Anticorrosive paint, preparation method thereof, anticorrosive coating and application

Abstract

The invention provides an anticorrosive paint, a preparation method thereof, an anticorrosive coating and application. The provided anticorrosive paint comprises a polymer matrix containing reversible chemical bonds and microcapsules dispersed in the polymer matrix. The microcapsule comprises a core material and a capsule wall coating the core material, and the core material comprises a fluorescent dye; the reversible chemical bond in the polymer matrix is one or more of Diels-Alder bond, disulfide bond and hydrogen bond. The anti-corrosion coating prepared from the anti-corrosion paint can realize damage early warning and repair tracking.

Description

Technical Field

[0001] The present invention belongs to the technical field of intelligent material synthesis, and specifically relates to an anti-corrosion paint and a preparation method thereof, an anti-corrosion coating and applications. Background Art

[0002] Coatings are widely used in the field of corrosion protection of metal materials due to their excellent shielding properties, strong adhesion and ease of use. However, traditional anti-corrosion coatings will inevitably produce microscopic defects (cracks, scratches, etc.) during service. If they are not repaired in time, the corrosion process will be aggravated. In severe cases, the coating may peel off and fail, thereby losing its protective effect on the metal substrate.

[0003] The current self-healing anti-corrosion coating only inhibits the invasion of corrosive media during the repair process, but does not specifically repair coating damage. It does not achieve true self-repair and cannot provide sensitive early warning. Summary of the invention

[0004] In view of the problems that the existing anti-corrosion coating cannot provide sensitive warning and cannot repair coating damage, an anti-corrosion coating and its preparation method, an anti-corrosion coating and application are provided.

[0005] In some embodiments, an anticorrosive coating is provided, comprising a polymer matrix containing reversible chemical bonds and microcapsules dispersed in the polymer matrix;

[0006] The microcapsule comprises a core material and a capsule wall covering the core material, wherein the core material comprises a fluorescent dye;

[0007] The reversible chemical bonds in the polymer matrix are one or more of Diels-Alder bonds, disulfide bonds and hydrogen bonds.

[0008] In some embodiments, the anti-corrosion coating satisfies one or more of the following characteristics:

[0009] (1) The raw materials for preparing the capsule wall include polymer prepolymers, organic solvents containing ester groups and benzene rings, urea, ammonium chloride, phenolic organic matter, maleic anhydride copolymers and formaldehyde; the polymer prepolymers include one or more of polyurethane prepolymers, polyurea-formaldehyde prepolymers, polyurethane / urea-formaldehyde prepolymers and polymethyl methacrylate prepolymers. Optionally, the polymer prepolymer in the raw materials for preparing the capsule wall is a polyurethane prepolymer;

[0010] (2) The fluorescent dye is one or more of 2',7'-dichlorofluorescein, 2',7'-difluorofluorescein, crystal violet lactone, and fluorescein isothiocyanate;

[0011] (3) The particle size of the microcapsule is 10 μm to 50 μm.

[0012] In some embodiments, the raw materials for preparing the polymer matrix include a polymer precursor, a curing agent, and an accelerator.

[0013] In some embodiments, the raw materials for preparing the polymer matrix meet one or more of the following characteristics:

[0014] (1) The polymer precursor in the raw material for preparing the polymer matrix is ​​one or more of polyurethane prepolymer, furfuryl glycidyl amine, epoxy resin prepolymer and phenolic resin prepolymer;

[0015] (2) The curing agent in the raw material for preparing the polymer matrix is ​​one or more of an amine curing agent containing an amino group, an adhesive containing an isocyanate group, and a curing agent containing an ester group; optionally, the amine curing agent is selected from one or more of polyetheramine, polyamide, aliphatic amine, and aromatic amine; optionally, the adhesive containing an isocyanate group is selected from one or more of toluene diisocyanate, isophorone diisocyanate, and dimethyltriphenylmethane tetraisocyanate; optionally, the curing agent containing an ester group is selected from one or more of vinyl acetate, propylene carbonate, and methyl methacrylate;

[0016] (3) The accelerator in the raw material for preparing the polymer matrix is ​​one or more of furan, maleimide, and organic matter containing a thiol group;

[0017] (4) In terms of feed amount, the mass ratio of the polymer precursor to the curing agent in the raw materials for preparing the polymer matrix is ​​(5-20): (1-5);

[0018] (5) Calculated by feed amount, the mass ratio of the polymer precursor to the promoter in the raw materials for preparing the polymer matrix is ​​(5-20): (1-25).

[0019] In some embodiments, the anti-corrosion coating satisfies one or more of the following characteristics:

[0020] (1) Calculated by feed amount, the weight ratio of the microcapsule to the polymer matrix is ​​(0.1-10):100;

[0021] (2) Calculated by feed amount, the mass ratio of urea, ammonium chloride and phenolic organic matter in the raw materials for preparing the capsule wall is (9-12): (0.9-3): (0.9-2);

[0022] (3) In the raw materials for preparing the microcapsules, the mass ratio of the polymer prepolymer in the core material and the capsule wall to the organic solvent containing an ester group and a benzene ring is (3-6): (80-100): (200:300) based on the feed amount.

[0023] In some embodiments, the anti-corrosion coating satisfies one or more of the following characteristics:

[0024] (1) Calculated by feed amount, the weight ratio of the microcapsules to the polymer matrix is ​​(0.5-5):100;

[0025] (2) Calculated by feed amount, the mass ratio of urea, ammonium chloride and phenolic organic matter in the raw materials for preparing the capsule wall is (9-12): (1-3): (1-2);

[0026] (3) In the raw materials for preparing the microcapsules, the mass ratio of the polymer prepolymer in the core material and the capsule wall to the organic solvent containing an ester group and a benzene ring is (3-4): (90-100): (200:300) based on the feed amount.

