A corrosion-resistant and cooling coating and its preparation method

Abstract

This invention relates to the field of thermal management coatings, and more particularly to an anti-corrosion and cooling coating and its preparation method. The anti-corrosion and cooling coating of this invention comprises a composite nano-functional filler, a photosensitive polydimethylsiloxane-lipoic acid composite, and an organosilicon polyurethane matrix. The composite nano-functional filler includes metal particles, a dispersant, solvent α, and inorganic fillers. The photosensitive polydimethylsiloxane-lipoic acid composite includes hydroxypropyl-terminated polydimethylsiloxane, lipoic acid, 4-dimethylaminopyridine, a dehydrating agent, and solvent β. The organosilicon polyurethane matrix includes dimethyl-terminated polydimethylsiloxane, polyisocyanate, polyamine or polyol, a diamino / hydroxyl disulfide compound, and solvent β. This coating exhibits excellent surface hydrophobicity, anti-corrosion properties, thermal conductivity, radiative cooling performance, and low elastic modulus characteristics, constructing a cooling system that synergistically combines active and passive modes, and possesses self-healing properties.

Description

Technical Field

[0001] This invention relates to the field of thermal management coatings, and in particular to an anti-corrosion and cooling coating and its preparation method. Background Technology

[0002] With the rapid development of modern industry and infrastructure construction, outdoor facilities, building facades, and electrical equipment, which are exposed to complex environments for extended periods, face multiple challenges such as high temperatures, corrosion, and UV aging. Traditional protective coatings often have limited functionality and cannot simultaneously meet the comprehensive requirements of corrosion protection, heat dissipation, and long-term stability. Especially against the backdrop of frequent extreme weather events and increasingly stringent energy efficiency requirements, the development of a multi-functional coating that integrates long-term corrosion protection, rapid heat conduction, and radiative cooling has become an urgent need in the field of thermal management coatings technology.

[0003] Currently, protective coatings on the market are mainly divided into two categories: one is primarily for corrosion prevention, such as epoxy resin and polyurethane coatings, which isolate water and oxygen through a dense barrier, but have poor thermal conductivity (usually below 0.2 W / m·K), leading to heat accumulation and accelerated coating aging; the other is primarily for heat dissipation, using thermally conductive coatings with added metal fillers. Although this can improve thermal conductivity (1–5 W / m·K), it is prone to corrosion due to high electrochemical activity and lacks the ability to actively regulate solar radiation. Furthermore, while radiation-cooling coatings (such as SiO2 / TiO2 systems) can emit infrared radiation for cooling through an 8–13 μm atmospheric window, they have low mechanical strength and poor environmental tolerance, making them unsuitable for long-term outdoor use. This disconnect in performance urgently needs to be addressed through material design and structural innovation.

[0004] Although existing research has attempted to combine functions such as using graphene for corrosion protection and thermal conductivity, the problem of infrared modulation has not been solved. The core difficulties are that while high filler loading improves thermal conductivity, it reduces the flexibility and adhesion of the coating; single nanomaterials are prone to oxidation and agglomeration, leading to performance degradation; and the ordered microstructure (such as directional alignment) requires complex processes, making low-cost mass production difficult.

[0005] Therefore, how to provide a nanocomposite coating based on the synergistic regulation of microstructure and interface chemistry, which has the functions of long-term corrosion protection, rapid heat conduction and radiative cooling, has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide an anti-corrosion and cooling coating and its preparation method, which uses micro-nano particles with high thermal conductivity and high infrared emissivity as the main functional filler to improve the coating's thermal conductivity, infrared conversion and emission efficiency, and high solar reflectance.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0008] This invention provides an anti-corrosion and cooling coating, comprising the following components in parts by weight: 1-20 parts of composite nano-functional filler, 1-20 parts of photosensitive polydimethylsiloxane-lipoic acid composite, and 23-230 parts of organosilicon polyurethane matrix.

[0009] The composite nanofunctional filler comprises the following components in parts by mass: 1-100 parts of metal particles, 1-100 parts of dispersant, 100-1000 parts of solvent α, and 1-100 parts of inorganic filler.

[0010] The photosensitive polydimethylsiloxane-lipoic acid composite comprises the following components in parts by weight: 10-100 parts of hydroxypropyl-terminated polydimethylsiloxane, 10-100 parts of lipoic acid, 10-100 parts of 4-dimethylaminopyridine, 10-100 parts of dehydrating agent, and 100-1000 parts of solvent β.

[0011] The organosilicon polyurethane matrix comprises the following components in parts by weight: 10-100 parts of di-terminated polydimethylsiloxane, 1-10 parts of polyisocyanate, 1-10 parts of polyamine or polyol, 1-10 parts of diamino / hydroxyl disulfide compound, and 10-100 parts of solvent β.

[0012] Optionally, the metal particles include one or more of zinc powder, aluminum powder, copper powder, silver powder, stainless steel powder, nickel powder, titanium powder, molybdenum powder, and tin powder;

[0013] The inorganic filler includes one or more of boron nitride, silicon carbide, aluminum oxide, titanium dioxide, barium sulfate, ferrous oxide, copper oxide, zinc oxide, zirconium oxide, lead carbonate, magnesium carbonate, magnesium oxide, calcium carbonate, and silicon dioxide.

[0014] Optionally, the dispersant includes one or more of BYK-110, BYK-2080, EFKA-4010, sodium polycarboxylate, aminopropyltrimethoxysilane, aminopropyltriethoxysilane, and sodium dodecylbenzenesulfonate.

[0015] Optionally, the weight-average molecular weight of the hydroxypropyl-terminated polydimethylsiloxane is 1000 to 10000.

[0016] Optionally, the dehydrating agent includes one or more of trifluoromethylbenzoic anhydride, anhydrous aluminum sulfate, and N,N'-dicyclohexylcarbodiimide.

