Preparation method of high corrosion-resistant water-based epoxy curing agent

Abstract

The application relates to the technical field of paint, and particularly discloses a preparation method of a high-corrosion-resistance water-based epoxy curing agent. The water-based epoxy curing agent is optimized in the molecular structure to improve the compatibility, water resistance, balance curing rate and pot life of the water-based epoxy curing agent, and to enhance the mechanical property. The water-based epoxy curing agent solves the problem that the corrosion resistance of the water-based epoxy curing agent is still inferior to that of a solvent type system due to the low multi-phase reaction efficiency, the difficulty in completely eliminating the hydrophilic component and the poor film forming compactness.

Description

Technical Field

[0001] This invention belongs to the field of coatings, specifically relating to a method for preparing a highly corrosion-resistant waterborne epoxy curing agent. Background Technology

[0002] Waterborne epoxy curing agents are epoxy resin crosslinking agents that use water as the dispersion medium. Early development primarily employed salt-forming and ionic processes. For example, the H201A / B series improved water solubility by forming salts between amine curing agents and organic acids. However, salt-forming methods often resulted in poor compatibility with epoxy resins, short service life, and poor water resistance. Later, to reduce reliance on acidic salts, waterborne epoxy curing agents began to shift towards non-salt-forming, nonionic products (such as H202A&B and H203A&B), which achieve self-emulsification through hydrophilic structures such as polyoxyethylene segments.

[0003] After more than 20 years of development, modern waterborne epoxy curing agents have approached or even surpassed solvent-based systems in many performance aspects. However, the following problems still exist: 1. Poor compatibility and uneven film formation: The curing agent reacts rapidly with the surface of the epoxy resin dispersed phase particles, while the diffusion rate of curing agent molecules into the resin particles decreases as curing progresses. This results in low cross-linking density within the particles, making it difficult to fuse into a homogeneous film and forming a "sandwich" film, which affects mechanical properties and corrosion resistance. 2. Insufficient water resistance: Excessive hydrophilic segments (such as polyethylene glycol) can lead to water retention, causing the coating to whiten and soften when exposed to a humid environment for a long time. 3. Lower mechanical properties and chemical resistance than solvent-based systems: During the film formation process of waterborne systems, the resin and curing agent separate into micro-regions, and the cross-linking network is not as dense as that of solvent-based systems. Furthermore, the flexible segments introduced to improve water dispersibility also reduce the cross-linking density, resulting in lower hardness, abrasion resistance, and solvent resistance compared to oil-based epoxy.

[0004] To address the aforementioned issues, relevant technical personnel have implemented process improvements. For example, patent CN113444228B discloses a silicone-modified waterborne epoxy curing agent and its preparation and application, as well as a waterborne epoxy high-performance bridge primer and its preparation. By grafting silicone segments onto a polyamine backbone and then emulsifying it with salt, the resulting curing agent, when used in bridge primers, exhibits significantly improved water resistance, salt spray resistance, and early hardness. Another example is patent CN117700692A, which discloses a waterborne epoxy curing agent and its preparation method. This method employs a "two-step chain extension" approach using a macromolecular nonionic amine and an epoxy prepolymer, improving emulsion compatibility and resulting in a rapid increase in initial hardness. However, the aforementioned waterborne epoxy curing agents still suffer from the drawback of hygroscopic free amines and, compared to solvent-based curing agents, exhibit inferior corrosion resistance. Therefore, this invention aims to provide a waterborne epoxy curing agent with low hygroscopicity and high corrosion resistance. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, this invention optimizes the molecular structure to improve the compatibility and water resistance of waterborne epoxy curing agents, balances the curing rate and pot life, and enhances mechanical properties. This solves the problem that the anti-corrosion performance of waterborne epoxy curing agents is still inferior to that of solvent-based systems due to low multiphase reaction efficiency, difficulty in completely eliminating hydrophilic components, and poor film density.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides a method for preparing a highly corrosion-resistant waterborne epoxy curing agent, comprising the following steps: S1. Under inert gas protection, epoxy resin E-51 is dissolved in propylene glycol methyl ether to obtain the base liquid. Ethyleneamine and propylene glycol methyl ether are then heated at 70-90°C. o Stir the mixture thoroughly under temperature C, and add it dropwise to the base solution over 60–90 min. After the addition is complete, keep the mixture warm for 1–3 h to obtain the epoxy amine adduct. S2. Cool the epoxide amine adduct to 50-70°C. o C. Add glycidyl ether dropwise. After the addition is complete, raise the temperature to 70-90°C. o React at C for 1–2 hours, then cool to 50–70°C. o C, to obtain a partially capped intermediate; dissolve triglycidyl isocyanurate in propylene glycol methyl ether, add it to the partially capped intermediate over 20–40 min, and heat to 70–90°C. o The reaction at C lasts for 1–2 hours to obtain the chain-extended intermediate. S3. First, add PEG monoglycidyl ether to the chain extension intermediate and react for 1-2 hours, then add dimethylolbutyric acid and react for 1-2 hours; cool the reaction system to 50-70°C. o C. Add triethylamine and stir for 20–40 minutes, then cool to 30–50°C. o C. Add a nonionic surfactant, shear, and filter to obtain a water-based epoxy curing agent.

