Preparation method and application of inorganic mixture coating for protecting metal roof

Abstract

This invention belongs to the field of metal anti-corrosion coating manufacturing technology, specifically relating to a method for preparing and applying an inorganic mixture coating for protecting metal roofs. This invention introduces silicate cement into the coating; the solidified silicate and acrylic acid form a three-dimensional composite network. Shell powder provides a lightweight skeleton and reaction sites for the hydrolysis loading of titanium dioxide. Bentonite and mica vermiculite form a multi-layered structure that can form a directional arrangement within the coating to shield ultraviolet rays and effectively block heat conduction. Acrylic polysiloxane coating improves the compatibility of fillers in water-based silicone-acrylic emulsions. During film formation, the silicone-acrylic emulsion containing siloxane segments tends to migrate to the coating surface, forming a silicon-rich surface protective layer, improving the weather resistance of the protective coating and preventing chalking and peeling caused by interfacial degradation.

Description

Technical Field

[0001] This invention belongs to the field of metal anti-corrosion coating manufacturing technology, specifically relating to a method for preparing and applying an inorganic mixture coating for protecting metal roofs. Background Technology

[0002] Metal roofs are lightweight, aesthetically pleasing, and easy to install, making them popular in both residential and industrial buildings. However, due to their exposure to the outdoors, metal roofs are susceptible to corrosion from ultraviolet radiation, large temperature differences, and rainwater, leading to rust and eventual failure. Currently, the common method for protecting metal roofs is to apply a protective coating. Acrylic paint is one of the most widely used anti-corrosion coatings. However, traditional acrylic anti-corrosion coatings suffer from drawbacks: thin application thickness leads to cracking, peeling, and sagging; and their UV resistance is insufficient when exposed to sunlight. Consequently, metal roofs renovated with acrylic anti-corrosion coatings often experience rust and discoloration within three to four years, requiring further repairs.

[0003] Chinese invention patent CN119752299B discloses a high-temperature resistant metal coating and its preparation process. In this invention, intermediate A is first prepared using acrylic acid and 1,1,3,3-tetramethyldisiloxane as raw materials. Intermediate B is obtained by reacting diethanolamine, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and paraformaldehyde. Intermediate A and intermediate B are reacted in a molar ratio of 1:2 to obtain a silicon-containing flame-retardant diol. Then, polytetrahydrofuran ether diol 2000 and the silicon-containing flame-retardant diol are mixed and reacted with isophorone diisocyanate to extend the chain and obtain a modified polyurethane emulsion. Finally, the modified polyurethane emulsion, deionized water, wetting agent, defoamer, dispersant, titanium dioxide, barium sulfate powder, zinc phosphate, leveling agent, and thickener are mixed and stirred to obtain the high-temperature resistant metal coating. However, existing technologies suffer from the drawbacks of traditional acrylic emulsion color steel water-based paint products, such as poor sun resistance and the limitation of thin coatings, resulting in a short lifespan. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing and applying an inorganic mixture coating for protecting metal roofs, which solves the technical problem of short lifespan caused by the shortcomings of traditional acrylic emulsion color steel water-based paint products in the prior art, such as poor sun resistance and the fact that they can only be applied in thin layers.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: An inorganic mixture coating for protecting metal roofs is divided into component A and component B; Component A is prepared from the following raw materials in parts by weight: 30-50 parts weather-resistant filler, 10-15 parts quartz sand, 5-10 parts quartz powder, 10-15 parts silicate cement and 10-20 parts inorganic color powder; Component B is prepared from the following raw materials in parts by weight: 100 parts of water-based silicone-acrylic emulsion, 5-8 parts of film-forming aid, 10-15 parts of rust inhibitor, 0.5-2 parts of silicone defoamer, 0.5-2 parts of leveling agent and 0.5-2 parts of wetting agent; The average particle size of the quartz sand is 60~70μm, and the average particle size of the quartz powder is 18~25μm; The film-forming aid is any one or a combination of ethylene glycol butyl ether, dipropylene glycol methyl ether, and dodecyl alcohol ester; The inorganic pigment is any one or a combination of iron oxide black powder, iron oxide red powder, and titanium dioxide; The rust inhibitor is prepared by mixing zinc powder, zinc phosphate and strontium chromium yellow in a mass ratio of 8~10:3~5:1~2, and the average particle size of the zinc powder is 5~10μm.

