High-temperature and high-pressure resistant drag-reducing energy-saving heavy-duty anticorrosive coating and preparation method thereof

Abstract

The present application relates to the technical field of pipeline coating, in particular to a high-temperature and high-pressure resistant drag-reducing energy-saving heavy-duty coating and a preparation method thereof.The high-temperature and high-pressure resistant drag-reducing energy-saving heavy-duty coating provided by the present application forms an ultra-low-pore dense structure after curing, and polytetrafluoroethylene micro powder is moderately enriched on the surface and uniformly dispersed inside, thereby synergistically improving drag reduction and long-term corrosion resistance.

Description

Technical Field

[0001] This invention relates to the field of pipeline coating technology, specifically to a high-temperature, high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating and its preparation method. Background Technology

[0002] In energy transmission, municipal heating, and oil and gas extraction, long-distance metal pipelines are widely used to transport high-temperature and high-pressure water or steam. In these environments, with increasing service life, pipeline corrosion intensifies, the inner wall thins unevenly, pressure-bearing capacity decreases, and localized perforations and ruptures frequently lead to leaks. Therefore, using high-performance anti-corrosion coatings is essential to ensure safety.

[0003] In addition, the frictional resistance between the inner wall of the pipeline and the fluid is the main source of pumping energy consumption. Especially in long-distance transportation scenarios such as steam insulation pipelines, heating pipelines, and oilfield water injection pipelines, the proportion of resistance loss is significant. Reducing the friction coefficient of the inner wall of the pipeline has important industrial value for energy conservation and emission reduction.

[0004] Polytetrafluoroethylene (PTFE) is an ideal drag-reducing material due to its extremely low surface free energy, excellent chemical inertness, and thermal stability. Theoretically, low surface energy coatings can induce a boundary layer slip effect on the pipe wall surface, reducing wall shear forces and thus lowering friction loss. Epoxy resin is one of the most widely used anti-corrosion coatings in industry. It possesses advantages such as good resistance to chemical corrosion, good alkali resistance, low curing shrinkage, high bond strength, and excellent adhesion.

[0005] However, polytetrafluoroethylene (PTFE) has extremely low surface tension and poor compatibility with conventional epoxy matrix. This not only causes PTFE to spontaneously migrate to the surface within the conventional epoxy matrix, leading to coating delamination and easy coating failure, but also causes PTFE to agglomerate, forming countless tiny voids and weak interfaces inside the coating, thus failing to achieve long-term anti-corrosion effect. Summary of the Invention

[0006] To overcome the above problems, the present invention provides a high-temperature and high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating and its preparation method.

[0007] To achieve the above technical objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a high-temperature, high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating, the raw materials of which, by weight, comprise: The composition comprises 100-400 parts of epoxy resin, 50-200 parts of phenolic resin curing agent, 0.2-1.5 parts of curing accelerator, 5-40 parts of polytetrafluoroethylene micro powder, 200-600 parts of inorganic composite filler, and 5-50 parts of composite additives. The epoxy resin composition includes phenolic epoxy resin and bisphenol A epoxy resin. Inorganic composite packings include inorganic needle-shaped packings and inorganic spherical packings; Composite additives include leveling agents, degassing agents, defoamers, and adhesion promoters.

[0008] A second aspect of the present invention provides a method for preparing the high-temperature, high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating described in the first aspect, comprising the following steps: Weigh the raw materials according to the weight ratio, pour them into the premix container and mix well; The mixed raw materials are added to a twin-screw extruder for melt extrusion. The extrusion screw speed frequency of the extruder is 40~60 Hz, and the melt temperature of the extruder is controlled at 90~110℃. The extruded material is cooled by the pressure rollers, pressed into sheets, ground, and sieved to obtain a high-temperature, high-pressure, drag-reducing, energy-saving, heavy-duty anti-corrosion coating.

