A composite coating material, its preparation and use

Abstract

The present application relates to the technical field of functional composite materials, in particular to a composite coating material and a preparation method and application thereof. The composite coating material is composed of an anticorrosion reinforcing layer, a composite sound-absorbing layer and a weather-resistant layer which are stacked and combined in sequence. The present application integrates the three functions of anticorrosion, sound absorption and weather resistance into an integrated coating system, and through the precise design and synergistic effect of each functional layer, excellent adhesion and anticorrosion, high-efficiency wide-band sound-absorbing capacity and good weather protection are simultaneously realized in a single coating system. In addition, the preparation method of the present application has clear steps, adopts conventional coating and curing processes, and the curing conditions of each layer are mild and controllable. The whole process does not require complex assembly or filling steps, and is suitable for implementation on a metal plate continuous production line, which is conducive to large-scale popularization and application.

Description

Technical Field

[0001] This invention relates to the field of functional composite materials technology, and in particular to a composite coating material, its preparation method, and its application. Background Technology

[0002] Metal building panels such as corrugated steel sheets and steel truss floor decking are widely used due to their high strength and ease of construction, but their noise control capabilities are generally weak. Currently, to improve the sound absorption performance of these metal panels, a common construction method is "perforated metal sheet + porous sound-absorbing material (such as glass wool or rock wool) filling the back cavity." However, this method has several significant drawbacks: 1) The structure is complex, significantly increasing the system's self-weight; 2) The sound-absorbing material is prone to settling or moisture absorption, leading to performance degradation or even failure; 3) The bonding force between the porous material and the metal sheet is weak, affecting the overall structural strength and durability; 4) The anti-corrosion coating of traditional corrugated steel sheets (such as polyester paint) mainly serves decorative and basic rust prevention functions, with limited adhesion to the substrate, weather resistance, and enhancement of overall structural performance.

[0003] Therefore, there is an urgent need to develop an integrated functional material that can firmly bond with metal substrates, integrate long-term active corrosion protection, high-efficiency broadband sound absorption, and good workability, and this material should be easy to apply to the surface of metal sheets. Summary of the Invention

[0004] The purpose of this invention is to address the problems existing in the prior art by providing a composite coating material, its preparation method, and its application. By providing a composite coating material consisting of a corrosion-resistant reinforcing layer, a composite sound-absorbing layer, and a weather-resistant layer stacked and combined in sequence, the technical problems existing in the noise control, long-term corrosion protection, structural strength, and durability of existing metal sheets are effectively solved.

[0005] To achieve the above objectives, the present invention provides a composite coating material, which is composed of a corrosion-resistant reinforcing layer, a composite sound-absorbing layer and a weather-resistant layer that are stacked and combined in sequence; The anti-corrosion reinforcement layer comprises the following raw materials in parts by weight: 30-50 parts epoxy modified acrylic resin emulsion, 10-25 parts silica sol, 5-15 parts flake zinc powder, 3-10 parts mica powder, 0.5-2 parts silane coupling agent, 0.3-1 part wetting and dispersing agent, 3-8 parts water-based curing agent, and 15-40 parts water; The composite sound-absorbing layer comprises the following raw materials in parts by weight: 20-40 parts of waterborne polyurethane dispersion, 25-45 parts of damping filler, 30-50 parts of porous sound-absorbing aggregate, 0.5-3 parts of chemical foaming agent, 0.1-0.5 parts of foam stabilizer, and 10-25 parts of water.

[0006] Preferably, the damping filler is selected from one or more of rubber powder, vermiculite, and closed-cell ceramic microspheres; the porous sound-absorbing aggregate is selected from one or more of expanded perlite, foamed ceramic particles, and porous inorganic fiber cotton blocks.

[0007] Preferably, the composite sound-absorbing layer has a pore size gradient distribution, wherein the average pore size on the side closer to the anti-corrosion reinforcement layer is smaller than the average pore size on the side farther from the anti-corrosion reinforcement layer.

[0008] Preferably, the weather-resistant layer is a fluorocarbon coating layer or a polyvinylidene fluoride coating layer.

