Preparation method of rosin derivative modified fluorescent double-shell isocyanate-based self-repairing microcapsule and application of microcapsule in coating field

Abstract

The invention provides a preparation method of a rosin derivative modified fluorescent double-shell isocyanate-based self-repairing microcapsule and application of the microcapsule in the field of paints.In the preparation method, a bio-based rosin derivative is adopted as a microcapsule core material, so that the microcapsule is green and environmentally friendly; by introducing the double-shell microcapsules, the coating material has a self-repairing function and a self-checking function, and the damaged area and the damaged degree of the coating can be found through ultraviolet irradiation; a rigid rosin structure is introduced, so that the mechanical property of polyurethane is remarkably enhanced, and the application field of the double-shell microcapsule is further expanded by blending modification of the double-shell microcapsule and other materials; and the corrosion resistance of the coating is enhanced under the combined action of fluorine and silicon elements on the surface of the microcapsule.

Description

Technical Field

[0001] The invention relates to the technical field of polyurethane material preparation, in particular to a preparation method of rosin derivative modified fluorescent double-shell isocyanate-based self-repairing microcapsules and application thereof in the coating field. Background Art

[0002] Coating materials are widely used in pipelines, walls, electronic equipment protection, marine anti-corrosion and anti-fouling, etc. Over time, coating materials may be affected by natural factors such as light and humidity and non-natural factors such as human damage, resulting in surface problems such as cracks, aging, and corrosion. If cracks are not repaired in time, the longer the time, the larger the cracks will be, aggravating the corrosion of the protected materials, and eventually leading to obvious cracking and peeling of the coating, or even completely losing its protective effect. In order to be able to detect the damaged area and the degree of damage in time, it is necessary to give the coating a self-detection damage characteristic. In order to repair the damaged area in time and prevent the damaged area from further expanding, it is necessary to give the coating a self-repairing function. Therefore, the research and development of self-repairing and self-detecting coating materials aims to extend the service life of coating materials, improve resource efficiency, and reduce maintenance costs, which is in line with the core concept of sustainable development in today's society.

[0003] Microcapsule technology is currently widely used in catalysis, self-healing materials, energy storage, biomedicine and other fields. The microcapsule polyurethane composite coating system contains micron-sized microcapsules and encapsulated self-healing agents. These microcapsules are dispersed throughout the system. When the coating is broken or damaged, the microcapsules will break and release the encapsulated self-healing agents stored inside. These restoring agents will then react chemically and physically with the surrounding environment or the coating substrate to repair the damaged part of the coating. This process slows down or stops the deterioration of the coating performance and enhances the durability and self-protection ability of the coating. However, in the prior art, the single structure of the self-healing microcapsule is difficult to cope with complex and changeable corrosion conditions, and the microcapsule core material contains mostly petroleum-based substances, and the rupture of the capsule may have a negative impact on the environment.

[0004] Therefore, it is very meaningful to provide a microcapsule core material synthesized by bio-based reactants for application in the field of coatings. Summary of the invention

[0005] In view of this, the present invention provides a preparation method of rosin derivative modified fluorescent double-shell isocyanate-based self-healing microcapsules and its application in the field of coatings, and uses bio-based rosin derivatives to synthesize microcapsule core materials to reduce ecological environmental pressure.

[0006] The present invention provides a method for preparing a rosin derivative modified fluorescent double-shell isocyanate-based self-repairing microcapsule, characterized in that it comprises:

[0007] Step 1: After mixing and stirring a polyol, isophorone diisocyanate and a solvent, a catalyst is added thereto for reaction to prepare an oil phase system; wherein the polyol is one of propylene pimarol, propylene pimaric acid (1-chloro-2-hydroxy) propanediol and maleic pimarol prepared from rosin as a raw material;

[0008] Step 2: stirring and dispersing the oil phase system, hexamethylene diisocyanate trimer and solvent to obtain an improved oil phase system;

[0009] Step 3: stirring and dispersing 4,4-bis(2-disulfonylphenyl)biphenyl and gum arabic in deionized water to obtain an aqueous phase system;

