JP5455963B2 - Transfer sheet having transparent conductive film mainly composed of graphene and method for producing the same - Google Patents

Description

  The present invention relates to a transfer sheet having a transparent conductive film layer, and more particularly to a transfer sheet provided with a transparent conductive film containing graphene as a main component as a transparent conductive film layer and a method for producing the same.

  In communication devices such as mobile phones, electronic information devices, liquid crystal displays, solar cells, and the like, a transparent conductive film excellent in transparency and conductivity is required.

  Indium tin oxide (ITO) is mainly used for the transparent conductive material of the transparent conductive film. However, since ITO contains indium, which is a rare earth, alternative materials have been studied in terms of stable supply, environmental load, and the like.

  Carbon nanotubes (CNT), metal nanowires and the like are listed as candidates for ITO substitute materials. One of them is Graphene. Graphene is a two-dimensional material having a honeycomb structure in which carbon atoms are bonded to three adjacent carbon atoms. 2004, A.M. Geim and K.M. A lot of research has been done since Novoselov first isolated by mechanical exfoliation of highly oriented graphite with adhesive tape and experimentally proved the unique properties of graphene that were theoretically predicted so far (e.g. Patent Document 1).

  The graphene film is formed by winding a sheet-like Cu substrate (thickness 15 μm, 25 μm) as a catalyst around a cylindrical reactor and depositing the film on the Cu substrate by chemical vapor deposition (CVD) at 1000 ° C. It took many steps such as pasting with a long substrate capable of roll-to-roll method and removing the Cu substrate by etching (for example, Non-Patent Document 2). As described above, since many steps are required after the formation of the graphene, there is a problem in that the cost is high and the generated graphene film is wrinkled or torn, so that the conductivity of the graphene is lowered. In addition, there has been no method for forming a graphene film on a substrate by a consistent roll-to-roll method.

K. S. Novoselov, A.M. K. Geim et al. , Science, 306, 666 (2004). S. Bae et al. , Nature Nanotech. 5,574 (2010)

  The present invention has been made to solve the above problems, and its purpose is to transfer a graphene film on a substrate by a transfer sheet for producing a transparent conductive film using graphene as a conductive material and a consistent roll-to-roll method. The present invention provides a method for producing a transfer sheet on which is formed.

  In order to achieve the above object, the inventor has intensively studied. As a result, a metal thin film layer reflecting the smoothness of the base sheet is formed on the base sheet having smoothness and releasability, and graphene is formed thereon. It came to invent the transfer sheet for producing the transparent conductive material which used the graphene as the electrically conductive material in which the transparent conductive film layer which has a main component was formed, and its manufacturing method.

  Means for solving the above problems in the present invention will be described below.

  A first aspect of the present invention includes a base sheet having releasability and smoothness, a metal thin film layer partially or entirely formed on the base sheet so as to reflect the smoothness of the base sheet, It is a transfer sheet provided with the transparent conductive film layer which has a graphene as a main component and is formed on the said metal thin film layer.

  The second aspect of the present invention is a transfer sheet in which the metal thin film layer has a thickness of 0.01 to 1 μm.

  A third aspect of the present invention is a transfer sheet in which the arithmetic mean roughness (Ra) of the surface of the base sheet is 0.1 nm ≦ Ra ≦ 20 nm.

  A fourth aspect of the present invention is a transfer sheet, wherein the base sheet includes a base sheet and a release layer formed on the base sheet.

  A fifth aspect of the present invention is a transfer sheet further comprising an adhesive layer on the transparent conductive film layer.

  In a sixth aspect of the present invention, a step of partially forming a mask layer on a base sheet having releasability, and forming a metal thin film layer on the base sheet having the mask layer and the releasability A step of peeling and removing the metal thin film layer formed on the mask layer and the mask layer with a solvent to partially form the metal thin film layer on the substrate sheet; Forming a transparent conductive film layer mainly composed of graphene on a metal thin film layer partially formed on the sheet.

  According to a seventh aspect of the present invention, a step of forming a metal thin film layer on a base sheet, a resist layer is partially formed on the metal thin film layer, and the resist layer is formed on the metal thin film layer. Forming a portion where the resist layer is not formed, peeling off the metal thin film layer where the resist layer is not formed with a solvent, and partially removing the metal thin film layer on the base sheet Forming the resist layer, removing the resist layer using a solvent to expose the metal thin film layer on the surface, and forming graphene as a main component on the metal thin film layer exposed on the surface Forming a transparent conductive film layer to be produced.

