Green bio-based polyurethane wear-resistant anticorrosive coating, and preparation method and use thereof

Abstract

This invention relates to a method for preparing a green bio-based polyurethane wear-resistant and anti-corrosion coating, belonging to the field of high-performance coatings and renewable resource utilization technology. The coating uses hydroxypropyl tea polyphenols (HTP) and castor oil polyols (COP) as the main bio-based raw materials, introduces hexamethylene diisocyanate (HMDI) to form a polyurethane framework, and combines it with aminated graphene oxide (NH2–GO) to enhance the mechanical and anti-corrosion properties of the coating film. The method first prepares three key raw materials: HTP, COP, and NH2–GO. Then, a polyurethane prepolymer is synthesized via a one-step prepolymerization method and synergistically reacted with NH2–GO. Finally, the viscosity of the coating is adjusted by adding leveling agents, UV aging inhibitors, and solvents to obtain the finished coating. The resulting coating exhibits excellent adhesion, wear resistance, corrosion resistance, and anti-aging properties, and is suitable for metal corrosion protection, marine vessel coating, and surface protection of mechanical components, demonstrating significant environmental protection and application promotion value.

Description

Technical Field

[0001] This invention relates to a green bio-based polyurethane wear-resistant and corrosion-resistant coating, its preparation method and uses, belonging to the technical field of functional polymer materials and coating materials. Background Technology

[0002] With the increasing demands for material lifespan and environmental adaptability in industrial equipment, transportation facilities, and marine engineering, functional coatings with excellent wear resistance and corrosion resistance have become a key focus of research and industry. Especially in complex service environments such as high humidity, high salinity, wind erosion, and mechanical friction, traditional coating materials are insufficient to meet long-term protection requirements. In recent years, extensive research both domestically and internationally has focused on developing wear-resistant and corrosion-resistant composite coating systems, achieving significant results. For example, industrialized countries such as the United States, Germany, and Japan have widely applied nano-reinforced epoxy and polyurethane wear-resistant and corrosion-resistant coatings in marine heavy-duty corrosion protection, ship hulls, and steel structure bridges. my country has also been promoting the industrialization of durable protection systems in areas such as rail transportation and energy equipment in recent years. However, most existing materials are still primarily petroleum-based synthetics, facing problems such as high resource consumption and insufficient environmental performance.

[0003] Polyurethane materials, due to their excellent film-forming properties, flexibility, and adhesion, have become a widely used polymer material in current wear-resistant and anti-corrosion coatings. Polyurethane coatings can form dense structures on various metal and non-metal surfaces, providing excellent barrier properties against corrosive media. Simultaneously, their good mechanical properties and wear resistance make them widely applicable in areas such as mechanical equipment housings, anti-corrosion primers, and composite intermediate layers. However, traditional polyurethane systems are mostly derived from petrochemical resources, and their molecular structure contains a high content of flexible segments, resulting in slightly lower weather resistance, thermal stability, and chemical stability compared to epoxy coatings. Furthermore, in complex stress or long-term immersion environments, the coating is prone to blistering, peeling, and aging, limiting its service life in extreme environments.

[0004] Therefore, to further expand the application boundaries of polyurethane coatings, current research focuses on two main aspects: first, introducing bio-based raw materials, such as castor oil, tea polyphenols, and natural polyphenol molecules, to replace some petrochemical raw materials and improve the green environmental performance and structural stability of coatings; second, introducing functional nanomaterials, such as graphene oxide, modified graphene, and inorganic corrosion inhibitors, to improve the wear resistance, corrosion resistance, and aging stability of the coating film. However, how to achieve effective synergy and uniform dispersion of bio-based structures and high-performance nanomaterials remains a significant technical challenge for current polyurethane wear-resistant and anti-corrosion coating systems. Solving this problem is of great significance for developing next-generation polyurethane protective coatings that combine high performance and green sustainability. Summary of the Invention: The purpose of this invention is to provide a green bio-based polyurethane wear-resistant and anti-corrosion coating, its preparation method and uses, in order to solve the above-mentioned problems existing in the prior art.

