A method for reverse electrolytic copper foil electroplating blackening

Abstract

The present invention belongs to the field of copper foil electroplating, and specifically relates to a reverse electrolytic copper foil electroplating blackening method. The present invention selects ultra-low profile copper foil, pickles the surface of the copper foil to remove the surface oxide of the copper foil raw foil, reverses the smooth surface and the rough surface of the ultra-low profile copper foil, converts the rough surface of the traditional electrolytic copper foil to roughen and solidify the smooth surface, and after three roughening and three solidification, the smooth surface of the copper foil is electroplated again on the basis of the original bottom profile copper foil, so that new copper buds grow on the basis of the original copper grains, so that the smooth surface is roughened to different degrees, and then the treated surface is blackened electroplated, wherein the electroplating blackening liquid mainly plays a role in nickel-cobalt-copper, the pH value is controlled between 9-10, and the flow rate of the electroplating liquid is controlled at 5-8m 3 / h, current density 100-500A / m 2 , the temperature is 25-30℃, and the blackening electroplating is completed. The flow rate and current density can be finely adjusted according to the target color.

Description

Technical Field

[0001] The invention belongs to the field of copper foil electroplating, and in particular relates to a reverse electrolytic copper foil blackening method. Background Art

[0002] Reverse electrolytic copper foil (RTF) is based on traditional electrolytic copper foil, with both sides of the copper foil roughened to varying degrees. At the same time, the peeling strength of both sides of the copper foil is enhanced, so that when it is used as an intermediate material of the substrate, it strengthens the bonding strength with other materials. Compared with standard electrolytic copper foil, the matte surface of reverse copper foil is rougher and adheres well to lamination resists.

[0003] The application field of blackened copper foil is mainly in touch panel sensors. It is attached to the surface of the touch panel. Due to the metallic properties of copper itself, it will produce mirror reflection. In order to reduce the impact of this aspect and improve the user experience, the blackened copper foil will be blackened and electroplated on the processed surface of the standard electrolytic copper foil to suppress the reflection from the copper wiring, thereby reducing the contrast when it is mounted on the display as a touch panel sensor.

[0004] Blackening the reverse copper foil reduces the surface roughness of the traditional copper foil, reduces electrical loss, and strengthens the bonding with other materials. At the same time, blackening is performed and used on touch surface sensors, combining the advantages of reverse copper foil and blackened copper foil, gradually replacing the traditional blackened copper foil. Summary of the invention

[0005] In order to solve the above-mentioned technical problems, this application provides the following technical solutions:

[0006] This process combines the reverse copper foil and the blackened copper foil process to produce a new copper foil, namely the reverse blackened copper foil (RTF-B copper foil), which is a new improvement to the production operation and process.

[0007] The present invention provides a reverse electrolytic copper foil electroplating blackening method, comprising the following steps:

[0008] S1: After pre-treating the ultra-low profile copper foil, roughening and curing the smooth surface to obtain an ultra-low profile copper foil having a treated surface;

[0009] The roughening and curing treatment includes roughening treatment and curing treatment; both the roughening and curing treatments are carried out by acid sulfate copper plating process; roughening refers to electroplating to generate new grains on the basis of the original foil, such as Figure 2 and Figure 3 As shown; solidification refers to solidifying the newly formed grains on the basis of coarsening to prevent them from falling off.

[0010] S2: performing blackening electroplating on the treated surface of the ultra-low profile copper foil to complete the reverse electrolytic copper foil blackening method; during the blackening electroplating, the plating solution contains nickel ions, copper ions, potassium pyrophosphate, zinc ions and cobalt ions.

[0011] Preferably, in step S1, the pretreatment method is to pickle the surface of the ultra-low profile copper foil to remove oxides on the surface of the raw copper foil.

[0012] Preferably, in step S1, during the roughening treatment, the concentration of copper ions is 8-15 g / L, the concentration of sulfuric acid is 160-200 g / L, the temperature is 22-40°C, and the current density is 1500-2000 A / m 2 .

