Corrosion-resistant mpp power cable protection pipe and preparation method and application thereof
Patent Information
- Application Number
- CN202610886757.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-18
- Publication Date
- 2026-09-15
Smart Images
Figure CN122747432A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of power cable protection pipe technology, and in particular to a corrosion-resistant MPP power cable protection pipe, its preparation method and application. Background Technology
[0002] Power cable protection pipes are an important infrastructure for ensuring the safe operation of the power grid. Traditional cable protection pipes mainly use steel pipes, cement pipes, ordinary polyethylene pipes, and ordinary polypropylene pipes, but these materials all have obvious shortcomings in use: steel pipes are heavy and prone to corrosion; cement pipes are brittle and prone to cracking; ordinary PE pipes have poor heat resistance and are prone to softening and deformation when the cable heats up; and ordinary PP pipes have poor low-temperature impact resistance.
[0003] Modified polypropylene (MPP) power cable protection pipes are widely used in municipal, telecommunications, and power pipeline projects due to their excellent electrical insulation, high heat distortion temperature, good tensile and compressive strength, and convenient construction. They can cross roads, riverbeds, and other areas where excavation is not advisable, avoiding traffic congestion and environmental impact caused by traditional trenching and pipe burial methods.
[0004] However, existing MPP power cable protection pipes still have the following shortcomings in practical applications: when facing humid and complex environments such as rivers and drainage areas, the pipes are easily corroded by environmental media, accelerating corrosion and aging, and shortening service life; while adding rigid fillers to improve strength, it often leads to a decrease in pipe toughness, making it prone to brittle fracture; traditional single-layer pipes cannot simultaneously meet the requirements of corrosion resistance, mechanical properties, and service life; although existing MPP pipes have better heat resistance than PE, they still have problems such as insufficient Vicat softening temperature (usually only around 150℃) and significant decrease in ring stiffness with temperature under continuous cable heating or high-temperature environments.
[0005] Therefore, developing an MPP power cable protection pipe that combines high heat resistance, excellent corrosion resistance, and a good balance of rigidity and toughness is of great practical significance. Summary of the Invention
[0006] The purpose of this invention is to provide a corrosion-resistant MPP power cable protection pipe, its preparation method and application. The MPP power cable protection pipe provided by this invention has high heat resistance, excellent corrosion resistance and good rigidity-toughness balance.
[0007] To achieve the above objectives, the present invention provides a corrosion-resistant MPP power cable protection pipe, comprising an inner tube layer and an outer tube layer. By weight, the outer tube layer comprises the following components: 50-72 parts random copolymer polypropylene; 14-28 parts homopolymer polypropylene; 8-12 parts fluororubber; 3-6 parts silane coupling agent modified nano-silica; 6-14 parts nano-calcium carbonate; 5-8 parts compatibilizer; 1-3 parts antioxidant; 0.5-1.5 parts UV absorber; and 2.5-4 parts lubricant. By weight, the inner tube layer comprises the following components: 55-80 parts random copolymer polypropylene; 15-40 parts homopolymer polypropylene; 2-5 parts silane coupling agent modified nano-silica; 6-10 parts nano-calcium carbonate; 5-8 parts compatibilizer; 1-2 parts antioxidant; and 1-2.5 parts lubricant.
[0008] In this invention, in the outer tube layer, the ethylene content of the random copolymer polypropylene is preferably 1% to 4% by mass; the melt index of the homopolymer polypropylene is preferably 0.9 to 6 g / 10 min; in the inner tube layer, the ethylene content of the random copolymer polypropylene is preferably 1% to 4% by mass; the melt index of the homopolymer polypropylene is preferably 0.9 to 6 g / 10 min.
[0009] In this invention, the silane coupling agent for the silane coupling agent-modified nano-silica in the outer tube layer and the inner tube layer is preferably KH570; the preparation method of the silane coupling agent-modified nano-silica preferably includes the following steps: (1) After drying the nano-silica to remove water, add it to ethanol and disperse it by ultrasonication to obtain a nano-silica suspension; (2) Add the silane coupling agent to the ethanol solution, adjust the pH value, and hydrolyze to obtain the silane coupling agent hydrolysate; (3) The silane coupling agent hydrolysate is slowly added dropwise into the nano silica suspension, stirred in a water bath, centrifuged, washed, vacuum dried, ground and sieved to obtain silane coupling agent modified nano silica.
[0010] In this invention, in step (1), the drying temperature is preferably 100~120℃ and the time is preferably 2~4h; the ultrasonic dispersion time is preferably 20~40min; and the mass concentration of the nano silica suspension is preferably 5%~15%.
