An acrylic polyurethane coating containing modified graphene and a method for preparing the same

Abstract

The application discloses a kind of acrylic polyurethane coatings containing modified graphene and preparation method thereof, belong to water-based paint technical field, by the amino group in the anti-aging component p-aminodiphenylamine attack epoxy group in modified butadiene styrene rubber latex, make it ring-opening, promote anti-aging component graft in modified butadiene styrene rubber latex structure, improve the heat aging resistance of butadiene styrene rubber;Modified butadiene styrene rubber latex shrinks under irradiation and vulcanization, forms rubber nanoparticles, and contains double bond group in structure, can be broken under irradiation with graphene oxide and trimethylolpropane triacrylate, crosslinking polymerization, make rubber nanoparticles intercalate in graphene oxide sheet layer, rubber nanoparticles can be toughened as phase and cooperate with the sheet layer of graphene oxide, through slip dispersion stress, improve the mechanical strength of coating.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of water-based paint, and particularly relates to an acrylic polyurethane paint containing modified graphene and a preparation method thereof. BACKGROUND

[0002] Paints can be divided into oil-based and water-based paints according to the types of solvents. Oil-based paint is currently mainly used in China, which uses various organic solvents as dispersion and dilution media. Organic substances volatilize during use and cause air pollution. In recent years, people have realized that harmful substances such as formaldehyde emitted by oil-based paint may be an important inducement for cancer, and therefore the research on water-based paint has also become increasingly popular. Compared with traditional solvent-based oil-based paint, water-based paint has very outstanding environmental protection advantages, which uses water as a dispersion medium to avoid or reduce the use of organic solvents in traditional oil-based paint. With further development of science and technology, water-based paint is expected to become the mainstream of the global paint industry.

[0003] Graphene has unique geometric shape and novel physical properties: ultra-high specific surface area, excellent mechanical properties, high aspect ratio, high electron mobility, high thermal conductivity and excellent barrier properties, and raw materials are economically and easily available. In the field of paint, a small amount of graphene is often added to improve the corrosion resistance, wear resistance and electrical conductivity of paint, but there is a large van der Waals force and p-p stacking between graphene nanosheets, which can easily cause stacking and agglomeration, not only leading to the failure of the excellent performance of graphene, but also causing the deterioration of material performance, limiting its application, which is more obvious in water-based paint.

[0004] A Chinese patent with publication number CN112175509B discloses a graphene-reinforced acrylic polyurethane water-based paint and a preparation method thereof. In the scheme, butadiene styrene rubber nanoparticles are intercalated in graphene oxide, and the rubber nanoparticles can better improve the dispersion degree between nanometer graphene. With the high aspect ratio of graphene oxide, the impact force can be uniformly transmitted to the rubber nanoparticles, so that the impact resistance of the paint film can be significantly improved. However, butadiene styrene rubber is prone to thermal oxidative aging, which affects the service life of the paint film, and thus cannot effectively play the role of improving the impact resistance. SUMMARY

[0005] The present application aims to provide an acrylic polyurethane paint containing modified graphene and a preparation method thereof. The amino group in the anti-aging component p-aminodiphenylamine attacks the epoxy group in the modified butadiene styrene rubber latex to cause ring opening, so that the anti-aging component is grafted into the structure of the modified butadiene styrene rubber latex, thereby improving the thermal aging resistance of butadiene styrene rubber.

[0006] The object of the present application can be achieved by the following technical solutions:

[0007] A preparation method of an acrylic polyurethane coating containing modified graphene, comprising the following steps:

[0008] Step one: using liquid polybutadiene and p-aminostyrene as raw materials, glycidyl methacrylate as a third functional monomer, a modified butadiene styrene rubber latex is obtained by free radical copolymerization.

[0009] Step two: using the modified butadiene styrene rubber latex and p-aminodiphenylamine as raw materials, an antioxidant modified butadiene styrene rubber latex is prepared by amino ring-opening epoxy reaction.

[0010] Step three: under irradiation, the antioxidant modified butadiene styrene rubber latex is vulcanized and shrunk to form rubber nanoparticles, and the residual double bonds in the structure can be broken under irradiation and cross-linked to obtain intercalated modified graphene.

