Heat shrink tube and preparation process thereof

Abstract

The invention relates to the field of thermal shrinkage materials, and particularly discloses a thermal shrinkage tube and a preparation process thereof.The tube is prepared from, by weight, 25-35 parts of EVA, 5-15 parts of POE, 5-15 parts of metallocene polyethylene, 5-15 parts of aluminum hydroxide, hyperbranched polyethyleneimine grafted silicon carbide nanowires and surface fluorinated silicon carbide nanowires according to a certain mass ratio. The thermal shrinkage material prepared by the invention has both tensile strength and thermal shrinkage performance.

Description

Technical Field

[0001] The present invention relates to the field of heat shrinkable materials, and more specifically, to a heat shrinkable tube and a preparation process thereof. Background Art

[0002] Heat shrink tubing is a kind of tubing with high-temperature shrinkage, soft flame retardancy, insulation and corrosion resistance. It is widely used in insulation protection of various wiring harnesses, solder joints, inductors, and rust and corrosion prevention of metal tubes and rods. The material used for heat shrink tubing is in a glassy state at room temperature and becomes a highly elastic state after heating; during production, the heat shrink tubing is heated to a highly elastic state, a load is applied to expand it, and it is quickly cooled while maintaining the expansion to enter a glassy state. Common heat shrink tubing includes PVC heat shrink tubing, PET heat shrink tubing, and heat shrink tubing containing glue, etc., but these types of heat shrink tubing are not flexible enough to meet the higher requirements for heat shrink wrapping. EVA material has the advantages of low-temperature shrinkage, soft flame retardancy, insulation and environmental protection, but its tensile strength is not high. If reinforcing fillers are added to it, its shrinkage performance will be affected and it cannot be tightly coated. Therefore, the applicant considers how to provide a heat shrink tubing with both high tensile strength and heat shrinkage performance, which is of great significance for expanding the application of EVA heat shrink tubing. Summary of the invention

[0003] In order to solve the problem that EVA heat shrinkable materials have both tensile strength and heat shrinkage performance, the present application provides a heat shrinkable tube and a preparation process thereof.

[0004] In a first aspect, the present application provides a heat shrinkable tube, characterized in that it comprises the following components in parts by weight: 25-35 parts of EVA, 5-15 parts of POE, 5-15 parts of metallocene polyethylene, 5-15 parts of aluminum hydroxide, and 5-15 parts of silicon carbide nanowires.

[0005] By adopting the above scheme, ethylene-vinyl acetate copolymer has good cleanliness and mechanical strength, and the molecular chain is amorphous, with good molecular chain segment movement ability. The heat shrink tube prepared by using ethylene-vinyl acetate copolymer can have good shrinkage ability. POE does not have a polyethylene chain crystal region and a certain amount of octene. The polyethylene chain crystal region acts as a physical crosslinking point. A certain amount of octene weakens the crystal region and increases the amorphous performance of the material, resulting in the shrinkage performance of the heat shrink tube. Metallocene has a large molecular weight, and further adding a certain amount of metallocene polyethylene can improve the elongation at break of the material. Adding aluminum hydroxide improves flame retardancy. Silicon carbide nanowires have high strength and enhance the heat shrink tube. The heat shrink tube prepared by the above mass parts has high tensile strength, a large proportion of amorphous state, and good heat shrinkage performance.

[0006] In a specific embodiment, the silicon carbide nanowires include hyperbranched polyethyleneimine grafted silicon carbide nanowires and surface fluorinated silicon carbide nanowires.

