A method of forming a metal plating layer on a flexible base film

Abstract

The present application relates to a kind of methods for forming metal plating on flexible base film, the method includes: (1) the upper and lower surfaces of flexible base film are coated with adhesive mixture, then first solidification and second solidification are carried out in turn, to form adhesive layer;(2) the flexible base film after second solidification of step (1) is activated in turn and is activated reduction treatment;(3) the flexible base film after activated reduction treatment of step (2) is carried out electroless copper plating, to form metal copper plating layer.The method forms adhesive layer with specific component and surface roughness on the upper and lower surfaces of flexible base film, then is activated in turn and is activated reduction treatment, effectively avoids the generation of the problem that the binding force between copper plating layer and flexible base film is poor, ensures that plating layer is uniform and well combined with flexible base film, is conducive to the deposition of copper, avoids the phenomenon of plating, so that the binding force between electroless copper plating layer and polymer film is >10N / cm.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of flexible base film processing, and particularly relates to a method for forming a metal plating layer on a flexible base film. BACKGROUND

[0002] In recent years, with the rapid development of new energy vehicles, the demand for high energy density and low cost secondary batteries in the industry is also increasing, but with the gradual miniaturization of electronic devices and the lightweighting of vehicles, the energy density of LiB needs to be further improved.

[0003] Because the traditional copper foil is heavy and has low flexibility, it has obvious disadvantages in performance, safety, service life, etc. In recent years, many studies have pointed out that composite copper material is a replaceable material. The weight of composite copper material is 1 / 2 of that of traditional copper foil, and the weight is lighter. Flexible materials such as polypropylene (PP) and polyethylene terephthalate (PET) have softness, and the composite copper material can be bent and wound according to the flexibility, which can improve the safety of lithium batteries. At the same time, the cost of composite copper material is lower, which greatly reduces the production cost of lithium batteries. However, one of the technical difficulties is that the flexible material has no active functional group and has strong hydrophobicity, and it is difficult to form a metal plating layer with excellent bonding force on the surface, which limits its application in the industrial field.

[0004] At present, in the copper plating process, an organic base layer and a colloidal palladium nanoparticle layer are usually applied on the flexible material to improve its bonding capacity, and then chemical copper plating is carried out to prepare a metal copper film. Because this preparation process has relatively low production cost, better product yield and product performance compared with vacuum or sputtering process, it has attracted widespread attention in recent years. However, the above method needs to control the amount to ensure the uniform quality of palladium nanoparticles during coating, and the bonding force of the plating layer still needs to be improved.

[0005] Therefore, it is urgent to develop a method for forming a metal plating layer on a flexible material with excellent bonding force and simple and easy-to-operate process to meet the application requirements. SUMMARY

[0006] To solve the above technical problems, the present application provides a method for forming a metal plating layer on a flexible base film, which improves the bonding force between the chemical copper plating layer and the flexible base film, ensures that the chemical copper plating layer is uniformly attached to the surface of the flexible base film, and avoids the phenomenon of missed plating.

[0007] To achieve the above technical effects, the present application adopts the following technical solutions:

[0008] The present application provides a method for forming a metal plating layer on a flexible base film, which comprises the following steps:

[0009] (1) coating the upper and lower surfaces of the flexible base film with an adhesive mixture, and then sequentially performing first curing and second curing to form an adhesive layer;

[0010] (2) sequentially performing activation treatment and activation reduction treatment on the flexible base film after the second curing of step (1);

[0011] (3) performing electroless copper plating on the flexible base film after the activation reduction treatment of step (2) to form a copper plating layer.

[0012] The method of the present application coats the upper and lower surfaces of the flexible base film with an adhesive mixture, and then sequentially performs first curing and second curing to form an adhesive layer, and then sequentially performs activation treatment, activation reduction treatment and electroless copper plating, effectively avoiding the problem of poor adhesion between the copper plating layer and the flexible base film, ensuring uniform plating and good adhesion between the plating layer and the flexible base film, facilitating copper deposition and avoiding plating defects.

