An ultra-low thermal resistance, high-temperature-resistant non-silicon heat-conducting paste and a preparation method thereof

Abstract

The application relates to the technical field of non-silicon heat-conducting paste processing, in particular to a non-silicon heat-conducting paste with ultra-low thermal resistance and high-temperature resistance and a preparation method thereof, which is prepared from the following raw materials in parts by weight: alkyl naphthalene 30-50 parts, alkyl benzene 5-15 parts, hydrogenated terphenyl 10-20 parts, polyether base oil 5-10 parts, superfine heat-conducting filler 60-80 parts, structure directing agent 4-8 parts, perfluoropolyether phosphate 0.5-1 part and antioxidant 1-3 parts. By adopting the above formula, a non-silicon compound oil phase system is constructed, the superfine heat-conducting filler, the structure directing agent and the perfluoropolyether phosphate are combined, high thermal conductivity, ultra-low thermal resistance and excellent interface adhesion are realized, the risk of silicon volatilization pollution is completely eliminated, high-temperature oxidation resistance and long-term reliability are improved, and the urgent needs of 5G, AI and other high-heat-density electronic equipment for non-silicon high-performance thermal interface materials are effectively met.

Description

Technical Field

[0001] This application relates to the field of non-silicone thermal paste processing technology, and more specifically, to a non-silicone thermal paste with ultra-low thermal resistance and high temperature resistance and its preparation method. Background Technology

[0002] With the rapid development of 5G communication and artificial intelligence technologies, the heat flux density of electronic devices continues to rise, placing higher demands on heat dissipation systems. Thermal interface materials, as the key medium connecting heat-generating components and heat sinks, directly determine the reliability of the equipment.

[0003] Currently, the mainstream commercially available products are silicone-containing thermal conductive pastes, which use polydimethylsiloxane as a base oil and are formulated with high thermal conductivity fillers such as alumina, boron nitride, and silver powder. These materials have technical advantages such as high intrinsic thermal conductivity, excellent interfacial wettability, and strong application adaptability, and are widely used in consumer electronics and traditional industrial fields. However, the inherent volatility of siloxane systems limits their use. Under long-term service conditions at 85°C, low molecular weight siloxanes are prone to migration and volatilization. The volatilized siloxane components condense on precision optical surfaces, forming an irreversible contamination film, leading to decreased optical transmittance and enhanced laser scattering. Simultaneously, volatilized siloxane molecules deposit on circuit board surfaces, adsorbing ambient moisture and forming conductive pathways, causing contact impedance drift, signal transmission distortion, and even short-circuit failure. Especially in optically sensitive electronic devices such as lidar, endoscopes, and CT detectors, as well as implantable medical devices with extremely high reliability requirements, the use of silicone-containing TIMs is strictly limited or completely prohibited.

[0004] Despite industry attempts to improve the situation by increasing the molecular weight of silicone oil and adding volatilization inhibitors, the volatilization problem of siloxanes is essentially an inherent characteristic of the materials and is difficult to eliminate fundamentally. Existing silicone-free alternatives mostly use hydrocarbon or synthetic ester base oils, which avoid the risk of silicone contamination, but generally suffer from low thermal conductivity, poor high-temperature oxidation resistance, and insufficient compatibility with metal interfaces, making it difficult to meet the heat dissipation requirements of high-power devices. Therefore, achieving a silicone-free solution while simultaneously possessing high thermal conductivity, low thermal resistance, and long-term reliability has become a bottleneck restricting the development of thermal management technologies for next-generation electronic devices. Summary of the Invention

[0005] To address the issue that non-silicone thermal pastes cannot simultaneously achieve high thermal conductivity, low thermal resistance, and long-term reliability, this application provides a non-silicone thermal paste with ultra-low thermal resistance and high temperature resistance, as well as its preparation method.

[0006] In the first aspect, this application provides a non-silicone thermal paste with ultra-low thermal resistance and high temperature resistance, using the following technical solution: A non-silicone thermal grease with ultra-low thermal resistance and high temperature resistance is prepared from the following raw materials in parts by weight: 30-50 parts of alkylnaphthalene 5-15 parts of alkylbenzene 10-20 parts of hydrogenated terphenyl 5-10 parts of polyether base oil 60-80 parts of ultrafine thermally conductive filler 4-8 parts of structure guiding agent 0.5-1 part of perfluoropolyether phosphate Antioxidant 1-3 parts.

