Weldable high-damping glue and application thereof

Abstract

The invention discloses weldable high-damping glue and application thereof.The weldable high-damping glue is prepared from, by weight, 100 parts of damping rubber, 50 parts of bisphenol A epoxy resin, 30-150 parts of conductive damping functional filler, 5-25 parts of latent curing agent, 10-40 parts of flexibilizer, 1-5 parts of coupling agent and 1-10 parts of thixotropic agent; the conductive damping functional filler is a hollow microsphere with a core-shell structure, the hollow microsphere with the core-shell structure is composed of a hollow polystyrene microsphere or a hollow glass microsphere on an inner layer and a metal coating on an outer layer, and an inner cavity of the hollow microsphere with the core-shell structure is filled with air. The glue can simultaneously realize structural glue with high damping vibration attenuation, strong bonding stability, reliable welding performance and excellent processing adaptability, and is applied to damping composite metal plates, and the composite metal plates can still tolerate punch forming processing after being stored for a long time, and have no risk of cracking or layering of glue layers.

Description

Technical Field

[0001] This invention relates to the field of adhesives, and more particularly to a weldable high-damping adhesive and its applications. Background Technology

[0002] Damping adhesives, as a core functional material in metal sheet lamination, reduce structural vibration and noise through energy dissipation mechanisms and have been widely used in automotive body panels, engine hoods, aerospace structural components, and building curtain walls. As industrial demands for product performance continue to rise, damping adhesives not only need excellent vibration and noise reduction effects, but also must consider structural bonding strength, environmental stability, and compatibility with subsequent processing (such as welding and stamping).

[0003] Various damping-related adhesives and composite materials have been disclosed in the prior art. For example:

[0004] CN 119775939 A discloses a lightweight vibration-damping and noise-reducing structural adhesive, which uses epoxy resin as the matrix, combined with high-damping resin, rubber and filler, and adopts a low-temperature curing system that can be cured at 130℃. It solves the problems of insufficient vibration-damping and noise reduction and bonding performance, but does not involve the optimization design of welding performance. Although the polyurethane adhesive disclosed in CN 112280453 A emphasizes bonding strength and aging resistance, its damping performance is weak and it is difficult to meet the high vibration reduction requirements. CN 109321228 A discloses a wide-temperature-range high-damping epoxy resin structural adhesive, which achieves a balance between damping and strength through polyurethane@hollow glass microsphere composite particles, but does not consider the influence of conductivity on the welding process. The damping composite steel plate disclosed in CN 110591261 A has excellent damping, bonding and flame retardant properties, but when it is stamped after long-term storage, the adhesive layer is prone to cracking or delamination, and its welding compatibility is not clear.

[0005] Furthermore, some existing damping adhesives have performance limitations: while using ordinary conductive fillers (such as conductive silver powder) can meet the welding conductivity requirements, it leads to a significant decrease in damping performance; a single damping rubber component cannot simultaneously achieve both damping effect and adhesive toughness, affecting the long-term stability of the composite plate. Therefore, developing a structural adhesive that can simultaneously achieve high damping vibration reduction, strong adhesive stability, reliable welding performance, and excellent processing adaptability, as well as a corresponding composite metal plate, has become an urgent technical problem to be solved in this field. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a weldable high-damping adhesive. Through the synergistic design of components, it achieves an organic unity of high damping loss factor, excellent bonding strength and environmental stability, and reliable conductive welding performance. When this weldable high-damping adhesive is applied to a damping composite metal plate, the composite metal plate can still withstand stamping and forming processes after long-term storage without the risk of adhesive layer cracking or delamination.

