JP2008060118A - Electromagnetic wave shielding film for plasma display and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing an inexpensive electromagnetic wave shielding layer having good quality by applying a silver halide photosensitive material technique, an ink jet technique, and a printing technique. <P>SOLUTION: In the manufacturing method of the electromagnetic wave shielding film for applying exposure and development processing to a photosensitive material having a photosensitive silver salt applied thereon to form a metal silver pattern, a light-shielding ink is applied to the photosensitive material to manufacture a light-shielding ink pattern, and the pattern is exposed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing an electromagnetic wave shielding film for use on the front surface of a plasma display (hereinafter sometimes abbreviated as PDP), which can improve the quality and contribute to the production cost reduction, and also relates to the electromagnetic wave shielding film.

  A plasma display panel (hereinafter referred to as “PDP”) that is light and thin, has high brightness, and provides a large screen is already well known. A PDP is a dielectric layer formed on the inner surface of a front glass substrate by forming a large number of cells in the gap between a front glass substrate and a rear glass substrate (hereinafter referred to as a tube) arranged at intervals and enclosing xenon gas in the tube. In addition, a surface discharge is generated on the surface of the protective layer to excite xenon gas molecules, and ultraviolet rays are generated to emit light from the phosphor in the cell. In this type of PDP in which xenon gas is sealed in a tube, near infrared rays and electromagnetic waves are also generated together with ultraviolet rays generated to cause the phosphor to emit light, and a part thereof is emitted outside the tube. Therefore, a filter having near-infrared cut (absorption) performance, electromagnetic wave shielding performance, scratch prevention performance, antireflection performance, and the like has been attached to the front surface of the conventional PDP (Patent Document 1). In this filter, a silver vapor deposition film is generally formed as an electromagnetic wave shielding layer on a polyester film as a base material, and a near infrared absorption layer is formed by coating a near infrared absorber on the silver vapor deposition film. Usually called a functional film.

As an electromagnetic wave shielding material, in addition to a metal vapor deposition film, a conductive metal pattern, for example, a (linear) antenna element having a frequency selectivity (Patent Document 2), The thing (patent documents 3, 4) etc. which consist of a metal mesh with a high aperture ratio are also proposed.
JP 2000-231338 A JP-A-10-169039 JP 2003-46293 A JP 2004-221565 A

  In the prior art, the production of an electromagnetic wave shielding layer using a silver deposited film or the like has been performed using a large and expensive facility. An object of the present invention is to provide a method for producing an electromagnetic wave shielding layer that is good in quality and inexpensive by applying silver halide photosensitive material technology, ink jet technology, or printing technology. It is to provide an inexpensive electromagnetic wave shielding film.

  The above object of the present invention is achieved by the following means.

  1. In a method for producing an electromagnetic wave shielding film in which a photosensitive silver salt-coated photosensitive material is exposed and developed to form a metallic silver pattern, a light-shielding ink pattern is produced by applying a light-shielding ink to the photosensitive material. And then exposing the film to an electromagnetic wave shielding film.

  2. 2. The method for producing an electromagnetic wave shielding film as described in 1 above, wherein the light-shielding ink is applied by an inkjet coating method.

  3. 2. The method for producing an electromagnetic wave shielding film according to 1 above, wherein the light shielding ink is applied by an offset printing method.

  4). The exposure is a discontinuous whole surface exposure for a region having a light-shielding ink pattern of a predetermined area, or a whole surface exposure onto a photosensitive material web having a light-shielding ink pattern that is continuously conveyed. The manufacturing method of the electromagnetic wave shielding film of any one of said 1-3.

  5. 5. The method for producing an electromagnetic wave shielding film according to any one of 1 to 4, wherein the developing treatment is to remove at least a part of the light-shielding ink pattern.

  6). The electromagnetic wave shielding film manufactured by the manufacturing method of any one of said 1-5.

  By this invention, quality improves and the electromagnetic wave shielding film used for the front surface of the plasma display which can contribute to manufacturing cost reduction, and the manufacturing method of this electromagnetic wave shielding film are obtained.

The best mode for carrying out the present invention will be described below.
In the present invention, the electromagnetic wave shielding material is composed of a conductive metal pattern. For example, an antenna element having frequency selectivity (linear) antenna elements arranged at a constant interval (Patent Document 2), or an aperture ratio. Including a high metal mesh pattern (Patent Documents 3 and 4).

  First, a (linear) antenna element having wave number selectivity will be described.

  When a conductor piece is in the air, when a radio wave is incident on this surface, in the linear antenna element, for example, the end is opened, and the length (electric length) of one side extending from the center is shielded. When the electromagnetic wave is made to resonate with the wavelength to be shielded as a quarter wavelength (1/2 wavelength in a single shape) of the radio wave, the electromagnetic wave can be reflected, scattered and attenuated.

  Moreover, what is necessary is just to make it the same as the wavelength of the electromagnetic wave which is going to shield perimeter (electric length), when it is set as the closed annular | circular shape instead of an edge part open shape.

  Considering the electromagnetic field reflection equivalent area (scattering aperture area) or the electromagnetic field reflection equivalent volume (scattering aperture volume) of such a linear antenna element, it is planar or three-dimensional on a non-conductive material in space. By arranging them at predetermined intervals (antenna element pattern), it is possible to attenuate and shield the electromagnetic wave having the resonated frequency. If the thickness of the conducting wire of the linear antenna element is made thin so as not to obstruct the field of view, the conducting wire portion does not cover the entire surface, so that translucency and visibility are not impaired.