[0006] A method for preparing an inorganic mixture coating for protecting metal roofs includes the following steps: S1. Add the raw materials of component B to the mixer in sequence, add component A while stirring, speed up the stirring and dispersion to obtain a slurry; S2. Filter the slurry to remove large particles, and let it stand at room temperature to mature, thus obtaining an inorganic mixture coating for protecting metal roofs.

[0007] Preferably, in step S1, component B is stirred and mixed at a speed of 300-500 rpm for 20-30 minutes, and after adding component A, it is stirred at a speed of 1000-2000 rpm for 20-30 minutes. The amount of component B is 20-35% of the mass of component A.

[0008] Preferably, the S2 is passed through a 300-mesh sieve and left to stand at room temperature for 1-2 hours to mature.

[0009] Preferably, the preparation method of the weather-resistant filler includes the following steps: S11. Soak and clean the seashells in an aqueous sodium hydroxide solution, wash with deionized water, dry, grind in a grinder, and calcine to obtain light calcium powder. S12. Add light calcium powder to ethanol, add tetrabutyl titanate dropwise, heat to modify, filter to collect solid, wash, dry and grind to obtain modified light calcium powder. S13. Modified light calcium powder, bentonite and mica vermiculite are mixed to obtain a mixture, which is then added to deionized water. Acrylic polysiloxane is added and heated under stirring to modify the mixture. The solid is collected by filtration and dried to obtain a weather-resistant filler.

[0010] Preferably, the concentration of the sodium hydroxide aqueous solution in S11 is 40~60g / L, soaked for 24~48h, dried at 80~100℃, ground to an average particle size of 18~25μm, and calcined at 300~500℃ for 1~2h.

[0011] Preferably, the mass ratio of light calcium powder, ethanol and tetrabutyl titanate in S12 is 10~15:100:3~5. The mixture is heated to 40~60℃ for 1~2 hours, washed with deionized water, dried at 70~80℃, and ground until the passing rate through a 200~300 mesh sieve is greater than 90%.

[0012] Preferably, in step S13, the mass ratio of modified light calcium powder, bentonite, and mica vermiculite is 3~5:1~2:10~15, and the mixture is stirred at 300~500 rpm for 1~2 hours. The mass ratio of the mixture, deionized water, and acrylic polysiloxane is 30~35:100:0.5~2. The mixture is heated to 50~60℃ for 1~2 hours and then dried at 70~80℃.

[0013] Preferably, the method for preparing the aqueous silicone-acrylic emulsion includes the following steps: S21. Add deionized water and emulsifier to a reaction vessel and stir to emulsify. Add KH-570 and KH-802 and heat to react. After cooling to room temperature, add deionized water to dilute and obtain a silicone-based emulsion. S22. Acrylic acid, hydroxyethyl acrylate, butyl acrylate, methacrylic acid and methyl methacrylate are added to a silicone-based emulsion, and azobisisobutyronitrile initiator is added dropwise and the mixture is heated to obtain a mixture. After cooling the mixture, ammonia water is added to neutralize it to obtain an aqueous silicone-acrylic emulsion.

[0014] Preferably, the emulsifier in S21 is prepared by mixing sodium dodecyl sulfate and dodecyl alcohol polyoxyethylene ether in a mass ratio of 1:1~2, homogenizing at a speed of 1000~2000 rpm for 5~10 min, and the mass ratio of deionized water, emulsifier, KH-570 and KH-802 is 100~110:2~5:10~15:3~5. The mixture is heated to 50~60℃ and reacted for 4~6 h, and then diluted with deionized water to a solid content of 8~10 wt%.