[0007] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: Firstly, this invention provides a weldable high-damping adhesive, comprising the following raw materials by weight: 100 parts damping rubber, 50 parts bisphenol A type epoxy resin, 30-150 parts conductive damping functional filler, 5-25 parts latent curing agent, 10-40 parts toughening agent, 1-5 parts coupling agent, and 1-10 parts thixotropic agent; the conductive damping functional filler is a core-shell hollow microsphere, which is composed of an inner layer of hollow polystyrene microspheres or hollow glass microspheres and an outer layer of metal coating, wherein the inner cavity of the hollow polystyrene microspheres or hollow glass microspheres is filled with air.

[0008] Further, the core-shell hollow microspheres have a particle size of 50-1000 nm, the hollow polystyrene microspheres and hollow glass microspheres have a thickness of 30-50 nm, and the metal coating has a thickness of 10-50 nm. Preferably, the core-shell hollow microspheres have a particle size of 200-800 nm, more preferably 500-600 nm; preferably, the metal coating has a thickness of 20-40 nm, more preferably 30 nm.

[0009] Furthermore, the metal plating layer is a gold plating layer or a silver plating layer.

[0010] Furthermore, the damping rubber is at least one of nitrile rubber, solution-polymerized styrene-butadiene rubber, butyl rubber, and brominated butyl rubber.

[0011] Furthermore, the latent curing agent is at least one of dicyandiamide, adipic acid dihydrazide, modified amine microcapsule curing agent, and imidazole latent accelerator.

[0012] Furthermore, the toughening agent is at least one of carboxyl-terminated nitrile butadiene rubber, polyurethane-modified epoxy resin, thermoplastic polyamide particles, and styrene-butadiene core-shell rubber particles.

[0013] Furthermore, the coupling agent is at least one of KH-550, KH-560, and KH-792; the thixotropic agent is at least one of fumed silica, organobentonite, and polyamide wax.

[0014] Furthermore, the weldable high-damping adhesive also includes a solvent, which is at least one of ethyl acetate, methylcyclohexane, methyl ethyl ketone, and methyl isobutyl ketone, and the solid content of the weldable high-damping adhesive is 25-35%.

[0015] Secondly, the present invention provides a method for preparing the above-mentioned weldable high-damping adhesive, comprising the following steps: Preheat the internal mixer to 100-120℃, add 100 parts of damping rubber and mix for 5-10 minutes; Add 50 parts of bisphenol A type epoxy resin and 30-150 parts of electrical conductivity damping functional filler to a mixer in batches, mixing for 4-6 minutes each time; Add 5-25 parts of latent curing agent, 10-40 parts of toughening agent, 1-5 parts of coupling agent, 1-10 parts of thixotropic agent and appropriate amount of solvent, stir at room temperature for 20-26 hours to obtain a weldable high-damping adhesive.

[0016] Thirdly, the present invention also provides the application of a weldable high-damping adhesive in a damping composite metal plate, wherein the damping composite metal plate comprises at least two metal plates and a damping constraint layer located between the metal plates, and the damping constraint layer is formed by curing the aforementioned weldable high-damping adhesive.

[0017] Furthermore, the application includes the following steps: S1. The surfaces to be bonded of at least two metal plates are sequentially cleaned, degreased, and roughened. The roughening treatment is sandblasting or phosphating. After the treatment, the surface roughness Ra of the metal plates is 1.5-3.0 μm. S2. Apply the weldable high-damping adhesive to the treated surface of at least one metal plate to form an adhesive layer with a thickness of 0.05-1.0 mm; S3. Align and attach another metal plate, apply pressure of 0.1-1.5MPa, hold the pressure for 5-10 minutes to remove air bubbles, then heat at 120-180℃ for 10-60 minutes, and then cure at 80-100℃ for 24 hours to obtain a damping composite metal plate.

