HPVC power cable protection pipe and preparation method thereof

Abstract

The application discloses 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 pipe comprises the following raw materials by weight: 100 parts of high-strength polyvinyl chloride, 35-45 parts of epoxy-type 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 parts of beta-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 anti-aging agent 4010 and 0.5-1.5 parts of ultraviolet 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 sodium dodecyl sulfate solution, mixing and aging, and then performing a post-treatment process.The HPVC power cable protection pipe prepared by the application has high strength, good mechanical properties, weather resistance and cold resistance, and a long service life.

Description

Technical Field

[0001] The present invention relates to the technical field of cable protection tubes, and in particular to an HPVC power cable protection tube and a preparation method thereof. Background Art

[0002] Polyvinyl chloride (PVC) is one of the general plastic varieties that was developed earlier, has the largest output, and is most widely used in my country. Ordinary soft polyvinyl chloride 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-end products. High-polymerization polyvinyl chloride (HPVC) generally refers to polyvinyl chloride resins with an average degree of polymerization greater than 1700. HPVC has a large plasticizer absorption capacity, and its products greatly improve 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 (flame retardant), but when it is used as a cable material, a 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 plasticizers will cause the oxygen index of polyvinyl chloride materials to drop significantly. When an electrical short circuit occurs in the cable and causes the cable to catch fire, the cable is very easy to spread and produce a lot of smoke, which seriously affects the deployment of rescue work and causes significant property losses. Therefore, it is necessary to improve the flame retardant, fire retardant and smoke suppression properties of PVC materials;

[0003] Furthermore, power cables are often laid outdoors. As power cables age and vary depending on the environment, problems with their use are gradually becoming apparent. For example, high summer temperatures accelerate aging; low winter temperatures cause changes in the cable's internal metal structure; soil and plant environments corrode and wear the cable's exterior; and cables exhibit poor weather resistance, cracking during outdoor use and failing to meet outdoor requirements. Consequently, existing PVC conduit materials suffer from deficiencies such as poor processing performance, low-temperature performance, and weather resistance, significantly limiting their use. Summary of the Invention

[0004] The purpose of the present invention is to provide an HPVC power cable protection tube and a preparation method thereof to solve the following technical problems:

[0005] Existing HPVC power cable protection tubes have problems such as poor flame retardancy and smoke suppression, poor processing performance, and insufficient low-temperature resistance.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] An HPVC power cable protection tube comprises at least the following raw materials in parts by weight:

[0008] 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 parts 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 talc, 0.6-1.2 parts of antioxidant, 1-2 parts of antioxidant 4010, 0.5-1.5 parts of ultraviolet absorber UV531;

[0009] The modified hydrotalcite is calcium lanthanum hydrotalcite modified with sodium dodecyl sulfate, and 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 sodium dodecyl sulfate solution, mixing and aging, and then performing a post-treatment process.

[0010] As a further embodiment of the present invention, the molar ratio of calcium ions to lanthanum ions in the modified hydrotalcite is 3-4:1.

[0011] As a further embodiment of the present invention, the concentration of the calcium nitrate in the mixed solution is 0.1-0.15 mol / L, and the concentration of the lanthanum nitrate in the mixed solution is 0.3-0.5 mol / L.

[0012] As a further embodiment 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 lauryl sulfate solution is 4-5 g / mL.

[0013] As a further embodiment 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.

[0014] As a further embodiment 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.

[0015] As a further solution of the present invention: the modified nano-calcium carbonate is mixed with a titanate coupling agent and anhydrous ethanol, and then mixed with nano-calcium carbonate, and the reaction is carried out through a subsequent treatment process to obtain the modified nano-calcium carbonate.

[0016] As a further solution of the present invention: the mass ratio of the nano-calcium carbonate to the titanate coupling agent is 100:1-2.

[0017] A method for preparing an HPVC power cable protective tube comprises at least the following steps:

[0018] High-strength polyvinyl chloride, calcium-zinc composite stabilizer, modified hydrotalcite, β-diketone, calcium stearate, modified nano-calcium carbonate and talc are added into a high-speed mixer and mixed, and then epoxy acrylate rubber, vinyl chloride-g-acrylate copolymer, epoxy soybean oil, flame retardant, antioxidant, antioxidant 4010 and ultraviolet absorber UV531 are added and mixed to obtain a premix;

[0019] The premix is ​​added into a twin-screw extruder for extrusion, cooled and shaped to obtain an HPVC power cable protection tube.

