High-thermal-conductivity potting silicone rubber, preparation method and application of high-thermal-conductivity potting silicone rubber in high-power inductor

Abstract

The invention relates to the technical field of silicone rubber, in particular to a compatilizer, high-thermal-conductivity potting silicone rubber, a preparation method of the high-thermal-conductivity potting silicone rubber and application of the high-thermal-conductivity potting silicone rubber in a high-power A hydrogen-containing silane ring body is used as an initial raw material, a compatilizer containing an epoxy group or an acetoacetic acid group, a siloxane group and a silicon hydrogen group is designed and synthesized, the compatilizer can react with amino on the surface of the amino silane coupling agent modified heat-conducting filler, and the heat-conducting filler is tightly combined through chemical bonds to form an aggregate with fine pore channels inside, so that the heat-conducting property of the heat-conducting filler is improved, and the heat-conducting property of the heat-conducting filler is improved. The overall viscosity of the mixed glue solution is reduced. And meanwhile, the compatibilizer improves the compatibility between the heat-conducting filler and an organic silicon matrix through chemical reaction, and a silicone rubber cured product with higher heat conductivity coefficient and lower CLTE is obtained through heat vulcanization. And finally, the epoxy group or acetoacetic acid group, which does not react with the amino group, in the compatilizer can also provide adhesion with the potting device, so that the potting requirement of the high-power inductor device can be met.

Description

Technical Field

[0001] This application relates to the field of silicone rubber technology, specifically to a compatibilizer, a high thermal conductivity potting silicone rubber, its preparation method, and its application in high-power inductor devices. Background Technology

[0002] High-power inductors are power electronic components that can store magnetic field energy and impede changes in current. Their core function is in high-power circuits, including new energy vehicles, photovoltaic inverters, and industrial power supplies. They are characterized by high rated current, large inductance, and high power density. High-power inductors are prone to generating a large amount of heat due to electromagnetic losses and copper losses during operation, so they have extremely high requirements for heat dissipation, insulation, and vibration resistance.

[0003] Encapsulation of high-power inductors can improve their heat dissipation, dustproofing, moisture resistance, insulation, and vibration resistance, and also contribute to miniaturization and weight reduction. Commonly used electronic encapsulation materials include epoxy resin, polyurethane, and silicone rubber. Epoxy resin encapsulants have high hardness, good adhesion, and a low coefficient of linear expansion (CLTE) (approximately 50-70 ppm / ℃), but the devices have poor resistance to high and low temperature cycling shocks and poor repairability. Polyurethane encapsulants have excellent elasticity and vibration resistance, but their heat resistance is significantly insufficient (operating temperature not exceeding 130℃). Silicone rubber, on the other hand, has good elasticity, a wide operating temperature range (-60-200℃), and good repairability, but its thermal conductivity is low (approximately 0.2 W·m). -1 ·k -1 The high CLTE temperature (>200ppm / ℃) cannot meet the high heat dissipation requirements of high-power inductor devices.

[0004] To address the low thermal conductivity of silicone rubber, current improvements involve filling it with thermally conductive and insulating fillers such as boron nitride (BN), alumina (Al2O3), aluminum nitride (AlN), or silicon carbide (SiC) to enhance the thermal conductivity of silicone potting compounds. However, even after filling, the thermal conductivity of the polymer-based composite material remains relatively low. This is because the thermally conductive fillers have significantly different chemical structures from the silicone matrix, resulting in poor compatibility and dispersibility, leading to high interfacial thermal resistance. Furthermore, using these thermally conductive and insulating fillers makes it difficult to simultaneously optimize thermal conductivity and mechanical flexibility. Attempts to improve thermal conductivity often result in material embrittlement, loss of adhesion and bonding properties to the potted device, and inability to meet the requirements of potting applications demanding strong vibration resistance and thermal shock resistance.

[0005] The reason why adding thermally conductive and insulating fillers to silicone rubber currently has unsatisfactory results is that the fillers have poor dispersibility and low interfacial compatibility with the silicone polymer matrix. The weak interfacial bonding between the fillers and the silicone polymer leads to thermal interface resistance, which limits the thermal conductivity of the composite material. Although filler surface modification and other methods have been adopted, it is still extremely difficult to achieve a balance between high thermal conductivity, low viscosity and strong adhesion. Therefore, there is an urgent need to develop potting compounds that combine high thermal conductivity, low viscosity, low CLTE and high adhesion. Summary of the Invention

[0006] The purpose of this invention is to overcome the above shortcomings and propose a compatibilizer, a high thermal conductivity potting silicone rubber, its preparation method and application. By designing and synthesizing a compatibilizer containing epoxy or acetoacetic acid groups with siloxane and silane groups, and using it in combination with aminosilane coupling agent surface-modified Al2O3, vinyl polysiloxane and hydrogen-containing silicone oil, a potting silicone rubber with high thermal conductivity, low viscosity, low CLTE and high adhesion is obtained.

[0007] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0008] Firstly, a compatibilizer, the molecular structure of which includes a polysiloxane core and side arms containing substituents, has the following general structural formula:

[0009] Where a, b, and c are positive integers greater than or equal to 1, and (a+b+c)≥3;

[0010] Preferably, (a+b+c)=3-5;

[0011] Further optimization yields (a+b+c) = 4 or 5.

[0012] R1 is selected from methyl, ethyl, or phenyl;

[0013] R2 contains one or both of the epoxy group and the acetoacetate group;

[0014] Preferably, R2 contains an epoxy group;

[0015] Preferably, R2 contains an acetoacetic acid group;

[0016] Further optimization, R2 is selected from... One or two of them.

[0017] R3, R4 and R5 may be the same or different, and at least one of them is selected from hydrolyzable alkoxy groups, including methoxy, ethoxy or isopropoxy.

[0018] Preferably, at least two of R3, R4 and R5 are selected from methoxy, ethoxy or isopropoxy.

[0019] Secondly, the compatibilizer preparation method described above uses a hydrogen-containing silane cyclic compound as the starting material, which is then reacted sequentially with an active monomer containing unsaturated bonds and a vinyl silane coupling agent via a hydrosilylation reaction.

[0020] The hydrogen-containing silane cyclic compound is selected from one of tetramethylcyclotetrasiloxane (D4H) or pentamethylcyclopentasiloxane (D5H);

[0021] The active monomer containing unsaturated bonds is selected from one or a combination of two of ethyl acetoacetate methacrylate (AAEM) and allyl glycidyl ether;

[0022] The vinyl silane coupling agent is selected from one of vinyltrimethoxysilane, vinyltriethoxysilane, or vinyltriisopropoxysilane;

[0023] Furthermore, the preparation method specifically includes the following steps:

[0024] S1. Hydrosilylation reaction of hydrogen-containing silane cyclic compounds with monomers containing unsaturated bonds is carried out using a platinum catalyst at 80-110℃ to obtain the hydrosilylation product.

[0025] S2. The hydrosilylation product obtained in step S1 is subjected to a hydrosilylation reaction with a vinylsilane coupling agent in the presence of a platinum catalyst at 80-110°C to obtain the hydrosilylation product.

[0026] S3. The hydrosilylation product obtained in step S2 is post-processed, including using an adsorbent to remove residual platinum catalyst and filtration to obtain the compatibilizer.

[0027] Preferably, in the hydrosilylation reaction in step S1 and step S2, nitrogen or inert gas is continuously introduced for protection during the reaction process;

[0028] Preferably, in the hydrosilylation reaction in step S1 and step S2, a solvent is added to effectively absorb and disperse the heat released by the reaction, help maintain the reaction temperature within a controllable range, and adjust the concentration of reactants to dissolve the platinum catalyst.