[0017] Optionally, the solvent α includes one or more of water, methanol, ethanol, xylene, ethyl acetate, tetrahydrofuran, acetone, and dichloromethane;

[0018] The solvent β includes one or more of tetrahydrofuran, acetone, dichloromethane, xylene, N,N-dimethylformamide, ethyl acetate, and butyl acetate.

[0019] Optionally, the weight-average molecular weight of the dimethylsiloxane is 1,000 to 10,000, and the diterminal groups in its molecular formula are one or more of hydroxypropyl, aminopropyl, and epoxy groups.

[0020] Optionally, the polyisocyanate includes diisocyanate or triisocyanate;

[0021] The diamino / hydroxy disulfide compounds include one or more of 4,4'-diaminodiphenyl disulfide, bis(4-hydroxyphenyl) disulfide, 2,2'-diaminodiphenyl disulfide, bis(2-hydroxyethyl) disulfide, and 3,3'-dihydroxydiphenyl disulfide.

[0022] Optionally, the polyol includes one or both of glycerol and butanediol; the polyamine includes one or both of triethylamine and hexamethylenediamine.

[0023] This invention also provides a method for preparing the above-mentioned anti-corrosion and cooling coating, comprising the following steps:

[0024] Metal particles, dispersant, solvent α and inorganic filler are mixed and stirred at 0-40℃ for 10-24h to obtain composite nanofunctional filler;

[0025] Hydroxypropyl-terminated polydimethylsiloxane, thioctic acid, 4-dimethylaminopyridine, dehydrating agent and solvent β were mixed and stirred at 20-60°C for 10-24 h to obtain a photosensitive polydimethylsiloxane-thioctic acid complex.

[0026] A double-terminated polydimethylsiloxane, a polyisocyanate, and solvent β are mixed and reacted under an inert atmosphere and at 60–80°C for 1–4 h to obtain an isocyanate-terminated prepolymer. A diamino / hydroxyl disulfide compound, a polyamine, or a polyol is added to the isocyanate-terminated prepolymer and reacted under an inert atmosphere and at 60–80°C for 1–4 h to obtain an organosilicon polyurethane matrix.

[0027] The anti-corrosion and cooling coating is obtained by mixing the composite nano-functional filler, the photosensitive polydimethylsiloxane-thioctic acid composite and the organosilicon polyurethane matrix.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) Starting from the regulation of interface microstructure, the addition of photosensitive material and one-step photocuring process are used to avoid the use of complex surface treatment technologies such as traditional surface laser etching and multi-layer composite process, which is more universal and can be expanded on a large scale.

[0030] (2) By effectively combining a high emissivity polymer skeleton with a high refractive index metal / inorganic particles, the material is endowed with excellent radiation cooling performance, which breaks through the incompatibility problem between anti-corrosion and heat conduction functions and radiation cooling performance.

[0031] (3) The anti-corrosion and cooling coating prepared by the present invention has excellent surface hydrophobicity, radiation cooling performance and low elastic modulus characteristics. It constructs a cooling system with active and passive modes working together and has certain self-healing properties. Compared with traditional cooling coatings, it has multi-functional characteristics. Attached Figure Description

[0032] Figure 1 This is a three-dimensional topographic image of the coating surface in Example 1;

[0033] Figure 2 This is a three-dimensional topographic image of the coating surface in Example 2;

[0034] Figure 3 This is a three-dimensional topographic image of the coating surface in Example 3;

[0035] Figure 4 Scanning electron microscope image of the coating in Example 3. Detailed Implementation

[0036] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0037] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0038] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0039] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This application specification and embodiments are merely exemplary.

[0040] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0041] All raw materials used in this invention can be obtained commercially or prepared using existing technologies.

[0042] The present invention provides an anti-corrosion and cooling coating comprising the following components in parts by weight: 1-20 parts of composite nano-functional filler, 1-20 parts of photosensitive polydimethylsiloxane-lipoic acid composite and 23-230 parts of organosilicon polyurethane matrix;

[0043] The composite nanofunctional filler comprises the following components in parts by mass: 1-100 parts of metal particles, 1-100 parts of dispersant, 100-1000 parts of solvent α, and 1-100 parts of inorganic filler.

[0044] The photosensitive polydimethylsiloxane-lipoic acid composite comprises the following components in parts by weight: 10-100 parts of hydroxypropyl-terminated polydimethylsiloxane, 10-100 parts of lipoic acid, 10-100 parts of 4-dimethylaminopyridine, 10-100 parts of dehydrating agent, and 100-1000 parts of solvent β.

[0045] The organosilicon polyurethane matrix comprises the following components in parts by weight: 10-100 parts of di-terminated polydimethylsiloxane, 1-10 parts of polyisocyanate, 1-10 parts of polyamine or polyol, 1-10 parts of diamino / hydroxyl disulfide compound, and 10-100 parts of solvent β.

[0046] This invention utilizes micro / nano particles with high thermal conductivity and high infrared emissivity as the main functional filler to improve the coating's thermal conductivity, infrared conversion and emission efficiency, and high solar reflectivity. By using specific metal particles and inorganic fillers to improve the coating's thermal conductivity, the degree of photocuring crosslinking is altered by adjusting the amount of photosensitive polydimethylsiloxane-lipoic acid composite. Different degrees of crosslinking change the mobility of the metal particles and inorganic fillers within the polymer matrix, resulting in variations in particle size and dispersion. This creates a highly efficient thermally conductive three-dimensional anti-corrosion network structure within the coating, macroscopically manifested as differences in the surface wrinkle morphology and size. Modifying the filler-matrix interface with a silane coupling agent reduces phonon scattering, improves thermal conductivity, and enhances interfacial bonding, inhibiting the penetration of corrosive media. The high reflectivity layer for visible and infrared light irradiation is formed on the coating surface by the gravity settling and capillary forces of the micro / nano fillers, resulting in a coating that integrates high thermal conductivity, infrared radiation, and solar radiation reflection.

[0047] In this invention, the anti-corrosion and cooling coating includes 1 to 20 parts of composite nano-functional filler, for example, 1 part, 5 parts, 10 parts, 15 parts or 20 parts, etc.

