JP2008041823A - Light transmitting electromagnetic wave shielding material, production process thereof, and filter for display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simple production process of a light transmitting electromagnetic wave shielding material having a mesh pattern of high precision and excellent in optical transmittance, electromagnetic wave shielding performance, appearance, and visibility. <P>SOLUTION: The production process of a light transmitting electromagnetic wave shielding material comprises steps of: (A1) forming a mesh type preprocessing layer 12 on a transparent substrate 11, by printing an electroless plating preprocessing agent containing a mixture or a rection product of a silane coupling agent and an azole based compound, and a noble metal compound onto the transparent substrate 11; and (A2) forming mesh type metal conductive layer 13 on the preprocessing layer 12 by electroless plating. <P>COPYRIGHT: (C)2008,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. For this purpose, for example, (1) a material having an electromagnetic wave shielding layer made of a conductive mesh in which a metal wire or a conductive fiber is made into a net is provided on one surface of a transparent substrate. The Electromagnetic waves are shielded by the conductive mesh portion, and light transmission is ensured by the opening.

  In addition, various types of light transmissive electromagnetic wave shielding materials have been proposed as filters for electronic displays. For example, (2) a transparent substrate provided with a transparent conductive thin film containing metallic silver, (3) a layer of copper foil or the like on the transparent substrate is etched into a net shape, and an opening is provided, (4) a transparent substrate In general, a conductive ink containing conductive powder printed on a mesh is known.

  Thus, in the electromagnetic wave shielding layer, in order to achieve both excellent light transmittance and electromagnetic wave shielding properties, it is necessary to use a mesh-like transparent conductive layer, extremely narrow the line width, and form a very fine pattern. However, with the above-described conventional light-transmitting electromagnetic wave shielding material, it is difficult to achieve both light transmission and electromagnetic wave shielding sufficiently. That is, the light-transmitting electromagnetic wave shielding material (1) has a limitation in thinning, and it is difficult to obtain a fine mesh pattern, and there is a problem that the arrangement of fibers such as misalignment and bending is disturbed. In the case of the light-transmitting electromagnetic wave shielding material (2), there are problems such as insufficient electromagnetic wave shielding properties and strong reflection gloss specific to metals. In the light transmissive electromagnetic wave shielding material of (3), the manufacturing process is long, the cost is high, and the light transmittance is low because the adhesive layer is interposed between the transparent substrate and the copper foil layer. There's a problem. Further, in the light transmissive electromagnetic wave shielding material of (4), it is difficult to obtain sufficient electromagnetic wave shielding properties. If the pattern is thickened to increase the electromagnetic shielding properties and the amount of conductive powder is increased, There are problems such as a decrease in permeability.

  However, the production of the light-transmitting electromagnetic wave shielding material of (4) above uses, for example, a conductive ink containing a conductive powder such as a metal powder or carbon powder and a resin by an intaglio offset printing method on a transparent substrate. This is performed using a method for forming a print pattern. Therefore, the light-transmitting electromagnetic wave shielding material (4) has an advantage that it can be manufactured by a simple method and at a low cost without requiring an etching process.

  Therefore, as an improvement of the technique of (4) above, in Patent Documents 1 to 6, in order to further improve the electromagnetic wave shielding property after forming a printing pattern on the transparent substrate with the conductive ink by the intaglio offset printing method. A method of selectively forming a metal layer on the printed pattern by electroless plating or electrolytic plating is disclosed.

  Further, in Patent Document 7, pattern printing is performed using a paste containing a carrier prepared by supporting the noble metal ultrafine particle catalyst on particles having a surface charge opposite to that of the noble metal ultrafine particle catalyst on a transparent substrate. A method for producing a light-transmitting electromagnetic wave shielding material is disclosed in which an electroless plating process is performed on a printed noble metal ultrafine particle catalyst to form a conductive metal layer only on a pattern printing portion.

Japanese Patent No. 3017987 Japanese Patent No. 3017988 Japanese Patent No. 3241348 Japanese Patent No. 3425400 Japanese Patent No. 3544498 Japanese Patent No. 3532146 Japanese Patent No. 336383

  However, since the light-transmitting electromagnetic wave shielding material according to Patent Documents 1 to 7 described above is difficult to form a fine pattern by accurately printing a conductive ink or paste, the light transmitting property and the electromagnetic wave shielding property. Still leaves room for improvement. Furthermore, in the light transmissive electromagnetic wave shielding material, streaks and fog, which are peculiar problems due to printing, are formed, and there is a problem that not only the appearance of the electronic display is deteriorated but also the visibility is lowered.

