Heat-conducting, insulating and impact-hardening-resistant rubber as well as preparation method and application thereof

Abstract

The invention relates to heat-conducting, insulating and impact-hardening-resistant rubber as well as a preparation method and application thereof. The preparation raw materials of the heat-conducting insulating shock-resistant hardened rubber comprise a silicone rubber matrix, a filler, a reinforcing auxiliary agent, a silane coupling agent and a temperature-sensitive phase change microcapsule, the filler comprises nano aluminum oxide and micron boron nitride. The heat-conducting, insulating and impact-hardening-resistant rubber provided by the invention has excellent comprehensive properties of efficient heat conduction, high insulativity, rapid impact hardening and reliable interface bonding, and can effectively solve the problems of thermal failure and mechanical damage of a power type controller under severe impact when being applied to a potting process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of non-Newtonian fluid materials, in particular to a heat-conducting, insulating and impact-hardening rubber as well as a preparation method and application thereof. BACKGROUND

[0002] In the field of new energy automobile suspension motor controllers, avionics, unmanned aerial vehicles and the like, the miniaturization and high power density of electronic components lead to the core challenge of thermal-electric-mechanical coupling failure, which mainly has the following difficulties:

[0003] (1) Balance problem of heat conduction and insulation: the thermal conductivity coefficient of traditional silicone rubber potting materials is generally less than 1.5 W / (m·K), which is difficult to meet the chip junction temperature control requirement (such as the surface temperature of power devices > 120℃). Although the introduction of high thermal conductivity fillers (such as silicon carbide, boron nitride) can improve the thermal conductivity, the intrinsic conductivity or interface defects of such fillers easily lead to the degradation of insulation performance (volume resistivity < 10 12 Ω·cm), which cannot meet the insulation requirements in a high-voltage environment.

[0004] (2) Insufficient strain rate sensitivity of impact protection: conventional elastomer materials exhibit elastic deformation under low-speed impact, but in the face of high-speed impact (strain rate > 10 2 s -1 , such as peak acceleration > 50 g in the vehicle suspension scene), they lack effective energy dissipation mechanisms and are prone to brittle fracture or interfacial debonding. Traditional impact-resistant materials (such as epoxy resin) are too rigid to achieve the adaptive response of "low-load flexible cushioning and high-load rigid support", and the impact energy absorption rate is usually less than 70% and the reaction time is > 10 ms.

[0005] In summary, how to simultaneously achieve efficient heat conduction, high insulation, strain rate sensitive impact hardening and low-cost processability through filler system design and interface engineering is a technical difficulty in the current electronic packaging field. Therefore, it is of great significance to design and provide a heat-conducting, insulating and impact-hardening rubber with high performance. SUMMARY

[0006] To solve the above technical problems, the present application provides a heat-conducting, insulating and impact-hardening rubber as well as a preparation method and application thereof. When the heat-conducting, insulating and impact-hardening rubber is applied in a potting process, it can realize the comprehensive performance improvement of efficient heat conduction, high insulation, rapid impact hardening and reliable interface bonding of the final product.

[0007] To achieve this purpose, the present application adopts the following technical solutions:

[0008] In a first aspect, the present application provides a heat-conducting, insulating and impact-hardening rubber, and the raw materials for preparing the heat-conducting, insulating and impact-hardening silicone rubber include a silicone rubber matrix, a filler, a reinforcing aid, a silane coupling agent and temperature-sensitive phase change microcapsules; the filler includes nano-aluminum oxide (nano-Al2O3) and micron boron nitride (micron BN).

[0009] The heat-conducting, insulating and impact-hardening rubber of the present application is prepared by using a multi-scale filler (nano-micron filler combination), a reinforcing aid, temperature-sensitive phase change microcapsules and a silicone rubber matrix, and impact hardening is achieved through a strain rate sensitive shear thickening mechanism, so that the heat-conducting, insulating and impact-hardening rubber has the non-Newtonian fluid characteristics of low viscosity flow in normal state and rapid hardening in impact, and when it is applied to a potting process, it can effectively solve the technical problems of thermal failure, mechanical damage and insulation failure of high-power-density electronic devices in a vibration, impact, high-temperature and high-voltage environment, and is suitable for scenes with high reliability requirements such as vehicle-mounted, aerospace, unmanned aerial vehicle industrial automation, etc.

[0010] In the present application, nano ceramic particles (nano-Al2O3) and micron heat-conducting sheet layers (micron BN) are used as fillers and reinforcing aids to form a multi-scale filler synergistic reinforcing system, which well constructs a gradient structure, improves the continuity of the heat-conducting path, and inhibits the formation of conductive channels, so that the obtained rubber material has excellent heat-conducting and insulating properties; further, by combining temperature-sensitive phase change microcapsules with multi-scale fillers, an adaptive response mechanism of "low-speed flexible flow, high-speed rigid locking" can be constructed, the strain rate limitation of traditional elastomer impact protection is broken through, and the obtained rubber material has good impact resistance, solving the problem of slow impact response speed of traditional rubber due to the insufficient strain rate sensitivity of elastomer.

[0011] The following is a preferred technical scheme of the present application, but is not a limitation on the technical scheme provided by the present application. Through the following preferred technical scheme, the purpose and beneficial effects of the present application can be better achieved and realized.

[0012] As a preferred technical scheme of the present application, the raw materials for preparing the heat-conducting, insulating and impact-hardening rubber include the following components in the following weight fractions:

[0013] 100 parts of silicone rubber matrix;

[0014] 10-20 parts of nano-aluminum oxide;

[0015] 15-30 parts of micron boron nitride;

[0016] 5-10 parts of reinforcing aid;

[0017] 1.5-3.5 parts of silane coupling agent;

[0018] 0.5-2 parts of temperature-sensitive phase change microcapsules.

[0019] The weight fraction of the nano-aluminum oxide in the preparation raw material of the heat-conducting, insulating, impact-resistant and hardened rubber can be 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts or 20 parts, etc., the weight fraction of the micron boron nitride can be 15 parts, 18 parts, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts or 30 parts, etc., the weight fraction of the reinforcing aid can be 5 parts, 5.5 parts, 6 parts, 6.5 parts, 7 parts, 7.5 parts, 8 parts, 8.5 parts, 9 parts, 9.5 parts or 10 parts, etc., the weight fraction of the silane coupling agent can be 1.5 parts, 1.8 parts, 2 parts, 2.2 parts, 2.5 parts, 2.8 parts, 3 parts, 3.2 parts or 3.5 parts, etc., and the weight fraction of the temperature-sensitive phase change microcapsule can be 0.5 parts, 0.8 parts, 1 part, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts or 2 parts, etc.

[0020] As a preferred technical solution of the present application, the micron boron nitride comprises at least one micron boron nitride with an average particle size of 1-10 μm, for example, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or 10 μm, etc.

