A method for preparing rolled copper foil and rolled copper foil

Abstract

This invention relates to a method for preparing rolled copper foil and the rolled copper foil itself. The method for preparing rolled copper foil includes the following steps: smelting: during the smelting process, Sn and P elements are added to the copper solution. After smelting, the Sn content in the solution is 0.10–0.12 wt%, and the P content is 0.01–0.05 wt%. Using the preparation method of this invention, the bending resistance of the rolled copper foil can be significantly improved.

Description

Technical Field

[0001] This invention relates to the field of copper foil technology, and in particular to a method for preparing rolled copper foil and the rolled copper foil itself. Background Technology

[0002] With the rapid development of electronic devices, which are increasingly trending towards lighter, thinner, and faster designs, rolled copper foil, as an indispensable basic material for manufacturing printed circuit boards (PCBs), copper-clad laminates (FCCLs), and lithium-ion batteries, is seeing a growing demand in aerospace equipment, aircraft instruments, mobile phones, military equipment, and everyday electronic devices. Rolled copper foil, based on its excellent ductility, bending resistance, and conductivity, undergoes various surface treatments to achieve superior oxidation resistance. However, with the continuous development of related industries, even higher requirements are being placed on copper foil.

[0003] Especially regarding the folding resistance of copper foil, its inherent physical properties and manufacturing process limitations make it prone to breakage and cracking during bending and folding operations, severely impacting product quality and lifespan. Therefore, developing a manufacturing process that can significantly improve the folding resistance of copper foil is of great significance for enhancing the overall level of the electronics industry. Summary of the Invention

[0004] In view of the above problems, the present invention is proposed to provide a method for preparing rolled copper foil and rolled copper foil that overcomes or at least partially solves the above problems, and can solve the problem of poor folding resistance of existing rolled copper foil.

[0005] Specifically, the present invention provides a method for preparing rolled copper foil, comprising the following steps:

[0006] Smelting: Sn and P elements are added to the copper solution during the smelting process. After smelting, the Sn content in the solution is 0.10-0.12 wt% and the P content is 0.01-0.05 wt%.

[0007] Optionally, in the smelting step, the solution after smelting also contains the following components:

[0008] Cu+Ag≥99.85wt%;

[0009] S≤0.0015wt%;

[0010] Fe ≤ 0.001 wt%;

[0011] Zn≤0.0001wt%;

[0012] Bi ≤ 0.0001 wt%;

[0013] Sb≤0.0004wt%;

[0014] Ni ≤ 0.001 wt%;

[0015] Pb ≤ 0.0005 wt%;

[0016] O ≤ 0.0005 wt%.

[0017] Optionally, the Sn content is 0.11–0.12 wt%; and / or

[0018] The content of phosphorus (P) is 0.031–0.05 wt%.

[0019] Optionally, after the smelting step, the method for preparing rolled copper foil may further include the following steps in sequence: casting, hot rolling, milling, rough rolling, intermediate rolling, finish rolling, and foil rolling.

[0020] Optionally, in the casting step: a semi-continuous casting method is used, the casting temperature is controlled at 900℃~1100℃, and the temperature is held for 2 hours. After casting is completed, an ingot is obtained.

[0021] Optionally, in the hot rolling step: the initial rolling temperature is 850°C, the final rolling temperature is not lower than 500°C, and after multiple rolling passes, a slab with a thickness of 20 mm is obtained; and / or

[0022] In the milling step: the slab obtained in the hot rolling step is milled to obtain a slab with a thickness of 16.0 mm; and / or

[0023] In the roughing rolling step: the slab obtained in the milling step is rolled into a 1.0 mm thick strip in multiple passes; and / or

[0024] In the intermediate rolling step: the strip obtained from the rough rolling step is annealed and then rolled in two passes to a thickness of 0.4 mm; and / or

[0025] In the finishing rolling step: the strip obtained in the intermediate rolling step is continuously annealed and then rolled into a copper strip with a thickness of 0.15 mm; and / or

[0026] In the foil rolling step: the copper strip obtained in the finishing rolling step is subjected to foil rolling treatment, which is divided into 5 to 7 rolling passes.

