Boron nitride heat-conducting gasket as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of heat-conducting materials, and discloses a boron nitride heat-conducting gasket and a preparation method and application thereof, the preparation method comprises the following steps: dispersing hexagonal boron nitride in isopropanol, sanding, and adding a coupling agent for coupling modification to obtain two-dimensional boron nitride slurry B; adding glue, uniformly mixing, pouring into a tool, oscillating and drying to obtain a semi-finished product of the boron nitride heat-conducting gasket; and taking out the semi-finished boron nitride heat-conducting gasket and cutting to obtain the boron nitride heat-conducting gasket. According to the invention, the dispersibility and binding force of the two-dimensional boron nitride in a glue matrix are improved through coupling modification, the filling amount of the two-dimensional boron nitride is increased so as to enhance a heat conduction path, and the hardness is reduced; the two-dimensional boron nitride is matched with the tool for vibration stacking forming, the interlayer bonding defect caused by layer-by-layer stacking is avoided, and the heat conduction performance of the boron nitride heat conduction gasket is overall improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermal conductive materials, and in particular relates to a boron nitride thermal conductive gasket and a preparation method and application thereof. Background Art

[0002] Boron nitride thermal pads are polymer composite materials with boron nitride as the core thermally conductive component. Boron nitride's excellent thermal conductivity allows for efficient heat transfer and is widely used in electronic components, communications equipment, new energy vehicles, and other fields. As an interfacial thermal conductive medium, boron nitride thermal pads effectively address heat accumulation during device operation, ensuring stable operation of electronic equipment at optimal temperatures. They are a key material for enhancing the reliability and service life of electronic equipment. However, the existing preparation technology of boron nitride thermal conductive gaskets still has many problems. At present, the production process of boron nitride thermal conductive gaskets mostly uses acrylic resin pressure-sensitive adhesive as the base material to fix the two-dimensional boron nitride. The production process is usually as follows: first, a thin film with a thickness of 80μm is formed by coating, and then the film is stacked layer by layer to the required thickness. Then, the overall structure is formed by hot pressing. Finally, it needs to be cut in the vertical direction to achieve the conversion of horizontal thermal conductivity to vertical thermal conductivity. On the one hand, this process suffers from the poor dispersion and weak interfacial bonding of the two-dimensional boron nitride used in the resin matrix, making it impossible to achieve the required high filling ratio of the two-dimensional boron nitride in the resin matrix. The resulting thermal conductive gasket has low thermal conductivity and cannot meet the high thermal conductivity requirements of high-power electronic devices. On the other hand, the layers of film in the layer-by-layer stacking process are bonded together using a non-reactive acrylic resin pressure-sensitive adhesive. When used in electronic devices, the acrylic resin pressure-sensitive adhesive is prone to softening under continuous high-temperature environments, causing the directional arrangement of the boron nitride structure to collapse, resulting in a rapid decrease in the thermal conductivity of the thermal conductive gasket in the vertical direction. In severe cases, this may cause the terminal device to burn out, greatly affecting the safety and stability of the device operation. In addition, because the single layer material in the layer-by-layer stacking process must maintain high hardness and rigidity to achieve peeling, and the overall hardness after multi-layer stacking is mainly determined by the filling amount of two-dimensional boron nitride, the overall hardness after stacking is extremely high, limiting the processing adaptability of the material. Summary of the Invention

[0003] The present invention aims to improve at least one technical problem in the background technology.

[0004] A first aspect of the present invention provides a method for preparing a boron nitride thermally conductive gasket, comprising the following steps: Dispersing hexagonal boron nitride in a first solvent and sand-milling to obtain a two-dimensional boron nitride slurry A; adding a coupling agent to the two-dimensional boron nitride slurry A to perform coupling modification to obtain a two-dimensional boron nitride slurry B; Adding glue to the two-dimensional boron nitride slurry B and mixing well to obtain a two-dimensional boron nitride slurry C; Pour the two-dimensional boron nitride slurry C into a tool, shake, and dry to obtain the boron nitride thermal conductive pad; The glue is polyurethane or vinyl silicone oil; The tooling includes a receiving cavity of a rectangular parallelepiped structure, and the receiving cavity is used to load the two-dimensional boron nitride slurry C; The frequency of the oscillation is 500 Hz-800 Hz, the power of the oscillation is 1.75 kW-1.95 kW, and the time of the oscillation is 10 min-30 min.

