Multi-layer lightweight sound-absorbing and sound-insulating materials

Abstract

This invention provides a multi-layered lightweight sound-absorbing and insulating material, comprising a layer of sound-absorbing cotton, a cup-shaped plastic film layer, and a plastic board layer stacked together. Multiple cup-shaped structures are arranged in an array on the cup-shaped plastic film layer. Each cup-shaped structure has a second through-hole at its bottom, and these structures are arranged periodically according to the size of the second through-hole. Within each arrangement cycle, there are multiple second through-holes with different diameters. The cup-shaped structures corresponding to the different diameters of the second through-holes form multiple Helmholtz resonators with different resonance frequencies. This invention forms multiple Helmholtz resonators with different resonance frequencies through multiple cup-shaped structures with different through-hole diameters. The coupling effect of the perforated cup-shaped structures with different resonance frequencies generates a continuous and wide mid-to-low frequency resonant sound-absorbing band. While possessing a certain high-frequency sound absorption capability, it significantly improves the low-to-mid frequency sound absorption and insulation capability. Compared with traditional porous sound-absorbing materials such as felt fibers and sound-absorbing cotton, it greatly improves the sound absorption and insulation capability at the same thickness.

Description

Technical Field

[0001] This invention relates to the field of sound-absorbing and sound-insulating materials, specifically to a multi-layered lightweight sound-absorbing and sound-insulating material, and more particularly to a multi-layered lightweight sound-absorbing and sound-insulating material suitable for the entire frequency band. Background Technology

[0002] In industrial applications, particularly in home appliances and various power machinery, noise control of key components such as fans, motors, and compressors primarily relies on porous sound-absorbing materials like felt fibers and sound-absorbing cotton. These materials are relatively cost-effective and have become the mainstream noise control solution.

[0003] However, the aforementioned materials have limited sound absorption and insulation performance in the low-to-mid frequency range, making it difficult to meet increasingly stringent noise control standards. To improve low-to-mid frequency suppression, these materials typically rely on increasing their thickness and density. However, excessively thick sound-absorbing layers cannot be accommodated in confined spaces, and excessive thickness and weight make it difficult to adhere to irregularly shaped sound sources. Furthermore, increased thickness and weight directly drive up material costs. Therefore, achieving efficient low-to-mid frequency noise suppression within confined spaces is a pressing technical problem that needs to be solved in this field. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a multi-layer lightweight sound-absorbing and sound-insulating material.

[0005] The multilayer lightweight sound-absorbing and sound-insulating material provided by the present invention includes a sound-absorbing cotton layer, a cup-shaped plastic film layer, and a plastic board layer stacked sequentially from top to bottom; The cup-shaped plastic film layer has multiple cup-shaped structures with their bottoms facing the sound-absorbing cotton layer arranged in an array, and each cup-shaped structure has a second through hole at its bottom. Multiple cup-shaped structures are arranged periodically according to the size of the second through hole diameter. In each arrangement period, there are multiple second through holes with different diameters, so that the cup-shaped structures corresponding to the second through holes with different diameters form multiple Helmholtz resonators with different resonance frequencies.

[0006] Preferably, the cup-shaped structures on the cup-shaped plastic film layer are of the same size.

[0007] Preferably, the cross-section of the cup-shaped structure is square, with its lower side length L being greater than or equal to 10 mm and less than or equal to 50 mm, and the bottom spacing D between adjacent cup-shaped structures being greater than or equal to 1 mm and less than or equal to 10 mm.

[0008] Preferably, the height H of the cup-shaped structure is greater than or equal to 10 mm and less than or equal to 40 mm.

[0009] Preferably, the draft angle α of the cup-shaped structure is greater than or equal to 1.5° and less than or equal to 30°.

[0010] Preferably, the thickness h0 of the plastic film between the sidewall and bottom of the cup-shaped structure is greater than or equal to 0.3 mm and less than or equal to 2 mm.

[0011] Preferably, the sound-absorbing cotton layer has a first through hole directly above the second through hole; The diameter d2 of the first through hole is greater than or equal to the diameter d1 of the second through hole. In the projection from a top view angle, the first through hole does not obstruct the second through hole.

[0012] Preferably, the diameter d2 of the first through hole is greater than or equal to 5 mm and less than or equal to 10 mm, and the diameter d1 of the second through hole is greater than or equal to 0.1 mm and less than or equal to 5 mm. Within a cup-shaped structure arrangement cycle, the diameter d1 of the second through hole is uniformly distributed within the range of 0.1mm-5mm, so that multiple cup-shaped structures form a Helmholtz resonator with a continuous resonant frequency.

