JP4575719B2 - Surface-treated copper foil having a browned surface, a method for producing the surface-treated copper foil, and an electromagnetic shielding conductive mesh for a front panel of a plasma display using the surface-treated copper foil - Google Patents

Description

  The present invention relates to a surface-treated copper foil having a browned surface, a method for producing the surface-treated copper foil, and an electromagnetic wave shielding conductive mesh for a front panel of a plasma display using the surface-treated copper foil.

  In the course of progress, the conductive mesh for shielding the plasma display panel has changed from a metalized fiber fabric to a conductive mesh. Several methods have been established for producing this conductive mesh. One of them is to manufacture by using a photolithographic etching method by laminating and bonding a surface-treated copper foil to a PET film. The other is a conductive mesh of a single surface-treated copper foil obtained by etching a surface-treated copper foil together with a supporting base material by a photolithographic etching method, and then peeling the supporting base material.

  Furthermore, in order to compensate for the decrease in luminance due to the decrease in the voltage, the circuit width of the conductive mesh has been increased in order to compensate for the decrease in the luminance due to the decrease in the voltage. Attempts have been made to reduce the coverage of the front glass panel by thinning the conductive mesh. Therefore, the thickness of the conductive mesh has been reduced to facilitate the etching process. One of them is to form a seed layer, which is the seed of electroplating, on the PET film by sputtering vapor deposition, and then to form a thin copper layer by electrolytic copper plating, etc., and to refine the mesh line width by photolithographic etching Conductive meshes have been manufactured.

  Regardless of which method is used to produce the conductive mesh, the conductive mesh itself is built into the front panel and visible from the surface through the front glass, so the surface processed into the conductive mesh. One side of the treated copper foil is treated from a brown color to a black dark state so that the brightness of transmitted light is enhanced. Conventionally, the blackening process etc. which are the techniques of a multilayer printed wiring board for improving the adhesiveness of an inner circuit and a resin layer, etc. have been diverted to this process.

Technical Trends of PDP Materials Hitachi Chemical Technical Report No. 33 (1999-7) Japanese Patent Laid-Open No. 11-186785 JP 2000-31588 A

  However, the above blackening process has a serious problem. That is, when a large amount of black oxide of copper is applied to the surface of the copper foil, a good blackened surface can be obtained. However, the copper black oxide formed on the surface of the copper foil is more likely to fall off from the blackened surface as the amount of adhesion increases, and the so-called powder-off phenomenon tends to occur.

  Factors that cause the falling black oxide to mix into the useless parts or to disperse in the transparent adhesive layer during the clearing process to integrate with the front panel glass. It can be a friend.

On the other hand, general black nickel plating, nickel sulfide plating, cobalt plating, and the like have been studied as blackening treatments that can form a good blackened surface without powder fall off like blackening treatments. There has been a problem that etching cannot be performed from the blackened surface side by a normal copper etching process. In particular, the surface-treated copper foil having a blackened surface on which nickel is deposited in a rich amount of about 1000 mg / m ² cannot solve the problem of powder falling, and is expensive because it uses a large amount of expensive nickel. It was. Scanning electron microscope images of the blackened surface of the surface-treated copper foil are shown in FIGS.

  In particular, a copper foil provided with a black plating film of cobalt currently on the market has a problem that it is difficult to etch the cobalt layer using a copper etchant.

  On the other hand, surface-treated copper foil with a simply blackened surface has been required in the past. However, the manufacturing technology of plasma display panels has matured, and with the advancement of manufacturing technology and management, the electromagnetic shielding conductive mesh has been improved. A high level of blackness is not necessary, but rather an electromagnetic shielding conductive mesh that is inexpensive, easier to etch, and stable in light transmission has come to be desired.

  And considering the low price requirement and the fact that etching is easy, it is considered that the surface of the surface-treated copper foil is not blackened, but the amount of cobalt adhesion is reduced and the product is supplied in a brownish state. I came. However, the disadvantage of the surface-treated copper foil having a brownish brown surface is that the brownish brown surface is not uniform in color and uneven. That is, the brown color treatment in the same plane has not been made uniform. Strictly speaking, when etching processing is attempted from the brown color surface, it causes the variation in the cross-sectional shape of the mesh obtained by etching. It was. Moreover, the brown surface was in a matte state, and it was easily damaged by merely rubbing the surface. FIG. 12 shows a scanning electron microscope image of the surface-treated copper foil having such a conventional brown surface.

  Therefore, in the market, a surface-treated copper foil having a browning treatment layer having a uniform brown color and easily etched by a normal copper etching process and having a smooth cobalt plating film with little frictional damage, and its A conductive mesh made of such a surface-treated copper foil has been desired.

  Therefore, as a result of earnest research, the present inventors have used a surface-treated copper foil as shown below, and even the surface-treated copper foil having a brown-cobalt cobalt plating layer has an extremely uniform brown surface. It is thought that it is possible to obtain a high-quality electromagnetic shielding conductive mesh for the front panel of a plasma display, which is excellent in scratch resistance with no unevenness and can be easily etched with a copper etchant. It is.

<Surface treated copper foil with browned surface>
The surface-treated copper foil provided with the browning treatment surface according to the present invention has no rust-proofing layer (hereinafter referred to as “first surface-treated copper foil”) and has a rust-proofing layer (hereinafter referred to as “first rust-treated copper foil”). And "second surface-treated copper foil"). Therefore, the antirust treatment layer is not essential, but is necessary for ensuring long-term storage as a surface-treated copper foil. Hereinafter, the surface-treated copper foil according to the present invention will be described.

1st surface-treated copper foil: The 1st surface-treated copper foil which concerns on this invention is "surface-treated copper foil provided with the browning treatment surface, Comprising: The said browning treatment surface is weight thickness 90mg / m < ² > -160mg. / M ² cobalt sulfate plating layer, the surface having a browning treatment surface characterized in that the browning treatment surface has a cross-sectional height of 150 nm or less and the a value in the Lab color system is 4.0 or less Treated copper foil. " FIG. 1 schematically shows the cross-sectional layer structure of the surface-treated copper foil 1a.

  In FIG. 1, as the roughening treatment layer 2, a surface treatment copper foil 1 a in a state where fine copper particles 3 are attached to one side of a copper foil layer 7 is schematically described as an example. However, the copper foil used at this time may be roughened or may not be roughened. FIG. 2 schematically shows the surface-treated copper foil 1b when the roughening treatment is omitted. In addition, any surface may be used on the rough surface side or the gloss surface side of the electrolytic copper foil. Considering the case where the roughening treatment layer 2 composed of the fine copper grains 3 is provided on one side, the roughening treatment layer 2 is usually formed for the purpose of improving the adhesion to the substrate. Then, it has a fine uneven shape, and it absorbs the light hitting the surface and plays an auxiliary role to make it a dark brown surface. Therefore, the method for forming the roughened layer 2 can employ a method of forming fine copper particles as described above, a method of attaching fine copper oxide, or the like. The more uneven, the better. For the copper foil layer 7, an electrolytic copper foil obtained by an electrolytic method and a rolled copper foil obtained by a rolling method are mainly used.

The cobalt sulfate plating layer 4 is provided on the surface of the copper foil layer 7 (corresponding to the surface of the roughening treatment layer 2 in FIG. 1). The cobalt sulfate plating layer 4 here is used to mean a layer formed by a plating method using a cobalt sulfate solution. The cobalt sulfate plating layer 4 is, by those of the manufacturing method was employed wt thickness 90mg ^/ m ² ~160mg / m 2 to be described later, excellent in solubility in copper etching solution, and, enough brown of It becomes possible. The cobalt layer of the copper foil provided with the black plating film using the conventional cobalt layer has a weight thickness of around 1000 mg / m ² and is very thick and has a different quality in terms of solubility of the plating layer. . As a result, because of the thickness, the dissolution rate by the copper etching solution slows down, and the element itself called cobalt accumulates in the copper etching solution at a high concentration, which causes the titer of the etching solution to decrease. . In addition, the converted weight in this invention is converted into cobalt weight. The converted weight is obtained by dissolving the surface-treated copper foil in an acid solution, obtaining the amount of cobalt per unit area by plasma emission spectroscopy or the like, and converting it to the weight per 1 m ^{2 of the} surface-treated copper foil.