[0005] Furthermore, the solid content of the two-dimensional boron nitride slurry A is measured before adding the coupling agent to the two-dimensional boron nitride slurry A, and the mass ratio of the solid part in the two-dimensional boron nitride slurry A to the coupling agent is 1:(0.005-0.01).

[0006] Furthermore, the length of the accommodating cavity is 120mm-180mm, the width of the accommodating cavity is 80mm-120mm, the height of the accommodating cavity is 60mm-100mm, and the loading height of the two-dimensional boron nitride slurry C in the accommodating cavity is 20%-40% of the height of the accommodating cavity.

[0007] Furthermore, the solid content of the two-dimensional boron nitride slurry B is measured before adding the glue to the two-dimensional boron nitride slurry B. The mass ratio of the solid part in the two-dimensional boron nitride slurry B to the glue is (1-2):(8-9).

[0008] Furthermore, the coupling agent includes one of γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane and γ-aminopropyltrimethoxysilane.

[0009] Furthermore, the viscosity of the two-dimensional boron nitride slurry C is 1000 Pa·s-10000 Pa·s.

[0010] Furthermore, the drying temperature does not exceed 50° C., and the drying time is 24 hours to 48 hours.

[0011] Furthermore, the first solvent includes one of ethanol, isopropanol, and ethyl acetate, the mass ratio of the hexagonal boron nitride to the first solvent is 1:(3-5), and the sand milling time is 6h-36h.

[0012] A second aspect of the present invention provides a boron nitride thermally conductive gasket, which is prepared according to the above-mentioned preparation method.

[0013] A third aspect of the present invention provides application of the above-mentioned boron nitride thermally conductive gasket in the field of heat dissipation.

[0014] The beneficial effects of the present invention are as follows: the present invention improves the dispersibility and bonding strength of two-dimensional boron nitride in the glue matrix through coupling modification, increases the filling amount of two-dimensional boron nitride to enhance the heat conduction path, and reduces the hardness; in the present invention, the two-dimensional boron nitride is formed by vibration stacking with tooling to avoid interlayer adhesion defects of layer-by-layer stacking, thereby improving the thermal conductivity of the boron nitride thermal gasket as a whole. DETAILED DESCRIPTION

[0015] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content of the present invention record, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the application's appended claims.

[0016] An embodiment of the present invention provides a method for preparing a boron nitride thermally conductive gasket, comprising the following steps: Dispersing hexagonal boron nitride in a first solvent and sand-milling to obtain a two-dimensional boron nitride slurry A; adding a coupling agent to the two-dimensional boron nitride slurry A for coupling modification to obtain a two-dimensional boron nitride slurry B; Add glue to the two-dimensional boron nitride slurry B and mix well to obtain a two-dimensional boron nitride slurry C; Pour the two-dimensional boron nitride slurry C into the tooling, shake, and dry to obtain a boron nitride thermal conductive pad; Wherein, the first solvent is isopropyl alcohol (in some other embodiments, the first solvent may also be ethanol or ethyl acetate); The glue is polyurethane (in some other embodiments, the glue can also be vinyl silicone oil); The tooling includes a receiving cavity of a rectangular parallelepiped structure, and the receiving cavity is used to load the two-dimensional boron nitride slurry C; The oscillation frequency is 600 Hz, the oscillation power is 1.75 kW (in some other embodiments, the oscillation power is 1.75 kW-1.95 kW, for example, 1.80 kW, 1.85 kW, 1.90 kW, 1.95 kW), and the oscillation time is 30 min (in some other embodiments, the oscillation time can be 10 min-30 min, for example, 10 min, 15 min, 20 min).

[0017] The method for preparing a boron nitride thermal pad provided in this embodiment achieves high-quality boron nitride thermal pads through the synergistic effects of various steps. First, micron-sized hexagonal boron nitride is dispersed in isopropyl alcohol and sand-milled. The mechanical force of the sand-milling process refines the hexagonal boron nitride to the nanoscale, forming a two-dimensional boron nitride slurry A.