[0009] The beneficial effects of this invention are as follows: (1) The high-temperature and high-pressure drag-reducing, energy-saving, and heavy-duty anti-corrosion coating provided by this invention forms an ultra-low porosity and dense structure after curing. Furthermore, polytetrafluoroethylene (PTFE) micropowder is moderately enriched on the surface and uniformly dispersed internally, synergistically improving drag reduction and long-term corrosion resistance. Specifically, after curing, the high-temperature and high-pressure drag-reducing, energy-saving, and heavy-duty anti-corrosion coating exhibits a static contact angle with water (referring to GB / T 30693-2014 "Determination of Contact Angle of Plastic Films and Sheets" (static drop method)) ≥100° and a surface energy ≤38 mJ / m². 2 (Calculated using the OWRK method), the friction resistance coefficient is reduced by more than 10% compared to uncoated carbon steel, achieving significant energy-saving effects. After curing, the high-temperature, high-pressure drag-reducing, energy-saving, and heavy-duty anti-corrosion coating remained intact after being continuously immersed in pure water at 150℃ and 10MPa for 2000 hours, showing no blistering, peeling, or substrate corrosion. Both the blistering level and the area of ​​coating peeling met the requirements for high-pressure operating conditions.

[0010] (2) The high temperature and high pressure drag reduction energy-saving heavy anti-corrosion coating provided by the present invention has a glass transition temperature Tg≥160℃ after curing, and can withstand the extreme working condition of 150℃ for a long time. It does not soften, deform or creep at high temperature, thus having good high thermal stability.

[0011] (3) The high temperature and high pressure drag reduction energy-saving heavy-duty anti-corrosion coating provided by the present invention has excellent acid salt spray resistance after curing: after 1000 h of copper accelerated acetic acid salt spray test, there are no corrosion defects in the sprayed area of ​​the high temperature and high pressure drag reduction energy-saving heavy-duty anti-corrosion coating, and there are no abnormal failure phenomena in the whole. Attached Figure Description

[0012] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0013] Figure 1 The image shows the water contact angle of the high-temperature, high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating prepared in Example 1 after curing. Figure 2 The image shows the water contact angle after the wear resistance of the high-temperature, high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating prepared in Example 1 has been verified after curing. Detailed Implementation

[0014] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0015] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0016] In fields such as energy transmission, municipal heating, and oil and gas extraction, long-distance metal pipelines urgently need drag reduction and long-term corrosion protection.

[0017] Polytetrafluoroethylene (PTFE) is an ideal drag-reducing material due to its extremely low surface free energy, excellent chemical inertness, and thermal stability. Theoretically, low surface energy coatings can induce a boundary layer slip effect on the pipe wall surface, reducing wall shear forces and thus lowering friction loss. Epoxy resin is one of the most widely used anti-corrosion coatings in industry. It possesses advantages such as good resistance to chemical corrosion, good alkali resistance, low curing shrinkage, high bond strength, and excellent adhesion.

[0018] However, polytetrafluoroethylene (PTFE) has extremely low surface tension and poor compatibility with conventional epoxy matrix. This not only causes PTFE to spontaneously migrate to the surface within the conventional epoxy matrix, leading to coating delamination and easy coating failure, but also causes PTFE to agglomerate, forming countless tiny voids and weak interfaces inside the coating, thus failing to achieve long-term anti-corrosion effect.

[0019] The high-temperature and high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating provided by this invention forms an ultra-low porosity and dense structure after curing. The polytetrafluoroethylene micro powder is moderately enriched on the surface and uniformly dispersed inside, which synergistically improves drag reduction and long-term corrosion resistance.

[0020] This invention achieves an ultra-low porosity, dense structure through the precise matching of various inorganic composite fillers and the epoxy-phenolic curing equivalent. This is because: the combination of multiple inorganic composite fillers effectively eliminates macro / mesoscopic pores; and the precise matching of the epoxy-phenolic curing equivalent ensures optimal performance in terms of shrinkage, stress, and molecular integrity, preventing the generation of microscopic defects. Ultimately, this results in a coating porosity of Grade 1 after curing of the high-temperature, high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating, constructing a dense physical shielding layer.

[0021] In this invention, by controlling the ratio of phenolic epoxy resin and bisphenol A epoxy resin in the epoxy resin composition, the viscosity of the system can be altered, providing just the right amount of resistance to the migration of polytetrafluoroethylene (PTFE) and preventing its excessive accumulation. Simultaneously, by strictly limiting the equivalent ratio of epoxy groups in the epoxy resin composition to phenolic hydroxyl groups in the phenolic resin curing agent, the crosslinking density and rate are adjusted, thereby controlling the migration of PTFE. Furthermore, the combination of inorganic needle-like fillers and inorganic spherical fillers constructs a three-dimensional framework within the coating. This framework provides support and confinement space for the dispersed PTFE, not only limiting excessive migration of PTFE to the surface but also preventing severe internal agglomeration, thus achieving uniform dispersion of PTFE within the system.

