Gas storage tank and its preparation method

Abstract

This invention discloses a gas storage tank and its preparation method. The gas storage tank includes a tank body and a damping coating. The damping coating is attached to the inner wall of the tank body. The damping coating includes a semi-dry first damping coating layer, a second damping coating layer, and fiberglass cloth. The fiberglass cloth is embedded between the first and second damping coating layers and fused and cured to form the final shape. The beneficial effects of this invention are: it abandons traditional passive noise reduction methods such as external sound insulation cotton and silencers, which have strong penetration and slow attenuation of low-frequency noise and have limited effectiveness. By forming a double-layer coupled structure of a metal substrate and a composite damping layer within the metal wall of the gas storage tank, firstly, when the gas storage tank is subjected to forced vibration, the bending deformation of the metal wall of the gas storage tank will cause the damping coating on the surface to undergo shear deformation synchronously; secondly, the polymer chains and filler particles inside the damping coating will generate internal friction due to relative displacement, converting the mechanical energy of the vibration into heat energy for dissipation, thereby weakening the vibration amplitude and reducing the resonance amplitude from the source.

Description

Technical Field

[0001] This invention relates to the field of air suspension manufacturing technology, and more particularly to an air tank and its manufacturing method. Background Technology

[0002] When an air suspension system is in operation, the air springs need to be inflated and deflated via an air tank. During this process, the high-pressure gas flowing through the air tank and piping generates broadband fluid noise, including low-frequency "puffing" sounds and high-frequency "hissing" sounds. This noise is transmitted to the passenger compartment through the vehicle body structure, creating unpleasant noise. Prolonged exposure can significantly increase driver and passenger fatigue, affecting ride comfort and even interfering with the driver's mood and concentration. From a commercial perspective, this noise problem reduces user perception of the brand's vehicles, thus impacting product sales and brand reputation. Therefore, effectively suppressing noise during the air tank's inflation and deflation process has become a pressing technical problem to be solved in this field.

[0003] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0004] The technical problem to be solved by this invention is to solve the noise problem generated during the filling / discharging process of the gas storage tank.

[0005] The present invention solves the above-mentioned technical problems through the following technical means:

[0006] The present invention claims to protect a gas storage tank, including a tank body and a damping coating. The damping coating is attached to the inner wall of the tank body. The damping coating includes a semi-dry first layer of damping coating, a second layer of damping coating, and fiberglass cloth. The fiberglass cloth is embedded between the first layer of damping coating and the second layer of damping coating and fused and cured to form a solid shape.

[0007] Abandoning traditional passive noise reduction methods such as external sound insulation cotton and mufflers, which have strong penetrating power and slow attenuation of low-frequency noise with limited effectiveness, this method utilizes a dual-layer coupling structure formed within the metal wall of the air tank, consisting of a metal matrix and a composite damping layer. Firstly, when the air tank is subjected to forced vibration, the bending deformation of the metal wall causes the damping coating on the surface to undergo shear deformation synchronously. Secondly, the polymer chains and filler particles within the damping coating generate internal friction due to relative displacement, converting the mechanical energy of the vibration into heat energy for dissipation, thereby weakening the vibration amplitude and reducing the resonance amplitude at its source. This method precisely addresses the pain point of resonance noise and improves acoustic performance. Resonance noise from air tanks often originates from pressure pulsations, airflow impacts, and mechanical vibrations, causing tank wall resonance and radiating low-to-mid-frequency noise outwards. For automotive air spring air tanks, this operation can directly reduce in-vehicle NVH (noise, vibration, and harshness) levels, improving driving comfort.

[0008] Preferably, the thickness of the first layer of damping coating is 1 to 1.5 mm, and the thickness of the second layer of damping coating is 0.5 to 1 mm.

[0009] Preferably, the first layer of damping coating is a water-based damping coating.

[0010] Preferably, the first layer of damping coating is a composite water-based damping coating formed by water-based acrylic copolymer emulsion, flake mica powder and / or hollow glass microspheres.

[0011] Preferably, it also includes a constraint layer, on which the damping coating is attached.

[0012] By setting a constraint layer, the intermediate damping layer is forced to produce a much more severe shear deformation than in a free state, thereby multiplying its efficiency in generating heat and dissipating energy through friction; ultimately, the gas storage tank gains stronger shock absorption and noise reduction capabilities, wider temperature adaptability, longer service life, and a smoother inner wall.

