High-thermal-conductivity anti-aging PE (polyethylene) pipe as well as preparation method and application thereof

Abstract

The invention relates to the technical field of high polymer materials, in particular to a high-thermal-conductivity anti-aging PE pipe as well as a preparation method and application thereof. The high-thermal-conductivity anti-aging PE pipe provided by the invention is prepared from the following raw materials in parts by weight: 100 parts of polyethylene, 20-35 parts of fluorine modified nanofiller, 8-15 parts of a composite anti-aging agent, 10-20 parts of far infrared fibers, 2-4 parts of a lubricant, 0.5-2 parts of a dispersant and 0.4-1 part of a plasticizer, wherein the fluorine-modified nano filler is prepared from fluorine-modified carbon nanotubes, fluorine-modified graphene and fluorine-modified nano aluminum oxide in a mass ratio of 1: (2-3): (1-2). The PE pipe provided by the invention has high thermal conductivity, good aging resistance and good mechanical properties, not only can meet the performance requirements of a ground source heat pump system on the PE pipe, but also greatly prolongs the service life of the PE pipe, and reduces the maintenance cost of the ground source heat pump system.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a high thermal conductivity and anti-aging PE pipe, its preparation method and application. Background Technology

[0002] With the increasing severity of the global energy crisis and environmental pollution, the search for and utilization of renewable energy has become an urgent priority. Ground source heat pumps, as a highly efficient and environmentally friendly air conditioning system that utilizes shallow geothermal resources, have attracted widespread attention due to their high efficiency, energy saving, and environmental friendliness. PE (polyethylene) pipes, due to their corrosion resistance, wear resistance, and long service life, are widely used as buried pipe materials in ground source heat pump systems.

[0003] However, while traditional PE pipes possess good corrosion resistance and flexibility, their limited thermal conductivity makes them unsuitable for efficiently transferring underground heat. Furthermore, PE pipes buried underground for extended periods are exposed to factors such as microorganisms, moisture, and chemical corrosion in the soil, leading to aging and impacting the overall performance and lifespan of the system. Therefore, improving the thermal conductivity and anti-aging properties of PE pipes for ground source heat pumps is a pressing issue. While existing research on improving PE pipe performance is extensive, it largely focuses on optimizing single properties, failing to achieve a synergistic improvement in both thermal conductivity and anti-aging properties. Existing technologies utilize graphene-carbon fiber composite thermally conductive fillers to enhance the thermal conductivity of PE pipes, but these lack an anti-aging system designed for the complex underground environment, making them prone to aging failure during long-term service. Other existing technologies employ a combination of amine and phenolic antioxidants to improve the anti-aging properties of PE materials, but this does not improve thermal conductivity, still failing to meet the high-efficiency heat exchange requirements of ground source heat pump systems. In addition, when improving the performance of PE pipes by adding inorganic fillers, there are problems such as poor dispersion of inorganic fillers in polyethylene and poor compatibility with PE matrix, which leads to a decrease in the mechanical properties of the resulting pipes.

[0004] Therefore, there is an urgent need to develop a PE pipe that combines high thermal conductivity and anti-aging properties with good mechanical properties to adapt to the special service environment of ground source heat pump buried pipes. Summary of the Invention

[0005] In view of this, the present invention provides a high thermal conductivity and anti-aging PE pipe, its preparation method and application. The PE pipe has high thermal conductivity and good aging resistance, as well as good mechanical properties, which greatly extends the service life of traditional PE pipes and reduces the maintenance cost of ground source heat pump systems.

[0006] To solve the above technical problems, the first aspect of the present invention provides a high thermal conductivity and anti-aging PE pipe, which is made of the following raw materials in parts by weight: 100 parts of polyethylene, 20-35 parts of fluorine-modified nanofiller, 8-15 parts of composite anti-aging agent, 10-20 parts of far-infrared fiber, 2-4 parts of lubricant, 0.5-2 parts of dispersant and 0.4-1 parts of plasticizer; The fluorine-modified nanofiller is composed of fluorine-modified carbon nanotubes, fluorine-modified graphene, and fluorine-modified nano-alumina in a mass ratio of 1:2-3:1-2.