[0018] Next, a coupling agent is added to the two-dimensional boron nitride slurry A for coupling modification to obtain two-dimensional boron nitride slurry B. During this process, the coupling agent can effectively fill the pits and depressions on the surface of the two-dimensional boron nitride. This is mainly due to the strong adsorption and oil absorption properties of the two-dimensional boron nitride itself, which allows the coupling agent to fully fill its surface voids, thereby allowing the two-dimensional boron nitride to be better dispersed in the subsequently added glue, achieving a high filling of the two-dimensional boron nitride in the glue. This also reduces the hardness of the dried boron nitride thermal pad, facilitating subsequent cutting.

[0019] Subsequently, glue (polyurethane) as a matrix is ​​added to the two-dimensional boron nitride slurry B and mixed to obtain two-dimensional boron nitride slurry C. The addition of glue provides a matrix for subsequent molding.

[0020] Afterwards, the two-dimensional boron nitride slurry C is poured into the tooling and, through vibration (in this embodiment, the vibration is achieved by an oscillator), the two-dimensional boron nitride (the two-dimensional boron nitride is in sheet form) is made to lie flat in the horizontal direction. This step abandons the complex method of coating a thin film first and then stacking it layer by layer in the prior art. Instead, it utilizes the morphological properties of the two-dimensional boron nitride sheets to orient them along the plane within the tooling. This not only effectively solves the problem of dispersed orientation of the two-dimensional boron nitride, but this directional arrangement also significantly reduces the interfacial resistance in the heat conduction path, significantly improving the in-plane thermal conductivity of the gasket. It also eliminates the need for complex stacking processes and coating equipment, simplifying the production process, reducing process complexity, and avoiding the problems of weak bonding between layers and high hardness after stacking in the existing stacking process.

[0021] After shaking, the slurry in the tooling is dried to form a boron nitride thermal pad. This process gradually evaporates the solvent (isopropyl alcohol) in the slurry and cures the adhesive. Simultaneously, the functional groups in the coupling agent, which react with the adhesive, form stable chemical bonds with the polyurethane (or vinyl silicone oil) matrix. Compared to the existing stacking process, which relies on non-reactive acrylic resin pressure-sensitive adhesive to bond the various film layers, this significantly improves the structural stability of the cured material and avoids the structural collapse of the oriented boron nitride caused by the softening of acrylic resin pressure-sensitive adhesives under sustained high temperatures.

[0022] Finally, the boron nitride thermal pad can be cut into different thicknesses according to actual needs. Throughout the entire process, the coupled modified two-dimensional boron nitride and the glue form a more stable bonding system, which not only improves thermal conductivity but also ensures the mechanical properties and reliability of the boron nitride thermal pad. This achieves the coordinated optimization of material performance and production efficiency, and compared with existing technologies, it has improved product safety, stability, and process convenience.

[0023] Specifically, in this embodiment, the mass ratio of hexagonal boron nitride to isopropyl alcohol is 1:5. In some other embodiments, the mass ratio of hexagonal boron nitride to isopropyl alcohol can also be 1:(3-5), such as 1:3, 1:3.5, or 1:4.

[0024] If there is too much solvent (isopropyl alcohol), the concentration of boron nitride particles will be too low, the probability of collision between particles during sand milling will be reduced, and the mechanical force will be weakened, which will not only greatly reduce the refinement efficiency, but also increase the energy consumption and time of subsequent solvent volatilization. Excessive solvent may make the slurry too fluid during the oscillation process, resulting in uneven distribution of two-dimensional boron nitride. If there is too little solvent and the slurry concentration is too high, it will cause boron nitride particles to agglomerate, and the force cannot be evenly distributed during sand milling. Some particles are difficult to be fully ground, forming a mixed layer of coarse and fine. At the same time, the high-concentration slurry has poor fluidity, which will aggravate the internal wear of the sand mill and even destroy the crystal structure of boron nitride due to local friction overheating, affecting the final thermal conductivity. In the subsequent oscillation process, the high-concentration slurry has insufficient fluidity, which will make it difficult for the two-dimensional boron nitride flakes to move freely under the action of the oscillation and cannot fully lie flat in the horizontal direction. Local accumulation or orientation disorder is prone to occur, resulting in uneven arrangement of the flakes, thereby affecting the thermal conductivity.

[0025] Specifically, the sanding time in this embodiment is 24 hours. In some other embodiments, the sanding time can also be 6 hours to 36 hours, such as 6 hours, 12 hours, 20 hours, 30 hours, and 36 hours.

