JP4458521B2 - Surface-treated copper foil having a grayed 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 grayed surface and an electromagnetic wave shielding metal mesh for a front panel of a plasma display using the surface-treated copper foil. In particular, a surface-treated copper foil suitable for the production of an electromagnetic wave shielding conductive mesh for a front panel of a plasma display is provided.

  The conductive mesh for shielding the plasma display panel has been 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, due to the recent demand for power saving, development has been carried out with the target plasma generation signal voltage set to 200V to 50V level, and the circuit width of the conductive mesh has been made thinner to reduce the brightness associated with the voltage drop. Attempts have been made to reduce the coverage of the front glass panel with 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 incorporated into the front panel and is visible from the surface through the front glass, and is known to those skilled in the art to have a blackened surface or brownish color. Surface-treated copper foils having a modified surface have been used.

(Surface-treated copper foil with the current blackened surface)
One surface of the surface-treated copper foil processed into the conductive mesh is treated in black so as to enhance the brightness of transmitted light. Conventionally, a blackening treatment or the like for forming a copper oxide layer for improving the adhesion of the multilayer printed wiring board to the resin layer of the inner layer circuit has been diverted to this treatment.

  However, the blackening process described above 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 the blackened surface as the amount of adhesion increases, so-called powdering phenomenon occurs, the blackened surface is more likely to be damaged, and handling is easier. It becomes difficult. Also, the black color tone lacks stability.

  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, etc. have been studied as blackening treatments that can form a good blackened surface. There has been a problem that etching cannot be performed from the surface side. In particular, the surface-treated copper foil having a blackened surface on which cobalt or nickel is deposited in a rich manner cannot solve the problem of powder falling, and has been an expensive product because it uses a large amount of expensive nickel or the like.

(Surface-treated copper foil with the current browning surface)
On the other hand, the manufacturing technology of plasma display panels has matured, and conventionally, a surface-treated copper foil with a simply blackened surface has been required, but with the advancement of manufacturing technology and management, the black density of the electromagnetic shielding mesh is increased. However, an electromagnetic wave shielding mesh having a mesh pattern with a high aperture ratio, which is inexpensive, easy to etch, stable in light transmittance, and so on has been desired.

  Therefore, the 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, reducing the amount of dissimilar metals. I have tried to make it brownish brown.

  Certainly, considering that it meets the conditions of low price and is easy to etch, the surface of the surface-treated copper foil is in a brownish state before reaching blackening, reducing the amount of deposits of cobalt, etc. Supply has been considered.

  However, the disadvantage of the conventional 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 cannot be made uniform, which causes variations in the cross-sectional shape of the mesh obtained by etching. Moreover, the brown surface was easily damaged by merely rubbing the surface.

  Therefore, a surface-treated copper foil that has a browning treatment layer having a uniform brown color and that can be etched more easily has been desired in the market.

  And copper foil provided with the above-mentioned blackening processing surface and browning processing surface has a problem in stability of a color tone, and in order to make variation between lots small, it is necessary to perform manufacturing condition management strictly. Therefore, a large amount of process management labor and cost are required, and there is a certain limit in reducing the product price and supplying it to the market.

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 copper foil provided with the blackened surface and the browned surface described above is concerned with the color tone that can be confirmed in the state of the copper foil, and is processed into an electromagnetic wave shielding conductive mesh, and the front panel of the plasma display The color tone was not taken into account when it was incorporated into the.

  The most common front filter manufacturing method here will be outlined here. When manufacturing the conductive mesh 15 having a pitch of 200 μm and a line width of 20 μm or less, a PET film F is prepared as shown in FIG. The state shown in b) is assumed. Then, as shown in FIG. 14C, a metal seed layer S of 1 μm or less is formed on the adhesive layer 20 by using a sputtering method, an electroless plating method or the like, and thereafter, shown in FIG. 14D. Thus, a copper layer C having a level of 3 μm or less is formed by electrolytic copper plating.

  Then, an etching resist layer R is formed on the copper layer C as shown in FIG. 14 (e), and the conductive mesh pattern P is exposed on the etching resist layer R as shown in FIG. 15 (f). Then, development and etching are performed as shown in FIG. 15 (g), and the state shown in FIG. 15 (h) is obtained. When the etching resist layer R is peeled off, the state shown in FIG. 15 (i) is obtained.

  Subsequently, the surface of the conductive mesh 15 is blackened so that the blackened layer 17 is formed on the surface of the conductive mesh as shown in FIG. And when this blackening process is completed, as shown in FIG.16 (k), the first transparent substrate 19a constituting the front filter is brought into contact with the blackened conductive mesh 5 'and pressed, As shown in FIG. 16 (l), the blackened conductive mesh 15 ′ is pushed into the adhesive layer 20 to perform a transparent treatment. Then, as shown in FIG. 16 (m), the PET film is peeled off. Finally, as shown in FIG. 16 (n), the adhesive layer 20 and the second transparent substrate 19b are bonded together to complete the front filter 11.

  As can be seen from the above process, even if it is not visible due to blackening or browning before the clearing treatment, the conductive mesh surface becomes blackened and visible in the state of being adhered to the transparent resin or transparent substrate after the clearing treatment. Anything that can be done is considered good.

