CN-120924143-B - Self-repairing protective coating material, self-repairing protective coating, preparation method of self-repairing protective coating and damaged coating repairing method

Abstract

The application provides a self-repairing protective coating material, a self-repairing protective coating, a preparation method thereof and a damaged coating repairing method, and relates to the technical field of coatings. The raw materials of the self-repairing protective coating material comprise diisocyanate, double-active functional group end-capped polysiloxane and 2, 5-diamino-1, 3, 4-thiadiazole. The preparation method comprises the steps of adding diisocyanate into double-active functional group end-capped polysiloxane, heating for reaction under the action of a catalyst, adding 2, 5-diamino-1, 3, 4-thiadiazole, and heating for post-treatment. The self-repairing protective coating material has the advantages that the polysiloxane long chain segment with high chemical stability provides good ageing resistance for the coating, the thiadiazole structure, the carbamate group or the urea group structure and the base material form various interaction forces to cooperatively enhance the adhesive force, the carbamate group or the urea group hydrogen bond provides excellent self-repairing performance, and the healing and repairing of the scratch area of the coating can be realized after the short-term heating.

Inventors

• MA LINGWEI
• WANG JINKE
• ZHANG DAWEI
• CHEN ZHIBIN
• ZHANG BOWEI

Assignees

• 北京科技大学

Dates

Publication Date

20260508

Application Date

20250815

Claims (4)

1. 1. A material for a self-repairing protective coating is characterized by comprising diisocyanate, double-active functional group end-capped polysiloxane and 2, 5-diamino-1, 3, 4-thiadiazole; the diisocyanate is a mixture of isophorone diisocyanate and other types of diisocyanate, wherein the ratio of the isophorone diisocyanate to the total molar amount of the diisocyanate is not less than 60 percent, and the other types of diisocyanate comprise one or more of aliphatic diisocyanate and aromatic diisocyanate; The double-active functional group end-capped polysiloxane is a mixture of aminopropyl end-capped polydimethylsiloxane and hydroxyl end-capped polydimethylsiloxane, and the ratio of the aminopropyl end-capped polydimethylsiloxane to the total molar weight of the double-active functional group end-capped polysiloxane is not less than 50%; The molar ratio of the amount of the diisocyanate to the sum of the amounts of the dual active functional group-terminated polysiloxane and the 2, 5-diamino-1, 3, 4-thiadiazole is 1.15:1-1:1, and the molar ratio of the dual active functional group-terminated polysiloxane to the 2, 5-diamino-1, 3, 4-thiadiazole is 19:1-15:5; The average molecular weight of the double-active functional group end-capped polysiloxane is 1000g/mol-6000g/mol; the preparation method of the material for the self-repairing protective coating comprises the following steps: Adding diisocyanate into double-active functional group end-capped polysiloxane under the protection atmosphere, heating under the action of a catalyst to perform a first reaction, then adding 2, 5-diamino-1, 3, 4-thiadiazole, heating to perform a second reaction, and performing post-treatment to obtain the material for the self-repairing protective coating; The diisocyanate and the double-active functional group end-capped polysiloxane are dissolved in advance by using a first organic solvent to obtain a corresponding solution, wherein the first organic solvent comprises one or more of chloroform, toluene and tetrahydrofuran; The 2, 5-diamino-1, 3, 4-thiadiazole is dissolved by N, N-dimethylformamide in advance to obtain a corresponding solution; The temperature of the first reaction is 50-70 ℃ and the time is 1-4h; The temperature of the second reaction is 60-80 ℃ and the time is 12-36h; the catalyst comprises one or more of dibutyl tin dilaurate, triethylene diamine and bismuth neodecanoate; the post-treatment comprises rotary evaporation, water precipitation and drying which are sequentially carried out.
2. 2. A self-healing protective coating, characterized in that its raw materials comprise the material for self-healing protective coating according to claim 1.
3. 3. The self-healing protective coating according to claim 2, wherein the thickness of the self-healing protective coating is 50-300 μm.
4. 4. A method of preparing the self-healing protective coating of claim 2 or 3, comprising: dissolving the material for the self-repairing protective coating by using a second organic solvent, and then setting the material on the surface of a substrate, and curing for 1-24 hours at 40-80 ℃; The second organic solvent comprises one or more of butyl acetate, chloroform and tetrahydrofuran.