[0005] This invention is achieved through the following technical solution: A green bio-based polyurethane wear-resistant and corrosion-resistant coating, comprising the following components in parts by weight: Hydroxypropyl tea polyphenols: 20-40 parts; Castor oil polyols: 25 to 50 parts; Hexamethylene diisocyanate: 15 to 25 parts; Aminated graphene oxide: 0.3 to 0.6 parts; Dibutyltin dilaurate: 0.2 to 0.5 parts; Leveling agent: 0.3 to 0.5 parts; Anti-UV aging agent: 0.2 to 0.3 parts; Solvent: 30 to 100 parts.

[0006] As a preferred embodiment, the preparation method of the hydroxypropyl tea polyphenols includes the following steps: Tea polyphenols were dissolved in anhydrous ethanol, sodium hydroxide was added, and propylene oxide was added dropwise under nitrogen protection. After reacting at 60°C, the pH was adjusted to neutral, and the mixture was dialyzed with deionized water in a dialysis bag with a molecular weight cutoff of 1000 Da to obtain the hydroxypropyl tea polyphenols.

[0007] As a preferred embodiment, the mass ratio of tea polyphenols to propylene oxide is (1~3): (2~6).

[0008] As a preferred embodiment, the method for preparing the castor oil polyol includes the following steps: Castor oil and glacial acetic acid were mixed and then hydrogen peroxide aqueous solution was added dropwise. The mixture was reacted at 55°C under the catalysis of concentrated sulfuric acid to obtain epoxidized castor oil. After mixing the epoxy castor oil and ethylene glycol, boron trifluoride ether was added, and the mixture was reacted at 90°C under nitrogen protection to obtain castor oil polyol.

[0009] As a preferred embodiment, the mass ratio of the epoxy castor oil to ethylene glycol is (2~5): (1~3).

[0010] As a preferred embodiment, the preparation method of the aminated graphene oxide includes the following steps: Graphene oxide was added to N,N-dimethylformamide and ultrasonically dispersed to obtain a black graphene oxide dispersion. 1,6-hexanediamine was added dropwise to the graphene oxide dispersion to carry out the reaction and obtain aminated graphene oxide.

[0011] As a preferred embodiment, the mass ratio of graphene oxide to hexamethylenediamine is (1~2):(5~10).

[0012] As a preferred embodiment, the solvent is a mixture of N,N-dimethylformamide and ethyl acetate, wherein the volume ratio of N,N-dimethylformamide to ethyl acetate is 1:1.

[0013] A method for preparing a green bio-based polyurethane wear-resistant and corrosion-resistant coating as described above includes the following steps: Aminated graphene oxide was ultrasonically dispersed in ethyl acetate to obtain an aminated graphene oxide dispersion. Hydroxypropyl tea polyphenols were dissolved in N,N-dimethylformamide, and hexamethylene diisocyanate was added. The reaction was carried out at 90°C to obtain a polyurethane prepolymer. The polyurethane prepolymer was added to the aminated graphene oxide dispersion, mixed well, and then dibutyltin dilaurate was added. After reacting at 75°C, castor oil polyol was added, and the reaction was carried out to obtain a bio-based polyurethane mixture. A leveling agent and an anti-UV aging agent are added sequentially to the bio-based polyurethane mixture, and solvent is added to adjust the viscosity to obtain the green bio-based polyurethane wear-resistant and anti-corrosion coating.

[0014] The use of a green bio-based polyurethane wear-resistant and corrosion-resistant coating as described above in metal anti-corrosion coatings, marine and ship coatings, and surface coatings for mechanical equipment and wear-resistant components.

[0015] The basic principle of this invention: 1) Using hydroxypropyl tea polyphenols (HTP) and castor oil polyols (COP) as the main polyhydroxy components, they react with hexamethylene diisocyanate (HMDI) to construct a bio-based polyurethane backbone with high crosslinking density, thus achieving an organic combination of green-sourced raw materials and flexible structure.

