Graphene composite copper conductive film for electric heating film and preparation method thereof

Abstract

The present invention provides a graphene-composite copper conductive film for an electric heating film and a preparation method thereof. The method comprises adding graphene oxide to water and stirring to obtain a graphene oxide slurry; adding a copper sulfate solution to the graphene oxide slurry to obtain a graphene oxide / copper sulfate composite slurry; coating the graphene oxide / copper sulfate composite slurry on a substrate to a coating thickness of greater than or equal to 1 mm; sequentially feeding the substrate into a tunnel chamber and a tunnel furnace filled with hydrogen iodide vapor to obtain a fluffy graphene-composite nano-copper film; sequentially placing the fluffy graphene-composite nano-copper film in a carbonization furnace and a graphitization furnace to obtain a heat-treated fluffy graphene-composite nano-copper film; and placing the heat-treated fluffy graphene-composite nano-copper film in a vacuum high-temperature hot-pressing sintering furnace. By updating the formulation and process, nano-copper is introduced, thereby improving the tear strength of the graphene-composite copper conductive film while ensuring good electrical conductivity.

Description

Technical Field

[0001] The present invention belongs to the technical field of electric heating, and in particular relates to a graphene composite copper conductive film for an electric heating film and a preparation method thereof. Background Art

[0002] This section merely provides background information related to the present disclosure and is not necessarily prior art.

[0003] Graphene is an emerging strategic material developed in the 21st century. Graphene electric heating films have seen rapid growth in the graphene industry, characterized by low manufacturing costs and environmentally friendly production processes. In particular, graphene electric heating films can emit far-infrared radiation that resonates well with the human body, while also offering advantages such as easy surface heating and rapid heating rates. These advantages have made them a hot topic of research in the electric heating film field.

[0004] The graphene conductive film currently used in mainstream graphene electric heating membranes is made from graphene slurry. The process involves mixing graphene, conductive carbon black, resin, and solvent to form a slurry, which is then coated, dried, and wound. Due to the presence of resin, this graphene conductive film has poor thermal stability. At high operating temperatures (>90°C), its service life is less than 200 hours.

[0005] Graphene thermal conductive film, which is widely used in mobile phones, is composed of pure graphene and does not contain resin. Using it in graphene electric heating films can significantly improve their thermal stability. Test data shows that after aging at 150°C for 1000 hours, the resistance of the graphene thermal conductive film remains essentially unchanged. Therefore, using this material as a heating material can solve the problem of the low high-temperature service life of traditional graphene electric heating films. However, because the above-mentioned graphene thermal conductive film has good thermal stability due to the lack of resin, its tear strength is also low (<1kN / m), which cannot meet the performance requirements of electric heating films for rubbing resistance. Summary of the Invention

[0006] In view of the above problems, the first aspect of the present invention provides a method for preparing a graphene composite copper conductive film for an electric heating film, comprising:

[0007] Slurrying: adding graphene oxide to water and stirring to obtain graphene oxide slurry;

[0008] Compounding: adding a copper sulfate solution to the graphene oxide slurry to obtain a graphene oxide / copper sulfate composite slurry;

[0009] Coating: coating the graphene oxide / copper sulfate composite slurry on a substrate with a coating thickness greater than or equal to 1 mm;

[0010] Reduction: the substrate is sequentially placed into a tunnel chamber and a tunnel furnace filled with hydrogen iodide vapor to obtain a fluffy graphene composite nano-copper film;

[0011] Heat treatment: first placing the fluffy graphene composite nano-copper film in a carbonization furnace, and then placing it in a graphitization furnace to obtain a heat-treated fluffy graphene composite nano-copper film;

[0012] Vacuum hot pressing: placing the heat-treated fluffy graphene composite nano-copper film in a vacuum high-temperature hot pressing sintering furnace at 1400° C.-1800° C., with a pressure of 10-100 tons and a vacuum pressing time of 10-30 minutes.

[0013] In the reduction step of the above preparation method, graphene oxide is reduced to graphene in a tunnel chamber of hydrogen iodide vapor, and copper sulfate is reduced to nano-copper in the tunnel chamber of hydrogen iodide vapor and adheres to the surface of graphene; in the heat treatment step, heteroatoms are removed and the graphene lattice is repaired; in the vacuum hot pressing step, the air inside the graphene composite nano-copper film is discharged, and the molten nano-copper fills the gaps between the graphene sheets. After cooling, a graphene composite copper conductive film for an electric heating film is obtained.