[0021] In the present application, the use of fillers (nano Al2O3 and micron BN) with specific content can make the obtained heat-conducting, insulating, impact-resistant and hardened rubber be a low-viscosity fluid (viscosity < 5000 mPa·s) in normal state, facilitating the filling and penetration, and under impact load (strain rate 10 2 -10 4 s -1 ), the nanoparticles and micron sheets form a transient rigid network through the "friction-engagement" effect, the viscosity increases sharply, and a self-adaptive response of "liquid filling-solid protection" is well formed, effectively solving the filling defects (such as air holes and stress concentration) of traditional rigid materials, and significantly improving the impact resistance.

[0022] As a preferred technical solution of the present application, the micron boron nitride is selected from the group consisting of low-particle-size micron boron nitride and high-particle-size micron boron nitride.

[0023] In the present application, the low-particle-size micron boron nitride and the high-particle-size micron boron nitride are compounded to form dual-particle-size boron nitride, which can well make the two play a synergistic effect, thereby constructing a dual-functional structure of "tightly packed + heat-conducting network", improving the continuity of the heat-conducting path, and further making the obtained heat-conducting, insulating, impact-resistant and hardened rubber have more excellent heat-conducting performance.

[0024] Preferably, the average particle size of the low-particle-size micron-sized boron nitride is 1-3 μm, for example, it can be 1 μm, 1.2 μm, 1.5 μm, 1.8 μm, 2 μm, 2.2 μm, 2.5 μm, 2.8 μm, or 3 μm, etc.

[0025] Preferably, the average particle size of the high-particle-size micron-sized boron nitride is 7-9 μm, for example, it can be 7 μm, 7.2 μm, 7.5 μm, 7.8 μm, 8 μm, 8.2 μm, 8.5 μm, 8.8 μm, or 9 μm, etc.

[0026] As a preferred technical solution of the present application, the mass ratio of the low-particle-size micron-sized boron nitride and the high-particle-size micron-sized boron nitride is (1.5-2.5):1, for example, it can be 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, or 2.5:1, etc.

[0027] The present application can further improve the thermal conductivity of the obtained heat-conducting and insulating impact-hardened rubber by optimizing the mass ratio of the low-particle-size micron-sized boron nitride and the high-particle-size micron-sized boron nitride.

[0028] When the mass ratio is low, i.e., the proportion of low-particle-size micron-sized boron nitride is low, a large number of large-particle-size boron nitrides will form large voids. Since the amount of small-particle-size boron nitride is insufficient, it cannot effectively fill these voids, resulting in low packing density of the filler. When the heat flow passes through, it needs to frequently cross the poor thermal conductivity silicone rubber matrix ("thermal barrier"), and the overall heat conduction path is not smooth, thereby reducing the thermal conductivity of the obtained rubber material. In addition, large-particle-size boron nitride acts as a stress concentration point in the silicone rubber matrix, and is more likely to cause cracks. When impacted, the cracks are more likely to expand from the large-particle-size interface, thereby reducing the impact strength, tensile strength, and elongation at break of the obtained rubber product, and making the material more brittle. At the same time, large-particle-size boron nitride can cause the surface of the product to be rougher.

[0029] When the mass ratio is high, i.e., the proportion of low-particle-size micron-sized boron nitride is high, the viscosity of the system rises sharply, and the processability deteriorates extremely. The reason is that small-particle-size boron nitride has a very high specific surface area, and more polymer molecular chains are needed to wet and wrap them, resulting in an exponential increase in the viscosity of the rubber material melt or compound system. As a result, the compound becomes very hard and dry, making it difficult to stir, mix, deaerate, and pour into shape. In severe cases, it cannot be processed at all. In addition, although excessive small-particle-size boron nitride can form a large number of heat-conducting points, it lacks sufficient large-particle-size boron nitride as the "main road" to connect these "branches", and is prone to form local and isolated heat-conducting clusters, which limits the improvement of the macroscopic heat conduction efficiency, thereby reducing the efficiency of improving the thermal conductivity of the obtained rubber material and the cost performance.

[0030] As a preferred technical solution of the present application, the reinforcing aid comprises micron alumina (Al2O3) and / or silicon carbide (SiC) with a core-shell structure.

[0031] The use of the reinforcing aid in the present application can significantly improve the insulation performance of the obtained heat-conducting and insulation impact-hardened rubber. By compounding it with the filler, the heat-conducting-insulation balance of the obtained material can be well adjusted, and the contradiction between heat conduction and insulation is solved. The coating layer of the silicon carbide with a core-shell structure can isolate the conductive path of the high-thermal-conductivity filler silicon carbide, thereby overcoming the defect of high risk of metal-based filler leakage in traditional rubber, and making the obtained heat-conducting and insulation impact-resistant rubber have excellent insulation performance. The micron alumina has low cost and excellent insulation performance, which is conducive to promoting the popularization of the heat-conducting and insulation impact-hardened rubber, and has high economic benefit and strong practicality.

[0032] Preferably, the average particle size of the micron alumina is 3-8 μm, for example, it can be 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.8 μm or 8 μm, etc.

[0033] Preferably, the average particle size of the silicon carbide with a core-shell structure is 1-3 μm, for example, it can be 1 μm, 1.2 μm, 1.4 μm, 1.6 μm, 1.8 μm, 2 μm, 2.2 μm, 2.4 μm, 2.6 μm, 2.8 μm or 3 μm, etc.

[0034] Preferably, the silicon carbide with a core-shell structure comprises a silicon carbide core and a coating layer.

[0035] Preferably, the thickness of the coating layer is 50-130 nm, for example, it can be 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm or 130 nm, etc.

[0036] Preferably, the coating layer is a silicon dioxide coating layer or an alumina-silicon dioxide composite coating layer.

[0037] In the present application, when the composite coated silicon carbide with an oxide-oxide core-shell structure is used, it can better optimize the surface polarity of the filler, thereby reducing the interface defects better, and further adjusting the high thermal conductivity and insulation performance. Further, by matching with other components, the impact resistance of the obtained heat-conducting and insulation impact-hardened rubber can be better improved.

[0038] It should be noted that when the coating layer is a silicon dioxide coating layer, the silicon carbide with a core-shell structure is SiO2 coated SiC (SiO2@SiC); when the coating layer is an aluminum oxide-silicon dioxide composite coating silicon carbide layer, the silicon carbide with a core-shell structure is Al2O3@SiO2 composite coated SiC (SiO2@Al2O3@SiC).

[0039] Preferably, when the coating layer is a silicon dioxide coating layer, the mass percentage of the silicon carbide core is ≥90%, for example, it can be 90%, 90.5%, 91%, 91.5%, 92%, 92.5%, 93%, 93.5%, 94%, 94.5% or 95%, etc., based on 100% of the mass percentage of the silicon carbide with a core-shell structure.

[0040] Preferably, the thickness of the silicon dioxide coating layer is 50-80 nm, for example, it can be 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm or 80 nm, etc.

[0041] Preferably, the aluminum oxide-silicon dioxide composite coating layer includes an inner layer of aluminum oxide and an outer layer of silicon dioxide.

