A kind of anti-weathering coating for red sandstone cultural relics and preparation method thereof

Abstract

The invention discloses a red sandstone cultural relic anti-weathering coating and a preparation method thereof, and relates to the field of red sandstone cultural relic anti-weathering coating, wherein the coating comprises the following components in parts by weight: 85-110 parts of anhydrous ethanol, 10-15 parts of film-forming components, 0.5-1.5 parts of salt crystallization inhibitor, 0.5-2 parts of pore-forming agent, and 0.01-0.06 parts of composite nano-modifier; the film-forming components include dodecyltrimethoxysilane. After the red sandstone cultural relic uses the coating of the invention, not only will the original color morphology of the red sandstone cultural relic not be covered, but the reinforced and repaired red sandstone cultural relic also has high surface hardness, high hydrophobicity, high air permeability, excellent acid resistance, salt resistance and other properties.

Description

Technical Field

[0001] The invention relates to the field of red sandstone cultural relic coatings, and in particular to a red sandstone cultural relic anti-weathering coating and a preparation method thereof. Background Art

[0002] Red sandstone is widely used in cultural relic carving due to its soft texture. It is one of the main carriers of ancient cave temple cultural relics. At the same time, due to the low strength and high porosity of red sandstone, it is easily eroded by external weathering factors such as water, acid rain, and salt crystallization. In view of the principles of "minimum intervention" and "unchanged original state of cultural relics", it is required that sandstone anti-weathering protection materials should have good compatibility and permeability with cultural relics, as well as excellent weather resistance and air permeability, and small color difference between materials and cultural relics. However, the current anti-weathering coatings for red sandstone cultural relics have the difficulty of easily covering the original color of cultural relics and it is difficult to take into account the waterproofness, air permeability and durability of cultural relics. Therefore, it is urgent to develop a new coating for anti-weathering of red sandstone cultural relics.

[0003] 202010513456.3 announced a surface modification material for red sandstone applied within the water level variation zone. It is a polyurethane material with good protective effect. Its disadvantages are poor water resistance and easy to change the morphology of red sandstone.

[0004] 202210528270.4 announced a nano-coating for anti-weathering and anti-corrosion protection of red sandstone in water conservancy projects and its preparation method. The coating belongs to the acrylic resin type and has the characteristics of good water resistance, colorless and transparent, no change in the morphology of red sandstone, and high bonding strength. However, since acrylic resin is not breathable, red sandstone is prone to salt expansion, heat expansion, water vapor expansion and other phenomena.

[0005] 202410024242.8 announced a nano-composite material modified silicone stone reinforcer, which belongs to the class of organosilane materials. By modifying the silicone resin material with graphene oxide, the coating has better protective effects in terms of stain resistance, water resistance and air permeability. The disadvantages are poor salt resistance and easy change of the morphology of the cultural relics themselves.

[0006] In view of the problems of the current anti-weathering coating for red sandstone cultural relics, such as easy change of the appearance of red sandstone cultural relics, poor water resistance, insufficient air permeability, poor salt resistance, etc., a red sandstone cultural relic anti-weathering coating and a preparation method thereof are urgently needed. Summary of the invention

[0007] One object of the present invention is to provide a red sandstone cultural relic anti-weathering coating and a preparation method thereof, so as to obtain a red sandstone cultural relic anti-weathering coating having good water resistance, high surface hardness, excellent air permeability, good salt resistance and acid resistance, and small color difference with the cultural relic.

[0008] The present invention discloses a red sandstone cultural relic anti-weathering coating, characterized in that it comprises the following components in parts by weight: 85-110 parts of anhydrous ethanol, 10-15 parts of a film-forming component, 0.5-1.5 parts of a salt crystallization inhibitor, 0.5-2 parts of a pore-forming agent, and 0.01-0.06 parts of a composite nano-modifier;

[0009] The film-forming component includes dodecyltrimethoxysilane.

[0010] The present invention selects dodecyltrimethoxysilane which has good compatibility and permeability with red sandstone cultural relics as the main film-forming substance. The color difference between dodecyltrimethoxysilane and the material is small. A pore-forming agent is combined to adjust the pore structure, thereby improving the air permeability of the cultural relics. A salt crystallization inhibitor is used to improve the salt resistance of the cultural relics. A composite nano-modifier is used to improve the water resistance, toughness, anti-fouling and anti-ultraviolet properties of the cultural relics. Thus, a multifunctional anti-weathering coating for red sandstone cultural relics with excellent performance is obtained.

[0011] Among them, dodecyltrimethoxysilane is a long-chain silicone material. Since its molecular chain contains both organic alkyl groups and inorganic siloxy groups, the coating has excellent waterproof properties of alkyl groups and good compatibility with inorganic silicate matrix materials.

[0012] Furthermore, the film-forming component also includes red sandstone powder and dodecylphenol polyoxyethylene ether. Preferably, the weight ratio of dodecyltrimethoxysilane, red sandstone powder and dodecylphenol polyoxyethylene ether is 8-15:0.5-2.5:0.5-2.

