JPH1072676A - Electromagnetic wave shielding material and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electromagnetic wave shielding material which acts to shield electromagnetic waves and allows seeing-through of the inside when the material is installed to the front surface, etc., of a display device. SOLUTION: This process for producing the see-through electromagnetic wave shielding material consists in applying a resin soln. contg. a reducing metal onto a transparent base material, drying the coating to form a coating film, then subjecting the coating to a reduction treatment at need, forming an electroless plating layer over the entire surface of the coating film and, simultaneously, making the coating film black, forming the resist parts of desired patterns on the electroless plating layer and removing the electroless plating layer of the non-resist parts and the black parts in the coating film under the electroless plating layer by etching. The salt or complex of the metal or reduce particles are used as the reducing metal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a transparent electromagnetic wave shielding material which is installed on the front of a display device or the like to shield electromagnetic waves.

[0002]

2. Description of the Related Art In addition to excellent electromagnetic wave shielding performance, an electromagnetic wave shielding material installed on the front of a display device, etc.
It is required to have excellent transparency and a wide viewing angle.
Japanese Unexamined Patent Publication No. 5-1 is an electromagnetic wave shielding material satisfying this requirement.
The invention described in No. 6281 is known. That is, the present invention provides a method of coating cellulose acetate propionate on a transparent acrylic plate and laminating a hydrophilic transparent resin layer. After forming a plating nucleus, washing with water, performing electroless copper plating, then etching by a resist method using ferric chloride to pattern the electroless plating layer. The hydrophilic transparent resin layer under the patterned electroless plating layer becomes a black pattern portion. "

[0003]

However, the invention disclosed in Japanese Patent Application Laid-Open No. Hei 5-16281 discloses an electroless plating nucleus (catalyst) which is immersed in a palladium hydrochloride-acid colloidal catalyst solution before the electroless plating step, and is immersed in a hydrophilic transparent resin. Had to be formed.

[0004] However, this method has a problem that the plating cost increases because the electroless plating nuclei are adsorbed on both surfaces of the substrate and are plated on both surfaces. Further, in order to plate only the surface on which the coating film is formed, a plating prevention treatment is required on the opposite surface, which causes a problem that the number of steps increases and the manufacturing cost increases. In addition, when the substrate is immersed in the catalyst solution, there is a problem that the coating film adhesion is significantly reduced.

Furthermore, since the catalyst is penetrated into the coating film by immersing the substrate in the catalyst solution, it is difficult to make the distribution of the catalyst uniform in the thickness direction of the coating film, and the blackening of the coating film by plating is stable. And it was difficult to perform it efficiently. Furthermore,
There is a problem in that the plating adhesion varies, and defects are likely to occur when patterning the plating layer, resulting in poor yield.

[0006]

