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CN-121821842-B - High-temperature-resistant cathode stripping-resistant 3PE anti-corrosion pipeline and preparation method thereof

CN121821842BCN 121821842 BCN121821842 BCN 121821842BCN-121821842-B

Abstract

The invention belongs to the technical field of 3PE corrosion prevention, and particularly relates to a high-temperature-resistant cathode stripping-resistant 3PE corrosion-resistant pipeline and a preparation method thereof. The epoxy bottom layer is modified by phenolic resin and aminosilane to form a heat-resistant compact barrier, the middle layer is reacted with maleic anhydride grafted polyethylene to form a chemical bridge which is simultaneously connected with the upper layer and the lower layer, the surface layer is grafted with high-density polyethylene by primary fluoropamine modified glycidyl methacrylate, a hydrophobic oleophobic chain and a reactive functional group are introduced, and the structure improves the long-term use temperature upper limit, stripping resistance and medium permeation resistance of the pipeline by the synergistic effect of the high temperature stability of the bottom layer, the bidirectional chemical bridging capacity of the middle layer and the inert hydrophobic property of the surface layer.

Inventors

  • XU HUANPING
  • LI JINGRU
  • YAN YUXIANG
  • Ju Haiwei

Assignees

  • 潍坊中石科技有限公司

Dates

Publication Date
20260512
Application Date
20260312

Claims (6)

  1. 1. The preparation method of the high-temperature-resistant cathode stripping-resistant 3PE anti-corrosion pipeline is characterized by comprising the following steps of: S1, selecting a complete steel pipe without mechanical damage and oil pollution, performing shot blasting and rust removal on the inner side and the outer side of the steel pipe to enable the rust removal grade of the surface of the steel pipe to reach the Sa2.5 grade, blowing the surface by clean and dry air, preheating the steel pipe to 210-240 ℃ and keeping the temperature for 1-3 min; s2, uniformly spraying silane modified epoxy resin powder on the outer surface of the preheated steel pipe by adopting an electrostatic spraying process, so that the steel pipe is melted and leveled to reach a gel solidification state, and an epoxy bottom layer is formed; S3, when the temperature of the epoxy bottom layer is reduced to 100-150 ℃, using a co-extrusion winding device to melt and extrude silane modified maleic anhydride grafted polyethylene at 190-210 ℃ to serve as an intermediate layer; S4, continuously using co-extrusion winding equipment when the temperature of the middle layer is reduced to 150-180 ℃, and melting and extruding the fluorinated primary amine modified GMA grafted high-density polyethylene at 200-220 ℃ to serve as a surface layer, and winding and coating the surface of the middle layer to obtain a steel pipe with a three-layer composite structure; S5, carrying out further heat treatment on the steel pipe with the three-layer composite structure, wherein the temperature is 170-200 ℃, the time is 30-90S, and cooling to room temperature to obtain a high-temperature-resistant cathode stripping-resistant 3PE anti-corrosion pipeline; The preparation method of the silane modified epoxy resin powder comprises the steps of placing bisphenol A epoxy resin, a phenolic resin curing agent, an aminosilane coupling agent, pigment and filler and an auxiliary agent in a high-speed mixer, premixing for 10-20 min at 60-80 ℃ to obtain a premix, carrying out melt blending on the premix through a double-screw extruder, setting the temperature of the extruder to 120-140 ℃ and the screw rotating speed to 100-300 rpm, cooling and fracturing the extruded material, and crushing the extruded material through a micro-pulverizer to obtain the silane modified epoxy resin powder; The preparation method of the silane modified maleic anhydride grafted polyethylene comprises the steps of premixing maleic anhydride grafted polyethylene granules, an aminosilane coupling agent and an esterification catalyst in a stirrer to obtain a premix, carrying out reactive melt extrusion on the premix by a double-screw extruder, setting the temperature of the extruder to be 170-200 ℃ and the material residence time to be 1-3 min, cooling, and granulating by a granulator to obtain the silane modified maleic anhydride grafted polyethylene; The preparation method of the fluoroprimine modified GMA grafted high-density polyethylene comprises the steps of mixing high-density polyethylene granules, fluoroprimine modified glycidyl methacrylate, dicumyl peroxide and an antioxidant to obtain a mixed material, carrying out melt grafting reaction on the mixed material through a double-screw extruder under the protection of nitrogen, controlling the temperature of the extruder along the screw in a sectional manner, gradually increasing the temperature from 160-180 ℃ of a feeding section to 190-210 ℃ of a reaction section, and keeping the material for 2-5 min; The preparation method of the fluorine primary amine modified glycidyl methacrylate comprises the steps of mixing the glycidyl methacrylate with fluorine primary amine, stirring and reacting for 5-8 hours under the protection of nitrogen atmosphere at 65-75 ℃, cooling to room temperature after the reaction is completed to obtain a reaction liquid, dropwise adding the reaction liquid into normal hexane under stirring, filtering out a solid product, washing 2-3 times with fresh normal hexane, and vacuum drying at 40-50 ℃ to constant weight to obtain the fluorine primary amine modified glycidyl methacrylate.
  2. 2. The preparation method of the high-temperature-resistant cathode stripping-resistant 3PE anti-corrosion pipeline is characterized in that the mass ratio of bisphenol A epoxy resin to phenolic resin curing agent to aminosilane coupling agent is 100:20-35:1-5, and the aminosilane coupling agent is gamma-aminopropyl triethoxysilane or N-aminoethyl-gamma-aminopropyl trimethoxysilane.
  3. 3. The preparation method of the high-temperature-resistant cathode stripping-resistant 3PE anti-corrosion pipeline is characterized in that the mass ratio of maleic anhydride grafted polyethylene granules to an aminosilane coupling agent is 100:3-6, the grafting rate of the maleic anhydride grafted polyethylene granules is 0.8-1.5%, the aminosilane coupling agent is N-aminoethyl-gamma-aminopropyl trimethoxysilane, the esterification catalyst is dibutyltin dilaurate, and the addition amount of the catalyst is 0.1-0.3% of the mass of the maleic anhydride grafted polyethylene granules.
  4. 4. The preparation method of the high-temperature-resistant cathode stripping-resistant 3PE anti-corrosion pipeline is characterized in that the mass ratio of the high-density polyethylene granules to the fluoroprimine modified glycidyl methacrylate to the dicumyl peroxide is 100:1.5-4:0.1-0.3.
  5. 5. The preparation method of the high-temperature-resistant cathode stripping-resistant 3PE anti-corrosion pipeline is characterized in that the fluorine-containing primary amine is 1H, 1H-perfluoroheptyl amine or 1H, 1H-perfluorooctyl amine, the molar ratio of glycidyl methacrylate to the fluorine-containing primary amine is 1:0.8-1.2, and the volume of normal hexane is 5-10 times of the volume of a reaction solution.
  6. 6. The high-temperature-resistant cathode stripping-resistant 3PE anti-corrosion pipeline is characterized by being prepared by the preparation method of the high-temperature-resistant cathode stripping-resistant 3PE anti-corrosion pipeline according to any one of claims 1-5.

