An aqueous anti-flash rust and salt spray resistant additive and its preparation method

Abstract

This application relates to the technical field of coating additives, and specifically discloses an aqueous anti-flash rust and salt spray resistant additive and its preparation method. An aqueous anti-flash rust and salt spray resistant additive, the raw materials of which include 50-65 parts of sodium ethylene diamine tetra(methylene phosphonate), 60-70 parts of N,N-dimethyldodecylamine, 20-40 parts of polydimethylsiloxane, 20-30 parts of nano calcium carbonate, 25-40 parts of a modified rare earth salt solution, and 30-50 parts of deionized water; the modified rare earth salt solution is obtained by a complexation reaction of 4-hydroxy-β-dihydrodamascenone with a rare earth salt solution. The aqueous anti-flash rust and salt spray resistant additive of this application can effectively improve the anti-flash rust performance of the additive under high temperature conditions by adopting a modified rare earth salt solution and a ferrous sulfate-zinc powder system.

Description

Technical Field

[0001] The present application relates to the technical field of coating additives, and more specifically, to an aqueous anti-flash rust and salt spray resistant additive and a preparation method thereof. Background Art

[0002] The aqueous anti-flash rust and salt spray resistant additive is an important auxiliary agent developed to solve the flash rust phenomenon that occurs during the coating process of aqueous coatings and to improve the durability of the coatings. Flash rust is a corrosion phenomenon that occurs rapidly when metal ions are oxidized by oxygen due to an instantaneous strong electrochemical interaction between a metal substrate and an electrolyte aqueous solution in the coating during the drying process of the aqueous coating. The flash rust phenomenon will seriously affect the performance of the coating film, such as reducing the bonding ability between the coating film and the substrate, weakening the protective performance of the paint film on the metal, and affecting the appearance. In order to combat flash rust, anti-flash rust agents came into being. Anti-flash rust agents cut off or reduce the supply of oxygen by instantaneously shielding metal ions or reducing the reaction activity of metal ions, thereby weakening or aborting the electrochemical reaction. At the same time, the role of the salt spray resistant agent is to improve the corrosion resistance and anti-permeability of the coating to resist the erosion of salt spray.

[0003] In the related art, the application document with the publication number CN112961525A discloses an anti-flash rust agent for aqueous anti-corrosion coatings and a preparation method thereof. The anti-flash rust agent includes molybdate, benzoate, benzotriazole, organic alkanolamine, and deionized water. In the actual use process of the above anti-flash rust agent, especially when facing high-temperature environments in the chemical industry and metallurgy, the organic alkanolamine compound in the anti-flash rust agent is prone to oxidation, resulting in the anti-flash rust agent losing its original protective performance. And in a high-temperature environment, the electrochemical corrosion rate on the metal surface may increase, making it more difficult for the anti-flash rust agent to effectively inhibit the occurrence of corrosion. Therefore, the anti-flash rust agent in the related art has the defect of poor temperature resistance. Summary of the Invention

[0004] In order to improve the temperature resistance of the anti-flash rust agent, the present application provides an aqueous anti-flash rust and salt spray resistant additive and a preparation method thereof.

[0005] An aqueous anti-flash rust and salt spray resistant additive provided by the present application adopts the following technical solution:

[0006] An aqueous anti-flash rust and salt spray resistant additive, comprising the following raw materials in parts by weight:

[0007] Sodium ethylene diamine tetra (methylene phosphonate) 50 - 65 parts;

[0008] N,N-dimethyldodecylamine 60 - 70 parts;

[0009] Polydimethylsiloxane 20 - 40 parts;

[0010] Nano calcium carbonate 20 - 30 parts;

[0011] 25 - 40 parts of modified rare earth salt solution;

[0012] 30 - 50 parts of deionized water;

[0013] The modified rare earth salt solution is obtained by a complexation reaction of 4 - hydroxy - β - damascenone with the rare earth salt solution.

