JP2009245748A - Method of manufacturing conductive material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a conductive material for stably manufacturing a uniform conductive material with high surface resistivity. <P>SOLUTION: In the method of manufacturing the conductive material for manufacturing a conductive material by the imagewise exposure of a conductive material precursor having at least a physical development core layer and a silver halide emulsion layer in that order on a support and precipitating metal silver on the physical development core layer by a diffusion transfer method, a whole face of the conductive material precursor is given a sub exposure before and/or after it is exposed in image. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a conductive material that can be used in applications such as an electric circuit, an antenna circuit, an electromagnetic shielding material, and a touch panel.

  In recent years, electronic devices such as printed circuit boards have been required to have higher density and higher definition as electronic devices are strongly required to be downsized.

  Examples of methods for manufacturing electrical circuits include: 1) applying an insulating substrate coated with a conductive material such as copper, gold, ITO, tin oxide, 2) applying a photoresist agent such as a photosensitive resin, 3) desired 4) Curing the photoresist agent by applying UV mask etc. 5) After removing the uncured part, 6) Remove the unnecessary copper foil part by chemical etching etc. A forming method (subtractive method) is known. In this method, the process is complicated, and it is difficult to draw a high-definition image line because it has a metal etching process.

  As a method of drawing a high-definition image line, 1) electroless plating catalyst is applied to an insulating substrate, 2) a photoresist agent is applied, exposed and developed, and 3) electroless plating is performed to form a conductive pattern. 4) A method of removing the plating resist (full additive method), or 1) An electroless plating catalyst is applied to the insulating substrate, electroless plating is applied, and 2) a photoresist agent is applied, exposed and developed. 3) A method (semi-additive method) in which electrolytic plating is performed to form a conductive pattern and 4) a plating resist or the like is peeled is also known. However, these methods have complicated steps, and the subtractive method also has a problem that all of the used photoresist agent must be finally discarded.

  As a method of manufacturing an electric circuit by a simple process, a method of forming an electric circuit by printing a metal paste on a substrate by a screen printing method, an ink jet printing method, or the like and sintering it is known. However, it has been difficult to draw high-definition lines of 50 μm or less by screen printing or ink jet printing. Furthermore, in the case of screen printing, when a high-definition image line is to be drawn continuously, a high-definition wrinkle must be used. However, there is a problem that the wrinkle is easily clogged. In the case of the inkjet method, there is a problem that the inkjet nozzle is always clogged not only when an electric circuit is manufactured, but also when an ink composition containing a solid content is printed, including a consumer inkjet printer. . Therefore, when an electric circuit is manufactured using a printing method, there is a problem in its stability.

  In recent years, a method using a silver salt photographic light-sensitive material having a silver halide emulsion layer as a conductive material precursor has been proposed from the viewpoint of easily and stably producing a uniform and high-definition pattern. For example, in International Publication No. 01/51276 pamphlet and JP-A-2004-221564, a silver halide photographic photosensitive material is subjected to 1) image exposure and development treatment, and then 2) metal plating treatment to produce a conductive material. A method has been proposed. Similarly, a method using a silver salt diffusion transfer method has been proposed as a method using a silver salt photosensitive material, for example, Japanese Patent Application Laid-Open No. 2003-77350 (Patent Document 1). Since the conductive materials obtained by these methods use silver salt photography, it is easy to draw high-definition lines, high stability, simple processes, and very good characteristics. Show.

  On the other hand, in the application of conductive materials, various performances are required depending on the purpose, and it is necessary to control transparency, conductivity and the like to desired values. For example, a resistive film type transparent touch panel requires a surface resistivity of about 400 to 600 Ω / □ as a conductive material, and a relatively higher surface resistivity is required than an electromagnetic shielding material used for a plasma display or the like. At the same time, the uniformity of the surface resistivity within the material is also regarded as important. For example, the difference between the maximum and the minimum is required to be within 100Ω / □. An ITO film is usually used as a transparent electrode in a resistive transparent touch panel, but ITO faces a problem of resource depletion, and an alternative is demanded.

