Copper-plated graphene film, graphene / copper composite material and preparation method of graphene / copper composite material

Abstract

The invention provides a copper-plated graphene film, a graphene / copper composite material and a preparation method of the graphene / copper composite material. The preparation method of the copper-plated graphene film comprises the following steps: carrying out surface pretreatment on a graphene film to form an adsorption film on the surface of the graphene film to obtain an intermediate material; a copper layer is formed on the surface, with the adsorption film, of the intermediate material through an electroplating method, and a copper-plated graphene film is obtained; the adsorption film is formed by combining a pretreatment agent on the surface of the graphene film in at least one form of physical adsorption, chemical adsorption or electrostatic adsorption, and the pretreatment agent comprises at least one of an acid compound, a silane coupling agent or an ionic surfactant. The graphene / copper composite material is prepared by hot pressing and sintering a copper-plated graphene film. An adsorption film is formed on a graphene film to improve the wettability and chemical activity of the surface of the graphene film, the binding force between the graphene film and a copper layer is enhanced, and the copper layer is prevented from falling off and cracking; and the pretreatment film is also beneficial to uniform distribution of a copper plating solution on the surface of the graphene, so that the uniformity of a copper layer is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of graphene composite materials, and in particular relates to a copper-plated graphene film, a graphene / copper composite material and a preparation method thereof. Background Art

[0002] The continuous miniaturization demand of semiconductor devices and the pursuit of high performance of semiconductor devices have posed great challenges to thermal management materials. Solving the heat dissipation problem of semiconductor devices urgently requires the development of thermal conductive materials with excellent performance. For example, the radio frequency block center (RBC) heat sink fins used in high-speed railways are required to have excellent comprehensive performance, usually requiring their thermal conductivity (TC) to be greater than 800W / m·K, thermal expansion coefficient (CTE) to be less than 10ppm / K, and excellent mechanical properties. Faced with such harsh conditions, carbon-reinforced metal-based composites with high TC and adjustable CTE are one of the ideal choices to meet thermal conductivity requirements in the future. Copper, as a traditional thermal management material, has a high TC and is a potential matrix material. Graphene has become one of the most promising materials in the field of advanced composite materials due to its excellent thermal and electrical properties. Therefore, the combination of graphene and copper is regarded as a good choice for thermal management applications, and thus the composite material of graphene and copper has become the focus of research.

[0003] However, there are still some problems in the current method of preparing graphene / copper composite materials. For example, the prior art CN118756123A provides a method for preparing highly conductive graphene copper composite materials by chemical plating, which uses graphene-coated copper foil as raw material, and deposits a layer of copper on the surface of the graphene-coated copper foil by chemical plating method to generate copper-plated graphene-coated copper foil. Then, the copper-plated graphene-coated copper foil is stacked in multiple layers, and the multi-layer copper-plated graphene-coated copper foil is hot-pressed by hot pressing process to obtain highly conductive graphene copper composite materials. The preparation of graphene copper composite materials based on chemical plating method has some obvious disadvantages, such as chemical plating must control the reaction speed, can not be too fast, otherwise it will produce various coating defects. Compared with electroplating, chemical plating has a complex solution composition and poor stability, and the maintenance, adjustment of pH and regeneration of the solution are more troublesome, and the material cost is higher. The working temperature of many chemical platings is around 90 ° C, and maintaining this temperature also consumes a lot of energy.

[0004] In addition, due to the large difference in surface free energy between graphene and copper, graphene and copper are not easy to combine, which will affect the performance of graphene-copper composite materials. Summary of the invention

[0005] In order to solve all or part of the above technical problems, the present invention provides the following technical solutions:

[0006] One of the purposes of the present invention is to provide a method for preparing a copper-plated graphene film, comprising:

[0007] Performing surface pretreatment on the graphene film to form an adsorption film on the surface of the graphene film to obtain an intermediate material;

[0008] Forming a copper layer on the surface of the intermediate material having the adsorption film by electroplating to obtain a copper-plated graphene film;

[0009] The adsorption film is formed by a pretreatment agent being bonded to the surface of the graphene film in the form of at least one of physical adsorption, chemical adsorption or electrostatic adsorption, and the pretreatment agent includes one or more combinations of acid compounds, silane coupling agents or ionic surfactants.

