Pipe anticorrosive coating and method for producing the same

Abstract

The application provides a pipeline anticorrosive coating and a preparation method thereof, and relates to the technical field of material science and engineering. The pipeline anticorrosive coating is composed of glycidyl methacrylate (GMA) grafted polytetrafluoroethylene (PTFE) powder, phenolic epoxy resin and an epoxy resin curing agent. The GMA grafted PTFE powder is first activated and then grafted with GMA, and azobisisobutyronitrile (AIBN) is used to remove residual free radicals. The phenolic epoxy resin is composed of phenolic epoxy resin, polyethylene glycol diglycidyl ether, GMA grafted PTFE powder, silica powder, a solvent and an additive. The epoxy resin curing agent is composed of polyamide, DMP-30 and a solvent. The application can provide the pipeline anticorrosive coating with excellent corrosion resistance, temperature resistance and low frictional resistance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of material science and engineering, in particular to a pipeline anticorrosive coating and a preparation method thereof. BACKGROUND

[0002] The downhole pipeline of oil and gas exploitation bears important functions such as transmitting oil and gas, guiding fluid flow and protecting wellbore, and is a key channel connecting the underground oil and gas reservoir and the ground gathering system.

[0003] Due to the long-term transportation of various media by the pipeline deep underground, direct contact with high-temperature, high-pressure, high-salinity formation water and corrosive media containing H2S / CO2, the corrosion problem is particularly prominent. The performance of the pipeline body is degraded due to corrosion, and there are risks such as pipeline leakage and rupture in operation, which not only leads to huge economic losses due to frequent replacement of the pipe column, but also may cause well control safety risks and environmental pollution.

[0004] At present, for the protection of the downhole pipeline of oil and gas, anticorrosive coating is the most economical, simple and convenient method, however, the traditional pipeline anticorrosive coating has problems such as insufficient environmental adaptability, poor scratch resistance of the coating and insufficient high-temperature corrosion resistance.

[0005] It should be noted that the information disclosed in the above background section is only used to strengthen the understanding of the background of the present application, and therefore can include information that does not constitute prior art known to those of ordinary skill in the art. SUMMARY

[0006] The purpose of the present application is to provide a pipeline anticorrosive coating and a preparation method thereof, thereby at least partially overcoming the problem of insufficient performance of the pipeline anticorrosive coating.

[0007] According to a first aspect of this application, a method for preparing a pipeline anti-corrosion coating is provided, comprising: mixing tert-butyllithium (t-BuLi) with hexamethylphosphoric triamine (HMPA) under a nitrogen atmosphere to obtain a first mixture; adding polytetrafluoroethylene (PTFE) powder to the first mixture to obtain activated PTFE powder; mixing glycidyl methacrylate (GMA) with ethylene glycol butyl ether (BCS) to obtain a second mixture; adding activated PTFE powder to the second mixture to obtain a third mixture; and adding an initiator solution to the third mixture to obtain a fourth mixture. Impurities in the fourth mixture are removed to obtain GMA-grafted PTFE powder; wherein the initiator solution consists of azobisisobutyronitrile (AIBN) and BCS; the GMA-grafted PTFE powder, phenolic epoxy resin, polyethylene glycol diglycidyl ether, and xylene are mixed to obtain a fifth mixture; at least an antifoaming agent and a leveling agent are added to the fifth mixture to obtain a phenolic epoxy resin component; polyamide, xylene, and DMP-30 are mixed to obtain an epoxy resin curing agent component; the phenolic epoxy resin component and the epoxy resin curing agent component are mixed to obtain a pipeline anti-corrosion coating.

[0008] Optionally, glycidyl methacrylate (GMA) and ethylene glycol butyl ether (BCS) are mixed to obtain a second mixture, comprising: placing 0.5 to 2 parts by weight of glycidyl methacrylate (GMA) and 40 parts by weight of ethylene glycol butyl ether (BCS) in a three-necked flask equipped with an electric stirrer and a thermometer, and stirring at room temperature for 0.5 h to obtain the second mixture.

[0009] Optionally, activated PTFE powder is added to the second mixture to obtain a third mixture, comprising: adding 1 part of activated PTFE powder to the second mixture and reacting the mixture in a three-necked flask in a water bath at 70°C for 2 hours to obtain the third mixture.

[0010] Optionally, the initiator solution consists of 0.5 parts by weight of azobisisobutyronitrile (AIBN) and 10 parts by weight of BCS.

[0011] Optionally, an initiator solution is added to the third mixture to obtain a fourth mixture, comprising: adding an initiator solution to the third mixture and reacting at 70°C for 1 hour to obtain the fourth mixture.