  In the future, digitalization of terrestrial waves is planned, and it is inevitable that the transmission speed of image signals will increase. Considering the effects on the human body and other electronic devices, etc. It is expected that laws and regulations on electromagnetic shields will be strengthened, and the demand for front filters that use conductive meshes and have excellent electromagnetic shielding properties is expected to increase further, and cheap and high-quality conductive meshes are desired. It is.

  Therefore, as a result of earnest research, the inventors of the present invention have come up with the idea of manufacturing a conductive mesh for shielding electromagnetic waves using a surface-treated copper foil having a grayed surface described below. By using the surface-treated copper foil having the graying surface, the color tone of the conductive mesh surface for shielding electromagnetic waves is gray before the transparentizing treatment in the manufacturing process of the front filter of the plasma display panel. Later, the surface of the conductive mesh for shielding electromagnetic waves becomes black and becomes visible.

<Surface treated copper foil with a grayed surface>
The surface-treated copper foil provided with the graying-treated surface according to the present invention includes a case where a rust prevention treatment layer is not provided and a case where a rust prevention treatment layer is provided. 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.

First surface-treated copper foil: The surface-treated copper foil according to the present invention is “a surface-treated copper foil having a grayed surface on a rough surface of an electrolytic copper foil, and the grayed surface is a copper foil layer. a cobalt sulfate plating layer weight thickness 200mg ^{/ m 2} ~350mg ^/ m 2 provided on one side of, and a surface-treated copper foil cross-section height of the graying treated surface and wherein the at 200nm or less (Hereinafter referred to as “first surface-treated copper foil”). Is. FIG. 1 schematically shows the cross-sectional layer structure of the surface-treated copper foil 1a.

  In FIG. 1, a cobalt sulfate plating layer 4 is formed on the rough surface of the electrolytic copper foil 7, and the opposite surface (corresponding to a glossy surface in the case of the electrolytic copper foil) is roughened with fine copper particles 3. The surface-treated copper foil 1a in the finished state is schematically described as an example. However, the opposite surface of the copper foil used at this time may be roughened or not roughened. FIG. 2 schematically shows the surface-treated copper foil 1b when the roughening treatment on the opposite surface is omitted. The roughening treatment layer 2 composed of the fine copper particles 3 is formed for the purpose of improving adhesiveness with a base material or the like, and may be provided as necessary. As the method for forming the roughened layer 2, it is possible to employ a method of adhering and forming fine copper grains as described above, a method of adhering fine copper oxide, and the like. There is no limitation on the method.

  Then, the cobalt sulfate plating layer 4 is provided on the roughened surface having certain irregularities of the copper foil layer 7. Here, the roughness corresponding to the rough surface of the electrolytic copper foil having a nominal thickness of 35 μm or less is most suitable as the roughness of the rough surface, and a stylus type roughness with a radius of curvature of 2 μm at the tip of the stylus. It is preferable that the average roughness (Ra) defined in JIS B 0601 when measured with a dynamometer is 1.0 μm or less and the 10-point average roughness (Rz) is in the range of 4.0 μm or less. If it is rougher than this roughness, the gray-colored surface-treated copper foil lacks color tone stability, the etching accuracy when etching into a mesh shape is deteriorated, and a high-quality conductive mesh for shielding electromagnetic waves is deteriorated. Manufacturing yield tends to be poor. More preferably, the average roughness (Ra) is 0.5 μm or less, and the 10-point average roughness (Rz) is 2.8 μm or less. The stability of the gray color tone of the surface-treated copper foil is remarkably improved, and the black color tone after the transparent treatment in the front panel manufacturing process of the plasma display panel is also less varied.

  The cobalt sulfate plating layer 4 here is used to mean a layer formed by a plating method using a cobalt sulfate solution. And this cobalt sulfate plating layer 4 can be visually recognized as gray in the state of surface-treated copper foil. However, after the transparent treatment is performed in the above-described front panel manufacturing process of the plasma display panel and the grayed surface is covered with a resin film or an adhesive resin, it can be visually recognized as black. It is. The color tone changes in this way because when dark clothes get wet with water, a water curtain is formed on the surface of the clothing that should have been rough, and a smooth surface is formed. The diffuse reflection is suppressed, and the same effect as that which can be visually recognized as a darker color tone can be obtained.

The cobalt sulfate plating layer 4 is, by those of adopting a manufacturing method to be described later weight thickness ^{200mg / m 2 ~350mg / m 2} , excellent in solubility in copper etching solution, and, graying surface It can be formed. A cobalt layer of a copper foil provided with a black plating film using a conventional cobalt layer has a weight thickness of about 1000 mg / m ² and is very thick, and the quality of the solubility of the plating layer is different. It was. 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 conversion weight in this invention is a value 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.

  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 the method for producing a surface-treated copper foil according to the present invention described later is employed has the best etching characteristics.

