JP2006210572A - Member for shielding electromagnetic waves - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a member for shielding electromagnetic waves having high light transmission properties and image definition. <P>SOLUTION: When manufacturing the member for shielding electromagnetic waves in which a mesh-like metal layer is formed on a transparent base 1 and a number of light-transmitting sections are demarcated, the mesh-like metal layer and a number of light-transmitting sections are covered with a curing paint film 15 of a transparent resin, and the average inclination angle of a raised section formed on a thin-line section 10a in the mesh-like metal layer in the curing paint film 15 is set to 10° or smaller. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electromagnetic wave shielding member, and more particularly to an electromagnetic wave shielding member having high light transmittance.

  Today, various electronic devices have become a necessity. During the operation of these electronic devices, electromagnetic waves are always radiated to a certain degree, and if the intensity is high, peripheral electronic devices may malfunction or cause adverse effects on the human body. For this reason, various electromagnetic shielding materials or electromagnetic shielding members have been developed in order to prevent electromagnetic waves radiated from electronic devices from reaching the surroundings or to protect electronic devices or human bodies from electromagnetic waves.

  Electromagnetic waves can be shielded by a conductive material. Whether or not the electromagnetic wave shielding material or the electromagnetic wave shielding member has optical transparency is irrelevant to the shielding of the electromagnetic wave, but in a display device such as a plasma display panel, the electromagnetic wave radiated from the display surface reaches the surroundings. Since it is desired to shield the electromagnetic wave so as to prevent it, the electromagnetic wave shielding member for such an application is required to have high light transmittance in addition to the electromagnetic wave shielding performance.

  As an electromagnetic wave shielding member having high light transmittance, for example, an electromagnetic wave shielding member described in Patent Document 1 is known. In this electromagnetic wave shielding member, a metal thin film (hereinafter referred to as “mesh metal layer”) formed in a mesh shape is laminated on a transparent film substrate via an adhesive or a pressure-sensitive adhesive.

  The mesh metal layer is formed, for example, by laminating a metal foil on a transparent film substrate via an adhesive or a pressure-sensitive adhesive, and then patterning the metal foil into a mesh. Since the metal foil is relatively thick, it is easy to ensure sufficient conductivity even if it is formed into a mesh, and as a result, it is easy to obtain an electromagnetic wave shielding member having high electromagnetic wave shielding performance. In addition, since the metal foil is formed in a mesh shape, a region corresponding to the mesh eye functions as a light transmitting portion, and high light transmittance is easily obtained.

However, since the surface of the metal foil is relatively rough, the region of the adhesive or pressure-sensitive adhesive used for joining the metal foil, where the metal foil is subsequently removed by patterning and becomes a light transmitting portion, The surface shape remains as a rough surface area transferred to the surface, which contributes to a decrease in light transmittance. Moreover, the irregular reflection of light on the side surface of the mesh-like metal layer becomes a factor of reducing the light transmittance of the electromagnetic wave shielding member. For this reason, the planarization layer which consists of transparent resin is formed so that a mesh-shaped metal layer and each light transmission part may be coat | covered as needed. In addition, when the flatness of the surface of the flattening layer is low, moire and interference unevenness occur when this electromagnetic wave shielding member is placed on the display device, so that a flattening layer with high surface flatness is formed. In addition, a substrate having excellent flatness is laminated on the transparent resin before curing, and the substrate having excellent flatness is peeled off after the transparent resin is cured (after the flattening layer is formed). The
Japanese Patent Application Laid-Open No. 2002-311843 (refer to the claims, the 0030th stage and the 0060th stage)

  However, in the electromagnetic wave shielding member described in Patent Document 1, since the metal foil used as a material is relatively thick as described above, the mesh-shaped metal layer and each light transmission portion are covered so as to cover the planarizing layer. When a transparent resin is applied, large irregularities are likely to occur on the surface of the resulting planarized layer. If there are large irregularities on the surface of the electromagnetic wave shielding member, it is difficult to obtain an electromagnetic wave shielding member having high light transmittance and high image sharpness (hereinafter simply referred to as “image sharpness”) viewed through the electromagnetic wave shielding member. become.

  In addition, a substrate having excellent flatness is laminated on the transparent resin before curing, and the substrate having excellent flatness is peeled off after the transparent resin is cured (after the flattening layer is formed). Although the technique is useful for obtaining a planarized layer having a high surface flatness, the above-mentioned base material does not eventually become a constituent member of the electromagnetic wave shielding member. There exists a problem that the manufacturing cost of a member rises.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electromagnetic wave shielding member that can be easily obtained while suppressing manufacturing costs while having high light transmission and high image clarity. is there.

  The electromagnetic wave shielding member of the present invention that achieves the above object is formed of a transparent base material, a mesh-like metal layer that is formed on the transparent base material and defines a number of light transmission portions in plan view, and a transparent resin. The mesh-shaped metal layer and a cured coating film that covers the multiple light-transmitting portions, and the region of the cured coating film that is located on the mesh-shaped metal layer is a plan view of the light-transmitting portion. A raised portion is formed so as to rise from the region located in the upper central portion, and the average inclination angle of the raised portion on the fine line portion of the mesh-like metal layer is 10 ° or less (characterized in that Hereinafter, this electromagnetic wave shielding member may be referred to as “electromagnetic wave shielding member I”).

  In the electromagnetic wave shielding member I of the present invention, since the average inclination angle of the raised portion on the fine wire portion of the mesh-like metal layer is suppressed to 10 ° or less, irregular reflection of light on the surface of the cured coating film, and electromagnetic waves Generation of light glare (so-called rainbow unevenness) at the shielding member is suppressed. In addition, as described later, the cured coating film can be formed by coating the material once to form a coating film, and then curing the coating film. . Therefore, according to the electromagnetic wave shielding member I of the present invention, it becomes easy to obtain a material having high light transmittance and high image definition while suppressing the manufacturing cost.

  In the present invention, the “fine line portion of the mesh-like metal layer” means a region of the mesh-like metal layer that extends in one direction without branching in the other direction.

  In the electromagnetic wave shielding member I of the present invention, (1) the mesh metal layer is joined to the transparent base material with a bonding agent (hereinafter, this electromagnetic wave shielding member is referred to as “electromagnetic wave shielding member II”). Is preferred).

  According to the electromagnetic wave shielding member II of the present invention, a relatively thick metal foil can be used as the material for the mesh-like metal layer, so that it is easy to obtain an electromagnetic wave shielding member having high electromagnetic wave shielding performance. In addition, the area where the metal foil is removed by patterning on the surface of the bonding agent remains as a rough surface area where the surface shape of the metal foil is transferred to the surface, but this rough surface area is covered with the cured coating film described above. Therefore, irregular reflection of light on the surface of the rough surface area is suppressed, and as a result, it becomes easy to obtain high light transmittance and high image definition.