[0012] Optionally, removing impurities from the fourth mixture to obtain GMA-grafted PTFE powder includes: washing the fourth mixture with anhydrous ethanol and acetone respectively to remove impurities; and drying the mixture after removing impurities to obtain GMA-grafted PTFE powder.

[0013] Optionally, GMA-grafted PTFE powder, phenolic epoxy resin, polyethylene glycol diglycidyl ether, and xylene are mixed to obtain a fifth mixture, comprising: placing 5-10 parts by weight of GMA-grafted PTFE powder, 50 parts by weight of phenolic epoxy resin, 9 parts by weight of polyethylene glycol diglycidyl ether, and 30 parts by weight of xylene in a beaker and dispersing it using a disperser for 1 hour to obtain the fifth mixture.

[0014] Optionally, at least a defoamer and a leveling agent are added to the fifth mixture to obtain a phenolic epoxy resin component, including: adding 0-5 parts of silica powder to the fifth mixture and stirring for 1 hour to obtain a sixth mixture; adding 0.5 parts of defoamer and 0.5 parts of leveling agent to the sixth mixture and stirring for 30 minutes to obtain a phenolic epoxy resin component.

[0015] Optionally, polyamide, xylene, and DMP-30 are mixed to obtain an epoxy resin curing agent component, comprising: placing 45 parts by weight of polyamide, 23 parts by weight of xylene, and 2 parts by weight of DMP-30 in a beaker and stirring to obtain the epoxy resin curing agent component.

[0016] According to a second aspect of this application, a pipeline anti-corrosion coating is provided, which is prepared using any of the above-described pipeline anti-corrosion coating preparation methods.

[0017] In the exemplary embodiments of this application, a phenolic epoxy anti-corrosion coating system based on glycidyl methacrylate (GMA) grafted with PTFE is used. After activating the PTFE surface with tert-butyllithium (t-BuLi) and hexamethylphosphoric triamine (HMPA), GMA is grafted onto it. Azobisisobutyronitrile (AIBN) is then used to remove residual free radicals from the system, efficiently introducing active epoxy groups onto the PTFE molecular chain while preventing PTFE self-aggregation. Furthermore, the modified PTFE is fully dispersed and compounded with the phenolic epoxy resin system. The epoxy groups in the GMA molecules improve the compatibility and dispersibility with the epoxy resin and increase the degree of crosslinking, achieving uniform and stable dispersion of PTFE particles in the coating. This results in a downhole pipeline-specific coating with low frictional resistance, excellent temperature resistance, and anti-corrosion properties.

[0018] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0019] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0020] Figure 1 A flowchart illustrating the preparation method of the pipeline anti-corrosion coating according to an embodiment of this application is shown.

[0021] Figure 2 The reaction formula for activating PTFE grafting in Example 3 of this application is shown.

[0022] Figure 3 The image shown is an SEM (Scanning Electron Microscope) image of the GMA-grafted PTFE powder in Example 3 of this application.

[0023] Figure 4 A planar SEM image of the anti-corrosion coating for pipes prepared according to Example 3 of this application is shown.

[0024] Figure 5 The friction coefficient test diagram of the anti-corrosion coating for pipelines prepared in Example 3 of this application is shown.

[0025] Figure 6 The Bode impedance diagram of the pipeline anti-corrosion coating prepared in Example 3 of this application is shown.

[0026] Figure 7 The Bode phase diagram of the anti-corrosion coating for pipelines prepared in Example 3 of this application is shown.

[0027] Figure 8 Optical photographs before and after showing the resistance to boiling water corrosion of the anti-corrosion coating of the pipeline prepared in Example 3 of this application are shown. Detailed Implementation

[0028] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make this application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art. The described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a full understanding of the embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced with one or more of the specific details omitted, or other methods, processes, steps, etc., can be employed. In other instances, well-known technical solutions are not shown or described in detail to avoid obscuring various aspects of this application.

[0029] Furthermore, the accompanying drawings are merely illustrative of this application and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore, repeated descriptions of them will be omitted. The flowcharts shown in the drawings are merely exemplary and do not necessarily include all steps. For example, some steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the actual situation. Additionally, all terms such as "first," "second," "third," "fourth," "fifth," and "sixth" below are for distinguishing purposes only and should not be construed as limiting the content of this application.

[0030] To address the issues of insufficient environmental adaptability, poor scratch resistance, and inadequate high-temperature corrosion resistance in pipeline anti-corrosion coatings, a special coating for downhole pipelines is provided, which combines friction reduction, high-temperature resistance, and long-term anti-corrosion properties. It can effectively resist the synergistic erosion of high-temperature mineralized water and sand-containing fluids, and has significant engineering application value for ensuring the safe and efficient exploitation of oil and gas fields and reducing resource waste and environmental pollution.

