Corrosion-resistant plastic alloy cable protection pipe and preparation method thereof

Abstract

The invention relates to the technical field of cable protection pipes, in particular to a corrosion-resistant plastic alloy cable protection pipe and a preparation method thereof. The preparation method of the corrosion-resistant plastic alloy cable protection pipe comprises the following steps: preparation of the functional corrosion-resistant filler, preparation of the composite antioxidant, preparation of the corrosion-resistant and antibacterial coating and preparation of the cable protection pipe. The performance of the pipe is improved through cooperation of multiple components. In the functional anticorrosive filler, boron nitride nanosheets form a labyrinth effect to prolong the permeation path of a corrosive medium, Zr-MOF adsorbs the corrosive medium, cerium oxide releases cerium ions to construct a chemical barrier, and multidirectional synergistic corrosion prevention is achieved. The composite antioxidant takes layered double hydroxide as a carrier, the antioxidant is dispersed to avoid agglomeration, free radicals are slowly released and continuously captured, and aging is delayed. In the anticorrosive and antibacterial coating, the nano silver molybdate resists microbial erosion, and the waterborne polyurethane forms a film to isolate a corrosive medium, so that the corrosion resistance is remarkably improved, and the service life is remarkably prolonged.

Description

Technical Field

[0001] This invention relates to the field of cable protection pipe manufacturing technology, specifically to a corrosion-resistant plastic alloy cable protection pipe and its manufacturing method. Background Technology

[0002] Cable protection pipes, as key supporting facilities in the power and communication industries, are mainly used to protect underground or open-air cables from damage caused by the external environment (such as soil corrosion, moisture erosion, mechanical impact, and microbial growth). Their performance directly affects the safe and stable operation of the cable system. With the acceleration of urbanization and the expansion of infrastructure construction, cable protection pipes are often used in complex and harsh environments such as humid, saline-alkali land, and industrial pollution areas, which places higher demands on their corrosion resistance, aging resistance, mechanical stability, and antibacterial properties.

[0003] Currently, most cable protection pipes on the market are made of single polyethylene (PE), polypropylene (PP), or simple blends thereof. While they possess certain insulation and processability, they still have significant drawbacks in complex environments. Traditional plastic pipes rely on their chemical inertness to resist corrosion, lacking an active protection mechanism. After long-term use, they are prone to aging and degradation due to chemical erosion, shortening their service life. Furthermore, polyolefin materials such as PE and PP are susceptible to oxidation chain reactions under the influence of light, heat, and oxygen, leading to molecular chain breakage and decreased mechanical properties. Although small-molecule antioxidants (such as hindered phenols) added in existing technologies can inhibit oxidation reactions, they are prone to aggregation due to poor compatibility and are easily volatilized or migrated during use, making it difficult to achieve long-term stable antioxidant effects. This results in accelerated aging rates of the pipes in outdoor or high-temperature environments. All these factors lead to a shortened service life of cable protection pipes, failing to provide long-term protection for the internal cables.

[0004] Therefore, this application aims to develop a corrosion-resistant plastic alloy cable protection pipe with high efficiency in corrosion prevention, long-term oxidation resistance, and long service life, as well as its preparation method, to solve the problems in the prior art. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a corrosion-resistant plastic alloy cable protection pipe and its preparation method.

[0006] This invention provides a method for preparing a corrosion-resistant plastic alloy cable protection pipe, comprising: S1: Preparation of functional anti-corrosion fillers; Zr-MOF powder was added to deionized water, followed by ethylene glycol and ammonia to prepare a mixed dispersion. Cerium nitrate was then added to the mixed dispersion, and the mixture was reacted to prepare a composite filler. The composite filler was then loaded onto boron nitride nanosheets to prepare a functional anti-corrosion filler. S2: Preparation of composite antioxidants; A layered double hydroxide was prepared using magnesium nitrate, aluminum nitrate, sodium hydroxide, and sodium bicarbonate as raw materials. Then, 3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-propionic acid was reacted with the layered double hydroxide as a raw material to prepare a composite antioxidant. S3: Preparation of anti-corrosion and antibacterial coatings; A polyvinylpyrrolidone dispersion of nano-silver molybdate was prepared, and then the polyvinylpyrrolidone dispersion of nano-silver molybdate was mixed with waterborne polyurethane to prepare a waterborne polyurethane coating modified with nano-silver molybdate, which is an anti-corrosion and antibacterial coating. S4: Preparation of cable protection pipes; A crude cable protection pipe is prepared using polyethylene, polypropylene, nano-calcium carbonate, functional anti-corrosion filler, compatibilizer, composite antioxidant, and plasticizer as raw materials. Then, it is coated with a nano-silver molybdate modified waterborne polyurethane coating and air-dried to obtain the cable protection pipe.