[0016] 2) By introducing NH2–GO with active amino groups on its surface, it can be covalently grafted with polyurethane segments, thereby improving the dispersion stability and interfacial bonding force of graphene in the composite material, thus enhancing the mechanical properties of the coating and its ability to shield against corrosive media.

[0017] 3) Introduce leveling agents and UV aging inhibitors into the coating to synergistically regulate the surface uniformity and weather resistance of the coating film, thereby improving its service stability and service life in outdoor or harsh environments.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1) This invention uses HTP and COP obtained from renewable resources as polyurethane matrix, which makes the resulting coating not only have good adhesion and wear resistance, but also significantly improve environmental protection and sustainability.

[0019] 2) The coating incorporates NH2–GO to construct a nano-shielding network structure, which effectively blocks the diffusion of moisture and corrosive ions, significantly extending the protection life. After salt spray resistance time of over 500 hours, there is no blistering or rust on the surface.

[0020] 3) The coating system has good fluidity and is suitable for various construction methods such as spraying, brushing or scraping. It can be cured at room temperature or low temperature and is compatible with various substrates such as metal, plastic and composite board. It has good practicality and industrial application prospects. Attached Figure Description

[0021] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a flowchart illustrating the preparation process of the green bio-based polyurethane wear-resistant and corrosion-resistant coating prepared in Example 1 of the present invention. Detailed Implementation

[0022] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0023] Example 1 This embodiment relates to a method for preparing a green bio-based polyurethane wear-resistant and corrosion-resistant coating, specifically including the following steps: 1) Preparation of aminated graphene oxide (NH2–GO) 0.50 g of graphene oxide (GO) was weighed and added to 100 mL of N,N-dimethylformamide (DMF), and ultrasonically dispersed to obtain a black GO dispersion. 2.00 g of 1,6-hexanediamine (HDA) was slowly added dropwise to the dispersion, and the mixture was magnetically stirred for 6 h. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain aminated graphene oxide (NH2–GO).

[0024] 2) Preparation of hydroxypropyl tea polyphenols (HTP) 5.00 g of tea polyphenols were dissolved in 100 mL of anhydrous ethanol, and 0.50 g of NaOH was added as a catalyst. Under nitrogen protection, 8.00 g of propylene oxide was slowly added dropwise, and the reaction was carried out at 60 °C for 6 h. After the reaction was completed, the pH was adjusted to neutral with dilute hydrochloric acid, and the product was placed in a dialysis bag with a molecular weight cutoff of 1000 Da and dialyzed against deionized water for 48 h to remove small molecule impurities. The sample was freeze-dried to obtain hydroxypropyl tea polyphenols (HTP).

[0025] 3) Preparation of castor oil polyol (COP) 50 g of castor oil and 40 mL of glacial acetic acid were added to a three-necked flask. 50 mL of 30% hydrogen peroxide solution was slowly added dropwise, along with 1 mL of concentrated sulfuric acid as a catalyst. The mixture was stirred at 55 °C for 3 h. After the reaction was complete, excess acid was neutralized with saturated NaHCO3 solution. The mixture was allowed to stand and separate into layers, and the oil phase was repeatedly washed with distilled water until neutral. Hydrogen was removed by rotary evaporation to obtain epoxidized castor oil. 40 g of epoxidized castor oil and 30 g of ethylene glycol were added to a three-necked flask, along with 0.5 g of boron trifluoride ether (BF3·Et2O). The mixture was reacted at 90 °C for 5 h under nitrogen protection. After the reaction was complete, residual acid was neutralized with saturated NaHCO3 solution, and the organic solvent was removed by extraction with ethyl acetate and rotary evaporation. The mixture was then dried under vacuum to obtain castor oil polyol (COP).

