HPVC power cable protection pipe and preparation method thereof

Abstract

The invention discloses an HPVC power cable protection pipe and a preparation method thereof, and relates to the technical field of cable protection pipes. The HPVC power cable protection tube is at least prepared from the following raw materials in parts by weight: 100 parts of high-strength polyvinyl chloride, 35 to 45 parts of epoxy acrylate rubber, 5 to 8 parts of vinyl chloride-g-acrylate copolymer, 8 to 12 parts of epoxidized soybean oil, 3 to 5 parts of calcium-zinc composite stabilizer, 5 to 15 parts of modified hydrotalcite, 0.1 to 0.5 part of beta-diketone, 0.8 to 1.5 parts of calcium stearate and 10 to 20 parts of flame retardant. 12 to 15 parts of modified nano calcium carbonate, 5 to 8 parts of talcum powder, 0.6 to 1.2 parts of antioxidant, 1 to 2 parts of anti-aging agent 4010 and 0.5 to 1.5 parts of ultraviolet light absorber UV531; the modified hydrotalcite is obtained by adding a mixed solution of calcium nitrate and lanthanum nitrate, a sodium hydroxide solution and a sodium bicarbonate solution into a lauryl sodium sulfate solution, mixing and aging, and then carrying out a post-treatment process. The HPVC power cable protection tube prepared by the invention has relatively high strength, good mechanical properties, weather resistance and cold resistance, and long service life.

Description

Technical Field

[0001] The present invention relates to the technical field of cable protection pipes, and particularly relates to an HPVC power cable protection pipe and a preparation method thereof. Background Art

[0002] Polyvinyl chloride (PVC) is one of the general plastic varieties that were developed earlier, have the largest output, and are the most widely used in China. Ordinary polyvinyl chloride soft products have defects such as low mechanical strength, poor heat resistance and cold resistance, and easy migration of plasticizers, which restrict the application of polyvinyl chloride in high-grade products. High-polymerization-degree polyvinyl chloride (HPVC) generally refers to polyvinyl chloride resin with an average polymerization degree greater than 1700. HPVC has a large plasticizer absorption capacity, and its products have greatly improved the mechanical properties, compression set, resilience, heat resistance, cold resistance, etc. of PVC products. HPVC itself is a hard material with an oxygen index of 45 (difficult to burn), but when it is used as cable material, a relatively large amount of plasticizer needs to be added to the polyvinyl chloride resin to achieve the purpose of softness and low temperature resistance. However, the addition of plasticizer will cause a significant decrease in the oxygen index of the polyvinyl chloride material. When an electrical short circuit occurs in the cable and causes the cable to catch fire, the cable is extremely prone to continue burning and generates a large amount of smoke, seriously affecting the rescue work and causing significant property losses. Therefore, it is necessary to improve the flame retardancy, fire prevention and smoke suppression performance of PVC materials; In addition, power cables are often laid in outdoor environments. Due to the increase in the service life of power pipes and the differences in usage environment factors, problems with power pipes are gradually exposed. For example, high temperatures in summer accelerate aging; low temperatures in winter cause changes in the internal metal microstructure of the cable; the soil and plant environment cause corrosion and wear to the outside; the cable has poor weather resistance during use and cracks when used outdoors, which cannot meet the requirements of outdoor use. Therefore, existing PVC casing materials have defects such as insufficient processing performance, low temperature performance, and poor weather resistance, which severely limit the use of this technology. Summary of the Invention

[0003] The purpose of the present invention is to provide an HPVC power cable protection pipe and a preparation method thereof, and solve the following technical problems: Existing HPVC power cable protection pipes have problems of poor flame retardancy and smoke suppression performance, poor processing performance, and insufficient low temperature resistance.

