CN115732698A

CN115732698A - Composite copper foil film and preparation method thereof

Info

Publication number: CN115732698A
Application number: CN202211111592.5A
Authority: CN
Inventors: 吴培服; 吴迪; 池卫; 周振; 刘鸿纬; 赵星亮
Original assignee: Jiangsu Shuangxing Color Plastic New Materials Co Ltd
Current assignee: Jiangsu Shuangxing Color Plastic New Materials Co Ltd
Priority date: 2022-09-13
Filing date: 2022-09-13
Publication date: 2023-03-03

Abstract

The invention discloses a composite copper foil film and a preparation method thereof. The preparation method comprises the following steps: preparing a substrate layer from a polyester film added with polyester functional master batch; carrying out corona treatment on the surfaces of two sides of the base material layer to form a corona layer; forming a barrier layer on the outer side of the corona layer; the conductive layer is formed outside the barrier layer. The composite copper foil film is prepared by combining the vacuum sputtering process and the water electroplating process, and excellent electrical performance and adhesive force can be obtained on the premise of not damaging the surface structure of the base material layer.

Description

Composite copper foil film and preparation method thereof

Technical Field

The application relates to a current collector for electric conduction in a lithium ion battery, in particular to a composite copper foil film capable of being used as a negative current collector of the lithium ion battery and a preparation method thereof.

Background

The current collector in the lithium ion battery consists of a metal foil film for conducting electricity, and is mainly used for bearing electrode materials of a positive electrode and a negative electrode, and collecting current and conducting electrons at the same time. The common positive current collector adopts aluminum foil, and the common negative current collector adopts copper foil. The aluminum foil and the copper foil used as current collectors are mainly used for conduction and do not participate in active reactions, so that the thickness of the aluminum foil and the copper foil is reduced to the strength limit and no space for continuous thinning exists under the requirement of improving the energy density of the battery. By referring to the composite metal thin film in the prior art, a composite metal thin film has appeared in which a non-metallic insulating material is used as a base material and conductive layers are formed on both sides thereof.

CN 114481034A discloses a method, equipment and system for preparing composite metal foil, the equipment comprising: primary and secondary double-sided coating modules arranged at intervals; the one-time double-sided coating module comprises: the device comprises a first evaporation column, a second evaporation column, a unreeling roller, a first evaporation source, a first group of rollers, a second evaporation source and a second group of rollers, wherein the first evaporation column and the second evaporation column are oppositely arranged, and the unreeling roller, the first evaporation source, the first group of rollers, the second evaporation source and the second group of rollers are sequentially arranged on the opposite surfaces of the first evaporation column and the second evaporation column from bottom to top; the two-sided coating film module of secondary includes: the device comprises a third evaporation column, and a first group of cooling rollers, a third evaporation source, a second group of cooling rollers, a fourth evaporation source and a wind-up roller which are sequentially arranged on the third evaporation column from top to bottom. This prior art can realize once two-sided coating film through from supreme two evaporation sources of setting up and supporting roller system down on the relative surface of first and second coating by vaporization post, can realize two-sided coating film of secondary through from the top down sets gradually two evaporation sources and corresponding roller system on third coating by vaporization post, has improved place utilization and film production efficiency.

In the preparation process of the composite metal foil in the prior art, the target material needs to be evaporated into gas at high temperature and then attached to the surface of the nonmetallic substrate layer, and the higher the evaporation temperature of the target material is, the more easily the substrate layer has defects such as fusing or scalding. Therefore, the prior art generally produces composite aluminum foil by means of evaporation, and the situation that composite copper foil is prepared by evaporation is rare because the evaporation temperature of copper is higher. The higher the evaporation temperature of the target material is, the higher the running speed of the substrate layer is required to be, so that the thinner the metal layer formed by evaporation is, and the correspondingly poor conductivity of the composite metal foil is, thus being not suitable for being used as a current collector of a lithium ion battery. Therefore, the composite aluminum foil prepared by the existing evaporation can only be used as a food packaging material, and the metal layer formed by the evaporation has poor adhesive force and is very easy to fall off, so that even if the composite aluminum foil is used as the food packaging material, a protective film needs to be compounded on the surface of the metal layer to prevent the fallen metal from polluting food.