[0007] Silicon carbide nanowires have high strength and reinforce the prepared heat shrinkable tube. Hyperbranched polyethyleneimine has certain adsorption and steric hindrance. Surface fluorinated silicon carbide has low surface energy, good dispersibility and is relatively smooth. By adding hyperbranched polyethyleneimine grafted silicon carbide nanowires and surface fluorinated silicon carbide nanowires together, the smooth surface fluorinated silicon carbide nanowires and the hyperbranched polyethyleneimine grafted silicon carbide nanowires are loosely interlaced. After the heat shrinkage of the heat shrinkable tube, it may be because the two have a certain degree of molecular chain segment movement ability in the system. The smooth surface fluorinated silicon carbide nanowires move in the hyperbranched polyethyleneimine grafted silicon carbide nanowire network with a certain steric hindrance. As the heat shrinkage proceeds, the interlacing effect becomes tighter. The steric hindrance shielding and mechanical locking of the hyperbranched polyethyleneimine make it more difficult to pull out the tightly interlaced nanowires. Therefore, the prepared heat shrinkable tube has both high tensile strength and good shrinkage effect. At the same time, the rich vinyl groups on the hyperbranched polyethyleneimine grafted silicon carbide nanowires may undergo addition reaction with a large amount of vinyl groups in the system, and the connection strength between the hyperbranched polyethyleneimine grafted silicon carbide nanowires and the matrix is ​​higher. The surface fluorinated silicon carbide nanowires after interlacing and shrinkage have better connection strength with the hyperbranched polyethyleneimine grafted silicon carbide nanowires. The combined effect makes the prepared heat shrinkable tube have higher strength.

[0008] In a specific embodiment, the preparation steps of hyperbranched polyethyleneimine grafted silicon carbide nanowires include: epoxy-modifying silicon carbide nanowires to obtain modified silicon carbide nanowires, then adding the modified silicon carbide nanowires and hyperbranched polyethyleneimine into deionized water and stirring evenly, adjusting the pH value, heating the reaction, centrifuging, washing, and drying to obtain hyperbranched polyethyleneimine grafted silicon carbide nanowires.

[0009] Preferably, the preparation steps of hyperbranched polyethyleneimine grafted silicon carbide nanowires include:

[0010] Add 5g of silicon carbide nanowires and 3g of epoxysilane coupling agent KH560 to 100g of 60vt% ethanol aqueous solution, stir evenly, adjust the pH to 6, heat to 75°C and stir for 2 hours, centrifuge, wash with ethanol and deionized water three times in sequence, and dry to obtain modified silicon carbide nanowires. Then add the prepared modified silicon carbide nanowires and 3g of hyperbranched polyethyleneimine to deionized water and stir evenly, adjust the pH to 5, heat at 46°C for 6h, centrifuge, wash, and dry to obtain hyperbranched polyethyleneimine grafted silicon carbide nanowires.

[0011] By adopting the above scheme, the preparation method is simple, the hyperbranched polyethyleneimine on the surface of the silicon carbide nanowires is relatively uniform and the quantity is appropriate. There will be no excessive steric hindrance due to the excessive number of hyperbranched groups, which will cause the silicon carbide nanowires to be unable to slide during the heat shrinkage process and reduce the shrinkage effect. There will also be no too loose interlacing of the silicon carbide nanowires due to the small steric hindrance, which will cause limited reinforcement effect on the heat shrinkable tube.

[0012] In a specific embodiment, the preparation steps of surface fluorinated silicon carbide nanowires include: adding silicon carbide nanowires and fluorinated silane coupling agent to ethanol aqueous solution, stirring evenly, adjusting pH, heating reaction, centrifuging, washing, and drying to obtain surface fluorinated silicon carbide nanowires.

[0013] By adopting the above scheme, the preparation method is simple, the fluorination effect is good, the surface of the prepared surface fluorinated silicon carbide nanowires is smooth, and a good slip effect can be generated in the middle of the hyperbranched polyethyleneimine grafted silicon carbide nanowires.

[0014] In a specific embodiment, the silicon carbide nanowires have a diameter of 1-5 μm and a length of 50-100 μm.

[0015] The applicant has found that the carbon nanowires under this specification have higher strength and aspect ratio, and can form better loose interlacing with a smaller addition amount, while not being tightly entangled to reduce the heat shrinkage effect.

[0016] In a specific embodiment, the molecular weight of the hyperbranched polyethyleneimine is 10,000-11,000.

