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

Abstract

The invention discloses a BMC (bulk molding compound) material and a preparation method and application thereof, the BMC material comprises 10-30 parts by weight of resin, 65-85 parts by weight of filler, 3-20 parts by weight of glass fiber, 0.05-1 part by weight of curing agent, 0.5-5 parts by weight of release agent, 0-1 part by weight of polymerization inhibitor and 0-5 parts by weight of glass beads, the curing agent is prepared from at least one of tert-butyl peroxyacetate, tert-amyl peroxybenzoate, tert-amyl peroxyacetate, tert-amyl peroxy-2-ethylhexanoate, tert-butyl peroxypivalate, tert-amyl peroxypivalate and bis (4-tert-butylcyclohexyl) peroxydicarbonate. The corrosion effect of the BMC material on the polyurethane 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.

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] At present, with the increasing maturity of motor R & D and manufacturing technologies, the miniaturization and lightweight of the motor body have become the mainstream development trends, which promote the continuous increase in the application scenarios of plastic encapsulated motors to gain more market shares. The BMC material belongs to a thermosetting polymer material and has excellent dimensional stability. This dimensional stability ensures that the deformation of the BMC material and the metal material is relatively synchronous under different temperature stresses, and it is very suitable for directly connecting with components with high dimensional precision requirements in the motor stator (such as end covers with bearing chambers, etc.). Moreover, for small-power household appliance motors, the insulation class is mostly between 130 and 220. Since the temperature resistance class of the 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 condition at most, while the BMC material can achieve low-temperature injection molding and is an excellent choice for the plastic encapsulation material of the motor stator. When the BMC material is used to encapsulate the motor stator, it is in direct contact with the stator enameled wire.

[0003] Generally, a plastic encapsulated motor uses a BMC material (bulk molding compound) to directly contact and encapsulate the enameled wire at high temperature. Both are thermosetting materials. After high-temperature curing, there are still incompletely cured organic substances and residual substances after the curing of the organic substances in the BMC material. Since both the BMC material and the enameled wire film in direct contact with it are polymers, there are some small-molecule substances remaining in the thermoset BMC material. These small-molecule substances continuously precipitate from the BMC material at high temperature and can effectively remove the film substances of the enameled wire. At the interface where the BMC material contacts the enameled wire, it corrodes the enameled wire. This corrosion effect intensifies continuously with the increase in the heat generation of the motor, resulting in inter-turn defects in the enameled wire. In severe cases, the film may even melt, break through the BMC material to cause the motor to jam or burn out. Therefore, there is an urgent need to use a low-corrosive BMC material to solve this contradiction. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems in the related technologies to some extent. For this purpose, the object of the present invention is to provide a BMC material, a preparation method thereof, and an application thereof. The present invention reduces the corrosion effect of the BMC material on the polyurethane enameled wire used in the motor stator. At the same time, the BMC material of the present invention has excellent high-temperature resistance, good fluidity, and mechanical strength.

[0005] In one aspect of the present invention, the present invention provides a BMC material. According to an embodiment of the present invention, the BMC material comprises: 10-30 parts by weight of resin, 65-85 parts by weight of filler, 3-20 parts by weight of glass fiber, 0.05-1 part by weight of curing agent, 0.5-5 parts by weight of release agent, 0-1 part by weight of inhibitor and 0-5 parts by weight of glass beads, and the curing agent comprises at least one of tert-butyl peroxyacetate, t-amyl peroxybenzoate, t-amyl peroxyacetate, t-amyl peroxy-2-ethylhexanoate, tert-butyl peroxy pivalate, t-amyl peroxy pivalate and bis(4-tert-butylcyclohexyl) peroxydicarbonate.

[0006] For the BMC material according to the 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 corrosivity, thereby reducing the corrosive effect of the BMC material on the polyurethane enameled wire of the stator for motors, enabling the BMC material to be applicable to the stator plastic encapsulation scenario of polyurethane enameled wire. Meanwhile, the present invention further reduces the corrosive effect of the BMC material on the polyurethane enameled wire of the stator for motors by controlling the ratio of each component in the BMC material. In addition, the BMC material of the present invention has excellent high-temperature resistance, good fluidity and mechanical strength.

[0007] In addition, the BMC material according to the above embodiment of the present invention may further have the following additional technical features:

[0008] In some embodiments of the present invention, the BMC material comprises: 15-25 parts by weight of the resin, 70-80 parts by weight of the filler, 5-12 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 release agent, 0.05-0.2 part by weight of the inhibitor and 0.2-2 parts by weight of the glass beads.