[0048] In this invention, the composite nanofunctional filler comprises 1 to 100 parts of metal particles, for example, 1 part, 5 parts, 10 parts, 15 parts, 25 parts, 35 parts, 40 parts, 50 parts, 60 parts, 70 parts, 80 parts, 90 parts or 100 parts, etc.

[0049] The metal particles include one or more of zinc powder, aluminum powder, copper powder, silver powder, stainless steel powder, nickel powder, titanium powder, molybdenum powder, and tin powder.

[0050] In this invention, the composite nanofunctional filler includes 1 to 100 parts of dispersant, for example, it can be 1 part, 5 parts, 10 parts, 15 parts, 25 parts, 35 parts, 40 parts, 50 parts, 60 parts, 70 parts, 80 parts, 90 parts or 100 parts, etc.

[0051] The dispersant includes one or more of BYK-110, BYK-2080, EFKA-4010, sodium polycarboxylate, aminopropyltrimethoxysilane, aminopropyltriethoxysilane, and sodium dodecylbenzenesulfonate.

[0052] In this invention, the composite nanofunctional filler comprises solvent α of 100 to 1000 parts, for example, 100 parts, 200 parts, 300 parts, 400 parts, 500 parts, 600 parts, 700 parts, 800 parts, 900 parts or 1000 parts, etc.

[0053] The solvent α includes one or more of water, methanol, ethanol, xylene, ethyl acetate, tetrahydrofuran, acetone, and dichloromethane.

[0054] In this invention, the composite nanofunctional filler comprises 1 to 100 parts of inorganic filler, for example, 1 part, 5 parts, 10 parts, 15 parts, 25 parts, 35 parts, 40 parts, 50 parts, 60 parts, 70 parts, 80 parts, 90 parts or 100 parts, etc.

[0055] The inorganic filler includes one or more of boron nitride, silicon carbide, aluminum oxide, titanium dioxide, barium sulfate, ferrous oxide, copper oxide, zinc oxide, zirconium oxide, lead carbonate, magnesium carbonate, magnesium oxide, calcium carbonate, and silicon dioxide.

[0056] In this invention, the anti-corrosion and cooling coating includes 1 to 20 parts of a photosensitive polydimethylsiloxane-thioctic acid composite, for example, 1 part, 5 parts, 10 parts, 15 parts or 20 parts.

[0057] In this invention, the photosensitive polydimethylsiloxane-lipoic acid complex comprises 10 to 100 parts of hydroxypropyl-terminated polydimethylsiloxane, for example, 10 parts, 15 parts, 25 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 90 parts, or 100 parts, etc.

[0058] The weight-average molecular weight of the hydroxypropyl-terminated polydimethylsiloxane is 1,000 to 10,000, for example, it can be 1,000, 2,000, 3,000, 4,000, 5,000, 6,000, 7,000, 8,000, 9,000 or 10,000.

[0059] In this invention, the photosensitive polydimethylsiloxane-lipoic acid complex comprises 10 to 100 parts of lipoic acid, for example, 10 parts, 15 parts, 25 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 90 parts, or 100 parts.

[0060] In this invention, the photosensitive polydimethylsiloxane-lipoic acid complex comprises 10 to 100 parts of 4-dimethylaminopyridine, for example, 10 parts, 15 parts, 25 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 90 parts, or 100 parts.

[0061] In this invention, the photosensitive polydimethylsiloxane-lipoic acid complex includes 10 to 100 parts of a dehydrating agent, for example, 10 parts, 15 parts, 25 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 90 parts, or 100 parts, etc.

[0062] The dehydrating agent includes one or more of trifluoromethylbenzoic anhydride, anhydrous aluminum sulfate, and N,N'-dicyclohexylcarbodiimide.

[0063] In this invention, the photosensitive polydimethylsiloxane-lipoic acid composite comprises solvent β 100 to 1000 parts, for example, 100 parts, 200 parts, 300 parts, 400 parts, 500 parts, 600 parts, 700 parts, 800 parts, 900 parts or 1000 parts, etc.

[0064] The solvent β includes one or more of tetrahydrofuran, acetone, dichloromethane, xylene, N,N-dimethylformamide, ethyl acetate, and butyl acetate.

[0065] In this invention, the anti-corrosion and cooling coating comprises 23 to 230 parts of an organosilicon polyurethane base, for example, 23 parts, 30 parts, 40 parts, 50 parts, 56 parts, 60 parts, 68 parts, 75 parts, 80 parts, 90 parts, 92 parts, 115 parts, 130 parts, 150 parts, 180 parts, 200 parts, or 230 parts, etc.

[0066] In this invention, the organosilicon polyurethane body comprises 10 to 100 parts of dimethylsiloxane, for example, 10 parts, 15 parts, 25 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 90 parts, or 100 parts.

[0067] The weight-average molecular weight of the dimethylsiloxane is 1,000 to 10,000, for example, it can be 1,000, 2,000, 3,000, 4,000, 5,000, 6,000, 7,000, 8,000, 9,000 or 10,000; the diterminal groups in its molecular formula are one or more of hydroxypropyl, aminopropyl and epoxy groups, preferably aminopropyl or epoxy groups.

[0068] In this invention, the organosilicon polyurethane body comprises 1 to 10 parts of polyisocyanate, for example, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts or 10 parts, etc.

[0069] The polyisocyanate includes diisocyanate or triisocyanate, and is preferably one or more of hexamethylene diisocyanate, triphenylmethane triisocyanate, diphenylmethane diisocyanate and isophorone diisocyanate.

[0070] In this invention, the organosilicon polyurethane body comprises 1 to 10 parts of polyamine or polyol, for example, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts or 10 parts, etc.

[0071] The polyol includes one or both of glycerol and butanediol; the polyamine includes one or both of triethylamine and hexamethylenediamine.

[0072] In this invention, the organosilicon polyurethane body comprises 1 to 10 parts of a diamino / hydroxyl disulfide compound, for example, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, or 10 parts, etc.

