An online coating composite copper foil film and a method for manufacturing the same

Abstract

The application discloses an online coating composite copper foil film and a preparation method thereof. The online coating composite copper foil film is composed of a substrate layer, online coating layers formed on both sides of the substrate layer, and a conductive layer attached to the outer side of the online coating layers. The online coating layer is uniformly mixed by acrylic resin, metal copper nanoparticles with a particle size of 5-10 nm, 1,4-dioxane, polyethylene oxide, and ethylene-vinyl acetate copolymer to form a primer liquid, and then is cured by online coating to form. The preparation method comprises the following steps: the substrate layer is made of a polyester film to which a polyester functional master batch is added; the online coating layers are formed on both sides of the substrate layer by an online coating process while the substrate layer is formed; and finally, the conductive layer is formed on the outer side of the online coating layers. The application replaces the corona layer and the barrier layer by the online coating layer, simplifies the processing technology, reduces the equipment demand, and can obtain the performance effect equivalent to that of the corona layer and the barrier layer.

Description

TECHNICAL FIELD

[0001] The present application relates to the current collector for conducting electricity in lithium ion batteries, in particular to a composite copper foil film that can be used as the negative current collector of lithium ion batteries, and in particular to an in-line coated composite copper foil film and a method for preparing the same. BACKGROUND

[0002] The current collector in lithium ion batteries is composed of a metal foil film for conducting electricity, and its main function is to carry the electrode materials of the positive and negative electrodes, and to collect current and conduct electrons. The commonly used positive current collector is aluminum foil, and the commonly used negative current collector is copper foil. The aluminum foil and copper foil used as the current collector are mainly used for conducting electricity and do not participate in the active reaction, so their thickness has been reduced to the strength limit under the demand for improving the energy density of the battery, and there is no space for further thinning. By referring to the composite metal film in the prior art, a composite metal film has appeared, which has a non-metallic base material as the base material, and forms a conductive layer on both sides of the base material.

[0003] CN 114481080 A discloses a vacuum plating and water plating integrated equipment and a production method of ultra-thin copper foil. The equipment includes a vacuum cavity, a winding device and an electroplating device. The winding device is used for winding the film, the vacuum cavity is used for vacuum evaporation of the film in the winding device, and the electroplating device is used for electroplating the film after evaporation. The copper foil of the prior art needs to evaporate the target material into a gas at high temperature and then attach it to the surface of the non-metallic base material layer. The higher the evaporation temperature of the target material, the more likely the base material layer will be broken or burned. Therefore, the prior art generally produces composite aluminum foil by evaporation, and there are few cases of composite copper foil prepared by evaporation, because the evaporation temperature of copper is higher. The higher the evaporation temperature of the target material, the faster the base material layer needs to run, so the copper layer formed by evaporation will be thinner, and the conductivity of the copper foil will also be poorer, which is not suitable for use as a current collector for lithium ion batteries. In addition, since the film needs to be run at a relatively fast speed during evaporation, the copper layer obtained by evaporation not only has difficulty in increasing the thickness, but also has poor density and uniformity, and is prone to falling off. In addition, due to the defects such as thickness and density of the copper layer obtained by evaporation, the sheet resistance is large, and the energy consumption of the subsequent electroplating process is also high.

[0004] In addition, another reason why the metal layer of the composite aluminum foil is easy to fall off is that the surface structure of the non-metallic base material layer used to support the metal layer is not uniform, resulting in insufficient adhesion of the metal layer on the base material layer. In order to alleviate the influence of long-time high-temperature baking on the surface performance of the base material layer, it is necessary to gradually stack the metal layer several times at intervals, and the various structural performance defects of the base material layer will be amplified by the metal layer formed by stacking, so that the existing composite metal foil and its preparation process are difficult to be applied to the production of composite copper foil film that can be used as a current collector. SUMMARY

[0005] The technical problem to be solved by the present application is to provide an online coating composite copper foil film and a preparation method thereof to reduce or avoid the problems mentioned above.