[0027] Optionally, the foil rolling process consists of the following six rolling passes:

[0028] First pass: entry thickness is 0.150mm, exit thickness is 0.097mm, reduction rate is 35.3%, total entry tension is 3500N, total exit tension is 5500N, rolling force is 450KN, rolling speed is 500m / min;

[0029] Second pass: The entry thickness is 0.097mm, the exit thickness is 0.066mm, the reduction rate is 31.9%, the total entry tension is 3100N, the total exit tension is 4100N, the rolling force is 450KN, and the rolling speed is 500m / min.

[0030] Third pass: The entry thickness is 0.066mm, the exit thickness is 0.045mm, the reduction rate is 31.8%, the total entry tension is 2600N, the total exit tension is 3200N, the rolling force is 450KN, and the rolling speed is 650m / min.

[0031] Fourth pass: The thickness on the inlet side is 0.045mm, the thickness on the outlet side is 0.032mm, the reduction rate is 28.9%, the total tension on the inlet side is 1700N, the total tension on the outlet side is 2100N, the rolling force is 450KN, and the rolling speed is 650m / min.

[0032] Fifth pass: entry thickness is 0.032mm, exit thickness is 0.023mm, reduction rate is 28.1%, total entry tension is 1000N, total exit tension is 1200N, rolling force is 450KN, rolling speed is 650m / min;

[0033] The sixth pass has an infeed thickness of 0.023 mm, an outfeed thickness of 0.018 mm, a reduction rate of 21.7%, a total infeed tension of 800 N, a total outfeed tension of 950 N, a rolling force of 450 KN, and a rolling speed of 650 m / min, resulting in a rolled copper foil with a thickness of 0.018 mm.

[0034] Optionally, after the foil rolling step, the method for preparing rolled copper foil further includes the following steps:

[0035] Electroplating: The surface of the rolled copper foil is subjected to electroplating treatment.

[0036] Optionally, the electroplating step includes:

[0037] Roughening treatment: Cu in the roughening solution 2+ The ion concentration was 40 g / L, the H₂SO₄ concentration was 120 g / L, and the current density was 55 A / dm². 2 ;

[0038] Curing treatment: Cu in the curing solution 2+ The ion concentration is 50 g / L, the H2SO4 concentration is 80 g / L, and the current density is 45 A / dm³. 2 ;

[0039] Surface zinc plating treatment: The concentration of ZnCl2 in the electroplating solution is 50 g / L, the concentration of KCl is 150 g / L, the concentration of boric acid is 25 g / L, the pH of the electroplating solution is 5, and the current density is 3 A / dm³. 2 .

[0040] On the other hand, the present invention also provides a rolled copper foil prepared by any of the above-described methods.

[0041] This invention involves adding a certain amount of Sn and P elements to the copper solution during the billet smelting process, resulting in a solution containing 0.10–0.12 wt% Sn and 0.01–0.05 wt% P. Sn, through solid solution strengthening, causes lattice distortion, increasing the resistance to dislocation movement and improving the strength and toughness of the rolled copper foil. This allows it to absorb more energy during bending, effectively improving the flexural strength of the copper foil. P refines the grains, reducing the grain size and increasing the grain boundary area of ​​the rolled copper foil. During bending, dislocation movement is hindered at the grain boundaries, which disperses stress, reduces crack formation, and improves flexural strength. Therefore, this invention can improve the flexural strength of rolled copper foil.

[0042] Furthermore, with a reasonable processing technology, the present invention can further improve the bending resistance of copper foil.

[0043] Furthermore, the present invention, through a reasonable surface treatment process, can improve the oxidation resistance of copper foil.

[0044] Furthermore, the rolled copper foil product prepared by this invention can withstand up to 639 bends.

[0045] The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0046] The following sections will describe some specific embodiments of the invention in detail by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or portions. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0047] Figure 1 This is a schematic flowchart of the method for preparing rolled copper foil in Example 1. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially. Furthermore, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, or solution B, or a solution where both A and B are satisfied simultaneously. In addition, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] This invention provides a method for preparing rolled copper foil, including a smelting step. Sn and P elements are added during the smelting step, and after smelting, the Sn content in the solution is 0.10–0.12 wt%, and the P content is 0.01–0.05 wt%.