[0009] Preferably, the thickness ratio of the anti-corrosion reinforcement layer, the composite sound-absorbing layer, and the weather-resistant layer is 10-50μm: 1-5mm: 15-40μm.

[0010] The present invention also provides a method for preparing the composite coating material, comprising the following steps: S1. Apply the anti-corrosion reinforcement slurry to the surface of the substrate and cure it to form a semi-cured layer; S2. The composite sound-absorbing layer slurry is coated on the surface of the semi-cured layer and cured to form a composite sound-absorbing layer that is bonded to the anti-corrosion reinforcement layer; S3. Apply the weather-resistant coating to the surface of the composite sound-absorbing layer and cure it to form a weather-resistant layer.

[0011] Preferably, the curing conditions in S1 are: curing at 80-120℃ for 5-15 minutes; the curing conditions in S2 are: curing at 100-140℃ for 20-40 minutes; and the curing conditions in S3 are: curing at 80-120℃ for 10-20 minutes.

[0012] The present invention also provides the application of the aforementioned composite coating material in composite metal plates.

[0013] The present invention also provides a composite metal plate, comprising a metal substrate and the aforementioned composite coating material.

[0014] Preferably, the metal substrate is selected from galvanized steel sheet, galvanized aluminum steel sheet or aluminum alloy sheet.

[0015] The beneficial effects of this invention are as follows: 1. This invention provides a composite coating material, consisting of a corrosion-resistant reinforcing layer, a composite sound-absorbing layer, and a weather-resistant layer stacked and combined sequentially. This invention integrates corrosion resistance, sound absorption, and weather resistance into a single coating system. Through the precise design and synergistic effect of each functional layer, excellent adhesion and corrosion resistance, efficient broadband sound absorption, and good weather protection are simultaneously achieved in a single coating system. Compared to the complex structure of traditional "perforated plate + back cavity filling," this invention greatly simplifies the structure, facilitates construction, and avoids problems such as significantly increased self-weight, easy settling and moisture absorption of the sound-absorbing material, and weak bonding with the substrate caused by complex construction.

[0016] 2. In the anti-corrosion reinforcement layer, the epoxy-modified acrylic resin emulsion provides a good film-forming and adhesion foundation; the silica sol enhances the density and hardness of the coating; the flake zinc powder provides long-lasting active anti-corrosion protection; the mica powder further enhances the coating's impermeability and mechanical strength; the addition of silane coupling agent and wetting and dispersing agent significantly improves the compatibility between the components and the interfacial bonding force between the coating and the metal substrate.

[0017] 3. In the composite sound-absorbing layer, the waterborne polyurethane dispersion imparts good flexibility and bonding strength to the coating; the damping filler consumes sound energy through internal friction; the porous sound-absorbing aggregate provides the main sound wave dissipation structure; the chemical foaming agent decomposes during the curing process to generate bubbles, which together with the inherent pores of the aggregate form a complex porous network, greatly increasing the sound wave propagation path and energy loss.

[0018] 4. This invention, by controlling the formulation and curing process of the composite sound-absorbing layer slurry, enables the cured sound-absorbing layer to form a gradient porous structure with a smaller average pore size near the anti-corrosion reinforcement layer and a larger average pore size away from it. This gradient structure facilitates continuous matching of acoustic impedance along the coating thickness direction, reduces sound wave reflection at the interface, promotes the penetration and efficient dissipation of sound waves into the coating, and thus achieves wider-bandwidth, high-efficiency sound absorption with a thinner thickness.

[0019] 5. The outermost fluorocarbon coating or polyvinylidene fluoride coating layer has excellent UV resistance, chemical corrosion resistance, pollution resistance and self-cleaning properties, which can effectively protect the inner sound-absorbing layer and anti-corrosion reinforcement layer from external environmental factors and ensure the performance stability of the entire coating system under long-term outdoor use.