[0042] Preferably, the thickness of the inner layer of aluminum oxide in the aluminum oxide-silicon dioxide composite coating layer is 30-50 nm, for example, it can be 30 nm, 32 nm, 34 nm, 36 nm, 38 nm, 40 nm, 42 nm, 44 nm, 46 nm, 48 nm or 50 nm, etc.

[0043] Preferably, the thickness of the outer layer of silicon dioxide in the aluminum oxide-silicon dioxide composite coating layer is 30-80 nm, for example, it can be 30 nm, 40 nm, 50 nm, 60 nm, 70 nm or 80 nm, etc.

[0044] Preferably, the average particle size of the nano-aluminum oxide is 30-100 nm, for example, it can be 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm or 100 nm, etc.

[0045] Preferably, the surface hydroxyl coverage of the nano-aluminum oxide is ≥95%, for example, it can be 95%, 95.5%, 96%, 96.5%, 97%, 97.5%, 98%, 98.5% or 99%, etc.

[0046] Preferably, the silicone rubber matrix includes a vinyl silicone rubber matrix.

[0047] Preferably, the vinyl content in the vinyl silicone rubber matrix is greater than or equal to 0.2 mol%, for example, it can be 0.2 mol%, 0.22 mol%, 0.25 mol%, 0.28 mol%, 0.3 mol%, 0.32 mol%, 0.35 mol%, 0.38 mol%, or 0.4 mol%, etc.

[0048] Preferably, the silane coupling agent comprises KH-560.

[0049] As a preferred technical solution of the present application, the temperature-sensitive phase change microcapsule comprises a core material and a shell material.

[0050] Preferably, the core material of the temperature-sensitive phase change microcapsule comprises paraffin and / or octadecane.

[0051] Preferably, the shell material of the temperature-sensitive phase change microcapsule comprises an elastomer.

[0052] In the temperature-sensitive phase change microcapsule of the present application, the core material is the phase change material paraffin and / or octadecane, and the shell material is an elastomer. Through the synergistic effect of latent heat of phase change and elastic deformation of the two, multi-stage dissipation of impact energy can be achieved, thereby improving the strain rate sensitivity. Through the collocation with other components, the obtained heat-conducting and insulating impact-resistant hardened rubber can have a viscosity increase of 3-4 orders of magnitude in a strain rate range of 10 2 -10 4 s -1 , a significant improvement in impact energy absorption rate, while maintaining a wide range of performance adjustment capability of volume resistivity greater than or equal to 10 12 Ω·cm, and thermal conductivity of 1.0-3.5 W / (m·K). At the same time, the addition of the temperature-sensitive phase change microcapsule can also effectively improve the impact fatigue and temperature fatigue of the obtained product, produce self-repairing of internal cracks of the gel, thereby significantly improving the durability of the obtained heat-conducting and insulating impact-resistant hardened rubber.

[0053] Preferably, the preparation raw material of the heat-conducting and insulating impact-resistant hardened rubber further comprises a catalyst.

[0054] In the present application, the catalyst is mainly used for catalytic crosslinking of the silicone rubber matrix during the curing process, which is beneficial to form a three-dimensional crosslinked network structure, so that the obtained material changes from a fluid state to a hardened rubber state with elasticity and impact resistance, thereby making the obtained rubber material have excellent impact resistance, adhesion, and other mechanical properties.

[0055] It should be noted that the type of catalyst in the present application is not particularly limited, and the catalyst commonly used in the art is suitable, exemplarily including but not limited to platinum catalyst.

[0056] Preferably, the weight fraction of the catalyst in the preparation raw material of the heat-conducting, insulating, impact-resistant and hardened rubber is 0.01-0.05 parts, for example, it can be 0.01 parts, 0.015 parts, 0.02 parts, 0.025 parts, 0.03 parts, 0.035 parts, 0.04 parts, 0.045 parts or 0.05 parts, etc.

[0057] In a second aspect, the present application provides a preparation method of the heat-conducting, insulating, impact-resistant and hardened rubber according to the first aspect, the preparation method comprising the following steps:

[0058] The silicon rubber matrix, the filler, the reinforcing aid and the silane coupling agent are mixed to obtain a preliminary premix, and then the temperature-sensitive phase change microcapsules and the optional catalyst are added to obtain the heat-conducting, insulating, impact-resistant and hardened rubber.

[0059] Preferably, the mixing is carried out under stirring.

[0060] Preferably, the stirring speed is 100-200 rpm, for example, it can be 100 rpm, 110 rpm, 120 rpm, 130 rpm, 140 rpm, 150 rpm, 160 rpm, 170 rpm, 180 rpm, 190 rpm or 200 rpm, etc.

[0061] It should be noted that, in actual operation, in order to ensure that the components are fully mixed without agglomeration, the filler, the reinforcing aid, the temperature-sensitive phase change microcapsules and the optional catalyst can be added in batches (such as in 2 batches), and after adding each component, stirring for 10-15 min (for example, it can be 10 min, 11 min, 12 min, 13 min, 14 min or 15 min, etc.) before the next addition.

[0062] Preferably, the mixing is carried out in a planetary mixer.

[0063] Preferably, the temperature of the planetary mixer is 40-50℃, for example, it can be 40℃, 42℃, 44℃, 46℃, 48℃ or 50℃, etc.

[0064] Preferably, the silicon rubber matrix, the filler and the reinforcing aid each include a pretreatment step before mixing.

[0065] Preferably, the pretreatment of the silicon rubber matrix includes plasticizing the silicon rubber matrix.

[0066] The present application plasticizes the silicon rubber matrix, which aims to eliminate internal stress of the rubber, improve the uniformity of subsequent filler mixing, and avoid dispersion defects caused by uneven matrix elasticity.

[0067] It should be noted that the present application does not have special limitations on the specific selection of the temperature and time of plasticizing, and is adaptively adjusted according to the selection of specific materials, exemplarily including but not limited to: the temperature of plasticizing is 50-60℃ (for example, it can be 50℃, 51℃, 52℃, 53℃, 54℃, 55℃, 56℃, 57℃, 58℃, 59℃ or 60℃, etc.), and the time is 5-8min (for example, it can be 5min, 5.5min, 6min, 6.5min, 7min, 7.5min or 8min, etc.).

[0068] Preferably, the pretreatment of the filler includes the pretreatment of nano-alumina and the pretreatment of micron-boron nitride.

[0069] Preferably, the pretreatment of the nano-alumina includes modifying the nano-alumina by the following steps:

[0070] After dispersing and mixing the nano-alumina and the silane coupling agent solution at a solid-liquid ratio of 1:(3-5) (for example, it can be 1:3, 1:3.2, 1:3.5, 1:3.8, 1:4, 1:4.2, 1:4.5, 1:4.8 or 1:5, etc.), drying and sieving, the modified nano-alumina is obtained.

