JP2007242915A - Light transmissive electromagnetic wave shielding material, manufacturing method thereof, and filter for display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a light transmissive electromagnetic wave shielding material having improved manufacturing efficiency. <P>SOLUTION: The manufacturing method of the light transmissive electromagnetic wave shielding material includes: a process for coating a transparent substrate 11 with a mixture or a reaction product of a silane coupling agent and an azole-based compound, and a pretreatment agent for electroless plating containing a noble metal compound for drying to form a pretreatment layer 12 on the transparent substrate 11; a process for forming a dot-like plating protective layer 13 on the pretreatment layer 12; and a process for forming a mesh-like metal conductive layer 14 on the pretreatment layer 12 exposed without forming the plating protective layer 13 by electroless plating. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is a method for producing a light-transmitting electromagnetic wave shielding material useful as a front sheet filter of a plasma display panel (PDP), a sticking sheet or the like that can be used for a window of a building such as a hospital that requires an electromagnetic wave shield, The present invention relates to a light-transmitting electromagnetic wave shielding material manufactured by a manufacturing method and a display panel including the light-transmitting electromagnetic wave shielding material.

  In recent years, with the spread of OA equipment, communication equipment, etc., there is a concern about the influence on the human body caused by electromagnetic waves generated from these equipment. In addition, electromagnetic waves from a mobile phone or the like may cause malfunction of precision equipment, and electromagnetic waves are regarded as a problem.

  Therefore, a light-transmitting electromagnetic wave shielding material having an electromagnetic wave shielding property and a light transmitting property has been developed and put into practical use as a front filter for a PDP of an OA device. Such a light-transmitting electromagnetic wave shielding material is also used as a window material for installation of precision equipment such as hospitals and laboratories in order to protect precision equipment from electromagnetic waves.

  In this light-transmitting electromagnetic wave shielding material, it is necessary to satisfy both the light transmitting property and the electromagnetic wave shielding property. Therefore, for example, a conductive layer having a fine mesh structure is used as the light-transmitting electromagnetic wave shielding material. Electromagnetic waves are shielded by the conductive mesh portion, and light transmission is ensured by the opening.

  The light-transmitting electromagnetic wave shielding layer is manufactured by various methods. As a preferable manufacturing method, for example, there is a method as shown in FIG. First, a mesh negative pattern is printed on the transparent substrate 21 with the water-soluble ink 22 (printing step; arrow (B1) in FIG. 2). Copper is thinly deposited thereon to form a copper thin film 23 having a mesh pattern (deposition step; arrow (B2) in FIG. 2). Further, the water-soluble ink 22 is removed by washing to obtain a mesh-like metal conductive layer 24 (cleaning step; arrow (B3) in FIG. 2). Patent Document 1 discloses such a manufacturing method.

  According to this method, in the mesh metal of the light-transmitting electromagnetic wave shielding material, the mesh line width can be sufficiently reduced and the aperture ratio can be increased. However, the film thickness of the metal conductive layer is small. Therefore, in order to impart a suitable conductivity to the above-described light-transmitting electromagnetic wave shielding layer, a copper thin film 25 is further electroplated on the metal conductive layer 24 to increase the thickness of the copper, It is desirable to form a sufficiently thick copper layer (plating step; arrow (B4) in FIG. 2).

  The light-transmitting electromagnetic wave shielding material thus obtained remains a metallic luster on the surface of the copper layer. Become. For this reason, in order to obtain a light-transmitting electromagnetic wave shielding layer for the PDP front filter, a blackening treatment for imparting antiglare properties is usually performed. That is, the surface of the metal copper is subjected to treatment such as oxidation or sulfuration to form an antiglare blackening treatment layer (blackening treatment step).

JP 2001-332889 A

  As described above, in the conventional manufacturing method, a light-transmitting electromagnetic wave shielding material is produced through a plurality of processes such as a printing process, a vapor deposition process, a cleaning process, a plating process, and, if necessary, a blackening process. However, the light-transmitting electromagnetic wave shielding material is desired to be improved in productivity. For this purpose, it is necessary to improve the production efficiency by reducing the number of processes or omitting the vapor deposition process.

  Accordingly, an object of the present invention is to provide a method for producing a light-transmitting electromagnetic wave shielding material having improved production efficiency by reducing the number of steps and omitting a vapor deposition step.

  As a result of intensive studies in view of the above problems, the present inventors have conducted electroless plating using a mixture or reaction product of a silane coupling agent and an azole compound and an electroless plating pretreatment agent containing a noble metal compound. It has been found that the above problem can be solved by forming a metal conductive layer on a transparent substrate.

