a conductive pattern and a decorative layer that is excellent in water transfer processability and conductivity.

[0011] Furthermore, a third object of the present invention is to provide a hydrotransfer product that includes a conductive pattern alone, or a functional decorative layer which is a composite of a conductive pattern and a decorative layer, by a hydrotransfer method using a hydrotransfer sheet of the first or second object. [Means for solving the problem]

[0012] To solve the above problems, the water transfer sheet of the present invention has a transfer layer on the surface of a water-soluble film which has at least a conductive pattern layer, the conductive pattern layer is made of a transparent conductive ink, and the conductive ink is composed of a conductive component selected from the group consisting of polythiophene compounds, polyaniline compounds, and graphene.

[0013] Since the conductive pattern layer is made of a transparent conductive ink containing a conductive component selected from the group consisting of polythiophene compounds, polyaniline compounds, and graphene, it can be flexibly stretched during water transfer processing, resulting in a water transfer sheet with a conductive pattern layer that has good water transfer processability and conductivity without breakage.

[0014] Furthermore, it is preferable that the water transfer sheet of the present invention has a structure in which the transfer layer further comprises a printed pattern layer, and the printed pattern layer is laminated on at least a portion of the conductive pattern layer. This makes it possible to obtain a water transfer sheet having a transfer layer which is a composite of a conductive pattern layer and a printed pattern layer, which has excellent water transfer processability and conductivity.

[0015] Furthermore, it is preferable that the water transfer sheet of the present invention has a structure in which the transfer layer further comprises a printed pattern layer, and the printed pattern layer is arranged so as not to be laminated on the conductive pattern layer. This makes it possible to obtain a water transfer sheet having a transfer layer in which the conductive pattern layer is composited with the printed pattern layer as a design.

[0016] Furthermore, it is preferable that the printed pattern layer in the water transfer sheet of the present invention contains a carbon-based conductive component. This imparts conductivity to the printed pattern layer, thereby electrically connecting the conductive pattern layer and the printed pattern layer, resulting in a water transfer sheet having a transfer layer with a complex conductive pattern structure synchronized with the printed pattern layer.

[0017] Furthermore, it is preferable that the conductive pattern layer in the water transfer sheet of the present invention has a structure in which at least a portion of it consists of multiple conductive pattern elements stacked and arranged via an insulating layer. This allows the conductive pattern layer to unfold a conductive pattern three-dimensionally in the thickness direction of the water transfer sheet, resulting in a water transfer sheet with a transfer layer that forms a complex conductive pattern structure synchronized with the printed pattern layer.

[0018] Furthermore, it is also preferable that the conductive pattern layer in the hydrographic transfer method of the present invention be any of the following: an electrical circuit, a capacitor, a capacitive switch, an antenna, a radio frequency identification element, or a coil. This makes it possible to obtain a hydrographic transfer sheet for forming a device consisting of an electrical circuit, a capacitor, a capacitive switch, an antenna, or a coil, either individually or in combination with other types, by hydrographic transfer.

[0019] Furthermore, the present invention relates to a water transfer method in which an activator is applied to a water transfer sheet having a transfer layer with at least a conductive pattern layer on the surface of a water-soluble film, the sheet is placed on the water surface of a water transfer tank, the object to be transferred is pressed against the water transfer sheet, and the conductive pattern layer is transferred to the surface of the object to be transferred by water pressure to obtain a water transfer product. The conductive pattern layer consists of a transparent conductive ink, and the conductive ink contains a conductive component selected from the group consisting of polythiophene compounds, polyaniline compounds, and graphene. By this water transfer method, a water transfer product can be obtained in which the conductive pattern is transferred to the object to be transferred in good condition without interruption.

[0020] Furthermore, in the water transfer method of the present invention, it is also preferable that the activator is a solvent-based activator composition. This optimizes the water transfer processability, making it possible to obtain a water transfer product in which the conductive pattern is transferred to the material without interruption and in good condition.

[0021] Furthermore, in the water transfer method of the present invention, it is also preferable that the conductive component is a polythiophene-based compound and the activator is an aqueous activator composition. This optimizes the water transfer processability when the polythiophene-based compound is dispersed in water in a conductive ink, making it possible to obtain a water transfer product in which the conductive pattern is transferred to the substrate in good condition without interruption.

[0022] Furthermore, in the water transfer method of the present invention, it is also preferable that the object to be transferred has an electrical circuit on its surface, and that at least a portion of the conductive pattern layer is transferred in a way that allows current to flow through it to the electrical circuit. This makes it possible to obtain a water transfer product that functions as a composite device of the transferred conductive pattern layer and the electrical circuit provided on the surface to be transferred.

[0023] In addition, in the above-described hydrostatic transfer method of the present invention, the hydrostatic transfer sheet may further include a printed pattern layer. Thereby, a hydrostatic transfer product provided with a functional decorative layer in which the conductive pattern layer and the printed pattern layer are combined can be obtained. The printed pattern layer may have a structure laminated on at least a part of the conductive pattern layer, or may have a structure arranged so as not to be laminated.

Advantages of the Invention

[0024] According to the present invention, since the hydrostatic transfer sheet includes a conductive pattern layer made of a transparent conductive ink containing a conductive component selected from the group consisting of polythiophene-based compounds, polyaniline-based compounds, and graphene, the conductive pattern layer is excellent in hydrostatic transfer processability and conductivity. By performing hydrostatic transfer processing on a transfer target using this hydrostatic transfer sheet, a hydrostatic transfer product provided with a conductive functional layer having a transparent conductive pattern layer without disconnection on the surface can be obtained. Further, by providing the hydrostatic transfer sheet with a structure further including a printed pattern layer, a hydrostatic transfer product provided with a conductive functional layer that functions as a functional decorative layer in which the conductive pattern layer and the printed pattern layer are combined can be obtained. Since the conductive pattern layer is transparent, even in a configuration laminated with the printed pattern layer, the design property is not impaired, so that various ornaments in which the design property and the electrical functionality are combined can be provided.