  Accordingly, an object of the present invention is to provide a light-transmitting electromagnetic wave shielding material having a high-accuracy mesh pattern, which is excellent in light transmittance, electromagnetic wave shielding property, appearance, and visibility, and can be produced by a simple method. Is to provide a method.

  The above-described problem is considered to be caused by the presence of a carrier having conductive powder or a noble metal ultrafine particle catalyst in a conductive ink or paste used for manufacturing a conventional light-transmitting electromagnetic wave shielding material. That is, in order to form a layer having a uniform thickness by reducing the contact resistance, these conductive powders and carriers are used with powders having a fine particle diameter. A powder having a small particle size tends to cause aggregation. Therefore, in the conductive ink or paste, it is considered that the above-mentioned problems are caused by aggregation of the conductive powder and the noble metal ultrafine particle catalyst.

  Therefore, as a result of various studies focusing on the above problems, the present inventors have replaced silane coupling agents, azole compounds, and noble metals in place of conductive inks and pastes used in conventional electromagnetic shielding materials. It discovered that the said subject could be solved by manufacturing a light-transmitting electromagnetic wave shielding material using the electroless-plating pretreatment agent containing a compound.

That is, the present invention prints the mixture or reaction product of a silane coupling agent and an azole-based compound and an electroless plating pretreatment agent containing a noble metal compound in a mesh form on a transparent substrate. Forming a mesh-like pretreatment layer on a substrate; and forming a mesh-like metal conductive layer on the pretreatment layer by electroless plating;
The above-mentioned problems are solved by a method for producing a light-transmitting electromagnetic wave shielding material containing

  Hereinafter, the preferable aspect of the manufacturing method of the light transmissive electromagnetic wave shielding material of this invention is listed below.

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

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

  (3) As said noble metal compound, the compound containing metal atoms, such as palladium, silver, platinum, and gold | metal | money, is used. With these noble metal compounds, high catalytic activity can be obtained.

  (4) The electroless plating pretreatment agent is printed in a mesh on the transparent substrate, and then dried at 80 to 160 ° C. Thereby, a pretreatment layer having a fine pattern can be formed.

  (5) The metal conductive layer contains silver, copper, or aluminum because it can improve the adhesion with the pretreatment layer and the plating protective layer and the electromagnetic wave shielding property.

  (6) After performing the electroless plating, electrolytic plating is further performed. Thereby, a metal conductive layer having a desired thickness can be obtained.

  (7) The method further includes 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. Thereby, the glare-proof property can be provided to the said metal conductive layer, and visibility can be improved.

  According to the method of the present invention, by forming a metal conductive layer on a pretreatment layer formed using an electroless plating pretreatment agent containing a silane coupling agent, an azole compound, and a noble metal compound, It is possible to obtain a metal conductive layer having a uniform pattern and accurately formed with a uniform thickness. In the pretreatment layer, the silane coupling agent, the azole compound, and the noble metal compound are dispersed at the atomic level, so that no streaking or fogging occurs.

  Therefore, according to the method of the present invention, it is possible to provide a light transmissive electromagnetic wave shielding material excellent in light transmissive property, electromagnetic wave shielding property, appearance and visibility.

  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 printed on the transparent substrate 11 in a mesh shape, A mesh-shaped pretreatment layer 12 is formed on the transparent substrate 11 (arrow (A1) in FIG. 1).

  According to the electroless plating pretreatment agent, the silane coupling agent, the azole compound, and the noble metal compound can be dispersed at the atomic level in the pretreatment layer, and conventionally used fine metal powder and conductive material can be dispersed. Does not contain sexual powder. Therefore, it is possible to accurately form a mesh-shaped pretreatment layer having a fine pattern free from streaking and fogging. Furthermore, the pretreatment layer formed using the electroless plating pretreatment agent exhibits adhesion between the transparent substrate and the metal conductive layer by the silane coupling agent and the azole compound, and the precious metal compound is free from the pretreatment layer. It exhibits a catalytic effect in depositing metals in electrolytic plating. Accordingly, a metal conductive layer can be selectively formed on the pretreatment layer by electroless plating in a later step, and mesh-like metal conductivity having a desired thickness can be obtained.

  Next, in the method of the present invention, a metal conductive layer 13 is formed on the mesh-shaped pretreatment layer 12 by performing an electroless plating process (arrow (A2) in FIG. 1).

  Thereby, fine metal particles are deposited and formed as a dense and substantially continuous film on the pretreatment layer formed using the noble metal compound, and selectively adheres to the pretreatment layer and has a fine pattern. A metal conductive layer can be obtained.