[0011] Step four: using the hydroxyl group of titanium dioxide powder and the isocyanate group at one end of isophorone diisocyanate to graft, and then using the isocyanate group at the other end to react with the hydroxyl group of hydroxyethyl methacrylate, a vinyl-modified titanium dioxide powder is obtained.

[0012] Step five: by reacting the hydroxyl groups of intercalated modified graphene, hydroxyethyl methacrylate, and butyl acrylate with diphenyl methane diisocyanate to form an acrylic grafted polyurethane copolymer, and then copolymerizing with the vinyl-modified titanium dioxide powder under an initiator, an acrylic polyurethane coating containing modified graphene is obtained.

[0013] Further, the specific preparation steps of the modified butadiene styrene rubber latex are as follows:

[0014] The pre-emulsion is placed in a reaction kettle and stirred at 30-40°C and 400-500r / min for 10-12min, then potassium persulfate is added, and the reaction is continued for 1-2h, then glycidyl methacrylate is added, and the reaction is continued for 1-2h, and then cooled to room temperature naturally to obtain the modified butadiene styrene rubber latex.

[0015] Further, the amount ratio of the pre-emulsion, potassium persulfate and glycidyl methacrylate is 90-92mL:0.4-0.8g:1.2-2.5g.

[0016] Further, the specific preparation steps of the pre-emulsion are as follows:

[0017] The liquid polybutadiene, p-aminostyrene, alkylphenol polyoxyethylene ether and sodium dodecyl sulfate are added into the reaction kettle, stirred at 50-60℃ and 400-500r / min for 20-30min, then 10-15% sodium phosphate solution is added to adjust the pH value to 8-10, continue to stir for 30-40min, the product is placed in ice water at 0-4℃, ultrasonic dispersion for 30-40min, to get the pre-emulsion.

[0018] Further, the amount of liquid polybutadiene, p-aminostyrene, alkylphenol polyoxyethylene ether, sodium dodecyl sulfate and sodium phosphate solution is 80-100g: 20-25g: 1.5-2g: 0.8-1.2g: 10-15mL.

[0019] Further, the specific preparation steps of the anti-aging modified butadiene rubber latex are as follows:

[0020] The p-aminodiphenylamine and modified butadiene rubber latex are added into the reaction kettle according to the amount ratio of 50-60g: 100-120mL, stirred at 50-60℃ and 400-500r / min for 20-30min, then continue to stir for 2-3h under nitrogen atmosphere, and naturally cooled to room temperature to obtain the anti-aging modified butadiene rubber latex.

[0021] Further, the specific preparation steps of the intercalation modified graphene are as follows:

[0022] The anti-aging modified butadiene rubber latex, graphene oxide and trimethylolpropane triacrylate are mixed by stirring according to the mass ratio of 40-42: 20-22: 3-3.2, then irradiated at a dose of 10-12kGy for 12-14h, filtered, and vacuum dried at 40-45℃ for 1-2h to obtain the intercalation modified graphene.

[0023] Further, the specific preparation steps of the vinyl modified titanium dioxide powder are as follows:

[0024] The modified titanium dioxide powder, dimethyl sulfoxide and hydroxyethyl methacrylate are added into the reaction kettle, stirred at 50-60℃ and 400-500r / min for 20-30min, then dibutyltin dilaurate is added, continue to stir for 10-12h under nitrogen atmosphere, filter, wash the product with dimethyl sulfoxide and acetone for 2-4 times respectively, and vacuum dried at 40-45℃ for 10-12h to obtain the vinyl modified titanium dioxide powder.

[0025] Further, the amount of modified titanium dioxide powder, dimethyl sulfoxide, hydroxyethyl methacrylate and dibutyltin dilaurate is 70-80g: 1-2L: 10-12g: 2.1-2.5g.

[0026] Further, the modified titanium dioxide powder is prepared according to the following steps:

[0027] The titanium dioxide powder and dimethyl sulfoxide are added into a reaction kettle, stirred at 50-60℃ and 400-500r / min for 20-30min, then isophorone diisocyanate and dibutyl tin dilaurate are added, the reaction is continued under nitrogen atmosphere for 10-12h, then hydroxyethyl methacrylate is added, heated to 70-80℃, the reaction is continued for 10-12h, filtered, the product is washed with dimethyl sulfoxide and acetone for 2-4 times, vacuum dried at 40-45℃ for 10-12h, to obtain the modified titanium dioxide powder. Further, the amount ratio of titanium dioxide powder, dimethyl sulfoxide, isophorone diisocyanate, dibutyl tin dilaurate and hydroxyethyl methacrylate is 100-120g:1-2L:100-120g:2.1-2.5g:10-12g. Further, the acrylic polyurethane coating containing modified graphene is prepared according to the following steps:

