Two-component waterborne epoxy coating and anti-corrosion coating

Abstract

The invention relates to a two-component waterborne epoxy coating and an anti-corrosion coating. The bi-component waterborne epoxy coating comprises a component A and a component B. The component A comprises, by mass, 6-10 parts of a waterborne epoxy curing agent, 0.5-2 parts of polyurea nanofibers and 0.5-2 parts of modified carbon quantum dots; wherein the modified carbon quantum dots comprise the modified carbon quantum dots in which a C source and an N source are provided by hexamethylenetetramine and an N source and an S source are provided by thiourea; the polyurea nanofiber contains amido. Through cooperation of the components, a waterborne epoxy coating prepared from the two-component waterborne epoxy coating shows excellent water vapor barrier capacity, has the capacity of forming coordinate bonds with corrosion products and self-repairing, and can keep long-term effective corrosion resistance in a heavy corrosion environment.

Description

Technical Field

[0001] The present application relates to the technical field of functional coatings, and in particular to a two-component waterborne epoxy coating and an anti-corrosion coating. Background Art

[0002] Two-component waterborne epoxy coating systems are green coating systems that use water as the primary dispersion medium, effectively reducing environmental pollution during coating application. These two-component waterborne epoxy anti-corrosion coatings contain a waterborne epoxy resin and a waterborne epoxy curing agent. The resulting epoxy coating exhibits excellent adhesion and corrosion resistance, effectively combating corrosion in power equipment in harsh environments and is now widely used in the corrosion protection field.

[0003] However, due to their strong hydrophilicity, waterborne epoxy coatings have unstable water vapor barrier capabilities. In heavily corrosive areas, such as industrial atmospheric corrosion zones and coastal marine atmospheres, the combined effects of acid rain and corrosive chloride ions can cause traditional waterborne epoxy coatings to quickly flake off or even suffer corrosion perforation. Currently, the corrosion resistance of traditional waterborne epoxy coatings still needs to be optimized. Summary of the Invention

[0004] Based on this, it is necessary to provide a two-component waterborne epoxy coating that can stabilize the corrosion resistance of the obtained epoxy coating for a long time, and an anti-corrosion coating prepared therefrom.

[0005] In a first aspect of the present application, a two-component waterborne epoxy coating is provided.

[0006] A two-component waterborne epoxy coating, comprising component A and component B, wherein component B comprises a waterborne epoxy resin;

[0007] In parts by mass, the A component includes the following components:

[0008] 6 to 10 parts of water-based epoxy curing agent;

[0009] 0.5 to 2 parts of polyurea nanofiber; and

[0010] 0.5 to 2 parts of modified carbon quantum dots;

[0011] Wherein, the modified carbon quantum dots include modified carbon quantum dots in which hexamethylenetetramine provides the C source and the N source, and thiourea provides the N source and the S source;

[0012] The polyurea nanofibers contain amine groups.

[0013] In some embodiments, the polyurea nanofibers have a length of 5 μm to 20 μm; and / or

[0014] The cross-sectional diameter of the polyurea nanofiber is 10 nm to 60 nm; and / or

[0015] The D50 of the carbon quantum dots is 4 nm to 7 nm.

[0016] In some embodiments, the method for preparing the polyurea nanofibers includes:

[0017] Preparation of polyureas by reaction of aliphatic diisocyanates with aliphatic diamines;

[0018] The polyurea was electrospun and dried.

[0019] In some embodiments, the aliphatic diisocyanate comprises hexamethylene diisocyanate; and / or

[0020] The aliphatic diamine includes ethylenediamine.

[0021] In some embodiments, the method for preparing the modified carbon quantum dots comprises:

[0022] dissolving thiourea and hexamethylenetetramine in a polar solvent to obtain a first solution;

[0023] heat-treating the first solution to obtain a second solution;

[0024] dialyzing the second solution to obtain a retentate solution;

[0025] The retentate solution is dried.

[0026] In some embodiments, the dialysis molecular weight cut-off is 450Da to 550Da; and / or

[0027] The heat treatment temperature is 160°C to 220°C; and / or

[0028] The heat treatment time is 4 hours to 24 hours.