  In the transfer sheet of the present invention, the surface of the base sheet having releasability is extremely smooth, and the thickness of the metal thin film layer formed on the base sheet having releasability is extremely thin. Reflecting the properties, the surface of the metal thin film layer is necessarily extremely smooth. Therefore, the surface of the metal thin film layer, which is the base and catalyst, is extremely smooth, so that the transparent conductive film layer formed on the surface is less likely to have pinholes and the like, and is a very thin transparent conductive film layer. Even if it exists, there exists an effect which can form stably. Moreover, there is an effect of improving the uniformity of the thickness of the transparent conductive film layer itself. In addition to this, the graphene constituting the transparent conductive film layer also has a function of extremely high transparency.

  As a result, if the transfer sheet of the present invention is used, there is an effect that a transparent conductor excellent in conductivity and transparency can be produced. Further, if the uniformity of thickness is improved, the generation of wrinkles and the like of the transparent conductive film layer at the time of transfer is reduced. Furthermore, since the thickness of the metal thin film layer is extremely thin, the removal process of the metal thin film layer after adhering to the transfer target is simplified, so that there is an effect that a high-quality transparent conductor can be manufactured with high productivity.

  Since the transfer sheet of the present invention uses a transparent conductive film layer mainly composed of flexible graphene, the transfer sheet can be formed on a flexible two-dimensional shape to be transferred, and a three-dimensional shape to be transferred. There is also an effect that can be formed on the body. Furthermore, since the metal thin film layer can be patterned in the transfer sheet formation stage, a patterned transparent conductive film layer can be obtained simply by removing the metal thin film layer after it is formed on the transfer target. Therefore, there is an effect that the patterning process of the transparent conductive film layer after being formed on the transfer object is unnecessary and the process can be greatly simplified.

FIG. 1 is a cross-sectional view of a transfer sheet according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view of a transfer sheet according to the second embodiment of the present invention. FIG. 3 is a cross-sectional view of a transfer sheet according to the third embodiment of the present invention. FIG. 4 is a cross-sectional view of a transfer sheet according to the fourth embodiment of the present invention. FIG. 5 is a cross-sectional view showing a first embodiment of a method for producing a transfer sheet according to the present invention. FIG. 6 is a cross-sectional view showing a second embodiment of the method for producing a transfer sheet according to the present invention. FIG. 7 is a cross-sectional view showing a transparent conductor according to the present invention. FIG. 8 is a cross-sectional view showing the transparent conductive manufacturing method according to the present invention.

  Hereinafter, embodiments according to the present invention will be described in more detail with reference to the drawings. It should be noted that the dimensions, materials, shapes, relative positions, etc. of the parts and portions described in the embodiments of the present invention are not intended to limit the scope of the present invention only to those unless otherwise specified. This is just an illustrative example.

  FIG. 1 is a view showing a transfer sheet according to the first embodiment of the present invention. The transfer sheet 1 of the present invention refers to a sheet on which a layer including the transparent conductive film layer 4 can be transferred to a transfer target 10 (including not only a two-dimensional shape but also a three-dimensional shape) by pressing or heating. . Referring to FIG. 1, a transfer sheet 1 of the present invention includes a base sheet 2 having a releasability, a metal thin film layer 3, a transparent conductive film layer 4, and an adhesive layer 5. The transfer sheet 1 of the present invention has a metal thin film layer 3 partially formed on a base sheet 2 having releasability, and has a transparent conductive film layer 4 along the metal thin film layer 3. An adhesive layer 5 is provided on the outermost surface.

[Base sheet]
The base sheet 2 having releasability is for supporting the metal thin film layer 3 and the transparent conductive film layer 4. The surface 2 of the base sheet having releasability has excellent smoothness. The arithmetic average roughness (Ra) of the surface of the base sheet 2 is preferably 0.1 nm ≦ Ra ≦ 20 nm. When the arithmetic average roughness (Ra) of the base sheet 2 having releasability exceeds 20 nm, the uneven shape on the surface of the metal thin film layer 3 formed on the base sheet 2 having releasability increases. On the contrary, there is a problem that the crystallinity is lowered due to the relatively small grain size of the graphene formed on the metal thin film layer 3 and the conductivity of the transparent conductive film layer 4 containing graphene as a main component is lowered. If the arithmetic average roughness (Ra) is less than 0.1 nm, the uneven shape on the surface of the base sheet 2 cannot be made uniform, and there is a problem that the release performance of the base sheet 2 is deteriorated. This is because there is a problem that the transparent conductive film layer cannot be transferred to the transfer body. The arithmetic average roughness (Ra) is based on Japanese Industrial Standard (JIS) B0601-1994.