Description

Self-repairing protective coating material, self-repairing protective coating, preparation method of self-repairing protective coating and damaged coating repairing method Technical Field The application relates to the technical field of coatings, in particular to a self-repairing protective coating material, a self-repairing protective coating, a preparation method of the self-repairing protective coating and a damaged coating repairing method. Background Organic corrosion-resistant coatings become an important means of protecting metals from corrosion due to their physical barrier effect. Although organic coatings protect metals from corrosion over time, their protective properties tend to be difficult to maintain under mechanical damage and long-term aging degradation. Specifically, mechanical damage can directly damage the integrity of the coating, aging caused by ultraviolet rays, water and other environmental factors can lead to the decomposition of a resin chain segment of the coating to cause pulverization, embrittlement and other phenomena, and penetration and diffusion of corrosive media can accumulate corrosion products at a coating/metal interface and lead to the stripping of the coating so as to accelerate the failure of the coating. In view of the complexity of the failure factor of the coating, the ageing resistance of the coating is improved, the self-repairing function is developed, and the anti-corrosion coating is two key strategies for prolonging the service life of the anti-corrosion coating. Organosilicon materials are considered desirable anti-aging materials because of the high bond energy si—o bonds in their backbone (providing excellent photo-aging resistance) and low surface energy (helping to mitigate hydrolytic aging). However, its low surface energy also results in poor adhesion to the substrate, commercial Polydimethylsiloxanes (PDMS) are typically less than 1 MPa, silicone polyureas or silicone polyurethanes are typically less than 2MPa, and are prone to release from the substrate under external forces, thereby losing barrier protection. At the same time, these silicone materials generally lack self-healing capabilities and, once broken, the corrosive medium rapidly invades and exacerbates the corrosion reaction. Therefore, there is a need to develop organic anti-corrosion coatings that combine strong adhesion, excellent aging resistance and self-healing capabilities to synergistically increase their service life. Disclosure of Invention The application aims to provide a self-repairing protective coating material, a self-repairing protective coating, a preparation method thereof and a damaged coating repairing method, so as to solve the problems. In order to achieve the above purpose, the application adopts the following technical scheme: A self-repairing protective coating material comprises diisocyanate, double-active functional group end-capped polysiloxane and 2, 5-diamino-1, 3, 4-thiadiazole; The diisocyanate comprises isophorone diisocyanate and/or other types of diisocyanate, and the other types of diisocyanate comprise one or more of aliphatic diisocyanate, alicyclic diisocyanate and aromatic diisocyanate; the dual active functional group end-capped polysiloxane comprises aminopropyl end-capped polydimethylsiloxane and/or hydroxyl end-capped polydimethylsiloxane; the molar ratio of the amount of the diisocyanate to the sum of the amounts of the dual active functional group-terminated polysiloxane and the 2, 5-diamino-1, 3, 4-thiadiazole is 1.15:1-1:1, and the molar ratio of the dual active functional group-terminated polysiloxane to the 2, 5-diamino-1, 3, 4-thiadiazole is 19:1-15:5. Alternatively, the molar ratio of the amount of diisocyanate to the sum of the amounts of the dual active functional group-blocked polysiloxane and the 2, 5-diamino-1, 3, 4-thiadiazole may be any value between 1.15:1, 1.1:1, 1:1, or 1.15:1-1:1, and the molar ratio of the dual active functional group-blocked polysiloxane and the 2, 5-diamino-1, 3, 4-thiadiazole may be any value between 19:1, 18:2, 17:3, 16:4, 15:5, or 19:1-15:5. Preferably, the self-healing protective coating material meets at least one of the following conditions: (1) The diisocyanate is a mixture of isophorone diisocyanate and other types of diisocyanate, and the proportion of isophorone diisocyanate in the total molar amount of the diisocyanate is not less than 60%; Alternatively, the ratio of isophorone diisocyanate to the total molar amount of the diisocyanate may be any value of 60%, 70%, 80%, 90%, 95% or not less than 60%; (2) The double-active functional group end-capped polysiloxane is a mixture of aminopropyl end-capped polydimethylsiloxane and hydroxyl end-capped polydimethylsiloxane, and the ratio of the aminopropyl end-capped polydimethylsiloxane to the total molar weight of the double-active functional group end-capped polysiloxane is not less than 50%; alternatively, the ratio of the aminopropyl terminated po