Brief Description of the Drawings

[0025] [Figure 1] It is a schematic enlarged cross-sectional view showing a first embodiment of the hydrostatic transfer sheet of the present invention. [Figure 2] In the first embodiment of the hydrostatic transfer sheet of the present invention, it is a schematic enlarged cross-sectional view showing a configuration example in which a transfer layer has an insulating layer. [Figure 3] In the first embodiment of the hydrostatic transfer sheet of the present invention, it is a schematic enlarged cross-sectional view showing a configuration example in which a transfer layer is formed by laminating a plurality of conductive pattern layers via an insulating layer. [Figure 4] It is a schematic enlarged cross-sectional view showing a second embodiment of the hydrostatic transfer sheet of the present invention. [Figure 5] This is a schematic enlarged cross-sectional view showing a configuration example of a third embodiment of the present invention, in which the printed pattern layer is arranged on the same layer surface as the conductive pattern layer, and the printed pattern layer is included in the transfer layer of the water transfer sheet of the present invention. [Figure 6] This is a schematic enlarged cross-sectional view showing a configuration example in which a printed pattern layer is laminated on a conductive pattern layer, which is one of the third embodiments of the present invention that includes a printed pattern layer in the transfer layer of the water transfer sheet. [Figure 7] This is a schematic diagram of the water pressure transfer method implemented in the present invention. [Figure 8] This is an explanatory diagram illustrating each step of the hydrographic transfer method of the present invention. [Figure 9] This is a schematic enlarged cross-sectional view showing an example of the structure of a hydrographic product obtained by the hydrographic transfer method of the present invention. [Figure 10] This is a plan view showing the arrangement of the conductive pattern layer and the printed pattern layer in Example 8 of the present invention. [Figure 11] This is a schematic diagram illustrating the configuration of the transfer layer in Embodiment 9 of the present invention. Figures 11(a) to (c) are plan views showing the conductive pattern (i) layer, insulating layer, and conductive pattern (ii), respectively. Figure 11(d) is a plan view showing the configuration of the transfer layer, and Figure 11(e) is a schematic cross-sectional view of AA' in Figure 11(d). [Modes for carrying out the invention]

[0026] The hydrographic transfer sheet and hydrographic transfer method of the present invention will be described in detail below.

[0027] 1. Water transfer sheet The water transfer sheet according to the present invention has a transfer layer on the surface of a water-soluble film, the conductive pattern layer being made of a transparent conductive ink, and the conductive ink is composed of a conductive component selected from the group consisting of polythiophene compounds, polyaniline compounds, and graphene. A first embodiment of the water transfer sheet will be described below with reference to Figures 1 to 3.

[0028] As shown in Figure 1, the water transfer sheet 20 of the first embodiment of the present invention has a conductive pattern layer 40 formed as a transfer layer 70 on the surface of a water-soluble film 30.

[0029] (Water-soluble film) The water-soluble film 30 constituting the water transfer sheet 20 is made of a water-soluble resin and serves as a base material for holding the conductive pattern layer 40. It swells and expands when in contact with water, and is removed by washing with water after water transfer. Examples of water-soluble resins include polyvinyl alcohol resin, dextrin, gelatin, glue, casein, shellac, gum arabic, starch, protein, polyacrylamide, sodium polyacrylate, polyvinyl methyl ether, copolymer of methyl vinyl ether and maleic anhydride, copolymer of vinyl acetate and itaconic acid, polyvinylpyrrolidone, acetylcellulose, acetylbutylcellulose, carboxymethylcellulose, methylcellulose, hydroxyethylcellulose, and sodium alginate. These resins may be used individually or in mixtures of two or more. Polyvinyl alcohol is particularly preferred from the viewpoint of production stability, solubility in water, and economic efficiency. Polyvinyl alcohol can be selected and applied from those conventionally used for water transfer sheets, depending on factors such as ease of forming the decorative layer, handling and storage properties including mechanical strength and moisture resistance, and water absorption and extensibility after floating on the water surface during water transfer.

[0030] (Conductive pattern layer) The conductive pattern layer 40, which constitutes the transfer layer 70 of the water transfer sheet 20, is formed on the surface of the water-soluble film 30 in a desired pattern using a transparent conductive ink by known methods such as screen printing or inkjet printing. Examples of patterns formed with conductive ink (conductive patterns) include circuit wiring patterns, coils, antennas, capacitive switches, and radio frequency identification elements (RFID). The conductive pattern layer 40 also has lands for electrically connecting to control circuits, power supplies, and other circuits after the transfer layer has been transferred to the object by water transfer. The resistance values ​​of the conductive patterns are set appropriately according to the application. It is also possible to adjust the resistance values ​​of a part of the conductive pattern to make it function as a thin-film heater. The conductive pattern layer 40 is transparent, and the total light transmittance of visible light in the wavelength range of 380 to 780 nm (according to JIS K7105 "Test Methods for Optical Properties of Plastics") is preferably 80% or more, more preferably 85% or more, and particularly preferably 90% or more. In this invention, transparent includes colorless transparent, colored transparent, and translucent.

[0031] The transparent conductive ink for forming the conductive pattern layer 40 mainly consists of a conductive component and a dispersion medium, and is composed of a conductive component selected from the group consisting of polythiophene compounds, polyaniline compounds, and graphene, either alone or in combination with other conductive components, from the viewpoint of ensuring transparency and conductivity while achieving good processability during water transfer.

[0032] Polythiophene compounds are polymers containing polymerization units having a structure obtained by polymerizing thiophene or its derivatives. Examples of thiophene derivatives include derivatives having substituents at the 3rd and 4th positions of the thiophene ring, with 3,4-ethylenedioxythiophene being a specific example. Typical modes of polymerization of thiophene or its derivatives in polythiophene compounds include bonding to other rings at the 2nd and 5th positions of the thiophene ring, with polyethylenedioxythiophene (PEDOT) being a specific example in which the thiophene ring is bonded to other rings at the 2nd and 5th positions. Polythiophene compounds may also have polymerization units other than thiophene units.Examples of polythiophene compounds include poly(thiophene), poly(3-methylthiophene), poly(3-ethylthiophene), poly(3-propylthiophene), poly(3-butylthiophene), poly(3-hexylthiophene), poly(3-heptylthiophene), poly(3-octylthiophene), poly(3-decylthiophene), poly(3-dodecylthiophene), poly(3-octadecylthiophene), poly(3-bromothiophene), poly(3-chlorothiophene), and poly(3-iodine). Poly(3-Cyanothiophene), Poly(3-Phenylthiophene), Poly(3,4-Dimethylthiophene), Poly(3,4-Dibutylthiophene), Poly(3-Hydroxythiophene), Poly(3-Methoxythiophene), Poly(3-Ethoxythiophene), Poly(3-Butoxythiophene), Poly(3-Hexyloxythiophene), Poly(3-Heptyloxythiophene), Poly(3-Octyloxythiophene), Poly(3-Decyloxythiophene), Poly(3-Dodecyl Poly(3-octadecyloxythiophene), poly(3,4-dihydroxythiophene), poly(3,4-dimethoxythiophene), poly(3,4-diethoxythiophene), poly(3,4-dipropoxythiophene), poly(3,4-dibutoxythiophene), poly(3,4-dihexyloxythiophene), poly(3,4-diheptyloxythiophene), poly(3,4-dioctyloxythiophene), poly(3,4-didecyloxythiophene), poly(3,4-di Poly(dodecyloxythiophene), poly(3,4-ethylenedioxythiophene), poly(3,4-propylenedioxythiophene), poly(3,4-butenedioxythiophene), poly(3-methyl-4-methoxythiophene), poly(3-methyl-4-ethoxythiophene), poly(3-carboxythiophene), poly(3-methyl-4-carboxythiophene), poly(3-methyl-4-carboxyethylthiophene), poly(3-methyl-4-carboxybutylthiophene), etc. are applicable.

