A high-peeling-resistance and high-oxidation-resistance PET composite copper foil and a preparation method thereof

Abstract

The application relates to the technical field of composite copper foil preparation, in particular to a PET composite copper foil with high peeling resistance and oxidation resistance and a preparation method thereof. The preparation method of the PET composite copper foil with high peeling resistance and oxidation resistance comprises the following steps: PET composite copper foil preparation and PET composite copper foil composite treatment. In the application, the inert structure of a PET surface is broken through corona treatment, and a polar group is introduced; then, a reinforcing liquid containing a silane coupling agent and nano silicon dioxide sol is coated to form a polar transition layer, so that the interface bonding force and the peeling resistance of the PET and the metal layer are improved through chemical bonding and physical anchoring; then, a layer of oxidation-resistant barrier metal layer is formed by using a physical vapor deposition method; then, the PET composite copper foil is placed in a copper-containing electrolyte, and electrolysis treatment is carried out by electrifying, so that a layer of copper foil is deposited, and the PET composite copper foil is obtained; and finally, the obtained PET composite copper foil is subjected to a surface treatment process.

Description

Technical Field

[0001] This invention relates to the field of composite copper foil preparation technology, specifically to a PET composite copper foil with high peel resistance and high oxidation resistance, and its preparation method. Background Technology

[0002] In the electronics industry, copper foil is a core material for signal transmission and power conduction in electronic products, and is known as the "neural network" of electronic products. Composite copper foil is an indispensable raw material for key electronic devices such as 5G high-speed communication, PCB circuit boards, and IDC servers, which directly affects the performance and stability of these electronic devices.

[0003] With the booming rise and rapid development of the global 5G industry, electronic devices are constantly moving towards high performance and miniaturization. This has placed more stringent technical requirements on copper foil for communication PCBs, specifically requiring the copper foil to be thin, lightweight, highly peel-resistant, and possess excellent oxidation resistance. However, current traditional copper foil manufacturing processes are insufficient to meet this emerging demand. Traditional copper foil is mainly produced through rolling or electrolytic processes. While rolled copper foil has a mature manufacturing process and good mechanical properties, it suffers from significant drawbacks such as complex manufacturing processes and limited foil width, making it unsuitable for the production needs of large or special-sized electronic devices. Although electrolytic processes have made some breakthroughs compared to rolling processes, enabling the production of copper foil with a thickness of less than 6μm, which has contributed to the development of industries such as new energy, the market demand for copper foil thickness has dropped to below 4μm as modern electronic devices become increasingly miniaturized. The single electrolytic process can no longer achieve this thickness breakthrough, becoming a technical bottleneck restricting the miniaturization of electronic devices.

[0004] To overcome the limitations of traditional copper foil manufacturing processes, the industry has begun exploring the application of novel substrate materials in copper foil production. PET material, with its excellent mechanical properties, insulation, and weather resistance, exhibits significant advantages as a copper foil substrate: on the one hand, during the use of electronic products, if punctured by foreign objects, the PET substrate provides excellent insulation protection, preventing damage to electronic devices due to leakage or other issues; on the other hand, when applied to PCB circuit boards, it effectively improves the copper foil's peel resistance while ensuring the integrity of the copper foil structure and reducing the risk of copper foil detachment. However, the insulation properties of PET material also bring new technical challenges to copper foil production—copper foil, as a key conductor material in integrated circuits, relies heavily on conductivity as its core performance indicator. The insulating characteristics of PET material significantly increase the difficulty of incorporating it into the copper foil production technology system. How to leverage the advantages of PET material while ensuring the conductivity of copper foil, thereby developing copper foil production technologies suitable for integrated circuits and significantly improving the application effect of copper foil in downstream electronic devices, has become a major research issue that urgently needs to be addressed in the current and future copper foil technology field.

[0005] Therefore, we propose a PET composite copper foil with high peel resistance and high oxidation resistance and its preparation method, which can meet the current requirements of the integrated circuit field for lightweight copper foil with high peel resistance. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a PET composite copper foil with high peel resistance and high oxidation resistance, and a method for preparing the same.

[0007] This invention provides a method for preparing a PET composite copper foil with high peel resistance and high oxidation resistance, comprising:

[0008] S1: Preparation of PET composite copper foil;

[0009] A reinforcing solution was prepared using silane coupling agent and nano-silica sol as raw materials. The PET film was then subjected to corona treatment. The reinforcing solution was then coated onto the corona-treated PET film. Subsequently, an antioxidant barrier metal layer and copper foil were deposited sequentially to obtain PET composite copper foil.

