Preparation method of heat-conducting silicone grease with extremely low oil yield

Abstract

The invention provides a preparation method of heat-conducting silicone grease with extremely low oil yield, and belongs to the technical field of heat-conducting silicone grease production.The preparation method comprises the following steps that S1, silicone oil and a treating agent are mixed; s2, mixing and stirring the heat-conducting filler; and S3, grinding. By adopting a special preparation process, the structure of the heat-conducting silicone grease is effectively optimized by accurately controlling the ratio of the silicone oil to the treating agent, the type and particle size of the filler and the process parameters of stirring and grinding, so that the heat-conducting efficiency of the heat-conducting silicone grease is remarkably improved; the product prepared by the invention has extremely low oil yield, and the heat-conducting silicone grease has no oil separation phenomenon on the surface under the storage condition of 25 DEG C for 12 months, so that the common oil outlet problem of the heat-conducting silicone grease is avoided, the heat dissipation performance can be improved, and the attenuation of the material performance in the use process can also be avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of thermal conductive silicone grease production, in particular to a method for preparing thermal conductive silicone grease with extremely low oil output. Background Art

[0002] In order to solve the problem that the existing electronic devices and processors generate too much heat during high-frequency operation, which leads to an increase in power density and affects the performance and stability of the equipment, the existing technology effectively achieves heat conduction and heat dissipation by applying thermal grease on the surface of the processor and installing a heat sink. The thermal grease reduces the thermal resistance between the processor and the heat sink through good contact with the heat sink, improves the heat dissipation effect, and ensures that the temperature of the processor is effectively controlled when running at high speed. However, existing thermal grease products generally have problems such as easy oiling, high temperature resistance, and easy cracking under hot and cold cycles. This leads to a gradual decline in the heat dissipation effect over time, and even the occurrence of heat insulation, which affects the long-term stability of electronic devices.

[0003] In order to overcome this problem, the market has proposed solutions to replace traditional silicone grease with cross-linked thermal conductive gels, thermal conductive gaskets, phase change materials, etc. However, these alternative materials still have the potential risk of being difficult to process, difficult to construct, and having performance degradation during use. Summary of the invention

[0004] The purpose of the present invention is to solve the above problems in the prior art and to provide a method for preparing thermally conductive silicone grease with extremely low oil output.

[0005] The purpose of the present invention can be achieved by the following technical scheme: A method for preparing thermally conductive silicone grease with extremely low oil output, the method for preparing thermally conductive silicone grease with extremely low oil output specifically comprises the following steps:

[0006] S1. Mixing silicone oil and treatment agent: Stir and mix silicone oil and treatment agent evenly to obtain an initial mixture;

[0007] The silicone oil is at least one of dimethyl silicone oil, phenyl methyl silicone oil, polyether modified silicone oil, acrylate modified silicone oil, hydroxy silicone oil, and amino silicone oil.

[0008] The treating agent is at least one of a silane coupling agent, an alkyl methoxy / ethoxy silicone oil, a vinyl methoxy / ethoxy silane, and a methyl methoxy / ethoxy silane.

[0009] S2 Mixing and stirring of thermal conductive filler: Add thermal conductive filler to the initial mixture, and then use a specific stirring process to perform initial stirring, first vacuum stirring and second vacuum stirring operations in sequence to obtain an intermediate mixture.

[0010] In the initial stirring operation, the stirring temperature is 60-100°C; in the first vacuum stirring operation, the stirring temperature is 120-160°C; in the second vacuum stirring operation, the stirring temperature is 160-200°C;

[0011] The thermal conductive filler is at least one of angular / spherical / quasi-spherical / single-crystal alumina, spherical aluminum powder, needle-shaped / spherical zinc oxide, hexagonal / rhombic / cubic boron nitride, single-layer / few-layer graphene, light / heavy calcium carbonate, silicon dioxide prepared by vapor phase method / precipitation method, and spherical / flaky aluminum hydroxide.

