Ternary two-phase filler heat-conducting bonding gel with low thermal resistance and high bonding strength and preparation method of ternary two-phase filler heat-conducting bonding gel

Abstract

The invention discloses a ternary two-phase filler heat-conducting bonding gel with low thermal resistance and high bonding strength and a preparation method of the ternary two-phase filler heat-conducting bonding gel. The high-temperature-resistant silicon rubber is prepared from the following components in parts by weight: 30 to 40 parts of high-viscosity liquid organic silicon rubber, 5 to 10 parts of low-viscosity liquid organic silicon rubber, 0.3 to 0.8 part of hydrogen-containing silicone oil, 0.1 to 0.5 part of an inhibitor, 0.1 to 0.2 part of a microcapsule type platinum catalyst, 0.1 to 0.3 part of a silane coupling agent, 1 to 2 parts of an organic silicon tackifier, 0.05 to 0.1 part of a composite passivator, 0.1 to 0.3 part of an antioxidant, 30 to 40 parts of micron-sized spherical boron nitride powder and 15 to 25 parts of aluminum nitride powder. 1-5 parts of liquid metal gallium, 1-5 parts of metal indium and 1-5 parts of metal tin. On the basis of a spherical boron nitride, liquid metal gallium-indium-tin and spherical aluminum nitride ternary two-phase filler system, BN and AlN serve as solid-phase filler to provide a high-heat-conduction path, Ga-In-Sn alloy serves as an interface between liquid-phase bridging filler, through bridging of the liquid metal Ga-In-Sn alloy, the contact mode between the filler is converted from point-to-point to face-to-face, and the contact mode between the filler and the liquid-phase bridging filler is converted from point-to-point to face-to-face. And dry contact is evolved into a two-phase liquid-solid interface structure, so that the contact thermal resistance is extremely low.

Description

Technical Field

[0001] The invention relates to electronic packaging materials, in particular to a heat-conducting adhesive gel with ternary two-phase filler, low thermal resistance and high bonding strength, and a preparation method thereof. Background Art

[0002] As the power density of AI servers and chips continues to climb, traditional heat dissipation technologies face extreme challenges. Traditional thermal greases have low thermal resistance but lack adhesion, requiring additional mechanical fixation. Silicone gels require high levels of alumina thermal fillers (≥90wt%) to achieve thermal conductivity >5 W / (m·K), but high filling leads to a surge in viscosity, making dispensing difficult and prone to delamination at the bonding interface. Epoxy resin-based thermal adhesives can achieve a shear strength of up to 3 MPa, but the modulus after curing is >1 GPa, resulting in high thermal stress and a tendency to crack delicate electronic components. While silicone gels are flexible, their shear strength is generally <0.5 MPa, failing to meet structural bonding requirements.

[0003] Aluminum nitride (AlN)-based thermal interface materials have become a widely used solution for thermal management in electronic devices due to their high thermal conductivity, high insulation, and easy processing. However, their thermal conductivity is limited by an inherent structural defect: the "point-to-point" dry contact interface formed between solid spherical AlN fillers significantly increases the thermal resistance at the micro- and nanoscale interfaces, which constitutes a core bottleneck in improving the material's thermal performance. To address this issue, spherical boron nitride is used as the primary thermally conductive filler, and spherical AlN powder and gallium-based liquid metal are added to significantly improve the cross-plane thermal conductivity of the target thermal interface material (TIM). A ternary two-phase filler system of spherical boron nitride (BN), liquid metal gallium (Ga), and spherical aluminum nitride (AlN) achieves the synergistic properties of low filler, high thermal conductivity, and high shear strength.