[0007] By adopting the above technical solution, alkylnaphthalene and hydrogenated terphenyl ensure the basic high-temperature resistance performance, alkylbenzene regulates the viscosity of the system, and polyether improves the wetting and dispersibility of the ultrafine thermally conductive filler. The four work synergistically to provide a stable medium for the uniform distribution of the filler. The ultrafine thermally conductive filler, as a thermally conductive functional filler, works synergistically with the compound oil to form a continuous thermal conduction path. Combined with the steric hindrance regulation effect of the structure-directing agent, the filler packing density is optimized and agglomeration is reduced, greatly reducing the contact thermal resistance between fillers and the interfacial thermal resistance of the paste. Perfluoropolyether phosphate, on the one hand, works synergistically with the compound oil to enhance the lubricity of the paste, and on the other hand, forms chemical bonds with the metal interface through polar groups. It also assists in the directional dispersion of the filler in the interfacial region. Together with the structure-directing agent, it improves the compatibility and adhesion between the paste and the metal interface, reducing the risk of peeling between the paste and the interface during high-temperature service. This solves the problems of poor high-temperature oxidation resistance and insufficient compatibility with the metal interface in existing silicone-free thermally conductive pastes, ensuring the stable performance of the paste under long-term high-temperature conditions, without delamination, oil seepage, or other failure phenomena. Furthermore, the use of high-temperature resistant and low-volatility components such as alkylnaphthalene and hydrogenated terphenyl in this application, along with added antioxidants, can effectively enhance the antioxidant properties of the paste under high-temperature conditions and delay the aging and degradation of the oil phase.

[0008] Simultaneously, these four components constitute a silicone-free oil-phase system, completely eliminating the polydimethylsiloxane component. This fundamentally solves the problem of low-molecular-weight siloxane migration, volatilization, and condensation on precision optical surfaces to form a contaminating film when traditional silicone-containing thermal pastes are used for long-term operation at temperatures of 85°C and above. Furthermore, by combining ultrafine thermally conductive fillers and structure-directing agents, the dispersion and packing structure of the fillers in the oil-phase system can be optimized, reducing the contact thermal resistance between fillers and the interfacial thermal resistance between the paste and the heating element / heat sink. Compared to existing silicone-free thermal pastes based on hydrocarbons and synthetic esters, the thermal conductivity of this paste is significantly improved, enabling efficient heat transfer from high-power electronic devices and meeting the heat dissipation requirements of high heat flux density scenarios such as 5G communication and artificial intelligence equipment.

[0009] Preferably, the structure directing agent is composed of 4-cyanobiphenyl and 1-ethyl-3-methylimidazolium hexafluorophosphate in a weight ratio of 1:(1-3).

[0010] By employing the above technical solutions, 4-cyanobiphenyl can induce the orderly arrangement of ultrafine thermally conductive fillers along the heat flow direction under the action of a thermal field, constructing a low-resistance thermally conductive pathway. Meanwhile, 1-ethyl-3-methylimidazolium hexafluorophosphate not only stabilizes the filler dispersion and prevents sedimentation and agglomeration through electrostatic interaction, but its fluorinated anions can also synergistically enhance the filler / matrix interface compatibility with perfluoropolyether phosphate, reducing interfacial phonon scattering. The synergistic effect of these two components improves the continuity and density of the thermally conductive network, maintaining the uniformity and stability of the paste even under high filler loads, thereby achieving ultra-low thermal resistance and long-term thermal cycling reliability. Preferably, the alkylnaphthalene has a carbon number of C. 10 -C 14 Monoalkyl naphthalene or dialkyl naphthalene.

[0011] By adopting the above technical solution, its molecular structure combines the high thermal stability of aromatic rings with the low volatility and good lubricity of moderately long alkyl chains. 10 -C 14 The alkyl substitution effectively suppresses the volatility of small molecule naphthalene compounds, improving the long-term service stability of the thermal paste in high-temperature environments above 85°C. At the same time, the carbon chain length ensures low viscosity and good wettability of the base oil while avoiding crystallization or low-temperature fluidity degradation caused by excessively long alkyl chains. This helps the thermal paste maintain excellent interfacial filling ability over a wide temperature range, thereby synergistically achieving high thermal conductivity and reliable thermal contact.