  In addition, the feature of the surface-treated copper foil according to the present invention is that the surface shape of the browning surface is not very rough, and the cross-sectional height of the browning surface is 150 nm or less. That is, it can be said that the surface is a browning treatment surface that is extremely smooth and glossy. However, in order to avoid misunderstanding, it is natural that there is variation within the range of the normal manufacturing process, and the cross-sectional height at all positions is not necessarily 150 nm or less, Of course, there may be a cross-sectional height of more than 150 nm to reflect the variation in the manufacturing process. In order to measure the cross-sectional height of the browning surface 2 of the surface-treated copper foil 1 according to the present invention, an observation image obtained by cross-sectional observation using a focused ion beam processing observation apparatus is shown in FIG. FIG. 3 shows the electrolytic copper foil with a browned surface formed on the glossy surface. This observation image is observed from a direction having an angle of 60 ° with respect to the surface to be observed.

  As can be seen from FIG. 3, it is clear that the cross section of the browning surface has certain irregularities, and in order to monitor such irregularities, a stylus type surface roughness meter is generally used. It is. However, as can be seen from the scale of FIG. 3, it is considered that the surface roughness meter has irregularities at a level where accurate roughness measurement is impossible. Therefore, in the present invention, as a value corresponding to Rz (conventional Rmax) measured with a surface roughness meter, the maximum difference between the peak and valley in the field of view of the observation image is defined as “cross-sectional height”. It is. In FIG. 3, the portion indicated by “d” is the height of the cross section, and can be determined to be about 65 nm. Moreover, in FIG. 3, the browning surface 2 is formed along the shape of the copper foil surface with a very uniform thickness and maintains a state of being completely in close contact with the surface of the underlying copper foil. There are no trouble spots such as the floatation surface 2 being lifted up, and there are no places where powder fall is predicted.

  On the other hand, when the browning treatment surface of the copper foil provided with the conventional browning treatment surface is subjected to FIB analysis from the cross section in the same manner as described above, the result shown in FIG. 4 is obtained. That is, it can be seen that the shape constituting the browning surface has grown in a dendritic shape and is considerably protruded from the underlying copper foil. Therefore, when the cross-sectional height (d) at this time is measured, it is about 180 nm, and it can be understood that the surface is considerably rough. Moreover, it can be said that the browning surface having a dendritic shape is a surface where the dendritic portion is easily broken and easily damaged, and it is natural that if the broken pieces fall off, powdering will occur. This is considered to be a cause of color unevenness when viewed from the browned surface.

  It can be understood that the surface-treated copper foil according to the present invention described above has a very smooth surface even when viewed from the FIB cross-sectional observation image of FIG. However, although it is a glossy browning treatment, it does not have a gloss that diffusely reflects the light received by the browning treatment surface, and the glossy surface of the electrolytic copper foil and the surface of the rolled copper foil are subjected to a browning treatment. Even in this case, the a value in the Lab color system is 4.0 or less. Here, as described as 4.0 or less, it also includes a matte state showing a negative value as gloss. Such a matted browned surface is easily formed when the roughened surface of the electrolytic copper foil is subjected to a browning treatment.

  Whether the surface of the browning surface is matte or not is preferably expressed using glossiness rather than the Lab color system. However, the glossiness of the browning surface according to the present invention should be classified according to the type of the base on which the browning surface is formed. One is that when the browning surface is a glossy surface of copper foil and the browning surface is formed, the glossiness [Gs (60 °)] is preferably 30 or less. is there. When the glossiness is 30 or more, a so-called black shining state occurs and the metallic luster becomes conspicuous. The glossy surface of the copper foil is described as a concept including the glossy surface of the electrolytic copper foil and the surface of the rolled copper foil.

  And when the foundation | substrate with an unevenness | corrugation like the rough surface of an electrolytic copper foil is selected, it is desirable for the said browning process surface that glossiness [Gs (60 degrees)] is 10 or less. When the glossiness is 10 or more, there is a high possibility that the surface tends to fall off due to the discoloration plating constituting the browning surface.

  Furthermore, it is desirable that the browning surface is obtained by forming the browning surface on the roughened surface of the copper foil, and the glossiness [Gs (60 °)] is 5 or less. The roughened surface is a surface that is intentionally roughened by a technique such as applying fine copper grains to the surfaces of the electrolytic copper foil and the rolled copper foil, and is a matte surface from the beginning. At this time, if a surface treatment layer having a glossiness of 5 or more is formed, the surface tends to fall off due to the discoloration plating that constitutes the browning surface.

  It has also been found that whether or not the cobalt plating layer is easily dissolved in the copper etching solution is greatly influenced by the plating conditions when performing cobalt plating. That is, the cobalt plating film obtained when adopting the method for producing a surface-treated copper foil according to the present invention to be described later has the best etching characteristics.

Second surface-treated copper foil: This surface-treated copper foil is obtained by forming a rust-proofing layer for ensuring long-term storage on the surface of the first surface-treated copper foil. The cross-sectional layer structure of the surface-treated copper foil 1c provided with the antirust treatment layer 5 on both surfaces of FIG. FIG. 6 shows the surface-treated copper foil 1d when the roughening treatment is omitted. As long as the purpose is to prevent rust as copper foil only, organic rust prevention such as imidazole and benzotriazole, inorganic rust prevention using zinc alloy such as zinc or brass, etc. that are generally used can be widely used. It is. In addition, when the cobalt sulfate plating layer is formed on one side, the rust prevention treatment layer should be provided on at least the opposite surface of the surface-treated copper foil according to the present invention provided with the cobalt sulfate plating layer. There is no problem.

  However, when the antirust treatment layers 5 are provided on both sides, these antirust treatment layers serve as a protective layer for the cobalt sulfate layer 4 and for preventing the fine copper grains 3 from falling off the roughening treatment layer 2. It plays the role of maintaining the appearance of the surface-treated copper foil over a long period of time. It is particularly preferable to provide the rust prevention treatment layer 5 with a zinc-nickel alloy layer or a zinc-cobalt layer. These antirust treatment layers 5 are considered to function as a dissolution promoter when the cobalt sulfate plating layer 4 is dissolved by etching by using it in combination with the cobalt sulfate plating layer 4. That is, the dissolution of the cobalt sulfate plating layer 4 occurs more quickly when the zinc sulfate plating layer 4 is provided alone than when the zinc sulfate alloy layer or the zinc-cobalt layer is provided.

  Furthermore, the cross-sectional layer structure of the surface treatment copper foil 1c provided with the antirust treatment layer 5 and the chromate treatment layer 6 on both surfaces is schematically shown in FIGS. As can be seen from the comparison between FIGS. 5 and 7 and FIGS. 6 and 8, the difference from the surface-treated copper foil provided with the antirust treatment layer 5 is only that the chromate treatment layer 6 is provided. The configuration of is the same.

  The chromate treatment layer 6 is formed on one side or both sides after the rust prevention treatment layer 5 made of zinc-nickel alloy or zinc-cobalt alloy is formed. The presence of the chromate treatment layer 6 significantly improves the oxidation resistance of the surface-treated copper foil, and effectively prevents cosmetic corrosion such as oxidative discoloration.