[0027] In some embodiments, the polymer matrix is ​​one or more of an epoxy polymer matrix containing Diels-Alder bonds and a polyurethane matrix containing Diels-Alder bonds.

[0028] In some embodiments, a method for preparing an anticorrosive coating is provided, comprising mixing microcapsules and a polymer matrix to prepare the anticorrosive coating; wherein:

[0029] The preparation method of the microcapsules comprises the following steps:

[0030] The core material, the polymer prepolymer and the organic solvent containing an ester group and a benzene ring are mixed to prepare a solution A.

[0031] Mixing urea, ammonium chloride, phenolic organic matter and maleic anhydride copolymer solution, adjusting the pH to 3.2-3.8, to prepare solution B;

[0032] Under a first stirring condition, solution A is added to solution B, a first reaction is carried out under a second stirring condition, formaldehyde is added, a second reaction is carried out, the solution is washed with water, and the solution is dried to prepare microcapsules loaded with fluorescent dye;

[0033] The preparation method of the polymer matrix comprises the following steps: reacting a polymer precursor, a curing agent and an accelerator to obtain the polymer matrix.

[0034] In some embodiments, the method for preparing the anti-corrosion coating satisfies one or more of the following characteristics:

[0035] (1) Calculated by feed amount, the volume mass ratio of the organic solvent containing ester groups and benzene rings to the polymer prepolymer in the raw materials for preparing the capsule wall is (10-50) mL / g;

[0036] (2) Based on the feed amount, the mass percentage concentration of the maleic anhydride copolymer solution is 0.3% to 0.6%;

[0037] (3) Based on the feed amount, the ratio of the maleic anhydride copolymer solution to the organic solvent containing an ester group and a benzene ring is (5-7): (2-3);

[0038] (4) The volume ratio of solution A to solution B is (2-3):(5-7);

[0039] (5) The mass percentage concentration of formaldehyde in the reaction system is 3%~5%.

[0040] In some embodiments, the method for preparing the anti-corrosion coating satisfies one or more of the following characteristics:

[0041] (1) The speed of the first stirring is 5000r / min ~7000r / min;

[0042] (2) The second stirring speed is 300r / min ~500r / min;

[0043] (3) The time for carrying out the first reaction is 5 min to 30 min;

[0044] (4) The temperature for carrying out the first reaction is 5°C to 30°C;

[0045] (5) The second reaction is carried out for 3 h to 6 h;

[0046] (6) The temperature for carrying out the second reaction is 45°C to 60°C.

[0047] In some embodiments, there is provided the use of the anti-corrosion coating or the anti-corrosion coating obtained by the preparation method in the preparation of an anti-corrosion coating with damage warning and repair tracking functions.

[0048] In some embodiments, an anti-corrosion coating with damage warning and repair tracking functions is provided, wherein the anti-corrosion coating comprises the anti-corrosion coating or the raw material of the anti-corrosion coating obtained by the preparation method is solidified.

[0049] The anti-corrosion coating provided comprises microcapsules loaded with fluorescent dyes and a polymer matrix containing reversible chemical bonds. The anti-corrosion coating prepared by using the anti-corrosion coating can realize damage warning and repair tracking. When the anti-corrosion coating is damaged, an obvious fluorescent warning signal appears in the damaged area, realizing damage warning of the coating. Then, under the action of heating, the broken reversible bonds are reconnected to repair the coating defects, and the warning signal disappears, making the coating repair process visualized. The anti-corrosion coating provided can not only sensitively warn of coating damage, but also track the damage repair process, realize multiple damage repairs of the coating, and significantly improve the service life of the coating, and has broad development and application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the implementation methods and examples of the present application and to more completely understand the present application and its beneficial effects, the following is a brief introduction to the drawings required for use in the description of the implementation methods or examples. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative work.

[0051] Figure 1 is a schematic diagram of a thermal reversible reaction of a DA bond in a specific embodiment;

[0052] Figure 2 is a scanning electron microscope image of the microcapsules prepared in Example 1;

[0053] Figure 3 The Bode diagram of the anti-corrosion coating prepared in Example 2 immersed in a 3.5 wt.% NaCl solution for 24 h;

[0054] Figure 4 is an image of the anti-corrosion coating in Example 2 under irradiation of ultraviolet light at 365 nm, wherein a is an image of the scratched anti-corrosion coating in Example 2 under irradiation of ultraviolet light at 365 nm, and b is an image of the repaired anti-corrosion coating in Example 2 under irradiation of ultraviolet light at 365 nm;

[0055] Figure 5 The Bode diagrams of the polyurethane coating lacking reversible chemical bonds in Comparative Example 1 immersed in a 3.5 wt.% NaCl solution for 24 h are the complete coating, the scratched coating, and the repaired coating. DETAILED DESCRIPTION

[0056] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0057] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0058] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0059] The terms "and / or", "or / and", and "and / or" used in this application include any one of two or more related listed items, and also include any and all combinations of related listed items, and the arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. It should be noted that when at least three items are connected by at least two conjunctions selected from "and / or", "or / and", and "and / or", it should be understood that in this application, the technical solution undoubtedly includes technical solutions that are all connected by "logical and", and undoubtedly includes technical solutions that are all connected by "logical or". For example, "A and / or B" includes three parallel solutions of A, B and "a combination of A and B".