In addition, another reason why the metal layer of the aluminum laminate foil is easily peeled off is that the surface structure of the nonmetallic base material layer for receiving the metal layer is not uniform, resulting in insufficient adhesion of the metal layer to the base material layer. In order to relieve the influence of long-time high-temperature baking on the surface performance of the base material layer, the metal layers are required to be gradually stacked at intervals to form metal layers, and the defects of various structural properties of the base material layer can be gradually amplified by the stacked metal layers, so that the conventional composite metal foil and the preparation process thereof are difficult to be suitable for producing and preparing the composite copper foil film capable of being used as a current collector.

Disclosure of Invention

The technical problem to be solved by the present application is to provide a composite copper foil film and a method for preparing the same, so as to reduce or avoid the aforementioned problems.

In order to solve the technical problem, the application provides a composite copper foil film, which comprises a substrate layer and conductive layers attached to two sides of the substrate layer, wherein the conductive layers sequentially comprise a metal copper sputtering layer, a metal copper electroplating layer and a protective layer from inside to outside; the metal copper sputtering layer is a layer of metal copper with the thickness of 5-15nm formed on the two side surfaces of the base material layer by adopting a vacuum sputtering process, the metal copper electroplating layer is a layer of metal copper with the thickness of 100-500nm formed on the outer surface of the metal copper sputtering layer by adopting a water electroplating process, and the protective layer is a compact protective layer formed after the outer surface of the metal copper electroplating layer is passivated; the protective layer is a metal chromium protective layer with the thickness of 5-15nm formed by an electroplating process.

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

Preferably, a barrier layer made of 2-3nm silicon dioxide is formed on the outer side of the substrate layer between the conductive layer and the substrate layer in a sputtering mode.

Preferably, a corona layer with a thickness of 1-2nm is formed on the surface of the substrate layer, and the barrier layer is formed on the outer side of the corona layer.

Preferably, the substrate layer is made of a polyester film added with a polyester functional master batch, the polyester film is a single-layer polyester film containing 5-20 wt% of the polyester functional master batch, or a polyester film with a three-layer structure including an A layer, a B layer and a C layer, wherein the A layer and the C layer contain 5-20 wt% of the polyester functional master batch, and the polyester functional master batch is prepared from the following raw materials in parts by weight: 30-50 parts of poly (m-xylylene diamide), 1-3 parts of cobalt neodecanoate, 3-5 parts of dibutyl hydroxy toluene, 5-10 parts of 1, 4-diiodobenzene, 20-30 parts of silicon dioxide and 50-100 parts of PET.

The application further provides a preparation method of the composite copper foil film, the composite copper foil film is composed of a base material layer and conducting layers attached to two sides of the base material layer, and the preparation method comprises the following steps: preparing a substrate layer from the polyester film added with the polyester functional master batch; carrying out corona treatment on the two side surfaces of the base material layer to form corona layers; forming a barrier layer on the outer side of the corona layer; the conductive layer is formed outside the barrier layer.

Preferably, the mylar forming the substrate layer is a single-layer mylar containing 5-20 wt% of polyester functional master batch, and the mylar is prepared by the following steps: the components with the following weight ratio: 80-95 wt% of PET resin and 5-20 wt% of polyester functional master batch are respectively metered by an electronic scale and enter a mixing bin to be mixed to prepare a mixture; then the mixture enters an exhaust type double-screw extruder, and the temperature of the double-screw extruder is adjusted to 270-280 ℃; melting the materials in an extruder, filtering, and extruding to prepare a thick sheet; the thickness and the profile of the slab can be adjusted through the extrusion amount of an extruder, the rotating speed of a casting sheet roller and the opening degree of a die head; preheating the thick sheet at 50-90 ℃, feeding the thick sheet into an infrared heating zone at 300-500 ℃, and longitudinally stretching at a linear speed of 40-150 m/min, wherein the longitudinal stretching ratio is 4.0 to obtain a stretched sheet; preheating the stretching sheet at the temperature of 90-120 ℃, and transversely stretching at the temperature of 100-160 ℃, wherein the transverse stretching ratio is 3.8; then the mixture is shaped at the temperature of 160-240 ℃, and then is cooled at the temperature of 100-50 ℃ to obtain the polyester film for the composite copper foil film.

