BMC (bulk molding compound) material as well as preparation method and application thereof

Abstract

The invention discloses a BMC (bulk molding compound) material as well as a preparation method and application thereof. The BMC material comprises the following components in parts by weight: 15-25 parts of resin, 65-85 parts of filler, 5-20 parts of glass fiber, 0.1-1 part of a curing agent, 0.5-2 parts of a release agent, 0.05-0.3 part of a polymerization inhibitor and 0-1 part of glass beads. The curing agent is an organic peroxide curing agent, and gas generated by decomposition of the curing agent in the thermosetting forming process of the BMC material is non-corrosive or relatively low in corrosion, so that the corrosion effect of the BMC material on the polyester enameled wire of the stator for the motor is reduced. Meanwhile, the BMC material disclosed by the invention has excellent high-temperature resistance, good flowability and mechanical strength, and realizes low cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of motor plastic encapsulation materials, and particularly relates to a BMC material, a preparation method thereof, and an application thereof. Background Art

[0002] The requirements of people for high performance of motor products drive the development of motors towards miniaturization, safety, low noise, and low cost. With the development and progress of composite materials, plastic-encapsulated motors gradually occupy an increasing market share. The BMC material has good strength, stiffness, electrical insulation performance, dimensional stability, and can be used for a long time in harsh environments. The BMC material for low-temperature injection molding is very suitable for replacing steel and used as the motor housing, and can directly plastic-encapsulate the bearing chamber end cover with relatively high dimensional requirements. For small-power household appliance motors, the insulation class is mostly between 130 and 220, and the temperature resistance class of its enameled wire is relatively low. It is required that the plastic encapsulation material can only be injection molded at a temperature lower than the insulation class. The BMC material can achieve low-temperature injection molding, which is an excellent choice for the stator plastic encapsulation material in plastic-encapsulated motors.

[0003] However, with the increasingly wide application range of plastic-encapsulated motors, their use reliability is also severely tested. Plastic-encapsulated motors generally use BMC material (bulk molding compound) to directly contact and plastic-encapsulate the enameled wire at high temperature. Both are thermosetting materials. After high-temperature curing, there are still incompletely cured organic substances remaining in the BMC material. The residues in the BMC material or their decomposition products at high temperature contain low-molecular components such as hydrocarbons, alcohols, ethers, and ketones that can effectively corrode or remove the enameled wire film. Over time, they will continuously precipitate from the BMC material, contact the enameled wire, and corrode the enameled wire film. Especially when the motor runs at high temperature for a long time, the corrosion effect is aggravated, resulting in poor inter-turn and withstand voltage of the enameled wire, and even causing the motor to burn out in severe cases.

[0004] Small-power household motors mainly use polyurethane-type, polyester-type, and polyesterimide-type enameled wires. Compared with polyurethane-type and polyesterimide-type enameled wires, the polyester-type enameled wire has a high ester bond content and strong bond energy, can withstand high temperature and corrosion, and has a relatively low cost. It is the mainstream enameled wire for household motors. However, the enameled wire film of the polyester-type enameled wire will still be corroded by the highly corrosive BMC material, reducing the reliability of its plastic-encapsulated motor products. Therefore, it is urgent to use a low-corrosion BMC material to solve this problem. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems in the related art to some extent. To this end, the object of the present invention is to provide a BMC material, a preparation method and an application thereof. The present invention reduces the corrosive effect of the BMC material on the polyester enameled wire of the stator for motors. At the same time, the BMC material of the present invention has excellent high-temperature resistance, good fluidity and mechanical strength, and realizes low cost.

[0006] In one aspect of the present invention, a BMC material is provided, and the BMC material is used for encapsulating a motor with polyester enameled wire. According to an embodiment of the present invention, the BMC material includes: 15-25 parts by weight of resin, 65-85 parts by weight of filler, 5-20 parts by weight of glass fiber, 0.1-1 part by weight of curing agent, 0.5-2 parts by weight of mold release agent, 0.05-0.3 part by weight of polymerization inhibitor, and 0-1 part by weight of glass microspheres. The curing agent includes at least one of 1,1-di-tert-butylperoxycyclohexane, 1,1-di-tert-amylperoxycyclohexane, tert-butyl peroxy-2-ethylhexyl carbonate, di-tert-butyl peroxide, tert-butyl peroxyisononanoate, 2,5-di-tert-butylperoxy-2,5-dimethylhexane, tert-butyl peroxyacetate, tert-amyl peroxy-2-ethylhexanoate, tert-butyl peroxy pivalate, tert-amyl peroxy pivalate, bis(4-tert-butylcyclohexyl) peroxydicarbonate, and tert-butyl peroxyneodecanoate.

