Flame retardant and corrosion resistant coating and preparation method thereof

Abstract

The present invention discloses a flame-retardant and corrosion-resistant coating and a preparation method thereof, and relates to the technical field of coatings. When preparing the flame-retardant and corrosion-resistant coating, the present invention comprises the following steps: reacting hexaarylbiimidazole and epichlorohydrin to obtain epoxidized hexaarylbiimidazole; reacting pre-modified mica flakes and 3-aminopropyltriethoxysilane to obtain modified mica flakes; reacting allylamine and 4'-[4-(bromomethyl)phenyl]-2,2':6',2"-terpyridine to obtain allyl terpyridine; reacting epoxy resin and allyl terpyridine to obtain modified epoxy resin; and uniformly mixing the modified epoxy resin, epoxidized hexaarylbiimidazole, modified mica flakes, isophorone diamine, and acetone to obtain the flame-retardant and corrosion-resistant coating. The flame-retardant and corrosion-resistant coating prepared by the present invention has excellent corrosion resistance, flame retardancy, and self-repairing properties.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, in particular to a flame retardant and corrosion resistant coating and a preparation method thereof. Background Art

[0002] Metal corrosion refers to the destruction or deterioration caused by chemical or electrochemical reactions between metals and the medium in the surrounding environment. The phenomenon of metal corrosion is prevalent in various fields such as the national economy and national defense construction, causing huge losses to the national economy. In order to extend the service life of metal materials, people have taken many protective measures, mainly including cathodic protection and anti-corrosion coatings. Among them, anti-corrosion coatings are one of the most commonly used measures in corrosion protection. Its protective mechanism is to provide a barrier to isolate metal materials from the corrosive environment and corrosive media. However, most anti-corrosion coatings are organic substances with a single anti-corrosion mechanism. They are easily damaged and aged over time, and their anti-corrosion performance on metal materials will also decrease. Therefore, it is necessary to improve the existing technology, enhance the anti-corrosion performance of the coating, and at the same time give the coating self-healing properties to extend the service life of the coating. Summary of the Invention

[0003] The purpose of the present invention is to provide a flame retardant and corrosion resistant coating and a preparation method thereof, so as to solve the problems existing in the prior art.

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0005] A flame retardant and corrosion resistant coating is prepared by reacting hexaarylbiimidazole and epichlorohydrin to obtain epoxidized hexaarylbiimidazole; reacting pre-modified mica flakes and 3-aminopropyltriethoxysilane to obtain modified mica flakes; reacting epoxy resin and allyl terpyridine to obtain modified epoxy resin; and uniformly mixing the modified epoxy resin, epoxidized hexaarylbiimidazole, modified mica flakes, isophorone diamine, and acetone.

[0006] The hexaarylbiimidazole is prepared by oxidizing triphenylimidazole;

[0007] The triphenylimidazole is prepared by reacting 2-chlorobenzaldehyde and 4,4'-dihydroxybenzil;

[0008] The pre-modified mica sheet is prepared by polymerizing and coating 4,6-di(phenyl)-2-prop-2-enyl-1,3-dioxa-2-phosphacyclohexane 2-oxide and 1-vinyl-3-chloromethyl-1,1,3,3-tetramethyldisiloxane on a mica sheet;

[0009] The allyl terpyridine is prepared by reacting allylamine and 4'-[4-(bromomethyl)phenyl]-2,2':6',2"-terpyridine.

[0010] A method for preparing a flame retardant and corrosion resistant coating, comprising the following steps:

[0011] (1) Hexaarylbiimidazole and epichlorohydrin are added in a molar ratio of 1:4 to N,N-dimethylformamide (12 to 14 times the mass of hexaarylbiimidazole), and a 10% sodium hydroxide aqueous solution (2 to 2.2 times the mass of hexaarylbiimidazole) is added. The mixture is stirred at 80 to 82°C and 200 to 300 r / min for 4 to 5 hours under nitrogen protection, and dried at 60 to 70°C for 8 to 10 hours under vacuum conditions to obtain epoxidized hexaarylbiimidazole.

[0012] (2) pre-modified mica flakes, 3-aminopropyltriethoxysilane, triethylamine, and tetrahydrofuran were mixed uniformly in a mass ratio of 1:(2-3):(0.03-0.05):(20-22), stirred at 50-60°C and 200-300 r / min for 2-3 h, filtered, washed with anhydrous ethanol and deionized water 3-5 times each, and dried at 70-80°C under vacuum conditions for 8-10 h to obtain modified mica flakes;

[0013] (3) Allyl terpyridine, benzoyl peroxide, and n-butanol are mixed uniformly in a mass ratio of 1:(0.02-0.04):(7-8) to prepare a monomer reaction liquid; epoxy resin, ethylene glycol monobutyl ether, and n-butanol are mixed uniformly in a mass ratio of 1:(1-2):(3-4), placed in a high-pressure reactor, stirred at 102-106°C and 100-120 r / min for 15-25 minutes, and the monomer reaction liquid of 1.2-1.4 times the mass of the epoxy resin is added dropwise at a uniform rate within 18 minutes, the temperature is raised to 120-122°C, the stirring reaction is continued for 2-3 hours, and dried at 50-60°C under vacuum conditions for 10-12 hours to obtain a modified epoxy resin;

[0014] (4) Weigh 78-82 parts of modified epoxy resin, 17-23 parts of epoxidized hexaarylbimidazole, 4-5 parts of modified mica flakes, and 18-20 parts of isophorone diamine by mass; mix the modified epoxy resin, epoxidized hexaarylbimidazole, and modified mica flakes uniformly, stir at 10-30°C and 100-200 r / min for 10-12 minutes, add isophorone diamine, and adjust the viscosity to 300-400 MPa·s with acetone to prepare a flame retardant and corrosion resistant coating.

