Fluorine-containing acrylate / graphene modified polyurethane coating, and preparation method and application thereof

Abstract

The application discloses fluorine-containing acrylic ester / graphene modified polyurethane paint as well as a preparation method and application thereof, and belongs to the technical field of oil well pipe surface treatment in the petroleum and natural gas industry. The method disclosed by the application uses polypropylene glycol, dimethylol propionic acid and toluene diisocyanate to prepare polyurethane prepolymer, realizes modification of polyurethane by using a multiple modification method, and then mixes the polyurethane prepolymer, fluorine-containing acrylic ester / graphene dispersion liquid, ethylenediamine and triaminopropyl siloxane, and combines the fluorine-containing polymer with graphene in the form of a covalent bond under the action of a catalyst by using the active functional groups such as the hydroxyl groups on the surface and the edge of graphene, so that the mechanical properties, corrosion resistance and high-temperature aging resistance of the coating are improved, and the coating has wide application value and prospect.

Description

Technical Field

[0001] This invention belongs to the field of oil well pipe surface treatment technology in the oil and gas industry, specifically relating to a fluorinated acrylate / graphene modified polyurethane coating, its preparation method, and its application. Background Technology

[0002] As petroleum exploration and development deepens, the operating conditions of oil and gas wells become increasingly complex, highlighting tubing corrosion failure as a major challenge hindering the sustainable development of the petroleum industry. In the later stages of oil production, water injection technology is often used to improve efficiency. However, in water-injected environments, tubing faces challenges such as dissolved oxygen corrosion, bacterial corrosion, under-deposit corrosion, and corrosion from CO2 and Cl. - Corrosion problems caused by corrosive media such as H2S are a significant concern for oil and gas field production units, as are the impacts and economic losses resulting from corrosion failure. Among the various existing surface protection technologies, coating protection is the most economical and practical. However, with the increasingly harsh downhole environment, the presence of CO2, Cl... - With the increasing concentration of corrosive media such as H2S, existing polyurethane coatings are gradually becoming unable to meet the protection requirements against various corrosive media in downhole environments. Summary of the Invention

[0003] In order to overcome the shortcomings of the prior art, the present invention aims to provide a fluorinated acrylate / graphene modified polyurethane coating, its preparation method and application, to solve the problem that conventional polyurethane coatings cannot provide sufficient protection against tubing corrosion failure caused by the downhole environment of water injection wells.

[0004] To achieve the above objectives, the present invention employs the following technical solution:

[0005] This invention discloses a method for preparing a fluorinated acrylate / graphene modified polyurethane coating, comprising the following steps:

[0006] S1: Fluorinated acrylate copolymer, graphene and dichloromethane are mixed to obtain fluorinated acrylate / graphene dispersion;

[0007] S2: Polypropylene glycol and dimethylolpropionic acid are mixed and then subjected to vacuum dehydration to completely dissolve the dimethylolpropionic acid, resulting in a mixed solution; toluene diisocyanate is then added to the mixed solution, and after reaction, a polyurethane prepolymer is obtained.

[0008] S3: The polyurethane prepolymer and triethylamine are mixed and reacted to obtain mixed solution A; ethylenediamine and triaminopropylsiloxane are added to mixed solution A and reacted to obtain mixed solution B; fluorinated acrylate / graphene dispersion is added to mixed solution B and stirred and sheared to obtain fluorinated acrylate / graphene modified polyurethane coating.

[0009] Further, in S1, the preparation method of the fluorinated acrylate copolymer is as follows: styrene and tridecafluorooctyl methacrylate are mixed, washed until the washing liquid is neutral, then an initiator is added, and after heating and heat preservation treatment, a reaction product is obtained. The reaction product is then rinsed, precipitated, and dried to obtain the fluorinated acrylate copolymer.