[0007] For the BMC material according to an embodiment of the present invention, the gas generated by the decomposition of the curing agent used during the thermosetting molding of the BMC material is non-corrosive or has low corrosiveness, thereby reducing the corrosive effect of the BMC material on the polyester enameled wire of the stator for motors, enabling the BMC material to be applicable to the scenario of encapsulating polyester enameled wire stators. At the same time, the present invention further reduces the corrosive effect of the BMC material on the polyester enameled wire of the stator for motors by controlling the ratio of each component in the BMC material, and ensures that the BMC material of the present invention has excellent high-temperature resistance under the condition of ensuring fluidity and good injection molding process conditions. In addition, the present invention realizes low cost by increasing the content of the filler in the BMC material and reducing the resin content while ensuring that the mechanical strength of the BMC material remains unchanged.

[0008] In addition, the BMC material according to the above embodiment of the present invention may further have the following additional technical features:

[0009] In some embodiments of the present invention, the BMC material includes: 15-25 parts by weight of the resin, 70-80 parts by weight of the filler, 5-10 parts by weight of the glass fiber, 0.1-0.5 part by weight of the curing agent, 1-2 parts by weight of the mold release agent, 0.05-0.2 part by weight of the polymerization inhibitor, and 0.2-1 part by weight of the glass microspheres.

[0010] In some embodiments of the present invention, the resin includes an unsaturated polyester resin and an anti-shrinkage resin, and the mass ratio of the unsaturated polyester resin to the anti-shrinkage resin is 1:(1 - 4).

[0011] In some embodiments of the present invention, the unsaturated polyester resin includes at least one of an orthophthalic alkyd resin, an isophthalic alkyd resin, a vinyl resin, and an epoxy resin.

[0012] In some embodiments of the present invention, the anti-shrinkage resin includes at least one of a saturated polyester resin, a low-density polyethylene resin, and a polystyrene resin.

[0013] In some embodiments of the present invention, the filler includes at least one of aluminum hydroxide, alumina, magnesium hydroxide, and calcium carbonate; and / or, the mold release agent includes at least one of zinc stearate, calcium stearate, and barium stearate.

[0014] In some embodiments of the present invention, the inhibitor includes at least one of hydroquinone, benzoquinone, p-tert-butylcatechol, and quaternary ammonium salts; and / or, the glass fiber includes non-alkali chopped glass fibers.

[0015] In some embodiments of the present invention, the BMC material further includes: 0 - 1 part by weight of a thickener.

[0016] In another aspect of the present invention, the present invention provides a method for preparing the above-mentioned BMC material. According to the embodiments of the present invention, the method includes:

[0017] (1) Mixing and stirring the resin, inhibitor, curing agent, and mold release agent to obtain a first mixture;

[0018] (2) Mixing and stirring the filler and glass beads to obtain a second mixture;

[0019] (3) Mixing and stirring the first mixture and the second mixture to obtain a third mixture;

[0020] (4) Mixing and stirring the third mixture and the glass fiber to obtain the BMC material.

[0021] According to the method for preparing the above BMC material according to an embodiment of the present invention, the curing agent used decomposes to generate gases with no or low corrosiveness during the thermosetting molding process of the BMC material, thereby reducing the corrosive effect of the BMC material on the polyester enameled wire of the stator for the motor, enabling the BMC material to be applicable to the polyester enameled wire stator plastic encapsulation scenario. Meanwhile, by controlling the ratio of each component in the BMC material, this method further reduces the corrosive effect of the BMC material on the polyester enameled wire of the stator for the motor, and ensures that the BMC material of the present invention has excellent high-temperature resistance under the condition of ensuring fluidity and good injection molding process conditions. In addition, by increasing the content of the filler in the BMC material and reducing the resin content, cost reduction is achieved on the premise of ensuring the mechanical strength of the BMC material remains unchanged. Moreover, this preparation method is simple and easy to implement, and is easy to be popularized.

