Acid, alkali and salt spray resistant coating and preparation method thereof

Abstract

The present invention discloses an acid, alkali and salt spray resistant coating and a preparation method thereof, and relates to the field of coatings. When preparing the acid, alkali and salt spray resistant coating, the present invention comprises the following steps: reacting 4-imidazole formaldehyde with 3-aminopropyldimethoxymethylsilane and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and then reacting the 4-imidazole formaldehyde with hexamethyldisiloxane, octamethylcyclotetrasiloxane and 2,4,6,8-tetramethylcyclotetrasiloxane to obtain a modified polysiloxane; reacting graphene oxide with 3-aminoethylthiophene, 3-hexylthiophene and 3-allylthiophene to obtain a modified graphene; and mixing the modified graphene, 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum, a defoamer and the modified polysiloxane to obtain a component A; and using a water-based epoxy emulsion as a component B. Components A and B are mixed to obtain the acid, alkali and salt spray resistant coating. The acid-base-resistant and salt-spray-resistant coating prepared by the invention has good acid-base resistance, salt-spray resistance, flame retardancy and hydrophobicity properties.

Description

Technical Field

[0001] The present invention relates to the field of coatings, in particular to an acid, alkali and salt spray resistant coating and a preparation method thereof. Background Art

[0002] With the development of the modern economy, metal materials are widely used in daily life and national defense construction. In recent years, various processing methods for metal materials have improved their performance, but metal materials themselves are extremely susceptible to corrosion. In various applications, metals are damaged by corrosive media in the atmosphere, soil, and seawater, causing their inherent properties to change. This phenomenon is generally referred to as metal corrosion. The corrosion and damage of metal materials lead to functional loss, structural failure, and even environmental pollution. This not only affects the sustainable development of natural resources but also poses numerous safety risks to our daily lives. This phenomenon is more likely to occur in more harsh environments, such as offshore platforms, marine transportation, and infrastructure construction.

[0003] Nowadays, a variety of technologies are used to prevent metal corrosion, including electrochemical protection, surface coatings, and the manufacture of new alloys. Among these, applying an anti-corrosion coating to metal surfaces is one of the most effective and commonly used methods. This coating provides excellent corrosion protection by isolating the corrosive medium from the metal substrate. The acid-, alkali-, and salt-spray-resistant coating prepared by the present invention exhibits excellent acid-, alkali-, and salt-spray resistance, as well as flame retardancy and hydrophobicity, and has broad market prospects. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing an acid, alkali and salt spray resistant coating to solve the problems existing in the prior art.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] Disclosed is an acid, alkali, and salt spray resistant coating. The acid, alkali, and salt spray resistant coating comprises the following steps: reacting 4-imidazole formaldehyde with 3-aminopropyldimethoxymethylsilane, and then reacting the reactant with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to obtain a modified silane; reacting hexamethyldisiloxane, octamethylcyclotetrasiloxane, and 2,4,6,8-tetramethylcyclotetrasiloxane with the modified silane to obtain a modified polysiloxane; reacting graphene oxide with 3-aminoethylthiophene, and then reacting the reactant with 3-hexylthiophene and 3-allylthiophene to obtain a modified graphene; and uniformly mixing the modified graphene, 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum, a defoaming agent, and the modified polysiloxane to obtain a component A; and uniformly mixing a water-based epoxy emulsion as a component B.

[0007] A method for preparing an acid-resistant, alkali-resistant, and salt-spray-resistant coating comprises the following steps:

[0008] (1) Hexamethyldisiloxane, octamethylcyclotetrasiloxane, 2,4,6,8-tetramethylcyclotetrasiloxane, modified silane, and trifluoromethanesulfonic acid are mixed in a mass ratio of 1: (8-12): (6-8): (2-4): (0.05-0.07), stirred at 200-400 r / min at 20-30 ° C for 20-24 h under a nitrogen atmosphere, anhydrous sodium bicarbonate 2-2.4 times the mass of trifluoromethanesulfonic acid is added, stirred for 1-2 h, and then anhydrous sodium sulfate 3-4 times the mass of trifluoromethanesulfonic acid is added, and stirring is continued for 1-2 h. The mixture is filtered and the liquid is vacuum dried for 5-7 h to obtain a modified polysiloxane;

[0009] (2) Pre-modified graphene, 3-hexylthiophene, 3-allylthiophene, and anhydrous chloroform were mixed in a mass ratio of 1: (0.2~0.4): (0.1~0.2): (400~600), ultrasonicated for 10~20 min, stirred at 400~600 r / min for 10~20 min under a nitrogen atmosphere, and anhydrous ferric chloride 2~4 times the mass of the pre-modified graphene was added, stirred for 5~15 min, ice-bathed, stirred for 3~5 h, and continued to stir at room temperature for 2~3 days, filtered, and the filter residue was washed with anhydrous ethanol 3~5 times, and vacuum dried for 5~7 h to obtain modified graphene;

[0010] (3) Weigh 1-2 parts of modified graphene, 0.002-0.004 parts of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum, 0.025-0.035 parts of defoaming agent, 75-85 parts of modified polysiloxane and 90-110 parts of deionized water and mix them to prepare component A; the aqueous epoxy emulsion is component B; component A and component B are mixed in a mass ratio of 1:0.8 to prepare an acid, alkali and salt spray resistant coating.

[0011] As an optimization, the preparation method of the modified silane described in step (1) is as follows: 4-imidazolecarboxaldehyde, 3-aminopropyldimethoxymethylsilane, and anhydrous ethanol are mixed in a mass ratio of 1: (1.6~1.8): (10~20), stirred at 400~600r / min at 50~60℃ for 10~14h, and dried at 75~85℃ for 4~6h to obtain pre-modified silane; pre-modified silane and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are mixed in a mass ratio of 1: (0.7~0.9), stirred at 400~600r / min at 95~105℃ for 10~14h to obtain.

