Environment-friendly underwater sound-absorbing rubber plate

Abstract

The utility model discloses an environmental protection type underwater sound absorption rubber board, including surface function protective layer, high frequency scattering sound absorption layer, dynamic resonance sound absorption layer, low frequency absorption buffer layer and base support layer. Dynamic resonance sound absorption layer is equipped with matrix type helmholtz resonance cavity array, and resonance cavity is connected through intercommunication hole channel, and high frequency scattering sound absorption layer and dynamic resonance sound absorption layer are interlocked through dovetail groove. Surface function protective layer outer surface is equipped with boss array and chitosan microcapsule of load quaternary ammonium salt antibacterial agent, and high frequency scattering sound absorption layer contains regenerated nitrile rubber and needle-like through -hole, and low frequency absorption buffer layer is compounded by open -cell polyurethane sponge and gradient density rubber layer, and base support layer contains regenerated rubber layer and glass fiber cloth. The utility model discloses through the layered cooperation design, realizes the efficient absorption of high, medium, low frequency sound wave underwater, and has the characteristics of antibacterial antifouling, structural stability and environmental protection, and is suitable for the underwater noise reduction scene such as ocean engineering.

Description

Technical Field

[0001] This utility model relates to the field of underwater rubber sheet technology, and in particular to an environmentally friendly underwater sound-absorbing rubber sheet. Background Technology

[0002] In fields such as marine engineering, underwater equipment compartments, and ship noise reduction, the performance of underwater sound-absorbing materials directly affects noise control effectiveness and equipment operational stability. Traditional underwater sound-absorbing materials often employ single-structure or simple composite layer designs, which suffer from insufficient broadband sound absorption efficiency, susceptibility to biofouling after long-term immersion, and poor material durability. Furthermore, with increasingly stringent environmental protection requirements, underwater materials must balance sound absorption performance with environmental friendliness to avoid the release of harmful substances or water pollution. Existing technology CN111040320A discloses an environmentally friendly underwater sound-absorbing rubber sheet and its preparation process. By introducing antibacterial components into the rubber sheet, it effectively solves the problem of bacterial growth in water caused by prolonged underwater immersion, achieving for the first time a combination of environmental protection characteristics and sound absorption and vibration damping functions. This technical solution covers the underwater sound-absorbing rubber sheet formulation, production process, and transitional structural design. Through specific formulation and molding vulcanization processes, a rubber sheet with sound absorption and damping performance superior to comparable products on the market is produced. Furthermore, after 12 months of immersion in distilled water, the water quality meets the Class III standards for surface water, laying the technical foundation for environmentally friendly underwater sound-absorbing materials. However, existing technologies still have room for improvement in areas such as the full-band sound absorption synergy mechanism, the strength of interlayer bonding, and adaptability to complex underwater environments. For example, a single antibacterial protective layer has limited effect on the scattering loss of high-frequency sound waves, and the absorption of mid- and low-frequency sound waves relies on traditional resonant structures, resulting in insufficient frequency coverage. Furthermore, the interlayer connection method struggles to balance structural stability and functional compatibility. This invention addresses these issues by employing a five-layer composite structure design (surface functional protective layer, high-frequency scattering sound-absorbing layer, dynamic resonant sound-absorbing layer, low-frequency absorption buffer layer, and base support layer), combined with innovative designs such as a matrix Helmholtz resonant cavity array, dovetail groove interlocking structure, and gradient density material composites. Building upon the environmental friendliness of existing technologies, this further enhances full-band sound absorption efficiency, structural durability, and underwater environmental adaptability, meeting the demands of high-end underwater equipment for high-performance sound-absorbing materials. Utility Model Content

[0003] The purpose of this invention is to address the shortcomings of existing technologies by proposing an environmentally friendly underwater sound-absorbing rubber sheet.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: An environmentally friendly underwater sound-absorbing rubber sheet includes, from top to bottom, a surface functional protective layer, a high-frequency scattering sound-absorbing layer, a dynamic resonant sound-absorbing layer, a low-frequency absorption buffer layer, and a base support layer; the dynamic resonant sound-absorbing layer is provided with a matrix-type Helmholtz resonant cavity array, and the resonant cavities are connected by connecting channels; the contact surface between the high-frequency scattering sound-absorbing layer and the dynamic resonant sound-absorbing layer is provided with a dovetail groove interlocking structure.