  The second feature of the surface-treated copper foil according to the present invention is that the surface shape of the grayed surface is not very rough, and the sectional height of the grayed surface is 200 nm or less. It is. That is, it can be said that it is an extremely smooth graying surface. 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 200 nm or less, Of course, there may be a cross-sectional height of more than 200 nm to reflect the variation in the manufacturing process. In order to measure the cross-sectional height of the cobalt sulfate plating layer 4 of the surface-treated copper foil 1 according to the present invention, a FIB observation image obtained by cross-sectional observation using a FIB analyzer is shown in FIG. FIG. 3 shows the electrolytic copper foil having a gray surface on the glossy surface. The FIB 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 graying 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 Rmax when measured with a surface roughness meter, the maximum difference between the peak portion and the valley portion in the field of view of the FIB observation image is set as the “section height”. The portion indicated by “d” in FIG. 3 is the cross-sectional height of FIG. 3 and can be determined to be about 80 nm. Moreover, in FIG. 3, the cobalt sulfate plating layer 4 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 underlying copper foil surface. There are no defects such as the cobalt plating layer 4 being lifted, and there are no spots that make powder fall off.

  On the other hand, when the blackened surface formed on the surface of the conventional copper foil is observed from the cross section in the same manner as described above, the results shown in FIGS. 4 and 5 are obtained. That is, it can be seen that the shape constituting the blackening treatment surface grows in a dendritic shape and is considerably protruded from the underlying copper foil. Accordingly, when the cross-sectional height (d) at this time is measured, it can be understood that the surface in FIG. 4 is about 480 nm and the case in FIG. 5 is about 270 nm, which is a considerably rough surface. In addition, such a blackened surface having a dendritic shape can be said to be a surface where the dendritic part is easily broken and easily damaged, and it is natural that powder breakage occurs if the broken piece falls off. This is considered to be a cause of color unevenness when visually observed from the blackened surface.

  It can be understood that the surface-treated copper foil according to the present invention described above has a very smooth surface from the FIB cross-sectional observation image of FIG. The L value in the Lab color system of this graying surface is 43 or less. Here, as described as 43 or less, the upper limit is not particularly limited, but empirically, about 38 seems to be the lower limit.

  In addition, the grayed surface of the surface-treated copper foil according to the present invention also has a certain gloss, and it is preferable to use the glossiness to express the degree of gloss. As for the glossiness of the graying surface according to the present invention, it is preferable that the glossiness [Gs (60 °)] is 10 or less as a result of forming the graying surface on the rough surface of the electrolytic copper foil. When the glossiness is 10 or more, so-called metallic luster becomes conspicuous. In this case as well, the lower limit of glossiness is not defined, but empirically about 0.5 seems to be the lower limit. More preferably, the glossiness is in the range of 0.5 to 3.0. When the glossiness is in this range, the gray color tone is most stable.

  The grayed surface of the surface-treated copper foil described above can be visually recognized as black when a transparent resin film is placed in close contact with the surface. The black density when directly observing the grayed surface at this time is 0.7 to 1.2 (measurement conditions: Status T, Sampling aperture 1.5 × 2 mm, no polarizing filter). When the transparent resin film is closely disposed, the black density is 1.4 or more (empirically, the upper limit is about 1.8). Conventionally, the black density of the blackened surface of the surface-treated copper foil used for the electromagnetic wave shielding mesh of the plasma display panel is about 1.0 or more when the blackened surface is directly observed (this invention) Measured by a product available on the market of the consumer, etc., 1.30 to 1.67), and when the transparent resin film is closely disposed on the surface of the blackened surface, the black density is 1.5 or more (this inventor) It is 1.40 to 1.87) when measured with a product available on the market. From this, considering that the black density is about 1.4 or more when the transparent resin film is closely disposed on the surface using the surface-treated copper foil having the grayed surface according to the present invention, sufficient blackness is obtained. It can be said that it becomes concentration. The black density in the present invention is measured based on JIS B 9620 and JIS B 9622, and the above-described measurement conditions are adopted.

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. 6 is schematically illustrated. FIG. 7 shows the surface-treated copper foil 1d when the roughening treatment is omitted on one side. 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.

  Further, FIG. 8 and FIG. 9 schematically show the cross-sectional layer structure of the surface-treated copper foil 1c provided with the antirust treatment layer 5 and the chromate treatment layer 6 on both sides. As can be seen from the comparison between FIG. 6 and FIG. 8, and FIG. 7 and FIG. 9, the difference from the surface-treated copper foil provided with the antirust treatment layer 5 is only the provision of the chromate treatment layer 6. 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.

<Manufacturing method of surface-treated copper foil provided with a grayed 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 manufacturing method is premised on employing a stirring bath.

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 on the opposite surface on which the cobalt sulfate plating layer is formed as described above. Here, as a precaution, there is no particular limitation on the conditions when the roughening treatment is performed. For example, in the case of forming the ultrafine copper grains, a copper electrolyte containing arsenic is generally used. It is possible to use. For example, a copper sulfate-based solution, copper concentration 5 to 10 g / l, sulfuric acid concentration 100 to 120 g / l, chlorine concentration 20 to 30 ppm, 9-phenylacridine 50 to 300 mg / l, liquid temperature 30 to 40 ° C., current For example, the density is 5 to 20 A / dm ² .