[0026] Prepare the ingredients according to the following proportions: Hydroxypropyl tea polyphenols (HTP) 30 parts; Castor oil polyol (COP) 25 parts; 20 parts of hexamethylene diisocyanate (HMDI); 0.4 parts of aminated graphene oxide (NH2–GO); 0.2 parts of dibutyltin dilaurate (DBTDL); 0.3 parts of leveling agent (such as BYK-306); 0.2 parts of anti-UV aging agent; 50 parts of ethyl acetate / DMF (volume ratio 1:1) mixed solvent; NH2–GO was ultrasonically dispersed in 80 mL of ethyl acetate to obtain a 0.50% NH2–GO dispersion. HTP was dissolved in DMF, hexamethylene diisocyanate (HMDI) was added, and the mixture was stirred at 90 °C for 3 h to obtain a polyurethane prepolymer. The polyurethane prepolymer was added to the NH2–GO dispersion, and magnetic stirring was used to ensure thorough mixing of NH2–GO and the polyurethane prepolymer. Dibutyltin dilaurate (DBTDL) was added, and the mixture was reacted at 75 °C for 3 h. COP was then added to the reaction solution, and the reaction was continued for 6 h to obtain a bio-based polyurethane mixture. A leveling agent (such as BYK-306) and an anti-UV aging agent were added sequentially to the mixture to adjust the final viscosity (the mixed solvent could be added as needed), and the mixture was stirred until homogeneous to obtain a bio-based polyurethane coating.

[0027] The bio-based polyurethane coating prepared in Example 1 showed adhesion test results that met the GB / T 9286 standard, with a cross-cut adhesion rating of 0-1. Under the ASTM D4060 standard, the abrasion resistance, tested by the Taber abrasion tester, showed a mass loss of 25 mg at 500 revolutions. According to the ASTM B117 neutral salt spray test standard, the coating withstood salt spray corrosion in 5% NaCl solution for more than 500 hours, and no obvious blistering, peeling, or rust was observed on the coating surface.

[0028] Example 2 This embodiment relates to a method for preparing a green bio-based polyurethane wear-resistant and corrosion-resistant coating, specifically including the following steps: 1) Preparation of aminated graphene oxide (NH2–GO) 0.60 g of graphene oxide (GO) was weighed and added to 100 mL of N,N-dimethylformamide (DMF), and ultrasonically dispersed to obtain a black GO dispersion. 2.5 g of 1,6-hexanediamine (HDA) was slowly added dropwise to the dispersion, and the mixture was magnetically stirred for 6 h. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain aminated graphene oxide (NH2–GO).

[0029] 2) Preparation of hydroxypropyl tea polyphenols (HTP) 6.00 g of tea polyphenols were dissolved in 100 mL of anhydrous ethanol, and 0.50 g of NaOH was added as a catalyst. Under nitrogen protection, 9.00 g of propylene oxide was slowly added dropwise, and the reaction was carried out at 60 °C for 6 h. After the reaction was completed, the pH was adjusted to neutral with dilute hydrochloric acid, and the product was placed in a dialysis bag with a molecular weight cutoff of 1000 Da and dialyzed against deionized water for 48 h to remove small molecule impurities. The sample was freeze-dried to obtain hydroxypropyl tea polyphenols (HTP).

[0030] 3) Preparation of castor oil polyol (COP) 45 g of castor oil and 40 mL of glacial acetic acid were added to a three-necked flask. 50 mL of 30% hydrogen peroxide solution was slowly added dropwise, along with 1 mL of concentrated sulfuric acid as a catalyst. The mixture was stirred at 55 °C for 3 h. After the reaction was complete, excess acid was neutralized with saturated NaHCO3 solution. The mixture was allowed to stand and separate into layers, and the oil phase was repeatedly washed with distilled water until neutral. Hydrogen was removed by rotary evaporation to obtain epoxidized castor oil. 45 g of epoxidized castor oil and 35 g of ethylene glycol were added to a three-necked flask, along with 0.5 g of boron trifluoride ether (BF3·Et2O). The mixture was reacted at 90 °C for 5 h under nitrogen protection. After the reaction was complete, residual acid was neutralized with saturated NaHCO3 solution, and the organic solvent was removed by extraction with ethyl acetate and rotary evaporation. The mixture was then dried under vacuum to obtain castor oil polyol (COP).