  The surface-treated copper foil provided with the browning treatment surface described above has a very uniform surface, has a small variation in color within the same plane, and has a smooth brownish surface with gloss, resulting in rubbing. This makes it easy to handle due to excellent scratch resistance. FIG. 9 is a scanning electron microscope of the browned surface of the surface-treated copper foil according to the present invention. FIG. 9 is compared with FIGS. 10, 11, and 12 used in the above description. It becomes clear that fine metal particles adhere extremely uniformly.

<Method for producing a surface-treated copper foil having a browned surface>
(Manufacturing method of a 1st surface treatment copper foil) As for the manufacturing method of the 1st surface treatment copper foil mentioned above, it is desirable to employ | adopt the manufacturing method including the following processes. This production method can be further subdivided according to the presence or absence of roughening treatment, and is divided into “first surface-treated copper foil production method A” and “first surface-treated copper foil production method B”. I will explain.

Manufacturing method A of 1st surface treatment copper foil: Here, the manufacturing method which employ | adopted the browning treatment method applicable regardless of the presence or absence of the roughening process of copper foil surface is demonstrated.

It does not matter whether the copper foil used in the method for producing a surface-treated copper foil according to the present invention is subjected to a roughening treatment as described above. And, there is no particular limitation on the conditions for roughening the copper foil surface, but it is preferable that some dark brown treatment can be performed at this stage. It is preferable to employ a method that allows the visible copper oxide to be deposited. For example, a copper electrolyte containing arsenic can be generally used for forming the ultrafine copper particles. For example, a copper sulfate-based solution having a concentration of 10 g / l copper, 100 g / l sulfuric acid, 1.5 g / l arsenic, a liquid temperature of 38 ° C., and a current density of 10 A / dm ² is used.

However, with the recent rise in environmental problems, there has been an increase in efforts to eliminate harmful elements that are likely to affect the human body as much as possible. Therefore, regarding the formation of fine copper particles in the present invention, it is preferable to use a copper electrolyte solution added with 9-phenylacridine instead of arsenic. 9-Phenylacridine plays a role similar to the role played by arsenic in the field of copper electrolysis, and enables the sizing effect of precipitated fine copper grains and uniform electrodeposition. The copper electrolyte for forming ultrafine copper particles to which 9-phenylacridine is added includes a copper concentration of 5-10 g / l, a sulfuric acid concentration of 100-120 g / l, a chlorine concentration of 20-30 ppm, and a 9-phenylacridine of 50- 300 mg / l, liquid temperature of 30 to 40 ° C., and current density of 5 to 20 A / dm ² are within a range in which an extremely stable electrolytic operation can be performed.

In the step a), a cobalt sulfate plating layer is formed on one side of the copper foil described above. The cobalt sulfate plating layer includes 8 g / to 10 g / l cobalt sulfate (heptahydrate), with a cobalt sulfate plating solution to pH 4.0 or more ranges as without stirring bath, 2A / dm ² Electrolysis is performed at the above current density to form a brownish cobalt sulfate plating layer. That is, this is the cobalt sulfate plating condition when the solution is not stirred. Here, when the amount of cobalt sulfate (7 hydrate) in the cobalt sulfate plating solution is less than 8 g / l, the electrodeposition rate of the formed cobalt sulfate plating layer becomes slow, and the thickness of the cobalt sulfate plating layer is inadequate. The tendency to become uniform becomes stronger. On the other hand, when cobalt sulfate (7 hydrate) exceeds 10 g / l, the color tone of the formed cobalt sulfate plating layer is not in a browned state.

  Moreover, it is preferable to adjust the solution pH of the cobalt sulfate plating solution at this time to a range of 4.5 to 5.5. Within this range, it is possible to obtain a good brown-cobalt plating layer with a good yield. It is not preferable to add another electrolyte such as sodium hydroxide or potassium hydroxide in order to adjust the pH. The brown color of the cobalt plating layer is easily transformed into a metallic color.

  Therefore, the solution pH is stabilized in the range of 4.0 or more as a result by keeping the metal ion concentration in the solution constant. In order to stabilize the cobalt ion concentration in the solution in this way, the cobalt ion content electrodeposited by using a soluble cobalt electrode is dissolved or supplied, or the metal ion concentration is continuously monitored for cobalt hydroxide. It is desirable to adopt a technique for stabilizing the cobalt ion concentration by appropriately using and adding.

A current of 2 A / dm ² or more is used as the current density when electrolysis is performed. Even if the above-mentioned cobalt sulfate plating solution flows an excessive electrolysis current and forms a plating surface with fine unevenness to some extent, the powder falling phenomenon hardly occurs from there. Therefore, it is not necessary to set an upper limit of the current density in particular, and it may be arbitrarily determined in consideration of productivity in the process in view of technical common sense.

The electrolysis time is ² to 5 seconds when the current density is 2 A / dm ^2, and more than 5 seconds when the current density is less than 2 A / dm ² , and the weight thickness is 90 mg / m ^{2 to} 160 mg. / M ² of cobalt sulfate plating layer is obtained . The electrolysis time described here is determined based on the conditions such as the above cobalt plating solution and current density. If the electrolysis time is too short, the cobalt plating amount becomes less than 90 mg / m ² and the surface is brown. Rather, the color tone is close to black. And if electrolysis time becomes too long, the amount of cobalt plating will be less than 160 mg / m ^2, and it will not be a brownish surface, but will have a color tone in which black and reddish purple are mixed.

  In the step b), the copper foil subjected to the above steps is washed with water and dried to obtain a surface-treated copper foil having a cobalt sulfate plating layer as a browned surface. There is no particular limitation on the washing method and the drying method here, and it is possible to adopt a generally considered method.

Production method B of first surface-treated copper foil: Here, a production method employing a browning treatment method particularly suitable when there is no roughening treatment on the copper foil surface will be described.

  The copper foil used in the method for producing a surface-treated copper foil according to the present invention is not subjected to a roughening treatment, but the cobalt sulfate plating layer itself formed by the following cobalt sulfate plating is a dense roughened surface. Thus, the same effect as that obtained by roughening one surface of the copper foil in advance is exhibited.

In the step a) at this time, cobalt sulfate (7 hydrate) is contained at 10 g / l to 40 g / l on one side without the roughening treatment of the copper foil described above, the pH is 4.0 or more, and the liquid temperature is 30. A brown sulfate cobalt sulfate plating layer is formed by electrolysis at a current density of 4 A / dm ² or less using a cobalt sulfate plating solution at a temperature not higher than ° C. as a stirring bath. That is, it is more preferable to employ plating conditions based on a stirring bath for a copper foil without a roughening treatment. Therefore, the fundamental difference from the manufacturing method A of the first surface-treated copper foil is that the cobalt sulfate plating solution used for cobalt sulfate plating is electrolyzed while stirring. The cobalt sulfate concentration tends to create a better browned state as the cobalt sulfate concentration is lower. However, when the cobalt sulfate (7 hydrate) in the cobalt sulfate plating solution is less than 10 g / l, the electrodeposition rate of the cobalt sulfate plating layer formed by employing the stirring bath is slow, and the cobalt sulfate plating layer This tends to result in a lack of industrial productivity due to a strong tendency to have a non-uniform thickness. On the other hand, when cobalt sulfate (7 hydrate) exceeds 40 g / l, the formed cobalt sulfate plating layer is difficult to form dense irregularities, and as a result, it is not in a good browning state.

