Sound absorbing and insulating material

Abstract

The application discloses a sound-absorbing and sound-insulating material and relates to the technical field of sound-absorbing and sound-insulating materials. The sound-absorbing and sound-insulating material is characterized in that PET hollow fibers are used as a framework, PP melt-blown fibers are used as filling materials to form a high-frequency sound-absorbing layer, the PET hollow fibers are used as a framework structure to ensure that the sound-absorbing and sound-insulating material has sufficient strength and stability, and melt-blown cloth fluff is added to the high-frequency sound-absorbing layer to prepare a low-frequency sound-absorbing layer. The PP melt-blown fibers are directly deposited and embedded into the PET fiber framework to form a material with small pores but many pores. The high-frequency sound-absorbing layer and the low-frequency sound-absorbing layer are layered and stacked, and non-woven fabric is arranged on the outer surface to form a novel sound-absorbing and sound-insulating material. The sound-absorbing and sound-insulating material not only has better sound-absorbing performance, but also has improved low-frequency sound-absorbing performance.

Description

Technical Field

[0001] This invention relates to the field of sound-absorbing and sound-insulating materials technology, specifically to a sound-absorbing and sound-insulating material. Background Technology

[0002] Automotive sound insulation cotton is a porous fiber material made primarily of polyester fiber, glass fiber, or PP meltblown fiber through a special process. Its interior is filled with interconnected tiny pores. When sound waves from the engine, tires, and wind enter, they are repeatedly reflected and rubbed between the fibers, converting sound energy into minute amounts of heat energy, which gradually attenuates the sound. This effectively reduces interior noise and weakens echoes and resonance. At the same time, this structure also gives the material good thermal insulation, waterproofing, moisture resistance, and a certain degree of flame retardancy, making it widely used in modern automobiles.

[0003] Porous fiber sound insulation cotton relies on its interconnected micropores to convert sound energy into heat energy due to viscous resistance and fiber friction after sound waves enter. However, this mechanism dictates that its sound absorption coefficient increases with frequency, and its absorption capacity for low-frequency sound waves is inherently weak. Studies have shown that this type of material has significantly insufficient sound absorption in the low-frequency range below 1250 Hz, making it difficult to effectively handle low-frequency noise generated by engines, tires, etc. In the critical 400-1000 Hz noise frequency range, the average sound absorption coefficient of some traditional materials is usually below 0.3. Therefore, developing a "super sound-absorbing cotton" with an ultra-high sound absorption coefficient (average close to 0.4) and environmental friendliness can precisely fill the current market's urgent need for "innovation in basic materials." Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a sound-absorbing and sound-insulating material with significantly improved sound insulation and sound absorption effects.

[0005] The present invention proposes a technical solution to solve the above-mentioned technical problems: a sound-absorbing and sound-insulating material, which is made by layering at least one high-frequency sound-absorbing layer and at least one low-frequency sound-absorbing layer; the high-frequency sound-absorbing layer is made by using PET hollow fiber as a skeleton and PP meltblown fiber as the filling material in the skeleton; the low-frequency sound-absorbing layer is made by using PET hollow fiber as a skeleton, using PP meltblown fiber as the filling material in the skeleton, and adding meltblown fabric fibers into the pores.

[0006] Preferably, the meltblown fabric pile is made of PP through meltblowing with a basis weight of 30-150 g / m². 2 The meltblown fabric is then directly crushed or rolled into meltblown fabric fibers with a particle size of 0.5 to 2 mm, preferably 1 to 2 mm.

[0007] Preferably, the PET hollow fiber skeleton of the high-frequency sound-absorbing layer and the low-frequency sound-absorbing layer has a fineness of 1.5 to 6 dtex; Preferably, the mass ratio of PP to PET in the high-frequency sound-absorbing layer is 2 to 4:1, and the mass ratio of PP, PET, and meltblown fabric fibers in the low-frequency sound-absorbing layer is 2 to 4:1:0.2 to 0.4.