[0014] Since copper has good conductivity and ductility, the addition of copper enables the graphene conductive film to maintain good conductivity while significantly improving the tear strength.

[0015] In some embodiments of the present invention, the coating thickness is 1-2 mm.

[0016] In some embodiments of the present invention, the solid content of the graphene oxide slurry is 2 wt%-6 wt%.

[0017] In some embodiments of the present invention, the concentration of the copper sulfate solution is 0.01-0.1 mol / L.

[0018] In some embodiments of the present invention, the mass ratio of copper in the copper sulfate solution to graphene in the graphene oxide is 1:0.2-1.

[0019] In some embodiments of the present invention, the temperature in the tunnel furnace is 70°C-90°C, the temperature in the carbonization furnace is 1300°C-1500°C, the time in the carbonization furnace is 2-6 hours, the temperature in the graphitization furnace is 2850°C-3000°C, and the time in the carbonization furnace is 6-10 hours.

[0020] A second aspect of the present invention provides a graphene composite copper conductive film for an electric heating film, which is obtained by the preparation method of the graphene composite copper conductive film for an electric heating film in any of the above technical solutions.

[0021] The graphene composite copper conductive film for electric heating film in the embodiment of the present invention has the same beneficial effects as the graphene composite copper conductive film for electric heating film prepared by the preparation method of the graphene composite copper conductive film for electric heating film in any of the above technical solutions, which will not be repeated here.

[0022] In some embodiments of the present invention, the mass ratio of copper to graphene in the graphene-composite copper conductive film for the electric heating film is 1:0.2-1.

[0023] In some embodiments of the present invention, the thickness of the graphene composite copper conductive film used for the electric heating film is 40-80 μm.

[0024] In some embodiments of the present invention, the tear strength of the graphene composite copper conductive film for the electric heating film is 5-10 KN / m. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present invention. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:

[0026] Figure 1 The present invention is a flowchart of a method for preparing a graphene composite copper conductive film for an electric heating film according to an embodiment of the present invention. DETAILED DESCRIPTION

[0027] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0028] It should be understood that the terms used herein are for the purpose of describing specific example embodiments only and are not intended to be limiting. Unless the context clearly indicates otherwise, as used herein, the singular forms "a," "an," and "the" may also be intended to include the plural forms. The terms "comprise," "include," "contain," and "have" are inclusive and, therefore, specify the presence of the stated features, steps, operations, elements, and / or parts, but do not preclude the presence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof.

[0029] Although the terms first, second, third, etc. can be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates otherwise, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teaching of the example embodiments.

[0030] For ease of description, spatially relative terms may be used herein to describe the relationship of one element or feature relative to another element or feature as shown in the figures, such as "inside," "outside," "inside," "outside," "below," "beneath," "above," and the like. Such spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is flipped, an element described as "below" or "below" another element or feature would then be oriented as "above" or "above" another element or feature. Thus, the example term "below" can include both above and below orientations. The device may be otherwise oriented (rotated 90 degrees or in other orientations) and the spatially relative descriptors used herein are interpreted accordingly.

[0031] The disclosure below provides many different embodiments or examples for realizing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numbers and / or reference letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0032] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0033] like Figure 1 As shown, the first aspect of the present invention provides a method for preparing a graphene composite copper conductive film for an electric heating film, comprising:

[0034] Slurrying: adding graphene oxide to water and stirring to obtain graphene oxide slurry;

[0035] Compounding: adding copper sulfate solution to graphene oxide slurry to obtain graphene oxide / copper sulfate composite slurry;

[0036] Coating: coating the graphene oxide / copper sulfate composite slurry on the substrate with a coating thickness greater than or equal to 1 mm;

[0037] Reduction: The substrate is sequentially placed into a tunnel chamber and a tunnel furnace filled with hydrogen iodide vapor to obtain a fluffy graphene composite nano-copper film;

[0038] Heat treatment: first placing the fluffy graphene composite nano-copper film in a carbonization furnace, and then placing it in a graphitization furnace to obtain a heat-treated fluffy graphene composite nano-copper film;

[0039] Vacuum hot pressing: Place the heat-treated fluffy graphene composite nano-copper film in a vacuum high-temperature hot pressing sintering furnace at 1400℃-1800℃, with a pressure of 10-100 tons and a vacuum pressing time of 10-30 minutes.

