A method for preparing a two-component epoxy potting resin

Abstract

The application discloses a preparation method of a two-component epoxy pouring resin, which comprises a component A and a component B, the component A and the component B are prepared respectively during preparation, and the component A and the component B are mixed according to a formula during use; wherein the component A comprises liquid epoxy resin, castor oil polyoxyethylene ether modified solid epoxy resin, epoxy active diluent and heat-conducting filler, the component B comprises a curing agent, the castor oil polyoxyethylene ether modified solid epoxy resin is generated by carrying out a hydroxyl condensation reaction between hydroxyl groups in castor oil polyoxyethylene ether with a molecular weight of 3500 and solid epoxy resin with a molecular weight of 2000 and containing hydroxyl groups; the epoxy pouring resin prepared by the method has good heat conductivity, and the heat-conducting filler basically does not have a sedimentation phenomenon during storage and use, the viscosity is moderate, the pouring process is suitable, and the epoxy pouring resin is applied to a transformer.

Description

[0001] This invention is a divisional application of Chinese invention patent application filed on July 27, 2022, with application number 2022108899246 and titled "A two-component high thermal conductivity epoxy potting resin and its preparation method and application". Technical Field

[0002] This invention relates to the field of insulation materials technology, and more particularly to insulation materials for cast-type dry-type transformers, specifically to a method for preparing a two-component epoxy potting resin. Background Technology

[0003] As transformer efficiency increases, the requirements for heat dissipation also become more stringent. The main challenge in transformer heat dissipation lies in the potting compound layer between the coil and the transformer's metal casing. When this potting compound has a high thermal conductivity, the heat generated during coil operation can be dissipated more quickly to the heat sinks on the transformer's metal casing, reducing heat accumulation inside the transformer, lowering the internal temperature, minimizing potting compound aging, reducing the likelihood of high-temperature fires, and extending the transformer's lifespan. High-heat-dissipation transformer units can also improve their operating efficiency and extend their overload time. However, current high-thermal-conductivity potting compounds often contain a high content of thermally conductive fillers, which are prone to sedimentation during storage and use. This uneven filler content in the compound layer leads to differences in thermal conductivity in different areas, and in severe cases, can cause the compound layer to crack.

[0004] Meanwhile, current technologies for epoxy potting resins often employ thickening methods such as fumed silica to address the issues of poor stability and easy sedimentation. While these methods improve stability to some extent, in practical applications, adding too little will not achieve a stabilizing effect, while adding too much will result in excessive viscosity, which cannot meet the requirements of the potting process. Summary of the Invention

[0005] The purpose of this invention is to overcome one or more shortcomings of the prior art and provide an improved method for preparing a two-component epoxy potting resin. The epoxy potting resin prepared by this method not only has excellent thermal conductivity, but also ensures that the thermally conductive filler does not undergo sedimentation during storage and use. This ensures that the thermal conductivity of different parts of the potting resin remains consistent, reduces heat accumulation inside the transformer, lowers the internal temperature of the transformer, reduces the aging of the transformer potting compound, reduces the possibility of high-temperature fire in the transformer, and extends the service life of the transformer.

[0006] To achieve the above objectives, the present invention provides a technical solution comprising: a two-component epoxy potting resin, comprising component A and component B, wherein component A comprises liquid epoxy resin, epoxy reactive diluent, and thermally conductive filler, and component B comprises a curing agent, wherein:

[0007] Component A further comprises castor oil polyoxyethylene ether modified solid epoxy resin, which is generated by a hydroxyl condensation reaction between the hydroxyl groups in the castor oil polyoxyethylene ether and a solid epoxy resin containing hydroxyl groups. The mass ratio of the castor oil polyoxyethylene ether to the solid epoxy resin containing hydroxyl groups is 0.5-2:1. The molecular weight of the castor oil polyoxyethylene ether is 3500 or higher, and the molecular weight of the solid epoxy resin containing hydroxyl groups is 2000 or higher.

[0008] According to some preferred and specific aspects of the present invention, the hydroxyl-containing solid epoxy resin is a bisphenol A type solid epoxy resin.

[0009] Furthermore, the bisphenol A type solid epoxy resin is one or more of E-12 epoxy resin, E-06 epoxy resin, and E-03 epoxy resin.

[0010] According to some preferred aspects of the present invention, the mass ratio of the castor oil polyoxyethylene ether to the hydroxyl-containing solid epoxy resin is 1-1.5:1.