[0011] In this invention, in step (2), the silane coupling agent is preferably KH570, and the mass of KH570 is preferably 2% to 10% of the mass of nano-silica; the pH value is preferably adjusted by acetic acid, and the pH value is preferably 3.5 to 4.5; the hydrolysis temperature is preferably 20 to 30°C, and the time is preferably 30 to 60 minutes.
[0012] In this invention, in step (3), the water bath stirring temperature is preferably 50~70℃ and the time is preferably 2~6h; the centrifugation speed is preferably 4000~5000rpm and the time is preferably 15~20min; the washing is preferably done with ethanol; the vacuum drying temperature is preferably 80~100℃ and the time is preferably 8~12h; and the grinding and sieving is preferably done through a 200-mesh sieve.
[0013] In this invention, the fluororubber is preferably a vinylidene fluoride-hexafluoropropylene copolymer; the Mooney viscosity of the fluororubber is preferably 40-60, and the weight-average molecular weight is preferably 100,000-200,000.
[0014] In this invention, in the outer tube layer, the antioxidant preferably includes antioxidant 1010 and antioxidant 626; the mass ratio of antioxidant 1010 to antioxidant 626 is preferably 1:1 to 1.5; in the inner tube layer, the antioxidant preferably includes antioxidant 1010 and antioxidant 626; the mass ratio of antioxidant 1010 to antioxidant 626 is preferably 1:1 to 1.5.
[0015] In this invention, the UV absorber is preferably one of UV-326, UV-329, and UV-928.
[0016] In this invention, the compatibilizer in the outer tube layer is preferably one of maleic anhydride-grafted polypropylene and maleic anhydride-grafted ethylene-octene copolymer; the compatibilizer in the inner tube layer is preferably one of maleic anhydride-grafted polypropylene and maleic anhydride-grafted ethylene-octene copolymer.
[0017] In this invention, the lubricant in the outer tube layer is polypropylene wax, paraffin wax, stearic acid, or zinc stearate; and the lubricant in the inner tube layer is polypropylene wax, paraffin wax, stearic acid, or zinc stearate.
[0018] The present invention does not impose any particular restrictions on the source of the above-mentioned raw materials; conventional commercially available products known to those skilled in the art can be used.
[0019] This invention also provides a method for preparing the above-mentioned corrosion-resistant MPP power cable protection pipe, comprising the following steps: S1: Weigh the raw material components of the outer tube layer and the inner tube layer according to the proportion, and put them into the high-speed mixer to mix evenly to obtain the outer tube mixture and the inner tube mixture. S2: The outer tube mixture and the inner tube mixture are respectively fed into a twin-screw extruder for melt blending, extrusion granulation, to obtain outer tube special material and inner tube special material respectively; S3: The outer tube special material and the inner tube special material are respectively fed into the two hoppers of the double-layer co-extrusion extruder, and after double-layer co-extrusion, die-head compounding, die extrusion, vacuum sizing and cooling, traction and cutting, corrosion-resistant MPP power cable protection pipe is obtained.
[0020] In this invention, in step S1, the mixing speed is preferably 800~1200 rpm, more preferably 1200 rpm; the mixing temperature is preferably 80~100℃, more preferably 90℃; and the mixing time is preferably 8~15 min, more preferably 12 min.
[0021] In this invention, in step S2, the extrusion temperature is preferably 190~230℃, and the screw rotation speed is preferably 200~400rpm.
[0022] In this invention, in step S3, the dual-layer co-extrusion extruder includes an outer tube extruder, an inner tube extruder, and a co-extrusion die; the temperature of the outer tube extruder is preferably 180~220℃; the temperature of the inner tube extruder is preferably 190~230℃; the temperature of the co-extrusion die is preferably 200-225℃; the screw length-to-diameter ratio of the dual-layer co-extrusion extruder is preferably 32~40:1; the vacuum degree of the vacuum sizing cooling is preferably -0.08~-0.04MPa, more preferably -0.06MPa; the temperature of the vacuum sizing cooling is preferably 20~40℃, more preferably 30℃.
[0023] The present invention also provides the application of the above-mentioned corrosion-resistant MPP power cable protection pipe in power cable laying.
[0024] This invention introduces fluororubber into the outer pipe layer formulation. Fluororubber has excellent chemical stability and corrosion resistance, and can effectively resist the erosion of acidic and alkaline soils and chemicals. By enhancing the interfacial bonding force between the filler and the polymer matrix through compatibilizers, the pipe's resistance to media permeation is further improved.
