A method for preparing hyperbranched polyethylene and its application

Abstract

This invention relates to the application of hypergravity technology in coordination polymerization, and discloses a method for preparing hyperbranched polyethylene and its application. The method includes: (1) carrying out coordination polymerization of ethylene monomer, solvent, catalyst solution, and auxiliary catalyst solution under hypergravity conditions; and (2) removing the monomer, washing, separating, and drying the reaction product obtained in step (1). By controlling the hypergravity level, reactant ratio, reaction temperature, and pressure, this invention can obtain high-quality hyperbranched polyethylene products with a number-average molecular weight of 1000-1500000 and a molecular weight distribution index of 1.2-2.5. Compared with reactions in ordinary polymerization reactors, the production efficiency is significantly improved, and the product has a higher molecular weight and a narrower molecular weight distribution.

Description

Technical Field

[0001] This invention relates to the application of hypergravity technology in coordination polymerization reactions, specifically to a method for preparing and applying hyperbranched polyethylene. Background Technology

[0002] Hyperbranched polyethylene is typically prepared by solution polymerization of a single ethylene monomer in a medium such as hexane, catalyzed by an α-diimide post-transition metal catalyst. Hyperbranched polyethylene dissolves in solvents such as hexane to form a solution system. Given the significant influence of heat transfer, mass transfer, and micromixing during the polymerization of hyperbranched polyethylene, enhancing these aspects is crucial for the polymerization reaction. Currently, the preparation of olefin polymers generally employs traditional stirred polymerization, which results in poor micromixing, a long residence time of materials in the reactor (30-60 min), making it difficult to match with the polymerization rate. Furthermore, the reaction equipment is large, requires a large floor space, and is costly.

[0003] The hypergravity technology developed in recent years has revolutionized traditional mass transfer methods. Its core lies in conducting liquid-liquid, liquid-solid, and gas-liquid mass transfer processes within a hypergravity reactor. This significantly enhances mass transfer and micro-mixing processes, increasing the mass transfer coefficient and mixing rate by 1-3 orders of magnitude compared to traditional static (under gravity) mass transfer and micro-mixing processes. Hypergravity reactor devices have been disclosed in CN1461731A, CN100462303C, and CN109967013B, among others. However, the application of hypergravity technology in coordination polymerization reactions has not yet been reported. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems of poor micro-mixing, long residence time of materials in the reactor, difficulty in matching the polymerization rate, large footprint and high cost in the preparation of olefin polymers in the prior art. This invention provides a method for preparing hyperbranched polyethylene and its application. The average residence time of materials in the hypergravity reactor in this preparation method can be significantly shortened, resulting in low energy consumption, high production efficiency and low cost.

[0005] To achieve the above objectives, the present invention provides a method for preparing hyperbranched polyethylene, the method comprising the following steps:

[0006] (1) Ethylene monomer, solvent, catalyst and auxiliary catalyst were subjected to coordination polymerization reaction under hypergravity conditions in a hypergravity reactor;

[0007] (2) The reaction product obtained in step (1) is subjected to monomer removal, washing, separation and drying.

[0008] Preferably, in step (1), the catalyst is a diimine complex of a post-transition metal.

[0009] More preferably, the later transition metal is nickel and / or palladium.

[0010] Preferably, in step (1), the auxiliary catalyst is selected from one or more of aluminoxane, alkylaluminum and alkylaluminum chloride.

[0011] More preferably, the aluminum oxane is selected from one or more of methylaluminoxane, triisobutylaluminum-modified methylaluminoxane, ethylaluminoxane, and isobutylaluminoxane.

[0012] More preferably, the alkylaluminum is selected from one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, and tri-n-octylaluminum.

[0013] More preferably, the alkylaluminum chloride is selected from one or more of dimethylaluminum chloride, diethylaluminum chloride, ethylaluminum dichloride, and trichlorotriethylaluminum.

