An anti-permeation aluminum-based nanoceramic coating, a preparation method and application thereof

Abstract

This invention belongs to the field of coating technology, specifically relating to an impermeable aluminum-based nano-ceramic coating, comprising the following components by weight: 80-90 parts solvent-based acrylic resin, 3-5 parts modified Al2O3 nanofibers, 3-5 parts nano-ceramic powder, 1-3 parts nano-titanium dioxide hybrid material, 1-3 parts organosilicon monomer, 1-2 parts perfluoropolyether, 0.2-0.8 parts initiator, 0.2-0.8 parts matting agent, and 0-1 parts additives; wherein, the nano-titanium dioxide hybrid material is a composite of titanium dioxide / dopamine hydrochloride particles and a selectively permeable membrane; the coating provided by this invention has multifunctional repair capabilities and can be applied to the repair and reinforcement of walls in historical buildings.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, specifically relating to an anti-permeability aluminum-based nano-ceramic coating, its preparation method, and its application. Background Technology

[0002] The restoration of building exterior walls typically involves demolishing and rebuilding the walls. However, for buildings with preservation and research value, demolition and rebuilding not only destroy the building's historical information but also negate its protective significance. Therefore, the restoration of this type of building exterior wall must fully consider the historical value of the building, adhering to the principle of "restoring the old as it was." Under the condition of not damaging the original wall foundation and preserving some of the original historical appearance of the walls, the restoration of the old walls should be made more stable, durable, and retain a more complete historical appearance.

[0003] Moisture intrusion is a significant cause of damage to historical buildings. The walls of historical buildings often suffer from common problems such as dampness, mold, and water seepage, which are difficult to eradicate effectively. This is because capillary cracks and potential differences exist within the walls, allowing moisture to continuously penetrate from the outside, fostering fungal growth, creating an expansion-fracture effect, and gradually causing damage and contamination. Coatings used for the protection and restoration of historical building walls need to possess the following characteristics: 1. Good adhesion to the substrate; 2. Good resistance to light, heat, mold, and seepage, as well as good resistance to natural damage; 3. Colorless with a refractive index similar to transparent materials. Due to the unique nature of historical building wall restoration, current technologies generally rely on single-function restoration products, such as applying hardeners, epoxy mortar, reinforcing agents, or seepage-proofing agents to the wall surface. There is a lack of universally applicable specialized coatings suitable for the protection and restoration of historical building walls. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides an impermeable aluminum-based nano-ceramic coating and its preparation method, which has good adhesion to the substrate and good resistance to natural damage, and is suitable for the repair of cracks in ancient building walls and the protection of wall surfaces.

[0005] The technical solution of the present invention is as follows:

[0006] This invention provides an impermeable aluminum-based nano-ceramic coating, comprising the following components by weight: 80-90 parts solvent-based acrylic resin, 3-5 parts modified Al2O3 nanofibers, 3-5 parts nano-ceramic powder, 1-3 parts nano-titanium dioxide hybrid material, 1-3 parts organosilicon monomer, 1-2 parts perfluoropolyether, 0.2-0.8 parts initiator, 0.2-0.8 parts matting agent, and 0-1 parts additives;

[0007] Among them, the nano-titanium dioxide hybrid material is a composite of titanium dioxide / dopamine hydrochloride particles and a selectively permeable membrane.

[0008] Further, the solvent-based acrylic resin is a mixture of at least one of methyl methacrylate, glycidyl methacrylate, or Primal B-60A with epoxy acrylate.

[0009] Furthermore, the modified Al2O3 nanofibers are obtained by grafting and modifying the surface of Al2O3 nanofibers with polymethacrylic acid or polyacrylamide.

[0010] Furthermore, the selectively permeable membrane is a block polymer copolymerized from nonpolar monomers and polar monomers; the nonpolar monomers include one or more of ethylene, styrene, propylene or isocyanates, and the polar monomers include one or more of polyethylene glycol, methacrylic acid or o-styrene sulfonic acid.

