Preparation method and application of waterborne polyurethane acrylate wear-resistant anticorrosive paint

Abstract

The invention provides a preparation method of a waterborne polyurethane acrylate wear-resistant anticorrosive coating, which comprises the following steps: (1) in the presence of sodium methoxide as a catalyst, diethanol amine reacts with palm oil, so that active hydroxyl groups are grafted on the surface of the palm oil, which is beneficial to the subsequent reaction of waterborne polyurethane; (2) performing reaction on isophorone diisocyanate, the modified palm oil and pentaerythritol triacrylate to obtain waterborne polyurethane acrylate; and (3) grafting isophorone diisocyanate onto the graphene, and then reacting the graphene graft with N, N-dimethylethanolamine, so that more active sites are provided for the surface of the graphene after grafting, and the dispersity and compatibility of the graphene are improved. The method is simple and convenient to operate and few in process steps; the reaction time is short and the energy consumption is low; the raw materials are cheap, easily available and environment-friendly; the prepared waterborne polyurethane acrylate coating is good in wear resistance and corrosion resistance.

Description

Technical Field

[0001] The invention relates to a method for preparing a waterborne polyurethane acrylate wear-resistant and anticorrosive coating, and belongs to the field of polymer materials and composite materials. Background Art

[0002] At present, common metal anti-corrosion coatings can be divided into the following main types according to their composition and anti-corrosion mechanism: epoxy resin anti-corrosion coatings, polyurethane anti-corrosion coatings, acrylic anti-corrosion coatings, fluorocarbon anti-corrosion coatings, zinc-based anti-corrosion coatings, inorganic zinc silicate anti-corrosion coatings, and polysiloxane anti-corrosion coatings. Compared with other anti-corrosion coatings, polyurethane coatings have good weather resistance, wear resistance, and chemical corrosion resistance. At the same time, they also have certain flexibility and mechanical strength, and can adapt to temperature differences and micro-deformation of the substrate. They are widely used in the protection of outdoor steel structures, such as bridges, storage tanks, ships, and mechanical equipment. Traditional polyurethane anti-corrosion coatings are mainly solvent-based, and solvent-based polyurethane anti-corrosion coatings have brought huge environmental pollution to the environment and construction. Compared with ordinary solvent-based polyurethane coatings, waterborne polyurethane coatings have better environmental protection performance, safety, and construction convenience.

[0003] How to further improve the anti-corrosion performance of waterborne polyurethane anti-corrosion coatings? Currently, the following methods are mainly used: by modifying the polyurethane matrix, introducing more monomers or segments with anti-corrosion functions, such as polymers containing fluorine or silicon elements, to improve the chemical resistance and weather resistance of the coating; introducing zinc powder (such as zinc-rich primer) into waterborne polyurethane to protect the substrate through the sacrificial anode effect of zinc to form a self-healing anti-corrosion coating. Adding nanomaterials (such as nano-silicon dioxide, nano-alumina, etc.) can improve the density of the coating, making it difficult for corrosive substances to penetrate into the metal surface, thereby enhancing the anti-corrosion effect; by introducing super-hydrophobic nanomaterials or adding hydrophobic additives, the surface energy of the coating can be reduced, making the coating waterproof and self-cleaning, and reducing the erosion of water on the substrate. Under the premise of ensuring the flatness and adhesion of the coating film, by reasonably increasing the coating thickness, the shielding effect of the anti-corrosion coating can be improved and the penetration of the corrosive medium can be delayed; by pre-treating the metal substrate (such as sandblasting, phosphating, pickling, etc.) to enhance the adhesion between the substrate and the coating, the coating and the metal substrate are more closely combined to prevent the coating from falling off or blistering, thereby improving the anti-corrosion effect. Adding functional anti-corrosion coatings, graphene as a new functional filler, graphene has excellent conductivity and barrier properties, which can significantly improve the anti-corrosion and antioxidant properties of the coating. However, graphene is easy to agglomerate during use, which greatly affects its dispersibility and compatibility, thereby affecting the anti-corrosion effect of the entire system. Therefore, how to improve the compatibility of graphene has become a hot topic in scientific research. Summary of the invention The object of the present invention is to provide a preparation method of a waterborne polyurethane acrylate wear-resistant and anti-corrosion coating and its use, so as to solve the above-mentioned problems existing in the prior art.