[0014] Preferably, in step (1), the molar ratio of the auxiliary catalyst to the catalyst is 100-4000:1, more preferably 400-1000:1, based on the auxiliary catalyst and the metal elements contained in the catalyst.

[0015] Preferably, in step (1), the conditions for the coordination polymerization reaction include: a temperature of 0℃-150℃, preferably 50-80℃; a pressure of 0.1-5MPa, preferably 0.5-1.5MPa; a hypergravity level of 10-800g, preferably 200-600g; and a time of 2-30min, preferably 5-15min.

[0016] Preferably, in step (1), the ingredient is selected from C5-C. 12 Aliphatic alkanes and / or aromatic compounds.

[0017] More preferably, the C5-C 12 Aliphatic alkanes are selected from one or more of pentane, hexane, heptane, octane, and cyclohexane.

[0018] More preferably, the aromatic compound is toluene.

[0019] Preferably, the raw materials for the coordination polymerization reaction also contain comonomers.

[0020] More preferably, the comonomer is an α-olefin and / or a polar α-olefin containing heteroatoms.

[0021] More preferably, the α-olefin is selected from one or more of propylene, 1-butene, 1-hexene, 1-octene, and 1-dodecene.

[0022] More preferably, the polar α-olefin containing heteroatoms is selected from one or more of methyl 10-enoate, undecenoic acid, undecenoyl alcohol, 6-chlorohexene, methyl acrylate, ethyl acrylate, propylene acetate, and methyl norborneol.

[0023] Preferably, the raw materials for the coordination polymerization reaction also contain a chain transfer agent.

[0024] More preferably, the chain transfer agent is hydrogen and / or triethylzinc.

[0025] A second aspect of the present invention provides hyperbranched polyethylene prepared by the method described above.

[0026] Preferably, the number-average molecular weight of the hyperbranched polyethylene is 1,000-1,500,000, more preferably 20,000-50,000; and the molecular weight distribution index is 1.2-2.5.

[0027] A third aspect of the present invention provides the application of the hyperbranched polyethylene described above in photovoltaic films.

[0028] The main advantages of the present invention through the above technical solution are as follows:

[0029] (1) This invention employs a hypergravity reactor. Due to the high-speed rotation of the rotor within the reactor, a stable hypergravity environment is formed, with a hypergravity level reaching tens or even hundreds of times greater than the natural gravitational acceleration. Under this hypergravity environment, the mass and heat transfer processes are further enhanced, thereby rapidly achieving a micro-mixing state. Compared with traditional stirred polymerization reactions, the average residence time of materials in the hypergravity reactor can be significantly shortened, resulting in lower energy consumption, higher production efficiency, and lower cost.

[0030] (2) By controlling the ratio of reactants, reaction temperature and hypergravity level, the present invention can obtain hyperbranched polyethylene products with a number average molecular weight of 1,000-1,500,000 and a molecular weight distribution index of 1.2-2.5. Detailed Implementation

[0031] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0032] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0033] This invention provides a method for preparing hyperbranched polyethylene, the method comprising the following steps:

[0034] (1) Ethylene monomer, solvent, catalyst and auxiliary catalyst were subjected to coordination polymerization reaction under hypergravity conditions in a hypergravity reactor;

[0035] (2) The reaction product obtained in step (1) is subjected to monomer removal, washing, separation and drying.

[0036] In the method described in this invention, in a specific embodiment, the coordination polymerization reaction is carried out in a hypergravity reactor. Specifically, the coordination polymerization reaction is completed in contact within the packing layer, baffle channel, spiral channel, or disc of the hypergravity reactor. By employing a hypergravity reactor, the mass and heat transfer processes are further enhanced, thereby rapidly achieving a micro-mixing state. Using the method described in this invention results in high production efficiency and high yield.

[0037] In the method described in this invention, the hypergravity reactor is selected from one or more of the following: rotating packed bed, baffle type, spiral channel, rotating disc, stator-rotor hypergravity rotating device, and ultrasonic-microwave coupled hypergravity device.