[0029] The solvent is selected from either toluene or xylene;

[0030] Preferably, in the hydrosilylation reaction in step S1 and step S2, a free radical polymerization inhibitor is added to prevent the first functional monomer containing unsaturated bonds from undergoing free radical polymerization side reactions.

[0031] The free radical polymerization inhibitor is selected from phenolic polymerization inhibitors;

[0032] Preferably, the free radical polymerization inhibitor is selected from hydroquinone, p-hydroxyanisole, or 2,6-di-tert-butyl-p-cresol;

[0033] Preferably, the hydrosilylation reaction in step S1 and step S2 is measured by infrared spectroscopy at 1640-1660 cm⁻¹. -1 The disappearance of the absorption peak at a certain point is taken as the end point of the reaction;

[0034] The platinum catalysts in steps S1 and S2 are selected from one or more combinations of platinum-isopropanol complex catalysts, platinum-ene complex catalysts, platinum-phosphine amine complex catalysts, and platinum-(N-heterocyclic carbene) complexes.

[0035] Preferably, the platinum catalyst is selected from platinum-olefin complex catalysts;

[0036] Further preferred, the platinum-olefin complex catalyst is selected from: platinum-divinyltetramethyldisiloxane complex.

[0037] The monomer containing unsaturated bonds in step S1 is selected from ethyl acetoacetate methacrylate and / or allyl glycidyl ether;

[0038] The adsorbent in step S3 is selected from activated carbon;

[0039] Preferably, step S3 further includes removing the solvent by vacuum distillation.

[0040] Thirdly, the compatibilizers mentioned above are used in the preparation of potting silicone rubber.

[0041] Fourthly, a potting silicone rubber includes component A and component B, wherein component A includes: vinyl-terminated poly(dimethylsiloxane), methyl-terminated poly(dimethyl-co-methylvinylsiloxane), thermally conductive filler, and platinum catalyst;

[0042] Component B includes: vinyl-terminated poly(dimethylsiloxane), aminosilane coupling agent modified thermally conductive filler, methyl-terminated poly(methylhydro-co-dimethylsiloxane), inhibitor, and the compatibilizers described above;

[0043] The vinyl content of the vinyl-terminated poly(dimethylsiloxane) is 0.1-0.4 wt%.

[0044] Preferably, the vinyl content of the vinyl-terminated poly(dimethylsiloxane) is 0.2-0.3 wt%.

[0045] The vinyl content of the methyl-terminated poly(dimethyl-co-methylvinylsiloxane) is 0.1-0.4 wt%.

[0046] Preferably, the vinyl content of the methyl-terminated poly(dimethyl-co-methylvinylsiloxane) is 0.2-0.3 wt%.

[0047] The thermally conductive filler is selected from Al2O3;

[0048] Preferably, the specific method for modifying thermally conductive fillers with aminosilane coupling agents includes:

[0049] S1. Add the aminosilane coupling agent to a mixed solution of water and ethanol for hydrolysis to obtain a hydrolysate;

[0050] S2. Heat the thermally conductive filler to 100-120℃ and spray the hydrolysate prepared in step S1 onto it under mechanical stirring to perform surface modification.

[0051] S3. Wash the surface-modified thermally conductive filler with ethanol to remove unreacted free silane coupling agent.

[0052] S4. Dry the surface-modified thermally conductive filler.

[0053] The platinum catalyst is selected from platinum-olefin complex catalysts;

[0054] Preferably, the platinum-olefin complex catalyst is selected from platinum-divinyltetramethyldisiloxane complex.

[0055] The aminosilane coupling agent contains at least one primary amino group and at least one hydrolyzable Si-OR group, wherein R is selected from methyl, ethyl or isopropyl.

[0056] Preferably, the aminosilane coupling agent is selected from any one or more of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldimethoxymethylsilane, 3-aminopropyldiethoxymethylsilane, 3-aminopropylmethoxydimethylsilane, 3-aminopropylethoxydimethylsilane, N-aminoethyl-3-aminopropyltrimethoxysilane, N-aminoethyl-3-aminopropyltriethoxysilane, N-aminoethyl-3-aminopropylmethyldimethoxysilane, and N-aminoethyl-3-aminopropylmethyldiethoxysilane.

[0057] The hydrogen content of the methyl-terminated poly(methylhydro-co-dimethylsiloxane) is 0.1-2 wt%.

[0058] Preferably, the hydrogen content of the methyl-terminated poly(methylhydro-co-dimethylsiloxane) is 1-2 wt%.

[0059] The inhibitor is selected from alkynols and their derivatives. By coordinating with the center of the platinum catalyst, its activity is temporarily blocked, which is used to controllably delay the reaction, prolong the working time after the A and B components are mixed, ensure the fluidity of the mixed solution, and prevent premature vulcanization.

[0060] Preferably, the inhibitor is selected from one of methylbutynol, dimethylethynol, vinylcyclohexanol, 3-methyl-1-pentyn-3-ol or 3,5-dimethyl-1-hexyn-3-ol.

[0061] Furthermore, component A of the potting silicone rubber, by weight percentage, includes: 80-100 parts of vinyl-terminated poly(dimethylsiloxane), 20-40 parts of methyl-terminated poly(dimethyl-co-methylvinylsiloxane), 180-220 parts of thermally conductive filler, and 0.5-2.0 parts of platinum catalyst.

[0062] Furthermore, component B of the potting silicone rubber, by weight percentage, includes: 60-100 parts of vinyl-terminated poly(dimethylsiloxane), 500-700 parts of aminosilane coupling agent modified thermally conductive filler, 10-40 parts of methyl-terminated poly(methylhydro-co-dimethylsiloxane), 20-50 parts of compatibilizer, and 0.5-2.0 parts of inhibitor.

[0063] Fifthly, the preparation method of the potting silicone rubber described above includes:

[0064] The preparation method of component A is to mechanically mix the prescribed amounts of vinyl-terminated polydimethylsiloxane, methyl-terminated poly(dimethyl-co-methylvinylsiloxane) and thermally conductive filler, and then mechanically mix them with the prescribed amounts of platinum catalyst.

[0065] Preferably, the specific steps of the preparation method for component A include:

[0066] S1. Under vacuum and temperature conditions of 120-180℃, the formulated amounts of vinyl-terminated polydimethylsiloxane, methyl-terminated poly(dimethyl-co-methylvinylsiloxane), and thermally conductive filler are mechanically mixed for 1-4 hours to obtain a homogeneous mixture.

[0067] S2. Cool the mixture from step S1 to room temperature and mechanically mix it with the prescribed amount of platinum catalyst under vacuum for 0.5-1 hour to obtain component A.

[0068] The preparation method of component B is as follows: the formulated amount of aminosilane coupling agent modified thermally conductive filler and compatibilizer are mechanically mixed, then mechanically mixed with vinyl-terminated polydimethylsiloxane, and finally mechanically mixed with the formulated amount of hydrogen-containing silicone oil and inhibitor.

[0069] Preferably, the specific steps of the preparation method for component B include:

[0070] S1. Under vacuum conditions and a temperature of 120-180℃, the surface-modified thermally conductive filler and compatibilizer of the specified amount are mechanically mixed for 0.5-3 hours to obtain a mixture of compatibilizer and thermally conductive filler.

[0071] S2. Add the formulated amount of vinyl-terminated polydimethylsiloxane to the mixture of compatibilizer and thermally conductive filler prepared in step S1, and continue mechanical mixing for 0.5-3 hours to obtain a homogeneous mixture.