[0010] Further, the ratio of styrene, tridecafluorooctyl methacrylate and initiator is (25-50)g:(15-30)g:(12-24)g; the heating to 70-80℃ and the holding time is 12-15h; the initiator is azobisisobutyronitrile.

[0011] Further, in S1, the ratio of the fluorinated acrylate copolymer, graphene, and dichloromethane is (18-22) g: (1.5-5) g: (50-100) mL; after mixing the fluorinated acrylate copolymer, graphene, and dichloromethane, the mixture is ultrasonically dispersed for 15-20 minutes to obtain a fluorinated acrylate / graphene dispersion.

[0012] Further, in S2, the ratio of polypropylene glycol, dimethylolpropionic acid, and toluene diisocyanate is (100-360)g:(100-360)g:(80-160)g; the vacuum dehydration treatment is carried out in a vacuum drying oven at 65℃-80℃ for 2-3 hours; after the temperature of the mixed solution drops to room temperature, toluene diisocyanate is added, and the reaction is carried out at 75℃-80℃ for 3-6 hours to obtain a polyurethane prepolymer.

[0013] Furthermore, in S3, the ratio of polyurethane prepolymer to triethylamine is (270–900) g: (12–30) g.

[0014] Further, in S3, the ratio of the amount of triethylamine, ethylenediamine and triaminopropylsiloxane is (12-30)g:(8-22)g:(15-30)g; the ratio of the amount of triaminopropylsiloxane and the fluorinated acrylate / graphene dispersion is (15-30)g:(85-160)g.

[0015] Further, in S3, the reaction time is 0.5h to 3h; the stirring is carried out at a stirring speed of 1800r / min to 2200r / min; and the shear emulsification time is 0.5h to 1.5h.

[0016] The present invention also discloses a fluorinated acrylate / graphene modified polyurethane coating prepared by the above preparation method.

[0017] The present invention also discloses the application of the above-mentioned fluorinated acrylate / graphene modified polyurethane coating, wherein the fluorinated acrylate / graphene modified polyurethane coating is used as a surface protective coating for water injection well tubing.

[0018] When the fluorinated acrylate / graphene modified polyurethane coating is used as a surface protective coating for water injection well tubing, the steps are as follows: First, adjust the viscosity of the fluorinated acrylate / graphene modified polyurethane coating to 85-95 kDa, then add pigments and fillers and mix evenly. Then, spray it onto the surface of the water injection well tubing. After curing at room temperature, a composite coating of fluorinated acrylate / graphene modified polyurethane is obtained on the surface of the water injection well tubing.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] This invention discloses a method for preparing fluorinated acrylate / graphene modified polyurethane coatings. A polyurethane prepolymer is prepared using polypropylene glycol, dimethylolpropionic acid, and toluene diisocyanate, achieving multi-modification of the polyurethane. Subsequently, the polyurethane prepolymer, a fluorinated acrylate / graphene dispersion, ethylenediamine, and triaminopropylsiloxane are mixed. Utilizing the active functional groups such as hydroxyl groups on the surface and edges of graphene under the action of a catalyst, the fluorinated polymer covalently bonds with the graphene. This bonding effectively reduces the surface energy of the graphene, minimizing spontaneous graphene aggregation. This invention effectively improves the hydrophobic properties of the modified coating. Furthermore, the cross-linking modification of the fluoropolymer and polyurethane enhances the coating's water resistance and heat resistance. Moreover, by utilizing graphene's large specific surface area and ultra-high density, the penetration path of corrosive media can be made more tortuous by filling defects in the prepolymer, thereby improving the coating's corrosion resistance. The layered distribution of graphene can form a mechanical interlock with the polyurethane; additionally, the groups on graphene can form chemical bonds with the polymer matrix, enhancing interfacial interactions and thus improving the system's mechanical properties. This invention is simple to operate, easy to industrialize, and has broad application prospects.

