Functional silicone oil for heat-conducting silicone grease as well as preparation method and application of functional silicone oil

Abstract

The invention discloses functional silicone oil for heat-conducting silicone grease, which is prepared from the following raw materials in parts by weight: 50 to 70 parts of modified polysiloxane, 10 to 20 parts of long-chain alkyl silicone oil, 5 to 10 parts of aluminum oxide sol, 5 to 10 parts of magnesium oxide sol and 2 to 5 parts of cyano-terminated silicone oil. By optimizing the ratio of the raw materials, the silicone oil is endowed with high thermal stability and good thermal conductivity by utilizing the unique molecular structure of the modified polysiloxane, the affinity of the long-chain alkyl silicone oil and the cyano-terminated silicone oil with the branching factor 0.2 with filler is improved, and the aluminum oxide sol and the magnesium oxide sol improve the heat conduction core index; the cyano-terminated silicone oil with the branching factor of 0.2 improves cohesive force, so that when the prepared functional silicone oil is used for heat-conducting silicone grease, the thermal resistance between an electronic element and a radiator can be remarkably reduced, and long-time stable operation of electronic equipment is guaranteed.

Description

Technical Field

[0001] The present invention relates to the field of new materials, and in particular to functional silicone oil for thermal conductive silicone grease, and a preparation method and application thereof. Background Art

[0002] With the rapid development of electronic technology, the power of electronic equipment continues to increase, and the problem of heat dissipation has become increasingly prominent. Thermal grease, as an important thermal conductive filling material, is widely used between heat-generating components such as CPUs and GPUs and radiators to reduce contact thermal resistance and improve heat dissipation efficiency. Traditional thermal greases are gradually unable to meet the needs of high-performance electronic equipment in terms of thermal conductivity and stability, and the performance of silicone oil, as a key basic component, is crucial. Existing ordinary silicone oils often have problems such as low thermal conductivity, insufficient thermal stability, and poor compatibility with thermal conductive fillers, which limits the comprehensive performance of thermal greases and makes them unable to adapt to complex and changing use environments. Therefore, the development of functional silicone oils for thermal greases with excellent performance is an urgent problem to be solved. Summary of the invention

[0003] Purpose of the invention: In order to solve the problems of poor thermal conductivity, poor stability and poor compatibility with fillers in existing thermal conductive silicone grease, the present invention provides a functional silicone oil for thermal conductive silicone grease and its preparation method and application.

[0004] In order to solve the above technical problems, the present invention discloses a functional silicone oil for thermal conductive silicone grease, which comprises the following raw materials in parts by weight:

[0005] 50-70 parts of modified polysiloxane, 10-20 parts of long-chain alkyl silicone oil, 5-10 parts of alumina sol, 5-10 parts of magnesium oxide sol, 2-5 parts of cyano-terminated silicone oil, wherein the modified polysiloxane is introduced with nitrogen-containing groups and boron-containing groups.

[0006] Wherein, the modified polysiloxane is prepared by the following method:

[0007] Preprocessing:

[0008] Put the silicone oil with dynamic viscosity of 70-75 cst in a dry three-necked flask, add anhydrous toluene as an organic solvent, add anhydrous toluene in a mass ratio of silicone oil to organic solvent of 1:3-5, stir and heat to 100°C under nitrogen atmosphere, keep for 1-2 hours, then cool to 70-80°C for standby use;

[0009] 2) Introducing nitrogen-containing group reaction:

[0010] Slowly add aminopropyltriethoxysilane in an amount of 25-40% of the mass of the silicone oil to the pretreated silicone oil solution, and add dibutyltin dilaurate in an amount of 0.5-0.8% of the total mass of the reactants. Continue stirring the reaction under nitrogen protection, maintain the reaction temperature at 100-120°C, and set the reaction time to 10-12 hours;

[0011] 3) Introducing boron-containing group reaction:

[0012] After the nitrogen-containing group introduction reaction is completed, the reaction system is cooled to 70-80°C, and triethyl borate is slowly added dropwise in an amount of 12-15% of the mass of the silicone oil. After the addition is completed, the reaction is continued by stirring, the temperature is maintained at 100°C, and the reaction time is 8-10 hours;

[0013] 4) Post-processing:

[0014] After the reaction is completed, the reaction system is naturally cooled to room temperature, and then the organic solvent and unreacted small molecules are removed by reduced pressure distillation to obtain a silicone oil product containing boron and nitrogen atoms, namely, modified polysiloxane.