  In both of the electromagnetic wave shielding member I and the electromagnetic wave shielding member II of the present invention, (2) the transparent resin has a chain structure (hereinafter, this electromagnetic wave shielding member may be referred to as “electromagnetic wave shielding member III”). Or (3) the transparent resin has a crosslinked structure (hereinafter, this electromagnetic wave shielding member may be referred to as “electromagnetic wave shielding member IV”).

  In the electromagnetic wave shielding members I to IV of the present invention, (4) the glass transition point of the transparent resin is within a range of 30 to 150 ° C. (hereinafter, this electromagnetic wave shielding member may be referred to as “electromagnetic wave shielding member V”). .) Or (5) The average value of the maximum film thickness of the cured coating film on the fine line portion of the mesh-like metal layer is in the range of 1 to 20 μm (hereinafter, this electromagnetic wave shielding member is referred to as “ It is sometimes referred to as “electromagnetic wave shielding member VI”).

  According to the electromagnetic wave shielding member V of the present invention, the shape retention ability of the cured coating film is sufficiently high in practical use, so that it is easy to provide an electromagnetic wave shielding member with good durability.

  According to the electromagnetic wave shielding member VI of the present invention, since the maximum film thickness of the cured coating film on the fine line portion of the mesh-like metal layer is within the above range, the cured coating film is suppressed while suppressing the absorption of light by the cured coating film. It becomes easy to suppress irregular reflection of light on the surface of the film and so-called rainbow unevenness on the electromagnetic wave shielding member, and as a result, it becomes easier to obtain high image clarity while maintaining high light transmittance. .

  In the electromagnetic wave shielding members I to VI of the present invention, (6) the cured coating film contains an infrared absorber (hereinafter, this electromagnetic wave shielding member may be referred to as “electromagnetic wave shielding member VII”), Is preferred.

  According to the electromagnetic wave shielding member VII of the present invention, infrared rays can be absorbed. Therefore, an electromagnetic wave shielding member for a plasma display panel, particularly an electromagnetic wave shielding member disposed on a display surface, which is desired to absorb infrared rays together with shielding of electromagnetic waves. Can be obtained.

  According to the electromagnetic wave shielding member of the present invention, it becomes easy to obtain an electromagnetic wave shielding member having high light transmittance and high image definition while suppressing the manufacturing cost. Therefore, the electromagnetic wave shielding member is radiated from the display surface of a display device such as a plasma display panel. Therefore, it is easy to provide an electromagnetic wave shielding member that can shield the electromagnetic wave to be shielded while suppressing deterioration of the image quality of the visually recognized image at a low cost.

  FIG. 1 (a) is a partially cutaway plan view schematically showing an example of the electromagnetic wave shielding member of the present invention, and FIG. 1 (b) is an outline of a cross section taken along the line I-I shown in FIG. 1 (a). FIG. The electromagnetic wave shielding member 20 shown in these drawings includes a transparent base material 1, a mesh-like metal layer 10 joined to the transparent base material 1 with a bonding agent 5, and a cured coating film 15 formed of a transparent resin. Have. Hereinafter, it explains in full detail for each of these members, and the modification of an electromagnetic wave shielding member is demonstrated after that.

(1) transparent substrate;
The transparent substrate 1 is for supporting the mesh-like metal layer 10. As this transparent base material 1, it is possible to use a transparent rigid material with poor flexibility such as a glass substrate or a transparent resin substrate, but it increases the degree of freedom in selecting the installation location of the electromagnetic wave shielding member 20. From the viewpoint or from the viewpoint of increasing the productivity of the electromagnetic wave shielding member 20, it is preferable to use a highly flexible material such as a glass sheet, a transparent resin sheet, or a transparent resin film.

  The material of the transparent substrate 1 can be appropriately selected according to the use of the electromagnetic wave shielding member 20 and the allowable production cost. Further, the light transmittance of the transparent substrate 1 can be appropriately selected according to the use of the electromagnetic wave shielding member 20. For example, when the electromagnetic wave shielding member 20 is disposed on the display surface of the display device, the transparent substrate 1 may be polyethylene terephthalate, polyethylene naphthalate, polycarbonate, acrylic resin, cyclic polyolefin, triacetyl cellulose, poly It is preferable to use a film or sheet formed of ether sulfide, polyether ketone or the like and having a film thickness of about 12 to 300 μm and a visible light transmittance (total light transmittance) of about 80% or more.

(2) bonding agent;
The bonding agent 5 is used for bonding the metal foil to the transparent substrate 1 by a dry lamination method, a wet lamination method, or the like when the mesh-like metal layer 10 is formed by patterning of the metal foil, or as desired. After the metal foil is patterned into a mesh shape, the metal foil is bonded onto the transparent substrate 1 by a dry lamination method, a wet lamination method, or the like. Since this bonding agent 5 forms a layer on the transparent substrate 1 as shown in the figure, it is hereinafter referred to as “bonding layer 5”. It is preferable that the bonding agent layer 5 has practically sufficient bonding strength, etching resistance, and light resistance.

  Specific examples of the bonding agent layer 5 include thermosetting or photocurable adhesives such as acrylic, ester, urethane, fluorine, polyimide, epoxy, or polyurethane ester, or the main component. Examples include a layer formed of an acrylic pressure-sensitive adhesive containing methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, or the like. In addition, “(meth) acrylate” in the present specification means both acrylate and methacrylate.

  The film thickness of the bonding agent layer 5 can be appropriately selected within a range of about 0.5 to 50 μm depending on the type of bonding agent used. When the metal foil bonded on the transparent substrate 1 by the bonding agent layer 5 is patterned by wet etching to form the mesh-like metal layer 10, the type is selected so that the bonding agent layer 5 also functions as an etching stopper. It is preferable to select the film thickness. In order to obtain the electromagnetic wave shielding member 20 having high light transmittance and high image definition, it is preferable to reduce the difference in refractive index between the bonding agent layer 5 and the transparent substrate 1, and light having a wavelength of 587.6 nm is measured light. And the refractive index difference is about 0.2 or less, more preferably 0.1 or less.

  The mesh metal layer 10 is formed by forming a metal layer as a base material on the transparent substrate 1 by, for example, vapor deposition, and patterning the metal layer, or through a mask having a predetermined shape. The metal can be formed by vapor-depositing the metal on the transparent substrate 1. In these cases, the bonding agent layer 5 can be omitted.

