A thermally conductive gel, its preparation method and application
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-05-27
- Publication Date
- 2026-08-14
AI Technical Summary
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[0026]与现有技术相比，该导热凝胶由不含硅材料制备得到，不存在硅油析出、硅氧烷挥发等问题，使用过程不会对电路造成污染、电路短路或接触不良的问题；在常温下具有较好的流变特性，满足点胶工艺要求；在温度敏感性方面，该导热凝胶能够在室温下长期储存，在实际应用中直接通过吸收电子元器件工作产生的热量即可引发交联固化反应，形成柔性固态软垫形态，柔韧性好，有效弥补电子元器件之间的设计公差，且具有缓冲减震作用，具有稳定性、可靠性和使用便捷性等多方面优势。
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Abstract
Description
Technical Field
[0001] This invention relates to the field of thermally conductive interface materials technology, and in particular to a thermally conductive gel, its preparation method, and its application. Background Technology
[0002] With the development of electronic technology, the heat generated by various electronic components has increased significantly. To ensure the stable operation of electronic devices and components, heat dissipation has become an increasingly important issue. Thermal interface materials, as an auxiliary heat dissipation material, can effectively fill the tiny gaps between heat-generating components and heat sinks, improving heat dissipation efficiency, and their applications are becoming increasingly widespread.
[0003] Thermally conductive interface materials are mainly composed of silicone resins as binders, filled with inorganic thermally conductive powders. Among silicone resins, organosiloxanes are the most widely used due to their good molecular flexibility, low viscosity, and ability to hold a large amount of thermally conductive powder. However, in applications involving electronic devices, some electronic devices are sensitive to silicone materials. This necessitates the use of thermally conductive interface materials that do not contain silicon, requiring the development of non-silicone resins as the matrix resin for thermally conductive interface materials.
[0004] Among various thermally conductive interface materials, thermally conductive gels have seen rapid development in recent years due to their compatibility with automated dispensing equipment and high production efficiency. Currently, commercially available non-silicone thermally conductive gels are mainly polyurethane or acrylic systems; however, most of these are two-component thermally conductive gels, requiring the two components to be mixed before extrusion. Polyurethane systems, in particular, are prone to moisture absorption and deterioration. Therefore, it is necessary to design a novel non-silicone one-component thermally conductive gel. Summary of the Invention
[0005] The purpose of this invention is to provide a thermally conductive gel that solves the above-mentioned technical problems and a method for preparing the same.
[0006] Another object of the present invention is to provide an application of the above-mentioned thermally conductive gel as a thermal interface material for electronic devices.
[0007] Therefore, the technical solution of the present invention is as follows:
[0008] A thermally conductive gel comprises, by mass fraction, 3%-10% liquid EPDM rubber, 0.1%-2% peroxide crosslinking agent, 0.1%-1% surface modifier, 0.1%-1% catalyst, and 86%-96.7% thermally conductive powder, with the total mass fraction of all components being 100%. The viscosity of the liquid EPDM rubber is preferably 1000 mPa·s-5000 mPa·s.
[0009] As a more preferred embodiment, the thermally conductive gel is composed of 3.4%-6% liquid EPDM rubber, 0.4% peroxide crosslinking agent, 0.3%-0.4% surface modifier, 0.1% catalyst and 93.2%-95.7% thermally conductive powder by mass fraction, with the total mass fraction of each component being 100%.
[0010] In the above-mentioned thermally conductive gel formulation, liquid EPDM rubber serves as the base resin. By limiting its viscosity, it can achieve synergistic blending with a high proportion of thermally conductive powder, while maintaining good flowability of the prepared thermally conductive gel at room temperature, meeting the requirements of the dispensing process. According to some embodiments of the present invention, when the viscosity of the liquid EPDM rubber exceeds 5000 mPa·s, the proportion of thermally conductive powder mixed in is significantly reduced, resulting in a lower thermal conductivity of the prepared thermally conductive gel.
[0011] In the above thermally conductive gel formulation, the peroxide crosslinking agent is used to decompose under heating conditions to obtain free radicals, thereby initiating crosslinking of unsaturated double bonds in the liquid EPDM rubber molecular chain and forming a three-dimensional network structure to achieve the curing of the thermally conductive gel.