[0012] As an optimization, the preparation method of the pre-modified graphene described in step (2) is: 3-aminoethylthiophene, graphene oxide, anhydrous ethanol, and deionized water are mixed in a mass ratio of 1: (0.8~1.2): (45~55): (180~220), ultrasonicated for 10~20 minutes, stirred at 400~600 r / min at 85~95°C for 18~22 hours, filtered, and the filter cake was washed with anhydrous ethanol for 3~5 times, and vacuum dried at 55~65°C for 4~6 hours to obtain the product.

[0013] As an optimization, the preparation method of the water-based epoxy emulsion described in step (3) is as follows: diallyl bisphenol A diglycidyl ether and polyethylene glycol are mixed in a mass ratio of 1: (5~15), heated at 90~100℃ for 25~35min, heated to 175~185℃, added with potassium persulfate in an amount of 0.0003~0.0005 times the mass of diallyl bisphenol A diglycidyl ether, and stirred at 400~600r / min for 3~5h to prepare an emulsifier; diallyl bisphenol A diglycidyl ether, emulsifier, and OP-10 are mixed in a mass ratio of 1: (0.06~0.08): (0.02~0.04), stirred at 4000~5000r / min for 5~15min at 55~65℃, deionized water is added dropwise at a rate of 150ml / min, and the mixture is stopped when the solid content is 50%~60%.

[0014] As an optimization, the defoaming agent described in step (3) is AKN-3386 defoaming agent.

[0015] As an optimization, the graphene oxide is graphene oxide with a purity of 96%.

[0016] As an optimization, the polyethylene glycol described in step (4) is polyethylene glycol with an average molecular weight of 4000.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] In the preparation of the acid, alkali and salt spray resistant coating, the present invention comprises the following steps: reacting 4-imidazole formaldehyde with 3-aminopropyldimethoxymethylsilane and then reacting with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to obtain a modified silane; reacting hexamethyldisiloxane, octamethylcyclotetrasiloxane and 2,4,6,8-tetramethylcyclotetrasiloxane with the modified silane to obtain a modified polysiloxane; reacting graphene oxide with 3-aminoethylthiophene and then reacting with 3-hexylthiophene and 3-allylthiophene to obtain a modified graphene; and uniformly mixing the modified graphene, 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum, a defoaming agent and the modified polysiloxane to obtain a component A; and uniformly mixing the components A and B with a water-based epoxy emulsion as a component B to obtain the coating.

[0019] First, 4-imidazole formaldehyde is reacted with 3-aminopropyldimethoxymethylsilane and then with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to produce a modified silane. Hexamethyldisiloxane, octamethylcyclotetrasiloxane, and 2,4,6,8-tetramethylcyclotetrasiloxane are then reacted with the modified silane to produce a modified polysiloxane. The introduction of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide allows the modified polysiloxane to contain a large amount of flame-retardant monomers, which has a good charring effect during combustion. The char layer forms a dense structure on the surface of the material, inhibiting the escape of combustible gases and effectively improving the flame retardant properties of the coating. In addition, imidazole can form a nitrogen-phosphorus-silicon synergistic flame retardant with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and long silicone chains, further improving the flame retardant properties of the coating. The modified polysiloxane introduces a large number of long polysiloxane chains containing methyl groups into the coating, which has a lower surface energy and effectively improves the hydrophobic properties of the coating; the aldehyde group on 4-imidazole formaldehyde reacts with the amino group on 3-aminopropyldimethoxymethylsilane to form a latent curing structure on the modified polysiloxane. After heating and curing, a tighter cross-linked network is formed, which effectively improves the acid, alkali and salt spray resistance of the coating. The rich silicon hydrogen structure and imidazole on the modified polysiloxane can react with double bonds and epoxy resin respectively to form a complex cross-linked network, thereby increasing the cross-linking density, thereby further improving the acid, alkali and salt spray resistance of the acid, alkali and salt spray resistant coating.

[0020] Secondly, graphene oxide is reacted with 3-aminoethylthiophene and then with 3-hexylthiophene and 3-allylthiophene to obtain modified graphene. The 3-allylthiophene on the modified graphene introduces a double bond, which can react with the silicon-hydrogen structure on the polysiloxane to form a complex cross-linked network, thereby improving the acid and alkali resistance of the coating. Graphene has a flaky structure and can act as a good physical barrier, extending the diffusion path of salt spray, thereby effectively improving the salt spray resistance of the coating. DETAILED DESCRIPTION

[0021] 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.

[0022] The graphene oxide in each embodiment and comparative example is graphene oxide with a purity of 96%; the polyethylene glycol is polyethylene glycol with an average molecular weight of 4000; and the defoaming agent is AKN-3386 defoaming agent.

