Epoxy zinc-rich primer for offshore photovoltaic support and preparation method thereof

Abstract

This invention provides an epoxy zinc-rich primer for marine photovoltaic supports and its preparation method, applied in the field of anti-corrosion coatings. The epoxy zinc-rich primer uses an intrinsically modified epoxy resin liquid—with a skeleton containing reversible covalent bonds (disulfide bonds)—as the resin matrix, adding a mixture of flake and spherical zinc powder, and combining it with high-efficiency anti-rust pigments as fillers to form component A. Component B consists of a combination of graphene-modified glass microspheres doped with epoxy curing agent and polyetheramine curing agent. Under room temperature / mild heating conditions, the damaged and broken disulfide bonds in this resin can be dynamically rebuilt, enabling repeated self-repair without the need for microcapsules. It exhibits good compatibility with zinc-rich systems and effectively blocks salt spray and water vapor penetration, significantly improving marine corrosion resistance. The hollow structure, low viscosity, and high bulk density of the glass microspheres significantly increase the volume solids content of the coating to ≥90%, reducing VOCs, decreasing wet film thickness, and accelerating drying. The overall production process is relatively simple, with low energy consumption and minimal emissions during construction.

Description

Technical Field

[0001] This invention relates to the field of anti-corrosion coating technology, and more specifically, to a self-healing, high-volume solids-content epoxy zinc-rich primer for marine photovoltaic supports and its preparation method. Background Technology

[0002] With the accelerated global energy transition and the advancement of "dual-carbon" goals, offshore photovoltaic (PV) power, as an emerging form of clean energy, has experienced rapid development in recent years. However, the high salt spray, strong ultraviolet radiation, and large temperature and humidity fluctuations of the marine environment pose severe challenges to the durability of PV support structures. The corrosion rate of steel supports in the marine environment is several times that on land, and conventional anti-corrosion coatings (such as hot-dip galvanizing and ordinary polyurethane coatings) are insufficient to meet the service life requirement of more than 25 years, resulting in high maintenance costs and safety hazards. For example, traditional hot-dip galvanized supports typically require maintenance every 3-5 years in high-humidity and high-salt environments, and the cost of replacing the supports accounts for 15%-20% of the total investment in the power plant. Therefore, developing high-performance, long-life protective coatings is crucial to ensuring the economic viability and safety of offshore PV projects.

[0003] Currently, epoxy zinc-rich primer for marine photovoltaic (PV) support structures is one of the preferred primers for marine steel structures due to its dual function of cathodic protection and physical shielding. However, existing products generally have the following defects:

[0004] 1) Lack of self-healing ability: The coating is prone to micro-cracks and scratches during transportation, installation and service, which become corrosion channels and accelerate the corrosion of the substrate;

[0005] 2) Low volumetric solids content: Traditional epoxy zinc-rich primers typically have a solids content of ≤80%, resulting in high VOC emissions, thick wet film, slow drying, low efficiency in offshore construction, and a tendency to sag.

[0006] 3) It is difficult to balance corrosion protection and construction performance: Although high zinc powder content improves cathodic protection, it can easily lead to high coating brittleness and insufficient shielding; low zinc powder content will shorten the corrosion protection life.

[0007] Existing self-healing epoxy coatings mostly adopt microcapsule exogenous systems, which have problems such as limited repair times, easy capsule breakage, and poor compatibility with zinc-rich systems. Intrinsic self-healing epoxy research is mostly focused on the general anti-corrosion field, and no integrated epoxy zinc-rich primer with high volume solids content, intrinsic self-healing and long-term anti-corrosion has been developed for offshore photovoltaic brackets.

[0008] Therefore, there is an urgent need to develop an epoxy zinc-rich primer that is intrinsically self-healing, has a volumetric solids content of ≥90%, a long corrosion protection life, and is suitable for the construction and service requirements of offshore photovoltaic brackets.

