Voltage breakdown resistant heat-conducting insulating spacer

Abstract

The invention provides a voltage breakdown resistant heat-conducting insulating spacer. The spacer is prepared from the following materials in parts by weight: 100-120 parts of methyl vinyl silicone rubber, 12-18 parts of hydrogen-containing silicone oil, 28-32 parts of white carbon black, 45-65 parts of modified aluminum nitride powder, 10-14 parts of polymethyl methacrylate coated magnesium oxide whiskers, 0.3-0.5 part of a curing agent and 1-2 parts of a peroxide vulcanizing agent, the preparation method comprises the following steps: weighing the raw materials in proportion, and stirring and uniformly mixing the methyl vinyl silicone rubber, the white carbon black, the modified aluminum nitride powder and the polymethyl methacrylate coated magnesium oxide whisker to obtain a prepared material; and adding hydrogen-containing silicone oil, a curing agent and a peroxide vulcanizing agent into the prepared material, uniformly stirring, and vulcanizing at 75-85 DEG C to obtain the product. According to the voltage-breakdown-resistant heat-conducting insulating spacer, the voltage-breakdown-resistant capability of the heat-conducting insulating spacer is improved by blending the raw materials and the proportion.

Description

Technical Field

[0001] The present invention relates to the technical field of insulating gaskets, and particularly to a heat-conducting insulating gasket with voltage breakdown resistance. Background Art

[0002] With the rapid development of electronic and electrical technologies, especially in complex application fields such as high voltage, high frequency, and high power, the performance requirements for heat-conducting insulating materials by electronic and electrical equipment are becoming increasingly stringent. As a key component in the thermal management systems of these devices, the heat-conducting insulating gasket not only needs to have efficient heat-conducting performance to achieve effective heat transfer, but also needs to have excellent insulating performance and voltage breakdown resistance to ensure the safe and stable operation of the device in a complex working environment.

[0003] Traditional heat-conducting insulating gaskets have certain performance in heat conduction and insulation, but in a high-voltage environment, their voltage breakdown resistance often fails to meet the actual requirements. This is mainly because the interfacial interaction between the filler and the substrate is weak, resulting in charge accumulation, discharge, and even breakdown phenomena under high-voltage conditions, thereby causing device damage or failure. Such deficiencies in performance not only affect the stability and reliability of the device, but also increase potential safety hazards.

[0004] Therefore, developing a heat-conducting insulating gasket that can maintain stable and reliable voltage breakdown resistance in a high-voltage environment has become an urgent problem to be solved in the current field of electronic and electrical technologies. This new type of heat-conducting insulating gasket needs to further improve its voltage breakdown resistance on the basis of ensuring efficient heat conduction and good insulating performance to meet the requirements of modern electronic and electrical equipment for high-performance heat-conducting insulating materials. Based on this, the present invention provides a heat-conducting insulating gasket with voltage breakdown resistance. Summary of the Invention

[0005] The purpose of the present invention is to provide a heat-conducting insulating gasket with voltage breakdown resistance, which not only improves the adhesion performance and dispersibility between the filler and the substrate, but also enhances the voltage breakdown resistance of the heat-conducting insulating gasket, making it more suitable for the high-voltage and high-demand electronic and electrical fields.

[0006] On the one hand, the present invention provides a heat-conducting insulating gasket with voltage breakdown resistance, which comprises the following materials in parts by weight: 100 - 120 parts of methyl vinyl silicone rubber, 12 - 18 parts of hydrogen-containing silicone oil, 28 - 32 parts of fumed silica, 45 - 65 parts of modified aluminum nitride powder, 10 - 14 parts of polymethyl methacrylate-coated magnesium oxide whiskers, 0.3 - 0.5 parts of curing agent, and 1 - 2 parts of peroxide vulcanizing agent.

[0007] Further, the volatile content of the hydrogen-containing silicone oil ≤ 300 ppm, and its hydrogen content is 0.16 - 0.22%.

[0008] Furthermore, the preparation method of the modified aluminum nitride powder includes: adding a silane coupling agent and a titanate coupling agent into an organic solvent, stirring for dissolution to obtain a mixed solution, adding 105-115 parts of aluminum nitride powder into the mixed solution, stirring evenly, placing it in a water bath at 65-75 °C and stirring for 6-8 h. After the solvent has evaporated completely, drying it at 60-80 °C for 12-16 h, and then drying it at 120-140 °C for 1-2 h to obtain the product.

[0009] As a high-performance filler, aluminum nitride powder has excellent thermal conductivity and insulation properties in thermal conductive insulation gaskets. However, its surface properties may directly affect the interfacial interaction between the filler and the resin substrate, thereby affecting the overall performance of the composite material.

[0010] Through its unique reaction mechanism, the silane coupling agent can form stable chemical bonds on the surface of aluminum nitride powder. These chemical bonds not only firmly fix the filler on the substrate surface but also form a protective film. This protective film can effectively isolate the erosion of the external environment on the filler, such as moisture, oxygen, and other corrosive substances, thereby maintaining the stability and integrity of the filler. At the same time, this protective film can also improve the adhesion performance between the filler and the substrate. When an electric field is formed inside the thermal conductive insulation gasket, strong adhesion performance can ensure that the filler will not move or fall off due to the action of the electric field force, thereby maintaining the stability and continuity of the composite material.

