A method for electroless copper plating on the surface of a polymer film

Abstract

The application provides a method for electroless copper plating on the surface of a polymer film, which comprises the following steps: (1) performing plasma surface modification treatment on the polymer film; (2) sequentially performing activation treatment and activation reduction treatment on the polymer film after the plasma surface modification treatment in step (1); and (3) performing electroless copper plating on the polymer film after the activation reduction treatment in step (2) to obtain a copper-plated polymer film. The method effectively avoids the problem of poor adhesion between the copper plating layer and the polymer film by sequentially performing plasma surface modification treatment, activation treatment and activation reduction treatment on the polymer film, ensures uniform plating layer and good adhesion between the plating layer and the polymer film, is conducive to copper deposition, avoids the phenomenon of missed plating, and makes the adhesion between the electroless copper plating layer and the polymer film greater than 10 N / cm.

Description

Technical Field

[0001] This invention belongs to the field of polymer thin film processing technology, and particularly relates to a method for chemically plating copper on the surface of a polymer thin film. Background Technology

[0002] Lithium-ion batteries (LiB) have wide applications in both electronic devices and the automotive industry. However, with the increasing miniaturization of electronic devices and the lightweighting of automobiles, there is a need to further improve the energy density of LiB.

[0003] Traditional copper foil suffers from significant disadvantages in performance, safety, and lifespan due to its heavy basis weight and low flexibility. Recent studies have highlighted composite copper materials as a viable alternative. Composite copper materials weigh only half as much as traditional copper foil, making them lighter. Polymer materials such as polypropylene (PP) and polyethylene terephthalate (PET) are inherently flexible, allowing composite copper materials to be bent and rolled, thus improving lithium battery safety. Furthermore, composite copper materials are significantly cheaper, greatly reducing the production cost of lithium batteries. However, one key technical challenge lies in the lack of active functional groups in polymer materials, their strong hydrophobicity, and the difficulty in forming a well-bonded metallic coating on their surface, limiting their industrial applications.

[0004] Currently, the existing technologies for preparing composite copper materials using polymer thin films mainly include the following three methods: First, a one-step wet or dry method is used, where the surface roughness of the polymer thin film is first improved, and then a metallic copper layer is deposited on the surface of the polymer thin film by chemical deposition, or by using magnetron sputtering or developing an integrated magnetron sputtering and vacuum evaporation machine for copper plating; Second, a two-step method of magnetron sputtering + aqueous electroplating is used, where after the basic copper film is formed by magnetron sputtering, the copper layers on both sides are thickened to about 1μm by aqueous electroplating to achieve conductivity; Third, a three-step method of magnetron sputtering + vacuum evaporation + aqueous electroplating is used, where a vacuum evaporation step is added after magnetron sputtering to quickly supplement the copper film to a thickness suitable for electroplating.

[0005] The aforementioned methods require stringent preparation conditions and are costly. Furthermore, the adhesion of the coating still needs improvement, and the primary material processed is PET. Metallization of PP is more challenging than that of polymers like PET and BOPP. Therefore, there is an urgent need to develop a method that can improve coating adhesion while being simple and easy to operate to meet application requirements. Summary of the Invention

[0006] The purpose of this invention is to provide a method for electroless copper plating on the surface of a polymer film. After the polymer film is subjected to plasma surface modification, activation and activation reduction treatment, the adhesion between the electroless copper plating layer and the polymer film is improved, ensuring that the electroless copper plating layer is uniformly attached to the surface of the polymer film, with almost no leakage points, thus avoiding the leakage point defects caused by traditional magnetron sputtering.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] This invention provides a method for chemically plating copper on the surface of a polymer film, the method comprising the following steps:

[0009] (1) The polymer film is subjected to plasma surface modification treatment;

[0010] (2) The polymer film after the plasma surface modification treatment in step (1) is subjected to activation treatment and activation reduction treatment in sequence;

[0011] (3) The polymer film after activation and reduction treatment in step (2) is chemically plated with copper to obtain a copper-plated polymer film.

[0012] In this invention, the copper-plated polymer film obtained by the method has a polymer film as the middle layer and copper conductive layers as the upper and lower layers, forming a structure similar to a "sandwich".

[0013] The method described in this invention, by sequentially performing plasma surface modification, activation, and activation-reduction treatments on the polymer film, effectively avoids the problem of poor adhesion between the copper plating layer and the polymer film, ensuring uniform plating and good adhesion between the plating layer and the polymer film, which is beneficial for copper deposition and avoids incomplete plating.

[0014] It is worth noting that by performing plasma surface modification on the polymer film, an appropriate amount of polar functional groups are introduced, which promotes the subsequent activation process. At the same time, the plasma surface modification process causes little damage to the interior of the polymer film substrate, does not affect the mechanical properties of the polymer film, and does not significantly increase the roughness.