[0022] In the third aspect of the present invention, the present invention proposes a plastic encapsulated motor. According to an embodiment of the present invention, the plastic encapsulated motor is plastic encapsulated using the BMC material described in the above embodiments or the BMC material prepared by the method described in the above embodiments. Thereby, the corrosive effect of the BMC material on the polyester enameled wire of the stator of the plastic encapsulated motor is reduced, and at the same time, the high-temperature resistance of the plastic encapsulated motor is improved, thus enhancing the reliability of the long-term operation of the motor.

[0023] The additional aspects and advantages of the present invention will be partially given in the following description, partially become apparent from the following description, or be understood through the practice of the present invention. Brief Description of the Drawings

[0024] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, wherein:

[0025] Figure 1 Schematic diagram of an enameled wire stranded pair for testing the corrosion degree of the BMC material on the enameled wire by breakdown voltage;

[0026] Figure 2 Schematic diagram of a sealed tube and a corresponding non-contact assembly structure used to evaluate the corrosion of the BMC material on the enameled wire. Detailed Description of the Embodiments

[0027] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention, and should not be construed as a limitation of the present invention.

[0028] In one aspect of the present invention, a BMC material is proposed, and the BMC material is used for encapsulating a motor with polyester enameled wire. According to an embodiment of the present invention, the BMC material comprises 15-25 parts by weight of resin, 65-85 parts by weight of filler, 5-20 parts by weight of glass fiber, 0.1-1 part by weight of curing agent, 0.5-2 parts by weight of mold release agent, 0.05-0.3 part by weight of polymerization inhibitor, and 0-1 part by weight of glass microspheres. The curing agent includes at least one of 1,1-di-tert-butylperoxycyclohexane, 1,1-di-tert-amylperoxycyclohexane, tert-butyl peroxy-2-ethylhexyl carbonate, di-tert-butyl peroxide, tert-butyl peroxyisononanoate, 2,5-di-tert-butylperoxy-2,5-dimethylhexane, tert-butyl peroxyacetate, tert-pentyl peroxy-2-ethylhexanoate, tert-butyl peroxy pivalate, tert-pentyl peroxy pivalate, bis(4-tert-butylcyclohexyl) peroxydicarbonate, and tert-butyl peroxyneodecanoate. Thus, the curing agent adopted in the present invention decomposes to generate gases with no or low corrosivity during the thermosetting process of the BMC material, thereby reducing the corrosive effect of the BMC material on the polyester enameled wire of the stator for the motor, and enabling the BMC material to be applicable to the scenario of encapsulating the stator with polyester enameled wire. At the same time, by controlling the ratio of each component in the BMC material, the present invention further reduces the corrosive effect of the BMC material on the polyester enameled wire of the stator for the motor, and ensures that the BMC material of the present invention has excellent high-temperature resistance under the condition of ensuring fluidity and good injection molding process. In addition, by increasing the content of the filler in the BMC material and reducing the resin content, the present invention realizes low cost on the premise of ensuring the mechanical strength of the BMC material unchanged.

[0029] The principle by which the BMC material proposed by the present invention can achieve the above beneficial effects will be described in detail below:

[0030] Generally, for encapsulating a motor, a BMC material (bulk molding compound) is directly contacted with and plastically encapsulated the enameled wire at high temperature. Both are thermosetting materials. After high-temperature curing, there are still incompletely cured organic matters remaining in the BMC material. The residues in the BMC material or their decomposition products at high temperature contain low-molecular components such as hydrocarbons, alcohols, ethers, and ketones that can effectively corrode or remove the enamel film of the enameled wire, and will continuously precipitate from the BMC material over time, contact with the enameled wire, and corrode the enamel film of the enameled wire. Especially when the motor runs at high temperature for a long time, the corrosion effect is aggravated, resulting in defects such as inter-turn and withstand voltage of the enameled wire, and even burning out of the motor in severe cases. Therefore, there is an urgent need to use a BMC material with low corrosivity to solve this problem. The inventor has found through research that the above-mentioned corrosive low-molecular components are mainly generated by the decomposition of the curing agent in the BMC material during the curing process of the BMC material.