[0015] As an optimization, the preparation method of the hexaaryl biimidazole in step (1) is as follows: triphenyl imidazole and dichloromethane are uniformly mixed in a mass ratio of 1: (30-40), and a catalyst solution 4 to 5 times the mass of triphenyl imidazole is added dropwise at a uniform rate within 10 minutes under light-proof conditions and stirring conditions of 200 to 300 r / min. After the addition is completed, the stirring reaction is continued at room temperature and pressure in the dark for 10 to 12 hours, and the hexaaryl biimidazole is dried at 70 to 80° C. under vacuum conditions for 8 to 10 hours to obtain the hexaaryl biimidazole.

[0016] As an optimization, the catalyst solution is prepared by uniformly mixing potassium ferricyanide, sodium hydroxide, and deionized water in a mass ratio of 1:(1.2-1.4):(15-17) to prepare a catalyst solution.

[0017] As an optimization, the preparation method of the triphenylimidazole is as follows: 2-chlorobenzaldehyde and 4,4'-dihydroxybenzil are added in a molar ratio of 1:1 to acetic acid 8 to 10 times the mass of 2-chlorobenzaldehyde, and ammonium acetate 0.03 to 0.05 times the mass of 2-chlorobenzaldehyde is added. Under nitrogen protection, the mixture is stirred at 88 to 90°C and 200 to 300 r / min for 10 to 12 hours, and dried at 70 to 80°C under vacuum conditions for 7 to 8 hours to obtain triphenylimidazole. The reaction process is as follows:

[0018]

[0019] As an optimization, the preparation method of the pre-modified mica sheet in step (2) is: the mica sheet and the polymerizable coating reaction liquid accounting for 1 / 5 of the total mass of the polymerizable coating reaction liquid are mixed uniformly in a mass ratio of 1: (20-24), stirred at 70-80°C and 200-300r / min for 60-70min, the remaining polymerizable coating reaction liquid is added, and the stirring reaction is continued for 2-3h, cooled to room temperature, filtered, washed with anhydrous ethanol 3-5 times, and dried at 70-80°C under vacuum conditions for 8-10h to obtain the pre-modified mica sheet.

[0020] As an optimization, the preparation method of the polymerizable coating reaction liquid is: 4,6-di(phenyl)-2-prop-2-enyl-1,3-dioxa-2-phosphacyclohexane 2-oxide, 1-vinyl-3-chloromethyl-1,1,3,3-tetramethyldisiloxane, azobisisobutyronitrile, and toluene are mixed evenly in a mass ratio of 1:(2-2.2):(0.03-0.05):(38-42) to prepare a polymerizable coating reaction liquid.

[0021] As an optimization, the CAS number of the 4,6-di(phenyl)-2-prop-2-enyl-1,3-dioxa-2-phosphacyclohexane 2-oxide is 145051-55-4; the structural formula is:

[0022] As an optimization, the particle size of the mica flakes is 800 mesh.

[0023] As an optimization, the preparation method of the allyl terpyridine in step (3) is as follows: allylamine and 4'-[4-(bromomethyl)phenyl]-2,2':6',2"-terpyridine are added in a molar ratio of 1:1 to N,N-dimethylformamide with a mass of 10 to 12 times that of allylamine, and triethylamine with a mass of 0.03 to 0.05 times that of allylamine is added, and the mixture is stirred at 40 to 50°C and 200 to 300 r / min for 3 to 4 hours, and dried at 50 to 60°C under vacuum conditions for 8 to 10 hours to obtain allyl terpyridine.

[0024] As an optimization, the model of the epoxy resin in step (3) is E44.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] In the preparation of the flame retardant and corrosion resistant coating, 2-chlorobenzaldehyde and 4,4'-dihydroxybenzil are reacted to obtain triphenylimidazole; triphenylimidazole is oxidized to obtain hexaarylbiimidazole; hexaarylbiimidazole and epichlorohydrin are reacted to obtain epoxidized hexaarylbiimidazole; 4,6-di(phenyl)-2-prop-2-enyl-1,3-dioxa-2-phosphacyclohexane 2-oxide and 1-vinyl-3-chloromethyl-1,1,3,3-tetramethyldisiloxane are polymerized and coated on the cloud. A pre-modified mica sheet is prepared on a mother sheet; the pre-modified mica sheet and 3-aminopropyltriethoxysilane are reacted to prepare a modified mica sheet; allylamine and 4'-[4-(bromomethyl)phenyl]-2,2':6',2"-terpyridine are reacted to prepare allyl terpyridine; epoxy resin and allyl terpyridine are reacted to prepare a modified epoxy resin; the modified epoxy resin, epoxidized hexaarylbiimidazole, modified mica sheet, isophorone diamine and acetone are uniformly mixed to prepare a flame retardant and corrosion resistant coating.

