JP2019096416A - Method for producing conductive material - Google Patents

Abstract

To provide a method for producing a conductive material that makes it possible to produce a conductive material having high conductivity.SOLUTION: A conductive material precursor having, on a support, a physical development nucleus layer and a silver halide emulsion layer at least in the stated order, is exposed and then developed with a developer containing an organic phosphonic acid chelator.SELECTED DRAWING: None

Description

  The present invention relates to a method of manufacturing a conductive material that can be used for applications such as touch panels, electromagnetic wave shielding materials, antenna circuits, electronic circuits and the like.

  In electronic devices such as smartphones, personal digital assistants (PDAs), notebook PCs, tablet PCs, OA devices, medical devices, and car navigation systems, touch panel sensors are widely used as input means for these displays.

  Touch panel sensors include an optical method, an ultrasonic method, a resistive film method, a surface capacitance method, a projected capacitance method, etc. depending on the position detection method, and in the display application described above, the resistive film method and the projection type The capacitance method is preferably used. The resistive film type touch panel sensor has a structure in which two conductive materials having a light transmitting conductive layer on a transparent support are used and these conductive materials are disposed opposite to each other via a dot spacer. The light transmitting conductive layers are in contact with each other by applying a force to one point, and the position to which the force is applied is measured by measuring the voltage applied to each light transmitting conductive layer through the other light transmitting conductive layer. Detection of On the other hand, a projected capacitive touch panel uses one conductive material having two light transmission conductive layers or two conductive materials having one light transmission conductive layer, a finger or the like Changes in capacitance between the light-transmissive conductive layers when the light source is brought close to each other, and detection of the position where the finger approaches is detected. The latter is particularly widely used in smartphones, tablet PCs, and the like, because it is excellent in durability because it has no movable part and can simultaneously detect multiple points.

As the conductive material having the light-transmissive conductive layer, a conductive film made of tin oxide (SnO ₂ ), indium tin oxide (ITO), zinc oxide (ZnO) or the like is vacuum-deposited on a light-transmissive support, sputtering, It is well known that it is provided by a dry process such as an ion plating method.

  In addition to the above-described dry process, a conductive material having a light-transmissive conductive layer formed by a wet process using a network structure of conductive polymer, carbon nanotubes, and metal fine particles such as metal nanowires is also proposed. .

  At present, the mainstream of the light transmitting conductive layer is the ITO conductive film. However, since the ITO conductive film has a large refractive index and a large surface reflection of light, it has a problem that the total light transmittance decreases, and because the flexibility is low, a crack is generated when the ITO conductive film is bent and the electric resistance value There was a problem that In addition, there are concerns about the exhaustion of indium used and high production costs, and a conductive material having a light-transmissive conductive layer formed by the above-mentioned wet process is being considered as a substitute material.

  In recent years, a method has also been proposed in which a silver halide photosensitive material is used as a conductive material precursor, and a mesh-like metallic silver fine line pattern made of metallic silver fine lines is formed to form a light transmitting conductive layer. For example, a method of forming a reticulated metallic silver fine wire pattern on a support using a direct development method is disclosed in WO 2001/51276 Pamphlet (Patent Document 1) and JP-A 2004-221564 (Patent Document 2) For example, Japanese Patent Application Laid-Open No. 2007-59270 (Patent Document 3) discloses a method of forming a reticulated metal silver fine wire pattern on a support using a curing and developing method. In addition, in JP-A-2003-77350 (Patent Document 4), JP-A-2005-250169 (Patent Document 5), etc., a conductive material having a physical development nucleus layer and a silver halide emulsion layer at least in this order on a support A silver salt diffusion transfer method is disclosed in which a precursor is reacted with a soluble silver salt forming agent and a reducing agent in an alkaline solution to form a reticulated metallic silver fine line pattern on a support. In particular, according to the silver salt diffusion transfer method, a thin wire made of silver, which has the highest conductivity among metals, can be easily formed with good reproducibility, so that a conductive material having both high transmittance and high conductivity can be formed. . Furthermore, the light transmitting conductive layer obtained by this method has the advantage of being more flexible and resistant to bending than an ITO conductive film, and is suitable for forming on a flexible support.

  However, in the light transmitting conductive layer obtained by the method described above, there is a problem that the metal silver fine wire portion does not transmit light, so that a mesh-like metal silver fine wire pattern is easily visible. In order to improve this, it is necessary to further thin the metal silver fine wires, but if the wires are simply made thin, the resistance value of the metal silver fine wires increases, so the sensitivity of the touch panel sensor is lowered. That is, a method for producing a conductive material having higher conductivity has been desired.