  In the method disclosed in JP-A-2003-77350, when producing a transparent conductive material suitable for resistive film type transparent touch panel application, as a method for controlling the surface resistivity high, in the mesh pattern metal silver obtained There is a method for adjusting the interval between mesh patterns. If the interval between the mesh patterns is increased, the surface resistivity increases, but if it is excessively performed, the presence of the mesh pattern can be recognized, which is not preferable. For this reason, the adjustment range of the surface resistivity is limited and is not very useful.

Next, as a method of increasing the surface resistivity, there is a method of reducing the line width of the mesh pattern. For example, when performing scanning exposure with a laser light source, there are methods of adjusting the number of scans and adjusting the laser output, and for contact exposure, there are methods of adjusting the line width of the mask and adjusting the exposure time. If the line width is narrowed at intervals of mesh patterns that are difficult to see, the surface resistivity increases. However, since the surface resistivity changes relatively rapidly, a large difference occurs in the surface resistivity even with a slight exposure amount. For this reason, the surface resistivity of the obtained conductive material often has non-uniformity in the material, and it has been difficult to stably produce a conductive material having a uniform surface resistivity. For this reason, the manufacturing method of the electroconductive material which has a high surface resistivity and can manufacture a uniform electroconductive material stably was calculated | required.
Japanese Patent Laying-Open No. 2003-77350 (first page)

  Accordingly, an object of the present invention is to provide a method for producing a conductive material, which can stably produce a uniform conductive material having a high surface resistivity.

  A conductive material precursor having at least a physical development nucleus layer and a silver halide emulsion layer in this order on the support is imagewise exposed, and metallic silver is deposited on the physical development nucleus layer by a diffusion transfer method to make the conductive material conductive. In the manufacturing method of the electroconductive material which manufactures material, subexposure is given to the whole surface of an electroconductive material precursor before and / or after image-wise exposure, The manufacturing method of the electroconductive material characterized by the above-mentioned.

  According to the present invention, it is possible to provide a method for manufacturing a conductive material that stably manufactures a uniform conductive material having a high surface resistivity.

  The conductive material precursor used in the present invention has at least a physical development nucleus layer and a silver halide emulsion layer on the support in this order from the side closer to the support. Further, the non-light-sensitive layer is used as an outermost layer farthest from the support and / or an intermediate layer between the physical development nucleus layer and the silver halide emulsion layer, or an undercoat layer between the support and the physical development nucleus layer. You may have.

  Examples of the support for the conductive material precursor used in the present invention include polyester resins such as polyethylene terephthalate, diacetate resins, triacetate resins, acrylic resins, polycarbonate resins, polyvinyl chloride, polyimide resins, cellophane, and celluloid. Film, etc. Among them, a light transmissive support having a total light transmittance of 80% or more is desirable for the resistive film type transparent touch panel.

As the physical development nuclei contained in the physical development nucleus layer of the conductive material precursor used in the present invention, fine particles (having a particle size of about 1 to several tens of nm) made of heavy metal or a sulfide thereof are used. Examples thereof include colloids such as gold and silver, metal sulfides obtained by mixing water-soluble salts such as palladium and zinc and sulfides, and the like. The fine particle layer of these physical development nuclei can be provided on the support on which the undercoat layer is formed by a coating method or an immersion treatment method. From the viewpoint of production efficiency, a coating method is preferably used. The content of physical development nuclei in the physical development nuclei layer is suitably about 0.1 to 10 mg per m ^{2 in} terms of solid content.

  The physical development nucleus layer used for the conductive material precursor may contain a water-soluble polymer. When the water-soluble polymer is used, the addition amount is preferably about 0 to 500% by mass with respect to the physical development nucleus. As the water-soluble polymer, gum arabic, cellulose, sodium alginate, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamide, a copolymer of acrylamide and vinyl imidazole, and the like can be used.

