Graphene heat dissipation film for foldable screen mobile phone and preparation method thereof

Abstract

The present invention provides a graphene heat dissipation film for a foldable screen mobile phone and a preparation method thereof, which relates to the technical field of mobile phone heat dissipation. The graphene heat dissipation film of the present invention comprises a graphene superconducting film and a first graphene heat conductive film and a second graphene heat conductive film distributed on both sides of the graphene superconducting film; wherein the density of the first graphene heat conductive film and the second graphene heat conductive film are both 1.0-2.3g / cm 3 , the density of graphene superconducting film is 0.01-1.0g / cm 3 The present invention solves the technical problem that existing heat dissipation materials for mobile phone folding screens cannot withstand bending for millions of times and are difficult to connect to the two folding surfaces of the mobile phone folding screen over a large area through a rotating shaft, which in turn makes it difficult for the heat of the mobile phone to be transferred between the folding surfaces. The present invention achieves the technical effect that the graphene heat dissipation film placed on the folding surface of the entire mobile phone folding screen can be bent multiple times without breaking, making it easy for the heat generated by the mobile phone to be transferred between the folding surfaces.

Description

Technical Field

[0001] The present invention relates to the technical field of mobile phone heat dissipation, and in particular to a graphene heat dissipation film for a folding screen mobile phone and a preparation method thereof. Background Art

[0002] At present, 5G smartphones have been widely used. As 5G smartphones become more and more integrated and thinner, more and more parts of them generate heat. For smartphones, it is not only necessary to realize functions in a small space, but also to reasonably manage the heat generated, so that the phone can run more smoothly and extend its service life.

[0003] Currently, in the folding screen design of 5G smartphones, in order to avoid the total thickness of the phone being too thick, one folding surface (called folding surface 1) is usually used as a display screen, and other components are concentrated in the other folding surface (called folding surface 2). This makes folding surface 1 generate less heat, so the temperature is low, while folding surface 2 generates too much heat, so the temperature is too high, which will cause problems such as the phone running lag. At the same time, since the current heat dissipation material cannot meet the requirement of being able to withstand millions of bending times, the heat dissipation material cannot be connected to the two folding surfaces over a large area through the hinge, so it is difficult to transfer heat from folding surface 2 to folding surface 1.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] One of the purposes of the present invention is to provide a graphene heat dissipation film for a folding screen mobile phone, which can be bent multiple times without breaking when placed on the folding surface of the entire mobile phone folding screen, so that the heat generated by the mobile phone can be easily transferred between the folding surfaces.

[0006] The second purpose of the present invention is to provide a method for preparing a graphene heat dissipation film for a folding screen mobile phone, which has a simple process and a high quality rate.

[0007] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are adopted:

[0008] In a first aspect, a graphene heat dissipation film for a foldable screen mobile phone comprises a graphene superconducting film and a first graphene heat conductive film and a second graphene heat conductive film distributed on both sides of the graphene superconducting film;

[0009] The first graphene thermally conductive film is integrally formed with the second graphene thermally conductive film by being connected to the graphene superconducting film;

[0010] The density of the first graphene thermally conductive film and the second graphene thermally conductive film are independently 1.0-2.3 g / cm 3 ;

[0011] The density of the graphene superconducting film is 0.01-1.0 g / cm 3 .

[0012] Furthermore, the density of the first graphene thermally conductive film and the second graphene thermally conductive film are independently 1.6-2.3 g / cm 3 .

[0013] Furthermore, the thickness of the first graphene thermally conductive film and the second graphene thermally conductive film are independently 1-100 μm.

[0014] Furthermore, the thermal conductivity of the first graphene thermally conductive film and the second graphene thermally conductive film are independently 600-2200 W / mK, preferably 1000-2000 W / mK.

[0015] Furthermore, the density of the graphene superconducting film is 0.05-1.0 g / cm 3 , preferably 0.05-0.5g / cm 3 .

[0016] Furthermore, the thickness of the graphene superconducting film is 10-1000 μm, preferably 75-900 μm.

[0017] Furthermore, the thermal conductivity of the graphene superconducting film is 15-900 W / mK, preferably 20-600 W / mK.

[0018] In a second aspect, a method for preparing a graphene heat dissipation film for a foldable screen mobile phone comprises the following steps:

[0019] After the graphene film is calendered, the graphene heat dissipation film for the folding screen mobile phone is obtained.

