TWI640035B - Method of forming conductive pattern, on-cell type touch panel using the same, and transfer film used therein and on-cell type touch panel - Google Patents

Abstract

An object of the invention is to provide a conductive pattern forming method which can be easily applied to a liquid crystal display element and other elements, and a transfer film used therefor.

The solution of the present invention is to form an adhesive layer (12) on one of the main faces of the support film (10), and apply a conductive ink containing a metal nanowire and/or a metal nanotube to the adhesive layer (12). A specific pattern forms a conductive preparation layer (14). This pattern is also included in the overall coating of the adhesive layer (12) in a comprehensive shape. The conductive preliminary layer (14) is irradiated with pulsed light to exhibit or improve conductivity, and is converted into a conductive layer (16). A protective film (18) is formed on the conductive layer (16) as necessary to obtain a film for transfer. The support film (10) is peeled off, and the conductive layer (16) is attached to the substrate (20) through the adhesive layer (12). When a transfer film having a protective layer (18) is used, the protective layer (18) is removed and the conductive layer (16) is exposed, and it is necessary to process the conductive layer (16) formed into a comprehensive shape by etching or the like to be specific. picture of.

Description

Conductive pattern forming method and manufacturing method using the same on-cell type touch panel, and transfer film and on-cell type touch panel used in the same

The present invention relates to a method of forming a conductive pattern and a method of manufacturing the same using the on-cell type touch panel, and a film for transfer and an on-cell type touch panel.

A transparent electrode that can transmit light is an essential constituent member for a driving electrode of a liquid crystal display element constituting a liquid crystal display, an organic EL (electroluminescence) element, a solar cell element, a touch panel, or the like.

For the transparent conductive film used for these transparent electrodes, ITO (Indium Tin Oxide) has been used until now. However, since indium used for ITO is a rare metal, the supply and price stabilization have become important issues in recent years. Further, in the film formation of ITO, a sputtering method, a vapor deposition method, or the like is used. Therefore, a vacuum manufacturing apparatus is required, and the cost is high in addition to the long manufacturing time. Furthermore, ITO can be cracked easily due to physical stress such as bending. It is damaged, so it is difficult to apply it to a substrate that imparts flexibility. Therefore, the exploration of ITO alternative materials to solve these problems continues.

Therefore, among the "ITO substitute materials", as a material which can be coated and formed without using a vacuum manufacturing apparatus, for example, (i) poly(3,4-ethylenedioxythiophene)/poly (i) has been reported. a polymer-based conductive material such as 4-pyrenesulfonic acid) (PEDOT: PSS) (for example, refer to Patent Document 1), and (ii) a conductive material containing a metal nanowire (see, for example, Patent Document 2 and Non-Patent Document 1) And (iii) a conductive material containing a conductive component of a nanostructure, such as a conductive material containing a carbon nanotube (for example, refer to Patent Document 3).

Among them, the conductive material containing the metal nanowire (ii) has been reported to exhibit low surface resistance and high light transmittance (see, for example, Patent Document 2 and Non-Patent Document 1), and further has flexibility, so it is suitable as "ITO replacement materials". In the case of a metal nanowire, in order to exhibit electrical conductivity or to improve conductivity, there is a method of heating at a high temperature (200 ° C or higher), but a conductive film is formed on a resin film lacking heat resistance or It is difficult to form an inexpensive conductive film by lowering the temperature (for example, see Patent Document 4). Therefore, a method of exhibiting light conductivity by light irradiation has been disclosed (for example, refer to Patent Document 5).

Here, for example, in the touch panel, as described in the following Non-Patent Document 2, there are an exterior type and a built-in type, and the on-cell type and the in-cell type can be distinguished in the built-in type. Among these, the touch panel of the built-in type (especially the on-cell type) first forms a liquid crystal display element and then forms a transparent electrode of the touch panel using a conductive material containing the metal nanowire.

On the other hand, in order to exhibit or improve conductivity, the conductive material containing the metal nanowire needs to be subjected to light irradiation or high-temperature (200 ° C or higher) heat treatment or pressurization as described above, but is contained therein. When the liquid crystal of the liquid crystal display element is irradiated with light or heated at a high temperature (200 ° C or higher), it may be affected by liquid crystal decomposition or changes in TFT characteristics. Therefore, it is preferable that the liquid crystal display element and the touch are formed. The substrate of the panel is subjected to direct light irradiation. Further, it is not easy to pressurize the surface of such a member, and it is difficult to impart conductivity to the member without affecting the member.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 4076775

[Patent Document 2] Japanese Patent Publication No. 2009-505358

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2003-100147

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2004-273205

[Patent Document 5] International Publication No. 2013/133420

[Non-patent literature]

Non-Patent Document 1: Shih-Hsiang Lai, Chun-Yao Ou, Chia-Hao Tsai, Bor-Chuan Chuang, Ming-Ying Ma, and Shuo-Wei Liang; SID Symposium Digest of Technical Papers, Vol.39, Issue 1, Pp. 1200-1202 (2008)

Non-Patent Document 2: Feeding Yu Hong "Introduction to Flat Panel Display (6) Component/Material Technology for Supporting FPD (1) Touch Panel" THE CHEMICAL TIMES 2011 No. 4 (Vol. 222) 2-7

An object of the present invention is to provide a method for forming a conductive pattern on a substrate that cannot be subjected to direct light irradiation or high-temperature heat treatment or pressure treatment, such as an on-cell type touch panel, and the manufacture of an on-cell type touch panel using the same. The method, and the transfer film and the on-cell type touch panel used for the same.

In order to achieve the above object, an embodiment of the present invention is a method of forming a conductive pattern, comprising: providing a support film, an adhesive layer formed on the support film, and a specific layer formed on the adhesive layer a step of patterning the transfer film including the conductive layer of the metal nanowire and/or the metal nanotube, peeling off the support film of the transfer film, and then adhering the conductive layer to the substrate through the adhesive layer .

Further, in the above-described conductive pattern forming method, preferably, in the step of preparing the transfer film, a conductive ink containing a metal nanowire and/or a metal nanotube is coated on a subsequent layer to a specific pattern shape. And forming a conductive preliminary layer, and forming a conductive material comprising a metal nanowire and/or a metal nanotube by irradiating the conductive preliminary layer with pulsed light The steps of the layer.