[0026] If the sanding time is too short, the hexagonal boron nitride cannot be fully refined, and larger particles are likely to remain, resulting in uneven thickness of the two-dimensional boron nitride layer, which is difficult to disperse evenly in the glue later, affecting the continuity of the thermal conductivity path; if the sanding time is too long, excessive mechanical force will destroy the two-dimensional layer structure of the boron nitride, causing the layer to break or the structure to collapse, which will reduce its thermal conductivity. At the same time, too many impurities may be introduced due to long-term grinding, affecting the stability of the slurry.

[0027] Furthermore, the solid content of the two-dimensional boron nitride slurry A was measured before adding the coupling agent to the two-dimensional boron nitride slurry A. The mass ratio of the solid part in the two-dimensional boron nitride slurry A to the coupling agent was 1:(0.005-0.01).

[0028] Specifically, the solid content of the two-dimensional boron nitride slurry A in this embodiment is determined by taking an appropriate amount of two-dimensional boron nitride slurry A, weighing it, recording the weight m1, and then drying it, recording the weight m2. The solid content is calculated (solid content calculation formula: solid content = m2 / m1·100%). In this embodiment, the mass ratio of the solid portion to the coupling agent in the two-dimensional boron nitride slurry A is 1:0.01. In other embodiments, the mass ratio of the solid portion to the coupling agent in the two-dimensional boron nitride slurry A can also be 1:(0.005-0.01), for example, 1:0.005, 1:0.006, or 1:0.008.

[0029] When the amount of coupling agent is insufficient, the pits and gaps on the surface of the two-dimensional boron nitride cannot be fully filled, resulting in incomplete modification of the two-dimensional boron nitride surface, and thus the inability to achieve a high filling of the two-dimensional boron nitride in the glue; while an excessive amount of coupling agent will form an excessively thick coating layer on the surface of the two-dimensional boron nitride, hindering the direct contact between the two-position boron nitrides. The coupling agent itself has poor thermal conductivity, weakening the connectivity of the thermal network and the thermal conductivity of the boron nitride thermal gasket. In addition, the free excess coupling agent will interact adversely with the subsequently added glue, resulting in a decrease in the adhesive strength of the glue, and ultimately affecting the mechanical properties of the boron nitride thermal gasket.

[0030] Preferably, the coupling agent in this embodiment is γ-methacryloxypropyltrimethoxysilane, specifically Shin-Etsu KBM-503 from Japan.

[0031] When the coupling agent is γ-methacryloxypropyltrimethoxysilane, the trimethoxysilyl groups in its molecular structure can hydrolyze to generate silanol groups, which then undergo condensation reactions with the hydroxyl groups on the surface of the 2D BN to form stable covalent bonds. This significantly enhances the anchoring strength of the coupling agent to the BN surface and prevents the modified layer from falling off. Furthermore, the methacryloxy functional groups in the coupling agent exhibit excellent reactivity with the unsaturated double bonds in the polyurethane (or vinyl silicone oil) matrix. During the curing process, they form chemical crosslinks through free radical polymerization, further strengthening the interfacial bonding between the BN and the adhesive matrix. Compared to conventional coupling agents, this coupling agent can more effectively reduce interfacial thermal resistance and improve the continuity of the thermal conductivity path. Furthermore, the hydrophobicity of the molecular chain segments of the coupling agent further optimizes the hydrophobicity of the BN surface, reducing the impact of moisture on the material structure. Its improved compatibility with silicone systems reduces agglomeration of the modified slurry and improves the dispersion uniformity and loading of the 2D BN in the adhesive, laying a good foundation for subsequent oriented alignment.

[0032] Furthermore, the solid content of the two-dimensional boron nitride slurry B was measured before adding glue to the two-dimensional boron nitride slurry B. The mass ratio of the solid part in the two-dimensional boron nitride slurry B to the glue was (1-2):(8-9).

[0033] Specifically, the solid content of the two-dimensional boron nitride slurry B in this embodiment is determined in the same manner as the solid content of the two-dimensional boron nitride slurry A. In this embodiment, the mass ratio of the solid portion to the glue in the two-dimensional boron nitride slurry B is 1:9.