[0012] Specifically, the peroxide crosslinking agent is selected from at least one of α,α-bis(tert-butylperoxy)diisopropylbenzene (BIBP), di-tert-butylperoxide (DTBP), diisopropylbenzene peroxide (DCP), cumene hydroperoxide (CHP), and benzoyl peroxide (BPO).
[0013] In this invention, the amount of peroxide crosslinking agent controls both the curing speed and the degree of crosslinking of the thermal conductive gel, thereby controlling the hardness of the cured thermal conductive gel. Specifically, it is a flexible solid pad that effectively compensates for design tolerances between electronic components and provides cushioning and shock absorption.
[0014] In the above thermally conductive gel formulation, the surface modifier is used to modify the surface of the thermally conductive powder. By coating the surface of the inorganic thermally conductive powder, it improves its compatibility with the organic liquid EPDM rubber, ensuring that the thermally conductive powder can be uniformly dispersed in the liquid EPDM rubber. It also has the effect of reducing the viscosity of the thermally conductive gel, thereby maximizing the filling amount of the thermally conductive powder and preparing a thermally conductive gel with a higher thermal conductivity.
[0015] Specifically, the surface modifier is selected from polyether modifiers or titanate coupling agents. In practical applications, the polyether modifier can specifically be, but is not limited to, Innodis-TX7050 or Solsperse. TM 21000, polyether modifier Solsperse TMOne of 13940; the titanate coupling agent may specifically be the titanate coupling agent TTS.
[0016] In the above thermally conductive gel formulation, the catalyst and the peroxide crosslinking agent are used in combination to control the decomposition of the peroxide crosslinking agent within a specified temperature range (80℃-120℃), thereby promptly initiating the crosslinking reaction of the liquid EPDM rubber. This achieves the purpose of this invention to design a thermally conductive gel that can be stored at room temperature for a long time and directly utilizes the heat generated by electronic components during operation (80℃-120℃) to complete the crosslinking and curing in practical applications.
[0017] Specifically, the catalyst is selected from at least one of acetylacetonate vanadium, N,N'-diethyl-p-toluidine, triethanolamine, and triethylamine.
[0018] According to some embodiments of the present invention, the thermally conductive gel of the present invention will not undergo a curing reaction at 40°C and below, but can undergo a curing reaction at >80°C. This matches the temperature range of 80°C-120°C corresponding to the heat generated when electronic components are working, and also proves its stability when stored at room temperature.
[0019] In the above-mentioned thermally conductive gel formulation, the thermally conductive powder is used to improve the thermal conductivity of the product. By controlling the amount of thermally conductive powder added, thermally conductive gels with different thermal conductivity properties can be prepared. Specifically, the thermally conductive powder can be, but is not limited to, the DRNJ-061 type thermally conductive powder produced by Foshan Jingge in Guangdong.
[0020] A method for preparing the above-mentioned thermally conductive gel, the specific preparation steps of which are as follows:
[0021] S1. Liquid EPDM rubber, peroxide crosslinking agent, surface modifier and catalyst are put into a stirring device and stirred thoroughly under the stirring conditions of 40 rpm to 60 rpm, vacuum degree of -0.08 MPa to -0.1 MPa and stirring time of 20 min to 40 min to prepare liquid base material;
[0022] S2. Add the thermally conductive powder to the liquid base in batches and stir thoroughly. When adding the thermally conductive powder for the first time, set the stirring speed to 8 rpm to 15 rpm, the vacuum degree to -0.08 MPa to -0.1 MPa, and the stirring time to 8 min to 12 min. After each subsequent addition of the thermally conductive powder, set the stirring speed to 25 rpm to 35 rpm, the vacuum degree to -0.08 MPa to -0.1 MPa, and the stirring time to 25 min to 35 min to prepare the thermally conductive gel.
[0023] In practice, a double planetary mixer can be used as the mixing equipment, which ensures that the components are mixed evenly while avoiding the introduction of air into the thermally conductive gel; the thermally conductive powder is preferably added to the liquid base in three steps at a weight ratio of 5:3:2.
[0024] The thermally conductive gel prepared by the method of this invention has good rheological properties at room temperature, and its extrusion rate test result is 23 g / min-35 g / min, which has a high flow rate and meets the requirements of the dispensing process.
