High thermal conductivity and electrical insulation polymer material for motor stator and preparation method thereof

Abstract

The present invention provides a high thermal conductivity electrically insulating polymer material for motor stators and a preparation method thereof. The high thermal conductivity electrically insulating polymer material comprises an orderly arranged thermal conductive path skeleton composed of several inorganic fillers of predetermined sizes and predetermined shapes and a polymer material used to fill the gaps on the thermal conductive path skeleton and cured; the mass ratio of the inorganic filler to the polymer material is (50-90%): (10-50%). The present invention uses inorganic fillers of different sizes / different shapes as the skeleton substrate of the thermal conductive path to coordinate the thermal conductivity, and adopts a process of first arranging and stacking the inorganic fillers in an orderly manner, and then spraying and encapsulating with epoxy resin to effectively establish a shorter thermal conductive path to obtain the highest thermal conductivity effect, thereby preparing a stator material for fixing motor coils with high thermal conductivity, high strength and electrical insulation, and its performance is much higher than that of traditional thermal conductive materials, and has great application prospects in the field of motor stator materials.

Description

Technical Field

[0001] The present invention relates to the technical field of heat-conducting material preparation, and in particular to a high-heat-conducting and electrically insulating polymer material for a motor stator and a preparation method thereof. Background Art

[0002] In the prior art, a large amount of heat is generated when the motor is running. Overheating will affect the operating efficiency of the motor, affect the lubrication and insulation performance, and even cause burning. Due to the lack of good heat dissipation performance, heat accumulation causes the motor temperature to continue to rise, and the internal resistance of the motor will also increase, resulting in a sharp decline in the efficiency and function of the motor.

[0003] Traditional thermal conductive materials are mostly metals, metal oxides, metal nitrides and other non-metallic materials. The motor stator is equipped with a coil group, which requires an electrically insulating environment, and must have high dimensional stability when running at high speed. With the widespread application of motors, motors of various appearances and sizes have put forward higher requirements for stator materials, which must be easy to operate, can be processed arbitrarily, have better heat resistance and mechanical properties, and must ensure a small dimensional change rate. However, traditional thermal conductive materials can no longer meet the use requirements. The thermal conductivity of traditional filling materials is generally below 1w / mk, which cannot meet the needs of development in this field.

[0004] For example, the invention patent with publication number CN104788911A provides an epoxy resin composite material, its preparation method and application. The material is uniformly dispersed with 15% to 70% of inorganic filler by volume in epoxy resin, the inorganic filler includes large-particle inorganic filler and small-particle inorganic filler, the average particle size of the large-particle inorganic filler is between 2 microns and 50 microns, the average particle size of the small-particle inorganic filler is between 50nm and 500nm, and the volume ratio of the large-particle inorganic filler to the small-particle inorganic filler is between 5:5 and 9:1. Its preparation method includes the following steps: (1) taking large-particle inorganic filler and small-particle inorganic filler, fully drying and uniformly mixing to obtain a mixed filler; (2) adding the mixture to epoxy resin, uniformly dispersing, degassing and curing to obtain the epoxy resin composite material. However, this method has the defect that the spaces between the high thermal conductive fillers are filled with epoxy resin, the thermal resistance depends on the thickness of the epoxy layer, the larger the distance between the thermal conductive fillers, the lower the thermal conductivity coefficient, and because the system is a premixed system, no matter how much the fillers of different sizes are, they cannot be arranged in order to form the shortest thermal conductive path, and its thermal conductivity is far from meeting the needs of practical applications.

[0005] The invention patent with publication number CN107892898A provides a method for preparing a flame-retardant silicone potting compound with high thermal conductivity and low specific gravity. By surface treating and compounding different thermally conductive fillers, a graphene composite thermally conductive filler is prepared to improve the dispersion problem of the thermally conductive filler and the silicone rubber. The graphene composite thermally conductive filler can increase the thermal conductivity of the organic potting compound. By simulating different particle sizes and compounding with different particle sizes, the silicone potting compound has high thermal conductivity and low specific gravity. However, this method has the disadvantage that the motor has high requirements for resistivity, graphene is a good conductor of electricity, and the thermal resistance of the filling system is the same as the above reason analysis. The thermal conductivity depends on the silicone rubber between the discontinuous graphene, and it is impossible to achieve high thermal conductivity.