That is, the present invention applies a mixture or reaction product of a silane coupling agent and an azole compound, and an electroless plating pretreatment agent containing a noble metal compound on a transparent substrate, and dries it on the transparent substrate. Forming a pretreatment layer;
Forming a dot-shaped plating protective layer on the pretreatment layer; and forming a mesh-like metal conductive layer by electroless plating on the pretreatment layer exposed without forming the plating protective layer The process of
The above-mentioned problems are solved by a method for producing a light-transmitting electromagnetic wave shielding material containing

  As the silane coupling agent, an epoxy group-containing silane compound, particularly γ-glycidoxypropyltrialkoxysilane is preferably used because high catalytic activity and adhesion can be obtained.

  As the azole compound, imidazole is preferably used because of its excellent reactivity with functional groups such as epoxy groups and noble metal compounds possessed by the silane coupling agent.

  As the noble metal compound, a compound containing a metal atom such as palladium, silver, platinum and gold is preferably used. With these noble metal compounds, high catalytic activity can be obtained.

  In the step of forming the pretreatment layer on the transparent substrate, the drying is performed at 80 to 160 ° C. Thereby, it is possible to obtain a pretreatment layer having a uniform thickness and excellent adhesion and catalytic activity.

  In addition, since the plating protective layer desirably has high light transmittance, the plating protective layer includes at least one selected from the group consisting of acrylic resin, polyester resin, vinyl chloride resin, and styrene resin. It is good.

  Moreover, since the said metal conductive layer can improve the adhesiveness with a pre-processing layer and a plating protective layer, and electromagnetic wave shielding property, it is preferable that silver, copper, or aluminum is included.

  Furthermore, in the method of the present invention, the metal conductive layer is blackened to impart antiglare properties to the metal conductive layer, and a blackened layer is formed on at least a part of the surface of the metal conductive layer. You may have the process further. The blackening treatment may be performed by oxidizing or sulfiding the metal conductive layer.

  According to the method of the present invention, since a mesh-like metal conductive layer having a sufficient thickness can be formed by electroless plating instead of vapor deposition, the number of steps can be reduced, and light-transmitting electromagnetic waves with improved manufacturing efficiency can be obtained. It becomes possible to provide the manufacturing method of a shielding material. As a result, it is possible to provide a light-transmitting electromagnetic wave shielding material with reduced manufacturing costs and a display filter using the same.

The method of the present invention basically comprises the following steps:
Forming a pretreatment layer on a transparent substrate using a predetermined electroless plating pretreatment agent;
Forming a dot-shaped plating protective layer on the pretreatment layer, and forming a metal conductive layer by electroless plating on the exposed pretreatment layer.

  An example of a schematic cross-sectional view for explaining each step of the production method of the present invention is shown in FIG. In the method of the present invention, first, a mixture or reaction product of a silane coupling agent and an azole compound, and an electroless plating pretreatment agent containing a noble metal compound are applied onto the transparent substrate 11 and dried, and the transparent A pretreatment layer 12 is formed on the substrate 11 (arrow (A1) in FIG. 1). In the electroless plating pretreatment agent, by using a silane coupling agent, an azole compound, and a noble metal compound, the metal conductive layer in which the silane coupling agent and the azole compound are formed by electroless plating with a transparent substrate. The noble metal compound which is an electroless plating catalyst can be dispersed at the atomic level in the pretreatment layer. Thereby, a transparent pretreatment layer can be obtained as compared with the case where noble metal particles are used as the electroless plating catalyst. In the conventional general electroless plating method, means for physically adsorbing the electroless plating catalyst on the surface roughened with chromic acid or the like is used. Therefore, when such a means is used, not only the transparent substrate is easily roughened but also the electroless plating catalyst is in a particle state, which may cause the substrate to become opaque. Similarly, the catalyst paint containing the electroless plating catalyst used in the conventional electroless plating method is similarly opaque because the catalyst metal or compound thereof is compounded in the particle state, and the catalyst paint is not transparent. The coated substrate became opaque and could not be used in the method of the present invention. However, according to the pretreatment agent used in the present invention, in addition to having high transparency, a pretreatment layer having high catalytic activity and ensuring adhesion without roughening the substrate surface or the like with a coupling agent. Furthermore, there is no limitation that the transparent substrate is easily roughened.