[0020] Beneficial effects of the present invention:

[0021] The HPVC power cable protection tube prepared in the present invention is mainly composed of high-strength polyvinyl chloride, epoxy acrylate rubber, and plasticizer. The HPVC itself has high mechanical strength and chemical corrosion resistance, making it suitable as a power cable protective sheath. The added epoxy acrylate rubber can improve the toughness of the HPVC, especially its low-temperature brittleness, and also improve the weather resistance of the HPVC power cable protection tube. In addition, a calcium-zinc composite stabilizer, modified hydrotalcite, B-diketone, calcium stearate, flame retardant, modified nano-calcium carbonate, talcum powder, antioxidant, antioxidant 4010, and ultraviolet absorber UV531 are added to improve the overall performance of the material. The HPVC power cable protection tube obtained by the present invention has high strength, good mechanical properties, and both weather resistance and cold resistance. It can be used in saline-alkali areas and severely cold regions, effectively ensuring the operational reliability of cable lines, with huge economic and social benefits and broad application prospects.

[0022] In the present invention, the epoxy acrylate rubber added to the high-strength polyvinyl chloride (HPVC) base material partially crosslinks with the HPVC through epoxy groups, forming an interpenetrating network structure. This gives the material both high toughness and impact resistance, and its low-temperature brittleness temperature can be reduced to below -40°C. Furthermore, while HPVC itself is resistant to acid, alkali, and salt corrosion, the epoxy acrylate rubber further reduces environmental permeation, improving the composite material's weather resistance and extending the service life of the protective cover in harsh environments. The present invention also uses a vinyl chloride-g-acrylate copolymer as a compatibilizer for the epoxy acrylate rubber and high-strength polyvinyl chloride. Its molecular chain contains both polyvinyl chloride structural units, which can be fully embedded in the long-chain segments of high-molecular-weight polyvinyl chloride, and an acrylate structure similar to the main monomer structure of the acrylate rubber, resulting in excellent compatibility. Therefore, the vinyl chloride-g-acrylate copolymer acts as a bridge, combining the plastic and rubber phases to achieve good interfacial adhesion, thereby improving the mechanical properties of the composite material.

[0023] The HPVC power cable protection tube of the present invention further comprises modified hydrotalcite, which is calcium-lanthanum hydrotalcite modified with a surface modifier. The modified hydrotalcite added in the present invention can serve as an auxiliary thermal stabilizer, synergistically improving thermal stability with the thermal stabilizer calcium-zinc composite stabilizer. The calcium-zinc composite stabilizer reacts with calcium stearate and zinc stearate with HCl generated by the decomposition of PVC to produce calcium chloride / zinc chloride, which inhibits the autocatalytic degradation of HCl. The calcium-lanthanum hydrotalcite, as a layered double hydroxide, has interlayer hydroxyl groups and anions that can adsorb HCl and immobilize chloride ions through ion exchange. The Lewis acidity of the lanthanum ions catalyzes the neutralization reaction of HCl, achieving dual-path HCl capture. Furthermore, the layered structure of the hydrotalcite acts as a physical barrier to inhibit the diffusion of degradation products, significantly improving the thermal stability of the HPVC power cable protection tube and processing performance. The flame retardants in this invention are ammonium polyphosphate, pentaerythritol, and zinc borate. The modified hydrotalcite also produces a synergistic flame-retardant effect with the flame retardants. The calcium oxide and lanthanum oxide decomposed from the hydrotalcite can be embedded in the expanded porous carbon layer formed by the ammonium polyphosphate and pentaerythritol, improving the density and high-temperature resistance of the elastic layer. The hydrotalcite can also absorb HCl, reducing toxic fumes. After being modified with a surfactant, the hydrotalcite can also release more CO2, preventing the combustion of polyvinyl chloride (PVC) and improving its flame retardant and smoke suppression properties. The addition of a surfactant to the calcium-lanthanum hydrotalcite in this invention can improve the dispersibility of the hydrotalcite in PVC and enhance its fluidity in the PVC, thereby imparting good mechanical properties to the PVC.