[0050] Specifically, after the smelting step, the method for preparing rolled copper foil also includes casting and machining steps. wt% is a unit expressing weight percentage, used to indicate the mass proportion of a substance in a mixture. After smelting, the Sn content in the solution can be any one of 0.10wt%, 0.105wt%, 0.11wt%, 0.115wt%, or 0.12wt%, and the P content can be any one of 0.01wt%, 0.02wt%, 0.025wt%, 0.028wt%, 0.03wt%, 0.031wt%, 0.035wt%, 0.04wt%, 0.045wt%, 0.048wt%, or 0.05wt%.

[0051] In this embodiment, on the one hand, Sn element, through solid solution strengthening, causes lattice distortion, increasing the resistance to dislocation movement and improving the strength and toughness of the rolled copper foil. This allows it to absorb more energy during bending, thereby effectively improving the flexural strength of the copper foil. On the other hand, P element can refine the grains, making the grain size of the rolled copper foil smaller and increasing the grain boundary area. During bending, dislocation movement is hindered at the grain boundaries, which can disperse stress, reduce crack formation, and improve flexural strength. Therefore, in this embodiment, by adding a certain amount of Sn and P elements to the copper solution during the billet smelting process, so that the solution contains 0.10–0.12 wt% Sn and 0.01–0.05 wt% P, the flexural strength of the rolled copper foil can be improved.

[0052] In some optional embodiments of the present invention, after the smelting step is completed, the solution further contains the following components: Cu + Ag ≥ 99.85 wt%; S ≤ 0.0015 wt%; Fe ≤ 0.001 wt%; Zn ≤ 0.0001 wt%; Bi ≤ 0.0001 wt%; Sb ≤ 0.0004 wt%; Ni ≤ 0.001 wt%; Pb ≤ 0.0005 wt%; O ≤ 0.0005 wt%.

[0053] Specifically, after smelting, the Cu+Ag content in the solution can be any one of 99.855wt%, 99.86wt%, 99.87wt%, or 99.88wt%.

[0054] After smelting, the sulfur content in the solution can be any one of 0.0015wt%, 0.0014wt%, 0.0013wt%, 0.0012wt%, 0.0011wt%, 0.001wt%, 0.0009wt%, 0.0005wt%, or 0.0001wt%.

[0055] After smelting, the Fe content in the solution can be any one of 0.001wt%, 0.0009wt%, 0.0008wt%, 0.0007wt%, 0.0005wt%, 0.0004wt%, 0.0003wt%, or 0.0001wt%.

[0056] After smelting, the Zn content in the solution can be any one of 0.0001wt%, 0.00009wt%, 0.00008wt%, 0.00007wt%, 0.00005wt%, 0.00004wt%, 0.00003wt%, or 0.00001wt%.

[0057] After smelting, the Bi content in the solution can be any one of 0.0001wt%, 0.00009wt%, 0.00008wt%, 0.00007wt%, 0.00005wt%, 0.00004wt%, 0.00003wt%, or 0.00001wt%.

[0058] After smelting, the Sb content in the solution can be any one of 0.0004wt%, 0.0003wt%, 0.0002wt%, or 0.0001wt%.

[0059] After smelting, the Ni content in the solution can be any one of 0.001wt%, 0.0009wt%, 0.0008wt%, 0.0007wt%, 0.0006wt%, 0.0005wt%, 0.0003wt%, or 0.0001wt%.

[0060] After smelting, the Pb content in the solution can be any one of 0.0005wt%, 0.0004wt%, 0.0003wt%, 0.0002wt%, 0.0001wt%, 0.00009wt%, or 0.00001wt%.

[0061] After melting, the O content in the solution can be any one of 0.0005wt%, 0.0004wt%, 0.0003wt%, 0.0002wt%, 0.0001wt%, 0.00009wt%, or 0.00001wt%.