[0015] As a preferred technical solution of the present invention, the polymer film in step (1) is made of polypropylene.

[0016] It is worth noting that PP material lacks active functional groups, has strong hydrophobicity, and it is difficult to form a metal coating with excellent adhesion on its surface, which limits its application in the industrial field. Therefore, PP material needs to be modified.

[0017] Preferably, the thickness of the polymer film in step (1) is 1-10 μm, for example, it can be 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm or 10 μm, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0018] Preferably, the surface roughness of the polymer film in step (1) is <0.09μm, for example, it can be 0.03μm, 0.04μm, 0.05μm, 0.06μm, 0.07μm or 0.08μm, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0019] As a preferred technical solution of the present invention, the plasma surface modification treatment in step (1) includes: pretreatment, surface modification and cleaning of the polymer film by plasma treatment in sequence.

[0020] It is worth noting that the present invention modifies the surface of polymer films through specific procedures of pretreatment, surface modification and cleaning. While introducing polar functional groups, the mechanical properties of the polymer films are not affected and the roughness is not significantly increased.

[0021] Preferably, after the plasma surface modification treatment described in step (1), the surface roughness of the polymer film is <0.1μm, for example, it can be 0.04μm, 0.05μm, 0.06μm, 0.07μm, 0.08μm or 0.09μm, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0022] It is worth noting that by controlling the range of plasma parameters in plasma surface modification treatment, this invention introduces polar functional groups without affecting the mechanical properties of the polymer film, and without significantly increasing its roughness.

[0023] Preferably, the pressure of the plasma treatment is 100-300 mTorr, for example, it can be 120 mTorr, 150 mTorr, 170 mTorr, 200 mTorr, 220 mTorr, 250 mTorr or 270 mTorr, etc., but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0024] Preferably, the power of the plasma treatment is 3-7kW, for example, it can be 3.5kW, 4kW, 4.5kW, 5kW, 5.5kW, 6kW or 6.5kW, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0025] Preferably, the total gas flow rate of the plasma treatment is 1.5-3.5 L / min, for example, it can be 1.7 L / min, 1.9 L / min, 2 L / min, 2.5 L / min, 3 L / min or 3.2 L / min, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0026] Preferably, the surface modification temperature is higher than the pretreatment temperature.

[0027] The present invention controls the surface modification temperature to be higher than the pretreatment temperature, which is beneficial to the formation of surface-active functional groups.

[0028] As a preferred technical solution of the present invention, the gases in the pretreatment include, by volume percentage: 60-90 v / v% oxygen, 0-40 v / v% nitrogen, 0-40 v / v% argon and 0-40 v / v% helium.

[0029] In this invention, the total percentage of various gases in the pretreatment is 100v / v%.

[0030] In this invention, the proportion of oxygen in the pretreatment is 60-90 v / v%, for example, it can be 65 v / v%, 70 v / v%, 75 v / v%, 80 v / v%, or 85 v / v%, etc.; the proportion of nitrogen in the pretreatment is 0-40 v / v%, for example, it can be 5 v / v%, 10 v / v%, 15 v / v%, 20 v / v%, 25 v / v%, 30 v / v%, or 35 v / v%, etc.; and the proportion of argon in the pretreatment is 0-40 v / v%. For example, it can be 5v / v%, 10v / v%, 15v / v%, 20v / v%, 25v / v%, 30v / v%, or 35v / v%, etc. The proportion of helium in the pretreatment is 0-40v / v%, for example, it can be 5v / v%, 10v / v%, 15v / v%, 20v / v%, 25v / v%, 30v / v%, or 35v / v%, etc., but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0031] Preferably, the pretreatment temperature is 30-60℃, for example, it can be 32℃, 35℃, 37℃, 40℃, 45℃, 50℃, 55℃ or 57℃, etc., but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0032] Preferably, the pretreatment time is 2-5 min, for example, it can be 2.2 min, 2.5 min, 2.8 min, 3 min, 3.2 min, 3.5 min, 3.8 min, 4 min, 4.2 min, 4.5 min or 4.8 min, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0033] As a preferred technical solution of the present invention, the gases in the surface modification include, by volume percentage: 50-80 v / v% oxygen, 0-20 v / v% nitrogen and 10-30 v / v% ammonia.

[0034] In this invention, the total percentage of various gases in the surface modification is 100v / v%.

