JP2007096217A - Electromagnetic wave shielding plate, its production process, and display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic wave shielding material having high shielding power which can be produced inexpensively through a simple process and in which scattering of light does not take place on the interface of a substrate and an adhesive because no adhesive is used and a high light transmittance is ensured, and to provide its production process. <P>SOLUTION: The production process of an electromagnetic wave shielding material comprises a step for forming a substrate with a metal thin film using a metal thin film 4 and a resin substrate material 3 by a melting extrusion laminating method, and a step for patterning the metal thin film into mesh by etching and forming a meshed metal thin film. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a transparent electromagnetic wave shielding function which is used for a display surface of a display such as a CRT or a plasma display panel, and which has many functions, a manufacturing method thereof, and a display device using the same It is about.

  In recent years, electromagnetic noise interference (EMI) has been increased with the advancement of functions and increased use of electric and electronic devices, and it is known that they are also generated from displays such as CRT, PDP, liquid crystal, and EL. Among them, PDP is a combination of glass having an electrode and a fluorescent layer and glass having a transparent electrode, and generates a large amount of electromagnetic waves, near infrared rays, and heat when activated. Usually, in order to shield electromagnetic waves, a front plate including an electromagnetic wave shielding sheet is provided on the front surface of the PDP. In order to shield electromagnetic waves generated from the front surface of the display, a function of 30 dB or more at 30 MHz to 1 GHz is required. Further, near infrared rays having a wavelength of 800 to 1100 nm generated from the front of the display also cause other devices such as VTRs to malfunction, and thus need to be shielded. Furthermore, in order to make the display image easy to see, it is difficult to see the metal mesh part for shielding electromagnetic waves, the mesh pattern accuracy is good and the mesh is not disturbed, and the appropriate transparency (visible light transmittance, visible light transmission) ). Furthermore, the PDP is characterized by an increase in size, and the electromagnetic shielding material needs to have a large outer dimension accordingly. For this reason, the manufacturing method of the electromagnetic shielding sheet which shields electromagnetic waves, is excellent in transparency and mesh precision, has a good yield in a short process, and is inexpensive.

As a conventional method for producing an electromagnetic wave shielding material, there are a method of coating a mesh with an adhesive (Cited document 1) and a method of forming a mesh by pattern etching after laminating ingredients (Cited document 2). In this case, since the adhesive layer is used, the optical properties are degraded due to a decrease in the light transmittance of the entire electromagnetic wave shielding material due to the light transmittance of the adhesive itself, and light scattering that occurs at the interface between the adhesive and the substrate. There are things to do. In particular, such an electromagnetic wave shielding material is often used by providing another functional layer or an adhesive layer on the metal mesh. In that case, the electromagnetic wave shielding material is provided on the metal mesh with an adhesive for bonding the substrate and the metal mesh. Light scattering may also occur at the interface with the functional layer or adhesive layer. Therefore, it is necessary to consider the relationship between the light transmittance of the adhesive and the refractive index with the upper and lower layers, which is complicated.
Further, as a method not using an adhesive, a method of forming a mesh pattern by photolithography after plating a metal film on a base material (Cited document 3) and the like can be mentioned. However, in this method, the plating process takes time and labor, and the productivity is not so good.
Also, as a method that does not use an adhesive, a method of forming a conductive pattern by a printing method is also known, but it is sufficient due to insufficient conductivity of the conductive coating liquid and difficulty of thick film printing. It was difficult to obtain sufficient electrical conductivity, and it was difficult to obtain sufficient electromagnetic waves.
Japanese Patent Laid-Open No. 10-41682 JP-A-11-74687 Japanese Patent Laid-Open No. 2004-241761

  The present invention solves the above-mentioned conventional problems and does not use an adhesive, so there is no light scattering at the interface between the base material and the adhesive, it has a high light transmittance, and it is low-cost and simple. The present invention provides an electromagnetic wave shielding sheet that can be produced in a process and has high electromagnetic wave shielding ability.

  The invention according to claim 1 is an electromagnetic wave shielding material characterized in that a mesh-like metal thin film is directly provided on a resin substrate.

  The invention according to claim 2 is the electromagnetic wave shielding material according to claim 1, wherein the metal thin film is blackened.

  The invention according to claim 3 is the electromagnetic wave shielding material according to claim 1 or 2, wherein the metal thin film is a copper thin film.

  The invention according to claim 4 is the method for producing an electromagnetic wave shielding material according to any one of claims 1 to 3, wherein a coating layer is provided on the mesh-shaped metal thin film.

  The invention according to claim 5 is the method for producing an electromagnetic wave shielding material according to any one of claims 1 to 4, wherein an adhesive layer is provided on the mesh-like metal thin film.

  The invention according to claim 6 is the method for producing an electromagnetic wave shielding material according to claim 4 or 5, wherein a functional layer is provided on the mesh metal thin film via an adhesive layer or a coating layer. .

  According to a seventh aspect of the present invention, the functional layer has conductivity, antireflection, reflection reduction, hard coat, antiglare, antifouling function, near infrared absorption function, ultraviolet absorption function, color correction function, and heat dissipation function. The method for producing an electromagnetic wave shielding material according to claim 6, wherein the layer has one or more functions of shock resistance buffering function.

  The invention according to claim 8 includes any one or more of a near-infrared absorber, an ultraviolet absorber, and a color correction agent in the coating layer or the adhesive layer. This is a method for producing an electromagnetic shielding material.

  A ninth aspect of the present invention is a display device comprising the electromagnetic shielding material according to any one of the first to eighth aspects provided on a front surface.

  The invention of claim 10 is a step of forming a base material with a metal thin film by laminating a molten resin base material and a metal thin film by a melt extrusion laminating method, patterning the metal thin film into a mesh shape by an etching method, And a step of forming a mesh metal thin film.