[0009] In some embodiments of the present invention, the resin comprises unsaturated polyester resin and anti-shrinkage resin, and the unsaturated polyester resin comprises at least one of styrene solutions of low acid value orthophthalic alkyd resin, styrene solutions of low acid value isophthalic alkyd resin and styrene solutions of low acid value vinyl resin.

[0010] In some embodiments of the present invention, the solid content of the unsaturated polyester resin is 50w%-80w%, and the acid value of the unsaturated polyester resin < 45mgKOH / g.

[0011] In some embodiments of the present invention, the mass ratio of the unsaturated polyester resin to the anti-shrinkage resin is 1:(1-4).

[0012] In some embodiments of the present invention, a first silane coupling agent is attached to the surface of the glass fiber, and the first silane coupling agent includes at least one of vinyl silane coupling agent, amino silane coupling agent, methacryloxy silane coupling agent, and mercapto silane coupling agent.

[0013] In some embodiments of the present invention, the diameter of the glass fiber is 1 μm - 25 μm, and the length of the glass fiber is 0.1 mm - 12 mm.

[0014] In some embodiments of the present invention, the glass microbeads are treated with a second silane coupling agent, and the second silane coupling agent includes at least one of vinyl silane coupling agent, amino silane coupling agent, methacryloxy silane coupling agent, and mercapto silane coupling agent; and / or, the diameter of the glass microbeads is 10 μm - 300 μm.

[0015] In some embodiments of the present invention, the filler includes at least one of aluminum hydroxide, alumina, aluminum nitride, magnesium hydroxide, carbon black, plastic, and calcium carbonate; and / or, the mold release agent includes at least one of zinc stearate, calcium stearate, and barium stearate; and / or, the polymerization inhibitor includes at least one of hydroquinone, benzoquinone, p-tert-butylcatechol, and quaternary ammonium salt.

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

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

[0018] (2) Mixing and stirring the filler and the glass microbeads 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 in the 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 polyurethane enameled wire of the stator for the motor, enabling the BMC material to be applicable to the polyurethane 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 polyurethane enameled wire of the stator for the motor, and endows the BMC material with excellent high-temperature resistance. In addition, this preparation method is simple and easy to implement, and is easy to be popularized.

[0022] In addition, the method according to the above embodiments of the present invention may further have the following additional technical features:

[0023] In some embodiments of the present invention, a first silane coupling agent is attached to the surface of the glass fiber. The preparation method of the glass fiber attached with the first silane coupling agent includes: during the cooling process after the glass fiber is drawn, immersing the drawn glass fiber in an alcohol solution, where the alcohol solution includes the first silane coupling agent, and performing a drying treatment after infiltration so that the first silane coupling agent is attached to the surface of the glass fiber. The first silane coupling agent includes at least one of vinyl silane coupling agent, amino silane coupling agent, methacryloxy silane coupling agent, and mercapto silane coupling agent.

[0024] In a third aspect of the present invention, the present invention provides a potted motor. According to the embodiments of the present invention, the potted motor is potted with the BMC material described in the above embodiments or the BMC material prepared by the method described in the above embodiments. Thereby, the corrosion effect of the BMC material on the polyurethane enameled wire of the stator of the potted motor is reduced, and at the same time, the high-temperature resistance performance of the potted motor is improved.

[0025] In some embodiments of the present invention, the potted motor includes a polyurethane enameled wire, and the BMC material after potted curing is in direct contact with the polyurethane enameled wire.

[0026] The additional aspects and advantages of the present invention will be given in part in the following description, will become apparent in part from the following description, or will be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] 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, where:

[0028] Figure 1 Schematic diagram of an enameled wire pair for testing the corrosion degree of the BMC material on the enameled wire by the breakdown voltage;

[0029] Figure 2 Schematic diagram of the sealed tube and the corresponding non-contact assembly structure used for evaluating the corrosion of the BMC material on the enameled wire. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, where 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 limiting the present invention.