[0015] The modified polysiloxane molecular chain introduces boron and nitrogen heterocyclic groups, which can effectively improve the thermal stability and thermal conductivity of silicone oil. The long-chain structure of long-chain alkyl silicone oil helps to improve the wettability of silicone oil and thermal conductive filler and enhance the dispersion uniformity of the system.

[0016] The alumina sol has a particle size of 10 to 50 nanometers and a mass fraction of alumina of 30 to 50 wt%.

[0017] The sol particle size of the magnesium oxide sol is 10 to 50 nanometers, and the mass fraction of magnesium oxide is 10 to 30 wt%.

[0018] The sol solvent of the aluminum oxide sol or magnesium oxide sol is a methyl-terminated polysiloxane with a dynamic viscosity of 75 to 100 cst. Both are used to further improve thermal conductivity and thermal stability.

[0019] Preferably, the branching factor of the cyano-terminated silicone oil is 0.2 to 0.4. The cyano-terminated silicone oil is used to form hydrogen bonding to optimize the overall heat resistance and further improve the wettability of the silicone oil with the thermal conductive filler.

[0020] The present application further provides a method for preparing the above-mentioned functional silicone oil for thermal grease, comprising the following steps:

[0021] (1) adding a formulated amount of modified polysiloxane and long-chain alkyl silicone oil into a reaction kettle, mixing and stirring, and cooling to room temperature to obtain a first mixed solution;

[0022] (2) slowly adding alumina sol to the first mixed solution obtained in step (1) while stirring, heating to 120-150° C. after the addition is complete, and continuing stirring for 1-2 hours to ensure that the alumina sol is fully integrated into the silicone oil system, and cooling to room temperature to obtain a second mixed solution;

[0023] (3) stirring the second mixed solution obtained in step (2) in an ice water bath, slowly adding 50-60% of the required amount of cyano-terminated silicone oil dropwise for 30-40 minutes, and continuing stirring for 1-2 hours to obtain a third mixed solution;

[0024] (4) maintaining an ice-water bath and stirring, slowly dropwise adding the magnesium oxide sol to the third mixed solution obtained in step (3), stirring while dropping, raising the temperature to 100-120° C. after the dropwise addition is completed, continuing stirring for 2-4 hours to ensure that the aluminum oxide sol is fully integrated into the silicone oil system, and cooling to room temperature to obtain a fourth mixed solution;

[0025] (5) Add the remaining cyano-terminated silicone oil to the fourth mixed solution obtained in step (4), react at 100-130° C. for 30-45 minutes, and after the reaction is completed, cool to room temperature to obtain functional silicone oil for thermal grease.

[0026] Preferably, in step (1), the modified polysiloxane and long-chain alkyl silicone oil are added into a reaction kettle, stirred and mixed at 80-100° C. for 30-60 minutes, the rotation speed is controlled at 500-800 rpm, and cooled to room temperature to obtain a first mixed solution.

[0027] In step (2), the stirring speed is controlled at 800-1000 rpm, and the dropping time is 20-30 minutes.

[0028] In step (3), the stirring speed is controlled at 800-1000 rpm, the dropping time is 30-40 minutes, and the stirring is continued for 1-2 hours to obtain a third mixed solution.

[0029] In step (4), the stirring speed is controlled at 800-1000 rpm, and the dropping time is 20-30 minutes.

[0030] The present invention further proposes the application of the functional silicone oil in the preparation of thermal conductive silicone grease.

