Impact-resistant cold-resistant polyvinyl chloride wire tube and preparation method thereof

Abstract

This invention discloses a method for preparing impact-resistant and cold-resistant polyvinyl chloride (PVC) conduit, belonging to the field of PVC material technology. In this invention, butyl rubber is complexed with dioctyl sebacate and active silica under the initiation of tert-butyl hydrogen peroxide. This complex acts as a flexible dispersed phase in the PVC matrix, effectively absorbing and dissipating impact energy and lowering the glass transition temperature of the material. This allows the conduit to maintain excellent toughness and crack resistance even at low temperatures. Furthermore, it works synergistically with impact modifiers in the system. Ethylene-vinyl acetate copolymer provides elastomer toughening, while maleic anhydride-styrene graft copolymer acts as a highly efficient compatibilizer and interfacial reinforcing agent. The compounded structure forms a toughening network, achieving toughening from molecular chain segment movement to microstructure, thus improving impact strength. Subsequent addition of reinforcing fibers of the same specification further enhances the strength of the conduit. Overall, this results in a PVC conduit with excellent strength, impact and cold resistance, and thermal properties.

Description

Technical Field

[0001] This invention relates to the field of PVC material technology, and more specifically, to an impact-resistant and cold-resistant polyvinyl chloride conduit and its preparation method. Background Technology

[0002] Polyvinyl chloride (PVC), as a general-purpose plastic, is widely used in construction, municipal engineering, and electrical fields due to its advantages such as light weight, corrosion resistance, good insulation, and low cost, especially in products such as conduits and drainage pipes. However, traditional PVC materials have defects such as high low-temperature brittleness and insufficient impact resistance. Especially when used in cold regions or low-temperature environments, the pipes are prone to cracking, affecting their service life and safety. In addition, ordinary PVC has poor weather resistance, and long-term exposure to outdoor environments can easily lead to aging, discoloration, and decreased strength, limiting its application in harsh environments.

[0003] Currently, common methods for improving the low-temperature toughness and weather resistance of PVC include adding plasticizers, elastomer toughening agents, or inorganic fillers. However, the addition of plasticizers often leads to a decrease in the material's heat resistance and facilitates migration and precipitation, affecting long-term performance. While ordinary elastomers (such as CPE and ACR) can improve toughness, their toughening effect is limited at low temperatures and may impair the material's rigidity, heat resistance, and processing fluidity. Therefore, developing a modification method that can significantly improve the low-temperature impact resistance of PVC while also maintaining weather resistance, heat resistance, and processing stability has become a pressing technical challenge for the industry.

[0004] In recent years, research on improving the performance of PVC through elastomer modification has been increasing. Among them, ethylene propylene diene monomer (EPDM) rubber is considered an ideal toughening candidate material due to its excellent low-temperature flexibility, weather resistance, and heat aging resistance. However, EPDM is a non-polar rubber with poor compatibility with polar PVC. Direct blending easily leads to phase separation, affecting the toughening effect. Therefore, functional modification of EPDM is necessary to introduce polar groups to enhance its interfacial bonding with PVC. Multi-monomer melt grafting modification is one of the effective means to achieve this goal. By grafting monomers containing polar functional groups onto the EPDM molecular chain, its compatibility with PVC can be significantly improved, thereby maintaining the balance of the overall material performance while improving toughness. Summary of the Invention

[0005] Based on this, in order to solve one of the above-mentioned technical problems, the present invention provides an impact-resistant and cold-resistant polyvinyl chloride conduit and its preparation method, the specific technical solution of which is as follows:

[0006] An impact-resistant and cold-resistant polyvinyl chloride (PVC) conduit, the PVC conduit comprising the following raw materials in parts by weight: 80-100 parts of polyvinyl chloride resin, 5-15 parts of impact-resistant and cold-resistant additives, 1-5 parts of impact modifier, 0.2-5 parts of composite heat stabilizer, 8-15 parts of reinforcing filler, 1-2 parts of dispersant, 0.5-3 parts of lubricant, and 0.5-2 parts of plasticizer.