[0007] The high thermal conductivity and anti-aging PE pipe provided by this invention uses polyethylene as the matrix and employs fluorine-modified nanofillers modified with ammonium fluorozirconate. Ammonium fluorozirconate can dissociate into fluorozirconate ions in water, which further hydrolyze into zirconium-containing active substances. These active substances readily combine with active groups such as hydroxyl groups on the surfaces of carbon nanotubes, graphene, and nano-alumina to form an inorganic coating layer. Fluorine ions remain on the surface of the coating layer, forming a fluorine-containing surface-modified layer. The extremely low surface energy of fluorine is utilized to reduce the surface energy of the nanofillers, preventing agglomeration. Furthermore, the fluorine-containing surface-modified layer also improves the compatibility between the nanofillers and polyethylene, making the nanofillers easier and more uniformly dispersed in the polyethylene matrix, thereby effectively improving the thermal conductivity of polyethylene. Secondly, this invention also adds a composite anti-aging agent and far-infrared fibers. The composite anti-aging agent improves the aging resistance and antimicrobial decomposition ability of polyethylene, while the addition of far-infrared fibers not only improves the heat transfer effect of polyethylene fibers but also compensates for the decrease in the mechanical properties of polyethylene caused by the addition of inorganic nanofillers. By combining fluorine-modified nanofillers, composite anti-aging agents, and far-infrared fibers, polyethylene pipes with high thermal conductivity, aging resistance, and good mechanical properties were successfully obtained.

[0008] Fluorine-modified carbon nanotubes, fluorine-modified graphene, and fluorine-modified nano-alumina were used as fluorine-modified nanofillers, which can form a "point-line-surface" structure inside the PE matrix, ensuring an effective improvement in the thermal conductivity of PE pipes.

[0009] In conjunction with the first aspect, the preparation method of the fluorine-modified nanofiller is as follows: the carbon nanotubes, graphene and nano alumina are dispersed in water to obtain a suspension, the temperature is raised to 60-70℃, ammonium fluorozirconate is added to each, the pH is adjusted to 2-4 with phosphoric acid, the reaction is stirred for 5-10 hours, and then solid-liquid separation, washing and drying are performed to obtain fluorine-modified carbon nanotubes, fluorine-modified graphene and fluorine-modified nano alumina.

[0010] In conjunction with the first aspect, each gram of the carbon nanotubes, graphene, and nano-alumina is dispersed in 50-100 ml of water, and the mass ratios of the carbon nanotubes, graphene, and nano-alumina to ammonium fluorozirconate are respectively 1:3-4, 1:2.5-3.5, and 1:2-3.

[0011] In conjunction with the first aspect, the composite anti-aging agent is composed of hyperbranched amine anti-aging agents, microbial inhibitors, and nano-calcium carbonate in a mass ratio of 4-6:2-3:1.

[0012] In conjunction with the first aspect, the hyperbranched amine antioxidant is a hyperbranched polyether amine or a hyperbranched polyurethane amine; the microbial inhibitor is 2-methyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, or dodecyl dimethyl benzyl ammonium bromide.

[0013] Hyperbranched amine antioxidants have excellent thermo-oxidative aging inhibition effects, and the introduction of hyperbranched structures can reduce the internal migration of antioxidants, thereby improving the stability and durability of anti-aging. Microbial inhibitors can inhibit the erosion and decomposition of PE materials by microorganisms in the soil, thereby extending the underground service life of PE pipes. Nano-calcium carbonate itself has excellent thermal stability, and its addition in small amounts will not affect the performance of PE pipes, but can also play a role in continuously adsorbing free radicals generated during aging, thereby helping to delay the thermo-oxidative aging of PE materials and achieving a synergistic anti-aging effect.

