JP2009044005A - Electromagnetic wave shielding member for plasma display and method for manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic wave shielding member for a plasma display in which a pattern having conductivity is formed by transferring conductive pastes, etc., on a transparent substrate, and in which an electromagnetic wave shielding pattern is formed with precision without causing troubles such as pattern breakage owing to the transition failure of the conductive pastes, etc., defective form, and low adhesion, and curls are suppressed and no troubles are caused in subsequent processes. <P>SOLUTION: The electromagnetic wave shielding member for a plasma display is characterized in that a primer layer is made of ionizing radiation hardened resin, the part of the primer layer at which a conductive layer is formed is thicker than the part at which no conductive layer is formed, and on the surface of the transparent substrate on which the primer layer is not formed, a curl preventing layer is formed and thereby the curl value of the electromagnetic shielding member is ≤20 mm. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

  Among display devices such as televisions (visions) and personal computer monitors, plasma display devices that are attracting attention in the field of large-screen display devices use plasma discharge for light emission, and therefore generate unnecessary electromagnetic waves in the 30 MHz to 1 GHz band. There is a risk of leaking outside and affecting other devices (for example, remote control devices, information processing devices, etc.). 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.

Examples of the electromagnetic wave shielding material that can be used for the front surface of a plasma display include a silver sputtered thin film and a copper mesh. However, the silver sputtered thin film is expensive and has poor transparency because it covers the entire surface. Since the copper mesh has an opening, the transparency is high, but the copper foil is etched by a photolithography method to create a mesh shape.
In recent years, an electromagnetic wave shielding member has been proposed in which an ink containing a conductive paste or an electroless plating catalyst is printed on a transparent substrate and copper is deposited on the transparent substrate to form a fine line pattern (patent) Literatures 1-3).

Ink used in such pattern printing is usually a high-viscosity ink having thixotropy in order to increase printing accuracy, and a method such as screen printing (Patent Document 1) is used. However, with screen printing, it is difficult to print with roll-to-roll, and the plate itself is stretched with a strong tension, so that there is a problem that the accuracy of the periphery of the plate is poor when the area is large.
In addition, when trying to print such an ink with a fine pattern by a method using a plate having a concave portion as in gravure printing (Patent Documents 2 and 3), the ink cannot be printed but the ink transferability is poor and the ink is missing. There was a problem that a stable pattern could not be formed. This is because the ink in the recess after applying ink on the intaglio and scraping off excess ink with a doctor blade causes a dent in the upper part. This depression prevents the adhesion of the transparent substrate and the ink when the transparent substrate is pressed onto the intaglio plate and the ink in the recess is transferred onto the transparent substrate, and the ink is not transferred onto the transparent substrate. Part or a transfer failure inferior in adhesiveness occurs, and the electromagnetic shielding characteristics are deteriorated.

The present inventors who examined the solution of the problem of ink transfer (transfer) failure in intaglio printing applied a liquid resin composition that is cured by ionizing radiation such as UV and EB as a primer on a transparent substrate, It was found that the paste was almost completely transferred onto the substrate by irradiating ionizing radiation with the primer-coated surface facing the intaglio surface filled with the paste and curing the primer. By using this method, a paste containing a conductive material and a catalyst can be efficiently and accurately printed on the substrate.
However, at this time, the primer layer curls due to the shrinkage of the ionizing radiation curable primer during curing (causes warping), and the electromagnetic wave shielding member curls in such a direction that the primer layer side is bent into a concave surface. I found out that It was also found that when the production of the electromagnetic shielding member includes a wet process such as a plating bath, the ionizing radiation curable resin shrinks after moisture drying, the primer layer curls, and the electromagnetic shielding member may curl. . If the degree of curling of these electromagnetic wave shielding members is large, a great inconvenience is caused in the subsequent process of using the electromagnetic wave shielding member such as sticking to a plasma display panel.

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

  An object of the present invention is an electromagnetic wave shielding member for a plasma display that forms a pattern having conductivity by transferring a conductive paste or the like onto a transparent substrate, and the pattern breakage based on a transfer defect such as the conductive paste, To provide an electromagnetic wave shielding member for a plasma display in which an electromagnetic wave shielding pattern is accurately produced without causing defects such as shape defects and low adhesion, and curling is suppressed and no trouble occurs in a subsequent process. .

  As a result of investigations for achieving the above object, the inventors of the present invention are an electromagnetic wave shielding member for a plasma display having a transparent substrate, a primer layer, and a conductive layer, and the primer layer has a specific shape. Further, the present inventors have found that an electromagnetic wave shielding member having an anti-curl layer on the transparent substrate surface on the side where the primer layer is not formed solves the above problems, and has completed the present invention.

  That is, the present invention relates to an electromagnetic wave shielding member for a plasma display, comprising a transparent substrate, a primer layer formed on one surface of the transparent substrate, and a conductive layer formed in a predetermined pattern on the primer layer. The primer layer is made of a cured product of an ionizing radiation curable resin, and the thickness of the portion of the primer layer where the conductive layer is formed is greater than the thickness of the portion where the conductive layer is not formed. The surface of the transparent substrate on which the primer layer is not formed is formed by coating and curing a composition having curing shrinkage (an anti-curl layer), The curl value of the electromagnetic wave shielding member is 20 mm or less, and an electromagnetic wave shielding member for plasma display is provided.

  Here, in the primer layer provided on the transparent substrate, the thickness of the portion where the conductive layer is formed is larger than the thickness of the portion where the conductive layer is not formed. This means that a primer layer is provided. The primer layer having such a form is formed on the basis of being filled in an upper recess such as a conductive paste in a recess of a plate after scraping with a doctor blade at the time of manufacturing an electromagnetic shielding member. Thus, an electromagnetic wave shielding member is provided in which the primer layer adheres to the conductive paste or the like without a gap, and defects such as disconnection, shape failure, and low adhesion due to transfer failure of the conductive paste or the like do not occur.

