Environment-friendly automotive trim sound insulation material and preparation method thereof

Abstract

The invention relates to the field of sound insulation materials, in particular to an environment-friendly automobile interior sound insulation material and a preparation method thereof. An environment-friendly automobile interior sound insulation material comprises a mass layer and a sound absorption layer, the mass layer is made of PET and PP composite non-woven fabric, and the weight of the mass layer is 1500-1700 g / m; the sound absorption layer is made of PET non-woven fabric, and the weight of the sound absorption layer is 400-500 g / m. The mass layer is made of PET and PP composite non-woven fabric, the weight reaches 1500-1700 g / m, and by means of the high surface density and composite structure, transmission of low and medium frequency noise of an engine, a road surface and the like can be effectively blocked; the sound absorption layer is a PET non-woven fabric of 400-500 g / m, the porous structure of the sound absorption layer can absorb medium-high frequency noise, and full-band sound insulation is achieved through combination of the quality layer and the sound absorption layer.

Description

Technical Field

[0001] The present application relates to the field of sound insulation materials, and in particular to an environmentally friendly automobile interior sound insulation material and a preparation method thereof. Background Art

[0002] Car sound insulation is a meticulous treatment based on the vehicle's performance, road conditions, and usage conditions. It improves ride comfort by addressing engine noise, the resonance of tire-road vibrations, and friction caused by gaps or aging in components within the vehicle. Currently, the most effective sound insulation method is to add soundproofing pads to key areas of the car, providing not only soundproofing but also heat and dust insulation.

[0003] The commonly used sound insulation pad material at present is a composite structure of polyethylene terephthalate fiber (PET) and ethylene propylene diene monomer (EPDM) as the heavy layer and PUR foam as the inner layer.

[0004] Regarding the aforementioned related technologies, the applicant argues that PET is a thermoplastic polyester with high chemical stability and good recyclability. EPDM is a vulcanized rubber whose molecular chains form a three-dimensional network structure through cross-linking reactions, making traditional recycling difficult. PUR is divided into soft and hard foams, with soft foams being the majority of those found in sound insulation pads. Its molecular chains contain urethane groups and can be recycled through chemical or physical methods. Furthermore, the PET fibers and EPDM rubber in the composite layer are tightly bonded by adhesives, making separation more difficult and potentially impacting recycling efficiency. The PUR foam is tightly bonded to the EPDM / PET composite layer, potentially causing foam breakage during separation, impacting recycled quality and resulting in poor overall recycling efficiency. Summary of the Invention

[0005] In order to improve the recycling performance of sound insulation materials, the present application provides an environmentally friendly automobile interior sound insulation material and a preparation method thereof.

[0006] In a first aspect, the present application provides an environmentally friendly automobile interior sound insulation material, which adopts the following technical solution.

[0007] An environmentally friendly automobile interior sound insulation material comprises a mass layer and a sound absorption layer. The mass layer is a PET and PP composite nonwoven fabric with a weight of 1500-1700 g / m²; the sound absorption layer is a PET nonwoven fabric with a weight of 400-500 g / m².

[0008] By adopting the above technical solution, the mass layer uses a PET and PP composite non-woven fabric with a weight of 1500-1700g / m². With its high surface density and composite structure, it can effectively block the propagation of medium and low-frequency noise (200-1000Hz) from the engine, road, etc.; the sound-absorbing layer is a PET non-woven fabric with a weight of 400-500g / m². Its porous structure can absorb medium and high-frequency noise (above 1000Hz). The combination of the mass layer and the sound-absorbing layer achieves full-band sound insulation, significantly improving driving comfort.

[0009] Both PET and PP are recyclable polymer materials. After being discarded, automotive interior materials can be easily recycled through physical recycling (such as melt granulation) or chemical recycling (such as depolymerization and regeneration), reducing pollution to the environment. In addition, no adhesives containing harmful substances such as formaldehyde and benzene are used in the production process, which meets the environmental protection standards for automotive interiors, reduces volatile organic compound (VOC) emissions in the car, and ensures the air quality inside the car.

[0010] PET and PP composite nonwovens combine the high strength and high rigidity of PET with the flexibility and fatigue resistance of PP, giving the quality layer excellent tensile strength, tear resistance and impact resistance; the PET nonwoven sound-absorbing layer not only ensures the sound absorption effect, but also has good wear resistance and aging resistance, can adapt to the complex use environment of automobile interiors, and extend the service life of the sound insulation material.

