Sealing waterproof potting type epoxy glue applied to high-voltage wiring harness and preparation method of sealing waterproof potting type epoxy glue

Abstract

The invention relates to the technical field of epoxy glue processing, in particular to sealing waterproof potting type epoxy glue applied to a high-voltage wire harness and a preparation method of the sealing waterproof potting type epoxy glue. The composite material is prepared from the following raw materials in percentage by weight: 40-50% of polyfunctional epoxy resin, 10-15% of reinforcing filler, 5-8% of heat-conducting filler, 4-5% of nano clay, 3-5% of a CTBN toughening agent, 1-2% of a silane coupling agent, 0.5-1% of an antioxidant, 2-3% of a curing agent and the balance of a diluent. By adopting the formula, the high temperature resistance and aging resistance of the sealing waterproof potting type epoxy glue for the high-voltage wiring harness can be remarkably improved. In a long-time high-temperature environment, the epoxy glue can keep higher insulation resistance and mechanical strength, and the performance reduction caused by softening and aging is reduced, so that the service life of the high-voltage wiring harness is effectively prolonged.

Description

Technical Field

[0001] The present application relates to the technical field of epoxy adhesive processing, and more specifically, to a sealing and waterproof potting type epoxy adhesive used for high-voltage wiring harnesses and a preparation method thereof. Background Art

[0002] High-voltage wire glue, that is, sealant or insulating glue for high-voltage cables, plays a vital role in the manufacturing, installation and maintenance of high-voltage cables for new energy vehicles. It is used to fix cable joints, terminals and other accessories to ensure that they are firmly connected together, prevent current leakage and short-circuit faults, and improve the stability and reliability of the cable system. Among them, epoxy resin is widely used in high-voltage wire harnesses due to its many unique advantages such as high insulation performance, high structural strength and good sealing performance.

[0003] However, high-voltage wires generate a lot of heat during use, and the heat lasts for a long time, which makes the epoxy resin potting glue easy to soften and accelerates aging. The softening of epoxy resin will not only cause its insulation resistance to drop significantly, increasing the risk of leakage or short circuit failure of the cable, but also weaken its original mechanical strength, making the cable more fragile and easy to be damaged when encountering external impact or vibration. These negative effects will inevitably affect the overall reliability of the cable, shorten its service life, and may pose a potential threat to the safe operation of new energy vehicles. Summary of the invention

[0004] In order to solve the problem that epoxy resin will soften and age when it is exposed to high temperature for a long time, the present application provides a sealing and waterproof potting type epoxy adhesive used for high-voltage wiring harness and a preparation method thereof.

[0005] In the first aspect, the present application provides a sealed waterproof potting epoxy adhesive for high voltage wiring harness, which adopts the following technical solution: A sealing and waterproof potting epoxy adhesive for high-voltage wiring harness is prepared from the following raw materials in percentage by weight: Multifunctional epoxy resin 40-50% Reinforcement filler 10-15% Thermal conductive filler 5-8% Nano clay 4-5% CTBN toughening agent 3-5% Silane coupling agent 1-2% Antioxidants 0.5-1% Curing agent 2-3% The remaining amount is diluent; The reinforcing filler is composed of nano silicon dioxide and glass fiber.

[0006] By adopting the above technical solution, the high temperature resistance and anti-aging performance of the sealed waterproof potting epoxy adhesive for high-voltage wiring harnesses can be significantly improved. In a long-term high temperature environment, the epoxy adhesive can maintain a high insulation resistance and mechanical strength, reduce the performance degradation caused by softening and aging, thereby effectively extending the service life of the high-voltage wiring harness and ensuring the safe and reliable operation of the high-voltage wiring harness system of new energy vehicles.

[0007] Among them, by adding nano-silica and glass fiber as reinforcing fillers, the impact resistance and mechanical strength of the epoxy resin glue after curing can be further improved. At the same time, nano-silica can fill the microscopic gaps between the glass fibers, further optimizing the microstructure of the epoxy resin glue, so that the epoxy resin glue can better disperse stress when subjected to external force impact and prevent the expansion of cracks.

