A fouling and scale-inhibiting coating for oil-water gathering and transportation pipelines and its preparation method

Abstract

This invention relates to the field of antifouling and scale inhibition in oil-water gathering and transportation pipelines, and discloses an antifouling and scale inhibition coating for oil-water gathering and transportation pipelines and its preparation method. The preparation method includes the following steps: esterification reaction of a biomass-based antifouling agent with a haloacyl halide; grafting the esterified antifouling agent onto the polymer backbone via a quaternization reaction; dissolving the grafted modified polymer in a coating thinner; adding a dispersant, defoamer, and leveling agent to the diluted polymer; and coating the resulting mixture onto the surface of a substrate and curing at room temperature to obtain the antifouling and scale inhibition coating. This invention uses biomass-based antifouling agents such as capsaicin, carvacrol, and salicylic acid, reducing environmental toxicity and providing good environmental benefits; the preparation process is simple and easy to implement, the reaction conditions are mild, and it is suitable for large-area construction; the prepared antifouling and scale inhibition coating is a biomass-based leaching / non-leaching tiered antifouling coating, exhibiting a tiered antifouling effect.

Description

Technical Field

[0001] This invention relates to the field of antifouling and scale prevention in oil and water gathering and transportation pipelines, specifically to an antifouling and scale-inhibiting coating for oil and water gathering and transportation pipelines and its preparation method. Background Technology

[0002] Biofouling and scaling refer to the phenomenon of various contaminants, bacteria, algae, etc., adhering to and growing on the surface of oil-water gathering and transportation pipelines. Biofouling on the inner wall of oilfield gathering and transportation pipelines not only reduces transportation efficiency, accelerates corrosion of the metal substrate, and increases pipeline maintenance costs, but also leads to scaling on the inner wall of the pipeline due to the participation of organisms in the mineralization process. Currently, antifouling coatings are one of the simplest and most economical means to deal with biofouling and scaling. Commonly used antifouling mechanisms of coatings are divided into leaching antifouling and non-leaching antifouling. The former refers to the release of biocide from the coating into the environment under mechanical wear or hydrolysis, which has a bactericidal and antifouling effect. The latter refers to the cross-linking of biocide as functional groups into the resin. When biofouling comes into contact with the coating surface, the cross-linked antifouling groups trigger the death of bacteria, thus exerting an antifouling effect. In addition, the selection of raw materials for preparing antifouling coatings needs to consider environmental friendliness and long-term effectiveness. In order to extend the antifouling life of the coating, leaching / non-leaching tiered antifouling coatings can be prepared, and biomass-based antifouling agents can be introduced into the coating. For example, CN112159609A discloses a leaching-type nano-silver antibacterial coating, but this coating uses precious metal nanoparticles, increasing the preparation cost, and relies solely on leached Ag. + Its anti-fouling lifespan is limited.

[0003] Biomass-based antifouling agents, as the name suggests, utilize antifouling agents or derivatives derived from biomass and incorporate them into antifouling coatings, such as capsaicin, carvacrol, and salicylic acid. These biomass antifouling agents have minimal environmental toxicity during service and offer significant antifouling effects. For example, capsaicin possesses excellent antioxidant properties and exhibits significant inhibitory effects on both Gram-negative and Gram-positive bacteria, and has been incorporated into organic coatings as an antifouling agent.

[0004] Currently, antifouling coatings can be divided into two categories: leaching-type and non-leaching-type coatings, such as those that release heavy metal antibacterial ions Au. + Ag + Cu 2+ Alternatively, anchoring the antifouling agent within the cross-linked network of the coating resin can inhibit the growth of biofouling on the coating surface. For example, CN105431482B developed a hyperbranched polyalkoxysiloxane additive for antifouling surface coatings, and CN102933666B authorized an adhesive for self-polishing antifouling coatings. However, these antifouling coatings are limited to leached or non-leached contact antifouling agents; there are no reports on biomass-based leached / non-leached tiered antifouling coatings. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, this invention provides an antifouling and scale-inhibiting coating for oil-water gathering and transportation pipelines and its preparation method. The core of this invention lies in developing a biomass-based leaching / non-leaching tiered antifouling and scale-inhibiting coating for oil-water gathering and transportation pipelines. The technical solution is as follows:

[0006] A method for preparing an antifouling and scale-inhibiting coating for oil-water gathering and transportation pipelines, comprising the following steps:

[0007] (1) The biomass-based antifouling agent undergoes an esterification reaction with a haloacyl halide;

[0008] (2) The antifouling agent after esterification in step (1) is grafted onto the polymer backbone through a quaternization reaction;

[0009] (3) Dissolve the grafted and modified polymer from step (2) into the coating thinner;

[0010] (4) Add dispersant, defoamer and leveling agent to the diluted polymer obtained in step (3);

[0011] (5) Apply the mixture obtained in step (4) to the surface of the substrate and cure at room temperature to obtain an antifouling and scale-inhibiting coating.