[0040] In the reduction step of the above preparation method, graphene oxide is reduced to graphene in a tunnel chamber of hydrogen iodide vapor, and copper sulfate is reduced to nano-copper in the tunnel chamber of hydrogen iodide vapor and adheres to the surface of graphene; in the heat treatment step, heteroatoms are removed and the graphene lattice is repaired; in the vacuum hot pressing step, the air inside the graphene composite nano-copper film is discharged, and the molten nano-copper fills the gaps between the graphene sheets. After cooling, a graphene composite copper conductive film for an electric heating film is obtained.

[0041] Since copper has good conductivity and ductility, the addition of copper enables the graphene conductive film to maintain good conductivity while significantly improving the tear strength.

[0042] In some embodiments of the present invention, the coating thickness is 1-2 mm.

[0043] In some embodiments of the present invention, the solid content of the graphene oxide slurry is 2 wt%-6 wt%.

[0044] In some embodiments of the present invention, the concentration of the copper sulfate solution is 0.01-0.1 mol / L.

[0045] In some embodiments of the present invention, the mass ratio of copper in the copper sulfate solution to graphene in the graphene oxide is 1:0.2-1.

[0046] In some embodiments of the present invention, the temperature in the tunnel furnace is 70°C-90°C, the temperature in the carbonization furnace is 1300°C-1500°C, the time in the carbonization furnace is 2-6 hours, the temperature in the graphitization furnace is 2850°C-3000°C, and the time in the carbonization furnace is 6-10 hours.

[0047] The following will illustrate the preparation of an electric heating film composed of a graphene / polyurethane composite film in a comparative example and the preparation of a graphene composite copper conductive film for an electric heating film in different embodiments:

[0048] Example 1

[0049] Slurry preparation: Graphene oxide was added to water and stirred in a double planetary vacuum mixer to obtain a graphene oxide slurry with a solid content of 6 wt%;

[0050] Compounding: adding a 0.05 mol / L copper sulfate solution to a graphene oxide slurry at a copper to graphene mass ratio of 1:0.2, and stirring thoroughly to obtain a graphene oxide / copper sulfate composite slurry;

[0051] Coating: The graphene oxide / copper sulfate composite slurry is coated on the substrate with a coating thickness of 1 mm;

[0052] Reduction: First, the substrate is sent into a tunnel chamber filled with hydrogen iodide vapor. The graphene oxide is reduced to graphene, and the copper sulfate is reduced to nano-copper attached to the graphene surface. Then the substrate is sent into a tunnel furnace at a temperature of 70°C. The water evaporates to obtain a fluffy graphene composite nano-copper film.

[0053] Heat treatment: first, the fluffy graphene composite nano-copper film is placed in a carbonization furnace at 1300°C for 4 hours, and then treated in a graphitization furnace at 3000°C for 10 hours to repair the graphene lattice and remove heteroatoms, thereby obtaining a heat-treated fluffy graphene composite nano-copper film;

[0054] Vacuum Hot Pressing: The heat-treated fluffy graphene-composite nano-copper film is placed in a vacuum high-temperature hot-pressing furnace at 1400°C and 100 tons of pressure for 30 minutes. At high temperatures, the copper nanoparticles melt. Under the combined effects of pressure and vacuum, the air inside the heat-treated fluffy graphene-composite nano-copper film is expelled, reducing the spacing between graphene sheets. The gaps between the sheets are then filled with molten copper. After cooling, the resulting graphene-composite copper conductive film is used as an electric heating film.

[0055] The above-mentioned graphene composite copper conductive film was tested by a thermogravimetric analyzer, and the mass ratio of copper and graphene was 1:0.2. The thickness was tested by a thickness gauge and was 40μm. The tear strength was tested by a universal testing machine according to GB / T16578.1-2008 and was 8kN / m.

[0056] Example 2

[0057] Slurry preparation: Graphene oxide was added to water and stirred in a double planetary vacuum mixer to obtain a graphene oxide slurry with a solid content of 2 wt%;

[0058] Compounding: adding a 0.1 mol / L copper sulfate solution to a graphene oxide slurry in a mass ratio of copper to graphene of 1:1, and stirring thoroughly to obtain a graphene oxide / copper sulfate composite slurry;

[0059] Coating: The graphene oxide / copper sulfate composite slurry is coated on the substrate with a coating thickness of 1 mm;

[0060] Reduction: First, the substrate is sent into a tunnel chamber filled with hydrogen iodide vapor. The graphene oxide is reduced to graphene, and the copper sulfate is reduced to nano-copper attached to the graphene surface. The substrate is then sent into a tunnel furnace at a temperature of 90°C. The water evaporates to obtain a fluffy graphene composite nano-copper film.