[0012] Preferably, the alkylbenzene has a carbon number of C. 12 -C 16 Straight-chain alkylbenzenes with a benzene ring substitution degree of 1-1.5.

[0013] By adopting the above technical solution, the viscosity and flowability of the thermal paste system can be effectively controlled while ensuring good thermal stability: the carbon chain length is moderate, which avoids the problems of high-temperature volatility and insufficient lubricity of short-chain alkylbenzenes, and overcomes the defects of excessively high viscosity and poor workability of long-chain alkylbenzenes at low temperatures; the moderately substituted benzene ring structure helps to maintain the balance between molecular rigidity and polarity, improves its compatibility with main oil phase components such as alkylnaphthalene and hydrogenated terphenyl, and works synergistically with polyether base oil to improve the wetting and dispersion ability of ultrafine thermally conductive fillers, thereby achieving excellent rheological properties, thermal conductivity and long-term service stability of the paste in a wide temperature range without introducing silicon elements.

[0014] Preferably, the degree of hydrogenation of the hydrogenated terphenyl is 70%-95%, its aromatic content is less than 5 wt%, and the flash point of the hydrogenated terphenyl is greater than 200°C.

[0015] By adopting the above technical solutions, the high-temperature resistance and thermal oxidation stability of the thermal conductive paste are further improved: the high degree of hydrogenation effectively saturates the unsaturated bonds in the terphenyl molecule, significantly reducing its reactivity and volatility at high temperatures. Its interaction with the thermally conductive filler promotes the construction of a thermally conductive network, improving thermal conductivity. The extremely low aromatic content avoids the risk of carbon deposition caused by aromatic ring cracking or coking at high temperatures, ensuring cleanliness during long-term service; while the high flash point endows the system with excellent high-temperature safety and operational stability. Together with alkyl naphthalene and other components, it constructs a silicone-free oil-based matrix with low volatility, high thermal stability, and good rheological properties, providing key support for achieving ultra-low thermal resistance and long-term reliability.

[0016] Preferably, the polyether base oil is a propylene oxide homopolymer or a propylene oxide-ethylene oxide copolymer with a number-average molecular weight of 500-2000 and a hydroxyl value of less than 5 mg KOH / g.

[0017] By adopting the above technical solution, the wetting and dispersion capabilities of ultrafine thermally conductive fillers are significantly improved while ensuring excellent thermal stability. A suitable molecular weight range ensures that the polyether has good flowability and compatibility, avoiding excessively high viscosity due to excessively large molecules or evaporation loss due to excessively small molecules. The low hydroxyl value indicates extremely low terminal hydroxyl content, effectively suppressing oil phase aging, gelation, or oil seepage caused by hydroxyl oxidation or cross-linking at high temperatures. Simultaneously, the ether bonds in the polyether segments have strong polarity, enabling effective interaction with the filler surface, promoting uniform dispersion and stable suspension of the filler in the silicone-free oil phase, reducing agglomeration and sedimentation, thereby optimizing the continuity of the thermal conductivity pathway, reducing interfacial thermal resistance, and synergistically achieving high thermal conductivity, low thermal resistance, and long-term high-temperature service stability with other components.

[0018] Preferably, the ultrafine thermally conductive filler is composed of boron nitride nanosheets, spherical alumina and aluminum nitride whiskers in a weight ratio of (5-7):(1-1.5):0.5.

[0019] By employing the above technical solutions, a highly efficient thermally conductive network with multi-scale and multi-morphology synergy can be constructed. High aspect ratio boron nitride nanosheets provide excellent in-plane thermal conductivity pathways and enhance interfacial adhesion; spherical alumina serves as a filler framework, effectively reducing system viscosity, increasing packing density, and improving process flowability; while a small amount of aluminum nitride whiskers bridges the two-dimensional nanosheets and spherical particles through their one-dimensional fibrous structure, inhibiting filler agglomeration and forming through-hole thermally conductive channels, thus reducing the contact thermal resistance between fillers. The synergy of these three components not only fully leverages the high thermal conductivity of each material, achieving a dense, continuous, and low interfacial impedance thermal conduction path in a silicone-free phase, but also significantly improves the overall thermal conductivity and thermal response efficiency of the thermal paste, meeting the stringent requirements of high-power electronic devices for ultra-low thermal resistance and long-term reliable heat dissipation.