Preferably, the mylar forming the substrate layer is a mylar with a three-layer structure comprising a layer A, a layer B and a layer C, wherein the layer A and the layer C contain 5-20 wt% of polyester functional master batch, and the mylar is prepared by the following steps: the components with the following weight ratio: 80-95 wt% of PET resin and 5-20 wt% of polyester functional master batch are respectively metered by an electronic scale and enter a mixing bin to be mixed to prepare a mixture; then the mixture enters an exhaust type double-screw extruder E; putting 100% of PET resin into a pre-crystallizer, pre-crystallizing for 15 minutes at 160 ℃, then putting the PET material into a drying tower, drying for 6 hours at 160 ℃, and then putting the PET material into a single-screw extruder F; adjusting the temperature of the double-screw extruder E and F to 270-280 ℃; melting the materials in two extruders, filtering, taking the materials extruded by a double-screw extruder E as a layer A and a layer C on the surface, taking the materials extruded by a single-screw extruder F as a layer B in the middle, and preparing a three-layer composite thick sheet by a multi-layer co-extrusion process; the thickness and the profile of the slab can be adjusted through the extrusion amount of an extruder, the rotating speed of a casting sheet roller and the opening degree of a die head; preheating the thick sheet at 50-90 ℃, feeding the thick sheet into an infrared heating zone at 300-500 ℃, and longitudinally stretching at a linear speed of 40-150 m/min, wherein the longitudinal stretching ratio is 4.0 to obtain a stretched sheet; preheating the stretching sheet at the temperature of 90-120 ℃, and transversely stretching at the temperature of 100-160 ℃, wherein the transverse stretching ratio is 3.8; then shaping at 160-240 ℃, and cooling at 100-50 ℃ to obtain the three-layer polyester film.

Preferably, the preparation method further comprises the preparation step of the polyester functional masterbatch: at normal temperature, adding 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 hydroxy toluene and 5-10 parts by weight of powdered 1, 4-diiodobenzene into a high-speed mixer for pre-dispersion and mixing, wherein the rotating speed is 1500-2000 rpm, and the mixing time is 30-60 minutes to form a mixture; and then carrying out melt extrusion through a double-screw extruder, and then carrying out water-cooling granulation or slicing to obtain the polyester functional master batch.

Preferably, the conductive layer comprises a metal copper sputtering layer, a metal copper electroplating layer and a protective layer in sequence from inside to outside; wherein the forming of the conductive layer comprises: forming a metal copper sputtering layer on the outer side of the barrier layer by adopting a vacuum sputtering process; growing a metal copper electroplating layer on the outer surface of the metal copper sputtering layer by adopting a water electroplating process; and forming a protective layer on the outer surface of the metal copper electroplating layer through an electroplating process.

The polyester film forming the current collector substrate of the application is added with the polyester functional master batch, so that the formed polyester film has the characteristics of low porosity, low water absorption, low oxygen permeability and the like, the conductive layer formed on the outer side does not have obvious crack propagation, and the structural consistency of the two sides is better. The composite copper foil film is prepared by combining a vacuum sputtering process and a water electroplating process, and excellent electrical performance and adhesive force can be obtained on the premise of not damaging the surface structure of the base material layer.

Drawings

The drawings are only for purposes of illustrating and explaining the present application and are not to be construed as limiting the scope of the present application.

Fig. 1 shows a schematic structural diagram of a composite copper foil film according to an embodiment of the present application.

Fig. 2 is a schematic diagram showing a structure of a composite copper foil film according to another embodiment of the present application.

Fig. 3 is a schematic diagram illustrating a structure of a composite copper foil film according to another embodiment of the present application.

Detailed Description

In order to more clearly understand the technical features, objects, and effects of the present application, embodiments of the present application will now be described with reference to the accompanying drawings. Wherein like parts are given like reference numerals.

