Low-density anti-settling heat-conducting pouring sealant and preparation method thereof

Abstract

The invention belongs to the technical field of pouring sealants, and particularly discloses a low-density anti-settling heat-conducting pouring sealant and a preparation method thereof. The pouring sealant comprises a component A and a component B, the component A comprises vinyl silicone oil, silica powder, modified hollow glass beads, nano calcium carbonate and a platinum catalyst, and the component B comprises vinyl silicone oil, end chain hydrogen-containing silicone oil, side chain hydrogen-containing silicone oil, silica powder, modified hollow glass beads, nano calcium carbonate and ethynyl cyclohexanol. By adopting the modified hollow glass beads coated with the graphene oxide, the heat-conducting property of the pouring sealant is improved, meanwhile, the pouring sealant has the effects of light weight and mechanical enhancement, the technical problem that heat conduction, insulation, light weight and sedimentation of a traditional pouring sealant are difficult to consider at the same time is solved, and the pouring sealant is particularly suitable for the field of precision electronics with efficient heat dissipation and light protection.

Description

Technical Field

[0001] This invention relates to the field of potting compound technology, specifically to a low-density anti-settling thermally conductive potting compound and its preparation method. Background Technology

[0002] As electronic devices evolve towards higher power density and lighter weight, stringent requirements are being placed on the overall performance of thermally conductive potting compounds. The core challenge currently facing the technology lies in two aspects: using high-density thermally conductive fillers (such as alumina) leads to excessive product weight, making it difficult to meet lightweight requirements; while using hollow glass microspheres to reduce density presents two major technical challenges: poor thermal conductivity and significant density difference with the matrix, resulting in deterioration of thermal conductivity and filler sedimentation.

[0003] To reduce density, hollow glass microspheres are often used as lightweight fillers in existing technologies. However, hollow glass microspheres have extremely low thermal conductivity, and their large-scale introduction can severely degrade the thermally conductive network of the potting compound, leading to a decrease in thermal conductivity. For thermally conductive potting compounds with high filler content, filler sedimentation is a long-standing and significantly detrimental technical problem. Sedimentation causes uneven distribution of the thermally conductive filler in three-dimensional space, and heat cannot be effectively dissipated in areas with insufficient filler, which is fatal for high-reliability applications such as electronic devices.

[0004] In view of this, the present invention achieves a synergistic improvement in thermal conductivity and anti-settling properties by using graphene oxide-coated hollow glass microspheres combined with nano-calcium carbonate, providing a new solution for the development of high-performance low-density potting compounds. Summary of the Invention

[0005] The main objective of this invention is to provide a low-density, anti-settling, thermally conductive potting compound and its preparation method, thereby addressing the problems mentioned in the background art. This invention utilizes graphene oxide to construct a three-dimensional thermally conductive network in situ on the surface of microspheres, effectively compensating for the thermal conductivity defects of hollow structures. Nano-calcium carbonate, through steric hindrance and interface regulation, significantly improves the dispersion stability of the filler, inhibiting sedimentation and caking. This successfully achieves synergistic optimization of low density, high thermal conductivity, and long-term storage stability, providing a new path for the development of high-performance, lightweight thermally conductive potting compounds.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A low-density, anti-settling, thermally conductive potting compound comprises component A and component B. Component A comprises the following raw materials in parts by weight: 250-350 parts vinyl silicone oil, 400-550 parts silica powder, 100-550 parts modified hollow glass microspheres, 30-50 parts nano-calcium carbonate, and 0.2-0.7 parts platinum catalyst. Component B comprises the following raw materials in parts by weight: 50-170 parts vinyl silicone oil, 150-300 parts end-chain hydrogen-containing silicone oil, 10-20 parts side-chain hydrogen-containing silicone oil, 400-550 parts silica powder, 100-550 parts modified hollow glass microspheres, 30-50 parts nano-calcium carbonate, and 0.01-0.03 parts ethynylcyclohexanol.

[0007] Preferably, the vinyl silicone oil is a double-ended vinyl silicone oil with a viscosity of 25-2000 mPa·s; the silicon micropowder is crystalline silicon micropowder with an average particle size of 1-50 μm; and the modified hollow glass microspheres have a particle size of 5-50 μm.

[0008] Preferably, the graphene oxide morphology is selected from at least one of sheet-like, film-like, quantum dot, nanoribbon, or three-dimensional forms; the platinum catalyst is selected from caster catalysts.

