JP4398894B2 - Copper foil for electromagnetic wave shielding, and electromagnetic wave shield made with the copper foil - Google Patents

Description

  The present invention mainly relates to a copper foil suitable for use as an electromagnetic shield for a display, and more specifically as a material for producing an electromagnetic shield suitable for use in a plasma display panel (hereinafter sometimes referred to as PDP). The present invention relates to a copper foil and an electromagnetic wave shield made of the copper foil.

  As electronic devices such as optoelectronic components have become more sophisticated, these devices have made significant progress. Among them, displays for displaying images have been remarkably spread for television receivers, computer monitor devices, and the like. In recent years, among them, market demands for increasing the size and thickness of displays have increased, and recently, PDPs that have become large and thin have attracted attention.

  However, in principle, the PDP emits strong electromagnetic waves outside the device. Electromagnetic waves may cause damage to various instruments, and recently, electromagnetic waves also have an effect on the human body, so legal regulations regarding electromagnetic wave emission have become stricter. For example, the Electrical Appliance and Material Control Law, VCCI (Voluntary Control Council for Information by data processing equipment electronic machinery), FCC (Federal Communication Commission) and other products.

  It is essential that the electromagnetic wave shield has conductivity over the entire shield surface and is excellent in transparency. As an electromagnetic wave shield body that satisfies this requirement and has been put into practical use, there is one in which a transparent conductive thin film is disposed on the entire surface of the PDP. However, this product has a problem in transparency because the transmittance of the transparent conductive layer itself is reduced when an electromagnetic wave shielding ability of, for example, 60 dB or more is obtained.

In order to solve the above problems, a method has been proposed in which a metal fiber knitted in a mesh shape is sandwiched between a film, glass, and a polymer substrate to form an electromagnetic wave shield. However, knitting of metal fibers is likely to be kinked, and problems with appearance such as moire patterns occur when combined with PDP.
Therefore, a method has been proposed in which a metal foil, particularly copper foil, is bonded to a transparent polymer film using an adhesive, and then a mesh pattern is formed on the metal foil by etching. Since it becomes substantially opaque, it was a difficult task how to increase the transmittance.

The applicant of the present application, as a copper foil suitable for producing an electromagnetic wave shield body having excellent electromagnetic wave shielding ability and high transmittance, has the characteristics that the black-treated surface has a uniform color tone, no color spots, and no powder loss. A copper foil was developed and filed (Patent Documents 1 and 2). These copper foils are used for mass production because of their excellent characteristics. However, since then, the required characteristics for PDP have become sophisticated, and a foil having a back surface that hardly causes light reflection has come to be demanded. This is because the reflection of light on the back surface leads to the color blur of the PDP.
JP 2004-260068 A Japanese Patent Application No. 2003-38398

The problem to be solved by the present invention is to provide a copper foil in which light bleeding hardly occurs in a PDP.
Another object of the present invention is to provide an excellent copper foil as a material for producing an electromagnetic wave shield for PDP, and an electromagnetic wave shield that can be suitably used for a PDP produced using the copper foil.

In the first aspect of the present invention, a black or brown treatment layer made of fine roughened particles is provided on one side of an original foil made of copper foil or copper alloy foil, and the black or brown treatment provided on the one side is provided on the other side. A copper foil for electromagnetic wave shielding, characterized in that a blurring-preventing treatment layer having a color tone lighter than the color tone of the layer is provided.

In the second aspect of the present invention, a black or brown treated layer made of fine roughened particles is provided on one side of an original foil made of copper foil or copper alloy foil, and a smooth layer is provided on the black to brown treated layer, The copper foil for electromagnetic wave shielding is characterized in that a black or brown color bleed prevention treatment layer having a color tone lighter than the color tone of the black or brown treatment layer provided on the one side is provided on the other side.

  The fine roughening particles forming the black or brown treated layer are one or more of the first fine particle group consisting of copper, copper-cobalt, copper-nickel, cobalt-nickel, copper-cobalt-nickel. It is preferable to form a black or brown treated layer by laminating one or more layers of the composition.

