High-hardness color-coated sheet and production method thereof

Abstract

The invention discloses a high-hardness color-coated sheet and a production method thereof, the color-coated sheet comprises a base material, a middle layer on the surface of the base material and a surface coating on the top of the middle layer, and the surface coating comprises the following materials in parts by mass: 15-25 parts of polyvinylidene fluoride, 40-60 parts of silane modified polyester, 10-30 parts of pigment filler, 1-3 parts of modified carbon nitride, 0.5-1 part of a flatting agent and 0.5-1 part of a dispersing agent; the middle layer is prepared from the following materials in parts by mass: 20 to 30 parts of polymethyl methacrylate, 10 to 15 parts of polyvinylidene fluoride-hexafluoropropylene copolymer and 40 to 60 parts of ethylene-vinyl acetate copolymer. The surface coating of the color-coated sheet has relatively good hardness and wear resistance and relatively long service life; and meanwhile, the modified carbon nitride enhances the absorption of the coating on light and heat, and the color-coated sheet has good heat conduction and heat insulation performance.

Description

Technical Field

[0001] The invention relates to the technical field of color-coated plates, and in particular to a high-hardness color-coated plate and a production method thereof. Background Art

[0002] Color-coated sheets are also called coated sheets, organic coated sheets or pre-coated sheets. They are made of metal coils (cold-rolled sheets, hot-dip galvanized sheets, aluminum-coated sheets, high aluminum alloy sheets, stainless steel sheets, etc.) as the base material, and various organic coatings or plastic films are coated or laminated on the surface. Since color-coated sheets are coils that have been coated on the surface in metallurgical factories and can be directly processed into products by users, they are also called pre-coated coils. Color-coated sheets are widely used in the fields of construction, home appliances, and the automotive industry because they have both good decorative and protective properties of the outer coating and high strength and easy processing properties of the base material.

[0003] In the color-coated plate structure, the coating is located on the surface of the color-coated plate and is in direct contact with the outside world. Therefore, the coating material plays a key role in the corrosion resistance, stain resistance, appearance color and other properties of the color-coated plate. Improving the coating material can enhance the surface strength and scratch resistance of the color-coated plate, protect the surface of the color-coated plate from damage, and then ensure that the corrosion resistance, stain resistance, weather resistance, heat insulation and other properties of the color-coated plate as a whole are not affected. CN109401507A discloses a high-strength nanographene color-coated plate and a preparation method thereof. The color-coated plate includes a top coating, a bottom coating, a first passivation layer, a substrate, a second passivation layer and a back coating layer stacked in sequence. After aluminum nitride is modified by triethanolamine and β-hydroxyalkylamide, it is combined with graphene under the action of epoxy resin to form a composite material, thereby improving the overall strength of the top coating; graphene oxide is added to the bottom coating, and is connected and modified by ultra-high molecular weight polyacrylamide, and acts as a crosslinking point in the ultra-high molecular weight polyacrylamide molecule, thereby improving the strength of the bottom coating. However, although the aluminum nitride in the topcoat of this coated plate is modified, it can react violently with water, and may precipitate and contact with water in long-term use, and there is an unstable drawback. CN115216197A discloses a color-coated plate and a preparation method thereof, wherein the color-coated plate comprises a substrate, a primer layer applied on the top of the substrate, and a fine coating applied on the top of the primer layer, wherein the material of the primer layer comprises 80 to 95 parts of epoxy resin, 30 to 45 parts of acrylic, 25 to 35 parts of acetylene-butyl acrylate copolymer, 10 to 15 parts of modified lime powder, 5 to 10 parts of modified graphite powder, 15 to 25 parts of modified inorganic particles, and 1 to 5 parts of modified bentonite in mass parts, and the primer layer is made, which can enhance the bending strength and scratch resistance of the color-coated plate. However, in this method, high pressure and radiation modification are required for lime powder, graphite powder, and non-polar particles, and additional devices are required, which is not conducive to industrial batch production.

[0004] There are still some difficulties in developing color-coated sheets with high hardness and structurally stable coatings. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a high-hardness color-coated plate, comprising a substrate, an intermediate layer on the surface of the substrate, and a top coating on the top of the intermediate layer. The materials of the top coating layer include, by weight, 15~25 parts of polyvinylidene fluoride, 40~60 parts of silane-modified polyester, 10~30 parts of pigments and fillers, 1~3 parts of modified carbon nitride, 0.5~1 parts of leveling agent, 0.5~1 parts of dispersant; The materials of the intermediate layer include, by mass, 20-30 parts of polymethyl methacrylate, 10-15 parts of polyvinylidene fluoride-hexafluoropropylene copolymer, 40-60 parts of ethylene-vinyl acetate copolymer.