[0013] It is worth noting that the adhesive mixture with a specific composition is coated on the upper and lower surfaces of the flexible base film, and then first curing and second curing are performed to form an adhesive layer with a certain roughness on the surface, which not only has strong adhesion with the flexible base film, but also promotes the adsorption of subsequent ion palladium.

[0014] As a preferred technical solution of the present application, the material of the flexible base film of step (1) includes polypropylene.

[0015] It is worth noting that PP material has no active functional groups and is highly hydrophobic, making it difficult to form a metal plating layer with good adhesion on the surface, limiting its application in the industrial field, therefore, the PP material needs to be modified.

[0016] Preferably, the thickness of the flexible base film of 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, etc., but not limited to the listed values, other values not listed within the above range are also applicable.

[0017] As a preferred technical solution of the present application, the adhesive mixture of step (1) includes an adhesive, a curing accelerator and an adhesion promoter.

[0018] Preferably, the adhesive includes an epoxy resin-based adhesive.

[0019] Preferably, the curing accelerator includes a tertiary amine curing accelerator.

[0020] In the present application, the tertiary amine curing accelerator includes any one of 2,4,6-tris(dimethylaminomethyl)phenol, benzyldimethylamine, o-hydroxybenzyl dimethylamine, bis(dimethylaminoethyl) ether, pentamethyldiethylenetriamine, N,N-dimethylcyclohexylamine, triethanolamine or triethylamine or a combination of at least two thereof.

[0021] The adhesive mixture of the present application contains a tertiary amine curing accelerator, which promotes the subsequent adsorption of ionic palladium.

[0022] Preferably, the adhesion promoter includes chlorinated polypropylene.

[0023] The adhesive mixture of the present application contains an adhesion promoter, which enhances the binding force with the flexible base film.

[0024] Preferably, the adhesive mixture includes, based on 100% by mass: adhesive 80%-90%, curing accelerator 2%-10%, adhesion promoter 2%-10%.

[0025] In the present application, the content of the adhesive in the adhesive mixture is 80%-90%, for example, it can be 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88% or 89%, etc., the content of the curing accelerator in the adhesive mixture is 2%-10%, for example, it can be 3%, 4%, 5%, 6%, 7%, 8% or 9%, etc., the content of the adhesion promoter in the adhesive mixture is 2%-10%, for example, it can be 3%, 4%, 5%, 6%, 7%, 8% or 9%, etc., but not limited to the listed values, other values not listed within the above numerical range are also applicable.

[0026] As a preferred technical solution of the present application, the first curing of step (1) is non-contact heating, and the non-contact heating mode includes any one of continuous hot air knife heating, continuous hot air circulation heating or continuous infrared heating.

[0027] Preferably, the temperature of the first curing of step (1) is 40-80℃, for example, it can be 45℃, 50℃, 55℃, 60℃, 65℃, 70℃ or 75℃, etc., but not limited to the listed values, other values not listed within the above numerical range are also applicable.

[0028] Preferably, after the first curing of step (1), a semi-cured layer with a thickness of 30-100nm is formed.

[0029] In the present application, the thickness of the semi-cured layer is 30-100nm, for example, it can be 40nm, 50nm, 60nm, 70nm, 80nm or 90nm, etc., but not limited to the listed values, other values not listed within the above numerical range are also applicable.

[0030] As a preferred technical solution of the present application, the second curing in step (1) is contact heating, and the contact heating mode includes roller heating of a heating type rolling mill.

[0031] It is worth noting that the second curing is contact heating, and the heating curing is performed by roller heating of a heating type rolling mill to form an adhesive layer with a certain roughness.

[0032] Preferably, the temperature of the second curing in step (1) is 80-100℃, and does not include 80℃, for example, it can be 82℃, 84℃, 86℃, 88℃, 90℃, 92℃, 94℃, 96℃ or 98℃, etc., but is not limited to the listed values, and other values not listed in the above value range are also applicable.

