Composite coating material as well as preparation method and application thereof

Abstract

The invention 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 anti-corrosion enhancement layer, a composite sound absorption layer and a weather-proof layer which are sequentially stacked and combined. According to the invention, three functions of corrosion prevention, sound absorption and weather resistance are integrated in an integrated coating system, and through accurate design and synergistic effect of each functional layer, excellent adhesive force and corrosion resistance, efficient broadband sound absorption capability and good weather resistance protection are simultaneously realized in a single coating system. In addition, the preparation method is clear in step, conventional coating and curing processes are adopted, curing conditions of all layers are mild and controllable, the whole process does not need complex assembling or filling steps, and the preparation method is suitable for being implemented on a metal plate continuous production line and beneficial to large-scale application and popularization.

Description

TECHNICAL FIELD

[0001] 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. BACKGROUND

[0002] Metal building boards such as color steel profiled sheets and steel bar truss floor support plates are widely used due to their high strength and convenient construction, but their noise control ability is generally weak. At present, in order to improve the sound absorption performance of such metal boards, the construction method of "perforated metal plate + back cavity filled with porous sound-absorbing material (such as glass wool, rock wool)" is usually adopted. However, this method has several obvious defects: 1) complex structure, significant increase in system weight; 2) the sound-absorbing material is prone to settlement or moisture, resulting in performance degradation or even failure; 3) the bonding force between the porous material and the metal plate is weak, affecting the overall structural strength and durability; 4) the corrosion-resistant coating (such as polyester paint) of the traditional color steel plate mainly plays a decorative and basic rust-proof role, and its adhesion to the substrate, weather resistance and enhancement of the overall structural performance are limited.

[0003] Therefore, it is urgent to develop an integrated functional material that can be firmly combined with the metal substrate, integrate long-acting active corrosion prevention, high-efficiency broadband sound absorption and good workability, and can be simply applied to the surface of the metal plate. SUMMARY

[0004] The present application aims to solve the technical problems of the existing metal boards in noise control, long-acting corrosion prevention, structural strength and durability by providing a composite coating material and a preparation method and application thereof, which is composed of a corrosion-resistant reinforcing layer, a composite sound-absorbing layer and a weather-resistant layer.

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

[0006] Preferably, the damping filler is selected from one or more of rubber powder, vermiculite, closed-cell ceramic microbeads; the porous sound-absorbing aggregate is selected from one or more of expanded perlite, foamed ceramic particles, 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 close to the corrosion-resistant reinforcing layer is smaller than the average pore size on the side away from the corrosion-resistant reinforcing layer.

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

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

[0010] The present application also provides a preparation method of the composite coating material, comprising the following steps: S1. coating a corrosion-resistant reinforcing layer slurry on the surface of a substrate to form a semi-cured layer after curing; S2. coating a composite sound-absorbing layer slurry on the surface of the semi-cured layer to form a composite sound-absorbing layer combined with the corrosion-resistant reinforcing layer after curing; S3. coating a weather-resistant layer paint on the surface of the composite sound-absorbing layer to form a weather-resistant layer after curing.

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

[0012] The present application also provides the use of the composite coating material in a composite metal sheet.

[0013] The present application also provides a composite metal sheet comprising a metal substrate and the composite coating material.

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

[0015] The present application has the following advantages: 1. The present application provides a composite coating material composed of a corrosion-resistant reinforcing layer, a composite sound-absorbing layer, and a weather-resistant layer stacked and combined in sequence. The present application integrates the functions of corrosion resistance, sound absorption, and weather resistance into an integrated coating system, and through the precise design and synergistic effect of each functional layer, it simultaneously achieves excellent adhesion and corrosion resistance, high-efficiency wide-band sound-absorbing capacity, and good weather protection in a single coating system. Compared with the traditional "perforated plate + rear cavity filling" complex structure, the structure of the present application is greatly simplified, and the construction is convenient, which avoids the problems of a large increase in self-weight, easy settlement and moisture absorption of sound-absorbing materials, and weak bonding force with the substrate caused by the complex structure.