[0011] The titanate coupling agent plays a role by improving the dispersibility and durability between the filler and the resin. It can make the aluminum nitride powder disperse more evenly in the resin substrate, reducing the agglomeration phenomenon between the fillers. This uniform dispersibility can not only improve the thermal conductivity of the composite material but also reduce the local electric field concentration caused by uneven filler distribution, thereby reducing the risk of voltage breakdown. In addition, the titanate coupling agent can also enhance the durability between the filler and the resin. During long-term use, the interface between the filler and the resin may be affected by various factors such as heat, humidity, and mechanical stress and undergo aging or damage. The titanate coupling agent can delay this aging or damage process by enhancing the interfacial interaction, thereby maintaining the long-term stability of the composite material.

[0012] Furthermore, the aluminum nitride powder includes aluminum nitride powders with diameters of 1-3 μm and 14-16 μm in a weight ratio of 1:(1-2).

[0013] Aluminum nitride itself has good electrical insulation properties. Therefore, by optimizing the packing structure of the thermal conductive filler, the electric field concentration phenomenon caused by too long thermal conduction chains or uneven packing can be reduced. In the thermal conductive insulation gasket with a mixed packing of large and small particles, since the thermal conduction paths are more dense and uniform, the electric field distribution is also more uniform, which greatly reduces the risk of voltage breakdown caused by too high local electric field.

[0014] Furthermore, the dosage ratio of the silane coupling agent, titanate coupling agent, organic solvent, and aluminum nitride powder is (6-10):(6-10):(20-24):(105-115).

[0015] Furthermore, the organic solvent is a mixed solution of ethanol and acetone with a volume ratio of 1:1.

[0016] Furthermore, the preparation method of the polymethyl methacrylate-coated magnesium oxide whiskers includes: uniformly mixing 100 parts of magnesium oxide whiskers, 3-5 parts of methyl methacrylate monomer, and 0.5-0.9 parts of azobisisobutyronitrile, and then performing microwave polymerization to obtain the product.

[0017] Furthermore, the parameters of the microwave polymerization are: frequency 85-95 GHz, temperature 75-85 °C, and time 30-60 min.

[0018] Furthermore, the curing agent includes di-tert-butyl peroxide and vinyltriamine with a weight ratio of 1:1; the peroxide vulcanizing agent is DBPMH.

[0019] On the other hand, the present invention also provides a preparation method of a voltage-resistant thermal conductive insulating gasket, and the steps include: weighing raw materials in proportion, stirring methyl vinyl silicone rubber, white carbon black, modified aluminum nitride powder, and polymethyl methacrylate-coated magnesium oxide whiskers until evenly mixed to obtain a preliminary material; adding hydrogen-containing silicone oil, curing agent, and peroxide vulcanizing agent to the preliminary material and stirring evenly, and then performing vulcanization at 75-85 °C to obtain the product.

[0020] The beneficial effects of the present invention are as follows: Titanate coupling agents are mainly used to improve the dispersibility and durability between fillers and resins; silane coupling agents are mainly used to form chemical bonds on the surface of fillers, firmly fix the fillers on the surface of the substrate, and form a protective film. This protective film can effectively protect the fillers from external factors, and at the same time improve the adhesion performance between the fillers and the substrate. The enhancement of this adhesion performance helps to improve the overall strength and stability of the composite material. In the present invention, silane coupling agents and titanate coupling agents are used to synergistically modify aluminum nitride powder. The present invention effectively enhances the dispersibility and durability between the fillers and the resins, and at the same time uses silane coupling agents to form chemical bonds on the surface of the fillers, firmly fix the fillers and generate a protective film. This protective film can not only effectively isolate the damage of external factors such as moisture, oxygen and chemical substances to the fillers, but also significantly enhance the adhesion performance between the fillers and the substrate. The enhancement of this adhesion performance directly reduces the charge accumulation and discharge phenomena at the interface, thereby greatly improving the voltage breakdown resistance of the thermal conductive insulating gasket. The coordinated action of silane coupling agents and titanate coupling agents not only realizes the comprehensive modification treatment of the filler surface, but also significantly enhances the overall strength and stability of the thermal conductive insulating gasket. The tight connection between the filler and the substrate and the improvement of the interface stability enable the thermal conductive insulating gasket to maintain stable operation for a longer time under high-voltage environments, reducing the failure risk caused by voltage breakdown. In addition, the dispersibility of the modified aluminum nitride filler in the thermal conductive insulating gasket is improved, which helps to form a more uniform and efficient heat conduction channel, thereby improving the thermal conductivity of the thermal conductive insulating gasket. This is crucial for the heat dissipation performance of high-heat load devices such as electronic and electrical appliances, and helps to extend the service life and stability of the devices.

