JP6176295B2 - Method for forming conductive pattern - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a method for forming a conductive pattern and a conductive pattern substrate, and more particularly to a method for forming a conductive pattern used as an electrode wiring of a flat panel display such as a liquid crystal display element, a touch panel (touch screen), a solar cell, and lighting. The present invention relates to a conductive pattern substrate.

  Large electronic devices such as personal computers and televisions, small electronic devices such as car navigation systems, mobile phones, and electronic dictionaries, and display devices such as OA and FA devices that use liquid crystal display elements, touch panels, etc. have become widespread. ing. In these liquid crystal display elements and touch panels, a transparent conductive film is used for part of wiring, pixel electrodes, or terminals that are required to be transparent. Transparent conductive films are also used in devices such as solar cells and lighting.

  Conventionally, indium tin oxide (Indium-Tin-Oxide: ITO), indium oxide, tin oxide, etc. are used for the transparent conductive film material because it shows high transmittance to visible light. As electrodes provided on a substrate for a liquid crystal display element or the like, a pattern obtained by patterning a transparent conductive film made of the above-described material is mainly used.

  As a patterning method for the transparent conductive film, after forming a transparent conductive film on a substrate such as a substrate, a resist pattern is formed by photolithography, and a conductive pattern is formed by removing a predetermined portion of the conductive film by wet etching. The method to do is common. In the case of an ITO film and an indium oxide film, a mixed liquid composed of two liquids of hydrochloric acid and ferric chloride is often used as an etching liquid.

  ITO films, tin oxide films, and the like are generally formed by sputtering, but the properties of the transparent conductive film are likely to change depending on the sputtering method, sputtering power, gas pressure, substrate temperature, atmospheric gas type, and the like. Differences in the film quality of the transparent conductive film due to variations in sputtering conditions cause variations in the etching rate when the transparent conductive film is wet-etched, which tends to reduce the product yield due to patterning defects. In addition, the above-described method for forming a conductive pattern includes a sputtering process, a resist formation process, and an etching process, and the process is long and a great burden is imposed on the cost.

  Recently, in order to solve the above problems, attempts have been made to form a transparent conductive pattern using a material in place of ITO, indium oxide, tin oxide and the like. For example, in Patent Document 1 below, after a conductive layer containing conductive fibers such as silver fibers is formed on a substrate, a photosensitive resin layer is formed on the conductive layer, and then exposed through a pattern mask. A method of forming a conductive pattern to be developed is disclosed.

  In Patent Document 2, a conductive film for transfer including at least a peelable conductive layer on a support and an adhesive layer on the conductive layer is used, and the conductive layer is attached to the substrate via the adhesive layer. A method is disclosed, and it is disclosed that the conductive layer after transfer may be patterned.

  In Patent Document 3, a photosensitive conductive film including a conductive layer provided on a support film and a photosensitive resin layer provided on the conductive layer is used so that the photosensitive resin layer is in close contact with the substrate. A method of forming a conductive pattern that can form a conductive pattern by using a laminating method is disclosed.

US Patent Application Publication No. 2007/0074316 JP 2007-257963 A International Publication No. 2010/021224

  However, the methods described in Patent Documents 1 and 2 have a problem that the process of forming a conductive pattern becomes complicated.

  On the other hand, the method described in Patent Document 3 is a method by which a conductive pattern can be formed more easily. However, since a photosensitive resin layer is interposed between the substrate and the conductive layer, a connection provided on the surface of the substrate. A terminal etc. and a conductive pattern cannot be connected easily. The above problem also occurs in the method described in Patent Document 2.

  An object of the present invention is to provide a conductive pattern forming method and a conductive pattern substrate capable of easily forming a conductive pattern having a sufficiently small surface resistivity on a substrate with sufficient resolution.

  In order to solve the above problems, the present invention provides a photosensitive conductive film comprising a support film, a conductive layer containing conductive fibers, and a photosensitive resin layer containing a photosensitive resin in this order, and a base material A lamination step of laminating the conductive layer and the photosensitive resin layer so that the conductive layer is in close contact therewith, and a patterning step of forming a conductive pattern by exposing and developing the photosensitive resin layer on the substrate. A method for forming a conductive pattern is provided.

  According to the method for forming a conductive pattern of the present invention, a conductive pattern having a sufficiently small surface resistivity can be easily formed on a substrate with sufficient resolution. In addition, it is possible to easily connect a connection terminal or the like provided on the substrate surface and the conductive pattern.

  Although the detailed reason why the present invention has the above-mentioned effects is not necessarily clear, by laminating the conductive layer containing the conductive fiber and the photosensitive resin layer, when laminating from the conductive layer side on the base material, By properly impregnating the conductive resin layer with the photosensitive resin layer, adhesiveness is obtained on the surface of the conductive layer opposite to the photosensitive resin layer, and patterning can be performed with sufficient resolution in subsequent exposure and development. The present inventors speculate that the above is the case.

  The photosensitive resin layer preferably contains a binder polymer, a photopolymerizable compound having an ethylenically unsaturated bond, and a photopolymerization initiator. When the photosensitive resin layer contains such a component, it is possible to further improve the sticking property, the adhesion between the base material and the conductive pattern, and the patterning property of the conductive pattern.

  The binder polymer preferably has a carboxyl group. By containing a binder polymer having a carboxyl group, the developability of the photosensitive resin layer can be improved.

  In the method for forming a conductive pattern of the present invention, the laminate of the conductive layer and the photosensitive resin layer can have a minimum light transmittance of 80% or more in a wavelength region of 450 to 650 nm. When the conductive layer and the photosensitive resin layer satisfy such conditions, it is easy to increase the brightness in a display panel or the like.

  The conductive fiber may be a silver fiber. By being a silver fiber, adjustment of the electroconductivity of the conductive pattern formed becomes easier.

  The present invention also provides a conductive pattern substrate comprising a substrate and a conductive pattern formed on the substrate by the conductive pattern forming method of the present invention.

  Since the conductive pattern is formed by the method for forming a conductive pattern of the present invention, the conductive pattern substrate can include a conductive pattern having a sufficiently small surface resistivity and a sufficient resolution. Further, the formed conductive pattern can be electrically connected to a connection terminal or the like provided on the substrate surface.

  In the conductive pattern substrate, the surface resistivity of the conductive pattern is preferably 2000 Ω / □ or less. By setting the surface resistivity of the conductive pattern in such a range, it can function more effectively as a wiring or an electrode.

  ADVANTAGE OF THE INVENTION According to this invention, the formation method of a conductive pattern and a conductive pattern board | substrate which can form easily the conductive pattern with sufficiently small surface resistivity with sufficient resolution on a base material can be provided. Moreover, according to this invention, it becomes possible to connect easily the connection terminal etc. which are provided in the base-material surface, and a conductive pattern. Furthermore, according to the method for forming a conductive pattern of the present invention, the adhesion between the base material and the conductive layer can be sufficient, and the adhesion of the resulting conductive pattern to the substrate must be sufficient. Can do.

