JP2007332418A - Surface treated copper foil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide copper foil for a plasma display electromagnetic wave shielding filter having the characteristics that the color of a laminate face therein is a black system; there is no falling of fine roughened particles or the like; the laminate face has low roughness, and the laminate face has high smoothness which are particularly strongly required in the copper foil for a plasma display electromagnetic wave shielding filter. <P>SOLUTION: A fine roughened particle treatment layer of copper is applied to at least one side of copper foil, and also, ten point average roughness Rz is controlled to ≤2.0 μm. Then, the copper foil for a plasma display electromagnetic wave shielding filter having the characteristics of black color, low roughness and high smoothness in which surface system XYZ(Yxy)Y described in JIS Z8701 is ≤8.0, and also, specular gloss measured at Gs(60°) according to JIS Z8741 is ≥40, can be obtained. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a surface-treated copper foil, and more particularly to a copper foil used in an electromagnetic wave shielding filter, which is one of optical filters used in plasma display panels. The present invention relates to a surface-treated copper foil having no glossy particles, high glossiness and low surface roughness.

  In recent years, the spread of plasma display panels, which are image display displays having functions such as thinness, large screen, light weight, free viewing angle, moving image performance, and high contrast, has been spreading.

  However, since a large current flows through the plasma display to generate a magnetic field for discharging, the generation of electromagnetic waves is inevitable. As a result, the electromagnetic waves radiated from the front of the display are large and adversely affect peripheral devices and the human body. There is a need. An electromagnetic wave shielding filter is used for the purpose of suppressing this electromagnetic wave.

  Electromagnetic wave shielding filters include silver and other transparent conductive films, and metal fibers knitted in a mesh shape, etc. After copper foil is laminated to a polyester film (hereinafter referred to as PET) / adhesive, a mesh is formed by etching The way to do it is now mainstream. These electromagnetic wave shielding filters are required to have both light transmittance and electromagnetic wave shielding properties that are contrary to this, and the important characteristics required for the copper foil as a constituent material in this application are the following four points: Become.

1. The laminated surface of the copper foil is black. (Reason) To prevent reflection from outside light and increase the contrast to obtain a clear image.
2. No roughening particles fall off from the blackened surface (laminate surface), so-called powder-off phenomenon (reason) If there is powder-off, handling becomes difficult, and after etching, the roughened particles are formed in the adhesive layer. This may cause problems such as a remaining adhesive failure.
3. The laminated surface of the copper foil has low roughness (reason) The conductive mesh of the electromagnetic wave shielding filter generally has a width of 10 to 20 μm and a mesh interval of 200 to 300 μm. For this reason, in the case of a high-roughness copper foil, there is a problem that side etching during etching becomes large or roots remain, and it is difficult to obtain a highly accurate mesh.
4). The smoothness of the copper foil laminate surface (reason) Since the viewer sees the light transmitted through the part without the conductive mesh of the electromagnetic wave shielding filter, the transparency of the PET / adhesive after etching is high. The image becomes clearer.
Since the surface shape of the PET / adhesive after etching is the shape obtained by transferring the copper foil laminate surface as it is, if the copper foil laminate surface is rough, irregularities transferred from the copper foil to the adhesive layer are created, and haze (cloudy) Because the transparency of PET / adhesive deteriorates.

  As a copper foil for use in plasma display electromagnetic wave shielding filters, a copper foil satisfying the above characteristics has been demanded, and development of a copper foil having a black and flat surface has been awaited.

  As a surface treatment method for a copper foil for an electromagnetic wave shielding filter for plasma display, for example (Patent Document 1), an alloy plating layer made of tin-nickel-molybdenum is formed after copper dendritic roughening and copper cover plating. Although the method of applying is proposed, the specular glossiness is low and the transparency of the PET / adhesive after etching is deteriorated.

  (Patent Document 2) and (Patent Document 3) propose a treatment method using a cobalt sulfate bath, but similarly, the mirror gloss is low and the transparency of the PET / adhesive after etching deteriorates. In 3), the reflectance Y is also high, and the appearance blackness is low, which is problematic.

