Acoustic package for new energy automobile electric drive system and preparation method of acoustic package

Abstract

The invention relates to the technical field of NVH (Noise Vibration and Harshness) control of an electric drive system of a new energy automobile, and discloses an acoustic bag for the electric drive system of the new energy automobile, which is characterized by comprising a sound absorption layer and a composite sound insulation layer, the composite sound insulation layer is an EPM (Ethylene-Propylene-Metallic) rubber layer with two sides covered with PET (Polyethylene Terephthalate) non-woven fabrics, and the sound absorption layer is a foaming PU (Polyurethane) layer; the double-faced PET-coated non-woven fabric comprises a first PET non-woven fabric layer and a second PET non-woven fabric layer, the EPM rubber layer is coated with the first PET non-woven fabric layer, and the first PET non-woven fabric layer makes contact with the foaming PU layer and is used for improving the bonding strength of the EPM rubber layer and the foaming PU layer; and the second PET non-woven fabric layer covers the outer surface of the EPM rubber layer and is used for improving the surface scratch resistance and improving the supporting property of the acoustic bag after high-temperature aging. According to the acoustic bag, by improving the structural design and material combination, the defects of a traditional acoustic bag in the aspects of interface bonding strength, tensile formability and supporting performance after high-temperature aging are effectively overcome.

Description

Technical Field

[0001] This invention relates to the field of NVH control technology for electric drive systems of new energy vehicles, specifically to an acoustic package for electric drive systems of new energy vehicles and its preparation method. Background Technology

[0002] The electric drive system of new energy vehicles generates broadband noise during operation. To reduce the impact of noise on occupants, acoustic packages consisting of sound insulation and sound absorption layers are typically used. In existing technologies, sound insulation layers often use EPDM / EPM / EVA with a single-sided PET nonwoven fabric cover, while sound absorption layers often use foamed PU (polyurethane). While EPM with a single-sided PET nonwoven fabric cover has good sound insulation performance, its tensile formability is poor. During molding, areas with large deformation are easily torn. In subsequent foaming processes, the foamed PU easily penetrates the EPM under high pressure, causing overflow defects. Furthermore, the interfacial bonding strength between EPM and foamed PU is insufficient, making it prone to interface separation during installation and application, affecting acoustic performance. It is also prone to collapse after high-temperature aging, leading to a decrease in the overall support of the acoustic package.

[0003] A search revealed CN119568029A, which discloses an acoustic package for a motor in new energy vehicles. This package includes a polyurethane foam layer and a polyester fiber layer disposed on the polyurethane foam layer. The polyester fiber layer comprises a surface carpet, polyester staple fiber felt, and a polypropylene / polyamide composite membrane arranged sequentially. Compared to existing technologies, this acoustic package offers advantages such as lighter weight, higher strength, better heat resistance, and better acoustic performance. However, this technology does not solve the aforementioned problem of insufficient interfacial bonding strength between the EPM and the foamed PU.

[0004] Therefore, there is an urgent need for a new type of acoustic package that can overcome the above-mentioned defects in order to improve the NVH performance and reliability of electric drive systems in new energy vehicles. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention discloses an acoustic package for electric drive systems in new energy vehicles. This acoustic package effectively overcomes the deficiencies of traditional acoustic packages in terms of interfacial bonding strength, tensile formability, and support after high-temperature aging by improving structural design and material combination.

[0006] This invention employs a double-sided PET nonwoven fabric-coated EPM rubber layer as the sound insulation layer. The first PET nonwoven fabric layer directly contacts the foamed PU layer, significantly enhancing the adhesion between them and effectively preventing overflow caused by the foamed PU penetrating the EPM layer under high pressure. The second PET nonwoven fabric layer covers the outer surface of the EPM rubber layer, improving the scratch resistance of the acoustic package surface and maintaining good support after high-temperature aging, preventing the entire acoustic package from collapsing. The sound-absorbing layer is a foamed PU layer, working synergistically with the sound insulation layer to significantly improve the NVH performance of the electric drive system in new energy vehicles.

[0007] Furthermore, by precisely controlling the component ratio and preparation process parameters of the EPM rubber layer, such as the mixing pressure, time, and temperature, the temperature, pressure, and production line speed of hot pressing, as well as the conditions of key steps such as molding and high-pressure foaming, the present invention ensures the stability and reliability of the acoustic package, providing a more superior acoustic solution for the electric drive system of new energy vehicles.