[0010] Due to the large difference in surface free energy between graphene and copper, it is difficult for graphene to combine with copper, and graphene itself is easy to agglomerate, which leads to poor performance of the composite material obtained by directly copper plating on the graphene surface. The present invention forms an adsorption film on the graphene film through surface pretreatment, which can improve the wettability and chemical activity of the graphene film surface, making it easier to react with the copper plating solution. Electroplating copper on the basis of the pretreatment film can enhance the bonding force between graphene and the copper plating layer, and prevent the electroplated copper layer from falling off and cracking; and the pretreatment film also helps the copper plating solution to be evenly distributed on the graphene surface, improving the uniformity and consistency of the copper layer.

[0011] In some embodiments, the surface pretreatment specifically includes:

[0012] Providing a pretreatment solution, wherein the pretreatment solution comprises a pretreatment agent at a concentration of 20 to 50 wt %;

[0013] The temperature of the pretreatment liquid is adjusted to 30-60° C., and the graphene film is immersed in the pretreatment liquid and maintained for 2-120 minutes to form the adsorption film on the surface of the graphene film.

[0014] In some embodiments, when the pretreatment agent is an acid compound, the graphene film is immersed in the pretreatment solution for 2 to 5 minutes; when the pretreatment agent is a silane coupling agent and / or an ionic surfactant, the graphene film is immersed in the pretreatment solution for 30 to 120 minutes.

[0015] In some embodiments, the acid compound includes one or more of sulfuric acid, hydrochloric acid, hydrofluoric acid or acetic acid. These acid compounds can form the adsorption film on the surface of the graphene film in the form of physical adsorption based on intermolecular van der Waals force.

[0016] In some embodiments, the pretreatment agent is a silane coupling agent that can form an adsorption film on the graphene surface in the form of chemical adsorption, and the silane coupling agent includes KH550 and / or KH560. These silane coupling agents can be combined with the graphene film surface by surface chemical adsorption, and the adsorption film formed by chemical adsorption is more solid than that by physical adsorption.

[0017] In some embodiments, the ionic surfactant includes sodium lauryl sulfate and / or sodium dodecyl sulfate. These ionic surfactants can form an adsorption film on the surface of the graphene film in the form of electrostatic adsorption.

[0018] Among the above-mentioned pretreatment agents, acid compound pretreatment agents are more suitable for cleaning and removing oxide layers, ionic surfactants are more suitable for improving the uniformity and adhesion of electroplated copper layers, and silane coupling agents can improve the stability and durability of electroplated copper layers.

[0019] In some embodiments, the electroplating method specifically includes: using the intermediate material as a cathode, placing it together with an anode in an electroplating solution for copper plating, wherein the electroplating solution includes 10 to 50 g / L of copper salt and 30 to 70 g / L of a complexing agent, the pH value of the electroplating solution is 4 to 5, and the electroplating current density is 1 to 3 A / dm- 2 .

[0020] In some embodiments, the electroplating solution further includes a brightener for improving the glossiness of the copper layer. The brightener can be any brightener known in the art, and the present invention is not particularly limited thereto. The use, concentration, dosage, etc. of the brightener can be added according to the brand of the brightener used and the manufacturer's recommendations.

[0021] In some embodiments, the anode is phosphor copper.

[0022] In some embodiments, the electroplating time is 20 to 30 minutes.

[0023] In some embodiments, the copper layer has a thickness of 20-40 μm.

[0024] In some embodiments, the method further comprises the step of cleaning the graphene film before the surface pretreatment to remove oil and impurities on the surface of the graphene film. After cleaning, the graphene film can be rinsed with deionized water and placed in a vacuum drying oven at 60-70° C. before the surface pretreatment is performed.