[0008] Preferably, the basis weight of the high-frequency sound-absorbing layer is 50–300 g / m². 2 The preferred concentration is 150–250 g / m³. 2， The weight of the low-frequency sound-absorbing layer is 150–600 g / m². 2 Preferably, it is 350–550 g / m³ 2 .

[0009] Preferably, the outer surface of the high-frequency sound-absorbing layer and the low-frequency sound-absorbing layer after being layered and stacked is provided with non-woven fabric.

[0010] Preferably, the method for preparing the sound-absorbing and sound-insulating material includes the following specific steps: S1. PET is melted and conveyed to the spinning box, and extruded from the shaped spinneret. It is then cooled and shaped, stretched and curled, and then shaped at 100-150℃ to obtain a PET hollow fiber skeleton. S2. PP is placed in a meltblown machine, melted and plasticized by a screw extruder and filtered. After filtration, it is sent to the meltblown die by a metering pump, melt-extruded, stretched at 200-280℃, and PP meltblown fibers are formed on the receiving curtain. Below the meltblown die, a PET hollow fiber skeleton is introduced. The PP meltblown fibers and meltblown fabric fluff are directly deposited and embedded in the PET fiber skeleton. After pressing, a low-frequency sound-absorbing layer is obtained. S3. PP is placed in a meltblown machine, melted and plasticized by a screw extruder and filtered. After filtration, it is sent to the meltblown die by a metering pump, melted and extruded, stretched at 200-280℃, and PP meltblown fibers are formed on the receiving curtain. Below the meltblown die, a PET hollow fiber skeleton is introduced, and the PP meltblown fibers are directly deposited and embedded in the PET fiber skeleton. After pressing, a high-frequency sound-absorbing layer is obtained. S4. High-frequency sound-absorbing layer and low-frequency sound-absorbing layer are stacked in layers to obtain sound-absorbing and sound-insulating material.

[0011] Preferably, in steps S2 and S3 above, the melt index of PP is 500 to 2000 g / 10 min.

[0012] Preferably, the method for preparing the meltblown fabric fleece is as follows: PP is placed in a single-screw extruder with a barrel temperature of 180-250℃, a die temperature of 220-260℃, a hot air temperature of 200-280℃, a receiving distance of 10-50cm, and a speed of 10-30m / min. It is then hot-pressed at 120-140℃ and 0.2-0.4MPa for 1-20s, followed by crushing or rolling and then crushing to obtain the meltblown fabric fleece.

[0013] Preferably, the reduction rate after rolling is 50%–100%. This reduction rate is controlled by the amount of rolling reduction. A low reduction rate (80%–100%) results in slight deformation, large porosity, and low meltblown fabric pile density; a high reduction rate (50%–70%) results in greater deformation and higher meltblown fabric pile density.

[0014] Compared with the prior art, the beneficial effects achieved by the present invention are: The sound-absorbing and sound-insulating material of this invention uses PET hollow fiber as a skeleton and PP meltblown fiber as a filler to form a high-frequency sound-absorbing layer. Using PET hollow fiber as the skeleton structure ensures sufficient strength and stability. PP meltblown fiber is directly deposited and embedded into the PET fiber skeleton, forming a material with small but numerous pores, resulting in excellent sound absorption and insulation performance. A low-frequency sound-absorbing layer is then formed by adding meltblown fabric fluff to the high-frequency sound-absorbing layer. The meltblown fabric fluff is made from PP meltblown material, which is then directly pulverized or rolled into meltblown fabric fluff smaller than 2mm, and uniformly added to the high-frequency sound-absorbing layer to form the low-frequency sound-absorbing layer. The two sound-absorbing and sound-insulating materials are then layered and stacked, with a non-woven fabric on the surface, forming a novel sound-absorbing and sound-insulating material that not only achieves better sound insulation performance but also improves low-frequency sound absorption performance.