[0071] It should be noted that the solid-liquid ratio in the present application refers to the mass ratio. In the present application, both the modified nano-alumina obtained by pretreating the commercially available nano-alumina and the commercially available product modified by the silane coupling agent can be directly used.

[0072] Preferably, the coupling agent solution is prepared by mixing the silane coupling agent and ethanol at a mass ratio of 1:(25-40) (for example, it can be 1:25, 1:28, 1:30, 1:32, 1:34, 1:36, 1:38 or 1:40, etc.).

[0073] Preferably, the dispersing and mixing is carried out under stirring.

[0074] Preferably, the stirring speed is 1500-2000 rpm, for example, it can be 1500 rpm, 1600 rpm, 1700 rpm, 1800 rpm, 1900 rpm or 2000 rpm, etc.

[0075] Preferably, the dispersing and mixing time is 30-40 min, for example, it can be 30 min, 31 min, 32 min, 33 min, 34 min, 35 min, 36 min, 37 min, 38 min, 39 min or 40 min, etc.

[0076] Preferably, the temperature for the drying is 60-70℃, for example, it can be 60℃, 61℃, 62℃, 63℃, 64℃, 65℃, 66℃, 67℃, 68℃, 69℃ or 70℃, etc.

[0077] Preferably, the way for the drying comprises vacuum drying.

[0078] Preferably, the vacuum degree for the vacuum drying is -0.08 MPa~ -0.09 MPa, for example, it can be -0.08 MPa, -0.082 MPa, -0.084 MPa, -0.086 MPa, -0.088 MPa or -0.09 MPa, etc.

[0079] Preferably, the sieving comprises sieving the modified nano-alumina crude product obtained after drying through a 100-mesh sieve.

[0080] Preferably, the water contact angle of the modified nano-alumina is ≥110°, for example, it can be 110°, 112°, 114°, 116°, 118°, 120°, 122°, 124°, 126°, 128° or 130°, etc.

[0081] Preferably, the pretreatment of the micron boron nitride comprises drying treatment of the micron boron nitride.

[0082] Preferably, the pretreatment of the reinforcing aid comprises drying treatment of the reinforcing aid.

[0083] Preferably, before the addition of the temperature-sensitive phase change microcapsule, the preliminary premix further comprises a grinding step.

[0084] In the present application, the grinding step can thoroughly break the filler agglomerates (especially nano-alumina), thereby forming a continuous heat-conducting network (co-constructed by alumina and boron nitride) while ensuring the insulation of the system (without the introduction of conductive impurities), and thus better realizing the "heat-conducting insulation" performance.

[0085] Preferably, the number of grinding is 3-5 times, for example, it can be 3 times, 4 times or 5 times.

[0086] In the present application, the temperature-sensitive phase change microcapsule is added after grinding, which can well ensure the uniform dispersion of each component in the base material without damaging the microcapsule structure (retaining the phase change heat storage and elastic buffer function), thereby improving the impact resistance of the rubber through the "elastic shell buffer + paraffin core phase change energy absorption" of the microcapsule; at the same time, the catalyst is added at the end, which can well promote the crosslinking and curing of the silicone rubber, realizing the "hardening" of the rubber (improving the hardness and mechanical strength), and at the same time, it is beneficial to avoid premature curing (ensuring the subsequent directional process time).

[0087] Preferably, the temperature-sensitive phase change microcapsules further comprise a pretreatment step before being added.

[0088] Preferably, the pretreatment of the temperature-sensitive phase change microcapsules comprises drying the temperature-sensitive phase change microcapsules after being passed through a 100-mesh sieve at 35-45℃ (for example, it can be 35℃, 38℃, 40℃, 42℃ or 45℃, etc.) for 25-35 min (for example, it can be 25 min, 28 min, 30 min, 32 min or 35 min, etc.) to make the water content ≤0.5%, thereby avoiding the generation of bubbles during the solidification process.

[0089] Preferably, the pretreatment of the catalyst comprises mixing the catalyst with ethanol at a mass ratio of 1:(15-20) (for example, it can be 1:15, 1:16, 1:17, 1:18, 1:19 or 1:20, etc.) to obtain a catalyst dispersion liquid, and the catalyst is added in the form of a dispersion liquid, which can avoid the problem of hardness difference caused by uneven local solidification.

[0090] Specifically, the preparation method of the heat-conducting, insulating and impact-resistant hardened rubber comprises the following steps:

[0091] The silicone rubber matrix, the filler, the reinforcing aid, the temperature-sensitive phase change microcapsules and the optional catalyst are pretreated respectively;

[0092] The pretreated filler, the pretreated reinforcing aid, the silane coupling agent are added into the pretreated silicone rubber matrix, and the mixture is uniformly mixed at 100-200 rpm to obtain a preliminary premix, and after grinding, the temperature-sensitive phase change microcapsules and the optional catalyst are added to obtain the heat-conducting, insulating and impact-resistant hardened rubber.

[0093] In a third aspect, the present application provides a potting method for a motor controller, which comprises using the heat-conducting, insulating and impact-resistant hardened rubber of the first aspect for potting.

[0094] Preferably, the potting method for the motor controller comprises the following steps:

[0095] (1) Pretreatment of the base material;

[0096] (2) Vacuum potting and curing using the heat-conducting, insulating and impact-resistant hardened rubber to obtain a potted layer.

[0097] Preferably, the pretreatment of step (1) comprises pretreatment of the housing and pretreatment of the printed circuit board (PCB).

[0098] By pretreating the housing (aluminum alloy) and the printed circuit board of the motor controller, the combination with the glue is improved by using the "physical embedding + chemical bonding" method, thereby avoiding delamination during impact.

[0099] Preferably, the shell pre-treatment comprises shell roughening, plasma activation and primer coating.

[0100] Preferably, the method of shell roughening comprises sand blasting roughening.

[0101] Preferably, the roughness (Ra) of the shell after roughening is 3.2-4.8 μm, for example, it can be 3.2 μm, 3.4 μm, 3.6 μm, 3.8 μm, 4 μm, 4.2 μm, 4.4 μm, 4.6 μm or 4.8 μm, etc.

[0102] The present application can effectively improve the surface energy of the shell after plasma activation.

[0103] It should be noted that the plasma treatment in the present application is a conventional method in the art, which is not particularly limited here, and exemplary methods include but are not limited to argon atmosphere, 40-60 W (for example, it can be 40 W, 42 W, 45 W, 48 W, 50 W, 52 W, 55 W, 58 W or 60 W, etc.) power plasma bombardment on the surface of the shell for 20-40 s (for example, it can be 20 s, 22 s, 25 s, 28 s, 30 s, 32 s, 35 s, 38 s or 40 s, etc.).

[0104] Preferably, the primer coating comprises silicone primer coating.

[0105] Preferably, the thickness of the primer coating is 50-100 μm, for example, it can be 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm or 100 μm, etc.

[0106] Preferably, the circuit board element pre-treatment comprises cleaning and primer coating of coupling agent.

