JP2019211553A - Conductive material precursor and method for producing conductive material - Google Patents

Abstract

To provide a conductive material precursor suitable for the production of a conductive material that prevents a resistance of a light-transmitting conductive layer from fluctuating due to sunlight irradiation, and a method for producing a conductive material.SOLUTION: A conductive material precursor has, on a support, at least a physical development nucleus layer and a silver halide emulsion layer in the stated order, the physical development nucleus layer having at least one metal element selected from copper, iron, tin, nickel, and cobalt. There is also provided a method for producing a conductive material that includes image-like exposing the conductive material precursor and thereafter developing it.SELECTED DRAWING: None

Description

  The present invention relates to a conductive material precursor suitable for manufacturing a conductive material with improved resistance variation in a light-transmitting conductive layer, and a method for manufacturing the conductive material.

  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 optical methods, ultrasonic methods, resistive film methods, surface capacitive methods, projection capacitive methods, etc., depending on the position detection method. A capacitance method is preferably used. The resistive film type touch panel sensor has a structure in which two conductive materials having a light transmissive conductive layer are used on a light transmissive support, and these conductive materials are arranged to face each other via a dot spacer. By applying force to one point of the sensor, the light-transmitting conductive layers contacted each other, and the voltage applied to the light-transmitting conductive layer was measured through the other light-transmitting conductive layer, and the force was applied. The position is detected. On the other hand, a projected capacitive touch panel sensor uses one conductive material having two light-transmitting conductive layers or two conductive materials having one light-transmitting conductive layer, such as a finger. The capacitance change between the light-transmitting conductive layers when the two are brought close to each other is detected, and the position where the finger is brought close is detected. The latter has excellent durability because it has no moving parts, and can detect multiple points at the same time. Therefore, the latter is widely used particularly in smartphones and tablet PCs.

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 formed on a light transmissive support by vacuum deposition or sputtering. Those provided by a dry process such as a method or an ion plating method are well known. In addition to the dry process, a conductive material having a light-transmitting conductive layer formed by a wet process using a network structure of conductive fine particles, carbon nanotubes, and metal fine particles such as metal nanowires has also been proposed. Yes.

  At present, the ITO conductive film is mainly used as the light transmissive conductive layer. However, since the ITO conductive film has a large refractive index and a large surface reflection of light, there is a problem that the total light transmittance is reduced, and since the flexibility is low, a crack occurs when the ITO conductive film is bent, resulting in an electric resistance value. There was a problem that increased. In addition, there are concerns about depletion of indium used and high production costs, and a conductive material having a light-transmitting conductive layer formed by the above-described wet process is being investigated as an alternative material.

  In recent years, a method has been proposed in which a silver salt photosensitive material is used as a conductive material precursor to form a light-transmitting conductive layer having a mesh-like metal silver fine line pattern formed of metal silver fine lines. For example, methods for forming a reticulated metallic silver fine wire pattern on a support using a direct development method are disclosed in International Publication No. 2001/51276 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2004-221564 (Patent Document 2). For example, Japanese Unexamined Patent Publication No. 2007-59270 (Patent Document 3) discloses a method of forming a reticulated metallic silver fine line pattern on a support using a curing development method. 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 soluble silver salt forming agent and a reducing agent are allowed to act on a precursor in an alkaline solution to form a reticulated metallic silver fine wire pattern on a support. In particular, according to the silver salt diffusion transfer method, a thin wire made of silver having 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 that it is more flexible than ITO conductive film and is strong against bending, so that a metal silver fine wire pattern can be formed on a flexible support. Are suitable.

  Also known is a conductive material laminate having a pressure-sensitive adhesive layer on a light-transmitting conductive layer having a mesh-like metallic silver fine wire pattern, and a functional material on the pressure-sensitive adhesive layer. For example, JP-A-2014-198811 The gazette (Patent Document 6) describes a malfunction in a wide temperature environment by using a pressure-sensitive adhesive layer having a low dielectric constant on the touch panel sensor and a laminate for a touch panel having a protective substrate on the pressure-sensitive adhesive layer. It is disclosed that it can suppress. In general, the pressure-sensitive adhesive layer is used for closely contacting each member such as a display device or a touch panel sensor.

  The conductive material laminate as described above is used in various places, for example, in places where sunlight is irradiated. However, when a conductive material laminate is prepared by providing a pressure-sensitive adhesive layer on a light-transmitting conductive layer having a mesh-like metallic silver fine wire pattern, the resistance value of the light-transmitting conductive layer is reduced when irradiated with sunlight. There was a problem of fluctuating, and improvement was required.