[0009] CN110358406B discloses a self-healing, high-durability, anti-corrosion composite coating and its preparation method. The intermediate coating incorporates a microcapsule self-healing system, with the capsule core encapsulating repair resin and the capsule wall being an inert protective material. When scratches or microcracks appear on the coating, the microcapsules rupture, and the internal repair fluid automatically flows out to fill the gaps and solidify, completing the damage repair. However, this existing technology can only achieve single-use repair and cannot be repeated.

[0010] CN117820942B discloses a composite coating for base, intermediate, and top layers used in railway bridge steel structures and its preparation method. The epoxy zinc-rich primer contains self-healing microcapsules (external type), which is suitable for heavy-load, vibration, and outdoor corrosion conditions of bridges, and improves the coating's crack resistance, self-healing, and long-term corrosion resistance. However, it is difficult to adapt to the high salt spray, strong ultraviolet radiation, and large temperature and humidity fluctuations at sea.

[0011] CN119081509A discloses a high-solids-content waterborne epoxy zinc-rich primer and its preparation method. It uses waterborne epoxy resin as the film-forming body and combines it with a waterborne curing agent. It has low VOC, is environmentally friendly and pollution-free, and meets the environmental protection requirements of green coating. However, its performance cannot meet the corrosive environment category of marine photovoltaic CX. Summary of the Invention

[0012] In view of this, the present invention aims to propose a self-healing, high-volume solids-content epoxy zinc-rich primer for marine photovoltaic supports and its preparation method, so as to solve the problem that existing self-healing epoxy zinc-rich primers are difficult to adapt to the corrosive environment of marine high salt spray, strong ultraviolet radiation, and large temperature and humidity fluctuations.

[0013] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0014] An epoxy zinc-rich primer for offshore photovoltaic (PV) mounting systems, wherein the epoxy zinc-rich primer is a two-component system, specifically comprising component A and component B, in parts by weight:

[0015] Component A:

[0016] Disulfide bond modified epoxy resin solution: 30-45 parts;

[0017] Mixture of flake zinc powder and spherical zinc powder: 40-55 parts;

[0018] Rust-preventive pigment: 5-10 parts;

[0019] Fumed silica: 1-3 parts;

[0020] Dispersant: 0.5–1.5 parts;

[0021] Defoamer: 0.2–0.8 parts;

[0022] Silane coupling agent: 0.3–1.0 parts;

[0023] Solvent: 2-5 parts;

[0024] Component B:

[0025] Graphene-modified glass microspheres doped with epoxy curing agent: 10-20 parts;

[0026] Polyetheramine curing agent: 5-10 parts;

[0027] Accelerator: 0.5 to 1.5 parts.

[0028] In some embodiments, the disulfide-modified epoxy resin solution is obtained by ring-opening esterification reaction of a dicarboxylic acid containing disulfide bonds with an epoxy group composed of one or both of E51 resin and E44 resin, thereby covalently introducing reversible disulfide bonds into the epoxy resin polymer backbone.

[0029] In some embodiments, the graphene-modified glass microspheres are prepared by surface activation with silane coupling agent KH-560 and in-situ graphene coating process, and then the graphene-modified glass microspheres are doped into the epoxy curing agent at 5-15 wt%.

[0030] In some embodiments, the ratio of flake zinc powder to spherical zinc powder in the mixture of flake zinc powder and spherical zinc powder is 3:7.

[0031] In some embodiments, the anti-rust pigment is one or more of iron-titanium powder, phosphorus iron powder, zinc phosphomolybdate, or calcium phosphosilicate.

[0032] In some embodiments, the solvent is a low-viscosity aromatic hydrocarbon and / or alcohol-ether mixture.

[0033] This invention also provides a method for preparing an epoxy zinc-rich primer for marine photovoltaic supports, comprising the following steps:

[0034] 1) Preparation of component A:

[0035] Add disulfide bond modified epoxy resin liquid, solvent, dispersant, defoamer, and silane coupling agent to a dispersion tank and stir at low speed for 10-20 min.