[0025] This invention employs a double-layer composite structure design. The inner and outer layers use the same random copolymer polypropylene and homopolymer polypropylene, ensuring compatibility between the two layers. The outer tube layer is primarily composed of random copolymer polypropylene, homopolymer polypropylene, and fluororubber, giving the tube excellent weather resistance and corrosion resistance. The addition of a compatibilizer significantly improves the tube's impact toughness, solving the problem of traditional MPP tubes struggling to balance strength and toughness. Example data demonstrates that the MPP power cable protection tube provided by this invention has a ring stiffness ≥26kN / m. 2It has a tensile strength ≥30 MPa, elongation at break ≥150%, Vicat softening temperature ≥155℃, and significantly improved acid and alkali corrosion resistance. It can withstand 720 hours of salt spray without corrosion, overcoming the technical contradiction that traditional MPP pipes cannot balance strength, toughness and corrosion resistance.
[0026] The inner tube layer has excellent heat resistance properties, which enables it to maintain good thermal stability when in long-term contact with heating cables, effectively preventing the tube from softening and deforming due to heat accumulation. At the same time, the high thermal resistance inner layer structure also acts as a heat insulation barrier, preventing the heat generated by the cable from being conducted to the external corrosion-resistant layer, and avoiding thermal aging and degradation of the outer tube layer due to long-term exposure to high-temperature environments. This significantly improves the overall service life of the MPP power cable protection pipe under complex working conditions.
[0027] This invention also provides a method for preparing the aforementioned corrosion-resistant MPP power cable protection pipe. This invention employs a double-layer co-extrusion integral molding process, where the inner and outer pipe layers are bonded together in a molten state through a co-extrusion die to form a tightly integrated structure. This avoids the risk of delamination in traditional composite pipes and improves the overall reliability of the pipe.
[0028] The preparation method of the present invention adopts the existing twin-screw granulation and double-layer co-extrusion process, without the need for additional compounding process, and the production process is stable and controllable, making it suitable for large-scale industrial production.
[0029] This invention also provides the application of the above-mentioned corrosion-resistant MPP power cable protection pipe in power cable laying. The MPP power cable protection pipe provided by this invention has corrosion resistance, excellent mechanical properties and long service life, and can be used in power cable laying in complex situations such as underwater areas, acidic and alkaline soils, and trenchless laying. Attached Figure Description
[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0031] Figure 1 Comparative graphs showing the acid resistance tests of the MPP power cable protection pipes prepared in Examples 1-5 and Comparative Examples 1-3; Figure 2 Comparative graphs show the alkali resistance test results of the MPP power cable protection pipes prepared in Examples 1-5 and Comparative Examples 1-3. Detailed Implementation
[0032] To further illustrate the present invention, the following detailed description of the invention's solutions, in conjunction with the accompanying drawings and embodiments, is provided, but should not be construed as limiting the scope of protection of the present invention.
[0033] Example 1 This embodiment provides a corrosion-resistant MPP power cable protection pipe, comprising an inner tube layer and an outer tube layer. By mass fraction, the outer tube layer comprises the following components: Random copolymer polypropylene (ethylene content 2.5%) 60 parts; Homopolymer polypropylene (melt index 2.5 g / 10 min) 20 parts; 10 parts of vinylidene fluoride-hexafluoropropylene copolymer (Mounney viscosity 50, Mw=120000); 3 parts of KH570 modified nano silica; Six parts of nano-calcium carbonate; 5 parts of maleic anhydride-grafted polypropylene; Antioxidant 1010 1.5 parts; Antioxidant 626, 1.5 parts; UV-326 1 copy; 3 parts zinc stearate; The inner tube layer comprises the following components by mass parts: Random copolymer polypropylene (ethylene content 2.5%) 55 parts; Homopolymer polypropylene (melt index 2.5 g / 10 min) 40 parts; Two parts of KH570 modified nano-silica; Six parts of nano-calcium carbonate; 8 parts of maleic anhydride-grafted ethylene-octene copolymer; Antioxidant 1010 1 part; Antioxidant 626 1 part; 1.5 parts zinc stearate.
[0034] The preparation of KH570 modified nano-silica includes the following steps: (1) Place nano-silica in a vacuum drying oven and dry at 100°C for 3 hours. Then add it to ethanol and ultrasonically disperse for 30 minutes to form a suspension with a mass concentration of 12%. (2) Add 5% by mass of nano-silica silane coupling agent KH570 to an ethanol / water mixed solvent, adjust the pH to 4 with acetic acid, and hydrolyze for 60 min at room temperature to obtain silane coupling agent hydrolysate; (3) The hydrolysate of silane coupling agent was slowly added dropwise into the nano silica suspension and stirred for 4 hours under a water bath at 60°C. The mixture was then centrifuged at 5000 rpm for 15 minutes, washed 2-3 times with ethanol, and the washed product was vacuum dried at 100°C for 10 hours. The product was then ground and sieved to obtain KH570 modified nano silica.