[0016] 2. In the anticorrosion enhancement layer, the epoxy-modified acrylic resin emulsion provides a good film-forming property and adhesion base; the silica sol enhances the compactness and hardness of the coating layer; the flaky zinc powder provides long-term active anticorrosion protection; the mica powder further enhances the permeability resistance and mechanical strength of the coating layer; the addition of the silane coupling agent and the wetting dispersant 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 gives the coating layer good flexibility and adhesive strength; 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 to generate bubbles during the curing process, and together with the inherent pores of the aggregate, forms a complex porous network, greatly increasing the sound wave propagation path and energy loss.

[0018] 4. The present application controls the formulation and curing process of the composite sound-absorbing layer slurry, so that the sound-absorbing layer after curing forms a gradient porous structure with small average pore size on the side close to the anticorrosion enhancement layer and large average pore size on the side far away. This gradient structure is beneficial to realize the continuous matching of sound wave impedance in the thickness direction of the coating, reduces the reflection of sound waves at the interface, promotes the deep penetration and efficient dissipation of sound waves into the interior of the coating, and thus realizes high-efficiency sound absorption in a wider frequency band at a relatively thin thickness.

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

[0020] 6. The preparation method of the present application has clear steps, and uses conventional coating and curing processes, and the curing conditions of each layer are mild and controllable. In particular, by coating the composite sound-absorbing layer slurry on the semi-cured anticorrosion enhancement layer, chemical bonding and physical anchoring between the two layers are realized, ensuring the interlayer bonding force. The entire 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.

[0021] 7. The metal plate (such as galvanized steel plate, galvanized aluminum steel plate, aluminum alloy plate) of the composite coating material of the present application, while maintaining the original high strength, light weight, and convenient construction of the metal substrate, integrates excellent sound absorption and noise reduction, long-term corrosion resistance, and weather resistance, and can be widely used in building envelope structures, industrial plants, transportation facilities, and other fields that have high requirements for acoustic environment and durability. DETAILED DESCRIPTION

[0022] The application provides a composite coating material, which is composed of an anticorrosion reinforcing layer, a composite sound-absorbing layer and a weather-resistant layer which are sequentially stacked and combined. The anticorrosion reinforcing layer comprises the following raw materials in mass fraction: 30-50 parts of epoxy-modified acrylic resin emulsion, 10-25 parts of silica sol, 5-15 parts of flaky zinc powder, 3-10 parts of mica powder, 0.5-2 parts of silane coupling agent, 0.3-1 part of wet dispersing agent, 3-8 parts of water-based curing agent and 15-40 parts of water. The composite sound-absorbing layer comprises the following raw materials in mass fraction: 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.

[0023] In the application, the solid content of the epoxy-modified acrylic resin emulsion is 45-55%, the solid content of the silica sol is 20-30%, the flaky zinc powder has a flaky diameter of 10-50 μm, the mica powder has a particle diameter of 600-1000 mesh, the silane coupling agent is selected from KH-560, the wet dispersing agent is selected from BYK-190, and the water-based curing agent is selected from a water-based polyamide curing agent.

[0024] In the application, the solid content of the water-based 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 the application, the damping filler is selected from one or more of rubber powder, vermiculite and closed-cell ceramic microbeads, the particle diameter 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 block, and the particle diameter of the porous sound-absorbing aggregate is 0.5-3 mm.

[0026] In the application, the composite sound-absorbing layer has a pore size gradient distribution, wherein the average pore size on the side close to the anticorrosion reinforcing layer is smaller than the average pore size on the side far from the anticorrosion reinforcing layer.

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

[0028] In the application, the thickness ratio of the anticorrosion reinforcing layer, the composite sound-absorbing layer and the weather-resistant layer is 10-50 μm: 1-5 mm: 15-40 μm.