[0036] Add the mixture of flake zinc powder and spherical zinc powder, high-efficiency rust-preventive pigment, and fumed silica in sequence, and disperse at high speed for 30-50 minutes;

[0037] Grind the material to a fineness of ≤100μm, filter and discharge to obtain component A;

[0038] 2) Preparation of component B:

[0039] Graphene-modified glass microspheres doped with epoxy curing agent, polyetheramine curing agent, and accelerator were added to a reaction vessel and stirred at 60℃~80℃ for 20~40 min.

[0040] Cool to room temperature, filter and discharge to obtain component B;

[0041] Mix components A and B in a mass ratio of 6 to 10:1 and apply by roller or spray on site.

[0042] In some embodiments, the preparation method of the disulfide bond modified epoxy resin liquid is as follows:

[0043] 1) Mix epoxy resin E51 and epoxy resin E44 at a mass ratio of 0 to 5:1, weigh 100 parts and put them into the reaction vessel, heat to 80 to 110°C, and add 8 to 15 parts of 3,3'-dithiodipropionic acid and 0.5 to 1.0 parts of triphenylphosphine catalyst while stirring.

[0044] 2) The reaction is carried out under nitrogen protection at a constant temperature for 4–8 hours, and terminated when the acid value drops to ≤5 mg KOH / g;

[0045] 3) Remove trace amounts of water and unreacted monomers under reduced pressure, cool and discharge to obtain disulfide bond modified epoxy resin liquid.

[0046] In some embodiments, the preparation method of the graphene-modified glass microspheres doped with epoxy curing agent includes:

[0047] 1) Weigh 80 parts of glass microspheres and add them to a mixture of ethanol and propylene glycol methyl ether for ultrasonic dispersion for 50 minutes.

[0048] 2) Add 2-5 parts of silane coupling agent KH-560, adjust the pH to 4-5, and reflux at 120℃ for 2 hours to activate the surface of the glass microspheres;

[0049] 3) Add 1-3 parts of sheet graphene and disperse at high speed for 5 hours to anchor the graphene on the surface of glass microspheres;

[0050] 4) Filter and dry to obtain graphene-modified glass microspheres;

[0051] 5) Add 5-15 parts of graphene-modified glass microspheres to 100 parts of molten epoxy curing agent, disperse at high speed for 30 minutes, and cool to obtain graphene-modified glass microsphere doped curing agent.

[0052] In some embodiments, the method for preparing the mixture of flake zinc powder and spherical zinc powder includes:

[0053] 1) Dry in an oven at 105-120℃ for 2 hours until the moisture content is <0.5%, thus eliminating the agglomeration of zinc powder;

[0054] 2) Weigh 70 parts of spherical zinc powder, stir at low speed at the bottom, then add 30 parts of flake zinc powder in 3 to 5 batches, stirring at high speed for 3 to 5 minutes after each addition. Finally, add 2 to 5 parts of coupling agent KH560 and react for 2 to 4 hours at a temperature of 60 to 90°C and a stirring speed of 300 to 600 r / min.

[0055] 3) After the reaction is complete, the mixture is washed with ethanol 2 to 3 times, and then dried at 80 to 100°C for 8 to 12 hours to obtain a mixture of flake zinc powder and spherical zinc powder.

[0056] Compared with existing technologies, the beneficial effects of this invention—a self-healing, high-volume solids-content epoxy zinc-rich primer for marine photovoltaic supports and its preparation method—are as follows:

[0057] 1) Intrinsic self-healing, high repair efficiency and multiple repairs (repair rate of microcracks / scratches ≥85% at room temperature for 24 hours, repair rate of microcracks / scratches ≥95% after heating (70℃) for 1 hour): The polymer skeleton contains reversible disulfide bonds, eliminating the need for microcapsules, and can be repaired at room temperature. It can be repaired multiple times without failure, significantly extending the coating life.

[0058] 2) High volumetric solids content, green and environmentally friendly, and efficient construction: Volumetric solids content ≥90%, low VOC (VOC≤100g / L), thin wet film (wet film thickness can be reduced by 40%), fast drying (drying speed increased by 30%), suitable for large-scale construction of offshore photovoltaic support structures;

[0059] 3) Excellent marine corrosion resistance: The synergistic effect of graphene-glass microsphere three-dimensional shielding and zinc powder cathodic protection significantly improves salt spray resistance (salt spray resistance ≥5000h, adhesion ≥5MPa), damp heat resistance, and aging resistance, meeting the 20-year marine corrosion resistance requirements.