[0006] To solve the above technical problem, the present application provides an online coating composite copper foil film, which is composed of a substrate layer, online coating layers formed on both sides of the substrate layer, and conductive layers attached to the outer sides of the online coating layers, wherein the online coating layer is uniformly mixed with acrylic resin, metal copper nanoparticles with a particle size of 5-10 nm, 1,4-dioxane, polyethylene oxide, and ethylene-vinyl acetate copolymer to form a primer solution, and then formed by online coating and curing.

[0007] Preferably, the mass ratio of each component of the online coating layer is 100:(5-10):(20-30):(10-15):(5-10) for acrylic resin:metal copper nanoparticles:1,4-dioxane:polyethylene oxide:ethylene-vinyl acetate copolymer, respectively.

[0008] Preferably, the thickness of the online coating layer is 0.3-0.5 μm.

[0009] Preferably, the conductive layer comprises, from the inside out, a metal copper sputtering layer, a metal copper electroplating layer, and a protective layer; wherein the metal copper sputtering layer is a layer of metal copper with a thickness of 5-15 nm formed on both sides of the surface of the substrate layer by a vacuum sputtering process, the metal copper electroplating layer is a layer of metal copper with a thickness of 100-500 nm formed on the outer surface of the metal copper sputtering layer by a water electroplating process, and the protective layer is a dense protective layer formed after passivation treatment of the outer surface of the metal copper electroplating layer; the protective layer is a layer of 5-15 nm of metal chromium protective layer formed by an electroplating process.

[0010] Preferably, the thickness of the metal copper sputtering layer is 5-8 nm, the thickness of the metal copper electroplating layer is 300-400 nm, and the thickness of the metal chromium protective layer is 5-8 nm.

[0011] Preferably, the substrate layer is made of a polyester film added with polyester functional masterbatch, the polyester film is a single-layer polyester film containing 5-20 wt% of polyester functional masterbatch, or a three-layer structure polyester film containing A layer and C layer with 5-20 wt% of polyester functional masterbatch, wherein the polyester functional masterbatch is prepared from raw materials including the following weight parts: poly-m-xylylene diamine 30-50 parts by weight, cobalt neodecanoate 1-3 parts by weight, dibutyl hydroxytoluene 3-5 parts by weight, 1,4-diiodobenzene 5-10 parts by weight, silicon dioxide 20-30 parts by weight, and PET 50-100 parts by weight.

[0012] The application further provides a preparation method of the online-coated composite copper foil film, which is composed of a substrate layer, online-coated layers formed on both sides of the substrate layer, and a conductive layer attached to the outer side of the online-coated layers, and the preparation method comprises the following steps: the substrate layer is made of a polyester film to which a polyester functional masterbatch is added; the online-coated layers are formed on both sides of the substrate layer by an online-coating process while the substrate layer is formed; and finally, the conductive layer is formed on the outer side of the online-coated layers.

[0013] Preferably, the preparation method further comprises a preparation step of the polyester functional masterbatch: 50-100 parts by weight of powdered PET, 20-30 parts by weight of nano-silicon dioxide, 30-50 parts by weight of powdered poly-m-xylylene diamide, 1-3 parts by weight of powdered cobalt neodecanoate, 3-5 parts by weight of powdered dibutyl hydroxyl toluene, and 5-10 parts by weight of powdered 1,4-diiodobenzene are added into a high-speed mixer for pre-dispersed mixing at a rotation speed of 1500-2000 rpm for 30-60 minutes to form a mixture; then the mixture is melt-extruded by a double-screw extruder, and then water-cooled to be granulated or sliced to obtain the polyester functional masterbatch.

[0014] Preferably, the conductive layer comprises, from inside to outside, a metal copper sputtering layer, a metal copper electroplating layer, and a protective layer; wherein the formation step of the conductive layer comprises: forming the metal copper sputtering layer on the outer side of the online-coated layer by a vacuum sputtering process; growing the metal copper electroplating layer on the outer surface of the metal copper sputtering layer by a water electroplating process; and forming the protective layer on the outer surface of the metal copper electroplating layer by an electroplating process.

[0015] The application replaces the corona layer and the barrier layer with the online-coated layer, simplifies the processing technology, reduces the equipment requirements, and can obtain the performance effect comparable to that of the corona layer and the barrier layer. BRIEF DESCRIPTION OF DRAWINGS

[0016] The following drawings are merely intended to schematically illustrate and explain the application, and do not limit the scope of the application.

