An ultrathin corrosion-resistant water-based paint and a preparation method thereof

Abstract

The present invention relates to the technical field of water-based coatings, and in particular to a kind of ultra-thin corrosion-resistant water-based coating and preparation method thereof. The above-mentioned ultra-thin corrosion-resistant water-based coating is composed of component A and component B in a mass ratio of 10: 1-2; component A raw materials include by mass: 40-60 parts of water-based epoxy emulsion, 30-50 parts of zinc powder, 1.2-3.6 parts of phosphoric acid, 1-3 parts of graphene oxide, 0.1-1 parts of γ-aminopropyltriethoxysilane, 1-2 parts of dispersant, 0.1-1 parts of defoamer, 1-3 parts of corrosion inhibitor, and 0.1-1 parts of leveling agent; component B includes by mass: 40-60 parts of curing agent, 1-3 parts of accelerator, 1-3 parts of hyperbranched polyamide amine, 5-15 parts of cosolvent, and 20-30 parts of water. The present invention is not only environmentally friendly, but also can achieve long-term corrosion resistance when ensuring ultra-thin thickness, and has good construction stability, and has significant application value in harsh environments such as ships and offshore wind power.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water-based paint, in particular to an ultra-thin corrosion-resistant water-based paint and a preparation method thereof. BACKGROUND

[0002] Traditional water-based epoxy paint generally has a contradiction between film thickness and corrosion resistance in the field of heavy-duty corrosion protection. In order to meet the long-term protection requirements, the coating thickness in the prior art usually needs to be increased to more than 200 microns. However, the over-thick coating film not only increases the material cost, but also leads to low construction efficiency, especially in the surface of complex structure, which is prone to defects such as sagging and pinholes. If thin-layer coating (<100 microns) is used, the permeability resistance and mechanical strength of the coating will be significantly reduced, and the problems such as uneven dispersion of inorganic powder and weak interfacial bonding will be further aggravated, which will cause the corrosion medium to quickly penetrate the coating and cause the substrate to rust.

[0003] The existing commercially available ultra-thin water-based paint generally has poor zinc powder dispersion stability. The conventional mechanical dispersion is difficult to achieve uniform distribution of nano-sized zinc powder, and the zinc powder accumulates in the thin layer to form a conductive path, which accelerates electrochemical corrosion. At the same time, the resin-zinc powder interface contact area of the thin-layer coating is small, and the volume shrinkage during curing is prone to produce micro-cracks, and the interface will hydrolyze in a humid and hot environment to cause the coating to peel off.

[0004] Although the existing technology can extend the medium penetration path by adding sheet-shaped fillers, the viscosity of the coating will increase when the filler content exceeds 15%. Although the zinc powder can be modified by using a silane coupling agent to improve the interfacial bonding, it cannot match the long storage period requirement of the water-based system.

[0005] Therefore, how to obtain a water-based paint with ultra-thin thickness and long-term corrosion resistance and construction stability has a very good research prospect. SUMMARY

[0006] The present application aims to solve the problems in the prior art and provides an ultra-thin corrosion-resistant water-based paint and a preparation method thereof.

[0007] An ultra-thin corrosion-resistant water-based paint is composed of A component and B component with a mass ratio of 10:1-2. The raw materials of the A component include, by mass fraction: 40-60 parts of water-based epoxy emulsion, 30-50 parts of zinc powder, 1.2-3.6 parts of phosphoric acid, 1-3 parts of graphene oxide, 0.1-1 part of gamma-aminopropyl triethoxysilane, 1-2 parts of dispersant, 0.1-1 part of defoamer, 1-3 parts of corrosion inhibitor, and 0.1-1 part of leveling agent. The B component includes, by mass fraction: 40-60 parts of curing agent, 1-3 parts of accelerator, 1-3 parts of hyperbranched polyamide amine, 5-15 parts of cosolvent, and 20-30 parts of water.

[0008] Preferably, the solid content of the aqueous epoxy emulsion is 45-55%, and the epoxy value is 0.1-0.2 mol / 100g.

[0009] Preferably, the dispersant is a polyether-modified siloxane.

[0010] Preferably, the leveling agent is a fluorocarbon surfactant.