[0013] Preferably, the thickness h2 of the sound-absorbing cotton layer is greater than or equal to 3 mm and less than or equal to 20 mm, and the thickness h1 of the plastic board layer is greater than or equal to 0.3 mm and less than or equal to 3 mm.

[0014] Preferably, the plurality of first through holes on the sound-absorbing cotton layer have the same diameter and are arranged one-to-one above the second through holes.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention periodically opens multiple cup-shaped structures with different apertures on a cup-shaped plastic film layer located in the middle layer, so that the cup-shaped structures can form Helmholtz resonators with different resonance frequencies. The coupling effect of the perforated cup-shaped structures with different resonance frequencies generates a continuous and wide resonant sound-absorbing band, which greatly improves the sound absorption and insulation ability in the low and mid frequencies. Compared with traditional porous sound-absorbing materials such as felt fibers and sound-absorbing cotton, it greatly improves the sound absorption and insulation ability at the same thickness.

[0016] 2. The present invention covers the surface of the cup-shaped structure arranged in an array with a perforated sound-absorbing cotton layer, which can prevent the sound-absorbing cotton layer from blocking the through holes of the cup-shaped structure and affecting its low-frequency resonance sound absorption effect. At the same time, it can supplement the high-frequency sound absorption capacity without affecting the low-frequency sound absorption effect. Attached Figure Description

[0017] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of an explosion from one angle. Figure 3 This is an explosion diagram from another angle of the present invention; Figure 4 This is a comparison chart of the sound absorption rates of the present invention and traditional polyurethane sound-absorbing cotton.

[0018] The diagram shows: 1. Sound-absorbing cotton layer, 11. First through hole, 2. Cup-shaped plastic film layer, 21. Cup-shaped structure, 22. Second through hole, 3. Plastic board layer. Detailed Implementation

[0019] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0020] This invention discloses a multilayer lightweight sound-absorbing and insulating material. By periodically opening multiple cup-shaped structures with different pore sizes on a cup-shaped plastic film layer located in the middle layer, the cup-shaped structures can form Helmholtz resonators with different resonance frequencies. The coupling effect of the perforated cup-shaped structures with different resonance frequencies generates a continuous and wide resonant sound-absorbing band, which greatly improves the sound absorption and insulation capability at low and mid frequencies. Compared with traditional porous sound-absorbing materials such as felt fibers and sound-absorbing cotton, it greatly improves the sound absorption and insulation capability at the same thickness.

[0021] The multilayer lightweight sound-absorbing and sound-insulating material provided by the present invention, such as Figure 1 As shown, it includes, from top to bottom, a sound-absorbing cotton layer 1, a cup-shaped plastic film layer 2, and a plastic board layer 3, stacked sequentially; as Figure 2 , Figure 3 As shown, multiple cup-shaped structures 21 with their bottoms protruding towards the sound-absorbing cotton layer 1 are arranged in an array on the cup-shaped plastic film layer 2. Each cup-shaped structure 21 has a second through hole 22 at its bottom. The multiple cup-shaped structures 21 are arranged periodically according to the size of the second through hole 22. Within each arrangement cycle, multiple second through holes 22 of varying diameters are included, allowing the cup-shaped structures 21 corresponding to these holes to form Helmholtz resonators with different resonant frequencies. Each perforated cup-shaped structure 21 acts as a Helmholtz resonator. Within a single arrangement cycle, the perforated cup-shaped structures 21 with different resonant frequencies couple to create a continuous and broad resonant sound-absorbing band, significantly enhancing the low-to-mid-frequency sound absorption and insulation capabilities. The periodic arrangement of the array units reduces the size of the production molds for these sound-absorbing and insulating materials, thereby lowering production costs.

