A surface anti-weathering coating liquid for stone cultural relics and an anti-weathering treatment method

Abstract

This invention discloses a surface anti-weathering coating and anti-weathering treatment method for stone cultural relics, comprising the following steps: S1, preparing modified cyclodextrin by taking calcium hydroxide, sodium hydroxide, and β-cyclodextrin; S2, preparing calcium hydroxide by taking calcium oxide and modified cyclodextrin; S3, mixing calcium hydroxide with carbon powder and heat-treating to obtain modified calcium hydroxide particles; S4, adding the modified calcium hydroxide particles to an alcohol solvent and stirring to mix evenly, thus obtaining the anti-weathering coating. This invention mixes the encapsulated calcium hydroxide with carbon powder and utilizes the principle of induction heating to rapidly raise the temperature of the carbon powder in a short time, thereby causing partial structural destruction of the cyclodextrin at high temperature, exposing the calcium hydroxide. This invention, through a special modification method, improves the dispersion effect of calcium hydroxide in the alcohol solvent while avoiding the impact of the above modification on the anti-weathering effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of protective materials, and particularly relates to a surface anti-weathering coating solution for stone cultural relics and an anti-weathering treatment method. BACKGROUND

[0002] There are a large number of stone cultural relics made of carbonate rocks as the main material, which are important physical reference materials for history, archaeology and art. Because the solubility product of the main component calcium carbonate is low, it is easy to be dissolved, and weathering has become one of the main diseases of such cultural relics.

[0003] Studies have shown that surface weathering of stone cultural relics is caused by physical, chemical and biological weathering due to acid rain, atmospheric pollutants and other factors. Ultimately, gaseous / liquid water and soluble salts are the key factors that cause surface weathering. With the repeated changes in environmental temperature and humidity, the soluble salts periodically change in dissolution and recrystallization, and the extrusion pressure generated by the crystallization will make them crumbly and deteriorate.

[0004] Inorganic reinforcing materials have been widely used since the nineteenth century. Most inorganic reinforcing agents use the salt content in the solution to condense in the stone pores or to chemically react with the stone to fill the stone pores to form a barrier or replacement layer. Among them, nano calcium hydroxide is a promising inorganic nano material for the protection of murals and stone cultural relics.

[0005] Some composite materials for the protection of stone cultural relics using calcium hydroxide as an inorganic reinforcing material are described in the prior art, as shown in references 1 and 2:

[0006] Reference 1: Chinese patent document with publication number CN112194504A

[0007] Reference 1 describes a calcium hydroxide solution for the protection of stone cultural relics. Calcium salt, organic base, ammonia, modified perfluoro coupling agent and thickening agent (cyclodextrin) are added as solutes to a solution composed of isopropyl alcohol and deionized water to obtain a calcium hydroxide solution. The present application applies hydrophobic and oleophobic technology to the field of cultural relic protection, especially to the field of calcium salt reinforcement of weathered stone cultural relics. This method uses modified perfluorosilane to perform hydrophobic and oleophobic treatment on stone cultural relics, reducing the effect of acid rain on stone cultural relics. The cross-linking effect generated by the method can reinforce weathered stone cultural relics. The calcium salt penetrates into the cracks of stone cultural relics, and the calcium carbonate generated by the reaction with carbon dioxide can enhance the filling of the gaps, with the characteristics of safety, high efficiency, no damage and no side effects.

[0008] Reference 2: Chinese patent document with publication number CN114656284A

[0009] Reference 2 describes a nano-clay-calcium hydroxide composite material for repair and reinforcement. By controlling the ionization degree of calcium and hydroxide ions and the supersaturation of the solution in a nano-clay dispersion, nano-calcium hydroxide is grown in situ on nano-clay sheets, thus preparing the nano-clay-calcium hydroxide composite material. This composite material, after being uniformly dispersed in an alcohol or alcohol-water composite solution, is applied to the repair and reinforcement of stone cultural relics and their surfaces. The composite ratio of clay and calcium hydroxide is adjustable and controllable, and the dimensions are uniform. The prepared protective solution is highly dispersed, has good fluidity and strong permeability, good compatibility with rocks, is free of soluble salts, has suitable rigidity and hardness, and an appropriate curing time. It exhibits high applicability, safety, durability, and no derivative damage in the protection of stone cultural relics.