In the step a), cobalt sulfate plating including 10 g / l to 40 g / l of cobalt sulfate (7 hydrate) on the rough surface of the copper foil described above, having a pH of 4.0 or more and a liquid temperature of 30 ° C. or less. The solution is used as a stirring bath and electrolyzed at a current density of 4 A / dm ² or less to form a gray cobalt sulfate plating layer. That is, 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 grayed 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 using the stirring bath becomes slow, and the nickel sulfate layer This tends to make the thickness non-uniform, resulting in a lack of industrial productivity. 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 gray state.

  At this time, the solution pH of the cobalt sulfate plating solution is preferably adjusted to a range of 4.0 or more. And more preferably, it is the range of 4.5-5.5. Within this range, a good gray cobalt plating layer can be obtained with good yield. It is not preferable to add another electrolyte such as sodium hydroxide or potassium hydroxide in order to adjust the pH. It is easy to add a metallic color to the gray of the cobalt plating layer.

  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.

  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 grayed surface. If the liquid temperature is set to 30 ° C. or lower, in the first surface-treated copper foil production method A, a better grayed surface can be obtained than when the surface of the copper foil without the roughening treatment is blackened. Is possible.

  The stirring at this time is preferably such that the flow rate of the solution resulting from the stirring is in the range of 20 cm / s to 40 cm / s. When the flow rate of the solution is less than 20 cm / s, in the above solution composition, the ion supply to the deposition surface of cobalt to be electrodeposited becomes slow, the time required for electrodeposition becomes long, and the obtained graying Variations in the color of the treated surface are likely to occur. On the other hand, when the flow rate of the solution exceeds 40 cm / s, the ion supply rate by stirring becomes too high, the graying treatment surface becomes close to blackening, and the metallic luster becomes strong. It is no longer the graying surface where it is.

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 material or the like without roughening the copper foil surface. Usually, in order to obtain an uneven black plating surface, a method of flowing an electrolytic current that enters an excessive burn plating region is employed. However, here, the smaller the current density used for electrolysis, the more stable graying 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, if the current density exceeds 4 A / dm ² , a color tone close to blackening tends to be obtained, and the meaning of adopting this manufacturing method will be lost. Moreover, the graying-treated surface formed in the above-described current density range does not cause a powder falling phenomenon.

  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 grayed 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 grayed surface is produced in the same manner as the above-described method for producing the first surface-treated copper foil. Layer formation is performed. Therefore, the manufacturing flow is “a) forming a gray cobalt sulfate plating layer on the glossy surface of the copper foil. B) forming a rust prevention treatment layer on both sides or one side of the copper foil on which the gray cobalt sulfate plating layer is formed. c) Then, it is washed with water and dried. " That is, only the formation process of the antirust process layer increased in the manufacturing method of the 1st surface treatment copper foil.

  Therefore, only the formation process of the antirust treatment layer will be described here. The antirust treatment layer is formed on both sides or one side of the copper foil after the formation of the gray cobalt sulfate plating layer. 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 graying surface is obtained by washing with water and drying.

<Electromagnetic wave shielding conductive mesh> The surface-treated copper foil provided with the graying surface according to the present invention described above has no powder fall off from the graying surface, and has a good gray, The grayed layer can be etched away 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 having a grayed surface according to the present invention can only withstand electromagnetic wave shielding conductive mesh applications for the front panel of a plasma display panel, despite the fact that the cobalt sulfate plating layer is very thin. It has a good gray color. 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.

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

  Below, the surface-treated copper foil provided with the graying process surface mentioned above is manufactured, and suppose that the result of having manufactured the electromagnetic wave shielding electroconductive mesh using copper etching liquid 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 glossy surface of the nominal thickness 15 micrometer electrolytic copper foil. The roughening treatment at this time is to form the fine copper particles 3 on one side of the copper foil 7, and 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. FIG. 10 shows the surface of the roughened copper foil.

In step a), a cobalt sulfate plating layer was formed on the rough surface of the electrolytic copper foil as step a). 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 Thus, a gray cobalt sulfate plating layer (converted thickness: 270 mg / m ² ) was formed by electrolysis at a current density of 12 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. 11 and 12 show the cobalt sulfate plating layer formed. FIG. 11 is a scanning electron microscope image observed at a low magnification, and FIG. 12 is a scanning electron microscope image observed at a high magnification. As can be clearly seen from FIG. 12, the rough surface shape of the underlying electrolytic copper foil can be clearly understood, and it can be understood that the graying treatment layer itself is extremely thin.

  As the process of b), the pure water is sufficiently washed by showering, and is kept in a drying furnace with an atmospheric temperature of 150 ° C. for 4 seconds from an electric heater to remove moisture, and a graying 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 grayed surface obtained through the above steps with a FIB apparatus, the cross-section shown in FIG. 3 was obtained, and the cross-sectional height (d ) Was 80 nm, the L value in the Lab color system of the grayed surface was 41, and the glossiness [Gs (60 °)] was 2.5. Further, no color unevenness was observed on the grayed surface, and no powder fall off was confirmed in the tape test by sticking and peeling the adhesive tape on the surface.

  Furthermore, it was judged whether the grayed surface of the obtained surface-treated copper foil was processed into an electromagnetic wave shielding mesh for plasma display and turned black when subjected to a transparent treatment. The black density of the grayed surface before forming the transparent resin film is 0.9, and an epoxy resin is applied to the grayed surface as a transparent resin film, dried and cured, and the cured epoxy resin layer is formed. An alternative method of observing the changed color tone of the grayed surface through was adopted. As a result, the grayed surface was observed as black with a black density of 1.5.