[0012] The morphology and size parameters of thermal conductive fillers are as follows: angular / spherical / quasi-spherical / single crystal alumina: 0.5-10μm; spherical aluminum powder: 1-10μm; needle-shaped / spherical zinc oxide: 0.1-1μm; hexagonal / rhombic / cubic boron nitride: 0.2-10μm 2 ; Single / few-layer graphene: 0.05-1μm 2 ; Light / heavy calcium carbonate: 300-3000 mesh; Silicon dioxide prepared by gas phase method / precipitation method: 1-10μm; Spherical / flaky aluminum hydroxide: 1-20μm; S3 grinding: The intermediate mixed material is subjected to coarse grinding and fine grinding operations in sequence to obtain thermal grease with extremely low oil output;

[0013] Preferably, in step S1, the weight ratio of silicone oil to treatment agent is 5-40:1.

[0014] Preferably, in step S2, the weight ratio of the initial mixture to the thermally conductive filler is 1:5-30.

[0015] Preferably, in step S3, a three-roll grinder is used as the grinding equipment, and the coarse grinding operation parameters are as follows: the front roller spacing is 30-40um, and the rear roller spacing is adjusted to 20-25um; the fine grinding operation parameters are as follows: the front roller spacing is 12-18um, and the rear roller spacing is 8-13um.

[0016] Preferably, in step S1, the initial stirring time is 1-4 hours.

[0017] Preferably, in step S1, the first vacuum stirring time is 1-4 hours, the vacuum degree is not higher than 0.09 MPa, and after the stirring is completed, the air release valve is opened first, and then the edge and bottom scraping operations are performed.

[0018] Preferably, in step S1, the second vacuum stirring time is 1-4 hours, and the vacuum degree is not higher than 0.09 MPa.

[0019] Preferably, in step S3, the grinding speed of the coarse grinding operation is 100-150 rpm.

[0020] Preferably, in step S3, the grinding speed of the fine grinding operation is 150-200 rpm.

[0021] Preferably, in step S1, the stirring device used is a planetary stirring device or a kneading stirring device.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The special preparation process adopted by the present invention effectively optimizes the structure of the thermal grease by precisely controlling the ratio of silicone oil to treatment agent, the type and particle size of filler, and the process parameters of stirring and grinding, so that its thermal conductivity efficiency is significantly improved. This can not only improve the heat dissipation performance, but also avoid the attenuation of material performance during use.

[0024] The thermally conductive silicone grease with extremely low oil output produced by the preparation method of the present invention is superior to the prior art in many aspects. First of all, the thermally conductive silicone grease has extremely high thermal stability and long-term use stability. During storage, the silicone grease will not have significant oil output, and can effectively prevent oil output in a high temperature environment, avoiding the common performance degradation problem of traditional thermally conductive silicone grease under high temperature or long-term use. Even after repeated changes in high and low temperature cycles, the thermally conductive silicone grease of the present invention can still maintain the same physical properties as the initial construction state, ensuring the stability of its long-term heat dissipation performance. Therefore, the thermally conductive silicone grease provided by the present invention can effectively solve the degradation of thermal conductivity and heat insulation caused by oil output or temperature changes in the prior art, thereby improving the long-term stability and reliability of electronic devices and processors.

[0025] In summary, the extremely low oil-yield thermal grease of the present invention has significant thermal stability, long-term heat dissipation performance and reliability, solves the common oil-yield and performance degradation problems of existing thermal greases under high temperature and high power density, and provides a more stable and efficient solution for the heat dissipation of electronic devices. DETAILED DESCRIPTION

[0026] The following are specific embodiments of the present invention, which further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments. Specific embodiment:

[0028] A method for preparing thermally conductive silicone grease with extremely low oil output, specifically comprising the following steps:

[0029] S1 selects raw materials: (1) The selected silicone oil is dimethyl silicone oil with a viscosity of 500; (2) The selected treatment agent is vinyl triethoxy silane; (3) The thermal conductive filler is spherical alumina with a particle size of 10um, 3um, and 0.7um, and is also matched with zinc oxide with a particle size of 0.1um, and the mass ratios are 12:5:1:3 respectively.