[0013] Preferably, the constraint layer is a polyurea coating.

[0014] This invention also claims a method for preparing a gas storage tank, comprising the following steps: The inner wall of the gas storage tank is coated with a first layer of damping coating with a thickness of 1 to 1.5 mm, and is in a surface-dry to semi-dry state. Fiberglass cloth is laid on the first layer of damping coating when it is in a semi-dry state. The first layer of damping coating is applied to the fiberglass cloth in a semi-dry state, and the second layer of damping coating is sprayed or scraped on, with a thickness of 0.5 to 1 mm. The first layer of damping coating, fiberglass cloth, and the second layer of damping coating are cured to form a composite damping layer.

[0015] Preferably, the semi-dry state is characterized by the first layer of damping coating being non-sticky to the touch and still slightly soft when pressed.

[0016] By using a semi-dry first layer of damping coating, the fiberglass cloth is integrated into both layers. Even when semi-dry, the coating surface still contains active functional groups, enabling it to chemically cross-link with subsequent damping coatings. Furthermore, the semi-dry damping coating retains its fluidity. When the fiberglass cloth is laid out and gently pressed, the semi-dry damping coating is squeezed into every mesh of the fiberglass cloth, even wetting each fiber bundle. Ultimately, when the second layer of damping coating is applied, the first layer fuses seamlessly with it, preventing delamination and air pockets, eliminating interfacial weaknesses, and achieving tear resistance and non-delamination. This ensures stable vibration reduction and noise reduction throughout the entire lifespan of the gas storage tank.

[0017] Preferably, the surface-dry to semi-dry state is as follows: The first layer of damping coating is a composite water-based damping coating formed by water-based acrylic copolymer emulsion, flake mica powder and / or hollow glass microspheres. After applying the first layer of damping coating at room temperature of 25°C, wait 30 to 60 minutes.

[0018] Preferably, the preparation method further includes the following step: spraying a constraint layer onto the composite damping layer.

[0019] The advantages of this invention are as follows: compared with traditional soundproofing solutions such as adding external soundproof covers or building in sound-absorbing cotton, it has at least three advantages: Advantage 1. Paint spraying can be done using automated spraying equipment, which is suitable for mass production line operations, especially for the large-scale production of automotive parts, and the construction cost is low.

[0020] Advantage 2: After the coating cures, it integrates with the tank body, eliminating the risk of peeling off and eliminating the need for regular replacement of sound-absorbing materials, resulting in low maintenance costs.

[0021] Advantage 3: The thin layer will not significantly reduce the effective volume of the gas storage tank, nor will it increase airflow resistance, thus avoiding a decrease in gas supply efficiency due to volume loss and eliminating performance loss. Attached Figure Description

[0022] Figure 1 This is a flowchart of the gas storage tank preparation method in Embodiment 1 of the present invention; Figure 2 This is a flowchart of the gas storage tank preparation method in Embodiment 4 of the present invention; Figure 3 This is a schematic diagram of the gas storage structure in Embodiment Six of the present invention; Figure 4 This is a radial cross-sectional view of the gas storage tank in Embodiment Six of the present invention; 1. Tank body; 2. Damping coating; 3. Constraint layer. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1 See Figure 1 This embodiment claims a method for manufacturing a gas storage tank, used to spray damping material inside the gas storage tank to construct a double-layer coupled structure of a metal substrate and a damping coating 2. This suppresses noise radiation from the vibration source, while improving the structural reliability of the gas storage tank and adapting it to compliance and usage requirements in vehicle scenarios. The manufacturing method includes the following steps: S1. Pre-treatment of the interior of the gas storage tank 1, used to clean the interior of the tank 1 and lay the foundation for subsequent spraying; specifically including the following steps: S10. Remove welding slag, burrs, oil stains and metal debris from the inside of the gas storage tank 1.

[0025] S11. Use masking tape and protective film to cover the non-coating surfaces of the gas tank opening and flange area to prevent contamination of the non-coating surfaces during subsequent coating.

[0026] S12. Alkaline degreasing and oil removal of the gas storage tank; specifically, immerse the gas storage tank body 1 into the degreasing tank at a temperature of 50~60℃ for 5~10 minutes, stirring the agent throughout the process to ensure that the inner wall is in full contact with the degreasing agent; after taking it out, rinse it with running water 2~3 times and check the continuity of the water film until the water film is continuous and unbroken, which is considered qualified, with no beads or oil stains.

