Thermal insulation metal-coated sheet for building materials and method for manufacturing the same

Abstract

The application relates to the technical field of building material materials, and discloses a heat-insulating metal laminated plate for building materials and a preparation method thereof.The heat-insulating metal laminated plate is composed of an epoxy resin coating layer, a PVC film layer, a metal plate, an ASA film layer and an epoxy resin coating layer; tetraamino biphenyl imidazole, 4,4'-amino diphenyl ether and dianhydride monomers are subjected to crosslinking polymerization reaction to obtain polyimide aerogel, which is then added into epoxy resin to obtain a coating layer; the polyimide aerogel has a three-dimensional porous network structure, a larger specific surface area and richer pore structure, reduces the energy transmission efficiency of gas molecules through collision, improves the heat-insulating performance of the aerogel, and is added into the epoxy resin coating layer, which is beneficial to preventing heat transmission, reducing the thermal conductivity of the coating layer and the metal laminated plate and improving the heat preservation and heat insulation performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building materials, in particular to a heat-insulating metal laminated sheet for building materials and a preparation method thereof. BACKGROUND

[0002] Metal laminated sheets have been widely used in roofs and walls due to their high strength and long service life, but heat insulation is a requirement that cannot be bypassed for traditional building materials. The thermal conductivity of metal is much higher than that of polymer materials, and the size ratio of metal to polymer material in the design of metal laminated sheets is about 5:1-10:1. The thickness of the polymer material is generally only 0.02-0.2mm, and it is difficult to achieve foaming and laminating requirements. Referring to the process of color steel insulation, an additional insulation layer is attached, which is relatively open. For a non-fully sealed substrate, it is not conducive to protection and has poor adhesion strength, which is easy to separate.

[0003] The development of aerogel technology provides a lower-cost heat insulation protection, but the mechanical strength of aerogel is low. Adding aerogel to an epoxy resin coating will affect the mechanical properties of the coating. In polymer-based aerogels, polyimide aerogels have attracted widespread attention due to their excellent high-temperature resistance. Compared with traditional silica-based aerogels, polyimide aerogels have higher mechanical strength and flexibility. Compared with other polymer-based aerogels, polyimide aerogels have obvious advantages in dielectric properties, high and low temperature resistance, chemical corrosion resistance, and radiation resistance. Patent No. CN116606584B discloses a water-based heat-insulating coating and a preparation method thereof. The addition of polyimide aerogel to water-based epoxy resin improves the heat insulation, noise reduction and other properties of the coating, but the compatibility of polyimide aerogel with epoxy resin is poor, which affects the tensile strength and other mechanical properties of the coating. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a heat-insulating metal laminated sheet for building materials and a preparation method thereof, which solves the problem of poor heat insulation effect of metal sheet materials for building materials.

[0005] In one aspect, the present application provides a preparation method of a heat-insulating metal laminated sheet for building materials, which comprises an epoxy resin coating, a PVC film layer, a metal sheet, an ASA film layer, and an epoxy resin coating.

[0006] The preparation method of the epoxy resin coating is as follows:

[0007] Step (1), under a nitrogen atmosphere, mix polyphosphoric acid, 3,3'-diaminobiphenyl diamine, 3,5-dinitrobenzoic acid in a mass ratio of (560-840):100:(198-218), heat to 190-210℃, react for 12-18h, after cooling, dilute with water, add sodium hydroxide solution to adjust pH to 8-9, filter, wash the product with water, dry, then add the product to concentrated hydrochloric acid, gradually add iron powder, and heat to 70-80℃, stir and condense reflux reaction for 6-10h, filter, wash with water, recrystallize the product in ethanol to obtain tetraaminobisbenzimidazole;

[0008] Step (2), add 4,4'-oxydianiline, dianhydride monomer, tetraaminobisbenzimidazole to N-methylpyrrolidone, stir at 20-30℃ for 3-4h under a nitrogen atmosphere, then add acetic anhydride, pyridine, heat to 70-80℃ and stir for 4-6h, then seal and age for 18-24h, add to acetone for replacement for 48-60h, dry the obtained gel material in a supercritical CO2 drying instrument, control the pressure to be 4-8MPa, the temperature to be 40-50℃, and the time to be 4-7h to obtain polyimide aerogel;

[0009] Step (3), mix epoxy resin, toluene solvent, polyimide aerogel, defoaming agent, then add 2-ethyl-4-methylimidazole and stir uniformly to obtain epoxy resin coating, then coat the epoxy resin coating on the surfaces of the PVC film layer and the ASA film layer of the metal plate respectively, and cure to obtain an epoxy resin coating.