[0027] First, 2-chlorobenzaldehyde and 4,4'-dihydroxybenzil are reacted to obtain triphenylimidazole; triphenylimidazole is oxidized to obtain hexaarylbiimidazole; hexaarylbiimidazole and epichlorohydrin are reacted to obtain epoxidized hexaarylbiimidazole; the epoxy group on the epoxidized hexaarylbiimidazole can participate in the curing process of the coating, introducing a hexaarylbiimidazole structure into the coating; the hexaarylbiimidazole structure has photoisomerization. Under the action of ultraviolet light, the CN bond dynamically dissociates into two triphenylimidazole free radicals. Under light-proof and room temperature conditions, the free radicals collide with each other and recombine to form new CN bonds, thereby giving the flame-retardant and corrosion-resistant coating the performance of ultraviolet light response and self-repair. The mechanism of action is as follows:

[0028]

[0029] Secondly, 4,6-di(phenyl)-2-prop-2-enyl-1,3-dioxa-2-phosphacyclohexane 2-oxide and 1-vinyl-3-chloromethyl-1,1,3,3-tetramethyldisiloxane are polymerized and coated on mica sheets to prepare pre-modified mica sheets, and phosphorus elements, Si-O-Si bonds, and chlorine atoms are introduced into the pre-modified mica sheets; the introduction of phosphorus elements and Si-O-Si bonds can improve the flame retardant properties of flame retardant and corrosion-resistant coatings; the chlorine atoms introduced into the pre-modified mica sheets react with the amino groups on 3-aminopropyltriethoxysilane to prepare modified mica sheets; triethoxysilane is introduced into the modified mica sheets, and when the coating encounters the erosion of corrosive substances, triethoxysilane Alkane is hydrolyzed into Si-OH, which forms hydrogen bonds with hydroxyl groups on the surface of metal materials and is adsorbed on the surface of metal materials, thereby improving the adhesion between the coating and the metal materials, thereby improving the corrosion resistance of the flame retardant and corrosion resistant coating. Mica flakes have a lamellar structure. Dispersing mica flakes in the coating can form a physical barrier, extend the diffusion path of penetrating molecules, enhance the barrier ability of the coating, isolate the penetration of gas and liquid, and improve corrosion resistance. However, mica flakes are inorganic materials, and they have poor compatibility when directly added to the coating and are easy to agglomerate. The surface of the mica flakes is modified so that the mica flakes are evenly dispersed in the coating, fully exerting the barrier effect, and further improving the corrosion resistance of the flame retardant and corrosion resistant coating.

[0030] Finally, allylamine and 4'-[4-(bromomethyl)phenyl]-2,2':6',2"-terpyridine are reacted to prepare allyl terpyridine. Although epoxy resin does not have unsaturated double bonds, it contains ether bonds. The α-H atoms on the ortho-carbon and the H atoms on the tertiary carbon atoms are relatively active. Under the action of an initiator, they can form free radicals to initiate a graft polymerization reaction. Allyl terpyridine is grafted onto the side chain of the epoxy resin molecule to prepare a modified epoxy resin. The modified epoxy resin participates in the curing of the coating, and the terpyridine structure is introduced into the coating. The terpyridine structure is a strong ligand for transition metal ions and can complex with metal ions generated during the corrosion process to form a protective complex product on the metal surface, thereby delaying corrosion and further improving the corrosion resistance of the flame-retardant and corrosion-resistant coating. DETAILED DESCRIPTION

[0031] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] Example 1:

[0033] A method for preparing a flame retardant and corrosion resistant coating, comprising the following steps:

[0034] (1) 2-chlorobenzaldehyde and 4,4'-dihydroxybenzil were added to acetic acid with a molar ratio of 1:1, and ammonium acetate with a molar ratio of 0.03 times the mass of 2-chlorobenzaldehyde was added. The mixture was stirred at 88°C and 200 r / min for 12 h under nitrogen protection, and dried at 70°C for 8 h under vacuum conditions to obtain triphenylimidazole. Potassium ferrocyanide, sodium hydroxide, and deionized water were mixed at a mass ratio of 1:1.2:15 to prepare a catalyst solution. Triphenylimidazole and dichloromethane were mixed at a mass ratio of 1:30, stirred at 200 r / min under light-proof conditions, and dried at 1 0min, uniformly adding a catalyst solution of 4 times the mass of triphenylimidazole, after completion of the dropwise addition, continuing to stir and react at room temperature and pressure in the dark for 12h, and drying at 70°C for 10h under vacuum conditions to obtain hexaarylbiimidazole; adding hexaarylbiimidazole and epichlorohydrin in a molar ratio of 1:4 to N,N-dimethylformamide of 12 times the mass of hexaarylbiimidazole, adding a 10% sodium hydroxide aqueous solution of 2 times the mass of hexaarylbiimidazole, stirring and reacting at 80°C and 200r / min under nitrogen protection for 5h, and drying at 60°C for 10h under vacuum conditions to obtain epoxidized hexaarylbiimidazole;

[0035] (2) 4,6-di(phenyl)-2-prop-2-enyl-1,3-dioxa-2-phosphacyclohexane 2-oxide, 1-vinyl-3-chloromethyl-1,1,3,3-tetramethyldisiloxane, azobisisobutyronitrile and toluene were mixed in a mass ratio of 1:2:0.03:38 to prepare a polymerizable coating reaction solution; mica flakes and a polymerizable coating reaction solution accounting for 1 / 5 of the total mass of the polymerizable coating reaction solution were mixed in a mass ratio of 1:20, stirred at 70°C and 200 r / min for 70 minutes, and added The remaining polymerizable coating reaction liquid was stirred and reacted for 3 hours, cooled to room temperature, filtered, washed with anhydrous ethanol 3 times, and dried at 70°C for 10 hours under vacuum conditions to obtain pre-modified mica sheets; the pre-modified mica sheets, 3-aminopropyltriethoxysilane, triethylamine, and tetrahydrofuran were mixed uniformly in a mass ratio of 1:2:0.03:20, stirred and reacted at 50°C and 200 r / min for 3 hours, filtered, washed with anhydrous ethanol and deionized water 3 times each, and dried at 70°C for 10 hours under vacuum conditions to obtain modified mica sheets;

