Polyolefin dissolving agent as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of new materials, and discloses a polyolefin dissolving agent as well as a preparation method and application thereof. The cleaning agent is composed of modified long-carbon-chain imidazole dinitrile amine salt, modified long-carbon-chain imidazole long-carbon-chain anion salt, betaine salt, imidazole acetate, imidazole long-carbon-chain anion salt, quaternary ammonium long-carbon-chain anion salt, imidazole bis (fluorosulfonyl) imide salt, imidazole hexafluorophosphate and long-carbon-chain anion and cation liquid. Under the condition of 180-210 DEG C, polyolefin (PP or PE) with the molecular weight of 50-8 million can be dissolved by adopting the polyolefin dissolving agent disclosed by the invention, and effective extrusion can be realized by adopting a twin-screw extruder after dissolution. After PP / PE powder is dissolved by adopting the polyolefin dissolving agent disclosed by the invention, sheet casting or spinning is carried out, casting sheets or PP / PE fibers are washed by using ethanol / dichloromethane / hydrocarbon / tetrachloroethylene to remove ionic liquid, and a polyolefin diaphragm or polyolefin fibers can be prepared.

Description

Technical Field

[0001] The present invention relates to the technical field of new materials, and particularly relates to a polyolefin solvent, a preparation method thereof, and an application thereof. Background Art

[0002] Existing lithium battery PP separators are made of polypropylene (PP) particles as raw materials, and are formed into sheets or thick films through co-extrusion technology. First, they are longitudinally stretched (MD), and then transversely stretched (TD). Their pores are less uniform than those of wet-process polyethylene separators. The dry-process production of PP separators has a lower porosity (30-40%), and the pore size distribution is uniform, which is suitable for scenarios with low requirements for electrolyte permeability. The wet-process production of separators, with high porosity and mechanical strength, meets the high energy density requirements of ternary lithium batteries and occupies the dominant position in the high-end market. So far, there has been no report of a suitable solvent for PP to be melted and processed by the wet method to produce PP separators. Summary of the Invention

[0003] The purpose of the present invention is to provide a polyolefin solvent, a preparation method thereof, and an application thereof, to solve the problems that the existing dry-process lithium battery PP separators have a lower porosity (30-40%) and are limited in high-end application scenarios.

[0004] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0005] The present invention provides a polyolefin solvent, comprising the following raw materials in parts by mass:

[0006] 15-25 parts of modified long-chain carbon imidazole dicyanamide salt, 15-30 parts of modified long-chain carbon imidazole long-chain anion salt, 10-25 parts of betaine salt, 5-20 parts of imidazole acetate, 5-10 parts of imidazole long-chain anion salt, 10-20 parts of quaternary ammonium long-chain anion salt, 5-20 parts of imidazole bis(fluorosulfonyl)imide salt, 10-30 parts of imidazole hexafluorophosphate, and 5-20 parts of long-chain cationic and anionic liquid.

[0007] Preferably, the modified long-chain carbon imidazole cations in the modified long-chain carbon imidazole dicyanamide salt and the modified long-chain carbon imidazole long-chain anion salt are independently prepared by reacting N-ethylimidazole with long-chain glycidyl ether.

[0008] Preferably, the long-chain glycidyl ether is one or more of octyl glycidyl ether, decyl glycidyl ether, fatty alcohol polyoxyethylene ether, nonylphenol glycidyl ether, ethylene glycol diglycidyl ether, coconut glucoside, lauryl glucoside, undecyl glycidyl ether, dodecyl glycidyl ether, tridecyl glycidyl ether, tetradecyl glycidyl ether, castor oil triglycidyl ether, fatty amine polyoxyethylene ether, octadecenoic acid polyoxyethylene ether, octadecenol polyoxyethylene ether, polypropylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, 1,4-cyclohexanedimethanol diglycidyl ether, neopentyl glycol diglycidyl ether.

[0009] Preferably, the long-chain anions in the modified long-chain imidazole long-chain anion salt, imidazole long-chain anion salt, and quaternary ammonium long-chain anion salt are independently one or more of dodecyl sulfonate, dodecylbenzenesulfonate, dodecanoate, tetradecanoate, hexadecanoate, octadecanoate, octadecenoate, hexadecenoate, 12-hydroxy, cis-9-octadecenoate, cis,cis-9,12-octadecadienoate, docos-13-enoic acid, docosahexaenoic acid.

[0010] Preferably, the quaternary ammonium cations in the quaternary ammonium long-chain anion salt are one or more of N,N-dimethylbenzylammonium, triethanolamine, diethanolamine, dimethylammonium, ammonium hydroxide.