[0035] This embodiment provides a method for preparing the above-mentioned corrosion-resistant MPP power cable protection pipe, including the following steps: S1: Weigh the raw material components of the outer tube layer and the inner tube layer according to the above proportions, put them into a high-speed mixer and mix them evenly. The mixing temperature is 90℃, the mixing time is 12min, and the speed of the high-speed mixer is 1000rpm to obtain the outer tube mixture and the inner tube mixture respectively. S2: The outer tube mixture and inner tube mixture obtained in S1 are fed into a twin-screw extruder for melt blending, extrusion and granulation. The extrusion temperature is set as follows: Zone 1 190℃, Zone 2 200℃, Zone 3 210℃, Zone 4 220℃, and Die head 210℃. The screw speed is 300 rpm. The outer tube special material and inner tube special material are obtained respectively. S3: The outer tube material and inner tube material obtained in S2 are respectively fed into the two hoppers of the double-layer co-extrusion extruder. The extruder temperature for the outer tube layer is set as follows: Zone 1 185℃, Zone 2 195℃, Zone 3 205℃, Zone 4 210℃. The extruder temperature for the inner tube layer is set as follows: Zone 1 195℃, Zone 2 205℃, Zone 3 215℃, Zone 4 220℃. The co-extrusion die temperature is 215℃. The screw length-to-diameter ratio is 36:1. Through the double-layer co-extrusion process, the outer tube layer and the inner tube layer are compounded in the die and then extruded through the die. After vacuum sizing and cooling (vacuum degree -0.06MPa, cooling water temperature 30℃), traction, and cutting, the MPP power cable protection pipe is obtained.
[0036] Example 2 This embodiment provides a corrosion-resistant MPP power cable protection pipe, including an inner pipe layer and an outer pipe layer. The outer tube layer comprises the following components by mass fraction: Random copolymer polypropylene (ethylene content 2.5%) 50 parts; Homopolymer polypropylene (melt index 2.5 g / 10 min) 20 parts; 12 parts of vinylidene fluoride-hexafluoropropylene copolymer (Mounney viscosity 50, Mw=150000); 5 parts of KH570 modified nano-silica; 10 parts of nano-calcium carbonate; Six parts of maleic anhydride-grafted polypropylene; Antioxidant 1010 1.5 parts; Antioxidant 626, 1.5 parts; UV-329 1 copy; 3 parts zinc stearate; The inner tube layer comprises the following components by mass parts: Random copolymer polypropylene (ethylene content 2.5%) 60 parts; Homopolymer polypropylene (melt index 2.5 g / 10 min) 30 parts; Four parts of KH570 modified nano-silica; 8 parts of nano-calcium carbonate; 6 parts of maleic anhydride-grafted ethylene-octene copolymer; Antioxidant 1010 1 part; Antioxidant 626 1 part; Two parts zinc stearate.
[0037] The preparation of KH570 modified nano-silica includes the following steps: (1) Place nano-silica in a vacuum drying oven and dry at 100°C for 3 hours. Then add it to ethanol and ultrasonically disperse for 30 minutes to form a suspension with a mass concentration of 12%. (2) Add 5% by mass of nano-silica silane coupling agent KH570 to an ethanol / water mixed solvent, adjust the pH to 4 with acetic acid, and hydrolyze for 60 min at room temperature to obtain silane coupling agent hydrolysate; (3) The hydrolysate of silane coupling agent was slowly added dropwise into the nano silica suspension and stirred for 4 hours under a water bath at 60°C. The mixture was then centrifuged at 5000 rpm for 15 minutes, washed 2-3 times with ethanol, and the washed product was vacuum dried at 100°C for 10 hours. The product was then ground and sieved to obtain KH570 modified nano silica.
[0038] This embodiment provides a method for preparing the above-mentioned corrosion-resistant MPP power cable protection pipe, including the following steps: S1: Weigh the raw material components of the outer tube layer and the inner tube layer according to the above proportions, put them into the high-speed mixer and mix them evenly. The mixing temperature is 90℃, the mixing time is 10min, and the speed of the high-speed mixer is 1100rpm. The outer tube mixture and the inner tube mixture are obtained respectively. S2: The outer tube mixture and inner tube mixture obtained in S1 are fed into a twin-screw extruder for melt blending, extrusion and granulation. The extrusion temperature is set as follows: Zone 1 195℃, Zone 2 205℃, Zone 3 215℃, Zone 4 225℃, and Die head 215℃. The screw speed is 350 rpm. The outer tube special material and inner tube special material are obtained respectively. S3: The outer tube material and inner tube material obtained in S2 are respectively fed into the two hoppers of the double-layer co-extrusion extruder. The extruder temperature for the outer tube layer is set as follows: Zone 1 190℃, Zone 2 200℃, Zone 3 210℃, Zone 4 215℃. The extruder temperature for the inner tube layer is set as follows: Zone 1 200℃, Zone 2 210℃, Zone 3 220℃, Zone 4 225℃. The co-extrusion die temperature is 220℃. The screw length-to-diameter ratio is 36:1. Through the double-layer co-extrusion process, the outer tube layer and the inner tube layer are compounded in the die and then extruded through the die. After vacuum sizing and cooling (vacuum degree -0.05MPa, cooling water temperature 25℃), traction, and cutting, the MPP power cable protection pipe is obtained.