[0010] S2: Composite treatment of PET composite copper foil;

[0011] The obtained PET composite copper foil was subjected to roughening and alloying treatments in sequence, and then immersed in an aqueous solution containing silane coupling agent, washed with water, and dried to obtain PET composite copper foil with high peel resistance and high oxidation resistance.

[0012] As a preferred aspect, S1: The preparation of PET composite copper foil specifically includes the following steps:

[0013] S1.1: Add 4.5-5g of KH-550 and 4.5-5g of KH-560 to 100-120g of 30-40wt% ethanol aqueous solution, then add glacial acetic acid to adjust the pH to 4-5, and then stir the reaction at 300-400rpm and 35-40℃ for 4-5h. Then add 3.3-3.5g of 10-30wt% nano silica sol, stir and mix, and then stir at room temperature for 12-14h to obtain the enhanced solution.

[0014] S1.2: Add copper-containing compound, additive A, additive B, additive C, and additive D to an acidic aqueous solution with a concentration of 20-150 g / L, and stir and mix at 200-230 r / min for 20-30 min to obtain a copper-containing electrolyte.

[0015] The concentration of additive A in the copper-containing electrolyte is 2-80 mg / L, the concentration of additive B is 1-50 mg / L, the concentration of additive C is 5-100 mg / L, the concentration of additive D is 10-120 mg / L, and the concentration of copper-containing compounds, calculated as copper element, is 5-90 g / L.

[0016] S1.3: The biaxially oriented PET film is subjected to corona treatment with parameters of 10-15 m / min, power of 3-5 kW, and electrode gap of 1.5-2 mm. The reinforcing liquid is coated on the pretreated PET film and then cured at 100-110℃ for 90-120 s to obtain a PET substrate with an interface reinforcement layer.

[0017] S1.4: An antioxidant barrier metal layer is deposited on the interface strengthening layer using vacuum magnetron sputtering technology. The sputtering pressure in the vacuum chamber is 2-20 Pa, the sputtering power is 50-150 W, and the sputtering time is 30-180 s. Afterward, it is placed in a copper-containing electrolyte and allowed to stand. Electrolysis is then performed using a regulated DC power supply with a current density of 10-30 A / dm³. 2 Electrolysis time is 3-20s, electrolysis temperature is 40-60℃, and a layer of copper foil is deposited to obtain PET composite copper foil.

[0018] As a preferred aspect, S2: the lamination process of PET composite copper foil specifically includes the following steps:

[0019] S2.1: Add copper-containing compound, additive E, and rare earth sulfate to an acidic aqueous solution with a concentration of 20-150 g / L, and stir and mix at 200-230 r / min for 20-30 min to obtain a roughening solution;

[0020] The concentration of additive E in the roughening solution is 0.001-0.8 mg / L, the concentration of rare earth sulfate is 0.005-1 mg / L, and the concentration of copper-containing compounds, calculated as copper element, is 2-50 g / L.

[0021] S2.2: Add the alloying compound, complexing agent, and auxiliary metal compound to deionized water and stir at 200-230 r / min for 20-30 min to obtain the alloy liquid;

[0022] The alloy melt contains, based on alloying elements, 15-90 g / L of alloying compounds, 50-150 g / L of complexing agents, and 0.005-2 g / L of auxiliary metal compounds.

[0023] S2.3: Add the silane coupling agent to deionized water, then add a weak acid to adjust the pH of the solution to 3-6, and stir and mix at 200-230 r / min for 20-30 min to obtain an aqueous solution containing the silane coupling agent, wherein the volume fraction of the silane coupling agent is 0.5-3.5%;

[0024] S2.4: The PET composite copper foil is placed in a roughening solution and roughened using a regulated DC power supply. The current density for the roughening process is 5-30 A / dm³. 2 The time is 0.2-15s, the temperature is 20-50℃, and the roughened PET composite copper foil is alloyed in the alloy liquid using a regulated DC power supply. The current density of the alloying treatment is 1-20A / dm³. 2 The soaking time is 0.5-15s. Finally, the alloyed PET composite copper foil is immersed in an aqueous solution containing silane coupling agent for 2-120s. After soaking, it is washed with deionized water 2-4 times and then dried to obtain PET composite copper foil with high peel resistance and high oxidation resistance.

