Four-component oleophobic coatings, coatings and their applications

Abstract

This invention specifically relates to a four-component oleophobic coating, its application, and the following: The four-component oleophobic coating uses carbon nitride particles with high hardness and wear resistance, and silicon carbide particles with good chemical stability as fillers. The fillers are ensured to have different particle sizes and are blended in a specific ratio. Through the intercalation of particles of different sizes, a coating with suitable roughness and abundant porosity is formed, improving the hydrophilicity and oleophobic effect in aquatic environments. Simultaneously, the intercalation of particles of different sizes improves anchoring within the matrix, enhancing the coating's wear resistance. Furthermore, the fillers are dispersed in the matrix in different proportions to form component A and component B. Component A has a high concentration of filler, while component B has a low concentration. This ensures the coating's stable oleophobic effect while also providing stronger adhesion, making it more suitable for high-water-content, low-temperature gathering and transportation processing conditions.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field surface engineering technology, specifically to a four-component oleophobic coating, coating layer and its application. Background Technology

[0002] "Unheated oil gathering" is a novel technology for gathering waxy crude oil, which has shown significant effectiveness in reducing investment, energy consumption, and operating costs. In recent years, the promotion of unheated gathering and transportation technology has intensified, with the oil gathering temperature continuously decreasing and even breaking through the limitations of the freezing point. Under low-temperature conditions, the oil phase gels, and wax crystals and water droplets interact at the oil-water interface to form wax crystal-water droplet aggregates. These aggregates encapsulate the oil phase, forming solidified oil clumps. These solidified oil clumps have increased adhesion to gathering and transportation pipelines and equipment components, which can cause pipe blockage and adversely affect the dehydration process after the produced fluid enters the station. Heating the produced fluid before it enters the station can alleviate this problem, but this method is not only complex but also requires a large amount of energy to heat the water phase. These problems seriously restrict the comprehensive and in-depth promotion of low-temperature gathering and transportation technology. Oleophobic coatings are a type of superwetting material. By using functional oleophobic coatings to coat the substrate, the adhesion of oil clumps to production facilities can be reduced, and the resistance of produced fluid collection and transportation can be reduced. This is expected to solve the above problems. Moreover, oleophobic functional coatings have become a popular approach because they do not require additional energy input, do not require complex equipment, and are easy to maintain.

[0003] Currently, the anti-crude oil adhesion properties of oleophobic coatings have been preliminarily explored. For superwetting surface coatings intended for oleophobic applications, most are oleophobic surfaces in the air. According to Young's model theory, the surface energy of a solid must be less than or equal to one-quarter of the surface tension of the liquid to achieve intrinsic hydrophobicity. However, most organic liquids have very low surface tensions (mostly between 20 and 40 mN / m), making suitable coating materials even scarcer. Among various materials, fluoropolymers have the lowest surface tension, as low as around 20 mN / m. Therefore, fluorides are currently often used as low-surface-energy coatings for modification. However, commercially available fluoropolymers, such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and perfluoropropylene (PFNP), are expensive, significantly limiting the widespread adoption of oleophobic coatings. Furthermore, fluorinated substances gradually decompose within the coating or are lost under external forces. For example, the shear friction generated during the pressurized shear flow of produced media on the coating surface causes the loss of surface fluorinated substances, weakening the oleophobic effect. In addition, the biotoxicity and environmental pollution associated with fluorinated substances also hinder their widespread application. In addition, the oleophobic coatings currently used in the air environment also have problems such as insufficient adhesion to the substrate, poor wear resistance of the coating itself, low mechanical / chemical stability, and short service life.

[0004] Oil well produced fluid gathering and processing involves typical multiphase flow processes. If oleophobic coatings are used to coat the gathering pipelines and in-station processing equipment, the complex and variable service environment of the coatings presents a significant challenge to the development of adaptable oleophobic coatings. Furthermore, the uncertainties in the physicochemical properties of crude oil itself, such as viscosity, pour point, chemical composition, and pH value, further complicate coating performance and lifespan. More seriously, most major oilfields have now entered a high water-cut stage, and the flow and physical properties of the produced fluids have changed significantly. Existing fluorinated modified oleophobic coatings for air environments are no longer suitable for high water-cut conditions. Therefore, developing hydrophilically modified oleophobic coatings for high water-cut conditions to meet the oleophobic requirements of produced fluids under these conditions is an urgent technical problem to be solved. Summary of the Invention

[0005] This invention provides a four-component oleophobic coating. The coating has good hydrophilic and oleophobic effects and good chemical stability, and can be used in equipment for the high water content and low temperature gathering and transportation of oil well produced fluids.

[0006] This invention provides an oleophobic coating, which is a hydrophilic-oleophobic coating. It forms a water film with strong anti-disturbance ability, has good oleophobic effect in aquatic environments, and has excellent overall performance.

[0007] The present invention also provides an oil and gas equipment for high water content and low temperature gathering and transportation processing conditions. This equipment can effectively reduce the adhesion of oil clumps to production facilities and reduce the resistance of produced fluid gathering and transportation.