[0008] The technical means adopted by the present invention to solve the above problems are as follows: An acoustic package for an electric drive system of a new energy vehicle is disclosed, comprising a sound-absorbing layer and a sound-insulating layer. The sound-insulating layer is an EPM rubber layer with double-sided PET nonwoven fabric, and the sound-absorbing layer is a foamed PU layer. The double-sided PET nonwoven fabric includes a first PET nonwoven fabric layer and a second PET nonwoven fabric layer. The first PET nonwoven fabric layer covers the EPM rubber layer and is in contact with the foamed PU layer to improve the bonding strength between the EPM rubber layer and the foamed PU layer. The second PET nonwoven fabric layer covers the outer surface of the EPM rubber layer to improve surface scratch resistance and enhance the support of the acoustic package after high-temperature aging.

[0009] The acoustic package for the electric drive system of new energy vehicles of this invention changes the traditional concept of single-sided PET nonwoven fabric covering by double-sided covering the sound insulation layer with PET nonwoven fabric. This not only enhances the interfacial bonding strength between the EPM rubber layer and the foamed PU layer, effectively preventing PU material overflow during foaming, but also significantly improves the overall structural stability and durability of the acoustic package. Especially under high-temperature aging conditions, the addition of the second PET nonwoven fabric layer provides additional support for the acoustic package, preventing collapse caused by material softening, thereby ensuring the performance consistency of the acoustic package during long-term use.

[0010] Further, the EPM rubber layer is composed of the following components by weight: POE: 20-50 parts, LLDPE: 5-10 parts, thermoplastic rubber: 5-10 parts, magnesium hydroxide: 15-30 parts, aluminum hydroxide: 15-30 parts, barium sulfate: 15-30 parts, calcium carbonate: 15-30 parts, rubber oil: 3-8 parts, carbon black: 1-5 parts, stearic acid: 1-5 parts, antioxidant: 1-5 parts.

[0011] This invention optimizes the composition ratio of the EPM rubber layer, selects various polymer materials such as POE, LLDPE, and thermoplastic rubber, and rationally adds inorganic fillers such as magnesium hydroxide and aluminum hydroxide, as well as additives such as rubber oil and carbon black. This not only improves the physical and mechanical properties of the EPM rubber layer, such as tensile strength and tear strength, but also improves its processing performance, making the acoustic package easier to operate and control during the preparation process.

[0012] Another object of the present invention is to disclose a method for preparing the above-mentioned acoustic package, comprising the following steps: S1.EPM rubber mixing: In the internal mixer, add POE, LLDPE, thermoplastic rubber, magnesium hydroxide, aluminum hydroxide, barium sulfate, calcium carbonate, rubber oil, carbon black, stearic acid, and antioxidant in sequence according to the formula ratio, and start the internal mixer. S2. While extruding the EPM rubber layer, hot-press the first PET nonwoven fabric layer and the second PET nonwoven fabric layer onto both sides to form a PET / EPM / PET three-layer composite layer. S3. Place the PET / EPM / PET three-layer composite material in the molding die, with the first PET nonwoven fabric layer facing the bottom of the die; S4. Place the molded PET / EPM / PET three-layer composite material into a foaming mold, with the first PET non-woven fabric layer facing the bottom of the mold, inject PU foaming material, and perform high-pressure foaming to firmly bond the foamed PU layer with the first PET non-woven fabric layer, forming a PET / EPM / PET / PU four-layer composite acoustic package. S5. Water jet cutting and assembly to obtain an EPM / PU acoustic package with double-sided PET nonwoven fabric covering of the desired shape.

[0013] Furthermore, the mixing pressure is 4 kg to 10 kg, the mixing time is 20 min to 40 min, and the mixing ends when the temperature inside the mixer is controlled at 120℃ to 180℃.

[0014] Furthermore, in step S2, the temperature of the hot pressing composite is 140℃~220℃, the pressure is 0.3MPa~0.7MPa, the temperature is 8℃~20℃, and the production line speed is 2m / min~6m / min.

[0015] Furthermore, the thickness of the EPM rubber layer is 0.5mm~3.0mm, and the areal density is 2000~4000g / m³. 2 .

[0016] Furthermore, the basis weight of the first PET nonwoven fabric layer is 70g / m²~110g / m², the basis weight of the second PET nonwoven fabric layer is 90g / m²~130g / m², and the density of the foamed PU is 50g / m²~90kg / m³.

