High-temperature heat-stable PE (polyethylene) material and preparation process thereof

Abstract

The invention discloses a high-temperature heat-stable PE (polyethylene) material and a preparation process thereof, and belongs to the technical field of polyethylene materials. Comprising the following steps: vacuumizing a reactor, filling nitrogen for replacement, heating and baking the reactor in vacuum, cooling, introducing ethylene, heating at a constant temperature, adding modified olefin, a cocatalyst and diethyl zinc, magnetically stirring, dissolving the catalyst with toluene, and filling the dissolved catalyst into the reactor for polymerization reaction to prepare a modified polyethylene glue solution; taking the modified polyethylene glue solution, adding octadecanamide, mixing, heating, carrying out ultrasonic stirring, adding sorbitol, heating, and continuously carrying out ultrasonic stirring to prepare a preparation solution; adding the prepared solution into a twin-screw extruder for extrusion and granulation, carrying out compression molding, and cooling to obtain the PE material with high-temperature thermal stability. A highly branched polymer is formed in the ethylene polymerization process, so that the thermal stability of polyethylene is improved.

Description

Technical Field

[0001] This invention belongs to the field of polyethylene material technology, specifically relating to a high-temperature thermally stable PE material and its preparation process. Background Technology

[0002] Polyethylene (PE) is a thermoplastic resin produced by polymerizing ethylene. It is lightweight, corrosion-resistant, and has excellent mechanical strength. Because polyethylene is a high-molecular-weight compound polymerized from a large number of ethylene monomers, its molecular structure contains only carbon and hydrogen elements and lacks other functional groups. This results in weak bonding forces to resist decomposition at high temperatures. Under high-temperature conditions, the molecular chains of polyethylene are prone to breakage and a decrease in molecular weight. High temperatures intensify the vibration of the polyethylene molecular chains, increasing interchain steric hindrance and internal stress, thus leading to easy chain breakage. Furthermore, polyethylene is prone to oxidation at high temperatures, further triggering chain breakage and decomposition. Consequently, polyethylene has poor thermal stability at high temperatures.

[0003] During processing, the heat resistance of polyethylene has a significant impact on product quality and production efficiency. If the material has low heat resistance, it is prone to problems such as melting and cracking, and deformation, which affects the quality of the finished product. Improving the heat resistance of polyethylene can extend the service life of the material, reduce the need for frequent replacements, lower costs, and maintain the mechanical strength, electrical insulation properties, and chemical resistance of polyethylene, enabling it to operate normally under high-temperature conditions. Summary of the Invention

[0004] This invention discloses a high-temperature thermally stable PE material and its preparation process, belonging to the field of polyethylene material technology. The process includes the following steps: vacuuming a reactor, purging it with nitrogen, heating and baking the reactor under vacuum, cooling, introducing ethylene, heating at a constant temperature, adding modified olefins, a co-catalyst, and diethylzinc, magnetically stirring, dissolving the catalyst in toluene and adding it to the reactor for polymerization to obtain a modified polyethylene adhesive; taking the modified polyethylene adhesive, adding stearamide, mixing, heating, ultrasonically stirring, adding sorbitol, heating, and continuing ultrasonic stirring to obtain a preparative solution; taking the preparative solution and adding it to a twin-screw extruder for granulation, molding, and cooling to obtain the high-temperature thermally stable PE material.

[0005] The technical problem to be solved by this invention is to improve the high-temperature thermal stability of polyethylene materials.

[0006] The objective of this invention can be achieved through the following technical solutions: A process for preparing a high-temperature thermally stable PE material includes the following steps: (1) The reactor is evacuated and purged with nitrogen three times. The reactor is then heated and baked with an electric hot gun under vacuum. After cooling, ethylene is introduced and heated at a constant temperature. Modified olefin, co-catalyst, and diethylzinc are added. The mixture is magnetically stirred. The catalyst is dissolved in toluene and flushed into the reactor to carry out the polymerization reaction. Acidified ethanol is added to the reactor to terminate the reaction. After polymerization, the mixture is allowed to settle, stirred, filtered, and the filtrate is collected to obtain modified polyethylene adhesive. (2) Take the modified polyethylene adhesive, add stearamide, heat up, ultrasonically mix and stir, add sorbitol, heat up, continue ultrasonic mixing and stirring to obtain the preparative solution; (3) Take the preparative liquid and add it to a twin-screw extruder and extrude and granulate it at 170-200℃ to obtain particles. Then put the particles into a tablet press for molding and cooling to obtain the high-temperature thermally stable PE material.