[0028] The intercalated modified graphene, hydroxyethyl methacrylate, butyl acrylate, vinyl modified titanium dioxide powder and deionized water are added into a reaction kettle, stirred at 40-45℃ and 400-500r / min for 20-30min, then diphenyl methane diisocyanate and dibutyl tin dilaurate are added, the reaction is continued for 2-3h, to form an acrylic grafted polyurethane copolymer, then dibenzoyl peroxide is added, heated to 60-70℃, the reaction is continued for 2-3h, filtered, the product is washed with deionized water for 2-3 times, vacuum dried at 60-80℃ for 1-2h, to obtain an acrylic polyurethane coating containing modified graphene.

[0029] Further, the amount ratio of intercalated modified graphene, hydroxyethyl methacrylate, butyl acrylate, vinyl modified titanium dioxide powder, deionized water, diphenyl methane diisocyanate, dibutyl tin dilaurate and dibenzoyl peroxide is 30-32g:80-90g:30-40g:7-8g:200-220mL:30-40g:2.3-2.5g:0.1-0.2g.

[0030] The beneficial effects of the present application are:

[0031] 1. The acrylic polyurethane coating containing modified graphene prepared by the present application has good heat and oxygen aging resistance and ultraviolet resistance, can improve the weather resistance of the coating, and prolong the service life of the coating when used outdoors.

[0032] 2.The modified graphene-containing acrylic polyurethane coating of the present application, by attacking the epoxy group in the modified styrene-butadiene rubber latex with the amino group in the antioxidant component p-aminodiphenylamine to open the ring, the antioxidant component is grafted in the structure of the modified styrene-butadiene rubber latex, and the heat aging resistance of the styrene-butadiene rubber is improved; the modified styrene-butadiene rubber latex shrinks and vulcanizes under irradiation to form rubber nanoparticles, and the structure contains double bond groups, which can be broken and cross-linked under irradiation with graphene oxide and trimethylolpropane triacrylate, so that the rubber nanoparticles are intercalated in the graphene oxide sheet layer, and the rubber nanoparticles can cooperate with the sheet layer of graphene oxide as a toughening phase to disperse stress by sliding and improve the mechanical strength of the coating.

[0033] 3.When the rubber nanoparticles formed by the modified styrene-butadiene rubber intercalate the graphene oxide, the space structure between the sheet layers can fix the antioxidant component, avoiding the traditional antioxidant that is prone to migrate from the inside of the base material to the surface of the rubber product during the use of the rubber material, thereby avoiding reducing the antioxidant effect of the coating; the main components of p-aminodiphenylamine antioxidant are amino and imino, and the amino and imino are positively charged in the solution, while the sheet layer of graphene oxide is negatively charged, so that the antioxidant component can guide the intercalation process through electrostatic interaction during the intercalation of the graphene oxide sheet layer.

[0034] 4.The vinyl-modified titanium dioxide powder of the present application can impart excellent ultraviolet resistance to the coating, and by modifying the double bond of titanium dioxide, polymerization sites can exist on the surface of titanium dioxide, which can be fixed in the polymerization network of the modified graphene-containing acrylic polyurethane coating through free radical polymerization, avoiding agglomeration and making the ultraviolet resistance stable; and the polymerization can make titanium dioxide fill the micropores and microcracks generated during the curing process of the coating, avoiding providing a penetration channel for corrosive media, and further prolonging the service life of the coating. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0036] Embodiment 1: A preparation method of a modified graphene-containing acrylic polyurethane coating, comprising the following steps:

[0037] S1: 80 g of liquid polybutadiene, 20 g of p-aminostyrene, 1.5 g of alkyl phenol polyoxyethylene ether and 0.8 g of sodium dodecyl sulfate were added into a reaction kettle, stirred at 50℃ and 400 r / min for 20 min, then 10 mL of 10% mass fraction of trisodium phosphate solution was added, the pH value was adjusted to 8, and the stirring was continued for 30 min, the product was placed in ice water at 0℃, and ultrasonic dispersion was carried out for 30 min to obtain a pre-emulsion; 90 mL of the pre-emulsion was placed in a reaction kettle, stirred at 30℃ and 400 r / min for 10 min, then 0.4 g of potassium persulfate was added, and the stirring reaction was continued for 1 h, then 1.2 g of glycidyl methacrylate was added, and the stirring reaction was continued for 1 h, and then the temperature was naturally cooled to room temperature to obtain a modified butadiene-styrene rubber latex.

