Coating and preparation method thereof

Abstract

The invention provides a coating and a preparation method thereof. The coating comprises a resin matrix, a photo-thermal material, a dynamic polymer and an elastic soft segment polymer. The coating can be used for repairing microcosmic to macroscopic multi-scale defects, has a good repairing effect, and can be used for realizing repeated self-repairing for multiple times only under the action of sunlight.

Description

Technical Field

[0001] The present invention relates to the field of intelligent self-repairing coatings, and in particular to a coating that can utilize sunlight to repair microscopic and macroscopic defects on the surface of the coating multiple times, and a preparation method thereof. Background Art

[0002] Organic coatings are widely used in marine engineering equipment. However, microscopic defects such as pores and cracks are easily formed in the coating during the coating and service process. Corrosive media such as water, oxygen, and salt in the high temperature, high humidity, and high salt marine atmospheric environment reach the substrate surface through the defects, causing corrosion of the substrate metal under the coating. The corrosion of the substrate will accelerate the failure of the coating, thereby increasing the repair and maintenance costs of engineering equipment and posing safety hazards to the equipment.

[0003] Self-repair provides a new idea for improving the performance of organic coatings. Self-repairing coating technology can be divided into two types: external aid type and intrinsic type. External aid self-repairing coatings mainly use certain technical means such as microcapsules and other micro-nano containers to encapsulate the repair agent and add it to the coating. When the coating is damaged, the repair substance can diffuse to the damaged area under the action of concentration difference and repair it. External aid self-repairing coating repair can realize the self-repair of the coating when microcracks occur, thereby avoiding the continued expansion of microcracks caused by the infiltration of corrosive media. However, the main disadvantage of external aid self-repairing coatings is that they cannot achieve multiple repairs of the same defect. At the same time, damage to micro-nano containers during the coating preparation process also limits its application. Intrinsic self-repairing completes the self-repair of damage through the material's own reversible chemical reaction. Its multiple reversible repair characteristics have attracted widespread attention from researchers. However, the main defect of the current intrinsic self-repairing technology is that its repair process often requires manual heating, and it cannot achieve autonomous repair; and the defects produced by the coating under actual working conditions may involve multiple scales, such as microscopic and macroscopic, while intrinsic self-repairing can only repair microscopic defects. Therefore, how to achieve the material's repair of multi-scale defects is also one of the main problems of the current intrinsic self-repairing technology. In addition, patent CN113861800 provides a solar-driven self-repairing coating, but the self-repairing coating uses small molecules for repair, and its protective performance after repair is poor, and it can only repair defects such as scratches or microscopic holes on the coating surface. Summary of the invention

[0004] The first aspect of the present invention aims to provide a coating.

[0005] The second aspect of the present invention aims to provide a method for preparing a coating.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] The first aspect of the present invention provides a coating, which includes a resin matrix, a photothermal material, a dynamic polymer and an elastic soft segment polymer, wherein the elasticity index of the elastic soft segment polymer is an elongation at break ≥ 200%.

[0008] In some embodiments of the present invention, the elastic index of the elastic soft segment polymer is an elongation at break of 200%, 300%, 400%, 500%, 600% or 700%.

[0009] In some embodiments of the present invention, the elastic soft segment polymer is one or more of extended chain flexible epoxy resin polyethylene glycol diglycidyl ether (LPEGDGE), extended chain flexible epoxy resin polypropylene glycol diglycidyl ether (LPPGDGE), extended chain flexible epoxy resin poly(dimethylsiloxane) diglycidyl ether (LPDSDGE), extended chain flexible epoxy resin 1,2-cyclohexanediol diglycidyl ether (LCHDDGE) and extended chain flexible epoxy resin 1,6-hexanediol diglycidyl ether (LHDDGE).

[0010] In some specific embodiments of the present invention, the elastic soft segment polymer is chain-extended flexible epoxy resin polyethylene glycol diglycidyl ether (LPEGDGE).

[0011] In some specific embodiments of the present invention, the elastic soft segment polymer is chain-extended flexible epoxy resin polypropylene glycol diglycidyl ether (LPPGDGE).