[0018] The beneficial effects of this invention are: This invention employs a core-shell structure conductive damping filler, in which the inner polystyrene layer and the air cavity form a highly efficient damping system, and the outer metal plating layer ensures the conductive path, resulting in a structural adhesive loss factor ≥0.097. At the same time, the laser welding and argon arc welding performance reach excellent levels, thus solving the contradiction between damping performance and welding performance in the prior art. The present invention uses bisphenol A type epoxy resin to provide a strong structural adhesive base, coupling agent to enhance interfacial bonding force, and toughening agent to improve the toughness of the adhesive layer, so that the composite metal plate maintains high peel strength in complex environments such as room temperature, high temperature and high humidity, thermal shock, and high temperature storage, and its environmental adaptability is significantly better than that of existing products. Through the synergistic design of curing process and aging treatment, as well as the control of component toughness, this invention enables composite metal plates to withstand stamping and forming processes even after long-term storage (≥3 months) without the risk of adhesive layer cracking or delamination, thus meeting the storage and subsequent processing requirements in industrial production. Detailed Implementation

[0019] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0020] Unless otherwise specified, all reagents or instruments used in this invention are commercially available products.

[0021] Example 1 Materials prepared by weight: 100 parts nitrile rubber, 50 parts bisphenol A type epoxy resin, 30 parts conductive damping functional filler (D50 particle size 500nm, hollow polystyrene microsphere thickness 40nm, outer gold plating thickness 30nm), 15 parts dicyandiamide, 20 parts polyurethane modified epoxy resin, 2 parts KH-560, 2 parts fumed silica, and the solvent is a mixture of ethyl acetate and methylcyclohexane (volume ratio 10:1).

[0022] Preparation method of weldable high-damping adhesive: Preheat the internal mixer to 110°C, add 100 parts of nitrile rubber, and mix for 8 minutes to soften it; then add 50 parts of bisphenol A epoxy resin and 30 parts of conductive damping functional filler to the internal mixer in 5 portions, mixing for 5 minutes each time; Take out the intensively mixed mixture and mix it with 15 parts dicyandiamide, 20 parts polyurethane modified epoxy resin, 2 parts KH-560 and 2 parts fumed silica at room temperature. During the mixing process, add a mixed solvent of ethyl acetate and methylcyclohexane (volume ratio 10:1) and adjust the amount of solvent added to 30% solid content. Stir at room temperature for 24 hours to obtain a weldable high-damping adhesive.

[0023] Method for preparing damping composite metal plates: S1. Surface treatment: Select two aluminum metal plates (thickness 1.0mm) and perform ultrasonic alkaline cleaning (50℃, 15 minutes), acetone degreasing, and sandblasting treatment in sequence (abrasive particle size 100 mesh, air pressure 0.5MPa, treatment time 45 seconds). The surface roughness Ra after treatment is 2.0μm. S2. Applying adhesive: At 23°C and 55% relative humidity, apply the above-mentioned weldable high-damping adhesive using a scraper, with an adhesive layer thickness of 400μm; S3. Lamination: Align and bond the two metal plates together, apply a pressure of 0.6MPa using a flatbed hot press, and hold the pressure for 8 minutes; S4. Curing: Heat at 150℃ for 30 minutes to cure, then cure at 80℃ for 24 hours to obtain a damping composite metal plate.

[0024] Example 2 Materials prepared by weight: 35 parts butyl rubber, 65 parts nitrile rubber, 50 parts bisphenol A type epoxy resin, 30 parts conductive damping functional filler (D50 particle size 500nm, hollow polystyrene microsphere thickness 40nm, outer gold plating thickness 30nm), 15 parts dicyandiamide, 20 parts polyurethane modified epoxy resin, 2 parts KH-560, 2 parts fumed silica, and the solvent is a mixed solvent of ethyl acetate and methylcyclohexane (volume ratio 10:1).

[0025] Preparation method of weldable high-damping adhesive: Preheat the internal mixer to 110°C, add 35 parts butyl rubber and 65 parts nitrile rubber, and mix for 8 minutes to soften them; then add 50 parts bisphenol A epoxy resin and 30 parts conductive damping functional filler to the internal mixer in 5 portions, mixing for 5 minutes each time. Take out the intensively mixed mixture and mix it with 15 parts dicyandiamide, 20 parts polyurethane modified epoxy resin, 2 parts KH-560 and 2 parts fumed silica at room temperature. During the mixing process, add a mixed solvent of ethyl acetate and methylcyclohexane (volume ratio 10:1) and adjust the amount of solvent added to 30% solid content. Stir at room temperature for 24 hours to obtain a weldable high-damping adhesive.