[0060] 4) Good compatibility and high stability: Disulfide bond modified epoxy has good compatibility with zinc-rich systems and graphene modified curing agents, with a storage period of ≥12 months and good construction stability.

[0061] The preparation method of this invention is simple, the process parameters are easy to control, and it can be industrialized, resulting in good economic and social benefits. Detailed Implementation

[0062] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below.

[0063] A self-healing, high-volume solids epoxy zinc-rich primer for offshore photovoltaic supports is a two-component system. Its specific components include component A (resin base) and component B (curing agent), in parts by weight:

[0064] Component A (resin base):

[0065] Disulfide bond modified epoxy resin solution: 30-45 parts

[0066] Mixture of flake zinc powder and spherical zinc powder: 40-55 parts

[0067] High-efficiency rust-preventive pigment: 5-10 parts

[0068] Fumed silica: 1-3 parts

[0069] Dispersant: 0.5–1.5 parts

[0070] Defoamer: 0.2–0.8 parts

[0071] Silane coupling agent: 0.3–1.0 parts

[0072] Low viscosity aromatic hydrocarbon and / or alcohol ether mixed solvent: 2-5 parts

[0073] Component B (curing agent):

[0074] Graphene-modified glass microspheres doped with epoxy curing agent: 10-20 parts

[0075] Polyetheramine curing agent: 5-10 parts

[0076] Accelerator: 0.5–1.5 parts

[0077] The disulfide bond modified epoxy resin solution is prepared by ring-opening esterification reaction of dicarboxylic acid (3,3'-dithiodipropionic acid) containing disulfide bonds with epoxy groups composed of one or two of E51 resin and E44 resin, thereby covalently introducing reversible disulfide bonds (—S—S—) into the epoxy resin polymer backbone, thus obtaining an intrinsically self-healing modified epoxy solution.

[0078] The graphene-modified glass microspheres in component B are prepared by surface activation with silane coupling agent KH-560 and in-situ graphene coating process. The graphene-modified glass microspheres are then doped into the epoxy curing agent (methylhexahydrophthalic anhydride / polyamide composite system) at 5-15 wt%.

[0079] The ratio of flake zinc powder to spherical zinc powder in the mixture of flake zinc powder and spherical zinc powder is 3:7. The mixture is made by premixing 800-1200 mesh flake zinc powder and 500-800 mesh spherical zinc powder in a specific ratio and using a specific process.

[0080] High-efficiency rust-preventing pigments are one or more of the following: iron-titanium powder, phosphorus iron powder, zinc phosphomolybdate, or calcium phosphosilicate.

[0081] The fumed silica is one or more of R972, A200, or M-5.

[0082] The dispersant is one or more of BYK-203, BYK-220S, EFKA4010 or EFKA4665.

[0083] The defoamer is one or more of BYK-A530, 6800, and FN.

[0084] The silane coupling agent is one or more of KH560, KH550, GX-560 or A-1100.

[0085] The low-viscosity aromatic / alcohol ether mixed solvent is one or more of xylene, n-butanol, propylene glycol methyl ether, and butyl acetate.

[0086] The polyetheramine curing agent is one or more of Covestro Desmophen® 1420, Huntsman D230, Chenguang New Materials MG-698, Huntsman T-403 or Huntsman D-400.

[0087] The accelerator is one or more of K54 and DMP-30.

[0088] As part of the embodiments of the present invention, a method for preparing a self-healing, high-volume solids-content epoxy zinc-rich primer for marine photovoltaic supports is also provided, comprising the following steps:

[0089] Preparation method of disulfide bond modified epoxy resin liquid:

[0090] 1) Mix epoxy resin E51 and epoxy resin E44 at a mass ratio of 0 to 5:1, weigh 100 parts and put them into the reaction vessel, heat to 80 to 110°C, and add 8 to 15 parts of 3,3'-dithiodipropionic acid and 0.5 to 1.0 parts of triphenylphosphine catalyst while stirring.

