Thermally conductive gel and preparation method and application thereof

Abstract

The application provides a heat-conducting gel and a preparation method and application thereof, characterized in that the heat-conducting filler is a filler modified by a rare earth compound; the filler comprises metal hydroxide and metal oxide; and the mass ratio of the metal hydroxide and the metal oxide is 1:0.8-1. The heat-conducting gel can realize high heat-conducting performance, significantly improve the service life of the material, and has excellent aging stability under a high-temperature environment and other characteristics, can meet the application scene requirement of high heat-conducting and high heat-resistant stability, and effectively improves the heat dissipation efficiency and long-term working reliability of a device.

Description

Technical Field

[0001] This application relates to the field of thermally conductive gel technology, and in particular to a thermally conductive gel, its preparation method, and its application. Background Technology

[0002] Modern electronic devices are evolving towards high integration and high power density. The dense arrangement of heat-generating components significantly increases the pressure on heat dissipation, making efficient heat dissipation crucial for ensuring the lifespan and performance of electronic devices. Thermal interface materials are the core supporting materials for solving these heat dissipation problems, with mainstream products including thermal conductive gel, thermal conductive pads, and thermal conductive grease. Among these, thermal conductive gel is compatible with automated dispensing processes, exhibits excellent adhesion after molding, and can effectively fill heat dissipation gaps. Thanks to its low thermal resistance and good workability, it is widely used in heat dissipation scenarios for precision electronic components.

[0003] Patent CN111961255A discloses a thermally conductive gel using metal hybrid thermally conductive fillers. This solution reduces interfacial thermal resistance through the synergistic effect between the metal fillers, giving the thermally conductive gel a high initial thermal conductivity. However, this solution does not address improvements or optimizations for heat aging resistance. Under high-temperature operating conditions, this thermally conductive gel is prone to problems such as increased hardness, excessive cross-linking, and decreased thermal conductivity. These aging failure phenomena can affect the long-term operational stability and heat dissipation reliability of electronic devices, thereby shortening their service life. Summary of the Invention

[0004] This application is made in view of the above-mentioned problems, and its purpose is to provide a thermally conductive gel with good stability.

[0005] The details are as follows: The first aspect of this application provides a thermally conductive filler, The thermally conductive filler is a filler that has been modified with rare earth compounds; The filler includes metal hydroxides and metal oxides; The mass ratio of the metal hydroxide to the metal oxide is 1:0.8~1.

[0006] The thermally conductive filler according to embodiments of the present invention has at least the following beneficial effects: This application employs rare-earth compound-modified metal oxides. By constructing a uniform rare-earth-based modification layer on the particle surface to shield polar groups, the interfacial compatibility with the organosilicon matrix is ​​significantly improved, effectively reducing interfacial thermal resistance and constructing a highly efficient thermal conduction pathway. Simultaneously, metal hydroxides are introduced, utilizing their high-temperature dehydration endothermic properties and in-situ formation of a dense barrier layer to substantially enhance the material's flame retardancy and heat aging stability. By limiting the mass ratio of metal hydroxides to metal oxides to 1:0.8~1, a balance is achieved between a high thermal conductivity network and a heat-resistant protective structure.

[0007] According to some embodiments of the present invention, the thermally conductive filler comprises the following raw materials in parts by weight: 100 parts of rare earth compound and 180 to 200 parts of filler.

[0008] According to some embodiments of the present invention, the metal oxide is at least one of aluminum oxide, magnesium oxide and zinc oxide.

[0009] According to some embodiments of the present invention, the metal oxide is aluminum oxide.

[0010] According to some embodiments of the present invention, the metal hydroxide is aluminum hydroxide.

[0011] According to some embodiments of the present invention, the rare earth compound is at least one of rare earth oxides and rare earth salts.

[0012] According to some embodiments of the present invention, the rare earth oxide is at least one of La2O3, Nd2O3 and Pr2O3.

[0013] According to some embodiments of the present invention, the rare earth oxide is Nd2O3.