[0005] The present invention is achieved through the following technical solutions: A method for preparing a waterborne polyurethane acrylate wear-resistant and anti-corrosion coating comprises the following steps: A waterborne polyurethane acrylate emulsion and modified graphene are prepared respectively; The modified graphene and sodium dodecylbenzene sulfonate are dispersed in an ethanol solution with a mass concentration of 5%. After uniform dispersion, polytetrafluoroethylene powder and the aqueous polyurethane acrylate emulsion are added. After grinding and dispersion, a defoamer and a leveling agent are added. Finally, the mixture is dispersed by high-speed stirring to obtain an aqueous polyurethane acrylate wear-resistant and anti-corrosion coating.

[0006] As a preferred embodiment, the preparation method of the aqueous polyurethane acrylate emulsion is: After isophorone diisocyanate, modified palm oil and pentaerythritol triacrylate are mixed, dibutyltin dilaurate is added dropwise, and the mixture is reacted at 55-60°C to obtain a precursor; Add dihydroxymethylpropionic acid to the precursor, react at 55-60° C., cool to room temperature, add triethylamine, stir at 300-500 rpm, add deionized water, stir at 800-1200 rpm to obtain an aqueous polyurethane acrylate emulsion.

[0007] As a preferred embodiment, the mass ratio of isophorone diisocyanate to modified palm oil is (4-8):(5-10).

[0008] As a preferred embodiment, the preparation method of the modified palm oil is: Palm oil, diethanolamine and sodium methoxide are mixed and reacted at 140-160°C under the protection of nitrogen, then cooled to room temperature, saturated brine is added, shaken and allowed to stand, and extracted with carbon tetrachloride to obtain modified palm oil.

[0009] As a preferred embodiment, the mass ratio of palm oil to diethanolamine is (2-5): (1-2).

[0010] As a preferred embodiment, the preparation method of the modified graphene is: Graphene was dispersed in acetone, isophorone diisocyanate and dibutyltin dilaurate were added, and the reaction was carried out at 80-85°C under the protection of nitrogen, and then the temperature was lowered to 60-70°C and added. N,N -dimethylethanolamine, after continuing the reaction, the product is washed with acetone and deionized water, and finally freeze-dried to obtain modified graphene.

[0011] As a preferred embodiment, the rotation speed of the high-speed stirring is 1000 rpm.

[0012] As a preferred solution, the defoaming agent is selected from polysiloxane defoaming agents, and the leveling agent is selected from polyvinyl alcohol leveling agents.

[0013] A use of the waterborne polyurethane acrylate wear-resistant and anti-corrosion coating obtained by the above-mentioned preparation method in metal wear-resistant and anti-corrosion.

[0014] The basic implementation principle of the present invention is: 1. In the presence of sodium methoxide as a catalyst, diethanolamine is reacted with palm oil to graft a large number of active hydroxyl groups on the surface of palm oil, which is beneficial to the subsequent reaction of waterborne polyurethane.

[0015] 2. Isophorone diisocyanate, palm oil and pentaerythritol triacrylate are subjected to addition reaction with dibutyltin dilaurate as a catalyst to generate carbamate groups. Finally, polyurethane acrylate is reacted with dihydroxymethylpropionic acid and triethylamine in sequence to improve the water solubility of polyurethane acrylate.

[0016] 3. Grafting isophorone diisocyanate onto graphene, and then grafting the graphene N,N -dimethylethanolamine reaction, which provides more active sites for the graphene surface after grafting.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. Compared with ordinary polyurethane resins, the system based on palm oil-based water-based polyurethane acrylate is biodegradable, which greatly reduces the pollution to the environment.

[0018] 2. Isophorone diisocyanate and N,N -Dimethylethanolamine is grafted onto graphene, which improves the compatibility of graphene with water-based polyurethane resin, overcomes the problems of easy agglomeration and poor dispersion of graphene, and greatly improves the anti-corrosion performance of graphene.

[0019] 3. Pentaerythritol triacrylate is added to the reaction system. Compared with polyurethane, polyurethane acrylate has stronger hardness, wear resistance and scratch resistance, thus improving the wear resistance of the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings: Figure 1 This is a flow chart for preparing the waterborne polyurethane acrylate wear-resistant and anti-corrosion coating of Example 1. DETAILED DESCRIPTION

[0021] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0022] Example 1 (1) Preparation of modified palm oil 1 g palm oil, 0.5 g diethanolamine and 0.02 g sodium methoxide were added to a three-necked flask, and reacted at 150 °C for 2 h under nitrogen protection. After the reaction stopped, the temperature was quickly lowered to room temperature. The reactants were added to saturated saline, shaken and still, and carbon tetrachloride was added to extract to obtain modified palm oil.