[0025] As a preferred aspect, the copper-containing compound in step S1.2 is selected from any one of copper sulfate, chloride, and nitrate; additive A is selected from any one of sodium chloride, potassium chloride, copper chloride, and lithium chloride; additive B is selected from any one of collagen, sodium polydithiopropanesulfonate, sodium 3-mercapto-1-propanesulfonate, sodium 2-mercaptoethylsulfonate, sodium 2,3-dimercaptopropanesulfonate, and sodium 3-(benzothiazol-2-mercapto)propanesulfonate; additive C is selected from any one of gelatin, fish glue, and bone glue; additive D is selected from any one of polyethylene glycol, polypropylene glycol, polyether, and hydroxyethyl cellulose; and the acidic aqueous solution is selected from any one of sulfuric acid and nitric acid.

[0026] As a preferred aspect, the antioxidant barrier metal layer in step S1.4 is any one of a gold target, a silver target, a gallium target, a tin target, a titanium target, and a nickel target.

[0027] As a preferred aspect, the copper-containing compound in step S2.1 is selected from any one of copper sulfate, chloride and nitrate; additive E is selected from any one of sodium molybdate, sodium chromate, ammonium tungstate, ferrous sulfate and stannous sulfate; rare earth sulfate is selected from any one of cerium sulfate, ytterbium sulfate, terbium sulfate, yttrium sulfate, lanthanum sulfate, europium sulfate and dysprosium sulfate; and the acidic aqueous solution is selected from any one of sulfuric acid and nitric acid.

[0028] As a preferred aspect, the alloying compound in step S2.2 is selected from at least two of zinc sulfate, cobalt sulfate, nickel sulfate, zinc chloride, cobalt chloride, nickel chloride, zinc nitrate, cobalt nitrate, nickel nitrate, hafnium oxide, zirconium sulfate, yttrium sulfate, and sodium molybdate; the complexing agent is selected from at least two of sodium citrate, potassium citrate, disodium citrate, sodium sulfite, potassium sulfite, sodium bisulfite, and potassium bisulfite; the auxiliary metal compound is selected from any one of Bi, Sn, Sb, Cd, Zn, Rb, and Cs, and the auxiliary metal compound is selected from any one of the sulfate, chloride, and nitrate salts of the auxiliary metal.

[0029] As a preferred aspect, the silane coupling agent in step S2.3 is selected from any one of γ-(methacryloyloxy)propyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-aminopropyltrimethoxysilane; the weak acid is selected from any one of oxalic acid, glacial acetic acid, citric acid, and formic acid.

[0030] The present invention also provides a PET composite copper foil with high peel resistance and high oxidation resistance, which is prepared by any of the methods described in the present invention for preparing a PET composite copper foil with high peel resistance and high oxidation resistance.

[0031] The present invention has the following advantages:

[0032] 1. In this invention, corona treatment can break the inert molecular structure of PET surface and introduce polar groups such as hydroxyl and carboxyl groups, which greatly improves the adsorption capacity of the substrate surface for subsequent coatings. At the same time, a reinforcing liquid prepared by silane coupling agent and nano silica sol is applied and cured to form a "polar transition layer": one end of the silane coupling agent is chemically bonded to the polar groups on the PET surface, and the other end forms a coordination bond with the subsequently deposited antioxidant barrier layer. The nano silica enhances the physical anchoring effect of the transition layer through particle filling. The interfacial bonding force between PET and metal layer is improved from the dual dimensions of "chemical bonding + physical anchoring", which effectively improves the peel resistance.

[0033] 2. Compared to traditional preparation methods that introduce impurities and toxic substances and have complex plating solutions, the PET composite copper foil prepared in this invention is processed under vacuum conditions to prepare the antioxidant barrier metal layer, ensuring the purity of the PET composite copper foil. This method is more efficient, simpler, and lower in cost, and produces a thinner copper foil. It can completely replace traditional copper foil in the future. Furthermore, the PET composite copper foil has high antioxidant properties, does not discolor after being placed at 220°C for 2 hours, and has good mechanical properties, meeting the current requirements for lightweight copper foil in the integrated circuit and 5G communication fields. It is flexible and has a peel strength ≥0.8N / mm, making it suitable for use in flexible circuit boards, enabling them to be lightweight, thin, and highly flexible.