According to the present invention, there is provided (1) a method in which a resin solution containing a reducing metal is applied to a transparent substrate, dried to form a coating film, and then subjected to a reduction treatment if necessary. Forming an electroless plating layer on the entire surface of the coating film and simultaneously blackening the coating film, forming a resist portion of a desired pattern on the electroless plating layer, and forming an electroless plating layer of the non-resist portion and the electroless plating. A method for producing a see-through electromagnetic shielding material, wherein a black portion in a coating film under a layer is removed by etching; (2) the reducing metal is a metal salt or complex, or reduced metal particles (1) The described method. (3) A metal salt or complex [A] in which the reducing metal can be reduced only catalytically with a reducing agent and a metal salt or complex [B] directly reducible with a reducing agent, or can be reduced only catalytically with a reducing agent The method according to (1), which is a metal salt or complex [A] and reduced metal particles [C]. (4) A resin solution in which reduced metal particles are dispersed is applied to a transparent base material, dried to form a coating film, and then, if necessary, activated, and then an electroless plating layer is formed on the entire surface of the coating film. The coating film is blackened, a resist portion having a desired pattern is formed on the electroless plating layer, and the black portion in the coating film under the electroless plating layer and the electroless plating layer in the non-resist portion is removed by etching. The method according to (2), wherein (5) On a transparent substrate, a metal salt or complex [A] that can only be reduced catalytically with a reducing agent and a metal salt or complex [B] that can be directly reduced with a reducing agent, or only a catalytic reduction with a reducing agent A coating solution is formed by applying and drying a resin solution in which a possible metal salt or complex [A] and reduced metal particles [C] are dissolved or dispersed, and then subjected to a reduction treatment. Simultaneously with the formation of the plating layer, the coating film is blackened, a resist portion having a desired pattern is formed on the electroless plating layer, and the black portion of the electroless plating layer in the non-resist portion and the coating film below the electroless plating layer is formed. The method according to (3), wherein the portion is removed by etching. (6) The metal salt or complex is a group Ib of the periodic table of the elements,
Or the method according to (3) or (5), which is a salt or complex of a metal belonging to Group VIII. (7) The reduced metal particles according to (2) or (4), wherein the reduced metal particles are reduced metal colloid particles of a metal belonging to Group Ib or Group VIII of the periodic table of elements, or reduced metal powder obtained from the dispersion. Method. (8) A metal salt or complex that can be reduced only catalytically with a reducing agent [A] is a metal salt or complex belonging to Group 4b of Group Ib or Group VIII of Periodic Table. And a directly reducible metal salt or complex [B]
A reduced metal colloid of a metal belonging to Group Ib or Group VIII, which is a salt or complex of a metal belonging to Group b, Group 5 or 6 or Group VIII belonging to Group 5 or 6; The method according to (5), wherein the particles are particles or reduced metal powder obtained from the dispersion. (9) The method according to (1), (4), or (5), wherein the resin of the resin solution is polyvinyl acetal. (10) The method according to (3), (5) or (8), wherein the reducing agent is a compound capable of reducing [A] only catalytically and directly reducing [B]. (11) (1), (4), (5), wherein the coating film contains 1 to 200 mg / m ² (weight per unit area of the coating film) of Pd in the reduced metal in terms of PdCl _2. ,
The method according to (8) or (10). (12) The transparent substrate is any of a glass plate or a plastic film, sheet or plate (1), (4),
(5) The method according to (8) or (10). (13) The electromagnetic wave shielding material has a light transmittance of 65% or more,
Shielding performance at 30 to 1000 MHz is 40 to 8
(1), (4), (5), (8) or (1)
0) A method as described above. (14) The degree of blackening of the coating film viewed from the transparent substrate side is 2.9 to 4. in terms of optical density (when the incident angle is 7 ° and specular reflection is not included).
0, which is a transparent electromagnetic wave shielding material.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The substrate of the present invention is selected depending on the application and is required to be transparent, and examples thereof include a glass plate, a plastic film, a plastic sheet, and a plastic plate. Also, the shape of the substrate is not particularly limited.

[0008] As the plastic used for the substrate, a resin having high transparency is preferable. Acrylic resin, polycarbonate, polyethylene, AS resin, vinyl acetate resin, polystyrene, polypropylene, polyester, polysulfone, polyethersulfone, polyvinyl chloride Suitable are olefin / maleimide copolymers, norbornene-based resins, etc. Among them, olefin / maleimide copolymers and norbornene-based resins having high heat resistance are preferred.

The heat distortion temperature of plastic is 140-3
60 ° C., coefficient of thermal expansion is 6.2 × 10^-Fivecm / cm ・ ℃
Hereinafter, the pencil hardness is 2H or more, and the bending strength is 1,200 to
2,000kgf / cm^Two , Flexural modulus is 30,000
~ 50,000kgf / cm^Two , Tensile strength is 700 ~
1,200kgf / cm^Two It is preferred that this
Such plastics are less likely to warp even at high temperatures,
Difficult to use in a wide range of environments.

The light transmittance of plastic is 90% or less.
Above number is 50-70, photoelastic constant (glass area)
The absolute value of is 10 × 10^-13 cm^Two / Dyne or less
Is preferred. Such plastics are highly transparent
(Bright), low birefringence (hard to form double images)
Therefore, the original image quality and brightness of the display are not impaired.
No.

The resin in the resin solution to be applied to the base material is not limited to transparency, and may be of any type as long as it has good solubility or dispersibility in metal salts or complexes, or reduced metal particles. .

