High-thermal-conductivity graphene enhanced heat-shrinkable tube polymer material and preparation method thereof

Abstract

The invention belongs to the field of thermoplastic materials, and particularly relates to a high-thermal-conductivity graphene enhanced heat-shrinkable tube polymer material and a preparation method thereof. The high-thermal-conductivity graphene enhanced heat-shrinkable tube polymer material comprises the following components in parts by weight: 80-95 parts of heat-shrinkable tube matrix resin, 1-10 parts of functionalized graphene nanosheets and 4-15 parts of a hot melt adhesive material. Graphene is modified by a silane coupling agent, so that a three-dimensional heat-conducting network is constructed in heat-shrinkable tube matrix resin, and a multi-layer co-extrusion and radiation cross-linking process is combined, so that the heat conductivity coefficient is greater than or equal to 5W / (m.K), the heat-shrinkable time is shortened to be within 30s, and the flexibility (bending radius is less than or equal to 8mm) and the mechanical property are synergistically improved. The problem that a traditional heat shrink tube is poor in heat conduction is solved, and application occasions with high heat dissipation requirements are met.

Description

Technical Field

[0001] The present invention belongs to the field of thermoplastic materials, and in particular relates to a high thermal conductivity graphene-enhanced heat shrinkable tube polymer material and a preparation method thereof. Background Art

[0002] Heat shrink tubing is an insulating protective material that shrinks tightly around cables and connectors after being heated. Its core principle is to transform linear polymers into a network structure through radiation cross-linking, giving the material a "memory effect." Traditional heat shrink tubing is based on polyolefins (such as LDPE), and its thermal conductivity is as low as ≤0.3W / (m·K), resulting in the following problems:

[0003] (1) Low heat conduction efficiency: It takes a long time to heat (>60s) to shrink completely, resulting in high energy consumption and low installation efficiency;

[0004] (2) Uneven local heating: bubbles or cracks are likely to occur, affecting the sealing performance;

[0005] (3) Limitations of filler addition: Existing technologies attempt to add metal powders such as alumina to improve thermal conductivity, but the thermal conductivity coefficient is only increased to about 1.5W / (m·K). At the same time, it causes the density to increase by more than 40% and the flexibility to deteriorate (bending radius > 15mm), which cannot meet the requirements of high thermal conductivity and flexibility.

[0006] Therefore, there is an urgent need in the art for a heat shrink tubing material having both thermal conductivity and mechanical properties. Summary of the Invention

[0007] In view of the above-mentioned deficiencies in the prior art, the present invention provides a high thermal conductivity graphene enhanced heat shrinkable tube polymer material and a preparation method thereof.

[0008] In order to achieve the first object of the present invention, the present invention adopts the following technical solutions:

[0009] A high thermal conductivity graphene enhanced heat shrink tubing polymer material, comprising the following components in parts by weight:

[0010] Heat shrink tubing base resin: 80-95 parts;

[0011] Functionalized graphene nanosheets: 1-10 parts;

[0012] Hot melt adhesive material: 4 to 15 parts;

[0013] The total weight parts is 100 parts.

[0014] Optionally, the functionalized graphene nanosheets are obtained by oxidation of graphite sheets, and the surfaces of the functionalized graphene nanosheets are modified with hydroxyl functional groups.

[0015] Optionally, the specific surface area of ​​the functionalized graphene nanosheets is 500 to 800 m 2 / g.

[0016] Optionally, the heat shrink tube matrix resin is a mixture of low-density polyethylene and styrene-ethylene-butylene-styrene copolymer.

[0017] Optionally, the melt index of the low-density polyethylene in the heat shrink tube matrix resin is 0.5 to 3 g / 10 min when measured at 190° C. / 2.16 kg according to ASTM D1238.

[0018] Optionally, the styrene content of the styrene-ethylene-butylene-styrene copolymer in the heat shrinkable tube matrix resin is 28 to 35 wt %.

[0019] Optionally, the number average molecular weight of the styrene-ethylene-butylene-styrene copolymer in the heat shrinkable tube matrix resin is 70,000 to 150,000 g / mol.

[0020] Optionally, the mass ratio of low-density polyethylene to styrene-ethylene-butylene-styrene copolymer in the heat shrink tube matrix resin is 7:3.

[0021] Optionally, the hot melt adhesive material is ethylene-vinyl acetate copolymer, and the content of vinyl acetate is 25-35 wt%.