[0015] Preferably, in S22, the mass ratio of acrylic acid, hydroxyethyl acrylate, butyl acrylate, methacrylic acid, methyl methacrylate, silicone emulsion and azobisisobutyronitrile initiator is 3~5:8~10:13~16:4~6:15~18:100:1~4, and the reaction is carried out at 80~85℃ for 4~6 hours.

[0016] An inorganic mixture coating preparation method for protecting metal roofs is disclosed. The coating is used to prepare a protective coating for metal roofs. The stainless steel metal roof surface is cleaned with a high-pressure water gun and dried completely. The coating is then sprayed onto the surface at an output pressure of 15-25 MPa and a spraying speed of 20-40 m / min. The surface is dried at room temperature and cured for 1-3 days to obtain a protective coating for metal roofs with an average thickness of 250-350 μm.

[0017] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. This invention involves the hydrothermal polymerization of tetrabutyl titanate to form titanium dioxide, which is then loaded onto the surface of shell powder. This mixture is then combined with bentonite and mica vermiculite, and finally coated with acrylic polysiloxane to obtain a weather-resistant filler. The introduction of titanium dioxide improves the UV resistance of the shell powder, while the shell powder provides a lightweight framework and reaction sites for the hydrolysis loading of titanium dioxide. The bentonite and mica vermiculite have a multi-layered structure that can form a directional arrangement in the coating to shield ultraviolet rays and effectively block heat conduction. The acrylic polysiloxane coating improves the compatibility of the filler in the water-based silicone-acrylic emulsion, making the weather-resistant filler resistant to aging, with a high coating rate, and preventing the powdering and peeling of the protective coating due to interfacial degradation.

[0018] 2. This invention uses KH-570 and KH-802 to hydrolyze and polymerize a silicone-based emulsion, and then grafts acrylic acid monomers to obtain an aqueous silicone-acrylic emulsion. KH-570 provides double bonds and hydrolyzable methoxysilanes as a silicone-based framework, and KH-802 is polymerized to form a silicone-based seed core with phenyl groups, which improves the impact resistance of the coating. Hydroxyethyl acrylate provides hydrophilic properties, and acrylic acid and methacrylic acid can thicken the emulsion and improve the adhesion to the metal substrate, so that the prepared aqueous silicone-acrylic emulsion has excellent adhesion.

[0019] 3. The coating prepared by this invention has a solid content of more than 80 wt%, and leaves fewer pores after the water evaporates, which can form a denser and more complete continuous coating film. The introduction of silicate cement into the coating allows the solidified silicate to form a three-dimensional composite network with acrylic acid. During the film formation process, the silicone-acrylic emulsion containing siloxane segments tends to migrate to the coating surface to form a silicon-rich surface protective layer, which improves the weather resistance of the protective coating. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] The acrylic polysiloxane involved in this invention is model BXS-90, the silicate cement is model P·W 42.5, the organosilicon defoamer is model HY-2248, the leveling agent is model BYK-346, and the wetting agent is model Tego245.

[0022] Example 1: The inorganic mixture coating for protecting metal roofs in this example is divided into component A and component B; Component A is made from the following raw materials: 30 kg of weather-resistant filler, 10 kg of quartz sand, 5 kg of quartz powder, 10 kg of silicate cement and 20 kg of inorganic color powder. Component B is prepared from the following raw materials: 100 kg of water-based silicone-acrylic emulsion, 5 kg of film-forming aid, 10 kg of rust inhibitor, 0.5 kg of silicone defoamer, 0.5 kg of leveling agent and 0.5 kg of wetting agent; The average particle size of the quartz sand is 70 μm, and the average particle size of the quartz powder is 18 μm. The film-forming aid is prepared by mixing ethylene glycol butyl ether and dipropylene glycol methyl ether in a mass ratio of 1:1. The inorganic color powder is prepared by mixing iron oxide black powder and iron oxide red powder in a mass ratio of 1:2. The rust inhibitor is prepared by mixing zinc powder, zinc phosphate and strontium chromium yellow in a mass ratio of 8.5:3:1.5, and the average particle size of the zinc powder is 7μm.