  FIG. 1 shows some examples of radio wave reflecting surfaces having antenna element patterns.

  Small linear antenna elements patterned in this way can be shielded from specific frequencies by specifying their length, and as a result, electromagnetic waves of other wavelengths are allowed to pass through. Only specific radio waves can be shielded without shielding the information that needs to be collected.

  In addition, the conductive metal mesh pattern having a large aperture ratio forms a shielding material having translucency and electromagnetic wave shielding properties (no wavelength selectivity). For example, there is a square lattice pattern as shown in FIG. A continuous mesh pattern having both translucency and conductivity, for example, having a line width of 10 μm and a pitch of 200 μm.

  The present invention uses a silver halide photosensitive material (thus using silver as a metal material), for example, on a continuous web made of a non-conductive film substrate such as a polyimide film, a polyester film, or a polyethylene film. The present invention relates to a method for producing an electromagnetic wave shielding film for continuously and efficiently producing a plurality of antenna element patterns or mesh patterns corresponding to different electromagnetic wave shielding conditions such as frequency selectivity and transmittance.

  The conceptual diagram of the whole manufacturing process of the electromagnetic wave shielding film of this invention is shown in FIG.

  The first step is a step in which a photosensitive silver salt is first applied to a film substrate fed from an original winding roll to form a photosensitive material. The formed photosensitive material web is continuously dried and then passed through a light shielding material coating process in which a light shielding material is coated on the photosensitive material. The light shielding material is applied in accordance with a required pattern using a light shielding ink by, for example, an ink jet method. This masks the region other than the region of the photosensitive material surface on which the conductive metal pattern is to be formed.

  When the light-shielding ink is applied in a pattern, the photosensitive material web is then in the exposure process. The exposure process is a process in which a conductive pattern is recorded on a continuous web. In the exposure process, the photosensitive material is continuously exposed, and light shielding ink is applied to the area to be the opening. The region where the conductive metal silver pattern is to be formed is exposed.

  The development step is a step of converting the pattern recorded on the web into a metallic silver pattern. The photosensitive material is continuously developed by the development step, and the light-shielding ink is removed, so that exposure is performed. A conductive metal pattern is formed by the metallic silver formed on the part.

  By forming the conductive metal pattern, for example, a mesh pattern including a conductive metal silver portion and an opening is obtained. Moreover, if an antenna element is formed, a frequency-specific electromagnetic shielding pattern is formed on the film substrate, and the electromagnetic shielding film of the present invention is produced.

  As shown in FIG. 2, in the manufacturing process of the electromagnetic wave shielding film, it is preferable to provide a conductivity imparting step after the developing step. The conductivity imparting step is a step of further enhancing the conductivity of metallic silver formed on the photosensitive material by development, and specifically, the conductivity of metallic silver (pattern) by physical development treatment and / or plating treatment. Is a step of further increasing

  Thereafter, the electromagnetic wave shielding film can be continuously formed in a web shape by providing an additional step such as coating of a filter layer or coating of a reflective layer, for example, to form a PDP front plate. In the formed electromagnetic wave shielding film, for example, an infrared absorption layer, an adhesive layer, and an antireflection layer or the like may be formed on the outermost surface in the additional step.

  Therefore, in the present invention, a light-shielding ink is applied to a photosensitive material coated with a photosensitive silver salt to produce a light-shielding ink pattern, and then exposed, developed, and a conductive metal pattern made of silver is formed on the film. It is a manufacturing method of the electromagnetic wave shielding film formed in this.

  Hereinafter, embodiments of the present invention will be described in more detail.

  In FIG. 3, a light-shielding material is applied to a photosensitive material coated with a photosensitive silver salt according to the present invention to produce a light-shielding ink pattern, which is then exposed and developed to form a conductive metal pattern made of silver with a film. An example of the specific aspect of the formation process of the electromagnetic wave shielding film until it forms above is shown.

  As a support film to be a film base, various transparent materials such as polyester films such as PET (polyethylene terephthalate) and PC (polycarbonate), polycarbonate films, cellulose ester films such as triacetyl cellulose, and PMMA (polymethyl methacrylate). A roll of a resin film (having a thickness of about 25 to 250 μm, for example) can be used.

  These film base materials may have a known hydrophilic undercoat layer for coating a photosensitive silver salt (silver halide emulsion) layer.

  These support films are usually continuously formed in a roll form, and the subbing treatment and the like are continuously performed in a roll form.

  In the present invention, a photosensitive silver salt is continuously applied to a base film, and a metal silver pattern is formed on the base film by exposure and development to produce an electromagnetic wave shielding film.

  In FIG. 3, the film base fed out from the film roll serving as the base is successively subjected to a silver salt coating process, a light shielding material coating process by inkjet, an exposure process, and a development process to form a metallic silver pattern on the base film. It becomes an electromagnetic wave shielding film formed.

  Preferably, after the silver pattern is formed, it is preferable that conductivity is imparted, for example, by plating or further physical development.

  A 1st silver salt application | coating process is a process of apply | coating photosensitive silver salt first on a base film (for example, polyester film), and setting it as a photosensitive material.