[0011] According to some preferred aspects of the present invention, the mass ratio of the liquid epoxy resin to the castor oil polyoxyethylene ether modified solid epoxy resin is 0.6-0.85:1.

[0012] According to some preferred aspects of the present invention, the mass ratio of the liquid epoxy resin, the castor oil polyoxyethylene ether modified solid epoxy resin, and the thermally conductive filler is 0.3-0.55:0.4-0.7:1, and the amount of castor oil polyoxyethylene ether modified solid epoxy resin is greater than the amount of liquid epoxy resin.

[0013] According to some preferred and specific aspects of the present invention, the castor oil polyoxyethylene ether is one or a combination of castor oil polyoxyethylene ether EL-60, castor oil polyoxyethylene ether EL-80, and castor oil polyoxyethylene ether EL-90.

[0014] According to some preferred aspects of the present invention, the method for preparing the castor oil polyoxyethylene ether modified solid epoxy resin includes: dispersing a hydroxyl-containing solid epoxy resin in an epoxy reactive diluent, then adding castor oil polyoxyethylene ether, and reacting at 150-170°C to generate the epoxy resin.

[0015] In some preferred embodiments of the present invention, the liquid epoxy resin is one or more of E-51 epoxy resin, E-44 epoxy resin, F-51 epoxy resin, and Hein epoxy resin.

[0016] In some preferred embodiments of the present invention, the epoxy reactive diluent is one or more of the following: butyl glycidyl ether, 1,4-butanediol diglycidyl ether, ethylene glycol diglycidyl ether, benzyl glycidyl ether, phenyl glycidyl ether, neopentyl glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and C12-14 fatty glycidyl ether.

[0017] In some preferred embodiments of the present invention, the curing agent is one or more of aliphatic amine type curing agents, aromatic amine type curing agents, and polyether amine type curing agents. Further, the aliphatic amine type curing agent can be a modified aliphatic amine, such as cashew phenol-modified aliphatic amine MD7209 from Anhui Meidong Chemical Co., Ltd., and the aromatic amine type curing agent can be a modified aromatic amine, such as modified polyether amine MD1800 from Anhui Meidong Chemical Co., Ltd.

[0018] According to some preferred aspects of the invention, the thermally conductive filler comprises at least two types of thermally conductive particles with different average particle sizes, and the average particle size of each pair of thermally conductive particles differs by 2-10 μm.

[0019] According to some preferred aspects of the invention, the thermally conductive particles comprise alumina and a combination of one or more selected from magnesium oxide, magnesium hydroxide, aluminum hydroxide, boron nitride, and aluminum nitride, wherein the alumina accounts for more than 35% by mass of the thermally conductive filler. In the system of the present invention, alumina is a better thermally conductive particle than others, as it can achieve good thermal conductivity without significantly increasing the viscosity of the system.

[0020] According to some preferred aspects of the invention, the average particle size of the thermally conductive particles is selected from the following particle size: A, B, C, or D:

[0021] Particle size A is 1-2 micrometers, particle size B is 5-8 micrometers, particle size C is 10-15 micrometers, and particle size D is 20-30 micrometers.

[0022] According to some preferred aspects of the present invention, the mass ratio of component A to component B is 8-12:1.

[0023] According to some preferred aspects of the present invention, the A component comprises, by weight percentage, 10%-25% liquid epoxy resin, 15%-30% castor oil polyoxyethylene ether modified solid epoxy resin, 5%-20% epoxy reactive diluent and 35%-60% thermally conductive filler.

[0024] Component B is a curing agent.

[0025] In some embodiments of the present invention, component A further includes toughening agents, defoamers, and color pastes.

[0026] Another technical solution provided by the present invention: a method for preparing the above-mentioned two-component epoxy potting resin, the preparation method comprising the following steps:

[0027] Preparation of component A:

[0028] The epoxy reactive diluent is preheated, then a solid epoxy resin containing hydroxyl groups is added, and after mixing, castor oil polyoxyethylene ether is added. The mixture is reacted at 150-170℃ to generate castor oil polyoxyethylene ether modified solid epoxy resin dispersed in the epoxy reactive diluent, thus obtaining a reaction mixture.

[0029] Preheat the liquid epoxy resin, add it to the reaction mixture, mix well, add the remaining components of component A, mix, and obtain component A;

[0030] Preparation of component B: Mix all components of component B to obtain component B.