  As a method for improving the resistance value fluctuation of the light transmissive conductive layer due to the irradiation of sunlight, Japanese Patent Application Laid-Open No. 2015-58662 (Patent Document 7) discloses that the undercoat layer of the light transmissive conductive layer has an amino group. A conductive material laminate containing a compound and a pressure-sensitive adhesive layer containing a cationic polymerization type photocurable resin is disclosed, and JP-A-2015-106500 (Patent Document 8) discloses an undercoat layer of a light-transmitting conductive layer. Discloses a conductive material laminate comprising a compound containing an amino group and a pressure-sensitive adhesive layer containing a resin polymerized using an acylphosphine compound or a trihaloalkyl compound. JP-A-2016-210916 (Patent Document 9) discloses an interlayer filling material for a touch panel containing an acrylic pressure-sensitive adhesive obtained by polymerizing an acrylic monomer having a molecular skeleton having ultraviolet absorbing ability or light stability. A method of laminating on a light transmissive layer conductive layer is disclosed, and JP-A-2006-1608 (Patent Document 10) discloses a metal fiber and a resin layer containing metal additives such as metal particles and metal oxide particles. A film (conducting material laminate) having a metal is disclosed, and Japanese Unexamined Patent Application Publication No. 2006-21170 (Patent Document 11) discloses a light-transmitting conductive layer containing metal nanowires and light that transmits visible light having a specific wavelength or more. A display device (conductive material laminate) with a capacitively coupled touch panel input device including a transmissive layer is disclosed. However, further improvement has been desired with respect to fluctuations in the resistance value of the light-transmitting conductive layer accompanying the irradiation of sunlight.

  On the other hand, in Patent Document 4 described above, as the physical development nucleus contained in the physical development nucleus layer that the conductive material precursor has on the support, fine particles made of heavy metals or sulfides thereof, specifically, colloids such as gold and silver Examples thereof include metal sulfides obtained by mixing water-soluble salts such as palladium and zinc with sulfides. The physical development nuclei function as a catalyst for reducing a soluble silver complex salt obtained by dissolving silver halide with a soluble silver complex salt forming agent to form metallic silver by reducing with a reducing agent.

International Publication No. 2001/51276 Pamphlet JP 2004-221564 A JP 2007-59270 A JP 2003-77350 A Japanese Patent Laid-Open No. 2005-250169 JP 2014-198811 A Japanese Patent Laying-Open No. 2015-58662 JP-A-2015-106500 Japanese Patent Laid-Open No. 2016-210916 Japanese Patent Laid-Open No. 2006-1608 Japanese Patent Laid-Open No. 2006-21170

  The subject of this invention is providing the manufacturing method of a conductive material precursor suitable for manufacture of the conductive material with which resistance value fluctuation | variation of the transparent conductive layer was improved, and a conductive material.

The above 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 on a support, wherein the physical development nucleus layer is selected from copper, iron, tin, nickel, and cobalt. A conductive material precursor containing one or more metal elements.
(2) A method for producing a conductive material, comprising at least an exposure step of imagewise exposing the conductive material precursor according to (1) and a development step of developing the exposed conductive material precursor.

  According to the present invention, there are provided a conductive material precursor suitable for manufacturing a conductive material with improved resistance variation of a light-transmissive conductive layer, and a conductive material manufacturing method for obtaining a conductive material with improved resistance variation. be able to.

Schematic diagram of positive-type transparent original used in the example

  The present invention will be described below. The conductive material precursor of the present invention has at least a physical development nucleus layer and a silver halide emulsion layer in this order on a support, and the physical development nucleus layer is selected from copper, iron, tin, nickel, and cobalt. Contains one or more metal elements.

<Support>
The support of the conductive material precursor of the present invention is not particularly limited. However, when the conductive material obtained by the present invention is used for an application requiring light transmittance such as a touch panel sensor, the support has light transmittance. It is particularly preferred. As a light-transmitting support, polyolefin resins such as polyethylene and polypropylene, vinyl chloride resins such as polyvinyl chloride and vinyl chloride copolymers, epoxy resins, polyarylate, polysulfone, polyethersulfone, polyimide, Fluorine resin, phenoxy resin, triacetyl cellulose, polyethylene terephthalate, polyimide, polyphenylene sulfide, polyethylene naphthalate, polycarbonate, acrylic resin, cellophane, nylon, polystyrene resin, ABS resin and other various resin films, quartz glass, alkali-free glass Examples thereof include glass. From the viewpoint of transparency of the obtained 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%. Especially preferably, it 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 easy adhesion layer, a hard coat layer, an antireflection layer, an antiglare layer, an antistatic layer on at least one surface of the surface, corona treatment, plasma treatment, A known surface modification treatment such as primer treatment or saponification treatment may be applied.