[0007] In water-based systems, epoxy resin and curing agent exist as dispersed phases, which makes the curing of the resin surface hinder further internal cross-linking, resulting in insufficient cross-linking density of the coating film and the formation of permeation channels; in addition, the hydrophilic groups of the curing agent remain in the coating film, absorbing moisture and accelerating electrolyte permeation. All these factors reduce the corrosion resistance of water-based epoxy curing agents.

[0008] This invention provides an emulsion-like waterborne epoxy curing agent. First, by constructing an epoxy amine, the primary amine content is reduced, improving compatibility with epoxy resins. Then, glycidyl ether reacts with the remaining primary amine, partially capping the primary amine to extend the pot life while retaining sufficient reactivity. The introduced hydrophobic segments help improve the water resistance and hydrophobicity of the coating film, as well as its compatibility with bisphenol A type epoxy. Subsequently, chain extension yields a branched structure, increasing the crosslinking density and reducing water absorption at the same curing agent dosage. Finally, nonionic hydrophilic segments are introduced through PEG monoglycidyl ether to improve water dispersibility.

[0009] This waterborne epoxy curing agent has several advantages. First, it promotes uniform mixing of the curing agent and epoxy resin through the epoxy amine structure and hydrophobic segments, avoiding the problem of low crosslinking density within particles, forming a homogeneous paint film, and improving mechanical properties. Second, it reduces water adsorption and hydrophilic ion residue through a balanced design of hydrophobic and nonionic hydrophilic segments. Third, it extends the curing agent's pot life at room temperature and enables effective curing in low-temperature and high-humidity environments through partial primary amine end-capping. Fourth, it enhances crosslinking through chain extension, resulting in higher crosslinking density and hydrophobic segments that improve hardness, abrasion resistance, and solvent resistance, and produce a dense paint film structure, thereby enhancing shielding properties and strengthening corrosion resistance.

[0010] In some embodiments, in step S1, the mass ratio of epoxy resin E-51 to ethyleneamine is 1:(0.085~0.105).

[0011] In some embodiments, in step S1, the ethyleneamine comprises diethylenetriamine and triethylenetetramine.

[0012] In some embodiments, the mass ratio of diethylenetriamine to triethylenetetramine is 1:(0.2 to 0.3).

[0013] This invention avoids overheating gel caused by excessive active hydrogen content by controlling the ratio of epoxy resin E-51 to ethyleneamine; at the same time, it improves the regularity of subsequent crosslinking by compounding ethyleneamine.

[0014] In some embodiments, in step S2, the mass ratio of the glycidyl ether to the epoxy resin E-51 in step S1 is (0.6-0.7):1.

[0015] In some embodiments, in step S2, the glycidyl ether comprises phenyl glycidyl ether and butyl glycidyl ether.

[0016] Existing technologies often employ a "simultaneous" or "hydrophilic first, end-capped later" strategy. This invention first uses phenyl glycidyl ether to partially end-cap the amine, forming a hydrophobic benzene ring side group. Then, PEG and dimethylolbutyric acid are sequentially added to achieve a hydrophobic-hydrophilic gradient distribution. This sequence allows the benzene ring to move closer to the amine backbone, thereby increasing the crosslinking density and shielding properties of the cured product. Simultaneously, the long PEG chain migrates outward, balancing water dispersion and corrosion resistance.

[0017] In some embodiments, the mass ratio of the phenyl glycidyl ether to the butyl glycidyl ether is 1:(0.4 to 0.5).