Further, in the conductive pattern forming method, the step of preparing the transfer film may be performed by coating a conductive ink containing a metal nanowire and/or a metal nanotube on a bonding layer to form a conductive layer. a step of preparing a layer, and a step of forming a conductive layer comprising a metal nanowire and/or a metal nanotube by irradiating the conductive preliminary layer with pulsed light, and a pattern processing step of processing the conductive layer into a specific pattern.

Further, the step of preparing the film for transfer may have a step of forming a protective layer on the main surface opposite to the main surface of the conductive layer including the adhesive layer, and removing the protective layer after the subsequent step. .

Further, another embodiment of the present invention is a conductive pattern forming method characterized by having a conductive layer prepared to have a metal nanowire and/or a metal nanotube having a specific pattern shape on a support film, and The step of transferring the film of the adhesive layer formed on the conductive layer, the subsequent step of attaching the adhesive layer of the transfer film to the substrate, and the step of removing the support film.

Further, another embodiment of the present invention is a method of manufacturing an on-cell type touch panel, characterized in that in the method of forming a conductive pattern, the substrate is a transparent substrate of liquid crystal in which a liquid crystal display element is sealed, and the adhesive layer is Next, the surface of the transparent substrate opposite to the side on which the liquid crystal side is sealed is formed.

Further, another embodiment of the present invention is a film for transfer characterized by sequentially laminating a support film, an adhesive layer, and comprising A specific pattern of metal nanowires and/or a conductive layer of a metal nanotube.

Preferably, at least a portion of the intersection of the metal nanowires and/or the metal nanotubes constituting the conductive layer is preferably followed.

Further, a protective layer may be provided on the main surface of the conductive layer opposite to the main surface on which the adhesive layer is provided.

Further, another embodiment of the present invention is an on-cell type touch panel, characterized in that the transfer film is bonded to a surface of the liquid crystal display substrate on which the liquid crystal is sealed on the opposite side of the liquid crystal side. .

According to the present invention, a conductive pattern manufacturing method which can be easily applied to liquid crystal display elements and other elements, and a transfer film used therefor can be realized.

10‧‧‧Support film

12‧‧‧Next layer

14‧‧‧ Conductive preparation layer

16‧‧‧ Conductive layer

18‧‧‧Protective layer

20‧‧‧Substrate

22‧‧‧Transfer film

24‧‧‧Stainless steel plate

26‧‧‧Color filter substrate

28‧‧‧Array substrate

30‧‧‧Liquid layer

32‧‧‧TFT (thin film transistor)

34‧‧‧on-cell type touch panel transparent electrode

36, 38‧‧‧ polarizing plate

Fig. 1 is a cross-sectional view showing an example of a procedure relating to a method of manufacturing a conductive pattern of an embodiment.

Figure 2 is a diagram for explaining the definition of pulsed light.

Fig. 3 is a view showing an SEM image of a silver nanowire prepared in the examples.

Fig. 4 is a view for explaining a method of irradiating light to the film for transfer of Example 3.

FIG. 5 is an on-state of a conductive layer formed as a transparent electrode for an on-cell type touch panel by a conductive pattern forming method related to an embodiment. An example of a cell type touch panel.

Hereinafter, the form for carrying out the invention (hereinafter referred to as an embodiment) will be described with reference to the drawings.

1(a) to 1(h) are cross-sectional views showing a procedure example of a method of forming a conductive pattern according to one embodiment of the present embodiment, and the same constituent elements are denoted by the same reference numerals.

On one main surface of the support film 10 shown in Fig. 1(a), an adhesive layer 12 is formed as shown in Fig. 1(b) (the subsequent layer forming step). Examples of the method for forming the adhesive layer 12 include application by a die coater or a gravure coater, or screen printing, gravure lithography, or adhesion of a film, but are not limited thereto. Thereafter, a conductive ink containing a metal nanowire and/or a metal nanotube is applied to the specific layer (coating step) on the adhesive layer 12 to form a conductive preliminary layer 14 (Fig. 1(c)). In this case, as a pattern, the entire surface of the adhesive layer 12 is completely formed in addition to the pattern such as an electrode. The term "coating" as used in this specification includes printing. In addition, "comprehensive" means that it is fully applied in a certain area.

Next, by irradiating the conductive preparation layer 14 (the metal nanowire and/or the metal nanotube) with pulsed light, firing the metal nanowire and/or the metal nanotube (making the metal nanowire and / or the metal nanotubes are fused to each other at the peripheral intersection portion thereof to make the conductive preparation layer 14 exhibit conductivity, or to improve the conductivity of the conductive preparation layer 14 to convert the conductive preparation layer 14 into a conductive layer 16 (light irradiation step, Fig. 1 (d)). Thereafter, a protective layer 18 is formed on the conductive layer 16 as necessary (protective layer forming step, FIG. 1(e)). By the above steps, the transfer film in which the support film 10, the adhesive layer 12, the conductive layer 16, and the protective layer 18 are sequentially laminated is formed.

Next, the support film 10 is peeled off, and the conductive layer 16 is then passed through the subsequent layer 12 to the substrate 20 (following step, Fig. 1 (f)). The substrate 20 may be, for example, an array substrate in which liquid crystal is sandwiched between liquid crystal display elements and a color filter substrate (see FIG. 5). Further, the substrate 20 may be carried out, for example, by using a laminating device, a laminator, or the like. Thereby, the conductive layer 16 is transferred to the substrate 20, and a conductive pattern can be provided on the substrate 20. When a film having the protective layer 18 is used as the transfer film, the protective layer 18 on the conductive layer 16 is removed (Fig. 1 (g), and the conductive layer 16 is exposed (protective layer removing step).

Next, in the case where a transparent electrode of the touch panel is formed, the conductive layer 16 is processed into a specific pattern such as a transparent electrode by etching treatment such as photolithography (pattern processing step, FIG. 1(h)). When a silver nanowire and/or a metal nanotube is used as an example of the metal nanowire and/or the metal nanotube, for example, a Pure Etch GNW Series manufactured by Ivy Pure Chemical Industries, Ltd., or the like can be used. Further, when the conductive layer is used as a transfer film which is previously processed into a pattern shape, a pattern processing step is not required. Further, a conductive pattern having a conductive portion and a non-conductive portion can be formed by irradiating pulsed light through a transmission mask pattern exemplified in Examples to be described later.