<Manufacture of electromagnetic shielding mesh for plasma display>
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 a dry film on the grayed surface side is overlaid with a test mask film for producing an electromagnetic wave shielding conductive mesh, and has a mesh pitch of 200 μm, a mesh line width of 10 μm, and a mesh bias angle of 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 pattern.

  Then, using an iron chloride etchant that is a copper etchant, copper etching was performed from the grayed surface side, and then the etching resist layer was peeled off to produce an electromagnetic wave shielding conductive mesh. As a result, there was no etching residue and very good etching was performed. FIG. 13 shows an etching state of a test pattern (13 μm width circuit) for evaluating the etching property. As can be seen from FIG. 13, there is no etching residue and a beautiful circuit having an extremely excellent etching factor is obtained.

In this example, as shown in FIG. 6, 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 on an experimental basis by an etching method. The etching performance was confirmed. Therefore, since it is common with Example 1 until the graying process layer by a cobalt sulfate plating layer is formed, only rust prevention process conditions are demonstrated. The equivalent thickness of the gray cobalt sulfate plating layer is 270 mg / m ² as in Example 1.

Here, since the plating treatment using the zinc-nickel alloy plating solution was performed on both sides of the copper foil on which the formation of the gray cobalt sulfate plating layer was finished on one side of Example 1, the zinc-nickel alloy layer was formed on both sides. 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 is sufficiently showered and washed in the same manner as in Example 1, and is kept in a drying furnace with an atmospheric temperature of 150 ° C. for 4 seconds from an electric heater to remove moisture, and a gray having 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 graying surface obtained through the above steps with a FIB apparatus, the same cross-section as shown in FIG. 3 was obtained, and the cross-sectional height of the graying surface was The L value in the Lab color system of the grayed surface was 39, and the glossiness [Gs (60 °)] was 2.5. Further, no color unevenness was observed on the grayed surface, and no powder fall off was confirmed in the tape test by sticking and peeling the adhesive tape on the surface.

  Furthermore, it was judged whether the grayed surface of the obtained surface-treated copper foil was processed into an electromagnetic wave shielding mesh for plasma display and turned black when subjected to a transparent treatment. The black density of the grayed surface before forming the transparent resin film was 0.9, and as a result of evaluation by the same alternative method as in Example 1, the grayed surface was observed as black with a black density of 1.6. did it.

<Manufacture of electromagnetic shielding mesh for plasma display>
In the same manner as in Example 1, an electromagnetic wave shielding conductive mesh was prototyped using the obtained surface-treated copper foil. As a result, even if a rust preventive layer was present, the etching operation was not hindered and 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 1e having a zinc-nickel 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 graying process layer by a cobalt sulfate plating layer is formed, only rust prevention process conditions are demonstrated. The equivalent thickness of the gray cobalt sulfate plating layer is 270 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 graying 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 graying surface obtained through the above steps with a FIB apparatus, the same cross-section as shown in FIG. 3 was obtained, and the cross-sectional height of the graying surface was The L value in the Lab color system of the grayed surface was 40, and the glossiness [Gs (60 °)] was 2.3. Further, no color unevenness was observed on the grayed surface, and no powder fall off was confirmed in the tape test by sticking and peeling the adhesive tape on the surface.

  Furthermore, it was judged whether the grayed surface of the obtained surface-treated copper foil was processed into an electromagnetic wave shielding mesh for plasma display and turned black when subjected to a transparent treatment. The black density of the grayed surface before forming the transparent resin film was 0.9, and as a result of evaluation by the same alternative method as in Example 1, the grayed surface was observed as black with a black density of 1.5. did it.

<Manufacture of electromagnetic shielding mesh for plasma display>
In the same manner as in Example 1, an electromagnetic wave shielding conductive mesh was prototyped using the obtained surface-treated copper foil. As a result, even if a rust preventive layer was present, the etching operation was not hindered and there was no etching residue, and very good etching was performed.

In this embodiment, as shown in FIG. 6, 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 graying process layer by a cobalt sulfate plating layer is formed, only rust prevention process conditions are demonstrated. The equivalent thickness of the gray cobalt sulfate plating layer is 270 mg / m ² as in Example 1.

Here, plating was performed using a zinc-cobalt alloy plating solution on both sides of the copper foil on which the formation of the gray cobalt sulfate plating layer was completed on the glossy surface of Example 1, and a zinc-cobalt alloy layer was formed on both sides. It is. 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 is sufficiently showered and washed in the same manner as in Example 1, and is kept in a drying furnace with an atmospheric temperature of 150 ° C. for 4 seconds from an electric heater to remove moisture, and a gray having 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 graying surface obtained through the above steps with a FIB apparatus, the same cross-section as shown in FIG. 3 was obtained, and the cross-sectional height of the graying surface was The L value in the Lab color system of the grayed surface was 40, and the glossiness [Gs (60 °)] was 2.5. Further, no color unevenness was observed on the grayed surface, and no powder fall off was confirmed in the tape test by sticking and peeling the adhesive tape on the surface.

