CN-121975400-A - Marine spare flame-retardant corrosion-resistant coating and preparation method thereof

Abstract

The invention discloses a standby flame-retardant corrosion-resistant coating for a sea tool and a preparation method thereof. According to the method, imidazole ionic liquid with cations containing alkoxy silane groups and epoxy resin containing hydroxyl groups are mixed in a solvent, the alkoxy silane groups on the cations of the ionic liquid and the hydroxyl groups on the molecular chains of the epoxy resin undergo condensation reaction under the microwave auxiliary condition to form Si-O-C covalent bonds, covalent grafting of the ionic liquid on the molecular chains of the resin is realized, and the obtained modified resin and a curing agent are mixed and cured to obtain the coating. The invention solves the problem of migration and precipitation of the ionic liquid by replacing physical blending through covalent grafting, remarkably improves the compactness and long-term stability of the coating, simultaneously realizes excellent flame retardance and corrosion resistance with extremely low addition amount by integrating the dual functions of corrosion inhibition and flame retardance in single ionic liquid molecule, and is suitable for protecting marine equipment and other severe corrosion environments.

Inventors

• XIA YU
• CUI JINCAN
• ZHANG LEI
• Gu Bangxuan
• WANG XUE
• DAI QIBIN
• WANG YU
• WANG HENG
• SUN XIAOFEI

Assignees

• 南通大学

Dates

Publication Date

20260505

Application Date

20260324

Claims (10)

1. 1. The marine tool standby flame-retardant and corrosion-resistant coating is characterized by comprising flame-retardant and corrosion-resistant resin and a curing agent; The flame-retardant corrosion-resistant resin is modified epoxy resin, the modified epoxy resin is formed by covalent grafting of imidazole ionic liquid with a silane side chain and the epoxy resin through condensation reaction, and the structure of the modified epoxy resin contains Si-O-C covalent bonds generated by the reaction of the silane side chain and hydroxyl groups on the epoxy resin; the anions of the ionic liquid are anions containing flame retardant elements.
2. 2. The marine tool backup flame retardant and corrosion resistant coating of claim 1 wherein the raw materials for preparing the modified epoxy resin comprise bisphenol a epoxy resin, 1-trimethoxysilylpropyl-3-methylimidazole chloride salt, and an anionic salt for providing flame retardant anions.
3. 3. The marine tool backup flame retardant corrosion resistant coating of claim 2, wherein the anionic salt is one or more of potassium hexafluorophosphate, sodium tetrafluoroborate and sodium iodide salts.
4. 4. A marine tooling ready-to-use flame retardant, corrosion resistant coating according to claim 3, wherein the bisphenol a epoxy resin has a molecular weight between 700 and 4000; The molar ratio of the 1-trimethoxysilylpropyl-3-methylimidazole chloride salt to the anion salt is 1:0.9-1.1, and the mass ratio of the bisphenol A epoxy resin to the 1-trimethoxysilylpropyl-3-methylimidazole chloride salt is 1:0.05-0.15.
5. 5. The marine tool backup flame retardant corrosion resistant coating of claim 4, wherein the curing agent is a phenolic amine curing agent; the mass ratio of the flame-retardant and corrosion-resistant resin to the phenolic amine curing agent is 1:0.3.
6. 6. The method for preparing the marine tool standby flame-retardant and corrosion-resistant coating according to claim 5, comprising the following steps: S1, synthesizing flame-retardant and corrosion-resistant resin, namely mixing a solvent with a buffer solution to form a weak acid system, adding imidazole ionic liquid with a silane side chain, epoxy resin and anionic salt into the weak acid system, uniformly mixing, and then placing the mixture in a microwave synthesizer for microwave heating reaction; S2, preparing a coating, namely uniformly mixing the flame-retardant and corrosion-resistant resin obtained in the step S1 with a curing agent, coating the mixture on the surface of a substrate, and curing the mixture to obtain the marine tool standby flame-retardant and corrosion-resistant coating.
7. 7. The method according to claim 6, wherein in S1, the buffer solution is composed of anhydrous sodium acetate and glacial acetic acid; to each liter of the solvent was added 0.52 g anhydrous sodium acetate and 0.22 g glacial acetic acid to provide the weakly acidic system.
8. 8. The method according to claim 6 or 7, wherein in S1, the anionic salt is a potassium hexafluorophosphate salt, a sodium tetrafluoroborate salt or a sodium iodide salt; when the anionic salt is potassium hexafluorophosphate salt, the solvent adopts acetone; when the anion salt is tetrafluoroboric acid sodium salt, the solvent adopts acetone, dimethylformamide or acetonitrile; when the anionic salt is a sodium iodide salt, the solvent is acetone or acetonitrile.
9. 9. The method according to claim 6, wherein in S1, the microwave power of the microwave heating reaction is controlled to be 100-300W, the constant temperature in the reaction process is controlled to be 50-60 ℃, and the effective microwave time is 30 min-4 h.
10. 10. The preparation method according to claim 6, wherein in S1, the imidazole ionic liquid with a silane side chain is 1-trimethoxysilylpropyl-3-methylimidazole chloride; And after the reaction is finished, removing the solvent by rotary evaporation, and repeatedly washing the product by using deionized water or acetone until the washing liquid does not generate white precipitate after being detected by silver nitrate, wherein in the step S2, the curing condition is curing at normal temperature of 1.5 h.