  Further, according to the present invention, since a conductive pattern can be directly formed on an object, a three-dimensional conductive wiring can be easily formed. For example, after forming an insulating film with an insulating resin or the like on a predetermined portion of a conductive pattern on a base material provided with an already prepared conductive pattern, the photosensitive conductive film is laminated, and the conductive pattern is formed. A conductive pattern crossing portion (bridge portion) can be provided in the insulating film portion while conducting conduction between the already formed conductive pattern not covered with the film and the newly formed conductive pattern. In this case, an oxide conductor such as ITO, a metal such as Cu, or the like can be used for the already produced conductive pattern, and conduction with these conductive patterns can be easily achieved.

It is a schematic cross section showing an example of a photosensitive conductive film. It is a schematic cross section which shows an example of the manufacturing method of a photosensitive conductive film. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic cross section for demonstrating one Embodiment of the formation method of the conductive pattern of this invention, (a) is a schematic cross section which shows a lamination process, (b) is the lamination | stacking formed by transferring a photosensitive film 2 is a schematic cross-sectional view showing a body, (c) is a schematic cross-sectional view showing an exposure step, and (d) is a schematic cross-sectional view showing a developing step. It is a top view which shows an example of the electrostatic capacitance type touch panel in which a transparent electrode exists in the same plane. It is a partially cutaway perspective view showing an example of a capacitive touch panel in which transparent electrodes are present on the same plane. FIG. 6 is a partial cross-sectional view taken along line VI-VI in FIG. 5. It is a figure for demonstrating an example of the manufacturing method of the capacitive touch panel in which a transparent electrode exists in the same plane, (a) is a partially notched perspective view which shows the board | substrate provided with a transparent electrode, (b) FIG. 3 is a partially cutaway perspective view showing the obtained capacitive touch panel. It is a figure for demonstrating an example of the manufacturing method of the electrostatic capacitance type touch panel in which a transparent electrode exists in the same plane, (a) is a fragmentary sectional view along the VIIIa-VIIIa line | wire in FIG. ) Is a partial cross-sectional view showing a step of providing an insulating film, and (c) is a partial cross-sectional view taken along line VIIIc-VIIIc in FIG. 7.

  Hereinafter, preferred embodiments of the present invention will be described in detail. In addition, “(meth) acrylate” in the present specification means “acrylate” and “methacrylate”. Similarly, “(meth) acryl” means “acryl” and “methacryl”, and “(meth) acryloyl” means “acryloyl” and “methacryloyl”.

  The method for forming a conductive pattern according to this embodiment prepares a photosensitive conductive film including a support film, a conductive layer containing conductive fibers, and a photosensitive resin layer containing a photosensitive resin in this order, A laminating step of laminating the conductive layer and the photosensitive resin layer so that the conductive layer is in close contact with the substrate, a patterning step of forming a conductive pattern by exposing and developing the photosensitive resin layer on the substrate, Is provided.

  In this specification, the boundary between the conductive layer and the photosensitive resin layer is not necessarily clear. The conductive layer only needs to have conductivity in the surface direction of the photosensitive layer, and the conductive layer may be mixed with the photosensitive resin layer. For example, the conductive layer may be impregnated with a composition constituting the photosensitive resin layer, or the composition constituting the photosensitive resin layer may be present on the surface of the conductive layer.

  FIG. 1 is a schematic cross-sectional view showing an example of a photosensitive conductive film. A photosensitive conductive film 10 shown in FIG. 1 includes a first film (support film) 1, a photosensitive layer 4 provided on the first film 1, and a second film provided on the photosensitive layer 4 ( Cover film) 5. The photosensitive layer 4 includes a conductive layer 2 containing conductive fibers provided on the support film 1 and a photosensitive resin layer 3 provided on the conductive layer 2.

  Hereinafter, each of the support film 1 constituting the photosensitive conductive film 10, the conductive layer 2 containing conductive fibers, the photosensitive resin layer 3, and the cover film 5 will be described in detail.

  Examples of the support film 1 include polymer films having heat resistance and solvent resistance such as polyethylene terephthalate film, polyethylene film, polypropylene film, and polycarbonate film. Among these, a polyethylene terephthalate film and a polypropylene film are preferable from the viewpoints of transparency and heat resistance.

  The polymer film is preferably subjected to a release treatment so that it can be easily peeled off from the conductive layer 2 later.

  In this embodiment, the support film 1 can be separated from the cover film 5 preferentially. For this purpose, the adhesive strength between the cover film 5 and the photosensitive resin layer 3 is preferably larger than the adhesive strength between the conductive layer 2 and the support film 1. These polymer films are preferably subjected to thickness adjustment, material selection, and surface treatment so that they are more easily peeled off than the cover film 5. When adjusting the thickness, the ratio of the thickness of the support film 1 to the thickness of the cover film 5 is preferably 1: 1 to 1:10, and preferably 1: 1.5 to 1: 5. Preferably. More preferably, it is 1: 2 to 1: 5.

  The thickness of the support film 1 is preferably 5 to 100 μm, more preferably 10 to 50 μm, and particularly preferably 15 to 25 μm. By setting the thickness of the support film 1 to 5 μm or more, more sufficient mechanical strength can be obtained. For example, in the process of applying the conductive fiber dispersion for forming the conductive layer 2 or the photosensitive resin composition for forming the photosensitive resin layer 3, the support film is hardly broken and the handling property is improved. Excellent. By setting the thickness of the support film 1 to 100 μm or less, the peel strength between the support film 1 and the conductive layer 2 can be made appropriate and easy to peel off.

  Examples of the conductive fibers contained in the conductive layer 2 include metal fibers such as gold, silver, and platinum, and carbon fibers such as carbon nanotubes. These can be used alone or in combination of two or more. From the viewpoint of conductivity, it is preferable to use gold fiber and / or silver fiber, and from the viewpoint of easily adjusting the conductivity of the formed conductive pattern, it is more preferable to use silver fiber. Gold fiber and silver fiber can be used individually by 1 type or in combination of 2 or more types.

The metal fiber can be prepared by, for example, a method of reducing metal ions with a reducing agent such as NaBH ₄ or a polyol method. Commercially available products such as Unipym's Hipco single-walled carbon nanotubes can be used as the carbon nanotubes.

  The fiber diameter of the conductive fiber is preferably 1 to 50 nm, more preferably 2 to 20 nm, and particularly preferably 3 to 10 nm. The fiber length of the conductive fiber is preferably 1 to 100 μm, more preferably 2 to 50 μm, and particularly preferably 3 to 10 μm. The fiber diameter and fiber length can be measured with a scanning electron microscope.

  The thickness of the conductive layer 2 varies depending on the conductive pattern formed using the photosensitive conductive film of the present invention or its use, required conductivity, etc., but is preferably 1 μm or less, preferably 1 nm to 0.5 μm. It is more preferable that the thickness is 5 nm to 0.1 μm. When the thickness of the conductive layer 2 is 1 μm or less, the light transmittance in the wavelength region of 450 to 650 nm is high, the pattern formability is excellent, and it is particularly suitable for the production of a transparent electrode. The thickness of the conductive layer 2 refers to a value measured by a scanning electron micrograph.

