WO2014098230A1

WO2014098230A1 - Film formation method, conductive film, and insulation film

Info

Publication number: WO2014098230A1
Application number: PCT/JP2013/084292
Authority: WO
Inventors: 浩志松木; 基実松島; 富明大竹
Original assignee: 株式会社クラレ
Priority date: 2012-12-21
Filing date: 2013-12-20
Publication date: 2014-06-26
Also published as: JPWO2014098230A1; TW201442950A

Abstract

The purpose of the present invention is to provide a film having a pattern with a high resolution. The present invention is provided with: a step in which a conductive carbon layer is provided to one surface side of a base material; a step in which a conductive carbon layer is provided to another surface side of the base material; a step in which an overcoat layer is provided upon the conductive carbon layer provided to the one surface side; a step in which an overcoat layer is provided upon the conductive carbon layer provided to the other surface side; a step in which a mask having a prescribed pattern is provided upon the overcoat layer provided to the one surface side; a step in which a mask having a prescribed pattern is provided upon the overcoat layer provided to the other surface side; and a step in which, under an atmosphere provided with oxygen, the conductive carbon layers are irradiated with ultraviolet radiation in accordance with openings in the masks.

Description

Film forming method, conductive film, and insulating film

The present invention relates to a transparent conductive film, for example.

A transparent conductive film substrate in which a transparent conductive film (for example, a transparent conductive film made of indium tin oxide (ITO) or the like) is provided on a transparent substrate is known. This type of substrate is used for a display panel, for example. For example, it is used for a liquid crystal display. Used for plasma displays. Used for organic EL displays. Or it is used for a touch panel. Or it is used for a solar cell. In addition, it is used in various fields.

The transparent conductive film is formed in a desired pattern. As this pattern forming method, a chemical etching means (a photolithography means using a photoresist or an etchant) is generally employed.

The chemical etching method is a photoresist film forming process (applying a photoresist paint on the ITO film formed on the entire surface of the substrate) → photoresist film patterning process (exposure development forms the photoresist film into a predetermined pattern) ) → ITO film etching process (etching the ITO film using a predetermined pattern of photoresist film as a mask) → Photoresist film removing process is required. Therefore, the chemical etching method is cumbersome. The chemical etching method has a problem of a decrease in etching accuracy due to swelling of the photoresist film in the solution. The chemical etching method has problems in the handling of the etching solution and the waste solution treatment.

A laser ablation method has been proposed as a method for solving the above problems. In this method, unnecessary portions are removed by directly irradiating a conductive film with a laser. This method does not require a photoresist and enables highly accurate patterning.

However, in the laser ablation method, applicable substrates are limited. The laser ablation method has a high process cost. In the laser ablation method, the processing speed is slow. Therefore, the laser ablation method is not a method suitable for a mass production process.

Chemical etching techniques that do not require a photolithography process include “use of iron (III) chloride or iron (III) chloride hexahydrate as an etching component in a composition for etching an oxide surface”, “iron chloride” (III) or iron (III) chloride hexahydrate, in display technology (TFT), in photovoltaics, semiconductor technology, high performance electronics, mineralogy or glass industry, in OLED lighting, in the manufacture of OLED displays, and Use as an etching component in a composition in paste form for the manufacture of photodiodes and for the construction of ITO glass for flat panel screen applications (plasma displays) "" Composition for etching oxide layers " A) salt as an etching component Iron (III) or iron (III) chloride hexahydrate, b) solvent, c) optionally homogeneously dissolved organic thickener, d) optionally at least one inorganic acid and / or organic The composition ", which is in paste form and printable, comprising an acid and optionally e) additives such as antifoaming agents, thixotropic agents, flow control agents, degassing agents, adhesion promoters ( JP-T-2008-547232).

“An etching medium for etching a transparent conductive layer of an oxide, comprising phosphoric acid or a salt thereof or a phosphoric acid adduct or a mixture of phosphoric acid and a phosphate and / or a phosphoric acid adduct “Etching medium containing at least one etchant” “A method for etching a transparent conductive layer of oxide, characterized in that the etching medium is applied to a substrate to be etched by a printing process” It has been proposed (Japanese Patent Publication No. 2009-503825).

However, the techniques disclosed in Japanese Patent Publication No. 2008-547232 and Japanese Patent Publication No. 2009-503825 do not allow etching to progress uniformly in the plane. For this reason, unevenness occurs.

Incidentally, as the transparent conductive film, a transparent conductive film made of carbon nanotubes is known in addition to the transparent conductive film made of ITO. The carbon nanotube is a tube-shaped material having a diameter of 1 μm or less. An ideal carbon nanotube has a structure in which a carbon hexagonal mesh surface is parallel to the tube axis to form a tube. The tubes may be multiplexed. Carbon nanotubes exhibit metallic or semiconducting properties depending on how the hexagonal network made of carbon is connected and the thickness of the tube. For this reason, carbon nanotubes are expected as functional materials. However, depending on the configuration and manufacturing method of the carbon nanotube, the thickness and direction are random. For this reason, in use, there are cases where it is necessary to recover after the synthesis and purify it, and to treat it according to the form to be used. The following methods have been proposed as a patterning method for this type of carbon nanotube (Japanese Patent Publication No. 2006-513557, Japanese Patent Publication No. 2007-529884 (Pamphlet of International Publication No. 2005/086982)). For example, a carbon nanotube dispersion is applied to the substrate surface. Thereby, a carbon nanotube film is formed. A binder solution is applied to the carbon nanotube film in a predetermined pattern. After application, the solvent is removed by drying. Thereby, the binder remains in the carbon nanotube film, and the network of carbon nanotubes is strengthened. Thereafter, the substrate is washed with a solvent that does not dissolve the binder. As a result, a pattern is formed in which only the portion where the binder exists (to which the binder has been applied) remains. A photoresist material can also be used instead of the binder. That is, a photoresist-containing paint is applied to the carbon nanotube film. Thereby, the photoresist is impregnated in the network of carbon nanotubes. Thereafter, a predetermined pattern is formed using photolithography. However, the method of patterning after forming the carbon nanotube film on the entire surface of the substrate is complicated.