[0033] Polyaniline compounds include polyaniline and polyaniline derivatives. Examples of aniline derivatives include (i) o-substituted anilines such as o-methylaniline, o-ethylaniline, o-phenylaniline, o-methoxyaniline, and o-ethoxyaniline, or (ii) m-substituted anilines such as m-methylaniline, m-ethylaniline, m-methoxyaniline, m-ethoxyaniline, and m-phenylaniline. Polyaniline compounds may also be doped with protonic acids or other dopants.

[0034] Graphene is a sheet of sp2-bonded carbon atoms with a thickness of one atom, and there are single-layer graphene and multilayer graphene. The number of layers in multilayer graphene is, for example, about 2 to 200, preferably 3 to 50. The maximum dimension in the plane direction of graphene is, for example, about 1 to 100 μm, and known graphene used as conductive ink for forming transparent conductive films can be applied.

[0035] Furthermore, since the water-soluble film 20 side of the conductive pattern layer 40 is exposed after water transfer, an insulating layer may be formed on the water-soluble film 20 side surface of the conductive pattern layer 40, as shown in Figure 2(a). Also, from the viewpoint of leveling the conductive pattern layer, if there are gaps in the conductive pattern of the conductive pattern layer, it is preferable to fill those gaps with insulating material, as shown in Figures 2(b) and (c). The material constituting the insulating layer consists of a resin component that exhibits extensibility due to the activator used in water transfer, and known resin components to which water transfer sheets are applied can be used. For example, acrylic resin, polyester resin such as alkyd, unsaturated polyester resin, urethane resin (e.g., polyester urethane resin), polycarbonate resin, polyvinyl chloride-vinyl acetate copolymer, polyvinyl acetal (butyral resin) such as polyvinyl butyral, and nitrocellulose resin such as nitrated cotton can be used.

[0036] Furthermore, the conductive pattern may be configured by laminating it with an insulating layer in between, as shown in Figure 3. Via holes can be formed in the insulating layer to electrically connect multiple conductive pattern layers formed at different layer positions using vias. In this case, if transparency of the transfer layer is to be ensured, it is preferable to use a transparent conductive ink that can be applied to the conductive pattern layer 40 as the material for the vias. Also, in embodiments where the transfer layer is combined with a printed pattern layer as described later, if the via portion is concealed by the printed pattern or if the via portion is used as a design element, it may be formed from a conductive material such as a carbon-based colored ink that can be stretched by water transfer. Specific examples of conductive pattern layers with a laminated conductive pattern structure include thin-film capacitors, multilayer thin-film coils, and thin-film transistors. The insulating layer consists of at least a resin component that exhibits stretchability with an activator used in water transfer, and known resin components used in water transfer sheets can be applied. Examples include acrylic resin, polyester resins such as alkyds, unsaturated polyester resins, urethane resins (e.g., polyester-urethane resins), polycarbonate resins, polyvinyl chloride-vinyl acetate copolymers, polyvinyl acetals (butyral resins) such as polyvinyl butyral, and nitrocellulose resins such as nitrated cotton. The thickness and resistance of the insulating layer should be set appropriately so that electrical short circuits do not occur between the conductive pattern layers.

[0037] Furthermore, as a second embodiment of the water transfer sheet of the present invention, as shown in Figure 4, the water transfer sheet 20 may have an adhesive-granulating resin layer 65 laminated on the side of the conductive pattern layer 40 opposite to the water-soluble film 30 side in order to improve the adhesion between the conductive pattern layer 40 and the object to be transferred. The adhesive-granulating resin layer 65 may be laminated with the gaps in the conductive pattern layer 40 filled with an insulating layer, as shown in Figure 4(a), or it may be formed by laminating it so that it also functions as an insulating layer, filling the gaps in the conductive pattern layer 40, as shown in Figure 4(b). Here, "granting adhesive" means improving the interfacial adhesion between the conductive pattern layer and the surface of the object to be transferred, and does not necessarily require the adhesive properties of a so-called adhesive. The adhesive-granulating resin layer 65, like the insulating layer described above, consists of a resin component that exhibits extensibility by an activator used in water transfer, and known resin components to which water transfer sheets are applied can be used. For example, acrylic resins, polyester resins such as alkyds, unsaturated polyester resins, urethane resins (e.g., polyester-urethane resins), polycarbonate resins, polyvinyl chloride-vinyl acetate copolymers, polyvinyl acetals (butyral resins) such as polyvinyl butyral, and nitrocellulose resins such as nitrated cotton can be used.

[0038] Furthermore, as a third embodiment of the water transfer sheet of the present invention, the transfer layer 70 may be configured to include a conductive pattern layer 40 and a printed pattern layer 50. The printed pattern layer 50 can be appropriately selected from configurations in which it is arranged so as not to overlap with the conductive pattern layer 40 (also called surface arrangement), configurations in which it is laminated so as to overlap with the conductive pattern layer 40, or configurations that combine these.