[0017] Figure 1 Fig. 1 shows a structural schematic diagram of a composite copper foil film according to an embodiment of the application.

[0018] Figure 2 Fig. 2 shows a structural schematic diagram of a composite copper foil film according to another embodiment of the application.

[0019] Figure 3 Fig. 3 shows a structural schematic diagram of an online-coated composite copper foil film according to still another embodiment of the application. DETAILED DESCRIPTION

[0020] In order to make the technical features, objectives and effects of the present application more clearly understood, the specific embodiments of the present application will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals.

[0021] As shown in the drawings, the present application proposes a composite copper foil film which can be used as the negative electrode current collector of lithium ion battery, the composite copper foil film is composed of a substrate layer 1 and a conductive layer 2 attached to both sides of the substrate layer 1, the conductive layer 2 is mainly composed of metal copper. As mentioned before, since the evaporation temperature of metal copper is high, if it is attached to the surface of the substrate layer 1 composed of polymer material by evaporation, it will destroy the uniformity of the surface structure of the substrate layer 1, and it is difficult to obtain the thickness required for sufficient electrical performance, and the thicker the stack is, the more likely it is to fall off and powder, which is not suitable for use as a negative electrode current collector.

[0022] Therefore, the present application proposes a composite copper foil film, in which the conductive layer 2 adopts a multi-layer conductive structure, in the specific embodiment shown in the drawings, the conductive layer 2 includes a metal copper sputtering layer 21, a metal copper electroplating layer 22 and a protective layer 23 from inside to outside. Among them, the metal copper sputtering layer 21 is a layer of metal copper with a thickness of 5-15 nm formed on both sides of the surface of the substrate layer 1 by vacuum sputtering process, the metal copper electroplating layer 22 is a layer of metal copper with a thickness of 100-500 nm formed on the outer surface of the metal copper sputtering layer 21 by water electroplating process, and the protective layer 23 is a dense protective layer formed by passivation treatment on the outer surface of the metal copper electroplating layer 22 by electroplating or chemical etching process. Preferably, the protective layer 23 is a layer of 5-15 nm of metal chromium protective layer formed by electroplating process. More preferably, the thickness of the metal copper sputtering layer 21 is 5-8 nm, the thickness of the metal copper electroplating layer 22 is 300-400 nm, and the thickness of the protective layer 23 is 5-8 nm.

[0023] In the composite copper foil film of the present application, the density and adhesion of the metal copper sputtering layer formed by vacuum sputtering process are much better than those of the evaporation process, and since the required thickness is very thin, the running speed of the substrate layer can be very fast, basically eliminating the possibility of defects such as melting or burning of the substrate layer. Although the thickness of the metal copper sputtering layer is very thin, it can provide basic conductive performance, so that a thicker layer of metal copper can be grown on its surface by water electroplating. By combining vacuum sputtering process and water electroplating process, the present application can obtain excellent electrical performance and adhesion without damaging the surface structure of the substrate layer, which will be further described below.

[0024] In addition, in order to avoid the problem of insufficient adhesion of the copper layer caused by uneven surface structure of the substrate layer, the application also proposes an improved substrate layer 1. In one embodiment of the application, the substrate layer 1 of the application is made of polyester film added with polyester functional masterbatch. The substrate layer 1 can be a single-layer structure polyester film added with polyester functional masterbatch ( Figure 1 ), or a three-layer structure polyester film containing A layer, B layer and C layer, with the surface layer added with the polyester functional masterbatch ( Figure 2 ).

[0025] The polyester referred to in the application is a polyester formed from one or more than two kinds of polybasic carboxylic acids and their ester-forming derivatives, and one or more than two kinds of polyhydric alcohols; or a polyester formed from hydroxyl carboxylic acid and its ester-forming derivatives; or a polyester formed from cyclic ester. The polyester can be manufactured according to the known methods. For example, the preparation of PET can be obtained by the following methods: esterification of terephthalic acid with ethylene glycol followed by polycondensation; or ester exchange reaction of alkyl ester of terephthalic acid such as dimethyl terephthalate with ethylene glycol followed by polycondensation. The polyester of the application is preferably PET.

