A high thermal conductivity polyimide film, its preparation method and application

Abstract

The present invention provides a high thermal conductivity polyimide film, a preparation method thereof and an application thereof, relating to the technical field of polyimide films. The preparation method provided by the present invention comprises the following steps: mixing a thermal conductive filler with boron oxide and performing high-temperature nitridation to obtain a nitrided filler having a boron nitride coating structure; dispersing the nitrided filler and boron nitride nanosheets in a modified solution, separating and drying to obtain a modified filler; stirring and mixing the modified filler with a polyamic acid colloidal solution to obtain a composite colloidal solution, coating the composite colloidal solution into a film and imidizing to obtain the high thermal conductivity polyimide film. The present invention can significantly improve the out-of-plane thermal conductivity of the polyimide film, and at the same time, the method is simple and easy for large-scale industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of polyimide films, and particularly relates to a high thermal conductivity polyimide film, a preparation method thereof, and an application thereof. Background Art

[0002] With the rapid development of modern electronic information technology, electronic components are gradually developing towards miniaturization, functionality, integration, and high frequency. However, the heat accumulation problem generated during the operation of electronic components has become a core problem affecting efficiency, safety, and service life. Polyimide is a kind of polymer. In the molecular structure of polyimide, there is an imide group. The imide ring contained in the molecular main chain is formed by the polycondensation of compounds containing diamine and dianhydride in a polar aprotic solvent. Due to the excellent mechanical properties, good thermal properties and mechanical properties of polyimide films, they are widely used in the encapsulation of electronic components.

[0003] However, the intrinsic out-of-plane thermal conductivity (thermal conductivity in the direction perpendicular to the film plane) of conventional polyimide films is only 0.2 - 0.3 W / m·K. It is difficult to conduct heat quickly during the encapsulation process of electronic components and cannot meet the actual application. Therefore, in the prior art, polyimide films are usually modified to improve their thermal conductivity. For example, inorganic thermal conductive fillers are introduced into the polyimide matrix, and a three-dimensional thermal conduction path is constructed in the polyimide film to improve the intrinsic out-of-plane thermal conductivity of the polyamide film. Since boron nitride is an inorganic thermal conductive filler with high thermal conductivity, it is widely used to improve the thermal conductivity of polyimide films.

[0004] Currently, the utilization of boron nitride is mainly to make it into boron nitride nanosheets and then add them to the composite material with a high filling amount to improve the in-plane thermal conductivity of the sample. However, the addition of a high filling amount of boron nitride nanosheets will greatly affect the mechanical properties of the polymer itself, and the two-dimensional structure of the nanosheets is difficult to improve the out-of-plane thermal conductivity of the sample material. Therefore, there is an urgent need to provide a solution to improve the above problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a high thermal conductivity polyimide film, a preparation method thereof, and an application thereof, which can significantly improve the out-of-plane thermal conductivity of the polyimide film, and at the same time, the method is simple and easy for large-scale industrial production.

[0006] In a first aspect, a method for preparing a high thermal conductivity polyimide film provided by the present invention includes the following steps: mixing a thermal conductive filler with boron oxide and performing high-temperature nitridation to obtain a nitrided filler having a boron nitride coating structure; dispersing the nitrided filler and boron nitride nanosheets in a modified solution, separating and drying to obtain a modified filler; stirring and mixing the modified filler with a polyamic acid solution to obtain a composite solution, coating and forming the composite solution into a film, and imidizing to obtain a high thermal conductivity polyimide film.

[0007] In the preparation method provided by the present invention, after the thermal conductive particles are subjected to high-temperature nitridation and coated with boron nitride, the nitrided filler can have a high thermal conductivity similar to that of boron nitride. Thus, the nitrided filler and boron nitride nanosheets are mixed and modified to obtain a modified filler, and after being formed into a polyimide film, two-dimensional and three-dimensional homogeneous thermal conductive fillers are used to bridge points, lines, and surfaces, constructing a heat conduction path in the polyimide film, which can effectively improve the out-of-plane thermal conductivity of the film material. At the same time, the process of this method is simple and easy to industrialize on a large scale.