As shown in the figure, the invention provides a composite copper foil film capable of being used as a negative current collector of a lithium ion battery, the composite copper foil film is composed of a base material layer 1 and conducting layers 2 attached to two sides of the base material layer 1, and the conducting layers 2 are mainly composed of metal copper. As described above, since the evaporation temperature of metal copper is high, if the metal copper is attached to the surface of the base material layer 1 made of a polymer material by vapor deposition, uniformity of the surface structure of the base material layer 1 is deteriorated, and it is difficult to obtain a thickness necessary for sufficient electrical performance.

In view of the above, the present application proposes a composite copper foil film, wherein the conductive layer 2 adopts a multi-layer conductive structure, and in the illustrated embodiment, the conductive layer 2 sequentially comprises a metal copper sputtering layer 21, a metal copper electroplating layer 22 and a protective layer from inside to outside. The metal copper sputtering layer 21 is a layer of metal copper with the thickness of 5-15nm formed on the two side surfaces of the base material layer 1 by adopting a vacuum sputtering process, the metal copper electroplating layer 22 is a layer of metal copper with the thickness of 100-500nm formed on the outer surface of the metal copper sputtering layer 21 by adopting a water and electricity electroplating process, the protective layer is a compact protective layer formed by passivating the outer surface of the metal copper electroplating layer 22 by adopting an electroplating or chemical corrosion process, and preferably, the protective layer is a metal chromium protective layer 23 with the thickness of 5-15nm formed by adopting an electroplating process. More preferably, the thickness of the metal copper sputtering layer 21 is 5-8nm, the thickness of the metal copper electroplating layer 22 is 300-400nm, and the thickness of the metal chromium protective layer 23 is 5-8nm.

In the composite copper foil film, the compactness and the adhesive force of a metal copper sputtering layer formed by vacuum sputtering are far superior to those of an evaporation process, and the running speed of the base material layer can be fast due to the fact that the required thickness is very thin, so that the possibility that the base material layer has the defects of fusing or scalding and the like is basically avoided. The thickness of the metal copper sputtering layer is very thin, but basic conductive performance can be provided, so that a thicker metal copper layer can be further grown on the surface of the metal copper sputtering layer by means of water electroplating. Through the combination of the vacuum sputtering process and the water electroplating process, the application can obtain excellent electrical performance and adhesive force on the premise of not damaging the surface structure of the base material layer, which will be further explained later.

In addition, in order to avoid the problem of insufficient adhesion of a metal copper layer caused by non-uniform surface structure of the substrate layer, the present application also provides an improved substrate layer 1, in a specific embodiment of the present application, the substrate layer 1 of the present application is made of a polyester film added with a polyester functional masterbatch, and the substrate layer 1 may be a single-layer structure polyester film (fig. 1) added with the polyester functional masterbatch, or a three-layer structure polyester film (fig. 2) including an a layer, a B layer and a C layer, to which the polyester functional masterbatch is added on the surface layer.

The polyester referred to in the present invention means a polyester formed from one or more species selected from among polycarboxylic acids containing dibasic acids and their ester-forming derivatives, and one or more species selected from among polyhydric alcohols containing dihydric alcohols; or polyesters formed from hydroxycarboxylic acids and their ester-forming derivatives; or a polyester formed from a cyclic ester. The polyester can be produced by a conventionally known method. For example, taking the preparation of PET as an example, it can be obtained by: a method of performing polycondensation after esterification of terephthalic acid and ethylene glycol; or a method in which an alkyl ester of terephthalic acid such as dimethyl terephthalate is subjected to a transesterification reaction with ethylene glycol and then subjected to polycondensation. The polyester of the present invention is preferably PET.

In a specific embodiment, the polyester film forming the substrate layer 1 is a single-layer polyester film containing 5 to 20wt% of polyester functional master batch, or is a three-layer polyester film containing an a layer, a B layer and a C layer, wherein the a layer and the C layer contain 5 to 20wt% of polyester functional master batch, and the polyester functional master batch is prepared from the following raw materials in parts by weight: 30-50 parts of poly (m-xylylene diamide), 1-3 parts of cobalt neodecanoate, 3-5 parts of dibutyl hydroxy toluene, 5-10 parts of 1, 4-diiodobenzene, 20-30 parts of silicon dioxide and 50-100 parts of PET.

