Modified polyether amine waterborne epoxy curing agent as well as preparation method and application thereof

Abstract

The invention provides a modified polyether amine waterborne epoxy curing agent as well as a preparation method and application thereof, and belongs to the technical field of waterborne epoxy coatings. The preparation method comprises the following steps: mixing polyether amine, bisphenol A epoxy resin and polyether alcohol diglycidyl ether, and carrying out addition-chain extension reaction to obtain an addition product; mixing the addition product with a monoepoxy compound, and carrying out an end-capping reaction to obtain an end-capped product; and mixing the end-capped product with water, and dispersing to obtain the modified polyether amine waterborne epoxy curing agent. Compared with a nonionic water-based epoxy curing agent obtained by modifying aliphatic polyamine, the modified polyether amine water-based epoxy curing agent prepared by the preparation method disclosed by the invention can greatly improve the weather resistance of a water-based epoxy coating, and also can improve the mechanical and physical properties of the epoxy coating, especially the mechanical strength and toughness.

Description

Technical Field

[0001] The invention relates to the technical field of waterborne epoxy coatings, and in particular to a modified polyetheramine waterborne epoxy curing agent and a preparation method and application thereof. Background Art

[0002] Epoxy coating is a two-component coating composed of epoxy resin and epoxy curing agent. Epoxy resin itself is a thermoplastic resin. Curing agent needs to be added to make the epoxy groups in the molecule react and open the ring, thereby forming a dense cross-linked network structure and obtaining excellent application performance. As society puts forward higher and higher requirements for environmental protection and human health, solvent-based epoxy system coatings are gradually replaced by solvent-free epoxy system coatings and water-based epoxy coatings. Solvent-free epoxy system coatings still add some active diluents such as butyl glycidyl ether during use, which makes the coating material have a strong odor and toxicity, affecting human health. Water-based epoxy coatings have a low VOC content and can reach zero VOC, which meets the current environmental protection needs and is therefore valued.

[0003] Commonly used waterborne epoxy curing agent products are mainly products modified with aliphatic polyamines, which are divided into ionic and non-ionic waterborne epoxy curing agents. Among them, ionic waterborne epoxy resin curing agents are made by modifying aliphatic polyamines and adding organic acids such as acetic acid to react with polyamines to form salts. Non-ionic waterborne epoxy curing agents occupy the main market of waterborne epoxy curing agents. By introducing hydrophilic groups, the water solubility of the curing agent is increased, so there is no need to add organic acid neutralizers, which has better use value. Non-ionic waterborne epoxy curing agents mainly chemically modify traditional aliphatic polyamines to obtain epoxy waterborne curing agent products. In the process of film formation with epoxy resin, the application period is short, the product has poor weather resistance, and the mechanical properties are average. In order to solve the shortcomings of aliphatic polyamine modification, waterborne epoxy curing agents with modified alicyclic amines have appeared on the market, which have a certain improvement in the weather resistance and mechanical properties of the product, but the weather resistance and mechanical properties are not up to the level of oily epoxy curing agents, so it is impossible to replace oily epoxy curing agents with waterborne epoxy curing agents.

[0004] Polyetheramine epoxy resin curing agent is an oily curing agent used in epoxy resin systems, which usually reacts with epoxy resin to form a high-strength, heat-resistant and chemical-resistant solid material. Polyetheramine epoxy resin curing agent is a specific type of epoxy resin curing agent. Its advantages in epoxy resin include: 1) fast curing. Polyetheramine epoxy resin curing agent can react with epoxy resin in a shorter time to form a strong polymer network structure; 2) chemical resistance. The cured polyetheramine epoxy resin has good chemical corrosion resistance and is suitable for applications requiring corrosion resistance; 3) strength and toughness. The epoxy resin cured with polyetheramine has high mechanical strength and toughness, which is suitable for engineering materials requiring high performance. However, the existing polyetheramine epoxy resin curing agent is an oily curing agent, which can only be used for oily epoxy resins, and cannot be used in water-based epoxy resins, and cannot improve the weather resistance and mechanical properties of water-based epoxy resins. Summary of the invention

[0005] The object of the present invention is to provide a modified polyetheramine waterborne epoxy curing agent and a preparation method and application thereof. The modified polyetheramine waterborne epoxy curing agent can improve the weather resistance and mechanical and physical properties of waterborne epoxy coatings.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing a modified polyetheramine waterborne epoxy curing agent, comprising the following steps:

[0008] The polyetheramine, bisphenol A epoxy resin and polyether alcohol diglycidyl ether are mixed to carry out addition-chain extension reaction to obtain an addition product;

[0009] The addition product is mixed with a monoepoxide compound and subjected to a capping reaction to obtain a capped product;

[0010] The end-capped product is mixed with water and dispersed to obtain a modified polyetheramine water-based epoxy curing agent.