  The invention of claim 11 is the method for producing an electromagnetic wave shielding material according to claim 10, wherein the metal thin film is blackened.

  The invention of claim 12 is the method for producing an electromagnetic wave shielding material according to claim 10 or 11, further comprising a step of blackening the metal thin film after forming the mesh metal thin film.

  The invention of claim 13 is the method for producing an electromagnetic wave shielding material according to any one of claims 10 to 12, wherein the metal thin film is a copper thin film.

  The invention according to claim 14 is the method for producing an electromagnetic wave shielding material according to any one of claims 10 to 13, further comprising a step of providing a coating layer on the mesh-shaped metal thin film.

  The invention of claim 15 is the method for producing an electromagnetic wave shielding material according to any one of claims 10 to 14, further comprising a step of providing an adhesive layer on the mesh-like metal thin film.

  The invention according to claim 16 includes the step of providing a functional layer on the mesh-like metal thin film via an adhesive layer or a coating layer, according to the method for producing an electromagnetic wave shielding material according to claim 14 or 15. is there.

  According to a seventeenth aspect of the present invention, the functional layer has conductivity, antireflection, reflection reduction, hard coat, antiglare, antifouling function, near infrared absorption function, ultraviolet absorption function, color correction function, and heat dissipation function. The method for producing an electromagnetic wave shielding material according to claim 16, wherein the layer has one or more functions of shock resistance buffering function.

  The invention according to claim 18 includes any one or more of a near-infrared absorber, an ultraviolet absorber, and a color correction agent in the coating layer or the adhesive layer. This is a method for producing an electromagnetic shielding material.

  According to the present invention, since no adhesive is used between the resin base material and the mesh-like metal thin film layer, it depends on the light transmittance of the adhesive itself, light scattering at the interface between the adhesive and other layers, or the like. It is possible to provide an electromagnetic wave shielding material that does not deteriorate optical characteristics. Further, there is no distortion associated with curing shrinkage of the adhesive.

  The present invention forms a laminate of a base material and a metal thin film by laminating a metal thin film and a resin base material by melt extrusion lamination, and then forming the metal thin film into a mesh shape using an etching method. An electromagnetic wave shielding material having a mesh-like metal thin film on a substrate is characterized.

The resin base material of the present invention may be any plastic film that can be applied to the melt extrusion lamination method and has flexibility after the base material is formed.
For example, engineering such as polyolefin resin such as polyethylene (PE) and polypropylene (PP), metal ionomer, acid-modified polyolefin resin, ethylene-methacrylic copolymer (EMAA), polyester resin, acrylic resin, polycarbonate (PC), etc. Mention may be made of plastics or super engineering plastics.
Further, in the present invention, the metal thin film is formed into a mesh shape using an etching method, and therefore, it is sufficient if it has heat resistance, etching resistance, acid resistance, and alkali resistance in consideration of the mesh formation process.
Specifically, mp is 30 to 300 ° C. (DSC), turbidity (HAZE) is 0.2 to 5.0 (JIS K-7105), and MFR is 0.5 to 50 g / min (JIS k-6760). It is preferable to use a resin that falls within the above range. If it is this range, the below-mentioned metal thin film and resin base material can be bonded together in a favorable adhesion state, and it will have high transparency.

The melt extrusion laminating method can be performed, for example, by a method as shown in a schematic diagram in FIG. In FIG. 1, the resin base material is sent from the resin base material tank 2 having the molten resin base material to the die head 1, and the resin base material discharged from the die head 1 is bonded to the metal thin film to be conveyed. By cooling accordingly, the resin base material hardens, and a laminate of the resin base material and the metal thin film can be obtained.
The resin base material can be brought into a molten state by, for example, supplying the resin base material in a pellet form to the resin base material tank and heating it.

  Various conditions such as the slit width and other shapes of the die head 1 and the conveyance speed of the metal thin film can be selected and set according to the type of resin, characteristics such as viscosity, and the film thickness of the resin base material.

In addition, a well-known additive can be added to a base material. Examples of the additive include a light stabilizer, an ultraviolet absorber, and an antistatic agent.
As the ultraviolet absorber, either an inorganic type or an organic type can be used, but an organic ultraviolet absorber is practical. Organic UV absorbers have maximum absorption between 300 and 400 nm, and absorb light in that region efficiently. Triazine UV absorbers, benzotriazole UV absorbers, benzophenone UV absorbers Agents, salicylic acid ester ultraviolet absorbers, acrylate ultraviolet absorbers, oxalic acid anilide ultraviolet absorbers, hindered amine ultraviolet absorbers, and the like. These may be used alone, but are more preferably used in combination of several kinds. Moreover, stabilization can be improved by blending the said ultraviolet absorber and a hindered amine light stabilizer, or antioxidant.
Antistatic agents include metal compounds such as antimony pentoxide, tin oxide, zinc oxide, and indium oxide, complex metal compounds such as antimony-containing complex oxides, In-Sn complex oxides, and phosphorus compounds, and quaternary ammonium. Salts, amine derivatives such as amine oxide, and conductive polymers such as polyaniline can be used.
These additives may be added at a stage where the resin is in a pellet form or in a molten state.

  The thickness of the resin substrate is preferably about 5 to 500 μm. When the thickness is less than 5 μm, the handleability is deteriorated, and when it exceeds 500 μm, the flexibility is lost and the handleability is deteriorated.

  A well-known method can be used for patterning into a mesh shape using an etching method of a metal thin film.