[0006] In view of this, it is necessary to design an improved high thermal conductivity and electrical insulation polymer material for motor stator and a preparation method thereof to solve the above problems. Summary of the invention

[0007] The object of the present invention is to provide a high thermal conductivity and electrical insulation polymer material for motor stators and a preparation method thereof.

[0008] To achieve the above-mentioned purpose, the present invention provides a high thermal conductivity and electrical insulation polymer material for a motor stator, which comprises an orderly arranged thermal conductive path skeleton composed of several inorganic fillers of predetermined sizes and shapes and a polymer material used to fill the gaps on the thermal conductive path skeleton and subjected to a curing treatment;

[0009] The mass ratio of the inorganic filler to the polymer material is (50-90%): (10-50%);

[0010] The high thermal conductivity and electrical insulation polymer material for the motor stator has a thermal conductivity of 1 to 30 W / mk and a volume resistivity of more than 10 12 Ω / cm 3 .

[0011] As a further improvement of the present invention, the shape of the inorganic filler is one or more combinations of columnar, spherical, irregular, and chopped fibers;

[0012] In the thermal conductive path skeleton, the mass ratio of the columnar inorganic filler, the spherical inorganic filler, the irregular inorganic filler and the chopped fiber inorganic filler is (1-50): (1-30): (1-40): (0-80).

[0013] As a further improvement of the present invention, the inorganic filler is a columnar particle or a columnar whisker with a length of 10 to 50 μm and a diameter of 5 to 10 μm, including but not limited to one or more combinations of silicon carbide, boron nitride, boron carbide and silicon nitride.

[0014] As a further improvement of the present invention, the inorganic filler is spherical particles with a particle size of 50 to 100 μm, including but not limited to one or more combinations of silicon carbide, boron nitride, boron carbide, silicon nitride, and aluminum oxide.

[0015] As a further improvement of the present invention, the inorganic filler is blocky irregular particles with a size of 200 to 500 μm, including but not limited to one or more combinations of silicon carbide, boron nitride, boron carbide, silicon nitride, and quartz.

[0016] As a further improvement of the present invention, the inorganic filler is chopped fibers with a length of 10 to 1000 mm and a diameter of 0.02 to 0.2 mm, including but not limited to one or more combinations of silicon carbide, boron nitride, boron carbide, silicon nitride, and quartz.

[0017] As a further improvement of the present invention, the polymer material is epoxy resin, and the polymer material is in liquid state before curing, and its viscosity at 25° C. is 2000-20000 mPa.s.

[0018] To achieve the above-mentioned object of the invention, the present invention also provides a method for preparing the above-mentioned high thermal conductivity and electrical insulation polymer material for motor stator, comprising the following steps:

[0019] S1, placing a columnar inorganic filler, a spherical inorganic filler, an irregular inorganic filler and a chopped fiber inorganic filler into a mold according to a predetermined ratio, and performing a vibration treatment to construct an orderly arranged heat conduction path skeleton;

[0020] S2, spraying the liquid polymer material into the mold until the inorganic filler is completely soaked, stopping the vibration treatment, and then heating the mold to 50-70° C. for curing treatment, so that the liquid polymer material is cross-linked and cured;

[0021] S3, after the curing treatment is completed, the cured polymer material is subjected to radiation treatment, and a high thermal conductivity and electrical insulation polymer material for a motor stator is prepared after the radiation is completed.

[0022] As a further improvement of the present invention, in step S1, the vibration direction of the vibration processing is a vertical direction.

[0023] As a further improvement of the present invention, in step S3, the radiation treatment process is: irradiation with a high-energy particle beam.

[0024] The beneficial effects of the present invention are:

[0025] 1. The high thermal conductivity and electrically insulating polymer material for motor stators provided by the present invention utilizes inorganic fillers of different sizes / shapes as the skeleton substrate of the thermal conductive path to coordinate the thermal conductivity. The inorganic fillers are first arranged and stacked in an orderly manner, and then sprayed and encapsulated with epoxy resin to effectively establish a shorter thermal conductive path to obtain the highest thermal conductivity effect, thereby preparing a stator material for fixing motor coils with high thermal conductivity, high strength and electrical insulation.