[0031] Based on this, this application provides a low-friction, high-temperature resistant pipeline anti-corrosion coating and its preparation method. This pipeline anti-corrosion coating uses phenolic epoxy resin with excellent corrosion resistance and temperature resistance as a base, combining it with PTFE filler, which has an ultra-low coefficient of friction, high heat resistance, and strong amphiphilicity, to address the low-friction, high-temperature resistant, and anti-corrosion requirements for media transmission within pipelines. To address the issue of PTFE's tendency to agglomerate in the resin, GMA grafting is used to introduce epoxy groups onto its surface, significantly improving its compatibility and dispersibility with the epoxy resin. Furthermore, the grafted PTFE can participate in the curing reaction, increasing the degree of crosslinking. To prevent PTFE from agglomerating during GMA grafting, residual free radicals are removed after GMA grafting, effectively inhibiting PTFE accumulation during the grafting process. The resin component is prepared by fully dispersing the modified PTFE and phenolic epoxy resin system, and then mixed with the epoxy resin curing agent component to achieve rapid curing and molding.

[0032] The pipeline anti-corrosion coating of this application is composed of polytetrafluoroethylene (PTFE) powder grafted with glycidyl methacrylate (GMA), phenolic epoxy resin, and epoxy resin curing agent.

[0033] The GMA-grafted PTFE powder is first activated and then grafted with GMA, and residual free radicals are removed using azobisisobutyronitrile (AIBN).

[0034] Phenolic epoxy resin is composed of phenolic epoxy resin, polyethylene glycol diglycidyl ether, GMA-grafted PTFE powder, silica powder, solvent and additives.

[0035] Epoxy resin curing agents consist of polyamide (e.g., polyamide 650), DMP-30, and solvents.

[0036] Figure 1 A flowchart illustrating a method for preparing a pipeline anti-corrosion coating according to an embodiment of this application is shown schematically. (Reference) Figure 1 The method for preparing the pipeline anti-corrosion coating according to the embodiments of this application may include the following steps:

[0037] S102. Under a nitrogen atmosphere, tert-butyllithium (t-BuLi) is mixed with hexamethylphosphoric triamine (HMPA) to obtain a first mixture, and polytetrafluoroethylene (PTFE) powder is added to the first mixture to obtain activated PTFE powder.

[0038] S104. Glycidyl methacrylate (GMA) is mixed with ethylene glycol butyl ether (BCS) to obtain a second mixture.

[0039] According to some embodiments of this application, 0.5 to 2 parts by weight of glycidyl methacrylate (GMA) and 40 parts by weight of ethylene glycol butyl ether (BCS) are placed in a three-necked flask equipped with an electric stirrer and a thermometer and stirred at room temperature for 0.5 hours to obtain a second mixture.

[0040] S106. Add activated PTFE powder to the second mixture to obtain a third mixture.

[0041] According to some embodiments of this application, one part of activated PTFE powder is added to the second mixture, and the three-necked flask is placed in a water bath at 70°C for 2 hours to obtain the third mixture.

[0042] S108. Add an initiator solution to the third mixture to obtain a fourth mixture, remove impurities from the fourth mixture to obtain GMA-grafted PTFE powder.

[0043] In an exemplary embodiment of this application, the initiator solution is composed of azobisisobutyronitrile (AIBN) and BCS. Specifically, by weight, the initiator solution may consist of 0.5 parts of AIBN and 10 parts of BCS.

[0044] To obtain the fourth mixture, an initiator solution can be added to the third mixture, and the mixture can be reacted at 70°C for 1 hour to obtain the fourth mixture.

[0045] To remove impurities, the fourth mixture can be washed with anhydrous ethanol and acetone respectively.

[0046] After removing impurities, the material is dried to obtain GMA-grafted PTFE powder.

[0047] S110. GMA-grafted PTFE powder, phenolic epoxy resin, polyethylene glycol diglycidyl ether, and xylene are mixed to obtain a fifth mixture.

[0048] According to some embodiments of this application, by weight, 5-10 parts of GMA-grafted PTFE powder, 50 parts of phenolic epoxy resin, 9 parts of polyethylene glycol diglycidyl ether and 30 parts of xylene can be placed in a beaker and dispersed using a disperser for 1 hour to obtain a fifth mixture.

[0049] S112. Add at least a defoamer and a leveling agent to the fifth mixture to obtain the phenolic epoxy resin component.

[0050] According to some embodiments of this application, firstly, 0-5 parts of silica powder can be added to the fifth mixture, and the mixture can be stirred and reacted for 1 hour to obtain the sixth mixture. Next, 0.5 parts of defoamer and 0.5 parts of leveling agent can be added to the sixth mixture, and the mixture can be stirred and reacted for 30 minutes to obtain the phenolic epoxy resin component.

