Organic silicon heat-conducting pouring sealant and preparation method thereof

Abstract

The invention belongs to the technical field of heat-conducting pouring sealants, and particularly provides an organic silicon heat-conducting pouring sealant and a preparation method thereof. The preparation method of the organosilicone heat-conducting pouring sealant comprises the following steps: 1) uniformly mixing an organosilicone component A, crystalline flake graphite, aluminum oxide, boron nitride and layered transition metal oxide to obtain a first sealant material; the preparation method comprises 1) preparing a first sizing material, 2) uniformly mixing an organic silica gel component B, a composite fiber and a compatilizer to obtain a second sizing material, and 3) uniformly mixing the first sizing material and a second crosslinking agent to obtain the organic silica gel heat-conducting pouring sealant, The organic silica gel heat-conducting pouring sealant has the advantages of good heat-conducting property, high strength and high toughness.

Description

Technical Field

[0001] The present invention relates to the field of potting compound technology, and in particular to a silicone thermally conductive potting compound and a preparation method thereof. Background Art

[0002] As the microelectronics industry experiences a period of rapid growth, electronic products are becoming increasingly versatile, devices are becoming increasingly compact, circuit integration is increasing, and electronic components are being packed ever more densely within the unit volume of integrated circuits. As the number and variety of electronic components on circuit boards increase, the spacing between them is shrinking, and the requirements for heat dissipation are becoming increasingly stringent. Failure to employ appropriate heat dissipation technologies can significantly increase component wear, shortening their lifespans, increasing safety risks, and increasing maintenance costs.

[0003] Silicone potting materials are resistant to high and low temperatures, maintaining stable performance at temperatures between -60°C and 200°C. They also offer excellent weather resistance, chemical resistance, electrical insulation, and rapid high-temperature curing. Therefore, they hold broad research potential and application prospects in areas such as electronic component packaging and protection. However, silicone potting materials have a low thermal conductivity of approximately 0.2 W / (m·K), which cannot meet the heat dissipation requirements of real-world production and life. This can severely impact the lifespan of electronic equipment and increase safety risks, necessitating improvements in thermal conductivity and other performance characteristics.

[0004] Adding various functional fillers to potting compounds can effectively enhance their performance. These fillers are cost-effective and offer stable performance, making them widely used in research to improve the thermal conductivity of potting compounds. Commonly used thermally conductive fillers include carbon nanotubes, carbon fibers, aluminum oxide, boron nitride, and silicon carbide. These fillers can significantly enhance the thermal conductivity of silicone rubber. However, at a certain filler loading, the mechanical properties, anti-settling properties, and storage stability of the potting compound deteriorate.

[0005] To address this, technicians have modified thermally conductive filler particles with silane coupling agents to improve the potting compound's anti-settling properties. Alternatively, nano-calcium carbonate, hollow glass microspheres, and other materials have been combined with thermally conductive fillers to improve the potting compound's storage stability and strength. However, these methods still cannot meet the potting requirements of high-performance electronic devices. Summary of the Invention

[0006] In view of the above problems, in order to further improve the performance of the organosilicon potting compound, the present application provides an organosilicon thermal conductive potting compound and a preparation method thereof.

[0007] This application first provides a method for preparing a silicone thermally conductive potting compound, comprising the following steps: 1) Mixing the organic silica gel component A, flake graphite, aluminum oxide, boron nitride, and layered transition metal oxide to obtain a first rubber compound; 2) uniformly mixing the organic silica gel component B, the composite fiber, and the compatibilizer to obtain a second rubber compound; the composite fiber is made of polyacrylonitrile fiber and zirconium-based fiber; 3) Mix the first rubber material and the second cross-linking material evenly.

[0008] Furthermore, the preparation method of the layered transition metal oxide comprises the following steps: S1: dissolving aluminum nitrate and cobalt nitrate in deionized water and stirring thoroughly to obtain precursor solution A; adding melamine and manganese nitrate to the tetrabutylphosphine hydroxide solution and mixing thoroughly to obtain precursor solution B; S2: Precursor solution A and precursor solution B are mixed evenly, the pH is adjusted to be weakly alkaline, and after aging treatment, the temperature is raised to 500-600° C. at a heating rate of 5-7.5° C. / min and sintered, and layered transition metal oxides are obtained after grinding.

