High-performance PVC line pipe and injection molding method thereof

Abstract

The invention relates to the technical field of high polymer materials, and provides a high-performance PVC spool and an injection molding method thereof.The spool is prepared from, by weight, 100 parts of polyvinyl chloride resin; 5 to 10 parts of nano silicon dioxide; 1 to 5 parts of graphene; 2-4 parts of a heat stabilizer; 3-6 parts of an impact modifier; 0.5-1 part of an ultraviolet light absorber; 0.5 to 1 part of an antioxidant; 1-3 parts of a compatilizer; the nano silicon dioxide is surface-modified nano silicon dioxide, and the graphene is modified graphene. The surface-modified nano silicon dioxide, the modified graphene, the heat stabilizer, the impact modifier, the ultraviolet light absorber, the antioxidant and the compatilizer are mixed according to a specific proportion to prepare the PVC spool, and the problems that when the PVC spool is exposed to an ultraviolet, high-temperature or strong acid and alkali environment, aging is fast, the mechanical property is reduced, and the chemical resistance is insufficient are solved.

Description

Technical Field

[0001] The present application relates to the technical field of polymer materials, and in particular to a high-performance PVC wire pipe and an injection molding method thereof. Background Art

[0002] PVC (polyvinyl chloride) wire pipe is an important pipe widely used in construction, industry and power systems. Due to its excellent mechanical properties, corrosion resistance and insulation performance, PVC wire pipe plays an irreplaceable role in cable protection and wiring projects. However, with the increasing demand for modernization, PVC wire pipe needs to work under more complex environmental conditions, such as high temperature, high humidity, strong ultraviolet rays and other extreme environments. Therefore, further improving the performance of PVC wire pipe has become the focus of current industry research.

[0003] In the prior art, the conventional PVC wire pipe injection molding method generally includes the following steps: first, polyvinyl chloride resin is mixed with components such as plasticizer, heat stabilizer and filler in a certain proportion; then, the components are mixed by a high-speed mixer to evenly disperse the components; the mixture is melted and plasticized in a twin-screw extruder, and after sizing, cooling and pulling, it is injection molded into a wire pipe product that can meet the use requirements in general environments, such as having good insulation and certain mechanical strength.

[0004] Regarding the above technical solution, although the toughness and thermal stability of PVC wire pipes can be improved by adding plasticizers and heat stabilizers to the traditional formula, in actual applications, when PVC wire pipes are exposed to ultraviolet rays, high temperatures or strong acid and alkali environments, there are still problems such as rapid aging, decreased mechanical properties and insufficient chemical resistance. Summary of the invention

[0005] In order to improve the problems of rapid aging, decreased mechanical properties and insufficient chemical resistance of PVC wire pipes when exposed to ultraviolet rays, high temperature or strong acid and alkali environment, the present application provides a high-performance PVC wire pipe and an injection molding method thereof.

[0006] The invention provides a high-performance PVC wire pipe, which is made of the following components in parts by weight: 100 parts of polyvinyl chloride resin; 5-10 parts of nano-silicon dioxide; 1-5 parts of graphene; 2-4 parts of heat stabilizer; 3-6 parts of impact modifier; 0.5-1 part of ultraviolet absorber; 0.5-1 part of antioxidant; 1-3 parts of compatibilizer; the nano-silicon dioxide is surface-modified nano-silicon dioxide, and the graphene is modified graphene.

[0007] As a preferred embodiment, the nano-silica is surface treated with one selected from 3-aminopropyltriethoxysilane and vinyltriethoxysilane to obtain surface-modified nano-silica.

[0008] As a preferred embodiment, the graphene is coated and modified by one selected from polyethylene glycol and polyvinyl pyrrolidone to obtain modified graphene.

[0009] As a preferred embodiment, the heat stabilizer is selected from one or a combination of at least two of an organic tin heat stabilizer and a rare earth heat stabilizer.