[0061] Heat treatment: first, the fluffy graphene composite nano-copper film is placed in a carbonization furnace at 1500°C for 4 hours, and then treated in a graphitization furnace at 3000°C for 6 hours to repair the graphene lattice and remove heteroatoms, thereby obtaining a heat-treated fluffy graphene composite nano-copper film;

[0062] Vacuum Hot Pressing: The heat-treated fluffy graphene-composite nano-copper film is placed in a vacuum high-temperature hot-pressing furnace at 1800°C and 50 tons of pressure for 10 minutes. At high temperatures, the copper nanoparticles melt. Under the combined effects of pressure and vacuum, the air inside the heat-treated fluffy graphene-composite nano-copper film is expelled, reducing the spacing between graphene sheets. The gaps between the sheets are then filled with molten copper. After cooling, the resulting graphene-composite copper conductive film is used as an electric heating film.

[0063] The above-mentioned graphene composite copper conductive film was tested by a thermogravimetric analyzer, and the mass ratio of copper and graphene was 1:1. The thickness was tested by a thickness gauge and was 40μm. The tear strength was tested by a universal testing machine according to GB / T16578.1-2008 and was 5kN / m.

[0064] Example 3

[0065] Slurry preparation: Graphene oxide was added to water and stirred in a double planetary vacuum mixer to obtain a graphene oxide slurry with a solid content of 6 wt%;

[0066] Compounding: adding a 0.05 mol / L copper sulfate solution to a graphene oxide slurry at a copper to graphene mass ratio of 1:0.2, and stirring thoroughly to obtain a graphene oxide / copper sulfate composite slurry;

[0067] Coating: The graphene oxide / copper sulfate composite slurry is coated on the substrate with a coating thickness of 2 mm;

[0068] Reduction: First, the substrate is sent into a tunnel chamber filled with hydrogen iodide vapor. The graphene oxide is reduced to graphene, and the copper sulfate is reduced to nano-copper attached to the graphene surface. Then the substrate is sent into a tunnel furnace at a temperature of 70°C. The water evaporates to obtain a fluffy graphene composite nano-copper film.

[0069] Heat treatment: first, the fluffy graphene composite nano-copper film is placed in a carbonization furnace at 1300°C for 4 hours, and then treated in a graphitization furnace at 3000°C for 10 hours to repair the graphene lattice and remove heteroatoms, thereby obtaining a heat-treated fluffy graphene composite nano-copper film;

[0070] Vacuum Hot Pressing: The heat-treated fluffy graphene-composite nano-copper film is placed in a vacuum high-temperature hot-pressing furnace at 1400°C and 100 tons of pressure for 30 minutes. At high temperatures, the copper nanoparticles melt. Under the combined effects of pressure and vacuum, the air inside the heat-treated fluffy graphene-composite nano-copper film is expelled, reducing the spacing between graphene sheets. The gaps between the sheets are then filled with molten copper. After cooling, the resulting graphene-composite copper conductive film is used as an electric heating film.

[0071] The above-mentioned graphene composite copper conductive film was tested by a thermogravimetric analyzer, and the mass ratio of copper and graphene was 1:0.2. The thickness was tested by a thickness gauge and was 80μm. The tear strength was tested by a universal testing machine according to GB / T16578.1-2008 and was 10kN / m.

[0072] Comparative Example 1 (pure graphene conductive film, compared with Example 1)

[0073] Slurry preparation: Graphene oxide was added to water and stirred in a double planetary vacuum mixer to obtain a graphene oxide slurry with a solid content of 6 wt%;

[0074] Coating: The graphene oxide slurry is coated on the substrate with a coating thickness of 1 mm;

[0075] Heat treatment: The coated graphene oxide slurry is first placed in a carbonization furnace at 1300°C for 4 hours, and then treated in a graphitization furnace at 3000°C for 10 hours to repair the graphene lattice and remove heteroatoms, thereby obtaining a heat-treated graphene conductive film;

[0076] Vacuum hot pressing: The heat-treated graphene conductive film was sent to a vacuum high-temperature hot pressing sintering furnace at 1400°C and 100 tons of pressure for 30 minutes to obtain a graphene conductive film with a thickness of 40μm. The tear strength was tested by a universal testing machine according to GB / T16578.1-2008 and was 0.5kN / m.