  On the other hand, in JP 2010-108877 A (patent document 6), in a method of producing a transparent conductive film obtained by exposing and developing a photosensitive material having a silver salt-containing layer on a support, the developer is used. Organic phosphonic acid and amino phosphonic acid are described as an example of the contained organic and inorganic chelating agent.

WO 2001/51276 pamphlet Japanese Patent Application Publication No. 2004-221564 JP 2007-59270 A Japanese Patent Application Publication No. 2003-77350 JP 2005-250169 A Unexamined-Japanese-Patent No. 2010-108877

  An object of the present invention is to provide a method for producing a conductive material capable of producing a conductive material having high conductivity.

The above-mentioned object of the present invention is achieved by the following invention.
(1) A conductive material precursor having at least a physical development nucleus layer and a silver halide emulsion layer in this order exposed on a support and then developed with a developer containing an organic phosphonic acid chelating agent. Method of manufacturing conductive material.

  According to the present invention, it is possible to provide a method of producing a conductive material capable of producing a conductive material having high conductivity.

  Hereinafter, the present invention will be described. In the method for producing a conductive material according to the present invention, after a conductive material precursor having a physical development nucleus layer and a silver halide emulsion layer at least in this order exposed on a support, a developer containing an organic phosphonic acid chelating agent is used. develop.

<Organic phosphonic acid chelating agent>
The organic phosphonic acid chelating agent used in the present invention will be described. The phosphonic acid chelating agent means a compound having at least one phosphorus-containing ligand among compounds having two or more ligands capable of forming a chelate compound by binding to a metal ion. The organic phosphonic acid chelating agent used in the present invention means a phosphonic acid chelating agent having a carbon-phosphorus bond in the molecular structure, and is distinguished from an inorganic phosphonic acid chelating agent having no carbon-phosphorus bond in the molecular structure Ru. Specific examples of the organic phosphonic acid chelating agent include the following compounds, but the present invention is not limited thereto. Examples of organic phosphonic acid chelating agents include ethylenediamine tetramethylene phosphonic acid, nitrilotris methylene phosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, diethylene triamine pentamethylene phosphonic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid And phytic acid can be used. Among these, 1-hydroxyethylidene-1,1-diphosphonic acid and 2-phosphonobutane-1,2,4-tricarboxylic acid are preferable. These organic phosphonic acid chelating agents may be used in the form of salts such as alkali metal salts and ammonium salts.

  In the present invention, the organic phosphonic acid chelating agent may be used alone or in combination of two or more.

  A commercial item can be used as an organic phosphonic acid chelating agent as described above. For example, as an organic phosphonic acid chelating agent, Dayquest (registered trademark) 2000 commercially available from Italmatch Japan Co., Ltd., Dayquest 2006, Dayquest 2010, Dayquest 2016, Dayquest 2046, Dayquest 2060S, Dayquest 7000 And the like, and Chelest® PH-210, Chelyst PH-214, Chelyst PH-320, Chelyst PH-430, Chelyst PH-540, etc., which are commercially available from Chelest Co., Ltd., may be mentioned and used. can do.

<Developer>
The developer used in the method for producing a conductive material of the present invention contains the above-mentioned organic phosphonic acid chelating agent. The content of the organic phosphonic acid chelating agent in the developer is preferably 0.1 to 50 g / L, and more preferably 1 to 30 g / L because the conductive material obtained is excellent in conductivity.

  When each constituent layer of the conductive material precursor used in the present invention contains a developing agent, the developing solution does not have to contain the developing agent, and the developing solution can reduce silver halide having a latent image nucleus Containing an alkaline agent. Examples of the alkaline agent include potassium hydroxide, sodium hydroxide, lithium hydroxide, tribasic sodium phosphate, and various amine compounds. 10 or more are preferable and, as for pH of a developing solution, the range of 11-14 is more preferable.

  When the conductive material precursor does not contain a developing agent, the developing solution used in the present invention contains a developing agent. As such a developing agent, for example, polyhydroxybenzenes such as hydroquinone, catechol, pyrogallol, methylhydroquinone and chlorohydroquinone, 1-phenyl-4,4-dimethyl-3-pyrazolidone, 1-phenyl-3-pyrazolidone, 1-phenyl-3-pyrazolidone 3-p-Tolyl-3-pyrazolidone, 1-phenyl-4-methyl-3-pyrazolidone, 1-phenyl-4-methyl-4-hydroxymethyl-3-pyrazolidone, 1-p-chlorophenyl-3-pyrazolidone and the like Pyrazolidones, paramethylaminophenol, paraaminophenol, parahydroxyphenylglycine, paraphenylenediamine, ascorbic acid and the like may be mentioned, and two or more of these may be used in combination. The content of the developing agent is preferably 1 to 100 g / L.