[0012] In some specific embodiments of the present invention, the chain-extended flexible epoxy resin is poly(dimethylsiloxane) diglycidyl ether (LPDSDGE).

[0013] In some specific embodiments of the present invention, the elastic soft segment polymer is a chain-extended flexible epoxy resin 1,2-cyclohexanediol diglycidyl ether (LCHDDGE).

[0014] In some specific embodiments of the present invention, the elastic soft segment polymer is a chain-extended flexible epoxy resin 1,6-hexanediol diglycidyl ether (LHDDGE).

[0015] In some embodiments of the present invention, the synthesis of the elastic soft segment polymer can be obtained by chemical reaction of materials containing thiol groups such as polyethylene glycol diglycidyl ether or (PEGDGE), polypropylene glycol diglycidyl ether (PPGDGE), poly(dimethylsiloxane) diglycidyl ether (LPDSDGE), 1,2-cyclohexanediol diglycidyl ether (LCHDDGE), 1,6-hexanediol diglycidyl ether (LHDDGE) and ethylene glycol dimercaptoacetate (GDMA).

[0016] In some embodiments of the present invention, the dynamic polymer is an epoxy glass containing a carboxyl ester bond-disulfide bond or an epoxy glass containing a hydroxy ester bond-disulfide bond. In some specific embodiments of the present invention, the dynamic polymer is an epoxy glass containing a carboxyl ester bond-disulfide bond. In some specific embodiments of the present invention, the dynamic polymer is an epoxy glass containing a hydroxy ester bond-disulfide bond.

[0017] In some embodiments of the present invention, the topological freezing transition temperature of the dynamic polymer is ≤ 60° C. In some embodiments of the present invention, it is characterized in that the topological freezing transition temperature of the dynamic polymer is 60° C., 50° C., 40° C. or 30° C.

[0018] In some embodiments of the present invention, the resin matrix includes one or more of epoxy resin, alkyd resin, acrylic resin, polyurethane and fluorocarbon resin. In some specific embodiments of the present invention, the resin matrix is ​​epoxy resin. In some specific embodiments of the present invention, the resin matrix is ​​alkyd resin. In some specific embodiments of the present invention, the resin matrix is ​​acrylic resin. In some specific embodiments of the present invention, the resin matrix is ​​polyurethane resin. In some specific embodiments of the present invention, the resin matrix is ​​fluorocarbon resin.

[0019] In some embodiments of the present invention, the photothermal material is ferrosoferric oxide nanoparticles.

[0020] In some embodiments of the present invention, the average particle size of the ferrosoferric oxide nanoparticles is 10 to 20 nm. In some specific embodiments of the present invention, the average particle size of the ferrosoferric oxide nanoparticles is 10 nm. In some specific embodiments of the present invention, the average particle size of the ferrosoferric oxide nanoparticles is 15 nm. In some specific embodiments of the present invention, the average particle size of the ferrosoferric oxide nanoparticles is 20 nm.

[0021] In some embodiments of the present invention, the contents of the components of the coating are: base resin 15-40wt.%, elastic soft segment polymer 16-20wt.%, dynamic polymer 20-25wt.%, photothermal material 3-5wt.%, solvent content 20-35wt.%.

[0022] In some embodiments of the present invention, the content of the base resin is 15wt.%, 20wt.%, 25wt.%, 30wt.%, 35wt.% or 40wt.%.

[0023] In some embodiments of the present invention, the content of the elastic soft segment polymer matrix resin is 16 wt.%, 17 wt.%, 18 wt.%, 19 wt.% or 20 wt.%.

[0024] In some embodiments of the present invention, the content of the dynamic polymer is 20wt.%, 21wt.%, 22wt.%, 23wt.%, 24wt.% or 25wt.%.

[0025] In some embodiments of the present invention, the content of the photothermal material is 3wt.%, 4wt.% or 5wt.%.

[0026] In some embodiments of the present invention, the contents of the coatings and their components are as follows: 15 wt.% epoxy resin, 20 wt.% extended chain flexible epoxy resin polyethylene glycol diglycidyl ether, 25 wt.% epoxy glass containing carboxyl ester bonds-disulfide bonds, 5 wt.% ferrosoferric oxide nanoparticles, and 35 wt.% solvent content.