[0107] It should be noted that the method of cleaning in the present application is not particularly limited, and the commonly used methods in the art are applicable, and exemplary methods include but are not limited to the method of ultrasonic treatment with anhydrous ethanol.

[0108] Preferably, the primer coating of coupling agent comprises spraying a coupling agent solution on the circuit board and drying.

[0109] Preferably, the coupling agent solution is obtained by mixing silane coupling agent and ethanol in a mass ratio of 1:(10-20) (for example, it can be 1:10, 1:12, 1:15, 1:18 or 1:20, etc.).

[0110] The coupling agent primer coating step can improve the grafting density of the colloid and the circuit board, thereby effectively improving the interface chemical bond density, and further increasing the interface adhesion and reducing the interface failure risk.

[0111] Preferably, before the vacuum potting in step (2), the heat-conducting insulating impact-hardening rubber is subjected to vacuum degassing treatment.

[0112] Preferably, the vacuum degree of the vacuum degassing is -0.1 MPa~ -0.07 MPa, for example, -0.1 MPa, -0.095 MPa, -0.09 MPa, -0.085 MPa, -0.08 MPa, -0.075 MPa or -0.07 MPa, etc.

[0113] Preferably, the vacuum degassing time is 10-15 min, for example, 10 min, 11 min, 12 min, 13 min, 14 min or 15 min, etc.

[0114] Preferably, the vacuum potting in step (2) includes step-by-step potting and magnetic field shaping.

[0115] Preferably, the step-by-step potting includes first potting the gaps between the circuit board components, and then potting the entire shell.

[0116] Preferably, the pressure of the vacuum potting in step (2) is -0.1 MPa~ -0.07 MPa (for example, -0.1 MPa, -0.095 MPa, -0.09 MPa, -0.085 MPa, -0.08 MPa, -0.075 MPa or -0.07 MPa, etc.), and the flow rate is 50-100 mL / min (for example, 50 mL / min, 60 mL / min, 70 mL / min, 80 mL / min, 90 mL / min or 100 mL / min, etc.).

[0117] Preferably, the magnetic field shaping in step (2) includes keeping the potting in a magnetic field with a strength of 0.4-0.6 T (0.4 T, 0.42 T, 0.45 T, 0.48 T, 0.5 T, 0.52 T, 0.55 T, 0.58 T or 0.6 T, etc.) for 25-35 min (25 min, 26 min, 27 min, 28 min, 29 min, 30 min, 31 min, 32 min, 33 min, 34 min or 35 min, etc.). Too high magnetic field strength will cause excessive stacking of boron nitride, which will block heat conduction; too low magnetic field strength will result in poor orientation effect.

[0118] Preferably, the curing in step (2) is three-stage curing.

[0119] Preferably, the three-stage curing comprises low-temperature flow leveling curing, medium-temperature deep curing and normal-temperature curing.

[0120] Preferably, the temperature of the low-temperature flow leveling curing is 55-65℃, for example, can be 55℃, 58℃, 60℃, 62℃ or 65℃, etc.

[0121] Preferably, the time of the low-temperature flow leveling curing is 2-4 h, for example, can be 2 h, 2.2 h, 2.5 h, 2.8 h, 3 h, 3.2 h, 3.5 h, 3.8 h or 4 h, etc.

[0122] Preferably, the temperature of the medium-temperature deep curing is 95-105℃, for example, can be 95℃, 98℃, 100℃, 102℃ or 105℃, etc.

[0123] Preferably, the time of the low-temperature flow leveling curing is 4-6 h, for example, can be 4 h, 4.2 h, 4.5 h, 4.8 h, 5 h, 5.2 h, 5.5 h, 5.8 h or 6 h, etc.

[0124] Preferably, the temperature of the normal-temperature curing is 20-30℃, for example, can be 20℃, 22℃, 24℃, 26℃, 28℃ or 30℃, etc.

[0125] Preferably, the time of the normal-temperature curing is 20-30 h, for example, can be 20 h, 22 h, 24 h, 26 h, 28 h or 30 h, etc.

[0126] In particular, the potting method of the motor controller comprises the following steps:

[0127] (1) Pretreatment of the base material: after the shell is sandblasted to a roughness of 3.2-4.8 μm, plasma activation and structure adhesive primer are performed; after the circuit board element is cleaned, coupling agent primer is applied;

[0128] (2) After the heat-conducting insulating impact-resistant hardened rubber is defoamed at -0.1 MPa~-0.07 MPa for 10-15 min, the circuit board element gap is first potted at a pressure of -0.1 MPa~-0.07 MPa and a flow rate of 50-100 mL / min, and then the shell as a whole is potted, after the potting is completed, it is kept in a magnetic field with a strength of 0.5 T for 30 min, and finally three-stage curing is performed, wherein the low-temperature flow leveling curing is 55-65℃ for 2-4 h, the medium-temperature deep curing is 95-105℃ for 4-6 h, and the normal-temperature curing is 20-30℃ for 20-30 h, the potting is completed, and a workpiece with a potting layer is obtained.

[0129] Compared with the prior art, the present application has at least the following beneficial effects:

[0130] (1) The heat-conducting, insulating and impact-hardening rubber of the present application uses multi-scale fillers (nano-micron filler combination), reinforcing aids, temperature-sensitive phase change microcapsules and a silicone rubber matrix, and realizes impact hardening through a strain rate sensitive shear thickening mechanism, so that the heat-conducting, insulating and impact-hardening rubber has the non-Newtonian fluid characteristics of low viscosity flow in normal state and rapid hardening upon impact. When it is applied in a potting process, it can effectively solve the technical problems of thermal failure, mechanical damage and insulation failure of high-power-density electronic devices in vibration, impact and high-temperature, high-voltage environments, and is suitable for scenes with high reliability requirements such as vehicle-mounted, aerospace, unmanned aerial vehicle industrial automation, etc.

[0131] (2) The heat-conducting, insulating and impact-hardening rubber provided by the present application has excellent comprehensive performance such as high-efficiency heat conduction, high insulation, rapid impact hardening and reliable interface bonding. The potting layer obtained by using the same has a thermal conductivity of 1.8-2.4 W / (m·K), a volume resistance of 3×10 12 -5×10 14 Ω·cm, an impact response time of ≤8 ms and an impact energy absorption rate of >71%. DETAILED DESCRIPTION

[0132] In order to facilitate the understanding of the present application, the present application is illustrated as follows. It should be understood by those skilled in the art that the examples are only to help understand the present application and should not be regarded as a specific limitation on the present application.