[0010] Lime water reinforcement of limestone utilizes the reaction of calcium hydroxide with carbon dioxide in the air to generate calcium carbonate solid, which fills the pores of the limestone to reinforce stone artifacts. However, references 1 and 2 use cyclodextrin and clay for modification, respectively. Although these modifications can improve the dispersibility of calcium hydroxide, due to the special molecular structures of cyclodextrin and clay, calcium hydroxide is easily trapped within them, affecting its reaction with carbon dioxide in the air and thus impacting its weathering resistance. Summary of the Invention

[0011] The purpose of this invention is to solve the above-mentioned technical problems existing in the prior art and to provide a surface anti-weathering coating liquid and anti-weathering treatment method for stone cultural relics.

[0012] To address the shortcomings of the aforementioned technical problems, the present invention provides a method for preparing a surface anti-weathering coating for stone artifacts, comprising the following steps:

[0013] S1. Mix calcium hydroxide and sodium hydroxide, add them to deionized water and stir until homogeneous. Then add starch microspheres and continue stirring for 2-3 hours. Finally, add β-cyclodextrin and transfer the mixture to a reaction vessel. Control the reaction temperature at 15-18℃ and add propylene oxide dropwise to the reaction vessel. After the dropwise addition is complete, raise the temperature to 22-25℃ at a rate of 0.5-1℃ / min and maintain the temperature for 20-30 minutes. After the reaction is complete, filter to separate the starch microspheres and spray-dry the reaction solution to obtain modified cyclodextrin for later use.

[0014] S2. Mix calcium oxide and modified cyclodextrin and add them to deionized water to prepare a suspension. Place the suspension in an ultrasonic reactor and ultrasonically disperse it evenly. Place the ultrasonically dispersed suspension in an oven at 60~75℃ for heat treatment. After the treatment, filter under reduced pressure and dry under vacuum to obtain calcium hydroxide for later use.

[0015] S3. Take calcium hydroxide and carbon powder, mix them and stir evenly. Then transfer the mixture to a container with an induction coil. Under an inert atmosphere, turn on the induction coil and process for 10~30s. After natural cooling, separate the carbon powder and calcium hydroxide powder to obtain modified calcium hydroxide granules for later use.

[0016] S4. Add the modified calcium hydroxide granules to the alcohol solvent and stir to mix well to obtain the weathering-resistant coating liquid.

[0017] As a further optimization of the preparation method of the anti-weathering coating liquid for stone cultural relics of the present invention: the weight ratio of calcium hydroxide, sodium hydroxide, starch microspheres and β-cyclodextrin added in step S1 is 10:1~2:0.2~0.5:40~60.

[0018] As a further optimization of the preparation method of the anti-weathering coating liquid for stone cultural relics of the present invention: the weight ratio of calcium oxide and modified cyclodextrin added in step S2 is 2~5:1.

[0019] As a further optimization of the preparation method of the anti-weathering coating liquid for stone cultural relics of the present invention: the ratio of modified calcium hydroxide to carbon powder in step S3 is 10:0.1~2, and the particle size of carbon powder is 2-3 times that of modified calcium hydroxide.

[0020] As a further optimization of the preparation method of the anti-weathering coating liquid for the surface of stone cultural relics of the present invention: the power of the induction coil in step S3 is 600~1200W.

[0021] As a further optimization of the preparation method of the anti-weathering coating liquid for stone cultural relics of the present invention: the alcohol solvent in step S4 is ethanol, isopropanol or n-butanol.

[0022] As a further optimization of the preparation method of the anti-weathering coating liquid for stone cultural relics of the present invention: the weight ratio of the modified calcium hydroxide to the alcohol solvent is 1~5:100.