Further, after the light irradiation step, a transparent conductive polymer layer may be formed on the conductive layer 16. Further, the step is formed by the subsequent layer In the case of the transfer film produced in the protective layer forming step, in consideration of the mass productivity at the time of use, it is assumed that a cylindrical core such as a resin is used as a shaft and is in the form of a roll. In addition, it may be a pattern that is cut into a sheet shape. There is no particular limitation on the type.

Further, the steps of FIGS. 1(a) to 1(g) may be changed in order. For example, the conductive preliminary layer 14 is formed in a desired pattern on one of the main faces of the support film 10 shown in FIG. 1(a) (in the state in which the layer 12 is not provided in FIG. 1(c)), and pulsed light is irradiated thereto. The conductive preparation layer 14 exhibits electrical conductivity or enhances the conductivity of the conductive preparation layer 14 to convert the conductive preparation layer 14 into the conductive layer 16 (in the state in which the layer 12 is not attached in FIG. 1(d)), secondarily on the conductive layer 16. The adhesive layer 12 is formed, and the support layer 10 and the conductive layer 16 formed on the support film 10 are bonded to the substrate 20 via the adhesive layer 12. Thereafter, the support film 10 is removed to be in the state of Fig. 1(g). In this case, the smoothness of the surface (the surface opposite to the substrate 20) transferred to the conductive layer 16 of the substrate 20 can be improved.

FIG. 5 shows an example of an on-cell type touch panel in which a conductive layer 16 as a transparent electrode for an on-cell type touch panel is formed by the above-described conductive pattern forming method. In the example of FIG. 5, a liquid crystal display element is formed between the glass substrate (the color filter substrate 26 and the array substrate 28) as a transparent substrate, and the liquid crystal layer 30 and the TFT (thin film transistor) 32 are formed. Further, the liquid crystal layer 30 is sealed between the color filter substrate 26 and the array substrate 28 by a sealant (not shown). In FIG. 5, the transparent electrode (conductive layer 16) of the transparent electrode 34 for the on-cell type touch panel is transmitted through a conductive pattern forming method according to the present embodiment. The adhesive layer 12 is then applied to the color filter substrate 26 to form an on-cell type touch panel. In this case, the conductive layer 16 is adhered to the surface of the color filter substrate 26 opposite to the side on which the liquid crystal layer 30 is sealed. Further, the polarizing plates 36 and 38 necessary for the liquid crystal display element of the on-cell type touch panel are formed outside the array substrate 28 and the on-cell type touch panel transparent electrode 34, respectively.

As the support film 10, chemical stability, heat stability, and formation into a film, a sheet, or a plate shape can be used. In addition, it also includes a mold release process for imparting peelability to the surface. Specific examples thereof include polyolefins such as polyethylene and polypropylene, polyhalogenated vinyls such as polyvinyl chloride and polydichloroethylene, and cellulose derivatives such as cellulose acetate, nitrocellulose, and cellophane. , polyamine, polystyrene, polycarbonate, polyimine, polyester. Among these, a two-axis extended polyethylene terephthalate film which is excellent in dimensional stability and which is permeable to light when irradiated with light is a two-axis stretch polyethylene terephthalate film.

The function of the above-mentioned adhesive layer 12 is to ensure the adhesion of the conductive layer 16 to the substrate 20 (the transferred body). Further, the purpose of the transparent conductive polymer layer provided as necessary is to improve the surface smoothness without losing the conductivity of the conductive layer 16.

The film thickness of the layer 12 and the transparent conductive polymer layer is preferably 0.1 to 50 μm, more preferably 0.3 to 30 μm, and particularly preferably 0.5 to 10 μm. If the film thickness is too thick, it cannot correspond to the thinning of the device. Further, since the transparent conductive polymer layer is colored by the conductive polymer itself, the film thickness is too thick, and the light transmittance is lowered. Then the layer 12 is too thin, and the substrate The adhesion of 20 (the transferred body) is insufficient, and when the conductive polymer is too thin, the effect of smoothing the surface cannot be exhibited.

Examples of the adhesion layer 12 include an acrylic resin, a styrene resin, an epoxy resin, a guanamine resin, a guanamine epoxy resin, an alkyd resin, a phenol resin, an ester resin, a urethane resin, and an epoxy resin. Polycondensation of an epoxy acrylate resin, a vinyl acetate resin, a partially alkalized vinyl acetate resin, a poval resin, a butyral resin obtained by reacting with a (meth)acrylic resin Acetal resin and the like. These resins may be used alone or in combination of two or more. Here, the "acrylic resin" means a polymer mainly having a monomer unit derived from a polymerizable unitary body having a (meth) acrylonitrile group. Moreover, "(meth)acryl fluorenyl" means an acryl fluorenyl group and a methacryl fluorenyl group. Similarly, "(meth)acrylyl" means a propylene group and a methacryl group.

The acrylic resin can be produced by radically polymerizing a polymerizable unit having a (meth)acryl fluorenyl group. These acrylic resins may be used alone or in combination of two or more.

Examples of the polymerizable mono-weight having a (meth) acrylonitrile group include acrylamide such as diacetone acrylamide, alkyl (meth) acrylate, and tetrahydro fluorenyl (meth) acrylate. Ester, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, glycidyl (meth)acrylate, 2,2,2-trifluoro(meth)acrylate Ethyl ester, 2,2,3,3-tetrafluoropropyl (meth)acrylate, and the like.

Further, the aforementioned acrylic resin may be in the form of a polymerizable monomer having a (meth)acryl fluorenyl group as described above. a polymerizable styrene derivative in which an α-position such as an olefin, a vinyl toluene or an α-methyl styrene or an aromatic ring is substituted, an ether of a vinyl alcohol such as acrylonitrile or vinyl-n-butyl ether; One type or two or more types of polymerizable units are copolymerized.

The weight average molecular weight of these resins is preferably from 3,000 to 1,000,000.