  The conductive layer 2 preferably has a network structure in which conductive fibers are in contact with each other. The conductive layer 2 having such a network structure may be formed on the surface of the photosensitive resin layer 3 on the support film side, but conductivity is obtained in the surface direction on the surface exposed when the support film is peeled off. If it is, it may be formed in the form included in the support film side surface layer of the photosensitive resin layer 3.

  The conductive layer 2 containing conductive fibers is, for example, a conductive fiber dispersion obtained by adding the above-described conductive fibers to water and / or an organic solvent and, if necessary, a dispersion stabilizer such as a surfactant. After coating on the support film 1, it can be formed by drying. Further, after drying, the formed conductive layer 2 may be further pressurized. By forming the conductive layer under pressure, the number of contacts between the conductive fibers increases, and the conductivity can be improved. The linear pressure at this time is preferably 0.6 to 2.0 MPa, and more preferably 1.0 to 1.5 MPa. In the conductive layer 2, the conductive fiber may coexist with a surfactant, a dispersion stabilizer and the like.

  The coating can be performed by a known method such as a roll coating method, a comma coating method, a gravure coating method, an air knife coating method, a die coating method, a bar coating method, or a spray coating method. The drying can be performed at 30 to 150 ° C. for about 1 to 30 minutes using a hot air convection dryer or the like.

  The photosensitive resin layer 3 is formed from a photosensitive resin composition containing (A) a binder polymer, (B) a photopolymerizable compound having an ethylenically unsaturated bond, and (C) a photopolymerization initiator. Can be mentioned.

  Examples of the (A) binder polymer include acrylic resins, styrene resins, epoxy resins, amide resins, amide epoxy resins, alkyd resins, and phenol resins. These can be used alone or in combination of two or more. (A) The binder polymer can be produced by radical polymerization of a polymerizable monomer.

  Examples of the polymerizable monomer include polymerizable styrene derivatives substituted at the α-position or aromatic ring such as styrene, vinyl toluene, α-methylstyrene; acrylamide such as diacetone acrylamide; acrylonitrile; vinyl-n. -Ethers of vinyl alcohol such as butyl ether; (meth) acrylic acid alkyl ester, (meth) acrylic acid aryl ester, (meth) acrylic acid tetrahydrofurfuryl ester, (meth) acrylic acid dimethylaminoethyl ester, (meth) acrylic Acid diethylaminoethyl ester, (meth) acrylic acid glycidyl ester, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, (meth) acrylic acid, α -Bromoacryl , Maleic monoesters such as α-chloroacrylic acid, β-furylacrylic acid, β-styrylacrylic acid, maleic acid, maleic anhydride, monomethyl maleate, monoethyl maleate, monoisopropyl maleate, cyclohexyl maleate, Examples include fumaric acid, cinnamic acid, α-cyanocinnamic acid, itaconic acid, crotonic acid, and propiolic acid.

  Examples of the (meth) acrylic acid alkyl ester include (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid propyl ester, (meth) acrylic acid butyl ester, (meth) acrylic acid pentyl ester. , (Meth) acrylic acid hexyl ester, (meth) acrylic acid heptyl ester, (meth) acrylic acid octyl ester, (meth) acrylic acid 2-ethylhexyl ester, (meth) acrylic acid nonyl ester, (meth) acrylic acid decyl ester , (Meth) acrylic acid undecyl ester, (meth) acrylic acid dodecyl ester, (meth) acrylic acid dicyclopentanyl and the like.

  Examples of the (meth) acrylic acid aryl ester include benzyl (meth) acrylate.

  Other examples of the polymerizable monomer include bifunctional (meth) acrylic acid esters. Specifically, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (Meth) acrylate is mentioned. These can be used alone or in combination of two or more.

  In the present embodiment, the (A) binder polymer is preferably a copolymer containing structural units derived from (a) (meth) acrylic acid and (b) (meth) acrylic acid alkyl ester.

  (A) It is preferable that a binder polymer has a carboxyl group from a viewpoint of making alkali developability more favorable. Examples of the polymerizable monomer having a carboxyl group for obtaining such a binder polymer include (meth) acrylic acid as described above.

  (A) The ratio of the carboxyl group that the binder polymer has is 10 to 50% by mass as the ratio of the polymerizable monomer having a carboxyl group to the total polymerizable monomer used to obtain the binder polymer. Preferably, it is 12-40 mass%, More preferably, it is 15-30 mass%, It is especially preferable that it is 15-25 mass%. In terms of excellent alkali developability, the content is preferably 10% by mass or more, and in terms of excellent alkali resistance, it is preferably 50% by mass or less.

  (A) The weight average molecular weight of the binder polymer is preferably 10,000 to 200,000, but is preferably 15,000 to 150,000, more preferably 30000 to 150,000, and more preferably 30000 to 100,000 from the viewpoint of resolution. More preferably. In addition, the measurement conditions of a weight average molecular weight shall be the same measurement conditions as the Example of this-application specification.

  As the photopolymerizable compound as component (B), a photopolymerizable compound having an ethylenically unsaturated bond can be used.

  Examples of the photopolymerizable compound having an ethylenically unsaturated bond include a monofunctional vinyl monomer, a bifunctional vinyl monomer, and a polyfunctional vinyl monomer having at least three polymerizable ethylenically unsaturated bonds.

  Examples of the monofunctional vinyl monomer include (meth) acrylic acid, (meth) acrylic acid alkyl ester, and those co-polymerized as monomers used for the synthesis of a copolymer which is a preferred example of the component (A). Examples thereof include polymerizable monomers.

  Examples of the bifunctional vinyl monomer include polyethylene glycol di (meth) acrylate (having 2 to 14 ethoxy groups), trimethylolpropane di (meth) acrylate, and polypropylene glycol di (meth) acrylate (having the number of propylene groups). 2-14); bisphenol A polyoxyethylene di (meth) acrylate (2,2-bis (4- (meth) acryloxypolyethoxyphenyl) propane), bisphenol A diglycidyl ether di (meth) acrylate; And esterified products of a polyvalent carboxylic acid (such as phthalic anhydride) and a substance having a hydroxyl group and an ethylenically unsaturated bond (such as β-hydroxyethyl acrylate and β-hydroxyethyl methacrylate). Examples of the bisphenol A polyoxyethylene dimethacrylate include bisphenol A dioxyethylene diacrylate, bisphenol A dioxyethylene dimethacrylate, bisphenol A trioxyethylene diacrylate, bisphenol A trioxyethylene dimethacrylate, and bisphenol A pentaoxyethylene dimethacrylate. Examples thereof include acrylate, bisphenol A pentaoxyethylene dimethacrylate, bisphenol A deoxyoxyethylene diacrylate, and bisphenol A deoxyoxyethylene dimethacrylate.