[0024] The present invention also incorporates modified nano-calcium carbonate and hydrotalcite. The combination of calcium carbonate and talc improves the material's impact strength, flexural strength, flexural modulus, and dimensional stability. The modified nano-calcium carbonate and talc fill the gaps between the matrix, forming entanglements between the matrix surface and the filler. These entanglements help improve interfacial adhesion and increase notched impact strength. The nano-calcium carbonate enhances the impact strength of the HPVC power cable protective tube, while the talc enhances its strength, achieving a synergistic effect of both rigidity and flexibility. Furthermore, the nano-calcium carbonate is surface-modified using a titanate coupling agent. The titanate reduces filler-PVC interface friction, while the talc flakes act as a lubricant, improving the processing performance of the HPVC power cable protective tube. DETAILED DESCRIPTION

[0025] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0026] Example 1 The preparation method of modified hydrotalcite comprises the following steps:

[0027] 2 g of sodium lauryl sulfate was dissolved in 50 mL of deionized water to obtain a sodium lauryl sulfate solution, which was placed in an 80°C oil bath and filled with N2 gas. Then, 100 mL of a mixed solution of 0.3 mol / L calcium nitrate and 0.1 mol / L lanthanum nitrate, 100 mL of a 0.1 mol / L sodium bicarbonate solution, and 100 mL of a 0.9 mol / L sodium hydroxide solution were added dropwise to the sodium lauryl sulfate solution using a dropping funnel. The dropping rate of the funnel was controlled to be 1 drop per second. The pH was monitored to keep the pH of the suspension at 8-10. The addition was stopped when the pH of the suspension reached 10. The temperature was kept constant for 4 h. During the constant temperature process, N2 protection was passed through. After the mixed solution was aged, it was transferred to a hydrothermal reactor and reacted at 150°C for 10 h. After the hydrothermal reaction was completed, it was filtered, washed with anhydrous ethanol and high-purity water until neutral, and dried at 70°C for 12 h to obtain modified hydrotalcite.

[0028] Example 2 The preparation method of modified hydrotalcite comprises the following steps:

[0029] 2 g of sodium lauryl sulfate was dissolved in 50 mL of deionized water to obtain a sodium lauryl sulfate solution, which was placed in an 80°C oil bath and filled with N2 gas. Then, 100 mL of a mixed solution of 0.3 mol / L calcium nitrate and 0.1 mol / L lanthanum nitrate, 100 mL of a 0.2 mol / L sodium bicarbonate solution, and 100 mL of a 1 mol / L sodium hydroxide solution were added dropwise to the sodium lauryl sulfate solution using a dropping funnel. The dropping rate of the funnel was controlled to be 1 drop per second. The pH was monitored to keep the pH of the suspension at 8-10. The addition was stopped when the pH of the suspension reached 10. The temperature was kept constant for 4 h. During the constant temperature process, N2 protection was passed through. After the mixed solution was aged, it was transferred to a hydrothermal reactor and reacted at 150°C for 10 h. After the hydrothermal reaction was completed, it was filtered, washed with anhydrous ethanol and high-purity water until neutral, and dried at 70°C for 12 h to obtain modified hydrotalcite.

[0030] Example 3 The preparation method of modified nano calcium carbonate comprises the following steps:

[0031] 1.5 g of titanate coupling agent and anhydrous ethanol were placed in a beaker and stirred in a constant temperature water bath of 80°C for 30 min. Subsequently, 100 g of nano-calcium carbonate powder was added and stirred for 30 min. The mixture was filtered, vacuum dried at 60°C for 30 min, and dried in an oven at 140°C for 1 h. After drying, the mixture was alternately washed with anhydrous ethanol and high-purity water three times, dried again, and crushed to obtain modified nano-calcium carbonate.

[0032] Example 4 A method for preparing an HPVC power cable protective tube comprises the following steps:

[0033] 100 parts by mass of high-strength polyvinyl chloride DH-3000, 4 parts by mass of calcium-zinc composite stabilizer, 10 parts by mass of 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 modified nano-calcium carbonate prepared in Example 3, and 6 parts by mass of talc were added into a high-speed mixer and kneaded at 160° C. for 8 min, and then 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 were added and kneaded at 140° C. for 10 min to obtain a premix;

[0034] The premix obtained above was added to a twin-screw extruder for extrusion, with the temperature set at 150°C for zone 1, 160°C for zone 2, 165°C for the die head, 30 rpm for the screw speed, and a vacuum degree of -0.06 MPa. The HPVC power cable protective tube was obtained by cooling and shaping at room temperature.

[0035] Example 5 A method for preparing an HPVC power cable protective tube comprises the following steps:

[0036] 100 parts by mass of high-strength polyvinyl chloride DH-3000, 4 parts by mass of calcium-zinc composite stabilizer, 10 parts by mass of 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 modified nano-calcium carbonate prepared in Example 3, and 6 parts by mass of talc were added to a high-speed mixer and kneaded at 160° C. for 8 min, and then 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 were added and kneaded at 140° C. for 10 min to obtain a premix;

[0037] The premix obtained above was added to a twin-screw extruder for extrusion, with the temperature set at 150°C for zone 1, 160°C for zone 2, 165°C for the die head, 30 rpm for the screw speed, and a vacuum degree of -0.06 MPa. The HPVC power cable protective tube was obtained by cooling and shaping at room temperature.