  The thickness of the base sheet 2 having releasability is preferably 10 μm to 500 μm. If the thickness of the base sheet 2 having releasability is less than 10 μm, the rigidity of the base sheet 2 having releasability is lost, so that the metal thin film layer 3 and the transparent layer are formed on the base sheet 2 having releasability. When the conductive film layer 4 is formed, there arises a problem that the metal thin film layer 3 and the transparent conductive film layer 4 cannot be supported. However, since there is a correlation between the thickness of the base sheet and the unevenness of the surface thereof, when the thickness of the base sheet is more than a certain value, that is, when the thickness of the base sheet 2 having releasability exceeds 500 μm, the release is performed. This is because the shape of the surface of the base sheet 2 having the properties exceeds 20 nm in arithmetic average roughness (Ra), and the above-described problems occur.

  The material of the base sheet 2 having releasability is not particularly limited as long as it is a material having flexibility and heat resistance capable of withstanding heat generated when the transparent conductive film layer 4 described later is formed. Examples of such heat-resistant materials include polyimide, polyetherimide, polysulfone, polyethersulfone, polyetheretherketone, polyphenylene sulfide, polyethylene naphthalate, polyamideimide, polyarylate, high density polyolefin, Examples thereof include resins such as polycarbonate, polyethylene terephthalate, polyvinylidene fluoride, polyvinyl fluoride, polyvinylidene chloride, and liquid crystal polymer.

  When the material constituting the base sheet 2 does not have releasability, the base sheet 2 may be subjected to a release treatment. As a method of releasing the base sheet 2, (1) a method of subjecting the base sheet 2 to a low-pressure plasma treatment in an atmosphere of a fluorinated hydrocarbon compound, (2) an atmosphere of argon and acetone and / or helium, (3) A solid dielectric is placed on the surface of the counter electrode under an atmospheric pressure of a mixed gas composed of a fluorine atom-containing gas and an inert gas, and an electric field is applied between the counter electrodes. And a method of releasing the substrate sheet with the discharge plasma generated by the above method.

[Metal thin film layer]
The metal thin film layer 3 of the present invention provides the metal thin film layer 3 with a catalytic function for generating graphene, which is the main component of the transparent conductive layer 4, on the base sheet 2 having releasability and the smoothness of the base sheet 2. It is a layer with a function to reflect. As the material of the metal thin film layer 3, metals such as copper, nickel, ruthenium, iron, cobalt, iridium and platinum, and alloys thereof are used. From the viewpoint of reflecting the smoothness of the base sheet 2 having releasability in the metal thin film layer 3, the thickness of the metal thin film layer 3 of the present invention is preferably 0.01 to 1 μm. When the thickness of the metal thin film layer 3 is in the range of 0.01 μm to 1 μm, the smoothness of the base sheet 2 can be reflected, so that the surface of the metal thin film layer 3 becomes smooth and the graphene grains constituting the transparent conductive film layer 4 A graphene film having a relatively large size and good conductivity can be formed. In addition, when the thickness of the metal thin film layer 3 is in the range of 0.01 μm to 1 μm, when a transparent conductor composed of the transfer target and the transparent conductive film layer 4 is formed using the transfer sheet 1, In this process, the metal thin film layer 3 and the transparent conductive film layer 4 are transferred from the transfer sheet 1 to the transfer target, and only the metal thin film layer 3 is removed from the transfer target. The metal thin film layer 3 can be removed in a short time because it is much thinner than 15 μm and 25 μm).

[Transparent conductive film layer]
The transparent conductive film layer 4 of the present invention is a layer whose main component is composed of graphene. The fact that the main component is composed of graphene means that one or more graphene films occupy the most by weight ratio among the substances constituting the transparent conductive film layer. The transparent conductive film layer 4 may contain impurities. Examples of the impurities include amorphous carbon, metal of the metal thin film layer 4, and the like. The metal of the metal thin film layer 4 is a component that remains in the etching process after transfer to the transfer target. Moreover, the transparent conductive film layer 4 has conductivity, and is configured so that the light transmittance of wavelengths in the visible region is 80% or more as a whole. In addition, it is preferable that the thickness of the transparent conductive film layer 4 is 1 to 9 layers of graphene. It is because the transparency of the transparent conductive film layer 4 is inhibited when the number is 10 layers or more. The transparent conductive film layer 4 is formed only on the patterned metal thin film layer 3 by chemical vapor deposition (CVD) or the like.