[0021] This invention also discloses a fluorinated acrylate / graphene modified polyurethane coating prepared by the above preparation method. The fluorinated acrylate / graphene modified polyurethane coating has strong corrosion resistance, water resistance and heat resistance. At the same time, since the groups on the graphene can form chemical bonds with the polymer matrix, the interfacial interaction is enhanced, thereby improving its mechanical properties and giving it broad application prospects.

[0022] This invention also discloses the application of fluorinated acrylate / graphene modified polyurethane coatings. When used as surface protective coatings for water injection well tubing, these coatings effectively prevent corrosion failure of the tubing surface, improving the coating's mechanical properties, corrosion resistance, and high-temperature aging resistance. Relevant experimental results demonstrate that the fluorinated acrylate / graphene modified polyurethane composite coating disclosed in this invention can withstand high-temperature and high-pressure performance tests at 150°C and 35MPa; it exhibits a contact angle of 94°, demonstrating good hydrophobic properties; and it retains good adhesion after being cut by a knife and torn by tape, demonstrating excellent protective coating performance. Attached Figure Description

[0023] Figure 1 This is the FTIR spectrum of the graphene of this invention. Detailed Implementation

[0024] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0025] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0026] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0027] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0028] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0029] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0030] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0031] Example 1

[0032] A method for preparing a fluorinated acrylate / graphene modified polyurethane coating includes the following steps:

[0033] S1: Add 25g of styrene (ST) and 15g of tridecyl fluorooctyl methacrylate (PFOMA) to a three-necked flask, wash thoroughly with 100mL of deionized water until the pH of the washing solution is neutral; then add 12g of azobisisobutyronitrile (AIBN), mix and stir evenly, then heat to 75℃ and keep warm for 12h to obtain the reaction product. The reaction product is repeatedly washed and precipitated with methanol, and finally dried in a constant temperature drying oven at 70℃ for 2h to obtain a fluorinated acrylate copolymer.

[0034] 20g of fluorinated acrylate copolymer and 1.5g of graphene (RGO) were dissolved in 50mL of dichloromethane, stirred evenly and ultrasonically dispersed for 15min to obtain fluorinated acrylate / graphene dispersion.

[0035] S2: Place 100g of polypropylene glycol (PPG-1000) and 100g of dimethylolpropionic acid (DMPA) into a beaker, place it in a vacuum drying oven at 70℃, and vacuum dry for 2 hours to perform vacuum dehydration treatment, so that the dimethylolpropionic acid is completely dissolved to obtain a mixed solution; after drying, remove the beaker, and after the beaker cools to room temperature, add 90g of toluene diisocyanate (TDI) to the mixed solution and keep it at 80℃ for 3 hours to obtain a polyurethane prepolymer; cool the polyurethane prepolymer to room temperature and add an appropriate amount of acetone to adjust the viscosity to 85ku;

[0036] S3: Mix 270g of polyurethane prepolymer and 15g of triethylamine (TEA) and neutralize for 0.5h to obtain mixed solution A; add 8g of ethylenediamine (EDA) and 15g of triaminopropylsiloxane (APTES) to mixed solution A and continue the reaction for 1h to obtain mixed solution B; add 89g of fluorinated acrylate / graphene dispersion to mixed solution B and stir at 2000r / min, and shear emulsify for 0.5h to obtain fluorinated acrylate / graphene modified polyurethane coating.

[0037] The Fourier transform infrared spectrum of the graphene used in Example 1 is as follows: Figure 1 As shown in the figure, GO values ​​are 3447, 1741, 1625, 1200, and 1120 cm. -1 The characteristic absorption bands at these locations correspond to -OH, C=O, C=C, CO, and COO, respectively. This indicates that a large number of oxygen-containing functional groups are distributed on the GO surface, while a small number of highly reactive carboxyl and carbonyl groups are distributed at the edge of the sheets. These active functional groups, under the action of a catalyst, enable better bonding between the fluoropolymer and graphene, effectively improving the performance of the modified coating.