[0011] Furthermore, the mass layer comprises the following raw materials in parts by weight: 150-250 parts of PET chips, 350-400 parts of PP chips, 25-35 parts of gelatin, 25-35 parts of gum arabic, 0.3-0.8 parts of nano-SiO2, 60-80 parts of capric acid, 25-35 parts of lauric acid, and 0.1-0.3 parts of antioxidant.

[0012] Furthermore, the weight ratio of capric acid to lauric acid is (2-2.5):1.

[0013] Furthermore, the weight ratio of capric acid to lauric acid is 2.3:1.

[0014] Furthermore, the preparation method of the quality layer is:

[0015] 1) Preparation of phase change microcapsules

[0016] Gelatin and gum arabic are dissolved to obtain a mixed solution, nano-SiO2 is dispersed in the mixed solution, and then capric acid and lauric acid are added and emulsified to obtain an emulsion;

[0017] Adjust the pH of the emulsion to 4.0 and stir at 150 rpm for 2 hours at 35-45°C to promote the formation of microcapsule primary aggregates;

[0018] Add a cross-linking agent and carry out a cross-linking reaction at 45-55°C for 4 hours. After the reaction is completed, dry the product to obtain phase change microcapsules with a particle size of 10-20 μm.

[0019] 2) Spinning

[0020] PP chips, phase change microcapsules and antioxidants are mixed as the core layer raw material; PET chips are used as the skin layer raw material; the skin layer raw material and core layer raw material are fed into the extruder separately, the melt is squeezed and melted by the screw, and then extruded through the spinneret to form a fiber stream, which is solidified under the action of side blowing cooling, and then drawn by the drawing device, and finally wound into a skin-core fiber;

[0021] 3) Nonwoven fabric forming

[0022] The sheath-core fiber is fed into the feeding system of the nonwoven fabric production equipment, and then goes through laying, hot rolling bonding, and needle punching reinforcement to obtain the quality layer.

[0023] The above technical solution is usually adopted. The quality layer blocks medium and low frequency noise through the high surface density of PET and PP composite non-woven fabric. At the same time, the newly added phase change microcapsule structure can reduce the material temperature when absorbing heat, reduce the thermal expansion and contraction deformation of the material caused by the increase in temperature, avoid the increase of gaps in the sound insulation structure and reduce the sound insulation effect, further ensure the stability of the sound insulation performance in the entire frequency band, and continuously improve driving comfort.

[0024] Phase-change microcapsules made of capric acid and lauric acid in a specific ratio have a melting point of 25-30°C. They can absorb or release heat through solid-liquid phase change when the temperature inside the vehicle fluctuates, reducing the amplitude of temperature fluctuations inside the vehicle, reducing the frequency of air conditioning use, helping to save energy and reduce emissions in the vehicle, and at the same time creating a more comfortable temperature environment for drivers and passengers.

[0025] Building on the existing recyclable advantages of PET and PP, gelatin and gum arabic, as naturally degradable wall materials, work together with nano-SiO2 to further enhance the degradability and recyclability of discarded materials while ensuring the performance of the microcapsules, thereby reducing environmental pollution. Furthermore, no harmful substances are added during the production process, continuously ensuring the quality of air inside the vehicle.

[0026] The reasonable ratio of PET chips and PP chips, combined with nano-SiO2 reinforced microcapsule wall material, gives the quality layer higher tensile strength, tear resistance and impact resistance; the addition of antioxidants effectively inhibits the oxidative degradation of PP during the high-temperature spinning process, extending the service life of the material; the stable structure of the phase change microcapsules can withstand the vibration and impact of the car during driving, reduce internal damage to the material, and make it better adapt to the complex environment of the car interior.

[0027] Furthermore, the spinning process parameters are:

[0028] Screw temperature: The temperature of each section of the skin screw is set to 260℃, 270℃, and 280℃ in sequence; the temperature of each section of the core screw is set to 180℃, 190℃, and 210℃ in sequence;

[0029] Spinning assembly: Use a skin-core spinneret with 150 spinneret holes and a skin-core diameter ratio of 3:1;

[0030] Spinning speed: controlled at 2800-3200m / min;

[0031] Drafting conditions: Draft ratio is set to 3.5-4.0 times, and the drafting temperature is 90-100℃;

[0032] Cooling conditions: side wind speed 0.8m / s, wind temperature 25℃, relative humidity 65%.