[0051] S114. Mix polyamide, xylene and DMP-30 to obtain an epoxy resin curing agent component.

[0052] According to some embodiments of this application, by weight, 45 parts of polyamide, 23 parts of xylene and 2 parts of DMP-30 can be placed in a beaker and stirred to obtain the epoxy resin curing agent component.

[0053] S116. Mix the phenolic epoxy resin component with the epoxy resin curing agent component to obtain a pipeline anti-corrosion coating.

[0054] According to some embodiments of this application, by weight, 100 parts of phenolic epoxy resin component can be placed in a beaker, and then 70 parts of epoxy resin curing agent component can be added. The mixture is stirred and reacted for 5 minutes to obtain the low-friction and high-temperature resistant pipe anti-corrosion coating of this application.

[0055] Furthermore, this application also provides a pipeline anti-corrosion coating, which is prepared using the preparation method described in steps S102 to S116 above.

[0056] In the exemplary embodiments of this application, the anti-corrosion coating is composed of GMA-grafted PTFE powder, phenolic epoxy resin, and epoxy resin curing agent. Since the chain termination process during GMA grafting leads to PTFE self-aggregation, residual free radicals are removed after GMA grafting to suppress PTFE accumulation during the grafting process. Simultaneously, the GMA-grafted PTFE powder serves as a core functional filler, improving compatibility and dispersibility with the epoxy resin through surface epoxy groups and participating in the curing reaction to enhance crosslinking. Phenolic epoxy resin is used as a high-temperature resistant anti-corrosion matrix, synergistically with the ultra-low friction coefficient, high heat resistance, and strong amphiphilicity of PTFE to construct a coating system possessing low friction resistance, excellent temperature resistance, and anti-corrosion performance. After activation, the surface F element of PTFE is replaced by highly active free radicals, which then initiate GMA grafting polymerization. The addition of AIBN completes chain termination, thereby achieving successful grafting of GMA onto the PTFE surface while preventing PTFE self-aggregation.

[0057] The preparation method of the pipeline anti-corrosion coating of Example 1 of this application will be described below.

[0058] Regarding the process of preparing GMA-grafted PTFE powder:

[0059] First, under a nitrogen atmosphere, tert-butyllithium (t-BuLi) and hexamethylphosphoric triamine (HMPA) were uniformly mixed, and polytetrafluoroethylene (PTFE) powder was added to obtain activated PTFE powder. Next, 0.5 g of glycidyl methacrylate (GMA) and 40 g of ethylene glycol butyl ether (BCS) were mixed and poured into a three-necked flask equipped with an electric stirrer and a thermometer. After stirring at room temperature for 0.5 h, 1 g of activated PTFE powder was added, and the mixture was placed in a 70 °C water bath for 2 h. Subsequently, an initiator solution consisting of 0.5 g of azobisisobutyronitrile (AIBN) and 10 g of BCS was added, and the system was kept at 70 °C for 1 h. After the reaction was completed, the product was washed with anhydrous ethanol and acetone to remove impurities, and dried to obtain white GMA-grafted PTFE powder.

[0060] Regarding the process of preparing phenolic epoxy resin components and epoxy resin curing agent components:

[0061] First, 50g of phenolic epoxy resin, 9g of polyethylene glycol diglycidyl ether, 30g of xylene, and 7g of GMA-grafted PTFE powder were weighed into a beaker and dispersed at 1500 rpm for 1 hour using a high-speed disperser. Then, 3g of silica powder was added to the beaker, and the mixture was stirred for 1 hour. Next, 0.5g of defoamer and 0.5g of leveling agent were added, and the mixture was stirred for 30 minutes to obtain the phenolic epoxy resin component. Separately, 45g of polyamide 650, 23g of xylene, and 2g of DMP-30 were weighed into a beaker and mixed evenly using magnetic stirring to obtain the epoxy resin curing agent component.

[0062] Regarding the process of preparing pipeline anti-corrosion coatings:

[0063] Take 100g of the mixed phenolic epoxy resin component and place it in a beaker. Add 70g of epoxy resin curing agent component and stir for 5 minutes to obtain the pipeline anti-corrosion coating prepared in Example 1.

[0064] The preparation method of the pipeline anti-corrosion coating of Example 2 of this application will be described below.