The polyester functional master batch of the present invention can be prepared in a pellet or chip form, and added to a common polyester in the process of producing a polyester film to prepare the substrate layer 1 of the present invention. For example, 80 to 95wt% of polyester without other components and 5 to 20wt% of the polyester functional masterbatch of the present invention may be melt-blended, and then the substrate layer 1 of a single-layer structure may be produced by a process such as stretching, or the surface layer structure of the substrate layer 1 of the present invention may be obtained by a multilayer co-extrusion process.

The raw material components of the polyester functional master batch can be uniformly mixed in the form of granules, and then the polyester functional master batch can be obtained by extrusion and granulation by using equipment such as an extruder.

In one embodiment, 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 (m-xylylene diamide), 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 into a high-speed mixer for pre-dispersion and mixing, and the rotation speed is 1500-2000 rpm and the mixing time is 30-60 minutes to form a mixture. And then carrying out melt extrusion through a double-screw extruder, and then carrying out water-cooling granulation or slicing to obtain the polyester functional master batch.

In another embodiment, for example, after preparing the chip for obtaining the polyester functional master batch, 5 to 20wt% of the polyester functional master batch is added to 80 to 95wt% of PET particles for uniform mixing, the two are melt blended, and finally the substrate layer 1 with a single-layer structure is obtained through a process such as stretching, or the surface layer structure of the substrate layer 1 with a three-layer structure is obtained through a multilayer co-extrusion process.

The preparation method of the polyester film for the composite copper foil film of the present invention is further described below by taking a single-layer polyester film as an example. The preparation method of the polyester film for the composite copper foil film comprises the following steps:

the components with the following weight ratio: 80-95 wt% of PET resin and 5-20 wt% of polyester functional master batch are respectively metered by an electronic scale and enter a mixing bunker to be mixed to prepare a mixture.

Then the mixture enters an exhaust type double-screw extruder, and the temperature of the double-screw extruder is adjusted to be 270-280 ℃.

After the materials are melted in an extruder, the materials are filtered and extruded to be made into thick sheets. The thickness and the profile of the slab can be adjusted by the extrusion amount of an extruder, the rotating speed of a casting sheet roller and the opening degree of a die head.

Preheating the thick sheet at 50-90 ℃, entering an infrared heating zone at 300-500 ℃, and longitudinally stretching at a linear speed of 40-150 m/min, wherein the longitudinal stretching ratio is 4.0, thus obtaining the stretched sheet.

Preheating the stretched sheet at the temperature of 90-120 ℃, and transversely stretching the sheet at the temperature of 100-160 ℃, wherein the transverse stretching ratio is 3.8. Then the mixture is shaped at the temperature of 160-240 ℃, and then is cooled at the temperature of 100-50 ℃ to prepare the polyester film for the composite copper foil film.

The thickness of the polyester film is 6-10 μm.

The preparation method of the polyester film for the composite copper foil film of the present invention is further described below by taking a three-layer polyester film as an example. The preparation method of the polyester film for the composite copper foil film comprises the following steps:

And then the mixture enters an exhaust type double-screw extruder E.

100% of PET resin is put into a pre-crystallizer, pre-crystallized for 15 minutes at the temperature of 160 ℃, and then the PET material enters a drying tower, is dried for 6 hours at the temperature of 160 ℃ and then enters a single-screw extruder F.

The temperature of the twin-screw extruder E and the twin-screw extruder F is adjusted to 270 ℃ to 280 ℃.

After materials are melted in two extruders, the materials extruded by a double-screw extruder E are used as a layer A and a layer C on the surface, the materials extruded by a single-screw extruder F are used as a layer B in the middle, and a three-layer composite thick sheet is prepared by a multilayer co-extrusion process. The thickness and the profile of the thick sheet can be adjusted by the extrusion amount of the extruder, the rotating speed of the sheet casting roller and the opening degree of the die head.

Preheating the stretching sheet at the temperature of 90-120 ℃, and transversely stretching the stretching sheet at the temperature of 100-160 ℃, wherein the transverse stretching ratio is 3.8. Then the three-layer structure polyester film is prepared by shaping at the temperature of 160-240 ℃ and cooling at the temperature of 100-50 ℃.