  A copper alloy containing at least one of the second finely roughened particle groups in which the finely roughened particles forming the black or brown treated layer are composed of Se, Sb, W, Te, Bi, Mo, and Fe is preferable. One or more layers of the composition may be laminated to form a black or brown treated layer.

  The black or brown treatment layer is composed of one or more kinds of compositions of a first finely roughened particle group composed of copper, copper-cobalt, copper-nickel, cobalt-nickel, copper-cobalt-nickel. Second fine roughening made of a copper alloy containing at least one member of the second fine roughening particle group made of Se, Sb, W, Te, Bi, Mo, Fe on the first fine roughened particle layer. A particle layer may be stacked.

  The smooth layer may be formed of one or more kinds of compositions of copper, cobalt, nickel, indium or alloys thereof.

  The color bleed prevention treatment layer is formed of a first or second composition composed of one or more of the first finely-roughened particles consisting of copper, copper-cobalt, copper-nickel, cobalt-nickel, and copper-cobalt-nickel. 1st fine roughening particle layer, 2nd fine roughening particle layer which consists of a copper alloy containing at least any 1 type from the 2nd fine roughening particle group which consists of Se, Sb, W, Te, Bi, Mo, and Fe Or at least one smooth layer composed of one or more of copper, cobalt, nickel, indium or alloys thereof, and the color blur preventing treatment layer reflects light. It is desirable that the thickness is sufficient to suppress it.

The smooth layer may be formed of a Co alloy containing a Cu content of 5% or less.
Furthermore, the surface roughness Rz of the smooth layer surface is preferably 3.5 μm or less.

  It is preferable that the surface roughness Rz of the surface of the original foil made of the copper foil or the copper alloy foil is a granular crystal having a size of 3 μm or less.

  It is preferable that a rust prevention treatment and a silane coupling agent treatment are performed on the fine roughened particle layer or the smooth layer.

  A third aspect of the present invention is an electromagnetic wave shielding body made of the copper foil for electromagnetic wave shielding according to the first and second inventions.

  The copper foil for electromagnetic wave shielding of the present invention has a light bleed prevention treatment layer on the back surface, which hardly causes light reflection, and therefore has little bleed of PDP light and can be suitably used as a copper foil for electromagnetic wave shielding. In addition, the use of the copper foil has an excellent effect of providing a good electromagnetic wave shield that can be used for PDP and the like.

  The copper foil for electromagnetic wave shielding of the present invention uses an electrolytic copper foil and a rolled copper foil as a base foil. The copper foil for electromagnetic wave shielding of the present invention is provided with a black or brown treatment layer made of fine roughened particles on one surface of an original foil made of electrolytic copper foil or rolled copper foil, and suppresses light reflection on the other surface. A layer that has been subjected to an anti-bleeding treatment layer. The black or brown treatment layer is preferably one in which one or several finely-grained particles of copper, copper alloy or cobalt-nickel alloy are provided, or the film thickness is adjusted by adjusting the electrolytic treatment time and current density. is there. The smooth layer provided on the black or brown treatment layer is one in which one or several layers of Cu, Co, Ni, In or their alloys are provided, or the film thickness is adjusted by adjusting the electrolytic treatment time or current density. .

  The reason for providing a black or brown treated layer made of finely-roughened particles of copper or the above alloy on the surface of the original foil is to make the surface easily diffused by making the surface of the original foil a layer of fine particles, and to reduce the reflectance. It is. The lower the reflectivity, the greater the blackness and the greater the contrast, so a clear PDP screen can be obtained when viewed with the naked eye.

In addition, the light bleed prevention treatment layer that suppresses light reflection is applied to the other surface in order to prevent light bleed due to light from the light source unit installed on the back side being scattered on the back side of the copper foil. Therefore, it is not necessary to be blackened as much as the copper foil surface on the naked eye side, and it is sufficient that the surface treatment is performed to such an extent that light bleeding can be prevented.
When the fine roughened particle layer is formed of Cu, Cu—Co alloy, Cu—Ni alloy, Co—Ni alloy, Cu—Co—Ni alloy (hereinafter sometimes abbreviated as copper or alloy), these This is because copper or an alloy is easily formed into fine rough particles, and a fine rough particle layer surface in which fine rough particles are uniformly distributed can be formed, which is preferable.
If necessary, a smooth layer is provided on the outer layer of the black or brown treated layer. The reason why the smooth layer is provided is to effectively prevent the so-called dust-off phenomenon that the fine roughened particle layer formed on the copper foil surface falls when it touches the container or the like in the processing of the lower process.