[0033] Preferably, the thickness of the adhesive layer in step (1) is 20-80nm, for example, it can be 30nm, 40nm, 50nm, 60nm or 70nm, etc., but is not limited to the listed values, and other values not listed in the above value range are also applicable.

[0034] The thickness of the adhesive layer of the present application is less than the thickness of the prepreg.

[0035] Preferably, the surface roughness of the adhesive layer in step (1) is 15-80nm, for example, it can be 20nm, 30nm, 40nm, 50nm, 60nm or 70nm, etc., but is not limited to the listed values, and other values not listed in the above value range are also applicable.

[0036] It is worth noting that the surface roughness of the adhesive layer is 0.5D≤Ra≤0.8D, where D is the thickness of the prepreg.

[0037] As a preferred technical solution of the present application, the activation treatment in step (2) includes soaking the flexible base film after the second curing in an activation liquid for activation treatment.

[0038] Preferably, the activation liquid includes a solution containing palladium ions.

[0039] Preferably, the concentration of palladium ions in the activation liquid is 3-20mg / L, for example, it can be 5mg / L, 7mg / L, 9mg / L, 10mg / L, 12mg / L, 15mg / L, 17mg / L or 19mg / L, etc., but is not limited to the listed values, and other values not listed in the above value range are also applicable.

[0040] It is worth mentioning that the present application controls the concentration of palladium ions in the activation solution within a specific range, ensuring the corresponding effect. If the concentration of palladium ions is too low, the activation effect is poor, and if the concentration of palladium ions is too high, it leads to cost waste.

[0041] Preferably, the temperature of the activation treatment in step (2) is 45-55℃, for example, it can be 46℃, 47℃, 48℃, 49℃, 50℃, 51℃, 52℃, 53℃ or 54℃, etc., but not limited to the listed values, other values not listed in the above value range are also applicable.

[0042] Preferably, the time of the activation treatment in step (2) is 0.5-5min, for example, it can be 0.7min, 1min, 2.2min, 2.5min, 2.8min, 3min, 3.2min, 3.5min, 3.8min, 4min, 4.2min, 4.5min or 4.8min, etc., but not limited to the listed values, other values not listed in the above value range are also applicable.

[0043] As a preferred technical solution of the present application, the activation and reduction treatment in step (2) comprises: soaking the flexible base film after activation treatment in a reduction solution for activation and reduction treatment.

[0044] The reduction solution used in the present application is a conventional reduction solution in the prior art, which can be selected by those skilled in the art according to actual needs.

[0045] Preferably, the temperature of the activation and reduction treatment in step (2) is 30-40℃, for example, it can be 31℃, 32℃, 33℃, 34℃, 35℃, 36℃, 37℃, 38℃ or 39℃, etc., but not limited to the listed values, other values not listed in the above value range are also applicable.

[0046] Preferably, the time of the activation and reduction treatment in step (2) is 0.5-3min, for example, it can be 0.7min, 1min, 1.2min, 1.5min, 1.7min, 1.9min, 2min, 2.2min, 2.5min, 2.7min or 2.9min, etc., but not limited to the listed values, other values not listed in the above value range are also applicable.

[0047] As a preferred technical solution of the present application, the chemical copper plating in step (3) comprises: soaking the flexible base film after activation and reduction treatment in a chemical copper plating solution for chemical copper plating, forming a copper plating layer on the upper and lower surfaces of the flexible base film.

[0048] Preferably, the stress of the electroless copper plating solution is -100MPa~100MPa, for example, it can be ±90MPa, ±80MPa, ±70MPa, ±60MPa, ±50MPa, ±40MPaa, ±30MPa, ±20MPa, ±10MPa or 0MPa, etc., but not limited to the listed values, other values not listed in the above range are also applicable.

[0049] In the present application, when the stress is a positive value, it represents tensile stress; when the stress is a negative value, it represents compressive stress.

[0050] In the present application, as long as the stress of the electroless copper plating solution is within ±100Mpa, the specific components are not specifically limited, and those skilled in the art can select according to actual needs.