  The physical development nucleus layer of the conductive material precursor can also contain a crosslinking agent. Examples of the crosslinking agent include inorganic compounds such as chromium alum, aldehydes such as formaldehyde, glyoxal, malealdehyde, and glutaraldehyde, N-methylol compounds such as urea and ethyleneurea, mucochloric acid, and 2,3-dihydroxy. Aldehyde equivalents such as -1,4-dioxane, compounds having active halogen such as 2,4-dichloro-6-hydroxy-s-triazine salt and 2,4-dihydroxy-6-chloro-triazine salt, Divinyl sulfone, divinyl ketone, N, N, N-triacryloyl hexahydrotriazine, compounds having two or more active three-membered ethyleneimino groups and epoxy groups in the molecule, and dimers as polymer hardeners One or more of various compounds such as aldehyde starch can be used. Among the crosslinking agents, dialdehydes such as glyoxal, glutaraldehyde, 3-methylglutaraldehyde, succinaldehyde, and adipaldehyde are preferable, and glutaraldehyde is more preferable. The crosslinking agent is preferably contained in the physical development nucleus layer in an amount of 0.1 to 30% by mass, particularly preferably 1 to 20% by mass, based on the water-soluble polymer contained in the physical development nucleus layer.

  The physical development nucleus layer can be applied by an application method such as dip coating, slide coating, curtain coating, bar coating, air knife coating, roll coating, gravure coating, spray coating and the like.

  In the conductive material precursor used in the present invention, a silver halide emulsion layer is provided as an optical sensor. Techniques used in silver halide photographic films, photographic papers, printing plate-making films, emulsion masks for photomasks, etc. relating to silver halide can be used as they are. The silver halide emulsion capable of obtaining the above-described excellent effects by the subexposure of the present invention is a negative type silver halide emulsion.

  The formation of silver halide emulsion grains used in the silver halide emulsion layer is performed by Research Disclosure Item 17643 (December 1978) and 18716 (November 1979), 308119 (forward mixing, reverse mixing, simultaneous mixing, etc.). (December 1989) can be used. Among them, it is preferable to use a so-called controlled double jet method, which is one of the simultaneous mixing methods and keeps the pAg in the liquid phase to be formed constant, from the viewpoint of obtaining silver halide emulsion grains having a uniform particle size. . In the conductive material precursor of the present invention, the preferred silver halide emulsion grains have an average grain size of 0.25 μm or less, particularly preferably 0.05 to 0.2 μm. There is a preferred range for the halide composition of the silver halide emulsion used in the present invention, and it is preferable to contain 80 mol% or more of chloride, particularly preferably 90 mol% or more of chloride.

  In the production of silver halide emulsions, group VIII such as sulfite, lead salt, thallium salt, rhodium salt or complex thereof, iridium salt or complex thereof, in the process of forming silver halide grains or physical ripening as necessary A metal element salt or a complex salt thereof 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. In the conductive material precursor used in the present invention, the silver halide emulsion can be dye-sensitized as necessary.

The ratio of the amount of silver halide and the amount of gelatin contained in the silver halide emulsion layer is such that the mass ratio of silver halide (silver equivalent) to gelatin (silver / gelatin) is 1.2 or more, more preferably 1. 5 or more. The amount of silver halide contained in the silver halide emulsion layer is preferably ² to 10 g / m ² in terms of silver.

  In the silver halide emulsion layer, known photographic additives can be used for various purposes. These are described in Research Disclosure Item 17643 (December 1978) and 18716 (November 1979), 308119 (December 1989) or cited.

  In the conductive material precursor used in the present invention, a non-photosensitive layer can be provided between the silver halide emulsion layer and the physical development nucleus layer or on the silver halide emulsion layer. These non-photosensitive layers are layers having a water-soluble polymer as a main binder. As the water-soluble polymer mentioned here, any polymer can be selected as long as it easily swells with a developing solution and allows the developing solution to easily penetrate into the underlying silver halide emulsion layer and physical development nucleus layer.