  In addition, the solution pH of the cobalt sulfate plating solution at this time is 4.0 or more, and it is particularly preferable to adjust the pH in the range of 4.5 to 5.5. In this range, it is possible to stably obtain a good brown-cobalt plating layer with good yield. For this pH adjustment, it is not preferable to add another electrolyte such as sodium hydroxide or potassium hydroxide. As described above, the brown color of the cobalt plating layer easily changes into a metallic color. The solution pH is also stabilized in the range of 4.0 or higher by maintaining the metal ion concentration in the solution constant, as described above.

  The cobalt sulfate plating solution at this time is preferably used at a liquid temperature of 30 ° C. or lower. At this time, the lower the liquid temperature, the better the browned surface. If the liquid temperature is set to 30 ° C. or less, the first surface-treated copper foil production method A can obtain a browned surface that is better than the browned surface of the copper foil surface without the roughening treatment. Is possible.

A current of 4 A / dm ² or less is used as the current density when electrolysis is performed. Within this range, it is possible to form a cobalt sulfate plating layer having good fine irregularities with excellent adhesion to an organic agent or the like without roughening the copper foil surface. Usually, in order to obtain an uneven brownish brown plating surface, a method of flowing an electrolytic current that enters an excessive burn plating area is employed. However, here, the smaller the current density used for electrolysis, the more stable browning tends to be possible. Therefore, a current density as small as possible should be adopted, but a current density of 0.5 A / dm ² can be determined as the lower limit value in consideration of industrial productivity. On the other hand, when the current density exceeds 4 A / dm ² , the browning treatment at the same level as the browning treatment is performed on the surface of the copper foil without the roughening treatment in the manufacturing method A of the first surface-treated copper foil. This means that the meaning of adopting the manufacturing method B will be lost. Moreover, the browning treatment surface formed in the above-described current density range does not cause the powder falling phenomenon.

The electrolysis time in the case of using the stirring bath, when the current density is 1A / dm ² 5 to 8 seconds, adopted more than 8 seconds when ² below current density 1A / dm, weight thickness 90 mg / m ^A cobalt sulfate plating layer of ^{2 to} 160 mg / m ² is obtained . The electrolysis time described here is determined based on the conditions such as the above cobalt plating solution and current density. If the electrolysis time is too short, the cobalt plating amount becomes less than 90 mg / m ² and the surface is brown. Rather, the color tone is close to black. And if electrolysis time becomes too long, the amount of cobalt plating will be less than 160 mg / m ^2, and it will not be a brownish brown surface but a black and reddish purple color.

  In the step b), the copper foil subjected to the above steps is washed with water and dried to obtain a surface-treated copper foil having a cobalt sulfate plating layer as a browned surface. There is no particular limitation on the washing method and the drying method here, and it is possible to adopt a generally considered method.

(Method for producing second surface-treated copper foil)
In the case of the second surface-treated copper foil, a surface-treated copper foil having a cobalt sulfate plating layer as a browned surface is produced in the same manner as in the method for producing the first surface-treated copper foil. Layer formation is performed. Therefore, the manufacturing flow is as follows: “a) A brown cobalt sulfate plating layer is formed on one side of the copper foil. B) A rust prevention layer is formed on both sides or one side of the copper foil having the brown cobalt sulfate plating layer formed on one side. C) Then, it is washed with water and dried. " In other words, the first surface-treated copper foil manufacturing method (manufacturing method A and manufacturing method B) is merely an increase in the number of steps for forming the antirust treatment layer.

  Therefore, only the formation process of the antirust treatment layer will be described here. A rust preventive layer is formed on both sides or one side of the copper foil on which the formation of the brown cobalt sulfate plating layer is completed on one side. In the case of using conventionally known organic rust preventives such as imidazole and benzotriazole, and inorganic rust preventives such as commonly used zinc alloys such as zinc or brass, no special explanation is required and conventional methods are followed. Detailed explanation here is omitted.

Hereinafter, the case where the antirust treatment layer is formed by plating using a zinc-nickel alloy plating solution or a zinc-cobalt alloy plating solution will be described. First, the zinc-nickel alloy plating will be described. The zinc-nickel alloy plating solution used here is not particularly limited. For example, nickel sulfate is used to have a nickel concentration of 1 to 2.5 g / l, and zinc pyrophosphate is used to have a zinc concentration of 0.1 to 1 g. / L, potassium pyrophosphate 50-500 g / l, liquid temperature 20-50 ° C., pH 8-11, current density 0.3-10 A / dm ² , etc. are adopted.

Next, zinc-cobalt alloy plating will be described. The zinc-cobalt alloy plating solution used here is not particularly limited. For example, cobalt sulfate is used to have a cobalt concentration of 1 to 2.5 g / l, and zinc pyrophosphate is used to have a zinc concentration of 0.1 to 1 g. / L, potassium pyrophosphate 50-500 g / l, liquid temperature 20-50 ° C., pH 8-11, current density 0.3-10 A / dm ² , etc. are adopted. The anticorrosion treatment layer combining this zinc-cobalt alloy plating and the chromate treatment described later exhibits particularly excellent corrosion resistance.

  In the case of the second surface-treated copper foil, if a chromate layer is formed after forming a zinc-nickel alloy layer or a zinc-cobalt alloy layer on the surface of the copper foil, it is possible to obtain better corrosion resistance. It becomes. That is, a chromate treatment process may be provided after the formation of the above-mentioned rust prevention treatment layer. In this chromate treatment step, either a substitution treatment in which the chromate solution is brought into contact with the copper foil surface or an electrolytic chromate treatment in which a chromate film is formed by electrolysis in the chromate solution may be employed. is there. Also, the chromate solution used here can be in the range used in the usual method. And after that, a surface-treated copper foil provided with a browning surface is obtained by washing with water and drying.

<Electromagnetic wave shielding conductive mesh> The surface-treated copper foil provided with the browned surface according to the present invention described above has no powder fall off from the browned surface, and is excellent in brown color with excellent scratch resistance. However, the browning layer can be removed by a normal copper etching process. Therefore, it can be easily processed into an arbitrary shape by using a process for manufacturing a printed wiring board. Considering these things, it can be said that the electromagnetic wave shielding conductive mesh incorporated in the front panel of the plasma display panel is most suitable for use.

  The surface-treated copper foil provided with the browned surface according to the present invention has a very uniform color tone on the browned surface, has a small variation in color tone, and becomes a smooth brownish surface with gloss, scratches due to rubbing, etc. This makes it easy to handle. Moreover, although the cobalt sulfate plating layer is very thin, it exhibits a good brown color enough to withstand the electromagnetic wave shielding conductive mesh application of the front panel of the plasma display panel. And since the cobalt content is low, the etching characteristics are good, and the life of the solution can be extended without lowering the titer of ordinary iron chloride and sulfuric acid-hydrogen peroxide copper etchants. It becomes.

  In addition, the method for producing the surface-treated copper foil according to the present invention is capable of producing the surface-treated copper foil according to the present invention with a high yield, and the cobalt sulfate plating layer formed by adopting the production conditions described above is the most. It dissolves efficiently in a copper etchant.

  Below, the surface-treated copper foil provided with the browning treatment surface which has been described above is produced, and the result of producing an electromagnetic wave shielding conductive mesh using a copper etching solution is shown.

  In this embodiment, the 1st surface treatment copper foil 1a shown in FIG. 1 was manufactured, the electromagnetic wave shielding electroconductive mesh shape was manufactured experimentally by the etching method, and the etching performance was confirmed.

  In this embodiment, a copper foil having a nominal thickness of 15 μm obtained by electrolyzing a copper sulfate solution was used. The copper foil was immersed in this solution for 30 seconds using a dilute sulfuric acid solution having a sulfuric acid concentration of 150 g / l and a liquid temperature of 30 ° C. to clean the surface.