[0006] The topcoat of the present invention is prepared by adding polyvinylidene fluoride and silane-modified polyester. Due to its very stable fluorocarbon bond and unique molecular symmetry, polyvinylidene fluoride has strong stability and unique anti-ultraviolet performance. The main chain of the silane-modified polyester is repeatedly repeated with typical Si-O bonds, with a bond energy of up to 446 kJ / mol, which is not easily affected by sunlight and ultraviolet rays. This makes the topcoat have good mechanical properties.

[0007] Carbon nitride has the characteristics of high temperature resistance, wear resistance, high conductivity, and theoretically higher hardness than diamond. At the same time, due to its unique band gap structure and photoluminescence characteristics, it also has good ultraviolet shielding performance. Compared with the direct calcination preparation with precursors rich in carbon and nitrogen elements, the use of melamine and molecules with similar structures to melamine, such as cyanuric acid, for copolymerization and calcination can prepare carbon nitride with a larger specific surface area. At the same time, the addition of substances that can react with piperazine rings during the polymerization reaction can further polymerize. Dopamine will spontaneously polymerize in an alkaline environment to form polydopamine. After preparing carbon nitride, the present invention modifies the polydopamine on the surface, and uses the rich amino, hydroxyl and benzene ring groups of polydopamine to strengthen the interaction between carbon nitride and coating resin, thereby improving the dispersibility of carbon nitride. However, polydopamine has a certain hydrophilicity, and direct modification may increase the hydrophilicity of the coating. The present invention also introduces copper into the carbon nitride by grinding and mixing the copolymer with copper salt and then calcining it during the preparation of carbon nitride. The introduction of copper can not only strengthen the interaction between the modified carbon nitride and the coating resin, but also suppress the disadvantage of the hydrophilicity of polydopamine. In addition, based on the copper and polydopamine in the modified carbon nitride, the coating's ability to absorb light and heat is enhanced, so that the color-coated plate has good thermal conductivity and heat insulation properties.

[0008] Furthermore, the preparation method of the modified carbon nitride comprises, by weight, Dissolve 5-10 parts of melamine and 5-10 parts of cyanuric acid in 100-150 parts of dimethyl sulfoxide and stir for 2-5 hours; then add 1-3 parts of 3,4-pyridinedicarboxylic acid and continue the reaction for 3-8 hours, and collect the polymer; 5-10 parts of the polymer and 0.2-0.5 parts of the copper salt are ground and mixed to obtain a mixture, and then calcined at 400-600° C. for 3-5 hours to obtain an intermediate; 5 to 10 parts of the intermediate, 0.3 to 1 part of dopamine hydrochloride, and 150 to 200 parts of the first solvent are mixed and the pH is adjusted to be weakly alkaline, followed by stirring for reaction to obtain modified carbon nitride.

[0009] However, the reaction basically stops after most of the melamine and cyanuric acid are polymerized. Therefore, the present invention further adds 4-acetylaminopyrimidine to further promote the reaction by using the interaction, so that carbon nitride with a larger specific surface area can be prepared under the same conditions.

[0010] Furthermore, when adding 3,4-pyridinedicarboxylic acid, 4-acetylaminopyrimidine in an amount of 0.1 to 0.2 times the mass of melamine is also added.

[0011] Furthermore, the particle size of the mixture is 200-500 mesh.

[0012] Further, the first solvent includes at least one of water, ethanol, acetone, and phosphate buffer solution; The weak alkalinity refers to the pH being adjusted to 8.5-9.3.

[0013] Furthermore, the preparation method of the silane-modified polyester comprises, by parts by mass, 10-30 parts of vinyl benzoate, 50-80 parts of vinyl versatate, and 0.2-1 parts of initiator are added to 60-150 parts of the second solvent and heated for polymerization reaction, and then 60-100 parts of silane monomer and 0.1-0.3 parts of catalyst are added and heated for reaction again to obtain silane-modified polyester.