[0023] Example 1, a method for preparing an acid-resistant, alkali-resistant, and salt-spray-resistant coating, comprising the following steps:

[0024] (1) 4-imidazole carboxaldehyde, 3-aminopropyldimethoxymethylsilane and anhydrous ethanol were mixed in a mass ratio of 1:1.6:10, stirred at 400 r / min at 50 °C for 10 h, and dried at 75 °C for 4 h to obtain pre-modified silane; pre-modified silane and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide were mixed in a mass ratio of 1:0.7, stirred at 400 r / min at 95 °C for 10 h to obtain modified silane; hexamethyl Disiloxane, octamethylcyclotetrasiloxane, 2,4,6,8-tetramethylcyclotetrasiloxane, modified silane, and trifluoromethanesulfonic acid were mixed in a mass ratio of 1:8:6:2:0.05, stirred at 20°C and 200 r / min for 20 h under a nitrogen atmosphere, anhydrous sodium bicarbonate (2 times the mass of trifluoromethanesulfonic acid) was added, stirred for 1 h, and then anhydrous sodium sulfate (3 times the mass of trifluoromethanesulfonic acid) was added, stirred for another 1 h, filtered, and the liquid was vacuum dried for 5 h to obtain modified polysiloxane;

[0025] (2) 3-aminoethylthiophene, graphene oxide, anhydrous ethanol and deionized water were mixed in a mass ratio of 1:0.8:45:180, ultrasonicated for 10 minutes, stirred at 400 r / min at 85 ° C for 18 hours, filtered, and the filter cake was washed with anhydrous ethanol three times, and vacuum dried at 55 ° C for 4 hours to obtain pre-modified graphene; pre-modified graphene, 3-hexylthiophene, 3-allylthiophene and anhydrous chloroform were mixed in a mass ratio of 1:0.2:0.1:400, ultrasonicated for 10 minutes, stirred at 400 r / min under a nitrogen atmosphere for 10 minutes, anhydrous ferric chloride twice the mass of pre-modified graphene was added, stirred for 5 minutes, ice bathed, stirred for 3 hours, and continued to stir at room temperature for 2 days, filtered, and the filter residue was washed with anhydrous ethanol three times, and vacuum dried for 5 hours to obtain modified graphene;

[0026] (3) Diallyl bisphenol A diglycidyl ether and polyethylene glycol were mixed in a mass ratio of 1:5, heated at 90 ° C for 25 minutes, heated to 175 ° C, added with potassium persulfate 0.0003 times the mass of diallyl bisphenol A diglycidyl ether, and stirred at 400 r / min for 3 hours to prepare an emulsifier; Diallyl bisphenol A diglycidyl ether, emulsifier, and OP-10 were mixed in a mass ratio of 1:0.06:0.02, stirred at 55 ° C for 5 minutes at 4000 r / min, and deionized water was added dropwise at a rate of 150 ml / min. The mixture was stopped when the solid content reached 50%, and a water-based epoxy emulsion was prepared;

[0027] (4) Weigh 1 part of modified graphene, 0.002 parts of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum, 0.025 parts of defoaming agent, 75 parts of modified polysiloxane and 90 parts of deionized water and mix them to prepare component A; the aqueous epoxy emulsion is component B; component A and component B are mixed in a mass ratio of 1:0.8 to prepare an acid, alkali and salt spray resistant coating.

[0028] Example 2, a method for preparing an acid-resistant, alkali-resistant, and salt-spray-resistant coating, comprising the following steps:

[0029] (1) 4-imidazole carboxaldehyde, 3-aminopropyldimethoxymethylsilane and anhydrous ethanol were mixed in a mass ratio of 1:1.7:15, stirred at 500 r / min at 55 °C for 12 h, and dried at 80 °C for 5 h to obtain pre-modified silane; pre-modified silane and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide were mixed in a mass ratio of 1:0.8, stirred at 50 r / min at 100 °C for 12 h to obtain modified silane; hexamethyldisiloxane, Octamethylcyclotetrasiloxane, 2,4,6,8-tetramethylcyclotetrasiloxane, modified silane, and trifluoromethanesulfonic acid were mixed in a mass ratio of 1:10:7:3:0.06, stirred at 25°C and 300 r / min for 22 h under a nitrogen atmosphere, anhydrous sodium bicarbonate (2.2 times the mass of trifluoromethanesulfonic acid) was added, stirred for 1.5 h, and then anhydrous sodium sulfate (3.5 times the mass of trifluoromethanesulfonic acid) was added, stirred for 1.5 h, filtered, and the liquid was vacuum dried for 6 h to obtain modified polysiloxane;

[0030] (2) 3-aminoethylthiophene, graphene oxide, anhydrous ethanol and deionized water were mixed in a mass ratio of 1:1:50:200, ultrasonicated for 15 minutes, stirred at 500 r / min at 90 °C for 20 hours, filtered, and the filter cake was washed with anhydrous ethanol 4 times, and vacuum dried at 60 °C for 5 hours to obtain pre-modified graphene; pre-modified graphene, 3-hexylthiophene, 3-allylthiophene and anhydrous chloroform were mixed in a mass ratio of 1:0.3:0.15:500, ultrasonicated for 15 minutes, stirred at 500 r / min under a nitrogen atmosphere for 15 minutes, anhydrous ferric chloride 3 times the mass of pre-modified graphene was added, stirred for 10 minutes, ice bathed, stirred for 4 hours, and continued to stir at room temperature for 2.5 days, filtered, and the filter residue was washed with anhydrous ethanol 4 times, and vacuum dried for 6 hours to obtain modified graphene;

[0031] (3) Diallyl bisphenol A diglycidyl ether and polyethylene glycol were mixed in a mass ratio of 1:10, heated at 95 ° C for 30 minutes, heated to 180 ° C, added with potassium persulfate 0.0004 times the mass of diallyl bisphenol A diglycidyl ether, and stirred at 500 r / min for 4 hours to prepare an emulsifier; Diallyl bisphenol A diglycidyl ether, emulsifier, and OP-10 were mixed in a mass ratio of 1:0.07:0.03, stirred at 60 ° C for 10 minutes at 4500 r / min, and deionized water was added dropwise at a rate of 150 ml / min. The mixture was stopped when the solid content reached 55%, and a water-based epoxy emulsion was prepared;

[0032] (4) Weigh 1.5 parts of modified graphene, 0.003 parts of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum, 0.03 parts of defoaming agent, 80 parts of modified polysiloxane and 100 parts of deionized water and mix them to prepare component A; the aqueous epoxy emulsion is component B; component A and component B are mixed in a mass ratio of 1:0.8 to prepare an acid, alkali and salt spray resistant coating.