[0020] Furthermore, the preparation method comprises the following steps:

[0021] The graphene film is placed in a mold and calendered to obtain the graphene heat dissipation film for the folding screen mobile phone. The mold includes an upper mold and a lower mold. The central part of the upper mold is set to a concave arc shape, and the two end parts are flat plate structures. The lower mold is a flat plate structure.

[0022] Furthermore, the pressure of the calendering treatment is 1000-20000 kN, preferably 5000-15000 kN.

[0023] Compared with the prior art, the present invention has at least the following beneficial effects:

[0024] The graphene heat dissipation film for foldable screen mobile phones provided by the present invention is composed of a graphene thermal conductive film and a graphene superconducting film of a specific density. The graphene thermal conductive film is distributed on both sides of the graphene superconducting film (the graphene superconducting film is equivalent to the rotating shaft). Since the density of the graphene thermal conductive film is greater than that of the graphene superconducting film, the state of the graphene thermal conductive film is relatively compact and the state of the graphene superconducting film is relatively fluffy. When bent, the heat dissipation film can release stress and strain at the graphene superconducting film (rotating shaft), so that it can achieve the effect of multiple bending without breaking; at the same time, the relatively fluffy graphene superconducting film can It plays a role in heat transfer, and can achieve the purpose of sliding and stretching during the opening or closing process of the folding screen mobile phone, thereby preventing the heat conductive film from being damaged by the heat dissipation film due to excessive tensile force during the closing process; therefore, the graphene heat dissipation film of the present invention can be placed on the folding surface of the entire folding screen mobile phone, and can be bent multiple times without breaking, so that the heat generated by the mobile phone can be easily and directly conducted between the folding surfaces, so that the heat generated by the mobile phone during operation can be reasonably distributed or managed, thereby solving the problem of operation jamming caused by excessive heat of the mobile phone and extending the service life of the mobile phone.

[0025] The present invention provides a method for preparing a graphene heat dissipation film for a folding screen mobile phone, which has a simple process and a high quality rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 A cross-sectional view of a graphene heat dissipation film for a foldable screen mobile phone provided in one embodiment of the present invention;

[0028] Figure 2 A cross-sectional view of a die for calendering according to one embodiment of the present invention.

[0029] Icon: 1-first graphene thermal conductive film; 2-second graphene thermal conductive film; 3-graphene superconducting film. DETAILED DESCRIPTION

[0030] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0031] According to a first aspect of the present invention, a graphene heat dissipation film for a foldable screen mobile phone is provided, comprising a graphene superconducting film and a first graphene heat conductive film and a second graphene heat conductive film distributed on both sides of the graphene superconducting film;

[0032] The first graphene thermal conductive film is connected to the second graphene thermal conductive film through the graphene superconducting film to form a whole;

[0033] The densities of the first graphene thermally conductive film and the second graphene thermally conductive film are independently 1.0-2.3 g / cm 3 , for example, it can be 1.0 g / cm 3 , 1.2g / cm 3 , 1.4g / cm 3 , 1.6g / cm 3 , 1.8g / cm 3 , 2.0g / cm 3 , 2.3g / cm 3 , but not limited to, is conducive to heat transfer;

[0034] The density of graphene superconducting film is 0.01-1.0g / cm 3 , for example, it can be 0.01 g / cm 3 , 0.02g / cm 3 , 0.04g / cm 3 , 0.06g / cm 3 , 0.08g / cm 3 , 0.1g / cm 3 , 0.2g / cm 3 , 0.4g / cm 3 , 0.6g / cm 3 , 0.8g / cm 3 , 1g / cm 3 , but not limited to this, can achieve stress and strain release and ensure excellent bending performance.