[0026] In one embodiment, the polyester film constituting the substrate layer 1 is a single-layer polyester film containing 5-20 wt% of polyester functional masterbatch, or a three-layer structure polyester film containing 5-20 wt% of polyester functional masterbatch in A layer and C layer, which is prepared from the following raw materials: poly-m-xylylene diamide 30-50 parts by weight, cobalt neodecanoate 1-3 parts by weight, dibutyl hydroxytoluene 3-5 parts by weight, 1,4-diiodobenzene 5-10 parts by weight, silicon dioxide 20-30 parts by weight, and PET 50-100 parts by weight.

[0027] The polyester functional masterbatch of the application can be prepared in the form of granules or slices, and added to ordinary polyester in the process of producing polyester film to obtain the substrate layer 1 of the application. For example, 80-95 wt% of polyester without other ingredients can be melt-blended with 5-20 wt% of the polyester functional masterbatch of the application, and then a single-layer structure substrate layer 1 can be produced by stretching or other processes, or the surface structure of the substrate layer 1 of the application can be obtained by a multi-layer co-extrusion process.

[0028] Each raw material component of the polyester functional masterbatch of the application can be uniformly mixed in the form of granules, and then the polyester functional masterbatch of the application can be obtained by extrusion and granulation using equipment such as an extruder.

[0029] In one embodiment, 50-100 parts by weight of powdered PET, 20-30 parts by weight of nano-silica, 30-50 parts by weight of powdered poly-m-xylylene diamide, 1-3 parts by weight of powdered cobalt neodecanoate, 3-5 parts by weight of powdered dibutyl hydroxytoluene, and 5-10 parts by weight of powdered 1,4-diiodobenzene can be pre-dispersed and mixed in a high-speed mixer at a speed of 1500-2000 rpm for 30-60 minutes at room temperature to form a mixture. The mixture is then melt-extruded through a twin-screw extruder, and then water-cooled and granulated or sliced to obtain the polyester functional masterbatch.

[0030] In another embodiment, for example, after the polyester functional masterbatch is obtained in the form of a slice, 5-20 wt% of the polyester functional masterbatch can be added to 80-95 wt% of PET particles and uniformly mixed, and the two can be melt-blended, and finally a single-layer substrate layer 1 can be produced through a stretching process or a three-layer substrate layer 1 surface layer structure can be obtained through a multi-layer co-extrusion process.

[0031] The following will further illustrate the method for preparing the polyester film for the composite copper foil film of the present application by taking a single-layer polyester film as an example. The method for preparing the polyester film for the composite copper foil film of the present application comprises the following steps:

[0032] The following components in the following weight ratio: 80-95 wt% of PET resin and 5-20 wt% of polyester functional masterbatch are respectively weighed by an electronic scale, mixed in a mixing bin to form a mixture.

[0033] The mixture is then fed into an exhaust twin-screw extruder, and the temperature of the twin-screw extruder is adjusted to 270-280°C.

[0034] After the material is melted in the extruder, it is filtered and extruded into a thick slice. The thickness and profile of the thick slice can be adjusted by adjusting the extrusion amount of the extruder, the casting roll speed, and the die opening.

[0035] The thick slice is preheated at a temperature of 50-90°C, fed into an infrared heating zone at a temperature of 300-500°C, and stretched longitudinally at a linear speed of 40-150 m / min, with a longitudinal stretching ratio of 4.0, to obtain a stretched slice.

[0036] The stretched slice is preheated at a temperature of 90-120°C, stretched transversely at a temperature of 100-160°C, with a transverse stretching ratio of 3.8. The stretched slice is then set at a temperature of 160-240°C, and then cooled at a temperature of 100-50°C to obtain the polyester film for the composite copper foil film.

[0037] The obtained polyester film has a thickness of 6-10 μm.

[0038] The following takes the three-layer polyester film as an example to further illustrate the preparation method of the polyester film for the composite copper foil film. The preparation method of the polyester film for the composite copper foil film comprises the following steps:

[0039] The components in the following weight ratio: 80-95wt% of PET resin, 5-20wt% of polyester functional masterbatch are respectively weighed by an electronic scale, mixed in a mixing bin to prepare a mixed material.