[0022] Furthermore, adhesion promoters, namely silane coupling agents, can enhance the bonding between polytetrafluoroethylene and epoxy groups, effectively forming interfacial bridges and ensuring the bonding stability of the coating.

[0023] The high-temperature, high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating, after curing, exhibits a static contact angle with water (referencing GB / T 30693-2014 "Determination of Contact Angle of Plastic Films and Sheets" (static drop method)) ≥100°, and a surface energy ≤38 mJ / m². 2 (Calculated using the OWRK method), the friction resistance coefficient is reduced by more than 10% compared to uncoated carbon steel, achieving significant energy-saving effects. After curing, the high-temperature, high-pressure drag-reducing, energy-saving, and heavy-duty anti-corrosion coating remained intact after being continuously immersed in pure water at 150℃ and 10MPa for 2000 hours, showing no blistering, peeling, or substrate corrosion. Both the blistering level and the area of ​​coating peeling met the requirements for high-pressure operating conditions.

[0024] This invention achieves excellent high-temperature resistance in a high-temperature, high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating by controlling the ratio of phenolic epoxy resin to bisphenol A epoxy resin in the epoxy resin composition and strictly limiting the equivalent ratio of epoxy groups in the epoxy resin composition to phenolic hydroxyl groups in the phenolic resin curing agent. The cured coating exhibits a glass transition temperature (Tg) ≥ 160℃ and can withstand extreme working conditions up to 150℃ for extended periods. It shows no softening, deformation, or creep at high temperatures, thus demonstrating excellent thermal stability.

[0025] The high-temperature, high-pressure drag-reducing, energy-saving, and heavy-duty anti-corrosion coating provided by this invention exhibits excellent high-pressure resistance and hydrolysis resistance after curing. This is due to several factors: First, by controlling the ratio of phenolic epoxy resin and bisphenol A epoxy resin in the epoxy resin composition, and strictly limiting the equivalent ratio of epoxy groups in the epoxy resin composition to phenolic hydroxyl groups in the phenolic resin curing agent, a stable chemically inert network is formed. Second, the moderate enrichment of polytetrafluoroethylene (PTFE) micropowder on the surface prevents water molecules from wetting and spreading, effectively blocking the direct attack of high-pressure water on the coating surface. Third, the precise matching of epoxy-phenolic curing equivalents through the compounding of various inorganic composite fillers achieves an ultra-low porosity and dense structure. Consequently, after curing, the coating remains intact and undamaged after continuous immersion in pure water at 150℃ and 10MPa for 2000 hours, showing no blistering, peeling, or substrate corrosion. The blistering level and coating peeling area both meet the requirements of high-pressure operating conditions.

[0026] Furthermore, the high-temperature and high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating provided by this invention exhibits excellent acid salt spray resistance after curing. In a 1000-hour copper-accelerated acetic acid salt spray test, no corrosion defects were observed in the sprayed area of ​​the high-temperature and high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating, and no abnormal failure phenomena were observed overall.

[0027] The high-temperature, high-pressure drag-reducing, energy-saving, and heavy-duty anti-corrosion coating provided by this invention exhibits excellent wear resistance after curing. According to SY / T 0442-2020 "Technical Standard for Fusion-Bonded Epoxy Powder Inner Coating of Steel Pipelines," the abrasion loss is ≤0.08 g / cm³. 2 After the abrasion resistance test, the static water contact angle is ≥90°.

[0028] A first typical embodiment of the present invention provides a high-temperature, high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating, the raw materials of which include, by weight: The composition comprises 100-400 parts of epoxy resin, 50-200 parts of phenolic resin curing agent, 0.2-1.5 parts of curing accelerator, 5-40 parts of polytetrafluoroethylene micro powder, 200-600 parts of inorganic composite filler, and 5-50 parts of composite additives. The epoxy resin composition includes phenolic epoxy resin and bisphenol A epoxy resin. Inorganic composite packings include inorganic needle-shaped packings and inorganic spherical packings; Composite additives include leveling agents, degassing agents, defoamers, and adhesion promoters.