[0035] The graphene heat dissipation film for foldable screen mobile phones provided by the present invention is composed of a graphene thermal conductive film and a graphene superconducting film of a specific density. The graphene thermal conductive film is distributed on both sides of the graphene superconducting film (the graphene superconducting film corresponds to the position of the rotating shaft of the foldable screen mobile phone). Since the density of the graphene thermal conductive film is greater than that of the graphene superconducting film, the state of the graphene thermal conductive film is relatively compact while the state of the graphene superconducting film is relatively fluffy. When bent, the heat dissipation film can release stress and strain at the rotating shaft (graphene superconducting film). This can achieve the effect of multiple bending without breaking; at the same time, the relatively fluffy graphene superconducting film can play a role in heat transfer, and can achieve the purpose of sliding and stretching during the opening or closing process of the folding screen mobile phone, avoiding the heat conductive film from being damaged by excessive tensile force during the closing process; therefore, the graphene heat dissipation film for the folding screen mobile phone provided by the present invention can not only make the heat generated by the mobile phone quickly transfer from one side to the other side, but also has long-term bending resistance during the opening or closing process of the bend.

[0036] To sum up, the graphene heat dissipation film of the present invention can be placed on the folding surface of the entire folding screen mobile phone and can be bent multiple times without breaking, so that the heat generated by the mobile phone can be easily and directly conducted between the folding surfaces, so that the heat generated by the mobile phone during operation can be reasonably distributed or managed, thereby solving the problem of operation jamming caused by excessive heat of the mobile phone and extending the service life of the mobile phone.

[0037] In a preferred embodiment, the density of the first graphene thermally conductive film and the second graphene thermally conductive film can be independently 1.6-2.3 g / cm 3 , which is more conducive to heat transfer.

[0038] In a preferred embodiment, the thickness of the first graphene thermally conductive film and the second graphene thermally conductive film can independently be 1-100 μm, for example, 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, but not limited to this.

[0039] In a preferred embodiment, the thermal conductivity of the first graphene thermally conductive film and the second graphene thermally conductive film are independently 600-2200 W / mK, for example, 600 W / mK, 800 W / mK, 1000 W / mK, 1200 W / mK, 1400 W / mK, 1600 W / mK, 1800 W / mK, 2000 W / mK, 2200 W / mK, but not limited to this, and can preferably be 1000-2000 W / mK, which is more conducive to heat transfer.

[0040] In a preferred embodiment, the density of the graphene superconducting film can be 0.05-1.0 g / cm 3 , preferably 0.05-0.5g / cm 3 , which is beneficial to improve the stress and strain release effect during bending, thereby ensuring better bending resistance.

[0041] In a preferred embodiment, the thickness of the graphene superconducting film is 10-1000 μm, for example, 10 μm, 50 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, but is not limited thereto, and may preferably be 75-900 μm.

[0042] In a preferred embodiment, the thermal conductivity of the graphene superconducting film is 15-900 W / mK, for example, it can be 15 W / mK, 25 W / mK, 50 W / mK, 100 W / mK, 150 W / mK, 200 W / mK, 250 W / mK, 300 W / mK, 350 W / mK, 400 W / mK, 450 W / mK, 500 W / mK, 550 W / mK, 600 W / mK, 650 W / mK, 700 W / mK, 800 W / mK, 850 W / mK, 900 W / mK, but is not limited thereto, and can preferably be 20-600 W / mK, which is more conducive to heat transfer.

[0043] A typical graphene heat dissipation film for foldable screen mobile phones, such as Figure 1 As shown, it includes a relatively compact graphene thermal conductive film and a relatively fluffy graphene superconducting film. The relatively compact graphene thermal conductive film, i.e., the first graphene thermal conductive film 1 and the second graphene thermal conductive film 2, are distributed on both sides of the graphene superconducting film 3. The first graphene thermal conductive film 1 is connected to the second graphene thermal conductive film 2 through the graphene superconducting film 3 to form a whole.

[0044] The densities of the first graphene thermal conductive film 1 and the second graphene thermal conductive film 2 are independently 1.0-2.3 g / cm 3 , which can be preferably 1.6-2.3g / cm 3 The thickness of the first graphene thermally conductive film 1 and the second graphene thermally conductive film 2 are independently between 1-100 μm, and the thermal conductivity is independently 600-2200 W / mK, preferably 1000-2000 W / mK;

[0045] The density of the graphene superconducting film 3 is 0.05-1.0g / cm 3 , which may preferably be 0.05-0.5 g / cm 3The thickness thereof is 10-1000 μm, preferably 75-900 μm, and the thermal conductivity thereof is 15-900 W / mK, preferably 20-600 W / mK.