[0038] S2: 50 g of p-aminodiphenylamine and 100 mL of the modified butadiene-styrene rubber latex were added into a reaction kettle, stirred at 50℃ and 400 r / min for 20 min, then the stirring was continued for 2 h under a nitrogen atmosphere, and the temperature was naturally cooled to room temperature to obtain an antioxidant modified butadiene-styrene rubber latex.

[0039] S3: 40 g of the antioxidant modified butadiene-styrene rubber latex, 20 g of graphene oxide and 3 g of trimethylolpropane triacrylate were stirred and mixed, then irradiated at a radiation dose of 10 kGy for 12 h, filtered, and vacuum dried at 40℃ for 1 h to obtain an intercalated modified graphene.

[0040] S4: 100 g of titanium dioxide powder and 1 L of dimethyl sulfoxide were added into a reaction kettle, stirred at 50℃ and 400 r / min for 20 min, then 100 g of isophorone diisocyanate and 2.1 g of dibutyltin dilaurate were added, the stirring reaction was continued for 10 h under a nitrogen atmosphere, filtered, and the product was washed with dimethyl sulfoxide and acetone for 2 times respectively, and vacuum dried at 40℃ for 10 h to obtain a modified titanium dioxide powder; 70 g of the modified titanium dioxide powder, 1 L of dimethyl sulfoxide and 10 g of hydroxyethyl methacrylate were added into a reaction kettle, stirred at 50℃ and 400 r / min for 20 min, then 2.1 g of dibutyltin dilaurate was added, the stirring reaction was continued for 10 h under a nitrogen atmosphere, filtered, and the product was washed with dimethyl sulfoxide and acetone for 2 times respectively, and vacuum dried at 40℃ for 10 h to obtain a vinyl modified titanium dioxide powder.

[0041] S5: 30 g of intercalated modified graphene, 80 g of hydroxyethyl methacrylate, 30 g of butyl acrylate, 7 g of vinyl modified titanium dioxide powder and 200 mL of deionized water were added to a reaction kettle, stirred at 40°C and 400 r / min for 20 min, then 30 g of diphenyl methane diisocyanate and 2.3 g of dibutyl tin dilaurate were added, and the reaction was continued for 2 h to form an acrylic grafted polyurethane copolymer, then 0.1 g of dibenzoyl peroxide was added, heated to 60°C, and the reaction was continued for 2 h. The product was filtered, washed with deionized water twice, and vacuum dried at 60°C for 1 h to obtain an acrylic polyurethane coating containing modified graphene.

[0042] Example 2: A method for preparing an acrylic polyurethane coating containing modified graphene, comprising the following steps:

[0043] S1: 90 g of liquid polybutadiene, 22.5 g of p-aminostyrene, 1.75 g of alkyl phenol polyoxyethylene ether and 1.0 g of sodium dodecyl sulfate were added to a reaction kettle, stirred at 55°C and 450 r / min for 25 min, then 12.5 mL of 12.5% mass fraction of trisodium phosphate solution was added to adjust the pH value to 9, and the stirring was continued for 35 min. The product was placed in ice water at 2°C and ultrasonically dispersed for 35 min to obtain a pre-emulsion; 91 mL of the pre-emulsion was placed in a reaction kettle, stirred at 35°C and 450 r / min for 11 min, then 0.6 g of potassium persulfate was added, and the reaction was continued for 1.5 h, then 1.85 g of glycidyl methacrylate was added, and the reaction was continued for 1.5 h, and then naturally cooled to room temperature to obtain a modified butadiene-styrene rubber latex.

[0044] S2: 55 g of p-aminodiphenylamine and 110 mL of modified butadiene-styrene rubber latex were added to a reaction kettle, stirred at 55°C and 450 r / min for 25 min, then stirred for 2.5 h under a nitrogen atmosphere, and naturally cooled to room temperature to obtain an antioxidant modified butadiene-styrene rubber latex.