[0073] The diamino / hydroxy disulfide compounds include one or more of 4,4'-diaminodiphenyl disulfide, bis(4-hydroxyphenyl) disulfide, 2,2'-diaminodiphenyl disulfide, bis(2-hydroxyethyl) disulfide, and 3,3'-dihydroxydiphenyl disulfide.

[0074] In this invention, the organosilicon polyurethane body includes solvent β10 to 100 parts, for example, it can be 10 parts, 15 parts, 25 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 90 parts or 100 parts, etc.

[0075] In this invention, a method for preparing the above-mentioned anti-corrosion and cooling coating is also provided, comprising the following steps:

[0076] Metal particles, dispersant, solvent α and inorganic filler are mixed and stirred at 0-40℃ for 10-24h to obtain composite nanofunctional filler;

[0077] In an embodiment of the present invention, metal particles and a dispersant are dispersed in solvent α, followed by the addition of inorganic filler, and the mixture is stirred at 0–40°C for 10–24 h. After centrifugation to obtain a solid, the solid is washed with solvent α and centrifuged again. The solid is then freeze-dried to obtain a composite nano-functional filler.

[0078] The stirring temperature is 0 to 40°C, for example, it can be 0°C, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C or 40°C, etc.

[0079] The stirring time is 10 to 24 hours, for example, 10 hours, 12 hours, 15 hours, 16 hours, 20 hours or 24 hours.

[0080] Hydroxypropyl-terminated polydimethylsiloxane, thioctic acid, 4-dimethylaminopyridine, dehydrating agent and solvent β were mixed and stirred at 20-60°C for 10-24 h to obtain a photosensitive polydimethylsiloxane-thioctic acid complex.

[0081] In an embodiment of the present invention, hydroxypropyl-terminated polydimethylsiloxane, thioctic acid, 4-dimethylaminopyridine and a dehydrating agent are dissolved in solvent β and stirred at 20-60°C for 10-24 hours. The reaction solution is then filtered, neutralized with an acid solution, washed repeatedly with deionized water and separated to obtain a photosensitive polydimethylsiloxane-thioctic acid complex.

[0082] The stirring temperature is 20-60℃, for example, it can be 20℃, 25℃, 30℃, 35℃, 40℃, 45℃, 50℃, 55℃ or 60℃, etc.

[0083] The stirring time is 12 to 24 hours, for example, it can be 10 hours, 12 hours, 15 hours, 16 hours, 20 hours or 24 hours, etc.

[0084] The acidic solution includes one or more of hydrochloric acid, acetic acid, sulfuric acid, and oxalic acid.

[0085] A double-terminated polydimethylsiloxane, a polyisocyanate, and solvent β are mixed and reacted under an inert atmosphere and at 60–80°C for 1–4 h to obtain an isocyanate-terminated prepolymer. A diamino / hydroxyl disulfide compound, a polyamine, or a polyol is added to the isocyanate-terminated prepolymer and reacted under an inert atmosphere and at 60–80°C for 1–4 h to obtain an organosilicon polyurethane matrix.

[0086] In an embodiment of the present invention, a diamino / hydroxyl disulfide compound, a polyisocyanate and a solvent β are mixed evenly and reacted under an inert atmosphere and at 60-80°C for 1-4 hours to obtain an isocyanate-terminated prepolymer. A diamino / hydroxyl disulfide compound, a polyamine or a polyol is then added to the isocyanate-terminated prepolymer, mixed evenly and reacted under an inert atmosphere and at 60-80°C for 1-4 hours to obtain an organosilicon polyurethane matrix.

[0087] The reaction temperature is 60–80°C, for example, it can be 60°C, 65°C, 70°C, 75°C or 80°C, etc.

[0088] The reaction time is 1 to 4 hours, for example, it can be 1 hour, 2 hours, 3 hours or 4 hours, etc.

[0089] The inert atmosphere is preferably nitrogen.

[0090] The anti-corrosion and cooling coating is obtained by mixing the composite nano-functional filler, the photosensitive polydimethylsiloxane-thioctic acid composite and the organosilicon polyurethane matrix.

[0091] In an embodiment of the present invention, the anti-corrosion and cooling coating is obtained by uniformly mixing and dispersing the composite nano-functional filler, the photosensitive polydimethylsiloxane-thioctic acid composite and the organosilicon polyurethane matrix.

[0092] The present invention further provides a method for using the anti-corrosion and cooling coating, specifically: cleaning the surface to be sprayed, uniformly applying the anti-corrosion and cooling coating to the surface by air spraying, and fully drying it under normal sunlight or ultraviolet light to obtain a self-wrinkling long-lasting anti-corrosion and cooling coating; wherein, the coating thickness of the wet film is 100-1000μm, for example, it can be 100μm, 150μm, 200μm, 250μm, 300μm, 350μm, 400μm, 500μm, 600μm, 700μm, 800μm, 900μm or 1000μm, etc.

[0093] The long-lasting anti-corrosion and cooling coating prepared by this invention effectively combines anti-corrosion, wear resistance, thermal conductivity and radiative cooling properties, bringing new possibilities for the rational design and sustainable development of next-generation intelligent cooling coatings. It can be widely used in the fields of heat dissipation control and protection of outdoor facilities, building exterior walls and power equipment.

[0094] Understandably, passive cooling coatings based on radiative cooling have attracted much attention due to their environmental friendliness, high efficiency, and long-lasting corrosion resistance. However, the design challenge of such coatings lies in maximizing surface infrared emission and solar reflectance, and optimizing the internal thermal conductivity network. Currently, two common strategies are optimizing the broad-spectrum absorption characteristics of photosensitive materials and constructing special microstructures to enhance surface light conversion capabilities. Surface modification techniques such as laser etching are time-consuming and energy-intensive, with complex preparation methods and difficulty in adapting to different substrate surfaces. In contrast, one-step photocuring methods are simpler and more universal. This invention is based on a nanocomposite coating synergistically regulated by microstructure and interface chemistry. Through the esterification reaction of dimethylsiloxane and thioctic acid, a photosensitive polydimethylsiloxane-thioctic acid composite is constructed. Under ultraviolet light irradiation, the monomers undergo ring-opening polymerization to form a three-dimensional cross-linked network structure, which in turn forms an interpenetrating network structure with an organosilicon matrix. This further synergistically composites nanophotothermal materials, allowing for the preparation of a microstructure-tunable, self-wrinkled, long-lasting corrosion-resistant and cooling coating via a one-step photocuring method.

