Hydrogenated bisphenol A epoxy resin modified polyaspartic acid ester polyurea coating as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of polyaspartic acid ester polyurea, and discloses a hydrogenated bisphenol A epoxy resin modified polyaspartic acid ester polyurea coating as well as a preparation method and application thereof. The preparation method comprises the following steps: carrying out reaction on alicyclic primary diamine and maleate, then adding hydrogenated bisphenol A epoxy resin, and carrying out ring-opening reaction on an epoxy group to prepare modified polyaspartic acid ester; the preparation method comprises the following steps: reacting aliphatic or alicyclic isocyanate with polyether polyamine in a solvent to prepare a curing agent; and mixing the modified polyaspartic acid ester with a curing agent to prepare the polyurea coating. Due to introduction of hydrogenated bisphenol A epoxy resin and improvement of the crosslinking degree, the overall mechanical performance and heat resistance of the polyurea are obviously improved; meanwhile, the solvent resistance and the acid and alkali resistance are improved. The coating has excellent mechanical properties, corrosion resistance and weather resistance, and is expected to be used in outdoor coatings and metal surface protective coatings.

Description

Technical Field

[0001] The present invention belongs to the technical field of polyaspartic ester polyurea, and particularly relates to a hydrogenated bisphenol A epoxy resin modified polyaspartic ester polyurea coating, a preparation method thereof, and an application thereof. Background Art

[0002] A protective coating is usually coated on the surface of a device to protect the device from damage caused by factors such as cuts, chemical corrosion, ultraviolet rays, and water, and plays a crucial role in protecting the device and extending its service life. The two-component polyurea has excellent mechanical properties, heat resistance, chemical resistance, waterproof ability, and a short curing time, so it has attracted much attention from researchers. However, the rapid reaction between the primary amine and isocyanate in polyurea limits their application in some key technologies and coatings. Currently, commercial polyurea has developed from the first-generation aromatic polyurea to the third-generation polyaspartic polyurea. The polyaspartic ester molecule structure contains a secondary amine functional group, which has a steric hindrance effect, effectively shortening the gel time of polyurea, and overcoming the problem of construction difficulties related to the rapid curing of the first two generations of polyurea.

[0003] The polyaspartic ester polyurea coating has more advantages than polyurethane, epoxy resin, acrylate, and traditional polyurea protective solvent-based high-solid content coatings. In terms of performance, while having high hardness, they have a longer pot life. In addition, they also have excellent abrasion resistance, durability, flexibility, ultraviolet resistance, as well as excellent chemical resistance, heat resistance, and water resistance. More importantly, the polyaspartic ester resin has a low viscosity and good fluidity, so the polyaspartic ester coating can be produced at a high solid content (solid content ≥ 60 wt%), and can even be manufactured without solvents, and this property complies with VOC regulations.

[0004] The synthesis process of polyaspartic ester can achieve a completely solvent-free and catalyst-free green synthesis. By using the Michael addition reaction of double bonds and primary amines, the primary amine can be converted into secondary amine, greatly reducing the activity of amino groups, thereby extending the construction period; however, the technical difficulty in the synthesis of polyaspartic ester lies in the reduction of the primary amine content. As the reaction progresses, it takes a long time for the amino groups to be completely converted, which is not conducive to production and utilization. Summary of the Invention

[0005] In order to overcome the disadvantages and deficiencies existing in the prior art, the primary object of the present invention is to provide a preparation method for a hydrogenated bisphenol A epoxy resin modified polyaspartic ester polyurea coating.

[0006] Another object of the present invention is to provide a hydrogenated bisphenol A epoxy resin modified polyaspartic ester polyurea coating prepared by the above preparation method.

[0007] Another object of the present invention is to provide an application of the above-mentioned hydrogenated bisphenol A epoxy resin-modified polyaspartate polyurea coating.