[0133] The reagents and raw materials used in the following examples and comparative examples are all commercially available products unless otherwise specified. Some raw material information is as follows:

[0134] High-vinyl silicone rubber (vinyl content 0.3 mol%): purchased from Shin-Etsu Chemical KE-77;

[0135] Platinum catalyst: purchased from Guangzhou Siyou New Materials PT-5000SW;

[0136] Temperature-sensitive phase change microcapsules: paraffin-elastomer microcapsules, purchased from Ningbo Panyi New Materials MOFPoly PCM-45;

[0137] SiO2-coated SiC: SiO2@SiC, average particle size 2 μm, thickness of SiO2 coating layer 50-80 nm;

[0138] Al2O3-SiO2-coated SiC: SiO2@Al2O3@SiC, average particle size 2 μm, thickness of Al2O3 inner layer 30-50 nm, thickness of SiO2 outer layer 30-80 nm, total coating thickness 60-130 nm.

[0139] Example 1

[0140] The present example provides a heat-conducting insulating impact-hardened rubber, raw materials for preparing the heat-conducting insulating impact-hardened rubber comprising components in the following weight proportions:

[0141] high-vinyl silicone rubber 100 parts;

[0142] nano-alumina (average particle size 50 nm) 15 parts;

[0143] micron boron nitride (average particle size 2 μm) 15 parts;

[0144] micron boron nitride (average particle size 8 μm) 10 parts;

[0145] SiO2@SiC 6 parts;

[0146] KH-560 3 parts;

[0147] temperature-sensitive phase change microcapsules 1 part;

[0148] platinum gold catalyst 0.03 parts.

[0149] Example 2

[0150] The present example provides a heat-conducting insulating impact-hardened rubber, raw materials for preparing the heat-conducting insulating impact-hardened rubber comprising components in the following weight proportions:

[0151] high-vinyl silicone rubber 100 parts;

[0152] nano-alumina (average particle size 30 nm) 15 parts;

[0153] micron boron nitride (average particle size 2 μm) 15 parts;

[0154] micron boron nitride (average particle size 8 μm) 10 parts;

[0155] SiO2@Al2O3@SiC 6 parts;

[0156] KH-560 2.5 parts;

[0157] temperature-sensitive phase change microcapsules 1 part;

[0158] platinum gold catalyst 0.03 parts.

[0159] Example 3

[0160] The present example provides a heat-conducting insulating impact-hardened rubber, raw materials for preparing the heat-conducting insulating impact-hardened rubber comprising components in the following weight proportions:

[0161] high-vinyl silicone rubber 100 parts;

[0162] nano-alumina (average particle size 30 nm) 15 parts;

[0163] micron-boron nitride (average particle size 2 μm) 15 parts;

[0164] micron-boron nitride (average particle size 8 μm) 10 parts;

[0165] micron-alumina (average particle size 5 μm) 6 parts;

[0166] KH-560 3.5 parts;

[0167] temperature-sensitive phase-change microcapsule 1 part;

[0168] platinum-gold catalyst 0.03 parts.

[0169] Example 4

[0170] The present example provides a heat-conducting insulating impact-hardened rubber, raw materials for preparing the heat-conducting insulating impact-hardened rubber comprising the following components in parts by weight:

[0171] high-vinyl silicone rubber 100 parts;

[0172] nano-alumina (average particle size 50 nm) 20 parts;

[0173] micron-boron nitride (average particle size 2 μm) 10 parts;

[0174] micron-boron nitride (average particle size 8 μm) 5 parts;

[0175] micron-alumina (average particle size 5 μm) 5 parts;

[0176] KH-560 1.5 parts;

[0177] temperature-sensitive phase-change microcapsule 0.5 parts;

[0178] platinum-gold catalyst 0.05 parts.

[0179] Example 5

[0180] The present example provides a heat-conducting insulating impact-hardened rubber, raw materials for preparing the heat-conducting insulating impact-hardened rubber comprising the following components in parts by weight:

[0181] high-vinyl silicone rubber 100 parts;

[0182] nano-alumina (average particle size 50 nm) 10 parts;

[0183] Micron boron nitride (average particle size 2 μm) 20 parts;

[0184] Micron boron nitride (average particle size 8 μm) 10 parts;

[0185] SiO2@Al2O3@SiC 2 parts;

[0186] Micron alumina (average particle size 5 μm) 3 parts;

[0187] KH-560 2 parts;

[0188] Temperature-sensitive phase change microcapsule 2 parts;

[0189] Platinum gold catalyst 0.01 part.

[0190] Example 6

[0191] The present example provides a heat-conducting insulating impact-hardened rubber, which is only different from example 1 in that micron boron nitride (average particle size 8 μm) is not added, and the reduced weight fraction is distributed to micron boron nitride (average particle size 2 μm), and other raw materials and additive amounts are the same as in example 1.

[0192] Example 7

[0193] The present example provides a heat-conducting insulating impact-hardened rubber, which is only different from example 1 in that micron boron nitride (average particle size 2 μm) is not added, and the reduced weight fraction is distributed to micron boron nitride (average particle size 8 μm), and other raw materials and additive amounts are the same as in example 1.

[0194] Example 8

[0195] The present example provides a heat-conducting insulating impact-hardened rubber, which is only different from example 1 in that the mass ratio of micron boron nitride (average particle size 8 μm) and micron boron nitride (average particle size 2 μm) is adjusted from 1.5:1 to 1:1, i.e. the weight fraction of micron boron nitride (average particle size 2 μm) is 12.5 parts, and the weight fraction of micron boron nitride (average particle size 8 μm) is 12.5 parts, and other raw materials and additive amounts are the same as in example 1.

[0196] Example 9

[0197] The embodiment provides a heat-conducting insulating impact-resistant hardened rubber, which is only different from the embodiment 1 in that the mass ratio of micron boron nitride (average particle size 8 microns) and micron boron nitride (average particle size 2 microns) is adjusted from 1.5:1 to 2:1, i.e. the weight fraction of the micron boron nitride (average particle size 2 microns) is 16.7 parts, the weight fraction of the micron boron nitride (average particle size 8 microns) is 8.3 parts, and other raw materials and additive amounts are the same as those in the embodiment 1.

[0198] Embodiment 10

[0199] The embodiment provides a heat-conducting insulating impact-resistant hardened rubber, which is only different from the embodiment 1 in that the mass ratio of micron boron nitride (average particle size 8 microns) and micron boron nitride (average particle size 2 microns) is adjusted from 1.5:1 to 2.5:1, i.e. the weight fraction of the micron boron nitride (average particle size 2 microns) is 17.9 parts, the weight fraction of the micron boron nitride (average particle size 8 microns) is 7.1 parts, and other raw materials and additive amounts are the same as those in the embodiment 1.

[0200] Embodiment 11

[0201] The embodiment provides a heat-conducting insulating impact-resistant hardened rubber, which is only different from the embodiment 1 in that the mass ratio of micron boron nitride (average particle size 8 microns) and micron boron nitride (average particle size 2 microns) is adjusted from 1.5:1 to 3:1, i.e. the weight fraction of the micron boron nitride (average particle size 2 microns) is 18.8 parts, the weight fraction of the micron boron nitride (average particle size 8 microns) is 6.2 parts, and other raw materials and additive amounts are the same as those in the embodiment 1.