As the resin to be used, a hydrophilic transparent resin is preferable because the plating solution permeates into the resin, the reduced metal (plating catalyst) reacts as a nucleus, and the plated metal precipitates and turns black. As the hydrophilic transparent resin layer, a vinyl acetal resin, a vinyl alcohol resin, an acrylic resin, a cellulose resin, and the like are suitable, and among them, a vinyl acetal resin such as polyvinyl butyral, and a cellulose acetate butyrate are preferable. Cellulosic resins are preferred.

The reducing metal used in the present invention is a metal salt or complex, or a reduced metal particle, and the metal salt or complex can be easily reduced to a metal by a reducing agent described below. Organic or inorganic, especially inorganic metal salts that are soluble in the common solvent with are preferred. Specific examples include sulfates, nitrates, chlorides, organic salts (eg, acetates) of metals belonging to Group Ib and Group VIII of the Periodic Table of the Elements, such as iron, copper, nickel, cobalt, and palladium. Nitrile complex, acetylacetonato complex,
Ammonia complexes and the like can be mentioned.

The reduced metal particles are colloidal particles in a reduced metal colloidal dispersion or reduced metal powders obtained from the dispersion, have catalytic activity for plating, and can be uniformly dispersed in a coating film. The type and particle size of the metal are not limited as long as it is used. Desirably, such reduced metal particles are stable to the atmosphere or moisture. As a specific example,
Colloidal particles containing a Group VIII metal (Ni, Co, Rh, Pd, etc.), and reduced Pd colloid particles or reduced Pd powder obtained therefrom are particularly preferred. The reduced metal colloid particles can be produced by the method described in JP-A-1-315334. That is, a colloidal dispersion is obtained by reducing a metal salt in a mixed solution comprising a lower alcohol and an aprotic polar compound.

A metal salt or complex [A] (hereinafter referred to as [A]) which can be reduced only catalytically with a reducing agent and a metal salt or complex [B] (hereinafter [B]) which can be directly reduced.
That. ) Or [A] and reduced metal particles [C]
In the case of (hereinafter referred to as [C]), specific examples of [A] include the fourth period of Group Ib or the fourth period of Group VIII of the periodic table of elements such as iron, cobalt, nickel, and copper. It is a salt or complex of a belonging metal, and examples thereof include a sulfate, a nitrate, a chloride, an organic salt, a benzonitrile complex, an acetylacetonato complex, and an ammonia complex.

[0016] The meaning that the catalyst can be reduced only catalytically with a reducing agent means that a catalyst is required for the reduction, and the reduced metal or the reduced metal particles [C] formed by the reduction [B] described below is the reduction catalyst. become. Therefore, [A] becomes [B] or [C]
It is preferable to be subjected to reduction in combination with.

The directly reducible metal of [B] means that no catalyst is required for the reduction, and for example, rhodium, palladium, silver, platinum, gold, etc., elements 5 and 6 of group Ib of the periodic table of the element. It is a salt or complex of a metal belonging to the fifth cycle or the fifth or sixth cycle of Group VIII.

[C] can be the same as the above-mentioned reduced metal particles.

Salts or complexes of these metals, reduced metal particles,
When [A], [B], and [C] are used alone, or when they are mixed as in [A] and [B], or when they are mixed as in [A] and [C], the range of the total amount is 0.1. 5-100 PHR
(Parts by weight based on 100 parts by weight of resin), and more preferably in the range of 1 to 50 PHR.

If it is less than 0.5 PHR, the plating density and gloss are poor, and if it exceeds 100 PHR, the physical properties of the coating film deteriorate.

Although the mechanism for achieving the effect of the present invention is not clear, when [A] is directly reduced using a strong reducing agent, reduced metal particles of [A] and [B] or [C] are mixed. Whereas in the case of the present invention, [B],
[A] is reduced by these catalysis in the presence of the reduced metal particles of [C], so that the reduced metal of [A] wraps around the reduced metal particles of [B] or [C]. It seems that it is in a state.

As a result, the particle diameter becomes relatively large, and the adhesion of the plating is improved by the anchor effect.

The particle diameter can be controlled by changing the ratio of [A] / [B] and [A] / [C].

In the above [A] / [B] and [A] / [C], if the amount of [A] is small, it is against the object of the present invention to enable the use of [A] of the present invention. When B] and [C] decrease, the reduction catalyst of [A] decreases, and the effective utilization of [A] becomes insufficient.