[0031] Prepare the ingredients according to the following proportions: Hydroxypropyl tea polyphenols (HTP) 35 parts; 30 parts castor oil polyol (COP); 25 parts of hexamethylene diisocyanate (HMDI); 0.3 parts of aminated graphene oxide (NH2–GO); 0.25 parts of dibutyltin dilaurate (DBTDL); Leveling agent (such as BYK-306) 0.35 parts; 0.25 parts of anti-UV aging agent; 60 parts of ethyl acetate / DMF (volume ratio 1:1) mixed solvent; 0.50% NH2–GO was ultrasonically dispersed in 80 mL of ethyl acetate to obtain an NH2–GO dispersion. HTP was dissolved in DMF, and hexamethylene diisocyanate (HMDI) was added. The mixture was stirred at 90 °C for 3 h to obtain a polyurethane prepolymer. The polyurethane prepolymer was added to the NH2–GO dispersion, and magnetic stirring was used to ensure thorough mixing of NH2–GO and the polyurethane prepolymer. Dibutyltin dilaurate (DBTDL) was added, and the mixture was reacted at 75 °C for 3 h. COP was then added to the reaction solution, and the reaction was continued for 6 h to obtain a bio-based polyurethane mixture. A leveling agent (such as BYK-306) and an anti-UV aging agent were added sequentially to the mixture to adjust the final viscosity (the mixed solvent could be added as needed). The mixture was stirred until homogeneous to obtain a bio-based polyurethane coating.

[0032] The bio-based polyurethane coating prepared in Example 2 showed adhesion test results that met the GB / T 9286 standard, with a cross-cut adhesion rating of 0-1. Under the ASTM D4060 standard, the abrasion resistance, tested by the Taber abrasion tester, showed a mass loss of 26 mg at 500 revolutions. According to the ASTM B117 neutral salt spray test standard, the coating withstood salt spray corrosion in 5% NaCl solution for more than 500 hours, and no obvious blistering, peeling, or rust was observed on the coating surface.

[0033] Example 3 This embodiment relates to a method for preparing a green bio-based polyurethane wear-resistant and corrosion-resistant coating, specifically including the following steps: 1) Preparation of aminated graphene oxide (NH2–GO) 0.50 g of graphene oxide (GO) was weighed and added to 100 mL of N,N-dimethylformamide (DMF), and ultrasonically dispersed to obtain a black GO dispersion. 3.0 g of 1,6-hexanediamine (HDA) was slowly added dropwise to the dispersion, and the mixture was magnetically stirred for 6 h. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain aminated graphene oxide (NH2–GO).

[0034] 2) Preparation of hydroxypropyl tea polyphenols (HTP) 5.50 g of tea polyphenols were dissolved in 100 mL of anhydrous ethanol, and 0.50 g of NaOH was added as a catalyst. Under nitrogen protection, 9.50 g of propylene oxide was slowly added dropwise, and the reaction was carried out at 60 °C for 6 h. After the reaction was completed, the pH was adjusted to neutral with dilute hydrochloric acid, and the product was placed in a dialysis bag with a molecular weight cutoff of 1000 Da and dialyzed against deionized water for 48 h to remove small molecule impurities. The sample was freeze-dried to obtain hydroxypropyl tea polyphenols (HTP).