  Next, in the method of the present invention, a dot-shaped plating protective layer 13 is formed on the pretreatment layer 12 (arrow (A2) in FIG. 1). The plating protective layer 13 is for suppressing electroless plating on a predetermined portion on the pretreatment layer 12 when the metal conductive layer 14 is formed by performing electroless plating in a later step. Is. By providing a large number of dot-shaped plating protective layers 13 on the pretreatment layer 12, the metal conductive layer 14 is formed in the gap between the plating protective layers 13, and the plating protective layer 13 provides openings in the metal conductive layer 14. The mesh-shaped metal conductive layer 14 is formed.

  Next, in the method of the present invention, a mesh-like metal conductive layer 14 is formed by electroless plating on the pretreatment layer 11 exposed without forming the plating protective layer 13 (arrow in FIG. 1). (A3)). As a result, fine metal particles are deposited and formed as a dense and substantially continuous film between the numerous plating protective layers 13 and on the pretreatment layer exposed at the peripheral edge, and the metal conductive layer in close contact with the pretreatment layer is formed. Can be obtained. Further, by using electroless plating for forming the metal conductive layer, a metal conductive layer having a sufficient thickness can be easily formed, and manufacturing efficiency can be improved.

  Therefore, according to the present invention, it is possible to provide a method for producing a light-transmitting electromagnetic wave shielding material that is excellent in light transmittance, electromagnetic wave shielding properties, and production efficiency, without being limited to those in which the transparent substrate is easily roughened. Become.

  Below, the manufacturing method of the light transmissive electromagnetic wave shielding material of this invention is demonstrated in detail later on in order.

  First, in the method of the present invention, a mixture or reaction product of a silane coupling agent and an azole compound, and an electroless plating pretreatment agent containing a noble metal compound are applied onto a transparent substrate, dried, and then the transparent substrate. A step of forming a pretreatment layer thereon is performed.

  The pretreatment layer may be formed at least on a portion where the metal conductive layer can be formed on the transparent substrate, but the metal conductive layer is formed on the transparent substrate in order to facilitate formation and improve manufacturing efficiency. Preferably, the pretreatment layer is formed on the entire surface to be processed.

  In the electroless plating pretreatment agent, the silane coupling agent and the azole compound may be simply mixed, but may be reacted in advance to form a reaction product. As a result, the precious metal compound can be more highly dispersed at the atomic level in the pretreatment layer, and the light transmittance of the resulting pretreatment layer can be improved.

  In order to react the silane coupling agent with the azole compound, for example, 0.1 to 10 mol of silane coupling agent is mixed with 1 mol of azole compound at 80 to 200 ° C. for 5 minutes to It is preferable to react for 2 hours. At that time, a solvent is not particularly required, but an organic solvent such as chloroform, dioxanemethanol, ethanol or the like may be used in addition to water. The electroless plating pretreatment agent is obtained by mixing a noble metal compound with the reaction product of the silane coupling agent and the azole compound thus obtained.

  As the silane coupling agent used for the electroless plating pretreatment agent, it is preferable to use a silane coupling agent having a functional group having metal-capturing ability in one molecule. Thereby, it becomes possible to set it as the electronic state and orientation which express the activity of the noble metal compound which is an electroless-plating catalyst effectively, and high adhesiveness with a to-be-plated material is obtained.

  An example of the silane coupling agent is an epoxy group-containing silane compound. Examples of the epoxy group-containing silane compound include γ-glycidoxypropyltrialkoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3-glycidoxypropyltriethoxysilane. , 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and the like. These may be used alone or in combination of two or more. In particular, γ-glycidoxypropyltrialkoxysilane is preferred because the pretreatment layer obtained has high light transmittance.

  Next, the azole compound used in the electroless plating pretreatment agent includes imidazole, oxazole, thiazole, selenazole, pyrazole, isoxazole, isothiazole, triazole, oxadiazole, thiadiazole, tetrazole, oxatriazole, thia Examples include triazole, benzazole, indazole, benzimidazole, benzotriazole, and indazole. Although not limited to these, imidazole is particularly preferable because it is excellent in reactivity with a functional group such as an epoxy group of the silane coupling agent and a noble metal compound.

  Next, the noble metal compound used in the pretreatment agent for electroless plating exhibits a catalytic effect capable of selectively depositing and growing a metal such as copper or aluminum from an electroless plating solution. Specifically, it is preferable to use a compound containing a metal atom such as palladium, silver, platinum, and gold because high catalytic activity is obtained. Examples of the compound include chlorides, hydroxides, oxides, sulfates, ammonium salts, and the like of the metal atom, and palladium compounds, particularly palladium chloride is preferable.