[0020] Preferably, the boron nitride nanosheets have a radial dimension of 200-500 nm and a thickness of 5-15 nm, the spherical alumina has an average particle size of 50-100 nm, and the aluminum nitride whiskers have a diameter of 30-50 nm.

[0021] By employing the above technical solution, efficient synergy and dense packing of multi-scale fillers in a silicone-free phase can be achieved: nanoscale spherical alumina fills the spaces between large-sized boron nitride nanosheets, effectively reducing voids and increasing overall packing density; ultrathin boron nitride nanosheets, with their high specific surface area and two-dimensional structure, form a continuous thermally conductive plane at the interface, enhancing in-plane thermal diffusion; while fine-diameter alumina whiskers are interspersed in the gaps between the sheets and spheres, opening up vertical heat conduction paths through one-dimensional bridging and suppressing interfacial phonon scattering. The combined use of these three components not only avoids the problems of paste roughness, pumping effect, and poor interfacial contact caused by micron-sized fillers, but also reduces the contact thermal resistance between fillers and between fillers and the matrix. While ensuring good workability and interfacial wettability, a three-dimensional, interconnected, low-thermal-resistance, and high-thermal-conductivity composite network structure is constructed, thereby comprehensively improving the thermal management performance and long-term service reliability of the thermal paste.

[0022] Preferably, the antioxidant is composed of alkylated diphenylamine and triphenyl phosphite in a weight ratio of 1:(3-5).

[0023] By employing the above technical solution, alkylated diphenylamine acts as the primary antioxidant, effectively quenching alkyl and alkoxy radicals generated in the oil phase at high temperatures by providing hydrogen atoms, thus inhibiting chain oxidation reactions. Triphenyl phosphite acts as an auxiliary antioxidant, efficiently decomposing hydroperoxides generated during thermal oxidation and blocking their further decomposition into free radicals. It also has a metal passivation effect, reducing the risk of catalytic oxidation at metal interfaces. The two components, in a specific ratio, produce a synergistic effect, significantly delaying the aging, discoloration, and viscosity degradation of high-temperature base oils such as alkylnaphthalenes and hydrogenated terphenyls during long-term high-temperature service. Furthermore, it effectively prevents oil seepage, hardening, or thermal conductivity degradation caused by oil phase degradation, thereby ensuring the long-term thermal stability and reliability of non-silicone thermal paste in high heat flux density applications.

[0024] Secondly, this application provides a method for preparing an ultra-low thermal resistance, high-temperature resistant non-silicone thermal grease, using the following technical solution: A method for preparing an ultra-low thermal resistance, high-temperature resistant non-silicone thermal grease includes the following preparation steps: Ultrafine thermally conductive filler is dispersed in alkylnaphthalene, heated to 120-140℃ and stirred, then cooled to 80-100℃. Alkylbenzene, hydrogenated terphenyl, polyether base oil, structure directing agent, perfluoropolyether phosphate ester and antioxidant are added sequentially. The mixture is then processed by a microfluidic homogenizer under a vacuum of less than 100Pa and a homogenization pressure of 100-150MPa. After vacuum degassing at 60-80℃ and curing for 3-4 hours, a non-silicone thermally conductive paste is obtained.

[0025] By adopting the above technical solution, the high dispersion and stable composite of ultrafine thermally conductive fillers in a silicone-free phase are effectively achieved. First, the ultrafine thermally conductive fillers are pre-dispersed in high-boiling-point alkyl naphthalene and activated and stirred at 120-140℃, which helps remove adsorbed water and weakly bound impurities from the filler surface and promotes the initial wetting of the filler by the alkyl naphthalene. Then, the temperature is lowered to 80-100℃, and low-viscosity components such as alkylbenzene and hydrogenated terphenyl, as well as functional additives, are introduced sequentially to avoid thermal degradation of polyethers or antioxidants at high temperatures and to ensure the chemical stability of each component. High-pressure micro-jet homogenization is then performed under vacuum and high pressure conditions, utilizing cavitation, shearing, and impact effects to strongly break up filler agglomeration. The process involves creating a composite oil phase that allows boron nitride nanosheets, spherical alumina, and aluminum nitride whiskers to achieve a nanoscale uniform distribution and form a dense thermally conductive network. Finally, the mixture is vacuum degassed and cured at 60-80℃. This process thoroughly eliminates any air bubbles to reduce interfacial thermal resistance and promotes the full interaction between the perfluoropolyether phosphate ester and the metal interface mimicry, while optimizing the spatial arrangement of the structure-directing agent. This results in a non-silicone thermal paste that is structurally stable, free from delamination and oil seepage, has ultra-low thermal resistance, and is resistant to high temperatures. This significantly improves its thermal conductivity and long-term reliability in high-power electronic devices.