<Physical development nucleus layer>
The conductive material precursor of the present invention has a physical development nucleus layer on a support. The physical development nucleus layer may be directly provided on the support, or may be provided on another layer of the support such as an easy adhesion layer. As the physical development nuclei contained in the physical development nuclei layer, fine particles (particle size is about 1 to several tens of nm) made of gold, silver, palladium, zinc or a sulfide thereof are used. From the viewpoint of adhesion between the metallic silver fine wire of the obtained conductive material and the physical development nucleus layer, the content of the physical development nucleus in the physical development nucleus layer is preferably 0.01 to 10 mg / m ² in terms of solid content.

  In the present invention, the physical development nucleus layer contains one or more metal elements selected from copper, iron, tin, nickel, and cobalt in addition to the above-described physical development nucleus. This metal element may be contained independently and may contain 2 or more types.

  The form of the metal element present in the physical development nucleus layer is not particularly limited, and metal ions, metal oxides, metal sulfides, metal hydroxides, and metal halogens such as fluoride, chloride, bromide, and iodide. Compounds, inorganic acid metal salts such as nitrates, sulfates, carbonates, hydrogen carbonates, phosphates, organic acid metal salts such as formates, acetates, propionates, stearates, oxycarboxylic acids, aminocarboxylic acids Examples include metal complexes, metal powders, metal colloids, and the like in which chelating agents such as acids, polycarboxylic acids, polyamines, polyols, polyphosphoric acids, phthalocyanines, and crown ethers are bonded to metal ions.

  Among the metal elements described above, copper and iron are preferable, and copper is particularly preferable because it is excellent in the effect of suppressing resistance value fluctuation of the light-transmitting conductive layer due to the irradiation of sunlight.

The amount of the above metal element in the physical development nucleus layer is preferably 1 mg / m ² or more, since it is possible to suppress a change in the resistance value of the light-transmitting conductive layer accompanying sunlight irradiation, and more preferably 3.5 mg / m 2. ² or more. In addition, since the obtained effect does not increase and the optical characteristics (haze, total light transmittance, etc.) may be lowered by coloring the physical development nucleus layer, the amount of the metal element is 50 mg / m ² or less. Is preferred.

  The physical development nucleus layer may contain a water-soluble polymer compound or a water-insoluble polymer compound as a binder in addition to the above-described physical development nucleus and metal element. Is preferable because it is excellent. A water-soluble high molecular compound is not limited, A well-known thing can be used. Specifically, proteins such as gelatin, casein and albumin, polysaccharides such as starch and dextrin, cellulose and derivatives thereof (for example, carboxymethylcellulose, hydroxylpropylcellulose and methylcellulose), alginic acid, carrageenan, guar gum, xanthan gum, fucoidan, chitosan, Examples include hyaluronic acid, polyethylene oxide, polyacrylic acid, polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl methyl ether, polyacrylamide, polyethyleneimine, polyallylamine, polyvinylamine, polylysine, and graft polymerization polymers thereof. A compound modified by a known method such as succinylated 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, and isoprene. Copolymers include 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, it is more preferable to contain a water-soluble polymer compound, and it is particularly preferable to contain a water-soluble polymer compound having an amino group such as polyethyleneimine or polyallylamine. The content of the water-soluble polymer compound or 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. A crosslinking agent is not specifically limited, A well-known crosslinking agent 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 active halogen such as -hydroxy-s-triazine salt and 2,4-dihydroxy-6-chloro-triazine salt, divinyl sulfone, divinyl ketone and N, N, N-triacryloylhexyl Hydrotriazine, 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 2.6.7 chapters of compounds having two or more epoxy groups in the molecule, such as diglycidyl ether, potassium aluminum sulfate (alum), and other “chemical reactions of polymers” (Shin Okawara, 1972, Kagaku Dojinsha) Examples include the crosslinking agents described in Chapters 5.2 and 9.3. Of these, dialdehydes such as glyoxal, glutaraldehyde, 3-methylglutaraldehyde, succinaldehyde, adipaldehyde and compounds having two or more epoxy groups in the molecule are preferable. The crosslinking agent preferably contains 0.1 to 80% by mass in the physical development nucleus layer based on 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 substances.

