A low-cost, high-performance thermal conductive silicone grease and its preparation method and application

Abstract

The present invention provides a low-cost, high-performance thermally conductive silicone grease and its preparation method and application. The thermally conductive silicone grease of the present invention includes the following raw materials in mass fractions: silicone oil: 1-200 parts, thermally conductive filler A: 0-1000 parts, thermally conductive filler B: 0-1000 parts, thermally conductive filler C: 1-500 parts, thermally conductive filler D: 1-500 parts, thermally conductive filler E: 0-200 parts, thermally conductive filler F: 0-200 parts, coupling agent: 1-20 parts. The thermally conductive silicone grease of the present invention has high thermal conductivity, moderate viscosity, excellent thixotropy and low oil permeability, showing good comprehensive performance, and simple preparation process, cheap raw materials, easy to obtain and no special treatment is required, and low production cost. The thermal conductivity of the thermally conductive silicone grease of the present invention can reach 8.50W / m·K, has excellent thermal conductivity, and can meet the growing market demand.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal interface materials, and in particular to a low-cost, high-performance thermal conductive silicone grease and a preparation method and application thereof. Background Art

[0002] With the miniaturization and integration of electronic products, the requirements for heat dissipation of electronic components are getting higher and higher. The high operating temperature of components will reduce the life and performance of the equipment. Thermal conductive silicone grease can effectively reduce the operating temperature of components and improve the stability and reliability of equipment by enhancing the heat conduction between the heat source and the heat sink. It is widely used in the thermal management system of electronic equipment.

[0003] Thermally conductive fillers are a key factor in determining the performance of thermal grease. Currently, thermally conductive greases with high thermal conductivity mostly use high thermal conductive fillers such as graphite powder and carbon nanotubes. However, the preparation process of these materials is complex, expensive, and has limited insulation properties. In addition, such materials also face challenges when achieving high filling amounts. Some thermal greases increase thermal conductivity by increasing the filling amount of thermally conductive fillers, but this method often leads to a significant increase in the viscosity of the thermal grease, making the coating process difficult and prone to drying, cracking and other problems. To improve wettability, some thermal greases use modified organic silanes or surface treat the fillers, but these methods usually require special modification processes, which are complex and costly, making them difficult to promote widely.

[0004] Therefore, it is particularly important to develop a thermal grease with high thermal conductivity, low cost and excellent comprehensive performance to meet the growing market demand. This type of thermal grease not only needs to make breakthroughs in thermal conductivity, but also needs to take into account viscosity control, insulation performance and simplified preparation process to truly meet the application needs of electronic equipment, optoelectronic devices and other fields. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a low-cost, high-performance thermally conductive silicone grease and a preparation method and application thereof. On the one hand, the thermally conductive silicone grease of the present invention has high thermal conductivity, moderate viscosity, excellent thixotropy and low oil permeability, showing good comprehensive performance. On the other hand, the preparation process is simple, the raw materials used are cheap and easy to obtain and do not require special treatment, and the production cost is low. Compared with the common thermally conductive silicone grease with a thermal conductivity of 6W / m·K on the market, the thermally conductive silicone grease of the present invention has a thermal conductivity of up to 8.50W / m·K, has excellent thermal conductivity, and can meet the growing market demand.

[0006] The technical solution of the present invention is as follows:

[0007] A low-cost, high-performance thermal conductive silicone grease is prepared by including the following raw materials in parts by weight:

[0008] Silicone oil: 1-200 parts, thermal conductive filler A: 0-1000 parts, thermal conductive filler B: 0-1000 parts, thermal conductive filler C: 1-500 parts, thermal conductive filler D: 1-500 parts, thermal conductive filler E: 0-200 parts, thermal conductive filler F: 0-200 parts, coupling agent: 1-20 parts.

[0009] Preferably, according to the present invention, the low-cost high-performance thermal conductive silicone grease is prepared by including the following raw materials in parts by weight:

[0010] Silicone oil: 80-100 parts, thermal conductive filler A: 500-700 parts, thermal conductive filler C: 200-300 parts, thermal conductive filler D: 100-200 parts, thermal conductive filler E: 0-100 parts, thermal conductive filler F: 0-100 parts, coupling agent: 15-20 parts.