[0025] The solvent used for the cleaning may include one or more combinations of deionized water, ethanol, acetone, isopropanol, and ethyl acetate, and the cleaning solvent may be selected according to actual conditions. For example, ethanol can remove some water-insoluble organic matter, such as fats and certain coatings, and also has a certain cleaning effect on some water-soluble impurities. Acetone can effectively remove a variety of organic pollutants, including grease, wax, and some polymer residues. Isopropanol has a strong ability to remove organic pollutants, especially fats and oils. Compared with acetone, isopropanol is relatively mild. Ethyl acetate is suitable for removing certain organic pollutants, especially resins, greases, etc.; its polarity is between polar and non-polar solvents, and it can handle a wide range of pollutants. In addition, ultrasonic cleaning can also be used to further improve the cleaning effect.

[0026] The second object of the present invention is to provide a copper-plated graphene film, which is prepared by any of the methods described above. In the prepared copper-plated graphene film, the graphene film and the copper layer have good bonding force, and the copper-plated layer is not easy to fall off and is evenly distributed. The copper-plated graphene film has good thermal conductivity, corrosion resistance and mechanical properties.

[0027] A third object of the present invention is to provide a method for preparing a graphene / copper composite material, comprising:

[0028] A copper-plated graphene film is prepared by any of the above methods;

[0029] A plurality of the copper-plated graphene films are stacked to form a stacked structure, and the stacked structure is subjected to a hot pressing and sintering process to form the graphene / copper composite material.

[0030] In some embodiments, at least two adjacent copper-plated graphene films in the stacked structure are bonded by a metal composite adhesive, and the metal composite adhesive comprises, by weight:

[0031] Polymer resin particles: 50-60 parts;

[0032] Metal filler: 10-30 parts;

[0033] Toughening agent: 1-10 parts;

[0034] Coupling agent: 0.1-1 part;

[0035] Curing agent: 0.1-0.2 parts;

[0036] Organic solvent: 5 to 35 parts.

[0037] Conventional adhesives have poor thermal conductivity and will increase interfacial thermal resistance. The present invention adds metal powder with high thermal conductivity to the adhesive, which can effectively improve the thermal conductivity of the adhesive, thereby increasing the thermal conductivity between the graphene film and the copper plating, and between adjacent copper-plated graphene films. In addition, the metal has better high temperature resistance. In high temperature and harsh environment, the high temperature resistance of metal thermal conductive adhesive is better than that of ordinary adhesives. In addition, the viscosity of ordinary adhesives may decrease under excessively high temperature conditions, while the addition of metal improves the overall temperature resistance of the adhesive, thereby ensuring that the adhesive still has good adhesion and making the adhesive more stable.

[0038] The metal composite adhesive also has good permeability. During the hot pressing sintering process, the metal composite adhesive can penetrate into the microscopic space between the graphene and the copper-plated layer and fill the gaps at the interface, which helps to form a closer contact. After the metal composite adhesive is cured, its thermal expansion coefficient can better match that of the graphene and the copper-plated layer, reducing the interface stress caused by temperature changes and reducing the risk of interface peeling.

[0039] In some embodiments, the resin raw material of the polymer resin particles includes one or a combination of epoxy resin, polyurethane or acrylate.

[0040] In some embodiments, the metal filler is metal powder, including copper powder and / or silver powder. The particle size of the metal powder is 10-100 μm.

[0041] In some embodiments, the organic solvent includes one or more of acetone, butanone, N,N-dimethylformamide or dichloromethane.

[0042] In some embodiments, the toughening agent includes a combination of one or more of liquid polysulfide rubber, liquid carboxyl-terminated polybutadiene rubber, liquid hydroxyl-terminated polybutadiene rubber, or polyvinyl acetal.

[0043] In some embodiments, the coupling agent includes KH-550 and / or KH-560.

[0044] In some embodiments, the curing agent includes methyltetrahydrophthalic anhydride.

