JP2010080835A - Electromagnetic wave shielding material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic wave shielding material which can prevent whisker-like matter because of a conductive paste from being generated. <P>SOLUTION: A portion of a primer layer where a convex mesh pattern layer is formed has a thickness larger than that of a portion where such a convex mesh pattern layer is not formed. Interfacial surfaces between the primer layer in the convex mesh pattern layer portion and the convex mesh pattern layer have any one, or two or more of: (a) a sectional form where the interfacial surfaces of the primer layer and the convex mesh pattern layer are intricately formed in a nonlinear manner; (b) a sectional form including layers mixed with a component constituting the primer layer and a component constituting the convex mesh pattern layer; and (c) a sectional form where a component contained in the primer layer exists in a conductive composition constituting the convex mesh pattern layer. The convex mesh pattern layer includes an electromagnetic wave shielding material formed by intersection of a first direction line portion and a second direction line portion which are composed of parallel line groups in different first and second directions, with a level difference ΔH between the first direction line portion and the second direction line portion being less than 0.5 μm. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electromagnetic wave shielding material that shields electromagnetic waves with a conductive layer formed in a predetermined pattern.

  As a display device such as a monitor of a television or a personal computer, for example, a cathode ray tube (CRT) display device, a liquid crystal display device (LCD), a plasma display device (PDP), an electroluminescence (EL) display device and the like are known. Among these display devices, plasma display devices that are attracting attention in the field of large-screen display devices use plasma discharge for light emission. Therefore, unnecessary electromagnetic waves in the 30 MHz to 1 GHz band leak to the outside and other devices ( For example, remote control devices, information processing apparatuses, etc.) may be affected. Therefore, it is common to provide a film-like electromagnetic shielding material for shielding electromagnetic waves that leak from the front side (observer side) of the plasma display panel used in the plasma display device.

  Various electromagnetic shielding materials have been studied so far. For example, in Patent Document 1, an electroless plating catalyst paste is screen-printed in a mesh pattern on a transparent substrate, and a metal layer is electrolessly plated thereon. An electromagnetic shielding material has been proposed. Patent Document 2 discloses that a conductive ink composition is intaglio offset printed on a transfer body in a mesh pattern, the mesh pattern on the transfer body is transferred onto a transparent substrate, and a metal layer is formed on the mesh pattern on the transparent substrate. An electromagnetic shielding material obtained by electroplating is proposed. Patent Document 3 proposes an electromagnetic wave shielding material obtained by intaglio printing a conductive ink composition directly on a transparent substrate with a mesh pattern, and electroplating a metal layer on the mesh pattern on the transparent substrate. Yes.

JP 11-170420 A JP 2001-102792 A Japanese Patent Laid-Open No. 11-174174

  However, the electromagnetic wave shielding material described in Patent Document 1 forms a mesh pattern by screen printing, which is difficult to form a fine pattern, and forms a metal layer by electroless plating with a slow film formation speed. There is a disadvantage that it is inferior and the cost cannot be reduced. Further, the electromagnetic shielding material described in Patent Document 2 forms a mesh pattern by intaglio printing, so that a fine pattern can be formed. However, since offset printing is adopted, the transfer from the intaglio to the transfer body is performed. Since the second transfer is performed on the transparent substrate, the intaglio mesh pattern as the original plate may not be faithfully transferred to the transparent substrate.

  Furthermore, the electromagnetic wave shielding materials described in Patent Documents 2 and 3 generate untransferred portions or transfer defects that are poor in adhesion when transferring (also referred to as transfer) from the intaglio to the transfer body or transparent substrate. Sometimes. Specifically, as shown in FIG. 8, when the conductive ink composition 103 is applied on the intaglio plate 101 and then scraped with a doctor blade 102 to fill the recess 104 with the conductive ink composition 103, FIG. As shown to (B), the conductive ink composition 103 in the recessed part 104 after scraping with the doctor blade 102 has the dent 105 in the upper part. The recess 105 is then formed as shown in FIG. 8C when the transparent base 106 is pressure-bonded onto the intaglio 101 and the conductive ink composition 103 in the recess 104 is transferred onto the transparent base 106. This is a factor that hinders adhesion between the transparent substrate 106 and the conductive ink composition 103. As a result, an untransferred portion of the conductive ink composition occurs on the transparent substrate 106, or a transfer failure that is inferior in adhesiveness occurs, which causes electromagnetic wave shielding characteristics to deteriorate.

Therefore, the present applicant transfers a conductive material composition onto a transparent substrate by intaglio printing, and forms an electrically conductive pattern in an electromagnetic shielding material, and the pattern based on transfer failure of the conductive material composition. PCT / JP2008 / 60427 (filing date: June 6, 2008, hereinafter referred to as “prior invention”) is proposed as an electromagnetic shielding material that does not cause defects such as disconnection, shape defects, and low adhesion. ing. In the invention of the prior application, as shown in FIG. 8 (C), the dent 105 of the conductive ink composition 103 shown in FIG. 8 (B) is formed with a primer layer that can maintain fluidity until it is cured. The pressure-sensitive adhesive process is performed by pressing the primer layer and the conductive ink in the concave portion 104 without gaps, the primer layer is cured, and the transparent base material is peeled off from the plate surface. The composition is transferred onto the cured primer layer. In such a method, in the transfer step, when the conductive ink composition is peeled from the intaglio, peeling electrification occurs, and as a result, a part of the uncured conductive ink composition is patterned by electrostatic force. There was a problem of protruding from the line portion toward the opening portion 111 in a beard shape or scattering in a dot shape at the opening portion (hereinafter, these are collectively referred to as “beard-like object”). As shown in FIG. 11, when the whiskers W are present in the opening 111, the appearance deteriorates and the light transmittance is lowered, and it cannot be used as an electromagnetic shielding material.
When producing an electromagnetic wave shielding material, the present invention peels off the transparent base material from the plate surface, pulls out the uncured conductive material composition (hereinafter also referred to as “conductive paste”) in the plate recess, and forms a transparent substrate. An object of the present invention is to provide an electromagnetic wave shielding material capable of preventing the generation of whiskers in the step of transferring onto the primer layer of the material.