[0021] The present invention selects aluminum nitride powders with two different diameters as raw materials. The mixed use of aluminum nitride powders with different diameters in the thermal conductive insulating gasket can effectively form a multi-scale thermal conductive network. Due to their larger sizes, the large particles (14 - 16 μm) can form the main thermal conductive chains, while the small particles (1 - 3 μm) can fill the gaps between the large particles to form a more compact packing. This mixed packing of large and small particles not only increases the volume fraction of the thermal conductive filler but also forms more inter-particle contact points, thus increasing the number of thermal conductive paths. The increase in thermal conductive paths directly affects the thermal conductivity of the thermal conductive insulating gasket. Since aluminum nitride itself has a high thermal conductivity, this multi-scale thermal conductive network can significantly improve the heat conduction efficiency of the gasket. When heat is transferred in the insulating gasket, it can be exported more quickly and effectively, thereby reducing the possibility of local high temperature and the risk of material aging or failure caused by high temperature. In addition, the voltage breakdown resistance characteristic of the aluminum nitride powder is also of great significance for its application in the thermal conductive insulating gasket. As an inorganic filler, aluminum nitride has excellent electrical insulation properties. Its high resistivity can effectively prevent current leakage, thus improving the voltage breakdown resistance ability of the insulating gasket. When using a mixture of large and small particle aluminum nitride powders, due to the increase in thermal conductive paths, the electric field distribution becomes more uniform, reducing the phenomenon of excessive local electric field intensity and further improving the voltage breakdown resistance characteristic of the insulating gasket.

[0022] The present invention mixes methyl methacrylate monomer and initiator with magnesium oxide whiskers, enabling methyl methacrylate to be evenly distributed inside and on the outer surface of the micropores of the magnesium oxide whiskers. Then, through a polymerization reaction, methyl methacrylate is converted into poly(methyl methacrylate) (PMMA). This process not only achieves the coating of the inner and outer surfaces of the magnesium oxide whiskers by PMMA but also enhances the interfacial bonding force between the two. The application of this composite structure of poly(methyl methacrylate)-coated magnesium oxide whiskers in the thermal conductive insulating gasket brings significant advantages. First, the coating layer of PMMA effectively isolates the direct contact between the magnesium oxide whiskers and the external environment, reducing the conductance paths and thus improving the electrical insulation performance of the material. Second, due to the tight bonding between PMMA and the magnesium oxide whiskers, the thermal conductivity of the material is maintained and may even be improved due to the optimization of the interface. In addition, the composite structure of poly(methyl methacrylate)-coated magnesium oxide whiskers significantly improves the voltage breakdown resistance characteristic of the thermal conductive insulating gasket. Under a high-voltage electric field, the coating layer can effectively prevent the occurrence of electric breakdown, ensuring the stability and reliability of the material. This is of great significance for improving the operating safety and extending the service life of electronic devices. Detailed implementation manners

[0023] The technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the scope of protection of the present invention. It should be noted that the following raw materials are all commercially available.

[0024] Example 1 This example provides a heat-conducting and insulating gasket resistant to voltage breakdown, which comprises the following materials in parts by weight: 110 parts of methyl vinyl silicone rubber, 15 parts of hydrogen-containing silicone oil, 30 parts of white carbon black, 55 parts of modified aluminum nitride powder, 12 parts of magnesium oxide whiskers coated with polymethyl methacrylate, 0.4 part of curing agent, and 1.5 parts of peroxide vulcanizing agent; Among them, the volatile content of the hydrogen-containing silicone oil ≤ 300 ppm, and its hydrogen content is 0.19%; the curing agent includes di-tert-butyl peroxide and vinyltriamine with a weight ratio of 1:1; the peroxide vulcanizing agent is DBPMH; The preparation method of the modified aluminum nitride powder includes: adding 8 parts of silane coupling agent and 8 parts of titanate coupling agent to a mixed solution of 22 parts of ethanol and acetone with a volume ratio of 1:1, stirring and dissolving to obtain a mixed solution, adding 110 parts of aluminum nitride powder to the mixed solution, stirring evenly, placing it in a water bath at 70 °C and stirring for 7 h, waiting for the solvent to evaporate completely, drying at 70 °C for 14 h, and then drying at 130 °C for 1.5 h to obtain; Among them, the silane coupling agent is vinyltrimethoxysilane, and the titanate coupling agent is diisopropyl bis(triethanolamine) titanate. Unless otherwise specified, the same applies to the following examples and comparative examples.

[0025] The aluminum nitride powder includes aluminum nitride powders with diameters of 2 μm and 15 μm respectively with a weight ratio of 1:1.5; The preparation method of the magnesium oxide whiskers coated with polymethyl methacrylate includes: mixing 100 parts of magnesium oxide whiskers, 4 parts of methyl methacrylate monomer and 0.7 part of azobisisobutyronitrile evenly and then carrying out microwave polymerization to obtain; the parameters of the microwave polymerization are: frequency 90 GHz, temperature 80 °C, time 45 min; The preparation method of a heat-conducting and insulating gasket resistant to voltage breakdown in this example includes the steps of: weighing the raw materials according to the ratio, stirring methyl vinyl silicone rubber, white carbon black, modified aluminum nitride powder, and magnesium oxide whiskers coated with polymethyl methacrylate until evenly mixed to obtain a preliminary material; adding hydrogen-containing silicone oil, curing agent and peroxide vulcanizing agent to the preliminary material, stirring evenly, and carrying out vulcanization at 80 °C to obtain.

