JP2011134869A - Electromagnetic shielding material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic shielding material having a satisfactory electromagnetic shielding characteristics and capable of achieving a thin line width of, for instance, ≤20 μm, especially ≤10 μm in a convex pattern layer. <P>SOLUTION: The electromagnetic shielding material 10 has a transparent base material 1, and a convex pattern layer 2 comprising a conductive composition formed on the transparent base material 1. The conductive composition includes a conductive particles 4 having an average particle size of 1/4 or below of the line width W of the convex pattern layer 2 and a binder resin 5, and grain aggregation 3 mutually contacting with sixteen or more conductive particles 4 at the horizontal cutting cross-section of the convex pattern layer 2. Preferably, the grain aggregations 3 may have a structure in which at least four-by-four conductive particles 4 mutually contact. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electromagnetic wave shielding material, and more particularly, to an electromagnetic wave shielding material having good electromagnetic wave shielding characteristics, having a lump portion where conductive particles contact each other in a convex pattern layer.

  As an image display device (also referred to 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 electroluminescent (EL) display Devices 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.

  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. The electromagnetic shielding material described in Patent Document 2 forms a mesh pattern by intaglio offset printing, so that a fine pattern can be formed. However, since offset printing is adopted, transfer from the intaglio to a transfer body (blanket cylinder) is possible. After that, the second transfer is performed from the transfer body to the transparent substrate, and the intaglio mesh pattern as the original plate may not be faithfully transferred to the transparent substrate.

  In addition, the electromagnetic shielding material described in Patent Document 3 is a system in which a conductive ink composition is directly transferred from an intaglio to a transparent substrate, so there is no problem of pattern distortion due to a blanket cylinder peculiar to offset printing, and a silk screen Although a fine pattern can be formed compared to printing, it is necessary to transfer a conductive ink having poor fluidity at a high coating amount (also referred to as transfer), and as a new problem, the conductive ink is transferred. In some cases, an untransferred portion may occur or a transfer defect having poor adhesion may occur. Actually, the transition rate is limited to about 20% at the maximum, and it has been difficult to obtain a sufficient electromagnetic shielding property.

  As a means for solving the above problems, the present applicant press-bonded a transparent base material provided with a semi-fluid primer layer made of an ultraviolet curable resin and an intaglio filled with a conductive composition, and then cured. Thus, an electromagnetic wave shielding material in which a conductive convex pattern layer is formed at an extremely high transfer rate and a manufacturing method thereof are proposed (Patent Document 4).

JP 11-170420 A JP 2001-102792 A Japanese Patent Laid-Open No. 11-174174 WO2008 / 149969 A1 (International pamphlet) JP 2006-313891 A

  In the process of further studying the invention described in Patent Document 4, the present inventor has a higher electromagnetic wave shielding property due to the electromagnetic wave shielding material if the resistance of the conductive convex pattern layer can be further reduced. The present inventors have found a problem that it can be applied and that the line width of the convex pattern layer can be further reduced.

  The present invention has been made in order to solve the above-mentioned problems, and its object is to have a good electromagnetic shielding characteristic and to enable the thinning of the convex pattern layer to a line width of, for example, 20 μm or less, particularly 10 μm or less. The object is to provide an electromagnetic shielding material.

  The electromagnetic wave shielding material according to the present invention for solving the above-mentioned problems has a transparent substrate and a convex pattern layer made of the conductive composition formed on the transparent substrate, and the conductive composition Includes conductive particles having an average particle diameter of 1/4 or less of the line width of the convex pattern layer and a binder resin, and at least one transverse cut surface of the convex pattern layer has 16 or more The conductive particles have a lump portion in contact with each other.

  According to this invention, the conductive composition containing conductive particles having a mean particle diameter of 1/4 or less of the line width of the convex pattern layer and the binder resin is at least one of the convex pattern layers. Since 16 or more electroconductive particles have a lump part which mutually contacts in a horizontal cut surface, a low resistance convex pattern layer can be implement | achieved by the lump part, and an electromagnetic wave shielding characteristic can be improved. As a result, the wiring width of the convex pattern layer can be further reduced.

  In the electromagnetic wave shielding material according to the present invention, it is preferable that the lump part is in contact with the conductive particles at least 4 × 4 horizontally.

  According to the present invention, since the agglomerates are in contact with each other with at least 4 × 4 conductive particles, the convex pattern layer is thinned to a line width of, for example, 20 μm or less, particularly 10 μm or less. Can do.

  In the electromagnetic wave shielding material according to the present invention, the distribution of the conductive particles in the convex pattern layer is relatively sparse on the transparent substrate side, and has the lump on the side away from the transparent substrate. And relatively dense. In this invention, the sparsely distributed regions have conductive particles present in the binder resin without contacting each other.

  According to this invention, the distribution of the conductive particles in the convex pattern layer is relatively sparse on the transparent substrate side, and has a lump on the side away from the transparent substrate, and is relatively dense. Therefore, regardless of the size ratio of the lump portion relative to the transverse cut area of the convex pattern layer, even if the lump area ratio is small, the lump portion composed of a limited amount of conductive particles is present. In the vicinity of the top of the convex pattern layer (side away from the transparent substrate), it exists as a low-resistance conducting portion. As a result, the electromagnetic wave shielding characteristics by the convex pattern layer can be enhanced, and the line width of the convex pattern layer can be further reduced. On the other hand, since the conductive particles are sparse on the transparent substrate side, the ratio of the binder resin is large on the transparent substrate side, and the convex pattern layer and the transparent substrate (the primer layer is provided on the transparent substrate). In this case, the adhesion to the primer layer is increased, and peeling and detachment of the convex pattern layer can be suppressed. According to the present invention, since the conductive particle distribution on the transparent substrate side of the convex pattern layer is sparse, it is possible to reduce the influence (reflection of light, etc.) of the conductive particles present in such a part. In the case where the surface side where the distribution of the conductive particles is sparse is directed to the outside light side (observer side), it is possible to prevent the whitening of the image and the decrease in contrast due to the outside light, while the distribution of the conductive particles When the sparse surface side is directed to the image display device side, whitening of the image and a decrease in contrast due to reflection of image light on the screen can be prevented.

  In the electromagnetic wave shielding material according to the present invention, the convex pattern layer has a surface resistivity of 10Ω / □ or less.

  According to the present invention, since the convex pattern layer has a surface resistivity of 10Ω / □ or less, it has a preferable electromagnetic wave shielding characteristic as an electromagnetic wave shielding material, and further has the surface resistivity. Electroplating can be easily performed on the top, and electromagnetic wave shielding characteristics can be further enhanced.

  In the electromagnetic wave shielding material according to the present invention, the transparent substrate surface on the side where the convex pattern layer is provided has a primer layer, and the thickness of the portion of the primer layer where the convex pattern layer is formed This is thicker than the thickness of the portion where the convex pattern layer is not formed.

  According to this invention, since the primer layer for providing the convex pattern layer with better adhesion is provided as the underlayer of the convex pattern layer, the convex pattern layer can be formed with good adhesion, and the convex pattern layer is peeled off. And desorption can be suppressed. Furthermore, the thickness of the portion of the primer layer where the convex pattern layer is formed is formed to be thicker than the thickness of the portion where the convex pattern layer is not formed. However, the convex pattern layer on the primer layer can be held with better adhesion.

  According to the present invention, the conductive composition containing conductive particles having a mean particle diameter of ¼ or less of the line width of the convex pattern layer and the binder resin is at least one of the convex pattern layers. Since 16 or more electroconductive particles have a lump part which mutually contacts in a horizontal cut surface, a low resistance convex pattern layer can be implement | achieved by the lump part, and an electromagnetic wave shielding characteristic can be improved. As a result, it is possible to achieve further thinning of the wiring width of the convex pattern layer while exhibiting electromagnetic wave shielding characteristics.

It is a typical top view which shows an example of the electromagnetic wave shielding material which concerns on this invention. It is an expanded sectional view showing an example of a convex pattern layer. It is an expanded sectional view showing other examples of a convex pattern layer. It is an expanded sectional view showing other examples of a convex pattern layer. It is typical sectional drawing which shows the example of the form of the lump part of the electroconductive particle in the convex pattern layer which comprises this invention. It is typical sectional drawing which shows the form example of the lump part of the electroconductive particle in the convex pattern layer which does not comprise this invention. It is explanatory drawing which shows states, such as a contact of adjacent electroconductive particles. It is typical sectional drawing of the interface of a convex pattern layer and a primer layer, (A) is the 1st section form, (B) is the 2nd section form, and (C) is the 3rd section form. It is a cross-sectional form. It is a schematic diagram which shows the form which fills the recessed part of the electroconductive composition in a recessed part with a primer layer, and the electroconductive composition transfers. It is a schematic block diagram which shows an example of the manufacturing apparatus of an electromagnetic wave shielding material. It is a schematic block diagram which shows another example of the manufacturing apparatus of an electromagnetic wave shielding material.

  Next, embodiments of the electromagnetic wave shielding material according to the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist. .

[Electromagnetic wave shielding material]
As shown in FIGS. 2 to 4, the electromagnetic wave shielding material 10 (10 </ b> A to 10 </ b> C) according to the present invention includes a transparent substrate 1 and a convex pattern layer made of a conductive composition formed on the transparent substrate 1. 2. The convex pattern layer 2 may be provided directly on the transparent substrate 1 (see FIG. 2), or may be provided on the primer layer 6 provided on the entire surface of the transparent substrate 1. Further, a metal layer 8 may be provided on the convex pattern layer 2 (see FIG. 4).

  The convex pattern layer 2 is a conductive pattern formed in a predetermined pattern, and is commonly used as an electromagnetic shielding pattern, such as a mesh (mesh or lattice), stripe (parallel line group or stripe), spiral (or Is a spiral shape or a line segment group pattern. Further, as shown in FIG. 1, the electromagnetic wave shielding material 10 has an electromagnetic wave shielding pattern portion 11 that is located at the center and faces the image display area of the display device, and at least a peripheral portion of the electromagnetic wave shielding pattern portion 11. A part (preferably the entire circumference) has a grounding portion 12.

  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 (light transmittance) in the visible light region, heat resistance, and mechanical strength. Such a transparent substrate 1 may be a rigid plate-like body such as a plate made of a transparent inorganic material such as glass or ceramics or a plate made of a transparent resin material, but is a roll-to-roll having excellent productivity. Considering the suitability for continuous processing, a flexible film (or sheet) made of a resin material is preferable. The roll-to-roll refers to a processing method in which the material is unwound from a winding (roll) and supplied, subjected to desired processing (manufacture of an electromagnetic wave shielding material), and then wound on the winding.

  Examples of the resin material of the transparent substrate 1 include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), ethylene glycol-1,4 cyclohexanedimethanol-terephthalic acid copolymer, ethylene glycol-terephthalic acid-isophthalic acid copolymer. Polymers, polyester resins such as polyester thermoplastic elastomers; acrylic resins such as polymethyl methacrylate; polyolefin resins such as polypropylene and cycloolefin polymers; cellulose resins such as triacetyl cellulose; polycarbonate resins; PI) resin; and the like. Among these, a biaxially stretched film of polyethylene terephthalate is preferable in terms of heat resistance, mechanical strength, light transmittance, cost, and the like. Examples of the inorganic material include soda glass, potassium glass, borosilicate glass, lead glass, and other transparent ceramics such as PLZT, quartz, and the like.

  There is no restriction | limiting in particular in the thickness of the transparent base material 1, It can select suitably according to a use etc. For example, the thickness when a flexible resin film is used as the transparent substrate 1 is, for example, about 12 to 500 μm, preferably about 25 to 200 μm. Moreover, the thickness when the board | substrate of a resin material or an inorganic material is used as the transparent base material 1 is about 500-5000 micrometers, for example. The transparent substrate 1 may be subjected to a surface treatment for providing the following convex pattern layer 2 or primer layer 6 with good adhesion, or may be provided with an easy adhesion layer or a base layer. Examples of the surface treatment include corona discharge treatment, plasma treatment, and flame treatment. Moreover, as an easily bonding layer, resin layers, such as a urethane resin, an epoxy resin, a polyester resin, an acrylic resin, a chlorinated polypropylene, can be mentioned.

(Convex pattern layer)
The convex pattern layer 2 is provided in a predetermined pattern on the transparent substrate 1 as shown in FIGS. FIG. 2 is an example in which the convex pattern layer 2 is directly provided on the transparent substrate 1, and FIG. 3 is an example in which the convex pattern layer 2 is provided on the primer layer 6 provided on the entire surface of the transparent substrate 1. It is an example provided. Here, the “predetermined pattern” is typically a mesh (mesh or lattice) shape, but other examples include a stripe (parallel line group or stripe pattern) shape, a spiral shape, and the like. Examples of the unit cell shape in the case of a mesh-shaped pattern include triangles such as regular triangles and inequilateral triangles, squares such as squares, rectangles, trapezoids, and rhombuses, polygons such as hexagons and octagons, circles, ellipses, and the like. It is done. Further, for the purpose of reducing moire, a random mesh pattern or a pseudo-random mesh pattern may be used.

  The line width W and the line-to-line pitch of the convex pattern layer 2 up to now are a line width W: 20 to 50 μm and a line-to-line pitch: 100 to 500 μm. Particularly in recent image display devices, good electromagnetic wave shielding characteristics In order to improve transparency, further thinning is required. In the electromagnetic wave shielding material 10 according to the present invention, the line width W of the convex pattern layer 2 is 20 μm or less, preferably 10 μm or less. More specifically, the line width W is 5 to 20 μm, preferably 5 μm to 10 μm.