[0031] In one aspect of the present invention, the present invention provides a BMC material. According to an embodiment of the present invention, the BMC material comprises: 10-30 parts by weight of resin, 65-85 parts by weight of filler, 3-20 parts by weight of glass fiber, 0.05-1 part by weight of curing agent, 0.5-5 parts by weight of mold release agent, 0-1 part by weight of polymerization inhibitor, and 0-5 parts by weight of glass microspheres. The curing agent comprises at least one of tert-butyl peroxyacetate, t-amyl peroxybenzoate, t-amyl peroxyacetate, t-amyl peroxydiethylhexanoate, tert-butyl peroxy pivalate, t-amyl peroxy pivalate, and bis(4-tert-butylcyclohexyl) peroxydicarbonate. Thus, the gas generated by the decomposition of the curing agent used in the present invention during the thermosetting molding process of the BMC material is non-corrosive or has low corrosivity, thereby reducing the corrosive effect of the BMC material on the polyurethane enameled wire of the stator for motors, and enabling the BMC material to be applicable to the stator plastic encapsulation scenario of polyurethane enameled wire. At the same time, the present invention further reduces the corrosive effect of the BMC material on the polyurethane enameled wire of the stator for motors by controlling the ratio of each component in the BMC material. In addition, the BMC material of the present invention has excellent high-temperature resistance.

[0032] The principle by which the BMC material proposed by the present invention can achieve the above beneficial effects will be described in detail below:

[0033] After the BMC encapsulates the motor, there are residual corrosive small-molecule substances in the thermoset BMC material. These corrosive small-molecule substances continuously precipitate from the BMC material under the heat of the motor and can remove the film substances of the enameled wire. The inventor's research found that such corrosive substances are mainly alcohols, acids, and hydrocarbons. These alcohols, acids, and hydrocarbons are uniformly dissolved in the styrene originally contained in the unsaturated polyester resin and not completely cross-linked, and have the function of removing paint. These small-molecule substances with the function of removing paint will cause slow damage to the film of the enameled wire when they are in a high-temperature environment for a long time, resulting in continuous occurrence of inter-turn defects during the use of the motor. Even worse, the BMC dissolves the film of the enameled wire until the film flows out of the BMC material in chunks, leading to phenomena such as motor burnout and jamming. Therefore, how to reduce the corrosive effect of the BMC material on the enameled wire has become an urgent problem to be solved. The inventor's research found that the above corrosive small-molecule substances are mainly generated by the decomposition of the curing agent in the BMC material during the curing process of the BMC material.

[0034] To solve the above problems, the present invention provides a novel BMC material. In this BMC material, an organic peroxide curing agent whose decomposition products are low-corrosive substances is adopted. Specifically, the curing agent includes at least one of tert-butyl peroxyacetate, t-amyl peroxybenzoate, t-amyl peroxyacetate, t-amyl peroxy-2-ethylhexanoate, tert-butyl peroxy pivalate, t-amyl peroxy pivalate, and bis(4-tert-butylcyclohexyl) peroxydicarbonate. The gases generated during the thermosetting molding process of the BMC material by the above types of curing agents are non-corrosive or have low corrosivity, thereby reducing the corrosive effect of the BMC material on the polyurethane enameled wire of the stator for motors, enabling the BMC material to be applicable to the scenario of plastic encapsulation of polyurethane enameled wire stators. Through reliability verification, the corrosivity of the BMC material of the present invention to polyurethane enameled wire is reduced by 80% compared to the current situation, effectively ensuring the long-term use safety of the motor. At the same time, the present invention further reduces the corrosive effect of the BMC material on the polyurethane enameled wire of the stator for motors by controlling the ratios of resin, curing agent, filler, mold release agent, glass fiber, glass microbeads, and inhibitor in the BMC material.

[0035] In addition, 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 polyurethane enameled wire of class 155. After plastic encapsulation with the BMC material of the present invention, it can meet the high-reliability use requirements of continuous use at 160 °C for more than 10,000 h without any problems such as inter-turn short circuit and withstand voltage.

[0036] According to some specific embodiments of the present invention, the BMC material includes: 15-25 parts by weight of resin, 70-80 parts by weight of filler, 5-12 parts by weight of glass fiber, 0.1-0.7 parts by weight of curing agent, 1-2 parts by weight of mold release agent, 0.05-0.2 parts by weight of inhibitor, and 0.2-2 parts by weight of glass microbeads. By limiting the component ratios of the BMC material within the above ranges, the corrosive effect of the BMC material on the polyurethane enameled wire of the stator for motors is further reduced, and the high-temperature resistance of the BMC material is further improved.