[0008] Optionally, in the process of mixing the thermal conductive filler with boron oxide and performing high-temperature nitridation, it includes: mixing the thermal conductive filler with the boron oxide to obtain a mixture to be nitrided; performing high-temperature nitridation on the mixture to be nitrided in a nitrogen-containing atmosphere at 600 - 1000 °C for 0.5 - 3 h.

[0009] Optionally, after mixing the thermal conductive filler with the boron oxide, the mass percentage of the boron oxide is 2 - 50%.

[0010] Optionally, the thermal conductive filler includes at least one of aluminum oxide, silicon oxide, silicon nitride, aluminum nitride, and silicon carbide.

[0011] Optionally, the average particle size of the thermal conductive filler is 0.5 - 5 μm.

[0012] Optionally, in the process of performing high-temperature nitridation on the mixture to be nitrided in a nitrogen-containing atmosphere at 600 - 1000 °C for 0.5 - 3 h, it includes: preheating the mixture to be nitrided in an inert atmosphere at 450 - 500 °C, and then heating it to 600 - 1000 °C at a nitrogen gas flow rate of 200 - 2000 mL / min and holding for 0.5 - 3 h.

[0013] Optionally, when dispersing the nitrided filler and boron nitride nanosheets in the modified solution, the mass percentage of the nitrided filler is 5 - 95%.

[0014] Optionally, when dispersing the nitrided filler and boron nitride nanosheets in the modified solution, the mass percentage of the nitrided filler is 50 - 90%.

[0015] Optionally, the thickness of the boron nitride nanosheets is 5 - 100 nm.

[0016] Optionally, the average planar size of the boron nitride nanosheets is 0.5 - 5 μm.

[0017] Optionally, when the nitride filler and the boron nitride nanosheets are dispersed in the modification solution, the solute of the modification solution includes at least one of phthalate coupling agents and nitrogen-containing functional group silane coupling agents.

[0018] Optionally, the mass ratio of the solute in the modification solution to any one of "the nitride filler and the boron nitride nanosheets" is 0.5 - 2%.

[0019] Optionally, the phthalate coupling agent includes at least one of PN-130, PN-101, and PN-102.

[0020] Optionally, the nitrogen-containing functional group silane coupling agent includes at least one of KH-540, KH-550, KH-560, KH-570, and KH-602.

[0021] Optionally, after the composite adhesive solution is coated and formed into a film and imidized to obtain a high thermal conductivity polyimide film, the mass percentage of the modified filler in the high thermal conductivity polyimide film is 5 - 50%.

[0022] In a second aspect, the present invention also provides a high thermal conductivity polyimide film prepared by any one of the above optional preparation methods.

[0023] In a third aspect, the present invention also provides a high thermal conductivity polyimide film prepared by any one of the above optional preparation methods, including being formed on the surface of an electronic component for rapid heat conduction. Description of the Drawings

[0024] Figure 1 It is a flowchart of a preparation method of a high thermal conductivity polyimide film provided by an embodiment of the present invention;

[0025] Figure 2 It is a SEM cross-sectional morphology diagram of the high thermal conductivity polyimide film prepared in Example 1 of the present invention;

[0026] Figure 3 It is a SEM morphology diagram of the nitride filler prepared in Example 1 of the present invention in an unground and undispersed state. Detailed Embodiments

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein shall have the ordinary meanings understood by those of ordinary skill in the art to which the present invention pertains.

[0028] Referring to Figure 1 , an embodiment of the present invention provides a method for preparing a high thermal conductivity polyimide film, including the following steps:

[0029] S1. Nitridation coating: Mix a thermal conductive filler with boron oxide and perform high-temperature nitridation to obtain a nitrided filler.

[0030] S2. Hybrid modification: Disperse the nitrided filler and boron nitride nanosheets in a modification solution, separate, and dry to obtain a modified filler.

[0031] S3. Coating and imidization: Stir and mix the modified filler with a polyamic acid solution to obtain a composite solution, and perform coating and imidization on the composite solution to obtain a high thermal conductivity polyimide film.

[0032] Actually, after performing step S1 of nitridation coating, the obtained nitrided filler has a thermal conductive particle as the core, and a layer of boron nitride is coated on the outside of the thermal conductive particle, so that the thermal conductivity of the nitrided filler can be improved and matched with the thermal conductivity of boron nitride.

[0033] In some embodiments, during the execution of step S1 of nitridation coating, the following sub-steps are included:

[0034] S1.1. Mix the thermal conductive filler with boron oxide to obtain a mixture to be nitrided.