[0202] Comparative example 1

[0203] The embodiment provides a heat-conducting insulating impact-resistant hardened rubber, which is only different from the embodiment 1 in that the mass ratio of micron boron nitride (average particle size 8 microns) and micron boron nitride (average particle size 2 microns) is adjusted from 1.5:1 to 3:1, i.e. the weight fraction of the micron boron nitride (average particle size 2 microns) is 18.8 parts, the weight fraction of the micron boron nitride (average particle size 8 microns) is 6.2 parts, and other raw materials and additive amounts are the same as those in the embodiment 1.

[0204] The embodiment provides a heat-conducting insulating impact-resistant hardened rubber, which is only different from the embodiment 1 in that the mass ratio of micron boron nitride (average particle size 8 microns) and micron boron nitride (average particle size 2 microns) is adjusted from 1.5:1 to 3:1, i.e. the weight fraction of the micron boron nitride (average particle size 2 microns) is 18.8 parts, the weight fraction of the micron boron nitride (average particle size 8 microns) is 6.2 parts, and other raw materials and additive amounts are the same as those in the embodiment 1.

[0205] The pre-treatment method comprises the following steps:

[0206] The high-vinyl silicone rubber is placed in an open type rubber mixing mill (roller temperature 55 DEG C, roller distance 1 mm) and plasticated for 6 min.

[0207] The modified nano-alumina was obtained by mixing nano-alumina with KH-560 solution at a solid-liquid ratio of 1:4 under stirring at 1800 rpm for 35 min, drying at-0.085 MPa and 65°C for 2.5 h, cooling to 25°C, and passing through a 100-mesh sieve, wherein the KH-560 solution was prepared by mixing silane coupling agent and ethanol at a mass ratio of 1:32.

[0208] The temperature-sensitive phase change microcapsules were dried at 40°C for 30 min after passing through a 100-mesh sieve.

[0209] The micron-sized boron nitride was dried in a 80°C air-drying oven for 1 h.

[0210] The micron-sized alumina was dried in a 80°C air-drying oven for 1 h.

[0211] The SiO2-coated SiC was dried in a 80°C air-drying oven for 1 h.

[0212] The Al2O3-SiO2-coated SiC was dried in a 80°C air-drying oven for 1 h.

[0213] The platinum-gold catalyst dispersion liquid was obtained by mixing platinum-gold catalyst and ethanol at a mass ratio of 1:16.7.

[0214] The preparation method comprises the following steps:

[0215] After plasticizing, the high-vinyl silicone rubber was mixed with the pretreated reinforcing aid (at least one of SiO2@SiC, SiO2@Al2O3@SiC, or micron-sized alumina), micron-sized boron nitride (added in two portions, 2 μm first and then 8 μm, with an interval of 5 min), KH-560, at 150 rpm, and stirred for 12 min after each addition of a raw material. Finally, the modified nano-alumina was added in three portions, with an interval of 8 min between each portion, and the stirring speed was increased to 190 rpm. After uniform mixing for 28 min, the preliminary premix was obtained. After being ground by a three-roll grinder for three times until no obvious particles were observed, the pretreated temperature-sensitive phase change microcapsules were added in two portions, with an interval of 8 min between each portion, and stirred for 8 min after each addition. Finally, the platinum-gold catalyst dispersion liquid was added dropwise, and stirred for 20 min to obtain the heat-conducting, insulating, and impact-resistant hardened rubber.

[0216] Comparative Example 2

[0217] This comparative example provides a rubber material (Wacker SilGel 612 two-component silicone gel).

[0218] Application Example 1

[0219] This application example provides a potting method for a motor controller, which comprises the following steps:

[0220] (1) Pretreatment of the substrate: after sandblasting the shell with 80 mesh alumina to a roughness of 4 μm, the shell surface was subjected to plasma bombardment under an argon atmosphere at 50 W for 30 s, and finally coated with silicone structural adhesive with a thickness of 80 μm; the circuit board element was ultrasonically cleaned in anhydrous ethanol for 5 min, then sprayed with a dilute solution of KH-560 in ethanol (mass ratio of KH-560 to ethanol 1:10), and dried at 80°C for 10 min;

[0221] (2) After the heat-conducting insulating impact-hardening rubber (Example 1) was debubbled at -0.095 MPa for 12 min, the circuit board element gap was first filled at a pressure of -0.1 MPa and a flow rate of 80 mL / min, and then the entire shell was filled, after which the workpiece was kept in a magnetic field with a strength of 0.5 T for 30 min, and finally cured in three stages, with low-temperature flow leveling and curing at 60°C for 3 h, medium-temperature deep curing at 100°C for 5 h, and room-temperature maturation at 25°C for 24 h, to complete the filling and obtain a workpiece with a filled layer.

[0222] Application Examples 2-11 and Comparative Application Examples 1-2

[0223] Application Examples 2-11 and Comparative Application Examples 1-2 each provide a method for filling a motor controller, which differs from Application Example 1 only in that the heat-conducting insulating impact-hardening rubber (Example 1) in step (2) of Application Example 1 is replaced by the heat-conducting insulating impact-hardening rubber (Examples 2-11, Comparative Examples 1-2), respectively, and the other method steps are the same as in Application Example 1.

[0224] The filled layer products obtained in Application Examples 1-11 and Comparative Application Examples 1-2 were subjected to performance testing, and the test methods / standards were as follows:

[0225] (1) Thermal conductivity: tested in accordance with GB / T 11205;

[0226] (2) Volume resistivity: tested in accordance with GB / T 1410;

[0227] (3) Impact response time: tested in accordance with ASTM D3763;

[0228] (4) Impact energy absorption rate: tested in accordance with GB / T 1843.

[0229] The test results are shown in Table 1.

[0230] Table 1

[0231]

[0232] From the test results, it can be seen that:

[0233] (1) As can be seen from Application Examples 1 to 11, by adopting the multi-scale filler (nano-micron filler compound), the reinforcing aid, the temperature-sensitive phase change microcapsule and the silicone rubber matrix, the obtained heat-conducting and insulating impact-hardened rubber can realize the comprehensive performance improvement of efficient heat conduction, high insulation, rapid impact hardening and reliable interface bonding, and when applied to the potting process, the measured thermal conductivity is 1.8-2.4 W / (m·K), the volume resistance is 3×10 12 -5×10 14 Ω·cm, the impact response time is 4.9-7.6 ms, and the impact energy absorption rate is 71-94%.

