Flame-retardant insulating paint for electric vehicle motor and preparation method and use thereof

Abstract

The present application relates to a kind of electric vehicle motor with flame-retardant insulating paint and its preparation method and purposes.The raw materials of the insulating paint include polyester resin, curing agent, initiator and diluent, the polyester resin is unsaturated polyester resin containing halogen, which is made by halogenated phthalic anhydride, polybasic acid and polyhydric alcohol, the raw materials of the insulating paint also include diisocyanate, modified titanium dioxide nanotube, the modified titanium dioxide nanotube is prepared by silane coupling agent modification of titanium dioxide nanotube, the flame-retardant insulating paint is prepared by the reaction of halogenated phthalic anhydride, polybasic acid, polyhydric alcohol and modified titanium dioxide nanotube, to obtain unsaturated polyester resin containing halogen containing modified titanium dioxide nanotube, then it is reacted with diisocyanate, curing agent, initiator and diluent.The insulating paint has excellent performance such as flame-retardant, toughness, thermal stability, corrosion resistance and wear resistance.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of electric vehicle motor with flame-retardant insulating paint and its preparation method and use. BACKGROUND

[0002] Insulating material is one of the key materials in the manufacture of automobile motor; Because it involves vehicle and personal safety, it has higher technical requirements on safety, durability and reliability, such as flame retardance, toughness, thermal stability, corrosion resistance and wear resistance. Ordinary insulating material is poor in flame retardance, and in high-speed running motor, it is easy to overheat, and even the insulating material on the motor rotor may catch fire. At the same time, ordinary insulating material also has the problem of not being resistant to ATF oil (automatic transmission oil).

[0003] Chinese patent CN109486378A discloses a kind of electric vehicle with ATF oil resistant flame-retardant insulating paint and its preparation method and application, the raw materials of the flame-retardant insulating paint include polyester resin, curing agent, initiator, diluent, diisocyanate. The polyester resin is unsaturated polyester resin containing halogen, which is made by reacting halogenated phthalic anhydride, polybasic acid and polyol, the polybasic acid is at least two kinds selected from adipic acid, phthalic acid, maleic anhydride and glutaric anhydride, and the polyol is at least two kinds selected from propylene glycol, 1,4-butanediol and ethylene glycol. Although the flame-retardant insulating paint has good flame retardance and insulation, it still needs to be further improved.

[0004] Most of the insulating paint for electric vehicle motor today is poor in flame retardance, toughness, thermal stability, corrosion resistance and wear resistance because it uses high molecular material. In order to further improve the performance of the insulating paint, it is necessary to add inorganic material, but in order to obtain high performance, it is generally necessary to have high doping content. However, high doping has the problem of poor compatibility between doping particles and insulating paint. On the one hand, due to the large size of the doping particles and uneven dispersion, it is difficult to achieve good compounding effect. On the other hand, the incompatibility between high-doped inorganic material and polymer matrix limits the further improvement of the overall performance of the insulating paint, resulting in that the existing high molecular insulating paint for electric vehicle motor is not good enough in flame retardance, toughness, thermal stability, corrosion resistance and wear resistance. SUMMARY

[0005] The technical problem to be solved by the present application is to provide an improved flame-retardant insulating paint for electric vehicle motor, which has excellent performance such as flame retardance, toughness, thermal stability, corrosion resistance and wear resistance.

[0006] To solve the above technical problems, the technical solution adopted by the present application is as follows:

[0007] The application discloses a fire-retardant insulating paint for an electric vehicle motor, raw materials of the fire-retardant insulating paint comprising a polyester resin, a curing agent, an initiator and a diluent, the polyester resin being an unsaturated polyester resin containing halogen, the unsaturated polyester resin containing halogen being prepared by reacting halogenated phthalic anhydride, polybasic acid and polyhydric alcohol, the raw materials of the fire-retardant insulating paint further comprising diisocyanate, and the raw materials of the fire-retardant insulating paint further comprising modified titanium dioxide nanotubes, the modified titanium dioxide nanotubes being prepared by modifying titanium dioxide nanotubes by a silane coupling agent, the fire-retardant insulating paint being prepared by reacting halogenated phthalic anhydride, polybasic acid, polyhydric alcohol and modified titanium dioxide nanotubes to obtain the unsaturated polyester resin containing halogen containing modified titanium dioxide nanotubes, and then reacting the unsaturated polyester resin containing halogen containing modified titanium dioxide nanotubes with diisocyanate, a curing agent, an initiator and a diluent.