[0014] According to some embodiments of the present invention, the rare earth salt is La(NO3)3.

[0015] According to some embodiments of the present invention, the alumina is at least one of spherical, near-spherical, and angular structures.

[0016] According to some embodiments of the present invention, the alumina has a spherical structure.

[0017] According to some embodiments of the present invention, the magnesium oxide is at least one of spherical, plate-like, and tubular structures.

[0018] According to some embodiments of the present invention, the zinc oxide spherical, gear-shaped, tubular, and spiral screw-shaped structures are at least one of the following.

[0019] According to some embodiments of the present invention, the aluminum hydroxide is at least one of spherical, near-spherical, polyhedral, and plate-like structures.

[0020] According to some embodiments of the present invention, the aluminum hydroxide has a spherical structure.

[0021] According to some embodiments of the present invention, the D50 of the alumina is 5 μm to 50 μm.

[0022] According to some embodiments of the present invention, the D50 of the magnesium oxide is 5 μm to 20 μm.

[0023] According to some embodiments of the present invention, the D50 of the zinc oxide is 10 μm to 30 μm.

[0024] According to some embodiments of the present invention, the D50 of the aluminum hydroxide is 5 μm to 80 μm.

[0025] According to some embodiments of the present invention, the D50 of the rare earth compound is 0.5 μm to 1 μm.

[0026] According to some embodiments of the present invention, the metal hydroxide includes small-particle metal hydroxide and large-particle metal hydroxide.

[0027] According to some embodiments of the present invention, the mass ratio of small-particle metal hydroxide to large-particle metal hydroxide is 1:2.5~3.5.

[0028] According to some embodiments of the present invention, the D50 of the small particulate metal hydroxide is 5 μm to 10 μm.

[0029] According to some embodiments of the present invention, the D50 of the large-particle metal hydroxide is 45 μm to 55 μm.

[0030] A second aspect of this application provides a method for preparing the above-mentioned thermally conductive filler, comprising the following steps: S1: A first mixture is obtained by mixing rare earth compounds and fillers; S2: Roast the first mixture.

[0031] According to some embodiments of the present invention, in the method for preparing the thermally conductive filler, step S1 specifically comprises: S11: After mixing rare earth compounds, fillers and water, heat the mixture to separate the solid and liquid phases and collect the solid phase.

[0032] S12: Wash the solid phase with ammonia water until neutral and then dry it.

[0033] According to some embodiments of the present invention, in step S11, the heating temperature is 45°C to 55°C.

[0034] According to some embodiments of the present invention, in step S11, the heating time is 2.5h to 3.5h.

[0035] According to some embodiments of the present invention, in step S11, the drying temperature is 145°C to 155°C.

[0036] According to some embodiments of the present invention, in step S11, the drying time is 23h~25h.

[0037] According to some embodiments of the present invention, in step S2, the calcination temperature is 1150℃~1250℃.

[0038] According to some embodiments of the present invention, in step S2, the calcination time is 1.5h to 2.5h.

[0039] A third aspect of this application provides a thermally conductive gel, the raw materials of which include the thermally conductive filler described above or the thermally conductive filler prepared by the preparation method described above.

[0040] According to some embodiments of the present invention, the thermally conductive gel comprises component A and component B.

[0041] According to some embodiments of the present invention, component A comprises the following raw materials in parts by weight: 200-300 parts of vinyl silicone oil, 800-1000 parts of thermally conductive filler, 2 parts of coupling agent, and 2-3 parts of catalyst.

[0042] According to some embodiments of the present invention, component B comprises the following raw materials in parts by weight: 90-100 parts of vinyl silicone oil, 50-80 parts of hydrogen-containing silicone oil, 2 parts of coupling agent, 800-1000 parts of thermally conductive filler, 0.6-1 parts of inhibitor, and 2-5 parts of pigment.