  (Patent Document 4) proposes a method in which a copper foil having an Rz of 3.0 μm or less is subjected to a copper roughening treatment, followed by a treatment comprising copper-cobalt, and further a smooth plating of cobalt. It has a disadvantage that the degree of light is low, the reflectivity Y is high, the light transmittance and the contrast for preventing reflection of external light are both low, the powder falls off, and a good image cannot be obtained.

Japanese Patent Laid-Open No. 2003-201597 JP 2005-139544 JP JP 2005-163170 A JP 2005-150155 A

  The problem to be solved by the present invention has a feature that the laminated surface of the copper foil has a black appearance, the laminated surface of the copper foil has low roughness and high smoothness, and does not drop off roughened particles. It is providing the copper foil for said plasma display electromagnetic wave shielding filters.

  As a result of studying various surface treatments in order to achieve the above object, it has been found that it can be achieved by applying the following surface treatment to the copper foil.

  A copper roughened particle treated layer having a glossiness Gs (60 °) measured based on JISZ8741 of 40 or more and Y of color system XYZ (Yxy) described in JISZ8701 is 8.0 or less. On at least one side. Further, the ten-point average roughness Rz after forming the copper fine-roughened particle treated layer is 2.0 μm or less. A rust prevention treatment layer containing at least one of nickel, molybdenum, tungsten, cobalt, phosphorus, copper, germanium, chromium, and zinc may be provided on the copper fine-roughening particle treatment layer. A silane coupling agent layer may be provided thereon. Further, a cobalt or nickel fine roughened particle layer may be provided on the copper finely roughened particle treated layer, or the copper fine roughened particle treated layer may be a copper finely roughened particle treated layer containing iron.

  The effect of the present invention described above is that the surface treatment of the above-described form is performed on at least one surface of the copper foil, so that the Y of the color system XYZ (Yxy) is lowered and the reflection from external light is suppressed to a very low level. PET / adhesive after etching with high glossiness and high-accuracy mesh pattern with good etching properties due to low roughness. It is a copper foil suitable for a plasma display electromagnetic wave shielding filter having a characteristic that a clear image can be obtained because of its high transparency and low haze.

  The present invention is described in detail below.

  First, the copper foil to be used may be either a rolled copper foil or an electrolytic copper foil, but in this application, the rough surface roughness of the copper foil is premised on a low roughness. In consideration of an increase in roughness of the rough surface, it is preferable to use an untreated copper foil having a roughness Rz of 1.7 μm or less.

  Even if untreated copper foil with a large roughness is used, blackening by fine copper roughening particle processing is possible, but the etching property, PET / adhesive transparency after etching is reduced, etc. This is not preferable because it may cause the above problems. The foil thickness of the copper foil is 5 to 35 μm, more preferably 6 to 18 μm.

  The copper fine-roughened particle-treated layer of the present invention is formed, for example, by dipping in an aqueous solution containing copper ions and diethylenetriaminepentaacetic acid and cathodic electrolysis. Although the example of the bath composition and electrolysis conditions which form a copper fine roughening particle process layer is given to the following, it does not specifically limit to this.

(Bath composition)
Copper sulfate pentahydrate 10-100g / L (particularly preferably 25-60g / L)
Diethylenetriaminepentaacetic acid pentasodium 10-300 g / L (particularly preferably 30-60 g / L)
pH 2.5-13.0 (particularly preferably 3.5-6.0)
pH adjusted with sulfuric acid (electrolysis conditions)
Bath temperature 20-60 ° C (particularly preferably 25-45 ° C)
Current density 1-10A / dm ² (particularly preferably 2-4A / dm ² )
Electricity 10 ~ 500A ・ sec / dm ² (Preferably 30 ~ 100A ・ sec / dm ² )

  The copper fine-roughened particle-treated layer of the present invention exhibits a black appearance with no processing unevenness. In addition, unlike the conventional roughening treatment method, the fine roughening particle treatment of the present invention has an extremely low increase in the roughness of the rough surface, so that it is possible to reduce the roughness of the rough surface after the treatment, As a result, it is possible to obtain low Rz and high glossiness suitable as a copper foil for an electromagnetic wave shielding filter for a plasma display panel.