<Silver halide emulsion layer>
The silver halide emulsion layer of the conductive material precursor of the present invention contains a silver halide emulsion in which silver halide grains are uniformly dispersed (emulsified). Accordingly, the silver halide emulsion layer contains silver halide grains. For the production of the silver halide grains, techniques used in silver salt photographic films, photographic papers, printing plate-making films, emulsion masks for photomasks, etc. relating to silver halide emulsions 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 well known in the art such as forward mixing, reverse mixing and simultaneous mixing are used. Among them, it is preferable to use a so-called controlled double jet method in which a pAg in a liquid phase in which grains are formed is kept constant as one type of simultaneous mixing method, from the viewpoint of obtaining silver halide grains having a uniform particle diameter. In the present invention, from the viewpoint of the conductivity of the conductive material and the viewpoint of the dispersion stability of the silver halide grains, the preferred average grain diameter of the silver halide grains is 0.25 μm or less, particularly preferably 0.05 to 0.2 μm. is there. The silver halide grains contained in the silver halide emulsion layer are preferably 80 mol% or more from the viewpoint of the conductivity of the conductive material from which silver chloride is obtained, and particularly preferably 90 mol% or more.

  The shape of the silver halide grains is not particularly limited. For example, the shape can be various shapes such as a spherical shape, a cubic shape, a flat plate shape (hexagon flat plate shape, a triangular flat plate shape, a quadrangular flat plate shape, etc.), an octahedron shape, and a tetrahedron shape. Can be.

  In the process of formation or physical ripening, silver halide grains may contain a salt of a group VIII metal element such as a sulfite, lead salt, thallium salt, rhodium salt or complex thereof, iridium salt or complex salt thereof, or a complex salt thereof. You may coexist. Further, it can be sensitized by various chemical sensitizers, and methods commonly used in the art such as sulfur sensitization method, selenium sensitization method and noble metal sensitization method can be used alone or in combination.

  The silver halide grains can be spectrally sensitized as necessary. Further, the silver halide grains are not necessarily negative photosensitive, and may be silver halide grains having positive photosensitivity as required. The silver halide grains having positive photosensitivity can be produced by the method 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 exemplified as the binder that the physical development nucleus layer may contain. Among them, since a silver halide emulsion layer having excellent dispersion stability of silver halide grains can be obtained, 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 contained in the conductive material precursor is preferable from the viewpoint of the conductivity of the conductive material obtained, and from the same viewpoint, the content of silver halide grains is silver. It is preferably ² g / m ² or more in terms of conversion. More preferably, the silver / binder mass ratio 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 silver / binder mass ratio is too high, the ratio of the binder as a protective colloid for the silver halide grains is insufficient, so that the dispersion stability of the silver halide grains may be insufficient. If the content of the silver halide grains is excessively increased, a long development time may be required, or the photosensitivity of the silver halide grains on the side close to the support may be lowered.

  The silver halide emulsion layer may contain a developing agent. As the developing agent, a developing agent known in the field of photographic development can be used, and a developing agent that may be contained in a developer described later can be exemplified. Two or more developing agents may be contained.

  The silver halide emulsion layer can contain a cross-linking agent that may be contained in the physical development nucleus layer described above for the purpose of cross-linking the binder, but in order to wash away the silver halide emulsion layer that has become unnecessary after development, The cross-linking agent is preferably used in a range that does not hinder this. The silver halide emulsion layer may contain a known photographic additive. Specific examples include additives described in Research Disclosure Item 17643 (December 1978) and 18716 (November 1979) and 308119 (December 1989) or cited. In addition, you may contain various well-known additives, such as an organic solvent, surfactant, an antifoamer, and a thickener.

<Other constituent layers>
In the present invention, the conductive material precursor can have non-photosensitive layers such as a backing layer, an intermediate layer, and a protective layer, if necessary. Among these, 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 for the purpose of accelerating the washing and removal of the silver halide emulsion layer that is no longer necessary after development. The protective layer protects the silver halide emulsion layer from scratches, suppresses the silver halide emulsion layer from diffusing out of the system during development processing, and increases the efficiency of silver deposition on the physical development nuclei. From the above, it is preferable to have it on the silver halide emulsion layer. These non-photosensitive layers are layers mainly composed of a water-soluble polymer compound, and can contain the water-soluble polymer compound exemplified as the binder that the physical development nucleus layer may contain. The amount of the water-soluble polymer compound in the non-photosensitive layer varies depending on each application, but is preferably in the range of 0.001 to 10 g / m ² . These non-photosensitive layers can contain a crosslinking agent capable of crosslinking the water-soluble polymer compound for the purpose of crosslinking the water-soluble polymer compound, but each component layer that has become unnecessary after development is removed by washing with water. The cross-linking agent is preferably used in a range that does not hinder this.