[0043] The thermally conductive gel according to embodiments of the present invention has at least the following beneficial effects: This thermally conductive gel contains thermally conductive fillers modified with rare earth compounds, which significantly improves the service life of the material while achieving high thermal conductivity. It also has excellent aging stability under high temperature conditions, which can meet the application requirements of high thermal conductivity and high thermal stability, and effectively improve the heat dissipation efficiency and long-term operational reliability of the device.

[0044] According to some embodiments of the present invention, the number average molecular weight of the vinyl silicone oil in component A is 1000~30000.

[0045] According to some embodiments of the present invention, the number average molecular weight of the vinyl silicone oil in component B is 1000~30000.

[0046] According to some embodiments of the present invention, the viscosity of the vinyl silicone oil in component A is 100 mPa·s to 5000 mPa·s.

[0047] According to some embodiments of the present invention, the viscosity of the vinyl silicone oil in component B is 100 mPa·s to 5000 mPa·s.

[0048] According to some embodiments of the present invention, the vinyl silicone oil in component A is at least one of monovinyl polydimethylsiloxane and polyvinyl polydimethylsiloxane.

[0049] According to some embodiments of the present invention, the vinyl silicone oil in component B is at least one of monovinyl polydimethylsiloxane and polyvinyl polydimethylsiloxane.

[0050] According to some embodiments of the present invention, the hydrogen-containing silicone oil in component B is at least one of end-hydrogen-containing silicone oil and side-hydrogen-containing silicone oil.

[0051] According to some embodiments of the present invention, the hydrogen content of the hydrogen-containing silicone oil is 0.04% to 2%.

[0052] According to some embodiments of the present invention, the hydrogen content of the side-hydrogenated silicone oil is 0.04% to 2%.

[0053] Vinyl silicone oil and hydrogen-containing silicone oil undergo an addition reaction under the action of a catalyst and solidify to form a three-dimensional network gel structure through cross-linking of vinyl groups and silicon-hydrogen bonds. Rare earth oxides, due to their high melting point, can effectively improve the thermal stability, pore structure, and surface activity of the thermally conductive filler; at the same time, the introduction of a high proportion of thermally conductive filler in the system can significantly enhance the thermal conductivity of the gel.

[0054] According to some embodiments of the present invention, the coupling agent in component A is at least one of titanate coupling agents and silane coupling agents.

[0055] According to some embodiments of the present invention, the coupling agent in component B is at least one of titanate coupling agents and silane coupling agents.

[0056] According to some embodiments of the present invention, the catalyst is a platinum-based catalyst.

[0057] According to some embodiments of the present invention, the platinum content in the platinum-based catalyst is 1000ppm to 5000ppm.

[0058] According to some embodiments of the present invention, the inhibitor is at least one of phenylbutynol, methylbutynol, and ethynylcyclohexanol.

[0059] According to some embodiments of the present invention, the pigment is an inorganic pigment.

[0060] A fourth aspect of this application provides a method for preparing the above-mentioned thermally conductive gel, comprising the following steps: Mix the raw materials.

[0061] According to some embodiments of the present invention, the method for preparing the thermally conductive gel includes the following steps: S01: Mix all the raw materials of component A evenly to obtain component A; S02: Mix all the raw materials of component B evenly to obtain component B; S03: Mix component A and component B evenly to obtain the thermally conductive gel.

[0062] According to some embodiments of the present invention, in step S01, the mixing temperature is 55°C to 65°C.

[0063] According to some embodiments of the present invention, in step S01, the mixing time is 1.5h to 2.5h.

[0064] According to some embodiments of the present invention, in step S02, the mixing process is performed under vacuum.

[0065] According to some embodiments of the present invention, in step S02, the vacuum degree of the mixing process is -0.05MPa to -0.15MPa.

[0066] According to some embodiments of the present invention, in step S02, the mixing time is 1.5h to 2.5h.

[0067] According to some embodiments of the present invention, in step S03, the volume ratio of component A to component B is 1:0.5~1.5.

[0068] According to some embodiments of the present invention, in step S03, the mixing temperature is 45°C to 55°C.