[0013] Specifically, red sandstone powder is used to improve the compatibility and surface hardness of the film-forming material with the materials of cultural relics; red sandstone powder is added not only because the red sandstone powder has the same texture as the materials of cultural relics and has good compatibility; at the same time, since the materials used are all red sandstone, the color of the cultural relics will not be changed after adding it; secondly, through the combination of particles between the composite nano-modifier and the red sandstone powder, a composite pore structure can be formed, which helps to enhance the air permeability of the coating.

[0014] Dodecylphenol polyoxyethylene ether is an emulsifier. The emulsifier is added to ensure that two or more immiscible components in the system form a stable emulsion.

[0015] On the other hand, adding a salt crystallization inhibitor to the coating can increase the saturation of salt that would otherwise crystallize on the surface of the cultural relic. Under the capillary action of the pore-forming agent to prepare special pores, the soluble salt will be discharged from the cultural relic along with the water; this ensures that the coating has good compatibility, waterproofness, air permeability, wear resistance and other properties while improving the salt resistance of the material. Preferably, the salt crystallization inhibitor includes one or more of phosphocitric acid, aminoacetamide, and disodium octaborate tetrahydrate.

[0016] Adding a composite nano modifier to the coating can improve the toughness of the coating. Preferably, the composite nano modifier includes the following components in parts by weight: 0.5-5 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, 0.01-0.5 parts of nano ZrO2-TiO2-g-C3N4 powder and 0.01-0.5 parts of nano cellulose.

[0017] Among them, the γ-(2,3-epoxypropoxy)propyltrimethoxysilane is a silane coupling agent, which can not only improve the interface performance between the nano-modified material and the aggregate, but also enhance the dispersion effect of nano ZrO2-TiO2-g-C3N4 powder and nano cellulose; under the action of the silane coupling agent, the nano ZrO2-TiO2-g-C3N4 powder is fully grafted onto the nano cellulose, and the two-dimensional nano ZrO2-TiO2-g-C3N4 material has higher light absorption than the nano ZrO2-TiO2-g-C3N4 powder. The collection capacity, charge separation efficiency and utilization rate, as well as a large number of atoms with lower coordination make it have higher photocatalytic efficiency, and therefore have stronger UV resistance, antibacterial and anti-fouling capabilities; Nano ZrO2-TiO2-g-C3N4 powder grafted on nanocellulose can improve the hydrophobicity of nanocellulose; Nano ZrO2-TiO2-g-C3N4 powder grafted on nanocellulose can increase the roughness of nanocellulose, and after the coating is dried and hardened, the friction between the fiber and the coating is enhanced, and the toughness of the coating is improved through the bridging effect of the fiber.

[0018] Based on the above components, a method for preparing a red sandstone cultural relic anti-weathering coating comprises the following steps:

[0019] S1 prepares pore formers, film-forming components, salt crystallization inhibitors and composite nano-modifiers;

[0020] S2: adding the film-forming component, the salt crystallization inhibitor and the pore-forming agent into anhydrous ethanol and stirring to obtain solution A;

[0021] The red sandstone powder and dodecylphenol polyoxyethylene ether are added into dodecyltrimethoxysilane, and the film-forming component is obtained by stirring after ultrasonic dispersion.

[0022] Add γ-(2,3-epoxypropoxy)propyltrimethoxysilane to deionized water and stir; add nano ZrO2-TiO2-g-C3N4 powder and nano cellulose, ultrasonically disperse and stir to obtain a mixed suspension; stir the mixed suspension at room temperature, and then pour the stirred mixed suspension into a hydrothermal reactor; place the hydrothermal reactor in an oven at 110°C for 8 hours; after the reaction is completed, wash, dry and bake the reactants to obtain a composite nano modifier.

[0023] S3: adding the composite nano-modifier into solution A, dispersing by ultrasonic, and stirring to obtain the coating.

[0024] Furthermore, the pore-forming agent includes gelatin particles, and the particle size of the gelatin particles is 400-1000 mesh. The coatings include a first coating, a second coating, and a third coating from bottom to top, the pore-forming agent in the first coating includes gelatin particles with a particle size of r1, the pore-forming agent in the second coating includes gelatin particles with a particle size of r2, and the pore-forming agent in the third coating includes gelatin particles with a particle size of r3, r1>r2>r3. Repeat steps S1-S4 three times to obtain three coatings, which are the first coating, the second coating, and the third coating, respectively. The pore-forming agent in the first coating includes gelatin particles with a particle size of r1, the pore-forming agent in the second coating includes gelatin particles with a particle size of r2, and the pore-forming agent in the third coating includes gelatin particles with a particle size of r3, r1>r2>r3;

[0025] The first coating, the second coating and the third coating are sequentially applied to the red sandstone cultural relics. Through the layered coating method, the coatings have a gradient pore structure after drying. This greatly enhances the air permeability of the cultural relics while ensuring that the cultural relics have good waterproof properties. The special pore structure can discharge the moisture inside the cultural relics to the outside through capillary action. In addition, gelatin will slowly dissolve under the action of water.