  Thus, according to the present invention, a metal conductive layer having a fine pattern can be formed by a simple method, and a light-transmitting electromagnetic wave shielding material excellent in both light transmission and electromagnetic wave shielding properties is provided. It becomes possible. Further, since the pretreatment agent does not contain powdery particles, it is possible to provide a light-transmitting electromagnetic wave shielding material that has no appearance of streaks and fog due to particle aggregation and is excellent in appearance and visibility. It becomes.

  Below, the manufacturing method of the electromagnetic 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 printed in a mesh on a transparent substrate, A step of forming a mesh-shaped pretreatment layer on the transparent substrate is performed.

  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 to be obtained exhibits high adhesion to the transparent substrate and the metal conductive layer.

  Next, the azole compounds used in the electroless plating pretreatment agent include 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.

  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.

  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 in the electroless plating treatment. 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 the method of the present invention, a mesh-shaped pretreatment layer is formed on the transparent substrate by printing the above-described electroless plating pretreatment agent on the transparent substrate in a mesh shape. Thereby, a plating protective layer having a desired fine pattern can be formed by a simple method.

  The viscosity of the electroless plating pretreatment agent is preferably 500 to 5000 cps, more preferably 1000 to 3000 cps at 25 ° C. in order to obtain a pretreatment layer having a fine line width and a gap (pitch) by printing. It is good to do.

  In order to print the electroless plating pretreatment agent on the transparent substrate, a printing method such as gravure printing, screen printing, offset printing, ink jet 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 pretreatment layer may be printed by a transfer method. In the case of the transfer method, for example, an electroless plating pretreatment agent is printed on an arbitrary transfer base sheet different from the transparent substrate by a printing method similar to the above, a heat laminating method, a dry laminating method, Or after laminating with the transparent substrate by wet laminating method, extrusion laminating method, etc., only the base material sheet for transfer is peeled off, and a method of transferring the electroless plating pretreatment agent to the pretreatment layer is used. be able to.

  Thus, after printing the electroless plating pretreatment agent, it is preferably dried by heating at 80 to 160 ° C., more preferably 90 to 130 ° C. If the drying temperature is less than 80 ° C., the evaporation rate of the solvent is slow and there is a possibility that sufficient film formability may not be obtained, and if it exceeds 160 ° C., thermal decomposition of the compound may occur. The drying time for heat drying after coating is preferably 5 seconds to 5 minutes.

  The shape of the pattern in the mesh-shaped pretreatment layer is not particularly limited, and examples thereof include a lattice shape in which square holes are formed, and a punching metal shape in which circular, hexagonal, triangular or elliptical holes are formed. It is done. Further, the holes are not limited to those regularly arranged, and may be a random pattern.

  From the viewpoint of imparting high light transmittance and electromagnetic wave shielding properties to the metal conductive layer, it is desirable that the openings in the pretreatment layer are regularly arranged at equal intervals. In order to form a metal conductive layer having a high light transmittance, it is desirable that the shape of the opening in the metal conductive layer is a square shape, particularly a square or a rectangle, and the aperture ratio is high. Therefore, it is preferable that the size of the opening in the pretreatment layer is very small. For example, FIG. 2 shows an example of the pattern of the pretreatment layer 12 in which the shape of the opening 15 is a square.

In the pretreatment layer, the line width (W ₁ ) is _{1 to} 50 μm and the aperture ratio is 50 to 95%, preferably the line width (W ₁ ) is 5 to 40 μm and the aperture ratio is 60 to 95%. The aperture ratio of the pretreatment layer refers to the area ratio occupied by the opening portion in the projected area of the pretreatment layer (the area excluding the outer frame if there is an outer frame). In the pretreatment layer, the line spacing (W ₂ ) is 50 to 1000 μm, preferably 100 to 400 μm. Thus, according to the present invention, a pretreatment layer having a fine pattern can be formed with high accuracy.

  The pretreatment layer may have the mesh-like pattern described above at the central portion on the transparent substrate, and may have a frame-like pattern at the peripheral portion excluding the central portion on the transparent substrate. If a metal conductive layer is formed on the pretreatment layer having such a configuration, a portion having a frame-like pattern in the metal conductive layer can protect a portion having a mesh-like pattern.

  The pretreatment layer has a thickness of 0.01 to 2 μm, preferably 0.05 to 0.5 μm. Thereby, the high adhesiveness with a transparent substrate and a metal conductive layer is securable.

  Next, in the method of the present invention, a step of forming a mesh-like metal conductive layer by electroless plating treatment is performed on the pretreatment layer formed as described above. By performing the electroless plating treatment, fine metal particles are deposited and formed as a dense and substantially continuous film, and a metal conductive layer can be selectively obtained only on the pretreatment layer.