[0011] Furthermore, the preparation method of the nano-titanium dioxide hybrid material is as follows:

[0012] (1) Dopamine hydrochloride was dispersed in a solvent, and a titanium-containing precursor solution was added and stirred at room temperature. Then the temperature was raised to 100-120℃ and stirred. After centrifugation, washing and drying, titanium dioxide / dopamine hydrochloride functional particles were obtained.

[0013] (2) Then disperse the titanium dioxide / dopamine hydrochloride functional particles in the dispersant aqueous solution and sonicate them, and let them stand to remove bubbles;

[0014] (3) Titanium dioxide / dopamine hydrochloride functional particles and selectively permeable membrane are placed in an organic solvent and a carboxyl activator is added. Ultrasonic fusion is performed to graft the titanium dioxide / dopamine hydrochloride functional particles onto the blocks of the selectively permeable membrane to obtain nano-titanium dioxide hybrid material.

[0015] Further, in step (1), the solvent is water, methanol, ethanol, or a mixture thereof; the titanium-containing precursor solution is titanium trichloride, titanium tetrachloride, tetrabutyl titanate, isobutyl titanate, metatitanic acid, or a mixture thereof; in step (2), the dispersant is a polymeric dispersant; and in step (3), the organic solvent is N,N-dimethylformamide, N-methyl-2-pyrrolidone, tetrahydrofuran (THF), or a mixture thereof.

[0016] Furthermore, the initiator is ammonium persulfate or tert-butanol peroxide, and the matting agent is DA-60, wax, or fumed silica.

[0017] Furthermore, the additives are additives required for coatings, including leveling agents, dispersants, or pH adjusters.

[0018] This invention also provides a method for preparing an impermeable aluminum-based nano-ceramic coating, comprising the following steps:

[0019] S1: Modified Al2O3 nanofibers and nano-ceramic powders are dispersed in an organic solvent, and then ultrasonically treated after adding a dispersant;

[0020] S2. Solvent-based acrylic resin and nano-titanium dioxide hybrid material are added to an aqueous solution containing matting agent and initiator, and a stable emulsion is formed using a homogenizer;

[0021] S3. Add the stable emulsion obtained in step S2 to the mixed solution obtained in step S1, add perfluoropolyether and organosilicon monomer, stir the reaction thoroughly until microcapsules are formed in the solution, and adjust the pH of the system to neutral using a pH adjuster after the reaction is completed.

[0022] S4. Add the solution to the paint sprayer and spray it into the container under high pressure to plasticize the microcapsules and form a microcapsule paint with droplet shape.

[0023] This invention also provides an application of an impermeable aluminum-based nano-ceramic coating in the repair and reinforcement of brick and stone masonry surfaces in historical buildings, which can be used to prevent the deterioration and pollution of brick and stone masonry surfaces, as well as dampness, mold, and water seepage in the walls.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. This invention is a multi-functional coating developed for the repair and reinforcement of walls in historical buildings. The solvent-based acrylic resin used in this invention is a mixture of at least one of methyl methacrylate, glycidyl methacrylate, or Primal B-60A and epoxy acrylate. At least one of methyl methacrylate, glycidyl methacrylate, or Primal B-60A is soluble in the solvent. After the solvent evaporates, the polymer molecular chains come into close contact, achieving curing and good adhesion to the substrate. The polymer molecular chains can be broken apart again to form a liquid, achieving reversible cleaning of the coating. At the same time, the addition of epoxy acrylate can overcome the lack of stability of methyl methacrylate, glycidyl methacrylate, or Primal B-60A under long-term light exposure. Through the cross-linking effect of epoxy acrylate and the above polymer molecules, the final film of the coating has a small shrinkage rate, is not prone to expansion or shrinkage cracking, and is not prone to powdering even under long-term light exposure or high temperature environment, thus exhibiting excellent stability.