(Photosensitive silver salt)
Examples of the photosensitive silver salt used in the present invention include inorganic silver salts such as silver halide and organic silver salts such as silver acetate, but it is preferable to use silver halide having excellent characteristics as an optical sensor.

  In the present invention, silver halide is used in order to function as an optical sensor, but the technology relating to silver halide used in silver salt photographic film, photographic paper, film for printing plate making, emulsion mask for photomask, etc. Can be used as is.

  The halogen element contained in the silver halide may be any of chlorine, bromine, iodine and fluorine, or a combination thereof. For example, silver halide mainly composed of AgCl, AgBr, and AgI is preferably used, and silver halide mainly composed of AgBr is preferably used.

  Here, “silver halide mainly composed of AgBr (silver bromide)” refers to silver halide in which the molar fraction of bromide ions in the silver halide composition is 50% or more. The silver halide grains mainly composed of AgBr may contain iodide ions and chloride ions in addition to bromide ions.

  Since silver halide is in the form of solid grains, from the viewpoint of the quality of the mesh-patterned metallic silver layer formed after exposure and development processing, the average grain size of silver halide is 0.1 to 1000 nm in terms of sphere equivalent diameter. (1 μm) is preferable, 1 nm to 100 nm is more preferable, and 10 nm to 100 nm is even more preferable. Incidentally, the sphere equivalent diameter of silver halide grains is the diameter of grains having the same volume and a spherical shape.

  The shape of the silver halide grains is not particularly limited, and may be various shapes such as a spherical shape, a cubic shape, a flat plate shape (hexagonal flat plate shape, triangular flat plate shape, tetragonal flat plate shape, etc.), octahedron shape, and tetrahedron shape. Can be.

The silver halide may further contain other elements. For example, in a photographic emulsion, it is useful to dope metal ions used for obtaining a high-contrast emulsion. In particular, transition metal ions such as rhodium ions and iridium ions are preferably used because a difference between an exposed portion and an unexposed portion tends to occur clearly when a metallic silver image is generated. Transition metal ions represented by rhodium ions and iridium ions can also be compounds having various ligands. Examples of such a ligand include cyanide ions, halogen ions, thiocyanate ions, nitrosyl ions, water, hydroxide ions, and the like. Specific examples of the compound include K ₃ Rh ₂ Br ₉ and K ₂ IrCl ₆ .

In the present invention, the content of the rhodium compound and / or iridium compound contained in the silver halide is preferably 10 ⁻¹⁰ to 10 ⁻² mol / mol Ag with respect to the number of moles of silver in the silver halide. And more preferably 10 ⁻⁹ to 10 ⁻³ mol / mol Ag.

  In addition, silver halides containing Pd (II) ions and / or Pd metals can also be preferably used. Such silver halide grains can be prepared by adding Pd in the process of forming silver halide grains. It is also preferred that Pd (II) ions be present on the surface of the silver halide by a method such as addition at the time of post-ripening.

  Pd is well known as an electroless plating catalyst, and the inclusion of this Pd increases the speed of physical development and electroless plating, increases the production efficiency of a desired electromagnetic shielding material, and reduces the production cost. Contribute.

In the present invention, the content of Pd ions and / or Pd metal contained in the silver halide is preferably 10 ⁻⁸ to 10 ⁻⁴ mol / mol Ag with respect to the number of moles of silver in the silver halide, More preferably, it is 10 ⁻⁶ to 10 ⁻⁵ mol / mol Ag.

Further, in order to suppress the binding with gelatin and coordinate more efficiently to AgX, it is preferably added as a Pd (SCN) ₂ complex or palladium glycinate.

Examples of the Pd compound include PdCl ₄ and Na ₂ PdCl ₄ .

  The silver halide can be subjected to chemical sensitization performed in a silver halide photographic emulsion in order to further improve the sensitivity as an optical sensor. As chemical sensitization, for example, noble metal sensitization such as gold sensitization, chalcogen sensitization such as sulfur sensitization, reduction sensitization or the like can be used.

  Examples of emulsions that can be used in the present invention include color negatives described in Examples of JP-A-11-305396, JP-A-2000-321698, JP-A-13-281815, and JP-A-2002-72429. A film emulsion, a color reversal film emulsion described in JP-A No. 2002-214731, a color photographic paper emulsion described in JP-A No. 2002-107865, and the like can be suitably used.

<binder>
In the silver salt-containing layer of the present invention, the binder can be used for the purpose of uniformly dispersing the silver salt particles and assisting the adhesion between the silver salt-containing layer and the support. Either a polymer or a water-soluble polymer can be used as a binder, but a water-soluble polymer is preferably used.

  Examples of the binder include gelatin, polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), polysaccharides such as starch, cellulose and derivatives thereof. Gelatin is particularly preferred.

  Content of the binder contained in the silver salt content layer of this invention is not specifically limited, It can determine suitably in the range which can exhibit a dispersibility and adhesiveness. The content of the binder in the silver salt-containing layer is preferably 1/4 to 100 in terms of Ag / binder volume ratio, more preferably 1/3 to 10, and more preferably 1/2 to 2. Further preferred. Most preferably, it is 1 / 1-2. If the silver salt-containing layer contains a binder in an Ag / binder volume ratio of 1/4 or more, the metal particles can easily come into contact with each other in the physical development and / or plating process, and high conductivity can be obtained. Therefore, it is preferable.

  In addition to the photosensitive silver salt, the silver salt-containing layer of the present invention may contain various additives such as an activator and a hardener.