  Here, the line width W is the width in the cross section of the convex pattern layer 2 as shown in FIGS. 2 and 3, and the metal layer 8 is formed on the convex pattern layer 2. Even in this case, the width in the cross section of the convex pattern layer 2 (not including the metal layer 8). Note that the shape of the convex pattern layer 2 on the transverse cut surface is usually in the height direction (also in the thickness direction as shown in FIG. 2 or FIG. 3, etc. In FIG. 2 or FIG. In many cases, the width changes along the line. The line width W in such a case is defined as follows in view of the fact that the present invention is important for the distribution and arrangement state of the conductive particles 4 in the convex pattern layer 2. That is, the lump 3 of the conductive particles 4 among various numerical values (functions of the position in the height direction) obtained as the length in the direction parallel to the transparent substrate surface on the transverse cut surface of the convex pattern layer 2. Is defined as “line width W” by a minimum value in a region where the region exists (region corresponding to the dense portion Q in FIGS. 5E and 5G).

  The aperture ratio of the electromagnetic wave shielding material 10 on which the convex pattern layer 2 is formed [occupation ratio of the opening portion (portion other than the convex pattern layer 2) in the electromagnetic wave shielding pattern portion 11] is usually about 75 to 99%. .

The height H (thickness T _C ) of the convex pattern layer 2 varies depending on the resistance value of the convex pattern layer 2, but from the surface (upper surface) of the transparent substrate 1 to the central portion ( It is represented by a height H (thickness T _C ) to the top of the convex pattern layer 2 and is usually 2 μm or more and 20 μm or less, preferably 5 μm or more and 10 μm or less. In addition, in the case shown in FIG. 2, the code | symbol H represents the height from the transparent base material 1 surface to the center part (top part of the convex pattern layer 2) of the convex pattern layer 2, Therefore, convex pattern It corresponds to the thickness T _{C of} layer 2. On the other hand, in the case shown in FIG. 3, the symbol H is from the standard surface of the primer layer 6 (the portion having a substantially constant thickness) to the central portion of the convex pattern layer 2 (the top portion of the convex pattern layer 2). represents the height, reference numeral T _C is raised part of the primer layer 6 is provided as a lower layer of the convex pattern layer 2 the central portion of the convex pattern layer 2 from the (top) 7 (the convex pattern layer 2 To the top). In this case, T _C <H.

  A feature of the present invention is that the conductive composition (also referred to as conductive ink or conductive paste) constituting the convex pattern layer 2 having a line width W in the above range is 1 in the line width W of the convex pattern layer 2. / 4 of conductive particles 4 having an average particle size of / 4 or less and binder resin 5, and at least one transverse cut surface of convex pattern layer 2 has 16 or more conductive particles 4 in contact with each other It is in having the lump part 3 to do. Here, the lump portion 3 in which 16 or more conductive particles 4 are in contact with each other is an aspect in which the conductive particles 4 are in contact with each other in at least 4 vertical × 4 horizontal. The “lateral cut surface” corresponds to, for example, a cut surface perpendicular to the extending direction when the convex pattern layer 2 has a wire hook portion extending in a specific direction.

  As the binder resin 5, any of thermosetting resin, ionizing radiation curable resin, and thermoplastic resin 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. be able to. Examples of the ionizing radiation curable resin include a primer layer forming material to be described later, and these can be used alone or in combination of two or more. When using an ionizing radiation curable resin, a photopolymerization initiator may be added as necessary. Examples of the thermoplastic resin include thermoplastic polyester resins, polyvinyl butyral resins, thermoplastic acrylic resins, thermoplastic polyurethane resins, vinyl chloride-vinyl acetate copolymers, and the like. Two or more kinds can be mixed and used. When using a thermosetting resin, you may add a curing catalyst as needed.

  Examples of the conductive particles 4 include particles of low resistivity metal such as gold, silver, platinum, copper, nickel, tin, and aluminum; surfaces of core material particles such as high resistivity metal particles, resin particles, and non-metallic inorganic particles. Examples thereof include particles coated with a low resistivity metal such as gold or silver; graphite particles; conductive polymer particles; conductive ceramic particles. The shape of the conductive particles 4 can be selected from a polyhedron shape such as a regular polyhedron shape and a truncated polyhedron shape, a spherical shape, a spheroid shape, a scale shape, a disc shape, a dendritic shape, and a fibrous shape. In particular, a polyhedral shape, a spherical shape, or a spheroid shape is preferable. These materials and shapes may be appropriately mixed and used.

  The size of the conductive particles 4 is specified by the average particle size. The average particle diameter is preferably a length of ¼ or less of the line width W of the convex pattern layer 2. For example, when the line width W is 20 μm, the average particle diameter of the conductive particles 4 is preferably 5 μm or less of 1/4 of 20 μm, and when the line width W is 10 μm, the conductive particles 4 The average particle size of 4 is preferably ¼ of 10 μm, 2.5 μm or less. In any case, the lower limit of the average particle diameter of the conductive particles 4 is preferably 1 μm. By using the conductive particles 4 having such an average particle diameter, at least four or more conductive particles 4 can be arranged in the line width direction of the convex pattern layer 2. When the average particle diameter is larger than the above value, at least four or more conductive particles 4 cannot be arranged in the line width direction of the convex pattern layer 2.

When the aspect ratio of the convex pattern layer 2 is expressed by “line width W / height H (thickness T _C )”, the aspect ratio is in the range of 1/2 to 8/1, preferably 1/1. It is in the range of ~ 3/1. In the present invention, also in the height direction (thickness direction) of the convex pattern layer 2, it is preferable to arrange at least four conductive particles 4 in the same manner as in the line width direction. Accordingly, as shown in FIGS. 2 to 5, the convex pattern layer 2 has a lump portion 3 in which 16 or more conductive particles 4 are in contact with each other on the transverse cut surface. It is preferable that at least one transverse cut surface of the convex pattern layer 2 has an aspect in which the conductive particles 4 are in contact with each other at least 4 × 4 in width.

  As a rule of thumb, if at least one transverse cut surface of the convex pattern layer 2 has the mass portion 3 of the above-described aspect, the conductive particles 4 in contact with each other in the mass portion 3 in the other transverse cut surface. Even if the number is 15 or less, the convex pattern layer 2 has a convex shape even in a direction orthogonal to the transverse cut surface (in the case where the convex pattern layer 2 is a wire rod pattern, the extending direction of the wire rod). There is a high probability that there is one or more paths through which the pattern layer 2 is continuously conducted from one end portion to the other end portion in the orthogonal direction (extending direction) of the electromagnetic wave shielding material. For example, referring to FIG. 1, each wire rod of the convex pattern layer 2 constituting the electromagnetic wave shield pattern portion 11 (two groups of wire rods cross each other to form a mesh) is from the left end to the right end, from the left end to the upper end, or It travels from the left end toward the lower end and connects between the ground contact portions 12 at both ends. In each of these wire rods, the conductive particles 4 that continue from the left end ground portion to the right end ground portion (the left end ground portion to the upper end ground portion, or the left end ground portion to the lower end ground portion). This means that there is a high probability that there is one or more paths through which current due to contact can flow. Therefore, it has been found that the conductivity of the convex pattern layer 2 and further the electromagnetic wave shielding property are practically sufficient.

The line width W and height H (thickness T _C ) of the convex pattern layer 2 having the mass portion 4 of the above aspect are at least four times the average particle diameter of the conductive particles 4. . And it is desirable that the aspect ratio is also a ratio (for example, 1/1 to 3/1) in which the mass portion 3 can exist as in the above-described range.

  Since the average particle diameter of the conductive particles 4 may be 1/4 or less of the line width W of the convex pattern layer 2 and 1 μm or more, the lump 3 is composed of 16 or more conductive particles 4. It does not matter. Specifically, as shown in FIG. 5, if there are at least 4 vertical × 4 horizontal, 5 × 4, 4 × 5, 6 × 4, 4 × 6, 5 It may be 5 × 5 pieces. Further, the arrangement is not particularly limited, and for example, as shown in FIGS. 5A and 5C, the arrangement may be in a state of being arranged vertically and horizontally in a mode of 4 × 4 and a mode of 5 × 5. Then, for example, as shown in FIGS. 5B and 5D, they may be arranged in the form of 4 × 4 and 4 × 5 in a vertically and horizontally close packed manner. In this way, since the lump portion 3 has at least 4 vertical particles × 4 horizontal conductive particles 4 in contact with each other, the convex pattern layer 2 has a line width W of, for example, 20 μm or less, preferably 10 μm or less. Thinning can be realized.

  The lump 3 is continuously connected in the direction in which the convex pattern layer 2 extends (also referred to as the extending direction). The lump portion 3 continuously connected in the extending direction exhibits a stable low resistance, but the stable low resistance can be realized by the lump portion 3 being in contact with 16 or more conductive particles 4, specifically As shown in FIGS. 5 (A) to 5 (E), this can be realized by contacting at least 4 × 4 conductive particles 4 with each other. As shown in FIGS. 6A to 6E, when the lump portion 3 is composed of less than 16 conductive particles 4, there may be cases where stable low resistance is not exhibited in the extending direction.

  The average particle diameter of the conductive particles 4 is evaluated by a value measured by a particle size distribution meter or TEM (transmission electron microscope) observation. When the conductive particles 4 are spherical, the average particle diameter is However, in the case of a polyhedron, it is the average of the diameter of the circumscribed sphere, and in the case of the spheroid, it is the average of the diameter in the major axis direction or the diameter of the circumscribed sphere, scaly, discoid, dendritic and fibrous Is the average of the diameter of the circumscribed sphere. The average particle size of each grain shape evaluated in this way is defined as the average particle size according to the present invention.

  Although content of the electroconductive particle 4 in an electroconductive composition is arbitrarily selected according to the shape and electroconductivity of the electroconductive particle 4, for example, among 100 mass parts of solid content of an electroconductive composition, it is electroconductive. The particles 4 are contained in the range of 90 to 99 parts by mass, preferably 92 to 98 parts by mass. By setting it as this range, when the conductive paste is dried, the conductive particles come into contact with each other with an appropriate amount of the binder resin 5 to be bound, and the lump portion 3 can be configured. If the content of the conductive particles 4 is less than 90 parts by mass, the binder resin 5 still contains a sufficient amount, so that the conductive particles 4 are sparsely distributed between the binder resins 5 to form the mass 3. Can not. On the other hand, when the content of the conductive particles 4 exceeds 99 parts by mass, the conductive particles 4 cannot be hardened by the action of the binder resin 5 and the binding of the conductive particles 4 to each other by the binder resin 5 becomes incomplete. Even if the convex pattern layer 2 becomes poorly formed in a predetermined shape, or even if it can be formed, it may be easily collapsed by an external force.

  The conductive composition has fluidity and is filled in the intaglio, but in the case of a conductive composition using a thermoplastic resin as a binder resin, a conductive paste or conductive ink containing a solvent is preferable. The kind of solvent is not specifically limited, It can select from the solvent used for general printing ink suitably, and can use it. For example, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and cyclopentanone; ethers such as methyl ether and ethyl ether; ethyl acetate, methyl butyl butyrate, acetic acid diethylene glycol-n-butyl ether, ethylene glycol monobutyl ether acetate Esters such as: Aliphatic hydrocarbons such as pentane, hexane, and octane; Aromatic hydrocarbons such as benzene, toluene, and xylene; Alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol, and terpineol 1 type or 2 types or more appropriately selected from the group: water; The content of the solvent is about 10% to 70% by weight of the entire composition for forming a transparent protective layer, but is preferably as small as possible within a range where necessary fluidity is obtained.

  However, as will be described later in the section of the production method, when the primer layer 6 is provided to further improve the transfer rate, the primer layer 6 is inhibited from stable curing or the cured primer layer 6 is swollen. Those which are not whitened or dissolved are preferred. 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. On the other hand, when an ionizing radiation curable resin is used, it does not necessarily require a solvent because it is inherently fluid.

  In addition, in order to improve the fluidity and stability of the conductive composition, as long as it does not adversely affect the conductivity and adhesion to the primer layer 6, a filler, a thickener, an antistatic agent, a surface activity An agent, an antioxidant, a dispersant, an anti-settling agent, etc. may be added.

  As shown in FIG. 4, a metal layer 8 to be described later may be provided on the convex pattern layer 2 by electroplating. For this purpose, the surface resistivity of the convex pattern layer 2 is preferably as low as possible. Specifically, the surface resistivity is preferably 10Ω / □ or less. When the surface resistivity is 10Ω / □ or less, power can be supplied to the convex pattern layer 2 and electroplating can be performed. The surface resistivity after metal plating is preferably 1.0Ω / □ or less, and more preferably 0.1Ω / □ or less. On the other hand, when the metal layer 8 is not provided on the surface of the convex pattern layer 2, the convex pattern layer 2 itself needs to have good electromagnetic wave shielding characteristics. For example, when the convex pattern layer 2 has a line width of 5 to 20 μm and a thickness of 5 to 20 μm, the surface resistivity of the convex pattern layer 2 is preferably 1.0Ω / □ or less. More preferably, it is 1Ω / □ or less.