[0033] Furthermore, the thickness of the mass layer is 5-10 mm, and the thickness of the sound absorption layer is 20-30 mm.

[0034] By adopting the above technical solution, the quality layer with a thickness of 5-10mm and a high surface density of 1500-1700g / m² effectively enhances the barrier ability against medium and low frequency noise (200-1000Hz); the sound absorption layer with a thickness of 20-30mm and a PET non-woven fabric of 400-500g / m² expands the sound absorption area of ​​the porous structure and improves the absorption efficiency of medium and high frequency noise (above 1000Hz), achieving maximum sound insulation performance across the entire frequency band and significantly reducing the noise level inside the vehicle.

[0035] The thickness of the mass layer and the sound-absorbing layer is precisely proportioned according to the requirements of mechanical and acoustic performance, which not only ensures the strength of the mass layer in blocking noise, but also ensures that the sound-absorbing layer has sufficient sound-absorbing space. At the same time, the layered structure can disperse external stress, reduce the risk of material damage caused by vibration, extrusion, etc., and extend the overall service life.

[0036] The thickness of the mass layer makes the heat exchange area and path between the internal phase change microcapsules and the external environment more reasonable. The phase change material composed of capric acid and lauric acid can absorb or release heat more quickly and efficiently within the phase change range of 25-30°C, further reducing the temperature fluctuation range in the car and shortening the use time of air conditioning. While achieving energy conservation and emission reduction, it provides a more constant and comfortable temperature for drivers and passengers.

[0037] Furthermore, the surface of the mass layer is provided with a plurality of continuous isolated surface units divided into a plurality of isolated surface units interconnected by grooves.

[0038] Furthermore, the isolated surface unit has a regular polygonal shape.

[0039] By adopting the above-mentioned technical solution, the design of regular polygonal isolated surface units and grooves on the surface of the mass layer forms a structure similar to an acoustic diffuser, which can reflect and scatter the incident sound waves multiple times, avoid the concentrated reflection of sound waves to produce standing waves, further reduce the echo and resonance in the car, improve the sound quality, and make the driving environment quieter.

[0040] Continuously divided, isolated surface units are connected by grooves, forming a honeycomb-like mechanical structure without reducing the overall strength of the material. This enhances the mass layer's resistance to deformation. During vehicle operation, it effectively resists vibration and impact, preventing surface cracking or denting, and maintaining long-term stability in sound insulation performance.

[0041] In a second aspect, the present application provides a method for preparing an environmentally friendly automobile interior sound insulation material, which adopts the following technical solution.

[0042] A method for preparing an environmentally friendly automobile interior sound insulation material comprises the following steps:

[0043] S1. The mass layer and the sound absorbing layer are respectively hot-pressed in a mold;

[0044] S2. Bonding the formed mass layer to the sound-absorbing layer to obtain an environmentally friendly automobile interior sound insulation material.

[0045] In summary, this application has the following beneficial effects:

[0046] The mass layer in this application utilizes a PET and PP composite nonwoven fabric weighing 1500-1700g / m². Its high surface density and composite structure effectively block the transmission of low- and medium-frequency noise from the engine and road, among other sources. The sound-absorbing layer, a 400-500g / m² PET nonwoven fabric, has a porous structure that absorbs medium- and high-frequency noise. The combination of the mass layer and the sound-absorbing layer provides full-band sound insulation, significantly enhancing driving comfort. Both PET and PP are recyclable polymers, making them easily recyclable after discarding automotive interior materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is a schematic diagram of the overall structure of Example 1 of this application.

[0048] In the figure: 1, mass layer; 11, groove; 12, surface unit; 2, sound absorption layer. DETAILED DESCRIPTION

[0049] The present application is further described in detail below with reference to the embodiments.

[0050] Preparation examples of raw materials and intermediates

[0051] raw material

[0052] The raw materials in the examples of this application can be obtained commercially;

[0053] PET chips, intrinsic viscosity 0.85dL / g, melting point 255℃;

[0054] PP chips, melt flow rate 25g / 10min;

[0055] Gelatin, food grade;

[0056] Gum Arabic, food grade;

[0057] Nano-SiO2, particle size 50-80nm;

[0058] Antioxidant, antioxidant 1010;

[0059] Cross-linking agent, 37% formaldehyde solution.