  Examples of the polyfunctional vinyl monomer having at least three polymerizable ethylenically unsaturated bonds include trimethylolpropane tri (meth) acrylate, tetramethylolmethanetri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, dipenta Compounds obtained by reacting α, β-unsaturated carboxylic acids with polyhydric alcohols such as erythritol penta (meth) acrylate and dipentaerythritol hexa (meth) acrylate; containing glycidyl groups such as trimethylolpropane triglycidyl ether triacrylate And compounds obtained by adding an α, β-unsaturated carboxylic acid to the compound.

  (C) As a photopolymerization initiator, benzophenone, N, N, N ′, N′-tetramethyl-4,4′-diaminobenzophenone (Michler ketone), N, N, N ′, N′-tetraethyl-4, 4′-diaminobenzophenone, 4-methoxy-4′-dimethylaminobenzophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2-methyl-1- [4- ( Aromatic ketones such as methylthio) phenyl] -2-morpholino-propanone-1; 2-ethylanthraquinone, phenanthrenequinone, 2-tert-butylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, 2,3-benzanthraquinone 2-phenylanthraquinone, 2,3-diphenylanthraquinone, 1- Quinones such as loloanthraquinone, 2-methylanthraquinone, 1,4-naphthoquinone, 9,10-phenanthraquinone, 2-methyl-1,4-naphthoquinone, 2,3-dimethylanthraquinone; benzoin methyl ether, benzoin ethyl ether Benzoin ether compounds such as benzoin phenyl ether; benzoin compounds such as benzoin, methyl benzoin and ethyl benzoin; 1,2-octanedione, 1- [4- (phenylthio) phenyl-, 2- (O-benzoyloxime)], Oxime ester compounds such as ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (O-acetyloxime); 2,4,6-trimethylbenzoyl -Diphenyl-phosphine oxide, etc. Sphine oxide compounds; benzyl derivatives such as benzyldimethyl ketal; 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl) -4,5-di (methoxyphenyl) imidazole dimer , 2- (o-fluorophenyl) -4,5-diphenylimidazole dimer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methoxyphenyl) -4 2,4,5-triarylimidazole dimers such as 1,5-diphenylimidazole dimer; acridine derivatives such as 9-phenylacridine, 1,7-bis (9,9′-acridinyl) heptane; N-phenyl Examples thereof include glycine, N-phenylglycine derivatives, coumarin compounds, and oxazole compounds. Further, the substituents of the aryl groups of two 2,4,5-triarylimidazoles may give the same and symmetric compounds, or differently give asymmetric compounds. Moreover, you may combine a thioxanthone type compound and a tertiary amine compound like the combination of diethyl thioxanthone and dimethylaminobenzoic acid.

  Among these, an oxime ester compound or a phosphine oxide compound is preferable from the transparency of the photosensitive resin layer to be formed and the pattern forming ability when a thin film is formed.

  The blending amount of the (A) binder polymer is preferably 40 to 80 parts by mass with respect to 100 parts by mass as a total of (A) the binder polymer and (B) the photopolymerizable compound having an ethylenically unsaturated bond. 50 to 70 parts by mass is more preferable. By making the blending amount 40 parts by mass or more, the coating property (coating property) is excellent, and the phenomenon that the resin oozes out from the end of the photosensitive conductive film (photosensitive element) (also called edge fusion) is more Can be suppressed. Moreover, by making this compounding quantity 80 mass parts or less, a sensitivity can be improved and sufficient mechanical strength can be obtained.

  The blending amount of the (B) photopolymerizable compound having an ethylenically unsaturated bond is 20 with respect to 100 parts by mass of the total amount of (A) the binder polymer and (B) the photopolymerizable compound having an ethylenically unsaturated bond. It is preferable that it is -60 mass parts, and it is more preferable that it is 30-50 mass parts. By setting the blending amount to 20 parts by mass or more, sensitivity can be improved and sufficient mechanical strength can be obtained. Moreover, by making this compounding quantity into 60 mass parts or less, it is excellent in coating-film property (coating property), and edge fusion can be suppressed more.

  The blending amount of the (C) photopolymerization initiator is 0.1 to 20 parts by mass with respect to 100 parts by mass of the total amount of (A) the binder polymer and (B) the photopolymerizable compound having an ethylenically unsaturated bond. It is preferable that it is 0.2 to 10 parts by mass. When the blending amount is 0.1 parts by mass or more, the sensitivity can be improved. When the blending amount is 20 parts by mass or less, the photosensitive resin layer can be more uniformly cured by exposure.

  In the photosensitive resin composition of the present invention, if necessary, a dye such as malachite green, a photochromic agent such as tribromomethylphenylsulfone or leucocrystal violet, a thermochromic inhibitor, or a plastic such as p-toluenesulfonamide. Agents, pigments, fillers, antifoaming agents, flame retardants, stabilizers, adhesion-imparting agents, leveling agents, peeling accelerators, antioxidants, fragrances, imaging agents, thermal crosslinking agents and the like can be added. These additives may be added in an amount of about 0.01 to 20 parts by mass with respect to 100 parts by mass as a total of (A) the binder polymer and (B) the photopolymerizable compound. These are used alone or in combination of two or more.

  The photosensitive resin layer 3 is formed on the conductive layer 2 formed on the support film 1, as required, with methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N, N-dimethylformamide, propylene. It can be formed by coating a solution of a photosensitive resin composition having a solid content of about 10 to 60% by mass dissolved in a solvent such as glycol monomethyl ether or a mixed solvent thereof, and then drying. However, in this case, the amount of the remaining organic solvent in the photosensitive resin layer after drying is preferably 2% by mass or less in order to prevent the organic solvent from diffusing in the subsequent step.

  The coating can be performed by a known method such as a roll coating method, a comma coating method, a gravure coating method, an air knife coating method, a die coating method, a bar coating method, or a spray coating method. After coating, drying for removing the organic solvent and the like can be performed at 70 to 150 ° C. for about 5 to 30 minutes with a hot air convection dryer or the like.

  The thickness of the photosensitive resin layer 3 varies depending on the use, but is preferably 0.05 to 50 μm, more preferably 0.05 to 15 μm, and more preferably 0.1 to 10 μm after drying. More preferably, it is 0.1 to 8 μm, particularly preferably 0.1 to 5 μm. By making this thickness 0.05 μm or more, formation of the photosensitive resin layer 3 by coating becomes easy. When the thickness is 50 μm or less, the light transmittance is good, sufficient sensitivity can be obtained, and the photocuring property of the photosensitive layer after transfer can be made excellent.

  As the cover film 5, what was illustrated as a polymer film which can be used as the support film 1 is mentioned. At that time, the support film 1 is preferably adjusted by film thickness control, surface treatment, etc. of the support film and the cover film so that the support film 1 is peeled off with priority over the cover film 5.

  The thickness of the cover film 5 is preferably 10 to 200 μm, more preferably 15 to 150 μm, and particularly preferably 15 to 100 μm.