[0020] 6. The preparation method of this invention has clear steps, employing conventional coating and curing processes, with mild and controllable curing conditions for each layer. In particular, by coating the semi-cured anti-corrosion reinforcing layer with a composite sound-absorbing slurry, chemical bonding and physical anchoring between the two layers are achieved, ensuring interlayer adhesion. The entire process requires no complex assembly or filling steps, making it suitable for implementation on continuous metal sheet production lines and facilitating large-scale application.

[0021] 7. The metal plates (such as galvanized steel plates, galvanized aluminum steel plates, and aluminum alloy plates) of the composite coating material of the present invention, while maintaining the original advantages of high strength, light weight, and convenient construction of the metal substrate, integrate excellent sound absorption and noise reduction, long-term corrosion resistance and weather resistance. They can be widely used in building envelopes, industrial plants, transportation facilities and other fields with high requirements for acoustic environment and durability. Detailed Implementation

[0022] This invention provides a composite coating material, which is composed of a corrosion-resistant reinforcing layer, a composite sound-absorbing layer and a weather-resistant layer stacked and combined in sequence; The anti-corrosion reinforcement layer comprises the following raw materials in parts by weight: 30-50 parts epoxy modified acrylic resin emulsion, 10-25 parts silica sol, 5-15 parts flake zinc powder, 3-10 parts mica powder, 0.5-2 parts silane coupling agent, 0.3-1 part wetting and dispersing agent, 3-8 parts water-based curing agent, and 15-40 parts water; The composite sound-absorbing layer comprises the following raw materials in parts by weight: 20-40 parts of waterborne polyurethane dispersion, 25-45 parts of damping filler, 30-50 parts of porous sound-absorbing aggregate, 0.5-3 parts of chemical foaming agent, 0.1-0.5 parts of foam stabilizer, and 10-25 parts of water.

[0023] In this invention, the epoxy-modified acrylic resin emulsion has a solid content of 45-55%; the silica sol has a solid content of 20-30%; the zinc flakes have a diameter of 10-50 μm; the mica powder has a particle size of 600-1000 mesh; the silane coupling agent is selected from KH-560; the wetting and dispersing agent is selected from BYK-190; and the waterborne curing agent is selected from waterborne polyamide curing agents.

[0024] In this invention, the solid content of the aqueous polyurethane dispersion is 35-45%; the chemical foaming agent is selected from ammonium bicarbonate or azodicarbonamide; and the foam stabilizer is selected from sodium dodecyl sulfate.

[0025] In this invention, the damping filler is selected from one or more of rubber powder, vermiculite, and closed-cell ceramic microspheres; the particle size of the damping filler is 50-300 mesh; the porous sound-absorbing aggregate is selected from one or more of expanded perlite, foamed ceramic particles, and porous inorganic fiber cotton blocks; the particle size of the porous sound-absorbing aggregate is 0.5-3 mm.

[0026] In this invention, the composite sound-absorbing layer has a pore size gradient distribution, wherein the average pore size on the side closer to the anti-corrosion reinforcement layer is smaller than the average pore size on the side farther from the anti-corrosion reinforcement layer.

[0027] In this invention, the weather-resistant layer is a fluorocarbon coating layer or a polyvinylidene fluoride coating layer.

[0028] In this invention, the thickness ratio of the anti-corrosion reinforcement layer, the composite sound-absorbing layer, and the weather-resistant layer is 10-50μm: 1-5mm: 15-40μm.

[0029] The present invention also provides a method for preparing the composite coating material, comprising the following steps: S1. Apply the anti-corrosion reinforcement slurry to the surface of the substrate and cure it to form a semi-cured layer; S2. The composite sound-absorbing layer slurry is coated on the surface of the semi-cured layer and cured to form a composite sound-absorbing layer that is bonded to the anti-corrosion reinforcement layer; S3. Apply the weather-resistant coating to the surface of the composite sound-absorbing layer and cure it to form a weather-resistant layer.

[0030] In this invention, in step S1, the preparation process of the anti-corrosion reinforcing layer slurry includes: mixing water, wetting and dispersing agent, silane coupling agent, silica sol, flake zinc powder and mica powder, dispersing them evenly at 800-1500 rpm, then adding epoxy modified acrylic resin emulsion and stirring evenly at 200-400 rpm, and finally adding water-based curing agent to adjust the viscosity of the system to 30-50 s at Fort-4 cup to obtain the anti-corrosion reinforcing layer slurry.