[0026] In summary, this application has the following beneficial effects: 1. This invention provides an ultra-low thermal resistance, high-temperature resistant non-silicone thermal grease. By employing a compound of alkylnaphthalene, alkylbenzene, hydrogenated terphenyl, and polyether base oil to construct a silicone-free oil phase system, it completely avoids the optical contamination and circuit failure risks caused by the volatilization of siloxanes at high temperatures in traditional silicone-containing thermal greases. The formulation introduces a multi-scale ultrafine thermally conductive filler composed of boron nitride nanosheets, spherical alumina, and aluminum nitride whiskers, combined with a structure-directing agent and perfluoropolyether phosphate, effectively optimizing filler dispersion and packing density, reducing contact and interfacial thermal resistance. The perfluoropolyether phosphate can also form chemical bonds with the metal interface, improving adhesion and long-term stability. Combined with a specific ratio of composite antioxidants, it significantly enhances high-temperature oxidation resistance. The overall solution achieves silicone-free operation while possessing high thermal conductivity, low thermal resistance, excellent interfacial compatibility, and long-term high-temperature service reliability, meeting the stringent heat dissipation requirements of high heat flux density electronic devices such as 5G and AI. Detailed Implementation Example Example 1

[0027] A non-silicone thermal grease with ultra-low thermal resistance and high temperature resistance is prepared by the following method: 600g of ultrafine thermally conductive filler was dispersed in 300g of alkylnaphthalene, heated to 120℃ and stirred, then cooled to 80℃. 50g of alkylbenzene, 100g of hydrogenated terphenyl, 50g of polyether base oil, 40g of structure directing agent, 5g of perfluoropolyether phosphate ester and 10g of antioxidant were added sequentially and stirred. The mixture was then processed by a microfluidic homogenizer under a vacuum of 100Pa and a homogenization pressure of 100MPa. After vacuum degassing at 60℃ and curing for 3 hours, a non-silicone thermally conductive paste was obtained.

[0028] The structure-directing agent is composed of 4-cyanobiphenyl and 1-ethyl-3-methylimidazolium hexafluorophosphate in a weight ratio of 1:1; Alkylnaphthalene is a carbon group with 12 carbon atoms. 10 Monoalkyl naphthalene; Alkylbenzene is a carbon group with 12 carbon atoms. 12 A straight-chain alkylbenzene with a benzene ring substitution degree of 1; The degree of hydrogenation of hydrogenated terphenyl is 70%, its aromatic content is 4 wt%, and the flash point of hydrogenated terphenyl is greater than 200℃. The polyether base oil is a propylene oxide homopolymer with a number-average molecular weight of 500 and a hydroxyl value of 5 mgKOH / g. The ultrafine thermally conductive filler is composed of boron nitride nanosheets, spherical alumina and aluminum nitride whiskers in a weight ratio of 5:1:0.5. The radial dimension of the boron nitride nanosheets is 200 nm and the thickness is 5 nm, the average particle size of the spherical alumina is 50 nm, and the aluminum nitride whiskers are 30 nm. The perfluoropolyether phosphate has a phosphorus content of 1.8 wt% and a fluorine content of 55 wt%, and the number average molecular weight of the perfluoropolyether phosphate is 1500 g / mol. The antioxidant is composed of alkylated diphenylamine and triphenyl phosphite in a weight ratio of 1:3. Example 2

[0029] A non-silicone thermal grease with ultra-low thermal resistance and high temperature resistance is prepared by the following method: 700g of ultrafine thermally conductive filler was dispersed in 400g of alkylnaphthalene, heated to 130℃ and stirred, then cooled to 90℃. 100g of alkylbenzene, 150g of hydrogenated terphenyl, 80g of polyether base oil, 60g of structure directing agent, 8g of perfluoropolyether phosphate, and 20g of antioxidant were added sequentially and stirred. The mixture was then processed by a microfluidic homogenizer under a vacuum of 90Pa and a homogenization pressure of 120MPa. After vacuum degassing at 70℃ and curing for 3.5 hours, a non-silicone thermally conductive paste was obtained.