[0017] By adopting the above scheme, the viscosity and steric hindrance of the hyperbranched polyethyleneimine at this time are suitable for the system setting of the present application, which can achieve good interpenetration enhancement without excessive steric hindrance affecting the slippage between fibers.

[0018] In a specific embodiment, the mass ratio of EVA to silicon carbide nanowires is 3-3.5:1.

[0019] By adopting the above scheme, silicon carbide nanowires are evenly distributed and interspersed in the system to form a network, which will not reduce the heat shrinkage effect too much and will not reduce the reinforcement effect too little.

[0020] In a specific embodiment, the mass ratio of the hyperbranched polyethyleneimine grafted silicon carbide nanowires to the surface fluorinated silicon carbide nanowires is 1-1.5:1.

[0021] By adopting the above scheme, the hyperbranched polyethyleneimine grafted silicon carbide nanowires and the surface fluorinated silicon carbide nanowires are uniformly and loosely interspersed, and the amount of hyperbranched polyethyleneimine is appropriate, which can effectively prevent the nanowires from being pulled out while not being too dense to cause a poor interlacing effect. The surface fluorinated silicon carbide nanowires with a smooth surface can achieve better slippage.

[0022] In a second aspect, the present application provides a process for preparing a heat shrinkable tube, which is characterized in that it includes the following steps: weighing each component, mixing them evenly by mass, extruding them, and then irradiating and expanding them to obtain a heat shrinkable tube.

[0023] By adopting the above scheme, the preparation process is relatively simple, which is suitable for the component setting of the present application, and the prepared heat shrinkable tube has good heat shrinkage effect and high tensile strength.

[0024] In a specific embodiment, the irradiation dose is 70-200 kGy.

[0025] By adopting the above scheme, the thermoplastic tube obtained after irradiation is more compact and smooth, the degree of cross-linking of each component in the system is appropriate, and it has both a certain tensile strength and a good shrinkage effect.

[0026] In summary, this application has the following beneficial effects:

[0027] In the present application, EVA, POE and metallocene polyethylene are used together to produce a heat shrinkable tube having a large amorphous area, and the heat shrinkable tube is reinforced by silicon carbide nanowires, so that the heat shrinkable tube has both good shrinkage effect and high tensile strength.

[0028] By further limiting the silicon carbide nanowires to include hyperbranched polyethyleneimine grafted silicon carbide nanowires and surface fluorinated silicon carbide nanowires, and limiting the preparation steps and size of the silicon carbide nanowires and the molecular weight of the hyperbranched polyethyleneimine, the interlacing slip and steric locking effects between the nanowires are better. By further limiting the mass ratio of each component, the performance of the heat shrinkable tube is further improved. DETAILED DESCRIPTION

[0029] In order to further help understand the technical solution of the present invention, several specific embodiments are provided to describe the technical solution of the present invention in more detail. All the embodiments described are only partial embodiments of the present invention, not all; the embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The following embodiments are further explanations of the present invention, and the present invention is not limited thereto.

[0030] The components of the preparation examples used in the examples of the present application are all components obtained by the preparation examples. Unless otherwise specified, the experimental reagents are all conventional commercial brands or obtained by conventional preparation processes.

[0031] Silicon carbide nanowires with a diameter of 1-5 μm and a length of 50-100 μm and with a diameter of 0.1-0.5 μm and a length of 100-150 μm were purchased from Shanghai Naio Nano Technology Co., Ltd. Silicon carbide powder was purchased from Zhengzhou Xinli Wear Resistant Materials Co., Ltd. Hyperbranched polyethyleneimine with a number average molecular weight of 10 Kg / mol and 25 Kg / mol were purchased from Aldrich.