[0027] In some embodiments of the present invention, the contents of the coatings and their components are: 35 wt.% alkyd resin, 17 wt.% extended chain flexible epoxy resin polypropylene glycol diglycidyl ether, 22 wt.% epoxy glass containing hydroxy ester bonds and disulfide bonds, 3 wt.% ferrosoferric oxide nanoparticles, and 23 wt.% solvent content.

[0028] In some embodiments of the present invention, the contents of the coatings and their components are: 25 wt.% acrylic resin, 16 wt.% extended chain flexible epoxy resin poly(dimethylsiloxane) diglycidyl ether, 25 wt.% epoxy glass containing carboxyl ester bonds-disulfide bonds, 4 wt.% ferrosoferric oxide nanoparticles, and 30 wt.% solvent content.

[0029] In some embodiments of the present invention, the contents of the coatings and their components are: 40 wt.% of polyurethane, 17 wt.% of extended chain flexible epoxy resin 1,2-cyclohexanediol diglycidyl ether, 20 wt.% of epoxy glass containing hydroxy ester bonds and disulfide bonds, 3 wt.% of ferrosoferric oxide nanoparticles, and 20 wt.% of solvent content.

[0030] In some embodiments of the present invention, the contents of the coatings and their components are: 30 wt.% of fluorocarbon resin, 20 wt.% of extended chain flexible epoxy resin 1,6-hexanediol diglycidyl ether, 25 wt.% of epoxy glass containing carboxyl ester bonds and disulfide bonds, 3 wt.% of ferrosoferric oxide nanoparticles, and 22 wt.% of solvent content.

[0031] A second aspect of the present invention provides a method for preparing a coating, comprising the following steps:

[0032] (1) dispersing the base resin in a solvent;

[0033] (2) adding the elastic soft segment polymer and the dynamic polymer to the dispersed matrix resin in sequence;

[0034] (3) On the basis of step (2), photothermal particles are added to obtain a coating.

[0035] In some embodiments of the present invention, the method for preparing the coating comprises the following steps:

[0036] (1) Soft segment polymers and dynamic polymers are prepared by chemical synthesis.

[0037] (2) Add a certain amount of solvent and base resin into a container and stir thoroughly to make them evenly dispersed.

[0038] (3) Add a certain proportion of soft segment polymer and dynamic polymer to the above solution and stir to completely dissolve them.

[0039] (4) Finally, a certain proportion of photothermal material is added to the solution and stirred thoroughly to make it evenly dispersed to obtain a coating.

[0040] In some embodiments of the present invention, the preparation method is as follows: weigh 20-35wt.% of solvent and add it to a beaker, add 15-40wt.% of base resin to the solvent, stir it at a stirring speed of 400rpm / min on a high-speed disperser to make it evenly dispersed, then add 16-20wt.% of elastic soft segment polymer and 20-25wt.% of dynamic polymer in turn, stir it at a stirring speed of 800rpm / min on a high-speed disperser to make it fully dispersed, add 3-5wt.% of photothermal material, and disperse it at a stirring speed of 400rpm / min for 10 minutes to obtain a photothermal self-healing coating. When the coating is actually used, a curing agent needs to be added according to the properties of the resin or it can be used directly. The coating can be applied to various metal surfaces by brushing, spraying, rolling, spin coating, dipping, etc. according to actual needs, and a film can be formed after curing.

[0041] In some embodiments of the present invention, the solvent may be toluene, xylene or butanone, etc., according to the properties of the resin.