[0008] High-voltage cables generate a lot of heat during operation. Thermally conductive fillers can effectively conduct heat, reduce the temperature inside the epoxy adhesive, and reduce the risk of softening and aging caused by high temperature. Thermally conductive fillers and reinforcing fillers work together to form an efficient heat conduction network. The reinforcement effect of nano-silica and glass fiber can ensure the stable dispersion of thermally conductive fillers in the matrix, so that heat can be quickly and evenly conducted away, thereby better protecting the epoxy resin adhesive.

[0009] Nanoclay has good layered structure and barrier properties. It can be evenly dispersed in epoxy resin to form a physical barrier layer to prevent the penetration of moisture and oxygen, further improving the sealing and waterproof properties and antioxidant properties of epoxy glue. At the same time, it can also improve its toughness and heat resistance when dispersed in epoxy resin. It works synergistically with nano-reinforcing fillers and thermal conductive fillers to enhance the overall structural stability of epoxy resin glue. The layered structure of nanoclay can form a composite reinforcement phase with nano-silica and glass fiber, further improving the mechanical properties and heat resistance of the material. At the same time, its barrier properties can effectively delay the aging process of epoxy resin.

[0010] CTBN toughening agent can effectively improve the toughness of epoxy resin, making it less likely to crack when subjected to external impact, improving the impact resistance of the material, and synergizing with nano-reinforcement fillers and nano-clay to form a "rigid and flexible" structure. Nano-reinforcement fillers provide high-strength support, nano-clay provides barrier and reinforcement, and CTBN toughening agent acts as a buffer when epoxy resin glue is subjected to external impact, so that epoxy resin glue has good toughness while maintaining high strength, effectively preventing damage caused by external impact.

[0011] Silane coupling agent can improve the interfacial bonding force between epoxy resin and nano-silica, glass fiber, and nano-clay, enhance the synergistic effect between the components, improve the dispersibility and compatibility of nano-silica, glass fiber, and nano-clay in the epoxy resin matrix, and enhance the heat resistance, aging resistance, and mechanical properties of epoxy resin. Curing agent cross-links with multifunctional epoxy resin to form a stable three-dimensional network structure, giving epoxy glue high strength, high insulation, and good heat resistance. Diluent is used to adjust the viscosity of epoxy glue, so that it has good fluidity during the potting process, can fully fill the gaps in cable joints and other parts, and ensure the sealing effect.

[0012] Preferably, the weight ratio of the nano-silicon dioxide to the glass fiber is (4-6):3.

[0013] By adopting technical solutions, the dosage of nano-silica and glass fiber is optimized so that the two can form a more uniform dispersion structure in the epoxy resin, further disperse the stress, improve the impact resistance and mechanical strength of the epoxy resin glue, and further improve the thermal stability of the epoxy resin glue, reducing the softening and aging of the material in high temperature environment.

[0014] Preferably, the nanoclay is modified nanoclay, which is prepared by the following method: A: Stirring the nanoclay and the acid solution together, then filtering, taking the filter residue, eluting, and obtaining porous clay; B: The porous clay is mixed with a 1-hexadecyl-3-methylimidazolium bromide solution, subjected to ultrasonication, filtered, the filter residue is collected, and dried to obtain modified nano-clay.