[0069] According to some embodiments of the present invention, in step S03, the mixing time is 5.5h to 6.5h.

[0070] According to some embodiments of the present invention, in step S03, the atmosphere of the mixing process is nitrogen.

[0071] The fifth aspect of this application provides an application of the above-mentioned thermally conductive gel in the fields of automobiles and electronic components. Attached Figure Description

[0072] To more clearly illustrate the technical solutions in the embodiments of this drawing or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this drawing. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0073] Figure 1 SEM images of the filler before and after modification with rare earth compound Nd2O3; Figure 2 The images show the XRD patterns of the filler before and after modification with the rare earth compound Nd2O3.

[0074] The purpose, features, and advantages of this accompanying drawing will be further explained in conjunction with the embodiments and with reference to the accompanying drawing. Detailed Implementation

[0075] To make the objectives, technical solutions, and advantages of this application clearer, the following description and illustration are provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application.

[0076] Obviously, the following description is merely some examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios without any inventive effort. Furthermore, it is understood that although the effort involved in such development may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, any changes to design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as insufficient disclosure of the content of this application.

[0077] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0078] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0079] The following are some of the raw materials used in the embodiments of this application: The monovinyl silicone oil used is RH-Vi306B with a viscosity of 300 mPa·s, manufactured by Zhejiang Runhe New Materials Co., Ltd. The double-ended vinyl silicone oil used is RH-Vi311 with a viscosity of 500 mPa·s, manufactured by Zhejiang Runhe New Materials Co., Ltd. The coupling agent used is silane coupling agent KH550; The hydrogen-containing silicone oil used is RH-H518, manufactured by Zhejiang Runhe New Materials Co., Ltd. The hydrogen-containing silicone oil used is RH-DH04, manufactured by Zhejiang Runhe New Materials Co., Ltd. The carbon black used is N330; The platinum catalyst used is YF-T380 with a concentration of 5000 ppm, manufactured by Guangdong Yuanfeng Silicon Materials Co., Ltd. The standard commercial thermal conductive filler used is H-WF-25SP from China Aluminum Shandong Co., Ltd. (brand and manufacturer). Example 1 A thermally conductive filler comprises, by weight, 100 parts of rare earth compound and 180 parts of filler. The rare earth compound is Nd₂O₃ with a particle size of 0.5 μm. The filler consists of aluminum hydroxide and aluminum oxide. Aluminum hydroxide comprises 100 parts, consisting of small particles (D₅₀ = 8 μm) and large particles (D₅₀ = 50 μm) in a mass ratio of 1:3. Aluminum oxide comprises 80 parts, with a D₅₀ of 15 μm. Both aluminum hydroxide and aluminum oxide have a spherical structure.

[0080] The preparation method of this thermally conductive filler includes the following steps: S1: Add aluminum hydroxide, aluminum oxide and Nd2O3 to water, stir at 50°C for 3 hours, filter and wash with ammonia water until the pH value is 6-8 to obtain the first mixture; S2: The first mixture is dried at 150℃ for 24 hours. The dried powder is then pulverized to pass through a 60-mesh sieve, and then calcined at 1200℃ for 2 hours. After natural cooling, the main crystalline phase is α-Al2O3, which also contains NdAlO3 and trace amounts of NdAl. 11 O 18 Composite powder.

[0081] Example 2 A thermally conductive filler, which differs from Example 1 in that: 100 parts of aluminum oxide; The preparation method of this thermally conductive filler is as described in Example 1.

[0082] Example 3 A thermally conductive gel comprising the following raw materials in parts by weight: Component A: 800 parts thermally conductive filler, 200 parts vinyl silicone oil, 2 parts coupling agent, 2 parts catalyst; Component B: 800 parts thermally conductive filler, 100 parts vinyl silicone oil, 70 parts hydrogen-containing silicone oil, 2 parts coupling agent, 0.8 parts inhibitor, 2 parts pigment; Component A consists of 130 parts of monovinyl silicone oil at 300 mPa·s, 70 parts of double-ended vinyl silicone oil at 500 mPa·s, and a platinum catalyst at 5000 ppm. Component B consists of 60 parts of monovinyl silicone oil at 300 mPa·s and 40 parts of double-ended vinyl silicone oil at 500 mPa·s; 20 parts of 0.18% side-ended hydrogen silicone oil and 50 parts of 0.05% end-ended hydrogen silicone oil; the inhibitor is ethynylcyclohexanol; and the pigment is carbon black.