[0004] The purpose of the present invention can be achieved by the following technical solutions: An HPVC power cable protection pipe comprises at least the following raw materials in parts by weight: 100 parts of high-strength polyvinyl chloride, 35 - 45 parts of epoxy acrylate rubber, 5 - 8 parts of vinyl chloride-g-acrylate copolymer, 8 - 12 parts of epoxy soybean oil, 3 - 5 parts of calcium-zinc composite stabilizer, 5 - 15 parts of modified hydrotalcite, 0.1 - 0.5 of β-diketone, 0.8 - 1.5 parts of calcium stearate, 10 - 20 parts of flame retardant, 12 - 15 parts of modified nano calcium carbonate, 5 - 8 parts of talcum powder, 0.6 - 1.2 parts of antioxidant, 1 - 2 parts of antioxidant 4010, 0.5 - 1.5 of ultraviolet absorber UV531; The modified hydrotalcite is calcium-lanthanum hydrotalcite modified by sodium dodecyl sulfate. The modified hydrotalcite is obtained by adding a mixed solution of calcium nitrate and lanthanum nitrate, a sodium hydroxide solution and a sodium bicarbonate solution to a sodium dodecyl sulfate solution, mixing and aging, and then performing a post-treatment process.

[0005] As a further scheme of the present invention: the molar ratio of calcium ions to lanthanum ions in the modified hydrotalcite is 3 - 4:1.

[0006] As a further scheme of the present invention: the concentration of calcium nitrate in the mixed solution is 0.1 - 0.15 mol / L, and the concentration of lanthanum nitrate in the mixed solution is 0.3 - 0.5 mol / L.

[0007] As a further scheme of the present invention: the concentration of the sodium hydroxide solution is 0.8 - 1 mol / L, the concentration of the sodium bicarbonate solution is 0.1 - 0.2 mol / L, and the concentration of the sodium dodecyl sulfate solution is 4 - 5 g / mL.

[0008] As a further scheme of the present invention: the antioxidant is composed of 0.4 - 0.8 parts of antioxidant 1010 and 0.2 - 0.4 parts of antioxidant 168.

[0009] As a further scheme of the present invention: the flame retardant is composed of 12 - 18 parts of ammonium polyphosphate, 3 - 6 parts of pentaerythritol and 2 - 4 parts of zinc borate.

[0010] As a further scheme of the present invention: the modified nano calcium carbonate is obtained by mixing a titanate coupling agent with absolute ethanol, and then mixing with nano calcium carbonate, and reacting through a post-treatment process.

[0011] As a further scheme of the present invention: the mass ratio of nano calcium carbonate to the titanate coupling agent is 100:1 - 2.

[0012] A preparation method of an HPVC power cable protection pipe at least includes the following preparation steps: Add high-strength polyvinyl chloride, calcium-zinc composite stabilizer, modified hydrotalcite, β-diketone, calcium stearate, modified nano calcium carbonate and talc powder into a high-speed mixer for mixing, and then add epoxy acrylate rubber, vinyl chloride-g-acrylate copolymer, epoxy soybean oil, flame retardant, antioxidant, antiozonant 4010 and ultraviolet absorber UV531 to continue mixing to obtain a premix. Add the said premix into a twin-screw extruder for extrusion and cooling and shaping to obtain an HPVC power cable protection pipe.

[0013] The beneficial effects of the present invention: The main base materials of the HPVC power cable protection pipe prepared in the present invention are high-strength polyvinyl chloride, epoxy acrylate rubber and plasticizer. HPVC itself has high mechanical strength and is resistant to chemical corrosion, and is suitable as a power cable protection sleeve. The added epoxy acrylate rubber can improve the toughness of HPVC, especially the low-temperature brittleness, and also improve the weather resistance of the HPVC power cable protection pipe. In addition, calcium-zinc composite stabilizer, modified hydrotalcite, B-diketone, calcium stearate, flame retardant, modified nano calcium carbonate, talc powder, antioxidant, antiozonant 4010 and ultraviolet absorber UV531 are also added to improve the comprehensive performance of the material. The HPVC power cable protection pipe obtained by the present invention has high strength, good mechanical properties, and has both weather resistance and cold resistance, can be used in saline-alkali areas and cold regions, effectively ensures the operation reliability of the cable line, and has great economic and social benefits and broad application prospects.