(3) mesh metal layer;
The mesh-shaped metal layer 10 is a member for shielding electromagnetic waves while keeping the light transmittance of the electromagnetic wave shielding member 20 high, and defines a large number of light transmission portions 12 on the transparent substrate 1 in plan view. The planar shape of each light transmission part 12 can be selected as appropriate, for example, a triangle, a quadrangle, a hexagon, or the like. The planar shape of each light transmission part 12 in the electromagnetic wave shielding member 20 of this embodiment is a quadrangle. In the mesh-like metal layer 10, each region that defines the side of the light transmission part 12 in plan view is a thin line part 10 a. Hereinafter, a region serving as a base point for each of the four thin line portions 10a is referred to as an “intersection 10b”.

  The mesh-like metal layer 10 can be formed of a metal such as copper, iron, nickel, chromium, aluminum, gold, silver, stainless steel, tungsten, chromium, or titanium. From the viewpoint of obtaining the electromagnetic wave shielding member 20 having both high light transmittance and high electromagnetic wave shielding performance at low cost, the mesh-like metal layer is made of a metal that is inexpensive, has a low surface reflectance, and is highly conductive, such as copper. 10 is preferably formed. In order to manufacture the electromagnetic wave shielding member 20 having high electromagnetic wave shielding performance at low cost, a desired metal foil is bonded onto the transparent substrate 1 by the bonding agent layer 5 described above, and this metal foil is desired by wet etching. It is preferable to form the mesh-like metal layer 10 by patterning into a shape or to join the transparent metal substrate 1 with the bonding agent layer 5 after patterning a desired metal foil into the mesh shape. A rolled foil or an electrolytic foil can be used as the metal foil, but a rolled foil is preferable from the viewpoint of low cost.

  The aperture ratio of the mesh-like metal layer 10 (percentage of the total area of the light-transmitting portion 12 in plan view that occupies the sum of the area of the mesh-like metal layer 10 in plan view and the total area of the light-transmitting portion 12 in plan view) ) Is about 70% or more, it becomes easy to obtain the electromagnetic wave shielding member 20 having a high light transmittance. At this time, the average line width in a plan view of the thin wire portion 10a is preferably about 20 μm or less, particularly preferably 15 μm or less.

  On the other hand, from the viewpoint of enhancing the electromagnetic wave shielding performance of the electromagnetic wave shielding member 20, it is preferable to increase the conductivity of the mesh metal layer 10, so depending on the material of the mesh metal layer 10, the average film thickness may be reduced. It is desirable that the thickness is about 5 to 30 μm, preferably about 5 to 15 μm, and that the average line width in plan view at the thin wire portion 10a is 5 μm or more.

  When the electromagnetic wave shielding member 20 is disposed on the display surface of the display device, it is desirable to increase the image clarity of the electromagnetic wave shielding member 20 in addition to enhancing the light transmission of the electromagnetic wave shielding member 20. It is. From the viewpoint of increasing the image definition of the electromagnetic wave shielding member 20, the ten-point average roughness (Rz) of the surface of the mesh metal layer 10 is preferably about 0.1 μm or more, particularly about 0.5 μm or more. When the surface of the mesh-like metal layer 10 is a mirror surface, the external image reflected on the surface of the mesh-like metal layer 10 is easily visually recognized. As a result, the image definition of the electromagnetic wave shielding member 20 is lowered. When the value of the ten-point average roughness (Rz) exceeds 3 μm, when the mesh-like metal layer 10 is bonded onto the transparent substrate 1, bubbles easily remain at the interface between the two, and appropriate bonding becomes difficult.

  Further, among the upper and lower surfaces of the mesh-like metal layer 10 or the upper and lower surfaces of the base material of the mesh-like metal layer 10, at least the surface that comes outside when the electromagnetic wave shielding member 20 is arranged on the display surface, The image definition of the electromagnetic wave shielding member 20 can also be increased by performing blackening treatment by a method such as chromate treatment.

  For example, when a copper foil having a ten-point average roughness (Rz) of about 0.1 to 3 μm is used as the base material of the mesh-like metal layer 10 and the planar shape of each light transmission part 12 is a rectangle, The average thickness of the mesh-like metal layer 10 is about 5 to 15 μm, the average line width in plan view at the thin line portion 10 a is about 5 to 15 μm, and the size of each light transmission portion 12 in plan view is 150. By setting it to about ˜400 μm □, it becomes easy to obtain the electromagnetic wave shielding member 20 having high electromagnetic wave shielding performance, light transmittance, and high image definition.

(4) Cured coating film;
The cured coating film 15 is the most characteristic component in the present invention, and is formed of a transparent resin and covers the mesh-like metal layer 10 and each light transmission portion 12. A region of the cured coating film 15 located on the mesh-like metal layer 10 is located at the center of the light transmission part 12 in plan view as shown in FIGS. 1 (a) and 1 (b). A raised portion 15a is formed so as to rise from the region.

  Since the mesh-like metal layer 10 is a relatively thick film, the raised portion 15a is formed when the thickness of the cured coating film 15 is made as thin as possible to cover the mesh-like metal layer 10 and each light transmission portion 12. Inevitable. If the thickness of the cured coating film 15 is increased, it is possible to suppress the formation of the raised portion 15a. However, as the thickness of the cured coating film 15 is increased, the amount of light absorbed by the cured coating film 15 increases. As a result, the light transmittance and image definition of the electromagnetic wave shielding member 20 are lowered. Moreover, it becomes difficult to form the cured coating film 15 by one coating.

  When the raised portion 15a is formed on the cured coating film 15, the maximum film thickness of the raised portion 15a on the intersecting portion 10b of the mesh-like metal layer 10 is usually on the fine line portion 10a of the mesh-like metal layer 10. It becomes thicker than the maximum film thickness of the raised portion 15a. The raised portion 15a functions as a minute convex lens on each intersection 10b. For this reason, the degree of divergence and convergence of the light transmitted through the electromagnetic wave shielding member 20 is determined in the vicinity of the thin wire portion 10a of the mesh-like metal layer 10, the vicinity of the intersecting portion 10b of the mesh-like metal layer 10, and the plane of the light transmission portion 12. It differs from the visual center. If this difference is large, so-called rainbow unevenness or the like occurs in the electromagnetic wave shielding member 20 and the image definition is lowered.

  However, in the electromagnetic wave shielding member 20, since the average inclination angle of the raised portion 15a on the thin wire portion 10a is suppressed to 10 ° or less, the above difference is small. For this reason, the electromagnetic wave shielding member 20 provides high image definition. Here, the “average inclination angle of the cured coating film on the thin line portion” as used in the present invention means an average inclination angle determined as follows.