[0031] To solve the above problems, the present invention provides a novel BMC material. In this BMC material, a curing agent whose decomposition products contain no or relatively little corrosive substances such as acids and alcohols is used. This curing agent is an organic peroxide curing agent. Specifically, the curing agent includes at least one of 1,1 - di - tert - butylperoxycyclohexane, 1,1 - di - tert - amylperoxycyclohexane, tert - butyl peroxy - 2 - ethylhexyl carbonate, di - tert - butyl peroxide, tert - butyl peroxyisononanoate, 2,5 - di - tert - butylperoxy - 2,5 - dimethylhexane, tert - butyl peroxyacetate, tert - amyl peroxy - 2 - ethylhexanoate, tert - butyl peroxy pivalate, pivaloyl peroxide, bis(4 - tert - butylcyclohexyl) peroxydicarbonate, and tert - butyl peroxyneodecanoate. The gases generated during the thermosetting molding process of the above - mentioned type of BMC material are non - corrosive or have low corrosivity, thereby reducing the corrosive effect of the BMC material on the polyester enameled wire of the stator for motors, enabling the BMC material to be applicable to the stator plastic encapsulation scenario of polyester enameled wire. Through reliability verification, the corrosivity of the BMC material of the present invention to polyester enameled wire is reduced by 80% compared with the current situation, effectively ensuring the long - term use safety of the motor. At the same time, by controlling the ratios of resin, curing agent, filler, mold release agent, glass fiber, glass microbeads, and inhibitor in the BMC material, the present invention further reduces the corrosive effect of the BMC material on the polyester enameled wire of the stator for motors.

[0032] In addition, by controlling the ratios of resin, curing agent, filler, mold release agent, glass fiber, glass microbeads, and inhibitor in the BMC material, the present invention ensures that the BMC material of the present invention has excellent high - temperature resistance. Under the condition of ensuring fluidity and good injection molding process conditions, it can be used for 155 - grade polyester enameled wire. After plastic encapsulation with the BMC material of the present invention, it can meet the high - reliability use requirements of continuous use at 155°C for more than 20,000 h without problems such as inter - turn short - circuit and breakdown voltage.

[0033] Moreover, by increasing the content of the filler in the BMC material and reducing the resin content, the present invention achieves low - cost while ensuring the mechanical strength of the BMC material remains unchanged.

[0034] According to some specific embodiments of the present invention, the BMC material comprises: 15-25 parts by weight of resin, 70-80 parts by weight of filler, 5-10 parts by weight of glass fiber, 0.1-0.5 parts by weight of curing agent, 1-2 parts by weight of demolding agent, 0.05-0.2 parts by weight of polymerization inhibitor, and 0.2-1 parts by weight of glass microspheres. By limiting the component ratio of the BMC material within the above range, the corrosive effect of the BMC material on the polyester enameled wire of the stator for motors is further reduced, and under the condition of ensuring fluidity and good injection molding process conditions, the BMC material of the present invention is further ensured to have excellent high-temperature resistance performance. In particular, by reducing the content of the curing agent, the corrosive effect of the BMC material on the polyester enameled wire of the stator for motors is further reduced.

[0035] According to still some specific embodiments of the present invention, the resin comprises unsaturated polyester resin and anti-shrinkage resin, and the mass ratio of the unsaturated polyester resin to the anti-shrinkage resin is 1:(1-4).

[0036] In the embodiments of the present invention, the specific type of the above-mentioned unsaturated polyester resin is not particularly limited. As some specific examples, the unsaturated polyester resin may include, but is not limited to, at least one of orthophthalic alkyd resin, isophthalic alkyd resin, vinyl resin, and epoxy resin. For example, it may include at least one of low acid value orthophthalic alkyd resin, high acid value isophthalic alkyd resin, high acid value vinyl resin, and high acid value epoxy resin. The polyester enameled wire has relatively good corrosion resistance and has no specific requirement for acid value. Using unsaturated polyester resins with high or low acid values can meet the corrosive requirements. Therefore, the above-mentioned unsaturated polyester resin can be of high acid value or low acid value. Preferably, it is at least one of low acid value orthophthalic alkyd resin, high acid value vinyl resin, and high acid value epoxy resin.