[0035] S1.2. Perform high-temperature nitridation on the mixture to be nitrided in a nitrogen-containing atmosphere at 600 - 1000 °C for 0.5 - 3 h to obtain a nitrided filler.

[0036] In some embodiments, after mixing the thermal conductive filler with boron oxide in step S1.1, the mass percentage of boron oxide in the mixture is 2 - 50%, and the thermal conductive filler includes at least one of aluminum oxide, silicon oxide, silicon nitride, aluminum nitride, and silicon carbide.

[0037] Specifically, when mixing the thermal conductive filler with boron oxide in step S1.1, the used thermal conductive filler is three-dimensional particles with an average particle size of 0.5 - 5 μm. Using small particle size thermal conductive fillers is beneficial to the coating of boron nitride on the surface of the thermal conductive filler.

[0038] In some embodiments, during the execution of step S1.2, it includes: preheating the mixture to be nitrided in an inert atmosphere at 450 - 500 °C, and then heating it to 600 - 1000 °C at a nitrogen-containing gas flow rate of 200 - 2000 mL / min and holding for 0.5 - 3 h to obtain the nitrided filler.

[0039] Actually, during the execution of step S1.2, the mixture to be nitrided is loosely packed in a ceramic crucible and placed in the isothermal zone of the atmosphere furnace. After exhausting the atmosphere furnace with an inert gas, a high-temperature nitriding coating treatment is carried out on the mixture to be nitrided in the ceramic crucible by using a process of stepped heating and atmosphere conversion.

[0040] Actually, when carrying out the high-temperature nitriding coating treatment by using the process of stepped heating and atmosphere conversion during the execution of step S1.2, it includes: at an inert gas flow rate of 100 mL / min, the atmosphere furnace is heated to 450 - 500 °C at a rate of 0.5 - 10 °C / min and held for 0.5 - 1 h; after converting the inert gas to a nitrogen-containing gas, its flow rate is adjusted to 200 - 2000 mL / min, and the atmosphere furnace is heated to 600 - 1000 °C at a rate of 0.5 - 10 °C / min and held for 0.5 - 3 h to obtain the nitrided filler. Specifically, the inert gas used can be argon gas, and the nitrogen-containing gas used can be ammonia gas.

[0041] In some embodiments, during the execution of step S2 of mixing and modification, the nitrided filler and boron nitride nanosheets can be separately dispersed in the modification solution to separately obtain the modified nitrided filler and modified boron nitride nanosheets, and the modified nitrided filler and modified boron nitride nanosheets are mixed to obtain the modified filler. In some embodiments, during the execution of step S2 of mixing and modification, the nitrided filler and boron nitride nanosheets can also be pre-mixed and then put into the modification solution for dispersion, so as to directly obtain the modified filler.

[0042] In some embodiments, after mixing the nitrided filler and boron nitride nanosheets in step S2, the mass percentage of the nitrided filler in the mixture is 5 - 95%, preferably, the mass percentage of the nitrided filler in the mixture is 50 - 90%.

[0043] In some embodiments, when mixing the nitrided filler and boron nitride nanosheets in step S2, the thickness of the boron nitride nanosheets used is 5 - 100 nm, and the average planar size of the boron nitride nanosheets is 0.5 - 5 μm. Specifically, the boron oxide, thermal conductive filler, and boron nitride nanosheets used in steps S1 and S2 can all be commercially available conventional products.

[0044] In some embodiments, during the process of performing step S2 of mixing and modification, the solute of the modification solution used includes at least one of phthalate coupling agent and silane coupling agent with amino functional groups, and the solvent of the modification solution is a mixture of pure water and low molecular weight alcohol, where the low molecular weight alcohol is at least one of methanol, ethanol, and isopropanol. In fact, the concentration of the low molecular weight alcohol in the solvent of the modification solution is 80 - 95%.

[0045] Specifically, the phthalate coupling agent used includes at least one of PN-130, PN-101, and PN-102, and the silane coupling agent used can specifically be a vinyl silane coupling agent, and the vinyl silane coupling agent includes at least one of KH-540, KH-550, KH-560, KH-570, and KH-602.