[0017] Furthermore, in step S3, the heating temperature for compression molding is 210℃~240℃, the heating time is 70S~110S, and the holding time is 80S~120S.

[0018] Furthermore, the mold temperature for the high-pressure foaming is 50℃~90℃, the foaming time is 60S~90S, and the foaming pressure is 50Kg~90kg.

[0019] Furthermore, in step S5, the water pressure for water cutting is 8MPa~13MPa, the air pressure is 0.2MPa~0.9MPa, and the water temperature of the chiller is 15℃~30℃.

[0020] In terms of manufacturing process, this invention employs a series of advanced technologies such as intensive mixing, hot pressing, molding, and high-pressure foaming. By precisely controlling the process parameters of each step, such as the intensive mixing pressure, time, and temperature; the hot pressing temperature, pressure, and production line speed; and the heating temperature, time, and pressure of molding and high-pressure foaming, the tight bonding between the layers of the acoustic package and the uniformity of its overall performance are ensured.

[0021] In summary, the acoustic package for electric drive systems of new energy vehicles and its preparation method of the present invention, through innovative structural design and material selection, combined with precise manufacturing process control, effectively solves the problems of insufficient interfacial bonding strength, poor tensile formability, and decreased support after high-temperature aging that exist in traditional acoustic packages, providing an efficient, reliable, and durable acoustic solution for electric drive systems of new energy vehicles.

[0022] Compared with the prior art, the present invention has the following significant advantages: 1. The acoustic package for the electric drive system of new energy vehicles of the present invention uses an EPM rubber layer with double-sided PET nonwoven fabric as the sound insulation layer, which significantly enhances the interfacial bonding strength between the EPM rubber layer and the foamed PU layer, effectively preventing the overflow of PU material during the foaming process, and improving the product's qualification rate and reliability. The addition of the second PET nonwoven fabric layer not only improves the scratch resistance of the acoustic package surface, but also maintains good support after high-temperature aging, preventing the overall collapse of the acoustic package and extending the product's service life.

[0023] 2. By covering the EPM rubber layer with PET nonwoven fabric on both sides, the molding and stretching properties of the EPM rubber layer are greatly improved, completely avoiding local damage to the material during the molding process. It can effectively prevent the foamed PU layer from penetrating the EPM rubber layer during high-pressure foaming, thus preventing overflow. The yield rate is increased to over 99.5%.

[0024] 3. The first PET nonwoven fabric layer, as a transition layer between the EPM rubber layer and the foamed PU layer, significantly improves the interfacial bonding strength and increases the peel strength by more than 30%.

[0025] 4. The double-sided PET nonwoven acoustic package still maintains good support after high-temperature aging. The acoustic package does not collapse or delaminate after aging at 120℃ for 720 h.

[0026] 5. By optimizing the composition ratio of the EPM rubber layer and carefully selecting various polymer materials and inorganic fillers, the physical and mechanical properties and processing performance of the EPM rubber layer are improved. This makes the acoustic package easier to operate and control during the preparation process, reducing production costs. Precise control of process parameters, such as the conditions of key steps like mixing, hot pressing, molding, and high-pressure foaming, ensures a tight bond between the layers of the acoustic package and the uniformity of overall performance, thereby improving the acoustic performance and stability of the product. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of the acoustic package for the electric drive system of new energy vehicles described in this invention.

[0028] Figure 2 for Figure 1 The diagram shows an enlarged view of the structure at point W of the acoustic package used in the electric drive system of a new energy vehicle.

[0029] Among them, 1-second PET nonwoven fabric layer, 2-EPM rubber layer, 3-first PET nonwoven fabric layer, 4-foamed PU layer. Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings. The drawings are for illustrative purposes only, representing schematic diagrams rather than actual physical objects, and should not be construed as limiting the scope of this patent. To better illustrate the embodiments of the present invention, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0031] like Figure 1 and Figure 2As shown, the acoustic package for the electric drive system of new energy vehicles of the present invention includes a sound-absorbing layer and a composite sound-insulating layer. The composite sound-insulating layer is an EPM rubber layer 2 with PET nonwoven fabric on both sides, and the sound-absorbing layer is a foamed PU layer 4. The double-sided PET nonwoven fabric includes a first PET nonwoven fabric layer 3 and a second PET nonwoven fabric layer 1. The first PET nonwoven fabric layer 3 covers the EPM rubber layer 2 and is in contact with the foamed PU layer 4, which is used to improve the bonding strength between the EPM rubber layer 2 and the foamed PU layer 4. The second PET nonwoven fabric layer 1 covers the outer surface of the EPM rubber layer 2, which is used to improve the surface scratch resistance and enhance the support of the acoustic package after high-temperature aging.