[0010] Further, the concentration of the concentrated hydrochloric acid is 30-38%.

[0011] Further, the metal plate is an iron plate, a steel plate or a galvanized plate.

[0012] Further, the mass ratio of the epoxy resin, polyimide aerogel, defoaming agent and 2-ethyl-4-methylimidazole is 100:(4-7):(0.4-0.8):(2-3).

[0013] Further, the curing condition is curing at 110-160℃ for 5-7h.

[0014] Further, the molar ratio of 4,4'-oxydianiline, dianhydride monomer, tetraaminobisbenzimidazole, acetic anhydride and pyridine is (96-98):100:(2-4):(700-850):(700-850).

[0015] Further, the dianhydride monomer is pyromellitic dianhydride or 4,4'-oxydiphthalic dianhydride or 3,3',4,4'-diphenyltetracarboxylic dianhydride.

[0016] Another aspect of the present application provides a heat insulation metal-coated plate for building materials prepared by the above method.

[0017] Beneficial technical effects:

[0018] The present application cross-linking polymerization reaction of the four amino group containing tetraamino bisbenzimidazole, 4, 4'-amino diphenyl ether, dianhydride monomer, get three-dimensional cross-linked network structure of polyimide, and through supercritical CO2 drying treatment, get three-dimensional porous network structure of polyimide aerogel, its specific surface area is larger, pore structure is more abundant, when the hole size is less than the average free path of gas molecules, gas molecules tend to collide with the pore wall, rather than with each other, which greatly reduces the efficiency of energy transfer by collision of gas molecules, improves the thermal insulation performance of aerogel, added to the epoxy coating, it is beneficial to prevent the transfer of heat, reduce the thermal conductivity of coating and metal-coated plate, improve the thermal insulation performance.

[0019] The main chain of the polyimide aerogel of the present application is composed of a large number of aromatic rings with high rigidity, excellent mechanical properties, and contains imidazole groups, which can undergo thermal curing reaction with epoxy resin, thereby improving the interfacial bonding force between the aerogel and the epoxy resin, improving the compatibility of the two, reducing the influence of the aerogel on the mechanical properties of the epoxy resin, and making the epoxy resin maintain good tensile strength and elongation at break. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a structural schematic diagram of the heat insulation metal-coated plate for building materials of the present application. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme of the present application will be described clearly and completely below in combination with specific embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments.

[0022] The model of the epoxy resin of the present application is Phoenix E44. The defoaming agent is Decon 6800.

[0023] Example 1: the preparation method of the heat insulation metal-coated plate for building materials, comprising the following steps:

[0024] Step (1), 70 g of polyphosphoric acid, 12.5 g of 3,3'-diaminobiphenyl diamine, 27.25 g of 3,5-dinitrobenzoic acid were mixed and heated to 190°C for 12 h under a nitrogen atmosphere, after cooling, diluted with water, adjusted to pH 8 with sodium hydroxide solution, the product was washed with water after filtration, dried, then the product was added to 160 mL of 30% concentrated hydrochloric acid, 29 g of iron powder was gradually added, and heated to 80°C, stirred and condensed refluxed for 10 h, filtered, washed with water, the product was recrystallized in ethanol to obtain tetraaminobisbenzimidazole;

[0025] Step (2), 24 mmol of 4,4'-amino diphenyl ether, 25 mmol of pyromellitic anhydride, 1 mmol of tetraaminobisbenzimidazole were added to N-methyl pyrrolidone, stirred at 20°C for 3 h under a nitrogen atmosphere, then 175 mmol of acetic anhydride, 175 mmol of pyridine were added, heated to 80°C and stirred for 4 h, then sealed and aged for 24 h, added to acetone for replacement for 60 h, the obtained gel material was dried in a supercritical CO2 drying instrument, the pressure was controlled at 4 MPa, the temperature was controlled at 40°C, and the time was controlled at 5 h, to obtain a polyimide aerogel;