[0014] By adopting the above technical solution, the introduction of N,N - dimethyldodecylamine, with its unique quaternary ammonium salt structure, effectively neutralizes the acidic components in the coating system, fundamentally preventing the occurrence of flash rust. At the same time, this substance can also significantly improve the corrosion resistance of the coating, providing a solid anti - corrosion barrier for the additive. The addition of sodium ethylene diamine tetra (methylene phosphonate), with its strong metal surface adsorption ability and chemical cross - linking effect, significantly accelerates the film - forming speed of the coating. This characteristic not only further enhances the anti - flash rust performance of the coating, but also ensures that the coating forms a dense and uniform protective layer in a short time, effectively blocking the intrusion of external corrosive media, which is beneficial to improving the salt spray resistance of the coating.

[0015] The rare earth salt solution itself has good corrosion resistance, thus being able to enhance the anti - flash rust and salt spray resistance of the coating. Through the complexation reaction of 4 - hydroxy - β - damascenone with the rare earth salt solution, a complex with a tight structure is formed. This tight structure not only further enhances the salt spray resistance of the coating; moreover, in a high - temperature environment, organic molecules are prone to form free radicals and initiate chain reactions, leading to accelerated oxidation. The tight structure formed by 4 - hydroxy - β - damascenone and rare earth ions may have the ability to stabilize free radicals, thus slowing down the propagation speed of the chain reaction. Significantly reducing its reaction rate with oxygen. This characteristic effectively slows down the oxidation reaction of other organic substances in the additive under high - temperature conditions, thus significantly improving the high - temperature resistance of the additive.

[0016] Optionally, the modified rare earth salt solution is prepared by the following method:

[0017] A. Add 4 - hydroxy - β - damascenone to acetone and heat to dissolve to obtain solution A;

[0018] B. Adjust the pH of the rare earth salt solution to 6.5 - 7 with dilute nitric acid to obtain solution B;

[0019] C. Slowly drop solution B into solution A under magnetic stirring and stir and react at 50 - 60 °C for 4 - 5 h to obtain the modified rare earth salt solution.

[0020] Optionally, the volume ratio of 4-hydroxy-β-damascone to acetone is 1:(4 - 5); in step c, the volume ratio of solution B to solution A is 1:(0.5 - 0.8).

[0021] By adopting the above technical solution, the volume ratio of 4-hydroxy-β-damascone to acetone and the volume ratio of solution B to solution A are defined. The above reactant ratio helps to precisely control the rate of the complexation reaction and avoid a large amount of residual reactants, thereby obtaining a modified rare earth salt solution with a denser structure and more stable performance. The complex with a dense structure can further enhance the salt spray resistance of the coating and improve the high-temperature resistance of the additive.

[0022] Optionally, the rare earth salt solution is any one of Ce(NO3)3, La(NO3)3, and Pr(NO3)3.

[0023] By adopting the above technical solution, the above rare earth salt solution itself has good corrosion resistance and can significantly enhance the anti-flash rust and salt spray resistance of the coating. Through the complexation reaction, the excellent properties of rare earth elements can be further exerted to improve the overall high-temperature resistance and working stability of the additive.

[0024] Optionally, the additive raw materials further include 5 - 10 parts of ferrous sulfate solution and 5 - 8 parts of zinc powder.

[0025] By adopting the above technical solution, ferrous sulfate is acidic in aqueous solution. As a regulator, ferrous sulfate can adjust the pH value of the system to maintain the stability of the system. A stable pH value environment helps to keep the components of sodium ethylene diamine tetramethylene phosphonate and N,N-dimethyldodecylamine in the additive stable, preventing them from decomposing or failing due to too high or too low pH values, thereby enhancing the overall working stability of the additive.

[0026] As an inorganic pigment and filler, zinc powder has certain chemical stability and corrosion resistance in the coating. Its presence can further enhance the physical barrier effect of the coating, reduce the direct contact of corrosive media with the metal surface, and thus effectively improve the salt spray resistance of the additive.

[0027] Ferrous sulfate and zinc powder can form a weak electric field effect in the additive. The micro-electric field effect can significantly enhance the adsorption ability of ions or molecules in the coating on the metal surface, thereby ensuring that the coating components can adhere tightly to the metal surface. Under high-temperature conditions, as the temperature increases, the reaction rate between ferrous sulfate and zinc powder accelerates and the electric field effect enhances. Therefore, the adsorption ability and film-forming efficiency on the metal surface are effectively enhanced, thereby hindering the electrochemical corrosion of the metal substrate and the electrolyte aqueous solution in the coating, and further improving the anti-flash rust performance of the additive under high-temperature conditions.