  The solvent used in the silver salt-containing layer of the present invention is not particularly limited. For example, water, organic solvents (for example, alcohols such as methanol, ketones such as acetone, amides such as formamide, dimethyl, etc. Sulfoxides such as sulfoxide, esters such as ethyl acetate, ethers and the like), ionic liquids, and mixed solvents thereof. In order to use a silver halide gelatin emulsion, it is preferable to mainly use water.

  The above silver salt layer may be applied by coating an aqueous coating solution of, for example, a silver halide emulsion containing the above-mentioned components on a base film using various coaters well known in the photographic industry. For example, slide coating, extrusion coating, spray coating, etc. are not particularly limited. In the application step, for example, as shown in FIG. 3, the application film is applied to the base film on the backup roll by the application liquid supplied from the coater head 10 facing the backup roll.

Specific examples of the silver halide emulsion used in the present invention include, for example, a halogen containing fine AgBrI (I = 2 mol%) grains having a spherical equivalent diameter (average grain diameter) of 0.05 μm containing 3 g of gelatin per 38 g of silver. The silver halide emulsion may be coated on an undercoated PET film (100 μm thickness) so that the silver amount is about 5 g / m ² together with a gelatin hardener after gold-sulfur sensitization.

  After the coating, the dried photosensitive material that is passed (omitted) through the drying process is then subjected to a light shielding material coating process (by inkjet). Here, the photosensitive material web continuously conveyed is continuously supplied with the light-shielding ink from the ink-jet head 100 by the ink-jet method, and a pattern of the light-shielding ink is formed on the photosensitive material.

  After coating the photosensitive silver salt layer, it may be a light shielding material coating step without drying, but the photosensitive silver salt layer and the ink layer are mixed together so that the light shielding performance may be insufficient. In this case, whether or not there is such a problem depends on the composition of the photosensitive silver salt layer, the ink composition, etc., and therefore judgment is carefully made.

  The light-shielding ink is applied by an ink jet (IJ) method to a portion other than a region where a silver pattern necessary as an electromagnetic wave shielding layer is formed. For example, in the case of a mesh pattern, light-shielding ink is applied to a portion that becomes an opening after development.

  Thereafter, the entire surface is exposed without a mask, and development processing is performed to fix silver particles and peel (dissolve) the ink to form a necessary metallic silver pattern.

  In FIG. 4, a light-shielding ink pattern is formed on the photosensitive material web (FIG. 4A) by inkjet (IJ) coating (FIG. 4B), and further, a metal silver pattern is formed by exposure and development processes. As shown in FIG. 4 (c). The mesh pattern formed in the figure is, for example, a developed silver mesh image having a line width of 10 μm and a line pitch of 200 μm.

(Light-shielding ink)
In the present invention, the light-shielding ink is preferably water-soluble, and the light-shielding ink is printed such that the average transmittance at a wavelength of 370 to 780 nm of the ink layer is 30% or less when applied (printed). . As the light-shielding ink, a water-based ink in which a dispersant and a light-shielding pigment are contained in a water-soluble polymer can be used.

  Examples of the light-shielding ink layer pigment include carbon black, aluminum powder (Pigment Metal 1), bronze powder, copper powder (Pigment Metal 2), tin powder (Pigment Metal 5), lead powder (Pigment Metal 4), and zinc. Metal powder such as powder metal (Pigment Metal 6) can also be used.

  The water-soluble polymer constituting the ink includes natural water-soluble polymer compounds such as alginic acid, dextran, dextrin, guar gum, gum arabic, pectin, casein, agar, and xanthan gum, and synthetic polymer compounds such as polyvinyl alcohol and polyvinyl pyrrolidone. There may be.

  Further, the light-shielding pigment is not necessarily required to be black as long as it has a property of absorbing the exposure wavelength, but carbon black is preferable because it absorbs the entire visible light.

  For example, a small amount of Olfin e1010 (manufactured by Nisshin Chemical Co., Ltd.) in which about 3.5 to 5% by mass of carbon black as a light-shielding pigment is dispersed in an aqueous solution of about 3.5% by mass polyvinyl alcohol as a water-soluble polymer ) Used as a light-shielding ink and sprayed from the inkjet head 100 and applied.

  The ink jet head may be an on-demand system or a continuous system. In addition, as a discharge method, an electro-mechanical conversion method (for example, a single cavity type, a double cavity type, a bender type, a piston type, a shear mode type, a shared wall type, etc.), an electro-thermal conversion method (for example, thermal ink jet) Any ejection method such as a mold, a bubble jet (registered trademark) mold, or the like may be used.

  Among them, recording is performed on a photosensitive material with a piezo ink jet recording head having a nozzle diameter of 30 μm or less, and recording is performed at a printing speed of 20 ppm or more using a piezo ink jet recording head having a nozzle diameter of 30 μm or less. It is preferable to record an image on the material.

  As a printing method of the inkjet printer, printing may be performed using a line head type recording head with respect to a shuttle head type recording head.

  As a process for applying the light-shielding ink, an offset printing method may be mentioned as one of preferable methods.

FIG. 5 schematically shows an example of a process using offset printing.
According to this method, the ink is once transferred to the blanket 52 from the printing original plate 51 to which the ink corresponding to the light-shielding pattern is transferred from the ink supply roll 50, and then the blanket is placed on the photosensitive material that is transported on the pressure copper 53. Thus, printing is performed by transfer from the ink, and light-shielding ink can be continuously printed on the photosensitive material.