  The haze value of the cover film 5 is preferably 0.01 to 5.0%, more preferably 0.01 to 3.0%, from the viewpoint of improving sensitivity and resolution. More preferably, it is -2.0%, and it is especially preferable that it is 0.01-1.0%. The haze value can be measured according to JIS K 7105, and can be measured with a commercially available turbidimeter such as NDH-1001DP (trade name, manufactured by Nippon Denshoku Industries Co., Ltd.).

  Regarding the photosensitive conductive film according to the present embodiment, the manufacturing method in which the conductive layer and the photosensitive resin layer are sequentially applied and formed on the support film has been described, but the manufacturing method of the photosensitive conductive film is not limited thereto. FIG. 2 is a schematic cross-sectional view showing an example of a method for producing a photosensitive conductive film. In the manufacturing method shown in FIG. 2, the conductive layer 2 is formed on the first film (support film) 1 and the photosensitive resin layer 3 is separately formed on the second film (cover film) 5. Features. A photosensitive conductive film is manufactured by laminating the two films obtained in this manner with a roller 50 so that the conductive layer 2 and the photosensitive resin layer 3 are laminated. According to this manufacturing method, since the conductive layer and the photosensitive resin layer are separately formed, the structure in each layer (for example, the network structure of the conductive layer) is controlled as compared with the manufacturing method in which the solution is applied in layers. Becomes easier. At this time, it is preferable to laminate the film on which the conductive layer is formed and / or the film on which the photosensitive resin layer is formed at 60 to 130 ° C., and the pressure is about 0.2 to 0.8 MPa. Is preferred.

  In the present embodiment, the laminate (photosensitive layer 4) of the conductive layer 2 and the photosensitive resin layer 3 preferably has a minimum light transmittance of 80% or more in a wavelength region of 450 to 650 nm, and 85% or more. It is more preferable that When the photosensitive layer 4 satisfies such a condition, it is easy to increase the brightness in a display panel or the like. Further, when the total film thickness of both the conductive layer 2 and the photosensitive resin layer 3 constituting the photosensitive layer 4 is 1 to 10 μm, the minimum light transmittance in a wavelength region of 450 to 650 nm is 80% or more. It is preferable that it is 85% or more. When the conductive layer and the photosensitive resin layer satisfy such conditions, it is easy to increase the brightness in a display panel or the like.

  The photosensitive conductive film may further have layers such as an adhesive layer and a gas barrier layer on the support film or the cover film, or on both films.

  The photosensitive conductive film can be stored, for example, in the form of a flat plate as it is or in the form of a roll wound around a cylindrical core.

  The core is not particularly limited as long as it is conventionally used. For example, plastic such as polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride resin, ABS resin (acrylonitrile-butadiene-styrene copolymer), etc. Is mentioned. Moreover, it is preferable to install an end face separator on the end face of the photosensitive conductive film wound up in a roll shape from the viewpoint of end face protection, and in addition, it is preferable to install a moisture-proof end face separator from the viewpoint of edge fusion resistance. Moreover, when packing a photosensitive conductive film, it is preferable to wrap and wrap in a black sheet with small moisture permeability.

<Method for forming conductive pattern>
FIG. 3 is a schematic cross-sectional view for explaining a method for forming a conductive pattern according to this embodiment. In the method of this embodiment, the above-described photosensitive conductive film 10 is laminated so that the support film 1 is peeled off and the conductive layer 2 is in close contact with the base material 20 (FIGS. 3A and 3B). And a patterning step of forming a conductive pattern by exposing and developing the photosensitive layer on the substrate (FIGS. 3C and 3D). The patterning step includes an exposure step (FIG. 3C) in which a predetermined portion of the photosensitive layer 4 having the cover film 5 is irradiated with actinic rays, and then a developing step (in which the cover film 5 is peeled off to develop the photosensitive layer 4). FIG. 3 (d)).

  As the substrate 20, a substrate such as a glass substrate or a plastic substrate such as polycarbonate can be used. The thickness of the base material 20 can be appropriately selected according to the purpose of use, and a film-like base material may be used. Examples of the film-like substrate include a polyethylene terephthalate film, a polycarbonate film, and a cycloolefin polymer film. As the base material 20, a substrate on which a transparent electrode or the like is already formed by ITO or the like can be used. The substrate 20 preferably has a minimum light transmittance of 80% or more in a wavelength region of 450 to 650 nm. When the base material 20 satisfies such a condition, it is easy to increase the brightness in a display panel or the like.

  The laminating step is performed, for example, by a method in which the support film 1 of the photosensitive conductive film 10 is removed, and then the conductive layer 2 side is pressure-bonded to a base material 20 such as a glass substrate while heating. In addition, it is preferable to laminate | stack this operation under pressure reduction from the viewpoint of adhesiveness and followable | trackability. The lamination of the photosensitive conductive film 10 is preferably performed by heating the conductive layer 2 and the photosensitive resin layer 3 and / or the substrate 20 to 70 to 130 ° C., and these conditions are not particularly limited. In addition, if the conductive layer 2 and the photosensitive resin layer 3 are heated to 70 to 130 ° C. as described above, it is not necessary to pre-heat the base material 20 in advance. Twenty pre-heat treatments can also be performed.

The lamination of the photosensitive conductive film 10 preferably has a pressure bonding pressure of about 0.1 to 1.0 MPa (about 1 to 10 kgf / cm ² ), more preferably 0.2 to 0.8 MPa. .

  In the exposure step, the photosensitive resin layer is cured by irradiating actinic rays, and the conductive layer is fixed by the cured product, whereby a conductive pattern is formed on the substrate. Examples of the exposure method in the exposure step include a method of irradiating actinic rays L in an image form through a negative or positive mask pattern called an artwork (mask exposure method). As the light source of actinic light, a known light source, for example, a carbon arc lamp, a mercury vapor arc lamp, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a xenon lamp, or the like that effectively emits ultraviolet light, visible light, or the like is used. Further, an Ar ion laser, a semiconductor laser, or the like that effectively emits ultraviolet light, visible light, or the like is also used. Furthermore, what effectively radiates | emits visible light, such as a photographic flood light bulb and a solar lamp, is also used. Alternatively, a method of irradiating actinic rays in an image by a direct drawing method using a laser exposure method or the like may be employed.

The exposure amount of the actinic ray L at this time varies depending on the apparatus to be used, the composition of the photosensitive resin composition, etc., but is preferably 5 to 1000 mJ / cm ² , more preferably 10 to 200 mJ / cm ² . . In terms of excellent photocurability, it is preferably 10 mJ / cm ² or more, and in terms of resolution, it is preferably 200 mJ / cm ² or less. By setting it to 1000 mJ / cm ² or less, discoloration of the photosensitive layer can be suppressed.

  When the cover film 5 on the photosensitive resin layer is transparent to the active light L, the active light L can be irradiated through the cover film 5, and when the cover film 5 is light-shielding, After removing the film 5, the photosensitive resin layer is irradiated with actinic rays.