[0035] 3) Preparation of castor oil polyol (COP) 50 g of castor oil and 40 mL of glacial acetic acid were added to a three-necked flask. 50 mL of 30% hydrogen peroxide solution was slowly added dropwise, along with 1 mL of concentrated sulfuric acid as a catalyst. The mixture was stirred at 55 °C for 3 h. After the reaction was complete, excess acid was neutralized with saturated NaHCO3 solution. The mixture was allowed to stand and separate into layers, and the oil phase was repeatedly washed with distilled water until neutral. Hydrogen was removed by rotary evaporation to obtain epoxidized castor oil. 50 g of epoxidized castor oil and 40 g of ethylene glycol were added to a three-necked flask, along with 0.5 g of boron trifluoride ether (BF3·Et2O). The mixture was reacted at 90 °C for 5 h under nitrogen protection. After the reaction was complete, residual acid was neutralized with saturated NaHCO3 solution, and the organic solvent was removed by extraction with ethyl acetate and rotary evaporation. The mixture was then dried under vacuum to obtain castor oil polyol (COP).

[0036] Prepare the ingredients according to the following proportions: Hydroxypropyl tea polyphenols (HTP) 40 parts; Castor oil polyol (COP) 40 parts; 20 parts of hexamethylene diisocyanate (HMDI); 0.4 parts of aminated graphene oxide (NH2–GO); 0.3 parts of dibutyltin dilaurate (DBTDL); 0.3 parts of leveling agent (such as BYK-306); 0.3 parts of anti-UV aging agent; 70 parts of ethyl acetate / DMF (volume ratio 1:1) mixed solvent; 0.50% NH2–GO was ultrasonically dispersed in 80 mL of ethyl acetate to obtain an NH2–GO dispersion. HTP was dissolved in DMF, and hexamethylene diisocyanate (HMDI) was added. The mixture was stirred at 90 °C for 3 h to obtain a polyurethane prepolymer. The polyurethane prepolymer was added to the NH2–GO dispersion, and magnetic stirring was used to ensure thorough mixing of NH2–GO and the polyurethane prepolymer. Dibutyltin dilaurate (DBTDL) was added, and the mixture was reacted at 75 °C for 3 h. COP was then added to the reaction solution, and the reaction was continued for 6 h to obtain a bio-based polyurethane mixture. A leveling agent (such as BYK-306) and an anti-UV aging agent were added sequentially to the mixture to adjust the final viscosity (the mixed solvent could be added as needed). The mixture was stirred until homogeneous to obtain a bio-based polyurethane coating.

[0037] The bio-based polyurethane coating prepared in Example 3 showed adhesion test results that met the GB / T 9286 standard, with a cross-cut adhesion rating of 0-1. Under the ASTM D4060 standard, the abrasion resistance, tested by the Taber abrasion tester, showed a mass loss of 25 mg at 500 revolutions. According to the ASTM B117 neutral salt spray test standard, the coating withstood salt spray corrosion in 5% NaCl solution for more than 500 hours, and no obvious blistering, peeling, or rust was observed on the coating surface.

[0038] Comparative Example 1 The difference from Example 1 is that the amount of aminated graphene oxide added in the preparation method is 0, resulting in a bio-based polyurethane coating. Adhesion test results meet GB / T 9286 standard, with a cross-cut adhesion rating of 1-2. Under ASTM D4060 standard, the abrasion resistance, tested by the Taber abrasion tester, showed a mass loss of 30 mg at 500 revolutions. According to ASTM B117 neutral salt spray test standard, the coating withstood salt spray corrosion in 5% NaCl solution for over 500 hours, with no obvious blistering, peeling, or corrosion observed on the coating surface.

[0039] Comparative Example 2 The difference from Example 1 is that "tea polyphenols" were used instead of "hydroxypropyl tea polyphenols" in the preparation method, resulting in a bio-based polyurethane coating. Adhesion test results met GB / T 9286 standards, with a cross-cut adhesion rating of 1-2. Under ASTM D4060 standards, the abrasion resistance, tested by the Taber abrasion tester, showed a mass loss of 31 mg at 500 revolutions. According to ASTM B117 neutral salt spray test standards, the coating withstood salt spray corrosion in a 5% NaCl solution for over 500 hours, with no obvious blistering, peeling, or corrosion observed on the coating surface.