  Furthermore, the appearance of a further black color tone can be obtained by applying a fine roughening particle layer of cobalt and nickel after the formation of a copper fine roughening particle treatment layer.

  Moreover, the appearance of a further black color tone can be obtained by forming a fine roughening particle treatment layer of copper containing iron, and a copper foil more suitable as a copper foil for an electromagnetic wave shielding filter for a plasma display panel can be obtained. .

  Cobalt layer containing at least one of molybdenum or tungsten as disclosed in JP-B-2-24037 after the copper fine-roughening particle treatment of the present invention, molybdenum or tungsten as disclosed in JP-A-2003-171781 The nickel-phosphorus layer, cobalt or nickel layer containing germanium as disclosed in JP-A-2003-298229, other heat-resistant / rust-proof layer, chromate film layer, and silane coupling agent layer are further improved. Characteristics can be obtained.

  When a heat-resistant / rust-proof layer is applied, the heat discoloration resistance and oxidation resistance from the heat history received during the production of an electromagnetic wave shield filter is improved. Examples of bath composition and electrolysis conditions for forming a heat-resistant / rust-proof layer are given.

(Cobalt-molybdenum layer)
Cobalt sulfate heptahydrate 10-100 g / L (particularly preferably 20-50 g / L)
Disodium molybdate dihydrate 1-80 g / L (particularly preferably 5-50 g / L)
Trisodium citrate dihydrate 5-100g / L (particularly preferably 20-60g / L)
pH 4.0 to 10.0 (particularly preferably 5.0 to 7.0)

(Nickel-phosphorus-tungsten layer)
Nickel sulfate hexahydrate 10-100g / L (particularly preferably 20-50g / L)
Sodium hypophosphite monohydrate 0.1-10 g / L (particularly preferably 0.5-5 g / L)
Sodium tungstate dihydrate 0.1-20 g / L (particularly preferably 0.5-10 g / L)
Sodium acetate trihydrate 2-20g / L (particularly preferably 3-15g / L)
pH 3.0-5.5 (particularly preferably 3.5-5.0)

(Cobalt-nickel-germanium layer)
Cobalt sulfate heptahydrate 10-100 g / L (particularly preferably 20-50 g / L)
Nickel sulfate hexahydrate 10-100 g / L (particularly preferably 20-50 g / L) CrO ₃
Germanium dioxide 0.1-10g / L (particularly preferably 0.3-3g / L)
Trisodium citrate dihydrate 5-100g / L (particularly preferably 20-60g / L)
pH 3.0 to 10.0 (particularly preferably 4.0 to 7.0)

  Further, sodium sulfate may be added for the purpose of imparting conductivity.

(Electrolysis conditions)
Bath temperature 20-50 ° C (particularly preferably 25-40 ° C)
Current density 0.1 to 10A / dm ² (particularly preferably 10 to 30A · sec / dm ² )
Amount of electricity 5 to 40 A · sec / dm ² (particularly preferably 10 to 30 A · sec / dm ² )

When a chromate film layer is applied, characteristics such as oxidation resistance are improved. The bath for forming the chromate film layer may be a well-known bath, for example, any one having hexavalent chromium such as chromic acid, sodium dichromate, potassium dichromate and the like. In addition, the precipitation form of chromium after the chromate film layer is formed is a state in which Cr (OH) ₃ and Cr ₂ O ₃ coexist, and there is no hexavalent chromium that adversely affects the human body, and it is deposited in the form of trivalent chromium. .