  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 a plating metal in 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 wave shielding properties.

  The electroless plating can be performed at room temperature or under heating 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.

  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.

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

  In the method of the present invention, after the electroless plating is performed on the transparent substrate on which the pretreatment layer is formed so that the metal conductive layer has a desired thickness and line width, the electrolytic plating may be further performed. Good.

  As the plating metal in the electroplating, the same metal as described above in the electroless plating is used.

  Electroplating is not particularly limited, and may be performed according to a conventional method. For example, a transparent substrate on which a mesh-shaped pretreatment layer and a metal conductive layer are formed is immersed in a plating solution, the transparent substrate is used as a cathode, a single plating metal is used as an anode, and an electric current is applied to the plating solution. . The composition of the plating solution is not particularly limited. For example, when forming a metal conductive layer made of Cu, an aqueous copper sulfate solution or the like is used.

  There is no restriction | limiting in particular in the shape of the pattern in a mesh-shaped metal conductive layer, It is the same as that mentioned above in the pretreatment layer.

In the metal conductive layer, line width (W ₁₎ 1 to 50 [mu] m, an aperture ratio from 50% to 95%, preferably the line width (W ₁₎ 5 to 40 m, preferably set to aperture ratio 60% to 95%. In addition, the aperture ratio of a metal conductive layer means the area ratio which the opening part occupies in the projection area of the said metal conductive layer (area | region except it when there exists an outer frame). In the metal conductive layer, the line spacing (W ₂ ) is 50 to 1000 μm, preferably 100 to 400 μm. Thus, according to the present invention, the metal conductive layer can be accurately formed on the pretreatment layer having a fine pattern.

  In addition, as described in the description of the pretreatment layer, the metal conductive layer has the mesh-like pattern described above in the central portion on the transparent substrate, and a frame-like pattern in the peripheral portion excluding the central portion on the transparent substrate. It may have.

  The thickness of the metal conductive layer is 1 to 200 μm, preferably about 5 to 100 μm. If the thickness of the metal conductive layer is too thin, sufficient electromagnetic wave shielding properties may not be obtained. If the thickness is too thick, it is not preferable from the viewpoint of reducing the thickness of the light-transmitting electromagnetic wave shielding material.

  Next, in the method of the present invention, as shown in FIG. 1, the metal conductive layer 13 is blackened, and a blackened layer 14 is formed on at least a part of the surface of the metal conductive layer 13 (FIG. 1 arrow (A3)) may be further implemented.

  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.

  The thickness of the blackening treatment layer is not particularly limited, but is 0.01 to 1 μm, preferably 0.01 to 0.5 μm. If the thickness is less than 0.01 μm, the antiglare effect of light may not be sufficient, and if it exceeds 1 μm, the apparent aperture ratio when viewed from the perspective may be reduced.

  According to the above-described method of the present invention, a metal conductive layer having a fine pattern can be accurately produced by using an electroless plating pretreatment agent that does not contain particulate powder. It is possible to provide a light-transmitting electromagnetic wave shielding material that is excellent in shielding properties, appearance, and visibility.

The light-transmitting electromagnetic wave shielding material has a transparent substrate, a mesh-like pretreatment layer provided on the transparent substrate, a mesh-like metal conductive layer provided on the pretreatment layer,
The pretreatment layer has a configuration formed 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.

  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.

  The light-transmitting electromagnetic wave shielding material has a high light transmittance in the pretreatment layer by using an electroless plating pretreatment agent containing a predetermined component. Therefore, the light transmittance of the light-transmitting electromagnetic wave shielding material is not lowered by the formation of the pretreatment layer, and the light-transmitting electromagnetic wave shielding material is 75% or more, particularly 80 to 90% of the high total light. It has transmittance.

  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.

  In addition, since detailed description about each layer in 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 bonding a light-transmitting electromagnetic wave shielding material produced by the above method to a transparent substrate such as a glass plate via an adhesive layer or the like. In such a display filter, the openings of the mesh-shaped pretreatment layer and the metal conductive layer are filled with an adhesive layer.

  In addition to the transparent substrate, the electromagnetic wave shielding layer, and the adhesive layer, the electronic display filter may further include an antireflection layer, a color tone correction filter layer, a near infrared cut layer, and the like. The order of stacking these layers is determined according to the purpose. Further, the display filter may be provided with an electrode for connecting to the ground electrode of the PDP main body in order to enhance the electromagnetic wave shielding function.

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

(Example 1)
1. Preparation of pretreatment agent 5 wt% of the reaction product obtained by mixing imidazole with γ-glycidoxypropyltrimethoxysilane at a molar ratio of 1: 1 and reacting for 1 hour and 100 minutes. % Aqueous solution was added with stirring at 25 ° C. 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.