(Light-shielding ink)
In the present invention, the light-shielding ink is preferably water-soluble, and the light-shielding ink is printed so that the average transmittance at a wavelength of 370 to 780 nm is 30% or less when applied (printed). The light-shielding ink comprises the aforementioned hydrophilic polymer for ink and a light-shielding pigment.

  In addition to carbon black, the light-shielding pigment includes aluminum powder (Pigment Metal 1), bronze powder, copper powder (Pigment Metal 2), tin powder (Pigment Metal 5), lead powder (Pigment Metal 4), and zinc powder (Pigment). Metal powder such as Metal 6) can also be used.

  As the hydrophilic polymer constituting the ink, natural water-soluble polymer compounds such as alginic acid, dextran, dextrin, guar gum, gum arabic, pectin, casein, agar, and xanthan gum are preferable, but synthetic polymer compounds may also be used. Like the ink, an activator or the like is added to form a paste.

  The next exposure step is a step in which the photosensitive material on which the light-shielding ink pattern is formed is exposed to at least a region where the light-shielding ink pattern is formed in the exposure zone. The pattern portion may be exposed to the entire surface from the light-shielding ink pattern side, and can be continuously performed along with the conveyance of the photosensitive material web. The exposure intensity is adjusted according to the sensitivity of the photosensitive material and the conveying speed of the photosensitive material so that the photosensitive material web can be exposed uniformly and continuously with a sufficient exposure amount determined by the sensitivity of the photosensitive material.

  Further, a method of intermittently exposing only a region where the light-shielding ink pattern is formed, that is, discontinuous whole surface exposure for a predetermined area having the light-shielding ink pattern may be used.

  The exposure is not necessarily white, and a light source that matches the spectral sensitivity of the photosensitive material may be used.

  Various light sources such as a tungsten lamp, a fluorescent lamp, and a mercury lamp are used as the light source. A surface light source may be used.

  When producing an electromagnetic wave shielding film with a photosensitive material using a photosensitive silver salt, patterning by exposure is conventionally performed using a masking member, etc., but in the roll-to-roll manufacturing method, the masking member is exposed one by one. According to the present invention, this is easy and preferable because of uniform front exposure.

  The method using a masking member has to reduce the production speed in roll-to-roll, which is slightly inferior, and the production cost is also somewhat bad. The method of forming a light-shielding ink pattern by the ink jet method according to the present invention is advantageous from the viewpoint of manufacturing cost because the light-shielding pattern can be continuously formed and the development process can be continuously performed. In addition, even in the case where the light-shielding pattern is formed by the (offset) printing method, the offset printing is highly efficient, so that the pattern can be formed with the efficiency not much different from the ink jet method and the efficiency is high.

  On the other hand, unlike the present application, it is considered that even if the exposure is continuously performed with a laser, a speed that is not so different can be obtained, but the continuous scanning exposure by the laser has a large cost burden such as control of the exposure apparatus or maintenance, It costs as a manufacturing cost.

  Subsequent to the exposure process, a development process (development process) is performed to perform silver development, fixing of the silver image, and removal of the light-shielding ink, thereby forming a metallic silver pattern and forming an electromagnetic wave shielding pattern.

(Development processing)
In the present invention, after the silver salt-containing layer is exposed, development processing is further performed. The development processing can be performed by a normal development processing technique used for silver salt photographic film, photographic paper, printing plate-making film, photomask emulsion mask, and the like. The developer is not particularly limited, but a PQ developer, MQ developer, MAA developer, etc. can also be used. For example, CN-16, CR-56, CP45X, FD-3, Papitol manufactured by Fuji Film Co., Ltd. A developer such as C-41, E-6, RA-4, D-19, D-72 manufactured by KODAK, or a developer included in the kit, or a lith developer such as D-85 is used. be able to.

  In the present invention, by performing the above exposure and development treatment, a metallic silver portion, preferably a patterned metallic silver portion is formed, and a light transmissive portion described later is formed.

  The development processing in the present invention can include a fixing processing performed for the purpose of removing and stabilizing the silver salt in the unexposed portion. For the fixing process in the present invention, a fixing process technique used for a silver salt photographic film, photographic paper, a printing plate-making film, a photomask emulsion mask or the like can be used.

  The developer used in the development process can contain an image quality improver for the purpose of improving the image quality. Examples of the image quality improver include nitrogen-containing heterocyclic compounds such as benzotriazole. In addition, it is also preferable to use polyethylene glycol, particularly when a lith developer is used.

  The mass of the metallic silver contained in the exposed portion after the development treatment is preferably a content of 50% by mass or more, and 80% by mass or more with respect to the mass of silver contained in the exposed portion before exposure. More preferably. If the mass of silver contained in the exposed portion is 50% by mass or more based on the mass of silver contained in the exposed portion before exposure, it is preferable because high conductivity can be obtained.

  The gradation after development processing in the present invention is not particularly limited, but is preferably more than 4.0. When the gradation after the development processing exceeds 4.0, the conductivity of the conductive metal portion can be increased while keeping the transparency of the light transmissive portion high. Examples of means for setting the gradation to 4.0 or higher include the aforementioned doping of rhodium ions and iridium ions.