[0045] S3: 41 g of antioxidant modified butadiene-styrene rubber latex, 21 g of oxidized graphene and 3.1 g of trimethylolpropane triacrylate were stirred and mixed, then irradiated at a radiation dose of 11 kGy for 13 h, filtered, and vacuum dried at 42.5°C for 1.5 h to obtain intercalated modified graphene.

[0046] S4: 110 g of titanium dioxide powder and 1.5 L of dimethyl sulfoxide were added into a reaction kettle, stirred at 55°C and 450 r / min for 25 min, then 110 g of isophorone diisocyanate and 2.3 g of dibutyltin dilaurate were added, the reaction was continued under nitrogen atmosphere for 11 h, the product was filtered, washed with dimethyl sulfoxide and acetone for 3 times respectively, vacuum dried at 42.5°C for 11 h, to obtain modified titanium dioxide powder; 75 g of modified titanium dioxide powder, 1.5 L of dimethyl sulfoxide and 11 g of hydroxyethyl methacrylate were added into a reaction kettle, stirred at 55°C and 450 r / min for 25 min, then 2.3 g of dibutyltin dilaurate was added, the reaction was continued under nitrogen atmosphere for 11 h, the product was filtered, washed with dimethyl sulfoxide and acetone for 3 times respectively, vacuum dried at 42.5°C for 11 h, to obtain vinyl modified titanium dioxide powder.

[0047] S5: 31 g of intercalated modified graphene, 85 g of hydroxyethyl methacrylate, 35 g of butyl acrylate, 7.5 g of vinyl modified titanium dioxide powder and 210 mL of deionized water were added into a reaction kettle, stirred at 42.5°C and 450 r / min for 25 min, then 35 g of diphenylmethane diisocyanate and 2.4 g of dibutyltin dilaurate were added, the reaction was continued for 2.5 h, to form an acrylic acid grafted polyurethane copolymer, then 0.15 g of dibenzoyl peroxide was added, heated to 65°C, the reaction was continued for 2.5 h, the product was filtered, washed with deionized water for 2.5 times, vacuum dried at 70°C for 1.5 h, to obtain an acrylic polyurethane coating containing modified graphene.

[0048] Example 3: A preparation method of an acrylic polyurethane coating containing modified graphene, comprising the following steps:

[0049] S1: 100 g of liquid polybutadiene, 25 g of p-aminostyrene, 2 g of alkyl phenol polyoxyethylene ether and 1.2 g of sodium dodecyl sulfate were added into a reaction kettle, stirred at 60°C and 500 r / min for 30 min, then 15 mL of 15% trisodium phosphate solution was added, the pH value was adjusted to 10, the stirring was continued for 40 min, the product was placed in ice water at 4°C, and ultrasonic dispersion was performed for 40 min, to obtain a pre-emulsion; 92 mL of the pre-emulsion was placed in a reaction kettle, stirred at 40°C and 500 r / min for 12 min, then 0.8 g of potassium persulfate was added, the reaction was continued for 2 h, then 2.5 g of glycidyl methacrylate was added, the reaction was continued for 2 h, and the temperature was naturally cooled to room temperature, to obtain a modified butadiene-styrene rubber latex.

[0050] S2: 60 g of p-aminodiphenylamine and 120 mL of modified butadiene styrene rubber latex were added into a reaction kettle, stirred at 60 °C and 500 r / min for 30 min, then continued to stir for 3 h under nitrogen atmosphere, naturally cooled to room temperature, to obtain anti-aging modified butadiene styrene rubber latex.

[0051] S3: 42 g of anti-aging modified butadiene styrene rubber latex, 22 g of graphene oxide and 3.2 g of trimethylolpropane triacrylate were stirred and mixed, then irradiated at a radiation dose of 12 kGy for 14 h, filtered, vacuum dried at 45 °C for 2 h, to obtain intercalated modified graphene.