[0008] The present invention achieves the above-mentioned technical objectives through the following technical solutions:

[0009] This invention provides a four-component oleophobic coating, comprising component A, component B, component C, and component D;

[0010] Component A: formed by fillers dispersed in a matrix, the fillers including titanium nitride particles and silicon carbide particles, with the silicon carbide particles having a larger particle size than the carbon nitride particles, and the mass ratio of carbon nitride particles to silicon carbide particles being 1:(2-5). The matrix includes a binder and a solvent, with the mass ratio of fillers to binders being 4-6:10.

[0011] Component B: Component B uses the same raw materials as Component A, but the difference is that the mass ratio of filler to binder is 1-3:10.

[0012] Component C: Component C is the same matrix as component A;

[0013] Component D: Curing agent.

[0014] In the four-component oleophobic coating described above, the titanium nitride particles in the filler have a particle size of 200-300 nm, and the silicon carbide particles have a particle size of 300-400 nm.

[0015] In the four-component oleophobic coating described above, the mass ratio of binder in the matrix of components A, B, and C is 10-60%.

[0016] The four-component oleophobic coating described above uses an adhesive that is one or a combination of epoxy resin and acrylic resin.

[0017] The four-component oleophobic coating described above uses isophorone diamine and hexamethylene diisocyanate as curing agents, or a combination of two of them.

[0018] The four-component oleophobic coating described above uses epoxy resin and acrylic resin as binders with a volume ratio of (70-85):(60-70).

[0019] The four-component oleophobic coating described above uses isophorone diamine as the curing agent.

[0020] The four-component oleophobic coating described above consists of titanium nitride particles and silicon carbide particles, which are prepared into suspensions by ethanol, mixed, and then further dried and dispersed in the matrix.

[0021] The present invention also provides a method for preparing the above-mentioned four-component oleophobic coating. The method for preparing titanium nitride is as follows: titanium tetrachloride gas and ammonia gas are supplied in a stoichiometric ratio of 1:4 or an excess of ammonia gas, and reacted at 900-1150℃ for 2-4 hours. After cooling, the mixture is separated, ground and sieved to obtain titanium nitride particles of 200-300nm.

[0022] The preparation method of silicon carbide is as follows: prepare a solution of tetraethoxysilane and ethanol in a volume ratio of 1:(10-14), add ammonia dropwise while stirring at 300-800 rpm, adjust the pH of the solution to 8.4-10.6, and continue stirring at 50±5℃ to allow the tetraethoxysilane to undergo hydrolysis and condensation to generate a silica sol precursor solution.

[0023] The above silica precursor solution was added to a 50-60 mmol / L polyvinyl alcohol organic carbon source solution and mixed. The mixture was stirred at 80-95℃ for 3-3.5 hours to form a silicon and carbon composite gel. The volume ratio of the precursor solution to the organic carbon source solution was (1-3):(3-1).

[0024] The silicon and carbon composite gel was dried at 70-100℃ to remove solvent and moisture. It was then pre-carbonized and heated to 800-930℃ under an inert atmosphere and held for 3-4 hours. After further separation and purification, it was ground and sieved to obtain 300-400nm nanoscale silicon carbide particles.

[0025] According to the preparation method described above, the pre-carbonization treatment method in the silicon carbide preparation process is: treatment at 300-350℃ for 1-4 hours in an inert atmosphere.

[0026] The present invention also provides an oleophobic coating, which is formed by applying the above-mentioned oleophobic coating onto a substrate, wherein the bottom layer is coated with a mixture of components C and D, the middle layer is coated with a mixture of components B and D, and the top layer is coated with a mixture of components A and D; wherein, during coating, components A, B, C and D are all mixed in a mass ratio of 10:(1-2).

[0027] The present invention also provides an oil and gas equipment for high water content and low temperature gathering and transportation processing, wherein at least the side in contact with crude oil has the above-mentioned oleophobic coating.

[0028] This invention uses carbon nitride particles, which possess high hardness and wear resistance, and silicon carbide particles, which exhibit good chemical stability, as fillers. The two particles are matched with different sizes in a specific ratio. Through the intercalation of particles of different sizes, a coating with suitable roughness and abundant porosity is formed. The abundant porosity provides high capillary force, resulting in strong resistance to water film disturbance and improved hydrophilicity and oleophobicity in aquatic environments. Simultaneously, the intercalation of particles of different sizes enhances anchoring within the matrix, strengthening the coating's wear resistance. Further, these particles are dispersed in the matrix in different proportions to form components A and B. Component A has a high concentration of filler, exhibiting superhydrophilic characteristics, resulting in excellent oleophobic properties in aquatic environments. Component B has a low concentration of filler, exhibiting some hydrophilic characteristics, further enhancing the oleophobic effect. Component C is sprayed onto the bottom as a matrix layer, enhancing the coating's adhesion to the substrate through van der Waals forces, hydrogen bonds, covalent bonds, and mechanical bonding, achieving stronger adhesion and ensuring stable oleophobic performance. These synergistic effects ensure that the coating is more suitable for high-water-content, low-temperature gathering and transportation processing conditions.