[0030] S2 Preparation process: S2.1 Process 1: Add 200g of raw material (1) and 10g of raw material (2) to the cylinder of a 5L planetary mixer, and stir at 15rpm for 5 minutes. Then add 2000g of raw material (3), stir at 20rpm and 80℃ for 1 hour, and scrape the sides and bottom after completion; continue stirring under the above conditions for 1 hour, and scrape the sides and bottom after completion;

[0031] Then the temperature was controlled at 150°C, vacuum was started, the vacuum degree was controlled below 0.09 MPa, the planetary stirring speed was set to 25 rpm, stirring was performed for 2 hours, and after completion, the air release valve was opened first, and then the side and bottom scraping operations were performed; finally, the temperature was controlled at 170°C, the vacuum degree was controlled below 0.09 MPa, the planetary stirring speed was set to 30 rpm, stirring was performed for 2 hours, and the mixture was cooled to room temperature to obtain the primary product A.

[0032] S2.2 Process 2: Grind the primary product A with a three-roller grinder, adjust the front roller spacing to 40um, the rear roller spacing to 25um, and the grinding speed to 150rpm, and grind the primary product A once; then adjust the front roller spacing to 18um, the rear roller spacing to 12um, and the grinding speed to 200rpm, and grind the primary product A again. Finally, the target extremely low oil output thermal grease is obtained.

[0033] Comparative Example: A method for preparing thermally conductive silicone grease, specifically comprising the following steps:

[0034] S1 selects raw materials: (1) The selected silicone oil is dimethyl silicone oil with a viscosity of 500; (2) The thermal conductive filler is spherical alumina with a particle size of 10um, 3um, and 0.7um, and zinc oxide with a particle size of 0.1um, and the mass ratio is 12:5:1:3 respectively.

[0035] S2: Preparation process: S2.1 Process 1: Add 210g of raw material (1) and 2000g of raw material (2) to the cylinder of a 5L planetary mixer, stir at 20rpm and 80℃ for 1 hour, and scrape the sides and bottom after completion; continue stirring under the above conditions for 1 hour, and scrape the sides and bottom after completion; then control the temperature at 150℃, start vacuuming, control the vacuum degree at less than 0.09MPa, set the planetary stirring speed to 25rpm, stir for 2 hours, open the air release valve after completion, and then scrape the sides and bottom; finally control the temperature at 170℃, control the vacuum degree at less than 0.09MPa, set the planetary stirring speed to 30rpm, and stir for 2 hours. Cool to room temperature to obtain primary product A.

[0036] S2.2 Process 2: Grind the primary product A with a three-roller grinder, adjust the front roller spacing to 40um, the rear roller spacing to 25um, and the grinding speed to 150rpm. Grind the primary product A once;

[0037] Then the front roller spacing was adjusted to 18um, the rear roller spacing was adjusted to 12um, the grinding speed was 200rpm, and the primary product A was ground again. Finally, the target thermal conductive silicone grease was obtained.

[0038] The extremely low oil output thermal grease prepared in the specific example and the thermal grease prepared in the comparative example were subjected to performance tests, and the test results are shown in Table 1:

[0039]

[0040] Table 1

[0041] Result analysis: The embodiment uses vinyl triethoxysilane as a treatment agent, which effectively reduces the interaction between the thermal conductive filler and the silicone oil, so that it forms a more uniform and stable structure during the mixing process, and inhibits oil separation. This feature is particularly important because it reduces the oil separation problem of thermal conductive silicone grease during long-term use.

[0042] Combined with the test data, the effects of the product prepared by the present invention are described:

[0043] Extremely low oil release: The oil release rate is 0.05%, which is a major advantage. Usually, traditional thermal grease is prone to oil release in long-term use or high temperature environment, resulting in performance degradation and reduced heat dissipation effect. However, under the storage conditions of 25°C and 12 months, there is no oil separation on the surface of this thermal grease, indicating that it has very low oil release. This enables the product to maintain good heat dissipation effect in high temperature and high power density environment, avoiding the common "oil release" problem of thermal grease.