[0012] The biomass-based antifouling agent in step (1) is one or more of salicylic acid, carvacrol, capsaicin and betaine.

[0013] In step (1), the halogenated acyl halide is bromoacetyl bromide.

[0014] The polymer in step (2) is one or more of polyurethane, polydimethylsiloxane, epoxy resin and alkyd resin.

[0015] In step (2), the mass ratio of the polymer to the esterified antifouling agent is (1:3) to (1:10).

[0016] The mass ratio between the grafted and modified polymer and the coating thinner in step (3) is (1:2) to (1:10).

[0017] The paint thinner in step (3) is one or more of xylene, acetone and methyl ethyl ketone.

[0018] The dispersant in step (4) is one or two of N,N-dimethylformamide, BYK140 and BYK142.

[0019] The defoamer in step (4) is A-065, A-141 or A-530.

[0020] The leveling agent used in step (4) is F370, MONENG-1080, or Solvesso 150.

[0021] The substrates used in step (5) include metal, glass, and plastic.

[0022] The coating thickness in step (5) is between 20μm and 200μm, and can be freely adjusted according to the application scenario and the service life of the coating.

[0023] The coating process in step (5) includes brushing, dipping, spraying, and spraying.

[0024] The biomass antifouling agent has a mass content of 5% to 50% in the final coating. When the content is less than 5%, the antifouling effect is not obvious; when the content is greater than 50%, the film-forming properties of the coating are poor.

[0025] The basic process flow of the esterification reaction of the biomass-based antifouling agent using salicylic acid is as follows: salicylic acid, 4-dimethylaminopyridine, and pyridine are added to anhydrous diethyl ether and cooled in an ice bath. Then, bromoacetyl bromide is slowly added dropwise to react. After the liquid phase is dried, it is dissolved in ethanol to precipitate and recrystallized in water. The obtained product is added with MgSO4, concentrated sulfuric acid, and tert-butanol. The reaction product is dried for later use.

[0026] The basic process flow of the esterification reaction of the biomass-based antifouling agent using carvacrol is as follows: carvacrol, 4-dimethylaminopyridine, and pyridine are added to anhydrous diethyl ether and cooled in an ice bath, followed by slow dropwise addition of bromoacetyl bromide. After liquid phase drying, the product is separated by column chromatography and eluted with a mixture of ethyl acetate, butyl acetate, n-hexane, and n-octane. The obtained product is then vacuum dried.

[0027] The basic process flow of the esterification reaction when the biomass-based antifouling agent uses capsaicin is as follows: capsaicin, 4-dimethylaminopyridine, and pyridine are added to anhydrous diethyl ether and cooled in an ice bath, followed by slow dropwise addition of bromoacetyl bromide for reaction. After liquid phase drying, the product is dissolved in a mixed solvent of ethanol, n-propanol, and n-octanol, recrystallized in water, and the resulting product is then vacuum dried.

[0028] The synthesis route of the polyurethane is as follows: N-methyldiethanolamine and isophorone diisocyanate are subjected to a polycondensation reaction, with dibutyltin laurate as a catalyst, nitrogen protection, N,N-dimethylformamide as a solvent, and then 3-aminopropyltriethoxysilane is added for end capping.

[0029] A fouling and scale-inhibiting coating for oil-water gathering and transportation pipelines is prepared by the above-described method for preparing a fouling and scale-inhibiting coating for oil-water gathering and transportation pipelines.

[0030] Compared with the prior art, the present invention has the following main advantages:

[0031] 1. By selecting biomass-based antifouling agents such as capsaicin, carvacrol, and salicylic acid, the toxic effects on the environment are reduced, resulting in good environmental benefits.