[0060] In the present application, "plurality", "multiple", "multiple times", "multiples", etc., unless otherwise specified, refer to a number greater than 2 or equal to 2. For example, "one or more" means one or greater than or equal to two.

[0061] The terms "combination thereof", "any combination thereof", "any combination thereof" and the like used in this application include all suitable combinations of any two or more of the listed items.

[0062] In this application, the "suitable" mentioned in "suitable combination", "suitable method", "any suitable method", etc. is based on the ability to implement the technical solution of this application, solve the technical problems of this application, and achieve the expected technical effects of this application.

[0063] In the present application, "preferred", "better", "more preferred" and "suitable" are only used to describe implementation methods or examples with better effects. It should be understood that they do not constitute limitations on the scope of protection of the present application.

[0064] In the present application, "further", "further", "particularly" and the like are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of the present application.

[0065] In this application, "optionally", "optional", and "optional" mean optional or dispensable, that is, any one of the two parallel schemes of "yes" or "no". If multiple "options" appear in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "optional" is independent.

[0066] In the present invention, in the "first aspect", "second aspect", "third aspect", "fourth aspect", etc., the terms "first", "second", "third", "fourth", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", "fourth", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0067] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0068] In the present application, when it comes to numerical intervals (i.e., numerical ranges), unless otherwise specified, the optional numerical distribution is considered continuous within the above numerical interval, and includes the two numerical endpoints (i.e., the minimum and maximum values) of the numerical range, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to the integers within the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints. In this article, it is equivalent to directly listing each integer, such as t is an integer selected from 1 to 10, indicating that t is any integer selected from the group of integers consisting of 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10. In addition, when multiple ranges are provided to describe features or characteristics, these ranges can be combined. In other words, unless otherwise specified, the ranges disclosed herein should be understood to include any and all subranges included therein.

[0069] The temperature parameters in this application, unless otherwise specified, are allowed to be either constant temperature treatment or to vary within a certain temperature range. It should be understood that the constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument. Fluctuations within the range of ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are allowed.

[0070] In the present application, % (w / w) and wt% both represent weight percentage, % (v / v) refers to volume percentage, and % (w / v) refers to mass volume percentage.

[0071] The "room temperature" in this application generally refers to 5°C to 30°C, preferably 25±5°C.

[0072] In one embodiment, an anticorrosive coating is provided, comprising a polymer matrix containing reversible chemical bonds and microcapsules dispersed in the polymer matrix;

[0073] The microcapsule comprises a core material and a capsule wall covering the core material, wherein the core material comprises a fluorescent dye;

[0074] The reversible chemical bonds in the polymer matrix are one or more of Diels-Alder bonds, disulfide bonds and hydrogen bonds.

[0075] In one embodiment, in the anti-corrosion coating provided, the raw materials for preparing the capsule wall include polymer prepolymer, organic solvent containing ester group and benzene ring, urea, ammonium chloride, phenol organic matter, maleic anhydride copolymer and formaldehyde.

[0076] In one embodiment, in the anti-corrosion coating provided, the polymer prepolymer includes one or more of a polyurethane prepolymer, a polyurea-formaldehyde prepolymer, a polyurethane / urea-formaldehyde prepolymer and a polymethyl methacrylate prepolymer.

[0077] In one embodiment, in the anti-corrosion coating provided, the polymer prepolymer in the raw material for preparing the capsule wall of the microcapsule is a polyurethane prepolymer.

[0078] In one embodiment, the polyurethane prepolymer in the raw material for preparing the capsule wall of the microcapsule includes any one of Desmodur L75 (purchased from Covestro AG), Desmodur L60 (purchased from Covestro AG), Elastospray L 100 (purchased from BASF AG), and Arcol PU 3000 (purchased from Arco Chemicals).

[0079] In one embodiment, in the anti-corrosion coating provided, in the raw materials for preparing the capsule wall of the microcapsule, the organic solvent containing an ester group and a benzene ring comprises one or more of ethyl phenylacetate and phenyl acetate.

[0080] In one embodiment, in the anti-corrosion coating provided, the phenolic organic matter in the raw materials for preparing the capsule wall of the microcapsule comprises one or more of resorcinol, phenol and catechol.

[0081] In one embodiment, in the anti-corrosion coating provided, in the raw materials for preparing the capsule wall of the microcapsule, the maleic anhydride copolymer includes one or more of vinyl maleic anhydride copolymer and styrene maleic anhydride copolymer.

[0082] In one embodiment, the average molecular weight of the vinyl maleic anhydride copolymer is 300,000-500,000, for example, 300,000, 400,000, 500,000.

[0083] In one embodiment, in the anti-corrosion coating provided, the fluorescent dye included in the core material of the microcapsule is one or more of 2',7'-dichlorofluorescein, 2',7'-difluorofluorescein, crystal violet lactone, and fluorescein isothiocyanate.

[0084] In one embodiment, in the anti-corrosion coating provided, the raw materials for preparing the polymer matrix include a polymer precursor, a curing agent and an accelerator.

[0085] In one embodiment, in the anti-corrosion coating provided, the polymer precursor in the raw material for preparing the polymer matrix is ​​one or more of polyurethane prepolymer, furfuryl glycidylamine, epoxy resin prepolymer and phenolic resin prepolymer.

[0086] In one embodiment, in the anti-corrosion coating provided, the curing agent in the raw material for preparing the polymer matrix is ​​one or more of an amine curing agent containing an amino group, an adhesive containing an isocyanate group, and a curing agent containing an ester group.