[0083] The thermally conductive fillers used in both component A and component B are the thermally conductive fillers prepared in Example 1.

[0084] The preparation method of this thermally conductive gel includes the following steps: Preparation of S01 and Component A: The vinyl silicone oil and catalyst are stirred and mixed to obtain the first mixture; The thermally conductive filler and coupling agent were stirred and mixed under vacuum conditions of 45°C and -0.1MPa to obtain a second mixture; The second mixture was mixed with the first mixture, stirred at 60°C for 2 hours, and then cooled to obtain component A.

[0085] Preparation of SO2 and component B: A third mixture is prepared by mixing vinyl silicone oil, hydrogen-containing silicone oil, inhibitor, coupling agent and pigment; At 60°C, the thermally conductive filler was added to the third mixture, the vacuum was drawn to -0.1 MPa, and the mixture was stirred for 2 hours to obtain component B.

[0086] S03. Under nitrogen protection, component A and component B are mixed in a volume ratio of 1:1 and stirred at 50°C for 6 hours to obtain a thermally conductive gel. S04. Add 0.5% graphite tablets to the thermally conductive gel, press and shape to obtain the final product.

[0087] Example 4 A thermally conductive gel, which differs from Example 3 in that: (1) The thermally conductive filler in component A is 1000 parts and the vinyl silicone oil is 280 parts; (2) The thermally conductive filler in component B is 1000 parts and the hydrogen-containing silicone oil is 80 parts; (3) The vinyl silicone oil component A consists of 180 parts of monovinyl silicone oil and 100 parts of double-ended vinyl silicone oil; (4) The hydrogen-containing silicone oil of component B has 20 parts of side hydrogen-containing silicone oil and 60 parts of end hydrogen-containing silicone oil.

[0088] The preparation method of this thermally conductive gel is as described in Example 3.

[0089] Example 5 A thermally conductive gel, which differs from Example 3 in that: The thermally conductive fillers in both component A and component B of this thermally conductive gel are the thermally conductive fillers prepared in Example 2. The preparation method of this thermally conductive gel is as described in Example 3.

[0090] Example 6 A thermally conductive gel, which differs from Example 4 in that: The thermally conductive fillers in both component A and component B of this thermally conductive gel are the thermally conductive fillers prepared in Example 2. The preparation method of this thermally conductive gel is as described in Example 4.

[0091] Comparative Example 1 A thermally conductive gel, which differs from Example 3 in that: The thermally conductive filler used in the preparation of this thermally conductive gel is a common commercial thermally conductive filler; The preparation method of this thermally conductive gel is as described in Example 3.

[0092] Test conditions: The adhesive samples of each example group and each comparative group were cured for 7 days under standard conditions (23±2℃, 50±5% RH) and subjected to damp heat aging (85℃, 85% RH) for 7 days. The performance was tested according to the national standard in Table 1. The test results are shown in Table 2.

[0093]

[0094]

[0095] Test results show that the thermally conductive gels obtained in each group of the examples all meet the performance requirements, and the aging performance of each group of the examples is better than that of the control group. This indicates that modifying alumina with rare earth compounds can form a uniform rare earth-based surface modification layer on the surface of alumina particles by combining rare earth ions with hydroxyl groups on the alumina surface. This modification layer can effectively shield the polar groups on the alumina surface, improve the interfacial compatibility between the filler and the organosilicon matrix, reduce interfacial porosity and defects, thereby reducing the interfacial thermal resistance between the filler and the matrix and improving the continuity of the thermal conductivity path. At the same time, the modification layer can regulate the surface polarity of the filler, improve the compatibility between the filler and the organic system, and is beneficial to improving the mechanical stability and long-term reliability of the material.