[0010] As a preferred embodiment, the impact modifier is selected from chlorinated polyethylene, acrylic copolymer, and methyl methacrylate-butadiene-styrene copolymer.

[0011] As a preferred embodiment, the ultraviolet absorber is selected from one of UV-531, UV-327 and UV-329.

[0012] As a preferred embodiment, the antioxidant is selected from one or a combination of at least two of hindered phenol antioxidants and phosphite antioxidants.

[0013] As a preferred embodiment, the compatibilizer is selected from maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene, and ethylene-vinyl acetate copolymer.

[0014] The present application also provides an injection molding method for high-performance PVC wire pipes, which includes: adding the polyvinyl chloride resin, the surface-modified nano-silicon dioxide, the modified graphene, the heat stabilizer, the impact modifier, the ultraviolet absorber, the antioxidant and the compatibilizer to a high-speed mixer, mixing them under preset conditions to obtain a premix; adding the premix to a twin-screw extruder, melting them under preset process conditions, and extruding the molten material through a die to obtain a high-performance PVC wire pipe blank; passing the high-performance PVC wire pipe blank through a sizing sleeve, sizing and molding it under a vacuum degree of 0.02-0.05MPa, placing the molded high-performance PVC wire pipe blank into a cooling water tank, controlling the water temperature at 10-20°C, and fully cooling and curing it to obtain a cooled high-performance PVC wire pipe blank, continuously traction the cooled high-performance PVC wire pipe blank by a traction machine at a speed of 5-10m / min, and cutting it into the required length by a fixed-length cutting machine to obtain a high-performance PVC wire pipe.

[0015] As a preferred embodiment, the preset conditions are mixing for 8-12 minutes at a rotation speed of 1000-1500r / min and a temperature of 80-100°C; the preset temperature is 160-180°C; the preset process conditions are setting the temperature in the feeding zone of the extruder to 150-160°C, the temperature in the plasticizing zone to 160-170°C, the temperature in the homogenizing zone to 170-180°C, the temperature in the extrusion zone to 180-190°C, and the screw speed to 200-300r / min.

[0016] Compared with the prior art, the present application has the following beneficial effects: good performance and strong adaptability. The nano-silicon dioxide is surface modified to enhance its compatibility with the matrix polyvinyl chloride resin, and the graphene is surface functionalized to improve its dispersibility and enhance its performance. The surface-modified nano-silicon dioxide, modified graphene, heat stabilizer, impact modifier, UV absorber, antioxidant and compatibilizer are mixed in a specific proportion, and mixed by a high-speed mixer at a suitable temperature and speed to ensure that the raw materials are evenly dispersed. The mixture is passed through a twin-screw extruder, melt-plasticized under multi-stage temperature control conditions, and extruded through a die to form a PVC wire pipe blank. The wire pipe blank is sized in a vacuum environment through a sizing sleeve. The high-performance PVC wire pipe product is obtained by traction and cutting after cooling. By introducing surface-modified nano-silica and modified graphene, the high-performance PVC wire pipe has achieved comprehensive improvement in mechanical properties, thermal conductivity, chemical resistance and aging resistance. The synergistic effect of UV absorber and antioxidant effectively improves the UV resistance and aging resistance of the wire pipe, and solves the problem that traditional PVC wire pipe is prone to aging and failure under complex working conditions. It can widely adapt to various extreme environmental requirements and improve the problems of rapid aging, decreased mechanical properties and insufficient chemical resistance of PVC wire pipe when exposed to ultraviolet rays, high temperature or strong acid and alkali environment. DETAILED DESCRIPTION

[0017] The technical scheme of the present invention is further illustrated by specific examples below. Those skilled in the art should understand that the examples are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0018] Embodiment 1: A high-performance PVC wire tube, its components and injection molding method are as follows: Components (parts by weight): Polyvinyl chloride resin (PVC): 100 parts; Surface modified nano-silicon dioxide: 5 parts; Modified graphene: 2 parts; Organic tin heat stabilizer: 3 parts; Chlorinated polyethylene: 5 parts; UV-531: 0.8 parts; Hindered phenol antioxidant: 0.6 parts; Maleic anhydride grafted polyethylene: 2 parts.