[0045] In some embodiments, the preparation method also includes: before the hot pressing and sintering treatment, the stacked structure is subjected to multi-stage step-by-step heating, and then the temperature is raised to the sintering temperature to perform the hot pressing and sintering treatment; wherein the multi-stage step-by-step heating includes: firstly raising the temperature to 70-80°C at a heating rate of 3-5°C / min and keeping it warm for 1-2 hours, then raising the temperature to 90-110°C at a heating rate of 3-5°C / min and keeping it warm for 1-2 hours, and then raising the temperature to 120-140°C at a heating rate of 3-5°C / min and keeping it warm for 1-2 hours.

[0046] Multi-stage step heating can control the rate of chemical reaction or physical change of metal composite adhesive, avoiding adverse reaction or material damage of metal composite adhesive caused by too fast heating. It is also beneficial to reduce stress and optimize the pyrolysis process and product distribution.

[0047] In the above-mentioned multi-stage step-by-step heating process, within the temperature range of 70-90°C, the metal composite adhesive first becomes more fluid, fully penetrates into the tiny gaps of the copper-plated graphene film, increases the contact area between the graphene and the copper layer, and between two adjacent copper-plated graphene films, and thus enhances the adhesion; within the temperature range of 90-140°C, the metal composite adhesive undergoes thermal curing, making it more stable and forming a strong bonding layer. The high temperature in the subsequent hot pressing sintering stage can promote the evaporation and diffusion of the metal composite adhesive, forming a better interface layer and improving the interconnectivity between the graphene and the copper-plated layer.

[0048] The polyurethane in the metal composite adhesive based on polyurethane resin particles undergoes a cross-linking reaction under high temperature conditions to form a dense network structure, which enhances its mechanical strength. The metal composite adhesive based on acrylate resin particles can form a cross-linking structure when thermally cured under high temperature conditions, improving its temperature resistance and chemical resistance. The metal composite adhesive based on epoxy resin particles can effectively enhance its bonding performance and mechanical strength when cured under high temperature conditions. The cured epoxy resin exhibits good heat resistance and chemical stability, and forms a solid three-dimensional network structure that is not easily deformed.

[0049] In some embodiments, the hot pressing sintering process includes: first heating the temperature to 400-450°C at a heating rate of 2.5-3°C / min and keeping it warm for 30-60 minutes, then heating the temperature to 750-850°C at a heating rate of 5-10°C / min and keeping it warm for 60-90 minutes; the sintering pressure of the hot pressing sintering process is 20-30MPa.

[0050] The above hot pressing and sintering process can obtain a graphene / copper composite material with good thermal conductivity and mechanical strength to meet the application requirements in the fields of electronic packaging and thermal management. The one-time hot pressing process can not only achieve the adhesion of the copper-plated graphene film and the metal composite adhesive and optimize the performance of the overall material, but also improve production efficiency due to its simple process.

[0051] A fourth object of the present invention is to provide a graphene / copper composite material, which is prepared by any of the methods described above.

[0052] Compared with the prior art, the present invention has at least the following beneficial effects:

[0053] (1) The present invention forms an adsorption film on the graphene film through surface pretreatment, thereby improving the wettability and chemical activity of the graphene film surface, making it easier to react with the electroplating copper solution. Electroplating on the basis of the pretreated film can enhance the bonding force between the graphene and the copper-plated layer, and prevent the electroplated copper layer from falling off and cracking; and the pretreated film also helps the copper-plated solution to be evenly distributed on the graphene surface, thereby improving the uniformity and consistency of the copper layer.

[0054] (2) The metal composite adhesive used in the present invention has good thermal conductivity and temperature resistance, and maintains good adhesion under high temperature conditions. The use of the metal composite adhesive to bond the copper-plated graphene film and combined with hot pressing treatment can improve the interface bonding strength between the graphene and the copper-plated layer, ensuring that the laminated structure is not easy to fall off or damaged when subjected to external forces; and can improve the thermal conductivity of the prepared graphene / copper composite material, as well as its tolerance to harsh environments such as high temperature and high humidity, thereby broadening its application range.