[0031] In some preferred embodiments of the present invention, during the preparation of component A, the preheating operation of the epoxy reactive diluent can heat the epoxy reactive diluent to 90-110°C.

[0032] In some preferred embodiments of the present invention, the reaction time of the reaction during the preparation of component A is 0.5-2 hours.

[0033] In some preferred embodiments of the present invention, during the preparation of component A, the preheating operation of the liquid epoxy resin can heat the liquid epoxy resin to 75-85°C and maintain it at 75-85°C for 2-6 hours.

[0034] Another technical solution provided by the present invention: the application of the above-mentioned two-component epoxy potting resin in cast transformers.

[0035] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0036] This invention innovatively uses high-molecular-weight castor oil polyoxyethylene ether to modify high-molecular-weight solid epoxy resin containing hydroxyl groups. The castor oil polyoxyethylene ether is grafted onto the solid epoxy resin via hydroxyl condensation, forming long-chain side branches on the epoxy macromolecules. Furthermore, this invention uses liquid epoxy resin and castor oil polyoxyethylene ether-modified solid epoxy resin to jointly constitute the resin system. Practice has shown that these long branches generate significant steric hindrance in the system, effectively preventing or even inhibiting the sedimentation of thermally conductive fillers. Simultaneously, these castor oil polyoxyethylene ether branches are very flexible, avoiding a significant increase in system viscosity that could affect casting performance. In addition, the system of this invention has good thermal conductivity and low viscosity, around 1200 mPa·s at 40°C, making it suitable for potting processes. Detailed Implementation

[0037] The above-mentioned solution will be further described below with reference to specific embodiments; it should be understood that these embodiments are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited to the scope of the following embodiments; the implementation conditions used in the embodiments can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in conventional experiments.

[0038] Unless otherwise specified in the following examples, all raw materials are commercially available or prepared by conventional methods in the art.

[0039] In the following description, E-51, F-51, E-44, and E-12 epoxy resins were all purchased from Nantong Xingchen Chemical, Haiyin epoxy resin was purchased from Hubei Xitai Chemical, epoxy reactive diluents were 692 and 678 epoxy reactive diluents from Hubei Green Home Co., Ltd., castor oil polyoxyethylene ether EL-60, castor oil polyoxyethylene ether EL-90, and castor oil polyoxyethylene ether EL-20 were purchased from Zhejiang Huangma, defoamer was Deqian 6800, toughening agent was Qishi QS-50N, color paste was alcohol-soluble aniline black and iron yellow dye, and curing agent was cashew phenol modified fatty amine MD7209 and modified polyether amine MD1800 from Anhui Meidong Chemical.

[0040] Example 1

[0041] This example provides a two-component epoxy potting resin and its preparation method. The two-component epoxy potting resin comprises component A and component B, wherein:

[0042] The raw materials for component A include: 20 kg of E-51 epoxy resin, 15 kg of 678 epoxy diluent, 15 kg of castor oil polyoxyethylene ether EL-60, 12 kg of E-12 epoxy resin, 10 kg of 2-micron aluminum hydroxide, 34 kg of 5-micron aluminum oxide, 9 kg of 10-micron magnesium oxide; 0.1 kg of Deqian 6800 defoamer, and 5 kg of toughening agent QS-50N;

[0043] Component B includes: MD7209.

[0044] Preparation of castor oil polyoxyethylene ether modified solid epoxy resin:

[0045] (1) Heat 15 kg of 678 epoxy reactive diluent to 100°C, then slowly add 12 kg of E-12 epoxy resin and mix evenly;

[0046] (2) Add 15 kg of castor oil polyoxyethylene ether EL-60 to the mixture obtained above, heat to 160°C, and react for 0.5 hours to obtain castor oil polyoxyethylene ether modified E-12 epoxy resin A, and obtain the reaction mixture.

[0047] The preparation method of the two-component epoxy potting resin includes the following steps:

[0048] (1) Preheat 20 kg of E-51 epoxy resin at 80°C for 4 hours, then add the reaction mixture and stir until homogeneous;

[0049] (2) First, add toughening agent QS-50N, then slowly add thermally conductive filler (10 kg 2-micron aluminum hydroxide, 34 kg 5-micron aluminum oxide, 9 kg 10-micron magnesium oxide) in sequence, then disperse at high speed for 1 hour, finally add defoamer Deqian 6800, and continue stirring for 30 minutes to obtain component A.