[0026] 2. The high thermal conductivity and electrical insulation polymer material for the motor stator provided by the present invention selects inorganic fillers of different shapes and sizes for compounding, and constructs an orderly arranged heat conduction path skeleton through orderly stacking, which can significantly shorten the heat conduction path and reduce the thermal resistance effect caused by the cavities that may exist in the material. The present invention combines the synergistic effect between inorganic fillers of different sizes / shapes and the orderly stacked skeleton structure constructed by the composite of inorganic fillers, which can significantly shorten the heat conduction path and improve the thermal conductivity of the material. Its mechanism of action is: heat is quickly extracted from the inside of the large-sized heat-conductive filler. In order to increase the heat dissipation stability and balance of the motor stator, the thermal resistance between the large-sized heat-conductive filler and the coil skeleton is reduced by using a smaller-sized heat-conductive filler, and the volume accumulation of the organic polymer with high cavity and thermal resistance is reduced. The various fillers are closely contacted by the process of the present invention, and the filler skeleton is fixed with organic matter to form a stable heat conduction path. The method provided by the present invention effectively overcomes the technical defects in the prior art: the ordinary mixing and stirring method is adopted, so that different types of inorganic fillers are randomly arranged and dispersed, and the required heat conduction path skeleton cannot be formed in the system, and the generation of thermal resistance effect cannot be avoided, which leads to the technical defect of poor thermal conductivity.

[0027] 3. The preparation method of the high thermal conductivity electrically insulating polymer material for motor stators provided by the present invention adopts a four-step combined process of vibration-spraying-heat curing-radiation to achieve the orderly arrangement and construction of the thermal conductive path, and through the two-step cross-linking treatment of curing cross-linking and strengthening cross-linking of the polymer material used for filling the gap, the strength and mechanical properties of the high thermal conductivity electrically insulating polymer material are significantly improved, and the gap filling and encapsulation effect of the polymer material is significantly enhanced, which is used to better fix the thermal conductive path, make the thermal conductive path orderly and stable, thereby significantly improving its thermal conductivity and thermal conductivity stability.

[0028] 4. The high thermal conductivity and electrical insulation polymer material for motor stator provided by the present invention has a thermal conductivity of 1 to 30w / mk and a volume resistivity of more than 10 12 Ω / cm 3 , which is far higher than the performance of thermal conductive materials prepared by traditional methods, and has great application prospects in the field of motor stator materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the cross-sectional structure of the high thermal conductivity and electrical insulation polymer material for motor stators provided by the present invention. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail with reference to specific embodiments below.

[0031] In addition, it should be noted that the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0032] The present invention provides a method for preparing a high thermal conductivity and electrical insulation polymer material for a motor stator, comprising the following steps:

[0033] S1, placing a columnar inorganic filler, a spherical inorganic filler, an irregular inorganic filler and a chopped fiber inorganic filler into a mold according to a predetermined ratio, performing a vibration treatment, and constructing an orderly arranged heat conduction path skeleton;

[0034] S2, spraying the liquid polymer material into the mold until the inorganic filler is completely soaked, stopping the vibration treatment, and then heating the mold to 50-70° C. for curing treatment, so that the liquid polymer material is cross-linked and cured;

[0035] S3, after the curing treatment is completed, the cured polymer material is subjected to radiation treatment, and a high thermal conductivity and electrical insulation polymer material for a motor stator is prepared after the radiation is completed.

[0036] As a further improvement of the present invention, in step S1, the vibration direction of the vibration processing is a vertical direction.

[0037] As a further improvement of the present invention, in step S3, the radiation treatment process is: irradiation with a high-energy particle beam.

[0038] The present invention will be further described in detail below with respect to specific implementation modes.

[0039] Example 1

[0040] Embodiment 1 of the present invention provides a method for preparing a high thermal conductivity and electrical insulation polymer material for a motor stator, comprising the following steps:

[0041] S1, placing the columnar inorganic filler 1, the spherical inorganic filler 2, the irregular inorganic filler 3 and the chopped fiber inorganic filler 4 into a mold according to a predetermined ratio, performing a vibration treatment, and constructing an orderly arranged heat conduction path skeleton. The specific process is as follows:

[0042] A mixture of boron nitride and silicon nitride columnar particles with a length of 20 μm and a diameter of 7 μm is used as inorganic filler 1, alumina spherical particles with a particle size of 100 μm are used as inorganic filler 2, and silicon carbide blocky irregular particles with a size of 400 μm are used as inorganic filler 3. A total of 850 grams is weighed at a mass ratio of 20: 20:45 and put into the mold of the embedded coil, and the vibration motor is turned on; the vibration direction is vertical.