[0034] The core function of glue as a matrix is ​​to form a continuous phase through solidification, bonding the stacked and shaken two-dimensional boron nitride into a whole. Using too little glue will result in the matrix not being able to fully wrap the two-dimensional boron nitride. The two-dimensional boron nitride will agglomerate due to the high surface energy, making it difficult to stack flatly during the shaking process. The material structure will be loose after solidification, affecting the mechanical and thermal properties. If too much glue is used, the solvent will be wrapped by a large amount of colloid, the evaporation rate will slow down, and this may lead to incomplete curing. Residual solvent will reduce the chemical stability of the material, and the thickness of the boron nitride thermal pad obtained after curing may exceed expectations. Moreover, due to the excessive amount of colloid, it is easy to cause rough edges and reduced dimensional accuracy during cutting due to excessive softness.

[0035] Specifically, the viscosity of the two-dimensional boron nitride slurry C in this embodiment is 5000 Pa·s. In some other embodiments, the viscosity of the two-dimensional boron nitride slurry C can also be 1000 Pa·s-10000 Pa·s, for example, 1000 Pa·s, 3000 Pa·s, 8000 Pa·s, and 10000 Pa·s.

[0036] When the slurry viscosity is too low, the thin slurry system will make the two-dimensional boron nitride easily settle due to gravity and form stratification. The oscillation effect is difficult to offset the random orientation brought by Brownian motion, resulting in a significant reduction in the orientation degree of the two-dimensional boron nitride. In addition, the low-viscosity slurry is prone to violent turbulence under the action of oscillation, which will disperse the two-dimensional boron nitride that has been initially stacked, resulting in a disordered distribution, and ultimately affecting the uniformity of the performance of the boron nitride thermal gasket; when the slurry viscosity is too high, the two-dimensional boron nitride will be hindered during oscillation, and it will be difficult to adjust its posture under the action of oscillation to achieve a horizontal "lying flat" orientation. It may even form disordered accumulation due to local jamming. In addition, the poor fluidity of the slurry makes it difficult to spread evenly, which ultimately leads to a chaotic internal structure of the boron nitride thermal gasket and a decrease in performance consistency. Specifically, in this embodiment, the length of the accommodating cavity is 150 mm, the width of the accommodating cavity is 120 mm, the height of the accommodating cavity is 80 mm, and the loading height of the two-dimensional boron nitride slurry C in the accommodating cavity is 20 mm (25% of the height of the accommodating cavity).

[0037] The chamber dimensions and loading capacity of this embodiment provide ample buffer space for the slurry during oscillation, effectively preventing fluctuations caused by vibration from causing the slurry to overflow the tooling, ensuring a stable total slurry volume within the system and reducing material loss and dimensional deviation. Furthermore, the ample space reduces the boundary constraints of the slurry during oscillation, allowing the 2D boron nitride to more freely adjust its posture under the action of oscillation, reducing localized squeezing or accumulation caused by confined space and facilitating uniform, horizontal stacking of the 2D boron nitride.

[0038] Furthermore, in this embodiment, the bottom and side walls of the accommodating cavity are protected by a release film to prevent the cured boron nitride thermal gasket from adhering to the accommodating cavity due to excessive bonding force, thereby ensuring a smooth demolding process and reducing edge damage or structural deformation.

[0039] Specifically, the drying temperature in this embodiment is 50°C (in some other embodiments, the drying temperature does not exceed 50°C), and the drying time is 24 hours (in some other embodiments, the drying time can be 24 hours to 48 hours, such as 28 hours, 30 hours, 36 hours, or 48 hours).

[0040] In this embodiment, slow, low-temperature drying allows the solvent to evaporate evenly and orderly, preventing the formation of bubbles or pores in the glue matrix caused by local pressure differences caused by rapid solvent evaporation. This prevents the material from developing a loose, "beehive"-like structure and ensures that the two-dimensional boron nitride remains in a stable, horizontally stacked state before the glue cures. Furthermore, slow drying provides ample time for the glue matrix to cure, making the curing process more uniform and avoiding uneven curing caused by excessive or insufficient solvent residue, thereby ensuring the consistency of the final boron nitride thermal pad's performance.