[Adhesive layer]
The adhesive layer 5 is a layer for adhering the transfer target and the transfer sheet 1 and is formed on the surface of the transfer sheet 1 as necessary. The adhesive layer 5 is made of an acrylic or vinyl resin and has an insulating property. The insulating property here means, for example, a degree of not causing a short circuit that causes a malfunction of position detection in an input operation when the transparent conductive material 11 is a touch panel for the transparent conductive material 11 manufactured according to the present invention. It means the above insulation. The adhesive layer 5 is formed on the transfer sheet 1 by a gravure coating method, a roll coating method, a comma coating method, a gravure printing method, a screen printing method, an offset printing method, or the like.

  FIG. 2 is a view showing a transfer sheet according to the second embodiment of the present invention. Since the basic structure of the transfer sheet in this embodiment is the same as that of the transfer sheet according to the first embodiment, only the differences will be described here.

  Referring again to FIG. 2, the transfer sheet 1 of the present invention includes a base sheet 7, a release layer 6, a metal thin film layer 3, a transparent conductive film layer 4, and an adhesive layer 5. In the transfer sheet 1 of the present invention, a release layer 6 is formed on a base sheet 7, and there is a metal thin film layer 3 partially formed on the release layer 6, along the metal thin film layer 3. There is a transparent conductive film layer 4, and an adhesive layer 5 is provided on the uppermost surface.

[Base sheet]
The base sheet 7 is for supporting the metal thin film layer 3, the transparent conductive film layer 4, and the like. The surface of the base sheet 2 having releasability needs to have smoothness like the base sheet of the first embodiment. However, when the base sheet 7 does not have smoothness, the release layer 6 is required as shown below. In addition, even if it is a case where the base sheet 2 provided with mold release property has smoothness, you may provide the mold release layer 6. FIG.

[Release layer]
The release layer is a transfer sheet 1 together with the base sheet 7 when the transparent conductive film layer 4 or the like is transferred to the transfer target and the base sheet 2 having release properties is peeled from the transfer target. A layer that is peeled from the body. By forming the release layer 6 on the base sheet 7, the peeling weight (force required for peeling) of the base sheet 2 having releasability can be adjusted. In addition to this, by forming the release layer 6 on the base sheet 7, even if the surface of the base sheet 7 is uneven, the release layer 6 has unevenness on the surface of the base sheet 7. Since the base sheet is covered so as to be buried, the arithmetic surface roughness (Ra) of the surface of the release layer on which the metal thin film layer 3 is formed can be 1 nm ≦ Ra ≦ 20 nm. As a result, as in the case of the transfer sheet according to the first embodiment, there is a problem that the conductivity of the transparent conductive film layer 4 containing graphene as a main component is reduced, and a problem that the release performance of the release layer is reduced. It will not occur. The material of the release layer 6 has heat resistance that can withstand the heat generated during the formation of the transparent conductive film layer 4 and a predetermined release property. When the release layer 6 is formed on the base sheet 7, If the surface of the mold release layer 6 becomes excellent in smoothness, there will be no restriction | limiting in particular. Examples of the material for the release layer 6 include resins such as thermosetting acrylic, thermosetting polyester, thermosetting urethane, acrylic, epoxy, melamine, silicon, and fluorine. Examples of the method for forming the release layer 6 include coating by a roll coating method, a gravure printing method, a screen printing method, a die coating method, and the like.

  FIG. 3 is a view showing a transfer sheet according to the third embodiment of the present invention. Since the basic structure of the transfer sheet in this embodiment is the same as that of the transfer sheet according to the first embodiment, only the differences will be described here.

  Referring to FIG. 3 again, the transfer sheet 1 of the present invention includes a base sheet 2 having releasability, a metal thin film layer 3 formed over the entire surface of the base sheet 2 having releasability, and a transparent conductive material. The film layer 4 and the adhesive layer 5 may be provided.

  FIG. 4 is a view showing a transfer sheet according to the fourth embodiment of the present invention. Since the basic structure of the transfer sheet 1 in this embodiment is the same as that of the transfer sheet 1 according to the second embodiment, only the differences will be described here.

