JP2019096445A - 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 having high conductivity, and a method for producing the conductive material.SOLUTION: A conductive material precursor has, on a support, a silver halide emulsion layer and a protective layer at least in the stated order, and the protective layer contains polyacrylic acid and/or a salt thereof. In a method for producing a conductive material, the conductive material precursor is exposed like an image and then developed.SELECTED DRAWING: None

Description

  The present invention relates to a conductive material precursor suitable for producing a conductive material that can be used for applications such as touch panels, electromagnetic wave shielding materials, antenna circuits, electronic circuits and the like, and a method for producing a 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 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 voltage applied to the light transmitting conductive layer is measured through the other light transmitting conductive layer to obtain the position where the force is applied. Detection. 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 salt photosensitive material is used as a conductive material precursor to form a light transmitting conductive layer having a mesh-like metal silver fine wire pattern formed of metal silver fine wires. 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 highly flexible and strong in bending compared to the ITO conductive film, and it is possible to form a metallic silver fine line pattern on a flexible support. Is suitable.

  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 thin the metal silver fine wires, but when the thin wires are simply made, the resistance value of the metal silver thin wires increases, and the sensitivity of the touch panel sensor is lowered. That is, there has been a demand for a conductive material precursor that can produce a conductive material having higher conductivity.

  On the other hand, JP 2007-95331 A (patent document 6) has a silver halide emulsion layer on a support as a conductive material precursor capable of producing a conductive material excellent in both transparency and conductivity. And a conductive material precursor characterized in that the sol fraction in the total hydrophilic binder in the silver halide emulsion layer is at least a constant, and as an example of the hydrophilic binder contained in the silver halide emulsion layer Polyacrylic acid is described. JP-A-2016-45459 (Patent Document 7) describes a method for producing a silver halide emulsion containing silver halide grains produced using a water-soluble polymer having a nitrogen atom content of a specific amount or less, Disclosed is a method for producing a conductive film in which a conductive portion is formed by exposing and developing a silver halide photosensitive material using the silver halide emulsion, and as an example of such a water-soluble polymer, poly (meth) acrylic acid is described. It is done. However, although the above method can provide a conductive material having good conductivity, further improvement is desired.

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 JP 2007-95331 A JP, 2016-45459, A

  An object of the present invention is to provide a conductive material precursor suitable for producing a conductive material having high conductivity, and a method for producing a conductive material from which a conductive material having high conductivity can be obtained.

The above-mentioned object of the present invention is achieved by the following invention.
(1) A conductive material precursor having a silver halide emulsion layer and a protective layer at least in this order on a support, wherein the protective layer contains polyacrylic acid and / or a salt thereof. Material precursor.
(2) A method for producing a conductive material, comprising at least an exposure step of imagewise exposing the conductive material precursor according to (1) above, and a development step of developing the exposed conductive material precursor.

  The present invention can provide a conductive material precursor suitable for producing a conductive material having high conductivity, and a method for producing a conductive material from which a conductive material having high conductivity can be obtained.

  Hereinafter, the present invention will be described. The conductive material precursor of the present invention is characterized in that the support has at least a silver halide emulsion layer and a protective layer in this order, and the protective layer contains polyacrylic acid and / or a salt thereof.

<Protective layer>
The protective layer of the conductive material precursor of the present invention is a layer provided on a silver halide emulsion layer described later, and the protective layer contains polyacrylic acid and / or a salt thereof. More specifically, polyacrylic acid in the present invention is 50 mol% or more, preferably 70 mol% or more, more preferably 90 mol% or more of acrylic acid as a monomer in 100 mol% of monomers to be subjected to polymerization of polyacrylic acid and its salt. It means a (co) polymer polymerized using at least mol%, particularly preferably 100 mol%. Examples of monomers that may be used other than acrylic acid include maleic acid and ethylene sulfonic acid. The polyacrylate in the present invention means one in which at least a part of the carboxyl group of the above-mentioned polyacrylic acid is neutralized. Examples of polyacrylates include sodium polyacrylate and ammonium polyacrylate. The weight average molecular weight of the polyacrylic acid and the salt thereof is not particularly limited, but is preferably 10000 or more because a conductive material having metal silver fine wires excellent in conductivity can be obtained, 35000 or more is more preferable, and 75000 or more Particularly preferred. The upper limit is preferably less than 1,500,000 from the viewpoint of the conductivity of the obtained conductive material and the handleability when forming the protective layer.

