Epoxy resin encapsulating material for 800V motor rotor as well as preparation and use methods of epoxy resin encapsulating material

Abstract

The invention relates to the technical field of potting adhesives, in particular to the field of IPC C08L63, and more specifically relates to an epoxy resin potting material for a 800V motor rotor and a preparation method and application thereof. Comprising a component A and a component B. The component A comprises, by weight, 15-40 parts of epoxy resin, 50-90 parts of a first filler, 5-15 parts of an epoxy active toughening agent and 0.1-2 parts of a first auxiliary agent. And the component B comprises 50-90 parts of a second filler, 10-30 parts of a curing agent, 10-30 parts of a flame retardant and 0.1-2 parts of a second auxiliary agent. 1, the weight ratio of the bisphenol F type epoxy resin to the bisphenol A type epoxy resin to the alicyclic epoxy resin is 1: (1.5-2.5): (1.5-1.8). The glass transition temperature of the pouring sealant can reach 150 DEG C or above, the gelation time is controlled to be about 150 s, and meanwhile the linear expansion coefficient is 18-24 Tg / ppm / DEG C.

Description

Technical Field

[0001] The present invention relates to the field of potting glue technology, in particular to the field of IPC C08L63, and more specifically to an epoxy resin potting material for an 800V motor rotor and a preparation method and use method thereof. Background Art

[0002] With the new situation of new energy vehicle development, 800V motors have begun to gain a foothold in the industry with their advantages such as high voltage resistance, high frequency and high efficiency. According to the calculation that 10% of my country's new energy vehicle sales in 2023 will be equipped with 800V motors, at least 2,000-2,500 tons of epoxy resin potting materials for 800V motor rotors will be used, generating a profit value of more than 10 million yuan. The powder electrostatic spraying process can no longer meet the use environment of its rotors, and it is easy to produce micro cracks or fall off during operation. At present, the market mostly uses imported epoxy resins to pot and protect the rotors, and there are no mature products in this product field in China.

[0003] CN 116606621 A discloses an epoxy potting adhesive and its preparation method and application, which comprises the following raw materials by weight: 70 to 120 parts of phenolic epoxy resin, 100 to 150 parts of multifunctional epoxy resin, 5 to 15 parts of wetting dispersant, 400 to 700 parts of filler, and the multifunctional epoxy resin is at least one of trifunctional cyclic epoxy resin, trifunctional aromatic epoxy resin and tetrafunctional glycidylamine type epoxy resin. The epoxy potting adhesive provided by the invention has excellent heat resistance, a glass transition temperature of more than 175°C, and good mechanical properties, but the linear expansion coefficient is too large and does not meet the application requirements of 800V motor rotors. Summary of the invention

[0004] A first aspect of the present invention provides an epoxy resin potting material for an 800V motor rotor, comprising a component A and a component B. Measured in parts by weight, the component A comprises: 15-40 parts of epoxy resin, 50-90 parts of a first filler, 5-15 parts of an epoxy active toughening agent, and 0.1-2 parts of a first auxiliary agent; the component B comprises: 50-90 parts of a second filler, 10-30 parts of a curing agent, 10-30 parts of a flame retardant, and 0.1-2 parts of a second auxiliary agent.

[0005] Preferably, in parts by weight, the component A comprises: 15-25 parts of epoxy resin, 60-80 parts of first filler, 5-10 parts of epoxy active toughening agent, and 0.1-1 parts of first auxiliary agent; the component B comprises: 60-80 parts of second filler, 10-20 parts of curing agent, 15-20 parts of flame retardant, and 0.1-1 parts of second auxiliary agent.

[0006] The epoxy resin includes bisphenol F epoxy resin, bisphenol A epoxy resin and alicyclic epoxy resin, and the weight ratio of the bisphenol F epoxy resin, bisphenol A epoxy resin and alicyclic epoxy resin is 1:(1-3):(1-2).

[0007] Preferably, the weight ratio of the bisphenol F epoxy resin, the bisphenol A epoxy resin, and the alicyclic epoxy resin is 1:(1.5-2.5):(1.5-1.8).