[0019] Injection molding method: Surface modification of nano-silicon dioxide: The nano-silica was placed in an ethanol solution of 3-aminopropyltriethoxysilane (KH-550) at a ratio of 1:5 (mass ratio), and mechanically stirred at room temperature for 30 minutes to fully disperse it; then the dispersion was heated to 80°C for reflux reaction for 2 hours to promote the coupling agent to combine with the hydroxyl groups on the surface of the nano-silica; after the reaction, the product was filtered and washed with anhydrous ethanol for 3 times to remove the unreacted coupling agent; finally, the filtrate was dried in an oven at 120°C for 3 hours to obtain surface-modified nano-silica; Modification of graphene: Graphene was added to a 10% by mass polyethylene glycol (PEG-400) aqueous solution at a ratio of 1:10 (mass ratio), and ultrasonically dispersed at room temperature for 1 hour to uniformly disperse the graphene sheets; the dispersion was then stirred at 70°C for 4 hours to gradually adsorb and coat the polyethylene glycol molecules on the surface of the graphene sheets; after the reaction was completed, the product was filtered, washed with distilled water until neutral, and then the filtrate was vacuum dried at 80°C for 12 hours to obtain modified graphene.

[0020] Raw material mixing: Surface-modified nano-silica, modified graphene, PVC, organotin heat stabilizer, chlorinated polyethylene, UV-531, hindered phenol antioxidant and maleic anhydride grafted polyethylene were added into a high-speed mixer and mixed at a speed of 1200 r / min and a temperature of 90° C. for 10 minutes to obtain a uniform premix.

[0021] Melt Blending: The premix was fed into a twin-screw extruder for melt blending under the following temperature conditions: Feeding zone: 150℃; Plasticizing zone: 165℃; Homogenizing zone: 175℃; Extrusion zone: 185℃; The screw speed is 250r / min, and the wire tube billet is extruded.

[0022] Sizing and cooling: The wire tube blank is sized and formed by a sizing sleeve under a vacuum degree of 0.03MPa, and then enters a 10℃ cooling water tank for cooling and solidification. Finally, it is towed by a traction machine at a speed of 7m / min and cut into high-performance PVC wire tubes with a length of 2 meters.

[0023] Test results: The tensile strength of the wire tube of this embodiment is 32 MPa, the elongation at break is 310%, the flame retardancy is UL94V-0, the thermal conductivity is 0.42 W / m·K, the chemical resistance (strength retention rate after strong acid test) is 90%, and the aging resistance (strength retention rate after ultraviolet aging) is 92%.

[0024] Embodiment 2: A high-performance PVC conduit, the components of which are as follows: Polyvinyl chloride resin (PVC): 100 parts; Surface modified nano-silicon dioxide: 8 parts; Modified graphene: 4 parts; Rare earth heat stabilizer: 3 parts; Acrylate copolymer: 4 parts; UV-327: 0.7 parts; Phosphite antioxidant: 0.8 parts; Maleic anhydride grafted polypropylene: 2 parts.

[0025] Injection molding method: Surface modification of nano-silicon dioxide: Nano-silica was placed in an ethanol solution of 3-aminopropyltriethoxysilane (KH-550), and nano-silica and coupling agent were added at a mass ratio of 1:5; mechanical stirring was performed at room temperature for 40 minutes to ensure that the nano-silica was evenly dispersed; the mixture was then heated to 90°C and refluxed for 2 hours to allow the coupling agent molecules to bind to the surface of the nano-silica through chemical bonds. After the reaction, the product was filtered, washed with anhydrous ethanol 3 times to remove the residual coupling agent, and dried in an oven at 120°C for 4 hours to obtain surface-modified nano-silica.