[0007] As a preferred technical solution of the present invention, in step (1), the ratio of ethylene, modified olefin, co-catalyst, diethylzinc, toluene, catalyst, and acidified ethanol is 5-10 mol: 4-6 mol: 0.2-0.3 g: 0.05-0.08 g: 10-20 mL: 0.5-0.8 g: 20 mL; the catalyst is N,N'-bis[2,6-bis(diphenylmethyl)-4-methylphenyl]acenaphthene-1,2-diimide; the co-catalyst is tri-n-hexylaluminum; the acidified ethanol refers to acidification by adding 5 mL of hydrochloric acid to 15 mL of anhydrous ethanol, and the concentration of the hydrochloric acid is 0.5 g / mL.

[0008] As a preferred technical solution of the present invention, in step (1), the temperature of the constant temperature heating is 45-55℃; the time of the polymerization reaction is 5-10h; and the stirring time after the polymerization is completed is 1-2h.

[0009] As a preferred embodiment of the present invention, in step (1), the preparation of the modified olefin includes the following steps: Fumaric acid and ethanol were added to a reaction vessel and heated and stirred to dissolve under a nitrogen atmosphere. Hydroxyethyl sulfonic acid was then added, and the reaction was carried out under controlled temperature to obtain the modified olefin.

[0010] As a preferred embodiment of the present invention, the ratio of fumaric acid, hydroxyethyl sulfonic acid, and ethanol is 1-2 mol: 1.5-2.5 mol: 100-200 mL; the heating and stirring refers to stirring at 40-60°C for 5 min; the temperature-controlled reaction refers to reacting at 60°C for 30-50 min.

[0011] As a preferred technical solution of the present invention, in step (2), the mass ratio of the modified polyethylene adhesive, stearamide and sorbitol is 1-2:0.5-0.8:2-4.

[0012] As a preferred technical solution of the present invention, in step (2), the temperature rise after adding stearamide refers to the temperature rise to 60°C, and the ultrasonic mixing and stirring time after adding stearamide is 0.5-1h; the temperature rise after adding sorbitol refers to the temperature rise to 75-80°C, and the ultrasonic mixing and stirring time after adding sorbitol is 20-30min.

[0013] As a preferred technical solution of the present invention, in step (1), the temperature of heating and baking with an electric hot gun is 600°C and the baking time is 3 min; the cooling refers to cooling to room temperature; the magnetic stirring time is 1-2 h.

[0014] As a preferred technical solution of the present invention, in step (3), the molding pressure of the molding process is 5MPa and the molding temperature is 190℃.

[0015] A high-temperature thermally stable PE material prepared using the above-described preparation process.

[0016] The beneficial effects of this invention are: (1) The high-temperature thermally stable PE material and preparation process disclosed in this invention use N,N'-bis[2,6-bis(diphenylmethyl)-4-methylphenyl]acenaphthene-1,2-diimide as a catalyst to drive the modified olefin to perform chain shuttle during the ethylene polymerization process, activate ethylene and enable the modified olefin to form a coordination bond with ethylene, thereby realizing the chain transfer process, thereby initiating the alternating distribution and copolymerization of ethylene and modified olefin on the same polymer chain to form a highly branched polymer, increasing the difficulty of polyethylene molecular chain movement, and the highly branched structure hinders the mutual displacement between molecules, thereby improving the thermal stability of polyethylene.

[0017] (2) The high-temperature thermally stable PE material and preparation process disclosed in this invention introduces thermally stable sulfonyl functional groups to form a cyclic structure modified olefin, which restricts the free twisting and rotation of molecules, thereby reducing the kinetic energy of olefin molecules, increasing the intermolecular bonding force, further restricting the movement between molecules, reducing the mutual collision and twisting between molecules. After the movement between molecules is restricted, the modified olefin material has higher rigidity and fatigue resistance, can better withstand external stress and deformation, and improve the thermal stability of PE material at high temperature.

