Water-based long-acting non-residual antioxidant and preparation method thereof

Abstract

This invention relates to the field of metal surface treatment agents, and discloses a water-based long-lasting, residue-free antioxidant and its preparation method. The antioxidant, by mass percentage, comprises the following components: 4%–10% of a mild reactive corrosion inhibitor, 1%–5% of a supramolecular self-assembly passivating agent, 0.5%–2% of a vapor-phase corrosion inhibitor, 0.5%–3% of self-healing microcapsules, 1%–5% of a reducing agent, 0.1%–1% of a fluorocarbon surfactant, 0.5%–2% of a water quality stabilizer and a pH adjuster. An appropriate amount of the pH adjuster is used to adjust the system pH to 8.5–9.5, and the remainder is deionized water. This invention results in a long-lasting antioxidant protection period, leaves no residue after drying, and is environmentally friendly.

Description

Technical Field

[0001] This invention relates to the field of metal surface treatment agents, and in particular to a water-based long-lasting, residue-free antioxidant and its preparation method. Background Technology

[0002] After machining, non-ferrous metals such as aluminum alloys and copper alloys are prone to oxidation, discoloration, and corrosion in the air, especially under high temperature and humidity conditions. This leads to a decrease in the surface finish of the workpiece, and in severe cases, even scrapping the workpiece, causing economic losses to the manufacturing company. Currently, the industry commonly uses rust-preventive oils or traditional rust inhibitors for protection. These products often form an oil film or visible chemical film on the metal surface, affecting the appearance of the workpiece. Furthermore, they require additional cleaning steps before subsequent processes, increasing costs and environmental pollution.

[0003] In existing technologies, some antioxidants used in the food industry or oil-phase antioxidants used in the lubricating oil industry cannot be directly applied to the field of water-based metal treatment. The former has a single function and cannot meet the requirements of long-term corrosion protection in industrial environments; the latter is oil-soluble and incompatible with water-based systems. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a water-based long-lasting, residue-free antioxidant and its preparation method, so that the antioxidant has a long protection period and leaves no residue after drying.

[0005] The present invention solves the above-mentioned technical problems through the following technical means:

[0006] In a first aspect, this invention discloses a water-based, long-lasting, residue-free antioxidant, comprising the following components by mass percentage: 4%~10% of a mild reactive corrosion inhibitor, 1%~5% of a supramolecular self-assembly passivating agent, 0.5%~2% of a vapor-phase corrosion inhibitor, 0.5%~3% of a self-healing microcapsule, 1%~5% of a reducing agent, 0.1%~1% of a fluorocarbon surfactant, 0.5%~2% of a water quality stabilizer and a pH adjuster, wherein an appropriate amount of the pH adjuster is used to adjust the pH value of the system to 8.5-9.5, and the remainder is deionized water.

[0007] Furthermore, the mild reactive corrosion inhibitor is carboxybenzotriazole or glutamic acid; the supramolecular self-assembly passivating agent is a fluorocarbon-based or siloxane-based amphiphilic molecule; and the gas phase corrosion inhibitor is thiobenzothiazole or nitrobenzazole.

[0008] Furthermore, the wall material of the self-healing microcapsules is urea-formaldehyde resin or a gelatin-gum arabic composite, and the contents of the self-healing microcapsules are amphiphilic molecules based on fluorocarbons or siloxanes. The self-healing microcapsules are used to release and achieve self-repair when the membrane is damaged.

[0009] Furthermore, the fluorocarbon surfactant is a perfluoroalkyl carboxylate or a perfluoroalkyl sulfonate. In this technical solution, the fluorocarbon surfactant has extremely low surface tension, which can significantly reduce the surface tension of the drug solution, allowing it to quickly wet the complex structure of the metal surface and even penetrate into the micropores, expelling air and ensuring uniform coverage of the antioxidant components. Simultaneously, due to its extremely small dosage and easy volatilization or decomposition during the drying process, it works synergistically with other low-residue components in the formulation to ensure minimal visible residues such as inorganic salts or polymers after drying, achieving a residue-free visual effect.

[0010] Furthermore, the reducing agent is one of hydrazine hydrate, sodium isoascorbate, and sodium bisulfite.