[0011] Preferably, the corrosion inhibitor includes ammonium molybdate.

[0012] Preferably, the accelerator is benzyl dimethyl amine.

[0013] Preferably, the co-solvent is dipropylene glycol butyl ether.

[0014] Preferably, the degree of hyperbranched polyamide amine is 2.0-4.0.

[0015] The preparation method of the above-mentioned ultra-thin corrosion-resistant water-based paint comprises the following steps:

[0016] S1, immerse zinc powder in aqueous phosphoric acid solution, ultrasonic treatment at 40-50℃ for 10-20min, centrifugal, washing to neutral, vacuum drying, crushing; add graphene oxide, γ-aminopropyl triethoxysilane, water, ball mill for 1-2h, to get composite zinc powder;

[0017] S2, preheat the aqueous epoxy emulsion to 40-50℃, adjust the pH value of the system to 8-9, add composite zinc powder, dispersant, continue to stir at 60-65℃ for 1-3h, reduce to room temperature, add defoaming agent, corrosion inhibitor, leveling agent, stir evenly, filter to get A component;

[0018] S3, mix the curing agent, hyperbranched polyamide amine, accelerator evenly, add co-solvent, ultrasonic treatment for 20-40min, to get B component.

[0019] Preferably, in S1, the ultrasonic frequency is 35-40kHz, and the ultrasonic power is 400-500W; the ball milling speed is 150-250r / min.

[0020] Preferably, in S3, the ultrasonic frequency is 30-40kHz, and the ultrasonic power is 400-500W.

[0021] The use method of the above-mentioned ultra-thin corrosion-resistant water-based paint comprises the following steps: mix A component and B component evenly, spray several times to the area to be coated, the film thickness of each time is 15-25μm, the total thickness of the obtained coating film is 60-75μm, and bake and cure at 70-80℃.

[0022] Beneficial effects:

[0023] The application adopts phosphoric acid treatment to make the zinc powder surface generate a porous zinc phosphate layer, and the silicon hydroxyl generated by hydrolysis of gamma-aminopropyl triethoxysilane is combined with the hydroxyl on the surface of the phosphating layer to form a Si-O-Zn covalent bond, and the terminal amino group is bonded with the carboxyl of graphene oxide, and a three-dimensional cross-linked network is constructed under the combined action, which significantly reduces the electrostatic attraction between zinc powder particles, enables the zinc powder to be uniformly dispersed in the aqueous system for a long time (storage period ≥ 6 months), and avoids coating defects caused by sedimentation during construction.

[0024] The application utilizes the graphene sheet layer in the composite zinc powder to form a dense physical barrier in the coating, so that the Cl- permeability is greatly reduced, and the protective performance is better than that of the traditional 200 μm coating when the film thickness is only 75 μm, and the chemical bonding of graphene and zinc powder can effectively inhibit the interfacial phase separation and significantly enhance the adhesion of the coating.

[0025] The terminal amino group of the hyperbranched polyamide amine reacts with the epoxy group to form a molecular level cross-linked structure, and the unreacted amino group is combined with the composite zinc powder and can form a coordination complex with Zn2+ released by the corrosion of the zinc powder, forming a self-repairing protective interface, which not only inhibits the further corrosion of zinc, but also keeps the adhesion strength of the coating stable.

[0026] The application not only has good environmental protection, but also can achieve long-acting corrosion resistance while ensuring ultra-thin thickness, and has good construction stability, and has significant application value in harsh environments such as ships and offshore wind power. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The impact resistance and adhesion of the coating film prepared from the ultra-thin corrosion-resistant water-based paint obtained in Example 5 and Comparative Example 1-2 are compared.

[0028] Figure 2 The self-repairing rate of the coating film prepared from the ultra-thin corrosion-resistant water-based paint obtained in Example 5 and Comparative Example 1-2 is compared. DETAILED DESCRIPTION

[0029] The application will be further described below in combination with specific examples.

[0030] The water-based epoxy emulsion is purchased from Guangzhou Gensheng New Material Co., Ltd., and the brand is GL 1900, the solid content is 50±2%, and the epoxy value is 0.17±0.01 mol / 100g.

[0031] Example 1

[0032] An ultra-thin corrosion-resistant water-based paint is composed of A component and B component in a mass ratio of 10:1.