  Specifically, gelatin, albumin, casein, polyvinyl alcohol, or the like can be used. Particularly preferred water-soluble polymers are proteins such as gelatin, albumin and casein. In order to sufficiently obtain the effects of the present invention, the amount of the binder in the non-photosensitive layer is preferably in the range of 20 to 100% by mass, particularly 30 to 80% by mass, based on the total amount of binder in the silver halide emulsion layer. % Is preferred.

  These non-photosensitive layers may be added to known photographic additives as described in Research Disclosure Item 17643 (December 1978) and 18716 (November 1979), 308119 (December 1989), if necessary. An agent can be included. Further, the film can be hardened with a crosslinking agent as long as the peeling of the silver halide emulsion layer after the treatment is not prevented.

For the conductive material precursor used in the present invention, it is preferable to use a non-sensitizing dye or pigment having an absorption maximum in the photosensitive wavelength region of the silver halide emulsion layer as a halation for improving image quality, or an irradiation prevention agent. . The antihalation agent is preferably provided with the above-described undercoat layer or physical development nucleus layer, or an intermediate layer provided as necessary between the physical development nucleus layer and the silver halide emulsion layer, or a support. It can be contained in the backing layer. The irradiation inhibitor is preferably contained in the silver halide emulsion layer. The amount added may vary widely as long as the desired effect can be obtained. For example, when it is contained in the backing layer as an antihalation agent, it is preferably in the range of about 20 mg to about 1 g per m ² , preferably The absorbance at the maximum absorption wavelength is 0.5 or more.

  A method for producing a conductive material using the conductive material precursor will be described. Examples of the conductive material include a silver thin film having a mesh pattern. After exposure to an image (for example, a mesh pattern), it is processed with a diffusion transfer developer, and then unnecessary layers on the physical development nucleus layer are removed by washing or the like to form a silver film having a mesh pattern. The production method of the present invention is characterized in that sub-exposure is performed before and / or after the conductive material precursor is exposed to a network pattern.

  The exposure of the conductive material precursor in the present invention will be described. The silver halide emulsion layer of the conductive material precursor is exposed imagewise, but as an exposure method, a method of exposing the transmission pattern of the mesh pattern and the silver halide emulsion layer in close contact with each other, or using various laser beams Scanning exposure method. In the above-described method of exposing with laser light, for example, a blue semiconductor laser (also referred to as a violet laser diode) having an oscillation wavelength of 400 to 430 nm can be used.

  Next, sub-exposure will be described. The sub-exposure provides uniform and relatively weak exposure on the entire surface of the conductive material precursor, and can be performed before and / or after the exposure of the mesh pattern. By sub-exposure, the amount of metallic silver of the conductive material obtained by processing of the silver salt diffusion transfer developer can be made smaller than the amount of metallic silver obtained only by network pattern exposure. By adjusting the amount of sub-exposure, the amount of metallic silver in the mesh pattern can be arbitrarily changed, and the surface resistivity of the conductive material can be controlled. The sub-exposure is not particularly limited as long as it is a light source having an emission spectrum in the photosensitive wavelength region of the conductive material precursor, and can be performed with a fluorescent lamp, various lamps, various laser lights, and the like. It is important that the sub-exposure be performed uniformly over the entire surface of the conductive material precursor. If non-uniform, the conductive material also has non-uniform surface resistivity. The subexposure can be performed by adjusting the amount of light using an exposure apparatus that performs pattern exposure, but a contact printer that can be uniformly performed in a short time is preferable.

  The amount of sub-exposure varies depending on the sensitivity of the conductive material precursor, but is preferably 5 to 15% of the appropriate exposure amount for imagewise exposure. Here, the appropriate exposure amount is, for example, a light amount in which the line width after the development processing is equal to the line width of the original if the transmission original and the silver halide emulsion layer are in close contact with each other. Then, the amount of light at which the line width after development processing becomes equal to the specified line width.

  As described above, the purpose of the sub-exposure is to reduce the amount of metallic silver in the mesh pattern and to make the surface resistivity uniform over the entire surface. As a method of reducing the amount of metallic silver in the network pattern, for example, there is a method of reducing the amount of the silver halide emulsion of the conductive material precursor. However, a conductive material in which the amount of silver halide emulsion is reduced to increase the surface resistivity is not a desirable method because the surface resistivity varies greatly from place to place and is not uniform.