[0023] (2) Preparation of waterborne polyurethane acrylate emulsion 4.0 g of isophorone diisocyanate, 5.0 g of modified palm oil and 1.0 g of pentaerythritol triacrylate were added into a three-necked flask, 0.05 g of dibutyltin dilaurate was added dropwise, the mixture was reacted at 55 °C for 30 min, 1.0 g of dihydroxymethylpropionic acid was added after cooling to room temperature, the mixture was reacted at 55 °C for 2 h, the mixture was cooled to room temperature, 1.0 g of triethylamine was added, the mixture was stirred at 300 rpm for 5 min, 30 mL of deionized water was added, the mixture was stirred at 1000 rpm for 30 min, and an aqueous polyurethane acrylate emulsion was obtained.

[0024] (3) Preparation of modified graphene 1.0 g of graphene was dispersed in 300 mL of acetone. 50 g of isophorone diisocyanate and 0.02 g of dibutyltin dilaurate were added to the dispersion and reacted at 85 °C with magnetic stirring for 12 h under nitrogen. The reaction temperature was lowered to 65 °C and 30 g of N,N -dimethylethanolamine, the reaction was continued for 2 h, and the product was washed with acetone and deionized water and freeze-dried to obtain modified graphene.

[0025] (4) Preparation of waterborne polyurethane acrylate wear-resistant and anti-corrosion coating 0.3 g of modified graphene and 0.3 g of sodium dodecylbenzene sulfonate were dispersed in 100 mL of alcohol solution (5 wt%) and ultrasonically dispersed for 1 hour. 0.1 g of polytetrafluoroethylene powder and 100 g of aqueous polyurethane acrylate emulsion were added, and the mixture was ground and dispersed using a ball mill for 6 hours. Finally, 2 g of polysiloxane defoamer and 3 g of polyvinyl alcohol leveling agent were added respectively, and the mixture was stirred and dispersed at 1000 rpm in a high-speed stirrer for 10 min to obtain a waterborne polyurethane acrylate wear-resistant and anti-corrosion coating.

[0026] The coating prepared in Example 1 has an adhesion of level 0 and a hardness of 3H. The salt spray resistance test shows that after the coating is immersed for 500 h, no corrosion products or rust are generated. The electrochemical test results show that the corrosion potential of the coating is -0.489 mV and the corrosion current is 1.92×10 -7 nA / cm 2 The corrosion efficiency is 0.004 mm / a. Figure 1 shown.

[0027] Example 2 (1) Preparation of modified palm oil 1.2 g palm oil, 0.6 g diethanolamine and 0.02 g sodium methoxide were added to a three-necked flask and reacted at 150 °C for 3 h under nitrogen protection. After the reaction stopped, the temperature was quickly lowered to room temperature. The reactants were added to saturated saline, shaken and still, and carbon tetrachloride was added to extract to obtain modified palm oil.

[0028] (2) Preparation of waterborne polyurethane acrylate emulsion 6.0 g of isophorone diisocyanate, 5.0 g of modified palm oil and 1.5 g of pentaerythritol triacrylate were added into a three-necked flask, 0.05 g of dibutyltin dilaurate was added dropwise, the mixture was reacted at 55 °C for 30 min, 0.8 g of dihydroxymethylpropionic acid was added after the mixture was cooled to room temperature, the mixture was reacted at 55 °C for 2 h, the mixture was cooled to room temperature, 1.0 g of triethylamine was added, the mixture was stirred at 300 rpm for 5 min, 30 mL of deionized water was added, the mixture was stirred at 1000 rpm for 30 min, and an aqueous polyurethane acrylate emulsion was obtained.

[0029] (3) Preparation of modified graphene 1.5 g of graphene was dispersed in 300 mL of acetone. 60 g of isophorone diisocyanate and 0.02 g of dibutyltin dilaurate were added to the dispersion and reacted at 85 °C with magnetic stirring for 12 h under nitrogen. The reaction temperature was lowered to 65 °C and 30 g of N,N -dimethylethanolamine, the reaction was continued for 2 h, and the product was washed with acetone and deionized water and freeze-dried to obtain modified graphene.