[0033] The raw materials of the A component include: water-based epoxy emulsion 400 g, zinc powder 300 g, phosphoric acid 12 g, graphene oxide 10 g, γ-aminopropyl triethoxysilane 1 g, BYK-333 10 g, TEGO Foamex 825 1 g, ammonium molybdate 10 g, and EFKA-3777 71 g.

[0034] The B component includes: polyether amine 40 g, benzyl dimethyl amine 1 g, 2.0 generation hyperbranched polyamidoamine 1 g, dipropylene glycol butyl ether 5 g, and deionized water 20 g.

[0035] The preparation method of the above-mentioned ultra-thin corrosion-resistant water-based paint includes the following steps:

[0036] S1, immerse the zinc powder in a 1.5% mass fraction phosphoric acid solution, ultrasonic treatment at 40℃ for 10 min, ultrasonic frequency is 35 kHz, ultrasonic power is 400 W, centrifugal, wash with deionized water until neutral, vacuum drying at 105℃, crushing; add graphene oxide, γ-aminopropyl triethoxysilane, 200 g of deionized water, mix, and ball mill at a speed of 150 r / min for 1 h to obtain composite zinc powder;

[0037] S2, preheat the water-based epoxy emulsion to 40℃, adjust the pH value of the system to 8-9, add the composite zinc powder, BYK-333, heat to 60℃, continue to stir for 1 h at a stirring speed of 500 r / min, cool to room temperature, add TEGO Foamex 825, ammonium molybdate, and EFKA-3777, stir evenly, and filter to obtain the A component;

[0038] S3, mix the polyether amine, hyperbranched polyamidoamine, and benzyl dimethyl amine evenly, add dipropylene glycol butyl ether and deionized water, ultrasonic treatment for 20 min at an ultrasonic frequency of 30 kHz and an ultrasonic power of 400 W to obtain the B component.

[0039] Example 2

[0040] An ultra-thin corrosion-resistant water-based paint is composed of the A component and the B component in a mass ratio of 10:2.

[0041] The raw materials of the A component include: water-based epoxy emulsion 600 g, zinc powder 500 g, phosphoric acid 36 g, graphene oxide 30 g, γ-aminopropyl triethoxysilane 10 g, BYK-333 20 g, TEGO Foamex 825 10 g, ammonium molybdate 30 g, and EFKA-3777 710 g.

[0042] The B component includes: polyether amine 60 g, benzyl dimethyl amine 3 g, 4.0 generation hyperbranched polyamidoamine 3 g, dipropylene glycol butyl ether 15 g, and deionized water 30 g.

[0043] The preparation method of the super-thin corrosion-resistant water-based paint comprises the following steps:

[0044] S1, immerse the zinc powder in a 1200g 3% phosphoric acid solution, ultrasonic treatment at 50℃ for 20min, ultrasonic frequency is 40kHz, ultrasonic power is 500W, centrifugal, wash with deionized water until neutral, vacuum drying at 105℃, crushing; add graphene oxide, gamma-aminopropyl triethoxysilane, 300g deionized water, ball mill at a speed of 250r / min for 2h to obtain composite zinc powder;

[0045] S2, preheat the water-based epoxy emulsion to 50℃, adjust the pH value of the system to 8-9, add the composite zinc powder, BYK-333, heat to 65℃ and continue stirring for 3h at a stirring speed of 1000r / min, cool to room temperature, add TEGO Foamex 825, ammonium molybdate, and EFKA-3777, stir uniformly, and filter to obtain component A;

[0046] S3, mix polyether amine, hyperbranched polyamide amine, and benzyl dimethyl amine uniformly, ultrasonic treatment for 40min at an ultrasonic frequency of 40kHz and an ultrasonic power of 500W with dipropylene glycol butyl ether and deionized water to obtain component B.

[0047] Example 3

[0048] A super-thin corrosion-resistant water-based paint is composed of component A and component B in a mass ratio of 10:1.3.

[0049] The raw materials of component A include: water-based epoxy emulsion 550g, zinc powder 350g, phosphoric acid 22g, graphene oxide 25g, gamma-aminopropyl triethoxysilane 3g, BYK-333 18g, TEGO Foamex 825 3g, ammonium molybdate 25g, and EFKA-3777 2g.