[0051] Preferably, the thickness of the copper plating layer is 0.1-1.2μm, for example, it can be 0.2μm, 0.4μm, 0.5μm, 0.6μm, 0.8μm, 1.0μm or 1.1μm, etc., but not limited to the listed values, other values not listed in the above range are also applicable.

[0052] It is worth noting that the binding force between the copper plating layer formed by the present application and the flexible base film is >10N / cm.

[0053] 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 not limited to the listed values, other values not listed in the above range are also applicable.

[0054] Preferably, the time of the electroless copper plating in step (3) is 2-10min, for example, it can be 3min, 4.5min, 5min, 5.5min, 6min, 6.5min, 7min, 7.5min, 8min, 9min or 10min, etc., but not limited to the listed values, other values not listed in the above range are also applicable.

[0055] As a preferred technical solution of the present application, the electroless copper plating in step (3) further includes water washing and drying in sequence.

[0056] Preferably, the temperature of the drying is 100-120℃, for example, it can be 102℃, 105℃, 107℃, 109℃, 110℃, 112℃, 115℃, 117℃ or 119℃, etc., but not limited to the listed values, other values not listed in the above range are also applicable.

[0057] 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, etc., but not limited to the listed values, other values not listed in the above value range are also applicable.

[0058] As a preferred technical solution of the present application, the method comprises the following steps:

[0059] (1) Coating an adhesive mixture on the upper and lower surfaces of a flexible base film with a thickness of 1-10 μm, then sequentially performing first curing and second curing to form an adhesive layer with a thickness of 20-80 nm and a surface roughness of 15-80 nm;

[0060] The adhesive mixture comprises an adhesive, a curing accelerator and an adhesion accelerator; the adhesive comprises an epoxy resin-based adhesive; the curing accelerator comprises a tertiary amine-containing curing accelerator; and the adhesion accelerator comprises chlorinated polypropylene;

[0061] The first curing is non-contact heating, and the temperature of the first curing is 40-80℃; after the first curing, a semi-cured layer with a thickness of 30-100 nm is formed;

[0062] The second curing is contact heating, and the temperature of the second curing is 80-100℃, and 80℃ is not included;

[0063] (2) Soaking the flexible base film after the second curing of step (1) in an activation liquid, performing activation treatment at 45-55℃ for 0.5-5 min, then soaking in a reduction liquid, and performing activation reduction treatment at 30-40℃ for 0.5-3 min;

[0064] The activation liquid comprises a solution containing palladium ions; the concentration of palladium ions in the activation liquid is 3-20 mg / L;

[0065] (3) Soaking the flexible base film after the activation reduction treatment of step (2) in a chemical copper plating liquid with a stress of -100 MPa-100 MPa, performing chemical copper plating at 25-40℃ for 2-10 min to form a copper plating layer with a thickness of 0.1-1.2 μm on the upper and lower surfaces of the flexible base film, and then sequentially performing water washing and drying.

[0066] The numerical range of the present application includes not only the above-mentioned point values, but also any point values between the above-mentioned numerical ranges that are not listed, and due to the limited space and for the sake of simplicity, the present application does not exhaustively list the specific point values included in the range.

[0067] Compared with the prior art, the present application has the following beneficial effects:

[0068] (1) The method provided by the present application coats a specific adhesive mixture on the upper and lower surfaces of the flexible base film, and then sequentially performs first curing and second curing, so that the adhesive layer formed not only strengthens the bonding force with the flexible base film, but also promotes the subsequent adsorption of ion palladium, and at the same time, since the flexible base film does not need to be modified, the structure and mechanical properties of the flexible base film are not damaged;

[0069] (2) The method provided by the present application forms an adhesive layer with specific components and surface roughness on the upper and lower surfaces of the flexible base film, and then sequentially performs activation treatment and activation reduction treatment, which effectively avoids the problem of poor bonding force between the copper plating layer and the flexible base film, ensures that the plating layer is uniform and well bonded with the flexible base film, is conducive to copper deposition, avoids the phenomenon of plating leakage, and makes the bonding force between the electroless copper plating layer and the polymer film > 10 N / cm;

[0070] (3) The method provided by the present application has a simple process flow, low production cost, and small environmental pollution. DETAILED DESCRIPTION

[0071] In order to facilitate the understanding of the present application, the present application lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present application and should not be regarded as a specific limitation on the present application.

