Preparation method of novel corrosion-resistant coating for metal material

Abstract

The invention relates to a preparation method of a novel corrosion-resistant coating for a metal material, and belongs to the technical field of metal corrosion-resistant coatings. The preparation method comprises the following steps: sequentially adding 3, 3-diamino-4, 4-dicarboxyl biphenyl and cerous nitrate into a reaction kettle with a mixed solvent, carrying out ultrasonic treatment and heating reaction, distilling to remove the mixed solvent, and cooling to room temperature to obtain a cerium-containing precursor; the preparation method comprises the following steps: adding epoxy resin and epoxy cyclohexyl-polyhedral oligomeric silsesquioxane into solvent oil, then adding a cerium-containing precursor, carrying out a heating reaction, and carrying out ultrasonic treatment; continuously adding a curing agent, and stirring to obtain the novel corrosion-resistant coating. Coating the cleaned metal hook by using a dip-coating method, and drying at room temperature; the novel corrosion-resistant coating prepared by the preparation method disclosed by the invention is good in humidity and heat resistance and excellent in corrosion resistance.

Description

Technical Field

[0001] This invention relates to the field of metal corrosion-resistant coating technology, and in particular to a method for preparing a novel corrosion-resistant coating for metal materials. Background Technology

[0002] The most common and important method for metal corrosion protection is coating technology, which has been widely applied in corrosion protection across various industries. Coating protection involves preparing protective coatings of various materials on the metal surface. Through passivation, shielding, and corrosion inhibition, the coating prevents corrosive media from contacting the metal, thereby reducing the rate of corrosion.

[0003] Chinese Patent CN102585702A discloses a metal anti-corrosion and anti-rust coating and its application. The coating is composed of the following components by weight percentage: 60-90% asphalt, 5-30% metal protectant, and 5-35% metal penetrant. The raw materials for this coating are readily available and the preparation is simple, requiring only simple mixing. Each component in the coating has a different function, forming three mutually adhering paint films on the metal surface, effectively isolating the metal from the external environment.

[0004] Chinese Patent CN104761943B discloses a corrosion-resistant coating for magnesium alloys, comprising zinc powder, aluminum powder, zirconium oxide, yttrium oxide, yttrium nitrate, polyethylene glycol, sodium molybdate, hydroxymethyl cellulose, silane coupling agent KH560, diphenyldimethoxysilane, and deionized water mixed uniformly in a certain proportion. This invention also provides a method for improving the corrosion resistance of magnesium alloys using this coating, comprising the following steps: 1. Pretreatment of the magnesium alloy surface; 2. Coating the magnesium alloy surface with the coating; 3. Preheating treatment; 4. Curing treatment to form a corrosion-resistant coating on the magnesium alloy surface.

[0005] Chinese Patent CN104060273B discloses a long-lasting corrosion-resistant coating for steel structures, comprising the following components by mass percentage: barium sulfate 1-4%, zinc phosphate 0.1-2%, ferric oxide 0.5-3%, ferric oxide 0.1-2%, alpha-carboxylated iron oxide 0.2-3%, phosphoric acid 2-6%, montmorillonite 0.5-2%, polyvinyl butyral resin 2-8%, and ethanol 70-80%.

[0006] The corrosion-resistant coatings prepared by the above patents and existing technologies have poor resistance to damp heat, and their corrosion resistance needs to be further improved. Summary of the Invention

