JP4570436B2 - Metal mesh and wiring pattern transfer sheet - Google Patents

Description

  The present invention relates to a metal mesh and a wiring pattern, and more particularly to a metal mesh that is made of fine wires and has high light transmittance and is self-supporting, and a fine wiring pattern transfer sheet that can be transferred to various supports.

  In recent years, since advanced use of electromagnetic waves such as wireless networks and RF-IDs has become active, EMC countermeasures for electronic devices and the like have become urgent. Among them, there is an increasing demand for a shielding material having transparency for use in plasma display panels and window glass. For such applications, a wire mesh knitted in a metal wire or a metal wire mesh formed on a transparent base material such as polyester is used when particularly high transparency is required.

  As a method for forming such a fine metal mesh, a method is generally used in which a photoresist is applied to a metal foil affixed or formed on a resin, imagewise exposed, and then developed, etched, and resist stripped. is there. Further, for example, Japanese Patent Laid-Open No. 2000-196285 discloses a method of forming a conductive pattern by printing a conductive paste and performing electroless plating. Japanese Patent Laid-Open No. 2000-261186 discloses a method in which metal particles for electroless plating catalyst are uniformly provided on the surface of a support and a photoresist layer is further provided thereon, followed by pattern formation by a wet process. A method of forming a conductive pattern by electrolytic plating or resist stripping is disclosed.

  However, it is difficult to form a self-supporting fine wire metal mesh by any of the above methods. As a technique for forming a self-supporting mesh, Patent Document 1 discloses a method using a photoresist. However, since the process is complicated and thinning is limited to metal foil, it is self-supporting. There has been a strong demand for obtaining a thin metal mesh with a simple method.

  In recent years, electronic devices have been miniaturized, and in order to realize these, it is necessary to increase the number of printed circuit boards and the density of circuits. For this purpose, a multilayer wiring board is produced by a method called a build-up method. This is because a circuit pattern is formed by laminating an insulating layer and a copper foil on a substrate having a circuit pattern, and electrical connection is made between the layers via via holes. By repeating this, a multilayered wiring substrate is obtained.

In order to obtain a fine pattern by this method, it is disclosed in Patent Document 2 on an insulating layer to be laminated. Although a method for directly transferring a circuit pattern has been disclosed, the creation of a transfer sheet requires a complicated process, and improvements are required such that the film thickness is limited to the thickness of the metal foil.
JP 2002-275661 A Japanese Patent Laid-Open No. 10-178255

  An object of the present invention is to provide a thin metal metal mesh that is self-supporting in an easy process. Another object of the present invention is to provide a fine wiring pattern transfer sheet capable of transferring a thin metal pattern to another support using an adhesive in an easy process.

  1. A silver fine wire lattice image formed by silver halide diffusion transfer method is plated with a metal on a support having a protein-containing undercoat layer, and a solution containing a proteolytic enzyme is allowed to act thereon. A self-supporting fine metal mesh obtained by peeling an image from a support.

  2. On a support having a protein-containing undercoat layer, a fine silver wiring pattern formed by silver halide diffusion transfer method is plated with a metal, and a solution containing a proteolytic enzyme is allowed to act thereon, so that the plated metal fine wiring A fine wiring pattern transfer sheet capable of transferring a pattern to another support using an adhesive.

  According to the present invention, it is possible to provide a self-supporting metal mesh which is a thin layer and is made of a thin line and has a high light transmittance by a simple method. In addition, a fine wiring pattern transfer sheet that can transfer a fine metal wiring to another support with a thin layer using an adhesive can be provided by a simple method.

  Hereinafter, the present invention will be described in detail. In the present invention, the silver fine wire lattice image and the fine silver wiring pattern are formed by a silver halide diffusion transfer method. As described in JP-A-2003-77350, the method for forming a conductive silver film by this technique is provided with a layer containing a heavy metal such as palladium or a sulfide thereof as a physical development nucleus in advance on a support, A silver halide emulsion layer is provided thereon. By subjecting the silver halide emulsion layer to imagewise exposure and processing with an alkaline developer containing a soluble silver complex salt forming agent and a reducing agent, the silver ions supplied from the unexposed silver halide emulsion are physically developed. A conductive silver film is deposited on the nucleus to form an image.

In the present invention, the support has a protein-containing subbing layer. Specifically, gelatin, albumin, casein or a mixture thereof is preferably used. The amount of protein in the layer is preferably 10 to 300 mg per 1 m ² . In the present invention, the physical development nuclei may be previously contained in the protein-containing undercoat layer, or even if the protein-containing undercoat layer is impregnated after coating, the physical development nuclei are contained on the undercoat layer. A layer may be provided.