[0060] Preparation Example

[0061] Preparation Examples 1-5

[0062] A quality layer 1, prepared by:

[0063] 1) Preparation of phase change microcapsules

[0064] According to the raw material ratio in Table 1, gelatin and gum arabic were added to deionized water, and then nano-SiO2 was added. The mixture was stirred at 200 rpm at 60°C for 1 hour until the solution was clear to obtain a mixed solution. Capric acid and lauric acid were then added and emulsified to obtain an emulsion.

[0065] 5% acetic acid solution was added to adjust the pH of the emulsion to 4.0, and the mixture was stirred at 150 rpm for 2 h at 40 °C to promote the formation of microcapsule primary aggregates;

[0066] Add a cross-linking agent and carry out cross-linking reaction at 50°C for 4 hours. After the reaction, dry the product in a spray dryer with the air inlet temperature set at 180°C and the air outlet temperature set at 80°C to obtain phase change microcapsules with a particle size of 10-20μm.

[0067] 2) Spinning

[0068] PP chips, phase change microcapsules and antioxidants are mixed as the core layer raw material; PET chips are used as the skin layer raw material; the skin layer raw material and core layer raw material are fed into the extruder separately, the melt is squeezed and melted by the screw, and then extruded through the spinneret to form a fiber stream, which is solidified under the action of side blowing cooling, and then drawn by the drawing device, and finally wound into a skin-core fiber;

[0069] The spinning process parameters are:

[0070] Screw temperature: The temperature of each section of the skin screw is set to 260℃, 270℃, and 280℃ in sequence; the temperature of each section of the core screw is set to 180℃, 190℃, and 210℃ in sequence;

[0071] Spinning assembly: Use a skin-core spinneret with 150 spinneret holes and a skin-core diameter ratio of 3:1;

[0072] Spinning speed: controlled at 3000m / min;

[0073] Drafting conditions: Draft ratio is set to 4.0 times, and drafting temperature is 95°C;

[0074] Cooling conditions: side wind speed 0.8m / s, wind temperature 25℃, relative humidity 65%;

[0075] 3) Nonwoven fabric forming

[0076] The core-sheath fiber is fed into the feeding system of the nonwoven production equipment, and then through laying, hot-calendering bonding, and needle punching reinforcement, quality layer 1 is obtained:

[0077] Laying: Using air-laid technology, the web speed is controlled at 10m / min, forming a fiber web with a grammage of 1600g / m².

[0078] Hot rolling bonding: The fiber web is fed into a hot rolling mill with the hot rolling temperature set at 175°C and the pressure set at 1.5 MPa to bond the fibers to each other.

[0079] Needling reinforcement: Using a triaxial needling machine with a needle density of 230 needles / cm², the hot-calendered web is needled to enhance the strength and structural stability of the nonwoven fabric in the thickness direction;

[0080] The resulting mass layer 1 has a weight of 1600 g / m².

[0081] Table 1 Raw material ratios for preparation examples 1-5 (kg)

[0082]

[0083] Preparation Example 6

[0084] A quality layer 1, prepared by:

[0085] 1) Spinning

[0086] PP chips and antioxidants are mixed as the core layer raw material; PET chips are used as the skin layer raw material; the skin layer raw material and the core layer raw material are fed into the extruder separately, the melt is squeezed and melted by the screw, and then extruded through the spinneret to form a fiber stream, which is solidified under the action of side blowing cooling, and then drawn by the drawing device, and finally wound into a skin-core fiber;

[0087] The spinning process parameters are:

[0088] Screw temperature: The temperature of each section of the skin screw is set to 260℃, 270℃, and 280℃ in sequence; the temperature of each section of the core screw is set to 180℃, 190℃, and 210℃ in sequence;

[0089] Spinning assembly: Use a skin-core spinneret with 150 spinneret holes and a skin-core diameter ratio of 3:1;

[0090] Spinning speed: controlled at 3000m / min;

[0091] Drafting conditions: Draft ratio is set to 4.0 times, and drafting temperature is 95°C;

[0092] Cooling conditions: side wind speed 0.8m / s, wind temperature 25℃, relative humidity 65%;

[0093] 3) Nonwoven fabric forming

[0094] The core-sheath fiber is fed into the feeding system of the nonwoven production equipment, and then through laying, hot-calendering bonding, and needle punching reinforcement, quality layer 1 is obtained:

[0095] Laying: Using air-laid technology, the web speed is controlled at 10m / min, forming a fiber web with a grammage of 1600g / m².