[0028] Optionally, the concentration of the ferrous sulfate solution is 10%-20%.

[0029] By adopting the above technical solution, the concentration range of the ferrous sulfate solution helps to precisely control the pH value of the system and maintain the stability of the system, thereby ensuring that other components in the additive can fully exert their performance. A stable pH value environment is the key to improving the overall working stability of the additive.

[0030] Optionally, the average molecular weight of the polydimethylsiloxane is 5000-10000 Da.

[0031] By adopting the above technical solution, the polydimethylsiloxane within the above average molecular weight range helps to ensure good dispersibility and stability of the polydimethylsiloxane in the coating. As an excellent surfactant, polydimethylsiloxane can significantly improve the wettability and leveling property of the coating, thereby helping to form a dense and uniform protective layer and improve the salt spray resistance of the coating.

[0032] Optionally, the average particle size of the nano calcium carbonate is 20-100 nm.

[0033] By adopting the above technical solution, the average particle size range of the nano calcium carbonate is clarified. The average particle size of 20-100 nm helps to ensure good dispersibility and high specific surface area of the nano calcium carbonate in the coating. As an excellent filler, nano calcium carbonate can significantly improve the hardness and wear resistance of the coating, while enhancing the physical barrier effect of the coating and reducing the direct contact of the corrosive medium with the metal surface, thereby improving the salt spray resistance of the coating.

[0034] This application also provides a preparation method of the waterborne anti-flash rust and salt spray resistant additive, adopting the following technical solution:

[0035] A preparation method of a waterborne anti-flash rust and salt spray resistant additive includes the following steps:

[0036] S1. Mix sodium ethylene diamine tetra (methylene phosphonate), N,N-dimethyldodecylamine, the modified rare earth salt solution, the ferrous sulfate solution and deionized water at 30-50 °C and stir for 0.5-1.5 h to obtain a prefabricated solution;

[0037] S2. After mixing polydimethylsiloxane, nano calcium carbonate, zinc powder with the prefabricated solution, stir for 0.5-1.5 h, and then perform ultrasonic treatment for 0.5-1.5 h to obtain the waterborne anti-flash rust and salt spray resistant additive.

[0038] In summary, this application has the following beneficial effects:

[0039] 1. Since this application uses a modified rare earth salt solution, the rare earth salt solution itself has good corrosion resistance, which can enhance the anti-flash rust and salt spray resistance of the paint coating. Through the complexation reaction of 4-hydroxy-β-dihydrodamascenone and the rare earth salt solution, a complex with a compact structure is formed. This compact structure not only further enhances the salt spray resistance of the paint; moreover, in a high-temperature environment, organic molecules are prone to form free radicals and initiate chain reactions, leading to accelerated oxidation. The compact structure formed by 4-hydroxy-β-dihydrodamascenone and rare earth ions has the ability to stabilize free radicals to a certain extent, thus slowing down the propagation speed of the chain reaction. Significantly reducing its reaction rate with oxygen. This property effectively slows down the oxidation reaction of other organic substances in the additive under high-temperature conditions, thus significantly improving the high-temperature resistance of the additive.

[0040] 2. The raw materials of this application also include ferrous sulfate and zinc powder. Ferrous sulfate is acidic in aqueous solution. As a regulator, ferrous sulfate can adjust the pH value of the system to maintain the stability of the system. A stable pH value environment helps to keep the components of sodium ethylene diamine tetra (methylene phosphonate) and N,N-dimethyldodecylamine in the additive stable, preventing them from decomposing or failing due to too high or too low pH value, thereby enhancing the overall working stability of the additive. Zinc powder, as an inorganic pigment and filler, has certain chemical stability and corrosion resistance in the paint. Its presence can further enhance the physical barrier effect of the coating, reducing the direct contact of corrosive media with the metal surface, thus effectively improving the salt spray resistance of the additive. A weak electric field effect can be formed between ferrous sulfate and zinc powder in the additive. The micro-electric field effect can significantly enhance the adsorption ability of ions or molecules in the paint on the metal surface, thereby ensuring that the paint components can adhere tightly to the metal surface. Under high-temperature conditions, as the temperature increases, the reaction rate between ferrous sulfate and zinc powder accelerates, and the electric field effect enhances. Therefore, the adsorption ability and film-forming efficiency on the metal surface are effectively enhanced, thereby hindering the electrochemical corrosion of the metal substrate and the electrolyte aqueous solution in the paint, and further improving the anti-flash rust performance of the additive under high-temperature conditions. Detailed implementation mode

[0041] The following further elaborates on this application with reference to examples.