[0029] The oleophobic coating provided by this invention is formed by coating the above-mentioned coating material, and has good oleophobic effect and excellent wear resistance and corrosion resistance.

[0030] The present invention provides an oil and gas equipment for high water content and low temperature gathering and transportation conditions. This equipment can effectively reduce the adhesion of oil clumps to production facilities and reduce the resistance of produced fluid gathering and transportation. Attached Figure Description

[0031] Figure 1 The image shows the SEM image of the titanium nitride-silicon carbide filler particles in the composite filler system of Example 1.

[0032] Figure 2 This is an example of the oil droplet contact angle test results for the substrate coated in Example 1;

[0033] Figure 3This is an example of the droplet roll-off angle test results for the substrate coated in Example 1;

[0034] Figure 4 Example of oil droplet contact angle test results for a substrate coated with a commercially available conventional fluoride coating as shown in Comparative Example 1;

[0035] Figure 5 A system for simulating the adhesion of oleophobic properties in a stirred tank. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0037] This invention provides a four-component oleophobic coating, which comprises four components: component A, component B, component C, and component D.

[0038] Component A: formed by fillers dispersed in a matrix, the fillers including titanium nitride particles and silicon carbide particles, with the silicon carbide particles having a larger particle size than the carbon nitride particles, and the mass ratio of carbon nitride particles to silicon carbide particles being 1:(2-5); the matrix includes a binder and a solvent, with the mass ratio of filler to binder being 4-6:10.

[0039] Component B: Component B uses the same raw materials as Component A, wherein the mass ratio of filler to binder is 1-3:10;

[0040] Component C: Component C is the same matrix as component A;

[0041] Component D: Curing agent.

[0042] This invention uses carbon nitride and silicon carbide particles as fillers, ensuring that the silicon carbide particles are larger than the carbon nitride particles and controlling the ratio of the two within a specific range. This ensures that small particles are evenly distributed in the gaps between the stacked large silicon carbide particles, without completely covering the large particles. The large particles provide anchor points and a framework for the small particles, while the small particles provide richer porosity and micro-roughness for the large particles. Through the interlocking of particles of different sizes, a coating with suitable roughness and abundant porosity is formed. The abundant porosity provides high capillary force, resulting in strong resistance to water film disturbance and improved hydrophilicity and oleophobicity in aquatic environments. Simultaneously, the interlocking of particles of different sizes enhances anchoring within the matrix, strengthening the coating's wear resistance. In addition, carbon nitride filler particles have high hardness and wear resistance, while high water content produced fluids undergo flow shearing during gathering and transportation, which can protect the coating and prolong the oleophobic effect. Silicon carbide filler particles have good chemical stability, are very stable in most acid and alkaline environments, have excellent oxidation and corrosion resistance, and also have a certain degree of toughness to resist impact. The synergistic effect of the two ensures that the coating is more suitable for high water content and low temperature gathering and transportation conditions.

[0043] The components are further dispersed in the matrix in different proportions to form components A and B. During spraying, component A, which contains a high concentration of filler, is sprayed on the top layer, and component B, which contains a low concentration of filler, is sprayed in the middle. The high concentration of filler in component A exhibits superhydrophilic characteristics, giving the coating excellent oleophobic effect in aquatic environments. The low concentration of filler in component B has certain hydrophilic characteristics, which enhances the oleophobic effect of the coating. Component C is sprayed at the bottom as a matrix layer, which can enhance the van der Waals forces, hydrogen bonds, covalent bonds, and mechanical interlocking of the coating with the substrate, achieving stronger adhesion and ensuring that the coating stably performs its oleophobic function.

[0044] Studies have found that coatings perform better when the particle size of carbon nitride particles in the filler is 200-300 nm and the particle size of silicon carbide particles is 300-400 nm.

[0045] In this invention, as described above, large silicon carbide particles provide anchor points and a framework for small particles, while small particles provide richer porosity and micro-roughness for large particles, ensuring a more stable water layer and greater capillary force. Controlling the mass ratio of the two to 1:(2-5) ensures that small particles are evenly distributed in the gaps between the stacked large silicon carbide particles, and that the large particles are not completely covered by the small particles. When the mass ratio is 1:3, the coating formed by the paint exhibits even better performance.

[0046] The binder not only enhances the bonding force between fillers through adhesion but also improves the overall bonding force between the coating and the substrate. Simultaneously, the substrate, as the main framework of the coating, also needs to possess certain mechanical strength, hardness, and toughness. In this invention, resin is generally used as the binder, and the specific type is not limited. For example, epoxy resin, acrylic resin, waterborne polyurethane, polyvinyl alcohol resin, melamine resin (MF resin), or polyamide polyamine epichlorohydrin (PAE) resin can be selected. More specifically, hydroxyl acrylic resins can be selected from Joucryl 581, RT3470, SSZ-174, etc.; waterborne polyurethanes can be selected from F0401, PU7310, waterborne 951, etc.; polyvinyl alcohol resins can be selected from PVA1788, PVA1799, PVAL100-37H, etc.; melamine resins can be selected from CYMEL 325, CYMEL 327, etc.; and polyamide polyamine epichlorohydrin (PAE) resins can be selected from PAE1201U, etc.