[0072] S3. Cool the mixture prepared in step S3 to room temperature, and mechanically mix it with the prescribed amount of hydrogen-containing silicone oil and inhibitor under vacuum conditions for 0.5-1 hour to obtain component B.

[0073] Preferably, a planetary mixer is used to mechanically mix the different materials during the preparation of components A and B.

[0074] Sixthly, a potting silicone rubber cured product is obtained by hot vulcanization of the potting silicone rubber described above;

[0075] Preferably, the thermal conductivity of the potted silicone rubber cured material is not less than 2.6 W·m. -1 • K-1, with a linear expansion coefficient not exceeding 75ppm / ℃, and an lap shear strength to the PCB board not less than 0.8MPa.

[0076] Furthermore, the specific steps of the thermal vulcanization include:

[0077] S1. Use mechanical stirring to mix components A and B evenly to obtain a mixed adhesive solution;

[0078] S2. Vacuum degassing is performed on the mixed adhesive solution obtained in step S1;

[0079] S3. Quickly inject the vacuum-degassed adhesive from step S2 into the mold for potting and sealing.

[0080] S4. Curing the sample that was potted in step S3, with a heating rate not exceeding 10℃ / min, first baking at 70-90℃ for 1-3 hours, and then baking at 100-120℃ for 1-3 hours.

[0081] S5. Allow the sample cured in step S4 to cool naturally to room temperature and demold to obtain the potted silicone rubber cured product.

[0082] Seventhly, the application of the above-mentioned potting silicone rubber cured material in high-power inductor devices.

[0083] The beneficial effects of the technical solution in this application are:

[0084] 1. Using hydrogen-containing silane cyclic compounds as starting materials, a compatibilizer containing epoxy or acetoacetic acid groups and siloxane and Si-H groups is designed and synthesized. This compatibilizer can react with the amino groups on the surface of the amino silane coupling agent modified by the amino silane coupling agent. Through chemical bonds, the thermally conductive fillers are tightly bound together to form aggregates with fine pores inside. During the mixing and mechanical stirring of component B and component A, the high-viscosity vinyl polydimethylsiloxane fills the pores through capillary action, reducing the frictional interaction between particles, thereby reducing the overall viscosity of the mixed adhesive obtained after mixing components A and B.

[0085] 2. The compatibilizer also retains the silane-hydrogen bonds that can react with vinyl polydimethylsiloxane, thereby improving the compatibility between the thermally conductive filler and the organosilicon matrix. After thermal vulcanization, a silicone rubber cured product with higher thermal conductivity and lower CLTE is obtained, which in particular improves the defect of excessively high CLTE of polysiloxane matrix.

[0086] 3. Unreacted epoxy or acetoacetic acid groups can also provide adhesion between the encapsulated device and the compatibilizer can also be used as a tackifier. The silicone rubber cured product obtained after heat vulcanization has an overlap shear strength of not less than 0.87 MPa against rigid printed circuit board (PCB) materials, which can meet the encapsulation requirements of high-power inductor devices.

[0087] 4. The compatibilizer and aminosilane coupling agent are used together to modify the thermally conductive filler as the key component of the B component of potting silicone rubber, thereby achieving a balance of multiple properties such as high thermal conductivity, low viscosity, low CLTE and high adhesion of the cured silicone rubber. Attached Figure Description

[0088] To more clearly illustrate the technical solutions in the embodiments of this application and to more completely understand this application and its beneficial effects, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0089] Figure 1 XPS spectra of surface-modified Al2O3 with aminosilane coupling agent and unmodified Al2O3 in Examples 1-2 are compared, where a) is unmodified Al2O3; b) is surface-modified Al2O3 with KH550; and c) is surface-modified Al2O3 with aminopropylmethyldiethoxysilane.

[0090] Figure 2 Thermogravimetric analysis (TGA) diagrams of surface-modified Al2O3 and unmodified Al2O3 with aminosilane coupling agents in Examples 1-2 are shown, where a) is unmodified Al2O3; b) is surface-modified Al2O3 with KH550; and c) is surface-modified Al2O3 with aminopropylmethyldiethoxysilane.

[0091] Figure 3 The infrared spectra of the compatibilizer prepared in Example 7 are compared with those of the raw materials, where a, D5H; b, vinyltriethoxysilane; c, allyl glycidyl ether; and d, the compatibilizer prepared in Example 7. Detailed Implementation

[0092] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present invention. It should be noted that the terminology used herein is only for describing specific implementations and is not intended to limit the exemplary implementations of the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form as well. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0093] Unless otherwise stated or in case of contradiction, the terms or phrases used herein shall have the following meanings:

[0094] The terms "and / or," "or / and," and "and / or" as used herein include any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. It should be noted that when at least three items are connected by at least two conjunctions selected from "and / or," "or / and," and "and / or," it should be understood that in this application, the technical solution undoubtedly includes technical solutions connected by "logical AND," and also undoubtedly includes technical solutions connected by "logical OR." For example, "A and / or B" includes three parallel solutions: A, B, and A+B. For example, the technical solution of "A, and / or, B, and / or, C, and / or, D" includes any one of A, B, C, and D (that is, a technical solution that is connected by "logical OR"), as well as any and all combinations of A, B, C, and D, that is, combinations of any two or three of A, B, C, and D, and also combinations of all four of A, B, C, and D (that is, a technical solution that is connected by "logical AND").

[0095] In this application, the terms "multiple", "various", "multiple times", "multi-dimensional", etc., unless otherwise specified, refer to a quantity greater than or equal to 2. For example, "one or more" means one or more than or equal to two.

[0096] In this application, "optionally," "optionally," and "optional" mean that something is optional, that is, it means that it is selected from either "with" or "without." If there are multiple "optional" entries in a technical solution, unless otherwise specified, and there are no contradictions or mutual constraints, each "optional" entry shall be independent.

[0097] In this application, the technical features described in an open-ended manner include both closed-ended technical solutions composed of the listed features and open-ended technical solutions containing the listed features.

[0098] In this application, numerical intervals (i.e., numerical ranges) are involved. Unless otherwise specified, the selected numerical distributions within the aforementioned numerical intervals are considered continuous and include the two endpoints (i.e., the minimum and maximum values) of the numerical range, as well as every value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints. In this document, this is equivalent to directly listing every integer. For example, if t is an integer selected from 1 to 10, it means that t is any integer selected from the group of integers consisting of 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10. Furthermore, when multiple ranges are provided to describe features or characteristics, these ranges can be merged. In other words, unless otherwise specified, the ranges disclosed herein should be understood to include any and all subranges to which they are included.

[0099] Unless otherwise specified, the temperature parameters in this application are permitted to be either constant-temperature treatment or variations within a certain temperature range. It should be understood that the constant-temperature treatment allows temperature fluctuations within the precision range of the instrument control, such as ±5℃, ±4℃, ±3℃, ±2℃, or ±1℃.

[0100] All references to documents mentioned in this application are incorporated herein by reference as if each document were individually incorporated herein by reference. Unless they conflict with the inventive purpose and / or technical solution of this application, all cited documents are incorporated herein by reference in their entirety and for all purposes. When citing documents in this application, the definitions of relevant technical features, terms, nouns, phrases, etc., are also incorporated herein by reference. When citing documents in this application, examples and preferred embodiments of the cited technical features may also be incorporated herein by reference, but only to the extent that they enable the implementation of this application. It should be understood that when the cited content conflicts with the description in this application, this application shall prevail or modifications shall be made adaptably to the description in this application.

[0101] Unless otherwise specified, the experimental conditions used in the examples are generally in accordance with conventional conditions in the art or the conditions recommended by the reagent company. Unless otherwise specified, the materials and reagents used in the examples can be purchased commercially.