[0022] A second object of the present invention is to provide a method for preparing the above-mentioned high thermal conductivity graphene-enhanced heat shrinkable tube polymer material, which specifically comprises the following steps:

[0023] Treating the functionalized graphene nanosheets with a silane coupling agent to obtain modified functionalized graphene nanosheets;

[0024] The premix is ​​used as the outer layer and the hot melt adhesive material is used as the inner layer, and the heat shrink tube precursor is obtained by co-extrusion through a twin-screw extruder and then radiation cross-linking.

[0025] The heat shrink tube precursor is expanded to obtain a high thermal conductivity graphene enhanced heat shrink tube polymer material.

[0026] Optionally, the mixing temperature of the modified functionalized graphene nanosheets and the heat shrink tube matrix resin is 160-180° C., the mixing time is 10-20 min, and the speed of the internal mixer is 50-70 rpm.

[0027] Optionally, the temperature of the fourth zone of the twin-screw extruder is 150-180°C.

[0028] Optionally, the radiation cross-linking specifically includes:

[0029] The heat shrink tubing precursor was irradiated with an electron beam under a protective atmosphere with an irradiation dose of 150 kGy and a dose rate of 2 kGy / pass.

[0030] Beneficial effects of the present invention:

[0031] Breakthrough in thermal conductivity: Traditional heat shrink tubing reduces its thermal conductivity after adding hot melt adhesive. However, the present invention adds graphene to the tubing, which, by constructing a three-dimensional thermal conductive network, can still achieve improved thermal conductivity even with the addition of hot melt adhesive. Ultimately, the thermal conductivity is ≥5W / (m·K), and the shrinking time is shortened to within 30 seconds (64% shorter than traditional materials).

[0032] Synergistic improvement of mechanical properties: Silane coupling agent modification increases interfacial bonding strength by 200% and tensile strength by 26%;

[0033] Balance between flexibility and thermal conductivity: By regulating the graphene content and tube wall thickness, high thermal conductivity can be maintained when the bending radius is ≤8mm (compared to the aluminum oxide sample ≥15mm), which has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a flow chart of the preparation method of the high thermal conductivity graphene enhanced heat shrink tubing polymer material provided by the present invention. DETAILED DESCRIPTION

[0035] To make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0036] As used herein, the terms "comprises," "including," "having," "containing" or any other variations thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises a listed element is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0037] "Optional" or "either" means that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where the event occurs and instances where it does not.

[0038] The indefinite articles "a" and "an" before the elements or components of the present invention do not limit the quantity requirement (i.e. the number of times they appear). Therefore, "a" or "an" should be interpreted as including one or at least one, and the elements or components in the singular also include the plural form, unless the number is obviously limited to the singular form.

[0039] The terms "one embodiment," "some embodiments," "exemplarily," "specific examples," or "some examples" used in the present invention mean that a specific feature, structure, material, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment or example of the present invention. In this document, the exemplary expressions of the above terms do not necessarily refer to the same embodiment or example.

[0040] The numerical range of the present invention includes not only the point values ​​listed in the embodiments, but also any point values ​​not listed between the numerical ranges of the present invention. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0041] In the following examples, unless otherwise specified, all reagents and consumables were purchased from conventional reagent manufacturers in the field.

[0042] This embodiment provides a high thermal conductivity graphene-enhanced heat shrinkable tube polymer material, which includes the following components in parts by weight:

[0043] Heat shrink tubing base resin: 80-95 parts;

[0044] Functionalized graphene nanosheets: 1-10 parts;

[0045] Hot melt adhesive material: 4 to 15 parts;

[0046] The total weight parts is 100 parts.

[0047] In this embodiment, the functionalized graphene nanosheets are obtained by oxidation of graphite sheets, and the surface of the functionalized graphene nanosheets is modified with hydroxyl functional groups. Specifically, the preparation method of the functionalized graphene nanosheets is as follows:

[0048] (1) Pre-oxidation: Mix graphite with concentrated sulfuric acid, cool to 5°C, slowly add KMnO4 (control temperature <20°C), and stir for 2 hours;

[0049] (2) Deep oxidation: heat to 35°C and react for 12 hours;

[0050] (3) Termination of the reaction: Add 2 L of deionized water and add H2O2 dropwise until the solution turns golden yellow;

[0051] (4) Purification: centrifugation and washing with HCl and deionized water to pH = 6, and freeze-drying to obtain functionalized graphene nanosheets with surface modified with hydroxyl groups.