[0039] (Print pattern layer) The printed pattern layer 50 constituting the transfer layer 70 of the water transfer sheet 20 is formed by printing or coating a printed pattern using conventional water transfer sheet ink on the surface of a water-soluble substrate using known methods such as gravure printing, inkjet printing, or offset printing, and then drying it. This printed pattern includes not only patterns in the strict sense but also plain (unpatterned) printed patterns. The ink for the water transfer sheet mainly consists of a resin composition that can be softened with an activator used in water transfer to exhibit extensibility and adhesion. Examples of specific resin compositions include various oils and fats such as linseed oil, soybean oil, and synthetic drying oils; natural resins such as rosin, cured rosin, rosin esters, and polymerized rosin; synthetic resins such as phenolic resins, rosin-modified phenolic resins, maleic acid resins, alkyd resins, petroleum resins, vinyl resins, acrylic resins, polyamide resins, epoxy resins, aminoalkyd resins, and fluororesins; cellulose derivatives such as nitrocellulose, cellulose acetate butyrate resins, and ethylcellulose; rubber derivatives such as chlorinated rubber and cyclized rubber; and other materials such as casein, dextrin, and zein, but short-oil alkyd resins, nitrocellulose, and cellulose acetobutyrate are preferred. The resin composition may be colored or transparent and uncolored.

[0040] As an example of a transfer layer 70 in which the printed pattern layer 50 is arranged so as not to overlap with the conductive pattern layer 40, as illustrated in Figure 5, the printed pattern layer 50 is arranged in the gap of the conductive pattern layer 40, and this configuration is effective when a conductive pattern is provided in the blank (margin) portion of the printed pattern layer to integrate it with the design. For example, if the pattern of the printed pattern layer 50 includes a spiral pattern, a coil synchronized with the pattern can be formed by forming the conductive pattern layer 40 in the margin portion adjacent to the spiral printed pattern layer 50. Furthermore, in this configuration, the printed pattern layer 50 also functions as an insulating layer.

[0041] Furthermore, as a transfer layer 70 in which the printed pattern layer 50 is laminated so as to overlap the conductive pattern layer 40, a structure in which the printed pattern 50 is laminated on at least one side of the conductive pattern layer 40 can also be used, as illustrated in Figure 6. Since the conductive pattern layer 40 is transparent, the printed pattern layer 50 may be placed on the opposite side of the conductive pattern layer 40 from the water-soluble film 30 side, as shown in Figure 6(a), or it may be placed on the water-soluble film 30 side, as shown in Figure 6(b). In the configuration of Figure 6(a), the printed pattern layer 40 can also function as an adhesion-granulating layer in the second embodiment of the water transfer sheet described above. Also, in the configuration of Figure 6(a), the printed pattern layer 50 can also function as an insulating layer.

[0042] Furthermore, the printed pattern layer 50 may not only function as an insulating layer, but at least a portion of it may be made conductive, functioning as a design element while being electrically connected to the conductive pattern layer 40. The portion of the printed pattern layer 50 that is made conductive is formed by printing with a colored conductive ink. As the colored conductive ink, carbon-based pigments such as carbon black, carbon nanocoils, and carbon nanofibers, black pigments such as titanium black, white pigments such as zinc oxide, and conductive pigments such as metal powders or fibers such as silver and copper can be dispersed in a resin.

[0043] Furthermore, the transfer layer 70 may be configured to include various other functional layers, as long as it does not impair the effects of the present invention. For example, by laminating a metal vapor deposition layer on the side of the conductive pattern layer 40 opposite to the water-soluble film 30 side, or by laminating the conductive pattern layer 40 and a metal layer with the printed pattern layer 40 as an intermediate layer, a metallic or composite design with metallic elements can be obtained. In addition, an optical functional layer such as an anti-reflective or anti-glare layer may be placed on the water-soluble film 30 side of the conductive pattern layer 40.

[0044] Next, a hydrographic transfer method using the hydrographic transfer sheet of the present invention will be described.

[0045] 2. Water transfer method Figure 7 schematically shows the water transfer method of the present invention. This water transfer method is carried out using a water transfer sheet 20 of the present invention, in which a transfer layer 70 is formed on the surface of a water-soluble film 30, comprising a conductive pattern layer 40 made of a transparent conductive ink containing a conductive component selected from the group consisting of polythiophene compounds, polyaniline compounds, and graphene compounds. An activator 90 is applied to the transfer layer 70 of the water transfer sheet 20 (not shown), and the water transfer sheet 20 is supplied onto water 80 in a transfer tank with the transfer layer 70 facing upwards to float. The object to be transferred 10 is pushed into the water 80 via the water transfer sheet 20 to perform water transfer, thereby transferring and forming the conductive pattern layer 40T on the surface of the object to be transferred 10. The transfer layer 70 constituting the water transfer sheet 20 may be in a form consisting only of the conductive pattern layer 40, or in a form in which the conductive pattern layer 40 and the printed pattern layer 50 are combined. A detailed explanation of the conductive pattern layer 40 and the printed pattern layer 50 will be omitted as it will overlap with the explanation for the water transfer sheet.

[0046] The activator 90 used in the water transfer method of the present invention has the role of penetrating the entire transfer layer 70, which is equipped with a conductive pattern layer 40 and a printed pattern layer 50, and making it expandable in the water transfer process, and also functions as an adhesive component that brings the surface of the object to be transferred 10 and the transfer layer 70 into close contact. Known activator compositions used in conventional water transfer methods, such as solvent-based, photocuring-based, and thermo-curing-based activators, can be used. For example, a solvent-based activator is a composition containing a resin component, a solvent component, and a plasticizer component as essential components, and this composition may further contain fine silica particles. The resin component preferably contains nitrocellulose and a short-oil alkyd resin, the solvent component can be toluene, butyl cellosolve, butyl carbitol acetate, etc., and the plasticizer component can be dibutyl phthalate, etc.