[0030] The structure-directing agent is composed of 4-cyanobiphenyl and 1-ethyl-3-methylimidazolium hexafluorophosphate in a weight ratio of 1:2; Alkylnaphthalene is a carbon group with 12 carbon atoms. 12 Monoalkyl naphthalene; Alkylbenzene is a carbon group with 12 carbon atoms. 14 A straight-chain alkylbenzene with a benzene ring substitution degree of 1.2; The degree of hydrogenation of hydrogenated terphenyl is 85%, its aromatic content is 3 wt%, and the flash point of hydrogenated terphenyl is greater than 200℃. The polyether base oil is a propylene oxide homopolymer with a number-average molecular weight of 1000 and a hydroxyl value of 3 mgKOH / g. The ultrafine thermally conductive filler is composed of boron nitride nanosheets, spherical alumina and aluminum nitride whiskers in a weight ratio of 6:1.2:0.5. The radial dimension of the boron nitride nanosheets is 300 nm and the thickness is 10 nm, the average particle size of the spherical alumina is 80 nm, and the aluminum nitride whiskers are 40 nm. The perfluoropolyether phosphate has a phosphorus content of 1.8 wt% and a fluorine content of 55 wt%, and the number average molecular weight of the perfluoropolyether phosphate is 1500 g / mol. The antioxidant is composed of alkylated diphenylamine and triphenyl phosphite in a weight ratio of 1:4. Example 3

[0031] A non-silicone thermal grease with ultra-low thermal resistance and high temperature resistance is prepared by the following method: 800g of ultrafine thermally conductive filler was dispersed in 500g of alkylnaphthalene, heated to 140℃ and stirred, then cooled to 100℃. 150g of alkylbenzene, 200g of hydrogenated terphenyl, 100g of polyether base oil, 80g of structure-directing agent, 10g of perfluoropolyether phosphate, and 30g of antioxidant were added sequentially and stirred. The mixture was then processed by a microfluidic homogenizer under a vacuum of 90Pa and a homogenization pressure of 150MPa. After vacuum degassing at 80℃ and curing for 4 hours, a non-silicone thermally conductive paste was obtained.

[0032] The structure-directing agent is composed of 4-cyanobiphenyl and 1-ethyl-3-methylimidazolium hexafluorophosphate in a weight ratio of 1:3; Alkyl naphthalene is dialkyl naphthalene; Alkylbenzene is a carbon group with 12 carbon atoms. 16 A straight-chain alkylbenzene with a benzene ring substitution degree of 1.5; The degree of hydrogenation of hydrogenated terphenyl is 95%, its aromatic content is 2wt%, and the flash point of hydrogenated terphenyl is greater than 200℃. The polyether base oil is a propylene oxide-ethylene oxide copolymer with a number-average molecular weight of 2000 and a hydroxyl value of 3 mgKOH / g. The ultrafine thermally conductive filler is composed of boron nitride nanosheets, spherical alumina and aluminum nitride whiskers in a weight ratio of 7:1.5:0.5. The radial dimension of boron nitride nanosheets is 500 nm and the thickness is 15 nm; the average particle size of spherical alumina is 100 nm; and the alumina whiskers are 30-50 nm. The perfluoropolyether phosphate has a phosphorus content of 1.8 wt% and a fluorine content of 55 wt%, and the number average molecular weight of the perfluoropolyether phosphate is 1500 g / mol. The antioxidant is composed of alkylated diphenylamine and triphenyl phosphite in a weight ratio of 1:5. Example 4

[0033] A non-silicone thermal grease with ultra-low thermal resistance and high temperature resistance. The difference between this embodiment and Embodiment 1 is that the structure guiding agent is 4-cyanobiphenyl. Example 5

[0034] A non-silicone thermal grease with ultra-low thermal resistance and high temperature resistance is described in this embodiment, which differs from Embodiment 1 in that caprolactam is used instead of 4-cyanobiphenyl. Example 6