[0091] 2) The reaction is carried out under nitrogen protection at a constant temperature for 4–8 hours, and terminated when the acid value drops to ≤5 mg KOH / g;

[0092] 3) Remove trace amounts of water and unreacted monomers under reduced pressure, cool and discharge to obtain disulfide bond modified epoxy resin liquid.

[0093] Preparation method of graphene-modified glass microspheres doped with epoxy curing agent:

[0094] 1) Weigh 80 parts of glass microspheres (particle size 20-70μm), add them to a mixture of ethanol and propylene glycol methyl ether and ultrasonically disperse them for 50 min.

[0095] 2) Add 2-5 parts of silane coupling agent KH-560, adjust the pH to 4-5, and reflux at 120℃ for 2 hours to activate its surface;

[0096] 3) Add 1-3 parts of sheet graphene (sheet diameter 0.5-2μm, thickness 1-4nm), disperse at high speed for 5h, so that the graphene is anchored on the surface of glass microspheres;

[0097] 4) Filter and dry to obtain graphene-modified glass microspheres;

[0098] 5) Add 5-15 parts of graphene-modified glass microspheres to 100 parts of molten epoxy curing agent, disperse at high speed for 30 minutes, and cool to obtain graphene-modified glass microsphere doped curing agent.

[0099] Preparation method of a mixture of flake zinc powder and spherical zinc powder (ratio 3:7):

[0100] 1. Dry in an oven at 105-120℃ for 2 hours until the moisture content is less than 0.5%, thus eliminating the agglomeration of zinc powder;

[0101] 2. Weigh 70 parts of spherical zinc powder (heavy and easy to sink), stir at low speed (300-500 rpm) as a base, then add 30 parts of flake zinc powder in 3-5 batches, stirring at high speed (1000-1500 rpm) for 3-5 minutes after each addition. Finally, add 2-5 parts of coupling agent KH560 and react for 2-4 hours at a temperature of 60-90℃ and a stirring speed of 300-600 r / min.

[0102] 3. After the reaction is complete, wash the mixture with ethanol 2 to 3 times, and then dry it at 80 to 100°C for 8 to 12 hours to obtain a mixture of flake zinc powder and spherical zinc powder (in a ratio of 3:7).

[0103] The preparation methods for primers include:

[0104] 1) Preparation of component A:

[0105] Add the disulfide bond modified epoxy resin liquid, solvent, dispersant, defoamer, and silane coupling agent to the dispersion vessel and stir at low speed (200-800 r / min) for 10-20 min;

[0106] Add the mixture of flake zinc powder and spherical zinc powder, high-efficiency rust-preventive pigment, and fumed silica in sequence, and disperse at high speed (1500~3000r / min) for 30~50min;

[0107] Grind the material to a fineness of ≤100μm, filter it, and obtain component A.

[0108] 2) Preparation of component B:

[0109] Graphene-modified glass microspheres, polyetheramine curing agent, and accelerator were added to a reaction vessel and stirred at 60℃~80℃ for 20~40 min.

[0110] Cool to room temperature, filter and discharge to obtain component B.

[0111] Mix components A and B in a mass ratio of 6 to 10:1 and apply by roller or spray on site.

[0112] The coating prepared by this invention uses an intrinsically modified epoxy resin liquid-skeleton containing reversible covalent bonds (disulfide bonds) as the resin matrix, adds a mixture of flake zinc powder and spherical zinc powder, and combines it with a high-efficiency anti-rust pigment as filler to form component A. Component B consists of a combination of graphene-modified glass microspheres doped with epoxy curing agent and polyetheramine curing agent. The self-healing, high-volume solids epoxy zinc-rich primer for marine photovoltaic brackets has the following characteristics: (1) Under room temperature / mild heating (60-80℃) conditions, the damaged and broken disulfide bonds of the resin can be dynamically rebuilt, achieving repeated self-repair without microcapsules, and it has good compatibility with zinc-rich systems; (2) Graphene constructs a three-dimensional conductive-shielding network in the cured film, which not only enhances the cathodic protection efficiency of zinc powder, but also blocks the penetration of salt spray and water vapor, greatly improving the marine anti-corrosion performance: salt spray resistance ≥5000 hours, service life ≥25 years; (3) The hollow structure, low viscosity, and high packing density of glass microspheres significantly increase the volume solids content of the coating to ≥90%, reduce VOC, reduce wet film thickness, and accelerate drying; (4) The production process is relatively simple, with low production energy consumption and low construction emissions.

