Reflective heat-insulating coating with self-cleaning and self-repairing functions and preparation method thereof

Abstract

The application discloses a reflective heat-insulation coating with self-cleaning and self-repairing properties and a preparation method thereof. The reflective heat-insulation coating is prepared by introducing diamine compounds and dopamine components of different sizes to realize the self-repairing and self-cleaning of the coating. In the application, the reversible covalent activity of the steric ure bond generated by the diamine and dopamine enables the coating to have the self-repairing property. The introduction of nano-polydopamine particles and catechol molecules forms a micro-nano composite structure, significantly strengthens the cohesion and adhesion of the coating, and improves the surface hydrophobic property, so that the surface has a strong self-cleaning ability. The above technical measures can significantly improve the performance of the coating, greatly improve the reflective heat-insulation property and the response ability to adverse environments, and enable the reflective heat-insulation coating to achieve the expected long-term effect, which is of great significance to the realization of long-term temperature control in a complex and adverse environment.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of fine polymer materials, and specifically relates to preparation and construction of a reflective thermal insulation coating with self-cleaning and self-repairing functions and application thereof in the field of temperature control of building structure surfaces. BACKGROUND

[0002] Structure temperature control is one of the key and difficult points faced by modern building structures, and is of great significance to ensuring structure functions, improving the internal comfort of space structures, and reducing the deformation and stress of large-scale infrastructure under external temperature changes. For building structures in exposed environments, solar radiation is an important heat source affecting their temperature changes. In particular, in strong solar radiation areas, the thermal effect caused by solar radiation often becomes the main reason for the temperature fluctuations of structures. Therefore, coating a surface layer of a material with special light-heat properties on the surface of a building structure can enhance the reflection of sunlight and improve the temperature fluctuations of the building structure in a strong solar radiation environment, so as to control the internal temperature of the structure at a lower energy consumption and improve the service life of the infrastructure, which has great application value in the fields of building, transportation, textiles, electrical appliances, military industry and aerospace.

[0003] There are various material forms of high-reflective surface temperature control materials. The initial reflective thermal insulation layer is composed of natural materials, such as natural stone with light color, and metal sheets with high reflectivity, such as aluminum and silver. In addition, there are thin films coated with aluminum and silver, such as aluminum-coated polyester film and aluminum-coated polyimide film. These materials have good reflectivity and have been applied to a certain extent in the fields of aerospace and military industry, but their economic cost is usually high, and the construction requirements are also relatively harsh, thus limiting their application to a certain extent. At present, the high-reflective surface temperature control material most commonly used is reflective thermal insulation coating, which is usually prepared by using an organic film-forming resin as a base material, adding high-reflectivity fillers and pigments, and then solidifying and film-forming on the surface to form a thin layer structure with high reflectivity. Under the background of energy saving and environmental protection, reflective thermal insulation coating has shown potential value and has formed relevant national and industry standards.

[0004] At present, a large number of researchers have studied the preparation of reflective thermal insulation coating. Patent CN117363128A discloses a kind of external wall reflective thermal insulation coating and its preparation method, which uses silicone-acrylate emulsion, rutile titanium dioxide, modified hollow glass microspheres and aerogel powder to prepare a reflective thermal insulation coating with excellent thermal insulation performance and heat reflection ability. Patent CN113637363B discloses a kind of cerium oxide reflective thermal insulation color paste and its preparation method, which uses a single rare earth oxide-cerium oxide as the reflective thermal insulation functional component in the color paste, effectively improving the near-infrared reflectivity of the reflective thermal insulation coating, and the reflective thermal insulation effect is excellent.

[0005] Although the above studies have made certain progress in the preparation of reflective thermal insulation coatings, their performance tests are mainly in the initial stage after preparation. For reflective thermal insulation coatings, their reflective performance is closely related to their surface performance. Since they are used in exposed environments, the surface will inevitably be contaminated by dust or damaged by external forces during long-term use, which has a great impact on the temperature control effect of reflective thermal insulation coatings, resulting in that reflective thermal insulation coatings often fail to achieve the expected use effect in actual use. Therefore, considering the self-cleaning ability after surface contamination and the self-repairing ability after external force damage is the key direction of the development of reflective thermal insulation coatings.

[0006] Some researchers have studied the preparation of coating materials with self-cleaning or self-repairing functions. Patent CN115851071B discloses a preparation method of an environmentally friendly super-hydrophobic anti-biofouling self-repairing coating. The modified carbon nanotube and nano-copper hybrid are loaded with 2-mercaptobenzimidazole and mixed with epoxy resin to obtain a super-hydrophobic self-cleaning coating with a surface micro-nano composite structure, and the coating has anti-biofouling performance and self-repairing performance. Patent CN115851071B discloses a preparation method of a high-transparency super-wear-resistant self-cleaning antibacterial coating. Inorganic nanoparticles, polysiloxane and leveling agents are connected together through chemical bonds, thereby realizing high transparency, super wear resistance and self-cleaning performance of the coating.

[0007] As can be seen from the above description, for reflective thermal insulation coatings, in order to ensure their effect during service, in addition to their durability, their self-cleaning ability against surface contamination and their self-repairing ability against external force damage are also very important. Although there are some related researches at present, the targeted research on the self-cleaning and self-repairing of reflective thermal insulation coatings is still less, and the related products are not mature. Therefore, it is of great significance to carry out related researches to effectively improve the self-cleaning and self-repairing performance of reflective thermal insulation coatings and obtain coating materials with better use performance during actual service, for the technical improvement and popularization and application of the reflective thermal insulation coating industry. SUMMARY

[0008] The purpose of the present application is to solve the above problems and provide a reflective thermal insulation coating with self-cleaning and self-repairing functions, as well as a preparation, construction and application method thereof.

[0009] The reflective heat insulation coating with self-cleaning and self-repairing functions comprises a component A main agent and a component B curing agent, wherein the component A main agent is prepared from fluorocarbon resin, diamine compound, dopamine modified acrylamide, polydopamine particles, filler, solvent, functional additive, color paste and rheological modifier, wherein the diamine compound is at least one of ethylenediamine, propylenediamine, butylenediamine, pentanediamine, hexanediamine, p-phenylenediamine, p-xylylenediamine, diaminobiphenyl and diaminonaphthalene; the polydopamine particles are polymer particles formed by precipitation polymerization of dopamine, and the particle size is 50-200 nm; the component B curing agent is prepared by mixing isocyanate and solvent; and the mass ratio of the component A main agent to the component B curing agent is 1:(0.08-0.22).