[0011] Preferably, the imidazole cations in the imidazole acetate, imidazole long-chain anion salt, imidazole bis(fluorosulfonyl)imide salt, and imidazole hexafluorophosphate are independently one or more of N-methylimidazole, N-ethylimidazole, 1,2-dimethylimidazole, 2-phenylimidazole, 2-propylimidazole, 1-butyl-3-methylimidazole.

[0012] Preferably, the betaine salt is citric acid betaine salt and / or salicylic acid betaine salt.

[0013] Preferably, the long-chain ionic liquid is composed of a long-chain cation and a long-chain anion; the long-chain cation is N-tetradecylimidazole; the long-chain anion is a mixture of docosanoate, octadecenoate, and tetradecanoate.

[0014] The present invention also provides a preparation method of a polyolefin solvent, comprising the following steps:

[0015] Mix the modified long-chain imidazole dicyanamide salt, modified long-chain imidazole long-chain anion salt, betaine salt, imidazole acetate, imidazole long-chain anion salt, quaternary ammonium long-chain anion salt, imidazole bis(fluorosulfonyl)imide salt, imidazole hexafluorophosphate, and long-chain ionic liquid to obtain a polyolefin solvent.

[0016] The present invention also provides an application of a polyolefin solvent in dissolving polyethylene or polypropylene.

[0017] According to the above technical solutions, compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) Under the condition of 180-210 °C, the polyolefin solvent of the present invention can effectively dissolve polyolefins (PP or PE) with a molecular weight of 500,000-8 million, and can be effectively extruded by a twin-screw extruder after dissolution.

[0019] (2) After dissolving PP / PE powder with the polyolefin solvent of the present invention, casting or spinning is carried out, and the cast film or PP / PE fiber is washed with ethanol / dichloromethane / hydrocarbon / tetrachloroethylene to remove the ionic liquid, and a polyolefin separator or polyolefin fiber can be prepared.

[0020] (3) Ethanol is used to extract the ionic liquid on the separator, and after extraction, concentration and purification are carried out, the separation of water and ionic liquid is realized, and the recycling of the ionic liquid is realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art.

[0022] Figure 1 It is the heating and stirring diagram for dissolving PE in Application Example 1;

[0023] Figure 2 It is the apparent diagram after cooling for dissolving PE in Application Example 1;

[0024] Figure 3 It is the heating and stirring diagram for dissolving PE in Application Example 2;

[0025] Figure 4 It is the apparent diagram after cooling for dissolving PE in Application Example 2;

[0026] Figure 5 It is the heating and stirring diagram for dissolving PE in Application Example 3;

[0027] Figure 6 It is the apparent diagram after cooling for dissolving PE in Application Example 3;

[0028] Figure 7 It is the heating and stirring diagram for dissolving PE in Application Example 4;

[0029] Figure 8 It is the apparent diagram after cooling for dissolving PE in Application Example 4;

[0030] Figure 9 It is the heating and stirring diagram for dissolving PP in Application Example 5;

[0031] Figure 10 Apparent diagram of cooling after dissolving PP for Application Example 5;

[0032] Figure 11 Temperature-rising stirring diagram of dissolving PP for Application Example 6;

[0033] Figure 12 Apparent diagram of cooling after dissolving PP for Application Example 6. Detailed implementation manners

[0034] The present invention provides a polyolefin solvent, comprising raw materials in the following parts by mass:

[0035] 15 - 25 parts of modified long-chain carbon imidazole dicyanamide salt, 15 - 30 parts of modified long-chain carbon imidazole long-chain anion salt, 10 - 25 parts of betaine salt, 5 - 20 parts of imidazole acetate salt, 5 - 10 parts of imidazole long-chain anion salt, 10 - 20 parts of quaternary ammonium long-chain anion salt, 5 - 20 parts of imidazole bis(fluorosulfonyl)imide salt, 10 - 30 parts of imidazole hexafluorophosphate, and 5 - 20 parts of long-chain cationic and anionic liquid.

[0036] In the present invention, the modified long-chain carbon imidazole dicyanamide salt is preferably composed of a modified long-chain carbon imidazole cation and a dicyanamide anion.

[0037] In the present invention, the modified long-chain carbon imidazole long-chain anion salt is preferably composed of a modified long-chain carbon imidazole cation and a long-chain anion.

[0038] In the present invention, the betaine salt is preferably citric acid betaine salt and / or salicylic acid betaine salt, more preferably citric acid betaine salt or salicylic acid betaine salt, and still more preferably citric acid betaine salt.

[0039] In the present invention, the imidazole acetate salt is preferably composed of an imidazole cation and an acetate anion.