[0031] The present invention optimizes the ratio of various raw materials and utilizes the unique molecular structure of modified polysiloxane to give silicone oil high thermal stability and good thermal conductivity, long-chain alkyl silicone oil and cyano-terminated silicone oil with a branching factor of 0.2 improve affinity with fillers, aluminum oxide sol and magnesium oxide sol improve the core index of thermal conductivity, and cyano-terminated silicone oil with a branching factor of 0.2 improves cohesion, so that the prepared functional silicone oil can significantly reduce the thermal resistance between electronic components and radiators when used in thermal conductive silicone grease, thereby ensuring long-term stable operation of electronic equipment.

[0032] Beneficial effects: Compared with the prior art, this application has the following advantages:

[0033] (1) The functional silicone oil of the present invention has a higher thermal conductivity, which can be increased by 200%-300% compared with traditional silicone oil, which is conducive to breaking through the thermal conductivity bottleneck of silicone oil, achieving efficient heat transfer, and improving the heat dissipation efficiency of electronic equipment;

[0034] (2) Excellent thermal stability. In the wide temperature range of -40℃ to 200℃, the performance of silicone oil is stable and will not decompose or flow, ensuring the reliable operation of electronic equipment in different environments;

[0035] (3) It has good compatibility with commonly used thermal conductive fillers such as alumina and boron nitride. During the preparation of thermal conductive silicone grease, the filler is evenly dispersed to avoid agglomeration, making the overall performance of the thermal conductive silicone grease stable and durable. DETAILED DESCRIPTION

[0036] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0037] In the following examples, the modified polysiloxane was prepared by the following steps:

[0038] 1) Preprocessing:

[0039] Silicone oil with a dynamic viscosity of 75 cst was placed in a dry three-necked flask, anhydrous toluene was added as an organic solvent, and anhydrous toluene was added in a ratio of 1:5 of silicone oil to organic solvent by mass, and the mixture was stirred and heated to 100°C under a nitrogen atmosphere, maintained for 1 hour, and then cooled to 80°C for standby use;

[0040] 2) Introducing nitrogen-containing group reaction:

[0041] Slowly add aminopropyltriethoxysilane dropwise in an amount of 30% of the mass of the silicone oil, and add it to the pretreated silicone oil solution. At the same time, add dibutyltin dilaurate in an amount of 0.7% of the total mass of the reactants. Continue stirring the reaction under nitrogen protection. The reaction temperature is maintained at 120° C. and the reaction time is set to 12 hours.

[0042] 3) Introducing boron-containing group reaction:

[0043] After the nitrogen-containing group introduction reaction is completed, the reaction system is cooled to 80°C, and triethyl borate is slowly added dropwise in an amount of 15% of the mass of the silicone oil. After the addition is completed, the reaction is continued by stirring, the temperature is maintained at 100°C, and the reaction time is 8 hours;

[0044] 4) Post-processing:

[0045] After the reaction is completed, the reaction system is naturally cooled to room temperature, and then the organic solvent and unreacted small molecules are removed by reduced pressure distillation to obtain a silicone oil product containing boron and nitrogen atoms, which is a modified polysiloxane.

[0046] In the following embodiments, the long-chain alkyl silicone oil used is a dodecyl-modified silicone oil with a dynamic viscosity of 500 cst, which is purchased from the market. The alumina sol is purchased from Hangzhou Jikang New Materials Co., Ltd., with a sol particle size of 10 to 30 nanometers, and the sol solvent is a methyl-terminated polysiloxane with a dynamic viscosity of 75 cst, and the mass fraction of alumina is 30 to 40 wt%. The sol particle size is customized according to requirements; the magnesium oxide sol is purchased from Hangzhou Jiuli Biomaterial Co., Ltd., with a sol particle size of 10 to 30 nanometers, and the sol solvent is a methyl-terminated polysiloxane with a dynamic viscosity of 75 cst, and the mass fraction of magnesium oxide is 10 to 20 wt%. The sol particle size is customized according to requirements; the cyano-terminated silicone oil is purchased from Shenzhen Jipeng Silicon Fluoride Materials Co., Ltd., and the branching factor is customized according to requirements.