In the copper foil for electromagnetic wave shielding provided with the smooth layer of the present invention, the brightness (reflectance) affecting the contrast and the powder-off phenomenon are related to the thickness of the smooth layer. That is, if the thickness of the smooth layer is thick, the brightness increases but the powder fall is small. Conversely, if the thickness is thin, the brightness decreases but the powder fall increases.
The thickness of the black or brown treatment layer made of finely roughened particles formed of copper or an alloy depends on the color required for the electromagnetic wave shield, and when a dark black color is required, the deposited layer of the finely roughened particle layer Or increase the electrolysis time (thicken the thickness), and if thin black (brown) is required, use 1 to 3 layers, or shorten the electrolysis time (thicken the thickness). . Moreover, the smooth layer provided as necessary on the black or brown treated layer affects the black or brown shading on the surface of the copper foil. Therefore, the number of smooth layers or the electrolysis time (thickness) is arbitrarily selected according to the shade of the black or brown treatment layer, and a film thickness is deposited according to the demand for black or brown shades, but the effect on lightness is ignored. I can't do it.

  In the copper foil for electromagnetic shielding according to the present invention, a black or brown treatment layer made of fine roughened particles is directly provided on the surface of the original foil. Depending on the roughness of the surface of the copper foil, copper or copper alloy plating is provided on the surface of the copper foil. The first fine particle layer is provided by the above, and the second fine rough particle layer of fine rough particles made of Cu—Co alloy, Cu—Ni alloy, Co—Ni alloy, Cu—Co—Ni alloy is provided thereon. It is preferable that the surface roughness Rz of the copper foil surface be 3 μm or less by the first fine roughening particle layer.

  That is, a first fine roughened particle layer is first applied on a copper foil by copper or copper alloy plating. This first fine roughened particle layer has a constant roughness on the surface of the copper foil, and in part, even if the thickness of the second fine roughened particle layer provided thereon is reduced, a black to brown hue is obtained. This is because a thickening effect can also be expected. Second, since the black color can be darkened by providing the first fine roughening particle layer, the thickness of the second fine roughening particle layer can be reduced, and the first fine roughening particle layer is made of copper foil. Since the two are close to each other, the adhesive strength between them is strong, and the second fine particles composed of finely roughened particles of Cu—Co alloy, Cu—Ni alloy, Co—Ni alloy, and Cu—Co—Ni alloy provided thereon. This is because the coarsened particle layer can be made thinner, so that the powder falling phenomenon is reduced, and the smooth layer can be omitted or made thinner.

Moreover, depending on the manufacturing method of a PDP electromagnetic wave shield plate, after a copper foil pattern is created by etching, a blackening treatment may be performed on the copper foil surface on the side not adhered to the film and the pattern side surface that appears by pattern creation. .
In this case, pretreatment with an acid is performed prior to the black or brown treatment, but when the black or brown treatment layer is a roughened particle layer containing a large amount of Co, the roughened particle layer is dissolved by this acid treatment. The pattern portion may be eroded by acid. Therefore, as a copper foil used in the manufacturing process in which such acid treatment is performed, a fine roughening such as a Cu—Ni alloy containing no Co or a Cu—Co—Ni alloy containing only a very small amount of Co. Treatment is preferred.

  Further, various surface treatments may be performed on the black or brown treatment layer or the smooth layer. Specifically, rust prevention treatment such as chromate treatment, pickling treatment, zinc / chromate treatment, or silane coupling agent treatment.

  The thickness of the copper foil (original foil) is preferably 3 μm to 30 μm, more preferably 5 to 20 μm, and still more preferably 7 to 12 μm. If it is thicker than this thickness, it takes time for etching, and if it is thinner than this thickness, handling of the copper foil becomes extremely difficult.