[0027] S13. Acid etching to remove oxide film from gas storage tank; specifically, immerse the gas storage tank body 1 in environmentally friendly chromium-free etching solution at room temperature of 25~35℃ for 1~3 minutes to remove the natural oxide layer and slight rust on the aluminum alloy surface of the gas storage tank.

[0028] It is worth mentioning that the substrate should be rinsed with running pure water immediately after etching to avoid over-etching and thinning of the substrate.

[0029] S14. Chromium-free conversion film formation in the gas storage tank; specifically, immerse in a silane chromium-free conversion tank at room temperature (20~30℃) for 3~5 minutes to form a uniform colorless conversion film of 0.5~1μm; after conversion, rinse thoroughly twice with pure water to ensure no residual reagent.

[0030] S15. Hot air drying storage tank; Specifically, place tank 1 into a drying oven at a temperature of 80~100℃ and dry for 15~20 minutes to ensure that the inner wall is completely dry and there is no moisture residue; After drying, take it out and cool it to room temperature before proceeding to the next process.

[0031] It is worth mentioning that, for gas storage tanks with complex structures, steps S14 to S15 can also be performed by sandblasting with 120 to 180 mesh fine sand at a pressure of 0.3 to 0.5 MPa; dust removal and drying should be carried out immediately after sandblasting, and subsequent construction should be carried out within 2 hours to prevent secondary oxidation as an alternative solution.

[0032] S2. Spray or scrape the first layer of damping coating on the inner wall of the gas storage tank 1, with a thickness of 1mm, until the first layer of damping coating is semi-dry.

[0033] It is worth mentioning that the first layer of damping coating being in a semi-dry state means that the water-based damping coating is not sticky to the touch and still slightly soft when pressed. When the first layer of damping coating is a composite water-based damping coating formed by water-based acrylic copolymer emulsion, flake mica powder, or hollow glass microspheres, after scraping or spraying the first layer of damping coating at room temperature of 25°C, wait 30 minutes until the coating surface is dry to the point that it is not sticky to the touch and still slightly soft when pressed.

[0034] In addition, the waterborne damping coating is preferably a composite waterborne damping coating formed by waterborne acrylic copolymer emulsion, flake mica powder and / or hollow glass microspheres.

[0035] S3. When the first layer of damping coating is semi-dry, fiberglass cloth is laid on the first layer of damping coating. Specifically, the fiberglass cloth is cut according to the inner wall size of the gas storage tank, without leaving wrinkles or stretching, and is laid directly on the semi-dry first layer of damping coating. It is then gently pressed with a scraper or roller to ensure that the fiberglass cloth adheres to the first layer of damping coating without any hollow areas or curling edges, and the overlap width is ≥20mm.

[0036] S4. With the first layer of damping coating in a semi-dry state, spray or scrape the second layer of damping coating onto the fiberglass cloth. The thickness is 0.5mm. Ensure that the coating completely wets the fiberglass cloth, so that the cloth texture and yarn are not visible. The overall composite damping layer thickness reaches 1.5mm.

[0037] S5. Curing the first layer of damping coating, fiberglass cloth and the second layer of damping coating to form a composite damping layer; specifically, drying at room temperature for 24 hours.

[0038] When accelerated curing is required, baking at 60℃ for 2-4 hours can also be used. After curing, a high-toughness integral damping coating 2 is formed, and the fiberglass cloth plays a role in reinforcement, restraint, and tear resistance.

[0039] In this embodiment, firstly, the traditional passive noise reduction methods such as external sound insulation cotton and mufflers, which have strong penetrating power and slow attenuation of low-frequency noise and have limited effect, are abandoned. Instead, a double-layer coupled structure of a metal matrix and a composite damping layer is formed inside the metal wall of the gas tank. Firstly, when the gas tank is subjected to forced vibration, the bending deformation of the metal wall of the gas tank will cause the damping coating 2 on the surface to undergo shear deformation synchronously. Secondly, the polymer chains and filler particles inside the damping coating 2 will generate internal friction due to relative displacement, converting the mechanical energy of the vibration into heat energy for dissipation, thereby weakening the vibration amplitude and reducing the resonance amplitude from the source. This can typically achieve a noise reduction of 8~15dB. Through this method, the pain point of resonance noise is precisely solved, and the acoustic performance is improved. The resonance noise of the gas tank is mostly caused by pressure pulsation, airflow impact, and mechanical vibration, which causes the tank wall to resonate and radiate low- and mid-frequency noise outward. For automotive air spring gas tanks, this operation can directly reduce the NVH (noise, vibration, and acoustic roughness) level in the vehicle, improving driving comfort.