In the present invention, the protective layer may contain the above-described polyacrylic acid and its salt alone, or may be a combination of two or more. The content of polyacrylic acid and / or its salt in the protective layer is not particularly limited, but it is preferably ² mg / m ² or more because a conductive material having metal silver fine wires excellent in conductivity can be obtained, and 7 mg / more preferably ^{m 2} or more, particularly preferably 15 mg / ^{m 2} or more. The upper limit is not particularly limited, but is preferably 300 mg / m ² or less.

  A commercial item can be used as polyacrylic acid and its salt which were mentioned above. For example, Aquaric (registered trademark) H series, Aquaric L series, etc. commercially available from Nippon Shokubai Co., Ltd., Aron (registered trademark) series etc. commercially available from Toagosei Co., Ltd. Can be used.

  The protective layer preferably contains a binder in addition to the above-described polyacrylic acid and / or a salt thereof because the strength of the protective layer is excellent. Examples of such a binder include water-soluble polymer compounds other than the above-described polyacrylic acids and salts thereof, water-insoluble polymer compounds, and the like.

  Water-soluble polymer compounds other than polyacrylic acid and salts thereof are 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, graft polymerization polymers thereof, and the like 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, a water-soluble polymer compound is more preferable as a binder for the protective layer, and gelatin is particularly preferable because a conductive material having metal silver fine wires excellent in conductivity can be obtained. The binder content of the protective layer is not particularly limited, but is preferably 0.01 to 10 g / m ² . The content of polyacrylic acid and / or a salt thereof with respect to the binder content in the protective layer is not particularly limited, but it is 0.1 to 50% by mass to obtain a conductive material having metallic silver fine wires excellent in conductivity. And the strength of the protective layer is preferable.

  In the present invention, when the protective layer contains a water-soluble polymer compound, the protective layer can contain a crosslinking agent which may be contained in a physical development nucleus layer described later for the purpose of crosslinking the water-soluble polymer compound. In the case of forming metal silver fine lines by the silver salt diffusion transfer method, it is preferable to use them in a range that does not interfere with each component layer that becomes unnecessary after development by washing with water. In addition, the protective layer may contain various known additions such as organic solvents, surfactants, antifoaming agents, thickeners, matting agents, lubricants, and developing agents which may be contained in a developing solution described later, if necessary. Can contain an agent.

<Support>
The support of the conductive material precursor of the present invention is not particularly limited, but when the conductive material obtained by the conductive material precursor of the present invention is used for applications requiring light transmission such as touch panel sensors, the support is It is particularly preferable to have light transparency. 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 the transparency of the conductive material to be obtained, 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, 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 easily adhesive layer, a hard coat layer, an antireflective layer or an antiglare layer on at least one surface of the support.

<Silver halide emulsion layer>
The silver halide emulsion layer contained in the conductive material precursor of the present invention 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 halogen. Contains silver particles. In the production of silver halide grains, techniques used for silver halide photographic films, printing papers, films for printing plate making, emulsion masks for photomasks, etc. 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 particle diameter of the silver halide grains is 0.25 μm or less because a conductive material having metallic silver fine wires excellent in conductivity is obtained and the dispersion stability of the silver halide grains is excellent. Is preferable, and particularly preferably 0.05 to 0.2 μm. Further, silver halide grains contained in the silver halide emulsion layer are preferably 80 mol% or more of silver chloride because a conductive material having metal silver fine wires excellent in conductivity can be obtained, and particularly preferably 90 mol% or more. It is.