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

Examples 1 to 5

According to the weight parts of the raw materials in the following table, polyester functional master batch chips are respectively prepared and then added with common PET resin to prepare the polyester film with a single-layer structure for the composite copper foil film.

	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
						Dibutylhydroxytoluene	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 prepare a monolayer substrate layer	5wt％	10wt％	13wt％	15wt％	20wt％
Thickness of the substrate layer	6	7	8	9	10

Comparative examples 6 to 10

In the same manner as in the above examples, comparative polyester films were prepared in the following raw material weight ratio.

	Comparative example 6	Comparative example 7	Comparative example 8	Comparative example 9	Comparative example 10
						Poly (m-xylylene diamide)	0	35	40	45	50
Cobalt neodecanoate	1	0	2	2.5	3
						Dibutylhydroxytoluene	3	3.5	0	4.5	5
1, 4-diiodobenzene	5	7	7.5	0	10
						Silicon dioxide	20	22	25	27	0
PET	80	66.5	79	93	130
						Amount of slices to prepare a monolayer substrate layer	5wt％	10wt％	13wt％	15wt％	20wt％
Thickness of the substrate layer	6	7	8	9	10

The performance parameters of each polyester film were obtained by testing and preparing respectively, and the films with thickness of 8 μm prepared from pure PET without any functional master batch were compared, and the performance parameters are shown in the following table.

And respectively forming metal copper sputtering layers on the surfaces of the two sides of the polyester film on the upper surface by a vacuum sputtering process, controlling the thickness of the metal copper layers on the two sides of the vacuum sputtering film to be 5nm, and testing the surface crack parameters of the prepared film.

The performance parameters of the film layer and the crack condition of the metal coating are seen, the porosity, the water absorption rate, the oxygen transmission rate and other performances of the polyester film prepared by adding the polyester functional master batch are greatly improved, and no obvious crack expansion is seen after the metal copper conducting layer is formed.

Further, the resistivity difference of the metal copper sputtered layers on both sides of the polyester film shown in the above table was tested as shown in the following table.

According to the polyester film prepared by adding the polyester functional master batch, the resistivity difference of a metal copper sputtering layer formed on the polyester film is obviously smaller than that of a film without the functional master batch, and the two-side structure of the film is more excellent in consistency.

Further, since the present application requires that the metal copper sputtering layer 21 is formed on the surface of the base material layer 1 first, the base material layer 1 needs to be controlled to operate at a low temperature during sputtering. Although the mylar of the improved substrate layer 1 has excellent properties such as porosity, water absorption, oxygen transmission rate, etc., it is still necessary to prevent the interference of the moisture released when the mylar surface absorbs water at low temperature and then sputters with the vacuum degree.

Therefore, in a specific embodiment, in order to avoid the moisture absorption and release problem of the substrate layer 1 during sputtering, a barrier layer 11 is further formed on the outer side of the substrate layer 1 between the conductive layer 2 and the substrate layer 1 by sputtering to improve the performance of the conductive layer 2, as shown in fig. 3. Specifically, a layer of barrier layer 11 made of 2-3nm silicon dioxide can be deposited on each of the two side surfaces of the substrate layer 1 through a double-rotating cathode and intermediate frequency reactive magnetron sputtering method, so that the surface of the substrate layer 1 is coated and isolated, and a hydrophobic structure is formed on the surface of the substrate layer 1.

Further, since the thickness of the barrier layer 11 is small, in order to improve the adhesion of the barrier layer 11 to the surface of the base material layer 1, it is preferable that the surface of the base material layer 1 is subjected to corona treatment before the formation of the barrier layer 11 by sputtering so as to form a corona layer 10 having a thickness of 1 to 2nm on the surface of the base material layer 1, and the barrier layer 11 is formed outside the corona layer 10. The corona treatment is a prior art, and the basic principle is that corona discharge is carried out on the surface of the treated plastic by using high frequency and high voltage to roughen the surface of the substrate layer 1 so as to increase the adhesion capability of the surface of the substrate layer 1 to the barrier layer 11.

The following further describes a method for producing the composite copper foil film of the present application.