  Thus, the conductive composition containing the conductive particles 4 and the binder resin 5 having an average particle diameter of 1/4 or less of the line width W of the convex pattern layer 2 is the convex pattern layer 2. Since the 16 or more electroconductive particles 4 have the lump part 3 which mutually contacts in a horizontal cut surface, it is possible to make the surface resistivity of the convex pattern layer 2 into 10 ohms / square or less, and by the lump part 3 The low resistance convex pattern layer 2 can be realized, and the electromagnetic shielding characteristics can be enhanced. As a result, the wiring width W of the convex pattern layer 2 can be further reduced.

  Next, the density distribution of the conductive particles in the convex pattern layer 2 will be described.

  As shown in FIGS. 5F and 5G, the distribution of the conductive particles 4 in the convex pattern layer 2 is relatively sparse on the transparent base material 1 side and lump on the side away from the transparent base material 1. It is preferable to have the portion 3 and be relatively dense. In this case, the densely distributed region Q is a region where the lump portion 3 where the conductive particles 4 are in contact with each other exists, and is the side away from the transparent substrate 1 (or primer layer 6), that is, a convex pattern layer. 2 near the top. On the other hand, the sparsely distributed region R is a region where there is no lump 3 where the conductive particles 4 are in contact with each other, and is closer to the transparent substrate 1 (or primer layer 6), that is, the convex pattern layer 2 It is near the bottom. In the sparse region R, as shown in FIGS. 5F and 5G, the ratio of the conductive particles 4 existing in a floating state in the binder resin without contacting each other is high.

  The ratio of the dense region Q and the sparse region R is about Q: R (10: 1 to 1: 1). The sparse region R may be present at a considerably smaller ratio than the dense region Q, but at least the presence of the sparse region R increases the adhesion with the material on the transparent substrate side, which is preferable. .

  Thus, the distribution of the conductive particles 4 in the convex pattern layer 2 is relatively sparse on the transparent base material 1 side, and has the lump portion 3 on the side away from the transparent base material 1. Even if the area ratio of the lump part 3 is small regardless of the area ratio of the lump part 3 with respect to the transverse cut area of the convex pattern layer 2, a limited amount of conductivity is added. The lump portion 3 composed of the particles 4 exists as a low-resistance conducting portion in the vicinity of the top portion of the convex pattern layer 2 (the side away from the transparent substrate 1). As a result, the electromagnetic wave shielding characteristics by the convex pattern layer 2 can be enhanced, and the line width W of the convex pattern layer 2 can be further reduced. On the other hand, since the conductive particles 4 are sparse on the transparent substrate 1 side, the ratio of the binder resin 5 is large on the transparent substrate 1 side, and the convex pattern layer 2 and the transparent substrate 1 (on the transparent substrate 1). In the case where the primer layer 6 is provided, the adhesion with the primer layer 6) is enhanced, and peeling and detachment of the convex pattern layer 2 can be suppressed.

  On the other hand, since the distribution of the conductive particles 4 on the transparent substrate side 1 of the convex pattern layer 2 is sparse, the influence (reflection of light, etc.) of the conductive particles 4 existing in the region R can be reduced. When the surface of the conductive particle 4 having a sparse distribution is directed to the external light side (observer side), whitening of the image and contrast reduction due to external light (electric light, sunlight, etc.) can be prevented. On the other hand, when the surface side where the distribution of the conductive particles 4 is sparse is directed to the image display device side, whitening of the image and contrast reduction due to reflection of image light on the screen (particularly specular reflection) can be prevented. There is also an effect that can be done.

  In order to express this effect more effectively, it is preferable to select conductive particles 4 having a polyhedral shape, a spherical shape or a spheroid shape rather than the scale-like conductive particles 4. It is possible to prevent a surface close to a mirror surface from being formed on the surface of the transparent substrate 1 side or the primer layer 6 side. On the other hand, when the scale-like conductive particles 4 are used, the orientation direction of the scale-like conductive particles in the convex pattern layer 2 (orientation direction: here, the normal direction of the widest surface of the scale is defined. ) In a random (random) manner is preferable because specular reflection can be reduced. In addition, even when the conductive particles 4 are polyhedral, spherical, or spheroid, it is preferable that the orientation direction is disordered, and specular reflection light can be reduced. In this case, since the conductive particles 4 facing the display surface side of the image display device exist as a densely-aggregated mass portion 3, the electrical contact between the particles is good and the electrical resistance is lowered. The electromagnetic shielding effect is high. The conductive particles 4 present as the high-density mass 3 have a high visible light reflectance, but the conductive particles 4 are not touched by the image observer (the display surface side opposite to the observer). ), The image contrast is not lowered.

  Contrary to the above case, when the electromagnetic wave shielding material 10 is arranged so that the convex pattern layer 2 side is directed to the observer side and the transparent substrate 1 side is directed to the display surface side of the image display device, it is necessary. Accordingly, the surface of the convex pattern layer 2 may be blackened.

  In order to obtain the sparse / dense distribution, for example, the depression 17 (see FIG. 9A) on the upper surface of the conductive composition 2 ′ filled in the concave portion 34 of the plate surface 33 used in a specific intaglio printing method described later. The pressure for pressing the fluidized primer layer 6 on the transparent substrate 1 is set high, the viscosity of the uncured conductive composition 2 'is set low, and the conductive composition 2' It is effective to solidify after releasing from the plate surface 33 without solidifying within the recess 34. In addition, the density distribution or orientation state of these conductive particles 4 depends on the type of the binder resin 5 of the conductive composition, the material and average particle diameter and particle shape of the conductive particles 4, and the binder resin 5 and the conductive particles 4. It depends on the blending ratio and the coating conditions or solidifying conditions of the conductive composition. Actually, conditions that match the desired density distribution and orientation of the conductive particles 4 are experimentally determined from various conditions that affect the density distribution or orientation state of the conductive particles 4.

  With the above configuration, (a) the conductive particles 4 constituting the conductive composition are relatively sparse in the vicinity of the interface of the convex pattern layer 2 on the transparent substrate 1 side (or the primer layer 6 side). Since it exists as a lump 3 near the top away from the transparent substrate 1 and is relatively dense, the lump 3 present near the top of the convex pattern layer 2 reduces the electrical resistance. As a result, even when the line width of the convex pattern layer 2 is reduced to 20 μm or less (preferably 10 μm or less), an increase in electrical resistance due to a decrease in cross-sectional area can be suppressed, and an increase in surface resistivity can be achieved. It is possible to provide an electromagnetic wave shielding material having good electromagnetic wave shielding characteristics by being suppressed. Further, (a) in the vicinity of the interface on the transparent substrate 1 side (or the primer layer 6 side), the conductive particles 4 are relatively sparse and the binder resin 5 is relatively large. Therefore, the transparent substrate 1 (transparent substrate 1 When the primer layer 6 is provided on the top, the adhesion to the primer layer 6) can be enhanced. As a result, it is possible to suppress interfacial peeling and falling off of the convex pattern layer 2 and to ensure high adhesion. Further, (c) since the conductive particle distribution on the transparent substrate 1 side of the convex pattern layer 2 is sparse, it is possible to reduce the influence (reflection of light) of the conductive particles 4 existing in such a region, When the surface side where the distribution of the conductive particles 4 is sparse is directed to the outside light side (observer side), whitening of the image and a decrease in contrast due to the outside light can be prevented. On the other hand, when the surface of the conductive particle 4 having a sparse distribution is directed to the image display device side, whitening of the image and a decrease in contrast due to reflection of image light on the screen can be prevented. Further, (d) the structure in which the conductive particles exist as the lump portion 3 in the vicinity of the top of the convex pattern layer 2 has the effect of reducing the contact resistance when the convex pattern layer 2 is brought into contact with the grounding component, for example. There is also.

(Contact form or joining form of conductive particles)
Next, the contact form or joining form of the conductive particles 4 will be described in detail. The form shown in FIG. 7A is a form of contact between conductive particles, and this form is a form in which contact portions 18 between adjacent conductive particles 4 and 4 are substantially in point contact. Here, the point contact substantially refers to a projection in the observer direction of a portion where both particles 4 and 4 in the contact portion 18 appear to be continuously connected and integrated when observed with an optical microscope or an electron microscope. It means a contact whose length is less than 0.1 μm. This form is a contact form between the conductive particles constituting the lump portion 3 when the electrical resistance reduction process described later is not performed. Even in this contact form, the surface resistivity can be in the range of 0.5 to 10Ω / □.

  The form shown in FIG. 7B is a joining form between conductive particles. In this form, the contact portion 18 is in contact with the substantially upper surface. Here, the substantially upper surface contact is the projection length in the observer direction of the portion where both particles 4, 4 in the contact portion 18 appear to be continuously connected and integrated when observed with an optical microscope or an electron microscope. Means contact with a thickness of 0.1 μm or more. In this form, as will be described in detail in the electrical resistance reduction process described later, water or acid or both are brought into contact with the convex pattern layer 2 at the same time as or after the curing process of the convex pattern layer 2. This can be realized by a process for reducing the surface resistivity. As a result, the convex pattern layer 2 can be left in a high-temperature and high-humidity environment, washed with warm water, acid-treated, and the like, so that it does not use a high-cost copper plating process and is not treated. There is an effect that the surface resistance value, which was 10Ω / □, can be reduced to 0.1-5Ω / □ or less. For this reason, a bond due to the substantially upper surface contact is formed between the adjacent conductive particles 4 and 4 as shown in FIG. 7B despite no firing, and substrate damage and conductivity that occur during firing are formed. There is an advantage that there is no fear of peeling off due to a decrease in adhesion of the composition.

  The form shown in FIG. 7C is a form in which the metal component once dissolved from the particles is solidified again in such a form that it envelops between adjacent particle surfaces or fills gaps between the particles. The dissolution of the metal component from the particles is considered to be caused by the treatment of the conductive particles 4 constituting the convex pattern layer 2 with an acid, but the principle is unclear.

  In any case, by performing the electrical resistance reduction process, the electrical resistance of the convex pattern layer 2 can be reduced to about 1/5 to 1/2 as compared with the unprocessed case shown in FIG. Can do.

  Here, reference is made to the volume resistivity of the pattern made of the conductive composition. The apparent value of the volume resistivity of the pattern made of the conductive composition varies depending on the pattern to be formed. For example, compared to the volume resistivity when a commercially available conductive paste is formed in a solid shape (a shape without an opening), the apparent volume resistivity when formed with the pattern of the following formula is a fine pattern shape to be formed The bigger it is. “Apparent volume resistivity [Ω · cm] = pattern portion surface resistivity [Ω / □] × pattern portion thickness [cm] × pattern occupancy ratio (Formula 1)”. Here, the pattern portion thickness is “(thickness of the pattern forming portion) − (total thickness of the non-pattern forming portion (opening))”, and the pattern occupancy is the pattern formation in the unit area. It is the ratio of the area of the part.

For example, the volume resistivity when a commercially available dry-curing silver paste is solidly applied and dried is usually 10 ⁻⁵ [Ω · cm] or less, but when the mesh pattern is actually printed, the apparent volume resistivity is Often more than an order of magnitude higher. This is due to a reduction in the filling rate of silver particles and the chance of contact between the particles. For example, even when the pattern occupancy is the same, the resistance increases as the line width and thickness become closer to the particle size of the conductive particles. Here, if the electrical resistance reduction process described above is applied, an increase in volume resistivity can be suppressed. In particular, by performing the electrical resistance reduction process using temperature and humidity, the apparent volume resistivity can be reduced to a value of 80 to 50% compared to before performing the process. Further, even by acid treatment, the apparent volume resistivity can be reduced to a value of 80 to 50% compared to before the treatment.

(Primer layer)
Although the primer layer 6 is an arbitrary layer, it is a layer preferably provided on the transparent substrate 1 in the present invention. The main purpose of providing the primer layer 6 is to improve the transferability of the conductive composition 2 'from the intaglio 40 to the transparent substrate 1 when the convex pattern layer 2 is formed by intaglio printing, as shown in FIG. This is for improving the adhesion between the conductive composition 2 ′ after the transfer and the transparent substrate 1. That is, both the transparent substrate 1 and the convex pattern layer 2 have good adhesion, and in order to ensure good light transmission at the opening (the convex pattern layer non-formation part B, see FIG. 3). It is also a transparent layer. Further, the primer layer 6 is provided on the transparent substrate 1 in a state where fluidity can be maintained, and is formed as a layer that is cured while in contact with the intaglio 40 during intaglio printing.

  The material constituting the primer layer 6 may be a thermoplastic resin composition or an ionizing radiation curable resin composition. Examples of the thermoplastic resin include acrylic resins such as polymethyl methacrylate (PMMA), vinyl chloride-vinyl acetate copolymers, polyester resins, and polyolefin resins.

  Further, as the ionizing radiation curable resin, a monomer (monomer) that is polymerized and cured by a reaction such as crosslinking with ionizing radiation, or a prepolymer or an oligomer is used. As a monomer, for example, as a radical polymerizable monomer, for example, 2-ethylhexyl (meth) acrylate, diethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, Examples include various (meth) acrylates such as pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meth) acrylate. Alternatively, examples of the cationic polymerizable monomer include alicyclic epoxides such as 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate, and glycidyl ethers such as bisphenol A diglycidyl ether, 4 -Vinyl ethers such as hydroxybutyl vinyl ether, oxetanes such as 3-ethyl-3-hydroxymethyl oxetane, and the like. Examples of the prepolymer (or oligomer) include radically polymerizable prepolymers, specifically, urethane (meth) acrylate, epoxy (meth) acrylate, polyester (meth) acrylate, triazine (meth) acrylate, and the like. (Meth) acrylate prepolymers, polythiol prepolymers such as trimethylolpropane trithioglycolate, pentaerythritol tetrathioglycolate, and unsaturated polyester prepolymers. Other examples include cationically polymerizable prepolymers such as novolac epoxy resin prepolymers and aromatic vinyl ether resin prepolymers. Here, the notation (meth) acrylate means acrylate or methacrylate. 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.