[0050] Component B includes: polyether amine 55g, benzyl dimethyl amine 1.5g, 3.5-generation hyperbranched polyamide amine 1.5g, dipropylene glycol butyl ether 12g, and deionized water 22g.

[0051] The preparation method of the super-thin corrosion-resistant water-based paint comprises the following steps:

[0052] S1, immerse the zinc powder in a 1200g 3% phosphoric acid solution, ultrasonic treatment at 50℃ for 20min, ultrasonic frequency is 40kHz, ultrasonic power is 500W, centrifugal, wash with deionized water until neutral, vacuum drying at 105℃, crushing; add graphene oxide, gamma-aminopropyl triethoxysilane, 300g deionized water, ball mill at a speed of 250r / min for 2h to obtain composite zinc powder;

[0053] S2, preheat the aqueous epoxy emulsion to 42℃, adjust the pH value of the system to 8-9, add composite zinc powder, BYK-333, heat to 63℃ and continue stirring for 1.5h at a stirring speed of 900r / min, then reduce to room temperature, add TEGO Foamex 825, ammonium molybdate, and EFKA-3777 and stir uniformly to obtain component A;

[0054] S3, mix polyether amine, hyperbranched polyamide amine, and benzyldimethylamine uniformly, ultrasonically treat for 25min with dipropylene glycol butyl ether and deionized water at an ultrasonic frequency of 39kHz and an ultrasonic power of 420W to obtain component B.

[0055] Example 4

[0056] An ultrathin corrosion-resistant water-based paint is composed of component A and component B in a mass ratio of 10:1.7.

[0057] The raw materials of component A include: 450g of aqueous epoxy emulsion, 450g of zinc powder, 22.5g of phosphoric acid, 15g of graphene oxide, 7g of γ-aminopropyl triethoxysilane, 12g of BYK-333, 7g of TEGO Foamex 825, 15g of ammonium molybdate, and 8g of EFKA-3777.

[0058] Component B includes: 45g of polyether amine, 2.5g of benzyldimethylamine, 2.5g of 2.5-generation hyperbranched polyamide amine, 8g of dipropylene glycol butyl ether, and 28g of deionized water.

[0059] The preparation method of the above-mentioned ultrathin corrosion-resistant water-based paint comprises the following steps:

[0060] S1, immerse the zinc powder in a 900g phosphoric acid solution with a mass fraction of 2.5%, ultrasonically treat for 18min at a temperature of 42℃, an ultrasonic frequency of 36kHz, and an ultrasonic power of 470W, centrifuge, wash with deionized water until neutral, vacuum dry at a temperature of 105℃, and crush; mix with 220g of deionized water, and ball mill at a speed of 220r / min for 80min to obtain composite zinc powder;

[0061] S2, preheat the aqueous epoxy emulsion to 48℃, adjust the pH value of the system to 8-9, add composite zinc powder, BYK-333, heat to 61℃ and continue stirring for 2.5h at a stirring speed of 700r / min, then reduce to room temperature, add TEGO Foamex 825, ammonium molybdate, and EFKA-3777 and stir uniformly to obtain component A;

[0062] S3, the polyether amine, hyperbranched polyamide amine, benzyl dimethyl amine is mixed uniformly, and the dipropylene glycol butyl ether, deionized water is ultrasonically treated for 35 min, the ultrasonic frequency is 33 kHz, and the ultrasonic power is 480 W to obtain the B component.

[0063] Example 5

[0064] An ultrathin corrosion-resistant water-based paint is composed of A component and B component in a mass ratio of 10:1.5.

[0065] The raw materials of the A component include: water-based epoxy emulsion 500 g, zinc powder 400 g, phosphoric acid 22 g, graphene oxide 20 g, γ-aminopropyl triethoxysilane 5 g, BYK-333 15 g, TEGO Foamex 825 5 g, ammonium molybdate 20 g, and EFKA-3777 75 g.

[0066] The B component includes: polyether amine 50 g, benzyl dimethyl amine 2 g, 3.0 generation hyperbranched polyamide amine 2 g, dipropylene glycol butyl ether 10 g, and deionized water 25 g.