[0026] In step S2, the method for preparing nano ZrO2-TiO2-g-C3N4 powder includes:

[0027] Add nano ZrO2, nano TiO2 and nano g-C3N4 powders into anhydrous ethanol, disperse by ultrasonic and then stir by magnetic stirring to obtain a sample, dry the sample in an oven, take it out and grind it thoroughly, put it into a crucible, and then put it into a muffle furnace and calcine it at 500℃ for 2h, and finally grind it thoroughly to obtain nano ZrO2-TiO2-g-C3N4 powder;

[0028] Among them, nano-TiO2 can only absorb ultraviolet light, so its utilization efficiency of solar energy is low. The photocatalytic efficiency of the material can be improved by compounding nano-ZrO2 and nano-g-C3N4.

[0029] Since the scale of nano ZrO2, nano TiO2 and nano g-C3N4 powders is within 100nm, which is much smaller than the wavelength of visible light, it will not cause too much change to the protective color; after the coating is dried, the nano material can form a network structure to increase the surface strength of the coating; nano ZrO2, nano TiO2 and nano g-C3N4 powders can also adhere to the surface of the film-forming material through a grafting reaction with dodecyltrimethoxysilane, which can increase the roughness of the surface of the film-forming material to achieve the purpose of improving the contact angle of the material.

[0030] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0031] The present invention discloses a red sandstone cultural relic anti-weathering coating and a preparation method thereof. After the red sandstone cultural relic is coated with the coating, the original color and appearance of the red sandstone cultural relic will not be covered, and the reinforced and repaired red sandstone cultural relic also has high surface hardness, high hydrophobicity, high air permeability, excellent acid resistance, salt resistance and other properties.

[0032] Dodecyltrimethoxysilane is used as the main film-forming substance. After coating, it has excellent alkyl waterproof properties and good compatibility with inorganic silicate matrix materials. Red sandstone powder is added. The red sandstone powder has the same texture as red sandstone cultural relics, has good compatibility, and will not change the color of the cultural relics. The composite nano-modifier and the red sandstone powder form a particle combination to form a composite pore structure, which helps to enhance the air permeability of the coating.

[0033] The addition of a salt crystallization inhibitor increases the saturation of salt that would otherwise crystallize on the surface of the red sandstone cultural relic. Under the capillary action of the pore-forming agent to create special pores, the soluble salt will be discharged from the cultural relic along with the water. This ensures that the coating has good compatibility, waterproofness, air permeability, wear resistance and other properties while improving the salt resistance of the material.

[0034] Furthermore, the present invention prepares three coatings containing pore-forming agents with different particle sizes by adding gelatin particles with different particle sizes into the coating, and prepares an anti-weathering coating with a gradient pore structure by a layered coating method, which greatly enhances the air permeability of the cultural relics while ensuring that the cultural relics have good waterproof properties; in addition, the special pore structure can drain moisture from the inside of the cultural relics through capillary action.

[0035] The present invention prepares nano ZrO2-TiO2-g-C3N4 powder by compounding nano zirconium dioxide, nano titanium dioxide and nano graphite phase carbon nitride, which can not only improve the photocatalytic efficiency of the material by compounding ZrO2 and g-C3N4, but also will not cause too much change to the protective color, and can also increase the surface strength of the coating. At the same time, by grafting reaction with dodecyltrimethoxysilane and adhering to the surface of the film-forming material, the roughness of the surface of the film-forming material can be improved, so as to achieve the purpose of improving the contact angle of the material.

[0036] By allowing nano ZrO2-TiO2-g-C3N4 powder to react with nano cellulose under the action of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, not only can the interface performance between the nano modified material and the aggregate be improved, and the dispersion effect of nano ZrO2-TiO2-g-C3N4 powder and nano cellulose be enhanced; it also has stronger anti-ultraviolet, antibacterial and anti-fouling capabilities; nano ZrO2-TiO2-g-C3N4 powder grafted on nano cellulose can improve the hydrophobicity of nano cellulose; nano ZrO2-TiO2-g-C3N4 powder grafted on nano cellulose can increase the roughness of nano cellulose, and after the coating is dried and hardened, the friction between the fiber and the coating is enhanced, and the toughness of the coating is improved through the bridging effect of the fiber. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0038] Figure 1 The infrared spectrum diagram of the infrared spectrum test after the anti-weathering coating of Experimental Examples 1-4 was applied to the sandstone cultural relics;

[0039] Figure 2 The contact angle of the red sandstone cultural relic after the anti-weathering coating of Experimental Examples 1-4 was applied to the sandstone cultural relic;

[0040] Figure 3 This is a test diagram of the moisture permeability coefficient after the anti-weathering coating of Experimental Examples 1-4 was applied to the sandstone cultural relics;

[0041] Figure 4 (a) is the mass loss rate of the weathering-resistant coatings of Experimental Examples 1-4 under different acid cycle times without coating, and with coating, Figure 4 (b) is the mass loss rate of the anti-weathering coating of Experimental Examples 1-4 under different acid cycle times;

[0042] Figure 5 (a) is the mass loss rate of the weathering-resistant coatings of uncoated and coated experimental examples 1-4 under different salt cycle times, Figure 5 (b) is the mass loss rate of the anti-weathering coating of Experimental Examples 1-4 under different salt cycle times. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments and drawings, but the present invention is not limited to the scope of the embodiments. The experimental methods in the following embodiments without specifying specific conditions are selected according to conventional methods and conditions, or according to the product instructions.