[0014] Further, the second solvent includes at least one of toluene and ethyl acetate; The silane monomer includes at least one of γ-aminopropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane; The catalyst includes at least one of an organic tin compound, a titanate compound, and a germanium compound.

[0015] Furthermore, the pigment filler includes at least one of calcium carbonate, barium sulfate, titanium dioxide and zinc oxide with a mesh size of 300-500.

[0016] Furthermore, the leveling agent is a silicone-modified polyacrylate leveling agent.

[0017] Furthermore, the dispersant is at least one of sodium polycarboxylate, potassium polyacrylate and sodium polyacrylate.

[0018] The present invention also provides a method for producing the above-mentioned high-hardness color-coated plate, comprising: Roll coating the material of the intermediate layer on the upper and lower surfaces of the substrate, followed by curing to obtain an intermediate product; The material of the top coating is rolled on the upper and lower surfaces of the intermediate product, and then cured to obtain a high-hardness color-coated plate.

[0019] It should be noted that polyvinylidene fluoride also uses a solvent 1 to 3 times its mass to help dissolve, and the solvent can be N, N-dimethylformamide, N-methylpyrrolidone, methyl vinyl ketone, dichloromethane, etc., because the solvent is completely dried and is not included in the material of the top coating. The type of substrate in the present invention does not need to be limited. According to the general understanding in the art, the substrate can be one of cold-rolled steel sheet, hot-dip galvanized sheet, aluminum-plated sheet, high aluminum alloy sheet, stainless steel sheet, etc. The type of initiator used in the present invention does not need to be strictly limited, and can be selected as needed, and can trigger a free radical reaction. For example, it can be at least one of diisopropylbenzene peroxide, dibenzoyl peroxide, azobisisobutyronitrile, azobisisoheptylonitrile, potassium persulfate, etc. The type of copper salt used in the present invention does not need to be strictly limited, and can be at least one of copper sulfate pentahydrate, copper nitrate trihydrate, copper acetate monohydrate, etc.

[0020] Compared with the prior art, the present invention has the following beneficial effects: Polyvinylidene fluoride, silane-modified polyester and modified carbon nitride are added to the formula of the top coating of the present invention, so that the coating has good hardness and wear resistance and a long service life; at the same time, based on the copper element and polydopamine contained in the modified carbon nitride, the coating's ability to absorb light and heat is enhanced, so that the color-coated plate has good thermal conductivity and heat insulation performance. DETAILED DESCRIPTION

[0021] The endpoints and any values ​​of the ranges disclosed in the present invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in the present invention.

[0022] Some of the raw materials used in the examples and comparative examples of the present invention are described as follows: Polymethyl methacrylate, model ZK5BR, from Evonik Degussa, Germany; Polyvinylidene fluoride-hexafluoropropylene copolymer, brand 2801, from Arkema, France; Ethylene-vinyl acetate copolymer, brand UL15019CC, from ExxonMobil; Polyvinylidene fluoride, brand 4000HD, from Arkema, France; Vinyl benzoate, CAS number 769-78-8; Versatile vinyl carbonate, CAS number is 51000-52-3; 3,4-pyridinedicarboxylic acid, CAS number 490-11-9; 4-Acetylaminopyrimidine, CAS number is 5221-42-1; The leveling agent selected is a silicone-modified polyacrylate leveling agent with a brand name of BYK3700, which comes from BYK Chemical Company of Germany.

[0023] Other raw materials not mentioned are common raw materials. The above content is only to help illustrate the present invention and shall not be construed as a strict limitation of the present invention. Those skilled in the art can directly purchase the same / similar raw materials from the market or prepare them by themselves. These contents will not be repeated in the examples.