[0035] In this invention, the proportion of oxygen in the surface modification is 50-80 v / v%, for example, it can be 55 v / v%, 60 v / v%, 65 v / v%, 70 v / v%, or 75 v / v%, etc.; the proportion of nitrogen in the surface modification is 0-20 v / v%, for example, it can be 5 v / v%, 10 v / v%, 15 v / v%, or 17 v / v%, etc.; and the proportion of ammonia in the surface modification is 10-30 v / v%, for example, it can be 12 v / v%, 15 v / v%, 17 v / v%, 19 v / v%, 20 v / v%, 22 v / v%, 25 v / v%, or 27 v / v%, etc., but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0036] Preferably, the volume ratio of oxygen to ammonia in the surface modification is (2-6):1, for example, it can be 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1 or 5.5:1, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0037] It is worth noting that, within the range of oxygen to ammonia volume ratio, the oxygen to ammonia volume ratio still needs to be further controlled to (2-6):1. This is beneficial for modifying the surface of the polymer film, introducing appropriate amounts of polar functional groups such as -NH2, -OH, and -COOH, promoting the adsorption of subsequent ionic palladium activator, and improving the bonding force between the subsequent copper plating layer and the polymer film.

[0038] Preferably, the surface modification temperature is 50-99℃, for example, it can be 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃ or 95℃, etc., but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0039] Preferably, the surface modification time is 2-10 min, for example, it can be 3 min, 4 min, 5 min, 6 min, 7 min, 8 min or 9 min, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0040] As a preferred technical solution of the present invention, the cleaning gases include, by volume percentage: 60-90 v / v% oxygen, 0-40 v / v% nitrogen, 0-40 v / v% argon and 0-40 v / v% helium.

[0041] In this invention, the total percentage of various gases in the cleaning process is 100v / v%.

[0042] In this invention, the oxygen content in the cleaning process is 60-90 v / v%, for example, it can be 65 v / v%, 70 v / v%, 75 v / v%, 80 v / v%, or 85 v / v%, etc.; the nitrogen content in the cleaning process is 0-40 v / v%, for example, it can be 5 v / v%, 10 v / v%, 15 v / v%, 20 v / v%, 25 v / v%, 30 v / v%, or 35 v / v%, etc.; and the argon content in the cleaning process is 0-40 v / v%. For example, it can be 5v / v%, 10v / v%, 15v / v%, 20v / v%, 25v / v%, 30v / v%, or 35v / v%, etc., and the proportion of helium in the cleaning process is 0-40v / v%, for example, it can be 5v / v%, 10v / v%, 15v / v%, 20v / v%, 25v / v%, 30v / v%, or 35v / v%, etc., but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0043] Preferably, the cleaning temperature is 30-99℃, for example, it can be 35℃, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃ or 85℃, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0044] Preferably, the cleaning time is 2-5 minutes, for example, it can be 2.2 minutes, 2.5 minutes, 2.8 minutes, 3 minutes, 3.2 minutes, 3.5 minutes, 3.8 minutes, 4 minutes, 4.2 minutes, 4.5 minutes or 4.8 minutes, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0045] As a preferred technical solution of the present invention, the activation treatment in step (2) includes: immersing the polymer film after plasma surface modification treatment in an activation solution for activation treatment.

[0046] In this invention, after the polymer film undergoes plasma surface modification treatment, it needs to be activated as soon as possible. The interval between the two treatments should be controlled within 4 hours to avoid a sharp reduction in the number of polar functional groups, which would prevent the adsorption of sufficient activator.

[0047] Preferably, the activating solution comprises a solution containing palladium ions.

[0048] Preferably, the concentration of palladium ions in the activation solution is 3-20 mg / L, for example, it can be 5 mg / L, 7 mg / L, 9 mg / L, 10 mg / L, 12 mg / L, 15 mg / L, 17 mg / L or 19 mg / L, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0049] It is worth noting that the present invention controls the concentration of palladium ions in the activation solution within a specific range to ensure that the corresponding effect is achieved. If the concentration of palladium ions is too low, the activation effect will be poor; if the concentration of palladium ions is too high, it will lead to a waste of costs.

[0050] Preferably, the activation temperature in step (2) is 45-55℃, for example, it can be 46℃, 47℃, 48℃, 49℃, 50℃, 51℃, 52℃, 53℃ or 54℃, etc., but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0051] Preferably, the activation treatment time in step (2) is 0.5-5 min, for example, it can be 0.7 min, 1 min, 2.2 min, 2.5 min, 2.8 min, 3 min, 3.2 min, 3.5 min, 3.8 min, 4 min, 4.2 min, 4.5 min or 4.8 min, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0052] Preferably, the activation and reduction treatment in step (2) includes: immersing the activated polymer film in a reduction solution for activation and reduction treatment.

[0053] The reducing solution described in this invention uses conventional reducing solutions from the prior art, and those skilled in the art can select one according to actual needs.