There is also a method in which a pre-patterned carbon nanotube film is directly applied and formed on a substrate by an application method such as screen printing, inkjet, or gravure printing. When the patterned carbon nanotube film is formed by a coating method such as screen printing, it is necessary that the physical properties of the carbon nanotube-containing coating are adjusted to the physical properties suitable for the coating method. The carbon nanotube dispersion generally contains a dispersant such as a surfactant. Relatively low viscosity. In order to obtain ink physical properties suitable for the coating method, it is necessary to add a material for adjusting the viscosity and surface tension to the carbon nanotube dispersion. In this case, the dispersibility of the carbon nanotubes may be deteriorated.

The following technology has been proposed (international publication 2010/113744 pamphlet) as an alternative to the technology proposed in JP-T-2006-513557 and JP-T-2007-529884. That is, an acid having a boiling point of 80 ° C. or higher (for example, sulfuric acid or a sulfonic acid compound), a base having a boiling point of 80 ° C. or higher, or a compound, solvent, resin (for example, primary to fourth that generates an acid or a base by external energy) Cationic resins containing any of the primary amino groups as part of the structure) and conductive film removing agents containing leveling agents have been proposed. The conductive film removing agent is applied to at least a part of the base material with a conductive film having a conductive film containing a whisker-like conductor, a fibrous conductor (for example, carbon nanotube) or a particulate conductor on the base material. There has been proposed a conductive film removal method including a process, a process of heat treatment at 80 ° C. or higher, and a process of removing the conductive film by cleaning with a liquid. There has been proposed a conductive film removal method for removing the overcoat layer and the conductive film from a conductive film-containing substrate having an overcoat layer on the conductive film. When the conductive film remover is applied and then heated to 80 to 200 ° C., the conductive film in the portion where the conductive film remover is applied is decomposed, dissolved or solubilized, and has an overcoat layer. It is said that the overcoat layer and the conductive film are decomposed, dissolved or solubilized.

Special table 2008-547232 gazette Special table 2009-503825 gazette Special table 2006-513557 gazette JP-T 2007-529884 (International Publication No. 2005/086982 Pamphlet) International Publication 2010/113744 Pamphlet

The carbon nanotube is exposed on the side surface (vertical wall surface) of the pattern formed by the technique using the conductive film remover of Patent Document 5. This is because even if an overcoat layer is provided on the upper surface of the carbon nanotube layer, the carbon nanotube layer and the overcoat layer are removed by the conductive film removing agent. That is, there is a carbon nanotube surface that is not covered with the overcoat layer. For this reason, a decrease in durability (for example, dropping of carbon nanotubes, change in physical properties due to moisture, etc.) can be considered.

Furthermore, there may be a problem that the surface is uneven.

The technique of Patent Document 5 requires a heating step of heating the conductive film remover applied in a predetermined pattern to 80 ° C. or higher. Therefore, workability is poor. Furthermore, the substrate is required to have a heat resistance of 80 ° C. or higher. This reduces the degree of freedom in substrate selection.

The present invention aims to solve the above problems. In particular, the problem to be solved by the present invention is to provide a conductive (or insulating) film having high resolution and excellent durability by a simple method.

】 The above problems were studied with eagerness.

As a result, the following has been found. An overcoat layer was provided on a conductive film (for example, a conductive film formed by applying conductive carbon nanotubes). A mask for shielding (shielding) ultraviolet rays was provided on the overcoat layer. Ultraviolet rays were irradiated through the mask in a predetermined pattern. In particular, ultraviolet rays were irradiated in an atmosphere containing oxygen. The pattern thus formed had high pattern accuracy. The durability of the conductive film (insulating film) was excellent. Moreover, pattern formation was simple. Here, the conductive film having a predetermined pattern is an insulating film having a predetermined pattern when viewed from the opposite standpoint.

The present invention has been achieved based on the above findings.

The present invention
A method of forming a film with a predetermined pattern in which the conductive carbon layer in the ultraviolet irradiation region is modified to be insulative, and the conductive carbon layer in the non-ultraviolet irradiation region retains conductivity,
A step in which a conductive carbon layer is provided on one side of the substrate;
A step in which a conductive carbon layer is provided on the other side of the substrate;
A step of providing an overcoat layer on the conductive carbon layer provided on the one surface side;
A step of providing an overcoat layer on the conductive carbon layer provided on the other side;
A step of providing a mask having a predetermined pattern on the overcoat layer provided on the one surface side;
A step of providing a mask having a predetermined pattern on the overcoat layer provided on the other surface side;
And a step of irradiating the conductive carbon layer with ultraviolet rays corresponding to the opening of the mask in an atmosphere containing oxygen.
The present invention
A method of forming a film with a predetermined pattern in which the conductive carbon layer in the ultraviolet irradiation region is modified to be insulative, and the conductive carbon layer in the non-ultraviolet irradiation region retains conductivity,
A step in which a conductive carbon layer is provided on one side of the substrate;
A step in which a conductive carbon layer is provided on the other side of the substrate;
A step of providing an overcoat layer on the conductive carbon layer provided on the one surface side;
A step of providing an overcoat layer on the conductive carbon layer provided on the other side;
A step of providing a mask having a predetermined pattern on the overcoat layer provided on the one surface side;
A step of providing a mask having a predetermined pattern on the overcoat layer provided on the other surface side;
A step of irradiating the conductive carbon layer with ultraviolet rays corresponding to the opening of the mask in an atmosphere containing oxygen;
And a step of removing the mask after the ultraviolet irradiation.

