JP5632617B2 - Transparent conductive material - Google Patents

Description

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

  In recent years, the demand for transparent conductive materials has been rapidly increasing in applications such as electric circuits, electromagnetic shielding materials, and touch panels. In particular, the demand for resistive touch panels is increasing more than before.

  As a method for producing a transparent conductive material, a conductive metal such as silver, copper, nickel, or indium is formed on a transparent resin film by sputtering, ion plating, ion beam assist, vacuum deposition, or wet coating. A method of forming a thin film is generally used. Amid the growing demand for transparent conductive materials, there is a problem of depletion of mineral resources such as indium, etc., and a low-cost and high-productivity manufacturing method is required.

  As performance required for the transparent conductive material, there are conductivity and light transmittance. However, a metal thin film with a certain film thickness is necessary to increase the conductivity, and there is a problem in that the transmittance is lowered. Therefore, a transparent conductive film having high conductivity and high light transmittance is required. As such a transparent conductive material, a thin metal wire is formed in a mesh pattern on a light-transmitting support, and by adjusting the line width and pitch of the fine metal wire, and the pattern shape, etc., a high light transmittance is achieved. A conductive material that maintains the rate and imparts high conductivity is known.

  Various patterns have been introduced regarding the shape of the metal fine wire mesh pattern. In Japanese Patent Application Laid-Open No. 10-41682 (Patent Document 1), a triangle such as a regular triangle, an isosceles triangle, a right triangle, a square, a rectangle, a rhombus, a parallelogram, a trapezoid, or the like, a (positive) hexagon, ) The pattern is a combination of (positive) n-gon, such as octagon, (positive) dodecagon, (positive) icosahedron, etc. The combination pattern is disclosed. International Publication No. 2006/040989 pamphlet (Patent Document 2) discloses a pattern in which a conductive portion having an irregular network structure is present. Japanese Patent Application Laid-Open No. 2002-223095 (Patent Document 3) discloses a striped pattern and a brickwork pattern. Among these patterns, square, rhombus and regular hexagonal patterns are frequently used. As for the line width of the metal mesh pattern, a thin metal wire of about 1 to 50 μm is used in consideration of conductivity, light transmittance, and the like. The pitch is similarly set to about 100 to 1000 μm. Regarding the line width and pitch of the metal mesh pattern, preferred ranges for each invention are described in many published patent publications and the like.

  Examples of a method for producing a transparent conductive material having a mesh pattern-shaped fine metal wire on a light-transmitting support include 1) 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) Applying a mask with a desired pattern and irradiating with ultraviolet rays, etc. 4) Curing the photoresist agent 5) After removing the uncured portion, 6) A method of removing an unnecessary conductive material portion by chemical etching or the like to form an electric circuit (subtractive method), 1) applying an electroless plating catalyst to an insulating substrate, 2) applying a photoresist agent, Exposure and development, 3) Electroless plating to form a conductive pattern, 4) Method of removing plating resist (full additive method), or 1) Electroless plating catalyst applied to insulating substrate Electroless plating, 2) Applying a photoresist agent, exposure and development, 3) Electrolytic plating, forming a conductive pattern, 4) Method of peeling plating resist, etc. (semi-additive method), etc. Is also known.

  In addition, as a method for producing 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 or an ink jet printing method, and sintering, or an electroless plating catalyst is used. A method is known in which an electric circuit is formed by printing a paste having a substrate on a substrate by a screen printing method, an ink jet printing method, or the like, and performing electroless plating.

  In view of making a uniform and high-definition pattern easily and stably, a method using a silver salt photographic light-sensitive material having a silver halide emulsion layer as a conductive material precursor has been proposed in recent years. For example, in International Publication No. 2001/51276 pamphlet (Patent Document 4) and Japanese Patent Application Laid-Open No. 2004-221564 (Patent Document 5), a silver salt photographic light-sensitive material is subjected to 1) image exposure and development treatment, and 2) metal plating treatment. The proposal of the method of manufacturing an electroconductive material by making is performed. Similarly, a method using a silver salt diffusion transfer method has also been proposed as a method using a silver salt photosensitive material, for example, Japanese Patent Application Laid-Open No. 2003-77350 (Patent Document 6). 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.

