Self-repairing coating and preparation method thereof

Abstract

The invention discloses a self-repairing coating and a preparation method thereof. The preparation method comprises the following steps: S1, selecting polylactic acid as a substrate material; s2, dissolving and blending a polylactic acid solution: dissolving polylactic acid powder in a solvent; s3, adding a functional reinforcing material into the polylactic acid solution; s4, performing a fluorinated surface treatment agent and silanization modification technology on the product in S3, and then adopting an ultrasonic-assisted dispersion technology to ensure that the functional nanoparticles are uniformly distributed in the solution; and S5, adding a novel cross-linking agent which accounts for 5% of the total volume and is used for promoting the cross-linking reaction between polylactic acid chains. And S6, adopting a dual drying process, and combining freeze drying and supercritical carbon dioxide drying technologies. The coating provided by the invention has an efficient self-repairing function, excellent environmental adaptability and relatively low cost. The coating can be rapidly repaired after being damaged, original protection performance is recovered, external intervention is not needed in the repairing process, and the repairing effect is lasting and stable.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer coatings, and in particular to a self-repairing coating and a preparation method thereof. Background Art

[0002] With the increasing demands for material performance in modern industry and daily life, coating materials are playing an increasingly important role in various fields, particularly in providing protection, decoration, and enhanced functionality on substrates such as metal, concrete, and plastic. Coatings not only enhance a material's corrosion resistance, wear resistance, and oxidation resistance, but also improve its aesthetics. However, over time, coating materials are inevitably affected by the external environment and physical or chemical effects, leading to coating shedding, scratches, cracks, and other problems. This results in a loss of protective properties on the material surface, increasing maintenance costs and impacting long-term performance. Therefore, the development of self-healing coating materials has become a key research direction in materials science today. Self-healing coatings can not only automatically repair themselves when damaged, restoring their original properties, but also effectively extend the material's service life and reduce maintenance costs.

[0003] At present, although traditional coating materials such as metal coatings and polymer coatings can provide certain protection, they are often affected by the external environment or physical and chemical effects during use, resulting in damage to the coating. For example, the coating is prone to cracking, peeling, etc. when subjected to external impact, friction, chemical erosion, etc. When the coating is damaged, the substrate is exposed to the external environment, leading to problems such as corrosion and oxidation. Existing repair methods usually rely on manual intervention, such as manual application, spraying or heating. Although these methods can temporarily restore the protective effect of the coating, the repair effect is usually not as good as the original coating, and the repair process is cumbersome and costly. Especially when the damage to the coating is large or deep, traditional repair methods are often powerless and it is difficult to restore the original performance of the coating. Therefore, how to improve the durability and self-repair ability of the coating and reduce manual intervention has become an important research direction in coating technology.

[0004] Self-healing coating technology has garnered widespread attention in recent years and has become a cutting-edge field in materials science. Self-healing coatings are coatings that, upon external damage, can automatically identify and repair damaged areas, restoring their original functionality. Advances in self-healing coating research offer new solutions to address the limitations of traditional coatings. Existing self-healing coating technologies primarily include microcapsule repair technology, reversible chemical repair technology, and self-healing polymer repair technology. Microcapsule repair technology incorporates microcapsules into the coating. When damaged, the microcapsules rupture, releasing the encapsulated repair agent to fill the damaged area. Reversible chemical repair technology introduces molecules with reversible chemical reactions, enabling the coating to self-repair upon damage. Self-healing polymer technology involves designing polymers with self-healing properties, enabling them to recover to their original shape through chemical reactions or deformation after external damage. While these technologies address the issue of coating damage repair to some extent, they still have drawbacks, primarily manifested in unstable repair results, slow repair speeds, prone to leakage of the repair material, and poor environmental adaptability. Existing self-healing coatings often fail to achieve ideal repair results, particularly in complex environments such as high and low temperatures, high humidity, or chemical corrosion.