[0007] As a preferred aspect, S1: The preparation of the functional anti-corrosion filler specifically includes the following steps: S1.1: Add 0.5-0.8 parts by weight of Zr-MOF powder to 20-30 parts by weight of deionized water, then stir and mix at 150-200 rpm for 2-3 hours, then sonicate for 20-30 minutes, then add 20-30 parts by weight of ethylene glycol and 20-30 parts by weight of ammonia water, and stir for 20-30 minutes to obtain a mixed dispersion; S1.2: Add 1-2 parts by weight of cerium nitrate to the mixed dispersion, then add 90-100 parts by weight of deionized water, stir and mix at 200-300 rpm, and then put it into a reaction vessel. React the reaction vessel at 100-120℃ for 24-25 h. After cooling to room temperature, remove the supernatant, then centrifuge to obtain a precipitate. Wash the precipitate with deionized water and ethanol 2-3 times respectively. Dry the washed product at 60-62℃ for 12-14 h, then calcine at 430-450℃ for 3-4 h, grind and pulverize to obtain MOF composite filler; S1.3: Mix 2-3 parts by weight of MOF composite filler, 1-2 parts by weight of boron nitride nanosheets and 80-100 parts by weight of N,N-dimethylformamide, and then ultrasonically disperse for 1-2 hours. Then stir and disperse at 200-300 rpm for 2-3 hours. Centrifuge the dispersed solution and wash the centrifuged precipitate 2-3 times with deionized water and ethanol, respectively. Then dry at 60-62℃ for 12-14 hours to obtain the functional anti-corrosion filler.

[0008] As a preferred aspect, S2: the preparation of the composite antioxidant specifically includes the following steps: S2.1: Add 5-8 parts by weight of magnesium nitrate and 3-5 parts by weight of aluminum nitrate to 100-120 parts by weight of deionized water, stir and mix for 20-30 minutes to obtain a salt solution; add 2.4-2.8 parts by weight of sodium hydroxide and 2.1-2.3 parts by weight of sodium bicarbonate to 100-120 parts by weight of deionized water, stir and mix for 20-30 minutes to obtain an alkaline solution. S2.2: Add the salt solution and the alkaline solution to a three-necked flask at room temperature, and keep the pH value at 9.0-10.0. Stir and mix continuously for 1-2 hours. Then crystallize in a high-pressure reactor at 110-115℃ for 12-14 hours. After cooling, centrifugation, washing and drying, layered double hydroxide is obtained. S2.3: Add 1-2 parts by weight of layered double hydroxide to 100-120 parts by weight of DMF solution, and ultrasonically disperse for 30-40 min to obtain a layered double hydroxide dispersion. Add 2-3 parts by weight of 3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-propionic acid to 40-50 parts by weight of DMF solution, and heat to completely dissolve to obtain a 3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-propionic acid solution. S2.4: Add 3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-propionic acid solution to the layered double hydroxide dispersion, then add 1-2 parts by weight of p-toluenesulfonic acid, react at 60-62℃ for 24-25 h, wash 2-3 times with anhydrous ethanol after the reaction is completed, and dry to obtain the composite antioxidant.

[0009] As a preferred aspect, S3: the preparation of the anti-corrosion and antibacterial coating specifically includes the following steps: S3.1: Add 6-8 parts by weight of polyvinylpyrrolidone to 100-120 parts by weight of deionized water and stir until homogeneous. Then add 1-2 parts by weight of activator and stir until mixed. Add 5-6 parts by weight of nano silver molybdate and stir at 70-80℃ for 40-50 minutes to obtain a polyvinylpyrrolidone dispersion of nano silver molybdate. S3.2: Mix 10-12 parts by weight of polyvinylpyrrolidone dispersion of nano-silver molybdate with 50-60 parts by weight of waterborne polyurethane, then add 0.1-0.3 parts by weight of dimethyl silicone defoamer and stir for 5-10 minutes. Then add 1-2 parts by weight of dimethyl polysiloxane leveling agent and 2-3 parts by weight of propylene glycol butyl ether film-forming aid. Stir at 200-300 rpm for 20-30 minutes to obtain nano-silver molybdate modified waterborne polyurethane coating, which is an anti-corrosion and antibacterial coating.

[0010] As a preferred aspect, the activator in step S3.1 is sodium dodecylbenzenesulfonate.

[0011] As a preferred aspect, S4: the preparation of the cable protection conduit specifically includes the following steps: S4.1: After drying 50-60 parts by weight of polypropylene, 20-30 parts by weight of polyethylene, and 5-8 parts by weight of nano-calcium carbonate, transfer them to a mixer, heat and melt them, then add 10-12 parts by weight of functional anti-corrosion filler, 3-5 parts by weight of compatibilizer, and 1-2 parts by weight of plasticizer. Heat and stir to 170-190℃, mix and then cool to 90-100℃ and add 2-5 parts by weight of composite antioxidant. Mix and then extrude and granulate through a twin-screw extruder, cool and dry, and then extrude through a die to obtain the crude product of cable protection pipe. S4.2: Apply nano-silver molybdate modified waterborne polyurethane coating to the surface of the rough cable protection pipe with a coating thickness of 0.3-0.5 mm, and then air dry to obtain the cable protection pipe.

[0012] As a preferred aspect, the compatibilizer in step S4.1 is a combination of PP-g-MAH compatibilizer and POE-g-MAH compatibilizer in a mass ratio of 1:1.

[0013] As a preferred aspect, the plasticizer in step S4.1 is one of DOP, DINP, and DOTP.

[0014] The present invention also provides a corrosion-resistant plastic alloy cable protection pipe, which is prepared by any of the methods described in the present invention.