[0011] Furthermore, the water quality stabilizer is disodium ethylenediaminetetraacetate or aminotrimethylphosphonic acid; the pH adjuster is an organic amine. The reducing agent continuously consumes any dissolved oxygen in the system, maintaining a reducing environment and assisting the main antioxidant in its function. In this technical solution, the water quality stabilizer can complex calcium, magnesium, and other metal ions in the water, preventing them from forming insoluble substances that affect transparency and stability, and stabilizing the antioxidant components. Organic amine pH adjusters not only provide a suitable alkaline environment to inhibit acid corrosion, but also have vapor-phase corrosion inhibition effects and can produce synergistic effects with certain antioxidants.

[0012] Furthermore, by weight percentage, it also includes 0.5% to 3% of a UV-protective antioxidant; the UV-protective antioxidant is resorcinol benzoate or benzotriazole UV absorber. In this technical solution, the added UV-protective antioxidant can effectively absorb ultraviolet light in the environment, prevent the oxidation reaction on the metal surface caused by ultraviolet photocatalysis, and solve the problem of easy discoloration of metals in outdoor or light-exposed environments, which is a function that traditional antioxidants do not possess.

[0013] Secondly, this invention discloses a method for preparing the above-mentioned water-based long-lasting, residue-free antioxidant, comprising the following steps:

[0014] S1. Dissolve mild reactive corrosion inhibitor, supramolecular self-assembly passivator, vapor phase corrosion inhibitor and pH adjuster in deionized water to form a base solution;

[0015] S2. Add the self-healing microcapsules, reducing agent, fluorocarbon surfactant, water quality stabilizer and UV-protective antioxidant to the base solution obtained in step S1 under low-speed stirring, and disperse evenly.

[0016] S3. Add pH adjuster and deionized water, mix well to bring the pH to 8.5-9.5, and then let it stand to age to obtain antioxidant.

[0017] Furthermore, the preparation method of the self-healing microcapsules in step S2 includes the following steps:

[0018] S201. Take 5-10 parts by weight of fluorocarbon-based amphiphilic molecules (such as perfluorooctanoic acid) or siloxane-based amphiphilic molecules (such as polydimethylsiloxane-polyoxyethylene copolymer), add 50-100 parts by weight of organic solvent (such as ethanol or acetone), stir at 40-50℃ for 30-50 minutes until completely dissolved, and obtain the contents.

[0019] S202, take 10-12 parts by weight of urea and 15-20 parts by weight of formaldehyde solution (37%), add 50-60 parts by weight of deionized water, adjust the pH to 8.0-9.0 with ammonia water, stir and react at 60-70℃ for 1-2 hours to form a transparent prepolymer solution; the reaction endpoint is determined by the solution viscosity reaching 50-100 cP, to obtain the wall material solution;

[0020] S203. Slowly add the contents solution obtained in step S201 dropwise to the wall material solution in step S202. Add 0.1-0.5% (by mass) of emulsifier (such as Span 80) to stabilize the emulsion. Stir at 500-1000 rpm for 30-60 minutes at 40-60℃ to obtain the emulsion. The emulsion particle size is controlled by the stirring speed: 500 rpm corresponds to a particle size of 5-10 μm, and 1000 rpm corresponds to a particle size of 1-5 μm. The emulsification endpoint is determined by the emulsion being homogeneous and without oil phase separation.

[0021] S204. Transfer the emulsion to a water bath at 70-80℃ and heat for 2-3 hours to allow the urea-formaldehyde resin to crosslink and cure. Then slowly cool to room temperature to obtain microcapsules.

[0022] S205. Wash the microcapsules 3-5 times with deionized water to remove unencapsulated contents and emulsifiers; dry them in a vacuum drying oven at 40-50℃ for 4-6 hours until constant weight (moisture content <5%); collect the microcapsules with a particle size of 1-10 μm by sieving, and store them in a sealed container at 4℃ in a light-protected environment.

[0023] This technical solution ensures the high performance of self-healing microcapsules through precise control of emulsification, curing, and parameter optimization. In synergy with the antioxidant system of this patent, such as mild reactive corrosion inhibitors and supramolecular self-assembly passivators, it can strengthen the chemical anchoring + physical barrier mechanism, thereby improving overall antioxidant efficiency.

[0024] Furthermore, the mass ratio of the contents to the wall material is 1:(2-3).

[0025] In summary, this application has the following beneficial effects:

[0026] 1. In this invention, firstly, a mild reactive corrosion inhibitor rapidly forms an extremely thin and uniform initial anchoring layer on the metal surface. This process is mild, avoiding the uneven attack on the heterogeneous metal surface by strong ligands. Subsequently, a supramolecular self-assembling passivator uses this anchoring layer as a template to perform highly ordered self-assembly through intermolecular forces, forming a dense, stable, and superhydrophobic physical barrier film. This chemical anchoring + physical assembly mode utilizes both the robustness of chemical film formation and the integrity and safety of the physical barrier, achieving a good synergistic protective effect.