As described above, the composite copper foil film of the present application is composed of the substrate layer and the conductive layers attached to both sides of the substrate layer, and thus, the method for preparing the composite copper foil film of the present application includes the steps of: firstly, a substrate layer is made of a polyester film added with polyester functional master batch. The process steps for preparing the substrate layer have been described in detail above and will not be repeated here.

Then carrying out corona treatment on the surfaces of the two sides of the base material layer to form a corona layer; then forming a barrier layer on the outer side of the corona layer; and finally, forming the conductive layer on the outer side of the barrier layer.

Further, as described above, the conductive layer includes a metal copper sputtering layer, a metal copper electroplating layer, and a protective layer in this order from the inside to the outside. Therefore, the step of forming the conductive layer includes: forming a metal copper sputtering layer on the outer side of the barrier layer by adopting a vacuum sputtering process; growing a metal copper electroplating layer on the outer surface of the metal copper sputtering layer by adopting a water electroplating process; and forming a protective layer on the outer surface of the metal copper electroplating layer through an electroplating process.

The polyester films prepared in examples 1 to 5 were used as a base material layer, and were 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 prepare a composite copper foil film having the following parameters.

According to the measurement parameters, the composite copper foil film has excellent electrical performance, the adhesive force of the conducting layer is extremely strong, and the conducting layer can hardly be peeled off in conventional use.

It should be appreciated by those skilled in the art that while the present application is described in terms of several embodiments, not every embodiment includes only a single embodiment. Such descriptions are merely for clarity reasons and should be understood by those skilled in the art as a whole and the technical solutions involved in the embodiments should be considered as being combinable with each other into different embodiments to understand the scope of the present application.

The above description is only illustrative of the present invention and is not intended to limit the scope of the present invention. Any equivalent changes, modifications and combinations that may be made by those skilled in the art without departing from the spirit and principles of the present application shall fall within the scope of the present application.

Claims

1. The composite copper foil film is composed of a base material layer and conducting layers attached to two sides of the base material layer, and is characterized in that the conducting layers sequentially comprise a metal copper sputtering layer, a metal copper electroplating layer and a protective layer from inside to outside; the metal copper sputtering layer is formed on the two side surfaces of the base material layer by adopting a vacuum sputtering process, the thickness of the metal copper sputtering layer is 5-15nm, the metal copper electroplating layer is a layer of 100-500nm metal copper formed on the outer surface of the metal copper sputtering layer by adopting a water electroplating process, and the protective layer is a compact protective layer formed by passivating the outer surface of the metal copper electroplating layer; the protective layer is a metal chromium protective layer with the thickness of 5-15nm formed by an electroplating process.

2. The composite copper foil film according to claim 1, wherein the thickness of the sputtered layer of metal copper is 5 to 8nm, the thickness of the electroplated layer of metal copper is 300 to 400nm, and the thickness of the protective layer of metal chromium is 5 to 8nm.

3. The composite copper foil film according to claim 1, wherein a barrier layer made of 2-3nm silica is formed on the outer side of the substrate layer between the conductive layer and the substrate layer by sputtering.

4. The composite copper foil film according to claim 3, wherein a corona layer having a thickness of 1 to 2nm is formed on the surface of the base material layer, and the barrier layer is formed outside the corona layer.

5. The composite copper foil film according to claim 1, wherein the substrate layer is made of a polyester film added with a polyester functional masterbatch, the polyester film is a single-layer polyester film containing 5-20 wt% of the polyester functional masterbatch, or a polyester film with a three-layer structure comprising an A layer, a B layer and a C layer, wherein the A layer and the C layer contain 5-20 wt% of the polyester functional masterbatch, and the polyester film comprises the following raw materials in parts by weight: 30-50 parts of poly (m-xylylene diamide), 1-3 parts of cobalt neodecanoate, 3-5 parts of dibutyl hydroxy toluene, 5-10 parts of 1, 4-diiodobenzene, 20-30 parts of silicon dioxide and 50-100 parts of PET.