[0007] To address the above problems, this invention provides a method for preparing a novel corrosion-resistant coating for metallic materials, comprising the following steps: S1: By weight, 8-16 parts of 3,3-diamino-4,4-dicarboxybiphenyl (CAS: 1799740-97-8) and 27-33 parts of cerium nitrate were added sequentially to a reaction vessel containing 140-150 parts of mixed solvent. After ultrasonic treatment for 10-20 minutes, the mixture was heated to react, the mixed solvent was removed by distillation, and the mixture was cooled to room temperature to obtain the cerium-containing precursor. S2: Add 12-18 parts of epoxy resin E44 and 0.3-0.7 parts of epoxy cyclohexyl-cage polysilsesquioxane (CAS No.: 187333-74-0) to 120-130 parts of solvent oil, then add 0.04-0.4 parts of the cerium-containing precursor prepared in S1, and react at 60-75℃ for 1-3 hours; ultrasonically treat for 10-20 minutes; continue to add 2-6 parts of curing agent, stir for 10-20 minutes, and obtain a new type of corrosion-resistant coating; S3: Apply a coating to the cleaned metal hook using the dip-coating method and allow it to dry at room temperature.

[0008] The mixed solvent is N,N-dimethylacetamide, ethanol, and deionized water in a volume ratio of 1:1:1.

[0009] The reaction temperature of S1 is 90-100℃, and the reaction time is 40-50h.

[0010] The curing agent is polyamide 650 or polyamide 651.

[0011] The soaking time for the dip-coating method is 5-10 minutes, the lifting speed is 60-100 mm / min, and the coating is applied once.

[0012] The room temperature drying time for S3 is 18-24 hours.

[0013] Reaction mechanism Complex formation: The carboxyl oxygen of 3,3-diamino-4,4-dicarboxybiphenyl coordinates with the cerium ion of cerium nitrate to form a diaminobiphenyl cerium complex.

[0014] Ring-opening addition: The amino group of the complex nucleophilically attacks the epoxy group of the epoxy resin and the epoxy cyclohexyl-cage polysilsesquioxane, resulting in a ring-opening reaction and achieving linkage.

[0015] Curing: After ring opening, the remaining active groups continue to react, and the molecular chains cross-link to form a three-dimensional network structure, thus curing the coating.

[0016] Technical effect The present invention discloses a method for preparing a novel corrosion-resistant coating for metallic materials. Compared with the prior art, the present invention has the following significant advantages: 1. Improved corrosion resistance: Cerium ions form a passivation film and act as a corrosion inhibitor. The dense structure of the coating acts as a shield, blocking corrosive media.

[0017] 2. Enhanced mechanical properties: Epoxy resin provides strength and adhesion, while cage-like polysilsesquioxane increases rigidity and toughness.

[0018] 3. Improved thermal stability: Cerium complexes resist oxidation, and the silicon-oxygen bonds of cage-like polysilsesquioxanes ensure structural stability of the coating at high temperatures.

[0019] 4. Improved chemical stability: Biphenyl and other components make the coating resistant to chemical corrosion. Detailed Implementation

[0020] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following detailed description is provided in conjunction with embodiments and comparative examples: 1. Moist heat resistance test: The test shall be conducted in accordance with GB / T1740 for 1000 hours.

[0021] 2. Salt spray test: The neutral salt spray test shall be conducted in accordance with GB / T10125-2021. The corrosive solution shall be a 50 g / L sodium chloride solution with a neutral pH value and the test temperature shall be room temperature. Example 1

[0022] A method for preparing a novel corrosion-resistant coating for metallic materials, comprising the following steps: S1: 8g of 3,3-diamino-4,4-dicarboxybiphenyl (CAS: 1799740-97-8) and 27g of cerium nitrate were added sequentially to a reaction vessel containing 140g of mixed solvent. After ultrasonic treatment for 10min, the mixture was heated to react, the mixed solvent was removed by distillation, and the mixture was cooled to room temperature to obtain the cerium-containing precursor. S2: 12g of epoxy resin E44 and 0.3g of epoxy cyclohexyl-cage polysilsesquioxane (CAS No.: 187333-74-0) were added to 120g of solvent oil, followed by 0.04g of the cerium-containing precursor prepared in S1. The mixture was reacted at 60℃ for 1h; ultrasonically treated for 10min; and then 2g of curing agent was added and stirred for 10min to obtain a novel corrosion-resistant coating. S3: Apply a coating to the cleaned metal hook using the dip-coating method and allow it to dry at room temperature.