[0029] In some embodiments, the component A further comprises the following components in parts by mass:

[0030] 30~50 parts of pigments and fillers

[0031] 10 to 15 parts of anti-rust pigment; and

[0032] 1 to 3 parts of silane coupling agent.

[0033] In some embodiments, the anti-rust pigment includes one or more of orthophosphate, modified orthophosphate, polyphosphate, and modified polyphosphate.

[0034] In some embodiments, the color filler includes a coloring pigment and a bulk filler;

[0035] The coloring pigment includes one or more of iron oxide yellow, iron oxide red, rutile titanium dioxide and carbon black;

[0036] The physical filler includes one or more of precipitated barium sulfate, mica powder, talc powder, silica powder, heavy calcium carbonate, fumed silica and bentonite.

[0037] In a second aspect of the present application, an anti-corrosion coating is provided. The anti-corrosion coating is prepared using the above-mentioned two-component water-based epoxy coating.

[0038] The A component of the above two-component waterborne epoxy coating uses modified carbon quantum dots containing amino groups, which can not only give the epoxy coating a certain self-healing ability through the hydrogen bond cross-linking network, but also can 3+ Ionic coordination forms a stable complex, thereby preventing further corrosion spread, and due to the presence of S element, its coordination ability with metal ions is further enhanced. In addition, component A also contains polyurea nanofibers containing amino groups, which can provide a high-strength urea bond network for the epoxy coating, effectively improving the water vapor barrier and wear resistance of the epoxy coating. Through the combination of the above components, the epoxy coating prepared using this two-component water-based epoxy coating can exhibit excellent water vapor barrier capabilities, and has the ability to form coordination bonds with corrosion products and self-repair, thereby maintaining long-term and effective corrosion resistance in heavy corrosion environments. DETAILED DESCRIPTION

[0039] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar modifications without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0040] In the description of this application, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined. In this application, "at least one" means more than one, such as one, two, or more than two. "Multiple" or "several" means at least two, such as two, three, etc.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0042] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe a feature or characteristic, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein are understood to include any and all subranges subsumed therein.

[0043] Unless otherwise specified, the percentage contents involved in this application refer to mass percentage for solid-liquid mixture and solid-solid phase mixture, and refer to volume percentage for liquid-liquid phase mixture.

[0044] Unless otherwise specified, all steps of the present application may be performed sequentially or randomly. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0045] In this application, “above” or “below” includes the number itself. For example, “1 below” includes 1.

[0046] Unless otherwise specified, the temperature parameters in this application allow for both constant temperature treatment and temperature fluctuations within a certain temperature range. It should be understood that the constant temperature treatment allows for temperature fluctuations within the accuracy range of instrument control. Fluctuations within ranges such as ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are permitted.

[0047] As an integral component of power transmission systems, the safe operation of power equipment is crucial. However, due to long-term exposure to corrosive environments such as moisture and salt spray, power equipment is prone to corrosion, which affects the stability and safety of the power system.

[0048] Two-component waterborne epoxy coating systems are green coating systems that use water as the primary dispersion medium. They can effectively reduce the use of organic solvents, thereby reducing environmental pollution caused by coating construction. However, due to the high hydrophilicity of waterborne epoxy coatings, their barrier ability to water vapor is unstable. In heavily corrosive areas such as industrial atmospheric corrosion zones and coastal marine atmospheres, the coupling effect of acid rain and corrosive chloride ions can cause traditional waterborne epoxy coatings to fall off quickly and even cause corrosion perforation. Currently, the anti-corrosion performance of traditional waterborne epoxy anti-corrosion coatings still needs to be optimized.

[0049] Based on this, the first aspect of the present application provides a two-component water-based epoxy coating that can ensure long-term stability in the corrosion resistance of the resulting epoxy coating.

[0050] Exemplarily, a two-component waterborne epoxy coating comprises component A and component B, wherein component B comprises a waterborne epoxy resin;

[0051] Component A includes the following components in parts by mass:

[0052] 6 to 10 parts of water-based epoxy curing agent;

[0053] 0.5 to 2 parts of polyurea nanofiber; and

[0054] 0.5 to 2 parts of modified carbon quantum dots;

[0055] Among them, the modified carbon quantum dots include modified carbon quantum dots in which hexamethylenetetramine provides the C source and the N source, and thiourea provides the N source and the S source;

[0056] Polyurea nanofibers contain amine groups.