[0008] The object of the present invention is achieved by the following technical solutions:

[0009] A preparation method of a hydrogenated bisphenol A epoxy resin-modified polyaspartate polyurea coating includes the following operating steps: reacting an alicyclic primary diamine with a maleate ester, and then adding a hydrogenated bisphenol A epoxy resin to obtain a modified polyaspartate by ring-opening reaction of epoxy groups, wherein the molar number of amino groups contained in the alicyclic primary diamine is the sum of the molar numbers of double bonds contained in the maleate ester and epoxy groups contained in the hydrogenated bisphenol A epoxy resin; reacting an aliphatic or alicyclic isocyanate with a polyether polyamine in a solvent to obtain a curing agent; mixing the modified polyaspartate and the curing agent to prepare a hydrogenated bisphenol A epoxy resin-modified polyaspartate polyurea coating.

[0010] The alicyclic primary diamine is one or a mixture of more than one of 4,4'-diaminodicyclohexylmethane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, isophorone diamine, and 1,3'-cyclohexanedimethanamine; the maleate ester is one or a mixture of more than one of dimethyl maleate, diethyl maleate, dipropyl maleate, dibutyl maleate, and diisobutyl maleate.

[0011] Preferably, the alicyclic primary diamine is 4,4'-diaminodicyclohexylmethane; the maleate ester is diethyl maleate; the molar ratio of 4,4'-diaminodicyclohexylmethane to diethyl maleate is 1:1.9 to 1:1.6; the dosage of the hydrogenated bisphenol A epoxy resin is 4 to 16% of the total amount of raw materials, and the total amount of raw materials refers to the sum of the masses of 4,4'-diaminodicyclohexylmethane, diethyl maleate, and hydrogenated bisphenol A epoxy resin.

[0012] The aliphatic or alicyclic isocyanate is one or a mixture of more than one of hexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate trimer; the polyether polyamine is one or a mixture of more than one of polyetheramine D230, polyetheramine D400, polyetheramine D2000, polyetheramine D4000, polyetheramine T403, and polyetheramine T5000.

[0013] Preferably, the alicyclic isocyanate is 4,4'-dicyclohexylmethane diisocyanate; the polyether polyamine is polyetheramine D2000 and polyetheramine T403, and the molar ratio of their dosages is 0.65:1 to 1.67:1; the dosage of polyetheramine T403 is 6-14% of the total amount of the curing agent main body, and the total amount of the curing agent main body refers to the sum of the masses of 4,4'-dicyclohexylmethane diisocyanate, polyetheramine D2000 and polyetheramine T403.

[0014] The solvent is one or a mixture of more of butyl acetate, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, 1,4-dioxane and propylene glycol methyl ether; preferably, the solvent is N,N-dimethylformamide.

[0015] The preparation method of the above-mentioned hydrogenated bisphenol A epoxy resin modified polyaspartic acid ester polyurea coating specifically comprises the following operation steps:

[0016] S1. Under an inert gas atmosphere, first put the alicyclic primary diamine into a three-necked flask, assemble the flask into an oil bath, and dropwise add the maleate into the flask while stirring, with the temperature of the flask always controlled below 60 °C; after the dropwise addition of the maleate is completed, raise the temperature to 60-100 °C and react for 10-16 h.

[0017] S2. Add hydrogenated bisphenol A epoxy resin, raise the temperature to 100-120 °C and stir and react for 10-16 h to obtain the modified polyaspartic acid ester.

[0018] S3. Under an inert gas atmosphere, add 4,4'-diisocyanatodicyclohexylmethane and a solvent into the three-necked flask, then add polyetheramine D2000 and stir at room temperature for 20 min, raise the temperature to 70-85 °C and stir and react for 2-3 h; after the reaction is completed, cool the flask to 10 °C with ice water.

[0019] S4. Dissolve polyetheramine T403 in N,N-dimethylformamide, add it to the flask cooled in step S3, keep reacting at 10 °C, and obtain the isocyanate prepolymer curing agent after the reaction is completed.