  The developer may further contain a preservative represented by sodium sulfite or potassium sulfite, and a buffer represented by carbonate or phosphate for keeping the pH of the developer in a preferred range. preferable. Further, an antifogging agent may be contained so as to prevent reduction of silver halide grains having no latent image nucleus, such as bromide ion, benzimidazole, benzotriazole, 1-phenyl-5-mercaptotetrazole and the like.

  In the present invention, the developer preferably contains a soluble silver complex salt forming agent in order to perform diffusion transfer development. As the soluble silver complex salt forming agent, specifically, thiosulfates such as ammonium thiosulfate and sodium thiosulfate, thiocyanate such as sodium thiocyanate and ammonium thiocyanate, 1,10-dithia-18-crown-6 , Thioethers such as 2,2'-thiodiethanol, oxazolidones, 2-mercaptobenzoic acid and derivatives thereof, cyclic imides such as uracil, alkanolamines, diamines, mesoionic properties described in JP-A-9-171257. Compounds, 5, 5-dialkylhydantoins, alkyl sulfones, and the like, “The Theory of the photographic Process (4th edition, p 474 to 475)”, T.F. H. Included are the compounds described in James. Among these soluble silver complexing agents, alkanolamines are particularly preferred. As the alkanolamine, for example, N- (2-aminoethyl) ethanolamine, diethanolamine, N-methylethanolamine, triethanolamine, N-ethyldiethanolamine, diisopropanolamine, ethanolamine, 4-aminobutanol, N, N- Examples include dimethyl ethanolamine, 3-aminopropanol, 2-amino-2-methyl-1-propanol and the like. These soluble silver complex salt forming agents can be used alone or in combination. The content of the soluble silver complexing agent is preferably 0.1 to 40 g / L, more preferably 1 to 20 g / L.

<Conductive material precursor>
The conductive material precursor used in the present invention will be described. In the present invention, the conductive material precursor has at least a physical development nucleus layer and a silver halide emulsion layer in this order on a support.

<Support>
The support of the conductive material precursor is not particularly limited, but when the conductive material of the present invention is used for applications requiring light transmission such as a touch panel sensor, it is particularly preferable that the support has light transmission. The light transmitting support includes polyolefin resins such as polyethylene and polypropylene, vinyl chloride resins such as polyvinyl chloride and vinyl chloride copolymer, epoxy resin, polyarylate, polysulfone, polyether sulfone, polyimide, Various resin films such as fluorine resin, phenoxy resin, triacetyl cellulose, polyethylene terephthalate, polyimide, polyphenylene sulfide, polyethylene naphthalate, polycarbonate, acrylic resin, cellophane, nylon, polystyrene resin, ABS resin, quartz glass, alkali-free glass Glass etc. can be illustrated. From the viewpoint of transparency of the conductive material, the total light transmittance of the support is preferably 60% or more, particularly preferably 70% or more, and from the same viewpoint, the haze of the support is preferably 0 to 3%, particularly preferably Is 0 to 2%. The thickness of the support is preferably 10 to 300 μm from the viewpoint of handleability and transparency. The support may have a known layer such as an easily adhesive layer, a hard coat layer, an antireflective layer or an antiglare layer on at least one surface of the support.

Physical Development Core Layer
The physical development nucleus layer of the conductive material precursor contains at least physical development nuclei. As physical development nuclei, fine particles (particle size of about 1 to several tens of nm) made of heavy metal or its sulfide are used. Examples thereof include metal colloids such as gold and silver, and metal sulfides obtained by mixing sulfides with water-soluble salts such as palladium and zinc. The content of physical development nuclei in the physical development nucleus layer is 0.01 in terms of solid content, from the viewpoint of the adhesion between the metallic silver fine wires and the physical development nucleus layer of the conductive material obtained by the method of manufacturing the conductive material of the present invention -10 mg / m < ² > is preferable. The physical development nucleus layer may be provided directly on the support, or may be provided on another layer of the support such as the easy adhesion layer.

  The physical development nucleus layer preferably contains a water-soluble polymer compound or a water-insoluble polymer compound as a binder in addition to the physical development nucleus described above, and more preferably contains a water-soluble polymer compound.

  The water-soluble polymer compound is not limited, and known compounds can be used. Specifically, gelatin, proteins such as casein and albumin, polysaccharides such as starch and dextrin, cellulose and derivatives thereof (eg carboxyl methyl cellulose, hydroxyl propyl cellulose, methyl cellulose etc), alginic acid, carrageenan, guar gum, xanthan gum, fucoidan, chitosan, Hyaluronic acid, polyethylene oxide, polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl methyl ether, polyacrylamide, polyethylene imine, polyallylamine, polyvinyl amine, polylysine, polyacrylic acid, and graft polymerization polymers thereof can be exemplified. In addition, compounds modified by known methods such as succinated gelatin can also be used.