[0033] Example 3, a method for preparing an acid-resistant, alkali-resistant, and salt-spray-resistant coating, comprising the following preparation steps:

[0034] (1) 4-imidazole carboxaldehyde, 3-aminopropyldimethoxymethylsilane and anhydrous ethanol were mixed in a mass ratio of 1: 1.8: 20, stirred at 600 r / min at 60 ° C for 14 h, and dried at 85 ° C for 6 h to prepare pre-modified silane; pre-modified silane and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide were mixed in a mass ratio of 1: 0.9, stirred at 105 ° C for 14 h at 600 r / min to prepare modified silane; hexamethyldisiloxane, octamethylcyclotetrasiloxane, 2,4,6,8-tetramethylcyclotetrasiloxane, modified silane and trifluoromethanesulfonic acid were mixed in a mass ratio of 1: 12: 8: 4: 0.07, and dried under nitrogen atmosphere. The mixture was stirred at 30°C and 400 rpm for 24 hours, anhydrous sodium bicarbonate (2.4 times the mass of trifluoromethanesulfonic acid) was added, and the mixture was stirred for 2 hours. Anhydrous sodium sulfate (4 times the mass of trifluoromethanesulfonic acid) was then added, and the mixture was stirred for another 2 hours. The mixture was filtered, and the liquid was vacuum dried for 7 hours to obtain a modified polysiloxane.

[0035] (2) 3-aminoethylthiophene, graphene oxide, anhydrous ethanol and deionized water were mixed in a mass ratio of 1:1.2:55:220, ultrasonicated for 20 minutes, stirred at 600 r / min at 95 °C for 22 hours, filtered, and the filter cake was washed with anhydrous ethanol 5 times, and vacuum dried at 65 °C for 6 hours to obtain pre-modified graphene; pre-modified graphene, 3-hexylthiophene, 3-allylthiophene and anhydrous chloroform were mixed in a mass ratio of 1:0.4:0.2:600, ultrasonicated for 20 minutes, stirred at 600 r / min under a nitrogen atmosphere for 20 minutes, anhydrous ferric chloride 4 times the mass of pre-modified graphene was added, stirred for 15 minutes, ice bathed, stirred for 5 hours, and continued to stir at room temperature for 3 days, filtered, and the filter residue was washed with anhydrous ethanol 5 times, and vacuum dried for 7 hours to obtain modified graphene;

[0036] (3) Diallyl bisphenol A diglycidyl ether and polyethylene glycol were mixed in a mass ratio of 1:15, heated at 100 ° C for 35 minutes, heated to 185 ° C, added with potassium persulfate 0.0005 times the mass of diallyl bisphenol A diglycidyl ether, and stirred at 600 r / min for 5 hours to prepare an emulsifier; Diallyl bisphenol A diglycidyl ether, emulsifier, and OP-10 were mixed in a mass ratio of 1:0.08:0.04, stirred at 65 ° C for 15 minutes at 5000 r / min, and deionized water was added dropwise at a rate of 150 ml / min. The mixture was stopped when the solid content reached 60%, and a water-based epoxy emulsion was prepared;

[0037] (4) Weigh 2 parts of modified graphene, 0.004 parts of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum, 0.035 parts of defoaming agent, 85 parts of modified polysiloxane and 110 parts of deionized water and mix them to prepare component A; the aqueous epoxy emulsion is component B; component A and component B are mixed in a mass ratio of 1:0.8 to prepare an acid, alkali and salt spray resistant coating.

[0038] Comparative Example 1, a method for preparing an acid-resistant, alkali-resistant, and salt-spray-resistant coating, comprising the following preparation steps:

[0039] (1) 4-imidazole formaldehyde, 3-aminopropyldimethoxymethylsilane, and anhydrous ethanol were mixed in a mass ratio of 1:1.7:15, stirred at 55°C and 500 r / min for 12 h, and dried at 80°C for 5 h to obtain pre-modified silane; hexamethyldisiloxane, octamethylcyclotetrasiloxane, 2,4,6,8-tetramethylcyclotetrasiloxane, pre-modified silane, and trifluoromethanesulfonic acid were mixed in a mass ratio of 1:10:7:3:0.06, stirred at 25°C and 300 r / min for 22 h under a nitrogen atmosphere, anhydrous sodium bicarbonate 2.2 times the mass of trifluoromethanesulfonic acid was added, stirred for 1.5 h, and then anhydrous sodium sulfate 3.5 times the mass of trifluoromethanesulfonic acid was added, and the mixture was stirred for 1.5 h. The mixture was filtered and the liquid was vacuum dried for 6 h to obtain modified polysiloxane;

[0040] (2) 3-aminoethylthiophene, graphene oxide, anhydrous ethanol and deionized water were mixed in a mass ratio of 1:1:50:200, ultrasonicated for 15 minutes, stirred at 500 r / min at 90 °C for 20 hours, filtered, and the filter cake was washed with anhydrous ethanol 4 times, and vacuum dried at 60 °C for 5 hours to obtain pre-modified graphene; pre-modified graphene, 3-hexylthiophene, 3-allylthiophene and anhydrous chloroform were mixed in a mass ratio of 1:0.3:0.15:500, ultrasonicated for 15 minutes, stirred at 500 r / min under a nitrogen atmosphere for 15 minutes, anhydrous ferric chloride 3 times the mass of pre-modified graphene was added, stirred for 10 minutes, ice bathed, stirred for 4 hours, and continued to stir at room temperature for 2.5 days, filtered, and the filter residue was washed with anhydrous ethanol 4 times, and vacuum dried for 6 hours to obtain modified graphene;