  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. Thereby, the negative type can be converted to a positive type, and the positive type can be converted to a negative type. 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. Specific examples thereof include the water-soluble polymer compounds that can be contained in the protective layer described above, and polyacrylic acid and salts thereof. Further, the water-insoluble polymer compound is not limited, and known compounds can be used. Specifically, the above-mentioned water-insoluble polymer compounds which can be contained in the protective layer can be exemplified.

  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.

It is preferable that the silver / binder mass ratio of the silver halide emulsion layer contained in the conductive material precursor is 1.3 or more because a conductive material having metal silver fine wires excellent in conductivity can be obtained. The content of particles is preferably ² g / m ² or more in terms of silver. More preferably, the weight ratio of silver to binder in the silver halide emulsion layer is 1.7 to 3.5, and the content of silver halide particles is 2.5 to 4.0 g / m ² in terms of silver. Is preferred. 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 a developing solution described later can be exemplified. Two or more developing agents may be contained.

  The silver halide emulsion layer can contain a crosslinking agent which may be contained in a physical development nucleus layer described later for the purpose of crosslinking the binder, but it is not necessary after development when forming metal silver fine lines by the silver salt diffusion transfer method In order to remove the silver halide emulsion layer thus obtained by washing with water, it is preferable to use a crosslinking agent in a range which does not disturb this. When forming metal silver fine lines by direct development, the silver halide emulsion layer preferably contains a crosslinking agent to impart sufficient water resistance. 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.

Physical Development Core Layer
In the method for producing a conductive material according to the present invention, forming a metal silver fine wire by silver salt diffusion transfer method does not substantially contain a binder component, and a conductive material having a metal silver fine wire excellent in conductivity is obtained. In this case, the conductive material precursor of the present invention has a physical development nucleus layer containing at least physical development nuclei on a support, and the silver halide emulsion layer described above on the physical development nucleus layer It is preferable to have a protective layer at least in this order. 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. 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. From the viewpoint of the adhesion between the metallic silver fine wire on the conductive material and the physical development nucleus layer, the content of physical development nuclei in the physical development nucleus layer is preferably 0.01 to 10 mg / m ^{2 in} solid content.

  The physical development nucleus layer preferably contains, in addition to the physical development nucleus described above, a water-soluble polymer compound exemplified as a binder which the protective layer may contain, and a water-insoluble polymer compound, and the water-soluble polymer It is more preferable to contain a compound, and 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 and adipaldehyde, and compounds having two or more epoxy groups in the molecule are preferable. The crosslinking agent is preferably contained in the physical development nucleus layer in an amount of 0.1 to 80% by mass 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-mentioned substances.

<Other component layers>
The conductive material precursor can optionally have a non-photosensitive layer such as a backing layer or an intermediate layer. In particular, in the case of forming metal silver fine lines by the silver salt diffusion transfer method, the conductive material precursor of the present invention preferably has an intermediate 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. It is also possible to provide an intermediate layer between the silver halide emulsion layer and the protective layer for the purpose of preventing inter-layer mixing of the silver halide emulsion layer and the protective layer. In any case, the protective layer is located on the side remote from the support relative to the silver halide emulsion layer, and there is no change in the order of the silver halide emulsion layer and the protective layer on the support. However, having at least the silver halide emulsion layer and the protective layer in the present invention in this order also means that the effects of the present invention can be obtained as long as the positional relationship described above is maintained.

The non-photosensitive layer described above is a layer mainly composed of a water-soluble polymer compound, and the water-soluble polymer compound 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 when forming metal silver fine lines by the silver salt diffusion transfer method, In order to wash away each component layer which became unnecessary after development by washing, it is preferable to use in the range which does not disturb 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 of the protective layer, silver halide emulsion layer, physical development nucleus layer, intermediate layer and backing layer on the support is not particularly limited, but each constituent layer of uniform thickness can be produced From the viewpoint of providing well, 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.