[0032] 2. The preparation process of this invention is simple and easy to implement, with mild reaction conditions, making it suitable for large-scale construction. It mainly involves a two-step grafting modification process: esterification and quaternization. The esterification reaction involves reacting the phenolic hydroxyl groups of the biomass-based antifouling agent with bromoacetyl bromide, while the quaternization reaction involves grafting the esterified antifouling agent onto the polymer backbone.

[0033] 3. The antifouling and scale-inhibiting coating prepared by this invention belongs to the biomass-based leaching / non-leaching type tiered antifouling coating, exhibiting a tiered antifouling effect. When the coating is immersed in oilfield wastewater, the phenolic ester bonds of the coating surface hydrolyze upon contact with the aqueous solution, first releasing the biomass-based antifouling agent to achieve leaching-type antifouling. After hydrolysis, the coating surface exposes betaine-type quaternary ammonium salt groups, at which point the coating achieves contact sterilization and scale prevention through non-leaching low surface energy molecules.

[0034] 4. The antifouling and scale-inhibiting coating prepared by the present invention kills microorganisms under the scale by releasing biomass bactericides through leaching, and peels off together with the scale layer; in the later stage of the coating's service life, it achieves green and long-lasting antifouling and scale prevention through contact killing of microorganisms by the fixed quaternary ammonium salt groups.

[0035] 5. The antifouling and scale-inhibiting coating prepared by this invention has excellent gloss and excellent adhesion.

[0036] 6. The antifouling and scale-inhibiting coating prepared by this invention is suitable for application on various object surfaces. This coating can be used for the protective coating of oil-water gathering and transportation pipelines, and also for the surface of large ship materials to inhibit the adhesion of biofouling. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the anti-fouling and anti-scaling coating of the present invention;

[0038] Figure 2 The chemical reaction formula for a two-step salicylic acid modified coating;

[0039] Figure 3 The release curves of salicylic acid in Examples 1 and 3 are shown.

[0040] Figure 4 These are fluorescent micrographs of the antibacterial adhesion of the coatings in Examples 1 and 3;

[0041] Figure 5 This is a schematic diagram illustrating the antibacterial adhesion of the coating as shown in Examples 1 and 3. Detailed Implementation

[0042] The present invention will now be described in detail with reference to the embodiments and accompanying drawings. It should be noted that the following embodiments are merely representative examples of the overall technical solution, that is, the present invention is not limited to the following embodiments. Example 1

[0043] like Figure 2 10g of salicylic acid, 54mg of 4-dimethylaminopyridine (DMAP), and 5.86mL of pyridine were added to 100mL of anhydrous diethyl ether and cooled to 0℃ in an ice bath. Then, 7.56mL of bromoacetyl bromide was slowly added dropwise and reacted for 16h. The liquid phase was dried on a rotary vacuum evaporator, then dissolved in ethanol to precipitate, recrystallized in water, and the resulting product was dried under vacuum.

[0044] 4.81 g of anhydrous MgSO4 and 0.55 mL of concentrated sulfuric acid were added to 40 mL of dichloromethane and stirred at room temperature for 15 minutes. The product from the previous step (2.6 g, 10 mmol) and tert-butanol (4.78 mL, 50 mmol) were added sequentially to the stirred dichloromethane solution. The mixture was stirred at 25 °C for 18 h. The reaction was terminated by adding 75 mL of saturated sodium bicarbonate solution, which dissolved the MgSO4. The dichloromethane organic phase was then washed three times with brine, followed by drying with anhydrous Na2SO4 for 12 h. Finally, the dichloromethane was removed using a rotary vacuum evaporator, and the product was dried for later use.

[0045] 860 mL of N-methyldiethanolamine and 2.17 g of isophorone diisocyanate were subjected to a polycondensation reaction (molar ratio 1:1.3), with 0.05 g of dibutyltin laurylate (DBTDL) added as a catalyst and nitrogen protection applied. The reaction solution was 30 mL of N,N-dimethylformamide, and then 2 mL of 3-aminopropyltriethoxysilane (KH550) was added for end capping. The product from the previous step was then added to quaternize the polyurethane backbone by grafting antifouling groups (mass ratio 1:3) to obtain sample A.

[0046] Then, add BYK140 dispersant, F370 leveling agent and A-065 defoamer to sample A and stir until a mixture is formed. The amount of dispersant added is 0.5% of the mass of sample A, the amount of leveling agent added is 0.002% of the mass of sample A, and the amount of defoamer added is 0.002% of the mass of sample A. Then place it in a vacuum oven to remove air bubbles.