[0038] The viscosity of the fluorinated acrylate / graphene-modified polyurethane coating prepared in Example 1 was adjusted to 90 kDa, and 180 g of pigments and fillers were added and mixed evenly. The mixture was then sprayed onto the surface of the water injection well tubing. After curing at room temperature, a composite coating of fluorinated acrylate / graphene-modified polyurethane was obtained on the surface of the water injection well tubing. Using a commonly used polyurethane coating from a certain oilfield as a control group, tests were conducted in a NaOH solution at a test temperature of 150℃, a pressure of 35 MPa, and a pH of 13. The pure polyurethane coating exhibited bubbling, while the composite coating of fluorinated acrylate / graphene-modified polyurethane showed no significant change before and after the test, indicating that the composite coating of fluorinated acrylate / graphene-modified polyurethane has good anti-corrosion properties.

[0039] Example 2

[0040] A method for preparing a fluorinated acrylate / graphene modified polyurethane coating includes the following steps:

[0041] S1: Add 30g of styrene (ST) and 18g of tridecyl fluorooctyl methacrylate (PFOMA) to a three-necked flask, wash thoroughly with 100mL of deionized water until the pH of the washing solution is neutral; then add 24g of azobisisobutyronitrile (AIBN), mix and stir evenly, then heat to 80℃ and keep warm for 12h to obtain the reaction product. The reaction product is repeatedly washed and precipitated with methanol, and finally dried in a constant temperature drying oven at 75℃ for 6h to obtain a fluorinated acrylate copolymer.

[0042] 20g of fluorinated acrylate copolymer and 3g of graphene (RGO) were dissolved in 100mL of dichloromethane, stirred evenly and ultrasonically dispersed for 30min to obtain fluorinated acrylate / graphene dispersion.

[0043] S2: Place 100g of polypropylene glycol (PPG-1000) and 100g of dimethylolpropionic acid (DMPA) into a beaker, place it in a vacuum drying oven at 70℃, and vacuum dry for 2 hours to perform vacuum dehydration treatment, so that the dimethylolpropionic acid is completely dissolved to obtain a mixed solution; after drying, remove the beaker, and after the beaker cools to room temperature, add 90g of toluene diisocyanate (TDI) to the mixed solution and keep it at 75℃ for 4 hours to obtain a polyurethane prepolymer; cool the polyurethane prepolymer to room temperature and add an appropriate amount of acetone to adjust the viscosity to 95ku;

[0044] S3: Mix 560g of polyurethane prepolymer and 20g of triethylamine (TEA) and neutralize for 2h to obtain mixed solution A; add 12g of ethylenediamine (EDA) and 20g of triaminopropylsiloxane (APTES) to mixed solution A and continue the reaction for 1h to obtain mixed solution B; add 157g of fluorinated acrylate / graphene dispersion to mixed solution B and stir at 2000r / min, and shear emulsify for 0.5h to obtain fluorinated acrylate / graphene modified polyurethane coating.

[0045] The viscosity of the fluorinated acrylate / graphene-modified polyurethane coating prepared in Example 2 was adjusted to 90 kDa, and 180 g of pigments and fillers were added and mixed evenly. The mixture was then sprayed onto the surface of the water injection well tubing. After curing at room temperature, a composite coating of fluorinated acrylate / graphene-modified polyurethane was obtained on the surface of the water injection well tubing. The water contact angle of the fluorinated acrylate / graphene-modified polyurethane composite coating in Example 2 was tested, with a polyurethane coating used in an oilfield as a control group. The coating was immersed in a 10% NaCl solution at 50°C for 10 days. The test results showed that the water contact angle of the graphene-modified polyurethane composite coating was 94°, exhibiting good hydrophobic properties, while the water contact angle of the polyurethane coating used in the oilfield was 73°, exhibiting hydrophilic properties.