[0029] The application further provides a preparation method of the composite coating material, which comprises the following steps: S1. coating an anticorrosion reinforcing layer slurry on the surface of a substrate to form a semi-cured layer; S2. coating a composite sound-absorbing layer slurry on the surface of the semi-cured layer to form a composite sound-absorbing layer combined with the anticorrosion reinforcing layer; S3. Apply weather-resistant coating to the surface of the composite sound-absorbing layer and cure to form a weather-resistant layer.

[0030] In the present application, in S1, the preparation process of the corrosion-resistant reinforcing layer slurry comprises: mixing water, wetting dispersant, silane coupling agent, silica sol, flaky zinc powder and mica powder, uniformly dispersing at 800-1500 rpm, then adding epoxy-modified acrylic resin emulsion, uniformly stirring at 200-400 rpm, and finally adding water-based curing agent to adjust the viscosity of the system to 30-50 s with a 4-cup, to obtain the corrosion-resistant reinforcing layer slurry.

[0031] In the present application, in S1, the preparation process of the composite sound-absorbing layer slurry comprises: uniformly mixing water, foam stabilizer and water-based polyurethane dispersion, adding damping fillers and porous sound-absorbing aggregates to stir to form a uniform paste, to obtain a base paste; before coating, adding a chemical foaming agent to the base paste and stirring at 1400-1600 rpm to obtain the composite sound-absorbing layer slurry.

[0032] In the present application, the curing conditions in S1 are 80-120℃ for 5-15 min; the curing conditions in S2 are 100-140℃ for 20-40 min; and the curing conditions in S3 are 80-120℃ for 10-20 min.

[0033] In the present application, the composite sound-absorbing layer forms a pore size distribution with gradient characteristics during the curing process. The mechanism is that heat is transmitted upward from the substrate side, resulting in a temperature gradient along the thickness direction of the slurry. The slurry layer close to the substrate is heated first, and the foaming agent decomposes to form fine bubbles in the environment with high viscosity; while the slurry layer away from the substrate foams at a later time, the overall temperature of the system rises, the viscosity decreases, and the bubbles generated in the lower layer float up and merge under the action of buoyancy, thereby forming larger pores. At the same time, the semi-cured corrosion-resistant reinforcing layer restricts the downward development of the bubbles, promoting the upward growth of the bubbles.

[0034] The gradient porous structure with smaller average pore size close to the corrosion-resistant reinforcing layer side and larger average pore size away from the side is beneficial to the continuous matching of the acoustic impedance, thereby realizing wide-frequency and high-efficiency sound absorption.

[0035] In the present application, after S3, cooling and roll forming are performed to obtain a substrate containing the composite coating material.

[0036] The present application also provides the use of the composite coating material in a composite metal plate.

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

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

[0039] The present application is further described below in conjunction with examples. Unless otherwise defined, the technical terms or scientific terms used in the present application shall be the commonly understood meanings by those skilled in the art. The features mentioned above or the features mentioned in the specific examples can be combined in any manner, and these specific examples are only used to illustrate the present application and not to limit the scope of the present application.

[0040] In the following examples and comparative examples of the present application, the epoxy-modified acrylic resin emulsion is purchased from Zhenxin Resin (Shanghai) Co., Ltd.; the silica sol is purchased from Qingdao Haoyang Chemical Co., Ltd.; the water-based polyamide curing agent is purchased from Hansen Chemical Trade (Shanghai) Co., Ltd.; the water-based polyurethane dispersion is purchased from Wanhua Chemical Group Co., Ltd.; the closed-cell ceramic microbead is purchased from Jiangsu Jinlibao Adhesive Products Co., Ltd.; the foamed ceramic particle is purchased from Guangdong Jinyi Ceramic Group Co., Ltd.; the porous inorganic fiber cotton block is purchased from Huamei Energy-saving Technology Group Co., Ltd.; the polyvinylidene fluoride coating is purchased from Pompeii Coatings (Shanghai) Co., Ltd.; and the fluorocarbon coating is purchased from AkzoNobel Paints (China) Co., Ltd.