[0010] Step 4: adding the improved oil phase system dropwise into the water phase system and stirring to obtain an emulsion;

[0011] Step 5: adding 1,4-butanediol aqueous solution to the emulsion for reaction. After the reaction is completed, the obtained suspension is cooled freely, filtered, washed and dried to obtain single-shell microcapsule powder;

[0012] Step 6: Disperse the microcapsule powder in deionized water, add the ethanol solution of tetraethyl orthosilicate thereto, stir for reaction, add ammonia water to adjust the pH of the solution to 6, so that the tetraethyl orthosilicate is hydrolyzed to produce a silica shell, and then further stir for 40 minutes, add tridecafluorooctyltrimethoxysilane and react at 70°C for 4 hours; then cool to 40°C and continue to react for 12 hours. After the reaction is completed, the product is washed with deionized water and anhydrous ethanol, filtered, and dried to obtain a novel rosin derivative modified fluorescent double-shelled isocyanate-based self-healing microcapsule.

[0013] Preferably, the solvent is one or more of ethyl acetate, butyl acetate, xylene and cyclohexanone.

[0014] Preferably, the catalyst is one or more of stannous octoate, dibutyltin diacetate, triethylamine, tetrabutylammonium bromide, and dibutyltin dilaurate.

[0015] Preferably, the stirring parameters in step 1 are: heating and stirring at 300 r / min and 40° C., the amount of catalyst added is 0.08%-1% by mass, and after adding the catalyst, the reaction temperature is raised to 60° C. and the reaction is carried out for 5 hours to prepare the oil phase system.

[0016] Preferably, the reaction temperature in steps 2 and 3 is 25°C.

[0017] Preferably, the stirring parameters in step 4 are: stirring at 800 r / min for 15 min.

[0018] Preferably, the reaction parameters in step 5 are: 70° C., 500 r / min, and reaction time for 5 h.

[0019] The present invention also provides the use of the rosin derivative modified fluorescent double-shell isocyanate-based self-repairing microcapsules in the field of coatings, comprising the following steps:

[0020] Add polytetrahydrofuran, isophorone diisocyanate, 2,2-dihydroxymethylpropionic acid, N,N-dimethylformamide, and a catalyst with a mass fraction of 0.08-1% into a flask, react at 85°C for 2h, then add trimethylolpropane to react for 2h, cool to 40°C after the reaction, add triethylamine and ice deionized water, and emulsify at high speed at 2000r / min for 15min to obtain a WPU emulsion;

[0021] At room temperature, WPU emulsion and double-shell isocyanate-based self-healing microcapsules were mixed and stirred at 400 r / min. After standing, the emulsion was coated on a tinplate patch with a polished surface to obtain a new rosin derivative modified fluorescent double-shell isocyanate-based self-healing microcapsule / polyurethane composite coating.

[0022] The present invention provides a method for preparing rosin derivative modified fluorescent double-shell isocyanate-based self-repairing microcapsules and an application thereof in the field of coatings. In the preparation method, a bio-based rosin derivative is used as a microcapsule core material, which is green and environmentally friendly. The introduced double-shell microcapsules not only enable the coating material to have a self-repairing function, but also a self-detection function, and the damaged area and degree of the coating can be found by ultraviolet light irradiation. The rigid rosin structure is introduced to significantly enhance the mechanical properties of the polyurethane, and the double-shell microcapsules are blended and modified with other materials to further expand their application field. The combined action of fluorine and silicon elements on the surface of the microcapsules also enhances the corrosion resistance of the coating.