[0007] Furthermore, the preparation method of the impact-resistant and cold-resistant additive is as follows: butyl rubber is added to tetrahydrofuran, heated to 85℃~100℃, stirred at a speed of 300r / min~500r / min for 20min~30min, then tert-butyl hydroperoxide, dioctyl sebacate and active silica are added, and the reaction is continued to be stirred for 1h~3h to obtain the impact-resistant and cold-resistant additive.

[0008] Furthermore, the impact modifier is obtained by mixing ethylene-vinyl acetate copolymer and maleic anhydride-styrene graft copolymer in a mass ratio of (1~3):(1~5).

[0009] Furthermore, the composite heat stabilizer includes a first heat stabilizer and a second heat stabilizer, wherein the first heat stabilizer is at least one of calcium-zinc heat stabilizer and organotin heat stabilizer; and the second heat stabilizer is at least one of stearoylbenzoylmethane and hydrotalcite.

[0010] Further, the method for preparing the reinforcing filler is as follows: adding reinforcing fibers to an alcohol solution of coupling agent, heating to 55℃~60℃, stirring at a speed of 50r / min~100r / min for 1h~5h, filtering, washing, and drying to obtain the reinforcing filler.

[0011] Furthermore, the reinforcing fiber is a mixture of basalt fiber and glass fiber of different specifications; wherein the average length of the basalt fiber is 15~25μm and the diameter is 0.5~1.0μm; and the average length of the glass fiber is 3~8μm and the diameter is 0.5~1.0μm.

[0012] Furthermore, the dispersant is at least one of polyvinyl alcohol, polyvinyl acetate, and hydroxypropyl methylcellulose.

[0013] Furthermore, the lubricant is at least one of calcium stearate, pentaerythritol stearate, oxidized polyethylene wax, and ethylene bis-stearamide.

[0014] Furthermore, the plasticizer is at least one of epoxidized soybean oil and dioctyl terephthalate.

[0015] In addition, the present invention also provides a method for preparing an impact-resistant and cold-resistant polyvinyl chloride conduit, the method comprising the following steps: S1. Add polyvinyl chloride resin, impact and cold-resistant additives, impact modifiers, composite heat stabilizers, reinforcing fillers, dispersants, lubricants, and plasticizers to a mixer for mixing to obtain a mixture; S2. The mixture is added to a twin-screw extruder for melting, extruded through a die, cooled and sized to obtain an impact-resistant and cold-resistant polyvinyl chloride conduit.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention involves complexing butyl rubber with dioctyl sebacate and active silica under the initiation of tert-butyl hydrogen peroxide. This complex acts as a flexible dispersed phase within the PVC matrix, effectively absorbing and dissipating impact energy, significantly reducing the glass transition temperature of the material. This allows the conduit to maintain excellent toughness and crack resistance even at low temperatures, reducing the risk of brittle fracture. Furthermore, it works synergistically with impact modifiers in the system. The ethylene-vinyl acetate copolymer provides elastomer toughening, while the maleic anhydride-styrene graft copolymer acts as a highly efficient compatibilizer and interfacial reinforcing agent. After compounding, these components form a toughening network, achieving toughening from molecular chain segment movement to the microstructure, thus contributing to improved impact strength.