  Specific examples of the resin support used in the present invention include polyester resins such as polyethylene terephthalate and polyethylene naphthalate, cellulose resins such as triacetyl cellulose and diacetyl cellulose, polycarbonate resins, and polyimide resins. In order to provide a protein-containing undercoat layer on these supports, an easy-adhesion layer containing polyvinylidene chloride having a hydrophilic group, polyurethane, or the like may be provided in advance. Moreover, it is preferable to perform a discharge treatment before providing the protein-containing undercoat layer. Examples of the discharge treatment include corona discharge treatment, plasma discharge treatment, atmospheric pressure glow discharge treatment, and the like, but it is particularly preferable to perform corona discharge treatment with high in-line treatment and high uniformity.

  In the present invention, the obtained silver fine wire lattice image and fine silver wiring pattern are plated with metal. The type of metal is selected according to the purpose and is not particularly limited, and examples thereof include gold, silver, copper, tin, nickel, chromium, and alloys thereof. The plating layer may have a multilayer structure. Although the thickness of the plating can be arbitrarily selected according to the purpose, it is preferably 0.5 microns or more, more preferably 1 to 6 microns in order to form a free-standing film or to be transferred without being destroyed.

  There is no particular limitation on the plating method, and electroplating and electroless plating are selected when the whole is conductive like a lattice pattern, and electroless plating is selected when the wiring pattern has an electrically isolated portion. It is. Specific plating methods are described in detail in, for example, “Latest Surface Treatment Technology Overview” published by Industrial Technology Service Center Co., Ltd. (first edition, December 21, 1987).

  In the present invention, the sheet having the plated image on the protein-containing subbing layer has a bonding force between the plated image and the support by the action of a solution containing a proteolytic enzyme (hereinafter referred to as an enzyme solution). Is weakened. This proteolytic enzyme is a plant or animal enzyme that can hydrolyze proteins such as gelatin, and known ones are used. Examples include pepsin, rennin, trypsin, chymotrypsin, cathepsin, papain, ficin, thrombin, renin, collagenase, bromelain, bacterial proteinase and the like. Of these, trypsin, papain, ficin, and bacterial proteinase are particularly preferable. The content of the enzyme in the enzyme solution is suitably about 0.2 to 10 g / L.

  In addition to the above enzyme, this enzyme solution can contain a pH buffer, an antibacterial compound, a wetting agent, a preservative, and the like as necessary. The pH of the enzyme solution is selected by experiment so as to obtain the maximum function of the enzyme, but is generally preferably 5 to 7. The temperature of the enzyme solution is also preferably a temperature at which the action of the enzyme is increased, specifically 25 to 45 ° C. In order to make the enzyme solution act, there are methods such as immersing the sheet in the enzyme solution, placing excess liquid on the sheet, or spraying the sheet in a spray form.

  In the case of producing a self-supporting film, the support film and the self-supporting film can be separated by sticking the lead film to both sides of the sheet edge and carefully drawing the two lead films. In this case, this operation may be performed after the enzyme solution is acted, washed with water and dried, or may be peeled off in the enzyme solution. To transfer to another support, apply UV curable resin to the sheet, press it to the other support, and irradiate the sheet with UV light from the opposite side of the metal to peel the metal and support. Or a method in which a butyral resin or the like is applied to another support and thermocompression bonded together with the sheet of the present invention, and then the metal and the support are peeled off.

  Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention is not limited to these examples.

The following undercoat layers were provided on both sides of a polyethylene terephthalate film having a thickness of 100 microns. All parts are in terms of solid mass.
Undercoat first layer: vinylidene chloride latex (manufactured by Asahi Kasei Corporation, L-536B, vinylidene content 90% or more), 100 parts, dry film thickness 0.3 microns.
Undercoat second layer: lime-processed gelatin, 100 parts, dry film thickness 0.15 microns.

First, an antihalation layer coating solution containing a dye having an absorption maximum at the exposure wavelength was applied onto the polyethylene terephthalate film having an undercoat layer prepared as described above. Subsequently, the following physical development nucleus layer coating solution was applied to the opposite side of the antihalation layer so that palladium sulfide was 0.4 mg / m ² in solid content, and dried.
<Preparation of palladium sulfide sol>
Liquid A Palladium chloride 5g
Hydrochloric acid 40ml
1000ml distilled water
B liquid sodium sulfide 8.6g
1000ml distilled water
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.
<Preparation of physical development nucleus layer coating solution>
50 ml of palladium sulfide sol
20% 2% glutaraldehyde solution
Surfactant 1g
Add water to make a total volume of 2000 ml.