[0095] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0096] Example 1

[0097] (1) Preparation of composite nano-functional fillers:

[0098] Ten parts by weight of metallic nickel, ten parts by weight of dispersant BYK110, and 100 parts by weight of deionized water were ultrasonically dispersed. Then, ten parts by weight of boron nitride were added, and the mixture was stirred at 0°C for 24 hours. After centrifugation to obtain a solid, the solid was washed with deionized water and centrifuged again. The solid was then freeze-dried to obtain a composite nano-functional filler.

[0099] (2) Preparation of photosensitive polydimethylsiloxane-lipoic acid complex:

[0100] Ten parts by weight of hydroxypropyl-terminated polydimethylsiloxane (molecular weight 1000), ten parts by weight of thioctic acid, ten parts by weight of 4-dimethylaminopyridine, and ten parts by weight of trifluoromethylbenzoic anhydride were dissolved in 100 parts by weight of tetrahydrofuran and stirred at 20°C for 24 h. The reaction solution was then filtered, neutralized with sulfuric acid solution, washed repeatedly with deionized water, and separated to obtain a photosensitive polydimethylsiloxane-thioctic acid complex.

[0101] (3) Preparation of the silicone polyurethane matrix for coating:

[0102] Take 10 parts by weight of hydroxypropyl-terminated polydimethylsiloxane (molecular weight 1000), 1 part by weight of hexamethylene diisocyanate and 10 parts by weight of tetrahydrofuran, mix them well and heat them at 60°C for 4 hours under a nitrogen atmosphere to obtain an isocyanate-terminated prepolymer. Then add 1 part by weight of 4,4'-diaminodiphenyl disulfide and 1 part by weight of triethylamine, mix them well and heat them at 60°C for 4 hours under a nitrogen atmosphere to prepare an organosilicon polyurethane liquid as the main polymer for coatings.

[0103] (4) Preparation of anti-corrosion and cooling coatings:

[0104] Five parts by weight of the composite nano-functional filler prepared in (1) and five parts by weight of the photosensitive polydimethylsiloxane-thioctic acid composite prepared in (2) were added to the silicone polyurethane liquid prepared in (3) and dispersed evenly to obtain a long-lasting anti-corrosion and cooling coating.

[0105] (5) Application method of long-lasting anti-corrosion and cooling coating: Clean the surface to be sprayed, and apply the anti-corrosion and cooling coating evenly to the surface by air spraying. The wet film coating thickness is 100μm. Dry it fully under ultraviolet light to obtain a long-lasting anti-corrosion and cooling coating.

[0106] Example 2

[0107] (1) Preparation of composite nano-functional fillers:

[0108] 20 parts by weight of zinc metal and 15 parts by weight of dispersant BYK2080 were ultrasonically dispersed in 200 parts by weight of ethanol. Then, 20 parts by weight of silicon carbide were added, and the mixture was stirred at 20°C for 18 hours. After centrifugation to obtain a solid, the solid was washed with ethanol and centrifuged again. The solid was then freeze-dried to obtain a composite nano-functional filler.

[0109] (2) Preparation of photosensitive polydimethylsiloxane-lipoic acid complex:

[0110] 20 parts by weight of hydroxypropyl-terminated polydimethylsiloxane (molecular weight 2000), 20 parts by weight of thioctic acid, 20 parts by weight of 4-dimethylaminopyridine, and 25 parts by weight of anhydrous aluminum sulfate were dissolved in 250 parts by weight of dichloromethane and stirred at 30°C for 18 hours. The reaction solution was then filtered, neutralized with hydrochloric acid solution, washed repeatedly with deionized water, and separated to obtain a photosensitive polydimethylsiloxane-thioctic acid complex.

[0111] (3) Preparation of the silicone polyurethane matrix for coating:

[0112] Take 25 parts by weight of diaminopropyl-terminated polydimethylsiloxane (molecular weight 2500), 2 parts by weight of triphenylmethane triisocyanate and 25 parts by weight of acetone, mix them well and heat them at 70°C for 3 hours under a nitrogen atmosphere to obtain an isocyanate-terminated prepolymer. Then add 2 parts by weight of bis(4-hydroxyphenyl)disulfide and 2 parts by weight of glycerol, mix them well and heat them at 65°C for 3 hours under a nitrogen atmosphere to prepare an organosilicon polyurethane liquid as the main polymer for coatings.

[0113] (4) Preparation of anti-corrosion and cooling coatings:

[0114] In the silicone polyurethane liquid prepared in (3), 10 parts by weight of the composite nano-functional filler prepared in (1) and 10 parts by weight of the photosensitive polydimethylsiloxane-thioctic acid composite prepared in (2) are added and dispersed evenly to obtain a long-lasting anti-corrosion and cooling coating.

[0115] (5) Application method of long-lasting anti-corrosion and cooling coating: Clean the surface to be sprayed, and apply the anti-corrosion and cooling coating evenly to the surface by air spraying. The wet film coating thickness is 200μm. Dry it fully under ultraviolet light to obtain a long-lasting anti-corrosion and cooling coating.

[0116] Example 3

[0117] (1) Preparation of composite nano-functional fillers:

[0118] 25 parts by weight of copper powder and 25 parts by weight of sodium dodecylbenzenesulfonate dispersant were ultrasonically dispersed in 300 parts by weight of dichloromethane. Then, 25 parts by weight of boron nitride were added, and the mixture was stirred at 30°C for 12 hours. After centrifugation to obtain a solid, the solid was washed with dichloromethane and centrifuged again. The solid was then freeze-dried to obtain a composite nano-functional filler.