[0017] 2. This invention uses reinforcing fibers of different specifications for modification treatment. Basalt fibers and glass fibers of different lengths and diameters are mixed to construct a multi-layered and dense reinforcing network in the matrix. Among them, the shorter fibers play the role of filling and stress transfer, while the longer fibers can more effectively bear the load. After modification treatment, it helps to improve the interfacial compatibility with PVC resin, reduce interfacial defects, and ensure the efficient transfer of stress from the matrix to the fibers, thereby obtaining PVC conduit with high impact toughness, good flattening resistance, dimensional stability, and resistance to deformation. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to its embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the scope of protection of the invention.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0020] An embodiment of the present invention provides an impact-resistant and cold-resistant polyvinyl chloride (PVC) conduit, the PVC conduit comprising the following raw materials in parts by weight: 80-100 parts of polyvinyl chloride resin, 5-15 parts of impact-resistant and cold-resistant additives, 1-5 parts of impact modifier, 0.2-5 parts of composite heat stabilizer, 8-15 parts of reinforcing filler, 1-2 parts of dispersant, 0.5-3 parts of lubricant, and 0.5-2 parts of plasticizer.

[0021] In one embodiment, the impact-resistant and cold-resistant additive is prepared by adding butyl rubber to tetrahydrofuran, heating to 85°C to 100°C, stirring at 300 r / min to 500 r / min for 20 min to 30 min, then adding tert-butyl hydroperoxide, dioctyl sebacate, and active silica, and continuing to stir and react for 1 h to 3 h to obtain the impact-resistant and cold-resistant additive.

[0022] In one embodiment, the ratio of butyl rubber, tetrahydrofuran, tert-butyl hydroperoxide, dioctyl sebacate and active silica by weight is (5~10):(15~20):(0.5~1):(1~5):(1~3).

[0023] In one embodiment, the impact modifier is obtained by mixing an ethylene-vinyl acetate copolymer and a maleic anhydride-styrene graft copolymer in a mass ratio of (1~3):(1~5).

[0024] In one embodiment, the composite heat stabilizer includes a first heat stabilizer and a second heat stabilizer, wherein the first heat stabilizer is at least one of a calcium-zinc heat stabilizer and an organotin heat stabilizer; and the second heat stabilizer is at least one of a stearoylbenzoylmethane and hydrotalcite.

[0025] In one embodiment, the weight ratio of the heat stabilizer to the second heat stabilizer is (1~3):(1~2). This invention employs a composite heat stabilizer, where the first heat stabilizer provides primary stabilization; the second heat stabilizer, as an auxiliary and synergistic agent, further neutralizes acidic substances and replaces unstable chlorine atoms, effectively inhibiting the thermal degradation and discoloration of PVC resin, ensuring uniform and stable quality during processing, and extending the overall service life.

[0026] In one embodiment, the method for preparing the reinforcing filler is as follows: adding reinforcing fibers to an alcohol solution of a coupling agent, heating to 55°C to 60°C, stirring at a speed of 50 r / min to 100 r / min for 1 h to 5 h, filtering, washing, and drying to obtain the reinforcing filler.

[0027] In one embodiment, the alcohol solution of the coupling agent is obtained by mixing a silane coupling agent, ethanol and water in a volume ratio of (1~5):(1~3):(1~3).

[0028] In one embodiment, the silane coupling agent is at least one of vinyltris(β-methoxyethoxy)silane, n-octyltriethoxysilane, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane, and 3-mercaptopropyltriethoxysilane.

[0029] In one embodiment, the weight ratio of the reinforcing fiber to the alcohol solution of the coupling agent is (3~7):(10~15).

[0030] In one embodiment, the reinforcing fiber is a mixture of basalt fiber and glass fiber of different specifications; wherein the basalt fiber has an average length of 15~25μm and a diameter of 0.5~1.0μm; and the glass fiber has an average length of 3~8μm and a diameter of 0.5~1.0μm.

[0031] In one embodiment, the weight ratio of the basalt fiber to the glass fiber is (1~7):(1~10).

[0032] In one embodiment, the dispersant is at least one of polyvinyl alcohol, polyvinyl acetate, and hydroxypropyl methylcellulose.

[0033] In one embodiment, the lubricant is at least one of calcium stearate, pentaerythritol stearate, oxidized polyethylene wax, and ethylene bis-stearamide.

[0034] In one embodiment, the plasticizer is at least one of epoxidized soybean oil and dioctyl terephthalate.