The solvent for forming the resin solution of the present invention is not particularly limited as long as it can dissolve or mix the resin or metal salt or complex, [A], [B] or the reduced metal particles [C].

For example, single or mixed solvents such as methanol, ethanol, chloroform, methylene chloride, trichloroethylene, tetrachloroethylene, benzene, toluene, xylene, acetone, ethyl acetate, dimethylformamide, dimethylsulfoxide, dimethylacetamide, and N-methylpyrrolidone are preferred. Used.

The appropriate selection is made according to the combination of the resin used and the metal salt or complex or the reduced metal particles.

The amount of the solvent to be used is selected so as to have an appropriate viscosity and fluidity and to be suitable for coating on a substrate.

A solution comprising a resin and a metal salt or complex or reduced metal particles is applied to a substrate having an arbitrary shape and dried to form a coating film containing a metal salt or complex or reduced metal particles. Application is brush coating, spray coating, dip coating, roll coating, calendar coating,
An ordinary coating method such as spin coating or bar coating is selected according to the shape of the substrate.

The conditions (temperature, time, etc.) for forming the coating film are determined according to the type, concentration, thickness of the coating film and the like of the resin.
Usually, it is applied at a nonvolatile content of 0.05 to 20 wt%. The coating thickness is 0.2 to 10μ, preferably 0.5 to 5μ
And

The reduction treatment is usually performed after the final curing, but may be performed during the curing. By treating with a reducing agent, a metal salt or complex in the coating film precipitates as a reducing metal inside or on the surface of the coating film, and this serves as a plating catalyst. The one deposited on the surface is partially protruded from the surface, and an integrated reduced metal plating catalyst layer partially embedded in the coating film is formed.

Therefore, due to the catalytic effect and the anchor effect of the projecting portion, the plating adhesion is extremely good, and there is no need to perform etching (surface roughening).

Examples of the reducing agent for reducing the metal salt or complex include sodium borohydride, lithium borohydride,
In addition to borohydride compounds such as aminoborane and dimethylamine borane, ferrous salts such as FeSO ₄ , hydrogen phosphate metal salts such as sodium hypophosphite, hydroxylamine sulfate, hydrosulfite, and formalin can also be used. Usually, the former borohydride is preferred.

[A] and [B], or [A] and [C]
In this case, the reducing agent is preferably a compound capable of directly reducing [B] and catalytically reducing [A].

For example, sodium hypophosphite, dimethylaminoborane, formalin and the like can be preferably used.

These reducing agents are usually used as an aqueous solution, but may be an organic solvent as long as it can dissolve or disperse the reducing agent, and is not limited. The concentration of the reducing agent in the reducing agent solution is usually 0.05 to 50% by weight, preferably 0.1 to 25% by weight.

This reduction can be easily carried out by immersing a substrate having a coating film containing a metal salt or complex or reduced metal particles in a reducing solution for an appropriate time or spraying the reducing solution.

The reduction temperature is preferably about 10 to 90 ° C., and the contact time with the reducing solution is suitably several tens seconds to about 30 minutes.

The solvent in the coating film may be completely removed by heating before reduction, or may partially remain. In some cases, the residual agent facilitates the penetration of the reducing agent into the coating film.

In the case of a coating film from which the solvent has been completely removed, the temperature of the reducing solution is raised, the coating film is preheated before reduction, the coating film is treated with a swellable solution, and the resin solution has an affinity. The reduction efficiency can be increased by a method such as using a similar solution-based reducing solution having good properties.

The reduction is usually performed until at least the metal salt or complex present in the surface layer is reduced, but may be stopped when the amount of catalyst for plating can be secured.

When the reduced metal particles are used alone, they may be treated with a reducing agent, or treated with an acid or alkali for the purpose of eliminating unevenness in the catalytic activity on the surface and improving the degree of catalytic activity. Good.

In a preferred embodiment of the present invention, for example, the amount of Pd in the reduced metal in the coating film is 1 to 1 in terms of PdCl ₂ .
The content is preferably 200 mg / m ² (weight per unit area of the coating film). If it is less than 1 mg / m ² , it is difficult to obtain a sufficient black color, and if it exceeds 200 mg / m ^2, it is not economical.

