A heat-resistant high-strength MPP power cable sheath and its preparation method

Abstract

The present invention provides a heat-resistant high-strength MPP power cable sheath pipe and a preparation method thereof, comprising a mounting seat, a mounting channel movably connected to one side of the mounting seat, and a support plate fixedly connected inside the mounting channel. The heat-resistant high-strength MPP power cable sheath pipe and a preparation method thereof, by increasing the proportion of internal elastic parts, the sheath sleeve does not change with temperature changes; it has good wear resistance and resistance to environmental stress cracking, increases the toughness of the sheath pipe, reduces the generation of burrs after injection molding, and the problem of easy deformation just after molding, and then uses an adjustable structure to chamfer and smooth the periphery of the pipe, thereby improving the accuracy of the pipe, and through the angle adjustment structure, the thickness of the pipe can be stably fitted at right angles, and then polished, so that the polishing range of the pipe is large, and both ends of the pipe can be polished, and through the magnetic setting, the internal heat dissipation structure of the pipe is stably fixed to the inside of the pipe, which has a good effect on the timely cooling of the pipe.

Description

Technical Field

[0001] The present invention relates to the field of polymer compositions, in particular to a heat-resistant high-strength MPP power cable sheath pipe and a preparation method thereof. Background Art

[0002] MPP power pipes have excellent performance in electrical insulation and corrosion resistance. They are not only highly reliable, but also able to operate stably for a long time in different environments. They are made of modified polypropylene as the main raw material. Modified polypropylene trenchless pipes are widely used as protective pipes for power cables and communication cables. As a trenchless jacking construction, its product personality is more prominent. It meets the development requirements of modern cities. The connection of MPP power pipes is done by hot-melt welding with a welding machine. The welding point temperature is controlled at around 200 degrees. When this temperature is reached, the two ends can be butt-jointed. After the MMP power pipe is produced by thermoplastic machinery, it is easy to have uneven problems at the end, resulting in unstable connection of the power pipe.

[0003] Regarding the above-mentioned heat-resistant high-strength MPP power cable sheath pipe and its preparation method, a search found that there is a patent number CN202110857133.0 of a high-strength insulated MPP power cable pipe and its preparation method. The high-strength insulated MPP power cable pipe contains the following components by weight: 75-85 parts of isotactic polypropylene resin, 6-10 parts of elastomer rubber type CPE, 7-9 parts of block copolymer polypropylene, 24-26 parts of ultra-high molecular weight polyethylene resin, 3-5 parts of flame retardant fuel, plasticizer 8-12 parts of an agent, 1-3 parts of an antioxidant, 1-4 parts of a light stabilizer, and 2-5 parts of a mixed auxiliary material; the cable tube body is prepared by the following steps: step 1, weighing isotactic polypropylene resin, elastomeric rubber type CPE, block copolymer polypropylene, ultra-high molecular weight polyethylene resin, flame retardant, plasticizer, antioxidant, light stabilizer, and mixed auxiliary materials according to weight proportions; the cable tube body prepared by the present invention has excellent insulation and high strength, ensuring that it has good wear resistance and a longer service life when used;

[0004] When the heat-resistant and high-strength MPP power cable sheath is polished, the cross-section of the sheath is polished by a wiping machine. When the sheath has a certain thickness, the wiping machine has a small polishing range for the MPP power cable sheath, and the thickness of the sheath cannot be thoroughly polished inside and outside, resulting in poor docking accuracy of the sheath in the later stage. At the same time, before the MPP power cable sheath is cut off, the material is heated and then injection-molded and extruded to produce the sheath. The temperature of the sheath is relatively high, and direct cutting can easily cause surface deformation of the sheath due to the soft surface material of the sheath. Summary of the Invention

[0005] The purpose of the present invention is to provide a heat-resistant and high-strength MPP power cable sheath pipe and a preparation method thereof.

[0006] To achieve the above objectives, the present invention provides the following technical solutions: a heat-resistant high-strength MPP power cable sheath tube and a preparation method thereof, comprising a mounting seat, one side of the mounting seat being movably connected to a mounting channel, and the interior of the mounting channel being fixedly connected to a support plate.