[0031] In this invention, in S1, the preparation process of the composite sound-absorbing layer slurry includes: mixing water, foam stabilizer, and waterborne polyurethane dispersion evenly, adding damping filler and porous sound-absorbing aggregate and stirring until a uniform paste is formed to obtain a base paste; before coating, adding a chemical foaming agent to the base paste and stirring and mixing at 1400-1600 rpm to obtain the composite sound-absorbing layer slurry.

[0032] In this invention, the curing conditions in S1 are: curing at 80-120℃ for 5-15 minutes; the curing conditions in S2 are: curing at 100-140℃ for 20-40 minutes; and the curing conditions in S3 are: curing at 80-120℃ for 10-20 minutes.

[0033] In this invention, the composite sound-absorbing layer forms a gradient pore size distribution during the curing process. The mechanism is as follows: heat is transferred upwards from the substrate side, resulting in a temperature gradient in the slurry along its thickness. The slurry layer closer to the substrate is heated first, and the foaming agent decomposes in the high-viscosity environment to form fine bubbles; while the slurry layer farther from the substrate foams later, the overall system temperature rises and viscosity decreases, and the bubbles generated in the lower layer float and merge under buoyancy, thus forming larger pores. Simultaneously, the semi-cured anti-corrosion reinforcing layer below restricts the downward development of bubbles, promoting upward bubble growth.

[0034] The gradient porous structure, with a smaller average pore size on the side closer to the anti-corrosion reinforcement layer and a larger average pore size on the side farther away, is conducive to continuous matching of acoustic impedance, thereby achieving wideband and high-efficiency sound absorption.

[0035] In this invention, after S3, the substrate containing the composite coating material is obtained by cooling and roll forming.

[0036] The present invention also provides the application of the aforementioned composite coating material in composite metal plates.

[0037] The present invention also provides a composite metal plate, comprising a metal substrate and the aforementioned composite coating material.

[0038] In this invention, the metal substrate is selected from galvanized steel plate, galvanized aluminum steel plate or aluminum alloy plate; the thickness of the metal substrate is 0.3-2mm.

[0039] The present invention will be further described below with reference to embodiments. Unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art. The features mentioned above or in the specific examples mentioned in this invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the invention and are not intended to limit the scope of the invention.

[0040] In the following embodiments and comparative examples of the present invention, the epoxy-modified acrylic resin emulsion was purchased from Zhanxin Resin (Shanghai) Co., Ltd.; the silica sol was purchased from Qingdao Ocean Chemical Co., Ltd.; the waterborne polyamide curing agent was purchased from Hansen Chemical Trading (Shanghai) Co., Ltd.; the waterborne polyurethane dispersion was purchased from Wanhua Chemical Group Co., Ltd.; the closed-cell ceramic microspheres were purchased from Jiangsu Jinlibao Adhesive Products Co., Ltd.; the foamed ceramic particles were purchased from Guangdong Jinyitao Ceramics Group Co., Ltd.; the porous inorganic fiber cotton block was purchased from Huamei Energy Saving Technology Group Co., Ltd.; the polyvinylidene fluoride coating was purchased from PMB Paint (Shanghai) Co., Ltd.; and the fluorocarbon coating was purchased from AkzoNobel Paints (China) Co., Ltd.

[0041] Example 1 This embodiment provides a composite metal plate containing a composite coating material, the preparation method of which includes the following steps: A 0.8mm thick galvanized aluminum steel sheet is subjected to alkaline degreasing, water washing, drying, and iron-based phosphating treatment in sequence to obtain a clean surface with good adhesion activity, thus obtaining a pretreated steel sheet.