[0041] Example 1 The present example provides a composite metal sheet comprising a composite coating material, and a preparation method thereof, which comprises the following steps: Take a galvanized aluminum steel sheet with a thickness of 0.8mm, and sequentially perform alkaline cleaning and degreasing, water washing, drying and iron-based phosphating treatment to obtain a clean surface with good adhesion activity, thereby obtaining a pretreated steel sheet.

[0042] Take 20 parts of water, add 0.5 parts of BYK-190, 1 part of KH-560, 15 parts of silica sol with a solid content of 25%, 10 parts of flaky zinc powder with a flake diameter of 30μm, 5 parts of mica powder with a particle size of 800 mesh, and high-speed disperse in a dispersing machine at a speed of 1200rpm for 15min; then slowly add 40 parts of epoxy-modified acrylic resin emulsion with a solid content of 50%, and stir at a low speed of 300rpm for 10min; finally, add 5 parts of water-based polyamide curing agent, and adjust the viscosity to 40s in a 4-cup coating machine, thereby obtaining an anti-corrosion and reinforcing layer slurry. Roll coat the anti-corrosion and reinforcing layer slurry on the pretreated steel sheet, and cure at 100℃ for 8min to form a semi-cured layer.

[0043] Take 18 parts of water, add 0.3 parts of sodium dodecyl sulfate, 30 parts of waterborne polyurethane dispersion with solid content of 40%, mix evenly; add 20 parts of rubber powder with particle size of 100 mesh, 15 parts of closed-cell ceramic microbeads with particle size of 80 mesh, 35 parts of expanded perlite with particle size of 1-2 mm, and stir into a uniform paste. Before spraying, add 2 parts of ammonium bicarbonate to the paste, and stir at 1500 rpm for 30 s to initiate foaming. Immediately use a foam spraying machine to uniformly spray the slurry onto the semi-cured layer, and cure at 120℃ for 30 min to form a composite sound-absorbing layer combined with the corrosion-resistant reinforcing layer.

[0044] Roll the polyvinylidene fluoride coating on the surface of the composite sound-absorbing layer, and cure at 100℃ for 15 min to form a weather-resistant layer.

[0045] After cooling to room temperature, roll-forming is performed to obtain a composite metal plate containing a composite coating material, wherein the thickness of the corrosion-resistant reinforcing layer is 30 μm, the thickness of the composite sound-absorbing layer is 3 mm, and the thickness of the weather-resistant layer is 25 μm.

[0046] Example 2 The present embodiment provides a composite metal plate containing a composite coating material, and the preparation method thereof comprises the following steps: Take a galvanized steel plate with a thickness of 1 mm, and sequentially perform alkaline cleaning and degreasing, water washing, drying, and iron-based phosphating treatment to obtain a clean surface with good adhesion activity, thereby obtaining a pretreated steel plate.

[0047] Take 23 parts of water, add 0.8 parts of BYK-190, 1.5 parts of KH-560, 20 parts of silica sol with a solid content of 25%, 8 parts of flaky zinc powder with a flake size of 30 μm, and 8 parts of mica powder with a particle size of 800 mesh, and high-speed disperse in a dispersing machine at a speed of 1000 rpm for 20 min; then slowly add 45 parts of 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 of waterborne polyamide curing agent, and adjust the viscosity to 45 s in a 4-cup test to obtain a corrosion-resistant reinforcing layer slurry. Roll-coat the corrosion-resistant reinforcing layer slurry on the pretreated steel plate, and cure at 110℃ for 10 min to form a semi-cured layer.

[0048] Take 22 parts of water, add 0.4 parts of sodium dodecyl sulfate, and 35 parts of waterborne polyurethane dispersion with a solid content of 40%, and mix evenly; add 30 parts of vermiculite with a particle size of 150 mesh, and 40 parts of foamed ceramic particles with a particle size of 1-3 mm, and stir into a uniform paste. Before spraying, add 1.5 parts of azodicarbonamide to the paste, and stir at a high speed of 1400 rpm for 35 s to initiate foaming. Immediately use a foam spraying machine to uniformly spray the slurry onto the semi-cured layer, and cure at 130℃ for 25 min to form a composite sound-absorbing layer combined with the corrosion-resistant reinforcing layer.