[0011] Preferably, the low-cost high-performance thermal conductive silicone grease is prepared by including the following raw materials in parts by weight:

[0012] Silicone oil: 80-100 parts, thermal conductive filler A: 590-610 parts, thermal conductive filler C: 230-250 parts, thermal conductive filler D: 150-170 parts, thermal conductive filler E: 90-110 parts, thermal conductive filler F: 90-110 parts, coupling agent: 17-18 parts.

[0013] Preferably, the low-cost high-performance thermal conductive silicone grease is prepared by including the following raw materials in parts by weight:

[0014] Silicone oil: 80-100 parts, thermal conductive filler A: 590-610 parts, thermal conductive filler C: 230-250 parts, thermal conductive filler D: 150-170 parts, coupling agent: 17-18 parts.

[0015] Further preferably, the low-cost high-performance thermal conductive silicone grease is prepared by including the following raw materials in parts by weight:

[0016] Silicone oil: 90 parts, thermal conductive filler A: 600 parts, thermal conductive filler C: 240 parts, thermal conductive filler D: 160 parts, thermal conductive filler E: 100 parts, thermal conductive filler F: 100 parts, coupling agent: 17.5 parts.

[0017] Further preferably, the low-cost high-performance thermal conductive silicone grease is prepared by including the following raw materials in parts by weight:

[0018] Silicone oil: 90 parts, thermal conductive filler A: 600 parts, thermal conductive filler C: 240 parts, thermal conductive filler D: 160 parts, coupling agent: 17.5 parts.

[0019] Preferably according to the present invention, the silicone oil is one or a combination of two or more of dimethyl silicone oil, hydrogen silicone oil, benzyl silicone oil, hydroxy silicone oil or vinyl silicone oil; the viscosity of the silicone oil at 25° C. ranges from 100 to 2000 mPa·s.

[0020] Preferably according to the present invention, thermally conductive fillers A, B, C, D, E, and F are each selected from one or a combination of two or more of aluminum oxide, zinc oxide, boron nitride, silicon nitride, silicon dioxide, aluminum powder, copper powder, aluminum nitride, or diamond; and thermally conductive fillers A, B, C, D, E, and F are the same or different.

[0021] Preferably according to the present invention, the D50 particle size of thermally conductive filler A is: 100μm≤D50≤200μm, the D50 particle size of thermally conductive filler B is: 20μm≤D50<100μm, the D50 particle size of thermally conductive filler C is: 5μm≤D50<20μm, the D50 particle size of thermally conductive filler D is: 2.5μm≤D50<5μm, the D50 particle size of thermally conductive filler E is: 1μm≤D50<2.5μm, and the D50 particle size of thermally conductive filler F is: 50nm≤D50≤200nm.

[0022] Preferably according to the present invention, the shape of the thermally conductive fillers A, B, C, D, E, and F is a spherical shape, a spherical shape, or a sheet shape, or a combination of two or more thereof.

[0023] Preferably, according to the present invention, the coupling agent is a silane coupling agent; preferably, the coupling agent is one or a combination of two or more of propyltrimethoxysilane, decyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane or γ-aminopropyltriethoxysilane.

[0024] The method for preparing the above-mentioned low-cost and high-performance thermal conductive silicone grease comprises the following steps:

[0025] Silicone oil, coupling agent, thermal conductive filler A, thermal conductive filler B, thermal conductive filler C, thermal conductive filler D, thermal conductive filler E and thermal conductive filler F are fully stirred and mixed evenly; then, low-cost and high-performance thermal conductive silicone grease is obtained by grinding and fully stirring and mixing.

[0026] According to the preferred embodiment of the present invention, the method for preparing low-cost high-performance thermal conductive silicone grease comprises the following steps:

[0027] S1. Add silicone oil and coupling agent into a planetary centrifugal mixer;

[0028] S2. Add thermal conductive filler A, thermal conductive filler B, thermal conductive filler C, thermal conductive filler D, thermal conductive filler E, and thermal conductive filler F to a planetary centrifugal mixer in sequence, stirring for 5-15 minutes after each addition of a filler;

[0029] S3. The mixture obtained in step S2 above was transferred to a three-roll mill and ground 1-3 times;

[0030] S4. The mixture obtained by grinding in the above step S3 is transferred from the three-roll grinder to a planetary centrifugal mixer, and stirred for 20-30 minutes under a vacuum environment; finally, low-cost and high-performance thermal conductive silicone grease is obtained.

[0031] Preferably, the stirring rate in S2 is 800-1600 r / min;

[0032] Preferably, the stirring rate in S4 is 1000-2000 / min, and the vacuum degree is maintained at -0.092 to -0.098 MPa.