  According to the form of the primer layer of the electromagnetic wave shielding member of the present invention, since the primer layer is provided so as to fill the dent of the conductive layer generated on the plate surface, it is based on poor transfer of the conductive paste or the like. It is possible to provide an electromagnetic wave shielding member for plasma display that does not cause defects such as pattern disconnection, shape defect, and low adhesion. Furthermore, since curling is suppressed by having the anti-curl layer, there is provided an electromagnetic wave shielding member for plasma display that does not cause problems in manufacturing and assembly.

An example of the electromagnetic wave shielding member of the present invention is shown in FIGS. FIG. 1 is a plan view of an electromagnetic wave shielding member, and FIG. 2 is an enlarged view of the AA ′ cross section in FIG. 1. FIG. 3 is a schematic cross-sectional view showing the shape of the primer layer further enlarging a part of FIG. The electromagnetic wave shielding member 10 of the present invention includes a transparent substrate 1, a primer layer 2 having a specific shape formed on one side of the transparent substrate 1, and a conductive layer (conductive) formed in a predetermined pattern on the primer layer. And the anti-curl layer 5 on the other surface of the transparent substrate. It is what has. Moreover, you may have the protective layer 6 as needed.
Here, the “predetermined pattern” is a mesh-like or stripe-like pattern that is common as an electromagnetic wave shielding pattern of the electromagnetic wave shielding member.
Moreover, the three aspects of the conductive layer of the electromagnetic wave shielding member 10 of the present invention are as follows.
The first conductive layer is a conductive material layer 3 made of conductive fine particles and a binder resin, and the second conductive layer is one in which a metal layer 4 is further formed on the surface of the conductive material layer 3. In the third conductive layer, a metal layer 4 is formed on the surface of a catalyst layer 3 ′ made of an electroless plating catalyst, a carrier, and a binder resin.
Hereinafter, the configuration of the electromagnetic wave shielding member of the present invention will be described in detail.

(Transparent substrate)
The transparent base material 1 is a base material for the electromagnetic wave shielding member 10 and is selected from various thicknesses of various materials in consideration of required transparency such as desired transparency, mechanical strength, and adhesion to the primer layer 2. That's fine. Resin, glass or the like is used as the material, and a film (or sheet) or plate is used as the thickness. Usually, a resin transparent film is preferably used.
Such a transparent film is preferably a film based on acrylic resin, polyester resin or the like, but is not limited thereto. Specific examples of the film material include cellulose resins such as triacetyl cellulose, diacetyl cellulose, and acetate butyrate cellulose, poly (meth) methyl acrylate, methyl (meth) acrylate-butyl (meth) acrylate Acrylic resins such as coalescence (“(meth) acrylic acid” means acrylic acid or methacrylic), polyester resins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethylene, polypropylene, cyclic polyolefin, trimethyl Polyolefin resins such as pentene, halogen-containing resins such as polyvinyl chloride and polyvinylidene chloride, styrene resins such as polystyrene and acrylonitrile-styrene copolymers, polyethersulfone, polyurethane resins, polycarbonate DOO resins, polyamide resins, polysulfone resins, polyether resins, polyether ketone resins, (meth) acrylonitrile resins can be used. Among them, the biaxially stretched PET film is preferable in that it has excellent transparency and durability, and has heat resistance that does not cause thermal deformation even when it is subjected to ionizing radiation irradiation treatment in the subsequent steps.

The transparent substrate 1 may be a strip-like long film that is used by being unwound from a roll (winding), or may be a sheet film having a predetermined size. The thickness of the transparent substrate 1 is usually preferably about 10 μm to 5000 μm, but is not limited thereto. The light transmittance of the transparent substrate 1 is ideally 100%, but it is preferable to select a light transmittance of 80% or more.
If necessary, the surface of the transparent substrate may be provided with an easy-adhesion layer to improve the adhesion between the primer layer and the substrate, which will be described later, or may be subjected to surface treatment such as corona discharge treatment, plasma treatment, or flame treatment. You may go. The easy-adhesion layer is composed of a resin having adhesiveness to both the transparent substrate 1 and the primer layer 2. The resin for the easy adhesion layer is appropriately selected from resins such as urethane resin, epoxy resin, polyester resin, acrylic resin, and chlorinated polypropylene.

(Primer layer)
The primer layer 2 is provided on the transparent substrate 1 with good adhesion. On the primer layer 2, the conductive material layer 3 or the catalyst layer 3 'is provided with good adhesion. Therefore, the primer layer 2 is preferably a material having good adhesion to both the transparent substrate 1 and the conductive material layer 3 or the catalyst layer 3 ′, and of course, it is preferably transparent. . In the present invention, a layer formed by coating and curing an ionizing radiation curable composition containing an ionizing radiation polymerizable compound is used.
As the ionizing radiation polymerizable compound, a monomer and / or a prepolymer that is polymerized and cured by a reaction such as crosslinking upon irradiation with ionizing radiation is used.
Examples of such a monomer (also referred to as a trimer) include radically polymerizable monomers such as methyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, and isobornyl (meth). Monofunctional (meth) acrylates such as acrylate, dicyclopentenyl (meth) acrylate, dipropylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, tri Various (meth) acrylates such as polyfunctional (meth) acrylates such as methylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, and dipentaerythritol hexa (meth) acrylate Examples of cationic polymerizable monomers include alicyclic epoxides such as 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate, glycidyl ethers such as bisphenol A diglycidyl ether, 4-hydroxybutyl, and the like. Examples include vinyl ethers such as vinyl ether and oxetanes such as 3-ethyl-3-hydroxymethyloxetane.
Such prepolymers (also referred to as oligomers) include radically polymerizable prepolymers such as various (meth) acrylate prepolymers such as urethane (meth) acrylate, epoxy (meth) acrylate, polyester (meth) acrylate, and the like. And saturated polyester prepolymers. Other examples of the cationic polymerizable prepolymer include novolac type epoxy resin prepolymer and aromatic vinyl ether type resin prepolymer.
These monomers or prepolymers may be used alone or in combination of two or more types of monomers, two or more types of prepolymers, or one type of monomer, depending on the required performance, coating suitability, etc. A mixture of the above and one or more prepolymers can be used.
The ionizing radiation is typically ultraviolet (UV) or electron beam (EB), but other than this, electromagnetic waves such as visible light, X-rays and γ-rays, or charged particles such as α-rays. Lines can also be used.