[0008] The present application has found that the weight ratio of the bisphenol F epoxy resin, bisphenol A epoxy resin and alicyclic epoxy resin is 1:(1.5-2.5):(1.5-1.8). The glass transition temperature of the potting glue can reach above 150°C, the gelation time can be controlled at about 150s, and the linear expansion coefficient is 18-24Tg / ppm / °C. The glass transition temperature of epoxy resin will increase as the rigidity of the molecular chain inside the polymer increases and the free volume decreases, and its thermal expansion coefficient is mainly related to the cross-linking density and molecular structure of the epoxy resin. The molecular chains of bisphenol F epoxy resin and bisphenol A epoxy resin are short and the epoxy groups at both ends are close. The curing system formed after the cross-linking reaction has more dense cross-linking points, which controls the reaction rate and stabilizes the gel time, but at the same time limits the thermal stability of the potting compound. The addition of alicyclic epoxy resin, because the main body of its molecular structure contains more long flexible chain segments, makes the rigidity of the molecular chain segments of bisphenol A epoxy resin weaker than that of bisphenol F epoxy resin, and adjusts the defects of a large number of benzene rings restricting the movement of molecular chain segments, thereby improving the stability of the potting compound.

[0009] Preferably, the epoxy value of the bisphenol F epoxy resin is 0.4-0.8 mol / 100 g, and more preferably, the epoxy value is 0.5-0.65 mol / 100 g.

[0010] Preferably, the epoxy value of the bisphenol A epoxy resin is 0.2-0.6 mol / 100 g, and more preferably, the epoxy value is 0.3-0.5 mol / 100 g.

[0011] Preferably, the epoxy value of the alicyclic epoxy resin is 0.5-1.2 mol / 100 g, and more preferably, the epoxy value is 0.6-0.9 mol / 100 g.

[0012] The epoxy value of the epoxy reactive toughening agent is 0.3-0.6 mol / 100g, and more preferably, the epoxy value is 0.3-0.5 mol / 100g.

[0013] Preferably, the epoxy reactive toughening agent comprises core-shell polybutadiene rubber, and the content of the core-shell polybutadiene rubber is 20-50wt%.

[0014] The applicant has found that the epoxy reactive toughening agent comprises core-shell polybutadiene rubber, the content of the core-shell polybutadiene rubber is 20-50wt%, and the amount of the epoxy reactive toughening agent and the alicyclic epoxy resin is limited at the same time, which can improve the bending strength while maintaining the glass transition temperature. It may be that the epoxy groups in the epoxy reactive toughening agent and the epoxy resin form a good dispersion, and the core-shell polybutadiene rubber contained is then evenly dispersed in the three-dimensional network of the epoxy resin, reducing the slip between the epoxy segments of the potting glue under the action of external force.

[0015] The first filler includes metal oxide and nitride, and the weight ratio of the metal oxide to the nitride is (3-10):1.

[0016] Preferably, the first filler comprises metal oxide and nitride, and the weight ratio of the metal oxide to the nitride is (4-8):1.

[0017] The second filler includes metal oxide and nitride, and the weight ratio of the metal oxide to the nitride is (6-12):1.

[0018] Preferably, the second filler comprises metal oxide and nitride, and the weight ratio of the metal oxide to the nitride is (8-12):1.

[0019] The metal oxide includes one or more of beryllium oxide, magnesium oxide, zinc oxide and aluminum oxide.

[0020] Preferably, the metal oxide comprises spherical alumina, and the D50 particle size of the alumina is 2-5 microns.

[0021] The nitride includes one or more of aluminum nitride, boron nitride, and silicon nitride.

[0022] Preferably, the nitride comprises hexagonal boron nitride, and the D50 particle size of the hexagonal boron nitride is 2-8 microns.

[0023] The present application has found that the first filler includes metal oxide and nitride, and the weight ratio of the metal oxide and nitride is (3-10): 1. And it is limited that the metal oxide includes spherical aluminum oxide, and the nitride includes hexagonal boron nitride. The thermal conductivity and high and low temperature impact performance of the potting glue can be improved. The excellent properties of boron nitride itself, such as high thermal conductivity and low dielectric constant, make it widely used in insulating and thermally conductive packaging materials. However, due to the relative inertness of boron and nitrogen atoms on the surface of boron nitride, it is difficult to form a good interaction with the polymer matrix material, thereby affecting its dispersion in the polymer matrix and the application of the structure of the thermally conductive filler inside the material. The addition of metal oxide may have a certain flexibility while ensuring insulation and thermal conductivity through specific bonding, improve its dispersion in the matrix and the structure of the thermally conductive filler, reduce the interface thermal resistance between the inorganic filler and the epoxy resin, and further improve the thermal conductivity.

[0024] Further research found that the D50 particle size of the aluminum oxide is limited to 2-5 microns and the D50 particle size of the hexagonal boron nitride is limited to 2-8 microns. The thermal conductivity can reach 1.6W / mK, which meets the requirements for 800V motor rotor potting. It is speculated that under the same filling amount, the hexagonal boron nitride particle size is larger, the hexagonal boron nitride particles dispersed in the epoxy resin matrix are loosely stacked, and there are gaps between the particles, which is not conducive to the formation of a thermal conduction channel; while the aluminum oxide with a slightly smaller particle size just fills these gaps, and the particles are more densely stacked, thereby better forming a thermal conduction channel. At the same time, the hexagonal crystal form of boron nitride and the spherical structure of aluminum oxide further meet the effect of close stacking, further improving the thermal conductivity.