[0046] The graphene heat dissipation film for foldable screen mobile phones provided by the present invention solves the technical problem that the existing heat dissipation materials for foldable mobile phones cannot withstand bending millions of times, and therefore it is difficult to be connected to the two folding surfaces of the foldable mobile phone screen over a large area through a rotating shaft, which in turn makes it difficult for the heat of the mobile phone to be transferred between the folding surfaces. The graphene heat dissipation film is placed on the folding surface of the entire mobile phone folding screen and can be bent multiple times without breaking, thereby achieving the technical effect that the heat generated by the mobile phone can be easily transferred between the folding surfaces of the mobile phone folding screen.

[0047] According to a second aspect of the present invention, there is provided a method for preparing a graphene heat dissipation film for a foldable screen mobile phone as described in any one of the above, comprising the following steps:

[0048] After calendering treatment, the graphene film is used to obtain a graphene heat dissipation film for foldable screen mobile phones.

[0049] The present invention provides a method for preparing a graphene heat dissipation film for a folding screen mobile phone, which has a simple process and a high quality rate.

[0050] In a preferred embodiment, the preparation method of the present invention comprises the following steps:

[0051] The graphene film is placed in a mold and calendered to obtain a graphene heat dissipation film for foldable screen mobile phones;

[0052] The mold of the present invention comprises an upper mold and a lower mold, wherein the center portion of the upper mold is configured as a concave arc and the two end portions are flat plate structures, and the lower mold is a flat plate structure; the shape of the mold is as follows Figure 2 As shown, one side is completely flat, and there is a hollow arc in the middle of the other side. This specific shape of the mold can ensure that the density of the graphene film at the hollow arc position is lower than the density of the graphene films on both sides during the calendering process (the density of the graphene films on both sides is 1.0-2.3g / cm 3 , forming the first graphene thermal conductive film and the second graphene thermal conductive film), while the middle graphene film, namely the graphene superconducting film (corresponding to the position of the rotating shaft of the folding screen mobile phone), has a relatively fluffy state (density is 0.01-1.0g / cm 3 ).

[0053] In a preferred embodiment, the pressure of the calendering treatment is 1000-20000 kN. Typical but non-limiting pressures include 1000 kN, 2000 kN, 3000 kN, 4000 kN, 5000 kN, 6000 kN, 7000 kN, 8000 kN, 9000 kN, 10000 kN, 11000 kN, 12000 kN, 13000 kN, 14000 kN, 15000 kN, 16000 kN, 17000 kN, 18000 kN, 19000 kN and 20000 kN. It can be preferably 5000-15000 kN, which is more conducive to the formation of the graphene heat dissipation film of the present invention and ensures better thermal conductivity and bending resistance.

[0054] The present invention provides a method for preparing a graphene heat dissipation film for a folding screen mobile phone, which has a simple process and a high quality rate.

[0055] The present invention is further described below by way of examples. Unless otherwise specified, the materials in the examples were prepared according to existing methods or directly purchased from the market.

[0056] Example 1

[0057] A graphene heat dissipation film for foldable screen mobile phones, such as Figure 1 As shown, it includes a graphene superconducting film 3 and a first graphene thermal conductive film 1 and a second graphene thermal conductive film 2 distributed on both sides of the graphene superconducting film 3;

[0058] The first graphene thermal conductive film 1 is connected to the second graphene thermal conductive film 2 via the graphene superconducting film 3 to form a whole.

[0059] The preparation method of the graphene heat dissipation film for the foldable screen mobile phone is as follows:

[0060] First, a graphene oxide slurry is applied and heat-treated to obtain a graphene film with a thickness of 1000 μm. The obtained graphene film is then placed in a mold for calendering (the mold includes an upper mold, the center portion of the upper mold is configured as a concave arc and the two ends are flat-plate structures, and the lower mold is a flat-plate structure) to obtain a graphene heat dissipation film for stacked screen mobile phones;

[0061] The density of the first graphene thermal conductive film and the second graphene thermal conductive film after calendering is 2.0 g / cm 3 The thickness of the first graphene thermal conductive film and the second graphene thermal conductive film are both 50 μm, and the thermal conductivity of the first graphene thermal conductive film and the second graphene thermal conductive film are both 1546 W / mK;

[0062] The density of graphene superconducting film is 0.2g / cm 3, the thickness of the graphene superconducting film is 500μm and the thermal conductivity is 159W / mK;

[0063] The graphene heat dissipation film used in the folding screen mobile phone of this embodiment can be bent 300,000 times without breaking.