[0065] Regarding the process of preparing GMA-grafted PTFE powder:

[0066] First, under a nitrogen atmosphere, tert-butyllithium (t-BuLi) and hexamethylphosphoric triamine (HMPA) were uniformly mixed, and polytetrafluoroethylene (PTFE) powder was added to obtain activated PTFE powder. Next, 1 g of glycidyl methacrylate (GMA) and 40 g of ethylene glycol butyl ether (BCS) were mixed and poured into a three-necked flask equipped with an electric stirrer and a thermometer. After stirring at room temperature for 0.5 h, 1 g of activated PTFE powder was added, and the mixture was placed in a 70 °C water bath for 2 h. Subsequently, an initiator solution consisting of 0.5 g of azobisisobutyronitrile (AIBN) and 10 g of BCS was added, and the system was kept at 70 °C for 1 h. After the reaction was completed, the product was washed with anhydrous ethanol and acetone to remove impurities, and dried to obtain white GMA-grafted PTFE powder.

[0067] Regarding the process of preparing phenolic epoxy resin components and epoxy resin curing agent components:

[0068] First, 50g of phenolic epoxy resin, 9g of polyethylene glycol diglycidyl ether, 30g of xylene, and 7g of GMA-grafted PTFE powder were weighed into a beaker and dispersed at 1500 rpm for 1 hour using a high-speed disperser. Then, 3g of silica powder was added to the beaker, and the mixture was stirred for 1 hour. Next, 0.5g of defoamer and 0.5g of leveling agent were added, and the mixture was stirred for 30 minutes to obtain the phenolic epoxy resin component. Separately, 45g of polyamide 650, 23g of xylene, and 2g of DMP-30 were weighed into a beaker and mixed evenly using magnetic stirring to obtain the epoxy resin curing agent component.

[0069] Regarding the process of preparing pipeline anti-corrosion coatings:

[0070] Take 100g of the mixed phenolic epoxy resin component and place it in a beaker. Add 70g of epoxy resin curing agent component and stir for 5 minutes to obtain the pipeline anti-corrosion coating prepared in Example 2.

[0071] The preparation method of the pipeline anti-corrosion coating of Example 3 of this application will be described below.

[0072] Regarding the process of preparing GMA-grafted PTFE powder:

[0073] First, under a nitrogen atmosphere, tert-butyllithium (t-BuLi) and hexamethylphosphoric triamine (HMPA) were uniformly mixed, and polytetrafluoroethylene (PTFE) powder was added to obtain activated PTFE powder. Next, 1.5 g of glycidyl methacrylate (GMA) and 40 g of ethylene glycol butyl ether (BCS) were mixed and poured into a three-necked flask equipped with an electric stirrer and a thermometer. After stirring at room temperature for 0.5 h, 1 g of activated PTFE powder was added, and the mixture was placed in a 70 °C water bath for 2 h. Subsequently, an initiator solution consisting of 0.5 g of azobisisobutyronitrile (AIBN) and 10 g of BCS was added, and the system was kept at 70 °C for 1 h. After the reaction was completed, the product was washed with anhydrous ethanol and acetone to remove impurities, and dried to obtain white GMA-grafted PTFE powder.

[0074] Figure 2 The reaction formula for activating PTFE grafting in Example 3 of this application is shown.

[0075] Regarding the process of preparing phenolic epoxy resin components and epoxy resin curing agent components:

[0076] First, 50g of phenolic epoxy resin, 9g of polyethylene glycol diglycidyl ether, 30g of xylene, and 7g of GMA-grafted PTFE powder were weighed into a beaker and dispersed at 1500 rpm for 1 hour using a high-speed disperser. Then, 3g of silica powder was added to the beaker, and the mixture was stirred for 1 hour. Next, 0.5g of defoamer and 0.5g of leveling agent were added, and the mixture was stirred for 30 minutes to obtain the phenolic epoxy resin component. Separately, 45g of polyamide 650, 23g of xylene, and 2g of DMP-30 were weighed into a beaker and mixed evenly using magnetic stirring to obtain the epoxy resin curing agent component.

[0077] Regarding the process of preparing pipeline anti-corrosion coatings:

[0078] Take 100g of the mixed phenolic epoxy resin component and place it in a beaker. Add 70g of epoxy resin curing agent component and stir for 5 minutes to obtain the pipeline anti-corrosion coating prepared in Example 3.

[0079] The preparation method of the pipeline anti-corrosion coating of Example 4 of this application will be described below.

[0080] Regarding the process of preparing GMA-grafted PTFE powder:

[0081] First, under a nitrogen atmosphere, tert-butyllithium (t-BuLi) and hexamethylphosphoric triamine (HMPA) were uniformly mixed, and polytetrafluoroethylene (PTFE) powder was added to obtain activated PTFE powder. Next, 2g of glycidyl methacrylate (GMA) and 40g of ethylene glycol butyl ether (BCS) were mixed and poured into a three-necked flask equipped with an electric stirrer and a thermometer. After stirring at room temperature for 0.5h, 1g of activated PTFE powder was added, and the mixture was placed in a 70°C water bath for 2h. Subsequently, an initiator solution consisting of 0.5g of azobisisobutyronitrile (AIBN) and 10g of BCS was added, and the system was kept at 70°C for 1h. After the reaction was completed, the product was washed with anhydrous ethanol and acetone to remove impurities, and dried to obtain white GMA-grafted PTFE powder.