  Referring again to FIG. 4, the transfer sheet 1 of the present invention includes a base sheet 7, a release layer 6, a metal thin film layer 3 formed over the entire surface of the release layer 6, and a transparent conductive film layer 4. And an adhesive layer 5.

  Next, the manufacturing method of a transfer sheet is demonstrated. A transfer sheet provided with a partially formed transparent conductive film layer is produced by a manufacturing method including a step of partially forming a metal thin film layer and a subsequent step of forming a transparent conductive film layer. There are two embodiments of the manufacturing method. First, after describing the first embodiment, the second embodiment will be described.

  FIG. 5 shows a first embodiment of a transfer sheet manufacturing method according to the present invention. Referring to FIG. 5, in the first embodiment of the transfer sheet manufacturing method according to the present invention, a step of partially forming mask layer 8 on base sheet 2 having releasability, The step of forming the metal thin film layer 3 on the base sheet 2 having releasability, the mask layer 8, and the metal thin film layer 3 formed on the mask layer 8 are peeled and removed with a solvent to release A step of partially forming the metal thin film layer 3 on the base sheet 2 provided with a transparent material mainly composed of graphene on the metal thin film layer partially formed on the base sheet 2 having releasability Forming a conductive film layer 4.

  With reference to Fig.5 (a), in the 1st process of the manufacturing method of the transfer sheet which concerns on this invention, the mask layer 8 is partially formed on the base sheet 2 provided with the said mold release property.

[Mask layer]
The mask layer of the present invention is a layer soluble in a solvent. Examples of the material of the mask layer 8 include polyvinyl alcohol (PVA) and water-soluble acrylic resin. Examples of the solvent include an aqueous solution and an alcohol solution. Examples of the forming method include printing methods such as offset printing, screen printing, gravure printing, inkjet printing, and relief printing. Compared to the photoresist method described later, the number of steps is small.

  With reference to FIG.5 (b), the metal thin film layer 3 is formed on the base sheet 2 provided with the mask layer 8 and mold release property at a 2nd process. In the case of forming the metal thin film layer 3, the metal thin film layer 3 is formed on the entire surface of the base sheet 2 having releasability by sputtering, vapor deposition, ion plating, or the like.

  Referring to FIG. 5 (c), in the third step, the metal thin film layer 3 formed on the mask layer 8 is removed by solvent cleaning, and a part is formed on the base sheet 2 having the releasability. Thus, the metal thin film layer 3 is formed. As the solvent, aqueous solutions and alcohols are often used.

  With reference to FIG.5 (d), in the 4th process, the transparent conductive film layer 4 which has a graphene as a main component is formed on the metal thin film layer 3 partially formed on the base sheet 2 provided with a release property. Form. As a method of forming the transparent conductive film layer 4 containing graphene as a main component on the metal thin film layer 3, a chemical vapor deposition method (CVD method) is used. Among the chemical vapor deposition methods, a microwave plasma CVD method is used. It is preferable to use it.

  When microwave plasma CVD is used, the energy density distribution of the generated plasma can be controlled, and graphene can be deposited using microwave plasma under relatively low pressure and low temperature conditions. Damage to the base sheet 2 having releasability for supporting the layer 4 can be reduced. Furthermore, since the opposite side of the base sheet 2 having releasability from the side on which the graphene film is formed is cooled, the damage to the base sheet 2 having releasability can also be reduced. Thus, since the transparent conductive film layer 4 can be formed on the base sheet 2 having releasability through the metal thin film layer 3 under relatively low temperature conditions, the base sheet 2 having releasability is flexible. A characteristic film can be used. As a result, a roll-to-roll method can be adopted in forming the transparent conductive film layer 4 and all steps for producing a transfer sheet can be made a roll-to-roll method. Productivity is dramatically improved.

  The source gas for microwave plasma CVD is a mixed gas of hydrocarbon and rare gas, and examples of the hydrocarbon include methane (CH4), ethane (C2H6), propane (C3H8), and acetylene (C2H2). Examples of the rare gas include helium (He), neon (Ne), and argon (Ar). In a state where the chamber of the CVD apparatus is decompressed, the total pressure of the mixed gas in the apparatus is set to 10 to 400 Pa. When the total pressure by the mixed gas in the apparatus is less than 10 Pa, the reaction is difficult to proceed, and conversely, when the total pressure by the mixed gas in the apparatus is higher than 400 Pa, the temperature in the chamber becomes high. . A small amount of hydrogen gas may be mixed with this mixed gas. Further, as described above, since the distribution of the plasma energy density can be controlled, the total pressure due to the mixed gas in the apparatus can be kept relatively low by appropriately setting the energy density only in the necessary space. Thereby, the temperature in the chamber can also be suppressed to a relatively low level, and heating of the transfer sheet to be manufactured can be suppressed. The temperature in the chamber of the CVD apparatus is 200 to 400 ° C. When the temperature in the chamber is lower than 200 ° C., there arises a problem that the crystallinity of the generated graphene is lowered. On the other hand, when the temperature in the chamber is higher than 400 ° C., there is a problem that the base sheet expands and contracts due to the high temperature.