[0102] In the embodiments, the thermally conductive filler used is Al2O3 filler, which is selected from high-purity α-Al2O3, wherein the α-phase Al2O3 content is >90%, the Al2O3 content is ≥99.9%, and the specific surface area is ≤5m². 2 / g, with an average particle size D50 of (20±5)μm.

[0103] Example 1

[0104] The surface modification of Al2O3 filler with aminopropyltriethoxysilane (KH550) was carried out by first adding 11.1 g of aminopropyltriethoxysilane (KH550) to a mixed solution of 2.7 g of water and 21 g of ethanol, and stirring at 40 °C for 1 hour to obtain KH550 hydrolysate. Then, 1 kg of Al2O3 powder was added to a high-speed mixer, heated to 105 °C, and the KH550 hydrolysate was sprayed onto the Al2O3 filler powder. The mixture was stirred at 800 rpm for 1 hour to complete the reaction.

[0105] The modified Al2O3 packing was then washed and filtered three times with 200 mL of anhydrous ethanol to separate the unreacted free KH550. The modified Al2O3 packing was then vacuum dried at 50 °C for 12 hours.

[0106] Example 2

[0107] The surface modification of Al₂O₃ filler with aminopropylmethyldiethoxysilane was carried out by first adding 9.6 g of aminopropylmethyldiethoxysilane to a mixed solution of 1.8 g of water and 21 g of ethanol, and stirring at 40 °C for 1 hour to obtain an aminopropylmethyldiethoxysilane hydrolysate. Then, 1 kg of Al₂O₃ powder was added to a high-speed mixer, and the mixture was heated to 105 °C before spraying the aminopropylmethyldiethoxysilane hydrolysate onto the Al₂O₃ powder. The mixture was stirred at 800 rpm for 1 hour to complete the reaction.

[0108] The modified Al2O3 packing was then washed and filtered three times with 200 mL of anhydrous ethanol to separate the unreacted free aminopropylmethyldiethoxysilane. The modified Al2O3 packing was then vacuum dried at 50 °C for 12 hours.

[0109] Example 3

[0110] Preparation of the compatibilizer: Tetramethylcyclotetrasiloxane (D4H) was used as the initial hydrogen-containing ring. The mixture was heated to 88°C under nitrogen protection. Then, 42.8 g (0.2 mol) of ethyl acetoacetate methacrylate (AAEM), 0.4 g of the polymerization inhibitor p-hydroxyanisole, and 0.15 g of platinum catalyst PT-5000 (platinum-divinyltetramethyldisiloxane complex) were added dropwise to 48.1 g (0.2 mol) of D4H dissolved in 50 mL of toluene. After 0.5 hours of dropwise addition, the reaction mixture was kept at this temperature for 1 hour. FTIR analysis showed that the reaction mixture was within the range of 1640-1660 cm⁻¹. -1 The absorption peak of the C=C double bond disappeared. Subsequently, 38.1 g (0.2 mol) of vinyltriethoxysilane and 0.15 g of platinum catalyst PT-5000 (platinum-divinyltetramethyldisiloxane complex) were added dropwise at this temperature. After the addition was completed in 0.5 hours, the reaction mixture was kept at this temperature for 1 hour. FTIR analysis showed that the reaction mixture was at 1640-1660 cm⁻¹. -1 The absorption peak of the C=C double bond disappeared. 20g of activated carbon was added in batches to adsorb the platinum catalyst in the reaction mixture. The catalyst was removed by filtration, and the solvent was removed by vacuum distillation of the filtrate to obtain the compatibilizer.

[0111] Example 4

[0112] Preparation of the compatibilizer: Tetramethylcyclotetrasiloxane (D4H) was used as the initial hydrogen-containing ring. The mixture was heated to 88°C under nitrogen protection. Then, 53.6 g (0.25 mol) of ethyl acetoacetate methacrylate (AAEM), 0.45 g of the polymerization inhibitor p-hydroxyanisole, and 0.15 g of platinum catalyst PT-5000 (platinum-divinyltetramethyldisiloxane complex) were added dropwise to 48.1 g (0.2 mol) of D4H dissolved in 50 mL of toluene. After 0.5 hours of dropwise addition, the reaction mixture was kept at this temperature for 1 hour. FTIR analysis showed that the reaction mixture was within the range of 1640-1660 cm⁻¹. -1 The absorption peak of the C=C double bond disappeared. Subsequently, 47.6 g (0.25 mol) of vinyltriethoxysilane and 0.15 g of platinum catalyst PT-5000 (platinum-divinyltetramethyldisiloxane complex) were added dropwise at this temperature. After the addition was completed in 0.5 hours, the reaction mixture was kept at this temperature for 1 hour. FTIR analysis showed that the reaction mixture was in the range of 1640-1660 cm⁻¹. -1 The absorption peak of the C=C double bond disappeared. 20g of activated carbon was added in batches to adsorb the platinum catalyst in the reaction mixture. The catalyst was removed by filtration, and the solvent was removed by vacuum distillation of the filtrate to obtain the compatibilizer.

[0113] Example 5

[0114] Preparation of compatibilizer: 22.8 g (0.2 mol) of allyl glycidyl ether was used instead of AAEM, and the remaining raw materials and operating steps were the same as in Example 3.

[0115] Example 6

[0116] Preparation of compatibilizer: 28.5 g (0.25 mol) of allyl glycidyl ether was used instead of AAEM, and the remaining raw materials and operating steps were the same as in Example 4.

[0117] Example 7

[0118] Preparation of the compatibilizer: Pentamethylcyclopentasiloxane (D5H) was used as the initial hydrogen-containing ring. The mixture was heated to 88°C under nitrogen protection. Then, 28.5 g (0.25 mol) of allyl glycidyl ether, 0.45 g of the polymerization inhibitor p-hydroxyanisole, and 0.2 g of platinum catalyst PT-5000 (platinum-divinyltetramethyldisiloxane complex) were added dropwise to 60.1 g (0.2 mol) of D5H dissolved in 50 mL of toluene. After 0.5 hours of dropwise addition, the reaction mixture was kept at this temperature for 1 hour. FTIR analysis showed that the reaction mixture was within the range of 1640-1660 cm⁻¹. -1 The absorption peak of the C=C double bond disappeared. Subsequently, 28.5 g (0.15 mol) of vinyltriethoxysilane and 0.1 g of platinum catalyst PT-5000 (platinum-divinyltetramethyldisiloxane complex) were added dropwise at this temperature. After the addition was completed in 0.5 hours, the reaction mixture was kept at this temperature for 1 hour. FTIR analysis showed that the reaction mixture was at 1640-1660 cm⁻¹. -1 The absorption peak of the C=C double bond disappeared. 20g of activated carbon was added in batches to adsorb the platinum catalyst in the reaction mixture. The catalyst was removed by filtration, and the solvent was removed by vacuum distillation of the filtrate to obtain the compatibilizer.