[0026] Modification of graphene: Graphene was added to a 10% polyvinyl pyrrolidone (PVP) aqueous solution, and ultrasonic dispersion was performed at a mass ratio of 1:10 between graphene and solution for 1 hour to make the graphene sheets evenly suspended; the dispersion was then stirred and heated to 75°C for 4 hours, and the polyvinyl pyrrolidone molecules were gradually adsorbed and evenly coated on the graphene surface. After the reaction was completed, the solution was filtered, washed with deionized water, and vacuum dried for 12 hours to obtain modified graphene.

[0027] Raw material mixing: Surface-modified nano-silica, modified graphene, PVC, rare earth heat stabilizer, acrylic copolymer, UV-327, phosphite antioxidant and maleic anhydride grafted polypropylene were added into a high-speed mixer and mixed at a speed of 1300 r / min and a temperature of 95° C. for 8 minutes to obtain a uniform premix.

[0028] Melt Blending: The premix was fed into a twin-screw extruder for melt blending under the following temperature conditions: Feeding zone: 155℃; Plasticizing zone: 170℃; Homogenizing zone: 180℃; Extrusion zone: 190℃; The screw speed is 250r / min, and the wire tube billet is extruded.

[0029] Sizing and cooling: The wire tube blank is sized and formed by a sizing sleeve under a vacuum degree of 0.04MPa, and then enters a 10°C cooling water tank for cooling and solidification. Finally, it is towed by a traction machine at a speed of 8m / min and cut into high-performance PVC wire tubes with a length of 2 meters.

[0030] Test results: The tensile strength of the wire tube in this embodiment is 35 MPa, the elongation at break is 295%, the flame retardancy is UL94V-0, the thermal conductivity is 0.45 W / m·K, the chemical resistance (strength retention rate after strong acid test) is 93%, and the aging resistance (strength retention rate after ultraviolet aging) is 88%.

[0031] Embodiment 3: A high-performance PVC conduit, the components are as follows: Polyvinyl chloride resin (PVC): 100 parts; Surface modified nano-silicon dioxide: 10 parts; Modified graphene: 5 parts; Mixed heat stabilizer (a mixture of organic tin heat stabilizer and rare earth heat stabilizer in a ratio of 1:1): 4 parts; Methyl methacrylate-butadiene-styrene copolymer (MBS): 6 parts; UV-329: 0.6 parts; Mixed antioxidant (a mixture of hindered phenol antioxidant and phosphite antioxidant in a ratio of 1:1): 1 part; Ethylene-vinyl acetate copolymer: 3 parts.

[0032] Injection molding method: Surface modification of nano-silicon dioxide: Nano-silica was added to a methanol solution of vinyl triethoxysilane (KH-570) at a mass ratio of 1:6, stirred evenly, and allowed to stand at room temperature for 30 minutes; the mixture was then heated to 75°C and kept under reflux for 3 hours to allow the coupling agent to bond to the surface of the nano-silica to form a silicon-oxygen bond. After the reaction was completed, the mixture was filtered, washed with anhydrous methanol, dried, and further dried in an oven at 110°C for 2 hours to obtain surface-modified nano-silica.

[0033] Modification of graphene: Graphene was added to a 15% polyethylene glycol (PEG-400) solution at a mass ratio of 1:8; ultrasonic treatment was performed in an ultrasonic processor for 60 minutes to ensure that the graphene was fully dispersed; the solution was then heated to 80°C and mechanically stirred for 5 hours to allow the polyethylene glycol molecules to coat the surface of the graphene sheet. After the reaction was completed, the product was filtered, washed with distilled water 3 times, and finally vacuum dried at 80°C for 24 hours to obtain modified graphene.

[0034] Raw material mixing: Surface-modified nano-silica, modified graphene, PVC, mixed heat stabilizer, MBS, UV-329, mixed antioxidant, and ethylene-vinyl acetate copolymer were added into a high-speed mixer and mixed at a speed of 1300 r / min and a temperature of 95° C. for 12 minutes to obtain a uniform premix.