[0014] In the present invention, the epoxy acrylate rubber added to the high-strength polyvinyl chloride base material is partially crosslinked with HPVC through epoxy groups to form an interpenetrating network structure, making the material have both high toughness and impact resistance, and the low-temperature embrittlement temperature can be reduced to below -40°C. In addition, HPVC itself is resistant to acid, alkali and salt corrosion, and the epoxy acrylate rubber further reduces environmental penetration and improves the weather resistance of the composite material, prolonging the service life of the protection sleeve in harsh environments. The present invention also selects vinyl chloride-g-acrylate copolymer as the compatibilizer for epoxy acrylate rubber and high-strength polyvinyl chloride. In its molecular chain, it contains both polyvinyl chloride structural units, which can be fully embedded in the long chain segments of high-molecular-weight polyvinyl chloride, and acrylate structures, which are similar to the main monomer structure of acrylate rubber and have excellent compatibility. Therefore, vinyl chloride-g-acrylate copolymer can play a bridging role, combining plastic and rubber together to achieve a good interfacial adhesion effect, thereby improving the mechanical properties of the composite material.

[0015] The HPVC power cable protection pipe of the present invention also adds modified hydrotalcite, and the modified hydrotalcite is calcium-lanthanum hydrotalcite modified by a surface modifier. The modified hydrotalcite added in the present invention can serve as an auxiliary heat stabilizer and produce a synergistic effect with the heat stabilizer calcium-zinc composite stabilizer to improve the heat stability. The calcium-zinc composite stabilizer reacts with HCl generated by the decomposition of PVC through calcium stearate and zinc stearate to generate calcium chloride / zinc chloride, inhibiting the autocatalytic degradation reaction of HCl. As a layered double hydroxide, the calcium-lanthanum hydrotalcite can adsorb HCl through its interlayer hydroxyl groups and anions and fix chloride ions through ion exchange. At the same time, the Lewis acidity of lanthanum ions can catalyze the neutralization reaction of HCl, realizing dual-path HCl capture. Moreover, the layered structure of the hydrotalcite can serve as a physical barrier to inhibit the diffusion of degradation products, greatly improving the heat stability of the HPVC power cable protection pipe and improving the processing performance. In the present invention, the flame retardant is ammonium polyphosphate, pentaerythritol, and zinc borate. The modified hydrotalcite can also produce a synergistic flame retardant effect. The calcium oxide and lanthanum oxide decomposed by the hydrotalcite can be embedded in the expanded porous carbon layer formed by ammonium polyphosphate and pentaerythritol, improving the density and high-temperature resistance of the elastic layer. Moreover, the hydrotalcite can adsorb HCl, reducing toxic smoke. After being modified by a surfactant, the hydrotalcite can also release more CO2 to prevent the combustion of polyvinyl chloride (PVC) and enhance the flame retardant and smoke suppression performance. In the present invention, a surfactant is also added to modify the calcium-lanthanum hydrotalcite, which can improve the dispersibility of the hydrotalcite in polyvinyl chloride and improve the fluidity of the hydrotalcite in polyvinyl chloride, thereby enabling polyvinyl chloride to have good mechanical properties.

[0016] The present invention also adds modified nano-calcium carbonate and hydrotalcite. The compounding of calcium carbonate and talc powder is beneficial to improving the impact strength, flexural strength, flexural modulus, and dimensional stability of the material. The compound filling of modified nano-calcium carbonate and talc powder fills the voids between the matrixes, forming entanglement points between the matrix surface and the filler. The entanglement points help to improve the interfacial adhesion force, and the notched impact strength increases. Nano-calcium carbonate improves the impact strength of the HPVC power cable protection pipe, and talc powder improves the strength of the HPVC power cable protection pipe. The two work together to achieve "the combination of rigidity and flexibility". Moreover, through the surface modification of nano-calcium carbonate with a titanate coupling agent, the titanate reduces the interfacial friction between the filler and PVC, and the talc powder flakes play a lubricating role, improving the processing performance of the HPVC power cable protection pipe. Detailed implementation manners

[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0018] Example 1 The preparation method of the modified hydrotalcite includes the following steps: Dissolve 2 g of sodium dodecyl sulfate in 50 mL of deionized water to obtain a sodium dodecyl sulfate solution. Place it in an 80 °C oil bath and fill it with N2 gas. Then, dropwise add 100 mL of a mixed solution of calcium nitrate with a concentration of 0.3 mol / L and lanthanum nitrate with a concentration of 0.1 mol / L, 100 mL of a sodium bicarbonate solution with a concentration of 0.1 mol / L, and 100 mL of a sodium hydroxide solution with a concentration of 0.9 mol / L into the sodium dodecyl sulfate solution through a dropping funnel. Control the dropping rate of the funnel at 1 drop per second, monitor the pH, and always keep the pH of the suspension between 8 and 10. Immediately stop dropping when the pH of the suspension reaches 10. Keep the temperature constant for 4 h. During the constant temperature process, protect it with N2. After the mixed solution ages, transfer it to a hydrothermal reaction kettle and react at 150 °C for 10 h. After the hydrothermal reaction ends, perform suction filtration, wash it with absolute ethanol and high-purity water until it is neutral, and dry it at 70 °C for 12 h to obtain the modified hydrotalcite.