[0096] Figure 1 The images show SEM images of the filler before and after modification with rare earth compound Nd2O3. Since the rare earth modification mainly affects the metal oxide components in the filler, and metal hydroxides will be converted into metal oxides at high temperatures, the images mainly reflect the optimization effect of the modification process on the surface morphology of the filler's main skeleton (Al2O3). Figure 1In the images, a and b are SEM images before modification, and c and d are SEM images after modification. Before doping with rare earth elements, the alumina is spherical. After doping with rare earth elements, the particles have a regular shape, the average particle size increases, and there is no aggregation or looseness.

[0097] Figure 2 The images show the XRD patterns of the filler before and after modification with the rare earth compound Nd₂O₃. Figure 2 In the diagram, a is the XRD pattern of the undoped rare earth element, and b is the XRD pattern of the modified rare earth element compound. Figure 2 a indicates that undoped alumina only completely transforms from the transition phase to α-Al2O3 at 1200℃; Figure 2 b indicates that the spherical aluminum hydroxide in the system was completely dehydrated at 1200℃, and its crystal form was completely transformed into the thermodynamically stable α-phase alumina. Simultaneously, the original spherical alumina maintained its crystal form and did not undergo phase transformation during sintering. This proves that Nd₂O₃ underwent a complete solid-state reaction with the alumina matrix to form a rare-earth aluminate main phase; a weak NdAl phase can be observed in the spectrum. 11 O 18 Characteristic diffraction peaks ( Figure 2 (As indicated in section a), this indicates that due to an excess of aluminum source, a small amount of aluminum-rich neodymium aluminate secondary phase was formed in the system. Furthermore, only a very weak Nd₂O₃ characteristic peak was present in the sample (…). Figure 2 (As indicated in b), this indicates that the vast majority of neodymium oxide participates in the solid-state reaction, resulting in a high conversion rate, with only trace amounts of rare earth oxides not participating. Overall, the sintered product exhibits a pure phase with few impurities, and the system consists of the main phase α-Al₂O₃, the main modified phase NdAlO₃, and trace amounts of NdAl. 11 O 18 The composition consists of residual Nd₂O₃. Rare earth aluminates are uniformly formed within the alumina matrix without the formation of new impurity phases, demonstrating that the preparation process is mild and controllable, with good phase controllability, successfully producing structurally stable rare earth-modified spherical alumina composite thermally conductive powder. This indicates that rare earth doping effectively promotes the transformation of alumina from the γ / θ phase to the stable α-Al₂O₃, significantly regulating its crystal structure evolution and thermal stability.

[0098] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A thermally conductive filler, characterized in that, The thermally conductive filler is a filler that has been modified with rare earth compounds; The filler includes metal hydroxides and metal oxides; The mass ratio of the metal hydroxide to the metal oxide is 1:0.8~1.

2. The thermally conductive filler as described in claim 1, characterized in that, The thermally conductive filler comprises the following raw materials in parts by weight: 100 parts of rare earth compound and 180 to 200 parts of filler. And / or, the metal oxide is at least one of aluminum oxide, magnesium oxide and zinc oxide; And / or, the metal oxide is aluminum oxide; And / or, the metal hydroxide is aluminum hydroxide; And / or, the rare earth compound is at least one of rare earth oxides and rare earth salts; And / or, the rare earth oxide is at least one of La2O3, Nd2O3 and Pr2O3; And / or, the rare earth oxide is Nd2O3; And / or, the rare earth salt is La(NO3)3.