[0047] Finally, the mixture is brushed onto a carbon steel substrate and cured at room temperature for 7 days to obtain an anti-fouling coating with a thickness of 100mm.

[0048] The coating formed by the present invention has a hydrolyzable leaching bactericide and an adhesive antifouling group exposed after hydrolysis. Example 2

[0049] 10g of salicylic acid, 54mg of 4-dimethylaminopyridine (DMAP), and 5.86mL of pyridine were added to 100mL of anhydrous diethyl ether and cooled to 0℃ in an ice bath. Then, 7.56mL of bromoacetyl bromide was slowly added dropwise and reacted for 16h. The liquid phase was dried on a rotary vacuum evaporator, then dissolved in ethanol, recrystallized in water, and the resulting product was dried under vacuum.

[0050] 4.81 g of anhydrous MgSO4 and 0.55 mL of concentrated sulfuric acid were added to 40 mL of dichloromethane and stirred at room temperature for 15 minutes. The product from the previous step (2.6 g, 10 mmol) and tert-butanol (4.78 mL, 50 mmol) were added sequentially to the stirred dichloromethane solution. The mixture was stirred at 25 °C for 18 h. The reaction was terminated by adding 75 mL of saturated sodium bicarbonate solution, which also dissolved the MgSO4. The dichloromethane organic phase was then washed three times with brine and dried over anhydrous Na2SO4 for 12 h. Finally, the dichloromethane was removed using a rotary vacuum evaporator, and the product was dried for later use.

[0051] 860 mL of N-methyldiethanolamine and 2.17 g of isophorone diisocyanate were subjected to a polycondensation reaction (molar ratio 1:1.3), with 0.05 g of dibutyltin laurylate (DBTDL) added as a catalyst and nitrogen protection applied. The reaction solution was 30 mL of N,N-dimethylformamide, and then 2 mL of 3-aminopropyltriethoxysilane (KH550) was added for end capping. The product from the previous step was then added to quaternize the polyurethane backbone by grafting antifouling groups (mass ratio 1:5) to obtain sample B.

[0052] Then, BYK140 dispersant, F370 leveling agent, and A-065 defoamer were added to sample B and stirred evenly to form a mixture. The amount of dispersant added was 0.5% of the mass of sample B, the amount of leveling agent added was 0.002% of the mass of sample B, and the amount of defoamer added was 0.002% of the mass of sample B. Then, the sample was placed in a vacuum oven and vacuumed to remove air bubbles.

[0053] The mixture is brushed onto a carbon steel substrate and cured at room temperature for 7 days to obtain an anti-fouling coating with a thickness of 100 mm. Example 3

[0054] 10g of salicylic acid, 54mg of 4-dimethylaminopyridine (DMAP), and 5.86mL of pyridine were added to 100mL of anhydrous diethyl ether and cooled to 0℃ in an ice bath. Then, 7.56mL of bromoacetyl bromide was slowly added dropwise and reacted for 16h. The liquid phase was dried on a rotary vacuum evaporator, then dissolved in ethanol, recrystallized in water, and the resulting product was dried under vacuum.

[0055] 4.81 g of anhydrous MgSO4 and 0.55 mL of concentrated sulfuric acid were added to 40 mL of dichloromethane. The mixture was stirred at room temperature for 15 minutes. The product from the previous step (2.6 g, 10 mmol) and tert-butanol (4.78 mL, 50 mmol) were added sequentially to the stirred dichloromethane solution. The mixture was stirred at 25 °C for 18 h. The reaction was terminated by adding 75 mL of saturated sodium bicarbonate solution, which dissolved the MgSO4. The dichloromethane organic phase was then washed three times with brine and dried over anhydrous Na2SO4 for 12 h. Finally, the dichloromethane was removed using a rotary vacuum evaporator, and the product was dried for later use.

[0056] 860 mL of N-methyldiethanolamine and 2.17 g of isophorone diisocyanate were subjected to a polycondensation reaction (molar ratio 1:1.3), with 0.05 g of dibutyltin laurylate (DBTDL) added as a catalyst and nitrogen protection applied. The reaction solution was 30 mL of N,N-dimethylformamide, and then 2 mL of 3-aminopropyltriethoxysilane (KH550) was added for end capping. The product from the previous step was then added to quaternize the polyurethane backbone by grafting antifouling groups (mass ratio 1:10) to obtain sample C.