[0119] Example 8

[0120] Preparation of the compatibilizer: Pentamethylcyclopentasiloxane (D5H) was used as the initial hydrogen-containing ring. The mixture was heated to 88°C under nitrogen protection. Then, 53.6 g (0.25 mol) of ethyl acetoacetate methacrylate (AAEM), 0.45 g of the polymerization inhibitor p-hydroxyanisole, and 0.2 g of platinum catalyst PT-5000 (platinum-divinyltetramethyldisiloxane complex) were added dropwise to 60.1 g (0.2 mol) of D5H dissolved in 50 mL of toluene. After 0.5 hours of dropwise addition, the reaction mixture was kept at this temperature for 1 hour. FTIR analysis showed that the reaction mixture was within the range of 1640-1660 cm⁻¹. -1 The absorption peak of the C=C double bond disappeared. Subsequently, 37.1 g (0.25 mol) of vinyltrimethoxysilane and 0.2 g of platinum catalyst PT-5000 (platinum-divinyltetramethyldisiloxane complex) were added dropwise at this temperature. After the addition was completed in 0.5 hours, the reaction mixture was kept at this temperature for 1 hour. FTIR analysis showed that the reaction mixture was in the range of 1640-1660 cm⁻¹. -1The absorption peak of the C=C double bond disappeared. 25g of activated carbon was added in batches to adsorb the platinum catalyst in the reaction mixture. The catalyst was removed by filtration, and the solvent was removed by vacuum distillation of the filtrate to obtain the compatibilizer.

[0121] Example 9

[0122] Preparation of the compatibilizer: Pentamethylcyclopentasiloxane (D5H) was used as the initial hydrogen-containing ring. The mixture was heated to 88°C under nitrogen protection. Then, 75.0 g (0.35 mol) of ethyl acetoacetate methacrylate (AAEM), 0.5 g of the polymerization inhibitor p-hydroxyanisole, and 0.2 g of platinum catalyst PT-5000 (platinum-divinyltetramethyldisiloxane complex) were added dropwise to 60.1 g (0.2 mol) of D5H dissolved in 50 mL of toluene. After 0.5 hours of dropwise addition, the reaction mixture was kept at this temperature for 1 hour. FTIR analysis showed that the reaction mixture was within the range of 1640-1660 cm⁻¹. -1 The absorption peak of the C=C double bond disappeared. Subsequently, 37.1 g (0.25 mol) of vinyltrimethoxysilane and 0.2 g of platinum catalyst PT-5000 (platinum-divinyltetramethyldisiloxane complex) were added dropwise at this temperature. After the addition was completed in 0.5 hours, the reaction mixture was kept at this temperature for 1 hour. FTIR analysis showed that the reaction mixture was in the range of 1640-1660 cm⁻¹. -1 The absorption peak of the C=C double bond disappeared. 25g of activated carbon was added in batches to adsorb the platinum catalyst in the reaction mixture. The catalyst was removed by filtration, and the solvent was removed by vacuum distillation of the filtrate to obtain the compatibilizer.

[0123] Example 10

[0124] Preparation of the compatibilizer: Pentamethylcyclopentasiloxane (D5H) was used as the initial hydrogen-containing ring. The mixture was heated to 88°C under nitrogen protection. Then, 42.8 g (0.2 mol) of ethyl acetoacetate methacrylate (AAEM), 22.8 g (0.2 mol) of allyl glycidyl ether, 0.45 g of polymerization inhibitor p-hydroxyanisole, and 0.3 g of platinum catalyst PT-5000 (platinum-divinyltetramethyldisiloxane complex) were added dropwise to 60.1 g (0.2 mol) of D5H dissolved in 50 mL of toluene. After 0.5 hours of dropwise addition, the reaction mixture was kept at this temperature for 1 hour. FTIR analysis showed that the reaction mixture was within the range of 1640-1660 cm⁻¹. -1 The absorption peak of the C=C double bond disappeared. Subsequently, 29.6 g (0.2 mol) of vinyltrimethoxysilane and 0.2 g of platinum catalyst PT-5000 (platinum-divinyltetramethyldisiloxane complex) were added dropwise at this temperature. After the addition was completed in 0.5 hours, the reaction mixture was kept at this temperature for 1 hour. FTIR analysis showed that the reaction mixture was at 1640-1660 cm⁻¹. -1The absorption peak of the C=C double bond disappeared. 25g of activated carbon was added in batches to adsorb the platinum catalyst in the reaction mixture. The catalyst was removed by filtration, and the solvent was removed by vacuum distillation of the filtrate to obtain the compatibilizer.

[0125] Example 11

[0126] Component A of the potting silicone rubber, by weight percentage, includes: 4 × 10⁻⁶ at 25°C. 5 Vinyl-terminated poly(dimethylsiloxane) with a viscosity of cps (0.24 wt% vinyl content) 90 parts, 2 × 10 at 25°C 4 The composition consists of 30 parts of methyl-terminated poly(dimethyl-co-methyl vinylsiloxane) (vinyl content 0.24 wt%) with cps viscosity, 200 parts of Al2O3 filler, and 0.8 parts of PT-5000 platinum-divinyltetramethyldisiloxane complex.

[0127] Component B of the potting silicone rubber, by weight percentage, includes: 4 × 10⁻⁶ at 25°C. 5 The following components were prepared: 80 parts of vinyl-terminated poly(dimethylsiloxane) with cps viscosity (vinyl content 0.24 wt%), 600 parts of aminopropyltriethoxysilane surface-modified Al2O3 filler prepared in Example 1, 15 parts of methyl-terminated poly(methylhydro-co-dimethylsiloxane) (hydrogen content 1.6 wt%), 30 parts of compatibilizer prepared in Example 3, and 1.0 part of inhibitor 3-methyl-1-pentyn-3-ol.

[0128] The preparation method of potting silicone rubber specifically includes: under vacuum conditions of -0.08 MPa and 150°C, the formulated amount of aminopropyltriethoxysilane surface-modified Al2O3 filler prepared in Example 1 and the compatibilizer prepared in Example 3 are kneaded for 1 hour using a planetary mixer, and then the formulated amount of vinyl-terminated poly(dimethylsiloxane) is added and kneaded for 1 hour to obtain a uniform silicone rubber-Al2O3 mixture. After cooling to room temperature, the formulated amount of methyl-terminated poly(methylhydro-co-dimethylsiloxane) and the inhibitor 3-methyl-1-pentyn-3-ol are mixed with the cooled silicone rubber-Al2O3 mixture under vacuum conditions for 0.5 hours to obtain component B.

[0129] Under vacuum conditions of -0.08 MPa and 150 °C, the formulated amounts of vinyl-terminated poly(dimethylsiloxane) (vinyl content 0.24 wt%), methyl-terminated poly(dimethyl-co-methylvinylsiloxane), and Al2O3 filler were kneaded for 2 hours using a planetary mixer to obtain a homogeneous silicone rubber-Al2O3 mixture. After cooling to room temperature, the formulated amounts of PT-5000 platinum-divinyltetramethyldisiloxane complex were mixed with the cooled silicone rubber-Al2O3 mixture under vacuum conditions for 0.5 hours to obtain component A.

[0130] Example 12

[0131] Component A of the potting silicone rubber is the same as in Example 11;

[0132] Component B of the potting silicone rubber, by weight percentage, includes: 4 × 10⁻⁶ at 25°C. 5 The following ingredients were used: 80 parts of vinyl-terminated poly(dimethylsiloxane) with cps viscosity (vinyl content 0.24 wt%), 650 parts of aminopropylmethyldiethoxysilane surface-modified Al2O3 filler prepared in Example 2, 15 parts of methyl-terminated poly(methylhydro-co-dimethylsiloxane) (hydrogen content 1.6 wt%), 33 parts of compatibilizer prepared in Example 4, and 1.0 part of inhibitor 3-methyl-1-pentyn-3-ol;

[0133] The preparation method of the potting silicone rubber is the same as that in Example 11.

[0134] Example 13

[0135] Component A of the potting silicone rubber is the same as in Example 11;

[0136] Component B of the potting silicone rubber uses 30 parts of the compatibilizer prepared in Example 5, and the rest is the same as in Example 11;

[0137] The preparation method of the potting silicone rubber is the same as that in Example 11.