  Among the above-mentioned water-soluble polymer compounds, it is particularly preferable to contain a water-soluble polymer compound having an amino group such as polyethyleneimine and polyallylamine. The content of the water-soluble polymer compound or the water-insoluble polymer compound contained in the physical development nucleus layer is preferably 10 to 50000% by mass with respect to the physical development nucleus.

  When the physical development nucleus layer contains a water-soluble polymer compound, it is preferable to contain a crosslinking agent in order to crosslink the water-soluble polymer compound. The crosslinking agent is not particularly limited, and known crosslinking agents can be used. Specifically, organometallic compounds such as tetraisopropyl titanate, titanium acetylacetonate, titanium lactate, normal butyl zirconate, zirconium monoacetylacetonate, aluminum trisacetylacetonate, formaldehyde, glyoxal, glutaraldehyde, 3-methylglutaraldehyde , Aldehydes such as succinaldehyde and adipaldehyde, N-methylol compounds such as urea and ethylene urea, aldehyde equivalents such as mucochloric acid and 2,3-dihydroxy-1,4-dioxane, 2,4-dichloro-6 -Compounds having an active halogen such as -hydroxy-s-triazine salt and 2,4-dihydroxy-6-chloro-triazine salt, divinyl sulfone, divinyl ketone and N, N, N-triacryloyl hexene Hydrotriazines, compounds having two or more active three-membered ethyleneimino groups, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol Compounds having two or more epoxy groups in the molecule, such as diglycidyl ether, potassium aluminum sulfate (alum), and others “Chemical Reactions of Polymers” (Shin Ohkawara, 1972, Chemical Dojinsha), Chapter 2.6.7. Crosslinking agents described in chapters 5.2, 9.3 and the like can be exemplified. Among them, dialdehydes such as glyoxal, glutaraldehyde, 3-methylglutaraldehyde, succinaldehyde, adipaldehyde and the like, and compounds having two or more epoxy groups in the molecule are preferable. The crosslinking agent is preferably 0.1 to 80% by mass with respect to the water-soluble polymer compound contained in the physical development nucleus layer.

  The physical development nucleus layer may contain various known additives such as an organic solvent, a surfactant, an antifoaming agent, and a thickener in addition to the above-described compounds.

<Silver halide emulsion layer>
The silver halide emulsion layer contained in the conductive material precursor is a layer containing a silver halide emulsion in which silver halide grains are uniformly dispersed (emulsified), and therefore the silver halide emulsion layer is a silver halide grain Contains For the production of the silver halide grains, techniques used for silver halide photographic films relating to silver halide emulsions, photographic paper, films for printing plate making, emulsion masks for photomasks and the like can be used as they are.

  The silver halide grains contained in the silver halide emulsion layer may be any of silver chloride, silver bromide, silver iodide and silver fluoride, or a combination thereof. For the formation of silver halide grains, methods known in the art such as sequential mixing, reverse mixing, simultaneous mixing and the like are used. Above all, it is preferable to use a so-called controlled double jet method in which the pAg in the liquid phase in which the particles are formed is kept constant, which is one kind of simultaneous mixing method, from the viewpoint of obtaining silver halide grains with uniform grain size. In the present invention, the average grain size of silver halide grains is preferably 0.25 μm or less, particularly preferably 0.05 to 0.05 μm, from the viewpoint of conductivity of metal silver fine wires of the conductive material and the dispersion stability of silver halide grains. It is 0.2 μm. The silver halide grains contained in the silver halide emulsion layer preferably contain 80 mol% or more of silver chloride from the viewpoint of the conductivity of the metallic silver fine wires of the conductive material, and particularly preferably 90 mol% or more.

  The shape of the silver halide grain is not particularly limited, and may be, for example, various shapes such as spherical, cubic, tabular (hexagonal tabular, triangular tabular, rectangular tabular, etc.), octahedral, tetradecahedral, etc. Can be.

  A silver halide grain is a salt of a Group VIII metal element or a complex salt thereof, such as sulfite, lead salt, thallium salt, rhodium salt or complex salt thereof, iridium salt or complex salt thereof, as necessary in the process of formation or physical ripening You may coexist. Further, sensitization can be performed by various chemical sensitizers, and methods common in the art such as sulfur sensitization, selenium sensitization, and noble metal sensitization can be used alone or in combination.

  The silver halide grains can be spectrally sensitized as required. In addition, the silver halide grains do not necessarily have to be negative photosensitive, and may be silver halide grains having positive photosensitivity if necessary. The silver halide grains having positive photosensitivity can be prepared by the methods described in JP-A-8-171210 and JP-A-8-202041.