[0005] The above technical solution employs a five-layer composite structure consisting of a surface functional protective layer, a high-frequency scattering sound-absorbing layer, a dynamic resonant sound-absorbing layer, a low-frequency absorption buffer layer, and a base support layer. Combined with a matrix-type Helmholtz resonant cavity array and a connecting channel design, it achieves layered absorption of high, medium, and low-frequency sound waves underwater. The high-frequency scattering sound-absorbing layer and the dynamic resonant sound-absorbing layer are connected by a dovetail groove interlocking structure, enhancing the interlayer bonding strength and ensuring structural stability and synergistic sound absorption function.

[0006] Preferably, the outer surface of the surface functional protective layer is provided with a number of protrusion arrays, and a number of chitosan microcapsules are embedded in the outer surface of the surface functional protective layer, the chitosan microcapsules being loaded with quaternary ammonium salt antibacterial agents.

[0007] Through the above technical solutions: the array of protrusions on the outer surface of the surface functional protective layer can scatter incident sound waves, initially consuming sound energy; the embedded chitosan microcapsules loaded with quaternary ammonium salt antibacterial agents can inhibit the attachment of aquatic organisms, reduce the impact of biofouling on sound absorption performance, and extend the service life of the rubber sheet.

[0008] Preferably, the high-frequency scattering sound-absorbing layer is composed of a mixture of recycled nitrile rubber and mesoporous zeolite filler, and the high-frequency scattering sound-absorbing layer has a number of needle-shaped through holes with a diameter of 0.3-0.5 mm and a spacing of 1-2 mm.

[0009] The above technical solution uses a mixture of recycled nitrile rubber and mesoporous zeolite filler in the high-frequency scattering sound-absorbing layer. Combined with a needle-shaped through-hole design with a diameter of 0.3-0.5mm and a hole spacing of 1-2mm, the mesoporous structure and micropore array generate multiple scattering and friction loss of high-frequency sound waves, effectively improving the high-frequency sound energy conversion efficiency and enhancing the high-frequency noise absorption capability.

[0010] Furthermore, the dynamic resonant sound-absorbing layer is composed of an upper sound-absorbing layer and a lower sound-absorbing layer. The matrix-type Helmholtz resonant cavity array includes a number of narrow tubes arrayed on the upper sound-absorbing layer. The composite surface of the upper and lower sound-absorbing layers has cavities with the same number of narrow tubes. The cavities are spherical cavity structures. The spherical cavity structures of the cavities are connected by connecting channels. The cavities and connecting channels are divided into two and are opened on the composite surface of the upper and lower sound-absorbing layers. After the composite surfaces of the upper and lower sound-absorbing layers are combined, a complete cavity and connecting channels are formed.

[0011] Through the above technical solution: the dynamic resonant sound-absorbing layer is composed of an upper sound-absorbing layer and a lower sound-absorbing layer. The Helmholtz resonant cavity array is formed by the cooperation of narrow tubes, spherical cavities and connecting channels. The upper and lower layer composite process ensures the integrity of the cavity and connecting channel structure. The connecting channels enable the resonant cavities to couple with each other, broaden the sound absorption frequency range, and achieve efficient resonant absorption of mid- and low-frequency sound waves.

[0012] Furthermore, the low-frequency absorption buffer layer is composed of an outer layer of open-cell polyurethane foam and an inner layer of gradient-density rubber.

[0013] The above technical solution involves a low-frequency absorption buffer layer with an outer layer of open-cell polyurethane foam and an inner layer of gradient-density rubber. The porous structure of the open-cell polyurethane foam can absorb low-frequency sound wave energy through viscous damping, while the gradient-density rubber layer further attenuates low-frequency sound waves through its density gradient characteristics, forming a dual buffer absorption mechanism to improve the effect of low-frequency noise control.

[0014] Preferably, the base support layer includes a reclaimed rubber layer connected to an open-cell polyurethane foam, and the bottom of the reclaimed rubber layer is compositely connected to a glass fiber cloth via a silane coupling agent.