[0023] The preparation method of the present invention can improve the mechanical properties of waterborne polyurethane and provide it with self-damage detection and repair functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the synthesis of propylene rosin alcohol provided by the present invention;

[0025] Figure 2 It is a schematic diagram of the synthesis of maleopimarol provided by the present invention;

[0026] Figure 3 A schematic diagram of the synthesis of propylene pimaric acid (1-chloro-2-hydroxy) propanediol provided by the present invention;

[0027] Figure 4 This is a schematic diagram of the structure of the rosin derivative modified fluorescent double-shelled isocyanate-based self-healing microcapsule provided by the present invention. DETAILED DESCRIPTION

[0028] In order to solve the increasingly prominent problem of contradiction between population, resources and environment, improve the mechanical properties of waterborne polyurethane, and give it self-detection of damage and repair functions, the present invention provides a preparation method of rosin derivative modified fluorescent double-shell isocyanate-based self-repairing microcapsules and its application in the field of coatings, aiming to provide a novel synthesis method of rosin derivative modified fluorescent double-shell isocyanate-based self-repairing microcapsules to respond to the changing corrosion conditions, and use bio-based rosin derivatives to synthesize microcapsule core materials to reduce ecological environmental pressure.

[0029] First, a method for preparing rosin derivative modified fluorescent double-shell isocyanate-based self-healing microcapsules comprises:

[0030] (1) Using rosin as the most basic raw material, three bio-based polyols, namely, propylene pimaric acid (1-chloro-2-hydroxy) propanediol, and maleic pimaric acid, were prepared through different reactions and processes for use; the polyols, isophorone diisocyanate, and solvent were added to a flask, heated at 300 r / min and 40° C. with stirring, and then a catalyst with a mass fraction of 0.08% to 1% was added, the temperature was raised to 60° C., and the reaction was performed for 5 hours to obtain an oil phase system;

[0031] Preparation of acrylpimaric acid: According to the literature (Wan Guoyun, Wang Zhenguo, Su Jianxiong. Preparation of acrylic rosin polyester fiberglass from rosin [J]. Plastic Industry, 1987, (01): 30-32+2.), rosin and acrylic acid were added into a three-necked flask at a mass ratio of 4:25, and heated to 170℃ for 2h under nitrogen protection to isomerize the abietic acid in the rosin to generate L-pimaric acid. Then the temperature was raised to 225℃ for 2h. Since the conjugated double bond of L-pimaric acid is S-cis, it has high reaction activity, so it reacts with the dienophile acrylic acid to produce a light yellow transparent solid acrylpimaric acid. The structure of acrylpimaric acid is shown in the attached figure. Figure 1 .

[0032] Preparation of propylene pinomarine: dissolve propylene pinomarine acid in solvent 1, and slowly add a reducing agent under low temperature conditions and inert gas protection. After the reducing agent is added, react for 0.5 to 6 hours, and then heat to 40 to 80°C and react for 6 to 24 hours. After the reaction is completed, use a quencher to quench the excess reducing agent, then add deionized water and shake thoroughly, filter, and vacuum filter at 40 to 60°C to constant weight. Add a non-aqueous solvent to the constant weight filtrate, shake thoroughly, let stand to separate, remove the water layer, and perform high vacuum rotary evaporation on the oil-containing layer liquid to obtain a viscous liquid product with a diol structure - propylene pinomarine. Its structure is detailed in the attached Figure 1 .

[0033] The solvent 1 is preferably a mixed solvent of one or more of anhydrous tetrahydrofuran, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethyl ether, ethyl butyl ether, dihexyl ether, dipentyl ether, and 3-methylfuran.

[0034] The low temperature condition can be achieved by a liquid nitrogen quick freezing method, or by maintaining a temperature condition of -10°C to 15°C through a temperature control device.

[0035] The inert gas is preferably nitrogen or argon, or a mixture of the two.

[0036] The reducing agent is preferably one or more of lithium aluminum hydride, sodium borohydride, potassium borohydride or dibutylaluminum hydride.

[0037] The quenching agent is one or more of water, sodium hydroxide aqueous solution, sodium carbonate aqueous solution, sodium bicarbonate aqueous solution, hydrochloric acid solution or diethyl sulfuric acid solution.

[0038] The non-aqueous solvent is preferably a mixture of one or more of toluene, xylene, ethyl acetate and butyl acetate.