  Although the metal mesh pattern produced by such a manufacturing method can be produced at a relatively low cost, the transparent conductive material has high conductivity and low surface resistivity. It is difficult to adjust the surface resistivity for application. In the analog resistive touch panel, since it is necessary to recognize a fine coordinate position, a certain amount of resistance is required for the transparent conductive material used for the electrode.

  In order to increase the surface resistivity of the transparent conductive material having a metal mesh pattern, there is a method of increasing the pitch of the mesh pattern. When the pitch of the mesh pattern is increased, the surface resistivity of the transparent conductive material is increased and the light transmittance is improved, but there is a problem that the presence of the mesh pattern metal fine wire can be recognized. Usually, since the touch panel is installed on a display such as an LCD, if the visibility of the mesh pattern fine metal wire is increased, the fine metal wire is conspicuous on the image displayed on the display, which is not preferable.

  As another method of increasing the surface resistivity, there are a method of reducing the line width of the mesh pattern and a method of reducing the metal film thickness. For example, in a subtractive method using a photoresist agent, a semi-additive method, or the like, the surface resistivity can be increased by adjusting the line width of the exposure mask or adjusting the strength of chemical etching. In the method using the screen printing method or the ink jet printing method, the surface resistivity can be increased by adjusting the amount of the metal paste by adjusting the line width of the printing plate or adjusting the ink discharge amount. When printing a plating catalyst, the surface resistivity can be increased by adjusting the amount of electroless plating. In the method of performing metal plating on the silver salt photographic light-sensitive material, the surface resistivity can be increased by adjusting the amount of metal plating. Furthermore, in the method using the silver salt diffusion transfer method, the surface resistivity can be increased by adjusting the line width of the mask or adjusting the exposure time.

  However, if the surface resistivity is increased by reducing the line width as described above or by reducing the metal film thickness, a slight exposure amount flare, metal paste amount flare, metal plating amount flare, etc. May cause a partial difference in surface resistivity (rate of change), and the resulting transparent conductive material often has non-uniform surface resistivity within the material. If such a conductive material is applied to, for example, an electrode for a resistive touch panel, it is not preferable because an accurate coordinate position cannot be recognized. For this reason, there has been a demand for a transparent conductive material that is suitable as an electrode material for, for example, an analog resistive film type touch panel, has high surface resistivity, is uniform, and has low visibility of fine mesh wires.

Japanese Patent Laid-Open No. 10-41682 International Publication No. 2006/040989 JP 2002-223095 A International Publication No. 2001/51276 Pamphlet JP 2004-221564 A JP 2003-77350 A

  Accordingly, an object of the present invention is to provide a transparent conductive material having high surface resistivity, high uniformity of surface resistivity depending on the location, and low visibility of mesh fine lines.

The above object of the present invention is achieved by the following invention.
(1) Yes and mesh pattern made of a metal thin wire electrical resistance on the light transmissive support is 5kΩ / cm~500kΩ / cm, a pattern composed of a thin line having more than five times the electrical resistance of the metal thin wires And a thin metal wire forming the mesh pattern, and a transparent conductive material having a line width of 1 to 50 μm , the wire having an electric resistance of 5 times or more that of the metal wire .

  According to the present invention, it is possible to provide a transparent conductive material that is suitable as an electrode material for, for example, a resistive touch panel, has a relatively high surface resistivity, is uniform, and has low visibility of fine mesh wires.

An example of the mesh pattern of the present invention Components of the mesh pattern in Fig. 1 (high conductive lines) Components of the mesh pattern in FIG. 1 (pattern composed of low conductive lines) 2 fine metal wire, mesh pattern of pitch of FIG. An example of the mesh pattern of the present invention Components of the mesh pattern in FIG. 5 (high conductive lines) Components of the mesh pattern in FIG. 5 (pattern composed of low conductive lines) 6 fine metal wire, mesh pattern of pitch of FIG.

  The transparent conductive material of the present invention is characterized by its fine metal wire pattern, a mesh pattern composed of fine metal wires contributing to surface resistivity, and a fine wire having substantially higher electric resistance than the fine metal wires and substantially not contributing to surface resistivity. And a mesh pattern. Hereinafter, a mesh pattern made of fine metal wires contributing to surface resistivity is referred to as a high conductive wire, and a thin wire that does not substantially contribute to surface resistivity is referred to as a low conductive wire.