[0014] In conjunction with the first aspect, the lubricant is selected from at least one of butyl stearate, octyl stearate, and glyceryl stearate; the dispersant is polyethylene wax or polypropylene; and the plasticizer is liquid paraffin or microcrystalline wax.

[0015] In conjunction with the first aspect, the far-infrared fiber has a length of 4-10 μm and an aspect ratio of 30-50:1.

[0016] In conjunction with the first aspect, the carbon nanotube has an outer diameter of 10-20 nm and a tube length of 1-5 μm.

[0017] This invention also provides a method for preparing the above-mentioned high thermal conductivity and anti-aging PE pipe, the steps of which include: Polyethylene, fluorine-modified nanofillers, composite anti-aging agents and far-infrared fibers are heated and premixed in a high-speed mixer, and then lubricant, dispersant and plasticizer are added and mixed evenly to obtain a premixed material. The premixed material is added to a twin-screw extruder for heating and extrusion granulation to obtain modified PE granules; The modified PE granules are added to a single screw, and after extrusion molding, cooling and shaping, and traction winding, a high thermal conductivity and anti-aging PE pipe is obtained.

[0018] In conjunction with the second aspect, the temperature during the heating and premixing process is 90-100℃.

[0019] In conjunction with the second aspect, the temperature during heating and extrusion granulation is 150-220℃.

[0020] The present invention also provides an application of the above-mentioned high thermal conductivity and anti-aging PE pipe in ground source heat pump systems and buried equipment.

[0021] The beneficial effects of this invention are as follows: The improved high thermal conductivity and anti-aging PE pipe of this invention simultaneously possesses excellent thermal conductivity, aging resistance, and mechanical properties. Its thermal conductivity can reach over 3.0 W / m·K, oxidation induction time is nearly 30 minutes, and elongation at break exceeds 400%, demonstrating excellent overall performance. It is particularly suitable for the special service environment of buried pipes in ground source heat pumps. Furthermore, this PE pipe can be manufactured using conventional equipment, eliminating the need for new production equipment and effectively controlling production costs. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the following detailed embodiments are provided. For example, the present invention will be described in further detail. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0023] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the meaning consistent with their meaning in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined.

[0024] Currently, PE ground source heat pump pipes have relatively low thermal conductivity. PE pipes buried underground for a long time are affected by factors such as microorganisms, moisture and chemical corrosion in the soil, which leads to aging, increasing maintenance costs and risks to safe use.

[0025] In view of this, the present invention provides a high thermal conductivity and anti-aging PE pipe, which has the characteristics of high thermal conductivity, good anti-aging performance and excellent mechanical properties, ensuring the efficient operation of the ground source heat pump system, effectively improving the heat exchange efficiency and service life of the ground source heat pump system, and providing strong support for the widespread application and sustainable development of ground source heat pump technology.

[0026] Another objective of this invention is to provide a method for preparing the above-mentioned high thermal conductivity and anti-aging PE pipe. This method is simple, highly controllable, and moderately cost-effective. It is compatible with existing PE pipe production equipment and suitable for industrial mass production.

[0027] Another objective of this invention is to provide the application of the above-mentioned high thermal conductivity and anti-aging PE pipe in ground source heat pump systems and underground equipment. This PE pipe can directly replace traditional PE pipes, solving the problems of low thermal conductivity and easy aging of existing underground pipes after a certain number of years of use.

[0028] The following specific embodiments illustrate the PE pipe and its preparation method provided by the present invention.

[0029] The raw materials, reagents, and equipment used in this invention are all conventional commercially available reagents and equipment.

[0030] The preparation method of the fluorine-modified nanofiller used in the following embodiments of the present invention is as follows: 20-30g of carbon nanotubes, 20-30g of graphene and 20-30g of nano-alumina are dispersed in water to obtain suspensions. After heating to 60-75℃, ammonium fluorozirconate is added in sequence at mass ratios of 1:3-4, 1:2.5-3.5 and 1:2-3. The pH is adjusted to 2-4 with phosphoric acid. After stirring and reacting for 8-10h, solid-liquid separation, washing and drying are performed to obtain fluorine-modified carbon nanotubes, fluorine-modified graphene and fluorine-modified nano-alumina.