[0026] 2. The coating of this invention incorporates a nano-titanium dioxide hybrid material, which is a fusion system of titanium dioxide / dopamine hydrochloride particles and a selectively permeable membrane. The titanium dioxide / dopamine hydrochloride particles endow the hybrid material with self-cleaning ability and protect the polymer matrix from free radical effects during UV irradiation, thereby improving the performance stability and service life of the final coating. The amino groups of dopamine in the modified nano-titanium dioxide are grafted onto the selectively permeable membrane through a condensation reaction, increasing the water sensitivity of the dopamine-modified polymer and improving the impermeability and stability of the coating after application. The fused selectively permeable membrane can prevent water, sulfur dioxide, hydrogen sulfide, and oxygen from penetrating and causing damage, and its coefficient of thermal expansion is close to that of cultural relics. At the same time, the nano-titanium dioxide hybrid material also has good antibacterial properties, preventing microbial damage. Furthermore, by modifying the nano-titanium dioxide, the problem of its antibacterial performance being significantly reduced under the conditions of high porosity and roughness of historical building walls is avoided.

[0027] 3. The grafted Al2O3 nanofibers in this invention are controllable, giving full play to the advantages of Al2O3 nanofibers, so that they can achieve the effects of coating reinforcement and toughening with low addition amount; the addition of organosilicon monomers and perfluoropolyethers can improve the waterproof and impermeable performance of the coating.

[0028] 4. The coating provided by this invention has multiple functions, including sealing and protecting the surface of brick and stone materials, preventing seepage, delaying weathering, and inhibiting microorganisms. Moreover, the coating is colorless after film formation, and its refractive index is similar to that of transparent materials, so it will not change the surface color and texture, and will not affect the appearance of cultural relics and buildings. Attached Figure Description

[0029] Figure 1 This is a schematic diagram illustrating the specific application of the anti-permeability aluminum-based nano-ceramic coating in Example 5. Detailed Implementation

[0030] The present invention will be further described below with reference to preferred embodiments. The endpoints and any values ​​of the ranges disclosed in the present invention are not limited to the precise ranges or values. These ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed herein.

[0031] Example 1

[0032] This embodiment provides a seepage-resistant aluminum-based nano-ceramic coating, comprising the following components in parts by weight:

[0033] 80 parts solvent-based acrylic resin, 5 parts modified Al2O3 nanofibers, 5 parts nano-ceramic powder, 3 parts nano-titanium dioxide hybrid material, 3 parts organosilicon monomer, 2 parts perfluoropolyether, 0.5 parts ammonium persulfate, 0.5 parts fumed silica and 1 part additives, the additives being leveling agents, dispersants and / or pH adjusters;

[0034] Solvent-based acrylic resin is a mixture of methyl methacrylate and epoxy acrylate, with a ratio of methyl methacrylate to epoxy acrylate of 6:4;

[0035] The preparation method of modified Al2O3 nanofibers is as follows: under stirring conditions, silane coupling agent is dissolved in water, then Al2O3 nanoparticles and polymethyl methacrylate are added, then an emulsifying dispersant is added, and after the nanoparticles are fully dispersed, they are ultrasonically dispersed for 15-20 minutes, and then filtered and dried to obtain polymethyl methacrylate grafted modified Al2O3 nanoparticles.

[0036] The nano-titanium dioxide hybrid material is a composite of titanium dioxide / dopamine hydrochloride particles and a selectively permeable membrane; the selectively permeable membrane is a block polymer copolymerized from non-polar and polar monomers; in this embodiment, the non-polar monomer is styrene, and the polar monomer includes polyethylene glycol; the preparation method of the nano-titanium dioxide hybrid material is as follows:

[0037] (1) Dopamine hydrochloride was dispersed in water and titanium tetrachloride solution was added and stirred at room temperature. Then the temperature was raised to 100℃ and stirred. After centrifugation, washing and drying, titanium dioxide / dopamine hydrochloride functional particles were obtained.

[0038] (2) The titanium dioxide / dopamine hydrochloride functional particles were then dispersed in an aqueous solution containing styrene-maleic anhydride copolymer as a dispersant and ultrasonically treated, and then allowed to stand to remove bubbles.

[0039] (3) Titanium dioxide / dopamine hydrochloride functional particles and selectively permeable membranes were placed in N,N-dimethylformamide, and N,N-dicyclohexylcarbodiimide was added as a carboxyl activator. The mixture was ultrasonically fused for 30-40 minutes to graft the titanium dioxide / dopamine hydrochloride functional particles onto the blocks of the selectively permeable membrane to obtain nano-titanium dioxide hybrid materials.