  When ultraviolet rays or visible rays are used as the ionizing radiation, a photopolymerization initiator is usually added. When other things such as an electron beam are used as the ionizing radiation, the photopolymerization initiator is unnecessary. As a photopolymerization initiator, in the case of a radical polymerizable monomer or prepolymer, a compound such as a benzophenone-based, thioxanthone-based, or benzoin-based compound, or in the case of a cationic polymerization-based monomer or prepolymer, a metallocene-based compound, 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 mass with respect to 100 parts by mass of the composition comprising the monomer and / or prepolymer.

In addition, the ionizing radiation curable composition may use various additives and modified resins for improving adhesion, durability, and imparting various physical properties. Examples of the additive include a heat stabilizer, a radical scavenger, a plasticizer, a surfactant, an antioxidant, an ultraviolet absorber, an infrared absorber, a dye (colored dye, colored pigment), and an extender. .
The ionizing radiation curable composition may contain a solvent, but in that case, since a drying step is necessary after coating, it is preferable that the composition does not contain a solvent (so-called non-solvent type).

  The present invention is characterized in that the ionizing radiation curable primer layer 2 and the state (flow state and cured state) of the primer layer are appropriately used. Specifically, the ionizing radiation curable primer layer is provided on the transparent substrate 1 in a fluid state (liquid state) after coating, and the ionizing radiation curable primer layer is cured to be non-flowable. After solidifying, the conductive paste or the catalyst paste is transferred. Therefore, the ionizing radiation curable primer layer needs to be able to change from the fluidized state to the cured state in a short time to form the primer layer 2. By forming the primer layer 2 on the transparent substrate 1 in this way, when transferring the conductive paste or catalyst paste onto the primer layer 2, the conductive paste layer or catalyst paste layer and the primer layer 2 Since there is no gap between the conductive paste layer or the catalyst paste layer and the primer layer 2, which may have occurred in the past, it is possible to eliminate the gap, and the existence of the gap. The problem of transfer failure and contact failure due to the ink does not occur.

As used herein, the term “fluidity” or “fluid state” refers to the property of flowing (deforming) by pressure when the ionizing radiation curable primer layer is pressure-bonded to a plate surface filled with a conductive paste or a catalyst paste. Or it refers to the condition and does not need to be as low as water. The viscosity may be adjusted to be suitable for coating, and may flow (deform) after application on the transparent substrate, and the ionizing radiation-curable primer layer may be at a temperature at which it flows (deforms) during pressure bonding. In this case, it may be called a softened state.
Further, the conductive paste layer represents an uncured state, and the cured one is called a conductive material layer. Further, the catalyst paste layer represents an ineffective state, and the cured product is called a catalyst layer. An uncured layer made of an ionizing radiation curable composition for forming a primer layer is called an ionizing radiation curable primer layer.

The shape of the primer layer 2 in the electromagnetic wave shielding member of the present invention is shown in FIG. The thickness T _A of the portion _A where the conductive material layer 3 or the catalyst layer 3 ′ is formed (same as the portion where the conductive layer is formed) is the same as the thickness T _A of the conductive material layer 3 or the catalyst layer 3 ′. greater than the thickness T _B of the portion without B (same as the portion where the conductive layer is not formed).
In the embodiment shown in FIG. 3, after the ionizing radiation curable primer layer is pressure-bonded to the conductive paste or catalyst paste in the intaglio, the ionizing radiation curable primer layer is cured, and then the conductive paste or catalyst paste is transferred. Therefore, it was generated. Moreover, the said form also has the effect of preventing the damage of a conductive layer by contact etc. after a conductive layer is formed.
The thickness of the primer layer (T _{B in} FIG. 3) is preferably 1 to 100 μm, more preferably 1 to 50 μm. If T _B is small, the transferability of the conductive paste or the catalyst paste tends to deteriorate, and if it is large, problems of transparency and curling tend to occur.

(Conductive material layer)
In the first and second aspects of the conductive layer of the electromagnetic wave shielding member of the present invention, the conductive material layer 3 is provided on the primer layer 2 in a predetermined pattern. The pattern may be a mesh shape or a stripe shape that is usually employed for the electromagnetic wave shielding member, and the line width and the pitch between the lines may be dimensions that are usually employed. For example, the line width can be 5 to 30 μm, and the line-to-line pitch can be 100 to 500 μm. In addition to the electromagnetic shielding pattern having a mesh or stripe shape, there may be a case where a grounding pattern such as all adjacent solids is provided while maintaining electrical continuity therewith.
The conductive material layer 3 can be formed in a predetermined pattern on the primer layer 2 by a manufacturing method described later using a conductive paste containing conductive fine particles and a binder resin as a starting material.