[0044] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0045] Example 1

[0046] A red sandstone cultural relic anti-weathering coating comprises the following components in parts by weight: 85-110 parts of anhydrous ethanol, 10-15 parts of a film-forming component, 0.5-1.5 parts of a salt crystallization inhibitor, 0.5-2 parts of a pore-forming agent, and 0.01-0.06 parts of a composite nano-modifier;

[0047] A method for preparing a red sandstone cultural relic anti-weathering coating comprises the following steps:

[0048] S1 prepares pore formers, film-forming components, salt crystallization inhibitors and composite nano-modifiers;

[0049] S2: adding the film-forming component, the salt crystallization inhibitor and the pore-forming agent into anhydrous ethanol and stirring to obtain solution A;

[0050] S3: adding the composite nano-modifier into solution A, dispersing by ultrasonic, and stirring to obtain the coating.

[0051] Wherein, the film-forming component includes dodecyltrimethoxysilane.

[0052] In some embodiments, the film-forming component includes dodecyl trimethoxysilane, red sandstone powder, and dodecylphenol polyoxyethylene ether. Preferably, the weight ratio of dodecyl trimethoxysilane, red sandstone powder, and dodecylphenol polyoxyethylene ether is 8-15:0.5-2.5:0.5-2. Dodecyl trimethoxysilane is the main film-forming substance, and dodecylphenol polyoxyethylene ether makes the mutually immiscible dodecyl trimethoxysilane and red sandstone powder form a stable emulsion.

[0053] In some embodiments, the salt crystallization inhibitor includes one or more of phosphocitric acid, aminoacetamide, and disodium octaborate tetrahydrate.

[0054] In some embodiments, the pore-forming agent includes gelatin particles, and the particle size of the gelatin particles is 400-1000 meshes. The gelatin particles are soaked in excess anhydrous ethanol, and after fully absorbing the organic solvent to swell, they are filtered to obtain the pore-forming agent.

[0055] Example 2

[0056] Based on the above embodiment, the preparation of the film-forming component comprises the following steps:

[0057] (1) preparing red sandstone powder;

[0058] The broken blocks of red sandstone are placed in an electric hot air drying oven and dried at 105±5°C. The broken blocks, corundum balls and water after drying are placed in a drum ball mill, wherein the weight ratio of the broken blocks of red sandstone: water: corundum balls is 1:1:8, and 0.5% acrylic resin of the amount of red sandstone is added as a dispersant, and wet grinding is performed at a speed of 120 revolutions per minute for 1.5 hours; after the grinding is completed, the ground mixture is filtered, and the residual solid is placed in an oven at 105±5°C to dry to a constant weight, and then the dried filter cake is fully dispersed by a pulverizer; and the dispersed red sandstone powder is sieved through a 600-mesh negative pressure to obtain red sandstone powder;

[0059] (2) preparing film-forming components;

[0060] Red sandstone powder and dodecylphenol polyoxyethylene ether were added to dodecyltrimethoxysilane, and the film-forming component was obtained after ultrasonic dispersion for 0.5 h and magnetic stirring for 0.5 h.

[0061] Example 3

[0062] Based on the above embodiment, the composite nano modifier includes the following components in parts by weight: 0.5-5 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, 0.01-0.5 parts of nano ZrO2-TiO2-g-C3N4 powder and 0.01-0.5 parts of nano cellulose.

[0063] Based on the above embodiment, the preparation of the composite nano modifier includes the following steps:

[0064] (1) Preparation of Nanocellulose

[0065] The nanocellulose is soaked in 2% sulfuric acid and heated at 120°C for 2 hours to remove hemicellulose and lignin to obtain a mixture; the mixture is filtered, and the solid residue is washed with deionized water until a neutral pH value is reached, and dried at 80°C to a constant weight to obtain the nanocellulose.

[0066] (2) Preparation of Nano ZrO2-TiO2-g-C3N4 Powder

[0067] According to the following weight ratio, 1.5 parts of nano ZrO2, 1.5 parts of nano TiO2 and 2 parts of nano g-C3N4 powder were added to 200 mL of anhydrous ethanol, and ultrasonically dispersed for 0.5 h and magnetically stirred for 0.5 h to obtain a sample;

[0068] The sample was placed in an oven at 40°C for drying, taken out and fully ground, then placed in a crucible and calcined in a muffle furnace at 500°C for 2h. After sufficient grinding, nano ZrO2-TiO2-g-C3N4 powder was obtained.