The substrate to be plated (catalyst) is transferred to an electroless plating step to obtain a desired metal plating. The electroless plating may be selected according to the purpose by a commonly used method, and typical examples thereof include Ni plating and Cu plating.

In the method of the present invention, by appropriately selecting the kind of the resin and the salt or complex of the metal and / or the reduced metal particles to be used, and changing the operating conditions such as the curing and the treatment conditions with the reducing agent. Thereby, the adhesion, hardness, strength, plating catalytic activity and the like of the obtained plating base coat can be adjusted according to the purpose.

Next, the plating base coat is treated with an electroless plating solution to form an electroless plating layer. The coating film turns black simultaneously with the formation of the electroless plating layer. When viewed from the transparent substrate side, the portion where the electroless plating layer is laminated appears black.

The transparent base material of the transparent electromagnetic wave shielding material (thickness 2 mm, refractive index 1.49, light transmittance 93%, average roughness R
The degree of blackening of the coating film viewed from the a40 °) side is preferably 2.9 or more in terms of optical density (when the incident angle is 7 ° and the specular reflection is not included). If the optical density is less than 2.9, the degree of blackening of the coating film is low and the visibility is poor (the lower the optical density, the stronger the plating gloss and dazzling). When the optical density is 2.9 or more, the degree of blackening of the coating film is sufficiently high and the visibility is good (clearly visible). If it exceeds 4.0, the visibility will not substantially improve with the naked eye.

Next, a resist portion having the same pattern as that of the conductive portion of the electromagnetic wave shielding material is formed on the electroless plating layer. The resist portion may be formed by a generally known method such as a printing method and a photolithography method.

Next, the unnecessary electroless plating layer in the non-resist part and the unnecessary black part are removed by processing with an etchant.

As a result, a black portion having the same pattern is formed under the patterned electroless plating layer in the coating film. Further, the portion from which the electroless plating layer and the black color have been removed has transparency. Thereafter, the resist portion is removed by dipping or spraying in a stripper such as an aqueous alkaline solution that dissolves the resist film.

Thus, a see-through electromagnetic wave shielding material having a conductive portion formed in a desired pattern can be manufactured.

The light transmittance of the transparent electromagnetic wave shielding material is 65.
%, And the shielding performance at 30 to 1,000 MHz is preferably 40 dB or more. Light transmittance of 65
%, It is not practical level when the shielding performance is less than 40 dB.

The etching solution is appropriately selected depending on the type of metal of the electroless plating layer. For example, if the metal of the electroless plating layer is nickel or copper, ferric chloride or the like may be used as an etching solution.

The pattern of the conductive portion of the electromagnetic wave shielding material may be formed by another method without depending on the etching process. For example, a plating catalyst-containing resin coating film may be formed only on a portion where a conductive portion pattern is to be formed on the base material, and may be subjected to electroless plating. This method is economically advantageous because it not only saves the etching process but also saves the coating resin and the plating catalyst.

Next, the present invention will be specifically described with reference to Examples and Comparative Examples.

[0056]

Example 1 Alcohol solution of polyvinyl butyral (PVB) "Denka Butyral # 6000-C" manufactured by Denki Kagaku Kogyo Co., Ltd. and aqueous palladium (Pd) colloid catalyst solution "OPC-80 Catalyst" manufactured by Okuno Pharmaceutical Co. M "as a coating solution (coating solution composition: PVB / catalyst solution / methanol / butanol = 10/43/647/3)
00, Pd colloid 3PHR (PdCl ₂ conversion)).

This coating solution was applied to an A4 size acrylic plate by a bar coating method, air-dried, and then dried at 80 ° C. for 1 hour (coating thickness: 1 μm).

The formed product of the coating film (containing a catalyst) was directly applied to a copper plating solution containing formalin “OPC-
700M "(25 ° C) for 1 hour. As a result,
The surface of the coating film on the acrylic plate had a copper luster, and the back surface of the coating film (observed from the acrylic plate side) was dark black.

For this copper plated product, a positive type photoresist for etching “PMER” manufactured by Tokyo Ohka Kogyo Co., Ltd.
P-DF40S "was applied, prebaked (coating thickness: 5 μm), exposed (using a lattice pattern mask), and developed under the manufacturer's recommended conditions to form a lattice resist pattern.