[0138] Example 14

[0139] Component A of the potting silicone rubber is the same as in Example 11;

[0140] Component B of the potting silicone rubber used 33 parts of the compatibilizer prepared in Example 6, and the rest was the same as in Example 12;

[0141] The preparation method of the potting silicone rubber is the same as that in Example 11.

[0142] Example 15

[0143] Component A of the potting silicone rubber is the same as in Example 11;

[0144] Component B of the potting silicone rubber, by weight percentage, includes: 4 × 10⁻⁶ at 25°C. 5 The following components were used: 80 parts of vinyl-terminated poly(dimethylsiloxane) with cps viscosity (vinyl content 0.24 wt%), 600 parts of aminopropyltriethoxysilane surface-modified Al2O3 filler prepared in Example 1, 15 parts of methyl-terminated poly(methylhydro-co-dimethylsiloxane) (hydrogen content 1.6 wt%), 24 parts of compatibilizer prepared in Example 7, and 1.0 part of inhibitor 3-methyl-1-pentyn-3-ol.

[0145] The preparation method of the potting silicone rubber is the same as that in Example 11.

[0146] Example 16

[0147] Component A of the potting silicone rubber is the same as in Example 11;

[0148] Component B of the potting silicone rubber, by weight percentage, includes: 4 × 10⁻⁶ at 25°C. 5 The following components were used: 80 parts of vinyl-terminated poly(dimethylsiloxane) with cps viscosity (vinyl content 0.24 wt%), 600 parts of aminopropylmethyldiethoxysilane surface-modified Al2O3 filler prepared in Example 2, 15 parts of methyl-terminated poly(methylhydro-co-dimethylsiloxane) (hydrogen content 1.6 wt%), 25 parts of compatibilizer prepared in Example 6, and 1.0 part of inhibitor 3-methyl-1-pentyn-3-ol.

[0149] The preparation method of the potting silicone rubber is the same as that in Example 11.

[0150] Example 17

[0151] Component A of the potting silicone rubber is the same as in Example 11;

[0152] Component B of the potting silicone rubber, by weight percentage, includes: 4 × 10⁻⁶ at 25°C. 5 The following components were used: 80 parts of vinyl-terminated poly(dimethylsiloxane) with cps viscosity (vinyl content 0.24 wt%), 600 parts of aminopropyltriethoxysilane surface-modified Al2O3 filler prepared in Example 1, 15 parts of methyl-terminated poly(methylhydro-co-dimethylsiloxane) (hydrogen content 1.6 wt%), 25 parts of compatibilizer prepared in Example 6, and 1.0 part of inhibitor 3-methyl-1-pentyn-3-ol.

[0153] The preparation method of the potting silicone rubber is the same as that in Example 11.

[0154] Example 18

[0155] Component A of the potting silicone rubber is the same as in Example 11;

[0156] Component B of the potting silicone rubber, by weight percentage, includes: 4 × 10⁻⁶ at 25°C. 5 The following components were used: 80 parts of vinyl-terminated poly(dimethylsiloxane) with cps viscosity (vinyl content 0.24 wt%), 600 parts of aminopropyltriethoxysilane surface-modified Al2O3 filler prepared in Example 1, 15 parts of methyl-terminated poly(methylhydro-co-dimethylsiloxane) (hydrogen content 1.6 wt%), 25 parts of compatibilizer prepared in Example 6, and 1.0 part of inhibitor 3-methyl-1-pentyn-3-ol.

[0157] The preparation method of the potting silicone rubber is the same as that in Example 11.

[0158] Comparative Example 1

[0159] Component A of the potting silicone rubber is the same as in Example 11;

[0160] Component B of the potting silicone rubber, by weight percentage, includes: 4 × 10⁻⁶ at 25°C. 5 The composition includes 80 parts of vinyl-terminated poly(dimethylsiloxane) with a viscosity of cps (vinyl content 0.24 wt%), 600 parts of Al2O3 filler, 15 parts of methyl-terminated poly(methylhydro-co-dimethylsiloxane) (hydrogen content 1.6 wt%), 24 parts of the compatibilizer prepared in Example 7, and 1.0 part of the inhibitor 3-methyl-1-pentyn-3-ol.

[0161] The preparation method of the potting silicone rubber is the same as that in Example 11.

[0162] Comparative Example 2

[0163] Component A of the potting silicone rubber is the same as in Example 11;

[0164] Component B of the potting silicone rubber, by weight percentage, includes: 4 × 10⁻⁶ at 25°C. 5 The composition of the product is as follows: 80 parts of vinyl-terminated poly(dimethylsiloxane) with cps viscosity (vinyl content 0.24 wt%), 550 parts of aminopropyltriethoxysilane surface-modified Al2O3 filler prepared in Example 2, 15 parts of methyl-terminated poly(methylhydro-co-dimethylsiloxane) (hydrogen content 1.6 wt%), and 1.0 part of the inhibitor 3-methyl-1-pentyn-3-ol.

[0165] The preparation method of the potting silicone rubber is the same as that in Example 11.

[0166] Comparative Example 3

[0167] Preparation of the compatibilizer: Pentamethylcyclopentasiloxane (D5H) was used as the initial hydrogen-containing ring. The mixture was heated to 88°C under nitrogen protection. Then, 76.1 g (0.4 mol) of vinyltriethoxysilane and 0.25 g of platinum catalyst PT-5000 (platinum-divinyltetramethyldisiloxane complex) were added dropwise to 60.1 g (0.2 mol) of D5H dissolved in 50 mL of toluene. After the addition was completed in 0.5 hours, the reaction mixture was kept at this temperature for 1 hour. FTIR analysis showed the reaction mixture was within the range of 1640-1660 cm⁻¹. -1 The absorption peak of the C=C double bond disappeared. 20g of activated carbon was added in batches to adsorb the platinum catalyst in the reaction mixture. The catalyst was removed by filtration, and the solvent was removed by vacuum distillation of the filtrate to obtain the compatibilizer.

[0168] Comparative Example 4

[0169] Component A of the potting silicone rubber is the same as in Example 11;

[0170] Component B of the potting silicone rubber, by weight percentage, includes: 4 × 10⁻⁶ at 25°C. 5 The following ingredients were used: 80 parts of vinyl-terminated poly(dimethylsiloxane) with cps viscosity (vinyl content 0.24 wt%), 600 parts of aminopropyltriethoxysilane surface-modified Al2O3 filler prepared in Example 1, 15 parts of methyl-terminated poly(methylhydro-co-dimethylsiloxane) (hydrogen content 1.6 wt%), 24 parts of compatibilizer prepared in Comparative Example 3, and 1.0 part of inhibitor 3-methyl-1-pentyn-3-ol.

[0171] The preparation method of the potting silicone rubber is the same as that in Example 11.

[0172] Comparative Example 5

[0173] Preparation of the compatibilizer: Pentamethylcyclopentasiloxane (D5H) was used as the initial hydrogen-containing ring. The mixture was heated to 88°C under nitrogen protection. Then, 42.8 g (0.2 mol) of ethyl acetoacetate methacrylate (AAEM), 22.8 g (0.2 mol) of allyl glycidyl ether, 0.45 g of polymerization inhibitor p-hydroxyanisole, and 0.3 g of platinum catalyst PT-5000 (platinum-divinyltetramethyldisiloxane complex) were added dropwise to 60.1 g (0.2 mol) of D5H dissolved in 50 mL of toluene. After 0.5 hours of dropwise addition, the reaction mixture was kept at this temperature for 1 hour. FTIR analysis showed that the reaction mixture was within the range of 1640-1660 cm⁻¹. -1 The absorption peak at the C=C double bond disappeared. 25g of activated carbon was added in batches to adsorb the platinum catalyst in the reaction mixture. The catalyst was removed by filtration, and the solvent was removed by vacuum distillation of the filtrate to obtain the compatibilizer.