[0042] The present invention first prepares elastic soft segment polymers and dynamic polymers with controllable performance; then uses the polymerization induced phase separation method to construct a multi-phase integrated photothermal self-healing coating system, so that the soft segment polymer and the dynamic polymer in the system can be organically combined with the matrix resin: when the coating is intact, the soft segment polymer and the dynamic polymer can form a good multi-phase structure to shield the invasion of external corrosive media, and form a good molecular bond with the matrix to improve the binding force of the coating. When the coating is subjected to external force to produce microscopic or macroscopic defects, the coating is separated from the matrix resin, the elastic polymer can make the coating defects recover autonomously, and the dynamic polymer can make the coating section "autonomously fit" under the elasticity of the elastic soft segment polymer. At the same time, the dynamic polymer can undergo a reversible reaction under the heating of the photothermal material to completely repair the coating defects. Since the repair process only involves physical action and reversible chemical reaction, the repair process can be repeated multiple times, thereby realizing multiple repairs of microscopic or macroscopic defects. The present invention can effectively extend the protective life of the organic coating and provide a new solution for the preparation of high-performance self-healing coating systems in marine atmospheric environments.

[0043] When microscopic or macroscopic defects such as cracks occur, under sunlight, the dynamic polymers around the defects in the self-healing coating can be transformed into a viscous flow state, and driven by the elastic soft segment polymer, the defects can be "fitted" autonomously. After fitting, the dynamic polymers re-form a polymer network at the gap to completely repair the coating defects. Since the polymer network formed by the dynamic polymer acts as a physical shielding layer with good protective performance, it can block corrosive media such as water from reaching the surface of the metal substrate, so that the repaired defect area has good protective performance and extends the protective life. At the same time, the coating components that have been reasonably designed can ensure that the intact coating can still maintain good performance under long-term light.

[0044] The coating provided by the present invention can repair multi-scale defects from microscopic to macroscopic by means of the synergistic effect of the elastic soft segment polymer and the dynamic polymer, has a good repair effect, and can achieve repeated autonomous repairs only under the action of sunlight. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 A is the infrared spectrum of the dynamic polymer.

[0046] Figure 1 B is the dynamic polymer DSC curve.

[0047] Figure 1 C is the infrared thermal image of the coating without sunlight exposure.

[0048] Figure 1 D is the infrared thermal image of the coating exposed to sunlight for 5 minutes.

[0049] Figure 1E is the image before coating repair.

[0050] Figure 1 F is the image after coating restoration. Specific implementation (embodiment)

[0051] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0052] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the present application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or apparatuses.

[0053] In the present invention, "resin" generally refers to an organic polymer that has a softening or melting range after being heated, has a tendency to flow under the action of external force when softened, is solid, semi-solid, or sometimes liquid at room temperature. In a broad sense, any polymer compound that can be used as a raw material for processing plastic products is called a resin. The resin in the present invention is mainly epoxy resin, alkyd resin, acrylic resin, polyurethane, fluorocarbon resin, etc., which are used as the main material of the coating.

[0054] In the present invention, "chain-extended flexible epoxy resin" is an epoxy resin with high flexibility and ductility, which is mainly prepared by the thiol-epoxy click reaction between compounds containing epoxy groups at both ends such as polyethylene glycol diglycidyl ether and ethylene glycol dimercaptoacetate. Compared with rigid epoxy resin, chain-extended flexible epoxy resin has better impact resistance, fatigue resistance, low temperature resistance and adhesion. In the present invention, it mainly plays a role in the preliminary restoration of the defects generated.

[0055] In the present invention, "dynamic polymer" refers to a class of polymer systems formed by dynamic chemical bonds, which are reversible in chain breaking and formation under external conditions. In addition, the dynamic polymer structure is flexible and can be designed according to the requirements of material properties. The dynamic polymer used in the present invention is epoxy glass, which mainly plays the role of repairing coating defects under the action of light and heat.

[0056] In the present invention, "elongation at break" refers to the ratio of the maximum deformation of a material when subjected to a tensile force to its original length.

[0057] In the present invention, "topological freezing temperature" refers to the temperature at which a topological phase transition occurs in a material, at which the material is converted into a topological state. The topological freezing temperature is generally considered to be the critical temperature at which topological states appear in a material.

[0058] Example 1

[0059] (1) Preparation of chain-extended flexible epoxy resin polyethylene glycol diglycidyl ether (LPEGDGE): polyethylene glycol diglycidyl ether (PEGDGE) and ethylene glycol dimercaptoacetate (GDMA) were added into a reactor at a molar ratio of 2:1. After sufficient stirring, the reactor was heated to 50°C and a catalyst 2,4,6-tris(dimethylaminomethyl)phenol was added. The reaction was carried out for 1.5 hours under sufficient stirring. The reactants were poured into a polytetrafluoroethylene container for later use.