[0027] 2. The microcapsules of the present invention provide dynamic protection capabilities. When the main barrier layer is damaged due to accidental scratches or other reasons, the microcapsules respond in time and release a self-healing agent that can quickly fill the damaged area and restore the integrity of the barrier. In this way, the protection life is greatly extended, which is a creative design for the long-term protection needs.

[0028] 3. The entire system design of this invention aims to form a protective film with molecular-level thickness. The supramolecular layer itself has extremely low surface energy and leaves no visible residue after drying. More importantly, by avoiding strong and uncontrollable chemical coordination reactions, this solution is particularly suitable for high-precision workpieces with stringent requirements for surface integrity, achieving true non-destructive protection. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1

[0031] This embodiment describes a method for preparing self-healing microcapsules, which includes the following steps:

[0032] A1. Take 5 kg of perfluorooctanoic acid, add 50 kg of organic solvent ethanol, and stir at 40°C for 30 minutes until completely dissolved to obtain the contents;

[0033] A2. Take 10 kg of urea and 15 kg of 37% formaldehyde solution, add 50 kg of deionized water, adjust the pH to 8.0 with ammonia water, stir and react at 60℃ for 1 hour to form a transparent prepolymer solution, and obtain the wall material solution.

[0034] A3. Slowly add the obtained content solution dropwise to the wall material solution, wherein the mass ratio of content to wall material is 1:2. Then add 0.1% of the total mass of emulsifier Span 80 to stabilize the emulsion. Stir at 500 rpm for 30 minutes at 40°C to obtain the emulsion.

[0035] A4. Transfer the emulsion to a 70°C water bath and heat for 2 hours to allow the urea-formaldehyde resin to crosslink and solidify. Then slowly cool to room temperature to obtain microcapsules.

[0036] A5. Wash the microcapsules three times with deionized water to remove unencapsulated contents and emulsifiers; dry them in a vacuum drying oven at 40℃ for 4 hours until constant weight, with a moisture content of <5%; collect the microcapsules with a particle size of 1-10 μm by sieving, and store them in a sealed container at 4℃ in a light-protected environment.

[0037] Example 2

[0038] This embodiment describes a method for preparing self-healing microcapsules, which includes the following steps:

[0039] A1. Take 7.5 kg of polydimethylsiloxane-polyoxyethylene copolymer, add 75 kg of organic solvent acetone, and stir at 45°C for 40 minutes until completely dissolved to obtain the contents;

[0040] A2. Take 11 kg of urea and 17.5 kg of 37% formaldehyde solution, add 55 kg of deionized water, adjust the pH to 8.5 with ammonia water, stir and react at 65℃ for 1.5 hours to form a transparent prepolymer solution, and obtain the wall material solution.

[0041] A3. Slowly add the obtained content solution dropwise to the wall material solution, wherein the mass ratio of content to wall material is 1:2.5. Then add 0.3% of the total mass of emulsifier Span 80 to stabilize the emulsion. Stir at 750 rpm for 45 minutes at 50°C to obtain the emulsion.

[0042] A4. Transfer the emulsion to a 75°C water bath and heat for 2.5 hours to allow the urea-formaldehyde resin to crosslink and cure. Then slowly cool to room temperature to obtain microcapsules.

[0043] A5. Wash the microcapsules four times with deionized water to remove unencapsulated contents and emulsifiers; dry them in a vacuum drying oven at 45℃ for 5 hours until constant weight, with a moisture content of <5%; collect the microcapsules with a particle size of 1-10 μm by sieving, and store them in a sealed container at 4℃ in a light-protected environment.

[0044] Example 3

[0045] This embodiment describes a method for preparing self-healing microcapsules, which includes the following steps:

[0046] A1. Take 10 kg of perfluorooctanoic acid, add 100 kg of organic solvent ethanol, stir at 50°C for 50 minutes until completely dissolved, and obtain the contents;

[0047] A2. Take 12 kg of urea and 20 kg of 37% formaldehyde solution, add 60 kg of deionized water, adjust the pH to 9.0 with ammonia water, stir and react at 70℃ for 2 hours to form a transparent prepolymer solution, and obtain the wall material solution.

[0048] A3. Slowly add the obtained content solution dropwise to the wall material solution, wherein the mass ratio of content to wall material is 1:3. Then add 0.5% of the total mass of emulsifier Span 80 to stabilize the emulsion. Stir at 1000 rpm for 60 minutes at 60°C to obtain the emulsion.