[0018] (3) The high-temperature thermally stable PE material and preparation process disclosed in this invention are achieved by combining polyethylene with the heat stabilizer stearamide. Due to the presence of polar groups in the stearamide molecule, the polarization degree of the molecule is enhanced. When the non-polar hydrocarbon chain on the polyethylene main chain approaches the stearamide molecule, it will be affected by the charge distribution of the stearamide molecule and thus be attracted by induction, so that the stearamide molecule is wrapped around the polyethylene. The entanglement of the molecular chain makes the spatial arrangement between polyethylene molecules more compact, which restricts the movement between polyethylene molecules at high temperature and improves the thermal stability of PE material at high temperature. Furthermore, due to the low surface tension of stearamide, it can form a dense and smooth coating layer on the polyethylene surface, reducing the energy state of the polyethylene surface. At the same time, the presence of the stearamide coating layer can provide more adsorption sites, allowing sorbitol nucleating agent molecules to be better adsorbed on the polyethylene backbone, increasing the energy barrier for intermolecular translocation, and improving the formation speed and degree of polyethylene crystallization. Sorbitol, as a nucleation point for crystallization during polyethylene extrusion molding, promotes the formation of polyethylene crystals, improves the physical properties of polyethylene and the efficiency of the extrusion molding process. Detailed Implementation

[0019] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with embodiments, is provided below.

[0020] Example 1 Preparation of modified olefins 1 mol of fumaric acid and 100 mL of ethanol were added to a reaction vessel and heated and stirred to dissolve under a nitrogen atmosphere. Then, 1.5 mol of hydroxyethyl sulfonic acid was added and the reaction was carried out at a controlled temperature to obtain the modified olefin. The heating and stirring referred to stirring at 40°C for 5 min and the temperature-controlled reaction referred to reacting at 60°C for 30 min.

[0021] Preparation of high-temperature thermally stable PE materials (1) The reactor was evacuated and purged with nitrogen three times. Then, the reactor was heated to 600°C for 3 minutes under vacuum and cooled to room temperature of 25°C. 5 mol of ethylene was introduced and heated at a constant temperature. 4 mol of modified olefin, 0.2 g of tri-n-hexyl aluminum, and 0.05 g of diethylzinc were added and magnetically stirred for 1 hour. 0.5 g of N,N”-bis[2,6-bis(diphenylmethyl)-4-methylphenyl]acenaphthene-1,2-diimide was dissolved in 10 mL of toluene and added to the reactor to carry out the polymerization reaction. 20 mL of acidified ethanol was added to the reactor to terminate the reaction. After polymerization, the mixture was allowed to settle, stirred for 1 hour, filtered, and the filtrate was collected to obtain modified polyethylene adhesive. The acidified ethanol refers to the acidification of 15 mL of anhydrous ethanol with 5 mL of hydrochloric acid, and the concentration of the hydrochloric acid is 0.5 g / mL. The constant temperature heating temperature is 45°C. The polymerization reaction time is 5 hours. The stirring time after polymerization is 1 hour. (2) Take 1 part by weight of the modified polyethylene adhesive, add 0.5 parts by weight of stearamide, heat up, ultrasonically mix and stir, add 2 parts by weight of sorbitol, heat up, continue ultrasonic mixing and stirring to obtain the preparative solution; the heating after adding stearamide refers to heating up to 60°C, and the ultrasonic mixing and stirring time after adding stearamide is 0.5h; the heating after adding sorbitol refers to heating up to 75°C, and the ultrasonic mixing and stirring time after adding sorbitol is 20min; (3) The preparative liquid is added to a twin-screw extruder and extruded and granulated at 170°C to obtain particles. Then the particles are placed in a tablet press for molding and cooled to obtain the high-temperature thermally stable PE material. The molding pressure is 5 MPa and the molding temperature is 190°C.