[0009] Furthermore, in step S1, the molar ratio of aluminum nitrate to cobalt nitrate in the precursor solution A is (2-3.5):1; And / or, in step S1, the mass ratio of melamine to manganese nitrate in the precursor solution B is 1:(0.03-0.05); And / or, in step S2, the volume ratio of precursor solution A to precursor solution B is (0.25-0.5):1.

[0010] Furthermore, the composite fiber is prepared by the following steps: A) Zirconium polyacetylacetonate is dissolved in methanol, and then ethyl orthosilicate is added and mixed uniformly to prepare a spinning solution 1; polyacrylonitrile is dissolved in N,N-dimethylformamide and heated to fully dissolve to prepare a spinning solution 2; B) The spinning solution 1 and the spinning solution 2 are conjugately electrospun to obtain hybrid fibers, and then the hybrid fibers are pretreated at a temperature of 200-280° C., then heated to 1100-1300° C., kept warm under an inert gas atmosphere, cooled, and pulverized to obtain composite fibers.

[0011] Furthermore, in step A), the molar ratio of zirconium polyacetylacetonate to tetraethyl orthosilicate in the spinning solution 1 is 1:(0.1-0.35); And / or, in step A), the mass percentage of polyacrylonitrile in the second spinning solution is 15-20%; And / or, in the step B), the flow rate ratio of the spinning solution 1 to the spinning solution 2 is 1:(0.65-0.8).

[0012] Furthermore, in step B), the hybrid fiber is further modified by the following steps: preparing a dopamine solution and immersing the hybrid fiber in the dopamine solution; transferring the immersed hybrid fiber to a metal oxide dispersion, continuing the immersion treatment, and then washing and drying.

[0013] Furthermore, the mass percentage of the dopamine solution is 10-15%.

[0014] Furthermore, during the impregnation process, L-hydroxyproline accounting for 5-8% of the mass of the dopamine solution is added; And / or, the metal oxide in the metal oxide dispersion is one or more of iron oxide, yttrium oxide, and copper oxide.

[0015] Furthermore, the metal oxide is composed of yttrium oxide and copper oxide in a mass ratio of (0.3-0.5):1.

[0016] The present application also provides a silicone thermally conductive potting compound, which is prepared using the above-mentioned preparation method.

[0017] Compared with the prior art, this application has the following beneficial effects: 1. This application adds layered transition metal oxides and composite fibers to the thermally conductive potting system to construct multi-scale toughening and anti-settling structures at the micro-nano scale and macro-scale, respectively, to regulate the arrangement and dispersion of weak bridging interfaces and thermally conductive filler particles inside the thermally conductive potting system, and to utilize the fracture energy dissipation, crack bridging, and interlayer slip mechanisms of layered transition metal oxides and composite fibers at multiple scales to improve the strength, toughness, and anti-settling properties of the thermally conductive potting system, while also improving the thermal conductivity to a certain extent.

[0018] 2. The layered transition metal oxides of this application can form a stacked structure within a thermally conductive potting compound system, leveraging the close contact between the layers to generate high interfacial bonding and strength. Furthermore, the introduction of composite fibers can further form a more macroscopic interpenetrating phase network structure based on the micro- and nano-scale layered structure, effectively promoting stress transfer, dispersing damage, and preventing cracking, thereby enhancing the strength and toughness of the thermally conductive potting compound. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a graph showing the thermal conductivity test data of the organic thermally conductive potting compound of Examples 1-3 and Control Groups 1-2 of the present application.

[0020] Figure 2 This is a graph showing the mechanical properties test data of the organic thermally conductive potting adhesive of Examples 1-3 and Control Groups 1-2 of the present application.

[0021] Figure 3This is the SEM image of the layered transition metal oxide of Example 3 of the present application.