  The development processing with the silver salt diffusion transfer developer of the conductive material precursor in the present invention will be described. The conductive material precursor silver halide emulsion layer subexposed before and / or after imagewise exposure as described above is subjected to physical development by being processed with a silver salt diffusion transfer developer and developable. A silver halide having no latent image nuclei is dissolved by a soluble silver complex forming agent to form a silver complex salt, which is reduced on the physical development nuclei to deposit metallic silver, for example, to obtain a silver thin film having a network pattern. it can. On the other hand, silver halide having latent image nuclei that can be developed by exposure is chemically developed in the silver halide emulsion layer to become blackened silver. After development, unnecessary silver halide emulsion layers (including blackened silver), intermediate layers, protective layers and the like are removed, and a silver thin film is exposed on the surface.

  As a method for removing a layer provided on a physical development nucleus layer such as a silver halide emulsion layer after development, there is a method of removing by washing with water or transferring to a release paper. There are two methods for removing the water washing: a method of removing hot water using a scrubbing roller or the like while jetting it with a nozzle or the like, and a method of removing hot water by jetting with a nozzle or the like. In addition, the method of transferring and peeling with a release paper or the like is to squeeze the excess alkali solution (silver complex diffusion transfer developer) on the silver halide emulsion layer in advance with a roller or the like, and remove the silver halide emulsion layer and the release paper. In this method, the silver halide emulsion layer and the like are transferred from a plastic resin film to a release paper and peeled off. 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.

  A developing solution for silver salt diffusion transfer development used in the development processing of the conductive material precursor in the present invention will be described. The developer is an alkaline solution containing a soluble silver complex salt forming agent and a reducing agent. The soluble silver complex salt forming agent is a compound that dissolves silver halide to form a soluble silver complex salt, and the reducing agent is a compound for reducing the soluble silver complex salt to deposit metallic silver on the physical development nucleus. .

  Soluble silver complex forming agents used in the developer include thiosulfates such as sodium thiosulfate and ammonium thiosulfate, thiocyanates such as sodium thiocyanate and ammonium thiocyanate, and sulfites such as sodium sulfite and potassium bisulfite. Salts, oxazolidones, 2-mercaptobenzoic acid and derivatives thereof, cyclic imides such as uracil, alkanolamines, diamines, mesoionic compounds described in JP-A-9-171257, US Pat. No. 5,200,294 Thioethers, 5,5-dialkylhydantoins, alkylsulfones, and others described in the specification, “The Theory of the Photographic Process (4th edition, p474-475)”, T. et al. H. Examples include compounds described in James.

  These soluble silver complex salt forming agents can be used alone or in combination.

  The reducing agent used in the developer is a development known in the field of photographic development as described in Research Disclosure Item 17643 (December 1978) and 18716 (November 1979), 308119 (December 1989). The main drug can be used. For example, polyhydroxybenzenes such as hydroquinone, catechol, pyrogallol, methylhydroquinone, chlorohydroquinone, ascorbic acid and its derivatives, 1-phenyl-4,4-dimethyl-3-pyrazolidone, 1-phenyl-3-pyrazolidone, 1- Examples include 3-pyrazolidones such as phenyl-4-methyl-4-hydroxymethyl-3-pyrazolidone, paramethylaminophenol, paraaminophenol, parahydroxyphenylglycine, paraphenylenediamine, and the like. These reducing agents can be used alone or in combination.

  The content of the soluble silver complex salt forming agent is preferably 0.001 to 5 mol, more preferably 0.005 to 1 mol, per liter of the developer. The content of the reducing agent is preferably from 0.01 to 1 mol, more preferably from 0.05 to 1 mol, per liter of the developer.

  The pH of the developer is preferably 10 or more, and more preferably 11-14. In order to adjust to a desired pH, an alkali agent such as sodium hydroxide or potassium hydroxide, or a buffering agent such as phosphoric acid or carbonic acid is contained alone or in combination. The developer of the present invention preferably contains a preservative such as sodium sulfite or potassium sulfite.