[0039] Preparation of maleopimaric acid: It is prepared by Diels-Alder reaction of rosin and maleic acid or maleic anhydride. According to the literature (Yin Hongmei, Guo Hong, Xu Feng, et al. Synthesis and application research of maleopimaric acid [J]. Journal of Shenyang Institute of Chemical Technology, 1998, (02): 15-21.), a certain amount of rosin and maleic anhydride are added to a three-necked flask, heated to 180℃ for 4-5h, and cooled to a light yellow solid. The powder is treated with carbon tetrachloride 2-3 times to remove the unreacted rosin, and then treated with water several times to remove the unreacted maleic anhydride to obtain a white powder product. Its structure is detailed in the attached Figure 2 . Rosin and maleopimaric acid in the carbon tetrachloride treatment solution can be recovered.

[0040] Preparation of maleopimaric acid: dissolve maleopimaric acid in solvent 1, and slowly add a reducing agent under the protection of inert gas at low temperature. After the reducing agent is added, react for 0.5 to 10 hours, and then heat to 40 to 80°C to react for 6 to 48 hours. After the reaction is completed, use a quencher to quench the excess reducing agent, then add deionized water and shake thoroughly, filter, and vacuum filter at 40 to 60°C to constant weight. Add a non-aqueous solvent to the constant weight filtrate, shake thoroughly, let stand to separate, remove the water layer, and perform high vacuum rotary evaporation on the oil-containing layer liquid to obtain a product with a triol structure - maleopimaric acid. Its structure is detailed in the attached Figure 2 .

[0041] The preparation method of propylene pimaric acid (1-chloro-2-hydroxy) propanediol is as follows: dissolve propylene pimaric acid in a non-aqueous solvent, add epichlorohydrin, add a promoter, and react at 40-110°C for 0.5-48h. After the reaction is completed, add deionized water, shake thoroughly, stand for stratification, remove the water layer, and perform high vacuum rotary evaporation on the oil layer liquid to obtain propylene pimaric acid (1-chloro-2-hydroxy) propanediol. The structure of the propylene pimaric acid is shown in the attached figure. Figure 3 .

[0042] Specifically, the amount of the non-water-soluble solvent is 3 to 200 wt % of the mass of acrylpimaric acid, preferably 10 to 50 wt %;

[0043] Specifically, the mass ratio of acrylpimaric acid to epichlorohydrin is 1:1.05 to 1.50, preferably 1:1.10 to 1.20;

[0044] Specifically, the amount of the accelerator added is 0.5 to 3.5 wt % of the total mass of acrylpimaric acid and epichlorohydrin, preferably 0.8 to 1.5 wt %;

[0045] Specifically, in order to improve the reaction conversion rate, the promoter is preferably added in multiple times, and the best number of additions is 3-4 times. The first addition is 1 / 2 of the total amount of promoter, and the remaining additions are 1 / 2 of the remaining amount of promoter until all the promoter is added.

[0046] The non-aqueous solvent is preferably a mixture of one or more of toluene, xylene, ethyl acetate, butyl acetate, dichloromethane, dichloroethane, chloroform, carbon tetrachloride, trichloroethylene, and dichloroethylene.

[0047] The accelerator is a mixture of one or more of tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium hydrogen sulfate, tetrabutylammonium fluoride, and tetrabutylammonium hydroxide, wherein tetrabutylammonium bromide and tetrabutylammonium chloride are preferred;

[0048] (2) The oil phase system obtained in the above step, hexamethylene diisocyanate trimer and solvent are stirred and dispersed at 25° C. to obtain an improved oil phase system; in the oil phase system, HDI trimer can be used as a modifier to improve the dispersion stability of other raw materials in the oil phase and prevent precipitation and aggregation.