[0054] Preferably, the activation and reduction treatment temperature in step (2) is 30-40℃, for example, it can be 31℃, 32℃, 33℃, 34℃, 35℃, 36℃, 37℃, 38℃ or 39℃, etc., but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0055] Preferably, the activation and reduction treatment time in step (2) is 0.5-3 min, for example, it can be 0.7 min, 1 min, 1.2 min, 1.5 min, 1.7 min, 1.9 min, 2 min, 2.2 min, 2.5 min, 2.7 min or 2.9 min, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0056] As a preferred technical solution of the present invention, the chemical copper plating in step (3) includes: immersing the activated and reduced polymer film in a copper plating solution for chemical copper plating, thereby forming a chemical copper plating layer on both sides of the polymer film.

[0057] Preferably, the stress of the electroless copper plating solution is -100MPa to 100MPa, for example, it can be ±90MPa, ±80MPa, ±70MPa, ±60MPa, ±50MPa, ±40MPa, ±30MPa, ±20MPa, ±10MPa or 0MPa, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0058] In this invention, a positive stress value represents tensile stress, and a negative stress value represents compressive stress.

[0059] In this invention, as long as the stress of the electroless copper plating solution is within ±100MPa, its specific components are not specifically limited, and those skilled in the art can select them according to actual needs.

[0060] Preferably, the thickness of the electroless copper plating layer is 0.1-1.2 μm, for example, it can be 0.2 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.8 μm, 1.0 μm or 1.1 μm, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0061] It is worth noting that the electroless copper plating solution described in this invention has low stress, and the bonding force between the formed electroless copper plating layer and the polymer film is >10N / cm.

[0062] Preferably, the temperature of the electroless copper plating in step (3) is 25-40℃, for example, it can be 27℃, 29℃, 31℃, 32℃, 33℃, 34℃, 36℃, 38℃ or 40℃, etc., but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0063] Preferably, the time for electroless copper plating in step (3) is 2-10 min, for example, it can be 3 min, 4.5 min, 5 min, 5.5 min, 6 min, 6.5 min, 7 min, 7.5 min, 8 min, 9 min or 10 min, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0064] As a preferred technical solution of the present invention, step (3) further includes sequential water washing and drying after the chemical copper plating.

[0065] Preferably, the drying temperature is 100-120℃, for example, it can be 102℃, 105℃, 107℃, 109℃, 110℃, 112℃, 115℃, 117℃ or 119℃, etc., but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0066] Preferably, the drying time is 2-10 min, for example, it can be 2.5 min, 3 min, 4 min, 5.5 min, 6 min, 6.5 min, 7 min, 7.5 min, 8 min, 8.5 min, 9 min or 9.5 min, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0067] As a preferred technical solution of the present invention, the method includes the following steps:

[0068] (1) Plasma surface modification treatment was performed on polymer films with a thickness of 1-10 μm and a surface roughness of <0.09 μm;

[0069] The polymer film is made of polypropylene;

[0070] The plasma surface modification treatment includes: pretreatment, surface modification, and cleaning of the polymer film using plasma treatment in sequence; the surface modification temperature is higher than the pretreatment temperature;

[0071] After the plasma surface modification treatment, the surface roughness of the polymer film is <0.1μm;

[0072] The plasma treatment is performed at a pressure of 100-300 mTorr, a power of 3-7 kW, and a total gas flow rate of 1.5-3.5 L / min.

[0073] The gases used in the pretreatment, by volume percentage, include: 60-90 v / v% oxygen, 0-40 v / v% nitrogen, 0-40 v / v% argon, and 0-40 v / v% helium; the pretreatment temperature is 30-60℃ and the time is 2-5 min.

[0074] The gases used in the surface modification process, by volume percentage, include: 50-80 v / v% oxygen, 0-20 v / v% nitrogen, and 10-30 v / v% ammonia; the surface modification temperature is 50-99℃ and the time is 2-10 min.

[0075] The cleaning process involves gases comprising, by volume percentage: 60-90 v / v% oxygen, 0-40 v / v% nitrogen, 0-40 v / v% argon, and 0-40 v / v% helium; the cleaning temperature is 30-99°C, and the cleaning time is 2-5 minutes.

[0076] (2) Immerse the polymer film after plasma surface modification treatment in step (1) in the activation solution and activate it at 45-55℃ for 0.5-5 min, and then immerse it in the reduction solution and activate and reduce it at 30-40℃ for 0.5-3 min.

[0077] The activation solution includes a solution containing palladium ions; the concentration of palladium ions in the activation solution is 3-20 mg / L;

[0078] (3) Immerse the polymer film after activation and reduction treatment in step (2) in a chemical copper plating solution with stress of -100MPa to 100MPa, and perform chemical copper plating at 25-40℃ for 2-10 minutes to form a chemical copper plating layer with a thickness of 0.1-1.2μm on both sides of the polymer film. Then, wash with water and dry in sequence to obtain a copper-plated polymer film.

