Heat-conducting silicon paste treated by propyltrimethoxysilane oligomer and preparation method of heat-conducting silicon paste

Abstract

The invention relates to the technical field of heat-conducting interface materials, and discloses a high-heat-conducting silicon paste subjected to surface treatment of a propyl trimethoxy silane oligomer and a preparation method, and the method comprises the following steps: firstly preparing the propyl trimethoxy silane oligomer, then mixing the propyl trimethoxy silane oligomer with vinyl silicone oil, and finally uniformly mixing the mixture with an aluminum oxide filler under a vacuum condition to prepare the silicon paste. The propyl trimethoxy silane oligomer is used for carrying out surface treatment on the aluminum oxide filler, so that the comprehensive performance of the silicon paste is remarkably improved. Compared with a sample without addition treatment, when the propyltrimethoxysilane oligomer is used, the thermal conductivity coefficient of the silicon paste filled with 70vol% of aluminum oxide is increased by more than 70%, the thermal resistance is reduced by about 50%, the penetration is remarkably increased, and the thermal interface material with low cost, high thermal conductivity coefficient and low thermal resistance is obtained. The preparation method is simple in process and easy for industrial production.

Description

Technical Field

[0001] This invention relates to the field of thermal interface materials technology, specifically to a thermally conductive silicone grease with propyltrimethoxysilane oligomer as a surface treatment agent and vinyl silicone oil as a matrix, and its preparation method. Background Technology

[0002] With the continuous increase in power density of electronic devices, heat dissipation has become a key factor restricting their performance and reliability. Thermal grease, as a thermal interface material filling the space between the heat source and the heat sink, plays a crucial role in eliminating interfacial air and constructing efficient heat conduction channels. The performance of thermal grease is mainly determined by the polymer matrix and the thermally conductive filler. Currently, most commercial thermal greases use dimethyl silicone oil as the matrix material, but its poor interfacial compatibility with the filler limits the increase in filler content and leads to problems such as silicone oil precipitation and increased thermal resistance during long-term use.

[0003] To improve the interfacial compatibility between the filler and the matrix, silane coupling agents are typically used to treat the filler surface. However, traditional small-molecule silane coupling agents (such as KH-550 and KH-560) are prone to volatilization and migration at high temperatures, leading to decreased interfacial stability and affecting the durability of thermal conductivity.

[0004] Silane oligomers are considered a new generation of highly efficient surface treatment agents due to their high boiling point, low volatility, and high functional group density. Chinese patent application CN111763321A discloses a method for preparing propylsilane oligomers. This oligomer is intended for use in building waterproofing materials, but it does not address thermally conductive interface materials, and in particular, it does not consider the dispersion of the treated thermally conductive filler in a specific matrix silicone oil and its impact on the thermal conductivity of the interface material.

[0005] In existing technologies, thermally conductive silicone pastes prepared using dimethyl silicone oil as a matrix and filled with thermally conductive fillers treated with conventional silane coupling agents typically have low thermal conductivity, mostly below 2.0 W / (m·K). Furthermore, these pastes often exhibit low cone penetration, making it difficult to simultaneously achieve low thermal resistance and good workability. While alkoxy-terminated polysiloxanes can produce thermal interface materials with high thermal conductivity, their high cost hinders market competitiveness. Therefore, developing a novel, low-cost thermally conductive silicone paste that simultaneously achieves high thermal conductivity, low thermal resistance, and excellent workability holds significant market potential. Summary of the Invention

[0006] The purpose of this invention is to provide a thermally conductive silicone grease treated with propyltrimethoxysilane oligomers and its preparation method. This invention aims to overcome the safety and technical shortcomings of existing methods that directly use small-molecule silane coupling agents or crosslinking agents as thermally conductive filler treatment agents, and to provide a low-cost, high-performance thermally conductive silicone grease and its preparation method. This thermally conductive silicone grease uses a specific propyltrimethoxysilane oligomer to treat the surface of the thermally conductive filler, and selects vinyl silicone oil as the matrix and alumina as the filler, achieving synergistic optimization of thermal conductivity, thermal resistance, and cone penetration.