[0010] The dopamine modified acrylamide in the reflective heat insulation coating is at least one of dopamine methacrylamide, dopamine acrylamide, dopa methacrylamide and dopa acrylamide; and the molar mass ratio of the diamine compound to the dopamine modified acrylamide is 1:(1.9-2.1).

[0011] In the component A main agent of the reflective heat insulation coating, the content of the fluorocarbon resin, the diamine compound, the dopamine modified acrylamide, the polydopamine particles, the filler, the solvent, the functional additive, the color paste and the rheological modifier is 50-65%, 0.5-1%, 1-5%, 3-6%, 15-25%, 3-10%, 0.5-3.5%, 0.1-2% and 0.5-1.5% respectively based on the total mass of the component A; the fluorocarbon resin is at least one of water-based or solvent-based polyvinylidene fluoride resin, polytrifluorochloroethylene-vinyl ether resin and polytrifluorochloroethylene-vinyl ether resin; the filler is at least one of rutile titanium dioxide, potassium hexatitanate whisker, ceramic hollow microbead, hollow glass microbead and far-infrared ceramic powder; the solvent is at least one of dimethylbenzene, acetone, butyl acetate, dimethylformamide, cyclic ether, propylene glycol methyl ether acetate and water; the functional additive is at least one of dispersant, defoaming agent, leveling agent, adhesion promoter and antioxidant; the color paste is at least one of black color paste of Clariant, DeGussa, Hips, BASF and Shinan; and the rheological modifier is at least one of bentonite, hydrated magnesium silicate, fumed silica and polymer wax.

[0012] The content of isocyanate and solvent in the curing agent of the B component of the reflective thermal insulation coating is 85%-100% and 0-15%, based on the total mass of the B component; wherein the isocyanate is at least one of toluene diisocyanate, isophorone diisocyanate, diphenyl methane diisocyanate, dicyclohexyl methane diisocyanate, hexamethylene diisocyanate, cyclohexane dimethylene diisocyanate, p-phenylene diisocyanate, toluene diisocyanate trimer, hexamethylene diisocyanate trimer, and hexamethylene diisocyanate biuret; and the solvent is at least one of xylene, acetone, butyl acetate, dimethylformamide, cyclic ether, propylene glycol methyl ether acetate, and water.

[0013] The preparation method of the reflective thermal insulation coating comprises the following steps:

[0014] (1) Preparation of polydopamine particles: water, ethanol and ammonia water are prepared into a reaction solution, hydrochloric acid dopamine and polyethylene glycol 2000 are added into the reaction solution, the reaction solution is heated to 65℃ under mechanical stirring for 16h after complete dissolution, and the reaction solution is centrifuged at high speed after the reaction is completed, the precipitate is taken out, washed with deionized water, and dried in a vacuum oven for 24h to obtain polydopamine particles;

[0015] (2) Preparation of A component main agent: appropriate amounts of components are weighed, diamine compounds and dopamine modified acrylamide are added into fluorocarbon resin, and mechanical stirring is carried out at 40-60℃ for 3h, after the reaction, fillers and polydopamine particles are added into the fluorocarbon resin, the mixture is dispersed and mixed at room temperature using a high-speed dispersing machine at a linear speed of 3-5m / s for 20min, and treated using an ultrasonic dispersing machine for 4-10min to obtain Aa mixture; solvents, functional additives, color paste and rheological modifiers are mixed at room temperature, pre-dispersed using a high-speed dispersing machine at low speed for 5min, and after standing for 10min, high-speed dispersion is carried out at a linear speed of 18-24m / s for 10min to obtain Ab mixture; the Ab mixture is dispersed at a linear speed of 6-10m / s for 5-10min to obtain the A component main agent.

[0016] (3) Preparation of B component curing agent: isocyanate and solvent are dispersed and mixed using a high-speed dispersing machine for 10-15min to obtain the B component curing agent;

[0017] The reaction solution in the preparation method of the reflective thermal insulation coating is composed of 60% water, 38% alcohol solvent and 2% ammonia water; wherein the alcohol solvent is at least one of methanol, ethanol and isopropanol, the reaction concentration of dopamine hydrochloride is 0.5-1.5%, and the reaction concentration of polyethylene glycol 2000 is 0.05-0.2%.

[0018] The dry film thickness of the dust suppression and sealing coating of the reflective thermal insulation coating after construction is 120-200 mu m, and the construction method can be any one of spraying, dipping, rolling and brushing

[0019] The positive effect of the reflective thermal insulation coating with self-cleaning and self-repairing functions in the application is:

[0020] The reflective thermal insulation coating with self-cleaning and self-repairing functions prepared in the application is composed of A component main agent containing diamine compound and multi-size dopamine component and B component curing agent. In the application, the self-repairing and self-cleaning of the reflective thermal insulation coating are realized by introducing three functional components of diamine compound, polydopamine particles and dopamine modified acrylamide. In the preparation process of the A component, the diamine will undergo Michael addition with the dopamine modified acrylamide to generate a binary secondary amine with a large steric side chain with two o-diphenol structures. When the secondary amine reacts and cures with the isocyanate in the B component, a urea bond with a large steric group is generated. Because the large steric group prevents the lone pair of electrons of nitrogen in the urea bond from delocalizing into the C=O bond, the large steric urea bond exhibits the characteristics of reversible reaction. At room temperature, it can be used as a urea bond to strengthen the mechanical properties and optical properties of the system. At 40-50 DEG C which is slightly higher than room temperature (usually under direct sunlight outdoors), the reversible reaction occurs, and the coating can be self-repaired after being damaged by external force as a reversible covalent bond.

[0021] The nanoscale polydopamine particles can interact with the micrometer-sized fillers and dopamine-modified small molecule monomers during the drying process, and form a micro-nano composite structure on the surface through volume lapping, chemical reaction and hydrogen bonding. On the one hand, it significantly improves the surface roughness and hydrophobicity, making the surface have strong self-cleaning ability. On the other hand, it also significantly enhances the bonding force between the coating system and the substrate, and the mechanical, durability and long-term adhesion properties of the overall coating in the exposed environment are also significantly improved. The working performance and ability to cope with adverse environments of the reflective thermal insulation coating are greatly improved, so that the reflective thermal insulation coating can truly achieve the expected long-term effect.