[0062] In this embodiment, since the smelting solution is a copper alloy solution, the resulting rolled copper foil is a copper alloy foil, which possesses characteristics such as high strength, high hardness, and high ductility. Furthermore, the content of impurity elements in the smelting solution is low, resulting in a relatively low content of these elements in the final rolled copper foil. This is beneficial for further improving alloy properties, enhancing mechanical properties, and reducing the tendency for hot cracking. In summary, this embodiment is beneficial for further improving the bending resistance of the rolled copper foil.

[0063] In some optional embodiments of the present invention, the Sn content is 0.11 to 0.12 wt%.

[0064] In some optional embodiments of the present invention, the content of P is 0.031 to 0.05 wt%.

[0065] In some optional embodiments of the present invention, after the smelting step, the method for preparing rolled copper foil further includes the following steps in sequence: casting, hot rolling, milling, rough rolling, intermediate rolling, finish rolling, and foil rolling.

[0066] Specifically, the copper alloy solution is processed into ingots through casting, the ingots are processed into slabs through hot rolling, the thickness of the slabs is reduced by milling, the slabs are processed into strips through rough rolling, the thickness of the strips is reduced through intermediate rolling and finish rolling, and the strips are processed into copper foils through foil rolling. Through the above processing steps, the mechanical properties of the rolled copper foil can be improved, thereby giving it good bending resistance.

[0067] In some optional embodiments of the present invention, in the casting step: a semi-continuous casting method is used, the casting temperature is controlled at 900℃~1100℃ (e.g., 900℃, 950℃, 960℃, 970℃, 980℃, 990℃, 1000℃, 1050℃, 1060℃, 1070℃, 1080℃, 1090℃ or 1100℃), and the temperature is held for 2 hours. After casting is completed, an ingot is obtained.

[0068] In some optional embodiments of the present invention, in the hot rolling step: the initial rolling temperature is 850°C, the final rolling temperature is not lower than 500°C, and after rolling multiple passes, a slab with a thickness of 20mm is obtained.

[0069] In some optional embodiments of the present invention, in the milling step: after the slab obtained in the hot rolling step is milled, a slab with a thickness of 16.0 mm is obtained.

[0070] In some alternative embodiments of the present invention, in the roughing step: the slab obtained in the milling step is rolled into a strip with a thickness of 1.0 mm in multiple passes.

[0071] In some optional embodiments of the present invention, in the intermediate rolling step: the strip obtained in the rough rolling step is annealed and then rolled into a 0.4 mm thick strip in two passes.

[0072] In some optional embodiments of the present invention, in the finishing rolling step: the strip obtained in the intermediate rolling step is continuously annealed and then rolled into a copper strip with a thickness of 0.15 mm.

[0073] In some optional embodiments of the present invention, in the foil rolling step: the copper strip obtained in the finishing rolling step is subjected to foil rolling treatment, which is divided into 5 to 7 rolling passes.

[0074] In some optional embodiments of the present invention, the foil rolling step is divided into the following 6 rolling passes:

[0075] First pass: entry thickness is 0.150mm, exit thickness is 0.097mm, reduction rate is 35.3%, total entry tension is 3500N, total exit tension is 5500N, rolling force is 450KN, rolling speed is 500m / min;

[0076] Second pass: The entry thickness is 0.097mm, the exit thickness is 0.066mm, the reduction rate is 31.9%, the total entry tension is 3100N, the total exit tension is 4100N, the rolling force is 450KN, and the rolling speed is 500m / min.

[0077] Third pass: The entry thickness is 0.066mm, the exit thickness is 0.045mm, the reduction rate is 31.8%, the total entry tension is 2600N, the total exit tension is 3200N, the rolling force is 450KN, and the rolling speed is 650m / min.

[0078] Fourth pass: The thickness on the inlet side is 0.045mm, the thickness on the outlet side is 0.032mm, the reduction rate is 28.9%, the total tension on the inlet side is 1700N, the total tension on the outlet side is 2100N, the rolling force is 450KN, and the rolling speed is 650m / min.