  First, as shown in FIG. 2, the electromagnetic shielding member 20 has a cross section in a direction orthogonal to the longitudinal direction of the thin wire portion 10 a, and the upper surface of the cured coating film 15 at the center portion in plan view of the light transmission portion 12. As a reference, the height L1 of the top portion P of the cured coating film 15 (the raised portion 15a) on the thin wire portion 10a is measured. Further, a vertical line VL passing through the apex P (which means a normal to the surface of the transparent substrate 1) is virtually drawn, and the distance from the apex P on the vertical line VL corresponds to 90% of L1. Find B. In FIG. 2, the distance between the apex P and the point B is represented by L2. Next, a horizontal line HL that passes horizontally through the point B is virtually drawn on the surface of the transparent substrate 1, and intersections C1 and C2 between the horizontal line HL and the slope of the cured coating film 15 (the raised portion 15a) are obtained. And a distance L3 between the point B1 and the point C1, and a distance L4 between the point B and the point C2. Thereafter, tan θ1 = L2 / L3 is set, and an average value Av of θ1 and θ2 calculated as tan θ2 = L2 / L4 is obtained. Similarly, average value Av is calculated | required about the cured coating film 15 (protrusion part 15a) on the some thin wire | line part 10a extracted arbitrarily. The arithmetic average of these average values Av is the “average inclination angle of the cured coating film on the thin line portion” in the present invention. In FIG. 2, hatching is omitted for convenience.

  Such a cured coating film 15 can be formed of a transparent resin having a chain structure, or can be formed of a transparent resin having a crosslinked structure. Specifically, (i) a solvent-diluted transparent resin composition that is solidified only by volatilizing the solvent, (ii) a thermosetting transparent resin composition that cures by polymerization reaction or crosslinking reaction by heating, Or (iii) a transparent resin composition that is cured by a polymerization reaction or a crosslinking reaction by irradiation with electromagnetic waves (hereinafter, this transparent resin composition is referred to as a “photo-curable transparent resin composition”). Can be used. In this specification, the coating film obtained by solidifying this solvent dilution type transparent resin composition by volatilizing the solvent of a solvent dilution type transparent resin composition shall also be contained in a "cured coating film."

  Specific examples of the solvent-diluted transparent resin composition include acrylic resins, polyester resins, polycarbonate resins, polyurethane resins, cyclic polyolefin resins, polystyrene resins, fluorine resins, polyimide resins and the like as solvents. The one diluted with is mentioned.

  Specific examples of the thermosetting transparent resin composition include an acrylic resin, a polyester resin, a polycarbonate resin, a polyurethane resin, a cyclic polyolefin resin, a polystyrene resin, a fluorine resin by polymerization or crosslinking, The thing etc. which become a polyimide-type resin are mentioned.

  And as said photocurable transparent resin composition, what contains the monomer component and the oligomer component at least is preferable. Specific examples of the monomer component include (A) vinyl monomers such as vinyl acetate, styrene, N-vinylpyrrolidone, (B) butyl acrylate, 2-ethylhexyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, n-decyl acrylate, Monofunctional acrylate monomers such as isobornyl acrylate, dicyclopentenyloxyethyl acrylate, phenoxyethyl acrylate, (C) 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, diethylene glycol diacrylate, neopentyl Glycol diacrylate, polyethylene glycol 400 diacrylate, tripropylene glycol diacrylate, bisphenol A diethoxydiacrylate, tetraethylene glycol Over diacrylate, hydroxy Bibari acid neopentyl glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, polyfunctional acrylate monomers such as dipentaerythritol hexaacrylate, and the like. Specific examples of the oligomer component include epoxy acrylate, urethane acrylate, polyester acrylate, polyether acrylate, silicon acrylate, polybutadiene acrylate, unsaturated polyester, polyene / thiol, and polystyryl methacrylate.

  Examples of the fluorine-based resin mentioned in the description of the specific examples of the solvent-diluted transparent resin composition and the thermosetting resin composition include polytetrafluoroethylene, polychlorotrifluoroethylene, and tetrafluoroethylene. Copolymer of hexafluoropropylene, terpolymer of tetrafluoroethylene, perfluoroalkyl vinyl ether and hexafluoropropylene, copolymer of tetrafluoroethylene and ethylene or propylene, ethylene and chlorotrifluoroethylene Examples include copolymers, perfluoroalkoxy resins, vinylidene fluoride resins, vinyl fluoride resins, and the like. Similarly, examples of the polyimide resin include polyimide, polyamideimide, and polyetherimide.

  In addition, the thermosetting transparent resin composition and the photocurable transparent resin composition can each contain at least one of a polymerization initiator and a sensitizer, if necessary. For example, specific examples of the polymerization initiator (photopolymerization initiator) contained in the photocurable transparent resin composition include acetophenone, benzophenone, 4,4-bisdimethylaminobenzophenone, benzyl, benzoin, benzoin ethyl ether, and benzoin butyl ether. Benzoin isobutyl ether, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-dimethoxy-1-phenylpropan-1-one, 1- (4-isopropylphenyl) -2 -Hydroxy-2-methylpropan-1-one, azobisisobutylnitrile, 2-chlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, 3,3-dimethyl-4- Methoxybenzopheno 2,4-dimethylthioxanthone, methylbenzoyl formate, 3,3,4,4-tetra (t-butylperoxycarbonyl) benzophenone, etc. Specific examples of the sensitizer include n-butylamine. , Triethylamine, N-methyldiethanolamine, triethyl-n-butylphosphine, diethylaminoethyl methacrylate, ethyl p-dimethylaminobenzoate, isobutyl p-dimethylaminobenzoate, 2-dimethylaminoethylbenzoate and the like.

  Electromagnetic wave shielding member having high light transmission and high image clarity regardless of whether a solvent-diluted transparent resin composition, a thermosetting transparent resin composition, or a photocurable transparent resin composition is used as the material of the cured coating film 15 In order to suppress reflection at the interface between the cured coating film 15 and the bonding agent layer 5, the difference in refractive index when using light with a wavelength of 587.6 nm as measurement light is about 0.2 or less. Furthermore, it is preferable to select the material so that it becomes 0.1 or less. If the refractive index difference between the cured coating film 15 and the bonding agent layer 5 is about the above value or less, the unevenness on the surface of the metal foil used as the material of the mesh-like metal layer 10 is the bonding agent layer in the light transmitting portion 12. Even if it is transferred to the surface 5, reflection of light at the interface between the surface and the cured coating film 15 is suppressed, so that it is easy to obtain the electromagnetic wave shielding member 20 having high light transmittance and high image clarity. For the same reason, when the electromagnetic wave shielding member 20 does not have the bonding agent layer 5, the refractive index difference between the cured coating film 15 and the transparent substrate 1 is preferably set to about the above value or less.

  In order to suppress light reflection on the surface of the cured coating 15 and generation of so-called rainbow unevenness on the electromagnetic wave shielding member 20 while suppressing absorption of light by the cured coating 15, the fine line portion of the mesh-like metal layer 10 While the average value of the maximum film thickness of the cured coating film 15 on 10a (hereinafter, this average value is abbreviated as “average value I”) within the range of about 1 to 20 μm, the above-mentioned average inclination angle (hereinafter referred to as “average inclination angle”) The average inclination angle “abbreviated as“ average inclination angle I ””) is preferably 10 ° or less.