[0015] Applying sound-absorbing cotton materials to sound sources or reflective surfaces (such as the inner walls of speaker enclosures, car doors, and walls) effectively absorbs sound waves and reduces resonance. It aims to significantly improve acoustic performance (noise, vibration, and acoustic roughness) through breakthrough acoustic technology and lightweight design. Applied to car doors, roofs, trunks, etc., it absorbs engine, road, and wind noise, improving driving comfort. In open-plan office environments, it reduces background noise, creating a quieter workspace. In large public spaces, it is often used on ceilings or walls to absorb crowd noise and equipment noise, improving the overall acoustic environment. It can also improve indoor acoustics, reducing mutual interference from conversations and enhancing focus and privacy. Attached Figure Description

[0016] Figure 1 The diagram shows the sound absorption coefficients of the high-frequency and low-frequency sound-absorbing layers in Example 1 at frequencies ranging from 50 to 6300 Hz.

[0017] Figure 2 The diagram shows the sound absorption coefficients of the sound-absorbing and sound-insulating materials prepared in Example 1 and Comparative Example 1 at frequencies ranging from 50 to 6300 Hz.

[0018] Figure 3 The diagram shows the sound absorption coefficients of the low-frequency sound-absorbing layers prepared in Example 1 and Comparative Example 1 at frequencies ranging from 50 to 6300 Hz.

[0019] Figure 4The diagram shows the sound absorption coefficients of the high-frequency sound-absorbing layers prepared in Example 1 and Comparative Example 1 at frequencies ranging from 50 to 6300 Hz.

[0020] Figure 5 This is a comparison chart of the sound insulation performance of the sound-absorbing and sound-insulating materials prepared in Example 1 and Comparative Example 1. Detailed Implementation

[0021] The present invention will be specifically described below through embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above description. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those skilled in the art.

[0022] The sound-absorbing and sound-insulating material prepared in this invention uses PP nonwoven fabric purchased from Ruiguang Nonwoven Fabric Group Co., Ltd.

[0023] To more clearly illustrate the method provided by the present invention, the following embodiments are provided for detailed explanation. The test methods for various indicators of the sound-absorbing and sound-insulating materials prepared in the embodiments and comparative examples are as follows: Sound absorption performance: The sound absorption coefficient of the sound-absorbing and sound-insulating materials prepared in the examples and comparative examples was determined in accordance with GB / T 33620.

[0024] Sound insulation performance: The sound-absorbing and sound-insulating materials prepared in the examples and comparative examples were subjected to insertion loss tests in accordance with the method specified in the standard Q / MAT 5521 of China Automotive Engineering Research Institute (Tianjin) Co., Ltd.

[0025] Example 1 The method for preparing the sound-absorbing and sound-insulating material in this embodiment is as follows: S1. PET is melted and conveyed to the spinning box, and extruded from the shaped spinneret. It is cooled and shaped at 20°C, stretched and crimped at 100°C with a stretch ratio of 3 times, and then heat-set at 120°C to obtain a PET hollow fiber skeleton with a fineness of 3dtex. S2. Place the PP in a single-screw extruder with a barrel temperature of 220℃, a die temperature of 240℃, a hot air temperature of 220℃, an air pressure of 0.1MPa, a receiving distance of 10cm, and a speed of 10m / min. Then, hot-press at 120℃ and 0.2MPa for 10s to produce a product with a basis weight of 80g / m³. 2The meltblown fabric is first processed and then directly pulverized to obtain meltblown fabric fluff with a particle size controlled at around 1mm. PP is placed in a meltblown machine, melted and plasticized by a screw extruder, and then filtered. After filtration, it is pumped to the meltblown die head for melt extrusion and stretching at 250℃ to form PP meltblown fibers on a receiving curtain. Below the meltblown die head, a PET hollow fiber skeleton is introduced, and the PP meltblown fibers and meltblown fabric fluff are directly deposited and embedded into the PET fiber skeleton. After residual heat pressing, a low-frequency sound-absorbing layer with a basis weight of 490g / m² is obtained. 2 The thickness is 8mm, the mass ratio of PP, PET hollow fiber skeleton and meltblown fabric pile is 2:1:0.2, and the melt index of PP is 500g / 10min; S3. PP is placed in a meltblown machine, melted and plasticized by a screw extruder, and then filtered. After filtration, it is pumped to the meltblown die by a metering pump for melt extrusion. The PP is stretched at 200°C to form PP meltblown fibers on a receiving curtain. Below the meltblown die, a PET hollow fiber skeleton is introduced, and the PP meltblown fibers are directly deposited and embedded into the PET fiber skeleton. After residual heat pressing, a high-frequency sound-absorbing layer is obtained with a basis weight of 200 g / m². 2 The thickness is 8mm; the mass ratio of PP to PET is 2:1. S4. A low-frequency sound-absorbing layer and a high-frequency sound-absorbing layer are stacked together, and the outer surfaces of both are covered with non-woven fabric to obtain a sound-absorbing and sound-insulating material.