[0007] As a further solution of the present invention: one side of the mounting channel is fixedly connected to a polishing box, the inner bottom of the polishing box is movably connected to a gear, the top of the gear is movably connected to an outer ring, the outer ring is fixedly connected to tooth blocks around, the outer ring is movably connected to a limiting ring inside the limiting ring, the inner ring is movably connected to a connecting piece around the inner ring, the inner ring is fixedly connected to a mounting rod, the top of the mounting rod is fixedly connected to a fixed seat, one side of the fixed seat is movably connected to a movable plate, the top of the fixed seat is fixedly connected to a second polishing block, the fixed seat is movably connected to a slider, one side of the slider is fixedly connected to a spring, the top of the slider is fixedly connected to a clamping plate, one side of the movable plate is fixedly connected to the first polishing block, and the other side of the movable plate is fixedly connected to the third polishing block.

[0008] As a further solution of the present invention: the interior of the polishing box is hollow, a motor is fixedly installed on one side of the polishing box, an output end of the motor is connected to a gear, and the gear is meshed with a gear block.

[0009] As a further solution of the present invention: a through groove is provided inside the limiting ring, the outer ring drives the inner ring to rotate in the through groove through a connecting piece, and a plurality of the fixing seats are equidistantly distributed on the inner wall of the inner ring through the mounting rod.

[0010] As a further solution of the present invention: the fixed seat is rotatably connected to the movable plate through a reset spring, the movable plate and the fixed seat are set at an angle of 90°-180°, and the top of the first grinding block is tilted to one side.

[0011] As a further solution of the present invention: a slide groove is provided inside the fixing seat, and the card plate is slid from one end to the other end inside the slide groove through a slider, and the card plate is in conflict with the top of the first grinding block. The card plate is made of silicone material, one end of the card plate is tilted downward, and a protrusion is provided on the top of the card plate.

[0012] As a further solution of the present invention: the bottom of the support plate is fixedly connected to a bracket, one side of the support plate is fixedly connected to an external cooling pipe, the bottom of the external cooling pipe is fixedly connected to an air duct, the inner wall of the external cooling pipe is fixedly installed with an electromagnet, the interior of the external cooling pipe is movably connected to the inner cooling pipe, the outer surface of the inner cooling pipe is fixedly connected to a spring clip, the top of the spring clip is fixedly connected to a magnetic block, a fan is fixedly installed on one side of the inner cooling pipe, the other side of the inner cooling pipe is fixedly connected to a wind bowl, the middle of the interior of the wind bowl is fixedly connected to an air outlet, and the inner wall of the wind bowl is fixedly connected to an air guide vane.

[0013] As a further solution of the present invention: an air outlet is provided inside the support plate, the air outlet is communicated with an external cooling pipe, and the external cooling pipe is connected to an air outlet port of an air cooler.

[0014] As a further solution of the present invention: the interior of the inner cooling pipe is a hollow structure, the inner cooling pipe is connected to the air outlet, and the air outlet is provided with air holes around it.

[0015] As a further solution of the present invention: one side of the air guide plate is tilted downward, and the air guide plate is arranged counterclockwise around the air outlet.

[0016] As a further solution of the present invention: the positions of the magnetic block and the electromagnet correspond to each other, the magnetic block and the electromagnet are magnetically attracted to each other, and the spring piece is arranged in a "Z" shape.

[0017] A heat-resistant high-strength MPP power cable sheath and a preparation method thereof, comprising the following steps:

[0018] S01: Weigh equal proportions of materials to prepare 70-80 parts of polypropylene, 1-3 parts of compatibilizer, 2-5 parts of antioxidant, 15-20 parts of chlorinated polyethylene, 10-12 parts of nitrile rubber, 4-6 parts of flame retardant, 1-4 parts of light stabilizer, 3-5 parts of flame retardant, and 7-10 parts of silane crosslinking agent and crosslinking agent;

[0019] S02: Mix the above solvents according to the formula ratio at a temperature of 100°-120°, stir for 30 minutes, and extrude and granulate to prepare a modified material;

[0020] S03: The hot press and hot injection machine are heated, and the hot press starts extrusion. The barrel temperature is: 190℃ for the first stage, 220℃ for the second stage, and 210℃ for the third stage; the screw aspect ratio is 25:1; the screw speed is 130-170r / min;

[0021] S04: The finished pipe enters the push pipe and moves forward. When the finished pipe enters the external cooling pipe, it is cooled in time by the cold air generated by the external cooling pipe.

[0022] S05: The inner cooling pipe is connected to the outer cooling pipe, and the inner cooling pipe blows cold air inward to cool the inside of the pipe;

[0023] S06: When the sheath tube moves forward, the fixing seat rotates, and the sheath tube contacts the first grinding block to grind the sheath tube.