[0023] This embodiment describes a method for preparing an inorganic mixture coating for protecting metal roofs, comprising the following steps: S1. Add 20kg of component B raw material to the mixer in sequence and mix at 500rpm for 30min. Add 100kg of component A and increase the speed to 2000rpm for 20min to obtain slurry. S2. The slurry is filtered through a 300-mesh sieve to remove large particles, and then allowed to stand at room temperature for 1 hour to mature, thus obtaining an inorganic mixture coating for protecting metal roofs.

[0024] The method for preparing the weather-resistant filler in this embodiment includes the following steps: S11. Soak and wash 10 kg of seashells in a 40 g / L sodium hydroxide aqueous solution for 24 h, wash with deionized water, dry at 80 °C, grind in a grinder until the average particle size is 18 μm, and calcine at 300 °C for 1 h to obtain light calcium powder. S12. Add 5 kg of light calcium powder to 50 kg of ethanol, add 1.7 kg of tetrabutyl titanate, heat to 60℃ for 2 h, filter to collect solid, wash, dry at 80℃ and grind until the passing rate of 300 mesh sieve is greater than 90% to obtain modified light calcium powder. S13. Mix 6 kg of modified light calcium powder, 4 kg of bentonite and 20 kg of mica vermiculite at 300 rpm for 2 hours to obtain a mixture. Then add 100 kg of deionized water and 1 kg of acrylic polysiloxane. Stir at 500 rpm and heat to 60℃ for 2 hours. Filter to collect the solid and dry at 70℃ to obtain the weather-resistant filler.

[0025] The method for preparing the aqueous silicone-acrylic emulsion in this embodiment includes the following steps: S21. Add 100 kg of deionized water and 5 kg of emulsifier prepared by mixing sodium dodecyl sulfate and dodecyl alcohol polyoxyethylene ether in a mass ratio of 1:1 into a reaction vessel and emulsify at 1000 rpm for 5 min. Add 13 kg of KH-570 and 3 kg of KH-802 and heat to 60℃ for 6 h. After cooling to room temperature, add deionized water to dilute to a solid content of 10 wt% to obtain a silicone-based emulsion. S22. Add 3 kg of acrylic acid, 8 kg of hydroxyethyl acrylate, 14 kg of butyl acrylate, 5 kg of methacrylic acid and 15 kg of methyl methacrylate to 100 kg of silicone emulsion, add 2 kg of azobisisobutyronitrile initiator dropwise, heat to 80°C and react for 4 h to obtain a mixture. After cooling the mixture, add ammonia water to neutralize it to obtain an aqueous silicone-acrylic emulsion.

[0026] The application of the inorganic mixture coating preparation method for protecting metal roofs in this embodiment is to prepare a protective coating for metal roofs. The stainless steel metal roof surface is cleaned with a high-pressure water gun and dried completely. The coating is then sprayed onto the surface at an output pressure of 15 MPa and a spraying speed of 20 m / min. After drying at room temperature and curing for 3 days, a protective coating for metal roofs with an average thickness of 250 μm is obtained.

