JP2003318595A - Electromagnetic wave shielding material and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic wave shielding material having a highly durable conductive layer without rusting and preventing glare in appearance, and a method for producing the same. SOLUTION: An electromagnetic wave shielding material 5 is composed of two layers of a conductive metal film 2 and a printed film 3 of an ionizing radiation-curable ink in which a black pigment is dispersed on the surface of a transparent base material 1; The shield pattern 4 includes a thin line such as a geometric pattern. This electromagnetic wave shielding material 5 forms a conductive metal film 2 on the surface of a transparent base material 1 and uses an ionizing radiation-curable ink containing a black pigment on the surface of the metal film, and prints grids, stripes, honeycomb patterns, A printed film 3 having a pattern consisting of fine lines such as a geometric pattern is formed, and a portion of the conductive metal film 2 which is not covered with the printed film 3 is removed by an etching process. Shield pattern 4 consisting of film 2
Is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic wave shielding material having a high light-transmitting property and an electromagnetic wave shielding property such as a window frame and an optical filter of a PDP television, and a manufacturing method thereof.

[0002]

2. Description of the Related Art In recent years, various reports have been made on the effects of electromagnetic waves emitted from electrical equipment on the human body.
Accompanying this, there is increasing interest in technology for blocking electromagnetic waves emitted from PDPs and mobile phones. However, an electromagnetic wave shielding material having a high light-transmitting property and a sufficient electromagnetic wave shielding property requires a complicated process such as a photolithography method, is costly, and has a poor yield.

Further, in Japanese Patent Laid-Open No. 59-82499, a conductive layer such as copper or aluminum is deposited on a film or a transparent thin plate, and a conductive etching resist is predetermined on the conductive layer by a screen printing method or the like. After applying to the pattern of the above, it is dried and cured, the portion of the conductive layer not covered with the conductive etching resist is removed by etching, and a pattern consisting of the conductive layer and the conductive etching resist is formed on the film or transparent thin plate. A shielding plate is disclosed.

However, in this electromagnetic shielding plate, the layer of the conductive etching resist not only transmits the reflected light of the conductive layer but also the reflected light from the conductive layer exists.
Especially when the back side of the electromagnetic shielding plate is dark, the glittering feeling due to reflection is remarkable, and since the eyes are focused on the glittering surface, the electromagnetic shielding plate is used for electromagnetic shielding even though there is a see-through hole in the conductive etching resist. The back of the board is almost invisible.

Further, it takes not only a time to dry and cure the conductive etching resist on the conductive layer by a screen printing method or the like and then to dry and cure it.
The durability is not sufficient, and the conductive etching resist may be worn to expose the conductive layer, which may rust or oxidize a portion of the conductive layer to reduce the conductivity.

[0006]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide an electromagnetic wave shield material which is highly durable and which does not rust the conductive layer and which prevents glare from being visible, and an electromagnetic wave shield which is highly durable and has no conductive layer rust. It is to provide a method for manufacturing a material.

[0007]

The invention according to claim 1 solves the above-mentioned problems relating to the electromagnetic wave shielding material, and is an ionizing radiation in which a conductive metal film and a black pigment are dispersed on the surface of a transparent substrate. A gist of an electromagnetic wave shield material is characterized in that a shield pattern is provided which is composed of two layers of a print film of a curable ink and is composed of fine lines such as lattices, stripes, honeycomb patterns and geometric patterns.

In this electromagnetic wave shielding material, the conductive metal film is covered with a printed film of an ionizing radiation curable ink in which a robust black pigment is dispersed, so that the conductive metal film is rusted and discolored, or the conductivity is deteriorated by oxidation. It is not damaged. Further, since the black pigment is contained in the printed film, there is no visible glare, and there is no need for blackening treatment such as Ni plating to prevent glare.