[0032] The EPM rubber layer, by weight, consists of the following components: POE: 20-50 parts, LLDPE: 5-10 parts, thermoplastic rubber: 5-10 parts, magnesium hydroxide: 15-30 parts, aluminum hydroxide: 15-30 parts, barium sulfate: 15-30 parts, calcium carbonate: 15-30 parts, rubber oil: 3-8 parts, carbon black: 1-5 parts, stearic acid: 1-5 parts, and antioxidant: 1-5 parts. POE, as an elastomer component, enhances the elasticity and low-temperature resistance of rubber products, while the high flowability of LLDPE helps improve the plasticity of rubber processing. The combination of these two components maintains the elastic properties of rubber while improving processing efficiency; furthermore, the addition of thermoplastic rubber provides excellent oil resistance, weather resistance, and electrical insulation, ensuring stable performance even in harsh environments.

[0033] Magnesium hydroxide and aluminum hydroxide, as inorganic flame retardants, not only improve the flame retardant properties of rubber but also absorb heat during combustion, slowing the spread of fire. They also have good compatibility with the rubber matrix and do not significantly affect the physical and mechanical properties of the rubber. Barium sulfate and calcium carbonate, as fillers, increase the volume of rubber, reduce costs, and improve its processing performance and hardness to some extent. Rubber oil, as a plasticizer, reduces intermolecular forces, improves the flexibility and processability of rubber, making it easier to handle during mixing and molding. Carbon black, as a reinforcing agent, significantly improves the tensile strength, tear strength, and abrasion resistance of rubber, making it an indispensable component in rubber products. Stearic acid, as a lubricant, reduces friction between rubber molecules and equipment, improving processing efficiency and also improving the release properties of rubber to some extent. Antioxidants prevent performance degradation caused by oxidation during processing and use, extending the service life of rubber products. During the preparation process, the pressure and time of the internal mixer are precisely controlled to ensure that all raw materials are fully mixed and achieve the optimal composition ratio, laying a good foundation for subsequent hot pressing, molding and high-pressure foaming steps.

[0034] The method for preparing the acoustic package of the present invention includes the following steps: S1. EPM rubber internal mixing: In the internal mixer, add POE, LLDPE, thermoplastic rubber, magnesium hydroxide, aluminum hydroxide, barium sulfate, calcium carbonate, rubber oil, carbon black, stearic acid, and antioxidants (such as amine antioxidants, phenolic antioxidants, thioester antioxidants, and phosphite antioxidants) in sequence according to the formula ratio, and start the internal mixer; S2. While extruding the EPM rubber layer, hot-press the first PET nonwoven fabric layer and the second PET nonwoven fabric layer onto both sides to form a PET / EPM / PET three-layer composite layer. S3. Place the PET / EPM / PET three-layer composite material in the molding die, with the first PET nonwoven fabric layer facing the bottom of the die; S4. Place the molded PET / EPM / PET three-layer composite material into a foaming mold, with the first PET non-woven fabric layer facing the bottom of the mold, inject PU foaming material, and perform high-pressure foaming to firmly bond the foamed PU layer with the first PET non-woven fabric layer, forming a PET / EPM / PET / PU four-layer composite acoustic package. S5. Water jet cutting and assembly to obtain an EPM / PU acoustic package with double-sided PET nonwoven fabric covering of the desired shape.

[0035] During the hot-pressing lamination process, controlling the appropriate temperature and pressure ensures that the first and second PET nonwoven fabric layers adhere tightly to both sides of the EPM rubber layer, forming a stable PET / EPM / PET three-layer composite layer. This step is crucial for improving the interfacial bonding strength and overall structural stability of the acoustic package. During compression molding, precise control of the heating temperature, heating time, and holding pressure time ensures that the PET / EPM / PET three-layer composite material conforms to the mold shape while maintaining a uniform and defect-free internal structure. In the high-pressure foaming step, controlling the mold temperature, foaming time, and foaming pressure allows the foamed PU raw material to uniformly fill the voids in the PET / EPM / PET three-layer composite material, firmly bonding with the first PET nonwoven fabric layer to form a high-performance PET / EPM / PET / PU four-layer composite acoustic package. Finally, after water jet cutting and assembly, an EPM / PU acoustic package with double-sided PET nonwoven fabric is obtained in the required shape. This acoustic package not only has excellent acoustic performance, but also maintains good support and stability under high temperature aging environment, providing a reliable acoustic solution for the electric drive system of new energy vehicles.