[0052] S4: 120 g of titanium dioxide powder and 2 L of dimethyl sulfoxide were added into a reaction kettle, stirred at 60 °C and 500 r / min for 30 min, then 120 g of isophorone diisocyanate and 2.5 g of dibutyltin dilaurate were added, continued to stir for 12 h under nitrogen atmosphere, filtered, the product was washed with dimethyl sulfoxide and acetone for 4 times respectively, vacuum dried at 45 °C for 12 h, to obtain modified titanium dioxide powder; 80 g of modified titanium dioxide powder, 2 L of dimethyl sulfoxide and 12 g of hydroxyethyl methacrylate were added into a reaction kettle, stirred at 60 °C and 500 r / min for 30 min, then 2.5 g of dibutyltin dilaurate was added, continued to stir for 12 h under nitrogen atmosphere, filtered, the product was washed with dimethyl sulfoxide and acetone for 4 times respectively, vacuum dried at 45 °C for 12 h, to obtain vinyl modified titanium dioxide powder.

[0053] S5: 32 g of intercalated modified graphene, 90 g of hydroxyethyl methacrylate, 40 g of butyl acrylate, 8 g of vinyl modified titanium dioxide powder and 220 mL of deionized water were added into a reaction kettle, stirred at 45 °C and 500 r / min for 30 min, then 40 g of diphenylmethane diisocyanate and 2.5 g of dibutyltin dilaurate were added, continued to react for 3 h, to form an acrylic grafted polyurethane copolymer, then 0.2 g of dibenzoyl peroxide was added, heated to 70 °C, continued to react for 3 h, filtered, the product was washed with deionized water for 3 times, vacuum dried at 80 °C for 2 h, to obtain an acrylic polyurethane coating containing modified graphene.

[0054] Comparative Example 1: on the basis of Example 3, the anti-aging modified butadiene styrene rubber latex in step S3 was replaced by the modified butadiene styrene rubber latex prepared in step S1, and the remaining steps were unchanged, to prepare an acrylic polyurethane coating containing modified graphene.

[0055] Comparative Example 2: on the basis of Example 3, the modified butadiene styrene rubber latex in step S2 was replaced by commercially available LIPATON SB 60B11 butadiene styrene rubber latex of Xiteka, and the remaining steps were unchanged, to prepare an acrylic polyurethane coating containing modified graphene.

[0056] Comparative Example 3: On the basis of Example 3, the vinyl-modified titanium dioxide powder in step S4 was replaced by the raw material in step S4, and the remaining steps were unchanged, to prepare a modified graphene-containing acrylic polyurethane coating.

[0057] The modified graphene-containing acrylic polyurethane coatings prepared in Examples 1-3 and Comparative Examples 1-3 were tested for performance. The modified graphene-containing acrylic polyurethane coatings were coated on tinplate, dried and cured by heating, and samples of the corresponding specifications were prepared according to different test standards. The adhesion of different samples was tested according to GB / T 1720-2020 (0-5 grade, with 0 grade being the best performance). The initial flexibility of different samples was tested according to GB / T 1731-2020, and the smaller the result, the better the flexibility of the paint film. The impact resistance of different samples was tested according to GB / T 1732-2020, and the larger the result, the better the impact resistance of the paint film.

[0058] The heat aging test was carried out in a 401-A type hot air aging oven under the circulation of hot air in a 100℃ oven. The ultraviolet aging test was carried out in an ultraviolet light accelerated aging tester at a temperature of 25℃ and a humidity of 50% for 720h, and then the flexibility and impact resistance were tested.

[0059] Table 1: Performance test results of modified graphene-containing acrylic polyurethane coatings

[0060]

[0061] As can be seen from Table 1, the adhesion, flexibility and impact resistance of the modified graphene-containing acrylic polyurethane coatings prepared in Examples 1-3 are significantly better than those of the comparative examples, indicating that the modified graphene-containing acrylic polyurethane coatings prepared by the present application have good heat and oxygen aging resistance and ultraviolet resistance, and have a good service life when used outdoors.

[0062] In Comparative Example 1, the anti-aging modified styrene-butadiene rubber latex in step S3 was replaced by the modified styrene-butadiene rubber latex prepared in step S1. The anti-aging component was prone to migration, and the amino group of p-aminodiphenylamine was not grafted with the epoxy group. The anti-aging component could not be fixed in the graphene oxide layer by electrostatic action, and was prone to migrate from the coating matrix to the surface during use, resulting in significant deterioration of flexibility and impact resistance after heat and ultraviolet aging. The free radical capture effect of p-aminodiphenylamine was lacking, the coating aged rapidly in a heat and oxygen environment, the mechanical properties and structural stability decreased rapidly, and the long-term outdoor use requirement could not be met.