[0049] A4. Transfer the emulsion to an 80°C water bath and heat for 3 hours to allow the urea-formaldehyde resin to crosslink and solidify. Then slowly cool to room temperature to obtain microcapsules.

[0050] A5. Wash the microcapsules 5 times with deionized water to remove unencapsulated contents and emulsifiers; dry them in a vacuum drying oven at 50℃ for 6 hours until constant weight, with a moisture content of <5%; collect the microcapsules with a particle size of 1-10 μm by sieving, and store them in a sealed container at 4℃ in a light-protected environment.

[0051] Example 4

[0052] This embodiment describes a method for preparing a water-based, long-lasting, residue-free antioxidant.

[0053] In this embodiment, the mild reactive corrosion inhibitor (carboxybenzotriazole): 7%

[0054] Supramolecular self-assembly passivating agent (fluorocarbon-based amphiphilic molecule produced by Shanghai Yumu Chemical): 3%

[0055] Vapor phase corrosion inhibitor (thiobenzothiazole): 1.25%

[0056] Self-healing microcapsules (prepared in Example 1): 1.75%

[0057] Reducing agent (sodium isoascorbate): 3%

[0058] Fluorocarbon surfactant (potassium perfluorooctyl sulfonate): 0.55%

[0059] Water quality stabilizer (disodium ethylenediaminetetraacetate): 1.25%

[0060] pH adjuster (diethanolamine): Appropriate amount (for adjusting pH)

[0061] UV-protective antioxidant (resorcinol benzoate): 1.75%

[0062] Deionized water: Balance (replenish to 100%)

[0063] The final pH of the system was adjusted to 9.0.

[0064] The preparation method includes the following steps:

[0065] Carboxybenzotriazole, fluorocarbon amphiphilic molecules, thiobenzothiazole, and a portion of diethanolamine were dissolved in approximately 70% of the total volume of deionized water and stirred until completely dissolved to form a base solution. Under low-speed stirring, the self-healing microcapsules, sodium isoascorbate, potassium perfluorooctyl sulfonate, disodium ethylenediaminetetraacetate, and resorcinol benzoate were sequentially added to the base solution and dispersed evenly. Finally, the remaining deionized water and diethanolamine were added, the pH was adjusted to 9.0, and the mixture was allowed to stand for 24 hours to obtain the product.

[0066] Example 5

[0067] This embodiment represents a second method for preparing a water-based, long-lasting, residue-free antioxidant.

[0068] In this embodiment, the mild reactive corrosion inhibitor (glutamic acid) is 10%.

[0069] Supramolecular self-assembly passivating agent (siloxane-based amphiphilic molecule produced by Xi'an Qiyue Biotechnology Co., Ltd.): 5%

[0070] Vapor phase corrosion inhibitor (nitrobenzazole): 2%

[0071] Self-healing microcapsules (prepared in Example 2): 3%

[0072] Reducing agent (hydrazine hydrate, 100%): 5%

[0073] Fluorocarbon surfactant (sodium perfluorononylcarboxylate): 1%

[0074] Water quality stabilizer (aminotrimethylphosphonic acid): 2%

[0075] pH adjuster (diethanolamine): appropriate amount

[0076] UV-protective antioxidant (benzotriazole): 3%

[0077] Deionized water: Balance

[0078] The final pH of the system was adjusted to 9.5.

[0079] The preparation method includes the following steps:

[0080] Glutamic acid, siloxane-based amphiphilic molecules, nitrobenzazole, and a portion of diethanolamine were dissolved in approximately 70% of the total volume of deionized water and stirred until completely dissolved to form a base solution. Under low-speed stirring, the self-healing microcapsules, reducing agent, fluorocarbon surfactant, water stabilizer, and UV-protective antioxidant were sequentially added to the base solution and dispersed evenly. Finally, the remaining deionized water and diethanolamine were added, the pH was adjusted to 9.5, and the mixture was allowed to stand for 24 hours to obtain the product.

[0081] Example 6

[0082] This embodiment describes the third method for preparing a water-based, long-lasting, residue-free antioxidant.

[0083] In this embodiment, the mild reactive corrosion inhibitor (glutamic acid) is 4%.