  The electroless plating pretreatment agent preferably contains 0.001 to 50 mol%, more preferably 0.1 to 20 mol%, of the noble metal compound with respect to the azole compound and the silane coupling agent. If the concentration of the noble metal compound is less than 0.001 mol%, sufficient catalytic activity may not be obtained and a metal conductive layer having a desired thickness may not be formed. If the concentration exceeds 50 mol%, an increase in the amount added is commensurate. There is a risk that the catalytic effect of the noble metal compound cannot be obtained.

  Moreover, the said electroless-plating pretreatment agent may contain the suitable solvent. Examples of the solvent include water, methyl alcohol, ethyl alcohol, 2-propanol, acetone, toluene, ethylene glycol, polyethylene glycol, dimethylformamide, dimethyl sulfoxide, and dioxane. These may be used individually by 1 type and may be used in mixture of 2 or more types.

  The electroless plating pretreatment agent may further contain various additives such as extender pigments, surfactants, and colorants as necessary.

  In the method of the present invention, the transparent substrate to which the pretreatment agent is applied is not particularly limited as long as it has transparency and flexibility and can withstand subsequent processing. Examples of the material of the transparent substrate include glass, polyester (eg, polyethylene terephthalate, (PET), polybutylene terephthalate), acrylic resin (eg, polymethyl methacrylate (PMMA)), polycarbonate (PC), polystyrene, cellulose triacetate, Polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyethylene, ethylene-vinyl acetate copolymer, polyvinyl butyral, metal ion crosslinked ethylene-methacrylic acid copolymer, polyurethane, cellophane, etc. PET, PC, and PMMA, which are less transparent due to processing (heating, solvent, bending) and are highly transparent, are preferable. The transparent substrate is used as a sheet, film, or plate made of these materials.

  The thickness of the transparent substrate is not particularly limited, but it is preferably as thin as possible from the viewpoint of maintaining the light transmittance of the light-transmitting electromagnetic wave shielding material, and is usually 0 depending on the form in use and the required mechanical strength. The thickness is appropriately set within a range of 0.05 to 5 mm.

  In order to apply the pretreatment agent on the transparent substrate, gravure reverse, gravure coat, micro gravure coat, lip coat, roll reverse coat, wire bar coat, kiss coat, die coat, roll coat, spin coat, air spray, airless spray In general, methods such as dipping and brushing are not limited thereto.

  In order to increase the curability of the film, the applied electroless plating pretreatment agent is preferably heated to 80 to 160 ° C, more preferably 120 to 140 ° C. If the heating temperature is less than 80 ° C., the evaporation rate of water is low and sufficient film forming properties cannot be obtained, and thus the adhesion between the pretreatment layer and the metal conductive layer may be lowered. On the other hand, when the temperature exceeds 160 ° C., the pretreatment layer forming material may be thermally decomposed to lower the adhesion, and may be discolored to lower the light transmittance. The drying time is preferably 1 second to 5 minutes.

  Next, in the method of the present invention, a step of forming a dot-like plating protective layer on the pretreatment layer is performed. According to the plating protective layer, when forming a metal conductive layer by performing electroless plating in a subsequent step, the plating is prevented from being performed on a predetermined portion on the pretreatment layer, and the front It becomes possible to form a metal conductive layer other than the portion where the plating protective layer is formed on the treatment layer, and a mesh-like metal conductive layer is obtained.

  The dot-shaped plating protective layer formed on the pretreatment layer is preferably formed by printing. Thereby, a plurality of dot-like plating protective layers having a desired pattern can be formed by a simple method.

  The plating protective layer is preferably formed on the pretreatment layer by printing a resist ink in which a resin resistant to an electroless plating solution is dissolved in a solvent.

  In the resist ink, the resin resistant to the electroless plating solution is preferably at least one selected from the group consisting of an acrylic resin, a polyester resin, a vinyl chloride resin, and a styrene resin. These may be used individually by 1 type and may be used in mixture of 2 or more types. If these resins, especially acrylic resins, the obtained plating protective layer has high adhesion with the pretreatment layer and the mesh-like metal conductive layer produced in the subsequent step, and has high light transmittance. . Therefore, it can be used as it is for the light-transmitting electromagnetic wave shielding material without removing the plating protective layer in a subsequent process, and the efficiency of the manufacturing process can be further increased.