[0035] A non-silicone thermal grease with ultra-low thermal resistance and high temperature resistance is described in this embodiment, which differs from Embodiment 1 in that the ultrafine thermally conductive filler is composed of boron nitride nanosheets, spherical alumina and aluminum nitride whiskers in a weight ratio of 1:1:0.5. Example 7

[0036] A non-silicone thermal paste with ultra-low thermal resistance and high temperature resistance. The difference between this embodiment and Embodiment 1 is that the average particle size of the spherical alumina is 200 nm. Example 8

[0037] A non-silicone thermal grease with ultra-low thermal resistance and high temperature resistance is described in this embodiment, which differs from Embodiment 1 in that the ultra-fine thermally conductive filler is boron nitride nanosheets. Example 9

[0038] A non-silicone thermal grease with ultra-low thermal resistance and high temperature resistance is described in this embodiment, which differs from Embodiment 1 in that the ultrafine thermally conductive filler is composed of boron nitride nanosheets and spherical alumina in a weight ratio of 5:1. Comparative Example

[0039] Comparative Example 1 A non-silicone thermal paste, the difference between this comparative example and Example 1 is that mineral oil is used instead of hydrogenated terphenyl.

[0040] Comparative Example 2 A non-silicone thermal paste, which differs from Example 1 in that it does not contain perfluoropolyether phosphate.

[0041] Comparative Example 3 A non-silicone thermal paste, the difference between this comparative example and Example 1 is that 1,4-cyclohexanedicarboxylate diisooctyl ester is used instead of polyether base oil.

[0042] Comparative Example 4 A non-silicone thermal paste, which differs from Example 1 in that no structure-directing agent is added. Test methods / detection methods

[0043] Thermal conductivity and thermal resistance were tested according to ASTM D5470. Optical surface contamination; The non-silicone thermal pastes prepared in Examples 1-9 and Comparative Examples 1-4 were sandwiched between quartz glass sheets (simulating the interface of optical components), and the visible light transmittance of the quartz glass was tested. After aging at 85°C for 1000 hours, the visible light transmittance of the quartz glass was tested again, and the decrease in transmittance was calculated. Interfacial adhesion test: Following ASTM D1002-2010, "Standard Test Method for Single Lap Joint Shear Strength," aluminum / copper was used as the substrate. The sample was coated and cured to form an lap joint (lap area 25 mm × 10 mm). Shear strength was tested at room temperature and after 1000 hours of aging with double 85 nitrate. Experimental data are shown in Table 1. Table 1. Experimental data of Examples 1-8 and Comparative Examples 1-4

[0044] As can be seen from the test data in the table, the non-silicone thermal paste prepared by the formulation in this application has good thermal conductivity, high temperature resistance and adhesion, while maintaining low thermal resistance.

[0045] Compared with Comparative Examples 1-4, Example 1 showed that the thermal conductivity and interfacial adhesion of Comparative Examples 1-4 were reduced, while the decrease in thermal resistance and transmittance was increased. The shear strength after aging with double 85 was significantly reduced. This indicates that in this application, hydrogenated terphenyl plays an irreplaceable role in ensuring the high-temperature resistance and system stability of the oil phase, perfluoropolyether phosphate plays an irreplaceable role in improving interfacial compatibility and the continuity of the thermal conductivity pathway, polyether base oil plays an irreplaceable role in optimizing the wetting and dispersibility of the filler, and structure-directing agent plays an irreplaceable role in constructing an efficient thermal conductivity network and inhibiting filler agglomeration.

[0046] Comparing Examples 1 with Examples 4-5, it can be seen that the binary compound structure-directing agent composed of 4-cyanobiphenyl and 1-ethyl-3-methylimidazolium hexafluorophosphate, through the directional arrangement of aromatic small molecules and the electrostatic stabilization and interfacial compatibility synergistic effect of ionic liquids, is superior to the single 4-cyanobiphenyl or caprolactam substitution system in optimizing the dispersion state of multi-scale ultrafine thermally conductive fillers, constructing a continuous and efficient thermally conductive network, improving the bonding force between the paste and the metal interface, and enhancing the anti-fouling ability. This indicates that the specific compound composition of the structure-directing agent in this application is an important factor in ensuring that the non-silicone thermally conductive paste has both high thermal conductivity, ultra-low thermal resistance, and excellent interfacial reliability.