[0047] The solvent in the matrix can be any conventional solvent used in this field, and the specific solvent can be adjusted according to the type of resin selected. For example, water, dimethyl sulfoxide, dimethylformamide, toluene, xylene, cyclohexane, various alcohols, DMF, NMP, THF, ethyl acetate, butyl acetate, etc., can be used. The binder content in the matrix is ​​typically 10-60% by mass.

[0048] When using spray coating, to accelerate the transformation of the coating from liquid to solid state, improve construction efficiency, and shorten drying time, thus enabling the coating to reach its final performance faster, different curing agents are generally selected for different substrates. For example, TDI (toluene diisocyanate), MDI (diisocyanate), HDI (hexamethylene diisocyanate), and IPDI (isophorone diisocyanate) can be chosen. After the curing agent is determined, its dosage is adjusted to achieve optimal crosslinking performance and avoid under-cured or under-crosslinked states.

[0049] Studies have found that coatings exhibit superior performance when the binder is a combination of one or both epoxy resin and acrylic resin. In particular, when the binder is a blend of epoxy and acrylic resin in a volume ratio of (70-85):(60-70), it not only adjusts the viscosity of the coating components, ensuring good flowability and uniformity during application, but also facilitates the bonding of other components in the coating into a cohesive whole, adhering to the surface of the substrate to form a uniform, continuous, and robust protective film. This provides protection for the substrate, and the coating also possesses higher toughness and strength, resulting in superior performance.

[0050] When the adhesive is epoxy resin and acrylic resin, the corresponding solvents can be dimethyl sulfoxide and dimethylformamide, and the curing agents can be isophorone diamine and hexamethylene diisocyanate.

[0051] In this invention, to avoid particle agglomeration and ensure uniform particle dispersion, a solvent that facilitates particle dispersion can be selected to disperse the particles, mix them, and then remove the solvent. For example, ethanol can be used as a solvent, and removal is simple. For instance, components A and B can be prepared by the following method: first, a titanium nitride particle suspension and a silicon carbide particle suspension are mixed to obtain a carbon nitride-silicon carbide composite system. After drying, a composite filler system with uniformly distributed carbon nitride-silicon carbide particles is obtained. Then, the composite filler system is mixed with the matrix in a certain proportion to obtain the final product.

[0052] Furthermore, the composite filler system can be mixed and dispersed in the matrix using ultrasonic dispersion, which can ensure more uniform particle dispersion. For example, ultrasonic dispersion with a power of 200-500W and a time of 20-40 minutes can be used.

[0053] In this invention, both carbon nitride particles and silicon carbide particles are commercially available or can be prepared in-house. When the above raw materials are obtained using in-house preparation methods, the carbon nitride particles and silicon carbide particles can be prepared using the following methods respectively:

[0054] Titanium nitride particles can be generated into spherical carbon nitride particles by chemical vapor deposition, as follows: titanium tetrachloride gas and ammonia gas are supplied at a stoichiometric ratio of 1:4 or with excess ammonia gas, and reacted at 900-1150℃ for 2-4 hours. After cooling, the mixture is separated, ground, and sieved to obtain titanium nitride particles of 200-300nm.

[0055] Silicon carbide can be prepared by the following method: a solution of tetraethoxysilane (TEOS) and ethanol in a volume ratio of 1:(10-14) is prepared, and ammonia is added dropwise under stirring at 300-800 rpm to adjust the pH of the solution to 8.4-10.6. The solution is then continuously stirred at 50±5℃ to allow the tetraethoxysilane to undergo hydrolysis and condensation, generating a silica sol precursor solution.

[0056] The above silica precursor solution was added to a 50-60 mmol / L polyvinyl alcohol organic carbon source solution and mixed. The mixture was stirred at 80-95℃ for 3-3.5 hours to form a silicon and carbon composite gel. The volume ratio of the precursor solution to the organic carbon source solution was (1-3):(3-1).

[0057] The silicon and carbon composite gel was dried at 70-100℃ to remove solvent and moisture. It was then pre-carbonized and heated to 800-930℃ under an inert atmosphere of nitrogen or argon and held for 3-4 hours. After further separation and purification, it was ground and sieved to obtain silicon carbide particles of 300-400nm.

[0058] Further research revealed that when titanium nitride and silicon carbide prepared using the above method were used as fillers, the overall performance of the coating was superior to that of commercially available fillers. This is likely due to the higher purity of the filler particles prepared using the above method.

[0059] The present invention also provides an oleophobic coating, which is formed by coating the above-mentioned oleophobic coating onto a substrate, wherein the bottom layer is coated with a mixture of components C and D, the middle layer is coated with a mixture of components B and D, and the top layer is coated with a mixture of components A and D. During coating, components A, B, C and D are all mixed in a mass ratio of 10:(1-2).

[0060] This invention also provides an oil and gas equipment for high water content and low temperature gathering and transportation operations, wherein at least the side in contact with crude oil has the aforementioned oleophobic coating. This equipment can effectively reduce the adhesion of oil clumps to the equipment and reduce the resistance to produced fluid gathering and transportation.