[0035] Melt Blending: The premix was fed into a twin-screw extruder for melt blending under the following temperature conditions: Feeding zone: 155℃; Plasticizing zone: 170℃; Homogenizing zone: 180℃; Extrusion zone: 190℃; The screw speed is 250r / min, and the wire tube billet is extruded.

[0036] Sizing and cooling: The wire tube blank is sized and formed by a sizing sleeve under a vacuum degree of 0.04MPa, and then enters a 10℃ cooling water tank for cooling and solidification. Finally, it is towed by a traction machine at a speed of 9m / min and cut into high-performance PVC wire tubes with a length of 2 meters.

[0037] Test results: The tensile strength of the wire tube in this embodiment is 37 MPa, the elongation at break is 320%, the flame retardancy reaches UL94V-0 level, the thermal conductivity is 0.47 W / m·K, the chemical resistance (strength retention rate after strong acid test) is 95%, and the aging resistance (strength retention rate after ultraviolet aging) is 90%.

[0038] Embodiment 4: A high-performance PVC wire tube, its components and injection molding method are as follows: Components (parts by weight): Polyvinyl chloride resin (PVC): 100 parts; Surface modified nano-silicon dioxide: 7 parts; Modified graphene: 3 parts; Rare earth heat stabilizer: 3 parts; Acrylate copolymer: 6 parts; UV-329: 0.6 parts; Mixed antioxidant (a mixture of hindered phenol antioxidant and phosphite antioxidant in a ratio of 1:1): 1.2 parts; Ethylene-vinyl acetate copolymer: 2 parts.

[0039] Injection molding method: Surface modification of nano-silicon dioxide: Nano-silica was added to an ethanol solution of vinyltriethoxysilane (KH-570) at a mass ratio of 1:5, stirred at room temperature for 30 minutes, and then heated to 85°C for reflux reaction for 3 hours; after the reaction was completed, the mixed solution was filtered and washed with anhydrous ethanol for 3 times to remove unreacted products; finally, it was dried in a vacuum drying oven at 110°C for 3 hours to obtain surface-modified nano-silica.

[0040] Modification of graphene: Graphene was added to a 10% polyvinyl pyrrolidone (PVP) solution at a mass ratio of 1:12, and stirred evenly; then ultrasonic dispersion was performed in an ultrasonic cleaner for 1.5 hours to make the graphene evenly distributed; after the ultrasonication, the dispersion was heated to 80°C and stirred for 4 hours, and the polyvinyl pyrrolidone molecules were gradually coated on the surface of the graphene sheet. The solution was filtered, washed with deionized water, and dried in a vacuum drying oven for 12 hours to obtain modified graphene.

[0041] Raw material mixing: Surface-modified nano-silica, modified graphene, PVC, rare earth heat stabilizer, acrylic copolymer, UV-329, mixed antioxidant, and ethylene-vinyl acetate copolymer were added into a high-speed mixer and mixed at a speed of 1400 r / min and a temperature of 85° C. for 10 minutes to obtain a uniform premix.

[0042] Melt Blending: The premix was fed into a twin-screw extruder for melt blending under the following temperature conditions: Feeding zone: 155℃; Plasticizing zone: 170℃; Homogenizing zone: 180℃; Extrusion zone: 190℃; The screw speed is 280r / min, and the wire tube billet is extruded.

[0043] Sizing and cooling: The wire tube blank is sized and formed by a sizing sleeve under a vacuum degree of 0.025MPa, and then enters a 15°C cooling water tank for cooling and solidification. Finally, it is towed by a traction machine at a speed of 8m / min and cut into high-performance PVC wire tubes with a length of 2 meters.