Each of the above-described constituent layers preferably contains a non-sensitizing dye or pigment having an absorption maximum in the photosensitive wavelength region of the silver halide emulsion as a halation for preventing image quality improvement or an irradiation prevention agent. The antihalation agent is preferably used in the above-mentioned backing layer or a layer provided between the silver halide emulsion layer such as the physical development nucleus layer and the intermediate layer and the support, and is used separately in these two or more layers. May be. The irradiation inhibitor is preferably used in a silver halide emulsion layer. The addition amount of these non-sensitizing dyes or pigments is not particularly limited as long as the desired effect can be obtained, but a range of 0.01 to 1 g / m ² is preferable. Each of the constituent layers described above can contain a known photographic additive, surfactant, matting agent, lubricant, a developing agent that may be contained in a developer described later, and the like, if necessary.

<Method for producing component layer>
The method of providing the constituent layers of the physical development nucleus layer, the silver halide emulsion layer, the intermediate layer, the protective layer, and the backcoat layer on the support is not particularly limited. From the viewpoint of providing well, it is particularly preferable to provide by coating. Examples of the application 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 application methods can be used.

<Exposure process>
Next, the manufacturing method of the electrically conductive material of this invention is demonstrated. The method for producing a conductive material of the present invention aims to form a metal silver fine wire pattern having a metal silver fine wire having a desired geometric shape on a support, and an image is formed before the step of developing the conductive material precursor. A step of exposing in the same manner. As an image-wise exposure method, a transparent original having a geometric shape corresponding to a desired metal silver fine line pattern is prepared, and is exposed by being brought into close contact with the surface of the conductive material precursor having the silver halide emulsion layer. Method or various kinds of laser light (for example, laser light oscillated from a blue semiconductor laser having an oscillation wavelength of 400 to 430 nm) is irradiated on the surface having the silver halide emulsion layer of the conductive material precursor, and the desired metallic silver A method of scanning exposure to a geometric shape corresponding to the fine line pattern can be exemplified.

<Development process>
The method for producing a conductive material of the present invention includes a developing step of developing (contacting with a developer) the conductive material precursor after the exposure step of imagewise exposing the conductive material precursor. By development, the silver halide grains contained in the silver halide emulsion layer are dissolved and diffused, and reduced on the physical development nuclei to form a metal silver fine line pattern. In this case, when negative type silver halide grains are used as the conductive material precursor, the portion corresponding to the silver halide emulsion layer not irradiated with light by exposure becomes a metal silver fine wire, and positive type silver halide grains Is used, the portion corresponding to the silver halide emulsion layer irradiated with light by exposure becomes a fine metal silver wire.

<Developer>
When each constituent layer of the conductive material precursor described above contains a developing agent, the developer does not necessarily need to contain a developing agent, and silver halide grains having latent image nuclei that can be developed can be reduced. Contains an alkaline agent. Examples of the alkaline agent include potassium hydroxide, sodium hydroxide, lithium hydroxide, tribasic sodium phosphate, and various amine compounds. The pH of the developer is preferably 10 or more, and more preferably in the range of 11-14.

  When each of the constituent layers of the conductive material precursor described above does not contain an amount of developing agent that enables the reduction of silver halide grains having latent image nuclei that can be developed, the developer described above contains the developing agent. To do. As the developing agent contained in the developer, for example, polyhydroxybenzenes such as hydroquinone, catechol, pyrogallol, methylhydroquinone, chlorohydroquinone, 1-phenyl-4,4-dimethyl-3-pyrazolidone, 1-phenyl-3- Pyrazolidone, 1-p-tolyl-3-pyrazolidone, 1-phenyl-4-methyl-3-pyrazolidone, 1-phenyl-4-methyl-4-hydroxymethyl-3-pyrazolidone, 1-p-chlorophenyl-3-pyrazolidone Such as 3-pyrazolidones, paramethylaminophenol, paraaminophenol, parahydroxyphenylglycine, paraphenylenediamine, ascorbic acid and the like, and two or more of these may be used in combination. Since the electroconductive material which has the metal silver fine wire excellent in electroconductivity is obtained, it is preferable that content of the developing agent in a developing solution is 1-100 g / L.

  In addition, the developer preferably contains a preservative such as sodium sulfite or potassium sulfite and a pH buffer such as carbonate or phosphate in order to keep the pH within a preferable range. Furthermore, even if it contains an antifoggant added such that bromide ions, benzimidazole, benzotriazole, 1-phenyl-5-mercaptotetrazole, etc., silver halide grains having no developable latent image nucleus are not reduced. Good.