<Exposure process>
Next, the method for producing the conductive material of the present invention will be described. 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 pattern of metallic silver fine lines is prepared, and exposure is performed by closely contacting the side of the conductive material precursor having the silver halide emulsion layer. Method or Irradiated with various types of laser light (for example, laser light emitted from a blue semiconductor laser having an oscillation wavelength of 400 to 430 nm) on the side of the conductive material precursor having the silver halide emulsion layer, and desired metal silver The method etc. which scan-expose to the geometric shape according to a thin wire | line pattern etc. can be illustrated.

<Development process>
The method for producing a conductive material of the present invention has a developing step of developing (contacting with a developer) after the exposure step of imagewise exposing the conductive material precursor. In the present invention, when forming metal silver fine lines by the silver salt diffusion transfer method, silver halide grains contained in the silver halide emulsion layer are dissolved and diffused by development, and the metal silver fine line pattern is reduced on physical development nuclei. Is formed. 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. In the direct development method, the silver halide grains contained in the silver halide emulsion layer are reduced in situ by development to form a metallic silver fine line pattern.

<Developer>
When each constituent layer of the above-mentioned conductive material precursor contains a developing agent, the above-mentioned developing solution does not necessarily need to contain a developing agent, and the reduction of silver halide particles having latent image nuclei that can be developed Contains an alkaline agent to make it possible. 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 11 to 14.

  When each constituent layer of the above-mentioned conductive material precursor does not contain an amount of a developing agent capable of reducing silver halide particles having a latent image nucleus which becomes developable, the above-mentioned developer contains a developing agent Do. Examples of the developing agent contained in the developing solution include polyhydroxybenzenes such as hydroquinone, catechol, pyrogallol, methylhydroquinone and 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 And the like, such as 3-pyrazolidones, paramethylaminophenol, paraaminophenol, parahydroxyphenylglycine, paraphenylenediamine, ascorbic acid and the like, and two or more of these may be used in combination. The content of the developing agent in the developer is preferably 1 to 100 g / L because a conductive material having metallic silver fine wires excellent in conductivity can be obtained.

  The developer preferably further contains a preservative such as sodium sulfite or potassium sulfite, and a pH buffer such as carbonate or phosphate in order to maintain the pH within a preferred range. Further, it may contain an antifoggant such as bromide ion, benzimidazole, benzotriazole, 1-phenyl-5-mercaptotetrazole or the like added so that silver halide grains having no development nucleus are not reduced.

  When forming metal silver fine lines by the silver salt diffusion transfer method, the developer preferably contains a soluble silver complex salt forming agent in order to perform diffusion transfer development. As a soluble silver complex salt forming agent, specifically, thiosulfates such as ammonium thiosulfate and sodium thiosulfate, thiocyanates such as sodium thiocyanate and ammonium thiocyanate, sulfites such as sodium sulfite and potassium bisulfite Thioethers such as 1,10-dithia-18-crown-6, 2,2′-thiodiethanol, oxazolidones, 2-mercaptobenzoic acid and derivatives thereof, cyclic imides such as uracil, alkanolamines, diamines, Mesoionic compounds described in JP-A-9-171257, 5, 5-dialkylhydantoins, alkyl sulfones, etc., “The Theory of the photographic Process (4th edition, p 474 to 475)”, TH. 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 complex salt forming agent in the developer is preferably 0.1 to 40 g / L, more preferably 1 to 20 g / l, since a conductive material having metal silver fine wires excellent in conductivity can be obtained. L

<Development conditions>
Although the temperature of the developing solution at the time of developing the conductive material precursor is not particularly limited, it is preferably 15 ° C. to 30 ° C. in view of developing speed and in view of preventing the silver halide emulsion layer from eluting into the developing solution. 18 ° C. to 27 ° C. are particularly preferred. The development time is preferably 120 seconds or less in consideration of production efficiency.