[0057] The modified carbon quantum dots used in component A of the two-component waterborne epoxy coating of the present application include modified carbon quantum dots in which hexamethylenetetramine provides the C and N sources and thiourea provides the N and S sources, thereby making the modified carbon quantum dots contain amino groups and S elements, which can not only give the epoxy coating a certain self-healing ability through the hydrogen bond cross-linking network, but also can make the epoxy coating have a certain self-healing ability through the amino group and Fe 3+ The ions coordinate to form a stable complex, thereby preventing the further spread of corrosion; in addition, due to the presence of S elements, the coordination ability of the modified carbon quantum dots with metal ions is enhanced, and the CS bond can also serve as an adsorption layer to block the contact between the corrosive medium and the metal, further improving the corrosion resistance of the epoxy coating.

[0058] In addition, component A also has polyurea nanofibers containing amino groups, which can provide a high-strength urea bond network for the epoxy coating and can participate in the curing reaction to a certain extent, further improving the density and compatibility of the cross-linked network, thereby effectively improving the barrier properties and wear resistance of the epoxy coating.

[0059] By combining the above components, the epoxy coating prepared using the two-component water-based epoxy coating can have excellent water vapor barrier capabilities, and has the ability to form coordination bonds with corrosion products and self-repair, and can maintain good corrosion resistance for a long time in a heavy corrosion environment.

[0060] Optionally, in component A of the two-component waterborne epoxy coating, the mass fraction of the waterborne epoxy curing agent can be but is not limited to 6 parts, 7 parts, 8 parts, 9 parts, 10 parts or other values ​​within the range of 6 parts to 10 parts.

[0061] Optionally, in component A of the two-component waterborne epoxy coating, the mass fraction of the polyurea nanofibers may be, but is not limited to, 0.5 parts, 1 part, 1.5 parts, 2 parts, or other values ​​within the range of 0.5 parts to 2 parts.

[0062] Optionally, in component A of the two-component waterborne epoxy coating, the mass fraction of the modified carbon quantum dots may be, but is not limited to, 0.5 parts, 1 part, 1.5 parts, 2 parts, or other values ​​within the range of 0.5 parts to 2 parts.

[0063] In some embodiments, the polyurea nanofibers have a length of 5 μm to 20 μm. Maintaining the polyurea nanofibers within this range can provide the epoxy coating with improved barrier properties. The polyurea nanofibers should not be too long, as this may affect the compatibility of the epoxy coating. Alternatively, the polyurea nanofibers may have a length of, but are not limited to, 5 μm, 10 μm, 15 μm, 20 μm, or other values ​​within the range of 5 μm to 20 μm.

[0064] In some embodiments, the cross-sectional diameter of the polyurea nanofiber is 10 nm to 60 nm. Alternatively, the cross-sectional diameter of the polyurea nanofiber can be, but is not limited to, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, or other values ​​within the range of 10 nm to 60 nm.

[0065] In some embodiments, the D50 of the carbon quantum dots is 4 nm to 7 nm. Alternatively, the diameter of the carbon quantum dots may be, but is not limited to, 4 nm, 4.5 nm, 5 nm, 5.5 nm, 6 nm, 6.5 nm, 7 nm, or other values ​​within the range of 4 nm to 7 nm.

[0066] In some embodiments, the method for preparing polyurea nanofibers includes:

[0067] Preparation of polyureas by reaction of aliphatic diisocyanates with aliphatic diamines;

[0068] The polyurea was electrospun and dried.

[0069] In some embodiments, a third solution containing 10 wt % to 15 wt % of an aliphatic diisocyanate is mixed with a fourth solution containing 4 wt % to 6 wt % of an aliphatic diamine, and the mixture is reacted at 40° C. to 60° C. for 4 h to 10 h to obtain a polyurea solution containing polyurea;

[0070] The polyurea solution is electrospun at a voltage of 15kV to 25kV, and then washed and dried to obtain polyurea nanofibers.

[0071] In some embodiments, the drying method includes vacuum drying, and the drying time is 2 hours to 16 hours.

[0072] In some embodiments, the aliphatic diisocyanate includes hexamethylene diisocyanate.

[0073] In some embodiments, the aliphatic diamine includes ethylenediamine.