[0084] Supramolecular self-assembly passivating agent (siloxane-based amphiphilic molecule produced by Xi'an Qiyue Biotechnology Co., Ltd.): 1%

[0085] Vapor phase corrosion inhibitor (nitrobenzazole): 0.5%

[0086] Self-healing microcapsules (prepared in Example 3): 0.5%

[0087] Reducing agent (hydrazine hydrate, 100%): 1%

[0088] Fluorocarbon surfactant (sodium perfluorononylcarboxylate): 0.1%

[0089] Water quality stabilizer (aminotrimethylphosphonic acid): 0.5%

[0090] pH adjuster (diethanolamine): appropriate amount

[0091] UV-protective antioxidant (benzotriazole): 0.5%

[0092] Deionized water: Balance

[0093] The final pH of the system was adjusted to 8.5.

[0094] The preparation method includes the following steps:

[0095] Glutamic acid, siloxane-based amphiphilic molecules, nitrobenzazole, and a portion of diethanolamine were dissolved in approximately 70% of the total volume of deionized water and stirred until completely dissolved to form a base solution. Under low-speed stirring, the self-healing microcapsules, reducing agent, fluorocarbon surfactant, water stabilizer, and UV-protective antioxidant were sequentially added to the base solution and dispersed evenly. Finally, the remaining deionized water and diethanolamine were added, the pH was adjusted to 8.5, and the mixture was allowed to stand for 24 hours to obtain the product.

[0096] Example 7

[0097] This embodiment is the fourth method for preparing a water-based, long-lasting, residue-free antioxidant. The only difference between this embodiment and Embodiment 6 is that self-healing microcapsules are not added in this embodiment. Specifically:

[0098] In this embodiment, the mild reactive corrosion inhibitor (glutamic acid) is 4%.

[0099] Supramolecular self-assembly passivating agent (siloxane-based amphiphilic molecule produced by Xi'an Qiyue Biotechnology Co., Ltd.): 1%

[0100] Vapor phase corrosion inhibitor (nitrobenzazole): 0.5%

[0101] Reducing agent (hydrazine hydrate, 100%): 1%

[0102] Fluorocarbon surfactant (sodium perfluorononylcarboxylate): 0.1%

[0103] Water quality stabilizer (aminotrimethylphosphonic acid): 0.5%

[0104] pH adjuster (diethanolamine): appropriate amount

[0105] UV-protective antioxidant (benzotriazole): 0.5%

[0106] Deionized water: Balance

[0107] The final pH of the system was adjusted to 8.5.

[0108] The preparation method includes the following steps:

[0109] Glutamic acid, siloxane-based amphiphilic molecules, nitrobenzazole, and a portion of diethanolamine were dissolved in approximately 70% of the total volume of deionized water and stirred until completely dissolved to form a base solution. Under low-speed stirring, the aforementioned reducing agent, fluorocarbon surfactant, water stabilizer, and UV-protective antioxidant were sequentially added to the base solution and dispersed evenly. Finally, the remaining deionized water and diethanolamine were added, the pH was adjusted to 8.5, and the mixture was allowed to stand for 24 hours to obtain the product.

[0110] The following are the results of technical performance testing of the antioxidants prepared in Examples 4-7:

[0111]

[0112] Based on the above analysis of Examples 4-7, it can be seen that:

[0113] 1. Examples 4, 5, and 6 represent specific implementations of the present application's solution at different ratios (high, medium, and low concentrations). Test results show that they all meet all requirements from basic physicochemical properties (such as appearance, pH, surface tension, and no residue) to corrosion protection performance (immersion test, electrochemical test), ultimately achieving the core long-term goal of "observation for more than one year." This fully demonstrates the effectiveness and reliability of the present technical solution.

[0114] 2. Example 7 serves as a comparative example. The results show that although its short-term protection and basic performance may meet the standards, its long-term protection capability (observed for more than 1 year) is significantly weaker than that of Examples 4-6. The self-healing microcapsules solve the problem that traditional protective coatings fail once damaged.

[0115] 3. Examples 4, 5, and 6 demonstrate that products suitable for different protection levels and cost requirements can be formulated. This indicates that the scope of protection of this application is fully supported by multiple embodiments, and the technical solution has good flexibility for industrial application.

[0116] In summary, the technical solution provided in this patent application, through a multi-synergistic mechanism of initial anchoring with a mild reactive corrosion inhibitor, construction of a dense barrier through supramolecular self-assembly, and long-term maintenance through self-healing microcapsules, has successfully developed a water-based antioxidant that meets the two core requirements of long-term effectiveness (>1 year) and no residue (solid content ≤100 ppm). This effectively solves the problem of oxidation and discoloration after machining of non-ferrous metals and has significant technological progress and practical value.