[0022] Figure 4 This is the SEM image of the composite fiber of Example 3 of the present application. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0024] After extensive experimental research, this application provides a method for preparing a silicone thermally conductive potting compound, comprising the following steps: 1) Mixing the organic silica gel component A, flake graphite, aluminum oxide, boron nitride, and layered transition metal oxide to obtain a first rubber compound; 2) uniformly mixing the organic silica gel component B, the composite fiber, and the compatibilizer to obtain a second rubber compound; the composite fiber is made of polyacrylonitrile fiber and zirconium-based fiber; 3) Mix the first rubber material and the second cross-linking material evenly.

[0025] Furthermore, the preparation method of the layered transition metal oxide comprises the following steps: S1: dissolving aluminum nitrate and cobalt nitrate in deionized water and stirring thoroughly to obtain precursor solution A; adding melamine and manganese nitrate to the tetrabutylphosphine hydroxide solution and mixing thoroughly to obtain precursor solution B; S2: Precursor solution A and precursor solution B are mixed evenly, the pH is adjusted to be weakly alkaline, and after aging treatment, the temperature is raised to 500-600° C. at a heating rate of 5-7.5° C. / min and sintered, and layered transition metal oxides are obtained after grinding.

[0026] Furthermore, in step S1, the molar ratio of aluminum nitrate to cobalt nitrate in the precursor solution A is (2-3.5):1; And / or, in step S1, the mass ratio of melamine to manganese nitrate in the precursor solution B is 1:(0.03-0.05); And / or, in step S2, the volume ratio of precursor solution A to precursor solution B is (0.25-0.5):1.

[0027] In some specific embodiments, in step S1, the molar ratio of aluminum nitrate to cobalt nitrate in the precursor solution A can be (2-2.5):1, (2.5-3):1, (3-3.5):1. More preferably, the molar ratio of aluminum nitrate to cobalt nitrate in the precursor solution A can be 2:1, 2.2:1, 2.5:1, 2.8:1, 3:1, 3.2:1, 3.5:1. Under normal circumstances, when the molar ratio of aluminum nitrate to cobalt nitrate in the precursor solution A is 2.5:1, better experimental results can be obtained.

[0028] In some specific embodiments, in step S1, the mass ratio of melamine to manganese nitrate in the precursor solution B can be 1:0.03, 1:0.035, 1:0.04, 1:0.045, or 1:0.05. More preferably, under normal circumstances, the effect is better when the mass ratio of melamine to manganese nitrate in the precursor solution B is 1:0.05.

[0029] In some specific embodiments, in step S2, the volume ratio of precursor solution A to precursor solution B can be (0.25-0.3):1, (0.3-0.35):1, (0.35-0.4):1, (0.45-0.5):1. More preferably, the volume ratio of precursor solution A to precursor solution B can be 0.25:1, 0.28:1, 0.3:1, 0.35:1, 0.37:1, 0.4:1, 0.45:1, or 0.5:1. Generally, the effect is better when the volume ratio of precursor solution A to precursor solution B is 0.35:1.

[0030] Furthermore, the composite fiber is prepared by the following steps: A) Zirconium polyacetylacetonate is dissolved in methanol, and then ethyl orthosilicate is added and mixed uniformly to prepare a spinning solution 1; polyacrylonitrile is dissolved in N,N-dimethylformamide and heated to fully dissolve to prepare a spinning solution 2; B) The spinning solution 1 and the spinning solution 2 are conjugately electrospun to obtain hybrid fibers, and then the hybrid fibers are pretreated at a temperature of 200-280° C., then heated to 1100-1300° C., kept warm under an inert gas atmosphere, cooled, and pulverized to obtain composite fibers.

[0031] Furthermore, in step A), the molar ratio of zirconium polyacetylacetonate to tetraethyl orthosilicate in the spinning solution 1 is 1:(0.1-0.35); And / or, in step A), the mass percentage of polyacrylonitrile in the second spinning solution is 15-20%; And / or, in the step B), the flow rate ratio of the spinning solution 1 to the spinning solution 2 is 1:(0.65-0.8).