As a method of developing the conductive material precursor after imagewise exposure, a method of immersing the conductive material precursor in a developer and a method of applying a developer on the conductive material precursor can be exemplified. When the developing solution is applied onto the conductive material precursor, the application amount of the developing solution is preferably about 40 to 120 mL / m ² .

  In the method for producing a conductive material according to the present invention, when forming a metallic silver fine wire using direct development, the conductive material precursor is developed and then brought into contact with a stop solution containing an acid such as acetic acid or citric acid to develop And a fixing step in which silver halide grains in an unexposed silver halide emulsion layer are dissolved and removed by contacting with a fixing solution containing a silver halide solvent such as thiosulfate and thiocyanate. It may be done.

<Washing process>
After developing the conductive material precursor according to the above method, or after the above-mentioned fixing step, it is preferable to wash with water. Particularly when forming metal silver fine lines by the silver salt diffusion transfer method, the conductive material precursor after development is washed with water to remove each constituent layer such as a silver halide emulsion layer which becomes unnecessary after development, and metal silver The fine lines can be exposed 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. This is a method of transferring the plastic resin film to a release paper and peeling it. 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 formed of metal silver fine wires. The mesh-like metallic silver fine line pattern preferably has a geometric shape in which a plurality of unit lattices are arranged in a mesh form from the viewpoints of the sensitivity of the sensor and the visibility (the shape of the sensor is hard to see). 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 as the former, high transparency adhesive transfer tape (8171CL / 8172CL / 8146-1 / 8146-2 / 8146- from Sumitomo 3M Co., Ltd.) 3 / 8146-4, etc., transparent adhesive sheet for optics (LUCIACS (registered trademark) CS9864UAS / CS9864UA etc.) from Nitto Denko Corp., etc., and as the latter, photoelastic resin SVR (registered trademark) from Dexerials Inc. Series (SVR1150, SVR1320, etc.), WORLD ROCK (registered trademark) series (HRJ (registered trademark)-46, HRJ-203, etc.) from Kyoritsu Chemical Industry Co., Ltd., UV curable optical transparent from Henkel Japan Ltd. Adhesive Loctite (registered trademark) LOCA series (Loctit 3192, Loctite3193 etc.) and the like can be exemplified, it is possible to obtain them use.

  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.

<Production of Conductive Material Precursor 1>
A polyethylene terephthalate film with a thickness of 100 μm was used as a support. The total light transmittance of the support was 91.9%, and the haze was 0.7%.

  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; number average molecular weight 10000)

  Subsequently, an intermediate layer 1, a silver halide emulsion layer 1 and a protective layer 1 of the following composition are 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 1 The The silver halide emulsion contained in the silver halide emulsion layer 1 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 1 composition / 1 m ² per>
Gelatin 0.5g
Surfactant (S-1) 5 mg
Dye 1 5 mg

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

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

<Production of Conductive Material Precursor 2>
A conductive material precursor 2 was obtained in the same manner as the conductive material precursor 1 except that 4 mg / m ^{2 of} sodium polyacrylate having a weight average molecular weight of 100,000 was contained in the protective layer 1.

<Production of Conductive Material Precursor 3>
A conductive material precursor 3 was obtained in the same manner as the conductive material precursor 1 except that 10 mg / m ^{2 of} sodium polyacrylate having a weight average molecular weight of 100,000 was contained in the protective layer 1.

<Production of Conductive Material Precursor 4>
A conductive material precursor 4 was obtained in the same manner as the conductive material precursor 1 except that 20 mg / m ^{2 of} sodium polyacrylate having a weight average molecular weight of 100,000 was contained in the protective layer 1.

<Production of Conductive Material Precursor 5>
A conductive material precursor 5 was obtained in the same manner as the conductive material precursor 1 except that 60 mg / m ^{2 of} sodium polyacrylate having a weight average molecular weight of 100,000 was contained in the protective layer 1.

<Production of Conductive Material Precursor 6>
A conductive material precursor 6 was obtained in the same manner as the conductive material precursor 1 except that 200 mg / m ^{2 of} sodium polyacrylate having a weight average molecular weight of 100,000 was contained in the protective layer 1.