[0022] From the above description, it can be seen that the mechanism of the technology is clear, the production process is simple, the performance is excellent, and it is suitable for large-scale production. It has important significance for the long-term and durable temperature control of houses, factories, large infrastructure in outdoor exposed environment, especially in harsh and complex environment. DETAILED DESCRIPTION

[0023] The application will be further described in detail below in combination with specific examples.

[0024] Example 1: A reflective thermal insulation coating with self-cleaning and self-repairing functions, the preparation process of A1 component main agent and B1 component curing agent is as follows:

[0025] (1) 60 parts of water, 38 parts of ethanol and 2 parts of ammonia water are configured as a reaction solution, 1 part of dopamine hydrochloride and 0.1 part of polyethylene glycol 2000 are added to the reaction solution, after complete dissolution, the reaction solution is heated to 65°C under mechanical stirring for 16h, after the reaction is completed, the reaction solution is centrifuged at high speed, after centrifugation, the precipitate is taken out, washed with deionized water and dried in a vacuum oven for 24h to obtain polydopamine particles.

[0026] (2) 1 part of pentanediamine and 4.1 parts of dopamine methacrylamide are weighed and added to 58 parts of solvent-based polytrifluorochloroethylene-vinyl ether resin, and the mixture is mechanically stirred at 50°C for 3h, after the reaction, 22 parts of rutile titanium dioxide and 3.5 parts of polydopamine particles are added, and the mixture is dispersed and mixed at room temperature at a linear speed of 4m / s for 20min, and treated with an ultrasonic dispersing machine for 6min to obtain Aa1 mixture; 8 parts of xylene, 0.4 parts of dispersing agent, 0.4 parts of leveling agent, 0.5 parts of defoaming agent, 1.2 parts of Clariant RLSN 01 and 0.9 parts of hydrated magnesium silicate are mixed at room temperature and pre-dispersed at low speed for 5min using a high-speed dispersing machine, the pre-dispersed mixture is left for 10min, and then high-speed dispersed at a linear speed of 20m / s for 10min to obtain Ab1 mixture; the Ab1 mixture is added to the Aa1 mixture under the dispersion condition of a linear speed of 8m / s for 6min until the system is uniform and stable to obtain A1 component main agent.

[0027] (3) 60 parts of toluene diisocyanate, 35 parts of toluene diisocyanate trimer and 5 parts of xylene are weighed and dispersed and mixed using a high-speed dispersing machine for 15min until the system is uniform and stable to obtain B1 component curing agent.

[0028] The mass ratio of A1 main agent to B1 curing agent of the reflective thermal insulation coating during use is 1:0.13, and after uniform mixing using mechanical stirring, the construction can be carried out.

[0029] Example 2: A reflective thermal insulation coating with self-cleaning and self-repairing functions, the preparation process of A2 component main agent and B2 component curing agent is as follows:

[0030] (1) The preparation process of polydopamine particles is the same as that of Example 1.

[0031] (2) Take 0.8 parts of hexanediamine and 3.5 parts of dopa methyl acrylamide into 61 parts of water-based polyvinylidene fluoride resin, mechanically stir at 50°C for 3h, then add 20 parts of potassium titanate whisker and 4.2 parts of polydopamine particles into the mixture, disperse the mixture at room temperature with a high-speed disperser at a linear speed of 4m / s for 20min, and then treat it with an ultrasonic disperser for 6min to obtain Aa2 mixture; mix 7.4 parts of water, 0.5 parts of dispersant, 0.5 parts of antioxidant, 1.5 parts of BASF L0080 and 0.6 parts of fumed silica at room temperature, and pre-disperse the mixture at low speed with a high-speed disperser for 5min, then stand for 10min, and then disperse at a high speed of 20m / s for 10min to obtain Ab2 mixture; add the Ab2 mixture into the Aa2 mixture at a linear speed of 8m / s for 6min until the system is uniform and stable to obtain A2 component main agent.

[0032] (3) Use hydrophilic HDI polyisocyanate as B2 component curing agent.

[0033] The mass ratio of A2 main agent and B2 curing agent in the reflective thermal insulation coating during use is 1:0.15, and the mixture can be uniformly mixed by mechanical stirring, and then construction can be carried out.

[0034] Example 3: A reflective thermal insulation coating with self-cleaning and self-repairing functions, the preparation process of A3 component main agent and B3 component curing agent is as follows:

[0035] (1) The preparation process of polydopamine particles is the same as that of Example 1.

[0036] (2) Take 0.6 parts of p-phenylenediamine and 2.4 parts of dopa acrylamide into 53 parts of solvent-based polytetrafluoroethylene-vinyl ether resin, mechanically stir at 50°C for 3h, then add 24 parts of rutile titanium dioxide and 5.5 parts of polydopamine particles into the mixture, disperse the mixture at room temperature with a high-speed disperser at a linear speed of 4m / s for 20min, and then treat it with an ultrasonic disperser for 6min to obtain Aa3 mixture; mix 8.7 parts of acetone, 1 part of dispersant, 1 part of defoaming agent, 1 part of leveling agent, 1.6 parts of Clariant RLSN 01 and 1.2 parts of bentonite at room temperature, and pre-disperse the mixture at low speed with a high-speed disperser for 5min, then stand for 10min, and then disperse at a high speed of 20m / s for 10min to obtain Ab3 mixture; add the Ab3 mixture into the Aa3 mixture at a linear speed of 8m / s for 6min until the system is uniform and stable to obtain A3 component main agent.

[0037] (3) Take 50 parts of isophorone diisocyanate, 35 parts of polymethylene polyphenyl polyisocyanate and 15 parts of acetone, and use a high-speed dispersing machine to disperse and mix for 15 min until the system is uniform and stable to obtain the B3 component curing agent.

[0038] The mass ratio of A3 main agent to B3 curing agent in the reflective thermal insulation coating during use is 1:0.12, and after uniform mixing using mechanical stirring, construction can be performed.

[0039] Example 4: A reflective thermal insulation coating with self-cleaning and self-repairing functions, the preparation process of A4 component main agent and B4 component curing agent is as follows:

[0040] (1) The preparation process of polydopamine particles is the same as that of Example 1.