[0019] Example 2 The preparation method of the modified hydrotalcite includes the following steps: Dissolve 2 g of sodium dodecyl sulfate in 50 mL of deionized water to obtain a sodium dodecyl sulfate solution. Place it in an 80 °C oil bath and fill it with N2 gas. Then, dropwise add 100 mL of a mixed solution of calcium nitrate with a concentration of 0.3 mol / L and lanthanum nitrate with a concentration of 0.1 mol / L, 100 mL of a sodium bicarbonate solution with a concentration of 0.2 mol / L, and 100 mL of a sodium hydroxide solution with a concentration of 1 mol / L into the sodium dodecyl sulfate solution through a dropping funnel. Control the dropping rate of the funnel at 1 drop per second, monitor the pH, and always keep the pH of the suspension between 8 and 10. Immediately stop dropping when the pH of the suspension reaches 10. Keep the temperature constant for 4 h. During the constant temperature process, protect it with N2. After the mixed solution ages, transfer it to a hydrothermal reaction kettle and react at 150 °C for 10 h. After the hydrothermal reaction ends, perform suction filtration, wash it with absolute ethanol and high-purity water until it is neutral, and dry it at 70 °C for 12 h to obtain the modified hydrotalcite.

[0020] Example 3 The preparation method of the modified nano calcium carbonate includes the following steps: Place 1.5 g of titanate coupling agent and absolute ethanol in a beaker, stir in a water bath at a constant temperature of 80 °C for 30 min. Then add 100 g of nano calcium carbonate powder and stir and react for 30 min. Perform suction filtration, vacuum dry at 60 °C for 30 min, dry in an oven at 140 °C for 1 h. After drying, wash it alternately with absolute ethanol and high-purity water 3 times, dry it again, and pulverize it to obtain the modified nano calcium carbonate.

[0021] Example 4 The preparation method of a HPVC power cable protection pipe includes the following steps: Add 100 parts by mass of high-strength polyvinyl chloride HD-3000, 4 parts by mass of calcium-zinc composite stabilizer, 10 parts by mass of the modified hydrotalcite obtained in Example 1, 0.3 parts by mass of β-diketone, 1 part by mass of calcium stearate, 12 parts by mass of the modified nano calcium carbonate prepared in Example 3, and 6 parts by mass of talc powder into a high-speed mixer and knead at 160 °C for 8 min. Then add 40 parts by mass of epoxy acrylate rubber, 6 parts by mass of vinyl chloride-g-acrylate copolymer, 10 parts by mass of epoxy soybean oil, 15 parts by mass of ammonium polyphosphate, 5 parts by mass of pentaerythritol, 3 parts by mass of zinc borate, 0.6 parts by mass of antioxidant 1010, 0.3 parts by mass of antioxidant 168, 1 part by mass of antioxidant 4010, and 0.8 parts by mass of ultraviolet absorber UV531 and continue to knead at 140 °C for 10 min to obtain a premix; Add the above-obtained premix into a twin-screw extruder for extrusion. Set the temperature: zone 1 at 150 °C, zone 2 at 160 °C, die at 165 °C, screw speed at 30 rpm, vacuum degree at -0.06 MPa, and cool and shape at room temperature to obtain the HPVC power cable protection tube composition.