The present invention is the film forming method, wherein the overcoat layer is preferably composed of a composition containing at least one selected from the group of hydrolyzable hydrolyzable organosilanes. A film forming method is proposed.
The present invention proposes the film forming method, wherein the overcoat layer preferably has a thickness of 1 nm to 1 μm.

The present invention proposes the film forming method, wherein the mask is preferably made of a resin that does not transmit ultraviolet rays, and is provided as a resin layer by a printing unit.
The present invention proposes the film forming method, wherein the mask is preferably provided in close contact with the overcoat layer.

The present invention proposes the film forming method, wherein the ultraviolet ray is an ultraviolet ray having a wavelength in the range of 10 to 400 nm.
The present invention proposes the film forming method, wherein the ultraviolet ray is preferably an ultraviolet ray having a wavelength in the range of 150 to 180 nm.
The present invention proposes the above film forming method, wherein the cumulative amount of irradiated ultraviolet light is preferably 50 to 500,000 mJ / cm ² .
The present invention proposes the above-described film forming method, wherein the ultraviolet light irradiation accumulated light amount is preferably 500 to 30000 mJ / cm ² .

The present invention proposes the film forming method, wherein the atmosphere containing oxygen preferably has an oxygen pressure of 101 to 21273 Pa.
The present invention proposes the film forming method, wherein the atmosphere containing oxygen preferably has an oxygen pressure of 1013 to 10130 Pa.

The present invention proposes the film forming method, wherein the conductive carbon layer is preferably composed of graphene.
The present invention proposes the film forming method, wherein the conductive carbon layer is preferably composed of carbon nanotubes.
The present invention proposes the above film forming method, wherein the conductive carbon layer is preferably composed of acid-treated single-walled carbon nanotubes.

The present invention proposes a conductive film formed by the film forming method.

The present invention proposes an insulating film formed by the film forming method.

A conductive (or insulating) film with high resolution can be easily obtained.

Schematic sectional view showing the layer structure before UV irradiation Schematic sectional view showing the layer structure after UV irradiation Plan view of resin layer (mask)

The first aspect of the present invention is a film forming method. The method is, for example, a method of forming a conductive film having a predetermined pattern. Alternatively, it is a method of forming an insulating film having a predetermined pattern. The method is a method of forming a transparent conductive film having a predetermined pattern. Alternatively, a transparent insulating film having a predetermined pattern is formed. The method is a film formation method of a predetermined pattern in which the conductive carbon layer in the ultraviolet irradiation region is modified to be insulative and the conductive carbon layer in the non-ultraviolet irradiation region retains conductivity. The above-described method is an insulating film forming method, particularly if the portion modified to be insulating is taken up. The above method is a method for forming a conductive film, particularly if the conductive part is taken up. The method includes the step of providing a conductive carbon layer. The conductive carbon layer is provided on both surfaces (front surface and back surface) of the substrate. There are cases where they are provided simultaneously on both sides, and cases where they are provided on the other side after being provided on one side. Either may be adopted. For example, a conductive carbon (for example, conductive graphene (conductive carbon nanotube))-containing (for example, dispersed) paint is applied onto a base material (for example, a substrate). By this coating, a conductive carbon layer is provided. A method other than coating may be used. For example, CVD (chemical vapor deposition method) and PVD (physical vapor deposition method) can be used. However, it is preferable to employ a coating method. The method includes a step of providing an overcoat layer on the conductive carbon layer. For example, an overcoat paint is applied on the conductive carbon layer. This coating forms an overcoat layer. An overcoat layer is provided on the conductive carbon layer provided on the front surface side (one surface side). An overcoat layer is provided on the conductive carbon layer provided on the back side (the other side). The overcoat layer may be provided simultaneously, or may be provided on the other side after being provided on the one side. Either may be adopted. The conductive carbon layer and the overcoat layer may be simultaneously provided by a simultaneous multilayer coating method. Alternatively, they may be provided separately. The method includes the step of providing a mask on the overcoat layer. Here, the mask is described in the case of a resin layer made of a material that does not transmit ultraviolet rays. However, the mask is not limited to this. The resin layer is provided on an overcoat layer provided on the front surface side (one surface side). The resin layer is provided on an overcoat layer provided on the back surface side (other surface side). The resin layer may be provided on both sides simultaneously, or may be provided on the other side after being provided on one side. Either may be adopted. The conductive overcoat layer and the resin layer may be provided simultaneously by a simultaneous multilayer coating method. Alternatively, they may be provided separately. The overcoat layer and the resin layer are preferably in close contact with each other. Adhesion means that a special force is required for peeling. That is, [bonding strength (peel strength) between the overcoat layer and the resin layer]> 0. It means that ultraviolet rays do not enter the boundary between the overcoat layer and the resin layer. It means that oxygen (active oxygen) does not enter the boundary between the overcoat layer and the resin layer. In this sense, a particularly large adhesive strength (peel strength) is not necessary. The resin layer has a predetermined pattern. The resin layer is provided at a location corresponding to a location (pattern) where the conductive carbon layer maintains conductivity. The resin layer is not provided at a location corresponding to a location (pattern) where the conductive carbon layer loses conductivity and becomes insulating. That is, the resin layer having the predetermined pattern functions as a mask for forming a conductive film (insulating film) having a predetermined pattern. Various resins can be used as the resin that does not transmit ultraviolet rays. For example, a resist material, a photocurable resin, a thermosetting resin, a thermoplastic resin, and the like can be given. Of course, it is not limited to this. The resin layer having the predetermined pattern is formed by printing means such as screen printing. Alternatively, it is formed using a photolithography technique. Of course, it is not limited to this. The method includes a step of irradiating with ultraviolet rays in an oxygen-containing atmosphere after the resin layer having the predetermined pattern is provided. In this irradiation step, the conductive carbon in the lower position where the resin layer exists is not irradiated with ultraviolet rays. The conductive carbon in the lower position where the resin layer does not exist is irradiated with ultraviolet rays. Ultraviolet rays are irradiated to the portions that should be insulated. The ultraviolet non-irradiated region is a region where electrical conductivity should be ensured. The ultraviolet irradiation region is a region where conductivity should be lost. In order to form a conductive film (or insulating film) having a predetermined pattern, ultraviolet irradiation is performed. Adhesion between the overcoat layer and the mask was improved by using the resin layer (resin mask). Thereby, it is difficult for the ultraviolet rays to reach a portion where the ultraviolet rays are masked or a portion where the activated oxygen due to the ultraviolet irradiation is masked. As a result, the pattern accuracy of the conductive film (insulating film) is increased. A film with a high resolution pattern was obtained. The overcoat layer is preferably composed of a composition containing at least one selected from the group of hydrolyzable organosilane hydrolysates. The ultraviolet rays are preferably ultraviolet rays having a wavelength in the range of 10 to 400 nm. More preferred is ultraviolet light having a wavelength in the range of 150 to 260 nm. Particularly preferred is ultraviolet light having a wavelength in the range of 150 to 180 nm. The atmosphere containing oxygen preferably has an oxygen pressure (oxygen partial pressure in the case of a mixed gas) of 101 to 21273 Pa. More preferably, the oxygen pressure is 507-20260 Pa. Particularly preferably, the oxygen pressure is 1013 to 10130 Pa. The conductive carbon layer is made of graphene, for example. The conductive carbon layer (graphene layer) is composed of, for example, carbon nanotubes. The conductive carbon layer (carbon nanotube layer) is composed of single-walled carbon nanotubes, for example. The conductive carbon layer (carbon nanotube layer) is composed of, for example, single-walled carbon nanotubes subjected to acid treatment. The carbon nanotube is preferably a carbon nanotube of G (intensity at a Raman peak common to graphite substances appearing near 1590 cm ⁻¹ ) / D (intensity at a Raman peak due to defects appearing near 1350 cm ⁻¹ ) ≧ 10 . The upper limit value of G / D is about 150, for example.