[0072] The present application does not specifically limit the material of the tertiary amine curing accelerator in the following examples and comparative examples, and those skilled in the art can select it according to the actual situation.

[0073] Example 1

[0074] The present embodiment provides a method for forming a metal plating layer on a flexible base film, which comprises the following steps:

[0075] (1) Coating an adhesive mixture on the upper and lower surfaces of a flexible base film with a thickness of 5 μm, and then sequentially performing first curing and second curing to form an adhesive layer with a thickness of 50 nm and a surface roughness of 42 nm;

[0076] The flexible base film is a PP film;

[0077] The adhesive mixture comprises an epoxy resin adhesive, a tertiary amine curing accelerator and chlorinated polypropylene; the adhesive mixture comprises, based on 100% by mass: epoxy resin adhesive 85%, tertiary amine curing accelerator 5%, and chlorinated polypropylene 10%;

[0078] The first curing is non-contact heating, the mode of the non-contact heating is continuous hot air circulation heating, and the temperature of the first curing is 60 DEG C; after the first curing, a semi-cured layer with a thickness of 60 nm is formed;

[0079] The second curing is contact heating, the mode of the contact heating is heated roll mill pair roller heating, and the temperature of the second curing is 90 DEG C;

[0080] (2) soaking the flexible base film after the second curing of step (1) in an activation liquid, performing activation treatment at 50 DEG C for 3 min, and then soaking in a reduction liquid, performing activation reduction treatment at 35 DEG C for 2 min;

[0081] The activation liquid comprises a solution containing palladium ions; the concentration of the palladium ions in the activation liquid is 10 mg / L;

[0082] (3) soaking the flexible base film after the activation reduction treatment of step (2) in a chemical copper plating liquid with a stress of 80 MPa, performing chemical copper plating at 34 DEG C for 6 min, forming a metal copper plating layer with a thickness of 0.7 μm on the upper and lower surfaces of the flexible base film, then performing water washing, and then drying at 110 DEG C for 6 min.

[0083] Example 2

[0084] The embodiment provides a method for forming a metal plating layer on a flexible base film, the method comprising the following steps:

[0085] (1) coating an adhesive mixture on the upper and lower surfaces of a flexible base film with a thickness of 2 μm, and then performing first curing and second curing in sequence, forming an adhesive layer with a thickness of 20 nm and a surface roughness of 15 nm;

[0086] The flexible base film is a PP film;

[0087] The adhesive mixture comprises an epoxy resin adhesive, a tertiary amine curing accelerator and chlorinated polypropylene; the adhesive mixture comprises, with 100% by mass, the epoxy resin adhesive 82%, the tertiary amine curing accelerator 9% and the chlorinated polypropylene 9%;

[0088] The first curing is non-contact heating, the mode of the non-contact heating is continuous infrared heating, and the temperature of the first curing is 42 DEG C; after the first curing, a semi-cured layer with a thickness of 32 nm is formed;

[0089] The second curing is contact heating, the mode of the contact heating is heated roll mill pair roller heating, and the temperature of the second curing is 85 DEG C;

[0090] (2) soaking the flexible base film after the second solidification in step (1) in an activation solution, performing activation treatment at 45°C for 5 min, and then soaking in a reduction solution, performing activation reduction treatment at 30°C for 3 min;

[0091] The activation solution comprises a solution containing palladium ions; the concentration of palladium ions in the activation solution is 5 mg / L;

[0092] (3) soaking the flexible base film after the activation reduction treatment in step (2) in a chemical copper plating solution with a stress of -80 MPa, performing chemical copper plating at 25°C for 10 min, forming a metal copper plating layer with a thickness of 0.2 μm on the upper and lower surfaces of the flexible base film, then performing water washing, and then drying at 110°C for 6 min.