[0041] (2) Take 0.8 parts of butanediamine and 3.8 parts of dopamine acrylamide and add them to 58 parts of water-based polytrifluorochloroethylene-vinyl ether resin, and mechanically stir at 50°C for 3h. After the reaction, 23 parts of ceramic hollow microbeads and 4.5 parts of polydopamine particles are added, and the mixture is dispersed and mixed using a high-speed dispersing machine at room temperature at a linear speed of 4m / s for 20min, and treated using an ultrasonic dispersing machine for 6min to obtain Aa4 mixture; mix 6.3 parts of water, 0.6 parts of dispersant, 0.6 parts of leveling agent, 0.6 parts of mildewcide, 0.8 parts of DeForest C8 and 1 part of polyamide wax at room temperature and pre-disperse using a high-speed dispersing machine at low speed for 5min, and then stand for 10min, and then disperse at a linear speed of 18-24m / s for 10min to obtain Ab4 mixture; add the Ab4 mixture to the Aa4 mixture under the dispersion condition of a linear speed of 8m / s for 6min until the system is uniform and stable to obtain the A4 component main agent.

[0042] (3) Use hydrophilic HDI polyisocyanate as the B4 component curing agent.

[0043] The mass ratio of A4 main agent to B4 curing agent in the reflective thermal insulation coating during use is 1:0.16, and after uniform mixing using mechanical stirring, construction can be performed.

[0044] Example 5: A reflective thermal insulation coating with self-cleaning and self-repairing functions, the preparation process of A5 component main agent and B5 component curing agent is as follows:

[0045] (1) The preparation process of polydopamine particles is the same as that of Example 1.

[0046] (2) Take 0.6 parts of diaminobiphenyl and 1.3 parts of dopa propylamide into 62 parts of solvent polyvinylidene fluoride resin, mechanically stir the reaction at 50℃ for 3h, after the reaction, add 12 parts of rutile titanium dioxide, 6 parts of hollow glass microspheres and 5 parts of polydopamine particles into it, disperse the mixture at room temperature with a high-speed disperser at a linear speed of 4m / s for 20min, and then treat it with an ultrasonic disperser for 6min to obtain Aa5 mixture; mix 9.4 parts of butyl acetate, 0.5 parts of leveling agent, 0.5 parts of defoaming agent, 2 parts of Shenming SM8809 and 0.75 parts of fumed silica at room temperature, and pre-disperse the mixture with a high-speed disperser at low speed for 5min, stand for 10min, and then disperse it at a linear speed of 20m / s for 10min to obtain Ab5 mixture; disperse Ab5 mixture into Aa5 mixture at a linear speed of 8m / s for 6min until the system is uniform and stable to obtain A5 component main agent.

[0047] (3) Take 60 parts of dicyclohexyl methane diisocyanate, 35 parts of hexamethylene diisocyanate biuret and 5 parts of butyl acetate, and disperse and mix them with a high-speed disperser for 15min until the system is uniform and stable to obtain B5 component curing agent.

[0048] The mass ratio of A5 main agent and B5 curing agent of the reflective thermal insulation coating during use is 1:0.14, and after mixing uniformly with mechanical stirring, it can be applied.

[0049] Example 6: A reflective thermal insulation coating with self-cleaning and self-repairing functions, the preparation process of A6 component main agent and B6 component curing agent is as follows:

[0050] (1) The preparation process of polydopamine particles is the same as that of Example 1.

[0051] (2) Take 0.8 parts of hexanediamine and 3.7 parts of dopa methyl acrylamide into 54 parts of solvent-based polytrifluorochloroethylene-vinyl ether resin, mechanically stir and react at 50°C for 3h, then add 16 parts of rutile titanium dioxide, 8 parts of ceramic hollow microbeads and 3.8 parts of polydopamine particles into it, disperse and mix the mixture at room temperature with a high-speed disperser at a linear speed of 4m / s for 20min, and then treat it with an ultrasonic disperser for 6min to obtain Aa6 mixture; mix 8.3 parts of propylene glycol methyl ether acetate, 1 part of leveling agent, 1 part of defoaming agent, 0.8 parts of mildewcide, 1.2 parts of HIBIS CH2 and 1.35 parts of fumed silica at room temperature, and pre-disperse the mixture with a high-speed disperser at low speed for 5min, then stand for 10min, and then disperse at a high speed of 20m / s for 10min to obtain Ab6 mixture; disperse the Ab6 mixture into the Aa6 mixture at a linear speed of 8m / s for 6min until the system is uniform and stable to obtain A6 component main agent.

[0052] (3) Take 93 parts of cyclohexane dimethylene diisocyanate and 7 parts of propylene glycol methyl ether acetate, and disperse and mix the mixture with a high-speed disperser for 15min until the system is uniform and stable to obtain B6 component curing agent.

[0053] The mass ratio of A6 main agent and B6 curing agent of the reflective thermal insulation coating during use is 1:0.09, and the mixture can be uniformly mixed by mechanical stirring before construction.

[0054] Example 7: A reflective thermal insulation coating with self-cleaning and self-repairing functions, the preparation process of A7 component main agent and B7 component curing agent is as follows:

[0055] (1) The preparation process of polydopamine particles is the same as that of Example 1.

[0056] (2) Take 0.6 parts of p-phenylenediamine and 2.3 parts of dopamine acrylamide into 60 parts of water-based polytetrafluorochloroethylene-vinyl ether resin, mechanically stir and react at 50°C for 3h, then add 10 parts of potassium hexatitanate whiskers, 10 parts of far infrared ceramic powder and 5.8 parts of polydopamine particles into it, disperse and mix the mixture at room temperature with a high-speed disperser at a linear speed of 4m / s for 20min, and then treat it with an ultrasonic disperser for 6min to obtain Aa7 mixture; mix 7.8 parts of water, 1 part of defoaming agent, 0.3 parts of ultraviolet absorber, 1.6 parts of BASF L0080 and 0.55 parts of polyethylene wax at room temperature, and pre-disperse the mixture with a high-speed disperser at low speed for 5min, then stand for 10min, and then disperse at a high speed of 20m / s for 10min to obtain Ab7 mixture; disperse the Ab7 mixture into the Aa7 mixture at a linear speed of 8m / s for 6min until the system is uniform and stable to obtain A7 component main agent.