As the metal thin film, a thin film made of a metal such as copper, aluminum, nickel, iron, gold, silver, stainless steel, tungsten, chromium, titanium, or a thin film made of an alloy in which two or more of them are combined can be used. Copper, aluminum, and nickel thin films are preferred from the viewpoints of conductivity (electromagnetic wave shielding properties), ease of forming a mesh pattern, and cost. In addition, a thin film made of a paramagnetic metal such as nickel, iron, stainless steel, or titanium is preferable because it has excellent magnetic shielding properties.
The thickness of the metal thin film is preferably in the range of 0.5 to 40 μm. If it exceeds 40 μm, it becomes difficult to form fine lines and the viewing angle becomes narrow. On the other hand, when the thickness is less than 0.5 μm, the surface resistance increases and the electromagnetic wave shielding effect tends to be inferior. From the viewpoint of electromagnetic wave shielding properties, 1 to 20 μm is more preferable.

When the electromagnetic wave shielding material of the present invention is used for a display application, a metal thin film that has been blackened in advance may be used, or blackening treatment may be performed after a mesh-shaped electromagnetic wave shielding layer is formed. When the blackening treatment is performed later, the side surfaces of the mesh-shaped electromagnetic wave shielding layer can be blackened simultaneously, which is preferable. Further, it is preferable to use a metal thin film that has been blackened in advance and then blacken it again after forming a mesh shape, because the entire surface can be blackened.
When the blackening process is performed, the contrast of the display can be improved.

The mesh-shaped electromagnetic shielding layer is formed by forming a mesh-like etching resist pattern on the surface of the metal thin film using a microlithographic method, screen printing method, intaglio offset printing method, etc. This can be performed by selectively etching the metal thin film using an etching solution having the same.
Examples of the microlithographic method used for forming the etching resist pattern include a photolithographic method, an X-ray lithographic method, an electron beam lithographic method, and an ion beam lithographic method. Among these, the photolithographic method is the most efficient in terms of its simplicity and mass productivity. Among these, the photolithographic method using chemical etching is most preferable from the viewpoints of simplicity, economy, and metal mesh processing accuracy.
In the photolithography method, either negative type or positive type etching resist can be used. The etching resist ink is not particularly limited as long as the cured product has resistance to a metal etching process, and generally known photoresist compositions, photosensitive resin compositions, and thermosetting resin compositions are used. is there.

  As a method for etching a metal thin film, there is a chemical etching method. The chemical etching method is a method in which a metal thin film other than a portion protected by an etching resist is dissolved with an etching solution and removed. Examples of the etching solution include a ferric chloride aqueous solution, a cupric chloride aqueous solution, and an alkaline etching solution. Among these, aqueous solutions of ferric chloride and cupric chloride that are low-contamination and can be reused are preferable. The concentration of the etching solution is usually about 150 to 250 g / liter, although it depends on the thickness of the metal thin film and the processing speed. The liquid temperature is preferably in the range of 40 to 80 ° C. Methods for exposing a metal thin film to an etchant include immersion of the metal thin film in the etchant, showering of the etchant into the metal thin film, and exposure of the metal thin film to the gas phase of the etchant. From the viewpoint of stability, showering of the etching solution onto the metal thin film is preferable.

  The unit shapes composing the mesh-shaped electromagnetic wave shielding layer include triangles such as regular triangles, isosceles triangles, right triangles, squares, rectangles, rhombuses, parallelograms, trapezoids, etc., hexagons, octagons, twelve Examples thereof include n-gons such as a square and an icosahedron (n is a positive number), a circle, an ellipse, and a star. The shape of the mesh is composed of one or more combinations of the unit shapes. As the unit shape constituting the mesh, a triangle is most effective from the viewpoint of electromagnetic shielding properties, but from the viewpoint of visible light transmittance, it is preferable that n of the n-gon is larger.

  Further, it is preferable that the width of the lines constituting the mesh shape is 40 μm or less, the line interval is 100 μm or more, and the line thickness is 40 μm or less. Further, from the viewpoint of invisibility, the line width is more preferably 25 μm or less, the line interval is 120 μm or more and the line thickness is 18 μm or less from the viewpoint of visible light transmittance. The line width is preferably 40 μm or less, particularly 25 μm or less, and if it is too small or thin, the surface resistance becomes too large and the shielding effect is poor, so that it is preferably 1 μm or more. The thickness of the line is preferably 40 μm or less, and if the thickness is too thin, the surface resistance becomes too large and the shielding effect is poor, so 0.5 μm or more is preferable and 1 μm or more is more preferable. The larger the line interval, the better the aperture ratio and the visible light transmittance. As described above, when used on the front surface of the display, the aperture ratio is preferably 50% or more, more preferably 60% or more. When the line interval becomes too large, the electromagnetic wave shielding property is lowered. Therefore, the line interval is preferably 1000 μm (1 mm) or less. Here, the aperture ratio is a percentage of the ratio of the area obtained by subtracting the area of the electromagnetic wave shielding layer from the effective area to the effective area of the electromagnetic wave shielding layer.

The blackening treatment of the surface of the metal thin film or mesh-shaped electromagnetic wave shielding layer can be performed using a blackening treatment liquid by a method performed in the printed wiring board field. The upper surface and the lateral surface of the mesh-shaped electromagnetic wave shielding layer surface are blackened.
The blackening treatment is performed, for example, by treating at 95 ° C. for 2 minutes in an aqueous solution of sodium chlorite (31 g / liter), sodium hydroxide (15 g / liter), and trisodium phosphate (12 g / liter). Can do.

By providing a coating layer in the opening of the mesh metal thin film of the electromagnetic wave shielding material of the present invention, the opening can be filled and flattened.
As the coating layer, acrylic, polyester, polycarbonate, polyurethane, polyolefin, polyimide, polyamide, polystyrene, cycloolefin, polyarylate, polysulfone, or other resins can be used.
The forming method can be formed by applying a coating liquid containing these materials. As a coating method, a known method can be used. For example, a method using a rod or a wire bar, a coating method such as a micro gravure, a gravure, a die, a curtain, a lip, or a slot, a calendar method, or a casting method. Can be used.