[0026] The preparation method of the damping composite metal plate is the same as that in Example 1.

[0027] Example 3 Materials prepared by weight: 35 parts butyl rubber, 65 parts nitrile rubber, 50 parts bisphenol A type epoxy resin, 30 parts conductive damping functional filler (D50 particle size 800nm, hollow polystyrene microsphere thickness 40nm, outer gold plating thickness 30nm), 15 parts dicyandiamide, 20 parts polyurethane modified epoxy resin, 2 parts KH-560, 2 parts fumed silica, and the solvent is a mixture of ethyl acetate and methylcyclohexane (volume ratio 10:1).

[0028] The preparation method of the weldable high-damping adhesive is the same as in Example 2.

[0029] The preparation method of the damping composite metal plate is the same as that in Example 1.

[0030] Example 4 Materials prepared by weight: 35 parts butyl rubber, 65 parts nitrile rubber, 50 parts bisphenol A type epoxy resin, 30 parts conductive damping functional filler (D50 particle size 200nm, hollow polystyrene microsphere thickness 40nm, outer gold plating thickness 30nm), 15 parts dicyandiamide, 20 parts polyurethane modified epoxy resin, 2 parts KH-560, 2 parts fumed silica, and the solvent is a mixed solvent of ethyl acetate and methylcyclohexane (volume ratio 10:1).

[0031] The preparation method of the weldable high-damping adhesive is the same as in Example 2.

[0032] The preparation method of the damping composite metal plate is the same as that in Example 1.

[0033] Example 5 Materials prepared by weight: 35 parts butyl rubber, 65 parts nitrile rubber, 50 parts bisphenol A type epoxy resin, 30 parts conductive damping functional filler (D50 particle size 200nm, hollow polystyrene microsphere thickness 40nm, outer silver plating thickness 30nm), 15 parts dicyandiamide, 20 parts polyurethane modified epoxy resin, 2 parts KH-560, 2 parts fumed silica, and the solvent is a mixed solvent of ethyl acetate and methylcyclohexane (volume ratio 10:1).

[0034] The preparation method of the weldable high-damping adhesive is the same as in Example 2.

[0035] The preparation method of the damping composite metal plate is the same as that in Example 1.

[0036] Example 6 Materials prepared by weight: 35 parts butyl rubber, 65 parts nitrile rubber, 50 parts bisphenol A type epoxy resin, 30 parts conductive damping functional filler (D50 particle size 200nm, hollow polystyrene microsphere thickness 40nm, outer silver plating thickness 30nm), 15 parts dicyandiamide, 25 parts styrene-butadiene core-shell rubber particles, 2 parts KH-560, 2 parts fumed silica, and the solvent is a mixed solvent of ethyl acetate and methylcyclohexane (volume ratio 10:1).

[0037] Preparation method of weldable high-damping adhesive: Preheat the internal mixer to 110°C, add 35 parts butyl rubber and 65 parts nitrile rubber, and mix for 8 minutes to soften them; then add 50 parts bisphenol A epoxy resin and 30 parts conductive damping functional filler to the internal mixer in 5 portions, mixing for 5 minutes each time. Take out the intensively mixed mixture and mix it with 15 parts dicyandiamide, 25 parts styrene-butadiene core-shell rubber particles, 2 parts KH-560 and 2 parts fumed silica at room temperature. During the mixing process, add a mixed solvent of ethyl acetate and methylcyclohexane (volume ratio 10:1) and adjust the amount of solvent added to a solid content of 30%. Stir at room temperature for 24 hours to obtain a weldable high-damping adhesive.