3. The thermally conductive filler as described in claim 1 or 2, characterized in that, The alumina has at least one of spherical, near-spherical, and angular structures; And / or, the magnesium oxide is at least one of spherical, plate-like and tubular structures; And / or, the zinc oxide is at least one of spherical, gear-shaped, tubular, and spiral screw-shaped structures; And / or, the aluminum hydroxide is at least one of spherical, near-spherical, polyhedral, and plate-like structures; And / or, the D50 of the alumina is 5 μm to 50 μm; And / or, the D50 of the magnesium oxide is 5 μm to 20 μm; And / or, the D50 of the zinc oxide is 10 μm to 30 μm; And / or, the D50 of the aluminum hydroxide is 5 μm to 80 μm; And / or, the D50 of the rare earth compound is 0.5 μm to 1 μm; And / or, the metal hydroxide includes small-particle metal hydroxide and large-particle metal hydroxide; And / or, the mass ratio of small-particle metal hydroxide to large-particle metal hydroxide is 1:2.5~3.5; And / or, the D50 of the small metal hydroxide particles is 5 μm to 10 μm; And / or, the D50 of the large-particle metal hydroxide is 45 μm to 55 μm.

4. A method for preparing the thermally conductive filler as described in any one of claims 1 to 3, characterized in that, S1: A first mixture is obtained by mixing rare earth compounds and fillers; S2: Roast the first mixture.

5. The method for preparing the thermally conductive filler as described in claim 4, characterized in that, In step S2, the calcination temperature is 1150℃~1250℃; And / or, in step S2, the calcination time is 1.5h~2.5h.

6. A thermally conductive gel, characterized in that, The raw materials include the thermally conductive filler as described in any one of claims 1 to 3 or the thermally conductive filler prepared by the preparation method as described in claim 4 or 5.

7. The thermally conductive gel as described in claim 6, characterized in that, The thermally conductive gel comprises component A and component B; And / or, component A comprises the following raw materials in parts by weight: 200-300 parts vinyl silicone oil, 800-1000 parts thermally conductive filler, 2 parts coupling agent and 2-3 parts catalyst; And / or, the B component comprises the following raw materials in parts by weight: 90-100 parts vinyl silicone oil, 50-80 parts hydrogen-containing silicone oil, 2 parts coupling agent, 800-1000 parts thermally conductive filler, 0.6-1 parts inhibitor, and 2-5 parts pigment.

8. The thermally conductive gel as described in claim 6 or 7, characterized in that, The number-average molecular weight of the vinyl silicone oil in component A is 1000~30000; And / or, the number average molecular weight of the vinyl silicone oil in component B is 1000~30000; And / or, the viscosity of the vinyl silicone oil in component A is 100 mPa·s to 5000 mPa·s; And / or, the viscosity of the vinyl silicone oil in component B is 100 mPa·s to 5000 mPa·s; And / or, the vinyl silicone oil in component A is at least one of monovinyl polydimethylsiloxane and polyvinyl polydimethylsiloxane; And / or, the vinyl silicone oil in component B is at least one of monovinyl polydimethylsiloxane and polyvinyl polydimethylsiloxane; And / or, the hydrogen-containing silicone oil in component B is at least one of end-hydrogen-containing silicone oil and side-hydrogen-containing silicone oil; And / or, the hydrogen content of the end-hydrogen-containing silicone oil is 0.04%~2%; And / or, the hydrogen content of the side-containing hydrogen silicone oil is 0.04%~2%; And / or, the coupling agent in component A is at least one of titanate coupling agents and silane coupling agents; And / or, the coupling agent in component B is at least one of titanate coupling agents and silane coupling agents; And / or, the catalyst is a platinum-based catalyst; And / or, the platinum content in the platinum-based catalyst is 1000ppm~5000ppm; And / or, the inhibitor is at least one of phenylbutynol, methylbutynol and ethynylcyclohexanol; And / or, the pigment is an inorganic pigment.

9. A method for preparing the thermally conductive gel according to any one of claims 6 to 8, characterized in that, Includes the following steps: Mix the raw materials.

10. The application of a thermally conductive gel as described in any one of claims 6 to 8 or a thermally conductive gel prepared by the preparation method as described in claim 9, characterized in that, The thermally conductive gel is used in the automotive and electronic component industries.

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