[0020] S5. Take the modified polyaspartic acid ester obtained in step S2 and the isocyanate prepolymer curing agent obtained in step S4 according to the molar ratio of functional groups NCO:NH = 1.05:1, stir and mix them, reduce the pressure to -0.09 to -0.1 MPa, heat to remove the solvent, and cure at 70-90 °C for 15-24 h to obtain the hydrogenated bisphenol A epoxy resin modified polyaspartic acid ester polyurea coating.

[0021] The reaction in step S1 is to raise the reaction temperature to 90 °C and react for 12 h.

[0022] The reaction described in step S2 is carried out at 105 °C for 12 h;

[0023] Before the polyetheramine D2000 described in step S3 is added, it is first stirred at 105 °C and under reduced pressure of -0.09 to -0.1 MPa for 2 h to fully remove moisture; the reaction is carried out at 80 °C for 2.5 h;

[0024] The reaction time described in step S4 is 15 min;

[0025] A hydrogenated bisphenol A epoxy resin modified polyaspartic acid ester polyurea coating prepared by the above preparation method.

[0026] The application of the above hydrogenated bisphenol A epoxy resin modified polyaspartic acid ester polyurea coating in the surface protection of metal materials.

[0027] The principle of the present invention is:

[0028] In the present invention, an excess of aliphatic or cycloaliphatic primary diamine is reacted with an alkylated maleate by a Michael addition reaction to obtain a resin, which can convert the primary amine into a secondary amine and reduce its reaction activity; by the ring-opening reaction of an epoxy group with a primary amine, hydrogenated bisphenol A epoxy resin is added to the resin obtained above to convert the excess primary amine into a secondary amine, obtaining a hydrogenated bisphenol A epoxy resin modified polyaspartic acid ester, improving the amino conversion rate and reducing the amino reaction activity; and the hydrogenated bisphenol A epoxy resin replaces the benzene ring in the traditional epoxy resin structure with a saturated six-membered ring, so it can overcome the defects of traditional epoxy resins being sensitive to ultraviolet light, easy to yellow, break, and powder, and at the same time it has a lower viscosity, which is convenient for pouring and filler infiltration, and also shows good weather resistance, chemical resistance, corona resistance, tracking resistance, has a high dielectric strength, and has good mechanical strength and toughness. Introducing hydrogenated bisphenol A epoxy resin into the synthesis reaction can comprehensively improve the mechanical properties, thermal stability, solvent resistance and corrosion resistance of the polyurea prepared therefrom; by mixing and reacting an organic cycloaliphatic isocyanate with a polyether polyamine, an isocyanate prepolymer curing agent is prepared, reducing the content of isocyanate groups, reducing the reaction activity of the curing agent, increasing the pot life of the coating, and extending the construction time.

[0029] The present invention has the following advantages and effects compared with the prior art:

[0030] The present invention provides a method for preparing polyaspartic ester polyurea. By using hydrogenated bisphenol A epoxy resin to modify polyaspartic ester, polyaspartic esters with different contents of hydrogenated bisphenol A epoxy resin are prepared. The introduction of hydrogenated bisphenol A epoxy resin and the improvement of the crosslinking degree significantly enhance the overall mechanical properties and heat resistance of the polyurea; at the same time, its solvent resistance and acid and alkali resistance are improved. This coating has excellent mechanical properties, corrosion resistance and weather resistance, and is expected to be used in outdoor coatings and metal surface protective coatings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the synthesis principle of modified polyaspartic ester.

[0032] Figure 2 It is a schematic diagram of the synthesis principle of isocyanate prepolymer curing agent.

[0033] Figure 3 It is the infrared spectrum of the synthesis raw materials and the synthesized modified polyaspartic ester in step S1 of Example 1.