[0079] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0080] Compared with the prior art, the present invention has the following beneficial effects:

[0081] (1) The present invention introduces an appropriate amount of polar functional groups by performing plasma surface modification on polymer films, which promotes the subsequent activation process. At the same time, the plasma surface modification process causes little damage to the interior of the polymer film substrate, does not affect the mechanical properties of the polymer film, and does not significantly increase the roughness.

[0082] (2) The method provided by the present invention effectively avoids the problem of poor bonding force between the copper plating layer and the polymer film by sequentially performing plasma surface modification treatment, activation treatment and activation reduction treatment on the polymer film, ensuring that the plating layer is uniform and has good bonding with the polymer film, which is conducive to copper deposition, avoids the phenomenon of missing plating, and makes the bonding force between the electroless copper plating layer and the polymer film >10N / cm.

[0083] (3) The method provided by the present invention has a simple process flow, low production cost and low environmental pollution. Detailed Implementation

[0084] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0085] Example 1

[0086] This embodiment provides a method for chemically plating copper on the surface of a PP film, the method comprising the following steps:

[0087] (1) A PP film with a thickness of 5 μm and a surface roughness of 0.07 μm was subjected to plasma surface modification treatment;

[0088] The plasma surface modification treatment includes: pre-treating, surface modifying and cleaning the PP film sequentially using plasma treatment;

[0089] After the plasma surface modification treatment, the surface roughness of the PP film is 0.09 μm;

[0090] The plasma treatment is performed at a pressure of 200 mTorr, a power of 5 kW, and a total gas flow rate of 2.5 L / min.

[0091] The gases used in the pretreatment, by volume percentage, comprise: 70 v / v% oxygen, 10 v / v% nitrogen, 10 v / v% argon, and 10 v / v% helium; the pretreatment temperature is 50°C and the time is 4 min.

[0092] The gases used in the surface modification process, by volume percentage, comprise: 70 v / v% oxygen, 5 v / v% nitrogen, and 25 v / v% ammonia; the surface modification temperature is 80°C, and the time is 6 min.

[0093] The cleaning process involves gases comprising, by volume percentage: 70 v / v oxygen, 10 v / v nitrogen, 10 v / v argon, and 10 v / v helium; the cleaning temperature is 90°C and the time is 3 minutes.

[0094] (2) Immerse the PP film after the plasma surface modification treatment in step (1) in the activation solution and activate it at 50°C for 2 min. Then immerse it in the reduction solution and activate and reduce it at 35°C for 2 min.

[0095] The activation solution includes a solution containing palladium ions; the concentration of palladium ions in the activation solution is 10 mg / L;

[0096] (3) The PP film after activation and reduction treatment in step (2) is immersed in a chemical copper plating solution with a stress of 60 MPa and chemical copper plating is performed at 32°C for 6 min. A chemical copper plating layer with a thickness of 0.6 μm is formed on both sides of the PP film. Then, it is washed with water and dried at 110°C for 6 min to obtain a copper-plated PP film.

[0097] Example 2

[0098] This embodiment provides a method for chemically plating copper on the surface of a PP film, the method comprising the following steps:

[0099] (1) A PP film with a thickness of 1.5 μm and a surface roughness of 0.07 μm was subjected to plasma surface modification treatment;

[0100] The plasma surface modification treatment includes: pre-treating, surface modifying and cleaning the PP film sequentially using plasma treatment;

[0101] After the plasma surface modification treatment, the surface roughness of the PP film is 0.09 μm;

[0102] The plasma treatment is performed at a pressure of 110 mTorr, a power of 3.5 kW, and a total gas flow rate of 3.5 L / min.

[0103] The gases used in the pretreatment, by volume percentage, comprise: 80 v / v% oxygen, 10 v / v% nitrogen, and 10 v / v% argon; the pretreatment temperature is 30°C and the time is 5 min.

[0104] The gases used in the surface modification process, by volume percentage, comprise: 60 v / v% oxygen, 20 v / v% nitrogen, and 20 v / v% ammonia; the surface modification temperature is 90°C and the time is 3 min.

[0105] The cleaning process involves gases comprising, by volume percentage: 80 v / v% oxygen, 10 v / v% nitrogen, and 10 v / v% argon; the cleaning temperature is 95°C and the time is 2 minutes.

[0106] (2) Immerse the PP film after plasma surface modification treatment in step (1) in the activation solution and activate it at 45°C for 5 min. Then immerse it in the reduction solution and activate and reduce it at 30°C for 3 min.

[0107] The activation solution includes a solution containing palladium ions; the concentration of palladium ions in the activation solution is 5 mg / L.