[0037] In the embodiments of the present invention, the specific type of the above-mentioned anti-shrinkage resin is not particularly limited. As some specific examples, the anti-shrinkage resin includes at least one of saturated polyester resin, low density polyethylene resin, and polystyrene resin.

[0038] In the embodiments of the present invention, the glass fiber mainly plays a reinforcing role in the BMC material. As a preferred solution, the glass fiber can be selected as alkali-free chopped glass fiber. More preferably, the alkali-free chopped glass fiber with its surface treated with silane coupling agent is selected. The silane coupling agent can strengthen the bonding between the glass fiber and the resin matrix. Thus, the mechanical strength of the BMC material is further enhanced.

[0039] In the embodiments of the present invention, the glass microspheres can improve the fluidity of the BMC material. Improving the fluidity can enhance the injection molding effect of the BMC material on complex products, making the injection molded products more plump and defect-free. The glass microspheres of the present invention can be hollow glass microspheres or solid glass microspheres.

[0040] In an embodiment of the present invention, the specific type of the above-mentioned filler is not particularly limited. As some specific examples, the filler includes but is not limited to at least one of aluminum hydroxide, alumina, magnesium hydroxide, and calcium carbonate. As a preferred solution, the filler includes calcium carbonate and aluminum hydroxide, and the mass ratio of calcium carbonate to aluminum hydroxide is (45 - 60):(15 - 25).

[0041] In an embodiment of the present invention, the specific type of the above-mentioned release agent is not particularly limited. As some specific examples, the release agent includes but is not limited to at least one of zinc stearate, calcium stearate, and barium stearate.

[0042] In an embodiment of the present invention, the specific type of the above-mentioned polymerization inhibitor is not particularly limited. As some specific examples, the polymerization inhibitor includes but is not limited to at least one of hydroquinone, benzoquinone, p-tert-butylcatechol, and quaternary ammonium salts.

[0043] According to some other specific embodiments of the present invention, the BMC material may further include: 0 - 1 part by weight of a thickening agent, and the thickening agent has the function of adjusting the fluidity of the BMC material. The specific type of the thickening agent is not particularly limited. As some specific examples, the thickening agent includes but is not limited to magnesium oxide.

[0044] In another aspect of the present invention, the present invention provides a method for preparing the above-mentioned BMC material. According to an embodiment of the present invention, the method includes:

[0045] S100: Mix and stir the resin, polymerization inhibitor, curing agent, and release agent to obtain a first mixture

[0046] In this step, the resin, polymerization inhibitor, curing agent, and release agent can be placed in a disperser and stirred for a period of time to obtain a uniformly mixed first mixture. The stirring time is not particularly limited as long as the components are uniformly mixed. For example, it can be stirred for 10 min.

[0047] S200: Mix and stir the filler and glass beads to obtain a second mixture

[0048] In this step, the filler and glass beads can be added to a kneader and stirred evenly to obtain a second mixture. The stirring time is also not particularly limited as long as the components are uniformly mixed.

[0049] For the BMC material including a thickening agent, the thickening agent is also mixed in this step, that is, the filler, glass beads, and thickening agent are added to a kneader and stirred evenly to obtain a second mixture.

[0050] S300: Mix and stir the first mixture and the second mixture to obtain a third mixture

[0051] In this step, the first mixture can be added to a kneader and mixed with the second mixture to obtain a uniformly mixed paste (i.e., the third mixture).

[0052] S400: Mix and stir the third mixture and glass fiber to obtain a BMC material

[0053] In this step, glass fiber can be added to the paste uniformly mixed in step S300 and kneaded evenly under the condition of 10 - 50 °C to obtain a BMC material.

[0054] According to the method for preparing the above BMC material according to the embodiments of the present invention, the curing agent used decomposes to generate gases with no or low corrosiveness during the thermosetting molding process of the BMC material, thereby reducing the corrosive effect of the BMC material on the polyester enameled wire of the stator for motors, enabling the BMC material to be applicable to the polyester enameled wire stator plastic encapsulation scenario. At the same time, by controlling the ratio of each component in the BMC material, this method further reduces the corrosive effect of the BMC material on the polyester enameled wire of the stator for motors, and ensures that the BMC material of the present invention has excellent high-temperature resistance under the condition of ensuring fluidity and good injection molding process conditions. In addition, by increasing the content of the filler in the BMC material, the resin content is reduced, achieving low cost on the premise of keeping the mechanical strength of the BMC material unchanged. And this preparation method is simple and easy to implement, and is easy to be popularized.