The second aspect of the present invention is a conductive film. The film is a conductive film formed by the film forming method.

The third aspect of the present invention is an insulating film. The film is an insulating film formed by the film forming method.

The following is a more detailed explanation.

1 to 3 are explanatory views of an embodiment of the present invention. FIG. 1 is a schematic cross-sectional view showing the layer structure before ultraviolet irradiation, FIG. 2 is a schematic cross-sectional view showing the layer structure after ultraviolet irradiation, and FIG. 3 is a plan view of a resin layer (mask) provided on the overcoat layer. is there.

1 is a transparent conductive carbon layer.
The transparent conductive carbon layer 1 is made of graphene, for example.
The transparent conductive carbon layer 1 was made of carbon nanotubes, for example.
The transparent conductive carbon layer 1 was composed of, for example, single-walled carbon nanotubes.
The transparent conductive carbon layer 1 is composed of, for example, single-walled carbon nanotubes that have been subjected to acid treatment.

Examples of the carbon nanotubes (CNT) constituting the transparent conductive carbon layer 1 include single-walled carbon nanotubes, double-walled carbon nanotubes, and multi-walled carbon nanotubes.
Single-walled carbon nanotubes are preferred. In particular, single-walled carbon nanotubes having a G / D of 10 or more (for example, 20 to 60) are preferable.
CNTs having a diameter of 0.3 to 100 nm are preferable. In particular, CNT having a diameter of 0.3 to 2 nm is preferable.
CNTs having a length of 0.1 to 100 μm are preferred. In particular, CNTs having a length of 0.1 to 5 μm are preferable.
The CNTs in the transparent conductive carbon layer 1 are intertwined with each other, for example.

The single-walled carbon nanotube may be a single-walled carbon nanotube obtained by any manufacturing method. For example, single-walled carbon nanotubes obtained by production methods such as arc discharge, chemical vapor deposition, and laser evaporation can be used.
From the viewpoint of crystallinity, single-walled carbon nanotubes obtained by an arc discharge method are preferred. This is easily available.
The single-walled carbon nanotube is preferably a single-walled carbon nanotube subjected to acid treatment. The acid treatment is performed by immersing single-walled carbon nanotubes in an acidic liquid. A technique called spraying may be employed instead of immersion. Various kinds of acidic liquids are used. For example, an inorganic acid or an organic acid is used. However, inorganic acids are preferred. For example, nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, or a mixture thereof can be used. Among these, acid treatment using nitric acid or a mixed acid of nitric acid and sulfuric acid is preferable. By this acid treatment, amorphous carbon was decomposed when single-walled carbon nanotubes and carbon fine particles were physically bonded through amorphous carbon. Both separated. The fine particles of the metal catalyst used in the production of the single-walled carbon nanotube were decomposed. A functional group is attached by the acid treatment. The conductivity was improved by the acid treatment.
The single-walled carbon nanotube is preferably a single-walled carbon nanotube in which impurities are removed by filtration and purity is improved. This is because a decrease in conductivity and a decrease in light transmittance due to impurities are prevented. Various methods are employed for filtration. For example, suction filtration, pressure filtration, cross flow filtration and the like are used. Among these, from the viewpoint of scale-up, it is preferable to employ cross flow filtration using a hollow fiber membrane.