  In addition, an adhesive or adhesive layer can be provided in the opening of the mesh metal thin film of the electromagnetic wave shielding material instead of the coating layer. By providing an adhesion or pressure-sensitive adhesive layer, it is possible to improve the adhesion with other functional layers described later, and it can be attached to an object such as a display.

  As the adhesive or pressure-sensitive adhesive, general ones can be used, for example, acrylic resins, epoxy resins, urethane resins, polyester resins, polyether resins, engineering plastics, super engineering plastics, urea resins. Melamine resin, copolymer resin, acetate resin, silicon resin, silica resin, vinyl acetate resin, polystyrene resin, cellulose resin, polyolefin resin, etc., if possible, the surface is smooth Higher transparency is preferred.

  Moreover, the coating layer, the adhesive layer, or the adhesive layer can contain a material having functions such as a near infrared absorption function, a color correction function, and an ultraviolet absorption function described later.

Another functional layer can be laminated on the electromagnetic wave shielding material of the present invention.
As functional layers, any of conductivity, antireflection, reflection reduction, hard coat, antiglare, antifouling function, near infrared absorption function, ultraviolet absorption function, color correction function, heat dissipation function, shock resistance buffer function Or a layer having one or more functions.

The functional layer may be provided on the coating layer, may be provided on the adhesion or pressure-sensitive adhesive layer, or may be provided on the coating layer via adhesion or pressure-sensitive adhesive. Moreover, you may provide directly or through adhesion | attachment or an adhesive on the opposite side to the side which provides the mesh-shaped metal thin film layer of a resin base material.
Moreover, when a functional layer is a multiple layer, you may laminate | stack on one side of an electromagnetic wave shielding material, and may laminate | stack on both surfaces.

  The layer having a hard coat function is to prevent the surface of the plasma display from being scratched, and an ultraviolet curable resin, an electron beam curable resin, a thermosetting resin, or the like can be used. Not receive. For example, it can be formed with various (meth) acrylates, a photopolymerization initiator, and, if necessary, a coating agent containing an organic solvent as a main component. As various (meth) acrylates, (meth) acrylates such as polyurethane (meth) acrylate and epoxy (meth) acrylate, or other polyfunctional (meth) acrylates can be preferably used.

  Epoxy (meth) acrylate is obtained by esterifying an epoxy group of an epoxy resin with (meth) acrylic acid and converting the functional group to a (meth) acryloyl group, and a (meth) acrylic acid adduct to a bisphenol A type epoxy resin, There are (meth) acrylic acid adducts to novolac type epoxy resins.

The urethane (meth) acrylate can be obtained, for example, by reacting an isocyanate group-containing urethane prepolymer obtained by reacting a polyol and a polyisocyanate under an excess of isocyanate groups with (meth) acrylates having a hydroxyl group. . Alternatively, a hydroxyl group-containing urethane prepolymer obtained by reacting a polyol and a polyisocyanate under hydroxyl-excess conditions can be obtained by reacting with a (meth) acrylate having an isocyanate group.
Examples of polyols include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, butylene glycol, 1,6-hexanediol, 3-methyl-1,5-pentane glycol, neopentyl glycol, hexanetriol, trimellilol propane, polytetra Examples include methylene glycol and a condensation polymer of adipic acid and ethylene glycol.
Examples of the polyisocyanate include tolylene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate.
Examples of (meth) acrylates having a hydroxyl group include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, pentaerythritol triacrylate, and dipentaerythritol pentaacrylate.
Examples of (meth) acrylates having an isocyanate group include 2-methacryloyloxyethyl isocyanate and methacryloyl isocyanate.

  Other polyfunctional (meth) acrylates have two or more (meth) acryloyl groups in the molecule, and preferably have three or more acryloyl groups in the molecule. Specifically, trimethylolpropane triacrylate, ethylene oxide-modified trimethylolpropane triacrylate, propylene oxide-modified trimethylolpropane triacrylate, tris (acryloyloxyethyl) isocyanurate, caprolactone-modified tris (acryloyloxyethyl) isocyanurate, pentaerythritol Triacrylate, pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, alkyl modified dipentaerythritol triacrylate, alkyl modified dipentaerythritol pentaacrylate, caprolactone modified dipentaerythritol hexaacrylate, Beauty mixtures of two or more of these and the like.

  As photopolymerization initiators, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, diethoxyacetophenone, gendyl dimethyl ketal, 2-hydroxy-2-methylpropiophenone, 1-hydroxycyclohexyl phenyl ketone, benzophenone 2,4,6-trimethylbenzoin diphenylphosphine oxide, Michler's ketone, isoamyl N, N-dimethylaminobenzoate, 2-chlorothioxanthone, 2,4-diethylthioxanthone, and the like. The above can also be used together as appropriate.

  Organic solvents include aromatic hydrocarbons such as toluene and xylene, esters such as ethyl acetate, acetic acid-n-propyl, acetic acid-iso-propyl, acetic acid-n-butyl, acetic acid-iso-butyl, methyl Alcohols such as alcohol, ethyl alcohol, n-propyl alcohol, iso-propyl alcohol, n-butyl alcohol, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone cyclohexanone, 2-methoxyethanol, 2-ethoxyethanol, 2-butyl Tokiethanol, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, propylene glycol methyl ether and other ethers, 2-methoxyethyl acetate, 2-ethoxyethyl acetate DOO, 2-butoxyethyl acetate, ether esters such as propylene glycol methyl ether acetate and the like, can also be used as a mixture of two or more thereof.

  In addition to the above components, a colloidal metal oxide or silica sol using an organic solvent as a dispersion medium may be added to improve wear resistance.