[0074] In some embodiments, the method for preparing modified carbon quantum dots comprises:

[0075] dissolving thiourea and hexamethylenetetramine in a polar solvent to obtain a first solution;

[0076] heat-treating the first solution to obtain a second solution;

[0077] dialyzing the second solution to obtain a retentate solution;

[0078] The retentate solution was dried.

[0079] In some embodiments, the polar solvent includes ethanol.

[0080] In some embodiments, the drying method comprises freeze-drying.

[0081] In some embodiments, the molecular weight cut-off for dialysis is 450 Da to 550 Da.

[0082] In some embodiments, the dialysis process comprises:

[0083] A 450-550 Da dialysis bag is used to assist dialysis, and the dialysis is continued for 12-24 hours, with the filtrate replaced every 2-4 hours. Optionally, the filtrate includes deionized water.

[0084] In some embodiments, the heat treatment temperature is 160°C to 220°C.

[0085] In some embodiments, the heat treatment time is 4 hours to 24 hours.

[0086] In some embodiments, component A further comprises the following components, in parts by mass:

[0087] 30~50 parts of pigments and fillers;

[0088] 10 to 15 parts of anti-rust pigment; and

[0089] 1 to 3 parts of silane coupling agent.

[0090] The addition of pigments and anti-rust pigments can further improve the corrosion resistance and wear resistance of the resulting epoxy coating, but this can reduce the compatibility between the epoxy coating components. To address this issue, the present application adds a silane coupling agent to assist in dispersing the pigments and fillers, allowing the components to form a network structure with the help of the silane coupling agent, thereby effectively improving the compatibility between the components and fully realizing the corrosion resistance.

[0091] Optionally, in component A of the two-component waterborne epoxy coating, the mass fraction of pigments and fillers may be, but is not limited to, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, or other values ​​within the range of 30 to 50 parts.

[0092] Optionally, in component A of the two-component waterborne epoxy coating, the mass fraction of the rust-proof pigment may be, but is not limited to, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts or other values ​​within the range of 10 to 15 parts.

[0093] Optionally, in component A of the two-component waterborne epoxy coating, the mass fraction of the silane coupling agent may be, but is not limited to, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, or other values ​​within the range of 1 part to 3 parts.

[0094] In some embodiments, the silane coupling agent includes one or more of perfluorodecyltrimethoxysilane, perfluorodecyltriethoxysilane, perfluorooctylmethyldimethoxysilane, and perfluorooctyltriethoxysilane.

[0095] In some embodiments, the anti-rust pigment includes one or more of orthophosphate, modified orthophosphate, polyphosphate, and modified polyphosphate.

[0096] In some embodiments, the pigments and fillers include coloring pigments and bulk fillers.

[0097] In some embodiments, the coloring pigment includes one or more of yellow iron oxide, red iron oxide, rutile titanium dioxide, and carbon black.

[0098] In some embodiments, the bulk filler includes one or more of precipitated barium sulfate, mica powder, talc, silica powder, ground calcium carbonate, fumed silica, and bentonite.

[0099] In some embodiments, component A further comprises the following components, in parts by mass:

[0100] 10-30 parts water;

[0101] 3 to 8 parts of additives; and

[0102] 1 to 3 parts of auxiliary solvent;

[0103] In some embodiments, the adjuvant includes one or more of a film-forming aid, an anti-flash rust agent, a defoaming agent, a leveling agent, a wetting agent, a dispersant, a thickener, an anti-settling agent, and an anti-mildew agent.

[0104] In some embodiments, the auxiliary solvent includes propylene glycol monomethyl ether. Propylene glycol monomethyl ether has the functions of adjusting viscosity, adjusting paint film drying time, adjusting surface tension, and assisting film formation in water-based coatings.

[0105] In some embodiments, the solid content of the first epoxy resin emulsion is 30% to 70%.

[0106] In some embodiments, the solid content of the second epoxy resin emulsion is 30% to 70%.

[0107] In some embodiments, the waterborne epoxy curing agent includes one or more of a modified polyamine adduct and a polyamide adduct.

[0108] In some embodiments, the waterborne epoxy resin includes a bisphenol A epoxy resin.