  The silver halide emulsion layer preferably contains a binder as a protective colloid for silver halide grains. Examples of the binder include water-soluble polymer compounds and water-insoluble polymer compounds.

  The water-soluble polymer compound is not limited, and known compounds can be used. Specifically, gelatin, proteins such as casein and albumin, polysaccharides such as starch and dextrin, cellulose and derivatives thereof (eg carboxyl methyl cellulose, hydroxyl propyl cellulose, methyl cellulose etc), alginic acid, carrageenan, guar gum, xanthan gum, fucoidan, chitosan, Hyaluronic acid, polyethylene oxide, polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl methyl ether, polyacrylamide, polyethylene imine, polyallylamine, polyvinyl amine, polylysine, polyacrylic acid, and graft polymerization polymers thereof can be exemplified. In addition, compounds modified by known methods such as succinated gelatin can also be used.

  Examples of the water-insoluble polymer compound include known homopolymers and copolymers. Homopolymers include vinyl acetate, vinyl chloride, styrene, methyl acrylate, butyl acrylate, methacrylonitrile, butadiene, isoprene and the like, and copolymers such as ethylene butadiene, styrene butadiene, styrene p-methoxystyrene , Styrene, vinyl acetate, vinyl acetate, vinyl chloride, vinyl acetate, diethyl maleate, methyl methacrylate, acrylonitrile, methyl methacrylate, butadiene, methyl methacrylate, styrene, methyl methacrylate, vinyl acetate, methyl methacrylate, vinylidene chloride, methyl acrylate, acrylonitrile , Methyl acrylate butadiene, methyl acrylate styrene, methyl acrylate vinyl acetate, acrylic acid butyl acrylate methyl Acrylate-vinyl chloride, butyl acrylate-styrene and the like. As the water-insoluble polymer compound, it is preferable to use an emulsion dispersed in water. The average particle size of the emulsion of the water-insoluble polymer compound is preferably 0.01 to 1.0 μm, particularly preferably 0.05 to 0.8 μm.

  Among the above, from the viewpoint of obtaining silver halide grains having excellent dispersion stability, the silver halide emulsion layer preferably contains a water-soluble polymer compound, and particularly preferably contains gelatin.

The silver / binder mass ratio of the silver halide emulsion layer of the conductive material precursor is preferably 1.3 or more from the viewpoint of conductivity of the conductive material obtained, and from the same viewpoint, the content of silver halide particles is silver It is preferable that it is ² g / m <2> or more in conversion. More preferably, the weight ratio of silver to binder is 1.7 to 3.5, and the content of silver halide grains is 2.5 to 4.0 g / m ² in terms of silver. If the weight ratio of silver to binder is too high, the proportion of the binder as a protective colloid of silver halide grains may be insufficient, and the dispersion stability of silver halide grains may be insufficient. In addition, when the content of silver halide grains is excessively increased, a long development time may be required, or the photosensitivity of silver halide grains closer to the support may be reduced.

  The silver halide emulsion layer may contain a developing agent. As a developing agent, a developing agent known in the field of photographic development can be used, and a developing agent which may be contained in the above-mentioned developing solution can be exemplified. Two or more developing agents may be contained.

  The silver halide emulsion layer may contain a crosslinking agent which may be contained in the physical development nucleus layer described above for the purpose of crosslinking the binder, but to remove the silver halide emulsion layer which has become unnecessary after development by washing with water, It is preferable to use a crosslinking agent in the range which does not prevent this. The silver halide emulsion layer may also contain known photographic additives. Specifically, additives described in Research Disclosure Item 17643 (December, 1978) and 18716 (November, 1979), 308119 (Dec., 1989) or described in the cited references can be exemplified. In addition, various known additives such as organic solvents, surfactants, antifoaming agents, thickeners and the like may be contained.

<Other component layers>
The conductive material precursor may optionally have a non-photosensitive layer such as a backing layer, an intermediate layer, a protective layer and the like. Among them, the conductive material precursor preferably has an intermediate layer and a protective layer. The intermediate layer is preferably provided between the physical development nucleus layer and the silver halide emulsion layer in order to accelerate the water removal of the silver halide emulsion layer which has become unnecessary after development. The protective layer protects the silver halide emulsion layer from scratching, suppresses the diffusion of silver in the silver halide emulsion layer out of the system during development, and enhances the deposition efficiency of silver on physical development nuclei. It is preferable to have it on the silver halide emulsion layer. These non-photosensitive layers are layers mainly composed of water-soluble polymer compounds, and the water-soluble polymer compounds exemplified as the binder contained in the silver halide emulsion layer can be used. The amount of the water-soluble polymer compound in the non-photosensitive layer varies depending on the use, but a range of 0.001 to 10 g / m ² is preferable. These non-photosensitive layers can contain a crosslinking agent which may be contained in the physical development nucleus layer for the purpose of crosslinking the water-soluble polymer compound, but to remove each component layer which becomes unnecessary after development by washing with water It is preferable to use in the range which does not prevent this.