[0041] (3) Diallyl bisphenol A diglycidyl ether and polyethylene glycol were mixed in a mass ratio of 1:10, heated at 95 ° C for 30 minutes, heated to 180 ° C, added with potassium persulfate 0.0004 times the mass of diallyl bisphenol A diglycidyl ether, and stirred at 500 r / min for 4 hours to prepare an emulsifier; Diallyl bisphenol A diglycidyl ether, emulsifier, and OP-10 were mixed in a mass ratio of 1:0.07:0.03, stirred at 60 ° C for 10 minutes at 4500 r / min, and deionized water was added dropwise at a rate of 150 ml / min. The mixture was stopped when the solid content reached 55%, and a water-based epoxy emulsion was prepared;

[0042] (4) Weigh 1.5 parts of modified graphene, 0.003 parts of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum, 0.03 parts of defoaming agent, 80 parts of modified polysiloxane and 100 parts of deionized water and mix them to prepare component A; the aqueous epoxy emulsion is component B; component A and component B are mixed in a mass ratio of 1:0.8 to prepare an acid, alkali and salt spray resistant coating.

[0043] Comparative Example 2, a method for preparing an acid-resistant, alkali-resistant, and salt-spray-resistant coating, comprising the following preparation steps:

[0044] (1) Hexamethyldisiloxane, octamethylcyclotetrasiloxane, 2,4,6,8-tetramethylcyclotetrasiloxane, and trifluoromethanesulfonic acid were mixed in a mass ratio of 1:10:7:0.06, stirred at 25°C and 300 r / min for 22 h under a nitrogen atmosphere, anhydrous sodium bicarbonate (2.2 times the mass of trifluoromethanesulfonic acid) was added, stirred for 1.5 h, and then anhydrous sodium sulfate (3.5 times the mass of trifluoromethanesulfonic acid) was added, stirred for 1.5 h, filtered, and the liquid was vacuum dried for 6 h to obtain modified polysiloxane;

[0045] (2) 3-aminoethylthiophene, graphene oxide, anhydrous ethanol and deionized water were mixed in a mass ratio of 1:1:50:200, ultrasonicated for 15 minutes, stirred at 500 r / min at 90 °C for 20 hours, filtered, and the filter cake was washed with anhydrous ethanol 4 times, and vacuum dried at 60 °C for 5 hours to obtain pre-modified graphene; pre-modified graphene, 3-hexylthiophene, 3-allylthiophene and anhydrous chloroform were mixed in a mass ratio of 1:0.3:0.15:500, ultrasonicated for 15 minutes, stirred at 500 r / min under a nitrogen atmosphere for 15 minutes, anhydrous ferric chloride 3 times the mass of pre-modified graphene was added, stirred for 10 minutes, ice bathed, stirred for 4 hours, and continued to stir at room temperature for 2.5 days, filtered, and the filter residue was washed with anhydrous ethanol 4 times, and vacuum dried for 6 hours to obtain modified graphene;

[0046] (3) Diallyl bisphenol A diglycidyl ether and polyethylene glycol were mixed in a mass ratio of 1:10, heated at 95 ° C for 30 minutes, heated to 180 ° C, added with potassium persulfate 0.0004 times the mass of diallyl bisphenol A diglycidyl ether, and stirred at 500 r / min for 4 hours to prepare an emulsifier; Diallyl bisphenol A diglycidyl ether, emulsifier, and OP-10 were mixed in a mass ratio of 1:0.07:0.03, stirred at 60 ° C for 10 minutes at 4500 r / min, and deionized water was added dropwise at a rate of 150 ml / min. The mixture was stopped when the solid content reached 55%, and a water-based epoxy emulsion was prepared;

[0047] (4) Weigh 1.5 parts of modified graphene, 0.003 parts of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum, 0.03 parts of defoaming agent, 80 parts of modified polysiloxane and 100 parts of deionized water and mix them to prepare component A; the aqueous epoxy emulsion is component B; component A and component B are mixed in a mass ratio of 1:0.8 to prepare an acid, alkali and salt spray resistant coating.

[0048] Comparative Example 3, a method for preparing an acid-resistant, alkali-resistant, and salt-spray-resistant coating, comprising the following preparation steps:

[0049] (1) 3-aminoethylthiophene, graphene oxide, anhydrous ethanol and deionized water were mixed in a mass ratio of 1:1:50:200, ultrasonicated for 15 minutes, stirred at 500 r / min at 90 °C for 20 hours, filtered, and the filter cake was washed with anhydrous ethanol 4 times, and vacuum dried at 60 °C for 5 hours to obtain pre-modified graphene; pre-modified graphene, 3-hexylthiophene, 3-allylthiophene and anhydrous chloroform were mixed in a mass ratio of 1:0.3:0.15:500, ultrasonicated for 15 minutes, stirred at 500 r / min under a nitrogen atmosphere for 15 minutes, anhydrous ferric chloride 3 times the mass of pre-modified graphene was added, stirred for 10 minutes, ice-bathed, stirred for 4 hours, and continued to stir at room temperature for 2.5 days, filtered, and the filter residue was washed with anhydrous ethanol 4 times, and vacuum dried for 6 hours to obtain modified graphene;