As a result of intensive studies to solve the above problems, in order to prevent the occurrence of paste whiskers when the conductive paste is drawn, the step between the first direction line portion and the second direction line portion of the convex mesh pattern layer is adjusted. It was found that this could be solved. The present invention has been completed based on such findings.
That is, the present invention
(1) An electromagnetic shielding material having a transparent substrate, a primer layer formed on the transparent substrate, and a convex mesh pattern layer made of a conductive composition formed in a predetermined pattern on the primer layer There,
Of the primer layer, the portion where the convex mesh pattern layer is formed is thicker than the portion where the convex mesh pattern layer is not formed, and the convex mesh pattern layer is formed. The interface between the primer layer and the convex mesh pattern layer in the part is (a) a cross-sectional configuration in which the interface between the primer layer and the convex mesh pattern layer is in a non-linear manner, and (b) constitutes the primer layer And a cross-sectional form having a layer in which the component constituting the convex mesh pattern layer is mixed, and (c) contained in the primer layer in the conductive composition constituting the convex mesh pattern layer The convex mesh pattern layer has a flat surface running in a first direction and a second direction different from each other. A first direction line portion and a second direction line portion formed of a line group are configured to cross each other, and a step ΔH between the first direction line portion and the second direction line portion is less than 0.5 μm. Electromagnetic shielding material,
(2) The electromagnetic wave shielding material according to (1), wherein a metal layer is further formed on the surface of the convex mesh pattern layer,
Is to provide.

In the mesh pattern obtained by the present invention, the step between the first direction line portion and the second direction line portion is within a predetermined range. (A) When forming by intaglio printing, the mesh pattern relatively protrudes around the line portion. Has no scattered parts, so-called whiskers, and even when the metal layer is coated on the mesh pattern by electrolytic plating, the electric lines of force are difficult to concentrate on the protrusions, and the whiskers grow by plating. Since the volume of starting point is small, there is virtually no generation of whiskers, and (ii) when applying an adhesive layer or a resin layer on the mesh, it is difficult for bubbles to remain due to whiskers.
Further, the thickness of the portion of the primer layer where the convex mesh pattern layer is formed is larger than the thickness of the portion where the convex mesh pattern layer is not formed, and the primer in the convex mesh pattern layer forming portion The interface between the layer and the convex mesh pattern layer is (a) a cross-sectional form in which the interface between the primer layer and the convex mesh pattern layer is in a non-linear manner, and (b) the component constituting the primer layer and the convex mesh. A cross-sectional form having a layer mixed with a component constituting the pattern layer, and (c) a cross-section in which the component contained in the primer layer is present in the conductive composition constituting the convex mesh pattern layer (C) Good adhesion between the primer layer and the conductive composition layer, (d) When forming a pattern by intaglio printing, the conductive composition has good transferability and no transfer defects. The pattern reproducibility is good, and even if peeling occurs when the conductive composition is transferred from the intaglio, the surroundings of the conductive composition are prevented from being scattered and the appearance of the opening is poor and the light transmittance is reduced. To prevent. As a result, there is an effect that good electromagnetic wave shielding properties can be obtained.

  Next, embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present invention.

[Electromagnetic wave shielding material]
FIG. 1 is a schematic plan view showing an example of the electromagnetic wave shielding material of the present invention, and FIG. 2 is an enlarged view of the AA ′ cross section in FIG. FIG. 3 is a schematic cross-sectional view showing a part of FIG. 2 further enlarged. The electromagnetic wave shielding material 10 of the present invention has a transparent substrate 1, a primer layer 2 formed on the transparent substrate 1, and a convex mesh pattern layer 3 formed in a predetermined pattern on the primer layer 2. And it has the metal layer 4 formed on the convex mesh pattern layer 3 as needed, and also has the protective layer 9 as needed. In FIG. 1, reference numeral 7 is an electromagnetic wave shielding pattern portion, and reference numeral 8 is a grounding portion. Further, the “predetermined pattern” is a mesh-like pattern that is common as an electromagnetic wave shielding pattern of the electromagnetic wave shielding material 10. Hereinafter, the configuration of the present invention will be described in detail.

[Transparent substrate]
The transparent substrate 1 may be appropriately selected from known materials and thicknesses in consideration of required physical properties such as transparency in the visible region (light transmittance), heat resistance, and mechanical strength, such as glass and ceramics. A plate-like rigid body such as a transparent inorganic plate or a resin plate may be used. However, a flexible resin film (or sheet) is preferable in consideration of suitability for continuous processing with a roll-to-roll having excellent productivity. The roll-to-roll refers to a processing method in which the material is unwound and supplied from a winding (roll), appropriately processed, and then wound and stored in the winding.

Examples of resins for resin films and resin plates include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), ethylene glycol-1,4 cyclohexanedimethanol-terephthalic acid copolymer, ethylene glycol-terephthalic acid-isophthalic acid copolymer. Polyester resins such as polymers, acrylic resins such as polymethyl methacrylate, polyolefin resins such as polypropylene and cycloolefin polymers, cellulose resins such as triacetyl cellulose, polycarbonate resins, polyimide (PI) resins, etc. is there. Among them, polyethylene terephthalate is a transparent base material whose biaxially stretched film is preferable in terms of heat resistance, mechanical strength, light transmittance, cost, and the like.
Examples of the transparent inorganic material include soda glass, potash glass, borosilicate glass, lead glass, and other transparent ceramics such as PLZT and quartz.

  The thickness of the transparent substrate is basically not particularly limited and is appropriately selected depending on the application. When a flexible resin film is used, it is, for example, about 12 to 500 μm, preferably about 25 to 200 μm. In the case of using a resin or transparent inorganic plate, the thickness is, for example, about 500 to 5000 μm.

[Primer layer]
The primer layer 2 improves the ink (conductive composition) transferability from the plate to the printing material (transparent substrate) during the printing of the convex mesh pattern layer 3, and the conductive composition after the transfer. This is a layer for improving the adhesion between the product and the printing material. That is, both the transparent base material and the convex mesh pattern layer have good adhesion, and it is also a transparent layer for ensuring the light transmittance of the opening (the convex mesh pattern layer non-formed part).
Further, the primer layer 2 is a layer that is provided on the transparent substrate 1 in a state where fluidity can be maintained, and is formed as a layer that solidifies from a liquid while in contact with the intaglio at the time of intaglio printing. This layer is solidified when a typical electromagnetic shielding material is formed.