[0052] In this embodiment, graphene nanosheets with hydroxyl groups are more easily dispersed in the solvent / resin, thus avoiding agglomeration during subsequent mixing and solving the graphene dispersion problem.

[0053] In some specific embodiments, the specific surface area of ​​the functionalized graphene nanosheets is 500 to 800 m 2 / g, as an example, the specific surface area of ​​the functionalized graphene nanosheets can be 500m 2 / g、550m 2 / g、600m 2 / g、650m 2 / g、700m 2 / g、750m 2 / g、800m 2 / g, as long as the specific surface area of ​​the functionalized graphene nanosheets is within this range.

[0054] In some specific embodiments, the heat shrinkable tube base resin is a mixture of low-density polyethylene and styrene-ethylene-butylene-styrene copolymer.

[0055] In some specific embodiments, the melt index of the low-density polyethylene is 0.5 to 3 g / 10 min, as measured according to ASTM D1238 at 190°C / 2.16 kg. For example, the melt index of the low-density polyethylene under this measurement standard may be 0.5 g / 10 min, 1 g / 10 min, 1.5 g / 10 min, 2 g / 10 min, 2.5 g / 10 min, or 3 g / 10 min, as long as the melt index of the low-density polyethylene under this measurement standard is within this range.

[0056] In some specific embodiments, the styrene content of the styrene-ethylene-butylene-styrene copolymer is 28-35 wt %. As an example, the styrene content of the styrene-ethylene-butylene-styrene copolymer can be 28 wt %, 29 wt %, 30 wt %, 31 wt %, 32 wt %, 33 wt %, 34 wt %, or 35 wt %, as long as the styrene content of the styrene-ethylene-butylene-styrene copolymer is within this range.

[0057] In some specific embodiments, the number average molecular weight of the styrene-ethylene-butylene-styrene copolymer in the styrene-ethylene-butylene-styrene copolymer is 70,000 to 150,000 g / mol. As an example, the number average molecular weight of the styrene-ethylene-butylene-styrene copolymer in the styrene-ethylene-butylene-styrene copolymer can be 70,000 g / mol, 80,000 g / mol, 90,000 g / mol, 100,000 g / mol, 110,000 g / mol, 120,000 g / mol, 130,000 g / mol, 140,000 g / mol, or 150,000 g / mol, as long as the number average molecular weight of the styrene-ethylene-butylene-styrene copolymer in the styrene-ethylene-butylene-styrene copolymer is within this range.

[0058] In some specific embodiments, the mass ratio of low-density polyethylene to styrene-ethylene-butylene-styrene copolymer in the heat shrinkable tube matrix resin is 7:3.

[0059] In some specific embodiments, the hot melt adhesive material is ethylene-vinyl acetate copolymer, in which the content of vinyl acetate is 25-35wt%. As an example, the content of vinyl acetate in the hot melt adhesive material can be 25wt%, 28wt%, 30wt%, 32wt%, 34wt%, or 35wt%, as long as the content of vinyl acetate in the hot melt adhesive material is within this range.

[0060] A second embodiment of the present invention provides a method for preparing the above-mentioned high thermal conductivity graphene-enhanced heat shrinkable tube polymer material, which specifically includes the following steps:

[0061] S1. treating the functionalized graphene nanosheets with a silane coupling agent to obtain modified functionalized graphene nanosheets;

[0062] S2. The modified functionalized graphene nanosheets and the heat shrinkable tube matrix resin were mixed in an internal mixer to obtain a premix;

[0063] S3. The premix as the outer layer, the hot melt adhesive material as the inner layer, co-extruded by a twin-screw extruder and then irradiated and cross-linked to obtain a heat shrink tube precursor;

[0064] S4. Expand the heat shrink tube precursor to obtain a high thermal conductivity graphene enhanced heat shrink tube polymer material.

[0065] In some specific embodiments, step S1 of modifying the functionalized graphene nanosheets with a silane coupling agent specifically includes:

[0066] Functionalized graphene nanosheets were dispersed in ethanol, and 3% of the weight of the functionalized graphene was added as a silane coupling agent KH-550. The mixture was reacted at 60° C. for 2 hours and dried to obtain modified functionalized graphene nanosheets.

[0067] In some specific embodiments, the step of preparing the premix in step S2 specifically includes:

[0068] The modified functionalized graphene nanosheets and the heat shrink tube matrix resin are mixed in an internal mixer, the temperature is controlled at 160-180° C., the rotation speed is 50-70 rpm, and the mixing is carried out for 10-20 minutes to obtain a premix.