Examples of the bath composition and electrolysis conditions for forming the chromate film layer are given.
Sodium dichromate 10g / L
Bath temperature 30 ℃
pH 4.2
Current density 10A / dm ²
Electrolysis time 5 seconds

  In addition, an alkaline zinc chromate solution containing zinc ions and hexavalent chromium ions described in Japanese Patent Publication No. 58-15950 may be used. By using this chromic acid solution, a chromate film layer from a single acid solution of chromium is used. Can also improve oxidation resistance.

  When a silane coupling agent layer is applied, properties such as oxidation resistance, adhesive strength, and adhesive strength after severe testing are improved. There are various types of silane coupling agents such as epoxy group, amino group, mercapto group, vinyl group, methacryloxy group, styryl group, etc., but each has different characteristics, and it is compatible with the base material, so it is necessary to select it. is there.

Examples of the bath for applying the silane coupling agent layer include the following composition and conditions.
[3- (2-Aminoethyl) aminopropyl] trimethoxysilane 2mL / L
Bath temperature 30 ℃
Immersion time 15 seconds

  The embodiments of the present invention described above will be described in detail below. However, the present invention is not particularly limited to the following examples.

Example 1.

First, a 12 μm electrolytic copper foil prepared by the manufacturing method described in JP-A-2004-263289 was prepared.
The copper foil is glossy on any surface in an untreated state, and the Rz (ten-point average roughness) of the plating-finished surface generally called M surface, rough surface, mat surface, etc. is 0.67 μm, Mirror gloss Gs at °
687 (Gs at 85 ° was 141). The Rz of the plating starting surface called S surface, smooth surface, gloss surface, shiny surface, drum surface, etc. was 1.26 μm. Hereinafter, the plating end surface of the electrolytic copper foil is referred to as a rough surface, and the plating start surface is referred to as a smooth surface.

  First, the untreated foil was immersed in a sulfuric acid solution having a sulfuric acid concentration of 100 g / L and a bath temperature of 20 ° C. for 60 seconds to remove the oxide layer on the surface. Next, cathodic electrolysis was carried out under the bath composition and electrolysis conditions described below to form a copper fine-roughened particle-treated layer on the rough surface of the untreated foil.

(Bath composition)
Copper sulfate pentahydrate 35g / L
Diethylenetriaminepentaacetic acid pentasodium 42g / L
pH 4.5
(Electrolysis conditions)
Bath temperature 35 ℃
Current density 2A / dm ²
Electrolysis time 10 seconds

Further, it was immersed in a rust preventive solution having the following bath composition for 10 seconds.
(Bath composition)
Sodium dichromate 10g / L
Bath temperature 20 ℃
pH 4.2
Thereafter, it was washed with water and dried.

Example 2

  The same treatment as in Example 1 was performed except that the electrolysis time for forming the copper fine-roughened particle treatment layer was 20 seconds.

Example 3

  The same treatment as in Example 1 was performed except that the electrolysis time for forming the copper fine-roughened particle treatment layer was 30 seconds.

Example 4

  The same treatment as in Example 1 was performed except that the electrolysis time for forming the copper fine-roughened particle treatment layer was 40 seconds.

Example 5 FIG.

The same treatment as in Example 1 was performed except that the current density at the time of forming the copper fine-roughened particle treatment layer was 3 A / dm ² and the electrolysis time was 20 seconds.

Example 6

The same treatment as in Example 1 was performed, except that the current density during the formation of the copper fine-roughened particle treatment layer was 4 A / dm ² and the electrolysis time was 20 seconds.

Example 7

The untreated copper foil used in Example 1 was immersed in a sulfuric acid solution having a sulfuric acid concentration of 100 g / L and a bath temperature of 20 ° C. for 60 seconds to remove the oxide layer on the surface. Thereafter, the current density when forming the copper fine-roughened particle treatment layer is 2 A / dm ² , and the process for forming the copper fine-roughened particle treatment layer under the same conditions as in Example 1 except that the electrolysis time is 20 seconds. Went. Thereafter, rust prevention treatment was performed with an alkaline zinc chromate solution having the following bath composition and electrolytic conditions.