[0037] According to some other specific embodiments of the present invention, the resin includes unsaturated polyester resin and anti-shrinkage resin. The unsaturated polyester resin includes at least one of styrene solutions of low acid value orthophthalic alkyd resin, styrene solutions of low acid value isophthalic alkyd resin, and styrene solutions of low acid value vinyl resin. The above types of unsaturated polyester resins are all low acid value resins. By limiting the unsaturated polyester resins to be all low acid value resins, the corrosive gases generated during the thermosetting process of the BMC material can be further reduced, because the residual acid in the resin will increase the corrosivity of the resin itself.

[0038] According to some further specific embodiments of the present invention, the solid content of the unsaturated polyester resin can be 50 w%-80 w%, and the acid value of the unsaturated polyester resin is < 45 mgKOH / g. Thus, the corrosive gases generated during the thermal curing process of the BMC material are further reduced.

[0039] According to some further specific embodiments of the present invention, the mass ratio of the unsaturated polyester resin to the anti-shrinkage resin can be 1:(1 - 4).

[0040] In the embodiments of the present invention, the specific type of the above anti-shrinkage resin is not particularly limited. As some specific examples, the anti-shrinkage resin includes but is not limited to at least one of a styrene solution of a saturated polyester resin and a styrene solution of a low-density polyethylene resin.

[0041] In the embodiments of the present invention, the glass fiber mainly plays a reinforcing role in the BMC material. The glass fiber surface contains a large number of silanol groups, and such silanol groups have strong chemical polarity and weak chemical compatibility with the polyester resin. After the first silane coupling agent is attached to the glass fiber surface, during the curing process of the BMC (100 - 150 °C), the first silane coupling agent on the glass fiber surface dehydrates ethanol in the presence of water as follows:

[0042]

[0043] After the silanol groups in the first silane coupling agent after ethanol dehydration react with the silanol groups on the glass fiber surface and dehydrate, the first silane coupling agent is grafted onto the glass fiber surface. This not only has a chemical modification effect on the glass fiber, enabling better chemical contact between the glass fiber and the BMC material, but also allows the glass fiber and the resin to form a -Si-O-Si-O- bond (as shown below), enhancing the mechanical strength and toughness of the BMC material.

[0044]

[0045] In the embodiments of the present invention, the specific type of the above first silane coupling agent is not particularly limited. As some specific examples, the first silane coupling agent includes but is not limited to at least one of a vinyl silane coupling agent, an amino silane coupling agent, a methacryloxy silane coupling agent, and a mercapto silane coupling agent.

[0046] According to some further specific embodiments of the present invention, the diameter of the glass fiber is 1 μm - 25 μm, and the length of the glass fiber is 0.1 mm - 12 mm. Thus, the surface area of the glass fiber is further increased, thereby increasing the first silane coupling agent attached to the glass fiber surface, and further enhancing the mechanical strength and toughness of the BMC material.

[0047] In an embodiment of the present invention, the glass microspheres themselves 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. However, if the lubricating effect is too good, the physical strength of the BMC material will be attenuated. Therefore, in some embodiments, the glass microspheres can be treated with a second silane coupling agent. Treating the glass microspheres with the second silane coupling agent can cause a chemical reaction between the BMC material and the glass microspheres during the crosslinking process after injection molding, thereby enhancing the physical strength of the BMC material.

[0048] The specific process of treating the glass microspheres with the second silane coupling agent can be as follows: The pickled and dried glass microspheres are immersed in an ethanol solution containing 6 wt% vinyl silane coupling agent, stirred at 20 - 60 °C for 0.5 - 2 h, and then dried to ensure complete volatilization of the ethanol solution, obtaining the glass microspheres treated by coupling.

[0049] In an embodiment of the present invention, the specific type of the above-mentioned second silane coupling agent is not particularly limited. As some specific examples, the second silane coupling agent includes, but is not limited to, at least one of vinyl silane coupling agent, amino silane coupling agent, methacryloxy silane coupling agent, and mercapto silane coupling agent.

[0050] According to some other specific embodiments of the present invention, the diameter of the glass microspheres can be 10 μm - 300 μm. The glass microspheres of the present invention can be hollow glass microspheres or solid glass microspheres.

[0051] 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, aluminum nitride, magnesium hydroxide, carbon black, plastic, and calcium carbonate. As a preferred solution, the filler includes calcium carbonate, aluminum hydroxide, alumina, and aluminum nitride; as another preferred solution, the filler includes calcium carbonate and aluminum hydroxide, and the mass ratio of calcium carbonate to aluminum hydroxide is (40 - 65):(10 - 25).