[0023] The present invention also provides a surface anti-weathering coating liquid for stone cultural relics, which is prepared by the above-mentioned method.

[0024] The present invention also provides a method for surface anti-weathering treatment of stone cultural relics: first, clean the surface of the stone cultural relic to be treated with a wool brush, then apply the surface anti-weathering coating liquid to the surface of the stone cultural relic, let it stand for 1 to 2 days, apply another coat, and let it stand for 1 to 2 days to complete the anti-weathering treatment.

[0025] As a further optimization of the surface anti-weathering treatment method for stone cultural relics of the present invention: after the anti-weathering coating is applied, deionized water is sprayed on the surface of the stone cultural relics every day for 5-10 days.

[0026] This invention offers the following advantages: Calcium hydroxide is modified with cyclodextrin. The molecular structure of cyclodextrin resembles a hollow cylinder or cone, with each glucose unit arranged in three-dimensional space to form a hollow cavity. The inner wall of the cavity is mainly composed of CH bonds, exhibiting hydrophobicity. This allows cyclodextrin to form an inclusion structure with calcium hydroxide. Furthermore, the cyclodextrin used in this invention is hydroxypropylated β-cyclodextrin, resulting in good dispersion of the cyclodextrin-calcium hydroxide inclusion complex in alcohol solvents. However, while the inclusion treatment of calcium hydroxide with cyclodextrin improves the dispersion of calcium hydroxide in alcohol solvents, it affects its interaction with carbon dioxide in the air. Therefore, this invention mixes the inclusion-treated calcium hydroxide with charcoal powder and utilizes induction heating to rapidly heat the charcoal powder within a short time, causing partial structural damage of the cyclodextrin at high temperatures, thus exposing the calcium hydroxide. This invention, through a special modification method, improves the dispersion of calcium hydroxide in alcohol solvents while avoiding the aforementioned impact on the anti-weathering effect. Detailed Implementation

[0027] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0028] <Weatherproof Coating>

[0029] A method for preparing a surface anti-weathering coating for stone cultural relics includes the following steps:

[0030] S1. Mix calcium hydroxide and sodium hydroxide, add them to deionized water and stir until homogeneous. Then add starch microspheres and continue stirring for 2-3 hours. Finally, add β-cyclodextrin and transfer the mixture to a reaction vessel. Control the reaction temperature at 15-18℃ and add propylene oxide dropwise to the reaction vessel. After the addition is complete, raise the temperature to 22-25℃ at a rate of 0.5-1℃ / min and maintain the temperature for 20-30 minutes. After the reaction is complete, filter to separate the starch microspheres and spray-dry the reaction solution to obtain modified cyclodextrin for later use.

[0031] The weight ratio of calcium hydroxide, sodium hydroxide, starch microspheres, and β-cyclodextrin is 10:1~2:0.2~0.5:40~60. Starch microspheres are micron- or submicron-sized spherical particles prepared from natural starch or other modified starches as the main raw materials through physical or chemical methods.

[0032] S2. Mix calcium oxide and modified cyclodextrin and add them to deionized water to prepare a suspension. Place the suspension in an ultrasonic reactor and ultrasonically disperse it evenly. Place the ultrasonically dispersed suspension in an oven at 60~75℃ for heating treatment. After the treatment, filter under reduced pressure and dry under vacuum to obtain calcium hydroxide for later use.

[0033] The weight ratio of calcium oxide to modified cyclodextrin is 2~5:1.

[0034] S3. Mix calcium hydroxide and carbon powder and stir evenly. Then transfer the mixture to a container with an induction coil. Under an inert atmosphere, turn on the induction coil and process for 10-30 seconds. After natural cooling, separate the carbon powder and calcium hydroxide powder to obtain modified calcium hydroxide granules for later use.