This resist pattern-formed product was immersed in an etching solution (20% ferric chloride / 1.75% hydrochloric acid aqueous solution) to remove the copper plating film and the black copper in the coating by etching, and became unnecessary. The resist was peeled off to form a conductive pattern (electromagnetic shielding material).

This electromagnetic wave shielding material has a shielding performance of 40 to 80 dB (30 to 1000 MHz), a transparency of 75%, a light transmittance of 75%, other visibility, and a coating film (/
Substrate) adhesion, plating (/ coating) adhesion, and substrate flatness were all good.

[0062]

Example 2 Example 1 except that the coating thickness was 0.75 μm.
Was performed in the same manner as described above.

[0063]

Example 3 The same operation as in Example 1 was carried out except that the thickness of the coating film was changed to 0.5 μm.

[0064]

Example 4 Example 1 except that the coating thickness was 0.25 μm.
Was performed in the same manner as described above.

[0065]

Example 5 In the coating solution of Example 1, Pd colloid 1PHR / copper sulfate 14 was used instead of Pd colloid 3PHR.
A coating solution was prepared using PHR.

Using this coating solution, an electromagnetic wave shielding material was produced in the same manner and under the same conditions as in Example 1.

This electromagnetic wave shielding material exhibited good performance in the same manner as in Example 1. In particular, in terms of the degree of blackening of the coating film,
It was superior to Example 1.

[0068]

Example 6 A coating solution was prepared in the same manner as in the coating solution of Example 1, except that 15 PHR of copper chloride was used instead of 3 PHR of the Pd colloid.

Using this coating solution, a coating film was formed in the same manner and under the same conditions as in Example 1 (coating thickness: 1 μm).

This coated film-formed product was immersed (reduced) in a 0.5% aqueous solution of sodium borohydride for 10 minutes.
Copper plating and an electromagnetic wave shielding material were produced in the same manner and under the same conditions.

This electromagnetic wave shielding material showed good performance in the same manner as in Example 1.

[0072]

Example 7 In the coating solution of Example 1, palladium acetylacetonate 5 was used instead of Pd colloid 3PHR.
A coating solution was prepared using PHR.

After a coating film (thickness: 3 μm) was formed with this coating solution, 15% aqueous solution of sodium hypophosphite (50 ° C.) was added.
After being immersed (reduced) for a minute, an electromagnetic wave shielding material was produced in the same manner and under the same conditions as in Example 1 after plating.

This electromagnetic wave shielding material showed good performance in the same manner as in Example 1.

[0075]

Example 8 A coating solution was prepared by using 1 PHR of palladium acetate / 24 PHR of nickel acetate instead of 3 PHR of Pd colloid in the coating solution of Example 1.

After forming a coating film (film thickness: 5 μm) with this coating solution, 1% dimethylamine borane aqueous solution (40 ° C.) was added.
After being immersed (reduced) for 0 minutes, an electromagnetic wave shielding material was produced by the same method and conditions as in Example 1 after plating.

This electromagnetic wave shielding material showed good performance in the same manner as in Example 1. In particular, it was superior to Example 1 in the point of the degree of blackening of the coating film.

[0078]

Example 9 A coating solution was prepared by using cellulose acetate butyrate “CAB 553-0.4” manufactured by Eastman Kodak Co. in place of PVB in the coating solution of Example 1.

Using this coating solution, an electromagnetic wave shielding material was produced in the same manner and under the same conditions as in Example 1.

This electromagnetic wave shielding material exhibited good performance in the same manner as in Example 1. In particular, it was superior to Example 1 in terms of transparency.

[0081]

Example 10 Instead of the acrylic plate of Example 1, a transparent base material of olefin / maleimide copolymer "TI-160" manufactured by Tosoh Corporation or a norbornene resin "ARTON" manufactured by Nippon Synthetic Rubber Co., Ltd. was used as the transparent substrate. An electromagnetic wave shielding material was manufactured using a heat-resistant plastic substrate.

These electromagnetic wave shielding materials exhibited good performances, similarly to the first embodiment. In particular, the flatness of the substrate was superior to that of Example 1 (the warpage was clearly smaller than that of the substrate having the same thickness and area).