[0036] (3) Allylamine and 4'-[4-(bromomethyl)phenyl]-2,2':6',2"-terpyridine were added in a molar ratio of 1:1 to N,N-dimethylformamide (10 times the mass of allylamine), and triethylamine (0.03 times the mass of allylamine) was added. The mixture was stirred at 40°C and 200 r / min for 4 hours, and dried at 50°C for 10 hours under vacuum conditions to obtain allyl terpyridine. Allyl terpyridine, benzoyl peroxide, and n-butanol were added in a mass ratio of 1:0.02:7 were mixed to prepare a monomer reaction liquid; epoxy resin E44, ethylene glycol monobutyl ether, and n-butanol were mixed in a mass ratio of 1:1:3, placed in a high-pressure reactor, stirred at 102°C and 100 r / min for 25 minutes, and the monomer reaction liquid 1.2 times the mass of epoxy resin E44 was added dropwise at a uniform rate over 18 minutes. The temperature was raised to 120°C, and the stirring reaction was continued for 3 hours. The modified epoxy resin was dried at 50°C under vacuum conditions for 12 hours to obtain the modified epoxy resin;

[0037] (4) Weigh 78 parts of modified epoxy resin, 17 parts of epoxidized hexaarylbimidazole, 4 parts of modified mica flakes, and 18 parts of isophorone diamine by mass; mix the modified epoxy resin, epoxidized hexaarylbimidazole, and modified mica flakes evenly, stir at 10°C and 100 r / min for 12 minutes, add isophorone diamine, and adjust the viscosity to 300 MPa·s with acetone to prepare a flame retardant and corrosion-resistant coating.

[0038] Example 2:

[0039] A method for preparing a flame retardant and corrosion resistant coating, comprising the following steps:

[0040] (1) 2-chlorobenzaldehyde and 4,4'-dihydroxybenzil were added to acetic acid (9 times the mass of 2-chlorobenzaldehyde) in a molar ratio of 1:1, and ammonium acetate (0.04 times the mass of 2-chlorobenzaldehyde) was added. The mixture was stirred at 89°C and 250 r / min for 11 hours under nitrogen protection, and dried at 75°C for 7.5 hours under vacuum conditions to obtain triphenylimidazole. Potassium ferrocyanide, sodium hydroxide, and deionized water were mixed at a mass ratio of 1:1.3:16 to prepare a catalyst solution. Triphenylimidazole and dichloromethane were mixed at a mass ratio of 1:35, and stirred at 250 r / min under light-proof conditions at 10 The catalyst solution of 4.5 times the mass of triphenylimidazole was added dropwise at a uniform rate within 1 minute. After the addition was completed, the mixture was stirred and reacted for 11 hours at room temperature and pressure in the dark, and dried at 75°C under vacuum for 9 hours to obtain hexaarylbiimidazole; hexaarylbiimidazole and epichlorohydrin were added in a molar ratio of 1:4 to N,N-dimethylformamide of 13 times the mass of hexaarylbiimidazole, and a 10% sodium hydroxide aqueous solution of 2.1 times the mass of hexaarylbiimidazole was added. The mixture was stirred and reacted at 81°C and 250 r / min under nitrogen protection for 4.5 hours, and dried at 65°C under vacuum for 9 hours to obtain epoxidized hexaarylbiimidazole;

[0041] (2) 4,6-di(phenyl)-2-prop-2-enyl-1,3-dioxa-2-phosphacyclohexane 2-oxide, 1-vinyl-3-chloromethyl-1,1,3,3-tetramethyldisiloxane, azobisisobutyronitrile and toluene were mixed in a mass ratio of 1:2.1:0.04:40 to prepare a polymerizable coating reaction solution; mica flakes and a polymerizable coating reaction solution accounting for 1 / 5 of the total mass of the polymerizable coating reaction solution were mixed in a mass ratio of 1:22, stirred at 75°C and 250 r / min for 65 minutes, and the remaining The remaining polymerizable coating reaction liquid was stirred and reacted for 2.5 hours, cooled to room temperature, filtered, washed with anhydrous ethanol 4 times, and dried at 75°C for 9 hours under vacuum conditions to obtain pre-modified mica sheets; the pre-modified mica sheets, 3-aminopropyltriethoxysilane, triethylamine, and tetrahydrofuran were mixed uniformly in a mass ratio of 1:2.5:0.04:21, stirred at 55°C and 250r / min for 2.5 hours, filtered, washed with anhydrous ethanol and deionized water 4 times each, and dried at 75°C for 9 hours under vacuum conditions to obtain modified mica sheets;

[0042] (3) Allylamine and 4'-[4-(bromomethyl)phenyl]-2,2':6',2"-terpyridine were added in a molar ratio of 1:1 to N,N-dimethylformamide (11 times the mass of allylamine), and triethylamine (0.04 times the mass of allylamine) was added. The mixture was stirred at 45°C and 250 r / min for 3.5 h, and dried at 55°C under vacuum for 9 h to obtain allyl terpyridine. Allyl terpyridine, benzoyl peroxide, and n-butanol were added in a molar ratio of 1:0 .03:7.5 to prepare a monomer reaction liquid; epoxy resin E44, ethylene glycol monobutyl ether, and n-butanol were mixed evenly in a mass ratio of 1:1.5:3.5, placed in a high-pressure reactor, stirred at 104°C and 110r / min for 20 minutes, and the monomer reaction liquid 1.3 times the mass of epoxy resin E44 was added dropwise at a uniform rate over 18 minutes. The temperature was raised to 121°C, and the stirring reaction was continued for 2.5 hours. The modified epoxy resin was dried at 55°C under vacuum conditions for 11 hours to prepare the modified epoxy resin;

[0043] (4) Weigh 80 parts of modified epoxy resin, 20 parts of epoxidized hexaarylbimidazole, 4.5 parts of modified mica flakes, and 19 parts of isophorone diamine by mass; mix the modified epoxy resin, epoxidized hexaarylbimidazole, and modified mica flakes evenly, stir at 20°C, 150 r / min for 11 minutes, add isophorone diamine, and adjust the viscosity to 350 MPa·s with acetone to prepare a flame retardant and corrosion-resistant coating.