[0109] In some embodiments, the waterborne epoxy resin comprises, by weight percentage of the waterborne epoxy resin:

[0110] 15% to 25% of the first epoxy resin emulsion; and

[0111] The second epoxy resin emulsion is 75%~85%;

[0112] The first epoxy resin emulsion contains a first epoxy resin with an epoxy equivalent weight of 350 g / eq to 450 g / eq, while the second epoxy resin emulsion contains a second epoxy resin with an epoxy equivalent weight of 845 g / eq to 1000 g / eq. The mixing ratio of the first and second epoxy resin emulsions with different epoxy equivalent weights helps balance the crosslinking degree and flexibility of the resulting epoxy coating, resulting in an epoxy coating with excellent overall performance and enhanced corrosion resistance.

[0113] In a second aspect of the present application, an anti-corrosion coating is provided which is prepared using the above-mentioned two-component water-based epoxy coating.

[0114] In some embodiments, the method for preparing the anti-corrosion coating comprises:

[0115] Component A and component B are mixed in a mass ratio of 100:(30~45), mixed and dispersed at 25℃~35℃ for 0.5h~2h, and cured at 100℃~120℃ for 0.5h~2h to form an anti-corrosion coating.

[0116] In a third aspect of the present application, a method for preparing component A in the above-mentioned two-component waterborne epoxy coating is provided.

[0117] The preparation method of component A comprises the following steps:

[0118] Mix the components of component A to obtain.

[0119] In some embodiments, the pigment filler, the anti-rust pigment and the modified carbon quantum dots are mixed and ground to a slurry fineness of ≤30 μm to obtain a water-based color paste;

[0120] The water-based color paste is mixed with a water-based epoxy curing agent, polyurea nanofibers, a silane coupling agent, water, an auxiliary agent and an auxiliary solvent to obtain component A.

[0121] The present application is further described in detail below with reference to specific embodiments.

[0122] In the following specific examples and comparative examples, the raw materials used, unless otherwise specified, are all commercially available products; the instruments used, unless otherwise specified, are all commercially available products; and the processes used, unless otherwise specified, are all routinely selected by those skilled in the art.

[0123] In the following specific examples and comparative examples, the water-based epoxy curing agent was produced by Guangzhou Epoxy Material Technology Co., Ltd. and is available as K-17 water-based epoxy curing agent. The first epoxy resin emulsion was produced by Dongguan Rongzhong Chemical Co., Ltd. and is available as A102 epoxy resin emulsion. The second epoxy resin emulsion was produced by Nan Ya Plastics Industry Co., Ltd. and is available as NPES-904H epoxy resin emulsion. BYK194N dispersant and BYK024 defoamer were produced by BYK Chemie AG in Germany. R706 titanium dioxide was produced by DuPont in the United States. AQ-600 anti-settling agent was produced by Desbaron Co., Ltd. in Japan. TEGO4100 wetting agent was produced by Digo AG in Germany. The polyamide wax PA-800 thickener was produced by Zhejiang Fenghong New Materials Co., Ltd., and BYK346 wetting agent was produced by BYK Chemie AG in Germany.

[0124] Example 1

[0125] This embodiment provides a two-component water-based epoxy coating.

[0126] The two-component waterborne epoxy coating of this embodiment is divided into component A and component B, wherein the composition of component A is shown in Table 1, and the composition of component B is shown in Table 2.

[0127] Table 1 Composition of component A of Example 1

[0128]

[0129] Table 2 Composition of component B of Example 1

[0130]

[0131] The polyurea nanofiber preparation method is as follows:

[0132] 15 wt% hexamethylene diisocyanate was dissolved in octane and reacted with 6 wt% ethylenediamine solution to generate a polyurea solution, which was then electrospun at 20 kV. The fibers were washed with deionized water and then vacuum dried at room temperature for 12 h to obtain polyurea nanofibers.

[0133] The preparation method of modified carbon quantum dots is as follows:

[0134] Adding ethanol as a solvent into a reaction container, followed by adding thiourea and hexamethylenetetramine, and uniformly dispersing them by ultrasonication to obtain a first solution;

[0135] The first solution was placed into the inner lining of the reactor, placed in an oven at 200°C and heated for 18 hours, and then the impurities were filtered out to obtain the second solution;

[0136] The filtrate was dialyzed using a 500Da dialysis bag for 24 h, and the filtrate was replaced every 4 h;

[0137] The solution in the dialysis bag was taken out and freeze-dried for 18 hours to obtain modified carbon quantum dots. The D50 of the modified carbon quantum dots was 5.76 nm.

