A high-ductility electrolytic copper foil and its preparation method

Abstract

The present invention belongs to the technical field of electrolytic copper foil, and discloses a high-ductility electrolytic copper foil and a preparation method thereof. The present invention adds additives to a basic electrolyte, heats the temperature to the electrolysis temperature, and performs electrolysis to obtain a raw foil; the raw foil is immersed in an anti-oxidation liquid for anti-oxidation treatment to obtain a high-ductility electrolytic copper foil. The additives of the present invention include polyethylene glycol, polyethyleneimine, sodium saccharin, sodium polydisulfide dipropane sulfonate, methyl cellulose, and rare earth metal salts. The present invention regulates the types of additives in the electrolytic preparation process of the raw foil, regulates the surface morphology of the copper foil, reduces the surface roughness, improves its ductility, and combines with anti-oxidation treatment to form a protective layer on the surface of the copper foil, so that the prepared electrolytic copper foil has good high-temperature ductility, is not easily oxidized and discolored after processing under high temperature conditions, and has a high-temperature elongation greater than 12%, thereby preventing the copper foil from cracking after processing.

Description

Technical Field

[0001] The present invention relates to the technical field of electrolytic copper foil, and in particular to a high-ductility electrolytic copper foil and a preparation method thereof. Background Art

[0002] Copper-clad laminates, as the substrate material used in printed circuit board (PCB) manufacturing, primarily provide interconnection, insulation, and support for the PCB. They significantly impact the signal transmission speed, energy loss, and characteristic impedance of the circuit. Therefore, the performance, quality, processability, manufacturing level, manufacturing cost, and long-term reliability and stability of the PCB depend heavily on the copper-clad laminates. Copper-clad laminates are typically made by impregnating electronic fiberglass cloth or other reinforcing materials with resin, coating one or both sides with copper foil, and then hot-pressing. The copper foil is the key component.

[0003] With the development of technology, electronic devices are developing in the direction of lightweight, miniaturization and thinness, and higher quality and performance requirements are placed on the electrolytic copper foil used for copper clad laminates. However, at present, high-performance electrolytic copper foil mainly relies on imports, which greatly restricts the rapid development of electronic technology. Moreover, the process of preparing copper clad laminates with electrolytic copper foil is usually carried out under high temperature and high pressure conditions, which requires the copper foil to have good high-temperature elongation properties. Existing electrolytic copper foil is produced by electrolysis of copper sulfate solution. The process parameters in the electrolysis process, such as copper ion concentration, sulfuric acid concentration, current density, etc., will affect the micromorphology and performance of the electrolytic copper foil. Researchers use different additives in the electrolyte to control the surface roughness and performance of the electrolytic copper foil. However, the existing electrolytic copper foil is prone to oxidation, discoloration or fracture under certain processing conditions, and the high-temperature ductility still cannot meet expectations.

[0004] Therefore, how to obtain highly ductile electrolytic copper foil is a technical problem that needs to be solved urgently. Summary of the Invention

[0005] The object of the present invention is to provide a high-ductility electrolytic copper foil and a preparation method thereof, so as to solve the problem that the existing electrolytic copper foil has poor ductility under high temperature conditions.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing a high-ductility electrolytic copper foil, comprising the following steps:

[0008] (1) Adding additives to the basic electrolyte, heating it to the electrolysis temperature, and performing electrolysis to obtain a raw foil;

[0009] (2) soaking the raw foil in an anti-oxidation solution for anti-oxidation treatment to obtain a highly ductile electrolytic copper foil;

[0010] Wherein, the additives in step (1) include polyethylene glycol, polyethyleneimine, saccharin sodium, polydisulfide dipropylene sulfonate sodium, methyl cellulose, and rare earth metal salts.

[0011] Preferably, in the above-mentioned method for preparing a high ductility electrolytic copper foil, the concentration of the additives in the basic electrolyte in step (1) is: polyethylene glycol 30-60 mg / L, polyethyleneimine 50-80 mg / L, saccharin sodium 0.1-10 mg / L, polydisulfide dipropylene glycol sodium sulfonate 20-40 mg / L, methyl cellulose 20-70 mg / L, and rare earth metal salt 1-15 mg / L.