[0044] Example 3:

[0045] A method for preparing a flame retardant and corrosion resistant coating, comprising the following steps:

[0046] (1) 2-chlorobenzaldehyde and 4,4'-dihydroxybenzil were added to acetic acid with a molar ratio of 1:1, and ammonium acetate with a molar ratio of 0.05 times that of 2-chlorobenzaldehyde was added. The mixture was stirred at 90°C and 300 r / min for 10 h under nitrogen protection, and dried at 80°C for 7 h under vacuum to obtain triphenylimidazole. Potassium ferrocyanide, sodium hydroxide and deionized water were mixed at a mass ratio of 1:1.4:17 to prepare a catalyst solution. Triphenylimidazole and dichloromethane were mixed at a mass ratio of 1:40, and stirred at 300 r / min under light-proof conditions. A catalyst solution 5 times the mass of triphenylimidazole was added dropwise at a uniform rate within 10 minutes. After the addition was completed, the mixture was stirred and reacted for 10 hours at room temperature and pressure in the dark, and dried at 80°C for 8 hours under vacuum conditions to obtain hexaarylbiimidazole. Hexaarylbiimidazole and epichlorohydrin were added in a molar ratio of 1:4 to N,N-dimethylformamide 14 times the mass of hexaarylbiimidazole, and a 10% sodium hydroxide aqueous solution 2.2 times the mass of hexaarylbiimidazole was added. The mixture was stirred and reacted at 82°C and 300 r / min under nitrogen protection for 4 hours. The mixture was dried at 70°C for 8 hours under vacuum conditions to obtain epoxidized hexaarylbiimidazole.

[0047] (2) 4,6-di(phenyl)-2-prop-2-enyl-1,3-dioxa-2-phosphacyclohexane 2-oxide, 1-vinyl-3-chloromethyl-1,1,3,3-tetramethyldisiloxane, azobisisobutyronitrile and toluene were mixed evenly in a mass ratio of 1:2.2:0.05:42 to prepare a polymerizable coating reaction solution; mica sheets and the polymerizable coating reaction solution accounting for 1 / 5 of the total mass of the polymerizable coating reaction solution were mixed evenly in a mass ratio of 1:24, and stirred at 80°C and 300 r / min for 60 minutes. The remaining polymerizable coating reaction liquid was added, and the mixture was stirred and reacted for 2 hours. The mixture was cooled to room temperature, filtered, washed with anhydrous ethanol 5 times, and dried at 80°C for 8 hours under vacuum conditions to obtain pre-modified mica sheets. The pre-modified mica sheets, 3-aminopropyltriethoxysilane, triethylamine, and tetrahydrofuran were mixed uniformly in a mass ratio of 1:3:0.05:22, stirred and reacted at 60°C and 300 r / min for 2 hours, filtered, washed with anhydrous ethanol and deionized water 5 times each, and dried at 80°C for 8 hours under vacuum conditions to obtain modified mica sheets.

[0048] (3) Allylamine and 4'-[4-(bromomethyl)phenyl]-2,2':6',2"-terpyridine were added in a molar ratio of 1:1 to N,N-dimethylformamide (12 times the mass of allylamine), and triethylamine (0.05 times the mass of allylamine) was added. The mixture was stirred at 50°C and 300 r / min for 3 h, and dried at 60°C under vacuum for 8 h to obtain allyl terpyridine. Allyl terpyridine, benzoyl peroxide, and n-butanol were added in a mass ratio of 1:1 to obtain 1,2-dimethylformamide. 1:0.04:8 were mixed to prepare a monomer reaction liquid; epoxy resin E44, ethylene glycol monobutyl ether, and n-butanol were mixed in a mass ratio of 1:2:4, placed in a high-pressure reactor, stirred at 106°C and 120r / min for 15 minutes, and the monomer reaction liquid 1.4 times the mass of epoxy resin E44 was added dropwise at a constant speed over 18 minutes. The temperature was raised to 122°C, and the stirring reaction was continued for 2 hours. The modified epoxy resin was dried at 60°C under vacuum conditions for 10 hours to prepare the modified epoxy resin;

[0049] (4) Weigh 82 parts of modified epoxy resin, 23 parts of epoxidized hexaarylbimidazole, 5 parts of modified mica flakes, and 20 parts of isophorone diamine by mass; mix the modified epoxy resin, epoxidized hexaarylbimidazole, and modified mica flakes evenly, stir at 30°C and 200 r / min for 10 min, add isophorone diamine, and adjust the viscosity to 400 mPa·s with acetone to prepare a flame retardant and corrosion-resistant coating.

[0050] Comparative Example 1:

[0051] The preparation method of the flame-retardant and corrosion-resistant coating of Comparative Example 1 differs from that of Example 2 in that step (1) is omitted and step (4) is modified as follows: 80 parts by mass of modified epoxy resin, 20 parts by mass of epoxy resin E44, 4.5 parts by mass of modified mica flakes, and 19 parts by mass of isophorone diamine are weighed; the modified epoxy resin, epoxy resin E44, and modified mica flakes are uniformly mixed, stirred at 20° C. and 150 rpm for 11 minutes, isophorone diamine is added, and the viscosity is adjusted to 350 MPa·s with acetone to prepare a flame-retardant and corrosion-resistant coating. The remaining steps are the same as those of Example 2.