[0026] Example 2 The method for preparing the sound-absorbing and sound-insulating material in this embodiment is as follows: S1. PET is melted and fed into a spinning box, and extruded from a shaped spinneret. It is then cooled and shaped at 25°C, stretched and crimped at 80°C with a stretch ratio of 2.9 times, and heat-set at 110°C to obtain a PET hollow fiber skeleton with a fineness of 4.5 dtex. S2. Place the PP in a single-screw extruder with a barrel temperature of 220℃, a die temperature of 240℃, a hot air temperature of 220℃, an air pressure of 0.1MPa, a receiving distance of 10cm, and a speed of 10m / min. Then, hot-press at 120℃ and 0.2MPa for 10s to produce a product with a basis weight of 100g / m³. 2 The meltblown fabric is rolled with a reduction rate of 50% to make it more compact, and then crushed to obtain meltblown fabric fluff with a particle size controlled at about 1mm. PP is placed in a meltblown machine, melted and plasticized by a screw extruder, and then filtered. After filtration, it is sent to the meltblown die by a metering pump for melt extrusion and stretching at 250℃ to form PP meltblown fibers on a receiving curtain. Below the meltblown die, a PET hollow fiber skeleton is introduced, and the PP meltblown fibers and meltblown fabric fluff are directly deposited and embedded in the PET fiber skeleton to produce a low-frequency sound-absorbing layer with a basis weight of 350g / m². 2The thickness is 10mm, the mass ratio of PP, PET hollow fiber skeleton and meltblown fabric pile is 3:1:0.2, and the melt index of PP is 1500g / 10min. S3. PP is placed in a meltblown machine, melted and plasticized by a screw extruder, and then filtered. After filtration, it is pumped to the meltblown die by a metering pump for melt extrusion. The PP is stretched under a 245°C airflow to form PP meltblown fibers on a receiving curtain. Below the meltblown die, a PET hollow fiber skeleton is introduced, and the PP meltblown fibers are directly deposited and embedded into the PET fiber skeleton to obtain a high-frequency sound-absorbing layer with a basis weight of 100 g / m². 2 The thickness is 10mm; the mass ratio of PP to PET is 3:1. S4. A low-frequency sound-absorbing layer and a high-frequency sound-absorbing layer are stacked in layers, and the outer surfaces of both are covered with non-woven fabric to obtain a sound-absorbing and sound-insulating material.

[0027] Example 3 The method for preparing the sound-absorbing and sound-insulating material in this embodiment is as follows: S1. PET is melted and fed into a spinning box, and extruded from a shaped spinneret. It is then cooled and shaped at 30°C, stretched and crimped at 100°C with a stretch ratio of 2.6 times, and heat-set at 120°C to obtain a PET hollow fiber skeleton with a fineness of 6.67 dtex.

[0028] S2. Place the PP in a single-screw extruder with a barrel temperature of 220℃, a die temperature of 240℃, a hot air temperature of 220℃, an air pressure of 0.1℃, a receiving distance of 10cm, and a speed of 10m / min. Then, hot-press at 120℃ and 0.2MPa for 10s to produce a product with a basis weight of 91g / m³. 2 The meltblown fabric is produced by rolling with a reduction rate of 80%, followed by crushing to obtain meltblown fabric fluff with a particle size controlled at approximately 1.5 mm. PP is placed in a meltblown machine, melted and plasticized by a screw extruder, and then filtered. After filtration, it is pumped to the meltblown die for melt extrusion and stretching at 250°C, forming PP meltblown fibers on a receiving curtain. Below the meltblown die, a PET hollow fiber skeleton is introduced, and the PP meltblown fibers and meltblown fabric fluff are directly deposited and embedded into the PET fiber skeleton to produce a low-frequency sound-absorbing layer with a basis weight of 300 g / m². 2 The thickness is 8mm, the mass ratio of PP, PET hollow fiber skeleton and meltblown fabric pile is 2:1:0.2, and the melt index of PP is 2000g / 10min.