[0049] (3) stirring and dispersing 4,4-bis(2-disulfonylphenyl)biphenyl and gum arabic in deionized water at 25° C. to produce an aqueous phase system;

[0050] (4) The emulsion was obtained by dropping the oil phase system into the water phase system and stirring at 800 r / min for 15 min. The emulsion was added to a flask, 1,4-butanediol (with deionized water) was added to dissolve, and then the system was reacted at 70°C and 500 r / min for 5 h. After the reaction was completed, the suspension was cooled freely, then filtered, washed with anhydrous ethanol and water, and dried to obtain a single-shell microcapsule powder;

[0051] (5) Disperse the microcapsule powder in deionized water and transfer it to a flask. Dissolve the tetraethyl orthosilicate with an equal weight of anhydrous ethanol to prepare a tetraethyl orthosilicate solution, pour it into the flask containing the microcapsules, stir at 50°C and 500r / min for 30 minutes, add ammonia water to adjust the pH to 6, so that the tetraethyl orthosilicate is hydrolyzed to produce a silica shell, and then further stir for 40 minutes, add tridecafluorooctyltrimethoxysilane and react at 70°C for 4 hours. Then cool to 40°C and continue the reaction for 12 hours. After the reaction is completed, the product is washed with deionized water and anhydrous ethanol, filtered, and dried to obtain a new type of rosin derivative modified fluorescent double-shelled isocyanate-based self-healing microcapsules;

[0052] The present invention introduces the rosin three-membered phenanthrene ring structure into the linear main chain structure of polyurethane by reacting the bio-based polyol prepared by rosin derivatives with diisocyanate, which not only retains the rigid structural characteristics of rosin but also retains the good flexibility of the aliphatic six-membered ring non-planar structure compared with the traditional carbon chain structure. The present invention is based on the isocyanate capsule core and the first protective shell (including fluorescent agent). The second shell is a second hydrophobic shell prepared by using fluorinated silane.

[0053] When the shell of the microcapsule wrapping the inner core material is damaged and the inner core material flows out, the isocyanate capsule core can achieve self-repair by participating in the reaction with water and oxygen in the air without the need for other external conditions. At the same time, the capsule is broken to expose the fluorescent agent embedded in advance, and the damaged position and degree of the material can be directly observed by ultraviolet light irradiation. Based on the isocyanate capsule core, it is modified with tridecafluorooctyltrimethoxysilane to prepare a new rosin derivative-modified fluorescent double-shell isocyanate-based self-healing microcapsule with anti-corrosion, hydrophobicity, fluorescence detection and other properties, and it is added to water-based polyurethane to prepare a self-healing coating.

[0054] The fluorescent double-shell isocyanate-based self-healing microcapsules modified by the above rosin derivatives were added into a flask, polytetrahydrofuran, isophorone diisocyanate, 2,2-dihydroxymethyl propionic acid, N,N-dimethylformamide, and a catalyst with a mass fraction of 0.08-1% were added into the flask, reacted at 85°C for 2h, and then trimethylolpropane was added to react for 2h. After the reaction was completed, the temperature was lowered to 40°C, triethylamine and ice deionized water were added, and high-speed emulsification was carried out at 2000r / min for 15min to obtain WPU emulsion.

[0055] At room temperature, the prepared WPU emulsion and double-shell microcapsules were added to a beaker and stirred at 400 r / min. After standing for a period of time, the emulsion was coated on a tinplate patch with a polished surface to obtain a new rosin derivative modified fluorescent double-shell isocyanate-based self-healing microcapsule / polyurethane composite coating.

[0056] The solvent is one or more of ethyl acetate, butyl acetate, xylene and cyclohexanone, preferably cyclohexanone and ethyl acetate.

[0057] The catalyst is one or more of stannous octoate, dibutyltin diacetate, triethylamine, tetrabutylammonium bromide, and dibutyltin dilaurate, preferably dibutyltin dilaurate.

[0058] Example 1

[0059] (1) 6.92 g of propylene pinamarin and 26.6 g of isophorone diisocyanate were added to a cyclohexanone solvent, heated at 300 rpm and 40° C. with stirring, and then 0.08-1% by mass of dibutyltin dilaurate was added, the temperature was raised to 60° C., and the reaction was carried out for 5 hours to obtain an oil phase system;

[0060] (2) 17.6 g of the oil phase system, 1.64 g of hexamethylene diisocyanate trimer and 10 g of ethyl acetate were stirred and dispersed at 25° C. to obtain an improved oil phase system;

[0061] (3) 3 wt % 4,4-bis(2-disulfonylphenyl)biphenyl and 7.2 g gum arabic were dispersed in deionized water at 25° C. to produce an aqueous phase system;

[0062] (4) The improved oil phase system was added dropwise to the water phase system and stirred at 800 r / min for 15 min to obtain an emulsion.