[0009] Preferably, the hydrogen content of the end-chain hydrogen-containing silicone oil is 0.7-0.9%, more preferably 0.81%; the hydrogen content of the side-chain hydrogen-containing silicone oil is 0.06-0.09%, more preferably 0.07%.

[0010] Preferably, the nano-calcium carbonate is nano-calcium carbonate that has undergone hydrophobic modification. The modification method is to react stearic acid with sodium hydroxide to obtain sodium stearate modifier, and then mix and modify it with nano-calcium carbonate before drying or surface treatment with silane coupling agent.

[0011] Preferably, the coupling agent is one or a combination of several of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, vinyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and vinyltrimethoxysilane.

[0012] More preferably, the coupling agent is N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and γ-aminopropyltriethoxysilane.

[0013] Preferably, the modified hollow glass microspheres are graphene oxide-coated modified hollow glass microspheres, and the preparation method is as follows: (1) Hollow glass microspheres HGM were added to a mixed solution of H2SO4 / H2O2, soaked in a water bath for 30 min, washed with water until neutral and dried to obtain hydroxylated HGM; (2) Dissolve the aminosilane coupling agent in a mixed solvent of ethanol and water to form a mixed solution; add hydroxylated HGM to the mixed solution and stir for 40 min to obtain aminolated HGM; (3) Graphene oxide (GO) was dispersed in MES buffer to form GO buffer, and an activation reagent was added and ultrasonic treatment was performed to obtain an activated GO solution. (4) Add the aminated HGM to the activated GO solution, stir and react for 24-48 h, then filter, wash and dry to obtain graphene oxide-coated composite microspheres (GO@HGM).

[0014] Preferably, in step (1), the volume ratio of concentrated sulfuric acid to hydrogen peroxide is 6-8:2-4, the volume fraction of concentrated sulfuric acid is 98wt%, the volume fraction of hydrogen peroxide is 30wt%, and the mass percentage of hollow glass microspheres is 10%.

[0015] Preferably, in step (2), the volume ratio of ethanol to water is 1:1, and the amount of aminosilane coupling agent is 2-8% of the mass of HGM.

[0016] Preferably, the graphene oxide is selected from at least one of sheet-like, film-like, quantum dot, nanoribbon, and three-dimensional forms.

[0017] Preferably, in step (3), the carboxyl content of graphene oxide is 8-12%, the pH of the MES buffer is 5.8-6.0, and the concentration is 1 mol / L; the dispersion concentration of the activating reagent is 1-3 mg / ml, and the dispersion concentration of the activated GO solution is 0.5-2 mg / ml.

[0018] Preferably, the activating agent is selected from 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide or N-hydroxysuccinimide.

[0019] A second aspect of the present invention provides a method for preparing the low-density anti-settling thermally conductive potting compound, comprising the following steps: S1. Vinyl silicone oil, silica powder, modified hollow glass microspheres, nano-calcium carbonate and platinum catalyst are mixed in a planetary mixer under normal pressure, and then mixed under vacuum conditions to obtain component A. S2. Vinyl silicone oil, end-chain hydrogen-containing silicone oil, side-chain hydrogen-containing silicone oil, silicon micro powder, modified hollow glass microspheres, nano-calcium carbonate and ethynylcyclohexanol are mixed in a planetary mixer under normal pressure, and then mixed under vacuum conditions to obtain component B. S3. Mix components A and B according to the mass ratio to obtain the thermally conductive potting compound.

[0020] The beneficial effects of this invention are as follows: 1. Low density: This invention uses hollow glass microspheres as a lightweight filler (0.15-0.60 g / cm³).3 This significantly reduces the overall density of the potting compound; at the same time, by loading graphene oxide onto its surface, a three-dimensional thermally conductive network is constructed in situ, achieving a lightweight design without sacrificing thermal conductivity, thus giving the material both low density and high thermal conductivity.

[0021] 2. Excellent anti-settling properties: Nano-calcium carbonate effectively inhibits filler agglomeration through steric hindrance, and together with graphite oxide, its layered structure enhances the dispersibility of the filler. The two work synergistically to avoid problems such as sedimentation and caking from the root, ensuring the stability of material performance.