[0011] Preferably, the polyetheramine includes one or both of polyetheramine D230 and polyetheramine D400.

[0012] Preferably, the bisphenol A type epoxy resin includes one or both of E51 and E44; the polyether alcohol diglycidyl ether includes one or more of polypropylene glycol diglycidyl ether and polyethylene glycol diglycidyl ether.

[0013] Preferably, the molar ratio of the polyetheramine to the mixture of bisphenol A epoxy resin and polyether alcohol diglycidyl ether is 1.8 to 2.0:1.

[0014] Preferably, the temperature of the addition-chain extension reaction is 55-80° C., and the reaction time is 3-6 hours.

[0015] Preferably, the monoepoxide comprises one or more of C12-C14 alkyl glycidyl ether, n-butyl glycidyl ether, phenyl glycidyl ether, o-cresyl glycidyl ether and benzyl glycidyl ether; and the molar ratio of the monoepoxide to the mixture of bisphenol A epoxy resin and polyether alcohol diglycidyl ether is 0.7 to 1.2:1.

[0016] Preferably, the end-capping reaction is carried out at a temperature of 55 to 80° C. and for a time of 3 to 6 hours.

[0017] Preferably, the solid content of the modified polyetheramine waterborne epoxy curing agent is 50-60wt%.

[0018] The present invention provides a modified polyetheramine waterborne epoxy curing agent prepared by the preparation method described in the above technical scheme.

[0019] The present invention provides application of the modified polyetheramine waterborne epoxy curing agent described in the above technical solution in waterborne epoxy coatings.

[0020] The present invention provides a method for preparing a modified polyetheramine waterborne epoxy curing agent. The polyetheramine itself has the ability to improve weather resistance and mechanical properties. The present invention performs water-based modification on the polyetheramine, and the main structure of the polyetheramine is retained, thereby improving the weather resistance and mechanical properties of waterborne epoxy coatings. The present invention first uses a mixture of bisphenol A epoxy resin and polyether alcohol diglycidyl ether for addition-chain extension, and then uses monoepoxy end-capping. The bisphenol A epoxy resin and polyether alcohol diglycidyl ether mixture used make the curing agent chain-shaped to prevent cross-linking. The curing agent forms a chain with more hydroxyl groups, thereby greatly increasing water solubility, which is beneficial to its application in waterborne epoxy coatings. Compared with the non-ionic waterborne epoxy curing agent obtained by modifying aliphatic polyamines, the modified polyetheramine waterborne epoxy curing agent prepared by the present invention can greatly improve the weather resistance of waterborne epoxy coatings, and at the same time can improve the mechanical and physical properties of epoxy coatings, especially mechanical strength and toughness. DETAILED DESCRIPTION

[0021] The present invention provides a method for preparing a modified polyetheramine waterborne epoxy curing agent, comprising the following steps:

[0022] The polyetheramine, bisphenol A epoxy resin and polyether alcohol diglycidyl ether are mixed to carry out addition-chain extension reaction to obtain an addition product;

[0023] The addition product is mixed with a monoepoxide compound and subjected to a capping reaction to obtain a capped product;

[0024] The end-capped product is mixed with water and dispersed to obtain a modified polyetheramine water-based epoxy curing agent.

[0025] In the present invention, unless otherwise specified, the raw materials or reagents used are commercially available products well known in the art.

[0026] The invention mixes polyetheramine, bisphenol A epoxy resin and polyether alcohol diglycidyl ether, and performs addition-chain extension reaction to obtain an addition product.

[0027] In the present invention, the polyetheramine preferably includes one or both of polyetheramine D230 and polyetheramine D400. When the polyetheramine is the above two types, the present invention has no special limitation on the ratio of the two, and any ratio is acceptable.

[0028] In the present invention, the bisphenol A epoxy resin preferably includes one or two of E51 and E44; when the bisphenol A epoxy resin is the above two types, the present invention has no special limitation on the ratio of the two, and any ratio is acceptable.