<Production of Conductive Material Precursor 7>
A conductive material precursor 7 was obtained in the same manner as the conductive material precursor 1 except that 20 mg / m ^{2 of} sodium polyacrylate having a weight average molecular weight of 20,000 was contained in the protective layer 1.

<Production of Conductive Material Precursor 8>
A conductive material precursor 8 was obtained in the same manner as the conductive material precursor 1 except that 20 mg / m ^{2 of} sodium polyacrylate having a weight average molecular weight of 50,000 was contained in the protective layer 1.

<Production of Conductive Material Precursor 9>
A conductive material precursor 9 was obtained in the same manner as the conductive material precursor 1 except that 20 mg / m ^{2 of} sodium polyacrylate having a weight average molecular weight of 500000 was contained in the protective layer 1.

<Production of Conductive Material Precursor 10>
A conductive material precursor 10 was obtained in the same manner as the conductive material precursor 1 except that the protective layer 1 contained 20 mg / m ^{2 of} ammonium polyacrylate having a weight average molecular weight of 100,000.

<Production of Conductive Material Precursor 11>
A conductive material precursor 11 was obtained in the same manner as the conductive material precursor 1 except that 20 mg / m ² of polyacrylic acid having a weight average molecular weight of 100,000 was contained in the protective layer 1.

<Production of Conductive Material Precursor 12>
A conductive material precursor 12 was obtained in the same manner as the conductive material precursor 1 except that the silver halide emulsion layer 1 contained 20 mg / m ^{2 of} sodium polyacrylate having a weight average molecular weight of 100,000.

<Production of Conductive Material Precursor 13>
A conductive material precursor 13 was obtained in the same manner as the conductive material precursor 1 except that 20 mg / m ² of polyvinyl pyrrolidone having a weight average molecular weight of 450000 was contained in the protective layer 1.

<Production of Conductive Material Precursor 14>
A conductive material precursor 14 was obtained in the same manner as the conductive material precursor 1 except that 20 mg / m ² of polyvinyl alcohol having a weight average molecular weight of 100,000 was contained in the protective layer 1.

<Preparation of developer>
A developer having the following composition was prepared.
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
The total amount was adjusted to 1000 mL with water, pH = 12.2.

<Preparation of Conductive Materials 1 to 14>
With respect to each of the conductive material precursors 1 to 14 described above, 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 is adhered and adhered using a mercury lamp as a light source It exposed through the resin filter which cuts the light of 400 nm or less with a printer. Thereafter, each of the exposed conductive material precursors 1 to 14 is developed with the above-described developer (immersed in a developer at 20 ° C. for 90 seconds), followed by the silver halide emulsion layer, the interlayer, and the protective layer. The conductive material 1-14 which has a reticulated metal silver fine wire pattern was obtained by carrying out water washing removal with warm water of 40 ° C, and carrying out drying processing. When the line width of the metal silver fine wire which comprises the mesh-like metal silver fine wire pattern of the conductive materials 1-14 was observed with the microscope, all were 5.0 micrometers.

<Conductive evaluation>
The surface resistivity of the reticulated metallic silver fine wire pattern of the conductive materials 1 to 14 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 metallic silver fine wire pattern possessed by the conductive material 1, when the surface resistivity of the reticulated metallic silver fine wire pattern is 95% or more of the surface resistivity of the conductive material 1, “x”, 85 The conductivity was evaluated as “Δ” in the case of% or more and less than 95%, “○” 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 1.

  From the results of Table 1, the effectiveness of the present invention can be understood.

Claims (2)

  A conductive material precursor having a silver halide emulsion layer and a protective layer at least in this order on a support, wherein the protective layer comprises polyacrylic acid and / or a salt thereof. .   A method of producing a conductive material, comprising at least an exposure step of imagewise exposing the conductive material precursor according to claim 1 and a development step of developing the exposed conductive material precursor.