  The mesh pattern of the transparent conductive material of the present invention has a mesh pattern as shown in FIGS. 1 and 5, for example. In FIG. 1, x is the pitch of the mesh pattern, a is a fine metal wire forming a high conductive line, and b is a low conductive line. Since the surface resistivity of the pattern formed by b is higher than the surface resistivity of the high conductive line formed by a, the surface resistivity of the transparent conductive material of the present invention is mainly determined by the high conductive line, Low conductive lines do not substantially contribute to surface resistivity. Here, “substantially” means a mesh pattern (FIG. 1) in which the surface resistivity of the mesh pattern of the present invention (corresponding to FIG. 1) formed of a high conductive line and a low conductive line is composed only of the high conductive line. 2) (corresponding to 2) of the surface resistivity value. For example, when the surface resistivity of the high conductive wire is 500Ω / □, the surface resistivity of the mesh pattern of the present invention is preferably 300 to 500Ω / □.

  In the present invention, the electrical resistance per unit length of the fine metal wire a forming the high conductive wire is preferably 5 kΩ / cm to 500 kΩ / cm. The thin wire b, which is a low conductive wire, shows a value larger than the resistance per unit length of a, and is preferably 5 times or more, more preferably 10 times or more the electrical resistance of a.

  In the present invention, the high conductive line is a mesh pattern having a certain pitch composed of a. For example, if the high conductive line has a pitch of 300 μm, the surface resistivity is preferably 1 to 300Ω / □. . In the present invention, a conductive material having a surface resistivity of 100 to 1000 Ω / □ can be obtained by adjusting the pitch of the fine metal mesh pattern.

  In the present invention, the pitch of the high conductive wire is preferably 200 μm to 5000 μm. By increasing the pitch of the high conductive wire, the value of the surface resistivity of the transparent conductive material can be increased. However, the visibility of the metal fine wire pattern is increased by increasing the pitch. In order to avoid this, a low conductive line (corresponding to FIG. 3) is superimposed on a high conductive line.

  1 which is an example of the mesh pattern of the transparent conductive material of the present invention will be described in detail. The mesh pattern of FIG. 1 is a mesh pattern having a pitch that is ½ of the pitch of the high conductive line of FIG. 2 by drawing the low conductive line of FIG. 3 between the pitches of the high conductive line of FIG. is there. 2a is a fine metal wire forming a highly conductive line, and the pitch y is twice the pitch x of FIG. 1 and 2x. B in FIG. 3 is a low conductive line, and the pitch of the low conductive line is y, similar to the pitch of the high conductive line in FIG. The mesh pattern in FIG. 2 can obtain a higher surface resistivity because the pitch is doubled than the high-conductivity line having the pitch x shown in FIG. 4, but the visibility of the fine metal wires is increased by increasing the pitch. Tend. On the other hand, the mesh pattern of FIG. 1 according to the present invention has a surface resistivity substantially equal to that of the mesh pattern of FIG. 2, and the visibility does not increase like the mesh pattern of FIG.

  Similarly, FIG. 5 which is an example of the mesh pattern of the transparent conductive material of the present invention will be described in detail. The metal mesh pattern shown in FIG. 5 is composed of the mesh patterns shown in FIGS. 6 of the mesh pattern of FIG. 6 is a metal fine wire which forms a highly conductive line, and the pitch z is 3 times the pitch x of FIG. 5 and 3x. 7 in the mesh pattern in FIG. 7 is a low conductive line, and the pitch is in the form of alternating x and 2x. The high conductivity line of FIG. 6 can have a higher surface resistivity than the high conductivity line of the pitch x shown in FIG. The high conductive wire in FIG. 6 has a pitch three times that of the high conductive wire in FIG. 8, so that a high surface resistivity can be obtained, but the visibility of the metal thin wire tends to increase. Therefore, by combining the low conductive wires in FIG. 7, high surface resistivity can be obtained without increasing the visibility of the fine metal wires.

  In the mesh pattern of the transparent conductive material of the present invention, the arrangement of the thin metal wires and the low conductive wires forming the high conductive wires can be arbitrarily selected. For example, FIG. 1 is alternately arranged at a ratio of metal thin wires 1 and low conductive lines 1 forming high conductive lines, and FIG. 5 is arranged at a ratio of metal thin wires 1 and low conductive lines 2 forming high conductive lines. doing. In addition, the low conductive line 3 for the high conductive line 1, the low conductive line 4 for the high conductive line 1, the low conductive line 1 for the high conductive line 2, the low conductive line 3 for the high conductive line 2, Low conductive line 5 for high conductive line 2, Low conductive line 1 for high conductive line 3, Low conductive line 2 for high conductive line 3, Low conductive line 4 for high conductive line 3, High conductive line A high conductive line and a low conductive line can be arbitrarily combined with the line 3 in accordance with a desired surface resistivity such as the low conductive line 5. A preferred combination is a combination in which the ratio of the low conductive wire is 1 or more with respect to the thin metal wire 1 forming the high conductive wire.