[0046] In some embodiments, during the process of performing step S2 of mixing and modification, the mass ratio of the solute in the modification solution used to any one of "nitride filler and boron nitride nanosheets" is 0.5 - 2%.

[0047] In some embodiments, referring to Figure 1 , before the process of performing step S3, step Y1 of preparing a polyamic acid solution is pre-executed, including: mixing a dianhydride and a diamine monomer in a polar aprotic solvent, and preparing a polyamic acid solution through solution polycondensation. In fact, the execution order of step Y1 and step S2 can be arbitrarily swapped.

[0048] In fact, during the process of preparing the polyamic acid solution, the dianhydride used is any one of the following structural formulas:

[0049]

[0050] In fact, during the process of preparing the polyamic acid solution, the diamine monomer used is any one of the following structural formulas:

[0051]

[0052] In fact, during the process of preparing the polyamic acid solution, the polar aprotic solvent used includes any one of N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), and dimethyl sulfoxide (DMSO).

[0053] In some embodiments, when performing step S3 of stirring and mixing the modified filler and the polyamic acid solution, the mass fraction of the added modified filler is such that after the polyimide film is cured, the mass percentage of the modified filler in the polyimide film is 5 - 50%.

[0054] Actually, after performing step S3 to stir and mix the modified filler with the polyamic acid solution to obtain the composite solution, the solid content in the composite solution is 10 - 30%.

[0055] Actually, after obtaining the composite solution by performing step S3, the composite solution can be stored for standby in a low-temperature environment.

[0056] In some embodiments, when performing step S3 to coat and form a film with the composite solution, the substrate for film formation can be a smooth and clean glass plate or stainless steel plate. Specifically, when performing step S3 to coat and form a film with the composite solution, the composite solution is subjected to vacuum degassing and then coated to form a film.

[0057] In some embodiments, when performing step S3 for imidization treatment to obtain the high thermal conductivity polyimide film, the imidization treatment includes one of thermal imidization and chemical imidization. Actually, when performing chemical imidization treatment, a dehydrating agent and a catalyst need to be added to the composite solution, and the molar ratio of the dehydrating agent to the catalyst is 1∶(0.01 - 0.80).

[0058] Specifically, when adding the dehydrating agent and the catalyst in step S3 for chemical imidization, the dehydrating agent includes at least one of acetic anhydride, propionic anhydride, butyric anhydride, and benzoic anhydride, and the catalyst includes any one or a combination of pyridine and its derivatives, methylpyridine and its derivatives, dimethylpyridine, N,N - dimethylaminopyridine, quinoline, isoquinoline, and triethylamine.

[0059] Example 1

[0060] This Example 1 provides a method for preparing a high thermal conductivity polyimide film, including the following steps:

[0061] S1. Nitriding coating: Silica particles with an average particle size of 2.35 μm and boron oxide are fully mixed at a mass ratio of 9∶1 and loosely packed in a ceramic crucible. The ceramic crucible is placed in the isothermal zone of the atmosphere furnace hearth. The atmosphere furnace hearth is exhausted for 30 min at an argon flow rate of 100 mL / min. While maintaining the argon flow rate, the temperature is raised to 480 °C at a rate of 5 °C / min and held for 1 h. Then, the argon is converted to ammonia, and the temperature is raised to 800 °C at a rate of 1 °C / min at an ammonia flow rate of 1000 mL / min and held for 2 h. After cooling to room temperature in the furnace, it is taken out, dispersed, filtered, and dried to obtain the nitrided filler;

[0062] S2, mixed modification: the nitrided filler and the two-dimensional boron nitride nanosheets with an average thickness of 60nm and an average plane size of 3.5μm were mixed in a mass ratio of 45:55, and a modified solution (solute is KH-550 silane coupling agent, solvent is a mixture of pure water and ethanol in a mass ratio of 2:8, and the mass ratio of KH-550 silane coupling agent to two-dimensional boron nitride nanosheets is 2.4%) was added for infiltration and modification, and then filtered and dried to obtain a modified filler;

[0063] Y1. Preparation of polyamic acid glue solution: using biphenyltetracarboxylic acid dianhydride (BPDA) as dibasic acid anhydride, 4,4'-diaminodiphenyl ether (ODA) as diamine monomer, and using N,N-dimethylformamide (DMF) as polar aprotic solvent; stirring and dissolving BPDA in DMF, then adding ODA and stirring and dissolving, and preparing polyamic acid glue solution by solution polycondensation; wherein the added molar ratio of BPDA to ODA is 1:1;

[0064] S3. Coating to form a film and imidization: Add the modified filler to the polyamic acid adhesive solution, stir and disperse it thoroughly, filter and perform vacuum degassing to obtain a composite adhesive solution with a solid content of 20%, coat the composite adhesive solution on a smooth and clean glass plate substrate to form a film, and then perform imidization treatment to obtain a polyimide film with a modified filler content of 30%.