[0029] In one or more embodiments, the epoxy equivalent in the epoxy resin composition is 200~900 g / eq.

[0030] Preferably, in the epoxy resin composition, the epoxy equivalent of the phenolic epoxy resin is 200~230 g / eq, and the epoxy equivalent of the bisphenol A epoxy resin is 800~900 g / eq; the mass ratio of the phenolic epoxy resin to the bisphenol A epoxy resin is (1~3):1, preferably (2~2.5):1.

[0031] In one or more embodiments, the phenolic epoxy resin in the epoxy resin composition includes one or more of o-cresol epoxy resin, phenolic epoxy resin, or bisphenol A epoxy resin.

[0032] In one or more embodiments, the phenolic resin curing agent is one of linear phenolic resin, bisphenol A phenolic resin, or phenol-aralkyl phenolic resin.

[0033] In one or more embodiments, the hydroxyl equivalent of the phenolic resin curing agent is 100~120 g / eq.

[0034] In one or more embodiments, the equivalent ratio of epoxy groups in the epoxy resin composition to phenolic hydroxyl groups in the phenolic resin curing agent is (0.95~1.05):1.

[0035] In one or more embodiments, the curing accelerator includes one or more of 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, or benzyltriethylammonium chloride.

[0036] In one or more embodiments, the particle size of the polytetrafluoroethylene micro powder is 1~15 μm.

[0037] In one or more embodiments, the inorganic composite filler includes one or more of wollastonite, sepiolite, acicular mica, or potassium titanate whiskers.

[0038] Preferably, the inorganic needle-shaped filler has a particle size of 0.5~20 μm and an aspect ratio of (8~25):1.

[0039] In one or more embodiments, the inorganic composite filler includes one or more of the following: high-purity fused silica micro powder, spherical quartz powder, spherical alumina, or fumed silica.

[0040] Preferably, the particle size of the inorganic spherical packing is 0.5~15 μm.

[0041] In one or more embodiments, the mass ratio of inorganic spherical packing to inorganic needle packing in the inorganic composite packing is (2~5):1.

[0042] In one or more embodiments, the mass ratio of leveling agent, degassing agent, defoamer and adhesion promoter in the composite additive is (3~7):(2~4):(2~4):(3~7).

[0043] In one or more embodiments, the leveling agent in the composite additive includes an acrylate leveling agent.

[0044] In one or more embodiments, the degassing agent in the composite additive includes benzoin.

[0045] In one or more embodiments, the defoamer in the composite additive includes a polysiloxane defoamer.

[0046] In one or more embodiments, the adhesion promoter in the composite additive is a silane coupling agent; more preferably, the silane coupling agent is selected from one or more of γ-glycidoxypropyltrimethoxysilane (KH-560), γ-aminopropyltriethoxysilane (KH-550) or γ-methacryloyloxypropyltrimethoxysilane (KH-570).

[0047] In one or more embodiments, the high-temperature and high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating further includes a colorant; Preferably, the colorant is composed of titanium dioxide and conductive carbon black.

[0048] A second typical embodiment of the present invention provides a method for preparing the high-temperature, high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating described in the first aspect, comprising the following steps: Weigh the raw materials according to the weight ratio, pour them into the premix container and mix well; The mixed raw materials are added to a twin-screw extruder for melt extrusion. The extrusion screw speed frequency of the extruder is 40~60 Hz, and the melt temperature of the extruder is controlled at 90~110℃. The extruded material is cooled by the pressure rollers, pressed into sheets, ground, and sieved to obtain a high-temperature, high-pressure, drag-reducing, energy-saving, heavy-duty anti-corrosion coating.

[0049] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0050] In the following embodiments: o-cresol formaldehyde epoxy resin (epoxy equivalent of 215 g / eq) was purchased from Jinan Shengquan SQCN704H; Bisphenol A type epoxy resin (epoxy equivalent of 870 g / eq) was purchased from Gukdu Chemical KD-2012H in South Korea; Linear phenolic resin (hydroxyl equivalent 105 g / eq) was purchased from Jinan Shengquan PF8020; The acrylate leveling agent was purchased from BYK Chemicals (BYK-3932 P).