[0022] 3. Excellent mechanical properties and flame retardancy: The reinforcing effect of nano-calcium carbonate and the interfacial enhancement effect of graphene oxide synergistically improve the toughness and strength of the colloid; while hollow glass microspheres are inorganic flame-retardant materials, which, combined with the high-temperature charring effect of graphene oxide, work together to exert flame retardant effects, enabling the potting compound to meet the UL94 V0 flame retardant standard. Detailed Implementation

[0023] The present invention will be further described below with reference to specific embodiments. In the following embodiments, the platinum catalyst is selected from caster catalysts, the vinyl mass fraction of the vinyl silicone oil is 3%, the hydrogen content of the end-chain hydrogen-containing silicone oil is 0.81%, and the hydrogen content of the side-chain hydrogen-containing silicone oil is 0.07%. The modified hollow glass microspheres were prepared as follows: (1) Add HGM to a mixed solution of H2SO4 / H2O2 with a volume ratio of 7:3, so that the mass percentage of HGM is 10%; after soaking the reaction system in a water bath at 90℃ for 30 min, wash it repeatedly with deionized water until neutral and dry it at 80℃ to obtain hydroxylated HGM. (2) Weigh out 5% GO mass fraction of aminosilane coupling agent and dissolve it in a mixed solvent of ethanol and water with a volume ratio of 1:1 to form a mixed solution; add the hydroxylated HGM from step (1) to the mixed solution and stir for 40 min to obtain aminolated HGM. (3) Disperse GO in MES buffer to form a GO buffer with a dispersion concentration of 2 mg / ml, add 3 mg / ml activation reagent, and sonicate for 2 h to obtain activated GO solution; (4) Add the aminated HGM from step (2) to the activated GO solution from step (3), stir and react for 26 h, filter and wash with MES buffer, ethanol and deionized water in sequence, and dry under vacuum at 60 °C to obtain graphene oxide-coated composite microspheres (GO@HGM).

[0024] Example 1: This embodiment provides a low-density anti-settling thermally conductive potting compound, comprising component A and component B. Component A comprises the following raw materials in parts by weight: 350 parts vinyl silicone oil, 400 parts silica powder, 100 parts modified hollow glass microspheres, 30 parts nano-calcium carbonate, and 0.5 parts platinum catalyst. Component B comprises the following raw materials in parts by weight: 170 parts vinyl silicone oil, 300 parts end-chain hydrogen-containing silicone oil, 15 parts side-chain hydrogen-containing silicone oil, 400 parts silica powder, 100 parts modified hollow glass microspheres, 30 parts nano-calcium carbonate, and 0.02 parts ethynylcyclohexanol. The preparation method of this low-density anti-settling thermally conductive potting compound includes the following steps: S1. Vinyl silicone oil, silica powder, modified hollow glass microspheres, nano-calcium carbonate and platinum catalyst are mixed in a planetary mixer under normal pressure, and then mixed under vacuum conditions to obtain component A. S2. Vinyl silicone oil, end-chain hydrogen-containing silicone oil, side-chain hydrogen-containing silicone oil, silicon micro powder, modified hollow glass microspheres, nano-calcium carbonate and ethynylcyclohexanol are mixed in a planetary mixer under normal pressure, and then mixed under vacuum conditions to obtain component B. S3. Mix components A and B in a mass ratio of 1:1 to obtain the thermally conductive potting compound.

[0025] Example 2: This embodiment provides a low-density anti-settling thermally conductive potting compound, comprising component A and component B. Component A comprises the following raw materials in parts by weight: 300 parts vinyl silicone oil, 450 parts silica powder, 100 parts modified hollow glass microspheres, 35 parts nano-calcium carbonate, and 0.5 parts platinum catalyst. Component B comprises the following raw materials in parts by weight: 100 parts vinyl silicone oil, 200 parts end-chain hydrogen-containing silicone oil, 15 parts side-chain hydrogen-containing silicone oil, 450 parts silica powder, 100 parts modified hollow glass microspheres, 35 parts nano-calcium carbonate, and 0.02 parts ethynylcyclohexanol.

[0026] The preparation method of this low-density anti-settling thermally conductive potting compound includes the following steps: S1. Vinyl silicone oil, silica powder, modified hollow glass microspheres, nano-calcium carbonate and platinum catalyst are mixed in a planetary mixer under normal pressure, and then mixed under vacuum conditions to obtain component A. S2. Vinyl silicone oil, end-chain hydrogen-containing silicone oil, side-chain hydrogen-containing silicone oil, silicon micro powder, modified hollow glass microspheres, nano-calcium carbonate and ethynylcyclohexanol are mixed in a planetary mixer under normal pressure, and then mixed under vacuum conditions to obtain component B. S3. Mix components A and B in a mass ratio of 1:1 to obtain the thermally conductive potting compound.