[0065] Example 2

[0066] This embodiment 2 provides a method for preparing a high thermal conductive polyimide film, which is different from the embodiment 1 in that:

[0067] S1, using aluminum oxide particles with an average particle size of 1.98 μm and boron oxide mixed in a mass ratio of 9:1 for nitriding coating;

[0068] S2, the mass ratio of the nitrided filler to the two-dimensional boron nitride nanosheets is 40:60; the solute of the modified solution is KH-560 silane coupling agent, the solvent is a mixture of pure water and ethanol in a mass ratio of 1:9, and the mass ratio of KH-560 silane coupling agent to the two-dimensional boron nitride nanosheets is 2%;

[0069] Y1. Pyromellitic dianhydride (PDMA) is used as the dibasic acid anhydride.

[0070] Example 3

[0071] This embodiment 3 provides a method for preparing a high thermal conductive polyimide film, which is different from the embodiment 1 in that:

[0072] S2, the mass ratio of nitrided filler to two-dimensional boron nitride nanosheets is 60:40;

[0073] S3. A composite adhesive solution with a solid content of 25% is prepared, and a polyimide film with a modified filler content of 35% is obtained after imidization treatment.

[0074] Example 4

[0075] Example 4 provides a method for preparing a highly thermally conductive polyimide film, which is different from Example 1 in that:

[0076] S1. Alumina particles with an average particle size of 1.98 μm and boron oxide are mixed at a mass ratio of 8:2 for nitridation coating; after heating to 450 °C and holding for 1 h, the temperature is raised to 1000 °C at a rate of 1 °C / min under an ammonia flow rate of 1000 mL / min and held for 2 h;

[0077] S2. The mass ratio of the nitrided filler to the two-dimensional boron nitride nanosheets is 50:50; the solute of the modification solution is KH-560 silane coupling agent, and the solvent is a mixture of pure water and ethanol with a mass ratio of 1:9, and the mass ratio of KH-560 silane coupling agent to the two-dimensional boron nitride nanosheets is 4%;

[0078] Y1. Pyromellitic dianhydride (PDMA) is used as the dianhydride.

[0079] Comparative Example 1

[0080] Comparative Example 1 provides a method for preparing a highly thermally conductive polyimide film, which is different from Example 1 in that: Step S1 is not carried out. In Step S2, silica particles with an average particle size of 2.35 μm and two-dimensional boron nitride nanosheets with an average thickness of 60 nm and a planar average size of 3.5 μm are mixed at a mass ratio of 45:55, and then added to a modification solution (the solute is KH-550 silane coupling agent, the solvent is a mixture of pure water and ethanol with a mass ratio of 2:8, and the mass ratio of KH-550 silane coupling agent to the mass of the two-dimensional boron nitride nanosheets is 2.4%) for infiltration modification and then filtered and dried to obtain a modified filler.

[0081] Performance detection:

[0082] The out-of-plane thermal conductivity of the highly thermally conductive polyimide films prepared in Examples 1 to 4 and Comparative Example 1 is measured using a laser flash thermal conductivity meter (NETZSCH, LFA467), and the results are shown in Table 1 below.

[0083] Table 1 Out-of-plane thermal conductivity of highly thermally conductive polyimide films

[0084] Example 1 Example 2 Example 3 Example 4 Comparative Example 1 <![CDATA[Out-of-plane thermal conductivity / W·m -1 ·K -1 > 2.36 2.18 2.59 2.08 1.23

[0085] It can be seen from Figure 2 that the nitrided filler and two-dimensional boron nitride nanosheets are uniformly dispersed in the polyimide matrix, and an out-of-plane thermal conduction path is constructed by the nitrided filler and two-dimensional boron nitride nanosheets; fromFigure 3 It can be seen that a layer of boron nitride ceramic shell is coated on the surface of the silica particles. As can be seen from Table 1, after the thermal conductive filler is coated with nitrogen in the embodiments of the present invention, the out-of-plane thermal conductivity of the polyimide film can be significantly improved.