[0042] Preparation example of modified rare earth salt solution

[0043] Preparation example 1

[0044] The modified rare earth salt solution is prepared by the following method:

[0045] A. Add 1 L of 4-hydroxy-β-dihydrodamascenone to 4 L of acetone and heat to 45 °C for dissolution to obtain solution A;

[0046] B. Adjust the pH of the Ce(NO3)3 solution to 6.5 with dilute nitric acid having a mass concentration of 10% to obtain solution B. The initial mass concentration of the Ce(NO3)3 solution is 5%.

[0047] C. Slowly drop 1 L of solution B into 0.5 L of solution A under magnetic stirring, and stir and react for 4 h at 50 °C to obtain a modified rare earth salt solution.

[0048] Preparation Example 2

[0049] The modified rare earth salt solution is prepared by the following method:

[0050] A. Add 1 L of 4-hydroxy-β-dihydrodamascone to 4.5 L of acetone, and heat to 45 °C for dissolution to obtain solution A;

[0051] B. Adjust the pH of the Ce(NO3)3 solution to 6.5 with dilute nitric acid having a mass concentration of 10% to obtain solution B. The initial mass concentration of the Ce(NO3)3 solution is 5%;

[0052] C. Slowly drop 1 L of solution B into 0.7 L of solution A under magnetic stirring, and stir and react for 4.5 h at 55 °C to obtain a modified rare earth salt solution.

[0053] Preparation Example 3

[0054] The modified rare earth salt solution is prepared by the following method:

[0055] A. Add 1 L of 4-hydroxy-β-dihydrodamascone to 5 L of acetone, and heat to 45 °C for dissolution to obtain solution A;

[0056] B. Adjust the pH of the Ce(NO3)3 solution to 7 with dilute nitric acid having a mass concentration of 10% to obtain solution B. The initial mass concentration of the Ce(NO3)3 solution is 5%;

[0057] C. Slowly drop 1 L of solution B into 0.8 L of solution A under magnetic stirring, and stir and react for 5 h at 60 °C to obtain a modified rare earth salt solution.

[0058] Preparation Example 4

[0059] The modified rare earth salt solution is different from that of Preparation Example 3 in that: in step b, the rare earth salt solution is La(NO3)3 with a mass concentration of 5%.

[0060] Preparation Example 5

[0061] The modified rare earth salt solution is different from that of Preparation Example 3 in that: in step b, the rare earth salt solution is Pr(NO3)3 with a mass concentration of 5%.

[0062] Preparation Example 6

[0063] The modified rare earth salt solution, different from Preparation Example 3 in that: 4-hydroxy-β-damascone in step a is replaced by ethylenediaminetetraacetic acid.

[0064] Examples

[0065] Example 1

[0066] An aqueous anti-flash rust and salt spray resistant additive, the raw material components and dosages thereof are shown in Table 1. Among them, the average molecular weight of polydimethylsiloxane is 5000 Da; the average particle size of nano calcium carbonate is 20 nm; the modified rare earth salt solution is the modified rare earth salt solution prepared in Preparation Example 1.

[0067] A preparation method of an aqueous anti-flash rust and salt spray resistant additive comprises the following steps:

[0068] S1. Mix and stir sodium ethylene diamine tetramethylene phosphonate, N,N-dimethyldodecylamine, the modified rare earth salt solution and deionized water at 30 °C for 0.5 h to obtain a prefabricated solution;

[0069] S2. After mixing polydimethylsiloxane and nano calcium carbonate with the prefabricated solution, stir for 0.5 h, and then perform ultrasonic treatment for 0.5 h to obtain the aqueous anti-flash rust and salt spray resistant additive.