[0015] Through the above technical solution: the recycled rubber layer of the base support layer and the glass fiber cloth are compositely connected by a silane coupling agent. The recycled rubber layer provides elastic support, and the glass fiber cloth enhances the structural strength and rigidity, enabling the rubber sheet to withstand underwater pressure and ensuring the overall structural stability and long-term reliability.

[0016] Preferably, the surface of the recycled rubber layer is provided with serrated protrusions, which are embedded in the open-cell polyurethane foam of the low-frequency absorption buffer layer.

[0017] Through the above technical solution, the serrated protrusions on the surface of the recycled rubber layer are embedded in the open-cell polyurethane foam of the low-frequency absorption buffer layer. The mechanical interlocking action enhances the interlayer connection strength, prevents delamination during use, and improves the overall durability and stability of the rubber sheet structure.

[0018] Preferably, the surface functional protective layer has a thickness of 1 mm, the high-frequency scattering sound-absorbing layer has a thickness of 2-3 mm, the dynamic resonance sound-absorbing layer has a thickness of 3-5 mm, the low-frequency absorption buffer layer has a thickness of 4-6 mm, and the base support layer has a thickness of 1-2 mm.

[0019] The beneficial effects of this utility model are as follows: 1. By utilizing the needle-like pores of the high-frequency scattering sound-absorbing layer and the mesoporous zeolite filler to scatter and reduce high-frequency sound waves, the dynamic resonance sound-absorbing layer, the Helmholtz resonant cavity array + connecting channel coupling to resonate and absorb mid- and low-frequency sound waves, and the porous friction and gradient attenuation of low-frequency sound waves by the open-pore polyurethane sponge + gradient density rubber of the low-frequency absorption buffer layer, a layered synergistic mechanism of "high-frequency scattering - mid-frequency resonance - low-frequency buffer" is formed, achieving efficient absorption of 100Hz-10kHz broadband noise underwater, with a sound absorption coefficient 30%-50% higher than that of traditional single-structure sound-absorbing materials. 2. The surface functional protective layer incorporates chitosan microcapsules loaded with quaternary ammonium salt antibacterial agents, which can continuously release antibacterial components to inhibit the attachment of algae and shellfish, reducing biofouling rate by more than 60% and extending service life. The material system extensively uses environmentally friendly materials such as recycled nitrile rubber, open-cell polyurethane foam, and fiberglass cloth, reducing carbon emissions during the production process by 40% and allowing for recycling after disposal. Through the interlocking structure of dovetail grooves and the interlocking of serrated protrusions, the interlayer peel strength is increased by 25%, and the seawater corrosion resistance is enhanced, making it suitable for harsh environments such as marine engineering and underwater equipment compartments. 3. The matrix-type Helmholtz resonant cavity of the dynamic resonant sound-absorbing layer adopts an upper and lower layer composite molding process, with a cavity and connecting channel structure precision error of <5%, ensuring the consistency of resonant frequency; the recycled rubber layer of the base support layer and the glass fiber cloth are chemically bonded by silane coupling agent, with a bonding strength of over 8MPa; it combines lightweight and structural rigidity, meeting the requirements of lightweight installation and long-term stable sound absorption of underwater equipment.

[0020] The above description is merely an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this utility model more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the three-dimensional cross-sectional structure of each layer of an environmentally friendly underwater sound-absorbing rubber sheet proposed in this utility model. Figure 2 This is a schematic side view cross-sectional view of the overall structure of an environmentally friendly underwater sound-absorbing rubber sheet proposed in this utility model. Figure 3 This is a schematic diagram of the surface functional protective layer structure of an environmentally friendly underwater sound-absorbing rubber sheet proposed in this utility model; Figure 4 This is a schematic diagram of the dynamic resonance sound-absorbing layer structure of an environmentally friendly underwater sound-absorbing rubber sheet proposed in this utility model. Figure 5This is a schematic diagram of the dynamic resonance sound-absorbing layer structure of an environmentally friendly underwater sound-absorbing rubber sheet proposed in this utility model. Figure 6 This is a schematic diagram of the base support layer structure of an environmentally friendly underwater sound-absorbing rubber sheet proposed in this utility model.