[0050] (3) The curing agent is packaged in a mass ratio of A:B = 10:1 to obtain component B.

[0051] Example 2

[0052] This example is the same as Example 1, except that:

[0053] Preparation of castor oil polyoxyethylene ether modified solid epoxy resin:

[0054] (2) Add 15 kg of castor oil polyoxyethylene ether EL-60 to the mixture obtained above, heat to 160°C, and react for 2 hours to obtain castor oil polyoxyethylene ether modified E-12 epoxy resin B.

[0055] Example 3

[0056] This example is the same as Example 1, except that:

[0057] Preparation of castor oil polyoxyethylene ether modified solid epoxy resin:

[0058] (2) Add 15 kg of castor oil polyoxyethylene ether EL-90 to the mixture obtained above, heat to 160°C, and react for 0.5 hours to obtain castor oil polyoxyethylene ether modified E-12 epoxy resin C.

[0059] Example 4

[0060] This example provides a two-component epoxy potting resin and its preparation method. The two-component epoxy potting resin comprises component A and component B, wherein:

[0061] The raw materials for component A include 20 kg of E-51 epoxy resin, 15 kg of 678 epoxy diluent, 15 kg of castor oil polyoxyethylene ether EL-60, 12 kg of E-12 epoxy resin, 8 kg of 2-micron aluminum hydroxide, 40 kg of 10-micron aluminum oxide, 5 kg of 10-micron magnesium oxide; 0.1 kg of Deqian 6800 defoamer, and 5 kg of toughening agent QS-50N;

[0062] Component B includes: MD7209;

[0063] Preparation of castor oil polyoxyethylene ether modified solid epoxy resin:

[0064] (1) Heat 15 kg of 678 epoxy reactive diluent to 100°C, then slowly add 12 kg of E-12 epoxy resin and mix evenly.

[0065] (2) Add 15 kg of castor oil polyoxyethylene ether EL-60 to the mixture obtained above, heat to 160°C, and react for 0.5 hours to obtain castor oil polyoxyethylene ether modified E-12 epoxy resin A, and obtain the reaction mixture.

[0066] The preparation method of the two-component epoxy potting resin includes the following steps:

[0067] (1) Preheat 20 kg of E-51 epoxy resin at 80°C for 4 hours, then add the reaction mixture and stir until homogeneous;

[0068] (2) First, add toughening agent QS-50N, then slowly add thermally conductive filler (8 kg 2-micron aluminum hydroxide, 40 kg 10-micron aluminum oxide, 5 kg 10-micron magnesium oxide) in sequence, then disperse at high speed for 1 hour, finally add defoamer, and continue stirring for 30 minutes to obtain component A.

[0069] (3) The curing agent is packaged in a mass ratio of A:B = 10:1 to obtain component B.

[0070] Example 5

[0071] This example provides a two-component epoxy potting resin and its preparation method. The two-component epoxy potting resin comprises component A and component B, wherein:

[0072] The raw materials for component A include: 20 kg of E-51 epoxy resin, 15 kg of 678 epoxy diluent, 15 kg of castor oil polyoxyethylene ether EL-60, 12 kg of E-12 epoxy resin, 15 kg of 2-micron aluminum hydroxide, 20 kg of 10-micron aluminum oxide, 12 kg of 20-micron magnesium oxide; 0.1 kg of Deqian 6800 defoamer, and 5 kg of toughening agent QS-50N;

[0073] Component B includes: MD7209;

[0074] Preparation of castor oil polyoxyethylene ether modified solid epoxy resin:

[0075] (1) Heat 15 kg of 678 epoxy reactive diluent to 100°C, then slowly add 12 kg of E-12 epoxy resin and mix evenly.

[0076] (2) Add 15 kg of castor oil polyoxyethylene ether EL-60 to the mixture obtained above, heat to 160°C, and react for 0.5 hours to obtain castor oil polyoxyethylene ether modified E-12 epoxy resin A, and obtain the reaction mixture.