[0047] The photocuring activator is a liquid composition containing at least a photopolymerizable monomer and a photopolymerization initiator. This photocuring activator is applied to a transfer layer 70 equipped with a conductive pattern layer 40 or a printed pattern layer 50 formed on a water-soluble film 30, penetrates it, and is transferred by water pressure. After curing by irradiation with active energy rays, it integrates with the transfer layer 70 and hardens, thereby forming a topcoat-free conductive pattern layer with chemical and mechanical surface protection functions such as solvent resistance and abrasion resistance. The photocurable activator consists of an active energy ray curable resin composition that hardens with ultraviolet light or electron beams, and for example, contains at least a monomer that polymerizes with active energy rays (also called a photopolymerizable monomer) and a photopolymerization initiator. If necessary, a photopolymerizable oligomer (prepolymer) may be added to improve the strength and chemical resistance of the decorative layer. Furthermore, compositions that harden using a so-called dual-cure method, combining these active energy ray curing and thermosetting types, can also be applied as the photocuring activator of the present invention. Furthermore, it is preferable to use a photopolymerizable monomer having an ink solubility of 9 or higher in SP value for the photocuring activator. This allows the photopolymerizable prepolymer, which has a higher viscosity than the photopolymerizable monomer, to be well dissolved and adjusted to a viscosity that is easy to handle, even when a photopolymerizable prepolymer, which has a higher viscosity than the photopolymerizable monomer, is blended with the photocuring activator. At the same time, the solubility of the photopolymerizable component of the photocuring activator can be brought closer to that of the ink composition of the conductive pattern layer 40 and the printed pattern 50. This ensures that the activator can be smoothly applied to these ink compositions (smooth application) and that the activator component can be well penetrated into the ink composition (penetration). In addition, leveling agents, defoamers, ultraviolet absorbers, stabilizers, etc., may be added to the photocuring activator as needed.

[0048] Next, each step constituting the hydrographic transfer method according to the embodiment of the present invention will be described in detail with reference to Figure 8.

[0049] (1) Activator coating process In the activator coating process, first, as shown in Figure 8(a), a water transfer sheet 20 is prepared, which has a transfer layer 70 containing a conductive pattern layer 40 on a water-soluble film (carrier film) 30. Next, as shown in Figure 8(b), an activator 90 is applied to the transfer layer 70 of the water transfer sheet 20 to activate the transfer layer 70 containing the conductive pattern layer 40. As a method for applying the activator 90, known methods such as the conventional Miyabar, Kiss Touch reverse coater method, and spray method can be applied.

[0050] (3) Water transfer sheet application process The water transfer sheet landing process involves supplying the water transfer sheet 20, whose transfer layer 70 has been activated with an activator 90, so that the surface of the water-soluble film 30 on which the transfer layer 70 is not formed lands on the surface of the water 80, thereby bringing the water transfer sheet 20 into contact with the water 80 and supporting it by floating in the water 80, as shown in Figure 8(c). The means for transporting and supplying the water transfer sheet 20 to the water 80 are not particularly limited, and conventional methods used in water transfer can be applied, including transporting it by hand.

[0051] (4) Transfer process As shown in Figure 8(d), the transfer process involves spreading the entire water transfer sheet 20, which is suspended and supported in water 80 during the water transfer sheet dwelling process, on the water surface, and pushing it into the water together with the water transfer sheet 20 so that the surface of the object to be transferred 10 is pressed against the activated transfer layer 70, thereby transferring the activated transfer layer 70 to the surface of the object to be transferred 10. In this process, the activated transfer layer 70 is transferred to the surface of the object to be transferred 10, resulting in a water transfer layer 70T with a conductive pattern layer 40T (corresponding to the conductive functional layer of the water transfer product described later), as shown in Figure 8(e).

[0052] (5) Washing and drying process Furthermore, the water transfer method according to the present invention may include a washing step and a drying step. Specifically, in the washing step shown in Figure 8(f), the water-soluble film 30 adhering to the surface of the water transfer layer 70T is washed away with a water flow rw by a washing device W, and then, in the drying step shown in Figure 8(g), a heater H is used to apply a hot wire (hot air) h to remove moisture and dry the material. As a result, the unnecessary water-soluble film 30 is removed, and a water transfer product 100 is obtained in which a conductive functional layer (not shown) with a conductive pattern layer 40T is formed on the surface of the material to be transferred 10. In addition, by using various configurations for the transfer layer 70 in Figure 8(a) as exemplified in the explanation of the water transfer sheet, water transfer products 100 with various conductive functional layers corresponding to those transfer layers 70 can be obtained.

[0053] (6)Curing process Furthermore, if a photocurable activator is used as the activator 90, after the transfer process, the water pressure transfer layer 70T formed on the surface of the object to be transferred 10 is irradiated with active energy rays such as ultraviolet light from the water-soluble film 30 side using an active energy ray irradiation device UL, as shown in Figure 8(h). This reacts with the photopolymerization component in the photocurable activator, causing the photopolymerization component and the transferred water pressure transfer layer 70T to blend together and harden, thereby performing a curing process to obtain a conductive functional layer equipped with a conductive pattern layer 40T.

[0054] The activator coating process may also be carried out by supplying the water transfer sheet 20 so that the side of the water-soluble film 30 on which the transfer layer 60 is not formed lands on the surface of the water 80, and then floating and supporting the water transfer sheet 20 in contact with the water 80. In this case, the activator 70 is coated by spraying.

[0055] Next, a hydrographic product obtained by the hydrographic transfer method according to the present invention will be described. As shown in Figure 9, the hydrographic product 100 has a conductive functional layer 7T formed on the surface of the transfer object 10, which includes a conductive pattern layer 40T formed by the hydrographic transfer method of the present invention. If a printed pattern layer is present, the conductive functional layer 7T functions as a decorative conductive functional layer 7T formed by combining the conductive pattern layer 40T and the printed pattern layer 50T. The conductive functional layer 7T is formed in various configurations depending on the arrangement combination of the conductive pattern layer 40, the printed pattern layer 50, etc., that constitute the transfer layer 70 of the hydrographic transfer sheet 20 of the present invention. For example, Figure 9(a) is an example of a conductive functional layer 7T when hydrographic transfer is performed using a hydrographic transfer sheet 20 in which the transfer layer 70 consists only of a conductive pattern layer 40, as in the first embodiment of the hydrographic transfer sheet of the present invention. Also, Figure 9(b) is an example of a conductive functional layer 7T when hydrographic transfer is performed using a hydrographic transfer sheet 20 in which the transfer layer 70 consists of a plurality of conductive pattern layers 40 laminated with an insulating layer in between, as in the first embodiment of the hydrographic transfer sheet of the present invention. Figure 9(c) shows an example of a conductive functional layer 7T when hydrotransferred using a hydrotransfer sheet 20, which is a second embodiment of the hydrotransfer sheet of the present invention, in which the transfer layer 70 has a configuration in which a conductive pattern layer 40 and an adhesive-granulating layer are laminated. Figure 9(d) shows an example of a conductive functional layer 7T when hydrotransferred using a hydrotransfer sheet 20, which is a third embodiment of the hydrotransfer sheet of the present invention, in which the transfer layer 70 has a configuration in which the conductive pattern layer 40 and the printed pattern layer 50 are arranged on the same layer. Figure 9(e) shows an example of a conductive functional layer 7T when hydrotransferred using a hydrotransfer sheet 20, which is a third embodiment of the hydrotransfer sheet of the present invention, in which the transfer layer 70 has a configuration in which the conductive pattern layer 40 and the printed pattern layer 50 are arranged on different layers. Furthermore, by forming the conductive pattern 40 constituting the transfer layer 70 as elements such as circuit wiring patterns, coils, antennas, capacitive switches, and radio frequency identification elements (RFID), a variety of functions can be imparted to the conductive functional layer 7T. [Examples]

[0056] The present invention will be described in detail below with reference to examples.