[0012] Preferably, in the above-mentioned method for preparing a high-ductility electrolytic copper foil, the rare earth metal salt in step (1) is one or more of nitrate, sulfate, and acetate; the rare earth metal in the rare earth metal salt is one or more of yttrium, lanthanum, cerium, neodymium, and samarium.

[0013] Preferably, in the above-mentioned method for preparing a high-ductility electrolytic copper foil, the basic electrolyte in step (1) is: 80-95 g / L copper ions, 100-140 g / L sulfuric acid, and 10-20 mg / L chloride ions.

[0014] Preferably, in the above-mentioned method for preparing a high ductility electrolytic copper foil, the electrolysis conditions in step (1) are: a temperature of 50 to 70°C, a current density of 50 to 100 A / dm 2 .

[0015] Preferably, in the above-mentioned method for preparing a high-ductility electrolytic copper foil, the anti-oxidation liquid in step (2) is: 3-5 g / L of glucose, 0.5-3 g / L of benzimidazole, 1-2 g / L of 2-mercaptobenzimidazole, and 2-4 g / L of polyacrylic acid.

[0016] Preferably, in the above-mentioned method for preparing a high-ductility electrolytic copper foil, the time of the anti-oxidation treatment in step (2) is 5 to 20 seconds; the temperature of the anti-oxidation treatment is 30 to 45°C.

[0017] The present invention also provides a high-ductility electrolytic copper foil prepared by a method for preparing the high-ductility electrolytic copper foil.

[0018] It can be seen from the above technical solutions that compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention regulates the types of additives in the electrolytic preparation process of raw foil, regulates the surface morphology of the copper foil, reduces surface roughness, improves its ductility, and combines anti-oxidation treatment to form a protective layer on the surface of the copper foil. The prepared electrolytic copper foil has good high-temperature ductility, is not easily oxidized and discolored after processing under high-temperature conditions, and has a high-temperature elongation of greater than 12%, thereby preventing cracks in the copper foil after processing. DETAILED DESCRIPTION

[0020] The present invention provides a method for preparing a high-ductility electrolytic copper foil, comprising the following steps:

[0021] (1) Adding additives to the basic electrolyte, heating it to the electrolysis temperature, and performing electrolysis to obtain a raw foil;

[0022] (2) soaking the raw foil in an anti-oxidation solution for anti-oxidation treatment to obtain a highly ductile electrolytic copper foil;

[0023] Wherein, the additives in step (1) include polyethylene glycol, polyethyleneimine, saccharin sodium, polydisulfide dipropylene sulfonate sodium, methyl cellulose, and rare earth metal salts.

[0024] In the present invention, the concentration of the additives in the basic electrolyte in step (1) is preferably: polyethylene glycol 30-60 mg / L, polyethyleneimine 50-80 mg / L, saccharin sodium 0.1-10 mg / L, polydisulfide dipropylene glycol sodium sulfonate 20-40 mg / L, methyl cellulose 20-70 mg / L, and rare earth metal salt 1-15 mg / L.

[0025] Preferably, the concentration of polyethylene glycol is further preferably 33-54 mg / L, more preferably 48 mg / L; the concentration of polyethyleneimine is further preferably 57-76 mg / L, more preferably 68 mg / L; the concentration of saccharin sodium is further preferably 0.7-6.7 mg / L, more preferably 4.2 mg / L; the concentration of sodium polydisulfide propane sulfonate is further preferably 23-38 mg / L, more preferably 31 mg / L; the concentration of methylcellulose is further preferably 28-62 mg / L, more preferably 54 mg / L; and the concentration of rare earth metal salt is further preferably 4-13 mg / L, more preferably 9 mg / L.

[0026] In the present invention, the rare earth metal salt in step (1) is preferably one or more of nitrate, sulfate, and acetate, more preferably one or two of nitrate and sulfate, and more preferably sulfate; the rare earth metal in the rare earth metal salt is preferably one or more of yttrium, lanthanum, cerium, neodymium, and samarium, more preferably one or more of yttrium, lanthanum, cerium, and neodymium, and more preferably cerium.