[0061] Understandably, when used in spraying, the hardener accelerates the transformation of the coating from a liquid to a solid state, improving application efficiency and shortening drying time, thus allowing the coating to reach its final performance more quickly. Generally, there is a suitable range of hardener dosage for a specific substrate to achieve optimal crosslinking performance and avoid under-cured or under-crosslinked states.

[0062] The present invention will now be described in detail with reference to specific embodiments.

[0063] Example 1

[0064] Preparation of titanium nitride particle packing: Liquid titanium tetrachloride was placed in a gasifier, and the temperature of the gasifier was set at 155℃ to vaporize the titanium tetrachloride into a gas. This gas was introduced into the reaction tube through a gas delivery system, and ammonia gas was also delivered into the reaction tube through a flow controller. The ratio of titanium tetrachloride to ammonia gas was controlled at a stoichiometric ratio of 1:4 to prevent the formation of by-products. The preheated muffle furnace reactor was set at a high temperature of 1000℃. Ammonia gas was first introduced to maintain a reducing atmosphere, and then titanium tetrachloride gas was gradually introduced. The two gases mixed and reacted in the reaction tube. The reaction time was maintained for 3.5 hours, and the gas supply was gradually shut off, allowing the reaction tube to cool naturally to room temperature. Care was taken not to cool it suddenly to avoid thermal stress causing the reaction tube to break. After cooling, the reaction tube was removed, and the titanium nitride particles were separated from the substrate using an ultrasonic cleaning method and collected. After further grinding, crushing, and sieving, carbon nitride particle powder with a particle size of 200-300 nm was obtained. Take out the above titanium nitride particles and disperse them in ethanol. Stir and disperse evenly (stirring speed controlled at 650 r / min, stirring time 22 min) to form a suspension for later use, with a concentration of about 30 g / L.

[0065] Preparation of silicon carbide particulate filler: A solution of tetraethoxysilane (TEOS) and ethanol at a volume ratio of 1:13 was prepared. Ammonia was added dropwise while stirring at 450 rpm to adjust the pH to 9.5. The solution was then continuously stirred at 50 ± 2 °C to allow the tetraethoxysilane to hydrolyze and condense, generating a silica sol precursor solution. In a beaker, the organic carbon source, polyvinyl alcohol, was dissolved in an appropriate amount of deionized water and completely dissolved under magnetic stirring to obtain a carbon precursor solution with a concentration of 55 mmol / L. 570 mL of the carbon precursor solution was added dropwise to 490 mL of the silicon precursor solution while continuously stirring (stirring speed controlled at 360 rpm) to ensure uniform mixing. The mixture was transferred to a lidded reaction flask and placed in a 92 °C water bath for 3 hours. During heating, the mixture gradually underwent polymerization and gelation reactions, forming a silicon-carbon composite gel. The formed gel was placed in a vacuum drying oven and dried at 70°C for several hours to remove solvent and moisture. The dried gel was then placed in a tube furnace and pre-carbonized at 320°C for 2 hours under an inert atmosphere to remove some organic components and increase silicon carbide formation. The pre-carbonized material was then placed in a high-temperature furnace and gradually heated to 920°C under an argon inert atmosphere, maintaining this temperature for 4 hours. Under these high-temperature conditions, the silicon precursor reacts with the carbon precursor to generate nanoscale silicon carbide particles. After carbonization, the furnace was allowed to cool naturally to room temperature.

[0066] The cooled product was placed in an ultrasonic cleaner, and an appropriate amount of anhydrous ethanol was added. The particles were dispersed by ultrasonic oscillation (ultrasonic power set to 100W). The dispersed suspension was placed in a centrifuge, and the silicon carbide particles were separated by centrifugation. Multiple centrifugations and washings were performed to remove unreacted precursors or byproducts. The separated silicon carbide particles were dried in a vacuum drying oven, then ground and sieved to obtain silicon carbide particles with a particle size of 300-400 nm. The separated silicon carbide particle powder was dispersed in ethanol and stirred until uniform (stirring speed controlled at 620 r / min, stirring time 35 min) to form a suspension for later use, with a concentration of 30 g / L.

[0067] Preparation of the titanium nitride-silicon carbide composite filler system: The above-mentioned titanium nitride suspension and silicon carbide suspension were mixed at a volume ratio of 1:3 and stirred to form a uniformly dispersed system for later use. The stirring speed was controlled at 220 r / min. After drying, a composite filler system with uniformly distributed titanium nitride and silicon carbide particles was obtained. Figure 1 Its SEM image.

[0068] Preparation of the mixed matrix: Dissolve 80 mL of solvent-based epoxy resin (purchased from Shenzhen Yoshida Chemical, brand: E-44S) in 210 mL of dimethyl sulfoxide, and dissolve 66 mL of acrylic resin liquid (purchased from Shanghai Jiushi Chemical, model: BR-116) in 110 mL of dimethylformamide to prepare separate matrix solutions. Mix the prepared epoxy resin and acrylic resin solutions and stir thoroughly (recommended stirring speed 350 r / min) to obtain the mixed matrix solution.