Moreover, a hard-coat layer is obtained by applying the said coating liquid.
As the coating method, methods such as bar coating, blade coating, spin coating, reverse coating, diting, spray coating, roll coating, gravure coating, lip coating, air knife coating, and dipping method can be used.

After the coating liquid is applied, the solvent is dried and the coating agent is crosslinked and cured. If the coating agent is an active energy ray curable type such as an ultraviolet ray or an electron beam, the crosslinking can be cured by irradiating the active energy ray.
Active energy rays include ultraviolet rays emitted from light sources such as xenon lamps, low-pressure mercury lamps, high-pressure mercury lamps, ultra-high pressure mercury lamps, metal halide lamps, carbon arc lamps, tungsten lamps, or electron beams extracted from electron beam accelerators usually 20 to 2000 KeV. , Α rays, β rays, γ rays and the like can be used. The scratch-preventing layer thus formed has a thickness of usually 1 to 50 μm, preferably 3 to 20 μm.
Further, when a thermosetting material is used, it can be cured by an overheating process.

The layer having an antireflection or reflection reducing function prevents surface reflection and increases the visible light transmittance, and any processing method can be selected as the formation method, and there is no particular limitation.
For example, a method in which a low-refractive index thin film layer or a multilayer thin film having a different refractive index is formed on one side or both sides of a support, and the reflectivity is reduced by interference of light reflected on the surface of the thin film and refracted reflected light at the interface. Is common.

  As the antireflection or reflection reduction layer, an optical layer single layer or a combination thereof can be used. Specific examples of the layer structure include a low refractive index layer single layer having a refractive index of 1.2 to 1.45, a refractive layer. An alternating combination of a high refractive index layer and a low refractive index layer having a refractive index of 1.7 to 2.4, a medium refractive index layer and a refractive index of 1.7 to 2.4 with a refractive index of 1.5 to 1.9. And a combination of a high refractive index layer and a low refractive index layer.

As the low refractive index layer, metal compounds such as MgF ₂ (refractive index: about 1.4), SiO ₂ (refractive index: about 1.2 to 1.5), LiF (refractive index: about 1.4), A composite metal compound such as 3NaF · AlF ₃ (refractive index: about 1.4) or Na ₃ AlF ₆ (refractive index: about 1.33) can be used.
As the middle refractive index layer, a metal compound such as Al ₂ O ₃ (refractive index: about 1.65), MgO (refractive index: about 1.63), or an Al—Zr composite oxide (refractive index: about 1.7). A composite metal compound such as ˜1.85) can be used.
As the high refractive index layer, TiO ₂ (refractive index: about 2.3), ZrO ₂ (refractive index: about 2.05), Nb ₂ O ₅ (refractive index: about 2.25), Ta ₂ O ₅ ( Metal compounds such as refractive index: about 2.15) and CeO (refractive index: about 2.15) and composite metal compounds such as In-Sn composite oxide (refractive index: about 1.7 to 1.85) are used. be able to.

  These optical layers can be formed using a known method such as a vacuum deposition method, a sputtering method, a chemical vapor deposition method (CVD method), a reactive sputtering method, an ion plating method, an electroplating method, or the like.

Further, particles in which particles made of the above-described metal compound or composite metal compound are dispersed in a matrix may be used.
In particular, as the low refractive index layer, a material in which low refractive fine particles such as MgF ₂ and SiO ₂ are dispersed in ultraviolet and electron beam curable resin or silicon alkoxide matrix can be used. The low refractive fine particles are preferably porous because the refractive index becomes lower.
When the low refractive index layer is formed of a matrix containing the low refractive fine particles, the low refractive index fine particles are coated so that the film thickness is 0.01 to 1 μm, and if necessary, a drying treatment, It can be formed by performing ultraviolet irradiation treatment or electron beam irradiation treatment.

When an optical layer using particles and a matrix is used, it can be formed by a coating method.
As a coating method, a known method can be used. For example, a method using a rod or a wire bar, or various coating methods such as a micro gravure, a gravure, a die, a curtain, a lip, or a slot can be used.

The layer having an antiglare function reduces luminous reflectance by irregularly reflecting external light and prevents glare.
For example, what consists of the layer containing a resin binder and microparticles | fine-particles is mentioned.
As the particles, fine particles having a particle diameter of about 0.1 to 10 μm such as silicon dioxide, acrylic, urethane, melamine and the like can be used.
As the resin binder, an acrylic resin or the like can be used.
The forming method can be performed by applying a coating liquid containing resin, particles, solvent and the like. As a coating method, a known method can be used. For example, a method using a rod or a wire bar, or various coating methods such as a micro gravure, a gravure, a die, a curtain, a lip, or a slot can be used.
Moreover, what embossed a resin binder may be used.
Further, these particles may be mixed in the hard coat layer or embossed on the surface of the hard coat layer.

As the layer having an antistatic function, a known material can be used, and examples thereof include a layer formed by mixing a conductive antistatic agent in a resin or a silica binder.
As the resin binder, an acrylic binder can be used publicly. The silica binder may be those obtained by the silicon alkoxide represented by R x _Si (OR) _y, an organic silicon alkoxide is hydrolyzed.
Examples of the conductive antistatic agent include metal compounds such as antimony pentoxide, tin oxide, zinc oxide, and indium oxide, complex metal compounds such as antimony-containing complex oxide, In-Sn complex oxide, and phosphorus compound, Quaternary ammonium salts, amine derivatives such as amine oxide, and conductive polymers such as polyaniline can be used.
The forming method can be formed by applying a resin or a coating liquid containing these materials. As a coating method, a known method can be used. For example, a method using a rod or a wire bar, a coating method such as a micro gravure, a gravure, a die, a curtain, a lip, or a slot, a calendar method, or a casting method. Can be used.
Note that these antistatic materials may be used in the hard coat layer or the antiglare layer.