[0077] The preparation method of the two-component epoxy potting resin includes the following steps:

[0078] (1) Preheat 20 kg of E-51 epoxy resin at 80°C for 4 hours, then add the reaction mixture and stir until homogeneous;

[0079] (2) First, add toughening agent QS-50N, then slowly add thermally conductive filler (15 kg 2-micron aluminum hydroxide, 20 kg 10-micron aluminum oxide, 12 kg 20-micron magnesium oxide) in sequence, then disperse at high speed for 1 hour, finally add defoamer, and continue stirring for 30 minutes to obtain component A.

[0080] (3) The curing agent is packaged in a mass ratio of A:B = 10:1 to obtain component B.

[0081] Comparative Example 1

[0082] The method is basically the same as in Example 1, except that in component A, 15 kg of castor oil polyoxyethylene ether EL-60 and 12 kg of E-12 epoxy resin are omitted, and the amount of E-51 epoxy resin is adjusted to 47 kg.

[0083] The preparation method of the two-component epoxy potting resin includes the following steps:

[0084] (1) Preheat 47 kg of E-51 epoxy resin at 80°C for 4 hours;

[0085] (2) First, add toughening agent QS-50N, then slowly add thermally conductive filler (10 kg 2-micron aluminum hydroxide, 34 kg 5-micron aluminum oxide, 9 kg 10-micron magnesium oxide) in sequence, then disperse at high speed for 1 hour, finally add defoamer Deqian 6800, and continue stirring for 30 minutes to obtain component A.

[0086] (3) The curing agent is packaged in a mass ratio of A:B = 10:1 to obtain component B.

[0087] Comparative Example 2

[0088] The process is basically the same as in Example 1, except that in component A, 20 kg of E-51 epoxy resin is omitted, castor oil polyoxyethylene ether EL-60 is adjusted to 26 kg, and E-12 epoxy resin is adjusted to 21 kg.

[0089] Specifically, the preparation of castor oil polyoxyethylene ether modified solid epoxy resin:

[0090] (1) Heat 15 kg of 678 epoxy reactive diluent to 100°C, then slowly add 21 kg of E-12 epoxy resin and mix evenly;

[0091] (2) Add 26 kg of castor oil polyoxyethylene ether EL-60 to the mixture obtained above, heat to 160°C, and react for 0.5 hours to obtain castor oil polyoxyethylene ether modified E-12 epoxy resin and obtain the reaction mixture.

[0092] The preparation method of the two-component epoxy potting resin includes the following steps:

[0093] (1) Stir the reaction mixture thoroughly;

[0094] (2) First, add toughening agent QS-50N, then slowly add thermally conductive filler (10 kg 2-micron aluminum hydroxide, 34 kg 5-micron aluminum oxide, 9 kg 10-micron magnesium oxide) in sequence, then disperse at high speed for 1 hour, finally add defoamer Deqian 6800, and continue stirring for 30 minutes to obtain component A.

[0095] (3) The curing agent is packaged in a mass ratio of A:B = 10:1 to obtain component B.

[0096] Comparative Example 3

[0097] The process is basically the same as in Example 1, except that in component A, castor oil polyoxyethylene ether EL-60 is replaced with castor oil polyoxyethylene ether EL-20.

[0098] Comparative Example 4

[0099] The process is basically the same as in Example 1, except that in component A, E-12 epoxy resin is replaced with liquid epoxy resin E-44 epoxy resin.

[0100] Performance testing

[0101] (1) Viscosity test

[0102] The viscosity of the two-component epoxy potting resins prepared according to the methods of Examples 1-4 and Comparative Examples 1-4 was tested at different temperatures, and the results are shown in Table 1 below.

[0103] Table 1

[0104]

[0105]

[0106] Note: When measuring viscosity by rotational viscosity, first heat component A and component B to the required temperature, adjust the water temperature of the rotational viscometer to the required temperature, mix component A and component B in a mass ratio of 10:1, and the viscosity measurement must be completed within 5 minutes, otherwise the viscosity will be inaccurate due to the reaction.

[0107] (2) Storage stability test

[0108] The storage stability of the two-component epoxy potting resins prepared according to the methods of Examples 1-4 and Comparative Examples 1-4 was tested, and the results are shown in Table 2 below.

[0109] Initial mixing viscosity: Component A of the two-component epoxy potting resin was loaded into a plastic measuring cylinder to a height of 30cm. Immediately afterwards, the top 15cm of material was mixed with component B at a mass ratio of 10:1, and the viscosity was tested at 40℃.