[0036] The specific operation is as follows: Example 1

[0037] The method for preparing the acoustic package for the electric drive system of a new energy vehicle in this embodiment includes the following steps: S1.EPM rubber internal mixing: In an internal mixer, add the elastomer, flame retardant, antioxidant N,N-di-sec-butyl-p-phenylenediamine, and other additives sequentially according to the formulation ratio. Start the internal mixer; the specific proportions are shown in Table 1. The mixing pressure is 5 kg, the mixing time is 25 min, and the mixing is complete when the temperature inside the internal mixer is controlled at 130℃.

[0038] S2. Double-sided PET nonwoven fabric lamination: Simultaneously with the extrusion of the EPM rubber layer 2, a first PET nonwoven fabric layer 3 and a second PET nonwoven fabric layer 1 are laminated to both sides, forming a PET / EPM / PET three-layer composite layer. The lamination temperature between the EPM rubber layer and PET is 150℃, the lamination roller pressure is 0.5MPa, the cooling roller temperature is 15℃, and the production line speed is 3m / min. The EPM layer thickness is 1.5mm, and the areal density is 2000g / m³. 2 The first PET nonwoven fabric layer 3 has a basis weight of 70 g / m², and the second PET nonwoven fabric layer 1 has a basis weight of 90 g / m², with a black surface.

[0039] S3. Compression molding: Place the PET / EPM / PET three-layer composite material in the compression molding mold, with the first 3 layers of PET nonwoven fabric facing the bottom of the mold. The heating temperature for compression molding is 220℃, the heating time is 80s, and the holding time is 100s.

[0040] S4. Foaming Molding: The pre-formed PET / EPM / PET three-layer composite material is placed in a foaming mold, with the first PET nonwoven fabric layer 3 facing the bottom of the mold. PU foaming material is injected, and high-pressure foaming is performed to firmly bond the foamed PU layer 4 to the first PET nonwoven fabric layer 3, forming a PET / EPM / PET / PU four-layer composite acoustic package. The mold temperature for high-pressure foaming is 50℃, the foaming time is 60 seconds, and the foaming pressure is 60 kg. The foamed PU density is 50 kg / m³.

[0041] S5. Waterjet Cutting and Assembly: The foamed product is placed into a waterjet cutting mold, programmed, and then waterjet cut to obtain the desired shape of an EPM / PU acoustic bag with double-sided PET nonwoven fabric covering. The waterjet cutting inlet pressure is 8MPa, the air pressure is 0.3MPa, and the chiller water temperature is 20℃. Example 2

[0042] The method for preparing the acoustic package for the electric drive system of a new energy vehicle in this embodiment includes the following steps: S1. EPM rubber internal mixing: In an internal mixer, add the elastomer, flame retardant, antioxidant (hydroquinone), and other additives sequentially according to the formulation ratio. Start the mixer; the specific proportions are shown in Table 1. Set the pressure to 10 kg and the mixing time to 40 min. The mixing process ends when the temperature inside the mixer is controlled at 180℃.

[0043] S2. Double-sided PET nonwoven fabric lamination: Simultaneously with the extrusion of the EPM rubber layer 2, a first PET nonwoven fabric layer 3 and a second PET nonwoven fabric layer 1 are laminated to both sides, forming a PET / EPM / PET three-layer composite layer. The lamination temperature between the EPM rubber layer and PET is 220℃, the lamination roller pressure is 0.7MPa, the cooling roller temperature is 20℃, and the production line speed is 4m / min. The EPM layer thickness is 1.8mm, and the areal density is 2500g / m³. 2 The first PET nonwoven fabric layer 3 has a basis weight of 75 g / m², and the second PET nonwoven fabric layer 1 has a basis weight of 95 g / m², with a black surface.

[0044] S3. Compression molding: Place the PET / EPM / PET three-layer composite material in the compression molding mold, with the first 3 layers of PET nonwoven fabric facing the bottom of the mold. The heating temperature for compression molding is 240℃, the heating time is 110s, and the holding time is 120s.