[0038] In the method described in this invention, in order to obtain high molecular weight hyperbranched polyethylene, the ratio of reactants can be limited to an appropriate range. In a specific embodiment, in step (1), the molar ratio of the auxiliary catalyst to the catalyst is 100-4000:1, preferably 400-1000:1, based on the auxiliary catalyst and the metal elements contained in the catalyst.

[0039] In a preferred embodiment, the catalyst solution concentration is 0.1-2 g / L, and the auxiliary catalyst solution concentration is 0.5-2 mol / L.

[0040] In the method described in this invention, in step (1), the catalyst is a diimine complex of a later transition metal. In a preferred embodiment, the later transition metal is nickel and / or palladium.

[0041] In this invention, in step (1), in a specific embodiment, the auxiliary catalyst is selected from one or more of aluminoxane, alkylaluminum and alkylaluminum chloride.

[0042] In a preferred embodiment, the aluminum oxane is selected from one or more of methylaluminoxane, triisobutylaluminum-modified methylaluminoxane, ethylaluminoxane, and isobutylaluminoxane.

[0043] In a preferred embodiment, the alkylaluminum is selected from one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, and tri-n-octylaluminum.

[0044] In a preferred embodiment, the alkylaluminum chloride is selected from one or more of dimethylaluminum chloride, diethylaluminum chloride, ethylaluminum dichloride, and trichlorotriethylaluminum.

[0045] In this invention, in step (1), the solvent can be a conventional choice for those skilled in the art, and the solvent is selected from C5-C. 12 Aliphatic alkanes and / or aromatic compounds.

[0046] In a further preferred embodiment, the C5-C 12 Aliphatic alkanes are selected from one or more of pentane, hexane, heptane, octane, and cyclohexane.

[0047] In a further preferred embodiment, the aromatic compound is toluene.

[0048] In this invention, in step (1), the raw materials for coordination polymerization reaction may also contain comonomers according to the reaction requirements. In a specific embodiment, the comonomers are α-olefins and / or polar α-olefins containing heteroatoms.

[0049] In a further preferred embodiment, the α-olefin is selected from one or more of propylene, 1-butene, 1-hexene, 1-octene, and 1-dodecene.

[0050] In a further preferred embodiment, the heteroatom in the heteroatom-containing polar α-olefin can be an oxygen atom or a chlorine atom. Specifically, the heteroatom-containing polar α-olefin is selected from one or more of methyl 10-enoate, undecenoic acid, undecenoyl alcohol, 6-chlorohexene, methyl acrylate, ethyl acrylate, propylene acetate, and methyl norborneol.

[0051] In the method described in this invention, in step (1), the raw materials for coordination polymerization reaction may also contain a chain transfer agent, which is selected from hydrogen and / or triethylzinc, depending on the reaction requirements.

[0052] In the method described in this invention, in order to obtain high-quality and high-yield hyperbranched polyethylene, the conditions of the coordination polymerization reaction can be restricted. In a specific embodiment, in step (1), the conditions of the coordination polymerization reaction include: temperature of 0℃-150℃, preferably 50-80℃; pressure of 0.1-5MPa, preferably 0.5-1.5MPa; hypergravity level of 10-800g, preferably 200-600g; and time of 2-30min, preferably 5-15min.

[0053] In this invention, the hypergravity level refers to the magnitude of the centrifugal acceleration generated by the rotor rotation in the hypergravity reactor, usually expressed as a multiple of the gravitational acceleration g, and is mainly related to the rotor's rotational speed and its inner and outer diameters. The hypergravity level g can be expressed by the following formula:

[0054]

[0055] In the formula: n is the rotor speed per minute; r1 and r2 are the inner and outer diameters of the rotor, respectively.

[0056] In this invention, the treatment in step (2) specifically includes: after the reaction in step (1) is completed, the product in step (1) is demonomerized, then washed with water or ethanol solution, then separated by precipitation or flash evaporation, dried, and finally extruded and granulated to obtain hyperbranched polyethylene.