[0027] Example 2: The inorganic mixture coating for protecting metal roofs in this example is divided into component A and component B; Component A is made from the following raw materials: 40 kg of weather-resistant filler, 10 kg of quartz sand, 10 kg of quartz powder, 15 kg of silicate cement and 10 kg of inorganic color powder. Component B is prepared from the following raw materials: 100 kg of water-based silicone-acrylic emulsion, 7 kg of film-forming aid, 13 kg of rust inhibitor, 1 kg of silicone defoamer, 2 kg of leveling agent and 2 kg of wetting agent. The average particle size of the quartz sand is 60 μm, and the average particle size of the quartz powder is 25 μm; The film-forming aid is dodecyl alcohol ester; The inorganic color powder is prepared by mixing iron oxide red powder and titanium dioxide in a mass ratio of 3:1. The rust inhibitor is prepared by mixing zinc powder, zinc phosphate and strontium chromium yellow in a mass ratio of 10:5:1.5, and the average particle size of the zinc powder is 5μm.

[0028] This embodiment describes a method for preparing an inorganic mixture coating for protecting metal roofs, comprising the following steps: S1. Add 30kg of component B raw material to the mixer in sequence and mix at 500rpm for 20min. Add 100kg of component A and increase the speed to 2000rpm for 30min to obtain slurry. S2. The slurry is filtered through a 300-mesh sieve to remove large particles, and then allowed to stand at room temperature for 2 hours to mature, thus obtaining an inorganic mixture coating for protecting metal roofs.

[0029] The method for preparing the weather-resistant filler in this embodiment includes the following steps: S11. Soak and wash 15 kg of seashells in a 50 g / L sodium hydroxide aqueous solution for 48 h, wash with deionized water, dry at 100 °C, grind in a grinder until the average particle size is 25 μm, and calcine at 400 °C for 2 h to obtain light calcium powder. S12. Add 7.5 kg of light calcium powder to 50 kg of ethanol, add 2 kg of tetrabutyl titanate, heat to 50 °C for 2 h, filter to collect solid, wash, dry at 80 °C and grind until the passing rate of 300 mesh sieve is greater than 90% to obtain modified light calcium powder. S13. 7 kg of modified light calcium powder, 3 kg of bentonite and 25 kg of mica vermiculite were mixed at 300-500 rpm for 1.5 h to obtain a mixture. Then, 110 kg of deionized water and 1.5 kg of acrylic polysiloxane were added and stirred at 600 rpm. The mixture was heated to 60℃ for 1 h for modification. The solid was collected by filtration and dried at 70℃ to obtain the weather-resistant filler.

[0030] The method for preparing the aqueous silicone-acrylic emulsion in this embodiment includes the following steps: S21. Add 105 kg of deionized water and 3 kg of emulsifier prepared by mixing sodium dodecyl sulfate and dodecyl alcohol polyoxyethylene ether at a mass ratio of 1:1.5 into a reaction vessel and emulsify at 2000 rpm for 10 min. Add 10 kg of KH-570 and 5 kg of KH-802 and heat to 50°C and react for 4 h. After cooling to room temperature, add deionized water to dilute to a solid content of 8 wt% to obtain a silicone-based emulsion. S22. Add 4.5 kg of acrylic acid, 10 kg of hydroxyethyl acrylate, 14.5 kg of butyl acrylate, 4.5 kg of methacrylic acid and 16.5 kg of methyl methacrylate to 100 kg of silicone emulsion, add 1 kg of azobisisobutyronitrile initiator dropwise, heat to 80°C and react for 6 h to obtain a mixture. After cooling the mixture, add ammonia water to neutralize it to obtain an aqueous silicone-acrylic emulsion.

[0031] The application of the inorganic mixture coating preparation method for protecting metal roofs in this embodiment is to prepare a protective coating for metal roofs. The stainless steel metal roof surface is cleaned with a high-pressure water gun and dried completely. The coating is then sprayed onto the surface at an output pressure of 25 MPa and a spraying speed of 40 m / min. After drying at room temperature and curing for 1 day, a protective coating for metal roofs with an average thickness of 350 μm is obtained.