[0008] In some embodiments, the mass of the modified titanium dioxide nanotubes is 3%-9% of the mass of the fire-retardant insulating paint.

[0009] In some embodiments, the silane coupling agent is selected from a combination of one or more of KH550, KH560 and KH570.

[0010] In some embodiments, the modified titanium dioxide nanotubes are prepared by mixing titanium dioxide nanotubes with an ethanol solution of a silane coupling agent, and drying.

[0011] In some embodiments, in the ethanol solution of the silane coupling agent, the volume ratio of the silane coupling agent to ethanol is 1:10.

[0012] In some embodiments, the feeding molar ratio of the halogenated phthalic anhydride, the polybasic acid and the polyhydric alcohol is 1:2.5-4.0:2.0-3.5.

[0013] In some embodiments, the polybasic acid is at least two selected from adipic acid, phthalic acid, maleic anhydride and glutaric anhydride, and the polyhydric alcohol is at least two selected from propylene glycol, 1,4-butanediol and ethylene glycol.

[0014] In some embodiments, the polybasic acid is composed of adipic acid and maleic anhydride, and the feeding molar ratio of the adipic acid to the maleic anhydride is 0.4-0.6:1.

[0015] In some embodiments, the polyhydric alcohol is composed of propylene glycol and ethylene glycol, and the feeding molar ratio of the propylene glycol to the ethylene glycol is 1.1-1.8:1.

[0016] In some embodiments, the mass ratio of the diisocyanate to the halogen-containing unsaturated polyester resin is 0.05-0.15:1.

[0017] In some embodiments, the halogenated phthalic anhydride is tetrabromophthalic anhydride and / or tetrachlorophthalic anhydride.

[0018] In some embodiments, the diisocyanate is a combination of one or more selected from the group consisting of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate and hexamethylene diisocyanate.

[0019] In some embodiments, the curing agent is a combination of one or more selected from the group consisting of aluminum acetylacetonate, chromium acetylacetonate and zinc naphthenate.

[0020] In some embodiments, the initiator is dicumyl peroxide.

[0021] In some embodiments, the diluent is styrene and / or vinyl styrene.

[0022] The present application further provides a method for preparing the aforementioned flame-retardant insulating paint for electric vehicle motors, which comprises the following steps: weighing each raw material according to the formula, mixing the weighed halogen-containing unsaturated polyester resin containing modified titanium dioxide nanotubes, polybasic acid, and polyol, and allowing the mixture to undergo polycondensation reaction at 190-200℃ until the acid value is ≤50mg KOH / g, thereby preparing the halogen-containing unsaturated polyester resin containing modified titanium dioxide nanotubes; cooling to 100-120℃, adding a solvent, continuing to cool to 50-70℃, adding diisocyanate dropwise, allowing the mixture to react at a temperature less than 100℃, continuing to heat the mixture after the addition is completed, adding the remaining raw materials after the solvent is separated, and mixing, thereby obtaining the flame-retardant insulating paint for electric vehicle motors.

[0023] In some embodiments, the method further comprises the steps of preparing the titanium dioxide nanotubes by using anatase titanium dioxide powder to perform hydrothermal reaction, and preparing the modified titanium dioxide nanotubes by mixing the titanium dioxide nanotubes with an ethanol solution of silane coupling agent and drying.

[0024] The present application further provides the use of the aforementioned flame-retardant insulating paint for electric vehicle motors in insulating paint for electric vehicle motors.

[0025] Thanks to the use of the above technical solutions, the present application has the following advantages compared with the prior art:

[0026] The present application adds the modified titanium dioxide nanotube after adding the silane coupling agent to the flame-retardant insulating paint with the resin obtained after the reaction of the halogen-containing unsaturated polyester resin and the diisocyanate as the main component, and controls the specific adding time of the modified titanium dioxide nanotube, i.e. adding in the in-situ polymerization of the halogen-containing unsaturated polyester resin, so that the modified titanium dioxide nanotube is added into the reaction system at the same time with the halogenated phthalic anhydride, the polybasic acid and the polyhydric alcohol, which can reduce the surface energy of the titanium dioxide nanotube on one hand, so that it is easy to disperse uniformly in the resin matrix, and obviously improves the problem of easy agglomeration and uneven dispersion of the inorganic particles in the prior art, and on the other hand, can obviously improve the comprehensive performance of the flame-retardant insulating paint, such as the flame retardancy, the toughness, the thermal stability, the corrosion resistance and the wear resistance, and improves the problem that the flame-retardant insulating paint of the high molecular matrix in the prior art is not excellent enough in performance when used in the electric motor of the electric vehicle. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The morphology of the modified titanium dioxide nanotube in Example 1. DETAILED DESCRIPTION