[0069] (3) Preparation of composite nano-modifier

[0070] γ-(2,3-epoxypropoxy)propyltrimethoxysilane was added to 100 mL of deionized water and stirred for 5 min; nano ZrO2-TiO2-g-C3N4 powder and nano cellulose were added, ultrasonically dispersed for 1 h, and stirred for 1 h to obtain a mixed suspension;

[0071] After the mixed suspension was stirred at room temperature at 500 rpm for 1 hour, the stirred suspension was poured into a hydrothermal reactor; the hydrothermal reactor was placed in an oven at 110°C for 8 hours; after the reaction was completed, the reactants were washed with deionized water and centrifuged 5 times, each time for 6 minutes;

[0072] After washing, the reactants were placed in an oven and dried at 105°C ± 5°C for 24 hours to obtain a composite nano-modifier.

[0073] Example 4

[0074] Based on the above embodiment, a red sandstone cultural relic anti-weathering coating includes, from bottom to top, a first coating, a second coating and a third coating, the pore-forming agent in the first coating includes gelatin particles with a particle size of r1, the pore-forming agent in the second coating includes gelatin particles with a particle size of r2, and the pore-forming agent in the third coating includes gelatin particles with a particle size of r3, r1>r2>r3.

[0075] On the basis of the above embodiment, a method for preparing a red sandstone cultural relic anti-weathering coating further comprises the following steps:

[0076] Repeat steps S1-S3 three times to obtain three coatings, the three coatings are respectively a first coating, a second coating and a third coating, the pore-forming agent in the first coating comprises gelatin particles with a particle size of r1, the pore-forming agent in the second coating comprises gelatin particles with a particle size of r2, and the pore-forming agent in the third coating comprises gelatin particles with a particle size of r3, r1>r2>r3;

[0077] The first coating, the second coating and the third coating are sequentially applied to the red sandstone artifacts.

[0078] In some embodiments, preferably, r1=400 mesh, r2=700 mesh, and r3=1000 mesh.

[0079] Example 5

[0080] On the basis of the above embodiment, a red sandstone cultural relic anti-weathering coating comprises the following components in parts by weight: 85-110 parts of anhydrous ethanol, 10-15 parts of film-forming components, 0.5-1.5 parts of salt crystallization inhibitor, 0.5-2 parts of pore-forming agent, and 0.01-0.06 parts of composite nano-modifier;

[0081] A method for preparing a red sandstone cultural relic anti-weathering coating comprises the following steps:

[0082] S1 prepares pore formers, film-forming components, salt crystallization inhibitors and composite nano-modifiers;

[0083] S2: adding the film-forming component, the salt crystallization inhibitor and the pore-forming agent into anhydrous ethanol and stirring to obtain solution A;

[0084] S3: adding the composite nano-modifier into solution A, dispersing by ultrasonic, and stirring to obtain the coating.

[0085] S4 repeats steps S1-S3 three times to obtain three coatings, the three coatings are respectively a first coating, a second coating and a third coating, the pore-forming agent in the first coating comprises gelatin particles with a particle size of r1, the pore-forming agent in the second coating comprises gelatin particles with a particle size of r2, and the pore-forming agent in the third coating comprises gelatin particles with a particle size of r3, r1>r2>r3;

[0086] S5 applies the first coating, the second coating and the third coating in sequence on the red sandstone cultural relic.

[0087] On the basis of Example 5, the anti-weathering coatings of Experimental Examples 1-4 were applied to sandstone cultural relics and then performance tests were performed.

[0088] Experimental Example 1

[0089] It includes 85 parts of anhydrous ethanol, 15 parts of film-forming components, 0.6 parts of salt crystallization inhibitor, 0.5 parts of pore-forming agent, and 0.03 parts of composite nano-modifier;

[0090] The weight ratio of dodecyl trimethoxysilane, red sandstone powder and dodecylphenol polyoxyethylene ether in the film-forming component is 10:2:0.5;

[0091] The weight ratio of aminoacetamide to sodium octaborate tetrahydrate in the salt crystallization inhibitor is 9:1;

[0092] The pore-forming agent has r1=400 mesh, r2=700 mesh, and r3=1000 mesh;

[0093] The weight ratio of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, nano ZrO2-TiO2-g-C3N4 powder and nano cellulose in the composite nano modifier is 4:0.05:0.02;

[0094] Experimental Example 2

[0095] It includes 90 parts of anhydrous ethanol, 10 parts of film-forming components, 1.2 parts of salt crystallization inhibitor, 0.7 parts of pore-forming agent, and 0.02 parts of composite nano-modifier;

[0096] The weight ratio of dodecyl trimethoxysilane, red sandstone powder and dodecylphenol polyoxyethylene ether in the film-forming component is 10:2.5:2.