[0047] Comparing Examples 1 with Examples 6-8, it is evident that the multi-scale, multi-morphology synergistic ultrafine thermal conductive filler system in this application, composed of boron nitride nanosheets, spherical alumina, and aluminum nitride whiskers in a specific ratio, can construct a continuous and dense thermal conductive network through the complementary stacking and bridging effect of sheets-spheres-whiskers. This effectively inhibits filler agglomeration, reduces contact thermal resistance and interfacial thermal resistance, and simultaneously enhances the bonding force between the paste and the metal interface and its anti-fouling ability. As a result, the non-silicone thermal conductive paste possesses the comprehensive advantages of high thermal conductivity, ultra-low thermal resistance, and excellent long-term reliability.

[0048] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A non-silicone thermal grease with ultra-low thermal resistance and high temperature resistance, characterized in that, It is prepared from the following raw materials in parts by weight: 30-50 parts of alkylnaphthalene 5-15 parts of alkylbenzene 10-20 parts of hydrogenated terphenyl 5-10 parts of polyether base oil 60-80 parts of ultrafine thermally conductive filler 4-8 parts of structure guiding agent 0.5-1 part of perfluoropolyether phosphate Antioxidant 1-3 parts.

2. The ultra-low thermal resistance, high-temperature resistant non-silicone thermal grease according to claim 1, characterized in that: The structure-directing agent is composed of 4-cyanobiphenyl and 1-ethyl-3-methylimidazolium hexafluorophosphate in a weight ratio of 1:(1-3).

3. The ultra-low thermal resistance, high-temperature resistant non-silicone thermal grease according to claim 1, characterized in that: The alkylnaphthalene has a carbon number of C. 10 -C 14 Monoalkyl naphthalene or dialkyl naphthalene.

4. The ultra-low thermal resistance, high-temperature resistant non-silicone thermal grease according to claim 1, characterized in that: The alkylbenzene has a carbon number of C. 12 -C 16 Straight-chain alkylbenzenes with a benzene ring substitution degree of 1-1.

5.

5. The ultra-low thermal resistance, high-temperature resistant non-silicone thermal grease according to claim 1, characterized in that: The hydrogenation degree of the hydrogenated terphenyl is 70%-95%, its aromatic content is less than 5 wt%, and the flash point of the hydrogenated terphenyl is greater than 200℃.

6. The ultra-low thermal resistance, high-temperature resistant non-silicone thermal grease according to claim 1, characterized in that: The polyether base oil is a propylene oxide homopolymer or a propylene oxide-ethylene oxide copolymer with a number average molecular weight of 500-2000 and a hydroxyl value of less than 5 mg KOH / g.

7. The ultra-low thermal resistance, high-temperature resistant non-silicone thermal grease according to claim 1, characterized in that: The ultrafine thermally conductive filler is composed of boron nitride nanosheets, spherical alumina and aluminum nitride whiskers in a weight ratio of (5-7):(1-1.5):0.

5.

8. The ultra-low thermal resistance, high-temperature resistant non-silicone thermal grease according to claim 1, characterized in that: The boron nitride nanosheets have a radial dimension of 200-500 nm and a thickness of 5-15 nm, the spherical alumina has an average particle size of 50-100 nm, and the aluminum nitride whiskers have a diameter of 30-50 nm.

9. The ultra-low thermal resistance, high-temperature resistant non-silicone thermal grease according to claim 1, characterized in that: The antioxidant is composed of alkylated diphenylamine and triphenyl phosphite in a weight ratio of 1:(3-5).

10. A method for preparing a non-silicone thermally conductive paste with ultra-low thermal resistance and high temperature resistance as described in any one of claims 1-9, characterized in that, The preparation steps include the following: Ultrafine thermally conductive filler is dispersed in alkylnaphthalene, heated to 120-140℃ and stirred, then cooled to 80-100℃. Alkylbenzene, hydrogenated terphenyl, polyether base oil, structure directing agent, perfluoropolyether phosphate ester and antioxidant are added sequentially. The mixture is then processed by a microfluidic homogenizer under a vacuum of less than 100Pa and a homogenization pressure of 100-150MPa. After vacuum degassing at 60-80℃ and curing for 3-4 hours, a non-silicone thermally conductive paste is obtained.

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