In each of the above-mentioned constituent layers, it is preferable to use a non-sensitizing dye or pigment having an absorption maximum in the photosensitive wavelength range of the silver halide emulsion as a halation or anti-irradiation agent for improving the image quality. The antihalation agent is preferably used in the above-mentioned backing layer or in a layer provided between a silver halide emulsion layer such as a physical development nucleus layer or an intermediate layer and a support, and divided into two or more layers. May be As the anti-irradiation agent, it is preferable to use in the silver halide emulsion layer. The addition amount of these non-sensitizing dyes or pigments is not particularly limited as long as the intended effect can be obtained, but a range of 0.01 to 1 g / m ² is preferable. Each of the above-mentioned constituent layers can contain known photographic additives, surfactants, matting agents, lubricants, and developing agents which may be contained in a developing solution described later, if necessary.

<Method of manufacturing constituent layer>
The method for providing each constituent layer such as the above-mentioned physical development nucleus layer, silver halide emulsion layer, intermediate layer and protective layer on a support is not particularly limited, but from the viewpoint of providing each constituent layer with uniform thickness with good productivity. It is particularly preferable to provide by coating. Examples of the coating method include dip coating, slide coating, curtain coating, bar coating, air knife coating, roll coating, gravure coating, spray coating and the like, but are not limited thereto, and known coating methods can be used.

<Method of manufacturing conductive material>
The manufacturing method of the electrically-conductive material of this invention is demonstrated. The method for producing a conductive material of the present invention includes an exposure step of imagewise exposing the above-mentioned conductive material precursor, and a developing step of developing the exposed conductive material precursor with a developer.

<Exposure process>
The method for producing a conductive material according to the present invention aims to form a metallic silver fine line pattern having metallic silver fine lines of a desired geometric shape on a support, and an image is formed prior to the step of developing a conductive material precursor. Exposure step. As a method of imagewise exposure, a transmission original having a geometrical shape corresponding to a desired metallic silver fine line pattern is prepared, and the exposed original is adhered to the side of the conductive material precursor having the silver halide emulsion layer. Or exposing the surface of the conductive material precursor on which the silver halide emulsion layer is to be formed, by irradiating with various laser light (for example, laser light emitted from a blue semiconductor laser having an oscillation wavelength of 400 to 430 nm). The method etc. which scan-expose to the geometric shape according to the metal silver fine wire pattern to desire can be illustrated.

<Development process>
The method for producing a conductive material of the present invention has a developing step of developing by bringing an exposed conductive material precursor into contact with the developer described above. By bringing the exposed conductive material precursor into contact with a developer, silver halide grains in the silver halide emulsion layer are dissolved and diffused, and reduced on physical development nuclei to form a metallic silver fine line pattern. In this case, when negative-working silver halide grains are used as the conductive material precursor, the portions corresponding to the silver halide emulsion layers which were not irradiated with light become metallic silver fine lines, and positive-working silver halide grains In the case where is used, the portion corresponding to the silver halide emulsion layer irradiated with light by exposure becomes metallic silver fine lines.

<Development conditions>
The temperature of the developer to be brought into contact with the conductive material precursor is not particularly limited, but from the viewpoint of obtaining stable developability and from the viewpoint of preventing the silver halide emulsion layer from eluting into the developer, Preferably, 18 ° C to 27 ° C is particularly preferred. The development time is preferably 120 seconds or less in consideration of production efficiency.

As a method of bringing the developer into contact with the conductive material precursor after imagewise exposure, an immersion method and a coating method can be exemplified. The immersion method is, for example, to convey the exposed conductive material precursor while immersing it in the developer stored in the tank, and the application method is, for example, 1 m of the developer on the conductive material precursor. It is applied about 40 to 120 mL per ^two .

<Washing process>
After developing the conductive material precursor according to the above method, it is preferable to wash with water. By washing the conductive material precursor after development with water, each constituent layer such as a silver halide emulsion layer which has become unnecessary after development can be removed to expose the metal silver fine wire on the support. The water washing may be carried out with water alone, with water containing a pH buffer such as carbonate or phosphate, or with water containing a preservative for the purpose of preventing putrefaction.