[0029] S3. PP is placed in a meltblown machine, melted and plasticized by a screw extruder, and then filtered. After filtration, it is pumped to the meltblown die by a metering pump for melt extrusion and stretching at 280℃ to form PP meltblown fibers on a receiving curtain. Below the meltblown die, a PET hollow fiber skeleton is introduced, and the PP meltblown fibers are directly deposited and embedded in the PET fiber skeleton to obtain a high-frequency sound-absorbing layer with a basis weight of 150 g / m². 2 The thickness is 8mm; the mass ratio of PP to PET is 4:1.

[0030] S4. A low-frequency sound-absorbing layer and a high-frequency sound-absorbing layer are stacked in layers, and the outer surfaces of both are covered with non-woven fabric to obtain a sound-absorbing and sound-insulating material.

[0031] Comparative Example 1 In this comparative example, the sound-absorbing and sound-insulating materials were purchased externally. Testing revealed that they consisted of a layered low-frequency sound-absorbing layer and a high-frequency sound-absorbing layer. The high-frequency sound-absorbing layer used PET hollow fiber as a skeleton and PP meltblown fiber as the filler material within the skeleton, with a basis weight of 290 g / m². 2 The thickness is 8mm. The low-frequency sound-absorbing layer uses PET hollow fiber as the skeleton, and PP meltblown fiber as the filling material in the skeleton. Then, alumina particles with a particle size of 0.3mm are added into the pores to obtain the final product, with a basis weight of 380g / m³. 2 The thickness is 8mm.

[0032] The sound absorption and sound insulation performance of Embodiments 1 to 3 of the present invention are very similar, indicating that the adjustment of some parameters in the present invention has little impact on the overall sound absorption and sound insulation performance.

[0033] A comparison of the experimental data from Examples 1, 2, and 3 with Comparative Example 1 reveals that using PET hollow fibers as the skeleton structure, ensuring sufficient strength and stability, allows for the direct deposition and embedding of PP meltblown fibers into the PET fiber skeleton, forming a high-frequency sound-absorbing layer. (See...) Figure 3 The high-frequency sound absorption coefficient of Example 1 is slightly higher than that of Comparative Example 1, while the high-frequency sound absorption coefficients of Example 1 and Comparative Example 1 are quite similar.

[0034] The PP meltblown fibers, after being crushed or rolled into sheets, are then embedded again into the PET fiber skeleton to form a low-frequency sound-absorbing layer. See Figure 4 The low-frequency sound absorption coefficient of Example 1 in the range of 500 to 5000 Hz is significantly better than that of Comparative Example 1.

[0035] High-frequency and low-frequency sound-absorbing layers are layered and stacked to form a new sound-absorbing and sound-insulating material. A non-woven fabric is then laid on the surface. The resulting sound-absorbing and sound-insulating material not only achieves better sound absorption performance but also improves low-frequency sound absorption performance. See Figure 2The sound absorption coefficient of the sound-absorbing and sound-insulating material in Example 1 is significantly better than that in Comparative Example 1 in the range of 500–5000 Hz. See Figure 5 The sound insulation effect of the sound-absorbing and sound-insulating material in Example 1 is significantly better than that in Comparative Example 1 in the range of 2000-10000Hz, and the advantage is more obvious at higher frequencies.

[0036] Obviously, the above embodiments are merely examples to clearly illustrate the embodiments of the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all embodiments here. However, these obvious variations or modifications derived from the spirit of the present invention are still within the protection scope of the present invention.