[0026] Step (3), 200 g of epoxy resin, 40 mL of toluene solvent, 8 g of polyimide aerogel, 1 g of defoaming agent were stirred and mixed, then 30 g of 2-ethyl-4-methyl imidazole was added and stirred uniformly to obtain an epoxy resin coating;

[0027] Step (4), the epoxy resin coating was coated on the surface of the PVC film layer and the ASA film layer of the galvanized sheet respectively, and was cured at 110°C for 1 h, at 140°C for 2 h, and at 160°C for 2 h to form an epoxy resin coating layer, thereby obtaining a heat insulation metal laminated sheet for building materials.

[0028] Example 2: A method for preparing a heat insulation metal laminated sheet for building materials, comprising the following steps:

[0029] Step (1), 70 g of polyphosphoric acid, 12.5 g of 3,3'-diaminobiphenyl diamine, 27.25 g of 3,5-dinitrobenzoic acid were mixed and heated to 190°C for 12 h under a nitrogen atmosphere, after cooling, diluted with water, adjusted to pH 8 with sodium hydroxide solution, the product was washed with water after filtration, dried, then the product was added to 160 mL of 30% concentrated hydrochloric acid, 29 g of iron powder was gradually added, and heated to 80°C, stirred and condensed refluxed for 10 h, filtered, washed with water, the product was recrystallized in ethanol to obtain tetraaminobisbenzimidazole;

[0030] Step (2), 24.6 mmol of 4,4'-aminodiphenyl ether, 25 mmol of 4,4'-oxybisphthalic anhydride, and 0.4 mmol of tetraaminobisbenzimidazole were added to N-methyl pyrrolidone, stirred at 30°C for 4h under nitrogen atmosphere, then 200 mmol of acetic anhydride and 200 mmol of pyridine were added, heated to 70°C and stirred for 6h, then sealed and aged for 18h, added to acetone for displacement for 56h, and the obtained gel material was dried in a supercritical CO2 drying instrument, with the pressure controlled at 8MPa, the temperature at 50°C, and the time at 4h, to obtain a polyimide aerogel;

[0031] Step (3), 200g of epoxy resin, 40mL of toluene solvent, 10g of polyimide aerogel, and 0.8g of defoaming agent were stirred and mixed, then 27g of 2-ethyl-4-methylimidazole was added and stirred uniformly to obtain an epoxy resin coating;

[0032] Step (4), the epoxy resin coating was respectively coated on the surfaces of the PVC film layer and the ASA film layer of the steel plate, and cured at 110°C for 2h, at 140°C for 3h, and at 160°C for 2h to form an epoxy resin coating layer, thereby obtaining a heat insulation metal coated panel for building materials.

[0033] Example 3: tetraaminobisbenzimidazole prepared in Example 1 was used.

[0034] Step (1), 24mmol of 4,4'-aminodiphenyl ether, 25mmol of 3,3',4,4'-biphenyl tetracarboxylic dianhydride, and 1mmol of tetraaminobisbenzimidazole were added to N-methyl pyrrolidone, stirred at 20°C for 3h under nitrogen atmosphere, then 212.5mmol of acetic anhydride and 212.5mmol of pyridine were added, heated to 70°C and stirred for 5h, then sealed and aged for 20h, added to acetone for displacement for 48h, and the obtained gel material was dried in a supercritical CO2 drying instrument, with the pressure controlled at 6MPa, the temperature at 40°C, and the time at 7h, to obtain a polyimide aerogel;

[0035] Step (2), 200g of epoxy resin, 40mL of toluene solvent, 12g of polyimide aerogel, and 1.6g of defoaming agent were stirred and mixed, then 24g of 2-ethyl-4-methylimidazole was added and stirred uniformly to obtain an epoxy resin coating;

[0036] Step (3), the epoxy resin coating was respectively coated on the surfaces of the PVC film layer and the ASA film layer of the iron plate, and cured at 120°C for 2h, at 140°C for 2h, and at 160°C for 2h to form an epoxy resin coating layer, thereby obtaining a heat insulation metal coated panel for building materials.

[0037] Example 4: tetraaminobisbenzimidazole prepared in Example 1 was used.