[0047] Example 1

[0048] A functional silicone oil for thermal conductive silicone grease, comprising the following raw materials in parts by weight:

[0049] 50 parts of modified polysiloxane, 20 parts of long-chain alkyl silicone oil, 10 parts of alumina sol, 10 parts of magnesium oxide sol; 5 parts of cyano-terminated silicone oil with a branching factor of 0.2.

[0050] Prepared by the following steps:

[0051] (1) adding modified polysiloxane and long-chain alkyl silicone oil into a reaction kettle, stirring and mixing at 80° C. for 30 minutes, controlling the rotation speed at 500 rpm, and cooling to room temperature to obtain a first mixed solution;

[0052] (2) slowly adding alumina sol to the first mixed solution obtained in step (1) while stirring, the speed is controlled at 800 rpm, the dropping time is 20 minutes, the temperature is raised to 120° C. after the dropping is completed, and stirring is continued for 1 hour to ensure that the alumina sol is fully integrated into the silicone oil system, and the second mixed solution is obtained after cooling to room temperature;

[0053] (3) stirring the second mixed solution obtained in step (2) in an ice water bath at a speed of 800 rpm, slowly adding dropwise 50% of the required amount of cyano-terminated silicone oil with a branching factor of 0.2 for 30 minutes, and continuing stirring for 1 hour to obtain a third mixed solution;

[0054] (4) maintaining an ice-water bath and stirring, slowly dropwise adding the magnesium oxide sol to the third mixed solution obtained in step (3), stirring while dropping, controlling the rotation speed at 800 rpm, and the dropping time for 20 minutes. After the dropwise addition is completed, the temperature is raised to 100° C. and stirring is continued for 2 hours to ensure that the aluminum oxide sol is fully integrated into the silicone oil system. After cooling to room temperature, a fourth mixed solution is obtained;

[0055] (5) Add the remaining 50% of cyano-terminated silicone oil with a branching factor of 0.2 to the fourth mixed solution obtained in step (4), react at 100° C. for 30 minutes, and after the reaction is completed, cool to room temperature to obtain functional silicone oil for thermal grease.

[0056] After testing, the thermal conductivity of the silicone oil obtained (thermal conductivity: test standard ASTM D5470) is 0.51W / (m·K);

[0057] The spherical AlN powder with a particle size distribution of 5 to 15 microns was mixed at a mass ratio of 10:90. The mixing process was as follows: the two were mixed and stirred at a speed of 1500 rpm for 15 minutes using a planetary mixer, and then vacuumed to 2kPa, and degassed at a speed of 1000 rpm for 10 minutes to obtain the thermal grease for testing. The thermal conductivity was 6.1W / (m·K). After aging at 200℃ for 10,000 hours, the thermal conductivity change rate of the thermal grease was 3.1%.

[0058] Example 2

[0059] A functional silicone oil for thermal conductive silicone grease, comprising the following raw materials in parts by weight:

[0060] 70 parts of modified polysiloxane, 10 parts of long-chain alkyl silicone oil, 5 parts of alumina sol, 5 parts of magnesium oxide sol, and 2 parts of cyano-terminated silicone oil with a branching factor of 0.2.