[0097] The weight ratio of aminoacetamide to sodium octaborate tetrahydrate in the salt crystallization inhibitor is 9:1;

[0098] The pore-forming agent has r1=400 mesh, r2=700 mesh, and r3=1000 mesh;

[0099] The weight ratio of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, nano ZrO2-TiO2-g-C3N4 powder and nano cellulose in the composite nano modifier is 2:0.05:0.02;

[0100] Experimental Example 3

[0101] It includes 88 parts of anhydrous ethanol, 12 parts of film-forming components, 1 part of salt crystallization inhibitor, 0.7 parts of pore-forming agent, and 0.04 parts of composite nano-modifier;

[0102] The weight ratio of dodecyl trimethoxysilane, red sandstone powder and dodecylphenol polyoxyethylene ether in the film-forming component is 10:2:1;

[0103] The weight ratio of aminoacetamide and sodium octaborate tetrahydrate in the salt crystallization inhibitor is 9:1;

[0104] The pore-forming agent has r1=400 mesh, r2=700 mesh, and r3=1000 mesh;

[0105] The weight ratio of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, nano ZrO2-TiO2-g-C3N4 powder and nano cellulose in the composite nano modifier is 3:0.04:0.02;

[0106] Experimental Example 4

[0107] It includes 90 parts of anhydrous ethanol, 10 parts of film-forming components, 1 part of salt crystallization inhibitor, 0.9 parts of pore-forming agent, and 0.04 parts of composite nano-modifier;

[0108] The weight ratio of dodecyl trimethoxysilane, red sandstone powder and dodecylphenol polyoxyethylene ether in the film-forming component is 10:0.5:2;

[0109] The weight ratio of aminoacetamide and sodium octaborate tetrahydrate in the salt crystallization inhibitor is 8:2;

[0110] The pore-forming agent has r1=400 mesh, r2=700 mesh, and r3=1000 mesh;

[0111] The weight ratio of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, nano ZrO2-TiO2-g-C3N4 powder and nano cellulose in the composite nano modifier is 3:0.04:0.02;

[0112] (1) After the anti-weathering coatings of Experimental Examples 1-4 were applied to the sandstone cultural relics, surface hardness and color difference performance tests were performed. The test results are shown in Table 1;

[0113] Table 1

[0114]

[0115] As shown in Table 1, after being coated with the coating of the present invention, the hardness can be improved. This is because gelatin particles of different particle sizes are sequentially coated on the red sandstone cultural relics, so that the coating has a gradient pore structure after drying, which makes the cultural relics have good waterproof properties and greatly enhances the air permeability of the cultural relics; and the special pore structure can discharge the internal moisture of the cultural relics to the outside through capillary action. Therefore, the coating of the present invention not only does not cover the original color morphology of the red sandstone cultural relics, but also the reinforced and repaired red sandstone cultural relics also have high surface hardness.

[0116] (2) After applying the anti-weathering coating of Experimental Examples 1-4 to the sandstone cultural relics, an infrared spectrum test was performed. Figure 1 As shown, Figure 1 Medium 3318cm -1 The broad absorption peak at 2972cm is related to the stretching and bending vibration of -OH in the solvent anhydrous ethanol. -1 and 1379cm -1 The absorption peak at 2926cm is the stretching vibration of -CH3, while -1 The absorption peak at is the stretching vibration of -CH2-. 12 H 25 The group has good hydrophobicity. When the coating is cross-linked and cured inside the red sandstone, -C 12 H 25 The groups are closely arranged on the surface of red sandstone, giving it good hydrophobic properties; the absorption peaks at 1087cm-1 and 1046cm-1 are caused by the Si-O-Si symmetrical bending vibration, while the absorption peak at 633cm-1 is caused by the Si-O bending vibration.

[0117] (3) After applying the anti-weathering coating of Experimental Examples 1-4 to the sandstone cultural relics, the contact angle test of the cultural relics was performed, such as Figure 2 As shown, the contact angles of Experimental Examples 1-4 are 135.3°, 116.7°, 123.0°, and 123.8°, respectively.

[0118] The sandstone artifacts without anti-weathering coating were completely wetted by Figure 2 It can be seen that the coatings of Experimental Examples 1-4 have good waterproof properties.

[0119] (4) After applying the anti-weathering coating of Experimental Examples 1-4 to the sandstone cultural relics, a moisture permeability test was performed. Figure 3 As shown, after the anti-weathering coating is applied to the sandstone cultural relics, the moisture permeability coefficient is reduced. The coating of the present invention blocks the penetration of water vapor. Figure 3 In the embodiment, the moisture permeability coefficient decreases less, which indicates that the coating still has good moisture permeability after coating, and the present invention improves the air permeability of the material from multiple angles.

[0120] (5) After applying the anti-weathering coatings of Experimental Examples 1-4 to sandstone cultural relics, an acid resistance test was performed. Figure 4 As shown, Figure 4 (a) is the mass loss rate of the weathering-resistant coatings of Experimental Examples 1-4 under different acid cycle times without coating, and with coating, Figure 4 (b) is the mass loss rate of the anti-weathering coating of Experimental Examples 1-4 under different acid cycle times. Figure 4 It can be seen that the anti-weathering coatings of Experimental Examples 1-4 have good acid resistance.