[0117] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention. Technical aspects, shapes, and structures not described in detail in this invention are all well-known technologies.

Claims

1. A water-based, long-lasting, residue-free antioxidant, characterized in that, By mass percentage, it includes the following components: 4%–10% mild reactive corrosion inhibitor, 1%–5% supramolecular self-assembly passivating agent, 0.5%–2% vapor phase corrosion inhibitor, 0.5%–3% self-healing microcapsules, 1%–5% reducing agent, 0.1%–1% fluorocarbon surfactant, 0.5%–2% water quality stabilizer and pH adjuster. The pH adjuster is used to adjust the pH value of the system to 8.5–9.5, and the balance is deionized water.

2. The water-based long-lasting, residue-free antioxidant according to claim 1, characterized in that, The mild reactive corrosion inhibitor is carboxybenzotriazole or glutamic acid; the supramolecular self-assembly passivating agent is a fluorocarbon-based or siloxane-based amphiphilic molecule; the gas phase corrosion inhibitor is thiobenzothiazole or nitrobenzazole.

3. The water-based long-lasting, residue-free antioxidant according to claim 1, characterized in that, The wall material of the self-healing microcapsule is urea-formaldehyde resin or gelatin-gum arabic composite, and the contents of the self-healing microcapsule are amphiphilic molecules based on fluorocarbons or siloxanes.

4. The water-based long-lasting, residue-free antioxidant according to claim 1, characterized in that, The fluorocarbon surfactant is a perfluoroalkyl carboxylate or a perfluoroalkyl sulfonate.

5. The water-based long-lasting, residue-free antioxidant according to claim 1, characterized in that, The reducing agent is one of hydrazine hydrate, sodium isoascorbate, and sodium bisulfite.

6. The water-based long-lasting, residue-free antioxidant according to claim 1, characterized in that, The water quality stabilizer is disodium ethylenediaminetetraacetate or aminotrimethylphosphonic acid; the pH adjuster is an organic amine.

7. A water-based, long-lasting, residue-free antioxidant according to any one of claims 1-6, characterized in that, By weight percentage, it also includes 0.5% to 3% of UV-protective antioxidants; the UV-protective antioxidants are resorcinol benzoate or benzotriazole UV absorbers.

8. A method for preparing a water-based, long-lasting, residue-free antioxidant, wherein the antioxidant as described in claim 7 is prepared, characterized in that... Includes the following steps: S1. Dissolve mild reactive corrosion inhibitor, supramolecular self-assembly passivator, vapor phase corrosion inhibitor and pH adjuster in deionized water to form a base solution; S2. Add the self-healing microcapsules, reducing agent, fluorocarbon surfactant, water quality stabilizer and UV-protective antioxidant to the base solution obtained in step S1 under low-speed stirring, and disperse evenly. S3. Add pH adjuster and deionized water, mix well to bring the pH to 8.5-9.5, and then let it stand to age to obtain antioxidant.

9. The method for preparing a water-based long-lasting, residue-free antioxidant according to claim 8, characterized in that, The method for preparing the self-healing microcapsules in step S2 includes the following steps: S201. Take 5-10 parts by mass of fluorocarbon-based amphiphilic molecules or siloxane-based amphiphilic molecules, add 50-100 parts by mass of organic solvent, stir at 40-50℃ for 30-50 minutes until completely dissolved, and obtain the contents. S202, take 10-12 parts by weight of urea and 15-20 parts by weight of formaldehyde solution, add 50-60 parts by weight of deionized water, adjust the pH to 8.0-9.0 with ammonia water, stir and react at 60-70℃ for 1-2 hours to form a transparent prepolymer solution, and obtain the wall material solution; S203. Slowly add the contents solution obtained in step S201 to the wall material solution in step S202, add 0.1-0.5% of the total mass of emulsifier, and stir at 500-1000 rpm for 30-60 minutes at 40-60℃ to obtain an emulsion; S204. Transfer the emulsion to a water bath at 70-80℃ and heat for 2-3 hours to allow the urea-formaldehyde resin to crosslink and cure. Then slowly cool it to room temperature to obtain microcapsules. S205. Wash the microcapsules 3-5 times with deionized water; dry them in a vacuum drying oven at 40-50℃ for 4-6 hours until the moisture content is <5%; collect the microcapsules with a particle size of 1-10 μm by sieving.

10. The method for preparing a water-based, long-lasting, residue-free antioxidant according to claim 9, characterized in that, The mass ratio of the contents to the wall material is 1:(2-3).

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