[0025] An application of the thermally conductive gel as described above, specifically as a thermal interface material for electronic devices, particularly suitable for use as a thermal interface material for electronic devices sensitive to silicone materials.
[0026] Compared with existing technologies, this thermal conductive gel is made from silicon-free materials, eliminating problems such as silicone oil precipitation and siloxane volatilization. It will not cause circuit contamination, short circuits, or poor contact during use. It exhibits good rheological properties at room temperature, meeting the requirements of the dispensing process. Regarding temperature sensitivity, this thermal conductive gel can be stored at room temperature for extended periods. In practical applications, it directly absorbs the heat generated by electronic components to initiate a cross-linking and curing reaction, forming a flexible solid pad. It has good flexibility, effectively compensating for design tolerances between electronic components, and also provides cushioning and shock absorption. It offers advantages in stability, reliability, and ease of use. Detailed Implementation
[0027] The present invention will be further described below with reference to specific embodiments, but the following embodiments are by no means intended to limit the present invention.
[0028] Example 1
[0029] A thermally conductive gel is prepared using the following method:
[0030] S1. Add 60g of liquid EPDM rubber (3000 mpa·s), 4g of benzoyl peroxide, 1g of acetylacetone vanadium oxide and 3g of polyether modifier Innodis-TX7050 into a double planetary mixer, set the speed to 50 rpm and the vacuum degree to -0.09 mPa, and stir for 30 min to obtain liquid base material.
[0031] S2. Add 932g of thermally conductive powder to the liquid base material in three steps at a weight ratio of 5:3:2 and stir. When adding the thermally conductive powder for the first time, set the stirring speed to 10 rpm, the vacuum degree to -0.09 MPa, and the stirring time to 10 min. After each subsequent addition of the thermally conductive powder, set the stirring speed to 30 rpm, the vacuum degree to -0.09 MPa, and the stirring time to 30 min to prepare the thermally conductive gel.
[0032] Example 2
[0033] A thermally conductive gel is prepared using the following method:
[0034] S1. Add 50g of liquid EPDM rubber (3000 mpa·s), 4g of cumene hydroperoxide, 1g of triethylamine and 4g of titanate coupling agent TTS into a double planetary mixer, set the speed to 50 rpm and the vacuum degree to -0.09 mPa, and stir for 30 min to obtain liquid base material.
[0035] S2. Add 940g of thermally conductive powder to the liquid base material in three steps at a weight ratio of 5:3:2 and stir. When adding the thermally conductive powder for the first time, set the stirring speed to 10 rpm, the vacuum degree to -0.09 MPa, and the stirring time to 10 min. After each subsequent addition of the thermally conductive powder, set the stirring speed to 30 rpm, the vacuum degree to -0.09 MPa, and the stirring time to 30 min to prepare the thermally conductive gel.
[0036] Example 3
[0037] A thermally conductive gel is prepared using the following method:
[0038] S1. Add 34g of liquid EPDM rubber (3000 mpa·s), 4g of benzoyl peroxide, 1g of triethylamine and 4g of titanate coupling agent TTS into a double planetary mixer, set the speed to 50 rpm and the vacuum degree to -0.09 mPa, and stir for 30 min to obtain liquid base material.
[0039] S2. Add 957g of thermally conductive powder to the liquid base material in three steps at a weight ratio of 5:3:2 and stir. When adding the thermally conductive powder for the first time, set the stirring speed to 10 rpm, the vacuum degree to -0.09 MPa, and the stirring time to 10 min. After each subsequent addition of the thermally conductive powder, set the stirring speed to 30 rpm, the vacuum degree to -0.09 MPa, and the stirring time to 30 min to prepare the thermally conductive gel.
[0040] Example 4
[0041] A thermally conductive gel is prepared using the following method:
[0042] S1. Add 30g of liquid EPDM rubber (3000 mpa·s), 1g of α,α-bis(tert-butylperoxy)diisopropylbenzene, 1g of triethanolamine and 1g of polyether modifier Innodis-TX7050 into a double planetary mixer, set the speed to 60 rpm and the vacuum degree to -0.08 mPa, and stir for 40 min to obtain liquid base material;
[0043] S2. Add 967g of thermally conductive powder to the liquid base in three steps at a weight ratio of 5:3:2 and stir. When adding the thermally conductive powder for the first time, set the stirring speed to 15 rpm, the vacuum degree to -0.08 MPa, and the stirring time to 8 min. After each subsequent addition of the thermally conductive powder, set the stirring speed to 35 rpm, the vacuum degree to -0.08 MPa, and the stirring time to 35 min to prepare the thermally conductive gel.