[0035] In addition, the present invention also provides a method for preparing an impact-resistant and cold-resistant polyvinyl chloride conduit, the method comprising the following steps: S1. Add polyvinyl chloride resin, impact and cold-resistant additives, impact modifiers, composite heat stabilizers, reinforcing fillers, dispersants, lubricants, and plasticizers to a mixer for mixing to obtain a mixture; S2. The mixture is added to a twin-screw extruder for melting, extruded through a die, cooled and sized to obtain an impact-resistant and cold-resistant polyvinyl chloride conduit.

[0036] In one embodiment, in step S1, the mixing speed is 500 r / min to 1000 r / min, and the mixing time is 10 min to 30 min.

[0037] In one embodiment, in step S2, the twin-screw extruder is set with a main extruder temperature of 160~170℃, a die temperature of 170~190℃, and a die head temperature of 190~210℃.

[0038] The above scheme, through component optimization, can produce PVC conduit with excellent impact and cold resistance.

[0039] The implementation schemes of the present invention will now be described in detail with reference to specific embodiments.

[0040] Example 1: A method for preparing an impact-resistant and cold-resistant polyvinyl chloride conduit, the method comprising the following steps: S1. By weight, add 100 parts of polyvinyl chloride resin, 12 parts of impact and cold-resistant additives, 3 parts of impact modifiers, 1 part of composite heat stabilizer, 8 parts of reinforcing filler, 1 part of polyvinyl alcohol, 2 parts of calcium stearate and 1 part of epoxidized soybean oil to a mixer and mix at 800 r / min for 25 min to obtain a mixture. The method for preparing the impact-resistant and cold-resistant additive is as follows: 10 parts by weight of butyl rubber are added to 18 parts of tetrahydrofuran, heated to 90°C, stirred at 300 r / min for 25 min, and then 0.5 parts of tert-butyl hydroperoxide, 2 parts of dioctyl sebacate and 2 parts of active silica are added, and the mixture is stirred and reacted for 2 h to obtain the impact-resistant and cold-resistant additive. The impact modifier is obtained by mixing ethylene-vinyl acetate copolymer and maleic anhydride-styrene graft copolymer in a mass ratio of 2:3; The composite heat stabilizer comprises a first heat stabilizer and a second heat stabilizer in a weight ratio of 3:2, wherein the first heat stabilizer is a calcium-zinc heat stabilizer and the second heat stabilizer is hydrotalcite. The method for preparing the reinforcing filler is as follows: 7 parts by weight of reinforcing fiber are added to an alcohol solution of 15 parts by weight of coupling agent (obtained by mixing n-octyltriethoxysilane, ethanol and water in a volume ratio of 4:3:3), heated to 60°C, stirred at 50 r / min for 2 h, filtered, washed and dried to obtain the reinforcing filler. The reinforcing fiber is obtained by mixing basalt fiber and glass fiber in a weight ratio of 4:3; wherein the basalt fiber has an average length of 20 μm and a diameter of 0.8 μm; and the glass fiber has an average length of 8 μm and a diameter of 0.5 μm. S2. The mixture is added to a twin-screw extruder for melting, extruded through a die, and the main machine temperature is set to 170°C, the die temperature to 185°C, and the die head temperature to 195°C. After cooling and sizing, an impact-resistant and cold-resistant polyvinyl chloride conduit is obtained.