[0055] In the third aspect of the present invention, the present invention proposes a plastic encapsulated motor. According to the embodiments of the present invention, the plastic encapsulated motor is plastic encapsulated with the BMC material of the above embodiments or the BMC material prepared by the method of the above embodiments, and the plastic encapsulated motor includes polyester type enameled wire, and the BMC material after plastic encapsulation curing is in direct contact with the polyester type enameled wire. Thus, the corrosive effect of the BMC material on the polyester enameled wire of the stator of the plastic encapsulated motor is reduced, and at the same time, the high-temperature resistance of the plastic encapsulated motor is improved, thereby enhancing the reliability of the long-term operation of the motor.

[0056] Specifically, the plastic encapsulated motor includes a stator, and an enameled wire is wound around the stator. In the present invention, polyester type enameled wire is used, and the BMC material after plastic encapsulation curing is in direct contact with the polyester type enameled wire.

[0057] The stator winding mode includes two types: the distributed winding type of an AC motor and the direct winding of a DC motor. The above enameled wire includes polyester type enameled wire or a composite film enameled wire related to polyester. The above stator winding includes at least one of copper wire, aluminum wire, and metal wires with copper plating, alloy plating, and coating layers. The above enameled wire includes at least one of enameled round wire and enameled flat wire.

[0058] Embodiments of the present invention will be described in detail below. It should be noted that the embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as a limitation to the present invention. Additionally, if not specified otherwise, all reagents used in the following embodiments are commercially available or can be synthesized according to the methods described herein or known methods. Reaction conditions not listed are also easily obtainable by those skilled in the art.

[0059] Example 1

[0060] This example provides a BMC material, which includes: 12 parts by weight of orthophthalic alkyd resin, 5 parts by weight of low-density polyethylene resin, 53.8 parts by weight of calcium carbonate, 21 parts by weight of aluminum hydroxide, 6.8 parts by weight of glass fiber, 1 part by weight of zinc stearate, 0.1 part by weight of benzoquinone, 0.1 part by weight of 1,1-di-tert-butylperoxycyclohexane, and 0.2 part by weight of 1,1-di-tert-pentylperoxycyclohexane.

[0061] The preparation method of the BMC material includes:

[0062] 1) Place the above-mentioned orthophthalic alkyd resin, low-density polyethylene resin, zinc stearate, benzoquinone, 1,1-di-tert-butylperoxycyclohexane, and 1,1-di-tert-pentylperoxycyclohexane into a disperser and stir for 10 min to obtain a uniformly mixed liquid;

[0063] 2) Add calcium carbonate and aluminum hydroxide to a kneader and stir evenly to obtain a uniformly mixed filler;

[0064] 3) Put the uniformly mixed liquid in step 1) into the kneader and mix and stir with the uniformly mixed filler to obtain a uniformly mixed paste;

[0065] 4) Add glass fiber to the obtained paste and mix evenly under the condition of 30 °C to obtain the BMC material.

[0066] Example 2

[0067] This example provides a BMC material, which includes: 13 parts by weight of orthophthalic alkyd resin, 6 parts by weight of low-density polyethylene resin, 0.5 part by weight of hollow glass microspheres, 51.3 parts by weight of calcium carbonate, 20 parts by weight of aluminum hydroxide, 7.6 parts by weight of glass fiber, 1.2 parts by weight of zinc stearate, 0.1 part by weight of benzoquinone, 0.2 part by weight of tert-butyl peroxy-2-ethylhexyl carbonate, and 0.1 part by weight of tert-butyl peroxyisononanoate.