[0051] Example 1 1.1 High-temperature, high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating, the raw materials of which include, by weight: The composition comprises 150 parts epoxy resin, 65 parts phenolic resin curing agent, 0.4 parts curing accelerator, 20 parts polytetrafluoroethylene micro powder, 440 parts inorganic composite filler, 16 parts composite additives, and 13 parts colorant.

[0052] The epoxy resin composition consists of o-cresol epoxy resin and bisphenol A type epoxy resin, wherein the mass ratio of o-cresol epoxy resin to bisphenol A type epoxy resin is 2:1, the epoxy equivalent of o-cresol epoxy resin is 215 g / eq, and the epoxy equivalent of bisphenol A type epoxy resin is 870 g / eq.

[0053] The phenolic resin curing agent is a linear phenolic resin with a hydroxyl equivalent of 105 g / eq.

[0054] The curing accelerator is 2-methylimidazole.

[0055] The particle size of polytetrafluoroethylene micro powder is 5 μm.

[0056] The inorganic composite packing includes inorganic needle-shaped packing and inorganic spherical packing; the mass ratio of inorganic spherical packing to inorganic needle-shaped packing is 3.4:1. The inorganic needle-shaped packing is wollastonite, and the inorganic spherical packing is high-purity fused silica powder. The particle size of the inorganic needle-shaped packing is 15 μm, and the aspect ratio is 10:1; the particle size of the inorganic spherical packing is 15 μm.

[0057] The composite additives include leveling agents, degassing agents, defoamers, and adhesion promoters. The mass ratio of leveling agent, degassing agent, defoamer, and adhesion promoter is 5:3:3:5. Specifically, the leveling agent is an acrylic leveling agent, the degassing agent is benzoin, the defoamer is a polysiloxane defoamer, and the adhesion promoter is γ-glycidoxypropyltrimethoxysilane (KH-560).

[0058] The colorant is composed of titanium dioxide and conductive carbon black, with a mass ratio of titanium dioxide to conductive carbon black of 10:3.

[0059] 1.2 The preparation method of high temperature and high pressure drag reduction energy-saving heavy-duty anti-corrosion coating includes the following steps: Weigh the raw materials according to the weight ratio, pour them into the premix container and mix well; The mixed raw materials are added to a twin-screw extruder for melt extrusion. The extrusion screw speed frequency of the extruder is 50Hz, and the melt temperature of the extruder is controlled at 100℃. The extruded material is cooled by the pressure rollers, pressed into sheets, ground, and sieved to obtain a high-temperature, high-pressure, drag-reducing, energy-saving, heavy-duty anti-corrosion coating.

[0060] Example 2 2.1 High-temperature and high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating. Compared with Example 1, the raw materials are adjusted to 10 parts of polytetrafluoroethylene micro powder, and the rest of the formula is the same as in Example 1.

[0061] 2.2 The preparation method of the high temperature and high pressure drag reduction energy-saving heavy-duty anti-corrosion coating is the same as in Example 1.

[0062] Example 3 3.1 High-temperature and high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating. Compared with Example 1, the particle size of polytetrafluoroethylene micro powder is adjusted to 10 μm, and the rest of the formula is the same as that of Example 1.

[0063] 3.2 The preparation method of the high temperature and high pressure drag reduction energy-saving heavy-duty anti-corrosion coating is the same as in Example 1.

[0064] Comparative Example 1 Compared to Example 1, the coating does not contain polytetrafluoroethylene (PTFE) micropowder. The preparation method of the coating is the same as in Example 1.

[0065] Comparative Example 2 Compared to Example 1, the coating raw materials contain 45 parts of polytetrafluoroethylene micro powder, while the remaining formulation is the same as in Example 1. The preparation method of the coating is the same as in Example 1.

[0066] Comparative Example 3 (Affects on density and internal polytetrafluoroethylene uniformity) Compared to Example 1, the raw materials of the coating do not contain inorganic composite fillers. The preparation method of the coating is the same as in Example 1.

[0067] Comparative Example 4 (with a thicker enrichment layer) Compared to Example 1, the equivalent ratio of epoxy groups in the epoxy resin composition to phenolic hydroxyl groups in the phenolic resin curing agent in the raw materials of the coating is 0.8:1.