[0044] Example 5
[0045] A thermally conductive gel is prepared using the following method:
[0046] S1. Add 100g of liquid EPDM rubber (3000 mpa·s), 20g of α,α-bis(tert-butylperoxy)diisopropylbenzene, 10g of triethanolamine and 10g of polyether modifier Innodis-TX7050 into a double planetary mixer, set the speed to 40 rpm and the vacuum degree to -0.1 mPa, and stir for 20 min to obtain liquid base material;
[0047] S2. Add 860g of thermally conductive powder to the liquid base in three steps at a weight ratio of 5:3:2 and stir. After the first addition of thermally conductive powder, set the stirring speed to 8 rpm, the vacuum degree to -0.1 MPa, and the stirring time to 12 min. After each subsequent addition of thermally conductive powder, set the stirring speed to 25 rpm, the vacuum degree to -0.1 MPa, and the stirring time to 25 min to prepare the thermally conductive gel.
[0048] Comparative Example 1:
[0049] A thermally conductive gel, the preparation method of which differs from that of Example 1, is as follows: the liquid base material is obtained by adding 61g of liquid EPDM rubber (3000 mpa·s), 4g of benzoyl peroxide and 3g of polyether modifier Innodis-TX7050 into a double planetary mixer and stirring.
[0050] Comparative Example 2
[0051] A thermally conductive gel, the preparation method of which differs from that of Example 1, is that 60g of liquid EPDM rubber (3000 mpa·s) is replaced with 60g of liquid EPDM rubber (3000 mpa·s).
[0052] Comparative Example 3
[0053] A commercially available one-component thermal conductive gel, namely Fill-Gel 450 thermal conductive gel. This thermal conductive gel uses a pre-crosslinking process and will not solidify at either room temperature or high temperature, remaining in a liquid paste state even after prolonged use.
[0054] Comparative Example 4
[0055] A commercially available one-component thermally conductive gel, namely DOWSIL™ TC-3015 Re-workable Thermal Gel. This thermally conductive gel cures at room temperature and cures more rapidly at 60°C and higher temperatures; it is a silicone gel.
[0056] Performance testing:
[0057] The thermally conductive gels prepared in Examples 1-5 and Comparative Examples 1-4 were tested sequentially for extrusion rate, thermal conductivity, curing conditions, and hardness after curing. Specifically, the extrusion rate of the thermally conductive gel was measured by loading the thermally conductive gel into a 30cc EFD tube and applying a constant air pressure of 90psi at room temperature, collecting the weight of all the thermally conductive gel extruded within 1 minute; the thermal conductivity of the thermally conductive gel was obtained based on the ASTM D5470 standard; the curing conditions of the thermally conductive gel were obtained based on curing experiments under different temperature conditions; the hardness of the thermally conductive gel specifically refers to the hardness of the cured thermally conductive gel, which was obtained based on the ASTM D2240 standard. The specific test results are shown in Table 1 below.
[0058] Table 1:
[0059]
[0060] In Table 1, extrusion ratio 1 is the extrusion ratio test result of the newly prepared thermal conductive gel at room temperature, and extrusion ratio 2 is the extrusion ratio test result of the newly prepared thermal conductive gel after being stored at 40℃ for 6 months at room temperature.
[0061] As can be seen from the test results in Table 1, the thermally conductive gels prepared in Examples 1-5 did not solidify after being stored at 40℃ for 6 months and maintained good fluidity. The attenuation rate of the extrusion rate test results did not exceed 12%, proving that they have good stability at room temperature and are easy to transport and store. At the same time, the tests showed that the thermally conductive gels prepared in Examples 1-5 could undergo a curing reaction at 85℃ and 120℃ respectively, forming a soft cushion-like structure with higher reliability. The above curing temperature range is compatible with the temperature environment when electronic components are working, and the curing reaction rate increases with increasing temperature. This confirms that the present invention has successfully prepared a thermally conductive gel that can be stored at room temperature for a long time and can be directly cross-linked and cured by the heat generated by electronic components (80℃-120℃) in practical applications. In addition, the thermal conductivity of the thermally conductive gel can be adjusted in the range of 1.5 W / mK-8.5 W / mK, and the hardness after curing is in the range of 30 Shore 00-72 Shore 00. Considering overall performance, the thermally conductive gels prepared in Examples 1-3 are preferred embodiments of the present invention due to their advantages of good room temperature fluidity, high thermal conductivity, and suitable hardness after curing.