[0063] Comparative Example 2 replaces the modified styrene butadiene rubber latex in step S3 with a commercially available styrene butadiene rubber latex, which is not grafted with epoxy groups and cannot be grafted with the antioxidant component p-aminodiphenylamine, resulting in physical mixing of the antioxidant component and the styrene butadiene rubber latex, and migration of the antioxidant component.

[0064] Comparative Example 3 replaces the vinyl-modified titanium dioxide powder in step S4 with a raw material in step S4, which is not stable against ultraviolet rays and has not been modified by double bond modification, has no polymerization sites on the surface, and is easily agglomerated and cannot be stably fixed in the coating polymer network, resulting in a significant decrease in ultraviolet resistance, a serious decrease in flexibility and impact resistance after ultraviolet aging, and a possible failure of the unmodified titanium dioxide to fill the coating curing micropores by polymerization, penetration of corrosive media, and accelerated aging of the coating, leading to a significant decrease in performance after heat and ultraviolet aging.

[0065] Although embodiments of the present application have been shown and described, it is to be understood that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present application.

Claims

1. A method for preparing an acrylic polyurethane coating containing modified graphene, characterized in that, Includes the following steps: Step 1: Using liquid polybutadiene and p-aminostyrene as raw materials, and glycidyl methacrylate as the third functional monomer, modified styrene-butadiene rubber latex is obtained through free radical copolymerization. Step 2: Using modified styrene-butadiene rubber latex and p-aminodiphenylamine as raw materials, an anti-aging modified styrene-butadiene rubber latex is prepared through an amino ring-opening epoxy reaction; Step 3: Under irradiation, the anti-aging modified styrene-butadiene rubber latex vulcanizes and shrinks to form rubber nanoparticles. The double bonds remaining in the structure can break with the epoxy groups of graphene oxide and the double bonds of trimethylolpropane triacrylate under irradiation, crosslinking and polymerizing to obtain intercalated modified graphene. Step 4: The hydroxyl groups of titanium dioxide powder are grafted onto one end of the isocyanate group of isophorone diisocyanate, and then the other end of the isocyanate group is reacted with the hydroxyl groups of hydroxyethyl methacrylate to obtain vinyl-modified titanium dioxide powder. Step 5: The hydroxyl groups of intercalated modified graphene, hydroxyethyl methacrylate, and butyl acrylate react with diphenylmethane diisocyanate to form an acrylic grafted polyurethane copolymer, which is then copolymerized with vinyl-modified titanium dioxide powder under an initiator to obtain an acrylic polyurethane coating containing modified graphene. The specific preparation steps for intercalated modified graphene are as follows: Anti-aging modified styrene-butadiene rubber latex, graphene oxide, and trimethylolpropane triacrylate were mixed in a mass ratio of 40-42:20-22:3-3.2, then irradiated at an irradiation dose of 10-12 kGy for 12-14 h, filtered, and vacuum dried at 40-45℃ for 1-2 h to obtain intercalated modified graphene. The specific preparation steps of the modified styrene-butadiene rubber latex are as follows: The pre-emulsion was placed in a reaction vessel and stirred at 30-40℃ and 400-500r / min for 10-12min. Potassium persulfate was added and the reaction was continued to be stirred for 1-2h. Then glycidyl methacrylate was added and the reaction was continued to be stirred for 1-2h. The mixture was then naturally cooled to room temperature to obtain modified styrene-butadiene rubber latex. The specific preparation steps of the pre-emulsion are as follows: Liquid polybutadiene, p-aminostyrene, alkylphenol polyoxyethylene ether, and sodium dodecyl sulfate were added to a reaction vessel and stirred at 50-60℃ and 400-500 r / min for 20-30 min. Then, 10-15 wt% trisodium phosphate solution was added to adjust the pH to 8-10, and stirring was continued for 30-40 min. The product was then placed in ice water at 0-4℃ and ultrasonically dispersed for 30-40 min to obtain a pre-emulsion. The specific preparation steps for the vinyl-modified titanium dioxide powder are as follows: Modified titanium dioxide powder, dimethyl sulfoxide, and hydroxyethyl methacrylate were added to a reaction vessel and stirred for 20-30 min at 50-60℃ and 400-500 r / min. Then, dibutyltin dilaurate was added, and the reaction was continued to be stirred for 10-12 h under a nitrogen atmosphere. The mixture was filtered, and the product was washed 2-4 times with dimethyl sulfoxide and acetone, respectively. The product was then vacuum dried at 40-45℃ for 10-12 h to obtain vinyl-modified titanium dioxide powder. The specific preparation steps of the modified titanium dioxide powder are as follows: Titanium dioxide powder and dimethyl sulfoxide were added to a reaction vessel and stirred at 50-60℃ and 400-500 r / min for 20-30 min. Then, isophorone diisocyanate and dibutyltin dilaurate were added, and the reaction was continued to be stirred for 10-12 h under a nitrogen atmosphere. Then, hydroxyethyl methacrylate was added, heated to 70-80℃, and the reaction was continued to be stirred for 10-12 h. The mixture was filtered, washed, and vacuum dried to obtain modified titanium dioxide powder.