(Bath composition)
Sodium dichromate 10g / L
Zinc ion 0.5g / L
Sodium hydroxide 35g / L
(Electrolysis conditions)
Current density 2A / dm ²
Electrolysis time 10 seconds

Example 8 FIG.

After performing the treatment of Example 7, it was immersed in a silane coupling agent having the following composition and conditions for 10 seconds.
[3- (2-Aminoethyl) aminopropyl] trimethoxysilane 10mL / L
Bath temperature 20 ℃

Example 9

The untreated copper foil used in Example 1 was immersed in a sulfuric acid solution having a sulfuric acid concentration of 100 g / L and a bath temperature of 20 ° C. for 60 seconds to remove the oxide layer on the surface. Thereafter, the current density when forming the copper fine-roughened particle treatment layer is 2 A / dm ² , and the process for forming the copper fine-roughened particle treatment layer under the same conditions as in Example 1 except that the electrolysis time is 20 seconds. Went. Thereafter, heat treatment and rust prevention treatment were performed under the bath composition and electrolysis conditions described below.

(Bath composition)
Nickel sulfate hexahydrate 30g / L
Sodium hypophosphite monohydrate 2g / L
Sodium tungstate dihydrate 3g / L
Sodium acetate trihydrate 10g / L
pH 4.5
(Electrolysis conditions)
Bath temperature 32 ℃
Current density 1.5A / dm ²
Electrolysis time 3 seconds Further, the film was immersed in a rust preventive liquid having the bath composition of Example 1 for 10 seconds, then washed with water and dried.

Example 10

The untreated copper foil used in Example 1 was immersed in a sulfuric acid solution having a sulfuric acid concentration of 100 g / L and a bath temperature of 20 ° C. for 60 seconds to remove the oxide layer on the surface. Thereafter, the current density when forming the copper fine-roughened particle treatment layer is 2 A / dm ² , and the process for forming the copper fine-roughened particle treatment layer under the same conditions as in Example 1 except that the electrolysis time is 20 seconds. Went. Thereafter, heat treatment and rust prevention treatment were performed under the bath composition and electrolysis conditions described below.

(Bath composition)
Cobalt sulfate heptahydrate 38g / L
Disodium molybdate dihydrate 23g / L
Trisodium citrate dihydrate 45g / L
Sodium sulfate 80g / L
pH 5.5
(Electrolysis conditions)
Bath temperature 30 ℃
Current density 2A / dm ²
Electrolysis time 3 seconds Further, the film was immersed in a rust preventive liquid having the bath composition of Example 1 for 10 seconds, then washed with water and dried.

Example 11

  A 12 μm electrolytic copper foil prepared by the manufacturing method described in JP-A-2004-263289 was prepared. However, an untreated copper foil having a slightly rough ten-point average roughness Rz on the rough surface as compared with Examples 1 to 10 was used. Rz of the rough surface of the untreated copper foil was 1.52 μm, and the specular glossiness Gs at 60 ° was 608 (Gs at 85 ° was 140). Rz of the smooth surface was 1.73 μm. The treatment was performed under exactly the same conditions as in Example 2 except that the rough surface roughness of the untreated copper foil was different.

Example 12

  A copper fine-roughened particle-treated layer containing iron was formed, and the characteristics were confirmed. As the untreated copper foil, the same foil as in Example 1 was used, and the surface oxide layer was removed by immersing in a sulfuric acid solution having a sulfuric acid concentration of 100 g / L and a bath temperature of 20 ° C. for 60 seconds. Next, a copper fine-roughened particle treatment layer containing iron was formed and processed under the bath composition and electrolysis conditions described below.

(Bath composition)
Copper sulfate pentahydrate 35g / L
Ferric sulfate n hydrate 10g / L
Diethylenetriaminepentaacetic acid pentasodium 42g / L
pH 4.5
(Electrolysis conditions)
Bath temperature 35 ℃
Current density 2A / dm ²
Electrolysis time 20 seconds Further, the film was immersed in a rust preventive solution having the bath composition of Example 1 for 10 seconds, then washed with water and dried.