  As described above, the photosensitive conductive film used in the present invention is selected from the film thickness and material of the support film 1 and the cover film 5 and the surface treatment so that the support film is separated before the cover film. What is necessary is just to adjust the adhesive strength of both films by such as.

  Moreover, when the base material 20 is transparent with respect to the actinic ray L, it is possible to irradiate actinic rays from the base material side through the base material, but in terms of resolution, the photosensitive resin layer from the photosensitive resin layer side. It is preferable to irradiate actinic rays.

  According to the method for forming a conductive pattern of the present embodiment, the photosensitive layer 4 is provided on the substrate 20 more simply by providing the photosensitive layer 4 by laminating the separately prepared photosensitive conductive film 10 to the substrate 20. Therefore, productivity can be improved. Moreover, according to the method for forming a conductive pattern of the present invention, a transparent conductive pattern can be easily formed on a base material such as a glass substrate or a plastic substrate.

  In the development process (process for forming a conductive pattern), the unexposed part (part other than the exposed part) of the photosensitive layer is removed. Specifically, when the transparent cover film 5 is present on the photosensitive layer, the cover film 5 is first removed, and then the unexposed portion of the photosensitive layer is removed by wet development. Thereby, the conductive layer 2a containing a conductive fiber remains under the resin cured layer 3b having a predetermined pattern, and a conductive pattern is formed. In this way, as shown in FIG. 3D, a conductive pattern substrate 40 having a conductive pattern is obtained.

  The wet development is performed by a known method such as spraying, rocking dipping, brushing or scraping using a developer corresponding to a photosensitive resin such as an alkaline aqueous solution, an aqueous developer, or an organic solvent developer.

  As the developer, a safe and stable solution having good operability such as an alkaline aqueous solution is used. Examples of the base of the alkaline aqueous solution include hydroxides of alkali metals such as lithium, sodium and potassium (alkali hydroxide); carbonates or bicarbonates such as lithium, sodium, potassium and ammonium (alkali carbonate); lithium and sodium Borate or polyborate such as potassium and ammonium; alkali metal phosphates such as potassium phosphate and sodium phosphate; alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate.

  As alkaline aqueous solution used for development, 0.1-5 mass% sodium carbonate aqueous solution, 0.1-5 mass% potassium carbonate aqueous solution, 0.1-5 mass% sodium hydroxide aqueous solution, 0.1-5 mass% A sodium borate aqueous solution or the like is preferable. Moreover, it is preferable to make pH of the alkaline aqueous solution used for image development into the range of 9-11, and the temperature is adjusted according to the developability of the photosensitive resin layer. In the alkaline aqueous solution, a surfactant, an antifoaming agent, a small amount of an organic solvent for accelerating development, and the like may be mixed.

  Further, an aqueous developer composed of water or an aqueous alkali solution and one or more organic solvents can be used. Here, as the base contained in the alkaline aqueous solution, in addition to the above-mentioned bases, borax, sodium metasilicate, tetramethylammonium hydroxide, ethanolamine, ethylenediamine, diethylenetriamine, 2-amino-2-hydroxymethyl-1, 3 -Propanediol, 1,3-diaminopropanol-2, morpholine and the like.

  Examples of the organic solvent include methyl ethyl ketone, acetone, ethyl acetate, alkoxyethanol having an alkoxy group having 1 to 4 carbon atoms, ethyl alcohol, isopropyl alcohol, butyl alcohol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether. It is done. These are used individually by 1 type or in combination of 2 or more types.

  The aqueous developer preferably has an organic solvent concentration of 2 to 90% by mass, and the temperature can be adjusted according to the developability. Furthermore, the pH of the aqueous developer is preferably as small as possible within a range where the development of the photosensitive resin layer can be sufficiently performed, preferably pH 8 to 12, and more preferably pH 9 to 10. In addition, a small amount of a surfactant, an antifoaming agent, or the like can be added to the aqueous developer.

  Examples of the organic solvent developer include 1,1,1-trichloroethane, N-methylpyrrolidone, N, N-dimethylformamide, cyclohexanone, methyl isobutyl ketone, and γ-butyrolactone. These organic solvents preferably add water in the range of 1 to 20% by mass in order to prevent ignition. The above developing solutions may be used in combination of two or more as required.

  Examples of the development method include a dip method, a paddle method, a high pressure spray method, a spray method, brushing, and slapping. Among these, it is preferable to use a high-pressure spray system from the viewpoint of improving the resolution.

In the method for forming a conductive pattern of the present embodiment, the conductive pattern may be further cured by heating at about 60 to 250 ° C. or exposure at about 0.2 to 10 J / cm ² as necessary after development. Good.

  Thus, according to the method for forming a conductive pattern according to the present embodiment, a transparent conductive pattern can be easily formed on a substrate such as a glass substrate or a plastic substrate without forming an etching resist like an inorganic film such as ITO. Can be formed.

  The conductive pattern substrate of the present invention is obtained by the conductive pattern forming method described above. The surface resistivity of the conductive pattern is preferably 2000Ω / □ or less, more preferably 1000Ω / □ or less, and particularly preferably 500Ω / □ or less from the viewpoint that it can be effectively used as a transparent electrode or the like. . The surface resistivity can be adjusted by, for example, the concentration of the conductive fiber dispersion, the coating amount, and the like.

  In the conductive pattern substrate of the present invention, the minimum light transmittance in the wavelength region of 450 to 650 nm is preferably 80% or more, and more preferably 85% or more. When the conductive pattern substrate 40 satisfies such a condition, visibility on a display panel or the like is improved.

  The method for forming a conductive pattern of the present invention can be preferably used for forming a transparent electrode of a capacitive touch panel, for example. FIG. 4 is a plan view showing an example of a capacitive touch panel in which the transparent electrode (X position coordinate) 103 and the transparent electrode (Y position coordinate) 104 exist on the same plane, and FIG. FIG. 6 is a partial cross-sectional view taken along line VI-VI in FIG. The capacitive touch panel includes a transparent electrode 103 that detects a change in capacitance and uses X position coordinates, and a transparent electrode 104 uses Y position coordinates on a transparent substrate 101. Each of the transparent electrodes 103 and 104 having the X and Y position coordinates has lead-out wirings 105a and 105b for connecting to a control circuit of a driver element circuit (not shown) that controls an electrical signal as a touch panel. .

  An insulating film 106 is provided at a portion where the transparent electrode (X position coordinate) 103 and the transparent electrode (Y position coordinate) 104 intersect. The insulating film is selected from materials having electrical insulating properties, transparency, and development resistance. Examples of such a material include a thin and transparent photosensitive film.