6. A preparation method of a composite copper foil film, wherein the composite copper foil film is composed of a base material layer and conducting layers attached to two sides of the base material layer, and the preparation method comprises the following steps: preparing a substrate layer from a polyester film added with polyester functional master batch; carrying out corona treatment on the surfaces of two sides of the base material layer to form a corona layer; forming a barrier layer on the outer side of the corona layer; and forming the conductive layer on the outer side of the barrier layer.

7. The method of claim 6, wherein the mylar constituting the substrate layer is a single-layer mylar containing 5 to 20wt% of a polyester functional master batch, and the mylar is prepared by:

the components with the following weight ratio: 80-95 wt% of PET resin and 5-20 wt% of polyester functional master batch are respectively metered by an electronic scale and enter a mixing bunker to be mixed to prepare a mixture;

then the mixture enters an exhaust type double-screw extruder, and the temperature of the double-screw extruder is adjusted to 270-280 ℃;

melting the materials in an extruder, filtering, and extruding to prepare a thick sheet; the thickness and the profile of the slab can be adjusted through the extrusion amount of an extruder, the rotating speed of a casting sheet roller and the opening degree of a die head;

preheating the thick sheet at 50-90 ℃, feeding the thick sheet into an infrared heating zone at 300-500 ℃, and longitudinally stretching at a linear speed of 40-150 m/min, wherein the longitudinal stretching ratio is 4.0 to obtain a stretched sheet;

preheating the stretching sheet at the temperature of 90-120 ℃, and transversely stretching at the temperature of 100-160 ℃, wherein the transverse stretching ratio is 3.8; then the mixture is shaped at the temperature of 160-240 ℃, and then is cooled at the temperature of 100-50 ℃ to prepare the polyester film for the composite copper foil film.

8. The method of claim 6, wherein the mylar constituting the substrate layer is a mylar having a three-layer structure comprising a layer a, a layer B and a layer C containing 5 to 20wt% of a functional polyester masterbatch, the mylar being prepared by:

the components with the following weight ratio: 80-95 wt% of PET resin and 5-20 wt% of polyester functional master batch are respectively metered by an electronic scale and enter a mixing bin to be mixed to prepare a mixture;

then the mixture enters an exhaust type double-screw extruder E;

putting 100% of PET resin into a pre-crystallizer, pre-crystallizing for 15 minutes at 160 ℃, then putting the PET material into a drying tower, drying for 6 hours at 160 ℃, and then putting the PET material into a single-screw extruder F;

adjusting the temperature of the double-screw extruder E and the double-screw extruder F to 270-280 ℃;

melting the materials in two extruders, filtering, taking the materials extruded by a double-screw extruder E as a layer A and a layer C on the surface, taking the materials extruded by a single-screw extruder F as a layer B in the middle, and preparing a three-layer composite thick sheet by a multi-layer co-extrusion process; the thickness and the profile of the thick sheet can be adjusted through the extrusion amount of an extruder, the rotating speed of a sheet casting roller and the opening degree of a die head;

preheating the stretching sheet at the temperature of 90-120 ℃, and transversely stretching at the temperature of 100-160 ℃, wherein the transverse stretching ratio is 3.8; then shaping at 160-240 ℃, and cooling at 100-50 ℃ to obtain the three-layer polyester film.

9. The production method according to claim 7 or 8, further comprising a production step of the polyester functional masterbatch: at normal temperature, adding 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 hydroxy toluene and 5-10 parts by weight of powdered 1, 4-diiodobenzene into a high-speed mixer for pre-dispersion and mixing, wherein the rotating speed is 1500-2000 rpm, and the mixing time is 30-60 minutes to form a mixture; and then carrying out melt extrusion through a double-screw extruder, and then carrying out water-cooling granulation or slicing to obtain the polyester functional master batch.

10. The production method according to claim 6, wherein the conductive layer comprises, in order from the inside to the outside, a sputtered layer of metal copper, an electroplated layer of metal copper, and a protective layer; wherein the forming of the conductive layer comprises: forming a metal copper sputtering layer on the outer side of the barrier layer by adopting a vacuum sputtering process; growing a metal copper electroplating layer on the outer surface of the metal copper sputtering layer by adopting a water electroplating process; and forming a protective layer on the outer surface of the metal copper electroplating layer through an electroplating process.