[0015] The present invention has the following advantages: 1. The functional anti-corrosion filler incorporated in this invention is composed of Zr-MOF-loaded cerium oxide and boron nitride nanosheets. The boron nitride nanosheets have a sheet-like structure, which can form a "maze effect" after being uniformly dispersed in the polymer matrix, significantly extending the penetration path of corrosive media and reducing its penetration rate into the matrix. This physically blocks the contact between the corrosive media and the matrix. The MOF composite filler loaded on the boron nitride nanosheets has a high specific surface area and abundant porous structure, which can actively adsorb corrosive media in the environment (such as water, chloride ions, acid and alkali ions, etc.), reducing their penetration and erosion of the polyethylene / polypropylene matrix and reducing the aging and degradation of the matrix caused by chemical corrosion. At the same time, the cerium oxide formed after the reaction and calcination of cerium nitrate acts as a corrosion inhibitor. In the corrosive environment, it can release cerium ions to build a chemical protective barrier on the surface or internal defects of the material, inhibiting the continuous corrosion reaction. Thus, it plays a synergistic role in corrosion prevention from multiple directions and angles.

[0016] 2. The composite antioxidant added in this invention uses layered double hydroxides as a carrier. These layered double hydroxides possess a unique layered structure and excellent dispersibility, enabling the uniform dispersion of the loaded 3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-propionic acid within polymer matrices such as polyethylene and polypropylene. This avoids the problem of easy aggregation of simple small-molecule antioxidants, ensuring that the antioxidant components fully contact polymer molecules within the pipe matrix, improving the coverage and efficiency of the antioxidant effect. The interlayer spaces of the layered double hydroxides can stably bind 3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-propionic acid. During the long-term use of the cable protection pipe, the antioxidant is slowly released, continuously capturing free radicals generated during polymer oxidation, inhibiting the oxidation chain reaction in the long term, significantly slowing down the aging rate of the pipe, and extending its service life.

[0017] 3. In the anti-corrosion and antibacterial coating of this invention, nano-silver molybdate is a highly efficient antibacterial ingredient. Cable protection pipes are often buried underground or exposed to humid environments, making them susceptible to substrate degradation or biocorrosion due to microbial growth. This coating can block microbial erosion of the protection pipe from the source, extending its service life. Furthermore, the addition of nano-silver molybdate, due to its much smaller size than the polyurethane matrix, can fill the gaps between polyurethane molecules, weakening capillary action and further reducing the coating's water absorption rate. This effectively isolates external water, oxygen, soil salts, acids, alkalis, and other corrosive media from contacting the protective pipe substrate, preventing the substrate from being damaged by oxidation or chemical corrosion. The corrosion resistance of the protective tube is significantly improved, preventing aging or damage caused by corrosion. Furthermore, nano-silver molybdate can form micro- and nano-structures on the surface of water-based polyurethane. These micro- and nano-structures reduce the contact area of ​​water on the surface and increase the roughness of the coating, further improving the hydrophobicity of the cable protection surface coating. The hydrophobic surface is less prone to water residue, which can reduce "freeze-thaw damage" caused by water freezing in low-temperature environments. At the same time, the hydrophobic properties can reduce the risk of swelling and aging of the coating in high humidity or rainy environments where it is in a wet state for a long time, ensuring the physical protection of the cable by the coating, thereby effectively extending the service life of the protective tube in complex environments. Attached Figure Description

[0018] Figure 1 This is a process flow diagram of a method for preparing a corrosion-resistant plastic alloy cable protection pipe according to an embodiment of the present invention.

[0019] Figure 2 This is a SEM image of the MOF composite filler of the present invention.

[0020] Figure 3 This is a SEM image of the functional anti-corrosion filler of the present invention. Detailed Implementation

[0021] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of this invention.