[0038] Example 6 A method for preparing an HPVC power cable protective tube comprises the following steps:

[0039] 100 parts by mass of high-strength polyvinyl chloride DH-3000, 3 parts by mass of calcium-zinc composite stabilizer, 13 parts by mass of 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 modified nano-calcium carbonate prepared in Example 3, and 5 parts by mass of talc were added to a high-speed mixer and kneaded at 160° C. for 8 min, and then 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 antioxidant 4010, and 0.8 parts by mass of ultraviolet absorber UV531 were added and kneaded at 140° C. for 10 min to obtain a premix;

[0040] The premix obtained above was added to a twin-screw extruder for extrusion, with the temperature set at 150°C for zone 1, 160°C for zone 2, 165°C for the die head, 30 rpm for the screw speed, and a vacuum degree of -0.06 MPa. The HPVC power cable protective tube was obtained by cooling and shaping at room temperature.

[0041] Example 7 A method for preparing an HPVC power cable protective tube comprises the following steps:

[0042] 100 parts by mass of high-strength polyvinyl chloride DH-3000, 3 parts by mass of calcium-zinc composite stabilizer, 13 parts by mass of 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 modified nano-calcium carbonate prepared in Example 3, and 5 parts by mass of talc were added to a high-speed mixer and kneaded at 160° C. for 8 min, and then 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 antioxidant 4010, and 0.8 parts by mass of ultraviolet absorber UV531 were added and kneaded at 140° C. for 10 min to obtain a premix;

[0043] The premix obtained above was added to a twin-screw extruder for extrusion, with the temperature set at 150°C for zone 1, 160°C for zone 2, 165°C for the die head, 30 rpm for the screw speed, and a vacuum degree of -0.06 MPa. The HPVC power cable protective tube was obtained by cooling and shaping at room temperature.

[0044] Comparative Example 1 The preparation method of calcium lanthanum hydrotalcite comprises the following steps:

[0045] 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 were prepared, the lanthanum nitrate solution was added to the calcium nitrate solution, and stirred in a water bath at 65° C. to obtain 100 mL of a mixed solution. 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 were added dropwise to the mixed solution using a dropping funnel. The funnel drop rate was controlled to be 1 drop per second. The pH was monitored to always maintain the pH of the suspension at 8-10. When the pH of the suspension reached 10, the dropwise addition was stopped immediately. The constant temperature was maintained for 4 hours. During the constant temperature process, N2 protection was passed. After the mixed solution was aged, it was transferred to a hydrothermal reactor and reacted at 150° C. for 10 hours. After the hydrothermal reaction was completed, the solution was filtered, washed to neutrality, and dried at 70° C. for 12 hours to obtain calcium lanthanum hydrotalcite.

[0046] Comparative Example 2 Compared with Example 4, Comparative Example 2 only replaces the modified hydrotalcite prepared in Example 1 added in Example 4 with the calcium lanthanum hydrotalcite prepared in Example 1. The other components and preparation method are completely the same as those in Example 4.

[0047] Comparative Example 3 Compared with Example 4, in Comparative Example 3, no modified hydrotalcite was added, and the remaining components and preparation method were completely consistent with those of Example 4.

[0048] Comparative Example 4 Compared with Example 4, in Comparative Example 4, epoxy acrylate rubber and vinyl chloride-g-acrylate copolymer were not added, and the remaining components and preparation method were completely consistent with those of Example 4.

[0049] Performance testing

[0050] Tensile Properties Test: Based on the GB / T1040.3-2006 standard, the HPVC power cable protection tubes obtained in Examples 4-7 and Comparative Examples 2-4 were cut into dumbbell-shaped specimens with a thickness of 1±0.1 mm. The tensile speed was 250 mm / min, and each test set consisted of at least five specimens. The test results are shown in Table 1.

[0051] Notched impact strength: tested in accordance with GB / T1843-2008, using a V-notch. The HPVC power cable protection tubes obtained in Examples 4-7 and Comparative Examples 2-4 were cut into 80 mm × 100 mm × 4 mm pieces with a notch depth of 2 mm. Five specimens were tested for each formulation, and the average value was calculated. The test results are shown in Table 1.