[0027] In the present invention, the basic electrolyte in step (1) is preferably: 80-95 g / L copper ions, 100-140 g / L sulfuric acid, and 10-20 mg / L chloride ions.

[0028] Preferably, the concentration of copper ions is further preferably 84-91 g / L, more preferably 88 g / L; the concentration of sulfuric acid is further preferably 112-132 g / L, more preferably 127 g / L; the concentration of chloride ions is further preferably 12-17 mg / L, more preferably 14 mg / L.

[0029] In the present invention, the electrolysis conditions in step (1) are preferably: a temperature of 50 to 70°C, a current density of 50 to 100 A / dm 2 .

[0030] As a preferred embodiment, the temperature is further preferably 53 to 67°C, more preferably 62°C; the current density is further preferably 64 to 85 A / dm 2 , more preferably 76A / dm 2 .

[0031] In the present invention, the antioxidant solution in step (2) preferably contains: 3-5 g / L glucose, 0.5-3 g / L benzimidazole, 1-2 g / L 2-mercaptobenzimidazole, and 2-4 g / L polyacrylic acid.

[0032] Preferably, the concentration of glucose is further preferably 3.3-4.7 g / L, more preferably 4.2 g / L; the concentration of benzimidazole is further preferably 0.9-2.1 g / L, more preferably 1.8 g / L; the concentration of 2-mercaptobenzimidazole is further preferably 1.2-1.8 g / L, more preferably 1.6 g / L; the concentration of polyacrylic acid is further preferably 2.3-3.7 g / L, more preferably 3.2 g / L.

[0033] In the present invention, the time of the anti-oxidation treatment in step (2) is preferably 5 to 20 seconds, more preferably 8 to 16 seconds, and more preferably 13 seconds; the temperature of the anti-oxidation treatment is preferably 30 to 45°C, more preferably 33 to 41°C, and more preferably 38°C.

[0034] The present invention also provides a high-ductility electrolytic copper foil prepared by a method for preparing the high-ductility electrolytic copper foil.

[0035] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0036] Example 1

[0037] This embodiment provides a method for preparing a high-ductility electrolytic copper foil, comprising the following steps:

[0038] (1) The basic electrolyte is: copper ion 80 g / L, sulfuric acid 120 g / L, chloride ion 13 mg / L; additives are added to the basic electrolyte, and the concentrations of the additives in the basic electrolyte are: polyethylene glycol 32 mg / L, polyethyleneimine 54 mg / L, saccharin sodium 2 mg / L, polydisulfide dipropylene glycol sodium sulfonate 20 mg / L, methylcellulose 30 mg / L, cerium sulfate 5 mg / L;

[0039] The basic electrolyte solution with the additives was heated to 60°C and then powered on for electrolysis. The electrolysis conditions were: temperature 60°C, current density 55A / dm 2 , get raw foil;

[0040] (2) The raw foil was immersed in an anti-oxidation solution at 30°C for 8s for anti-oxidation treatment. The composition of the anti-oxidation solution was as follows: 3.1 g / L glucose, 0.9 g / L benzimidazole, 1 g / L 2-mercaptobenzimidazole, and 2.2 g / L polyacrylic acid to obtain a high ductility electrolytic copper foil.

[0041] The thickness of the electrolytic copper foil prepared above is 18 μm, and the roughness of the matte surface is 2.23 μm. The tensile strength and elongation at high temperature (180°C for 5 minutes) are measured according to GB / T29847-2013. The high-temperature tensile strength is 192 MPa, and the high-temperature elongation is 12.8%.

[0042] Example 2

[0043] This embodiment provides a method for preparing a high-ductility electrolytic copper foil, comprising the following steps:

[0044] (1) The basic electrolyte is: copper ion 85 g / L, sulfuric acid 110 g / L, chloride ion 16 mg / L; additives are added to the basic electrolyte, and the concentrations of the additives in the basic electrolyte are: polyethylene glycol 50 mg / L, polyethyleneimine 70 mg / L, saccharin sodium 6 mg / L, polydisulfide dipropane sulfonate sodium 25 mg / L, methyl cellulose 30 mg / L, and lanthanum nitrate 1 mg / L;

[0045] The basic electrolyte solution with the additives was heated to 50°C and then powered on for electrolysis. The electrolysis conditions were: temperature 50°C, current density 60A / dm 2 , get raw foil;

[0046] (2) The raw foil was immersed in an anti-oxidation solution at 30°C for 10 seconds for anti-oxidation treatment. The composition of the anti-oxidation solution was as follows: 3.6 g / L glucose, 1.2 g / L benzimidazole, 1.2 g / L 2-mercaptobenzimidazole, and 3.3 g / L polyacrylic acid to obtain a high ductility electrolytic copper foil.