[0119] (2) Preparation of photosensitive polydimethylsiloxane-lipoic acid complex:

[0120] 30 parts by weight of hydroxypropyl-terminated polydimethylsiloxane (molecular weight 2500), 30 parts by weight of thioctic acid, 30 parts by weight of 4-dimethylaminopyridine, and 30 parts by weight of N,N'-dicyclohexylcarbodiimide were dissolved in 400 parts by weight of ethyl acetate and stirred at 40°C for 12 h. The reaction solution was then filtered, neutralized with acetic acid solution, washed repeatedly with deionized water, and separated to obtain a photosensitive polydimethylsiloxane-thioctic acid complex.

[0121] (3) Preparation of the silicone polyurethane matrix for coating:

[0122] Take 30 parts by weight of diepoxy-terminated polydimethylsiloxane (molecular weight 3000), 2 parts by weight of diphenylmethane diisocyanate and 30 parts by weight of ethyl acetate, mix them well and heat them at 75°C for 3 hours under a nitrogen atmosphere to obtain an isocyanate-terminated prepolymer. Then add 3 parts by weight of 2,2'-diaminodiphenyl disulfide and 3 parts by weight of butanediol, mix them well and heat them at 75°C for 3 hours under a nitrogen atmosphere to prepare an organosilicon polyurethane liquid as the main polymer for coatings.

[0123] (4) Preparation of anti-corrosion and cooling coatings:

[0124] Add 15 parts by weight of the composite nano-functional filler prepared in (1) and 15 parts by weight of the photosensitive polydimethylsiloxane-thioctic acid composite prepared in (2) to the silicone polyurethane liquid prepared in (3), and disperse evenly to obtain a long-lasting anti-corrosion and cooling coating.

[0125] (5) Application method of long-lasting anti-corrosion and cooling coating: Clean the surface to be sprayed, and apply the anti-corrosion and cooling coating evenly to the surface by air spraying. The wet film coating thickness is 300μm. Dry it fully under ultraviolet light to obtain a long-lasting anti-corrosion and cooling coating.

[0126] Example 4

[0127] (1) Preparation of composite nano-functional fillers:

[0128] 30 parts by weight of stainless steel powder and 25 parts by weight of dispersant aminopropyltriethoxysilane were ultrasonically dispersed in 400 parts by weight of acetone. Then, 30 parts by weight of alumina were added, and the mixture was stirred at 35°C for 12 hours. After centrifugation to obtain a solid, the solid was washed with acetone and centrifuged again. The solid was then freeze-dried to obtain a composite nano-functional filler.

[0129] (2) Preparation of photosensitive polydimethylsiloxane-lipoic acid complex:

[0130] 40 parts by weight of hydroxypropyl-terminated polydimethylsiloxane (molecular weight 4000), 40 parts by weight of thioctic acid, 40 parts by weight of 4-dimethylaminopyridine, and 40 parts by weight of trifluoromethylbenzoic anhydride were dissolved in 500 parts by weight of butyl acetate and stirred at 45°C for 12 h. The reaction solution was then filtered, neutralized with sulfuric acid solution, washed repeatedly with deionized water, and separated to obtain a photosensitive polydimethylsiloxane-thioctic acid complex.

[0131] (3) Preparation of the silicone polyurethane matrix for coating:

[0132] 40 parts by weight of hydroxypropyl-terminated polydimethylsiloxane (molecular weight 4000), 4 parts by weight of isophorone diisocyanate and 40 parts by weight of butyl acetate were mixed and heated at 80°C for 2 hours under a nitrogen atmosphere to obtain an isocyanate-terminated prepolymer. Then, 4 parts by weight of bis(2-hydroxyethyl) disulfide and 4 parts by weight of hexamethylenediamine were added, mixed, and heated at 80°C for 2 hours under a nitrogen atmosphere to prepare an organosilicon polyurethane liquid as the main polymer for coatings.

[0133] (4) Preparation of anti-corrosion and cooling coatings:

[0134] Add 20 parts by weight of the composite nano-functional filler prepared in (1) and 20 parts by weight of the photosensitive polydimethylsiloxane-thioctic acid composite prepared in (2) to the silicone polyurethane liquid prepared in (3), and disperse evenly to obtain a self-wrinkling long-lasting anti-corrosion and cooling coating.

[0135] (5) Application method of long-lasting anti-corrosion and cooling coating: Clean the surface to be sprayed, and apply the anti-corrosion and cooling coating evenly to the surface by air spraying. The wet film coating thickness is 400μm. Dry it fully under ultraviolet light to obtain a long-lasting anti-corrosion and cooling coating.

[0136] Example 5

[0137] (1) Preparation of composite nano-functional fillers:

[0138] 35 parts by weight of silver powder and 30 parts by weight of dispersant aminopropyltriethoxysilane were ultrasonically dispersed in 400 parts by weight of deionized water. Then, 35 parts by weight of barium sulfate were added, and the mixture was stirred at 40°C for 10 hours. After centrifugation to obtain a solid, the solid was washed with deionized water and centrifuged again to obtain another solid. The composite nano-functional filler was obtained by freeze-drying.

[0139] (2) Preparation of photosensitive polydimethylsiloxane-lipoic acid complex:

[0140] 50 parts by weight of hydroxypropyl-terminated polydimethylsiloxane (molecular weight 5000), 50 parts by weight of thioctic acid, 50 parts by weight of 4-dimethylaminopyridine, and 50 parts by weight of N,N'-dicyclohexylcarbodiimide were dissolved in 500 parts by weight of N,N-dimethylformamide and stirred at 50°C for 10 h. The reaction solution was then filtered, neutralized with hydrochloric acid solution, washed repeatedly with deionized water, and separated to obtain a photosensitive polydimethylsiloxane-thioctic acid complex.