[0032] Preparation Example

[0033] Hyperbranched polyethyleneimine grafted silicon carbide nanowires:

[0034] Preparation Example 1:

[0035] Add 5g of silicon carbide nanowires and 3g of epoxysilane coupling agent KH560 to 100g of 60vt% ethanol aqueous solution, stir evenly, adjust the pH to 6, heat to 75°C and stir for 2 hours, centrifuge, wash with ethanol and deionized water three times in sequence, and dry to obtain modified silicon carbide nanowires. Then add the prepared modified silicon carbide nanowires and 3g of hyperbranched polyethyleneimine to deionized water and stir evenly, adjust the pH to 5, heat at 46°C for 6h, centrifuge, wash, and dry to obtain hyperbranched polyethyleneimine grafted silicon carbide nanowires.

[0036] The diameter of the silicon carbide nanowires in this preparation example is 1-5 μm and the length is 50-100 μm; the number average molecular weight of the hyperbranched polyethyleneimine is 10 Kg / mol.

[0037] Preparation Example 2:

[0038] Add 5g of silicon carbide nanowires and 3g of epoxysilane coupling agent KH560 to 100g of 60vt% ethanol aqueous solution, stir evenly, adjust the pH to 6, heat to 75°C and stir for 2 hours, centrifuge, wash with ethanol and deionized water three times in sequence, and dry to obtain modified silicon carbide nanowires. Then add the prepared modified silicon carbide nanowires and 3g of hyperbranched polyethyleneimine to deionized water and stir evenly, adjust the pH to 5, heat at 46°C for 6h, centrifuge, wash, and dry to obtain hyperbranched polyethyleneimine grafted silicon carbide nanowires.

[0039] The diameter of the silicon carbide nanowires in this preparation example is 0.1-0.5 μm, and the length is 100-150 μm; the number average molecular weight of the hyperbranched polyethyleneimine is 10 Kg / mol.

[0040] Preparation Example 3:

[0041] Add 5g of silicon carbide nanowires and 3g of epoxysilane coupling agent KH560 to 100g of 60vt% ethanol aqueous solution, stir evenly, adjust the pH to 6, heat to 75°C and stir for 2 hours, centrifuge, wash with ethanol and deionized water three times in sequence, and dry to obtain modified silicon carbide nanowires. Then add the prepared modified silicon carbide nanowires and 3g of hyperbranched polyethyleneimine to deionized water and stir evenly, adjust the pH to 5, heat at 46°C for 6h, centrifuge, wash, and dry to obtain hyperbranched polyethyleneimine grafted silicon carbide nanowires.

[0042] The diameter of the silicon carbide nanowires in this preparation example is 1-5 μm and the length is 50-100 μm; the number average molecular weight of the hyperbranched polyethyleneimine is 25 Kg / mol.

[0043] Surface fluorinated silicon carbide nanowires

[0044] Preparation Example 4:

[0045] 5 g of silicon carbide nanowires and 4 g of heptadecafluorodecyltrimethoxysilane were added to 200 ml of 60 vt% ethanol aqueous solution, stirred evenly, adjusted the pH to 4, heated at 40° C. for 2 hours, centrifuged, washed, and dried to obtain surface fluorinated silicon carbide nanowires.

[0046] The silicon carbide nanowires in this preparation example have a diameter of 1-5 μm and a length of 50-100 μm.

[0047] Surface amino-treated silicon carbide nanowires

[0048] Preparation Example 5:

[0049] 5 g of silicon carbide nanowires and 4 g of aminosilane coupling agent KH550 were added to 200 ml of 60 vt% ethanol aqueous solution, stirred evenly, adjusted the pH to 4, heated at 40° C. for reaction for 2 hours, centrifuged, washed, and dried to obtain surface amino-modified silicon carbide nanowires.

[0050] Example

[0051] Example 1

[0052] This embodiment includes the following raw materials: 250 g EVA, 50 g POE, 150 g metallocene polyethylene, 50 g aluminum hydroxide, and 50 g silicon carbide nanowires. The silicon carbide nanowires have a diameter of 1-5 μm and a length of 50-100 μm.

[0053] The preparation steps include: weighing each component, mixing them evenly by mass, extruding them at 350°C using a twin-screw extruder, with an extrusion speed of 1m / min and a screw speed of 400r / min, and then irradiating them with 100kGy and expanding them in a hot chamber at 220°C to obtain a heat shrink tube.