[0022] Example 1: A method for preparing a corrosion-resistant plastic alloy cable protection pipe, referring to... Figure 1 ,include: S1: Preparation of functional anti-corrosion fillers S1.1: Add 0.5 parts by weight of Zr-MOF powder to 20 parts by weight of deionized water, then stir and mix at 150 rpm for 2 hours, then sonicate for 20 minutes, then add 20 parts by weight of ethylene glycol and 20 parts by weight of ammonia water, mix and stir for 20 minutes to obtain a mixed dispersion. S1.2: Add 1 part by weight of cerium nitrate to the mixed dispersion, then add 90 parts by weight of deionized water, stir and mix at 200 rpm, then put into a reaction vessel, react at 100℃ for 24 h, cool to room temperature, remove the supernatant, then centrifuge to obtain a precipitate, wash the precipitate twice with deionized water and ethanol respectively, dry the washed product at 60℃ for 12 h, then calcine at 430℃ for 3 h, grind and pulverize to obtain MOF composite filler; S1.3: Mix 2 parts by weight of MOF composite filler, 1 part by weight of boron nitride nanosheets and 80 parts by weight of N,N-dimethylformamide, then ultrasonically disperse for 1 h, and then stir and disperse at 200 rpm for 2 h. Centrifuge the dispersed solution, wash the centrifuged precipitate twice with deionized water and ethanol respectively, and then dry at 60℃ for 12 h to obtain the functional anti-corrosion filler. S2: Preparation of composite antioxidants S2.1: Add 5 parts by weight of magnesium nitrate and 3 parts by weight of aluminum nitrate to 100 parts by weight of deionized water, stir and mix for 20 minutes to obtain a salt solution; add 2.4 parts by weight of sodium hydroxide and 2.1 parts by weight of sodium bicarbonate to 100 parts by weight of deionized water, stir and mix for 20 minutes to obtain an alkaline solution. S2.2: Add the salt solution and the alkaline solution to a three-necked flask at room temperature, keep the pH at 9.0, and stir continuously for 1 hour. Then, crystallize in a high-pressure reactor at 110°C for 12 hours, cool, centrifuge, wash, and dry to obtain layered double hydroxides. S2.3: Add 1 part by weight of layered double hydroxide to 100 parts by weight of DMF solution, and sonicate for 30 min to obtain a layered double hydroxide dispersion. Add 2 parts by weight of 3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-propionic acid to 40 parts by weight of DMF solution, and heat to completely dissolve to obtain a 3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-propionic acid solution. S2.4: 3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-propionic acid solution was added to the layered double hydroxide dispersion, followed by 1 part by weight of p-toluenesulfonic acid. The mixture was reacted at 60°C for 24 h. After the reaction was completed, the mixture was washed twice with anhydrous ethanol and dried to obtain the composite antioxidant. S3: Preparation of anti-corrosion and antibacterial coatings S3.1: Add 6 parts by weight of polyvinylpyrrolidone to 100 parts by weight of deionized water and stir until homogeneous. Then add 1 part by weight of sodium dodecylbenzenesulfonate as an active agent and stir until mixed. Then add 5 parts by weight of nano silver molybdate and stir at 70°C for 40 min to obtain a polyvinylpyrrolidone dispersion of nano silver molybdate. S3.2: Mix 10 parts by weight of polyvinylpyrrolidone dispersion of nano-silver molybdate and 50 parts by weight of waterborne polyurethane, then add 0.1 parts by weight of dimethyl silicone defoamer and stir for 5 min, then add 1 part by weight of dimethyl polysiloxane leveling agent and 2 parts by weight of propylene glycol butyl ether film-forming aid, and then stir at 200 rpm for 20 min to obtain nano-silver molybdate modified waterborne polyurethane coating, which is an anti-corrosion and antibacterial coating. S4: Preparation of cable protection pipes S4.1: 30 parts by weight of polyethylene, 20 parts by weight of polypropylene, and 5 parts by weight of nano-calcium carbonate are dried and transferred to a mixer. After heating and melting, 10 parts by weight of functional anti-corrosion filler, 3 parts by weight of compatibilizer, and 1 part by weight of plasticizer DOP are added. The mixture is heated and stirred to 170°C. After stirring and mixing, the mixture is cooled to 90°C and 2 parts by weight of composite antioxidant are added. The mixture is stirred and mixed, and then extruded and granulated through a twin-screw extruder. After cooling and drying, the mixture is extruded through a die to obtain the crude product of cable protection pipe. The compatibilizer is obtained by combining PP-g-MAH compatibilizer and POE-g-MAH compatibilizer in a mass ratio of 1:1; S4.2: Apply nano-silver molybdate modified waterborne polyurethane coating to the surface of the rough cable protection pipe with a coating thickness of 0.3 mm, and then air dry to obtain the cable protection pipe.

[0023] Example 2, a method for preparing a corrosion-resistant plastic alloy cable protection pipe, see [link to example]. Figure 1 ,include: S1: Preparation of functional anti-corrosion fillers S1.1: Add 0.5 parts by weight of Zr-MOF powder to 20 parts by weight of deionized water, then stir and mix at 200 rpm for 3 h, then sonicate for 30 min, then add 20 parts by weight of ethylene glycol and 20 parts by weight of ammonia water, mix and stir for 30 min to obtain a mixed dispersion. S1.2: Add 1 part by weight of cerium nitrate to the mixed dispersion, then add 90 parts by weight of deionized water, stir and mix at 300 rpm, then put into a reaction vessel, react at 120℃ for 25 h, cool to room temperature, remove the supernatant, then centrifuge to obtain the precipitate, wash the precipitate three times with deionized water and ethanol respectively, dry the washed product at 62℃ for 14 h, then calcine at 450℃ for 4 h, grind and pulverize to obtain MOF composite filler; S1.3: Mix 2 parts by weight of MOF composite filler, 1 part by weight of boron nitride nanosheets and 80 parts by weight of N,N-dimethylformamide, and then ultrasonically disperse for 2 hours. Then stir and disperse at 300 rpm for 3 hours. Centrifuge the dispersed solution and wash the centrifuged precipitate three times with deionized water and ethanol respectively. Then dry at 62℃ for 14 hours to obtain the functional anti-corrosion filler. S2: Preparation of composite antioxidants S2.1: Add 5 parts by weight of magnesium nitrate and 3 parts by weight of aluminum nitrate to 100 parts by weight of deionized water, stir and mix for 30 minutes to obtain a salt solution; add 2.4 parts by weight of sodium hydroxide and 2.1 parts by weight of sodium bicarbonate to 100 parts by weight of deionized water, stir and mix for 30 minutes to obtain an alkaline solution. S2.2: Salt solution and alkaline solution were added to a three-necked flask at room temperature, and the pH value was kept at 9.0. The mixture was stirred and mixed for 2 hours. After crystallization in a high-pressure reactor at 115℃ for 14 hours, the mixture was cooled, centrifuged, washed, and dried to obtain layered double hydroxides. S2.3: Add 1 part by weight of layered double hydroxide to 100 parts by weight of DMF solution, and sonicate for 40 min to obtain a layered double hydroxide dispersion. Add 2 parts by weight of 3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-propionic acid to 40 parts by weight of DMF solution, and heat to completely dissolve to obtain a 3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-propionic acid solution. S2.4: 3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-propionic acid solution was added to the layered double hydroxide dispersion, followed by 1 part by weight of p-toluenesulfonic acid. The mixture was reacted at 62°C for 25 h. After the reaction was completed, the mixture was washed three times with anhydrous ethanol and dried to obtain the composite antioxidant. S3: Preparation of anti-corrosion and antibacterial coatings S3.1: Add 6 parts by weight of polyvinylpyrrolidone to 100 parts by weight of deionized water and stir until homogeneous. Then add 1 part by weight of sodium dodecylbenzenesulfonate as an active agent and stir until mixed. Then add 5 parts by weight of nano silver molybdate and stir at 80°C for 50 min to obtain a polyvinylpyrrolidone dispersion of nano silver molybdate. S3.2: Mix 10 parts by weight of polyvinylpyrrolidone dispersion of nano-silver molybdate and 50 parts by weight of waterborne polyurethane, then add 0.1 parts by weight of dimethyl silicone defoamer and stir for 10 min, then add 1 part by weight of dimethyl polysiloxane leveling agent and 2 parts by weight of propylene glycol butyl ether film-forming aid, and then stir at 300 rpm for 30 min to obtain nano-silver molybdate modified waterborne polyurethane coating, which is an anti-corrosion and antibacterial coating. S4: Preparation of cable protection pipes S4.1: 30 parts by weight of polyethylene, 20 parts by weight of polypropylene, and 5 parts by weight of nano-calcium carbonate are dried and transferred to a mixer. After heating and melting, 10 parts by weight of functional anti-corrosion filler, 3 parts by weight of polypropylene grafted maleic anhydride compatibilizer, and 1 part by weight of plasticizer DINP are added. The mixture is heated and stirred to 190°C. After stirring and mixing, the mixture is cooled to 100°C and 2 parts by weight of composite antioxidant are added. The mixture is stirred and mixed, and then extruded and granulated through a twin-screw extruder. After cooling and drying, the mixture is extruded through a die to obtain a crude cable protection pipe. The compatibilizer is obtained by combining PP-g-MAH compatibilizer and POE-g-MAH compatibilizer in a mass ratio of 1:1; S4.2: Apply nano-silver molybdate modified waterborne polyurethane coating to the surface of the rough cable protection pipe with a coating thickness of 0.3 mm, and then air dry to obtain the cable protection pipe.