[0045] S4. Foaming Molding: The pre-formed PET / EPM / PET three-layer composite material is placed in a foaming mold, with the first PET nonwoven fabric layer 3 facing the bottom of the mold. PU foaming material is injected, and high-pressure foaming is performed to firmly bond the foamed PU layer 4 to the first PET nonwoven fabric layer 3, forming a PET / EPM / PET / PU four-layer composite acoustic package. The mold temperature for high-pressure foaming is 90℃, the foaming time is 90 seconds, and the foaming pressure is 90 kg. The density of the foamed PU is 60 kg / m³.

[0046] S5. Waterjet Cutting and Assembly: The foamed product is placed into a waterjet cutting mold, programmed, and then waterjet cut to obtain the desired shape of an EPM / PU acoustic bag with double-sided PET nonwoven fabric covering. The waterjet cutting inlet pressure is 13MPa, the air pressure is 0.9MPa, and the chiller water temperature is 30℃. Example 3

[0047] The method for preparing the acoustic package for the electric drive system of a new energy vehicle in this embodiment includes the following steps: S1.EPM rubber internal mixing: In an internal mixer, add the elastomer, flame retardant, antioxidant (diso-dodecyl thiopropionate), and other additives sequentially according to the formulation ratio. Start the internal mixer; the specific proportions are shown in Table 1. Set the pressure to 4 kg and the mixing time to 20 min. The mixing process ends when the temperature inside the internal mixer is controlled at 120℃.

[0048] S2. Double-sided PET nonwoven fabric lamination: Simultaneously with the extrusion of the EPM rubber layer 2, a first PET nonwoven fabric layer 3 and a second PET nonwoven fabric layer 1 are laminated to both sides, forming a PET / EPM / PET three-layer composite layer. The lamination temperature between the EPM rubber layer and PET is 140℃, the lamination roller pressure is 0.3MPa, the cooling roller temperature is 8℃, and the production line speed is 6m / min. The EPM layer thickness is 3.0mm, and the areal density is 4000g / m³. 2 The first PET nonwoven fabric layer 3 has a basis weight of 110 g / m², and the second PET nonwoven fabric layer 1 has a basis weight of 90 g / m², with a black surface.

[0049] S3. Compression molding: Place the PET / EPM / PET three-layer composite material in the compression molding mold, with the first 3 layers of PET nonwoven fabric facing the bottom of the mold. The heating temperature for compression molding is 210℃, the heating time is 70s, and the holding time is 80s.

[0050] S4. Foaming Molding: The pre-formed PET / EPM / PET three-layer composite material is placed in a foaming mold, with the first PET nonwoven fabric layer 3 facing the bottom of the mold. PU foaming material is injected, and high-pressure foaming is performed to firmly bond the foamed PU layer 4 to the first PET nonwoven fabric layer 3, forming a PET / EPM / PET / PU four-layer composite acoustic package. The mold temperature for high-pressure foaming is 70℃, the foaming time is 60 seconds, and the foaming pressure is 50 kg. The foamed PU density is 90 kg / m³.

[0051] S5. Waterjet Cutting and Assembly: The foamed product is placed into a waterjet cutting mold, programmed, and then waterjet cut to obtain the desired shape of an EPM / PU acoustic bag with double-sided PET nonwoven fabric covering. The waterjet cutting inlet pressure is 10MPa, the air pressure is 0.2MPa, and the chiller water temperature is 15℃. Example 4

[0052] The preparation method of the acoustic package for the electric drive system of new energy vehicles in this embodiment is the same as that in Example 1, except that it is prepared in a mixer according to the proportion of the formula, which is shown in Table 1.

[0053] Comparative Example 1 This comparative example uses an EPM / PU acoustic package with PET nonwoven fabric on one side (PET nonwoven fabric is only covered on the outer surface of the EPM), and the other parameters are the same as in Example 1.

[0054]

[0055] The acoustic packages prepared in Examples 1-4 and Comparative Example 1 were subjected to performance tests, and the test results are shown in Table 2.

[0056]

[0057] Test results show that the EPM / PU acoustic package with double-sided PET nonwoven fabric of the present invention is significantly better than the comparative example with single-sided PET nonwoven fabric in terms of molding tensile formability, interfacial bonding strength, high-temperature aging support and anti-spill performance.