[0141] (3) Preparation of the silicone polyurethane matrix for coating:

[0142] Take 50 parts by weight of diaminopropyl-terminated polydimethylsiloxane (molecular weight 5000), 5 parts by weight of hexamethylene diisocyanate and 50 parts by weight of N,N-dimethylformamide, mix them well and heat them at 80°C for 2 hours under a nitrogen atmosphere to obtain an isocyanate-terminated prepolymer. Then add 5 parts by weight of 4,4'-diaminodiphenyl disulfide and 5 parts by weight of triethylamine, mix them well and heat them at 80°C for 2 hours under a nitrogen atmosphere to prepare an organosilicon polyurethane liquid as the main polymer for coatings.

[0143] (4) Preparation of anti-corrosion and cooling coatings:

[0144] In the silicone polyurethane liquid prepared in (3), 10 parts by weight of the composite nano-functional filler prepared in (1) and 10 parts by weight of the photosensitive polydimethylsiloxane-thioctic acid composite prepared in (2) are added and dispersed evenly to obtain a self-wrinkling anti-corrosion and cooling coating.

[0145] (5) Application method of long-lasting anti-corrosion and cooling coating: Clean the surface to be sprayed, and apply the anti-corrosion and cooling coating evenly to the surface by air spraying. The wet film coating thickness is 400μm. Dry it fully under ultraviolet light to obtain a long-lasting anti-corrosion and cooling coating.

[0146] Example 6

[0147] The only difference from Example 3 is that 30 parts by weight of copper powder are added during the preparation of the composite nanofunctional filler.

[0148] Example 7

[0149] The only difference from Example 3 is that the wet film coating thickness is 500 μm.

[0150] Performance evaluation:

[0151] Dow Corning 184 was used as Comparative Example 1, and Sigmadur 520 commercial anti-corrosion coating from Zhongtu Chemical was used as Comparative Example 2. The coatings of Comparative Example 1 and Comparative Example 2 were uniformly coated on the surface to be coated by air spraying. The wet film coating thickness was 300 μm. The coatings were fully dried under ultraviolet light to obtain the coating.

[0152] (1) Radiative cooling performance

[0153] The reflectance of the coating samples in the solar band (0.3–2.5 μm) was measured using a UV-Vis-NIR spectrophotometer equipped with a standard integrating sphere attachment. Simultaneously, the radiation characteristics of the coating in the mid-infrared band (2.5–25 μm) were measured using a Fourier transform infrared spectrometer equipped with an integrating sphere attachment.

[0154] The results of the radiation cooling performance test are shown in Table 1. The anti-corrosion and cooling coating of the present invention effectively reduces the surface temperature of the coating.

[0155] (2) Thermal conductivity

[0156] The thermal conductivity of the coating was measured according to GB / T 22588–2008 "Measuring Thermal Diffusion Coefficient or Thermal Conductivity by Flash Method". The test results of thermal conductivity are shown in Table 1.

[0157] (3) Corrosion resistance

[0158] Referring to GB / T 1771-2007, simulate marine or industrial corrosive environments to test the corrosion resistance of the coating. Further, immerse the coating in solutions such as 10% H2SO4 and 10% NaOH to observe how long it takes for the coating to blister and peel off.

[0159] Table 1 Comparison of test results between Examples 1-5 and Comparative Examples 1-2

[0160]

[0161] As shown in the examples and comparative examples in Table 1, the single silicone matrix and commercial anti-corrosion coatings exhibit low reflectivity and mid-infrared emissivity for sunlight, with almost no significant radiative cooling performance. However, with the introduction of functional nanocomposite fillers such as metal particles and inorganic fillers into the silicone polyurethane matrix, the coating exhibits a significant radiative cooling effect. The mid-infrared emissivity of the coating increases with the increase of inorganic lamellar content in the nanocomposite fillers. Examples 6 and 7 differ from Example 3 in that they adjust the content of metal particles and the coating thickness, respectively. The results show that increasing the metal particle content directly improves the thermal conductivity of the coating; however, the thermal conductivity decreases with increasing coating thickness. Compared to pure silicone materials, ordinary anti-corrosion coatings have a more significant salt spray resistance effect, but obviously, the reflectivity, emissivity, thermal conductivity, and salt spray resistance time are all lower than in the examples. The inorganic functional filler particle content and coating thickness in Example 3 are optimal. In Examples 4 and 5, the proportions and types of components in the nanofunctional filler were adjusted, and the resulting coating cooling ranges were all lower than those in Examples 1 and 2. Therefore, the proportions and types of metal particles and inorganic fillers in Example 1 are optimal.

[0162] Figure 1 This is a three-dimensional surface morphology image of the coating prepared in Example 1, by... Figure 1 It is known that the coating surface prepared by the present invention has a wrinkled microstructure and a roughness value Ra = 20.3 μm, which can achieve efficient emission and radiation of sunlight.

[0163] Figure 2 This is a three-dimensional surface morphology image of the coating prepared in Example 2, by... Figure 1 It is known that the coating surface prepared by the present invention has a wrinkled microstructure and a roughness value Ra = 13.5 μm, which can achieve efficient emission and radiation of sunlight.

[0164] Figure 3 This is a three-dimensional surface morphology image of the coating prepared in Example 3, by... Figure 1 It is known that the coating surface prepared by the present invention has a wrinkled microstructure and a roughness value Ra = 10.8 μm, which can achieve efficient emission and radiation of sunlight.

[0165] Figure 4 The scanning electron microscope image of the coating in Example 3 proves that the present invention has prepared a coating with a wrinkled microstructure on the surface.

[0166] In summary, this invention overcomes the technical bottlenecks of traditional microstructure processing by preparing surface-wrinkled microstructures through a one-step photopolymerization method. Furthermore, by optimizing the content of the photosensitive polydimethylsiloxane-lipoic acid composite, the size of the surface wrinkles is customized and controlled. This allows incident light to efficiently emit and radiate sunlight within the wrinkled structure, combining with the interfacial chemical composition, thus improving the surface's radiative cooling efficiency. Simultaneously, the heat transfer path is optimized by incorporating a three-dimensional gradient thermal conductivity network within the coating. The coating can rapidly cool its surface under sunlight, achieving rapid active heat conduction / dissipation, while also providing corrosion resistance.