[0108] (3) The PP film after activation and reduction treatment in step (2) is immersed in a chemical copper plating solution with a stress of 40 MPa and chemical copper plating is performed at 27°C for 10 min. A chemical copper plating layer with a thickness of 0.3 μm is formed on both sides of the PP film. Then, it is washed with water and dried at 110°C for 8 min to obtain a copper-plated PP film.

[0109] Example 3

[0110] This embodiment provides a method for chemically plating copper on the surface of a PP film, the method comprising the following steps:

[0111] (1) A PP film with a thickness of 10 μm and a surface roughness of 0.05 μm was subjected to plasma surface modification treatment;

[0112] The plasma surface modification treatment includes: pre-treating, surface modifying and cleaning the PP film sequentially using plasma treatment;

[0113] After the plasma surface modification treatment, the surface roughness of the PP film is 0.07 μm;

[0114] The plasma treatment has a pressure of 280 mTorr, a power of 7 kW, and a total gas flow rate of 1.5 L / min.

[0115] The gases used in the pretreatment, by volume percentage, comprise: 70 v / v% oxygen, 10 v / v% nitrogen, 10 v / v% argon, and 10 v / v% helium; the pretreatment temperature is 60°C and the time is 52 min.

[0116] The gases used in the surface modification process, by volume percentage, comprise: 63 v / v% oxygen, 10 v / v% nitrogen, and 27 v / v% ammonia; the surface modification temperature is 90°C and the time is 8 min.

[0117] The cleaning process involves gases comprising, by volume percentage: 70 v / v oxygen, 10 v / v nitrogen, 10 v / v argon, and 10 v / v helium; the cleaning temperature is 92°C and the time is 4 minutes.

[0118] (2) Immerse the PP film after the plasma surface modification treatment in step (1) in the activation solution and activate it at 55°C for 1 min. Then immerse it in the reduction solution and activate and reduce it at 40°C for 0.7 min.

[0119] The activation solution includes a solution containing palladium ions; the concentration of palladium ions in the activation solution is 20 mg / L;

[0120] (3) The PP film after activation and reduction treatment in step (2) is immersed in a chemical copper plating solution with a stress of 90 MPa and chemical copper plating is performed at 40°C for 3 min. A chemical copper plating layer with a thickness of 1 μm is formed on both sides of the PP film. Then it is washed with water and dried at 110°C for 8 min to obtain a copper-plated PP film.

[0121] Example 4

[0122] This embodiment provides a method for chemically plating copper on the surface of a PP film. Except for the total gas flow rate of the plasma treatment in step (1) being 1 L / min, all other conditions are the same as in Example 1.

[0123] Example 5

[0124] This embodiment provides a method for chemically plating copper on the surface of a PP film. Except for the total gas flow rate of the plasma treatment in step (1) being 5 L / min, all other conditions are the same as in Example 1.

[0125] Example 6

[0126] This embodiment provides a method for chemically plating copper on the surface of a PP film. Except for the surface modification temperature of 40°C in step (1), all other conditions are the same as in Example 1.

[0127] Example 7

[0128] This embodiment provides a method for chemically plating copper on the surface of a PP film. Except for the surface modification temperature of 50°C in step (1), all other conditions are the same as in Example 1.

[0129] Example 8

[0130] This embodiment provides a method for chemically plating copper on the surface of a PP film. Except for the surface modification time of 1 min in step (1), all other conditions are the same as in Example 1.

[0131] Example 9

[0132] This embodiment provides a method for chemically plating copper on the surface of a PP film. Except for the surface modification time of 15 min in step (1), all other conditions are the same as in Example 1.

[0133] Example 10

[0134] This embodiment provides a method for chemically plating copper on the surface of a PP film. Except for the surface modification in step (1), where the gases are in the following volume proportions: 70 v / v% oxygen, 20 v / v% nitrogen and 10 v / v% ammonia, all other conditions are the same as in Example 1.

[0135] Example 11

[0136] This embodiment provides a method for chemically plating copper on the surface of a PP film. Except for the surface modification in step (1), where the gases are in the following volume proportions: 50 v / v% oxygen, 20 v / v% nitrogen and 30 v / v% ammonia, all other conditions are the same as in Example 1.

[0137] Example 12

[0138] This embodiment provides a method for chemically plating copper on the surface of a PP film. Except for the surface modification in step (1), where the gases are in the following volume proportions: 80 v / v% oxygen, 15 v / v% nitrogen and 5 v / v% ammonia, all other conditions are the same as in Example 1.

[0139] Example 13

[0140] This embodiment provides a method for chemically plating copper on the surface of a PP film. Except for the surface modification in step (1), where the gases are in the following volume proportions: 80 v / v% oxygen and 20 v / v% nitrogen, all other conditions are the same as in Example 1.