[0093] Example 3

[0094] The present embodiment provides a method for forming a metal plating layer on a flexible base film, the method comprising the following steps:

[0095] (1) coating an adhesive mixture on the upper and lower surfaces of a flexible base film with a thickness of 10 μm, and then performing first solidification and second solidification in sequence, forming an adhesive layer with a thickness of 60 nm and a surface roughness of 64 nm;

[0096] The flexible base film is a PP film;

[0097] The adhesive mixture comprises an epoxy resin-based adhesive, a tertiary amine curing accelerator, and chlorinated polypropylene; the adhesive mixture comprises, with a mass percentage of 100%, the epoxy resin-based adhesive 90%, the tertiary amine curing accelerator 5%, and the chlorinated polypropylene 5%;

[0098] The first solidification is non-contact heating, the mode of the non-contact heating is continuous hot air knife heating, and the temperature of the first solidification is 80°C; after the first solidification, a semi-cured layer with a thickness of 80 nm is formed;

[0099] The second solidification is contact heating, the mode of the contact heating is heated roll-to-roll heating, and the temperature of the second solidification is 100°C;

[0100] (2) soaking the flexible base film after the second solidification in step (1) in an activation solution, performing activation treatment at 55°C for 1 min, and then soaking in a reduction solution, performing activation reduction treatment at 40°C for 1 min;

[0101] The activation solution comprises a solution containing palladium ions; the concentration of palladium ions in the activation solution is 20 mg / L;

[0102] (3) The flexible base film after the activation 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 40°C for 3 min to form a metal copper plating layer with a thickness of 1.1 μm on the upper and lower surfaces of the flexible base film, and then water washing is performed, followed by drying at 110°C for 6 min.

[0103] Example 4

[0104] The present example provides a method for forming a metal plating layer on a flexible base film, except that the adhesive mixture in step (1) comprises an epoxy resin adhesive and a tertiary amine curing accelerator; and the adhesive mixture comprises, based on 100% by mass: an epoxy resin adhesive 90%, a tertiary amine curing accelerator 10% in addition; and other conditions are the same as in Example 1.

[0105] Example 5

[0106] The present example provides a method for forming a metal plating layer on a flexible base film, except that the adhesive mixture in step (1) comprises an epoxy resin adhesive and chlorinated polypropylene; and the adhesive mixture comprises, based on 100% by mass: an epoxy resin adhesive 90%, chlorinated polypropylene 10% in addition; and other conditions are the same as in Example 1.

[0107] Example 6

[0108] The present example provides a method for forming a metal plating layer on a flexible base film, except that the adhesive mixture in step (1) is only an epoxy resin adhesive; and other conditions are the same as in Example 1.

[0109] Example 7

[0110] The present example provides a method for forming a metal plating layer on a flexible base film, except that the second curing in step (1) is non-contact heating, and the heating mode is continuous hot air circulation heating; and other conditions are the same as in Example 1.

[0111] Example 8

[0112] The present example provides a method for forming a metal plating layer on a flexible base film, except that the temperature of the second curing in step (1) is 70°C; and other conditions are the same as in Example 1.

[0113] Example 9

[0114] The present example provides a method for forming a metal plating layer on a flexible base film, except that the temperature of the second curing in step (1) is 120°C; and other conditions are the same as in Example 1.

[0115] Example 10

[0116] The embodiment provides a method for forming a metal plating layer on a flexible base film, wherein, in addition to the first solidification, a semi-solid layer with a thickness of 20 nm is formed, and then, after the second solidification, an adhesive layer with a thickness of 16 nm and a surface roughness of 10 nm is formed; and other conditions are the same as those in the embodiment 1.

[0117] Embodiment 11

[0118] The embodiment provides a method for forming a metal plating layer on a flexible base film, wherein, in addition to the first solidification, a semi-solid layer with a thickness of 20 nm is formed, and then, after the second solidification, an adhesive layer with a thickness of 16 nm and a surface roughness of 10 nm is formed; and other conditions are the same as those in the embodiment 1.