[0040] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A green bio-based polyurethane wear-resistant and anti-corrosion coating, characterized in that, Includes the following components by weight: Hydroxypropyl tea polyphenols: 20-40 parts; Castor oil polyols: 25 to 50 parts; Hexamethylene diisocyanate: 15 to 25 parts; Aminated graphene oxide: 0.3 to 0.6 parts; Dibutyltin dilaurate: 0.2 to 0.5 parts; Leveling agent: 0.3 to 0.5 parts; Anti-UV aging agent: 0.2 to 0.3 parts; Solvent: 30 to 100 parts.

2. The green bio-based polyurethane wear-resistant and anti-corrosion coating according to claim 1, characterized in that, The preparation method of the hydroxypropyl tea polyphenol includes the following steps: Tea polyphenols were dissolved in anhydrous ethanol, sodium hydroxide was added, and propylene oxide was added dropwise under nitrogen protection. After reacting at 60°C, the pH was adjusted to neutral, and the mixture was dialyzed with deionized water in a dialysis bag with a molecular weight cutoff of 1000 Da to obtain the hydroxypropyl tea polyphenols.

3. The green bio-based polyurethane wear-resistant and anti-corrosion coating according to claim 2, characterized in that, The mass ratio of tea polyphenols to propylene oxide is (1~3): (2~6).

4. The green bio-based polyurethane wear-resistant and anti-corrosion coating according to claim 1, characterized in that, The preparation method of the castor oil polyol includes the following steps: Castor oil and glacial acetic acid were mixed and then hydrogen peroxide aqueous solution was added dropwise. The mixture was reacted at 55°C under the catalysis of concentrated sulfuric acid to obtain epoxidized castor oil. After mixing the epoxy castor oil and ethylene glycol, boron trifluoride ether was added, and the mixture was reacted at 90°C under nitrogen protection to obtain castor oil polyol.

5. The green bio-based polyurethane wear-resistant and anti-corrosion coating according to claim 4, characterized in that, The mass ratio of the epoxy castor oil to ethylene glycol is (2~5): (1~3).

6. The green bio-based polyurethane wear-resistant and anti-corrosion coating according to claim 1, characterized in that, The preparation method of the aminated graphene oxide includes the following steps: Graphene oxide was added to N,N-dimethylformamide and ultrasonically dispersed to obtain a black graphene oxide dispersion. 1,6-hexanediamine was added dropwise to the graphene oxide dispersion to carry out the reaction and obtain aminated graphene oxide.

7. The green bio-based polyurethane wear-resistant and anti-corrosion coating as described in claim 6, characterized in that, The mass ratio of graphene oxide to hexamethylenediamine is (1~2): (5~10).

8. The green bio-based polyurethane wear-resistant and anti-corrosion coating as described in claim 1, characterized in that, The solvent is a mixture of N,N-dimethylformamide and ethyl acetate, wherein the volume ratio of N,N-dimethylformamide to ethyl acetate is 1:

1.

9. A method for preparing a green bio-based polyurethane wear-resistant and anti-corrosion coating as described in any one of claims 1 to 8, characterized in that, Includes the following steps: Aminated graphene oxide was ultrasonically dispersed in ethyl acetate to obtain an aminated graphene oxide dispersion. Hydroxypropyl tea polyphenols were dissolved in N,N-dimethylformamide, and hexamethylene diisocyanate was added. The reaction was carried out at 90°C to obtain a polyurethane prepolymer. The polyurethane prepolymer was added to the aminated graphene oxide dispersion, mixed well, and then dibutyltin dilaurate was added. After reacting at 75°C, castor oil polyol was added, and the reaction was carried out to obtain a bio-based polyurethane mixture. A leveling agent and an anti-UV aging agent are added sequentially to the bio-based polyurethane mixture, and solvent is added to adjust the viscosity to obtain the green bio-based polyurethane wear-resistant and anti-corrosion coating.

10. The use of the green bio-based polyurethane wear-resistant and corrosion-resistant coating as described in claim 1 in metal anti-corrosion coatings, marine and ship coatings, and surface coatings for mechanical equipment and wear-resistant components.

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