[0024] Example 3: A method for preparing a corrosion-resistant plastic alloy cable protection pipe, see [link to example]. Figure 1 ,include: S1: Preparation of functional anti-corrosion fillers S1.1: Add 0.8 parts by weight of Zr-MOF powder to 30 parts by weight of deionized water, then stir and mix at 150 rpm for 2 h, then sonicate for 20 min, then add 30 parts by weight of ethylene glycol and 30 parts by weight of ammonia water, mix and stir for 20 min to obtain a mixed dispersion. S1.2: Add 2 parts by weight of cerium nitrate to the mixed dispersion, then add 100 parts by weight of deionized water, stir and mix at 200 rpm, and then put it into a reaction vessel. React the reaction vessel at 100℃ for 24 h. After cooling to room temperature, remove the supernatant, then centrifuge to obtain the precipitate. Wash the precipitate three times with deionized water and ethanol respectively. Dry the washed product at 62℃ for 14 h, then calcine at 430℃ for 4 h, grind and pulverize to obtain MOF composite filler; S1.3: Mix 3 parts by weight of MOF composite filler, 2 parts by weight of boron nitride nanosheets and 100 parts by weight of N,N-dimethylformamide, and then ultrasonically disperse for 2 hours. Then stir and disperse at 300 rpm for 3 hours. Centrifuge the dispersed solution and wash the centrifuged precipitate three times with deionized water and ethanol respectively. Then dry at 62℃ for 14 hours to obtain the functional anti-corrosion filler. S2: Preparation of composite antioxidants S2.1: Add 5 parts by weight of magnesium nitrate and 3 parts by weight of aluminum nitrate to 100 parts by weight of deionized water, stir and mix for 30 minutes to obtain a salt solution; add 2.4 parts by weight of sodium hydroxide and 2.1 parts by weight of sodium bicarbonate to 100 parts by weight of deionized water, stir and mix for 30 minutes to obtain an alkaline solution. S2.2: Add the salt solution and the alkaline solution to a three-necked flask at room temperature, keep the pH at 10.0, and stir continuously for 1 hour. Then, crystallize in a high-pressure reactor at 110°C for 12 hours, cool, centrifuge, wash, and dry to obtain layered double hydroxides. S2.3: Add 2 parts by weight of layered double hydroxide to 120 parts by weight of DMF solution, and sonicate for 30 min to obtain a layered double hydroxide dispersion. Add 3 parts by weight of 3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-propionic acid to 50 parts by weight of DMF solution, and heat to completely dissolve to obtain a 3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-propionic acid solution. S2.4: 3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-propionic acid solution was added to the layered double hydroxide dispersion, followed by 2 parts by weight of p-toluenesulfonic acid. The mixture was reacted at 60°C for 24 h. After the reaction was completed, the mixture was washed twice with anhydrous ethanol and dried to obtain the composite antioxidant. S3: Preparation of anti-corrosion and antibacterial coatings S3.1: Add 8 parts by weight of polyvinylpyrrolidone to 120 parts by weight of deionized water and stir until homogeneous. Then add 2 parts by weight of sodium dodecylbenzenesulfonate as an active agent and stir until mixed. Then add 6 parts by weight of nano-silver molybdate and stir at 70°C for 40 min to obtain a polyvinylpyrrolidone dispersion of nano-silver molybdate. S3.2: Mix 12 parts by weight of polyvinylpyrrolidone dispersion of nano-silver molybdate and 60 parts by weight of waterborne polyurethane, then add 0.3 parts by weight of dimethyl silicone defoamer and stir for 5 min, then add 2 parts by weight of dimethyl polysiloxane leveling agent and 3 parts by weight of propylene glycol butyl ether film-forming aid, and then stir at 200 rpm for 20 min to obtain nano-silver molybdate modified waterborne polyurethane coating, which is an anti-corrosion and antibacterial coating; S4: Preparation of cable protection pipes S4.1: 40 parts by weight of polyethylene, 30 parts by weight of polypropylene, and 8 parts by weight of nano-calcium carbonate are dried and transferred to a mixer. After heating and melting, 12 parts by weight of functional anti-corrosion filler, 5 parts by weight of polypropylene grafted maleic anhydride compatibilizer, and 2 parts by weight of plasticizer DOTP are added. The mixture is heated and stirred to 170°C. After stirring and mixing, the mixture is cooled to 90°C and 5 parts by weight of composite antioxidant are added. The mixture is stirred and mixed, and then extruded and granulated through a twin-screw extruder. After cooling and drying, the mixture is extruded through a die to obtain the crude product of cable protection pipe. The compatibilizer is obtained by combining PP-g-MAH compatibilizer and POE-g-MAH compatibilizer in a mass ratio of 1:1; S4.2: Apply nano-silver molybdate modified waterborne polyurethane coating to the surface of the rough cable protection pipe with a coating thickness of 0.5 mm, and then air dry to obtain the cable protection pipe.