[0031] The carbon nanotubes used have an outer diameter of 10-20 nm and a tube length of 1-5 μm.

[0032] Example 1 This embodiment provides a high thermal conductivity and anti-aging PE pipe, which is made from the following raw materials in parts by weight: 100 parts high-density polyethylene, 28 parts fluorine-modified nanofillers (6 parts fluorine-modified carbon nanotubes, 15 parts fluorine-modified graphene, and 7 parts fluorine-modified nano alumina), 12 parts composite anti-aging agent (6 parts hyperbranched polyetheramine, 3 parts 2-methyl-4-isothiazolin-3-one, and 3 parts nano calcium carbonate), 15 parts far-infrared fiber (4-10 μm in length and 30-40:1 aspect ratio), 3 parts butyl stearate, 1 part polyethylene wax, and 0.6 parts microcrystalline wax.

[0033] The preparation method of this high thermal conductivity and anti-aging PE pipe is as follows: Polyethylene, fluorine-modified nanofiller, composite anti-aging agent and far-infrared fiber are added to a high-speed mixer and premixed at 90-100℃ for 30 minutes. Then, butyl stearate, polyethylene wax and microcrystalline wax are added and mixed evenly to obtain the premixed material.

[0034] The premixed material is added to a twin-screw extruder for heating and extrusion granulation to obtain modified PE granules. The temperatures of the feeding section, compression section, and melting section are 150-160℃, 180-190℃, and 210-220℃, respectively, and the screw speed is 80-100 rpm.

[0035] The modified PE granules obtained are added to a single screw, and after extrusion molding, cooling and shaping and traction winding, high thermal conductivity and anti-aging PE pipe is obtained.

[0036] Example 2 This embodiment provides a high thermal conductivity and anti-aging PE pipe, which is made from the following raw materials in parts by weight: 100 parts high-density polyethylene, 20 parts fluorine-modified nanofiller (4 parts fluorine-modified carbon nanotubes, 12 parts fluorine-modified graphene and 4 parts fluorine-modified nano alumina), 15 parts composite anti-aging agent (9 parts hyperbranched polyurethane amine, 3 parts dodecyl dimethyl benzyl ammonium bromide and 3 parts nano calcium carbonate), 20 parts far-infrared fiber (4-10 μm in length and 40-50:1 aspect ratio), 4 parts octyl stearate, 0.8 parts polypropylene (molecular weight 2000-3000) and 0.6 parts microcrystalline wax.

[0037] The preparation method of this high thermal conductivity and anti-aging PE pipe is as follows: Polyethylene, fluorine-modified nanofiller, composite anti-aging agent and far-infrared fiber are added to a high-speed mixer and premixed at 90-100℃ for 30 minutes. Then, octyl stearate, polypropylene and microcrystalline wax are added and mixed evenly to obtain the premixed material.

[0038] The premixed material is added to a twin-screw extruder for heating and extrusion granulation to obtain modified PE granules. The temperatures of the feeding section, compression section, and melting section are 150-160℃, 180-190℃, and 210-220℃, respectively, and the screw speed is 80-100 rpm.

[0039] The modified PE granules obtained are added to a single screw, and after extrusion molding, cooling and shaping and traction winding, high thermal conductivity and anti-aging PE pipe is obtained.