[0138] The preparation method of component A of this embodiment is:

[0139] Deionized water, BYK194N dispersant, and BYK024 defoamer were added to a dispersion tank and stirred at 500 rpm for 15 minutes to mix evenly. Fumed silica and bentonite were added while stirring and dispersed at 1200 rpm for 20 minutes. After complete mixing, titanium dioxide, barium sulfate, talc, mica powder, zinc aluminum polyphosphate, and modified carbon quantum dots were added in sequence at 800 rpm. After the addition was completed, the speed was increased to 1500 rpm and dispersed for 20 minutes. Then, zirconium beads were added and ground and dispersed for 3 hours. When the slurry fineness was ≤30 μm, the material was filtered to obtain a water-based color paste.

[0140] Add the water-based color paste into the dispersion tank, and then add the water-based epoxy curing agent, polyurea nanofiber, perfluorodecyltriethoxysilane, propylene glycol monomethyl ether, the remaining additives and the remaining deionized water in sequence under stirring at 800 rpm, increase the speed to 1200 rpm and disperse for 30 minutes to obtain component A.

[0141] Example 2

[0142] This embodiment provides a two-component water-based epoxy coating.

[0143] The composition and preparation method of the two-component waterborne epoxy coating of this embodiment are substantially the same as those of Example 1, except that:

[0144] Component A contains 1% polyurea nanofibers, 1% modified carbon quantum dots and 24.3% deionized water, and the contents of the other components remain unchanged.

[0145] Example 3

[0146] This embodiment provides a two-component water-based epoxy coating.

[0147] The composition and preparation method of the two-component waterborne epoxy coating of this embodiment are substantially the same as those of Example 1, except that:

[0148] Component A contains 0.6% polyurea nanofibers, 0.6% modified carbon quantum dots and 25.1% deionized water, and the contents of the other components remain unchanged.

[0149] Comparative Example 1

[0150] This comparative example provides a two-component waterborne epoxy coating.

[0151] The composition and preparation method of the two-component waterborne epoxy coating of this comparative example are basically the same as those of Example 2, except that:

[0152] Component A contains 3% polyurea nanofibers, 3% modified carbon quantum dots and 20.3% deionized water, and the contents of the other components remain unchanged.

[0153] Comparative Example 2

[0154] This comparative example provides a two-component waterborne epoxy coating.

[0155] The composition and preparation method of the two-component waterborne epoxy coating of this comparative example are basically the same as those of Example 2, except that:

[0156] Component A does not contain polyurea nanofibers, the content of deionized water is 24.5%, and the contents of other components remain unchanged.

[0157] Comparative Example 3

[0158] This comparative example provides a two-component waterborne epoxy coating.

[0159] The composition and preparation method of the two-component waterborne epoxy coating of this comparative example are basically the same as those of Example 2, except that:

[0160] Component A does not contain modified carbon quantum dots, the content of deionized water is 24.5%, and the contents of other components remain unchanged.

[0161] Comparative Example 4

[0162] This comparative example provides a two-component waterborne epoxy coating.

[0163] The composition and preparation method of the two-component waterborne epoxy coating of this comparative example are basically the same as those of Example 2, except that:

[0164] In component A, unmodified carbon quantum dots were used instead of modified carbon quantum dots. The unmodified carbon quantum dots were prepared by adding equal weight ratios of ethylenediamine and hexamethylenetetramine to ethanol, reacting at 160°C for 4 hours, dialysis using a 500Da dialysis bag for 12 hours, and then drying in a freeze-drying oven to obtain an unmodified carbon quantum dot powder.

[0165] Comparative Example 5

[0166] This comparative example provides a two-component waterborne epoxy coating.

[0167] The composition and preparation method of the two-component waterborne epoxy coating of this comparative example are basically the same as those of Example 2, except that:

[0168] Component A does not contain modified carbon quantum dots and polyurea nanofibers, the content of deionized water is 26.3%, and the contents of other components remain unchanged.