[0032] Example 3: The inorganic mixture coating for protecting metal roofs in this example is divided into component A and component B; Component A is made from the following raw materials: 50 kg of weather-resistant filler, 14 kg of quartz sand, 7 kg of quartz powder, 12 kg of silicate cement and 17 kg of inorganic color powder. Component B is prepared from the following raw materials: 100 kg of water-based silicone-acrylic emulsion, 8 kg of film-forming aid, 15 kg of rust inhibitor, 2 kg of silicone defoamer, 1 kg of leveling agent and 2 kg of wetting agent. The average particle size of the quartz sand is 64 μm, and the average particle size of the quartz powder is 24 μm; The film-forming aid is prepared by mixing ethylene glycol butyl ether and dipropylene glycol methyl ether in a mass ratio of 2:1. The inorganic color powder is prepared by mixing iron oxide black powder, iron oxide red powder and titanium dioxide in a mass ratio of 1:3:1; The rust inhibitor is prepared by mixing zinc powder, zinc phosphate and strontium chromium yellow in a mass ratio of 9:4:2, and the average particle size of the zinc powder is 10 μm.

[0033] This embodiment describes a method for preparing an inorganic mixture coating for protecting metal roofs, comprising the following steps: S1. Add 35kg of component B raw material to the mixer in sequence and mix at 300rpm for 20min. Add 100kg of component A and increase the speed to 2000rpm for 30min to obtain slurry. S2. The slurry is filtered through a 300-mesh sieve to remove large particles, and then allowed to stand at room temperature for 2 hours to mature, thus obtaining an inorganic mixture coating for protecting metal roofs.

[0034] The method for preparing the weather-resistant filler in this embodiment includes the following steps: S11. Soak and wash 15 kg of seashells in a 60 g / L sodium hydroxide aqueous solution for 48 h, wash with deionized water, dry at 100 °C, grind in a grinder until the average particle size is 24 μm, and calcine at 500 °C for 2 h to obtain light calcium powder. S12. Add 7.5 kg of light calcium powder to 50 kg of ethanol, add 2.5 kg of tetrabutyl titanate dropwise, heat to 60℃ for 2 h, filter to collect solid, wash, dry at 80℃ and grind until the passing rate of 200 mesh sieve is greater than 90% to obtain modified light calcium powder. S13. Mix 10 kg of modified light calcium powder, 4 kg of bentonite and 30 kg of mica vermiculite at 500 rpm for 2 hours to obtain a mixture. Then add 130 kg of deionized water and 2.5 kg of acrylic polysiloxane. Stir at 800 rpm and heat to 60℃ for 2 hours. Filter to collect the solid and dry at 80℃ to obtain the weather-resistant filler.

[0035] The method for preparing the aqueous silicone-acrylic emulsion in this embodiment includes the following steps: S21. Add 110 kg of deionized water and 5 kg of emulsifier prepared by mixing sodium dodecyl sulfate and dodecyl alcohol polyoxyethylene ether at a mass ratio of 1:2 into a reaction vessel and emulsify at 2000 rpm for 10 min. Add 15 kg of KH-570 and 5 kg of KH-802 and heat to 60℃ for 6 h. After cooling to room temperature, add deionized water to dilute to a solid content of 9 wt% to obtain a silicone-based emulsion. S22. Add 5 kg of acrylic acid, 9 kg of hydroxyethyl acrylate, 16 kg of butyl acrylate, 6 kg of methacrylic acid and 18 kg of methyl methacrylate to 100 kg of silicone emulsion, add 4 kg of azobisisobutyronitrile initiator dropwise, heat to 85°C and react for 6 h to obtain a mixture. After cooling the mixture, add ammonia water to neutralize it to obtain an aqueous silicone-acrylic emulsion.

[0036] The application of the inorganic mixture coating preparation method for protecting metal roofs in this embodiment is to prepare a protective coating for metal roofs. The stainless steel metal roof surface is cleaned with a high-pressure water gun and dried completely. The coating is then sprayed onto the surface at an output pressure of 20 MPa and a spraying speed of 30 m / min. After drying at room temperature and curing for 2 days, a protective coating for metal roofs with an average thickness of 300 μm is obtained.