[0141] Example 14

[0142] This embodiment provides a method for chemically plating copper on the surface of a PP film. Except for the stress of the chemical copper plating solution used in step (3) being 120 MPa, all other conditions are the same as in Example 1.

[0143] Comparative Example 1

[0144] This comparative example provides a method for chemically plating copper on the surface of a PP film. Except for the absence of step (2) activation treatment and activation-reduction treatment, all other conditions are the same as in Example 1.

[0145] The mechanical properties and adhesion of the copper-plated PP films prepared in the above embodiments and comparative examples were tested, and the test results are shown in Table 1.

[0146] Table 1

[0147] Tensile strength (MPa) Elongation (%) Bonding force (N / cm) Example 1 35.2 164.5 10.3 Example 2 12.0 190.7 11.0 Example 3 43.8 112.5 10.6 Example 4 36.7 157.3 8.5 Example 5 20.8 125.3 9.2 Example 6 36.5 168.1 8.3 Example 7 36.2 170.4 9.0 Example 8 37.1 171.5 7.2 Example 9 23.6 156.4 8.7 Example 10 33.5 152.6 9.3 Example 11 32.5 147.5 8.8 Example 12 30.7 145.9 5.1 Example 13 31.8 152.4 3.4 Example 14 31.5 158.6 7.5 Comparative Example 1 36.1 168.5 Copper plating is not possible

[0148] From Table 1, we can conclude that:

[0149] (1) The copper-plated PP film prepared by the method provided in Examples 1-3 of the present invention has excellent mechanical properties, and the bonding force between the copper plating layer and the PP film is >10N / cm.

[0150] (2) Comparing Examples 1 and 4-5, it can be seen that if the total gas flow rate in the plasma treatment is too low, the number of plasmas acting on the film surface is small, resulting in a small number of polar functional groups and poor surface modification effect; if the total gas flow rate in the plasma treatment is too high, the number of plasmas acting on the film surface is too large, resulting in significant etching of the film and reduced mechanical strength.

[0151] (3) A comparison of Examples 1 and 6-7 shows that if the surface modification temperature is too low or lower than the pretreatment temperature, the surface modification effect will be poor because the molecular activity on the film surface cannot be effectively stimulated. A comparison of Examples 1 and 8-9 shows that if the surface modification time is too short, fewer polar functional groups are introduced, which cannot effectively promote the adsorption of the subsequent ionic palladium activator, resulting in the inability of the chemical copper plating reaction to proceed on the film surface. If the surface modification time is too long, the plasma will cause significant etching of the film, resulting in a decrease in mechanical strength.

[0152] (4) Comparing Example 1 and Example 10-11, it can be seen that when the volume ratio of oxygen to ammonia is (2-6):1, it is more conducive to modifying the surface of the polymer film, introducing an appropriate amount of polar functional groups, promoting the adsorption of subsequent ionic palladium activator, and improving the bonding force between the copper plating layer and the PP film.

[0153] (5) Comparing Example 1 and Example 12-13, it can be seen that if the proportion of ammonia is too low or there is no ammonia in the surface modification process, the number of -NH2 functional groups generated on the film surface is small, resulting in poor activation effect of subsequent palladium ions, which in turn leads to a decrease in the bonding force between the copper plating layer and the PP film.

[0154] (6) Comparing Example 1 and Comparative Example 1, it can be seen that chemical copper plating cannot be performed without activation and activation-reduction treatment.

[0155] The applicant declares that the detailed structural features of the present invention are illustrated through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components selected in the present invention, additions of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0156] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0157] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0158] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for electroless copper plating on the surface of a polymer film, characterized by, The method comprises the following steps: (1) performing plasma surface modification treatment on the polymer film; (2) sequentially performing activation treatment and activation reduction treatment on the polymer film after the plasma surface modification treatment in step (1); (3) performing chemical copper plating on the polymer film after the activation reduction treatment in step (2) to obtain a copper-plated polymer film; The material of the polymer film in step (1) comprises polypropylene; The plasma surface modification treatment in step (1) comprises sequentially performing pretreatment, surface modification, and cleaning on the polymer film by using plasma treatment; The gas in the surface modification comprises 50-80 v / v% oxygen, 0-20 v / v% nitrogen, and 10-30 v / v% ammonia by volume ratio; The volume ratio of oxygen to ammonia in the surface modification is (2.5-6):1; The temperature of the surface modification is 50-99 ℃, and the time is 2-10 min; The total flow rate of the gas in the plasma treatment is 1.5-3.5 L / min.

2. The method of claim 1, wherein, The thickness of the polymer film in step (1) is 1-10 μm.

3. The method of claim 1, wherein, The surface roughness of the polymer film in step (1) is less than 0.09 μm.

4. The method of claim 1, wherein, After the plasma surface modification treatment in step (1), the surface roughness of the polymer film is less than 0.1 μm.