[0015] The modified nanoclay is subjected to ultrasonic treatment and surface modification, so that it can be more evenly dispersed in the epoxy resin matrix to form a good interface bond. This uniform dispersion and good bonding can effectively absorb and disperse external forces, improve the toughness of epoxy resin, and reduce the brittle damage of the material when it is impacted or vibrated. Through acid treatment, impurities on the clay surface and between layers can be removed, the pores can be unblocked, and the porous structure can be increased, which helps to absorb and disperse stress and improve the toughness and heat resistance of epoxy resin glue. 1-Hexadecyl-3-methylimidazolium bromide can be inserted into the clay layer through ion exchange, so that the distance between clay layers is increased, and it can be evenly dispersed in the epoxy resin matrix to form a good interface bond. When subjected to external forces, nanoclay can effectively absorb and disperse stress, and improve the toughness and impact resistance of composite epoxy resin glue. At the same time, 1-hexadecyl-3-methylimidazolium bromide has good thermal stability. Ultrasonic mixing of porous clay and 1-hexadecyl-3-methylimidazolium bromide solution improves the heat resistance of epoxy resin glue, which helps to reduce the softening and performance degradation of epoxy resin glue in high temperature environment.

[0016] Preferably, the weight ratio of the nanoclay to the 1-hexadecyl-3-methylimidazolium bromide solution is 1:(4-6).

[0017] By adopting the above technical solution, the weight ratio of nanoclay and 1-hexadecyl-3-methylimidazolium bromide solution is optimized, so that the imidazolium bromide can fully cover the surface of the nanoclay, the heat resistance of the epoxy resin glue is improved, and it helps to reduce the softening and performance degradation of the epoxy resin glue in a high temperature environment.

[0018] Preferably, the multifunctional epoxy resin is composed of bisphenol A epoxy resin and polyphenol glycidyl ether epoxy resin in a weight ratio of 1:(1-3).

[0019] By adopting the above technical solution, bisphenol A epoxy resin has good mechanical strength and bonding properties, while polyphenol glycidyl ether epoxy resin has a large crosslinking density after curing due to the presence of multiple epoxy groups, which further enhances the strength and modulus of the material. The combination of the two makes the epoxy adhesive have higher mechanical strength and better impact resistance after curing. At the same time, the heat resistance of polyphenol glycidyl ether epoxy resin is better than that of bisphenol A epoxy resin. By adjusting the ratio of the two, the heat resistance of epoxy adhesive can be significantly improved while ensuring the mechanical properties, making it more suitable for applications in high-temperature environments such as high-voltage cables for new energy vehicles.

[0020] Preferably, the average particle size of the nano-silicon dioxide is 50-200 nm, and the average particle size of the glass fiber is 5-10 microns.

[0021] By adopting the above technical solution and optimizing the particle size range of nano-silicon dioxide and glass fiber, the high temperature resistance and anti-aging performance of the sealing and waterproof potting epoxy adhesive for high-voltage wiring harnesses can be significantly improved, and its mechanical properties and sealing performance can be optimized. In a long-term high temperature environment, the epoxy adhesive can maintain a high insulation resistance and mechanical strength, reduce the performance degradation caused by softening and aging, and effectively extend the service life of the sealing and waterproof potting epoxy adhesive for high-voltage wiring harnesses.

[0022] Preferably, the curing agent is at least one of DDM, DDS, methylhexahydrophthalic anhydride and bismaleimide.

[0023] By adopting the above technical scheme, the curing of the multifunctional epoxy resin can be further promoted. The cured multifunctional epoxy resin has a higher glass transition temperature and thermal decomposition temperature, and can also significantly improve the mechanical strength and toughness of the multifunctional epoxy resin.

[0024] Preferably, the silane coupling agent is at least one of γ-glycidyloxypropyltrimethoxysilane, γ-glycidyloxypropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-(2,3-epoxypropoxy)propylmethyldimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane and 3-mercaptopropyltrimethoxysilane.

[0025] By adopting the above technical scheme, the types of silane coupling agents are optimized, the dispersibility of nano-silica, glass fiber, and nano-clay in multifunctional epoxy resin is further improved, the agglomeration of nano-silica, glass fiber, and nano-clay is reduced, and their uniform distribution is achieved, thereby further optimizing the mechanical properties and heat resistance of the sealing and waterproof potting epoxy adhesive used in high-voltage wiring harnesses.