More specifically, when a plastic substrate having a poor heat resistance and rigidity is generally warped due to the heat generated by the display when it is disposed on the front surface of the (plasma) display and used as an electromagnetic wave shielding material, the display is generally warped. However, these problems were not observed at all.

[0084]

Example 11 An electromagnetic wave shielding material was produced using the PET film instead of the acrylic plate on the transparent substrate of Example 1.

This electromagnetic wave shielding material showed good performance in the same manner as in Example 1. Further, even when the substrate (PET film) was bent, peeling between the substrate and the coating film and between the coating film and the plating was not observed, and the film was highly followable.

[0086]

Embodiment 12 In the plating solution of Example 1, a silver plating solution (20 ° C.) was used instead of the copper plating solution, and a 3% nitric acid aqueous solution was used in the etching solution instead of the ferric chloride / hydrochloric acid aqueous solution. Then, an electromagnetic wave shielding material was produced.

Composition of silver plating solution (silver solution) Silver nitrate 3.5 g Ammonia water Until sedimentation is redissolved Water 60 ml Sodium hydroxide 2.5 g / 60 ml Water (reducing solution) Glucose 45 g Tartaric acid 4 g Alcohol 100 ml Water 1000 ml This electromagnetic wave shielding material Showed good performance in the same manner as in Example 1. In particular, it was superior to Example 1 in terms of electromagnetic wave shielding performance.

[0088]

Comparative Example 1 A coating solution was prepared from the coating solution of Example 1 by using water instead of the catalyst solution (coating solution composition; PV
B / water / methanol / butanol = 10/43/647
/ 300).

Using this coating liquid, a coating film was formed in the same manner and under the same conditions as in Example 1 (coating thickness: 1 μm).

This coated film-formed product was immersed in the same catalyst solution (25 ° C.) as in Example 1 for 15 minutes (the coated film after immersion (catalyst adsorption) was the same as the coated film of Example 1 (containing catalyst). The degree of coloring was high).

Example 1
As a result of performing copper plating under the same method and conditions as above, copper plating was precipitated from both surfaces (the copper plating film on the surface without a coating film was
When the deposition of copper plating progressed and the plating thickness increased, most of the coating peeled off).

The interface between the plated layer and the coating film after plating (observed from the acrylic plate side) exhibited a copper luster. In addition, swelling and peeling of the coating film occurred during copper plating (the plated product was not worthy of forming a conductive pattern).

[0093]

Comparative Example 2 The same procedure as in Comparative Example 1 was carried out except that the immersion time for applying the catalyst was changed to 30 minutes.

[0094]

Comparative Example 3 The same procedure as in Comparative Example 1 was carried out except that the immersion time for applying the catalyst was changed to 45 minutes.

[0095]

Comparative Example 4 The same procedure as in Comparative Example 1 was carried out except that the immersion time for applying the catalyst was changed to 60 minutes.

Tables 1 and 2 show the results of comparison between Examples 1 to 12 and Comparative Examples 1 to 4. It can be seen from Tables 1 and 2 that the method of the present invention can be efficiently blackened with a thin coating layer and a small amount of reduced metal (catalyst).

[0097]

[Table 1]

[0098]

[Table 2]

[0099]

[Table 3]

[0100]

The present invention has the following effects. There are few restrictions on pattern design. Easy connection with earth lead wire. High conductivity and high shielding effect. Transparent substrate side is black and visibility is good. No need for black coating.

Furthermore, the production cost is low because the step of forming the coating film and providing the catalyst (activation) is only one step of forming the coating film containing the catalyst. One-side plating is possible only by forming the catalyst-containing coating film on one side, and the plating cost is low. Since the step of providing a catalyst (with a decrease in coating film adhesion) is omitted, it is easy to ensure coating film adhesion. Since the catalyst is uniformly distributed in the coating film, plating is reliably deposited from the inside of the coating film, and blackening can be efficiently performed with a small amount of catalyst (the catalyst cost is low). In addition, since the coating film and the plated metal are integrated with each other, the plating adhesion is high.

(10) [A] / [B] or [A] /
When used in the combination of [C], the use of a reducing agent that can only reduce [A] catalytically (can directly reduce [B]) allows the reduction metal particles of [B] or [C] to be reduced. The surroundings can be in a state surrounded by the reduced metal of [A],
Therefore, if the ratio of [A] / [B], [A] / [C] is changed, the particle size can be controlled, and the efficiency can be improved more efficiently than when [A], [B], and [C] are used alone. The coating can be blackened. Further, plating adhesion can be stably ensured.