[0046] Example 3

[0047] A method for preparing a fluorinated acrylate / graphene modified polyurethane coating includes the following steps:

[0048] S1: Add 50g of styrene (ST) and 30g of tridecyl fluorooctyl methacrylate (PFOMA) to a three-necked flask, and wash thoroughly with 100mL of deionized water until the pH of the washing solution is neutral; then add 18g of azobisisobutyronitrile (AIBN), mix and stir evenly, and then heat to 70℃ and keep warm for 15h to obtain the reaction product. The reaction product is repeatedly washed and precipitated with methanol, and finally dried in a constant temperature drying oven to obtain a fluorinated acrylate copolymer.

[0049] 20g of fluorinated acrylate copolymer and 5g of graphene (RGO) were dissolved in 80mL of dichloromethane, stirred evenly and ultrasonically dispersed for 20min to obtain fluorinated acrylate / graphene dispersion.

[0050] S2: 360g of polypropylene glycol (PPG-1000) and 360g of dimethylolpropionic acid (DMPA) were placed in a beaker and placed in a vacuum drying oven at 65℃ for 3 hours to perform vacuum dehydration treatment, so that the dimethylolpropionic acid was completely dissolved to obtain a mixed solution. After drying, the beaker was removed and allowed to cool to room temperature. Then, 160g of toluene diisocyanate (TDI) was added to the mixed solution and the mixture was kept at 80℃ for 6 hours to obtain a polyurethane prepolymer. The polyurethane prepolymer was cooled to room temperature and an appropriate amount of acetone was added to adjust the viscosity.

[0051] S3: Mix 880g of polyurethane prepolymer and 25g of triethylamine (TEA) and neutralize for 3h to obtain mixed solution A; add 15g of ethylenediamine (EDA) and 30g of triaminopropylsiloxane (APTES) to mixed solution A and continue the reaction for 1h to obtain mixed solution B; add 132g of fluorinated acrylate / graphene dispersion to mixed solution B and stir at 2000r / min, and shear emulsify for 1.5h to obtain fluorinated acrylate / graphene modified polyurethane coating.

[0052] The viscosity of the fluorinated acrylate / graphene-modified polyurethane coating prepared in Example 3 was adjusted to 90 kDa. 250 g of pigments and fillers were added and mixed thoroughly. The mixture was then sprayed onto the surface of a pre-treated tubing steel sheet. After room temperature curing, a composite coating of fluorinated acrylate / graphene-modified polyurethane was obtained on the surface of the water injection well tubing. Adhesion tests were performed on the fluorinated acrylate / graphene-modified polyurethane composite coating from Example 3, using a polyurethane coating already in use in an oilfield as a control group. Following the requirements of standard SY T6717-2016, a tool was used to make cross-cuts on the coating down to the substrate, with a cut length of approximately 40 mm and a cut angle of 30°–45°. The test results showed that the fluorinated acrylate / graphene-modified polyurethane composite coating still exhibited good adhesion performance after being cut with a tool and torn with tape. In contrast, the polyurethane coating already in use in the oilfield showed obvious bulging at the cut points, indicating a significant decrease in adhesion.

[0053] Example 4

[0054] A method for preparing a fluorinated acrylate / graphene modified polyurethane coating includes the following steps:

[0055] S1: Add 40g of styrene (ST) and 24g of tridecyl fluorooctyl methacrylate (PFOMA) to a three-necked flask, wash thoroughly with 100mL of deionized water until the pH of the washing solution is neutral; then add 16g of azobisisobutyronitrile (AIBN), mix and stir evenly, then heat to 80℃ and keep warm for 12h to obtain the reaction product. The reaction product is repeatedly washed and precipitated with methanol, and finally dried in a constant temperature drying oven at 70℃ for 2h to obtain a fluorinated acrylate copolymer.