[0070] Example 2

[0071] An aqueous anti-flash rust and salt spray resistant additive, the raw material components and dosages thereof are shown in Table 1. Among them, the average molecular weight of polydimethylsiloxane is 7000 Da; the average particle size of nano calcium carbonate is 60 nm; the modified rare earth salt solution is the modified rare earth salt solution prepared in Preparation Example 2.

[0072] A preparation method of an aqueous anti-flash rust and salt spray resistant additive comprises the following steps:

[0073] S1. Mix and stir sodium ethylene diamine tetramethylene phosphonate, N,N-dimethyldodecylamine, the modified rare earth salt solution and deionized water at 40 °C for 1 h to obtain a prefabricated solution;

[0074] S2. After mixing polydimethylsiloxane and nano calcium carbonate with the prefabricated solution, stir for 1 h, and then perform ultrasonic treatment for 1 h to obtain the aqueous anti-flash rust and salt spray resistant additive.

[0075] Example 3

[0076] An aqueous anti-flash rust and salt spray resistant additive, the raw material components and dosages thereof are shown in Table 1. Among them, the average molecular weight of polydimethylsiloxane is 10000 Da; the average particle size of nano calcium carbonate is 100 nm; the modified rare earth salt solution is the modified rare earth salt solution prepared in Preparation Example 3.

[0077] A preparation method of an aqueous anti-flash rust and salt spray resistant additive comprises the following steps:

[0078] S1. Mix sodium ethylene diamine tetra (methylene phosphonate), N,N-dimethyldodecylamine, a modified rare earth salt solution and deionized water at 50 °C and stir for 1.5 h to obtain a prefabricated solution;

[0079] S2. Mix polydimethylsiloxane and nano calcium carbonate with the prefabricated solution, stir for 1.5 h, and then perform ultrasonic treatment for 1.5 h to obtain the aqueous anti-flash rust and salt spray resistant additive.

[0080] Table 1 Raw material components and dosages (g) in Examples 1-3

[0081]

[0082] Example 4

[0083] An aqueous anti-flash rust and salt spray resistant additive, which is different from that in Example 3 in that: the modified rare earth salt solution in this example is the modified rare earth salt solution prepared in Preparation Example 4.

[0084] Example 5

[0085] An aqueous anti-flash rust and salt spray resistant additive, which is different from that in Example 3 in that: the modified rare earth salt solution in this example is the modified rare earth salt solution prepared in Preparation Example 5.

[0086] Example 6

[0087] An aqueous anti-flash rust and salt spray resistant additive, which is different from that in Example 3 in that: the raw materials in this example further include 10 g of a ferrous sulfate solution with a mass concentration of 10% and 5 g of zinc powder, and the average particle size of the zinc powder is 5 microns. The ferrous sulfate solution and the zinc powder are added in steps S1 and S2 respectively in the preparation method of the additive.

[0088] Example 7

[0089] An aqueous anti-flash rust and salt spray resistant additive, which is different from that in Example 3 in that: the raw materials in this example further include 7 g of a ferrous sulfate solution with a mass concentration of 15% and 6 g of zinc powder, and the average particle size of the zinc powder is 5 microns. The ferrous sulfate solution and the zinc powder are added in steps S1 and S2 respectively in the preparation method of the additive.

[0090] Example 8

[0091] An aqueous anti-flash rust and salt spray resistant additive, which is different from that in Example 3 in that: the raw materials in this example further include 5 g of a ferrous sulfate solution with a mass concentration of 20% and 8 g of zinc powder, and the average particle size of the zinc powder is 5 microns. The ferrous sulfate solution and the zinc powder are added in steps S1 and S2 respectively in the preparation method of the additive.

[0092] Comparative Example

[0093] Comparative Example 1

[0094] Adopt the preparation scheme of a conventional aqueous anti - flash rust and salt - spray resistant additive for coatings in the market. Add 75 g of ethanolamine, 20 g of ammonium molybdate, 60 g of ammonium benzoate, and 20 g of benzotriazole to 85 g of deionized water in sequence. Stir at room temperature for 1 h to obtain the aqueous anti - flash rust and salt - spray resistant additive.