[0052] Low-temperature impact resistance test: The HPVC power cable protective tubes obtained in Examples 4-7 and Comparative Examples 2-4 were placed in a -40°C low-temperature test chamber for 1 hour, then immediately removed and bent 180° with a bend diameter of 280 mm to observe whether the sheaths fractured. Thirty specimens were tested for each formulation, with a value below 15 / 30 indicating that the tubes passed the low-temperature embrittlement impact test. The test results are shown in Table 1.

[0053] Smoke density test: According to GB / T8323-2008, the HPVC power cable protective tubes obtained in Examples 4-7 and Comparative Examples 2-4 were placed in a JCY-2 smoke density tester, using acetylene as the combustion gas. The test lasted 3 minutes. Two groups were tested in parallel. If the two groups of data differed significantly, the test was repeated. The test results are shown in Table 1.

[0054] Vertical combustion test: According to GB / T 2408-2008, the HPVC power cable protection tubes obtained in Examples 4-7 and Comparative Examples 2-4 were subjected to UL-94 vertical combustion test using a Jiangning CZF-III vertical combustion tester. The test results are shown in Table 1.

[0055] Congo Red Test: According to GB / T2917.1-2002, a 10×30 mm test paper was inserted into a test tube. The HPVC power cable protective tubes 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 with a size of 50 mm. The tube was then placed in an oil bath at 180°C. The timer was started and stopped when the Congo Red test paper in the test tube clearly turned from red to blue. The time, Ts, was recorded. Each sample was measured twice, and the average of the results was taken as the static thermal stability time of the PVC. The test results are shown in Table 1.

[0056] Table 1: Statistical table of performance test data of test pieces of Examples 4-7 and Comparative Examples 2-4

[0057]

[0058] As shown in Table 1, the HPVC power cable protection tubes prepared in Examples 4-7 of the present invention can reach a low-temperature brittle temperature of -40°C, exhibit excellent mechanical properties, smooth processing, good corrosion resistance, and outstanding flame retardancy and smoke suppression, meeting the production requirements for HPVC power cable protection tubes. In Comparative Example 2, the addition of unmodified calcium lanthanum hydrotalcite reduced the smoke suppression and flame retardancy of the resulting HPVC power cable protection tube. In Comparative Example 3, the absence of modified hydrotalcite significantly reduced the flame retardancy and smoke suppression of the resulting HPVC power cable protection tube, and significantly shortened the thermal stability time, demonstrating that the modified hydrotalcite added in the present invention can act as an auxiliary thermal stabilizer and smoke suppressant. In Comparative Example 4, the absence of epoxy acrylate rubber and vinyl chloride-g-acrylate copolymer resulted in significantly reduced cold resistance and mechanical properties of the resulting HPVC power cable protection tube.

[0059] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0060] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and modifications fall within the scope of the invention as claimed.

Claims

1. A HPVC power cable protection tube, characterized in that: At least include 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 parts 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 talc, 0.6-1.2 parts of antioxidant, 1-2 parts of antioxidant 4010, and 0.5-1.5 parts of ultraviolet absorber UV531; The modified hydrotalcite is calcium lanthanum hydrotalcite modified with sodium dodecyl sulfate, and 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; The flame retardant is composed of 12-18 parts of ammonium polyphosphate, 3-6 parts of pentaerythritol and 2-4 parts of zinc borate; The high-strength polyvinyl chloride is DH-3000.

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

4. The HPVC power cable protection tube 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 lauryl sulfate solution is 4-5 g / mL.

5. The HPVC power cable protection tube 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 tube according to claim 1, characterized in that: The preparation method of the modified nano-calcium carbonate comprises the following steps: mixing a titanate coupling agent with anhydrous ethanol, and then mixing the mixture with nano-calcium carbonate, and reacting the mixture through a subsequent treatment process to obtain the modified nano-calcium carbonate.

7. The HPVC power cable protection tube according to claim 6, characterized in that: The mass ratio of the nano-calcium carbonate to the titanate coupling agent is 100:1-2.

8. A method for preparing the HPVC power cable protection tube according to any one of claims 1 to 7, characterized in that: The method comprises at least the following preparation steps: High-strength polyvinyl chloride, calcium-zinc composite stabilizer, modified hydrotalcite, β-diketone, calcium stearate, modified nano-calcium carbonate and talc are added into a high-speed mixer and mixed, and then epoxy acrylate rubber, vinyl chloride-g-acrylate copolymer, epoxy soybean oil, flame retardant, antioxidant, antioxidant 4010 and ultraviolet absorber UV531 are added and mixed to obtain a premix; The premix is ​​added into a twin-screw extruder for extrusion, cooled and shaped to obtain an HPVC power cable protection tube.

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