[0057] In the method described in this invention, in step (2), in order to remove unpolymerized monomers, the product in step (1) can be subjected to monomer removal treatment. In a specific embodiment, monomer removal is carried out under conditions below the boiling point of the solvent.

[0058] According to a first embodiment of the present invention, the preparation method of hyperbranched polyethylene of the present invention includes the following steps: (1) carrying out coordination polymerization reaction of ethylene monomer, solvent, catalyst solution and auxiliary catalyst in a hypergravity reactor under hypergravity conditions; (2) removing monomers, washing, separating and drying the reaction product obtained in step (1); in step (1), the catalyst is a diimine complex of a post-transition metal; preferably, the post-transition metal is nickel and / or palladium.

[0059] According to a second embodiment of the present invention, the preparation method of hyperbranched polyethylene of the present invention includes the following steps: (1) performing coordination polymerization reaction of ethylene monomer, solvent, catalyst solution and auxiliary catalyst in a hypergravity reactor under hypergravity conditions; (2) removing monomers, washing, separating and drying the reaction product obtained in step (1); in step (1), the catalyst is a diimine complex of a post-transition metal; the post-transition metal is nickel and / or palladium; in step (1), the auxiliary catalyst is selected from one or more of aluminoxane, alkylaluminum and alkylaluminum chloride.

[0060] According to a third embodiment of the present invention, the preparation method of hyperbranched polyethylene of the present invention includes the following steps: (1) performing coordination polymerization reaction of ethylene monomer, solvent, catalyst solution and auxiliary catalyst in a hypergravity reactor under hypergravity conditions; (2) removing monomers, washing, separating and drying the reaction product obtained in step (1); in step (1), the catalyst is a diimine complex of a post-transition metal; the post-transition metal is nickel and / or palladium; in step (1), the auxiliary catalyst is selected from one or more of aluminoxane, alkylaluminum and alkylaluminum chloride; in step (1), the molar ratio of the auxiliary catalyst to the catalyst is 400-1000:1 based on the metal elements contained in the auxiliary catalyst and the catalyst; in step (1), the conditions of the coordination polymerization reaction include: temperature of 0℃-150℃; pressure of 0.1-5MPa; hypergravity level of 10-800g; time of 5-15min.

[0061] According to a fourth embodiment of the present invention, the preparation method of hyperbranched polyethylene of the present invention includes the following steps: (1) performing coordination polymerization reaction of ethylene monomer, solvent, catalyst solution and auxiliary catalyst in a hypergravity reactor under hypergravity conditions; (2) removing monomers, washing, separating and drying the reaction product obtained in step (1); in step (1), the catalyst is a diimine complex of a post-transition metal; the post-transition metal is nickel and / or palladium; in step (1), the auxiliary catalyst is selected from one or more of aluminoxane, alkylaluminum and alkylaluminum chloride; in step (1), the molar ratio of the auxiliary catalyst to the catalyst is 400-1000:1 based on the metal elements contained in the auxiliary catalyst and the catalyst; in step (1), the conditions of the coordination polymerization reaction include: temperature of 0℃-150℃; pressure of 0.1-5MPa; hypergravity level of 10-800g; time of 5-15min; in step (1), the solvent is selected from C5-C 12 Aliphatic alkanes and / or aromatic compounds; the raw materials for coordination polymerization reactions also contain comonomers.