[0041] Example 2: A method for preparing an impact-resistant and cold-resistant polyvinyl chloride conduit, the method comprising the following steps: S1. By weight, add 100 parts of polyvinyl chloride resin, 13 parts of impact and cold-resistant additives, 3 parts of impact modifiers, 1 part of composite heat stabilizer, 9 parts of reinforcing filler, 2 parts of polyvinyl alcohol, 2 parts of calcium stearate and 1 part of epoxidized soybean oil to a mixer and mix at a speed of 800 r / min for 25 min to obtain a mixture. The method for preparing the impact-resistant and cold-resistant additive is as follows: 10 parts by weight of butyl rubber are added to 20 parts of tetrahydrofuran, heated to 90°C, stirred at 300 r / min for 25 min, and then 0.6 parts of tert-butyl hydroperoxide, 2 parts of dioctyl sebacate and 2 parts of active silica are added, and the mixture is stirred and reacted for 2 h to obtain the impact-resistant and cold-resistant additive. The impact modifier is obtained by mixing ethylene-vinyl acetate copolymer and maleic anhydride-styrene graft copolymer in a mass ratio of 2:3; The composite heat stabilizer comprises a first heat stabilizer and a second heat stabilizer in a weight ratio of 3:2, wherein the first heat stabilizer is a calcium-zinc heat stabilizer and the second heat stabilizer is hydrotalcite. The method for preparing the reinforcing filler is as follows: 7 parts by weight of reinforcing fiber are added to an alcohol solution of 15 parts by weight of coupling agent (obtained by mixing n-octyltriethoxysilane, ethanol and water in a volume ratio of 4:3:3), heated to 60°C, stirred at 50 r / min for 2 h, filtered, washed and dried to obtain the reinforcing filler. The reinforcing fiber is obtained by mixing basalt fiber and glass fiber in a weight ratio of 4:3; wherein the basalt fiber has an average length of 20 μm and a diameter of 0.8 μm; and the glass fiber has an average length of 8 μm and a diameter of 0.5 μm. S2. The mixture is added to a twin-screw extruder for melting, extruded through a die, and the main machine temperature is set to 170°C, the die temperature to 190°C, and the die head temperature to 200°C. After cooling and sizing, an impact-resistant and cold-resistant polyvinyl chloride conduit is obtained.

[0042] Example 3: A method for preparing an impact-resistant and cold-resistant polyvinyl chloride conduit, the method comprising the following steps: S1. By weight, add 100 parts of polyvinyl chloride resin, 15 parts of impact and cold-resistant additive, 2 parts of impact modifier, 1.5 parts of composite heat stabilizer, 10 parts of reinforcing filler, 2 parts of polyvinyl alcohol, 2 parts of calcium stearate and 2 parts of epoxidized soybean oil to a mixer and mix at 800 r / min for 30 min to obtain a mixture; The method for preparing the impact-resistant and cold-resistant additive is as follows: 10 parts by weight of butyl rubber are added to 20 parts of tetrahydrofuran, heated to 90°C, stirred at 300 r / min for 25 min, and then 0.5 parts of tert-butyl hydroperoxide, 2 parts of dioctyl sebacate and 2 parts of active silica are added, and the mixture is stirred and reacted for 2 h to obtain the impact-resistant and cold-resistant additive. The impact modifier is obtained by mixing ethylene-vinyl acetate copolymer and maleic anhydride-styrene graft copolymer in a mass ratio of 2:3; The composite heat stabilizer comprises a first heat stabilizer and a second heat stabilizer in a weight ratio of 3:2, wherein the first heat stabilizer is a calcium-zinc heat stabilizer and the second heat stabilizer is hydrotalcite. The method for preparing the reinforcing filler is as follows: 7 parts by weight of reinforcing fiber are added to an alcohol solution of 15 parts by weight of coupling agent (obtained by mixing n-octyltriethoxysilane, ethanol and water in a volume ratio of 4:3:3), heated to 60°C, stirred at 50 r / min for 2 h, filtered, washed and dried to obtain the reinforcing filler. The reinforcing fiber is obtained by mixing basalt fiber and glass fiber in a weight ratio of 4:3; wherein the basalt fiber has an average length of 20 μm and a diameter of 0.8 μm; and the glass fiber has an average length of 8 μm and a diameter of 0.5 μm. S2. The mixture is added to a twin-screw extruder for melting, extruded through a die, and the main machine temperature is set to 170°C, the die temperature to 190°C, and the die head temperature to 200°C. After cooling and sizing, an impact-resistant and cold-resistant polyvinyl chloride conduit is obtained.