  Furthermore, it was judged whether the grayed surface of the obtained surface-treated copper foil was processed into an electromagnetic wave shielding mesh for plasma display and turned black when subjected to a transparent treatment. The black density of the grayed surface before forming the transparent resin coating was 0.93, and as a result of evaluation by the same alternative method as in Example 1, the grayed surface was observed as black with a black density of 1.6. did it.

<Manufacture of electromagnetic shielding mesh for plasma display>
In the same manner as in Example 1, an electromagnetic wave shielding conductive mesh was prototyped using the obtained surface-treated copper foil. As a result, even if a rust preventive layer was present, the etching operation was not hindered and there was no etching residue, and very good etching was performed.

In this example, as shown in FIG. 8, a second surface-treated copper foil 1e having a zinc-cobalt alloy layer and a chromate-treated layer as a rust-proof treated layer is produced, and an 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 graying process layer by a cobalt sulfate plating layer is formed, only rust prevention process conditions are demonstrated. The equivalent thickness of the gray cobalt sulfate plating layer is 270 mg / m ² as in Example 1.

In the same manner as in Example 4, the antirust treatment layer was formed by forming a zinc-cobalt alloy layer on both sides using a zinc-cobalt alloy plating solution, and then performing chromate treatment on both sides. 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 graying 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 graying surface obtained through the above steps with a FIB apparatus, the same cross-section as shown in FIG. 3 was obtained, and the cross-sectional height of the graying surface was The L value in the Lab color system of the grayed surface was 41, and the glossiness [Gs (60 °)] was 2.4. Further, no color unevenness was observed on the grayed surface, and no powder fall off was confirmed in the tape test by sticking and peeling the adhesive tape on the surface.

  Furthermore, it was judged whether the grayed surface of the obtained surface-treated copper foil was processed into an electromagnetic wave shielding mesh for plasma display and turned black when subjected to a transparent treatment. The black density of the grayed surface before forming the transparent resin film was 0.9, and as a result of evaluation by the same alternative method as in Example 1, the grayed surface was observed as black with a black density of 1.6. did it.

<Manufacture of electromagnetic shielding mesh for plasma display>
In the same manner as in Example 1, an electromagnetic wave shielding conductive mesh was prototyped using the obtained surface-treated copper foil. As a result, even if a rust preventive layer was present, the etching operation was not hindered and there was no etching residue, and very good etching was performed.

Unlike Example 1, this example does not subject the rough surface of the electrolytic copper foil to a roughening treatment, and in the same manner as in Example 1 below, the gray surface treatment by the cobalt sulfate plating layer on the rough surface side of the electrolytic copper foil. The layer was formed, the 2nd surface treatment copper foil 1b shown in FIG. 2 was manufactured, and the same evaluation as Example 1 was performed. Therefore, the description of the process is the same as that of the first embodiment, and a description thereof is omitted here. The gray cobalt sulfate plating layer had a converted thickness of 268 mg / m ² . The form of the formed cobalt sulfate plating layer is observed as shown in FIGS.

<Physical properties of surface-treated copper foil>
As a result of observing the cross-section of the surface-treated copper foil provided with the graying surface obtained through the above steps with a FIB apparatus, the same cross-section as shown in FIG. 3 was obtained, and the cross-sectional height of the graying surface was The L value in the Lab color system of the grayed surface was 42, and the glossiness [Gs (60 °)] was 2.5. Further, no color unevenness was observed on the grayed surface, and no powder fall off was confirmed in the tape test by sticking and peeling the adhesive tape on the surface.

  Furthermore, it was judged whether the grayed surface of the obtained surface-treated copper foil was processed into an electromagnetic wave shielding mesh for plasma display and turned black when subjected to a transparent treatment. The black density of the grayed surface before forming the transparent resin film was 0.9, and as a result of evaluation by the same alternative method as in Example 1, the grayed surface was observed as black with a black density of 1.6. did it.

<Manufacture of electromagnetic shielding mesh for plasma display>
In the same manner as in Example 1, an electromagnetic wave shielding conductive mesh was prototyped using the obtained surface-treated copper foil. As a result, the etching operation was not hindered and there was no etching residue, and very good etching was performed.

  In this embodiment, as in Example 6, the first surface-treated copper foil 1b shown in FIG. 2 is manufactured by subjecting the roughened surface to a graying treatment without applying a roughening treatment to the shiny surface of the electrolytic copper foil. Then, an electromagnetic shielding conductive 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 in the rough surface of the said copper foil as a process. The cobalt sulfate plating layer was 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, 2 A / dm ^2. Was formed as a gray cobalt sulfate plating layer (converted thickness: 275 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 FIGS.

  As the process of b), the pure water is sufficiently washed by showering, and is kept in a drying furnace with an atmospheric temperature of 150 ° C. for 4 seconds from an electric heater to remove moisture, and a graying 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 graying surface obtained through the above steps with a FIB apparatus, the same cross-section as shown in FIG. 3 was obtained, and the cross-sectional height of the graying surface was The L value in the Lab color system of the grayed surface was 39, and the glossiness [Gs (60 °)] was 2.2. Further, no color unevenness was observed on the grayed surface, and no powder fall off was confirmed in the tape test by sticking and peeling the adhesive tape on the surface.