[0040] Example 2

[0041] This embodiment provides a seepage-resistant aluminum-based nano-ceramic coating, comprising the following components in parts by weight:

[0042] 90 parts solvent-based acrylic resin, 3 parts modified Al2O3 nanofibers, 3 parts nano-ceramic powder, 1 part nano-titanium dioxide hybrid material, 1 part organosilicon monomer, 1 part perfluoropolyether, 0.8 parts peroxytert-butanol, 0.2 parts DA-60, where DA-60 is an acrylic polymer;

[0043] The solvent-based acrylic resin is a mixture of Primal B-60A and epoxy acrylate, with a ratio of 5:5 between Primal B-60A and epoxy acrylate.

[0044] The preparation method of modified Al2O3 nanofibers is as follows: under stirring conditions, silane coupling agent is dissolved in water, then Al2O3 nanoparticles and polyacrylamide monomer are added, then emulsifying dispersant is added, and after the nanoparticles are fully dispersed, ultrasonic dispersion is performed for 15-20 minutes, and then filtered and dried to obtain polyacrylamide acid grafted modified Al2O3 nanoparticles.

[0045] The nano-titanium dioxide hybrid material is a composite of titanium dioxide / dopamine hydrochloride particles and a selectively permeable membrane; the selectively permeable membrane is a block polymer copolymerized from non-polar and polar monomers; in this embodiment, the non-polar monomers include ethylene and propylene, and the polar monomer is methacrylic acid; the preparation method of the nano-titanium dioxide hybrid material is as follows:

[0046] (1) Dopamine hydrochloride was dispersed in methanol, and tetrabutyl titanate was added and stirred at room temperature. Then the temperature was raised to 120°C and stirred. After centrifugation, washing and drying, titanium dioxide / dopamine hydrochloride functional particles were obtained.

[0047] (2) The titanium dioxide / dopamine hydrochloride functional particles are then dispersed in an aqueous solution containing polyacrylamide as a dispersant and ultrasonically treated, and then allowed to stand to remove bubbles.

[0048] (3) Titanium dioxide / dopamine hydrochloride functional particles and selectively permeable membranes were placed in N-methyl-2-pyrrolidone, and N,N-dicyclohexylcarbodiimide was added as a carboxyl activator. The mixture was ultrasonically fused for 30-40 minutes to graft the titanium dioxide / dopamine hydrochloride functional particles onto the blocks of the selectively permeable membrane to obtain nano-titanium dioxide hybrid materials.

[0049] Example 3

[0050] This embodiment provides a seepage-resistant aluminum-based nano-ceramic coating, comprising the following components in parts by weight:

[0051] 85 parts solvent-based acrylic resin, 4 parts modified Al2O3 nanofibers, 4 parts nano-ceramic powder, 2 parts nano-titanium dioxide hybrid material, 2 parts organosilicon monomer, 1 part perfluoropolyether, 0.2 parts ammonium persulfate, 0.8 parts wax (which may be polyethylene wax, polypropylene wax, or polytetrafluoroethylene wax), and 1 part additive, which may be a leveling agent, dispersant, and / or pH adjuster.

[0052] Solvent-based acrylic resin is a mixture of glycidyl methacrylate and epoxy acrylate, with a ratio of glycidyl methacrylate to epoxy acrylate of 6:4.

[0053] The preparation method of modified Al2O3 nanofibers is as follows: under stirring conditions, silane coupling agent is dissolved in water, then Al2O3 nanoparticles and polyacrylamide monomer are added, then emulsifying dispersant is added, and after the nanoparticles are fully dispersed, ultrasonic dispersion is performed for 15-20 minutes, and then filtered and dried to obtain polyacrylamide acid grafted modified Al2O3 nanoparticles.

[0054] The nano-titanium dioxide hybrid material is a composite of titanium dioxide / dopamine hydrochloride particles and a selectively permeable membrane; the selectively permeable membrane is a block polymer copolymerized from nonpolar and polar monomers; in this embodiment, the nonpolar monomer is isocyanate, and the polar monomer is o-styrene sulfonic acid; the preparation method of the nano-titanium dioxide hybrid material is as follows:

[0055] (1) Dopamine hydrochloride was dispersed in ethanol, and metatitanic acid was added and stirred at room temperature. Then the temperature was raised to 110℃ and stirred. After centrifugation, washing and drying, titanium dioxide / dopamine hydrochloride functional particles were obtained.