[0069] In this embodiment, the rotor peaks of the internal mixer and the wall of the internal mixer form a high shear zone (shear rate> 1000s -1 ), so that the graphene nanosheets are peeled and dispersed, and at the same time, the resin is softened at a temperature of 160-180°C, and the nanosheets are oriented through volume stretching rheology to build a continuous thermal conductive network.

[0070] In some specific embodiments, the rotation speed of the internal mixer in step S2 can be 50 rpm, 55 rpm, 60 rpm, 65 rpm, or 70 rpm, as long as the rotation speed of the internal mixer is within the range.

[0071] In some specific embodiments, the mixing time in step S2 can be 10 min, 12 min, 14 min, 15 min, 16 min, 18 min, or 20 min, as long as the mixing time is within the range.

[0072] In some specific embodiments, step S3 of preparing a heat shrinkable tube precursor specifically includes:

[0073] : Use the premix as the outer layer and the hot melt adhesive material as the inner layer, and set the temperature of the four zones of the extruder to 150℃ / 160℃ / 170℃ / 180℃.

[0074] In some specific embodiments, the specific parameters of the irradiation treatment of the heat shrink tube precursor in step S3 include:

[0075] Irradiation equipment: electron accelerator, energy 10MeV;

[0076] Key parameters:

[0077] Irradiation dose: 150 kGy;

[0078] Irradiation method: The heat shrink tube precursor passes through the scanning window at a constant speed, with a dose rate of 2 kGy / pass;

[0079] Environmental control: Protective atmosphere, control oxygen content <200ppm.

[0080] In this embodiment, a high-energy electron beam bombards the polymer molecular chain to generate free radicals; the free radicals recombine to form CC cross-linking bonds, transforming the linear structure into a three-dimensional network.

[0081] In some specific embodiments, step S4 of expanding the heat shrink tube precursor specifically includes:

[0082] A pneumatic tube expander is used to introduce compressed air into the material obtained after extrusion, and after heating and expansion, it is cooled and shaped to obtain a high thermal conductivity graphene enhanced heat shrink tube polymer material.

[0083] In a specific embodiment, the pipe expansion parameters of step S4 specifically include:

[0084] Using a pneumatic tube expander, 0.8MPa compressed air was introduced into the tube blank, infrared heating was maintained at 120°C, and after expansion, it was immersed in a 20°C water bath for 30 seconds to obtain a high thermal conductivity graphene-enhanced heat shrinkable tube polymer material with a diameter expansion of 1.8 times.

[0085] The present invention will be further described below by means of specific embodiments:

[0086] Description of relevant test standards used in the examples

[0087] Thermal conductivity: ASTM D5470 (steady-state heat flow method)

[0088] Heat shrinking time: UL 224 (Φ10mm copper rod, 150℃ hot air gun complete covering time)

[0089] Minimum bending radius: ASTM D790 (three-point bending method, minimum radius without pipe rupture)

[0090] Tensile strength: ASTM D638 (Type V spline, 50mm / min rate)

[0091] The English names of the raw materials used in the examples are briefly described

[0092] LDPE: Low-density polyethylene

[0093] SEBS: Styrene-ethylene-butylene-styrene copolymer

[0094] EVA: Ethylene-vinyl acetate copolymer

[0095] Example 1

[0096] The preparation method of the high thermal conductivity graphene enhanced heat shrinkable tube polymer material comprises the following steps:

[0097] (1) 100 g of hydroxylated graphene was dispersed in 3 L of ethanol, 3 g of KH-550 was added, and the mixture was stirred at 60 °C for 2 h. After filtration, the mixture was vacuum dried at 80 °C to obtain modified functionalized graphene nanosheets.

[0098] (2) The modified functionalized graphene nanosheets were mixed with 8.4 kg of LDPE and 3.6 kg of SEBS, and kneaded in an internal mixer at 170°C / 50 rpm for 15 min to obtain a premix.

[0099] (3) The premix was used as the outer layer and 1.0 kg of EVA was used as the inner layer, and a heat shrink tube precursor was obtained by extruding the premixed material through a twin-screw extruder.

[0100] (4) The heat shrink tube precursor is irradiated with 150 kGy of electron beam and expanded and shaped at 120° C. to obtain a high thermal conductivity graphene enhanced heat shrink tube polymer material.