The layer having an antifouling function is a layer for preventing surface contamination and is provided on the outermost surface. As the antifouling layer, an antifouling material such as a fluorine-based, silicon-based compound or fluorine-containing silicon compound can be formed by a vapor phase method such as a vapor deposition method or a chemical vapor deposition method (CVD method). Further, these materials can be formed by using a dipping method, a method using a rod and a wire bar, various coating methods such as microgravure, gravure, die, curtain, lip, and slot, a calendar method, and a casting method.
Moreover, you may mix these materials in the other functional layer of the outermost surface. For example, an antifouling function may be provided by mixing in a binder of an antireflection layer or an antiglare layer.

The layer having a near infrared absorption function may be any layer having a high transmittance in the wavelength region of 400 to 800 nm and a low transmittance in the wavelength region of 800 to 1200 nm.
As the near-infrared absorbing layer, for example, a near-infrared absorbing thin film such as a resin binder mixed with a near-infrared absorbing dye or pigment or an In-Sn composite oxide can be used.
Examples of such near infrared absorbers include diimonium-based, phthalocyanine-based, dithiol metal complex-based, cyanine-based, metal complex-based, metal fine powder, metal oxide fine powder, and combinations including resins are free, The antagonistic action and synergistic action should be identified and used appropriately.

As the diimonium compound, for example, one represented by the following formula (1) can be selected.
The diimonium compound represented by the above formula (1) has a large blocking in the near infrared region, a wide blocking region, and a high transmittance in the visible region.

Specific examples of R1 to R8 in the formula (1) are the same or different and are a hydrogen atom, a substituted or unsubstituted alkyl group, a halogenalkyl group, a cyanoalkyl group, an aryl group, an alkenyl group, an aralkyl group, An alkynyl group, a hydroxyl group, a phenyl group, and a phenylalkylene group, and ring A and ring B may have a substituent.
Fluorine, chlorine and bromine as halogen atoms, methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, t-butyl group and n-amyl group as alkyl groups N-hexyl group, n-octyl group, 2-hydroxyethyl group, 2-cyanoethyl group, 3-hydroxypropyl group, 3-cyanopropyl group, methoxyethyl group, ethoxyethyl group, butoxyethyl group, etc. are alkoxy groups. As methoxy group, ethoxy group, propoxy group, butoxy group, etc. as aryl group, phenyl group, fluorophenyl group, chlorophenyl group, tolyl group, diethylaminophenyl, naphthyl group, etc., as aralkyl group as benzyl group, p -Fluorobenzyl group, p-chlorophenyl group, phenylpropyl group, naphthyl ester Etc. Le group, examples of the amino group include a dimethylamino group, a diethylamino group, dipropylamino group, dibutylamino group and the like.
X- is fluorine ion, chlorine ion, bromine ion, iodine ion, perchlorate ion, hexafluoroantimonate ion, hexafluorophosphate ion, tetrafluoroborate ion, tetraphenyl represented by the following formula (2) A borate ion (ring C may have a substituent), or a sulfonimide represented by the following formula (3) (R13 and R14 may be the same or different, and each is a fluoroalkyl group; Or a fluoroalkylene group formed by combining them). However, the present invention is not limited to those mentioned above. Some of these are available as commercial products, and for example, KayasorbIRG-068 manufactured by Nippon Kayaku Co., Ltd., CIR-RL manufactured by Nippon Carlit Co., Ltd., and the like can be suitably used.

  As the dithiol-based compound, a compound represented by the following formula (4) can be preferably used.

Specific examples of R9 to R12 in the formula (4) include halogen atoms such as fluorine, chlorine and bromine, methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso- Butyl group, t-butyl group, n-amyl group, n-hexyl group, n-octyl group, 2-hydroxyethyl group, 2-cyanoethyl group, 3-hydroxypropyl group, 3-cyanopropyl group, methoxyethyl group, Alkyl groups such as ethoxyethyl group and butoxyethyl group, alkoxy groups such as methoxy group, ethoxy group, propoxy group and butoxy group, aryl groups such as phenyl group, fluorophenyl group, chlorophenyl group, tolyl group, diethylaminophenyl and naphthyl group Benzyl group, p-fluorobenzyl group, p-chlorophenyl group, phenylpropyl group, naphthylethyl Aralkyl groups such as a group, dimethylamino group, diethylamino group, dipropylamino group, an amino group, such as a dibutylamino group.
As a commercial product, MIR-101 manufactured by Midori Chemical Co., Ltd. can be suitably used.
The said near-infrared shielding agent is an example, and is not limited to these.

  Examples of the phthalocyanine compounds include Excolor IR-1, IR-2, IR-3, IR-4, TXEX-805K, TXEX-809K, TXEX-810K, TXEX-811K, and TXEX-812K manufactured by Nippon Shokubai Co., Ltd. Etc. can be used suitably. The said near-infrared shielding agent is an example, and is not limited to these.

  As the cyanine compound, for example, CY17 manufactured by Nippon Kayaku Co., Ltd., SD50 manufactured by Sumitomo Seika Co., Ltd., NK-5706 manufactured by Hayashibara Biochemical Laboratories Co., Ltd., and the like can be preferably used. The said near-infrared shielding agent is an example, and is not limited to these.

In addition, as the resin binder, acrylic, polyester, polycarbonate, polyurethane, polyolefin, polyimide, polyamide, polystyrene, cycloolefin, polyarylate, polysulfone, or other resins can be used.
The forming method can be formed by applying a coating liquid containing these materials. As a coating method, a known method can be used. For example, a method using a rod or a wire bar, a coating method such as a micro gravure, a gravure, a die, a curtain, a lip, or a slot, a calendar method, or a casting method. Can be used.
Moreover, you may mix and use a near-infrared absorber in the said hard-coat layer, a glare-proof layer, an antistatic layer, etc.