[0057] The methods for measuring the physical properties of the hydrographic transfer film and the hydrographic transfer product obtained using the hydrographic transfer method in the following examples and comparative examples, as well as the methods for evaluating the effects, are as follows.

[0058] (1) Suitability for water transfer printing (applicability) The printed pattern layer of a water transfer sheet was water-transferred onto the surface of a cylindrical test piece along its axial direction, and the ink coverage on the surface of the test piece was checked. In this test, because the object to be transferred is cylindrical, the pattern is subjected to considerable deformation stress during transfer. The degree and magnitude of this deformation stress vary depending on the properties of the ink, so the properties of the ink can be judged from the change in the pattern (ink coverage). The test piece was a cylindrical body made of cardboard ("Tochiman First Kent Paper F160," Tochiman is a registered trademark) with a diameter (outer diameter) of 30 mm and a length of 200 mm. The water transfer sheet, which had an activator applied to restore the adhesion of the transfer layer and was floating on the water surface, was submerged in water at a speed of 1.5 m / min from one end of the cylinder so that the central axis of the cylinder and the transfer water surface were approximately perpendicular, and the transfer state was visually confirmed and evaluated when the transfer layer was transferred to the circumference of the cylinder. The transfer state onto the cylindrical surface was evaluated as follows: excellent ("○") if there were no wrinkles and the transfer was continuous; good ("△") if there were wrinkles but the transfer was continuous without interruption; and poor ("×") if there were wrinkles and the transfer was interrupted.

[0059] (2) Conductivity of the conductive pattern layer of the water transfer printed product The resistance values ​​of the conductive pattern layers transferred onto the hydrographically printed samples in the examples and comparative examples were measured using a surface resistance meter (Mitsubishi Analytec MCP-T400). 10 7 Items less than Ω are considered acceptable ("○"), 10 7 Anything above Ω was marked as a failure ("×").

[0060] The conductive inks used to form the conductive pattern layer in this example and comparative example are shown in Table 1. Note that "Sepuljita" in Table 1 is a registered trademark of Shin-Etsu Polymer Co., Ltd.

[0061] [Table 1]

[0062] Hydrographic transfer samples of this example and the comparative example were prepared using the following procedure, and their effects were evaluated.

[0063] [Example 1] A water-soluble film made of polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Co., Ltd., model number C820) was used to obtain a water-soluble film with a water-soluble film made of polyvinyl alcohol. A solvent-based conductive ink (A1), in which poly(3,4-ethylenedioxythiophene) as described in Table 1 was dispersed as a conductive ink, was used to print a 5 μm thick conductive pattern layer using screen printing, and then dried to form a transfer layer. A water-soluble film with a transfer layer was obtained by applying a solvent-based activator (manufactured by Taica Corporation, CPA-H) at a wet weight of 15 g / m² to the entire transfer layer of this water-soluble film. 2 The transfer layer was activated by applying the material in this manner. Then, the water transfer sheet was floated in water from the water-soluble film side to stretch the water transfer film to a predetermined state, and the transfer target made of PC / ABS alloy material (Techni-Ace® PAX1439, 100 mm wide x 200 mm long x 3 mm thick, manufactured by A&L Japan Co., Ltd.) was pressed onto it and water transfer was performed to transfer the stretched transfer layer onto the transfer target. Subsequently, the water transfer product of Example 1 was obtained through a washing and drying process. The conductivity of the water transfer product of Example 1 was evaluated as described in (2) above. In addition, the suitability for water transfer was evaluated by water transfer to the cylindrical test piece described in (1) above instead of the transfer target made of PC / ABS alloy material.

[0064] [Example 2] In Example 1, the conductive ink (A1) was replaced with a water-based conductive ink (A2) containing dispersed poly(3,4-ethylenedioxythiophene), and the solvent-based surfactant was replaced with a water-based surfactant. Except for these differences, the water-press transfer product of Example 2 was obtained in the same manner as in Example 1. The conductivity of the water-press transfer product of Example 2 was evaluated as described in (2) above. Furthermore, the suitability for water-press transfer was evaluated by water-pressing the cylindrical test piece described in (1) above, instead of the PC / ABS alloy material as the transfer target.

[0065] [Example 3] In Example 1, a solvent-based conductive ink (A3) containing dispersed polyaniline was used instead of conductive ink (A1) as the conductive ink, but otherwise the same procedure as in Example 1 was followed to obtain the water-pressed product of Example 3. The conductivity of the water-pressed product of Example 3 was evaluated as described in (2) above. In addition, the suitability for water-press transfer was evaluated by water-pressing the cylindrical test piece described in (1) above instead of the PC / ABS alloy material to be transferred.

[0066] [Example 4] In Example 1, a solvent-based conductive ink (A4) containing dispersed graphene was used instead of conductive ink (A1) as the conductive ink, but otherwise the same procedure as in Example 1 was followed to obtain the water-pressed product of Example 4. The conductivity of the water-pressed product of Example 4 was evaluated as described in (2) above. In addition, the suitability for water-press transfer was evaluated by water-pressing the cylindrical test piece described in (1) above instead of the PC / ABS alloy material to be transferred.

[0067] [Example 5] In Example 1, a water transfer print was obtained in the same manner as in Example 1, except that a blue nitrocellulose-based transparent ink (PCNT, manufactured by Toyo Ink Co., Ltd.) was screen printed onto the entire surface of the conductive pattern opposite to the water-soluble film side to form a printed pattern layer. The conductivity of the water transfer print of Example 5 was evaluated as described in (2) above. In addition, the suitability for water transfer was evaluated by water transfer to the cylindrical test piece described in (1) above, instead of the PC / ABS alloy material to be transferred to.