  If the average value I is greater than about 20 μm, the amount of light absorbed by the cured coating film 15 increases, and the light transmittance of the electromagnetic wave shielding member 20 may decrease. Further, when a transparent resin composition containing a solvent is used as the material of the cured coating film 15, the amount of residual solvent in the cured coating film 15 is increased, and the cured coating film 15 is liable to be floated or cracked, As a result, the light transmittance and image definition of the electromagnetic wave shielding member 20 are likely to be lowered. Even when any of a solvent-diluted transparent resin composition, a thermosetting transparent resin composition, and a photocurable transparent resin composition is used as the material of the cured coating film 15, the average value I is about 1 to 15 μm. More preferably, it is within the range.

In the case where a cured coating film 15 having an average value I and an average inclination angle I within the above ranges is to be efficiently formed by one coating using a solvent-diluted transparent resin composition, The viscosity of is within the range of about 0.01 to 10 Pa · s, and the coating amount (which means the coating amount after curing (solidification)) is appropriately within the range of about 10 to 35 g / m ² . It is preferable to select. The viscosity is more preferably in the range of about 0.03 to 1 Pa · s, and the coating amount is more preferably selected as appropriate in the range of about 15 to 25 g / m ² .

  The solvent-diluted transparent resin composition satisfying the above viscosity condition is obtained by, for example, diluting a transparent resin having a number average molecular weight of about 1,000 to 300,000 with a solvent so that the solid content is in a range of about 15 to 35 wt%. Can be obtained. At this time, the number average molecular weight of the transparent resin is preferably in the range of about 5,000 to 150,000, and the solid content is preferably in the range of about 15 to 30 wt%.

Moreover, when it is going to form efficiently the cured coating film 15 in which the average value I and the average inclination | tilt angle I are each in said range using a thermosetting type transparent resin composition by one coating, it is 23. The viscosity at ° C. is preferably in the range of about 0.01 to 2 Pa · s, and the coating amount (however, the coating amount after curing) is in the range of about 10 to 50 g / m ² . It is preferable to select appropriately. The viscosity is more preferably in the range of about 0.05 to 0.2 Pa · s, and the coating amount is more preferably selected in the range of about 10 to 25 g / m ² .

And when it is going to form efficiently the cured coating film 15 in which the average value I and the average inclination angle I are each in said range using a photocurable transparent resin composition by one coating, it is the 23 The viscosity at ° C. is preferably in the range of about 0.03 to 5 Pa · s, and the coating amount (however, the coating amount after curing) is in the range of about 10 to 35 g / m ² . It is preferable to select appropriately. The viscosity is more preferably in the range of about 0.05 to 1 Pa · s, and the coating amount is more preferably selected in the range of about 15 to 25 g / m ² .

  The thermosetting transparent resin composition and the photocurable transparent resin composition that satisfy the above-described viscosity conditions can be obtained by appropriately adjusting, for example, the monomer content or the solvent content, respectively.

  Even when any of a solvent-diluted transparent resin composition, a thermosetting transparent resin composition, and a photocurable transparent resin composition is used as the material of the cured coating film 15, the viscosity of the transparent resin composition is within the above range. When the cured coating film 15 is formed, the base on the transparent base material 1 side in the mesh-like metal layer 10 and the bonding agent layer 5 (the transparent base material 1 when the bonding agent layer 5 is omitted) and It can also be easily suppressed that bubbles remain in the corners formed by the.

  From the viewpoint of obtaining the electromagnetic wave shielding member 20 having high light transmittance and high image definition, it is also preferable to set the ten-point average roughness (Rz) of the surface of the cured coating film 15 to about 0.05 to 7 μm. If this ten-point average roughness (Rz) is out of the above range, the amount of reflected light on the surface of the cured coating film 15 increases, or the irregular reflection on the surface of the cured coating film 15 increases, resulting in an electromagnetic wave shielding member. The image clarity of 20 may be lowered. The ten-point average roughness (Rz) of the surface of the cured coating film 15 is more preferably in the range of about 0.1 to 5 μm. If this ten-point average roughness (Rz) is within the above-mentioned range, even when another member is stuck on the cured coating film 15, bubbles hardly remain at the interface between the two.

  When the solvent-diluted transparent resin composition is used as the material of the cured coating film 15, the cured coating film 15 having a ten-point average roughness (Rz) within the above range is, for example, a coating film having a temperature of 50 to 130 ° C. It can obtain by drying over 1 to 3 minutes with a hot air with a wind speed of 2 to 20 m / sec. At this time, it becomes easy to obtain a good cured coating film 15 by reducing the residual solvent amount as much as possible. In order to reduce the amount of residual solvent in the cured coating film 15, it is preferable to increase the temperature and speed of the hot air stepwise to prevent the coating surface from drying out too early. For example, in the initial stage, it is dried with hot air at a temperature of 50 to 70 ° C. and a wind speed of 2 to 5 m / sec, and further dried with hot air at a temperature of 100 to 130 ° C. and a wind speed of 10 to 20 m / sec at the stage where the coating film surface is dried, A good cured coating film 15 with little or no residual solvent can be obtained.

Further, even when a thermosetting transparent resin composition or a photocurable transparent resin composition is used as the material of the cured coating film 15, when these transparent resin compositions contain a solvent, the above drying conditions are used. It is preferable to evaporate the solvent under the same conditions as described above, and then advance the polymerization reaction or crosslinking reaction by heating or irradiation with electromagnetic waves. In curing the thermosetting transparent resin composition, it is preferably cured for 1 to 7 days in an environment at a temperature of 40 ° C to 60 ° C. Moreover, when hardening a photocurable transparent resin composition, it is preferable to make the irradiation intensity | strength of the electromagnetic waves which can harden the said photocurable transparent resin composition into the range of about 50-1000 mJ / cm < ² >. When the photocurable transparent resin composition is an ultraviolet curable transparent resin composition, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a metal halide lamp, a pulse xenon lamp, or the like can be used as an ultraviolet light source. .