Subsequently, the silver halide emulsion layer having the following composition is 3.0 g / m ^{2 in} terms of silver, and the protective layer containing the amorphous silica matting agent is 1.0 g / m ^{2 in} terms of gelatin. The slide was simultaneously applied onto the physical development nucleus layer. The silver halide emulsion was prepared by a general double jet mixing method for photographic silver halide emulsions. This silver halide emulsion was prepared so that the average grain size was 0.1 μm with 95 mol% of silver chloride and 5 mol% of silver bromide.

  The optical image recording material thus obtained is brought into close contact with a transmission original having a line width of 25 microns and a line interval of 300 microns through a resin filter that cuts light of 400 nm or less with a contact printer using a mercury lamp as a light source. After exposure, it was immersed in the following alkaline solution (silver complex diffusion transfer developer) at 25 ° C. for 40 seconds, and then the silver halide emulsion layer, the protective layer and the antihalation layer on the back surface were washed with warm water. Removed to form a conductive silver lattice pattern.

<Alkaline solution>
Sodium hydroxide 20g
Hydroquinone 20g
1-phenyl-3-pyrazolidone 2g
Sodium sulfite 30g
10g monomethylethanolamine
Total volume 1000ml with water
Adjust to pH = 13.

The conductive silver lattice pattern thus obtained was plated using the following copper sulfate plating solution so that the copper thickness was 4 microns.
<Copper sulfate plating solution>
Copper sulfate pentahydrate 220g
60g of sulfuric acid
1N hydrochloric acid 1.4ml
Total volume 1000ml with water
The plated sheet was subsequently immersed in the following enzyme solution at 40 ° C. for 5 minutes, washed with water and dried. The pH of the enzyme solution was 7.0.
<Enzyme solution>
900ml water
7.4 g of 85% orthophosphoric acid
20g triethanolamine
Proteolytic enzyme * 2g
Total volume 1000ml with water
*) Bacterial proteinase: Biolase AL15, manufactured by Nagase Sangyo Co., Ltd.

  By sticking the lead film to both sides of the edge of the sheet treated with the enzyme solution and gently drawing the two lead films, a self-supporting copper mesh with a thickness of 4 microns, a line width of 25 microns, and a line spacing of 300 microns can be obtained. I was able to.

  A silver circuit pattern having a line width / line interval of 50 microns obtained by the same method as in Example 1 was obtained using Meltex Co., Ltd., high-speed electroless copper plating solution for thickening, and Melplate CU-5100. A circuit pattern of about 1 micron was obtained. The sheet was treated with an enzyme solution in the same manner as in Example 1, washed with water and dried, and the circuit pattern side of this sheet was aligned with a semi-cured insulating sheet made of glass epoxy, and heated and pressed to provide a sheet support. The circuit pattern transferred onto the insulating sheet was obtained by gently peeling the film.

A meandering circuit pattern having a line width of 60 microns was obtained by the same method as in Example 1, and then nickel nickel was patterned by electrolytic nickel plating in the following nickel plating bath to obtain a nickel circuit pattern having a thickness of 5 microns. This sheet was treated with an enzyme solution, washed with water and dried in the same manner as in Example 1 to obtain a transfer sheet. The sheet was brought into close contact with soda lime glass previously coated with polyvinyl butyral, subjected to hot pressing, and then the support was gently peeled to obtain a circuit pattern integrated with the glass. This pattern can be used as an anti-fogging heater or a sensor that prevents destructive intrusion from windows.
<Nickel plating solution>
Nickel sulfate 300g
Nickel chloride 50g
40g boric acid
Total volume 1000ml with water

  As an application example of the present invention, in the case of a self-supporting metal mesh, in addition to the electromagnetic wave shielding application, a precision sieve, a screen printing mesh, and the like can be given. In addition to active element applications such as printed circuit boards and heaters, transfer sheet applications include passive element applications such as IC cards and antennas on car window glass.

Claims (2)

  A silver fine wire lattice image formed by silver halide diffusion transfer method is plated with a metal on a support having a protein-containing undercoat layer, and a solution containing a proteolytic enzyme is allowed to act thereon. A self-supporting fine metal mesh obtained by peeling an image from a support.   On a support having a protein-containing undercoat layer, a fine silver wiring pattern formed by silver halide diffusion transfer method is plated with a metal, and a solution containing a proteolytic enzyme is allowed to act thereon, so that the plated metal fine wiring A fine wiring pattern transfer sheet capable of transferring a pattern to another support using an adhesive.