[0121] (6) After applying the anti-weathering coatings of Experimental Examples 1-4 to sandstone cultural relics, a salt resistance test was performed. Figure 5 As shown in FIG. 1 , after the anti-weathering coatings of Experimental Examples 1-4 were applied to the sandstone cultural relics, a salt resistance test was performed. Figure 5 As shown, Figure 5 (a) is the mass loss rate of the weathering-resistant coatings of uncoated and coated experimental examples 1-4 under different salt cycle times, Figure 5 (b) is the mass loss rate of the anti-weathering coating of Experimental Examples 1-4 under different salt cycle times. Figure 5 It can be seen that the anti-weathering coatings of Experimental Examples 1-4 have good salt resistance.

[0122] Comparative Example 1

[0123] On the basis of the above embodiment, a red sandstone cultural relic anti-weathering coating comprises 85 parts of anhydrous ethanol, 15 parts of film-forming components, 1 part of salt crystallization inhibitor, 0.5 parts of pore-forming agent, and 0.03 parts of composite nano-modifier;

[0124] The weight ratio of dodecyl trimethoxysilane, red sandstone powder and dodecylphenol polyoxyethylene ether in the film-forming component is 10:2:0.5;

[0125] The weight ratio of aminoacetamide and sodium octaborate tetrahydrate in the salt crystallization inhibitor is 9:1; and the r1 of the pore-forming agent is 400 meshes.

[0126] The weight ratio of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, nano ZrO2-TiO2-g-C3N4 powder and nano cellulose in the composite nano modifier is 4:0.05:0.02.

[0127] A method for preparing a red sandstone cultural relic anti-weathering coating comprises the following steps:

[0128] S1 prepares pore formers, film-forming components, salt crystallization inhibitors and composite nano-modifiers;

[0129] S2: adding the film-forming component, the salt crystallization inhibitor and the pore-forming agent into anhydrous ethanol and stirring to obtain solution A;

[0130] S3: adding the composite nano-modifier into solution A, dispersing by ultrasonic, and stirring to obtain the coating.

[0131] S4 will be applied on red sandstone artifacts.

[0132] Comparative Example 2

[0133] On the basis of Experimental Example 1, Comparative Example 2 includes 85 parts of anhydrous ethanol, 50 parts of film-forming components, 0.1 parts of salt crystallization inhibitor, 0.1 parts of pore former, and 5 parts of composite nano modifier;

[0134] The weight ratio of dodecyl trimethoxysilane, red sandstone powder and dodecylphenol polyoxyethylene ether in the film-forming component is 10:2:0.5;

[0135] The weight ratio of aminoacetamide to sodium octaborate tetrahydrate in the salt crystallization inhibitor is 9:1;

[0136] The pore-forming agent has r1=400 mesh, r2=700 mesh, and r3=1000 mesh;

[0137] The weight ratio of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, nano ZrO2-TiO2-g-C3N4 powder and nano cellulose in the composite nano modifier is 4:0.05:0.02;

[0138] Comparative Example 3

[0139] On the basis of Experimental Example 1, Comparative Example 3 includes 85 parts of anhydrous ethanol, 15 parts of film-forming components, 1 part of a salt crystallization inhibitor, 0.5 parts of a pore former, and 0.03 parts of a composite nano-modifier;

[0140] Wherein, the film-forming component includes an organic silicon resin material modified by graphene oxide;

[0141] The weight ratio of aminoacetamide to sodium octaborate tetrahydrate in the salt crystallization inhibitor is 9:1;

[0142] The pore-forming agent has r3 = 400 mesh, r2 = 700 mesh, and r1 = 1000 mesh;

[0143] The weight ratio of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, nano ZrO2-TiO2-g-C3N4 powder and nano cellulose in the composite nano modifier is 4:0.05:0.02;

[0144] Comparative Example 4

[0145] On the basis of Experimental Example 1, Comparative Example 4 includes 85 parts of anhydrous ethanol, 15 parts of film-forming components, 1 part of a salt crystallization inhibitor, 0.5 parts of a pore-forming agent, and 0.03 parts of a composite nano-modifier;

[0146] The weight ratio of dodecyl trimethoxysilane, red sandstone powder and dodecylphenol polyoxyethylene ether in the film-forming component is 10:2:0.5;

[0147] The weight ratio of aminoacetamide to sodium octaborate tetrahydrate in the salt crystallization inhibitor is 9:1;

[0148] The pore-forming agent has r3 = 400 mesh, r2 = 700 mesh, and r1 = 1000 mesh;

[0149] The composite nano modifier comprises 20-60 parts of nano silicon oxide, 20-60 parts of nano zirconium oxide, 20-60 parts of nano graphene oxide, 70-90 parts of hexamethylene diisocyanate trimer and 10-30 parts of propylene glycol methyl ether acetate.