[0077] By comparing Examples 1, 2, and 3 with Comparative Example 1, it can be seen that the tear strength of Examples 1 to 3 is greatly improved compared to Comparative Example 1. By analyzing the mass ratio of copper to graphene in the samples, it can be seen that the introduction of copper plays a decisive role in improving the tear strength.

[0078] A second aspect of the present invention provides a graphene composite copper conductive film for an electric heating film, which is obtained by the preparation method of the graphene composite copper conductive film for an electric heating film in any of the above technical solutions.

[0079] The graphene composite copper conductive film for electric heating film in the embodiment of the present invention has the same beneficial effects as the graphene composite copper conductive film for electric heating film prepared by the preparation method of the graphene composite copper conductive film for electric heating film in any of the above technical solutions, which will not be repeated here.

[0080] In some embodiments of the present invention, the mass ratio of copper to graphene in the graphene-composite copper conductive film used for the electric heating film is 1:0.2-1.

[0081] In some embodiments of the present invention, the thickness of the graphene composite copper conductive film used for the electric heating film is 40-80 μm.

[0082] In some embodiments of the present invention, the tear strength of the graphene composite copper conductive film used for the electric heating film is 5-10 KN / m.

[0083] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for preparing a graphene composite copper conductive film for an electric heating film, characterized in that: include: Slurrying: adding graphene oxide to water and stirring to obtain graphene oxide slurry; Compounding: adding a copper sulfate solution to the graphene oxide slurry to obtain a graphene oxide / copper sulfate composite slurry; Coating: coating the graphene oxide / copper sulfate composite slurry on a substrate with a coating thickness greater than or equal to 1 mm; Reduction: the substrate is sequentially placed into a tunnel chamber and a tunnel furnace filled with hydrogen iodide vapor to obtain a fluffy graphene composite nano-copper film; Heat treatment: first placing the fluffy graphene composite nano-copper film in a carbonization furnace, and then placing it in a graphitization furnace to obtain a heat-treated fluffy graphene composite nano-copper film; Vacuum hot pressing: placing the heat-treated fluffy graphene composite nano-copper film in a vacuum high-temperature hot pressing sintering furnace at 1400° C.-1800° C., with a pressure of 10-100 tons and a vacuum pressing time of 10-30 minutes.

2. The method for preparing a graphene composite copper conductive film for an electric heating film according to claim 1, characterized in that: The coating thickness is 1-2mm.

3. The method for preparing a graphene composite copper conductive film for an electric heating film according to claim 1, wherein: The solid content of the graphene oxide slurry is 2 wt%-6 wt%.

4. The method for preparing a graphene composite copper conductive film for an electric heating film according to claim 1, wherein: The concentration of the copper sulfate solution is 0.01-0.1 mol / L.

5. The method for preparing a graphene composite copper conductive film for an electric heating film according to claim 1, wherein: The mass ratio of copper in the copper sulfate solution to graphene in the graphene oxide is 1:0.2-1.

6. The method for preparing a graphene composite copper conductive film for an electric heating film according to claim 1, characterized in that: The temperature in the tunnel furnace is 70°C-90°C, the temperature in the carbonization furnace is 1300°C-1500°C, the time in the carbonization furnace is 2-6 hours, the temperature in the graphitization furnace is 2850°C-3000°C, and the time in the carbonization furnace is 6-10 hours.

7. A graphene composite copper conductive film for an electric heating film, obtained by the preparation method of the graphene composite copper conductive film for an electric heating film according to any one of claims 1 to 6, wherein the copper occupies the gaps between the graphene sheets in the graphene composite copper conductive film for an electric heating film.

8. The graphene composite copper conductive film for electric heating film according to claim 7, characterized in that: The mass ratio of copper to graphene in the graphene composite copper conductive film for the electric heating film is 1:0.2-1.

9. The graphene composite copper conductive film for electric heating film according to claim 7, characterized in that: The thickness of the graphene composite copper conductive film used for the electric heating film is 40-80 μm.

10. The graphene composite copper conductive film for electric heating film according to claim 7, characterized in that: The tear strength of the graphene composite copper conductive film for the electric heating film is 5-10 KN / m.

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