[0033] The above-mentioned low-cost, high-performance thermal grease is used in the heat dissipation of electronic components.

[0034] The technical features and beneficial effects of the present invention are as follows:

[0035] The present invention mainly adds large-particle thermal conductive filler A, and utilizes its large contact area to better bridge the gaps between thermal conductive fillers to form an efficient heat conduction path, thereby effectively reducing contact thermal resistance and improving overall thermal conductivity. Compared with small-particle fillers, large-particle fillers have lower specific surface area and interface interaction force, which can prevent the viscosity of silicone grease from being too high, while optimizing thixotropy, thereby maintaining its good coating and operability. In addition, large-particle filler A is simple to prepare, easy to obtain and inexpensive, which greatly reduces the preparation cost of thermal conductive silicone grease.

[0036] The present invention accurately designs the ratio of thermally conductive fillers with multi-level particle sizes, so that the fillers can adaptively fill the air gaps and form a denser thermal conductive network in the silicone oil, thereby significantly reducing the thermal resistance of the product and greatly improving the thermal conductivity. While ensuring a high filling rate, the product still maintains a suitable viscosity and thixotropy. The particle size of the thermally conductive filler, the ratio between the fillers and their dosage are key factors affecting the performance of the present invention. If the particle size is not properly selected or matched, the filler is not easy to disperse, and the gap cannot be effectively filled, the thermal conductive path will be discontinuous, resulting in an increase in thermal resistance, thereby reducing the thermal conductivity. At the same time, an inappropriate filler ratio will cause the thermally conductive filler to be unevenly distributed in the thermally conductive silicone grease, resulting in a thermal "short circuit" or "open circuit", which significantly weakens the thermal conductivity effect. In addition, excessive filler dosage will make the viscosity of the thermally conductive silicone grease too high, and the silicone oil cannot fully fill the filler gap, affecting the fluidity and thermal conductivity of the material; insufficient filler dosage will not form a sufficient thermal conductive path, resulting in a decrease in thermal conductivity efficiency.

[0037] The preparation process of the invention is simple, the operation is convenient, and the selected raw materials are easily available and inexpensive, which helps to significantly improve the overall performance of the product under the premise of controllable cost, is suitable for large-scale production and meets market demand. The selection of raw materials directly affects the thermal conductivity, mechanical properties, temperature resistance and cost of silicone grease. If the raw materials are not selected properly, the thermal stability and durability of the silicone grease will be reduced, thereby affecting the operability and safety of the final product.

[0038] The core of the present invention is to accurately control the particle size, ratio and dosage of the thermally conductive filler, combine reasonable raw material selection and matching, and optimize the preparation process to produce thermally conductive silicone grease with high thermal conductivity and excellent comprehensive performance at a relatively low cost. By optimizing these key conditions, the present invention can still obtain a thermally conductive silicone grease with a thermal conductivity of up to 8.50W / m·K through a conventional preparation process without adding high thermally conductive fillers such as graphite powder and carbon nanotubes. The thermally conductive silicone grease not only has excellent thermal conductivity, but also has suitable fluidity and thixotropy, low oil permeability, moderate viscosity, and is not prone to drying and cracking problems, showing extremely high application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a picture showing the effect of applying the thermal conductive silicone grease prepared in Example 1 of the present invention on a heat generating chip. DETAILED DESCRIPTION

[0040] The present invention will be further described below with reference to the embodiments.

[0041] Unless otherwise specified, the reagents and equipment used in the examples are commercially available; the methods used are all existing methods unless otherwise specified.

[0042] Example 1

[0043] A low-cost, high-performance thermal conductive silicone grease is prepared by including the following raw materials in parts by weight:

[0044] Dimethyl silicone oil (viscosity at 25°C is about 500mPa·s): 90 parts, thermally conductive filler A (spherical aluminum powder, D50 is 200μm): 600 parts, thermally conductive filler C (spherical aluminum powder, D50 is 8μm): 240 parts, thermally conductive filler D (spherical aluminum powder, D50 is 3μm): 160 parts, thermally conductive filler E (spherical aluminum powder, D50 is 1μm): 100 parts, thermally conductive filler F (spherical aluminum powder, D50 is 100nm): 100 parts, coupling agent (propyltrimethoxysilane): 17.5 parts.