[0026] Example 2 This embodiment provides a voltage-resistant and heat-conducting insulating gasket, which comprises the following materials in parts by weight: 115 parts of methyl vinyl silicone rubber, 16 parts of hydrogen-containing silicone oil, 29 parts of white carbon black, 50 parts of modified aluminum nitride powder, 11 parts of magnesium oxide whiskers coated with polymethyl methacrylate, 0.3 part of curing agent, and 1 part of peroxide vulcanizing agent; Among them, the volatile content of the hydrogen-containing silicone oil ≤ 300 ppm, and its hydrogen content is 0.2%; the curing agent includes di-tert-butyl peroxide and vinyltriamine with a weight ratio of 1:1; the peroxide vulcanizing agent is DBPMH; The preparation method of the modified aluminum nitride powder includes: adding 9 parts of silane coupling agent and 9 parts of titanate coupling agent to a mixed solution of 20 parts of ethanol and acetone with a volume ratio of 1:1, stirring for dissolution to obtain a mixed solution, adding 110 parts of aluminum nitride powder to the mixed solution, stirring evenly, placing it in a water bath at 65 °C and stirring for 8 h. After the solvent has evaporated completely, drying at 60 °C for 16 h, and then drying at 120 °C for 2 h to obtain; The aluminum nitride powder includes aluminum nitride powders with diameters of 1 μm and 14 μm respectively with a weight ratio of 1:1; The preparation method of the magnesium oxide whiskers coated with polymethyl methacrylate includes: mixing 100 parts of magnesium oxide whiskers, 3 parts of methyl methacrylate monomer and 0.5 part of azobisisobutyronitrile evenly and then carrying out microwave polymerization to obtain; the parameters of the microwave polymerization are: frequency 85 GHz, temperature 75 °C, time 30 min; The preparation method of a voltage-resistant and heat-conducting insulating gasket in this embodiment includes the steps of: weighing raw materials in proportion, stirring methyl vinyl silicone rubber, white carbon black, modified aluminum nitride powder, and magnesium oxide whiskers coated with polymethyl methacrylate until evenly mixed to obtain a preliminary material; adding hydrogen-containing silicone oil, curing agent and peroxide vulcanizing agent to the preliminary material, stirring evenly, and carrying out vulcanization at 75 °C to obtain.

[0027] Example 3 This embodiment provides a voltage-resistant and heat-conducting insulating gasket, which comprises the following materials in parts by weight: 105 parts of methyl vinyl silicone rubber, 15 parts of hydrogen-containing silicone oil, 32 parts of white carbon black, 60 parts of modified aluminum nitride powder, 13 parts of magnesium oxide whiskers coated with polymethyl methacrylate, 0.5 part of curing agent, and 2 parts of peroxide vulcanizing agent; Among them, the volatile content of the hydrogen-containing silicone oil ≤ 300 ppm, and its hydrogen content is 0.22%; the curing agent includes di-tert-butyl peroxide and vinyltriamine with a weight ratio of 1:1; the peroxide vulcanizing agent is DBPMH; The preparation method of the modified aluminum nitride powder comprises: adding 10 parts of silane coupling agent and 10 parts of titanate coupling agent into 24 parts of a mixed solution of ethanol and acetone with a volume ratio of 1:1, stirring and dissolving to obtain a mixed solution, adding 115 parts of aluminum nitride powder into the mixed solution, stirring evenly, placing it in a water bath at 75°C and stirring for 8 h, waiting for the solvent to evaporate completely, drying at 80°C for 12 h, and then drying at 140°C for 1 h to obtain the product; The aluminum nitride powder comprises aluminum nitride powders with diameters of 3 μm and 16 μm respectively, and the weight ratio is 1:2; The preparation method of the polymethyl methacrylate-coated magnesium oxide whiskers comprises: mixing 100 parts of magnesium oxide whiskers, 5 parts of methyl methacrylate monomer and 0.9 part of azobisisobutyronitrile evenly, and then carrying out microwave polymerization to obtain the product; the parameters of the microwave polymerization are: frequency 95 GHz, temperature 75°C, and time 60 min; In this embodiment, the preparation method of a voltage-resistant thermal insulation gasket comprises the steps of: weighing raw materials in proportion, stirring methyl vinyl silicone rubber, white carbon black, modified aluminum nitride powder, and polymethyl methacrylate-coated magnesium oxide whiskers until evenly mixed to obtain a preliminary material; adding hydrogen-containing silicone oil, curing agent, and peroxide vulcanizing agent to the preliminary material, stirring evenly, and carrying out vulcanization at 85°C to obtain the product.