[0060] (2) Preparation of epoxy glass containing carboxyl ester bond-disulfide bond: Add bisphenol A diglycidyl ether (DGEBA) and 4,4′-dithiodibutyric acid (DTDA) in a polytetrafluoroethylene beaker at a molar ratio of 1:1. Heat the mixture to 100°C until the phases are miscible. Then add 10% mol of triazabicycloolefin in the monomer ratio, react for 30 minutes under sufficient stirring conditions, and then pour the mixture into a polytetrafluoroethylene mold for use.

[0061] (3) Preparation of coating: According to the total weight of the coating, 35 wt.% of toluene is weighed and added to a beaker, 15 wt.% of epoxy resin is added to the solvent, and the mixture is stirred at a speed of 400 rpm / min on a high-speed disperser to make it uniformly dispersed, and then 20 wt.% of chain-extended flexible epoxy resin polyethylene glycol diglycidyl ether and 25 wt.% of epoxy glass containing carboxyl ester bond-disulfide bond are added in sequence, and the mixture is stirred at a speed of 800 rpm / min on a high-speed disperser to make it fully dispersed, and then 5% of ferrosoferric oxide nanoparticles are added, and the mixture is dispersed at a stirring speed of 400 rpm / min for 10 minutes to obtain the coating. A certain proportion of curing agent needs to be added when the coating is actually used. The coating liquid can be applied to various metal surfaces by brushing, spraying, rolling, spin coating, dipping, etc. according to actual needs.

[0062] (4) Specific results are as follows Figure 1 As shown: Figure 1 The infrared spectrum results of A showed that the synthesized dynamic polymer contained dual dynamic bonds of carboxyl ester bonds and disulfide bonds; Figure 1 The DSC results of B showed that the glass transition temperature of the polymer was around 26°C; Figure 1 C is the infrared thermal image without sunlight exposure. Figure 1 D shows that after 5 minutes of exposure to midday sunlight, the surface temperature of the coating rises to about 50°C, prompting the surface defects to heal autonomously; Figure 1 E and Figure 1 The image comparison of F before and after coating repair shows that after a period of irradiation, the defects on the coating surface are repaired. The above self-repair results show that the coating involved in this patent can have a good self-repair effect on macroscopic large-scale defects under natural sunlight.

[0063] Example 2

[0064] (1) Preparation of chain-extended flexible epoxy resin polypropylene glycol diglycidyl ether (LPPGDGE): polypropylene glycol diglycidyl ether (PPGDGE) and ethylene glycol dimercaptoacetate (GDMA) were added into a reactor at a molar ratio of 2:1. After sufficient stirring, the reactor was heated to 55°C and a catalyst 2,4,6-tris(dimethylaminomethyl)phenol was added. The reaction was carried out for 1 hour under sufficient stirring. The reactants were poured into a polytetrafluoroethylene container for later use.

[0065] (2) Preparation of epoxy glass containing hydroxy ester bond-disulfide bond: Tung oil triglycidyl ester and 4-aminophenyl disulfide bond were added to a polytetrafluoroethylene beaker at a molar ratio of 1:1 of epoxy group:amino group. The mixture was heated to 110°C until phase miscibility occurred. After reacting for 30 minutes under sufficient stirring, the mixture was poured into a polytetrafluoroethylene mold for use.

[0066] (3) Preparation of coating: According to the total weight of the coating, 23 wt.% of xylene is weighed and added to a beaker, 35 wt.% of alkyd resin is added to the solvent, and the mixture is fully stirred at a stirring speed of 300 rpm / min on a high-speed disperser to make it uniformly dispersed, and then 17 wt.% of extended chain flexible epoxy resin polypropylene glycol diglycidyl ether and 22 wt.% of epoxy glass containing hydroxy ester bond-disulfide bond are added in sequence, and the mixture is fully dispersed at a stirring speed of 800 rpm / min on a high-speed disperser, and then 3% of ferrosoferric oxide nanoparticles are added, and the mixture is dispersed at a stirring speed of 400 rpm / min for 15 minutes to obtain the coating. The coating liquid can be applied on various metal surfaces by brushing, spraying, rolling, spin coating, dipping, etc. according to actual needs.