[0042] Take 20 parts water, add 0.5 parts BYK-190, 1 part KH-560, 15 parts silica sol with a solid content of 25%, 10 parts flake zinc powder with a flake diameter of 30μm, and 5 parts mica powder with a particle size of 800 mesh. Disperse the mixture at a high speed of 1200 rpm for 15 min in a disperser. Then slowly add 40 parts epoxy-modified acrylic resin emulsion with a solid content of 50% and stir at a low speed of 300 rpm for 10 min. Finally, add 5 parts water-based polyamide curing agent and adjust the viscosity to 40 s (Ford Cup 4) to obtain the anti-corrosion reinforcement slurry. Roller coat the anti-corrosion reinforcement slurry onto the pretreated steel plate and cure it at 100℃ for 8 min to form a semi-cured layer.

[0043] Take 18 parts water, add 0.3 parts sodium dodecyl sulfate and 30 parts waterborne polyurethane dispersion with a solid content of 40%, and mix well. Add 20 parts rubber powder with a particle size of 100 mesh, 15 parts closed-cell ceramic microspheres with a particle size of 80 mesh, and 35 parts expanded perlite with a particle size of 1-2 mm, and stir to form a uniform paste. Just before spraying, add 2 parts ammonium bicarbonate to the paste and stir at high speed at 1500 rpm for 30 seconds to initiate foaming. Immediately use a foam sprayer to evenly spray the slurry onto the semi-cured layer, and cure at 120℃ for 30 minutes to form a composite sound-absorbing layer bonded to the anti-corrosion reinforcement layer.

[0044] Polyvinylidene fluoride coating is roller-coated onto the surface of the composite sound-absorbing layer and cured at 100°C for 15 minutes to form a weather-resistant layer.

[0045] After cooling to room temperature, the composite metal plate containing composite coating material is obtained by roll forming, wherein the thickness of the anti-corrosion reinforcement layer is 30μm, the thickness of the composite sound absorption layer is 3mm, and the thickness of the weather-resistant layer is 25μm.

[0046] Example 2 This embodiment provides a composite metal plate containing a composite coating material, the preparation method of which includes the following steps: A 1mm thick galvanized steel sheet is subjected to alkaline degreasing, water washing, drying, and iron-based phosphating treatment in sequence to obtain a clean surface with good adhesion activity, thus obtaining a pretreated steel sheet.

[0047] Take 23 parts water, add 0.8 parts BYK-190, 1.5 parts KH-560, 20 parts silica sol with a solid content of 25%, 8 parts flake zinc powder with a flake diameter of 30 μm, and 8 parts mica powder with a particle size of 800 mesh. Disperse the mixture at a high speed of 1000 rpm for 20 min in a disperser. Then slowly add 45 parts epoxy-modified acrylic resin emulsion with a solid content of 50% and stir at a low speed of 400 rpm for 8 min. Finally, add 6 parts water-based polyamide curing agent and adjust the viscosity to 45 s (Ford Cup 4) to obtain the anti-corrosion reinforcement slurry. Roll the anti-corrosion reinforcement slurry onto the pretreated steel plate and cure it at 110℃ for 10 min to form a semi-cured layer.

[0048] Take 22 parts water, add 0.4 parts sodium dodecyl sulfate and 35 parts waterborne polyurethane dispersion with a solid content of 40%, and mix well. Add 30 parts vermiculite with a particle size of 150 mesh and 40 parts foamed ceramic particles with a particle size of 1-3 mm, and stir to form a uniform paste. Just before spraying, add 1.5 parts azodicarbonamide to the paste and stir at high speed at 1400 rpm for 35 seconds to initiate foaming. Immediately use a foam sprayer to evenly spray the slurry onto the semi-cured layer, and cure at 130℃ for 25 minutes to form a composite sound-absorbing layer that bonds with the anti-corrosion reinforcement layer.

[0049] Fluorocarbon coating is roller-coated onto the surface of the composite sound-absorbing layer and cured at 110℃ for 12 minutes to form a weather-resistant layer.

[0050] After cooling to room temperature, the composite metal plate containing composite coating material is obtained by roll forming, wherein the thickness of the anti-corrosion reinforcement layer is 40μm, the thickness of the composite sound absorption layer is 4mm, and the thickness of the weather-resistant layer is 20μm.