[0004] To address the generally poor shear strength of silicone gels, which cannot meet structural bonding requirements, a composite passivator is firstly developed using rare earth elements (such as gadolinium (Gd) and lanthanum (La)) and hafnium. The oxides of the rare earth elements (Gd / La) have a high lattice match, filling the defects of the hafnium oxide layer and forming a denser three-dimensional network structure. Furthermore, the rare earth ions form coordination bonds with the silicon-oxygen bonds in the silicone matrix, enhancing the interfacial bonding between the liquid metal and the substrate. Secondly, the melting point of the gallium-indium-tin ternary alloy (Ga-In-Sn) can be lowered far below that of pure gallium, while its boiling point is raised. Furthermore, indium and tin form metallic bonds with aluminum nitride and boron nitride, strengthening the interfacial bonding with the filler. Finally, isocyanate groups (-NCO) react with trace hydroxyl and carboxyl groups on the surface of non-polar substrates, forming a three-dimensional covalent bond network of "substrate-adhesion enhancer-substrate," thus overcoming the bonding bottleneck of non-polar substrates. Summary of the Invention

[0005] In response to the problems existing in the prior art, the present invention provides a ternary two-phase filler thermally conductive adhesive gel with low thermal resistance and high bonding strength and a preparation method thereof. The thermally conductive adhesive gel of the present invention has both ultra-low thermal resistance (≤0.15℃·cm² / W) and high bonding strength (≥2.0MPa), and is suitable for thermal management scenarios such as power semiconductor modules, 5G radio frequency chips, and high-density LED packaging. In order to achieve the above-mentioned object, the present invention provides a ternary two-phase filler thermal conductive adhesive gel with low thermal resistance and high bonding strength. The thermal conductive adhesive gel is composed of the following components, by weight: 30-40 parts of high-viscosity liquid silicone rubber, 5-10 parts of low-viscosity liquid silicone rubber, 0.3-0.8 parts of hydrogenated silicone oil, 0.1-0.5 parts of an inhibitor, 0.1-0.2 parts of a microcapsule-type platinum catalyst, 0.1-0.3 parts of a silane coupling agent, 1-2 parts of an organosilicon tackifier, 0.05-0.1 parts of a composite passivator, 0.1-0.3 parts of an antioxidant, 30-40 parts of micron-sized spherical boron nitride powder, 15-25 parts of aluminum nitride powder, 1-5 parts of liquid metal gallium, 1-5 parts of metal indium, and 1-5 parts of metal tin.

[0006] Preferably, the high-viscosity liquid silicone rubber is selected from one or more of double-ended vinyl silicone oil, single-ended vinyl silicone oil, side-chain vinyl silicone oil, and MQ vinyl silicone oil with a viscosity ranging from 100,000 to 800,000 cs.

[0007] Preferably, the low-viscosity liquid silicone rubber is selected from one or more of double-ended vinyl silicone oil, single-ended vinyl silicone oil, and side-chain vinyl silicone oil with a viscosity ranging from 50 to 500 cs.

[0008] Preferably, the hydrogen-containing silicone oil is selected from one or more of methyl-terminated side hydrogen silicone oil, double-terminated hydrogen silicone oil, mixed-chain hydrogen silicone oil, and phenyl side hydrogen silicone oil with a hydrogen content in the range of 0.05-0.18%.

[0009] Preferably, the inhibitor is 3,7,11-trimethyldodecene-3-ol; the capsule particle size of the microcapsule-type platinum catalyst is 50 μm, the softening point is 60° C., and the concentration of the encapsulated chloroplatinic acid catalyst is 2000 ppm.

[0010] Preferably, the silane coupling agent is selected from one or more of methyltrimethoxysilane, vinyltrimethoxysilane, propyltrimethoxysilane, hexadecyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, isocyanatepropyltriethoxysilane, 3-isocyanatepropyltrimethoxysilane, and N-βaminoethyl-γ-aminopropyltrimethoxysilane.

[0011] Preferably, the organosilicon tackifier is selected from one of a silicon boron tackifier and an MQ silicone resin tackifier.

[0012] Preferably, the composite passivator is selected from a complex having a mass ratio of gadolinium:hafnium = 1:3 or a mass ratio of lanthanum:hafnium = 1:4; and the antioxidant is selected from one or more of antioxidant 1010, antioxidant 168, and antioxidant FS042.