[0056] 20g of fluorinated acrylate copolymer and 4g of graphene (RGO) were dissolved in 70mL of dichloromethane, stirred evenly and ultrasonically dispersed for 30min to obtain fluorinated acrylate / graphene dispersion.

[0057] S2: Place 100g of polypropylene glycol (PPG-1000) and 100g of dimethylolpropionic acid (DMPA) into a beaker, place it in a vacuum drying oven at 70℃, and vacuum dry for 2 hours to perform vacuum dehydration treatment, so that the dimethylolpropionic acid is completely dissolved to obtain a mixed solution; after drying, remove the beaker, and after the beaker cools to room temperature, add 90g of toluene diisocyanate (TDI) to the mixed solution and keep it at 75℃ for 4 hours to obtain a polyurethane prepolymer; cool the polyurethane prepolymer to room temperature and add an appropriate amount of acetone to adjust the viscosity;

[0058] S3: 290g of polyurethane prepolymer was thoroughly stirred and then added to 12g of triethylamine (TEA) for neutralization and reaction for 2h; mixed solution A was obtained; 12g of ethylenediamine (EDA) and 20g of triaminopropylsiloxane (APTES) were added to mixed solution A and the reaction was continued for 0.5h to obtain mixed solution B; 118g of fluorinated acrylate / graphene dispersion was added to mixed solution B and stirred at 1800r / min, and shear emulsified for 0.5h to obtain fluorinated acrylate / graphene modified polyurethane coating.

[0059] The viscosity of the fluorinated acrylate / graphene-modified polyurethane coating prepared in Example 4 was adjusted to 90 kDa, and 180 g of pigments and fillers were added and mixed evenly. The mixture was then sprayed onto the surface of the water injection well tubing. After room temperature curing, a composite coating of fluorinated acrylate / graphene-modified polyurethane was obtained on the surface of the water injection well tubing. A sand-fall test was conducted on the fluorinated acrylate / graphene-modified polyurethane composite coating from Example 4, using a polyurethane coating already in use in an oilfield as a control group. The test results showed that the graphene-modified polyurethane composite coating had an abrasion resistance value of 8.6, exhibiting good abrasion resistance, while the polyurethane coating already in use in the oilfield had a water contact angle of 6.9°, indicating lower abrasion resistance.

[0060] Example 5

[0061] A method for preparing a fluorinated acrylate / graphene modified polyurethane coating includes the following steps:

[0062] S1: Add 45g of styrene (ST) and 27g of tridecyl fluorooctyl methacrylate (PFOMA) to a three-necked flask, and wash thoroughly with 100mL of deionized water until the pH of the washing solution is neutral; then add 18g of azobisisobutyronitrile (AIBN), mix and stir evenly, and then heat to 70℃ and keep warm for 12h to obtain the reaction product. The reaction product is repeatedly washed and precipitated with methanol, and finally dried in a constant temperature drying oven to obtain a fluorinated acrylate copolymer.

[0063] 20g of fluorinated acrylate copolymer and 2.5g of graphene (RGO) were dissolved in 90mL of dichloromethane, stirred evenly and ultrasonically dispersed for 20min to obtain fluorinated acrylate / graphene dispersion.

[0064] S2: 360g of polypropylene glycol (PPG-1000) and 360g of dimethylolpropionic acid (DMPA) were placed in a beaker and placed in a vacuum drying oven at 70℃ for 2 hours to perform vacuum dehydration treatment, so that the dimethylolpropionic acid was completely dissolved to obtain a mixed solution. After drying, the beaker was removed and allowed to cool to room temperature. Then, 160g of toluene diisocyanate (TDI) was added to the mixed solution and the mixture was kept at 75℃ for 4 hours to obtain a polyurethane prepolymer. The polyurethane prepolymer was cooled to room temperature and an appropriate amount of acetone was added to adjust the viscosity.