[0043] S2, spraying the liquid polymer material into the mold until the inorganic filler is completely soaked, stopping the vibration treatment, and then heating the mold to 60° C. to perform a curing treatment so that the liquid polymer material is cross-linked and cured. The specific process is as follows:

[0044] Use a liquid metering pump to spray 150 grams of bisphenol A epoxy resin with a viscosity of 6000 onto the surface of the mixed inorganic filler through a porous nozzle. After the liquid epoxy resin is completely infiltrated into the inorganic filler system, turn off the vibration motor and move the mold to a 60°C oven for complete curing in 30 minutes.

[0045] S3, after the curing treatment is completed, the cured polymer material is subjected to radiation treatment, and a high-energy particle beam is used for irradiation. After the radiation is completed, a high thermal conductivity and electrical insulation polymer material (such as Figure 1 shown).

[0046] After testing, the thermal conductivity of the high thermal conductivity and electrical insulation polymer material for motor stator prepared in Example 1 is 15w / mk, and the volume resistivity is greater than 10 12 Ω / cm 3 .

[0047] Example 2

[0048] Embodiment 2 of the present invention provides a method for preparing a high thermal conductivity and electrical insulation polymer material for a motor stator, comprising the following steps:

[0049] S1, placing the columnar inorganic filler 1, the spherical inorganic filler 2, the irregular inorganic filler 3 and the chopped fiber inorganic filler 4 into a mold according to a predetermined ratio, performing a vibration treatment, and constructing an orderly arranged heat conduction path skeleton. The specific process is as follows:

[0050] A mixture of boron nitride columnar particles with a length of 10 μm and a diameter of 5 μm is used as inorganic filler 1, alumina spherical particles with a particle size of 50 μm are used as inorganic filler 2, silicon carbide blocky irregular particles with a size of 200 μm are used as inorganic filler 3, and short-cut silica glass fibers with a diameter of 0.05 mm are used as inorganic filler 4. The mass ratio is 10:10:15:25. A total of 3000 grams are weighed and put into the mold of the embedded coil, and the vibration motor is turned on; the vibration direction is vertical.

[0051] S2, spraying the liquid polymer material into the mold until the inorganic filler is completely soaked, stopping the vibration treatment, and then heating the mold to 60° C. to perform a curing treatment so that the liquid polymer material is cross-linked and cured. The specific process is as follows:

[0052] Use a liquid metering pump to spray 2000 grams of polyol epoxy resin with a viscosity of 12000 onto the surface of the mixed inorganic filler through a porous nozzle. After the liquid epoxy resin is completely infiltrated into the inorganic filler system, turn off the vibration motor and move the mold to a 60°C oven for complete curing in 30 minutes.

[0053] S3, after the curing treatment is completed, the cured polymer material is subjected to radiation treatment by irradiating with a high-energy particle beam, and a high thermal conductivity and electrical insulation polymer material for a motor stator is prepared after the radiation is completed.

[0054] After testing, the thermal conductivity of the high thermal conductivity and electrical insulation polymer material for motor stator prepared in Example 2 is 5w / mk, and the volume resistivity is greater than 10 12 Ω / cm 3 .

[0055] Embodiment 3-5

[0056] The difference from Example 2 is that the ratio between inorganic fillers, the ratio between inorganic fillers and polymer materials, and the setting of vibration process parameters are different, as shown in the following table.

[0057]

[0058]

[0059] According to the process parameters of the above embodiments 3 to 5, the prepared high thermal conductivity and electrical insulation polymer materials all have excellent thermal conductivity and electrical insulation properties.

[0060] Among them, the ratio between inorganic fillers and the ratio between inorganic fillers and polymer materials will have a certain impact on the composition structure of the thermal conductive path skeleton, and then affect the thermal conductivity and electrical insulation properties of the high thermal conductivity and electrical insulation polymer materials used in motor stators.