[0029] In the present invention, the polyether alcohol diglycidyl ether includes one or more of polypropylene glycol diglycidyl ether and polyethylene glycol diglycidyl ether, preferably polyethylene glycol diglycidyl ether and polypropylene glycol diglycidyl ether. When the polyether alcohol diglycidyl ether is the above two types, the present invention has no special restrictions on the ratio of different types of polyether alcohol diglycidyl ethers, and any ratio is acceptable.

[0030] In the present invention, the molar ratio of the polyetheramine to the mixture of bisphenol A epoxy resin and polyether alcohol diglycidyl ether is preferably 1.8 to 2.0:1, more preferably 1.9 to 2.0:1.

[0031] The present invention has no particular limitation on the ratio of the bisphenol A epoxy resin to the polyether alcohol diglycidyl ether, and any ratio is acceptable, more preferably 6 to 8:2 to 4, and even more preferably 7:3.

[0032] The present invention preferably adds a mixture of bisphenol A epoxy resin and polyether alcohol diglycidyl ether to the polyether amine to carry out an addition-chain extension reaction; the dropping time of the mixture of bisphenol A epoxy resin and polyether alcohol diglycidyl ether is preferably 1 to 3 hours, more preferably 1 to 2 hours.

[0033] In the present invention, the temperature of the addition-chain extension reaction is preferably 55-80° C., more preferably 60-70° C., further preferably 65° C., and the reaction time is preferably 3-6 h, more preferably 4-5 h.

[0034] After the addition-chain extension reaction is completed, the present invention does not require post-treatment, and directly mixes the obtained addition product with the monoepoxide compound to perform a capping reaction to obtain a capped product.

[0035] In the present invention, the monoepoxy compound preferably includes one or more of C12-C14 alkyl glycidyl ether, n-butyl glycidyl ether, phenyl glycidyl ether, o-cresyl glycidyl ether and benzyl glycidyl ether, more preferably phenyl glycidyl ether and / or benzyl glycidyl ether. The present invention has no particular limitation on the source of the monoepoxy compound, and any commercially available product known in the art may be used.

[0036] In the present invention, the molar ratio of the monoepoxy compound to the mixture of bisphenol A epoxy resin and polyether alcohol diglycidyl ether is preferably 0.7 to 1.2:1, more preferably 0.75 to 1.1:1, and further preferably 0.8 to 1.0:1.

[0037] In the present invention, a monoepoxy compound is preferably added dropwise to the addition product to carry out a capping reaction; the monoepoxy compound is preferably added dropwise within 1 to 3 hours, more preferably within 2 hours.

[0038] In the present invention, the temperature of the end-capping reaction is preferably 55 to 80° C., more preferably 60 to 75° C., further preferably 65 to 70° C., and the time is 3 to 6 hours, more preferably 4 to 5 hours.

[0039] After the end-capping reaction is completed, the present invention preferably adds water to the reaction solution for dispersion to obtain a modified polyetheramine water-based epoxy curing agent (non-ionic).

[0040] The amount of water used in the present invention can reach the required solid content; the present invention has no special limitation on the dispersion, and the dispersion can be uniformly carried out according to the process well known in the art.

[0041] In the present invention, the solid content of the modified polyetheramine waterborne epoxy curing agent is preferably 50 to 60 wt %, more preferably 52 to 55 wt %.

[0042] The present invention provides a modified polyetheramine waterborne epoxy curing agent prepared by the preparation method described in the above technical scheme.

[0043] The present invention provides the use of the modified polyetheramine waterborne epoxy curing agent described in the above technical solution in waterborne epoxy coatings. The present invention has no special limitation on the method of the application, and the application can be carried out according to methods well known in the art.