[0057] Then, add BYK140 dispersant, F370 leveling agent and A-065 defoamer to sample C and stir until a mixture is formed. The amount of dispersant added is 0.5% of the mass of sample C, the amount of leveling agent added is 0.002% of the mass of sample C, and the amount of defoamer added is 0.002% of the mass of sample C. Then, place it in a vacuum oven to remove air bubbles.

[0058] The mixture is brushed onto a carbon steel substrate and cured at room temperature for 7 days to obtain an anti-fouling coating with a thickness of 100 mm. Example 4

[0059] 10g of salicylic acid, 54mg of 4-dimethylaminopyridine (DMAP), and 5.86mL of pyridine were added to 100mL of anhydrous diethyl ether and cooled to 0℃ in an ice bath. Then, 7.56mL of bromoacetyl bromide was slowly added dropwise and reacted for 16h. The liquid phase was dried on a rotary vacuum evaporator, then dissolved in ethanol, recrystallized in water, and the resulting product was dried under vacuum.

[0060] 4.81 g of anhydrous MgSO4 and 0.55 mL of concentrated sulfuric acid were added to 40 mL of dichloromethane. The mixture was stirred at room temperature for 15 minutes. The product from the previous step (2.6 g, 10 mmol) and tert-butanol (4.78 mL, 50 mmol) were added sequentially to the stirred dichloromethane solution. The mixture was stirred at 25 °C for 18 h. The reaction was terminated by adding 75 mL of saturated sodium bicarbonate solution, which dissolved the MgSO4. The dichloromethane organic phase was then washed three times with brine and dried over anhydrous Na2SO4 for 12 h. Finally, the dichloromethane was removed using a rotary vacuum evaporator, and the product was dried for later use.

[0061] 860 mL of N-methyldiethanolamine and 2.17 g of isophorone diisocyanate were subjected to a polycondensation reaction (molar ratio 1:1.3), with 0.05 g of dibutyltin laurylate (DBTDL) added as a catalyst and nitrogen protection applied. The reaction solution was a mixture of 30 mL of N,N-dimethylformamide and xylene in equal volumes. Then, 2 mL of 3-aminopropyltriethoxysilane (KH550) was added for end capping. The product from the previous step was then added to quaternize the polyurethane backbone by grafting antifouling groups (mass ratio 1:10) to obtain sample C.

[0062] 1g of polydimethylsiloxane was diluted in a 2g mixture of xylene, acetone, and methyl ethyl ketone (mass ratio 1:2). 0.02g of methyltriacetoxysilane (METES) and 0.1g of dibutyltin laurylate (DBTDL) were added, and the mixture was stirred at 25°C for 30 min. Then, 1g of sample C, BYK140 dispersant, F370 leveling agent, and A-065 defoamer were added to the mixture and stirred until homogeneous to form a homogeneous mixture. The amount of dispersant added was 0.5% of the mass of sample C, the amount of leveling agent added was 0.002% of the mass of sample C, and the amount of defoamer added was 0.002% of the mass of sample C. The mixture was then placed in a vacuum oven and vacuumed to remove air bubbles.

[0063] The mixture is brushed onto a carbon steel substrate and cured at room temperature for 7 days to obtain an anti-fouling coating with a thickness of 20 mm. Example 5

[0064] 10g of salicylic acid, 54mg of 4-dimethylaminopyridine (DMAP), and 5.86mL of pyridine were added to 100mL of anhydrous diethyl ether and cooled to 0℃ in an ice bath. Then, 7.56mL of bromoacetyl bromide was slowly added dropwise and reacted for 16h. The liquid phase was dried on a rotary vacuum evaporator, then dissolved in ethanol, recrystallized in water, and the resulting product was dried under vacuum.

[0065] 4.81 g of anhydrous MgSO4 and 0.55 mL of concentrated sulfuric acid were added to 40 mL of dichloromethane. The mixture was stirred at room temperature for 15 minutes. The product from the previous step (2.6 g, 10 mmol) and tert-butanol (4.78 mL, 50 mmol) were added sequentially to the stirred dichloromethane solution. The mixture was stirred at 25 °C for 18 h. The reaction was terminated by adding 75 mL of saturated sodium bicarbonate solution, which dissolved the MgSO4. The dichloromethane organic phase was then washed three times with brine and dried over anhydrous Na2SO4 for 12 h. Finally, the dichloromethane was removed using a rotary vacuum evaporator, and the product was dried for later use.