[0040] Secondly, the damping coating 2 not only reduces vibration and noise, but also forms an elastic protective layer on the inner wall of the tank 1, dispersing vibration stress and alleviating fatigue damage. It also has the functions of corrosion prevention and condensate erosion prevention. The close bond between the composite damping layer and the tank 1 strengthens the structural reliability of the tank 1 and extends its service life. Long-term resonance can cause fatigue damage to the welds and stress concentration areas of the gas storage tank. In particular, vehicle-mounted gas storage tanks need to withstand frequent pressure fluctuations and road vibrations. Resonance can easily cause weld cracking, deformation of the tank 1, and even safety hazards. This improves the fatigue life of the gas storage tank and reduces the later maintenance costs.

[0041] Thirdly, the damping coating 2 sprayed inside the gas tank does not require additional space, the thickness and weight increase of the composite damping layer are negligible, and the lightweight coating is in line with the trend of automotive lightweight design.

[0042] It is worth mentioning that the damping coating 2 must meet the GB8410 flame retardant standard and REACH environmental protection requirements to prevent the release of volatile organic compounds that pollute compressed air, ensure the normal operation of precision components such as solenoid valves and pipelines in the air spring system, and meet the requirement of compact installation space for automotive air spring tanks.

[0043] Compared with traditional soundproofing solutions such as adding external soundproof covers or building in sound-absorbing cotton, this embodiment has at least three advantages: Advantage 1. Paint spraying can be done using automated spraying equipment, which is suitable for mass production line operations, especially for the large-scale production of automotive parts, and the construction cost is low.

[0044] Advantage 2: After the coating cures, it integrates with the tank body 1, eliminating the risk of peeling off and eliminating the need for regular replacement of sound-absorbing materials, resulting in low maintenance costs.

[0045] Advantage 3: The thin layer will not significantly reduce the effective volume of the gas storage tank, nor will it increase airflow resistance, thus avoiding a decrease in gas supply efficiency due to volume loss and eliminating performance loss.

[0046] Secondly, by using a semi-dry first layer of damping coating, the fiberglass cloth is integrated into both layers. Not only does the semi-dry coating surface still contain active functional groups, enabling it to chemically cross-link with subsequent damping coatings, but the semi-dry coating also retains its fluidity. When the fiberglass cloth is laid out and gently pressed, the semi-dry damping coating is squeezed into every mesh of the fiberglass cloth, even wetting each fiber bundle. Ultimately, when the second layer of damping coating is applied, the first layer fuses seamlessly with it, preventing delamination and air pockets, eliminating interface weaknesses, and achieving tear resistance and non-delamination. This ensures stable vibration reduction and noise reduction throughout the entire lifespan of the gas storage tank.

[0047] Example 2 The difference between this embodiment and Embodiment 1 is that: In S2, the thickness of the first layer of damping coating is 1.5 mm; The first layer of damping coating is in a semi-dry state, which means that when the damping coating is water-based, after scraping or spraying the first layer of damping coating at a room temperature of 25°C, wait 60 minutes until the coating surface is dry to the point that it is not sticky to the touch and still slightly soft when pressed.

[0048] In S4, the thickness of the second damping coating is 1.0 mm, and the overall composite damping layer thickness reaches 2.5 mm. The rest is the same as in Example 1.

[0049] Example 3 The difference between this embodiment and Embodiment 1 is that: In S2, the thickness of the first layer of damping coating is 1.2 mm; The first layer of damping coating is in a semi-dry state, which means that when the damping coating is water-based, after scraping or spraying the first layer of damping coating at room temperature of 25°C, wait 45 minutes until the coating surface is dry to the point that it is not sticky to the touch and still slightly soft when pressed.

[0050] In S4, the thickness of the second damping coating is 0.7 mm, and the overall composite damping layer thickness reaches 1.9 mm. The rest is the same as in Example 1.

[0051] Example 4 See Figure 2 The difference between this embodiment and Embodiment 1 lies in two aspects: Difference 1. Damping material and constraint layer 3 are sprayed inside the gas storage tank to construct a three-layer structure consisting of a metal substrate, a glass fiber composite damping layer, and constraint layer 3.

[0052] Difference 2. It also includes S6, which is located after S5.