The conductive layer (carbon nanotube layer) 1 preferably contains fullerene in addition to the CNT.
The conductive layer 1 preferably contains the above-mentioned CNT and fullerene.
In the present specification, “fullerene” includes “fullerene analog”.
This is because heat resistance is improved by including fullerene. It is because it was excellent also in electroconductivity.
The fullerene may be any fullerene. For example, C60, C70, C76, C78, C82, C84, C90, C96 etc. are mentioned. Of course, a mixture of plural kinds of fullerenes may be used.
From the viewpoint of dispersion performance, C60 is particularly preferable. Furthermore, C60 is easy to obtain. Not only C60 but also a mixture of C60 and another kind of fullerene (for example, C70) may be used.
The fullerene may contain metal atoms.
Examples of the fullerene analog include those having a functional group (for example, a functional group such as OH group, epoxy group, ester group, amide group, sulfonyl group, ether group). Examples also include phenyl-C61-propyl acid alkyl ester and phenyl-C61-butyric acid alkyl ester. Examples thereof include hydrogenated fullerene. Among them, fullerene having an OH group (hydroxyl group) (fullerene hydroxide) is preferable. This is because the dispersibility during coating of the single-walled carbon nanotube dispersion was high. When the number of OH groups is small, the degree of improvement in dispersibility of the single-walled carbon nanotube is lowered. On the other hand, if too much, synthesis is difficult. Accordingly, the number of OH groups is preferably 5 to 30 per molecule of fullerene. In particular, 8 to 15 are preferable. When there is too much addition amount (content) of fullerene, electroconductivity will fall. Conversely, if the amount is too small, the effect is poor. Therefore, the amount of fullerene is preferably 10 to 1000 parts by mass (particularly 20 parts by mass or more and 100 parts by mass or less) with respect to 100 parts by mass of CNT.

The transparent conductive carbon layer (carbon nanotube layer) 1 may contain a binder resin. However, from the viewpoint of conductivity, it is preferable not to include a binder resin. For example, when entangled CNTs are used, there is no need for a binder resin. The CNTs that are intertwined are in direct contact with each other. Since no insulator is interposed between them, the conductivity is good. If the surface of the conductive film is observed with a scanning electron microscope, it can be confirmed / determined whether the structure is intertwined with CNTs.

Reference numeral 2 denotes a base material (substrate). The transparent conductive carbon layer 1 is provided on both front and back (upper and lower) surfaces of a base material (substrate) 2.
The transparent conductive carbon layer 1 is configured by applying a CNT dispersion liquid (a dispersion liquid in which CNT having the above characteristics and fullerene added as necessary are dispersed) on a substrate (substrate) 2. The Examples of the coating method include die coating, knife coating, spray coating, spin coating, slit coating, micro gravure, flexo and the like. Of course, it is not limited to this. The carbon nanotube dispersion liquid is applied to the entire surface of the substrate 2. The transparent conductive carbon layer (carbon nanotube layer) 1 is preferably formed uniformly in order to uniformly promote insulation during ultraviolet irradiation.

Various materials are appropriately used as the constituent material of the substrate 2. For example, polystyrene (PS), polymethyl methacrylate (PMMA), styrene-methyl methacrylate copolymer (MS), polycarbonate (PC), cycloolefin polymer (COP), cycloolefin copolymer (COC), polyethylene terephthalate (PET), A resin such as polyethylene naphthalate (PEN) is used. In the present invention, since heating is not required for pattern formation, the degree of required heat resistance is low. Therefore, even when a resin is used as the constituent material of the substrate 2, the degree of freedom in resin selection is high. In addition to the resin, an inorganic glass material or a ceramic material can be used.

In the present invention, an overcoat layer (protective layer) 3 is provided on the transparent conductive carbon layer 1.
The transparent conductive carbon layer 1 is provided on both the front and back surfaces of the substrate 2. Therefore, the overcoat layer (protective layer) 3 is also provided on the front surface side and the back surface side of the substrate 2.
The overcoat layer 3 is composed of an organic polymer material, an inorganic polymer material, or an organic-inorganic hybrid resin.
Examples of organic polymer materials include thermoplastic resins, thermosetting resins, cellulose resins, and photocurable resins. It is appropriately selected from the viewpoints of visible light transmittance, substrate heat resistance, glass transition point, film curing degree, and the like. Examples of the thermoplastic resin include polymethyl methacrylate, polystyrene, polyethylene terephthalate, polycarbonate, polylactic acid, and ABS resin. Examples of the thermosetting resin include phenol resin, melamine resin, alkyd resin, polyimide, epoxy resin, fluorine resin, and urethane resin. Examples of the cellulose resin include acetyl cellulose and triacetyl cellulose. Examples of the photocurable resin include various oligomers, monomers, resins containing a photopolymerization initiator, and the like.
Examples of the inorganic material include silica sol, alumina sol, zirconia sol, titania sol and the like. Examples thereof include a polymer obtained by hydrolyzing and dehydrating and condensing water or an acid catalyst to the inorganic material.
Examples of the organic-inorganic hybrid resin include those in which a part of the inorganic material is modified (for example, substituted or added) with an organic functional group, and resins mainly composed of various coupling agents such as a silane coupling agent. Etc.
If the overcoat layer 3 is too thick, the contact resistance of the conductive film increases. On the contrary, if the overcoat layer 3 is too thin, it is difficult to obtain an effect as a protective film. Accordingly, the thickness of the overcoat layer 3 is preferably 1 nm to 1 μm. In particular, 10 nm or more is preferable. 200 nm or less is preferable. Furthermore, 150 nm or less is preferable.