[0018] This invention, based on controlling the epoxy value, adjusts the benzene ring content by compounding glycidyl ether. On the one hand, it utilizes the π-π stacking effect of benzene rings to improve the compatibility between the curing agent and bisphenol A type epoxy; on the other hand, it maintains the water dispersion stability of the waterborne curing agent.

[0019] In some embodiments, in step S2, the mass ratio of the triglycidyl isocyanurate to the epoxy resin E-51 in step S1 is (0.10 to 0.18):1.

[0020] In the chain extension step, the amount of triglycidyl isocyanurate is controlled to ensure that its reaction with the remaining amine hydrogen can form a branched structure without excessive cross-linking, which would lead to difficulties in subsequent emulsification.

[0021] In some embodiments, in step S3, the Mn of the PEG monoglycidyl ether is 450 to 550.

[0022] In some embodiments, the mass ratio of the PEG monoglycidyl ether to the epoxy resin E-51 in step S1 is (0.85–0.95):1. The hydrophilic segment can be adjusted by specifically selecting PEG monoglycidyl ether and its dosage.

[0023] In some embodiments, the specific shearing operation in step S3 is as follows: first, shear at 1200-1800 rpm for 3-8 minutes to obtain a pre-emulsion, then shear at 2200-2800 rpm for 10-20 minutes to refine it, then add 120-180g of deionized water and shear for 10-20 minutes, and finally add 120-180g of deionized water and shear for 5-15 minutes.

[0024] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention optimizes the molecular structure by using compounded ethyleneamine as the base amine, which is pre-reacted with epoxy resin to form an epoxy amine adduct, reducing the primary amine content. Then, the primary amine is partially capped with glycidyl ether, introducing phenyl hydrophobic segments to improve water resistance and hydrophobicity. Subsequently, a branched structure is obtained through chain extension, which increases the crosslinking density under the same curing agent dosage. Finally, nonionic hydrophilic segments are introduced to achieve a balance with hydrophobic segments to reduce water adsorption. This solves the problem of poor anti-corrosion performance caused by low multiphase reaction efficiency and poor film density of waterborne epoxy curing agents.

[0025] 2. Compared with the "simultaneous" or "hydrophilic first, then end-capped" strategies used in traditional technologies, the "hydrophobic first, then hydrophilic" reaction strategy of this invention allows the benzene ring to be closer to the amine skeleton, thereby increasing the crosslinking density and shielding properties of the cured product. At the same time, the long PEG chain migrates outward, taking into account both water dispersion and anti-corrosion performance, thus solving the problem of insufficient anti-corrosion performance caused by the difficulty in completely eliminating hydrophilic components in waterborne epoxy curing agents. Detailed Implementation

[0026] The present invention will be described below with reference to specific implementation schemes. It should be noted that the following embodiments are examples of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope. It is worth noting that, unless otherwise specified, the raw materials used in the following preparation examples and embodiments can be obtained from any commercially available manufacturer.

[0027] Example 1 A method for preparing a highly corrosion-resistant waterborne epoxy curing agent includes the following steps: S1. Under nitrogen protection, 50g of epoxy resin E-51 was dissolved in 35g of propylene glycol methyl ether to obtain the base solution. 3.8g of diethylenetriamine, 1.0g of triethylenetetramine, and 15g of propylene glycol methyl ether were then dissolved at 80°C. o Stir the mixture thoroughly under temperature C, and add it dropwise to the base solution within 80 minutes. After the addition is complete, react for 2 hours to obtain the epoxy amine adduct. S2. Cool the epoxide amine adduct to 60°C. o C. Add 22g of phenyl glycidyl ether and 10g of butyl glycidyl ether dropwise. After the addition is complete, raise the temperature to 80°C. o React at C for 2 hours, then cool to 60°C. o C, to obtain a partially capped intermediate; dissolve 7g of triglycidyl isocyanurate in 5g of propylene glycol methyl ether, add it to the partially capped intermediate over 30 minutes, and heat to 80°C. o After reacting at C for 1 hour, a chain-extended intermediate was obtained. S3. First, add 45g of PEG monoglycidyl ether (Mn=500) to the chain extension intermediate and react for 2 hours, then add 5g of dimethylolbutyric acid and react for 1.5 hours; cool the reaction system to 60°C. o C, add 4g of triethylamine and stir for 30 minutes, then cool to 40°C. o C. Add 4g of nonionic surfactant (APG 0810), first shear at 1500rpm for 5min to obtain a pre-emulsion, then shear at 2500rpm for 15min to refine it, then add 150g of deionized water and shear for 15min, finally add 150g of deionized water and shear for 10min, filter, and you will get the waterborne epoxy curing agent.