[0028] The technical scheme of the present application will be described in detail below in combination with specific examples, so that the technical scheme of the present application can be better understood and implemented by the person skilled in the art, but the present application is not limited in the scope of the described examples.

[0029] Example 1

[0030] The present embodiment provides a flame-retardant insulating paint for electric motor of electric vehicle, and the preparation method is as follows:

[0031] 1) Preparation of titanium dioxide nanotube: add the anatase phase titanium dioxide powder (particle size of about 500 nanometers) and the 10M concentration NaOH solution in the mass ratio of 1:5 in the high-pressure reaction kettle, seal and hydrothermal reaction at 140℃ for 72 hours; after the reaction kettle is cooled, the white solid is removed from the high-pressure reaction kettle and washed with 0.1M hydrochloric acid (HCl) solution, then washed with a large amount of deionized water until the pH value of the outflowing solution is neutral. Finally, the titanium dioxide nanotube product is dried at 80℃ to obtain the titanium dioxide nanotube.

[0032] 2) Preparation of modified titanium dioxide nanotube: add the titanium dioxide nanotube obtained in step 1) into the anhydrous ethanol solution of silane coupling agent KH560 (the volume ratio of silane coupling agent and anhydrous ethanol is 1:10), the mass percentage of titanium dioxide nanotube in the anhydrous ethanol solution is 10%, ultrasonic dispersion treatment for 10 minutes; then oil bath treatment at 400℃ for 4 hours; after the oil bath, the flocculation obtained by reaction is repeatedly washed with anhydrous ethanol and deionized water, suction filtered, and naturally dried at room temperature to obtain the modified titanium dioxide nanotube, and the morphology is as shown inFigure 1 As shown, the tube diameter is 10-20 nm and the length is 100-500 nm.

[0033] 3) Preparation of flame-retardant insulating paint: raw materials include modified titanium dioxide nanotubes 18 g obtained in step 2), tetrabromophthalic anhydride 190 g, adipic acid 72 g, maleic anhydride 93 g, propylene glycol 52 g, ethylene glycol 28 g, diphenyl methane diisocyanate 38 g, stabilizer 0.05 g, styrene 96 g, initiator dicumyl peroxide 7 g and curing agent 6 g;

[0034] According to the formula, each raw material is weighed, the weighed tetrabromophthalic anhydride, adipic acid, maleic anhydride, propylene glycol, ethylene glycol and modified titanium dioxide nanotubes are mixed, a polycondensation reaction occurs at 190°C until the acid value is ≤50 mgKOH / g, a halogen-containing unsaturated polyester resin containing modified titanium dioxide nanotubes is prepared; cool to 100°C, add toluene solvent, continue to cool to 50°C, add diphenyl methane diisocyanate dropwise, react, and control the temperature in the reaction process to be less than 100°C, continue to react for 2 h after the dropwise addition is completed; vacuum for 1 h, separate the toluene solvent, then add the stabilizer, styrene, cool to room temperature, then add the initiator and curing agent, mix, to obtain the flame-retardant insulating paint, which contains 3% of the modified titanium dioxide nanotubes by mass percentage.

[0035] Example 2

[0036] This example provides a flame-retardant insulating paint for electric vehicle motors, and the preparation method is basically the same as that of Example 1, except that the mass of the modified titanium dioxide nanotubes in step 3) is adjusted to 30 g, and the obtained flame-retardant insulating paint contains 5% of the modified titanium dioxide nanotubes by mass percentage.

[0037] Example 3

[0038] This example provides a flame-retardant insulating paint for electric vehicle motors, and the preparation method is basically the same as that of Example 1, except that the mass of the modified titanium dioxide nanotubes in step 3) is adjusted to 42 g, and the obtained flame-retardant insulating paint contains 7% of the modified titanium dioxide nanotubes by mass percentage.