  In order to make the shape retention ability of the cured coating film 15 sufficiently practical, it is preferable that the glass transition point is 30 ° C. or higher and the number average molecular weight is several thousand or higher. When the solvent-diluted transparent resin composition is used as the material of the cured coating film 15, the glass transition point and the number average molecular weight of the transparent resin contained in the transparent resin composition are substantially unchanged, and the cured coating film 15 Glass transition point and number average molecular weight. On the other hand, when a thermosetting transparent resin composition or a photocurable transparent resin composition is used as the material of the cured coating film 15, the cured coating film 15 can be selected by appropriately selecting the curing conditions of the transparent resin composition. The glass transition point and the number average molecular weight of can be controlled. The upper limit of the number average molecular weight of the cured coating film 15 is not particularly limited, but when a solvent-diluted transparent resin composition is used as a material, the transparent resin composition is about 300,000 or less, particularly about 150,000 or less. Is preferably selected. Moreover, when using a thermosetting transparent resin composition or a photocurable transparent resin composition as a material, it is preferable to set it as about 5 million or less, especially about 3 million or less. If the glass transition point of the cured coating film 15 is within the above range, for example, when the electromagnetic wave shielding member 20 is produced by roll-to-roll, it is easy to suppress occurrence of blocking during winding.

  In the electromagnetic wave shielding member 20 having the above-described structure, since the above-described cured coating film 15 is formed, irregular reflection of light on the upper surface and side surfaces of the mesh metal layer 10 when the transparent substrate 1 is used as a reference. Further, irregular reflection of light on the surface of the cured coating film 15 and generation of so-called rainbow unevenness in the electromagnetic wave shielding member 20 are suppressed, and as a result, it becomes easy to obtain high light transmittance and high image definition. . Moreover, since the cured coating film 15 can be formed by coating the material once to form a coating film and curing the coating film, the manufacturing cost can be easily suppressed. Therefore, in the electromagnetic wave shielding member 20 of the present invention, it is easy to obtain a material having high light transmittance and high image definition while suppressing the manufacturing cost. Furthermore, since the surface of the cured coating film 15 is relatively flat, bubbles may remain between the cured coating film 15 and other members even when another member is stuck on the cured coating film 15. As a result, steps such as defoaming can be omitted.

  The electromagnetic wave shielding member 20 is suitable for shielding electromagnetic waves radiated from the display surface of a display device such as a plasma display panel while suppressing deterioration in the image quality of a visually recognized image.

(5) Modifications;
The electromagnetic wave shielding member of the present invention is not limited to the above-described form, and various modifications, improvements, combinations, and the like are possible. Hereinafter, some modified examples will be described by appropriately quoting the reference numerals used in FIG. 1A or FIG.

  For example, infrared rays are also emitted from the display surface of the plasma display panel, and this infrared rays may cause malfunction of peripheral devices such as a remote controller. Therefore, it is preferable that the electromagnetic wave shielding member of the present invention has an infrared absorbing ability to absorb near infrared rays in a wavelength range of 800 to 1200 nm as necessary. This infrared absorbing ability is obtained, for example, by containing an infrared absorber in at least one of the bonding agent layer 5 and the cured coating film 15, or on the outer surface of the transparent substrate 1 or on the outer surface of the cured coating film 15. It can be imparted by forming an infrared absorbing layer. It can also be applied by applying an infrared absorbing film on the outer surface of the transparent substrate 1 or on the outer surface of the cured coating film 15.

  When the bonding agent layer 5 or the cured coating film 15 contains an infrared absorber, the infrared absorber includes tin oxide, indium oxide, magnesium oxide, titanium oxide, chromium oxide, zirconium oxide, nickel oxide, aluminum oxide, and oxidation. Inorganic infrared absorbers such as zinc, iron oxide, antimony oxide, lead oxide, bismuth oxide, cyanine compounds, phthalocyanine compounds, naphthalocyanine compounds, naphthoquinone compounds, anthraquinone compounds, aluminum compounds, pyrylium compounds, Organic infrared absorbers such as cerium-based compounds, squarylium-based compounds, diimoniums, copper complexes, nickel complexes, and dithiol-based complexes can be used. An infrared absorber may contain only 1 type and may contain 2 or more types.

  The content of the infrared absorber in the bonding agent layer 5 or the cured coating film 15 is 20% in the near-infrared transmittance in the wavelength range of 800 to 1200 nm (however, the transmittance of the whole electromagnetic wave shielding member is meant). It is preferable to select appropriately according to the type of infrared absorber to be used so that it is about 10% or less, particularly about 10% or less. The “near-infrared transmittance” as used herein means the near-infrared transmittance measured using UV-310OPC (trade name) manufactured by Shimadzu Corporation.

  When the bonding agent layer 5 or the cured coating film 15 contains an infrared absorber, an infrared absorption film or an infrared absorption layer was provided on the outer surface of the transparent substrate 1 or the outer surface of the cured coating film 15. Since there is no increase in the number of optical interfaces as compared with the case, the decrease in the light transmittance and the image sharpness of the electromagnetic wave shielding member due to the provision of the infrared absorbing ability is suppressed.

  In addition, when making the bonding agent layer 5 or the cured coating film 15 contain an infrared absorbent, infrared rays are used in the bonding agent layer 5 and the cured coating film 15 from the viewpoint of suppressing deterioration and decomposition of the infrared absorbent. It is preferable that the hydroxyl value in the layer or film to contain the absorbent is 10 or less, further 5 or less, particularly 0. From the same viewpoint, it is preferable that the acid value in the layer or film in which the infrared absorber is to be contained in the bonding agent layer 5 and the cured coating film 15 is 10 or less, further 5 or less, particularly 0. As used herein, “hydroxyl value” means the number of milligrams of potassium hydroxide required to neutralize acetic acid bound to an acetylated product obtained from 1 mg of a sample. Further, the “acid value” in the present specification means the number of milligrams of potassium hydroxide necessary to neutralize free fatty acids in 1 g of a sample. The hydroxyl value and acid value in each of the bonding agent layer 5 and the cured coating film 15 can be controlled by appropriately selecting materials of these layers or films.

  Further, the plasma display panel emits light from a rare gas used as a discharge gas. For example, when neon (Ne) gas is used as the rare gas, orange light emission occurs. Such light emission from the rare gas becomes a factor of deteriorating the image quality of the display image. Therefore, it is preferable that the electromagnetic wave shielding member of the present invention is provided with a light absorbing ability to absorb light emitted from a rare gas used as a discharge gas, if necessary. This light absorbing ability is obtained by, for example, containing an appropriate light absorbing dye in at least one of the bonding agent layer 5 and the cured coating film 15, or on the outer surface of the transparent substrate 1 or the outer surface of the cured coating film 15. It can be provided by forming a suitable light absorption layer on the top.

  For example, cyanine dyes, polymethine dyes, subphthalocyanine dyes, porphyrin dyes, and the like can be used as light absorbing dyes for absorbing light emitted from neon gas. The light-absorbing dye can be mixed with the above-described infrared absorber, or the layer or film containing the light-absorbing dye and the layer or film containing the infrared absorber can be made separate from each other. Is possible.