[0054] Example 2

[0055] This embodiment includes the following raw materials: 350 g EVA, 150 g POE, 50 g metallocene polyethylene, 50 g aluminum hydroxide, and 150 g silicon carbide nanowires. The silicon carbide nanowires have a diameter of 1-5 μm and a length of 50-100 μm.

[0056] The preparation steps include: weighing each component, mixing them evenly by mass, extruding them at 350°C using a twin-screw extruder, with an extrusion speed of 1m / min and a screw speed of 400r / min, and then irradiating them with 100kGy and expanding them in a hot chamber at 220°C to obtain a heat shrink tube.

[0057] Example 3

[0058] This embodiment includes the following raw materials: 300 g of EVA, 100 g of POE, 100 g of metallocene polyethylene, 50 g of aluminum hydroxide, and 100 g of silicon carbide nanowires. The silicon carbide nanowires have a diameter of 1-5 μm and a length of 50-100 μm.

[0059] The preparation steps include: weighing each component, mixing them evenly by mass, extruding them at 350°C using a twin-screw extruder, with an extrusion speed of 1m / min and a screw speed of 400r / min, and then irradiating them with 100kGy and expanding them in a hot chamber at 220°C to obtain a heat shrink tube.

[0060] Example 4

[0061] This embodiment includes the following raw materials: 300 g of EVA, 100 g of POE, 100 g of metallocene polyethylene, 50 g of aluminum hydroxide, 50 g of hyperbranched polyethyleneimine grafted silicon carbide nanowires prepared in Preparation Example 1, and 50 g of surface fluorinated silicon carbide nanowires prepared in Preparation Example 4.

[0062] The preparation steps include: weighing each component, mixing them evenly by mass, extruding them at 350°C using a twin-screw extruder, with an extrusion speed of 1m / min and a screw speed of 400r / min, and then irradiating them with 100kGy and expanding them in a hot chamber at 220°C to obtain a heat shrink tube.

[0063] Example 5

[0064] This embodiment includes the following raw materials: 300 g of EVA, 100 g of POE, 100 g of metallocene polyethylene, 50 g of aluminum hydroxide, 60 g of hyperbranched polyethyleneimine grafted silicon carbide nanowires prepared in Preparation Example 1, and 60 g of surface fluorinated silicon carbide nanowires prepared in Preparation Example 4.

[0065] The preparation steps include: weighing each component, mixing them evenly by mass, extruding them at 350°C using a twin-screw extruder, with an extrusion speed of 1m / min and a screw speed of 400r / min, and then irradiating them with 100kGy and expanding them in a hot chamber at 220°C to obtain a heat shrink tube.

[0066] Example 6

[0067] This embodiment includes the following raw materials: 300 g of EVA, 100 g of POE, 100 g of metallocene polyethylene, 50 g of aluminum hydroxide, 70 g of hyperbranched polyethyleneimine grafted silicon carbide nanowires prepared in Preparation Example 1, and 30 g of surface fluorinated silicon carbide nanowires prepared in Preparation Example 4.

[0068] The preparation steps include: weighing each component, mixing them evenly by mass, extruding them at 350°C using a twin-screw extruder, with an extrusion speed of 1m / min and a screw speed of 400r / min, and then irradiating them with 100kGy and expanding them in a hot chamber at 220°C to obtain a heat shrink tube.

[0069] Example 7

[0070] This embodiment includes the following raw materials: 300 g of EVA, 100 g of POE, 100 g of metallocene polyethylene, 50 g of aluminum hydroxide, 50 g of hyperbranched polyethyleneimine grafted silicon carbide nanowires prepared in Preparation Example 2, and 50 g of surface fluorinated silicon carbide nanowires prepared in Preparation Example 4.