[0044] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0045] Example 1

[0046] According to a molar ratio of 7:3, 54.9 g of epoxy resin E51 and 32.4 g of polyethylene glycol diglycidyl ether (epoxy value 0.37) were weighed and mixed uniformly to obtain a mixture;

[0047] 92 g of polyetheramine D230 was added to a 1000 mL four-necked flask, and the temperature was raised to 65 ° C. After the temperature was constant, the epoxy resin E51 and the polyethylene glycol diglycidyl ether mixture were added dropwise, the molar ratio of the polyetheramine to the epoxy resin E51 and the polyethylene glycol diglycidyl ether mixture was 2.0: 1, the dropping time was controlled for 2 h, the dropping was completed, and the reaction was kept warm for 4 h. After the insulation was completed, 32.8 g of benzyl glycidyl ether was added dropwise at 65 ° C., the molar ratio of benzyl glycidyl ether to the epoxy resin E51 and the polyethylene glycol diglycidyl ether mixture was 0.75: 1, the dropping time was controlled for 2 h, the dropping was completed, and the reaction was kept warm for 4 h at 65 ° C. After the reaction was completed, 173.5 g of deionized water was added dropwise to the reaction solution. After the dropping was completed, it was stirred for 3 h to mix evenly to obtain a water-based epoxy curing agent 1 with a solid content of 55 wt%.

[0048] Example 2

[0049] According to a molar ratio of 6:4, 54.5 g of epoxy resin E44 and 51.2 g of polypropylene glycol diglycidyl ether (epoxy value 0.31) were weighed and mixed uniformly to obtain a mixture;

[0050] Add 160g of polyetheramine D400 to a 1000mL four-necked flask, heat to 60°C, and after the temperature is constant, add a mixture of epoxy resin E44 and polypropylene glycol diglycidyl ether dropwise, the molar ratio of polyetheramine to the mixture of epoxy resin E44 and polypropylene glycol diglycidyl ether is 2.0:1, control the dropping time for 3h, add the addition dropwise, and keep the reaction warm for 3h. After the insulation is completed, add 24g of phenyl glycidyl ether at 60°C, the molar ratio of phenyl glycidyl ether to the mixture of epoxy resin E44 and polypropylene glycol diglycidyl ether is 0.8:1, control the addition time for 3h, add the addition dropwise, and keep the reaction warm for 5h at 60°C. After the reaction is completed, add 289.7g of deionized water to the reaction solution. After the addition is completed, stir for 3h to mix evenly to obtain a water-based epoxy curing agent 2 with a solid content of 50wt%.

[0051] Example 3

[0052] According to a molar ratio of 8:2, 62.7 g of epoxy resin E51 and 21.6 g of polyethylene glycol diglycidyl ether (epoxy value 0.37) were weighed and mixed uniformly to obtain a mixture;

[0053] 82.8 g of polyetheramine D230 was added to a 1000 mL four-necked flask, and the temperature was raised to 70° C. After the temperature was constant, a mixture of epoxy resin E51 and polyethylene glycol diglycidyl ether was added dropwise, the molar ratio of polyetheramine to the mixture of epoxy resin E51 and polyethylene glycol diglycidyl ether was 1.8:1, the dropping time was controlled for 1 h, the dropping was completed, and the reaction was kept warm for 6 h. After the insulation was completed, 28.6 g of n-butyl glycidyl ether was added dropwise at 70° C., the molar ratio of n-butyl glycidyl ether to the mixture of epoxy resin E51 and polyethylene glycol diglycidyl ether was 1.1:1, the dropping time was controlled for 1 h, the dropping was completed, and the reaction was kept warm for 3 h at 70° C. After the reaction was completed, 180.6 g of deionized water was added dropwise to the reaction solution. After the dropping was completed, the mixture was stirred for 3 h to obtain a water-based epoxy curing agent 3 with a solid content of 52 wt%.

[0054] Comparative Example 1

[0055] According to a molar ratio of 7:3, 54.9 g of epoxy resin E51 and 32.4 g of polyethylene glycol diglycidyl ether (epoxy value 0.37) were weighed and mixed uniformly to obtain a mixture;

[0056] Add 61.3g of triethylenetetramine to a 500mL four-necked flask, heat to 65°C, and after the temperature is constant, add a mixture of epoxy resin E51 and polyethylene glycol diglycidyl ether dropwise, control the dropping time for 2h, complete the dropping, and keep warm for 4h. After the insulation is completed, control the vacuum degree to 200pa, distill the unreacted triethylenetetramine until no liquid flows out, and the distillation ends in seconds to obtain 2.9g of triethylenetetramine. Remove the vacuum, cool to 65°C, add 32.8g of benzyl glycidyl ether dropwise, control the dropping time for 2h, complete the dropping, and keep warm for 4h. After the reaction is completed, add 146g of deionized water to the reaction solution. After the addition is completed, stir for 3h to mix evenly to obtain a comparative water-based epoxy curing agent 1 with a solid content of 55wt%.