The overcoat layer 3 provided on the transparent conductive carbon layer (carbon nanotube layer) 1 is particularly preferably composed of a composition containing, for example, a hydrolyzate of hydrolyzable organosilane.
Preferably, it consists of a composition containing a tetrafunctional hydrolyzable organosilane.
In particular, it comprises a composition containing a hydrolyzate of a tetrafunctional hydrolyzable organosilane and a hydrolyzable organosilane having an epoxy group and an alkoxy group.
Among them, the content of the hydrolyzable organosilane hydrolyzate having an epoxy group and an alkoxy group is preferably 1 to 10% by weight based on the total solid content of the resin.
When a hydrolyzable organosilane cohydrolyzate having an epoxy group and an alkoxy group is contained, the epoxy group of the cohydrolyzate is a hydroxyl group contained in the substrate when the composition is applied and cured. And oxygen sites such as carbonyl groups. For this reason, the adhesion between the overcoat layer (protective film) and the transparent conductive carbon layer (carbon nanotube layer) 1 is improved.
It consists of a composition containing silica-based metal oxide fine particles. In some cases, the composition further comprises a hydrolyzate of hydrolyzable organosilane having a fluorine-substituted alkyl group.
The hydrolyzate of the hydrolyzable organosilane is preferably a product obtained by reacting at a water ratio of 1.0 to 3.0 with respect to the alkoxy group contained in the hydrolyzable organosilane.
The hydrolyzate of the hydrolyzable organosilane is preferably a compound having a polystyrene equivalent weight average molecular weight of 1000 to 2000.

The tetrafunctional hydrolyzable organosilane is a compound represented by, for example, SiX ₄ . X is a hydrolyzable group. For example, an alkoxy group, an acetoxy group, an oxime group, an enoxy group, and the like. In particular, it is a tetrafunctional hydrolyzable organoalkoxysilane represented by Si (OR ¹ ) ₄ . R ¹ is preferably a monovalent hydrocarbon group. For example, it is a monovalent hydrocarbon group having 1 to 8 carbon atoms. For example, it is an alkyl group having 1 to 8 carbon atoms (methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group). Examples of the tetrafunctional hydrolyzable organosilane used in the present embodiment include tetramethoxysilane and tetraethoxysilane. The hydrolyzable organosilane having an epoxy group and an alkoxy group is, for example, a compound represented by R ² Si (OR ³ ) ₃ or R ² R ⁴ Si (OR ³ ) ₂ . R ² is a group selected from an epoxy group, a glycidoxy group, and substituted products thereof. R ³ is a monovalent hydrocarbon group as in R ¹ . For example, methyl group, ethyl group, propyl group, butyl group, pentyl group and the like. R ⁴ is a group selected from hydrogen, an alkyl group, a fluoroalkyl group, an aryl group, an alkenyl group, a methacryloxy group, an epoxy group, a glycidoxy group, an amino group, and substituents thereof.
Examples of the hydrolyzable organosilane having an epoxy group and an alkoxy group used in this embodiment include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and γ-glycidoxypropyltrisilane. Examples thereof include ethoxysilane and γ-glycidoxypropyldimethoxymethylsilane.
As silica-based metal oxide fine particles, hollow silica fine particles are preferably used. The hollow silica fine particles are those in which cavities are formed inside the outer shell of the silica-based metal oxide. The outer shell is preferably a porous one having pores. It may be one in which the pores are closed and the cavity is sealed. As long as it contributes to lowering the refractive index of the formed film, it is not necessarily limited to the hollow silica described above.

In the case of an overcoat layer having such a composition, the light reflectance was lowered and the light transmittance was increased. High physical protection against friction. Protection was high against environmental changes such as heat and humidity. When such an overcoat layer 3 was provided, it was confirmed that the transparent conductive carbon layer (carbon nanotube layer) 1 was modified from conductive to insulating by ultraviolet irradiation in a short time. In the present invention, such an overcoat layer is provided on the transparent conductive carbon layer (carbon nanotube layer) 1 prior to the ultraviolet irradiation step.

The overcoat layer 3 is provided by applying a paint containing the above composition. As the application method, the method described in the application of the CNT dispersion liquid is employed. The coating is performed on the conductive layer (carbon nanotube layer). Moreover, it is applied to the entire surface. It is preferable that the overcoat layer 3 is also formed uniformly in order to make the insulation at the time of ultraviolet irradiation progress uniformly.

A resin layer (mask) 4 having a predetermined pattern was provided on the overcoat layer 3. The overcoat layer (protective layer) 3 is provided on the front surface side and the back surface side of the base material (substrate) 2. Therefore, the resin layer 4 having a predetermined pattern is also provided on the front surface side and the back surface side of the base material (substrate) 2. The pattern of the resin layer 4 provided on the front surface side and the pattern of the resin layer 4 provided on the back surface side may be the same or different. The transparent conductive carbon layer (carbon nanotube layer) 1 below the position where the resin layer 4 exists (on the substrate 2 side) is not irradiated with ultraviolet rays. The transparent conductive carbon layer (carbon nanotube layer) 1 below the position where the resin layer 4 does not exist (substrate 2 side) is irradiated with ultraviolet rays. The resin layer 4 functions as a mask. The resin constituting the resin layer 4 is a resin that does not transmit ultraviolet light having a wavelength used for insulation. For example, a resist material (for example, novolak resin, melamine resin, etc.), a photocurable resin (for example, acryloyl group-modified resin, etc.), a thermosetting resin (for example, epoxy resin, etc.), a thermoplastic resin (for example, acrylic resin, etc. Aromatic resin). The resin layer 4 does not only have a function of shielding ultraviolet irradiation from above. The resin layer 4 has high adhesion to the overcoat layer 3 to prevent leakage of ultraviolet rays (around) to a portion where conductivity is desired to be maintained, or leakage of active oxygen such as ozone generated from oxygen (entrance). To prevent. Thereby, highly accurate patterning was obtained. The formation method of the resin layer 4 is not specifically limited. For example, printing means such as screen printing, offset printing, ink jet printing, and gravure printing can be used. If the printing means is employed, a resin can be provided on the overcoat layer 3 at a predetermined pattern corresponding portion.