[0026] Preferably, the nanoclay is at least one of nano-montmorillonite, nano-kaolinite, nano-halloysite, nano-attapulgite and nano-bentonite.

[0027] The nanoclay has a layered or tubular structure, can form a nanoscale reinforcement phase in the epoxy resin matrix, and can significantly improve the mechanical properties, thermal stability, and high temperature resistance of the sealing and waterproof potting epoxy adhesive for high-voltage wiring harnesses.

[0028] In the second aspect, the present application provides a method for preparing a sealed and waterproof potting epoxy adhesive for a high-voltage wiring harness, which adopts the following technical solution: A method for preparing a sealing and waterproof potting epoxy adhesive for a high-voltage wiring harness comprises the following steps: 1) mixing a reinforcing filler, a thermally conductive filler and a silane coupling agent to obtain a mixture; 2) The multifunctional epoxy resin, nano clay, CTBN toughening agent, antioxidant, curing agent and diluent are stirred evenly, and then added into the mixture and stirred evenly to obtain a sealing and waterproof potting epoxy adhesive for high-voltage wiring harnesses.

[0029] By adopting the above technical solution, each component can be fully and evenly mixed to form a uniform glue system, which is convenient for subsequent construction.

[0030] In summary, this application has the following beneficial effects: 1. This application prepares a sealed waterproof potting epoxy adhesive for high-voltage wiring harnesses by combining multifunctional epoxy resin, nanoclay, CTBN toughening agent, antioxidant, curing agent, reinforcing filler, thermal conductive filler, silane coupling agent and diluent, which significantly improves the high temperature resistance and anti-aging performance of the sealed waterproof potting epoxy adhesive for high-voltage wiring harnesses, and optimizes its mechanical properties and sealing performance. In a long-term high temperature environment, the epoxy adhesive can maintain a high insulation resistance and mechanical strength, reduce the performance degradation caused by softening and aging, thereby effectively extending the service life of the glue and ensuring the safe and reliable operation of the high-voltage wire system of new energy vehicles. DETAILED DESCRIPTION Example

[0031] The CTBN toughening agent was purchased from Hengshui Chituma New Materials Co., Ltd., model LR820.

[0032] Bisphenol A epoxy resin was purchased from Meizhou Fuxi Chemical Co., Ltd., specification 240.

[0033] The polyphenol type glycidyl ether epoxy resin was purchased from Nantong Synasia New Material Technology Co., Ltd., model number S-186.

[0034] Example 1 A sealing and waterproof potting epoxy adhesive for high-voltage wiring harness is prepared by the following method: 1) 100 g of a reinforcing filler, 50 g of a thermally conductive filler (boron nitride) and 10 g of a silane coupling agent (γ-glycidyloxypropyltrimethoxysilane) were mixed to obtain a mixture; 2) 400 g of multifunctional epoxy resin, 40 g of nano clay (nano montmorillonite), 30 g of CTBN toughener, 5 g of antioxidant (antioxidant V-991), 20 g of curing agent (DDM) and 345 g of diluent (1,6-hexanediol diglycidyl ether) are stirred evenly, and then added to the mixture and stirred evenly to obtain a sealing and waterproof potting epoxy adhesive for high-voltage wiring harnesses.

[0035] The reinforcing filler is composed of nano-silicon dioxide and glass fiber in a weight ratio of 1:1. The average particle size of the nano-silicon dioxide is 50nm, and the average particle size of the glass fiber is 5 microns.

[0036] The difference between Example 2-3 and Example 1 is that the raw material types, amounts and parameters for preparing the sealing and waterproof potting epoxy adhesive for high-voltage wiring harness are different. The specific differences are shown in Table 1: Table 1 Raw material types, amounts and parameters for preparing the sealed waterproof potting epoxy adhesive for high voltage wiring harnesses in Examples 1-3 Example 2-3 uses bisphenol A type epoxy resin.