[0044] Excellent thermal stability: The thermally conductive silicone grease of the present invention has high thermal stability, and its thermal conductivity will not be significantly affected even when used at higher temperatures. Through vacuum treatment, the bubbles and volatile components in the raw materials are reduced, thereby reducing the risk of poor thermal stability. It can effectively prevent oil from coming out in high temperature environments, and exhibits excellent heat resistance and thermal conductivity.

[0045] High thermal conductivity: The thermal conductivity is 3.35W / m·K, which shows that the thermal grease has high thermal conductivity and helps dissipate heat from electronic devices and processors. Compared with traditional thermal grease, the higher thermal conductivity can more effectively transfer heat from the heat source to the radiator or other cooling components, ensuring the normal operating temperature of electronic devices and processors, and avoiding overheating and performance degradation or damage.

[0046] Long-term use stability: When the thermal grease is stored at room temperature for 12 months, the surface can maintain no oil precipitation. This shows that it has very good physical and chemical stability, and can maintain its physical properties in long-term use, avoiding performance degradation caused by temperature fluctuations or long-term loads. Traditional thermal grease may precipitate oil during storage, resulting in hardening of the coating or reduction of thermal conductivity, but the present invention can effectively prevent these problems and ensure long-term stability.

[0047] High-performance filler design: Aluminum oxide (10μm, 3μm, 0.7μm) and zinc oxide (0.1μm) of different particle sizes are used. This filler combination helps optimize thermal conductivity. Aluminum oxide and zinc oxide play a role in enhancing thermal conductivity in thermal grease. At the same time, due to the different particle sizes, they can provide a more uniform heat conduction channel, which helps to improve the overall heat dissipation performance.

[0048] Fine preparation process: A combination of planetary stirring and three-roll mill is used in the preparation process. Through specific stirring industry and grinding process, the aggregation between particles can be effectively avoided, and the dispersion of fillers in silicone grease can be improved, thereby improving the thermal conductivity and stability of silicone grease. By adjusting the distance between the front and rear rollers and the grinding speed, the dispersion uniformity of the particles can be further improved, thereby enhancing the performance of the final product.

[0049] Practical advantages of application: The thermal conductive silicone grease of the present invention has extremely low oil release, good thermal stability and long-term use stability. It can effectively improve the heat dissipation efficiency of electronic devices and processors, and is particularly suitable for electronic devices in high power density and high temperature environments. With the continuous improvement of the performance of modern electronic devices, their requirements for heat dissipation are also getting higher and higher, especially when used for a long time or under high load. The advantage of this type of thermal conductive silicone grease is that it can work stably for a long time, ensuring the stability and reliability of electronic equipment.

[0050] Through the above analysis, it can be seen that the extremely low oil-yielding thermal grease of the present invention has many advantages over the existing technology, especially in terms of thermal stability, long-term use stability and thermal conductivity. These advantages make it particularly suitable for use in high-performance electronic devices that require long-term stable heat dissipation, and can effectively solve the common oil-yielding and performance degradation problems of traditional thermal grease under high temperature or long-term use, and improve the long-term stability and reliability of electronic equipment.

[0051] The specific embodiments described herein are merely examples of the spirit of the present invention. A person skilled in the art of the present invention may make various modifications or supplements to the specific embodiments described or replace them in a similar manner, but will not deviate from the spirit of the present invention or exceed the defined scope. Although the present invention is described and described in detail in the foregoing description, such descriptions and descriptions are considered to be illustrative or exemplary rather than restrictive. It should be understood that within the scope of the following claims, changes and modifications may be made by a person of ordinary skill. Specifically, the present invention encompasses additional embodiments having any combination of features from the above-mentioned different embodiments. With respect to the use of the expression "generally" or "substantially", this patent application should be understood to disclose that these features and values ​​are also fully satisfied, i.e., there is no aforementioned characterization as "generally" or "substantially".