[0039] Example 3 This embodiment provides a corrosion-resistant MPP power cable protection pipe, including an inner pipe layer and an outer pipe layer. The outer tube layer comprises the following components by mass fraction: Random copolymer polypropylene (ethylene content 3.0%) 68 parts; 18 parts of homopolymer polypropylene (melt index 1.5 g / 10 min); 9 parts of vinylidene fluoride-hexafluoropropylene copolymer (Mounney viscosity 45, Mw=120000); Four parts of KH570 modified nano-silica; 12 parts of nano-calcium carbonate; 7 parts of maleic anhydride-grafted ethylene-octene copolymer; Antioxidant 1010 1 part; Antioxidant 626, 1.5 parts; UV-928 0.8 copies; 3 parts paraffin; The inner tube layer comprises the following components by mass parts: Random copolymer polypropylene (ethylene content 3.0%) 70 parts; Homopolymer polypropylene (melt index 1.5 g / 10 min) 25 parts; 3 parts of KH570 modified nano silica; 7 parts of nano-calcium carbonate; 7 parts of maleic anhydride-grafted polypropylene; Antioxidant 1010 0.8 parts; Antioxidant 626, 1.2 parts; 2.2 parts of zinc stearate.
[0040] The preparation of KH570 modified nano-silica includes the following steps: (1) Place nano-silica in a vacuum drying oven and dry at 100°C for 3 hours. Then add it to ethanol and ultrasonically disperse for 30 minutes to form a suspension with a mass concentration of 12%. (2) Add 5% by mass of nano-silica silane coupling agent KH570 to an ethanol / water mixed solvent, adjust the pH to 4 with acetic acid, and hydrolyze for 60 min at room temperature to obtain silane coupling agent hydrolysate; (3) The hydrolysate of silane coupling agent was slowly added dropwise into the nano silica suspension and stirred for 4 hours under a water bath at 60°C. The mixture was then centrifuged at 5000 rpm for 15 minutes, washed 2-3 times with ethanol, and the washed product was vacuum dried at 100°C for 10 hours. The product was then ground and sieved to obtain KH570 modified nano silica.
[0041] This embodiment provides a method for preparing the above-mentioned corrosion-resistant MPP power cable protection pipe, including the following steps: S1: Weigh the raw material components of the outer tube layer and the inner tube layer according to the above proportions, put them into the high-speed mixer and mix them evenly. The mixing temperature is 90℃, the mixing time is 15min, and the speed of the high-speed mixer is 900rpm to obtain the outer tube mixture and the inner tube mixture respectively. S2: The outer tube mixture and inner tube mixture obtained in S1 are fed into a twin-screw extruder for melt blending, extrusion and granulation. The extrusion temperature is set as follows: Zone 1 185℃, Zone 2 195℃, Zone 3 205℃, Zone 4 215℃, and Die head 205℃. The screw speed is 250 rpm, and the outer tube special material and inner tube special material are obtained respectively. S3: The outer tube material and inner tube material obtained in S2 are respectively fed into the two hoppers of the double-layer co-extrusion extruder. The extruder temperature for the outer tube layer is set as follows: Zone 1 180℃, Zone 2 190℃, Zone 3 200℃, Zone 4 205℃. The extruder temperature for the inner tube layer is set as follows: Zone 1 190℃, Zone 2 200℃, Zone 3 210℃, Zone 4 215℃. The co-extrusion die temperature is 210℃. The screw length-to-diameter ratio is 36:1. Through the double-layer co-extrusion process, the outer tube layer and the inner tube layer are compounded in the die and then extruded through the die. After vacuum sizing and cooling (vacuum degree -0.07MPa, cooling water temperature 35℃), traction, and cutting, the MPP power cable protection pipe is obtained.