And the roughening process was performed to the single side | surface of nominal thickness 15 micrometer copper foil. The roughening treatment at this time is to form the fine copper particles 3 on one side of the copper foil B, which is a copper sulfate-based solution having a concentration of 10 g / l copper, 100 g / l sulfuric acid, 25 ppm chlorine, An electrolysis condition of 9-phenylacridine 140 mg / l, a liquid temperature of 38 ° C., a current density of 15 A / dm ² , and an electrolysis time of 2 seconds was employed.

a) As a step, a cobalt sulfate plating layer 4 was formed on the roughened surface 2 of the copper foil. The cobalt sulfate plating layer 4 is formed by adjusting the cobalt sulfate (7 hydrate) to 10 g / l, adjusting the pH to 5.0 and using a cobalt sulfate plating solution with a solution temperature of 30 ° C. as a non-stirring bath. Electrolysis was performed at a current density of dm ² for 3 seconds to form a brown cobalt sulfate plating layer (converted thickness: 94 mg / m ² ). At this time, the adjustment of the cobalt ion concentration in the solution is not particularly performed. This is because it was considered that it was unnecessary to adjust the metal ion concentration because of the short-time electrolysis.

  As a process of b), it is washed by showering pure water sufficiently, and is kept in a drying furnace with an atmospheric temperature of 150 ° C. for 4 seconds from an electric heater, draining water, and browning treatment with a very good color tone A surface-treated copper foil 1a having a surface was obtained. In addition, in principle, a water washing step with pure water for 15 seconds is provided between the steps described above to prevent the solution from being brought into the pretreatment step.

<Physical properties of surface-treated copper foil>
As a result of observing the cross section of the surface-treated copper foil provided with the browning treatment surface obtained through the above steps with a FIB apparatus, the cross section shown in FIG. 1 is obtained, and the cross-sectional height (d ) Was 60 nm, the a value in the Lab color system of the browned surface was 3.5, and the glossiness [Gs (60 °)] was 2.8. Moreover, the powder fall in the tape test by sticking an adhesive tape on the browning surface and peeling it off was not confirmed.

<Manufacture of electromagnetic wave shielding conductive mesh>
A dry film serving as an etching resist was bonded to both surfaces of the surface-treated copper foil obtained as described above. Then, only the dry film on the browned surface side is overlaid with a test mask film for producing an electromagnetic shielding conductive mesh, and the mesh pitch is 200 μm, the mesh line width is 10 μm, and the mesh bias angle is 45 °. A conductive mesh pattern having a mesh electrode portion was exposed to ultraviolet rays. At this time, the entire surface of the etching resist layer on the opposite side was also exposed to ultraviolet rays so that it could not be removed by subsequent development. Then, it developed using the alkaline solution and formed the etching resist pattern.

  And using the iron chloride etching liquid which is a copper etching liquid, copper etching was carried out from the browning process surface side, and the electromagnetic wave shielding conductive mesh was manufactured by peeling an etching resist layer after that. As a result, there was no etching residue and very good etching was performed.

In this example, as shown in FIG. 5, a second surface-treated copper foil 1c having a zinc-nickel alloy layer as a rust-proofing layer is produced, and an electromagnetic shielding conductive mesh shape is produced experimentally by an etching method. The etching performance was confirmed. Therefore, since it is common with Example 1 until the browning process layer by a cobalt sulfate plating layer is formed, only rust prevention process conditions are demonstrated. The equivalent thickness of the brown-cobalt cobalt sulfate plating layer is 94 mg / m ² as in Example 1.

Here, since the plating treatment using the zinc-nickel alloy plating solution was performed on both surfaces of the copper foil on which the formation of the brown-cobalt cobalt sulfate plating layer was completed on one surface of Example 1, the zinc-nickel alloy layers were formed on both surfaces. is there. The zinc-nickel alloy layer uses nickel sulfate, nickel concentration is 2.0 g / l, zinc pyrophosphate is used, zinc concentration is 0.5 g / l, potassium pyrophosphate 250 g / l, liquid temperature 35 ° C., pH 10, current Electrolysis was performed for 5 seconds under conditions of a density of 5 A / dm ² , and electrodeposited uniformly and smoothly on both surfaces.

  Then, the pure water was sufficiently showered and washed in the same manner as in Example 1 and retained in a drying furnace with an atmospheric temperature of 150 ° C. from an electric heater for 4 seconds to remove moisture and brown in a very good color tone. The surface-treated copper foil 1c provided with the chemical treatment surface was obtained. In addition, in principle, a water washing step with pure water for 15 seconds is provided between the steps described above to prevent the solution from being brought into the pretreatment step.

<Physical properties of surface-treated copper foil>
As a result of observing the cross-section of the surface-treated copper foil provided with the browning surface obtained through the above steps with a FIB apparatus, the cross-sectional height (d) of the browning surface is 70 nm, and the browning surface In the Lab color system, the a value was 3.4 and the glossiness [Gs (60 °)] was 2.7. Moreover, the powder fall in the tape test by sticking an adhesive tape on the browning surface and peeling it off was not confirmed.

<Manufacture of electromagnetic wave shielding conductive mesh>
A dry film serving as an etching resist was bonded to both surfaces of the surface-treated copper foil obtained as described above, and a conductive mesh pattern was formed in the same manner as in Example 1. As a result, there was no etching residue and very good etching was performed.

In the present embodiment, as shown in FIG. 7, a second surface-treated copper foil 1e having a zinc-nickel alloy layer and a chromate treatment layer as a rust prevention treatment layer is produced, and the electromagnetic shielding conductive mesh shape is formed by an etching method. Manufactured experimentally to confirm the etching performance. Therefore, since it is common with Example 1 until the browning process layer by a cobalt sulfate plating layer is formed, only rust prevention process conditions are demonstrated. The equivalent thickness of the brown-cobalt cobalt sulfate plating layer is 94 mg / m ² as in Example 1.

In the same manner as in Example 2, the rust-proofing layer was formed by forming a zinc-nickel alloy layer on both surfaces using a zinc-nickel alloy plating solution and then performing chromate treatment on both surfaces. Here, electrolytic chromate treatment was adopted, and electrolysis conditions were chromic acid 5.0 g / l, pH 11.5, liquid temperature 35 ° C., current density 8 A / dm ² , and electrolysis time 5 seconds.

  Then, after the formation of the chromate layer is completed, the pure water is sufficiently showered and washed, and is kept in a drying furnace with an atmospheric temperature of 150 ° C. for 4 seconds from an electric heater, and moisture is removed. A surface-treated copper foil 1e having a browned surface was obtained. In addition, in principle, a water washing step with pure water for 15 seconds is provided between the steps described above to prevent the solution from being brought into the pretreatment step.

<Physical properties of surface-treated copper foil>
As a result of observing the cross-section of the surface-treated copper foil provided with the browning surface obtained through the above steps with a FIB apparatus, the cross-sectional height (d) of the browning surface is 65 nm, and the browning surface In the Lab color system, the a value was 3.4 and the glossiness [Gs (60 °)] was 2.8. Moreover, the powder fall in the tape test by sticking an adhesive tape on the browning surface and peeling it off was not confirmed.

<Manufacture of electromagnetic wave shielding conductive mesh>
A dry film serving as an etching resist was bonded to both surfaces of the surface-treated copper foil obtained as described above, and a conductive mesh pattern was formed by the same method as in the first embodiment. As a result, there was no etching residue and very good etching was performed.

In the present embodiment, as shown in FIG. 5, a second surface-treated copper foil 1c having a zinc-cobalt alloy layer as a rust-proofing layer is produced, and an electromagnetic shielding conductive mesh shape is produced on an experimental basis by an etching method. The etching performance was confirmed. Therefore, since it is common with Example 1 until the browning process layer by a cobalt sulfate plating layer is formed, only rust prevention process conditions are demonstrated. The equivalent thickness of the brown-cobalt cobalt sulfate plating layer is 94 mg / m ² as in Example 1.