[0030] (4) Preparation of waterborne polyurethane acrylate wear-resistant and anti-corrosion coating 0.3 g of modified graphene and 0.3 g of sodium dodecylbenzene sulfonate were dispersed in 100 mL of alcohol solution (5 wt%) and ultrasonically dispersed for 1 hour. 0.1 g of polytetrafluoroethylene powder and 100 g of aqueous polyurethane acrylate emulsion were added, and the mixture was ground and dispersed using a ball mill for 6 hours. Finally, 2 g of polysiloxane defoamer and 3 g of polyvinyl alcohol leveling agent were added respectively, and the mixture was stirred and dispersed at 1000 rpm in a high-speed stirrer for 10 min to obtain a waterborne polyurethane acrylate wear-resistant and anti-corrosion coating.

[0031] The coating prepared in Example 2 has an adhesion of level 0 and a hardness of 3H. The salt spray resistance test shows that after the coating is immersed for 500 h, no corrosion products or rust are generated. The electrochemical test results show that the corrosion potential of the coating is -0.512 mV and the corrosion current is 1.89×10 -7 nA / cm 2 , the corrosion efficiency is 0.0035 mm / a.

[0032] Example 3 (1) Preparation of modified palm oil 1.0 g palm oil, 0.55 g diethanolamine and 0.02 g sodium methoxide were added to a three-necked flask and reacted at 160 °C for 3 h under nitrogen protection. After the reaction stopped, the temperature was quickly lowered to room temperature. The reactants were added to saturated saline, shaken and still, and carbon tetrachloride was added to extract to obtain modified palm oil.

[0033] (2) Preparation of waterborne polyurethane acrylate emulsion 5.0 g of isophorone diisocyanate, 5.0 g of modified palm oil and 1.2 g of pentaerythritol triacrylate were added into a three-necked flask, 0.05 g of dibutyltin dilaurate was added dropwise, the mixture was reacted at 55 °C for 30 min, 0.8 g of dihydroxymethylpropionic acid was added after the mixture was cooled to room temperature, the mixture was reacted at 55 °C for 2 h, the mixture was cooled to room temperature, 1.0 g of triethylamine was added, the mixture was stirred at 300 rpm for 5 min, 30 mL of deionized water was added, the mixture was stirred at 1000 rpm for 30 min, and an aqueous polyurethane acrylate emulsion was obtained.

[0034] (3) Preparation of modified graphene 1.5 g of graphene was dispersed in 300 mL of acetone. 50 g of isophorone diisocyanate and 0.02 g of dibutyltin dilaurate were added to the dispersion and stirred under nitrogen at 85 °C for 12 h. The reaction temperature was lowered to 65 °C and 30 g of N,N -dimethylethanolamine, the reaction was continued for 2 h, and the product was washed with acetone and deionized water and freeze-dried to obtain modified graphene.

[0035] (4) Preparation of waterborne polyurethane acrylate wear-resistant and anti-corrosion coating 0.3 g of modified graphene and 0.3 g of sodium dodecylbenzene sulfonate were dispersed in 100 mL of alcohol solution (5 wt%) and ultrasonically dispersed for 1 hour. 0.1 g of polytetrafluoroethylene powder and 100 g of aqueous polyurethane acrylate emulsion were added, and the mixture was ground and dispersed using a ball mill for 6 hours. Finally, 2 g of polysiloxane defoamer and 3 g of polyvinyl alcohol leveling agent were added respectively, and the mixture was stirred and dispersed at 1000 rpm in a high-speed stirrer for 10 min to obtain a waterborne polyurethane acrylate wear-resistant and anti-corrosion coating.

[0036] The coating prepared in Example 3 has an adhesion of 0 and a hardness of 3H. The salt spray resistance test shows that after the coating is immersed for 500 h, the coating does not produce corrosion products and rust. The electrochemical test results show that the corrosion potential of the coating is -0.526 mV and the corrosion current is 1.88×10 -7 nA / cm 2 , the corrosion efficiency is 0.004 mm / a.

[0037] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the amount of modified graphene and polytetrafluoroethylene powder added in step (4) is 0. The adhesion of the coating prepared in Comparative Example 1 is level 0 and the hardness is 2H. The salt spray resistance test shows that after the coating is immersed for 500 h, corrosion products and rust are generated in the coating. The electrochemical test results show that the corrosion potential of the coating is -0.833 mV and the corrosion current is 2.55×10 -6 nA / cm 2 , the corrosion efficiency is 0.021 mm / a.