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

  The conductive fine particles constituting the conductive paste include low resistivity metal particles such as gold, silver, platinum, copper, tin, nickel and aluminum, and particles whose surfaces are plated with a low resistivity metal such as gold and silver ( High resistivity metal particles, resin particles, inorganic particles), graphite particles, carbon black particles, etc. can be preferably mentioned, and the shape is also selected from spherical, spheroid, polyhedral, scaly, disk, fiber, etc. be able to. These materials and shapes may be appropriately mixed and used. The size of the conductive fine particles is arbitrarily selected depending on the type and thus cannot be specified unconditionally. For example, in the case of flaky silver particles, those having an average particle diameter of about 0.1 to 10 μm are used. In the case of carbon black particles, those having an average particle diameter of about 0.01 to 1 μm can be used. The content of the conductive fine particles in the conductive paste is arbitrarily selected according to the conductivity of the conductive fine particles and the form of the particles. For example, out of 100 parts by weight of the solid content of the conductive paste, It can be contained in the range of 40 to 99 parts by weight. In the present application, the average particle diameter refers to a particle size distribution diameter or a value measured by TEM (transmission electron microscope) observation.

Moreover, you may add an appropriate additive to an electrically conductive paste for the purpose of quality improvement. For example, carbon black is not necessary because it is black in itself, but by adding a predetermined amount of black pigment or black dye as necessary, the contrast when an electromagnetic wave shield panel is constructed is improved and visibility is improved. Can be made. Further, in order to prevent reflection on the back surface of the transparent substrate due to the metallic luster of the metal plating layer, which will be described later, and to suppress color unevenness, metal color, etc., it is desirable to contain such a black pigment or black dye. As black pigments, carbon black, Fe ₃ O ₄ , CuO—Cr ₂ O ₃ , CuO—Fe ₃ O ₄ —Mn ₂ O ₃ , CoO—Fe ₂ O ₃ —Cr ₂ O _{3 which} also function as conductive powder The type and shape are not particularly limited, and a black pigment or black dye having a large coloring power with an average particle diameter of 0.1 μm or less that can be easily dispersed in the binder resin is preferable. In addition, when using carbon black, carbon black for coloring materials such as channel black, furnace black or lamp black, conductive carbon black, acetylene black and the like can be mentioned, and among them, the average particle diameter is 20 nm or less. Is preferably used. As the black dye, a dye such as aniline black can be used.
Also, in order to improve the fluidity and stability of the conductive paste, fillers, thickeners, surfactants, antioxidants, etc. are appropriately added as long as they do not adversely affect the conductivity and adhesion with the primer layer. It may be added.

(Catalyst layer)
In the third aspect of the conductive layer of the electromagnetic wave shielding member of the present invention, a catalyst layer 3 ′ is provided on the primer layer 2 in a predetermined pattern instead of the conductive material layer 3. The shape of the pattern, its line width, inter-line pitch and other dimensions are the same as in the case of the conductive material layer 3.
The catalyst layer 3 ′ can be formed in a predetermined pattern on the primer layer 2 by a manufacturing method described later using a catalyst paste containing an electroless plating catalyst and a binder as a starting material.

As an electroless plating catalyst constituting the catalyst paste, ultrafine noble metal particles such as palladium, gold, silver and platinum can be used. Although these particles may be added directly to the paste, they are generally expensive and are usually used in the state of being supported on the surface of another particle.
The electroless plating catalyst carrier is not particularly limited as long as it does not interfere with the catalyst function and the catalyst fine particles do not easily fall off from the support surface. For example, fine alumina gel, silica gel, zeolite, or the like may be used. it can. Examples of the supporting method include a method using colloidal surface adsorption, a method using a mechanochemical reaction, a physical method such as vapor deposition and sputtering, and the method is not limited.
The binder (binder) added to the catalyst paste is not particularly limited as long as it has resistance to the plating solution, which is a subsequent process. For example, cellulose derivatives such as ethyl cellulose and nitrocellulose, acrylics, and vinyl acetates. , PVA, polyester, polyurethane and the like can be used. These may be used alone or in combination.
The solvent used in the catalyst paste is not particularly limited as long as it can dissolve the binder well. However, a solvent having a relatively high boiling point is preferable in order to avoid the influence of volatilization at the time of printing. It can be illustrated.
The viscosity of the catalyst paste is usually in the range of several hundred mPa · s to several hundred thousand mPa · s, and the one having pseudo-viscous flow (thixotropic property) It is preferable from the viewpoint of maintaining the stability of the pattern shape. Usually, a paste in which fine particles such as silica gel are dispersed is suitable for use since it exhibits thixotropic properties.
The catalyst paste may contain a black pigment in order to prevent reflection on the back surface of the transparent substrate due to the metallic luster of the plating film and to suppress color unevenness and metal color. The black pigment in this case is preferably a black pigment having a large coloring power and having a particle diameter of 0.1 μm or less that can be easily dispersed in the paste. For example, carbon black, Fe ₃ O ₄ , CuO—Cr ₂ O ₃ , CuO—Fe ₃ O ₄ —Mn ₂ O ₃ , CoO—Fe ₂ O ₃ —Cr ₂ O _{3 and the} like can be used. In particular, carbon black is preferable.

(Metal layer)
In the first aspect of the conductive layer of the electromagnetic wave shielding material of the present invention, if the conductive material layer 3 alone is insufficient for the desired conductivity, the metal layer 4 is added as necessary in order to further improve the conductivity. It can be formed (second embodiment of the conductive layer of the present invention), and is formed on the conductive material layer 3 by plating. It is noted that the metal layer formed by such plating can be deposited only on the surface of the conductive material layer 3, but the conductive material layer 3 is made to have a porous structure having minute voids therein, It is also possible to deposit a gold layer and connect the conductive fine particles with a plated metal plate.
There are electroplating and electroless plating methods as plating methods, but electroplating can increase the plating rate several times by increasing the amount of electricity compared to electroless plating, which significantly improves productivity. This is preferable.
In the case of electroplating, power supply to the conductive material layer 3 is performed from an electrode such as a current-carrying roll brought into contact with the surface on which the conductive material layer 3 is formed. The conductive material layer 3 can be electroplated. Since it has conductivity (for example, 100Ω / □ or less), electroplating can be performed without any problem. Examples of the material constituting the metal layer 4 include copper, silver, gold, chromium, nickel and the like, which have high conductivity and can be easily plated.
Since the metal layer generally has a volume resistivity smaller than that of the conductive material layer 3 by one digit or more, the amount of the conductive material required can be reduced as compared with the case where the conductive layer alone secures electromagnetic wave shielding properties. There are advantages.