[0068] [Example 6] In Example 5, the conductive ink was replaced with a solvent-based conductive ink (A3) containing dispersed polyaniline, except that the conductive ink (A1) was replaced with a water-pressed product of Example 6, in the same manner as in Example 1. The conductivity of the water-pressed product of Example 6 was evaluated as described in (2) above. In addition, the suitability for water-press transfer was evaluated by water-pressing the cylindrical test piece described in (1) above instead of the PC / ABS alloy material to be transferred.

[0069] [Example 7] In Example 5, the conductive ink (A1) was replaced with a solvent-based conductive ink (A4) containing dispersed graphene as the conductive ink, except that the procedure was the same as in Example 5 to obtain the water-pressed product of Example 7. The conductivity of the water-pressed product of Example 7 was evaluated as described in (2) above. In addition, the suitability for water-press transfer was evaluated by water-pressing the cylindrical test piece described in (1) above instead of the PC / ABS alloy material to be transferred.

[0070] [Example 8] In Example 1, the water transfer sheet was formed by arranging the conductive pattern layer 40 and the printed pattern layer 50 on a water-soluble film in a plan view pattern as shown in Figure 10 (the depiction of the water-soluble film is omitted), except that the transfer layer (70) of the water transfer sheet was the same as in Example 1. Here, the line width of the conductive pattern in the conductive pattern layer 40 was 2 mm, and the spacing between the conductive patterns was 2 mm. The conductive pattern layer 40 was formed by screen printing and dried, and then the printed pattern layer 50 was formed with a thickness of approximately 5 μm by screen printing using a blue nitrocellulose-based transparent ink (PCNT, manufactured by Toyo Ink Co., Ltd.). The conductivity of the water transfer product of Example 8 was evaluated as described in (2) above. In addition, the suitability for water transfer was evaluated by water transfer to the cylindrical test piece described in (1) above, instead of the PC / ABS alloy material to be transferred.

[0071] [Example 9] In Example 8, the conductive ink (A1) was replaced with a water-based conductive ink (A2) containing dispersed poly(3,4-ethylenedioxythiophene), and the solvent-based surfactant was replaced with a water-based surfactant. Except for these differences, the water-press transfer product of Example 9 was obtained in the same manner as in Example 8. The conductivity of the water-press transfer product of Example 9 was evaluated as described in (2) above. Furthermore, the suitability for water-press transfer was evaluated by water-pressing the cylindrical test piece described in (1) above, instead of the PC / ABS alloy material as the transfer target.

[0072] [Example 10] In Example 8, the water transfer product of Example 10 was obtained in the same manner as in Example 8, except that a solvent-based conductive ink (A3) containing dispersed polyaniline was used instead of conductive ink (A1) as the conductive ink. The conductivity of the water transfer product of Example 10 was evaluated as described in (2) above. In addition, the suitability for water transfer was evaluated by water transfer to the cylindrical test piece described in (1) above, instead of the PC / ABS alloy material to be transferred.

[0073] [Example 11] In Example 1, the water-press transfer product of Example 11 was obtained in the same manner as in Example 1, except that the transfer layer was configured in the order of conductive pattern (i) / insulating layer / conductive pattern (ii) / printed pattern layer from the water-soluble film side. The conductive pattern (i) layer and conductive pattern (ii) layer constituting the transfer layer are layers that are flattened by filling the remaining areas with an insulating layer and the coil patterns 40A and 40B shown in Figures 11(a) and (c). They are electrically connected by vias 40v formed in the insulating layer shown in Figure 11(b), and are formed from a laminated coil with the structure shown in the plan view of Figure 11(d) (the depiction of the printed pattern layer is omitted) and the cross-sectional view of Figure 11(e), and a printed pattern layer printed on the entire surface thereof. The line width of the conductive patterns of coil patterns 40A and 40B was 2 mm, and the spacing between the conductive patterns was 2 mm. Here, the insulating layer 60 was screen printed using a nitrocellulose-based transparent ink (PCNT S Medium C, manufactured by Toyo Ink Co., Ltd.), and the printed pattern layer was screen printed using a blue nitrocellulose-based transparent ink (PCNT, manufactured by Toyo Ink Co., Ltd.), with each layer having a thickness of approximately 5 μm. Following the procedure of printing the next layer after the screen-printed layer has dried, the conductive pattern (i) layer, insulating layer, conductive pattern (ii) layer, and printed pattern layer were formed in that order. The conductivity of the obtained water-transfer product of Example 11 was evaluated as described in (2) above. In addition, the suitability for water transfer was evaluated by water transfer to the cylindrical test piece described in (1) above, instead of the PC / ABS alloy material to be transferred to.

[0074] [Example 12] In Example 11, the conductive ink (A1) was replaced with a water-based conductive ink (A2) containing dispersed poly(3,4-ethylenedioxythiophene), and the solvent-based surfactant was replaced with a water-based surfactant. The water-press transfer product of Example 12 was obtained in the same manner as in Example 11. The conductivity of the water-press transfer product of Example 12 was evaluated as described in (2) above. Furthermore, the suitability for water-press transfer was evaluated by water-pressing the cylindrical test piece described in (1) above, instead of the PC / ABS alloy material as the transfer target.

[0075] [Example 13] In Example 11, the conductive ink (A1) was replaced with a solvent-based conductive ink (A3) containing dispersed polyaniline as the conductive ink, except that the procedure was the same as in Example 11 to obtain the water-pressed product of Example 13. The conductivity of the water-pressed product of Example 13 was evaluated as described in (2) above. In addition, the suitability for water-press transfer was evaluated by water-pressing the cylindrical test piece described in (1) above instead of the PC / ABS alloy material to be transferred.

[0076] [Comparative Example 1] In Example 1, a water-press transfer product of Comparative Example 1 was obtained in the same manner as in Example 1, except that a transfer layer consisting of a 50 nm thick sputtered indium tin oxide (ITO) film was used as a conductive pattern layer over the entire surface of the water-soluble film. The conductivity of the water-press transfer product of Comparative Example 1 was evaluated as described in (2) above. In addition, the suitability for water-press transfer was evaluated by water-press transfer to the cylindrical test piece described in (1) above, instead of the PC / ABS alloy material to be transferred to.