  A method for manufacturing a capacitive touch panel according to the method for forming a conductive pattern of the present invention will be described. First, a transparent electrode (X position coordinate) 103 is formed on the transparent substrate 101. Specifically, the photosensitive conductive film is laminated so that the conductive layer is in contact with the transparent substrate 101 (lamination process). The transferred photosensitive layer (conductive layer and photosensitive resin layer) is irradiated with actinic rays in a desired shape through a light-shielding mask (exposure process). Thereafter, the light-shielding mask is removed, the support film is further peeled off, and development is performed, whereby the unexposed portion of the photosensitive layer is removed and a conductive pattern is formed (development process). A transparent electrode 103 for detecting the X position coordinate is formed by this conductive pattern.

  Subsequently, a transparent electrode (Y position coordinate) 104 is formed. An insulating film 106 is provided on a part of the transparent electrode 103 formed by the above process (for example, a part where the transparent electrode 103 and the transparent electrode 104 are to intersect), and a new photosensitive conductive film is formed on the transparent substrate 101. And the transparent electrode 104 for detecting the Y position coordinate is formed by the same operation as described above. By forming a transparent electrode by the method for forming a conductive pattern according to the present invention, the transparent electrode (X position coordinate) 103 and the transparent electrode (Y position coordinate) 104 can be formed on the same plane. In addition, since the conductive pattern is formed on the transparent substrate 101 side, when the lead-out wirings 105a and 105b are formed, it is easy to achieve conduction between the formed conductive pattern and the lead-out wiring.

  Next, lead wires 105 a and 105 b for connecting to an external circuit are formed on the surface of the transparent substrate 101. The lead-out wiring can be formed by screen printing using a conductive paste material containing, for example, flaky silver or the like.

  In the method of manufacturing the capacitive touch panel, one transparent electrode (for example, the transparent electrode (X position coordinate) 103) and the lead-out wirings 105a and 105b are formed by a known method using a transparent conductive material. It can be formed in advance on 101. Even in this case, the transparent electrode (X position coordinate) 103 and the transparent electrode (Y position coordinate) 104 can be formed in the same plane, and an excellent conductive pattern can be obtained by adhesion and resolution. Can do. In addition, by performing patterning by the above-described process, it is possible to form a conductive pattern of the bridged transparent electrode (Y position coordinate) 104.

  Moreover, the manufacturing method of the capacitive touch panel by the method for forming a conductive pattern according to the present invention is not limited to the above method. For example, a substrate in which a transparent electrode (X position coordinate) 103 and a part of a transparent electrode to be detected later as a transparent electrode 104 are formed on the transparent substrate 101 in advance by a known method using a transparent conductive material. May be used. FIG. 7 is a diagram for explaining an example of a method for manufacturing a capacitive touch panel in which transparent electrodes are present on the same plane, and (a) is a partially cutaway perspective view showing a substrate provided with transparent electrodes. (B) is a partially cutaway perspective view showing the obtained capacitive touch panel. FIG. 8 is a diagram for explaining an example of a method for manufacturing a capacitive touch panel in which transparent electrodes exist on the same plane.

  First, as shown in FIG. 7A and FIG. 8A, a substrate on which a transparent electrode (X position coordinate) 103 and a part 104a of the transparent electrode are formed in advance is prepared. An insulating film 106 is provided on a part (a part sandwiched by part 104a of the transparent electrode) (FIG. 8B). Thereafter, a photosensitive conductive film is laminated on the substrate, and a conductive pattern is formed by the same method as the exposure step and the development step described above. With this conductive pattern, the bridge portion 104b of the transparent electrode can be formed (FIG. 8C). By this transparent electrode bridge portion 104 b, a part of the transparent electrodes 104 a formed in advance can be connected to each other, and a transparent electrode (Y position coordinate) 104 is formed.

  The previously formed transparent electrode may be formed by a known method using ITO or the like, for example.

  The lead-out wirings 105a and 105b can be formed by a known method using a metal such as Cu or Ag in addition to the transparent conductive material. In the method for forming a conductive pattern of the present invention, a substrate on which lead-out wirings 105a and 105b are previously formed may be used. When such a substrate is used, according to the conductive pattern forming method of the present invention, the transparent electrode (Y position coordinate) is insulated from the transparent electrode (X position coordinate) while being directly connected to the lead wiring. It is possible to form the conductive pattern substrate more easily.

  Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited thereto.

<Preparation of conductive fiber dispersion (silver fiber dispersion)>
[Preparation of silver fiber by polyol method]
In a 2000 mL three-necked flask, 500 mL of ethylene glycol was placed and heated to 160 ° C. with an oil bath while stirring with a magnetic stirrer under a nitrogen atmosphere. A solution prepared by dissolving ₂ mg of PtCl ₂ separately prepared in 50 mL of ethylene glycol was added dropwise thereto. After 4 to 5 minutes, a solution in which 5 g of AgNO ₃ was dissolved in 300 mL of ethylene glycol and a solution in which 5 g of polyvinylpyrrolidone having a weight average molecular weight of 40,000 (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 150 mL of ethylene glycol were respectively obtained. From the dropping funnel in 1 minute, and then stirred at 160 ° C. for 60 minutes.

  The reaction solution was allowed to stand at 30 ° C. or lower, diluted 10 times with acetone, centrifuged at 2000 rpm for 20 minutes with a centrifuge, and the supernatant was decanted. Acetone was added to the precipitate, stirred, and then centrifuged under the same conditions as described above, and acetone was decanted. Then, it centrifuged twice similarly using distilled water, and obtained the silver fiber. When the obtained silver fiber was observed with an optical microscope, the fiber diameter (diameter) was about 5 nm, and the fiber length was about 5 μm.

[Preparation of silver fiber dispersion]
The conductive fiber dispersion 1 was obtained by dispersing 0.2% by mass of the silver fiber obtained above and 0.1% by mass of dodecyl-pentaethylene glycol in pure water.

<Preparation of solution of photosensitive resin composition>
[Synthesis of acrylic resin]
In a flask equipped with a stirrer, reflux condenser, thermometer, dropping funnel and nitrogen gas introduction tube, a mixture of methyl cellosolve and toluene (methyl cellosolve / toluene = 3/2 (mass ratio), hereinafter “solution s 400 g) was added, stirred while blowing nitrogen gas, and heated to 80 ° C. On the other hand, a solution in which 100 g of methacrylic acid, 250 g of methyl methacrylate, 100 g of ethyl acrylate and 50 g of styrene are mixed with 0.8 g of azobisisobutyronitrile as an initiator (hereinafter referred to as “solution a”). Prepared. Next, the solution a was added dropwise to the solution s heated to 80 ° C. over 4 hours, and then kept at 80 ° C. with stirring for 2 hours. Further, a solution obtained by dissolving 1.2 g of azobisisobutyronitrile in 100 g of the solution s was dropped into the flask over 10 minutes. And the solution after dripping was heat-retained at 80 degreeC for 3 hours, stirring, Then, it heated at 90 degreeC over 30 minutes. The mixture was kept at 90 ° C. for 2 hours and then cooled to obtain a binder polymer solution. Acetone was added to this binder polymer solution to prepare a non-volatile component (solid content) of 50% by mass to obtain a binder polymer solution as component (A). The weight average molecular weight of the obtained binder polymer was 80000 in terms of standard polystyrene conversion by GPC. This was designated as acrylic polymer A. In addition, the measurement conditions of GPC which measured the weight average molecular weight are as follows.