Example 13

  After forming the copper fine-roughened particle treatment layer, a cobalt fine-roughened particle treatment layer was formed, and the characteristics were confirmed. The untreated copper foil was the same as that used in Example 1. The surface oxide layer is removed by dipping in a sulfuric acid solution with a sulfuric acid concentration of 100 g / L and a bath temperature of 20 ° C. for 60 seconds. Next, a copper roughened particle treatment layer is formed with the bath composition and electrolytic conditions shown below. I let you.

(Bath composition)
Copper sulfate pentahydrate 35g / L
Diethylenetriaminepentaacetic acid pentasodium 42g / L
pH 4.5
(Electrolysis conditions)
Bath temperature 35 ℃
Current density 2A / dm ²
Electrolysis time 20 seconds Further, a cobalt fine roughening layer was formed under the following conditions.

(Bath composition)
Cobalt sulfate heptahydrate 10g / L
pH 5.0
(Electrolysis conditions)
Bath temperature 30 ℃
Current density 2A / dm ²
Electrolysis time: 5 seconds Thereafter, it was immersed in a rust preventive liquid having the bath composition of Example 1 for 10 seconds, washed with water and dried.

Comparative Example 1

  The untreated copper foil used in Example 1 was immersed in a sulfuric acid solution having a sulfuric acid concentration of 100 g / L and a bath temperature of 20 ° C. for 60 seconds to remove the oxide layer on the surface. Next, a cobalt sulfate plating layer was formed on the smooth surface side of the untreated copper foil by cathodic electrolysis under the following bath composition and electrolysis conditions.

(Bath composition)
Cobalt sulfate heptahydrate 10g / L
pH 5.0
(Electrolysis conditions)
Bath temperature 30 ℃
Current density 2A / dm ²
Electrolysis time 3 seconds Further, the film was immersed in a rust preventive liquid having the bath composition of Example 1 for 10 seconds, then washed with water and dried.

Comparative Example 2

The same treatment as in Comparative Example 1 was performed except that the current density was 2 A / dm ² and the electrolysis time was 8 seconds in a cobalt sulfate plating bath.

Comparative Example 3

  The untreated copper foil used in Example 1 was immersed in a sulfuric acid solution having a sulfuric acid concentration of 100 g / L and a bath temperature of 20 ° C. for 60 seconds to remove the oxidized layer on the surface. Next, the bath composition and electrolytic conditions shown below were used. By cathodic electrolysis, a roughened layer was formed on the rough side of the untreated copper foil.

(Bath composition)
Copper sulfate pentahydrate 50g / L
Zinc sulfate heptahydrate 58g / L
Sodium molybdate dihydrate 2g / L
Anhydrous sodium sulfate 14g / L
pH 2.0
(Electrolysis conditions)
Bath temperature 30 ℃
Current density 6A / dm ²
Electrolysis time 2 seconds Cathodic electrolysis was then carried out under the bath composition and electrolysis conditions shown below to form a cover plating layer.

(Bath composition)
Copper sulfate pentahydrate 135g / L
Sulfuric acid 100g / L
(Electrolysis conditions)
Bath temperature 40 ℃
Current density 3A / dm ²
Electrolysis time 8 seconds After the cover plating layer was formed, the plate was washed with water, and then cathodic electrolysis was performed under the bath composition and electrolysis conditions shown below to form an alloy plating layer.

(Bath composition)
Nickel sulfate hexahydrate 13g / L
Tin pyrophosphate 3g / L
Sodium molybdate dihydrate 12g / L
Potassium pyrophosphate 33g / L
Glycine 4g / L
pH 8.0
(Electrolysis conditions)
Bath temperature 30 ℃
Current density 3A / dm ²
Electrolysis time: 8 seconds Further, it was immersed in a rust preventive solution having the bath composition of Example 1 for 10 seconds, then washed with water and dried.