[0027] Example 3: This embodiment provides a low-density anti-settling thermally conductive potting compound, comprising component A and component B. Component A comprises the following raw materials in parts by weight: 300 parts vinyl silicone oil, 450 parts silica powder, 400 parts modified hollow glass microspheres, 50 parts nano-calcium carbonate, and 0.5 parts platinum catalyst. Component B comprises the following raw materials in parts by weight: 100 parts vinyl silicone oil, 200 parts end-chain hydrogen-containing silicone oil, 15 parts side-chain hydrogen-containing silicone oil, 450 parts silica powder, 400 parts modified hollow glass microspheres, 50 parts nano-calcium carbonate, and 0.02 parts ethynylcyclohexanol.

[0028] The preparation method of this low-density anti-settling thermally conductive potting compound includes the following steps: S1. Vinyl silicone oil, silica powder, modified hollow glass microspheres, nano-calcium carbonate and platinum catalyst are mixed in a planetary mixer under normal pressure, and then mixed under vacuum conditions to obtain component A. S2. Vinyl silicone oil, end-chain hydrogen-containing silicone oil, side-chain hydrogen-containing silicone oil, silicon micro powder, modified hollow glass microspheres, nano-calcium carbonate and ethynylcyclohexanol are mixed in a planetary mixer under normal pressure, and then mixed under vacuum conditions to obtain component B. S3. Mix components A and B in a mass ratio of 1:1 to obtain the thermally conductive potting compound.

[0029] Example 4: This embodiment provides a low-density anti-settling thermally conductive potting compound, comprising component A and component B. Component A comprises the following raw materials in parts by weight: 300 parts vinyl silicone oil, 450 parts silica powder, 400 parts modified hollow glass microspheres, 35 parts nano-calcium carbonate, and 0.5 parts platinum catalyst. Component B comprises the following raw materials in parts by weight: 100 parts vinyl silicone oil, 200 parts end-chain hydrogen-containing silicone oil, 15 parts side-chain hydrogen-containing silicone oil, 450 parts silica powder, 400 parts modified hollow glass microspheres, 35 parts nano-calcium carbonate, and 0.02 parts ethynylcyclohexanol.

[0030] The preparation method of this low-density anti-settling thermally conductive potting compound includes the following steps: S1. Vinyl silicone oil, silica powder, modified hollow glass microspheres, nano-calcium carbonate and platinum catalyst are mixed in a planetary mixer under normal pressure, and then mixed under vacuum conditions to obtain component A. S2. Vinyl silicone oil, end-chain hydrogen-containing silicone oil, side-chain hydrogen-containing silicone oil, silicon micro powder, modified hollow glass microspheres, nano-calcium carbonate and ethynylcyclohexanol are mixed in a planetary mixer under normal pressure, and then mixed under vacuum conditions to obtain component B. S3. Mix components A and B in a mass ratio of 1:1 to obtain the thermally conductive potting compound.

[0031] Comparative Example 1: This comparative example provides a low-density anti-settling thermally conductive potting compound, comprising component A and component B. Component A comprises the following raw materials in parts by weight: 250 parts vinyl silicone oil, 550 parts silica powder, 300 parts modified hollow glass microspheres, 50 parts nano-calcium carbonate, and 0.5 parts platinum catalyst. Component B comprises the following raw materials in parts by weight: 150 parts end-chain hydrogen-containing silicone oil, 10 parts side-chain hydrogen-containing silicone oil, 550 parts silica powder, 550 parts modified hollow glass microspheres, 30 parts nano-calcium carbonate, and 0.02 parts ethynylcyclohexanol.

[0032] The preparation method of this low-density anti-settling thermally conductive potting compound is the same as in Example 4.

[0033] Comparative Example 2: This comparative example provides a low-density anti-settling thermally conductive potting compound, comprising component A and component B. Component A comprises the following raw materials in parts by weight: 300 parts vinyl silicone oil, 450 parts silica powder, 400 parts modified hollow glass microspheres, 35 parts nano-calcium carbonate, and 0.5 parts platinum catalyst. Component B comprises the following raw materials in parts by weight: 100 parts vinyl silicone oil, 200 parts end-chain hydrogen-containing silicone oil, 15 parts side-chain hydrogen-containing silicone oil, 450 parts silica powder, 400 parts sheet-like graphene oxide, 35 parts nano-calcium carbonate, and 0.02 parts ethynylcyclohexanol.