[0007] The present invention adopts the following technical solution: A thermally conductive silicone grease treated with propyltrimethoxysilane oligomers, said thermally conductive silicone grease being made from the following components in parts by weight: (1) Vinyl silicone oil: 100 parts by weight; (2) Alumina filler: 880-1020 parts by weight; (3) Propyltrimethoxysilane oligomer, the amount of which is 1.5-2.5% of the total weight of alumina filler.

[0008] The thermally conductive silicone grease is prepared using the following method: (1) Using vinyl silicone oil with a dynamic viscosity of 100 mPa·s at 25 ℃ as the base, put it into a container with propyltrimethoxysilane oligomer, place the container in a non-invasive homogenizer, and mix for 1 min at a speed of 1800 rpm and a relative vacuum of -99.5 kPa to make the vinyl silicone oil and oligomer evenly mixed. (2) The alumina filler is loaded into a container, and the container is placed in a homogenizer again. The mixture is mixed for 3 min at 1800 rpm and a relative vacuum of -99.5 kPa to obtain thermally conductive silicone paste. The density of vinyl silicone oil and propyltrimethoxysilane oligomers is 0.96 g / cm³. 3 Calculations show that the density of the alumina filler is 4.0 g / cm³. 3 Calculations show that the volume fraction of alumina filler in thermal conductive silicone grease is 65%~75%.

[0009] Preferably, the amount of propyltrimethoxysilane oligomer is 2.0% of the mass of alumina filler, and the volume fraction of alumina filler in the thermally conductive silicone paste is 70%.

[0010] The propyltrimethoxysilane oligomer is prepared by the following steps: (1) Add propyltrimethoxysilane and methanol solvent to a three-necked flask equipped with a reflux condenser, thermometer and stirring device; (2) Heat the mixture to 35-50 °C with stirring, and then add the pre-prepared mixed solution of methanol, hydrochloric acid and water dropwise into the flask; after the mixed solution is added, raise the temperature and carry out the aging reaction for a period of time. (3) After the aging reaction is complete, and the temperature of the mixture drops to room temperature, adjust the pH of the mixture to 7-8 with sodium bicarbonate; then filter and collect the filtrate. (4) Under normal pressure, the filtrate after filtration is heated at a rate of 5~10 °C / min until all the solvent is evaporated; after the mixture is cooled to room temperature, the propyltrimethoxysilane oligomer is obtained.

[0011] In step (1), the mass ratio of methanol to propyltrimethoxysilane is (1 / 3~1):1; in step (2), the mass ratio of methanol to water in the mixed solution composed of methanol, hydrochloric acid and water is (1~3):1, the mass of hydrochloric acid is 1%~8% of the mass of propyltrimethoxysilane, the molar ratio of water to propyltrimethoxysilane is (0.3~2.1):1, and the time for adding the mixed solution is 10~60 min; in step (3), the aging reaction temperature is 60~90 ℃, and the aging reaction time is 2~10 hours.

[0012] Compared with the prior art, the present invention has the following beneficial effects: (1) When a specific structure of propyltrimethoxysilane oligomer (added at 1.5-2.5 wt% of filler) is combined with a vinyl silicone oil matrix, the thermal conductivity of the silicone paste can be effectively improved and the interfacial thermal resistance can be reduced with a 70 vol% alumina filler content, while the cone penetration of the silicone paste can be significantly improved.

[0013] (2) Propyltrimethoxysilane oligomers form a strong interfacial chemical anchor with the filler surface through multiple hydroxyl groups, forming Al-O-Si bonds, which promotes the chemical bonding between the surface treatment agent and the thermally conductive filler. This stable interfacial layer can not only effectively reduce the interfacial thermal resistance, but more importantly, it fundamentally inhibits the migration and precipitation tendency of silicone oil under long-term use or high temperature.

[0014] (3) At a high filling volume of 70 vol%, the prepared thermally conductive silicone paste can still maintain a high cone penetration. The paste has good softness and spreadability, which is convenient for application and coating in practical applications. It can effectively fill the micro-defects at the interface and obtain a lower and more stable contact thermal resistance. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 The product of Embodiment 1 of the present invention 1 H NMR spectrum.

[0017] Figure 2 The product of Embodiment 2 of the present invention 1 H NMR spectrum.