[0013] Preferably, in step S1, during the curing treatment, the concentration of copper ions is 30-70 g / L, the concentration of sulfuric acid is 80-130 g / L, the temperature is 30-50°C, and the current density is 1000-1500 A / m 2 .

[0014] Preferably, in step S1, the roughening treatment and the curing treatment are performed three times each.

[0015] Preferably, in step S2, the pH of the electroplating blackening solution is 9-10.

[0016] Preferably, in step S2, during blackening electroplating, the flow rate is 5-8m 3 / h.

[0017] Preferably, in step S2, during the blackening electroplating, the current density is 100-500A / m 2 .

[0018] Preferably, in step S2, the temperature during blackening electroplating is 25-30°C.

[0019] Preferably, in step S2, during the blackening electroplating, the concentration of nickel ions in the plating solution is 5-12 g / L, the concentration of copper ions is 2-3 g / L, the concentration of potassium pyrophosphate is 50-70 g / L, the concentration of zinc ions is 1-2 g / L, and the concentration of cobalt ions is 0.5-1 g / L.

[0020] First, select the ultra-low profile copper foil, pickle the surface of the copper foil to remove the surface oxide of the copper foil raw foil, reverse the smooth and rough surfaces of the ultra-low profile copper foil, and convert the rough surface of the traditional electrolytic copper foil to roughen and solidify the smooth surface. Generally, it undergoes three roughening and three solidification, that is, on the basis of the original bottom profile copper foil, the smooth surface of the copper foil is electroplated again, so that new copper buds grow on the basis of the original copper grains, so that the smooth surface is roughened to varying degrees. The degree of roughening is related to the concentration of the electroplating solution and the current density. Then, the treated surface is blackened and electroplated, wherein:

[0021] The main elements of the electroplating blackening solution are nickel, cobalt and copper. The concentration of nickel ions is controlled at 5-12g / L, copper ions at 2-3g / L, potassium pyrophosphate at 50-70g / L, zinc ions at 1-2g / L and cobalt ions at 0.5-1g / L. Potassium hydroxide is used to adjust the pH value of the electroplating solution to between 9 and 10. The flow rate of the electroplating solution is controlled at 5-8m 3 / h, current density 100-500A / m 2 , the temperature is 25-30℃, and the blackening electroplating is completed. The flow rate and current density can be slightly adjusted according to the target color.

[0022] The technical solution of the present invention has the following advantages over the prior art:

[0023] The blackening principle is:

[0024] The difficulty of blackening the reverse copper foil is:

[0025] 1. The roughness of the reverse copper foil treatment surface is low, generally below 2μm, which places high requirements on the equipment and personnel operation skills of the post-processing machine;

[0026] 2. Blackening electroplating is performed on the treated surface of the reverse copper foil. Because the treated surface has a low roughness, it is difficult to control the uniformity of the foil surface during electroplating. The concentration of the plating solution and the current density need to be closely combined to achieve the desired results.

[0027] A layer of black skin is plated on the surface of the original copper foil treatment surface, and it is ensured that this layer of black skin has no effect on the performance of the copper foil, and only the appearance of the copper foil is improved. The key elements are nickel, cobalt and copper, and suitable reagents are selected to form an alloy under the action of overpotential, rather than layered electroplating on the surface of the grains. This is also the key to ensuring uniform black plating. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The present invention is a process flow chart of the reverse electrolytic copper foil blackening method.

[0029] Figure 2This is a scanning electron microscope image of the reverse electrolytic copper foil of the present invention before roughening.