[0034] Figure 4 It is the infrared spectrum of the polyurea coating film. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The following further illustrates the content of the present invention in conjunction with specific embodiments and the accompanying drawings, but should not be construed as a limitation to the present invention.

[0036] Example 1

[0037] S1: Weigh the raw materials according to the molar ratio of 4,4'-diaminodicyclohexylmethane (HMDA) to diethyl maleate (DEM) of 1:1.8; under an inert gas atmosphere, first put 16.32 g of 4,4'-diaminodicyclohexylmethane into a three-necked flask, and then slowly add 24.55 g of diethyl maleate to the flask through a constant pressure dropping funnel, while controlling the temperature below 60 °C; after the dropping is completed, raise the temperature to 90 °C and react for 12 h; then add 3.95 g of hydrogenated bisphenol A epoxy resin (DGEHBA), raise the temperature to 105 °C, and continue to react for 12 hours to obtain modified polyaspartic ester (PAE). The specific schematic diagram is as Figure 1 shown.

[0038] S2: Before use, polyetheramine D2000 was stirred at 105 °C under reduced pressure of -0.09 to -0.1 MPa for 2 h to fully remove moisture. Under an inert gas atmosphere, 3.33 g of 4,4'-diisocyanatodicyclohexylmethane (HMDI) was put into a three-necked flask, and 10 mL of N,N-dimethylformamide (DMF) was added. After quickly adding 3 g of polyetheramine D2000, it was stirred at room temperature for 20 min, then heated to 80 °C and reacted for 2.5 h. After the reaction was completed, the flask was cooled to 10 °C with ice water. 0.27 g of polyetheramine T403 was dissolved in 5 mL of DMF, and slowly added to the cooled three-necked flask. After continuing to stir at 10 °C for 15 min, an isocyanate prepolymer curing agent was obtained. The curing agent synthesized in this step was one portion. The specific schematic diagram is as shown in Figure 2 shown.

[0039] S3: 4.76 g of the modified polyaspartate synthesized in step S1 was weighed and stirred and mixed with one portion of the isocyanate prepolymer curing agent synthesized in step S2. After removing bubbles under reduced pressure and vacuum, it was poured into a polytetrafluoro mold and cured at 80 °C for 24 h to obtain a hydrogenated bisphenol A epoxy resin modified polyaspartate polyurea coating.

[0040] The preparation method steps of the polyurea coatings in Examples 2 - 7 were the same as those in Example 1, the difference being the different dosages of raw materials. The dosages of each raw material are shown in Table 1:

[0041] Table 1 Preparation raw material ratios of the polyurea coatings in Examples 1 - 7

[0042]

[0043] Comparative Example 1

[0044] S1: The raw materials were weighed according to the molar ratio of 4,4'-diaminodicyclohexylmethane (HMDA) to diethyl maleate (DEM) of 1:2. Under an inert gas atmosphere, first 16.32 g of 4,4'-diaminodicyclohexylmethane was put into a three-necked flask, and then 27.28 g of diethyl maleate was slowly added dropwise to the flask through a constant pressure dropping funnel, while controlling the temperature below 60 °C. After the dropping was completed, the temperature was raised to 90 °C and reacted for 24 h to obtain polyaspartate.

[0045] S2: Under an inert gas atmosphere, 3 g of 4,4'-diisocyanatodicyclohexylmethane was added to a three-necked flask, and 10 mL of N,N-dimethylformamide was added. After quickly adding 3 g of polyetheramine D2000, it was stirred at room temperature for 20 min and then heated to 80 °C for reaction for 2.5 h. After the reaction, the temperature of the three-necked flask was cooled to 10 °C. 0.864 g of polyetheramine T403 was dissolved in 5 mL of DMF and slowly added to the cooled three-necked flask. After stirring at 10 °C for 10 min, an isocyanate prepolymer curing agent was obtained; the curing agent synthesized in this step was one portion.