[0022] Specifically, the resonant frequency of the cup-shaped structure 21 The following formula can be used for calculation, where, The speed of sound in air. The diameter of the second through hole 22 The depth of the second through hole 22 (i.e., the thickness of the plastic film at the bottom of the cup-shaped structure 21). The volume of the cup-shaped structure 21:

[0023] Near the resonant frequency, the air in the grid expands and contracts, causing the air in the second through-hole 22 to vibrate violently. Since the size of the second through-hole 22 is similar to the thickness of the airflow boundary layer on the hole wall at this time, the thermal viscosity effect of the air causes the air in the second through-hole 22 to rub strongly against the wall of the second through-hole 22, resulting in sound energy dissipation and sound absorption. In a preferred embodiment, according to the required sound absorption frequency (especially low-mid frequency: 400-1600Hz), an array unit (such as 6×6, 6×8, 8×8, etc.) is modulated. The size of the second through-hole 22 of each cup-shaped structure 21 in this unit is different. Then, the resonant sound absorption array unit is arranged periodically. The perforated cup-shaped structures 21 with different resonant frequencies couple to produce a continuous and wide resonant sound absorption band, which greatly improves the sound absorption and insulation capacity of low-mid frequency. At the same time, covering the array surface with a perforated sound-absorbing cotton layer 1 can supplement the high-frequency sound absorption capacity without affecting the low-frequency sound absorption effect.

[0024] In a preferred embodiment, multiple cup-shaped structures 21 on the cup-shaped plastic film layer 2 have identical dimensions. The cross-section of each cup-shaped structure 21 is square, with its lower side length L being greater than or equal to 10 mm and less than or equal to 50 mm. The bottom spacing D between adjacent cup-shaped structures 21 is greater than or equal to 1 mm and less than or equal to 10 mm. The height H of each cup-shaped structure 21 is greater than or equal to 10 mm and less than or equal to 40 mm. The draft angle α of each cup-shaped structure 21 is greater than or equal to 1.5° and less than or equal to 30°. The thickness h0 of the plastic film between the sidewall and the bottom of each cup-shaped structure 21 is greater than or equal to 0.3 mm and less than or equal to 2 mm. The sound-absorbing cotton layer 1 has a first through-hole 11 directly above the second through-hole 22. The diameter d2 of the first through-hole 11 is the same as that of the second through-hole 22 and is greater than or equal to the diameter d1 of the second through-hole 22. In a top-view projection, the first through-hole 11 does not obstruct the second through-hole 22, thus preventing it from affecting the low-frequency resonance sound absorption effect. The diameter d2 of the first through-hole 11 is greater than or equal to 5 mm and less than or equal to 10 mm, and the diameter d1 of the second through-hole 22 is greater than or equal to 0.1 mm and less than or equal to 5 mm. Within a cup-shaped structure 21 arrangement cycle, the diameter d1 of the second through-hole 22 is uniformly distributed within the range of 0.1 mm to 5 mm, so that multiple cup-shaped structures 21 form a Helmholtz resonator with a continuous resonance frequency. The thickness h2 of the sound-absorbing cotton layer 1 is greater than or equal to 3 mm and less than or equal to 20 mm, and the thickness h1 of the plastic plate layer 3 is greater than or equal to 0.3 mm and less than or equal to 3 mm.

[0025] Example 1 like Figure 4 As shown, this embodiment provides the sound absorption performance of the above sound-absorbing and insulating material in the 400-1600Hz frequency band. Specifically, using the sound-absorbing and insulating material provided by this invention, the height of the cup-shaped structure 21 is 20mm, the thickness of the sound-absorbing cotton layer 1 is 5mm, the overall thickness of the sound-absorbing and insulating material is 25mm, the lower side length of the cup-shaped structure 21 is 40mm, the draft angle is 2°, the bottom spacing between adjacent cup-shaped structures 21 is 8mm, the aperture size of the second through hole 22 varies from 0.5mm to 5mm, the aperture of the first through hole 11 is 8mm, the thickness of the plastic plate layer 3 is 0.5mm, and its sound absorption rate is 0.6-0.8.

[0026] Comparative Example 1 This comparative example is used as a comparative example of Example 1, such as Figure 4 As shown, traditional porous sound-absorbing material (polyurethane sound-absorbing cotton) is used, with a thickness of 70mm. In the frequency range of 400-1600Hz, the sound absorption rate is 0.4-0.8.

[0027] It is known that if traditional porous sound-absorbing materials are to achieve similar sound absorption performance to the present invention in the mid-to-low frequency range, their thickness needs to reach 70mm, which is nearly 3 times greater than that of the present invention.

[0028] Comparative Example 2 This comparative example is used as a comparative example of Example 1, such as Figure 4 As shown, traditional porous sound-absorbing material (polyurethane sound-absorbing cotton) is used, with a thickness of 25mm. In the frequency band of 400-1600Hz, the sound absorption rate is 0.1-0.4.