[0050] (2) Diallyl bisphenol A diglycidyl ether and polyethylene glycol were mixed in a mass ratio of 1:10, heated at 95 ° C for 30 minutes, heated to 180 ° C, added with potassium persulfate 0.0004 times the mass of diallyl bisphenol A diglycidyl ether, and stirred at 500 r / min for 4 hours to prepare an emulsifier; Diallyl bisphenol A diglycidyl ether, emulsifier, and OP-10 were mixed in a mass ratio of 1:0.07:0.03, stirred at 60 ° C for 10 minutes at 4500 r / min, and deionized water was added dropwise at a rate of 150 ml / min. The mixture was stopped when the solid content reached 55%, and a water-based epoxy emulsion was prepared;

[0051] (3) Weigh 1.5 parts of modified graphene, 0.003 parts of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum, 0.03 parts of defoaming agent, 5 parts of ethylenediamine and 100 parts of deionized water and mix them to prepare component A; the water-based epoxy emulsion is component B; component A and component B are mixed in a mass ratio of 1:0.8 to prepare an acid, alkali and salt spray resistant coating.

[0052] Comparative Example 4, a method for preparing an acid-resistant, alkali-resistant, and salt-spray-resistant coating, comprising the following preparation steps:

[0053] (1) 4-imidazole carboxaldehyde, 3-aminopropyldimethoxymethylsilane and anhydrous ethanol were mixed in a mass ratio of 1:1.7:15, stirred at 500 r / min at 55 °C for 12 h, and dried at 80 °C for 5 h to obtain pre-modified silane; pre-modified silane and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide were mixed in a mass ratio of 1:0.8, stirred at 50 r / min at 100 °C for 12 h to obtain modified silane; hexamethyldisiloxane, Octamethylcyclotetrasiloxane, 2,4,6,8-tetramethylcyclotetrasiloxane, pre-modified silane, and trifluoromethanesulfonic acid were mixed in a mass ratio of 1:10:7:3:0.06, stirred at 25°C and 300 r / min for 22 h under a nitrogen atmosphere, anhydrous sodium bicarbonate (2.2 times the mass of trifluoromethanesulfonic acid) was added, stirred for 1.5 h, and then anhydrous sodium sulfate (3.5 times the mass of trifluoromethanesulfonic acid) was added, stirred for 1.5 h, filtered, and the liquid was vacuum dried for 6 h to obtain modified polysiloxane;

[0054] (2) Diallyl bisphenol A diglycidyl ether and polyethylene glycol were mixed in a mass ratio of 1:10, heated at 95 ° C for 30 minutes, heated to 180 ° C, added with potassium persulfate 0.0004 times the mass of diallyl bisphenol A diglycidyl ether, and stirred at 500 r / min for 4 hours to prepare an emulsifier; Diallyl bisphenol A diglycidyl ether, emulsifier, and OP-10 were mixed in a mass ratio of 1:0.07:0.03, stirred at 60 ° C for 10 minutes at 4500 r / min, and deionized water was added dropwise at a rate of 150 ml / min. The mixture was stopped when the solid content reached 55%, and a water-based epoxy emulsion was prepared;

[0055] (3) Weigh 1.5 parts of graphene, 0.003 parts of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum, 0.03 parts of defoaming agent, 80 parts of modified polysiloxane and 100 parts of deionized water and mix them to prepare component A; water-based epoxy emulsion is component B; component A and component B are mixed in a mass ratio of 1:0.8 to prepare an acid, alkali and salt spray resistant coating.

[0056] Comparative Example 5, a method for preparing an acid-resistant, alkali-resistant, and salt-spray-resistant coating, comprising the following preparation steps:

[0057] (1) 4-imidazole carboxaldehyde, 3-aminopropyldimethoxymethylsilane and anhydrous ethanol were mixed in a mass ratio of 1:1.7:15, stirred at 500 r / min at 55 °C for 12 h, and dried at 80 °C for 5 h to obtain pre-modified silane; pre-modified silane and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide were mixed in a mass ratio of 1:0.8, stirred at 50 r / min at 100 °C for 12 h to obtain modified silane; hexamethyldisiloxane, Octamethylcyclotetrasiloxane, 2,4,6,8-tetramethylcyclotetrasiloxane, pre-modified silane, and trifluoromethanesulfonic acid were mixed in a mass ratio of 1:10:7:3:0.06, stirred at 25°C and 300 r / min for 22 h under a nitrogen atmosphere, anhydrous sodium bicarbonate (2.2 times the mass of trifluoromethanesulfonic acid) was added, stirred for 1.5 h, and then anhydrous sodium sulfate (3.5 times the mass of trifluoromethanesulfonic acid) was added, stirred for 1.5 h, filtered, and the liquid was vacuum dried for 6 h to obtain modified polysiloxane;

[0058] (2) Diallyl bisphenol A diglycidyl ether and polyethylene glycol were mixed in a mass ratio of 1:10, heated at 95 ° C for 30 minutes, heated to 180 ° C, added with potassium persulfate 0.0004 times the mass of diallyl bisphenol A diglycidyl ether, and stirred at 500 r / min for 4 hours to prepare an emulsifier; Diallyl bisphenol A diglycidyl ether, emulsifier, and OP-10 were mixed in a mass ratio of 1:0.07:0.03, stirred at 60 ° C for 10 minutes at 4500 r / min, and deionized water was added dropwise at a rate of 150 ml / min. The mixture was stopped when the solid content reached 55%, and a water-based epoxy emulsion was prepared;

[0059] (3) Weigh 0.003 parts of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum, 0.03 parts of defoaming agent, 80 parts of modified polysiloxane and 100 parts of deionized water and mix them to prepare component A; the water-based epoxy emulsion is component B; component A and component B are mixed in a mass ratio of 1:0.8 to prepare an acid, alkali and salt spray resistant coating.