[0046] S3: 3.98 g of the modified polyaspartate synthesized in step S1 was weighed and stirred and mixed with one portion of the isocyanate prepolymer curing agent synthesized in step S2. After removing bubbles under reduced pressure and vacuum, it was poured into a polytetrafluoroethylene mold and cured at 80 °C for 24 h to obtain a polyurea coating.

[0047] Comparative Example 2

[0048] S1: Raw materials were weighed according to the molar ratio of 4,4'-diaminodicyclohexylmethane (HMDA) to diethyl maleate (DEM) of 1:1.8. Under an inert gas atmosphere, first 16.32 g of 4,4'-diaminodicyclohexylmethane was added to a three-necked flask, and then 24.55 g of diethyl maleate was slowly added dropwise to the flask through a constant pressure dropping funnel, while controlling the temperature below 60 °C during the process. After the dropping was completed, the temperature was raised to 90 °C for reaction for 12 h, and then 3.7 g of KH-560 was added to keep the temperature at 90 °C and continue the reaction for 12 h to obtain polyaspartate.

[0049] S2: Under an inert gas atmosphere, 3 g of 4,4'-diisocyanatodicyclohexylmethane was added to a three-necked flask, and 10 mL of N,N-dimethylformamide was added. After quickly adding 3 g of polyetheramine D2000, it was stirred at room temperature for 20 min and then heated to 80 °C for reaction for 2.5 h. After the reaction, the temperature of the three-necked flask was cooled to 10 °C. 0.864 g of polyetheramine T403 was dissolved in 5 mL of DMF and slowly added to the cooled three-necked flask. After stirring at 10 °C for 10 min, an isocyanate prepolymer curing agent was obtained; the curing agent synthesized in this step was one portion.

[0050] S3: 3.98 g of the modified polyaspartate synthesized in step S1 was weighed and stirred and mixed with one portion of the isocyanate prepolymer curing agent synthesized in step S2. After removing bubbles under reduced pressure and vacuum, it was poured into a polytetrafluoroethylene mold and cured at 80 °C for 24 h to obtain a polyurea coating.

[0051] The materials that were evenly stirred and mixed in step S3 of Examples 1-7 and Comparative Examples 1 and 2 were poured into a polytetrafluoroethylene mold and placed in an oven at 80 °C for curing treatment for 24 h. After drying the solvent, a polyurea coating film with a thickness of 0.5 mm to 0.6 mm was obtained, and a performance evaluation test was carried out:

[0052] (1) Infrared spectroscopy: Fourier transform infrared spectroscopy was used to characterize the modified polyaspartate ester and the finally obtained film, and the results are as Figure 3 , Figure 4 shown. Figure 3 Figure is the infrared spectrogram of the synthesis raw materials in step S1 of Example 1 and the synthesized modified polyaspartate ester sample. The single peak at 3330 cm -1 illustrates the conversion of primary amine to secondary amine. The disappearance of the peak at 1640 cm -1 indicates the completion of the reaction of C=C. The disappearance of the peak at 909 cm -1 proves the reaction of epoxy groups and demonstrates the successful modification of hydrogenated bisphenol A epoxy resin. Figure 4 Figure is the infrared spectrogram of the polyurea coating films obtained in Examples 1-7. The disappearance of the peak near 2260 cm -1 indicates the reaction of -NCO groups, and the complete disappearance also indicates the completion of the reaction.

[0053] (2) Mechanical property test: An electronic universal testing machine was used to test the mechanical properties of the film at a tensile speed of 50 mm / min at 25 °C; the samples were made into dumbbell shapes with dimensions of 75×4×0.5 mm.

[0054] (3) Thermogravimetric analysis: Measured using a TGA STA449F5 instrument, and the measurement conditions were heating from 25 °C to 600 °C at a heating rate of 10 °C / min under a nitrogen flow rate of 30 mL / min.