[0024] Beneficial effects

[0025] 1. The present invention provides a heat-resistant, high-strength MPP power cable sheath pipe and a preparation method thereof. By increasing the proportion of internal elastic parts, the sheath of the sheath does not change with temperature; it has good wear resistance and resistance to environmental stress cracking, which increases the toughness of the sheath pipe, reduces the generation of burrs after injection molding, and the problem of easy deformation just after molding. The pipe periphery is chamfered and smoothed through an adjustable structure, thereby improving the accuracy of the pipe.

[0026] 2. The present invention provides a heat-resistant and high-strength MPP power cable sheath pipe and a preparation method thereof. The movable plate and the fixed seat are arranged at an angle of 90°-180°. The top of the first grinding block is tilted to one side, and the connecting block passes through the interior of the sound-absorbing cotton and is disassembled and arranged with the second fixing piece. The upper sides of the connecting block are concave inward, and slide grooves are provided on both sides of the concave connecting block. Through the angle adjustment structure, the thickness of the pipe can be stably fitted at a right angle, and then polished, so that the polishing range of the pipe is large, and both ends of the pipe can be polished.

[0027] 3. The present invention provides a heat-resistant, high-strength MPP power cable sheath pipe and a preparation method thereof. By aligning the positions of the magnetic block and the electromagnet, the magnetic block and the electromagnet are magnetically attracted to each other, one side of the air guide plate is tilted downward, and the air guide plate is arranged counterclockwise around the air outlet, which can discharge wind from the interior of the pipe and cool the inside and outside of the pipe at the same time. Through the magnetic setting, the internal heat dissipation structure of the pipe is stably fixed to the inside of the pipe, which has a good effect on the timely cooling of the pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is an overall structural diagram of the sleeve manufacturing device of the present invention.

[0029] Figure 2 This is an overall structural diagram of the mounting seat device of the present invention.

[0030] Figure 3 It is the overall structural diagram of the support plate of the present invention.

[0031] Figure 4 This is the overall structural diagram of the outer ring of the present invention.

[0032] Figure 5 This is a structural diagram of the outer ring splitting of the present invention.

[0033] Figure 6 This is the overall structural diagram of the fixing seat of the present invention.

[0034] Figure 7 This is a structural diagram of the fixing seat of the present invention in a deformed state.

[0035] Figure 8 This is a disassembled structural diagram of the fixing seat of the present invention.

[0036] Figure 9 This is the overall structural diagram of the external cooling tube of the present invention.

[0037] Figure 10 This is a structural diagram of the back of the inner cooling tube of the present invention.

[0038] Figure 1-10 : 1. Mounting seat; 101. Hot press; 102. Hot injection machine; 103. Push tube; 104. Operating table; 2. Mounting channel; 201. Grinding box; 202. Outer ring; 203. Gear block; 204. Gear; 205. Limiting ring; 206. Inner ring; 207. Connector; 208. Mounting rod; 209. Fixed seat; 210. Movable plate; 211. First grinding block; 212. Second grinding block; 213. Third grinding block; 214. Clamping plate; 215. Slider; 216. Spring; 3. Support plate; 301. Bracket; 302. External cooling pipe; 303. Air duct; 304. Electromagnet; 305. Internal cooling pipe; 306. Shrapnel; 307. Magnetic block; 308. Wind bowl; 309. Air outlet; 310. Air guide vane; 311. Fan. DETAILED DESCRIPTION

[0039] See also Figure 1-10 In the embodiment of the present invention,

[0040] Example 1: A heat-resistant high-strength MPP power cable sheath tube and a preparation method thereof, comprising a mounting seat 1, a mounting channel 2 movably connected to one side of the mounting seat 1, and a support plate 3 fixedly connected to the interior of the mounting channel 2.

[0041] A grinding box 201 is fixedly connected to one side of the mounting channel 2, a gear 204 is movably connected to the lower part of the grinding box 201, an outer ring 202 is movably connected to the top of the gear 204, a tooth block 203 is fixedly connected to the periphery of the outer ring 202, a limit ring 205 is movably connected to the inner ring 206 inside the limit ring 205, a connector 207 is fixedly connected to the periphery of the inner ring 206, a mounting rod 208 is fixedly connected to the inner ring 206, and the mounting rod 208 is fixedly connected to the inner ring 206. 8 is fixedly connected to the top of the fixed seat 209, and a movable plate 210 is movably connected to one side of the fixed seat 209. A second grinding block 212 is fixedly connected to the top of the fixed seat 209. A slider 215 is movably connected inside the fixed seat 209. A spring 216 is fixedly connected to one side of the slider 215. A clamping plate 214 is fixedly connected to the top of the slider 215. A first grinding block 211 is fixedly connected to one side of the movable plate 210, and a third grinding block 213 is fixedly connected to the other side of the movable plate 210.