  The pitch of the mesh pattern of the transparent conductive material of the present invention (including the mesh pattern composed of fine metal wires forming the high conductive line and the low conductive line) is preferably 50 to 1000 μm, and more preferably 100 to 500 μm. If the pitch becomes too dense, the light transmittance may decrease as a transparent conductive material. If the pitch becomes too coarse, fine metal wires can be visually recognized, which may impair the aesthetic appearance of the transparent conductive material.

  The line widths of the fine metal wire and the low conductive wire forming the high conductive wire of the transparent conductive material of the present invention can be arbitrarily determined, but are preferably 1 to 50 μm, and more preferably 5 to 30 μm. When the line width is increased, the light transmittance may be reduced, and the visibility of the fine metal wire may be increased.

  The film thickness of the thin metal wire and the low conductive wire forming the high conductive wire of the transparent conductive material of the present invention is preferably 0.01 to 20 μm, more preferably 0.1 to 10 μm.

  In the present invention, examples of a method for producing a low conductive line include adjustment of line width and adjustment of film thickness. Moreover, when providing a low conductive wire by printing, the metal ratio in the paste can be reduced, or printing can be performed using a non-metal containing paste such as carbon black instead of metal. As a guideline, the line width and film thickness of the low conductive line are 50 to 100% in terms of line width and 0.01 to 100% in terms of film thickness, as compared with the thin metal wire forming the high conductive line. If it is less than this, the aesthetic appearance may be impaired due to a sense of discomfort when the transparent conductive material is visually observed. The low conductive line may be an insulator.

  The shape of the fine wire mesh pattern of the transparent conductive material of the present invention is preferably a square, a rhombus, a (regular) hexagon, or the like.

  Examples of the light transmissive support of the transparent conductive material 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. A light transmissive support such as a plastic resin film is used. Here, the light transmittance means that the total light transmittance is 80% or more. These may be colored to such an extent that they do not interfere with the object of the present invention, and these various light-transmitting supports can be used alone, but a laminate obtained by combining them may also be used. The thickness of the light transmissive support is preferably 5 to 300 μm.

  As a metal used for the thin wire pattern of the conductive material of the present invention, one or more metals among metals such as copper, aluminum, nickel, iron, gold, silver, stainless steel, tungsten, chromium, titanium, etc. Alternatively, an alloy in which two or more kinds are combined can be used.

  In the transparent conductive material of the present invention, the surface resistivity can be arbitrarily set. For example, for an analog resistive film type touch panel, 100 to 1000Ω / □ is preferable.

  In the transparent conductive material of the present invention, as a method of forming a fine metal wire pattern on a support, a method of forming an image using a photoresist agent such as a subtractive method, a full additive method, a semi-additive method, or a metal paste is supported. A method of printing on a body by a screen printing method, an ink jet printing method, or the like, a method of sintering, a method of printing a paste having an electroless plating catalyst on a substrate by a screen printing method, an ink jet printing method, or the like, and applying electroless plating There are a method of plating an image obtained from a silver salt photographic light-sensitive material, a method of using a silver salt diffusion transfer method, and the like.

  Among them, in order to form a mesh pattern with a high conductive line and a low conductive line, which is a feature of the transparent conductive material of the present invention, from the viewpoint that a uniform and high-definition pattern can be made easily and stably. A method using a silver salt diffusion transfer method is preferred. A method for forming a fine metal wire pattern by a silver salt diffusion transfer method, which is preferably used for producing the transparent conductive material of the present invention, will be described below.

  In the method for producing a transparent conductive material by the silver salt diffusion transfer method, after the transparent conductive material precursor is imagewise exposed, metallic silver is deposited by silver salt diffusion transfer development. The conductive material precursor 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. In addition, the support body which a transparent conductive material precursor has is synonymous with the light transmissive support body of the above-mentioned transparent conductive material, and the support body which this precursor has is equivalent to the light transmissive support body of this invention. To do.