When the copper foil is used for electromagnetic wave shielding, the aperture ratio of the light transmitting portion is preferably 60% or more and 97% or less, more preferably 70% or more, and a larger aperture ratio is preferable.
The shape of the opening is not particularly limited, but a regular triangle, a regular square, a regular hexagon, a circle, a rectangle, a rhombus, and the like are aligned, and a shape that is uniformly arranged in the plane is preferable. A typical size of the opening of the light transmitting portion is in the range of one side or diameter of 100 to 300 μm. This is because when this value is too large, the electromagnetic wave shielding ability is lowered, and when it is too small, the display image is unfavorably affected.

  Moreover, as for the width | variety of the copper foil of the part which does not form an opening part, 5-50 micrometers is preferable. That is, the pitch is preferably 100 to 350 μm. This is because if the width is smaller than this width, the etching process becomes extremely difficult, and if the width is larger than this width, the image is unfavorably affected.

  The substantial sheet resistance of the copper foil having a light transmitting portion is measured by a four-terminal method using an electrode that is 5 times or more larger than the above pattern and having an electrode interval of 5 times or more than the repeating unit of the above pattern. Can do. For example, if the shape of the opening is a square with a side of 100 μm and the square of the metal layer is regularly arranged with a width of 20 μm, it is possible to measure by arranging electrodes of φ1 mm at intervals of 1 mm. Alternatively, the film on which the pattern is formed is processed into a strip shape, electrodes are provided at both ends in the longitudinal direction, the resistance is measured (R), the length in the longitudinal direction is a, and the length in the lateral direction is b. Then, a substantial sheet resistance can be obtained by resistance = R × b / a. The value thus measured is preferably 0.005Ω / □ or more and 0.5Ω / □ or less, more preferably 0.01Ω / □ or more and 0.3Ω / □ or less. If an attempt is made to obtain a value smaller than this value, the film becomes too thick and the opening cannot be sufficiently removed. On the other hand, if the value is larger than this value, sufficient electromagnetic wave shielding ability cannot be obtained.

  As the resin substrate to be bonded to the electromagnetic shielding copper foil of the present invention, a transparent polymer film having appropriate heat resistance and transparency is preferable. Regarding the heat resistance, the glass transition temperature is at least 40 ° C. A transparent polymer film having a light transmittance of 550 nm of at least 80% or more is preferable.

  Transparent polymer films include polysulfone (PSF), polyethersulfone (PES), polyethylene terephthalate (PET), polymethylene methacrylate (PMMA), polycarbonate (PC), polyetheretherketone (PEEK), polypropylene (PP) And triacetylcellulose (TAC).

  As a method for adhering the electromagnetic shielding copper foil of the present invention to a resin substrate, after applying a transparent adhesive such as acrylic, epoxy, urethane, silicone, polyester, etc. to a polymer film, Paste. Or an adhesive agent can be apply | coated and bonded together to copper foil.

  A printing method or a photoresist method is used as a method for forming the light transmission portion on the copper foil for electromagnetic wave shielding. In the printing method, the mask layer is screen-printed with a printing resist material to form a pattern. In the method using a photoresist material, a photoresist material is formed on a metal foil by a roll coating method, a spin coating method, a full surface printing method, a transfer method, etc., and the resist is patterned by exposure and development using a photomask. . After the resist patterning is completed, the copper foil portion used as the opening is removed by etching, and a copper foil layer having a light transmitting portion having a desired opening shape and an opening ratio is provided.

  The surface light reflectance of the copper foil for electromagnetic wave shielding is desirably 1% or more and 50% or less. This is because when the copper foil for electromagnetic wave shielding is used as a translucent electromagnetic wave shielding body, the reflection of light hinders visibility. The reflectivity is generally an average reflectivity from 400 nm to 600 nm, but the reflectivity here is determined by representing the reflectivity of light having a wavelength of 550 nm, assuming that there is no wavelength dependency.

  The smooth layer provided as necessary to prevent powder falling is formed by smooth plating of Cu, Co, Ni, In or an alloy thereof. The reflectivity of the copper foil for electromagnetic wave shielding depends on the thickness of the fine roughened particle layer and the smooth layer, but the number of layers (thickness) of the smooth layer for obtaining the reflectivity: 1% to 50% is particularly It is not necessary to be thick, and a suitable range is substantially 5 nm or more and 100 nm or less. If it is thinner than this, powder fall-off cannot be prevented, and if it is more than this, the reflectivity becomes high, which is also a waste of material.