[0113] Example 1

[0114] The preparation methods of disulfide bond modified epoxy resin liquid include:

[0115] 1) Mix epoxy resin E51 and epoxy resin E44 at a mass ratio of 2:1, weigh 100 parts and put them into the reaction vessel, heat to 100℃, and add 11 parts of 3,3'-dithiodipropionic acid and 0.7 parts of triphenylphosphine catalyst while stirring.

[0116] 2) The reaction was carried out under nitrogen protection at a constant temperature for 6 hours, and the reaction was terminated when the acid value dropped to 4 mg KOH / g;

[0117] 3) Remove trace amounts of water and unreacted monomers under reduced pressure, cool and discharge to obtain disulfide bond modified epoxy resin liquid.

[0118] The preparation methods of graphene-modified glass microspheres doped with epoxy curing agents include:

[0119] 1) Weigh 80 parts of glass microspheres (30μm in diameter), add them to a mixture of ethanol and propylene glycol methyl ether and ultrasonically disperse them for 50 minutes.

[0120] 2) Add 3.5 parts of silane coupling agent KH-560, adjust the pH to 4, and reflux at 120℃ for 2 hours to activate its surface;

[0121] 3) Add 3 parts of few-layer graphene (sheet diameter 1.5μm, thickness 3nm) and disperse at high speed for 5h to anchor the graphene on the surface of the microspheres.

[0122] 4) Filter and dry to obtain graphene-modified glass microspheres;

[0123] 5) Add 10 parts of graphene-modified glass microspheres to 100 parts of molten epoxy curing agent, disperse at high speed for 30 minutes, and cool to obtain graphene-modified glass microsphere doped curing agent.

[0124] Preparation method of a mixture of flake zinc powder and spherical zinc powder (ratio 3:7):

[0125] 1. Dry in an oven at 110℃ for 2 hours until the moisture content is below 0.5%, thus eliminating the agglomeration of zinc powder;

[0126] 2. Weigh 70 parts of spherical zinc powder (heavy and easy to sink), stir at low speed (500 rpm), add 30 parts of flake zinc powder in 5 portions, stir at high speed (1100 rpm) for 4 minutes after each addition, and finally add 2.5 parts of coupling agent KH560. React at 90℃ and 600 r / min for 3.5 hours.

[0127] 3. After the reaction is complete, the mixture is washed three times with ethanol and then dried at 100°C for 10 hours to obtain a mixture of flake zinc powder and spherical zinc powder.

[0128] Example 2

[0129] A self-healing, high-volume solids epoxy zinc-rich primer formulation for offshore photovoltaic (PV) supports is shown in Table 1. The preparation method of the epoxy zinc-rich primer is as follows:

[0130] 1) Preparation of Component A

[0131] Add the disulfide bond modified epoxy resin liquid, solvent, dispersant, defoamer, and silane coupling agent to the dispersion vessel and stir at low speed (600 r / min) for 10 min;

[0132] Zinc powder, high-efficiency rust-preventing pigment, and fumed silica were added sequentially and dispersed at high speed (1800 r / min) for 30 min.

[0133] Grind the material to a fineness of ≤100μm, filter it, and obtain component A.

[0134] 2) Preparation of component B:

[0135] Graphene-modified glass microspheres, polyetheramine curing agent, and accelerator were added to a reaction vessel and stirred at 60°C for 20 minutes.

[0136] Cool to room temperature, filter and discharge to obtain component B.