In the electromagnetic wave shielding material of the present invention, the ratio Sb / Sa of the total area Sb of the region of the see-through portion which is not covered with the shield pattern to the total area Sa of the region where the shield pattern is formed is 1 or more and 9 or less. , The line width of the shield pattern is 1 to 150 μ, and more preferably 5 to 80 μm.
By setting μ and the film thickness to 0.5 to 50 μ, preferable high translucency can be obtained. When Sb / Sa is 1 or less, sufficient electromagnetic wave shielding performance cannot be secured.
On the other hand, when Sa / Sb exceeds 9, the printed film shields the light, and the electromagnetic wave shielding material itself does not have sufficient transparency.

Since the electromagnetic wave shielding material of the present invention has a high light-transmitting property, it can be applied not only to an optical filter of a PDP television, but also in the field of building materials, for example, by attaching it to a window frame or the like to form a window having an electromagnetic wave shielding property. It can be applied to applications such as

The present invention as set forth in claim 3 solves the above-mentioned problems relating to the method for producing an electromagnetic wave shield material, in which a conductive metal film is formed on the surface of a conductive substrate, and the surface of this metal film is ionized. A radiation-curable ink is used to form a patterned printed film consisting of fine lines such as lattices, stripes, honeycomb patterns, and geometric patterns by a printing method, and then a conductive metal not covered by the printed film by etching. 2 of the printed film and the conductive metal film by removing the film part
The gist is a method of manufacturing an electromagnetic wave shield material, which is characterized in that a shield pattern composed of layers is formed.

According to the method for producing an electromagnetic wave shielding material of the present invention, a strong and abrasion-resistant ink composed of fine lines such as lattices, stripes, honeycomb patterns and geometric patterns is formed by a printing method using an ionizing radiation curable ink. A printed film is obtained, and then the conductive metal film is coated with a robust printed film of ionizing radiation curable ink by removing the part of the conductive metal film not covered by the printed film by etching treatment. Therefore, it is possible to manufacture an electromagnetic wave shielding material in which the conductive metal film is not rusted and discolored or the conductivity is not impaired by oxidation.

By using an ionizing radiation curable ink containing a black pigment as the ionizing radiation curable ink, a printed film in which the black pigment is dispersed can be formed, and the black pigment is contained in the printed film. Therefore, it is possible to manufacture an electromagnetic wave shield material that does not appear glare. Also, by printing with flexographic printing, it is possible to continuously print the desired print film with an accuracy equal to or better than silk screen printing, and because the mechanism of the printing machine itself is simple, it is possible to use the operator's technology like offset printing. The print quality is not affected.

In the manufacturing method of the present invention, the ratio Sb / Sa of the total area Sb of the region of the see-through portion not covered with the shield pattern to the total area Sa of the region where the shield pattern is formed is 1 or more and 9 or less, When the line width of the shield pattern is 1 to 150 μ, more preferably 5 to 80 μ, and the film thickness is 0.5 to 50 μ, preferable high translucency can be obtained. When Sb / Sa is 1 or less, sufficient electromagnetic wave shielding performance cannot be secured. On the other hand, Sa /
When Sb exceeds 9, the printed film shields the light, and the electromagnetic wave shielding material itself does not have sufficient transparency.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION A method of manufacturing an electromagnetic wave shield material according to the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a conductive metal film is formed by depositing copper, aluminum or the like on a transparent substrate 1 such as polyethylene terephthalate (PET) or by adhering copper foil or the like through an adhesive. Form 2. Then, as shown in FIG. 2, an ionizing radiation curable ink containing a black pigment is used on the surface of the conductive metal film 2 by a printing method to form a pattern of fine lines such as lattices, stripes, honeycomb patterns, and geometric patterns. Printed film 3 is formed. Next, the conductive metal film 2 and the black pigment are dispersed on the surface of the transparent substrate 1 by removing the portion of the conductive metal film 2 not covered with the printed film 3 by an etching treatment, as shown in FIG. An electromagnetic wave shield material 5 having a shield pattern 4 composed of two layers of a printed film 3 of an ionizing radiation-curable ink and having fine lines such as lattices, stripes, honeycomb patterns and geometric patterns can be obtained.