  Next, the present invention will be specifically described with reference to examples. The present invention is not limited by the following examples.

Example 1
A fine roughened particle layer (corresponding to a black or brown treated layer, referred to as a finely roughened particle layer in the description of the following examples) is formed by copper plating on one surface of an electrolytic copper foil (original foil) having a thickness of 12 μm. Subsequently, a color blur preventing treatment layer was formed on the other surface.
Plating conditions for fine roughening particle layer Plating bath composition Cu (as metal): 8 g / l
Co (as metal): 2 g / l
Ni (as metal): 0.5 g / l
Ammonium sulfate: 5 g / l
Sodium chloride: 2 g / l
pH: 4.0-6.0
Plating conditions Temperature: 40 ° C
Current density: 40 A / dm ²
Treatment time: 8 seconds As a result of analysis of the composition of the fine roughened particle layer plated under the above conditions, Cu: 13.8, Co: 2.6, Ni: 0.5 as an actual composition mg / dm ² foil. It was.

Color blur prevention treatment layer plating conditions Plating bath composition Cu (as metal): 8 g / l
Co (as metal): 2 g / l
Ni (as metal): 0.5 g / l
Ammonium sulfate: 5 g / l
Sodium chloride: 2 g / l
pH: 4.0-6.0
Plating conditions Temperature: 40 ° C
Current density: 20 A / dm ²
Treatment time: 8 seconds As a result of analysis of the composition of the fine roughened particle layer plated under the above conditions, the actual composition was mg / dm ² foil; Cu: 19, Co: 1.8, Ni: 0.3.

Example 2
A fine roughening particle layer was formed by copper plating on one surface of an electrolytic copper foil having a thickness of 10 μm, and then a color blur preventing treatment layer was formed on the other surface.
Plating conditions for fine roughening particle layer Plating bath composition Cu (as metal): 8 g / l
Ni (as metal): 1 g / l
Citric acid 3Na: 76 g / l
Sodium chloride: 2g / l
Ammonium sulfate: 5 g / l
pH: 4.5-5.0
Plating conditions Temperature: 55 ° C
Current density: 40 A / dm ²
Treatment time: 8 seconds The composition of the fine roughened particle layer plated under the above conditions was analyzed, and as a result, the actual composition mg / dm ² foil was Cu: 22.7 and Ni: 1.8.

Color blur prevention treatment layer plating conditions Plating bath composition Cu (as metal): 8 g / l
Ni (as metal): 1 g / l
Citric acid 3Na: 76 g / l
Sodium chloride: 2g / l
Ammonium sulfate: 5 g / l
pH: 4.5-5.0
Plating conditions Temperature: 55 ° C
Current density: 20 A / dm ²
Treatment time: 8 seconds The composition of the fine roughened particle layer plated under the above conditions was analyzed. As a result, the actual composition was mg / dm ² foil, and Cu: 15.2 and Ni: 1.5.

Example 3
A first fine roughened particle layer formed by Cu plating is provided on one surface of an electrolytic copper foil having a thickness of 12 μm, a second fine roughened particle layer made of Co—Ni is applied on the first fine roughened particle layer, and then A color bleed prevention layer was formed on one surface.
Plating conditions for first fine grained particle layer Plating bath composition Copper sulfate (as Cu metal): 5.3 g / l
Sulfuric acid: 42 g / l
Arsenic: 240 ppm
Plating conditions Temperature: 18 ° C
Current density: 18 A / dm ²
Treatment time: 6 seconds The adhesion amount of the fine copper particles plated under the above conditions to the copper foil was 9.9 mg / dm ² .

Plating conditions for second refined particle layer Plating bath composition Cobalt sulfate (as Co metal): 8 g / l
Nickel sulfate (as Ni metal): 1 g / l
Ammonium sulfate: 40 g / l
Boric acid: 20 g / l
pH: 3.5
Plating conditions Temperature: 40 ° C
Current density: 30 A / dm ²
Treatment time: 3 seconds As a result of analysis, the composition of the alloy fine-roughened particle layer plated under the above conditions was as follows: actual composition mg / dm ² foil; Co: 9.5, Ni: 1.1.