[0069] Component A: The prepared titanium nitride-silicon carbide composite filler system was blended into the mixed matrix solution, controlling the mass ratio of filler (titanium nitride + silicon carbide) to binder (i.e., epoxy resin + acrylic resin) to be 5:10. The mixture was ultrasonically dispersed in an ultrasonic disperser at a power of 200W for 30 minutes, ensuring the filler was uniformly dispersed in the matrix, thus obtaining a high-concentration component A.

[0070] Component B: The prepared titanium nitride-silicon carbide composite filler system was blended into the mixed matrix solution, controlling the mass ratio of filler (titanium nitride + silicon carbide) to binder (i.e., epoxy resin + acrylic resin) to be 2:10. The mixture was ultrasonically dispersed in an ultrasonic disperser at a power of 200W for 30 minutes, ensuring the filler was uniformly dispersed in the matrix, thus obtaining the low-concentration component B.

[0071] Component C: The epoxy resin + acrylic resin composite matrix is ​​prepared using the formulation and preparation method of Component A, which is Component C.

[0072] Component D: Isophorone diamine.

[0073] Example 2

[0074] Preparation of spherical titanium nitride particle packing: Liquid titanium tetrachloride was placed in a gasifier, and the temperature of the gasifier was set at 155℃ to vaporize the titanium tetrachloride into a gas. This gas was introduced into the reaction tube through a gas delivery system, and ammonia gas was also supplied to the reaction tube through a flow controller. The ratio of titanium tetrachloride to ammonia gas was controlled at a stoichiometric ratio of 1:4 (with a slight excess of ammonia gas) to prevent the formation of byproducts. The preheated muffle furnace reactor was set at a high temperature of 1100℃. Ammonia gas was first introduced to maintain a reducing atmosphere, and then titanium tetrachloride gas was gradually introduced. The two gases mixed and reacted in the reaction tube. The reaction time was maintained for 2.5 hours, and the gas supply was gradually shut off, allowing the reaction tube to cool naturally to room temperature. Sudden cooling was avoided to prevent thermal stress that could cause the reaction tube to rupture. After cooling, the reaction tube was removed, and the titanium nitride particles were separated from the substrate using ultrasonic cleaning. These particles were then collected, further ground, crushed, and sieved to obtain carbon nitride particle powder with a particle size of 200-300 nm. Take out the titanium nitride powder particles, disperse them in ethanol, and stir until evenly dispersed (stirring speed controlled at 670 r / min, stirring time 26 min) to form a suspension for later use, with a concentration of approximately 35 g / L.

[0075] Preparation of spherical silicon carbide particle filler: Prepare a solution of tetraethoxysilane (TEOS) and ethanol in a volume ratio of 1:10. Add ammonia dropwise while stirring at 600 rpm to adjust the pH of the solution to 9.0. Continue stirring at 50±2℃ to allow the tetraethoxysilane to undergo hydrolysis and condensation, generating a silica sol precursor solution.

[0076] In a beaker, polyvinyl alcohol, the organic carbon source, was dissolved in an appropriate amount of deionized water and completely dissolved under magnetic stirring (stirring speed controlled at 450 r / min) to a concentration of 58 mmol / L. 590 mL of the carbon precursor solution was added dropwise to 510 mL of the silicon precursor solution while continuously stirring (stirring speed controlled at 380 r / min) to ensure uniform mixing and form a homogeneous solution. The solution was transferred to a lidded reaction flask and placed in a 95°C water bath for 4 hours. During heating, the solution gradually underwent polymerization and gelation reactions, forming a silicon-carbon composite gel. The formed gel was placed in a vacuum drying oven and dried at 80°C for several hours to remove solvent and moisture. The dried gel was then placed in a tube furnace and heated to 320°C under an inert atmosphere for pre-carbonization treatment to remove some organic components and increase silicon carbide formation. The pre-carbonized material was then placed in a high-temperature furnace and gradually heated to 850°C under an argon inert atmosphere, maintaining this temperature for 3.8 hours. Under these high-temperature conditions, the silicon precursor reacts with the carbon precursor to generate nanoscale silicon carbide particles. After carbonization, the furnace is allowed to cool naturally to room temperature.

[0077] The cooled product was placed in an ultrasonic cleaner, and an appropriate amount of anhydrous ethanol was added. The particles were dispersed by ultrasonic oscillation (ultrasonic power set to 100W). The dispersed suspension was placed in a centrifuge, and the silicon carbide particles were separated by centrifugation. Multiple centrifugations and washings were performed to remove unreacted precursors or byproducts. The separated silicon carbide particles were dried in a vacuum drying oven, then ground and sieved to obtain silicon carbide particles with a particle size of 300-400 nm. The separated silicon carbide particle powder was dispersed in ethanol and stirred until uniform (stirring speed controlled at 660 r / min, stirring time 40 min) to form a suspension for later use, with a concentration of 35 g / L.

[0078] Preparation of the titanium nitride-silicon carbide composite filler system: The above-mentioned titanium nitride suspension and silicon carbide suspension were mixed at a volume ratio of 1:2 and stirred to form a uniformly dispersed system for later use. The stirring speed was controlled at 240 r / min. After drying, a composite filler system with uniformly distributed titanium nitride and silicon carbide particles was obtained.