[0095] Comparative Example 2

[0096] An aqueous anti - flash rust and salt - spray resistant additive, the difference from Example 3 is that in this example, an equal amount of unmodified Ce(NO3)3 solution is used instead of the modified rare - earth salt solution of Preparation Example 3.

[0097] Comparative Example 3

[0098] An aqueous anti - flash rust and salt - spray resistant additive, the difference from Example 3 is that the modified rare - earth salt solution in this example is the modified rare - earth salt solution prepared in Preparation Example 6.

[0099] Performance Detection Test

[0100] Test Example 1

[0101] Put 20 g of epoxy resin and 30 g of aqueous curing agent into a vacuum - assisted planetary mixer, and keep the vacuum degree at - 0.10 MPa to obtain an aqueous epoxy resin matrix; take 0.5 g of the aqueous anti - flash rust and salt - spray resistant additive of Example 1 and add it to 10 g of water, perform ultrasonic treatment for 2 h, with an ultrasonic power of 200 W and an ultrasonic frequency of 50 kHz to obtain a dispersion; add the dispersion to the aqueous epoxy resin matrix and stir at 200 rpm for 3 h to obtain a coating sample.

[0102] The preparation methods of the coating samples corresponding to the remaining Examples 2 - 8 and Comparative Examples 1 - 3 are the same as those of Test Example 1.

[0103] Test 1 Anti - flash Rust Performance Test

[0104] Drop 2 drops of the coating samples prepared with the additives of Examples 1 - 8 and Comparative Examples 1 - 3 onto cold - rolled steel plates respectively, and then place the steel plates in a closed environment for 120 h to observe the degree of rust. The humidity in the closed environment is controlled by water, saturated ammonium sulfate aqueous solution, and saturated sodium chloride aqueous solution respectively. The relative humidity of the closed environment with water added is 90%, the relative humidity of the closed environment with saturated ammonium sulfate aqueous solution added is 80%, and the relative humidity of the closed environment with saturated sodium chloride aqueous solution added is 80%. The temperature in the closed environment is 30 °C. The test results are shown in Table 2.

[0105] Table 2 Anti - flash Rust Performance Test Results

[0106]

[0107] Test 2 Salt Spray Resistance Performance Test

[0108] The coating prepared in Test Example 1 was tested for its salt spray resistance performance according to the method specified in "GB / T 1771-2007 Paints and varnishes - Determination of resistance to neutral salt spray". The results are shown in Table 3.

[0109] Table 3 Test Results of Salt Spray Resistance Performance

[0110]

[0111] Test 3 Temperature Resistance Performance Test

[0112] Two drops of the coating prepared in Test Example 1 were dropped onto cold-rolled steel plates, and then the steel plates were placed in a closed environment for 120 h to observe the degree of rusting. The humidity in the closed environment was controlled by water, saturated ammonium sulfate aqueous solution, and saturated sodium chloride aqueous solution respectively. The relative humidity of the closed environment with water added was 90%, the relative humidity of the closed environment with saturated ammonium sulfate aqueous solution added was 80%, and the relative humidity of the closed environment with saturated sodium chloride aqueous solution added was 80%. The temperature in the closed environment was 90 °C. The test results are shown in Table 4.

[0113] Table 4 Test Results of Temperature Resistance Performance

[0114]

[0115] The anti-flash rust and salt spray resistant additives in the coatings of Examples 1-5 used a modified rare earth salt solution. The modified rare earth salt solution formed a complex with a tight structure through the complexation reaction of 4-hydroxy-β-dihydrodamascenone and rare earth ions. The complex with a tight structure not only enhanced the salt spray resistance performance of the coating but also stabilized free radicals at high temperatures, slowed down the propagation rate of the chain reaction, thereby reducing the reaction rate of the coating with oxygen. Therefore, the coatings in Examples 1-5 could still maintain good anti-flash rust performance under high-temperature conditions.

[0116] The anti-flash rust and salt spray resistant additives in the coatings of Examples 6-8 added ferrous sulfate and zinc powder. Since ferrous sulfate and zinc powder formed a weak electric field effect in the coating, it enhanced the adsorption ability of ions or molecules in the coating on the metal surface. At high temperatures, as the temperature increased, the reaction rate between ferrous sulfate and zinc powder accelerated, and the electric field effect enhanced, thereby further enhancing the adsorption ability on the metal surface and the film-forming efficiency. This helped to hinder the electrochemical corrosion of the metal substrate with the electrolyte aqueous solution in the coating, thus improving the anti-flash rust performance of the coating under high-temperature conditions.