[0018] Figure 3 The product of Embodiment 3 of the present invention 1 H NMR spectrum.

[0019] Figure 4 The product of Example 4 of the present invention 1 H NMR spectrum. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1 Preparation of propyltrimethoxysilane oligomers (molar ratio of propyltrimethoxysilane to water is 1:0.3) S1. Add 30 g (0.183 mol) of propyltrimethoxysilane and 10 g of methanol solvent to a three-necked flask equipped with a reflux condenser, thermometer and stirring device; S2. Under stirring, the temperature of the mixture was raised to 45 °C, and a mixed solution consisting of 0.99 g methanol, 0.9 g hydrochloric acid (12 mol / L) and 0.99 g water (0.055 mol) was added dropwise to the reactor over 20 min; after the addition of the mixed solution was completed, the temperature of the mixture was controlled at 60 °C and the aging reaction was carried out for 2 h. S3. After cooling to room temperature, neutralize the product with sodium bicarbonate and adjust its pH to 7-8. Then filter and collect the filtrate. S4. Under normal pressure, the filtrate is gradually heated until the solvent in the flask is evaporated. After cooling to room temperature, propyltrimethoxysilane oligomer is obtained.

[0022] Tests: GPC analysis of the product revealed that the number-average molecular weight of the propyltrimethoxysilane oligomer was 511 g / mol and the polydispersity index (PDI) was 1.08.

[0023] Example 2 Preparation of propyltrimethoxysilane oligomers (propyltrimethoxysilane to water molar ratio of 1:0.7) S1. This step is the same as in Example 1; S2. The difference between this step and Example 1 is that the temperature of the mixture is raised to 35 °C, the mixed solution consists of 2.31 g (0.128 mol) water, 2.31 g methanol and 0.9 g hydrochloric acid with a concentration of 12 mol / L, the dropping time is 30 min, the aging reaction temperature is 70 °C, and the aging reaction time is 2 h; S3. This step is the same as in Example 1; S4. This step is the same as in Example 1.

[0024] Tests: GPC analysis of the product revealed that the number-average molecular weight of the propyltrimethoxysilane oligomer was 776 g / mol and the polydispersity index (PDI) was 1.06.

[0025] Example 3 Preparation of propyltrimethoxysilane oligomers (propyltrimethoxysilane to water molar ratio of 1:1.5) S1. This step is the same as in Example 1; S2. The difference between this step and Example 1 is that the temperature of the mixture is raised to 45 °C, and the mixed solution consists of 4.94 g (0.275 mol) water, 4.94 g methanol and 0.9 g hydrochloric acid with a concentration of 12 mol / L; the dropping time is 60 min, the aging reaction temperature is 80 °C, and the aging reaction time is 8 h. S3. This step is the same as in Example 1; S4. This step is the same as in Example 1.

[0026] Tests: GPC analysis of the product revealed that the number-average molecular weight of the propyltrimethoxysilane oligomer was 1084 g / mol and the polydispersity index (PDI) was 1.18.

[0027] Example 4 Preparation of propyltrimethoxysilane oligomers (molar ratio of propyltrimethoxysilane to water is 1:2.1) S1. This step is the same as in Example 1; S2. The difference between this step and Example 1 is that the temperature of the mixture is raised to 40 °C, and the mixed solution consists of 6.92 g (0.384 mol) of water, 6.92 g of methanol and 0.9 g of hydrochloric acid with a concentration of 12 mol / L; the dropping time is 50 min, the aging reaction temperature is 70 °C, and the aging reaction time is 5 h. S3. This step is the same as in Example 1; S4. This step is the same as in Example 1.

[0028] Tests: GPC analysis of the product revealed that the number-average molecular weight of the propyltrimethoxysilane oligomer was 923 g / mol and the polydispersity index (PDI) was 1.24.

[0029] Comparative Example 1 Preparation of propyltrimethoxysilane oligomers (molar ratio of propyltrimethoxysilane to water is 1:3) S1. This step is the same as in Example 1; S2. The difference between this step and Example 1 is that the mixed solution consists of 9.88 g (0.549 mol) of water, 9.88 g of methanol and 0.9 g of hydrochloric acid with a concentration of 12 mol / L; S3. This step is the same as in Example 1; S4. This step is the same as in Example 1, but the product gels during the process of heating and desolventizing.