2. The method for preparing an acrylic polyurethane coating containing modified graphene according to claim 1, characterized in that, The ratio of the preemulsion, potassium persulfate, and glycidyl methacrylate is 90-92 mL: 0.4-0.8 g: 1.2-2.5 g.

3. The method for preparing an acrylic polyurethane coating containing modified graphene according to claim 1, characterized in that, The ratio of the liquid polybutadiene, p-aminostyrene, alkylphenol polyoxyethylene ether, sodium dodecyl sulfate, and trisodium phosphate solution is 80-100g: 20-25g: 1.5-2g: 0.8-1.2g: 10-15mL.

4. The method for preparing an acrylic polyurethane coating containing modified graphene according to claim 1, characterized in that, The specific preparation steps for the anti-aging modified styrene-butadiene rubber latex are as follows: Add p-aminodiphenylamine and modified styrene-butadiene rubber latex to a reaction vessel at a ratio of 50-60g:100-120mL, stir at 50-60℃ and 400-500r / min for 20-30min, then continue stirring for 2-3h under a nitrogen atmosphere, and allow to cool naturally to room temperature to obtain anti-aging modified styrene-butadiene rubber latex.

5. The method for preparing an acrylic polyurethane coating containing modified graphene according to claim 1, characterized in that, The ratio of the modified titanium dioxide powder, dimethyl sulfoxide, hydroxyethyl methacrylate and dibutyltin dilaurate is 70-80g: 1-2L: 10-12g: 2.1-2.5g.

6. The method for preparing an acrylic polyurethane coating containing modified graphene according to claim 1, characterized in that, The ratio of titanium dioxide powder, dimethyl sulfoxide, isophorone diisocyanate, dibutyltin dilaurate, and hydroxyethyl methacrylate is 100-120g: 1-2L: 100-120g: 2.1-2.5g: 10-12g.

7. The method for preparing an acrylic polyurethane coating containing modified graphene according to claim 1, characterized in that, The specific preparation steps of the modified graphene-containing acrylic polyurethane coating are as follows: Intercalated graphene, hydroxyethyl methacrylate, butyl acrylate, vinyl-modified titanium dioxide powder, and deionized water were added to a reaction vessel and stirred at 40-45℃ and 400-500 rpm for 20-30 minutes. Then, diphenylmethane diisocyanate and dibutyltin dilaurate were added, and the reaction was continued for 2-3 hours to form an acrylic-grafted polyurethane copolymer. Benzoyl peroxide was then added, and the mixture was heated to 60-70℃ and reacted for another 2-3 hours. The mixture was filtered, and the product was washed 2-3 times with deionized water and dried under vacuum at 60-80℃ for 1-2 hours to obtain an acrylic polyurethane coating containing modified graphene.

8. The method for preparing an acrylic polyurethane coating containing modified graphene according to claim 7, characterized in that, The ratio of intercalated modified graphene, hydroxyethyl methacrylate, butyl acrylate, vinyl-modified titanium dioxide powder, deionized water, diphenylmethane diisocyanate, dibutyltin dilaurate, and benzoyl peroxide is 30-32g: 80-90g: 30-40g: 7-8g: 200-220mL: 30-40g: 2.3-2.5g: 0.1-0.2g.

9. An acrylic polyurethane coating containing modified graphene, characterized in that, It is prepared by the preparation method described in any one of claims 1-8.

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