[0034] 3. In this invention, silanization is one of the important post-processing steps of composite copper foil. The coated silane coupling agent plays a bonding role during the hot pressing and molding process with the resin board, which is beneficial to significantly improve the peel resistance of the copper-clad laminate. At the same time, alloying can significantly improve the oxidation resistance of the copper foil, which is of great significance for the subsequent PCB board preparation and electronic circuit etching. Due to the extremely thin thickness of PET composite copper foil, it is more easily oxidized. Silanization and alloying treatments will significantly enhance the peel resistance and oxidation resistance of the copper foil, providing an important guarantee for the stable application of copper foil in downstream products. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the structure of the PET composite copper foil of the present invention. Detailed Implementation

[0036] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of this invention.

[0037] Example 1: A method for preparing a PET composite copper foil with high peel resistance and high oxidation resistance, referring to... Figure 1 ,include:

[0038] S1: Preparation of PET Composite Copper Foil

[0039] S1.1: Add 4.5g of KH-550 and 4.5g of KH-560 to 100g of 30wt% ethanol aqueous solution, then add glacial acetic acid to adjust the pH to 4, and then stir at 300rpm and 35℃ for 4h. Then add 3.3g of 10wt% nano silica sol, stir and mix, and stir at room temperature for 12h to obtain the enhanced solution.

[0040] S1.2: Add copper sulfate pentahydrate, sodium chloride, sodium polydithiopropane sulfonate, gelatin with a glue strength of 120, and polyethylene glycol to a sulfuric acid aqueous solution with a concentration of 20 g / L, and stir and mix at 200 r / min for 20 min to obtain a copper-containing electrolyte.

[0041] The concentration of sodium chloride in the copper electrolyte is 2 mg / L, the concentration of sodium polydithiopropane sulfonate is 1 mg / L, the concentration of gelatin is 5 mg / L, the concentration of polyethylene glycol is 10 mg / L, and the concentration of copper ions is 5 g / L.

[0042] S1.3: The biaxially stretched PET film is subjected to corona treatment with parameters of 10 m / min, 3 kW power, and 1.5 mm electrode gap to achieve a surface tension of 50 dyn / cm. The strengthening liquid is then coated onto the pretreated PET film and cured at 100°C for 90 s to obtain a PET substrate with an interface strengthening layer.

[0043] S1.4: An antioxidant barrier metal layer was deposited on the interface reinforcement layer using vacuum magnetron sputtering technology. The cathode target for vacuum magnetron sputtering was a gold target. The sputtering pressure in the vacuum chamber was 2 Pa, the sputtering power was 50 W, and the sputtering time was 30 s. Afterward, the layer was placed in a copper-containing electrolyte and allowed to stand. Electrolysis was then performed using a regulated DC power supply with a current density of 10 A / dm³. 2 Electrolysis time 3s, electrolysis temperature 40℃, deposit a layer of copper foil to obtain PET composite copper foil;

[0044] S2: Composite processing of PET composite copper foil

[0045] S2.1: Add copper sulfate pentahydrate, ammonium tungstate, and terbium sulfate to a sulfuric acid aqueous solution with a concentration of 20 g / L, and stir and mix at 200 r / min for 20-30 min to obtain a roughening solution;

[0046] The concentration of ammonium tungstate in the roughening solution is 0.01 mg / L, the concentration of terbium sulfate is 0.05 mg / L, and the concentration of copper ions is 2 g / L.

[0047] S2.2: Add zinc sulfate, nickel sulfate, sodium citrate and Bi2(SO4)3 to deionized water and stir at 200 r / min for 20 min to obtain alloy solution;

[0048] In the alloy liquid, the concentration of zinc ions is 10 g / L, the concentration of nickel ions is 5 g / L, the concentration of sodium citrate is 50 g / L, and the concentration of Bi2(SO4)3, calculated as auxiliary metal, is 0.05 g / L.

[0049] S2.3: Add the silane coupling agent γ-(methacryloyloxy)propyltrimethoxysilane to deionized water, then add glacial acetic acid to adjust the pH of the solution to 3, and stir and mix at 200 r / min for 20 min to obtain an aqueous solution containing the silane coupling agent, wherein the volume fraction of the silane coupling agent is 0.5%;

[0050] S2.4: The PET composite copper foil is placed in a roughening solution and roughened using a regulated DC power supply. The current density for the roughening process is 5 A / dm³. 2 The roughened PET composite copper foil was alloyed in a molten alloy solution at a time of 0.2 s and a temperature of 20 °C using a regulated DC power supply. The current density for alloying was 1 A / dm³. 2 The time was 0.5s. Finally, the alloyed PET composite copper foil was immersed in an aqueous solution containing silane coupling agent for 2s. After immersion, it was washed twice with deionized water and then dried to obtain PET composite copper foil with high peel resistance and high oxidation resistance.