[0057] (3) Using hydrophilic modified IPDI polyisocyanate as B7 curing agent.

[0058] The mass ratio of A7 resin and B7 curing agent in the reflective thermal insulation coating during use is 1:0.2, and after uniform mixing by mechanical stirring, construction can be carried out.

[0059] Example 8: A reflective thermal insulation coating with self-cleaning and self-repairing functions, the preparation process of A8 component main agent and B8 component curing agent is as follows:

[0060] (1) The preparation process of polydopamine particles is the same as that of Example 1.

[0061] (2) 0.8 parts of propylene diamine and 4.7 parts of dopamine methacrylamide are weighed and added to 63 parts of solvent-based polyvinylidene fluoride resin, and mechanical stirring is carried out at 50°C for 3h. After reaction, 13 parts of rutile titanium dioxide, 6 parts of hollow glass microbeads and 3.6 parts of polydopamine particles are added, and the mixture is dispersed and mixed at room temperature using a high-speed dispersing machine at a linear speed of 4m / s for 20min, and treated using an ultrasonic dispersing machine for 6min to obtain Aa8 mixture; 3.9 parts of dimethylformamide, 1.2 parts of dispersant, 1.2 parts of leveling agent, 1.5 parts of BASF L0080 and 1.2 parts of fumed silica are mixed at room temperature and pre-dispersed using a high-speed dispersing machine at low speed for 5min. After standing for 10min, the pre-dispersed mixture is high-speed dispersed at a linear speed of 20m / s for 10min to obtain Ab8 mixture; Ab8 mixture is added to Aa8 mixture under the dispersion condition of a linear speed of 8m / s for 6min until the system is uniform and stable to obtain A8 component main agent.

[0062] (3) 60 parts of isophorone diisocyanate, 30 parts of hexamethylene diisocyanate trimer and 10 parts of dimethylformamide are weighed and dispersed and mixed using a high-speed dispersing machine for 15min until the system is uniform and stable to obtain B8 component curing agent.

[0063] The mass ratio of A8 main agent and B8 curing agent in the reflective thermal insulation coating during use is 1:0.13, and after uniform mixing by mechanical stirring, construction can be carried out.

[0064] Comparative Example 1: Commercial reflective thermal insulation coating

[0065] A certain brand of protective coating on the market is taken for performance comparison.

[0066] Comparative Example 2: A conventional reflective thermal insulation coating, the preparation process of A9 component main agent and B9 component curing agent is as follows:

[0067] (1) Take 60 parts of water-based polytetrafluoroethylene-vinyl ether resin, 10 parts of rutile titanium dioxide and 10 parts of far infrared ceramic powder, and use a high-speed dispersing machine to disperse and mix at room temperature at a linear speed of 4 m / s for 20 min, and use an ultrasonic dispersing machine to treat for 6 min to obtain Aa9 mixture; mix 16.6 parts of water, 1 part of defoaming agent, 0.3 parts of ultraviolet absorber, 1.6 parts of BASF L0080 and 0.55 parts of polyethylene wax at room temperature and use a high-speed dispersing machine to pre-disperse at low speed for 5 min, and then use a high-speed dispersing machine to disperse at a linear speed of 20 m / s for 10 min after the pre-dispersed mixture is left for 10 min to obtain Ab9 mixture; add the Ab9 mixture to the Aa9 mixture under the dispersion condition of a linear speed of 8 m / s for 6 min until the system is uniform and stable to obtain A9 component main agent.

[0068] (2) Use hydrophilic modified IPDI polyisocyanate as B9 component curing agent.

[0069] The mass ratio of A9 main agent and B9 curing agent of the coating during the test is 1:0.2.

[0070] Comparative Example 3: A reflective thermal insulation coating only adding polydopamine microspheres, the preparation process of A10 component main agent and B10 component curing agent is as follows:

[0071] (1) The preparation process of polydopamine particles is the same as that of Example 1.

[0072] (2) Take 54 parts of solvent-based polytrifluoroethylene-vinyl ether resin, 16 parts of rutile titanium dioxide, 8 parts of ceramic hollow microbeads and 3.8 parts of polydopamine particles, mix them, and use a high-speed dispersing machine to disperse and mix at room temperature at a linear speed of 4 m / s for 20 min, and use an ultrasonic dispersing machine to treat for 6 min to obtain Aa10 mixture; mix 12.9 parts of propylene glycol methyl ether acetate, 1 part of leveling agent, 1 part of defoaming agent, 0.8 parts of mildewcide, 1.2 parts of HIBIS CH2 and 1.35 parts of fumed silica at room temperature and use a high-speed dispersing machine to pre-disperse at low speed for 5 min, and then use a high-speed dispersing machine to disperse at a linear speed of 20 m / s for 10 min after the pre-dispersed mixture is left for 10 min to obtain Ab10 mixture; add the Ab10 mixture to the Aa10 mixture under the dispersion condition of a linear speed of 8 m / s for 6 min until the system is uniform and stable to obtain A10 component main agent.

[0073] (3) Take 93 parts of cyclohexane dimethylene diisocyanate and 7 parts of propylene glycol methyl ether acetate, and use a high-speed dispersing machine to disperse and mix for 15 min until the system is uniform and stable to obtain B10 component curing agent.

[0074] The mass ratio of A10 main agent and B10 curing agent of the coating during the test is 1:0.09.

[0075] Comparative Example 4: Preparation of a reflective thermal insulation coating using only dopa-modified acrylamide, A11 component main agent and B11 component curing agent, as follows:

[0076] (1) 3.7 parts of dopa methacrylamide were weighed into 54 parts of solvent-based polytrifluorochloroethylene-vinyl ether resin, and mechanically stirred at 50°C for 3h. After the reaction, 16 parts of rutile titanium dioxide and 8 parts of ceramic hollow microbeads were added, and the mixture was dispersed and mixed at room temperature using a high-speed disperser at a linear speed of 4m / s for 20min, and treated using an ultrasonic disperser for 6min to obtain Aa11 mixture. 13 parts of propylene glycol methyl ether acetate, 1 part of leveling agent, 1 part of defoaming agent, 0.8 parts of mildewcide, 1.2 parts of HIBIS CH2, and 1.35 parts of fumed silica were mixed at room temperature and pre-dispersed using a high-speed disperser at low speed for 5min. The pre-dispersed mixture was left to stand for 10min, and then high-speed dispersed at a linear speed of 20m / s for 10min to obtain Ab11 mixture. The Ab11 mixture was added to the Aa11 mixture under dispersion conditions at a linear speed of 8m / s for 6min until the system was uniform and stable to obtain the A11 component main agent.