The material constituting the primer layer is not particularly limited. However, in the present invention, an ionizing radiation curable composition containing a liquid (fluid) ionizing radiation polymerizable compound in an uncured state is applied and cured ( A layer formed by solidification) is preferably used. Hereinafter, this material will be mainly described in detail.
As the ionizing radiation polymerizable compound, monomers and / or prepolymers that are polymerized and cured by a reaction such as crosslinking with ionizing radiation are used.
Examples of such monomers include radically polymerizable monomers such as methyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, isobornyl (meth) acrylate, and dicyclopentenyl (meth) ) Monofunctional (meth) acrylates such as acrylate, dipropylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate , Pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) a Polyfunctional (meth) acrylates of various (meth) acrylates such relations and the like. Here, the expression (meth) acrylate means acrylate or methacrylate. Examples of the cationic polymerizable monomer include alicyclic epoxides such as 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexene carboxylate, glycidyl ethers such as bisphenol A diglycidyl ether, 4-hydroxybutyl vinyl ether And vinyl ethers, and oxetanes such as 3-ethyl-3-hydroxymethyloxetane.
In addition, as the prepolymer (or oligomer), as the radical polymerizable prepolymer, various (meth) such as urethane (meth) acrylate, epoxy (meth) acrylate, polyester (meth) acrylate, triazine (meth) acrylate, and the like. Examples thereof include polythiol-based prepolymers such as acrylate prepolymers, trimethylolpropane trithioglycolate, pentaerythritol tetrathioglycolate, and unsaturated polyester prepolymers. Other examples of the cationic polymerizable prepolymer include novolac type epoxy resin prepolymer and aromatic vinyl ether type resin prepolymer.
These monomers or prepolymers may be used alone or in combination of two or more types of monomers, two or more types of prepolymers, or one type of monomer, depending on the required performance, coating suitability, etc. A mixture of the above and one or more prepolymers can be used.

When ultraviolet rays or visible rays are employed as the ionizing radiation, a photopolymerization initiator is usually added. As a photopolymerization initiator, in the case of a radical polymerizable monomer or prepolymer, a compound such as a benzophenone-based, thioxanthone-based, benzoin-based, or acetophenone-based compound, or in the case of a cationic polymerization-based monomer or prepolymer, Metallocene, aromatic sulfonium and aromatic iodonium compounds are used. These photopolymerization initiators are added in an amount of about 0.1 to 5 parts by mass with respect to 100 parts by mass of the composition comprising the monomer and / or prepolymer.
In addition, as the ionizing radiation, ultraviolet rays or electron beams are typical, but in addition, electromagnetic waves such as visible rays, X-rays and γ rays, or charged particle beams such as α rays and various ion rays are used. You can also.

  The ionizing radiation curable composition may contain a solvent, but in that case, a drying step is required after coating, and therefore it is preferable that the ionizing radiation curable composition is a type that does not contain a solvent (non-solvent type).

  Although the thickness (TB) of the primer layer 2 is not particularly limited, it is usually formed to have a thickness after curing of about 1 μm to 100 μm. Further, the thickness (TB) of the primer layer 2 is usually the sum of the convex mesh pattern layer 3 and the primer layer 2 (total thickness. The top of the convex mesh pattern layer 3 in FIG. 3A). And the difference in altitude between the surface of the transparent substrate 1 and the surface of the transparent substrate 1).

[Convex mesh pattern layer made of conductive composition]
In the electromagnetic wave shielding material of the present invention, the convex mesh pattern layer 3 made of a conductive composition is provided on the primer layer 2 in a predetermined pattern. The line width and the inter-line pitch may be dimensions that are usually employed. For example, the line width can be 5 to 50 μm, and the line-to-line pitch can be 100 to 500 μm. The aperture ratio (ratio of the total area of the openings in the total area of the electromagnetic shielding pattern) is usually about 50 to 95%. In addition to the electromagnetic shielding pattern of the mesh, there may be a case where a grounding pattern such as all the solids is provided on the entire periphery or a part of the periphery of the mesh while maintaining electrical connection therewith.
Moreover, although the thickness of the convex mesh pattern layer 3 varies depending on the resistance value of the convex mesh pattern layer 3, the balance between the electromagnetic wave shielding performance and the suitability for adhesion of other members onto the convex mesh pattern layer is considered. In the measurement at the central portion (the top of the projection pattern), it is usually 2 μm or more and 50 μm or less, preferably 5 μm or more and 20 μm or less.
The convex mesh pattern layer 3 is obtained by forming a conductive composition (conductive ink or conductive paste) containing conductive particles and a binder resin on the primer layer 2 by an intaglio printing method described later. Can do.

  The conductive particles constituting the conductive composition include particles of low resistivity metal such as gold, silver, platinum, copper, nickel, tin, and aluminum, or high resistivity metal particles and resin particles as core particles. The particles such as inorganic particles whose surface is coated with a low resistivity metal such as gold or silver can be preferably mentioned, and the shape is also spherical, spheroidal, regular polyhedral, truncated polyhedral, scaly, It can be selected from a disk shape, a dendritic shape, a fiber shape, and the like. These materials and shapes may be appropriately mixed and used. Since the size of the conductive particles is arbitrarily selected according to the type, it cannot be specified unconditionally. For example, in the case of flaky silver particles, those having an average particle diameter of about 0.1 to 10 μm are used. be able to. Although content of the electroconductive particle in an electroconductive composition is arbitrarily selected according to the electroconductivity of an electroconductive particle or the form of particle | grains, for example, among 100 mass parts of solid content of an electroconductive composition, it is electroconductive. The particles can be contained in the range of 40 to 99 parts by mass. In the present specification, the average particle diameter refers to a value measured by a particle size distribution meter or TEM (transmission electron microscope) observation.