  As the photopolymerization initiator, in the case of a radically polymerizable monomer or prepolymer, a benzophenone-based, acetophenone-based, thioxanthone-based, benzoin-based compound, etc., or in the case of a cationic polymerization-based monomer or prepolymer, , Metallocene-based, aromatic sulfonium-based and aromatic iodonium-based compounds are used. These photopolymerization initiators are added in an amount of about 0.1 to 5 parts by weight with respect to 100 parts by weight of the composition comprising the monomer and / or prepolymer. The ionizing radiation is typically ultraviolet rays or electron beams, but other than these, electromagnetic waves such as visible rays, X-rays and γ rays, or charged particle beams such as α rays can also be used.

  Additives are added as necessary. Examples of the additive include a heat stabilizer, a radical scavenger, a plasticizer, a surfactant, an antistatic agent, an antioxidant, an ultraviolet absorber, an infrared absorber, a dye (colored dye, colored pigment), and an extender pigment. , Light diffusing agents, solvents and the like.

  In addition, about a solvent, when the fluidity | liquidity of the composition for primer layers itself is inadequate, it adds as needed. The solvent is used to increase the fluidity when the primer layer 6 is formed on the transparent substrate 1, to make the coating film thickness uniform, and to improve the mirror smoothness of the coating film surface.

  When the primer layer 6 is peeled after being cured on the plate surface, when using a material system that is heavyly peeled (adhesion with the plate is good), a release process is performed on the plate surface or a release material is applied. However, in consideration of the processing cost and the life of the releasing ability, a releasing agent is added to the primer layer 6 as necessary. The mold release agent means that the primer layer 6 on the transparent substrate 1 that has undergone the primer curing step in the production of the electromagnetic wave shielding material has a small force (peeling force) required for peeling from the plate surface and can be peeled off smoothly. An additive for improving peelability.

  Examples of the release agent include higher fatty acid esters, phosphate esters, silicone resin release agents, fluororesin release agents, and the like of mono- or polyhydric alcohols. The higher fatty acid ester is preferably a partial ester or complete ester of a monovalent or polyhydric alcohol having 1 to 20 carbon atoms and a saturated fatty acid having 10 to 30 carbon atoms. Examples of partial esters or complete esters of mono- or polyhydric alcohols and saturated fatty acids include stearic acid monoglyceride, stearic acid monosorbate, behenic acid monoglyceride, pentaerythritol monostearate, pentaerythritol tetrastearate, propylene glycol monostearate , Stearyl stearate, palmityl palmitate, butyl stearate, methyl laurate, isopropyl palmitate, 2-ethylhexyl stearate and the like. Among these, stearic acid esters such as stearic acid monoglyceride and pentaerythritol tetrastearate are particularly preferable from the viewpoints of transparency and releasability. These release agents can be used alone or in combination of two or more. The release agent is preferably added in an amount of 0.1 to 5 mass%, particularly preferably 0.5 to 3 mass%, based on the total amount of the ionizing radiation curable composition forming the primer layer 6. If it is less than 0.1% by mass, the releasability from the plate surface of the primer layer 6 is not improved, and even if it is added in excess of 5% by mass, the release performance is saturated and it is not economical.

  The ionizing radiation curable composition may contain a solvent, but in that case, a drying step is required after coating. Therefore, in view of cost, a non-solvent type (solvent-free type) that does not contain a solvent is preferable. When a solvent is added for the purpose of improving the appearance or coating suitability, drying is required. However, if the amount of the solvent is about several percent, it may be dried after curing. The amount of residual solvent is preferably as small as possible, but may not be completely zero as long as there is no influence on physical properties and durability.

  However, as shown in FIG. 9, when the primer layer 6 is pressure-bonded onto the intaglio plate 40 filled with the conductive composition 2 ′ in the recess 34, the solvent in the primer layer 6 has no practical problem. It is preferable to dry and remove to a sufficient extent. Further, in the primer layer 6 sandwiched between the intaglio 40 and the transparent substrate 1, the residual solvent in the primer layer 6 is vaporized without escape, and bubbles may be generated in the cured primer layer. It is also because there is. In addition, what is necessary is just to select suitably the solvent used here from the thing similar to what is listed as a solvent of the composition for transparent protective layer formation mentioned above.

  The primer layer 6 can maintain two states, a fluidized state and a cured (or solidified) state, in a state where it is pressure-bonded to the plate. Specifically, the primer layer 6 is provided on the transparent substrate 1 in such a state that the fluidity can be maintained after the primer layer resin composition is applied, and then the conductive property is applied on the primer layer 6. When the composition layer 2 ′ (see FIG. 9) is transferred and formed, it can be changed from a fluidized state to a cured state in a short time. By forming the primer layer 6 on the transparent substrate 1, when transferring the conductive composition layer 2 ′ onto the primer layer 6, there is a gap between the conductive composition layer 2 ′ and the primer layer 6. Therefore, the gap between the conductive composition layer 2 ′ and the primer layer 6, which may have occurred in the past, can be eliminated, and transfer defects and adhesion due to the existence of the gap can be eliminated. There is no defect problem.

  In addition, the “fluidity” or “fluid state” of the primer layer 6 referred to in the present application means a property or state of fluidizing (deforming) by pressure when the primer layer 6 is pressure-bonded to a plate surface filled with the conductive composition. Good, it doesn't have to be as low as water. Further, it is not always necessary to have Newtonian viscosity, and it may have non-Newtonian viscosity such as thixotropic property or dilatancy property. After the primer layer adjusted to a viscosity suitable for coating is applied on the transparent substrate 1, when the primer layer 6 is a thermoplastic resin, it may flow (deform) when it is pressure-bonded to the plate surface. The primer layer 6 only needs to have a temperature that flows (deforms) during pressure bonding. In this case, it may be paraphrased as a softened state. The viscosity of the primer layer 6 in a fluid state is usually in the range of 1 mPa · s to 100,000 mPa · s, and preferably in the range of 50 mPa · s to 2000 mPa · s.

  The fluidity state of the primer layer 6 is such that when ionizing radiation curable resin that is liquid at room temperature in the uncured state is used as the primer layer resin, ink having ionizing radiation curable properties is applied onto the transparent substrate 1. It can be obtained simply by applying. The ionizing radiation curable ink is generally composed of a monomer or oligomer having ionizing radiation curable properties as described above, and further, if necessary, a photopolymerization initiator (in the case of ultraviolet curing or photocuring), various additives, and the like. It exhibits fluidity until cured with ionizing radiation. This ink may contain a solvent, but in this case, since a drying step is required after coating, the ink is preferably of a type that does not contain a solvent (so-called non-solvent type).

  In addition, when a thermoplastic resin composition that is solid at room temperature is used as the primer layer resin, the thermoplastic resin composition is applied on the transparent substrate 1 and becomes fluid (eg, 50 ° C.). To about 200 ° C.). If the primer layer 6 in a fluid state is pressure-bonded to a plate surface filled with a conductive composition as will be described later, and then cured and transferred by cooling, the conductive composition layer 2 ′ and the primer layer 6 are transferred. The transfer can be performed in a state where there is no gap between the two. Here, as a method of applying the thermoplastic resin composition on the transparent substrate 1, there are a method of applying a solution of the thermoplastic resin composition and then drying, and a method of applying a resin in a hot melt state. The thermoplastic resin composition applied on the transparent substrate 1 may be heated before contacting the plate surface filled with the conductive composition, and a heating roll or the like is used when pressure-bonding to the plate surface. However, in any case, when the conductive composition layer 2 ′ is transferred to the primer layer 6, the primer layer needs to be cooled to such an extent that the fluidity of the primer layer is lost.

It is not particularly limited and the thickness of the primer layer 6 is usually formed so as to 1μm~100μm about a thickness after curing (numbers were evaluated by the later thickness T _B). Moreover, the thickness (T _B ) of the primer layer 6 is usually the total value of the convex pattern layer 2 and the primer layer 6 (total thickness. In FIG. 3, the top of the convex pattern layer 2 and the transparent substrate 1 to 50%, and preferably 1 to 30%. In addition, although it explains in full detail in the description column of a later manufacturing method, electroconductive composition layer 2 'was transcribe | transferred on the primer layer 6, and also the electroconductive composition layer 2' was hardened, and the electromagnetic wave shielding material was manufactured. As shown in FIG. 3 and the like, the primer layer 6 at a later stage has a thickness TA of a portion _A where the convex pattern layer 2 is formed, and a thickness T of a portion B where the convex pattern layer 2 is not formed. Thicker than _B. In the primer layer 6, the side edges 7 and 7 of the thick part A are in a form in which the convex pattern layer 2 wraps around the thin part B as shown in FIG. 3. ing.

  In the embodiment shown in FIG. 3 and the like, the primer layer 6 in a fluid state before being cured is pressure-bonded to the conductive composition provided in the intaglio, and then the primer layer 6 is cured, and the primer layer 6 and the conductive composition are cured. The primer plate 6 having a predetermined pattern filled with an object is pressure-bonded, and the primer layer 6 and the conductive composition are closely contacted without gaps (if there is a dent 17 shown in FIG. 9, this is filled), then the primer It can be formed by curing the layer 6 or by simultaneously curing the primer layer 6 and the conductive composition and then transferring them. As an example, as shown in the manufacturing process diagrams of FIGS. 9A, 9C, and 9D described later, the primer layer 6 formed on the transparent substrate 1 is made into a fluid state, and the primer layer 6 is made of a conductive composition. It can be formed by press-bonding the product 2 ′ to the printing plate filled in the recesses and curing the primer layer 6. On the plate surface, excess conductive composition other than the inside of the recess is scraped off by a doctor blade, a wiping roll, or the like. At that time, the upper portion of the conductive composition in the recess is caused by volatilization of the solvent or the like in FIG. As shown in FIGS. 9 (A) and 9 (B), the primer layer 6 having fluidity is dented by pressing the primer layer 6 on the plate surface with the dent 17 easily formed. 17 flows in and is filled, resulting in the form shown in FIG.

  When the convex pattern layer 2 formed in this way has a mesh shape, the line portions formed of two or more parallel line groups having different directions intersect with each other, and are surrounded by these line portions to form openings ( A pattern non-forming part B) is formed. In addition, even when three or more groups of parallel lines (line portions) intersect, the basic design points and operational effects are the same. 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 °, but those with θ = 90 ° are usually widely used. It has been.

(Cross sectional form of convex pattern layer and primer layer)
As shown in FIGS. 8A to 8C, the interface between the convex pattern layer 2 made of the conductive composition and the primer layer 6 can take three cross-sectional forms. Specifically, as shown in FIG. 8A, a first cross-sectional form in which the interface between the primer layer 6 and the convex pattern layer 2 is non-linearly interlaced, as shown in FIG. 8B. As shown in FIG. 8C, the second cross-sectional form having a layer in which the component constituting the primer layer 6 and the component constituting the convex pattern layer 2 are mixed, and the convex pattern layer 2 The 3rd cross-sectional form in which the component contained in the primer layer 6 exists in the electrically conductive composition which comprises can be mentioned. These cross-sectional forms (also referred to as interface forms) give favorable results in terms of adhesion and transferability of the conductive composition.

  As shown in FIG. 8A, the first cross-sectional form is such that the interface 13 between the primer layer 6 and the convex pattern layer 2 is alternately non-linear on the primer layer 6 side and the convex pattern layer 2 side. It is a complicated form. In the first cross-sectional form, the intricate interface has a mountain-shaped cross-sectional form with a high center as a whole. In this embodiment, the interface 13 may be configured to be an interface between the resin constituting the primer layer 6 and the binder resin 5 or the conductive particles 4 constituting the convex pattern layer 2. The conductive pattern 4 in the convex pattern layer 2 and the resin constituting the primer layer 6 are formed in a non-linear manner. At this time, the degree and form of intricateness are affected by the shape and size of the conductive particles 4, the pressure when the primer layer 6 is pressure-bonded in the recess, and the like. Since the vicinity of this interface is a sparse region R shown in FIGS. 5F and 5G, the proportion of the conductive particles 4 in contact with each other in the binder resin 5 is low and floats in the binder resin. Present in a state that exists in the state.

  In the first cross-sectional form, in addition to the fact that the convex pattern layer 2 is formed on the mountain-shaped primer layer 6 which is not a flat surface in the first place, the adhesion is good, and the interface as described above. Since the conductive particles 4 are present in a floating state in the binder resin, the adhesion between the primer layer 6 and the convex pattern layer 2 is extremely high due to the so-called anchoring effect. It is high. Furthermore, since it takes such a cross-sectional form, it has a special effect that the conductive composition filled in the plate recess is transferred onto the primer layer 6 with an extremely high transfer rate (approximately 100%).