[0056] (2) Then disperse the titanium dioxide / dopamine hydrochloride functional particles in an aqueous solution containing sodium polyacrylate as a dispersant and sonicate them, and let them stand to remove bubbles.

[0057] (3) Titanium dioxide / dopamine hydrochloride functional particles and selectively permeable membranes were placed in tetrahydrofuran, and N,N-dicyclohexylcarbodiimide was added as a carboxyl activator. The mixture was ultrasonically fused for 30-40 minutes to graft the titanium dioxide / dopamine hydrochloride functional particles onto the blocks of the selectively permeable membrane to obtain nano-titanium dioxide hybrid materials.

[0058] Example 4

[0059] This embodiment provides a method for preparing an impermeable aluminum-based nano-ceramic coating, comprising the following steps:

[0060] S1: The modified Al2O3 nanofibers and nano-ceramic powders are dispersed in an organic solvent, and then ultrasonically treated after the dispersant is added. In this embodiment, the organic solvent is N,N-dimethylformamide, N-methyl-2-pyrrolidone, tetrahydrofuran (THF), or a mixture thereof. The dispersant can be a caprolactone polyol-polyethyleneimine block copolymer type dispersant, an acrylate polymer type dispersant, polyurethane, a polymer polyether, or a polyester type polymer dispersant, etc. The mass ratio of the modified Al2O3 nanofibers to the nano-ceramic powders is 1:1.

[0061] S2. Solvent-based acrylic resin and nano-titanium dioxide hybrid material are added to an aqueous solution containing matting agent and initiator, and a stable emulsion is formed using a homogenizer;

[0062] S3. Add the stable emulsion obtained in step S2 to the mixed solution obtained in step S1, add perfluoropolyether and organosilicon monomer, stir the reaction thoroughly until microcapsules are formed in the solution, and adjust the pH of the system to neutral using a pH adjuster after the reaction is completed.

[0063] S4. Add the solution to the paint sprayer and spray it into the container under high pressure. This plasticizes the microcapsules to form droplet-shaped microcapsule paint. The droplet-shaped microcapsules can better penetrate into the wall that needs to be repaired during the paint application process.

[0064] Example 5

[0065] In this embodiment, the impermeable aluminum-based nano-ceramic coating is applied to the repair and reinforcement of brick and stone masonry surfaces of historical buildings. Pre-treatment before coating: remove sand, dust, and other contaminants from the wall surface; the surface must be free of water and oil. Coating treatment: mix 4 parts tap water with the coating of this invention, stir manually / by machine for 2 minutes, and let stand for 15-20 minutes. Application: spray or roll the coating onto the surface, wetting the surface with the coating. Apply 1-2 coats to avoid omissions. If two coats are required, wait 3-5 minutes between the first and second coats. Air drying at room temperature: the air drying time depends on the ambient temperature and humidity; ensure the surface is completely dry. The treated surface must not come into contact with water during the drying process.

[0066] like Figure 1 As shown, when the impermeable aluminum-based nano-ceramic coating of Example 1 is applied to the surface of building masonry, it can be seen that the sprayed area has less water seepage compared to the uncoated area, and can achieve a greater degree of impermeability.

[0067] The final coating layer samples were tested for light transmittance, haze, and hardness (glass surface). The final test results are shown in Table 1 below.

[0068]

[0069] In summary, the impermeable aluminum-based nano-ceramic coating prepared in this application exhibits excellent performance, including water and dirt repellency, maintaining substrate cleanliness over a long period; strong sealing properties, anti-aging, and a highly dense, cross-linked film that effectively blocks oxygen and water molecules; water resistance, UV aging resistance, and acid and alkali resistance; high hardness, being an inorganic coating, making it wear-resistant and scratch-resistant; and high adhesion. It forms chemical bonds with the substrate, achieving ISO 0 (highest level) adhesion.