Here, both sides of the copper foil in which the formation of the brown cobalt sulfate plating layer on one side of Example 1 was plated using a zinc-cobalt alloy plating solution, and the zinc-cobalt alloy layer was formed on both sides. is there. The zinc-cobalt alloy layer uses cobalt sulfate, the cobalt concentration is 2.0 g / l, zinc pyrophosphate is used, the zinc concentration is 0.5 g / l, potassium pyrophosphate 250 g / l, liquid temperature 35 ° C., pH 10, current Electrolysis was performed for 5 seconds under conditions of a density of 5 A / dm ² , and electrodeposited uniformly and smoothly on both surfaces.

  Then, the pure water was sufficiently showered and washed in the same manner as in Example 1 and retained in a drying furnace with an atmospheric temperature of 150 ° C. from an electric heater for 4 seconds to remove moisture and brown in a very good color tone. The surface-treated copper foil 1c provided with the chemical treatment surface was obtained. In addition, in principle, a water washing step with pure water for 15 seconds is provided between the steps described above to prevent the solution from being brought into the pretreatment step.

<Physical properties of surface-treated copper foil>
As a result of observing the cross-section of the surface-treated copper foil provided with the browning surface obtained through the above steps with a FIB apparatus, the cross-sectional height (d) of the browning surface is 60 nm, and the browning surface In the Lab color system, the a value was 3.5 and the glossiness [Gs (60 °)] was 2.8. Moreover, the powder fall in the tape test by sticking an adhesive tape on the browning surface and peeling it off was not confirmed.

<Manufacture of electromagnetic wave shielding conductive mesh>
A dry film serving as an etching resist was bonded to both surfaces of the surface-treated copper foil obtained as described above, and a conductive mesh pattern was formed in the same manner as in Example 1. As a result, there was no etching residue and very good etching was performed.

In this embodiment, as shown in FIG. 7, a second surface-treated copper foil 1e having a zinc-cobalt alloy layer and a chromate treatment layer as a rust prevention treatment layer is produced, and an electromagnetic wave shielding conductive mesh shape is formed by an etching method. Manufactured experimentally to confirm the etching performance. Therefore, since it is common with Example 1 until the browning process layer by a cobalt sulfate plating layer is formed, only rust prevention process conditions are demonstrated. The equivalent thickness of the brown-cobalt cobalt sulfate plating layer is 94 mg / m ² as in Example 1.

In the same manner as in Example 4, the rust-proofing layer was formed by forming a zinc-cobalt alloy layer on both surfaces using a zinc-cobalt alloy plating solution and then performing chromate treatment on both surfaces. Here, electrolytic chromate treatment was adopted, and electrolysis conditions were chromic acid 5.0 g / l, pH 11.5, liquid temperature 35 ° C., current density 8 A / dm ² , and electrolysis time 5 seconds.

  Then, after the formation of the chromate layer is completed, the pure water is sufficiently showered and washed, and is kept in a drying furnace with an atmospheric temperature of 150 ° C. for 4 seconds from an electric heater, and moisture is removed. A surface-treated copper foil 1e having a browned surface was obtained. In addition, in principle, a water washing step with pure water for 15 seconds is provided between the steps described above to prevent the solution from being brought into the pretreatment step.

<Physical properties of surface-treated copper foil>
As a result of observing the cross-section of the surface-treated copper foil provided with the browning surface obtained through the above steps with a FIB apparatus, the cross-sectional height (d) of the browning surface is 65 nm, and the browning surface In the Lab color system, the a value was 3.4 and the glossiness [Gs (60 °)] was 2.8. Moreover, the powder fall in the tape test by sticking an adhesive tape on the browning surface and peeling it off was not confirmed.

<Manufacture of electromagnetic wave shielding conductive mesh>
A dry film serving as an etching resist was bonded to both surfaces of the surface-treated copper foil obtained as described above, and a conductive mesh pattern was formed by the same method as in the first embodiment. As a result, there was no etching residue and very good etching was performed.

Unlike Example 1, this example does not perform the roughening treatment on the surface of the copper foil, and in the same manner as in Example 1 below, a cobalt sulfate plating layer is used on the glossy surface side of the electrolytic copper foil without the roughening treatment. A browning treatment layer was formed and evaluated in the same manner as in Example 1. Therefore, the description of the process is the same as that of the first embodiment, and a description thereof is omitted here. The brown-cobalt cobalt sulfate plating layer had a converted thickness of 108 mg / m ² .

<Physical properties of surface-treated copper foil>
As a result of observing the cross-section of the surface-treated copper foil provided with the browning surface obtained through the above steps with a FIB apparatus, the cross-sectional height (d) of the browning surface is 70 nm, and the browning surface In the Lab color system, the a value was 3.8 and the glossiness [Gs (60 °)] was 26. Moreover, the powder fall in the tape test by sticking an adhesive tape on the browning surface and peeling it off was not confirmed.

<Manufacture of electromagnetic wave shielding conductive mesh>
A dry film serving as an etching resist was bonded to both surfaces of the surface-treated copper foil obtained as described above, and a conductive mesh pattern was formed by the same method as in the first embodiment. As a result, there was no etching residue and very good etching was performed.

  In the present embodiment, as in Example 6, the surface of the copper foil is not subjected to the roughening treatment, and the browning treatment is performed using the copper foil not subjected to the above-described roughening treatment, and the first shown in FIG. The surface-treated copper foil 1b was manufactured, and an electromagnetic shielding conductive mesh shape was experimentally manufactured by an etching method to confirm the etching performance.

  In this embodiment, a copper foil having a nominal thickness of 15 μm obtained by electrolyzing a copper sulfate solution was used. The copper foil was immersed in this solution for 30 seconds using a dilute sulfuric acid solution having a sulfuric acid concentration of 150 g / l and a liquid temperature of 30 ° C. to clean the surface.

And the cobalt sulfate plating layer was formed on the rough surface of the said copper foil as a) process, without giving a roughening process to the single side | surface of the said copper foil. The cobalt sulfate plating layer is formed by using a cobalt sulfate plating solution adjusted to 20 g / l of cobalt sulfate (7 hydrate), pH of 5.5, and a liquid temperature of 27 ° C. as a stirring bath, 1 A / dm ² Was formed as a brown cobalt sulfate plating layer (converted thickness: 150 mg / m ² ) by electrolysis at a current density of 7 seconds. At this time, the adjustment of the cobalt ion concentration in the solution is not particularly performed. This is because it was considered that it was unnecessary to adjust the metal ion concentration because of the short-time electrolysis.

  As a process of b), it is washed by showering pure water sufficiently, and is kept in a drying furnace with an atmospheric temperature of 150 ° C. for 4 seconds from an electric heater, draining water, and browning treatment with a very good color tone A surface-treated copper foil 1 having a surface was obtained. In addition, in principle, a water washing step with pure water for 15 seconds is provided between the steps described above to prevent the solution from being brought into the pretreatment step.

<Physical properties of surface-treated copper foil>
As a result of observing the cross section of the surface-treated copper foil provided with the browning treatment surface obtained through the above steps with a FIB apparatus, the cross-sectional height (d) of the browning treatment surface is 80 nm, and the browning treatment surface In the Lab color system, the a value was 3.8 and the glossiness [Gs (60 °)] was 25. Moreover, the powder fall in the tape test by sticking an adhesive tape on the browning surface and peeling it off was not confirmed.

<Manufacture of electromagnetic wave shielding conductive mesh>
A dry film serving as an etching resist was bonded to both surfaces of the surface-treated copper foil obtained as described above, and a conductive mesh pattern was formed by the same method as in the first embodiment. As a result, there was no etching residue and very good etching was performed.