[0137] Mix components A and B in a mass ratio of 10:1 and apply by roller or spray on-site.

[0138] Table 1 Coating Formulation

[0139]

[0140] Example 3

[0141] A self-healing, high-volume solids epoxy zinc-rich primer formulation for offshore photovoltaic (PV) supports is shown in Table 2. The preparation method of the epoxy zinc-rich primer is as follows:

[0142] 1) Preparation of Component A

[0143] Add the disulfide bond modified epoxy resin liquid, solvent, dispersant, defoamer, and silane coupling agent to the dispersion vessel and stir at low speed (800 r / min) for 15 min.

[0144] Zinc powder, high-efficiency rust-preventing pigment, and fumed silica were added sequentially and dispersed at high speed (1500 r / min) for 50 min;

[0145] Grind the material to a fineness of ≤100μm, filter it, and obtain component A.

[0146] 2) Preparation of component B:

[0147] Graphene-modified glass microspheres, polyetheramine curing agent, and accelerator were added to a reaction vessel and stirred at 80°C for 22 minutes.

[0148] Cool to room temperature, filter and discharge to obtain component B.

[0149] Mix components A and B at a mass ratio of 7.5:1 and apply by roller or spray on-site.

[0150] Table 2 Coating Formulation

[0151]

[0152] Example 4

[0153] A self-healing, high-volume solids epoxy zinc-rich primer formulation for offshore photovoltaic (PV) supports is shown in Table 3. The preparation method of the epoxy zinc-rich primer is as follows:

[0154] 1) Preparation of Component A

[0155] Add the disulfide bond modified epoxy resin liquid, solvent, dispersant, defoamer, and silane coupling agent to the dispersion vessel and stir at low speed (750 r / min) for 13 min.

[0156] Zinc powder, high-efficiency rust-preventing pigment, and fumed silica were added sequentially and dispersed at high speed (2550 r / min) for 48 min;

[0157] Grind the material to a fineness of ≤100μm, filter it, and obtain component A.

[0158] 2) Preparation of component B:

[0159] Graphene-modified glass microspheres, polyetheramine curing agent, and accelerator were added to a reaction vessel and stirred at 69°C for 27 minutes.

[0160] Cool to room temperature, filter and discharge to obtain component B.

[0161] Mix components A and B in a 6:1 mass ratio and apply by roller or spray on-site.

[0162] Table 3 Coating Formulation

[0163]

[0164] The performance indicators of the product of this invention are shown in Table 4:

[0165] Table 4 Performance Indicators of the Primer for the Invention Product

[0166]

[0167] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. An epoxy zinc-rich primer for offshore photovoltaic support structures, characterized in that, The epoxy zinc-rich primer is a two-component system, specifically comprising component A and component B, in parts by weight: Component A: Disulfide bond modified epoxy resin solution: 30-45 parts; Mixture of flake zinc powder and spherical zinc powder: 40-55 parts; Rust-preventive pigment: 5-10 parts; Fumed silica: 1-3 parts; Dispersant: 0.5–1.5 parts; Defoamer: 0.2–0.8 parts; Silane coupling agent: 0.3–1.0 parts; Solvent: 2-5 parts; Component B: Graphene-modified glass microspheres doped with epoxy curing agent: 10-20 parts; Polyetheramine curing agent: 5-10 parts; Accelerator: 0.5 to 1.5 parts.

2. The epoxy zinc-rich primer according to claim 1, characterized in that, The disulfide-modified epoxy resin solution is obtained by ring-opening esterification reaction of a dicarboxylic acid containing disulfide bonds with an epoxy group composed of one or two of E51 resin and E44 resin, thereby covalently introducing reversible disulfide bonds into the epoxy resin polymer backbone.

3. The epoxy zinc-rich primer according to claim 1, characterized in that, The graphene-modified glass microspheres doped with epoxy curing agent are prepared by surface activation with silane coupling agent KH-560 and in-situ graphene coating process. Then, the graphene-modified glass microspheres are doped into the epoxy curing agent at 5-15 wt%.