[0079] Fifth pass: entry thickness is 0.032mm, exit thickness is 0.023mm, reduction rate is 28.1%, total entry tension is 1000N, total exit tension is 1200N, rolling force is 450KN, rolling speed is 650m / min;

[0080] The sixth pass has an infeed thickness of 0.023 mm, an outfeed thickness of 0.018 mm, a reduction rate of 21.7%, a total infeed tension of 800 N, a total outfeed tension of 950 N, a rolling force of 450 KN, and a rolling speed of 650 m / min, resulting in a rolled copper foil with a thickness of 0.018 mm.

[0081] In some optional embodiments of the present invention, after the foil rolling step, the method for preparing rolled copper foil further includes an electroplating step to electroplat the surface of the rolled copper foil.

[0082] Electroplating can be used to form an electroplated layer on the surface of rolled copper foil, thereby giving the rolled copper foil good oxidation resistance.

[0083] In some alternative embodiments of the present invention, the electroplating step includes: roughening treatment, curing treatment and surface zinc plating treatment.

[0084] Furthermore, prior to the roughening process, a pretreatment step is included to clean the surface of the rolled copper foil, thereby improving the smoothness of the electroplated coating. The pretreatment step includes processes such as degreasing and pickling.

[0085] In some optional embodiments of the present invention, in the roughening step: Cu in the roughening solution 2+ The ion concentration was 40 g / L, the H₂SO₄ concentration was 120 g / L, and the current density was 55 A / dm². 2 .

[0086] In some optional embodiments of the present invention, in the curing step: Cu in the curing solution 2+ The ion concentration is 50 g / L, the H2SO4 concentration is 80 g / L, and the current density is 45 A / dm³. 2 .

[0087] In some optional embodiments of the present invention, in the surface zinc plating step: the concentration of ZnCl2 in the electroplating solution is 50 g / L, the concentration of KCl is 150 g / L, the concentration of boric acid is 25 g / L, the pH of the electroplating solution is 5, and the current density is 3 A / dm³. 2 .

[0088] This invention also provides a rolled copper foil, which is a rolled copper foil prepared by the rolled copper foil preparation method of any of the above embodiments.

[0089] The implementation scheme of this application will be described in detail below with reference to specific embodiments.

[0090] Example 1

[0091] like Figure 1 As shown, a method for preparing rolled copper foil includes the following steps:

[0092] (1) Smelting: Sn and P elements are added to the copper solution during the smelting process. After smelting, the solution contains the following components: Cu+Ag≥99.85wt%, S≤0.0015wt%, Fe≤0.001wt%, Zn≤0.0001wt%, Sn:0.10~0.12wt%, Bi≤0.0001wt%, Sb≤0.0004wt%, Ni≤0.001wt%, Pb≤0.0005wt%, O≤0.0005wt%, P:0.01~0.05wt%.

[0093] (2) Casting: Using a semi-continuous casting method, the casting temperature is controlled at 900℃~1100℃ and held for 2 hours. After casting, an ingot is obtained.

[0094] (3) Hot rolling: The initial rolling temperature is 850℃, and the final rolling temperature is not lower than 500℃. After rolling multiple passes, a slab with a thickness of 20mm is obtained.

[0095] (4) Milling: After milling the 20mm thick slab, a 16.0mm thick slab is obtained.

[0096] (5) Rough rolling: The 16.0mm thick slab is rolled into a 1.0mm thick strip in multiple passes.

[0097] (6) Intermediate rolling: After annealing, the 1.0 mm thick strip is rolled into a 0.4 mm thick strip in two passes.

[0098] (7) Finish rolling: The 0.4mm thick strip is continuously annealed and then rolled into a copper strip with a thickness of 0.15mm.

[0099] (8) Foil rolling: The copper strip is subjected to foil rolling, which is divided into 6 rolling passes.

[0100] First pass: entry thickness is 0.150mm, exit thickness is 0.097mm, reduction rate is 35.3%, total entry tension is 3500N, total exit tension is 5500N, rolling force is 450KN, and rolling speed is 500m / min.