  It is particularly preferable that the developer contains a soluble silver complex salt forming agent. Specific examples of the soluble silver complex forming agent include thiosulfates such as ammonium thiosulfate and sodium thiosulfate, thiocyanates such as sodium thiocyanate and ammonium thiocyanate, and sulfites such as sodium sulfite and potassium hydrogen sulfite. Thioethers such as 1,10-dithia-18-crown-6,2,2'-thiodiethanol, oxazolidones, 2-mercaptobenzoic acid and its derivatives, cyclic imides such as uracil, alkanolamines, diamines, The mesoionic compounds described in JP-A-9-171257, 5,5-dialkylhydantoins, alkylsulfones, and other “The Theory of the Photographic Process (4th edition, p474-475)”, TH. Examples include compounds described in James. Of these soluble silver complex salt forming agents, alkanolamines are particularly preferred. Examples of the alkanolamine include N- (2-aminoethyl) ethanolamine, diethanolamine, N-methylethanolamine, triethanolamine, N-ethyldiethanolamine, diisopropanolamine, ethanolamine, 4-aminobutanol, N, N- Examples include dimethylethanolamine, 3-aminopropanol, and 2-amino-2-methyl-1-propanol. These soluble silver complex salt forming agents can be used alone or in combination. Since the electroconductive material which has the metal silver fine wire excellent in electroconductivity is obtained, as content of the soluble silver complex salt formation agent amount in a developing solution, 0.1-40 g / L is preferable, More preferably, 1-20 g / L L.

<Development conditions>
The temperature of the developer at the time of developing the conductive material precursor is not particularly limited, but is preferably 15 to 30 ° C. from the viewpoint of development speed and from the viewpoint of preventing the silver halide emulsion layer from being eluted in the developer, 18-27 degreeC is especially preferable. The development time is preferably 120 seconds or less in consideration of production efficiency.

Examples of the method of developing the conductive material precursor after imagewise exposure include a method of immersing the conductive material precursor in a developer and a method of applying a developer on the conductive material precursor. When the developer is applied on the conductive material precursor, the amount of the developer applied is preferably about 40 to 120 mL / m ² .

<Washing process>
The conductive material precursor is preferably developed according to the above method and then washed with water. By washing the conductive material precursor after development with water, each constituent layer such as a silver halide emulsion layer which becomes unnecessary after development can be removed, and the metal silver fine wire can be exposed on the support. Washing with water 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 spoilage.

  As a water washing method, there are a method of removing hot water shower while spraying using a scrubbing roller or the like, and a method of removing hot water by jetting with a nozzle or the like with the force of water. Also, a plurality of showers and slits can be provided to increase the removal efficiency. Further, when removing the silver halide emulsion layer, a method of transferring and peeling to a release paper or the like may be used instead of washing with water. As a method of transferring and peeling with release paper, etc., excess developer on the silver halide emulsion layer is squeezed out beforehand with a roller, etc., and the silver halide emulsion layer and the release paper are brought into close contact with each other to remove the silver halide emulsion layer etc. This is a method of transferring from a plastic resin film to release paper and peeling. As the release paper, water-absorbing paper or non-woven fabric, or paper having a water-absorbing void layer formed of fine pigment such as silica and binder such as polyvinyl alcohol on the paper is used.

<Post-processing after development>
A known metal surface treatment may be applied to the surface of the metal silver fine wire obtained by developing the conductive material precursor. For example, a reducing substance, a water-soluble phosphorus oxo acid compound, or a water-soluble halogen compound as described in JP 2008-34366 A may be allowed to act, as described in JP 2013-19679 A A triazine having two or more mercapto groups in the molecule or a derivative thereof may be allowed to act, and as described in JP 2011-209626 A, blackening treatment by a sulfurization reaction may be performed. Alternatively, as described in JP-A-2007-12404, treatment with a treatment solution containing an enzyme such as a proteolytic enzyme may be performed to promote the removal of remaining gelatin or the like.

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

  When the conductive material obtained by the method for producing a conductive material of the present invention is used for a touch panel sensor, it preferably has a light-transmitting conductive layer having a mesh-like metallic silver fine wire pattern, and the light-transmitting conductive layers are electrically connected to each other. It is preferable to have a sensor unit having a plurality of sensors that are electrically insulated. The mesh-like metallic silver thin wire pattern preferably has a geometric shape in which a plurality of unit cells are arranged in a mesh shape from the viewpoint of sensor sensitivity and visibility (so-called difficult visibility that the sensor shape is difficult to see). Examples of unit cell shapes include triangles such as regular triangles, isosceles triangles, right triangles, squares, rectangles, rhombuses, parallelograms, trapezoids, etc., hexagons, octagons, dodecagons, decagons, etc. The shape which combined n square, star shape, etc. of these is mentioned, The repetition of these shapes independently, or the combination of two or more types of multiple shapes is mentioned. Among them, the shape of the unit cell is preferably a square or a rhombus. Irregular geometric shapes represented by Voronoi figures, Delaunay figures, Penrose tile figures, etc. are also one of the preferred mesh-like metallic silver thin line patterns.