[0052] 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.

[0053] 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.

[0054] In yet 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:

[0055] S100: Mix and stir the resin, inhibitor, curing agent, and mold release agent to obtain a first mixture.

[0056] In this step, the resin, inhibitor, curing agent, and mold 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 minutes.

[0057] S200: Mix and stir the filler and glass beads to obtain a second mixture.

[0058] 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.

[0059] S300: Mix and stir the first mixture and the second mixture to obtain a third mixture.

[0060] In this step, the first mixture can be added to a kneader and mixed and stirred with the second mixture to obtain a uniformly mixed paste (i.e., the third mixture).

[0061] S400: Mix and stir the third mixture and glass fiber to obtain a BMC material.

[0062] 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.

[0063] According to some specific embodiments of the present invention, the surface of the glass fiber is attached with a first silane coupling agent. The preparation method of the glass fiber attached with the first silane coupling agent includes:

[0064] During the cooling process after glass fiber drawing, the drawn glass fiber is immersed in an alcohol solution (such as ethanol solution), and the alcohol solution includes the first silane coupling agent. After infiltration, it is dried to ensure that the ethanol solvent volatilizes completely, so that the first silane coupling agent is attached to the surface of the glass fiber. The first silane coupling agent includes at least one of vinyl silane coupling agent, amino silane coupling agent, methacryloxy silane coupling agent, and mercapto silane coupling agent. By attaching the first silane coupling agent to the surface of the glass fiber, the mechanical strength of the BMC material is further enhanced in the present invention.

[0065] According to still some other specific embodiments of the present invention, the mass concentration of the first silane coupling agent in the alcohol solution is 2wt% - 10wt%. Thus, by limiting the concentration of the first silane coupling agent in the alcohol solution within the above range, it is ensured that the first silane coupling agent attached to the surface of the glass fiber can reach a saturated state.

[0066] 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 gas with no corrosion or low corrosion during the thermosetting molding process of the BMC material, thereby reducing the corrosion effect of the BMC material on the polyurethane enameled wire of the stator for the motor, enabling the BMC material to be applicable to the stator plastic encapsulation scenario of the polyurethane enameled wire. Meanwhile, by controlling the ratio of each component in the BMC material, this method further reduces the corrosion effect of the BMC material on the polyurethane enameled wire of the stator for the motor, and endows the BMC material with excellent high-temperature resistance performance. In addition, this preparation method is simple and easy to implement, and is easy to be popularized.

[0067] 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 of the above embodiment or the BMC material prepared by the method of the above embodiment. Thereby, the corrosion effect of the BMC material on the polyurethane enameled wire of the stator of the plastic encapsulated motor is reduced, and at the same time, the high-temperature resistance performance of the plastic encapsulated motor is improved.

[0068] Specifically, the plastic encapsulated motor includes a stator, and an enameled wire is wound around the stator. In the present invention, a polyurethane type enameled wire is used, and the BMC material after plastic encapsulation and curing is in direct contact with the polyurethane type enameled wire.

[0069] The stator winding modes include two types: distributed winding and straight winding. The above-mentioned polyurethane enameled wire includes straight-welding type polyurethane enameled copper wire, non-straight-welding type polyurethane enameled copper wire, straight-welding type polyurethane enameled aluminum wire, non-straight-welding type polyurethane enameled aluminum wire, and polyurethane composite film enameled copper wire, enameled aluminum wire and copper-clad aluminum (or aluminum-plated copper) enameled wire with polyurethane as the main component such as polyurethane / nylon, polyurethane / lubricating oil or silicone oil. The above-mentioned enameled wire includes enameled round wire and enameled flat wire.

[0070] The 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. In addition, if not specified explicitly, all reagents used in the following embodiments are commercially available, or can be synthesized according to the methods described in this article or known methods. For the reaction conditions not listed, they are also easily obtained by those skilled in the art.

[0071] Example 1

[0072] This embodiment provides a BMC material, which includes: a styrene solution of 13 parts by weight of a low acid value orthophthalic alkyd resin, a styrene solution of 5 parts by weight of a saturated resin, 53.6 parts by weight of calcium carbonate, 20 parts by weight of aluminum hydroxide, 7 parts by weight of glass fiber treated by coupling, 1.1 parts by weight of zinc stearate, 0.1 part by weight of benzoquinone, 0.15 part by weight of t-amyl peroxyacetate, and 0.05 part by weight of bis(4-tert-butylcyclohexyl) peroxydicarbonate. Among them, the acid value of the styrene solution of the low acid value orthophthalic alkyd resin is 35 mgKOH / g, and the solid content is 60%.