  In the present embodiment, as in Example 6, the surface of the copper foil is not subjected to the roughening treatment, and the browning treatment is performed using the copper foil not subjected to the above-described roughening treatment, and the first shown in FIG. The surface-treated copper foil 1b was manufactured, and an electromagnetic shielding conductive mesh shape was experimentally manufactured by an etching method to confirm the etching performance.

  In this embodiment, a copper foil having a nominal thickness of 15 μm obtained by electrolyzing a copper sulfate solution was used. The copper foil was immersed in this solution for 30 seconds using a dilute sulfuric acid solution having a sulfuric acid concentration of 150 g / l and a liquid temperature of 30 ° C. to clean the surface.

And the cobalt sulfate plating layer was formed on the rough surface of the said copper foil as a) process, without giving a roughening process to the single side | surface of the said copper foil. Formation of cobalt sulfate plating layer, using a cobalt sulfate (heptahydrate) 10 g / l, the pH was adjusted to 5.5, the cobalt sulfate plating solution was liquid temperature 27 ° C. as a stirring bath, 1A / dm ² Was formed as a brown cobalt sulfate plating layer (converted thickness: 120 mg / m ² ) by electrolysis at a current density of 6 seconds. At this time, the adjustment of the cobalt ion concentration in the solution is not particularly performed. This is because it was considered that it was unnecessary to adjust the metal ion concentration because of the short-time electrolysis. The form of the formed cobalt sulfate plating layer is observed as shown in FIG.

  As a process of b), it is washed by showering pure water sufficiently, and is kept in a drying furnace with an atmospheric temperature of 150 ° C. for 4 seconds from an electric heater, draining water, and browning treatment with a very good color tone A surface-treated copper foil 1b having a surface was obtained. In addition, in principle, a water washing step with pure water for 15 seconds is provided between the steps described above to prevent the solution from being brought into the pretreatment step.

<Physical properties of surface-treated copper foil>
As a result of observing the cross section of the surface-treated copper foil provided with the browning treatment surface obtained through the above steps with a FIB apparatus, the cross section shown in FIG. 1 is obtained, and the cross-sectional height (d ) Was 80 nm, the a value in the Lab color system of the browned surface was 3.8, and the glossiness [Gs (60 °)] was 28. Moreover, the powder fall in the tape test by sticking an adhesive tape on the browning surface and peeling it off was not confirmed.

<Manufacture of electromagnetic wave shielding conductive mesh>
A dry film serving as an etching resist was bonded to both surfaces of the surface-treated copper foil obtained as described above, and a conductive mesh pattern was formed by the same method as in the first embodiment. As a result, there was no etching residue and very good etching was performed.

  In the present embodiment, as in Example 6, the surface of the copper foil is not subjected to roughening treatment, but is subjected to browning treatment to produce the first surface-treated copper foil 1b shown in FIG. A mesh shape was experimentally manufactured by an etching method, and etching performance was confirmed.

  In this embodiment, a copper foil having a nominal thickness of 15 μm obtained by electrolyzing a copper sulfate solution was used. The copper foil was immersed in this solution for 30 seconds using a dilute sulfuric acid solution having a sulfuric acid concentration of 150 g / l and a liquid temperature of 30 ° C. to clean the surface.

And the cobalt sulfate plating layer was formed on the rough surface of the said copper foil as a) process, without giving a roughening process to the single side | surface of the said copper foil. The cobalt sulfate plating layer was formed by using a cobalt sulfate plating solution adjusted to 40 g / l cobalt sulfate (7 hydrate), pH 5.5, and a liquid temperature of 27 ° C. as a stirring bath, 1 A / dm ² Was formed as a brown cobalt sulfate plating layer (converted thickness: 112 mg / m ² ) by electrolysis at a current density of 5 seconds. At this time, the adjustment of the cobalt ion concentration in the solution is not particularly performed. This is because it was considered that it was unnecessary to adjust the metal ion concentration because of the short-time electrolysis. The form of the formed cobalt sulfate plating layer is observed as shown in FIG.

  As a process of b), it is washed by showering pure water sufficiently, and is kept in a drying furnace with an atmospheric temperature of 150 ° C. for 4 seconds from an electric heater, draining water, and browning treatment with a very good color tone A surface-treated copper foil 1b having a surface was obtained. In addition, in principle, a water washing step with pure water for 15 seconds is provided between the steps described above to prevent the solution from being brought into the pretreatment step.

<Physical properties of surface-treated copper foil>
As a result of observing the cross section of the surface-treated copper foil provided with the browning treatment surface obtained through the above steps with a FIB apparatus, the cross section shown in FIG. 1 is obtained, and the cross-sectional height (d ) Was 70 nm, the a value in the Lab color system of the browned surface was 3.8, and the glossiness [Gs (60 °)] was 28. Moreover, the powder fall in the tape test by sticking an adhesive tape on the browning surface and peeling it off was not confirmed.

<Manufacture of electromagnetic wave shielding conductive mesh>
A dry film serving as an etching resist was bonded to both surfaces of the surface-treated copper foil obtained as described above, and a conductive mesh pattern was formed by the same method as in the first embodiment. As a result, there was no etching residue and very good etching was performed.

In this example, a second surface-treated copper foil 1d having a zinc-cobalt alloy layer as a rust-proofing layer as shown in FIG. 6 was produced, and the electromagnetic shielding conductive mesh shape was experimentally tested by an etching method. Manufactured and checked for etching performance. Accordingly, until the browning treatment layer is formed by the cobalt sulfate plating layer, the process is the same as in Example 7, and only the rust prevention treatment conditions will be described. The equivalent thickness of the brown cobalt sulfate plating layer is 150 mg / m ² as in Example 7.

  Here, a zinc-cobalt alloy layer was formed on both surfaces of the copper foil on which the formation of the brown-cobalt cobalt sulfate plating layer on one surface of Example 7 was completed under the same conditions as in Example 4. Then, the pure water was sufficiently showered and washed in the same manner as in Example 1 and retained in a drying furnace with an atmospheric temperature of 150 ° C. from an electric heater for 4 seconds to remove moisture and brown in a very good color tone. The surface-treated copper foil 1d provided with the chemical treatment surface was obtained. In addition, in principle, a water washing step with pure water for 15 seconds is provided between the steps described above to prevent the solution from being brought into the pretreatment step.

<Physical properties of surface-treated copper foil>
As a result of observing the cross section of the surface-treated copper foil provided with the browning treatment surface obtained through the above steps with a FIB apparatus, the cross-sectional height (d) of the browning treatment surface is 80 nm, and the browning treatment surface In the Lab color system, the a value was 3.8 and the glossiness [Gs (60 °)] was 24. Moreover, the powder fall in the tape test by sticking an adhesive tape on the browning surface and peeling it off was not confirmed.

<Manufacture of electromagnetic wave shielding conductive mesh>
A dry film serving as an etching resist was bonded to both surfaces of the surface-treated copper foil obtained as described above, and a conductive mesh pattern was formed in the same manner as in Example 1. As a result, there was no etching residue and very good etching was performed.

In this embodiment, as shown in FIG. 8, a second surface-treated copper foil 1f having a zinc-cobalt alloy layer and a chromate treatment layer as a rust prevention treatment layer is produced, and the electromagnetic shielding conductive mesh shape is formed by an etching method. Manufactured experimentally to confirm the etching performance. Accordingly, until the browning treatment layer is formed by the cobalt sulfate plating layer, the process is the same as in Example 7, and only the rust prevention treatment conditions will be described. The equivalent thickness of the brown cobalt sulfate plating layer is 150 mg / m ² as in Example 7.