[0035] The ratio of modified calcium hydroxide to carbon powder is 10:0.1~2, and the particle size of the carbon powder is 2-3 times that of the modified calcium hydroxide. The significant difference in particle size between the carbon powder and modified calcium hydroxide facilitates separation after heat treatment. However, it is important to note that the difference should not be too large, otherwise it will affect the effectiveness of the heat treatment.

[0036] The induction coil has a power of 600-1200W. When alternating current passes through the induction coil, an alternating magnetic field is generated inside the coil. According to Faraday's law of electromagnetic induction, as the magnetic field changes over time, eddy currents (also known as eddy currents or skin effect currents) are induced within the conductive material placed in the magnetic field. These eddy currents are generated because the change in the magnetic field induces an electromotive force within the conductor, thus forming a current. Eddy currents generate heat: the eddy currents flowing inside the conductive material (such as metal) encounter the material's own resistance. According to Joule's law, current generates heat when passing through a resistor. Therefore, as the eddy currents pass through the conductor, due to the resistance, they continuously consume electrical energy and convert it into heat energy. A key characteristic of induction heating is its ability to generate locally concentrated heat within the conductive material, rather than a uniform distribution. This is because the eddy currents are mainly concentrated on the surface of the conductor (skin effect), causing the temperature near the coil to rise faster, thus achieving efficient localized heating.

[0037] S4. Add the modified calcium hydroxide granules to the alcohol solvent and stir to mix well to obtain the weathering-resistant coating liquid.

[0038] The alcohol solvent is ethanol, isopropanol, or n-butanol. The weight ratio of modified calcium hydroxide to alcohol solvent is 1~5:100.

[0039] <Methods for preventing weathering>

[0040] A method for surface anti-weathering treatment of stone cultural relics: First, clean the surface of the stone cultural relic to be treated with a wool brush, then apply the above-mentioned surface anti-weathering coating to the surface of the stone cultural relic, let it stand for 1 to 2 days, apply another coat, and let it stand for 1 to 2 days to complete the anti-weathering treatment.

[0041] Because alcohol solutions are highly volatile, when applied to the surface of cultural relics, the calcium hydroxide nanoparticles that have penetrated into the relics are carried back to the surface as the alcohol evaporates, resulting in a "regression" phenomenon. This phenomenon limits the penetration depth of the nano-calcium hydroxide within the relics. To mitigate the impact of this "regression" on penetration depth, the following treatment can be implemented during the anti-weathering process: After the anti-weathering coating is applied, deionized water should be sprayed onto the surface of the stone relics every day for 5-10 days, using a water-wet compress method to improve the situation.

[0042] <Example 1>

[0043] S1. Take calcium hydroxide, sodium hydroxide and starch microspheres in a weight ratio of 10:1:0.2:40. Mix calcium hydroxide and sodium hydroxide and add them to deionized water and stir evenly. Then add starch microspheres and continue stirring for 2 hours. Finally, add β-cyclodextrin and transfer the mixture to a reaction vessel. Control the reaction temperature at 15℃ and add propylene oxide dropwise to the reaction vessel. After the dropwise addition is completed, raise the temperature to 25℃ at a rate of 0.5℃ / min and keep it at a constant temperature for 20 minutes. After the end, filter and separate the starch microspheres. Spray dry the reaction solution to obtain modified cyclodextrin for later use.

[0044] S2. Calcium oxide and modified cyclodextrin are mixed at a weight ratio of 2:1 and then added to deionized water to prepare a suspension. The suspension is placed in an ultrasonic reactor and ultrasonically dispersed evenly. The ultrasonically dispersed suspension is placed in a 60°C oven for heat treatment. After the treatment, it is filtered under reduced pressure and dried under vacuum to obtain calcium hydroxide for later use.

[0045] S3. Mix calcium hydroxide and carbon powder at a weight ratio of 5:1 and stir evenly. Then transfer the mixture to a container with an induction coil. Under an inert atmosphere, turn on the induction coil for 20 seconds. After natural cooling, separate the carbon powder and calcium hydroxide powder to obtain modified calcium hydroxide granules for later use.