[0025] Comparative Example 1 differs from Example 1 in that step S1.3 is removed, and the functional anti-corrosion filler in step S4.1 is replaced with MOF composite filler. The remaining steps are unchanged in the preparation of the cable protection pipe. This is referred to as Comparative Example 1.

[0026] Comparative Example 2 differs from Example 1 in that the functional anti-corrosion filler in step S4.1 is replaced with boron nitride nanosheets, while the remaining steps remain unchanged in the preparation of the cable protection tube. This is referred to as Comparative Example 2.

[0027] Comparative Example 3 differs from Example 1 in that steps S1.1-S1.2 are removed, and the MOF composite filler in step S1.3 is replaced with Zr-MOF powder, while the remaining steps remain unchanged in the preparation of the cable protection tube. This is referred to as Comparative Example 3.

[0028] Comparative Example 4 differs from Example 1 in that step S2 is removed and the composite antioxidant in step S4.1 is replaced with 3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-propionic acid, while the remaining steps remain unchanged in the preparation of the cable protection tube. This is referred to as Comparative Example 4.

[0029] Comparative Example 5 differs from Example 1 in that step S3 is removed, and the nano-silver molybdate modified waterborne polyurethane coating in step S4.2 is replaced with a waterborne polyurethane coating, while the remaining steps remain unchanged in the preparation of the cable protection tube. This is referred to as Comparative Example 5.

[0030] The performance of the cable protection pipes prepared in Examples 1-3 was tested three times, and the average value was taken. The test results are shown in Table 1.

[0031] Table 1. Performance Testing of Cable Protection Pipes in Examples 1-3 Tensile strength (MPa) Elongation at break (%) Example 1 86.3 382.23 Example 2 85.2 378.22 Example 3 85.6 379.42 As can be seen from the data in Table 1, the cable protection pipe prepared by this invention has good mechanical properties.

[0032] The aging resistance of the cable protection pipes prepared in Examples 1-3 and Comparative Example 4 were tested three times, and the average value was taken. The test results are shown in Table 2.

[0033] Table 2. Determination of oxidation aging resistance of cable protection pipes in Examples 1-3 and Comparative Example 4 Change rate of tensile strength (%) after aging at 158℃ for 168h Change in elongation at break (%) after aging at 158℃ for 168h Change rate of tensile strength (%) after aging at 158℃ for 1000h Change in elongation at break (%) after aging at 158℃ for 1000 hours Example 1 -3 -9 -8 -13 Example 2 -4 -8 -8 -14 Example 3 -4 -9 -9 -15 Comparative Example 4 -11 -17 -39 -43 As can be seen from the data in Table 2, the addition of composite antioxidants in this invention can improve the antioxidant capacity, significantly delay the aging of pipes, and achieve long-lasting antioxidant aging effect, thus extending service life.

[0034] The cable protection pipes prepared in Examples 1-3 and Comparative Examples 1-3 and 5 were tested for hydrolytic corrosion resistance at 80°C for 168 hours. The tests were conducted three times and the average value was taken. The test results are shown in Table 3.

[0035] Table 3. Hydrolytic corrosion resistance test results of Examples 1-3 and Comparative Examples 1-3, 5 Change rate of tensile strength (%) Change in elongation at break (%) Example 1 -5 -13 Example 2 -6 -14 Example 3 -5 -14 Comparative Example 1 -16 -21 Comparative Example 2 -23 -32 Comparative Example 3 -19 -26 Comparative Example 5 -13 -19 The acid corrosion resistance of the cable protection pipes prepared in Examples 1-3 and Comparative Examples 1-3 and 5 was tested at 23°C for 168 hours. The test was conducted three times and the average value was taken. The test results are shown in Table 4.