[0073] The preparation method of the BMC material includes:

[0074] 1) Put the above-mentioned low acid value orthophthalic alkyd resin, styrene solution, zinc stearate, benzoquinone, t-amyl peroxyacetate, and bis(4-tert-butylcyclohexyl) peroxydicarbonate into a disperser and stir for 10 min to obtain a uniformly mixed liquid;

[0075] 2) Add calcium carbonate and aluminum hydroxide to a kneader and stir evenly to obtain a uniformly mixed filler;

[0076] 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;

[0077] 4) Add the glass fiber treated by coupling to the obtained paste and knead evenly at 30 °C to obtain the BMC material.

[0078] Among them, the length of the glass fiber is 3 mm and the diameter is 2 μm. The specific process of coupling treatment of the glass fiber is as follows: during the cooling process after glass fiber drawing, immerse the drawn glass fiber in an ethanol solution containing 6 wt% vinyl silane coupling agent, and after infiltration, perform drying treatment to ensure that the ethanol solution volatilizes completely to obtain the glass fiber treated by coupling.

[0079] Example 2

[0080] This embodiment provides a BMC material, which includes: a styrene solution of 13 parts by weight of a low acid value orthophthalic alkyd resin, a styrene solution of 6 parts by weight of a saturated resin, 0.53 parts by weight of hollow glass microspheres, 55.3 parts by weight of calcium carbonate, 16 parts by weight of aluminum hydroxide, 8 parts by weight of glass fiber treated by coupling, 0.8 parts by weight of zinc stearate, 0.1 part by weight of benzoquinone, 0.18 part by weight of bis(4-tert-butylcyclohexyl) peroxydicarbonate, and 0.09 part by weight of tert-butyl peroxyacetate. Among them, the acid value of the styrene solution of the low acid value orthophthalic alkyd resin is 25 mgKOH / g, and the solid content is 70%.

[0081] The preparation method of the BMC material includes:

[0082] 1) Put the above low acid value o-phthalic alkyd resin, styrene solution, zinc stearate, benzoquinone, bis(4-tert-butylcyclohexyl) peroxydicarbonate and tert-butyl peroxyacetate into a disperser and stir for 10 min to obtain a uniformly mixed liquid;

[0083] 2) Add calcium carbonate, aluminum hydroxide and hollow glass microspheres to a kneader and stir evenly to obtain a uniformly mixed filler;

[0084] 3) Put the uniformly mixed liquid in step 1) into a kneader and mix and stir with the uniformly mixed filler to obtain a uniformly mixed paste;

[0085] 4) Add the glass fiber treated by coupling treatment to the obtained paste and knead evenly at 30 °C to obtain the BMC material.

[0086] Among them, the length of the glass fiber is 6 mm and the diameter is 10 μm. The specific process of coupling treatment of the glass fiber is as follows: during the cooling process after the glass fiber is drawn, the drawn glass fiber is immersed in an ethanol solution containing 6 wt% vinyl silane coupling agent, and after infiltration, it is dried to ensure that the ethanol solution volatilizes completely to obtain the glass fiber treated by coupling treatment.

[0087] Example 3

[0088] This example provides a BMC material, which includes: 13.35 parts by weight of a styrene solution of a low acid value m-phthalic alkyd resin, 6 parts by weight of a styrene solution of a saturated resin, 0.3 parts by weight of hollow glass microspheres, 55 parts by weight of calcium carbonate, 15.8 parts by weight of aluminum hydroxide, 8 parts by weight of the glass fiber treated by coupling treatment, 1.2 parts by weight of zinc stearate, 0.05 parts by weight of benzoquinone, 0.3 parts by weight of tert-amyl peroxy-2-ethylhexanoate. Among them, the length of the glass fiber is 10 mm and the diameter is 20 μm. Among them, the acid value of the styrene solution of the low acid value m-phthalic alkyd resin is 25 mgKOH / g, and the solid content is 70%.

[0089] Other contents are the same as those in Example 2.