Claims

1. A sound-absorbing and sound-insulating material, characterized in that, It is made by layering at least one high-frequency sound-absorbing layer and at least one low-frequency sound-absorbing layer; the high-frequency sound-absorbing layer is made by using PET hollow fiber as a skeleton and PP meltblown fiber as the filling material in the skeleton; the low-frequency sound-absorbing layer is made by using PET hollow fiber as a skeleton, PP meltblown fiber as the filling material in the skeleton, and then adding meltblown fabric fibers into the pores.

2. The sound-absorbing and sound-insulating material according to claim 1, characterized in that, The meltblown fabric fleece is made of PP through meltblowing, with a basis weight of 30-150 g / m². 2 The meltblown fabric is then directly crushed or crushed into meltblown fabric fibers with a particle size of 0.5 to 2 mm after rolling.

3. The sound-absorbing and sound-insulating material according to claim 1, characterized in that, The PET hollow fiber skeleton of the high-frequency sound-absorbing layer and the low-frequency sound-absorbing layer has a fineness of 1.5 to 6 dtex.

4. The sound-absorbing and sound-insulating material according to claim 1, characterized in that, The mass ratio of PP to PET in the high-frequency sound-absorbing layer is 2-4:1, and the mass ratio of PP, PET, and meltblown fabric fibers in the low-frequency sound-absorbing layer is 2-4:1:0.2-0.

4.

5. The sound-absorbing and sound-insulating material according to claim 1, characterized in that, The weight of the high-frequency sound-absorbing layer is 50–300 g / m². 2 The basis weight of the low-frequency sound-absorbing layer is 150–600 g / m². 2 .

6. The sound-absorbing and sound-insulating material according to claim 1, characterized in that, The outer surface of the layered high-frequency sound-absorbing layer and the low-frequency sound-absorbing layer is covered with non-woven fabric.

7. The sound-absorbing and sound-insulating material according to claim 1, characterized in that, The method for preparing the sound-absorbing and sound-insulating material includes the following specific steps: S1. PET is melted and conveyed to the spinning box, and extruded from the irregular spinneret. It is then cooled and shaped, stretched and curled, and then shaped at 100-150℃ to obtain a PET hollow fiber skeleton. S2. PP is placed in a meltblown machine, melted and plasticized by a screw extruder and filtered. After filtration, it is sent to the meltblown die by a metering pump, melt-extruded, stretched at 200-280℃, and PP meltblown fibers are formed on the receiving curtain. Below the meltblown die, a PET hollow fiber skeleton is introduced. The PP meltblown fibers and meltblown fabric fluff are directly deposited and embedded in the PET fiber skeleton. After pressing, a low-frequency sound-absorbing layer is obtained. S3. PP is placed in a meltblown machine, melted and plasticized by a screw extruder and filtered. After filtration, it is sent to the meltblown die by a metering pump, melted and extruded, stretched at 200-280℃, and PP meltblown fibers are formed on the receiving curtain. Below the meltblown die, a PET hollow fiber skeleton is introduced, and the PP meltblown fibers are directly deposited and embedded in the PET fiber skeleton. After pressing, a high-frequency sound-absorbing layer is obtained. S4. The high-frequency sound-absorbing layer and the low-frequency sound-absorbing layer are stacked in layers, and non-woven fabric is laid on the outer surface of the stacked layer to obtain the sound-absorbing and sound-insulating material.

8. The sound-absorbing and sound-insulating material according to claim 7, characterized in that, In steps S2 and S3 above, the melt index of PP is 500-2000 g / 10 min.

9. The sound-absorbing and sound-insulating material according to claim 7, characterized in that, The method for preparing the meltblown fabric fleece is as follows: PP is placed in a single-screw extruder with a barrel temperature of 180-250℃, a die temperature of 220-260℃, a hot air temperature of 200-280℃, a receiving distance of 10-50cm, and a speed of 10-30m / min. It is then hot-pressed at 120-140℃ and 0.2-0.4MPa for 1-20s, followed by crushing or rolling and then crushing to obtain the meltblown fabric fleece.

10. The sound-absorbing and sound-insulating material according to claim 9, characterized in that, The reduction rate after rolling is 50% to 100%.

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