[0087] In one embodiment, the amine curing agent is selected from one or more of polyetheramine, polyamide, aliphatic amine, and aromatic amine.

[0088] In one embodiment, the adhesive containing an isocyanate group is selected from one or more of toluene diisocyanate, isophorone diisocyanate, and dimethyltriphenylmethane tetraisocyanate.

[0089] In one embodiment, the ester-containing curing agent is selected from one or more of vinyl acetate, propylene carbonate, and methyl methacrylate.

[0090] In one embodiment, in the anti-corrosion coating provided, the accelerator in the raw material for preparing the polymer matrix is ​​one or more of furan, maleimide, and organic matter containing a thiol group.

[0091] In one embodiment, in the anti-corrosion coating provided, the mass ratio of the polymer precursor and the curing agent in the raw materials for preparing the polymer matrix is ​​(5-20): (1-5) based on the feed amount.

[0092] In one embodiment, in the anti-corrosion coating provided, the mass ratio of the polymer precursor and the accelerator in the raw materials for preparing the polymer matrix is ​​(5-20): (1-25) based on the feed amount.

[0093] In one embodiment, in the anti-corrosion coating provided, the reversible chemical bonds in the polymer matrix are Diels-Alder bonds. Figure 1 The figure shows the schematic diagram of the thermal reversible reaction of the DA bond, which consists of Figure 1 It can be found that the DA bond is a thermally reversible dynamic covalent bond. After heat treatment, a DA reverse reaction occurs, causing the DA bond to break. After cooling, a DA reaction occurs, causing the DA bond to reconnect.

[0094] In one embodiment, the polymer matrix is ​​one or more of an epoxy polymer matrix containing Diels-Alder bonds and a polyurethane matrix containing Diels-Alder bonds.

[0095] In one embodiment, in the anti-corrosion coating provided, the preparation method of the epoxy polymer matrix containing Diels-Alder bonds includes: reacting the epoxy monomer with an amine, followed by alkaline solution treatment, and then extracting the resulting emulsion to obtain furfuryl glycidylamine, and then reacting with an accelerator and a curing agent to form a stable epoxy coating structure.

[0096] In one embodiment, in the anti-corrosion coating provided, in the method for preparing the epoxy polymer matrix containing Diels-Alder bonds, the mass ratio of furfuryl glycidylamine, curing agent, and accelerator is (5~20): (1~5): (1~25).

[0097] In one embodiment, in the anti-corrosion coating provided, in the preparation method of the epoxy polymer matrix containing Diels-Alder bonds: the epoxy monomer includes any one of ethylene oxide, epichlorohydrin, propylene oxide, butylene oxide, bisphenol A type epoxy resin, and glycidyl ethers; the amine includes one or more of aniline, methylaniline, furfuralamine, thiophenylamine, and furfurylamine; wherein the mass ratio of the epoxy monomer to the amine is (7~9):(3~5).

[0098] In one embodiment, in the method for preparing an epoxy polymer matrix containing Diels-Alder bonds in the anti-corrosion coating provided, the alkali solution is any one of KOH aqueous solution, NaOH aqueous solution, and ammonia water.

[0099] In one embodiment, in the method for preparing an epoxy polymer matrix containing Diels-Alder bonds in the anti-corrosion coating provided, the extractant is any one of ethyl acetate, toluene, and dichloromethane.

[0100] In one embodiment, in the anti-corrosion coating provided, in the preparation method of the epoxy polymer matrix containing Diels-Alder bonds: the accelerator is any one of N,N'-(4,4'-methylenediphenyl)bismaleimide, 4,4'-diaminodiphenyl ether bismaleimide, bisallyl bismaleimide, and N-allylmaleimide.

[0101] In one embodiment, in the method for preparing an epoxy polymer matrix containing Diels-Alder bonds in the anti-corrosion coating provided, the curing agent is any one of tetraethylenepentamine, diethylenetriamine, triethylenetetramine, polyetheramine, and polyamide.

[0102] In one embodiment, a method for preparing a polyurethane matrix containing Diels-Alder bonds comprises: mixing an accelerator and a curing agent, adding a furan-terminated polyurethane prepolymer, and performing a cycloaddition reaction to prepare a polyurethane matrix containing Diels-Alder bonds.

[0103] In one embodiment, in the method for preparing a polyurethane matrix containing Diels-Alder bonds, the mass ratio of the furan-terminated polyurethane prepolymer, the curing agent, and the accelerator is (5-20): (1-5): (1-25).

[0104] In one embodiment, in the method for preparing a polyurethane matrix containing Diels-Alder bonds, the reaction temperature for the cycloaddition reaction is 60°C to 70°C.

[0105] In one embodiment, in the method for preparing a polyurethane matrix containing Diels-Alder bonds, the reaction time for the cycloaddition reaction is 20 hours to 30 hours.

[0106] In one embodiment, in the anti-corrosion coating provided, the particle size of the microcapsules is 10 μm to 50 μm, for example, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm.

[0107] In one embodiment, in the anti-corrosion coating provided, the weight ratio of the microcapsules to the polymer matrix, measured by the amount of feed, can be (0.1-10):100, or can be (0.5-5):100, for example, 0.1:100, 0.5:100, 1:100, 2:100, 3:100, 4:100, 5:100, 6:100, 7:100, 8:100, 9:100, 10:100.