[0038] The preparation method of the damping composite metal plate is the same as that in Example 1.

[0039] Example 7 Materials prepared by weight: 35 parts butyl rubber, 65 parts nitrile rubber, 50 parts bisphenol A type epoxy resin, 30 parts conductive damping functional filler (D50 particle size 200nm, hollow polystyrene microsphere thickness 40nm, outer silver plating thickness 30nm), 10 parts adipic acid dihydrazide, 25 parts styrene-butadiene core-shell rubber particles, 2 parts KH-560, 2 parts fumed silica, and the solvent is a mixture of ethyl acetate and methylcyclohexane (volume ratio 10:1).

[0040] Preparation method of weldable high-damping adhesive: Preheat the internal mixer to 110°C, add 35 parts butyl rubber and 65 parts nitrile rubber, and mix for 8 minutes to soften them; then add 50 parts bisphenol A epoxy resin and 30 parts conductive damping functional filler to the internal mixer in 5 portions, mixing for 5 minutes each time. Take out the intensively mixed mixture and mix it with 10 parts of adipic acid dihydrazide, 25 parts of styrene-butadiene core-shell rubber particles, 2 parts of KH-560 and 2 parts of fumed silica at room temperature. During the mixing process, add a mixed solvent of ethyl acetate and methylcyclohexane (volume ratio 10:1) and adjust the amount of solvent added to 30% of the solid content. Stir at room temperature for 24 hours to obtain a weldable high-damping adhesive.

[0041] The preparation method of the damping composite metal plate is the same as that in Example 1.

[0042] Example 8 Materials prepared by weight: 35 parts butyl rubber, 65 parts nitrile rubber, 50 parts bisphenol A type epoxy resin, 30 parts conductive damping functional filler (D50 particle size 200nm, hollow glass microsphere thickness 40nm, outer silver plating thickness 30nm), 10 parts adipic acid dihydrazide, 25 parts styrene-butadiene core-shell rubber particles, 1.5 parts KH-550, 2 parts fumed silica, and the solvent is a mixture of ethyl acetate and methylcyclohexane (volume ratio 10:1).

[0043] Preparation method of weldable high-damping adhesive: Preheat the internal mixer to 110°C, add 35 parts butyl rubber and 65 parts nitrile rubber, and mix for 8 minutes to soften them; then add 50 parts bisphenol A epoxy resin and 30 parts conductive damping functional filler to the internal mixer in 5 portions, mixing for 5 minutes each time. The intensively mixed mixture was taken out and mixed with 10 parts of adipic acid dihydrazide, 25 parts of styrene-butadiene core-shell rubber particles, 1.5 parts of KH-550 and 2 parts of fumed silica at room temperature. During the mixing process, a mixed solvent of ethyl acetate and methylcyclohexane (volume ratio 10:1) was added to adjust the amount of solvent added to 30% of the solid content. The mixture was stirred at room temperature for 24 hours to obtain a weldable high-damping adhesive.

[0044] The preparation method of the damping composite metal plate is the same as that in Example 1.

[0045] Comparative Example 1 Materials prepared by weight: 35 parts butyl rubber, 65 parts nitrile rubber, 50 parts bisphenol A type epoxy resin, 30 parts conductive silver powder (D50 particle size 500nm), 15 parts dicyandiamide, 20 parts polyurethane modified epoxy resin, 2 parts KH-560, 2 parts fumed silica, and the solvent is a mixture of ethyl acetate and methylcyclohexane (volume ratio 10:1).

[0046] Preparation method of structural adhesive: Preheat the internal mixer to 110°C, add 35 parts butyl rubber and 65 parts nitrile rubber, and mix for 8 minutes to soften them; then add 50 parts bisphenol A epoxy resin and 30 parts conductive silver powder to the internal mixer in 5 portions, mixing for 5 minutes each time. Take out the intensively mixed mixture and mix it with 15 parts dicyandiamide, 20 parts polyurethane modified epoxy resin, 2 parts KH-560 and 2 parts fumed silica at room temperature. During the mixing process, add a mixed solvent of ethyl acetate and methylcyclohexane (volume ratio 10:1) and adjust the amount of solvent added to 30% solid content. Stir at room temperature for 24 hours to obtain a weldable high-damping adhesive.