[0167] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A corrosion-resistant and cooling coating, characterized in that, The components include the following parts by weight: 1-20 parts of composite nano-functional filler, 1-20 parts of photosensitive polydimethylsiloxane-lipoic acid composite and 23-230 parts of organosilicon polyurethane matrix; The composite nanofunctional filler comprises the following components in parts by weight: 1-100 parts of metal particles, 1-100 parts of dispersant, 100-1000 parts of solvent α, and 1-100 parts of inorganic filler. The photosensitive polydimethylsiloxane-lipoic acid composite comprises the following components in parts by weight: 10-100 parts of hydroxypropyl-terminated polydimethylsiloxane, 10-100 parts of lipoic acid, 10-100 parts of 4-dimethylaminopyridine, 10-100 parts of dehydrating agent, and 100-1000 parts of solvent β. The organosilicon polyurethane body comprises the following components in parts by weight: 10-100 parts of dimethylsiloxane with dual-terminated groups, 1-10 parts of polyisocyanate, 1-10 parts of polyamine or polyol, 1-10 parts of diamino / hydroxyl disulfide compound, and 10-100 parts of solvent β. The preparation method of the photosensitive polydimethylsiloxane-lipoic acid complex is as follows: hydroxypropyl-terminated polydimethylsiloxane, lipoic acid, 4-dimethylaminopyridine, dehydrating agent and solvent β are mixed and stirred at 20~60℃ for 10~24h to obtain the photosensitive polydimethylsiloxane-lipoic acid complex. The preparation method of the organosilicon polyurethane body is as follows: a double-terminated polydimethylsiloxane, a polyisocyanate and solvent β are mixed and reacted at an inert atmosphere and 60-80°C for 1-4 hours to obtain an isocyanate-terminated prepolymer; a diamino / hydroxyl disulfide compound, a polyamine or a polyol are added to the isocyanate-terminated prepolymer and reacted at an inert atmosphere and 60-80°C for 1-4 hours to obtain the organosilicon polyurethane body; The diamino / hydroxy disulfide compounds include one or more of 4,4'-diaminodiphenyl disulfide, bis(4-hydroxyphenyl) disulfide, 2,2'-diaminodiphenyl disulfide, bis(2-hydroxyethyl) disulfide and 3,3'-dihydroxydiphenyl disulfide; The metal particles include one or more of zinc powder, aluminum powder, copper powder, silver powder, stainless steel powder, nickel powder, titanium powder, molybdenum powder, and tin powder; The inorganic filler includes one or more of boron nitride, silicon carbide, aluminum oxide, titanium dioxide, barium sulfate, ferrous oxide, copper oxide, zinc oxide, zirconium oxide, lead carbonate, magnesium carbonate, magnesium oxide, calcium carbonate, and silicon dioxide.

2. The anti-corrosion and cooling coating according to claim 1, characterized in that, The dispersant includes one or more of BYK-110, BYK-2080, EFKA-4010, sodium polycarboxylate, aminopropyltrimethoxysilane, aminopropyltriethoxysilane, and sodium dodecylbenzenesulfonate.

3. The anti-corrosion and cooling coating according to claim 1, characterized in that, The weight-average molecular weight of the hydroxypropyl-terminated polydimethylsiloxane is 1000 to 10000.

4. The anti-corrosion and cooling coating according to claim 1, characterized in that, The dehydrating agent includes one or more of trifluoromethylbenzoic anhydride, anhydrous aluminum sulfate, and N,N'-dicyclohexylcarbodiimide.

5. The anti-corrosion and cooling coating according to claim 1, characterized in that, The solvent α includes one or more of water, methanol, ethanol, xylene, ethyl acetate, tetrahydrofuran, acetone, and dichloromethane; The solvent β includes one or more of tetrahydrofuran, acetone, dichloromethane, xylene, N,N-dimethylformamide, ethyl acetate, and butyl acetate.

6. The anti-corrosion and cooling coating according to claim 1, characterized in that, The weight-average molecular weight of the dimethylsiloxane is 1,000 to 10,000, and the diterminal groups in its molecular formula are one or more of hydroxypropyl, aminopropyl, and epoxy groups.

7. The anti-corrosion and cooling coating according to claim 1, characterized in that, The polyisocyanates include diisocyanates or triisocyanates.

8. The anti-corrosion and cooling coating according to claim 1, characterized in that, The polyol includes one or both of glycerol and butanediol; the polyamine includes one or both of triethylamine and hexamethylenediamine.

9. The method for preparing the anti-corrosion and cooling coating according to any one of claims 1 to 8, characterized in that, Includes the following steps: Metal particles, dispersant, solvent α and inorganic filler are mixed and stirred at 0-40℃ for 10-24h to obtain composite nanofunctional filler; Hydroxypropyl-terminated polydimethylsiloxane, thioctic acid, 4-dimethylaminopyridine, dehydrating agent and solvent β were mixed and stirred at 20-60°C for 10-24 h to obtain a photosensitive polydimethylsiloxane-thioctic acid complex. A double-terminated polydimethylsiloxane, a polyisocyanate, and a solvent β are mixed and reacted under an inert atmosphere and at 60–80°C for 1–4 h to obtain an isocyanate-terminated prepolymer. A diamino / hydroxyl disulfide compound, a polyamine, or a polyol is added to the isocyanate-terminated prepolymer and reacted under an inert atmosphere and at 60–80°C for 1–4 h to obtain an organosilicon polyurethane matrix. The anti-corrosion and cooling coating is obtained by mixing the composite nano-functional filler, the photosensitive polydimethylsiloxane-thioctic acid composite and the organosilicon polyurethane matrix.

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