[0049] A fluorocarbon coating is roll-coated on the surface of the composite sound-absorbing layer, and cured at 110°C for 12 min to form a weather-resistant layer.

[0050] After cooling to room temperature, the roll-pressing molding is performed to obtain a composite metal plate comprising the composite coating material, wherein the thickness of the corrosion-resistant reinforcing layer is 40 μm, the thickness of the composite sound-absorbing layer is 4 mm, and the thickness of the weather-resistant layer is 20 μm.

[0051] Example 3 The present example provides a composite metal plate comprising a composite coating material, and the preparation method thereof comprises the following steps: A 5052 aluminum alloy plate with a thickness of 0.5 mm is subjected to alkaline cleaning and degreasing, water washing, drying and chromate passivation treatment in sequence to obtain a clean surface with good adhesion activity, thereby obtaining a pretreated plate.

[0052] Take 15 parts of water, add 0.3 parts of BYK-190, 0.8 parts of KH-560, 12 parts of silica sol with a solid content of 25%, 6 parts of flaky zinc powder with a flake diameter of 30 μm, and high-speed disperse in a dispersing machine at a speed of 1500 rpm for 10 min; then slowly add 35 parts of 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 of water-based polyamide curing agent, and adjust the viscosity to 35 s in a coating-4 cup, thereby obtaining a corrosion-resistant reinforcing layer slurry. The corrosion-resistant reinforcing layer slurry is roll-coated on the pretreated plate, and cured at 90°C for 12 min to form a semi-cured layer.

[0053] Take 12 parts of water, add 0.2 parts of sodium dodecyl sulfate, 25 parts of water-based polyurethane dispersion with a solid content of 40%, and mix uniformly; add 12.5 parts of rubber powder with a particle size of 80 mesh, 12.5 parts of closed-cell ceramic microbeads with a particle size of 50 mesh, and 30 parts of porous inorganic fiber cotton block with a particle size of 0.5-1.5 mm, and stir into a uniform paste. Before spraying, add 1 part of ammonium bicarbonate to the paste, and stir at a high speed of 1600 rpm for 25 s to initiate foaming. Immediately use a foam spraying machine to uniformly spray the slurry onto the semi-cured layer, and cure at 110°C for 35 min to form a composite sound-absorbing layer combined with the corrosion-resistant reinforcing layer.

[0054] A polyvinylidene fluoride coating is roll-coated on the surface of the composite sound-absorbing layer, and cured at 90°C for 18 min to form a weather-resistant layer.

[0055] After cooling to room temperature, the roll-pressing molding is performed to obtain a composite metal plate comprising the composite coating material, wherein the thickness of the corrosion-resistant reinforcing layer is 15 μm, the thickness of the composite sound-absorbing layer is 1.5 mm, and the thickness of the weather-resistant layer is 30 μm.

[0056] Comparative Example 1 This comparative example provides a composite metal sheet comprising a composite coating material, differing from Example 1 in that the preparation and application of the corrosion enhancing layer slurry is omitted.

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

[0058] Comparative Example 3 This comparative example uses a galvanized perforated sheet (perforation rate of 20%) having a thickness of 0.8 mm, and a sound absorbing layer having an overall thickness of 50 mm is provided on the back thereof, the sound absorbing layer being filled with centrifugal glass wool having a density of 32 kg / m 3 .