[0108] In one embodiment, in the anti-corrosion coating provided, the mass ratio of urea, ammonium chloride and resorcinol in the raw materials for preparing the capsule wall of the microcapsule can be (9-12): (0.9-3): (0.9-2), or can be (9-12): (1-3): (1-2), for example, 9:0.9:0.9, 12:3:2, 9:3:2, 9:1:2, 9:3:1.

[0109] In one embodiment, in the anti-corrosion coating provided, in the raw materials for preparing the microcapsules, the mass ratio of the polymer prepolymer in the core material and the capsule wall to the organic solvent containing an ester group and a benzene ring, measured by feed amount, can be (3-6): (80-100): (200-300), or can be (3-4): (90-100): (200-300), for example, 3:80:200, 3:90:200, 4:90:250, 5:90:250, 6:90:300, 3:100:300, 6:100:300.

[0110] In one embodiment, a method for preparing an anti-corrosion coating is provided, comprising mixing microcapsules loaded with fluorescent dyes and a polymer matrix containing reversible chemical bonds to prepare the anti-corrosion coating.

[0111] In one embodiment, in the method for preparing the anticorrosive coating, the method for preparing the microcapsules comprises the following steps:

[0112] The core material, the polymer prepolymer and the organic solvent containing an ester group and a benzene ring are mixed to prepare a solution A.

[0113] Mixing urea, ammonium chloride, phenolic organic matter and maleic anhydride copolymer solution, adjusting the pH to 3.2-3.8, to prepare solution B;

[0114] Under the first stirring condition, solution A is added to solution B, a first reaction is carried out under the second stirring condition, formaldehyde is added, a second reaction is carried out, the solution is washed with water, and dried to prepare microcapsules loaded with fluorescent dye.

[0115] In one embodiment, in the method for preparing the anti-corrosion coating, the method for preparing the polymer matrix comprises the following steps: reacting a polymer precursor, a curing agent and an accelerator to obtain the polymer matrix.

[0116] In one embodiment, in the preparation method of the anti-corrosion coating, the volume mass ratio of the organic solvent containing ester groups and benzene rings to the polymer prepolymer in the raw materials for preparing the capsule wall of the microcapsule is (10~50) mL / g, for example, 10 mL / g, 20 mL / g, 30 mL / g, 40 mL / g, 50 mL / g.

[0117] In one embodiment, in the method for preparing the anti-corrosion coating, the mass percentage concentration of the maleic anhydride copolymer solution is 0.3% to 0.6% based on the feed amount.

[0118] In one embodiment, in the method for preparing the anti-corrosion coating, the ratio of the maleic anhydride copolymer solution to the organic solvent containing an ester group and a benzene ring is (5-7): (2-3) based on the feed amount.

[0119] In one embodiment, in the method for preparing the anti-corrosion coating, the volume ratio of solution A to solution B is (2-3):(5-7).

[0120] In one embodiment, in the method for preparing the anti-corrosion coating, the mass percentage concentration of formaldehyde in the reaction system is 3% to 5%.

[0121] In one embodiment, in the preparation method of the anti-corrosion coating, the first stirring rotation speed is 5000 r / min~7000 r / min, for example, 5000 r / min, 5500 r / min, 6000 r / min, 6500 r / min, 7000 r / min.

[0122] In one embodiment, in the preparation method of the anti-corrosion coating, the second stirring rotation speed is 300 r / min~500 r / min, for example, 300 r / min, 350 r / min, 400 r / min, 450 r / min, 500 r / min.

[0123] In one embodiment, in the method for preparing the anti-corrosion coating, the time for carrying out the first reaction is 5 min to 30 min, for example, 5 min, 10 min, 15 min, 20 min, 25 min, 30 min.

[0124] In one embodiment, in the method for preparing the anti-corrosion coating, the temperature for carrying out the first reaction is 5°C to 30°C, for example, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C.

[0125] In one embodiment, in the method for preparing the anti-corrosion coating, the time for carrying out the second reaction is 3h~6h.

[0126] In one embodiment, in the method for preparing the anti-corrosion coating, the temperature for carrying out the second reaction is 45°C to 60°C, for example, 45°C, 50°C, 55°C, 60°C.

[0127] In one embodiment, there is provided a use of the anti-corrosion coating or the anti-corrosion coating obtained by the preparation method in preparing an anti-corrosion coating with damage warning and repair tracking functions.

[0128] In one embodiment, an anti-corrosion coating with damage warning and repair tracking functions is provided, wherein the anti-corrosion coating comprises the anti-corrosion coating or the raw materials of the anti-corrosion coating obtained by the preparation method are solidified.

[0129] The anti-corrosion coating provided after curing has the dual functions of self-warning and self-repairing, which can not only timely warn of coating damage, but also repair coating damage to achieve long-term service of the coating. By means of pH changes, corrosion reactions, etc., reactions between chemical substances are achieved, and the anti-corrosion coating produces color or fluorescent warning signals, which is convenient for timely detection of coating damage, so as to repair the coating before failure. By introducing reversible chemical bonds and repairing coating damage under heating conditions, the sudden failure of the material structure is avoided. The sensitivity of damage warning is further improved, the repair process of the coating is tracked with the help of fluorescent signals, and multiple damage-repair of the coating can be achieved, which greatly improves the safety and service performance of metal materials and provides new ideas for the development of intelligent anti-corrosion coatings.