[0042] Example 4 This embodiment provides a corrosion-resistant MPP power cable protection pipe, including an inner pipe layer and an outer pipe layer. The outer tube layer comprises the following components by mass fraction: Random copolymer polypropylene (ethylene content 2.0%) 72 parts; 14 parts of homopolymer polypropylene (melt index 1.5 g / 10 min); 8 parts of vinylidene fluoride-hexafluoropropylene copolymer (Mounney viscosity 55, Mw=180000); 6 parts of KH570 modified nano silica; 14 parts of nano-calcium carbonate; 5 parts of maleic anhydride-grafted polypropylene; Antioxidant 1010 1 part; Antioxidant 626 1 part; UV-326 1.5 copies; 4 parts stearic acid; The inner tube layer comprises the following components by mass parts: Random copolymer polypropylene (ethylene content 2.0%) 80 parts; 15 parts of homopolymer polypropylene (melt index 4.0 g / 10 min); 5 parts of KH570 modified nano-silica; 10 parts of nano-calcium carbonate; 5 parts of maleic anhydride-grafted ethylene-octene copolymer; Antioxidant 1010 1.2 parts; Antioxidant 626, 0.8 parts; 2.5 parts of polypropylene wax.
[0043] The preparation of KH570 modified nano-silica includes the following steps: (1) Place nano-silica in a vacuum drying oven and dry at 100°C for 3 hours. Then add it to ethanol and ultrasonically disperse for 30 minutes to form a suspension with a mass concentration of 12%. (2) Add 5% by mass of nano-silica silane coupling agent KH570 to an ethanol / water mixed solvent, adjust the pH to 4 with acetic acid, and hydrolyze for 60 min at room temperature to obtain silane coupling agent hydrolysate; (3) The hydrolysate of silane coupling agent was slowly added dropwise into the nano silica suspension and stirred for 4 hours under a water bath at 60°C. The mixture was then centrifuged at 5000 rpm for 15 minutes, washed 2-3 times with ethanol, and the washed product was vacuum dried at 100°C for 10 hours. The product was then ground and sieved to obtain KH570 modified nano silica.
[0044] This embodiment provides a method for preparing the above-mentioned corrosion-resistant MPP power cable protection pipe, including the following steps: S1: Weigh the raw material components of the outer tube layer and the inner tube layer according to the above proportions, put them into the high-speed mixer and mix them evenly. The mixing temperature is 90℃, the mixing time is 8min, and the speed of the high-speed mixer is 1200rpm to obtain the outer tube mixture and the inner tube mixture respectively. S2: The outer tube mixture and inner tube mixture obtained in S1 are fed into a twin-screw extruder for melt blending, extrusion and granulation. The extrusion temperature is set as follows: Zone 1 200℃, Zone 2 210℃, Zone 3 220℃, Zone 4 230℃, and Die head 220℃. The screw speed is 400 rpm, and the outer tube special material and inner tube special material are obtained respectively. S3: The outer tube material and inner tube material obtained in S2 are respectively fed into the two hoppers of the double-layer co-extrusion extruder. The extruder temperature of the outer tube layer is set as follows: Zone 1 195℃, Zone 2 205℃, Zone 3 215℃, Zone 4 220℃. The extruder temperature of the inner tube layer is set as follows: Zone 1 205℃, Zone 2 215℃, Zone 3 225℃, Zone 4 230℃. The co-extrusion die temperature is 225℃. The screw length-to-diameter ratio is 36:1. Through the double-layer co-extrusion process, the outer tube layer and the inner tube layer are compounded in the die and then extruded through the die. After vacuum sizing and cooling (vacuum degree -0.08MPa, cooling water temperature 20℃), traction, and cutting, the MPP power cable protection pipe is obtained.
[0045] Example 5 This embodiment provides a corrosion-resistant MPP power cable protection pipe, including an inner pipe layer and an outer pipe layer. The outer tube layer comprises the following components by mass fraction: Random copolymer polypropylene (ethylene content 1.5%) 55 parts; Homopolymer polypropylene (melt index 5.0 g / 10 min) 12 parts; 11 parts of vinylidene fluoride-hexafluoropropylene copolymer (Mounney viscosity 60, Mw=200000); 5.5 parts of KH570 modified nano-silica; 13 parts of nano-calcium carbonate; 7.5 parts of maleic anhydride-grafted ethylene-octene copolymer; Antioxidant 1010 2 parts; Antioxidant 626 1 part; UV-329 1.5 copies; 3 parts stearic acid; The inner tube layer comprises the following components by mass parts: Random copolymer polypropylene (ethylene content 1.5%) 65 parts; 35 parts of homopolymer polypropylene (melt index 50 g / 10 min); 4.5 parts of KH570 modified nano-silica; 9 parts of nano-calcium carbonate; 7 parts of maleic anhydride-grafted polypropylene; Antioxidant 1010 1.5 parts; Antioxidant 626, 0.5 parts; Two parts zinc stearate.