[0061] Prepared by the following steps:

[0062] (1) adding modified polysiloxane and long-chain alkyl silicone oil into a reaction kettle, stirring and mixing at 100° C. for 60 minutes, controlling the rotation speed at 800 rpm, and cooling to room temperature to obtain a first mixed solution;

[0063] (2) slowly adding alumina sol to the first mixed solution obtained in step (1) while stirring, the speed is controlled at 1000 rpm, the dropping time is 30 minutes, and after the dropping is completed, the temperature is raised to 150° C. and stirring is continued for 2 hours to ensure that the alumina sol is fully integrated into the silicone oil system, and the second mixed solution is obtained after cooling to room temperature;

[0064] (3) stirring the second mixed solution obtained in step (2) in an ice water bath at a speed of 1000 rpm, slowly adding dropwise 50% of the required amount of cyano-terminated silicone oil with a branching factor of 0.2 for 40 minutes, and continuing stirring for 2 hours to obtain a third mixed solution;

[0065] (4) maintaining an ice-water bath and stirring, slowly dropwise adding the magnesium oxide sol to the third mixed solution obtained in step (3), stirring while dropping, controlling the rotation speed at 1000 rpm, and the dropping time for 30 minutes. After the dropwise addition is completed, the temperature is raised to 120° C. and stirring is continued for 4 hours to ensure that the aluminum oxide sol is fully integrated into the silicone oil system. After cooling to room temperature, a fourth mixed solution is obtained;

[0066] (5) Add the remaining 50% of cyano-terminated silicone oil with a branching factor of 0.2 to the fourth mixed solution obtained in step (4), react at 130° C. for 45 minutes, and after the reaction is completed, cool to room temperature to obtain functional silicone oil for thermal grease.

[0067] After testing, the thermal conductivity of the silicone oil was 0.68W / (m·K);

[0068] The spherical AlN powder with a particle size distribution of 5 to 15 microns was mixed at a mass ratio of 10:90. The mixing process was as follows: the two were mixed and stirred at a speed of 1500 rpm for 15 minutes using a planetary mixer, and then vacuumed to 2kPa, and degassed at a speed of 1000 rpm for 10 minutes to obtain the thermal grease for testing. The thermal conductivity was 6.9W / (m·K). After aging at 200℃ for 10,000 hours, the thermal conductivity change rate of the thermal grease was 1.8%.

[0069] Example 3

[0070] A functional silicone oil for thermal conductive silicone grease, comprising the following raw materials in parts by weight:

[0071] 60 parts of modified polysiloxane, 15 parts of long-chain alkyl silicone oil, 7.5 parts of alumina sol, 7.5 parts of magnesium oxide sol, and 3.5 parts of cyano-terminated silicone oil with a branching factor of 0.2. Prepared by the following steps:

[0072] (1) adding modified polysiloxane and long-chain alkyl silicone oil into a reaction kettle, stirring and mixing at 90° C. for 45 minutes, controlling the rotation speed at 650 rpm, and cooling to room temperature to obtain a first mixed solution;

[0073] (2) slowly adding alumina sol to the first mixed solution obtained in step (1) while stirring, the speed is controlled at 900 rpm, the dropping time is 25 minutes, and after the dropping is completed, the temperature is raised to 135° C. and stirring is continued for 1.5 hours to ensure that the alumina sol is fully integrated into the silicone oil system. After cooling to room temperature, a second mixed solution is obtained;

[0074] (3) stirring the second mixed solution obtained in step (2) in an ice water bath at a speed of 900 rpm, slowly adding dropwise 50% of the required amount of cyano-terminated silicone oil with a branching factor of 0.2 for 35 minutes, and continuing stirring for 1.5 hours to obtain a third mixed solution;

[0075] (4) maintaining an ice-water bath and stirring, slowly dropwise adding the magnesium oxide sol to the third mixed solution obtained in step (3), stirring while dropping, controlling the rotation speed at 900 rpm, and the dropping time for 25 minutes. After the dropwise addition is completed, the temperature is raised to 110° C. and stirring is continued for 3 hours to ensure that the aluminum oxide sol is fully integrated into the silicone oil system. After cooling to room temperature, a fourth mixed solution is obtained;

[0076] (5) Add the remaining 50% of cyano-terminated silicone oil with a branching factor of 0.2 to the fourth mixed solution obtained in step (4), react at 115° C. for 40 minutes, and after the reaction is completed, cool to room temperature to obtain functional silicone oil for thermal grease.