  As shown in FIG. 8 (B), the second cross-sectional form includes a primer component contained in the primer layer 6 and the convex pattern layer 2 in the vicinity of the interface 13 between the primer layer 6 and the convex pattern layer 2. This is a form in which a mixing region 14 in which constituent components are mixed is present. Although the interface appears clearly in FIG. 8B, in reality, an unclear and ambiguous interface appears. In FIG. 8B, the mixed region 14 exists so as to sandwich the interface 13 vertically. In this case, the primer component in the primer layer 6 and the arbitrary component in the convex pattern layer 2 penetrate into each other. In addition, the mixing area | region 14 may exist in the upper side (opposite side to the transparent base material 1) of the interface 13, or may exist in the lower side (transparent base material 1 side). As the case where the mixed region 14 exists above the interface 13, the primer component in the primer layer 6 penetrates into the convex pattern layer 2 and the component in the convex pattern layer 2 does not penetrate into the primer layer 6. On the other hand, when the mixed region 14 exists below the interface 13, any component in the convex pattern layer 2 penetrates into the primer layer 6, and the primer component in the primer layer 6 is convex. This is a case where the pattern layer 2 does not enter.

  In the second cross-sectional form, in addition to the fact that the convex pattern layer 2 is formed on the mountain-shaped primer layer 6 which is not a flat surface in the first place, in addition to the good adhesion, the interface as described above Since the mixed region 14 is provided in the vicinity of 13, the adhesion between the primer layer 6 and the convex pattern layer 2 is remarkably increased. Furthermore, since it takes such a cross-sectional form, it has a special effect that the conductive composition filled in the plate recess is transferred onto the primer layer 6 with an extremely high transfer rate (approximately 100%).

  As shown in FIG. 8C, the third cross-sectional form is a form in which the primer component 16 included in the primer layer 6 exists widely in the convex pattern layer 2. Although FIG. 8C schematically shows a mode in which the primer component 16 is large near the interface 13 and decreases toward the top, such a mode is not particularly limited. The primer component 16 may penetrate into the convex pattern layer 2 to the extent that it is detected from the top of the convex pattern layer 2, or may be an extent that is mainly detected in the vicinity of the interface. In this third cross-sectional form, in particular, when the region where the primer component 16 exists in the convex pattern layer 2 is localized in the vicinity of the interface 13, the mixed region is It can be said that it corresponds to a form existing only on the upper side of the interface 13.

  Even in the case of the third cross-sectional shape, as in the case of the first and second cross-sectional shapes, the convex pattern layer 2 is formed on the mountain-shaped primer layer 6 that is not a flat surface. In addition to good adhesion, since the primer component 16 penetrates into the convex pattern layer 2 as described above, the adhesion between the primer layer 6 and the convex pattern layer 2 is remarkably increased. Furthermore, since it takes such a cross-sectional form, it has a special effect that the conductive composition filled in the plate recess is transferred onto the primer layer 6 with an extremely high transfer rate (approximately 100%).

  The interface 13 between the convex pattern layer 2 and the primer layer 6 made of the conductive composition in the present invention has at least one of the above-mentioned first to third cross-sectional features. You may have one or more, and you may have all three.

(Metal layer)
The metal layer 8 is formed as necessary in order to further improve the electrical conductivity when the desired electrical conductivity is insufficient with only the convex pattern layer 2. It is formed on the convex pattern layer 2 by plating. Plating methods include electro (electrolytic) plating, electroless plating, etc. Electroplating can increase the plating rate several times by increasing the amount of current compared to electroless plating, and productivity Can be remarkably improved.

  In the case of electroplating, power feeding to the convex pattern layer 2 is performed from an electrode such as an energizing roll brought into contact with the surface on which the convex pattern layer 2 is formed, but the convex pattern layer 2 can be electroplated. Since it has conductivity (for example, 10Ω / □ or less), electroplating can be performed without any problem. Examples of the material constituting the metal layer 8 include copper, silver, gold, chromium, nickel, and tin, which are highly conductive and can be easily plated. Since the metal layer 8 generally has a volume resistivity smaller by one digit or more than the convex pattern layer 2, the amount of the conductive material required is smaller than when the convex pattern layer 2 alone secures electromagnetic wave shielding. There is an advantage that it can be reduced.

  Note that after the metal layer 8 is formed, the metal layer 8 may be blackened or the surface may be roughened as necessary. Examples of the blackening treatment include blackening nickel plating and copper-cobalt alloy plating, but are not necessarily limited thereto.

(Transparent protective layer)
The transparent protective layer (not shown) is formed on the entire surface covering the convex pattern layer 2 (including the convex pattern layer 2 on which the metal layer 8 is formed). The material for forming the transparent protective layer is not particularly limited, and ionizing radiation curable resins conventionally used as the transparent protective layer of the electromagnetic wave shielding material are preferably used. The thickness of the transparent protective layer is also not particularly limited, and is usually preferably thicker than the height H of the convex pattern layer 2.

  As described above, according to the present invention, the conductive composition including the conductive particles 4 and the binder resin 5 having an average particle diameter of 1/4 or less the line width W of the convex pattern layer 2. However, since the 16 or more conductive particles 4 have the lump part 3 in contact with each other on the transverse cut surface of the raised pattern layer 2, the lump part 3 can realize the low resistance raised pattern layer 2 and electromagnetic waves. Shield characteristics can be improved. As a result, the wiring width of the convex pattern layer 2 can be further reduced.

[Method of manufacturing electromagnetic shielding material]
Next, a method for manufacturing the electromagnetic wave shielding material 10 will be described with reference to FIGS. In the present application, “transfer” and “transfer” are used synonymously. Therefore, “transfer” can be replaced with “transfer”, and “transfer process” can be replaced with “transfer process”.

  As shown in FIG. 9, the method of manufacturing the electromagnetic shielding material 10 includes a plate surface 33 having a predetermined pattern of recesses 34 filled with an uncured conductive composition 2 ′, and a transfer target of the conductive composition 2 ′. Is bonded to one surface S1 of the transparent base material 1 through a primer layer 6 that can maintain fluidity until it is cured, and then at least the primer layer 6 is cured in a state in which the pressure bonding is retained, The transparent substrate 1 and the primer layer 6 are peeled off from the plate surface 33, and the conductive composition 2 ′ is transferred to the one surface S1 of the transparent substrate 1 through the primer layer 6 in a predetermined pattern. Is.

  Specifically, FIG. 9A shows the side on which the primer layer 6 that can maintain fluidity until it hardens on the plate surface 33 of the intaglio plate 40 filled with the uncured conductive composition 2 ′ in the recess 34. This is a step for pressure bonding the transparent substrate 1. That is, in this step, first, a primer layer 6 in a fluid state is applied in advance on the surface S1 of the transparent substrate 1, while a concave portion having a predetermined pattern filled with an uncured conductive composition 2 ′. Primer capable of maintaining fluidity until the plate surface 33 and one surface S1 of the transparent substrate 1 to which the conductive composition 2 ′ is to be transferred are cured. The process of trying to press-fit through the layer 6 is shown.

  The primer layer 6 can be formed on the plate surface 33 side. That is, as shown in FIG. 9B and FIG. 11, the primer layer that can maintain fluidity until it is cured so as to cover the entire plate surface 33 including the concave portion 34 filled with the uncured conductive composition 2 ′. 6 is provided by coating, and the surface S1 side of the uncoated transparent base material 1 is pressure-bonded from above the primer layer 6. However, while it is relatively easy to apply the primer layer forming composition on the transparent substrate 1, it is relatively difficult to apply the primer layer forming composition on the plate surface 33. In particular, when the intaglio plate 40 has a cylindrical shape as shown in FIG. 11, the primer layer applied by gravity hangs down, making it difficult to apply a uniform film thickness. Therefore, in the present invention, it is preferable to adopt a form in which the primer layer 6 is applied to the transparent substrate 1 side as shown in FIGS. 9 (A) and 10.

9A and 9B, the conductive composition 2 ′ is not present at all or substantially not present on the plate surface other than the concave portion 34. Here, “substantially non-existent” means that the conductive composition 2 ′ is used by using a doctor blade (see reference numeral 35 in FIG. 11), a wiping roll (see reference numeral 44 in FIG. 10), or the like. When the conductive composition 2 ′ is also present in the plate surface 33 (surface) other than the concave portion 34 when filling the concave portion 34 with FIG. 9D (D) finally obtained. The electromagnetic wave shielding material 10 shown in FIG. 3) can allow the presence of the conductive composition 2 ′ in the convex pattern layer non-formed part B (the part where the convex pattern layer 2 is not formed) to such an extent that the purpose is not impaired. Means. As the acceptable degree, for example, as described above, 'the, thickness T _C convex pattern layer 2 made of conductive composition 2' conductive composition 2 coating on the convex pattern layer non-formation part B of And the characteristics such as the transmittance of the convex pattern layer non-forming part B, and the like. Such thickness T _C , coverage, characteristics, and the like vary depending on the specifications of the electromagnetic wave shielding material 10 that forms the convex pattern layer 2, but in any case, the conductive pattern is not included in the convex pattern layer non-forming part B. The conductive composition 2 'on the plate surface 33 is scraped off so that the product 2' is not present at all or substantially absent.

  FIG. 9C is a step of pressure bonding the transparent substrate 1 and the plate surface 33 through the primer layer 6 that can maintain fluidity until it is cured. After passing through the process route of FIG. 9A, when the conductive composition 2 ′ is scraped off from the plate surface 33 using a doctor blade, a wiping roll or the like, the “conductive composition 2 ′ ”Is formed in the recess 34, and the recess 17 is filled with the flowable primer layer 6 until it is cured at the time of crimping. In the process route of FIG. 9B, the primer layer 6 fills the recess 17 when the primer layer is provided on the plate surface 33. Therefore, in the step of FIG. 9C, the transparent base material 1 and the plate surface 33 are pressure-bonded in a mode through the primer layer 6, and as a result, the primer layer 6 that has fluidity until cured is a conductive composition. The 2 'dent 17 is filled. At this time, the conductive composition 2 ′ is also kept in an uncured state. As a result, structures as shown in FIGS. 8A to 8C are formed at the interface between the conductive composition layer and the primer layer. In the present invention, at least the primer layer 6 is cured in a state where the pressure bonding is maintained. “At least” means that only the primer layer 6 is cured and the conductive composition 2 ′ is not cured, and that the primer layer 6 and the conductive composition 2 ′ are simultaneously cured. . And it is preferable to perform the hardening process by ionizing radiation irradiation or cooling.

  FIG. 9D shows an embodiment in which the transparent substrate 1 and the primer layer 6 are peeled off from the plate surface 33 thereafter. In the obtained electromagnetic wave shielding material 10, the conductive composition 2 ′ was able to be transferred in a predetermined pattern onto one surface S 1 of the transparent substrate 1 through the primer layer 6. Here, FIGS. 9C and 9D show shapes close to actual cross-sectional observation results, but the shapes of the primer layer 6 and the convex pattern layer 2 shown in FIG. The reason that the shapes of the primer layer 6 and the conductive composition 2 ′ shown in C) do not completely match is that the constituent materials of both layers are resin materials having plasticity. In addition, the convex pattern layer 2 may be hardened in the step of FIG. 9C, or may be hardened after the peeling step of FIG. 9D.

  Next, the manufacturing method and manufacturing apparatus shown in FIGS. 10 and 11 will be described. In the method for manufacturing the electromagnetic shielding material 10 shown in FIG. 10, first, the primer layer 6 is applied to one surface of the supplied transparent substrate 1. This application step is performed by the pickup roll 41 coming into contact with the primer layer resin composition 42 in the container 43 at the lower side, pulling up the primer layer resin composition 42 and applying it to the transparent substrate 1. The transparent substrate 1 to which the primer layer 6 is applied is performed by pressing the substrate surface (S1) on the primer layer 6 side to the plate surface 33 by a nip roll 36. On the other hand, the conductive composition 2 ′ is applied to the plate surface 33 to be pressed. The application process at this time is performed by the pickup roll 31 coming into contact with the conductive composition 2 ′ in the container 38 at the lower side and pulling up the conductive composition 2 ′ and applying it to the plate surface 33. In FIG. 10, the wiping roll 44 scrapes off the conductive composition 2 ′ so that the conductive composition 2 ′ does not get on the portion other than the concave portion 34 on the plate surface 33.

  The pressure bonding is performed by energizing the base material surface on the primer layer 6 side to the plate surface 33 with a predetermined pressure by the nip roll 36 to bring it into close contact. By this pressure bonding, the conductive composition 2 ′ and the primer layer 6 in the recess 34 can be adhered to each other without a gap. Since the primer layer 6 is not cured yet and has fluidity, the resin composition for the primer layer is filled in the recess 17 shown in FIG. 9A, and the transparent substrate 1 and the conductive composition are filled. The space between the objects 2 'is filled with the primer layer 6 without any gaps.

  After the pressure bonding step with the nip roll 36 shown in FIG. 10, the primer layer 6 and the conductive composition 2 ′ are in close contact with each other without gaps, and then ultraviolet rays such as a high-pressure mercury lamp in the region marked “UV zone” in FIG. 10. A curing process is performed by irradiating ultraviolet rays radiated from a light source (not shown) to cure the primer layer 6, and then the transparent substrate 1 and the cured primer layer 6 are applied to the printing plate via a nip roll 37 (peeling roll). By passing through the transfer process of peeling from 33, the transfer (transfer) of the conductive composition 2 ′ filled in the plate surface to the transparent substrate 1 is reliably performed under a high transfer rate. And the convex pattern layer pattern which the obtained electromagnetic wave shielding material 10 has, as shown in FIG. 8, the interface 12 of the primer layer 6 and the convex pattern layer 2 does not have a simple interface structure, and both layers Improved adhesion. In addition, the cross section of the convex pattern layer 2 which consists of the thickness of the primer layer 6 and the predetermined pattern obtained, such as a drying process, a curing process, and a plating process, which are provided as necessary after that, a curing process and a transfer process Since the form, transition rate, aspect ratio, and the like are the same as those described in the description section of the electromagnetic wave shielding material 10 described above, description thereof is omitted here.