[0043] Comparative Example 1: The difference between Comparative Example 1 and Example 3 is that butyl rubber was directly replaced with impact and cold-resistant additives in Comparative Example 1, while the rest was the same as in Example 3.

[0044] Comparative Example 2: The difference between Comparative Example 2 and Example 3 is that the preparation method of the impact-resistant and cold-resistant additive in Comparative Example 2 is different, while the rest is the same as in Example 3. The preparation method of the impact-resistant and cold-resistant additive in Comparative Example 2 is as follows: 10 parts by weight of butyl rubber are added to 20 parts of tetrahydrofuran, heated to 90°C, stirred at 300 r / min for 25 min, then 0.5 parts of tert-butyl hydrogen peroxide and 2 parts of active silica are added, and the reaction is continued for 2 h to obtain the impact-resistant and cold-resistant additive.

[0045] Comparative Example 3: The difference between Comparative Example 3 and Example 3 is that the preparation method of the impact-resistant and cold-resistant additive in Comparative Example 3 is different, while the rest is the same as in Example 3. The preparation method of the impact-resistant and cold-resistant additive in Comparative Example 3 is as follows: 10 parts by weight of butyl rubber are added to 20 parts of tetrahydrofuran, heated to 90°C, stirred at 300 r / min for 25 min, then 0.5 parts of tert-butyl hydroperoxide and 2 parts of dioctyl sebacate are added, and the reaction is continued for 2 h to obtain the impact-resistant and cold-resistant additive.

[0046] Comparative Example 4: The difference between Comparative Example 4 and Example 3 is that no impact and cold-resistant additives were added in Comparative Example 4, but otherwise it was the same as Example 3.

[0047] Comparative Example 5: The difference between Comparative Example 5 and Example 3 is that no impact modifier was added in Comparative Example 5, but otherwise it is the same as Example 3.

[0048] Comparative Example 6: The difference between Comparative Example 6 and Example 3 is that the reinforcing filler in Comparative Example 6 is a single basalt fiber, and the average length of the basalt fiber is 20 μm and the diameter is 0.8 μm; otherwise, it is the same as Example 3.

[0049] Comparative Example 7: The difference between Comparative Example 7 and Example 3 is that the reinforcing filler in Comparative Example 7 is a single glass fiber, and the average length of the glass fiber is 8 μm and the diameter is 0.5 μm; otherwise, it is the same as Example 3.

[0050] The polyvinyl chloride (PVC) conduit samples prepared in Examples 1-3 and Comparative Examples 1-7 were subjected to performance tests. The tensile strength was tested according to GB / T 8804.2-1988; the impact performance was tested according to GB / T5836.1-2006, and the test was set at -15℃; the Vicat softening temperature was tested according to GB / T5836.1-2006. The results are shown in Table 1 below.

[0051] Table 1: Performance Test Results

[0052] As can be seen from the data analysis in Table 1, the present invention, by optimizing the composition of polyvinyl chloride pipe, has excellent application strength, significant impact resistance, and good cold and heat resistance stability. Compared to Example 3, Comparative Example 1 directly used butyl rubber. Unmodified butyl rubber has poor compatibility with PVC, resulting in limited toughening effect and overall performance inferior to Example 3. The preparation methods of the impact and cold-resistant additives in Comparative Examples 2 and 3 are different. Comparative Example 2 did not add dioctyl sebacate, which, as a low-temperature plasticizer, helps to lower the glass transition temperature of the material. Comparative Example 3 did not add active silica, resulting in an incomplete chain segment structure and a crosslinking network structure inferior to Example 3. Comparative Example 4 did not add impact and cold-resistant additives, and its performance decreased significantly, indicating that adding impact and cold-resistant additives in this invention can promote better performance. Comparative Example 5 did not add impact modifiers, and the elastomer toughening and interfacial compatibility were inferior to Example 3, thus resulting in performance inferior to Example 3. Comparative Examples 6 and 7 used single fibers as reinforcing fillers, respectively, and failed to construct a multi-layered reinforcing structure, indicating that adding basalt fibers and glass fibers of different specifications helps to obtain PVC pipes with better performance and thus better application value.