[0051] Example 3 This embodiment provides a composite metal plate containing a composite coating material, the preparation method of which includes the following steps: A 0.5mm thick 5052 aluminum alloy plate is subjected to alkaline degreasing, water washing, drying and chromate passivation treatment in sequence to obtain a clean surface with good adhesion activity, thus obtaining a pretreated plate.

[0052] Take 15 parts water, add 0.3 parts BYK-190, 0.8 parts KH-560, 12 parts silica sol with a solid content of 25%, 6 parts flake zinc powder with a flake diameter of 30μm, and 3 parts mica powder with a particle size of 800 mesh. Disperse the mixture at a high speed of 1500 rpm for 10 min in a disperser. Then slowly add 35 parts epoxy-modified acrylic resin emulsion with a solid content of 50% and stir at a low speed of 200 rpm for 15 min. Finally, add 4 parts water-based polyamide curing agent and adjust the viscosity to 35 s (Ford Cup 4) to obtain the anti-corrosion reinforcement layer slurry. Roll the anti-corrosion reinforcement layer slurry onto the pretreated plate and cure it at 90℃ for 12 min to form a semi-cured layer.

[0053] Take 12 parts water, add 0.2 parts sodium dodecyl sulfate and 25 parts waterborne polyurethane dispersion with a solid content of 40%, and mix well. Add 12.5 parts rubber powder with a particle size of 80 mesh, 12.5 parts closed-cell ceramic microspheres with a particle size of 50 mesh, and 30 parts porous inorganic fiber cotton blocks with a particle size of 0.5-1.5 mm, and stir to form a uniform paste. Just before spraying, add 1 part ammonium bicarbonate to the paste and stir at high speed at 1600 rpm for 25 seconds to initiate foaming. Immediately use a foam sprayer to evenly spray the slurry onto the semi-cured layer, and cure at 110℃ for 35 minutes to form a composite sound-absorbing layer bonded to the anti-corrosion reinforcement layer.

[0054] Polyvinylidene fluoride coating is roller-coated onto the surface of the composite sound-absorbing layer and cured at 90°C for 18 minutes to form a weather-resistant layer.

[0055] After cooling to room temperature, the composite metal plate containing composite coating material is obtained by roll forming, wherein the thickness of the anti-corrosion reinforcement layer is 15μm, the thickness of the composite sound absorption layer is 1.5mm, and the thickness of the weather-resistant layer is 30μm.

[0056] Comparative Example 1 This comparative example provides a composite metal plate containing a composite coating material, which differs from Example 1 in that the preparation and application steps of the anti-corrosion reinforcement slurry are omitted.

[0057] Comparative Example 2 This comparative example provides a composite metal plate containing a composite coating material, which differs from Example 1 in that the addition of chemical foaming agent (ammonium bicarbonate) in the composite sound-absorbing layer is omitted.

[0058] Comparative Example 3 This comparative example uses a 0.8mm thick galvanized perforated sheet (perforation rate 20%), with a 50mm thick sound-absorbing layer behind it. This sound-absorbing layer has a density of 32kg / m³. 3 It is filled with centrifugal glass wool.

[0059] Experimental Example 1 Performance tests were conducted on the samples obtained in Examples 1-3 and Comparative Examples 1-3, and the test results are recorded in Table 1. The sound absorption performance test was conducted according to GB / T 20247-2006 "Measurement of Sound Absorption Coefficient and Acoustic Impedance in Acoustic Impedance Tubes - Part 2: Transfer Function Method," using a B&K 4206 impedance tube testing system. Before testing, the samples of each example and comparative example were cut into standard specimens with a diameter of 100mm and installed on a rigid specimen rack that met the standard requirements, ensuring that the back was a closed rigid wall. The sound absorption coefficients of the samples were measured at the center frequencies of five 1 / 3 octave bands: 250Hz, 500Hz, 1000Hz, 2000Hz, and 4000Hz, and their arithmetic mean was calculated as the average sound absorption coefficient. Adhesion testing was conducted according to GB / T... According to GB / T 1771-2007 "Determination of Neutral Salt Spray Resistance of Paints and Varnishes", the surface of the sample is scratched with a single pass (penetrating to the substrate) and then placed in a salt spray chamber for 500 hours of neutral salt spray (NSS) testing (test conditions: 5% NaCl solution, pH 6.5-7.2, chamber temperature 35℃). After the test, the sample is removed, washed and dried, and the maximum width of rust or coating peeling spreading to one side at the scratch is measured. (0 is the best, 5 is the worst) 9286-1998 "Cross-cut Test of Paints and Varnishes" is used to evaluate the adhesion level between the anti-corrosion reinforcement layer and the metal substrate (or between the composite sound-absorbing layer and the substrate in Comparative Example 1).