[0042] The interior of the polishing box 201 is hollow, and a motor is fixedly installed on one side of the polishing box 201. The output end of the motor is connected to the gear 204, and the gear 204 is meshed with the gear block 203;

[0043] The inner portion of the limiting ring 205 is provided with a through groove, and the outer ring 202 drives the inner ring 206 to rotate in the through groove through the connecting piece 207. A plurality of fixing seats 209 are evenly distributed on the inner wall of the inner ring 206 through the mounting rod 208;

[0044] The fixed seat 209 is rotatably connected to the movable plate 210 via a return spring. The movable plate 210 and the fixed seat 209 are arranged at an angle of 90°-180°. The top of the first grinding block 211 is tilted to one side.

[0045] A slide groove is provided inside the fixing seat 209. A clamping plate 214 is slidably provided from one end to the other end of the slide groove via a slider 215. The clamping plate 214 contacts the top of the first grinding block 211. The clamping plate 214 is made of silicone material. One end of the clamping plate 214 is tilted downward, and a protrusion is provided on the top of the clamping plate 214.

[0046] Among them, when the sheath tube moves, one end of the sheath tube moves toward the inside of the outer ring 202, and the thickness of the sheath tube contacts the first grinding block 211. When the motor is started, the outer ring 202 is released from rotation by the tooth block 203 and the gear 204, driving the inner ring 206 to rotate, so that the fixed seat 209 rotates the outer ring of the sheath tube, and the first grinding block 211 and the second grinding block 212 grind the sheath tube. When the grinding is completed, the sheath tube continues to push forward, driving the clamping plate 214 to move to the movable plate 210, so that the movable plate 210 is parallel to the fixed seat 209. When the sheath tube moves forward all the time, the tip is separated from the movable plate 210, and the movable plate 210 rebounds through the reset spring and is perpendicular to the fixed seat 209. The third grinding block 213 contacts the tail of the sheath tube and rotates for grinding.

[0047] See also Figure 8-10 ,

[0048] Example 2: The difference between Example 2 and Example 1 is that the support plate 3 is located above the mounting channel 2.

[0049] The bottom of the support plate 3 is fixedly connected to a bracket 301, one side of the support plate 3 is fixedly connected to an external cooling pipe 302, the bottom of the external cooling pipe 302 is fixedly connected to an air duct 303, an electromagnet 304 is fixedly installed on the inner wall of the external cooling pipe 302, the inner surface of the external cooling pipe 305 is movably connected to an inner cooling pipe 305, an elastic piece 306 is fixedly connected to the outer surface of the inner cooling pipe 305, the top of the elastic piece 306 is fixedly connected to a magnetic block 307, a fan 311 is fixedly installed on one side of the inner cooling pipe 305, and the other side of the inner cooling pipe 305 is fixedly connected to a wind bowl 308, an air outlet 309 is fixedly connected to the middle of the wind bowl 308, and an air guide vane 310 is fixedly connected to the inner wall of the wind bowl 308;

[0050] An air outlet is provided inside the support plate 3, which is connected to the external cooling pipe 302, and the external cooling pipe 302 is connected to the air outlet port of the air cooler;

[0051] The interior of the inner cooling pipe 305 is a hollow structure, and the inner cooling pipe 305 is connected to the air outlet 309, and the air outlet 309 is provided with air holes around it;

[0052] One side of the air guide plate 310 is tilted downward, and the air guide plate 310 is arranged counterclockwise around the air outlet 309;

[0053] The position of the magnetic block 307 corresponds to that of the electromagnet 304. The magnetic block 307 and the electromagnet 304 are magnetically attracted to each other. The spring piece 306 is arranged in a "Z" shape.

[0054] Among them, through the movement of the sheath tube, the inner cooling tube 305 enters the interior of the sheath tube, and the electromagnet 304 is turned on, so that the magnetic block 307 and the electromagnet 304 are magnetically adsorbed through the sheath tube, and the spring 306 is deformed according to the diameter of the sheath tube. When cooling is required, the fan 311 is started to discharge the flowing air from the air outlet 309, and the inside of the sheath tube is cooled by the guidance of the air guide plate 310.