[0055] (3) The copper-plated graphene film prepared by the present invention has good thermal conductivity (up to 8-11.6 ppm K- 1 ), thermal expansion coefficient (up to 600±50W / mk in some solutions), corrosion resistance and mechanical properties; the graphene / copper composite material formed by hot pressing has good mechanical strength and thermal conductivity; and compared with pure copper, the copper-plated graphene film and graphene / copper composite material show excellent heat dissipation ability in cooling. The prepared copper-plated graphene film and graphene / copper composite material are suitable for use in electronic packaging, thermal management and other fields, such as flexible electronic devices and wearable devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0057] Figure 1 is the thermal expansion coefficient of the copper-plated graphene film in Example 1 of the present invention.

[0058] Figure 2 is the thermal expansion coefficient of the copper-plated graphene film in Example 2 of the present invention.

[0059] Figure 3 is the thermal expansion coefficient of the copper-plated graphene film in Example 3 of the present invention. DETAILED DESCRIPTION

[0060] The technical solution of the present invention is described in detail below in conjunction with specific embodiments so that those skilled in the art can better understand and implement the technical solution of the present invention. The specific functional details disclosed herein should not be interpreted as limiting, but only as the basis for the claims and as a representative basis for teaching those skilled in the art to adopt the present invention in different ways in any appropriate detailed embodiment.

[0061] In addition, unless otherwise specified, the various raw materials used in the following examples can be purchased from the market, etc., the various production and testing equipment used are also equipment known in the art, and the testing methods used are commonly used testing methods in the art. Unless otherwise specified, the "parts" described in the specific implementation mode are parts by mass.

[0062] Example 1

[0063] This embodiment provides a copper-plated graphene film and a preparation method thereof, and the prepared copper-plated graphene film is used to further prepare a graphene / copper composite material.

[0064] The preparation method of the copper-plated graphene film specifically comprises the following steps:

[0065] (1) Take a graphene film with a thickness of 70 μm, put the graphene film into the cleaning tank of an ultrasonic cleaner, add 20 ml of ethanol, set the cleaning time to 15 minutes, the temperature to room temperature, and turn on the ultrasonic cleaner for cleaning; after cleaning, rinse the graphene film with deionized water to remove residual cleaning solvent and impurities; and place the cleaned graphene film in a vacuum drying oven at 60°C for drying.

[0066] (2) performing surface pretreatment on the cleaned graphene film: preparing a pretreatment solution with hydrofluoric acid, wherein the concentration of hydrofluoric acid in the pretreatment solution is 20 wt %; heating the temperature of the pretreatment solution to 60° C., and immersing the graphene film in the pretreatment solution for 3 min to form an adsorption film on the surface of the graphene film; after completion, taking out the graphene film and washing it with deionized water to obtain a graphene film with an adsorption film.

[0067] (3) The graphene film with adsorption film prepared as above was used as cathode for electroplating treatment, and phosphorus-containing copper plate was used as anode. The electroplating solution included 30 g / L CuSO4·5H2O and 50 g / L NaKC4H4O6 complexing agent, and sulfuric acid was added to adjust the pH value of the electroplating solution to 4.5; the current density was set to 2 A / dm- 2 Electroplating was performed for 25 min to form a copper layer with a thickness of 25 μm on both sides of the graphene film to obtain a copper-plated graphene film.

[0068] This embodiment also uses a hot pressing sintering process to make the copper-plated graphene film into a graphene / copper composite material, which specifically includes the following steps:

[0069] S1: Prepare a metal composite adhesive. The metal composite adhesive of this embodiment includes, by weight:

[0070] Acetone: 19.4 parts;

[0071] Polyurethane resin particles: 55 parts;

[0072] Polyvinyl acetal: 5 parts;

[0073] Copper powder: 20 parts, particle size 50 μm;

[0074] KH550: 0.5 parts;

[0075] Methyltetrahydrophthalic anhydride: 0.1 parts.