[0030] Comparative Example 2 Preparation of propyltrimethoxysilane oligomers (molar ratio of propyltrimethoxysilane to water is 1:0.1) S1. This step is the same as in Example 1; S2. The difference between this step and Example 1 is that the temperature of the mixture is raised to 40 °C, and the mixed solution consists of 0.33 g (0.0183 mol) water, 0.33 g methanol and 0.9 g hydrochloric acid with a concentration of 12 mol / L; the dropping time is 60 min, the aging reaction temperature is 70 °C, and the aging reaction time is 2 h. S3. This step is the same as in Example 1; S4. This step is the same as in Example 1.

[0031] Tests: GPC analysis of the product revealed that the number-average molecular weight of the propyltrimethoxysilane oligomer was 466 g / mol and the polydispersity index (PDI) was 1.05.

[0032] Application Example 1 Using the propyltrimethoxysilane oligomer prepared in Example 1 as an alumina surface treatment agent, a thermally conductive silicone paste was prepared. S1. Place 3g of vinyl silicone oil with a dynamic viscosity of 100 mPa·s at 25 °C and 0.57g of propyltrimethoxysilane oligomer (product of Example 1) in a non-invasive homogenizer and mix for 1 min at 1800 rpm under reduced pressure to a relative vacuum of -99.5 kPa. S2. Add 28.56 g of alumina (particle size 70 µm) filler, place it in a homogenizer again, and mix for 3 min under the same conditions to obtain thermally conductive silicone paste.

[0033] Test: The thermal conductivity of this silicone paste was measured to be 1.973 W·m using a thermal conductivity meter. -1 ·k -1 Its thermal resistance is 32.31 K·cm. 2 / W, the 1 / 4 taper of this silicone paste is 44.9 (0.1 mm).

[0034] Application Example 2 Using the propyltrimethoxysilane oligomer prepared in Example 2 as an alumina surface treatment agent, a thermally conductive silicone paste was prepared. S1. Place 3 g of vinyl silicone oil with a dynamic viscosity of 100 mPa·s at 25 °C and 0.57 g of propyltrimethoxysilane oligomer (product of Example 2) in a non-invasive homogenizer and mix for 1 min at 1800 rpm under reduced pressure to a relative vacuum of -99.5 kPa. S2. This step is the same as in Example 1.

[0035] Test: The thermal conductivity of this silicone paste was measured to be 1.963 W·m using a thermal conductivity meter. -1 ·k -1 Its thermal resistance is 27.72 K·cm. 2 / W, the 1 / 4 taper of this silicone paste is 43.5 (0.1 mm).

[0036] Application Example 3 Using the propyltrimethoxysilane oligomer prepared in Example 3 as an alumina surface treatment agent, a thermally conductive silicone paste was prepared. S1. Place 3 g of vinyl silicone oil with a dynamic viscosity of 100 mPa·s at 25 °C and 0.57 g of propyltrimethoxysilane oligomer (product of Example 3) in a non-invasive homogenizer and mix for 1 min at a speed of 1800 rpm under reduced pressure to a relative vacuum of -99.5 kPa. S2. This step is the same as in Example 1.

[0037] Test: The thermal conductivity of this silicone paste was measured to be 1.927 W·m using a thermal conductivity meter. -1 ·k -1The thermal resistance is 27.97 K·cm. 2 / W. The 1 / 4 cone penetration of the silicone paste was measured to be 44.4 (0.1 mm).

[0038] Application Example 4 Using the propyltrimethoxysilane oligomer prepared in Example 4 as an alumina surface treatment agent, a thermally conductive silicone paste was prepared. S1. Place 3 g of vinyl silicone oil with a dynamic viscosity of 100 mPa·s at 25 °C and 0.57 g of propyltrimethoxysilane oligomer (product of Example 4) in a non-invasive homogenizer and mix for 1 min at 1800 rpm under reduced pressure to a relative vacuum of -99.5 kPa. S2. This step is the same as in Example 1.