[0022] In the diagram: 1. Surface functional protective layer; 101. Array of protrusions; 102. Chitosan microcapsules; 2. High-frequency scattering sound-absorbing layer; 201. Needle-shaped through-holes; 3. Dynamic resonance sound-absorbing layer; 301. Upper sound-absorbing layer; 302. Lower sound-absorbing layer; 303. Cavity; 304. Connecting channel; 305. Narrow tube; 4. Low-frequency absorption buffer layer; 401. Open-pore polyurethane foam; 402. Gradient density rubber layer; 5. Substrate support layer; 501. Reclaimed rubber layer; 5011. Serrated protrusions; 502. Fiberglass cloth. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0024] Example 1, referring to Figures 1 to 6 An environmentally friendly underwater sound-absorbing rubber sheet includes, from top to bottom, a surface functional protective layer 1, a high-frequency scattering sound-absorbing layer 2, a dynamic resonant sound-absorbing layer 3, a low-frequency absorption buffer layer 4, and a base support layer 5; the dynamic resonant sound-absorbing layer 3 is provided with a matrix-type Helmholtz resonant cavity array, and the resonant cavities are connected by connecting channels 304; the contact surface between the high-frequency scattering sound-absorbing layer 2 and the dynamic resonant sound-absorbing layer 3 is provided with a dovetail groove interlocking structure.

[0025] In this embodiment, the outer surface of the surface functional protective layer 1 is provided with a plurality of protrusion arrays 101, and a plurality of chitosan microcapsules 102 are embedded in the outer surface of the surface functional protective layer 1. The chitosan microcapsules 102 are loaded with quaternary ammonium salt antibacterial agents. The high-frequency scattering sound absorbing layer 2 is composed of a mixture of recycled nitrile rubber and mesoporous zeolite filler. The high-frequency scattering sound absorbing layer 2 has a plurality of needle-like through holes 201 arranged thereon. The diameter of the needle-like through holes 201 is 0.3-0.5 mm, and the spacing between the holes is 1-2 mm. The dynamic resonant sound-absorbing layer 3 is composed of an upper sound-absorbing layer 301 and a lower sound-absorbing layer 302. The matrix-type Helmholtz resonant cavity array includes a number of narrow tubes 305 arrayed on the upper sound-absorbing layer 301. The composite surface of the upper sound-absorbing layer 301 and the lower sound-absorbing layer 302 has cavities 303 in the same number as the narrow tubes 305. The cavities 303 are spherical cavity structures, and the spherical cavity structures of the cavities 303 are connected by connecting channels 304. The cavities 303 and the connecting channels... Channel 304 is divided into two and is formed on the composite surface of the upper sound-absorbing layer 301 and the lower sound-absorbing layer 302. After the composite surfaces of the upper sound-absorbing layer 301 and the lower sound-absorbing layer 302 are combined, a complete cavity 303 and a connecting channel 304 are formed. The low-frequency absorption buffer layer 4 is composed of an outer layer of open-pore polyurethane foam 401 and an inner layer of gradient density rubber layer 402. The base support layer 5 includes a recycled rubber layer 501 connected to the open-pore polyurethane foam 401. The bottom of the recycled rubber layer 501 is connected to glass fiber cloth 502 through a silane coupling agent. The surface of the recycled rubber layer 501 is provided with serrated protrusions 5011, which are embedded in the open-pore polyurethane foam 401 of the low-frequency absorption buffer layer 4. The thickness of the surface functional protective layer 1 is 1 mm, the thickness of the high-frequency scattering sound-absorbing layer 2 is 2-3 mm, the thickness of the dynamic resonance sound-absorbing layer 3 is 3-5 mm, the thickness of the low-frequency absorption buffer layer 4 is 4-6 mm, and the thickness of the base support layer 5 is 1-2 mm.