[0059] Experimental Example 1 The samples obtained in Examples 1-3 and Comparative Examples 1-3 were respectively subjected to performance tests, and the test results are recorded in Table 1. Among them, the sound absorption performance test was carried out according to GB / T 20247-2006 "Acoustics-Determination of sound absorption coefficient by impedance tube method-Part 2: Transfer function method", using a B&K 4206 type impedance tube test system. Before testing, each sample was cut into a standard test piece with a diameter of 100 mm and installed on a rigid test piece frame in accordance with the standard requirements, ensuring that the back is a closed rigid wall condition. The sound absorption coefficient of the sample at five 1 / 3 octave center frequencies of 250 Hz, 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz was measured, and the arithmetic mean value was calculated as the average sound absorption coefficient. The adhesion test was carried out according to GB / T 9286-1998 "Paints and varnishes Cross-cut test for coatings", using a multi-blade cutting tool with a spacing of 1 mm to cross-cut the coating, and the adhesion grade between the corrosion enhancing layer and the metal substrate (or between the composite sound absorbing layer and the substrate in Comparative Example 1) was evaluated (0 grade is the best, 5 grade is the worst). The neutral salt spray resistance performance test was carried out according to GB / T 1771-2007 "Paints and varnishes-Determination of resistance to neutral salt spray", after a single scratch (penetrating to the substrate) was made on the surface of the sample, the sample was placed in a salt spray chamber for 500 hours of neutral salt spray (NSS) test (test conditions: 5% NaCl solution, pH 6.5-7.2, chamber temperature 35°C). After the test, the sample was washed and dried, and the maximum width of the rusting or peeling of the coating on one side was measured.

[0060] Table 1 Test Results

[0061] Therefore, the application adopts the composite coating material, the preparation method and the application, effectively overcomes the defects of the prior art, and provides an innovative solution integrating strong adhesion, long-acting active corrosion prevention, efficient broadband sound absorption, excellent weather resistance and convenient construction.

[0062] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, but not to limit them. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can still be modified or replaced by equivalents, and these modifications or replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A composite coating material, characterized by, The anticorrosion reinforcing layer, the composite sound-absorbing layer and the weather-resistant layer are sequentially stacked and combined; The anticorrosion reinforcing layer comprises the following raw materials by mass fraction: 30-50 parts of epoxy-modified acrylic resin emulsion, 10-25 parts of silica sol, 5-15 parts of flaky zinc powder, 3-10 parts of mica powder, 0.5-2 parts of silane coupling agent, 0.3-1 part of wet dispersing agent, 3-8 parts of water-based curing agent, and 15-40 parts of water; The composite sound-absorbing layer comprises the following raw materials by mass fraction: 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.

2. The composite coating material of claim 1, wherein, The damping filler is selected from one or more of rubber powder, vermiculite and closed-cell ceramic microbeads; and the porous sound-absorbing aggregate is selected from one or more of expanded perlite, foamed ceramic particles and porous inorganic fiber wool block.

3. The composite coating material according to claim 1 or 2, characterized in that The composite sound-absorbing layer has a pore size gradient distribution, wherein the average pore size on the side close to the anticorrosion reinforcing layer is smaller than the average pore size on the side away from the anticorrosion reinforcing layer.

4. The composite coating material of claim 1, wherein, The weather-resistant layer is a fluorocarbon coating layer or a polyvinylidene fluoride coating layer.

5. The composite coating material of claim 1, wherein, The thickness ratio of the anticorrosion reinforcing layer, the composite sound-absorbing layer and the weather-resistant layer is 10-50 μm: 1-5 mm: 15-40 μm.

6. The method of making a composite coating material according to any one of claims 1 to 5, characterized in that, The method comprises the following steps: S1. applying an anticorrosion reinforcing layer slurry to the surface of a substrate and curing to form a semi-cured layer; S2. applying a composite sound-absorbing layer slurry to the surface of the semi-cured layer and curing to form a composite sound-absorbing layer combined with the anticorrosion reinforcing layer; S3. applying a weather-resistant layer coating to the surface of the composite sound-absorbing layer and curing to form a weather-resistant layer.

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

8. Use of the composite coating material according to any one of claims 1-5 in a composite metal plate.

9. A clad metal sheet, characterized by The composite coating material according to any one of claims 1-5 is applied to a metal substrate.

10. The composite metal plate according to claim 9, wherein The metal substrate is selected from a galvanized steel plate, a galvanized aluminum steel plate or an aluminum alloy plate.

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