  A transfer sheet can be obtained through the steps from the first step to the fourth step. Also, through the above steps, a transparent conductive film mainly composed of graphene patterned on a transfer sheet can be directly formed. Therefore, a patterning step by oxidation etching or electron beam after graphene film formation Without going through. Furthermore, since the transparent conductive film layer mainly composed of graphene is formed on the transfer sheet, the transparent conductive film can be formed on the desired transfer target material very easily by transfer. Thus, the metal substrate after the graphene generation is not dissolved or transferred to another substrate. From the above, the generated graphene can be formed on the substrate sheet and the transfer target without being damaged more than necessary.

  If necessary, the adhesive layer 5 may be formed on the entire surface including the transparent conductive film layer 4 after the fourth step. The material and forming method of the adhesive layer 5 are as described above.

  In addition, you may form the release layer 6 on a base sheet before a 1st process as needed. The material and forming method of the release layer 6 are as described above.

  FIG. 6 shows a second embodiment of the transfer sheet manufacturing method according to the present invention. Since the basic configuration of the transfer sheet manufacturing method according to this embodiment is the same as that according to the transfer sheet manufacturing method according to the first embodiment, only differences will be described here.

  Referring to FIG. 6, the second embodiment of the transfer sheet manufacturing method according to the present invention includes a step of forming metal thin film layer 3 on the entire surface of base sheet 2 having releasability, and a metal thin film layer. A step of forming a portion where the resist layer 9 is formed on the metal thin film layer 3, a portion where the resist layer is not formed, and a portion where the resist layer 9 is not formed. The process of forming the metal thin film layer 3 and the resist layer 9 on the base sheet 2 having releasability by peeling and removing the metal thin film layer 3 with a solvent, and removing the resist layer 9 using the solvent And a step of exposing the metal thin film layer 3 to the surface and a step of forming the transparent conductive film layer 4 mainly composed of graphene on the metal thin film layer 3 exposed on the surface.

  With reference to Fig.6 (a), in the 1st process of the manufacturing method of the transfer sheet which concerns on this invention, the metal thin film layer 3 is formed on the base sheet 2 provided with the said release property.

[Resist layer]
With reference to FIG. 6B, in the second step, a resist layer 9 is partially formed on the metal thin film layer 3, and the resist layer 9 of the metal thin film layer 3 is formed. A portion where no is formed is formed. As the material of the resist layer 9, a resin that can be used as a photoresist, such as a novolac resin, can be used.

  As a method for forming the resist layer 9, a photoresist method is generally employed. Compared with the method of directly patterning the mask layer shown in FIG. 5 by a printing method, since light is used, there is a feature that more precise patterning is possible. First, the entire surface is formed by a printing method such as screen printing, gravure printing, ink jet printing, letterpress printing, or the resist film having the resist layer is heated and pressed on the metal thin film layer 3 formed on the entire surface of the base sheet. It is formed by bonding. After the resist layer 9 is formed by the above-described method, the resist layer 9 is irradiated with light and subjected to an exposure process in which the irradiated portion is reactively cured, followed by a development process in which the portion not irradiated with light is removed. Is partially formed. The resist layer 9 is a negative type (when exposed, the solubility in the developer is lowered and the exposed portion remains after development). However, the resist layer 9 is positive type (with respect to the developer when exposed to light). The solubility may be increased and the exposed portion may be removed after development).

  Referring to FIG. 6C, the metal thin film layer 3 where the resist layer 9 is not formed in the third step is removed by etching with an acid or alkali aqueous solution, etc. The metal thin film layer 3 and the resist layer 9 are partially formed. As the acid, hydrochloric acid, sulfuric acid, nitric acid and the like are used, and as the aqueous alkali solution, a sodium hydroxide aqueous solution and the like are preferably used.