Claims

1. A method for preparing thermally conductive silicone grease with extremely low oil output, characterized in that: The preparation method of extremely low oil output thermal conductive silicone grease specifically comprises the following steps: S1. Mixing silicone oil and treatment agent: Stir and mix silicone oil and treatment agent evenly to obtain an initial mixture; The silicone oil is at least one of dimethyl silicone oil, phenyl methyl silicone oil, polyether modified silicone oil, acrylate modified silicone oil, hydroxy silicone oil, and amino silicone oil. The treating agent is at least one of a silane coupling agent, an alkyl methoxy / ethoxy silicone oil, a vinyl methoxy / ethoxy silane, and a methyl methoxy / ethoxy silane. S2 Mixing and stirring of thermal conductive filler: Add thermal conductive filler to the initial mixture, and then use a specific stirring process to perform initial stirring, first vacuum stirring and second vacuum stirring operations in sequence to obtain an intermediate mixture. In the initial stirring operation, the stirring temperature is 60-100°C; in the first vacuum stirring operation, the stirring temperature is 120-160°C; in the second vacuum stirring operation, the stirring temperature is 160-200°C; The thermal conductive filler is at least one of angular / spherical / quasi-spherical / single-crystal alumina, spherical aluminum powder, needle-shaped / spherical zinc oxide, hexagonal / rhombic / cubic boron nitride, single-layer / few-layer graphene, light / heavy calcium carbonate, silicon dioxide prepared by vapor phase method / precipitation method, and spherical / flaky aluminum hydroxide. The morphology and size parameters of thermal conductive fillers are as follows: angular / spherical / quasi-spherical / single crystal alumina: 0.5-10μm; spherical aluminum powder: 1-10μm; needle-shaped / spherical zinc oxide: 0.1-1μm; hexagonal / rhombic / cubic boron nitride: 0.2-10μm 2 ; Single / few-layer graphene: 0.05-1μm 2 ; Light / heavy calcium carbonate: 300-3000 mesh; Silicon dioxide prepared by gas phase method / precipitation method: 1-10μm; Spherical / flaky aluminum hydroxide: 1-20μm; S3 grinding: The intermediate mixed material is subjected to coarse grinding and fine grinding operations in sequence to obtain a thermal grease with extremely low oil output.

2. The method for preparing the thermally conductive silicone grease with extremely low oil yield as claimed in claim 1, wherein in step S1, the weight ratio of silicone oil to treatment agent is 5-40:

1.

3. The method for preparing the extremely low oil yield thermally conductive silicone grease according to claim 1, wherein in step S2, the weight ratio of the initial mixture to the thermally conductive filler is 1:5-30.

4. The method for preparing the thermal grease with extremely low oil output as claimed in claim 1, wherein in step S3, a three-roll grinder is used as the grinding equipment, and the coarse grinding operation parameters are as follows: the front roller spacing is 30-40um, and the rear roller spacing is adjusted to 20-25um; the fine grinding operation parameters are as follows: the front roller spacing is 12-18um, and the rear roller spacing is 8-13um.

5. The method for preparing the extremely low oil output thermal grease according to claim 1, characterized in that: In step S1, the initial stirring time is 1-4 hours.

6. The method for preparing the extremely low oil output thermal grease according to claim 1, characterized in that: In step S1, the first vacuum stirring time is 1-4 hours, the vacuum degree is not higher than 0.09 MPa, and after the stirring is completed, the air release valve is opened first, and then the edge and bottom scraping operations are performed.

7. The method for preparing the extremely low oil output thermal conductive silicone grease according to claim 1, characterized in that: In step S1, the second vacuum stirring time is 1-4 hours, and the vacuum degree is not higher than 0.09 MPa.

8. The method for preparing the extremely low oil output thermal conductive silicone grease according to claim 1, characterized in that: In step S3, the grinding speed of the rough grinding operation is 100-150 rpm.

9. The method for preparing the extremely low oil output thermal conductive silicone grease according to claim 1, characterized in that: In step S3, the grinding speed of the fine grinding operation is 150-200 rpm.

10. The method for preparing the thermally conductive silicone grease with extremely low oil yield as claimed in claim 1, wherein in step S1, the stirring device used is a planetary stirring device or a kneading stirring device.

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