As the physical development nuclei contained in the physical development nuclei layer of the conductive material precursor, fine particles (particle size is about 1 to several tens of nm) made of heavy metals or sulfides 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 can also contain a water-soluble polymer compound. When the water-soluble polymer compound is used, the addition amount is preferably about 0 to 500% by mass relative to the physical development nucleus. Examples of the water-soluble polymer compound include gum arabic, cellulose, sodium alginate, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamide, a copolymer of acrylamide and vinyl imidazole, and the like.

  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 an 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 usedAmong 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, 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.

  For formation of silver halide emulsion grains used in the silver halide emulsion layer, Research Disclosure Item 17643 (December 1978) and 18716 (November 1979), 308119 (such as forward mixing, reverse mixing, and simultaneous mixing) are used. (December 1989) can be used. Of these, the so-called controlled double jet method, which is one of the simultaneous mixing methods and keeps pAg in the liquid phase in which the grains are formed, is preferable from the viewpoint of obtaining silver halide emulsion grains having a uniform particle diameter. 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 salt thereof, iridium salt or complex salt thereof, in the process of silver halide grain formation 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 industry 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) and 308119 (December 1989) or cited.

  In the conductive material precursor, 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 containing a water-soluble polymer compound as a main binder. As the water-soluble polymer compound mentioned here, any compound can be selected as long as it easily swells with the developer and allows the developer to easily penetrate into the lower silver halide emulsion layer and the physical development nucleus layer.

  Specifically, gelatin, albumin, casein, polyvinyl alcohol, or the like can be used. Particularly preferred water-soluble polymer compounds 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.

As the conductive material precursor, 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. An 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, but for example, when it is contained in the backing layer as an antihalation agent, the range of about 20 mg to about 1 g per 1 m ² is desirable, preferably maximum The absorbance at the absorption wavelength is 0.5 or more.

  A method for producing the conductive material of the present invention using the conductive material precursor will be described. A mesh pattern drawn with a high conductive line and a low conductive line, which is a feature of the transparent conductive material of the present invention, is formed from the conductive material precursor. The conductive material precursor described above is exposed imagewise (mesh patterns with different line widths and film thicknesses to be high and low conductive lines), then processed with a diffusion transfer developer, and then on the physical development nucleus layer. Unnecessary layers are removed by washing with water to obtain the mesh pattern of the present invention.

  The exposure of the conductive material precursor will be described. When the high conductive line and the low conductive line are formed with different line widths, the silver halide emulsion layer of the conductive material precursor is exposed imagewise, but as an exposure method, the high conductive line and the low conductive line are different. A method in which a transparent original having a line width and a silver halide emulsion layer are in close contact with each other for exposure, or a mesh pattern having different line widths to be high and low conductive lines is scanned and exposed using various laser beams. There are methods.

  Further, in the method of changing the line width and film thickness of the high conductive line portion and the low conductive line portion depending on the exposure amount, the transmission original and the silver halide emulsion layer having different transmission densities of the high conductive line portion and the low conductive line portion are used. The method of exposing with close contact, the method of performing exposure by using two types of transmission originals with close contact with the silver halide emulsion layer, or using various laser beams For example, there is a method of irradiating the high conductive line portion and the low conductive line portion with different amounts of light and scanning and exposing mesh patterns having different line widths and film thicknesses.

  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.

  A method of using two types of transparent originals in the method of forming a high conductive line and a low conductive line with a difference in exposure amount will be described below. In the case of producing a mesh pattern alternately arranged at a ratio of the fine metal wires 1 and the low conductivity wires 1 forming the high conductive lines as shown in FIG. 1, two kinds of transparent original masks having the mesh patterns of FIGS. 2 and 4 are used. By using it, a conductive material precursor having an exposed part (light transmission part after development processing), an unexposed part (high conductive line part after development process) and a small amount of exposed part (low conductive line part after development process) is produced. To do.