[0101] Second pass: The entry thickness is 0.097mm, the exit thickness is 0.066mm, the reduction rate is 31.9%, the total entry tension is 3100N, the total exit tension is 4100N, the rolling force is 450KN, and the rolling speed is 500m / min.

[0102] Third pass: The entry thickness is 0.066mm, the exit thickness is 0.045mm, the reduction rate is 31.8%, the total entry tension is 2600N, the total exit tension is 3200N, the rolling force is 450KN, and the rolling speed is 650m / min.

[0103] Fourth pass: The entry thickness is 0.045mm, the exit thickness is 0.032mm, the reduction rate is 28.9%, the total entry tension is 1700N, the total exit tension is 2100N, the rolling force is 450KN, and the rolling speed is 650m / min.

[0104] Fifth pass: The entry thickness is 0.032mm, the exit thickness is 0.023mm, the reduction rate is 28.1%, the total entry tension is 1000N, the total exit tension is 1200N, the rolling force is 450KN, and the rolling speed is 650m / min.

[0105] The sixth pass has an infeed thickness of 0.023 mm, an outfeed thickness of 0.018 mm, a reduction rate of 21.7%, a total infeed tension of 800 N, a total outfeed tension of 950 N, a rolling force of 450 KN, and a rolling speed of 650 m / min, resulting in a rolled copper foil with a thickness of 0.018 mm.

[0106] (9) Electroplating treatment: Electroplating treatment is performed on the surface of the rolled copper foil to form a protective film on the surface of the rolled copper foil.

[0107] Electroplating includes the following steps:

[0108] Roughening treatment: Cu in the roughening solution 2+ The ion concentration was 40 g / L, the H₂SO₄ concentration was 120 g / L, and the current density was 55 A / dm². 2 .

[0109] Curing treatment: Cu in the curing solution 2+ The ion concentration is 50 g / L, the H2SO4 concentration is 80 g / L, and the current density is 45 A / dm³. 2 .

[0110] Surface zinc plating treatment: The concentration of ZnCl2 in the electroplating solution is 50 g / L, the concentration of KCl is 150 g / L, the concentration of boric acid is 25 g / L, the pH of the electroplating solution is 5, and the current density is 3 A / dm³. 2 .

[0111] (10) Cooling and drying: The electroplated rolled copper foil is cooled and then dried to obtain the final rolled copper foil product.

[0112] The performance of the rolled copper foil product prepared in this embodiment was tested:

[0113] (1) Copper foil folding endurance test

[0114] The MIT flexural strength test was conducted using an MIT flexural strength tester. The test used a 500g weight, a bending radius R = 0.8mm, and a bending angle of 135°. The test results showed that the rolled copper foil product could withstand up to 639 flexural cycles. Therefore, this invention can effectively improve the flexural strength of copper foil.

[0115] (2) Other performance tests

[0116] The rolled copper foil maintains over 90% of the international standard for conductivity (IACS) of annealed copper and achieves a strength of 550 MPa. In a 5% NaCl environment at 35°C, the rolled copper foil shows no corrosion after 24 hours. Therefore, the rolled copper foil in this embodiment possesses excellent comprehensive physical properties.

[0117] In summary, this embodiment provides a preparation process for improving the folding resistance of copper foil. By adding a certain amount of Sn and P elements during the smelting process of the billet, and then applying appropriate processing and surface treatment techniques, the folding resistance of the copper foil can be significantly improved. Specifically, Sn element, through solid solution strengthening, causes lattice distortion, increasing the resistance to dislocation movement and improving the strength and toughness of the copper foil. This allows it to absorb more energy during bending, thus effectively improving the folding resistance. P element refines the grains, reducing the grain size and increasing the grain boundary area. During bending, dislocation movement is hindered at the grain boundaries, which disperses stress, reduces crack formation, and improves folding resistance. Furthermore, surface electroplating treatment gives the rolled copper foil good anti-oxidation properties. Therefore, a rolled copper foil with excellent overall performance is ultimately obtained.