As the binder resin constituting the conductive composition, any of thermosetting resins, ionizing radiation curable resins, and thermoplastic resins can be used. Examples of the thermosetting resin include resins such as melamine resin, polyester-melamine resin, epoxy-melamine resin, phenol resin, polyimide resin, thermosetting acrylic resin, thermosetting polyurethane resin, and thermosetting polyester resin. Examples of the ionizing radiation curable resin include the above-described materials as the primer material. Examples of the thermoplastic resin include a thermoplastic polyester resin, a polyvinyl butyral resin, a thermoplastic acrylic resin, a thermoplastic polyurethane resin, and the like. Can be mentioned. In addition, when using a thermosetting resin, you may add a curing catalyst as needed. When using an ionizing radiation curable resin, a photopolymerization initiator may be added as necessary.
Further, in order to obtain fluidity suitable for filling the concave portion of the plate, these resins are usually used as a varnish dissolved in a solvent. There is no restriction | limiting in particular in the kind of solvent, The solvent generally used for printing ink can be used. The content of the solvent is usually about 10 to 70% by mass, but it is preferably as small as possible within a range where necessary fluidity is obtained. In addition, when an ionizing radiation curable resin is used, a solvent is not necessarily required because it is inherently fluid.

  Also, in order to improve the fluidity and stability of the conductive composition, as long as the conductivity and adhesion to the primer layer are not adversely affected, a filler, a thickener, an antistatic agent, and a surfactant are appropriately used. Antioxidants, dispersants, anti-settling agents and the like may be added.

[Method of manufacturing electromagnetic shielding material]
Hereinafter, the manufacturing method of the electromagnetic wave shielding material of the present invention will be described in detail with reference to the drawings.
FIG. 4 is a process diagram showing an example of the method for producing an electromagnetic wave shield of the present invention. FIG. 5 is a schematic configuration diagram of an apparatus for performing the manufacturing method of the present invention, and FIG. 6 is a schematic configuration diagram of an apparatus for performing a transfer process for transferring a conductive material composition onto a primer layer. .

  The method for producing an electromagnetic wave shield of the present invention is a method for producing an electromagnetic wave shielding material 10 (see FIG. 2) in which a convex mesh pattern layer 3 is formed on one surface of a transparent substrate 1, which is shown in FIGS. As shown in FIG. 6, the transparent base material preparation process which prepares the transparent base material 1 in which the primer layer 2 which can hold | maintain fluidity until it hardens | cures was formed in one surface S1, and the recessed part 64 by the convex-shaped mesh pattern A conductive material for forming a cured product having conductivity after curing on a plate-like or cylindrical plate surface 63 formed with a step depth Δh between the one-direction line portion and the second-direction line portion being less than 0.5 μm. After the composition 15 is applied, a filling step (see FIG. 4B) of scraping off the conductive material composition adhering to other than the inside of the concave portion and filling the concave portion 64 with the conductive material composition 15; The concave surface 64 side of the plate surface 63 after the process and the transparent after the transparent substrate preparation process A pressure bonding step (see FIG. 4C) in which the conductive material composition 15 in the concave portion 64 and the primer layer 2 are closely bonded without pressure by pressure bonding to the primer layer 2 side of the bright substrate 1, and a primer after the pressure bonding step. A primer curing step for curing the layer 2 and a transfer step for peeling the transparent substrate 1 from the plate surface 63 after the primer curing step and transferring the conductive material composition 15 in the recesses onto the primer layer 2 (see FIG. 4D). ) And a curing step (see FIG. 4E) for curing the conductive composition layer 3 ′ formed in a predetermined pattern on the primer layer 2 after the transfer step. Hereinafter, each step will be described with reference to the drawings.

(Transparent substrate preparation process)
The transparent base material preparation step is a step of preparing the transparent base material 1 in which the primer layer 2 that can maintain fluidity until it is cured is formed on one surface S1. The primer layer 2 is formed by applying a primer layer resin composition on the transparent substrate 1, and since the primer layer resin composition is as described above, the description thereof is omitted here. The transparent substrate 1 having the primer layer 2 may be a purchased product or may be formed by a coating method as shown in FIG. Sometimes it is necessary for the primer layer 2 to be in a fluid state.

For example, when a curable resin composition is used as the primer layer resin composition, only the solvent in the ionizing radiation curable resin composition is dried and removed in an unirradiated state without irradiation with ionizing radiation. It is preferable to form the primer layer 2 in a fluid state on the material as a coating film and supply the primer layer 2 to the pressure-bonding step described later in that state. Of course, when the photocurable resin composition used here is a so-called non-solvent (solvent-free) type that does not contain a solvent, a drying step when forming the primer layer 2 is unnecessary.
Further, when a thermoplastic resin composition is used as the primer layer resin composition, the primer layer 2 may be heated immediately before the pressure bonding step as long as it is in a fluidized state by heating in the pressure bonding step described later. Alternatively, the primer layer 2 may be heated and pressure-bonded to the printing plate simultaneously with a hot roll or the like.

In addition, about the method of apply | coating a primer layer, various coating systems can be used, For example, it can select suitably from various systems, such as a roll coat, a gravure roll coat, a comma coat, and a die coat.
The coating method shown in FIG. 5 is an example of a gravure reverse coat, and a film-like transparent substrate 1 wound in a roll shape is introduced between a gravure roll 51 and a backup roll 52 to provide photocurability for a primer layer. This is a method of applying a resin composition. In this case, the gravure roll 51 comes into contact with the ionizing radiation curable resin composition filled container 53 at the lower side, and the ionizing radiation curable resin composition is pulled up and applied to one surface of the transparent substrate 1. At this time, excess ionizing radiation curable resin composition is scraped off by the doctor blade 54. After the ionizing radiation curable resin composition is applied on the transparent substrate 1, a drying treatment of the solvent contained in the resin composition is performed as necessary. This drying process is, for example, a process in which only the solvent in the ionizing radiation curable resin composition adjusted to a viscosity suitable for the coating apparatus is dried and removed to form a primer layer 2 in a fluid state for use in the subsequent pressure bonding process. is there. When a non-solvent type ionizing radiation curable resin composition having a viscosity suitable for a coating apparatus is used, a drying apparatus is unnecessary. The transparent substrate 1 having the primer layer 2 that retains fluidity is then supplied to the crimping process.

(Resin filling process)
As shown in FIGS. 4 (a) and 4 (b), the resin filling step forms a convex mesh pattern after curing on a plate or cylindrical plate surface 63 in which concave portions 64 are formed in a predetermined mesh or stripe pattern. In this step, the conductive material composition 15 capable of forming the layer 3 is applied, and then the conductive material composition adhering to other than the inside of the recess is scraped to fill the recess with the conductive material composition 15. Since the conductive material composition 15 is as described above, the description thereof is omitted here.