[0061] The vibration process parameters will have a certain impact on the construction of the orderly arrangement structure of the heat conduction path skeleton, and then affect the thermal conductivity and electrical insulation properties of the high thermal conductivity and electrical insulation polymer materials used in the motor stator.

[0062] In summary, the present invention provides a high thermal conductivity electrically insulating polymer material for motor stators and a preparation method thereof. The high thermal conductivity electrically insulating polymer material comprises an orderly arranged thermal conductive path skeleton composed of a plurality of inorganic fillers of predetermined sizes and predetermined shapes and a polymer material used to fill the gaps on the thermal conductive path skeleton and subjected to a curing treatment; the mass ratio of the inorganic filler to the polymer material is (50-90%): (10-50%). The present invention utilizes inorganic fillers of different sizes / different shapes as the skeleton substrate of the thermal conductive path to coordinate the thermal conductivity, and adopts a process of first arranging and stacking the inorganic fillers in an orderly manner, and then spraying and encapsulating with epoxy resin to fix them, which can effectively establish a shorter thermal conductive path to obtain the highest thermal conductive effect, thereby preparing a stator material for fixing motor coils with high thermal conductivity, high strength and electrical insulation.

[0063] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. A high thermal conductivity and electrical insulation polymer material for motor stator, characterized in that: The high thermal conductivity and electrical insulation polymer material for the motor stator comprises an orderly arranged thermal conductive path skeleton composed of several inorganic fillers of predetermined sizes and shapes and a polymer material used to fill the gaps in the thermal conductive path skeleton and subjected to curing and cross-linking treatment; The mass ratio of the inorganic filler to the polymer material is (50-90%): (10-50%); The high thermal conductivity and electrical insulation polymer material for the motor stator has a thermal conductivity of 15 to 30 W / mk and a volume resistivity of more than 10 12 Ω / cm 3 ; The polymer material is epoxy resin, which is in liquid state before curing, and has a viscosity of 2000-20000 mPa.s at 25°C; The method for preparing the high thermal conductivity and electrical insulation polymer material for the motor stator comprises the following steps: S1, placing a columnar inorganic filler, a spherical inorganic filler, an irregular inorganic filler and a chopped fiber inorganic filler into a mold according to a predetermined ratio, performing a vibration treatment, and constructing an orderly arranged heat conduction path skeleton; S2, spraying the liquid polymer material into the mold until the inorganic filler is completely soaked, stopping the vibration treatment, and then heating and curing the mold to make the liquid polymer material cross-linked and cured; S3, after the curing treatment is completed, the cured polymer material is subjected to radiation treatment, and after the radiation is completed, a high thermal conductivity and electrical insulation polymer material for a motor stator is prepared; In step S1, the vibration direction of the vibration processing is a vertical direction; The shape of the inorganic filler is one or more combinations of columnar, spherical, irregular, and chopped fibers; In the thermal conductive path skeleton, the mass ratio of the columnar inorganic filler, the spherical inorganic filler, the irregular inorganic filler and the chopped fibrous inorganic filler is (1-50): (1-30): (1-40): (0-80).

2. The high thermal conductivity and electrical insulation polymer material for motor stator according to claim 1, characterized in that: The inorganic filler is columnar particles or columnar whiskers with a length of 10 to 50 μm and a diameter of 5 to 10 μm. The inorganic filler is one or more combinations of silicon carbide, boron nitride, boron carbide and silicon nitride.

3. The high thermal conductivity and electrical insulation polymer material for motor stator according to claim 1, characterized in that: The inorganic filler is spherical particles with a particle size of 50 to 100 μm, and the inorganic filler is one or more combinations of silicon carbide, boron nitride, boron carbide, silicon nitride, and aluminum oxide.

4. The high thermal conductivity and electrical insulation polymer material for motor stator according to claim 1, characterized in that: The inorganic filler is blocky irregular particles with a size of 200 to 500 μm, and the inorganic filler is one or more combinations of silicon carbide, boron nitride, boron carbide, silicon nitride, and quartz.

5. The high thermal conductivity and electrical insulation polymer material for motor stator according to claim 1, characterized in that: The inorganic filler is short-cut fibers with a length of 10 to 1000 mm and a diameter of 0.02 to 0.2 mm, and the inorganic filler is one or more combinations of silicon carbide, boron nitride, boron carbide, silicon nitride, and quartz.

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