[0169] Performance testing methods

[0170] Component A and component B were mixed in a mass ratio of 100:35, and applied to the surface of a Q235 steel plate by air spraying at room temperature with a spraying pressure of 0.8 MPa. The mixture was cured at 120°C for 1 hour to form a water-based epoxy coating with a dry film thickness of 100 μm.

[0171] The performance of the waterborne epoxy coating was tested. The salt spray resistance test was conducted according to GB / T10125-2021, using a 5wt% NaCl solution prepared with deionized water for neutral salt spray testing. The water vapor transmission rate test was conducted according to GB / T26253-2010, and the wear resistance test was conducted according to GB / T1768-2006. The normal load was 250g, and the coating mass loss after 5000 revolutions was recorded. The corrosion resistance of the coating was evaluated using electrochemical impedance spectroscopy (EIS). The EIS was conducted using a Gmary Reference 3000 electrochemical workstation, with the coating sample as the working electrode, covering an area of ​​12.57cm. 2 The reference electrode was a saturated calomel electrode, the auxiliary electrode was a platinum sheet, and the test solution was a 3.5wt% NaCl solution. The test was carried out for 30 days, and the electrochemical impedance spectroscopy value on the 30th day was recorded.

[0172] Table 3 Performance test results

[0173]

[0174] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0175] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present invention should be based on the appended claims, and the specification may be used to interpret the content of the claims.

Claims

1. A two-component waterborne epoxy coating, characterized in that: The method comprises component A and component B, wherein the component B comprises a water-based epoxy resin; In parts by mass, the A component includes the following components: 6 to 10 parts of water-based epoxy curing agent; Polyurea nanofiber 0.5 to 2 parts; as well as 0.5 to 2 parts of modified carbon quantum dots; Wherein, the modified carbon quantum dots include modified carbon quantum dots in which hexamethylenetetramine provides the C source and the N source, and thiourea provides the N source and the S source; The polyurea nanofibers contain amine groups.

2. The two-component waterborne epoxy coating according to claim 1, characterized in that: The length of the polyurea nanofibers is 5 μm to 20 μm; and / or The cross-sectional diameter of the polyurea nanofiber is 10 nm to 60 nm; and / or The D50 of the carbon quantum dots is 4 nm to 7 nm.

3. The two-component waterborne epoxy coating according to claim 1, characterized in that: The preparation method of the polyurea nanofiber comprises: Preparation of polyureas by reaction of aliphatic diisocyanates with aliphatic diamines; The polyurea was electrospun and dried.

4. The two-component waterborne epoxy coating according to claim 3, characterized in that: The aliphatic diisocyanate includes hexamethylene diisocyanate; and / or The aliphatic diamine includes ethylenediamine.

5. The two-component waterborne epoxy coating according to claim 1, characterized in that: The preparation method of the modified carbon quantum dots comprises: dissolving thiourea and hexamethylenetetramine in a polar solvent to obtain a first solution; heat-treating the first solution to obtain a second solution; dialyzing the second solution to obtain a retentate solution; The retentate solution is dried.

6. The two-component waterborne epoxy coating according to claim 5, characterized in that: The molecular weight cut-off of the dialysis is 450Da to 550Da; and / or The heat treatment temperature is 160°C to 220°C; and / or The heat treatment time is 4 hours to 24 hours.

7. The two-component waterborne epoxy coating according to any one of claims 1 to 6, characterized in that: In parts by mass, the component A further comprises the following components: 30~50 parts of pigments and fillers; 10 to 15 parts of anti-rust pigment; as well as 1 to 3 parts of silane coupling agent.

8. The two-component waterborne epoxy coating according to claim 7, characterized in that: The anti-rust pigment includes one or more of orthophosphate, modified orthophosphate, polyphosphate, and modified polyphosphate.

9. The two-component waterborne epoxy coating according to claim 7, characterized in that: The pigments and fillers include coloring pigments and body fillers; The coloring pigment includes one or more of iron oxide yellow, iron oxide red, rutile titanium dioxide and carbon black; The physical filler includes one or more of precipitated barium sulfate, mica powder, talc powder, silica powder, heavy calcium carbonate, fumed silica and bentonite.

10. An anti-corrosion coating, characterized in that: The invention is prepared by using the two-component waterborne epoxy coating according to any one of claims 1 to 9.

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