[0034] The preparation method of this low-density anti-settling thermally conductive potting compound is the same as in Example 4.

[0035] Comparative Example 3: This invention provides a low-density, anti-settling, thermally conductive potting compound, comprising component A and component B. Component A comprises the following raw materials in parts by weight: 300 parts vinyl silicone oil, 450 parts silica powder, 400 parts modified hollow glass microspheres, and 0.5 parts platinum catalyst. Component B comprises the following raw materials in parts by weight: 100 parts vinyl silicone oil, 200 parts end-chain hydrogen-containing silicone oil, 15 parts side-chain hydrogen-containing silicone oil, 450 parts silica powder, 400 parts modified hollow glass microspheres, and 0.02 parts ethynylcyclohexanol.

[0036] The preparation method of this low-density anti-settling thermally conductive potting compound is the same as in Example 4.

[0037] Comparative Example 4: This comparative example provides a low-density anti-settling thermally conductive potting compound, comprising component A and component B. Component A comprises the following raw materials in parts by weight: 300 parts vinyl silicone oil, 450 parts silica powder, 400 parts modified hollow glass microspheres, 35 parts nano-calcium carbonate, and 0.5 parts platinum catalyst. Component B comprises the following raw materials in parts by weight: 100 parts vinyl silicone oil, 200 parts end-chain hydrogen-containing silicone oil, 15 parts side-chain hydrogen-containing silicone oil, 450 parts silica powder, 400 parts ordinary hollow glass microspheres, 35 parts nano-calcium carbonate, and 0.02 parts ethynylcyclohexanol.

[0038] The preparation method of this low-density anti-settling thermally conductive potting compound is the same as in Example 4.

[0039] The performance of the potting compounds prepared in Examples 1-4 and Comparative Examples 1-4 was measured, and the results are shown in Table 1.

[0040] Table 1

[0041] As shown in Table 1, Examples 1-4 all used modified hollow glass microspheres and nano-calcium carbonate as a synergistic filler system, combined with appropriate amounts of vinyl silicone oil and hydrogen-containing silicone oil, so that the product maintained a low density (1.20-1.57 g / cm³). 3 At the same time, it has good thermal conductivity (1.2-1.5W / (m·K)), suitable viscosity (1770-3700mPa·s) and excellent anti-settling properties (no lower layer caking, controllable oil-powder separation), and all of them reach the flame retardant level, among which Example 4 has the best performance.

[0042] As can be seen from the examples and comparative examples, Comparative Example 1, due to its low amount of vinyl silicone oil and high total filler content, resulted in a viscosity as high as 9780 mPa·s and poor anti-settling properties, indicating that an imbalance in the raw material ratio affects workability and stability. Comparative Example 2, although the introduction of sheet-like graphene oxide improved the thermal conductivity, the viscosity increased to 13460 mPa·s, indicating that loading graphene oxide onto hollow glass microspheres can effectively prevent a surge in viscosity and ensure processability. Comparative Example 3, lacking nano-calcium carbonate, showed obvious lower layer caking after curing, indicating that nano-calcium carbonate can improve the dispersibility of fillers and prevent sedimentation and caking. Comparative Example 4, using ordinary hollow glass microspheres instead of modified glass microspheres, resulted in a sharp decrease in thermal conductivity (0.7 W / (m·K)), indicating that modified hollow glass microspheres with surface-loaded graphene oxide are crucial for constructing efficient thermal conduction pathways.

[0043] In summary, the potting compound of the present invention achieves a balance in viscosity, thermal conductivity, density, and stability by optimizing the powder ratio and adding modified hollow glass microspheres and nano-calcium carbonate, providing a practical technical solution for electronic packaging materials with high thermal conductivity, lightweight, and high reliability.