[0039] Example 4

[0040] This example provides a flame-retardant insulating paint for electric vehicle motors, and the preparation method is basically the same as that of Example 1, except that the mass of the modified titanium dioxide nanotubes in step 3) is adjusted to 54 g, and the obtained flame-retardant insulating paint contains 9% of the modified titanium dioxide nanotubes by mass percentage.

[0041] Comparative Example 1

[0042] The comparative example 3 provides a flame-retardant insulating paint for electric vehicle motor, and its preparation method is basically the same as that of the example 3, except that the step 1) is not performed, and the titanium dioxide nanotubes in the step 2) are replaced by aluminum oxide nanometer particles (with a particle size of about 100 nanometers), which are used in the step 3).

[0043] Comparative example 2

[0044] The comparative example 3 provides a flame-retardant insulating paint for electric vehicle motor, and its preparation method is basically the same as that of the example 3, except that the step 1) is not performed, and the titanium dioxide nanotubes in the step 2) are replaced by aluminum oxide nanometer particles (with a particle size of about 100 nanometers), which are used in the step 3).

[0045] Comparative example 3

[0046] The comparative example 3 provides a flame-retardant insulating paint for electric vehicle motor, and its preparation method is basically the same as that of the example 3, except that the step 1) is not performed, and the titanium dioxide nanotubes in the step 2) are replaced by aluminum oxide nanometer particles (with a particle size of about 100 nanometers), which are used in the step 3).

[0047] The raw materials are weighed according to the formula, the halogen-containing unsaturated polyester resin is prepared by mixing tetrabromophthalic anhydride, adipic acid, maleic anhydride, propylene glycol and ethylene glycol, and subjecting them to polycondensation reaction at 190°C until the acid value is less than or equal to 50 mgKOH / g; the temperature is lowered to 100°C, toluene solvent is added, and the temperature is further lowered to 50°C, and diphenylmethane diisocyanate is added dropwise, the reaction is controlled at a temperature less than 100°C, and after the dropwise addition is completed, the reaction is continued for 2h; vacuum is applied for 1h, the toluene solvent is separated, and then the stabilizer, styrene and modified titanium dioxide nanotubes are added, and the mixture is cooled to room temperature, and then the initiator and curing agent are added and mixed to obtain the flame-retardant insulating paint, which contains 7% of the modified titanium dioxide nanotubes by mass percentage.

[0048] Comparative example 4

[0049] The comparative example 3 provides a flame-retardant insulating paint for electric vehicle motor, and its preparation method is basically the same as that of the example 3, except that the step 1) is not performed, and the titanium dioxide nanotubes in the step 2) are replaced by aluminum oxide nanometer particles (with a particle size of about 100 nanometers), which are used in the step 3).

[0050] Comparative example 5

[0051] The comparative example provides a flame-retardant insulating paint for an electric vehicle motor, the preparation method of which is basically the same as that of Example 3, the difference being that step 1) is not performed, the titanium dioxide nanotubes in step 2) are replaced by silica nanoparticles (particle size of about 100 nanometers), and they are used in step 3).

[0052] After the flame-retardant insulating paints prepared in Examples 1-4 and Comparative Examples 1-5 are sprayed on the substrate, the performance of the cured coating film and the performance of the cured coating film after being immersed in ATF oil for 3 months are tested according to GB / 15022.2-2017, and the results are shown in Tables 1-2 below, where “-” means that the data under this condition does not exist, because the insulating paint is first cured, then solidified, and then immersed in ATF oil for 3 months, and the data will not be tested after 3 months.

[0053] Table 1 Performance of cured coating film of Example

[0054]

[0055] Table 2 Performance of cured coating film of Comparative Example

[0056]

[0057]

[0058] As can be seen from Tables 1 and 2 above, by adding the titanium dioxide nanotubes modified by the silane coupling agent in the flame-retardant insulating paint having the resin obtained by reacting the halogen-containing unsaturated polyester resin and the diisocyanate as the main component, and controlling the specific addition timing of the modified titanium dioxide nanotubes, i.e., adding them during the in-situ polymerization of the halogen-containing unsaturated polyester resin, the flame-retardant insulating paint containing them can have excellent various performances such as flame retardancy, toughness, thermal stability, corrosion resistance, and wear resistance.