[0032] In certain specific embodiments, in step A), the molar ratio of zirconium polyacetylacetonate to tetraethyl orthosilicate in the spinning solution 1 can be 1:0.1, 1:0.15, 1:0.2, 1:0.25, 1:0.3, or 1:0.35. Generally, when the molar ratio of zirconium polyacetylacetonate to tetraethyl orthosilicate in the spinning solution 1 is 1:0.3, the experimental effect is better.

[0033] In certain specific embodiments, in step A), the mass percentage of polyacrylonitrile in the second spinning solution may be 15%, 15.5%, 16%, 17%, 17.5%, 18%, 18.5%, 19%, 19.5%, or 20%. More preferably, under normal circumstances, a mass percentage of polyacrylonitrile in the second spinning solution of 15.5% achieves better results.

[0034] In certain embodiments, in step B), the flow rate ratio of the first spinning solution to the second spinning solution can be 1:0.65, 1:0.7, 1:0.75, or 1:0.8. Generally, a flow rate ratio of 1:0.7 to 2 spinning solution is better.

[0035] More preferably, the relative molecular mass of polyacrylonitrile is 5.5×10 4 .

[0036] Furthermore, in step B), the hybrid fiber is further modified by the following steps: preparing a dopamine solution and immersing the hybrid fiber in the dopamine solution; transferring the immersed hybrid fiber to a metal oxide dispersion, continuing the immersion treatment, and then washing and drying.

[0037] Furthermore, the mass percentage of the dopamine solution is 10-15%.

[0038] Furthermore, during the impregnation process, L-hydroxyproline accounting for 5-8% of the mass of the dopamine solution is added; And / or, the metal oxide in the metal oxide dispersion is one or more of iron oxide, yttrium oxide, and copper oxide.

[0039] Furthermore, the metal oxide is composed of yttrium oxide and copper oxide in a mass ratio of (0.3-0.5):1.

[0040] Example 1 The preparation method of the organic silicon thermal conductive potting compound of this embodiment comprises the following steps: 1) 120 g of component A of organic silica gel (component A of Dow Corning SYLGARD 184), 20 g of flake graphite (325 mesh), 5 g of alumina (average particle size 100 μm), 5 g of boron nitride (average length 15 μm, average diameter 2 μm), and 5 g of layered transition metal oxide were mixed to obtain a first rubber compound; 2) 15 g of organic silica gel component B (component B of Dow Corning SYLGARD 184), 5 g of composite fiber, and 3 g of compatibilizer (vinyl triethoxysilane) were mixed to obtain a second rubber compound; 3) Mix the first rubber material and the second cross-linking material in a mass ratio of 10:1.

[0041] The preparation method of the layered transition metal oxide of this embodiment includes the following steps: S1: Add 0.25 mol aluminum nitrate, 0.1 mol cobalt nitrate and 500 mL deionized water to a stirred tank and stir thoroughly at room temperature to obtain precursor solution A; add 100 g melamine and 5 g manganese nitrate to 1000 mL of 30% by mass tetrabutylphosphine hydroxide solution and mix well to obtain precursor solution B; S2: Precursor solution A and precursor solution B are mixed evenly in a volume ratio of 0.35:1, the pH is adjusted to 8, and the mixture is aged at 60°C for 3 hours. The mixture is then heated to 500°C at a heating rate of 5°C and sintered in an air atmosphere for 4 hours. The sintered solid is washed with deionized water and anhydrous ethanol, and then dried, crushed, and ground to obtain a layered transition metal oxide.