[0044] Test results: The tensile strength of the wire tube in this embodiment is 34 MPa, the elongation at break is 305%, the flame retardancy reaches UL94V-0 level, the thermal conductivity is 0.44 W / m·K, the chemical resistance (strength retention rate after strong alkali test) is 92%, and the aging resistance (strength retention rate after ultraviolet aging) is 89%.

[0045] Comparative Example 1: The formula and method are the same as those in Example 1, but no surface-modified nano-silicon dioxide is added.

[0046] Test results: The tensile strength dropped to 20MPa, the elongation at break dropped to 180%, the flame retardancy had no grade, the thermal conductivity dropped to 0.30W / m·K, the chemical resistance (strength retention after strong acid test) dropped to 70%, and the aging resistance (strength retention after UV aging) dropped to 50%.

[0047] Comparative Example 2: The formula and method are the same as those in Example 1, but without adding modified graphene.

[0048] Test results: The tensile strength dropped to 25MPa, the elongation at break dropped to 210%, the flame retardancy only reached UL94V-2 level, the thermal conductivity dropped to 0.35W / m·K, the chemical resistance (strength retention rate after strong acid test) dropped to 75%, and the aging resistance (strength retention rate after UV aging) dropped to 60%.

[0049] Comparative Example 3: The formulation and method are the same as in Example 1, but without adding the impact modifier.

[0050] Test results: The tensile strength dropped to 22MPa, the elongation at break dropped to 190%, the flame retardancy only reached UL94V-2 level, the thermal conductivity dropped to 0.32W / m·K, the chemical resistance (strength retention rate after strong alkali test) dropped to 72%, and the aging resistance (strength retention rate after UV aging) dropped to 55%.

[0051] Comparative Example 4: The formulation and method are the same as in Example 1, but without adding the ultraviolet absorber.

[0052] Test results: The tensile strength dropped to 28MPa, the elongation at break dropped to 240%, the flame retardancy dropped to UL94V-2, the thermal conductivity dropped to 0.33W / m·K, the chemical resistance (strength retention after strong alkali test) dropped to 80%, and the aging resistance (strength retention after UV aging) dropped to 55%.

[0053] Comparative Example 5: The formulation and method are the same as in Example 1, but without adding the ultraviolet absorber.

[0054] Test results: The tensile strength dropped to 25MPa, the elongation at break dropped to 210%, the flame retardancy dropped to UL94V-2, the thermal conductivity dropped to 0.35W / m·K, the chemical resistance (strength retention after strong acid test) dropped to 75%, and the aging resistance (strength retention after UV aging) dropped to 60%.

[0055] Comparative Example 6: The formulation and method are the same as in Example 1, but no antioxidant is added.

[0056] Test results: The tensile strength dropped to 29MPa, the elongation at break dropped to 220%, the flame retardancy dropped to UL94V-2, the thermal conductivity dropped to 0.37W / m·K, the chemical resistance (strength retention after strong acid test) dropped to 78%, and the aging resistance (strength retention after UV aging) dropped to 50%.

[0057] The high performance PVC conduits of Examples 1-4 and Comparative Examples 1-6 were tested for performance, and the results are shown in Table 1 below: Table 1: Test result analysis: Embodiment performance advantages: Examples 1 to 4 exhibit excellent comprehensive properties, especially high thermal conductivity (up to 0.47 W / m·K) and chemical resistance (up to 95% strength retention).

[0058] The strength retention (90%) after UV aging demonstrates the synergistic effect of modified graphene, antioxidants, and UV absorbers.

[0059] Comparative analysis: Comparative Example 1: The absence of nano-silica significantly reduced the tensile strength and flame retardancy, demonstrating its key role in improving the overall performance of the material.

[0060] Comparative Example 4: The absence of the UV absorber resulted in a significant decrease in the aging resistance, which was only 55%, indicating the importance of the UV absorber in anti-UV aging.

[0061] Comparative Example 5: The absence of modified graphene reduces the thermal conductivity to 0.35 W / m·K, and the thermal management performance of the material is significantly reduced.