  Further, the silver halide that has not been converted into a metal image is removed by a photographic fixing process included in the development process.

  For example, the developer is developed with a CDH-100 developer at 25 ° C. (manufactured by Konica Minolta) for 60 seconds, then treated with a CFL871 fixer (manufactured by Konica Minolta) for 3 minutes, and then washed with warm pure water at 40 ° C. for 5 minutes. Development processing can be performed.

  Further, during these development processing steps, the water-soluble light-shielding ink is removed by dissolution, peeling or the like by a developer, a fixing solution, water washing or the like. It is preferable that water-soluble ink exudes into the developer and most of the ink is removed. However, it is not necessary to remove all of the ink in the developer, and at least a part of the ink is removed in the developer. It is preferable to remove all during the development process.

  After these development treatments, the film web is further dried to obtain the electromagnetic wave shielding film according to the present invention having a developed silver pattern on the substrate film.

  Through the above steps, the silver salt coating, masking, exposure, and development processing steps can be performed by continuous conveyance. That is, it becomes possible to produce roll-to-roll of electromagnetic shielding films.

  In the method for producing an electromagnetic wave shielding film of the present invention, in a preferred embodiment, a conductivity imparting step for further enhancing the conductivity is further provided on the metallic silver after the development step. Specifically, the conductivity imparting step is physical development and / or plating, whereby the conductive metal particles are supported on the metal silver portion.

(Physical development and plating)
In the present invention, for the purpose of imparting conductivity to the metal silver portion formed by the exposure and development processing, physical development and / or plating treatment for supporting the conductive metal particles on the metal silver portion is performed. In the present invention, it is possible to support the conductive metal particles on the metallic part only by physical development or plating treatment, but it is also possible to support the conductive metal particles on the metallic silver part by combining physical development and plating treatment. it can.

  In the present invention, “physical development” means that metal ions such as silver ions are reduced with a reducing agent on metal or metal compound nuclei to deposit metal particles. This physical phenomenon is used for instant B & W film, instant slide film, printing plate manufacturing, and the like, and the technology can be used in the present invention.

  Further, the physical development may be performed simultaneously with the development processing after exposure or separately after the development processing.

  In the present invention, the plating treatment can be performed using electroless plating (chemical reduction plating or displacement plating), electrolytic plating, or both electroless plating and electrolytic plating. For the electroless plating in the present invention, a known electroless plating technique can be used. For example, an electroless plating technique used for a printed wiring board can be used, and the electroless plating is an electroless copper plating. Preferably there is.

  Chemical species contained in the electroless copper plating solution include copper sulfate and copper chloride, formalin and glyoxylic acid as the reducing agent, EDTA and triethanolamine as the copper ligand, and other bath stabilization and plating film Examples of the additive for improving the smoothness include polyethylene glycol, yellow blood salt, and bipyridine. Examples of the electrolytic copper plating bath include a copper sulfate bath and a copper pyrophosphate bath.

  The plating speed at the time of plating in the present invention can be performed under moderate conditions, and high-speed plating of 5 μm / hr or more is also possible. In the plating treatment, various additives such as a ligand such as EDTA can be used from the viewpoint of improving the stability of the plating solution.

(Oxidation treatment)
In the present invention, oxidation treatment is preferably performed on the metallic silver portion after the development treatment and the conductive metal portion formed after the physical development and / or plating treatment. By performing the oxidation treatment, for example, when a metal is slightly deposited on the light transmissive portion, the metal can be removed and the light transmissive portion can be made almost 100% transparent.

  Examples of the oxidation treatment include known methods using various oxidizing agents such as Fe (III) ion treatment. The oxidation treatment can be performed after exposure and development processing of the silver salt-containing layer, or after physical development or plating treatment, and may be performed after development processing and after physical development or plating treatment.

  In the present invention, the metallic silver portion after the exposure and development treatment can be further treated with a solution containing Pd. Pd may be a divalent palladium ion or metallic palladium. This treatment can accelerate electroless plating or physical development speed.

  For example, as a plating solution, copper sulfate 0.06 mol / L, formalin 0.22 mol / L, triethanolamine 0.12 mol / L, and polyethylene glycol 100 ppm, yellow blood salt 50 ppm, α, α′-bipyridine 20 ppm As an example, an electroless Cu plating solution having a pH of 12.5 and containing, for example, after performing an electroless copper plating process at 45 ° C. using the plating solution, about 10 ppm of Fe ( III) Oxidation is performed with an aqueous solution containing ions.

  As the conductive metal particles supported on the metal part, in addition to the above-described silver (in the case of physical development), copper, aluminum, nickel, iron, gold, cobalt, tin, stainless steel, tungsten, chromium, titanium, palladium, platinum And particles of metals such as manganese, zinc, rhodium, or alloys obtained by combining these metals. From the viewpoint of conductivity, cost, etc., the conductive metal particles are preferably copper, aluminum or nickel particles. Moreover, when providing magnetic field shielding properties, it is preferable to use paramagnetic metal particles as the conductive metal particles.

  In the conductive metal part, from the viewpoint of increasing the contrast and preventing the conductive metal part from being oxidized and discolored over time, the conductive metal part contained in the conductive metal part is a copper particle. It is preferable.

  The conductive metal part preferably contains 50% by mass or more, and more preferably 60% by mass or more of silver with respect to the total mass of the metal contained in the conductive metal part. When silver is contained in an amount of 50% by mass or more, the time required for physical development and / or plating can be shortened, productivity can be improved, and cost can be reduced.