  Furthermore, it was judged whether the grayed surface of the obtained surface-treated copper foil was processed into an electromagnetic wave shielding mesh for plasma display and turned black when subjected to a transparent treatment. The black density of the grayed surface before forming the transparent resin film was 0.9, and as a result of evaluation by the same alternative method as in Example 1, the grayed surface was observed as black with a black density of 1.6. did it.

<Manufacture of electromagnetic shielding mesh for plasma display>
In the same manner as in Example 1, an electromagnetic wave shielding conductive mesh was prototyped using the obtained surface-treated copper foil. As a result, the etching operation was not hindered and there was no etching residue, and very good etching was performed.

  In this embodiment, as in Example 6, the first surface-treated copper foil 1b shown in FIG. 2 is manufactured by subjecting the roughened surface to a graying treatment without applying a roughening treatment to the shiny surface of the electrolytic copper foil. Then, an electromagnetic shielding conductive 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 in the rough surface of the said copper foil as a process. 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 Thus, a gray cobalt sulfate plating layer (converted thickness: 268 mg / m ² ) was formed by electrolysis at a current density of 12 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 FIGS.

  As the process of b), the pure water is sufficiently washed by showering, and is kept in a drying furnace with an atmospheric temperature of 150 ° C. for 4 seconds from an electric heater to remove moisture, and a graying 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 graying surface obtained through the above steps with a FIB apparatus, the same cross-section as shown in FIG. 3 was obtained, and the cross-sectional height of the graying surface was The L value in the Lab color system of the grayed surface was 40, and the glossiness [Gs (60 °)] was 2.6. Further, no color unevenness was observed on the grayed surface, and no powder fall off was confirmed in the tape test by sticking and peeling the adhesive tape on the surface.

  Furthermore, it was judged whether the grayed surface of the obtained surface-treated copper foil was processed into an electromagnetic wave shielding mesh for plasma display and turned black when subjected to a transparent treatment. The black density of the grayed surface before forming the transparent resin film was 0.9, and as a result of evaluation by the same alternative method as in Example 1, the grayed surface was observed as black with a black density of 1.5. did it.

<Manufacture of electromagnetic shielding mesh for plasma display>
In the same manner as in Example 1, an electromagnetic wave shielding conductive mesh was prototyped using the obtained surface-treated copper foil. As a result, the etching operation was not hindered and 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. 7 was manufactured, and the electromagnetic shielding conductive mesh shape was experimentally tested by an etching method. Manufactured and checked for etching performance. Therefore, until the graying treatment layer by the cobalt sulfate plating layer is formed, since it is common with Example 7, only the rust prevention treatment conditions will be described. The equivalent thickness of the gray cobalt sulfate plating layer is 268 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 gray cobalt sulfate plating layer was completed on one surface under the same conditions as in Example 4. Then, the pure water is sufficiently showered and washed in the same manner as in Example 1, and is kept in a drying furnace with an atmospheric temperature of 150 ° C. for 4 seconds from an electric heater to remove moisture, and a gray having 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 graying surface obtained through the above steps with a FIB apparatus, the same cross-section as shown in FIG. 3 was obtained, and the cross-sectional height of the graying surface was The L value in the Lab color system of the grayed surface was 41, and the glossiness [Gs (60 °)] was 2.4. Further, no color unevenness was observed on the grayed surface, and no powder fall off was confirmed in the tape test by sticking and peeling the adhesive tape on the surface.

  Furthermore, it was judged whether the grayed surface of the obtained surface-treated copper foil was processed into an electromagnetic wave shielding mesh for plasma display and turned black when subjected to a transparent treatment. The black density of the grayed surface before forming the transparent resin film was 0.9, and as a result of evaluation by the same alternative method as in Example 1, the grayed surface was observed as black with a black density of 1.5. did it.

<Manufacture of electromagnetic shielding mesh for plasma display>
In the same manner as in Example 1, an electromagnetic wave shielding conductive mesh was prototyped using the obtained surface-treated copper foil. As a result, the etching operation was not hindered and there was no etching residue, and very good etching was performed.

In this example, as shown in FIG. 9, a second surface-treated copper foil 1f having a zinc-cobalt alloy layer and a chromate-treated layer as a rust-proof treated layer is produced, and an electromagnetic shielding conductive mesh shape is formed by an etching method. Manufactured experimentally to confirm the etching performance. Therefore, until the graying treatment layer by the cobalt sulfate plating layer is formed, since it is common with Example 7, only the rust prevention treatment conditions will be described. The equivalent thickness of the gray cobalt sulfate plating layer is 270 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. The surface-treated copper foil 1f provided with the graying surface of this 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 graying surface obtained through the above steps with a FIB apparatus, the same cross-section as shown in FIG. 3 was obtained, and the cross-sectional height of the graying surface was The L value in the Lab color system of the grayed surface was 40, and the glossiness [Gs (60 °)] was 2.4. Further, no color unevenness was observed on the grayed surface, and no powder fall off was confirmed in the tape test by sticking and peeling the adhesive tape on the surface.