[0055] (4) Comprehensive property test: The adhesion and pencil hardness of the film were measured according to the provisions of GB / T 9286-2021 and GB / T6739-2006 respectively; the solvent resistance and chemical resistance were measured according to the provisions of GB / T 11547-2008, and the measurement conditions were: (1) The film was soaked in tetrahydrofuran at room temperature for one day, and after drying, the mass before and after soaking was compared to evaluate its solvent resistance; (2) The film was soaked in a 5% mass fraction NaOH solution, a 5% mass fraction H 2 SO 4 solution, and a 3.5% mass fraction NaCl solution at room temperature for one day. After taking out, washing and drying, the mass before and after soaking was compared to evaluate its solvent resistance.

[0056] The above test results are shown in Table 2.

[0057] Table 2 Test Results of Films Prepared in Examples 1-7 and Comparative Examples 1 and 2

[0058]

[0059] As can be seen from Table 2, compared with Comparative Examples 1 and 2, introducing hydrogenated bisphenol A epoxy resin into polyaspartate in the examples can effectively improve the mechanical properties, heat resistance, solvent resistance, and acid and alkali resistance of the cured polyurea coating. Among them, the tensile strength and elongation at break have been significantly improved. Because after the hydrogenated bisphenol A epoxy resin enters, the crosslinking degree of the polyurea coating film curing increases, and the overall toughness is improved, and it has a significant impact on both solvent resistance and corrosion resistance. Compared with the comparative examples, the examples have obvious improvements in mechanical properties and solvent resistance: the tensile strength and gel fraction of the examples are higher than those of the comparative examples. The overall tensile strength and gel fraction first increase and then slightly weaken with the addition of hydrogenated bisphenol A epoxy resin. The tensile strength and gel fraction in the examples can reach up to 35 MPa and 91.86% respectively, which are increased by 98.3% and 18% respectively compared with the comparative examples.

[0060] The above embodiments are relatively suitable implementation manners of the present invention. The implementation manners of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement manners and are all included in the protection scope of the present invention.

Claims

1. A method for preparing a hydrogenated bisphenol A epoxy resin modified polyaspartic acid ester polyurea coating, characterized in that The method comprises the following steps: reacting alicyclic primary diamine with maleic acid ester, adding hydrogenated bisphenol A epoxy resin, and utilizing epoxy group ring-opening reaction to obtain modified polyaspartic acid ester, wherein the molar number of amino groups contained in the alicyclic primary diamine is the sum of the molar number of double bonds contained in maleic acid ester and the molar number of epoxy groups contained in hydrogenated bisphenol A epoxy resin; reacting aliphatic or alicyclic isocyanate with polyether polyamine in a solvent to obtain a curing agent; and mixing the modified polyaspartic acid ester and the curing agent to prepare a hydrogenated bisphenol A epoxy resin modified polyaspartic acid ester polyurea coating.

2. The method for preparing a hydrogenated bisphenol A epoxy resin modified polyaspartic acid ester polyurea coating according to claim 1, characterized in that: The alicyclic primary diamine is a mixture of one or more of 4,4'-diaminodicyclohexylmethane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, isophorone diamine and 1,3'-cyclohexyl diamine; The maleate is a mixture of one or more of dimethyl maleate, diethyl maleate, dipropyl maleate, di-n-butyl maleate and diisobutyl maleate.

3. The method for preparing a hydrogenated bisphenol A epoxy resin modified polyaspartic acid ester polyurea coating according to claim 1, characterized in that: The alicyclic primary diamine is 4,4'-diaminodicyclohexylmethane; the maleate is diethyl maleate; the molar ratio of 4,4'-diaminodicyclohexylmethane to diethyl maleate is 1:1.9 to 1:1.6; the amount of the hydrogenated bisphenol A epoxy resin is 4 to 16% of the total amount of raw materials, and the total amount of raw materials refers to the sum of the masses of 4,4'-diaminodicyclohexylmethane, diethyl maleate and hydrogenated bisphenol A epoxy resin.