[0052] Comparative Example 2:

[0053] The preparation method of the flame-retardant and corrosion-resistant coating of Comparative Example 2 differs from that of Example 2 in step (2). Step (2) is modified as follows: 4,6-di(phenyl)-2-prop-2-enyl-1,3-dioxa-2-phosphacyclohexane 2-oxide, 1-vinyl-3-chloromethyl-1,1,3,3-tetramethyldisiloxane, azobisisobutyronitrile, and toluene are uniformly mixed in a mass ratio of 1:2.1:0.04:40 to prepare a polymerizable coating reaction solution; mica flakes and the polymerizable coating reaction solution, which accounts for 1 / 5 of the total mass of the polymerizable coating reaction solution, are uniformly mixed in a mass ratio of 1:22, stirred at 75°C and 250 r / min for 65 minutes, the remaining polymerizable coating reaction solution is added, and the reaction is continued with stirring for 2.5 hours. The mixture is cooled to room temperature, filtered, washed four times with anhydrous ethanol, and dried at 75°C under vacuum for 9 hours to prepare a modified mica flake. The remaining steps are the same as those of Example 2.

[0054] Comparative Example 3:

[0055] The method for preparing the flame-retardant and corrosion-resistant coating of Comparative Example 3 differs from that of Example 2 in that step (2) is omitted and step (4) is modified as follows: 80 parts by mass of a modified epoxy resin, 20 parts by mass of epoxidized hexaarylbiimidazole, 4.5 parts by mass of mica flakes, and 19 parts by mass of isophorone diamine are weighed; the modified epoxy resin, epoxidized hexaarylbiimidazole, and mica flakes are uniformly mixed, stirred at 20° C. and 150 rpm for 11 minutes, isophorone diamine is added, and the viscosity is adjusted to 350 MPa·s with acetone to prepare a flame-retardant and corrosion-resistant coating. The remaining steps are the same as those of Example 2.

[0056] Comparative Example 4:

[0057] The preparation method of the flame-retardant and corrosion-resistant coating of Comparative Example 4 differs from that of Example 2 in that step (3) is omitted and step (4) is modified as follows: 80 parts of epoxy resin E44, 20 parts of epoxidized hexaarylbiimidazole, 4.5 parts of modified mica flakes, and 19 parts of isophorone diamine are weighed, by mass; the epoxy resin E44, epoxidized hexaarylbiimidazole, and modified mica flakes are uniformly mixed, stirred at 20° C. and 150 r / min for 11 min, isophorone diamine is added, and the viscosity is adjusted to 350 MPa·s with acetone to prepare a flame-retardant and corrosion-resistant coating. The remaining steps are the same as those of Example 2.

[0058] Test Example 1

[0059] Corrosion resistance test

[0060] Test Method: The substrate material was ordinary tinplate steel plate, measuring 150 mm × 70 mm × 0.8 mm. The coatings of Example and Comparative Example were evenly coated on the surface of the tinplate steel plate to a thickness of 80 μm. The samples were dried at 50°C for 2 hours and allowed to stand at room temperature for 10 hours to prepare samples. The samples were subjected to an acetic acid salt spray test according to GB / T 10125. After 240 hours, the surface corrosion of the coatings was observed. The results are shown in Table 1.

[0061] Table 1

[0062] 240h ​​salt spray resistance 240h ​​salt spray resistance Example 1 No abnormality in paint film Comparative Example 1 No abnormality in paint film Example 2 No abnormality in paint film Comparative Example 2 Paint film blistering Example 3 No abnormality in paint film Comparative Example 3 Paint film blistering and cracking Comparative Example 4 Paint film blistering and cracking

[0063] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 4 in Table 1, it can be found that the flame retardant and corrosion resistant coating prepared by the present invention has good corrosion resistance.

[0064] By comparison, the paint films of Examples 1 to 3 are intact, while the paint films of Comparative Examples 2 to 3 have blistering and cracking phenomena, and the corrosion phenomenon of Comparative Example 3 is more serious, indicating that 4,6-di(phenyl)-2-prop-2-enyl-1,3-dioxa-2-phosphacyclohexane 2-oxide and 1-vinyl-3-chloromethyl-1,1,3,3-tetramethyldisiloxane are polymerized and coated on mica sheets to prepare pre-modified mica sheets, and chlorine atoms are introduced into the pre-modified mica sheets; the chlorine atoms introduced into the pre-modified mica sheets react with the amino groups on 3-aminopropyltriethoxysilane to prepare modified mica sheets; triethoxysilane is introduced into the modified mica sheets, and when the coating encounters the erosion of corrosive substances, triethoxysilane Oxysilane is hydrolyzed into Si-OH, which forms hydrogen bonds with hydroxyl groups on the surface of metal materials and is adsorbed on the surface of metal materials, thereby improving the adhesion between the coating and the metal material, thereby improving the corrosion resistance of the flame-retardant and corrosion-resistant coating; mica flakes have a lamellar structure, and dispersing mica flakes in the coating can form a physical barrier, extend the diffusion path of penetrating molecules, enhance the barrier ability of the coating, isolate the penetration of gas and liquid, and improve corrosion resistance; however, mica flakes are inorganic materials, and have poor compatibility when directly added to the coating and are easy to agglomerate. The surface of the mica flakes is modified so that the mica flakes are evenly dispersed in the coating, fully exerting the barrier effect, and further improving the corrosion resistance of the flame-retardant and corrosion-resistant coating.