[0076] S2: stacking the 100 copper-plated graphene films prepared above, and bonding the adjacent copper-plated graphene films with the metal composite adhesive to form a stacked structure.

[0077] S3: filling the above-mentioned stacked structure into a graphite mold, preparing a graphene / copper composite material by a hot pressing sintering process, and setting the sintering pressure to 25 MPa;

[0078] First, a three-stage step temperature rise curing treatment is carried out: the temperature is raised to 75°C at a heating rate of 5°C / min, and the curing treatment is carried out for 1 hour. Then, the temperature is raised to 100°C at a heating rate of 3°C / min, and the curing treatment is carried out for 1 hour. Then, the temperature is raised to 140°C at a heating rate of 5°C / min, and the curing treatment is carried out for 2 hours.

[0079] After the three-stage step-by-step temperature curing treatment is completed, the temperature is increased to 450°C at a heating rate of 3°C / min and kept at this temperature for 30 minutes, then increased to 800°C at a rate of 5°C / min and kept at this temperature for 90 minutes. After sintering, it is cooled in the furnace to form a graphene / copper composite material.

[0080] Example 2

[0081] Example 2 is substantially the same as Example 1, except that, in Example 2, a copper layer of 30 μm is formed by controlling the electroplating time of copper.

[0082] The rest is implemented in the same manner as in Example 1 and will not be described again.

[0083] Example 3

[0084] Example 3 is substantially the same as Example 1, except that, in Example 3, a copper layer of 35 μm is formed by controlling the electroplating time of copper.

[0085] The rest is implemented in the same manner as in Example 1 and will not be described again.

[0086] Example 4

[0087] Example 4 is basically the same as Example 1, except that the pretreatment liquid used in Example 4 contains 20wt% KH550, the temperature of the pretreatment liquid is controlled at 60°C, and the graphene film is immersed in the pretreatment liquid for 60 minutes to form an adsorption film on the surface of the graphene film. The rest is implemented in the same way as Example 1, and will not be repeated here.

[0088] Example 5

[0089] Example 5 is basically the same as Example 1, except that the pretreatment liquid used in Example 5 contains 25 wt% sodium lauryl sulfate, the temperature of the pretreatment liquid is controlled at 60°C, and the graphene film is immersed in the pretreatment liquid for 60 minutes to form an adsorption film on the surface of the graphene film; after completion, the graphene film is taken out and washed with deionized water to obtain a graphene film with an adsorption film. The rest is implemented in the same way as Example 1, and will not be repeated here.

[0090] Comparative Example 1

[0091] The only difference between Comparative Example 1 and Example 1 is that Comparative Example 1 does not perform a surface pretreatment step, that is, copper electroplating is performed directly after the graphene film is cleaned.

[0092] The rest is implemented in the same manner as in Example 1 and will not be described again.

[0093] Embodiments 6 to 8

[0094] Examples 6 to 8 are substantially the same as Example 1, except that the formula of the metal composite adhesive used to bond two adjacent layers of coated graphene films in Examples 6 to 8 is changed as shown in Table 2.

[0095] Comparative Example 2

[0096] The only difference between Comparative Example 2 and Example 1 is that the formula of the metal composite adhesive used to bond two adjacent layers of coated graphene films in Comparative Example 2 is changed as shown in Table 2.

[0097] Table 2

[0098]

[0099] The present invention tests the relevant properties of the above copper-plated graphene film, and the test results are shown in Table 3.

[0100] The thermal conductivity of the coating is measured according to the conventional laser flash method in the industry. Taking into account the high thermal conductivity of the material and the anisotropy of graphene, the NETZSCH 467 laser thermal conductivity meter is used to measure the thermal conductivity of the sample in the planar direction.

[0101] The coating adhesion is tested according to ISO 2409:2020 cross-hatch method. The specific test method is to use a knife to scratch the surface with a hundred grids, stick the tape in the center of the grid, and then pull it off steadily, observe the phenomenon of paint film falling off, and make a judgment by calculating the state of the grid corresponding to the standard.