[0037] Comparative Example 1 differs from Example 1 in that the weather-resistant filler is replaced with heavy calcium carbonate powder with an average particle size of 30 μm.

[0038] Comparative Example 2 differs from Example 1 in that the aqueous silicone-acrylic emulsion is replaced with an acrylic emulsion of model FA120.

[0039] Comparative Example 3 differs from Example 1 in that the average thickness of the protective coating obtained is 50 μm.

[0040] Performance testing The adhesion of the protective coatings prepared in each example and comparative example was measured according to GB / T 5210-2006 "Paints and Varnishes - Pull-off Adhesion Test".

[0041] According to GB / T 16777-2008 "Test Methods for Waterproof Coatings for Buildings", the pressure of the protective coatings prepared in each example and comparative example on the back side of the mortar test block resisting the penetration of pressurized water was measured.

[0042] According to GB / T 18244-2022 "Aging Test Method for Building Waterproofing Materials", the protective coatings prepared in each embodiment and comparative example were placed under an irradiance of 0.68 W / (m²). 2 The protective coating was irradiated for 2000 hours under a UV lamp with a relative humidity of 50% (×nm) and the surface condition was observed.

[0043] The test results are shown in Table 1 below: Table 1 Test Results

[0044] As shown in Table 1, the adhesion of the protective coatings prepared in Examples 1-3 is 1.01-1.10 MPa, and the pressure resistance to water penetration is 0.85-0.86 MPa. This indicates that the inorganic mixture coating prepared by the present invention has good adhesion to stainless steel and can prevent water penetration to the interface between the coating and the stainless steel. The protective coatings prepared in Examples 1-3 showed no cracks after 2000 hours of irradiation under ultraviolet light, indicating that the protective coating prepared by the present invention has excellent weather resistance.

[0045] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0046] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. An inorganic mixture coating for protecting metal roofs, characterized in that, It consists of component A and component B; Component A is prepared from the following raw materials in parts by weight: 30-50 parts weather-resistant filler, 10-15 parts quartz sand, 5-10 parts quartz powder, 10-15 parts silicate cement and 10-20 parts inorganic color powder; Component B is prepared from the following raw materials in parts by weight: 100 parts of water-based silicone-acrylic emulsion, 5-8 parts of film-forming aid, 10-15 parts of rust inhibitor, 0.5-2 parts of organosilicon defoamer, 0.5-2 parts of leveling agent and 0.5-2 parts of wetting agent.

2. The inorganic mixture coating for protecting metal roofs according to claim 1, characterized in that, The average particle size of the quartz sand is 60-70 μm, and the average particle size of the quartz powder is 18-25 μm; the film-forming aid is any one or a combination of ethylene glycol butyl ether, dipropylene glycol methyl ether, and dodecyl alcohol ester; the inorganic color powder is any one or a combination of iron oxide black powder, iron oxide red powder, and titanium dioxide; the rust inhibitor is prepared by mixing zinc powder, zinc phosphate, and strontium chrome yellow in a mass ratio of 8-10:3-5:1-2, and the average particle size of the zinc powder is 5-10 μm.

3. The inorganic mixture coating for protecting metal roofs according to claim 1, characterized in that, The preparation method of the weather-resistant filler includes the following steps: S11. Soak and clean the seashells in an aqueous sodium hydroxide solution, wash with deionized water, dry, grind in a grinder, and calcine to obtain light calcium powder. S12. Add light calcium powder to ethanol, add tetrabutyl titanate dropwise, heat to modify, filter to collect solid, wash, dry and grind to obtain modified light calcium powder. S13. Modified light calcium powder, bentonite and mica vermiculite are mixed to obtain a mixture, which is then added to deionized water. Acrylic polysiloxane is added and heated under stirring to modify the mixture. The solid is collected by filtration and dried to obtain a weather-resistant filler.