[0130] When the coating is damaged, the surface roughness of the damaged area of ​​the coating increases, and the reflection of light is significantly enhanced, showing the phenomenon of enhanced fluorescence, which realizes sensitive early warning of coating damage. Under the action of heating, the reversible chemical bonds in the coating are first broken and then reorganized. While repairing the coating damage, the roughness of the coating surface decreases, and the fluorescence weakens until it disappears, realizing the visualization of the coating damage repair process. The anti-corrosion coating provided does not consume the coating matrix during the repair process, and can achieve cyclic damage-repair, greatly improving the service life of the coating, and promoting the research and development and application of intelligent coatings.

[0131] The present invention is described in detail below in conjunction with the accompanying drawings and embodiments. The following embodiments are illustrative, not restrictive, and the protection scope of the present invention cannot be limited by the following embodiments.

[0132] The polyurethane prepolymer used in the embodiment is Desmodur L75, purchased from Covestro AG; the polytetrahydrofuran has a purity of 99.5%, a molecular weight of 305.43, and a chemical formula of C 16 H 33 O5X2 was purchased from Aladdin, model (terathane(R)1400); polyethylene grafted maleic anhydride, average molecular weight 400000, was purchased from Sigma-Aladdin Reagent Co., Ltd.

[0133] Example 1

[0134] 1. Take 0.03 g of crystal violet lactone and 0.9 g of polyurethane prepolymer and dissolve them in 24 mL of ethyl phenylacetate. Disperse them evenly as solution A. Dissolve 0.9 g of urea, 0.09 g of ammonium chloride and 0.09 g of resorcinol in 55 mL of 0.5 wt.% polyethylene grafted maleic anhydride aqueous solution. Disperse them evenly and adjust the pH to 3.4 with 0.1 M NaOH as solution B.

[0135] 2. At a speed of 5000 r / min, solution A was added dropwise into solution B to obtain a uniform mixture, and then the mixed solution was reacted at room temperature for 10 min at a speed of 350 r / min, and then 2.7 mL of formaldehyde solution was added, and the temperature was raised to 50 °C and the reaction was continued for 4 h. After the reaction, the emulsion was rinsed with deionized water for 6 times, filtered, and placed in a vacuum freeze dryer for 36 h to obtain the final microcapsules;

[0136] 3. 5 g of polytetrahydrofuran, 4.5 g of isophorone diisocyanate, 7.5 mL of N,N-dimethylformamide, and 0.06 g of dibutyltin dilaurate were reacted at 70 °C for 4 h at a speed of 260 r / min, and then the temperature was raised to 75 °C and 0.98 g of furfuryl alcohol was added to continue the reaction for 5 h to obtain a furan-terminated polyurethane prepolymer;

[0137] 4. Dissolve 1.8 g of bismaleimide in 2.5 mL of N,N-dimethylformamide, add it to the furan-terminated polyurethane prepolymer, cool to 70 °C and continue to react for 24 h to obtain a polyurethane matrix with DA bonds;

[0138] 5. Add 2 wt.% microcapsules to the polyurethane coating, vortex for 7 min, and then cure at 80 °C for 40 h. The coating thickness after curing is 80 µm.

[0139] Figure 1 The figure shows the schematic diagram of the thermal reversible reaction of the DA bond, which consists of Figure 1 It can be found that the DA bond is a thermally reversible dynamic covalent bond. After heat treatment, a DA reverse reaction occurs, causing the DA bond to break. After cooling, a DA reaction occurs, causing the DA bond to reconnect.

[0140] The microcapsules loaded with crystal violet lactone were prepared using a Czech TESCAN MIRA4 scanning electron microscope. Figure 2 As shown. Figure 2 It can be found that the microcapsules are spherical in structure and uniform in size, with an average particle size of about 20 µm.

[0141] Example 2

[0142] 1. Take 0.04 g 2',7'-dichlorofluorescein and 1 g polyurethane prepolymer and dissolve them in 27 mL ethyl phenylacetate. Disperse them evenly as solution A. Dissolve 1.1 g urea, 0.1 g ammonium chloride and 0.1 g resorcinol in 65 mL 0.6 wt.% polyethylene grafted maleic anhydride aqueous solution. Disperse them evenly and adjust the pH to 3.5 with 0.2 M NaOH. This is solution B.

[0143] 2. At a speed of 7000 r / min, solution A was added dropwise into solution B to obtain a uniform mixture, and then the mixed solution was reacted at room temperature for 9 min at a speed of 450 r / min, and then 2.9 mL of formaldehyde solution was added, and the temperature was raised to 55 °C and the reaction was continued for 4.5 h. After the reaction, the emulsion was rinsed 8 times with deionized water, filtered, and placed in an oven for 24 h to obtain the final microcapsules;

[0144] 3. Heat 75 g of epichlorohydrin to 40 °C, add 39 g of furfurylamine, raise the temperature to 60 °C, react at 300 rpm for 5 h, cool the system to room temperature, add 128 mL of NaOH aqueous solution, continue to react at 300 °C for 5 h, and obtain a completely reacted emulsion;

[0145] 4. The emulsion was extracted with 160 mL of ethyl acetate and washed with deionized water for 5 times to remove impurities to obtain furfuryl glycidyl amine. Furfuryl glycidyl amine: N, N'-(4, 4'-methylenediphenyl) bismaleimide (molar ratio of 2:1) was taken, magnetically stirred at 400 rpm for 7 min, and then 8 phr of tetraethylene pentamine was added and stirred at 800 rpm for 3 min to obtain an epoxy polymer matrix containing DA bonds;

[0146] 5. Add 3 wt.% microcapsules to the epoxy coating, vortex for 9 min, and then cure at 70 °C for 45 h. The coating thickness after curing is 90 µm.