[0005] Therefore, how to design a self-healing coating that is efficient, stable and suitable for a variety of environmental conditions has become a key issue in current research. Summary of the Invention

[0006] The present invention aims to provide a self-healing coating and its preparation method, which exhibits efficient self-repair capabilities, excellent environmental adaptability, and low cost. The coating can rapidly repair itself after damage, restoring its original protective properties. This repair process requires no external intervention, and the effect is long-lasting and stable.

[0007] The above technical objectives of the present invention are achieved through the following technical solutions: A method for preparing a self-repairing coating comprises the following steps: S1, selecting polylactic acid as the base material; S2. Dissolving and preparing polylactic acid solution: dissolving polylactic acid powder in a solvent; S3, adding functional reinforcing materials to the polylactic acid solution; S4, subjecting the product in S3 to a fluorinated surface treatment agent and silanization modification technology, and then using ultrasonic-assisted dispersion technology to ensure that the functional nanoparticles are evenly distributed in the solution; S5. Adding a new cross-linking agent in an amount of 5% of the total volume to promote the cross-linking reaction between the polylactic acid chains; S6 adopts a double drying process, combining freeze drying and supercritical carbon dioxide drying technology.

[0008] Further preferably, in S2, 1.5 g of polylactic acid powder is dissolved in a solvent, and the solvent includes dichloromethane or chloroform.

[0009] Further preferably, in S2, the solution is stirred in a temperature range of 60°C to 70°C in combination with magnetic stirring and heating until it becomes completely transparent, and the concentration of the solution is precisely controlled to be 1.5 to 3.0 g / ml.

[0010] Further preferably, in S3, the functionalized reinforcing material includes 1 g of silicon dioxide nanoparticles and 5 ml of graphene oxide.

[0011] Further preferably, in S5, the new cross-linking agent includes 1,6-diisocyanate and triaminopropyltriethoxysilane, the temperature of the cross-linking reaction is set between 50°C and 70°C, and the amount of cross-linking agent added and the reaction rate are precisely controlled by spin coating and electrospinning technology to ensure the uniformity and optimal effect of cross-linking.

[0012] Further preferably, in S6, the prepared aerogel coating sample is placed in a freeze drying device and freeze-dried at a low temperature of -40°C to -80°C, and water is removed by sublimation to maintain high porosity and low density. Then, supercritical CO2 drying technology is used to further remove residual solvent and water to ensure the ultra-low density and high thermal insulation performance of the aerogel.

[0013] A self-repairing coating is prepared according to the above-mentioned method for preparing a self-repairing coating.

[0014] In summary, the present invention has the following beneficial effects: First, the coating of the present invention exhibits efficient self-healing capabilities, excellent environmental adaptability, and low cost. After damage, the coating can rapidly repair itself, restoring its original protective properties. This repair process requires no external intervention, and the repair effect is long-lasting and stable. Through its innovative design, the coating of the present invention not only exhibits excellent durability and self-healing capabilities, but also utilizes environmentally friendly materials, meeting the requirements of green and sustainable development and possessing broad application prospects.

[0015] Secondly, the present invention combines supercritical drying technology with temperature control optimization to ensure that the aerogel has higher stability and strength while maintaining its high specific surface area and low density.

[0016] Third, the coating of the present invention is enhanced by innovative surface functionalization technology and nanomaterials to further improve the performance of aerogel, especially in terms of anti-pollution, anti-ultraviolet and thermal stability.

[0017] Fourthly, the aero-gel is enhanced in antibacterial performance, thermal stability and mechanical strength by introducing functional nanomaterials such as titanium dioxide nanoparticles and carbon nanotubes. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is an effect display diagram of the coating in the application; DETAILED DESCRIPTION The application will be further described in detail below in combination with the drawings.

[0019] Embodiment, a preparation method of a self-repairable coating, comprising the following steps: S1, selecting polylactic acid as a base material. Polylactic acid is a bio-based material with good biodegradability and environmental protection characteristics, suitable for the preparation of green coatings.