[0065] By comparison, the paint films of Examples 1 to 3 are intact, while the paint film of Comparative Example 4 exhibits blistering and cracking, indicating that allyl terpyridine is prepared by reacting allylamine and 4'-[4-(bromomethyl)phenyl]-2,2':6',2"-terpyridine; although the epoxy resin does not have an unsaturated double bond, it contains an ether bond. The α-H atoms on the ortho-carbon and the H atoms on the tertiary carbon atoms are relatively active and can form free radicals under the action of an initiator, thereby initiating a graft polymerization reaction; allyl terpyridine is grafted onto the side chain of the epoxy resin molecule to prepare a modified epoxy resin; the modified epoxy resin participates in the curing of the coating, and a terpyridine structure is introduced into the coating. The terpyridine structure is a strong ligand for transition metal ions and can complex with metal ions generated during the corrosion process to form a protective complex product on the metal surface, thereby delaying corrosion and further improving the corrosion resistance of the flame-retardant and corrosion-resistant coating.

[0066] Test Example 2

[0067] Flame retardant performance test

[0068] Testing Method: The examples and comparative examples were poured into a polytetrafluoroethylene mold, held at 50°C for 2 hours, cooled to room temperature, and allowed to stand for 10 hours. The molds were then removed and standard bars were prepared according to GB / T 2048. The limiting oxygen index of the examples and comparative examples was then measured. The results are shown in Table 2.

[0069] Table 2

[0070]

[0071]

[0072] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 4 in Table 2, it can be found that the flame retardant and corrosion resistant coating prepared by the present invention has good flame retardant properties.

[0073] By comparison, the limiting oxygen index of Examples 1 to 3 is greater than that of Comparative Example 2, indicating that 4,6-di(phenyl)-2-prop-2-enyl-1,3-dioxa-2-phosphacyclohexane 2-oxide and 1-vinyl-3-chloromethyl-1,1,3,3-tetramethyldisiloxane are polymerized and coated on mica sheets to prepare pre-modified mica sheets, and phosphorus elements and Si-O-Si bonds are introduced into the pre-modified mica sheets; the introduction of phosphorus elements and Si-O-Si bonds can improve the flame retardant properties of flame retardant and corrosion-resistant coatings.

[0074] Test Example 3

[0075] Self-healing performance testing

[0076] Test method: The examples and comparative examples were poured into a polytetrafluoroethylene mold, held at 50°C for 2 hours, cooled to room temperature, and allowed to stand for 10 hours. The mold was then removed and the samples were prepared into standard bars according to GB / T 1040-92. The tensile strength (X) of the bars was tested. A 2mm deep, 20mm long crack was made in the middle of the standard bars, which were then irradiated with a xenon lamp for 30 minutes. The bars were then allowed to stand at room temperature in the dark for 10 hours to obtain the repaired bars. The tensile strength (Y) of the bars was then tested, and the self-healing rate of the samples was calculated as (Y / X) × 100%. The results are shown in Table 3.

[0077] Table 3

[0078]

[0079]

[0080] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 4 in Table 3, it can be found that the flame retardant and corrosion resistant coating prepared by the present invention has good self-repairing performance.

[0081] By comparison, the self-repair rates of Examples 1 to 3 are greater than that of Comparative Example 1, indicating that triphenylimidazole is prepared by reacting 2-chlorobenzaldehyde and 4,4'-dihydroxybenzil; triphenylimidazole is oxidized to obtain hexaarylbiimidazole; hexaarylbiimidazole and epichlorohydrin are reacted to obtain epoxidized hexaarylbiimidazole; the epoxy group on the epoxidized hexaarylbiimidazole can participate in the curing process of the coating, introducing a hexaarylbiimidazole structure into the coating; the hexaarylbiimidazole structure has a photoisomerization phenomenon. Under the action of ultraviolet light, the CN bond dynamically dissociates into two triphenylimidazole free radicals. Under light-proof and room temperature conditions, the free radicals collide with each other and recombine to form new CN bonds, thereby giving the flame-retardant and corrosion-resistant coating the ability to respond to ultraviolet light and self-repair.

[0082] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A flame retardant and corrosion resistant coating, characterized in that: The flame retardant and corrosion resistant coating is prepared by reacting hexaarylbiimidazole and epichlorohydrin to obtain epoxidized hexaarylbiimidazole; The modified mica flakes are prepared by reacting pre-modified mica flakes with 3-aminopropyltriethoxysilane; the modified epoxy resin is prepared by reacting epoxy resin with allyl terpyridine; and the modified epoxy resin, epoxidized hexaarylbiimidazole, modified mica flakes, isophorone diamine and acetone are uniformly mixed to prepare the modified epoxy resin; The hexaarylbiimidazole is prepared by oxidizing triphenylimidazole; The triphenylimidazole is prepared by reacting 2-chlorobenzaldehyde and 4,4'-dihydroxybenzil; The pre-modified mica sheet is prepared by polymerizing and coating 4,6-di(phenyl)-2-prop-2-enyl-1,3-dioxa-2-phosphacyclohexane 2-oxide and 1-vinyl-3-chloromethyl-1,1,3,3-tetramethyldisiloxane on a mica sheet; The allyl terpyridine is prepared by reacting allylamine and 4'-[4-(bromomethyl)phenyl]-2,2':6',2"-terpyridine.