[0086] Although the embodiments of the present invention have been described in detail above, it is obvious to those skilled in the art that various modifications and changes can be made to these embodiments. However, it should be understood that such modifications and changes are all within the scope and spirit of the present invention described in the claims. Moreover, the present invention described herein may have other embodiments and can be implemented or realized in various ways.

Claims

1. A method for preparing a high thermal conductive polyimide film, characterized in that: The following steps are involved: The thermal conductive filler is mixed with boron oxide and subjected to high-temperature nitridation to obtain a nitrided filler with a boron nitride coating structure; the nitrided filler and boron nitride nanosheets are dispersed in a modified solution and separated and dried to obtain a modified filler; the modified filler and polyamic acid glue are stirred and mixed to obtain a composite glue, and the composite glue is coated to form a film and imidized to obtain a high thermal conductive polyimide film.

2. The preparation method according to claim 1, characterized in that: The process of mixing thermally conductive fillers with boron oxide for high temperature nitriding includes: Mixing the thermally conductive filler with the boron oxide to obtain a mixture to be nitrided; The mixture to be nitrided is subjected to high-temperature nitridation in a nitrogen-containing atmosphere at 600° C.-1000° C. for 0.5 h-3 h.

3. The preparation method according to claim 1 or 2, characterized in that: When the thermal conductive filler is mixed with the boron oxide, the mass percentage of the boron oxide is 2%-50%.

4. The preparation method according to any one of claims 1 to 3, characterized in that: The thermally conductive filler includes at least one of aluminum oxide, silicon oxide, silicon nitride, aluminum nitride, and silicon carbide.

5. The preparation method according to any one of claims 1 to 3, characterized in that: The average particle size of the thermal conductive filler is 0.5 μm-5 μm.

6. The preparation method according to claim 2, characterized in that: The process of subjecting the mixture to be nitrided to high temperature for 0.5h-3h in a nitrogen-containing atmosphere at 600℃-1000℃ includes: preheating the mixture to be nitrided in an inert atmosphere at 450℃-500℃, heating it to 600℃-1000℃ at a nitrogen-containing flow rate of 200mL / min-2000mL / min and keeping it warm for 0.5h-3h.

7. The preparation method according to claim 1, characterized in that: When the nitrided filler and the boron nitride nanosheets are dispersed in the modified solution: the mass percentage of the nitrided filler is 5%-95%.

8. The preparation method according to claim 7, characterized in that: The mass percentage of the nitrided filler is 50%-90%.

9. The preparation method according to claim 1 or 7, characterized in that: The thickness of the boron nitride nanosheet is 5nm-100nm.

10. The preparation method according to claim 1 or 7, characterized in that: The average planar size of the boron nitride nanosheets is 0.5 μm-5 μm.

11. The preparation method according to claim 1, characterized in that: When the nitrided filler and the boron nitride nanosheets are dispersed in the modified solution: the solute of the modified solution includes at least one of a titanate coupling agent and a silane coupling agent containing an amino functional group.

12. The preparation method according to claim 11, characterized in that: The mass ratio of the solute in the modified solution to any one of "the nitrided filler and the boron nitride nanosheets" is 0.5%-2%.

13. The preparation method according to claim 11 or 12, characterized in that: The titanate coupling agent includes at least one of PN-130, PN-101 and PN-102.

14. The preparation method according to claim 11 or 12, characterized in that: The amino functional group-containing silane coupling agent includes at least one of KH-540, KH-550 and KH-602.

15. The preparation method according to claim 1, characterized in that: After the composite adhesive is coated and imidized to obtain a high thermal conductivity polyimide film, the mass percentage of the modified filler in the high thermal conductivity polyimide film is 5%-50%.

16. A high thermal conductive polyimide film prepared by the preparation method according to any one of claims 1 to 15.

17. An application of a high thermal conductivity polyimide film prepared by the preparation method according to any one of claims 1 to 15, characterized in that: The applications include molding on the surface of electronic components for rapid heat conduction.

Images