[0150] After the anti-weathering coatings of Comparative Examples 1-4 were applied to the sandstone cultural relics, performance tests were conducted, and the test results are shown in Table 2;

[0151] Table 2

[0152]

[0153] After the anti-weathering coatings of Comparative Examples 1-4 were applied to the sandstone cultural relics, performance tests were conducted. Among them, compared with the present invention, Comparative Example 1 did not obtain three coatings, and the first coating, the second coating and the third coating were applied to the red sandstone cultural relics in sequence. It can be seen from Tables 1 and 2 that compared with Experimental Example 1, the air permeability of the coating of Comparative Example 1 is worse than that of Experimental Example 1. The component ratio of Comparative Example 2 is outside the protection scope of the present invention, and all aspects of the performance of Comparative Example 2 are worse than those of Experimental Example 1; the film-forming component of Comparative Example 3 is a graphene oxide modified silicone resin material, and the water resistance and air permeability of Comparative Example 3 are consistent with those of Experimental Example 1, but the salt resistance of Comparative Example 3 is poor, and the original color of the cultural relics is covered, so it is not conducive to use in cultural relic protection.

[0154] The composite nano modifier of Comparative Example 4 is inconsistent with the composite nano modifier components of Experimental Example 1. The strength of the coating of Comparative Example 4 is worse than that of the coating of Experimental Example 1, and the toughness and salt resistance of the coating of Comparative Example 4 are also poor. Therefore, the protective effect on cultural relics is poor.

[0155] In summary, the anti-weathering coating of the present invention not only does not cover the original color and morphology of the red sandstone cultural relics, but also the reinforced and repaired red sandstone cultural relics also have high surface hardness, high hydrophobicity, high air permeability, excellent acid resistance, salt resistance and other properties.

[0156] The above descriptions are only some specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A red sandstone cultural relic anti-weathering coating, characterized in that: The invention comprises the following components in parts by weight: 85-110 parts of anhydrous ethanol, 10-15 parts of film-forming components, 0.5-1.5 parts of salt crystallization inhibitor, 0.5-2 parts of pore-forming agent and 0.01-0.06 parts of composite nano-modifier; the film-forming component comprises dodecyltrimethoxysilane and the pore-forming agent comprises gelatin particles.

2. The anti-weathering coating for red sandstone cultural relics according to claim 1, characterized in that: The film-forming components also include red sandstone powder and dodecylphenol polyoxyethylene ether.

3. The anti-weathering paint for red sandstone cultural relics according to claim 2, characterized in that: The weight ratio of dodecyl trimethoxysilane, red sandstone powder and dodecylphenol polyoxyethylene ether is 8-15: 0.5-2.5：0.5-2。 4. The anti-weathering paint for red sandstone cultural relics according to claim 1, characterized in that: The composite nano modifier comprises the following components in parts by weight: 0.5-5 parts of gamma-(2,3-epoxypropoxy)propyltrimethoxysilane, 0.01-0.5 parts of nano ZrO2-TiO2-g-C3N4 powder and 0.01-0.5 parts of nano cellulose.

5. The anti-weathering paint for red sandstone cultural relics according to claim 1, characterized in that: The particle size of gelatin particles is 400-1000 mesh.

6. The anti-weathering paint for red sandstone cultural relics according to claim 1, characterized in that: The salt crystallization inhibitor includes one or more of phosphocitric acid, aminoacetamide, and disodium octaborate tetrahydrate.

7. The anti-weathering paint for red sandstone cultural relics according to claim 1, characterized in that: The invention comprises a first coating, a second coating and a third coating, which are used to be sequentially coated on red sandstone cultural relics. The pore-forming agent in the first coating comprises gelatin particles with a particle size of r1, the pore-forming agent in the second coating comprises gelatin particles with a particle size of r2, and the pore-forming agent in the third coating comprises gelatin particles with a particle size of r3, and r1>r2>r3.

8. A method for preparing a red sandstone cultural relic anti-weathering coating, characterized in that: The coating according to any one of claims 1 to 6 comprises the following steps: S1 prepares pore formers, film-forming components, salt crystallization inhibitors and composite nano-modifiers; S2: adding the film-forming component, the salt crystallization inhibitor and the pore-forming agent into anhydrous ethanol and stirring to obtain solution A; S3: adding the composite nano-modifier into solution A, dispersing by ultrasonic, and stirring to obtain the coating.

9. The method for preparing a red sandstone cultural relic anti-weathering coating according to claim 8, characterized in that: The following steps are also included: Repeat steps S1-S3 three times to obtain three coatings, the three coatings are respectively a first coating, a second coating and a third coating, the pore-forming agent in the first coating comprises gelatin particles with a particle size of r1, the pore-forming agent in the second coating comprises gelatin particles with a particle size of r2, and the pore-forming agent in the third coating comprises gelatin particles with a particle size of r3, r1>r2>r3; The first coating, the second coating and the third coating are used to be sequentially applied on the red sandstone artifacts.

10. The method for preparing a red sandstone cultural relic anti-weathering coating according to claim 8, characterized in that: In S1, the film-forming components include dodecyltrimethoxysilane, red sandstone powder, and dodecylphenol polyoxyethylene ether. The red sandstone powder and dodecylphenol polyoxyethylene ether are added to dodecyltrimethoxysilane, and the film-forming components are obtained by stirring after ultrasonic dispersion.

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