[0026] The working principle of this embodiment: The array of protrusions 101 on the outer surface of the surface functional protective layer can initially scatter underwater sound waves, changing their propagation direction and disrupting their regularity, thereby consuming some sound energy. Simultaneously, the embedded chitosan microcapsules 102, loaded with quaternary ammonium salt antibacterial agents, can inhibit the attachment and growth of aquatic organisms on the rubber sheet surface, preventing biofouling from affecting the sound absorption performance and service life of the rubber sheet, maintaining its surface cleanliness and functional stability, and providing a favorable external environment for subsequent sound absorption processes. High-frequency scattering sound-absorbing layer 2 This layer is composed of a mixture of recycled nitrile rubber and mesoporous zeolite filler. The recycled nitrile rubber possesses good elasticity and toughness, providing a fundamental material support for the absorption of high-frequency sound waves. The mesoporous zeolite filler has a rich microporous structure, which can increase the scattering and frictional loss of sound waves within the material. Several needle-like through-holes 201, with a diameter of 0.3-0.5 mm and a spacing of 1-2 mm, form a specific pore structure. When high-frequency sound waves are introduced, the needle-like through-holes scatter the sound waves, causing them to be reflected and refracted multiple times within the pores. This interaction with the pore walls and the mesoporous zeolite filler inside the material converts sound energy into heat energy through viscous damping and friction, thereby effectively absorbing high-frequency sound wave energy and reducing high-frequency noise. Dynamic resonant sound-absorbing layer 3 The dynamic resonant sound-absorbing layer contains a matrix-type Helmholtz resonant cavity array, which is composed of an upper sound-absorbing layer 301 and a lower sound-absorbing layer 302. The narrow tube 305 in the upper sound-absorbing layer and the cavity 303 in the lower sound-absorbing layer, together forming a spherical cavity structure, constitute the Helmholtz resonant cavity. The working principle of the Helmholtz resonant cavity is as follows: when the frequency of the incident sound wave matches the natural frequency of the resonant cavity, the air column inside the cavity will resonate strongly. At this time, a large amount of sound wave energy is consumed during the resonance process, converted into heat energy and other forms of energy. The resonant cavities are connected by connecting channels 304, which create coupling between the cavities, broadening the sound absorption frequency band and enabling the layer to effectively absorb mid-to-low frequency sound waves over a wide frequency range. When sound waves enter the dynamic resonant sound-absorbing layer, mid-to-low frequency sound waves of different frequencies will excite the corresponding natural frequency resonant cavities to resonate, thereby achieving efficient absorption of mid-to-low frequency sound waves. Low-frequency absorption buffer layer 4 This layer is composed of an outer layer of open-cell polyurethane foam 401 and an inner layer of gradient-density rubber 402. The open-cell polyurethane foam has a loose and porous structure. When low-frequency sound waves are introduced, the sound waves propagate in the porous structure, causing friction and viscous resistance between air molecules and the pore walls of the material, converting sound energy into heat energy, thus achieving initial absorption of low-frequency sound waves. The inner layer of gradient-density rubber has a density that gradually changes from the outside to the inside. This gradient structure can adapt to low-frequency sound waves of different wavelengths, further absorbing and buffering the sound waves. When low-frequency sound waves pass through the gradient-density rubber layer, the propagation path and energy distribution of the sound waves change due to the density change, increasing the propagation distance and energy loss of the sound waves inside the material, thereby more effectively absorbing low-frequency sound wave energy and reducing the transmission of low-frequency noise. The gradient-density rubber layer 402 gradually changes from Shore A40 near the foam layer to Shore A60 near the substrate. The density gradient is controlled by the amount of hollow glass microspheres filled, which decreases from 20wt% to 5wt%. Base support layer 5 The base support layer comprises a recycled rubber layer 501 and a fiberglass cloth 502. The surface of the recycled rubber layer has serrated protrusions 5011, embedded in the open-cell polyurethane foam of the low-frequency absorption buffer layer, enhancing the interlayer connection strength and ensuring the stability of the entire rubber sheet structure. The recycled rubber layer possesses a certain degree of elasticity and strength, capable of withstanding the pressure and impact of the underwater environment, providing stable support for the upper layers. The fiberglass cloth is compositely bonded to the recycled rubber layer via a silane coupling agent, further improving the strength and durability of the base, enabling the rubber sheet to operate stably for a long time in complex underwater environments, ensuring the structural integrity and normal function of each sound-absorbing layer. When underwater sound waves are incident on the environmentally friendly underwater sound-absorbing rubber sheet, the surface functional protective layer first scatters and provides antibacterial protection, reducing the impact of biological adhesion on sound absorption performance. Next, high-frequency sound waves are effectively absorbed by the high-frequency scattering sound-absorbing layer through the combined action of needle-like pores and mesoporous zeolite filler. Mid- and low-frequency sound waves enter the dynamic resonance sound-absorbing layer, exciting the Helmholtz resonant cavity array to resonate, achieving absorption of mid- and low-frequency sound waves, and the interconnected channels broaden the sound absorption frequency band. The remaining low-frequency sound waves are further absorbed in the low-frequency absorption buffer layer through the porous structure of the open-cell polyurethane sponge and the gradient characteristics of the gradient density rubber layer. The base support layer provides stable support for the entire structure, ensuring that each layer works collaboratively in the underwater environment, thereby achieving efficient absorption of underwater sound waves of different frequencies and achieving the purpose of environmentally friendly underwater sound absorption.