[0060] Test Example 1:

[0061] Acid and alkali resistance testing: Test panels were mounted on a horizontal platform and abraded with 150-1000 grit sandpaper. The panels were then ultrasonically degreased in acetone. The prepared coating was then evenly coated on Q235 carbon steel (100 mm × 70 mm × 0.8 mm) and dried at 70°C for 48 hours. 5 wt% hydrochloric acid and 5 wt% sodium hydroxide aqueous solutions were prepared, respectively, and the test samples were immersed in the prepared acid and alkali solutions. Each set of samples consisted of three 0235 steel panels. Coating shedding was observed. The results are shown in Table 1.

[0062] Salt spray resistance test: The test plate was fixed on a horizontal platform, abraded with 150-1000 grit sandpaper, and ultrasonically degreased in acetone. The prepared coating was then evenly applied to Q235 carbon steel (100 mm × 70 mm × 0.8 mm) and dried at room temperature for 24 hours. The coatings prepared in each example and comparative example were applied to 0235 steel plates according to the formulation, dried at 70°C for 48 hours, and scratched diagonally with a knife. The edges of the test steel plates were sealed with scotch tape to prevent the infiltration of corrosive media and affect the test results. The prepared test samples were then placed in a YWX-150 salt spray test chamber for testing, and the corrosion of the scratched areas was observed. The results are shown in Table 1.

[0063] Table 1:

[0064] ;

[0065] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 5 in Table 1, it can be found that the acid, alkali and salt spray resistant coating prepared by the present invention has good acid, alkali and salt spray resistance.

[0066] By comparison, the shedding conditions of Examples 1 to 3 are better than that of Comparative Example 2, indicating that the aldehyde group on 4-imidazolecarboxaldehyde reacts with the amino group on 3-aminopropyldimethoxymethylsilane to form a latent cured structure on the modified polysiloxane. After heating and curing, a tighter cross-linked network is formed, effectively improving the acid and alkali resistance of the coating; the shedding conditions of Examples 1 to 3 are better than that of Comparative Example 3, indicating that the rich silicon hydrogen structure and imidazole on the modified polysiloxane can react with the double bond and epoxy resin respectively to form a complex cross-linked network, thereby increasing the cross-linking density and thus improving the acid and alkali resistance of the acid, alkali and salt spray resistant coating; the shedding conditions of Examples 1 to 3 are better than those of Comparative Examples 4 and 5, indicating that the 3-allylthiophene on the modified graphene introduces a double bond, which can react with the silicon hydrogen structure on the polysiloxane to form a complex cross-linked network, thereby improving the acid and alkali resistance of the coating.

[0067] By comparison, the corrosion conditions of Examples 1 to 3 are better than that of Comparative Example 2, indicating that the aldehyde group on 4-imidazolecarboxaldehyde reacts with the amino group on 3-aminopropyldimethoxymethylsilane to form a latent cured structure on the modified polysiloxane. After heat curing, a tighter cross-linked network is formed, effectively improving the salt spray resistance of the coating; the corrosion conditions of Examples 1 to 3 are better than that of Comparative Example 3, indicating that the rich silicon hydrogen structure and imidazole on the modified polysiloxane can react with the double bond and epoxy resin, respectively, to form a complex cross-linked network, thereby increasing the cross-linking density and thus improving the salt spray resistance of the acid, alkali and salt spray resistant coating; the corrosion conditions of Examples 1 to 3 are better than that of Comparative Example 5, indicating that graphene has a flaky structure, which can play a good physical barrier effect, extend the diffusion path of salt spray, and thus effectively improve the salt spray resistance of the coating.

[0068] Test Example 2:

[0069] Flame retardant performance test: Samples of the fast-drying waterborne epoxy coatings prepared in the embodiments and test examples were prepared according to GB / T2406 and tested for limiting oxygen index. The results are shown in Table 2.

[0070] Table 2:

[0071] ;

[0072] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 5 in Table 2, it can be found that the acid, alkali and salt spray 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 significantly greater than that of Comparative Example 1, indicating that the modified silane is prepared by reacting 4-imidazolecarboxaldehyde with 3-aminopropyldimethoxymethylsilane and then with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide; the modified polysiloxane is prepared by reacting hexamethyldisiloxane, octamethylcyclotetrasiloxane, and 2,4,6,8-tetramethylcyclotetrasiloxane with the modified silane, and the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is prepared. -The introduction of oxide makes the modified polysiloxane contain a large amount of flame retardant monomers, which has a good effect of promoting carbonization during combustion. The carbon layer forms a dense structure on the surface of the material, inhibits the escape of combustible gas, and effectively improves the flame retardant properties of the coating; the limiting oxygen index of Examples 1 to 3 is significantly greater than the limiting oxygen index of Comparative Examples 2 and 3, indicating that imidazole can form nitrogen-phosphorus-silicon synergistic flame retardancy with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and long chains of organic silicon, thereby improving the flame retardant properties of the coating.

[0074] Test Example 3:

[0075] Hydrophobicity test: The coatings prepared in each embodiment and comparative example were cut into 100 mm × 100 mm samples, and the static contact angle of water was measured using an SL200A contact angle meter. The results are shown in Table 3.

[0076] Table 3:

[0077] ;

[0078] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 5 in Table 3, it can be found that the acid, alkali and salt spray resistant coating prepared by the present invention has good hydrophobicity.