[0013] Preferably, the micron-sized spherical boron nitride powder is selected from spherical boron nitride powder with a particle size of 40 μm or spherical boron nitride powder with a particle size of 60 μm; the aluminum nitride powder is selected from spherical aluminum nitride powder with a particle size of 1 μm or spherical aluminum nitride powder with a particle size of 5 μm.

[0014] The present invention also provides a method for preparing the ternary two-phase filler thermal conductive adhesive gel with low thermal resistance and high bonding strength, comprising the following steps: Step S1: melting and alloying liquid metal gallium with metal indium and metal tin at 150° C., and adding a composite passivating agent to pre-generate a dense passivation layer to obtain a liquid metal Ga-In-Sn alloy; Step S2: placing high-viscosity liquid silicone rubber, low-viscosity liquid silicone rubber, hydrogenated silicone oil, inhibitor, silicone tackifier, and antioxidant into a homogenizer, and stirring at 2000 rpm under vacuum for 5 minutes to obtain a base rubber; Step S3: Aluminum nitride powder, silane coupling agent, and liquid metal Ga-In-Sn alloy were added to the base glue, stirred at 2000 rpm in a vacuum for 5 minutes, and then ground with a three-roll mill at a gap of 10 μm to promote the anchoring and spreading of the Ga-In-Sn alloy on the AlN surface; Step S4: Finally, micron-sized spherical boron nitride powder and microcapsule-type platinum catalyst were added, and the mixture was stirred at 1500 rpm in vacuum for 10 minutes to obtain a thermally conductive adhesive gel.

[0015] The technical solution of the present invention has the following beneficial effects: Achieving a synergistic combination of ultra-low thermal resistance and high thermal conductivity: This invention utilizes a ternary, two-phase filler system consisting of spherical boron nitride (BN), liquid metal gallium-indium-tin (Ga-In-Sn), and spherical aluminum nitride (AlN). BN and AlN serve as solid-phase fillers, providing a highly conductive path, while a Ga-In-Sn alloy bridges the filler interface. The liquid metal Ga-In-Sn alloy bridges the gap between the fillers, transforming the contact between the fillers from point-to-point to face-to-face contact and evolving from dry contact to a two-phase liquid-solid interface structure. This results in extremely low contact thermal resistance. A composite passivator forms a dense protective layer to prevent oxidation of the liquid metal. A silane coupling agent and silicone tackifier enhance interfacial bonding, achieving high shear strength.

[0016] The preparation process of the present invention is simple. It achieves both ultra-low thermal resistance (≤0.15℃·cm² / W) and high bonding strength (≥2.0MPa) through the "BN (solid) / Ga-In-Sn (liquid) / AlN (solid)" multiphase system, and a thermal conductivity coefficient of ≥6.0 W / mK, meeting the thermal management requirements of high-power electronic devices, flexible electronics, aerospace and other fields.

[0017] Improve bonding strength to meet structural bonding requirements: Compared with the defect of traditional silicone gel shear strength generally less than 0.5MPa, the present invention constructs a three-dimensional covalent bond network of "substrate-tackifier-matrix" through the synergistic effect of a composite passivator (a composite of rare earth elements and hafnium), an organic silicone tackifier (silicon boron tackifier or MQ silicone resin tackifier) ​​and a silane coupling agent (containing isocyanate groups), making the shear strength ≥2.0MPa. It can replace mechanical fixing methods and is suitable for structural bonding of precision electronic components.

[0018] Solving the problem of liquid metal oxidation and improving stability: Composite passivators (such as gadolinium:hafnium = 1:3, lanthanum:hafnium = 1:4) form a dense passivation layer on the liquid metal surface, effectively inhibiting gallium oxidation during high-temperature curing and preventing the degradation of interfacial bonding caused by oxidation. After 1000 hours of hot and cold cycling testing at -40°C to 150°C, the gel showed no noticeable signs of aging and exhibited significantly better stability than a system without the addition of passivators.