4. The method for preparing a hydrogenated bisphenol A epoxy resin modified polyaspartic acid ester polyurea coating according to claim 1, characterized in that: The aliphatic or alicyclic isocyanate is one or more mixtures of hexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate and hexamethylene diisocyanate trimer; The polyether polyamine is one or more mixtures of polyetheramine D230, polyetheramine D400, polyetheramine D2000, polyetheramine D4000, polyetheramine T403 and polyetheramine T5000.

5. The method for preparing a hydrogenated bisphenol A epoxy resin modified polyaspartic acid ester polyurea coating according to claim 1, characterized in that: The alicyclic isocyanate is 4,4'-dicyclohexylmethane diisocyanate; the polyether polyamine is polyetheramine D2000 and polyetheramine T403, and the molar ratio of the two is 0.65:1 to 1.67:1; the amount of polyetheramine T403 is 4 to 10% of the total amount of the curing agent, and the total amount of the curing agent refers to the sum of the masses of 4,4'-dicyclohexylmethane diisocyanate, polyetheramine D2000 and polyetheramine T403.

6. The method for preparing a hydrogenated bisphenol A epoxy resin modified polyaspartic acid ester polyurea coating according to claim 1, characterized in that: The solvent is a mixture of one or more of butyl acetate, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, 1,4-dioxane and propylene glycol methyl ether.

7. A method for preparing a hydrogenated bisphenol A epoxy resin modified polyaspartic acid ester polyurea coating according to any one of claims 1 to 6, characterized in that Follow these steps: S1. Under an inert gas atmosphere, firstly, alicyclic primary diamine is put into a three-necked flask, the flask is assembled into an oil bath, and maleate is added dropwise into the flask with stirring, wherein the temperature of the flask is always controlled below 60° C.; after the maleate is added dropwise, the temperature is raised to 60-100° C. to react for 10-16 hours; S2. Add hydrogenated bisphenol A epoxy resin, raise the temperature and stir the reaction at 100-120° C. for 10-16 hours to obtain modified polyaspartic acid ester; S3. Under an inert gas atmosphere, add 4,4'-diisocyanate dicyclohexylmethane and a solvent to a three-necked flask, then add polyetheramine D2000 and stir at room temperature for 20 minutes, raise the temperature and stir at 70-85°C for 2-3 hours; after the reaction is completed, cool to 10°C with an ice water bath; S4. The polyetheramine T403 was dissolved in N, N-dimethylformamide and added to the three-necked flask after cooling in step S3, and the reaction was continued at 10 ° C. After the reaction was completed, an isocyanate prepolymer curing agent was obtained; S5. The modified polyaspartic acid ester obtained in step S2 and the isocyanate prepolymer curing agent obtained in step S4 are mixed in a functional group molar ratio of NCO:NH=1.05:1, and the mixture is decompressed to -0.09~-0.1MPa, heated to remove the solvent, and cured at 70~90°C for 15~24h to obtain a hydrogenated bisphenol A epoxy resin modified polyaspartic acid ester polyurea coating.

8. The method for preparing a hydrogenated bisphenol A epoxy resin modified polyaspartic acid ester polyurea coating according to claim 7, characterized in that: The reaction in step S1 is to raise the reaction temperature to 90° C. and carry out the reaction for 12 hours; The reaction in step S2 is carried out at 105° C. for 12 h; In step S3, the polyetheramine D2000 is stirred at 105°C and reduced pressure of -0.09 to -0.1 MPa for 2 hours to fully remove moisture before being added; the reaction is carried out at 80°C for 2.5 hours; The reaction time of step S4 is 15 min.

9. A hydrogenated bisphenol A epoxy resin modified polyaspartic acid ester polyurea coating prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the hydrogenated bisphenol A epoxy resin modified polyaspartic acid ester polyurea coating according to claim 9 in surface protection of metal materials.

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