[0055] See also Figure 1-2 ,

[0056] Example 3: The difference between Example 3 and Example 2 is that the mounting seat 1 is located on the right side of the mounting channel 2;

[0057] A hot press 101 is fixedly mounted on the top of the mounting base 1, a hot injection machine 102 is fixedly connected to one side of the hot press 101, a push tube 103 is fixedly connected to one side of the hot injection machine 102, and an operating table 104 is fixedly connected to the outer surface of the mounting base 1;

[0058] The interior of the hot press 101 extends to the interior of the hot injection machine 102, and the interior of the hot injection machine 102 is slidably arranged from the inside to the outside;

[0059] The interior of the push tube 103 is connected to the hot injection machine 102 , and a material box is provided on the top of the hot injection machine 102 .

[0060] See also Figure 1-10 ,

[0061] A heat-resistant high-strength MPP power cable sheath and a preparation method thereof, comprising the following steps:

[0062] S01: Weigh equal proportions of materials to prepare 70-80 parts of polypropylene, 1-3 parts of compatibilizer, 2-5 parts of antioxidant, 15-20 parts of chlorinated polyethylene, 10-12 parts of nitrile rubber, 4-6 parts of flame retardant, 1-4 parts of light stabilizer, 3-5 parts of flame retardant, and 7-10 parts of silane crosslinking agent and crosslinking agent;

[0063] S02: Mix the above solvents according to the formula ratio at a temperature of 100°-120°, stir for 30 minutes, and extrude and granulate to prepare a modified material;

[0064] S03: The hot press 101 and the hot injection machine 102 are heated, and the hot press 101 starts extrusion. The barrel temperature is: 190°C for the first stage, 220°C for the second stage, and 210°C for the third stage; the screw aspect ratio is 25:1; and the screw speed is 130-170 r / min.

[0065] S04: The finished pipe enters the push pipe 103 and moves forward. When the finished pipe enters the outer cooling pipe 302, it is cooled in time by the cold air generated by the outer cooling pipe 302.

[0066] S05: The inner cooling pipe 305 is connected to the outer cooling pipe 302, and the inner cooling pipe 305 blows cold air inward to cool the inside of the pipe;

[0067] S06: When the sheath tube moves forward, the fixing seat 209 rotates, and the sheath tube contacts the first grinding block 211 to grind the sheath tube.

[0068] The above are only preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention. These should also be regarded as the scope of protection of the present invention. These will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. A heat-resistant and high-strength MPP power cable sheath preparation device, characterized in that , including the mounting base (1): One side of the mounting seat (1) is movably connected to a mounting path (2), and the interior of the mounting path (2) is fixedly connected to a support plate (3); The mounting path (2) is recessed downward, and the mounting path (2) includes: a grinding box (201), an outer ring (202), a tooth block (203), a gear (204), a limiting ring (205), an inner ring (206), a connecting piece (207), a mounting rod (208), a fixing seat (209), a movable plate (210), a first grinding block (211), a second grinding block (212), a third grinding block (213), a clamping plate (214), a slider (215) and a spring (216); One side of the mounting path (2) is fixedly connected to a polishing box (201), the interior of the polishing box (201) is movably connected to a gear (204), the top of the gear (204) is movably connected to an outer ring (202), the outer ring (202) is fixedly connected to a tooth block (203) on all sides, the outer ring (202) is movably connected to a limit ring (205), the limit ring (205) is movably connected to an inner ring (206), the inner ring (206) is fixedly connected to a connecting piece (207) on all sides, the inner ring (206) is fixedly connected to a mounting rod (208), and the mounting rod The top of (208) is fixedly connected to a fixed seat (209), one side of the fixed seat (209) is movably connected to a movable plate (210), the top of the fixed seat (209) is fixedly connected to a second grinding block (212), the interior of the fixed seat (209) is movably connected to a slider (215), one side of the slider (215) is fixedly connected to a spring (216), the top of the slider (215) is fixedly connected to a clamping plate (214), one side of the movable plate (210) is fixedly connected to a first grinding block (211), and the other side of the movable plate (210) is fixedly connected to a third grinding block (213); The interior of the polishing box (201) is hollow, and a motor is fixedly mounted on one side of the polishing box (201), the output end of the motor is connected to a gear (204), and the gear (204) is meshed with a gear block (203); A through groove is provided inside the limiting ring (205), and the outer ring (202) drives the inner ring (206) to rotate in the through groove via a connecting piece (207), and a plurality of fixing seats (209) are equidistantly distributed on the inner wall of the inner ring (206) via a mounting rod (208).