[0147] Figure 3 The Bode plot of the anti-corrosion coating prepared in Example 2 immersed in 3.5 wt.% NaCl solution for 24 h was tested by electrochemical impedance spectroscopy, including the complete coating, the scratched coating and the repaired coating. The electrochemical test parameters are as follows: the test frequency range is 10 5 ~10 -2 Hz, the voltage perturbation amplitude was 20 mV, including the working electrode (Q235 steel plate), the counter electrode (platinum sheet, 1.5×1.5 cm 2 ), reference electrode (saturated calomel electrode). The scratch of the coating was made by a No. 11 scalpel with a width of about 80 μm, and the repair condition was heat treatment in an oven at 90 °C for 4 h. Figure 4 a is an image of the complete anti-corrosion coating prepared in Example 2 under irradiation with ultraviolet light at 365 nm, Figure 4 b is an image of the anti-corrosion coating prepared in Example 2 after being scratched under irradiation of ultraviolet light at 365 nm.

[0148] Figure 3 It can be found that the low-frequency impedance modulus of the complete coating (|Z| 0.01Hz ) reached 1010 Ω·cm 2 , with excellent shielding properties. When the coating is damaged, |Z| 0.01Hz The value drops rapidly, and the corrosion process intensifies. It is worth noting that the |Z| 0.01Hz The value is very close to that of the complete coating, which effectively restores the integrity and anti-corrosion effect of the coating, indicating its excellent self-healing ability.

[0149] Figure 4 It can be found that the intact area of ​​the coating appears light yellow. When the coating is damaged, obvious fluorescence aggregation appears to highlight the coating damage. When the coating is repaired, the fluorescence aggregation phenomenon disappears and returns to its original state.

[0150] Comparative Example 1

[0151] This comparative example provides an anti-corrosion coating without reversible chemical bonds and a preparation method thereof, which specifically comprises the following steps:

[0152] 1. Take 0.04 g 2',7'-dichlorofluorescein and 0.9 g polyurethane prepolymer and dissolve them in 25 mL ethyl phenylacetate. Disperse them evenly as solution A. Dissolve 1.2 g urea, 0.15 g ammonium chloride and 0.15 g catechol in 60 mL 0.5wt.% polyethylene grafted maleic anhydride aqueous solution. Disperse them evenly and adjust the pH to 3.45 with 0.15 M NaOH. This is solution B.

[0153] 2. At a speed of 6000 r / min, solution A was added dropwise into solution B to obtain a uniform mixture, and then the mixed solution was reacted at room temperature for 11 min at a speed of 400 r / min, and then 2.8 mL of formaldehyde solution was added, and the temperature was raised to 55 °C and the reaction was continued for 4 h. After the reaction, the emulsion was rinsed with deionized water 7 times, filtered, and placed in a vacuum freeze dryer for 48 h to obtain the final microcapsules;

[0154] 3. Take 1.7 g of component 1 and 2 g of component 2 of polyurethane varnish (TS01-3), mix them thoroughly under a magnetic stirrer at 500 rpm, add 4 wt.% microcapsules to the mixed solution, vortex oscillate for 8 min, and then cure at 80 °C for 10 h. The coating thickness after curing is 80 µm.

[0155] Figure 5 The Bode diagrams of the polyurethane coating lacking reversible chemical bonds in Comparative Example 1 immersed in 3.5 wt.% NaCl solution for 24 h are shown, including the intact coating, the scratched coating, and the repaired coating. The scratch width of the coating is about 80 μm, and the repair condition is heat treatment in a 90 ℃ oven for 4 h. As can be seen from the figure, the low-frequency impedance modulus (|Z|0.01Hz ) reached 10 10 Ω·cm 2 , has a good protective effect. When the coating is damaged, |Z| 0.01Hz The value decreases rapidly, which is the same as the change law of coating performance in Example 3. However, the |Z| 0.01Hz Values ​​and |Z| of scratched coating 0.01Hz The values ​​are not much different, indicating that the repair treatment has no effect on the recovery of coating performance, which is due to the lack of reversible chemical bonds in the coating. Therefore, the embedding of reversible chemical bonds is necessary to improve the self-healing efficiency of the coating.

[0156] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0157] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims, and the description and drawings may be used to interpret the content of the claims.

Claims

1. An anticorrosive coating, characterized in that: It includes a polymer matrix containing reversible chemical bonds and microcapsules dispersed in the polymer matrix; The microcapsule comprises a core material and a capsule wall covering the core material, wherein the core material comprises a fluorescent dye; The reversible chemical bonds in the polymer matrix are one or more of Diels-Alder bonds, disulfide bonds and hydrogen bonds.

2. The anticorrosive coating according to claim 1, characterized in that: Meet one or more of the following characteristics: (1) The raw materials for preparing the capsule wall include polymer prepolymers, organic solvents containing ester groups and benzene rings, urea, ammonium chloride, phenolic organic matter, maleic anhydride copolymers and formaldehyde; the polymer prepolymers include one or more of polyurethane prepolymers, polyurea-formaldehyde prepolymers, polyurethane / urea-formaldehyde prepolymers and polymethyl methacrylate prepolymers. Optionally, the polymer prepolymer in the raw materials for preparing the capsule wall is a polyurethane prepolymer; (2) The fluorescent dye is one or more of 2',7'-dichlorofluorescein, 2',7'-difluorofluorescein, crystal violet lactone, and fluorescein isothiocyanate; (3) The particle size of the microcapsule is 10 μm to 50 μm.