[0067] The preparation method of the above-mentioned ultrathin corrosion-resistant water-based paint comprises the following steps:

[0068] S1, the zinc powder is immersed in a 1000 g mass fraction of 2.2% phosphoric acid solution, ultrasonically treated at a temperature of 45℃ for 15 min, the ultrasonic frequency is 37.5 kHz, the ultrasonic power is 450 W, centrifuged, washed with deionized water until neutral, vacuum dried at a temperature of 105℃, and pulverized; the graphene oxide, γ-aminopropyl triethoxysilane, and 250 g of deionized water are mixed, and ball milled at a speed of 200 r / min for 90 min to obtain a composite zinc powder;

[0069] S2, the water-based epoxy emulsion is preheated to 45℃, the pH value of the system is adjusted to 8-9, the composite zinc powder, BYK-333, is added, the temperature is raised to 62℃, and the stirring is continued for 2 h at a stirring speed of 800 r / min, then the temperature is lowered to room temperature, TEGO Foamex 825, ammonium molybdate, and EFKA-3777 are added and uniformly stirred, and filtered to obtain the A component;

[0070] S3, the polyether amine, hyperbranched polyamide amine, benzyl dimethyl amine is mixed uniformly, and the dipropylene glycol butyl ether, deionized water is ultrasonically treated for 35 min, the ultrasonic frequency is 33 kHz, and the ultrasonic power is 480 W to obtain the B component.

[0071] Comparative Example 1

[0072] An ultrathin corrosion-resistant water-based paint is composed of A component and B component in a mass ratio of 10:1.5.

[0073] The raw materials of component A include: 500g water-based epoxy emulsion, 400g zinc powder, 22g phosphoric acid, 25g graphene oxide, 15g BYK-333, 5g TEGO Foamex 825, 20g ammonium molybdate, and 5g EFKA-3777.

[0074] Component B includes: 50g of polyetheramine, 2g of benzyldimethylamine, 2g of 3.0 generation hyperbranched polyamidoamine, 10g of dipropylene glycol butyl ether, and 25g of deionized water.

[0075] The preparation method of the above-mentioned ultra-thin corrosion-resistant water-based coating comprises the following steps:

[0076] S1. Immerse zinc powder in 1000 g of a 2.2% phosphoric acid solution, ultrasonically treat at 45° C. for 15 min, with an ultrasonic frequency of 37.5 kHz and an ultrasonic power of 450 W, centrifuge, wash with deionized water until neutral, vacuum dry at 105° C., and crush; add graphene oxide and 250 g of deionized water, mix, and ball mill at 200 rpm for 90 min to obtain composite zinc powder;

[0077] S2. Preheat the aqueous epoxy emulsion to 45° C., adjust the pH value of the system to 8-9, add composite zinc powder and BYK-333, raise the temperature to 62° C., continue stirring for 2 h at a stirring speed of 800 r / min, cool to room temperature, add TEGO Foamex 825, ammonium molybdate, and EFKA-3777, stir evenly, and filter to obtain component A;

[0078] S3. Evenly mix polyetheramine, hyperbranched polyamide amine, and benzyldimethylamine, add dipropylene glycol butyl ether and deionized water, and ultrasonically treat for 30 minutes at an ultrasonic frequency of 36 kHz and an ultrasonic power of 450 W to obtain component B.

[0079] Comparative Example 2

[0080] An ultra-thin corrosion-resistant water-based coating consists of component A and component B in a mass ratio of 10:1.5.

[0081] The raw materials of component A include: 500g water-based epoxy emulsion, 400g zinc powder, 22g phosphoric acid, 20g graphene oxide, 5g γ-aminopropyltriethoxysilane, 15g BYK-333, 5g TEGO Foamex 825, 20g ammonium molybdate, and 5g EFKA-3777.

[0082] Component B includes: 50g of polyetheramine, 4g of benzyldimethylamine, 10g of dipropylene glycol butyl ether, and 25g of deionized water.