[0019] Balancing workability and compatibility: This system utilizes a combination of high-viscosity and low-viscosity liquid silicone rubbers, and by optimally controlling the filler ratio (total filler content is lower than in traditional systems), it avoids the viscosity surge associated with high filler content, enabling convenient application through dispensing and other processes. Furthermore, the system exhibits excellent compatibility with a variety of electronic component substrates, including power semiconductor modules, 5G RF chips, and high-density LEDs, making it suitable for a wide range of applications. DETAILED DESCRIPTION

[0020] The present invention is further described below with reference to specific embodiments.

[0021] The thermally conductive adhesive gel of this invention is cured via a hydrosilylation reaction. Its preparation involves steps such as base gel preparation, filler dispersion, and catalyst addition. Static relationships, including the proportions and compatibility of the components, ensure system stability. Dynamic relationships, manifested during the stirring, grinding, and curing processes, promote the formation of a "liquid-solid" interface between the fillers. The resulting effect is low thermal resistance and high bonding strength. The specific preparation method is as follows: First, liquid metal gallium (Ga), metal indium (In), and metal tin (Sn) are melted and alloyed at 150°C. A composite passivating agent is then added and stirred to form a dense passivation layer. The static relationship of this step is the lowering of the melting point of the metal alloy and the formation of the passivation layer. The dynamic relationship is the high-temperature melting and stirring, which promotes alloy uniformity. The effect is to prevent oxidation of the liquid metal during the subsequent high-temperature curing and improve the interfacial bonding with the silicone substrate.

[0022] Next, high-viscosity liquid silicone rubber, low-viscosity liquid silicone rubber, hydrogenated silicone oil, inhibitor, silicone tackifier, and antioxidant are placed in a homogenizer and stirred at 2000 rpm under vacuum for 5 minutes to form the base rubber. The static relationship in this step is to achieve mutual solubility and viscosity balance among the components; the dynamic relationship is to ensure bubble-free and uniform dispersion through high-speed stirring under vacuum. The result is a stable matrix, with the inhibitor preventing premature curing and the tackifier improving bonding performance.

[0023] Next, aluminum nitride powder, a silane coupling agent, and the aforementioned liquid metal Ga-In-Sn alloy are added to the base glue and stirred at 2000 rpm under vacuum for 5 minutes. The mixture is then ground using a three-roll mill with a controlled gap of 10 μm. The static effect of this step is to modify the interface between the filler and the matrix. The dynamic effect is that the stirring and mechanical grinding promote the anchoring and spreading of the Ga-In-Sn alloy on the aluminum nitride powder surface, transforming the dry "point-to-point" contact into a "face-to-face" liquid-solid interface. The result is a reduction in contact thermal resistance and improved thermal conductivity.

[0024] Finally, micron-sized spherical boron nitride powder and microencapsulated platinum catalyst were added to the mixture and stirred at 1500 rpm for 10 minutes under vacuum to produce a thermally conductive adhesive gel. This step statically constructs the final filler network; dynamically, stirring at low speed prevents damage to the microcapsules. The result is a ternary, two-phase filler system, achieving high thermal conductivity and excellent adhesion.

[0025] During use, the gel is squeezed out and placed between the chip and the heat sink. A pressure of 50 PSI is applied, and the gel is heated at 80°C for 30 minutes to cure. During the curing process, when the temperature exceeds 60°C, the microcapsules of the platinum catalyst soften, releasing the platinum catalyst to initiate hydrosilylation polymerization, forming a strong bond between the chip and the heat sink.

[0026] Example 1 The following were taken by weight: 30 parts of bi-terminal vinyl silicone oil with a viscosity of 100,000 cs, 9 parts of bi-terminal vinyl silicone oil with a viscosity of 50 cs, 0.4 parts of phenyl hydrogen silicone oil, 0.2 parts of 3,7,11-trimethyldodecyn-3-ol (inhibitor), 1 part of silicon boron tackifier, and 0.1 parts of antioxidant 1010, placed in a homogenizer and stirred at high speed under vacuum for 5 minutes (2000 rpm) to obtain a base rubber.