[0062] According to a fifth embodiment of the present invention, the preparation method of hyperbranched polyethylene of the present invention includes the following steps: (1) performing coordination polymerization reaction of ethylene monomer, solvent, catalyst solution and auxiliary catalyst in a hypergravity reactor under hypergravity conditions; (2) removing monomers, washing, separating and drying the reaction product obtained in step (1); in step (1), the catalyst is a diimine complex of a post-transition metal; the post-transition metal is nickel and / or palladium; in step (1), the auxiliary catalyst is selected from one or more of aluminoxane, alkylaluminum and alkylaluminum chloride; in step (1), the molar ratio of the auxiliary catalyst to the catalyst is 400-1000:1 based on the metal elements contained in the auxiliary catalyst and the catalyst; in step (1), the conditions of the coordination polymerization reaction include: temperature of 0℃-150℃; pressure of 0.1-5MPa; hypergravity level of 10-800g; time of 5-15min; in step (1), the solvent is selected from C5-C 12 Aliphatic alkanes and / or aromatic compounds; the raw materials for coordination polymerization also contain comonomers; the raw materials for coordination polymerization also contain chain transfer agents.

[0063] A second aspect of the present invention provides hyperbranched polyethylene prepared by the method described above. The hyperbranched polyethylene has a number-average molecular weight of 1,000-1,500,000, preferably 20,000-50,000; and a molecular weight distribution index of 1.2-2.5.

[0064] A third aspect of the present invention provides the application of the hyperbranched polyethylene described above in photovoltaic films.

[0065] The hyperbranched polyethylene film prepared by the method described in this invention has good transparency (≥90%).

[0066] The present invention will be described in detail below through examples. Unless otherwise specified, all methods are conventional in the art. Unless otherwise specified, the experimental materials used in the following examples can be purchased from reagent suppliers.

[0067] Example 1

[0068] In the post-transition metal diimide complexes described in Examples 1-2 of this invention, the nickel metal is Ni1 as described in patent application CN116239494A.

[0069] After the 5L hypergravity reactor was subjected to anhydrous and oxygen-free treatment, 3L of hexane was added, followed by a toluene solution of 0.02g of nickel diimide complex and a 1mol / L 4mL hexane solution of trichlorotriethyldialuminum. Ethylene was continuously introduced, and the gas inlet rate was controlled to maintain the pressure inside the reactor at 0.8MPa. The hypergravity level was 200g, and the reaction was carried out at 60℃ for 10min. After the reaction was completed, the product was separated, washed with ethanol solution, and then subjected to monomer removal, drying, and finally extrusion granulation to obtain hyperbranched polyethylene.

[0070] Example 2

[0071] The method was carried out according to Example 1, except that the hypergravity level was 500g. The specific method is as follows:

[0072] After the 5L hypergravity reactor was subjected to anhydrous and oxygen-free treatment, 3L of hexane was added, followed by a toluene solution of 0.02g of nickel diimide complex and a 1mol / L 4mL hexane solution of trichlorotriethyldialuminum. Ethylene was continuously introduced, and the gas inlet rate was controlled to maintain the pressure inside the reactor at 0.8MPa. The hypergravity level was 500g, and the reaction was carried out at 60℃ for 10min. After the reaction was completed, the product was separated, washed with ethanol solution, and then subjected to monomer removal, drying, and finally extrusion granulation to obtain hyperbranched polyethylene.

[0073] Example 3

[0074] In the post-transition metal diimine complex described in Example 3 of this invention, the nickel metal is Ni2 as described in patent application CN116239494A.

[0075] After the 5L hypergravity reactor was treated to be anhydrous and oxygen-free, 3L of hexane was added, followed by a toluene solution of 0.02g of nickel diimide complex and a 1mol / L 4mL trichlorotriethylaluminum hexane solution. Ethylene was continuously introduced, and the gas inlet rate was controlled to maintain the pressure inside the reactor at 1MPa. The hypergravity level was 200g, and the reaction was carried out at 75℃ for 10min. After the reaction was completed, the product was separated, washed with ethanol solution, and then subjected to monomer removal, drying, and finally extrusion granulation to obtain hyperbranched polyethylene.

[0076] Example 4

[0077] In Example 4 of this invention, the nickel in the post-transition metal diimine complex is Ni3 as described in patent application CN116239494A.