[0174] Comparative Example 6

[0175] Component A of the potting silicone rubber is the same as in Example 11;

[0176] Component B of the potting silicone rubber, by weight percentage, includes: 4 × 10⁻⁶ at 25°C. 5 The following components were prepared: 80 parts of vinyl-terminated poly(dimethylsiloxane) with a viscosity of cps (vinyl content 0.24 wt%), 600 parts of aminopropyltriethoxysilane surface-modified Al2O3 filler prepared in Example 1, 15 parts of methyl-terminated poly(methylhydro-co-dimethylsiloxane) (hydrogen content 1.6 wt%), 24 parts of compatibilizer prepared in Comparative Example 5, and 1.0 part of inhibitor 3-methyl-1-pentyn-3-ol.

[0177] The preparation method of the potting silicone rubber is the same as that in Example 11.

[0178] The potting silicone rubber mixing and curing operation steps of Examples 11-18, Comparative Examples 1-2, Comparative Examples 4, and Comparative Examples 6 above are as follows:

[0179] S1. Use a mechanical stirrer at 500 rpm to mix components A and B evenly, and continue stirring for 10 minutes until the mixture is uniform in color and free of obvious particles or streaks.

[0180] S2. Transfer the mixed adhesive into a vacuum chamber, turn on the vacuum pump, control the vacuum degree to ≤-0.095MPa, and degas for 15 minutes;

[0181] S3. Quickly inject the vacuum-degassed adhesive into the mold for sealing;

[0182] S4. Place the potted sample into an oven, heat it to 80℃ and keep it at this temperature for 2 hours, then heat it to 110℃ and keep it at this temperature for 2 hours. During the heating process, control the heating rate to not exceed 10℃ / min to avoid the rapid heating causing the air bubbles inside the adhesive to expand and burst, forming pores.

[0183] S5. After the heat preservation time is reached, allow it to cool naturally to room temperature, and demold to obtain the potted silicone rubber cured sample.

[0184] Test section

[0185] Viscosity test: The shear viscosity of the mixed adhesive of components A and B was tested at room temperature using an NDJ-97 rotational viscometer with rotor No. 4 selected.

[0186] Thermal conductivity test: The thermal conductivity of the potted silicone rubber cured product was tested using a TPS-2500S thermal analyzer.

[0187] Coefficient of linear expansion (CLTE) test: The thermal expansion characteristics of potted silicone rubber cured samples were tested in the range of 25-250℃ using a thermomechanical analyzer (heating rate 10℃ / min);

[0188] Adhesion performance testing: Tensile lap shear strength tests were conducted using a universal testing machine to evaluate the adhesion performance between the potted silicone rubber and the rigid printed circuit board. The rigid printed circuit board substrate was first ultrasonically cleaned with isopropanol for 10 minutes at room temperature, then dried at 60°C for 2 hours. Two-component liquid silicone rubber was potted into a customized gap between the two substrates and cured under pressure-free conditions following a series of steps: 80°C × 2 hours + 110°C × 2 hours. After being left at room temperature for 24 hours, the lap shear strength test was performed, and the effective adhesive area was 625 mm². 2 (25mm×25mm), record the maximum tensile force of the tensile testing machine and the failure mode of the lap joint interface, and calculate the lap shear strength based on the maximum tensile force.

[0189] The test results of Examples 11-18, Comparative Examples 1-2, Comparative Examples 4, and Comparative Examples 6 are listed in Table 1.

[0190] XPS and thermogravimetric analysis results of aminosilane coupling agent-modified Al2O3 and unmodified Al2O3 in Examples 1-2 are listed below. Figure 1-2 This indicates that the aminosilane coupling agent was successfully grafted onto the Al2O3 surface. TG testing (heating rate 25℃ / min, heating range from room temperature to 700℃, atmosphere: air) revealed that the modified Al2O3 grafted with this agent exhibited a lower thermogravimetric residual rate at 700℃ compared to the unmodified Al2O3, further confirming the organic side linking to the Al2O3 surface.

[0191] Table 1

[0192]

[0193] Analysis of the data in Table 1 shows that in Examples 11-18, Al2O3 modified with aminosilane coupling agents was chemically bonded using compatibilizers containing epoxy or acetoacetic acid groups to siloxane and silane groups. Subsequently, after mixing the AB components, the Si-H bonds in the compatibilizer underwent a hydrosilylation reaction with vinyl groups to obtain a cured silicone rubber. Overall, the AB two-component potting silicone rubber prepared in Examples 11-18 has a high Al2O3 filling content of approximately 80 wt%, and the AB components exhibit low viscosity and easy flow after mixing, facilitating potting and vacuum degassing. The corresponding cured product possesses advantages such as high thermal conductivity and low expansion. Furthermore, the compatibilizer also acts as a tackifier, and the cured silicone rubber exhibits good adhesion to rigid printed circuit board (PCB) materials, with an overlap shear strength of not less than 0.87 MPa, meeting the potting requirements of high-power inductors.

[0194] The compatibilizer reacts with the amino groups on the surface of Al2O3 through epoxy groups or acetoacetic acid groups, and forms aggregates with fine pores by tightly binding Al2O3 particles through chemical bonds. During the mixing and mechanical stirring of component B and component A, the high-viscosity vinyl polydimethylsiloxane fills the pores through capillary action, reducing the frictional interaction between particles, thereby reducing the overall viscosity of the mixed adhesive.

[0195] A comparison of the data from Examples 11-18 shows that Examples 13-15, using the epoxy-containing compatibilizers prepared in Examples 5-7, achieved a better effect in reducing the viscosity of the AB component mixture. This may be because the epoxy groups react with the amino groups to form new hydroxyl groups, which can then further condense with the alkoxy groups of the silane coupling agent, forming more dense aggregates and resulting in better viscosity reduction. For similar reasons, the cured silicone rubber products of Examples 13-15 have relatively higher thermal conductivity and relatively lower CLTE.

[0196] Figure 3 The infrared spectra of the compatibilizer prepared in Example 7 were compared with those of the three raw materials (D5H, vinyltriethoxysilane and allyl glycidyl ether), which confirmed the presence of Si-OCH2CH3, Si-H and epoxy groups in the compatibilizer, while the corresponding vinyl groups disappeared as the hydrosilylation reaction proceeded.

[0197] In Comparative Example 1, component B did not use an amino-containing coupling agent to modify the surface of Al2O3 filler. The compatibilizer alone could not form enough chemical bonds with the Al2O3 surface, and could not form the corresponding agglomerates, resulting in poor viscosity reduction and thermal conductivity.

[0198] In Comparative Example 2, no compatibilizer was used. The amino groups in the Al2O3 modified by the aminosilane coupling agent came into direct contact with the platinum catalyst, resulting in catalyst poisoning and failure to cure the silicone rubber.

[0199] The reason for using Comparative Example 4 is similar to that of Comparative Example 2. The compatibilizer prepared in Comparative Example 3 was used. The compatibilizer did not introduce epoxy groups or acetoacetic acid groups, making it difficult to perform end-capping reaction on the surface amino groups in the modified Al2O3. After the amino groups came into contact with the platinum catalyst, the catalyst was poisoned and the silicone rubber could not be cured.