2. A method for preparing a flame retardant and corrosion resistant coating, characterized in that: The preparation method of the flame retardant and corrosion resistant coating comprises the following preparation steps: (1) Hexaarylbiimidazole and epichlorohydrin are added in a molar ratio of 1:4 to N,N-dimethylformamide (12 to 14 times the mass of hexaarylbiimidazole), and a 10% sodium hydroxide aqueous solution (2 to 2.2 times the mass of hexaarylbiimidazole) is added. The mixture is stirred at 80 to 82°C and 200 to 300 r / min for 4 to 5 hours under nitrogen protection, and dried at 60 to 70°C for 8 to 10 hours under vacuum conditions to obtain epoxidized hexaarylbiimidazole. (2) pre-modified mica flakes, 3-aminopropyltriethoxysilane, triethylamine, and tetrahydrofuran were mixed uniformly in a mass ratio of 1:(2-3):(0.03-0.05):(20-22), stirred at 50-60°C and 200-300 r / min for 2-3 h, filtered, washed with anhydrous ethanol and deionized water 3-5 times each, and dried at 70-80°C under vacuum conditions for 8-10 h to obtain modified mica flakes; (3) Allyl terpyridine, benzoyl peroxide, and n-butanol are mixed uniformly in a mass ratio of 1:(0.02-0.04):(7-8) to prepare a monomer reaction liquid; epoxy resin, ethylene glycol monobutyl ether, and n-butanol are mixed uniformly in a mass ratio of 1:(1-2):(3-4), placed in a high-pressure reactor, stirred at 102-106°C and 100-120 r / min for 15-25 minutes, and the monomer reaction liquid of 1.2-1.4 times the mass of the epoxy resin is added dropwise at a uniform rate within 18 minutes, the temperature is raised to 120-122°C, the stirring reaction is continued for 2-3 hours, and dried at 50-60°C under vacuum conditions for 10-12 hours to obtain a modified epoxy resin; (4) Weigh 78-82 parts of modified epoxy resin, 17-23 parts of epoxidized hexaarylbimidazole, 4-5 parts of modified mica flakes, and 18-20 parts of isophorone diamine by mass; mix the modified epoxy resin, epoxidized hexaarylbimidazole, and modified mica flakes uniformly, stir at 10-30°C and 100-200 r / min for 10-12 minutes, add isophorone diamine, and adjust the viscosity to 300-400 MPa·s with acetone to prepare a flame retardant and corrosion resistant coating.

3. The method for preparing a flame retardant and corrosion resistant coating according to claim 2, characterized in that: The preparation method of the hexaaryl biimidazole in step (1) is as follows: triphenyl imidazole and dichloromethane are uniformly mixed in a mass ratio of 1: (30-40), and a catalyst solution 4 to 5 times the mass of triphenyl imidazole is added dropwise at a uniform rate within 10 minutes under light-proof conditions and stirring conditions of 200 to 300 r / min. After the dropwise addition is completed, the stirring reaction is continued at room temperature and pressure in the dark for 10 to 12 hours, and the hexaaryl biimidazole is dried at 70 to 80° C. under vacuum conditions for 8 to 10 hours to obtain the hexaaryl biimidazole.

4. The method for preparing a flame retardant and corrosion resistant coating according to claim 3, characterized in that: The catalyst solution is prepared by uniformly mixing potassium ferrocyanide, sodium hydroxide and deionized water in a mass ratio of 1:(1.2-1.4):(15-17) to prepare the catalyst solution.

5. The method for preparing a flame retardant and corrosion resistant coating according to claim 3, characterized in that: The preparation method of triphenylimidazole comprises the following steps: adding 2-chlorobenzaldehyde and 4,4'-dihydroxybenzil in a molar ratio of 1:1 to acetic acid with a mass of 8 to 10 times that of 2-chlorobenzaldehyde, adding ammonium acetate with a mass of 0.03 to 0.05 times that of 2-chlorobenzaldehyde, stirring at 88 to 90° C. and 200 to 300 rpm for reaction for 10 to 12 hours under nitrogen protection, and drying at 70 to 80° C. under vacuum conditions for 7 to 8 hours to obtain triphenylimidazole.

6. The method for preparing a flame retardant and corrosion resistant coating according to claim 2, characterized in that: The preparation method of the pre-modified mica sheet described in step (2) is as follows: mica sheets and a polymerizable coating reaction liquid accounting for 1 / 5 of the total mass of the polymerizable coating reaction liquid are mixed uniformly in a mass ratio of 1:(20-24), stirred at 70-80°C and 200-300r / min for 60-70min, the remaining polymerizable coating reaction liquid is added, and the stirring reaction is continued for 2-3h, cooled to room temperature, filtered, washed with anhydrous ethanol 3-5 times, and dried at 70-80°C under vacuum conditions for 8-10h to obtain the pre-modified mica sheet.

7. The method for preparing a flame retardant and corrosion resistant coating according to claim 6, characterized in that: The preparation method of the polymerizable coating reaction liquid comprises the following steps: uniformly mixing 4,6-di(phenyl)-2-prop-2-enyl-1,3-dioxa-2-phosphacyclohexane 2-oxide, 1-vinyl-3-chloromethyl-1,1,3,3-tetramethyldisiloxane, azobisisobutyronitrile, and toluene in a mass ratio of 1:(2-2.2):(0.03-0.05):(38-42) to prepare the polymerizable coating reaction liquid.

8. The method for preparing a flame retardant and corrosion resistant coating according to claim 6, characterized in that: The particle size of the mica flakes is 800 meshes.

9. The method for preparing a flame retardant and corrosion resistant coating according to claim 2, characterized in that: The preparation method of the allyl terpyridine in step (3) is as follows: allylamine and 4'-[4-(bromomethyl)phenyl]-2,2':6',2"-terpyridine are added in a molar ratio of 1:1 to N,N-dimethylformamide (10 to 12 times the mass of allylamine), triethylamine (0.03 to 0.05 times the mass of allylamine) is added, the mixture is stirred at 40 to 50°C and 200 to 300 r / min for 3 to 4 hours, and dried at 50 to 60°C under vacuum conditions for 8 to 10 hours to obtain allyl terpyridine.

10. The method for preparing a flame retardant and corrosion resistant coating according to claim 2, characterized in that: The model of the epoxy resin in step (3) is E44.

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