[0118] Comparative Example 1

[0119] The method for preparing rolled copper foil includes the following steps:

[0120] (1) Smelting: During the smelting process, a certain amount of O element is added to control the O content at 100-230ppm to obtain oxygen-containing copper billet.

[0121] (2) Casting: Using a semi-continuous casting method, the casting temperature is controlled at 800℃~1000℃ and held for 2 hours. After casting, an ingot is obtained.

[0122] (3) Hot rolling: The initial rolling temperature is 800℃, the final rolling temperature is not lower than 450℃, and after multiple rolling passes, a slab with a thickness of 20mm is obtained.

[0123] (4) Milling: After milling the 20.0mm slab, a 16.0mm thick slab is obtained.

[0124] (5) Rough rolling: The 16.0mm thick slab is rolled into a 1.0mm thick strip in multiple passes.

[0125] (6) Intermediate rolling: After annealing, the 1.0mm strip is rolled into a 0.4mm thick strip in two passes.

[0126] (6) Finish rolling: The 0.4mm thick strip is rolled into a copper strip with a thickness of 0.15mm after continuous annealing.

[0127] (8) Foil rolling: After intermediate annealing, the copper strip is subjected to foil rolling to further reduce the thickness of the copper foil. The foil rolling process includes the following passes:

[0128] The first pass has an entry thickness of 0.150 mm, an exit thickness of 0.097 mm, a reduction rate of 35.3%, a total entry tension of 3500 N, a total exit tension of 5500 N, a rolling force of 450 KN, and a rolling speed of 500 m / min.

[0129] The second pass has an entry thickness of 0.097 mm, an exit thickness of 0.066 mm, a reduction rate of 31.9%, a total entry tension of 3100 N, a total exit tension of 4100 N, a rolling force of 450 KN, and a rolling speed of 500 m / min.

[0130] The thickness of the third pass is 0.066 mm on the inlet side and 0.045 mm on the outlet side, with a reduction rate of 31.8%, a total inlet side tension of 2600 N, a total outlet side tension of 3200 N, a rolling force of 450 KN, and a rolling speed of 650 m / min.

[0131] The fourth pass has an entry thickness of 0.045 mm, an exit thickness of 0.032 mm, a reduction rate of 28.9%, a total entry tension of 1700 N, a total exit tension of 2100 N, a rolling force of 450 KN, and a rolling speed of 650 m / min.

[0132] The fifth pass has an entry thickness of 0.032 mm and an exit thickness of 0.023 mm, a reduction rate of 28.1%, a total entry tension of 1000 N, a total exit tension of 1200 N, a rolling force of 450 kN, and a rolling speed of 650 m / min.

[0133] The sixth pass has an inlet thickness of 0.023 mm, an outlet thickness of 0.018 mm, a reduction rate of 21.7%, a total inlet tension of 800 N, a total outlet tension of 950 N, a rolling force of 450 KN, and a rolling speed of 650 m / min, ultimately yielding a rolled copper foil with a thickness of 0.018 mm.

[0134] (9) Cooling and drying: The electroplated copper foil is cooled and then dried to obtain the final rolled copper foil product.

[0135] The folding endurance of the rolled copper foil prepared in Comparative Example 1 was tested.

[0136] The MIT flexural fatigue test was conducted using an MIT flexural fatigue testing machine. The test used a 500g weight, a bending radius R = 0.8mm, and a bending angle of 135°. The rolled copper foil product was tested and found to withstand 267 bends. It is evident that the flexural fatigue resistance of the rolled copper foil prepared in Comparative Example 1 is significantly reduced compared to the rolled copper foil product obtained in Example 1.

[0137] While this invention provides several exemplary embodiments, many other variations or modifications consistent with the principles of this invention can be directly determined or derived from the disclosure of this invention without departing from its spirit and scope. Therefore, the scope of this invention should be understood and recognized as covering all such other variations or modifications.