[0024] The following will be combined with the specific embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Example 1 A method for producing a high-hardness color-coated plate, the steps are as follows: S1, dissolving 2 kg of polyvinylidene fluoride in 2.5 kg of N-methylpyrrolidone, and then mixing with 5 kg of silane-modified polyester, 2.5 kg of 350 mesh calcium carbonate, 0.2 kg of modified carbon nitride, 0.08 kg of silicone-modified polyacrylate leveling agent, and 0.75 kg of sodium polyacrylate, and heating to 65 ° C and stirring at a speed of 150 rpm for 20 min to obtain a top coating material; S2, 2.5 kg of polymethyl methacrylate, 1.3 kg of polyvinylidene fluoride-hexafluoropropylene copolymer, and 5.5 kg of ethylene-vinyl acetate copolymer were mixed, and stirred at 120° C. and 120 rpm for 15 min to obtain a material for the middle layer; S3, preheating a 0.5 mm thick Q235 cold-rolled steel plate to 60°C, then roller-coating the intermediate layer material on the upper and lower surfaces thereof, baking at 130°C for 30s, and air-cooling and curing to obtain an intermediate product; S4, the top coating material is rolled on the upper and lower surfaces of the intermediate product, and then baked at 150°C for 30s, and air-cooled to solidify to obtain a high-hardness color-coated plate. Among them, the high-hardness color-coated plate includes a cold-rolled steel plate, an intermediate layer on the surface of the cold-rolled steel plate, and a top coating on the top of the intermediate layer. The thickness of the intermediate layer and the top coating are 30μm and 50μm respectively.

[0026] Wherein, the preparation method of silane-modified polyester is: 2.5 kg of vinyl benzoate, 6.5 kg of vinyl versatate, and 0.08 kg of azobisisobutyronitrile were added to 12 kg of ethyl acetate, the temperature was raised to 65° C., and the polymerization reaction was carried out under reflux for 5 hours. Then, 8 kg of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane and 0.025 kg of dibutyltin dilaurate were added, and the temperature was raised to 80° C. again, and the reaction was carried out under reflux for 2 hours to obtain silane-modified polyester.

[0027] The preparation method of modified carbon nitride is: T1, dissolving 80g of melamine and 85g of cyanuric acid in 1200g of dimethyl sulfoxide and stirring at 150rpm for 3h; then adding 20g of 3,4-pyridinedicarboxylic acid and continuing the reaction for 6h, filtering and drying in a constant temperature oven at 120°C for 12h to obtain a polymer; T2, grinding and mixing 75 g of the polymer and 3 g of copper sulfate pentahydrate, and sieving to obtain a mixture with a particle size of 300 mesh, and then transferring to a muffle furnace in an air atmosphere at 450° C. and calcining for 4 h to obtain an intermediate; T3. Mix 75 g of the intermediate, 8 g of dopamine hydrochloride and 1500 g of ethanol at a rotation speed of 350 rpm and adjust the pH to 9.1, then stir and react for 5 h. After filtering, place in a constant temperature oven at 80° C. and dry for 12 h to obtain modified carbon nitride.

[0028] Example 2 The method is basically the same as Example 1, except that: the preparation method of the modified carbon nitride is: T1, dissolving 80g of melamine and 85g of cyanuric acid in 1200g of dimethyl sulfoxide and stirring at 150rpm for 3h; then adding 20g of 3,4-pyridinedicarboxylic acid and 8g of 4-acetylaminopyrimidine and continuing the reaction for 6h, filtering and drying in a constant temperature oven at 120°C for 12h to obtain a polymer; T2, grinding and mixing 75 g of the polymer and 3 g of copper sulfate pentahydrate, and sieving to obtain a mixture with a particle size of 300 mesh, and then transferring to a muffle furnace in an air atmosphere at 450° C. and calcining for 4 h to obtain an intermediate; T3. Mix 75 g of the intermediate, 8 g of dopamine hydrochloride and 1500 g of ethanol at a rotation speed of 350 rpm and adjust the pH to 9.1, then stir and react for 5 h. After filtering, place in a constant temperature oven at 80° C. and dry for 12 h to obtain modified carbon nitride.

[0029] Example 3 Compared with Example 2, the difference is that the amount of 4-acetylaminopyrimidine added in step T1 is 12 g.

[0030] Example 4 Compared with Example 2, the difference is that the amount of 4-acetylaminopyrimidine added in step T1 is 16 g.

[0031] Comparative Example 1 Compared with Example 2, the difference is that the amount of 4-acetylaminopyrimidine added in step T1 is 6 g.

[0032] Comparative Example 2 Compared with Example 2, the difference is that the amount of 4-acetylaminopyrimidine added in step T1 is 20 g.

[0033] Comparative Example 3 Compared with Example 1, the difference is that: copper sulfate pentahydrate is not added in step T2, and the polymer is ground to 300 mesh and directly calcined.

[0034] Comparative Example 4 Compared with Example 3, the difference is that: copper sulfate pentahydrate is not added in step T2, and the polymer is ground to 300 mesh and directly calcined.

[0035] Comparative Example 5 Compared with Example 1, the difference is that in step S1, carbon nitride is used instead of modified carbon nitride.