[0063] (5) The emulsion was added to a flask, 0.36 g of 1,4-butanediol (dissolved in deionized water) was added, and the system was reacted at 70°C and 500 r / min for 5 h. After the reaction, the suspension was cooled freely, then filtered, washed with anhydrous ethanol and water, and dried to obtain a single-shell microcapsule powder;

[0064] (6) Disperse 2g of microcapsule powder in 50mL of deionized water and transfer it to a flask. Dissolve 10g of tetraethyl orthosilicate in 10g of anhydrous ethanol to prepare a tetraethyl orthosilicate solution, pour it into the flask containing the microcapsules, stir at 50°C and 500r / min for 30min, add ammonia water to adjust the pH to 6, so that the tetraethyl orthosilicate is hydrolyzed to produce a silica shell, and then further stir for 40min, add 4.46g of tridecafluorooctyltrimethoxysilane and react at 70°C for 4h. Then cool to 40°C and continue the reaction for 12h. After the reaction is completed, the product is washed with deionized water and anhydrous ethanol, filtered, and dried to obtain a new type of rosin derivative modified fluorescent double-shelled isocyanate-based self-healing microcapsules;

[0065] The fluorescent double-shelled isocyanate-based self-healing microcapsules obtained above were modified using the rosin derivatives:

[0066] 20g of polytetrahydrofuran, 14g of isophorone diisocyanate, 2.16g of 2,2-dimethylolpropionic acid, 10g of N,N-dimethylformamide, and 0.08-1% of dibutyltin dilaurate were added to a flask, reacted at 85°C for 2h, and then 0.4g of trimethylolpropane was added to react for 2h. After the reaction was completed, the temperature was lowered to 40°C, 2.4g of triethylamine and 86.56g of ice deionized water were added, and high-speed emulsification was carried out at 2000r / min for 15min to obtain WPU emulsion.

[0067] At room temperature, the prepared WPU emulsion and 3%wt double-shell microcapsules were added to a beaker and stirred at 400r / min. After standing for a period of time, the emulsion was coated on a tinplate patch with a polished surface to obtain a new rosin derivative modified fluorescent double-shell isocyanate-based self-healing microcapsule / polyurethane composite coating.

[0068] Example 2

[0069] The difference between this example and example 1 is that the propylene pimarol in the synthesis of step (1) is replaced by propylene pimaric acid (1-chloro-2-hydroxy) propanediol, and the mass is changed to 11.6 g.

[0070] Example 3

[0071] The difference between this example and Example 1 is that the propylene pinamarin in the synthesis of step (1) is replaced by maleopimarin, and the mass is changed to 7.54 g.

[0072] Comparative Example 1

[0073] The difference between this comparative example and Example 1 is that in the synthesis of step (1), no bio-based rosin derivative is used, only petroleum-based trimethylolpropane is used, and the mass is changed to 5.36 g.

[0074] The tensile strength of the coating was tested with reference to GB / T16777-1997, and the impact resistance of the coating was tested with reference to GB / T1732-2020, as shown in the following table;

[0075]

[0076] The present invention adopts bio-based rosin derivatives as microcapsule core materials, which are green and environmentally friendly. When the coating of the introduced double-shell microcapsules is damaged by external force, the inner core of the isocyanate capsule flows out, and self-repair is achieved by participating in the reaction and curing of water and oxygen in the air without other external conditions. At the same time, due to the presence of the fluorescent agent pre-embedded in the capsule, the self-repairing part uses ultraviolet light to irradiate the coating to generate green fluorescence, so that the damaged area and degree of the coating can be found, so that the coating material has both self-repairing function and self-detection function. By introducing a rigid rosin structure, the mechanical properties of polyurethane are significantly enhanced, and by blending and modifying the double-shell microcapsules with other materials, its application field is further expanded. The joint action of fluorine and silicon elements on the surface of the microcapsules enhances the corrosion resistance of the coating.