[0119] Embodiment 12

[0120] The embodiment provides a method for forming a metal plating layer on a flexible base film, wherein, in addition to the first solidification, a semi-solid layer with a thickness of 20 nm is formed, and then, after the second solidification, an adhesive layer with a thickness of 16 nm and a surface roughness of 10 nm is formed; and other conditions are the same as those in the embodiment 1.

[0121] Comparative Example 1

[0122] The comparative example provides a method for forming a metal plating layer on a flexible base film, wherein, in addition to the first solidification, a semi-solid layer with a thickness of 20 nm is formed, and then, after the second solidification, an adhesive layer with a thickness of 16 nm and a surface roughness of 10 nm is formed; and other conditions are the same as those in the embodiment 1.

[0123] Comparative Example 2

[0124] The comparative example provides a method for forming a metal plating layer on a flexible base film, wherein, in addition to the first solidification, a semi-solid layer with a thickness of 20 nm is formed, and then, after the second solidification, an adhesive layer with a thickness of 16 nm and a surface roughness of 10 nm is formed; and other conditions are the same as those in the embodiment 1.

[0125] The metal copper plating layer formed in the above embodiment and comparative example is subjected to a bonding force test, and the test result is shown in Table 1.

[0126] Table 1

[0127]

[0128]

[0129] From Table 1, it can be concluded that:

[0130] (1) The method provided in the embodiments 1-3 of the application is used to form a metal copper plating layer on the upper and lower surfaces of the PP film, and the bonding force between the copper plating layer and the PP film is greater than 10 N / cm.

[0131] (2) Comprehensive example 1 and examples 4-6 can be compared, if the adhesive mixture does not contain adhesion promoter, the binding force between the adhesive layer and the PP film cannot be further strengthened, resulting in the binding force between the adhesive layer and the PP film decreases, and the adhesive layer and the PP film are separated in some positions; if the adhesive mixture does not contain a curing accelerator, the subsequent ion palladium activator cannot be effectively adsorbed, resulting in the copper plating layer cannot completely cover the PP film;

[0132] (3) Comprehensive example 1 and examples 7-9 can be compared, if the second curing is non-contact heating, the adhesive layer cannot have a rough surface, resulting in the binding force between the copper plating layer and the PP film is low; if the temperature of the second curing is too low, the adhesive layer is not fully cured, the cohesive force of the adhesive layer is low, resulting in the overall binding force is low; if the temperature of the second curing is too high, the adhesive layer surface is not uniform due to the too fast curing speed, resulting in the binding force between the copper plating layer and the PP film is not uniform;

[0133] (4) Comprehensive example 1 and examples 10-11 can be compared, if the thickness of the semi-cured layer and the adhesive layer formed is too thin, the adhesive layer is easily damaged, resulting in the existence of plating leakage on the film; if the thickness of the semi-cured layer and the adhesive layer formed is too thick, the bending resistance of the PP film is reduced, and cracks appear in the plating layer after bending, affecting subsequent application;

[0134] (5) Comprehensive example 1 and comparative examples 1-2 can be compared, if the first curing is not performed, because the film surface is a flowable adhesive, in the case of not performing contact curing, even if the second curing adopts non-contact heating method, because the first curing temperature is high, the curing speed is too fast, the adhesive layer surface is not uniform, and the adhesive layer cannot have a rough surface, resulting in the binding force between the copper plating layer and the PP film is low; if the second curing is not performed, because the adhesive layer is not fully cured, the cohesive force of the adhesive layer is low, and the adhesive layer cannot have a rough surface, resulting in the overall binding force is low.

[0135] The applicant declares that the above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. It should be understood by those skilled in the art that any changes or replacements within the technical scope disclosed by the present application can be easily thought of by those skilled in the art, and all fall within the protection scope and disclosure scope of the present application.