Plating conditions for the color bleed prevention treatment layer Plating bath composition Cobalt sulfate (as Co metal): 8 g / l
Nickel sulfate (as Ni metal): 1 g / l
Ammonium sulfate: 40 g / l
Boric acid: 20 g / l
pH: 3.5
Plating conditions Temperature: 40 ° C
Current density: 30 A / dm ²
Treatment time: 3 seconds As a result of analysis, the composition of the alloy fine-roughened particle layer plated under the above conditions was as follows: actual composition mg / dm ² foil; Co: 9.5, Ni: 1.1.

Example 4
A fine roughening particle layer was applied to one surface of an electrolytic copper foil having a thickness of 10 μm by copper plating, and then a color blur preventing layer was formed on the other surface.
Plating conditions for fine roughening particle layer Plating bath composition Cu (as metal): 15 g / l
Sulfuric acid: 160 g / l
Sodium selenite: 0.015 g / l
Plating conditions Temperature: 20 ° C
Current density: 20 A / dm ²
Treatment time: 1.5 seconds The amount of finely roughened particles plated under the above conditions adhered to the copper foil was 5.4 mg / dm ² .

Plating conditions for the color bleed prevention layer Plating bath composition Cu (as metal): 15 g / l
Sulfuric acid: 160 g / l
Sodium selenite: 0.015 g / l
Plating conditions Temperature: 20 ° C
Current density: 20 A / dm ²
Treatment time: 1.5 seconds The amount of finely roughened particles plated under the above conditions adhered to the copper foil was 5.4 mg / dm ² .

Example 5
First, the first fine roughened particles were applied to one side of the electrolytic copper foil having a thickness of 10 μm by copper plating, and the second fine roughened particle layer made of a copper alloy was plated on the first fine roughened particle layer. . Next, a color bleed prevention layer was formed on the other surface.
Plating conditions for the first finer grained particle layer Plating bath composition Cu (as metal): 65 g / l
Sulfuric acid: 120 g / l
Plating conditions Temperature: 50 ° C
Current density: 65 A / dm ²
Treatment time: 1.2 seconds The adhesion amount of the finely roughened particles plated under the above conditions to the copper foil was 21.8 mg / dm ² .

Plating conditions for second finer grained particle layer Plating bath composition Cu (as metal): 10 g / l
Fe (as metal): 4 g / l
Mo (as metal): 0.3 g / l
W (as metal): 0.3 ppm
pH: 2.5
Plating conditions Temperature: 20 ° C
Current density: 50 A / dm ²
Treatment time: 1.2 seconds The adhesion amount of the fine roughened particles plated under the above conditions was 5.6 mg / dm ² .

Plating condition of the color blur preventing treatment layer Plating bath composition Cu (as metal): 10 g / l
Fe (as metal): 4 g / l
Mo (as metal): 0.3 g / l
W (as metal): 0.3 ppm
pH: 2.5
Plating conditions Temperature: 20 ° C
Current density: 50 A / dm ²
Treatment time: 1.2 seconds The adhesion amount of the fine roughened particles plated under the above conditions was 5.6 mg / dm ² .

Example 6
First, fine roughening particles were applied to one surface of an electrolytic copper foil having a thickness of 10 μm by copper plating, and a smooth layer made of Cu and Co was formed on the fine roughening particle layer under the following plating conditions. Next, a color bleed prevention layer was formed on the other surface.
Plating conditions for fine roughening particle layer Plating bath composition Cu (as metal): 10 g / l
Fe (as metal): 4 g / l
Mo (as metal): 0.3 g / l
W (as metal): 0.3 ppm
Sulfuric acid: 160 g / l
Plating conditions Temperature: 20 ° C
Current density: 50 A / dm ²
Treatment time: 4.5 seconds The amount of finely roughened particles plated under the above conditions attached to the copper foil was 21.1 mg / dm ² .