[0036] The preparation method of carbon nitride is: T1, dissolving 80g of melamine and 85g of cyanuric acid in 1200g of dimethyl sulfoxide and stirring at 150rpm for 3h; then adding 20g of 3,4-pyridinedicarboxylic acid and 12g of 4-acetylaminopyrimidine and continuing the reaction for 6h, filtering and drying in a constant temperature oven at 120°C for 12h to obtain a polymer; T2. Grind 75 g of the polymer and sieve it to a particle size of 300 mesh, then transfer it to a muffle furnace in an air atmosphere at 450° C. and calcine it for 4 h to obtain carbon nitride.

[0037] Comparative Example 6 Compared with Example 1, the difference is that no modified carbon nitride is added in step S1.

[0038] Test Case The specific surface area and average pore size of the carbon nitride materials prepared in the examples and comparative examples were tested by nitrogen adsorption and desorption. The results are shown in Table 1.

[0039] Table 1 Specific surface area and average pore size of carbon nitride materials It can be seen from Table 1 that the carbon nitride material prepared by the embodiment of the present invention has a larger specific surface area and average pore size, and at the same time, Example 2 to Example 4 is significantly larger than Example 1, which shows that the introduction of 4-acetylaminopyrimidine promotes the further polymerization of melamine and cyanuric acid, so that the formed polymer calcination has a richer pore structure. Example 2 to Example 4 and Comparative Examples 1 to 2 illustrate that the addition of 4-acetylaminopyrimidine has a preferred value, and too little or too much is not conducive to the improvement of specific surface area and pore size. Comparative Examples 3 and Comparative Examples 4 were not ground with copper sulfate pentahydrate after the polymer was prepared. Correspondingly, the specific surface area was almost unchanged compared to Example 1 and Example 3, but the pore size was significantly reduced, which shows that the introduction of copper will not bring obvious etching to the carbon nitride collective, but it effectively regulates the pore size. The carbon nitride prepared in Comparative Example 5 has not been modified by the introduction of copper and polydopamine compared to the modified carbon nitride of Example 3, indicating that the introduction of polydopamine can slightly increase the specific surface area, but has almost no effect on the pore size. Using a carbon nitride material with a larger specific surface area has more binding sites, which is beneficial for its good dispersion in the top coating material.

[0040] The water contact angle of the top coating of the color-coated plate was tested by a water contact angle tester; the hardness of the top coating of the color-coated plate was tested with reference to the standard GB / T 6739-2022 "Determination of paint film hardness by pencil method for paints and varnishes"; the surface of the top coating of the color-coated plate was abraded by a JM-1 paint film abrasion tester, and the weight loss of the top coating indicated the wear resistance. The smaller the weight loss, the better the wear resistance. The test results are shown in Table 2.

[0041] Table 2 Hardness and weight loss results of top coating It can be seen from Table 2 that the top coating of Comparative Example 6 without adding carbon nitride has good hydrophobic properties, and the water contact angle is 140°; the water contact angle of Comparative Example 5 without polydopamine modification has also decreased, and compared with Example 1 and Example 3, the water contact angles of Comparative Examples 3 and Comparative Examples 4 have significantly decreased. This is because although the modification of polydopamine improves the dispersion of modified carbon nitride in the top coating, the presence of the hydrophilic functional group of polydopamine also improves the hydrophilicity of the top coating, and the introduction of copper makes the modified carbon nitride more effective with polyvinylidene fluoride and silane-modified polyester, and the hydrophilic group is not easy to distribute on the surface, thereby suppressing the disadvantages of polydopamine modification. At the same time, the amount of 4-acetylaminopyrimidine added also has a certain effect on carbon nitride, because the synergy of the multiple effects of 4-acetylaminopyrimidine on the polymerization reaction, the introduction of copper, and the modification of polydopamine makes Example 3 have the largest water contact angle, reaching 151°. It can also be seen that both the embodiments of the present invention and the comparative examples have a high hardness, both higher than the 3H level, because polyvinylidene fluoride and silane-modified polyester have high mechanical strength. The hardness of comparative example 5 is lower than that of comparative example 6, which shows that the direct addition of carbon nitride instead of polydopamine modification may reduce the strength of the topcoat due to poor dispersibility. Example 3 has the highest strength and the smallest weight loss rate, because the modified carbon nitride with a larger specific surface area can be well dispersed in the topcoat matrix, thereby improving the hardness and wear resistance of the topcoat.