[0065] S3: 880g of polyurethane prepolymer was thoroughly stirred and then added to 16g of triethylamine (TEA) for neutralization and reaction for 2h; mixed solution A was obtained; 22g of ethylenediamine (EDA) and 30g of triaminopropylsiloxane (APTES) were added to mixed solution A and the reaction was continued for 1h to obtain mixed solution B; 144g of fluorinated acrylate / graphene dispersion was added to mixed solution B and stirred at 2200r / min, and shear emulsified for 0.5h to obtain fluorinated acrylate / graphene modified polyurethane coating.

[0066] The viscosity of the fluorinated acrylate / graphene modified polyurethane coating prepared in Example 5 was adjusted to 90 kDa, and 180 g of pigments and fillers were added and mixed evenly. The mixture was then sprayed onto the surface of the water injection well tubing. After curing at room temperature, a composite coating of fluorinated acrylate / graphene modified polyurethane was obtained on the surface of the water injection well tubing.

[0067] The fluorinated acrylate / graphene-modified polyurethane composite coating in Example 5 was subjected to high-temperature and high-pressure tests, with a polyurethane coating used in an oil field as a control group. At an experimental temperature of 148°C, a pressure of 12 MPa, and a test time of 24 hours, the pure polyurethane coating showed bubbling, while the fluorinated acrylate / graphene-modified polyurethane composite coating showed no significant changes before and after the test. This indicates that the fluorinated acrylate / graphene-modified polyurethane composite coating has good high-temperature and high-pressure resistance.

[0068] Example 6

[0069] A method for preparing a fluorinated acrylate / graphene modified polyurethane coating includes the following steps:

[0070] S1: Add 25g of styrene (ST) and 15g of tridecyl fluorooctyl methacrylate (PFOMA) to a three-necked flask, and wash thoroughly with 100mL of deionized water until the pH of the washing solution is neutral; then add 12g of azobisisobutyronitrile (AIBN), mix and stir evenly, and then heat to 70℃ and keep warm for 12h to obtain the reaction product. The reaction product is repeatedly washed and precipitated with methanol, and finally dried in a constant temperature drying oven to obtain a fluorinated acrylate copolymer.

[0071] 22g of fluorinated acrylate copolymer and 2.5g of graphene (RGO) were dissolved in 100mL of dichloromethane, stirred evenly and ultrasonically dispersed for 15min to obtain a fluorinated acrylate / graphene dispersion.

[0072] S2: 360g of polypropylene glycol (PPG-1000) and 300g of dimethylolpropionic acid (DMPA) were placed in a beaker and placed in a vacuum drying oven at 65℃ for 2 hours to perform vacuum dehydration treatment, so that the dimethylolpropionic acid was completely dissolved to obtain a mixed solution. After drying, the beaker was removed and allowed to cool to room temperature. Then, 80g of toluene diisocyanate (TDI) was added to the mixed solution and the mixture was kept at 75℃ for 6 hours to obtain a polyurethane prepolymer. The polyurethane prepolymer was cooled to room temperature and an appropriate amount of acetone was added to adjust the viscosity.

[0073] S3: 900g of polyurethane prepolymer was thoroughly stirred and then added to 30g of triethylamine (TEA) for neutralization and reaction for 3h; mixed solution A was obtained; 22g of ethylenediamine (EDA) and 30g of triaminopropylsiloxane (APTES) were added to mixed solution A and the reaction was continued for 1h to obtain mixed solution B; 160g of fluorinated acrylate / graphene dispersion was added to mixed solution B and stirred at 2200r / min, and shear emulsified for 0.5h to obtain fluorinated acrylate / graphene modified polyurethane coating.