Smooth layer plating conditions Plating bath composition Co (as metal): 8 g / l
Cu (as metal): 0.5 g / l
Ammonium sulfate: 40 g / l
Boric acid: 20 g / l
pH: 4.5
Plating conditions Temperature: 40 ° C
Current density: 3A / dm ²
Treatment time: 20 seconds The adhesion amounts of the smooth layer plated under the above conditions to the fine roughened particle layer were Co: 18.2 mg / dm ² and Cu: 0.61 mg / dm ² .

Plating conditions for the color bleed prevention treatment layer Plating bath composition Copper sulfate (as Cu metal): 1 g / l
Cobalt sulfate (as Co metal): 8g / l
Ammonium sulfate: 40 g / l
Boric acid: 20 g / l
pH :: 3.5
Plating conditions Temperature:: 40 ° C
Current density: 15 A / dm ²
Treatment time:: 4 seconds The composition of the fine roughened particle layer plated under the above conditions was analyzed. As a result, the actual composition was mg / dm ² foil; Cu: 4.2, Co: 8.3.

  The copper foil surface prepared in Examples 1 to 6 was subjected to rust prevention treatment and silane coupling agent treatment as necessary. The treatment method generally performed conventionally was applied to the rust prevention treatment and the silane coupling agent treatment method.

Comparative Examples 1 to 6
A black or brown treatment is applied to the copper foil (original foil) under the same conditions as in Examples 1, 2, 3, 4, 5, and 6, and a rust prevention treatment and a silane coupling agent treatment are performed directly without providing a color blur prevention treatment layer. Was given. This was designated as Comparative Examples 1, 2, 3, 4, 5, and 6.

Evaluation 1 Color bleeding The copper foils for electromagnetic wave shielding of Examples 1 to 6 and Comparative Examples 1 to 6 were bonded onto a polyethylene terephthalate film (thickness 75 μm). Adhesion was performed by applying a polyester adhesive containing a cross-linking agent to the copper foil surface to a thickness of 10 μm. Next, a grid pattern having a grid width of 20 μm and an eye size of 150 μm × 150 μm was printed on the copper foil by screen printing using a thermosetting ink. After the ink was cured by heating at 90 ° C. for 5 minutes, the metal layer of the portion not protected by the ink was removed with an aqueous ferric chloride solution, and then the ink was removed with a solvent. In this way, a laminated body that was an electromagnetic wave shield with an aperture ratio of 75% was prepared. Visible light was transmitted through this laminate, and the degree of color bleeding was observed with the naked eye. The results are shown in Table 1.

Evaluation 2 Flour-off characteristics Filter paper (Toyo filter paper No. 2) placed on a flat table with the black or brown treated surface of the copper foil prepared in Examples 1 to 6 and Comparative Examples 1 to 6 facing up. ), Put a weight (round with a bottom diameter of 15mmφ and weight 250g) on it, move the filter paper 15cm, and then check the presence or absence of copper powder on the filter paper, all the examples and comparative examples There was no occurrence of powder falling.

Evaluation 3 Pattern erosion by acid The lattice-patterned copper foil prepared in Evaluation 1 was further immersed in acid (5% sulfuric acid), and the erosion of the pattern portion was observed with a microscope. The results are shown in Table 1.

Evaluation 4 Electromagnetic wave shielding ability Using the copper foils of Examples 1 to 6 and Comparative Examples 1 to 6, the sheet resistance of the copper foil laminate for electromagnetic wave seeds prepared in Evaluation 1 was measured and found to be 0.07Ω / □ or more. Yes, it was an excellent electromagnetic shielding sheet.

Evaluation 5 When the transmittance of visible light was measured in the same manner as the transmittance, the average transmittance was 67% or more, indicating good performance.

なお、表１において、◎は特に優れている
○は優れている
△は実用的に問題なし
×は劣っている（実用化できない）
を示している。

In Table 1, ◎ is particularly excellent.
○ is excellent
△ is practically no problem
× is inferior (cannot be put into practical use)
Is shown.

