A water-based epoxy-polyether copolymer resin capable of improving the corrosion resistance of coatings and a preparation method thereof

Abstract

The present invention discloses a water-based epoxy-polyether copolymer resin capable of improving the corrosion resistance of coatings and a preparation method thereof, relating to the technical field of polymer materials. The water-based epoxy-polyether copolymer resin includes a dispersion prepared by the following steps: first, synthesizing an epoxy prepolymer containing a phosphate group, then introducing a polyether segment and a short-chain alkane group, and finally neutralizing and dispersing. The present invention prepares a water-based epoxy-polyether copolymer resin, and introduces phosphate groups and short-chain alkane groups during the preparation process. The resulting copolymer has the common advantages of epoxy resin and polyether. The present invention significantly improves the corrosion resistance of the material when used in coatings through the synergistic effect of short-chain alkane groups, phosphate groups, and the structural properties of the water-based epoxy-polyether copolymer resin.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, in particular to a water-based epoxy-polyether copolymer resin capable of improving the corrosion resistance of coatings and a preparation method thereof. Background Art

[0002] Epoxy resin, a high molecular weight polymer, is a general term for polymers containing two or more epoxy groups. It is a condensation product of epichlorohydrin and bisphenol A or polyols. It is widely favored for its excellent physical, mechanical, and electrical insulation properties, strong bonding properties, and flexibility. Epoxy resin is widely used in a variety of applications, including coatings, composite materials, and adhesives. However, epoxy resin also has some disadvantages, such as its high cost, especially when high quality is required. It is also prone to cracking and discoloration, especially under high temperatures and UV exposure, which not only affects its aesthetics but also reduces its lifespan and performance. Epoxy resin is sensitive to heat and UV rays and is prone to oxidation and aging over long-term use. Furthermore, its waste disposal is difficult and may cause environmental pollution. Polyether is an organic polymer compound with multiple ether bonds in its main chain, typically formed by the polymerization of polyols and ethylene oxide. Polyethers are characterized by low toxicity, low irritation, water solubility, and corrosion resistance, leading to their widespread application in the petroleum, chemical, pharmaceutical, and textile industries. However, polyethers also have limitations, such as being generally insoluble in mineral oil, having limited solubility and sensitivity to additives, and being compatible only with specific materials.

[0003] Given the respective advantages and disadvantages of epoxy resins and polyethers, the development of epoxy-polyether copolymer resins is particularly necessary. However, research in this area is still blank. Summary of the Invention

[0004] In response to the above-mentioned existing situation, the present invention provides a water-based epoxy-polyether copolymer resin and a preparation method thereof, and prepares an epoxy-polyether copolymer, which combines the advantages of epoxy resin and polyether. By introducing phosphate groups and short-chain alkane groups into the epoxy-polyether copolymer resin, through the synergistic effect of the short-chain alkane groups, phosphate groups, and the properties of the water-based epoxy-polyether copolymer resin itself, we overcome the problem that the corrosion resistance of the simply prepared epoxy-polyether copolymer resin still does not meet the expectations during the research and development process, and greatly improve the corrosion resistance of the material.

[0005] To achieve the above objectives, the present invention is implemented through the following technical scheme: a water-based epoxy-polyether copolymer resin capable of improving the corrosion resistance of coatings, the water-based epoxy-polyether copolymer resin comprising a dispersion prepared by the following steps: first synthesizing an epoxy prepolymer containing a phosphate group, then introducing a polyether chain segment and a short-chain alkane group, and finally neutralizing and dispersing.

[0006] The method for preparing the water-based epoxy-polyether copolymer resin capable of improving the corrosion resistance of the coating specifically comprises:

[0007] S1. Preparing an epoxy prepolymer containing a phosphate group: reacting an epoxy resin with a diluent, a phosphatizing agent, and a catalyst to obtain an epoxy prepolymer containing a phosphate group;

[0008] S2. Introducing polyether segments and short-chain alkane groups: The obtained prepolymer is mixed with a polyether polyol, a short-chain alkane group introducing agent, a chain extender, and a catalyst to react to obtain a copolymer containing polyether segments and short-chain alkane groups;

[0009] S3. Water-based: the obtained copolymer is mixed with a neutralizing agent and then deionized water is added for emulsification to form a water-based epoxy-polyether copolymer resin emulsion.