[0046] The preparation of KH570 modified nano-silica includes the following steps: (1) Place nano-silica in a vacuum drying oven and dry at 100°C for 3 hours. Then add it to ethanol and ultrasonically disperse for 30 minutes to form a suspension with a mass concentration of 12%. (2) Add 5% by mass of nano-silica silane coupling agent KH570 to an ethanol / water mixed solvent, adjust the pH to 4 with acetic acid, and hydrolyze for 60 min at room temperature to obtain silane coupling agent hydrolysate; (3) The hydrolysate of silane coupling agent was slowly added dropwise into the nano silica suspension and stirred for 4 hours under a water bath at 60°C. The mixture was then centrifuged at 5000 rpm for 15 minutes, washed 2-3 times with ethanol, and the washed product was vacuum dried at 100°C for 10 hours. The product was then ground and sieved to obtain KH570 modified nano silica.
[0047] This embodiment provides a method for preparing the above-mentioned corrosion-resistant MPP power cable protection pipe, including the following steps: S1: Weigh the raw material components of the outer tube layer and the inner tube layer according to the above proportions, put them into a high-speed mixer and mix them evenly. The mixing temperature is 90℃, the mixing time is 12min, and the speed of the high-speed mixer is 1000rpm to obtain the outer tube mixture and the inner tube mixture respectively. S2: The outer tube mixture and inner tube mixture obtained in S1 are fed into a twin-screw extruder for melt blending, extrusion and granulation. The extrusion temperature is set as follows: Zone 1 190℃, Zone 2 200℃, Zone 3 210℃, Zone 4 220℃, and Die head 210℃. The screw speed is 300 rpm. The outer tube special material and inner tube special material are obtained respectively. S3: The outer tube material and inner tube material obtained in S2 are respectively fed into the two hoppers of the double-layer co-extrusion extruder. The extruder temperature for the outer tube layer is set as follows: Zone 1 185℃, Zone 2 195℃, Zone 3 205℃, Zone 4 210℃. The extruder temperature for the inner tube layer is set as follows: Zone 1 195℃, Zone 2 205℃, Zone 3 215℃, Zone 4 220℃. The co-extrusion die temperature is 215℃. The screw length-to-diameter ratio is 36:1. Through the double-layer co-extrusion process, the outer tube layer and the inner tube layer are compounded in the die and then extruded through the die. After vacuum sizing and cooling (vacuum degree -0.06MPa, cooling water temperature 30℃), traction, and cutting, the MPP power cable protection pipe is obtained.
[0048] Comparative Example 1 Commercially available ordinary MPP power cable protection tubing is used (single-layer structure, without added fluororubber and modified nano fillers).
[0049] Comparative Example 2 This comparative example provides an MPP power cable protection pipe, which has basically the same composition as Example 1, except that no fluororubber is added.
[0050] Comparative Example 3 This comparative example provides an MPP power cable protection pipe, which has basically the same composition as Example 1, except that no fluororubber compatibilizer is added to either the outer or inner pipe layer.
[0051] Performance testing The present invention conducts performance tests on the MPP power cable protection pipes prepared in Examples 1 to 5. The performance test items and standards are shown in Table 1, and the test results are shown in Table 2. The performance tests are also conducted on the MPP power cable protection pipes of Comparative Examples 1 to 3. The performance test items and standards are shown in Table 1, and the test results are shown in Table 3.
[0052] The acid / alkali resistance test comparison charts of the MPP power cable protection pipes prepared in Examples 1-5 and Comparative Examples 1-3 are shown below. Figure 1-2 .
[0053] Table 1 Test Items and Standards
[0054] Table 2 Performance test results of Examples 1-5
[0055] Table 3 Performance test results of Comparative Examples 1-3
[0056] From Tables 2-3 and Figure 1-2 It can be seen that the MPP power cable protection pipes prepared in Examples 1-5 all exhibit excellent comprehensive performance: ring stiffness: 26.2~29.3 kN / m 2 It is far superior to Comparative Example 1 (21.3 kN / m). 2 Among them, Example 5 had the highest ring stiffness; tensile strength: 30.2~33.1 MPa, which is better than Comparative Example 1 (25.6 MPa), and Examples 4 and 5 had higher strength; elongation at break: 152~195%, which is better than Comparative Example 1 (138%), with Example 3 (high compatibilizer) having the highest elongation at break (195%), showing the best toughness; Vicat softening temperature: 155~158℃, which is better than Comparative Example 1 (150℃), meeting the heat resistance requirements of MPP pipes; corrosion resistance: acid / alkali mass change rate of 0.39~0.52%, which is significantly better than Comparative Example 1 (1.18~1.26%), and no corrosion after 720 hours of salt spray.
[0057] Compared to Example 1, Comparative Example 2, without the addition of fluororubber, showed an increase in the rate of change in acid resistance from 0.42% to 1.05% (an increase of 150%); an increase in the rate of change in alkali resistance from 0.38% to 0.98% (an increase of 158%); slight rust spots appeared in the salt spray test; and ring stiffness and tensile strength also decreased. This indicates that the introduction of fluororubber can improve the corrosion resistance of MPP pipes.