[0082] Regarding the process of preparing phenolic epoxy resin components and epoxy resin curing agent components:

[0083] First, 50g of phenolic epoxy resin, 9g of polyethylene glycol diglycidyl ether, 30g of xylene, and 7g of GMA-grafted PTFE powder were weighed into a beaker and dispersed at 1500 rpm for 1 hour using a high-speed disperser. Then, 3g of silica powder was added to the beaker, and the mixture was stirred for 1 hour. Next, 0.5g of defoamer and 0.5g of leveling agent were added, and the mixture was stirred for 30 minutes to obtain the phenolic epoxy resin component. Separately, 45g of polyamide 650, 23g of xylene, and 2g of DMP-30 were weighed into a beaker and mixed evenly using magnetic stirring to obtain the epoxy resin curing agent component.

[0084] Regarding the process of preparing pipeline anti-corrosion coatings:

[0085] Take 100g of the mixed phenolic epoxy resin component and place it in a beaker. Add 70g of epoxy resin curing agent component and stir for 5 minutes to obtain the pipeline anti-corrosion coating prepared in Example 4.

[0086] The preparation method of the pipeline anti-corrosion coating of Example 5 of this application will be described below.

[0087] Regarding the process of preparing GMA-grafted PTFE powder:

[0088] First, under a nitrogen atmosphere, tert-butyllithium (t-BuLi) and hexamethylphosphoric triamine (HMPA) were uniformly mixed, and polytetrafluoroethylene (PTFE) powder was added to obtain activated PTFE powder. Next, 1.5 g of glycidyl methacrylate (GMA) and 40 g of ethylene glycol butyl ether (BCS) were mixed and poured into a three-necked flask equipped with an electric stirrer and a thermometer. After stirring at room temperature for 0.5 h, 1 g of activated PTFE powder was added, and the mixture was placed in a 70 °C water bath for 2 h. Subsequently, an initiator solution consisting of 0.5 g of azobisisobutyronitrile (AIBN) and 10 g of BCS was added, and the system was kept at 70 °C for 1 h. After the reaction was completed, the product was washed with anhydrous ethanol and acetone to remove impurities, and dried to obtain white GMA-grafted PTFE powder.

[0089] Regarding the process of preparing phenolic epoxy resin components and epoxy resin curing agent components:

[0090] First, 50g of phenolic epoxy resin, 9g of polyethylene glycol diglycidyl ether, 30g of xylene, and 10g of GMA-grafted PTFE powder were weighed into a beaker and dispersed at 1500 rpm for 1 hour using a high-speed disperser. Then, 3g of silica powder was added to the beaker, and the mixture was stirred for 1 hour. Next, 0.5g of defoamer and 0.5g of leveling agent were added, and the mixture was stirred for 30 minutes to obtain the phenolic epoxy resin component. Separately, 45g of polyamide 650, 23g of xylene, and 2g of DMP-30 were weighed into a beaker and mixed evenly using magnetic stirring to obtain the epoxy resin curing agent component.

[0091] Regarding the process of preparing pipeline anti-corrosion coatings:

[0092] Take 100g of the mixed phenolic epoxy resin component and place it in a beaker. Add 70g of epoxy resin curing agent component and stir for 5 minutes to obtain the pipeline anti-corrosion coating prepared in Example 5.

[0093] The preparation method of Comparative Example 1 is described below.

[0094] 50g of phenolic epoxy resin, 9g of polyethylene glycol diglycidyl ether, 30g of xylene, and 7g of unmodified PTFE powder were weighed into a beaker and dispersed at 1500 rpm for 1 hour using a high-speed disperser. Then, 3g of silica powder was added to the beaker, and the mixture was stirred for 1 hour. Next, 0.5g of defoamer and 0.5g of leveling agent were added, and the mixture was stirred for 30 minutes to obtain the epoxy resin component. 45g of polyamide 650, 23g of xylene, and 2g of DMP-30 were weighed into a beaker and mixed evenly using magnetic stirring to obtain the epoxy resin curing agent component.

[0095] Take 100g of the mixed phenolic epoxy resin component and place it in a beaker. Add 70g of epoxy resin curing agent component and stir for 5 minutes to obtain the pipeline anti-corrosion coating prepared in Comparative Example 1.

[0096] The preparation method of Comparative Example 2 is described below.