[0044] The above embodiments are merely preferred technical solutions of the present invention and should not be considered as limitations on the present invention. The scope of protection of the present invention should be limited to the technical solutions described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A low-density, anti-settling, thermally conductive potting compound, characterized in that: The product comprises component A and component B. Component A comprises the following raw materials in parts by weight: 250-350 parts vinyl silicone oil, 400-550 parts silica powder, 100-550 parts modified hollow glass microspheres, 30-50 parts nano-calcium carbonate, and 0.2-0.7 parts platinum catalyst. Component B comprises the following raw materials in parts by weight: 50-170 parts vinyl silicone oil, 150-300 parts end-chain hydrogen-containing silicone oil, 10-20 parts side-chain hydrogen-containing silicone oil, 400-550 parts silica powder, 100-550 parts modified hollow glass microspheres, 30-50 parts nano-calcium carbonate, and 0.01-0.03 parts ethynylcyclohexanol.

2. The low-density anti-settling thermally conductive potting compound according to claim 1, characterized in that, The vinyl silicone oil is a double-ended vinyl silicone oil with a viscosity of 50-2000 mPa·s; the silicon micropowder is crystalline silicon micropowder with an average particle size of 1-50 μm; and the hollow glass microspheres have a particle size of 5-50 μm.

3. The low-density anti-settling thermally conductive potting compound according to claim 1, characterized in that, The graphene oxide morphology is selected from at least one of sheet-like, film-like, quantum dot, nanoribbon, or three-dimensional forms; the platinum catalyst is selected from caster catalysts.

4. The low-density anti-settling thermally conductive potting compound according to claim 1, characterized in that, The nano-calcium carbonate is a nano-calcium carbonate that has undergone hydrophobic modification. The modification method is to react stearic acid with sodium hydroxide to obtain sodium stearate modifier, and then mix it with nano-calcium carbonate for modification and drying, or to use a silane coupling agent for surface treatment.

5. The low-density anti-settling thermally conductive potting compound according to claim 4, characterized in that, The coupling agent is one or a combination of several of the following: γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, vinyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and vinyltrimethoxysilane.

6. The low-density anti-settling thermally conductive potting compound according to claim 1, characterized in that, The modified hollow glass microspheres are graphene oxide-coated modified hollow glass microspheres, and the preparation method is as follows: (1) Hollow glass microspheres HGM were added to a mixed solution of H2SO4 / H2O2, soaked in a water bath, washed with water until neutral and dried to obtain hydroxylated HGM. (2) Dissolve the aminosilane coupling agent in a mixed solvent of ethanol and water to form a mixed solution; add the hydroxylated HGM to the mixed solution and stir until homogeneous to obtain the aminolated HGM; (3) Graphene oxide (GO) was dispersed in MES buffer to form GO buffer, and an activation reagent was added and ultrasonic treatment was performed to obtain an activated GO solution. (4) Add the aminated HGM to the activated GO solution, stir and react for 24-48 h, then filter, wash and dry to obtain composite microspheres coated with graphene oxide.

7. The low-density anti-settling thermally conductive potting compound according to claim 6, characterized in that, In step (1), the volume ratio of concentrated sulfuric acid to hydrogen peroxide is 6-8:2-4, the volume fraction of concentrated sulfuric acid is 98wt%, and the volume fraction of hydrogen peroxide is 30wt%; the mass percentage of hollow glass microspheres is 10%.

8. The low-density anti-settling thermally conductive potting compound according to claim 6, characterized in that, In step (2), the volume ratio of ethanol to water is 1:1, and the amount of aminosilane coupling agent used is 2-8% of the mass of HGM.

9. The low-density anti-settling thermally conductive potting compound according to claim 6, characterized in that, The graphene oxide described in step (3) has a carboxyl content of 8-12%, and the MES buffer has a pH of 5.8-6.0 and a concentration of 1 mol / L. The activating agent is selected from 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide or N-hydroxysuccinimide.

10. A method for preparing the low-density anti-settling thermally conductive potting compound according to any one of claims 1 to 9, characterized in that, Includes the following steps: S1. Vinyl silicone oil, silica powder, modified hollow glass microspheres, nano-calcium carbonate and platinum catalyst are mixed in a planetary mixer under normal pressure, and then mixed under vacuum conditions to obtain component A. S2. Vinyl silicone oil, end-chain hydrogen-containing silicone oil, side-chain hydrogen-containing silicone oil, silicon micro powder, modified hollow glass microspheres, nano-calcium carbonate and ethynylcyclohexanol are mixed in a planetary mixer under normal pressure, and then mixed under vacuum conditions to obtain component B. S3. Mix components A and B according to the mass ratio to obtain the thermally conductive potting compound.

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