[0070] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. An anti-permeation aluminum-based nanoceramic coating, characterized in that, The composition comprises the following components by weight: 80-90 parts of solvent type acrylic resin, 3-5 parts of modified Al2O3 nanofiber, 3-5 parts of nanoceramic powder, 1-3 parts of nanometer titanium dioxide hybrid material, 1-3 parts of silicone monomer, 1-2 parts of perfluoropolyether, 0.2-0.8 parts of initiator, 0.2-0.8 parts of matting agent and 0-1 parts of auxiliary agent; The nanometer titanium dioxide hybrid material is a composite of titanium dioxide / dopamine hydrochloride particles and a block polymer copolymerized from polar monomers and non-polar monomers; the solvent type acrylic resin is a mixture of at least one of methyl methacrylate and glycidyl methacrylate and epoxy acrylate; and the modified Al2O3 nanofiber is obtained by grafting modification of the surface of Al2O3 nanofiber with polymethyl methacrylate or polyacrylamide.

2. The anti-permeation aluminum-based nanoceramic coating according to claim 1, characterized in that: The non-polar monomers include one or more than two of ethylene, styrene, propylene or isocyanate, and the polar monomers include one or a combination of two of polyethylene glycol and methacrylic acid.

3. The anti-permeation aluminum-based nanoceramic coating according to claim 1, characterized in that: The preparation method of the nanometer titanium dioxide hybrid material is as follows: (1) Dopamine hydrochloride is added to a solvent and dispersed uniformly, and then a titanium-containing precursor solution is added and stirred to react at room temperature, and then the temperature is raised to 100-120°C for stirring to react, and then centrifugation, washing and drying are performed to obtain titanium dioxide / dopamine hydrochloride functional particles; (2) The titanium dioxide / dopamine hydrochloride functional particles are dispersed in an aqueous solution of a dispersant and subjected to ultrasonic treatment, and then left to stand for defoaming; (3) The titanium dioxide / dopamine hydrochloride functional particles treated in step (2) and a block polymer copolymerized from polar monomers and non-polar monomers are placed in an organic solvent, a carboxyl activator is added, ultrasonic fusion is performed to graft the titanium dioxide / dopamine hydrochloride functional particles to the blocks of the block polymer to obtain the nanometer titanium dioxide hybrid material.

4. The anti-permeation aluminum-based nanoceramic coating according to claim 3, characterized in that: The solvent in step (1) is water, methanol, ethanol or a mixture thereof; the titanium-containing precursor solution is titanium trichloride, titanium tetrachloride, n-butyl titanate, isobutyl titanate, metatitanic acid or a mixture thereof; the dispersant in step (2) is a high-molecular polymer dispersant; and the organic solvent in step (3) is N,N-dimethylformamide, N-methyl-2-pyrrolidone, tetrahydrofuran (THF) or a mixture thereof.

5. The anti-permeation aluminum-based nanoceramic coating according to claim 1, characterized in that: The initiator is ammonium persulfate or tert-butyl hydroperoxide, and the matting agent is DA-60, wax or fumed silica.

6. The anti-permeation aluminum-based nanoceramic coating according to claim 1, characterized in that: The auxiliary agent includes a leveling agent, a dispersant or a pH adjuster.

7. A method for preparing the anti-permeation aluminum-based nanoceramic coating according to any one of claims 1 to 6, characterized in that, The method comprises the following steps: S1: dispersing the modified Al2O3 nanofiber and the nanoceramic powder into an organic solvent, and then adding a dispersant and performing ultrasonic treatment; S2: adding the solvent type acrylic resin and the nanometer titanium dioxide hybrid material into an aqueous solution containing the matting agent and the initiator, and using a homogenizer to form a stable emulsion; S3: adding the stable emulsion obtained in step S2 into the mixed solution obtained in step S1, adding the perfluoropolyether and the silicone monomer, and fully stirring to react until microcapsules are formed in the solution, and then using a pH adjuster to adjust the pH of the system to neutral. S4, the solution is added into the paint sprayer, and the microcapsules are shaped once under the action of high pressure to form the microcapsule paint with droplet shape.

8. The use of the anti-permeation aluminum-based nanoceramic coating as claimed in any one of claims 1 to 6 for repairing and reinforcing the surface of brick and stone masonry of historical buildings.

Images