[0062] Comparative Example 6: The absence of antioxidant has a significant impact on chemical resistance and aging resistance, indicating its importance in resisting thermal oxidative degradation.

[0063] Comprehensive comparison: The significant performance difference between the examples and the comparative examples clearly demonstrates the synergistic effect of the components in the formulation of the present invention. In particular, the introduction of nano-silicon dioxide and modified graphene plays a key role in improving tensile strength, thermal conductivity, chemical resistance and aging resistance.

[0064] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A high-performance PVC conduit, characterized in that: The wire tube is made of the following components in parts by weight, including: 100 parts of polyvinyl chloride resin; 5-10 parts of nano silicon dioxide; 1-5 parts of graphene; 2-4 parts of heat stabilizer; 3-6 parts of impact modifier; 0.5-1 part of ultraviolet absorber; 0.5-1 part of antioxidant; 1-3 parts of compatibilizer; The nano silicon dioxide is surface-modified nano silicon dioxide, and the graphene is modified graphene.

2. The high-performance PVC conduit according to claim 1, characterized in that: The nano-silica is surface treated with one selected from 3-aminopropyltriethoxysilane and vinyltriethoxysilane to obtain surface-modified nano-silica.

3. The high performance PVC conduit according to claim 1, characterized in that: The graphene is coated and modified by one selected from polyethylene glycol and polyvinyl pyrrolidone to obtain modified graphene.

4. The high performance PVC conduit according to claim 1, characterized in that: The heat stabilizer is selected from one of an organic tin heat stabilizer and a rare earth heat stabilizer, or a combination of at least two of them.

5. The high performance PVC conduit according to claim 1, characterized in that: The impact modifier is selected from chlorinated polyethylene, acrylic copolymer, and methyl methacrylate-butadiene-styrene copolymer.

6. The high performance PVC conduit according to claim 1, characterized in that: The ultraviolet absorber is selected from one of UV-531, UV-327 and UV-329.

7. The high performance PVC conduit according to claim 1, characterized in that: The antioxidant is selected from one of hindered phenol antioxidants and phosphite antioxidants or a combination of at least two thereof.

8. The high performance PVC conduit according to claim 1, characterized in that: The compatibilizer is selected from maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene, and ethylene-vinyl acetate copolymer.

9. An injection molding method for high-performance PVC wire pipe according to claims 1-8, characterized in that: The injection molding method comprises: Adding the polyvinyl chloride resin, the surface-modified nano-silica, the modified graphene, the heat stabilizer, the impact modifier, the ultraviolet absorber, the antioxidant and the compatibilizer into a high-speed mixer, and mixing them under preset conditions to obtain a premix; The premix is ​​added into a twin-screw extruder, melted under preset process conditions, and the molten material is extruded through a die to obtain a high-performance PVC wire pipe blank; The high-performance PVC wire pipe blank is passed through a sizing sleeve and sizing-molded under a vacuum degree of 0.02-0.05MPa. The molded high-performance PVC wire pipe blank is placed in a cooling water tank with the water temperature controlled at 10-20°C for sufficient cooling and curing to obtain a cooled high-performance PVC wire pipe blank. The cooled high-performance PVC wire pipe blank is continuously pulled by a traction machine at a speed of 5-10m / min and cut into the required length by a fixed-length cutting machine to obtain a high-performance PVC wire pipe.

10. The injection molding method according to claim 9, characterized in that: The preset conditions are mixing for 8-12 minutes at a rotation speed of 1000-1500 r / min and a temperature of 80-100° C.; the preset temperature is 160-180° C.; The preset process conditions are as follows: the temperature of the feeding zone of the extruder is set at 150-160°C, the temperature of the plasticizing zone is set at 160-170°C, the temperature of the homogenizing zone is set at 170-180°C, the temperature of the extrusion zone is set at 180-190°C, and the screw speed is set at 200-300r / min.

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