[0023] The mixed solvent is N,N-dimethylacetamide, ethanol, and deionized water in a volume ratio of 1:1:1.

[0024] The reaction temperature of S1 is 90℃ and the reaction time is 40h.

[0025] The curing agent is polyamide 650.

[0026] The soaking time for the dip-coating method is 5 minutes, the lifting speed is 60 mm / min, and the coating is applied once.

[0027] The room temperature drying time for S3 is 18 hours. Example 2

[0028] A method for preparing a novel corrosion-resistant coating for metallic materials, comprising the following steps: S1: 10g of 3,3-diamino-4,4-dicarboxybiphenyl (CAS: 1799740-97-8) and 29g of cerium nitrate were added sequentially to a reaction vessel containing 145g of mixed solvent. After ultrasonic treatment for 15min, the mixture was heated to react, the mixed solvent was removed by distillation, and the mixture was cooled to room temperature to obtain the cerium-containing precursor. S2: 14g of epoxy resin E44 and 0.4g of epoxy cyclohexyl-cage polysilsesquioxane (CAS No.: 187333-74-0) were added to 125g of solvent oil, followed by 0.2g of the cerium-containing precursor prepared in S1. The mixture was reacted at 65℃ for 1.5h, ultrasonically treated for 15min, and then 3g of curing agent was added and stirred for 15min to obtain a novel corrosion-resistant coating. S3: Apply a coating to the cleaned metal hook using the dip-coating method and allow it to dry at room temperature.

[0029] The mixed solvent is N,N-dimethylacetamide, ethanol, and deionized water in a volume ratio of 1:1:1.

[0030] The reaction temperature of S1 is 95℃ and the reaction time is 44h.

[0031] The curing agent is polyamide 650.

[0032] The soaking time for the dip-coating method is 6 minutes, the lifting speed is 70 mm / min, and the coating is applied once.

[0033] The room temperature drying time for S3 is 20 hours. Example 3

[0034] A method for preparing a novel corrosion-resistant coating for metallic materials, comprising the following steps: S1: 14g of 3,3-diamino-4,4-dicarboxybiphenyl (CAS: 1799740-97-8) and 31g of cerium nitrate were added sequentially to a reaction vessel containing 145g of mixed solvent. After ultrasonic treatment for 15min, the mixture was heated and reacted. The mixed solvent was then removed by distillation and cooled to room temperature to obtain the cerium-containing precursor. S2: 16g of epoxy resin E44 and 0.6g of epoxy cyclohexyl-cage polysilsesquioxane (CAS No.: 187333-74-0) were added to 125g of solvent oil, followed by 0.3g of the cerium-containing precursor prepared in S1. The mixture was reacted at 70℃ for 2.5h; ultrasonically treated for 15min; and then 5g of curing agent was added and stirred for 15min to obtain a novel corrosion-resistant coating. S3: Apply a coating to the cleaned metal hook using the dip-coating method and allow it to dry at room temperature.

[0035] The mixed solvent is N,N-dimethylacetamide, ethanol, and deionized water in a volume ratio of 1:1:1.

[0036] The reaction temperature of S1 is 95℃ and the reaction time is 48h.

[0037] The curing agent is polyamide 651.

[0038] The soaking time for the dip-coating method is 9 minutes, the lifting speed is 90 mm / min, and the coating is applied once.

[0039] The room temperature drying time for S3 is 22 hours. Example 4

[0040] A method for preparing a novel corrosion-resistant coating for metallic materials, comprising the following steps: S1: 16g of 3,3-diamino-4,4-dicarboxybiphenyl (CAS: 1799740-97-8) and 33g of cerium nitrate were added sequentially to a reaction vessel containing 150g of mixed solvent. After ultrasonic treatment for 20min, the mixture was heated to react, the mixed solvent was removed by distillation, and the mixture was cooled to room temperature to obtain the cerium-containing precursor. S2: 18g of epoxy resin E44 and 0.7g of epoxy cyclohexyl-cage polysilsesquioxane (CAS No.: 187333-74-0) were added to 130g of solvent oil, followed by 0.4g of the cerium-containing precursor prepared in S1. The mixture was reacted at 75℃ for 3 hours, ultrasonically treated for 20 minutes, and then 6g of curing agent was added and stirred for 20 minutes to obtain a novel corrosion-resistant coating. S3: Apply a coating to the cleaned metal hook using the dip-coating method and allow it to dry at room temperature.