Further, the transparent conductive polymer layer is composed of a material containing a conductive polymer, and examples of the conductive polymer include polythiophene-based, polyacetylene-based, poly(para-phenylene), and PPP. A conductive polymer such as polyaniline, polyparaphenylene vinylene or polypyrrole. Among them, a conductive polymer having transparency is doped polystyrenesulfonic acid (PSS) and polyethylene. Sulfonic acid (PVS), or poly(3,4-ethylenedioxythiophene) (PEDOT) of p-toluenesulfonic acid (TSO), also known as PEDOT/PSS, PEDOT/PVS, PEDOT/TSO, etc. .

As the polythiophene-based conductive polymer, for example, an undoped polymer having a main chain composed of a polythiophene-based polymer represented by the following chemical formula, and a halogen or other oxidizing agent such as iodine may be used. The polymer is partially oxidized to form a cation structure.

In the above chemical formula, each of the R ¹ group and the R ² group may be independently selected from each other, and as an option, a hydrogen atom; a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom or an iodine atom; a cyano group; a methyl group; an ethyl group; a straight-chain alkyl group such as propyl, butyl (n-butyl), pentyl (n-pentyl), hexyl, octyl, dodecyl, hexadecanyl, octadecyl; isopropyl, isobutyl , sec-butyl, tert-butyl, isopentyl, neopentyl and the like having an alkyl group; methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy a straight or chain alkoxy group such as a sec-butoxy group or a tert-butoxy group; an alkenyl group such as a vinyl group, a propenyl group, an allyl group, a butenyl group or an oleyl group; an ethynyl group; Alkynyl, butynyl and the like alkynyl; methoxymethyl, 2-methoxyethyl, 2-ethoxyethyl, 3-ethoxypropyl, etc. alkoxyalkyl; C ₂ H ₅ Polyethers such as O(CH ₂ CH ₂ O) _m CH ₂ CH ₂ group (m is an integer of 1 or more) and CH ₃ O(CH ₂ CH ₂ O) _m CH ₂ CH ₂ group (m is an integer of 1 or more) A fluoromethyl group or the like, a halogen-substituted derivative such as fluorine of the above-mentioned substituent, or the like.

Among the polythiophene-based conductive polymers, 3,4-ethylenedioxythiophene (PEDOT) is preferred. In particular, PEDOT-PSS in which PEDOT is doped with polystyrenesulfonic acid (PSS) is preferred because of its high transparency and low electrical resistance.

As a commercial item, Baytron (registered trademark) P manufactured by HC Starck Co., Ltd. and Clevios (registered trademark) SV3 manufactured by Heraeus Co., Ltd., or Denatron (registered trademark) #5002LA manufactured by Nagase ChemteX Co., Ltd., or Orgacon manufactured by Agfa-Gevaert Co., Ltd. Registered trademark) S300 or Orgacon3040.

The metal nanowire and/or the metal nanotube are dispersed in a solution (dispersion medium) containing a thermosetting or thermoplastic binder resin having no fluidity in the range of 5 to 40 ° C as a conductive ink. The conductive ink is patterned into a specific shape on the adhesive layer 12 formed on the surface of the support film 10 by gravure printing, screen printing, gravure lithography, letterpress printing, or the like to form the conductive preliminary layer 14. Further, in the pattern printing, a comprehensive overall coating (forming a full pattern) to the adhesive layer 12 is included. Further, the above-mentioned 5 to 40 ° C means a room temperature at which printing is normally performed.

Further, as described above, the conductive preliminary layer 14 is converted into the conductive layer 16 by the irradiation of the pulsed light. At this time, the outer peripheral portion of the intersection of the metal nanowire and/or the metal nanotube is fused to form a transparent conductive layer 16 having conductivity.

The thermosetting or thermoplastic binder resin which does not have fluidity in the range of 5 to 40 ° C, as long as it is a transparent resin, is itself It is not particularly limited as long as it has no fluidity at room temperature and is dissolved in a solvent. However, it is preferably used because it has high heat resistance and low hygroscopicity. Here, the "thermosetting resin" means a substance which is dissolved in a solvent in an unhardened state. The thermosetting resin is preferably thermally cured by light irradiation described later. Examples of the binder resin include acrylic resin, epoxy resin, epoxy acrylate resin, urethane acrylate resin, unsaturated polyester resin, allyl ester resin, diallyl phthalate ( DAP) resin, urethane resin, polyoxyn epoxide resin, polyester resin, polycarbonate resin, polyamide resin (nylon), amorphous polyolefin resin, polystyrene, polyvinyl acetate, poly N - Vinyl decylamine, poly-4-methylpentene-1, and the like. Among them, in particular, those having excellent affinity with silver include poly N-vinyl pyrrolidone, poly N-vinyl caprolactam, poly N-vinylacetamide, poly N-vinylformamide Iso-N-vinylamine, epoxy resin, urethane acrylate resin, urethane resin or cycloolefin polymer (COP, Cyclic Olefin Polymer), cyclic olefin copolymer (COC, Cyclic) An insulating resin such as Olefin Copolymer), but a known conductive resin can be used as necessary.

In particular, poly N-vinyl decylamines such as poly N-vinylpyrrolidone, poly N-vinyl caprolactam, poly N-vinylacetamide, poly N-vinylformamide, and the like are also used. In the synthesis of the rice noodles, it can be added as a protective film material which is combined with the prevention of aggregation, so that it can be used in the production stage of the nanowire, and it is easy to manufacture, and the quality of the electrode can be improved. So better.

The aforementioned metal nanowire or metal nanotube refers to a metal having a diameter of a nanometer size, a metal nanowire being linear, and a metal. The nanotube is a conductive material having a porous or non-porous tubular shape. In the present specification, both "linear" and "tubular" are linear, but the former means that the center is not hollow, and the latter is hollow. The trait can be soft or straight. The metal nanowire or the metal nanotube may be used singly or in combination.

The metal species constituting the metal nanowire or the metal nanotube may be at least one selected from the group consisting of gold, silver, platinum, copper, nickel, iron, cobalt, zinc, ruthenium, rhodium, palladium, cadmium, osmium, and iridium. One or a combination of alloys of these metals and the like. In order to obtain a coating film having a low surface resistance and a high total light transmittance, it is preferred to contain at least one of gold, silver and copper. Since these metals have high conductivity, when a specific surface resistance is obtained, the density of the metal on the surface can be reduced, so that a high total light transmittance can be achieved.