[0022] Example 2 Preparation of modified olefins 1.5 mol of fumaric acid and 150 mL of ethanol were added to a reaction vessel and heated and stirred to dissolve under a nitrogen atmosphere. Then, 2 mol of hydroxyethyl sulfonic acid was added and the reaction was carried out at a controlled temperature to obtain the modified olefin. The heating and stirring referred to stirring at 50°C for 5 min and the temperature-controlled reaction referred to reacting at 60°C for 40 min.

[0023] Preparation of high-temperature thermally stable PE materials (1) The reactor was evacuated and purged with nitrogen three times. Then, under vacuum, the reactor was heated to 600°C for 3 minutes using a hot gun. After cooling to room temperature (25°C), 7 mol of ethylene was introduced, and the reactor was heated at a constant temperature. Then, 5 mol of modified olefin, 0.25 g of tri-n-hexyl aluminum, and 0.065 g of diethylzinc were added. The mixture was magnetically stirred for 1.5 h. Finally, 0.6 g of N,N'-bis[ 2,6-Bis(diphenylmethyl)-4-methylphenyl]acenaphthene-1,2-diimide was dissolved and added to the reactor for polymerization. 20 mL of acidified ethanol was added to the reactor to terminate the reaction. After polymerization, the mixture was allowed to settle, stirred for 1.5 h, filtered, and the filtrate was collected to obtain modified polyethylene adhesive. The acidified ethanol refers to the acidification of 15 mL of anhydrous ethanol with 5 mL of hydrochloric acid, where the concentration of hydrochloric acid was 0.5 g / mL. The constant temperature heating was 50 °C. The polymerization reaction time was 7 h. The stirring time after polymerization was 1.5 h. (2) Take 1.5 parts by weight of the modified polyethylene adhesive, add 0.6 parts by weight of stearamide, heat up, ultrasonically mix and stir, add 3 parts by weight of sorbitol, heat up, continue ultrasonic mixing and stirring to obtain the preparative solution; the heating after adding stearamide refers to heating up to 60°C, and the ultrasonic mixing and stirring time after adding stearamide is 0.7h; the heating after adding sorbitol refers to heating up to 78°C, and the ultrasonic mixing and stirring time after adding sorbitol is 25min; (3) The preparative liquid is added to a twin-screw extruder and extruded and granulated at 190°C to obtain particles. Then the particles are placed in a tablet press for molding and cooled to obtain the high-temperature thermally stable PE material. The molding pressure is 5 MPa and the molding temperature is 190°C.

[0024] Example 3 Preparation of modified olefins 2 mol of fumaric acid and 200 mL of ethanol were added to a reaction vessel and heated and stirred under a nitrogen atmosphere to dissolve them. Then, 2.5 mol of hydroxyethyl sulfonic acid was added and the reaction was carried out at a controlled temperature to obtain the modified olefin. The heating and stirring referred to stirring at 60°C for 5 min. The controlled temperature reaction referred to reacting at 60°C for 50 min.

[0025] Preparation of high-temperature thermally stable PE materials (1) The reactor was evacuated and purged with nitrogen three times. Then, the reactor was heated to 600°C for 3 minutes under vacuum and cooled to room temperature of 25°C. 10 mol of ethylene was introduced and heated at a constant temperature. 6 mol of modified olefin, 0.3 g of tri-n-hexyl aluminum, and 0.08 g of diethylzinc were added and magnetically stirred for 2 hours. 0.8 g of N,N'-bis[2,6-bis(diphenylmethyl)-4-methylphenyl]acenaphthene-1,2-diimide was dissolved in 20 mL of toluene and added to the reactor to carry out the polymerization reaction. 20 mL of acidified ethanol was added to the reactor to terminate the reaction. After polymerization, the mixture was allowed to settle, stirred for 2 hours, filtered, and the filtrate was collected to obtain modified polyethylene adhesive. The acidified ethanol refers to the acidification of 15 mL of anhydrous ethanol with 5 mL of hydrochloric acid, and the concentration of the hydrochloric acid is 0.5 g / mL. The constant temperature heating temperature is 55°C. The polymerization reaction time is 10 hours. The stirring time after polymerization is 2 hours. (2) Take 2 parts by weight of the modified polyethylene adhesive, add 0.8 parts by weight of stearamide, heat up, ultrasonically mix and stir, add 4 parts by weight of sorbitol, heat up, continue ultrasonic mixing and stirring to obtain the preparative solution; the heating after adding stearamide refers to heating up to 60°C, and the ultrasonic mixing and stirring time after adding stearamide is 1 hour; the heating after adding sorbitol refers to heating up to 80°C, and the ultrasonic mixing and stirring time after adding sorbitol is 30 minutes. (3) The preparative liquid is added to a twin-screw extruder and extruded and granulated at 200°C to obtain particles. Then the particles are placed in a tablet press for molding and cooled to obtain the high-temperature thermally stable PE material. The molding pressure is 5 MPa and the molding temperature is 190°C.