[0053] S6. After spraying a polyurea coating onto the composite damping layer, the coating is cured to form a constraint layer 3; specifically, a polyurea coating is sprayed onto the composite damping layer and left at room temperature for 24 hours to form a complete three-layer structure consisting of a metal substrate, a glass fiber-reinforced composite damping layer, and a constraint layer 3.

[0054] In this embodiment, by setting the constraint layer 3, the intermediate damping layer is forced to produce a severe shear deformation far exceeding that in the free state, thereby multiplying its efficiency in generating heat and dissipating energy through friction; ultimately, the gas storage tank obtains stronger shock absorption and noise reduction capabilities, wider temperature adaptability, longer service life, and a smoother inner wall.

[0055] Example 5 This embodiment requires protection of the gas storage tank, which is prepared using the coating-type gas storage tank preparation method of Embodiment 1. The gas storage tank includes a tank body 1 and a damping coating 2. The damping coating 2 is attached to the inner wall of the tank body 1. The damping coating 2 is formed by fusing and curing fiberglass cloth between two semi-dry damping coatings. The thickness of the first damping coating is 1 mm, and the thickness of the second damping coating is 0.5 mm.

[0056] Example 6 See Figure 3 and Figure 4 The difference between this embodiment and embodiment five is that the gas storage tank also includes a constraint layer 3, and the constraint layer 3 is attached to the damping coating 2. The constraint layer 3 is a polyurea coating.

[0057] Comparative Example 1 The difference between this comparative example and Example 1 is that the first layer of damping coating is in a fully dry state, which means that the first layer of damping coating is completely cured from the inside out. For example, after scraping or spraying the first layer of damping coating at room temperature of 25°C, wait 24 hours, otherwise it is the same as Example 1.

[0058] Comparative Example 2 The difference between this comparative example and Example 1 is that: The thickness of the first layer of damping coating is 0.8 mm, and the rest is the same as in Example 1.

[0059] Comparative Example 3 The difference between this comparative example and Example 1 is that: The thickness of the first layer of damping coating is 1.8 mm, and the rest is the same as in Example 1.

[0060] Comparative Example 4 The difference between this comparative example and Example 1 is that: The second layer of damping coating is 0.3 mm thick, and the rest is the same as in Example 1.

[0061] Comparative Example 5 The difference between this comparative example and Example 1 is that: The second layer of damping coating is 1.2 mm thick, and the rest is the same as in Example 1.

[0062] Experimental tests were conducted in Examples 1 to 4 and Comparative Examples 1 to 5. The test conditions were a frequency range of 100-2000Hz, and the test environment was a standard anechoic chamber. Table 1 is derived Table 1 presents the experimental test data for Examples 1 to 6 and Comparative Examples 1 to 5:

[0063] According to Table 1, we can conclude that: Firstly, applying the fiberglass cloth in a semi-dry state is crucial for achieving interlayer synergistic damping. Specifically, in Example 1, the noise reduction reached 28-32 dB, while in Comparative Example 1, where the first layer was completely dry before recoating, the noise reduction was only 18-22 dB, indicating a significant decrease in noise reduction performance. This demonstrates that the semi-dry state allows the two damping coatings to form chemical cross-links and physical interlocks through the fiberglass cloth mesh, fully leveraging the interlayer synergistic damping effect. Once the first layer is fully cured, the interfacial bonding force decreases significantly, reducing damping energy dissipation efficiency.

[0064] Secondly, there is an optimal thickness for the damping layer. Specifically, in Comparative Example 2, the first layer is too thin, resulting in insufficient basic damping energy dissipation and a noise reduction of only 15-19dB, which does not meet the preset standard.

[0065] In Comparative Example 3, the first layer was too thick, and the curing shrinkage stress caused the coating to crack, impairing the damping synergy and reducing the noise reduction to 20-24 dB.

[0066] In Comparative Example 4, the second layer is too thin to form an effective constraint damping structure, resulting in a noise reduction of only 22-25dB, which is a limited improvement.

[0067] Comparative Example 5 shows that the second layer is too thick, resulting in stress concentration between layers, making it prone to peeling and flaking. Furthermore, the noise reduction varies by 4-6 dB between different batches, indicating unstable performance.

[0068] In contrast, the noise reduction in Examples 1 and 5 was stable at 28-32dB, indicating that a first layer thickness of 1.0-1.2mm and a second layer thickness of 0.5-0.7mm are preferred ranges.