[0038] Step (1), 24.3 mmol of 4,4'-oxydianiline, 25 mmol of pyromellitic dianhydride, and 0.7 g of tetraaminobisbenzimidazole were added to N-methylpyrrolidone, stirred at 20°C for 3 h under a nitrogen atmosphere, then 210 mmol of acetic anhydride and 210 mmol of pyridine were added, heated to 80°C and stirred for 4 h, then sealed and aged for 24 h, added to acetone and replaced for 48 h, and the obtained gel material was dried in a supercritical CO2 drying instrument, with a pressure of 8 MPa, a temperature of 50°C, and a time of 6 h, to obtain a polyimide aerogel;

[0039] Step (2), 200 g of epoxy resin, 40 mL of toluene solvent, 14 g of polyimide aerogel, and 1.2 g of defoaming agent were stirred and mixed, then 20 g of 2-ethyl-4-methylimidazole was added and stirred uniformly to obtain an epoxy resin coating;

[0040] Step (3), the epoxy resin coating was coated on the surfaces of the PVC film layer and the ASA film layer of the galvanized sheet, respectively, and cured at 110°C for 1 h, at 130°C for 3 h, and at 160°C for 2 h to form an epoxy resin coating layer, thereby obtaining a heat-insulating metal coated sheet for building materials.

[0041] Comparative Example 1: The difference from Example 1 is that no polyimide aerogel is added.

[0042] Step (1), 200 g of epoxy resin, 40 mL of toluene solvent, and 1 g of defoaming agent were stirred and mixed, then 30 g of 2-ethyl-4-methylimidazole was added and stirred uniformly to obtain an epoxy resin coating;

[0043] Step (2), the epoxy resin coating was coated on the surfaces of the PVC film layer and the ASA film layer of the galvanized sheet, respectively, and cured at 110°C for 1 h, at 140°C for 2 h, and at 160°C for 2 h to form an epoxy resin coating layer, thereby obtaining a heat-insulating metal coated sheet for building materials.

[0044] Comparative Example 2: The difference from Example 1 is that no tetraaminobisbenzimidazole is added.

[0045] Step (1), 24 mmol of 4,4'-oxydianiline and 25 mmol of pyromellitic dianhydride were added to N-methylpyrrolidone, stirred at 20°C for 3 h under a nitrogen atmosphere, then 175 mmol of acetic anhydride and 175 mmol of pyridine were added, heated to 80°C and stirred for 4 h, then sealed and aged for 24 h, added to acetone and replaced for 60 h, and the obtained gel material was dried in a supercritical CO2 drying instrument, with a pressure of 4 MPa, a temperature of 40°C, and a time of 5 h, to obtain a polyimide aerogel;

[0046] Step (2), 200 g of epoxy resin, 40 mL of toluene solvent, 8 g of polyimide aerogel, 1 g of defoaming agent were stirred and mixed, then 30 g of 2-ethyl-4-methylimidazole was added and stirred uniformly to obtain an epoxy resin coating;

[0047] Step (3), the epoxy resin coating was coated on the surface of the PVC film layer and the ASA film layer of the galvanized sheet respectively, and was cured at 110°C for 1 h, at 140°C for 2 h, and at 160°C for 2 h to form an epoxy resin coating layer, thereby obtaining a heat insulation metal laminated sheet for building materials.

[0048] Comparative Example 3: The difference from Example 1 is that 3,3'-diaminobenzidine is used instead of tetraaminobisbenzimidazole.

[0049] Step (1), 24 mmol of 4,4'-oxydianiline, 25 mmol of pyromellitic anhydride, and 1 mmol of 3,3'-diaminobenzidine were added to N-methylpyrrolidone, stirred at 20°C under a nitrogen atmosphere for 3 h, then 175 mmol of acetic anhydride and 175 mmol of pyridine were added, heated to 80°C and stirred for 4 h, then sealed and aged for 24 h, added to acetone and replaced for 60 h, and the obtained gel material was dried in a supercritical CO2 drying instrument, with a pressure of 4 MPa, a temperature of 40°C, and a time of 5 h, to obtain polyimide aerogel;

[0050] Step (2), 200 g of epoxy resin, 40 mL of toluene solvent, 8 g of polyimide aerogel, 1 g of defoaming agent were stirred and mixed, then 30 g of 2-ethyl-4-methylimidazole was added and stirred uniformly to obtain an epoxy resin coating;

[0051] Step (3), the epoxy resin coating was coated on the surface of the PVC film layer and the ASA film layer of the galvanized sheet respectively, and was cured at 110°C for 1 h, at 140°C for 2 h, and at 160°C for 2 h to form an epoxy resin coating layer, thereby obtaining a heat insulation metal laminated sheet for building materials.