  The above light absorbing layer is composed of, for example, the above-described light absorbing dye and an acrylate-based pressure-sensitive adhesive such as one having 2-ethylhexyl acrylate as a main component or a pressure-sensitive adhesive having butyl acrylate as a main component, toluene, methyl ethyl ketone, acetic acid. A coating solution is prepared by dissolving in a solvent such as ethyl, butyl acetate, methyl isobutyl ketone, isopropyl alcohol, and the coating solution is applied on the outer surface of the transparent substrate 1 or the outer surface of the cured coating film 15. After the coating film is formed, the coating film can be formed by drying.

  In addition, in the electromagnetic wave shielding member of the present invention, an antireflection film, a shock absorbing layer, or the like can be laminated on the transparent substrate 1 or the cured coating film 15.

<Example 1>
First, a 100 μm thick polyethylene terephthalate film (A4300 (trade name) manufactured by Toyobo Co., Ltd.) was prepared as a transparent substrate, and a 9 μm thick copper foil (Furukawa Circuit) using a urethane-based adhesive on one side of the film. Foyle EXP-WS (trade name)) was dry-laminated. The copper foil was blackened on one side by chromate treatment, and was arranged so that the blackened surface (chromate treated surface) was the outer surface during dry lamination.

  The refractive index of light having a wavelength of 587.6 nm in the polyethylene terephthalate film is 1.57. The urethane adhesive used for dry lamination has a glass transition point of 20 ° C., a number average molecular weight of 30,000, an acid value of 1, a hydroxyl value of 9, and a refractive index of light with a wavelength of 587.6 nm of 1.49. The film thickness is 10 μm.

  Next, a resist pattern having a predetermined shape was formed on the copper foil, and the copper foil was wet etched using this resist pattern as an etching mask. At this time, a ferric chloride solution was used as an etchant, and the liquid temperature was 50 ° C. After wet etching, the resist pattern was peeled off and rinsed with pure water. As a result, a mesh-like metal layer having a lattice shape with a size and shape in plan view of each eye of 300 μm □ and a line width in plan view of the thin line portion of 10 μm was obtained. This mesh-like metal layer defines a large number of light transmitting portions having a size and shape of 300 μm □ in plan view in the above-described polyethylene terephthalate film.

  Separately from this, a commercially available solvent-diluted transparent resin composition (BR-98 (trade name) manufactured by Mitsubishi Rayon Co., Ltd.) was prepared. This solvent-diluted transparent resin composition comprises a methyl methacrylate transparent resin having a glass transition point of 65 ° C., a number average molecular weight of 60,000, an acid value of 1 and a hydroxyl value of 0: 1: 1 of toluene and methyl ethyl ketone. (Weight ratio) It is diluted with a mixed solution, and the methyl methacrylate transparent resin has a chain structure.

Next, the above solvent-diluted transparent resin composition is used as a base composition, and this base composition is diluted 5 times (weight ratio) with a 1: 1 (weight ratio) mixture of toluene and methyl ethyl ketone. A working solution was prepared, and this coating solution was applied onto the mesh-like metal layer and each of a large number of light transmitting portions using an applicator. The coating amount was such that the coating amount after drying (dry weight) was 20 g / m ² .

  Thereafter, the obtained coating film was dried with hot air having a wind speed of 5 m / sec and a temperature of 60 ° C. for 30 seconds, and subsequently dried with hot air having a wind speed of 20 m / sec and a temperature of 100 ° C. for 60 seconds. Thereby, the cured coating film which each coat | covers a mesh-shaped metal layer and many light transmission parts was formed with transparent resin, and the electromagnetic wave shielding member was obtained. Hereinafter, a plurality of electromagnetic wave shielding members were produced under the same conditions.

  About the coating liquid (transparent resin composition) used for preparation of the electromagnetic wave shielding member in the present Example 1 and Examples 2 to 12 and Comparative Examples 1 to 4 described later, the trade name, type, dilution factor of the base composition, The presence / absence of the polymerization initiator, the presence / absence of the infrared absorber (IR absorber), and the coating conditions of the coating liquid are listed in Table 1 below.

  Further, the glass transition point, the number average molecular weight, the acid value, and the hydroxyl value of the formed cured coating film, and the surface of the cured coating film in the electromagnetic shielding member randomly extracted from the plurality of electromagnetic shielding members. Point average roughness (Rz), average film thickness at the light transmission part (average value of film thickness at the central part of the light transmission part in plan view), and average value of distance L2 (see FIG. 2) at the raised part The average value of the distance L3 and the distance L4 shown in FIG. 2 and the average inclination angle of the cured coating film on the fine line portion of the mesh-like metal layer are listed and shown in Table 2 below.

The surface roughness (ten-point average roughness (Rz)) of the cured coating film is a surface roughness meter (HANDYSURF E-35A (trade name) manufactured by Tokyo Seimitsu Co., Ltd.) in any of the examples and comparative examples. ^Was measured according to JIS B0601-2001.

<Examples 2 to 6>
For each example, the solvent-diluted transparent resin composition shown in Table 1 below is used as the coating solution, and the coating amount of the coating solution (however, the weight after curing) is shown in Table 1. A plurality of electromagnetic wave shielding members were produced for each example under the same conditions as in Example 1 except for the amounts shown in FIG. In addition, all the transparent resin in each solvent dilution type transparent resin composition has a chain structure.

<Example 7>
Under the same conditions as in Example 1 except that the thermosetting transparent resin composition shown in Table 1 below was used as the coating liquid, and this coating film was heated at 60 ° C. for 4 days after drying. In addition, a plurality of electromagnetic wave shielding members were produced. By further heating the coating film after drying, a cured coating film made of a crosslinked transparent resin was formed on each electromagnetic wave shielding member. The coating film was dried under the same conditions as the drying of the coating film in Example 1.

<Examples 8 to 9>
As the coating liquid, a photocurable (ultraviolet curable) transparent resin composition shown in Table 1 below is used, and the coating amount (however, the weight after curing) is 17 g / m ² or 20 g / m. A coating film is formed at m ² , and a plurality of coatings are formed under the same conditions as those in Example 1 except that after drying the coating film, ultraviolet rays are irradiated using an ultraviolet lamp under conditions of an irradiation intensity of 400 mJ / cm ^2. The electromagnetic shielding member was prepared for each example. By irradiating the coating film with ultraviolet rays, a cured coating film made of a crosslinked transparent resin was formed on each electromagnetic wave shielding member. The coating film was dried under the same conditions as the drying of the coating film in Example 1.

<Examples 10 to 12>
As shown in Table 1 below, the coating liquid (transparent resin composition) contains an infrared absorber, and the coating amount of the coating liquid (however, it means the weight after curing). A plurality of electromagnetic wave shielding members were produced for each example under the same conditions as in Example 2, Example 3, or Example 7 except for the amounts shown in Table 1.

<Comparative Example 1>
A plurality of electromagnetic wave shielding members were produced under the same conditions as in Example 1 except that a cured coating film was not formed.