[0047] The thickness of the electrolytic copper foil prepared above is 18 μm, and the roughness of the matte surface is 2.17 μm. The tensile strength and elongation at high temperature (180°C for 5 minutes) are measured according to GB / T29847-2013. The high-temperature tensile strength is 184 MPa, and the high-temperature elongation is 13.7%.

[0048] Example 3

[0049] This embodiment provides a method for preparing a high-ductility electrolytic copper foil, comprising the following steps:

[0050] (1) The basic electrolyte is: copper ion 90 g / L, sulfuric acid 120 g / L, chloride ion 18 mg / L; additives are added to the basic electrolyte, and the concentrations of the additives in the basic electrolyte are: polyethylene glycol 40 mg / L, polyethyleneimine 60 mg / L, saccharin sodium 4 mg / L, polydisulfide dipropylene glycol sodium sulfonate 32 mg / L, methylcellulose 55 mg / L, cerium nitrate 4 mg / L;

[0051] The basic electrolyte solution with the additives was heated to 65°C and then powered on for electrolysis. The electrolysis conditions were: temperature 65°C, current density 70A / dm 2 , get raw foil;

[0052] (2) The raw foil was immersed in an anti-oxidation solution at 35°C for 13 seconds for anti-oxidation treatment. The composition of the anti-oxidation solution was as follows: 4.2 g / L glucose, 2.5 g / L benzimidazole, 1.4 g / L 2-mercaptobenzimidazole, and 3.5 g / L polyacrylic acid to obtain a high ductility electrolytic copper foil.

[0053] The thickness of the electrolytic copper foil prepared above is 18 μm, and the roughness of the matte surface is 2.31 μm. The tensile strength and elongation at high temperature (180°C for 5 minutes) are measured according to GB / T29847-2013. The high-temperature tensile strength is 208 MPa, and the high-temperature elongation is 14.4%.

[0054] Example 4

[0055] This embodiment provides a method for preparing a high-ductility electrolytic copper foil, comprising the following steps:

[0056] (1) The basic electrolyte is: copper ion 90 g / L, sulfuric acid 140 g / L, chloride ion 12 mg / L; additives are added to the basic electrolyte, and the concentrations of the additives in the basic electrolyte are: polyethylene glycol 50 mg / L, polyethyleneimine 70 mg / L, saccharin sodium 8 mg / L, polydisulfide dipropylene glycol sodium sulfonate 32 mg / L, methylcellulose 55 mg / L, cerium sulfate 10 mg / L;

[0057] The basic electrolyte solution with the additives was heated to 60°C and then powered on for electrolysis. The electrolysis conditions were: temperature 60°C, current density 80A / dm 2 , get raw foil;

[0058] (2) The raw foil was immersed in an anti-oxidation solution at 40°C for 15 seconds for anti-oxidation treatment. The composition of the anti-oxidation solution was as follows: 4.5 g / L glucose, 1.7 g / L benzimidazole, 1.8 g / L 2-mercaptobenzimidazole, and 3.3 g / L polyacrylic acid to obtain a high ductility electrolytic copper foil.

[0059] The thickness of the electrolytic copper foil prepared above is 18 μm, and the roughness of the matte surface is 2.26 μm. The tensile strength and elongation at high temperature (180°C for 5 minutes) are measured according to GB / T29847-2013. The high-temperature tensile strength is 176 MPa, and the high-temperature elongation is 12.3%.