[0038] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the amount of modified graphene added in step (3) is 0. The coating prepared in Comparative Example 2 has an adhesion of level 0 and a hardness of 2H. The salt spray resistance test shows that after the coating is immersed for 500 h, corrosion products and rust are generated in the coating. The electrochemical test results show that the corrosion potential of the coating is -0.822 mV and the corrosion current is 2.66×10 -7 nA / cm 2 , the corrosion efficiency is 0.020 mm / a.

[0039] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that the amount of polytetrafluoroethylene added in step (3) is 0. The adhesion of the coating prepared in Comparative Example 3 is level 0 and the hardness is 3H. The salt spray resistance test shows that after the coating is immersed for 500 hours, the coating produces no corrosion products and rust. The electrochemical test results show that the corrosion potential of the coating is -0.651 mV and the corrosion current is 1.03×10 -6 nA / cm 2 , the corrosion efficiency is 0.011 mm / a.

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

Claims

1. A method for preparing a waterborne polyurethane acrylate wear-resistant and anti-corrosion coating, characterized in that: The steps include: A waterborne polyurethane acrylate emulsion and modified graphene are prepared respectively; The modified graphene and sodium dodecylbenzene sulfonate are dispersed in an ethanol solution with a mass concentration of 5%. After uniform dispersion, polytetrafluoroethylene powder and the aqueous polyurethane acrylate emulsion are added. After grinding and dispersion, a defoamer and a leveling agent are added. Finally, the mixture is dispersed by high-speed stirring to obtain an aqueous polyurethane acrylate wear-resistant and anti-corrosion coating.

2. The method for preparing the waterborne polyurethane acrylate wear-resistant and anticorrosive coating according to claim 1, characterized in that: The preparation method of the aqueous polyurethane acrylate emulsion is: After isophorone diisocyanate, modified palm oil and pentaerythritol triacrylate are mixed, dibutyltin dilaurate is added dropwise, and the mixture is reacted at 55-60°C to obtain a precursor; Add dihydroxymethylpropionic acid to the precursor, react at 55-60° C., cool to room temperature, add triethylamine, stir at 300-500 rpm, add deionized water, stir at 800-1200 rpm to obtain an aqueous polyurethane acrylate emulsion.

3. The method for preparing the waterborne polyurethane acrylate wear-resistant and anticorrosive coating according to claim 2, characterized in that: The mass ratio of isophorone diisocyanate to modified palm oil is (4-8):(5-10).

4. The method for preparing the waterborne polyurethane acrylate wear-resistant and anticorrosive coating according to claim 2 or 3, characterized in that: The preparation method of the modified palm oil is: Palm oil, diethanolamine and sodium methoxide are mixed and reacted at 140-160°C under the protection of nitrogen, then cooled to room temperature, saturated brine is added, shaken and allowed to stand, and extracted with carbon tetrachloride to obtain modified palm oil.

5. The method for preparing the waterborne polyurethane acrylate wear-resistant and anticorrosive coating according to claim 4, characterized in that: The mass ratio of palm oil to diethanolamine is (2-5):(1-2).

6. The method for preparing the waterborne polyurethane acrylate wear-resistant and anticorrosive coating according to claim 1, characterized in that: The preparation method of the modified graphene is: Graphene was dispersed in acetone, and isophorone diisocyanate and dibutyltin dilaurate were added. Under the protection of nitrogen, the reaction was carried out at 80-85°C, and then the temperature was lowered to 60-70°C, and then the reaction mixture was added. N,N -dimethylethanolamine, after continuing the reaction, the product is washed with acetone and deionized water, and finally freeze-dried to obtain modified graphene.

7. The method for preparing the waterborne polyurethane acrylate wear-resistant and anticorrosive coating according to claim 1, characterized in that: The rotation speed of the high-speed stirring is 1000 rpm.

8. The method for preparing the waterborne polyurethane acrylate wear-resistant and anticorrosive coating according to claim 1, characterized in that: The defoamer is selected from polysiloxane defoamers, and the leveling agent is selected from polyvinyl alcohol leveling agents.

9. Use of the waterborne polyurethane acrylate wear-resistant and anti-corrosion coating obtained by the preparation method according to claim 1 in metal wear-resistant and anti-corrosion.

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