[0040] Then the mixed material enters the exhaust type double screw extruder E.

[0041] 100% of the PET resin is put into a pre-crystallizer to pre-crystallize at a temperature of 160°C for 15 minutes, and then the PET material enters a drying tower to be dried at a temperature of 160°C for 6 hours, and then enters the single screw extruder F.

[0042] The temperature of the double screw extruders E and F is adjusted to 270-280°C.

[0043] After the material is melted in the two extruders, the material extruded by the double screw extruder E is used as the surface A layer and the C layer, the material extruded by the single screw extruder F is used as the middle B layer, and a three-layer composite thick sheet is prepared through a multi-layer co-extrusion process. The thickness and profile of the thick sheet can be adjusted by the extrusion amount of the extruder, the casting roll speed and the die opening.

[0044] The above thick sheet is preheated at a temperature of 50-90°C, enters an infrared heating zone at a temperature of 300-500°C, and is stretched longitudinally at a line speed of 40-150 m / min, and the longitudinal stretching ratio is 4.0, to obtain a stretched sheet.

[0045] The stretched sheet is preheated at a temperature of 90-120°C, stretched transversely at a temperature of 100-160°C, and the transverse stretching ratio is 3.8. Then it is set at a temperature of 160-240°C, and then cooled at a temperature of 100-50°C to prepare the polyester film with a three-layer structure.

[0046] The thickness of the prepared polyester film is 6-10 μm, wherein the thickness of the A layer is 1-2 μm, the thickness of the B layer is 2-8 μm, and the thickness of the C layer is 1-2 μm.

[0047] Examples 1-5

[0048] According to the weight ratio of the raw materials in the following table, polyester functional masterbatch chips are prepared, and then ordinary PET resin is prepared to obtain a single-layer polyester film for the composite copper foil film.

[0049] Example 1 Example 2 Example 3 Example 4 Example 5 Poly-m-xylylene diamide 30 35 40 45 50 Cobalt neodecanoate 1 1.5 2 2.5 3 Butylated hydroxytoluene 3 3.5 4 4.5 5 1,4-diiodobenzene 5 7 7.5 8 10 Silicon dioxide 20 22 25 27 30 PET 50 65 75 85 100 Amount of slice to make a single substrate layer 5 wt% 10 wt% 13 wt% 15 wt% 20 wt% Substrate layer thickness μm 6 7 8 9 10

[0050] Comparative Examples 6-10

[0051] By the same method as the above examples, the following raw material weight parts ratio was prepared as a comparative polyester film.

[0052]

[0053]

[0054] The performance parameters of each polyester film prepared were tested respectively, and the 8μm thick film prepared by pure PET without adding any functional masterbatch was compared, and each performance parameter is shown in the following table.

[0055]

[0056] The metal copper sputtering layer was formed on the two sides of the polyester film described in the above table by vacuum sputtering process, and the thickness of the two sides of the metal copper layer was controlled to be 5nm, and the surface crack parameters of the prepared film were tested.

[0057]

[0058]

[0059] From the performance parameters of the above film layer and the crack of the metal plating layer, it can be seen that the porosity, water absorption, oxygen transmission rate and other performances of the polyester film prepared by adding the polyester functional masterbatch of the application are greatly improved, and no obvious crack propagation is seen after forming the metal copper conductive layer.

[0060] Further, the resistivity difference of the metal copper sputtering layer on the two sides of the polyester film shown in the above table was tested, as shown in the following table.

[0061]

[0062] The resistivity difference of the metal copper sputtering layer formed on the polyester film prepared by adding the polyester functional masterbatch of the application is obviously smaller than that of the film without adding the functional masterbatch, indicating that the structure on both sides has more excellent consistency.

[0063] Further, since the application needs to first form a metal copper sputtering layer 21 on the surface of the substrate layer 1, the substrate layer 1 needs to be controlled at a lower temperature during sputtering. Although the improved polyester film of the substrate layer 1 has excellent porosity, water absorption, oxygen transmission rate and other performances, it still needs to prevent the problem of water absorption on the surface of the polyester film at low temperature and then release water during sputtering to interfere with the vacuum degree.