[0057] Comparative Example 2

[0058] According to a molar ratio of 6:4, 54.5 g of epoxy resin E44 and 51.2 g of polypropylene glycol diglycidyl ether (epoxy value 0.31) were weighed and mixed uniformly to obtain a mixture;

[0059] Add 39.1g of diethylenetriamine to a 500mL four-necked flask, raise the temperature to 60°C, and after the temperature is constant, add a mixture of epoxy resin E44 and polypropylene glycol diglycidyl ether dropwise, control the dropping time for 3h, complete the dropping, and keep warm for 3h. After the insulation is completed, control the vacuum degree to 100pa, distill the unreacted diethylenetriamine until no liquid flows out, complete the distillation, remove the vacuum, cool to 60°C, add 24g of phenyl glycidyl ether dropwise, control the dropping time for 3h, complete the dropping, and keep warm for 5h. After the reaction is completed, add 168.8g of deionized water to the reaction solution. After the dropping is completed, stir for 3h to mix evenly to obtain a comparative water-based epoxy curing agent 2 with a solid content of 50wt%.

[0060] Comparative Example 3

[0061] According to a molar ratio of 8:2, 62.7 g of epoxy resin E51 and 21.6 g of polyethylene glycol diglycidyl ether (epoxy value 0.37) were weighed and mixed uniformly to obtain a mixture;

[0062] Add 27.6g of ethylenediamine to a 500mL four-necked flask, heat to 75°C, and after the temperature is constant, add a mixture of epoxy resin E51 and polyethylene glycol diglycidyl ether dropwise, control the dropping time for 1h, complete the dropping, and keep warm for 6h. After the insulation is completed, control the vacuum degree to 300pa, distill the unreacted ethylenediamine until no liquid flows out, and the distillation is completed to obtain 3.6g of ethylenediamine. Remove the vacuum, cool to 75°C, add 28.6g of n-butyl glycidyl ether dropwise, control the dropping time for 1h, complete the dropping, and keep warm for 3h. After the reaction is completed, add 126.4g of deionized water to the reaction solution. After the addition is completed, stir for 3h to mix evenly to obtain a water-comparative epoxy curing agent 3 with a solid content of 52wt%.

[0063] Performance Testing

[0064] The curing agents obtained in the above Examples 1 to 3 and Comparative Examples 1 to 3 were subjected to parallel comparative experimental tests with homemade waterborne epoxy medium grey topcoat. The formula of the waterborne epoxy medium grey topcoat is shown in Table 1:

[0065] Table 1 Self-made water-based epoxy medium grey topcoat (component A)

[0066]

[0067]

[0068] The active hydrogen equivalent details of the waterborne epoxy curing agent of each embodiment and comparative example and the formulation ratio of the application test are shown in Table 2:

[0069] Table 2 Parameters of waterborne epoxy curing agent (component B) and its ratio with component A

[0070]

[0071] The parallel comparison performance test is shown in Table 3:

[0072] Table 3 Performance of the waterborne epoxy curing agent of the embodiment and the comparative example respectively with the homemade waterborne epoxy medium gray topcoat

[0073]

[0074]

[0075] From the comparison in Table 3, it is found that the applicable period of Examples 1 to 3 and Comparative Examples 1 to 3 is 4 hours, which is no difference, basically meets the actual application requirements, and the construction window is relatively long. In terms of weather resistance, through the comparison of the artificial aging test, the time that Examples 1 to 3 can maintain without obvious powdering, gloss loss, cracking, discoloration, blistering, and peeling is 528 to 552 hours, while the time that Comparative Examples 1 to 3 can maintain without obvious powdering, gloss loss, cracking, discoloration, blistering, and peeling is 264 to 288 hours. By comparison, it is found that the Examples are significantly stronger in terms of weather resistance. As for the comparative example, the reason is analyzed from the perspective of the basic amine. The weather resistance of the polyetheramine itself has certain advantages over that of the fatty amine. After the respective modified water-based epoxy curing agents, the modified polyetheramine has enhanced hydrophilicity due to its ether bond, so the overall water solubility is stronger than that of the modified fatty amine. After mixing with the A component water-based epoxy emulsion, the mutual permeability is better and the cross-linking density is greater, which provides a strong guarantee for the improvement of weather resistance. Therefore, the overall weather resistance of the paint film prepared by the modified polyetheramine water-based epoxy curing agent used in the embodiment is stronger than that of the paint film prepared by the modified fatty amine used in the comparative example.