[0046] S4. Add modified calcium hydroxide granules to an alcohol solvent at a weight ratio of 2:100, stir and mix well to obtain the weathering-resistant coating liquid.

[0047] Tests using a UV-Vis spectrophotometer showed that the anti-weathering coating had a stability time exceeding 10 hours. When the solution was applied to the surface of a stone artifact and a section was cut perpendicular to the surface, the penetration depth of the anti-weathering coating into the stone artifact reached 6.5 cm.

[0048] <Example 2>

[0049] S1. Take calcium hydroxide, sodium hydroxide and starch microspheres in a weight ratio of 10:2:0.5:50. Mix calcium hydroxide and sodium hydroxide and add them to deionized water and stir evenly. Then add starch microspheres and continue stirring for 3 hours. Finally, add β-cyclodextrin and transfer the mixture to a reaction vessel. Control the reaction temperature at 16℃ and add propylene oxide dropwise to the reaction vessel. After the dropwise addition is completed, raise the temperature to 22℃ at a rate of 0.8℃ / min and keep it constant for 25 minutes. After the end, filter and separate the starch microspheres. Spray dry the reaction solution to obtain modified cyclodextrin for later use.

[0050] S2. Calcium oxide and modified cyclodextrin are mixed at a weight ratio of 3:1 and then added to deionized water to prepare a suspension. The suspension is placed in an ultrasonic reactor and ultrasonically dispersed evenly. The ultrasonically dispersed suspension is placed in a 65°C oven for heat treatment. After the treatment, it is filtered under reduced pressure and dried under vacuum to obtain calcium hydroxide for later use.

[0051] S3. Mix calcium hydroxide and carbon powder in a weight ratio of 2:1 and stir evenly. Then transfer the mixture to a container with an induction coil. Under an inert atmosphere, turn on the induction coil for 30 seconds. After natural cooling, separate the carbon powder and calcium hydroxide powder to obtain modified calcium hydroxide granules for later use.

[0052] S4. Add modified calcium hydroxide granules to an alcohol solvent at a weight ratio of 3:100, stir and mix well to obtain the weathering-resistant coating liquid.

[0053] Tests using a UV-Vis spectrophotometer showed that the anti-weathering coating had a stability time exceeding 11 hours. When the solution was applied to the surface of a stone artifact and a section was cut perpendicular to the surface, the penetration depth of the anti-weathering coating into the stone artifact reached 6.3 cm.

[0054] <Example 3>

[0055] S1. Take calcium hydroxide, sodium hydroxide and starch microspheres in a weight ratio of 10:2:0.2:45. Mix calcium hydroxide and sodium hydroxide and add them to deionized water and stir evenly. Then add starch microspheres and continue stirring for 3 hours. Finally, add β-cyclodextrin and transfer the mixture to a reaction vessel. Control the reaction temperature at 17°C and add propylene oxide dropwise to the reaction vessel. After the dropwise addition is complete, raise the temperature to 23°C at a rate of 1°C / min and keep it constant for 30 minutes. After the end, filter and separate the starch microspheres. Spray dry the reaction solution to obtain modified cyclodextrin for later use.

[0056] S2. Calcium oxide and modified cyclodextrin are mixed at a weight ratio of 3:1 and then added to deionized water to prepare a suspension. The suspension is placed in an ultrasonic reactor and ultrasonically dispersed evenly. The ultrasonically dispersed suspension is placed in a 65°C oven for heat treatment. After the treatment, it is filtered under reduced pressure and dried under vacuum to obtain calcium hydroxide for later use.

[0057] S3. Mix calcium hydroxide and carbon powder at a weight ratio of 5:1 and stir evenly. Then transfer the mixture to a container with an induction coil. Under an inert atmosphere, turn on the induction coil for 30 seconds. After natural cooling, separate the carbon powder and calcium hydroxide powder to obtain modified calcium hydroxide granules for later use.