  Furthermore, it was judged whether the grayed surface of the obtained surface-treated copper foil was processed into an electromagnetic wave shielding mesh for plasma display and turned black when subjected to a transparent treatment. The black density of the grayed surface before forming the transparent resin film was 0.9, and as a result of evaluation by the same alternative method as in Example 1, the grayed surface was observed as black with a black density of 1.6. did it.

<Manufacture of electromagnetic shielding mesh for plasma display>
In the same manner as in Example 1, an electromagnetic wave shielding conductive mesh was prototyped using the obtained surface-treated copper foil. As a result, even if a rust preventive layer was present, the etching operation was not hindered and there was no etching residue, and very good etching was performed.

  The surface-treated copper foil provided with the graying surface according to the present invention has no color unevenness on the graying surface, no powder fall off from the surface, and etching using a normal copper etching solution It is possible to form a high-quality black mask without color unevenness by using it for the electromagnetic wave shielding conductive mesh of the front panel of the plasma display panel. Moreover, if supply as a surface-treated copper foil provided with the graying process surface can be performed, the blackening process process in the front panel manufacturing process can be omitted. Furthermore, the surface-treated copper foil provided with the grayed 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 with no color unevenness can be manufactured with a high yield, and the production cost can be reduced.

The figure which showed typically the cross-sectional layer structure of the surface treatment copper foil provided with a graying process surface. The figure which showed typically the cross-sectional layer structure of the surface treatment copper foil provided with a graying process surface. The FIB observation image of the cross-sectional layer structure of the surface treatment copper foil provided with a graying process surface. The FIB observation image of the cross-sectional layer structure of the surface treatment copper foil provided with a graying process surface. The FIB observation image of the cross-sectional layer structure of the surface treatment copper foil provided with a graying process surface. The figure which showed typically the cross-sectional layer structure of the surface treatment copper foil provided with a graying process surface. The figure which showed typically the cross-sectional layer structure of the surface treatment copper foil provided with a graying process surface. The figure which showed typically the cross-sectional layer structure of the surface treatment copper foil provided with a graying process surface. The figure which showed typically the cross-sectional layer structure of the surface treatment copper foil provided with a graying process surface. Scanning electron microscope image of the roughened copper foil surface. Scanning electron microscope image of a gray cobalt sulfate plating layer observed at a low magnification. Scanning electron microscope image of a gray cobalt sulfate plating layer observed at high magnification. Scanning electron microscope image of the etching test pattern. The schematic diagram showing the manufacture flow of the front panel of the conventional plasma display panel. The schematic diagram showing the manufacture flow of the front panel of the conventional plasma display panel. The schematic diagram showing the manufacture flow of the front panel of the conventional plasma display panel.

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 grayed surface on the rough surface of the electrolytic copper foil,
The graying process surface is cobalt sulfate plating layer weight thickness 200mg ^{/ m 2} ~350mg ^/ m 2 provided on one surface of a copper foil layer, and a cross-sectional height of the graying treated surface 200nm or less A surface-treated copper foil characterized by being. The surface-treated copper foil according to claim 1, wherein a rust-proofing layer is provided on the graying-treated surface. The surface-treated copper foil according to claim 1 or 2, wherein the antirust treatment layer is made of zinc or a zinc alloy. The surface-treated copper foil provided with the graying-treated surface according to claim 2 or 3, wherein the rust-proofing layer comprises a layer formed using zinc or a zinc alloy and a chromate-treated layer. The surface-treated copper foil according to any one of claims 1 to 4, wherein the graying surface has an L value in a Lab color system of 43 or less. The said graying process surface forms the said graying process surface in the rough surface of an electrolytic copper foil, and glossiness [Gs (60 degrees)] is 10 or less. The surface-treated copper foil in any one. The surface-treated copper foil according to any one of claims 1 to 6, wherein the graying surface has a black density of 0.7 to 1.2. The surface-treated copper foil according to any one of claims 1 to 7, wherein the graying-treated surface is visible as black when a transparent resin film is closely disposed on the surface. The surface-treated copper foil according to any one of claims 1 to 8, wherein a black density when a transparent resin coating is provided on the graying-treated surface is 1.2 or more. A method for producing a surface-treated copper foil comprising a grayed surface, the method comprising the following steps a) and b).
a) On the rough surface of the copper foil, a cobalt sulfate plating bath containing 10 g / l to 40 g / l of cobalt sulfate (7 hydrate), having a pH of 4.0 or higher and a liquid temperature of 30 ° C. or lower was used. Electrolysis is performed at a current density of 4 A / dm ² or less to form a gray cobalt sulfate plating layer.
b) Thereafter, it is washed with water and dried. A method for producing a surface-treated copper foil comprising a graying-treated surface provided with a rust-proofing layer, comprising the following steps a) to c).
a) A cobalt sulfate plating solution containing 10 g / l to 40 g / l of cobalt sulfate (7 hydrate) on the rough surface of the copper foil, having a pH of 4.0 or more and a solution temperature of 30 ° C. or less is used as a stirring bath. Electrolysis is performed at a current density of 4 A / dm ² or less to form a gray cobalt sulfate plating layer.
b) A rust preventive layer is formed on both sides or one side of the copper foil on which the gray cobalt sulfate plating layer is formed.
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 graying process surface in any one of Claims 1-9.