[0096] Hot rolling bonding: The fiber web is fed into a hot rolling mill with the hot rolling temperature set at 175°C and the pressure set at 1.5 MPa to bond the fibers to each other.

[0097] Needling reinforcement: Using a triaxial needling machine with a needle density of 230 needles / cm², the hot-calendered web is needled to enhance the strength and structural stability of the nonwoven fabric in the thickness direction;

[0098] The resulting mass layer 1 has a weight of 1600 g / m².

[0099] Example

[0100] Example 1

[0101] An environmentally friendly automobile interior sound insulation material, and a preparation method thereof is as follows:

[0102] S1. The quality layer 1 and the sound absorbing layer 2 obtained in Preparation Example 1 were respectively hot-pressed in a mold; the sound absorbing layer 2 was a PET nonwoven fabric weighing 450 g / m²;

[0103] The surface of the mold quality layer 1 of the quality layer 1 is provided with a plurality of continuous isolated surface units 12 which are interconnected by grooves 11. The isolated surface units 12 have a regular polygonal shape, which is a hexagon in this embodiment. The local material thickness of the quality layer 1 at the grooves 11 is substantially equal to the local material thickness in the isolated surface units 12. The thickness difference does not exceed 0.5 mm.

[0104] The thickness of the mass layer 1 is 8 mm, and the thickness of the sound absorbing layer 2 is 25 mm;

[0105] S2. The formed quality layer 1 and the sound absorbing layer 2 are bonded together using a PET melt film to obtain an environmentally friendly automobile interior sound insulation material.

[0106] Examples 2-6

[0107] Different from Example 1, the quality layers 1 in Examples 2-6 are respectively from Preparation Examples 2-6.

[0108] Example 7

[0109] Different from Example 2, in Example 7, the weight of the mass layer 1 is 1500 g / m², and the weight of the sound absorbing layer 2 is 500 g / m².

[0110] Example 8

[0111] The difference from Example 2 is that in Example 8, the weight of the mass layer 1 is 1700 g / m², and the weight of the sound absorbing layer 2 is 400 g / m².

[0112] Comparative Example

[0113] Comparative Example 1

[0114] Different from Example 1, in Comparative Example 1, the mass layer 1 is a composite nonwoven fabric of PET and EPDM, and the sound absorbing layer 2 is PUR foam.

[0115] Comparative Example 2

[0116] Different from Example 1, the mass layer 1 in Comparative Example 2 is a PET nonwoven fabric. The difference from Example 1 is that when preparing the mass layer 1, only PET is used for spinning.

[0117] Performance testing

[0118] The following performance tests were performed on the sound insulation materials obtained in the examples and comparative examples. The test results are shown in Table 2.

[0119] Thermal resistance test: The thermal resistance R value is tested in accordance with GB / T 12801-2018 "Thermal resistance measurement method and thermal resistance accuracy assessment".

[0120] Sound insulation performance test: The sound transmission loss of the sound insulation material is tested in accordance with GB / T 18696-2019 "Measurement of sound absorption coefficient and acoustic impedance in acoustic impedance tubes".

[0121] Table 2 Performance test results

[0122]

[0123] Combining Examples 1-8 with Comparative Examples 1-2 and Table 2, it can be seen that the sound transmission loss of the sound insulation materials obtained in Examples 1-8 is greater than that of Comparative Examples 1-2, or is not much different from that of Comparative Example 1. This indicates that the sound insulation performance of the sound insulation materials obtained in this application is comparable to or better than that of Comparative Example 1. However, the thermal resistance R values ​​of the sound insulation materials obtained in Examples 1-8, except for Example 6, are greater than that of Comparative Example 1, indicating that the sound insulation materials obtained in this application have excellent thermal and sound insulation performance. In addition, both PP and PET in the sound insulation materials of this application are excellent recyclable materials, and the overall recycling performance is better.

[0124] Combining Examples 1-8 with Table 2, it can be seen that the thermal and sound insulation properties of the materials obtained in Examples 1-5 and Examples 7-8 are superior to those of Comparative Example 1. This is likely due to the incorporation of the phase-change microcapsule structure, which lowers the material temperature when absorbing heat, reducing thermal expansion and contraction caused by temperature rise. This prevents the increase in gaps in the sound insulation structure, which would otherwise reduce the sound insulation effect, and further ensures the stability of sound insulation performance across the entire frequency range. Furthermore, the phase-change microcapsules, made from capric acid and lauric acid in a specific ratio, have a melting point of 25-30°C. These phase-change microcapsules absorb or release heat through a solid-liquid phase transition when the vehicle's interior temperature fluctuates, reducing the magnitude of temperature fluctuations and the frequency of air conditioning use, thereby contributing to energy conservation and emission reduction in the vehicle, while also creating a more comfortable temperature environment for the driver and passengers.