[0020] S2, dissolving and preparing a polylactic acid solution: 1.5g of polylactic acid powder is dissolved in a solvent, which includes dichloromethane or chloroform to ensure complete dissolution of polylactic acid. In order to obtain a uniform solution, a combination of magnetic stirring and heating is used to stir the solution to complete transparency at a temperature range of 60-70°C. The concentration of the solution is accurately controlled at 1.5-3.0g / ml to ensure that it is suitable for subsequent cross-linking reaction and aero-gel formation. The control of this process can ensure the uniformity of polylactic acid in the solution and provide a stable basis for the subsequent steps.

[0021] S3, functionalized reinforcing materials are added to the polylactic acid solution, including 1g of silica nanoparticles and 5ml of graphene oxide. This is to further improve the mechanical strength, thermal stability and protective function of the aero-gel.

[0022] S4, fluorinated surface treatment agent and silanization modification technology are used on the product in S3, and ultrasonic assisted dispersion technology is used to ensure uniform distribution of functional nanoparticles in the solution. This is to improve the water resistance, anti-pollution and adhesion to the substrate of the aero-gel.

[0023] S5, a new type of cross-linking agent is added, with a dosage of 5% of the total volume, to promote the cross-linking reaction between polylactic acid chains. The new cross-linking agent includes 1,6-diisocyanate and triaminopropyl triethoxysilane. The cross-linking reaction temperature is set between 50-70°C, and the amount of cross-linking agent added and the reaction rate are accurately controlled by spin coating and electrospinning technology to ensure uniformity and optimal effect of cross-linking. This is to further improve the mechanical strength and thermal stability of the aero-gel.

[0024] S6. A double drying process was adopted, combining freeze drying and supercritical carbon dioxide drying technology. The prepared aerogel coating sample was placed in a freeze drying device and freeze-dried at a low temperature of -40°C to -80°C. Sublimation was used to remove moisture, maintaining high porosity and low density. Then, supercritical CO2 drying technology was used to further remove residual solvent and moisture, ensuring the ultra-low density and high thermal insulation performance of the aerogel. It is used to obtain aerogels with ultra-high specific surface area and low density. Through this double drying technology, not only can the solvent be effectively removed, but also the microporous structure of the aerogel can be maintained to the greatest extent, thereby improving its overall performance.

[0025] Specifically, the present invention uses polylactic acid as a base material to prepare aerogel. Polylactic acid is an environmentally friendly material with good biodegradability. As a polymer material, it has high thermal stability and excellent mechanical properties. Through the preparation process designed by the present invention, polylactic acid can effectively form an aerogel structure at high temperatures, while maintaining low density and high specific surface area, providing excellent thermal insulation and compressive strength. This technology precisely controls the solubility of polylactic acid, the cross-linking reaction and the subsequent drying process, so that the final aerogel material has good stability and mechanical properties, which is particularly suitable for the development of high-performance thermal insulation and protective materials.

[0026] The present invention combines supercritical drying technology with temperature control optimization to ensure that the aerogel has higher stability and strength while maintaining its high specific surface area and low density. Traditional drying methods easily lead to incomplete removal of moisture in the aerogel, affecting its pore structure and performance. The present invention uses supercritical CO2 drying technology, which can completely remove the solvent without destroying the pore structure of the aerogel, thereby obtaining a more uniform and high-quality aerogel. Combined with temperature control optimization, the temperature and pressure changes during the drying process can be precisely controlled to avoid shrinkage or deformation of the aerogel during the drying process, ensuring that the final product has stable physical properties and excellent thermal insulation and mechanical properties. Innovative surface functionalization technology and nanomaterial enhancement are then used to further improve the performance of the aerogel, especially in terms of anti-pollution, anti-ultraviolet and thermal stability. In order to improve the water resistance, anti-pollution properties and adhesion to the substrate of the aerogel material, the present invention adopts fluorination surface treatment and silanization modification technology. These surface modification methods can effectively enhance the hydrophobicity of the aerogel surface, prevent moisture penetration and accumulation of pollutants, thereby maintaining its efficient thermal insulation function and significantly improving its service life in various environments.