[0036] Table 4. Determination of acid corrosion resistance of Examples 1-3 and Comparative Examples 1-3, 5 Change rate of tensile strength (%) Change in elongation at break (%) Example 1 -8 -15 Example 2 -9 -16 Example 3 -8 -15 Comparative Example 1 -19 -23 Comparative Example 2 -25 -35 Comparative Example 3 -22 -27 Comparative Example 5 -14 -22 The cable protection pipes prepared in Examples 1-3 and Comparative Examples 1-3 and 5 were tested for alkali corrosion resistance at 23°C for 168 hours. The tests were conducted three times and the average value was taken. The test results are shown in Table 5.

[0037] Table 5. Alkali corrosion resistance test results of Examples 1-3 and Comparative Examples 1-3, 5 Change rate of tensile strength (%) Change in elongation at break (%) Example 1 -9 -14 Example 2 -7 -15 Example 3 -8 -14 Comparative Example 1 -18 -24 Comparative Example 2 -26 -35 Comparative Example 3 -21 -28 Comparative Example 5 -16 -23 As can be seen from the data in Tables 3-5, the cable protection pipe prepared by this invention has excellent corrosion resistance. As can be seen from the data in Comparative Examples 1-2, the added functional anti-corrosion filler can significantly reduce the penetration and erosion of corrosive media into the matrix, reduce the aging and degradation of the matrix caused by chemical corrosion, and the functional anti-corrosion filler composed of Zr-MOF loaded cerium oxide and boron nitride nanosheets has a better anti-corrosion effect than MOF composite filler and Zr-MOF / boron nitride nanosheets. As can be seen from the data in Comparative Example 5, the addition of nano silver molybdate anti-corrosion and antibacterial coating can significantly improve the corrosion resistance of the protection pipe.

[0038] The coatings of Examples 1-3 and Comparative Example 5 were tested for performance. The tests were conducted three times, and the average value was taken. The test results are shown in Table 6.

[0039] Table 6. Performance test results of Examples 1-3 and Comparative Example 5 Water absorption rate (%) Antibacterial rate of Escherichia coli (%) Antibacterial rate against Staphylococcus aureus (%) Contact angle (°) Example 1 2.4 99.9 99.9 87.4 Example 2 2.5 99.9 99.9 89.5 Example 3 2.4 99.9 99.9 88.3 Comparative Example 5 22.3 <5.00 <5.00 70.1 As can be seen from the data in Table 6, the addition of nano-silver molybdate in this invention can significantly reduce the water absorption rate of the coating and increase its hydrophobicity, effectively extending the service life of the protective tube in complex environments, while also giving the coating excellent antibacterial properties.

[0040] from Figures 2-3 It can be seen that cerium oxide was successfully loaded onto Zr-MOF, and MOF composite filler was loaded onto the surface of boron nitride nanosheets.

[0041] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims. Parts not described in detail in this specification are prior art known to those skilled in the art.

Claims

1. A method for preparing a corrosion-resistant plastic alloy cable protection pipe, characterized in that, include: S1: Preparation of functional anti-corrosion fillers; Zr-MOF powder was added to deionized water, followed by ethylene glycol and ammonia to prepare a mixed dispersion. Cerium nitrate was then added to the mixed dispersion, and the mixture was reacted to prepare a composite filler. The composite filler was then loaded onto boron nitride nanosheets to prepare a functional anti-corrosion filler. S2: Preparation of composite antioxidants; A layered double hydroxide was prepared using magnesium nitrate, aluminum nitrate, sodium hydroxide, and sodium bicarbonate as raw materials. Then, 3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-propionic acid was reacted with the layered double hydroxide as a raw material to prepare a composite antioxidant. S3: Preparation of anti-corrosion and antibacterial coatings; A polyvinylpyrrolidone dispersion of nano-silver molybdate was prepared, and then the polyvinylpyrrolidone dispersion of nano-silver molybdate was mixed with waterborne polyurethane to prepare a waterborne polyurethane coating modified with nano-silver molybdate, which is an anti-corrosion and antibacterial coating. S4: Preparation of cable protection pipes; A crude cable protection pipe is prepared using polyethylene, polypropylene, nano-calcium carbonate, functional anti-corrosion filler, compatibilizer, composite antioxidant, and plasticizer as raw materials. Then, it is coated with a nano-silver molybdate modified waterborne polyurethane coating and air-dried to obtain the cable protection pipe.

2. The method for preparing a corrosion-resistant plastic alloy cable protection pipe according to claim 1, characterized in that, S1: The preparation of functional anti-corrosion fillers includes the following steps: S1.1: Add 0.5-0.8 parts by weight of Zr-MOF powder to 20-30 parts by weight of deionized water, then stir and mix at 150-200 rpm for 2-3 hours, then sonicate for 20-30 minutes, then add 20-30 parts by weight of ethylene glycol and 20-30 parts by weight of ammonia water, and stir for 20-30 minutes to obtain a mixed dispersion; S1.2: Add 1-2 parts by weight of cerium nitrate to the mixed dispersion, then add 90-100 parts by weight of deionized water, stir and mix at 200-300 rpm, and then put it into a reaction vessel. React the reaction vessel at 100-120℃ for 24-25 h. After cooling to room temperature, remove the supernatant, then centrifuge to obtain a precipitate. Wash the precipitate with deionized water and ethanol 2-3 times respectively. Dry the washed product at 60-62℃ for 12-14 h, then calcine at 430-450℃ for 3-4 h, grind and pulverize to obtain MOF composite filler; S1.3: Mix 2-3 parts by weight of MOF composite filler, 1-2 parts by weight of boron nitride nanosheets and 80-100 parts by weight of N,N-dimethylformamide, and then ultrasonically disperse for 1-2 hours. Then stir and disperse at 200-300 rpm for 2-3 hours. Centrifuge the dispersed solution and wash the centrifuged precipitate 2-3 times with deionized water and ethanol, respectively. Then dry at 60-62℃ for 12-14 hours to obtain the functional anti-corrosion filler.