[0066] 860 mL of N-methyldiethanolamine and 2.17 g of isophorone diisocyanate were subjected to a polycondensation reaction (molar ratio 1:1.3), with 0.05 g of dibutyltin laurylate (DBTDL) added as a catalyst and nitrogen protection applied. The reaction solution was a mixture of 30 mL of N,N-dimethylformamide and xylene in equal volumes. Then, 2 mL of 3-aminopropyltriethoxysilane (KH550) was added for end capping. The product from the previous step was then added to quaternize the polyurethane backbone by grafting antifouling groups (mass ratio 1:10) to obtain sample C.

[0067] 1 g of polydimethylsiloxane was diluted in a 10 g mixture of xylene, acetone, and methyl ethyl ketone (mass ratio 1:10). 0.02 g of methyltriacetoxysilane (METES) and 0.1 g of dibutyltin laurylate (DBTDL) were added, and the mixture was stirred at 25°C for 30 min. Then, 1 g of sample C, BYK140 dispersant, F370 leveling agent, and A-065 defoamer were added to the mixture, and stirred until homogeneous to form a homogeneous mixture. The amount of dispersant added was 0.5% of the mass of sample C, the amount of leveling agent added was 0.002% of the mass of sample C, and the amount of defoamer added was 0.002% of the mass of sample C. The mixture was then placed in a vacuum oven and vacuum-evacuated to remove air bubbles.

[0068] The mixture is brushed onto a carbon steel substrate and cured at room temperature for 7 days to obtain an anti-fouling coating with a thickness of 200 mm. Example 6

[0069] 11.1 mL of carvacrol, 54 mg of 4-dimethylaminopyridine (DMAP), and 5.86 mL of pyridine were added to 100 mL of anhydrous diethyl ether and cooled to 0 °C in an ice bath. Then, 7.56 mL of bromoacetyl bromide was slowly added dropwise and reacted for 16 h. The liquid phase was dried on a rotary vacuum evaporator, and the product was separated by column chromatography (eluting with a mixture of ethyl acetate, butyl acetate, and n-hexane and n-octane). The obtained product was then vacuum dried. 860 mL of N-methyldiethanolamine and 2.17 g of isophorone diisocyanate were subjected to a polycondensation reaction (molar ratio 1:1.3), with 0.05 g of dibutyltin laurate (DBTDL) as a catalyst. The reaction solution was 30 mL of N,N-dimethylformamide, and then 2 mL of 3-aminopropyltriethoxysilane (KH550) was added for end-capping. Then, the product from the previous step was added to quaternize the polyurethane backbone by grafting antifouling groups (mass ratio 1:5) to obtain sample D.

[0070] Then, N,N-dimethylformamide dispersant, MONENG-1080 leveling agent, and A-141 defoamer were added to sample D and stirred evenly to form a mixture. The amount of dispersant added was 0.5% of the mass of sample D, the amount of leveling agent added was 0.002% of the mass of sample D, and the amount of defoamer added was 0.002% of the mass of sample D. Then, the sample was placed in a vacuum oven and vacuumed to remove air bubbles.

[0071] The mixture is brushed onto a carbon steel substrate and cured at room temperature for 7 days to obtain an anti-fouling coating with a thickness of 100 mm. Example 7

[0072] 22.1 g capsaicin, 54 mg 4-dimethylaminopyridine (DMAP), and 5.86 mL pyridine were added to 100 mL anhydrous diethyl ether and cooled to 0 °C in an ice bath. Then, 7.56 mL of bromoacetyl bromide was slowly added dropwise, and the reaction proceeded for 16 h. The liquid phase was dried on a rotary vacuum evaporator and then dissolved in a mixed solvent of ethanol, n-propanol, and n-octanol. The product was recrystallized in water and then dried under vacuum. 860 mL of N-methyldiethanolamine and 2.17 g of isophorone diisocyanate underwent a polycondensation reaction (molar ratio 1:1.3) with 0.05 g dibutyltin laurylate (DBTDL) as a catalyst. The reaction solution was 30 mL of N,N-dimethylformamide. 2 mL of 3-aminopropyltriethoxysilane (KH550) was added for end-capping, followed by the dried product. Quaternization grafting of antifouling groups (mass ratio 1:5) was then performed on the polyurethane backbone to obtain sample E.