[0042] Referring to HG / T 4341-2012 “Heat-reflective coatings for metal surfaces”, the thermal insulation temperature difference test was carried out on the color-coated panels prepared in the examples and comparative examples. The thermal insulation temperature difference results of the samples are shown in Table 3.

[0043] Table 3 Insulation temperature difference results It can also be seen from the test results in Table 3 that the color-coated plate prepared in the embodiment of the present invention also has good thermal insulation performance, which is derived from the good absorption of light and heat by the well-distributed polydopamine and copper in the modified carbon nitride and the good thermal conductivity of carbon nitride itself.

[0044] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-hardness color-coated plate, comprising a substrate, an intermediate layer on the surface of the substrate, and a top coating on the top of the intermediate layer, characterized in that: The materials of the top coating layer include, by weight, 15~25 parts of polyvinylidene fluoride, 40~60 parts of silane-modified polyester, 10~30 parts of pigments and fillers, 1~3 parts of modified carbon nitride, 0.5~1 parts of leveling agent, 0.5~1 parts of dispersant; The materials of the intermediate layer include, by mass, 20-30 parts of polymethyl methacrylate, 10-15 parts of polyvinylidene fluoride-hexafluoropropylene copolymer, 40-60 parts of ethylene-vinyl acetate copolymer.

2. The high hardness color-coated plate according to claim 1, characterized in that: The preparation method of the modified carbon nitride comprises, by weight, Dissolve 5-10 parts of melamine and 5-10 parts of cyanuric acid in 100-150 parts of dimethyl sulfoxide and stir for 2-5 hours; then add 1-3 parts of 3,4-pyridinedicarboxylic acid and continue the reaction for 3-8 hours, and collect the polymer; 5-10 parts of the polymer and 0.2-0.5 parts of the copper salt are ground and mixed to obtain a mixture, and then calcined at 400-600° C. for 3-5 hours to obtain an intermediate; 5 to 10 parts of the intermediate, 0.3 to 1 part of dopamine hydrochloride, and 150 to 200 parts of the first solvent are mixed and the pH is adjusted to be weakly alkaline, followed by stirring for reaction to obtain modified carbon nitride.

3. The high hardness color-coated plate according to claim 2, characterized in that: When adding 3,4-pyridinedicarboxylic acid, 4-acetylaminopyrimidine in an amount of 0.1 to 0.2 times the mass of melamine is also added; The particle size of the mixture is 200-500 meshes.

4. The high hardness color-coated plate according to claim 2, characterized in that: The first solvent includes at least one of water, ethanol, acetone, and phosphate buffer solution; The weak alkalinity refers to the pH being adjusted to 8.5-9.

3.

5. The high hardness color-coated plate according to claim 1, characterized in that: The preparation method of the silane-modified polyester comprises, by parts by mass, 10-30 parts of vinyl benzoate, 50-80 parts of vinyl versatate, and 0.2-1 parts of initiator are added to 60-150 parts of the second solvent and heated for polymerization reaction, and then 60-100 parts of silane monomer and 0.1-0.3 parts of catalyst are added and heated for reaction again to obtain silane-modified polyester.

6. The high hardness color-coated plate according to claim 5, characterized in that: The second solvent comprises at least one of toluene and ethyl acetate; The silane monomer includes at least one of γ-aminopropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane; The catalyst includes at least one of an organic tin compound, a titanate compound, and a germanium compound.

7. The high hardness color-coated plate according to claim 1, characterized in that: The pigment and filler include at least one of 300-500 mesh calcium carbonate, barium sulfate, titanium dioxide and zinc oxide.

8. The high hardness color-coated plate according to claim 1, characterized in that: The leveling agent is a silicone-modified polyacrylate leveling agent.

9. The high hardness color-coated plate according to claim 1, characterized in that: The dispersant is at least one of sodium polycarboxylate, potassium polyacrylate and sodium polyacrylate.

10. A method for producing a high-hardness color-coated plate according to any one of claims 1 to 9, characterized in that: include, Roll coating the material of the intermediate layer on the upper and lower surfaces of the substrate, followed by curing to obtain an intermediate product; The material of the top coating is rolled on the upper and lower surfaces of the intermediate product, and then cured to obtain a high-hardness color-coated plate.

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