[0027] 4 parts of liquid metal gallium, 1 part of metal indium, and 1 part of metal tin are melted and alloyed at 150°C, and 0.05 parts of a composite passivator (gadolinium:hafnium=1:3) are added and stirred evenly to pre-generate a dense passivation layer to obtain a liquid metal Ga-In-Sn alloy.

[0028] Add 18 parts of spherical aluminum nitride powder with a particle size of 5 μm, 0.3 parts of 3-isocyanatepropyltrimethoxysilane (silane coupling agent) and the above-mentioned Ga-In-Sn alloy to the base glue, stir at high speed in vacuum for 5 minutes (2000 rpm), and then grind with a three-roll mill (gap 10 μm).

[0029] Finally, 35 parts of spherical boron nitride powder with a particle size of 40 μm and 0.1 parts of microcapsule platinum catalyst (capsule particle size of 50 μm, softening point of 60°C, encapsulation concentration of 2000 ppm chloroplatinic acid catalyst) were added, and vacuum high-speed stirring was carried out for 10 minutes (1500 rpm) to obtain a thermal conductive adhesive gel.

[0030] Example 2 Calculate the following by weight: 30 parts of bi-terminal vinyl silicone oil with a viscosity of 100,000 cs, 9 parts of bi-terminal vinyl silicone oil with a viscosity of 50 cs, 0.4 parts of phenyl hydrogen silicone oil, 0.2 parts of 3,7,11-trimethyldodecyl-3-ol, 1 part of silicon boron tackifier, and 0.1 parts of antioxidant 1010, place them in a homogenizer and stir them at high speed under vacuum for 5 minutes (2000 rpm) to obtain a base rubber.

[0031] Add 18 parts of spherical aluminum nitride powder with a particle size of 5 μm and 0.3 parts of 3-isocyanatepropyltrimethoxysilane to the base rubber, stir at high speed in vacuum for 5 minutes (2000 rpm), and then grind with a three-roll mill (gap 10 μm).

[0032] Finally, 35 parts of spherical boron nitride powder with a particle size of 40 μm and 0.1 parts of microcapsule-type platinum catalyst were added, and the mixture was stirred at a high speed in vacuum for 10 minutes (1500 rpm) to obtain a thermally conductive adhesive gel.

[0033] This example does not add liquid metal Ga-In-Sn alloy, and is used to compare the effect of the interface structure between fillers on the performance.

[0034] Example 3 The following were taken by weight: 30 parts of bi-terminal vinyl silicone oil with a viscosity of 100,000 cs, 9 parts of bi-terminal vinyl silicone oil with a viscosity of 50 cs, 0.4 parts of phenyl hydrogen silicone oil, 0.2 parts of 3,7,11-trimethyldodecene-3-ol, 1 part of MQ silicone resin tackifier, and 0.1 parts of antioxidant 1010, placed in a homogenizer and stirred at high speed under vacuum for 5 minutes (2000 rpm) to obtain a base rubber.

[0035] 4 parts of liquid metal gallium, 1 part of metal indium, and 1 part of metal tin are melted and alloyed at 150°C, and 0.05 parts of a composite passivating agent (gadolinium:hafnium=1:3) are added and stirred evenly to obtain a liquid metal Ga-In-Sn alloy.

[0036] Add 18 parts of spherical aluminum nitride powder with a particle size of 5 μm, 0.3 parts of 3-isocyanatepropyltrimethoxysilane and the above-mentioned Ga-In-Sn alloy to the base glue, stir at high speed in vacuum for 5 minutes (2000 rpm), and then grind with a three-roll mill (gap 10 μm).

[0037] Finally, 35 parts of spherical boron nitride powder with a particle size of 40 μm and 0.1 parts of microcapsule-type platinum catalyst were added, and the mixture was stirred at a high speed in vacuum for 10 minutes (1500 rpm) to obtain a thermally conductive adhesive gel.