[0071] The preparation steps include: weighing each component, mixing them evenly by mass, extruding them at 350°C using a twin-screw extruder, with an extrusion speed of 1m / min and a screw speed of 400r / min, and then irradiating them with 100kGy and expanding them in a hot chamber at 220°C to obtain a heat shrink tube.

[0072] Example 8

[0073] This embodiment includes the following raw materials: 300 g of EVA, 100 g of POE, 100 g of metallocene polyethylene, 50 g of aluminum hydroxide, 50 g of hyperbranched polyethyleneimine grafted silicon carbide nanowires prepared in Preparation Example 3, and 50 g of surface fluorinated silicon carbide nanowires prepared in Preparation Example 4.

[0074] The preparation steps include: weighing each component, mixing them evenly by mass, extruding them at 350°C using a twin-screw extruder, with an extrusion speed of 1m / min and a screw speed of 400r / min, and then irradiating them with 100kGy and expanding them in a hot chamber at 220°C to obtain a heat shrink tube.

[0075] Example 9

[0076] This embodiment includes the following raw materials: 300 g of EVA, 100 g of POE, 100 g of metallocene polyethylene, 50 g of aluminum hydroxide, 50 g of hyperbranched polyethyleneimine grafted silicon carbide nanowires prepared in Preparation Example 1, and 50 g of surface amino-modified silicon carbide nanowires prepared in Preparation Example 5.

[0077] The preparation steps include: weighing each component, mixing them evenly by mass, extruding them at 350°C using a twin-screw extruder, with an extrusion speed of 1m / min and a screw speed of 400r / min, and then irradiating them with 100kGy and expanding them in a hot chamber at 220°C to obtain a heat shrink tube.

[0078] Example 10

[0079] This embodiment includes the following raw materials: 300 g of EVA, 100 g of POE, 100 g of metallocene polyethylene, 50 g of aluminum hydroxide, and 100 g of hyperbranched polyethyleneimine grafted silicon carbide nanowires prepared in Preparation Example 1.

[0080] The preparation steps include: weighing each component, mixing them evenly by mass, extruding them at 350°C using a twin-screw extruder, with an extrusion speed of 1m / min and a screw speed of 400r / min, and then irradiating them with 100kGy and expanding them in a hot chamber at 220°C to obtain a heat shrink tube.

[0081] Embodiment 11

[0082] This embodiment includes the following raw materials: 300 g of EVA, 100 g of POE, 100 g of metallocene polyethylene, 50 g of aluminum hydroxide, and 100 g of surface fluorinated silicon carbide nanowires prepared in Preparation Example 4.

[0083] The preparation steps include: weighing each component, mixing them evenly by mass, extruding them at 350°C using a twin-screw extruder, with an extrusion speed of 1m / min and a screw speed of 400r / min, and then irradiating them with 100kGy and expanding them in a hot chamber at 220°C to obtain a heat shrink tube.

[0084] Comparative Example

[0085] Comparative Example 1

[0086] This comparative example includes the following raw materials: 450 g of EVA, 50 g of POE, 30 g of metallocene polyethylene, 50 g of aluminum hydroxide, and 100 g of silicon carbide powder.

[0087] The preparation steps include: weighing each component, mixing them evenly by mass, extruding them at 350°C using a twin-screw extruder, with an extrusion speed of 1m / min and a screw speed of 400r / min, and then irradiating them with 100kGy and expanding them in a hot chamber at 220°C to obtain a heat shrink tube.

[0088] Performance testing

[0089] Test 1: The tensile strength of the samples prepared in each embodiment and comparative example was tested with reference to the standard "GB / T 1040". The test results are shown in Table 1.

[0090] Test 2: The inner diameter R1 of the samples prepared in each embodiment and comparative example was tested, and then heated at 110°C to a completely retracted state R2. The shrinkage rate was calculated according to (R1-R2) / R1×100%. The results are shown in Table 1.