[0052] Comparative Example 4: The difference from Example 1 is that 2-(4-aminophenyl)-5-aminobenzimidazole (CAS No. 7621-86-5) is used instead of tetraaminobisbenzimidazole.

[0053] Step (1), 24 mmol of 4,4'-aminodiphenyl ether, 25 mmol of pyromellitic anhydride, 1 mmol of 2-(4-aminophenyl)-5-aminobenzimidazole were added to N-methyl pyrrolidone, stirred at 20℃ for 3h under nitrogen atmosphere, then 175 mmol of acetic anhydride and 175 mmol of pyridine were added, heated to 80℃ and stirred for 4h, then sealed and aged for 24h, then replaced in acetone for 60h, the obtained gel material was dried in a supercritical CO2 drying instrument, the pressure was controlled at 4MPa, the temperature was controlled at 40℃, and the time was controlled at 5h, to obtain polyimide aerogel;

[0054] Step (2), 200g of epoxy resin, 40mL of toluene solvent, 8g of polyimide aerogel, and 1g of defoaming agent were stirred and mixed, then 30g of 2-ethyl-4-methylimidazole was added and stirred uniformly to obtain an epoxy resin coating;

[0055] Step (3), the epoxy resin coating was coated on the surface of the PVC film layer and the ASA film layer of the galvanized sheet respectively, and cured at 110℃ for 1h, at 140℃ for 2h, and at 160℃ for 2h to form an epoxy resin coating layer, thereby obtaining a heat insulation metal coated panel for building materials.

[0056] The specific surface area and pore size analyzer was used to measure the specific surface area of the polyimide aerogel.

[0057] The thermal conductivity of the epoxy resin coating was tested according to the method of GB / T 10294-2008.

[0058] The epoxy resin coating prepared in each example and comparative example was poured into a mold and heat-cured to prepare a test sample, and the tensile properties were tested according to the method of GB / T 1040.1-2018.

[0059] Table 1: Performance test results of each example and comparative example

[0060]

[0061] As can be seen from the data in Table 1, each embodiment crosslinks and polymerizes the four-amino-bis-benzimidazole containing multiple amino groups with 4,4'-amino diphenyl ether and dianhydride monomers to obtain polyimide with a three-dimensional crosslinked network structure, and through supercritical CO2 drying treatment, polyimide aerogel with a three-dimensional porous network structure is obtained, which has a larger specific surface area and a more abundant pore structure, and when added to an epoxy resin coating, it is beneficial to prevent the transfer of heat, reduce the thermal conductivity of the coating and metal clad plate, and improve the heat preservation and insulation performance. And the polyimide aerogel contains imidazole groups, which can undergo thermal curing reaction with the epoxy resin, thereby improving the interfacial bonding force between the aerogel and the epoxy resin, improving the compatibility of the two, reducing the influence of the aerogel on the mechanical properties of the epoxy resin, and making the epoxy resin maintain good tensile strength and elongation at break.

[0062] As can be seen from the data in Table 1, the epoxy resin coating of Comparative Example 1 does not add polyimide aerogel, resulting in a larger thermal conductivity of the coating, which is not conducive to improving the heat preservation and insulation performance of the coating and metal clad plate.

[0063] The polyimide aerogel prepared in Comparative Example 2 and Comparative Example 3 does not contain imidazole groups and cannot undergo thermal curing reaction with the epoxy resin, does not improve the interfacial bonding force between the aerogel and the epoxy resin, and affects the mechanical properties of the epoxy resin, resulting in lower tensile strength and elongation at break of the epoxy resin. And the polyimide aerogel prepared in Comparative Example 2 does not add a crosslinking agent, resulting in a lower specific surface area and fewer pore structures, which is not conducive to reducing the thermal conductivity of the epoxy resin coating and affecting the heat preservation and insulation performance of the coating and metal clad plate.