[0069] Then, adding a polyurea constraint layer can significantly improve the noise reduction efficiency. Specifically, the noise reduction in Examples 4 and 6 reaches 30-35 dB, which is higher than the 28-32 dB noise reduction in Example 1 without a constraint layer. Although the note in the table that the coating structure has poor stability may refer to the difficulty of construction or interface matching issues, the actual noise reduction effect is significantly improved, indicating that the constraint layer forces the damping layer to produce more intense shear deformation, which can multiply the energy dissipation efficiency.

[0070] Furthermore, the total coating thickness and drying time need to be reasonably controlled. Specifically, in Examples 2 and 3, the thickness of the first layer was increased and the drying time was extended, resulting in a decrease in interlayer bonding strength. The noise reduction amount dropped to 24-28dB and 21-25dB respectively, with limited improvement effect. This shows that simply increasing the thickness without controlling the semi-dry window will deteriorate the interlayer bonding.

[0071] Finally, Examples 5 and 6 showed consistent performance with Examples 1 and 4, verifying that the preparation method has good reproducibility and product consistency.

[0072] In summary, the semi-dry fiberglass cloth and two-layer damping coating composite process proposed in this embodiment enables the two coating layers to fuse together through the fiberglass cloth mesh, forming an interlayer synergistic damping structure. When the thickness of the first layer is 1.0–1.2 mm and the thickness of the second layer is 0.5–0.7 mm, and the fiberglass cloth is laid and the second layer is applied when the first layer is in a semi-dry state (not sticky to the touch, slightly soft to the touch), an average noise reduction of 28–32 dB can be achieved in the 100–2000 Hz frequency range. Further adding a polyurea constraint layer on the composite damping layer can increase the noise reduction to 30–35 dB. This method solves the problems of delamination, hollowness, and poor adhesion of traditional damping layers, while avoiding cracking and stress concentration caused by excessively thick coatings. It is suitable for scenarios with high requirements for vibration reduction, noise reduction, lightweighting, and reliability, such as vehicle-mounted gas storage tanks.

Claims

1. A gas storage tank, characterized in that, It includes a tank body and a damping coating. The damping coating is attached to the inner wall of the tank body. The damping coating includes a semi-dry first layer of damping coating, a second layer of damping coating, and fiberglass cloth. The fiberglass cloth is embedded between the first layer of damping coating and the second layer of damping coating and is fused and cured to form a solid shape.

2. The gas storage tank according to claim 1, characterized in that, The thickness of the first layer of damping coating is 1 to 1.5 mm, and the thickness of the second layer of damping coating is 0.5 to 1 mm.

3. The gas storage tank according to claim 2, characterized in that, The first layer of damping coating is a water-based damping coating.

4. The gas storage tank according to claim 2, characterized in that, The first layer of damping coating is a composite water-based damping coating formed by water-based acrylic copolymer emulsion, flake mica powder and / or hollow glass microspheres.

5. The gas storage tank according to any one of claims 1 to 4, characterized in that, It also includes a constraint layer, which is attached to the damping coating.

6. The gas storage tank according to claim 5, characterized in that, The constraint layer is a polyurea coating.

7. A method for preparing a gas storage tank according to claim 6, characterized in that, Includes the following steps: The inner wall of the gas storage tank is coated with a first layer of damping coating with a thickness of 1 to 1.5 mm, and is in a surface-dry to semi-dry state. Fiberglass cloth is laid on the first layer of damping coating when it is in a semi-dry state. The first layer of damping coating is applied to the fiberglass cloth in a semi-dry state, and the second layer of damping coating is sprayed or scraped on, with a thickness of 0.5 to 1 mm. The first layer of damping coating, fiberglass cloth, and the second layer of damping coating are cured to form a composite damping layer.

8. The preparation method according to claim 7, characterized in that, When semi-dry, the first layer of damping coating is not sticky to the touch and remains slightly soft when pressed.

9. The preparation method according to claim 7, characterized in that, The specific state from surface dry to semi-dry is as follows: The first layer of damping coating is a composite water-based damping coating formed by water-based acrylic copolymer emulsion, flake mica powder and / or hollow glass microspheres. After applying the first layer of damping coating at room temperature of 25°C, wait 30 to 60 minutes.

10. The preparation method according to claim 7, characterized in that, It also includes the following steps: A constraint layer is sprayed onto the composite damping layer.

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