[0068] The preparation method of the BMC material includes:

[0069] 1) Place the above phthalic alkyd resin, low-density polyethylene resin, zinc stearate, benzoquinone, tert-butyl peroxy-2-ethylhexyl carbonate, and tert-butyl peroxynonanoate into a disperser and stir for 10 min to obtain a uniformly mixed liquid;

[0070] 2) Add calcium carbonate, aluminum hydroxide, and hollow glass microspheres to a kneader and stir evenly to obtain a uniformly mixed filler;

[0071] 3) Put the uniformly mixed liquid in step 1) into the kneader and mix and stir with the uniformly mixed filler to obtain a uniformly mixed paste;

[0072] 4) Add glass fiber to the obtained paste and knead evenly at 30 °C to obtain a BMC material.

[0073] Example 3

[0074] This example provides a BMC material, which includes: 13 parts by weight of isophthalic alkyd resin, 6 parts by weight of low-density polyethylene resin, 0.5 part by weight of hollow glass microspheres, 51.4 parts by weight of calcium carbonate, 20 parts by weight of aluminum hydroxide, 7.6 parts by weight of glass fiber, 1.2 parts by weight of zinc stearate, 0.1 part by weight of benzoquinone, and 0.2 part by weight of 2,5-di-tert-butylperoxy-2,5-dimethylhexane.

[0075] The preparation method of the BMC material is the same as that of Example 2.

[0076] Example 4

[0077] This example provides a BMC material, which includes: 14 parts by weight of phthalic alkyd resin, 4 parts by weight of styrene solution, 1 part by weight of hollow glass microspheres, 58.1 parts by weight of calcium carbonate, 16 parts by weight of aluminum hydroxide, 5 parts by weight of glass fiber, 1.4 parts by weight of zinc stearate, 0.1 part by weight of benzoquinone, 0.2 part by weight of tert-butyl peroxy-2-ethylhexyl carbonate, and 0.2 part by weight of tert-butyl peroxypivalate.

[0078] The preparation method of the BMC material is the same as that of Example 2.

[0079] Example 5

[0080] This embodiment provides a BMC material, which includes: 14.45 parts by weight of m-phthalic alkyd resin, 8 parts by weight of styrene solution, 0.5 part by weight of hollow glass microspheres, 40 parts by weight of calcium carbonate, 25 parts by weight of aluminum hydroxide, 10 parts by weight of glass fiber, 1.7 parts by weight of zinc stearate, 0.15 part by weight of benzoquinone, 0.1 part by weight of bis(4-tert-butylcyclohexyl) peroxydicarbonate, and 0.1 part by weight of t-amyl peroxy-2-ethylhexanoate.

[0081] The preparation method of the BMC material is the same as that of Example 2.

[0082] Comparative Example 1

[0083] This comparative example provides a BMC material, including the following raw materials in parts by weight: 13 parts by weight of o-phthalic alkyd resin, 5 parts by weight of low shrinkage resin (low density polyethylene resin), 0.9 part by weight of mold release agent (zinc stearate), 0.8 part by weight of curing agent (tert-butyl peroxybenzoate), 1.4 parts by weight of curing agent (tert-butyl peroxy-2-ethylhexanoate), 6.7 parts by weight of chopped glass fiber, 52 parts by weight of calcium carbonate, 20 parts by weight of aluminum hydroxide, and 0.2 part by weight of inhibitor (benzoquinone).

[0084] The preparation method is the same as that of Example 1.

[0085] The flame retardancy, fluidity, and flexural strength of the BMC materials prepared in Examples 1-5 and Comparative Example 1 were tested respectively, and the test results are shown in Table 1.

[0086] The non-contact corrosion verification of the BMC materials prepared in Examples 1-5 and Comparative Example 1 was carried out using sealed tubes, that is, the non-electrical insulation system verification scheme in the UL insulation system, which can quantify the corrosion effect of the BMC material on polyester enameled wire. A 0.8L sealed tube was used, and 24 cm 3 The cured BMC sample block and the polyester enameled wire stranded wire pair placed in parallel in the sealed tube and not in contact with the sealed tube wall were as Figure 2 shown. After the sealed tube was placed in a high-temperature box for a period of time, the breakdown voltage test was carried out on the polyester enameled wire stranded wire pair, as Figure 1 shown. The breakdown voltage tests were carried out on the polyester enameled wire stranded wire pair without corrosion treatment, and the polyester enameled wire stranded wires of the cured BMC materials in Examples 1-5 and Comparative Example 1 stored non-contact in a 155°C sealed tube for 20000 h respectively, and the breakdown voltage attenuation rate was calculated. The results are shown in Table 1.