[0064] Comparative Example 4 uses 2-(4-aminophenyl)-5-aminobenzimidazole instead of four-amino-bis-benzimidazole to prepare polyimide aerogel, and 2-(4-aminophenyl)-5-aminobenzimidazole contains only two amino groups, which cannot undergo crosslinking reaction, making it difficult to obtain polyimide with a three-dimensional crosslinked network structure, resulting in a smaller specific surface area and fewer pore structures of the aerogel, which is not conducive to reducing the thermal conductivity of the epoxy resin coating and affecting the heat preservation and insulation performance of the coating and metal clad plate.

[0065] The above-described embodiments only express the embodiments of the present application, which are described in detail and specifically, but should not be construed as limiting the scope of the present patent. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of improvements can be made, which are within the scope of protection of the present application.

Claims

1. A method for preparing heat-insulating metal-coated panels for building materials, characterized in that, The heat-insulating metal clad panel is composed of: an epoxy resin coating, a PVC film layer, a metal plate, an ASA film layer, and an epoxy resin coating. The epoxy resin coating is prepared by: Step (1): Add 4,4'-aminodiphenyl ether, dianhydride monomer, and tetraaminobisbenzimidazole to N-methylpyrrolidone. Stir and react at 20-30℃ for 3-4 hours under a nitrogen atmosphere. Then add acetic anhydride and pyridine, heat to 70-80℃ and stir and react for 4-6 hours. Then seal and age for 18-24 hours. Add acetone for displacement for 48-60 hours. The resulting gel material is dried in a supercritical CO2 dryer at a pressure of 4-8 MPa, a temperature of 40-50℃ and a time of 4-7 hours to obtain polyimide aerogel. Step (2): Stir and mix epoxy resin, toluene solvent, polyimide aerogel and defoamer, then add 2-ethyl-4-methylimidazole and stir evenly to obtain epoxy resin coating. Then coat the epoxy resin coating onto the PVC film layer and ASA film layer of the metal plate respectively and cure to obtain epoxy resin coating. The preparation method of the tetraaminobisbenzimidazole is as follows: under a nitrogen atmosphere, polyphosphoric acid, 3,3'-diaminobenzidine and 3,5-dinitrobenzoic acid are mixed and heated to 190-210℃ for 12-18h. After cooling, water is added for dilution, sodium hydroxide solution is added to adjust the pH to 8-9, the product is filtered, washed with water and dried, and then the product is added to concentrated hydrochloric acid, iron powder is gradually added, and the mixture is heated to 70-80℃, stirred and refluxed for 6-10h, filtered, washed with water, and the product is recrystallized in ethanol to obtain tetraaminobisbenzimidazole. The mass ratio of the polyphosphoric acid, 3,3'-diaminobenzidine, and 3,5-dinitrobenzoic acid is (560-840):100:(198-218).

2. The method for preparing a heat-insulating metal-coated panel for building materials according to claim 1, characterized in that, The metal plate is an iron plate, steel plate, or galvanized plate.

3. The method for preparing a heat-insulating metal-coated panel for building materials according to claim 1, characterized in that, The mass ratio of the epoxy resin, polyimide aerogel, defoamer, and 2-ethyl-4-methylimidazole is 100:(4-7):(0.4-0.8):(2-3).

4. The method for preparing a heat-insulating metal-coated panel for building materials according to claim 1, characterized in that, The curing conditions are 110-160℃ for 5-7 hours.

5. The method for preparing a heat-insulating metal-coated panel for building materials according to claim 1, characterized in that, The molar ratio of 4,4'-aminodiphenyl ether, dianhydride monomer, tetraaminobisbenzimidazole, acetic anhydride, and pyridine is (96-98):100:(2-4):(700-850):(700-850).

6. The method for preparing a heat-insulating metal-coated panel for building materials according to claim 1, characterized in that, The dianhydride monomer is pyromellitic anhydride, 4,4'-oxobisphthalic anhydride, or 3,3',4,4'-biphenyltetracarboxylic acid dianhydride.

7. The method for preparing a heat-insulating metal-coated panel for building materials according to claim 1, characterized in that, The concentration of the concentrated hydrochloric acid is 30-38%.

8. The heat-insulating metal-coated panel for building materials obtained by the preparation method according to any one of claims 1-7.

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