[0040] Example 3 This embodiment provides a high thermal conductivity and anti-aging PE pipe, which is made from the following raw materials in parts by weight: 100 parts high-density polyethylene, 35 parts fluorine-modified nanofillers (8 parts fluorine-modified carbon nanotubes, 18 parts fluorine-modified graphene, and 9 parts fluorine-modified nano alumina), 8 parts composite anti-aging agent (4 parts hyperbranched polyetheramine, 2 parts 5-chloro-2-methyl-4-isothiazolin-3-one, and 2 parts nano calcium carbonate), 10 parts far-infrared fiber (4-10 μm in length and 40-50:1 aspect ratio), 2 parts glyceryl stearate, 2 parts polyethylene wax, and 1 part microcrystalline wax.

[0041] The preparation method of this high thermal conductivity and anti-aging PE pipe is as follows: Polyethylene, fluorine-modified nanofiller, composite anti-aging agent and far-infrared fiber are added to a high-speed mixer and premixed at 90-100℃ for 30 minutes. Then, octyl stearate, polypropylene and microcrystalline wax are added and mixed evenly to obtain the premixed material.

[0042] The premixed material is added to a twin-screw extruder for heating and extrusion granulation to obtain modified PE granules. The temperatures of the feeding section, compression section, and melting section are 150-160℃, 180-190℃, and 210-220℃, respectively, and the screw speed is 80-100 rpm.

[0043] The modified PE granules obtained are added to a single screw, and after extrusion molding, cooling and shaping and traction winding, high thermal conductivity and anti-aging PE pipe is obtained.

[0044] Example 4 This embodiment provides a high thermal conductivity and anti-aging PE pipe, which is made from the following raw materials in parts by weight: 100 parts high-density polyethylene, 30 parts fluorine-modified nanofillers (6 parts fluorine-modified carbon nanotubes, 12 parts fluorine-modified graphene, and 12 parts fluorine-modified nano-alumina), 10 parts composite anti-aging agent (5 parts hyperbranched polyetheramine, 2.5 parts 5-chloro-2-methyl-4-isothiazolin-3-one, and 2.5 parts nano-calcium carbonate, respectively), 12 parts far-infrared fiber (4-10 μm in length and 30-50:1 aspect ratio), 2.5 parts glyceryl stearate, 1.5 parts polyethylene wax, and 1 part microcrystalline wax.

[0045] The preparation method of this high thermal conductivity and anti-aging PE pipe is as follows: Polyethylene, fluorine-modified nanofiller, composite anti-aging agent and far-infrared fiber are added to a high-speed mixer and premixed at 90-100℃ for 30 minutes. Then, octyl stearate, polypropylene and microcrystalline wax are added and mixed evenly to obtain the premixed material.

[0046] The premixed material is added to a twin-screw extruder for heating and extrusion granulation to obtain modified PE granules. The temperatures of the feeding section, compression section, and melting section are 150-160℃, 180-190℃, and 210-220℃, respectively, and the screw speed is 80-100 rpm.

[0047] The modified PE granules obtained are added to a single screw, and after extrusion molding, cooling and shaping and traction winding, high thermal conductivity and anti-aging PE pipe is obtained.

[0048] Comparative Example 1 This comparative example provides a high thermal conductivity and anti-aging PE pipe, made from the following raw materials in parts by weight: 100 parts high-density polyethylene, 28 parts organosilicon-modified nanofillers (6 parts organosilicon-modified carbon nanotubes, 15 parts organosilicon-modified graphene, and 7 parts organosilicon-modified nano alumina), 12 parts composite anti-aging agent (6 parts hyperbranched polyetheramine, 3 parts 2-methyl-4-isothiazolin-3-one, and 3 parts nano calcium carbonate), 15 parts far-infrared fiber (4-10 μm in length and 30-40:1 aspect ratio), 3 parts butyl stearate, 1 part polyethylene wax, and 0.6 parts microcrystalline wax.

[0049] The difference between this comparative example and Example 1 is that the fluorine-modified nanofiller is replaced with an equal amount of organosilicon-modified nanofiller. The preparation method of this high thermal conductivity and anti-aging PE pipe is the same as that in Example 1.