[0025] The first auxiliary agent includes at least one of an anti-settling agent, a defoaming agent, and a toner.

[0026] Preferably, the first auxiliary agent includes an anti-settling agent, a defoaming agent, and a toner.

[0027] Preferably, the flame retardant comprises a flame retardant anhydride.

[0028] The curing agent includes at least one of tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, nadic anhydride and methylnadic anhydride.

[0029] Preferably, the curing agent includes at least one of tetrahydrophthalic anhydride, hexahydrophthalic anhydride and methyltetrahydrophthalic anhydride.

[0030] The second auxiliary agent includes at least one of an anti-settling agent, a defoaming agent, a dispersant, and a accelerator.

[0031] Preferably, the second auxiliary agent includes an anti-settling agent, a defoaming agent, a dispersant, and a accelerator.

[0032] A second aspect of the present invention provides a method for preparing an epoxy resin potting material for an 800V motor rotor, comprising the following steps:

[0033] S1, adding epoxy resin, a first filler, and an epoxy active toughening agent, kneading, heating, and vacuum degassing in sequence, then adding a first auxiliary agent and mixing evenly, cooling, and filtering to obtain component A;

[0034] S2, adding a second filler, a curing agent, a flame retardant, and a second auxiliary agent, and stirring evenly to obtain component B.

[0035] A third aspect of the present invention provides a method for using an epoxy resin potting material for an 800V motor rotor, comprising the following steps: mixing component A and component B evenly, pouring the mixture into a mold and curing the mixture.

[0036] The weight ratio of the component A to the component B is 1:(1-1.5).

[0037] Preferably, the weight ratio of component A to component B is 1:(1-1.2).

[0038] The curing includes primary curing and secondary curing in sequence. The time of the primary curing is 0.5-1.5 hours and the temperature is 90-120° C.; the time of the secondary curing is 2-4 hours and the temperature is 130-160° C.

[0039] Preferably, the time of the primary curing is 0.5-1h, and the temperature is 90-110°C; the time of the secondary curing is 2-3h, and the temperature is 140-160°C.

[0040] Beneficial Effects

[0041] 1. The weight ratio of the bisphenol F epoxy resin, bisphenol A epoxy resin and alicyclic epoxy resin is 1:

[0042] (1.5-2.5): (1.5-1.8). The glass transition temperature of the potting glue can reach above 150°C, the gelation time can be controlled at about 150s, and the linear expansion coefficient is at 18-24Tg / ppm / °C.

[0043] 2. The epoxy active toughening agent comprises core-shell polybutadiene rubber, the content of the core-shell polybutadiene rubber is 20-50wt%, and the amount of the epoxy active toughening agent and the alicyclic epoxy resin is limited, so that the bending strength can be improved while maintaining the glass transition temperature.

[0044] 3. The first filler includes metal oxide and nitride, and the weight ratio of the metal oxide to the nitride is (3-10): 1. The metal oxide includes spherical aluminum oxide, and the nitride includes hexagonal boron nitride. The thermal conductivity and high and low temperature impact performance of the potting glue can be improved.

[0045] 4. The D50 particle size of the aluminum oxide is limited to 2-5 microns, and the D50 particle size of the hexagonal boron nitride is limited to 2-8 microns. The thermal conductivity can reach 1.6W / mK, meeting the requirements for 800V motor rotor potting.

[0046] 5. Component A and component B of the present application have good storage stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is a picture of the finished product of the potting glue of Example 3 applied to the rotor motor.

[0048] Figure 2 This is a cross-sectional view of the potting compound of Example 3 applied to a rotor motor. DETAILED DESCRIPTION

[0049] Examples 1-3

[0050] An epoxy resin potting material for an 800V motor rotor, the components of which are shown in Tables 1-3, wherein Table 1 corresponds to the components of Example 1, Table 2 corresponds to the components of Example 2, and Table 3 corresponds to the components of Example 3.

[0051] Table 1 Table 2

[0052]

[0053]

[0054] Table 3

[0055]

[0056] The component manufacturers and models are shown in Table 4:

[0057] Table 4

[0058]

[0059] A method for preparing an epoxy resin potting material for an 800V motor rotor comprises the following steps:

[0060] S1, add epoxy resin, first filler, epoxy active toughening agent, knead (rotation speed 1000r / min; time 1.5 hours), heat up (temperature controlled at 80±5°C; grinder uses heat transfer oil; other equipment uses heating belt), vacuum degassing (temperature 105°C; vacuum degree -0.092Mpa; time 1 hour), cool to 65°C, add first auxiliary agent and mix well, cool (50°C), filter to obtain component A;

[0061] S2, adding a second filler, a curing agent, a flame retardant, and a second auxiliary agent, and stirring evenly to obtain component B.