4. The inorganic mixture coating for protecting metal roofs according to claim 3, characterized in that, In S11, the concentration of the sodium hydroxide aqueous solution is 40-60 g / L. The solution is soaked for 24-48 hours, dried at 80-100℃, ground to an average particle size of 18-25 μm, and calcined at 300-500℃ for 1-2 hours. In S12, the mass ratio of light calcium powder, ethanol, and tetrabutyl titanate is 10-15:100:3-5. The solution is modified at 40-60℃ for 1-2 hours, dried at 70-80℃, and ground to an average particle size of 18-25 μm. The pass rate through a 200-300 mesh sieve is greater than 90%; the mass ratio of modified light calcium powder, bentonite and mica vermiculite in S13 is 3-5:1-2:10-15, and it is stirred at 300-500 rpm for 1-2 hours; the mass ratio of the mixture, deionized water and acrylic polysiloxane is 30-35:100:0.5-2, and it is modified at 50-60℃ for 1-2 hours, and then dried at 70-80℃.

5. The inorganic mixture coating for protecting metal roofs according to claim 1, characterized in that, The preparation method of the aqueous silicone-acrylic emulsion includes the following steps: S21. Add deionized water and emulsifier to a reaction vessel and stir to emulsify. Add KH-570 and KH-802 and heat to react. After cooling to room temperature, add deionized water to dilute and obtain a silicone-based emulsion. S22. Acrylic acid, hydroxyethyl acrylate, butyl acrylate, methacrylic acid and methyl methacrylate are added to a silicone-based emulsion, and azobisisobutyronitrile initiator is added dropwise and the mixture is heated to obtain a mixture. After cooling the mixture, ammonia water is added to neutralize it to obtain an aqueous silicone-acrylic emulsion.

6. The inorganic mixture coating for protecting metal roofs according to claim 5, characterized in that, In S21, the emulsifier is prepared by mixing sodium dodecyl sulfate and dodecyl alcohol polyoxyethylene ether at a mass ratio of 1:1~2, homogenized at 1000~2000 rpm for 5~10 min, and the mass ratio of deionized water, emulsifier, KH-570 and KH-802 is 100~110:2~5:10~15:3~5. The reaction is carried out at 50~60℃ for 4~6 h, and then diluted with deionized water to a solid content of 8~10 wt%. In S22, the mass ratio of acrylic acid, hydroxyethyl acrylate, butyl acrylate, methacrylic acid, methyl methacrylate, silicone emulsion and azobisisobutyronitrile initiator is 3~5:8~10:13~16:4~6:15~18:100:1~4, and the reaction is carried out at 80~85℃ for 4~6 h.

7. A method for preparing an inorganic mixture coating for protecting metal roofs, characterized in that, Includes the following steps: S1. Add the raw materials of component B to the mixer in sequence, add component A while stirring, speed up the stirring and dispersion to obtain a slurry; S2. Filter the slurry to remove large particles, and let it stand at room temperature to mature, thus obtaining an inorganic mixture coating for protecting metal roofs.

8. The method for preparing an inorganic mixture coating for protecting metal roofs according to claim 7, characterized in that, In S1, component B is stirred and mixed at a speed of 300-500 rpm for 20-30 minutes. After adding component A, the mixture is stirred at a speed of 1000-2000 rpm for 20-30 minutes. The amount of component B is 20-35% of the mass of component A. In S2, the mixture is passed through a 300-mesh sieve and allowed to stand at room temperature for 1-2 hours to mature.

9. The application of an inorganic mixture coating for protecting metal roofs, characterized in that, To prepare a protective coating for metal roofs, the surface of a stainless steel metal roof is cleaned with a high-pressure water gun and dried completely. The coating is then sprayed onto the surface at an output pressure of 15-25 MPa and a spraying speed of 20-40 m / min. The coating is dried at room temperature and cured for 1-3 days to obtain a protective coating for metal roofs with an average thickness of 250-350 μm.

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