[0037] In Example 2, the reinforcing filler is composed of nano-silicon dioxide and glass fiber in a weight ratio of 1:1. The average particle size of the nano-silicon dioxide is 100 nm, and the average particle size of the glass fiber is 8 microns.

[0038] In Example 3, the reinforcing filler is composed of nano-silicon dioxide and glass fiber in a weight ratio of 1:1. The average particle size of the nano-silicon dioxide is 200 nm, and the average particle size of the glass fiber is 10 microns.

[0039] Example 4 A sealing and waterproof potting epoxy adhesive for use with a high-voltage wiring harness. The difference between this embodiment and embodiment 1 is that the reinforcing filler is composed of nano-silicon dioxide and glass fiber in a weight ratio of 4:3.

[0040] Example 5 A sealing and waterproof potting epoxy adhesive for use with a high-voltage wiring harness. The difference between this embodiment and embodiment 1 is that the reinforcing filler is composed of nano-silicon dioxide and glass fiber in a weight ratio of 6:3.

[0041] Example 6 A sealing and waterproof potting epoxy adhesive for high-voltage wiring harnesses. The difference between this embodiment and embodiment 1 is that the nanoclay is modified nanoclay, which is prepared by the following method: A: 40 g of nanoclay (nano-montmorillonite) and an acid solution (hydrochloric acid solution, 10% by mass) were stirred for 1 hour, then filtered, the residue was taken, and washed to obtain porous clay; B: The porous clay was mixed with 160 g of 1-hexadecyl-3-methylimidazolium bromide solution, subjected to ultrasonic treatment for 30 min, filtered, and the residue was collected and dried to obtain modified nanoclay.

[0042] Example 7 A sealing and waterproof potting epoxy adhesive for high-voltage wiring harnesses. The difference between this embodiment and embodiment 4 is that the nanoclay is modified nanoclay, which is prepared by the following method: A: 40 g of nanoclay (nano-montmorillonite) and an acid solution (sulfuric acid solution, 10% by mass) were stirred for 1 hour, then filtered, the filter residue was taken, and the porous clay was obtained by elution; B: The porous clay was mixed with 240 g of 1-hexadecyl-3-methylimidazolium bromide solution, subjected to ultrasonic treatment for 30 min, filtered, and the residue was collected and dried to obtain modified nanoclay.

[0043] Example 8 A sealed waterproof potting epoxy adhesive for high voltage wiring harness, the difference between this embodiment and embodiment 6 is that the 1-hexadecyl-3-methylimidazolium bromide solution is replaced with pure water. 95.8 Example 9 A sealing and waterproof potting epoxy adhesive for use with a high-voltage wiring harness. The difference between this embodiment and embodiment 6 is that the hydrochloric acid solution is replaced with pure water.

[0044] Example 10 A sealing and waterproof potting epoxy adhesive for use with a high-voltage wiring harness. The difference between this embodiment and embodiment 1 is that the multifunctional epoxy resin is composed of bisphenol A epoxy resin and polyphenol glycidyl ether epoxy resin in a weight ratio of 1:1.

[0045] Embodiment 11 A sealing and waterproof potting epoxy adhesive for use in high-voltage wiring harnesses. The difference between this embodiment and embodiment 7 is that the multifunctional epoxy resin is composed of bisphenol A epoxy resin and polyphenol glycidyl ether epoxy resin in a weight ratio of 1:3.

[0046] Comparative Example Comparative Example 1 A sealing and waterproof potting epoxy adhesive for high-voltage wiring harnesses. The difference between this embodiment and embodiment 1 is that all reinforcing fillers are nano-silicon dioxide.

[0047] Comparative Example 2 A sealing and waterproof potting epoxy adhesive for use with high-voltage wiring harnesses. The difference between this embodiment and embodiment 1 is that all reinforcing fillers are glass fibers.

[0048] Comparative Example 3 A sealing and waterproof potting epoxy adhesive for high-voltage wiring harnesses. The difference between this embodiment and embodiment 1 is that fumed silica is used instead of nano-clay of equal mass.