[0051] Example 2: A method for preparing a PET composite copper foil with high peel resistance and high oxidation resistance, see [link to example]. Figure 1 ,include:

[0052] S1: Preparation of PET Composite Copper Foil

[0053] S1.1: Add 4.75g of KH-550 and 4.75g of KH-560 to 110g of 35wt% ethanol aqueous solution, then add glacial acetic acid to adjust the pH to 4.5, and then stir at 350rpm and 37.5℃ for 4.5h. Then add 3.4g of 20wt% nano silica sol, stir and mix, and stir at room temperature for 13h to obtain the enhanced solution.

[0054] S1.2: Add copper nitrate pentahydrate, copper chloride, sodium 3-mercapto-1-propanesulfonate, fish glue, and polyether to an 85 g / L nitric acid aqueous solution and stir at 215 r / min for 25 min to obtain a copper-containing electrolyte.

[0055] The concentration of copper chloride in the copper-containing electrolyte was 41 mg / L, the concentration of sodium 3-mercapto-1-propanesulfonate was 25.5 mg / L, the concentration of fish glue was 52.5 mg / L, the concentration of polyether was 65 mg / L, and the concentration of copper ions was 47.5 g / L.

[0056] S1.3: The biaxially oriented PET film is subjected to corona treatment with parameters of 12.5 m / min, 4 kW power, and 1.75 mm electrode gap to achieve a surface tension of 52.5 dyn / cm. The strengthening liquid is then applied to the pretreated PET film and cured at 105 °C for 105 s to obtain a PET substrate with an interface strengthening layer.

[0057] S1.4: An antioxidant barrier metal layer was deposited on the interface reinforcement layer using vacuum magnetron sputtering technology. The cathode target for vacuum magnetron sputtering was a silver target. The sputtering pressure in the vacuum chamber was 11 Pa, the sputtering power was 100 W, and the sputtering time was 105 s. Afterward, the layer was placed in a copper-containing electrolyte and allowed to stand. Electrolysis was then performed using a regulated DC power supply with a current density of 20 A / dm³. 2 Electrolysis time 11.5s, electrolysis temperature 50℃, deposit a layer of copper foil to obtain PET composite copper foil;

[0058] S2: Composite processing of PET composite copper foil

[0059] S2.1: Add copper nitrate pentahydrate, sodium chromate, and ytterbium sulfate to an aqueous nitric acid solution with a concentration of 85 g / L, and stir and mix at 215 r / min for 25 min to obtain a roughening solution;

[0060] The concentration of sodium chromate in the roughening solution was 0.4 mg / L, the concentration of ytterbium sulfate was 0.5 mg / L, and the concentration of copper ions was 26 g / L.

[0061] S2.2: Add nickel nitrate, cobalt nitrate, disodium citrate and Sb2(SO4)3 to deionized water and stir at 215 r / min for 25 min to obtain alloy liquid;

[0062] In the alloy liquid, the concentration of nickel ions is 18 g / L, the concentration of cobalt ions is 32.5 g / L, the concentration of disodium citrate is 100 g / L, and the concentration of Sb2(SO4)3, calculated as auxiliary metal, is 1 g / L.

[0063] S2.3: Add the silane coupling agent γ-aminopropyltrimethoxysilane to deionized water, then add oxalic acid to adjust the pH of the solution to 4.5, and stir and mix at 215 r / min for 25 min to obtain an aqueous solution containing the silane coupling agent, wherein the volume fraction of the silane coupling agent is 2%;

[0064] S2.4: The PET composite copper foil is placed in a roughening solution and roughened using a regulated DC power supply. The current density for the roughening process is 17.5 A / dm³. 2 The process involved alloying the roughened PET composite copper foil in a molten alloy solution at a time of 7.6 seconds and a temperature of 35°C using a regulated DC power supply. The current density for alloying was 10 A / dm³. 2 The time was 7.5s. Finally, the alloyed PET composite copper foil was immersed in an aqueous solution containing silane coupling agent for 60s. After immersion, it was washed three times with deionized water and then dried to obtain PET composite copper foil with high peel resistance and high oxidation resistance.