  In the same manner as in Example 4, the rust-proofing layer was formed by forming a zinc-cobalt alloy layer on both sides using a zinc-cobalt alloy plating solution and then performing the same chromate treatment on both sides as in Example 5. It was.

  Then, after the formation of the chromate layer is completed, the pure water is sufficiently showered and washed, and is kept in a drying furnace with an atmospheric temperature of 150 ° C. for 4 seconds from an electric heater, and moisture is removed. A surface-treated copper foil 1f having a browned surface was obtained. In addition, in principle, a water washing step with pure water for 15 seconds is provided between the steps described above to prevent the solution from being brought into the pretreatment step.

<Physical properties of surface-treated copper foil>
As a result of observing the cross section of the surface-treated copper foil provided with the browning treatment surface obtained through the above steps with a FIB apparatus, the cross-sectional height (d) of the browning treatment surface is 80 nm, and the browning treatment surface In the Lab color system, the a value was 3.8 and the glossiness [Gs (60 °)] was 24. Moreover, the powder fall in the tape test by sticking an adhesive tape on the browning surface and peeling it off was not confirmed.

<Manufacture of electromagnetic wave shielding conductive mesh>
A dry film serving as an etching resist was bonded to both surfaces of the surface-treated copper foil obtained as described above, and a conductive mesh pattern was formed by the same method as in the first embodiment. As a result, there was no etching residue and very good etching was performed.

  The surface-treated copper foil provided with the browned surface according to the present invention has no powder fall off from the browned surface, and can be etched using a normal copper etching solution. By using it as an electromagnetic shielding conductive mesh for the front panel, a high quality black mask can be formed. Moreover, if supply as a surface-treated copper foil provided with the browning process surface can be performed, the browning process process in the front panel manufacturing process can be omitted. Furthermore, the surface-treated copper foil provided with the browned surface can be applied to the surface treatment process of the conventional copper foil by adopting the above-described production method and does not require new production equipment. . Accordingly, a high-quality product can be manufactured with a high yield, so that the production cost can be reduced.

The figure which showed typically the cross-sectional layer structure of the surface treatment copper foil provided with the browning process surface. The figure which showed typically the cross-sectional layer structure of the surface treatment copper foil provided with the browning process surface. An observation image obtained by observing a cross section of the surface-treated copper foil using a focused ion beam processing observation apparatus. An observation image of a cross section of a surface treated copper foil (conventional product) observed using a focused ion beam processing observation apparatus. The figure which showed typically the cross-sectional layer structure of the surface treatment copper foil provided with the browning process surface. The figure which showed typically the cross-sectional layer structure of the surface treatment copper foil provided with the browning process surface. The figure which showed typically the cross-sectional layer structure of the surface treatment copper foil provided with the browning process surface. The figure which showed typically the cross-sectional layer structure of the surface treatment copper foil provided with the browning process surface. Scanning electron microscope image of the cobalt sulfate plating layer observed. The scanning electron microscope image of the conventional surface treatment copper foil provided with a blackening treatment surface. The scanning electron microscope image of the conventional surface treatment copper foil provided with a blackening treatment surface. A scanning electron microscope image of a conventional surface-treated copper foil having a browned surface.

Explanation of symbols

1a, 1b, 1c Surface-treated copper foil 1d, 1e, 1f
2 Roughening treatment layer 3 Fine copper particles 4 Cobalt sulfate plating layer 5 Rust prevention treatment layer (zinc-nickel alloy layer or zinc-cobalt alloy layer)
6 Chromate treatment layer 7 Copper foil layer

Claims (12)

A surface-treated copper foil having a browned surface,
The brown treatment surface is cobalt sulfate plating layer weight thickness ^{90mg / m 2 ~160mg / m 2} , is a value at the section height of the brown treatment surface 150nm or less, Lab color system 4. A surface-treated copper foil having a browned surface, which is 0 or less . The browning surface-treated copper foil according to claim 1, wherein the browning surface is provided with a rust-proofing layer. The surface-treated copper foil provided with the browning treatment surface according to claim 1 or 2, wherein the rust prevention treatment layer uses zinc or a zinc alloy. A surface-treated copper foil provided with the browning treatment surface of Claim 2 or Claim 3 which consists of a layer formed using zinc or a zinc alloy, and a chromate treatment layer. The browning treatment surface is obtained by forming the browning treatment surface shiny side of the copper foil, and any of claims 1 to 4 Gloss [Gs (60 °)] is 30 or less The browned surface-treated copper foil according to crab. The browning treatment surface is for the rough surface of electrolytic copper foil were formed the browning treatment surface, and gloss [Gs (60 °)] is of claims 1 to 5 is 10 or less The browning surface-treated copper foil in any one. The browning treatment surface is obtained by forming the browning process surface roughened surface of the copper foil, and gloss [Gs (60 °)] is of claims 1 to 6 is 5 or less The browning surface-treated copper foil in any one. A method for producing a surface-treated copper foil provided with a browned surface, which is a method for producing a surface-treated copper foil provided with a browned surface, comprising the following steps a) and b).
a) On the surface of the copper foil, an unstirred bath of cobalt sulfate plating solution containing 8 g / l to 10 g / l of cobalt sulfate (7 hydrate) and having a pH in the range of 4.0 or more was used. electrolytically in ^two or more current density, to form a cobalt sulfate plating layer of brown-based weight thickness ^{90mg / m 2 ~160mg / m 2} .
b) Thereafter, it is washed with water and dried. A method for producing a surface-treated copper foil comprising a browned surface, the method comprising producing a surface-treated copper foil comprising a browned surface, comprising the following steps a) to c):
a) On the surface of the copper foil, an unstirred bath of cobalt sulfate plating solution containing 8 g / l to 10 g / l of cobalt sulfate (7 hydrate) and having a pH in the range of 4.0 or more was used. electrolytically in ^two or more current density, to form a cobalt sulfate plating layer of brown-based weight thickness ^{90mg / m 2 ~160mg / m 2} .
b) A rust prevention layer is formed on both sides or one side of a copper foil having a brown cobalt sulfate plating layer formed on one side.
c) Thereafter, it is washed with water and dried. A method for producing a surface-treated copper foil provided with a browned surface, which is a method for producing a surface-treated copper foil provided with a browned surface, comprising the following steps a) and b).
a) Cobalt sulfate plating containing 10 g / l to 40 g / l of cobalt sulfate (7 hydrate) on the surface of copper foil not subjected to roughening treatment, pH of 4.0 or more and liquid temperature of 30 ° C. or less. using a stirring bath of liquid, 4A / dm ² and the electrolyte in the following current densities, to form a cobalt sulfate plating layer of brown-based weight thickness ^{90mg / m 2 ~160mg / m 2} .
b) Thereafter, it is washed with water and dried. A method for producing a surface-treated copper foil comprising a browned surface, the method comprising producing a surface-treated copper foil comprising a browned surface, comprising the following steps a) to c):
a) Cobalt sulfate plating containing 10 g / l to 40 g / l of cobalt sulfate (7 hydrate) on the surface of copper foil not subjected to roughening treatment, pH of 4.0 or more and liquid temperature of 30 ° C. or less. using a stirring bath of liquid, 4A / dm ² and the electrolyte in the following current densities, to form a cobalt sulfate plating layer of brown-based weight thickness ^{90mg / m 2 ~160mg / m 2} .
b) A rust prevention layer is formed on both sides or one side of a copper foil having a brown cobalt sulfate plating layer formed on one side.
c) Thereafter, it is washed with water and dried. The electromagnetic wave shielding electroconductive mesh for the front panel of the plasma display formed using the surface treatment copper foil provided with the browning process surface in any one of Claims 1-7.