[0097] Under a nitrogen atmosphere, tert-butyllithium (t-BuLi) and hexamethylphosphoric triamine (HMPA) were uniformly mixed, and polytetrafluoroethylene (PTFE) powder was added to obtain activated PTFE powder. 1 g of PTFE was added to 10 g of a 20% (volume fraction) glycidyl methacrylate (GMA) ethanol solution, and the mixture was reacted at 70 °C for 8 h. After the reaction, the product was washed in deionized water at 50 °C for 3 h. Impurities were then washed with anhydrous ethanol and acetone at room temperature using the same method. After drying, a white GMA-grafted PTFE powder was obtained.

[0098] 50g of phenolic epoxy resin, 9g of polyethylene glycol diglycidyl ether, 30g of xylene, and 7g of GMA-grafted PTFE powder were weighed into a beaker and dispersed at 1500 rpm for 1 hour using a high-speed disperser. Then, 3g of silica powder was added to the beaker, and the mixture was stirred for 1 hour. Next, 0.5g of defoamer and 0.5g of leveling agent were added, and the mixture was stirred for 30 minutes to obtain the phenolic epoxy resin component. Separately, 45g of polyamide 650, 23g of xylene, and 2g of DMP-30 were weighed into a beaker and mixed evenly using magnetic stirring to obtain the epoxy resin curing agent component.

[0099] Take 100g of the mixed phenolic epoxy resin component and place it in a beaker. Add 70g of epoxy resin curing agent component and stir for 5 minutes to obtain the pipeline anti-corrosion coating prepared in Comparative Example 2.

[0100] The GMA-grafted PTFE powders obtained in Examples 1-5 and Comparative Examples 1 and 2 were dispersed in ethanol, and the dispersions were coated onto single-crystal silicon wafers and dried at room temperature. The dispersibility of the PTFE powders was observed using SEM.

[0101] Taking the SEM image of the GMA-grafted PTFE powder in Example 3 as an example, refer to... Figure 3 It can be seen that the improved PTFE powder particles have good dispersibility, indicating that the surface properties of PTFE are changed by the grafting process, and that removing residual free radicals is beneficial to improving dispersibility.

[0102] The coatings obtained in Examples 1-5 and Comparative Examples 1-2 were applied to the surface of bearing steel GCr15 using conventional spraying methods. Nozzles with diameters of 1.0-1.5 mm were selected, spraying pressures were set at 0.3-0.5 MPa, spraying distances were controlled at 20-30 cm, and coating thicknesses were controlled at 80-100 μm. Curing was carried out at room temperature. The microstructure of the coating surface was observed using SEM.

[0103] Taking the planar SEM image of the pipeline anti-corrosion coating in Example 3 as an example, refer to... Figure 4 The coating surface is relatively regular, with only a small amount of accumulation in local areas, indicating that GMA-modified PTFE effectively improves the agglomeration of PTFE powder.

[0104] The coefficient of friction of the coating was tested using the reciprocating module of a friction and wear tester. The load was set to 10 N, the time to 60 min, the test frequency to 0.5 Hz, and the length to 5 mm.

[0105] Taking the friction coefficient test results of the pipeline anti-corrosion coating in Example 3 as an example, refer to... Figure 5 The average coefficient of friction on the coating surface is approximately 0.078, resulting in low frictional resistance.

[0106] The electrochemical impedance and phase angle of the coating were tested using an electrochemical workstation with a 3.5% NaCl aqueous solution as the electrolyte and a test frequency of 10 Hz. -2 ~10 5 Hz, sinusoidal voltage of 20mV, soak the sample for 1h. Heat pure water and maintain it at 80±2℃ to completely immerse the coating in hot water. After boiling, remove and let stand at room temperature.

[0107] Taking Example 3 as an example, refer to Figure 6 and Figure 7 Electrochemical test results show that the coating has excellent anti-corrosion properties.

[0108] in addition, Figure 8 Optical photographs before and after boiling water corrosion resistance of the pipeline anti-corrosion coating prepared in Example 3 of this application are shown. (Reference) Figure 8 After 720 hours of boiling water corrosion resistance test, no obvious corrosion was found in the substrate, demonstrating long-lasting anti-corrosion performance.

[0109] Table 1 shows the experimental results of Examples 1-5 and Comparative Examples 1 and 2.

[0110] Table 1

[0111]

[0112] In summary, the pipeline anti-corrosion coating of this application significantly reduces the coefficient of friction of the coating, improves the upper limit of temperature resistance and long-term anti-corrosion performance, and solves the defects of traditional downhole anti-corrosion coatings such as insufficient heat resistance and accelerated failure due to sand-containing fluid erosion. It can meet the requirements of deep and ultra-deep well pipelines for integrated erosion resistance, high temperature resistance and long-term anti-corrosion under harsh working conditions.