[0028] Example 2 A method for preparing a highly corrosion-resistant waterborne epoxy curing agent includes the following steps: S1. Under nitrogen protection, 50g of epoxy resin E-51 was dissolved in 35g of propylene glycol methyl ether to obtain the base solution. 3.5g of diethylenetriamine, 0.75g of triethylenetetramine, and 15g of propylene glycol methyl ether were then dissolved at 90°C. o Stir the mixture thoroughly under temperature C, and add it dropwise to the base solution within 60 minutes. After the addition is complete, react for 1 hour to obtain the epoxy amine adduct. S2. Cool the epoxide amine adduct to 70°C. o C. Add 21.4g of phenyl glycidyl ether and 8.6g of butyl glycidyl ether dropwise. After the addition is complete, heat to 90°C. o React at C for 1 hour, then cool to 70°C. o C, to obtain a partially capped intermediate; dissolve 5g of triglycidyl isocyanurate in 5g of propylene glycol methyl ether, add it to the partially capped intermediate over 20 minutes, and heat to 90°C. o After reacting at C for 1 hour, a chain-extended intermediate was obtained. S3. First, add 45g of PEG monoglycidyl ether (Mn=500) to the chain extension intermediate and react for 1 hour, then add 5g of dimethylolbutyric acid and react for 1 hour; cool the reaction system to 70°C. o C, add 4g of triethylamine and stir for 20 minutes, then cool to 50°C. o C. Add 4g of nonionic surfactant (APG 0810), first shear at 1200rpm for 8min to obtain a pre-emulsion, then shear at 2200rpm for 20min to refine it, then add 120g of deionized water and shear for 10min, finally add 180g of deionized water and shear for 15min, filter, and you will get the waterborne epoxy curing agent.

[0029] Example 3 A method for preparing a highly corrosion-resistant waterborne epoxy curing agent includes the following steps: S1. Under nitrogen protection, 50g of epoxy resin E-51 was dissolved in 35g of propylene glycol methyl ether to obtain the base solution. 4.05g of diethylenetriamine, 1.2g of triethylenetetramine, and 15g of propylene glycol methyl ether were then dissolved at 70°C. o Stir the mixture thoroughly under temperature C, and add it dropwise to the base solution within 90 minutes. After the addition is complete, react for 3 hours to obtain the epoxy amine adduct. S2. Cool the epoxide amine adduct to 50°C. o C. Add 23.4g of phenyl glycidyl ether and 11.6g of butyl glycidyl ether dropwise. After the addition is complete, raise the temperature to 70°C. o React at C for 2 hours, then cool to 50°C. o C, to obtain a partially capped intermediate; dissolve 7g of triglycidyl isocyanurate in 5g of propylene glycol methyl ether, add it to the partially capped intermediate over 40 min, and heat to 70°C. o After reacting at C for 2 hours, a chain-extended intermediate was obtained. S3. First, add 45g of PEG monoglycidyl ether (Mn=500) to the chain extension intermediate and react for 2 hours, then add 9g of dimethylolbutyric acid and react for 2 hours; cool the reaction system to 50°C. o C, add 4g of triethylamine and stir for 40 minutes, then cool to 30°C. o C. Add 4g of nonionic surfactant (APG 0810), first shear at 1800rpm for 3min to obtain a pre-emulsion, then shear at 2800rpm for 10min to refine it, then add 180g of deionized water and shear for 20min, finally add 120g of deionized water and shear for 5min, filter, and you will get the waterborne epoxy curing agent.

[0030] Example 4 This embodiment provides a method for preparing a highly corrosion-resistant waterborne epoxy curing agent. The specific implementation method is the same as in Embodiment 1, except that triethylenetetramine is replaced by an equal amount of diethylenetriamine.

[0031] Example 5 This embodiment provides a method for preparing a highly corrosion-resistant waterborne epoxy curing agent. The specific implementation method is the same as in Embodiment 1, except that butyl glycidyl ether is replaced by an equal amount of phenyl glycidyl ether.

[0032] Example 6 This embodiment provides a method for preparing a highly corrosion-resistant waterborne epoxy curing agent. The specific implementation method is the same as in Embodiment 1, except that the amount of triglycidyl isocyanurate used is 4g.