[0045] The method for preparing the above-mentioned low-cost and high-performance thermal conductive silicone grease comprises the following steps:

[0046] S1. Pour dimethyl silicone oil and siloxane coupling agent into a planetary centrifugal mixer;

[0047] S2. The thermally conductive filler A, thermally conductive filler C, thermally conductive filler D, thermally conductive filler E, thermally conductive filler F were sequentially added to a planetary centrifugal mixer, and each filler was stirred at a speed of 1200 rpm / min for 5 min;

[0048] S3. The mixture obtained in step S2 above was transferred from a planetary centrifugal mixer to a three-roll mill and ground twice;

[0049] S4. The mixture obtained by grinding in the above step S3 is transferred from the three-roll grinder to a planetary centrifugal mixer, and stirred for 20 minutes at a speed of 1600 rpm / min under a vacuum environment (the vacuum degree is maintained at -0.092 to -0.098 MPa); finally, low-cost and high-performance thermal grease is obtained.

[0050] Example 2

[0051] A low-cost, high-performance thermal conductive silicone grease is prepared by including the following raw materials in parts by weight:

[0052] Dimethyl silicone oil (viscosity at 25°C is about 500 mPa·s): 90 parts, thermally conductive filler A (spherical aluminum powder, D50 is 200μm): 600 parts, thermally conductive filler C (spherical aluminum powder, D50 is 8μm): 240 parts, thermally conductive filler D (spherical aluminum powder, D50 is 3μm): 160 parts, coupling agent (propyltrimethoxysilane): 17.5 parts.

[0053] The preparation method of the above-mentioned low-cost and high-performance thermal conductive silicone grease is as described in Example 1.

[0054] Example 3

[0055] A thermally conductive silicone grease is prepared by including the following raw materials in parts by weight:

[0056] Dimethyl silicone oil (viscosity at 25°C is about 500mPa·s): 90 parts, thermally conductive filler B (spherical aluminum powder, D50 is 20μm): 600 parts, thermally conductive filler C (spherical aluminum powder, D50 is 8μm): 240 parts, thermally conductive filler D (spherical aluminum powder, D50 is 3μm): 160 parts, coupling agent (propyltrimethoxysilane): 17.5 parts.

[0057] The preparation method of the above thermal conductive silicone grease is as described in Example 1.

[0058] Example 4

[0059] A thermally conductive silicone grease is prepared by including the following raw materials in parts by weight:

[0060] Dimethyl silicone oil (viscosity at 25°C is about 500mPa·s): 140 parts, thermally conductive filler B (spherical aluminum powder, D50 is 20μm): 600 parts, thermally conductive filler C (spherical aluminum powder, D50 is 8μm): 350 parts, thermally conductive filler D (spherical aluminum powder, D50 is 3μm): 50 parts, coupling agent (propyltrimethoxysilane): 17.5 parts.

[0061] The preparation method of the above thermal conductive silicone grease is as described in Example 1.

[0062] Example 5

[0063] A thermally conductive silicone grease is prepared by including the following raw materials in parts by weight:

[0064] Dimethyl silicone oil (viscosity at 25°C is approximately 500 mPa·s): 90 parts, thermally conductive filler A (spherical aluminum nitride powder, D50 is 200 μm): 600 parts, thermally conductive filler C (spherical aluminum nitride powder, D50 is 8 μm): 240 parts, thermally conductive filler D (spherical aluminum nitride powder, D50 is 3 μm): 160 parts, coupling agent (propyltrimethoxysilane): 17.5 parts.

[0065] The preparation method of the above thermal conductive silicone grease is as described in Example 1.

[0066] The raw material compositions of Examples 1-5 are shown in Table 1:

[0067] Table 1 Raw material composition of Examples 1-5

[0068]

[0069] Test Example 1

[0070] The thermal conductivity, filling rate, density, viscosity, volatility, oil permeability and thixotropy of the thermally conductive silicone grease prepared in the test example are tested, and the test method is as follows:

[0071] Thermal conductivity: Tested using TIMA 5 thermal interface material analyzer in accordance with ASTM D5470.

[0072] Viscosity test: Brookfield HBDV2T viscometer, model HBDV2T, HPQA-Helipath fast lifting stand with 96 (T) rotor, tested at 25°C, taking 20r / min data.

[0073] Volatility: Tested using a steel mesh oil separation tester in accordance with HG / T 2502-1993 5201 standard.

[0074] Oil permeability: Use a steel mesh oil separation tester and refer to HG / T 2502-1993 5201 standard for testing.