[0010] Preferably, the molar ratio of the epoxy resin to the diluent in S1 is (2-3):1.

[0011] Preferably, the molar ratio of the phosphating agent to the epoxy resin in S1 is 0.1:1.

[0012] Preferably, the amount of the catalyst in S1 is 0.5-0.8 wt % of the epoxy resin.

[0013] Preferably, the reaction in S1 is carried out at a temperature of 100-120°C for 2-3 hours. Specifically, the following steps are performed: Mix a bisphenol A epoxy resin and an epoxy resin reactive diluent. Add a phosphating agent and stir until uniformly mixed. Add a catalyst and stir again until uniformly mixed. The reaction is continued at 100-120°C for 2-3 hours to obtain an epoxy prepolymer containing phosphate groups.

[0014] Preferably, the diluent in S1 includes butyl glycidyl ether; the phosphating agent includes triethyl phosphate; and the catalyst includes triphenylphosphine.

[0015] Preferably, the molar ratio of the epoxy prepolymer containing phosphate groups to the polyether polyol in S1 is 2:1.

[0016] Preferably, the molar ratio of the short-chain alkane group introducing agent in S2 to the polyether polyol is 0.05:1.

[0017] Preferably, the molar ratio of the chain extender to the polyether polyol in S2 is 0.1:1.

[0018] Preferably, the catalyst in S2 accounts for 0.1-0.3 wt% of the total reaction system.

[0019] Preferably, the reaction in step S2 is carried out at a temperature of 80-100°C for 1-2 hours. Specifically, the epoxy prepolymer containing phosphate groups is mixed with a polyether polyol. A short-chain alkane group-introducing agent and a chain extender are added and stirred uniformly. A catalyst is added and stirred again. The reaction is continued at 80-100°C for 1-2 hours to obtain a copolymer containing polyether segments and short-chain alkane groups.

[0020] Preferably, the polyether polyol in S2 includes polypropylene glycol; the short-chain alkane group introducing agent includes n-propanol; the chain extender includes a diamine; and the catalyst includes dibutyltin dilaurate.

[0021] Preferably, the mass ratio of the neutralizer to the copolymer in S3 is (0.1-0.5):1.

[0022] Preferably, the mass ratio of deionized water to copolymer in S3 is (5-8):1.

[0023] Preferably, the neutralizing agent in S3 comprises dimethylethanolamine. The specific operation of S3 is as follows: mixing the copolymer containing polyether segments and short-chain alkane groups with the neutralizing agent and neutralizing to a neutral or slightly alkaline state. Deionized water is slowly added under high-speed stirring to emulsify the mixture. Stirring is continued until a stable aqueous emulsion is formed.

[0024] The present invention provides a high-temperature resistant waterborne polyurethane resin and a preparation method thereof. It has the following beneficial effects:

[0025] Phosphate groups can form stable chemical bonds on metal surfaces, effectively improving the adhesion of waterborne epoxy resins to metal surfaces. This enhanced adhesion reduces gaps between the coating and the metal substrate, reducing the chance of penetration by corrosive media. Phosphate groups contain hydroxyl groups, which increase the hydrophilicity of waterborne epoxy resins. This facilitates coating spreading and wetting on the metal surface, resulting in a more uniform and dense coating, improved barrier properties, and ultimately enhanced corrosion resistance. During the curing process, phosphate groups provide more curing sites, helping to form a stronger and more cross-linked coating structure, thereby improving the coating's physical properties and corrosion resistance. The introduction of alkane groups can alter the molecular structure of the waterborne epoxy-polyether copolymer resin, potentially making it more distorted and complex. This structural change can affect intermolecular interactions, thereby modifying the coating's solubility, boiling point, melting point, and other properties, positively impacting its corrosion resistance. Short-chain alkane groups can also influence the coating's chemical reactivity by altering the molecule's hydrophobicity and hydrophilicity. This regulation can optimize the interaction between the coating and the corrosive medium, reduce the penetration and diffusion of the corrosive medium in the coating, and thus improve the corrosion resistance of the coating. In addition, the introduction of multiple groups may produce a certain synergistic effect, thereby significantly improving the corrosion resistance of the coating. DETAILED DESCRIPTION