[0028] Example 4 This embodiment provides a voltage-resistant thermal insulation gasket, which contains the following materials in parts by weight: 100 parts of methyl vinyl silicone rubber, 18 parts of hydrogen-containing silicone oil, 28 parts of white carbon black, 45 parts of modified aluminum nitride powder, 14 parts of polymethyl methacrylate-coated magnesium oxide whiskers, 0.3 part of curing agent, and 1 part of peroxide vulcanizing agent; Among them, the volatile content of the hydrogen-containing silicone oil ≤ 300 ppm, and its hydrogen content is 0.2%; the curing agent comprises 1:1 by weight of di-tert-butyl peroxide and vinyltriamine; the peroxide vulcanizing agent is DBPMH; The preparation method of the modified aluminum nitride powder comprises: adding 10 parts of silane coupling agent and 6 parts of titanate coupling agent into 24 parts of a mixed solution of ethanol and acetone with a volume ratio of 1:1, stirring and dissolving to obtain a mixed solution, adding 115 parts of aluminum nitride powder into the mixed solution, stirring evenly, placing it in a water bath at 65°C and stirring for 8 h, waiting for the solvent to evaporate completely, drying at 80°C for 12 h, and then drying at 140°C for 1 h to obtain the product; The aluminum nitride powder comprises aluminum nitride powders with diameters of 1 μm and 16 μm respectively, and the weight ratio is 1:1; The preparation method of the polymethyl methacrylate-coated magnesium oxide whiskers comprises: uniformly mixing 100 parts of magnesium oxide whiskers, 5 parts of methyl methacrylate monomer and 0.9 part of azobisisobutyronitrile, and then carrying out microwave polymerization to obtain the product; the parameters of the microwave polymerization are: frequency 95 GHz, temperature 85 °C, time 30 min; In this embodiment, a preparation method of a voltage-resistant and heat-conducting insulating gasket comprises the steps of: weighing raw materials in proportion, stirring methyl vinyl silicone rubber, white carbon black, modified aluminum nitride powder and polymethyl methacrylate-coated magnesium oxide whiskers until they are uniformly mixed to obtain a preliminary material; adding hydrogen-containing silicone oil, a curing agent and a peroxide vulcanizing agent to the preliminary material, stirring evenly, and carrying out vulcanization at 80 °C to obtain the product.

[0029] Comparative Example 1 This embodiment provides a voltage-resistant and heat-conducting insulating gasket, which comprises the following materials in parts by weight: 110 parts of methyl vinyl silicone rubber, 15 parts of hydrogen-containing silicone oil, 30 parts of white carbon black, 55 parts of modified alumina powder, 12 parts of polymethyl methacrylate-coated magnesium oxide whiskers, 0.4 part of curing agent and 1.5 parts of peroxide vulcanizing agent; Among them, the volatile content of the hydrogen-containing silicone oil ≤ 300 ppm, and its hydrogen content is 0.19%; the curing agent comprises di-tert-butyl peroxide and vinyltriamine with a weight ratio of 1:1; the peroxide vulcanizing agent is DBPMH; The preparation method of the modified alumina powder comprises: adding 8 parts of silane coupling agent and 8 parts of titanate coupling agent to a mixed solution of 22 parts of ethanol and acetone with a volume ratio of 1:1, stirring to dissolve to obtain a mixed solution, adding 110 parts of alumina powder to the mixed solution, stirring evenly, placing it in a water bath at 70 °C and stirring for 7 h, waiting for the solvent to evaporate completely, drying at 70 °C for 14 h, and then drying at 130 °C for 1.5 h to obtain the product; The alumina powder comprises alumina powders with diameters of 2 μm and 15 μm respectively with a weight ratio of 1:1.5; The preparation method of the polymethyl methacrylate-coated magnesium oxide whiskers comprises: uniformly mixing 100 parts of magnesium oxide whiskers, 4 parts of methyl methacrylate monomer and 0.7 part of azobisisobutyronitrile, and then carrying out microwave polymerization to obtain the product; the parameters of the microwave polymerization are: frequency 90 GHz, temperature 80 °C, time 45 min; In this embodiment, a preparation method of a voltage-resistant and heat-conducting insulating gasket comprises the steps of: weighing raw materials in proportion, stirring methyl vinyl silicone rubber, white carbon black, modified alumina powder and polymethyl methacrylate-coated magnesium oxide whiskers until they are uniformly mixed to obtain a preliminary material; adding hydrogen-containing silicone oil, a curing agent and a peroxide vulcanizing agent to the preliminary material, stirring evenly, and carrying out vulcanization at 80 °C to obtain the product.

[0030] Comparative Example 2 This embodiment provides a voltage-resistant and heat-conducting insulating gasket, which comprises the following materials in parts by weight: 110 parts of methyl vinyl silicone rubber, 15 parts of hydrogen-containing silicone oil, 30 parts of white carbon black, 55 parts of modified aluminum nitride powder, 12 parts of poly(methyl methacrylate) coated magnesium oxide whiskers, 0.4 part of curing agent, and 1.5 parts of peroxide vulcanizing agent; Among them, the volatile content of the hydrogen-containing silicone oil ≤ 300 ppm, and its hydrogen content is 0.19%; the curing agent comprises di-tert-butyl peroxide and vinyltriamine with a weight ratio of 1:1; the peroxide vulcanizing agent is DBPMH; The preparation method of the modified aluminum nitride powder includes: adding 16 parts of silane coupling agent to a mixed solution of 22 parts of ethanol and acetone with a volume ratio of 1:1, stirring for dissolution to obtain a mixed solution, adding 110 parts of aluminum nitride powder to the mixed solution, stirring evenly, placing it in a water bath at 70 °C and stirring for 7 h, waiting for the solvent to evaporate completely, drying at 70 °C for 14 h, and then drying at 130 °C for 1.5 h to obtain; The aluminum nitride powder comprises aluminum nitride powders with diameters of 2 μm and 15 μm respectively with a weight ratio of 1:1.5; The preparation method of the poly(methyl methacrylate) coated magnesium oxide whiskers includes: mixing 100 parts of magnesium oxide whiskers, 4 parts of methyl methacrylate monomer and 0.7 part of azobisisobutyronitrile evenly and then carrying out microwave polymerization to obtain; the parameters of the microwave polymerization are: frequency 90 GHz, temperature 80 °C, time 45 min; The preparation method of a voltage-resistant and heat-conducting insulating gasket in this embodiment comprises the steps of: weighing raw materials according to the proportion, stirring methyl vinyl silicone rubber, white carbon black, modified aluminum nitride powder, and poly(methyl methacrylate) coated magnesium oxide whiskers until evenly mixed to obtain a preliminary material; adding hydrogen-containing silicone oil, curing agent, and peroxide vulcanizing agent to the preliminary material, stirring evenly, and carrying out vulcanization at 80 °C to obtain.