The layer having an ultraviolet absorption function is capable of efficiently absorbing ultraviolet rays having a wavelength of 400 nm or less, and preferably capable of absorbing 80% or more of a wavelength of 350 nm. Examples of the ultraviolet absorbing layer include those in which an ultraviolet absorber is mixed in a resin binder.
As the resin binder, acrylic, polyester, polycarbonate, polyurethane, polyolefin, polyimide, polyamide, polystyrene, cycloolefin, polyarylate, polysulfone, and the like can be used.
As the ultraviolet absorber, either an inorganic type or an organic type can be used, but an organic ultraviolet absorber is practical. Organic UV absorbers have maximum absorption between 300 and 400 nm, and absorb light in that region efficiently. Triazine UV absorbers, benzotriazole UV absorbers, benzophenone UV absorbers Agents, salicylic acid ester ultraviolet absorbers, acrylate ultraviolet absorbers, oxalic acid anilide ultraviolet absorbers, hindered amine ultraviolet absorbers, and the like. These may be used alone, but are more preferably used in combination of several kinds. Moreover, stabilization can be improved by blending the said ultraviolet absorber and a hindered amine light stabilizer, or antioxidant. Moreover, it can also substitute for an ultraviolet absorber layer by using a plastic film containing an ultraviolet absorber (kneading etc.) as a base material.
The forming method can be formed by applying a coating liquid containing these materials. As a coating method, a known method can be used. For example, a method using a rod or a wire bar, a coating method such as a micro gravure, a gravure, a die, a curtain, a lip, or a slot, a calendar method, or a casting method. Can be used.
Further, an ultraviolet absorber may be mixed into the hard coat layer, the antiglare layer, the antistatic layer and the like. Moreover, you may mix both a near-infrared absorber and a ultraviolet absorber.

The layer having a color correction function is for correcting the color balance of the display color, and examples thereof include a layer for cutting orange light having a wavelength of 580 to 610 nm emitted from neon or the like in a plasma display.
As the resin binder, acrylic, polyester, polycarbonate, polyurethane, polyolefin, polyimide, polyamide, polystyrene, cycloolefin, polyarylate, polysulfone, and the like can be used.
Various dyes for color correction can be used depending on the application, but cyanine (polymethine), quinone, azo, indigo, polyene, spiro, porphyrin, phthalocyanine, naphthalocyanine, Examples thereof include cyanine-based pigments, but are not limited thereto. Further, for the purpose of cutting orange light having a wavelength of 580 to 610 nm emitted from neon or the like in a plasma display, cyanine, porphyrin, pyromethene, or the like can be used.
The forming method can be formed by applying a coating liquid containing these materials. As a coating method, a known method can be used. For example, a method using a rod or a wire bar, a coating method such as a micro gravure, a gravure, a die, a curtain, a lip, or a slot, a calendar method, or a casting method. Can be used.
In addition, a color correction pigment may be mixed in the hard coat layer, the antiglare layer, the antistatic layer, or the like. Moreover, you may mix both a near-infrared absorber and a ultraviolet absorber.

In the present invention, a layer having a neutral gray ND filter function may be provided.
The ND filter layer may be any layer as long as the transmittance is generally 40 to 80%, and a known material can be formed using a known method.
In a display device using a fluorescent material such as a plasma display, a CRT, a fluorescent display tube, or a field emission display, the applied fluorescent material is irradiated with an electron beam or ultraviolet light to cause the fluorescent material to emit light and transmit or reflect the fluorescent screen. Display is performed with the light. Since phosphors are generally white and have high reflectance, external light is often reflected on the phosphor screen. For this reason, the problem of a decrease in display contrast due to reflection of external light becomes a problem in a display device using a phosphor, but can be reduced by providing an ND filter layer.

  In addition, a layer having a heat dissipation function, an impact resistance function, or the like can be stacked as the functional layer.

The electromagnetic wave shielding plate obtained in the present invention can be used as a display front or window film. In particular, it can be suitably used as a front plate of a plasma display.
When used as a front plate of a plasma display, it can be installed by sticking the electromagnetic shielding layer side directly to the front surface of the main body of the plasma display. At this time, bonding may be performed using an adhesive or a pressure-sensitive adhesive, and when the electromagnetic wave shielding layer is embedded in the adhesive or pressure-sensitive adhesive, the bonding may be performed using the bonding or pressure-sensitive adhesive.

  In addition, when the obtained electromagnetic shielding material is provided with an adhesive or a pressure-sensitive adhesive and directly attached to the plasma display, an additive may be added to the adhesive or the pressure-sensitive adhesive. Examples of the additive include materials having functions such as a near infrared absorption function, a color correction function, and an ultraviolet absorption function.

  The electromagnetic wave shielding layer is preferably grounded through the conducting portion. Specifically, an electromagnetic wave shielding mesh corresponding to the size of the display is created, and its end is made into a frame shape in order to give physical strength to the electromagnetic wave shielding layer. And it is preferable to make conduction | electrical_connection from a part of the edge part, and to ensure electromagnetic shielding property.