[0064] Therefore, in one embodiment not shown, in order to avoid the moisture absorption and release of the substrate layer 1 during sputtering, a barrier layer is formed on the outer side of the substrate layer 1 between the conductive layer 2 and the substrate layer 1 by sputtering, so as to form a covering isolation on the surface of the substrate layer 1 and form a hydrophobic structure on the surface of the substrate layer 1. Since the thickness of the barrier layer is very small, in order to improve the adhesion of the barrier layer on the surface of the substrate layer 1, the surface of the substrate layer 1 is subjected to corona treatment before the barrier layer is formed by sputtering, so as to form a 1-2 nm thick corona layer on the surface of the substrate layer 1, and then the barrier layer is formed on the outer side of the corona layer.

[0065] The polyester film prepared in Embodiment 1-5 is used as the substrate layer, and is subjected to corona treatment, sputtering of a barrier layer, sputtering of a metal copper sputtering layer, electroplating of a metal copper electroplating layer, and electroplating of a protective layer, respectively, to obtain a composite copper foil film with the following parameters.

[0066]

[0067] It can be seen from the measured parameters that the composite copper foil film provided with the corona layer and the barrier layer has excellent electrical performance, and the adhesion of the conductive layer is extremely strong, and the conventional use almost does not cause the peeling of the conductive layer.

[0068] Although the corona treatment and the sputtering of the barrier layer can improve the performance of the composite copper foil film, the corona treatment needs to be performed on the polyester film separately, and the surface adhesion of the formed corona layer gradually decreases over time. Therefore, the corona treatment and the subsequent sputtering of the barrier layer need to be performed at a short interval, otherwise it is difficult to achieve a controllable effect. In order to achieve the ability of performing the treatment at a short interval, a special corona and sputtering integrated device is needed, and the cost of the device is very high. There are only a few such devices in the country, and it is difficult to improve the production efficiency and yield.

[0069] Figure 3 An improved structure of an online coated composite copper foil film is shown in the figure. The online coated composite copper foil film of the embodiment is composed of a substrate layer 1, online coated layers 12 formed on both sides of the substrate layer 1, and a conductive layer 2 attached to the outer side of the online coated layers 12. The conductive layer 2 of the embodiment includes, from the inside to the outside, a metal copper sputtering layer 21, a metal copper electroplating layer 22, and a protective layer 23, which are the same as in the previous embodiments. The metal copper sputtering layer 21 is a layer of metal copper with a thickness of 5-15 nm formed on both surfaces of the substrate layer by a vacuum sputtering process. The metal copper electroplating layer 22 is a layer of metal copper with a thickness of 100-500 nm grown on the outer surface of the metal copper sputtering layer 21 by a water electroplating process. The protective layer 23 is a dense protective layer formed on the outer surface of the metal copper electroplating layer 22 after passivation treatment. The protective layer 23 is a 5-15 nm thick metal chromium protective layer formed by an electroplating process.

[0070] Figure 3 The embodiment focuses on forming an online coating layer 12 on both sides of the substrate layer 1, replacing the previously mentioned unillustrated embodiment's corona layer and barrier layer, simplifying the processing procedure, reducing equipment requirements, and obtaining equivalent performance effects. The structure and process other than online coating are the same as the previously mentioned embodiment, and the same content will not be described one by one.

[0071] Online coating can directly coat chemicals on the substrate layer through an online coating machine during the production process of the substrate layer, to obtain the same technical effects as setting the corona layer and the barrier layer. Unlike the setting of the corona layer and the barrier layer, online coating can be directly formed in the later stage of the production process of the substrate layer, without the need to re-unwind the roll material, nor the need for a dedicated corona and sputtering integrated device, with uniform coating, fast speed, high efficiency, and low cost.

[0072] In this application, the primer liquid constituting the online coating layer 12 can be coated onto the thick sheet before or during the stretching of the polyester film constituting the substrate layer, and then the thick sheet is stretched into a film of the required thickness, and the primer liquid coated on the surface of the thick sheet is thinned and solidified together with the high temperature during the stretching process to form the online coating layer 12.

[0073] In a specific embodiment, the online coating layer 12 is uniformly mixed from acrylic resin, metal copper nanoparticles with a particle size of 5-10 nm, 1,4-dioxane, polyethylene oxide, and ethylene-vinyl acetate copolymer to form a primer liquid, and then solidified by online coating. Preferably, the thickness of the formed online coating layer 12 is 0.3-0.5 μm.