[0042] The composite fiber of this embodiment is prepared by the following steps: A) 0.2 mol of zirconium polyacetylacetonate was dissolved in 1500 mL of methanol, and then 0.06 mol of tetraethyl orthosilicate was added and mixed uniformly to prepare a spinning solution 1; polyacrylonitrile was dried and dissolved in N,N-dimethylformamide, and heated to fully dissolve to prepare a spinning solution 2, wherein the mass percentage of polyacrylonitrile in the spinning solution 2 was controlled to be 15.5%; B) Spinning solution one and spinning solution two are transferred into a spinning solution tank, respectively, and conjugate electrospinning is performed through a positive electrode syringe and a negative electrode syringe, respectively, and hybrid fibers are collected on a receiving roller; wherein, spinning solution one is ejected from the positive electrode syringe, and the operating voltage of the positive electrode syringe is 16 kV, spinning solution two is ejected from the negative electrode syringe, and the operating voltage of the negative electrode syringe is 19 kV, the flow rate ratio of spinning solution one to spinning solution two is 1:0.7, the total flow rate of spinning solution one and spinning solution two is 5 mL / min, and the winding speed is 0.2 mm / s. Then, the hybrid fiber is pretreated at 200°C, then heated to 1100°C, kept warm for 5 minutes under inert gas, cooled, and pulverized to obtain a composite fiber.

[0043] Example 2 The preparation method of the organic silicon thermal conductive potting compound of this embodiment comprises the following steps: 1) 120 g of component A of organic silica gel (component A of Dow Corning SYLGARD 184), 20 g of flake graphite (325 mesh), 5 g of alumina (average particle size 100 μm), 5 g of boron nitride (average length 15 μm, average diameter 2 μm), and 5 g of layered transition metal oxide were mixed to obtain a first rubber compound; 2) 15 g of organic silica gel component B (component B of Dow Corning SYLGARD 184), 5 g of composite fiber, and 3 g of compatibilizer (vinyl triethoxysilane) were mixed to obtain a second rubber compound; 3) Mix the first rubber material and the second cross-linking material in a mass ratio of 10:1.

[0044] The preparation method of the layered transition metal oxide of this embodiment includes the following steps: S1: Add 0.25 mol aluminum nitrate, 0.1 mol cobalt nitrate and 500 mL deionized water to a stirred tank and stir thoroughly at room temperature to obtain precursor solution A; add 100 g melamine and 5 g manganese nitrate to 1000 mL of 30% by mass tetrabutylphosphine hydroxide solution and mix well to obtain precursor solution B; S2: Precursor solution A and precursor solution B are mixed evenly in a volume ratio of 0.35:1, the pH is adjusted to 8, and the mixture is aged at 60°C for 3 hours. Then, the mixture is heated to 600°C at a heating rate of 7.5°C and sintered in an air atmosphere for 4 hours. The sintered solid is washed with deionized water and anhydrous ethanol, and then dried, crushed, and ground to obtain a layered transition metal oxide.

[0045] The composite fiber of this embodiment is prepared by the following steps: A) 0.2 mol of zirconium polyacetylacetonate was dissolved in 1500 mL of methanol, and then 0.06 mol of tetraethyl orthosilicate was added and mixed uniformly to prepare a spinning solution 1; polyacrylonitrile was dried and dissolved in N,N-dimethylformamide, and heated to fully dissolve to prepare a spinning solution 2, wherein the mass percentage of polyacrylonitrile in the spinning solution 2 was controlled to be 15.5%; B) transferring the first spinning solution and the second spinning solution into a spinning solution tank, respectively, and performing conjugate electrospinning through a positive electrode syringe and a negative electrode syringe, respectively, and collecting the hybrid fibers on a receiving roller; wherein the first spinning solution is ejected from the positive electrode syringe, the operating voltage of the positive electrode syringe is 16 kV, and the second spinning solution is ejected from the negative electrode syringe, the operating voltage of the negative electrode syringe is 19 kV, the flow rate ratio of the first spinning solution to the second spinning solution is 1:0.7, the total flow rate of the first spinning solution and the second spinning solution is 5 mL / min, and the winding speed is 0.2 mm / s; The hybrid fiber is further modified in the following steps: S1: prepare a dopamine solution with a mass fraction of 10%, and immerse the hybrid fiber in the dopamine solution for 2 hours; S2: transfer the impregnated hybrid fiber to a metal oxide dispersion with a mass fraction of 25%, where the metal oxide is composed of yttrium oxide and copper oxide in a mass ratio of 0.5:1, continue the impregnation treatment, and then wash and dry; then pretreat the hybrid fiber at 280°C, then heat it to 1300°C, keep it warm under inert gas for 3.5 minutes, cool it, and crush it to obtain a composite fiber.