[0060] Example 5

[0061] This embodiment provides a method for preparing a high-ductility electrolytic copper foil, comprising the following steps:

[0062] (1) The basic electrolyte is: copper ion 95g / L, sulfuric acid 140g / L, chloride ion 18mg / L; additives are added to the basic electrolyte, and the concentrations of the additives in the basic electrolyte are: polyethylene glycol 60mg / L, polyethyleneimine 60mg / L, saccharin sodium 7mg / L, poly (sodium disulfide propane sulfonate) 38mg / L, methyl cellulose 50mg / L, and lanthanum nitrate 12mg / L;

[0063] The basic electrolyte solution with the additives was heated to 70°C and then powered for electrolysis. The electrolysis conditions were: temperature 70°C, current density 90A / dm 2 , get raw foil;

[0064] (2) The raw foil was immersed in an anti-oxidation solution at 45°C for 17 seconds for anti-oxidation treatment. The composition of the anti-oxidation solution was: 5 g / L glucose, 2.6 g / L benzimidazole, 2 g / L 2-mercaptobenzimidazole, and 3.7 g / L polyacrylic acid to obtain a high ductility electrolytic copper foil.

[0065] The thickness of the electrolytic copper foil prepared above is 18 μm, and the roughness of the matte surface is 2.19 μm. The tensile strength and elongation at high temperature (180°C for 5 minutes) are measured according to GB / T29847-2013. The high-temperature tensile strength is 196 MPa and the high-temperature elongation is 13.5%.

[0066] Comparative Example 1

[0067] This comparative example provides a method for preparing an electrolytic copper foil. For details, refer to Example 5, except that the additive does not contain sodium saccharin and lanthanum nitrate.

[0068] The thickness of the electrolytic copper foil prepared above is 18 μm, and the roughness of the matte surface is 2.57 μm. The tensile strength and elongation at high temperature (180°C for 5 minutes) are measured according to GB / T29847-2013. The high-temperature tensile strength is 146 MPa and the high-temperature elongation is 8.7%.

[0069] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing a high ductility electrolytic copper foil, characterized in that: The following steps are involved: (1) Adding additives to the basic electrolyte, heating it to the electrolysis temperature, and performing electrolysis to obtain a raw foil; (2) soaking the raw foil in an anti-oxidation solution for anti-oxidation treatment to obtain a highly ductile electrolytic copper foil; Wherein, the additives in step (1) include polyethylene glycol, polyethyleneimine, sodium saccharin, sodium polydisulfide dipropane sulfonate, methylcellulose, and rare earth metal salts; The concentrations of the additives in the basic electrolyte in step (1) are: polyethylene glycol 30-60 mg / L, polyethyleneimine 50-80 mg / L, saccharin sodium 0.1-10 mg / L, polydisulfide dipropylene sulfonate sodium 20-40 mg / L, methyl cellulose 20-70 mg / L, and rare earth metal salt 1-15 mg / L.

2. The method for preparing a high ductility electrolytic copper foil according to claim 1, wherein: The rare earth metal salt in step (1) is one or more of nitrate, sulfate, and acetate; the rare earth metal in the rare earth metal salt is one or more of yttrium, lanthanum, cerium, neodymium, and samarium.

3. The method for preparing a high ductility electrolytic copper foil according to claim 1, wherein: The basic electrolyte in step (1) is: 80-95 g / L copper ions, 100-140 g / L sulfuric acid, and 10-20 mg / L chloride ions.

4. The method for preparing a high ductility electrolytic copper foil according to claim 2, wherein: The electrolysis conditions in step (1) are: temperature of 50-70°C, current density of 50-100A / dm 2 .

5. The method for preparing a high ductility electrolytic copper foil according to claim 1 or 4, characterized in that: The anti-oxidation liquid in step (2) is: 3-5 g / L glucose, 0.5-3 g / L benzimidazole, 1-2 g / L 2-mercaptobenzimidazole, and 2-4 g / L polyacrylic acid.

6. The method for preparing a high ductility electrolytic copper foil according to claim 5, wherein: The time of the anti-oxidation treatment in step (2) is 5 to 20 seconds; the temperature of the anti-oxidation treatment is 30 to 45°C.

7. A high-ductility electrolytic copper foil prepared by the method for preparing a high-ductility electrolytic copper foil according to any one of claims 1 to 6.