[0079] By comparison, the contact angles of Examples 1 to 3 are significantly greater than the contact angle of Comparative Example 3, indicating that 4-imidazolecarboxaldehyde is reacted with 3-aminopropyldimethoxymethylsilane and then with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to prepare a modified silane; hexamethyldisiloxane, octamethylcyclotetrasiloxane, and 2,4,6,8-tetramethylcyclotetrasiloxane are reacted with the modified silane to prepare a modified polysiloxane, and a large amount of long polysiloxane chains containing methyl groups are introduced into the coating, which has a lower surface energy and effectively improves the hydrophobic properties of the coating.

[0080] 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. An acid, alkali and salt spray resistant coating, characterized in that: The acid, alkali and salt spray resistant coating is prepared by uniformly mixing modified graphene, 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum, a defoamer and a modified polysiloxane to obtain component A, and uniformly mixing component A and component B with a water-based epoxy emulsion; The modified graphene is prepared by reacting graphene oxide with 3-aminoethylthiophene and then with 3-hexylthiophene and 3-allylthiophene; The modified polysiloxane is prepared by reacting 4-imidazole formaldehyde with 3-aminopropyldimethoxymethylsilane, then with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and finally with hexamethyldisiloxane, octamethylcyclotetrasiloxane and 2,4,6,8-tetramethylcyclotetrasiloxane.

2. A method for preparing an acid-resistant, alkali-resistant, and salt-spray-resistant coating, characterized in that: The method comprises the following preparation steps: (1) Hexamethyldisiloxane, octamethylcyclotetrasiloxane, 2,4,6,8-tetramethylcyclotetrasiloxane, modified silane, and trifluoromethanesulfonic acid are mixed in a mass ratio of 1: (8-12): (6-8): (2-4): (0.05-0.07), stirred at 200-400 r / min at 20-30 ° C for 20-24 h under a nitrogen atmosphere, anhydrous sodium bicarbonate 2-2.4 times the mass of trifluoromethanesulfonic acid is added, stirred for 1-2 h, and then anhydrous sodium sulfate 3-4 times the mass of trifluoromethanesulfonic acid is added, and stirring is continued for 1-2 h. The mixture is filtered and the liquid is vacuum dried for 5-7 h to obtain a modified polysiloxane; (2) Pre-modified graphene, 3-hexylthiophene, 3-allylthiophene, and anhydrous chloroform were mixed in a mass ratio of 1: (0.2~0.4): (0.1~0.2): (400~600), ultrasonicated for 10~20 min, stirred at 400~600 r / min for 10~20 min under a nitrogen atmosphere, and anhydrous ferric chloride 2~4 times the mass of the pre-modified graphene was added, stirred for 5~15 min, ice-bathed, stirred for 3~5 h, and continued to stir at room temperature for 2~3 days, filtered, and the filter residue was washed with anhydrous ethanol 3~5 times, and vacuum dried for 5~7 h to obtain modified graphene; (3) Weigh 1-2 parts of modified graphene, 0.002-0.004 parts of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum, 0.025-0.035 parts of defoaming agent, 75-85 parts of modified polysiloxane and 90-110 parts of deionized water and mix them to prepare component A; the aqueous epoxy emulsion is component B; component A and component B are mixed in a mass ratio of 1:0.8 to prepare an acid, alkali and salt spray resistant coating.

3. The method for preparing an acid-resistant, alkali-resistant, and salt-spray-resistant coating according to claim 2, wherein: The preparation method of the modified silane described in step (1) is as follows: 4-imidazole carboxaldehyde, 3-aminopropyldimethoxymethylsilane, and anhydrous ethanol are mixed in a mass ratio of 1: (1.6-1.8): (10-20), stirred at 400-600 r / min at 50-60° C. for 10-14 hours, and dried at 75-85° C. for 4-6 hours to obtain pre-modified silane; The pre-modified silane and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are mixed in a mass ratio of 1:(0.7-0.9), and stirred at 400-600 r / min at 95-105° C. for 10-14 h to obtain the product.

4. The method for preparing an acid-resistant, alkali-resistant, and salt-spray-resistant coating according to claim 2, wherein: The preparation method of the pre-modified graphene described in step (2) is: 3-aminoethylthiophene, graphene oxide, anhydrous ethanol, and deionized water are mixed in a mass ratio of 1: (0.8~1.2): (45~55): (180~220), ultrasonicated for 10~20 minutes, stirred at 400~600 r / min at 85~95°C for 18~22 hours, filtered, and the filter cake is washed with anhydrous ethanol for 3~5 times, and vacuum dried at 55~65°C for 4~6 hours to obtain the obtained product.

5. The method for preparing an acid-resistant, alkali-resistant, and salt-spray-resistant coating according to claim 2, wherein: The preparation method of the water-based epoxy emulsion described in step (3) is as follows: diallyl bisphenol A diglycidyl ether and polyethylene glycol are mixed in a mass ratio of 1: (5~15), heated at 90~100℃ for 25~35min, heated to 175~185℃, added with potassium persulfate in an amount of 0.0003~0.0005 times the mass of diallyl bisphenol A diglycidyl ether, and stirred at 400~600r / min for 3~5h to prepare an emulsifier; diallyl bisphenol A diglycidyl ether, emulsifier, and OP-10 are mixed in a mass ratio of 1: (0.06~0.08): (0.02~0.04), stirred at 4000~5000r / min for 5~15min at 55~65℃, and deionized water is added dropwise at a rate of 150ml / min. The mixture is stopped when the solid content is 50%~60%, thereby preparing the emulsifier.

6. The method for preparing an acid-resistant, alkali-resistant, and salt-spray-resistant coating according to claim 2, wherein: The defoaming agent described in step (3) is AKN-3386 defoaming agent.