[0039] Test: The thermal conductivity of this silicone paste was measured to be 1.869 W·m using a thermal conductivity meter. -1 ·k -1 Its thermal resistance is 28.75 K·cm. 2 / W, the 1 / 4 cone penetration of the silicone paste was measured to be 42.2 (0.1 mm).

[0040] Comparative Application Example 1 Preparation of thermally conductive silicone paste (without using propyltrimethoxysilane oligomer as a treatment agent) S1. Place 3 g of vinyl silicone oil with a dynamic viscosity of 100 mPa·s at 25 ℃ in a non-invasive homogenizer and mix for 1 min at a speed of 1800 rpm under reduced pressure to a relative vacuum of -99.5 kPa. S2. This step is the same as in Example 1.

[0041] Test: The thermal conductivity of this silicone paste was measured to be 1.119 W·m using a thermal conductivity meter. -1 ·k -1 Its thermal resistance is 55.95 K·cm. 2 / W, the 1 / 4 cone penetration of the silicone paste was measured to be 39.3 (0.1 mm).

[0042] Comparative Application Example 2 Thermally conductive silicone paste was prepared using propyltrimethoxysilane as a filler. S1. Place 3 g of vinyl silicone oil with a dynamic viscosity of 100 mPa·s at 25 ℃ and 0.57 g of propyltrimethoxysilane monomer in a non-invasive homogenizer and mix for 1 min at a speed of 1800 rpm under reduced pressure to a relative vacuum of -99.5 kPa. S2. This step is the same as in Example 1.

[0043] Test: The thermal conductivity of this silicone paste was measured to be 1.057 W·m using a thermal conductivity meter. -1 ·k -1 Its thermal resistance is 58.94 K·cm. 2 / W, the 1 / 4 cone penetration of the silicone paste was measured to be 48.83 (0.1 mm).

[0044] Comparative Application Example 3 The propyltrimethoxysilane oligomer obtained in Comparative Example 2 was used as the treatment agent. S1. Place 3 g of vinyl silicone oil with a dynamic viscosity of 100 mPa·s at 25 ℃ and 0.57 g of propyltrimethoxysilane oligomer prepared in Comparative Example 2 in a non-invasive homogenizer and mix for 1 min at a speed of 1800 rpm and a pressure reduced to a relative vacuum of -99.5 kPa. S2. This step is the same as in Example 1.

[0045] Test: The thermal conductivity of this silicone paste was measured to be 0.996 W·m using a thermal conductivity meter. -1 ·k -1 Its thermal resistance is 62.31 K·cm. 2 / W, the 1 / 4 cone penetration of the silicone paste was measured to be 47.25 (0.1 mm).

[0046] The testing standards and methods adopted in this invention are as follows: GPC test: A PL-GPC50 gel permeation chromatograph was used. Polydimethylsiloxane (Polymer Standards, Inc.) with a known molecular weight was used as the standard sample. Toluene was used as the mobile phase, the flow rate was 1.0 mL / min, and the column temperature was 35 ℃. The molecular weight was calculated by converting the time of sample elution in the column to the time of standard sample flow. Dynamic viscosity test: According to GB / T 2794-2022 standard, the dynamic viscosity was measured using a Brookfield DV2TRVTJ0 rotational viscometer at a constant temperature of 25±0.1 ℃ and a rotation speed of 200 rpm for 5 min. The uncertainty of dynamic viscosity was 1%. Thermal conductivity test of silicone paste: The hot and cold electrode temperatures of the thermal conductivity meter were set to 80 °C and 20 °C, respectively. The test mold was a circular tubular plastic tube with an inner diameter of 14 mm and an internal area of ​​approximately 615 mm². 2 The height is approximately 2-3 mm. Apply thermally conductive silicone paste to the circular tubular mold, set the pressure between the two electrodes to 30 N, and start the test when the thermal resistance fluctuation is less than 1%. Set the data acquisition time to 50 s, and refer to ASTM D5470 for the test standard.