[0102] The coating surface roughness is measured by contact profilometer in accordance with ISO 4287, a standard for surface roughness published by the International Organization for Standardization.

[0103] Figure 1 , Figure 2 , Figure 3 The thermal expansion coefficients of the copper-plated graphene films in Examples 1, 2, and 3 are shown respectively.

[0104] Table 3 Related properties of copper-coated graphene film

[0105]

[0106] The present invention also tests the relevant properties of the graphene / copper composite material prepared above. The test results are shown in Table 4.

[0107] The thermal expansion coefficient was measured according to GB / T 4339-2008 standard of thermal expansion characteristic parameters of metal materials, using a thermomechanical analyzer TMA450 (EM), with a material test size of 5mm*5mm, and measuring in-plane direction.

[0108] Thermal conductivity The thermal conductivity of the material is measured according to the conventional laser flash method in the industry. Taking into account the high thermal conductivity of the material and the anisotropy of graphene, a NETZSCH 467 laser thermal conductivity meter is used with a 10mmx10mm mold to measure the thermal conductivity of the sample in the thickness direction.

[0109] Table 4 Relevant properties of graphene / copper composites

[0110]

[0111] Other embodiments that meet the technical solution of this application have also achieved better technical effects.

[0112] It can be seen that the copper electroplating method based on surface pretreatment and the hot pressing forming process provided by the present invention significantly improve the bonding force between graphene and copper. This strong bonding force not only improves the overall performance of the composite material, but also makes the composite material less likely to fall off or delaminate during long-term use. The graphene / copper composite material prepared by the present invention performs well in terms of thermal conductivity and thermal expansion; and shows good stability during the test process, and this stability improves the reliability of the composite material; compared with copper, it also shows excellent heat dissipation capacity in cooling. By optimizing the hot pressing forming process, the present invention makes the preparation process simpler, more efficient and less costly.

[0113] The various aspects, embodiments, features and examples of the present invention should be considered as illustrative in all aspects and are not intended to limit the present invention, the scope of the present invention is defined only by the claims. Other embodiments, modifications and uses will be apparent to those skilled in the art without departing from the spirit and scope of the claimed invention.

[0114] In addition, the inventors of this case also referred to the aforementioned embodiments and conducted experiments with other raw materials, process operations, and process conditions described in this specification, and obtained relatively ideal results.

[0115] Although the present invention has been described with reference to illustrative embodiments, it will be appreciated by those skilled in the art that various other changes, omissions and / or additions may be made without departing from the spirit and scope of the present invention and that the elements of the embodiments may be replaced by substantial equivalents. In addition, many modifications may be made without departing from the scope of the present invention to adapt specific circumstances or materials to the teachings of the present invention. Therefore, it is not intended herein to limit the present invention to the disclosed specific embodiments for performing the present invention, but it is intended that the present invention will include all embodiments within the scope of the appended claims. In addition, unless specifically stated, any use of the terms first, second, etc. does not indicate any order or importance, but rather uses the terms first, second, etc. to distinguish one element from another.

Claims

1. A method for preparing a copper-plated graphene film, characterized in that: include: Performing surface pretreatment on the graphene film to form an adsorption film on the surface of the graphene film to obtain an intermediate material; Forming a copper layer on the surface of the intermediate material having the adsorption film by electroplating to obtain a copper-plated graphene film; The adsorption film is formed by a pretreatment agent being bonded to the surface of the graphene film in the form of at least one of physical adsorption, chemical adsorption or electrostatic adsorption, and the pretreatment agent includes one or more combinations of acid compounds, silane coupling agents or ionic surfactants.