[0073] Then, add BYK142 dispersant, Solvesso150 leveling agent and A-530 defoamer to sample E and stir until a mixture is formed. The amount of dispersant added is 0.5% of the mass of sample E, the amount of leveling agent added is 0.002% of the mass of sample E, and the amount of defoamer added is 0.002% of the mass of sample E. Then, place it in a vacuum oven to remove air bubbles.

[0074] The mixture is brushed onto a carbon steel substrate and cured at room temperature for 7 days to obtain an anti-fouling coating with a thickness of 100 mm. Example 8

[0075] The coatings prepared in Examples 1-3 were evaluated as follows:

[0076] Referring to the standard GB / T5210-2006 "Paints and Varnishes - Pull-off Adhesion Test", a special coating adhesion tester was used with a spindle diameter of 20 mm and a measurement range of 0-24 MPa. The adhesion of three samples from the same batch was tested, and the average value was taken as the final result.

[0077] The two coating samples, before and after modification, were immersed in a culture medium containing fluorescently labeled bovine serum albumin. After 12 hours of light exposure and 12 hours of dark incubation, the coating samples were removed, the surface residual culture medium was rinsed with distilled water, and after drying, the adhesion area of ​​protein on the coating surface was observed and measured under a fluorescence microscope.

[0078] Reference Figure 3 It can be seen that the coatings prepared in Examples 1-3 can slowly hydrolyze in the environment to release salicylic acid for sterilization and antifouling. Furthermore, in Example 3, due to the higher proportion of grafted antifouling groups, the concentration of released salicylic acid is higher, resulting in better antibacterial and antifouling effects. Figure 4 and Figure 5 It is known that the coating prepared in this invention has excellent anti-protein adhesion and antibacterial ability, and the effect increases with the increase of the proportion of grafted antifouling groups. Example 9

[0079] According to the evaluation method of Example 8, Examples 6 and 7 were evaluated as follows:

[0080] The evaluation results show that using carvacrol or capsaicin as a biomass-based antifouling agent has the same performance as using salicylic acid as a biomass-based antifouling agent.

[0081] Biomass-based antifouling agents, as the name suggests, utilize antifouling agents or derivatives derived from biomass and incorporate them into antifouling coatings, such as capsaicin, carvacrol, and salicylic acid. These biomass antifouling agents have minimal environmental toxicity during service and offer significant antifouling effects. For example, capsaicin possesses excellent antioxidant properties and exhibits significant inhibitory effects on both Gram-negative and Gram-positive bacteria, and has been incorporated into organic coatings as an antifouling agent.

[0082] The coating formed by this invention has a hydrolyzable, leaching-type bactericide and an exposed, fixed antifouling group after hydrolysis. The antifouling and anti-scaling coating of this invention uses a matrix such as polyurethane, polydimethylsiloxane, or epoxy polymer, which is modified by esterification-quaternization reaction through distributed grafting. Biomass-based antifouling agents such as capsaicin, carvacrol, and salicylic acid, or esterified with haloacyl halides (preferably bromoacetyl bromide), are then grafted onto the polyurethane, polydimethylsiloxane, or epoxy polymer backbone through a quaternization reaction.

[0083] The grafted and modified polymer was dissolved in a coating thinner and sprayed onto a metal substrate for room temperature curing. When the coating was immersed in oilfield wastewater, the phenolic ester bonds on the coating surface hydrolyzed upon contact with the aqueous solution, initially releasing a biomass-based antifouling agent to achieve leaching-type antifouling. After hydrolysis, betaine-type quaternary ammonium salt groups were exposed on the coating surface. At this point, the coating, as a non-leaching cationic polymer surface, achieved contact sterilization and scale prevention. The prepared biomass-based antifouling coating kills microorganisms under the scale through the release of leaching biomass bactericides, which are then detached along with the scale layer. In the later stages of the coating's service life, contact sterilization is achieved through the immobilized quaternary ammonium salt groups, thus achieving green and long-lasting antifouling and scale prevention.