[0067] Example 3

[0068] (1) Preparation of chain-extended flexible epoxy resin poly(dimethylsiloxane) diglycidyl ether (LPDSDGE): poly(dimethylsiloxane) diglycidyl ether (PDSDGE) and ethylene glycol dithioacetate (GDMA) were added into a reactor at a molar ratio of 2:1. After sufficient stirring, the reactor was heated to 60°C and a catalyst 2,4,6-tris(dimethylaminomethyl)phenol was added. The reaction was carried out for 1.5 hours under sufficient stirring. The reactants were poured into a polytetrafluoroethylene container for later use.

[0069] (2) Preparation of epoxy glass containing carboxyl ester bond-disulfide bond: Add bisphenol A diglycidyl ether (DGEBA) and 4,4′-dithiodibutyric acid (DTDA) in a polytetrafluoroethylene beaker at a molar ratio of 1:1. Heat the mixture to 100°C until the phases are miscible. Then add 10% mol of triazabicycloolefin in the monomer ratio, react for 30 minutes under sufficient stirring conditions, and then pour the mixture into a polytetrafluoroethylene mold for use.

[0070] (3) Preparation of coating: According to the total weight of the coating, 30 wt.% of toluene is weighed and added to a beaker, 25 wt.% of acrylic resin is added to the solvent, and the mixture is stirred at a speed of 400 rpm / min on a high-speed disperser to make it uniformly dispersed, and then 16 wt.% of extended chain flexible epoxy resin poly(dimethylsiloxane) diglycidyl ether and 25 wt.% of carboxyl ester bond-disulfide bond epoxy glass are added in sequence, and the mixture is stirred at a speed of 800 rpm / min on a high-speed disperser to make it fully dispersed, and then 4% of ferrosoferric oxide nanoparticles are added, and the mixture is dispersed at a stirring speed of 500 rpm / min for 10 minutes to obtain a photothermal self-healing coating. The coating liquid can be applied to various metal surfaces by brushing, spraying, rolling, spin coating, dipping, etc. according to actual needs.

[0071] Example 4

[0072] (1) Preparation of chain-extended flexible epoxy resin 1,2-cyclohexanediol diglycidyl ether (LCHDDGE): 1,2-cyclohexanediol diglycidyl ether (CHDDGE) and ethylene glycol dimercaptoacetate (GDMA) were added into a reactor at a molar ratio of 2:1. After sufficient stirring, the reactor was heated to 55°C and a catalyst 2,4,6-tris(dimethylaminomethyl)phenol was added. The reaction was carried out under sufficient stirring for 1 hour. The reactants were poured into a polytetrafluoroethylene container for later use.

[0073] (2) Preparation of epoxy glass containing hydroxy ester bond-disulfide bond: Tung oil triglycidyl ester and 4-aminophenyl disulfide bond were added to a polytetrafluoroethylene beaker at a molar ratio of 1:1 of epoxy group:amino group. The mixture was heated to 110°C until phase miscibility occurred. After reacting for 30 minutes under sufficient stirring, the mixture was poured into a polytetrafluoroethylene mold for use.

[0074] (3) Preparation of coating: According to the total weight of the coating, 20wt.% of butanone is weighed and added to a beaker, 40wt.% of polyurethane is added to the solvent, and the mixture is stirred at 400rpm / min on a high-speed disperser to make it uniformly dispersed, and then 17wt.% of extended chain flexible epoxy resin 1,2-cyclohexanediol diglycidyl ether and 20wt.% of epoxy glass containing hydroxy ester bond-disulfide bond are added in sequence, and the mixture is stirred at 800rpm / min on a high-speed disperser to make it fully dispersed, and then 3% of ferrosoferric oxide nanoparticles are added, and the mixture is dispersed at 400rpm / min for 10 minutes to obtain a photothermal self-healing coating. The coating liquid can be applied to various metal surfaces by brushing, spraying, rolling, spin coating, dipping, etc. according to actual needs.