[0050] The preparation method of organosilicon-modified nanofillers is as follows: 20-30g of carbon nanotubes (outer diameter 10-20nm, tube length 1-5μm), 20-30g of graphene, and 20-30g of nano-alumina were dispersed in 1000-3000ml of water to obtain suspensions. After heating to 70-75℃, silane coupling agent KH570 was added sequentially at mass ratios of 1:3-4, 1:2.5-3.5, and 1:2-3. The pH was adjusted to 2-4 with phosphoric acid. After stirring and reacting for 8-10h, solid-liquid separation, washing, and drying were performed to obtain fluorinated carbon nanotubes, fluorinated graphene, and fluorinated nano-alumina.

[0051] Comparative Example 2 This comparative example provides a high thermal conductivity and anti-aging PE pipe. Its raw material composition is similar to that in Example 1. The only difference is that the fluorine-modified nanofiller is replaced with an equal amount of unmodified nanofiller. The rest of the composition and preparation method are the same as in Example 1, and will not be repeated here.

[0052] Comparative Example 3 This comparative example provides a high thermal conductivity and anti-aging PE pipe. Its raw material composition is similar to that in Example 1. The only difference is that the mass ratio of carbon nanotubes, graphene and nano alumina in the fluorine-modified nanofiller is 1:2-3:5. The other components and preparation methods are the same as in Example 1, and will not be repeated here.

[0053] Comparative Example 4 This comparative example provides a high thermal conductivity and anti-aging PE pipe. Its raw material composition is similar to that in Example 1. The only difference is that the composite anti-aging agent does not contain nano calcium carbonate. The rest of the composition and preparation method are the same as in Example 1. Only the nano calcium carbonate is not added during preparation, which will not be described again.

[0054] Comparative Example 5 This comparative example provides a high thermal conductivity and anti-aging PE pipe. Its raw material composition is similar to that in Example 1, except that far-infrared fibers are not added. The rest of the composition and preparation method are the same as in Example 1, except that far-infrared fibers are not added during preparation, which will not be described again.

[0055] Comparative Example 6 This comparative example provides a high thermal conductivity and anti-aging PE pipe. Its raw material composition is similar to that in Example 1. The only difference is that fluorine-modified nanofiller, composite anti-aging agent and far-infrared fiber are not added. The rest of the composition and preparation method are the same as in Example 1. However, fluorine-modified nanofiller, composite anti-aging agent and far-infrared fiber are not added during preparation, which will not be described again.

[0056] Test Example The thermal conductivity, aging resistance, and mechanical properties of the high thermal conductivity and anti-aging PE pipes obtained in Examples 1-4 and Comparative Examples 1-6 were tested respectively. Thermal conductivity was determined according to the standard "Test Method for Thermal Conductivity of Plastics - Heat-Protected Plate Method" (GB / T 3399-1982). Tensile strength and elongation at break were determined according to the standard "Determination of Tensile Properties of Thermoplastic Pipes - Part 3: Polyolefin Pipes" (GB / T8804.3-2003). Aging resistance was tested according to the standard "Differential Scanning Calorimetry of Plastics - Part 6: Determination of Oxidation Induction Time (Isothermal OIT) and Oxidation Induction Temperature (Dynamic OIT)" (GB / T 19466.6-2009). The test results are shown in Table 1.