  On the other hand, instead of the embodiment shown in FIG. 10 employed in the present invention, a manufacturing method and a manufacturing apparatus in which the primer layer 6 is directly coated on the plate surface are also possible. The manufacturing method shown in FIG. 11 is different from the manufacturing method shown in FIG. That is, first, the transparent substrate 1 is supplied so as to be pressed against the plate surface 33 by the nip roll 36. As shown in FIG. 11, the conductive composition 2 ′ is first applied to the plate surface 33 to which the transparent substrate 1 is pressure-bonded, and then the primer layer 6 is formed by coating. The application process of the conductive composition 2 ′ is performed by the pickup roll 31 coming into contact with the conductive composition 2 ′ in the container 38 at the lower side and pulling up the conductive composition 2 ′ and applying it to the plate surface 33. Subsequently, the conductive composition 2 ′ is scraped off by a doctor blade 35 so that the conductive composition 2 ′ does not get on any portion other than the concave portion 34 on the plate surface 33. Similarly, in the application process of the primer layer 6, the pickup roll 41 contacts the primer layer resin composition 42 in the container 43 at the lower side, the primer layer resin composition 42 is pulled up, and the conductive material is formed in the recess 34. It is performed by applying a predetermined thickness on the plate surface 33 filled with the composition 2 ′. Since the primer layer resin composition is not yet cured and has fluidity, as shown in FIG. 9B, the recess 17 is filled with the primer layer resin composition without voids.

  The pressure bonding is performed by urging the transparent base material 1 to the plate surface 33 with a predetermined pressure by the nip roll 36 so as to be in close contact therewith. By this pressure bonding, the transparent substrate 1 is in close contact with the primer layer 6. Since the steps subsequent to the crimping step and other configurations such as the nip roll 36 are the same as those described with reference to FIG. 10, detailed description thereof will be omitted here, but after the crimping step with the nip roll 36 shown in FIG. 6 and the conductive composition 2 ′ are closely adhered to each other without a gap, and then the curing composition and the transfer process are performed to transfer (transfer) the conductive composition 2 ′ filled in the plate surface to the transparent substrate 1. Is reliably performed under high transition rates. And the convex pattern layer pattern which the obtained electromagnetic wave shielding material 10 has is the interface 12 between the primer layer 6 and the convex pattern layer 2 as shown in FIG. The interfacial structure is not improved and the adhesion between both layers is improved.

  In FIG. 10 and FIG. 11, a drum type plate is used, but it is not necessarily a drum type plate and may be a flat plate. When a lithographic plate is used, continuous production such as roll-to-roll as shown in FIG. 10 or FIG. 11 is not possible. However, a conductive composition 2 ′ is applied to a fixed lithographic plate, and then a doctor blade or the like is used. After scraping and then applying the primer layer resin composition 42 thereon, for example, the single-wafer transparent substrate 1 is pressure-bonded, or the single-wafer transparent substrate 1 provided with the primer layer 6 is pressure-bonded thereon. Then, the convex pattern layer 2 can be transferred to the substrate side by peeling off the transparent substrate 1 and the primer layer 6. And by repeating such a process, the sheet | seat electromagnetic wave shielding material 10 which has at least the primer layer 6 and the convex pattern layer 2 on the transparent base material 1 can be manufactured continuously.

  In particular, the characteristic mass portion 3 of the present invention contains the conductive particles 4 in the range of 90 to 99 parts by mass, preferably 92 to 98 parts by mass, out of 100 parts by mass of the solid content of the conductive composition. The conductive composition can be used and can be formed by the manufacturing method described above. That is, when such a conductive composition 2 ′ is filled in the concave portion 34 of the plate surface 33 and then transferred onto the primer layer 6, the lump portion 3 is provided near the top of the convex pattern layer 2. The reason why the lump 3 is present on the top side of the convex pattern layer 2 is considered to be that the primer layer 6 pushes the uncured conductive composition toward the top and the primer is cured in this state. In this way, 16 or more conductive particles 4 are in contact with each other, and a lump portion 3 is preferably formed on the top side of the convex pattern layer 2.

(Electrical resistance reduction process)
Here, the process of reducing the electrical resistance of the convex pattern layer 2 will be described in detail. In order to obtain the electromagnetic wave shielding material 10 according to the present invention, it is preferable to perform a process of reducing the electrical resistance of the convex pattern layer 2. For example, the surface resistivity reduction process which performs the process which reduces the surface resistivity by making the convex pattern layer 2 contact water or an acid or both simultaneously with the hardening process of the convex pattern layer 2, or after the hardening process. It is preferable to add a process. By this treatment, the volume resistivity of the convex pattern layer 2 can be reduced, and as a result, high conductivity is imparted to the lump 3 of the convex pattern layer 2, and high electromagnetic shielding characteristics can be imparted. Patent Document 5 proposes a method for manufacturing a conductive substrate in which a metal fine particle layer is treated with an acid in the production of a conductive substrate in which a metal fine particle layer is laminated on at least one surface of a substrate.

  The treatment for reducing the surface resistivity of the convex pattern layer 2 by bringing it into contact with water is as follows: (1) At the same time as or after the curing step of the convex pattern layer 2, the temperature is 50 to 90 ° C. and the relative humidity is 50 to 50. The process of exposing the convex pattern layer 2 over a predetermined time in a high-temperature and high-humidity environment of 95%, or (2) after the step of curing the convex pattern layer 2, the convex pattern layer in hot water at a predetermined temperature 2 is a treatment of immersing 2 for a predetermined time. On the other hand, the process of reducing the electrical resistance of the convex pattern layer 2 by contacting with acid is a process of immersing the convex pattern layer 2 after the curing process in an acid solution, or the convex pattern layer 2 after the curing process. A process of applying an acid solution to the substrate.

  These treatments are observed particularly when the conductive particles 4 are silver particles or particles containing silver. Unlike so-called baking treatment, this treatment is not a long-time heat treatment that damages a general film substrate such as PET, but also a dispersion of nanometer-size particles known as printing ink for low-temperature baking. Cannot be used. However, it is preferable for the conductive composition comprising the conductive particles 4 having a mean particle diameter of 1 μm or more and 1/4 of the line width of the convex pattern layer and the binder resin 5 used in the present invention. It is a means that can be applied.

  More specifically, in the former process of bringing the water into contact with each other and reducing the electrical resistance, the electromagnetic wave shielding material 10 was brought into contact with moisture after the convex pattern layer 2 was transferred to the transparent substrate side and cured. In this state, the substrate is left at a temperature higher than room temperature (about 25 ° C.) for an appropriate time. As the conditions in the presence of moisture, any of standing in air containing water vapor, spraying of water droplets, or immersion in water may be used. In the case of leaving in air containing water vapor, the relative humidity of the air to be left is 70% RH or more, preferably 85% RH or more. The temperature (atmospheric temperature when left in air containing water vapor or water droplets, and water temperature when immersed in water) is 30 ° C. or higher, preferably 60 ° C. or higher. However, if the temperature is too high, the binder resin 5 and the transparent base material 1 may be altered or changed. The treatment time is preferably set after testing in advance a time that becomes constant after the surface resistance is lowered, but it is preferable to set the time to about 48 hours since it becomes substantially constant after 48 hours even if there is a margin.

  By the electrical resistance reduction process by contact with warm water, the surface resistivity of the entire convex pattern layer can be reduced to about 20 to 50% before the process. The apparent volume resistivity is also about 20 to 50% before processing. Particularly used in the present invention, a conductive composition comprising conductive particles 4 (particularly silver particles) having an average particle diameter of 1 μm or more and not more than 1/4 of the line width of the convex pattern layer, and a binder resin 5. About a thing (silver paste), the surface resistivity after a process can be made small. Also, when the metal layer 8 is formed by electrolytic plating, the plating process speed can be increased and the productivity can be improved by reducing the surface resistance value by this process.

  The reason why the volume resistivity is decreased by the treatment is not yet elucidated at the present time. For example, when silver particles are used as the conductive particles 4 and the state change of the silver particles before and after the treatment is observed with a SEM (scanning electron microscope), Changes in the shape of 16 or more silver particles constituting the mass 3, fusion between adjacent particles, a decrease in the distance between the particles, etc. are observed, and the conductive particles shown in FIG. From the form in which the point is substantially in contact (reference numeral 18 is a contact part), as shown in FIG. 7B, adjacent silver particles are fused (reference numeral 19 is a joint part), and the mass part 3 is in a state of substantially contacting the upper surface. It is presumed that the volume resistivity is reduced and this is the direct cause.

  On the other hand, the process of reducing the electrical resistance by bringing the latter acid into contact is performed by transferring the convex pattern layer 2 to the transparent substrate side and then bringing the electromagnetic wave shielding material into contact with an acid so that the volume resistance of the convex pattern layer 2 This is a process for reducing the rate. The acid is not particularly limited, and can be selected from various inorganic acids and organic acids. Examples of the inorganic acid include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid and the like. Examples of the organic acid include acetic acid, citric acid, succinic acid, propionic acid, lactic acid, and benzenesulfonic acid. These may be strong acids or weak acids. Acetic acid, hydrochloric acid, sulfuric acid, and an aqueous solution thereof are preferable, and hydrochloric acid, sulfuric acid, and an aqueous solution thereof are more preferable. The contact time with the acid is sufficient to be several minutes or less, and even if the time is increased, the effect of improving the conductivity is not increased, and the effect of improving the conductivity may be deteriorated. The contact time with the acid is preferably 15 seconds to 60 minutes, more preferably 15 seconds to 30 minutes, still more preferably 15 seconds to 2 minutes, and particularly preferably 15 seconds to 1 minute. . The temperature of the acid to be contacted is sufficient at room temperature. When the treatment is performed at a high temperature, acid vapor is generated and the surrounding metal device is corroded and deteriorated, or when a thermoplastic resin film is used as the transparent substrate, the transparent substrate is whitened. Since transparency may be impaired, it is not preferable. A preferable treatment temperature is 40 ° C. or lower, more preferably 30 ° C. or lower, and further preferably 25 ° C. or lower.

  The method of contacting with an acid is not particularly limited. For example, the convex pattern layer 2 is immersed in an acid or an aqueous solution of an acid, an acid or an aqueous solution of an acid is applied on the convex pattern layer 2, or an acid solution is used. A method of spraying droplets or applying a vapor of an acid or an aqueous solution of an acid to the convex pattern layer 2 is used. Among these, the method of immersing the convex pattern layer 2 in an aqueous solution of acid or applying an acid or an aqueous solution of an acid on the convex pattern layer 2 is preferable because of its excellent conductivity improving effect. That is, as the conditions for the contact treatment with the acid, the convex pattern layer 2 is immersed in an aqueous acid solution at a temperature of 40 ° C. or less, or an acid or an aqueous acid solution is applied on the convex pattern layer 2. It is preferable.

  When an acid aqueous solution is used, the acid concentration is preferably 10 mol / L or less, more preferably 5 mol / L or less, and further preferably 1 mol / L or less. If the concentration of the aqueous acid solution is high, workability may decrease and productivity may deteriorate, or if a thermoplastic resin film is used as the transparent substrate, the transparent substrate will be whitened to improve transparency. Since it may be damaged, it is not preferable. In addition, even when the acid concentration is too low, the effect of the treatment with the acid cannot be obtained, so that it is preferably 0.05 mol / L or more, more preferably 0.1 mol / L or more. In addition, when using the aqueous solution of an acid, since the bad influence by an acid residue may be anxious, the process of rinsing with water and a drying process is needed after a process. When hot water or steam is used, the rinsing step can be omitted.

  In addition, the contact treatment with water or the contact treatment with acid as the electric resistance reduction step may be performed by selecting either one of them individually, but both treatments are sequentially performed (merged or combined). May be. In this case, in particular, it is preferable to perform the contact treatment with acid first and then perform the contact treatment with hot water because the effect of reducing electric resistance is great.

  Thus, by performing the contact treatment with water (high-temperature wet heat treatment) or the contact treatment with acid at the same time or after the curing of the convex pattern layer 2, the fusion between the conductive particles occurs, and the volume resistance As for whether the rate decreases, (a) promotion of metal diffusion between silver particles by washing the particle surface (see FIG. 7B), (b) shrinkage of binder resin by moisture or acid, (c) ) Reduction of solvent component, (d) Solidification again in such a form that the metal component once dissolved from the particles envelops the surfaces of adjacent particles or fills the gaps between the particles (reference numeral 4 ′). (See FIG. 7C), etc., can be considered, but the true reason has not been confirmed yet. In addition, it has been confirmed that the volume resistivity is not reduced by simply performing a heat treatment at 80 ° C., and it is also confirmed that the rate of decrease in the resistivity is small unless sufficient drying is performed after the acid treatment. However, the electrical resistance of the convex pattern layer 2 can be reduced to about 1/5 to 1/2 by the electrical resistance reduction process.