[0026] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] Example 1 Preparation of waterborne epoxy-polyether copolymer resin:

[0028] S1. Prepare an epoxy prepolymer containing a phosphate group: Mix a bisphenol A epoxy resin and an epoxy resin reactive diluent. Add a phosphating agent and stir until uniform. Add a catalyst and stir again until uniform. React at 100-120°C for 2-3 hours to obtain an epoxy prepolymer containing a phosphate group.

[0029] S2. Introducing polyether segments and short-chain alkane groups: Mix the phosphate-containing epoxy prepolymer with the polyether polyol. Add a short-chain alkane group-introducing agent and a chain extender, and stir evenly. Add a catalyst and stir again. React at 80-100°C for 1-2 hours to obtain a copolymer containing polyether segments and short-chain alkane groups.

[0030] S3. Water-Based Emulsion: Mix the copolymer containing polyether segments and short-chain alkane groups with a neutralizer and neutralize to a neutral or slightly alkaline state. Slowly add deionized water while stirring at high speed to emulsify the mixture. Continue stirring until a stable aqueous emulsion is formed.

[0031] The molar ratio of the epoxy resin to the diluent in S1 is 2:1.

[0032] The molar ratio of the phosphating agent to the epoxy resin in S1 is 0.1:1.

[0033] The amount of catalyst used in S1 is 0.5 wt% of the epoxy resin.

[0034] The diluent in S1 includes butyl glycidyl ether; the phosphating agent includes triethyl phosphate; and the catalyst includes triphenylphosphine.

[0035] The molar ratio of the epoxy prepolymer containing phosphate groups to the polyether polyol in S1 is 2:1.

[0036] The molar ratio of the short-chain alkane group introducing agent in S2 to the polyether polyol is 0.05:1.

[0037] The molar ratio of the chain extender to the polyether polyol in S2 is 0.1:1.

[0038] The catalyst in S2 accounts for 0.1 wt% of the total amount of the reaction system.

[0039] S2 The polyether polyol includes polypropylene glycol; the short-chain alkane group introducing agent includes n-propanol; the chain extender includes a diamine; and the catalyst includes dibutyltin dilaurate.

[0040] The mass ratio of the neutralizer to the copolymer in S3 is 0.1:1.

[0041] The mass ratio of deionized water to copolymer in S3 is 5:1.

[0042] The neutralizing agent in S3 includes dimethylethanolamine.

[0043] Example 2 Preparation of waterborne epoxy-polyether copolymer resin:

[0044] S1. Prepare an epoxy prepolymer containing a phosphate group: Mix a bisphenol A epoxy resin and an epoxy resin reactive diluent. Add a phosphating agent and stir until uniform. Add a catalyst and stir again until uniform. React at 100-120°C for 2-3 hours to obtain an epoxy prepolymer containing a phosphate group.

[0045] S2. Introducing polyether segments and short-chain alkane groups: Mix the phosphate-containing epoxy prepolymer with the polyether polyol. Add a short-chain alkane group-introducing agent and a chain extender, and stir evenly. Add a catalyst and stir again. React at 80-100°C for 1-2 hours to obtain a copolymer containing polyether segments and short-chain alkane groups.

[0046] S3. Water-Based Emulsion: Mix the copolymer containing polyether segments and short-chain alkane groups with a neutralizer and neutralize to a neutral or slightly alkaline state. Slowly add deionized water while stirring at high speed to emulsify the mixture. Continue stirring until a stable aqueous emulsion is formed.

[0047] The molar ratio of the epoxy resin to the diluent in S1 is 3:1.

[0048] The molar ratio of the phosphating agent to the epoxy resin in S1 is 0.1:1.

[0049] The amount of catalyst used in S1 is 0.8 wt % of the epoxy resin.

[0050] The diluent in S1 includes butyl glycidyl ether; the phosphating agent includes triethyl phosphate; and the catalyst includes triphenylphosphine.