[GPC measurement conditions]
Model: Hitachi L6000 (manufactured by Hitachi, Ltd.)
Detection: L3300RI (manufactured by Hitachi, Ltd.)
Column: Gelpack GL-R440 + GL-R450 + GL-R400M (manufactured by Hitachi Chemical Co., Ltd.)
Column specifications: Diameter 10.7mm x 300mm
Solvent: THF (tetrahydrofuran)
Sample concentration: 120 mg of a resin solution having a NV (nonvolatile content concentration) of 50% by mass was collected and dissolved in 5 mL of THF. Injection amount: 200 μL
Pressure: 4.9 MPa
Flow rate: 2.05 mL / min

[Preparation of photosensitive resin composition solution]
The materials shown in Table 1 were blended in the blending amounts (unit: parts by mass) shown in the same table to prepare a solution of the photosensitive resin composition.

<Preparation of photosensitive conductive film>
Example 1
The conductive fiber dispersion 1 is uniformly applied at 25 g / m ² on a 16 μm-thick polyethylene terephthalate film (PET film, manufactured by Teijin Ltd., trade name: G2-16), which is a support film, at 100 ° C. The hot air convection dryer was dried for 10 minutes, and a conductive layer containing conductive fibers was formed on the support film by pressurizing at a linear pressure of 1 MPa at room temperature (25 ° C.). In addition, when measured by a scanning electron micrograph, the film thickness after drying of the conductive layer was about 0.1 μm.

  Next, the photosensitive resin composition solution was uniformly applied onto a separately prepared 50 μm thick polyethylene terephthalate film (PET film, manufactured by Teijin Ltd., trade name: G2-50), and hot air at 100 ° C. The photosensitive resin layer was formed by drying for 10 minutes with a convection dryer. In addition, when measured with the scanning electron micrograph, the film thickness after drying of the photosensitive resin layer was 5 μm.

  The PET film formed with the conductive layer and the PET film formed with the photosensitive resin layer obtained as described above are arranged so that the conductive layer and the photosensitive resin layer face each other at 120 ° C. and 0.4 MPa. The objective photosensitive conductive film was produced by laminating under the conditions described above.

<Measurement of surface resistivity and light transmittance>
A polycarbonate substrate having a thickness of 1 mm was heated to 80 ° C., and the support layer (PET film having a thickness of 16 μm) of the photosensitive conductive film obtained in Example 1 was peeled off from the surface of the polycarbonate substrate. Were laminated under the conditions of 120 ° C. and 0.4 MPa. After lamination, when the substrate is cooled and the temperature of the substrate reaches 23 ° C., an exposure machine (trade name: EXM-, manufactured by Oak Manufacturing Co., Ltd.) having an ultrahigh pressure mercury lamp from the cover film (PET film having a thickness of 50 μm) side. 1201), the photosensitive layer (conductive layer and photosensitive resin layer) was irradiated with light at an exposure amount of 1000 mJ / cm ² . After exposure, the film was allowed to stand at room temperature (25 ° C.) for 15 minutes, and then the PET film as the cover film was peeled off to form a conductive film containing silver fibers on the polycarbonate substrate to obtain a conductive film substrate. . About the obtained electrically conductive film board | substrate, the surface resistivity and the minimum light transmittance in a 450-650 nm wavelength range were evaluated. The surface resistivity of the conductive film measured using the following measuring apparatus was 100Ω / □, and the minimum light transmittance (including the substrate) in the wavelength region of 450 to 650 nm was 90%.

[Measurement of surface resistivity]
The measurement was performed using a non-contact type surface resistance meter (EC-80P, manufactured by Napson Corporation).

[Measurement of light transmittance]
Using a spectrophotometer (trade name “U-3310”, manufactured by Hitachi High-Technologies Corporation), the minimum light transmittance in a wavelength region of 450 to 650 nm was measured.

<Formation of conductive pattern>
A polycarbonate substrate having a thickness of 1 mm is heated to 80 ° C., and the photosensitive conductive film obtained in Example 1 is placed on the surface of the polycarbonate substrate with the conductive layer and the polycarbonate substrate facing each other while peeling the support film. Lamination was performed at a temperature of 0.4 MPa. After lamination, when the substrate is cooled and the temperature of the substrate reaches 23 ° C., a photomask having a wiring pattern with a line width / space width of 200/200 μm and a length of 100 mm is formed on the surface of the PET film as the cover film. Adhered. The photosensitive layer (conductive layer and photosensitive resin layer) was irradiated with light at an exposure amount of 30 mJ / cm ² using an exposure machine (trade name: EXM-1201, manufactured by Oak Manufacturing Co., Ltd.) having an ultra-high pressure mercury lamp. .

  After the exposure, the film was allowed to stand at room temperature (25 ° C.) for 15 minutes, and then the PET film as the cover film was peeled off and developed by spraying a 1% by mass aqueous sodium carbonate solution at 30 ° C. for 30 seconds. After development, a conductive pattern containing silver fibers having a line width / space width of about 200/200 μm was formed on a polycarbonate substrate. It was confirmed that each conductive pattern was well formed.

  According to the method for forming a conductive pattern of the present invention, it is possible to form a conductive pattern with sufficient resolution with sufficient adhesion to a substrate and a sufficiently low surface resistivity. In addition, the connection terminals provided on the substrate surface and the conductive pattern can be easily connected.

DESCRIPTION OF SYMBOLS 1 ... 1st film (support film), 2 ... Conductive layer, 2a ... Conductive pattern, 3 ... Photosensitive resin layer, 3b ... Resin hardened layer, 4 ... Photosensitive layer, 5 ... Second film (cover film), DESCRIPTION OF SYMBOLS 10 ... Photosensitive conductive film, 20 ... Base material, 101 ... Transparent substrate, 103 ... Transparent electrode (X position coordinate), 104 ... Transparent electrode (Y position coordinate), 104a ... A part of transparent electrode, 104b ... Transparent electrode Bridge part, 105a, 105b ... lead-out wiring, 106 ... insulating film.

Claims (4)

A method for forming a conductive pattern including a cured resin layer and a conductive layer on a substrate,
A photosensitive conductive film comprising a support film, a conductive layer containing conductive fibers, and a photosensitive resin layer containing a photosensitive resin in this order is prepared so that the conductive layer is in close contact with the substrate. A laminating step of laminating the conductive layer and the photosensitive resin layer;
A patterning step of forming a conductive pattern by exposing and developing the photosensitive resin layer on the substrate; and
A method for forming a conductive pattern. The method for forming a conductive pattern according to claim 1, wherein the conductive fiber is a silver fiber. The method for forming a conductive pattern according to claim 1, wherein the conductive fiber is a carbon nanotube. The method for forming a conductive pattern according to claim 1, wherein the conductive pattern is a transparent electrode of a wiring or a capacitive touch panel.

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