[0041] In a comparative example, the preparation of a boron nitride gasket includes the following steps: Disperse hexagonal boron nitride in isopropyl alcohol (the mass ratio of hexagonal boron nitride to isopropyl alcohol is 1:5) and sand grind (sand grinding time is 24 hours) to obtain two-dimensional boron nitride slurry A; Adding acrylic resin (acrylic resin as a matrix) to the two-dimensional boron nitride slurry A and mixing well to obtain the two-dimensional boron nitride slurry B; The two-dimensional boron nitride slurry B is coated multiple times (each coating thickness is 80 μm), and dried to obtain multiple boron nitride thermal conductive films; Multiple boron nitride thermal conductive films are stacked, hot-pressed, and cut along the vertical direction to obtain boron nitride gaskets.

[0042] Thermal conductivity and hardness tests were performed on the boron nitride thermally conductive gasket prepared in the example and the boron nitride gasket prepared in the comparative example. The thermal conductivity test was performed according to the standard ASTM D 5470-17, and the hardness test was performed according to the standard ASTM D2240.

[0043] The results of the test showed that the thermal conductivity of the boron nitride thermal conductive gasket prepared in the embodiment was 28.7 W / (m·℃) and the hardness was 62 shore 00; the thermal conductivity of the boron nitride gasket prepared in the comparative example was 14.3 W / (m·℃) and the hardness was 95 shore A.

[0044] In this specification, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, features specified as "first" or "second" may explicitly or implicitly include at least one of such features.

[0045] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and supplements without departing from the method of the present invention. These improvements and supplements should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a boron nitride thermally conductive gasket, characterized in that: The following steps are involved: Dispersing hexagonal boron nitride in a first solvent and sand-milling to obtain a two-dimensional boron nitride slurry A; adding a coupling agent to the two-dimensional boron nitride slurry A to perform coupling modification to obtain a two-dimensional boron nitride slurry B; Adding glue to the two-dimensional boron nitride slurry B and mixing well to obtain a two-dimensional boron nitride slurry C; Pour the two-dimensional boron nitride slurry C into a tool, shake, and dry to obtain the boron nitride thermal conductive pad; The glue is polyurethane or vinyl silicone oil; The tooling includes a receiving cavity of a rectangular parallelepiped structure, and the receiving cavity is used to load the two-dimensional boron nitride slurry C; The frequency of the oscillation is 500 Hz-800 Hz, the power of the oscillation is 1.75 kW-1.95 kW, and the time of the oscillation is 10 min-30 min.

2. The method for preparing a boron nitride thermally conductive pad according to claim 1, wherein: Before adding the coupling agent to the two-dimensional boron nitride slurry A, the solid content of the two-dimensional boron nitride slurry A is measured. The mass ratio of the solid part in the two-dimensional boron nitride slurry A to the coupling agent is 1:(0.005-0.01).

3. The method for preparing a boron nitride thermally conductive gasket according to claim 2, wherein: The coupling agent includes one of γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane and γ-aminopropyltrimethoxysilane.

4. The method for preparing a boron nitride thermally conductive pad according to claim 1, wherein: The length of the accommodating cavity is 120mm-180mm, the width of the accommodating cavity is 80mm-120mm, the height of the accommodating cavity is 60mm-100mm, and the loading height of the two-dimensional boron nitride slurry C in the accommodating cavity is 20%-40% of the height of the accommodating cavity.

5. The method for preparing a boron nitride thermally conductive gasket according to claim 1, wherein: Before adding the glue to the two-dimensional boron nitride slurry B, the solid content of the two-dimensional boron nitride slurry B is measured. The mass ratio of the solid part in the two-dimensional boron nitride slurry B to the glue is (1-2):(8-9).

6. The method for preparing a boron nitride thermally conductive gasket according to claim 1, wherein: The viscosity of the two-dimensional boron nitride slurry C is 1000 Pa·s-10000 Pa·s.

7. The method for preparing a boron nitride thermally conductive gasket according to claim 1, wherein: The drying temperature does not exceed 50° C., and the drying time is 24 hours to 48 hours.

8. The method for preparing a boron nitride thermally conductive gasket according to claim 1, wherein: The first solvent includes one of ethanol, isopropanol, and ethyl acetate. The mass ratio of the hexagonal boron nitride to the first solvent is 1:(3-5). The sand milling time is 6 hours to 36 hours.

9. A boron nitride thermally conductive pad, characterized in that: The boron nitride thermally conductive gasket is prepared according to the preparation method according to any one of claims 1 to 8.

10. Use of the boron nitride thermally conductive pad according to claim 9 in the field of heat dissipation.