[0033] Example 7 This embodiment provides a method for preparing a highly corrosion-resistant waterborne epoxy curing agent. The specific implementation method is the same as in Embodiment 1, except that the amount of triglycidyl isocyanurate used is 10g.

[0034] Comparative Example 1 This comparative example provides a method for preparing a highly corrosion-resistant waterborne epoxy curing agent. The specific implementation method is the same as in Example 1, except that steps S2 and S3 are adjusted as follows: S2. Cool the epoxide amine adduct to 60°C. o C. Add 22g of phenyl glycidyl ether and 10g of butyl glycidyl ether dropwise. After the addition is complete, raise the temperature to 80°C. o React at C for 2 hours, then cool to 60°C. o C, to obtain a partially capped intermediate; S3, Heat up to 80 o C. Add 45g of PEG monoglycidyl ether (Mn=500) to the partially capped intermediate and react for 2h, then add 5g of dimethylolbutyric acid and react for 1.5h; cool the reaction system to 60°C. o C, add 4g of triethylamine and stir for 30 minutes, then cool to 40°C. o C. Add 4g of nonionic surfactant (APG 0810), first shear at 1500rpm for 5min to obtain a pre-emulsion, then shear at 2500rpm for 15min to refine it, then add 150g of deionized water and shear for 15min, finally add 150g of deionized water and shear for 10min, filter, and you will get the waterborne epoxy curing agent.

[0035] Performance testing The waterborne epoxy curing agents provided in Examples 1-7 and Comparative Example 1 were tested as follows, and the results are shown in Table 1: 1. Solid content: Weigh 2 g of sample (accurate to 0.1 mg), spread it evenly in a clean aluminum foil tray, and incubate at 105°C. o Dry in a forced-air drying oven for 2 hours, then weigh after cooling to room temperature in a dryer.

[0036] 2. Particle size: Dilute with deionized water to 0.5% solid content, 25 o Dynamic light scattering (DLS) measurement at C.

[0037] 3. Epoxy equivalent: determined according to the hydrochloric acid-acetone method of GB / T 4612-2008.

[0038] 4. Amine value: 0.1 M HClO4-glacial acetic acid non-aqueous titration.

[0039] 5. VOC: Determined by the difference method according to GB / T 23986-2009.

[0040] To further test the performance of the curing agent, the water-based epoxy curing agents provided in Examples 1-7 and Comparative Example 1 were mixed with commercial bisphenol A epoxy emulsion (55% solids content, epoxy equivalent 600, brand not limited) at a ratio of amine hydrogen / epoxy = 1.1:1 to obtain the test sample. The following tests were performed, and the results are shown in Table 2: 1. Potential life: At 25℃, measure the viscosity of the sample every 30 minutes (60 rpm) until it doubles, and record the time.

[0041] 2. Curing time: Referring to GB / T 1728-2020, the sample to be tested was coated on a glass plate with a wet film thickness of 200 µm. The actual drying time was tested every 30 min at 25℃ and 50% RH.

[0042] 3. Mechanical properties of the coating: The sample to be tested was sprayed onto a polished carbon steel plate with a dry film thickness of 25 ± 2 µm. After curing at 25℃ for 7 days, the impact strength was tested according to GB / T 1732, and the cross-cut adhesion was tested according to GB / T 9286.

[0043] 4. Water / Salt spray resistance test: The sample to be tested was sprayed onto a polished carbon steel plate with a dry film thickness of 25 ± 2 µm. It was cured at 25℃ for 7 days and then immersed in deionized water at 25℃ for 7 days and neutral salt spray (5wt% NaCl, 35℃) for 500 h to obtain the water immersion weight gain and the single-sided corrosion width.

[0044] Table 1 Performance Test Results

[0045] Table 2 Performance Test Results

[0046] As shown in Table 1, the curing agent provided by the present invention has strong process stability. Its solid content, particle size, epoxy equivalent and amine value ranges are maintained at 40%±2%, 90-120nm, 450-480 g / eq, and 110-120 mg KOH / g, respectively, and its VOC (volatile organic compounds) is ≤85g / L, which meets the requirements of GB / T38597-2020 waterborne coatings.