Description

Marine spare flame-retardant corrosion-resistant coating and preparation method thereof Technical Field The invention relates to the field of marine protective materials, in particular to a standby flame-retardant corrosion-resistant coating for a marine tool and a preparation method thereof. Background The marine environment is a typical severe corrosion environment, and seawater is rich in strong corrosive media such as chloride ions, sulfate ions and the like, so that the marine environment forms a continuous threat to the metal structure of marine equipment. Meanwhile, the sea tool has a closed inner space, dense electrical equipment and concentrated various inflammable materials, and the fire risk is prominent. Therefore, the surface coating of the marine tool needs to have both excellent corrosion resistance and flame retardance. Epoxy resins are widely used as matrix materials for marine protective coatings due to their good adhesion, chemical stability and film forming properties, but pure epoxy resins are inherently flammable and must be flame retardant modified. The mainstream flame retardant modification mode at present is to physically blend flame retardant or flame retardant ionic liquid into epoxy resin. However, there are three inherent drawbacks to physical blending approaches that are difficult to overcome. Firstly, the flame retardant component is dispersed in a coating matrix in a free state, is maintained with resin only by virtue of weak interactions such as Van der Waals force, is easy to migrate and separate out in a marine long-term damp and hot environment, not only leads to gradual attenuation of flame retardant performance, but also leaves microscopic pore channels and defects in the coating after separation, and accelerates penetration of corrosive media to synchronously deteriorate corrosion resistance. Secondly, the contradiction between flame retardant performance and corrosion resistance exists, the addition amount of flame retardant components is often higher to achieve the ideal flame retardant grade, and a large amount of added flame retardant components can damage the compactness of the coating to form a permeation channel of corrosive medium, so that the two performances are difficult to realize simultaneously in the same coating. And thirdly, even if the ionic liquid with higher flame retardant efficiency is adopted to reduce the addition amount, when the ionic liquid is considered to be covalently grafted to a resin molecular chain in order to solve the precipitation problem, the condensation reaction of the silane group and the epoxy resin hydroxyl group has extremely low speed and low grafting rate under the conventional mild condition, the requirement of the coating performance is difficult to meet, and the feasibility of a covalent grafting strategy in the actual coating preparation is limited. Disclosure of Invention The invention aims to provide a standby flame-retardant corrosion-resistant coating for a sea tool and a preparation method thereof, wherein flame-retardant ionic liquid is chemically grafted onto epoxy resin based on a microwave synthesis technology, so that the effect of high-efficiency grafting of the ionic liquid in the coating under mild conditions is realized. The ionic liquid selected by the invention can be attached to carbon steel to form a protective layer, so that the coating has an anti-corrosion function. The low-toxicity ionic liquid has the flame retardance and the corrosion inhibition functions, so that the core technical problem that the flame retardance and the corrosion resistance are mutually influenced is successfully solved, and an innovative coating with long-acting and high-efficiency flame retardance and corrosion resistance is provided for sea equipment. In order to achieve the aim, the invention provides the technical scheme that the marine tool standby flame-retardant and corrosion-resistant coating comprises flame-retardant and corrosion-resistant resin and a curing agent; the flame-retardant corrosion-resistant resin is modified epoxy resin, the modified epoxy resin is formed by covalent grafting of imidazole ionic liquid with a silane side chain and the epoxy resin through condensation reaction, the structure of the modified epoxy resin contains Si-O-C covalent bonds generated by the reaction of the silane side chain and hydroxyl groups on the epoxy resin, and anions of the ionic liquid are anions containing flame-retardant elements. Further, in the present invention, the raw materials for preparing the modified epoxy resin include bisphenol A epoxy resin, 1-trimethoxysilylpropyl-3-methylimidazole chloride salt, and anion salt for providing flame retardant anions. Further, in the present invention, the anionic salt is one or more of potassium hexafluorophosphate, sodium tetrafluoroborate and sodium iodide. Further, in the present invention, the molecular weight of the bisphenol a epoxy resin is between 700 and 4000; The