[0074] Specifically, the mass ratio of each component of the online coating layer 12 is acrylic resin: metal copper nanoparticles: 1,4-dioxane: polyethylene oxide: ethylene-vinyl acetate copolymer is 100:(5-10):(20-30):(10-15):(5-10).

[0075] Among them, the ethylene-vinyl acetate copolymer can be selected from the ethylene-vinyl acetate copolymer produced by Japan Sumitomo Company with the brand Evaflex 550, and the mass percentage of the contained vinyl acetate polymer is 14%.

[0076] According to the weight ratio of the raw materials in the following table, the online coating layer is prepared on the substrate layer prepared in Examples 1-5.

[0077] Example 1 Example 2 Example 3 Example 4 Example 5 Acrylic resin 100 100 100 100 100 Metallic copper nanoparticles 5 6.5 7.5 8.5 10 1,4-dioxane 20 22 25 28 30 Polyethylene oxide 10 12 13 14 15 Ethylene-vinyl acetate copolymer 5 6 7.5 8 10 Thickness (nm) 300 350 400 450 500

[0078] The polyester film prepared in the same manner as in Examples 1-5 was used as the base layer, and was subjected to on-line coating, sputtering of a copper sputtering layer, electroplating of a copper electroplating layer, and electroplating of a protective layer, to produce a composite copper foil film having the following parameters.

[0079]

[0080] As can be seen from the measured parameters, the on-line coated composite copper foil film of the present application has the same technical effect as the previous technique of providing a corona layer and a barrier layer, and also has excellent electrical properties, and the adhesion of the conductive layer is also very strong, and the conductive layer will almost never peel off in normal use.

[0081] The method for preparing the on-line coated composite copper foil film of the present application will be further described below.

[0082] As described above, the on-line coated composite copper foil film of the present application is composed of a base layer, on-line coated layers formed on both sides of the base layer, and a conductive layer attached to the outer side of the on-line coated layers, and therefore the method for preparing the on-line coated composite copper foil film of the present application includes the following steps: first, the base layer is prepared from a polyester film to which a polyester functional masterbatch is added. The method steps for preparing the base layer have been described in detail above and will not be repeated here.

[0083] The on-line coated layers are formed on both sides of the base layer by on-line coating process at the same time as the base layer is formed; and finally the conductive layer is formed on the outer side of the on-line coated layers.

[0084] Further, as described above, the conductive layer includes, in order from the inside to the outside, a copper sputtering layer, a copper electroplating layer, and a protective layer. Therefore, the step of forming the conductive layer includes: forming a copper sputtering layer on the outer side of the on-line coated layers by vacuum sputtering process; growing a copper electroplating layer on the outer surface of the copper sputtering layer by aqueous electroplating process; and forming a protective layer on the outer surface of the copper electroplating layer by electroplating process.

[0085] Those skilled in the art should understand that, although the present application is described in the manner of multiple embodiments, not every embodiment contains only one independent technical solution. The description in the specification is merely for the sake of clarity, those skilled in the art should understand the specification as a whole and understand the technical solutions involved in each embodiment as being combinable into different embodiments to understand the scope of protection of the present application.

[0086] The above merely illustrates the specific embodiments of the present application, and is not intended to limit the scope of the present application. Any equivalent changes, modifications and combinations made by those skilled in the art without departing from the concept and principles of the present application shall fall within the scope of protection of the present application.

Claims

1. An online coated composite copper foil film, comprising a substrate layer (1), online coated layers (12) formed on both sides of the substrate layer (1), and a conductive layer (2) attached to the outer side of the online coated layers (12), characterized in that, The online coating layer (12) is formed by uniformly mixing acrylic resin, copper nanoparticles with a particle size of 5-10 nm, 1,4-dioxane, polyethylene oxide, and ethylene-vinyl acetate copolymer into a base coating liquid, and then curing it through online coating; the substrate layer (1) is made of polyester film with added polyester functional masterbatch, which is prepared from raw materials including the following parts by weight: 30-50 parts by weight of poly(isophthalamide), 1-3 parts by weight of cobalt neodecanoate, 3-5 parts by weight of butylated hydroxytoluene, 5-10 parts by weight of 1,4-diiodobenzene, 20-30 parts by weight of silica, and 50-100 parts by weight of PET.