[0077] (2) 93 parts of cyclohexane dimethylene diisocyanate and 7 parts of propylene glycol methyl ether acetate were dispersed and mixed using a high-speed disperser for 15min until the system was uniform and stable to obtain the B11 component curing agent.

[0078] The mass ratio of the A11 main agent and the B11 curing agent in the coating during the test was 1:0.09.

[0079] Comparative Example 5: Preparation of a reflective thermal insulation coating using only a diamine compound, A12 component main agent and B12 component curing agent, as follows:

[0080] (1) 0.8 parts of hexamethylene diamine were weighed into 54 parts of solvent-based polytrifluorochloroethylene-vinyl ether resin, and mechanically stirred at 50°C for 3h. After the reaction, 16 parts of rutile titanium dioxide and 8 parts of ceramic hollow microbeads were added, and the mixture was dispersed and mixed at room temperature using a high-speed disperser at a linear speed of 4m / s for 20min, and treated using an ultrasonic disperser for 6min to obtain Aa12 mixture. 15.8 parts of propylene glycol methyl ether acetate, 1 part of leveling agent, 1 part of defoaming agent, 0.8 parts of mildewcide, 1.2 parts of HIBIS CH2, and 1.35 parts of fumed silica were mixed at room temperature and pre-dispersed using a high-speed disperser at low speed for 5min. The pre-dispersed mixture was left to stand for 10min, and then high-speed dispersed at a linear speed of 20m / s for 10min to obtain Ab12 mixture. The Ab12 mixture was added to the Aa12 mixture under dispersion conditions at a linear speed of 8m / s for 6min until the system was uniform and stable to obtain the A12 component main agent.

[0081] (2) Take 93 parts of cyclohexane dimethylene diisocyanate and 7 parts of propylene glycol methyl ether acetate, and use a high-speed disperser to disperse and mix for 15 min until the system is uniform and stable to obtain a B12 component curing agent.

[0082] The mass ratio of the A12 main agent to the B11 curing agent of the coating during the test is 1:0.09.

[0083] Comparative Example 6: A reflective thermal insulation coating using large-size polydopamine microspheres, the preparation process of the A13 component main agent and the B13 component curing agent is as follows:

[0084] (1) 60 parts of water, 38 parts of ethanol and 2 parts of ammonia water are configured into a reaction solution, 5 parts of dopamine hydrochloride and 0.5 parts of polyethylene glycol 2000 are added into the reaction solution, after complete dissolution, the reaction solution is heated to 65°C under mechanical stirring for 36 h, after the reaction is completed, the reaction solution is centrifuged at high speed, after centrifugation, the precipitate is taken out, washed with deionized water and dried in a vacuum oven for 24 h to obtain large-size polydopamine particles.

[0085] (2) Take 0.8 parts of butanediamine and 3.8 parts of dopamine acrylamide and add them into 58 parts of water-based polytrifluorochloroethylene-vinyl ether resin, mechanically stir at 50°C for 3 h, after the reaction, add 23 parts of ceramic hollow microbeads and 4.5 parts of large-size polydopamine particles into it, use a high-speed disperser to disperse and mix the mixture at room temperature at a linear speed of 4 m / s for 20 min, use an ultrasonic disperser to treat for 6 min to obtain an Aa13 mixture; mix 6.3 parts of water, 0.6 parts of dispersant, 0.6 parts of leveling agent, 0.6 parts of mildewcide, 0.8 parts of DeGussa C8 and 1 part of polyamide wax at room temperature and pre-disperse the mixture using a high-speed disperser at low speed for 5 min, let the pre-dispersed mixture stand for 10 min, then high-speed disperse at a linear speed of 18-24 m / s for 10 min to obtain an Ab13 mixture; add the Ab13 mixture into the Aa13 mixture under a dispersing condition of a linear speed of 8 m / s for 6 min until the system is uniform and stable to obtain an A13 component main agent.

[0086] (3) Use hydrophilic HDI polyisocyanate as a B13 component curing agent.

[0087] The mass ratio of the A13 main agent to the B13 curing agent of the coating during the test is 1:0.16.

[0088] Comparative Example 7: A reflective thermal insulation coating prepared using a conventional steric amine and dopamine microspheres, the preparation process of the A14 component main agent and the B14 component curing agent is as follows:

[0089] (1) The preparation process of the polydopamine particles is the same as that of Example 1.

[0090] (2) Take 0.8 parts of N,N-bis(tert-butyl) vinyl diamine into 63 parts of solvent type polyvinylidene fluoride resin, mechanically stir the reaction at 50°C for 3h, after the reaction, add 13 parts of rutile titanium dioxide, 6 parts of hollow glass microbeads and 3.6 parts of polydopamine particles into it, disperse and mix the mixture at room temperature using a high-speed dispersing machine at a linear speed of 4m / s for 20min, and then treat it using an ultrasonic dispersing machine for 6min to obtain the Aa14 mixture; mix 8.6 parts of dimethylformamide, 1.2 parts of dispersant, 1.2 parts of leveling agent, 1.5 parts of BASF L0080 and 1.2 parts of fumed silica at room temperature, and pre-disperse the mixture using a high-speed dispersing machine at low speed for 5min, then stand for 10min, and then disperse at a linear speed of 20m / s for 10min to obtain the Ab14 mixture; disperse the Ab14 mixture into the Aa14 mixture at a linear speed of 8m / s for 6min until the system is uniform and stable to obtain the A14 component main agent.

[0091] (3) Take 60 parts of isophorone diisocyanate, 30 parts of hexamethylene diisocyanate trimer and 10 parts of dimethylformamide, and disperse and mix the mixture using a high-speed dispersing machine for 15min until the system is uniform and stable to obtain the B14 component curing agent.

[0092] The mass ratio of the A14 main agent and the B14 curing agent of the coating during the test is 1:0.13.