[0051] The molar ratio of the epoxy prepolymer containing phosphate groups to the polyether polyol in S1 is 2:1.

[0052] The molar ratio of the short-chain alkane group introducing agent in S2 to the polyether polyol is 0.05:1.

[0053] The molar ratio of the chain extender to the polyether polyol in S2 is 0.1:1.

[0054] The catalyst in S2 accounts for 0.3 wt% of the total amount of the reaction system.

[0055] S2 The polyether polyol includes polypropylene glycol; the short-chain alkane group introducing agent includes n-propanol; the chain extender includes a diamine; and the catalyst includes dibutyltin dilaurate.

[0056] The mass ratio of the neutralizer to the copolymer in S3 is 0.5:1.

[0057] The mass ratio of deionized water to copolymer in S3 is 8:1.

[0058] The neutralizing agent in S3 includes dimethylethanolamine.

[0059] Example 3 Preparation of waterborne epoxy-polyether copolymer resin:

[0060] S1. Prepare an epoxy prepolymer containing a phosphate group: Mix a bisphenol A epoxy resin and an epoxy resin reactive diluent. Add a phosphating agent and stir until uniform. Add a catalyst and stir again until uniform. React at 100-120°C for 2-3 hours to obtain an epoxy prepolymer containing a phosphate group.

[0061] S2. Introducing polyether segments and short-chain alkane groups: Mix the phosphate-containing epoxy prepolymer with the polyether polyol. Add a short-chain alkane group-introducing agent and a chain extender, and stir evenly. Add a catalyst and stir again. React at 80-100°C for 1-2 hours to obtain a copolymer containing polyether segments and short-chain alkane groups.

[0062] S3. Water-Based Emulsion: Mix the copolymer containing polyether segments and short-chain alkane groups with a neutralizer and neutralize to a neutral or slightly alkaline state. Slowly add deionized water while stirring at high speed to emulsify the mixture. Continue stirring until a stable aqueous emulsion is formed.

[0063] The molar ratio of the epoxy resin to the diluent in S1 is 2:1.

[0064] The molar ratio of the phosphating agent to the epoxy resin in S1 is 0.1:1.

[0065] The amount of catalyst used in S1 is 0.7 wt % of the epoxy resin.

[0066] The diluent in S1 includes butyl glycidyl ether; the phosphating agent includes triethyl phosphate; and the catalyst includes triphenylphosphine.

[0067] The molar ratio of the epoxy prepolymer containing phosphate groups to the polyether polyol in S1 is 2:1.

[0068] The molar ratio of the short-chain alkane group introducing agent in S2 to the polyether polyol is 0.05:1.

[0069] The molar ratio of the chain extender to the polyether polyol in S2 is 0.1:1.

[0070] The catalyst in S2 accounts for 0.2 wt% of the total amount of the reaction system.

[0071] S2 The polyether polyol includes polypropylene glycol; the short-chain alkane group introducing agent includes n-propanol; the chain extender includes a diamine; and the catalyst includes dibutyltin dilaurate.

[0072] The mass ratio of the neutralizer to the copolymer in S3 is 0.3:1.

[0073] The mass ratio of deionized water to copolymer in S3 is 6:1.

[0074] The neutralizing agent in S3 includes dimethylethanolamine.

[0075] Comparative Example 1 Preparation of waterborne epoxy-polyether copolymer resin (without introduction of phosphate groups):

[0076] S1, taking bisphenol A epoxy resin and epoxy resin reactive diluent and mixing;

[0077] S2. Introducing polyether segments and short-chain alkane groups: Mix the phosphate-containing epoxy prepolymer with the polyether polyol. Add a short-chain alkane group-introducing agent and a chain extender, and stir evenly. Add a catalyst and stir again. React at 80-100°C for 1-2 hours to obtain a copolymer containing polyether segments and short-chain alkane groups.

[0078] S3. Water-Based Emulsion: Mix the copolymer containing polyether segments and short-chain alkane groups with a neutralizer and neutralize to a neutral or slightly alkaline state. Slowly add deionized water while stirring at high speed to emulsify the mixture. Continue stirring until a stable aqueous emulsion is formed.

[0079] The molar ratio of the epoxy resin to the diluent in S1 is 2:1.