[0029] It is known that if a traditional porous sound-absorbing material with a similar thickness to that of the present invention is used, its sound absorption rate in the mid-to-low frequency range can only reach about 0.1-0.4, and its sound absorption performance is far lower than that of the sound-absorbing material provided by the present invention.

[0030] Comparative Example 3 This comparative example is used as a comparative example of Example 1, such as Figure 4 As shown, a structure similar to that in Example 1, with a cup-shaped structure and a layer of sound-absorbing cotton 1 stacked together, except that the height of the cup-shaped structure 21 is 15mm and the diameter d1 of the second through hole 22 is greater than 5mm, the other characteristic dimensions are the same as in Example 1. Its resonant sound-absorbing band is destroyed, and it loses its advantage in mid-low frequency sound absorption performance. In the frequency band of 400-1600Hz, the sound absorption rate is only 0.1-0.2.

[0031] The above embodiments and comparative examples, using reverberation method measured sound absorption rate data, compare the effects of traditional polyurethane sound-absorbing cotton and the multi-layer lightweight sound-absorbing and insulating material provided by this invention, and demonstrate the situation that occurs when the height of the cup-shaped structure 21 is reduced to 15mm and the diameter d1 of the second through hole 22 is greater than 5mm. It can be seen that compared to traditional porous sound-absorbing materials of equal thickness, this invention has significant advantages in the mid-to-low frequency range (400-1600Hz), while retaining a certain degree of high-frequency sound absorption effect.

[0032] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0033] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A multi-layer lightweight sound-absorbing and sound-insulating material, characterized in that, It includes a sound-absorbing cotton layer (1), a cup-shaped plastic film layer (2), and a plastic board layer (3) stacked from top to bottom; The cup-shaped plastic film layer (2) has multiple cup-shaped structures (21) with their bottoms facing the sound-absorbing cotton layer (1) arranged in an array. Each cup-shaped structure (21) has a second through hole (22) at its bottom. Multiple cup-shaped structures (21) are arranged periodically according to the size of the second through hole (22). In each arrangement period, there are multiple second through holes (22) with different diameters, so that the cup-shaped structures (21) corresponding to the second through holes (22) with different diameters form multiple Helmholtz resonators with different resonance frequencies. The cross-section of the cup-shaped structure (21) is square, the length of its lower side L is greater than or equal to 10mm and less than or equal to 50mm, the bottom distance D between adjacent cup-shaped structures (21) is greater than or equal to 1mm and less than or equal to 10mm, and the height H of the cup-shaped structure (21) is greater than or equal to 10mm and less than or equal to 40mm. The sound-absorbing cotton layer (1) has a first through hole (11) directly above the second through hole (22); The diameter d2 of the first through hole (11) is greater than or equal to the diameter d1 of the second through hole (22). In the projection from the top view angle, the first through hole (11) does not obstruct the second through hole (22). The diameter d2 of the first through hole (11) is greater than or equal to 5 mm and less than or equal to 10 mm, and the diameter d1 of the second through hole (22) is greater than or equal to 0.1 mm and less than or equal to 5 mm; Within a cup-shaped structure (21) arrangement period, the diameter d1 of the second through hole (22) is uniformly distributed in the range of 0.1mm-5mm, so that multiple cup-shaped structures (21) form a Helmholtz resonator with continuous resonant frequency.

2. The multi-layer lightweight sound-absorbing and sound-insulating material according to claim 1, characterized in that, The cup-shaped plastic film layer (2) has multiple cup-shaped structures (21) of the same size.

3. The multi-layer lightweight sound-absorbing and sound-insulating material according to claim 1, characterized in that, The draft angle α of the cup-shaped structure (21) is greater than or equal to 1.5° and less than or equal to 30°.

4. The multi-layer lightweight sound-absorbing and sound-insulating material according to claim 1, characterized in that, The thickness h0 of the plastic film between the sidewall and the bottom of the cup-shaped structure (21) is greater than or equal to 0.3 mm and less than or equal to 2 mm.

5. The multi-layer lightweight sound-absorbing and sound-insulating material according to claim 1, characterized in that, The thickness h2 of the sound-absorbing cotton layer (1) is greater than or equal to 3 mm and less than or equal to 20 mm, and the thickness h1 of the plastic board layer (3) is greater than or equal to 0.3 mm and less than or equal to 3 mm.

6. The multi-layer lightweight sound-absorbing and sound-insulating material according to claim 1, characterized in that, The multiple first through holes (11) on the sound-absorbing cotton layer (1) have the same diameter and are arranged one by one above the second through hole (22).

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