[0038] This example uses MQ silicone resin tackifier to compare the effects of different tackifiers on shear strength.

[0039] Example 4 Calculate the following by weight: 30 parts of bi-terminal vinyl silicone oil with a viscosity of 100,000 cs, 9 parts of bi-terminal vinyl silicone oil with a viscosity of 50 cs, 0.4 parts of phenyl hydrogen silicone oil, 0.2 parts of 3,7,11-trimethyldodecyl-3-ol, 1 part of silicon boron tackifier, and 0.1 parts of antioxidant 1010, place them in a homogenizer and stir them at high speed under vacuum for 5 minutes (2000 rpm) to obtain a base rubber.

[0040] 4 parts of liquid metal gallium, 1 part of metal indium, and 1 part of metal tin are melted and alloyed at 150°C, and 0.05 parts of a composite passivating agent (gadolinium:hafnium=1:3) are added and stirred evenly to obtain a liquid metal Ga-In-Sn alloy.

[0041] Add 18 parts of spherical aluminum nitride powder with a particle size of 5 μm, 0.3 parts of vinyltrimethoxysilane (silane coupling agent) and the above-mentioned Ga-In-Sn alloy to the base glue, stir at high speed in vacuum for 5 minutes (2000 rpm), and then grind with a three-roll grinder (gap 10 μm).

[0042] Finally, 35 parts of spherical boron nitride powder with a particle size of 40 μm and 0.1 parts of microcapsule-type platinum catalyst were added, and the mixture was stirred at a high speed in vacuum for 10 minutes (1500 rpm) to obtain a thermally conductive adhesive gel.

[0043] This example uses vinyltrimethoxysilane to compare the effects of different silane coupling agents on bonding performance.

[0044] Example 5 Calculate the following by weight: 30 parts of bi-terminal vinyl silicone oil with a viscosity of 100,000 cs, 9 parts of bi-terminal vinyl silicone oil with a viscosity of 50 cs, 0.4 parts of phenyl hydrogen silicone oil, 0.2 parts of 3,7,11-trimethyldodecyl-3-ol, 1 part of silicon boron tackifier, and 0.1 parts of antioxidant 1010, place them in a homogenizer and stir them at high speed under vacuum for 5 minutes (2000 rpm) to obtain a base rubber.

[0045] 4 parts of liquid metal gallium, 1 part of metal indium, and 1 part of metal tin are melted and alloyed at 150°C, and 0.05 parts of a composite passivating agent (gadolinium:hafnium=1:3) are added and stirred evenly to obtain a liquid metal Ga-In-Sn alloy.

[0046] Add 18 parts of spherical alumina powder with a particle size of 5 μm, 0.3 parts of 3-isocyanatepropyltrimethoxysilane and the above-mentioned Ga-In-Sn alloy to the base glue, stir at high speed in vacuum for 5 minutes (2000 rpm), and then grind with a three-roll mill (gap 10 μm).

[0047] Finally, 35 parts of spherical boron nitride powder with a particle size of 40 μm and 0.1 parts of microcapsule-type platinum catalyst were added, and the mixture was stirred at a high speed in vacuum for 10 minutes (1500 rpm) to obtain a thermally conductive adhesive gel.

[0048] This example uses aluminum oxide powder instead of aluminum nitride powder to compare the effects of different fillers on thermal conductivity.

[0049] Example 6 Calculate the following by weight: 30 parts of bi-terminal vinyl silicone oil with a viscosity of 100,000 cs, 9 parts of bi-terminal vinyl silicone oil with a viscosity of 50 cs, 0.4 parts of phenyl hydrogen silicone oil, 0.2 parts of 3,7,11-trimethyldodecyl-3-ol, 1 part of silicon boron tackifier, and 0.1 parts of antioxidant 1010, place them in a homogenizer and stir them at high speed under vacuum for 5 minutes (2000 rpm) to obtain a base rubber.