  The masks are overlaid so that the fine lines of these masks overlap (the thin line in FIG. 2 overlaps one of the thin lines in FIG. 4), and a pin bar hole used for alignment is made. At this time, if marks such as register marks for alignment are put in advance at the four corners of the mask, superposition can be easily performed. A similar hole is made in the conductive material precursor to be used. First, a pin bar is installed on the exposure surface. The mask having the mesh pattern shown in FIG. 4 and the film surface on the side having the silver halide emulsion layer of the conductive material precursor are fixed with a pin bar so that the film surfaces are in close contact with each other (hereinafter, first exposure). Next, the mask having the mesh pattern of FIG. 2 and the film surface on the side having the silver halide emulsion layer of the conductive material precursor subjected to the first exposure are fixed with a pin bar so that the film surfaces are in close contact with each other (hereinafter referred to as the first pattern). 2 exposure). A high conductive line is formed by the first exposure, and a low conductive line is formed by the second exposure. The amount of light for the second exposure is such that when processed with a diffusion transfer developer, a portion of the exposed silver halide forms a silver image on the physical development nucleus layer by diffusion transfer.

  A development process using a silver salt diffusion transfer developer of a conductive material precursor will be described. The silver halide emulsion layer of the conductive material precursor exposed imagewise as described above undergoes physical development by processing with a silver salt diffusion transfer developer, and has latent image nuclei that can be developed. Silver halide is dissolved in a soluble silver complex salt forming agent to form a silver complex salt, which is reduced on the physical development nuclei to precipitate metallic silver. For example, a silver thin film having a mesh pattern can be obtained. 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 a hot water shower, or 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 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 hydrogen sulfite. 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.

  In addition, the silver image of the conductive material obtained by the development treatment and the water washing treatment can be subjected to post-treatment. Examples of the post-treatment liquid include aqueous solutions of a reducing substance, a water-soluble phosphorus oxo acid compound, a water-soluble halogen compound, and the like. If the post-treatment liquid is used for treatment at 50 to 70 ° C., more preferably 60 to 70 ° C. for 10 seconds or longer, and preferably 30 seconds to 3 minutes, the conductivity is improved. However, it is preferable because the surface resistivity does not change.

  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.

Example 1
30 cm square exposure masks (transmission originals) 1 to 10 for preparing the mesh pattern of the present invention were prepared. Table 1 shows the prepared exposure masks (transmission originals) 1 to 10.

  The transparent original 1 has a mesh pattern with a pitch of 300 μm and a line width of 18 μm, and the transparent originals 2 and 3 have a pitch doubled or tripled with respect to the transparent original 1. The transparent originals 4, 5, and 6 are mesh patterns having a pitch of 300 μm and line widths of 12 μm, 14 μm, and 16 μm, respectively. The transparent original 7 has a mesh pattern with a pitch of 300 μm, but is a transparent original as shown in FIG. 1 in which 18 μm and 12 μm are alternately arranged. The transparent original 8 is a transparent original as shown in FIG. 1 in which 18 μm and 14 μm are alternately arranged. Similarly, the transparent original 9 is a transparent original as shown in FIG. 1 in which 18 μm and 16 μm are alternately arranged. The transparent original 10 is also a 300 μm pitch mesh pattern, but is a transparent original as shown in FIG. 5 that repeats 18 μm, 12 μm, and 12 μm.

  Separately from the original document shown in Table 1, transparent originals were produced by connecting the left and right solid portions at 1 cm intervals with the line width shown in Table 2.

Next, a conductive material precursor was prepared. As the light transmissive support, a polyethylene terephthalate film which was subjected to easy adhesion processing with a layer containing vinylidene chloride having a total light transmittance of 90% and a thickness of 100 μm was used. Before the physical development core 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 palladium sulfide sol.

<Physical development nuclei solution composition / 1 m ² per>
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 palladium sulfide was 0.4 mg / m ² in solid content, 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.
<Undercoat 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 / per 1 m ² >
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 exposed by closely contacting the transmission originals s1 to s4 previously produced by a contact printer using a mercury lamp as a light source. The exposure amount was such that the thin line width of the transparent conductive material was the same as the thin line width of the transparent original.

  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. From the exposed sample, a transparent conductive material on which a silver thin film similar to a transparent original was formed was obtained. When the fine line width of the obtained fine line image was confirmed with an optical microscope, it was the same as the fine line width of the exposure mask.

<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 transparent 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 electric resistance of the obtained image was measured using a commercially available tester. These results are shown in Table 3.

  A conductive material was produced using transparent originals 1 to 10 in the same manner as described above. When the fine line width and pitch of the obtained mesh pattern image were confirmed with an optical microscope, they were the same as the fine line width and pitch of the exposure mask. Moreover, the fine wire film thickness of the mesh pattern was measured with the confocal microscope, and it confirmed that all the samples were substantially the same.