  Among them, as the resin resistant to the electroless plating solution, an acrylic resin is particularly preferable. For example, alkyl acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, hexyl acrylate, and methyl methacrylate. Homopolymers of alkyl methacrylates such as ethyl methacrylate, butyl methacrylate and hexyl methacrylate can be used, and polymethyl methacrylate, polyethyl methacrylate or polybutyl methacrylate is particularly preferred.

  The resist ink may contain 5 to 50% by mass, more preferably 10 to 40% by mass of the resin. If the concentration of the resin is less than 5% by mass, a plating protective layer having a desired thickness may not be formed, and if it exceeds 50% by mass, the light transmittance of the obtained plating protective layer may be reduced.

  Any solvent can be used for the resist ink as long as it can dissolve the resin and has excellent film formability. Specifically, dichloromethane, tetrahydrofuran, cyclohexanone, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, methyl lactate, ethyl lactate, 2-ethoxyethyl acetate, methyl pyruvate, pyruvate Ethyl, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, cyclohexanone, methyl ethyl ketone, 2-heptanone, 1,4- Dioxane, diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, ethylene glycol monoisopropyl ether, toluene, vinegar Ethyl and butyl acetate.

  The resist ink may further contain a transparent filler or a polymer thickener in order to improve the printing finish.

  The viscosity of the resist ink is preferably 1000 to 5000 cps, more preferably 2500 to 4000 cps at 25 ° C. Thereby, the plating protective layer which has much better shape and dimensional accuracy is obtained.

  In order to print the resist ink on the pretreatment layer, a printing method such as gravure printing, screen printing, offset printing, inkjet printing, electrostatic printing, flexographic printing, or the like can be used. In particular, gravure printing is suitable for thinning. When using gravure printing, the printing speed is preferably 5 to 50 m / min.

  The plating protective layer may be printed by a transfer method. In the case of the transfer method, for example, a resist ink is printed on an arbitrary transfer base sheet different from the pretreatment layer by a printing method similar to the above, and a heat laminating method, a dry laminating method, or a wet laminating method. For example, a method in which only the transfer base sheet is peeled off and the resist ink is transferred to the pretreatment layer after being bonded to the pretreatment layer by a method, an extrusion lamination method, or the like can be used.

  A large number of the plating protective layers are formed on the pretreatment layer, and the region where the pretreatment layer is exposed in the recesses formed between the plating protection layers is preferably in a mesh shape such as a lattice shape or a mesh shape. Printed on. The shape of the plating protective layer is arbitrary, such as a circular shape, an elliptical shape, a rectangular shape, or a linear shape, but is preferably a rectangular shape, and particularly preferably a square shape. Thereby, the metal conductive layer which has high light transmittance and electromagnetic wave shielding property is obtained.

  The said plating protective layer is for forming the opening part in a mesh-shaped metal conductive layer at a next process. In order for the metal conductive layer to have high light transmittance, it is desirable that the metal conductive layer has a high aperture ratio and a small opening size. Accordingly, the size of the plating protective layer is preferably very small, and may be appropriately determined according to the size of the opening in the metal conductive layer to be obtained. For example, as the size of the plating protective layer having a square shape, particularly a square, the length of one side is preferably 100 to 400 μm, more preferably 200 to 300 μm.

  Further, from the viewpoint of imparting high light transmittance and electromagnetic wave shielding properties to the metal conductive layer, it is desirable that the dot-shaped plating protective layers are regularly arranged at equal intervals. The thickness of the plating protective layer is not particularly limited, but is preferably about 0.1 to 5 μm.

  In addition, as a metal conductive layer, a mesh pattern-shaped metal conductive layer is formed in the central portion on the pretreatment layer, and a frame-shaped metal conductive layer is formed in the peripheral portion excluding the central portion on the pretreatment layer. In order to form what has, it is sufficient to form the said plating protective layer only in the center part except the peripheral part on the said pretreatment layer.

  Thus, after printing the said resist ink, it is made to dry and the dot-like plating protective layer which consists of a very small number is obtained. The drying is preferably performed by heating the applied resist ink at 70 to 120 ° C., more preferably 90 to 110 ° C. If the heating temperature is less than 70 ° C., the evaporation rate of the solvent is slow and there is a possibility that sufficient film-forming properties may not be obtained, and if it exceeds 120 ° C., thermal decomposition of the resin may occur. The drying time for heat drying after coating is preferably 5 seconds to 5 minutes.

  The total light transmittance of the plating protective layer is preferably 85% or more, particularly 90% or more. Thereby, the electromagnetic wave shielding material which has high light transmittance is obtained.