[0047] In Table 2, the pot life of Examples 1-4, Example 6, and Comparative Example 1 is 4-5 hours, and the drying speed is 6-8 hours, achieving a balance between curing rate and pot life. Example 1, in particular, exhibits excellent mechanical strength and corrosion resistance. Compared to Example 1, in Example 4, triethylenetetramine is replaced by an equal amount of diethylenetriamine, which is detrimental to the regularity of subsequent crosslinking, affecting film density and leading to decreased water and corrosion resistance. It also slightly reduces impact strength, possibly because crosslinking affects toughness. Further analysis with Comparative Example 1 shows that the absence of branching and chain extension results in a lower crosslinking density with the same amount of curing agent, leading to a significant decrease in mechanical properties and water and corrosion resistance.

[0048] Compared to Example 1, in Example 5, the butyl glycidyl ether was replaced by an equal amount of phenyl glycidyl ether, which had a smaller impact on corrosion resistance. However, the increase in hydrophobic segments affected the water dispersion stability, leading to a decrease in the pot life. In Example 6, the amount of triglycidyl isocyanurate was reduced, resulting in insufficient branching, which affected the crosslinking density and led to a decrease in mechanical properties and water and corrosion resistance. In Example 7, the amount of triglycidyl isocyanurate was increased, resulting in a shorter pot life and a longer complete curing time. This may be due to emulsification difficulties caused by excessive crosslinking, resulting in poor dispersion and thus affecting the performance of the cured product.

[0049] The embodiments and comparative examples described above do not limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing a highly corrosion-resistant water-based epoxy curing agent, characterized in that, Includes the following steps: S1. Under inert gas protection, epoxy resin E-51 is dissolved in propylene glycol methyl ether to obtain the base liquid. Ethyleneamine and propylene glycol methyl ether are then heated at 70-90°C. o Stir the mixture thoroughly under temperature C, and add it dropwise to the base solution over 60–90 min. After the addition is complete, keep the mixture warm for 1–3 h to obtain the epoxy amine adduct. S2. Cool the epoxide amine adduct to 50-70°C. o C. Add glycidyl ether dropwise. After the addition is complete, raise the temperature to 70-90°C. o React at C for 1–2 hours, then cool to 50–70°C. o C, to obtain a partially capped intermediate; dissolve triglycidyl isocyanurate in propylene glycol methyl ether, add it to the partially capped intermediate over 20–40 min, and heat to 70–90°C. o The reaction at C lasts for 1–2 hours to obtain the chain-extended intermediate. S3. First, add PEG monoglycidyl ether to the chain extension intermediate and react for 1-2 hours, then add dimethylolbutyric acid and react for 1-2 hours; cool the reaction system to 50-70°C. o C. Add triethylamine and stir for 20–40 minutes, then cool to 30–50°C. o C. Add a nonionic surfactant, shear, and filter to obtain a water-based epoxy curing agent; In step S1, the ethyleneamine comprises diethylenetriamine and triethylenetetramine; the mass ratio of the diethylenetriamine to the triethylenetetramine is 1:(0.2-0.3). In step S2, the glycidyl ether comprises phenyl glycidyl ether and butyl glycidyl ether; the mass ratio of the phenyl glycidyl ether to the butyl glycidyl ether is 1:(0.4-0.5); In step S3, the Mn of the PEG monoglycidyl ether is 450 to 550.

2. The preparation method of the highly corrosion-resistant waterborne epoxy curing agent according to claim 1, characterized in that, In step S1, the mass ratio of epoxy resin E-51 to ethyleneamine is 1:(0.085~0.105).

3. The preparation method of the highly corrosion-resistant waterborne epoxy curing agent according to claim 1, characterized in that, In step S2, the mass ratio of the glycidyl ether to the epoxy resin E-51 in step S1 is (0.6-0.7):

1.

4. The preparation method of the highly corrosion-resistant waterborne epoxy curing agent according to claim 1, characterized in that, In step S2, the mass ratio of the triglycidyl isocyanurate to the epoxy resin E-51 in step S1 is (0.10~0.18):

1.

5. The preparation method of the highly corrosion-resistant waterborne epoxy curing agent according to claim 1, characterized in that, In step S3, the specific shearing operation is as follows: first, shear at 1200-1800 rpm for 3-8 minutes to obtain a pre-emulsion, then shear at 2200-2800 rpm for 10-20 minutes to refine it, then add 120-180g of deionized water and shear for 10-20 minutes, and finally add 120-180g of deionized water and shear for 5-15 minutes.

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