  Furthermore, when copper and palladium are used as the conductive metal particles forming the conductive metal part, the total mass of silver, copper and palladium is 80% by mass or more based on the total mass of the metal contained in the conductive metal part. It is preferable that it is 90 mass% or more.

Since the conductive metal portion in the present invention carries conductive metal particles, good conductivity can be obtained. For this reason, the surface resistance value of the translucent electromagnetic wave shielding film (conductive metal portion) of the present invention is preferably 10 3 Ω / sq or less, more preferably 2.5 Ω / sq or less,
More preferably, it is 1.5Ω / sq or less, and most preferably 0.1Ω / sq or less.

  When the conductive metal portion of the present invention is used as a light-transmitting electromagnetic wave shielding material, a triangle such as an equilateral triangle, an isosceles triangle, a right triangle, a square, a rectangle, a rhombus, a parallelogram, a quadrangle such as a trapezoid, More preferably, it is a mesh shape composed of geometric figures combining (positive) hexagons, (positive) n-gons such as (positive) octagons, circles, ellipses, and stars. From the viewpoint of EMI shielding properties, the triangular shape is the most effective, but from the viewpoint of visible light transmittance, if the same line width is used, the larger the (positive) n-gonal n number, the higher the aperture ratio and the visible light transmittance. This is advantageous because it becomes larger.

  In the use of the translucent electromagnetic wave shielding material, the conductive metal portion preferably has a line width of 20 μm or less and a line interval of 50 μm or more. The conductive metal portion may have a portion whose line width is wider than 20 μm for the purpose of ground connection or the like. Further, from the viewpoint of making the image inconspicuous, the line width of the conductive metal part is preferably less than 18 μm, more preferably less than 15 μm, further preferably less than 14 μm, and less than 10 μm. Is most preferred.

  The conductive metal portion in the present invention has an aperture ratio of preferably 85% or more, more preferably 90% or more, and most preferably 95% or more from the viewpoint of visible light transmittance. The aperture ratio is the ratio of the portion without fine lines forming the mesh to the whole. For example, the aperture ratio of a square lattice mesh having a line width of 10 μm and a pitch of 200 μm is 90%.

(Light transmissive part)
The “light transmitting part” in the present invention means a part having transparency other than the conductive metal part in the light transmitting electromagnetic wave shielding film. As described above, the transmittance of the light-transmitting portion is 90% or more, preferably 95, as shown by the minimum transmittance in the wavelength range of 380 to 780 nm excluding the contribution of light absorption and reflection of the support. % Or more, more preferably 97% or more, even more preferably 98% or more, and most preferably 99% or more.

(Layer structure of electromagnetic shielding film)
The thickness of the support in the electromagnetic wave shielding film of the present invention is preferably 5 to 200 μm, and more preferably 30 to 150 μm. If it is the range of 5-200 micrometers, the transmittance | permeability of a desired visible light will be obtained and handling will also be easy.

  The thickness of the metallic silver portion provided on the support before physical development and / or plating can be appropriately determined according to the coating thickness of the photosensitive silver salt layer coating applied on the support. The thickness of the metallic silver part is preferably 30 μm or less, more preferably 20 μm or less, further preferably 0.01 to 9 μm, and most preferably 0.05 to 5 μm. Moreover, it is preferable that a metal silver part is pattern shape.

  The thickness of the conductive metal portion is preferable for use as an electromagnetic shielding material for a display because the viewing angle of the display is increased as the thickness is reduced. Furthermore, as a use of the conductive wiring material, a thin film is required because of a demand for high density. From such a viewpoint, the thickness of the layer made of the conductive metal carried on the conductive metal part is preferably less than 9 μm, more preferably 0.1 μm or more and less than 5 μm, and more preferably 0.1 μm or more. More preferably, it is less than 3 μm.

  In the method for producing an electromagnetic wave shielding film of the present invention, an additional step may be provided after the physical development treatment and / or plating treatment, and a near-infrared absorbing layer, an adhesive layer, an antireflection layer, and the like may be provided.

  These layers can also be provided by applying a coating solution for forming these layers on the web in succession following development, plating and the like.

  For coating, the same coater as that used in the photosensitive material can be used. Also, a method such as ink jet or printing may be used.

  The near-infrared shielding layer is, for example, various organic or complex compounds having absorption in the range of 850 to 1250 nm in order to obtain the ability to sufficiently absorb near infrared rays in a wide wavelength range of near infrared such as 850 to 1250 nm. Examples thereof include a coating layer having a thickness of 0.5 to 30 μm in which a system dye is dissolved in a resin (for example, a polyester resin, an acrylic resin, an ethylene-vinyl acetate copolymer resin, or the like).

  Further, an adhesive layer can be further formed on the outermost surface for use as a front plate for PDP. As the pressure-sensitive adhesive (pressure sensitive adhesive), a thermoplastic elastomer such as acrylic, SBS, SEBS or the like is preferably used. To these pressure-sensitive adhesives, tackifiers, ultraviolet absorbers, colored pigments, colored dyes, anti-aging agents, adhesion-imparting agents, and the like can be appropriately added. The thickness of the pressure-sensitive adhesive layer 8 is preferably about 10 to 1000 μm. Further, an appropriate release paper (film) can be attached to the adhesive layer 8.