[0031] Comparative Example 3 This embodiment provides a voltage-resistant and heat-conducting insulating gasket, which comprises the following materials in parts by weight: 110 parts of methyl vinyl silicone rubber, 15 parts of hydrogen-containing silicone oil, 30 parts of white carbon black, 55 parts of modified aluminum nitride powder, 12 parts of poly(methyl methacrylate) coated magnesium oxide whiskers, 0.4 part of curing agent, and 1.5 parts of peroxide vulcanizing agent; Among them, the volatile content of the hydrogen-containing silicone oil ≤ 300 ppm, and its hydrogen content is 0.19%; the curing agent comprises di-tert-butyl peroxide and vinyltriamine with a weight ratio of 1:1; the peroxide vulcanizing agent is DBPMH; The preparation method of the modified aluminum nitride powder comprises: adding 16 parts of titanate coupling agent into a mixed solution of 22 parts of ethanol and acetone with a volume ratio of 1:1, stirring for dissolution to obtain a mixed solution, adding 110 parts of aluminum nitride powder into the mixed solution, stirring evenly, placing it in a water bath at 70 °C and stirring for 7 h, waiting for the solvent to evaporate completely, drying at 70 °C for 14 h, and then drying at 130 °C for 1.5 h to obtain the product; The aluminum nitride powder comprises aluminum nitride powders with diameters of 2 μm and 15 μm respectively, and the weight ratio is 1:1.5; The preparation method of the polymethyl methacrylate-coated magnesium oxide whiskers comprises: uniformly mixing 100 parts of magnesium oxide whiskers, 4 parts of methyl methacrylate monomer and 0.7 part of azobisisobutyronitrile, and then carrying out microwave polymerization to obtain the product; the parameters of the microwave polymerization are: frequency 90 GHz, temperature 80 °C, time 45 min; In this embodiment, the preparation method of a voltage-resistant thermal insulation gasket comprises the steps of: weighing raw materials in proportion, stirring methyl vinyl silicone rubber, white carbon black, modified aluminum nitride powder, and polymethyl methacrylate-coated magnesium oxide whiskers until evenly mixed to obtain a preliminary material; adding hydrogen-containing silicone oil, curing agent and peroxide vulcanizing agent into the preliminary material, stirring evenly, and carrying out vulcanization at 80 °C to obtain the product.

[0032] Comparative Example 4 This embodiment provides a voltage-resistant thermal insulation gasket, which contains the following materials in parts by weight: 110 parts of methyl vinyl silicone rubber, 15 parts of hydrogen-containing silicone oil, 30 parts of white carbon black, 55 parts of aluminum nitride powder, 12 parts of polymethyl methacrylate-coated magnesium oxide whiskers, 0.4 part of curing agent, and 1.5 parts of peroxide vulcanizing agent; Among them, the volatile content of the hydrogen-containing silicone oil ≤ 300 ppm, and its hydrogen content is 0.19%; the curing agent comprises di-tert-butyl peroxide and vinyltriamine with a weight ratio of 1:1; the peroxide vulcanizing agent is DBPMH; The aluminum nitride powder comprises aluminum nitride powders with diameters of 2 μm and 15 μm respectively, and the weight ratio is 1:1.5; The preparation method of the polymethyl methacrylate-coated magnesium oxide whiskers comprises: uniformly mixing 100 parts of magnesium oxide whiskers, 4 parts of methyl methacrylate monomer and 0.7 part of azobisisobutyronitrile, and then carrying out microwave polymerization to obtain the product; the parameters of the microwave polymerization are: frequency 90 GHz, temperature 80 °C, time 45 min; In this embodiment, a preparation method of a voltage-resistant and heat-conducting insulating gasket comprises the steps of: weighing raw materials in proportion, stirring methyl vinyl silicone rubber, white carbon black, modified aluminum nitride powder, and poly(methyl methacrylate) coated magnesium oxide whiskers until evenly mixed to obtain a preliminary material; adding hydrogen-containing silicone oil, a curing agent, and a peroxide vulcanizing agent to the preliminary material, stirring evenly, and performing vulcanization at 80 °C to obtain the product.