[0090] Example 4

[0091] This embodiment provides a BMC material, which includes: 15 parts by weight of a styrene solution of a low acid value m-phthalic alkyd resin, 5 parts by weight of a styrene solution of a saturated resin, 1 part by weight of hollow glass microspheres, 50 parts by weight of calcium carbonate, 22 parts by weight of aluminum hydroxide, 5 parts by weight of glass fibers treated by coupling, 1.5 parts by weight of zinc stearate, 0.1 part by weight of benzoquinone, 0.2 part by weight of tert-butyl perpivalate, and 0.2 part by weight of tert-amyl peroxybenzoate. Among them, the length of the glass fibers is 10 mm and the diameter is 20 μm. Among them, the acid value of the styrene solution of the low acid value m-phthalic alkyd resin is 25 mgKOH / g and the solid content is 70%.

[0092] All other contents are the same as those in Embodiment 2.

[0093] Embodiment 5

[0094] This embodiment provides a BMC material, which includes: 14 parts by weight of a styrene solution of a low acid value m-phthalic alkyd resin, 8 parts by weight of a styrene solution of a saturated resin, 0.5 part by weight of hollow glass microspheres, 45.5 parts by weight of calcium carbonate, 20 parts by weight of aluminum hydroxide, 10 parts by weight of glass fibers treated by coupling, 1.7 parts by weight of zinc stearate, 0.1 part by weight of benzoquinone, 0.1 part by weight of bis(4-tert-butylcyclohexyl) peroxydicarbonate, and 0.1 part by weight of tert-amyl peroxy pivalate. Among them, the length of the glass fibers is 10 mm and the diameter is 20 μm. Among them, the acid value of the styrene solution of the low acid value m-phthalic alkyd resin is 25 mgKOH / g and the solid content is 70%.

[0095] All other contents are the same as those in Embodiment 2.

[0096] Embodiment 6

[0097] This embodiment provides a BMC material. The difference between this embodiment and Embodiment 2 is only that:

[0098] The glass microspheres in this embodiment have been treated with a silane coupling agent. The specific process is as follows: The pickled and dried glass microspheres are immersed in an ethanol solution containing 6 wt% of vinyl silane coupling agent, stirred at 40 °C for 1 h, and then dried to ensure that the ethanol solution has completely volatilized, obtaining the glass microspheres treated by coupling.

[0099] All other contents are the same as those in Embodiment 2.

[0100] Comparative Example 1

[0101] This comparative example provides a BMC material, which includes raw materials with the following weight percentages: unsaturated resin (styrene solution of phthalic acid resin) 12%, low shrinkage resin (styrene solution of saturated resin) 5%, mold release agent (zinc stearate) 1.1%, curing agent (tert-butyl peroxy-2-ethylhexanoate) 0.1%, curing agent (tert-butyl peroxybenzoate) 0.2%, chopped glass fiber 7%, calcium carbonate 60.5%, aluminum hydroxide 14%, and inhibitor (benzoquinone) 0.1%.

[0102] The preparation method is the same as that of Example 1.

[0103] The flame retardancy, fluidity, and notched Izod impact strength of the BMC materials prepared in Examples 1-6 and Comparative Example 1 were tested respectively, and the test results are shown in Table 1.

[0104] The non-contact corrosion verification of the BMC materials prepared in Examples 1-6 and Comparative Example 1 was carried out using sealed tubes respectively, 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 polyurethane enameled wire. A sealed tube with a volume of 0.8L was used, and 24 cm 3 The cured BMC sample block and the polyurethane enameled wire stranded pair placed in parallel in the sealed tube and not in contact with the sealed tube wall were used, as Figure 2 shown. After the sealed tube was placed in a high-temperature oven for a period of time, the breakdown voltage test of the polyurethane enameled wire stranded pair was carried out, as Figure 1 shown. The breakdown voltage tests were carried out on the polyurethane enameled wire stranded pair without corrosion treatment, the cured BMC materials of Examples 1-6 and Comparative Example 1 stored non-contact in a sealed tube at 160°C for 10000 h respectively, and the breakdown voltage attenuation rate was calculated. The results are shown in Table 1.

[0105] Table 1

[0106]

[0107] It can be seen from Table 1 that compared with Comparative Example 1, the breakdown voltage attenuation rates of Examples 1-6 are significantly reduced, indicating that the corrosivity of the BMC materials of Examples 1-6 to polyurethane enameled wire is significantly reduced. And compared with Comparative Example 1, the fluidity and flexural strength of the BMC materials of Examples 1-6 are significantly improved. It can be seen that the embodiments of the present invention can improve the reliability of the long-term operation of the motor under the conditions of ensuring fluidity, good injection molding, and high mechanical strength.