The combination of the conductive material composition with respect to the primer layer resin composition is not particularly limited, and the curing process of the primer layer resin composition and the curing process of the conductive material composition may be different. When an ionizing radiation curable resin containing conductive powder is employed as the conductive material composition 15, the primer layer resin composition is also preferably an ionizing radiation curable resin composition. By such a combination, curing of the primer layer 2 and curing of the conductive material composition layer 3 can be simultaneously performed by the ionizing radiation irradiation treatment in the crimping step after the resin filling step and the subsequent curing step of the primer layer. Can do. At this time, when the ionizing radiation to be irradiated is light or ultraviolet light, it can be cured by selecting an appropriate combination of a photopolymerization initiator and a photocurable resin. In the case of ultraviolet irradiation, it is necessary to consider that only the surface of the conductive powder that does not transmit light such as black is easily cured, and the inner resin is difficult to cure.
Moreover, when irradiating an electron beam, it is not necessary to consider the color of the conductive powder.

  Note that the coating method shown in FIGS. 5 and 6 is an example of a process performed before the transparent base material 1 having the primer layer 2 is pressure-bonded to the intaglio roll 62. Specifically, the pickup roll 61 is conductive. The material composition filling container 68 is brought into contact with the lower side, and the conductive material composition 15 is pulled up and applied to the plate surface 63 of the intaglio roll 62. At this time, the conductive material composition 15 is scraped off by the doctor blade 65 so that the conductive material composition 15 does not get on the portion other than the concave portion 64 on the plate surface 63.

(Crimping process)
As shown in FIGS. 4C and 6, the crimping process is performed by crimping the concave portion 64 side of the plate surface 63 after the resin filling process and the primer layer 2 side of the transparent substrate 1 after the transparent substrate preparation process. In this step, the conductive material composition 15 in the recess 64 and the primer layer 2 are closely adhered without a gap. The pressure bonding is performed by the nip roll 66 and urged against the intaglio roll 62 with a predetermined pressure. The nip roll 66 is provided with a biasing pressure adjusting means, and the biasing pressure is arbitrarily adjusted according to the fluidity of the primer layer 2.
When the primer layer 2 is a thermoplastic resin, the nip roll 66 is preferably a heatable roll. In this case, the primer layer 2 is softened and flowable by thermocompression bonding.

(Curing process)
The curing step is a step of curing the primer layer 2 after the pressure bonding step by the urging force of the nip roll 66, and the primer layer 2 and the conductive material composition 15 are in close contact with each other by performing a curing process after the pressure bonding. Can be cured. Specifically, when the primer layer resin composition is an ionizing radiation curable resin composition, ionizing radiation is irradiated in the irradiation zone shown in FIG. In this case, the primer layer is sandwiched between the transparent substrate and the plate surface, and is not subject to inhibition of curing by oxygen in the air, so a nitrogen purge device or the like is not necessarily required.
The curing treatment is selected in accordance with the types of the primer layer resin composition and the conductive material composition as described above, and is subjected to curing treatment such as ionizing radiation irradiation treatment and cooling treatment.

(Transfer process)
As shown in FIG. 4D, the transfer step is a step of peeling the transparent substrate 1 from the plate surface 63 of the intaglio roll 62 and transferring the conductive material composition 15 in the recess 64 onto the primer layer 2 after the curing step. It is. Since the primer layer 2 has been cured in the primer curing step prior to this step, the conductive material composition 15 that is in close contact with the primer layer 2 is removed from the plate surface 63 of the intaglio roll 62 so that the conductive material composition 15 is in the recess. It is transferred cleanly onto the primer layer 2 away from the substrate to become a conductive material composition layer 3 ′. As shown in FIGS. 5 and 6, the peeling is performed by a nip roll 67 provided on the outlet side. Note that the conductive material composition 15 is not necessarily cured in the transfer step, and can be transferred even when the conductive material composition 15 contains a solvent. The reason for this is unknown at present, but the adhesion between the primer layer 2 cured in a closely adhered state without any gap and the conductive material composition 15 is such that the inner wall of the concave portion 64 of the intaglio roll and the conductive material composition. This is presumably because it is larger than the adhesion force between 15.

FIG. 7 is a schematic view showing a form in which the primer layer 2 is filled in the recess 6 of the conductive material composition 15 in the recess 64 and the conductive material composition 15 is transferred. As shown in FIG. 7C, when the form of the primer layer 2 after the transfer step and the form of the conductive material layer 3 ′ are observed, the portion of the primer layer 2 where the conductive material layer 3 ′ is transferred is shown. The thickness T _A is larger than the thickness T _{B of the} portion B where the conductive material layer 3 ′ is not transferred. In the side edges 5 and 5 of the portion A having a large thickness, the conductive material layer 3 wraps around the portion B having a small thickness. 7A and 7B show the primer layer 2 side of the transparent base material 1 on which the primer layer 2 retaining fluidity is formed and the concave portion 64 side of the plate surface 63 after the resin filling step. Since the primer layer 2 having fluidity is filled in the recesses 6 that are likely to be formed above the conductive material composition in the recesses 64, the form after the transfer is as shown in FIG. 7C. Of the primer layer 2 provided on the transparent substrate 1, the thickness T _A of the portion A where the conductive material layer 3 is formed is the thickness T _{B of the} portion B where the conductive material layer 3 is not formed. Further, the side edges 5 and 5 of the portion A having a large thickness are in a form in which the conductive material layer 3 wraps around the portion B having a small thickness. Usually, the thickness T _A of the primer layer in the portion A where the convex mesh pattern layer is formed becomes thicker toward the center of the portion as shown in FIG. That is, in the cross section of the electromagnetic wave shielding pattern portion (for example, FIG. 3), the cross-sectional shape of the primer layer 2 is a semicircle, a semi-ellipse, or the like that is convex toward the direction away from the transparent substrate 1. The so-called bell-shaped shape, the triangular shape, the trapezoidal shape, the pentagonal shape such as a pentagonal shape, or the like is formed.
The electromagnetic wave shielding material of the present invention is particularly characterized by the interface between the primer layer and the convex mesh pattern layer in the convex mesh pattern layer forming portion.