[0030] Figure 3 This is a scanning electron microscope image of the reverse electrolytic copper foil after roughening of the present invention. DETAILED DESCRIPTION

[0031] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0032] Example 1

[0033] Firstly, an ultra-low profile copper foil is selected, and the surface of the copper foil is washed with sulfuric acid to remove the surface oxide of the copper foil, the smooth surface and the rough surface of the ultra-low profile copper foil are reversed, and the rough surface of the traditional electrolytic copper foil is converted to the smooth surface for roughening and curing. After three roughening and three curing, the smooth surface of the copper foil is electroplated again on the basis of the original low profile copper foil, so that new copper buds grow on the basis of the original copper grains, so that the smooth surface is roughened to varying degrees.

[0034] During the roughening treatment, the concentration of copper ions was 10 g / L, the concentration of sulfuric acid was 180 g / L, the temperature was 30°C, and the current density of the roughening was 1500-2000 A / m 2 During the curing treatment, the concentration of copper ions is 50g / L, the concentration of sulfuric acid is 100g / L, the temperature is 40°C, and the curing current density is 1000-1500A / m 2 .

[0035] Then, the treated surface is subjected to blackening electroplating, wherein:

[0036] The main components of the electroplating blackening solution are nickel, cobalt and copper. The concentration of nickel ions is controlled at 8g / L, copper ions at 2g / L, potassium pyrophosphate at 60g / L, zinc ions at 1g / L and cobalt ions at 0.5g / L. Potassium hydroxide is used to adjust the pH value of the electroplating solution to 9. The flow rate of the electroplating solution is controlled at 5m 3 / h, current density 100A / m 2 , the temperature is 25℃, and the blackening electroplating is completed. The flow rate and current density can be finely adjusted according to the target color.

[0037] After the blackening electroplating, the copper foil is ashed, passivated, and dried in an oven before being taken out to complete the reverse electrolytic copper foil blackening method.

[0038] Example 2

[0039] Firstly, an ultra-low profile copper foil is selected, and the surface of the copper foil is washed with sulfuric acid to remove the surface oxide of the copper foil, the smooth surface and the rough surface of the ultra-low profile copper foil are reversed, and the rough surface of the traditional electrolytic copper foil is converted to the smooth surface for roughening and curing. After three roughening and three curing, the smooth surface of the copper foil is electroplated again on the basis of the original low profile copper foil, so that new copper buds grow on the basis of the original copper grains, so that the smooth surface is roughened to varying degrees.

[0040] During the roughening treatment, the concentration of copper ions was 8 g / L, the concentration of sulfuric acid was 160 g / L, the temperature was 22°C, and the current density of the roughening was 1500-2000 A / m 2 During the curing treatment, the concentration of copper ions is 30g / L, the concentration of sulfuric acid is 80g / L, the temperature is 30°C, and the curing current density is 1000-1500A / m 2 .

[0041] Then, the treated surface is subjected to blackening electroplating, wherein:

[0042] The main components of the electroplating blackening solution are nickel, cobalt and copper. The concentration of nickel ions is controlled at 5g / L, the concentration of copper ions is 2g / L, the concentration of potassium pyrophosphate is 50g / L, the concentration of zinc ions is 1g / L, and the concentration of cobalt ions is 0.5g / L. Potassium hydroxide is used to adjust the pH value of the electroplating solution to 9, and the flow rate of the electroplating solution is controlled at 5m 3 / h, current density 100A / m 2 , the temperature is 25℃, and the blackening electroplating is completed. The flow rate and current density can be finely adjusted according to the target color.

[0043] After the blackening electroplating, the copper foil is ashed, passivated, and dried in an oven before being taken out to complete the reverse electrolytic copper foil blackening method.

[0044] Example 3

[0045] Firstly, an ultra-low profile copper foil is selected, and the surface of the copper foil is washed with sulfuric acid to remove the surface oxide of the copper foil, the smooth surface and the rough surface of the ultra-low profile copper foil are reversed, and the rough surface of the traditional electrolytic copper foil is converted to the smooth surface for roughening and curing. After three roughening and three curing, the smooth surface of the copper foil is electroplated again on the basis of the original low profile copper foil, so that new copper buds grow on the basis of the original copper grains, so that the smooth surface is roughened to varying degrees.