[0060] Table 1 Test Results

[0061] Therefore, the present invention adopts the above-mentioned composite coating material, its preparation method and application, which effectively overcomes the defects of the prior art and provides an innovative solution that integrates strong adhesion, long-lasting active corrosion protection, high-efficiency broadband sound absorption, excellent weather resistance and construction convenience.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A composite coating material, characterized in that, It consists of a corrosion-resistant reinforcement layer, a composite sound-absorbing layer, and a weather-resistant layer that are layered and combined sequentially; The anti-corrosion reinforcement layer comprises the following raw materials in parts by weight: 30-50 parts epoxy modified acrylic resin emulsion, 10-25 parts silica sol, 5-15 parts flake zinc powder, 3-10 parts mica powder, 0.5-2 parts silane coupling agent, 0.3-1 part wetting and dispersing agent, 3-8 parts water-based curing agent, and 15-40 parts water; The composite sound-absorbing layer comprises the following raw materials in parts by weight: 20-40 parts of water-based polyurethane dispersion, 25-45 parts of damping filler, 30-50 parts of porous sound-absorbing aggregate, 0.5-3 parts of chemical foaming agent, 0.1-0.5 parts of foam stabilizer, and 10-25 parts of water. The composite sound-absorbing layer has a pore size gradient distribution, wherein the average pore size on the side closer to the anti-corrosion reinforcement layer is smaller than the average pore size on the side farther away from the anti-corrosion reinforcement layer.

2. The composite coating material according to claim 1, characterized in that, The damping filler is selected from one or more of rubber powder, vermiculite, and closed-cell ceramic microspheres; the porous sound-absorbing aggregate is selected from one or more of expanded perlite, foamed ceramic particles, and porous inorganic fiber cotton blocks.

3. The composite coating material according to claim 1, characterized in that, The weather-resistant layer is a fluorocarbon coating or a polyvinylidene fluoride coating.

4. The composite coating material according to claim 1, characterized in that, The thickness ratio of the anti-corrosion reinforcement layer, the composite sound-absorbing layer, and the weather-resistant layer is 10-50μm: 1-5mm: 15-40μm.

5. The method for preparing the composite coating material according to any one of claims 1-4, characterized in that, Includes the following steps: S1. Apply the anti-corrosion reinforcement slurry to the surface of the substrate and cure it to form a semi-cured layer; S2. The composite sound-absorbing layer slurry is coated on the surface of the semi-cured layer and cured to form a composite sound-absorbing layer that is bonded to the anti-corrosion reinforcement layer; S3. Apply the weather-resistant coating to the surface of the composite sound-absorbing layer and cure it to form a weather-resistant layer.

6. The preparation method according to claim 5, characterized in that, The curing conditions for S1 are: curing at 80-120℃ for 5-15 minutes; the curing conditions for S2 are: curing at 100-140℃ for 20-40 minutes; and the curing conditions for S3 are: curing at 80-120℃ for 10-20 minutes.

7. The application of the composite coating material according to any one of claims 1-4 in composite metal plates.

8. A composite metal plate, characterized in that, It includes a metal substrate and the composite coating material as described in any one of claims 1-4.

9. The composite metal plate according to claim 8, characterized in that, The metal substrate is selected from galvanized steel sheet, galvanized aluminum steel sheet or aluminum alloy sheet.

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