Extrusion lamination with maleic acid-modified PP resin (Admer QE851: made by Mitsui Chemicals, Inc.) was performed on an electrolytic copper foil having a thickness of 10 μm (manufactured by Nippon Electrolytic Co., Ltd .: PBR-10A). The temperature conditions were as follows: die temperature: 330 ° C., extrusion at a line speed of 30 m / min and a thickness of 100 μm, a mirror cooling roll was used, cooling film formation, and lamination with a copper foil were performed.
A dry film resist (Sunfort AQ1558: manufactured by Asahi Kasei Electronics Co., Ltd.) is laminated to the resin film with copper foil thus obtained using a 110 ° C. hot roll, and the geometric pattern is further exposed to a UV exposure machine. Developed using about 50 mJ / cm ² exposure and 3% aqueous sodium carbonate solution. Furthermore, the copper foil was etched using a ferric chloride solution having a liquid temperature of 50 ° C. and a specific gravity of 1.50 to obtain a geometric figure. Thereafter, the cured resist was peeled off with a 5% aqueous sodium hydroxide solution and washed with water. Thereafter, in order to blacken the copper portion on the surface, the copper lattice portion was blackened with an alkaline aqueous solution containing an oxidizing agent, and an electromagnetic shielding material having a desired geometric figure was created.

<Comparative example>
Using a polyol / polyisocyanate two-component curable adhesive to a 10 μm thick electrolytic copper foil (manufactured by Nippon Electrode Co., Ltd .: PBR-10A), a 100 μm thick PET base material was bonded, aged and adhered. . At this time, electrolytic copper foil was used for copper foil, and A4300 (manufactured by Toyobo Co., Ltd.) was used for PET. A dry film resist (Sunfort AQ1558: manufactured by Asahi Kasei Electronics Co., Ltd.) is laminated to the resin film with copper foil thus obtained using a 110 ° C. hot roll, and the geometric pattern is further exposed to a UV exposure machine. Developed using about 50 mJ / cm ² exposure and 3% aqueous sodium carbonate solution. Furthermore, the copper foil was etched using a ferric chloride solution having a liquid temperature of 50 ° C. and a specific gravity of 1.50 to obtain a geometric figure. Thereafter, the cured resist was peeled off with a 5% aqueous sodium hydroxide solution and washed with water. Thereafter, in order to blacken the copper portion on the surface, the copper lattice portion was blackened with an alkaline aqueous solution containing an oxidizing agent, and an electromagnetic shielding material having a desired geometric figure was created.

<Evaluation>
Number of layers: The number of layers such as a mesh metal layer, an adhesive layer, and a base material layer was compared.
Total light transmittance: The produced electromagnetic wave shielding material was measured using a turbidimeter (manufactured by Nippon Denshoku Industries Co., Ltd.).
Haze: The produced electromagnetic shielding material was produced using a turbidimeter (manufactured by Nippon Denshoku Industries Co., Ltd.).

  From Table 1, the electromagnetic wave shielding material of the example has a smaller number of layers than the comparative example and has high transparency.

It is the schematic which showed an example of the method of manufacturing the laminated body which consists of a metal thin film and resin base material in the electromagnetic wave shielding material of this invention by the melt-extrusion lamination method. It is the schematic which showed an example of a part of manufacturing process of the electromagnetic wave shielding material of this invention.

Explanation of symbols

1 Die head 2 Resin base material tank 3 Resin (molten)
3 'resin base material 4 metal foil 4' mesh shape metal foil

Claims (18)

  An electromagnetic wave shielding material, wherein a mesh-like metal thin film is directly provided on a resin substrate.   The electromagnetic shielding material according to claim 1, wherein the metal thin film is blackened.   The electromagnetic shielding material according to claim 1, wherein the metal thin film is a copper thin film.   The method for producing an electromagnetic wave shielding material according to claim 1, wherein a coating layer is provided on the mesh-shaped metal thin film.   The method for producing an electromagnetic wave shielding material according to claim 1, wherein an adhesive layer is provided on the mesh metal thin film.   The method for producing an electromagnetic wave shielding material according to claim 4 or 5, wherein a functional layer is provided on the mesh-shaped metal thin film via an adhesive layer or a coating layer.   The functional layer is one of conductivity, antireflection, reflection reduction, hard coat, antiglare, antifouling function, near infrared absorption function, ultraviolet absorption function, color correction function, heat dissipation function, and shock resistance buffer function. The method for producing an electromagnetic wave shielding material according to claim 6, wherein the layer has one or more functions.   The method for producing an electromagnetic wave shielding material according to any one of claims 4 to 7, wherein the coating layer or the adhesive layer contains one or more of a near-infrared absorber, an ultraviolet absorber, and a color correction agent. .   A display device comprising the electromagnetic wave shielding material according to claim 1 on a front surface.   A step of forming a substrate with a metal thin film by laminating a molten resin base material and a metal thin film by a melt extrusion lamination method, patterning the metal thin film into a mesh shape by an etching method, and forming a mesh metal thin film A process for producing an electromagnetic wave shielding material.   The method for producing an electromagnetic wave shielding material according to claim 10, wherein the metal thin film is blackened.   The method for producing an electromagnetic wave shielding material according to claim 10 or 11, further comprising a step of blackening the metal thin film after forming the mesh metal thin film.   The method for producing an electromagnetic wave shielding material according to claim 10, wherein the metal thin film is a copper thin film.   The method for producing an electromagnetic wave shielding material according to claim 10, further comprising a step of providing a coating layer on the mesh-like metal thin film.   The method for producing an electromagnetic wave shielding material according to claim 10, further comprising a step of providing an adhesive layer on the mesh-like metal thin film.   16. The method for producing an electromagnetic wave shielding material according to claim 14, further comprising a step of providing a functional layer on the mesh metal thin film via an adhesive layer or a coating layer.   The functional layer is one of conductivity, antireflection, reflection reduction, hard coat, antiglare, antifouling function, near infrared absorption function, ultraviolet absorption function, color correction function, heat dissipation function, and shock resistance buffer function. The method for producing an electromagnetic shielding material according to claim 16, wherein the layer has one or more functions.   The method for producing an electromagnetic wave shielding material according to any one of claims 14 to 17, wherein the coating layer or the adhesive layer contains at least one of a near infrared absorber, an ultraviolet absorber, and a color correction agent. .

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