  Next, the following evaluation was performed on the 30 cm square conductive material on which the mesh-patterned silver thin film obtained from the transparent originals 1 to 10 was formed.

(1) Average value of surface resistivity and in-plane uniformity Based on JIS-K7194, it was measured using a Lorester GP / ESP probe manufactured by Dia Instruments Co., Ltd. The measurement locations were four corners (upper left, lower left, upper right, lower right) and five central portions of a 30 cm square. Table 4 shows the average value (Ω / □) of the measurement results. In addition, the ratio (%) of the difference between the maximum value and the minimum value with respect to the average value was used as an index representing in-plane uniformity. These values are also shown in Table 4. The average value of the surface resistivity was allowed to be 100 to 1000Ω / □, and the ratio (%) between the maximum value and the minimum value with respect to the average value of the surface resistivity was allowed to be within 20%.

(2) Visibility of fine metal wires and surface texture The obtained transparent conductive material was visually observed from a position 50 cm away on a light table, and the appearance quality was evaluated. Evaluation items are the visibility of fine metal wires and the texture of the surface of the transparent conductive material. All are evaluated in 5 stages, and the visibility of the fine metal wire is as follows: 1: the best level at which the fine metal wire is hardly visible, 2: the level at which the fine metal wire is slightly visible by staring, 3: the metal by staring. The level at which the fine line can be visually recognized, 4: the level at which the fine metal line can be visually recognized at a glance, and 5: the worst level at which the visibility of the fine metal line is high. 1 and 2 were defined as acceptable, and 3 to 5 as unacceptable levels. The results are shown in Table 4. Regarding the texture of the surface, it is 1: the best level that is uniform and has no rough feeling, 2: the level that is not uniform when staring, but the level that does not feel rough, 3: the level that feels rough when staring, 4: the glance The level which feels rough and 5: The rough feeling is strong and is defined as the worst level. Similarly, 1 and 2 were defined as acceptable, and 3 to 5 as unacceptable levels. These results are shown in Table 4.

(Example 2)
Using the transparent original s1, the first exposure was performed with the same light amount as in Example 1, and then the second exposure was performed with a light amount of 50% of the first exposure through a film on which no pattern was drawn. Otherwise, a transparent conductive material was produced in the same manner as in Example 1. As in Example 1, when the electrical resistance was measured with a tester, it was 1560 kΩ / cm.

  Next, the first exposure is performed using the transparent original 1 with the same light amount as the first exposure, and then the second exposure is performed using the transparent original 2 with the same light amount as the second exposure. A transparent conductive material having a conductive line and a low conductive line was produced. Others were produced in the same manner as in Example 1, and evaluated in the same manner as in Example 1. When the fine line width and pitch of the obtained mesh pattern image were confirmed with an optical microscope, the pitch was 300 μm, and the line width was about 18 μm for both the high and low conductive lines. Further, when the film thickness of the line was measured with a confocal microscope, the high conductive line was almost the same as Sample 1, and the low conductive line was thinner than the thin line forming the high conductive line, and was about 60 to 70%. It was confirmed (Sample 11).

  For comparison, the transparent original 1 is used for the first exposure, followed by exposure with the same amount of light as that of the second exposure through a film on which no pattern is drawn, and a transparent conductive material having only low conductive lines is produced. Evaluation was carried out in the same manner as in Example 1. The film thickness of the wire was almost the same as the low conductive wire of the transparent conductive material (Sample 12). These results are shown in Table 5.

  From the results of Tables 4 and 5, the effectiveness of the present invention can be understood.

  As is clear from the above results, the present invention provides a transparent conductive material having high surface resistivity and uniformity, and further low visibility of fine mesh wires.

  The mesh pattern of the present invention is useful as a method for changing the surface resistivity of a transparent conductive film while maintaining in-plane uniformity.

a Metal thin wire forming high conductive wire b Low conductive wire x Pitch y Pitch z Pitch

Claims (1)

On the light transmissive support, has a pattern composed of a mesh pattern composed of fine metal wires having an electric resistance of 5 kΩ / cm to 500 kΩ / cm , and fine wires having an electric resistance of 5 times or more that of the fine metal wires , A thin metal wire forming a mesh pattern, and a transparent conductive material having a line width of 1 to 50 μm , which has an electric resistance of 5 times or more that of the metal wire .

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