[0108] In the description of this specification, the descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean 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 may be combined in any one or more embodiments or examples in a suitable manner. 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.

[0109] 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, characterized in that, it comprises: 10 - 30 parts by weight of resin, 65 - 85 parts by weight of filler, 3 - 20 parts by weight of glass fiber, 0.05 - 1 part by weight of curing agent, 0.5 - 5 parts by weight of release agent, 0 - 1 part by weight of inhibitor, and 0 - 5 parts by weight of glass microspheres, wherein the curing agent comprises at least one of tert-butyl peroxyacetate, t-amyl peroxybenzoate, t-amyl peroxyacetate, t-amyl peroxy-2-ethylhexanoate, tert-butyl peroxy pivalate, t-amyl peroxy pivalate, and bis(4-tert-butylcyclohexyl) peroxydicarbonate.

2. The BMC material according to claim 1, characterized in that, it comprises: 15 - 25 parts by weight of the resin, 70 - 80 parts by weight of the filler, 5 - 12 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 release agent, 0.05 - 0.2 part by weight of the inhibitor, and 0.2 - 2 parts 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 unsaturated polyester resin comprises at least one of styrene solution of low acid value orthophthalic alkyd resin, styrene solution of low acid value isophthalic alkyd resin, and styrene solution of low acid value vinyl resin.

4. The BMC material according to claim 3, characterized in that, the solid content of the unsaturated polyester resin is 50w% - 80w%, and the acid value of the unsaturated polyester resin < 45mgKOH / g.

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

6. The BMC material according to claim 1, characterized in that, the surface of the glass fiber is attached with a first silane coupling agent, and the first silane coupling agent comprises at least one of vinyl silane coupling agent, amino silane coupling agent, methacryloxy silane coupling agent, and mercapto silane coupling agent.

7. The BMC material according to claim 6, characterized in that, the diameter of the glass fiber is 1μm - 25μm, and the length of the glass fiber is 0.1mm - 12mm.

8. The BMC material according to any one of claims 1 - 7, characterized in that, the glass microspheres are treated with a second silane coupling agent, and the second silane coupling agent comprises at least one of vinyl silane coupling agent, amino silane coupling agent, methacryloxy silane coupling agent, and mercapto silane coupling agent; and / or, the diameter of the glass microspheres is 10μm - 300μm.

9. The BMC material according to any one of claims 1 - 7, characterized in that, the filler comprises at least one of aluminum hydroxide, alumina, aluminum nitride, magnesium hydroxide, carbon black, plastic, and calcium carbonate; and / or, the release agent comprises at least one of zinc stearate, calcium stearate, and barium stearate; and / or, the inhibitor comprises at least one of hydroquinone, benzoquinone, p-tert-butylcatechol, and quaternary ammonium salt.

10. A method for preparing the BMC material according to any one of claims 1-9, characterized in that, comprising: (1) Mixing and stirring a resin, an inhibitor, a curing agent and a mold release agent to obtain a first mixture; (2) Mixing and stirring a filler and glass beads to obtain a second mixture; (3) Mixing and stirring the first mixture and the second mixture to obtain a third mixture; (4) Mixing and stirring the third mixture and glass fibers to obtain the BMC material.

11. The BMC material according to claim 10, characterized in that, a first silane coupling agent is attached to the surface of the glass fibers, and the method for preparing the glass fibers attached with the first silane coupling agent comprises: During the cooling process after the glass fibers are drawn, the drawn glass fibers are immersed in an alcohol solution, the alcohol solution contains a first silane coupling agent, and after infiltration, drying treatment is carried out so that the first silane coupling agent is attached to the surface of the glass fibers, and the first silane coupling agent includes at least one of a vinyl silane coupling agent, an amino silane coupling agent, a methacryloxy silane coupling agent and a mercapto silane coupling agent.

12. A plastic-sealed motor, characterized in that, it is plastic-sealed with the BMC material according to any one of claims 1-9 or the BMC material prepared by the method according to claim 10 or 11.

13. The plastic-sealed motor according to claim 12, characterized in that, it includes a polyurethane enameled wire, and the BMC material after plastic-sealing and curing is in direct contact with the polyurethane enameled wire.

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