[0077] [Comparative Example 2] In Example 1, a water-pressed product of Comparative Example 2 was obtained in the same manner as in Example 1, except that a solvent-based conductive ink (A4) with dispersed carbon was used as the conductive ink instead of conductive ink (A1). The conductivity of the water-pressed product of Comparative Example 2 was evaluated as described in (2) above. In addition, the suitability for water-press transfer was evaluated by water-pressing the cylindrical test piece described in (1) above instead of the PC / ABS alloy material to be transferred.

[0078] The results for Examples 1-4 and Comparative Examples 1-2 are shown in Table 2, the results for Examples 5-10 are shown in Table 3, and the results for Examples 11-13 are shown in Table 4.

[0079] [Table 2]

[0080] [Table 3]

[0081] [Table 4]

[0082] From a comparison of the results of Examples 1-4 shown in Table 2 with Comparative Examples 1 and 2, it was found that water transfer sheets in which the conductive component of the conductive ink forming the conductive pattern layer of the transfer layer is a thiophene compound, a polyaniline compound, or graphene exhibit excellent transferability (adhesion) during water transfer, and the conductive pattern layer of the water transfer product obtained using such a sheet has good conductivity. On the other hand, as in Comparative Example 1, water transfer sheets in which the conductive pattern layer is an ITO sputtered film of an inorganic material exhibit significantly poor extensibility during water transfer, and the ITO film is transferred in a cracked state, resulting in the loss of conductivity of the conductive pattern layer formed on the water transfer product. Furthermore, as in Comparative Example 2, water transfer sheets equipped with a conductive pattern layer formed with a conductive ink using carbon as an organic conductive component exhibit excellent transferability, but the conductivity of the conductive pattern layer after transfer decreases. This indicates that even with organic transparent conductive components, achieving both transferability during water transfer and conductivity after transfer requires specific components, and it was confirmed that thiophene compounds, polyaniline compounds, and graphene are effective as conductive inks.

[0083] Furthermore, from the results of Examples 5 to 10 in Table 3, it was found that even in the water transfer sheets of Examples 5 to 7, which have a structure in which a conductive pattern layer and a printed pattern layer are laminated as the transfer layer of the water transfer sheet, and in the water transfer sheets of Examples 8 to 10, which have a structure in which the conductive pattern layer and the printed pattern layer are arranged on the same plane without lamination, applying thiophene compounds, polyaniline compounds, and graphene as conductive inks results in excellent transferability (adhesion) in water transfer, and the conductive pattern layer of the water transfer product obtained by water transfer using these inks has good conductivity.

[0084] Furthermore, the results from Examples 11 to 13 in Table 4 show that even in a water transfer sheet in which multiple conductive pattern layers are laminated via an insulating layer and a printed pattern layer is laminated as the transfer layer of the water transfer sheet, applying thiophene-based compounds, polyaniline-based compounds, and graphene as conductive inks results in excellent transferability (adhesion) in water transfer, and the conductive pattern layer of the water transfer product obtained by water transfer using these inks has good conductivity.

[0085] The present invention is not limited to the embodiments described above, and its technical scope includes various design modifications that do not depart from the gist of the invention as described in the claims. [Industrial applicability]

[0086] The water transfer sheet and water transfer method using the present invention enable the formation of transparent conductive patterns on curved surfaces of objects to be transferred, and do not impair the design of decorative layers when combined with them. This allows for functional decoration that harmonizes with and integrates with decorative patterns, making it useful as a novel decorative component with built-in electrical devices for use in car interiors, home appliances, and other applications. [Explanation of Symbols]

[0087] 10, 10a Transferred material 100 hydrographic prints 20 Water Transfer Sheets 30 Water-soluble film 40 Conductive pattern layer 40V conductive pattern via 4T conductive pattern layer (after transfer) 50 Print Pattern Layers 5T Printed pattern layer (after transfer) 60 Insulating layer 6T insulating layer (after transfer) 65 Adhesive layer 7T conductive functional layer 70 Transfer layer 70T hydrographic transfer layer 80 water 90 Activators UL Activated Energy Ray Irradiation Device (Ultraviolet Irradiation Device) UV (ultraviolet rays) S Washing device rw water flow H Drying equipment h Heat ray (hot air)

Claims

1. A water-soluble film having a transfer layer on its surface that includes at least a conductive pattern layer, The conductive pattern layer is made of a transparent conductive ink, and the conductive ink contains a conductive component selected from the group consisting of polythiophene compounds, polyaniline compounds, and graphene. The transfer layer further comprises a printed pattern layer, The water transfer sheet is characterized in that the printed pattern layer has (i) a structure laminated on at least a portion of the conductive pattern layer, or (ii) a structure arranged so as not to be laminated on the conductive pattern layer.

2. The water transfer sheet according to claim 1, characterized in that the printed pattern layer contains a carbon-based conductive component.

3. The hydraulic transfer sheet according to claim 1 or 2, characterized in that the conductive pattern layer has a structure in which at least a portion of a plurality of conductive pattern elements are stacked and arranged with an insulating layer in between.

4. The hydraulic transfer sheet according to any one of claims 1 to 3, characterized in that the conductive pattern layer is one of an electrical circuit, a capacitor, a capacitance switch, an antenna, a radio frequency identification element, or a coil.

5. In a water pressure transfer method for obtaining a water pressure transferred product, an activator is applied to a water pressure transfer sheet having a transfer layer with at least a conductive pattern layer on the surface of a water-soluble film, the sheet is placed on the water surface of a water pressure transfer tank, an object to be transferred is pressed against the water pressure transfer sheet, and the transfer layer is transferred to the surface of the object to be transferred by water pressure, The conductive pattern layer is made of a transparent conductive ink, and the conductive ink contains a conductive component selected from the group consisting of polythiophene compounds, polyaniline compounds, and graphene. The transfer layer further comprises a printed pattern layer, The water transfer method is characterized in that the printed pattern layer has (i) a structure laminated on at least a portion of the conductive pattern layer, or (ii) a structure arranged so as not to be laminated on the conductive pattern layer.

6. The water transfer method according to claim 5, characterized in that the activator is a solvent-based activator composition.

7. The water pressure transfer method according to claim 5, characterized in that the conductive component is a polythiophene compound and the activator is an aqueous activator composition.

8. The water pressure transfer method according to any one of claims 5 to 7, characterized in that the object to be transferred has an electrical circuit on the surface to be transferred, and at least a portion of the conductive pattern layer is transferred so as to be electrically conductive in contact with the electrical circuit.

Images