[0110] Viscosity after 20 days at 50℃: Component A of the two-component epoxy potting resin was loaded into a plastic measuring cylinder to a height of 30cm. The cylinder was then placed in an oven at 50℃ and kept at that temperature for 20 days. The top 15cm of material was mixed with component B of the curing agent at a mass ratio of 10:1, and the viscosity was tested at 40℃.

[0111] Table 2

[0112]

[0113]

[0114] Note: When measuring viscosity by rotational viscometry, first heat components A and B to the required temperatures, adjust the water temperature of the rotational viscometer to the required temperature, mix components A and B in a mass ratio of 10:1, and the viscosity measurement must be completed within 5 minutes, otherwise the viscosity will be inaccurate due to the reaction.

[0115] The results show that although the system using only modified epoxy resin has high stability, the viscosity is too high to meet the casting process requirements. The system without or with unsuitable castor oil polyoxyethylene ether modified solid epoxy resin has a significantly lower viscosity, indicating poor stability. The system with the addition of the specific castor oil polyoxyethylene ether modified solid epoxy resin of this invention has significantly improved storage stability.

[0116] (3) Stability test during curing process

[0117] The two-component epoxy potting resins prepared by the methods of Examples 1-5 and Comparative Examples 1-4 were cured to obtain the finished product. The specific potting steps are as follows:

[0118] (1) Preheat components A and B to about 40°C, and preheat the mold to about 70°C;

[0119] (2) Mix components A and B evenly in a mass ratio of 10:1, then pour the mixture into the mold at an appropriate speed, keeping the sample thickness at about 10 mm, and then vacuum to remove air bubbles.

[0120] (3) Curing at 60℃ for 6 hours;

[0121] (4) After curing, remove the mold from the oven and let it cool at room temperature for 15 minutes before removing the sample.

[0122] (5) Prepare 6 sample blocks for each sample. Grind 3 sample blocks starting from the top surface to a thickness of 3-4 mm, and grind 3 sample blocks starting from the bottom surface to a thickness of 3-4 mm. Then measure the thermal conductivity. The test results are shown in Table 3.

[0123] Table 3

[0124]

[0125] As can be seen from Table 3, during the curing process, all modified epoxy resins were used. Although the stability was very high, the viscosity of the system was too high to meet the casting process. In the system without or with unsuitable castor oil polyoxyethylene ether modified solid epoxy resin, the filler showed obvious sedimentation. However, the system with the specific castor oil polyoxyethylene ether modified solid epoxy resin of this invention showed very good stability and the thermal conductivity was basically the same.

[0126] (4) Other performance tests

[0127] The two-component epoxy potting resins prepared by the methods of Examples 1-5 and Comparative Examples 1-4 were cured to obtain the finished product. The specific potting steps are as follows:

[0128] (1) Preheat components A and B to about 40°C, and preheat the mold to about 70°C;

[0129] (2) Mix components A and B evenly in a mass ratio of 10:1, then pour the mixture into the mold at an appropriate speed, keeping the sample thickness at about 4 mm, and then vacuum to remove air bubbles.

[0130] (3) Curing at 60℃ for 6 hours;

[0131] (4) After curing, remove the mold from the oven and let it cool at room temperature for 15 minutes before removing the sample.

[0132] (5) Grind the sample block to the required size.

[0133] The results are shown in Table 4-5.

[0134] Table 4

[0135]

[0136]

[0137] Table 5

[0138]

[0139] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

[0140] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

Claims

1. A method for preparing a two-component epoxy potting resin comprising a part A and a part B, characterized in that: The preparation method comprises the following steps: Preparation of the A component: The A component comprises a castor oil polyoxyethylene ether modified solid epoxy resin, a liquid epoxy resin, an epoxy reactive diluent and a heat-conducting filler; in terms of mass percentage, the liquid epoxy resin accounts for 10%-25%, the castor oil polyoxyethylene ether modified solid epoxy resin accounts for 15%-30%, the epoxy reactive diluent accounts for 5%-20% and the heat-conducting filler accounts for 35%-60% in the A component; The epoxy reactive diluent is preheated, then the solid epoxy resin containing a hydroxyl group is added, the castor oil polyoxyethylene ether is added after mixing, and the reaction is carried out at 150-170℃ to generate the castor oil polyoxyethylene ether modified solid epoxy resin dispersed in the epoxy reactive diluent, thereby obtaining a reaction mixture; wherein the mass ratio of the castor oil polyoxyethylene ether to the solid epoxy resin containing a hydroxyl group is 0.5-2:1, the molecular weight of the castor oil polyoxyethylene ether is above 3500, and the molecular weight of the solid epoxy resin containing a hydroxyl group is above 2000; The liquid epoxy resin is preheated and added into the reaction mixture, and the other remaining components in the A component are added and mixed to obtain the A component; Preparation of the B component: The B component comprises a curing agent; The components of the B component are mixed to obtain the B component.