[0047] 1 / 4 cone penetration tester: Take 10-15 g of silicone paste sample and place it in the test cup. Spread the sample until it is flush with the rim of the cup. Lock the cup in the center of the test platform. Adjust the position of the cone so that the cone tip just contacts the sample surface. Test the cone penetration value of the silicone paste at 25 ℃ after the cone has fallen for 5 seconds. The test standard refers to GB / T269 "Determination of cone penetration of greases and petroleum greases" and ISO 2137-2020 "Petroleum products and lubricants - Determination of cone penetration of greases and petroleum products".

[0048] X-ray photoelectron spectroscopy (XPS): Elemental analysis of the sample surface is performed by photoelectrons excited by low-power K-Alpha X-rays, with the binding energy of C1s of the CC bond at 284.80 eV as a reference.

[0049] X-ray photoelectron spectroscopy (XPS) was used to analyze the chemical state of the filler surface to verify the grafting of oligomers.

[0050] Table 1. Binding energy of Al 2p in various silicone pastes As shown in Table 1, after oligomer treatment (Application Example 2, Application Example 4), the binding energy of the Al 2p peak showed a clear positive shift compared to the untreated blank filler (74.33 eV). This shift in binding energy is a typical characteristic of the change in the chemical environment of Al atoms. The direct cause is the condensation of Al-OH on the filler surface with the silanol groups of the oligomer to form Al-O-Si covalent bonds. Since silicon atoms are more electronegative than aluminum atoms, the bonding electron cloud will be biased towards the silicon atom side, resulting in a decrease in the electron cloud density around the aluminum atom, thereby increasing the binding energy of its inner-shell electrons.

[0051] Therefore, this change in XPS data provides direct evidence that propyltrimethoxysilane oligomers are chemically bonded to the surface of Al2O3 filler, which provides a key basis for explaining why this system has excellent interfacial stability and long-term reliability.

[0052] Table 2. Effect of oligomers on the thermal conductivity of silicone paste

[0053] Notes: a. Monomer refers to propyltrimethoxysilane; b. In... 1 The propyltrimethoxysilane oligomer molecule structure shown in the H-NMR spectrum contains a methylene group (Si-CH2C) attached to the terminal methyl group. H The area integral value of the methoxy proton calculated when the integral area of ​​the 2CH3 proton is 2.

[0054] As can be seen from the test data in Table 2, the overall performance of the thermally conductive silicone grease prepared using the propyltrimethoxysilane oligomer disclosed in this application as a thermally conductive filler surface treatment agent is significantly improved. Compared with Application Example 1, which did not add any surface treatment agent, these silicone greases have the lowest thermal conductivity, the highest thermal resistance, and the smallest cone penetration.

[0055] The thermally conductive silicone grease prepared using the technical solution of this application shows a comprehensive improvement in thermal conductivity, thermal resistance, and cone penetration compared to Comparative Application Example 1. Compared to Comparative Application Example 1, the thermally conductive silicone greases prepared in Application Examples 1-4 of this application show an increase in thermal conductivity of 67.0% to 76.3%, a decrease in thermal resistance of 42.3% to 50.5%, and a significant increase in cone penetration.

[0056] As can be seen from the cone penetration measurement data in Table 2, the introduction of surface treatment agents is a key factor in improving the workability of silicone paste. A higher cone penetration results in better softness and flowability of the silicone paste, allowing it to better fill the microscopic gaps between thermal interfaces, thereby helping to reduce contact thermal resistance during assembly. The propyltrimethoxysilane oligomer provided by this invention significantly improves thermal conductivity while effectively enhancing the workability of the paste.

[0057] Comparing Application Examples 1 through 4, it can be seen that the oligomers prepared with different hydrolysis ratios affect the properties of silicone paste. Although different oligomer structures slightly adjust the properties, all samples treated with the oligomers of this invention show significantly better key properties than the untreated blank control, fully demonstrating the universality and efficiency of the technical solution of this invention.