<Comparative Examples 2-3>
As shown in Table 1 or Table 2, under the same conditions as in Example 4 except that the dilution rate or the coating amount of the coating solution was changed when preparing the coating solution (solvent-diluted transparent resin composition). In addition, a plurality of electromagnetic wave shielding members were produced for each comparative example.

<Comparative example 4>
As shown in Table 1 or 2, under the same conditions as in Example 8, except that the dilution rate or the coating amount of the coating solution was changed when preparing the coating solution (photocurable transparent resin composition). In addition, a plurality of electromagnetic wave shielding members were produced.

[Evaluation]
About the electromagnetic wave shielding member produced in each of Examples 1 to 12 and Comparative Examples 1 to 4, haze, luminous transmittance, and image definition were measured by the following methods. Moreover, about each electromagnetic wave shielding member of Examples 10-12 which made the cured coating film contain the infrared absorber, the infrared transmittance was measured by the following method. These results are shown in Table 3.

(A) haze;
Using a color computer SM-C (trade name) manufactured by Suga Test Instruments Co., Ltd., according to JIS K ^7105-1981 “Testing methods for optical properties of plastics”, values immediately after production (initial), temperature 60 ° C., humidity 95% The value was measured after the durability test was performed in the air atmosphere for 1000 hours (after the test).

(B) Luminous transmittance;
Using the image clarity measuring device ICM-1 (product surface) manufactured by Suga Test Instruments Co., Ltd., according to JIS ^K7105-1981 “Plastic Optical Properties Test Method”, the value immediately after production (initial), temperature 60 ° C., humidity 90 % After being left in an air atmosphere for 1000 hours to conduct a durability test (after the test), and measured by the transmission method.

(C) Image definition;
Using the above-described image clarity measuring device, in accordance with JIS K ^7105-1981 “Testing method for optical properties of plastics”, 1000 hours in an air atmosphere immediately after production (initial) and in an air atmosphere at a temperature of 60 ° C. and a humidity of 95% The transmission sharpness after the durability test was performed after standing (after the test) was measured. As the optical combs, a total of five types were used in which the width of each of the dark part and the bright part was 0.125 mm, 0.25 mm, 0.5 mm, 1 mm, or 2 mm.

(D) infrared transmittance;
About the maximum transmittance of near-infrared rays in the wavelength range of 800 to 1200 nm, the value immediately after the production (initial) and the durability test after being left in an air atmosphere at a temperature of 60 ° C. and a humidity of 90% for 1000 hours (test The value in “after” was measured using a spectrophotometer (UV-3100PC (product number)) manufactured by Shimadzu Corporation.

  Comparison of haze, luminous transmittance and image sharpness in each electromagnetic wave shielding member produced in Examples 1 to 12 with haze, luminous transmittance and image sharpness in the electromagnetic wave shielding member produced in Comparative Example 1. As is clear from the above, an electromagnetic wave shielding member having a small haze, a high luminous transmittance and a high image definition is obtained by forming a cured coating film covering each of the mesh-like metal layer and a large number of light transmitting portions with a transparent resin. Can be obtained.

  In addition, as apparent from the comparison between the initial values of the haze, luminous transmittance, and image clarity of the electromagnetic wave shielding members prepared in Examples 1 to 6 and Examples 10 to 12, and the values after the test. Even when a cured coating film is formed by simply solidifying the solvent-diluted transparent resin composition, the cured coating film is formed by the thermosetting transparent resin composition or the photo-curing type (ultraviolet curing type) transparent resin composition. Similarly to the electromagnetic wave shielding members of Examples 8 and 9, it is possible to obtain an electromagnetic wave shielding member having high durability in terms of light transmittance and image sharpness.

  As is clear from the comparison between the electromagnetic wave shielding member produced in Example 2, Example 4 or Example 7 and the electromagnetic wave shielding member produced in Examples 10 to 12, an infrared absorber was contained in the cured coating film. Even in this case, it is possible to easily obtain an electromagnetic wave shielding member having the same values as the case where the haze, the luminous transmittance, and the image definition are not included in the infrared absorber.

  And the comparison between the electromagnetic wave shielding member produced in Example 4 and the electromagnetic wave shielding member produced in Comparative Examples 2 to 3, and the electromagnetic wave shielding member produced in Example 8 and the electromagnetic wave shielding member produced in Comparative Example 4 As is clear from the above, the luminous transmittance and the image definition of the electromagnetic wave shielding member are relatively strongly affected by the average inclination angle of the cured coating film (the protruding portion) on the fine line portion of the mesh-like metal layer. By reducing the average inclination angle, the luminous transmittance and the image definition can be improved. In other words, by controlling the average inclination angle, an electromagnetic wave shielding member having high light transmission and high image definition can be obtained.

  Note that no bubbles were observed in any of the electromagnetic wave shielding members produced in Examples 1 to 12.

FIG. 1 (a) is a partially cutaway plan view schematically showing an example of the electromagnetic wave shielding member of the present invention, and FIG. 1 (b) is an outline of a cross section taken along the line I-I shown in FIG. 1 (a). FIG. It is a schematic diagram for demonstrating how to obtain | require the "average inclination angle of the cured coating film on a thin wire | line part" as used in the field of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent base material 5 Adhesive bond layer 10 Mesh-like metal layer 10a Fine wire part 12 Light transmission part 15 Cured coating film 15a Raised part 20 Electromagnetic wave shielding member

Claims (7)

A transparent base material, a mesh-like metal layer that is formed on the transparent base material and defines a plurality of light-transmitting portions in plan view, and a mesh-shaped metal layer and the plurality of light-transmitting portions that are formed of a transparent resin. Having a cured coating to coat,
Of the cured coating film, a region located on the mesh-like metal layer is raised above a region located at a central portion in plan view of the light transmission portion to form a raised portion, and the mesh-like metal The electromagnetic wave shielding member, wherein an average inclination angle of the raised portion in the thin line portion of the layer is 10 ° or less. The electromagnetic shielding member according to claim 1, wherein the mesh metal layer is bonded onto the transparent base material with a bonding agent.   The electromagnetic shielding member according to claim 1, wherein the transparent resin has a chain structure.   The electromagnetic wave shielding member according to claim 1, wherein the transparent resin has a crosslinked structure.   The electromagnetic wave shielding member according to any one of claims 1 to 4, wherein the glass transition point of the transparent resin is within a range of 30 to 150 ° C.   6. The average value of the maximum film thickness of the cured coating film on the fine line portion of the mesh-shaped metal layer is in the range of 1 to 20 μm, according to claim 1. Electromagnetic wave shielding member. The electromagnetic wave shielding member according to claim 1, wherein an infrared absorber is contained in the cured coating film.

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