[0068] Comparative Example 5 (thinner enrichment layer) Compared to Example 1, the equivalent ratio of epoxy groups in the epoxy resin composition to phenolic hydroxyl groups in the phenolic resin curing agent in the raw materials of the coating is 1.2:1.

[0069] Experimental Example 1 The coatings prepared in Examples 1-3 and Comparative Examples 1-5 were subjected to performance tests: Sample substrates: Q235B carbon steel test plates and GB / T 8163 seamless steel pipes; the surface of the sample substrates was sandblasted to Sa2.5 grade with a surface roughness of 50 μm; electrostatic spraying was applied, and the dry film thickness was controlled at 300 μm according to GB / T 13452.2-2020 "Determination of Film Thickness of Paints and Varnishes"; curing conditions were 200℃ / 12min, followed by natural cooling to room temperature; three parallel samples were set up for each test, and the average value of the test data was taken.

[0070] Testing standards: Glass transition temperature Tg: GB / T 19466.2-2022; Bending performance: GB / T 6742-2007 (2mm mandrel); Adhesion: GB / T 9286-2021; Water contact angle: Refer to GB / T 30693-2014; Surface energy: Refer to OWRK method; High temperature and high pressure water resistance: GB / T 1763 (150℃ / 10MPa / 2000h); Copper accelerated acetic acid salt spray test (CASS): conducted according to Appendix C of GB / T 10125-2021; result evaluation: appearance evaluation according to GB / T1766-2008 "Rating method for aging of paint and varnish coatings"; Abrasion resistance: SY / T 0442-2020; Porosity grade: SY / T 0315-2013; Drag reduction rate: There is no applicable national / industry standard; a custom test method is used (DN50 pipe, 150℃ water, 1.0m / s flow velocity, pressure difference method for determination).

[0071] Figure 1 The image shows the water contact angle of the high-temperature, high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating prepared in Example 1 after curing. The contact angle of the coating surface (0 μm) is 104.34°.

[0072] The high-temperature, high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating of Example 1 was subjected to layer-by-layer grinding tests after curing. After grinding 50 μm, the contact angle decreased to 94°, and after grinding 100 μm, it stabilized at 91°~82°, proving that polytetrafluoroethylene micropowder formed a 50 μm enriched layer on the coating surface; the surface energy of this enriched layer (32.5 mJ / m²) was... 2 The surface enrichment drag reduction logic is confirmed because the surface is significantly lower than the interior.

[0073] The wear resistance of the cured high-temperature, high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating from Example 1 was verified: according to SY / T 0442-2020, the abrasion loss was ≤0.08 g / cm³. 2 After wear resistance, the contact angle is 94.51°. Figure 2 ), with long-lasting and stable hydrophobic and drag-reducing properties.

[0074] The coating performance test results of the coatings prepared in Examples 1-3 and Comparative Examples 1-5 after curing are shown in Table 1.

[0075] Table 1. Test results of coating performance after curing of the coatings prepared in Examples 1-3 and Comparative Examples 1-5.

[0076] In Comparative Example 1, the lack of polytetrafluoroethylene (PTFE) micropowder resulted in a significant decrease in the drag reduction rate (%) of the coating. In Comparative Example 2, increasing the proportion of PTFE micropowder led to an increase in the porosity of the coating and a decrease in its corrosion resistance. This is because PTFE undergoes self-agglomeration, forming numerous tiny voids and weak interfaces within the coating, thus failing to achieve a long-term anti-corrosion effect. In Comparative Example 3, the coating raw materials did not contain inorganic composite fillers, making it impossible to achieve an ultra-low porosity, dense structure, and consequently, a long-term anti-corrosion effect. In Comparative Examples 4 and 5, adjusting the equivalent ratio of epoxy groups in the epoxy resin composition to phenolic hydroxyl groups in the phenolic resin curing agent—whether too small or too large—both resulted in an increase in the porosity of the coating and a decrease in its corrosion resistance.