[0041] The mixed solvent is N,N-dimethylacetamide, ethanol, and deionized water in a volume ratio of 1:1:1.

[0042] The reaction temperature of S1 is 100℃ and the reaction time is 50h.

[0043] The curing agent is polyamide 651.

[0044] The soaking time for the dip-coating method is 10 minutes, the lifting speed is 100 mm / min, and the coating is applied once.

[0045] The room temperature drying time for S3 is 24 hours.

[0046] Comparative Example 1 The same as in Example 1 was used, but without the addition of 3,3-diamino-4,4-dicarboxybiphenyl and epoxycyclohexyl-cage polysilsesquioxane.

[0047] Comparative Example 2 The same as in Example 1 was used, but without the addition of 3,3-diamino-4,4-dicarboxybiphenyl.

[0048] Comparative Example 3 Without adding epoxycyclohexyl-cage polysilsesquioxane, otherwise the same as in Example 1.

[0049] The test results of the examples and comparative examples are shown in Table 1.

[0050] Table 1 Moist heat resistance Salt spray test Example 1 No bubbling, no rusting No change Example 2 No bubbling, no rusting No change Example 3 No bubbling, no rusting No change Example 4 No bubbling, no rusting No change Comparative Example 1 Rust Obvious corrosion Comparative Example 2 foaming Minor pitting Comparative Example 3 foaming Minor pitting Based on the data analysis of the above embodiments and comparative examples, the novel corrosion-resistant coating prepared by the present invention has good resistance to damp heat and excellent corrosion resistance.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing a novel corrosion-resistant coating for metallic materials, comprising the following steps: S1: By weight, 8-16 parts of 3,3-diamino-4,4-dicarboxybiphenyl and 27-33 parts of cerium nitrate are added sequentially to a reaction vessel containing 140-150 parts of mixed solvent. After ultrasonic treatment for 10-20 minutes, the mixture is heated to react, the mixed solvent is removed by distillation, and the mixture is cooled to room temperature to obtain the cerium-containing precursor. S2: Add 12-18 parts of epoxy resin and 0.3-0.7 parts of epoxy cyclohexyl-cage polysilsesquioxane to 120-130 parts of solvent oil, then add 0.04-0.4 parts of the cerium-containing precursor prepared in S1, and react at 60-75℃ for 1-3 hours; ultrasonically treat for 10-20 minutes; continue to add 2-6 parts of curing agent, stir for 10-20 minutes, and obtain a new type of corrosion-resistant coating; S3: Apply a coating to the cleaned metal hook using the dip-coating method and allow it to dry at room temperature.

2. The method for preparing a novel corrosion-resistant coating for metallic materials according to claim 1, characterized in that: The mixed solvent is N,N-dimethylacetamide, ethanol, and deionized water in a volume ratio of 1:1:

1.

3. The method for preparing a novel corrosion-resistant coating for metallic materials according to claim 1, characterized in that: The reaction temperature of S1 is 90-100℃, and the reaction time is 40-50h.

4. The method for preparing a novel corrosion-resistant coating for metallic materials according to claim 1, characterized in that: The curing agent is polyamide 650 or polyamide 651.

5. The method for preparing a novel corrosion-resistant coating for metallic materials according to claim 1, characterized in that: The soaking time for the dip-coating method is 5-10 minutes, the lifting speed is 60-100 mm / min, and the coating is applied once.

6. The method for preparing a novel corrosion-resistant coating for metallic materials according to claim 1, characterized in that: The room temperature drying time for S3 is 18-24 hours.