  As a method of washing with water, there is a method of removing while spraying a warm water shower using a scrubbing roller or the like, or a method of removing hot water by the force of water while jet spraying with a nozzle or the like. In addition, a plurality of showers or slits can be provided to increase the removal efficiency. Further, when removing the silver halide emulsion layer, instead of washing with water, a method of transferring and peeling on a release paper or the like may be used. As a method of transferring and peeling off with release paper etc., excess developer on the silver halide emulsion layer is squeezed in advance with a roller etc., and the silver halide emulsion layer etc. It is a method of transferring to a release paper from a support and peeling. As the release paper, a water-absorbent paper or nonwoven fabric, or a paper provided with a water-absorbent void layer on which a particulate pigment such as silica and a binder such as polyvinyl alcohol are used.

<Post-processing after development>
A known metal surface treatment may be applied to the surface of the metallic silver fine wire obtained by developing the conductive material precursor. For example, a reducing substance as described in JP-A-2008-34366, a water-soluble phosphorus oxo acid compound, or a water-soluble halogen compound may be allowed to act, as described in JP-A-2013-196779. A triazine having two or more mercapto groups in the molecule or a derivative thereof may be allowed to act, and a blackening treatment by a sulfurization reaction may be performed as described in JP-A-2011-209626. Alternatively, as described in Japanese Patent Application Laid-Open No. 2007-12404, a treatment solution containing an enzyme such as a proteolytic enzyme may be used to promote removal of remaining gelatin and the like.

<Conductive material>
Although the line width of the metal silver fine wire on the support of the conductive material obtained by the method for producing a conductive material of the present invention is not particularly limited, it is preferable from the viewpoint of the reliability of the conductive material that it is 1 to 500 μm.

  When the conductive material obtained by the method for producing a conductive material of the present invention is used for a touch panel sensor, the conductive material preferably has a reticulated metal silver fine wire pattern made of metal silver fine wires. It is preferable that the reticulated metallic silver fine line pattern has a geometric shape in which a plurality of unit lattices are arranged in a reticulated manner from the viewpoint of the sensitivity of the sensor, visibility (low visibility), and the like. The shape of the unit cell may, for example, be a triangle such as an equilateral triangle, an isosceles triangle or a right triangle, a square, a rectangle, a rhombus, a parallelogram, a quadrangle such as a trapezoid, a hexagon, an octagon, a dodecagon, a dodecagon etc. The shape which combined the n-gon, the star shape, etc. of S is mentioned, Moreover, the single repetition of these shapes, or the combination of two or more types of several shapes is mentioned. Above all, the shape of the unit cell is preferably square or rhombus. In addition, irregular geometric shapes represented by Voronoi figures, Delaunay figures, Penrose tile figures and the like are also preferable shapes of the reticulated metallic silver fine line pattern.

  When the conductive material obtained by the method for producing a conductive material of the present invention is used for a touch panel sensor, the above-mentioned conductive material, or the surface on the other side of the conductive material on the side having metal silver fine wires, Films made of chemically tempered glass, soda glass, quartz glass, glass such as non-alkali glass, films made of various resins such as polyethylene terephthalate, and hard coat layer, antireflective layer, antiglare layer on at least one surface of the above glass or film A material having a known functional layer such as a polarizing layer, a conductive film made of ITO or the like can be provided via the adhesive layer. The adhesive layer is not particularly limited, and an optical adhesive tape using an acrylic pressure-sensitive adhesive having high transparency as exemplified in JP-A-9-251159, JP-A-2011-74308, etc. A well-known thing, such as highly curable curable resin which is illustrated by 2009-48214, Unexamined-Japanese-Patent No. 2010-257208 grade | etc. ,, can be used. Adhesive tapes for optical use and curable resins having high transparency are both commercially available, and in the former case, high transparency adhesive transfer tape (8171CL / 8172CL / 8146-1 / 8146-2 / 8146-3 manufactured by Sumitomo 3M Ltd.) / 8146-4 etc.), transparent adhesive sheet for optical use (LUCIACS (registered trademark) CS 96 22 T / CS 98 62 UA etc.) manufactured by Nitto Denko Corp., Sekisui Chemical Co., Ltd. highly transparent double-sided tape 5400X series (5405X-75 / 5407X 75 etc.), and in the latter, Dexerials Inc. product photoelastic resin SVR (registered trademark) series (SVR 1150, SVR 1320 etc.), Kyoritsu Chemical Industries Ltd. product WORLD ROCK (registered trademark) series (HRJ (registered) Trademark) -46, HRJ-203, etc.), UV curing by Henkel Japan Ltd. -Type optical transparent adhesive Loctite (registered trademark) LOCA series (Loctite 3192, 3193, 3195, 5192 etc.) can be exemplified, and any of them can be preferably used.

  Hereinafter, the present invention will be described in detail using examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded.