[Cross-sectional form of the interface between the convex mesh pattern layer and the primer layer]
The interface between the convex mesh pattern layer 3 and the primer layer 2 made of the conductive composition according to the present invention can take three cross-sectional forms as shown in FIGS. 9 (A) to (C). (A) A cross-sectional configuration in which the interface between the primer layer 2 and the convex mesh pattern layer 3 is non-linearly interlaced (hereinafter referred to as “first mode”). (B) a cross-sectional configuration having a layer in which the component constituting the primer layer 2 and the component constituting the convex mesh pattern layer 3 are mixed (hereinafter referred to as “second mode”), and (c) convex Cross-sectional form in which the components contained in the primer layer 2 are present in the conductive composition constituting the mesh pattern layer 3 (hereinafter referred to as “third aspect”, and the cross-sectional form is also referred to as “interface form”). ) Is adhesiveness, transferability of conductive composition It has given a favorable result.

As shown in FIG. 9A, the first mode of the interface form is that the interface 11 between the primer layer 2 and the convex mesh pattern layer 3 is alternately arranged on the primer layer 2 side and the convex mesh pattern layer 3 side. It is a non-linear form.
In the first aspect of this interface configuration, the complicated interface has a mountain-shaped cross-sectional configuration with a high center as a whole.

  In the first aspect of such an interface form, in addition to the fact that the convex mesh pattern layer 3 is formed on the mountain-shaped primer layer 2 which is not a flat surface in the first place, the above-mentioned adhesion is good, Thus, since the interface 11 is intricately formed, the adhesion between the primer layer 2 and the convex mesh pattern layer 3 is remarkably increased due to the so-called anchoring effect. Furthermore, because of such an interface form, the conductive composition filled in the plate recess is transferred to the primer layer 2 with a very high transfer rate (approximately 100%).

  As shown in FIG. 9 (B), the second form of the interface form is that the primer component contained in the primer layer and the convex mesh pattern layer are in the vicinity of the interface 11 between the primer layer 2 and the convex mesh pattern layer 3. The area | region 21 with which the component which comprises is mixed exists. Although the interface appears clearly in FIG. 9B, in reality, an unclear and ambiguous interface appears. In FIG. 9B, the mixed region 21 exists so as to sandwich the interface 11 vertically. In this case, the primer component in the primer layer and the arbitrary component in the convex mesh pattern layer 3 penetrate into each other. In addition, the mixing area | region 21 may exist in the upper side (opposite side to a transparent base material) of the interface 11, or may exist in the lower side (transparent base material side). The mixed region 21 exists above the interface 11 when the primer component in the primer layer penetrates into the convex mesh pattern layer and the component in the convex mesh pattern layer does not penetrate into the primer layer. On the other hand, when the mixed region 21 exists below the interface 11, any component in the convex mesh pattern layer penetrates into the primer layer, and the primer component in the primer layer enters the convex mesh pattern layer. It is a case where it does not enter.

  The second aspect of such an interface form has good adhesion even if the convex mesh pattern layer 3 is formed on the mountain-shaped primer layer 2 which is not a flat surface in the first place. As described above, since the mixed region 21 is provided in the vicinity of the interface 11, the adhesion between the primer layer 2 and the convex mesh pattern layer 3 is remarkably increased. Furthermore, because of such an interface form, the conductive composition filled in the plate recess is transferred to the primer layer 2 with a very high transfer rate (approximately 100%).

  A third aspect of the interface form is a form in which the primer component 31 included in the primer layer 2 exists widely in the convex mesh pattern layer 3 as shown in FIG. 9C. In FIG. 9C, the primer component 31 is increased in the vicinity of the interface 11 and decreased toward the top, and the mode is schematically shown. However, the mode is not particularly limited. The primer component 31 may penetrate into the convex mesh pattern layer 3 to the extent that it is detected from the top of the convex mesh pattern layer 3, or may be detected mainly in the vicinity of the interface. In the third aspect, in particular, when the region where the primer component 31 is present in the convex mesh pattern layer is localized in the vicinity of the interface 11, the mixed region is the interface 11 of the second aspect. It can be said that it corresponds to a form existing only on the upper side.

  As in the case of the first and second modes, the third mode of such an interface mode is because the convex mesh pattern layer 3 is formed on the mountain-shaped primer layer 2 that is not a flat surface. In addition to the good adhesion, since the primer component 31 penetrates into the convex mesh pattern layer 3 as described above, the adhesion between the primer layer 2 and the convex mesh pattern layer 3 is remarkably high. . Furthermore, because of such an interface form, the conductive composition filled in the plate recess is transferred to the primer layer 2 with a very high transfer rate (approximately 100%).

  The interface 11 between the convex mesh pattern layer 3 and the primer layer 2 made of the conductive composition in the present invention has at least one of the features of the interface form of the first to third aspects described above. May have two or more, and may have all three.

[Step difference between first direction line part and second direction line part of convex mesh pattern layer]
In the convex mesh pattern layer, line portions composed of two or more groups of parallel lines having different directions intersect each other, and are surrounded by these line portions to form an opening. Even when three or more parallel line groups (line parts) cross, the basic design points and operational effects are the same. I will explain. In addition, the crossing angle of each line group, that is, the crossing angle θ between the first direction line part and the second direction line part can be selected from the range of 0 ° <θ <180 °. A case where θ = 90 ° is used will be described as an example. For example, in an orthogonal mesh-shaped convex mesh pattern layer, as shown as an enlarged explanatory diagram in FIGS. 10A and 10B, from a group of parallel lines that run in a number of first directions made of the conductive composition 3. A convex mesh pattern of a square lattice is formed by the intersection of the first direction line portion L1 formed and the second direction line portion L2 formed of parallel lines running in the second direction. In many cases, there is a difference between the height of the first direction line portion L1 and the height of the second direction line portion L2, that is, a step ΔH. This depends on the difference between the groove-shaped concave portions corresponding to the respective line portions on the intaglio surface, that is, the step depth Δh of the plate depth when the intaglio plates corresponding to the first direction line portion and the second direction line portion are produced. . That is, it can be said that it depends on the processing accuracy of the intaglio plate depth.
In the present invention, the step ΔH between the first direction line portion and the second direction line portion of the convex mesh pattern layer after curing needs to be less than 0.5 μm.
When ΔH is 0.5 μm or more, the plate and the base material (primer and conductive composition) are peeled and charged when released from the intaglio, and a difference proportional to ΔH occurs in the charge amount. On the detached uncured conductive composition, a whisker-like object (fine needle-like protrusion) W is generated in the direction of the opening as shown in FIG.
Therefore, it is essential to use an intaglio plate having a plate-like or cylindrical plate surface in which the concave portion has a predetermined pattern and the step depth Δh between the first direction line portion and the second direction line portion is less than 0.5 μm. Yes, Δh is preferably closer to 0 μm.
In order to obtain an intaglio with little difference in plate depth corresponding to the first direction line portion and the second direction line portion, cutting with a cutting tool is preferable.
The step ΔH of the uncured conductive composition transferred in this way is a problem because the convex mesh pattern layer of the present invention has a conductive composition filled in the plate concave portion as described above. Is transferred onto the primer layer 2 with an extremely high transfer rate (almost 100%). Therefore, in consideration of productivity, economy, etc., when transferring an uncured state to form a conductive pattern, This is an extremely important matter although it is a case of a specific method for producing an electromagnetic shielding material.