3. The anticorrosive coating according to claim 1 or 2, characterized in that: The raw materials for preparing the polymer matrix include a polymer precursor, a curing agent and an accelerator; Optionally, the raw materials for preparing the polymer matrix meet one or more of the following characteristics: (1) The polymer precursor in the raw material for preparing the polymer matrix is ​​one or more of polyurethane prepolymer, furfuryl glycidyl amine, epoxy resin prepolymer and phenolic resin prepolymer; (2) The curing agent in the raw material for preparing the polymer matrix is ​​one or more of an amine curing agent containing an amino group, an adhesive containing an isocyanate group, and a curing agent containing an ester group; optionally, the amine curing agent is selected from one or more of polyetheramine, polyamide, aliphatic amine, and aromatic amine; optionally, the adhesive containing an isocyanate group is selected from one or more of toluene diisocyanate, isophorone diisocyanate, and dimethyltriphenylmethane tetraisocyanate; optionally, the curing agent containing an ester group is selected from one or more of vinyl acetate, propylene carbonate, and methyl methacrylate; (3) The accelerator in the raw material for preparing the polymer matrix is ​​one or more of furan, maleimide, and organic matter containing a thiol group; (4) In terms of feed amount, the mass ratio of the polymer precursor to the curing agent in the raw materials for preparing the polymer matrix is ​​(5-20): (1-5); (5) Calculated by feed amount, the mass ratio of the polymer precursor to the promoter in the raw materials for preparing the polymer matrix is ​​(5-20): (1-25).

4. The anticorrosive coating according to any one of claims 1 to 3, characterized in that: Meet one or more of the following characteristics: (1) Calculated by feed amount, the weight ratio of the microcapsule to the polymer matrix is ​​(0.1-10):100; (2) Calculated by feed amount, the mass ratio of urea, ammonium chloride and phenolic organic matter in the raw materials for preparing the capsule wall is (9-12): (0.9-3): (0.9-2); (3) In the raw materials for preparing the microcapsules, the mass ratio of the polymer prepolymer in the core material and the capsule wall to the organic solvent containing an ester group and a benzene ring is (3-6): (80-100): (200-300) based on the feed amount.

5. The anticorrosive coating according to any one of claims 1 to 4, characterized in that: Meet one or more of the following characteristics: (1) Calculated by feed amount, the weight ratio of the microcapsules to the polymer matrix is ​​(0.5-5):100; (2) Calculated by feed amount, the mass ratio of urea, ammonium chloride and phenolic organic matter in the raw materials for preparing the capsule wall is (9-12): (1-3): (1-2); (3) In the raw materials for preparing the microcapsules, the mass ratio of the polymer prepolymer in the core material and the capsule wall to the organic solvent containing an ester group and a benzene ring is (3-4): (90-100): (200-300) based on the feed amount.

6. The anticorrosive coating according to any one of claims 1 to 5, characterized in that: The polymer matrix is ​​one or more of an epoxy polymer matrix containing Diels-Alder bonds and a polyurethane matrix containing Diels-Alder bonds.

7. A method for preparing an anticorrosive coating, characterized in that: The method comprises mixing microcapsules and a polymer matrix to prepare the anticorrosive coating according to any one of claims 1 to 6; wherein: The preparation method of the microcapsules comprises the following steps: The core material, the polymer prepolymer and the organic solvent containing an ester group and a benzene ring are mixed to prepare a solution A. Mixing urea, ammonium chloride, phenolic organic matter and maleic anhydride copolymer solution, adjusting the pH to 3.2-3.8, to prepare solution B; Under a first stirring condition, solution A is added to solution B, a first reaction is carried out under a second stirring condition, formaldehyde is added, a second reaction is carried out, the solution is washed with water, and the solution is dried to prepare microcapsules loaded with fluorescent dye; The preparation method of the polymer matrix comprises the following steps: reacting a polymer precursor, a curing agent and an accelerator to obtain the polymer matrix.

8. The preparation method according to claim 7, characterized in that: Meet one or more of the following characteristics: (1) Calculated by feed amount, the volume mass ratio of the organic solvent containing ester groups and benzene rings to the polymer prepolymer in the raw materials for preparing the capsule wall is (10-50) mL / g; (2) Based on the feed amount, the mass percentage concentration of the maleic anhydride copolymer solution is 0.3% to 0.6%; (3) Based on the feed amount, the ratio of the maleic anhydride copolymer solution to the organic solvent containing an ester group and a benzene ring is (5-7): (2-3); (4) The volume ratio of solution A to solution B is (2-3):(5-7); (5) The mass percentage concentration of formaldehyde in the reaction system is 3%~5%.

9. The preparation method according to claim 7 or 8, characterized in that: Meet one or more of the following characteristics: (1) The speed of the first stirring is 5000r / min ~7000r / min; (2) The second stirring speed is 300r / min ~500r / min; (3) The time for carrying out the first reaction is 5 min to 30 min; (4) The temperature for carrying out the first reaction is 5°C to 30°C; (5) The second reaction is carried out for 3 h to 6 h; (6) The temperature for carrying out the second reaction is 45°C to 60°C.

10. Use of the anti-corrosion coating according to any one of claims 1 to 5 or the anti-corrosion coating obtained by the preparation method according to any one of claims 6 to 9 in the preparation of an anti-corrosion coating with damage warning and repair tracking functions.

11. An anti-corrosion coating with damage warning and repair tracking functions, characterized in that: The anti-corrosion coating is obtained by curing the raw materials of the anti-corrosion coating according to any one of claims 1 to 5 or the anti-corrosion coating obtained by the preparation method according to any one of claims 6 to 9.

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