[0026] Comparative Example 1 Preparation of high-temperature thermally stable PE materials (1) The reactor was evacuated and purged with nitrogen three times. Then, the reactor was heated to 600°C for 3 minutes under vacuum and cooled to room temperature of 25°C. 9 mol of ethylene was introduced and the reactor was heated at a constant temperature. 0.2 g of tri-n-hexyl aluminum and 0.05 g of diethyl zinc were added and the reactor was magnetically stirred for 1 hour. 0.5 g of N,N'-bis[2,6-bis(diphenylmethyl)-4-methylphenyl]acenaphthene-1,2-diimide was dissolved in 10 mL of toluene and added to the reactor to carry out the polymerization reaction. 20 mL of acidified ethanol was added to the reactor to terminate the reaction. After polymerization, the mixture was allowed to settle, stirred for 1 hour, filtered, and the filtrate was collected to obtain polyethylene adhesive. The acidified ethanol refers to the acidification of 15 mL of anhydrous ethanol with 5 mL of hydrochloric acid, and the concentration of the hydrochloric acid was 0.5 g / mL. The constant temperature heating temperature was 45°C. The polymerization reaction time was 5 hours. The stirring time after polymerization was 1 hour. (2) Take 1 part by weight of the polyethylene adhesive, add 0.5 parts by weight of stearamide, heat up, ultrasonically mix and stir, add 2 parts by weight of sorbitol, heat up, continue ultrasonic mixing and stirring to obtain the preparative solution; the heating after adding stearamide refers to heating up to 60°C, and the ultrasonic mixing and stirring time after adding stearamide is 0.5h; the heating after adding sorbitol refers to heating up to 75°C, and the ultrasonic mixing and stirring time after adding sorbitol is 20min; (3) The preparative liquid is added to a twin-screw extruder and extruded and granulated at 170°C to obtain particles. Then the particles are placed in a tablet press for molding and cooled to obtain the high-temperature thermally stable PE material. The molding pressure is 5 MPa and the molding temperature is 190°C.

[0027] Comparative Example 2 Preparation of modified olefins 1 mol of fumaric acid and 100 mL of ethanol were added to a reaction vessel and heated and stirred to dissolve under a nitrogen atmosphere. Then, 1.5 mol of hydroxyethyl sulfonic acid was added and the reaction was carried out at a controlled temperature to obtain the modified olefin. The heating and stirring referred to stirring at 40°C for 5 min and the temperature-controlled reaction referred to reacting at 60°C for 30 min.

[0028] Preparation of high-temperature thermally stable PE materials (1) The reactor was evacuated and purged with nitrogen three times. Then, the reactor was heated to 600°C for 3 minutes under vacuum and cooled to room temperature of 25°C. 5 mol of ethylene was introduced and the reactor was heated at a constant temperature. 4 mol of modified olefin, 0.2 g of tri-n-hexyl aluminum, and 0.05 g of diethylzinc were added and the reactor was magnetically stirred for 1 hour. 0.5 g of N,N'-bis[2,6-bis(diphenylmethyl)-4-methylphenyl]acenaphthene-1,2-diimide was dissolved in 10 mL of toluene and added to the reactor to carry out the polymerization reaction. 20 mL of acidified ethanol was added to the reactor to terminate the reaction. After polymerization, the reactor was allowed to settle, stirred for 1 hour, filtered, and the filtrate was collected to obtain modified polyethylene adhesive. The acidified ethanol refers to the acidification of 15 mL of anhydrous ethanol with 5 mL of hydrochloric acid, and the concentration of the hydrochloric acid is 0.5 g / mL. The constant temperature heating temperature was 45°C. The polymerization reaction time was 5 hours. The stirring time after polymerization was 1 hour. (2) Take 1 part by weight of the modified polyethylene adhesive, add 2 parts by weight of sorbitol, heat up, and continue ultrasonic mixing and stirring to prepare a preparative solution; the heating after adding sorbitol refers to heating up to 75°C, and the ultrasonic mixing and stirring time after adding sorbitol is 20 min. (3) The preparative liquid is added to a twin-screw extruder and extruded and granulated at 170°C to obtain particles. Then the particles are placed in a tablet press for molding and cooled to obtain the high-temperature thermally stable PE material. The molding pressure is 5 MPa and the molding temperature is 190°C.