[0079] Preparation of the mixed matrix: Dissolve 90 mL of epoxy resin liquid (purchased from Shenzhen Yoshida Chemical, brand: E-44S) in 230 mL of dimethyl sulfoxide, and dissolve 70 mL of acrylic resin liquid (ACUST 3958, solid content 50%) in 130 mL of dimethylformamide to prepare separate matrix solutions. Mix the prepared epoxy resin and acrylic resin solutions and stir thoroughly (recommended stirring speed 360 r / min) to obtain the mixed matrix solution.

[0080] Component A: The prepared titanium nitride-silicon carbide composite filler system was blended into the mixed matrix solution, controlling the mass ratio of (titanium nitride + silicon carbide) to binder (epoxy resin + acrylic resin) to be 5:10. The mixture was ultrasonically dispersed in an ultrasonic disperser at a power of 200W for 30 minutes, ensuring the filler was uniformly dispersed in the matrix, thus obtaining a high-concentration component A.

[0081] Component B: The prepared titanium nitride-silicon carbide composite filler system was blended into the mixed matrix solution, controlling the mass ratio of (titanium nitride + silicon carbide) to binder (epoxy resin + acrylic resin) to be 2:10. The mixture was ultrasonically dispersed in an ultrasonic disperser at a power of 200W for 30 minutes, ensuring the filler was uniformly dispersed in the matrix, thus obtaining the low-concentration component B.

[0082] Component C: The epoxy resin + acrylic resin composite matrix is ​​prepared using the formulation and preparation method of Component A, which is Component C.

[0083] Component D: Hexamethylene diisocyanate.

[0084] Example 3

[0085] The difference between this embodiment and Embodiment 1 is that both the titanium nitride particles and silicon carbide particles were purchased, with the titanium nitride (purchased from China Metallurgical Group) having a particle size of 250±40nm and the silicon carbide (purchased from China Metallurgical Research Institute) having a particle size of 350±40nm.

[0086] Example 4

[0087] The difference between this embodiment and Example 1 is that the matrix uses only epoxy resin (purchased from Shenzhen Yoshida Chemical, brand name: E-44S). The matrix preparation method is as follows: 144 mL of epoxy resin liquid is dissolved in 390 mL of dimethyl sulfoxide to obtain the matrix solution.

[0088] Example 5

[0089] The difference between this embodiment and Example 1 is that an equal mass of waterborne polyurethane F0401 is used instead of epoxy resin. The matrix preparation method is as follows: Dissolve 80 mL of waterborne polyurethane F0401 in 210 mL of water, and dissolve 66 mL of acrylic resin liquid (purchased from Shanghai Jiushi Chemical, model: BR-116) in 110 mL of dimethylformamide to prepare matrix solutions. Mix the prepared polyurethane and acrylic resin solutions and stir thoroughly (recommended stirring speed 350 r / min) to obtain a mixed matrix solution.

[0090] Component D is an isocyanate curing agent, specifically hexamethylene diisocyanate trimer (purchased from Bayer AG, Germany; product number: n3390).

[0091] Example 6

[0092] The difference between this embodiment and Embodiment 1 is that both the titanium nitride particles and silicon carbide particles were purchased, with the titanium nitride particles having a particle size of 450±40nm and the silicon carbide particles having a particle size of 650±40nm.

[0093] Comparative Example 1

[0094] A coating is formed by dissolving commercially available fluorinated polyhexafluoropropylene (French Arcoma polyvinylidene fluoride hexafluoropropylene copolymer, molecular weight 300,000) in NMP (N-methylpyrrolidone).

[0095] Performance testing:

[0096] The coatings obtained in the examples and the coatings in the comparative examples were sprayed onto the surface of steel plates, with an uncoated substrate used as a control. The macroscopic oil contact angle of the coatings to the solidified oil in an aqueous environment was measured using a contact angle meter. The overall water content of the test system was 80%, representing a high-water-content state, and the oil's pour point was 26°C. The adhesion force between the liquid and the surface was measured using a high-precision microelectromechanical balance system, and the bonding strength between the coating and the substrate was determined using the cross-cut adhesion test. Figure 5 The self-made stirred tank shown simulates oil droplet adhesion under shear conditions (rotation speed 300 r / min, temperature 21℃). The temperature is below the oil's pour point. Some results are as follows: Figure 2-4 As shown in Table 1, the data is as follows.

[0097] The coating application method in the embodiment is as follows: Before spraying, the mass ratio of components A, B, C and D is controlled to be 10:1. Then, they are physically blended and then sprayed onto the steel plate surface using a low-pressure, high-flow spray gun. The thickness of the top layer, intermediate layer and bottom layer is 3:6:10 (total thickness is 210 micrometers), that is, top layer: 10g filler + 20g matrix + 3g isophorone diamine; intermediate layer: 10g filler + 5g matrix + 6g isophorone diamine; bottom layer: 100g matrix + 10g isophorone diamine.

[0098] In the comparative example, the coating thickness was 210 micrometers.