[0022] Example 5 A method for preparing an HPVC power cable protection tube includes the following steps: Add 100 parts by mass of high-strength polyvinyl chloride HD-3000, 4 parts by mass of calcium-zinc composite stabilizer, 10 parts by mass of the modified hydrotalcite obtained in Example 2, 0.3 parts by mass of β-diketone, 1 part by mass of calcium stearate, 12 parts by mass of the modified nano calcium carbonate prepared in Example 3, and 6 parts by mass of talc powder into a high-speed mixer and knead at 160 °C for 8 min. Then add 40 parts by mass of epoxy acrylate rubber, 6 parts by mass of vinyl chloride-g-acrylate copolymer, 10 parts by mass of epoxy soybean oil, 15 parts by mass of ammonium polyphosphate, 5 parts by mass of pentaerythritol, 3 parts by mass of zinc borate, 0.6 parts by mass of antioxidant 1010, 0.3 parts by mass of antioxidant 168, 1 part by mass of antioxidant 4010, and 0.8 parts by mass of ultraviolet absorber UV531 and continue to knead at 140 °C for 10 min to obtain a premix; Add the above-obtained premix into a twin-screw extruder for extrusion. Set the temperature: zone 1 at 150 °C, zone 2 at 160 °C, die at 165 °C, screw speed at 30 rpm, vacuum degree at -0.06 MPa, and cool and shape at room temperature to obtain the HPVC power cable protection tube composition.

[0023] Example 6 A method for preparing an HPVC power cable protection tube includes the following steps: Add 100 parts by mass of high-strength polyvinyl chloride HD-3000, 3 parts by mass of calcium-zinc composite stabilizer, 13 parts by mass of the modified hydrotalcite obtained in Example 1, 0.3 parts by mass of β-diketone, 1 part by mass of calcium stearate, 15 parts by mass of the modified nano calcium carbonate prepared in Example 3, and 5 parts by mass of talc powder into a high-speed mixer and knead at 160 °C for 8 min. Then add 45 parts by mass of epoxy acrylate rubber, 6 parts by mass of vinyl chloride-g-acrylate copolymer, 12 parts by mass of epoxy soybean oil, 15 parts by mass of ammonium polyphosphate, 5 parts by mass of pentaerythritol, 3 parts by mass of zinc borate, 0.6 parts by mass of antioxidant 1010, 0.3 parts by mass of antioxidant 168, 1 part by mass of antiozonant 4010, and 0.8 parts by mass of ultraviolet absorber UV531 and continue to knead at 140 °C for 10 min to obtain a premix; Add the above-obtained premix into a twin-screw extruder for extrusion. Set the temperature: zone 1 at 150 °C, zone 2 at 160 °C, die at 165 °C, screw speed at 30 rpm, vacuum degree at -0.06 MPa, and cool and shape at room temperature to obtain the composition of the HPVC power cable protection pipe.

[0024] Example 7 A preparation method of an HPVC power cable protection pipe includes the following steps: Add 100 parts by mass of high-strength polyvinyl chloride HD-3000, 3 parts by mass of calcium-zinc composite stabilizer, 13 parts by mass of the modified hydrotalcite obtained in Example 2, 0.3 parts by mass of β-diketone, 1 part by mass of calcium stearate, 15 parts by mass of the modified nano calcium carbonate prepared in Example 3, and 5 parts by mass of talc powder into a high-speed mixer and knead at 160 °C for 8 min. Then add 45 parts by mass of epoxy acrylate rubber, 6 parts by mass of vinyl chloride-g-acrylate copolymer, 12 parts by mass of epoxy soybean oil, 15 parts by mass of ammonium polyphosphate, 5 parts by mass of pentaerythritol, 3 parts by mass of zinc borate, 0.6 parts by mass of antioxidant 1010, 0.3 parts by mass of antioxidant 168, 1 part by mass of antiozonant 4010, and 0.8 parts by mass of ultraviolet absorber UV531 and continue to knead at 140 °C for 10 min to obtain a premix; Add the above-obtained premix into a twin-screw extruder for extrusion. Set the temperature: zone 1 at 150 °C, zone 2 at 160 °C, die at 165 °C, screw speed at 30 rpm, vacuum degree at -0.06 MPa, and cool and shape at room temperature to obtain the composition of the HPVC power cable protection pipe.