[0078] After the 5L hypergravity reactor was subjected to anhydrous and oxygen-free treatment, 3L of hexane was added, followed by a toluene solution of 0.02g of nickel diimide complex and a 2mol / L 4mL trichlorotriethylaluminum hexane solution. Ethylene was continuously introduced, and the gas inlet rate was controlled to maintain the pressure inside the reactor at 1.2MPa. The hypergravity level was 200g, and the reaction was carried out at 80℃ for 10min. After the reaction was completed, the product was separated, washed with ethanol solution, and then subjected to monomer removal, drying, and finally extrusion granulation to obtain hyperbranched polyethylene.

[0079] Example 5

[0080] In the post-transition metal diimine complex described in Example 5 of this invention, the nickel metal is Ni4 as described in patent application CN116239494A.

[0081] After the 5L hypergravity reactor was treated to be anhydrous and oxygen-free, 3L of hexane was added, followed by a toluene solution of 0.02g of nickel diimide complex and a 2mol / L 4mL trichlorotriethylaluminum hexane solution. Ethylene was continuously introduced, and the gas inlet rate was controlled to maintain the pressure inside the reactor at 2MPa. The hypergravity level was 50g, and the reaction was carried out at 85℃ for 10min. After the reaction was completed, the product was separated, washed with ethanol solution, then subjected to monomer removal and drying, and finally extruded and granulated to obtain hyperbranched polyethylene.

[0082] Example 6

[0083] The post-transition metal diimide complex described in Example 6 of this invention adopts N,N-bis(2,6-diphenylmethyl-4-hydroxyphenyl)butane-2,3-diimide nickel(II) dibromide from patent CN109608507B.

[0084] After the 5L hypergravity reactor was treated to be anhydrous and oxygen-free, 3L of hexane was added, followed by a toluene solution of 0.02g of nickel diimide complex and a 1mol / L 12mL methylaluminoxane solution. Ethylene was then continuously introduced, and the gas inlet rate was controlled to maintain the pressure inside the reactor at 5MPa and the hypergravity level at 800g. The reaction was carried out at 100℃ for 10min. After the reaction was completed, the product was separated, washed with ethanol solution, and then subjected to monomer removal, drying, and finally extrusion granulation to obtain hyperbranched polyethylene.

[0085] Comparative Example 1

[0086] The method of Example 1 was followed, except that the coordination polymerization reaction was carried out in a conventional stirred polymerization reactor, as follows:

[0087] 3L of hexane was added to a standard 5L stirred polymerization reactor, followed by a toluene solution of 0.02g of nickel diimide complex and a 1mol / L 4mL hexane solution of trichlorotriethylaluminum. Ethylene was continuously introduced, and the gas inlet rate was controlled to maintain the pressure inside the reactor at 0.8MPa. The reaction was carried out at 60℃ for 10min. After the reaction was completed, the product was separated, washed with ethanol solution, then subjected to monomer removal and drying, and finally extruded and granulated to obtain hyperbranched polyethylene.

[0088] Comparative Example 2

[0089] The method described in Example 3 was followed, except that the coordination polymerization reaction was carried out in a conventional stirred polymerization reactor. The specific method is as follows:

[0090] 3L of hexane was added to a standard 5L stirred polymerization reactor, followed by a hexane solution of 0.02g of nickel diimide complex and a 1mol / L 4mL trichlorotriethylaluminum hexane solution. Ethylene was continuously introduced, and the gas inlet rate was controlled to maintain the pressure inside the reactor at 1MPa. The reaction was carried out at 75℃ for 10min. After the reaction was completed, the product was separated, washed with ethanol solution, then subjected to monomer removal and drying, and finally extruded and granulated to obtain hyperbranched polyethylene.

[0091] Test Example 1

[0092] The molecular weight, molecular weight distribution index, melting point, melt index, and catalytic activity ratio of the hyperbranched polyethylene prepared in Examples 1-6 and Comparative Examples 1-2 are shown in Table 1.