[0076] At the same time, the flexibility of the modified polyetheramine chain segment is higher than that of the modified fatty amine, and the overall flexibility is improved. Because of this, in terms of physical and mechanical properties, the flexibility of Examples 1 to 3 is 1 mm, while that of Comparative Examples 1 to 3 is 2 mm, indicating that the modified polyetheramine waterborne epoxy curing agent is stronger than the modified fatty amine waterborne epoxy curing agent in terms of flexibility; the adhesion of the pull-out method examines the bonding force between the paint film and the substrate, and the cohesion of the paint film itself. The better the toughness of the paint film, the more difficult it is to destroy the cohesion, and the higher the rigidity, the easier it is to destroy the cohesion. Actual tests also found that the pull-off adhesion of Examples 1 to 3 is significantly better than that of Comparative Examples 1 to 3, especially in Example 2, the proportion of polyetheramine is relatively large, and D400 is used, which has sufficient toughness and is less likely to cause cohesive failure. The measured value of 10.4 MPa is the most outstanding; the impact resistance is also related to the rigidity of the paint film after drying. The stronger the rigidity, the easier it is to produce network cracks. Conversely, the higher the flexibility, the better the impact resistance. Therefore, the impact resistance value of Examples 1 to 3 is 50 cm, which is better than the 40 cm measured in Comparative Examples 1 to 3 as a whole. Based on the high rigidity of the epoxy system itself, the advantage of 10 cm has already explained the problem; in terms of pencil hardness and cross-grid adhesion, there is no obvious difference between Examples 1 to 3 and Comparative Examples 1 to 3, and the performance is excellent. This is also an inherent advantage of the two-component water-based epoxy system, with high rigidity and hardness, and hydroxyl and epoxy groups provide sufficient substrate bonding.

[0077] In summary, the overall performance of the modified polyether amine waterborne epoxy curing agent is significantly better than that of the modified fatty amine waterborne epoxy curing agent. It is better compatible with the A component waterborne epoxy medium gray topcoat and has better performance, especially in terms of weather resistance, flexibility, pull-off adhesion and impact resistance.

[0078] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a modified polyetheramine waterborne epoxy curing agent, characterized in that: The following steps are involved: The polyetheramine, bisphenol A epoxy resin and polyether alcohol diglycidyl ether are mixed to carry out addition-chain extension reaction to obtain an addition product; The addition product is mixed with a monoepoxide compound and subjected to a capping reaction to obtain a capped product; The end-capped product is mixed with water and dispersed to obtain a modified polyetheramine water-based epoxy curing agent.

2. The preparation method according to claim 1, characterized in that: The polyetheramine includes one or both of polyetheramine D230 and polyetheramine D400.

3. The preparation method according to claim 1, characterized in that: The bisphenol A type epoxy resin includes one or two of E51 and E44; the polyether alcohol diglycidyl ether includes one or more of polypropylene glycol diglycidyl ether and polyethylene glycol diglycidyl ether.

4. The preparation method according to claim 1, 2 or 3, characterized in that: The molar ratio of the polyetheramine to the mixture of bisphenol A epoxy resin and polyether alcohol diglycidyl ether is 1.8-2.0:

1.

5. The preparation method according to claim 4, characterized in that: The temperature of the addition-chain extension reaction is 55-80° C., and the reaction time is 3-6 hours.

6. The preparation method according to claim 1, characterized in that: The monoepoxy compound includes one or more of C12-C14 alkyl glycidyl ether, n-butyl glycidyl ether, phenyl glycidyl ether, o-cresyl glycidyl ether and benzyl glycidyl ether; the molar ratio of the monoepoxy compound to the mixture of bisphenol A epoxy resin and polyether alcohol diglycidyl ether is 0.7-1.2:

1.

7. The preparation method according to claim 1 or 6, characterized in that: The temperature of the end-capping reaction is 55-80° C. and the time is 3-6 hours.

8. The preparation method according to claim 1, characterized in that: The solid content of the modified polyetheramine waterborne epoxy curing agent is 50-60wt%.

9. The modified polyetheramine waterborne epoxy curing agent prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the modified polyetheramine waterborne epoxy curing agent according to claim 9 in waterborne epoxy coatings.

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