  From the viewpoint of visibility (difficult visibility), the line width of the metal silver fine wires constituting the mesh-like metal silver fine wire pattern is preferably 20 μm or less, and more preferably 1 to 10 μm. Moreover, it is preferable from a viewpoint of the sensitivity of a sensor, and visibility (difficult visibility) that the repeating space | interval of a unit cell is 50-600 micrometers, More preferably, it is 50-400 micrometers. The aperture ratio of the mesh-like metallic silver fine wire pattern is preferably 85% or more from the viewpoint that the conductive material is excellent in transparency, and more preferably 88 to 99%.

  The conductive material obtained by the method for producing a conductive material of the present invention is suitable for a conductive material laminate having an adhesive layer on a light transmissive conductive layer, and further a conductive material laminate having a functional material on the adhesive layer. Suitable for the body. Examples of the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer include known pressure-sensitive adhesives such as a rubber-based pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, and a urethane-based pressure-sensitive adhesive. The functional material includes a conductive material having a light-transmissive conductive layer on a support, a protective plate made of glass or a resin film, and a hard coat layer, an antireflection layer, an anti-reflection layer on at least one surface of the glass or resin film. Examples thereof include materials having a known functional layer such as a glare layer, a conductive non-metallic layer made of ITO or the like, a light shielding layer, a decorative layer, and the like.

  As the pressure-sensitive adhesive layer, an optical pressure-sensitive adhesive tape using a highly transparent acrylic pressure-sensitive adhesive exemplified in JP-A-9-251159, JP-A-2011-74308 and the like, and JP-A-2009-48214 Moreover, you may use the hardened | cured material of highly transparent curable resin illustrated by Unexamined-Japanese-Patent No. 2010-257208 etc. Both optical adhesive tapes and highly transparent curable resins are commercially available, and the former is a highly transparent adhesive transfer tape (8146-1 / 8146-2 / 8146-3 / 8146-) from 3M Japan. 4), an optical transparent adhesive sheet (LUCIACS (registered trademark) CS9864UAS / CS9864UA, etc.) and the like can be exemplified from Nitto Denko Corporation, and the latter includes an optical elastic resin SVR (registered trademark) series (SVR1150) from Dexialials Corporation. , SVR1320, etc.), WORLD ROCK (registered trademark) series (HRJ (registered trademark) -46, HRJ-203, etc.) from Kyoritsu Chemical Industry Co., Ltd., UV curable optical transparent adhesive Loctite (from Henkel Japan Co., Ltd.) Registered Trademark) LOCA Series (Loctite 3192, Locit 3193, etc.) and the like can be exemplified, it is possible to obtain them use.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example, this invention is not limited to a following example, unless the summary is exceeded.

<Preparation of Conductive Material Precursor 1>
A polyethylene terephthalate film having a thickness of 100 μm was used as the support. When the total light transmittance and haze of the support were measured with a haze meter HZ-V3 manufactured by Suga Test Instruments Co., Ltd., the total light transmittance was 91.8%, and the haze was 0.6%.

  Next, a physical development nucleus layer coating solution 1 having the following composition was applied onto a support and dried to provide a physical development nucleus layer containing palladium sulfide as a physical development nucleus.

<Preparation of palladium sulfide sol>
Liquid A Palladium chloride 5g
Hydrochloric acid 40mL
Distilled water 1000mL
B liquid sodium sulfide 8.6g
Distilled water 1000mL
Liquid A and liquid B were mixed with stirring, and 30 minutes later, the solution was passed through a column filled with an ion exchange resin to obtain palladium sulfide sol.

<Per physical development core layer coating solution 1/1 m ² >
The palladium sulfide sol (as solid content) 0.5mg
2% by mass aqueous glyoxal solution 0.2mL
Surfactant (S-1) 4mg
Denacol (registered trademark) EX-830 25mg
(Polyethylene glycol diglycidyl ether manufactured by Nagase ChemteX Corporation)
10% by mass of Epomin (registered trademark) SP-200 aqueous solution 0.1 g
(Nippon Shokubai Polyethyleneimine; number average molecular weight 10,000)

  Subsequently, an intermediate layer, a silver halide emulsion layer, and a protective layer having the following composition were coated on the physical development nucleus layer in order from the side closer to the support and dried to obtain a conductive material precursor 1. 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 that the average particle diameter was 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 as a protective colloid (binder) per 1 g of silver.

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

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

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

<Preparation of Conductive Material Precursors 2-12>
In the production of the conductive material precursor 1, the physical development nucleus layer coating solution 1 contains the inorganic acid metal salt, the organic acid metal salt, and the metal halide shown in Table 1 with the metal element contents shown in Table 1. Thus, conductive material precursors 2 to 12 were obtained in the same manner except that each was added.