[Metal layer]
In the electromagnetic wave shielding material of the present invention, when only the convex mesh pattern layer 3 made of a conductive composition is insufficient for desired conductivity, a metal layer is formed as necessary in order to further improve the conductivity. It can be formed on the convex mesh pattern layer 3 by plating. As plating methods, there are methods such as electrolytic plating and electroless plating, but electroplating can increase the plating rate several times by increasing the amount of current compared to electroless plating, which significantly improves productivity. This is preferable.
In the case of electrolytic plating, power is supplied to the convex mesh pattern layer 3 from an electrode such as an energizing roll brought into contact with the surface on which the convex mesh pattern layer 3 is formed, but the convex mesh pattern layer 3 can be electroplated. Since it has a certain degree of conductivity (for example, 100Ω / □ or less), electrolytic plating can be performed without any problem. Examples of the material constituting the metal layer include copper, silver, gold, chromium, nickel and the like, which have high conductivity and can be easily plated.
Since the metal layer generally has a volume resistivity smaller than that of the convex mesh pattern layer 3 by an order of magnitude or more, the amount of the conductive material required is larger than when the convex mesh pattern layer is used to ensure electromagnetic wave shielding. There is an advantage that can be reduced.

  Note that after the metal layer is formed, the metal layer may be blackened or a protective layer may be provided as necessary. Examples of the blackening treatment include blackening nickel plating, copper-cobalt alloy plating, and the like, and the protective layer is filled with irregularities of the convex mesh pattern layer separately from the flattening layer, and the surface is flattened. Rather, it is a layer that simply covers and protects the surface of the convex mesh pattern layer. For example, it can be formed using an acrylic photocurable resin. When the metal used for the convex mesh pattern layer or metal layer is a metal that easily rusts, such as copper, it is preferable to carry out a rust prevention treatment, and a general rust prevention agent can be used, and the rust prevention treatment is a blackening treatment. It may also serve as protective layer formation.

[Optical filter]
The electromagnetic wave shielding material obtained in this manner can be used as an optical filter having both an electromagnetic wave shielding function and an optical function by providing an optical adjustment layer. As the optical adjustment layer, a conventionally known layer may be used as it is, and examples thereof include a near infrared absorption layer, a neon light absorption layer, an ultraviolet absorption layer, an antireflection layer, and an antiglare layer. If necessary, the optical filter can be further combined with a layer that exhibits a function other than the optical function. Examples of such a layer include an impact resistant layer, an antistatic layer, a hard coat layer, and an antifouling layer.
Here, when an optical adjustment layer such as an antireflection layer is directly formed on the transparent base material on which the convex mesh pattern layer is formed, the antireflection layer is formed by the unevenness of the convex mesh pattern layer and the (primer layer coating) transparent base material. As a result, the coating unevenness and the mixing of bubbles occur, the bubbles scatter image light, resulting in a decrease in image quality, and the antireflection effect is insufficient. In order to solve this problem, a transparent flattening layer is provided to fill the unevenness between the convex mesh pattern layer and the (primer layer coating) transparent substrate, and an optical layer such as an antireflection layer is provided on the top surface. It is preferable to provide an adjustment layer. In addition, a near-infrared absorber, a neon light absorber, an ultraviolet absorber, etc. can also be added to resin used for a planarization layer.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.

An electromagnetic shielding material was manufactured by the apparatus shown in FIG.
[Preparation of intaglio]
First, as the intaglio roll 62, a concave portion that becomes a grid-like mesh pattern having a line width of 20 μm, a line pitch of 300 μm, and a target plate depth of 10 μm is formed in a first direction (circumferential direction of the intaglio roll) by a cutting tool. And intaglio rolls A, B, and C having a plate surface 63 on which a line portion perpendicular to the second direction (width direction of the intaglio roll) was formed were prepared. Next, an impression material made of silicon resin is filled into the concave portion 64 of the intaglio roll, and after hardening and solidified, it is peeled off from the intaglio plate to measure the height from the plate peripheral surface according to the direction, and the convex shape on the intaglio roll. For the groove-shaped recess corresponding to the mesh pattern, the step Δh between the first direction line portion and the second direction line portion was determined in units of 0.1 μm. The results are shown in Table 1.

[Preparation of transparent substrate]
Next, as the transparent substrate 1, a long roll-wrapped polyethylene terephthalate (PET) film having a width of 1000 mm and a thickness of 100 μm that was subjected to an easy adhesion treatment on one side was used. The PET film set in the supply part was drawn out, and a photocurable resin composition for the primer layer was applied and formed on the easy adhesion treatment surface so as to have a thickness of 5 μm. The application method employs a normal gravure reverse method, and the photocurable resin composition includes 35 parts by weight of an epoxy acrylate prepolymer, 12 parts by weight of a urethane acrylate prepolymer, and 44 parts by weight of a monofunctional monomer composed of phenoxyethyl acrylate. 9 parts by weight of trifunctional monomer composed of ethylene oxide-modified isocyanuric acid triacrylate, and further 3 parts by weight of Irgacure 184 (substance name: 1-hydroxy-cyclohexyl-phenyl-ketone, manufacturer: Ciba Specialty Chemicals) as a photoinitiator What added 2 weight part of modified silicone lithium salt as an antistatic agent was used for what was added. The viscosity at this time was about 150 cps (at 25 ° C., B-type viscometer), and the primer layer after application showed fluidity when touched, but did not flow down from the PET film.