Comparative Example 4

  An untreated electrolytic copper foil having a ten-point average roughness Rz of the rough surface of 2.65 μm, a specular gloss Gs of 2 at 60 °, and a smooth surface Rz of 1.61 μm was prepared. The untreated copper foil is immersed in a sulfuric acid solution having a sulfuric acid concentration of 100 g / L and a bath temperature of 20 ° C. for 60 seconds to remove the oxidized layer on the surface, and then cathodically electrolyzed with the following bath composition and electrolytic conditions. Then, a copper roughened layer was formed on the rough side of the untreated foil.

(Bath composition)
Copper sulfate pentahydrate 250g / L
Sulfuric acid 120g / L
(Electrolysis conditions)
Bath temperature 40 ℃
Current density 65A / dm ²
Electrolysis time 1.2 seconds Next, a roughening treatment layer was formed on the rough side of the copper foil by cathodic electrolysis under the following bath composition and electrolysis conditions.

(Bath composition)
Copper sulfate pentahydrate 3.9g / L
Cobalt sulfate heptahydrate 38.1g / L
Ammonium sulfate 40g / L
Boric acid 20g / L
pH 3.8
(Electrolysis conditions)
Bath temperature 40 ℃
Current density 15A / dm ²
Electrolysis time 3 seconds Further, a smooth plating layer made of cobalt was formed on the rough surface side of the copper foil by cathodic electrolysis under the bath composition and electrolysis conditions described below.

(Bath composition)
Cobalt sulfate heptahydrate 47.6g / L
Ammonium sulfate 40g / L
Boric acid 20g / L
pH 2.5
(Electrolysis conditions)
Bath temperature 40 ℃
Current density 3A / dm ²
Electrolysis time 30 seconds Further, the electrolysis time was immersed in a rust preventive liquid having the bath composition of Example 1 for 10 seconds, then washed with water and dried.

Comparative Example 5

  The same copper foil as in Comparative Example 4 was prepared. This copper foil was processed under exactly the same processing conditions as in Example 2.

  Further, in each of Examples 1 to 12 and Comparative Examples 1 to 5, water washing was provided between the respective steps for the purpose of preventing the solution of the previous step from being brought into the subsequent step.

  Table 1 shows the results of measuring Y of the color system XYZ (Yxy), specular glossiness Gs (60 °), and rough surface roughness Rz of the copper foil subjected to the surface treatment of Examples 1 to 12 and Comparative Examples 1 to 5. Shown in 1. Y is measured using Konica Minolta's spectrophotometer CM-508d based on JIS Z8701, and specular gloss Gs (60 °) is Konica Minolta's gloss meter multi gloss based on JIS Z8741. 268 type was used, and the roughness Rz was measured using a surf coder SE1700α manufactured by Kosaka Laboratory based on JIS B0601.

  As shown in Table 1, the surface-treated copper foil having the copper fine-roughened particle-treated layer of the present invention of Examples 1 to 13 or the copper fine-roughened particle-treated layer containing iron is XYZ described in JIS Z8701. It can be seen that Y of (Yxy) is 8.0 or less and has a color close to black. It can also be seen that the rough surface roughness Rz is a low roughness of 2.0 or less and the specular gloss Gs (60 °) is 40 or more.

  When a plasma display electromagnetic wave shielding filter is produced using the copper foil of this example, reflection from outside light can be suppressed low, high contrast can be obtained, and mesh formation with higher etching accuracy is possible. Further, since the PET / adhesive after etching has high transparency, it becomes a good electromagnetic wave shielding filter capable of obtaining a clear image. However, only Example 12 shows a slight powder fall.

  On the other hand, the treatment method using a cobalt sulfate bath referring to (Patent Document 2) and (Patent Document 3) as in Comparative Examples 1 and 2 has a low specular gloss Gs (60 °), and the PET / adhesive after etching. In Comparative Example 1, Y is more than 10, which is problematic in terms of black appearance.

  In Comparative Example 3, referring to (Patent Document 1), an alloy composed of tin-nickel-molybdenum after copper dendritic roughening treatment, cover plating for expressing the roughening treatment and adhesion of copper foil is performed. An attempt was made to apply a plating layer, but the specular gloss Gs (60 °) is low, and the transparency of the PET / adhesive after etching is poor. Slightly falling off is also seen.