  Further, the silver image of the conductive material obtained by the above development treatment and water washing treatment can be subjected to post-treatment. Examples of the post-treatment liquid include aqueous solutions of reducing substances, water-soluble phosphorus oxoacid compounds, water-soluble halogen compounds, and the like. 2θ = 38.2 ° by X-ray diffraction of the silver image pattern by treating with such a post-treatment liquid at 50 to 70 ° C., more preferably 60 to 70 ° C. for 10 seconds or more, preferably 30 seconds to 3 minutes. If the half-value width is less than 0.35, the conductivity is improved, but the surface resistivity does not change even under high temperature and high humidity, which is preferable.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but it is needless to say that the present invention is not limited by this description.

In order to produce the conductive material precursor, a polyethylene terephthalate film having an undercoat layer containing vinylidene chloride having a total light transmittance of 90% and a thickness of 100 μm was used as a transparent support. Before the physical development nucleus layer was applied, an undercoat layer of 50 mg / m ² of gelatin was applied to the film and dried.

  Next, a palladium sulfide sol solution was prepared as follows, and a physical development nucleus solution was prepared using the obtained sol.

<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 a palladium sulfide sol.

<Physical development nuclear solution composition / m ² >
The palladium sulfide sol 0.4mg
0.08 mL of 2% glutaraldehyde solution

This physical development nuclei solution was applied on the undercoat layer so that the palladium sulfide had a solid content of 0.4 mg / m ² and dried.

Subsequently, a backing layer having the following composition was applied to the surface opposite to the side on which the physical development nucleus layer was applied.
<Backcoat layer composition / per 1 m ² >
2g gelatin
Amorphous silica matting agent (average particle size 5μm) 20mg
Dye 1 200mg
Surfactant (S-1) 400mg

  Subsequently, an intermediate layer, a silver halide emulsion layer, and an outermost layer having the following composition were coated on the physical development nucleus layer in order from the side closer to the support. The silver halide emulsion was prepared by a general double jet mixing method for photographic silver halide emulsions. This silver halide emulsion was prepared with 95 mol% of silver chloride and 5 mol% of silver bromide, and an average grain size of 0.15 μm. The silver halide emulsion thus obtained was 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 gram of silver.

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

<Silver halide emulsion layer composition / 1m ² per>
Gelatin 1.0g
Silver halide emulsion 4.0 g equivalent to silver 1-phenyl-5-mercaptotetrazole 3.0 mg
Surfactant (S-1) 20mg

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

The conductive material precursor thus obtained was subjected to pattern exposure with a close contact printer using a mercury lamp as a light source, and a transparent original having a fine line width of 20 μm and a lattice pattern of 300 μm was brought into close contact. The film was developed by dipping in a later-described diffusion transfer developer at 20 ° C. for 60 seconds, and the appropriate exposure amount at which the fine line width was 20 μm was determined. As a result, it was 6.0 mJ / cm ² near 405 nm. The conductive material precursor was subjected to subexposure by a contact printer with a light amount of 0.36 mJ / cm ² corresponding to 6% of the appropriate exposure amount, and then the transmission original of the mesh pattern was closely contacted to 6.0 mJ / Pattern exposure was performed at cm ² .

  Thereafter, the exposed conductive material precursor was immersed in the following developer at 20 ° C. for 60 seconds, and then the silver halide emulsion layer, intermediate layer, outermost layer and backing layer were removed by washing with warm water at 40 ° C. And dried. A conductive material in which a silver thin film was formed in a mesh pattern was obtained from the exposed sample.

<Diffusion transfer developer composition>
Potassium hydroxide 25g
Hydroquinone 18g
1-phenyl-3-pyrazolidone 2g
Potassium sulfite 80g
N-methylethanolamine 15g
Potassium bromide 1.2g
Bring the total volume to 1000 mL with water.
Adjust to pH = 12.2.