[0075] Example 5

[0076] (1) Preparation of chain-extended flexible epoxy resin 1,6-hexanediol diglycidyl ether (LHDDGE): 1,6-hexanediol diglycidyl ether (HDDGE) and ethylene glycol dimercaptoacetate (GDMA) were added into a reactor at a molar ratio of 2:1. After sufficient stirring, the reactor was heated to 60°C and a catalyst 2,4,6-tris(dimethylaminomethyl)phenol was added. The mixture was reacted for 1.5 h under sufficient stirring. The reactants were poured into a polytetrafluoroethylene container for later use.

[0077] (2) Preparation of epoxy glass containing carboxyl ester bond-disulfide bond: Add bisphenol A diglycidyl ether (DGEBA) and 4,4′-dithiodibutyric acid (DTDA) in a polytetrafluoroethylene beaker in a ratio of 1:1. Heat the mixture to 100°C until the phases are miscible. Then add 10% mol of triazabicycloolefin in the monomer ratio, react for 30 minutes under sufficient stirring, and pour the mixture into a polytetrafluoroethylene mold for use.

[0078] (3) Preparation of coating: According to the total weight of the coating, 22wt.% of xylene is weighed and added to a beaker, 30wt.% of fluorocarbon resin is added to the solvent, and the mixture is stirred at a speed of 400rpm / min on a high-speed disperser to make it uniformly dispersed. Then, 20wt.% of extended chain flexible epoxy resin 1,6-hexanediol diglycidyl ether and 25wt.% of carboxyl ester bond-disulfide bond epoxy glass are added in sequence, and the mixture is stirred at a speed of 600rpm / min on a high-speed disperser to make it fully dispersed. Then, 3% of ferrosoferric oxide nanoparticles are added and dispersed at a stirring speed of 400rpm / min for 10 minutes to obtain a photothermal self-healing coating. When the coating is actually used, a curing agent is added as needed. The coating liquid can be applied to various metal surfaces by brushing, spraying, rolling, spin coating, dipping, etc. according to actual needs, and a photothermal self-healing coating can be formed after curing.

Claims

1. A coating, characterized in that: The coating comprises a resin matrix, a photothermal material, a dynamic polymer and an elastic soft segment polymer.

2. The coating according to claim 1, characterized in that The elastic soft segment polymer is one or more of extended chain flexible epoxy resin polyethylene glycol diglycidyl ether (LPEGDGE), extended chain flexible epoxy resin polypropylene glycol diglycidyl ether (LPPGDGE), extended chain flexible epoxy resin poly(dimethylsiloxane) diglycidyl ether (LPDSDGE), extended chain flexible epoxy resin 1,2-cyclohexanediol diglycidyl ether (LCHDDGE) and extended chain flexible epoxy resin 1,6-hexanediol diglycidyl ether (LHDDGE).

3. The coating according to claim 1, characterized in that The dynamic polymer is an epoxy glass containing a carboxyl ester bond-disulfide bond or an epoxy glass containing a hydroxy ester bond-disulfide bond.

4. The coating according to claim 3, characterized in that The topological freezing transition temperature of the dynamic polymer is ≤60°C.

5. The coating according to claim 1, characterized in that The resin matrix includes one or more of epoxy resin, alkyd resin, acrylic resin, polyurethane and fluorocarbon resin.

6. The coating according to claim 1, characterized in that The photothermal material is ferroferric oxide nanoparticles.

7. The coating according to claim 1, characterized in that The contents of the coating components are as follows: 15-40wt.% of base resin, 16-20wt.% of elastic soft segment polymer, 20-25wt.% of dynamic polymer, and 3-5wt.% of photothermal material.

8. A method for preparing a coating, characterized in that: The steps include: (1) dispersing the base resin in a solvent; (2) adding the elastic soft segment polymer and the dynamic polymer to the dispersed matrix resin in sequence; (3) On the basis of step (2), photothermal particles are added to obtain a coating.

Images