[0046] Example 3 The preparation method of the organic silicon thermal conductive potting compound of this embodiment comprises the following steps: 1) 120 g of component A of organic silica gel (component A of Dow Corning SYLGARD 184), 20 g of flake graphite (325 mesh), 5 g of alumina (average particle size 100 μm), 5 g of boron nitride (average length 15 μm, average diameter 2 μm), and 5 g of layered transition metal oxide were mixed to obtain a first rubber compound; 2) 15 g of organic silica gel component B (component B of Dow Corning SYLGARD 184), 5 g of composite fiber, and 3 g of compatibilizer (vinyl triethoxysilane) were mixed to obtain a second rubber compound; 3) Mix the first rubber material and the second cross-linking material in a mass ratio of 10:1.

[0047] The preparation method of the layered transition metal oxide of this embodiment includes the following steps: S1: Add 0.25 mol aluminum nitrate, 0.1 mol cobalt nitrate and 500 mL deionized water to a stirred tank and stir thoroughly at room temperature to obtain precursor solution A; add 100 g melamine and 5 g manganese nitrate to 1000 mL of 30% by mass tetrabutylphosphine hydroxide solution and mix well to obtain precursor solution B; S2: Precursor solution A and precursor solution B were mixed in a volume ratio of 0.35:1, the pH was adjusted to 8, and the mixture was aged at 60°C for 3 h. The mixture was then heated to 550°C at a heating rate of 6°C and sintered in an air atmosphere for 4 h. The sintered solid was washed with deionized water and anhydrous ethanol, and then dried, crushed, and ground to obtain a layered transition metal oxide.

[0048] The composite fiber of this embodiment is prepared by the following steps: A) 0.2 mol of zirconium polyacetylacetonate was dissolved in 1500 mL of methanol, and then 0.06 mol of tetraethyl orthosilicate was added and mixed uniformly to prepare a spinning solution 1; polyacrylonitrile was dried and dissolved in N,N-dimethylformamide, and heated to fully dissolve to prepare a spinning solution 2, wherein the mass percentage of polyacrylonitrile in the spinning solution 2 was controlled to be 15.5%; B) transferring the first spinning solution and the second spinning solution into a spinning solution tank, respectively, and performing conjugate electrospinning through a positive electrode syringe and a negative electrode syringe, respectively, and collecting the hybrid fibers on a receiving roller; wherein the first spinning solution is ejected from the positive electrode syringe, the operating voltage of the positive electrode syringe is 16 kV, and the second spinning solution is ejected from the negative electrode syringe, the operating voltage of the negative electrode syringe is 19 kV, the flow rate ratio of the first spinning solution to the second spinning solution is 1:0.7, the total flow rate of the first spinning solution and the second spinning solution is 5 mL / min, and the winding speed is 0.2 mm / s; The hybrid fiber is further modified in the following steps: S1: a dopamine solution with a mass fraction of 10% is prepared, and the hybrid fiber is immersed in the dopamine solution for 2 hours. After immersion for 30 minutes, L-hydroxyproline accounting for 6.5% of the mass of the dopamine solution is added; S2: the hybrid fiber after immersion is transferred to a metal oxide dispersion with a mass fraction of 25%, and the metal oxide is composed of yttrium oxide and copper oxide in a mass ratio of 0.3:1. The immersion treatment is continued, and then washed and dried; the hybrid fiber is then pretreated at 280°C, then heated to 1150°C, kept warm for 3.5 minutes under inert gas, cooled and crushed to obtain a composite fiber.