[0087] Table 1

[0088]

[0089] As can be seen from Table 1, compared with Comparative Example 1, the breakdown voltage attenuation rates of Examples 1-5 are significantly reduced, indicating that the corrosivity of the BMC materials in Examples 1-5 to polyester enameled wires is significantly reduced. Moreover, compared with Comparative Example 1, the fluidity, tensile strength, and flexural strength of the BMC materials in Examples 1-5 are all significantly improved. It can be seen that the embodiments of the present invention can achieve an improvement in the long-term operation reliability of the motor under the conditions of ensuring fluidity, good injection molding, and high mechanical strength.

[0090] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0091] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A BMC material, which is used for encapsulating a motor with polyester enameled wire. Characterized in that: The BMC material comprises: 15 - 25 parts by weight of resin, 65 - 85 parts by weight of filler, 5 - 20 parts by weight of glass fiber, 0.1 - 1 part by weight of curing agent, 0.5 - 2 parts by weight of mold release agent, 0.05 - 0.3 part by weight of inhibitor, and 0 - 1 part by weight of glass microspheres. The curing agent comprises at least one of 1,1 - di - tert - butylperoxycyclohexane, 1,1 - di - tert - amylperoxycyclohexane, tert - butyl peroxy - 2 - ethylhexyl carbonate, di - tert - butyl peroxide, tert - butyl peroxyisononanoate, 2,5 - di - tert - butylperoxy - 2,5 - dimethylhexane, tert - butyl peroxyacetate, tert - amyl peroxy - 2 - ethylhexanoate, tert - butyl peroxy pivalate, pivaloyl peroxide, bis(4 - tert - butylcyclohexyl) peroxydicarbonate, tert - butyl peroxyneodecanoate.

2. The BMC material according to claim 1, Characterized in that: Comprises: 15 - 25 parts by weight of the resin, 70 - 80 parts by weight of the filler, 5 - 10 parts by weight of the glass fiber, 0.1 - 0.5 part by weight of the curing agent, 1 - 2 parts by weight of the mold release agent, 0.05 - 0.2 part by weight of the inhibitor, and 0.2 - 1 part by weight of the glass microspheres.

3. The BMC material according to claim 1, Characterized in that: The resin comprises unsaturated polyester resin and anti - shrinkage resin, and the mass ratio of the unsaturated polyester resin to the anti - shrinkage resin is 1:(1 - 4).

4. The BMC material according to claim 3, Characterized in that: The unsaturated polyester resin comprises at least one of orthophthalic alkyd resin, isophthalic alkyd resin, vinyl resin and epoxy resin.

5. The BMC material according to claim 3, Characterized in that: The anti - shrinkage resin comprises at least one of saturated polyester resin, low - density polyethylene resin and polystyrene resin.

6. The BMC material according to any one of claims 1 - 5, Characterized in that: The filler comprises at least one of aluminum hydroxide, alumina, magnesium hydroxide and calcium carbonate; And / or, the mold release agent comprises at least one of zinc stearate, calcium stearate and barium stearate.

7. The BMC material according to any one of claims 1 - 5, Characterized in that: The inhibitor comprises at least one of hydroquinone, benzoquinone, p - tert - butylcatechol and quaternary ammonium salt; And / or, the glass fiber comprises non - alkali chopped glass fiber.

8. The BMC material according to any one of claims 1 - 5, Characterized in that: Further comprises: 0 - 1 part by weight of thickener.

9. A method for preparing the BMC material according to any one of claims 1 - 8, Characterized in that: Comprises: (1) Mixing and stirring the resin, inhibitor, curing agent and mold release agent to obtain a first mixture; (2) Mixing and stirring the filler and glass microspheres to obtain a second mixture; (3) Mixing and stirring the first mixture and the second mixture to obtain a third mixture; (4) Mix and stir the third mixture and glass fiber to obtain the BMC material.

10. A plastic-encapsulated motor, characterized in that it is plastic-encapsulated with the BMC material described in any one of claims 1-8 or the BMC material prepared by the method described in claim 9, and the plastic-encapsulated motor includes polyester enameled wire, and the BMC material after plastic-encapsulation curing is in direct contact with the polyester enameled wire.

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