[0064] Example 2

[0065] The difference between this embodiment and embodiment 1 is that the density of the first graphene thermal conductive film and the second graphene thermal conductive film after calendering in this embodiment is 1.6 g / cm 3 , and the thickness is 62.5μm, the thermal conductivity is 1287W / mK; the density of graphene superconducting film is 0.3g / cm 3 The thickness of the graphene superconducting film is 333 μm, and the thermal conductivity is 242 W / mK; the rest are the same as in Example 1, and a graphene heat dissipation film for folding screen mobile phones is obtained, which can be bent 500,000 times without breaking.

[0066] Example 3

[0067] The difference between this embodiment and embodiment 1 is that the density of the first graphene thermal conductive film and the second graphene thermal conductive film after calendering in this embodiment is 1.8g / cm 3 , and the thickness is 55.6μm, the thermal conductivity is 1330W / mK; the density of graphene superconducting film is 0.25g / cm 3 The thickness of the graphene superconducting film is 400 μm, and the thermal conductivity of the graphene superconducting film is 203 W / mK; the rest are the same as in Example 1, and a graphene heat dissipation film for a folding screen mobile phone is obtained, which can be bent 400,000 times without breaking.

[0068] Example 4

[0069] The difference between this embodiment and embodiment 1 is that the density of the first graphene thermal conductive film and the second graphene thermal conductive film after calendering in this embodiment is 2.25g / cm 3 , and the thickness is 44μm, the thermal conductivity is 1678W / mK; the density of graphene superconducting film is 0.15g / cm 3 The thickness of the graphene superconducting film is 667 μm, and the thermal conductivity is 112 W / mK; the rest are the same as in Example 1, and a graphene heat dissipation film for folding screen mobile phones is obtained, which can be bent 170,000 times without breaking.

[0070] Example 5

[0071] The difference between this embodiment and embodiment 1 is that in this embodiment, the graphene oxide slurry is coated and heat-treated to obtain a graphene film with a thickness of 100 μm. The density of the first graphene thermal conductive film and the second graphene thermal conductive film obtained after calendering is 2.0 g / cm3 , and the thickness is 10μm, the thermal conductivity is 1678W / mK; the density of graphene superconducting film is 0.2g / cm 3 The thickness of the graphene superconducting film is 100 μm, and the thermal conductivity is 144 W / mK; the rest are the same as in Example 1, and a graphene heat dissipation film for folding screen mobile phones is obtained, which can be bent 900,000 times without breaking.

[0072] Example 6

[0073] The difference between this embodiment and embodiment 1 is that in this embodiment, the graphene oxide slurry is coated and heat-treated to obtain a graphene film with a thickness of 300 μm. The density of the first graphene thermal conductive film and the second graphene thermal conductive film obtained after calendering is 2.0 g / cm 3 , and the thickness is 30μm, the thermal conductivity is 1509W / mK; the density of graphene superconducting film is 0.2g / cm 3 The thickness of the graphene superconducting film is 300 μm, and the thermal conductivity is 126 W / mK; the rest are the same as in Example 1, and a graphene heat dissipation film for folding screen mobile phones is obtained, which can be bent 600,000 times without breaking.

[0074] Example 7

[0075] The difference between this embodiment and embodiment 1 is that in this embodiment, the graphene oxide slurry is coated and heat-treated to obtain a graphene film with a thickness of 900 μm. The density of the first graphene thermal conductive film and the second graphene thermal conductive film obtained after calendering treatment is 2.0 g / cm 3 , and the thickness is 90μm, the thermal conductivity is 1479W / mK; the density of graphene superconducting film is 0.2g / cm 3 The thickness of the graphene superconducting film is 900 μm, and the thermal conductivity is 102 W / mK; the rest are the same as in Example 1, and a graphene heat dissipation film for folding screen mobile phones is obtained, which can be bent 100,000 times without breaking.

[0076] Example 8

[0077] This embodiment is a method for preparing a graphene heat dissipation film for a foldable screen mobile phone provided in Examples 1-7, comprising the following steps:

[0078] The graphene film is placed in a mold for calendering treatment, and the excess part of the calendered graphene film is cut off to obtain a graphene heat dissipation film for foldable screen mobile phones.