[0050] 4 parts of liquid metal gallium, 1 part of metal indium, and 1 part of metal tin are melted and alloyed at 150° C. to obtain a liquid metal Ga-In-Sn alloy (without adding a composite passivating agent).

[0051] Add 18 parts of spherical aluminum nitride powder with a particle size of 5 μm, 0.3 parts of 3-isocyanatepropyltrimethoxysilane and the above-mentioned Ga-In-Sn alloy to the base glue, stir at high speed in vacuum for 5 minutes (2000 rpm), and then grind with a three-roll mill (gap 10 μm).

[0052] Finally, 35 parts of spherical boron nitride powder with a particle size of 40 μm and 0.1 parts of microcapsule-type platinum catalyst were added, and the mixture was stirred at a high speed in vacuum for 10 minutes (1500 rpm) to obtain a thermally conductive adhesive gel.

[0053] This example does not add a composite passivating agent and is used to compare the effect of the passivation layer on the aging resistance.

[0054] The thermally conductive adhesive gels prepared in Examples 1-6 were tested for performance, and the results are shown in Table 1 below:

[0055] As shown in Table 1, comparing Example 1 and Example 2, it can be found that there is no liquid metal Ga-In-Sn alloy bridge between BN / AlN, and the contact mode between the fillers becomes a "point-to-point" and "solid-solid" interface structure, and the thermal resistance increases significantly.

[0056] Comparing Example 1 and Example 3, it can be found that the MQ silicone resin tackifier significantly improves the bonding shear strength, indicating that the MQ siloxane functional group can react with the active groups (such as hydroxyl, amino, etc.) on the surface of the substrate to form a more stable bonding layer.

[0057] Comparing Example 1 with Example 4, it can be found that no isocyanate group (-NCO) reacts with the trace hydroxyl and carboxyl groups on the surface of the non-polar substrate to form a three-dimensional covalent bond network of "substrate-tackifier-matrix", and the bonding strength of the gel is significantly reduced.

[0058] Comparing Example 1 and Example 5, it can be found that the thermal conductivity of aluminum oxide is slightly worse than that of aluminum nitride. However, liquid gallium can fill the 10nm-1μm gaps autonomously through the capillary effect, reducing the interfacial contact thermal resistance, so the overall thermal resistance of the gel will not increase significantly.

[0059] By comparing Example 1 and Example 6, it can be found that no dense passivation layer is formed on the surface of the liquid metal Ga-In-Sn alloy. Under high temperature conditions, metal Ga is easily oxidized, resulting in the breaking of the coordination bond formed between the silicon-oxygen bond in the organic silicon and the metal surface, the loss of bonding force at the interface between the liquid metal and the substrate, and accelerated aging of the colloid.

[0060] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention specification under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A thermally conductive adhesive gel with low thermal resistance and high bonding strength containing ternary two-phase fillers, characterized in that: The invention is composed of the following components by weight: 30-40 parts of high-viscosity liquid silicone rubber, 5-10 parts of low-viscosity liquid silicone rubber, 0.3-0.8 parts of hydrogenated silicone oil, 0.1-0.5 parts of inhibitor, 0.1-0.2 parts of microcapsule-type platinum catalyst, 0.1-0.3 parts of silane coupling agent, 1-2 parts of silicone tackifier, 0.05-0.1 parts of composite passivator, 0.1-0.3 parts of antioxidant, 30-40 parts of micron-sized spherical boron nitride powder, 15-25 parts of aluminum nitride powder, 1-5 parts of liquid metal gallium, 1-5 parts of metal indium, and 1-5 parts of metal tin.

2. The thermally conductive adhesive gel with low thermal resistance and high bonding strength of the ternary two-phase filler according to claim 1, characterized in that: The high-viscosity liquid silicone rubber is selected from one or more of double-ended vinyl silicone oil, single-ended vinyl silicone oil, side-chain vinyl silicone oil, and MQ vinyl silicone oil with a viscosity ranging from 100,000 to 800,000 cs.