[0074] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for preparing a fluorinated acrylate / graphene modified polyurethane coating, characterized in that, Includes the following steps: S1: Fluorinated acrylate copolymer, graphene and dichloromethane are mixed to obtain fluorinated acrylate / graphene dispersion; S2: Polypropylene glycol and dimethylolpropionic acid are mixed and then subjected to vacuum dehydration to completely dissolve the dimethylolpropionic acid, resulting in a mixed solution; toluene diisocyanate is then added to the mixed solution, and after reaction, a polyurethane prepolymer is obtained. S3: The polyurethane prepolymer and triethylamine are mixed and reacted to obtain mixed solution A; ethylenediamine and triaminopropylsiloxane are added to mixed solution A and reacted to obtain mixed solution B; fluorinated acrylate / graphene dispersion is added to mixed solution B and stirred and sheared to obtain fluorinated acrylate / graphene modified polyurethane coating. In S1, the preparation method of the fluorinated acrylate copolymer is as follows: styrene and tridecafluorooctyl methacrylate are mixed and washed until the washing solution is neutral. Then, an initiator is added, and after heating and heat preservation, a reaction product is obtained. The reaction product is then rinsed, precipitated, and dried to obtain the fluorinated acrylate copolymer. The ratio of styrene, tridecafluorooctyl methacrylate, and initiator is (25~50) g: (15~30) g: (12~24) g. The temperature is raised to 70~80℃ and the heat preservation time is 12~15 h. The initiator is azobisisobutyronitrile. In S3, the ratio of the amount of triethylamine, ethylenediamine and triaminopropylsiloxane is (12~30) g: (8~22) g: (15~30) g; the ratio of the amount of triaminopropylsiloxane and fluorinated acrylate / graphene dispersion is (15~30) g: (85~160) g.

2. The method for preparing a fluorinated acrylate / graphene modified polyurethane coating according to claim 1, characterized in that, In S1, the ratio of the fluorinated acrylate copolymer, graphene, and dichloromethane is (18-22) g: (1.5-5) g: (50-100) mL; after mixing the fluorinated acrylate copolymer, graphene, and dichloromethane, the mixture is ultrasonically dispersed for 15-20 minutes to obtain a fluorinated acrylate / graphene dispersion.

3. The method for preparing a fluorinated acrylate / graphene modified polyurethane coating according to claim 1, characterized in that, In S2, the ratio of polypropylene glycol, dimethylolpropionic acid, and toluene diisocyanate is (100~360) g: (100~360) g: (80~160) g; the vacuum dehydration treatment is carried out in a vacuum drying oven at 65℃~80℃ for 2h~3h; after the temperature of the mixed solution drops to room temperature, toluene diisocyanate is added, and after reacting at 75℃~80℃ for 3h~6h, a polyurethane prepolymer is obtained.

4. The method for preparing a fluorinated acrylate / graphene modified polyurethane coating according to claim 1, characterized in that, In S3, the ratio of polyurethane prepolymer to triethylamine is (270~900) g: (12~30) g.

5. The method for preparing a fluorinated acrylate / graphene modified polyurethane coating according to claim 1, characterized in that, In S3, the reaction time is 0.5 h to 3 h; the stirring is carried out at a stirring speed of 1800 r / min to 2200 r / min; and the shear emulsification time is 0.5 h to 1.5 h.

6. A fluorinated acrylate / graphene modified polyurethane coating, characterized in that, The coating is prepared using the method described in any one of claims 1 to 5 for a fluorinated acrylate / graphene modified polyurethane coating.

7. The application of the fluorinated acrylate / graphene modified polyurethane coating according to claim 6, characterized in that, The fluorinated acrylate / graphene modified polyurethane coating is used as a surface protective coating for water injection well tubing. When the fluorinated acrylate / graphene modified polyurethane coating is used as a surface protective coating for water injection well tubing, the steps are as follows: First, adjust the viscosity of the fluorinated acrylate / graphene modified polyurethane coating to 85~95 kDa, then add pigments and fillers and mix evenly. Then, spray it onto the surface of the water injection well tubing. After curing at room temperature, a composite coating of fluorinated acrylate / graphene modified polyurethane is obtained on the surface of the water injection well tubing.

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