[0077] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The specification and examples are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0078] It should be understood that the present invention is not limited to what has been described above and that various modifications and changes may be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for preparing a rosin derivative modified fluorescent double-shell isocyanate-based self-healing microcapsule, characterized in that: include: Step 1: After mixing and stirring a polyol, isophorone diisocyanate and solvent cyclohexanone, a catalyst dibutyltin dilaurate is added thereto to react and prepare an oil phase system; wherein the polyol is one of propylene pimarol, propylene pimaric acid (1-chloro-2-hydroxy) propanediol and maleic pimarol prepared from rosin as a raw material; Step 2: stirring and dispersing the oil phase system, hexamethylene diisocyanate trimer and solvent ethyl acetate to obtain an improved oil phase system; Step 3: stirring and dispersing 4,4-bis(2-disulfonylphenyl)biphenyl and gum arabic in deionized water to obtain an aqueous phase system; Step 4: adding the improved oil phase system dropwise into the water phase system and stirring to obtain an emulsion; Step 5: adding 1,4-butanediol aqueous solution to the emulsion for reaction. After the reaction is completed, the obtained suspension is cooled freely, filtered, washed and dried to obtain single-shell microcapsule powder; Step 6: Disperse the microcapsule powder in deionized water, add the ethanol solution of tetraethyl orthosilicate thereto, stir for reaction, add ammonia water to adjust the pH of the solution to 6, so that the tetraethyl orthosilicate is hydrolyzed to produce a silica shell, and then further stir for 40 minutes, add tridecafluorooctyltrimethoxysilane and react at 70°C for 4 hours; then cool to 40°C and continue to react for 12 hours. After the reaction is completed, the product is washed with deionized water and anhydrous ethanol, filtered, and dried to obtain a novel rosin derivative modified fluorescent double-shelled isocyanate-based self-healing microcapsule.

2. The method for preparing the rosin derivative modified fluorescent double-shell isocyanate-based self-healing microcapsules according to claim 1, characterized in that: The stirring parameters in step 1 are: heating and stirring at 300 r / min and 40° C., and the amount of catalyst added is 0.08%-1% by mass. After adding the catalyst, the reaction temperature is raised to 60° C. and the reaction is carried out for 5 hours to prepare the oil phase system.

3. The method for preparing the rosin derivative modified fluorescent double-shell isocyanate-based self-repairing microcapsules according to claim 1, characterized in that: The reaction temperature in steps 2 and 3 is 25°C.

4. The method for preparing the rosin derivative modified fluorescent double-shell isocyanate-based self-repairing microcapsules according to claim 1, characterized in that: The stirring parameters in step 4 are: stirring at 800 r / min for 15 min.

5. The method for preparing the rosin derivative modified fluorescent double-shell isocyanate-based self-healing microcapsules according to claim 1, characterized in that: The reaction parameters in step 5 are: 70°C, 500r / min, and reaction time of 5h.

6. Application of the rosin derivative modified fluorescent double-shell isocyanate-based self-repairing microcapsules in the field of coatings according to any one of claims 1 to 5, characterized in that: The steps include: Add polytetrahydrofuran, isophorone diisocyanate, 2,2-dihydroxymethylpropionic acid, N,N-dimethylformamide, and 0.08-1% by mass of dibutyltin dilaurate as a catalyst into a flask, react at 85°C for 2h, then add trimethylolpropane to react for 2h, cool to 40°C after the reaction, add triethylamine and ice deionized water, and emulsify at high speed at 2000r / min for 15min to obtain WPU emulsion; At room temperature, WPU emulsion and double-shell isocyanate-based self-healing microcapsules were mixed and stirred at 400 r / min. After standing, the emulsion was coated on a tinplate patch with a polished surface to obtain a new rosin derivative modified fluorescent double-shell isocyanate-based self-healing microcapsule / polyurethane composite coating.

Images