[0029] Comparative Example 3 Preparation of modified olefins 1 mol of fumaric acid and 100 mL of ethanol were added to a reaction vessel and heated and stirred to dissolve under a nitrogen atmosphere. Then, 1.5 mol of hydroxyethyl sulfonic acid was added and the reaction was carried out at a controlled temperature to obtain the modified olefin. The heating and stirring referred to stirring at 40°C for 5 min and the temperature-controlled reaction referred to reacting at 60°C for 30 min.

[0030] Preparation of high-temperature thermally stable PE materials (1) The reactor was evacuated and purged with nitrogen three times. Then, the reactor was heated to 600°C for 3 minutes under vacuum and cooled to room temperature of 25°C. 5 mol of ethylene was introduced and the reactor was heated at a constant temperature. 4 mol of modified olefin, 0.2 g of tri-n-hexyl aluminum, and 0.05 g of diethylzinc were added and the reactor was magnetically stirred for 1 hour. 0.5 g of N,N'-bis[2,6-bis(diphenylmethyl)-4-methylphenyl]acenaphthene-1,2-diimide was dissolved in 10 mL of toluene and added to the reactor to carry out the polymerization reaction. 20 mL of acidified ethanol was added to the reactor to terminate the reaction. After polymerization, the reactor was allowed to settle, stirred for 1 hour, filtered, and the filtrate was collected to obtain modified polyethylene adhesive. The acidified ethanol refers to the acidification of 15 mL of anhydrous ethanol with 5 mL of hydrochloric acid, and the concentration of the hydrochloric acid is 0.5 g / mL. The constant temperature heating temperature was 45°C. The polymerization reaction time was 5 hours. The stirring time after polymerization was 1 hour. (2) Take 1 part by weight of the modified polyethylene adhesive, add 0.5 parts by weight of stearamide, heat up, and ultrasonically mix and stir to prepare a preparative solution; the heating after adding stearamide refers to heating up to 60°C, and the ultrasonic mixing and stirring time after adding stearamide is 0.5h. (3) The preparative liquid is added to a twin-screw extruder and extruded and granulated at 170°C to obtain particles. Then the particles are placed in a tablet press for molding and cooled to obtain the high-temperature thermally stable PE material. The molding pressure is 5 MPa and the molding temperature is 190°C.

[0031] Performance testing Perform dimensional stability testing according to the following method; injection mold the prepared PE material. After cooling for 24 hours, the sample was placed in a 100℃ oven for 8 hours. After being taken out and cooled to room temperature, the changes in length dimension before and after being placed in the oven were recorded. Thermal stability tests were conducted in accordance with standard GB / T 19466.6-2009.

[0032] The PE materials obtained in Examples 1-3 and Comparative Examples 1-3 (prepared based on Example 1) were subjected to performance tests according to the above standards. The test results are shown in Table 1 below: Table 1 As shown in Table 1, the thermal stability of Comparative Example 1 is significantly lower than that of Example 1, and the thermal stability of Comparative Examples 2 and 3 is lower than that of Example 1. Furthermore, the thermal stability of Comparative Example 3 is better than that of Comparative Example 2.