[0101] Example 2

[0102] The preparation method of the high thermal conductivity graphene enhanced heat shrinkable tube polymer material comprises the following steps:

[0103] (1) 300 g of hydroxylated graphene was dispersed in 3 L of ethanol, 9 g of KH-550 was added, and the mixture was stirred at 60 °C for 2 h. After filtration, the mixture was vacuum-dried at 80 °C to obtain modified functionalized graphene nanosheets.

[0104] (2) The modified functionalized graphene nanosheets were mixed with 8.2 kg of LDPE and 3.5 kg of SEBS, and kneaded in an internal mixer at 170°C / 50 rpm for 15 min to obtain a premix.

[0105] (3) The premix was used as the outer layer and 1.0 kg of EVA was used as the inner layer, and a heat shrink tube precursor was obtained by extruding the premixed material through a twin-screw extruder.

[0106] (4) The heat shrink tube precursor is irradiated with 150 kGy of electron beam and expanded and shaped at 120° C. to obtain a high thermal conductivity graphene enhanced heat shrink tube polymer material.

[0107] Example 3

[0108] The preparation method of the high thermal conductivity graphene enhanced heat shrinkable tube polymer material comprises the following steps:

[0109] (1) 500 g of hydroxylated graphene was dispersed in 3 L of ethanol, 15 g of KH-550 was added, and the mixture was stirred at 60 °C for 2 h. After filtration, the mixture was vacuum dried at 80 °C to obtain modified functionalized graphene nanosheets.

[0110] (2) The modified functionalized graphene nanosheets were mixed with 8.0 kg of LDPE and 3.4 kg of SEBS, and kneaded in an internal mixer at 170°C / 50 rpm for 15 min to obtain a premix.

[0111] (3) The premix was used as the outer layer and 1.0 kg of EVA was used as the inner layer, and a heat shrink tube precursor was obtained by extruding the premixed material through a twin-screw extruder.

[0112] (4) The heat shrink tube precursor is irradiated with 150 kGy of electron beam and expanded and shaped at 120° C. to obtain a high thermal conductivity graphene enhanced heat shrink tube polymer material.

[0113] Comparative Example 1

[0114] The only difference between this comparative example and Example 3 is that no functionalized graphene nanosheets are added. The specific preparation method includes the following steps:

[0115] (1) The modified functionalized graphene nanosheets were mixed with 7 kg of LDPE and 3 kg of SEBS, and kneaded in an internal mixer at 170°C / 50 rpm for 15 min to obtain a premix.

[0116] (2) The premix was used as the outer layer and 1.0 kg of EVA was used as the inner layer, and a heat shrink tube precursor was obtained by extruding the premixed material through a twin-screw extruder.

[0117] (3) The heat shrink tube precursor is irradiated with 150 kGy of electron beam and expanded and shaped at 120° C. to obtain a high thermal conductivity graphene enhanced heat shrink tube polymer material.

[0118] Comparative Example 2

[0119] The difference between this comparative example and Example 3 is that the graphene nanosheets are replaced with aluminum oxide in equal parts by weight, as follows:

[0120] (1) 500 g of alumina was mixed with 8.0 kg of LDPE and 3.4 kg of SEBS, and the mixture was kneaded in an internal mixer at 170° C. / 50 rpm for 15 min to obtain a premix.

[0121] (2) The premix was used as the outer layer and 1.0 kg of EVA was used as the inner layer, and a heat shrink tube precursor was obtained by extruding the premixed material through a twin-screw extruder.

[0122] (3) The heat shrink tube precursor is irradiated with 150 kGy of electron beam and expanded and shaped at 120° C. to obtain a high thermal conductivity graphene enhanced heat shrink tube polymer material.

[0123] Performance Testing

[0124] The performance tests of the heat shrink tubing obtained in Examples 1 to 3 and Comparative Examples 1 to 2 were performed as follows:

[0125]

[0126]

[0127] The performance test results show that:

[0128] 1. Thermal conductivity: The decisive role of graphene three-dimensional network

[0129] Gradient law: Graphene content ↑ → thermal conductivity ↑ (1 part → 5 parts: 2.5 → 7.8 W / (m·K))

[0130] Horizontal comparison:

[0131] Comparative Example 2 (5 parts of aluminum oxide): only 1.5 W / (m·K) (less than 20% of Example 3)

[0132] Mechanism difference: Aluminum oxide forms a point-like heat conduction path, and graphene builds a continuous three-dimensional network.