[0033] Comparative Example 5 This embodiment provides a voltage-resistant and heat-conducting insulating gasket, comprising the following materials in parts by weight: 110 parts of methyl vinyl silicone rubber, 15 parts of hydrogen-containing silicone oil, 30 parts of white carbon black, 55 parts of modified aluminum nitride powder, 12 parts of poly(methyl methacrylate) coated magnesium oxide whiskers, 0.4 part of a curing agent, and 1.5 parts of a peroxide vulcanizing agent; Among them, the volatile content of the hydrogen-containing silicone oil ≤ 300 ppm, and its hydrogen content is 0.19%; the curing agent comprises di-tert-butyl peroxide and vinyltriamine with a weight ratio of 1:1; the peroxide vulcanizing agent is DBPMH; The preparation method of the modified aluminum nitride powder comprises: adding 8 parts of a silane coupling agent and 8 parts of a titanate coupling agent to a mixed solution of 22 parts of ethanol and acetone with a volume ratio of 1:1, stirring for dissolution to obtain a mixed solution, adding 110 parts of aluminum nitride powder to the mixed solution, stirring evenly, placing it in a water bath at 70 °C and stirring for 7 h, waiting for the solvent to evaporate completely, drying at 70 °C for 14 h, and then drying at 130 °C for 1.5 h to obtain the product; The diameter of the aluminum nitride powder is 2 μm; The preparation method of the poly(methyl methacrylate) coated magnesium oxide whiskers comprises: mixing 100 parts of magnesium oxide whiskers, 4 parts of methyl methacrylate monomer, and 0.7 part of azobisisobutyronitrile evenly, and then performing microwave polymerization to obtain the product; the parameters of the microwave polymerization are: frequency 90 GHz, temperature 80 °C, and time 45 min; In this embodiment, a preparation method of a voltage-resistant and heat-conducting insulating gasket comprises the steps of: weighing raw materials in proportion, stirring methyl vinyl silicone rubber, white carbon black, modified aluminum nitride powder, and poly(methyl methacrylate) coated magnesium oxide whiskers until evenly mixed to obtain a preliminary material; adding hydrogen-containing silicone oil, a curing agent, and a peroxide vulcanizing agent to the preliminary material, stirring evenly, and performing vulcanization at 80 °C to obtain the product.

[0034] Comparative Example 6 This embodiment provides a voltage-resistant and heat-conducting insulating gasket, comprising the following materials in parts by weight: 110 parts of methyl vinyl silicone rubber, 15 parts of hydrogen-containing silicone oil, 30 parts of white carbon black, 55 parts of modified aluminum nitride powder, 12 parts of poly(methyl methacrylate) coated magnesium oxide whiskers, 0.4 part of a curing agent, and 1.5 parts of a peroxide vulcanizing agent; Among them, the volatile content of the hydrogen-containing silicone oil is ≤300 ppm, and its hydrogen content is 0.19%; the curing agent includes di-tert-butyl peroxide and vinyltriamine with a weight ratio of 1:1; the peroxide vulcanizing agent is DBPMH; The preparation method of the modified aluminum nitride powder includes: adding 8 parts of silane coupling agent and 8 parts of titanate coupling agent into 22 parts of a mixed solution of ethanol and acetone with a volume ratio of 1:1, stirring and dissolving to obtain a mixed solution, adding 110 parts of aluminum nitride powder to the mixed solution, stirring evenly, placing it in a water bath at 70°C and stirring for 7 h, waiting for the solvent to evaporate completely, drying at 70°C for 14 h, and then drying at 130°C for 1.5 h to obtain; The diameter of the aluminum nitride powder is 15 μm; The preparation method of the polymethyl methacrylate-coated magnesium oxide whiskers includes: uniformly mixing 100 parts of magnesium oxide whiskers, 4 parts of methyl methacrylate monomer and 0.7 part of azobisisobutyronitrile, and then performing microwave polymerization to obtain; the parameters of the microwave polymerization are: frequency 90 GHz, temperature 80°C, time 45 min; In this embodiment, a preparation method of a voltage-resistant thermal conductive insulating gasket includes the steps of: weighing raw materials in proportion, stirring methyl vinyl silicone rubber, white carbon black, modified aluminum nitride powder, and polymethyl methacrylate-coated magnesium oxide whiskers until evenly mixed to obtain a preliminary material; adding hydrogen-containing silicone oil, curing agent and peroxide vulcanizing agent to the preliminary material, stirring evenly, and performing vulcanization at 80°C to obtain.

[0035] Comparative Example 7 This embodiment provides a voltage-resistant thermal conductive insulating gasket, which contains the following materials in parts by weight: 110 parts of methyl vinyl silicone rubber, 15 parts of hydrogen-containing silicone oil, 30 parts of white carbon black, 55 parts of modified aluminum nitride powder, 12 parts of magnesium oxide whiskers, 0.4 part of curing agent, and 1.5 parts of peroxide vulcanizing agent; Among them, the volatile content of the hydrogen-containing silicone oil is ≤300 ppm, and its hydrogen content is 0.19%; the curing agent includes di-tert-butyl peroxide and vinyltriamine with a weight ratio of 1:1; the peroxide vulcanizing agent is DBPMH; The preparation method of the modified aluminum nitride powder includes: adding 8 parts of silane coupling agent and 8 parts of titanate coupling agent into 22 parts of a mixed solution of ethanol and acetone with a volume ratio of 1:1, stirring and dissolving to obtain a mixed solution, adding 110 parts of aluminum nitride powder to the mixed solution, stirring evenly, placing it in a water bath at 70°C and stirring for 7 h, waiting for the solvent to evaporate completely, drying at 70°C for 14 h, and then drying at 130°C for 1.5 h to obtain; The aluminum nitride powder includes aluminum nitride powders with diameters of 2 μm and 15 μm with a weight ratio of 1:1.5; In this embodiment, a preparation method of a voltage-resistant and heat-conducting insulating gasket comprises the following steps: weighing raw materials in proportion, and stirring methyl vinyl silicone rubber, fumed silica, modified aluminum nitride powder, and magnesium oxide whiskers until evenly mixed to obtain a preliminary material; adding hydrogen-containing silicone oil, a curing agent, and a peroxide vulcanizing agent to the preliminary material, stirring evenly, and performing vulcanization at 80 °C to obtain the product.