<Preparation of conductive material precursor>
A polyethylene terephthalate film with a thickness of 100 μm was used as a support. The total light transmittance of the support was 92%, and the haze was 0.8%.

  Next, a physical development nucleus layer coating solution of the following composition was applied onto a support and dried to provide a physical development nucleus layer.

<Preparation of palladium sulfide sol>
Liquid A: 5 g of palladium chloride
Hydrochloric acid 40mL
Distilled water 1000mL
Liquid B sodium sulfide 8.6g
Distilled water 1000mL
Solution A and solution B were mixed while stirring, and after 30 minutes, passed through a column packed with ion exchange resin to obtain palladium sulfide sol.

<Physical development nuclear layer coating solution / per ² m ² >
Said palladium sulfide sol (as solid content) 0.5 mg
2 mass% glyoxal aqueous solution 0.2 mL
Surfactant (S-1) 4 mg
Denacol (R) EX-830 25 mg
(Nagase Chemtex Co., Ltd. polyethylene glycol diglycidyl ether)
10% by weight Epomin (registered trademark) SP-200 aqueous solution 0.1 g
(Nippon Shokuhin Co., Ltd. polyethyleneimine; average molecular weight 10000)

  Subsequently, an intermediate layer, a silver halide emulsion layer, and a protective layer of the following composition were coated and dried on the physical development nucleus layer in this order from the side closer to the support, to obtain a conductive material precursor. The silver halide emulsion contained in the silver halide emulsion layer was produced by a controlled double jet method. The silver halide grains contained in this silver halide emulsion were prepared so as to have an average particle size of 0.15 μm with 95 mol% of silver chloride and 5 mol% of silver bromide. The silver halide grains thus obtained were subjected to gold-sulfur sensitization using sodium thiosulfate and chloroauric acid according to a conventional method. The silver halide emulsion thus obtained contains 0.5 g of gelatin per 1 g of silver as a protective colloid (binder).

<Intermediate layer composition / 1 m ² per>
Gelatin 0.5g
Surfactant (S-1) 5 mg
Dye 1 5 mg

<Silver halide emulsion layer composition / 1m ² per>
Silver halide emulsion 3.0 g equivalent of silver 1-phenyl-5-mercaptotetrazole 3 mg
Surfactant (S-1) 20 mg

<Per protective layer composition / 1m ^2>
1 g of gelatin
Amorphous silica matting agent (average particle size 3.5 μm) 10 mg
Surfactant (S-1) 10 mg

<Preparation of developer>
In addition to the following composition, the compounds described in Table 1 were further added to prepare developers D1 to D12.

<Developer composition>
Potassium hydroxide 25 g
Hydroquinone 18g
1-phenyl-3-pyrazolidone 2 g
Potassium sulfite 80g
15 g of N-methylethanolamine
Potassium bromide 1.2 g
Compounds described in Table 1 The addition amounts described in Table 1 were adjusted to 1000 mL, pH = 12.2 with water.

<Production of conductive material>
The conductive material precursor is in close contact with a positive-type transparent original consisting of a mesh pattern having a square with a line width of 5.0 μm and a side length of 300 μm as a unit grid, and an adhesion printer using a mercury lamp as a light source It exposed through the resin filter which cuts. Thereafter, the exposed conductive material precursor is developed with each of the developers D1 to D12 described above (immersed in a developer at 20 ° C. for 90 seconds), followed by the silver halide emulsion layer, the interlayer, and the protection. The layer was removed by washing with warm water at 40 ° C., and dried to obtain conductive materials 1 to 12 having a reticulated metallic silver fine line pattern. When the line width of the metal silver fine wire which comprises the mesh-like metal silver fine wire pattern of the conductive materials 1-12 was observed with the microscope, all were 5.0 micrometers.

<Conductive evaluation>
The surface resistivity of the reticulated metallic silver fine line pattern of the conductive materials 1 to 12 was measured according to JIS K 7194 using a Loresta (registered trademark) -GP / ESP probe manufactured by Mitsubishi Chemical Analytech Co., Ltd. Based on the surface resistivity of the reticulated metal silver fine wire pattern possessed by the conductive material 1, the surface resistivity of the reticulated metal silver fine wire pattern possessed by the conductive materials 2 to 12 is 95 to 105% of the surface resistivity of the conductive material 1 In the case of “x”, “Δ” in the case of 85% or more and less than 95%, “o” in the case of 75% or more and less than 85%, and “%” in the case of less than 75%. . The results are shown in Table 2.

  The results of Table 2 demonstrate the effectiveness of the present invention.

Claims (1)

  A conductive material characterized in that a conductive material precursor having a physical development nucleus layer and a silver halide emulsion layer at least in this order on a support is exposed and then developed with a developer containing an organic phosphonic acid chelating agent. Production method.