[0077] After testing, the thermal conductivity of the silicone oil was 0.59W / (m·K);

[0078] The spherical AlN powder with a particle size distribution of 5 to 15 microns was mixed at a mass ratio of 10:90. The mixing process was as follows: After the two were mixed, they were stirred at a speed of 1500 rpm for 15 minutes using a planetary mixer, and then vacuumed to 2kPa, and degassed at a speed of 1000 rpm for 10 minutes to obtain the thermal grease for testing. The thermal conductivity was 6.5W / (m·K). After aging at 200℃ for 10,000 hours, the thermal conductivity change rate of the thermal grease was 2.3%.

[0079] Comparative Example 1

[0080] Commercially available silicone oil (Dow XIAMETER TM PMX-200Silicone Fluid 350 cSt);

[0081] After testing, the thermal conductivity of the silicone oil is 0.16W / (m·K);

[0082] The spherical AlN powder with a particle size distribution of 5 to 15 microns was mixed at a mass ratio of 10:90. The mixing process was as follows: the two were mixed and stirred at a speed of 1500 rpm for 15 minutes using a planetary mixer, and then vacuumed to 2kPa and degassed at a speed of 1000 rpm for 10 minutes. No thermal grease for testing could be obtained. The obtained product was in the form of a hard block, indicating that the wettability of this silicone oil and AlN powder was poor and it could not be made into a paste at this filling rate.

[0083] Comparative Example 2

[0084] Use commercially available long-chain alkyl silicone oil (500cst)

[0085] After testing, the thermal conductivity of the silicone oil is 0.13W / (m·K);

[0086] The spherical AlN powder with a particle size distribution of 5 to 15 microns was mixed at a mass ratio of 10:90. The mixing process was as follows: the two were mixed and stirred at a speed of 1500 rpm for 15 minutes using a planetary mixer, and then vacuumed to 2kPa, and degassed at a speed of 1000 rpm for 10 minutes to obtain the thermal grease for testing. The thermal conductivity was 5.8W / (m·K). After aging at 200℃ for 10,000 hours, the thermal conductivity change rate of the thermal grease was 12.3%.

[0087] Comparative Example 3

[0088] Only the modified polysiloxanes described in the present invention are used.

[0089] After testing, the thermal conductivity of the silicone oil is 0.38W / (m·K)

[0090] The spherical AlN powder with a particle size distribution of 5 to 15 microns was mixed at a mass ratio of 10:90. The mixing process was as follows: After the two were mixed, they were stirred at a speed of 1500 rpm for 15 minutes using a planetary mixer, and then vacuumed to 2kPa, and degassed at a speed of 1000 rpm for 10 minutes to obtain the thermal grease for testing. The thermal conductivity was 5.1W / (m·K). After aging at 200℃ for 10,000 hours, the thermal conductivity change rate of the thermal grease was 7.3%.

[0091] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A functional silicone oil for thermal grease, characterized in that: According to weight parts, it includes the following raw materials: 50-70 parts of modified polysiloxane, 10-20 parts of long-chain alkyl silicone oil, 5-10 parts of alumina sol, 5-10 parts of magnesium oxide sol, and 2-5 parts of cyano-terminated silicone oil, wherein the modified polysiloxane is introduced with nitrogen-containing groups and boron-containing groups.