[0079] Among them, the shape of the mold is as follows Figure 2 As shown, one side is completely flat, and the other side has a hollow arc in the middle;

[0080] During the calendering process, the mold of this embodiment can ensure that the graphene film at the hollow arc position will not be completely pressed, while the graphene film at other positions is completely calendered, thereby ensuring that the graphene film on both sides is compacted to form a relatively compact first graphene thermal conductive film and a second graphene thermal conductive film, and the graphene film in the middle forms a relatively fluffy graphene superconducting film.

[0081] Comparative Example 1

[0082] The difference between this comparative example and Example 1 is that the density of the graphene superconducting film in the graphene heat dissipation film provided in this comparative example is 0.008 g / cm 3 , the thickness is 1500μm, and the thermal conductivity of the graphene superconducting film is measured to be only 5W / mK. The rest are the same as in Example 1, and a graphene heat dissipation film for folding screen mobile phones is obtained. It can be bent 20,000 times without breaking, but it begins to break afterwards. This is mainly because the superconducting film is thicker at the bending part, and the stress of the outer graphene layer is large when bending and cannot be released. After multiple bending, the graphene superconducting film is partially broken.

[0083] It can be seen from the results of the above embodiments and comparative examples that the graphene heat dissipation film for the folding screen mobile phone provided by the present invention can release stress and strain at the rotating shaft (graphene superconducting film) when bent, so that it can achieve the effect of multiple bending without breaking. Therefore, the graphene heat dissipation film of the present invention can be placed on the folding surface of the entire folding screen mobile phone and be bent multiple times without breaking, so that the heat generated by the mobile phone can be easily and directly conducted between the folding surfaces, so that the heat generated by the mobile phone during operation can be reasonably distributed or managed, thereby solving the problem of operation jamming caused by excessive heat of the mobile phone and extending the service life of the mobile phone.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A graphene heat dissipation film for a foldable screen mobile phone, characterized in that: It comprises a graphene superconducting film and a first graphene heat-conducting film and a second graphene heat-conducting film distributed on both sides of the graphene superconducting film; The first graphene thermally conductive film is integrally formed with the second graphene thermally conductive film by being connected to the graphene superconducting film; The density of the first graphene thermally conductive film and the second graphene thermally conductive film are independently 1.0-2.3 g / cm 3 ; The density of the graphene superconducting film is 0.01-1.0 g / cm 3 ; The density of the graphene thermal conductive film is greater than the density of the graphene superconducting film.

2. The graphene heat dissipation film for a foldable screen mobile phone according to claim 1, characterized in that: The density of the first graphene thermally conductive film and the second graphene thermally conductive film are independently 1.6-2.3 g / cm 3 .

3. The graphene heat dissipation film for a foldable screen mobile phone according to claim 2, characterized in that: The thickness of the first graphene thermally conductive film and the second graphene thermally conductive film are independently 1-100 μm.

4. The graphene heat dissipation film for a foldable screen mobile phone according to claim 3, characterized in that: The thermal conductivity of the first graphene thermally conductive film and the second graphene thermally conductive film are independently 600-2200 W / mK.

5. The graphene heat dissipation film for a foldable screen mobile phone according to any one of claims 1 to 4, characterized in that: The density of the graphene superconducting film is 0.05-1.0 g / cm 3 .

6. The graphene heat dissipation film for a foldable screen mobile phone according to claim 5, characterized in that: The thickness of the graphene superconducting film is 10-1000 μm.

7. The graphene heat dissipation film for a foldable screen mobile phone according to claim 5, characterized in that: The thermal conductivity of the graphene superconducting film is 15-900 W / mK.

8. A method for preparing a graphene heat dissipation film for a foldable screen mobile phone according to any one of claims 1 to 7, characterized in that: The following steps are involved: The graphene film is calendered using a mold to obtain the graphene heat dissipation film for the folding screen mobile phone.

9. The preparation method according to claim 8, characterized in that The mold includes an upper mold and a lower mold. The center portion of the upper mold is configured to be a concave arc shape and both end portions are flat plate structures. The lower mold is also a flat plate structure.

10. The preparation method according to claim 8 or 9, characterized in that: The pressure of the calendering treatment is 1000-20000 kN.

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