  As a post-treatment of the conductive material on which the mesh-patterned silver thin film obtained as described above was formed, a 15 mass% monosodium phosphate aqueous solution was used for 60 seconds at 60 ° C.

  The following evaluation was carried out on the 50 cm square conductive material on which the mesh-patterned silver thin film obtained as described above was formed.

(1) Surface resistivity Based on JIS-K7194, it measured using the Lorestar GP / ESP probe by Dia Instruments Co., Ltd. The measurement locations were four corners (upper left, lower left, upper right, lower right) and a central portion of a 50 cm square. Further, the desirable surface resistivity is an average value of 400 to 600Ω / □ at five locations, and the difference Δ between the maximum and minimum is within 100Ω / □. The results are shown in Table 1.

(2) Total light transmittance Regarding the light transmittance, the total light transmittance of the mesh pattern silver thin film portion was measured with a double beam type haze computer manufactured by Suga Test Instruments. The measurement location was the center of a 50 cm square. The results are shown in Table 1.

A conductive material was prepared in the same manner as in Example 1 except that the amount of sub-exposure was changed to 0.54 mJ / cm ² , and evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

A conductive material was prepared in the same manner as in Example 1 except that the amount of sub-exposure was changed to 0.78 mJ / cm ² , and evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 1)
A conductive material was prepared in the same manner as in Example 1 except that the sub-exposure was not performed, and evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

  A conductive material was prepared in the same manner as in Example 1 except that the sub-exposure was performed after pattern exposure, and evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

A conductive material was produced in the same manner as in Example 1 except that the amount of sub-exposure was 0.18 mJ / cm ² and before and after pattern exposure, and evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 2)
A conductive material was prepared in the same manner as in Example 1 except that it was exposed with a light amount 1.5 times the appropriate exposure amount for adjusting the surface resistivity without performing sub-exposure, and evaluated in the same manner as in Example 1. Carried out. The results are shown in Table 1.

(Comparative Example 3)
A conductive material was prepared in the same manner as in Example 1 except that it was exposed with a light amount three times the appropriate exposure amount for adjusting the surface resistivity without performing sub-exposure, and evaluation was performed in the same manner as in Example 1. . The results are shown in Table 1.

(Comparative Example 4)
A conductive material was prepared in the same manner as in Example 1 except that a mesh pattern transmission original having a fine line width of 15 μm and a lattice spacing of 300 μm was used for adjusting the surface resistivity without performing sub-exposure. Evaluation was performed. The results are shown in Table 1.

(Comparative Example 5)
A conductive material was prepared in the same manner as in Example 1 except that a mesh pattern transmission original having a fine line width of 10 μm and a lattice spacing of 300 μm was used for adjusting the surface resistivity without performing sub-exposure. Evaluation was performed. The results are shown in Table 1.

(Comparative Example 6)
In the preparation of the conductive material precursor of Example 1, a silver halide emulsion equivalent to 3.0 g / m ² silver was used for the silver halide emulsion layer in order to adjust the surface resistivity, and no subexposure was performed. Except for the above, a conductive material was prepared in the same manner as in Example 1 and evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 7)
In the preparation of the conductive material precursor of Example 1, a silver halide emulsion equivalent to 2.0 g / m ² silver was used for the silver halide emulsion layer in order to adjust the surface resistivity, and no subexposure was performed. Except for the above, a conductive material was prepared in the same manner as in Example 1 and evaluated in the same manner as in Example 1. The results are shown in Table 1.

  As is apparent from the above results, a uniform conductive material having a high surface resistivity can be obtained by the production method of the present invention.

Claims (1)

  A conductive material precursor having at least a physical development nucleus layer and a silver halide emulsion layer in this order on the support is imagewise exposed, and metallic silver is deposited on the physical development nucleus layer by a diffusion transfer method to make the conductive material conductive. In the manufacturing method of the electroconductive material which manufactures material, subexposure is given to the whole surface of an electroconductive material precursor before and / or after image-wise exposure, The manufacturing method of the electroconductive material characterized by the above-mentioned.