[0091] Table 1 Tensile strength (MPa) Shrinkage rate (%) Example 1 14.0 59.2 Example 2 14.5 56.9 Example 3 14.3 58.2 Example 4 15.9 66.8 Example 5 16.5 58.1 Example 6 16.2 61.8 Example 7 13.7 55.8 Example 8 15.1 53.2 Example 9 15.7 51.2 Example 10 16.3 61.1 Embodiment 11 15.5 69.3 Comparative Example 1 8.4 62.3

[0092] In combination with Examples 1-3, Comparative Example 1 and Table 1, the heat shrinkable tube prepared by using the components of the present application in a certain mass ratio and preparation process has both high tensile strength and large shrinkage rate.

[0093] In combination with Example 3, Examples 4-6, 10-11 and Table 1, the present application limits the silicon carbide nanowires to include a certain mass proportion of hyperbranched polyethyleneimine grafted silicon carbide nanowires and surface fluorinated silicon carbide nanowires, and further limits the mass ratio with EVA, so that a better interlaced locking knot reinforcement is formed in the prepared heat shrinkable tube system, and at the same time, the nanowires can slide better to optimize the shrinkage process.

[0094] In combination with Example 3, Examples 7-9 and Table 1, the present application limits the size of silicon carbide nanowires so that the nanowires have higher strength and interlacing effect without excessive entanglement affecting shrinkage, and further optimizes the steric locking effect by limiting the molecular weight of hyperbranched polyethyleneimine.

[0095] The specific embodiment adopted in this application is only an explanation of this application, and it is not a limitation of this application. After reading this specification, technical personnel in this field can make non-creative modifications to this embodiment as needed, but as long as it is within the scope of the claims of this application, it is protected by the patent law.

Claims

1. A heat shrink tube, characterized in that: The invention comprises the following raw materials in parts by weight: 25-35 parts of EVA, 5-15 parts of POE, 5-15 parts of metallocene polyethylene, 5-15 parts of aluminum hydroxide and 5-15 parts of silicon carbide nanowires.

2. The heat shrinkable tube according to claim 1, characterized in that: The silicon carbide nanowires include hyperbranched polyethyleneimine grafted silicon carbide nanowires and surface fluorinated silicon carbide nanowires.

3. The heat shrinkable tube according to claim 2, characterized in that: The preparation steps of the hyperbranched polyethyleneimine grafted silicon carbide nanowires include: epoxy-modifying the silicon carbide nanowires to obtain modified silicon carbide nanowires, then adding the modified silicon carbide nanowires and hyperbranched polyethyleneimine into deionized water and stirring evenly, adjusting the pH value, heating for reaction, centrifuging, washing, and drying to obtain the hyperbranched polyethyleneimine grafted silicon carbide nanowires.

4. The heat shrinkable tube according to claim 2, characterized in that: The preparation steps of the surface fluorinated silicon carbide nanowires include: adding silicon carbide nanowires and a fluorinated silane coupling agent into an ethanol aqueous solution, stirring evenly, adjusting pH, heating for reaction, centrifuging, washing, and drying to obtain the surface fluorinated silicon carbide nanowires.

5. The heat shrinkable tube according to claim 2, characterized in that: The silicon carbide nanowire has a diameter of 1-5 μm and a length of 50-100 μm.

6. The heat shrinkable tube according to claim 2, characterized in that: The molecular weight of the hyperbranched polyethyleneimine is 10000-11000.

7. The heat shrinkable tube according to claim 2, characterized in that: The mass ratio of the EVA to the silicon carbide nanowires is 3-3.5:

1.

8. The heat shrinkable tube according to claim 2, characterized in that: The mass ratio of the hyperbranched polyethyleneimine grafted silicon carbide nanowires to the surface fluorinated silicon carbide nanowires is 1-1.5:

1.

9. A process for preparing the heat shrinkable tube according to any one of claims 1 to 8, characterized in that: The preparation process comprises the following steps: weighing each component, mixing uniformly according to mass, extruding and molding, and then irradiating and expanding to obtain a heat shrinkable tube.

10. The process for preparing the heat shrinkable tube according to claim 9, characterized in that: The irradiation dose is 70-200 kGy.