[0093] Effect description:

[0094] The reflective heat-insulating coating with self-cleaning and self-repairing functions prepared in Examples 1-8 in the application was used to prepare samples, and the performance tests were compared with Comparative Examples 1-9. Among them, Comparative Examples 1-7 are the coating samples prepared by Comparative Examples 1-7 above, and Comparative Examples 8-9 are coating samples prepared by using Example 6, and the thicknesses are 400μm and 60μm respectively. The thicknesses of the remaining samples are in the range of 120-200μm except Comparative Examples 8-9.

[0095] The test films of the coating prepared using the corresponding coating are subjected to performance tests such as tensile strength, adhesion strength, photothermal performance, water contact angle, change rate of solar reflectance after dirt washing (self-cleaning performance), scratch recovery time (self-repairing performance), and the like. The tensile strength is tested according to GB / T 528-2009; the adhesion strength is tested according to GB / T5210-2006; the lightness value is tested according to GB / T 11186.2-1989; the solar reflectance and hemispherical emissivity are tested according to JG / T 235-2014; the water contact angle is tested using a contact angle measuring instrument; the change rate of solar reflectance after dirt washing (self-cleaning performance) is tested after the test film is contaminated with standard dirt and then washed with 1.5 kg of water at a height of 1.5 m; and the scratch recovery time is the time for the test film to be placed at 45°C until the scratch disappears after being scratched with a blade.

[0096] The relevant test results are arranged in Table 1:

[0097] Table 1 Performance test results of the reflective thermal insulation coating

[0098] Sample Tensile strength / MPa Adhesion strength / MPa L* value Solar reflectance Hemispherical emittance Water contact angle / ° Solar reflectance recovery / % Scratch recovery time / h Example 1 15.8 6.9 72 0.61 0.91 155 96 0.8 Example 2 14.7 5.5 71 0.60 0.90 158 97 1.3 Example 3 14.5 6.3 72 0.60 0.92 156 96 1.6 Example 4 13.9 5.8 73 0.62 0.89 158 98 1.2 Example 5 15.1 7.4 72 0.60 0.90 160 95 1.3 Example 6 14.3 5.8 73 0.61 0.91 156 99 1.8 Example 7 15.8 6.0 71 0.59 0.90 154 96 1 Example 8 13.6 6.6 72 0.60 0.92 155 98 1.4 Comparative Example 1 10.1 3.2 75 0.58 0.80 85 62 / Comparative Example 2 12.5 4.3 71 0.58 0.86 95 75 / Comparative Example 3 11.8 4.8 73 0.59 0.88 110 78 / Comparative Example 4 12.8 4.5 73 0.58 0.86 92 74 / Comparative Example 5 13.1 4.0 73 0.58 0.85 90 72 / Comparative Example 6 9.5 3.8 73 0.60 0.86 120 81 1.5 Comparative Example 7 13.6 5.0 72 0.59 0.88 106 76 4 Comparative Example 8 14.5 5.5 73 0.61 0.87 125 83 2.5 Comparative Example 9 14.3 5.7 73 0.58 0.88 110 75 2

[0099] As can be seen from the data in Table 1, the reflective thermal insulation coating prepared in the examples is excellent in mechanical properties, adhesion properties, photothermal performance, and the like, because the dopamine groups contained therein can better improve the adhesion of the fillers and the resin in the matrix and the interaction with the adhesion matrix. And due to the addition of polydopamine microspheres, the formation of the surface micro-nano structure improves the solar reflectance performance and infrared radiation ability, and more obviously, due to the introduction of diamine, dopamine-modified acrylamide and polydopamine microspheres, the coating has super-hydrophobic self-cleaning performance, and after being contaminated with dust, a simple rinse can restore the surface photothermal performance, and the damage to the related coating can be completely recovered at 45°C for 1-2 h, which is of great significance for the long-term durability of the reflective thermal insulation coating in harsh exposure environments.

[0100] The performance of Comparative Examples 1-9 compared with the examples can be seen that the overall performance gap is relatively obvious, and the difference in radiation performance, self-cleaning performance and self-repairing performance is more obvious. This is mainly caused by the close combination degree of the fillers and the matrix, the lack of dynamic covalent bonds and the lack of surface micro-nano structure. The following is a specific analysis.

[0101] Comparative Example 1 is a commercially available reflective thermal insulation coating, and it can be seen that its performance is greatly different from that of the examples, mainly because the commercially available conventional product is not specifically optimized, and the quality and amount of the resin, filler and other materials are poor, so the performance cannot meet the use requirements. In Comparative Example 2, only conventional fillers and resins are used, and the performance effect is greatly different from that of the examples, and it does not have self-cleaning and self-repairing capabilities, and the performance decreases significantly during long-term application. Comparative Example 3, Comparative Example 4 and Comparative Example 5 respectively use polydopamine microspheres, dopamine-modified acrylamide and diamines, but the overall performance is not obviously improved compared with the conventional reflective thermal insulation, firstly because all of them are binary tertiary amine molecules with large steric hindrance, so they cannot form reversible steric urea bonds during the reaction process, and therefore they all do not have self-repairing performance, in addition, Comparative Examples 4 and 5 cannot form micro-nano structures, and Comparative Example 3 contains nano microspheres, but lacks free catechol groups as coupling agents, so the formation of micro-nano structures is not tight, and the binding force is weak, so all of them are insufficient in hydrophobic self-cleaning, and therefore cannot meet the related performance requirements.

[0102] In Comparative Example 6, polydopamine microspheres with a large diameter are used as an additive component, although they can form a combination between different fillers, but they are not micro-nano structures, so their hydrophobic self-cleaning performance is weak. In Comparative Example 7, a common binary steric amine is used, although it has a certain self-repairing capability, but because its reversibility is weak, the repair time is significantly prolonged compared with the examples, and because there is no free catechol group, the formation of micro-nano structures is weak, so the performance of hydrophobic self-cleaning is also insufficient, so it can be seen that the ternary addition designed in the present application can play a significant synergistic enhancement effect, and at the same time realize the self-repairing and self-cleaning of the coating. In Comparative Example 8, the thickness of the coating is relatively thick, so the self-assembly micro-nano structure process of the coating during the drying process is weak, and therefore the performance decreases significantly. In Comparative Example 9, the thickness of the coating is relatively thin, on the one hand the micro-nano structure is not completely formed, and on the other hand the hiding power also decreases, so its performance is also insufficient, and the overall performance is significantly different from that of the examples.