5. The method of claim 1, wherein, The pressure of the plasma treatment is 100-300 mTorr.

6. The method of claim 1, wherein, The power of the plasma treatment is 3-7 kW.

7. The method of claim 1, wherein, The temperature of the surface modification is higher than that of the pretreatment.

8. The method of claim 1, wherein, The gas in the pretreatment comprises 60-90 v / v% oxygen, 0-40 v / v% nitrogen, 0-40 v / v% argon, and 0-40 v / v% helium by volume ratio.

9. The method of claim 1, wherein, The temperature of the pretreatment is 30-60 ℃.

10. The method of claim 1, wherein, The time of the pretreatment is 2-5 min.

11. The method of claim 1, wherein, The gas in the cleaning comprises 60-90 v / v% oxygen, 0-40 v / v% nitrogen, 0-40 v / v% argon, and 0-40 v / v% helium by volume ratio.

12. The method of claim 1, wherein, The temperature of the cleaning is 30-99 ℃.

13. The method of claim 1, wherein, The time of the cleaning is 2-5 min.

14. The method of claim 1, wherein, The activation treatment in step (2) comprises immersing the polymer film after the plasma surface modification treatment in an activation solution for activation treatment.

15. The method of claim 14, wherein, The activation solution comprises a solution containing palladium ions.

16. The method of claim 15, wherein, The concentration of palladium ions in the activation solution is 3-20 mg / L.

17. The method of claim 1, wherein, The temperature of the activation treatment in step (2) is 45-55 ℃.

18. The method of claim 1, wherein, The time of the activation treatment in step (2) is 0.5-5 min.

19. The method of claim 1, wherein, The activation reduction treatment in step (2) comprises immersing the polymer film after the activation treatment in a reduction solution for activation reduction treatment.

20. The method of claim 1, wherein, The temperature of the activation reduction treatment in step (2) is 30-40 ℃.

21. The method of claim 1, wherein, The time of the activation reduction treatment in step (2) is 0.5-3 min.

22. The method of claim 1, wherein, The chemical copper plating in step (3) comprises immersing the polymer film after the activation reduction treatment in a chemical copper plating solution for chemical copper plating to form a chemical copper plating layer on both surfaces of the polymer film.

23. The method of claim 22, wherein, The thickness of the chemical copper plating layer is 0.1-1.2 μm.

24. The method of claim 1, wherein, The temperature of the chemical copper plating in step (3) is 25-40 ℃.

25. The method of claim 1, wherein, The time of the chemical copper plating in step (3) is 2-10 min.

26. The method of claim 1, wherein, The electroless copper plating in step (3) is followed by water washing and drying in sequence.

27. The method of claim 26, wherein, The drying temperature is 100-120℃.

28. The method of claim 26, wherein, The drying time is 2-10min.

29. The method of any one of claims 1-28, wherein, The method comprises the following steps: (1) performing plasma surface modification treatment on a polymer film with a thickness of 1-10μm and a surface roughness of <0.09μm; The polymer film is made of polypropylene; The plasma surface modification treatment comprises: sequentially performing pretreatment, surface modification and cleaning on the polymer film by plasma treatment; the surface modification temperature is higher than the pretreatment temperature; After the plasma surface modification treatment, the surface roughness of the polymer film is <0.1μm; The plasma treatment is performed at a pressure of 100-300mTorr, a power of 3-7kW and a total gas flow of 1.5-3.5L / min; In the pretreatment, the gas comprises 60-90v / v% oxygen, 0-40v / v% nitrogen, 0-40v / v% argon and 0-40v / v% helium; the pretreatment temperature is 30-60℃ and the pretreatment time is 2-5min; In the surface modification, the gas comprises 50-80v / v% oxygen, 0-20v / v% nitrogen and 10-30v / v% ammonia; the surface modification temperature is 50-99℃ and the surface modification time is 2-10min; In the cleaning, the gas comprises 60-90v / v% oxygen, 0-40v / v% nitrogen, 0-40v / v% argon and 0-40v / v% helium; the cleaning temperature is 30-99℃ and the cleaning time is 2-5min; (2) soaking the polymer film after the plasma surface modification treatment in step (1) in an activation solution, performing activation treatment at 45-55℃ for 0.5-5min, then soaking in a reduction solution, performing activation reduction treatment at 30-40℃ for 0.5-3min; The activation solution comprises a solution containing palladium ions; the concentration of palladium ions in the activation solution is 3-20mg / L; (3) soaking the polymer film after the activation reduction treatment in step (2) in an electroless copper plating solution, performing electroless copper plating at 25-40℃ for 2-10min to form a copper layer with a thickness of 0.1-1.2μm on both sides of the polymer film, then performing water washing and drying in sequence to obtain a copper-plated polymer film.