[0057] Table 1

[0058] As shown in Table 1, compared with Example 1, the thermal conductivity of the PE pipes obtained when using organosilicon-modified nanofillers or unmodified nanofillers (Comparative Examples 1-2) is significantly lower than that of Example 1. In particular, the thermal conductivity of the unmodified Comparative Example 2 is reduced by more than half, indicating that the fluorine-modified nanofillers used in this invention can effectively improve the thermal conductivity of the PE pipes. Comparative Example 3 shows that when the amount of fluorine-modified nano-alumina used is significantly higher than that of carbon nanotubes and graphene, the relatively excessive fluorine-modified nano-alumina cannot completely form a point-line-surface structure, thus reducing the thermal conductivity. Comparative Example 4 shows that when the composite anti-aging agent does not contain nano-calcium carbonate, the oxidation induction time of the obtained PE pipes decreases significantly, indicating that the addition of nano-calcium carbonate can adsorb free radicals that are difficult for hyperbranched amine antioxidants to suppress, playing a key role in improving the antioxidant properties of PE pipes. Comparative Example 5, without the addition of far-infrared fibers, showed a significant decrease in the tensile strength and elongation at break of the resulting PE pipe, indicating that the addition of far-infrared fibers can effectively improve the mechanical properties of the PE pipe. Meanwhile, Comparative Example 6, without the addition of fluorine-modified nanofillers, composite anti-aging agents, and far-infrared fibers, exhibited a substantial reduction in thermal conductivity, antioxidant properties, and mechanical properties.

[0059] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high thermal conductive and ageing resistant PE pipe material, characterized in that, It is made from the following raw materials by weight: polyethylene 100 parts, fluorine modified nano filler 20-35 parts, composite anti-aging agent 8-15 parts, far infrared fiber 10-20 parts, lubricant 2-4 parts, dispersant 0.5-2 parts and plasticizer 0.4-1 part; The fluorine modified nano filler is composed of fluorine modified carbon nanotubes, fluorine modified graphene and fluorine modified nano aluminum oxide with a mass ratio of 1:2-3:1-2.

2. The high thermal conductive and aging resistant PE pipe according to claim 1, characterized in that, The preparation method of the fluorine modified nano filler is as follows: the carbon nanotubes, graphene and nano aluminum oxide are dispersed in water respectively to obtain a suspension, then the temperature is raised to 60-70℃, ammonium fluorozirconate is added respectively, the pH is adjusted to 2-4 with phosphoric acid, and then solid-liquid separation, washing and drying are carried out after stirring for 5-10h to obtain fluorine modified carbon nanotubes, fluorine modified graphene and fluorine modified nano aluminum oxide.

3. The high thermal conductive and aging resistant PE pipe according to claim 2, wherein, Each gram of the carbon nanotubes, graphene and nano aluminum oxide is dispersed in 50-100ml of water, and the mass ratio of the carbon nanotubes, graphene and nano aluminum oxide to ammonium fluorozirconate is 1:3-4, 1:2.5-3.5 and 1:2-3 respectively.

4. The high thermal conductive and aging resistant PE pipe according to claim 1, wherein, The composite anti-aging agent is composed of hyperbranched amine antioxidant, microbial inhibitor and nano calcium carbonate with a mass ratio of 2-3:1:

1.

5. The high thermal conductive and aging resistant PE pipe according to claim 4, characterized in that, The hyperbranched amine antioxidant is hyperbranched polyether amine or hyperbranched polyurethane amine; the microbial inhibitor is 2-methyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one or dodecyl dimethyl benzyl ammonium bromide.

6. Process for the preparation of the high thermally conductive and ageing resistant PE pipe according to any one of claims 1 to 5, characterized in that the step It comprises: The polyethylene, fluorine modified nano filler, composite anti-aging agent and far infrared fiber are pre-mixed in a high-speed mixer, then the lubricant, dispersant and plasticizer are added and mixed uniformly to obtain a pre-mixed material; The pre-mixed material is added into a double screw extruder for heating and extrusion granulation to obtain modified PE particles; The modified PE particles are added into a single screw, and then extrusion molding, cooling and shaping and traction winding are carried out to obtain high thermal conductivity anti-aging PE pipe material.

7. The method for preparing high thermal conductivity and anti-aging PE pipe as described in claim 6, characterized in that, The temperature of the pre-mixing is 90-100℃.

8. The method for preparing high thermal conductivity and anti-aging PE pipe as described in claim 6, characterized in that, The temperature of the heating and extrusion granulation is 150-220℃.

9. The application of the high thermal conductivity anti-aging PE pipe material of any one of claims 1-5 in a ground source heat pump system and a buried equipment.

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