2. Next, the pretreatment agent is patterned on a PET film (thickness: 100 μm) by gravure printing, and then dried at 120 ° C. for 5 minutes to form a mesh on the PET film. A pretreatment layer was formed. In the pretreatment layer, the line width was 20 μm, the line interval was 235 μm, the aperture ratio was 85%, and the thickness was 0.15 μm.

3. Production of Metal Conductive Layer The PET film on which the pretreatment layer thus obtained was formed was immersed in an electroless copper plating solution (Melplate CU-5100 manufactured by Meltex Co., Ltd.) at 50 ° C. for 20 minutes. Then, electroless copper plating was performed to obtain a mesh-like metal conductive layer. In the metal conductive layer, the line width was 28 μm, the line interval was 227 μm, the aperture ratio was 79%, and the thickness was 4 μm.

4). Blackening treatment of metal conductive layer Furthermore, the blackening treatment 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 treatment conditions Bath temperature: about 60 ℃
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-transmitting electromagnetic wave shielding material was an average of 0.5 μm.

(Example 2)
A PET film on which a pretreatment layer produced in the same manner as in Example 1 was formed was immersed in an electroless copper plating solution (Melplate CU-5100, manufactured by Meltex Co., Ltd.) at 50 ° C. for 5 minutes. After performing the copper plating treatment, it was further immersed in an aqueous copper sulfate solution for electroplating, and a current of ² A / dm ² generated by a rectifier was applied for 5 minutes to obtain a mesh-like metal conductive layer. In the metal conductive layer, the line width was 28 μm, the line interval was 227 μm, the aperture ratio was 79%, and the thickness was 4 μm.

  Next, in the same manner as in Example 1, the metal conductive layer produced above was blackened to obtain a light-transmitting electromagnetic wave shielding material in which the surface of the metal conductive layer was blackened.

(Example 3)
The PET film on which the pretreatment layer produced in the same manner as in Example 1 was formed was immersed in an electroless nickel plating-boron alloy plating solution (Okuno Pharmaceutical Co., Ltd. Top Chemialloy B-1) at 60 ° C., 5 After the electroless copper plating treatment for 5 minutes, the mesh-shaped metal conductive layer is further immersed in an aqueous copper sulfate solution for electroplating and a current of ² A / dm ² generated by a rectifier is applied for 5 minutes. Obtained. In the metal conductive layer, the line width was 28 μm, the line interval was 227 μm, the aperture ratio was 79%, and the thickness was 4 μm.

  Next, in the same manner as in Example 1, the metal conductive layer produced above was blackened to obtain a light-transmitting electromagnetic wave shielding material in which the surface of the metal conductive layer was blackened.

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 a schematic diagram which shows an example of the pattern of a pre-processing layer.

Explanation of symbols

11 ... Transparent substrate,
12, 22 ... mesh-shaped pretreatment layer,
13 ... Mesh-like metal conductive layer,
14 ... blackening treatment layer,
25: Opening.

Claims (14)

By printing 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 in a mesh form on the transparent substrate, the mesh-like form is formed on the transparent substrate. A step of forming a pretreatment layer, and a step of forming a mesh-like metal conductive layer on the pretreatment layer by electroless plating,
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 light transmissive electromagnetic wave shielding material according to any one of claims 1 to 4, 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. Production method.   The method for producing a light-transmitting electromagnetic wave shielding material according to any one of claims 1 to 5, wherein the electroless plating pretreatment agent is printed on the transparent substrate in a mesh shape and then dried at 80 to 160 ° C.   The method for producing a light-transmitting electromagnetic wave shielding material according to any one of claims 1 to 6, wherein the plating metal by electroless plating is silver, copper, or aluminum.   The method for producing a light-transmitting electromagnetic wave shielding material according to any one of claims 1 to 7, further comprising performing electrolytic plating after performing the electroless plating.   The light-transmitting electromagnetic wave shield 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. A method of manufacturing the material.   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-transmitting electromagnetic wave shielding material manufactured by the manufacturing method of any one of Claims 1-10. A transparent substrate, a mesh-shaped pretreatment layer provided on the transparent substrate, and a mesh-shaped metal conductive layer provided on the pretreatment layer;
A light-transmitting electromagnetic wave shielding material, wherein the pretreatment layer is formed 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.   The light transmissive electromagnetic wave shielding material according to claim 12, further comprising a blackening treatment layer on at least a part of a surface of the metal conductive layer. A display filter comprising the light transmissive electromagnetic wave shielding material according to claim 12.

Images