[0053] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0054] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An impact-resistant and cold-resistant polyvinyl chloride conduit, characterized in that, The polyvinyl chloride conduit comprises the following raw materials in parts by weight: 80-100 parts of polyvinyl chloride resin, 5-15 parts of impact and cold-resistant additives, 1-5 parts of impact modifiers, 0.2-5 parts of composite heat stabilizers, 8-15 parts of reinforcing fillers, 1-2 parts of dispersant, 0.5-3 parts of lubricant, and 0.5-2 parts of plasticizer.

2. The polyvinyl chloride conduit according to claim 1, characterized in that, The method for preparing the impact-resistant and cold-resistant additive is as follows: butyl rubber is added to tetrahydrofuran, heated to 85℃~100℃, stirred at a speed of 300r / min~500r / min for 20min~30min, then tert-butyl hydroperoxide, dioctyl sebacate and active silica are added, and the reaction is continued to be stirred for 1h~3h to obtain the impact-resistant and cold-resistant additive.

3. The polyvinyl chloride conduit according to claim 1, characterized in that, The impact modifier is obtained by mixing ethylene-vinyl acetate copolymer and maleic anhydride-styrene graft copolymer in a mass ratio of (1~3):(1~5).

4. The polyvinyl chloride conduit according to claim 1, characterized in that, The composite heat stabilizer includes a first heat stabilizer and a second heat stabilizer, wherein the first heat stabilizer is at least one of calcium-zinc heat stabilizer and organotin heat stabilizer; and the second heat stabilizer is at least one of stearoylbenzoylmethane and hydrotalcite.

5. The polyvinyl chloride conduit according to claim 1, characterized in that, The method for preparing the reinforcing filler is as follows: adding reinforcing fibers to an alcohol solution of coupling agent, heating to 55℃~60℃, stirring at a speed of 50r / min~100r / min for 1h~5h, filtering, washing, and drying to obtain the reinforcing filler.

6. The polyvinyl chloride conduit according to claim 5, characterized in that, The reinforcing fiber is a mixture of basalt fiber and glass fiber of different specifications; wherein the average length of the basalt fiber is 15~25μm and the diameter is 0.5~1.0μm; and the average length of the glass fiber is 3~8μm and the diameter is 0.5~1.0μm.

7. The polyvinyl chloride conduit according to claim 1, characterized in that, The dispersant is at least one of polyvinyl alcohol, polyvinyl acetate, and hydroxypropyl methylcellulose.

8. The polyvinyl chloride conduit according to claim 1, characterized in that, The lubricant is at least one of calcium stearate, pentaerythritol stearate, oxidized polyethylene wax, and ethylene bis-stearamide.

9. The polyvinyl chloride conduit according to claim 1, characterized in that, The plasticizer is at least one of epoxidized soybean oil and dioctyl terephthalate.

10. A method for preparing an impact-resistant and cold-resistant polyvinyl chloride conduit, characterized in that, The preparation method is used to prepare the impact-resistant and cold-resistant polyvinyl chloride conduit as described in any one of claims 1 to 9, and the preparation method includes the following steps: S1. Add polyvinyl chloride resin, impact and cold-resistant additives, impact modifiers, composite heat stabilizers, reinforcing fillers, dispersants, lubricants, and plasticizers to a mixer for mixing to obtain a mixture; S2. The mixture is added to a twin-screw extruder for melting, extruded through a die, cooled and sized to obtain an impact-resistant and cold-resistant polyvinyl chloride conduit.

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