[0058] The basic principles, main features, and advantages of this application have been described above. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely the principles of this application. Various changes and modifications can be made without departing from the spirit and scope of this application, and all such changes and modifications fall within the scope of the claimed application. The scope of protection claimed by this application is defined by the appended claims and their equivalents. This invention relates to the field of thermally conductive interface materials technology, and discloses a high thermal conductivity silicone paste with a propyltrimethoxysilane oligomer surface treatment and its preparation method. The method includes: first preparing a propyltrimethoxysilane oligomer, then mixing it with vinyl silicone oil, and finally mixing it with alumina filler under vacuum conditions to obtain the silicone paste. Using propyltrimethoxysilane oligomer to surface treat the alumina filler significantly improves the overall performance of the silicone paste. Compared to untreated samples, the use of propyltrimethoxysilane oligomers resulted in a more than 70% increase in thermal conductivity and a reduction of approximately 50% in thermal resistance in 70 vol% alumina-filled silicone paste, along with a significant increase in cone penetration. This yielded a low-cost, high-thermal-conductivity, and low-thermal-resistance thermal interface material. The preparation method of this invention is simple and easily scalable for industrial production.

[0059] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0060] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A thermally conductive silicone grease treated with propyltrimethoxysilane oligomers, characterized in that: The thermally conductive silicone grease is made from the following components in parts by weight: (1) Vinyl silicone oil: 100 parts by weight; (2) Alumina filler: 880-1020 parts by weight; (3) Propyltrimethoxysilane oligomer, the amount of which is 1.5-2.5 wt% of alumina filler.

2. The thermally conductive silicone grease treated with propyltrimethoxysilane oligomers according to claim 1, characterized in that, The density of the vinyl silicone oil and propyltrimethoxysilane oligomer is 0.96 g / cm³. 3 Calculations show that the density of the alumina filler is 4.0 g / cm³. 3 Calculations show that the volume fraction of alumina filler in the thermal conductive silicone grease is 65%~75%, the amount of propyltrimethoxysilane oligomer is 2.0 wt% of the mass of alumina filler, and the volume fraction of alumina filler in the thermal conductive silicone grease is 70%.

3. A method for preparing a thermally conductive silicone grease treated with propyltrimethoxysilane oligomers as described in claim 1, characterized in that, The specific steps are as follows: The product was prepared using vinyl silicone oil with a dynamic viscosity of 100 mPa·s at 25 °C as the matrix, alumina as the thermally conductive filler, and propyltrimethoxysilane oligomer as the surface treatment agent for the alumina thermally conductive filler, after high-speed dispersion and degassing.

4. The method for preparing the thermally conductive silicone grease treated with propyltrimethoxysilane oligomers according to claim 3, characterized in that, The alumina filler has a particle size of 70 μm.

5. The method for preparing the thermally conductive silicone grease treated with propyltrimethoxysilane oligomers according to claim 3, characterized in that, The propyltrimethoxysilane oligomer was prepared using the following steps: (1) Add propyltrimethoxysilane and methanol solvent to a three-necked flask equipped with a reflux condenser, thermometer and stirring device; (2) Heat the mixture to 35-50 °C with stirring, and then add the pre-prepared mixed solution of methanol, hydrochloric acid and water dropwise into the flask; after the mixed solution is added, raise the temperature to carry out the aging reaction; (3) After the aging reaction is complete, and the temperature of the mixture drops to room temperature, adjust the pH of the mixture to 7-8 with sodium bicarbonate; then filter and collect the filtrate. (4) Under normal pressure, the filtrate after filtration is heated at a rate of 5~10 °C / min until all the solvent is evaporated; after the mixture is cooled to room temperature, the propyltrimethoxysilane oligomer is obtained.

6. The method for preparing the thermally conductive silicone grease treated with propyltrimethoxysilane oligomers according to claim 5, characterized in that, In step (1), the mass ratio of methanol to propyltrimethoxysilane is (1 / 3~1):

1.

7. The method for preparing the thermally conductive silicone grease treated with propyltrimethoxysilane oligomers according to claim 5, characterized in that, In step (2), the mass ratio of methanol to water in the mixed solution is (1~3):1, the mass of hydrochloric acid is 1%~8% of the mass of propyltrimethoxysilane, the molar ratio of water to propyltrimethoxysilane is (0.3~2.1):1, and the time for adding the mixed solution is 10~60 min.

8. The method for preparing the thermally conductive silicone grease treated with propyltrimethoxysilane oligomers according to claim 5, characterized in that, In step (3), the aging reaction temperature is 60~90 ℃ and the aging reaction time is 2~10 hours.

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