[0103] The above is only a preferred embodiment of the present application, and does not limit the present application in any form, and any simple modification, equivalent change and modification of the above examples based on the technical essence of the present application, all still belong to the scope of the technical solution of the present application.

Claims

1. A reflective heat-insulating coating with self-cleaning and self-repairing functions, characterized in that: The product consists of component A (main agent) and component B (curing agent). Component A (main agent) is prepared from fluorocarbon resin, diamine compounds, dopamine-modified acrylamide, polydopamine particles, fillers, solvents, functional additives, color pastes, and rheology modifiers. The diamine compounds are at least one of ethylenediamine, propylenediamine, butylenediamine, pentanediamine, hexamethylenediamine, p-phenylenediamine, p-phenylenediamine, diaminobiphenyl, and diaminonaphthalene. The polydopamine particles are polymer particles formed by dopamine precipitation polymerization, with a particle size of 50-200 nm. Component B (curing agent) is prepared by mixing isocyanate and solvent. The mass ratio of component A (main agent) to component B (curing agent) is 1:(0.08~0.22).

2. The reflective heat-insulating coating with self-cleaning and self-repairing functions according to claim 1, characterized in that... The dopa-modified acrylamide is at least one of dopamine methacrylamide, dopamine acrylamide, dopa methacrylamide, and dopa acrylamide; wherein the molar mass ratio of the diamine compound and the dopa-modified acrylamide is 1:(1.8~2.2).

3. A reflective heat-insulating coating with self-cleaning and self-repairing functions as described in claim 1, characterized in that... In the main component A, the contents of fluorocarbon resin, diamine compounds, dopamine-modified acrylamide, polydopamine particles, fillers, solvents, functional additives, color pastes, and rheology modifiers are 50-65%, 0.5-1%, 1-5%, 3-6%, 15-25%, 3-10%, 0.5-3.5%, 0.1-2%, and 0.5-1.5% respectively, based on the total mass of component A; the fluorocarbon resin is at least one of water-based or solvent-based polyvinylidene fluoride resin, polychlorotrifluoroethylene-vinyl ether resin, or polychlorotetrafluoroethylene-vinyl ether resin. The filler is at least one of rutile titanium dioxide, potassium hexatitanate whiskers, ceramic hollow microspheres, hollow glass microspheres, and far-infrared ceramic powder; the solvent is at least one of xylene, acetone, butyl acetate, dimethylformamide, cyclic ether, propylene glycol methyl ether acetate, and water; the functional additive is at least one of dispersant, defoamer, leveling agent, adhesion promoter, and antioxidant; the color paste is at least one of black color pastes from Clariant, Degussa, Sibis, BASF, and Shiming; and the rheology modifier is at least one of bentonite, hydrated magnesium silicate, fumed silica, and polymer wax.

4. A reflective heat-insulating coating with self-cleaning and self-repairing functions as described in claim 1, characterized in that... In the curing agent of component B, the content of isocyanate and solvent is 85%-100% and 0-15% respectively, based on the total mass of component B; wherein the isocyanate is at least one selected from toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate, terephthalic diisocyanate, phenyl diisocyanate, hydrophilic HDI polyisocyanate, hydrophilic modified IPDI polyisocyanate, polymethylene polyphenyl polyisocyanate, toluene diisocyanate trimer, hexamethylene diisocyanate trimer, and hexamethylene diisocyanate biuret; the solvent is at least one selected from xylene, acetone, butyl acetate, dimethylformamide, cyclic ether, propylene glycol methyl ether acetate, and water.

5. The method for preparing a reflective heat-insulating coating with self-cleaning and self-repairing functions according to claim 1, characterized in that... The preparation method of component A (main agent) and component B (curing agent) includes the following steps: (1) Preparation of polydopamine particles: Water, alcohol solvent and ammonia water are prepared into a reaction solution. Dopamine hydrochloride and polyethylene glycol 2000 are added to the reaction solution. After complete dissolution, the reaction solution is heated to 65°C and reacted for 16 hours under mechanical stirring. After the reaction is completed, the reaction solution is centrifuged at high speed. After centrifugation, the precipitate is taken out, rinsed with deionized water and dried in a vacuum oven for 24 hours to obtain polydopamine particles. (2) Preparation of component A: Weigh appropriate amounts of each component, add diamine compounds and dopamine-modified acrylamide to fluorocarbon resin, and mechanically stir for 3 hours at 40-60℃. After the reaction, add filler and polydopamine particles to fluorocarbon resin. Disperse the mixture for 20 minutes at room temperature and linear velocity of 3-5 m / s using a high-speed disperser, and then treat it with an ultrasonic disperser for 4-10 minutes to obtain mixture Aa. Mix the solvent, functional additives, color paste and rheology modifier at room temperature, pre-disperse it for 5 minutes at low speed using a high-speed disperser, let it stand for 10 minutes, and then disperse it at a high speed of 18-24 m / s for 10 minutes to obtain mixture Ab. Add mixture Ab to mixture Aa at a linear velocity of 6-10 m / s and disperse for 5-10 minutes until the system is homogeneous and stable to obtain component A. (3) Preparation of component B curing agent: The isocyanate and solvent are dispersed and mixed for 10-15 min until the system is homogeneous and stable to obtain component B curing agent.

6. The method for preparing a reflective heat-insulating coating with self-cleaning and self-repairing functions according to claim 5, characterized in that... The reaction solution consists of 60% water, 38% alcohol solvent and 2% ammonia, wherein the alcohol solvent is at least one of methanol, ethanol and isopropanol; the reaction concentration of dopamine hydrochloride is 0.5-1.5%; and the reaction concentration of polyethylene glycol 2000 is 0.05-0.2%.

7. A reflective heat-insulating coating with self-cleaning and self-repairing functions as described in claim 1, characterized in that... It requires mixing component A (main agent) and component B (curing agent) evenly before application. The dry film thickness of the reflective heat insulation coating after application is 120-200μm.

8. A reflective heat-insulating coating with self-cleaning and self-repairing functions as described in claim 1, characterized in that... The on-site application method for the coating is any one of spraying, dipping, rolling, and brushing.

9. The application of the self-cleaning and self-repairing reflective heat-insulating coating as described in claim 1 as a surface temperature control material for industrial storage tanks, transportation infrastructure, and building structures.