[0058] S4. Add modified calcium hydroxide granules to an alcohol solvent at a weight ratio of 4:100, stir and mix well to obtain the weathering-resistant coating liquid.

[0059] Tests using a UV-Vis spectrophotometer showed that the anti-weathering coating had a stability time exceeding 10 hours. When the solution was applied to the surface of a stone artifact and a section was cut perpendicular to the surface, the penetration depth of the anti-weathering coating into the stone artifact reached 6.8 cm.

[0060] <Example 4>

[0061] S1. Take calcium hydroxide, sodium hydroxide and starch microspheres in a weight ratio of 10:1.5:0.4:40. Mix calcium hydroxide and sodium hydroxide and add them to deionized water and stir evenly. Then add starch microspheres and continue stirring for 2 hours. Finally, add β-cyclodextrin and transfer the mixture to a reaction vessel. Control the reaction temperature at 18°C ​​and add propylene oxide dropwise to the reaction vessel. After the dropwise addition is completed, raise the temperature to 25°C at a rate of 1°C / min and keep it constant for 30 minutes. After the end, filter and separate the starch microspheres. Spray dry the reaction solution to obtain modified cyclodextrin for later use.

[0062] S2. Calcium oxide and modified cyclodextrin are mixed at a weight ratio of 3:1 and then added to deionized water to prepare a suspension. The suspension is placed in an ultrasonic reactor and ultrasonically dispersed evenly. The ultrasonically dispersed suspension is placed in a 75°C oven for heat treatment. After the treatment, it is filtered under reduced pressure and dried under vacuum to obtain calcium hydroxide for later use.

[0063] S3. Mix calcium hydroxide and carbon powder in a weight ratio of 2:1 and stir evenly. Then transfer the mixture to a container with an induction coil. Under an inert atmosphere, turn on the induction coil and process for 15 seconds. After natural cooling, separate the carbon powder and calcium hydroxide powder to obtain modified calcium hydroxide granules for later use.

[0064] S4. Add modified calcium hydroxide granules to an alcohol solvent at a weight ratio of 5:100, stir and mix well to obtain the weathering-resistant coating liquid.

[0065] Tests using a UV-Vis spectrophotometer showed that the anti-weathering coating had a stability time exceeding 9 hours. When the solution was applied to the surface of a stone artifact and a section was cut perpendicular to the surface, the penetration depth of the anti-weathering coating into the stone artifact reached 6.1 cm.

[0066] <Example 5>

[0067] S1. Take calcium hydroxide, sodium hydroxide and starch microspheres in a weight ratio of 10:1:0.4:50. Mix calcium hydroxide and sodium hydroxide and add them to deionized water and stir evenly. Then add starch microspheres and continue stirring for 2 hours. Finally, add β-cyclodextrin and transfer the mixture to a reaction vessel. Control the reaction temperature at 15℃ and add propylene oxide dropwise to the reaction vessel. After the dropwise addition is completed, raise the temperature to 25℃ at a rate of 0.6℃ / min and keep it constant for 20 minutes. After the end, filter and separate the starch microspheres. Spray dry the reaction solution to obtain modified cyclodextrin for later use.

[0068] S2. Calcium oxide and modified cyclodextrin are mixed at a weight ratio of 4:1 and then added to deionized water to prepare a suspension. The suspension is placed in an ultrasonic reactor and ultrasonically dispersed evenly. The ultrasonically dispersed suspension is placed in a 75°C oven for heat treatment. After the treatment, it is filtered under reduced pressure and dried under vacuum to obtain calcium hydroxide for later use.

[0069] S3. Mix calcium hydroxide and carbon powder in a weight ratio of 4:1 and stir evenly. Then transfer the mixture to a container with an induction coil. Under an inert atmosphere, turn on the induction coil and process for 15 seconds. After natural cooling, separate the carbon powder and calcium hydroxide powder to obtain modified calcium hydroxide granules for later use.

[0070] S4. Add modified calcium hydroxide granules to an alcohol solvent at a weight ratio of 3:100, stir and mix well to obtain the weathering-resistant coating liquid.