  Next, in the method of the present invention, a step of forming a mesh-like metal conductive layer 14 by performing electroless plating on the pretreatment layer 11 exposed without forming the plating protective layer 13 is performed. By performing electroless plating, it is possible to obtain a metal conductive layer by depositing fine metal particles as a dense and substantially continuous film between and around the plating protective layer on the pretreatment layer. .

  The electroless plating can be performed according to a conventional method using an electroless plating bath. That is, the plating substrate is immersed in a bath containing a plating solution containing a plating metal salt, a chelating agent, a pH adjuster, a reducing agent, etc. as a basic composition, or a component plating solution is added separately from two or more solutions What is necessary is just to select suitably, such as performing a plating process by a system.

  The plating metal can be used as long as it is conductive and can be plated, and may be a single metal, an alloy, a conductive metal oxide, etc. It may be made of fine fine particles.

  As the metal contained in the metal conductive layer formed by electroless plating, aluminum, nickel, indium, chromium, gold, vanadium, tin, cadmium, silver, platinum, copper, titanium, cobalt, lead, or the like can be used. . In particular, silver, copper, or aluminum is preferably used because a metal conductive layer with high electromagnetic shielding properties can be obtained. The metal conductive layer formed using these plating metals is excellent in adhesion between the pretreatment layer and the plating protective layer, and is suitable for achieving both light transmittance and electromagnetic shielding properties. Therefore, electroless plating may be performed using these metals, and as an electroless plating bath, an electroless Cu plating bath, an electroless Ni plating bath, or the like can be used.

  Electroless plating is well known, and may be carried out at room temperature or under warming according to a conventional method by appropriately selecting and preparing chemicals. As an example of electroless plating, when forming a metal conductive layer made of Cu, a water-soluble copper salt such as copper sulfate 1 to 100 g / L, particularly 5 to 50 g / L, a reducing agent such as formaldehyde 0.5 to 0.5 10 g / L, especially 1 to 5 g / L, a solution containing 20 to 100 g / L, particularly 30 to 70 g / L of a complexing agent such as EDTA, and adjusted to pH 12 to 13.5, particularly 12.5 to 13 A method of immersing the transparent substrate on which the pretreatment layer and the plurality of plating protective layers are formed at 50 to 90 ° C. for 30 seconds to 60 minutes can be employed.

  Further, when performing electroless plating, the substrate to be plated may be rocked and rotated, or the vicinity thereof may be agitated with air.

  The metal conductive layer preferably has a line width of 50 μm or less, particularly preferably 40 μm or less, especially 10 to 30 μm. The metal conductive layer is preferably a mesh pattern having an aperture ratio of 75% or more. In addition, the aperture ratio said here means the total area of the hole with respect to the use effective area of a metal conductive layer.

  The mesh pattern of the metal conductive layer is preferably a geometric pattern, and the shape of the hole is appropriately selected from a parallelogram such as a square or a rectangle, a circle or a regular hexagon (honeycomb shape). In addition, since it is important that any part has certain characteristics (mainly light transmission property, electromagnetic wave shielding property, etc.), it is preferably arranged regularly.

  In addition, the metal conductive layer has a configuration in which a mesh pattern-shaped metal conductive layer is formed in the central portion on the pretreatment layer, and a frame-shaped metal conductive layer is formed in the peripheral portion excluding the central portion on the pretreatment layer. There may be. Such a configuration is desirable for protecting the metal conductive layer having a mesh pattern.

  In the method of the present invention, if necessary, electrolytic plating may be further performed on the metal conductive layer.

  In the method of the present invention, as shown in FIG. 1, the metal conductive layer 14 is blackened and a blackened layer 15 is formed on at least a part of the surface of the metal conductive layer 14 (arrow in FIG. 1). (A4)) may be further performed.

  The blackening treatment is preferably performed by metal oxidation treatment or sulfurization treatment of the metal conductive layer. In particular, the oxidation treatment can obtain a more excellent antiglare effect, and is also preferable from the viewpoint of simplicity of waste liquid treatment and environmental safety.

  When the oxidation treatment is performed as the blackening treatment, the blackening treatment liquid is generally a mixed aqueous solution of hypochlorite and sodium hydroxide, a mixed aqueous solution of chlorite and sodium hydroxide, peroxodisulfuric acid, It is possible to use a mixed aqueous solution of sodium hydroxide, etc. Especially from the economical point of view, a mixed aqueous solution of hypochlorite and sodium hydroxide or a mixed aqueous solution of chlorite and sodium hydroxide is used. It is preferable to do.