[0133] 2. Heat shrinkage efficiency: qualitative improvement driven by thermal conductivity

[0134] Group Heat shrink time Shortened relative to Comparative Example 1 Comparative Example 2 50s 28.6％ Example 3 25s 64.3％

[0135] Thermodynamic explanation: The increase in thermal conductivity leads to a higher heat transfer rate within the tube wall, thereby triggering the overall shape memory effect faster.

[0136] 3. Flexibility: The essential difference between graphene and aluminum oxide

[0137] Bending radius comparison:

[0138]

[0139]

[0140] root cause:

[0141] (1) Aluminum oxide is a rigid sphere (particle size is usually 1 μm, stress concentration causes brittle cracking;

[0142] (2) Graphene is a two-dimensional flexible sheet (sheet diameter 5 to 20 μm) that can bend with the deformation of the resin and has stronger plasticity.

[0143] It should be understood that the application of the present invention is not limited to the above examples. For those skilled in the art, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A high thermal conductivity graphene enhanced heat shrinkable tube polymer material, characterized in that: In parts by weight, it comprises the following components: Heat shrink tubing base resin: 80-95 parts; Functionalized graphene nanosheets: 1-10 parts; Hot melt adhesive material: 4 to 15 parts; The total weight of the parts is 100 parts; The functionalized graphene nanosheets are obtained by oxidation of graphite sheets, and the surfaces of the functionalized graphene nanosheets are modified with hydroxyl functional groups; The specific surface area of ​​the functionalized graphene nanosheet is 500 to 800 m 2 / g.

2. The high thermal conductivity graphene enhanced heat shrinkable tube polymer material according to claim 1, characterized in that: The heat shrink tube matrix resin is a mixture of low-density polyethylene and styrene-ethylene-butylene-styrene copolymer.

3. The high thermal conductivity graphene enhanced heat shrinkable tube polymer material according to claim 2, characterized in that: The melt index of the low-density polyethylene in the heat shrink tube matrix resin is 0.5-3 g / 10 min when measured under the conditions of 190° C. / 2.16 kg according to ASTM D1238.

4. The high thermal conductivity graphene enhanced heat shrinkable tube polymer material according to claim 2, characterized in that: The styrene content of the styrene-ethylene-butylene-styrene copolymer in the heat shrink tube matrix resin is 28-35 wt %, and the number average molecular weight of the styrene-ethylene-butylene-styrene copolymer is 70,000-150,000 g / mol.

5. The high thermal conductivity graphene enhanced heat shrinkable tube polymer material according to claim 2, characterized in that: The mass ratio of the low-density polyethylene in the heat shrink tube matrix resin to the styrene-ethylene-butylene-styrene copolymer is 7:

3.

6. The high thermal conductivity graphene enhanced heat shrinkable tube polymer material according to claim 1, characterized in that: The hot melt adhesive material is ethylene-vinyl acetate copolymer, and the content of vinyl acetate is 25-35 wt%.

7. A method for preparing the high thermal conductivity graphene enhanced heat shrinkable tube polymer material according to any one of claims 1 to 6, characterized in that: The following steps are involved: Treating the functionalized graphene nanosheets with a silane coupling agent to obtain modified functionalized graphene nanosheets; Mixing the modified functionalized graphene nanosheets and the heat shrink tube matrix resin in an internal mixer to obtain a premix; The premix is ​​used as the outer layer and the hot melt adhesive material is used as the inner layer, and the premix is ​​co-extruded through a twin-screw extruder and then irradiated and cross-linked to obtain a heat shrink tube precursor; The heat shrink tube precursor is expanded to obtain a high thermal conductivity graphene enhanced heat shrink tube polymer material.

8. The method for preparing the high thermal conductivity graphene enhanced heat shrinkable tube polymer material according to claim 7, characterized in that: The mixing temperature of the modified functionalized graphene nanosheets and the heat shrink tube matrix resin is 160-180° C., the mixing time is 10-20 minutes, and the rotation speed of the internal mixer is 50-70 rpm.

9. The method for preparing the high thermal conductivity graphene enhanced heat shrinkable tube polymer material according to claim 7, characterized in that: The temperature of the four zones of the twin-screw extruder is 150-180°C.

10. The method for preparing a high thermal conductivity graphene enhanced heat shrinkable tube polymer material according to claim 7, characterized in that: The radiation cross-linking specifically includes: The heat shrink tube precursor is subjected to electron beam irradiation under a protective atmosphere, with an irradiation dose of 150 kGy and a dose rate of 2 kGy / pass.

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