[0071] Tests using a UV-Vis spectrophotometer showed that the anti-weathering coating had a stability time exceeding 9.5 hours. When the solution was applied to the surface of a stone artifact and a section was cut perpendicular to the surface, the penetration depth of the anti-weathering coating into the stone artifact reached 6.2 cm.

[0072] <Comparative Example 1>

[0073] Commercially available calcium hydroxide granules were added to an alcohol solvent at a weight ratio of 3:100 and stirred until homogeneous to obtain the coating solution. This anti-weathering coating solution has a stability time of less than 1 hour. When the solution was applied to the surface of a stone artifact and a section was cut perpendicular to the surface, the penetration depth of the anti-weathering coating solution into the stone artifact was found to be only 2.2 cm.

[0074] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A method for preparing a surface anti-weathering coating for stone cultural relics, characterized in that: Includes the following steps: S1. Mix calcium hydroxide and sodium hydroxide, add them to deionized water and stir until homogeneous. Then add starch microspheres and continue stirring for 2-3 hours. Finally, add β-cyclodextrin and transfer the mixture to a reaction vessel. Control the reaction temperature at 15-18℃ and add propylene oxide dropwise to the reaction vessel. After the dropwise addition is complete, raise the temperature to 22-25℃ at a rate of 0.5-1℃ / min and maintain the temperature for 20-30 minutes. After the reaction is complete, filter to separate the starch microspheres and spray-dry the reaction solution to obtain modified cyclodextrin for later use. S2. Calcium oxide and modified cyclodextrin are mixed and added to deionized water to prepare a suspension. The suspension is placed in an ultrasonic reactor and ultrasonically dispersed evenly. The ultrasonically dispersed suspension is placed in an oven at 60~75℃ for heating treatment. After the treatment, it is filtered under reduced pressure and dried under vacuum to obtain a calcium hydroxide-based intermediate product for later use. S3. Take the calcium hydroxide-based intermediate product and mix it with the carbon powder and stir it evenly. Then transfer the mixture to a container with an induction coil. Under an inert atmosphere, turn on the induction coil for 10~30s. The power of the induction coil is 600~1200W. After natural cooling, separate the carbon powder and the calcium hydroxide-based intermediate product to obtain modified calcium hydroxide particles for later use. S4. Add the modified calcium hydroxide granules to the alcohol solvent and stir to mix well to obtain the surface anti-weathering coating.

2. The method for preparing a surface anti-weathering coating for stone cultural relics as described in claim 1, characterized in that: In step S1, the weight ratio of calcium hydroxide, sodium hydroxide, starch microspheres and β-cyclodextrin is 10:1~2:0.2~0.5:40~60.

3. The method for preparing a surface anti-weathering coating for stone cultural relics as described in claim 1, characterized in that: In step S2, the weight ratio of calcium oxide to modified cyclodextrin is 2~5:

1.

4. The method for preparing a surface anti-weathering coating for stone cultural relics as described in claim 1, characterized in that: The alcohol solvent in step S4 is ethanol, isopropanol, or n-butanol.

5. The method for preparing a surface anti-weathering coating for stone cultural relics as described in claim 1, characterized in that: The weight ratio of the modified calcium hydroxide particles to the alcohol solvent is 1~5:

100.

6. The surface weathering-resistant coating liquid prepared by the method according to any one of claims 1 to 5.

7. A method for surface weathering protection treatment of stone cultural relics, characterized in that: First, clean the surface of the stone artifact to be treated with a wool brush. Then, apply the surface anti-weathering coating liquid as described in claim 6 to the surface of the stone artifact, let it stand for 1 to 2 days, apply another coat, and let it stand for 1 to 2 days to complete the anti-weathering treatment.

8. The surface weathering prevention treatment method for stone cultural relics as described in claim 7, characterized in that: After the weathering-resistant coating is applied, spray deionized water onto the surface of the stone artifact every day for 5 to 10 days.