In the third aspect of the conductive layer of the electromagnetic wave shielding material of the present invention, the metal layer 4 is formed on the catalyst layer 3 ′ by electroless plating or the like.
For electroless plating, a general electroless plating solution can be used. As the metal that can be used, one or more of gold, silver, copper, nickel, tin, zinc, and cobalt can be used. Is preferably gold, silver, copper, nickel or the like. For example, an electroless copper plating bath, an electroless nickel-phosphorous plating bath, an electroless nickel-boron plating bath, or the like can be used.
Since electroless plating is deposited only on the portion where the catalyst paste is printed, a conductive pattern can be created with high accuracy.
In addition, since electroless plating usually takes time for metal deposition, the necessary conductivity may be imparted by electroplating after ensuring the necessary minimum conductivity by electroless plating. General plating can be used, and gold, silver, copper, nickel, tin, zinc, cobalt and the like can be selected and used, and gold, silver, copper, nickel and the like are preferable from the viewpoint of conductivity.

  In addition, after forming the metal layer 4, the metal layer 4 may be blackened or a protective layer may be provided as necessary. A typical example of the blackening process is a process of laminating a black layer (blackened layer) made of a black metallurgy, an alloy, or a metallurgy compound by blackened nickel plating, copper-cobalt alloy plating, or the like. Other examples include coating treatment of resin paints containing black pigments, oxidation treatment of the surface of the metal layer to black oxide, surface roughening by corrosion of the surface of the surface of the metal layer, and protection. The layer can be formed using, for example, an acrylic photocurable resin.

(Anti-curl layer)
As described above, in the present invention, an ionizing radiation curable composition containing an ionizing radiation polymerizable compound is used to form a primer layer. However, when the ionizing radiation curable primer layer made of the composition is cured to form the primer layer, there is a problem that the electromagnetic wave shielding member is bent and curled into a ridge having a concave surface on the primer layer side due to curing shrinkage. is there. In addition, when the ionizing radiation curable resin forming the primer layer contains a highly hydrophilic component, if there is a step of passing an aqueous solution such as a plating bath, the resin shrinks after drying and becomes an electromagnetic shielding member. Curling often occurs. If the curl of such an electromagnetic wave shielding member is strong, problems such as wrinkles and unevenness occur in a later process, and problems such as bonding with other members occur in a large panel of a plasma display. Therefore, it is necessary to suppress curling of the electromagnetic wave shielding member.

  The present invention is characterized in that the curl value of the electromagnetic wave shielding member is 20 mm or less by forming an anti-curl layer on the surface of the transparent substrate where the primer layer is not formed, more preferably the curl The value is 10 mm or less. Here, the curl value of the electromagnetic wave shielding member means that the sample of the electromagnetic wave shielding member cut into a square of 100 mm square is dipped in water and dried, and is left to stand with the curled inner surface facing upward on a horizontal table. The average of the four corners (height from the table).

  The anti-curl layer is formed by applying and curing a composition having cure shrinkage. The composition having curing shrinkage can be used without particular limitation as long as it is transparent and has a property of shrinking by curing. As an anti-curl layer, an ionizing radiation curable resin or a thermosetting resin can be used. Can be used. In addition, when using ionizing radiation curable resin, a polymerization initiator may be added as needed, and when using a thermosetting resin, you may add a curing catalyst as needed.

  Examples of the ionizing radiation curable resin include resins obtained by polymerizing monomers and prepolymers exemplified in the description of the primer layer. Specific examples of the thermosetting resin include resins such as polyester-melamine resin, melamine resin, epoxy-melamine resin, phenol resin, polyimide resin, thermosetting acrylic resin, and thermosetting polyurethane resin.

  The thickness of the anti-curl layer can be appropriately determined according to the purpose, but is usually 1 to 100 μm, more preferably 1 to 50 μm. When the thickness of the anti-curl layer is less than 1 μm, it is difficult to obtain an anti-curl effect, and when it exceeds 100 μm, the transparency tends to deteriorate.

  In addition, when the primer layer shrinks due to heat shrinkage or moisture absorption after the primer layer is formed, curling can be prevented by forming an anti-curl layer having the same properties as the primer layer. As described above, since an excellent anti-curl effect can be obtained by forming an anti-curl layer having the same properties as the primer layer, it is preferable to use an ionizing radiation curable composition used for forming the primer layer. Thus, it is preferable to form an anti-curl layer having the same thickness as the primer layer. In addition, when transparency is particularly required, a curl-preventing layer thinner than the primer layer is formed using a composition having a curing shrinkage having a higher shrinkage rate than the ionizing radiation curable composition used for forming the primer layer. It may be formed.

  Further, as will be described later, the formation stage of the anti-curl layer is not particularly limited, and can be appropriately determined according to the purpose. Therefore, the curl prevention layer may be formed on the curled transparent substrate after the primer layer is formed, or the primer layer may be formed on the transparent substrate provided with the curl prevention layer.

Next, the manufacturing method of the electromagnetic wave shielding member of this invention is demonstrated.
(Method for manufacturing electromagnetic shielding member)
The method for producing an electromagnetic wave shielding member of the present invention will be described by dividing it into steps on the primer layer side and the curl prevention layer side of the transparent substrate.