[0117] The coating in Comparative Example 1 uses components such as ethanolamine, ammonium molybdate, ammonium benzoate, and benzotriazole. These components cannot form stable free radicals or provide sufficient protective barriers against metal corrosion at high temperatures. Therefore, at high temperatures, the coating in Comparative Example 1 showed dark brown rusting, indicating poor anti-flash rust performance under high-temperature conditions.

[0118] Comparative Example 2 and Comparative Example 3 respectively used unmodified Ce(NO3)3 solution and rare earth salt solution modified with ethylenediaminetetraacetic acid. The unmodified Ce(NO3)3 solution cannot form the same tight structural complex as in the examples, so it cannot provide sufficient protection against metal corrosion at high temperatures. Therefore, the coating in Comparative Example 2 has severely insufficient anti-flash rust performance under high-temperature conditions, resulting in light brown and dark brown rusting. In addition, the modified rare earth salt solution in Comparative Example 3 uses a rare earth salt solution modified with ethylenediaminetetraacetic acid. Since the complex formed by ethylenediaminetetraacetic acid and rare earth ions is not as stable as 4-hydroxy-β-dihydrodamascenone, the anti-flash rust performance of the coating decreases at high temperatures.

[0119] This specific embodiment is only an interpretation of the present application and is not a limitation to the present application. Those skilled in the art can make modifications without creative contributions to this embodiment according to needs after reading this specification, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A water-based anti-flash rust and salt spray resistant additive, characterized in that: The invention comprises the following raw materials in parts by weight: 50-65 parts of sodium ethylenediaminetetramethylenephosphonate; 60-70 parts of N,N-dimethyldodecylamine; 20-40 parts of polydimethylsiloxane; 20-30 parts of nano calcium carbonate; 25-40 parts of modified rare earth salt solution; 30-50 parts of deionized water; The modified rare earth salt solution is prepared by the following method: A. adding 4-hydroxy-β-dihydrodamascone to acetone and heating to dissolve to obtain solution A; B. Using dilute nitric acid to adjust the pH of the rare earth salt solution to 6.5-7 to obtain solution B; C. Slowly add solution B to solution A under magnetic stirring, and stir the reaction at 50-60° C. for 4-5 hours to obtain a modified rare earth salt solution; The volume ratio of 4-hydroxy-β-dihydrodamascone to acetone is 1:(4-5); the volume ratio of solution B to solution A in step c is 1:(0.5-0.8); The rare earth salt solution is any one of Ce(NO3)3, La(NO3)3, and Pr(NO3)3.

2. The water-based anti-flash rust and salt spray resistant additive according to claim 1, characterized in that: It also includes 5-10 parts of ferrous sulfate solution and 5-8 parts of zinc powder.

3. The water-based anti-flash rust and salt spray resistant additive according to claim 2, characterized in that: The concentration of the ferrous sulfate solution is 10%-20%.

4. The water-based anti-flash rust and salt spray resistant additive according to claim 1, characterized in that: The average molecular weight of the polydimethylsiloxane is 5000-10000 Da.

5. The water-based anti-flash rust and salt spray resistant additive according to claim 1, characterized in that: The average particle size of the nano calcium carbonate is 20-100 nm.

6. A method for preparing the water-based anti-flash rust and salt spray resistant additive according to any one of claims 2 to 5, characterized in that: The steps include: S1. Mixing sodium ethylenediaminetetramethylenephosphonate, N,N-dimethyldodecylamine, a modified rare earth salt solution, a ferrous sulfate solution and deionized water at 30-50° C. and stirring for 0.5-1.5 h to obtain a preformed solution; S2. After mixing polydimethylsiloxane, nano-calcium carbonate and zinc powder with the prefabricated liquid, stirring for 0.5-1.5 hours, and then ultrasonically treating for 0.5-1.5 hours to obtain a water-based anti-flash rust and salt spray resistant additive.

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