[0062] The thermally conductive gel prepared in Comparative Example 1, lacking a catalyst, exhibits slow curing speed under the operating temperature of electronic components, impacting its long-term reliability as a thermal interface material for electronic components. Comparative Example 2, using liquid EPDM instead of liquid EPDM, failed to crosslink and cure even at high temperatures (150℃ / 2h), remaining a paste after prolonged use. Comparative Example 3, a commercially available thermally conductive gel, while not curing at room temperature, also failed to cure under the operating temperature of electronic components, remaining a paste after extended use. Therefore, Comparative Examples 2 and 3 are similar; both cannot cure into the same cushion-like structure as the thermally conductive gel of this invention, leading to cracking and slippage issues in practical applications, resulting in significantly lower reliability compared to the cushion-like structure. Comparative Example 4, also a commercially available thermally conductive gel, cures under the operating temperature of electronic components, but also cures at room temperature, requiring low-temperature storage and transportation, which is inconvenient for practical application and incurs higher costs.
[0063] In summary, compared with existing commercially available thermal conductive gels, this invention successfully prepares a non-silicone single-component thermal conductive gel that can be stably stored at room temperature and cured at the operating temperature of electronic components. Furthermore, this thermal conductive gel achieves comparable or better performance than commercially available thermal conductive gels in terms of extrusion ratio, thermal conductivity, and hardness after curing. It can serve as an excellent alternative to current thermal interface materials for electronic devices, and is especially suitable for electronic devices that are sensitive to organosilicon materials.
Claims
1. A thermally conductive gel, characterized in that, It is composed of 3%-10% liquid EPDM rubber, 0.1%-2% peroxide crosslinking agent, 0.1%-1% surface modifier, 0.1%-1% catalyst and 86%-96.7% thermally conductive powder by mass fraction, with the total mass fraction of each component being 100%; wherein, the viscosity of the liquid EPDM rubber is 1000mpa·s-5000mpa·s.
2. The thermally conductive gel according to claim 1, characterized in that, The peroxide crosslinking agent is selected from at least one of α,α-bis(tert-butylperoxy)diisopropylbenzene, ditert-butylperoxide, diisopropylbenzene peroxide, cumene hydroperoxide, and benzoyl peroxide.
3. The thermally conductive gel according to claim 1, characterized in that, The surface modifiers selected are polyether modifiers or titanate coupling agents.
4. The thermally conductive gel according to claim 1, characterized in that, The catalyst is selected from at least one of acetylacetonate vanadium, N,N'-diethyl-p-toluidine, triethanolamine, and triethylamine.
5. A method for preparing a thermally conductive gel as described in any one of claims 1-4, characterized in that, The steps are as follows: S1. Liquid EPDM rubber, peroxide crosslinking agent, surface modifier and catalyst are put into a stirring device and stirred thoroughly under the stirring conditions of 40 rpm to 60 rpm, vacuum degree of -0.08 MPa to -0.1 MPa and stirring time of 20 min to 40 min to prepare liquid base material; S2. Add the thermally conductive powder to the liquid base material in batches and continue to stir thoroughly. After the first addition of the thermally conductive powder, set the stirring speed to 8 rpm to 15 rpm, the vacuum degree to -0.08 MPa to -0.1 MPa, and the stirring time to 8 min to 12 min. After each subsequent addition of the thermally conductive powder, set the stirring speed to 25 rpm to 35 rpm, the vacuum degree to -0.08 MPa to -0.1 MPa, and the stirring time to 25 min to 35 min to prepare the thermally conductive gel.
6. An application of a thermally conductive gel as described in any one of claims 1-4, characterized in that, Used as a thermal interface material for electronic devices.