[0049] Control group 1 The preparation method of the organic silicon thermal conductive potting compound of this control group comprises the following steps: 1) 120 g of organic silica gel component A (component A of Dow Corning SYLGARD 184), 20 g of flake graphite (325 mesh), 5 g of alumina (average particle size 100 μm), 5 g of boron nitride (average length 15 μm, average diameter 2 μm), and 5 g of layered magnesium-aluminum hydrotalcite were mixed uniformly to obtain a first rubber compound; 2) Take 15g of organic silicone component B (component B of Dow Corning SYLGARD 184), 5g of carbon fiber, and 3g of compatibilizer (vinyl triethoxysilane) and mix them evenly to obtain a second rubber compound; 3) Mix the first rubber material and the second cross-linking material in a mass ratio of 10:1.

[0050] Control group 2 The preparation method of the organic silicon thermal conductive potting compound of this control group comprises the following steps: 1) 120 g of organic silica gel component A (component A of Dow Corning SYLGARD 184), 20 g of flake graphite (325 mesh), 5 g of alumina (average particle size 100 μm), 5 g of boron nitride (average length 15 μm, average diameter 2 μm), and 5 g of layered magnesium-aluminum hydrotalcite were mixed uniformly to obtain a first rubber compound; 2) 15 g of organic silica gel component B (component B of Dow Corning SYLGARD 184), 5 g of composite fiber, and 3 g of compatibilizer (vinyl triethoxysilane) were mixed to obtain a second rubber compound; 3) Mix the first rubber material and the second cross-linking material in a mass ratio of 10:1.

[0051] The composite fiber of the control group was prepared by the following steps: A) 0.2 mol of zirconium polyacetylacetonate was dissolved in 1500 mL of methanol, and then 0.06 mol of tetraethyl orthosilicate was added and mixed uniformly to prepare a spinning solution 1; polyacrylonitrile was dried and dissolved in N,N-dimethylformamide, and heated to fully dissolve to prepare a spinning solution 2, wherein the mass percentage of polyacrylonitrile in the spinning solution 2 was controlled to be 15.5%; B) Spinning solution one and spinning solution two are transferred into a spinning solution tank, respectively, and conjugate electrospinning is performed through a positive electrode syringe and a negative electrode syringe, respectively, and hybrid fibers are collected on a receiving roller; wherein, spinning solution one is ejected from the positive electrode syringe, and the operating voltage of the positive electrode syringe is 16 kV, spinning solution two is ejected from the negative electrode syringe, and the operating voltage of the negative electrode syringe is 19 kV, the flow rate ratio of spinning solution one to spinning solution two is 1:0.7, the total flow rate of spinning solution one and spinning solution two is 5 mL / min, and the winding speed is 0.2 mm / s. Then, the hybrid fiber is pretreated at 200°C, then heated to 1100°C, kept warm for 5 minutes under inert gas, cooled, and pulverized to obtain a composite fiber.

[0052] Performance testing 1. The thermal conductivity of the silicone thermal conductive potting compound of Examples 1-3 and Control Groups 1-2 was tested using a TC-3000E thermal conductivity tester in accordance with ISO 22007-2 and ASTM D5470. The test results are as follows: Figure 1 As shown, it can be seen that the thermal conductivity of the thermally conductive silicone of the present application can reach above 2.0W / mK, and the thermal resistance is less than 0.6 (50psi, ℃-in 2 / W), excellent thermal conductivity.

[0053] 2. Take the silicone thermal conductive potting glue of Examples 1-3 and Control Groups 1-2, degas, cure at room temperature, and test using a universal electronic tensile testing machine. The sample size is 10mm×4mm×1mm. The sample is stretched at a tensile rate of 200mm / min at room temperature. Each sample is tested 3 times to obtain the average value, which is the tensile strength and elongation at break of the sample. The test results are as follows: Figure 2As shown. According to ASTM2240, the hardness of the cured organic silicone thermal conductive potting compound can reach 65 (Shore 00). According to ASTMD149, ASTM D150 and ASTM D257, the electrical properties of the organic thermal conductive potting compound of this application can reach a breakdown voltage of more than 7.0 (Kv / mm) and a volume resistivity greater than 10 11 (Ω.cm), dielectric constant 6.0@1MHz, with good insulation properties.