Claims

1. A method for preparing rolled copper foil, characterized in that, Includes the following steps: Smelting: Sn and P elements are added to the copper solution during the smelting process. After smelting, the solution contains the following components: Cu + Ag ≥ 99.85 wt%; Sn: 0.11~0.12wt% P: 0.031~0.048wt%; S≤0.0015wt%; Fe≤0.001wt%; Zn≤0.0001wt%; Bi≤0.0001wt%; Sb≤0.0004wt%; Ni≤0.001wt%; Casting: A semi-continuous casting method is used, with the casting temperature controlled at 900℃~1100℃ and held for 2 hours. After casting, an ingot is obtained. Hot-rolled; Milling; Rough rolling; Intermediate rolling; Precision rolling; Foil rolling: It consists of the following 6 rolling passes: First pass: entry thickness is 0.150mm, exit thickness is 0.097mm, reduction rate is 35.3%, total entry tension is 3500N, total exit tension is 5500N, rolling force is 450KN, rolling speed is 500m / min; Second pass: The entry thickness is 0.097mm, the exit thickness is 0.066mm, the reduction rate is 31.9%, the total entry tension is 3100N, the total exit tension is 4100N, the rolling force is 450KN, and the rolling speed is 500m / min. Third pass: The entry thickness is 0.066mm, the exit thickness is 0.045mm, the reduction rate is 31.8%, the total entry tension is 2600N, the total exit tension is 3200N, the rolling force is 450KN, and the rolling speed is 650m / min. Fourth pass: The entry thickness is 0.045mm, the exit thickness is 0.032mm, the reduction rate is 28.9%, the total entry tension is 1700N, the total exit tension is 2100N, the rolling force is 450KN, and the rolling speed is 650m / min. Fifth pass: entry thickness is 0.032mm, exit thickness is 0.023mm, reduction rate is 28.1%, total entry tension is 1000N, total exit tension is 1200N, rolling force is 450KN, rolling speed is 650m / min; The sixth pass: the thickness on the inlet side is 0.023mm, the thickness on the outlet side is 0.018mm, the reduction rate is 21.7%, the total tension on the inlet side is 800N, the total tension on the outlet side is 950N, the rolling force is 450KN, the rolling speed is 650m / min, and finally a rolled copper foil with a thickness of 0.018mm is obtained. Electroplating: The rolled copper foil obtained after foil rolling is subjected to roughening, curing and surface zinc plating treatment in sequence; Cooling and drying: The electroplated rolled copper foil is cooled and then dried to obtain the rolled copper foil product; wherein, the rolled copper foil product has a bending resistance of 639 times and a strength of 550MPa; the bending test uses a 500g weight, a bending radius R=0.8mm, and a bending angle of 135°.

2. The method for preparing rolled copper foil according to claim 1, characterized in that, In the hot rolling step: the initial rolling temperature is 850℃, the final rolling temperature is not lower than 500℃, and after multiple rolling passes, a slab with a thickness of 20mm is obtained; and / or In the milling step: the slab obtained in the hot rolling step is milled to obtain a slab with a thickness of 16.0 mm; and / or In the rough rolling step: the slab obtained in the milling step is rolled into a 1.0 mm thick strip in multiple passes; and / or In the intermediate rolling step: the strip obtained in the rough rolling step is annealed and then rolled into a 0.4 mm thick strip in two passes; and / or In the finishing rolling step: the strip obtained in the intermediate rolling step is continuously annealed and then rolled into a copper strip with a thickness of 0.15 mm.

3. The method for preparing rolled copper foil according to claim 1, characterized in that, The electroplating step includes: Roughening treatment: Cu in the roughening solution 2+ The ion concentration was 40 g / L, the H2SO4 concentration was 120 g / L, and the current density was 55 A / dm³. 2 ; Curing treatment: Cu in the curing solution 2+ The ion concentration is 50 g / L, the H2SO4 concentration is 80 g / L, and the current density is 45 A / dm³. 2 ; Surface zinc plating treatment: The concentration of ZnCl2 in the electroplating solution is 50 g / L, the concentration of KCl is 150 g / L, the concentration of boric acid is 25 g / L, the pH of the electroplating solution is 5, and the current density is 3 A / dm³. 2 .

4. A rolled copper foil prepared by the rolling copper foil preparation method according to any one of claims 1 to 3.

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