[0025] Comparative Example 1 The preparation method of calcium-lanthanum hydrotalcite includes the following steps: Prepare a calcium nitrate solution with a concentration of 0.3 mol / L and a lanthanum nitrate solution with a concentration of 0.1 mol / L. Add the lanthanum nitrate solution to the calcium nitrate solution and stir under the condition of a water bath at 65 °C to obtain 100 mL of a mixed solution. Drop 100 mL of a sodium bicarbonate solution with a concentration of 0.1 mol / L and 100 mL of a sodium hydroxide solution with a concentration of 0.9 mol / L into the mixed solution using a dropping funnel, control the dropping rate of the funnel at 1 drop per second, monitor the pH, and always keep the pH of the suspension between 8 and 10. Stop dropping immediately when the pH of the suspension reaches 10, and keep the temperature constant for 4 h. During the constant temperature process, protect with N2. After the mixed solution ages, transfer it to a hydrothermal reaction kettle and react at 150 °C for 10 h. After the hydrothermal reaction ends, filter the solution, wash it until it is neutral, and dry it at 70 °C for 12 h to obtain calcium lanthanum hydrotalcite.

[0026] Comparative Example 2 Compared with Example 4, in Comparative Example 2, the modified hydrotalcite prepared in Example 1 added in Example 4 was replaced with an equal mass of calcium lanthanum hydrotalcite prepared in Example 1, and the other components and preparation methods were exactly the same as those in Example 4. The mechanical properties decreased.

[0027] Comparative Example 3 Compared with Example 4, in Comparative Example 3, no modified hydrotalcite was added, and the other components and preparation methods were exactly the same as those in Example 4.

[0028] Comparative Example 4 Compared with Example 4, in Comparative Example 4, no epoxy acrylate rubber and vinyl chloride-g-acrylate copolymer were added, and the other components and preparation methods were exactly the same as those in Example 4.

[0029] Performance Testing Tensile property test: The reference standard is GB / T1040.3-2006. Cut the HPVC power cable protection pipes obtained in Examples 4-7 and Comparative Examples 2-4 into dumbbell-shaped specimens with a thickness of 1 ± 0.1 mm according to the requirements of this standard. The tensile speed is 250 mm / min, and each group of test specimens shall not be less than 5; the test results are shown in Table 1; Notched impact strength: Test according to GB / T1843-2008, V-shaped notch. Cut the HPVC power cable protection pipes obtained in Examples 4-7 and Comparative Examples 2-4 into 80 mm × 100 mm × 4 mm, with a notch depth of 2 mm. Test 5 specimens for each formula and calculate the average value; the test results are shown in Table 1; Low-temperature impact resistance test: Place the HPVC power cable protection pipes obtained in Examples 4-7 and Comparative Examples 2-4 in a low-temperature test chamber at -40 °C for 1 h, then immediately take them out and bend them 180° with a bending diameter of 280 mm, and observe whether their sheaths are broken. Test 30 specimens for each formula. If it is below 15 / 30, it means that the temperature passes the low-temperature embrittlement impact test; the test results are shown in Table 1; Smoke density test: According to GB / T8323-2008, the HPVC power cable protection pipes obtained in Examples 4-7 and Comparative Examples 2-4 were placed into the smoke density tester JCY-2, with acetylene as the combustion gas, the test time was 3 min, and two groups of parallel experiments were carried out. If the data of the two groups differed greatly, the test was retested; the test results are shown in Table 1; Vertical burning test: Tested in accordance with GB / T 2408-2008, the UL-94 vertical burning test was carried out on the HPVC power cable protection pipes obtained in Examples 4-7 and Comparative Examples 2-4 using the Jiangning CZF-III vertical burning test machine; the test results are shown in Table 1; Congo red experiment: Tested according to GB / T2917.1-2002, the test paper was 10×30 mm and inserted into the test tube. The HPVC power cable protection pipes obtained in Examples 4-7 and Comparative Examples 2-4 were cut into 2×2×1 mm particles and placed into a large test tube for 50 mm, and placed in an oil bath at 180 °C. Start timing. When the Congo red test paper in the test tube changed from red to blue significantly, stop timing and record the time used Ts. Each sample was measured twice, and the average value was taken as the static thermal stability time of PVC; the test results are shown in Table 1; Table 1: Statistical table of test data of the specimens in Examples 4-7 and Comparative Examples 2-4