[0065] Example 3: A method for preparing a PET composite copper foil with high peel resistance and high oxidation resistance, see [link to example]. Figure 1 ,include:

[0066] S1: Preparation of PET Composite Copper Foil

[0067] S1.1: Add 5g of KH-550 and 5g of KH-560 to 120g of 40wt% ethanol aqueous solution, then add glacial acetic acid to adjust the pH to 5, then stir at 400rpm and 40℃ for 5h, then add 3.5g of 30wt% nano silica sol, stir and mix, and stir at room temperature for 14h to obtain the enhanced solution;

[0068] S1.2: Add copper sulfate pentahydrate, lithium chloride, sodium 2-mercaptoethyl sulfonate, bone glue, and hydroxyethyl cellulose to a sulfuric acid aqueous solution with a concentration of 150 g / L, and stir and mix at 230 r / min for 30 min to obtain a copper-containing electrolyte.

[0069] The concentration of lithium chloride in the copper electrolyte is 80 mg / L, the concentration of sodium 2-mercaptoethyl sulfonate is 50 mg / L, the concentration of bone glue is 100 mg / L, the concentration of hydroxyethyl cellulose is 120 mg / L, and the concentration of copper ions is 90 g / L.

[0070] S1.3: The biaxially stretched PET film is subjected to corona treatment with parameters of 15 m / min, 5 kW power, and 2 mm electrode gap to achieve a surface tension of 55 dyn / cm. The strengthening liquid is then coated onto the pretreated PET film and cured at 110℃ for 120 s to obtain a PET substrate with an interface strengthening layer.

[0071] S1.4: An antioxidant barrier metal layer was deposited on the interface strengthening layer using vacuum magnetron sputtering technology. The cathode target for vacuum magnetron sputtering was a copper target. The sputtering pressure in the vacuum chamber was 20 Pa, the sputtering power was 150 W, and the sputtering time was 180 s. Afterward, the target was placed in a copper-containing electrolyte and subjected to electrolysis using a regulated DC power supply. The electrolysis parameters were a current density of 30 A / dm³. 2 Electrolysis time 20s, electrolysis temperature 60℃, deposit a layer of copper foil to obtain PET composite copper foil;

[0072] S2: Composite processing of PET composite copper foil

[0073] S2.1: Add copper sulfate pentahydrate, sodium molybdate, and yttrium sulfate to a sulfuric acid aqueous solution with a concentration of 150 g / L, and stir and mix at 230 r / min for 30 min to obtain a roughening solution;

[0074] The concentration of sodium molybdate in the roughening solution is 0.8 mg / L, the concentration of yttrium sulfate is 1 mg / L, and the concentration of copper ions is 50 g / L.

[0075] S2.2: Cobalt sulfate, zinc chloride, potassium sulfite, and CdCl2 are added to deionized water and stirred at 230 r / min for 30 min to obtain an alloy solution;

[0076] In the alloy liquid, the concentration of cobalt ions is 30 g / L, the concentration of zinc ions is 40 g / L, the concentration of potassium sulfite is 150 g / L, and the concentration of CdCl2, calculated as auxiliary metal, is 2 g / L.

[0077] S2.3: Add the silane coupling agent γ-glycidoxypropyltrimethoxysilane to deionized water, then add formic acid to adjust the pH of the solution to 6, and stir and mix at 230 r / min for 30 min to obtain an aqueous solution containing the silane coupling agent, wherein the volume fraction of the silane coupling agent is 3.5%;

[0078] S2.4: The PET composite copper foil is placed in a roughening solution and roughened using a regulated DC power supply. The current density for the roughening process is 30 A / dm³. 2 The roughened PET composite copper foil was alloyed in a molten alloy solution at a time of 15 seconds and a temperature of 50°C using a regulated DC power supply. The current density for the alloying process was 20 A / dm³. 2 The time was 15s. Finally, the alloyed PET composite copper foil was immersed in an aqueous solution containing silane coupling agent for 120s. After immersion, it was washed 4 times with deionized water and then dried to obtain PET composite copper foil with high peel resistance and high oxidation resistance.

[0079] Comparative Example 1 differs from Example 1 in that steps S1.1 and S1.3 are removed, and step S1.4 involves depositing an antioxidant barrier metal layer on the surface of a PET substrate using vacuum magnetron sputtering technology. The remaining steps are unchanged to prepare PET composite copper foil. This is referred to as Comparative Example 1.

[0080] Comparative Example 2 differs from Example 1 in that Comparative Example 2 involves soaking in an aqueous solution containing silane coupling agent in steps S2.3 and S2.4, while the remaining steps remain unchanged to prepare PET composite copper foil. This is referred to as Comparative Example 2.