2. The method for preparing the two-component epoxy potting resin according to claim 1, characterized in that: In the preparation process of the A component, the preheating operation of the epoxy reactive diluent is to heat the epoxy reactive diluent to 90-110℃.

3. The method for preparing the two-component epoxy potting resin according to claim 1, characterized in that: In the preparation process of the A component, the reaction time of the reaction is 0.5-2h.

4. The method for preparing the two-component epoxy potting resin according to claim 1, characterized in that: In the preparation process of the A component, the preheating operation of the liquid epoxy resin is to heat the liquid epoxy resin to 75-85℃, and the liquid epoxy resin is kept at 75-85℃ for 2-6h.

5. The method for preparing the two-component epoxy potting resin according to claim 1, characterized in that: The A component further comprises a toughening agent, a defoaming agent and a color paste.

6. The method for preparing the two-component epoxy potting resin according to claim 1, characterized in that: The mass ratio of the A component to the B component is 8-12:

1.

7. The method for preparing the two-component epoxy potting resin according to claim 1, characterized in that: The mass ratio of the liquid epoxy resin, the castor oil polyoxyethylene ether modified solid epoxy resin and the heat-conducting filler is 0.3-0.55:0.4-0.7:1, and the castor oil polyoxyethylene ether modified solid epoxy resin is added in a larger amount than the liquid epoxy resin.

8. The method for preparing the two-component epoxy potting resin according to claim 7, characterized in that: The castor oil polyoxyethylene ether is a combination of one or more of castor oil polyoxyethylene ether EL-60, castor oil polyoxyethylene ether EL-80 and castor oil polyoxyethylene ether EL-90.

9. The method for preparing the two-component epoxy potting resin according to claim 1, characterized in that: The curing agent is cashew phenol modified aliphatic amine MD7209 and / or modified polyether amine MD1800.

10. The method for preparing the two-component epoxy potting resin according to claim 1, characterized in that: The mass ratio of the castor oil polyoxyethylene ether to the solid epoxy resin containing a hydroxyl group is 1-1.5:1, and the mass ratio of the liquid epoxy resin to the castor oil polyoxyethylene ether modified solid epoxy resin is 0.6-0.85:

1.

11. The method for preparing the two-component epoxy potting resin according to claim 1, characterized in that: The solid epoxy resin containing a hydroxyl group is a bisphenol A type solid epoxy resin, which is a combination of one or more of E-12 epoxy resin, E-06 epoxy resin and E-03 epoxy resin; The liquid epoxy resin is a combination of one or more selected from E-51 epoxy resin, E-44 epoxy resin, F-51 epoxy resin and hydantoin epoxy resin; The epoxy reactive diluent is a combination of one or more selected from the group consisting of butyl glycidyl ether, 1,4-butanediol diglycidyl ether, ethylene glycol diglycidyl ether, benzyl glycidyl ether, phenyl glycidyl ether, neopentyl glycol diglycidyl ether, polypropylene glycol diglycidyl ether, C12-14 fatty glycidyl ether.

12. The method for preparing the two-component epoxy potting resin according to claim 1, characterized in that: The thermally conductive filler comprises at least two kinds of thermally conductive particles with different average particle sizes, and the average particle sizes of the thermally conductive particles differ by 2-10 μm. The thermally conductive particles comprise alumina and optionally one or more selected from the group consisting of magnesium oxide, magnesium hydroxide, aluminum hydroxide, boron nitride and aluminum nitride.

13. The method for preparing the two-component epoxy potting resin according to claim 12, characterized in that: The mass percentage of the alumina in the thermally conductive filler is 35% or more.

14. The method for preparing the two-component epoxy potting resin according to claim 12, characterized in that: The average particle size of the thermally conductive particles is selected from the group consisting of A particle size of 1-2 microns, B particle size of 5-8 microns, C particle size of 10-15 microns, and D particle size of 20-30 microns.

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