The printing film 3 can be formed by a printing method such as silk screen printing or flexographic printing. In particular, flexographic printing makes it possible to continuously print a desired pattern equal to or more than silk screen printing, Further, since the mechanism of the printing machine itself is simple, there is an advantage that the printing quality is not influenced by the operator's technique like offset printing.

In the manufacturing method of the present invention, the total area Sb of the region of the transparent portion not covered with the shield pattern 4 to the total area Sa of the region where the shield pattern 4 is formed.
The ratio Sb / Sa of 1 to 9 is used, and the line width of the shield pattern 4 is 1 to 150 μ, more preferably 5 to 80 μ,
When the film thickness is 0.5 to 50 μm, preferable high translucency can be obtained. When Sb / Sa is 1 or less, sufficient electromagnetic wave shielding performance cannot be secured. On the other hand, when Sa / Sb exceeds 9, the printed film shields the light, and the electromagnetic wave shielding material itself does not have sufficient transparency.

FIG. 4 is a plan view showing a part of an example of a printing plate used for forming the printing film 3. Lines / spaces in this printing plate are, for example, 40/250, 30/250,
20/250 (Sb / Sa ratio of 2.9,
3.9, 6.0).

Here, when the pattern of the printed film is a line such as a lattice pattern, and especially when it is formed by a fine line, when the pattern is a pattern having intersections between the lines,
In particular, thick lines may be noticeable at the intersections. This is because, on the plate surface of the printing plate, the intersections of the image line portions become thick due to the characteristics of the plate making, or the ink spreads and becomes fat especially at the intersections during printing. In particular, when printing with one plate during flexographic printing, thickening is likely to occur at the intersections of lines. Electromagnetic wave shield material 10 shown in FIG.
The plan view of is an example, and the printed film 3 is formed in a pattern with a rhombic lattice pattern, and the line becomes thicker at the intersection point C of the lines forming the printed film 3, and the area of the opening A is correspondingly increased. It shows a decreasing state.

When the line becomes thick at the intersection of the lines as described above, the pattern having the intersections of the lines of the lattice pattern or the like is not formed by one printing, but the lines of the stripe pattern or the like intersects each other. It is advisable to avoid the line thickening at the intersection point by forming the pattern by overprinting using at least two or more plates of a pattern not having. That is, instead of forming the pattern of the printing film 3 by using a single printing plate, it is preferable to form a combination of these patterns by using a plurality of printing plates having a pattern having no intersection. The thickening prevention effect by this has a great effect on the aperture ratio improvement when the line is particularly thin.

FIG. 6 is a conceptual explanatory view showing a case where the pattern forming method by overprinting is applied to the pattern of FIG. That is, the printing plate Pa shown in FIG.
It is a plate for printing and forming a diagonally striped pattern composed of a plurality of diagonal straight lines with a line La. On the other hand, FIG.
The printing plate Pb shown in FIG. 6B has a diagonal stripe pattern, which is opposite to that of FIG.
It is a plate for printing and forming with. Printing plate Pa and printing plate P
It does not matter which of the colors b is the first color and may be printed first. However, if overprinting is performed using both the printing plate Pa and the printing plate Pb, as a result, as shown in FIG. A pattern having a line intersection may be formed as the printed film 3 as a diamond-shaped lattice pattern. The printed film 3 formed in this manner does not cause a thickening at the intersection.