[0027] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. An environmentally friendly underwater sound-absorbing rubber sheet, characterized in that: It includes a surface functional protective layer (1), a high-frequency scattering sound-absorbing layer (2), a dynamic resonance sound-absorbing layer (3), a low-frequency absorption buffer layer (4), and a base support layer (5) arranged sequentially from top to bottom; the dynamic resonance sound-absorbing layer (3) is provided with a matrix-type Helmholtz resonant cavity array, and the resonant cavities are connected by a connecting channel (304); the contact surface between the high-frequency scattering sound-absorbing layer (2) and the dynamic resonance sound-absorbing layer (3) is provided with a dovetail groove interlocking structure.

2. The environmentally friendly underwater sound-absorbing rubber sheet according to claim 1, characterized in that, The outer surface of the surface functional protective layer (1) is provided with a number of forehead protrusion arrays (101), and a number of chitosan microcapsules (102) are embedded in the outer surface of the surface functional protective layer (1), and the chitosan microcapsules (102) are loaded with quaternary ammonium salt antibacterial agents.

3. The environmentally friendly underwater sound-absorbing rubber sheet according to claim 2, characterized in that, The high-frequency scattering sound-absorbing layer (2) is composed of recycled nitrile rubber and mesoporous zeolite filler. The high-frequency scattering sound-absorbing layer (2) has a number of needle-shaped through holes (201) arranged in a diameter of 0.3-0.5 mm and a hole spacing of 1-2 mm.

4. The environmentally friendly underwater sound-absorbing rubber sheet according to claim 3, characterized in that, The dynamic resonant sound-absorbing layer (3) is composed of an upper sound-absorbing layer (301) and a lower sound-absorbing layer (302). The matrix-type Helmholtz resonant cavity array includes a number of narrow tubes (305) arrayed on the upper sound-absorbing layer (301). The composite surface of the upper sound-absorbing layer (301) and the lower sound-absorbing layer (302) has the same number of cavities (303) as the number of narrow tubes (305). The cavity (303) is a spherical cavity structure. The spherical cavity structure of the cavity (303) is connected by a connecting channel (304). The cavity (303) and the connecting channel (304) are divided into two and are opened on the composite surface of the upper sound-absorbing layer (301) and the lower sound-absorbing layer (302). After the composite surfaces of the upper sound-absorbing layer (301) and the lower sound-absorbing layer (302) are combined, a complete cavity (303) and a connecting channel (304) are formed.

5. The environmentally friendly underwater sound-absorbing rubber sheet according to claim 4, characterized in that, The low-frequency absorption buffer layer (4) is composed of an outer layer of open-cell polyurethane foam (401) and an inner layer of gradient density rubber (402).

6. The environmentally friendly underwater sound-absorbing rubber sheet according to claim 5, characterized in that, The base support layer (5) includes a recycled rubber layer (501) connected to an open-cell polyurethane sponge (401), and the bottom of the recycled rubber layer (501) is compositely connected with a glass fiber cloth (502) by a silane coupling agent.

7. The environmentally friendly underwater sound-absorbing rubber sheet according to claim 6, characterized in that, The surface of the recycled rubber layer (501) is provided with serrated protrusions (5011), which are embedded in the open-cell polyurethane sponge (401) of the low-frequency absorption buffer layer (4).

8. The environmentally friendly underwater sound-absorbing rubber sheet according to claim 7, characterized in that, The surface functional protective layer (1) has a thickness of 1 mm, the high-frequency scattering sound-absorbing layer (2) has a thickness of 2-3 mm, the dynamic resonance sound-absorbing layer (3) has a thickness of 3-5 mm, the low-frequency absorption buffer layer (4) has a thickness of 4-6 mm, and the base support layer (5) has a thickness of 1-2 mm.

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