[0054] 3. The layered transition metal oxide and composite fiber of Example 3 were tested by scanning electron microscope. The test results were as follows: Figure 3 and Figure 4 As shown, it can be seen that the layered transition metal oxide and composite fiber of the present application are uniform in size and can improve the mechanical properties and anti-settling properties of the organic silicone thermal conductive potting compound at both microscopic and macroscopic scales.

[0055] Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a silicone thermally conductive potting compound, characterized in that: The steps include: 1) Mixing the organic silica gel component A, flake graphite, aluminum oxide, boron nitride, and layered transition metal oxide to obtain a first rubber compound; 2) uniformly mixing the organic silica gel component B, the composite fiber, and the compatibilizer to obtain a second rubber compound; the composite fiber is made of polyacrylonitrile fiber and zirconium-based fiber; 3) Mix the first rubber material and the second cross-linking material evenly.

2. The method for preparing the thermally conductive silicone potting compound according to claim 1, wherein: The preparation method of the layered transition metal oxide comprises the following steps: S1: dissolving aluminum nitrate and cobalt nitrate in deionized water and stirring thoroughly to obtain precursor solution A; adding melamine and manganese nitrate to the tetrabutylphosphine hydroxide solution and mixing thoroughly to obtain precursor solution B; S2: Precursor solution A and precursor solution B are mixed evenly, the pH is adjusted to be weakly alkaline, and after aging treatment, the temperature is raised to 500-600° C. at a heating rate of 5-7.5° C. / min and sintered, and layered transition metal oxides are obtained after grinding.

3. The method for preparing the thermally conductive silicone potting compound according to claim 2, wherein: In step S1, the molar ratio of aluminum nitrate to cobalt nitrate in the precursor solution A is (2-3.5):1; And / or, in step S1, the mass ratio of melamine to manganese nitrate in the precursor solution B is 1:(0.03-0.05); And / or, in step S2, the volume ratio of precursor solution A to precursor solution B is (0.25-0.5):

1.

4. The method for preparing the thermally conductive silicone potting compound according to claim 1, wherein: The composite fiber is prepared by the following steps: A) Zirconium polyacetylacetonate is dissolved in methanol, and then ethyl orthosilicate is added and mixed uniformly to prepare a spinning solution 1; polyacrylonitrile is dissolved in N,N-dimethylformamide and heated to fully dissolve to prepare a spinning solution 2; B) The spinning solution 1 and the spinning solution 2 are conjugately electrospun to obtain hybrid fibers, and then the hybrid fibers are pretreated at a temperature of 200-280° C., then heated to 1100-1300° C., kept warm under an inert gas atmosphere, cooled, and pulverized to obtain composite fibers.

5. The method for preparing the thermally conductive silicone potting compound according to claim 4, wherein: In step A), the molar ratio of zirconium polyacetylacetonate to tetraethyl orthosilicate in the spinning solution 1 is 1:(0.1-0.35); And / or, in step A), the mass percentage of polyacrylonitrile in the second spinning solution is 15-20%; And / or, in the step B), the flow rate ratio of the spinning solution 1 to the spinning solution 2 is 1:(0.65-0.8).

6. The method for preparing the thermally conductive silicone potting compound according to claim 5, wherein: In step B), the hybrid fiber is further modified by the following steps: preparing a dopamine solution and immersing the hybrid fiber in the dopamine solution; transferring the immersed hybrid fiber to a metal oxide dispersion, continuing the immersion treatment, and then washing and drying.

7. The method for preparing the thermally conductive silicone potting compound according to claim 6, wherein: The mass percentage of the dopamine solution is 10-15%.

8. The method for preparing the thermally conductive silicone potting compound according to claim 6, wherein: During the impregnation process, L-hydroxyproline is added in an amount of 5-8% by mass of the dopamine solution; And / or, the metal oxide in the metal oxide dispersion is one or more of iron oxide, yttrium oxide, and copper oxide.

9. The method for preparing the thermally conductive silicone potting compound according to claim 8, wherein: The metal oxide is composed of yttrium oxide and copper oxide in a mass ratio of (0.3-0.5):

1.

10. A silicone thermally conductive potting compound, characterized by: The method is as described in any one of claims 1 to 9.

Images