According to the production method of the present invention, an ionizing radiation curable ink containing a black pigment is used, and a grid is formed by a printing method.
A strong and abrasion-resistant printed film 3 in which a black pigment is dispersed in a pattern made up of thin lines such as stripes, honeycomb patterns, and geometric patterns is obtained.
By removing the portion of the conductive metal film 2 which is not covered with the printing film 3, it has high light-transmitting property and an electromagnetic wave shielding property of about 40 dB or 40 dB or more in the frequency range of 1 GHz or less and 1 to 5 GHz. It is possible to obtain an electromagnetic wave shielding material that has the above and is much cheaper than the conventional one. Printed film 3 of ionizing radiation-curable ink whose conductive metal film 2 is robust
Therefore, the conductive metal film 2 is not rusted and discolored, or the conductivity is not impaired by oxidation, and since the black pigment is contained in the printed film, there is no visible glare. It is possible to manufacture a non-electromagnetic wave shielding material 5. Also, by forming by flexographic printing, it is possible to continuously print the desired shield pattern with the same or higher accuracy as silk screen printing, and because the mechanism of the printing machine itself is simple, it is possible to use the operator's technology like offset printing. The print quality is not affected.

Specific examples of the black pigment include carbon black, graphite, iron black, nickel sulfide, copper sulfide, silver sulfide and lead sulfide.

The ionizing radiation curable ink is an ink in which an ionizing radiation curable resin is used as an ink binder. Specifically, a (meth) acryloyl group in the molecule,
Radical-polymerizable unsaturated bond such as (meth) acryloyloxy group (((meth) acryloyl means acryloyl or methacryloyl)), or a prepolymer having an epoxy group, an oligomer, and / or a monomer are appropriately mixed, A composition curable by ionizing radiation is used. The ionizing radiation means an electromagnetic wave or a charged particle beam having an energy quantum capable of polymerizing or crosslinking a molecule, and usually an ultraviolet ray or an electron beam is used.

Examples of the above prepolymers and oligomers include unsaturated polyesters of condensation products of unsaturated dicarboxylic acids and polyhydric alcohols, polyester (meth) acrylates, urethane (meth) acrylates, polyether (meth) acrylates, polyols ( (Meth) acrylate,
Examples thereof include (meth) acrylates such as silicon (meth) acrylate, triazine (meth) acrylate, and melamine (meth) acrylate (where (meth) acrylate means acrylate or methacrylate).

Examples of the monomer used for the ionizing radiation curable resin include styrene, styrene-based monomers such as α-methylstyrene, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and (meth) acrylate. )
(Meth) acrylic acid esters such as butyl acrylate, methoxyethyl (meth) acrylate, ethoxymethyl (meth) acrylate, phenyl (meth) acrylate, and lauryl (meth) acrylate, (meth) acrylic acid-2 −
Unsaturated substitution of (N, N-dimethylamino) ethyl, (meth) acrylic acid-2- (N, N-dibenzylamino) methyl, (meth) acrylic acid-2- (N, N-diethylamino) propyl, etc. Substituted amino alcohol esters, unsaturated carboxylic acid amides such as (meth) acrylamide, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, neopentyl glycol di (meth) Acrylate, 1,6 hexanediol di (meth) acrylate, compound of triethylene glycol di (meth) acrylate layer, dipropylene glycol di (meth) acrylate, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, Jiechi Polyfunctional compounds such as glycol glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (tetra) (meth) acrylate, dipentaerythritol hexa (meth) acrylate and / or in the molecule Examples thereof include polythiol compounds having two or more thiol groups, such as trimethylolpropane trithioglycolate, trimethylolpropane trithiopropylate, and pentaerythritol tetrathioglycol. [In the present invention, (meth) acrylate is used in the meaning of acrylate or methacrylate] Usually, one kind or two or more kinds of the above compounds are mixed and used, but it is usually used for ionizing radiation curable resins. In order to impart coating suitability, the above-mentioned prepolymer or polythiol 5 is added.
9% by weight or more of the monomer and / or polythiol
It is preferably 5% by weight or less.

Further, an ionizing radiation non-curable resin may be added to the ionizing radiation curable resin in order to adjust physical properties such as flexibility and surface hardness of the cured product. As the ionizing radiation non-curable resin, a thermoplastic resin such as urethane resin, fibrin resin, polyester resin, acrylic resin, butyral resin, polyvinyl chloride, or polyvinyl acetate is used, and particularly, fibrin resin, urethane resin. , Butyral type is preferable from the viewpoint of flexibility.