[0083] The preparation method of the above-mentioned ultra-thin corrosion-resistant water-based coating comprises the following steps:

[0084] S1, immerse zinc powder into 1000g of a phosphoric acid solution with a mass fraction of 2.2%, ultrasonic treatment for 15min at a temperature of 45℃, ultrasonic frequency of 37.5kHz and ultrasonic power of 450W, centrifugal, washed with deionized water until neutral, vacuum drying at a temperature of 105℃, crushing; add graphene oxide, γ-aminopropyl triethoxysilane, 250g of deionized water, ball milling at a speed of 200r / min for 90min to obtain composite zinc powder;

[0085] S2, preheat the aqueous epoxy emulsion to 45℃, adjust the pH value of the system to 8-9, add the composite zinc powder, BYK-333, and continue to stir at a temperature of 62℃ for 2h at a stirring speed of 800r / min, then cool to room temperature, add TEGO Foamex 825, ammonium molybdate, and EFKA-3777, stir uniformly, and filter to obtain component A;

[0086] S3, mix polyetheramine and benzyl dimethylamine uniformly, ultrasonic treatment for 30min at an ultrasonic frequency of 36kHz and an ultrasonic power of 450W with dipropylene glycol butyl ether and deionized water to obtain component B.

[0087] The A components of the ultra-thin corrosion-resistant water-based paint obtained in Example 5 and Comparative Examples 1-2 were stored at room temperature for 6 months, and it was found that the A components of Example 5 and Comparative Example 2 did not delaminate or precipitate after 6 months of storage at room temperature; while the A component of Comparative Example 1 delaminated and precipitated after only 2 months of storage at room temperature.

[0088] The ultra-thin corrosion-resistant water-based paint obtained in Example 5 and Comparative Examples 1-2 was sprayed, as follows: using a steel plate (Q195) as the substrate (cleaned and polished), the A component and the B component were mixed uniformly, and sprayed 3 times on the area to be coated, with a film thickness of 25μm each time, and the total film thickness of the obtained coating film was 75μm, and the coating film was baked and cured at 75℃ for 20min.

[0089] The impact resistance of the coating films of each group was determined according to GB / T 1732-2020 "Paint Film Impact Resistance Test Method", and the maximum height without cracks was used to represent the impact resistance. The adhesion of the coating films of each group was determined according to GB / T 5210-2006 "Color Paint and Varnish Pull-off Test".

[0090] As shown in Figure 1 , the coating film prepared from the ultra-thin corrosion-resistant water-based paint obtained in Example 5 had the best impact resistance and adhesion, which was better than that of Comparative Examples 1-2 (P<0.05).

[0091] The water resistance, acid resistance (10% hydrochloric acid), and alkali resistance (30% sodium hydroxide solution) of each coating group were tested according to GB / T 1733-1993, "Determination of Water Resistance of Paint Films." The salt spray resistance of each coating group was tested according to GB / T 10125-2012, "Artificial Atmosphere Corrosion Test Salt Spray Test." The results are shown in Table 1.

[0092] Table 1 Results of ultra-thin corrosion-resistant water-based coating films obtained in Example 5 and Comparative Examples 1-2

[0093]

[0094] It can be seen from Table 1 that the coating film prepared using the ultra-thin corrosion-resistant water-based coating obtained in Example 5 has excellent water resistance and corrosion resistance.

[0095] With reference to ASTM D7027-05 "Test Method for Scratch Recovery of Plastics," each group of coatings was scratched using a multi-finger scratch tester. The scratch tip was made of stainless steel and had a diameter of 1 mm. The test load was 15 N, the scratch speed was 100 mm / s, and the scratch length was 100 mm. A laser confocal microscope was used to observe the surface scratch width. The samples were then allowed to stand in an environment of 25°C and 80% RH for 24 hours. The surface scratch width was then observed again, and the self-repair rate was calculated.

[0096] Self-repair rate = width of surface scratch after standing at room temperature for 24 hours ÷ width of original surface scratch × 100%

[0097] like Figure 2 As shown, the self-repair rate of the coating film prepared using the ultra-thin corrosion-resistant water-based coating of Example 5 is the highest and is higher than 90%, which is better than that of Comparative Examples 1-2 (P < 0.05), indicating that the ultra-thin corrosion-resistant water-based coating obtained by the present invention has good self-repairing properties.