[0046] During the roughening treatment, the concentration of copper ions was 15 g / L, the concentration of sulfuric acid was 200 g / L, the temperature was 40°C, and the current density of the roughening was 1500-2000 A / m 2During the curing treatment, the concentration of copper ions was 70g / L, the concentration of sulfuric acid was 130g / L, the temperature was 50°C, and the curing current density was 1000-1500A / m 2 .

[0047] Then, the treated surface is subjected to blackening electroplating, wherein:

[0048] The main components of the electroplating blackening solution are nickel, cobalt and copper. The concentration of nickel ions is controlled at 12g / L, copper ions at 3g / L, potassium pyrophosphate at 70g / L, zinc ions at 2g / L and cobalt ions at 1g / L. Potassium hydroxide is used to adjust the pH value of the electroplating solution to 10, and the flow rate of the electroplating solution is controlled at 8m 3 / h, current density 500A / m 2 , the temperature is 30℃, and the blackening electroplating is completed. The flow rate and current density can be finely adjusted according to the target color.

[0049] After the blackening electroplating, the copper foil is ashed, passivated, and dried in an oven before being taken out to complete the reverse electrolytic copper foil blackening method.

[0050] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A method for reverse electrolytic copper foil electroplating blackening, characterized in that: The steps include: S1: After pre-treating the ultra-low profile copper foil, roughening and curing the smooth surface to obtain an ultra-low profile copper foil having a treated surface; The roughening and curing treatment includes a roughening treatment and a curing treatment; the roughening treatment and the curing treatment are both performed using an acid sulfate copper plating process; S2: performing blackening electroplating on the treated surface of the ultra-low profile copper foil to complete the reverse electrolytic copper foil blackening method; during the blackening electroplating, the plating solution contains nickel ions, copper ions, potassium pyrophosphate, zinc ions and cobalt ions.

2. The reverse electrolytic copper foil blackening method according to claim 1, characterized in that: In the step S1, the pretreatment method is to pickle the surface of the ultra-low profile copper foil to remove the oxide on the surface of the raw copper foil.

3. The reverse electrolytic copper foil blackening method according to claim 1, characterized in that: In step S1, during the roughening treatment, the concentration of copper ions is 8-15 g / L, the concentration of sulfuric acid is 160-200 g / L, the temperature is 22-40°C, and the current density is 1500-2000 A / m 2 .

4. The reverse electrolytic copper foil blackening method according to claim 1, characterized in that: In step S1, during the curing treatment, the concentration of copper ions is 30-70 g / L, the concentration of sulfuric acid is 80-130 g / L, the temperature is 30-50°C, and the current density is 1000-1500 A / m 2 .

5. The reverse electrolytic copper foil blackening method according to claim 1, characterized in that: In the step S1, the roughening treatment and the curing treatment are both performed three times.

6. The reverse electrolytic copper foil blackening method according to claim 1, characterized in that: In step S2, the pH of the electroplating blackening solution is 9-10.

7. The reverse electrolytic copper foil blackening method according to claim 1, characterized in that: In step S2, during blackening electroplating, the flow rate is 5-8m 3 / h.

8. The reverse electrolytic copper foil blackening method according to claim 1, characterized in that: In step S2, during the blackening electroplating, the current density is 100-500A / m 2 .

9. The reverse electrolytic copper foil blackening method according to claim 1, characterized in that: In the step S2, the temperature during blackening electroplating is 25-30°C.

10. The reverse electrolytic copper foil blackening method according to claim 1, characterized in that: In step S2, during blackening electroplating, the concentration of nickel ions in the plating solution is 5-12 g / L, the concentration of copper ions is 2-3 g / L, the concentration of potassium pyrophosphate is 50-70 g / L, the concentration of zinc ions is 1-2 g / L, and the concentration of cobalt ions is 0.5-1 g / L.

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