As is apparent from Table 1, the color bleedability was evaluated to be more than excellent in the examples, whereas the comparative example was not suitable for practical use.
In addition, there are users who demand black as for the color tone, and there are users who demand brown, and they will be provided according to their respective requirements.
As for powder falling, both the examples and comparative examples were excellent, and results were difficult to attach.
There are some problems with pattern erosion by acid, but it has become a practical impediment.
As a result of the above, the copper foils of the examples can be provided as an electromagnetic wave shielding copper foil having excellent electromagnetic wave shielding ability, high transmittance, no powder falling off, and no light bleeding. An electromagnetic wave shield that can be suitably used for the PDP used can be provided.

Claims (13)

Black or brown treated layer made of fine roughened particles is provided on one side of the original foil made of copper foil or copper alloy foil, and the other side has a color tone lighter than the color tone of the black to brown treated layer provided on the one side A copper foil for electromagnetic wave shielding, which is provided with a black or brown color blur preventing treatment layer. Black or brown-treated layer is provided a fine roughening particles on one side of an original foil made copper foil or copper alloy foil, smooth layer is provided on the said black or brown treatment layer on the other surface, the A copper foil for electromagnetic wave shielding, wherein a black or brown bleed prevention layer having a lighter color tone than that of a black or brown treatment layer provided on one side is provided . 1 type or 2 types or more in the 1st fine particle group which the fine roughening particle which forms the said black thru | or brown process layer consists of copper, copper-cobalt, copper-nickel, cobalt-nickel, copper-cobalt-nickel The copper foil for electromagnetic wave shields of Claim 1 or 2 which laminated | stacked one or more layers of said composition. 1 is a copper alloy containing at least one of the second finely roughened particle groups in which the finely roughened particles forming the black or brown treated layer are made of Se, Sb, W, Te, Bi, Mo, Fe. Or the copper foil for electromagnetic wave shields of Claim 1 or 2 laminated | stacked in multiple layers. The black or brown treated layer is composed of one or more kinds of compositions of a first finely-roughened particle group consisting of copper, copper-cobalt, copper-nickel, cobalt-nickel, copper-cobalt-nickel. Second fine roughening made of a copper alloy containing at least one member of the second fine roughening particle group made of Se, Sb, W, Te, Bi, Mo, Fe on the first fine roughened particle layer. The copper foil for electromagnetic wave shielding according to claim 1, which is a fine roughened particle layer in which particle layers are laminated. The said smooth layer is copper foil for electromagnetic wave shields of Claim 2 which consists of 1 type, or 2 or more types of compositions among copper, cobalt, nickel, indium, or these alloys. The color bleed prevention treatment layer is formed of a first or second composition composed of one or more of the first finely-roughened particles consisting of copper, copper-cobalt, copper-nickel, cobalt-nickel, and copper-cobalt-nickel. 1st fine roughening particle layer, 2nd fine roughening particle layer which consists of a copper alloy containing at least any 1 type from the 2nd fine roughening particle group which consists of Se, Sb, W, Te, Bi, Mo, and Fe Or at least one smooth layer composed of one or more of copper, cobalt, nickel, indium or alloys thereof, and the color blur preventing treatment layer reflects light. The copper foil for electromagnetic wave shielding according to claim 1 or 2, wherein the copper foil is provided with a thickness sufficient to suppress the electromagnetic wave shielding. The copper foil for electromagnetic wave shielding according to claim 2, wherein the smooth layer is a Co alloy having a Cu content of 5% or less. 9. The copper foil for electromagnetic wave shielding according to claim 1, wherein the smooth layer surface has a surface roughness Rz of 3.5 μm or less. The copper foil for electromagnetic wave shielding according to claim 1 or 2, wherein the surface roughness Rz of the surface of the original foil made of the copper foil or copper alloy foil is a granular crystal having a size of 3 µm or less. The copper foil for electromagnetic wave shielding according to claim 1 or 2, wherein a rust prevention treatment is performed on the black or brown treatment layer and / or the color blur prevention treatment layer. 3. The copper foil for electromagnetic wave shielding according to claim 1, wherein a silane coupling agent treatment is performed on the black to brown treatment layer and / or the color bleed prevention treatment layer. The electromagnetic wave shielding body created with the copper foil for electromagnetic wave shielding in any one of Claims 1 thru | or 12.