[0081] The peel strength of the copper foil layer of the PET composite copper foil prepared in Examples 1-3 and Comparative Examples 1-2 was measured, and the results are shown in Table 1. The peel strength was measured using a peel strength tester.

[0082] Table 1. Results of peel strength test in Examples 1-3 and Comparative Examples 1-2

[0083] Peel strength (N / mm) Example 1 0.83 Example 2 0.88 Example 3 0.92 Comparative Example 1 0.45 Comparative Example 2 0.63

[0084] As can be seen from the data in Table 1, the PET composite copper foil prepared by this invention has high peel strength. The data from Comparative Example 1 shows that coating with a reinforcing solution prepared from silane coupling agent and nano-silica sol can effectively improve peel strength; the data from Comparative Example 2 shows that immersing the alloyed copper foil in an aqueous solution containing silane coupling agent can further improve its peel performance.

[0085] The properties of the PET composite copper foils prepared in Examples 1-3 were measured, and the results are shown in Table 2.

[0086] Tensile strength and elongation were measured using a tensile testing machine.

[0087] Table 2. Performance test results of PET composite copper foil in Examples 1-3

[0088] Tensile strength (MPa) Elongation (%) Example 1 324 5.4 Example 2 331 5.9 Example 3 333 6.1

[0089] The data in Table 2 show that PET composite copper foil has good mechanical properties, which meets the current requirements of integrated circuits for lightweight copper foil.

[0090] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims. Parts not described in detail in this specification are prior art known to those skilled in the art.

Claims

1. A method for preparing a PET composite copper foil with high peel resistance and high oxidation resistance, characterized in that, include: S1: Preparation of PET composite copper foil; Add 4.5-5g of KH-550 and 4.5-5g of KH-560 to 100-120g of 30-40wt% ethanol aqueous solution, then add glacial acetic acid to adjust the pH to 4-5, and then stir the reaction at 300-400rpm and 35-40℃ for 4-5h. Then add 3.3-3.5g of 10-30wt% nano silica sol, stir and mix, and stir at room temperature for 12-14h to obtain a strengthening solution. Perform corona treatment on the PET film, then coat the strengthening solution onto the corona-treated PET film, and then deposit an antioxidant barrier metal layer and copper foil in sequence to obtain PET composite copper foil. The antioxidant barrier metal layer is any one of gold, silver, gallium, tin, titanium, and nickel; S2: Composite treatment of PET composite copper foil; The PET composite copper foil was placed in a roughening solution and roughened using a regulated DC power supply. The current density of the roughening process was 5-30 A / dm³. 2 The time is 0.2-15s, the temperature is 20-50℃, and the roughened PET composite copper foil is alloyed in the alloy liquid using a regulated DC power supply. The current density of the alloying treatment is 1-20A / dm³. 2 The soaking time is 0.5-15s. Finally, the alloyed PET composite copper foil is immersed in an aqueous solution containing silane coupling agent for 2-120s. After soaking, it is washed with deionized water 2-4 times and then dried to obtain PET composite copper foil with high peel resistance and high oxidation resistance.

2. The method for preparing a PET composite copper foil with high peel resistance and high oxidation resistance according to claim 1, characterized in that, S1: The preparation of PET composite copper foil includes the following steps: S1.1: Preparation of the strengthening solution; S1.2: Add copper-containing compound, additive A, additive B, additive C, and additive D to an acidic aqueous solution with a concentration of 20-150 g / L, and stir and mix at 200-230 r / min for 20-30 min to obtain a copper-containing electrolyte. Among them, additive A is selected from any one of sodium chloride, potassium chloride, copper chloride, and lithium chloride; additive B is selected from any one of collagen, sodium polydithiopropane sulfonate, sodium 3-mercapto-1-propane sulfonate, sodium 2-mercaptoethyl sulfonate, sodium 2,3-dimercaptopropane sulfonate, and sodium 3-(benzothiazol-2-mercapto)propane sulfonate; additive C is selected from any one of gelatin, fish glue, and bone glue; additive D is selected from any one of polyethylene glycol, polypropylene glycol, polyether, and hydroxyethyl cellulose; and the acidic aqueous solution is selected from any one of sulfuric acid and nitric acid. The concentration of additive A in the copper-containing electrolyte is 2-80 mg / L, the concentration of additive B is 1-50 mg / L, the concentration of additive C is 5-100 mg / L, the concentration of additive D is 10-120 mg / L, and the concentration of copper-containing compounds, calculated as copper element, is 5-90 g / L. S1.3: The biaxially oriented PET film is subjected to corona treatment with parameters of 10-15 m / min, power of 3-5 kW, and electrode gap of 1.5-2 mm. The reinforcing liquid is coated on the pretreated PET film and then cured at 100-110℃ for 90-120 s to obtain a PET substrate with an interface reinforcement layer. S1.4: An antioxidant barrier metal layer is deposited on the interface strengthening layer using vacuum magnetron sputtering technology. The sputtering pressure in the vacuum chamber is 2-20 Pa, the sputtering power is 50-150 W, and the sputtering time is 30-180 s. Afterward, it is placed in a copper-containing electrolyte and allowed to stand. Electrolysis is then performed using a regulated DC power supply with a current density of 10-30 A / dm³. 2 Electrolysis time is 3-20s, electrolysis temperature is 40-60℃, and a layer of copper foil is deposited to obtain PET composite copper foil.