2. The heat-resistant, high-strength MPP power cable sheath preparation device according to claim 1, characterized in that: The fixed seat (209) is rotatably connected to the movable plate (210) via a return spring. The movable plate (210) and the fixed seat (209) are arranged at an angle of 90°-180°. The top end of the first grinding block (211) is tilted to one side.

3. The heat-resistant, high-strength MPP power cable sheath preparation device according to claim 1, characterized in that: A slide groove is provided inside the fixing seat (209), and the card plate (214) is slidably provided from one end to the other end inside the slide groove through a slider (215), and the card plate (214) is in conflict with the top of the first grinding block (211). The card plate (214) is made of silicone material, and one end of the card plate (214) is tilted downward, and a protrusion is provided on the top of the card plate (214).

4. The heat-resistant, high-strength MPP power cable sheath preparation device according to claim 1, characterized in that: The support plate (3) is located above the mounting path (2), and the support plate (3) includes: Bracket (301), external cooling pipe (302), air duct (303), electromagnet (304), internal cooling pipe (305), spring (306), magnetic block (307), wind bowl (308), air outlet (309), air guide (310) and fan (311); The bottom of the support plate (3) is fixedly connected to a bracket (301), one side of the support plate (3) is fixedly connected to an external cooling pipe (302), the bottom of the external cooling pipe (302) is fixedly connected to an air duct (303), the inner wall of the external cooling pipe (302) is fixedly installed with an electromagnet (304), the interior of the external cooling pipe (302) is movably connected to an internal cooling pipe (305), the outer surface of the internal cooling pipe (305) is fixedly connected to a spring (306), the top of the spring (306) is fixedly connected to a magnetic block (307), a fan (311) is fixedly installed on one side of the internal cooling pipe (305), the other side of the internal cooling pipe (305) is fixedly connected to a wind bowl (308), the middle of the interior of the wind bowl (308) is fixedly connected to an air outlet (309), and the inner wall of the wind bowl (308) is fixedly connected to an air guide plate (310).

5. The device for preparing a heat-resistant, high-strength MPP power cable sheath pipe according to claim 4, characterized in that: An air outlet is provided inside the support plate (3), the air outlet is connected to an external cooling pipe (302), and the external cooling pipe (302) is connected to an air outlet port of a cooling fan; The interior of the inner cooling pipe (305) is a hollow structure, the inner cooling pipe (305) is connected to the air outlet (309), and air holes are arranged around the air outlet (309).

6. The device for preparing a heat-resistant, high-strength MPP power cable sheath pipe according to claim 4, characterized in that: One side of the air guide plate (310) is tilted downward, and the air guide plate (310) is arranged counterclockwise around the air outlet (309); The positions of the magnetic block (307) and the electromagnet (304) correspond to each other, the magnetic block (307) and the electromagnet (304) are magnetically attracted to each other, and the spring (306) is arranged in a "Z" shape.

7. A method for preparing a heat-resistant and high-strength MPP power cable sheath according to any one of claims 4 to 6, characterized in that: The following steps are involved: S01: Weigh equal proportions of materials to prepare 70-80 parts of polypropylene, 1-3 parts of compatibilizer, 2-5 parts of antioxidant, 15-20 parts of chlorinated polyethylene, 10-12 parts of nitrile rubber, 4-6 parts of flame retardant, 1-4 parts of light stabilizer, 3-5 parts of flame retardant, and 7-10 parts of silane crosslinking agent and crosslinking agent; S02: The above materials are mixed according to the formula ratio at a temperature of 100 degrees Celsius to 120 degrees Celsius for 30 minutes, and extruded into granules to prepare a modified material; S03: The hot press (101) and the hot injection machine (102) are heated, and the hot press (101) starts extrusion. The barrel temperature is: 190°C for the first stage, 220°C for the second stage, and 210°C for the third stage; the screw aspect ratio is 25:1; and the screw speed is 130-170 r / min; S04: The finished tube enters the push tube (103) and moves forward. When the finished tube enters the outer cooling tube (302), it is promptly cooled by the cold air generated by the outer cooling tube (302); S05: the inner cooling pipe (305) is connected to the outer cooling pipe (302), and the inner cooling pipe (305) blows cold air inward to cool the inside of the pipe; S06: When the sheath tube moves forward, the fixed seat (209) rotates, and the sheath tube contacts the first grinding block (211), thereby grinding the sheath tube.

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