Examples of the compound having a cationic polymerization type functional group include epoxy type resins such as bisphenol type epoxy resin and novolac type epoxy compound, and vinyl ether type resins such as fatty acid type vinyl ether and aromatic vinyl ether.

When ultraviolet rays are irradiated to cure the ionizing radiation curable resin having the above composition, a prepolymer having a radical-polymerizable unsaturated bond as a photoinitiating polymerization agent and acetophenone as a monomer are used. , Benzophenones, Michler benzoyl benzoate, α-aminoxime ester, tetramethyl thiuram monosulfide, thioxanthone, for cationically polymerizable epoxy compounds, aromatic diazonium salts,
Aromatic sulfonium salts, metallocenes and the like are used. Further, n-butylamine as a photopolymerization accelerator (sensitizer),
Triethylamine, tri-n-butylphosphine and the like can be further mixed and used.

[0031]

EXAMPLES (Example 1) A polyethylene terephthalate film (100U-9 manufactured by Toray Industries, Inc.) that has been subjected to an easy-adhesion treatment.
After bonding a rolled copper foil (thickness: 3 to 5 μm) to a thickness of 4, 100), a UV curable ink (Inktech Co., Ltd., epoxy acrylate-based carbon-containing ink, UFL ink, P)
/ V ratio: about 25%) by flexographic printing method using a grid pattern (line 30 μ width, space 250 μ width, S
b / Sa = 3.9) was printed. In this case, in order to prevent the thickening of the intersections from occurring, printing was performed using two plates having a pattern in which the mutual lines do not have the intersections.

The printed matter printed as above is
The rolled copper foil portion corresponding to the non-printed portion was dissolved and removed by immersing in a ferric chloride aqueous solution at 30 ° C. for about 30 seconds to obtain an electromagnetic wave shielding material. This electromagnetic wave shielding material has a high translucency, and
40 GHz or less and 1 to 5 GHz frequency range
It had an electromagnetic wave shielding performance of ˜50 dB.

Example 2 A polyethylene terephthalate film (100U-9 manufactured by Toray Industries, Inc.) which has been subjected to an easy-adhesion treatment.
After vacuum-depositing aluminum to a thickness of 3 μm on a thickness of 4,100), UV curable ink (Inktech Co., Ltd., epoxy acrylate-based carbon-containing ink, UFL ink, P /
V ratio: about 25%) by flexographic printing method using a grid pattern (line 30 μ width, space 250 μ width, Sb
/Sa=3.9) was printed. Also in this case, in order to prevent the thickening of the intersections, printing was performed using two plates having a pattern in which the lines do not have the intersections.

The printed matter printed as described above is printed in 10
% Sodium hydroxide aqueous solution, and the rolled copper foil portion corresponding to the non-printed portion was dissolved and removed to obtain an electromagnetic wave shielding material. This electromagnetic wave shield material has a high translucency and has a frequency of 1 GHz.
The electromagnetic wave shielding performance was 30 dB in the following and 1 to 5 GHz frequency ranges.

(Comparative Example) An attempt was made to form a patterned printing film by gravure printing in the same manner as in Example 1. However, swimming on the entire surface, doctor's muscles, and thickening of the line were observed. Further, since the printed film has the above-mentioned defects, it is impossible to form a shield pattern having a good shape. Further, there is a print defect in the print film, and the copper foil portion exposed through the print defect portion is contaminated with the solvent, so that a good electromagnetic wave shielding material cannot be obtained.

[0036]

As described in detail above, in the electromagnetic wave shielding material of the present invention, the conductive metal film is coated with the printing film of the ionizing radiation curable ink in which the robust black pigment is dispersed, and therefore the conductive film The conductive metal film is not rusted and discolored, or the conductivity is not impaired by oxidation. In addition, since the black pigment is contained in the printed film, there is no glare in appearance, and there is an advantage that blackening treatment by Ni plating or the like for preventing glare is unnecessary.