3. The method for preparing a PET composite copper foil with high peel resistance and high oxidation resistance according to claim 1, characterized in that, S2: the composite treatment of the PET composite copper foil specifically includes the following steps: S2.1: Add copper-containing compound, additive E, and rare earth sulfate to an acidic aqueous solution with a concentration of 20-150 g / L, and stir and mix at 200-230 r / min for 20-30 min to obtain a roughening solution; in, Additive E is selected from any one of sodium molybdate, sodium chromate, ammonium tungstate, ferrous sulfate, and stannous sulfate; The concentration of additive E in the roughening solution is 0.001-0.8 mg / L, the concentration of rare earth sulfate is 0.005-1 mg / L, and the concentration of copper-containing compounds, calculated as copper element, is 2-50 g / L. S2.2: Add the alloying compound, complexing agent, and auxiliary metal compound to deionized water and stir at 200-230 r / min for 20-30 min to obtain the alloy liquid; The alloying compound is selected from at least two of zinc sulfate, cobalt sulfate, nickel sulfate, zinc chloride, cobalt chloride, nickel chloride, zinc nitrate, cobalt nitrate, nickel nitrate, hafnium oxide, zirconium sulfate, yttrium sulfate, and sodium molybdate; the complexing agent is selected from at least two of sodium citrate, potassium citrate, disodium citrate, sodium sulfite, potassium sulfite, sodium bisulfite, and potassium bisulfite; the auxiliary metal compound is selected from any one of Bi, Sn, Sb, Cd, Rb, and Cs, and the auxiliary metal compound is selected from any one of the sulfate, chloride, and nitrate salts of the auxiliary metal. The alloy melt contains, based on alloying elements, 15-90 g / L of alloying compounds, 50-150 g / L of complexing agents, and 0.005-2 g / L of auxiliary metal compounds. S2.3: Add the silane coupling agent to deionized water, then add a weak acid to adjust the pH of the solution to 3-6, and stir and mix at 200-230 r / min for 20-30 min to obtain an aqueous solution containing the silane coupling agent, wherein the volume fraction of the silane coupling agent is 0.5-3.5%; S2.4: The PET composite copper foil is roughened and alloyed. Finally, the alloyed PET composite copper foil is immersed in an aqueous solution containing silane coupling agent and then dried to obtain a PET composite copper foil with high peel resistance and high oxidation resistance.

4. The method for preparing a PET composite copper foil with high peel resistance and high oxidation resistance according to claim 2, characterized in that, The copper-containing compound in step S1.2 is selected from any one of copper sulfate, chloride and nitrate.

5. The method for preparing a PET composite copper foil with high peel resistance and high oxidation resistance according to claim 3, characterized in that, The copper-containing compound in step S2.1 is selected from any one of copper sulfate, chloride and nitrate; the rare earth sulfate is selected from any one of cerium sulfate, ytterbium sulfate, terbium sulfate, yttrium sulfate, lanthanum sulfate, europium sulfate and dysprosium sulfate; the acidic aqueous solution is selected from any one of sulfuric acid and nitric acid.

6. The method for preparing a PET composite copper foil with high peel resistance and high oxidation resistance according to claim 3, characterized in that, The silane coupling agent in step S2.3 is selected from any one of γ-(methacryloyloxy)propyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-aminopropyltrimethoxysilane; the weak acid is selected from any one of oxalic acid, glacial acetic acid, citric acid, and formic acid.

7. A PET composite copper foil with high peel resistance and high oxidation resistance, characterized in that, It is prepared by the method for preparing a PET composite copper foil with high peel resistance and high oxidation resistance as described in any one of claims 1-6.

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