[0047] The preparation method of the damping composite metal plate is the same as that in Example 1.

[0048] Comparative Example 2 Materials prepared by weight: 100 parts butyl rubber, 50 parts bisphenol A type epoxy resin, 30 parts conductive damping functional filler (D50 particle size 500nm, hollow polystyrene microsphere thickness 40nm, outer silver plating thickness 30nm), 15 parts dicyandiamide, 20 parts polyurethane modified epoxy resin, 2 parts KH-560, 2 parts fumed silica, solvent is a mixed solvent of ethyl acetate and methylcyclohexane (volume ratio 10:1), adjust the solid content to 30%.

[0049] Preparation method of structural adhesive: Preheat the internal mixer to 110°C, add 100 parts of butyl rubber, and mix for 8 minutes to soften it; then add 50 parts of bisphenol A epoxy resin and 30 parts of conductive damping functional filler to the internal mixer in 5 portions, mixing for 5 minutes each time; Take out the intensively mixed mixture and mix it with 15 parts dicyandiamide, 20 parts polyurethane modified epoxy resin, 2 parts KH-560 and 2 parts fumed silica at room temperature. During the mixing process, add a mixed solvent of ethyl acetate and methylcyclohexane (volume ratio 10:1) and adjust the amount of solvent added to 30% solid content. Stir at room temperature for 24 hours to obtain a weldable high-damping adhesive.

[0050] The preparation method of the damping composite metal plate is the same as that in Example 1.

[0051] Comparative Example 3 A structural adhesive with the same composition as in Example 1.

[0052] The preparation method of the structural adhesive is the same as that in Example 1.

[0053] Preparation method of damping composite metal plate: Steps S1-S3 are the same as in Example 1. In step S4, the plate is cured by heating at 150°C for 30 minutes. The curing treatment is cancelled to obtain the damping composite metal plate.

[0054] Performance testing The performance of the damping composite metal plates prepared in Examples 1-9 and Comparative Examples 1-3 was tested according to the relevant industry testing standards of national standards GB / T 14683-2017, GB / T 2794-2013, and GB / T18258-2000. The results are shown in Table 1 below. In comparison, we aim to ① protect the use of hollow microspheres, whether glass, polyethylene, or polystyrene, through surface electroplating. This not only achieves the goal of improving conductivity to make weldable composite metal plates possible, solving the application problem of weldable composite metal plates in this field, but also, through the design of the core / shell and conductive layer of the hollow microspheres, achieves the damping characteristics of the composite metal plate. Furthermore, by introducing gold / silver-plated microspheres, due to the chemical inertness of these precious metals, ③ the composite steel plate exhibits superior environmental resistance after environmental reliability tests (high temperature and humidity, temperature shock, high temperature storage, etc.) compared to materials introduced by other techniques in this field. This patent embodies the "three properties" of the patent based on the above three points. Table 1

[0055] Test results show that the damping composite metal plates prepared in Examples 1-8 of this invention all possess high loss factors (≥>0.0971), excellent bonding strength and environmental stability, good laser welding and argon arc welding performance, and no cracking or delamination after stamping processing after 3 months of storage; while Comparative Example 1, due to the use of ordinary conductive silver powder, showed a significant decrease in damping performance (loss factor only 0.046); Comparative Example 2, due to the use of a single butyl rubber as the damping component, had extremely poor bonding strength and environmental stability, and local cracking occurred during stamping after storage; Comparative Example 3, due to the omission of curing treatment, had insufficient cross-linking density of the adhesive layer, resulting in a significant decrease in bonding strength and severe delamination.