2. The preparation method according to claim 1, characterized in that: The surface pretreatment specifically includes: Providing a pretreatment solution, wherein the pretreatment solution comprises a pretreatment agent at a concentration of 20 to 50 wt %; The temperature of the pretreatment liquid is adjusted to 30-60° C., and the graphene film is immersed in the pretreatment liquid for 2-120 minutes to form the adsorption film on the surface of the graphene film; Preferably, when the pretreatment agent is an acid compound, the graphene film is immersed in the pretreatment liquid for 2 to 5 minutes; when the pretreatment agent is a silane coupling agent and / or an ionic surfactant, the graphene film is immersed in the pretreatment liquid for 30 to 120 minutes.

3. The preparation method according to claim 1 or 2, characterized in that: The acid compound includes one or more of sulfuric acid, hydrochloric acid, hydrofluoric acid or acetic acid; And / or, the silane coupling agent includes KH550 and / or KH560; And / or, the ionic surfactant includes sodium lauryl sulfate and / or sodium dodecyl sulfate.

4. The preparation method according to claim 1, characterized in that: The electroplating method specifically includes: using the intermediate material as a cathode and placing it together with an anode in an electroplating solution for copper plating, wherein the electroplating solution includes 10 to 50 g / L of copper salt and 30 to 70 g / L of a complexing agent, the pH value of the electroplating solution is 4 to 5, and the electroplating current density is 1 to 3 A / dm- 2 ; Preferably, the electroplating solution further comprises a brightener for improving the glossiness of the copper layer; Preferably, the anode is phosphor copper; Preferably, the electroplating time is 20 to 30 minutes; Preferably, the copper layer has a thickness of 20-40 μm.

5. A copper-plated graphene film, characterized in that: It is prepared by the method described in any one of claims 1 to 4.

6. A method for preparing a graphene / copper composite material, characterized in that: include: A copper-plated graphene film is prepared by the method according to any one of claims 1 to 4; A plurality of the copper-plated graphene films are stacked to form a stacked structure, and the stacked structure is subjected to a hot pressing and sintering process to form the graphene / copper composite material.

7. The preparation method according to claim 6, characterized in that: At least two adjacent copper-plated graphene films in the stacked structure are bonded by a metal composite adhesive, and the metal composite adhesive comprises, by weight: Polymer resin particles: 50-60 parts; Metal filler: 10-30 parts; Toughening agent: 1-10 parts; Coupling agent: 0.1-1 part; Curing agent: 0.1-0.2 parts; Organic solvent: 5 to 35 parts.

8. The preparation method according to claim 7, characterized in that: The resin raw material of the polymer resin particles includes one or a combination of epoxy resin, polyurethane or acrylate; And / or, the metal filler is metal powder, including copper powder and / or silver powder; And / or, the organic solvent comprises a combination of one or more of acetone, butanone, N,N-dimethylformamide or dichloromethane; And / or, the toughening agent includes one or more combinations of liquid polysulfide rubber, liquid carboxyl-terminated polybutadiene rubber, liquid hydroxyl-terminated polybutadiene rubber or polyvinyl acetal; And / or, the coupling agent includes KH-550 and / or KH-560; And / or, the curing agent comprises methyltetrahydrophthalic anhydride.

9. The preparation method according to claim 6, characterized in that: Also includes: Before the hot pressing sintering treatment, the stacked structure is subjected to multi-stage step-by-step heating, and then the temperature is raised to the sintering temperature to perform the hot pressing sintering treatment; wherein the multi-stage step-by-step heating includes: firstly raising the temperature to 70-80°C at a heating rate of 3-5°C / min and keeping the temperature for 1-2h, then raising the temperature to 90-110°C at a heating rate of 3-5°C / min and keeping the temperature for 1-2h, and then raising the temperature to 120-140°C at a heating rate of 3-5°C / min and keeping the temperature for 1-2h; And / or, the hot pressing sintering treatment includes: first heating the temperature to 400-450°C at a heating rate of 2.5-3°C / min and keeping it warm for 30-60min, then heating the temperature to 750-850°C at a heating rate of 5-10°C / min and keeping it warm for 60-90min; the sintering pressure of the hot pressing sintering treatment is 20-30MPa.

10. A graphene / copper composite material, characterized in that: It is prepared by the method described in any one of claims 7 to 9.

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