2. The online coated composite copper foil film as described in claim 1, characterized in that, The mass ratio of each component of the online coating layer (12) is as follows: acrylic resin: copper nanoparticles: 1,4-dioxane: polyethylene oxide: ethylene-vinyl acetate copolymer is 100: (5~10): (20~30): (10~15): (5~10).

3. The online coated composite copper foil film as described in claim 1, characterized in that, The thickness of the online coating layer (12) is 0.3-0.5 μm.

4. The online coated composite copper foil film as described in any one of claims 1-3, characterized in that, The conductive layer (2) includes, from the inside out, a copper sputtering layer (21), a copper electroplating layer (22), and a protective layer (23); wherein, the copper sputtering layer (21) is a layer of copper with a thickness of 5-15nm formed on both sides of the substrate layer by vacuum sputtering process, the copper electroplating layer (22) is a layer of copper with a thickness of 100-500nm grown on the outer surface of the copper sputtering layer (21) by water electroplating process, and the protective layer (23) is a dense protective layer formed after passivating the outer surface of the copper electroplating layer (22); the protective layer (23) is a 5-15nm chromium protective layer formed by electroplating process.

5. The online coated composite copper foil film as described in claim 4, characterized in that, The thickness of the sputtered copper layer is 5-8 nm, the thickness of the electroplated copper layer is 300-400 nm, and the thickness of the chromium protective layer is 5-8 nm.

6. The online coated composite copper foil film as described in any one of claims 1-3, characterized in that, The polyester film constituting the substrate layer (1) is a single-layer polyester film containing 5 to 20 wt% polyester functional masterbatch, or a three-layer polyester film containing 5 to 20 wt% polyester functional masterbatch in layers A and C, comprising layers A, B, and C.

7. A method for preparing an online coated composite copper foil film as described in claim 1, comprising a substrate layer (1), an online coating layer (12) formed on both sides of the substrate layer (1), and a conductive layer (2) attached to the outside of the online coating layer (12), the preparation method comprising the following steps: preparing a substrate layer (1) from a polyester film with added polyester functional masterbatch; simultaneously forming the substrate layer (1), forming an online coating layer (12) on both sides of the substrate layer (1) by an online coating process; and finally forming the conductive layer (2) on the outside of the online coating layer (12); wherein the polyester functional masterbatch is prepared from raw materials comprising the following parts by weight: 30-50 parts by weight of poly(isophthalamide), 1-3 parts by weight of cobalt neodecanoate, 3-5 parts by weight of butylated hydroxytoluene, 5-10 parts by weight of 1,4-diiodobenzene, 20-30 parts by weight of silica, and 50-100 parts by weight of PET.

8. The preparation method according to claim 7, further comprising the preparation step of the polyester functional masterbatch: at room temperature, 50-100 parts by weight of powdered PET, 20-30 parts by weight of nano-silica, 30-50 parts by weight of powdered poly(isophthalamide), 1-3 parts by weight of powdered cobalt neodecanoate, 3-5 parts by weight of powdered dibutylhydroxytoluene, and 5-10 parts by weight of powdered 1,4-diiodobenzene are added to a high-speed mixer for pre-dispersion and mixing at a speed of 1500-2000 rpm for 30-60 minutes to form a mixture; then the mixture is melt-extruded through a twin-screw extruder, followed by water-cooled granulation or slicing to obtain the polyester functional masterbatch.

9. The preparation method according to claim 7, characterized in that, The conductive layer (2) comprises, from the inside out, a copper sputtered layer (21), a copper electroplated layer (22), and a protective layer (23); wherein, the steps for forming the conductive layer (2) include: forming a copper sputtered layer (21) on the outside of the online coating layer (12) using a vacuum sputtering process; growing a copper electroplated layer (22) on the outer surface of the copper sputtered layer (21) using a water electroplating process; and forming a protective layer (23) on the outer surface of the copper electroplated layer (22) by an electroplating process.

Images