[0056] This invention utilizes hollow microspheres with a surface electroplating layer. This not only achieves the goal of weldable composite metal plates by improving conductivity, solving the application problem of weldable composite metal plates in this field, but also achieves the damping characteristics of composite metal plates through the design of the core / shell and conductive layer of the hollow microspheres. Furthermore, by introducing gold / silver coated microspheres, the composite steel plate exhibits superior environmental resistance after environmental reliability tests (high temperature and humidity, temperature shock, high temperature storage, etc.) due to the chemical inertness of these precious metals.

[0057] Based on the disclosure in the foregoing specification, those skilled in the art can make appropriate changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on the present invention.

Claims

1. A weldable high-damping adhesive, characterized in that: The raw materials, by weight, include the following components: 100 parts damping rubber, 50 parts bisphenol A type epoxy resin, 30-150 parts conductive damping functional filler, 5-25 parts latent curing agent, 10-40 parts toughening agent, 1-5 parts coupling agent, and 1-10 parts thixotropic agent; the conductive damping functional filler is a core-shell hollow microsphere, which is composed of an inner layer of hollow polystyrene microspheres or hollow glass microspheres and an outer layer of metal coating, wherein the inner cavity of the hollow polystyrene microspheres and hollow glass microspheres is filled with air.

2. The weldable high-damping adhesive according to claim 1, characterized in that: The core-shell hollow microspheres have a particle size of 50-1000 nm, the hollow polystyrene microspheres and hollow glass microspheres have a thickness of 30-50 nm, and the metal coating has a thickness of 10-50 nm.

3. The weldable high-damping adhesive according to claim 1, characterized in that: The metal plating layer is a gold plating layer or a silver plating layer.

4. The weldable high-damping adhesive according to claim 1, characterized in that: The damping rubber is at least one of nitrile rubber, solution-polymerized styrene-butadiene rubber, butyl rubber, and brominated butyl rubber.

5. The weldable high-damping adhesive according to claim 1, characterized in that: The latent curing agent is at least one of dicyandiamide, adipic acid dihydrazide, modified amine microcapsule curing agent, and imidazole latent accelerator.

6. The weldable high-damping adhesive according to claim 1, characterized in that: The toughening agent is at least one of carboxyl-terminated nitrile butadiene rubber, polyurethane-modified epoxy resin, thermoplastic polyamide particles, and styrene-butadiene core-shell rubber particles.

7. The weldable high-damping adhesive according to claim 1, characterized in that: The coupling agent is at least one of KH-550, KH-560, and KH-792; the thixotropic agent is at least one of fumed silica, organobentonite, and polyamide wax.

8. The weldable high-damping adhesive according to claim 1, characterized in that: It also includes a solvent, which is at least one of ethyl acetate, methylcyclohexane, methyl ethyl ketone, and methyl isobutyl ketone, and the solid content of the weldable high-damping adhesive is 25-35%.

9. An application of a weldable high-damping adhesive, characterized in that: Its application is in damping composite metal plates, which include at least two metal plates and a damping constraint layer located between the metal plates. The damping constraint layer is formed by curing the weldable high-damping adhesive as described in any one of claims 1-8.

10. The application of the weldable high-damping adhesive according to claim 9, characterized in that: The application includes the following steps: S1. The surfaces to be bonded of at least two metal plates are sequentially cleaned, degreased, and roughened. The roughening treatment is sandblasting or phosphating. After the treatment, the surface roughness Ra of the metal plates is 1.5-3.0 μm. S2. Apply the weldable high-damping adhesive to the treated surface of at least one metal plate to form an adhesive layer with a thickness of 0.05-1.0 mm; S3. Align and attach another metal plate, apply pressure of 0.1-1.5MPa, hold the pressure for 5-10 minutes to remove air bubbles, then heat at 120-180℃ for 10-60 minutes, and then cure at 80-100℃ for 24 hours to obtain a damping composite metal plate.

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