  A typical example of the method for forming the transparent substrate on the primer layer side is as follows. (A) A step of applying an ionizing radiation curable composition for forming a primer layer containing a photopolymerization initiator on a transparent substrate to form an uncured and liquid ionizing radiation curable primer layer; b) A step of applying a conductive paste or a catalyst paste to a plate-like or cylindrical plate surface in which concave portions are formed in a predetermined pattern, scraping off the paste other than the concave portions, and filling the paste into the concave portions of the plate surface (C) The conductive paste or catalyst paste obtained in the step (b) is prepared from the transparent substrate having the ionizing radiation curable primer layer obtained in the step (a). Pressure is applied so as to face the concave side of the plate surface filled with, and then the ionizing radiation curable primer layer is cured by irradiating ultraviolet rays as ionizing radiation to form a primer layer. (D) a step of peeling the transparent substrate and the cured primer layer from the plate surface, and transferring the conductive paste or catalyst paste in the concave portion onto the primer layer; and (e) on the primer layer. A step of curing and / or drying a conductive paste layer or a catalyst paste layer formed in a predetermined pattern transferred to a conductive material layer or a catalyst layer, and (f) a conductive material as required It includes a step of plating the layer to form a metal layer, or a step of plating the catalyst layer to form a metal layer.

The step (a) is a step of forming an ionizing radiation curable primer layer by applying an ionizing radiation curable composition for forming a primer layer on a transparent substrate.
The ionizing radiation curable composition for forming the primer layer used in the step (a) is as described above, and an ionizing radiation polymerizable compound is essential, and particularly when ultraviolet rays or visible rays are used as ionizing radiation, It is a composition containing a photoinitiator.
There is no particular limitation on the method for applying the ionizing radiation curable composition on the transparent substrate, and various coating methods can be used. For example, an appropriate method can be selected from various methods such as gravure coating, comma coating, die coating, and roll coating. Can do.
When the primer layer resin composition contains a solvent, a drying process is performed after coating. However, when the primer layer resin composition is a non-solvent type containing no solvent, the drying process is unnecessary.
It is important that the ionizing radiation curable primer layer formed in this way is in a state of maintaining fluidity at the time of pressure bonding described later.

((B) Process)
This step (b) is a step of filling a plate-like or cylindrical plate surface in which concave portions are formed in a predetermined pattern with a conductive paste or a catalyst paste.
Specifically, after applying a conductive paste or a catalyst paste on a plate-like or cylindrical plate surface in which recesses are formed in a predetermined pattern of mesh or stripe, the conductive material adhered outside the recesses This is a step of scraping off the paste or catalyst paste and filling the conductive paste or catalyst paste into the recesses. This conductive paste or catalyst paste is as described above. The conductive layer forming material adhered to other than the recesses can be scraped off with, for example, a doctor blade.

(Step (c))
In this step (c), the transparent substrate having the ionizing radiation curable primer layer obtained in the step (a) is used as the conductive paste obtained by the ionizing radiation curable primer layer in the step (b). Alternatively, it is a step of forming a primer layer by press-bonding so as to face the concave side of the plate surface filled with the catalyst paste, and then curing the ionizing radiation-curable primer layer by irradiation with ionizing radiation.
In the step (c), first, the ionizing radiation curable primer layer faces the transparent substrate having the ionizing radiation curable primer layer on the concave side of the plate surface filled with the conductive paste or the catalyst paste. Crimp to. This crimping can be performed, for example, with a nip roll provided with a biasing pressure adjusting means. By this crimping operation, the conductive paste or catalyst paste in the recess and the ionizing radiation curable primer layer having fluidity can be brought into close contact with each other without a gap.
Next, the ionizing radiation curable primer layer is cured by irradiating the ionizing radiation curable primer layer from the transparent substrate side to form the primer layer. The dose of ionizing radiation is usually about 10 to 5000 mJ / cm ² , preferably 100 to 500 mJ / cm ² in terms of ionizing radiation.

((D) step)
In the step (d), the ionizing radiation curable primer layer is cured in the step (c) to form a primer layer, and then the transparent substrate and the primer layer which is cured and integrated with the transparent substrate are peeled off from the plate surface. In this step, the conductive paste or catalyst paste in the recess is transferred onto the cured primer layer.
In the step (d), when the transparent substrate is peeled off from the plate surface, the ionizing radiation curable primer layer is cured. Transcribed.

(Step (e))
This step (e) is a step of forming a conductive material layer or catalyst layer by curing and / or drying a conductive paste or catalyst paste formed in a predetermined pattern transferred onto the primer layer.
Although hardening and drying of the said electrically conductive paste or catalyst paste are based on the kind of binder resin, it is normally performed by heat-processing at the temperature of about 50-150 degreeC, Preferably it is 70-120 degreeC.

((F) Process)
In the first aspect of the conductive layer of the electromagnetic wave shielding member of the present invention, if only the conductive material layer formed as described above is insufficient for the desired conductivity, it is necessary to further improve the conductivity. Accordingly, the conductive material layer is plated to form a metal layer (second aspect of the conductive layer of the electromagnetic wave shielding member of the present invention).
As the plating treatment, either electroplating treatment or electroless plating treatment can be used, but as described above, electroplating treatment is preferable. The electroplating process and the electroless plating process are as described above.
In the third aspect of the conductive layer of the electromagnetic wave shielding member of the present invention, the metal layer 4 is formed on the catalyst layer 3 ′ by electroless plating or the like. As described above, since electroless plating takes time for metal deposition, the necessary conductivity may be imparted by electroplating after ensuring the necessary minimum conductivity by electroless plating.
After the plating treatment, it may be wound up as it is after being subjected to other treatments, for example, blackening treatment or rust prevention treatment of the metal layer, or formation of the protective layer, if necessary, or cut to a predetermined size. It may be a sheet.

  The process on the curl prevention layer side of the transparent substrate is as follows. That is, a composition having a curing shrinkage containing a polymerizable monomer and a polymerizable prepolymer so as to have a target thickness may be applied to a transparent substrate and cured.