[0049] Comparative Example 4 A sealing and waterproof potting epoxy adhesive for high-voltage wiring harnesses. The difference between this embodiment and embodiment 1 is that HyPoxRA20 is used instead of an equal mass of CTBN toughening agent.

[0050] HyPoxRA20 was purchased from Guangzhou SiTuYuan Chemical Co., Ltd.

[0051] Detection method / test method Tensile strength test: Tensile properties: According to GB / T2567-2008, the test was carried out using a universal tensile testing machine CMT4202 at 23°C.

[0052] Volume resistivity: Tested at 23°C using resistivity meter ZC-90G according to GB / T31838.2-2019.

[0053] Aging resistance test: The sealed waterproof potting epoxy adhesive for high voltage wiring harnesses prepared in Examples 1-11 and Comparative Examples 1-4 was placed in a 200°C constant temperature oven after curing for 1000 hours, and then taken out to observe whether the surface was powdered, cracked or obviously discolored. If not, the tensile strength and volume resistivity were tested. The experimental data are shown in Table 2: Table 2 Experimental data of Examples 1-11 and Comparative Examples 1-4 By comparing Example 1 with Comparative Example 1, the tensile strength and volume resistivity of Comparative Example 1 before aging are higher than those of Example 1. However, cracking occurs in Comparative Example 1 after the aging test. By comparing Example 1 with Comparative Example 2, the tensile strength and volume resistivity of Comparative Example 2 before aging are lower than those of Example 1, and after the aging test, powdering occurs; It can be seen from the experimental data of Example 1 and Comparative Examples 1-2 that by mixing nano-silicon dioxide and glass fiber in a specific proportion, it can be ensured that the sealed and waterproof potting type epoxy adhesive used for high-voltage wiring harnesses has high tensile strength and volume resistivity, and can also be ensured that the sealed and waterproof potting type epoxy adhesive used for high-voltage wiring harnesses has good heat resistance.

[0054] By comparing Example 1 with Comparative Examples 3-4, the tensile strength and volume resistivity of Example 1 and Comparative Examples 3-4 are basically the same, but after the aging test, cracking occurs in Comparative Example 3 and obvious discoloration occurs in Comparative Example 4, indicating that the use of nanoclay, CTBN toughening agent and other raw materials together is beneficial to improving the heat resistance, tensile strength and insulation of the sealing and waterproof potting epoxy adhesive used in high-voltage wiring harnesses.

[0055] Comparing Example 1 with Example 4-5, the tensile strength of Example 4-5 is improved, and after the aging test, the change rate of the tensile strength is less than that of Example 1, indicating that optimizing the dosage of nano-silica and glass fiber is beneficial to improving the heat resistance and tensile strength of the sealing and waterproof potting epoxy adhesive used in high-voltage wiring harnesses.

[0056] Compared with Example 1 and Example 6, the tensile strength of Example 6 is improved, and after the aging test, the change rate of the tensile strength is less than that of Example 1; Compared with Example 4 and Example 7, the tensile strength of Example 7 is improved, and after the aging test, the change rate of the tensile strength is less than that of Example 4; By comparing Example 6 with Examples 8-9, the tensile strength of Example 6 is higher than that of Examples 8-9, and after the aging test, the change rate of the tensile strength is greater than that of Examples 8-9; From the experimental data of Examples 1 and 6, 4 and 7, and 6 and 8-9, it can be seen that preparing modified nanoclay by the method in the present application is beneficial to improving the heat resistance and tensile strength of the sealing and waterproof potting epoxy adhesive used in high-voltage wiring harnesses.