  As described above, according to the method for producing the electromagnetic shielding material 10 according to the present invention, the conductive particles 4 are 90 to 99 parts by mass, preferably 92 to 98 parts, out of 100 parts by mass of the solid content of the conductive composition. A plate surface 33 having a concave portion 34 of a predetermined pattern filled with an uncured conductive composition 2 ′ contained within the range of mass parts, and a transparent substrate 1 that is a transfer target of the conductive composition 2 ′. Since one surface S1 is pressure-bonded via a primer layer 6 that can maintain fluidity until it is cured, the primer layer 6 having fluidity is formed in the recess 17 that is likely to be formed on the conductive composition 2 'in the recess 34. Filled. As a result, the primer layer 6 is in close contact with the recess 17 of the conductive composition 2 ′ without gaps, so that the conductive composition 2 ′ in the recess 34 is accurately transferred without any untransferred portion on the transparent substrate 1 side. Can be made. In addition, on the top side of the formed convex pattern layer 2, there is a lump portion 3 of conductive particles 4 having a specific particle aggregation form, and the extension direction of the convex pattern layer 2 by the lump portion 3. Therefore, the convex pattern layer 2 which is stable and has a low surface resistivity can be formed. As a result, sufficient electromagnetic wave shielding characteristics can be obtained. Further, if necessary, the electromagnetic wave shielding material 10 that can easily form the metal layer 8 provided by electroplating can be provided in a mode with good electromagnetic wave shielding characteristics. Furthermore, it is possible to manufacture the electromagnetic shielding material 10 that does not cause problems such as disconnection, shape failure, and low adhesion due to poor transfer of the conductive composition 2 '.

Moreover, according to the manufacturing method of the electromagnetic wave shielding material 10, the cross-sectional shape of the convex pattern layer 2 after transfer reproduces the concave shape of the intaglio relatively well. For example, if a version of the depth of the intaglio 20 [mu] m, although the volume shrinkage during drying of the convex pattern layer 2 after transfer, to form a convex pattern layer pattern of about 20 [mu] m close thickness T _C it can. The intaglio recess shape transition rate by this method (defined by [the height of the convex pattern which has been transferred and cured / the depth of the plate recess] × 100 [%]) is also the cure shrinkage rate of the conductive composition. Since it depends, it cannot be generally stated, but usually a value of about 90% or more is obtained. These phenomena are unthinkable in conventional intaglio (gravure) printing. In the case of conventional intaglio printing, even if printing is performed using the same conductive composition, the intaglio recess shape transition rate is usually at most in the case of a conductive composition having low fluidity as used in the present invention. It is about 20%.

  In the present invention, it is not yet clear about the cause of such a metastatic improvement effect. However, as a result of investigating the experimental results, the primer layer 6 and the convex pattern layer 2 are stained in the cross-sectional TEM analysis. As a result of observation, as described above, the interface between the convex pattern layer 2 after the transition and the primer layer 6 is not clearly divided into two layers, and a form that is compatible with each other is confirmed. did it. Note that, unlike the top side of the convex pattern layer 2, the distribution of the conductive particles 4 is sparse at the interface, and the conductive particles 4 do not contact each other and exist as if they float in the resin. Was.

  Further, by SIMS (Secondary Ion Mass Spectrometry), (1) the surface of the convex pattern layer pattern to which the conductive composition 2 ′ has been transferred, (2) the portion where the conductive composition 2 ′ has not transferred (opening or The surface of the primer layer of the convex pattern layer non-forming part B), (3) the surface of the coating film obtained by solid-coating only the conductive composition 2 ′ on the transparent substrate 1 and drying, (4) the primer layer 6 Only the surface of the coating film solid-coated and solidified on the transparent substrate 1 was analyzed. As a result, the fragment (molecular fragment) that is not seen in the coating film of the conductive composition 2 ′ of (3) and that can be seen in (4) is detected in both (1) and (2). It was suggested that the components of the primer layer 6 diffused in the conductive composition 2 ′. Considering from these situations, when the fluid primer layer 6 is brought into contact with the conductive composition 2 ′, the boundary portion is compatible and / or the boundary is disturbed, and the primer layer 6 is solidified in this state. In the region from the boundary portion toward the conductive composition 2 ′, a phenomenon such as thickening or gelation of the conductive composition 2 ′ occurs, and the conductive composition 2 ′ is easily pulled out from the plate. It is guessed that.

  Further, when the primer layer 6 is solidified by mixing a part of the components constituting the flowable primer layer 6 with the uncured conductive composition 2 ′ in the intaglio recess, the viscosity of the conductive composition 2 ′ is increased. May increase overall. In any case, if the flowable primer layer 6 is brought into contact with the conductive composition 2 'and at least the primer layer 6 is solidified and then peeled off, the conductive composition 2' is not completely solidified. Nevertheless, almost 100% transfer was possible.

[Optical filter]
Although the electromagnetic wave shielding material 10 according to the present invention can be used alone, various functional layers may be laminated on the front surface, back surface, or both front and back surfaces of the electromagnetic wave shielding material 10. An optical functional layer can be cited as such a functional layer, and it can be used as an optical filter having both an electromagnetic wave shielding function and an optical function. As the optical functional layer, conventionally known near-infrared absorbing layer, neon light absorbing layer, toning layer, ultraviolet absorbing layer, so-called thin film microlouver layer, antireflection layer and antiglare layer described in JP-A-2007-272161, etc. Etc. Further, if necessary, functional layers such as an impact resistant layer, an antistatic layer, a hard coat layer, an antibacterial layer, an antibacterial layer, and an antifouling layer can be combined.

  Each functional layer may have each function in the transparent protective layer (not shown) itself, may be provided on the transparent protective layer, or directly on the convex pattern layer or the transparent substrate. It may be provided. Each functional layer is formed by a method of directly forming and a method of bonding a separately formed functional layer. In the case of direct formation, a material that exhibits a function is contained in a transparent protective layer, or a method of applying and forming on a surface to be formed such as a transparent protective layer using a coating apparatus, or a general method such as sputtering or vapor deposition Can be applied.

  As a method for coating and forming, general apparatuses such as gravure (roll) coating, roll coating, comma coating, stencil printing, and die coating can be used, and they are appropriately selected according to the properties of the material and the required coating accuracy. In addition, when forming in a partial area in the plane, pattern formation method at the time of coating such as stencil pattern printing, intermittent coating, stripe coating, etc. A method of peeling or removing a functional layer at an unnecessary portion can be used.

  The functional layer may be a single layer that expresses the function, or a plurality of layers may express the function. Examples of single layers include hard coat function, flattening function, near infrared absorption function, neon light absorption function, ultraviolet absorption function, toning function, antireflection function, antiglare function, anti-shock function, and antistatic function One or a plurality of functions such as an antifouling function may be developed. In the case of a plurality of layers, for example, a flattening layer + an antireflection layer, a hard coat layer + an antireflection layer, a near infrared absorption layer + an ultraviolet absorption layer + It is possible to share functions such as a hard coat layer.

  In the case where the functional layer is a scratch-resistant function (hard coat) layer, it is preferable that it exhibits a hardness of “H” or higher in a pencil hardness test specified by JIS K 5600-5-4 (1999). The material is not particularly limited as long as such hardness and transparency similar to the above-described transparent substrate can be realized. As the curable resin to be used, an ionizing radiation curable resin, other known curable resins, or the like may be appropriately employed according to required performance. Examples of the ionizing radiation curable resin are illustrated in the description of the material of the primer layer, and are omitted here.

[Usage]
The electromagnetic wave shielding material 10 according to the present invention can be used for various applications. In particular, PDP, CRT, LCD, EL, etc. used in various television receivers, measuring instruments, measuring instruments, office equipment, medical equipment, amusement equipment, computing equipment, telephones, display parts of electrical signs, etc. This is suitable for a front filter of the image display apparatus. It is particularly suitable for PDP use. In addition, it can also be used for electromagnetic shielding applications such as windows for buildings such as houses, schools, hospitals, offices, stores, etc., windows for vehicles such as vehicles, airplanes and ships, and windows for various home appliances such as microwave ovens. It is.

  Examples The present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[Example 1]
(Preparation of intaglio)
First, as an intaglio roll, an intaglio plate cylinder in which concave portions forming a grid-like mesh pattern having a line width (recess width) of 10 μm, a line pitch (recess pitch) of 300 μm, and a line height (recess depth) of 10 μm are formed. Got ready.

(Preparation of transparent substrate)
As the transparent substrate 1, a 1000 m roll-wrapped polyethylene terephthalate (PET) film having a width of 1000 mm and a thickness of 100 μm and subjected to a polyester resin-based easy adhesion treatment on one side was used. Using the apparatus of the form shown in FIG. 10, the PET film is unwound from a take-up roll set in the supply section, and the UV curable resin composition for the primer layer is applied on the easy-adhesion treated surface to a thickness of 14 μm after curing. did. As a coating method, a normal gravure reverse method was adopted. The UV curable resin composition includes 35 parts by mass of epoxy acrylate, 12 parts by mass of urethane acrylate, 44 parts by mass of monofunctional monomer composed of phenoxyethyl acrylate, 9 parts by mass of trifunctional monomer composed of ethylene oxide-modified isocyanuric acid triacrylate, and light. As the initiator, 1-hydroxy-cyclohexyl-phenyl-ketone (trade name: Irgacure 184, manufacturer: Ciba Specialty Chemicals Co., Ltd.) with 3 parts by mass was used. The volatile drying solvent was not added. The viscosity at this time was about 1300 cps (at 25 ° C., B-type viscometer), and the primer layer 6 after application showed fluidity when touched, but did not flow down from the PET film. Thus, a transparent substrate on which the primer layer 6 having a coating thickness of about 14 μm was formed was prepared.

(Manufacture of electromagnetic shielding material)
As shown in FIG. 10, the conductive composition is applied to the plate surface of the prepared intaglio roll with a pick-up roll, and the conductive composition other than the inside of the recess is scraped off with a doctor blade, and the conductive composition is only in the recess. Was filled. At this time, the conductive composition filled in the recesses had dents 17 on the surface thereof as shown in FIG. A transparent base material (PET film) in which a primer layer is formed between an intaglio roll filled with a conductive composition in a recess and a nip roll is supplied with the primer layer facing the intaglio side. The primer layer is caused to flow into the recess of the conductive composition existing in the recess by the pressing force (biasing force) of the nip roll against the intaglio roll, and the conductive composition and the primer layer are closely adhered to each other, and the primer layer A part of the resin was infiltrated into the conductive composition in the recess. In addition, the used conductive composition used the silver paste of the following compositions.

  Silver paste: 83 parts by weight of spherical silver particles having an average particle diameter of 1 μm as conductive particles, 5 parts by weight of thermoplastic acrylic resin as binder resin, and 12 parts by weight of butyl carbitol as solvent are mixed thoroughly and mixed. Thereafter, a silver paste prepared as a conductive composition by kneading with three rolls. Here, the average particle diameter is a value evaluated by a laser light diffraction scattering method.

  Thereafter, as shown in FIG. 10, the primer layer made of the ultraviolet curable resin composition was cured by irradiating ultraviolet rays with an ultraviolet lamp of a high pressure mercury lamp while rotating the intaglio roll. By curing the primer layer, the uncured conductive composition in the recesses of the intaglio roll was brought into close contact with the primer layer, and then the PET film was released from the intaglio roll by the nip roll on the outlet side. On the primer layer of the released PET film, the uncured conductive composition layer was transferred as a convex pattern layer and printed. The printed film thus obtained was passed through a drying zone at 110 ° C. to evaporate the solvent of the silver paste and solidified to form a convex pattern layer made of a conductive composition layer on the primer layer. An electromagnetic shielding material was produced.

(Evaluation and results)
The dimensions of the formed convex pattern layer were a line width of 10 μm, a line pitch of 300 μm, and a line height H of 10 μm. At this time, the height H of the pattern portion A where the convex pattern layer 2 is present (the difference in thickness between the mesh pattern portion where the convex pattern layer is formed and the other portions) is 9 μm, and the depth of the plate The thickness of 90 mm (10 μm) was transferred from the plate, and the silver paste in the recesses of the plate was transferred at a transfer rate of 90%. When the inside of the concave portion after the transition was observed, there was very little silver paste remaining, and no mesh pattern disconnection or shape defect was observed.

With respect to the electromagnetic wave shielding material at this stage, observation was performed by a transmission electron microscope (TEM) of transverse cut surfaces at 10 different locations of the pattern portion A of the convex pattern layer 2. In the form shown in FIG. 5, the convex pattern layer 2 has a lump portion 3 in which at least 48 conductive particles 4 in total, at least 8 in the horizontal direction and at least 8 in the height direction are in contact with each other. It was. Further, all of the lump portions 3 are located in the top portion direction of the convex pattern layer 2 and constitute the dense region Q of the conductive particles 4 including the lump portion 3. On the other hand, on the primer layer side of the convex pattern layer 2, there is a sparse region R of the conductive particles 4, and the conductive particles 4 existed in a manner that they do not contact each other. On the other hand, the dense region Q includes the lump portion 3, but the conductive particles 4 that do not constitute the lump portion 3 are also present in a relatively interparticle contact state as shown in FIG. 7A. confirmed. Sparse region R is the thickness of the primer layer side of the thickness T _C of the convex pattern layer 2 1/4, the remaining 3/4 of the thickness T _C was dense region Q. Further, the mass 3 accounted for 60% of the volume of the dense region Q.