[0125] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. An environmentally friendly automobile interior sound insulation material, comprising a mass layer (1) and a sound absorbing layer (2), characterized in that: The mass layer (1) is a PET and PP composite non-woven fabric with a weight of 1500-1700 g / m²; the sound absorption layer (2) is a PET non-woven fabric with a weight of 400-500 g / m².

2. The environmentally friendly automobile interior sound insulation material according to claim 1, characterized in that: The mass layer (1) comprises the following raw materials in parts by weight: 150-250 parts of PET chips, 350-400 parts of PP chips, 25-35 parts of gelatin, 25-35 parts of gum arabic, 0.3-0.8 parts of nano-SiO2, 60-80 parts of capric acid, 25-35 parts of lauric acid, and 0.1-0.3 parts of antioxidant.

3. The environmentally friendly automobile interior sound insulation material according to claim 2, characterized in that: The weight ratio of capric acid to lauric acid is (2-2.5):

1.

4. The environmentally friendly automobile interior sound insulation material according to claim 2, characterized in that: The weight ratio of capric acid to lauric acid is 2.3:

1.

5. The environmentally friendly automobile interior sound insulation material according to claim 2, characterized in that: The preparation method of the quality layer (1) is: 1) Preparation of phase change microcapsules Gelatin and gum arabic are dissolved to obtain a mixed solution, nano-SiO2 is dispersed in the mixed solution, and then capric acid and lauric acid are added and emulsified to obtain an emulsion; Adjust the pH of the emulsion to 4.0 and stir at 150 rpm for 2 hours at 35-45°C to promote the formation of microcapsule primary aggregates; Add a cross-linking agent and carry out a cross-linking reaction at 45-55°C for 4 hours. After the reaction is completed, dry the product to obtain phase change microcapsules with a particle size of 10-20 μm. 2) Spinning PP chips, phase change microcapsules and antioxidants are mixed as the core layer raw material; PET chips are used as the skin layer raw material; the skin layer raw material and core layer raw material are fed into the extruder separately, the melt is squeezed and melted by the screw, and then extruded through the spinneret to form a fiber stream, which is solidified under the action of side blowing cooling, and then drawn by the drawing device, and finally wound into a skin-core fiber; 3) Nonwoven fabric forming The core-sheath fiber is fed into the feeding system of the nonwoven fabric production equipment, and then is laid, hot-rolled and bonded, and needle-punched to obtain a quality layer (1).

6. The environmentally friendly automobile interior sound insulation material according to claim 5, characterized in that: The process parameters of the spinning are: Screw temperature: The temperature of each section of the skin screw is set to 260℃, 270℃, and 280℃ in sequence; the temperature of each section of the core screw is set to 180℃, 190℃, and 210℃ in sequence; Spinning assembly: Use a skin-core spinneret with 150 spinneret holes and a skin-core diameter ratio of 3:1; Spinning speed: controlled at 2800-3200m / min; Drafting conditions: Draft ratio is set to 3.5-4.0 times, and the drafting temperature is 90-100℃; Cooling conditions: side wind speed 0.8m / s, wind temperature 25℃, relative humidity 65%.

7. The environmentally friendly automobile interior sound insulation material according to claim 1, characterized in that: The thickness of the mass layer (1) is 5-10 mm, and the thickness of the sound absorbing layer (2) is 20-30 mm.

8. The environmentally friendly automobile interior sound insulation material according to claim 1, characterized in that: The surface of the mass layer (1) is provided with a plurality of continuous isolated surface units (12) divided into a plurality of isolated surface units (12) interconnected by grooves (11).

9. The environmentally friendly automobile interior sound insulation material according to claim 8, characterized in that: The isolated surface elements (12) have a regular polygonal shape.

10. A method for preparing the environmentally friendly automobile interior sound insulation material according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. The mass layer (1) and the sound absorbing layer (2) are respectively hot-pressed in a mold; S2. Bonding the formed mass layer (1) to the sound absorbing layer (2) to obtain an environmentally friendly automobile interior sound insulation material.

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