[0030] As can be seen from Table 1, the low temperature embrittlement temperature of the HPVC power cable protection pipes prepared in Examples 4-7 of the present invention can reach -40 °C, with excellent mechanical properties, good processing technology, good corrosion resistance, excellent flame retardant and smoke suppression properties, and can meet the production requirements of HPVC power cable protection pipes. In Comparative Example 2, unmodified calcium lanthanum hydrotalcite was added, and the smoke suppression and flame retardant effects of the obtained HPVC power cable protection pipe were reduced. In Comparative Example 3, modified hydrotalcite was not added, and the flame retardancy and smoke suppression properties of the obtained HPVC power cable protection pipe were greatly reduced, and the thermal stability time was also significantly reduced, indicating that the modified hydrotalcite added in the present invention can play the role of auxiliary heat stabilizer and smoke suppression and flame retardant. In Comparative Example 4, epoxy acrylate rubber and vinyl chloride-g-acrylate copolymer were not added, and the cold resistance of the obtained HPVC power cable protection pipe was greatly reduced, and the mechanical properties were also reduced.

[0031] In the description of this specification, the descriptions referring to terms such as "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0032] The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. An HPVC power cable protection pipe, characterized in that, Comprising at least the following raw materials by weight: 100 parts of high-strength polyvinyl chloride, 35 - 45 parts of epoxy acrylate rubber, 5 - 8 parts of vinyl chloride-g-acrylate copolymer, 8 - 12 parts of epoxy soybean oil, 3 - 5 parts of calcium-zinc composite stabilizer, 5 - 15 parts of modified hydrotalcite, 0.1 - 0.5 of β-diketone, 0.8 - 1.5 parts of calcium stearate, 10 - 20 parts of flame retardant, 12 - 15 parts of modified nano calcium carbonate, 5 - 8 parts of talcum powder, 0.6 - 1.2 parts of antioxidant, 1 - 2 parts of antioxidant 4010, 0.5 - 1.5 of ultraviolet absorber UV531; The modified hydrotalcite is calcium-lanthanum hydrotalcite modified by sodium dodecyl sulfate, and the modified hydrotalcite is obtained by adding a mixed solution of calcium nitrate and lanthanum nitrate, sodium hydroxide solution and sodium bicarbonate solution to the sodium dodecyl sulfate solution, mixing and aging, and then performing a post-treatment process.

2. The HPVC power cable protection pipe according to claim 1, characterized in that, The molar ratio of calcium ions to lanthanum ions in the modified hydrotalcite is 3 - 4:

1.

3. The HPVC power cable protection pipe according to claim 2, characterized in that, The concentration of calcium nitrate in the mixed solution is 0.1 - 0.15 mol / L, and the concentration of lanthanum nitrate in the mixed solution is 0.3 - 0.5 mol / L.

4. The HPVC power cable protection pipe according to claim 2, characterized in that, The concentration of the sodium hydroxide solution is 0.8 - 1 mol / L, the concentration of the sodium bicarbonate solution is 0.1 - 0.2 mol / L, and the concentration of the sodium dodecyl sulfate solution is 4 - 5 g / mL.

5. The HPVC power cable protection pipe according to claim 1, characterized in that, The antioxidant is composed of 0.4 - 0.8 parts of antioxidant 1010 and 0.2 - 0.4 parts of antioxidant 168.

6. The HPVC power cable protection pipe according to claim 1, wherein, The flame retardant is composed of 12 - 18 parts of ammonium polyphosphate, 3 - 6 parts of pentaerythritol and 2 - 4 parts of zinc borate.

7. The HPVC power cable protection pipe according to claim 1, characterized in that, The modified nano calcium carbonate is obtained by mixing a titanate coupling agent with absolute ethanol, then mixing with nano calcium carbonate, and reacting through a subsequent treatment process.

8. The HPVC power cable protection pipe according to claim 7, characterized in that, The mass ratio of the nano calcium carbonate to the titanate coupling agent is 100:1 - 2.

9. A preparation method of an HPVC power cable protection pipe, characterized in that, At least including the following preparation steps: Adding high-strength polyvinyl chloride, calcium-zinc composite stabilizer, modified hydrotalcite, β-diketone, calcium stearate, modified nano calcium carbonate and talcum powder into a high-speed mixer for mixing, and then adding epoxy acrylate rubber, vinyl chloride-g-acrylate copolymer, epoxy soybean oil, flame retardant, antioxidant, antioxidant 4010 and ultraviolet absorber UV531 to continue mixing to obtain a premix; Adding the premix into a twin-screw extruder for extrusion and cooling and shaping to obtain an HPVC power cable protection pipe.

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