3. The thermally conductive adhesive gel with low thermal resistance and high bonding strength of the ternary two-phase filler according to claim 1, characterized in that: The low-viscosity liquid silicone rubber is selected from one or more of double-ended vinyl silicone oil, single-ended vinyl silicone oil, and side-chain vinyl silicone oil with a viscosity ranging from 50 to 500 cs.

4. The thermally conductive adhesive gel with low thermal resistance and high bonding strength of the ternary two-phase filler according to claim 1, characterized in that: The hydrogen-containing silicone oil is selected from one or more of methyl-terminated side hydrogen silicone oil, double-terminated hydrogen silicone oil, mixed chain hydrogen silicone oil, and phenyl side hydrogen silicone oil with a hydrogen content in the range of 0.05-0.18%.

5. The thermally conductive adhesive gel with low thermal resistance and high bonding strength of the ternary two-phase filler according to claim 1, characterized in that: The inhibitor is 3,7,11-trimethyldodecene-3-ol; the capsule particle size of the microcapsule-type platinum catalyst is 50 μm, the softening point is 60° C., and the concentration of the encapsulated chloroplatinic acid catalyst is 2000 ppm.

6. The thermally conductive adhesive gel with low thermal resistance and high bonding strength of the ternary two-phase filler according to claim 1, characterized in that: The silane coupling agent is selected from one or more of methyltrimethoxysilane, vinyltrimethoxysilane, propyltrimethoxysilane, hexadecyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, isocyanatepropyltriethoxysilane, 3-isocyanatepropyltrimethoxysilane, and N-βaminoethyl-γ-aminopropyltrimethoxysilane.

7. The thermally conductive adhesive gel with low thermal resistance and high bonding strength of the ternary two-phase filler according to claim 1, characterized in that: The organosilicon tackifier is selected from one of a silicon boron tackifier and an MQ silicone resin tackifier.

8. The thermally conductive adhesive gel with low thermal resistance and high bonding strength containing ternary two-phase fillers according to claim 1, characterized in that: The composite passivator is selected from a compound having a mass ratio of gadolinium to hafnium of 1:3 or a mass ratio of lanthanum to hafnium of 1:4; and the antioxidant is selected from one or more of antioxidant 1010, antioxidant 168, and antioxidant FS042.

9. The thermally conductive adhesive gel with low thermal resistance and high bonding strength containing ternary two-phase fillers according to claim 1, characterized in that: The micron-sized spherical boron nitride powder is selected from spherical boron nitride powder with a particle size of 40 μm or spherical boron nitride powder with a particle size of 60 μm; the aluminum nitride powder is selected from spherical aluminum nitride powder with a particle size of 1 μm or spherical aluminum nitride powder with a particle size of 5 μm.

10. A method for preparing a thermally conductive adhesive gel with low thermal resistance and high bonding strength containing a ternary two-phase filler according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step S1: melting and alloying liquid metal gallium with metal indium and metal tin at 150° C., and adding a composite passivating agent to pre-generate a dense passivation layer to obtain a liquid metal Ga-In-Sn alloy; Step S2: placing high-viscosity liquid silicone rubber, low-viscosity liquid silicone rubber, hydrogenated silicone oil, inhibitor, silicone tackifier, and antioxidant into a homogenizer, and stirring at 2000 rpm under vacuum for 5 minutes to obtain a base rubber; Step S3: Aluminum nitride powder, silane coupling agent, and liquid metal Ga-In-Sn alloy were added to the base glue, stirred at 2000 rpm in a vacuum for 5 minutes, and then ground with a three-roll mill at a gap of 10 μm to promote the anchoring and spreading of the Ga-In-Sn alloy on the AlN surface; Step S4: Finally, micron-sized spherical boron nitride powder and microcapsule-type platinum catalyst were added, and the mixture was stirred at 1500 rpm in vacuum for 10 minutes to obtain a thermally conductive adhesive gel.

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