[0200] Comparative Example 6 used the compatibilizer prepared in Comparative Example 5, but did not use vinyl silane coupling agent to graft hydrogen-containing silane cyclic compounds. The amino groups on the surface of Al2O3 modified by amino silane coupling agent are relatively limited. It is difficult to form tightly bound Al2O3 aggregates by relying solely on the cross-linking reaction between epoxy groups or acetoacetic acid groups and amino groups, resulting in poor viscosity reduction and thermal conductivity.

[0201] Finally, it should be noted that the above-described embodiments are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the patent application. It should be pointed out that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. Furthermore, it should be understood that after reading the above teachings of this application, those skilled in the art can make various alterations or modifications to this application, and the equivalent forms obtained also fall within the scope of protection of this application. It should also be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A compatibilizer, characterized in that, Its molecular structure includes a polysiloxane core and side arms containing substituents, with the general structural formula as follows: Where a, b, and c are positive integers greater than or equal to 1, and (a+b+c)≥3; R1 is selected from methyl, ethyl, or phenyl; R2 contains one or both of the epoxy group and the acetoacetate group; R3, R4, and R5 may be the same or different, and at least one of them is selected from hydrolyzable alkoxy groups, including methoxy, ethoxy, or isopropoxy.

2. A method for preparing the compatibilizer as described in claim 1, characterized in that, The compatibilizer is prepared by hydrosilylation reaction of hydrogen-containing silane cyclic material with an active monomer containing unsaturated bonds and a vinyl silane coupling agent. The hydrogen-containing silane cyclic body is selected from one of tetramethylcyclotetrasiloxane or pentamethylcyclopentasiloxane; The active monomer containing unsaturated bonds is selected from one or a combination of two of ethyl methacrylate acetoacetate and allyl glycidyl ether; The vinyl silane coupling agent is selected from one of vinyltrimethoxysilane, vinyltriethoxysilane, or vinyltriisopropoxysilane.

3. The method for preparing the compatibilizer according to claim 2, characterized in that, The preparation method specifically includes the following steps: S1. Hydrosilylation reaction of hydrogen-containing silane cyclic compounds with monomers containing unsaturated bonds is carried out using a platinum catalyst at 80-110℃ to obtain the hydrosilylation product. S2. The hydrosilylation product obtained in step S1 is subjected to a hydrosilylation reaction with a vinylsilane coupling agent in the presence of a platinum catalyst at 80-110°C to obtain the hydrosilylation product. S3. The hydrosilylation product obtained in step S2 is post-processed, including using an adsorbent to remove residual platinum catalyst, and filtration to obtain the compatibilizer. The free radical polymerization inhibitor is selected from phenolic polymerization inhibitors; The platinum catalysts in steps S1 and S2 are selected from one or more combinations of platinum-isopropanol complex catalysts, platinum-ene complex catalysts, platinum-phosphine amine complex catalysts, and platinum-(N-heterocyclic carbene) complexes. The monomer containing unsaturated bonds in step S1 is selected from ethyl acetoacetate methacrylate and / or allyl glycidyl ether; The adsorbent in step S3 is selected from activated carbon.

4. The use of the compatibilizer as described in claim 1 in the preparation of potting silicone rubber.

5. A potting silicone rubber, characterized in that, It includes component A and component B, wherein component A includes: vinyl-terminated poly(dimethylsiloxane), methyl-terminated poly(dimethyl-co-methylvinylsiloxane), thermally conductive filler and platinum catalyst; Component B comprises: vinyl-terminated poly(dimethylsiloxane), aminosilane coupling agent modified thermally conductive filler, methyl-terminated poly(methylhydro-co-dimethylsiloxane), inhibitor, and compatibilizer as described in claim 1; The vinyl content of the vinyl-terminated poly(dimethylsiloxane) is 0.1-0.4 wt%. The vinyl content of the methyl-terminated poly(dimethyl-co-methylvinylsiloxane) is 0.1-0.4 wt%. The hydrogen content of the methyl-terminated poly(methylhydro-co-dimethylsiloxane) is 0.1-2 wt%. The aminosilane coupling agent contains at least one primary amino group and at least one hydrolyzable Si-OR group, wherein R is selected from methyl, ethyl or isopropyl. The thermally conductive filler is selected from Al2O3; The platinum catalyst is selected from platinum-olefin complex catalysts; The inhibitor is selected from alkynols and their derivatives.

6. The potting silicone rubber according to claim 5, characterized in that, The platinum-olefin complex catalyst is selected from platinum-divinyltetramethyldisiloxane complex; And / or, the aminosilane coupling agent is selected from any one or more of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldimethoxymethylsilane, 3-aminopropyldiethoxymethylsilane, 3-aminopropylmethoxydimethylsilane, 3-aminopropylethoxydimethylsilane, N-aminoethyl-3-aminopropyltrimethoxysilane, N-aminoethyl-3-aminopropyltriethoxysilane, N-aminoethyl-3-aminopropylmethyldimethoxysilane, and N-aminoethyl-3-aminopropylmethyldiethoxysilane; And / or, the inhibitor is selected from one of methylbutynol, dimethylethynol, vinylcyclohexanol, 3-methyl-1-pentyn-3-ol or 3,5-dimethyl-1-hexyn-3-ol.

7. The potting silicone rubber according to claim 5, characterized in that, The specific method for modifying the thermally conductive filler with the aminosilane coupling agent includes: S1. Add the aminosilane coupling agent to a mixed solution of water and ethanol for hydrolysis to obtain a hydrolysate; S2. Heat the thermally conductive filler to 100-120℃ and spray the hydrolysate prepared in step S1 onto it under mechanical stirring to perform surface modification. S3. Wash the surface-modified thermally conductive filler with ethanol to remove unreacted free silane coupling agent. S4. Dry the surface-modified thermally conductive filler.

8. The potting silicone rubber according to claim 5, characterized in that, The A component of the potting silicone rubber, by weight percentage, comprises: 80-100 parts of vinyl-terminated poly(dimethylsiloxane), 20-40 parts of methyl-terminated poly(dimethyl-co-methylvinylsiloxane), 180-220 parts of thermally conductive filler, and 0.5-2.0 parts of platinum catalyst. Component B of the potting silicone rubber, by weight percentage, comprises: 60-100 parts of vinyl-terminated poly(dimethylsiloxane), 500-700 parts of aminosilane coupling agent modified thermally conductive filler, 10-40 parts of methyl-terminated poly(methylhydro-co-dimethylsiloxane), 20-50 parts of compatibilizer, and 0.5-2.0 parts of inhibitor. Furthermore, the preparation method of the potting silicone rubber described above includes: The preparation method of component A is to mechanically mix the prescribed amounts of vinyl-terminated polydimethylsiloxane, methyl-terminated poly(dimethyl-co-methylvinylsiloxane) and thermally conductive filler, and then mechanically mix them with the prescribed amounts of platinum catalyst. The preparation method of component B is as follows: the formulated amount of aminosilane coupling agent modified thermally conductive filler and compatibilizer are mechanically mixed, then mechanically mixed with vinyl-terminated polydimethylsiloxane, and finally mechanically mixed with the formulated amount of hydrogen-containing silicone oil and inhibitor. Preferably, a planetary mixer is used to mechanically mix the different materials during the preparation of components A and B.

9. A potting silicone rubber cured product, characterized in that, The potting silicone rubber according to any one of claims 5-8 is obtained by heat vulcanization; Preferably, the thermal conductivity of the potted silicone rubber cured material is not less than 2.6 W·m. -1 ·K -1 The coefficient of linear expansion is not higher than 75ppm / ℃, and the lap shear strength of the PCB board is not lower than 0.8MPa.

10. The application of the potting silicone rubber cured compound as described in claim 9 in high-power inductor devices.

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