  Further, when the cross section of the convex pattern layer 2 is dyed with an osmium staining solution, the interface between the primer layer and the dyed convex pattern layer is like a gradation (light gray scale) as shown in FIG. 8C. Further, as shown in FIG. 8 (A), the structure of the interface between both layers was observed in detail, and it was clearly confirmed that a part of the boundary part was familiar (compatible).

  In addition, when the surface portion on the convex pattern layer side was subjected to secondary ion mass spectrometry (SIMS analysis), a resin composition component that was not contained in the conductive composition but was contained in the primer layer was observed. It was confirmed that a part of the resin composition component penetrated into the conductive composition layer before curing. Considering these situations, when a fluid primer layer comes into contact with the conductive composition, compatibility and / or disturbance of the boundary portion occurs, and when the primer layer is solidified in this state, It was speculated that a phenomenon such as thickening or gelation of the conductive composition occurred in the region from the portion toward the inside of the conductive composition, and the conductive composition could be easily pulled out from the plate. Or, a part of the resin composition component of the fluid primer layer is mixed with the conductive composition in the plate, and when the primer layer is solidified, the viscosity of the conductive composition is generally increased. Inferred. In any case, if the primer layer with fluidity is brought into contact with the conductive composition and the primer layer is solidified and then peeled, the conductive composition is not completely solidified in the plate recess. , Close to 100% transfer was possible.

The electrical resistance of the convex pattern layer 2 was evaluated by surface resistivity (Ω / □) in a room temperature atmosphere (temperature 23 ° C., relative humidity 50%). The surface resistivity was measured by bringing a measurement probe into contact with the top of the convex pattern layer 2 and found to be 3.0Ω / □. The results are shown in Table 1. In addition, since the maximum scale (upper limit of the measurement range) of the surface resistance meter used was 1900000 (1.9 × 10 ⁶ ) Ω / □, when the measured value displayed a value exceeding the maximum scale, “1. 9 × 10 ⁶ ) Ω / □ exceeded ”.

[Example 2]
An electromagnetic wave shielding material of Example 2 was produced in the same manner as in Example 1 except that the following silver paste was used in Example 1. The results are shown in Table 1. The bonding form between the particles was as shown in FIG.

  Silver paste: 83 parts by mass of flaky silver particles having an average particle diameter of 2 μm as conductive particles, 5 parts by mass of thermoplastic acrylic resin as binder resin, and 12 parts by mass of butyl carbitol as solvent are mixed thoroughly. After that, a silver paste prepared as a conductive composition by kneading with three rolls. The average particle size of the scaly silver particles is a value evaluated by a laser light diffraction scattering method.

[Example 3]
In Example 1, after manufacturing the electromagnetic shielding material formed by forming the convex pattern layer composed of the conductive composition layer on the primer layer, the electric resistance reduction treatment was subsequently performed under the following high temperature and high humidity conditions. It was. Other than that was carried out similarly to Example 1, and manufactured the electromagnetic shielding material of Example 3. FIG. The results are shown in Table 1. The bonding form between the particles was as shown in FIG.

  High-temperature and high-humidity conditions: The obtained electromagnetic shielding material was left in an atmosphere at a temperature of 80 ° C. and a relative humidity of 90% for 48 hours and taken out into a room temperature atmosphere (temperature 23 ° C., relative humidity 50%).

[Example 4]
In Example 2, an electromagnetic wave shielding material formed by forming a convex pattern layer made of a conductive composition layer on a primer layer was manufactured, and subsequently an electrical resistance reduction treatment was performed under the following acid treatment conditions. . Other than that was carried out similarly to Example 2, and manufactured the electromagnetic wave shielding material of Example 4. The results are shown in Table 1. The bonding form between the particles was as shown in FIG.

  Acid treatment conditions: The obtained electromagnetic shielding material was treated with dilute hydrochloric acid (0.12 mol / L) for 1 minute, washed with water and dried, and then taken out.

[Example 5]
In Example 1, as an intaglio roll, an intaglio having a grid-like mesh pattern with a line width (recess width) of 19 μm, a line pitch (recess pitch) of 300 μm, and a line height (recess depth) of 19 μm was formed. A plate cylinder was prepared, and an electromagnetic wave shielding material of Example 5 was manufactured in the same manner as Example 1 except that the following silver paste was used as the silver paste. The results are shown in Table 1. The bonding form between the particles was as shown in FIG.

  Silver paste: 83 parts by weight of spherical silver particles having an average particle size of 4 μm as conductive particles, 5 parts by weight of thermoplastic acrylic resin as binder resin, and 12 parts by weight of butyl carbitol as solvent are mixed thoroughly and mixed. Thereafter, a silver paste prepared as a conductive composition by kneading with three rolls.

[Example 6]
In Example 1, an intaglio roll having indentations forming a grid-like mesh pattern with a line width (recess width) of 6 μm, a line pitch (recess pitch) of 300 μm, and a line height (recess depth) of 6 μm was formed as the intaglio roll. A plate cylinder was prepared, and an electromagnetic wave shielding material of Example 6 was produced in the same manner as in Example 1 except that the following silver paste was used as the silver paste. The results are shown in Table 1. The bonding form between the particles was as shown in FIG.

  Silver paste: 83 parts by weight of spherical silver particles having an average particle diameter of 1 μm as conductive particles, 5 parts by weight of thermoplastic acrylic resin as binder resin, and 12 parts by weight of butyl carbitol as solvent are mixed thoroughly and mixed. Thereafter, a silver paste prepared as a conductive composition by kneading with three rolls.

[Example 7]
In Example 5, after manufacturing the electromagnetic wave shielding material, the electrical resistance reduction treatment was subsequently performed under the following conditions. Other than that was carried out similarly to Example 5, and manufactured the electromagnetic shielding material of Example 7. The results are shown in Table 1. The bonding form between the particles was as shown in FIG.

  Warm water treatment conditions: The obtained electromagnetic shielding material was immersed in warm water at 80 ° C. for 6 minutes, taken out, and then dried.

[Example 8]
In Example 5, after manufacturing the electromagnetic wave shielding material, the electrical resistance reduction treatment was subsequently performed under the following conditions. Other than that was carried out similarly to Example 5, and manufactured the electromagnetic wave shielding material of Example 8. The results are shown in Table 1. The bonding form between the particles was as shown in FIG.

  Acid treatment conditions: The obtained electromagnetic shielding material was treated with dilute hydrochloric acid (0.25 mol / L) for 1 minute, washed with water and dried, and then taken out.

[Example 9]
In Example 5, intaglio rolls having depressions to form a grid-like mesh pattern having a line width (recess width) of 19 μm, a line pitch (recess pitch) of 300 μm, and a line height (recess depth) of 10 μm were formed as intaglio rolls. A plate cylinder was prepared, and the electromagnetic shielding material of Example 9 was manufactured in the same manner as Example 5 except for that. The results are shown in Table 1. The bonding form between the particles was as shown in FIG.

[Example 10]
In Example 9, after manufacturing the electromagnetic shielding material, the electrical resistance reduction treatment was subsequently performed under the following conditions. Otherwise, the electromagnetic shielding material of Example 10 was produced in the same manner as Example 9. The results are shown in Table 1. The bonding form between the particles was as shown in FIG.

  Acid treatment conditions: The obtained electromagnetic shielding material was treated with dilute sulfuric acid (0.15 mol / L) for 1 minute, washed with water and dried, and then taken out.

[Example 11]
In Example 10, after manufacturing the electromagnetic wave shielding material, subsequently, an electrical resistance reduction treatment was performed under the following conditions. Other than that was carried out similarly to Example 10, and manufactured the electromagnetic shielding material of Example 11. The results are shown in Table 1. The bonding form between the particles was as shown in FIG.

  Warm water treatment conditions: The obtained electromagnetic wave shielding material was treated with warm water at 90 ° C. for 10 minutes, taken out, and then dried.

[Comparative Example 1]
An electromagnetic wave shielding material of Comparative Example 1 was produced in the same manner as in Example 1 except that the following silver paste was used in Example 1. The results are shown in Table 1. The bonding form between the particles was as shown in FIG.

  Silver paste: 83 parts by weight of spherical silver particles having an average particle size of 3 μm as conductive particles, 5 parts by weight of thermoplastic acrylic resin as binder resin, and 12 parts by weight of butyl carbitol as solvent are mixed thoroughly and mixed. Thereafter, a silver paste prepared as a conductive composition by kneading with three rolls.

[Comparative Example 2]
An electromagnetic wave shielding material of Comparative Example 2 was produced in the same manner as in Example 1 except that the following silver paste was used in Example 1. The results are shown in Table 1. The bonding form between the particles was as shown in FIG.

  Silver paste: 83 parts by weight of spherical silver particles having an average particle diameter of 5 μm as conductive particles, 5 parts by weight of thermoplastic acrylic resin as binder resin, and 12 parts by weight of butyl carbitol as solvent are mixed thoroughly and mixed. Thereafter, a silver paste prepared as a conductive composition by kneading with three rolls.

[Comparative Example 3]
In Example 1, as an intaglio roll, an intaglio having a grid-like mesh pattern with a line width (recess width) of 19 μm, a line pitch (recess pitch) of 300 μm, and a line height (recess depth) of 19 μm was formed. A plate cylinder was prepared, and an electromagnetic wave shielding material of Comparative Example 3 was produced in the same manner as in Example 1 except that the following silver paste was used as the silver paste. The results are shown in Table 1. The bonding form between the particles was as shown in FIG.

  Silver paste: 83 parts by weight of spherical silver particles having an average particle size of 4 μm as conductive particles, 5 parts by weight of thermoplastic acrylic resin as binder resin, and 12 parts by weight of butyl carbitol as solvent are mixed thoroughly and mixed. Thereafter, a silver paste prepared as a conductive composition by kneading with three rolls.

[Comparative Example 4]
In Example 9, the electromagnetic wave shielding material of Comparative Example 4 was produced in the same manner as Example 9 except that the average particle size of the conductive particles was 3 μm. The results are shown in Table 1. The bonding form between the particles was as shown in FIG.

[Comparative Example 5]
In Comparative Example 4, as an intaglio roll, an intaglio in which recesses that form a grid-like mesh pattern having a line width (recess width) of 6 μm, a line pitch (recess pitch) of 300 μm, and a line height (recess depth) of 6 μm are formed. An electromagnetic wave shielding material of Comparative Example 5 was produced in the same manner as Comparative Example 4 except that the plate cylinder was prepared. The results are shown in Table 1. The bonding form between the particles was as shown in FIG.

[Comparative Example 6]
In Comparative Example 4, as an intaglio roll, an intaglio plate having a grid-like mesh pattern with a line width (recess width) of 19 μm, a line pitch (recess pitch) of 300 μm, and a line height (recess depth) of 19 μm was formed. An electromagnetic wave shielding material of Comparative Example 6 was produced in the same manner as Comparative Example 4 except that the plate cylinder was prepared. The results are shown in Table 1. The bonding form between the particles was as shown in FIG.

DESCRIPTION OF SYMBOLS 1 Transparent base material 2 Convex pattern layer 2 'Conductive composition (conductive composition layer)
DESCRIPTION OF SYMBOLS 3 Lump part 4 Conductive particle 5 Binder resin 6 Primer layer 7 Swelling part 8 Metal layer 9 Side edge 10 (10A-10C) Electromagnetic wave shielding material 11 Electromagnetic wave shielding pattern part 12 Grounding part 13 Interface 14 Mixing area 16 Primer component 17 Recess 18 Contact portion 19 Joint portion 31 Pickup roll 32 Intaglio roll 33 Plate surface 34 Recess 35 Doctor blade 36 Nip roll 37 Nip roll 38 Filling container 40 Intaglio 41 Pickup roll 42 Primer layer resin composition 43 Container 44 Wiping roll H Convex pattern layer height (thickness)
A A portion where the conductive material layer is formed T _{A A} A thickness B A portion where the conductive material layer is not formed T _B B thickness T _C Height (thickness) of the convex pattern layer
Q Dense part R Sparse part W Line width

Claims (6)

  It has a transparent substrate and a convex pattern layer made of a conductive composition formed on the transparent substrate, and the conductive composition has a length equal to or less than ¼ of the line width of the convex pattern layer. Conductive particles having a mean particle size and a binder resin, wherein at least one transverse cut surface of the convex pattern layer has a lump portion in which 16 or more conductive particles are in contact with each other. An electromagnetic shielding material.   2. The electromagnetic shielding material according to claim 1, wherein the lump part is in contact with each other at least 4 in the vertical direction and 4 in the horizontal direction.   The distribution of the conductive particles in the convex pattern layer is relatively sparse on the transparent substrate side, and is relatively dense with the lump on the side away from the transparent substrate. Item 3. The electromagnetic shielding material according to Item 1 or 2.   The electromagnetic wave shielding material according to claim 3, wherein the sparsely distributed regions have conductive particles present in the binder resin without being in contact with each other.   The electromagnetic wave shielding material according to claim 1, wherein the convex pattern layer has a surface resistivity of 10Ω / □ or less.   There is a primer layer on the surface of the transparent substrate on the side where the convex pattern layer is provided, and the thickness of the portion of the primer layer where the convex pattern layer is formed is such that the convex pattern layer is The electromagnetic wave shielding material according to any one of claims 1 to 5, wherein the electromagnetic shielding material is thicker than a thickness of a portion not formed.

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