Claims

1. A method for preparing an antifouling and scale-inhibiting coating for oil-water gathering and transportation pipelines, characterized in that, Includes the following steps: (1) The biomass-based antifouling agent undergoes an esterification reaction with a haloacyl halide; (2) The antifouling agent after esterification in step (1) is grafted onto the polymer backbone through a quaternization reaction; (3) Dissolve the grafted and modified polymer from step (2) into the coating thinner; (4) Add dispersant, defoamer and leveling agent to the diluted polymer obtained in step (3); (5) Apply the mixture obtained in step (4) to the surface of the substrate and cure at room temperature to obtain an antifouling and scale-inhibiting coating. The biomass-based antifouling agent in step (1) is one or more of salicylic acid, carvacrol and capsaicin; In step (1), the halogenated acyl halide is bromoacetyl bromide; The polymer in step (2) is polyurethane; the synthesis route of the polyurethane is as follows: N-methyldiethanolamine and isophorone diisocyanate are subjected to polycondensation reaction, dibutyltin laurate is used as catalyst, nitrogen gas is used for protection, N,N-dimethylformamide is used as solvent, and 3-aminopropyltriethoxysilane is added for end capping.

2. The method for preparing an antifouling and scale-inhibiting coating for oil-water gathering and transportation pipelines according to claim 1, characterized in that, In step (2), the mass ratio of the polymer to the esterified antifouling agent is (1:3) to (1:10).

3. The method for preparing an antifouling and scale-inhibiting coating for oil-water gathering and transportation pipelines according to claim 1, characterized in that, The mass ratio between the grafted and modified polymer and the coating thinner in step (3) is (1:2) to (1:10).

4. The method for preparing an antifouling and scale-inhibiting coating for oil-water gathering and transportation pipelines according to claim 1, characterized in that, The paint thinner in step (3) is one or more of xylene, acetone and methyl ethyl ketone.

5. The method for preparing an antifouling and scale-inhibiting coating for oil-water gathering and transportation pipelines according to claim 1, characterized in that, The dispersant in step (4) is one or both of BYK140 and BYK142.

6. The method for preparing an antifouling and scale-inhibiting coating for oil-water gathering and transportation pipelines according to claim 1, characterized in that, The defoamer used in step (4) is A-530.

7. The method for preparing an antifouling and scale-inhibiting coating for oil-water gathering and transportation pipelines according to claim 1, characterized in that, The leveling agent used in step (4) is F370, MONENG-1080, or Solvesso 150.

8. The method for preparing an antifouling and scale-inhibiting coating for oil-water gathering and transportation pipelines according to claim 1, characterized in that, The substrates used in step (5) include metal, glass, and plastic.

9. A method for preparing an antifouling and scale-inhibiting coating for oil-water gathering and transportation pipelines according to claim 1, characterized in that, The coating thickness in step (5) is between 20 μm and 200 μm.

10. A method for preparing an antifouling and scale-inhibiting coating for oil-water gathering and transportation pipelines according to claim 1, characterized in that, The coating process in step (5) includes brushing, dipping, spraying, and spraying.

11. A method for preparing an antifouling and scale-inhibiting coating for oil-water gathering and transportation pipelines according to claim 1, characterized in that, The biomass-based antifouling agent has a mass content of 5% to 50% in the final coating.

12. The method for preparing an antifouling and scale-inhibiting coating for oil-water gathering and transportation pipelines according to claim 1, characterized in that, The basic process flow of the esterification reaction of the biomass-based antifouling agent using carvacrol is as follows: carvacrol, 4-dimethylaminopyridine, and pyridine are added to anhydrous diethyl ether and cooled in an ice bath, followed by slow dropwise addition of bromoacetyl bromide. After liquid phase drying, the product is separated by column chromatography and eluted with a mixture of ethyl acetate, butyl acetate, n-hexane, and n-octane. The obtained product is then vacuum dried.

13. The method for preparing an antifouling and scale-inhibiting coating for oil-water gathering and transportation pipelines according to claim 1, characterized in that, The basic process flow of the esterification reaction when the biomass-based antifouling agent uses capsaicin is as follows: capsaicin, 4-dimethylaminopyridine, and pyridine are added to anhydrous diethyl ether and cooled in an ice bath, followed by slow dropwise addition of bromoacetyl bromide for reaction. After liquid phase drying, the product is dissolved in a mixed solvent of ethanol, n-propanol, and n-octanol, recrystallized in water, and the resulting product is then vacuum dried.

14. A fouling and scale-inhibiting coating for oil-water gathering and transportation pipelines, characterized in that, The antifouling and scale-inhibiting coating is prepared by the method described in any one of claims 1-13 for preparing an antifouling and scale-inhibiting coating for oil-water gathering and transportation pipelines.

Images