[0058] The above are merely embodiments of the present invention, and the invention is not limited to the fields covered by this embodiment. Commonly known structures and characteristics in the solutions are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the scope of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. An acoustic package for an electric drive system of a new energy vehicle, characterized in that, It includes a sound-absorbing layer and a composite sound-insulating layer. The composite sound-insulating layer is an EPM rubber layer with PET nonwoven fabric on both sides, and the sound-absorbing layer is a foamed PU layer. The double-sided PET nonwoven fabric includes a first PET nonwoven fabric layer and a second PET nonwoven fabric layer. The first PET nonwoven fabric layer covers the EPM rubber layer and is in contact with the foamed PU layer to improve the bonding strength between the EPM rubber layer and the foamed PU layer. The second PET nonwoven fabric layer covers the outer surface of the EPM rubber layer to improve surface scratch resistance and enhance the support of the acoustic package after high-temperature aging.

2. The acoustic package for a new energy vehicle electric drive system according to claim 1, characterized in that, The EPM rubber layer, by weight, consists of the following components; POE: 20-50 parts, LLDPE: 5-10 parts, thermoplastic rubber: 5-10 parts, magnesium hydroxide: 15-30 parts, aluminum hydroxide: 15-30 parts, barium sulfate: 15-30 parts, calcium carbonate: 15-30 parts, rubber oil: 3-8 parts, carbon black: 1-5 parts, stearic acid: 1-5 parts, antioxidant: 1-5 parts.

3. A method for preparing the acoustic package according to any one of claims 1-2, characterized in that, Includes the following steps: S1.EPM rubber mixing: In the internal mixer, add POE, LLDPE, thermoplastic rubber, magnesium hydroxide, aluminum hydroxide, barium sulfate, calcium carbonate, rubber oil, carbon black, stearic acid, and antioxidant in sequence according to the formula ratio, and start the internal mixer. S2. Double-sided PET nonwoven fabric composite: While extruding the EPM rubber layer, the first PET nonwoven fabric layer and the second PET nonwoven fabric layer are hot-pressed onto both sides to form a PET / EPM / PET three-layer composite layer. S3. Compression molding: Place the PET / EPM / PET three-layer composite material in the compression molding mold, with the first PET non-woven fabric layer facing the bottom of the mold; S4. Foaming: Place the molded PET / EPM / PET three-layer composite material into a foaming mold, with the first PET non-woven fabric layer facing the bottom of the mold. Inject PU foaming material and perform high-pressure foaming to firmly bond the foamed PU layer to the first PET non-woven fabric layer, forming a PET / EPM / PET / PU four-layer composite acoustic package. S5. Waterjet Cutting and Assembly: Place the foamed product into a waterjet cutting mold, program it, and then perform waterjet cutting to obtain an EPM / PU acoustic bag with double-sided PET nonwoven fabric covering the desired shape.

4. The method for preparing the acoustic package according to claim 3, characterized in that, The mixing pressure is 4 kg to 10 kg, the mixing time is 20 min to 40 min, and the mixing ends when the temperature inside the mixer is controlled at 120℃ to 180℃.

5. The method for preparing the acoustic package according to claim 3, characterized in that, In step S2, the temperature of the hot pressing composite is 140℃~220℃, the pressure is 0.3MPa~0.7MPa, the temperature is 8℃~20℃, and the production line speed is 2m / min~6m / min.

6. The method for preparing the acoustic package according to claim 3, characterized in that, The EPM rubber layer has a thickness of 0.5mm to 3.0mm and a surface density of 2000g / m³. 2 ~4000g / m 2 .

7. The method for preparing the acoustic package according to claim 3, characterized in that, The first PET nonwoven fabric layer has a basis weight of 70g / m² to 110g / m², the second PET nonwoven fabric layer has a basis weight of 90g / m² to 130g / m², and the foamed PU has a density of 50g / m² to 90kg / m³.

8. The method for preparing the acoustic package according to claim 3, characterized in that, In step S3, the heating temperature for compression molding is 210℃~240℃, the heating time is 70S~110S, and the holding time is 80S~120S.

9. The method for preparing the acoustic package according to claim 3, characterized in that, The high-pressure foaming mold temperature is 50℃~90℃, the foaming time is 60S~90S, and the foaming pressure is 50Kg~90kg.

10. The method for preparing the acoustic package according to claim 3, characterized in that, In step S5, the water pressure for water cutting is 8MPa~13MPa, the air pressure is 0.2MPa~0.9MPa, and the water temperature of the chiller is 15℃~30℃.

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