According to the method for producing an electromagnetic wave shielding material of the present invention, a strong and abrasion resistant pattern of fine lines such as lattices, stripes, honeycomb patterns and geometric patterns is formed by a printing method using an ionizing radiation curable ink. A printed film of ionizing radiation-curable ink in which the conductive metal film is robust by removing a portion of the conductive metal film that is not covered with the printed film by an etching treatment afterwards to obtain a printed film with excellent properties. Since it is covered, it is possible to manufacture an electromagnetic wave shield material in which the conductive metal film is not rusted and discolored, or the conductivity is not impaired by oxidation. Further, since the black pigment is contained in the printed film, it is possible to manufacture an electromagnetic wave shield material that does not appear glare.
In addition, by using flexographic printing, it is possible to continuously print desired shield patterns with an accuracy equal to or better than silk screen printing, and because the mechanism of the printing machine itself is simple, operators like offset printing can be used. The technology does not affect the quality of printing.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state in which a conductive metal film is provided on a transparent base material.

FIG. 2 is a cross-sectional view showing a state in which a printed film is formed on a conductive metal film.

FIG. 3 is a diagram showing a state in which a conductive metal film is etched using a printed film as a resist pattern.

FIG. 4 is a plan view showing an example of a printing plate.

FIG. 5 is a plan view showing an example of an electromagnetic wave shield having a printed film with a lattice pattern.

FIG. 6 is a conceptual explanatory diagram showing a case where a pattern forming method by overprinting is applied to the pattern of FIG.

[Explanation of symbols]

1 Transparent base material 2 Conductive metal film 3 printing film 4 shield pattern 5 Electromagnetic wave shield material A opening C intersection point La, Lb line Pa, Pb version

Continued front page    F-term (reference) 4F100 AB01B AB17B AK42A AT00A                       BA03 BA10A BA10C CA13C                       CC00C EC181 EH462 EJ152                       HB31B HB31C JB14C JD08                       JG01A JG01B JN01A YY00                 5E321 AA01 AA46 AA50 BB23 GH01                       GH10

Claims (6)

[Claims] 1. A printed film of an ionizing radiation-curable ink in which a conductive metal film and a black pigment are dispersed on the surface of a transparent substrate.
An electromagnetic wave shielding material, which is provided with a shield pattern composed of layers, each of which is a thin line such as a lattice, a stripe, a honeycomb pattern, or a geometric pattern. 2. The ratio Sb / Sa of the total area Sb of the region of the see-through portion not covered with the shield pattern to the total area Sa of the region where the shield pattern is formed is 1 or more and 9 or less, and the line of the shield pattern is The electromagnetic wave shielding material according to claim 1, wherein the width is 1 to 150 μm and the film thickness is 0.5 to 50 μm. 3. A conductive metal film is formed on the surface of a conductive base material, and an ionizing radiation-curable ink is used on the surface of this metal film by a printing method to form fine lines such as lattices, stripes, honeycomb patterns, and geometric patterns. Forming a patterned printed film consisting of, and then performing an etching treatment to remove the portion of the conductive metal film not covered by the printed film to form a shield pattern consisting of two layers of the printed film and the conductive metal film. A method of manufacturing an electromagnetic wave shield material, comprising: 4. The method for producing an electromagnetic wave shielding material according to claim 3, wherein an ionizing radiation curable ink containing a black pigment is used as the ionizing radiation curable ink. 5. The ratio Sb / Sa of the total area Sb of the area of the see-through portion not covered with the shield pattern to the total area Sa of the area where the shield pattern is formed is 1 or more and 9 or less, and the line of the shield pattern is The method for producing an electromagnetic shielding material according to claim 3 or 4, wherein the width is 1 to 150 µ and the film thickness is 0.5 to 50 µ. 6. The method for producing an electromagnetic wave shielding material according to claim 3, wherein the printed film is formed by a flexographic printing method.