  Referring to FIG. 6D, in the fourth step, the resist layer 9 is removed using a solvent to expose the metal thin film layer 3 on the surface. As a solvent for removing the resist layer 9, in the case of a positive type, an aqueous solution of an organic quaternary base that is a strong alkali can be used. Examples of the organic quaternary base include tetramethylammonium hydroxide and tetrabutylammonium hydroxide.

  By performing the steps from the first step to the fourth step, fine patterning is possible as compared with the case where the metal thin film layer 3 is patterned with the mask layer 8.

  FIG. 7 is a view showing the transparent conductive material 11 manufactured using the transfer sheet according to the first and second embodiments of the present invention. Referring to FIG. 7, the transparent conductive material 11 of the present invention is composed of a transferred object 10, an adhesive layer 5 and a transparent conductive film layer 4 formed on the transferred object 10.

[Transfer]
The transfer target 10 is not particularly limited as long as it is transparent, does not have electrical conductivity, and has a certain degree of hardness, and may be a molded product having a three-dimensional shape in addition to a film shape. Examples of the material of the transfer target 10 include glass, polyethylene terephthalate (PET), polyethylene, polypropylene, polystyrene, polyester, polycarbonate (PC), polyvinyl chloride, and acrylic. The thickness of the film-shaped transfer target 9 is preferably 30 to 200 μm.

  FIG. 8 is a diagram showing a method for producing a transparent conductor. Referring to FIGS. 8A to 8C, the transparent conductive material 11 is formed by transferring the transparent conductive film layer 4 and the metal thin film layer 3 of the transfer sheet 1 of the present invention 10 via an adhesive layer. After the transfer, the metal thin film layer 3 alone is removed from the transfer target 10. That is, after the transfer sheet 1 of the present invention and the transfer target 10 are integrated under conditions such as pressure or heating, the base sheet 2 having releasability is peeled off from the transfer target 10 and the metal thin film layer 3 Can be obtained by etching away.

Example 1
A mask layer was partially formed by an offset printing method using a polyvinyl alcohol resin on a base sheet made of a polyimide film with a thickness of 30 μm having a surface arithmetic average roughness (Ra) of 0.4 nm. After the mask layer was dried, a metal thin film layer (Cu layer having a thickness of 100 nm) was formed on the base sheet and the mask layer by sputtering. Thereafter, the mask layer and the metal thin film layer formed on the mask layer were removed by washing with water to obtain a partially formed metal thin film layer. And the obtained sheet | seat is installed in a chamber, The said gas in the chamber so that the pressure of the raw material gas (partial pressure ratio methane: argon = 1: 1) which consists of methane and argon in a chamber may become fixed (360 Pa). The inflow speed of the source gas and the exhaust speed by the pump were adjusted. In this state, a transparent conductive film layer containing graphene as a main component was formed by microwave plasma CVD under conditions of 380 ° C. and 40 seconds. Finally, an adhesive layer was formed on the entire surface of the transparent conductive film layer to obtain a transfer sheet.
Example 2
A transfer sheet was obtained in the same manner as in Example 1 except that a base sheet having a surface arithmetic average roughness (Ra) of 17 nm was used.
Example 3
A transfer sheet was obtained in the same manner as in Example 1 except that the thickness of the metal thin film layer was 0.02 μm.
Example 4
A transfer sheet was obtained in the same manner as in Example 1 except that the thickness of the metal thin film layer was 0.8 μm.
Example 5
Before forming a mask layer on a substrate sheet made of a polyimide film with a thickness of 30 μm, a fluororesin is used on the substrate sheet, and a release layer having a surface arithmetic average roughness (Ra) of 0.2 nm is formed. A transfer sheet was obtained in the same manner as in Example 1 except that it was formed.
Comparative Example 1
A transfer sheet was obtained in the same manner as in Example 1 except that a base sheet having a surface arithmetic average roughness (Ra) of 0.08 nm was used.
Comparative Example 2
A transfer sheet was obtained in the same manner as in Example 1 except that a base sheet having a surface arithmetic average roughness (Ra) of 22 nm was used.
Comparative Example 3
A transfer sheet was obtained in the same manner as in Example 1 except that the thickness of the metal thin film layer was 0.007 μm.
Comparative Example 4
A transfer sheet was obtained in the same manner as in Example 1 except that the arithmetic average roughness of the surface was 20 nm and the thickness of the metal thin film layer was 1.3 μm.
Comparative Example 5
A transfer sheet was obtained in the same manner as in Example 5 except that the arithmetic average roughness (Ra) of the surface of the release layer was 0.08 nm.