[0027] In addition, the present application also enhances the antibacterial performance, thermal stability and mechanical strength of aerogels by introducing functional nanomaterials such as titanium dioxide nanoparticles, carbon nanotubes, etc. Titanium dioxide, as a material with strong antibacterial properties, can effectively improve the antimicrobial ability of aerogels, while carbon nanotubes can help improve the thermal conductivity and structural strength of aerogels. Through the addition of these reinforcing materials, aerogels not only have better physical properties, but also exhibit more excellent performance in harsh environments, suitable for use in building, energy, environmental protection and other fields.

[0028] In summary, the defects of traditional aerogel materials in environmental protection and high strength are solved, and through innovative surface modification and nanomaterial enhancement, the multifunctionality and high efficiency of aerogels are realized. Through the technology of the present application, the application prospect of aerogel materials has been greatly expanded, especially in high-temperature insulation, anti-pollution protection and long-term use, etc., with significant advantages.

[0029] It should be noted that, as Figure 1 shown, the self-healing performance of the coating is demonstrated. First, the intact aerogel coating is cut in half with scissors. After cutting, the coating is contacted at room temperature, and after 15 minutes of contact, the cut aerogel coating recombines together, indicating the excellent self-healing performance of the coating.

[0030] This specific embodiment is only an explanation of the present application, and is not a limitation of the present application. Those skilled in the art can make modifications to this embodiment without creative contribution after reading this specification, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A method for preparing a self-repairing coating, characterized in that: The following steps are involved: S1, selecting polylactic acid as the base material; S2. Dissolving and preparing polylactic acid solution: dissolving polylactic acid powder in a solvent; S3, adding functional reinforcing materials to the polylactic acid solution; S4, subjecting the product in S3 to a fluorinated surface treatment agent and silanization modification technology, and then using ultrasonic-assisted dispersion technology to ensure that the functional nanoparticles are evenly distributed in the solution; S5. Adding a new cross-linking agent in an amount of 5% of the total volume to promote the cross-linking reaction between the polylactic acid chains; S6 adopts a double drying process, combining freeze drying and supercritical carbon dioxide drying technology.

2. The method for preparing a self-repairing coating according to claim 1, characterized in that: In S2, 1.5 g of polylactic acid powder is dissolved in a solvent, and the solvent includes dichloromethane or chloroform.

3. The method for preparing a self-repairing coating according to claim 2, characterized in that: In the S2, the solution is stirred in a temperature range of 60°C to 70°C by combining magnetic stirring with heating until it becomes completely transparent, and the concentration of the solution is precisely controlled within a range of 1.5 to 3.0 g / ml.

4. The method for preparing a self-repairing coating according to claim 3, characterized in that: In S3, the functionalized reinforcing material includes 1 g of silicon dioxide nanoparticles and 5 ml of graphene oxide.

5. The method for preparing a self-repairing coating according to claim 4, characterized in that: In the S5, the new cross-linking agent includes 1,6-diisocyanate and triaminopropyltriethoxysilane, the temperature of the cross-linking reaction is set between 50°C and 70°C, and the addition amount and reaction rate of the cross-linking agent are precisely controlled by spin coating and electrospinning technology to ensure the uniformity and optimal effect of cross-linking.

6. The method for preparing a self-repairing coating according to claim 5, characterized in that: In the S6, the prepared aerogel coating sample is placed in a freeze-drying device and freeze-dried at a low temperature of -40°C to -80°C. Water is removed by sublimation to maintain high porosity and low density. Then, supercritical CO2 drying technology is used to further remove residual solvent and moisture to ensure the ultra-low density and high thermal insulation performance of the aerogel.

7. A self-repairing coating, characterized in that: The self-repairing coating is prepared according to the method for preparing the self-repairing coating according to any one of claims 1 to 6.

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