[0058] Compared to Example 1, Comparative Example 3, which did not contain a compatibilizer, showed a significant decrease in elongation at break from 185% to 98% (a decrease of 47%), resulting in a marked deterioration in pipe toughness. Ring stiffness and tensile strength also decreased, and corrosion resistance slightly declined. This demonstrates that compatibilizers play an irreplaceable role in improving the interfacial bonding between the filler and the polymer matrix and enhancing pipe toughness.
[0059] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A corrosion resistant MPP electric power cable protection pipe, characterized in that, Includes inner tubular layer and outer tubular layer; The outer tube layer comprises the following components by mass parts: 50-72 parts of random copolymer polypropylene; 14-28 parts of homopolymer polypropylene; 8-12 parts of fluororubber; 3-6 parts of silane coupling agent modified nano-silica; 6-14 parts of nano-calcium carbonate; 5-8 parts compatibilizer; Antioxidant 1-3 parts; 0.5-1.5 parts of UV absorber; 2.5 to 4 parts lubricant; The inner tube layer comprises the following components by mass parts: 55-80 parts of random copolymer polypropylene; 15-40 parts of homopolymer polypropylene; 2-5 parts of silane coupling agent modified nano-silica; 6-10 parts of nano-calcium carbonate; 5-8 parts compatibilizer; 1-2 parts antioxidant; 1-2.5 parts lubricant; In the outer tube layer, the ethylene content of the random copolymer polypropylene is 1% to 4% by mass; the melt index of the homopolymer polypropylene is 0.9 to 6 g / 10 min. In the inner tube layer, the ethylene content of the random copolymer polypropylene is 1% to 4% by mass; the melt index of the homopolymer polypropylene is 0.9 to 6 g / 10 min.
2. The corrosion-resistant MPP power cable protection pipe according to claim 1, characterized in that, The fluororubber is a copolymer of vinylidene fluoride and hexafluoropropylene; the Mooney viscosity of the fluororubber is 40-60, and the weight-average molecular weight is 100,000-200,000.
3. The corrosion-resistant MPP power cable protection pipe according to claim 1, characterized in that, In the outer tube layer, the antioxidants include antioxidant 1010 and antioxidant 626; the mass ratio of antioxidant 1010 to antioxidant 626 is 1:1~1.
5. In the inner tube layer, the antioxidants include antioxidant 1010 and antioxidant 626; the mass ratio of antioxidant 1010 to antioxidant 626 is 1:1~1.
5.
4. The corrosion-resistant MPP power cable protection pipe according to claim 1, characterized in that, The UV absorber is one of UV-326, UV-329, and UV-928.
5. The corrosion-resistant MPP power cable protection pipe according to claim 1, characterized in that, In the outer tube layer, the compatibilizer is one of maleic anhydride-grafted polypropylene and maleic anhydride-grafted ethylene-octene copolymer. In the inner tube layer, the compatibilizer is one of maleic anhydride-grafted polypropylene or maleic anhydride-grafted ethylene-octene copolymer.
6. The corrosion-resistant MPP power cable protection pipe according to claim 1, characterized in that, In the outer tube layer, the lubricant is one of polypropylene wax, paraffin wax, stearic acid, and zinc stearate; In the inner tube layer, the lubricant is one of polypropylene wax, paraffin wax, stearic acid, or zinc fatty acid.
7. A method for preparing the corrosion-resistant MPP power cable protection pipe according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1: Weigh the raw material components of the outer tube layer and the inner tube layer according to the proportion, and put them into the high-speed mixer to mix evenly to obtain the outer tube mixture and the inner tube mixture. S2: The outer tube mixture and the inner tube mixture are respectively fed into a twin-screw extruder for melt blending, extrusion granulation, to obtain outer tube special material and inner tube special material respectively; S3: The outer tube special material and the inner tube special material are respectively fed into the two hoppers of the double-layer co-extrusion extruder, and after double-layer co-extrusion, die-head compounding, die extrusion, vacuum sizing and cooling, traction and cutting, corrosion-resistant MPP power cable protection pipe is obtained.
8. The method for preparing the corrosion-resistant MPP power cable protection pipe according to claim 7, characterized in that, In step S2, the extrusion temperature is 190~230℃ and the screw speed is 200~400rpm.
9. The method for preparing the corrosion-resistant MPP power cable protection pipe according to claim 7, characterized in that, In step S3, the screw length-to-diameter ratio of the double-layer co-extrusion extruder is 32~40:
1.
10. The application of the corrosion-resistant MPP power cable protection pipe according to any one of claims 1 to 6 or the corrosion-resistant MPP power cable protection pipe prepared by the preparation method according to any one of claims 7 to 9 in the laying of power cables.