[0062] A method for using an epoxy resin potting material for an 800V motor rotor comprises the following steps: preheating components A and B at 80°C respectively; mixing components A and B evenly, with component A: component B = 100:110 (wt%), and weighing about 1000g; pouring the mixed material into a mold; using a triangular bracket to stably suspend the motor so that its copper coil is immersed in the material and 3mm away from the bottom of the mold; pushing the motor, a suspension frame and the mold as a whole into a high-temperature oven and curing according to specified curing conditions; after curing, cooling to room temperature, taking the motor out of the mold and the suspension frame to obtain a finished product.

[0063] Performance Testing Methods

[0064] The A and B components obtained in the example were tested for appearance, density and viscosity, and the test data are listed in Table 6.

[0065] The mixture was mixed according to component A: component B = 100:110 (wt%), and cured at 100°C / 1h+150°C / 3h. The hardness, glass transition temperature, thermal conductivity, bending strength, high and low temperature impact, flame retardancy, and gelation time (glue curing time tester: GT-II) were tested. The test standards are shown in Table 5, and the test results are shown in Table 6.

[0066] The finished product and cross-sectional diagrams after using the potting glue in Example 3 are as follows: Figure 1 and Figure 2 shown.

[0067] Table 5

[0068] project Testing standards project Testing standards hardness GB / T 2411-2008 Linear expansion coefficient GB / T 1036-2008 Glass transition temperature (Tg) GB / T 1634-2004 Bending Strength GB / T 9341-2008 Thermal conductivity ASTM E1461-2013 Flame retardant GB / T 2408-2008

[0069] Performance test data

[0070] Table 6

[0071]

[0072]

Claims

1. An epoxy resin potting material for an 800V motor rotor, characterized in that: The invention comprises component A and component B. Calculated by weight, the component A comprises: 15-40 parts of epoxy resin, 50-90 parts of first filler, 5-15 parts of epoxy active toughening agent, and 0.1-2 parts of first auxiliary agent; the component B comprises: 50-90 parts of second filler, 10-30 parts of curing agent, 10-30 parts of flame retardant, and 0.1-2 parts of second auxiliary agent.

2. The 800V motor rotor epoxy resin potting material according to claim 1, characterized in that: The epoxy resin includes bisphenol F epoxy resin, bisphenol A epoxy resin, and alicyclic epoxy resin, and the weight ratio of the bisphenol F epoxy resin, bisphenol A epoxy resin, and alicyclic epoxy resin is 1: (1-3)：(1-2)。 3. The epoxy resin potting material for 800V motor rotor according to claim 2, characterized in that: The first filler includes metal oxide and nitride, and the weight ratio of the metal oxide to the nitride is (3-10):

1.

4. The epoxy resin potting material for 800V motor rotor according to claim 3, characterized in that: The first auxiliary agent includes at least one of an anti-settling agent, a defoaming agent, and a toner.

5. The 800V motor rotor epoxy resin potting material according to claim 1 or 4, characterized in that: The curing agent includes at least one of tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, nadic anhydride and methylnadic anhydride.

6. The epoxy resin potting material for 800V motor rotor according to claim 5, characterized in that: The second auxiliary agent includes at least one of an anti-settling agent, a defoaming agent, a dispersant, and a accelerator.

7. A method for preparing the epoxy resin potting material for 800V motor rotor according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1, adding epoxy resin, a first filler, and an epoxy active toughening agent, kneading, heating, and vacuum degassing in sequence, then adding a first auxiliary agent and mixing evenly, cooling, and filtering to obtain component A; S2, adding a second filler, a curing agent, a flame retardant, and a second auxiliary agent, and stirring evenly to obtain component B.

8. A method for using the epoxy resin potting material for 800V motor rotor according to any one of claims 1 to 6, characterized in that: The following steps are involved: Mix components A and B evenly and pour into the mold for curing.

9. The method for using the epoxy resin potting material for 800V motor rotor according to claim 8, characterized in that: The weight ratio of the component A to the component B is 1:(1-1.5).

10. The method for using the epoxy resin potting material for 800V motor rotor according to claim 9, characterized in that: The curing includes primary curing and secondary curing in sequence, and the time of the primary curing is The time for the secondary curing is 2-4 hours, and the temperature is 130-160°C.

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