<Preparation of conductive materials 1-12>
The conductive material precursors 1 to 12 and the positive-type transparent original shown in FIG. 1 were brought into close contact with each other and exposed through a resin filter that cut light of 400 nm or less with a contact printer using a mercury lamp as a light source. The positive-type transparent original has a test pattern equivalent portion 13 (5 lines 13a to 13e) composed of a mesh-like metallic silver fine line pattern equivalent portion 11 and filled silver pattern equivalent portions 12 and 12 ′. The filled silver pattern equivalent portions 12 and 12 'constituting the test pattern equivalent portion 13 are mesh-like metallic silver fine wires formed by rhomboid unit cells having a line width of 5.0 μm, a side length of 300 μm, and a narrow angle of 60 ° They are connected via the pattern equivalent part 11. In the drawing, the broken line represents a functional material bonding region 20 described later, and there is no broken line on the positive-type transparent original.

  Thereafter, the film was immersed in the following diffusion transfer developer at 20 ° C. for 60 seconds, and then the silver halide emulsion layer, intermediate layer, and protective layer were washed away with warm water at 40 ° C. and dried. In this way, conductive materials 1 to 12 having a light-transmitting conductive layer having a mesh-like metallic silver fine wire pattern and five test patterns (five of 13a to 13e in a positive transmission original) made of a solid silver pattern are obtained. It was. When the obtained conductive materials 1 to 12 were observed with a digital microscope, the shape of the pattern and the line width were the same as those of the above-described positive-type transparent original.

<Diffusion transfer developer composition>
Potassium hydroxide 25g
Hydroquinone 18g
1-phenyl-3-pyrazolidone 2g
Potassium sulfite 80g
N-methylethanolamine 15g
Potassium bromide 1.2g
The total amount was adjusted to 1000 mL with water and pH = 12.2.

<Evaluation of change rate of resistance value of conductive material>
About each of the electrically conductive materials 1-12, 3M Japan Co., Ltd. highly transparent adhesive transfer tape 8146-4 was bonded to the bonding area | region 20 of the functional material, and it was set as the 100-micrometer-thick adhesive layer. Subsequently, EAGLE XG (registered trademark) (non-alkali glass manufactured by Corning Japan Co., Ltd.) was bonded as a functional material on the pressure-sensitive adhesive layer to prepare a laminate. In addition, a silver paste (DW-260H-1 manufactured by Toyobo Co., Ltd.) was applied to a portion exposed from the laminated body of the painted silver pattern of the five test patterns, and dried to form a silver paste coating portion. The value can be easily measured.

The resistance value between the silver paste coating portions of the five test patterns of each laminate at both ends was measured using a digital multimeter PC700 manufactured by Sanwa Electric Meter Co., Ltd., and the initial resistance value Ra of each of the five test patterns was measured. -Re (unit: kΩ) was obtained. Next, the laminate was irradiated with xenon lamp light (light having a spectral distribution similar to sunlight) for 1000 hours using a xenon weather meter NX25 manufactured by Suga Test Instruments Co., Ltd. The conditions were set to irradiance 60 W / m ² (wavelength 300 nm to 400 nm), tank temperature 38 ° C., tank humidity 50% RH, and black panel temperature 63 ° C. in accordance with JIS K7350-2. After the completion of irradiation, the resistance value was measured again for each of the five test patterns of the laminate, and resistance values R′a to R′e (unit: kΩ) were obtained. And according to the following formula | equation, the resistance value change rate (unit:%) before and behind xenon lamp light irradiation is calculated about each of five test patterns, Furthermore, resistance value change rate of five test patterns is averaged, and the conductive material 1 It was set as the average resistance value change rate (unit:%) of -12. The results are shown in Table 1.
Change rate of resistance value of test pattern x (unit:%) = {(R′x−Rx) / Rx} × 100
In the formula, x represents a to e.

  The effectiveness of the present invention can be seen from the results in Table 1.

11 Mesh-like metallic silver fine wire pattern equivalent part 12, 12 'Filled silver pattern equivalent part 13a-13e Test pattern equivalent part 20 Bonding area of functional material

Claims (2)

  A conductive material precursor having at least a physical development nucleus layer and a silver halide emulsion layer in this order on a support, wherein the physical development nucleus layer is one or more selected from copper, iron, tin, nickel and cobalt A conductive material precursor containing a metal element.   A method for producing a conductive material comprising at least an exposure step of imagewise exposing the conductive material precursor according to claim 1 and a developing step of developing the exposed conductive material precursor.