[0099] Table 1

[0100]

[0101] The results above show that the coating prepared using the four-component oleophobic coating containing the specific filler of this invention exhibits superior hydrophilicity and oleophobicity in an aquatic environment, and also demonstrates high bonding strength with the substrate. Specifically, its oil contact angle in an aquatic environment can reach over 120°, its roll-off angle can reach below 21°, its adhesion force can reach below 40mN, and its bonding strength with the substrate can withstand over 400 peel cycles.

[0102] When the particle size of titanium nitride particles in the filler is controlled to be 200-300nm and the particle size of silicon carbide particles is 300-400nm, the oil contact angle in the water environment can reach more than 140°, the rolling angle can reach less than 12°, the adhesion force can reach less than 25mN, and the number of peeling cycles can reach more than 410.

[0103] When epoxy resin and acrylic resin are further selected as a binder, the oil contact angle in the water environment can reach more than 160° (meeting the superoleophobic standard), the roll-off angle can reach less than 10°, the adhesion force can reach less than 20mN, and the peeling cycle can reach more than 485 times.

[0104] Furthermore, the analysis of Examples 1, 2 and 3 shows that the filler prepared by the preparation method described in Examples 1 and 2 of this application has better performance than the filler that is purchased directly. The reason for this may be that the filler prepared by the method of this application has better purity, which makes the overall performance of the coating better.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A four-component oleophobic coating, characterized in that, Includes components A, B, C, and D; Component A: formed by fillers dispersed in a matrix, the fillers including titanium nitride particles and silicon carbide particles, with the silicon carbide particles having a larger particle size than the carbon nitride particles, and the mass ratio of carbon nitride particles to silicon carbide particles being 1:(2-5). The matrix includes a binder and a solvent, with the mass ratio of fillers to binders being 4-6:

10. Component B: Component B uses the same raw materials as Component A, but the difference is that the mass ratio of filler to binder is 1-3:

10. Component C: Component C is the same matrix as component A; Component D: Curing agent.

2. The four-component oleophobic coating according to claim 1 or 2, characterized in that, The titanium nitride particles in the filler have a particle size of 200-300 nm, and the silicon carbide particles have a particle size of 300-400 nm.

3. The four-component oleophobic coating according to claim 1 or 2, characterized in that, The binder accounts for 10-60% of the mass of the matrix in components A, B, and C.

4. The four-component oleophobic coating according to claim 1 or 2, characterized in that, The adhesive is one or a combination of two of epoxy resin and acrylic resin; and / or The curing agent is one or a combination of two of isophorone diamine and hexamethylene diisocyanate.

5. The four-component oleophobic coating according to claim 4, characterized in that, The adhesive is epoxy resin and acrylic resin in a volume ratio of (70-85):(60-70); and / or The curing agent is isophorone diamine.

6. The four-component oleophobic coating according to claim 1, characterized in that, Titanium nitride particles and silicon carbide particles were prepared into suspensions by ethanol, then mixed, further dried, and dispersed in the matrix.

7. The method for preparing the four-component oleophobic coating according to any one of claims 1-6, characterized in that, The preparation method of titanium nitride is as follows: titanium tetrachloride gas and ammonia gas are supplied in a stoichiometric ratio of 1:4 or with excess ammonia gas, and reacted at 900-1150℃ for 2-4 hours. After cooling, the mixture is separated, ground and sieved to obtain titanium nitride particles of 200-300nm. The preparation method of silicon carbide is as follows: prepare a solution of tetraethoxysilane and ethanol in a volume ratio of 1:(10-14), add ammonia dropwise while stirring at 300-800 rpm, adjust the pH of the solution to 8.4-10.6, and continue stirring at 50±5℃ to allow the tetraethoxysilane to undergo hydrolysis and condensation to generate a silica sol precursor solution. The above silica precursor solution was added to a 50-60 mmol / L polyvinyl alcohol organic carbon source solution and mixed. The mixture was stirred at 80-95℃ for 3-3.5 hours to form a silicon and carbon composite gel. The volume ratio of the precursor solution to the organic carbon source solution was (1-3):(3-1). The silicon and carbon composite gel was dried at 70-100℃ to remove solvent and moisture. It was then pre-carbonized and heated to 800-930℃ under an inert atmosphere and held for 3-4 hours. After further separation and purification, it was ground and sieved to obtain 300-400nm nanoscale silicon carbide particles.

8. The preparation method according to claim 7, characterized in that, In the preparation of silicon carbide, the pre-carbonization treatment method is as follows: treat at 300-350℃ for 1-4 hours in an inert atmosphere.

9. An oleophobic coating, characterized in that, The oleophobic coating is formed by applying the oleophobic coating according to any one of claims 1-8 onto a substrate, wherein the bottom layer is coated by mixing components C and D, the middle layer is coated by mixing components B and D, and the top layer is coated by mixing components A and D; wherein, during coating, components A, B, C and D are mixed in a mass ratio of 10:(1-2).

10. An oil and gas gathering and transportation system for high water content and low temperature processing conditions, characterized in that, At least the side that comes into contact with crude oil has the oleophobic coating as described in claim 9.

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