[0077] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-temperature, high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating, characterized in that, Its raw materials, by weight, include: The composition comprises 100-400 parts of epoxy resin, 50-200 parts of phenolic resin curing agent, 0.2-1.5 parts of curing accelerator, 5-40 parts of polytetrafluoroethylene micro powder, 200-600 parts of inorganic composite filler, and 5-50 parts of composite additives. The epoxy resin composition includes phenolic epoxy resin and bisphenol A epoxy resin. Inorganic composite packings include inorganic needle-shaped packings and inorganic spherical packings; Composite additives include leveling agents, degassing agents, defoamers, and adhesion promoters.

2. The high-temperature, high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating as described in claim 1, characterized in that, In the epoxy resin composition, the epoxy equivalent is 200~900 g / eq; Preferably, in the epoxy resin composition, the epoxy equivalent of the phenolic epoxy resin is 200~230 g / eq, and the epoxy equivalent of the bisphenol A epoxy resin is 800~900 g / eq; the mass ratio of the phenolic epoxy resin to the bisphenol A epoxy resin is (1~3):1, preferably (2~2.5):

1.

3. The high-temperature, high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating as described in claim 1, characterized in that, In the epoxy resin composition, the phenolic epoxy resin includes one or more of o-cresol epoxy resin, phenolic epoxy resin, or bisphenol A epoxy resin.

4. The high-temperature, high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating as described in claim 1, characterized in that, The phenolic resin curing agent is one of linear phenolic resin, bisphenol A phenolic resin, or phenol-aralkyl phenolic resin; Alternatively, the hydroxyl equivalent of the phenolic resin curing agent is 100~120 g / eq.

5. The high-temperature, high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating as described in claim 1, characterized in that, The equivalent ratio of epoxy groups in the epoxy resin composition to phenolic hydroxyl groups in the phenolic resin curing agent is (0.95~1.05):

1.

6. The high-temperature, high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating as described in claim 1, characterized in that, Curing accelerators include one or more of 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole or benzyltriethylammonium chloride; Alternatively, the particle size of polytetrafluoroethylene micro powder is 1~15 μm.

7. The high-temperature, high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating as described in claim 1, characterized in that, In the inorganic composite filler, the inorganic needle-shaped filler includes one or more of wollastonite, sepiolite, acicular mica or potassium titanate whiskers; preferably, the particle size of the inorganic needle-shaped filler is 0.5~20 μm and the aspect ratio is (8~25):

1. Alternatively, in the inorganic composite filler, the inorganic spherical filler includes one or more of high-purity fused silica micro powder, spherical quartz powder, spherical alumina, or fumed silica; preferably, the particle size of the inorganic spherical filler is 0.5~15 μm; Alternatively, in inorganic composite packing, the mass ratio of inorganic spherical packing to inorganic needle packing is (2~5):

1.

8. The high-temperature, high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating as described in claim 1, characterized in that, In the composite additives, the mass ratio of leveling agent, degassing agent, defoamer and adhesion promoter is (3~7):(2~4):(2~4):(3~7); Alternatively, in the composite additives, the leveling agent includes an acrylate leveling agent; Alternatively, in the composite additives, the degassing agent includes benzoin; Alternatively, in the composite additives, the defoamer includes polysiloxane defoamers; Alternatively, in the composite additive, the adhesion promoter is a silane coupling agent; more preferably, the silane coupling agent is selected from one or more of γ-glycidoxypropyltrimethoxysilane (KH-560), γ-aminopropyltriethoxysilane (KH-550) or γ-methacryloyloxypropyltrimethoxysilane (KH-570).

9. The high-temperature, high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating as described in claim 1, characterized in that, The high-temperature and high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating also includes a colorant; Preferably, the colorant is composed of titanium dioxide and conductive carbon black.

10. The method for preparing the high-temperature, high-pressure drag-reducing, energy-saving, heavy-duty anti-corrosion coating according to any one of claims 1 to 9, characterized in that, Includes the following steps: Weigh the raw materials according to the weight ratio, pour them into the premix container and mix well; The mixed raw materials are added to a twin-screw extruder for melt extrusion. The extrusion screw speed frequency of the extruder is 40~60Hz, and the melt temperature of the extruder is controlled at 90~110℃. The extruded material is cooled by the pressure rollers, pressed into sheets, ground, and sieved to obtain a high-temperature, high-pressure, drag-reducing, energy-saving, heavy-duty anti-corrosion coating.

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