Among these metals, at least one of gold or silver is more preferable. As a most suitable aspect, a silver nanowire can be cited.

It is preferable that the metal nanowires and/or the metal nanotubes constituting the conductive layer 16 have a certain distribution of the diameter, the major axis length, and the aspect ratio. This distribution is selected in such a manner as to increase the total light transmittance of the conductive pattern (transparent electrode) according to the present embodiment and reduce the surface resistance. Specifically, the average diameter of the metal nanowire and the metal nanotube is preferably 1 to 500 nm, more preferably 5 to 200 nm, more preferably 5 to 100 nm, and more preferably 10 to 80 nm. Further, the average length of the long axis of the metal nanowire and the metal nanotube is preferably 1 to 100 μm, more preferably 1 to 50 μm, further preferably 2 to 50 μm, and more preferably 5 to 30 μm. Metal nanowires and metal nanotubes, the average of the diameter and the length of the long axis satisfy the above range, and are long The average width ratio is preferably greater than 5, more preferably 10 or more, 100 or more, and more preferably 200 or more. Here, the aspect ratio is a value obtained by a/b when the average thickness of the diameter of the metal nanowire and the metal nanotube is approximately b, and the average length of the major axis is approximately a. A and b can be arbitrarily measured by a scanning electron microscope to determine the average value of 20 pieces.

As a manufacturing method of a metal nanowire, a well-known manufacturing method can be used. For example, a silver nanowire can be synthesized by reducing a silver nitrate in the presence of polyvinylpyrrolidone using a poly-ol method (see Chem. Mater., 2002, 14, 4736). Similarly, the gold nanowire can be synthesized by reducing the water of gold chloride in the presence of polyvinylpyrrolidone (refer to J. Am. Chem. Soc., 2007, 129, 1733). The technique for large-scale synthesis and purification of the silver nanowire and the golden nanowire is described in detail in International Publication WO2008/073143 and International Publication No. 2008/046058. A gold nanotube having a porous structure can be synthesized by reducing a gold chloride solution by using a silver nanowire as a mold. Here, the silver nanowire used in the mold is eluted into the solution by a redox reaction with gold chloride acid, and as a result, a gold nanotube having a porous structure can be formed. (Refer to J. Am. Chem. Soc., 2004, 126, 3892-3901).

The conductive ink for forming a conductive pattern to be applied to the embodiment of the present invention dissolves the thermosetting or thermoplastic binder resin having no fluidity in the range of 5 to 40 ° C (room temperature) in the solvent. It can be prepared by dispersing a metal nanowire and/or a metal nanotube therein. The solvent to be used herein may be any solvent which can be generally used for gravure printing, screen printing, gravure lithography, letterpress printing, etc., and may be omitted. Use it with special restrictions. In the case of gravure printing, a solvent having a relatively low boiling point is used, and in the case of screen printing, a solvent having a relatively high boiling point is used.

The solvent having a relatively low boiling point which can be used for gravure printing has a boiling point of 50 ° C or more and 200 ° C or less, preferably 150 ° C or less. For example, an aromatic hydrocarbon such as toluene or xylene, a ketone system such as acetone or methyl ethyl ketone, or acetic acid can be used. An ester such as ethyl ester or N-propyl acetate; an organic solvent such as an alcohol solvent such as isopropyl alcohol, n-propanol, 2-butanol, isobutanol or n-butanol.

The solvent having a relatively high boiling point which can be used for screen printing has a boiling point of 360° C. or lower and 120° C. or higher, preferably 150° C. or higher, and specific examples thereof include butyl carbitol acetate and diethyl phthalate. Alcohol butyl ether, terpineol, isodecyl cyclohexanol (trade name: Terusolve MTPH, manufactured by Japanese terpene), xylene, bis-ethoxyethane, ethylene glycol, propylene glycol Wait.

Further, these solvents may be used alone or in combination of two or more.

The content of the metal nanowire and/or the metal nanotube of the conductive ink according to the present embodiment is excellent in dispersibility and good pattern formation of the coating film obtained from the conductive ink, and high conductivity. From the viewpoint of properties and good optical properties, the metal nanowire and/or the metal nanotube of the total mass of the conductive ink is 0.01 to 10% by mass, more preferably 0.05 to 2% by mass. If the metal nanowire and/or the metal nanotube is less than 0.01% by mass, to ensure the desired conductivity, the transparent conductive film layer must be printed to be very thick, except that the printing difficulty becomes high, and the pattern is maintained when dry. It is difficult. In addition, if it exceeds 10% by mass, be sure to The transparency required must be printed to be very thin, and printing on this occasion becomes difficult.

Further, the amount of the thermosetting or thermoplastic binder resin which does not have fluidity at room temperature by adding the metal nanowire and/or the metal nanotube is different depending on the resin to be used. In general, the amount of the metal nanowire and/or the metal nanotube is 100 parts by mass to 2500 parts by mass, preferably 150 parts by mass to 2000 parts by mass. When the binder resin is 100 parts by mass or less, the surface smoothness is lowered. Further, when the amount of the pulsed light is more than 2,500 parts by mass, the surface resistance cannot be lowered.

The conductive ink to be applied to the present embodiment may contain any component other than the above components (metal nanowire, metal nanotube, or binder resin) in a range that does not impair the properties thereof, for example, improvement and basis. A wetting and dispersing agent, a surface conditioner, an antifoaming agent, a thixotropic agent, a leveling agent, an anticorrosive agent, a adhesion promoter, a surfactant, a rheology control agent, and the like.