3. The method for preparing a corrosion-resistant plastic alloy cable protection pipe according to claim 2, characterized in that, S2: the preparation of the composite antioxidant specifically includes the following steps: S2.1: Add 5-8 parts by weight of magnesium nitrate and 3-5 parts by weight of aluminum nitrate to 100-120 parts by weight of deionized water, stir and mix for 20-30 minutes to obtain a salt solution; add 2.4-2.8 parts by weight of sodium hydroxide and 2.1-2.3 parts by weight of sodium bicarbonate to 100-120 parts by weight of deionized water, stir and mix for 20-30 minutes to obtain an alkaline solution. S2.2: Add the salt solution and the alkaline solution to a three-necked flask at room temperature, and keep the pH value at 9.0-10.

0. Stir and mix continuously for 1-2 hours. Then crystallize in a high-pressure reactor at 110-115℃ for 12-14 hours. After cooling, centrifugation, washing and drying, layered double hydroxide is obtained. S2.3: Add 1-2 parts by weight of layered double hydroxide to 100-120 parts by weight of DMF solution, and ultrasonically disperse for 30-40 min to obtain a layered double hydroxide dispersion. Add 2-3 parts by weight of 3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-propionic acid to 40-50 parts by weight of DMF solution, and heat to completely dissolve to obtain a 3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-propionic acid solution. S2.4: Add 3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-propionic acid solution to the layered double hydroxide dispersion, then add 1-2 parts by weight of p-toluenesulfonic acid, react at 60-62℃ for 24-25 h, wash 2-3 times with anhydrous ethanol after the reaction is completed, and dry to obtain the composite antioxidant.

4. The method for preparing a corrosion-resistant plastic alloy cable protection pipe according to claim 3, characterized in that, S3: The preparation of the anti-corrosion and antibacterial coating includes the following steps: S3.1: Add 6-8 parts by weight of polyvinylpyrrolidone to 100-120 parts by weight of deionized water and stir until homogeneous. Then add 1-2 parts by weight of activator and stir until mixed. Add 5-6 parts by weight of nano silver molybdate and stir at 70-80℃ for 40-50 minutes to obtain a polyvinylpyrrolidone dispersion of nano silver molybdate. S3.2: Mix 10-12 parts by weight of polyvinylpyrrolidone dispersion of nano-silver molybdate with 50-60 parts by weight of waterborne polyurethane, then add 0.1-0.3 parts by weight of dimethyl silicone defoamer and stir for 5-10 minutes. Then add 1-2 parts by weight of dimethyl polysiloxane leveling agent and 2-3 parts by weight of propylene glycol butyl ether film-forming aid. Stir at 200-300 rpm for 20-30 minutes to obtain nano-silver molybdate modified waterborne polyurethane coating, which is an anti-corrosion and antibacterial coating.

5. The method for preparing a corrosion-resistant plastic alloy cable protection pipe according to claim 3, characterized in that, The active agent in step S3.1 is sodium dodecylbenzenesulfonate.

6. The method for preparing a corrosion-resistant plastic alloy cable protection pipe according to claim 4, characterized in that, S4: The preparation of cable protection pipes includes the following steps: S4.1: After drying 50-60 parts by weight of polypropylene, 20-30 parts by weight of polyethylene, and 5-8 parts by weight of nano-calcium carbonate, transfer them to a mixer, heat and melt them, then add 10-12 parts by weight of functional anti-corrosion filler, 3-5 parts by weight of compatibilizer, and 1-2 parts by weight of plasticizer. Heat and stir to 170-190℃, mix and then cool to 90-100℃ and add 2-5 parts by weight of composite antioxidant. Mix and then extrude and granulate through a twin-screw extruder, cool and dry, and then extrude through a die to obtain the crude product of cable protection pipe. S4.2: Apply nano-silver molybdate modified waterborne polyurethane coating to the surface of the rough cable protection pipe with a coating thickness of 0.3-0.5 mm, and then air dry to obtain the cable protection pipe.

7. The method for preparing a corrosion-resistant plastic alloy cable protection pipe according to claim 6, characterized in that, The compatibilizer in step S4.1 is obtained by combining PP-g-MAH compatibilizer and POE-g-MAH compatibilizer in a mass ratio of 1:

1.

8. The method for preparing a corrosion-resistant plastic alloy cable protection pipe according to claim 6, characterized in that, The plasticizer in step S4.1 is one of DOP, DINP, or DOTP.

9. A corrosion-resistant plastic alloy cable protection pipe, characterized in that, It is prepared by the method for preparing a corrosion-resistant plastic alloy cable protection pipe according to any one of claims 1-8.

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