  After the transfer sheets obtained in Examples 1 to 5 and Comparative Examples 1 to 5 were attached to polyethylene terephthalate, the base sheet or the base sheet and the release layer were peeled from the transfer target. And the amount of the residue adhering on a base sheet or a mold release layer was compared and examined. Then, only the metal thin film layer formed on the surface of the transferred object was removed by the etching solution, and transparent conductive materials 1 to 5 including the transferred object and the transparent conductive film layer were obtained. The same operation was similarly performed on the transfer sheets obtained in Comparative Examples 1 to 5, and transparent conductors 6 to 10 were obtained.

Measurement of surface roughness of base sheet or release layer The surface roughness of the base sheet or release layer was measured by a method according to (JIS) B0601-1994, using Kosaka Laboratory Ltd. F3500D.

Evaluation of Transfer Sheet After the transfer sheets obtained in Examples 1 to 5 were adhered to polyethylene terephthalate as a transfer target, the base sheet or the base sheet and the release layer were peeled from the transfer target, and the base sheet Or the quantity of the residue adhering on a mold release layer was measured. As a result, except for the case where the transfer sheets of Comparative Examples 1 and 5 were used, the residue could hardly be observed with the naked eye. When the transfer sheets of Comparative Examples 1 and 5 were used, the presence of the residue could be found unlike the case of using other transfer sheets.

Evaluation of transparent conductor About the transparent conductors 1-10, the dispersion | variation degree of electroconductivity was evaluated. The evaluation method measured the resistance between the terminals of the same shape 10 times in the patterned transparent conductive film layer, and calculated the average value and the standard deviation of the obtained resistance values. As a result, the average value of the resistance values of the transparent conductors 1 to 5 was smaller than that of the transparent conductors 6 to 10. The standard deviation of the resistance value was smaller for the transparent conductors 1 to 5 than for the transparent conductors 6 to 10. From this, it was found that the transparent conductors 1 to 5 showed smaller and stable resistance values. As mentioned above, it turned out that the transparent conductors 1-5 obtained using the transfer sheet of Examples 1-5 have favorable electroconductivity.

DESCRIPTION OF SYMBOLS 1 Transfer sheet 2 Base sheet provided with releasability 3 Metal thin film layer 4 Transparent conductive film layer 5 Adhesive layer 6 Release layer 7 Base sheet 8 Mask layer 9 Resist layer 10 Transfer object 11 Transparent conductor

Claims (6)

A base sheet having releasability and smoothness;
A metal thin film layer partially or entirely formed on the base sheet so as to reflect the smoothness of the base sheet;
A transparent conductive film layer mainly formed of graphene formed on the metal thin film layer;
Equipped with a,
The arithmetic mean roughness (Ra) of the substrate sheet surface is 20 nm or less,
A transfer sheet in which the metal thin film layer has a thickness of 0.01 to 1 μm . The transfer sheet according to claim 1, further comprising a release layer on the base sheet. Transfer sheet according to any one of claims 1-2 comprising an adhesive layer on the transparent conductive film layer. Partially forming a metal thin film layer on the substrate sheet;
Forming a transparent conductive film layer mainly composed of graphene on the metal thin film layer partially formed on the base sheet;
With
The arithmetic mean roughness (Ra) of the substrate sheet surface is 20 nm or less,
The manufacturing method of the transfer sheet whose thickness of the said metal thin film layer is 0.01-1 micrometer . Forming the metal thin film layer partially,
Partially forming a mask layer on the substrate sheet;
Forming the metal thin film layer on a base sheet having the mask layer and the releasability;
Peeling off the metal thin film layer formed on the mask layer and the mask layer with a solvent, and forming the metal thin film layer partially on the base sheet;
The manufacturing method of the transfer sheet of Claim 4 provided with these. Forming the metal thin film layer partially,
Forming the metal thin film layer on the base sheet;
Forming a resist layer partially on the metal thin film layer, forming a location where the resist layer is formed on the metal thin film layer, and forming a location where the resist layer is not formed;
Peeling and removing the metal thin film layer where the resist layer is not formed with a solvent, and partially forming the metal thin film layer and the resist layer on the base sheet;
Removing the resist layer using a solvent and exposing the metal thin film layer to the surface;
The manufacturing method of the transfer sheet of Claim 4 provided with these.

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