  The step of forming the anti-curl layer is not particularly limited and can be appropriately determined according to the purpose. For example, before the step (a) (the step of applying an ionizing radiation curable composition for forming a primer layer on a transparent substrate to form an ionizing radiation curable primer layer), the curling of the transparent substrate in advance is prevented. The step (e) (the conductive paste layer or catalyst paste layer formed in a predetermined pattern transferred onto the primer layer is cured to form a conductive material layer or catalyst layer. An anti-curl layer may be formed after the forming step. The method of forming the anti-curl layer before the step (a) is preferable in that the number of manufacturing steps after the formation of the conductive layer is reduced, so that damage to the conductive layer due to impact or the like can be avoided. Further, the method of forming the anti-curl layer after the step (e) is preferable in that an appropriate measure can be made to adjust the curl to a necessary and sufficient level in accordance with the curing shrinkage of the primer layer.

As described above, the electromagnetic wave shielding member of the present invention can be manufactured.
The electromagnetic wave shielding member obtained in this way can be used as an optical filter by providing an optical adjustment layer. As the optical adjustment layer, a conventionally known layer may be used as it is. For example, a layer imparting optical functions such as a near infrared absorption layer, a neon light absorption layer, an ultraviolet absorption layer, an antireflection layer, an antiglare layer, or a hard layer. Examples include layers that provide other functions such as a coat layer, an antifouling layer, and an antistatic layer. By mounting such an electromagnetic wave shielding member or an optical filter having an electromagnetic wave shielding member on the plasma display panel, a plasma display device can be obtained.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.

(Curl evaluation method)
The electromagnetic wave shielding members obtained in Examples and Comparative Examples were cut into 100 mm squares and left standing on a horizontal table with the curled surface facing up. The average value of the floating amount (height from the table) at the four corners of the square at this time was defined as the curl value. The environmental atmosphere at this time was set to a temperature of 23 ° C. and a relative humidity of 50%.

Production Example 1 (Preparation of conductive paste)
After blending 93 parts by mass of flaky silver particles having an average particle diameter of about 2 μm as conductive fine particles, 7 parts by mass of thermoplastic polyester urethane resin as binder resin, and 25 parts by mass of butyl carbitol acetate as solvent, the mixture is sufficiently stirred and mixed. A conductive paste was prepared by kneading with three rolls.

Example 1
First, as a transparent substrate, a long roll-wound polyethylene terephthalate (PET) film having a width of 1000 mm and a thickness of 100 μm subjected to easy adhesion treatment on one side was used. The PET film set in the supply unit was drawn out, and an uncured and liquid ionizing radiation curable composition for the primer layer was applied and formed on the easy adhesion treatment surface so as to have a thickness of 20 μm. The application method employs a normal gravure reverse method, and the ionizing radiation curable composition is 40 parts by weight of epoxy acrylate, 53 parts by weight of a monofunctional monomer (not including a hydrophilic monomer), and 7 parts by weight of a trifunctional monomer. Furthermore, 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184 (Ciba Specialty Chemicals)) 3 parts by mass was added as a photoinitiator. Although the ionizing radiation curable primer layer after application showed fluidity when touched, it did not flow down from the PET film.
Next, the PET film on which the ionizing radiation curable primer layer is formed is subjected to an intaglio roll that performs a transfer process. Prior to that, a grid-like mesh pattern having a line width of 20 μm, a line pitch of 300 μm, and a plate depth of 10 μm is obtained. The conductive paste prepared in Production Example 1 is applied to the plate surface of the intaglio roll formed with the concave portion with a pick-up roll, and the conductive paste other than the concave portion is scraped off with a doctor blade to fill the conductive paste only in the concave portion. I let you. A PET film on which a primer layer is formed is provided between the intaglio roll filled with the conductive paste in the recess and the nip roll, and the ionizing radiation curable by the pressing force (biasing force) of the nip roll against the intaglio roll. The primer layer was caused to flow into the recess above the conductive paste existing in the recess of the intaglio, and the conductive paste and the ionizing radiation curable primer layer were brought into close contact with each other without any gap.

Next, the transfer process performed is as follows. First, a PET film on which an ionizing radiation curable primer layer is formed is sandwiched between an intaglio roll and a nip roll with the primer layer facing the plate surface side of the intaglio roll. Between the intaglio roll and the nip roll, the primer layer of the PET film is pressed against the plate surface. Since the primer layer has fluidity, the primer layer pressed against the plate surface also flows into the recess filled with the conductive paste, and fills the recess of the conductive paste generated in the recess. Thus, the ionizing radiation curable primer layer is in close contact with the conductive paste without any gap. Thereafter, the intaglio roll is further rotated and irradiated with ultraviolet rays by a UV lamp, and the primer layer made of the ionizing radiation curable composition is cured. Due to the curing of the primer layer, the conductive paste in the recesses of the intaglio roll is brought into close contact with the primer layer, and then the film is cured by the nip roll on the outlet side and the primer layer that is bonded and integrated with the film is peeled off from the intaglio roll. A conductive paste is transferred and formed on the primer layer. The transfer film thus obtained was passed through a drying zone at 110 ° C. to evaporate the solvent of the silver paste, thereby forming a conductive material layer having a mesh pattern on the primer layer. The thickness of the conductive material layer at this time (thickness difference between the mesh pattern portion where the conductive material layer is formed and the other portions) is about 9 μm, and the silver paste in the concave portion of the plate has a high transition rate. Had been transferred. Moreover, neither disconnection nor shape defect was seen.
Next, the surface of the transparent substrate on which the conductive material layer and the primer layer are not formed is coated with the ionizing radiation curable composition used for forming the primer layer so as to have a thickness of 10 μm and irradiated with ultraviolet rays. An anti-curl layer was formed to produce an electromagnetic wave shielding member.
The curl value of the obtained electromagnetic wave shielding member was 1 mm.

Comparative Example 1
When the same curl value was measured using the PET film before forming the anti-curl layer in Example 1 (PET film on which the conductive material layer and the primer layer were formed) as a sample, it was 25 mm.