[0080] The diluent in S1 includes butyl glycidyl ether.

[0081] The molar ratio of the epoxy prepolymer containing phosphate groups to the polyether polyol in S1 is 2:1.

[0082] The molar ratio of the short-chain alkane group introducing agent in S2 to the polyether polyol is 0.05:1.

[0083] The molar ratio of the chain extender to the polyether polyol in S2 is 0.1:1.

[0084] The catalyst in S2 accounts for 0.2 wt% of the total amount of the reaction system.

[0085] S2 The polyether polyol includes polypropylene glycol; the short-chain alkane group introducing agent includes n-propanol; the chain extender includes a diamine; and the catalyst includes dibutyltin dilaurate.

[0086] The mass ratio of the neutralizer to the copolymer in S3 is 0.3:1.

[0087] The mass ratio of deionized water to copolymer in S3 is 6:1.

[0088] The neutralizing agent in S3 includes dimethylethanolamine.

[0089] Comparative Example 2 Preparation of waterborne epoxy-polyether copolymer resin (without introduction of polyether segment):

[0090] S1. Prepare an epoxy prepolymer containing a phosphate group: Mix a bisphenol A epoxy resin and an epoxy resin reactive diluent. Add a phosphating agent and stir until uniform. Add a catalyst and stir again until uniform. React at 100-120°C for 2-3 hours to obtain an epoxy prepolymer containing a phosphate group.

[0091] S2. Introducing polyether segments and short-chain alkane groups: Add a short-chain alkane group-introducing agent and a chain extender to the phosphate-containing epoxy prepolymer and stir evenly. Add a catalyst and stir again. React at 80-100°C for 1-2 hours to obtain a copolymer containing short-chain alkane groups.

[0092] S3. Water-based emulsion: Mix the copolymer with a neutralizing agent and neutralize to a neutral or slightly alkaline state. Slowly add deionized water while stirring at high speed to emulsify the mixture. Continue stirring until a stable aqueous emulsion is formed.

[0093] The molar ratio of the epoxy resin to the diluent in S1 is 2:1.

[0094] The molar ratio of the phosphating agent to the epoxy resin in S1 is 0.1:1.

[0095] The amount of catalyst used in S1 is 0.7 wt % of the epoxy resin.

[0096] The diluent in S1 includes butyl glycidyl ether; the phosphating agent includes triethyl phosphate; and the catalyst includes triphenylphosphine.

[0097] The molar ratio of the epoxy prepolymer containing phosphate groups to the short-chain alkane group introducing agent in S1 is 2:0.05.

[0098] The molar ratio of the chain extender in S2 to the short-chain alkane group introducing agent is 0.1:0.05.

[0099] The catalyst in S2 accounts for 0.2 wt% of the total amount of the reaction system.

[0100] S2 The short-chain alkane group introducing agent includes n-propanol; the chain extender includes a diamine; and the catalyst includes dibutyltin dilaurate.

[0101] The mass ratio of the neutralizer to the copolymer in S3 is 0.3:1.

[0102] The mass ratio of deionized water to copolymer in S3 is 6:1.

[0103] The neutralizing agent in S3 includes dimethylethanolamine.

[0104] Comparative Example 3 Preparation of waterborne epoxy-polyether copolymer resin (without introduction of tempered alkane groups):

[0105] S1. Prepare an epoxy prepolymer containing a phosphate group: Mix a bisphenol A epoxy resin and an epoxy resin reactive diluent. Add a phosphating agent and stir until uniform. Add a catalyst and stir again until uniform. React at 100-120°C for 2-3 hours to obtain an epoxy prepolymer containing a phosphate group.

[0106] S2. Introducing polyether segments and short-chain alkane groups: Mix the phosphate-containing epoxy prepolymer with the polyether polyol. Add a chain extender and stir until uniform. Add a catalyst and stir again until uniform. React at 80-100°C for 1-2 hours to obtain a copolymer containing polyether segments and short-chain alkane groups.

[0107] S3. Water-Based Emulsion: Mix the copolymer containing polyether segments and short-chain alkane groups with a neutralizer and neutralize to a neutral or slightly alkaline state. Slowly add deionized water while stirring at high speed to emulsify the mixture. Continue stirring until a stable aqueous emulsion is formed.