Examples of the wetting and dispersing agent include DISPERBYK (registered trademark)-106, DISPERBYK (registered trademark)-108 (manufactured by BYK‧Japan), and surface modifiers include BYK (registered trademark)-300 and BYK ( Registered trademark) - 306 (manufactured by BYK ‧ Japan Co., Ltd.), and as a defoaming agent, BYK (registered trademark) -051, BYK (registered trademark) - 054 (manufactured by BYK‧ Japan), as a thixotropic The agent may be AEROSIL (registered trademark) 380, AEROSIL (registered trademark) R106, AEROSIL (registered trademark) R-812 (manufactured by Japan Aerosil Co., Ltd.), and leveling agent (leveling) Illustrative examples of the agent include BYKETOL (registered trademark)-OK (manufactured by BYK‧Japan), benzotriazole as the anticorrosive agent, and 2-hydroxymethylcellulose as the adhesion promoter. The surfactant is F-472SF (manufactured by DIC), and the rheology control agent is BYK (registered trademark)-405, BYK (registered trademark)-410, BYK (registered trademark)- 311 (made by BYK‧Japan).

The conductive ink according to the present embodiment can be produced by appropriately selecting, stirring, mixing, heating, cooling, dissolving, dispersing, or the like by a known method.

The preferred viscosity of the conductive ink according to this embodiment differs depending on the printing method, but in the case of gravure printing, the viscosity at 25 ° C is preferably from 50 to 10,000 mPa·s, more preferably from 300 to 5,000 mPa. s. In the case of screen printing, the viscosity at 25 ° C is preferably from 100 to 2 × 10 ⁵ mPa ‧ , more preferably from 1 × 10 ³ to 5 × 10 ⁴ mPa ‧ s. Further, the viscosity is a value measured by using a rotational viscosity agent. In the examples and comparative examples described later, Brookfield HBDV-II+Pro (plate type CP-40 (26 to 87, 200 mPa‧s at low viscosity) or CP-52 (800 to 2, 620,000 mPa at high viscosity) was used. s)).

The conductive ink prepared in this manner is subjected to pattern printing of a desired shape on the adhesive layer 12 by coating with a die coater or a gravure coater, or gravure printing, screen printing, ink jet printing, letterpress printing or the like. .

The amount of the conductive ink to be applied is determined in consideration of the thickness of the conductive layer 16 required for the application. The thickness of the conductive layer 16 can be adjusted by The coating amount of the conductive ink and the conditions of the coating method were adjusted. A preferred thickness is 60 nm to 3 μm.

The printed (coated) conductive ink is dried by heating the coated material as needed. The heating temperature varies depending on the liquid component constituting the dispersion medium, but if the drying temperature is too high, the formed pattern may not be maintained. Therefore, the drying temperature is also at most 120 ° C or lower, more preferably 100 ° C or lower. In particular, the initial drying temperature is important, and drying starts at 40 to 80 ° C, and it is particularly preferable to gradually increase the temperature in a range of not more than 120 ° C as necessary.

The surface resistance, the total light transmittance, and the haze value of the conductive layer 16 can be obtained by adjusting the film thickness, that is, the composition, the coating amount, the coating method, and the like of the conductive ink which is appropriately selected and used.

In general, the thicker the film thickness, the lower the surface resistance and total light transmittance. Further, the higher the concentration of the metal nanowire or the metal nanotube in the conductive ink, the lower the surface resistance and the total light transmittance, and the higher the haze.

As described above, the conductive preliminary layer 14 formed of the conductive ink is irradiated with the pulsed light to be converted into the conductive layer 16. However, the term "pulsed light" as used herein means that the light irradiation period (irradiation time) is short. When the light of time is repeatedly irradiated with light, as shown in FIG. 2, it means that there is a period of non-irradiation between the first light irradiation period (on) and the second light irradiation period (on) (irradiation interval ( Off)) The light is illuminated. In Fig. 2, the light intensity of the pulsed light is constant, but the light intensity may be changed during the primary light irradiation (on). The aforementioned pulse light is light that has a flash lamp such as a xenon flash lamp. Source to illuminate. Using such a light source, the metal nanowires and/or the metal nanotubes of the conductive preliminary layer 14 are irradiated with pulsed light. In the case of n times of repeated irradiation, the cycle of Fig. 2 (on + off) is repeated n times. Further, in the case of the reverse irradiation, it is preferable to cool the support film 10 from the side of the support film 10 in order to cool the support film 10 to the vicinity of the room temperature when the next pulsed light is irradiated.

Further, as the pulse light, an electromagnetic wave having a wavelength range of 1 pm to 1 m, preferably an electromagnetic wave having a wavelength range of 10 nm to 1000 μm (far ultraviolet ray to far infrared ray), and further preferably an electromagnetic wave having a wavelength range of 100 nm to 2000 nm can be used. Examples of such electromagnetic waves include gamma rays, X-rays, ultraviolet rays, visible rays, infrared rays, and the like. In the case where the wavelength is too short, the damage of the support film 10 (resin substrate) and the adhesive layer 12 for pattern printing is large, and it is not preferable. Further, in the case where the wavelength is too long, it is not efficiently absorbed and is heated, which is not preferable. That is, the wavelength range is particularly preferably in the range of ultraviolet rays to infrared rays among the above wavelengths, more preferably in the range of 100 to 2000 nm.

The irradiation time (on) of the pulsed light is different depending on the light intensity, but is preferably in the range of 20 microseconds to 50 milliseconds. When it is shorter than 20 microseconds, the sintering of the metal nanowire and/or the metal nanotube can not be performed, and the effect of improving the performance of the conductive layer 16 is lowered. In addition, if it is longer than 50 milliseconds, the support film 10, the adhesive layer 12, and the like are adversely affected by photodegradation and thermal deterioration, and it is easy to blow the metal nanowire and/or the metal nanotube. More preferably 40 microseconds to 10 milliseconds. For the above reasons, in the present embodiment, pulsed light is used without using continuous light. Pulsed light irradiation even if Single irradiation is also effective, but it can be repeated as described above. In the case of repeated implementation, the irradiation interval (off) is preferably in the range of 20 microseconds to 5 seconds, more preferably in the range of 2 milliseconds to 2 seconds. When it is shorter than 20 microseconds, it becomes close to continuous light, and it is irradiated after the time of the one-time irradiation, and it is the possibility that the heating film temperature of the support film 10 and the adhesive layer 12 may become high and it may deteriorate. In addition, if it is longer than 5 seconds, the process time becomes longer and it is not good.