Example 1, Comparative Examples 1 and 2
Next, as the intaglio roll 62, the primer layer 2 made of a photo-curing resin was formed using the above-described three types of intaglio A (Example 1), B (Comparative Example 1), and C (Comparative Example 2). The PET film is sandwiched between the intaglio roll 62 and the nip roll 66 with the primer layer 2 facing the plate surface 63 side of the intaglio roll 62. The primer layer 2 of the PET film is pressed against the plate surface 63 between the intaglio roll 62 and the nip roll 66. Since the primer layer 2 has fluidity, the primer layer 2 pressed against the plate surface 63 also flows into the recess 64 filled with the conductive composition 15, and the conductive material composition generated in the recess 64 is formed. The recess 6 of the object 15 is filled. Thus, the primer layer 2 is in close contact with the conductive composition 15 without any gap. Thereafter, the intaglio roll 62 was further rotated to irradiate ultraviolet rays with a high-pressure mercury lamp, and the primer layer 2 made of the ionizing radiation curable resin composition was cured.
In addition, as such a conductive composition, 93 parts by weight of scaly silver powder having an average particle diameter of about 2 μm as a conductive powder, 7 parts by weight of a thermoplastic polyester urethane resin as a binder resin, and 25% by weight of butyl carbitol acetate as a solvent After mixing the parts and sufficiently stirring and mixing, a product prepared by kneading with three rolls was used.
Due to the curing of the primer layer 2, the conductive composition in the recess 64 of the intaglio roll 62 comes into close contact with the primer layer 2, and then the film is peeled from the intaglio roll 62 by the nip roll 67 on the outlet side. A conductive material layer 3 ′ was transferred and formed. The transfer film thus obtained was passed through a drying zone at 110 ° C. to evaporate the solvent of the silver paste, thereby forming a convex mesh pattern layer 3 composed of a mesh pattern on the primer layer 2. At this time, the thickness of the convex mesh pattern layer 3 (thickness difference between the mesh pattern portion where the convex mesh pattern layer 3 is formed and the other portion) is set to each of the first direction line portion and the second direction line portion. As a difference between the two, a step ΔH between the first direction line portion and the second direction line portion of the convex mesh pattern layer was obtained in units of 0.1 μm. In both Example 1 and Comparative Examples 1 and 2, the thickness (height) of the convex mesh pattern averaged for the first direction line part and the second direction line part is about 9 μm, and the silver in the concave part 64 of the plate The paste was transferred with a high transfer rate (about 90%). Moreover, neither disconnection nor shape defect was seen.

[Evaluation of whiskers]
The state of occurrence of the whiskers in the electromagnetic shielding material obtained by the intaglios A, B, and C was observed. The results are shown in Table 1.

  As described above, in Example 1 using the intaglio A having a plate depth step Δh of 0.0 μm between the first direction line portion and the second direction line portion, the step ΔH of the obtained convex mesh pattern layer is also 0.0 μm. In this case, there was almost no generation of whiskers toward the opening, which was excellent as an electromagnetic shielding material. Further, it can be seen that when the step ΔH of the convex mesh pattern layer exceeds 0.5 μm, the generation of the whiskers becomes remarkable.

It is a typical top view which shows an example of the electromagnetic wave shielding material of this invention. It is an enlarged view of the A-A 'cross section in FIG. It is typical sectional drawing which expands and shows a part of FIG. It is process drawing which shows an example of the manufacturing method of the electromagnetic wave shield of this invention. It is a schematic block diagram of the apparatus which enforces the manufacturing method of this invention. It is a schematic block diagram of the apparatus which implements the transfer process which transcribe | transfers an electroconductive material composition on a primer layer. It is a schematic diagram which shows the form which fills the dent of the electroconductive material composition in a recessed part with a primer layer, and the electroconductive material composition transfers. It is explanatory drawing of the conventional phenomenon which the non-transfer part of an electroconductive ink composition generate | occur | produces on a transparent base material. It is typical sectional drawing of the interface form of a convex mesh pattern layer and a primer layer, (A) Interface form is a 1st aspect, (B) Interface form is a 2nd aspect, (C) Interface form is a 3rd aspect. Indicates. It is the front view of (A) perspective view and (B) (A) explaining the level | step difference (DELTA) H of the 1st direction line part and 2nd direction line part of a convex mesh pattern layer. It is explanatory drawing of the mustache-like thing produced on the convex-shaped mesh pattern layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent base material 2 Primer layer 3 Convex mesh pattern layer (3 'electroconductive material composition layer)
DESCRIPTION OF SYMBOLS 4 Metal layer 5 Side edge 6 Recess 7 Electromagnetic wave shielding pattern part 8 Grounding part 9 Protective layer 10 Electromagnetic wave shielding material 15 Conductive material composition 51 Gravure roll 52 Backup roll 53 Resin composition filling container 54 Doctor blade 61 Pickup roll 62 Intaglio roll 63 ed surface 64 recess 65 a doctor blade 66 nip roll 67 a nip roll 68 cartridge a conductive material layer is thick in the thickness B conductive material layer is not formed part T _B B portion T _a a formed L1 first One-direction line part L2 Second-direction line part W Bearded object

Claims (2)

An electromagnetic shielding material having a transparent substrate, a primer layer formed on the transparent substrate, and a convex mesh pattern layer made of a conductive composition formed in a predetermined pattern on the primer layer,
Of the primer layer, the portion where the convex mesh pattern layer is formed is thicker than the portion where the convex mesh pattern layer is not formed, and the convex mesh pattern layer is formed. The interface between the primer layer and the convex mesh pattern layer in the part is (a) a cross-sectional configuration in which the interface between the primer layer and the convex mesh pattern layer is in a non-linear manner, and (b) constitutes the primer layer And a cross-sectional form having a layer in which the component constituting the convex mesh pattern layer is mixed, and (c) contained in the primer layer in the conductive composition constituting the convex mesh pattern layer The convex mesh pattern layer has a flat surface running in each of a first direction and a second direction different from each other. A first direction line portion and a second direction line portion formed of a line group are configured to cross each other, and a step ΔH between the first direction line portion and the second direction line portion is less than 0.5 μm. Electromagnetic shielding material.   The electromagnetic wave shielding material according to claim 1, wherein a metal layer is further formed on the surface of the convex mesh pattern layer.

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