[0057] By comparing Example 1 with Example 10, the tensile strength and volume resistivity of Example 10 before aging are higher than those of Example 1, and the change rate of the tensile strength after the aging test is greater than that of Example 10; By comparing Example 7 with Example 11, the tensile strength and volume resistivity of Example 11 before aging are higher than those of Example 7, and the change rate of the tensile strength after the aging test is greater than that of Example 7; It can be seen from the experimental data of Examples 1 and 10, 7 and 11 that mixing bisphenol A epoxy resin and polyphenol glycidyl ether epoxy resin is beneficial to improving the heat resistance, tensile strength and insulation of the sealing and waterproof potting epoxy adhesive used in high-voltage wiring harnesses.

[0058] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A sealing and waterproof potting epoxy adhesive for high voltage wiring harness, characterized in that: Prepared from the following raw materials in weight percentage: Multifunctional epoxy resin 40-50% Reinforcement filler 10-15% Thermal conductive filler 5-8% Nano clay 4-5% CTBN toughening agent 3-5% Silane coupling agent 1-2% Antioxidant 0.5-1% Curing agent 2-3% The remaining amount is diluent; The reinforcing filler is composed of nano silicon dioxide and glass fiber.

2. The sealing and waterproof potting epoxy adhesive for high voltage wiring harness according to claim 1, characterized in that: The weight ratio of the nano-silicon dioxide to the glass fiber is (4-6):

3.

3. The sealing and waterproof potting epoxy adhesive for high voltage wiring harness according to claim 2, characterized in that: The nanoclay is modified nanoclay, which is prepared by the following method: A: Stirring the nanoclay and the acid solution together, then filtering, taking the filter residue, eluting, and obtaining porous clay; B: The porous clay is mixed with a 1-hexadecyl-3-methylimidazolium bromide solution, subjected to ultrasonication, filtered, the filter residue is collected, and dried to obtain modified nano-clay.

4. The sealing and waterproof potting epoxy adhesive for high voltage wiring harness according to claim 1, characterized in that: The weight ratio of the nano clay to the 1-hexadecyl-3-methylimidazolium bromide solution is 1:(4-6).

5. The sealing and waterproof potting epoxy adhesive for high voltage wiring harness according to claim 4, characterized in that: The multifunctional epoxy resin is composed of bisphenol A epoxy resin and polyphenol glycidyl ether epoxy resin in a weight ratio of 1: (1-3).

6. The sealing and waterproof potting epoxy adhesive for high voltage wiring harness according to claim 4, characterized in that: The average particle size of the nano silicon dioxide is 50-200 nm, and the average particle size of the glass fiber is 5-10 microns.

7. The sealing and waterproof potting epoxy adhesive for high voltage wiring harness according to claim 1, characterized in that: The curing agent is at least one of DDM, DDS, methylhexahydrophthalic anhydride and bismaleimide.

8. The sealing and waterproof potting epoxy adhesive for high voltage wiring harness according to claim 1, characterized in that: The silane coupling agent is at least one of γ-glycidyloxypropyl trimethoxysilane, γ-glycidyloxypropyl triethoxysilane, γ-(2,3-epoxypropyloxy)propyl trimethoxysilane, γ-(2,3-epoxypropyloxy)propyl methyl dimethoxysilane, 3-glycidyloxypropyl trimethoxysilane, 3-mercaptopropyl triethoxysilane and 3-mercaptopropyl trimethoxysilane.

9. The sealing and waterproof potting epoxy adhesive for high voltage wiring harness according to claim 1, characterized in that: The nano clay is at least one of nano montmorillonite, nano kaolinite, nano halloysite, nano attapulgite and nano bentonite.

10. A method for preparing a sealing and waterproof potting epoxy adhesive for use in a high voltage wiring harness as claimed in any one of claims 1 to 9, characterized in that: The following steps are involved: 1) mixing a reinforcing filler, a thermal conductive filler and a silane coupling agent to obtain a mixture; 2) The multifunctional epoxy resin, nano clay, CTBN toughening agent, antioxidant, curing agent and diluent are stirred evenly, and then added into the mixture and stirred evenly to obtain a sealing and waterproof potting epoxy adhesive for high-voltage wiring harnesses.

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