Moreover, it is preferable that an antireflection layer exists in the outermost surface, and in the case of the electromagnetic wave shielding film of this invention, it is preferable to coat on the opposite side to the side which has a conductive silver pattern.
(1) A single layer of a transparent film having a lower refractive index than the constituent material of the panel to which the electromagnetic wave shielding light-transmitting laminated film is attached. (2) Total of one high refractive index transparent film and one low refractive index transparent film. Laminated in two layers (3) Laminated high-refractive-index transparent film and low-refractive-index transparent film alternately in total 4 layers (4) Medium refractive index transparent film / High refractive index transparent film / Low refractive index 1 layer in the order of the transparent film, laminated in a total of 3 layers (5) 3 layers alternately in the order of high refractive index transparent film / low refractive index transparent film, 6 layers in total, etc. Can be mentioned.

  For example, an antireflection layer in which, for example, a low refractive index silicon oxide layer is coated on a hard coat layer formed from a hard coat composition containing dipentaerythritol hexaacrylate or the like can be mentioned.

  In FIG. 6, the manufacturing process of the electromagnetic wave shielding film which added the formation process of the reflection prevention layer in addition to the said electroconductivity provision process is shown. Similarly, you may add a near-infrared shielding layer, an adhesion layer, release paper bonding, etc. after this as an addition process (it may be continuous or discontinuous).

  FIG. 7 schematically shows a cross-sectional view of an example of the electromagnetic wave shielding film produced by the production method of the present invention. A metallic silver pattern layer 2, a near-infrared shielding layer 3, an adhesive layer 4, and a release paper 5 are bonded onto the base film 1, and an antireflection layer 6 is formed on the back surface.

  The antireflection layer, near-infrared shielding layer, etc. are separately coated on a film substrate, and the antireflection film or filter is bonded to the electromagnetic wave shielding film according to the present invention as a multilayer film. For example, you may use for the front plate for PDP. In this case, on the transparent base film (thickness is about 25 to 250 μm, for example), an antireflection layer comprising the following single layer film (1), a laminated film of a high refractive index transparent film and a low refractive index transparent film, What is necessary is just to apply and use the layer containing the material which has the said near-infrared absorptivity. Also about these base film, a transparent film is preferable and resin films, such as PET (polyethylene terephthalate), PC (polycarbonate), a cellulose ester (triacetylcellulose), PMMA (polymethylmethacrylate), are mentioned.

  Moreover, when laminating a film, the adhesive resin is preferably a transparent and elastic material, for example, one that is usually used as an adhesive for laminated glass. Specifically, the thickness of an ethylene-vinyl acetate copolymer, an ethylene-methyl acrylate copolymer, or the like is preferably about 10 to 1000 μm, for example.

  As mentioned above, although the manufacturing method of the electromagnetic wave shielding film concerning this invention required for a plasma display panel (PDP) was demonstrated, the light-shielding ink was apply | coated to the part other than a pattern by inkjet after apply | coating silver salt on the film entirely. By performing the development process, an electromagnetic wave shielding film having a developed silver pattern on the base film can be produced on a roll-to-roll basis. Using this electromagnetic wave shielding film, an electromagnetic wave shielding front plate for PDP can be easily produced. Is obtained. Although only the production of the electromagnetic wave shielding mesh pattern has been described, the frequency selective electromagnetic wave shielding film can be similarly obtained by printing the antenna element pattern with the light shielding ink.

It is a figure which shows some examples of the electromagnetic wave reflective surface which has an antenna element pattern. It is a conceptual diagram of the whole manufacturing process of the electromagnetic wave shielding film of this invention. It is a figure which shows an example of the specific aspect of the formation process of the electromagnetic wave shielding film of this invention. It is a schematic diagram showing the formation of a light-shielding ink pattern by IJ, and the formation of a metal silver pattern by exposure and development. It is a figure which shows typically an example of the process using offset printing. It is a conceptual diagram of the whole manufacturing process of the electromagnetic wave shielding film which added the antireflection layer formation process. It is a schematic cross section which shows an example of the electromagnetic wave shielding film of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base film 2 Metal silver pattern layer 3 Near-infrared shielding layer 4 Adhesive layer 5 Release paper 6 Antireflection layer 10 Coater head 100 Inkjet head

Claims (6)

In a method for producing an electromagnetic wave shielding film in which a photosensitive silver salt-coated photosensitive material is exposed and developed to form a metallic silver pattern, a light-shielding ink pattern is produced by applying a light-shielding ink to the photosensitive material. And then exposing the film to an electromagnetic wave shielding film. The method for producing an electromagnetic wave shielding film according to claim 1, wherein the light-shielding ink is applied by an ink jet coating method. The method for producing an electromagnetic wave shielding film according to claim 1, wherein the light-shielding ink is applied by an offset printing method. The exposure is a discontinuous whole surface exposure for a region having a light-shielding ink pattern of a predetermined area, or a whole surface exposure onto a photosensitive material web having a light-shielding ink pattern that is continuously conveyed. The manufacturing method of the electromagnetic wave shielding film of any one of Claims 1-3. The method for producing an electromagnetic wave shielding film according to any one of claims 1 to 4, wherein the developing treatment removes at least a part of the light-shielding ink pattern. The electromagnetic wave shielding film manufactured by the manufacturing method of any one of Claims 1-5.

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