[0033] Note: The N,N'-bis[2,6-bis(diphenylmethyl)-4-methylphenyl]acenaphthene-1,2-diimide involved in this application are all derived from Shanghai Karum Biochemical Technology Co., Ltd.

[0034] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A preparation process for a high-temperature thermally stable PE material, characterized in that, Includes the following steps: (1) The reactor is evacuated and purged with nitrogen three times. The reactor is then heated and baked with an electric hot gun under vacuum. After cooling, ethylene is introduced and heated at a constant temperature. Modified olefin, co-catalyst, and diethylzinc are added. The mixture is magnetically stirred. The catalyst is dissolved in toluene and flushed into the reactor to carry out the polymerization reaction. Acidified ethanol is added to the reactor to terminate the reaction. After polymerization, the mixture is allowed to settle, stirred, filtered, and the filtrate is collected to obtain modified polyethylene adhesive. (2) Take the modified polyethylene adhesive, add stearamide, heat up, ultrasonically mix and stir, add sorbitol, heat up, continue ultrasonic mixing and stirring to obtain the preparative solution; (3) Take the preparative liquid and add it to a twin-screw extruder and extrude and granulate it at 170-200℃ to obtain particles. Then put the particles into a tablet press for molding and cooling to obtain a high-temperature thermally stable PE material.

2. The preparation process of a high-temperature thermally stable PE material according to claim 1, characterized in that, In step (1), the ratio of ethylene, modified olefin, co-catalyst, diethylzinc, toluene, catalyst, and acidified ethanol is 5-10 mol: 4-6 mol: 0.2-0.3 g: 0.05-0.08 g: 10-20 mL: 0.5-0.8 g: 20 mL; the catalyst is N,N'-bis[2,6-bis(diphenylmethyl)-4-methylphenyl]acenaphthene-1,2-diimide; the co-catalyst is tri-n-hexylaluminum; the acidified ethanol refers to acidification by adding 5 mL of hydrochloric acid to 15 mL of anhydrous ethanol, and the concentration of the hydrochloric acid is 0.5 g / mL.

3. The preparation process of a high-temperature thermally stable PE material according to claim 1, characterized in that, In step (1), the constant temperature heating temperature is 45-55℃; the polymerization reaction time is 5-10h; and the stirring time after the polymerization is completed is 1-2h.

4. The preparation process of a high-temperature thermally stable PE material according to claim 1, characterized in that, In step (1), the preparation of the modified olefin includes the following steps: Fumaric acid and ethanol were added to a reaction vessel and heated and stirred to dissolve under a nitrogen atmosphere. Hydroxyethyl sulfonic acid was then added, and the reaction was carried out under controlled temperature to obtain the modified olefin.

5. The preparation process of a high-temperature thermally stable PE material according to claim 4, characterized in that, The ratio of fumaric acid, hydroxyethyl sulfonic acid, and ethanol is 1-2 mol: 1.5-2.5 mol: 100-200 mL; the heating and stirring refers to stirring at 40-60℃ for 5 min; the temperature-controlled reaction refers to reacting at 60℃ for 30-50 min.

6. The preparation process of a high-temperature thermally stable PE material according to claim 1, characterized in that, In step (2), the mass ratio of the modified polyethylene adhesive, stearamide, and sorbitol is 1-2:0.5-0.8:2-4.

7. The preparation process of a high-temperature thermally stable PE material according to claim 1, characterized in that, In step (2), the temperature rise after adding stearamide refers to raising the temperature to 60°C, and the ultrasonic mixing time after adding stearamide is 0.5-1h; the temperature rise after adding sorbitol refers to raising the temperature to 75-80°C, and the ultrasonic mixing time after adding sorbitol is 20-30min.

8. The preparation process of a high-temperature thermally stable PE material according to claim 1, characterized in that, In step (1), the temperature of the electric heating gun is 600℃ and the baking time is 3 minutes; the cooling refers to cooling to room temperature; the magnetic stirring time is 1-2 hours.

9. The preparation process of a high-temperature thermally stable PE material according to claim 1, characterized in that, In step (3), the molding pressure is 5 MPa and the molding temperature is 190°C.

10. A high-temperature thermally stable PE material prepared by the preparation process according to any one of claims 1-9.

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