[0108] The molar ratio of the epoxy resin to the diluent in S1 is 2:1.

[0109] The molar ratio of the phosphating agent to the epoxy resin in S1 is 0.1:1.

[0110] The amount of catalyst used in S1 is 0.7 wt % of the epoxy resin.

[0111] The diluent in S1 includes butyl glycidyl ether; the phosphating agent includes triethyl phosphate; and the catalyst includes triphenylphosphine.

[0112] The molar ratio of the epoxy prepolymer containing phosphate groups to the polyether polyol in S1 is 2:1.

[0113] The molar ratio of the chain extender to the polyether polyol in S2 is 0.1:1.

[0114] The catalyst in S2 accounts for 0.2 wt% of the total amount of the reaction system.

[0115] The polyether polyol in S2 includes polypropylene glycol; the chain extender includes a diamine; and the catalyst includes dibutyltin dilaurate.

[0116] The mass ratio of the neutralizer to the copolymer in S3 is 0.3:1.

[0117] The mass ratio of deionized water to copolymer in S3 is 6:1.

[0118] The neutralizing agent in S3 includes dimethylethanolamine.

[0119] Performance testing:

[0120] The samples prepared according to the preparation methods of the above examples and comparative examples were subjected to performance tests:

[0121] Coating preparation:

[0122] Sample water-based epoxy-polyether copolymer resin: 50 parts

[0123] Deionized water: 20 parts

[0124] Defoamer BYK-028 (BYK Chemie GmbH): 0.5 parts

[0125] Leveling agent BYK-333 (BYK Chemie GmbH): 0.5 parts

[0126] Anti-rust pigment zinc phosphate: 5 parts

[0127] Thickener hydroxyethyl cellulose: 2 parts

[0128] Curing agent water-based polyamide curing agent: 3 parts

[0129] Preparation: Combine water-based epoxy-polyether copolymer resin with deionized water and stir thoroughly. Add defoamer, leveling agent, and anti-rust pigment sequentially, stirring continuously until uniform. Add thickener to adjust the coating viscosity. Add curing agent before use and stir thoroughly.

[0130] Coating: Prepare the metal substrate to ensure it is clean, dry, and free of oil, dirt, and rust. Use a spray gun to evenly apply the prepared water-based coating to the metal substrate. Curing should ensure the coating is completely dry.

[0131] Corrosion resistance testing: Conducted in accordance with the salt spray resistance test method specified in HG / T 4759-2014. Coated metal panels are placed in a salt spray chamber, set at a specific temperature and salt spray concentration, and observed for a specified period of time. The panel's corrosion severity after the salt spray test is assessed, using the protection rating (Rp) in accordance with ISO 10289 to describe the coating's ability to protect the base metal from corrosion.

[0132] Other performance tests: Other properties of the coating, such as drying time, hardness, adhesion, etc., are tested in accordance with HG / T 4759-2014 standard.

[0133] The performance test data is shown in Table 1:

[0134] Table 1 Performance test data of examples and comparative examples

[0135]

[0136] From the performance test data in Table 1, it can be seen that the introduction of phosphate groups can indeed improve the adhesion level of the coating prepared by the resin alone, while the effects of the other two groups in this regard are not significant. In terms of corrosion resistance, the contribution of the phosphate group alone is obviously relatively large, but when the phosphate group and the other two introduced groups exist at the same time, the corrosion resistance is greatly improved. This shows that the presence of several groups is not effective alone, but is affected by each other, resulting in a synergistic effect, thereby improving the performance of the coating prepared by the resin, especially in terms of corrosion resistance.

[0137] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A water-based epoxy-polyether copolymer resin capable of improving the corrosion resistance of a coating, characterized in that: The waterborne epoxy-polyether copolymer resin includes a dispersion prepared by the following steps: first synthesizing an epoxy prepolymer containing a phosphate group, then introducing a polyether segment and a short-chain alkane group, and finally neutralizing and dispersing; the introduction agent of the short-chain alkane group includes n-propanol.