In the case of manufacturing the conductive pattern according to this embodiment, an Xenon-type pulse type illumination lamp or the like is used for the conductive preparation layer 14 as described above, and the irradiation pulse width (on) is 20 microseconds to 50 milliseconds, more preferably 40. The pulsed light of microseconds to 10 milliseconds is joined to the outer peripheral intersection of the metal nanowires and/or the metal nanotubes. Here, the bonding is because the material (metal) of the nanowire or the nanotube absorbs the pulsed light, causes internal heat generation, and the intersecting portion is fused and firmly connected, so that the surface resistance is lowered. By this bonding, the connection area between the nanowires of the intersection portion can be increased to lower the surface resistance. In this manner, by the irradiation of the pulsed light, the intersection of the metal nanowire and/or the metal nanotube is joined, and the metal nanowire and/or the metal nanotube is formed into a mesh-like conductive layer 16. Therefore, the conductivity of the conductive pattern can be improved. Further, the mesh formed by the metal nanowires and/or the metal nanotubes is not dense in a state where there is no vacancy interval. Since there is no space, the transmittance of light will decrease.

The conductive layer 16 obtained as described above has a surface resistivity of 5 to 1000 Ω/□ and a total light transmittance of 80% or more, and a surface resistivity of 10 to 200 Ω/□, and It is better to have a light transmittance of 90% or more.

Further, after the pulsed light is irradiated, a protective film may be attached to the upper portion of the conductive layer 16 as a protective layer 18 to protect the conductive layer 16. Thereby, it is possible to prevent the conductive layer 16 from being affected by oxidation or vulcanization, or adhesion or foreign matter adhesion. It is preferable that the protective film is chemically stable and thermally stable, and is easily peeled off from the conductive layer 16. Specifically, those having a thin sheet shape such as polyethylene, polypropylene, polyethylene terephthalate or polyvinyl alcohol and having a high surface smoothness are preferred. Also included is a mold release process for imparting peelability to the surface. When the thickness of the protective film is too thin, it is not easy to handle and the protective effect is not sufficiently exerted. If it is too thick, the cost becomes unfavorable, so 5 to 500 μm is preferable, and more preferably 10 to 188 μm. Further, pulsed light may be irradiated after attaching a protective film to the upper portion of the conductive layer.

[Examples]

Hereinafter, embodiments of the invention will be specifically described. Further, the following examples are examples for easily understanding the present invention, and the scope of the present invention is not limited to the examples.

<Production of silver nanowire>

Poly N-vinylpyrrolidone K-90 (manufactured by Nippon Shokubai Co., Ltd.) (0.049 g), AgNO ₃ (0.052 g), and FeCl ₃ (0.04 mg) were dissolved in ethylene glycol (12.5 ml). The reaction was heated at 150 ° C for 1 hour. The obtained precipitate was separated by centrifugation, and the precipitate was dried to obtain a desired silver nanowire. The SEM images of the obtained silver nanowires are shown in Fig. 3 (a) and (b). The SEM used was FE-SEM S-5200 manufactured by Hitachi High-Technologies Corporation.

3(a) and 3(b), the silver nanowires have a linear shape, and the linear lines have a diameter of about 70 nm, a length of about 10 to 20 μm, and a linear shape of about 95% or more. Also, the rest is granular.

The above-mentioned ethylene glycol, poly N-vinylpyrrolidone K-90, AgNO ₃ , FeCl ₃ system and Wako Pure Chemical Industries, Ltd. were manufactured.

In addition, the length and diameter of the silver nanowire were measured by SEM and TEM. Further, the TEM used was a TEM manufactured by JEOL Ltd.; JEOL, JEM-2100 transmission electron microscope.

Example 1. Production of a film for transfer

As a support film, a release PET film (SP-PET-100-01BU, a PET film with a release layer of 100 μm, and a peeling layer of 100 μm, which was manufactured by Panac Co., Ltd.) was used as a support film, and the surface was used as an adhesive layer. A polymer A layer was formed. The polymer A layer was coated on a polystyrene resin by dissolving S-LEC KS-3 (a polyacetal resin produced by Sekisui Chemical Co., Ltd.) in a solution of ethyl acetate (about 10% by mass) so as to be 10 μm thick. After the epoxy coating was applied to the release PET film, it was formed by drying at 80 ° C for 1 hour. Next, a conductive ink containing a silver nanowire is applied onto the polymer A layer and dried to form a conductive preliminary layer. The conductive ink was prepared by dissolving a solution in which poly(N-vinylpyrrolidone K-30 was 1% by mass) in isopropyl alcohol, and the content of the silver nanowire was 0.1% by mass. This conductive ink was applied onto the above-mentioned adhesive layer using a glass rod, and then dried at 80 ° C for 1 hour to form a conductive preliminary layer. Conductive preparation layer The conductive preparation layer was changed into a conductive layer by pulsed light irradiation using a pulse irradiation apparatus Pulse Forge 3300 manufactured by NovaCentrix Co., Ltd. Further, the irradiation conditions of the pulsed light were a driving voltage of the light source of 600 V, and the irradiation time was irradiated once at 60 μsec. The surface resistivity is 80 Ω/□. The surface resistance value was measured using a LORESTA-GP MCP-T610 4 probe method surface resistivity and volume resistivity measuring apparatus manufactured by Mitsubishi Chemical Corporation. Finally, a protective film (protective layer) is deposited as a protective film (protective layer) on the conductive coating layer opposite to the conductive layer, and the film is deposited by rolling the glass rod over the protective film. A film for silver nanowire transfer was obtained.

Embodiment 2. Conductive pattern forming method

The transfer film obtained in Example 1 of 5 cm square was cut out, and the adhesive layer exposed after the support film was peeled off was laminated so as to face the glass substrate, by which the glass rod was rolled from one end to the film. On the glass substrate, a conductive layer (overall pattern) is transferred through the adhesive layer. After the transfer, the protective film was peeled off and the surface resistivity value of the conductive layer was measured. It was confirmed that the surface resistivity maintained the surface resistivity of the conductive film of the transfer film before transfer.

Example 3.