  Referring to (Patent Document 4) as in Comparative Example 4, a copper foil having an Rz of 3.0 μm or less was subjected to a roughening treatment made of copper, then a treatment made of copper-cobalt, and further a smooth plating of cobalt. It can be seen that the method used has the disadvantages that the specular gloss Gs (60 °) is low, the Y is also high, many powders are lost, and a good image cannot be obtained.

  As in Comparative Example 5, in the method of performing the treatment for forming the copper roughened particle treatment layer of the present invention using a rough untreated copper foil of Rz 2.65 μm, the specular gloss Gs (60 °) Is extremely low, the transparency of the PET / adhesive after etching is deteriorated, and there is a tendency that the amount of powder falling increases as compared with an example having a low roughness Rz. From this, it can be seen that if the roughness of the rough surface is too rough, the characteristics required for the copper foil for plasma display electromagnetic wave shielding filter cannot be obtained, and a good electromagnetic wave shielding filter cannot be obtained.

  In the present invention, a copper fine-roughened particle-treated layer is applied to at least one surface of a copper foil, and the 10-point average roughness Rz is adjusted to 2.0 μm or less, whereby the color system XYZ described in JIS Z8701 ( Yxy) is a copper foil for electromagnetic wave shielding filter for plasma display having Y of 8.0 or less and specular gloss Gs (60 °) measured based on JIS Z8741 of 40 or more, and using this copper foil, an electromagnetic shielding filter , The reflection from outside light can be suppressed to a very low level, so that a clear image can be obtained, and since the etching property is good, a highly accurate mesh can be obtained, and the glossiness is high. Since the PET / adhesive after etching is highly transparent and the haze (cloudiness) is low, a clear image can be obtained. Moreover, there is a possibility of being used for an electronic substrate material that requires a copper foil having a low roughness and a black color.

Example 2 Electron micrograph of copper foil treated surface side of the present invention Comparative example 3 Copper foil treated surface side electron micrograph

Claims (8)

  At least one surface of the copper foil has a copper roughened particle treatment layer, the gloss Gs (60 °) described in JISZ8741 on that surface is 40 or more, and the color system XYZ described in JISZ8701 ( A surface-treated copper foil characterized in that Y of Yxy) is 8.0 or less.   2. The surface-treated copper foil according to claim 1, which is used for an electromagnetic wave shielding filter for a PDP (plasma display panel).   3. The surface-treated copper foil according to claim 1, wherein the ten-point average roughness Rz after forming the copper fine-roughened particle-treated layer is 2.0 μm or less.   4. A heat-resistant treatment layer containing at least one kind of nickel, molybdenum, tungsten, cobalt, phosphorus, copper, and germanium is provided on the copper roughening particle treatment layer. Surface treated copper foil.   A heat-resistant treatment layer containing at least one of nickel, molybdenum, tungsten, cobalt, phosphorus, copper, and germanium is provided on the copper fine-grained particle treatment layer, and at least one of chromium and zinc is provided on the heat-resistant treatment layer. 5. The surface-treated copper foil according to claim 1, further comprising a rust-proofing layer containing   A heat-resistant treatment layer containing at least one of nickel, molybdenum, tungsten, cobalt, phosphorus, copper, and germanium is provided on the copper fine-grained particle treatment layer, and at least one of chromium and zinc is provided on the heat-resistant treatment layer. 6. The surface-treated copper foil according to any one of claims 1 to 5, wherein a rust-proofing layer containing is provided, and a silane coupling agent layer is further provided on the heat-resistant / rust-proofing layer.   7. The surface-treated copper foil according to claim 1, wherein the fine roughened particle treated layer is copper containing iron. 8. The surface-treated copper foil according to claim 1, wherein a cobalt or nickel fine-roughened particle treated layer is provided on the copper finely-roughened particle treated layer.

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