  According to the present invention, an electromagnetic wave shielding pattern can be accurately produced without causing problems such as disconnection of a pattern due to poor transfer, such as a conductive paste, shape failure, and low adhesion, and curling can be suppressed later. An electromagnetic wave shielding member for a plasma display that does not cause problems in the process is provided.

It is a typical top view which shows an example of the electromagnetic wave shielding member of this invention. It is an enlarged view of the A-A 'cross section in FIG. It is typical sectional drawing which expands and shows a part of FIG.

Explanation of symbols

1 Transparent substrate 2 Primer layer 3 Conductive material layer (3 'catalyst layer)
4 Metal layer 5 Anti-curl layer 6 Protective layer 7 Electromagnetic wave shielding pattern 10 Electromagnetic wave shielding member

Claims (9)

An electromagnetic wave shielding member for plasma display having a transparent substrate, a primer layer formed on one surface of the transparent substrate, and a conductive layer formed in a predetermined pattern on the primer layer,
The primer layer is made of a cured product of ionizing radiation curable resin,
Of the primer layer, the thickness of the portion where the conductive layer is formed is larger than the thickness of the portion where the conductive layer is not formed,
A curl of the electromagnetic wave shielding member is formed by forming a layer (anti-curl layer) formed by coating and curing a composition having curing shrinkage on the surface of the transparent substrate on which the primer layer is not formed. An electromagnetic wave shielding member for a plasma display, characterized in that the value is 20 mm or less.   The conductive layer is a conductive material layer composed of conductive fine particles and a binder resin, or a metal layer further formed on the surface of the conductive material layer, or a catalyst composed of an electroless plating catalyst, a carrier and a binder resin. The electromagnetic wave shielding member for a plasma display according to claim 1, wherein the surface of the layer is any one of which a metal layer is formed.   3. The electromagnetic wave shielding member for plasma display according to claim 1, wherein the curling shrinkable composition for forming the anti-curl layer is the same as the ionizing radiation curable composition for forming the primer layer. . A transparent substrate, a primer layer formed on one surface of the transparent substrate, a conductive material layer formed in a predetermined pattern on the primer layer, and a primer layer of the transparent substrate are formed An anti-curl layer formed on a non-curled surface, and the method for producing an electromagnetic wave shielding member according to claim 1,
The forming method on the primer layer side of the transparent substrate is
(A) Applying an uncured liquid ionizing radiation curable composition for forming a primer layer containing a photopolymerization initiator on a transparent substrate to form an ionizing radiation curable primer layer;
(B) a step of filling a conductive paste in a plate-like or cylindrical plate surface in which concave portions are formed in a predetermined pattern;
(C) The transparent substrate having the ionizing radiation curable primer layer obtained in the step (a) is filled with the conductive paste obtained in the step (b). Pressure-bonding so as to face the concave side of the plate surface, and then curing the ionizing radiation-curable primer layer by irradiation with ionizing radiation to form a primer layer;
(D) peeling off the transparent substrate and the cured primer layer from the plate surface, and transferring the conductive paste in the recesses onto the primer layer;
(E) including a step of curing and / or drying a conductive paste layer formed in a predetermined pattern transferred onto the primer layer to form a conductive material layer;
The method of forming the anti-curl layer is
The manufacturing method of the electromagnetic wave shielding member for plasma displays characterized by including the process of applying the composition which has hardening shrinkage | contraction property to a transparent base-material surface, and making it harden | cure. In addition to the process of Claim 4, the manufacturing method of the electromagnetic wave shielding member for plasma displays characterized by including the process of forming a metal layer by further plating (f) a conductive material layer. A transparent substrate, a primer layer formed on one surface of the transparent substrate, a catalyst layer formed in a predetermined pattern on the primer layer, a metal layer formed on the surface of the catalyst layer, An anti-curl layer formed on a surface of the transparent substrate on which no primer layer is formed, and the method for producing an electromagnetic wave shielding member for plasma display according to any one of claims 1 to 3,
The forming method on the primer layer side of the transparent substrate is
(A ′) applying an uncured liquid ionizing radiation curable composition for primer layer formation containing a photopolymerization initiator on a transparent substrate to form an ionizing radiation curable primer layer;
(B ′) a step of filling a catalyst paste with a plate-like or cylindrical plate surface in which recesses are formed in a predetermined pattern;
(C ′) The transparent substrate having the ionizing radiation curable primer layer obtained in the step (a ′) is filled with the catalyst paste obtained in the step (b ′). Pressure-bonding so as to face the concave side of the plate surface formed, and then curing the ionizing radiation-curable primer layer by irradiation with ionizing radiation to form a primer layer;
(D ′) peeling off the transparent substrate and the cured primer layer from the plate surface, and transferring the catalyst paste in the recesses onto the primer layer;
(E ′) a step of curing and / or drying a catalyst paste layer formed in a predetermined pattern transferred onto the primer layer to form a catalyst layer;
(F ′) including a step of plating the catalyst layer to form a metal layer;
The method of forming the anti-curl layer is
The manufacturing method of the electromagnetic wave shielding member for plasma displays characterized by including the process of applying the composition which has hardening shrinkage | contraction property to a transparent base-material surface, and making it harden | cure. The process of applying and curing a composition having curing shrinkage on the transparent substrate surface,
The method for producing an electromagnetic wave shielding member for plasma display according to any one of claims 4 to 6, wherein the method is before the step of forming an ionizing radiation curable primer layer on a transparent substrate. The process of applying and curing a composition having curing shrinkage on the transparent substrate surface,
The method for producing an electromagnetic wave shielding member for plasma display according to any one of claims 4 to 6, wherein the primer layer is formed on the transparent substrate.   The electromagnetic wave shielding member for plasma displays manufactured by the method in any one of Claims 4-8.

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