[0075] Thixotropy: Use a Brookfield HBDV2T viscometer to test the viscosity at different speeds at 25°C to see if there is a significant difference in viscosity.

[0076] Filling rate: the percentage of filler mass to the total mass of thermal grease.

[0077] The performance parameters of thermal grease are shown in Table 2 below.

[0078] Table 2 Performance test data

[0079]

[0080] Note: Since the thermal conductivity of Examples 4 and 5 is not outstanding, other properties were not tested.

[0081] As can be seen from Table 2, Examples 1-2 all use large-particle thermal conductive fillers, and their thermal conductivity is significantly improved compared to Examples 3 and 4. In particular, compared with Example 3, Example 2 is significantly better than Example 3 in key properties such as thermal conductivity, viscosity and volatility, which shows that the application of large-particle fillers greatly improves the thermal conductivity of thermal grease, while improving its fluidity and volatility. In addition, compared with Example 5, the thermal conductivity of Examples 1 and 2 is significantly different, further illustrating that the selection of thermal conductive fillers is crucial to the final performance. In summary, Examples 1-2 perform well in terms of thermal conductivity, filling rate, viscosity and volatility, and are significantly better than other example samples, showing excellent thermal functional material performance. This shows that by adding large-particle fillers, accurately designing the particle size ratio and reasonably selecting raw materials, thermal conductive silicone grease with excellent thermal conductivity and mechanical properties can be prepared at a lower cost, and is suitable for application scenarios with high requirements for thermal conductivity and stability.

[0082] Test Example 2

[0083] The heat reduction effect of the thermal conductive silicone grease prepared in Example 1 on the chip was tested.

[0084] Figure 1 The infrared thermal imaging images of the heating chip without thermal grease and with thermal grease prepared in Example 1 of the present invention after the temperature is stabilized are shown. It can be found that the temperature of the heating chip with thermal grease prepared in Example 1 of the present invention drops significantly, indicating that the thermal grease prepared in Example 1 of the present invention has excellent thermal conductivity.

[0085] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A low-cost, high-performance thermal grease, characterized in that: Low-cost, high-performance thermally conductive silicone grease is prepared from the following raw materials in parts by weight: Silicone oil: 90 parts, thermal conductive filler A: 600 parts, thermal conductive filler C: 240 parts, thermal conductive filler D: 160 parts, thermal conductive filler E: 100 parts, thermal conductive filler F: 100 parts, coupling agent: 17.5 parts; The silicone oil is dimethyl silicone oil; the thermal conductive fillers A, C, D, E, and F are aluminum powder; the coupling agent is propyltrimethoxysilane; the thermal conductive fillers A, C, D, E, and F are spherical in shape; The D50 of the thermally conductive filler A is 200 μm, the D50 of the thermally conductive filler C is 8 μm, the D50 of the thermally conductive filler D is 3 μm, the D50 of the thermally conductive filler E is 1 μm, and the D50 of the thermally conductive filler F is 100 nm.

2. The low-cost, high-performance thermal grease according to claim 1, characterized in that: The viscosity of the silicone oil at 25° C. ranges from 100 to 2000 mPa·s.

3. The method for preparing the low-cost, high-performance thermal conductive silicone grease according to any one of claims 1 to 2, comprising the steps of: Silicone oil, coupling agent, thermal conductive filler A, thermal conductive filler C, thermal conductive filler D, thermal conductive filler E and thermal conductive filler F are fully stirred and mixed evenly; then, low-cost and high-performance thermal conductive silicone grease is obtained by grinding and fully stirring and mixing.

4. The method for preparing the low-cost, high-performance thermal conductive silicone grease according to claim 3 comprises the steps of: S1. Add silicone oil and coupling agent into a planetary centrifugal mixer; S2. Add thermal conductive filler A, thermal conductive filler C, thermal conductive filler D, thermal conductive filler E, and thermal conductive filler F to a planetary centrifugal mixer, stirring for 5-15 minutes for each addition of a filler; S3. The mixture obtained in step S2 above was transferred to a three-roll mill and ground 1-3 times; S4. The mixture obtained by grinding in the above step S3 is transferred from the three-roll grinder to a planetary centrifugal mixer, and stirred for 20-30 minutes under a vacuum environment; finally, low-cost and high-performance thermal conductive silicone grease is obtained.

5. Application of the low-cost, high-performance thermal conductive silicone grease as claimed in any one of claims 1 to 2 in heat dissipation of electronic components.

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