4. The epoxy zinc-rich primer according to claim 1, characterized in that, The ratio of flaky zinc powder to spherical zinc powder in the mixture of flaky zinc powder and spherical zinc powder is 3:

7.

5. The epoxy zinc-rich primer according to claim 1, characterized in that, The anti-rust pigment is one or more of the following: iron-titanium powder, phosphorus iron powder, zinc phosphomolybdate, or calcium phosphosilicate.

6. The epoxy zinc-rich primer according to claim 1, characterized in that, The solvent is a mixture of low-viscosity aromatic hydrocarbons and / or alcohol ethers.

7. A method for preparing an epoxy zinc-rich primer for offshore photovoltaic supports, characterized in that, Includes the following steps: 1) Preparation of component A: Add disulfide bond modified epoxy resin liquid, solvent, dispersant, defoamer, and silane coupling agent to a dispersion tank and stir at low speed for 10-20 min. Add the mixture of flake zinc powder and spherical zinc powder, high-efficiency rust-preventive pigment, and fumed silica in sequence, and disperse at high speed for 30-50 minutes; Grind the material to a fineness of ≤100μm, filter and discharge to obtain component A; 2) Preparation of component B: Graphene-modified glass microspheres doped with epoxy curing agent, polyetheramine curing agent, and accelerator were added to a reaction vessel and stirred at 60℃~80℃ for 20~40 min. Cool to room temperature, filter and discharge to obtain component B; Mix components A and B in a mass ratio of 6 to 10:1 and apply by roller or spray on site.

8. The method for preparing the epoxy zinc-rich primer according to claim 7, characterized in that, Preparation method of the disulfide bond modified epoxy resin liquid: 1) Mix epoxy resin E51 and epoxy resin E44 at a mass ratio of 0 to 5:1, weigh 100 parts and put them into the reaction vessel, heat to 80 to 110°C, and add 8 to 15 parts of 3,3'-dithiodipropionic acid and 0.5 to 1.0 parts of triphenylphosphine catalyst while stirring. 2) The reaction is carried out under nitrogen protection at a constant temperature for 4–8 hours, and terminated when the acid value drops to ≤5 mg KOH / g; 3) Remove trace amounts of water and unreacted monomers under reduced pressure, cool and discharge to obtain disulfide bond modified epoxy resin liquid.

9. The method for preparing the epoxy zinc-rich primer according to claim 7, characterized in that, The preparation method of the graphene-modified glass microspheres doped with epoxy curing agent includes: 1) Weigh 80 parts of glass microspheres and add them to a mixture of ethanol and propylene glycol methyl ether for ultrasonic dispersion; 2) Add 2-5 parts of silane coupling agent KH-560, adjust the pH to 4-5, and reflux at 120℃ for 2 hours to activate the surface of the glass microspheres; 3) Add 1-3 parts of sheet graphene and disperse at high speed for 5 hours to anchor the graphene on the surface of glass microspheres; 4) Filter and dry to obtain graphene-modified glass microspheres; 5) Add 5-15 parts of graphene-modified glass microspheres to 100 parts of molten epoxy curing agent, disperse at high speed for 30 minutes, and cool to obtain graphene-modified glass microsphere doped curing agent.

10. The method for preparing the epoxy zinc-rich primer according to claim 7, characterized in that, The preparation method of the mixture of flake zinc powder and spherical zinc powder includes: 1) Dry in an oven at 105-120℃ for 2 hours until the moisture content is <0.5%, thus eliminating the agglomeration of zinc powder; 2) Weigh 70 parts of spherical zinc powder, stir at low speed at the bottom, then add 30 parts of flake zinc powder in 3 to 5 batches, stirring at high speed for 3 to 5 minutes after each addition. Finally, add 2 to 5 parts of coupling agent KH560 and react for 2 to 4 hours at a temperature of 60 to 90°C and a stirring speed of 300 to 600 r / min. 3) After the reaction is complete, the mixture is washed with ethanol 2 to 3 times, and then dried at 80 to 100°C for 8 to 12 hours to obtain a mixture of flake zinc powder and spherical zinc powder.

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