Description

High-temperature-resistant cathode stripping-resistant 3PE anti-corrosion pipeline and preparation method thereof Technical Field The invention belongs to the technical field of 3PE corrosion prevention, and particularly relates to a high-temperature-resistant cathode stripping-resistant 3PE corrosion-resistant pipeline and a preparation method thereof. Background Steel pipelines are key infrastructure for delivering oil and gas resources, and are long-term in complex soil, electrolyte and stress environments, corrosion and protection are core problems for determining the service life and operation safety of the pipelines. The technology of a three-layer structure polyethylene (3 PE) anti-corrosion layer is a preferred scheme for pipeline anti-corrosion. The standard 3PE anticorrosive layer is of a typical three-layer composite structure, wherein the bottom layer is a sintered epoxy powder coating, the surface of a preheated steel pipe is sintered through electrostatic spraying to form a continuous anticorrosive base layer with excellent insulativity and compatible with a cathode protection system, the middle layer is an adhesive layer, polymers such as maleic anhydride grafted polyethylene and the like are generally adopted to be covered on the epoxy powder coating through coextrusion winding, physical bonding and transition between a nonpolar polyethylene surface layer and a polar epoxy bottom layer are realized, and the surface layer is a high-density or medium-density polyethylene extrusion layer, so that main mechanical protection is provided, and soil stress, rock scratch and moisture permeation are resisted. Although the 3PE anticorrosion technology is mature, the performance of the 3PE anticorrosion technology still faces serious challenges under severe working conditions such as high temperature, complex corrosion and the like, firstly, the adhesive of the middle layer and the upper layer and the lower layer mainly depend on physical entanglement and polar adsorption of molecular chains, strong chemical bonding is lacking, interlayer peeling easily occurs under the long-term heat aging, soil stress or temperature difference circulation effect, so that a protection system is invalid, secondly, the long-term use temperature of a standard epoxy powder layer is usually not higher than 80 ℃, when the temperature of a conveying medium is higher or the conveying medium is in a heating pipeline application state, the adhesive force and the deformation resistance of the adhesive layer are rapidly reduced, meanwhile, the adhesive layer is softened, the interlayer bonding force is seriously attenuated, and besides, the permeation resistance of the epoxy bottom layer of the traditional 3PE structure to the corrosive medium is insufficient under the cathode protection environment with higher temperature. Therefore, developing a novel 3PE anti-corrosion pipeline capable of enhancing interlayer bonding, improving high temperature resistance and cathode stripping resistance has become a technical problem to be solved in the field. Disclosure of Invention The invention aims to provide a high-temperature-resistant cathode stripping-resistant 3PE anti-corrosion pipeline and a preparation method thereof, so as to solve the technical problems. In order to achieve the technical purpose, the technical scheme of the invention comprises the following steps: a preparation method of a high-temperature-resistant cathode stripping-resistant 3PE anti-corrosion pipeline comprises the following steps: S1, selecting a complete steel pipe without mechanical damage and oil pollution, performing shot blasting and rust removal on the inner side and the outer side of the steel pipe to enable the rust removal grade of the surface of the steel pipe to reach the Sa2.5 grade, blowing the surface by clean and dry air, preheating the steel pipe to 210-240 ℃ and keeping the temperature for 1-3 min; s2, uniformly spraying silane modified epoxy resin powder on the outer surface of the preheated steel pipe by adopting an electrostatic spraying process, so that the steel pipe is melted and leveled to reach a gel solidification state, and an epoxy bottom layer is formed; S3, when the temperature of the epoxy bottom layer is reduced to 100-150 ℃, using a co-extrusion winding device to melt and extrude silane modified maleic anhydride grafted polyethylene at 190-210 ℃ to serve as an intermediate layer; S4, continuously using co-extrusion winding equipment when the temperature of the middle layer is reduced to 150-180 ℃, and melting and extruding the fluorinated primary amine modified GMA grafted high-density polyethylene at 200-220 ℃ to serve as a surface layer, and winding and coating the surface of the middle layer to obtain a steel pipe with a three-layer composite structure; And S5, carrying out further heat treatment on the steel pipe with the three-layer composite structure, wherein the temperature is 170-200 ℃, the time is 30-90S, and cooling