[0098] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. An ultra-thin corrosion-resistant water-based coating, characterized in that: It is composed of component A and component B in a mass ratio of 10:1-2; The raw materials of component A include, by mass: 40-60 parts of water-based epoxy emulsion, 30-50 parts of zinc powder, 1.2-3.6 parts of phosphoric acid, 1-3 parts of graphene oxide, 0.1-1 part of γ-aminopropyltriethoxysilane, 1-2 parts of dispersant, 0.1-1 part of defoamer, 1-3 parts of corrosion inhibitor, and 0.1-1 part of leveling agent; Component B includes, by mass: 40-60 parts of curing agent, 1-3 parts of accelerator, 1-3 parts of hyperbranched polyamidoamine, 5-15 parts of cosolvent, and 20-30 parts of water; The preparation method of the ultra-thin corrosion-resistant water-based coating comprises the following steps: S1. Immerse zinc powder in a phosphoric acid aqueous solution, ultrasonically treat at 40-50°C for 10-20 minutes, centrifuge, wash until neutral, vacuum dry, and crush; add graphene oxide, γ-aminopropyltriethoxysilane, and water, mix, and ball mill for 1-2 hours to obtain composite zinc powder; S2. Preheat the waterborne epoxy emulsion to 40-50°C, adjust the pH value of the system to 8-9, add composite zinc powder and dispersant, raise the temperature to 60-65°C and continue stirring for 1-3 hours, cool to room temperature, add defoamer, corrosion inhibitor, and leveling agent, stir evenly, and filter to obtain component A; S3. Evenly mix the curing agent, hyperbranched polyamidoamine and accelerator, add a cosolvent and water, and ultrasonically treat for 20-40 minutes to obtain component B.

2. The ultra-thin corrosion-resistant water-based coating according to claim 1, characterized in that: The solid content of water-based epoxy emulsion is 45-55%, and the epoxy value is 0.1-0.2 mol / 100g.

3. The ultra-thin corrosion-resistant water-based coating according to claim 1, characterized in that: The dispersant is polyether modified siloxane; the leveling agent is fluorocarbon surfactant.

4. The ultra-thin corrosion-resistant water-based coating according to claim 1, characterized in that: Corrosion inhibitors include: Ammonium molybdate.

5. The ultra-thin corrosion-resistant water-based coating according to claim 1, characterized in that: The accelerator is benzyldimethylamine; the cosolvent is dipropylene glycol butyl ether.

6. The ultra-thin corrosion-resistant water-based coating according to claim 1, characterized in that: The generation number of the hyperbranched polyamidoamine is 2.0-4.

0.

7. A method for preparing the ultra-thin corrosion-resistant water-based coating according to any one of claims 1 to 6, characterized in that: The steps include: S1. Immerse zinc powder in a phosphoric acid aqueous solution, ultrasonically treat at 40-50°C for 10-20 minutes, centrifuge, wash until neutral, vacuum dry, and crush; add graphene oxide, γ-aminopropyltriethoxysilane, and water, mix, and ball mill for 1-2 hours to obtain composite zinc powder; S2. Preheat the waterborne epoxy emulsion to 40-50°C, adjust the pH value of the system to 8-9, add composite zinc powder and dispersant, raise the temperature to 60-65°C and continue stirring for 1-3 hours, cool to room temperature, add defoamer, corrosion inhibitor, and leveling agent, stir evenly, and filter to obtain component A; S3. Evenly mix the curing agent, hyperbranched polyamidoamine and accelerator, add a cosolvent and water, and ultrasonically treat for 20-40 minutes to obtain component B.

8. The method for preparing the ultra-thin corrosion-resistant water-based coating according to claim 7, characterized in that: In S1, the ultrasonic frequency is 35-40 kHz, the ultrasonic power is 400-500 W, and the ball milling speed is 150-250 r / min.

9. The method for preparing the ultra-thin corrosion-resistant water-based coating according to claim 7, characterized in that: In S3, the ultrasonic frequency is 30-40kHz and the ultrasonic power is 400-500W.

10. A method for using the ultra-thin corrosion-resistant water-based coating according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: uniformly mixing component A and component B, spraying the components to be coated several times, forming a film with a thickness of 15-25 μm each time, and obtaining a total coating thickness of 60-75 μm, and baking and curing at 70-80°C.

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