[0113] It should be noted that although the steps of the method in this application are described in a specific order in the accompanying drawings, this does not require or imply that the steps must be performed in that specific order, or that all the steps shown must be performed to achieve the desired result. Additional or alternative steps may be omitted, multiple steps may be combined into one step, and / or one step may be broken down into multiple steps.

[0114] Furthermore, the above figures are merely illustrative of the processes included in the method according to exemplary embodiments of this application, and are not intended to be limiting. It is readily understood that the processes shown in the above figures do not indicate or limit the temporal order of these processes. Additionally, it is readily understood that these processes may be executed synchronously or asynchronously, for example, in multiple modules.

[0115] Other embodiments of this application will readily conceive of by those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only, and the true scope and spirit of this application are indicated by the claims.

[0116] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A method for preparing a pipeline anti-corrosion coating, characterized in that, include: Under a nitrogen atmosphere, tert-butyllithium (t-BuLi) was mixed with hexamethylphosphoric triamine (HMPA) to obtain a first mixture, and polytetrafluoroethylene (PTFE) powder was added to the first mixture to obtain activated PTFE powder. Glycidyl methacrylate (GMA) was mixed with ethylene glycol butyl ether (BCS) to obtain a second mixture; The activated PTFE powder is added to the second mixture to obtain a third mixture; An initiator solution is added to the third mixture to obtain a fourth mixture. Impurities in the fourth mixture are removed to obtain GMA-grafted PTFE powder. The initiator solution is composed of azobisisobutyronitrile (AIBN) and BCS. The GMA-grafted PTFE powder, phenolic epoxy resin, polyethylene glycol diglycidyl ether, and xylene are mixed to obtain a fifth mixture; At least a defoamer and a leveling agent are added to the fifth mixture to obtain a phenolic epoxy resin component; Polyamide, xylene, and DMP-30 are mixed to obtain an epoxy resin curing agent component; The phenolic epoxy resin component is mixed with the epoxy resin curing agent component to obtain a pipeline anti-corrosion coating.

2. The preparation method according to claim 1, characterized in that, Glycidyl methacrylate (GMA) was mixed with ethylene glycol butyl ether (BCS) to obtain a second mixture comprising: By weight, 0.5 to 2 parts of glycidyl methacrylate (GMA) and 40 parts of ethylene glycol butyl ether (BCS) were placed in a three-necked flask equipped with an electric stirrer and a thermometer and stirred at room temperature for 0.5 hours to obtain a second mixture.

3. The preparation method according to claim 2, characterized in that, The activated PTFE powder is added to the second mixture to obtain a third mixture, comprising: Add one part of the activated PTFE powder to the second mixture, and place the three-necked flask in a water bath at 70°C for 2 hours to obtain the third mixture.

4. The preparation method according to claim 1, characterized in that, The initiator solution consists of 0.5 parts by weight of azobisisobutyronitrile (AIBN) and 10 parts by weight of BCS.

5. The preparation method according to claim 4, characterized in that, An initiator solution is added to the third mixture to obtain a fourth mixture, comprising: An initiator solution was added to the third mixture, and the mixture was reacted at 70°C for 1 hour to obtain a fourth mixture.

6. The preparation method according to claim 5, characterized in that, To remove impurities from the fourth mixture to obtain GMA-grafted PTFE powder, comprising: The fourth mixture was washed with anhydrous ethanol and acetone respectively to remove impurities; After removing impurities, the material is dried to obtain GMA-grafted PTFE powder.

7. The preparation method according to claim 1, characterized in that, The GMA-grafted PTFE powder, phenolic epoxy resin, polyethylene glycol diglycidyl ether, and xylene are mixed to obtain a fifth mixture comprising: By weight, 5-10 parts of the GMA-grafted PTFE powder, 50 parts of phenolic epoxy resin, 9 parts of polyethylene glycol diglycidyl ether, and 30 parts of xylene are placed in a beaker and dispersed using a disperser for 1 hour to obtain the fifth mixture.

8. The preparation method according to claim 7, characterized in that, At least an antifoaming agent and a leveling agent are added to the fifth mixture to obtain a phenolic epoxy resin component, comprising: Add 0-5 parts of silica powder to the fifth mixture and stir for 1 hour to obtain the sixth mixture; Add 0.5 parts of defoamer and 0.5 parts of leveling agent to the sixth mixture, and stir for 30 minutes to obtain the phenolic epoxy resin component.

9. The preparation method according to claim 1, characterized in that, Polyamide, xylene, and DMP-30 are mixed to obtain an epoxy resin curing agent component, comprising: By weight, 45 parts polyamide, 23 parts xylene and 2 parts DMP-30 were placed in a beaker and stirred to obtain the epoxy resin curing agent components.

10. A pipeline anti-corrosion coating, characterized in that, The anti-corrosion coating for pipelines is prepared using the preparation method described in any one of claims 1 to 9.

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