Claims

1. A method of forming a metal plating layer on a flexible base film, characterized by, The method comprises the following steps: (1) coating an adhesive mixture on the upper and lower surfaces of a flexible base film, and then sequentially performing first curing and second curing to form an adhesive layer; The adhesive mixture comprises, with the mass percentage being 100%, 80%-90% of an epoxy resin adhesive, 2%-10% of a tertiary amine curing accelerator, and 2%-10% of chlorinated polypropylene; The first curing is non-contact heating, and the non-contact heating mode comprises any one of continuous hot air knife heating, continuous hot air circulation heating, or continuous infrared heating; The temperature of the first curing is 40-80°C; The second curing is contact heating, and the contact heating mode comprises heating type roller heating of a rolling mill; The temperature of the second curing is 80-100°C, and 80°C is excluded; (2) sequentially performing activation treatment and activation reduction treatment on the flexible base film after the second curing of step (1); (3) performing chemical copper plating on the flexible base film after the activation reduction treatment of step (2) to form a metal copper plating layer.

2. The method of claim 1, wherein, The material of the flexible base film in step (1) comprises polypropylene.

3. The method of claim 1, wherein, The thickness of the flexible base film in step (1) is 1-10 μm.

4. The method of claim 1, wherein, After the first curing of step (1), a semi-cured layer with a thickness of 30-100 nm is formed.

5. The method of claim 1, wherein, The thickness of the adhesive layer in step (1) is 20-80 nm.

6. The method of claim 1, wherein, The surface roughness of the adhesive layer in step (1) is 15-80 nm.

7. The method of claim 1, wherein, The activation treatment in step (2) comprises: soaking the flexible base film after the second curing in an activation liquid for activation treatment.

8. The method of claim 7, wherein, The activation liquid comprises a solution containing palladium ions.

9. The method of claim 7, wherein, The concentration of palladium ions in the activation liquid is 3-20 mg / L.

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

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

12. The method of claim 1, wherein, The activation reduction treatment in step (2) comprises: soaking the flexible base film after the activation treatment in a reduction liquid for activation reduction treatment.

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

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

15. The method of claim 1, wherein, The chemical copper plating in step (3) comprises: soaking the flexible base film after the activation reduction treatment in a chemical copper plating liquid for chemical copper plating to form a metal copper plating layer on the upper and lower surfaces of the flexible base film.

16. The method of claim 15, wherein, The stress of the chemical copper plating liquid is -100 MPa~100 MPa.

17. The method of claim 15, wherein, The thickness of the metal copper plating layer is 0.1-1.2 μm.

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

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

20. The method of claim 1, wherein, The chemical copper plating in step (3) further comprises sequentially performing water washing and drying.

21. The method of claim 20, wherein, The temperature of the drying is 100-120°C.

22. The method of claim 20, wherein, The time of the drying is 2-10 min.

23. The method of claim 1, wherein, The method comprises the following steps: (1) coating an adhesive mixture on the upper and lower surfaces of a flexible base film with a thickness of 1-10 μm, and then sequentially performing first curing and second curing to form an adhesive layer with a thickness of 20-80 nm and a surface roughness of 15-80 nm; The first curing is non-contact heating, and the temperature of the first curing is 40-80℃; after the first curing, a semi-cured layer with a thickness of 30-100nm is formed; The second curing is contact heating, and the temperature of the second curing is 80-100℃, and 80℃ is excluded; (2) soaking the flexible base film after the second curing in step (1) in an activation liquid, and performing activation treatment at 45-55℃ for 0.5-5min, and then soaking in a reduction liquid, and performing activation reduction treatment at 30-40℃ for 0.5-3min; The activation liquid comprises a solution containing palladium ions; the concentration of palladium ions in the activation liquid is 3-20mg / L; (3) soaking the flexible base film after the activation reduction treatment in step (2) in a chemical copper plating liquid with a stress of-100MPa~100MPa, and performing chemical copper plating at 25-40℃ for 2-10min, forming a metal copper plating layer with a thickness of 0.1-1.2μm on the upper and lower surfaces of the flexible base film, and then sequentially performing water washing and drying.

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