The transparent conductive carbon layer (carbon nanotube layer) 1 was irradiated with ultraviolet rays. This ultraviolet ray preferably has a wavelength of 10 to 260 nm. More preferably, the wavelength is 150 to 260 nm. Particularly preferably, the wavelength is 150 to 180 nm. More preferred is ultraviolet light having a wavelength of 160 to 175 nm. For example, when ultraviolet rays having a long wavelength exceeding 260 nm are irradiated, the ultraviolet rays irradiated from one surface may pass through the substrate and insulate the conductive carbon layer on the opposite surface side. In order to denature conductive carbon nanotubes into insulating carbon nanotubes, it was more preferable that the irradiated ultraviolet rays have a wavelength of 180 nm or less. For example, when irradiated with ultraviolet light (wavelength: 185 nm, 254 nm) from a low-pressure mercury lamp, the carbon nanotubes were easily denatured from conductive to insulating at the irradiated site. However, when the substrate 2 is made of a resin, a phenomenon called discoloration may be observed in the substrate 2 in some cases. For this reason, it was particularly preferable that the irradiated ultraviolet light has a wavelength of 180 nm or less, and further 175 nm or less. For example, ultraviolet rays (wavelength: 172 nm) from a xenon excimer lamp were particularly preferable. The ultraviolet irradiation time having the above characteristics is, for example, about 10 seconds to 1 hour. Preferably it is 1 minute or more. Preferably it is 40 minutes or less. The cumulative amount of UV irradiation was, for example, about 50 to 500,000 mJ / cm ² . Preferably, it was 100 to 100,000 mJ / cm ² . More preferably, it was 500 to 30,000 mJ / cm ² . The preferable integrated light amount varies somewhat depending on the thickness of the carbon nanotube layer. It varied greatly depending on the presence or absence of the overcoat layer. With the overcoat layer, the carbon nanotubes were modified from conductive to insulating in a short time. It also varied depending on the type and thickness of the overcoat layer. When the overcoat layer was a composition containing a hydrolyzate of hydrolyzable organosilane, the irradiation time was significantly shortened. The thickness of the overcoat layer 3 was preferably 10 nm to 200 nm. More preferably, it was 50 nm to 150 nm. 1a is an ultraviolet irradiation location. The ultraviolet irradiation part 1a is denatured to be insulating. Reference numeral 1b denotes a portion not irradiated with ultraviolet rays. The portion 1b not irradiated with ultraviolet rays remains conductive.

It was preferable that oxygen (or active oxygen) was present in the atmosphere during the ultraviolet irradiation. Even when UV irradiation was performed, no modification of the transparent conductive carbon layer (carbon nanotube layer) 1 from conductivity to insulation was observed in an oxygen-free state. The atmosphere containing oxygen preferably had an oxygen pressure of 101 to 21273 Pa. More preferably, the oxygen pressure was 507-20260 Pa. Particularly preferably, the oxygen pressure was 1013 to 10130 Pa.

The transparent conductive carbon layer (carbon nanotube layer) 1 becomes a conductive (or insulating) film having a predetermined pattern by ultraviolet irradiation. The present invention and the conventional pattern forming method are greatly different. That is, the overcoat layer (coating layer) 3 remains as it is. The conductive layer (insulating layer) remains covered with the overcoat layer 3. Not exposed. As a result, the protective effect of the conductive layer (insulating layer) is high. That is, the durability is high. For example, the conductive layer (insulating layer) is hardly chipped (dropped off). It is difficult for moisture (humidity) to enter the conductive layer (insulating layer). In order to obtain a conductive film having a predetermined pattern, there is no need to remove (etch away) the transparent conductive carbon layer (carbon nanotube layer) 1. Because it is not necessary to use chemicals for removal, it is environmentally friendly. A conductive film (insulating film) was obtained by a very simple operation.

After a film having a predetermined pattern was formed by ultraviolet irradiation, the resin layer 4 was removed as necessary. The removal method is not particularly limited. For example, a method of peeling using an adhesive sheet or roll, a method of rubbing using a brush or the like, and a method of dissolving (or peeling) using a chemical solution that dissolves or swells are appropriately used.

Hereinafter, description will be given with specific examples. The present invention is not limited to the following examples.

[Example 1]
The single wall carbon nanotubes (commercially available) synthesized by arc discharge were subjected to acid treatment, water washing, centrifugation and filtration. A surfactant (sodium dodecylbenzenesulfonate: SDBS) 0.2 wt% aqueous solution was added to the purified carbon nanotubes. The carbon nanotube-containing aqueous solution was subjected to a dispersion treatment using an ultrasonic device. Centrifugation was then performed. Thus, a carbon nanotube dispersion liquid (CNT: 3200 ppm) was obtained.

The carbon nanotube dispersion was applied to both the front and back (upper and lower) surfaces of the substrate 2. The substrate 2 is a PET film (MKZ-T4A: manufactured by Higashiyama Film). The application method is die coating. The coating thickness is 0.05 μm (thickness after drying). After application, ion exchange water cleaning was performed. Thereby, the surfactant contained in the coating film (carbon nanotube layer) was removed. This was followed by drying (1.5 minutes; 120 ° C.). Thus, the carbon nanotube layer (transparent conductive carbon layer) 1 was provided on both the front and back (upper and lower) surfaces of the PET film 2.