2. The functional silicone oil for thermal grease according to claim 1, characterized in that: The modified polysiloxane is prepared by the following method: 1) Preprocessing: Place silicone oil with a dynamic viscosity of 70-75 cst in a dry three-necked flask, add anhydrous toluene as an organic solvent, add anhydrous toluene in a mass ratio of 1:3-5 between silicone oil and organic solvent, stir and heat to 100°C under a nitrogen atmosphere, maintain for 1-2 hours, then cool to 70-80°C for standby use; 2) Introducing nitrogen-containing group reaction: Slowly add aminopropyltriethoxysilane in an amount of 25-40% of the mass of the silicone oil to the pretreated silicone oil solution, and add dibutyltin dilaurate in an amount of 0.5-0.8% of the total mass of the reactants. Continue stirring the reaction under nitrogen protection, keep the reaction temperature at 100-120°C, and set the reaction time to 10-12 hours; 3) Introduction of boron-containing group reaction: After the nitrogen-containing group introduction reaction is completed, the reaction system is cooled to 70-80°C, and triethyl borate is slowly added dropwise in an amount of 12-15% of the mass of the silicone oil. After the addition is completed, the reaction is continued by stirring, the temperature is maintained at 100°C, and the reaction time is 8-10 hours; 4) Post-processing: After the reaction is completed, the reaction system is naturally cooled to room temperature, and then the organic solvent and unreacted small molecules are removed by reduced pressure distillation to obtain a silicone oil product containing boron and nitrogen atoms, namely, modified polysiloxane.

3. The functional silicone oil for thermal grease according to claim 1, characterized in that: The long-chain alkyl silicone oil is dodecyl-modified silicone oil with a dynamic viscosity of 500 cst.

4. The functional silicone oil for thermal grease according to claim 1, characterized in that: The sol particle size of the alumina sol is 10-50 nanometers, and the mass fraction of alumina is 30-50wt%; the sol particle size of the magnesia sol is 10-50 nanometers, and the mass fraction of magnesia is 10-30wt%; the sol solvent of the alumina sol or magnesia sol is methyl-terminated polysiloxane with a dynamic viscosity of 75-100 cst.

5. The functional silicone oil for thermal grease according to claim 1, characterized in that: The branching factor of the cyano-terminated silicone oil is 0.2-0.

4.

6. The method for preparing the functional silicone oil for thermal grease according to any one of claims 1 to 5, characterized in that: The steps include: (1) adding a prescribed amount of modified polysiloxane and long-chain alkyl silicone oil into a reaction kettle, mixing and stirring, and cooling to room temperature to obtain a first mixed solution; (2) slowly adding alumina sol to the first mixed solution obtained in step (1) while stirring; after the addition is complete, heating to 120-150° C. and continuing stirring for 1-2 hours to ensure that the alumina sol is fully integrated into the silicone oil system; and cooling to room temperature to obtain a second mixed solution; (3) stirring the second mixed solution obtained in step (2) in an ice water bath, slowly adding dropwise 50-60% of the required amount of cyano-terminated silicone oil for 30-40 minutes, and continuing stirring for 1-2 hours to obtain a third mixed solution; (4) maintaining an ice-water bath and stirring, slowly dropwise adding the magnesium oxide sol to the third mixed solution obtained in step (3), stirring while dropping, raising the temperature to 100-120° C. after the dropwise addition is complete, and continuing to stir for 2-4 hours to ensure that the aluminum oxide sol is fully integrated into the silicone oil system, and cooling to room temperature to obtain a fourth mixed solution; (5) Add the remaining cyano-terminated silicone oil to the fourth mixed solution obtained in step (4), react at 100-130° C. for 30-45 minutes, and cool to room temperature after the reaction to obtain functional silicone oil for thermal grease.

7. The preparation method according to claim 6, characterized in that: In step (1), the modified polysiloxane and long-chain alkyl silicone oil are added into a reaction kettle, stirred and mixed at 80-100° C. for 30-60 minutes, the rotation speed is controlled at 500-800 rpm, and cooled to room temperature to obtain a first mixed solution.

8. The preparation method according to claim 6, characterized in that: In step (2), the stirring speed is controlled at 800-1000 rpm, and the dropping time is 20-30 minutes; in step (3), the stirring speed is controlled at 800-1000 rpm, and the dropping time is 30-40 minutes. Stirring is continued for 1-2 hours to obtain a third mixed solution.

9. The preparation method according to claim 6, characterized in that: In step (4), the stirring speed is controlled at 800-1000 rpm, and the dropping time is 20-30 minutes.

10. Use of the functional silicone oil according to any one of claims 1 to 5 in the preparation of thermal conductive silicone grease.