As a support film, a release PET film (SP-PET-100-01BU, a PET film with a release layer of 100 μm, and a peeling layer of 100 μm, which was manufactured by Panac Co., Ltd.) was used as a support film, and the surface was used as an adhesive layer. A polymer A layer was formed. Polymer A layer will be S-LEC KS-3 A solution obtained by dissolving a polyacetal resin in ethyl acetate (about 10% by mass) was applied to a polyoxynitride-coated release PET film by a bar coater so as to be 10 μm thick, and then dried at 80 ° C for 1 hour. form. Next, a conductive ink containing a silver nanowire is applied onto the polymer A layer and dried to form a conductive preliminary layer. The conductive ink was prepared by dissolving the solution in an amount of 1% by mass of poly-N-vinylpyrrolidone K-30 in isopropyl alcohol, and the content of the silver nanowire was 0.1% by mass. This conductive ink was applied onto the above-mentioned adhesive layer using a glass rod, and then dried at 80 ° C for 1 hour to form a conductive preliminary layer.

This transfer film 22 was cut out to 13 cm × 6 cm. Thereafter, two stainless steel sheets 24 each having a thickness of 2 cm × 8 cm × 3 mm were stacked as shown in Fig. 4, and pulsed light irradiation was performed using a helium gas irradiation apparatus Pulse Forge 3300 manufactured by NovaCentrix. Further, the irradiation conditions of the pulsed light were a driving voltage of the light source of 600 V, and the irradiation time was irradiated once at 60 μsec. When the surface resistivity of the silver nanowire layer was measured in the same manner as in Example 2, it was confirmed that the surface was covered with the stainless steel plate 24, and the surface was not irradiated, and the surface resistivity was 80 Ω/□. Then, the protective film was adhered to the conductive layer in the same manner as in the first embodiment, and after the support film was peeled off, the transfer film 22 was attached to the glass substrate via the adhesive layer in the same manner as in the example 2, and the conductive pattern was placed. Transfer to the glass substrate. After the transfer, the protective film was peeled off and the surface resistivity of the conductive layer was measured. The insulating portion was maintained in an insulating state, and the surface resistivity was 80 Ω/□, and the conduction was maintained.

Claims (14)

A method for forming a conductive pattern, comprising: a step of preparing a transfer film having a support film, an adhesive layer formed on the support film, and a transfer film having a conductive layer having a specific pattern shape formed on the adhesive layer, And a step of peeling off the support film of the transfer film and then adhering the conductive layer to the substrate through the adhesive layer; the conductive layer comprises a metal nanowire and/or a metal nanotube and an insulating binder resin, The metal nanowire and the metal nanotube are 100 parts by mass in total, and the insulating binder resin is contained in an amount of from 100 parts by mass to 2,500 parts by mass. The method of forming a conductive pattern according to claim 1, wherein the step of preparing the film for transfer has a conductive ink containing a metal nanowire and/or a metal nanotube coated on a subsequent layer to a specific one. a step of forming a conductive preliminary layer by patterning, and a step of forming a conductive layer comprising a metal nanowire and/or a metal nanotube by irradiating the conductive preliminary layer with pulsed light. The method of forming a conductive pattern according to the first aspect of the invention, wherein the step of preparing the film for transfer has a conductive ink comprising a metal nanowire and/or a metal nanotube on a bonding layer. a step of forming a conductive preliminary layer, and a step of forming a conductive layer comprising a metal nanowire and/or a metal nanotube by irradiating the conductive preliminary layer with pulsed light, and a pattern processing step of processing the conductive layer into a specific pattern . Such as the conductive pattern shape of any one of the patent scopes 1 to 3 In the method of preparing the film for transfer, the step of forming a protective layer on the main surface opposite to the main surface of the conductive layer including the adhesive layer, and removing the protective layer of the protective layer after the subsequent step step. A method for forming a conductive pattern, comprising: preparing a metal nanowire and/or a metal nanotube having a specific pattern shape on a support film, and an insulating binder resin, and a metal nanowire and a metal 100 parts by mass of the nanotubes, and the conductive film containing 100 parts by mass to 2500 parts by mass of the insulating binder resin and the film for transfer of the adhesive layer formed on the conductive layer, the film for transfer The layer is then followed by a subsequent step on the substrate, and the step of removing the aforementioned support film. A method of forming an on-cell type touch panel, wherein the substrate is a transparent substrate of a liquid crystal in which a liquid crystal display element is sealed, and the bonding layer is a method of forming a conductive pattern according to any one of claims 1 to 5. And being adhered to the surface of the transparent substrate opposite to the side on which the liquid crystal side is sealed. A film for transfer characterized by sequentially laminating a support film, an adhesive layer, and a metal nanowire and/or a metal nanotube having a specific pattern and an insulating binder resin, and for the metal nano 100 parts by mass of the wire and the metal nanotubes in total, containing 100 parts by mass to 2500 parts by mass of the conductive layer of the insulating binder resin. The film for transfer of claim 7, wherein the metal nanowires and/or the metal nanotubes of the conductive layer are in contact with each other At least a portion of the fork portion is fused. The film for transfer according to claim 7 or 8, wherein the conductive layer has a protective layer on a main surface opposite to a main surface on which the adhesive layer is provided. An on-cell type touch panel, which is characterized in that the transfer film of any one of claims 7 to 9 is attached to the opposite side of the transparent substrate on which the liquid crystal display element is sealed and which is sealed on the liquid crystal side. The face. The method for forming a conductive pattern according to claim 1 or 5, wherein the conductive component of the conductive layer is a metal nanowire and/or a metal nanotube. The film for transfer according to claim 7, wherein the conductive component of the conductive layer is a metal nanowire and/or a metal nanotube. The method for forming a conductive pattern according to claim 1 or 5, wherein the insulating binder resin is poly N-vinyl rotane ketone, poly N-vinyl caprolactam, poly N-vinyl acetamide , poly N-vinylformamide, epoxy resin, urethane acrylate resin, urethane resin, cyclic olefin polymer (COP, Cyclic Olefin Polymer), or cyclic olefin copolymer (COC, Cyclic Olefin Copolymer) . The film for transfer according to item 7 of the patent application, wherein the insulating binder resin is poly N-vinylrrolidone or poly N- Vinyl caprolactam, poly N-vinylacetamide, poly N-vinylformamide, epoxy resin, urethane acrylate resin, urethane resin, cyclic olefin polymer (COP, Cyclic Olefin Polymer ), or a cyclic olefin copolymer (COC, Cyclic Olefin Copolymer).