[0093] The molecular weight of hyperbranched polyethylene was determined using high-temperature gel permeation chromatography.

[0094] The melting point of hyperbranched polyethylene was determined by differential scanning calorimetry (DSC).

[0095] Melt index determination conditions: temperature 190℃, weight of the hammer 2.16kg.

[0096] Table 1

[0097]

[0098] As shown in Table 1, through comparison of examples and comparative examples, the hyperbranched polyethylene prepared by the present invention can achieve a higher catalytic activity ratio and increase molecular weight and narrower molecular weight distribution while significantly shortening the residence time.

[0099] Test Example 2

[0100] The transparent film was prepared according to patent application CN116217431A. The transparency of the hyperbranched polyethylene film prepared in Examples 1-3 was tested using the national standard GB2410-80 "Test Method for Light Transmittance and Haze of Transparent Plastics", as shown in Table 2.

[0101] Table 2

[0102] serial number Film transparency (%) Haze (%) Example 1 91.1 3.5 Example 2 90.7 4.3 Example 3 91.5 2.9

[0103] As can be seen from the results in Table 2, the hyperbranched polyethylene film prepared by the present invention has high transparency, which is comparable to that of photovoltaic-grade polyolefin elastomers on the market (91±1%), and haze is less than 5%, making it suitable for use in photovoltaic films.

[0104] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing hyperbranched polyethylene, characterized in that, The method includes: (1) Ethylene monomer, solvent, catalyst and auxiliary catalyst are subjected to coordination polymerization reaction in a hypergravity reactor under hypergravity conditions; (2) The reaction mixture obtained in step (1) is subjected to monomer removal, washing, separation and drying; The catalyst is a nickel diimine complex; Based on the auxiliary catalyst and the metal elements contained in the catalyst, the molar ratio of the auxiliary catalyst to the catalyst is 400-1000:1; The conditions for the coordination polymerization reaction include: temperature of 60-80℃; pressure of 0.8-1.2 MPa; hypergravity level of 200-500 g; and time of 2-10 min. The auxiliary catalyst is selected from one or more of aluminoxane, alkylaluminum, and alkylaluminum chloride.

2. The method according to claim 1, characterized in that, The aluminum oxane is selected from one or more of methylaluminoxane, triisobutylaluminum-modified methylaluminoxane, ethylaluminoxane, and isobutylaluminoxane.

3. The method according to claim 1, characterized in that, The alkylaluminum is selected from one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, and tri-n-octylaluminum.

4. The method according to claim 1, characterized in that, The alkylaluminum chloride is selected from one or more of dimethylaluminum chloride, diethylaluminum chloride, ethylaluminum dichloride, and trichlorotriethylaluminum.

5. The method according to any one of claims 1-4, characterized in that, In step (1), the solvent is selected from C5-C. 12 Aliphatic alkanes and / or aromatic compounds.

6. The method according to claim 5, characterized in that, The C5-C 12 Aliphatic alkanes are selected from one or more of pentane, hexane, heptane, octane, and cyclohexane.

7. The method according to claim 5, characterized in that, The aromatic compound is toluene.

8. The method according to any one of claims 1-4, characterized in that, The raw materials for coordination polymerization reactions also include comonomers.

9. The method according to claim 8, characterized in that, The comonomer is an α-olefin and / or a polar α-olefin containing heteroatoms.

10. The method according to claim 9, characterized in that, The α-olefin is selected from one or more of propylene, 1-butene, 1-hexene, 1-octene, and 1-dodecene.

11. The method according to claim 9, characterized in that, The polar α-olefin containing heteroatoms is selected from one or more of 10-undecenoic acid, 10-undecenool, 6-chlorohexene, methyl acrylate, ethyl acrylate, and propylene acetate.

12. The method according to any one of claims 1-4, characterized in that, The raw materials for coordination polymerization reactions also contain chain transfer agents.

13. The method according to claim 12, characterized in that, The chain transfer agent is hydrogen and / or triethylzinc.

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