The overcoat layer 3 was provided on the front and back (upper and lower) both sides of the PET film 2. One overcoat layer 3 is provided on one carbon nanotube layer (transparent conductive carbon layer) 1, and the other overcoat layer 3 is provided on another carbon nanotube layer (transparent conductive carbon layer) 1. It was. As the structure of each overcoat layer 3, 1.5 wt% Aerocera (hydrolyzable organosilane-containing composition: manufactured by Panasonic Corporation) was used. The application method is die coating. The coating thickness is 0.1 μm (thickness after drying).

The resin layer (mask) 4 was provided on the front and back (upper and lower) both sides of the PET film 2. One resin layer 4 was provided on one overcoat layer 3, and the other resin layer 4 was provided on the other overcoat layer 3. The mask (resin layer) 4 having a predetermined pattern was formed by screen printing. That is, a thermosetting resin (X-100 CL1: manufactured by Taiyo Ink Manufacturing Co., Ltd.) was printed at a predetermined location. The coating thickness was 50 μm. Then, the hardening process was performed for 30 minutes at 100 degreeC in oven. A portion where the resin layer 4 is not provided is an opening 5. Ultraviolet rays were applied to the carbon nanotube layer (transparent conductive carbon layer) 1 from the opening 5. The opening 5 has a square shape with a line width of 100 μm and a side length of 5 mm.

Thereafter, ultraviolet light (wavelength: 172 nm) from a xenon excimer lamp was irradiated on both surfaces from above the resin layer (mask) 4 having a predetermined pattern. The atmosphere during ultraviolet irradiation was 94% nitrogen and 6% oxygen. The pressure by the mixed gas is 1.013 × 10 ⁵ Pa. The integrated light quantity of irradiated ultraviolet rays was 10,560 mJ / cm ² . After the irradiation, the resin layer 4 was peeled off and removed using an adhesive sheet.

The continuity between the inside and outside of the □ -shaped pattern was examined by a tester. As a result, it was found that there was no conduction (insulation) between the two.

Furthermore, the pattern shape (□ shape) of the opening 5 of the mask 4 and the pattern shape (□ shape) of the carbon nanotube conductive layer were compared. The agreement between the two was extremely high. That is, the transparent conductive film was formed with high accuracy.

[Comparative Example 1]
In Example 1, it carried out similarly except having set it as nitrogen atmosphere (oxygen partial pressure 0Pa: no oxygen).

The ultraviolet irradiation site was not modified from conductive to insulating in Comparative Example 1.

[Comparative Example 2]
In Example 1, it carried out similarly except that the overcoat layer 3 was not provided.

The ultraviolet irradiation site was not modified from conductive to insulating even in Comparative Example 2.

1 Transparent conductive carbon layer (carbon nanotube layer)
1a UV irradiation location (insulation modified location)
1b UV-irradiated area (transparent conductive area)
2 Substrate (base material)
3 Overcoat layer (hydrolyzable organosilane-containing composition layer)
4 Resin layer (mask)
5 opening (ultraviolet ray transmission part)

Claims

A method of forming a film with a predetermined pattern in which the conductive carbon layer in the ultraviolet irradiation region is modified to be insulative, and the conductive carbon layer in the non-ultraviolet irradiation region retains conductivity,
A step in which a conductive carbon layer is provided on one side of the substrate;
A step in which a conductive carbon layer is provided on the other side of the substrate;
A step of providing an overcoat layer on the conductive carbon layer provided on the one surface side;
A step of providing an overcoat layer on the conductive carbon layer provided on the other side;
A step of providing a mask having a predetermined pattern on the overcoat layer provided on the one surface side;
A step of providing a mask having a predetermined pattern on the overcoat layer provided on the other surface side;
And a step of irradiating the conductive carbon layer with ultraviolet rays corresponding to the opening of the mask in an atmosphere containing oxygen.
2. The film forming method according to claim 1, wherein the overcoat layer is composed of a composition containing at least one selected from the group of hydrolyzable hydrolyzable organosilanes.
3. The film forming method according to claim 1, wherein the overcoat layer has a thickness of 1 nm to 1 μm.
4. The film forming method according to claim 1, wherein the mask is made of a resin that does not transmit ultraviolet rays and is provided as a resin layer by printing means.
5. The film forming method according to claim 1, wherein the mask is provided in close contact with the overcoat layer.
6. The film forming method according to claim 1, wherein the ultraviolet ray is an ultraviolet ray having a wavelength in a range of 10 to 400 nm.
6. The film forming method according to claim 1, wherein the ultraviolet ray is an ultraviolet ray having a wavelength in a range of 150 to 180 nm.
The film forming method according to any one of claims 1 to 7, wherein the cumulative amount of ultraviolet irradiation is 50 to 500,000 mJ / cm 2 .
The film forming method according to any one of claims 1 to 7, wherein the cumulative amount of UV irradiation is 500 to 30000 mJ / cm 2 .
10. The film forming method according to claim 1, further comprising a step of removing the mask after the ultraviolet irradiation.
11. The film forming method according to claim 1, wherein the atmosphere containing oxygen has an oxygen pressure of 101 to 21273 Pa.
11. The film forming method according to claim 1, wherein the atmosphere containing oxygen has an oxygen pressure of 1013 to 10130 Pa.
13. The film forming method according to claim 1, wherein the conductive carbon layer is made of graphene.
The film forming method according to any one of claims 1 to 13, wherein the conductive carbon layer comprises carbon nanotubes.
The film forming method according to any one of claims 1 to 14, wherein the conductive carbon layer is composed of acid-treated single-walled carbon nanotubes.
A conductive film formed by the film forming method according to any one of claims 1 to 15.
An insulating film formed by the film forming method according to any one of claims 1 to 15.