[0234] (2) As can be seen from the comparison of Application Example 2 and Application Examples 6 and 7, the heat-conducting and insulating impact-hardened rubber obtained by using only a single particle size of micron boron nitride in Application Examples 6 and 7 has a lower thermal conductivity when applied to the potting process, indicating that the compounding of 2 μm micron boron nitride and 8 μm micron boron nitride in the present application can play a synergistic effect, thereby improving the heat conduction performance of the obtained heat-conducting and insulating impact-hardened rubber. Further, as can be seen from the comparison of Application Example 2 and Application Examples 8-11, the mass ratio of 2 μm micron boron nitride and 8 μm micron boron nitride is lower in Application Example 8 and higher in Application Example 11, and the heat-conducting and insulating impact-hardened rubber obtained by the two has a lower thermal conductivity when applied to the potting process, further indicating that by further optimizing the mass ratio of 2 μm micron boron nitride and 8 μm micron boron nitride, the heat conduction performance of the obtained heat-conducting and insulating impact-hardened rubber can be significantly improved.

[0235] (3) As can be seen from the comparison of Application Example 2 and Comparative Application Example 1, the heat-conducting and insulating impact-hardened rubber obtained by not containing the temperature-sensitive phase change microcapsule in Comparative Application Example 1 has a impact response time of 9.1 ms when applied to the potting process, which is higher than 8 ms, and the impact energy absorption rate is only 60.7%, which is much lower than 70%, indicating that the addition of the specific temperature-sensitive phase change microcapsule in the present application can significantly improve the impact resistance of the obtained heat-conducting and insulating impact-hardened rubber.

[0236] (4) By comparing application examples 1-11 with comparative application example 2, it can be seen that the heat-conducting and impact-resistant hardening rubber obtained by the comparative application example 2 is applied to the potting process, and the measured thermal conductivity is only 0.4 W / (m·K), the heat conduction performance is poor, the impact response time is as high as 18.2 ms, and the impact energy absorption rate is only 32.4%, the rapid impact hardening performance is poor, which shows that the heat-conducting and impact-resistant hardening rubber provided by the present application has good insulation, and through the multi-scale filler design and interface modification technology, the heat conduction and impact resistance are improved in all dimensions.

[0237] Applicants declare that the above description is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and those skilled in the art should understand that any changes or replacements within the technical scope disclosed by the present application can be easily thought of by any person skilled in the art, and all fall within the protection scope and disclosure scope of the present application.

Claims

1. A heat conductive, insulating, impact resistant, vulcanized rubber, characterized in that, The preparation raw materials of the heat-conducting, insulating, impact-resistant and hardened rubber include a silicone rubber matrix, fillers, a reinforcing aid, a silane coupling agent and temperature-sensitive phase change microcapsules; the fillers include nano-aluminum oxide and micron-boron nitride.

2. The thermally conductive, insulating, impact hardened rubber of claim 1, wherein, The preparation raw materials of the heat-conducting, insulating, impact-resistant and hardened rubber include the following components in weight fractions: 100 parts of silicone rubber matrix; 10-20 parts of nano-aluminum oxide; 15-30 parts of micron-boron nitride; 5-10 parts of reinforcing aid; 1.5-3.5 parts of silane coupling agent; 0.5-2 parts of temperature-sensitive phase change microcapsules.

3. The thermally conductive, electrically insulating, impact-resistant vulcanizate of claim 1 or 2, wherein, The micron-boron nitride includes at least one micron-boron nitride with an average particle size of 1-10 μm; Preferably, the micron-boron nitride is selected from a combination of low-particle-size micron-boron nitride and high-particle-size micron-boron nitride; Preferably, the low-particle-size micron-boron nitride has an average particle size of 1-3 μm; Preferably, the high-particle-size micron-boron nitride has an average particle size of 7-9 μm; Preferably, the mass ratio of the low-particle-size micron-boron nitride to the high-particle-size micron-boron nitride is (1.5-2.5):

1.

4. The thermally conductive, electrically insulative, impact-resistant, vulcanized rubber of any one of claims 1-3, wherein, The reinforcing aid includes micron-aluminum oxide and / or silicon carbide with a core-shell structure; Preferably, the micron-aluminum oxide has an average particle size of 3-8 μm; Preferably, the silicon carbide with a core-shell structure has an average particle size of 1-3 μm; Preferably, the silicon carbide with a core-shell structure includes a silicon carbide core and a cladding layer; Preferably, the cladding layer has a thickness of 50-130 nm.

5. The thermally conductive, insulating, impact hardened rubber of claim 4, wherein, The cladding layer is a silica cladding layer or an alumina-silica composite cladding layer; Preferably, when the cladding layer is a silica cladding layer, the mass percentage of the silicon carbide core is ≥90% based on 100% of the mass percentage of the silicon carbide with a core-shell structure; Preferably, the silica cladding layer has a thickness of 50-80 nm; Preferably, the alumina-silica composite cladding layer includes an alumina inner layer and a silica outer layer; Preferably, the alumina inner layer of the alumina-silica composite cladding layer has a thickness of 30-50 nm; Preferably, the silica outer layer of the alumina-silica composite cladding layer has a thickness of 30-80 nm.

6. The thermally conductive, electrically insulative, impact-resistant vulcanizate of any of claims 1-5, wherein, The nano-aluminum oxide has an average particle size of 30-100 nm; Preferably, the nano-aluminum oxide has a surface hydroxyl coverage rate of ≥95%.

7. The thermally conductive, electrically insulative, impact-resistant vulcanizate of any of claims 1-6, wherein, The silicone rubber matrix includes a vinyl silicone rubber matrix; Preferably, the vinyl silicone rubber matrix has a vinyl content of ≥0.2 mol%; Preferably, the temperature-sensitive phase change microcapsules include a core material and a shell material; Preferably, the core material of the temperature-sensitive phase change microcapsules includes paraffin and / or octadecane; Preferably, the shell material of the temperature-sensitive phase change microcapsules includes an elastomer; Preferably, the preparation raw materials of the heat-conducting, insulating, impact-resistant and hardened rubber further include a catalyst; Preferably, the preparation raw materials of the heat-conducting, insulating, impact-resistant and hardened rubber include 0.01-0.05 parts of catalyst.

8. A process for the preparation of the heat conductive, electrically insulating, impact- resistant vulcanizate according to any one of claims 1 to 7, characterized in that, The preparation method includes the following steps: The preliminary premix is obtained by mixing the silicone rubber matrix, the filler, the reinforcing aid and the silane coupling agent, and then the temperature-sensitive phase change microcapsules and the optional catalyst are added to obtain the heat-conducting, insulating and impact-resistant hardened rubber.

9. A method of potting a motor controller, characterized by, The potting method comprises using the heat-conducting, insulating and impact-resistant hardened rubber according to any one of claims 1-7 for potting.

10. The method of potting according to claim 9, wherein, The potting method comprises the following steps: (1) pretreatment of the base material; (2) vacuum potting and curing using the heat-conducting, insulating and impact-resistant hardened rubber to complete the potting and obtain a workpiece with a potting layer; Preferably, the pretreatment in step (1) comprises shell pretreatment and circuit board element pretreatment. Preferably, the vacuum potting in step (2) further comprises vacuum deaeration treatment of the heat-conducting, insulating and impact-resistant hardened rubber before the vacuum potting. Preferably, the vacuum potting in step (2) comprises step-by-step potting and magnetic field shaping.

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