  In the case of performing sulfurization treatment as the blackening treatment, it is generally possible to use an aqueous solution such as potassium sulfide, barium sulfide and ammonium sulfide as the blackening treatment liquid, preferably potassium sulfide and ammonium sulfide. In particular, ammonium sulfide is preferably used because it can be used at a low temperature.

  According to the method of the present invention, as described above, a predetermined electroless plating is performed to easily form a metal conductive layer having a sufficient thickness, and preferably a plating protective layer having a high total light transmittance is formed. Thus, it is possible to provide a light-transmitting electromagnetic wave shielding material whose manufacturing efficiency can be improved by reducing the number of manufacturing steps and whose manufacturing cost is reduced. Moreover, since it is not necessary to roughen the base material, it is possible to provide a light-transmitting electromagnetic wave shielding material in which the transparent substrate and the pretreatment layer have high light transmittance.

  The light-transmitting electromagnetic wave shielding material is provided without a transparent substrate, a pretreatment layer provided on the transparent substrate, a dot-like plating protective layer provided on the pretreatment layer, and the plating protective layer. A mesh-like metal conductive layer provided on the exposed pretreatment layer, wherein the pretreatment layer contains a mixture or reactive organism of a silane coupling agent and an azole compound, and a noble metal compound. It has the structure which is a coating layer of an electroplating pretreatment agent. The light-transmitting electromagnetic wave shielding material having the above-described configuration can be manufactured easily and at low cost by the method of the present invention described above.

  The light-transmitting electromagnetic wave shielding material has a high light transmittance in the pretreatment layer and the transparent substrate by using an electroless plating pretreatment agent containing a predetermined component. Therefore, the total light transmittance of the light transmissive electromagnetic wave shielding material can be 75% or more, particularly 80 to 90%.

  In addition, the measurement of the total light transmittance of the light-transmitting electromagnetic wave shielding material is performed using the fully automatic direct reading haze computer HGM-2DP (manufactured by Suga Test Instruments Co., Ltd.) and the like in the thickness direction of the light-transmitting electromagnetic wave shielding material. This is done by measuring the light transmittance.

  The light transmissive electromagnetic wave shielding material may have a blackening treatment layer on at least a part of the surface of the metal conductive layer in order to impart antiglare properties to the metal conductive layer.

  In addition, since detailed description about each layer of the said light-transmitting electromagnetic wave shielding material is as above-mentioned in the manufacturing method of this invention, it abbreviate | omits here.

  The light-transmitting electromagnetic wave shielding material according to the present invention is used for applications requiring light transmission, for example, display surfaces of display devices such as LCDs, PDPs, and CRTs of various electric devices that generate electromagnetic waves, or transparent glass for facilities and houses. It is suitably applied to surfaces and transparent panel surfaces. Since the light transmissive electromagnetic wave shielding material has high light transmissive property and electromagnetic wave shielding property, it is suitably used for the display filter of the display device described above.

  The display filter of the present invention is not particularly limited, but can be obtained by laminating a light-transmitting electromagnetic wave shielding material produced by the above method on a transparent substrate such as a glass plate.

  Hereinafter, the present invention will be described with reference to examples. The present invention is not limited by the following examples.

Example 1
In an aqueous solution containing 5 wt% of a reaction product obtained by mixing imidazole with γ-glycidoxypropyltrimethoxysilane at a molar ratio of 1: 1 and reacting for 1 hour and 100 minutes, While stirring at 25 ° C., palladium chloride was added to prepare a solution having a palladium chloride concentration of 10 g / L. This was diluted 100 volume times with n-butanol to prepare a pretreatment agent having a palladium chloride concentration of 100 mg / L. The solution thus obtained was coated on a glass slope (thickness 5 mm) so that the coating amount was 2 g / m ² and dried at 160 ° C. for 5 minutes. Thereby, the pretreatment layer was formed on the glass slope.

  Next, a resist ink containing 30 wt% of polymethyl methacrylate resin in a solvent containing dichloromethane, tetrahydrofuran, and cyclohexanone at a mass ratio of 20:60:20 is formed into dots on the pretreatment layer by gravure offset printing. Printing was performed to form a plating protective layer composed of a large number of minute protrusions on the pretreatment layer. The size of one dot is a square having a side of 234 μm, the interval between dots is 20 μm, and the dot arrangement is a square lattice. The printing thickness was 3 μm after drying.