As described above, the effect of the present invention is remarkable.

Claims (14)

[Claims] 1. A resin solution containing a reducing metal is applied on a transparent substrate, dried to form a coating film, and if necessary, subjected to a reduction treatment, then an electroless plating layer is formed on the entire surface of the coating film. Simultaneously with the formation, the coating film is blackened, a resist portion of a desired pattern is formed on the electroless plating layer, and the black portion in the electroless plating layer of the non-resist portion and the coating film under the electroless plating layer is etched. A method for producing a see-through electromagnetic wave shielding material, comprising: 2. The method according to claim 1, wherein the reducing metal is a metal salt or complex, or reduced metal particles. 3. A metal salt or complex [A] in which a reducing metal can be reduced only catalytically with a reducing agent and a metal salt or complex [B] directly reducible with a reducing agent, or reduced only catalytically with a reducing agent The method according to claim 1, wherein the metal salt or complex [A] and the reduced metal particles [C] are possible. 4. A coating solution is formed by applying a resin solution in which reduced metal particles are dispersed on a transparent base material, followed by drying to form a coating film. Then, if necessary, an electroless plating layer is formed on the entire coating film. At the same time, the coating is blackened, a resist portion having a desired pattern is formed on the electroless plating layer, and the black portion of the electroless plating layer of the non-resist portion and the coating under the electroless plating layer is etched. 3. The method of claim 2, wherein said removing is performed. 5. A metal salt or complex [A] that can be reduced only catalytically with a reducing agent and a metal salt or complex [B] that can be directly reduced with a reducing agent, or a transparent substrate. A resin solution in which a metal salt or complex [A] reducible only to the metal and the reduced metal particles [C] are dissolved or dispersed, applied and dried to form a coating film, and then subjected to a reduction treatment, and then the entire coating film is coated. At the same time as forming an electroless plating layer, the coating film is blackened, a resist portion having a desired pattern is formed on the electroless plating layer, and the electroless plating layer of the non-resist portion and the coating film under the electroless plating layer are formed. 4. The method according to claim 3, wherein the black portion inside is removed by etching. 6. The method according to claim 3, wherein the metal salt or complex is a metal salt or complex belonging to Group Ib or Group VIII of the Periodic Table of the Elements. 7. The reduced metal particles are selected from the group Ib of the periodic table of elements.
The method according to claim 2 or 4, wherein the metal is a colloidal particle of a metal belonging to Group III or Group VIII, or a reduced metal powder obtained from the dispersion. 8. A metal salt or complex [A] which can be reduced only catalytically with a reducing agent is a metal salt or complex [A] of Group Ib of the Periodic Table of the Elements.
A salt or complex of a metal belonging to the fourth cycle of Group VIII or Group VIII, wherein the directly reducible metal salt or complex [B] is a fifth or sixth cycle of Group Ib or a fifth or sixth group of Group VIII. The reduced metal particle [C] is a reduced metal colloid particle of a metal belonging to Group Ib or Group VIII, or a reduced metal powder obtained from the dispersion, which is a salt or complex of a metal belonging to the periodicity. 5. The method according to 5. 9. The method according to claim 1, wherein the resin of the resin solution is polyvinyl acetal. 10. The reducing agent is a compound capable of reducing [A] only catalytically and directly reducing [B].
Or the method of 8. 11. The amount of Pd in the reduced metal in the coating film is determined by PdC
Claim 1,4,5,8 or 10 The method according to, characterized in that l ₂ converted at 1 to 200 mg / m ² (weight per coating unit area) containing. 12. The method according to claim 1, wherein the transparent substrate is a glass plate or a plastic film, sheet or plate. 13. The method according to claim 1, wherein the transparent electromagnetic wave shielding material has a light transmittance of 65% or more and a shielding performance at 30 to 1000 MHz of 40 to 80 dB. 14. The degree of blackening of the coating film as viewed from the transparent substrate side,
1. Optical density (when the incident angle is 7 ° and specular reflection is not included)
A transparent electromagnetic wave shielding material having a thickness of 9 to 4.0.