[0059] The above examples are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and to implement it, and it cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit and essence of the present application should be covered within the protection scope of the present application.

[0060] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The ranges or values should be construed to be roughly about the ranges or values. The endpoints of the ranges of values will be understood to be roughly about the endpoint value. Individual point values will be understood to be roughly about the point value. Ranges involving endpoints will be understood to include new ranges created by combining the endpoints.

Claims

1. A fire-retardant insulating paint for an electric motor of an electric vehicle, the fire-retardant insulating paint comprising, as raw materials, a polyester resin, a curing agent, an initiator, and a diluent, the polyester resin being an unsaturated polyester resin containing halogen, the unsaturated polyester resin containing halogen being made by reacting halogenated phthalic anhydride, a polybasic acid, and a polyhydric alcohol, the fire-retardant insulating paint further comprising diisocyanate, characterized in that: The raw material of the flame-retardant insulating paint also comprises modified titanium dioxide nanotubes, which are prepared by modifying titanium dioxide nanotubes with a silane coupling agent.

2. The fire-retardant insulating paint for an electric vehicle motor according to claim 1, characterized by: The silane coupling agent is selected from one or a combination of KH550, KH560 and KH570.

3. The fire-retardant insulating paint for an electric vehicle motor according to claim 1, characterized by: The modified titanium dioxide nanotubes are prepared by mixing titanium dioxide nanotubes with an ethanol solution of the silane coupling agent and drying.

4. The fire-retardant insulating paint for an electric vehicle motor according to claim 1, characterized by: The molar ratio of the halogenated phthalic anhydride, the polybasic acid and the polyhydric alcohol is 1:2.5-4.0:2.0-3.

5.

5. The fire-retardant insulating paint for an electric vehicle motor according to claim 1, characterized in that: The polybasic acid is at least two selected from adipic acid, phthalic acid, maleic anhydride and glutaric anhydride, and the polyhydric alcohol is at least two selected from propylene glycol, 1,4-butanediol and ethylene glycol.

6. The fire-retardant insulating paint for an electric vehicle motor according to claim 1, characterized by: The mass ratio of the diisocyanate to the halogen-containing unsaturated polyester resin is 0.05-0.15:

1.

7. The fire-retardant insulating paint for an electric vehicle motor according to claim 1, characterized by: The halogenated phthalic anhydride is tetrabromophthalic anhydride and / or tetrachlorophthalic anhydride.

8. The fire-retardant insulating paint for an electric vehicle motor according to claim 1, characterized by: The diisocyanate is one or a combination of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate and hexamethylene diisocyanate.

9. The fire-retardant insulating paint for an electric vehicle motor according to claim 1, characterized by: The curing agent is one or a combination of aluminum acetylacetone, chromium acetylacetone and zinc naphthenate.

10. The fire-retardant insulating paint for an electric vehicle motor according to claim 1, characterized by: The initiator is dicumyl peroxide.

11. The fire-retardant insulating paint for an electric vehicle motor according to claim 1, characterized by: The diluent is styrene.

12. A process for preparing a fire-retardant insulating paint for an electric motor of an electric vehicle as claimed in any one of claims 1 to 11, characterized in that: The method The method comprises the following steps: weighing each raw material according to the formula, mixing the weighed halogenated phthalic anhydride, polybasic acid, modified titanium dioxide nanotubes and polyhydric alcohol, and performing polycondensation reaction at 190-200℃ until the acid value is ≤50mg KOH / g to obtain halogen-containing unsaturated polyester resin containing modified titanium dioxide nanotubes; cooling to 100-120℃, adding a solvent, continuing to cool to 50-70℃, adding diisocyanate dropwise, reacting at a temperature less than 100℃, continuing to heat after the dropwise addition is completed, adding the remaining raw materials after separating the solvent, and mixing to obtain the flame-retardant insulating paint for electric vehicle motors.

13. The method of claim 12, wherein: The method also comprises the steps of preparing the titanium dioxide nanotubes by hydrothermal reaction with anatase titanium dioxide powder, and preparing the modified titanium dioxide nanotubes by mixing the titanium dioxide nanotubes with an ethanol solution of the silane coupling agent and drying.

14. The flame-retardant insulating paint for electric vehicle motors of any one of claims 1-11 for use in insulating paint for electric vehicle motors.

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