  The glass slope on which the plating protective layer and the pretreatment layer thus obtained were formed was immersed in an electroless copper plating solution (Melplate CU-5100 manufactured by Meltex Co., Ltd.) at 50 ° C. for 20 minutes. An electroless copper plating treatment was performed to obtain a grid-like metal conductive layer. The metal conductive layer had a thickness of 1.5 μm, a line width of 23 μm, and an aperture ratio of 83%.

  Furthermore, the blackening process of the following composition was performed with respect to the glass plate in which the metal conductive layer obtained above was formed.

Blackening solution composition (aqueous solution)
Sodium chlorite: 10% by mass
Sodium hydroxide: 4% by mass
Blackening conditions Bath temperature: Approx. 60 ° C
Time: 5 minutes

  By this blackening treatment, a light-transmitting electromagnetic wave shielding material in which the surface of the metal conductive layer was blackened was obtained. The blackened thickness of the surface of the obtained light transmissive electromagnetic wave shielding material was 1.5 μm on average.

  As described above, in the present invention, it is possible to obtain a light transmissive electromagnetic wave shielding material which is simpler than conventional methods and which is excellent in light transmittance and electromagnetic wave shielding properties.

It is the figure explaining each process of the manufacturing method of the light transmission electromagnetic wave shielding material by this invention using sectional drawing. It is the figure explaining each process of the manufacturing method of the conventional light-transmitting electromagnetic wave shielding material using sectional drawing.

Explanation of symbols

11 Transparent substrate,
12 Pretreatment layer,
13 plating protective layer,
14 metal conductive layer,
15 Blackening treatment layer,
21 transparent substrate,
22 Water-soluble ink,
23 Copper thin film,
24 metal conductive layer,
25 Copper thin film.

Claims (15)

An electroless plating pretreatment agent containing a mixture or reaction product of a silane coupling agent and an azole compound and a noble metal compound is applied on a transparent substrate and dried to form a pretreatment layer on the transparent substrate. Process,
Forming a dot-shaped plating protective layer on the pretreatment layer; and forming a mesh-like metal conductive layer by electroless plating on the pretreatment layer exposed without forming the plating protective layer The process of
A method for producing a light-transmitting electromagnetic wave shielding material comprising:   The method for producing a light-transmitting electromagnetic wave shielding material according to claim 1, wherein the silane coupling agent is an epoxy group-containing silane compound.   The method for producing a light-transmitting electromagnetic wave shielding material according to claim 1, wherein the silane coupling agent is γ-glycidoxypropyltrialkoxysilane.   The method for producing a light-transmitting electromagnetic wave shielding material according to claim 1, wherein the azole compound is imidazole.   The method for producing a light-transmitting electromagnetic wave shielding material according to claim 1, wherein the noble metal compound is a compound containing at least one metal atom selected from the group consisting of palladium, silver, platinum, and gold. .   The method for producing a light-transmitting electromagnetic wave shielding material according to any one of claims 1 to 5, wherein in the step of forming the pretreatment layer on the transparent substrate, the drying is performed at 80 to 160 ° C.   The light-transmitting electromagnetic wave shielding material according to claim 1, wherein the plating protective layer contains at least one selected from the group consisting of an acrylic resin, a polyester resin, a vinyl chloride resin, and a styrene resin. Method.   The method for producing a light-transmitting electromagnetic wave shielding material according to claim 1, wherein the metal conductive layer contains silver, copper, or aluminum.   The light-transmitting electromagnetic wave shielding material according to claim 1, further comprising a step of blackening the metal conductive layer and forming a blackened layer on at least a part of the surface of the metal conductive layer. Production method.   The method for producing a light-transmitting electromagnetic wave shielding material according to claim 9, wherein the blackening treatment is performed by oxidizing or sulfurating the metal conductive layer.   The light transmissive electromagnetic wave shielding material manufactured by the manufacturing method in any one of Claims 1-10. On the transparent substrate, the pretreatment layer provided on the transparent substrate, the dot-like plating protective layer provided on the pretreatment layer, and the pretreatment layer exposed without being provided with the plating protective layer Having a mesh-like metal conductive layer provided;
The light-transmitting electromagnetic wave shielding material, wherein the pretreatment layer is a coating layer of an electroless plating pretreatment agent containing a mixture or reactive organism of a silane coupling agent and an azole compound and a noble metal compound.   The light transmissive electromagnetic wave shielding material according to claim 12, wherein the total light transmittance is 75% or more.   The light-transmitting electromagnetic wave shielding material according to claim 12 or 13, further comprising a blackening treatment layer on at least a part of the surface of the metal conductive layer. A display filter comprising the light-transmitting electromagnetic wave shielding material according to claim 11.

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