2. A method for preparing a water-based epoxy-polyether copolymer resin capable of improving the corrosion resistance of a coating as claimed in claim 1, characterized in that: The following steps are involved: S1. Preparing an epoxy prepolymer containing a phosphate group: reacting an epoxy resin with a diluent, a phosphatizing agent, and a catalyst to obtain an epoxy prepolymer containing a phosphate group; S2. Introducing polyether segments and short-chain alkane groups: The obtained prepolymer is mixed with a polyether polyol, a short-chain alkane group introducing agent, a chain extender, and a catalyst to react to obtain a copolymer containing polyether segments and short-chain alkane groups; S3. Water-based: the obtained copolymer is mixed with a neutralizing agent and then deionized water is added for emulsification to form a water-based epoxy-polyether copolymer resin emulsion.

3. The method for preparing a water-based epoxy-polyether copolymer resin capable of improving the corrosion resistance of a coating according to claim 2, wherein: The molar ratio of the epoxy resin to the diluent in S1 is (2-3):1; the molar ratio of the phosphating agent to the epoxy resin in S1 is 0.1:1; and the amount of the catalyst in S1 is 0.5-0.8 wt % of the epoxy resin.

4. The method for preparing a water-based epoxy-polyether copolymer resin capable of improving the corrosion resistance of a coating according to claim 2, wherein: The reaction temperature of S1 is 100-120°C and the reaction time is 2-3 hours. The specific operation of S1 is: mixing bisphenol A epoxy resin and epoxy resin active diluent; adding phosphating agent and stirring evenly; adding catalyst and stirring evenly again; reacting at 100-120°C for 2-3 hours to obtain an epoxy prepolymer containing phosphate groups.

5. The method for preparing a water-based epoxy-polyether copolymer resin capable of improving the corrosion resistance of a coating according to claim 2, wherein: The diluent in S1 includes butyl glycidyl ether; the phosphating agent includes triethyl phosphate; and the catalyst includes triphenylphosphine.

6. The method for preparing a water-based epoxy-polyether copolymer resin capable of improving the corrosion resistance of a coating according to claim 2, wherein: The molar ratio of the epoxy prepolymer containing phosphate groups in S1 to the polyether polyol is 2:1; the molar ratio of the short-chain alkane group introducing agent in S2 to the polyether polyol is 0.05:1; the molar ratio of the chain extender in S2 to the polyether polyol is 0.1:1; the catalyst in S2 accounts for 0.1-0.3 wt% of the total amount of the reaction system.

7. The method for preparing a water-based epoxy-polyether copolymer resin capable of improving the corrosion resistance of a coating according to claim 2, wherein: The reaction described in S2 has a reaction temperature of 80-100°C and a reaction time of 1-2 hours. The specific operation of S2 is: mixing the epoxy prepolymer containing phosphate groups with the polyether polyol; adding a short-chain alkane group introduction agent and a chain extender, and stirring evenly; adding a catalyst and stirring evenly again; reacting at 80-100°C for 1-2 hours to obtain a copolymer containing polyether segments and short-chain alkane groups.

8. The method for preparing a water-based epoxy-polyether copolymer resin capable of improving the corrosion resistance of a coating according to claim 2, wherein: S2 The polyether polyol includes polypropylene glycol; the short-chain alkane group introducing agent includes n-propanol; the chain extender includes a diamine; and the catalyst includes dibutyltin dilaurate.

9. The method for preparing a water-based epoxy-polyether copolymer resin capable of improving the corrosion resistance of a coating according to claim 2, wherein: The mass ratio of the neutralizer to the copolymer in S3 is (0.1-0.5):1; the mass ratio of the deionized water to the copolymer in S3 is (5-8):

1.

10. The method for preparing a water-based epoxy-polyether copolymer resin capable of improving the corrosion resistance of a coating according to claim 2, characterized in that: The neutralizing agent in S3 includes dimethylethanolamine; the specific operation of S3 is: mixing the copolymer containing polyether segments and short-chain alkane groups with the neutralizing agent, neutralizing to neutral or slightly alkaline; slowly adding deionized water under high-speed stirring for emulsification; and continuing stirring until a stable aqueous emulsion is formed.

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