[0036] Test Example 1: Explore the performance of the gaskets prepared in the foregoing Examples 1-4 and Comparative Examples 1-7.

[0037] Mechanical properties: According to the method of ASTM D412-2006 standard, use a universal tensile testing machine to test the tensile strength of the heat-conducting insulating gaskets in the above examples.

[0038] Thermal conductivity: According to the method of ASTM D5470 standard, use a thermal conductivity tester to test the thermal conductivity of the heat-conducting gaskets in the above examples; the sample size is 31 mm × 31 mm, the thickness is 2 mm, the temperature of the upper template is 80 °C, and the pressure is 10 psi.

[0039] Voltage breakdown resistance performance: According to the method of ASTM D149 standard, use a voltage withstand tester to test the breakdown voltage resistance of the heat-conducting gaskets in the above examples.

[0040] Volume resistivity: Test according to ASTM D257, the sample diameter is 100 mm, and the modulation voltage is 500 V.

[0041] The performance test results are shown in Table 1 below:

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the present invention and do not limit the technical solutions described in the present invention; those of ordinary skill in the art should understand that the present invention can still be modified or equivalently replaced; and all technical solutions and their improvements that do not depart from the spirit and scope of the present invention shall be covered by the scope of the claims of the present invention.

Claims

1. A thermally conductive insulating gasket resistant to voltage breakdown, characterized in that: The invention comprises the following materials in parts by weight: 100-120 parts of methyl vinyl silicone rubber, 12-18 parts of hydrogen-containing silicone oil, 28-32 parts of white carbon black, 45-65 parts of modified aluminum nitride powder, 10-14 parts of polymethyl methacrylate-coated magnesium oxide whiskers, 0.3-0.5 parts of curing agent and 1-2 parts of peroxide vulcanizing agent.

2. A thermally conductive insulating gasket capable of withstanding voltage breakdown according to claim 1, characterized in that: The volatility of the hydrogen-containing silicone oil is ≤300ppm, and the hydrogen content thereof is 0.16-0.22%.

3. A thermally conductive insulating gasket capable of withstanding voltage breakdown according to claim 1, characterized in that: The preparation method of the modified aluminum nitride powder comprises: adding a silane coupling agent and a titanate coupling agent into an organic solvent, stirring and dissolving them to obtain a mixed solution, adding aluminum nitride powder into the mixed solution and stirring evenly, placing the mixed solution in a 65-75° C. water bath and stirring for 6-8 hours, drying at 60-80° C. for 12-16 hours after the solvent is evaporated, and then drying at 120-140° C. for 1-2 hours to obtain the modified aluminum nitride powder.

4. A thermally conductive insulating gasket capable of withstanding voltage breakdown according to claim 3, characterized in that: The aluminum nitride powder includes aluminum nitride powders having diameters of 1-3 μm and 14-16 μm respectively in a weight ratio of 1:(1-2).

5. The voltage-breakdown-resistant thermally conductive insulating gasket according to claim 3, characterized in that: The usage ratio of the silane coupling agent, the titanate coupling agent, the organic solvent and the aluminum nitride powder is (6-10): (6-10): (20-24): (105-115).

6. A thermally conductive insulating gasket capable of withstanding voltage breakdown according to claim 5, characterized in that: The organic solvent is a mixture of ethanol and acetone in a volume ratio of 1:

1.

7. The voltage-breakdown-resistant thermally conductive insulating gasket according to claim 1, characterized in that: The preparation method of polymethyl methacrylate coated magnesium oxide whisker comprises: uniformly mixing 100 parts of magnesium oxide whisker, 3-5 parts of methyl methacrylate monomer and 0.5-0.9 parts of azobisisobutyronitrile, and then performing microwave polymerization to obtain the product.

8. The voltage-breakdown-resistant thermally conductive insulating gasket according to claim 7, characterized in that: The parameters of the microwave polymerization are: frequency 85-95 GHz, temperature 75-85° C., and time 30-60 min.

9. The voltage-breakdown-resistant thermally conductive insulating gasket according to claim 1, characterized in that: The curing agent comprises di-tert-butyl peroxide and vinyltriamine in a weight ratio of 1:1; and the peroxide vulcanizing agent is DBPMH.

10. A method for preparing a voltage breakdown resistant thermally conductive insulating gasket as claimed in any one of claims 1 to 9, characterized in that the steps include: Weigh the raw materials according to the proportion, stir the methyl vinyl silicone rubber, white carbon black, modified aluminum nitride powder, and polymethyl methacrylate coated magnesium oxide whisker until they are evenly mixed to obtain a pre-material; Add hydrogen-containing silicone oil, curing agent and peroxide vulcanizing agent to the prepared material, stir evenly, and vulcanize at 75-85°C to obtain the product.

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