[0040] In the present invention, the imidazole long-chain anion salt is preferably composed of an imidazole cation and a long-chain anion.

[0041] In the present invention, the quaternary ammonium long-chain anion salt is preferably composed of a quaternary ammonium cation and a long-chain anion.

[0042] In the present invention, the imidazole bis(fluorosulfonyl)imide salt is preferably composed of an imidazole cation and a bis(fluorosulfonyl)imide anion.

[0043] In the present invention, the imidazole hexafluorophosphate is preferably composed of an imidazole cation and a hexafluorophosphate anion.

[0044] In the present invention, the long-chain carbon ionic liquid preferably consists of a long-chain carbon cation and a long-chain carbon anion; the long-chain carbon cation is preferably N-tetradecylimidazole; the long-chain carbon anion is preferably a mixture of docosanoate, octadecenoate, and tetradecanoate, and more preferably a mixture of docosanoate, octadecenoate, and tetradecanoate in a mass ratio of 2:2:3.

[0045] In the present invention, the modified long-chain carbon imidazole dicyanamide salt and the modified long-chain carbon imidazole long-chain carbon anion salt, the modified long-chain carbon imidazole cations are independently preferably prepared by reacting N-ethylimidazole with a long-chain glycidyl ether.

[0046] In the present invention, the molar ratio of N-ethylimidazole to the long-chain glycidyl ether is preferably 1:1 to 1.1, and more preferably 1:1; the reaction temperature is preferably 60 °C; the reaction time is preferably 2 to 4 h, more preferably 3 to 4 h, and still more preferably 4 h.

[0047] In the present invention, the long-chain glycidyl ether is preferably one or more of octyl glycidyl ether, decyl glycidyl ether, fatty alcohol polyoxyethylene ether, nonylphenol glycidyl ether, ethylene glycol diglycidyl ether, coconut glucoside, lauryl glucoside, undecyl glycidyl ether, dodecyl glycidyl ether, tridecyl glycidyl ether, tetradecyl glycidyl ether, castor oil triglycidyl ether, fatty amine polyoxyethylene ether, octadecenoic acid polyoxyethylene ether, octadecenol polyoxyethylene ether, polypropylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, 1,4-cyclohexanedimethanol diglycidyl ether, neopentyl glycol diglycidyl ether, and more preferably one or more of octyl glycidyl ether, decyl glycidyl ether, fatty alcohol polyoxyethylene ether, nonylphenol glycidyl ether, polypropylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, and still more preferably polyethylene glycol diglycidyl ether.

[0048] In the present invention, the long-chain carbon anions in the modified long-chain carbon imidazole long-chain carbon anion salt, imidazole long-chain carbon anion salt, and quaternary ammonium long-chain carbon anion salt are independently preferably one or more of dodecylsulfonate, dodecylbenzenesulfonate, dodecanoate, tetradecanoate, hexadecanoate, octadecanoate, octadecenoate, hexadecenoate, 12-hydroxy, cis-9-octadecenoate, cis,cis-9,12-octadecadienoate, docos-13-enoic acid, docosahexaenoic acid, and more preferably one or more of dodecylsulfonate, dodecylbenzenesulfonate, dodecanoate, tetradecanoate, hexadecanoate, octadecanoate, and still more preferably dodecylsulfonate.

[0049] In the present invention, the quaternary ammonium cation in the quaternary ammonium long carbon chain anion salt is preferably one or more of N,N-dimethylbenzylammonium, triethanolamine, diethanolamine, dimethylammonium, ammonium hydroxide, more preferably one or more of triethanolamine, diethanolamine, dimethylammonium, and even more preferably triethanolamine.

[0050] In the present invention, the imidazole cations in the imidazole acetate, imidazole long carbon chain anion salt, imidazole bis(fluorosulfonyl)imide salt, and imidazole hexafluorophosphate are independently preferably one or more of N-methylimidazole, N-ethylimidazole, 1,2-dimethylimidazole, 2-phenylimidazole, 2-propylimidazole, 1-butyl-3-methylimidazole, more preferably one or more of 1,2-dimethylimidazole, 2-phenylimidazole, 2-propylimidazole, and even more preferably 1-butyl-3-methylimidazole.

[0051] The present invention also provides a method for preparing a polyolefin solvent, comprising the following steps:

[0052] Mixing a modified long carbon chain imidazole dicyanamide salt, a modified long carbon chain imidazole long carbon chain anion salt, a betaine salt, an imidazole acetate, an imidazole long carbon chain anion salt, a quaternary ammonium long carbon chain anion salt, an imidazole bis(fluorosulfonyl)imide salt, an imidazole hexafluorophosphate, and a long carbon chain ionic liquid to obtain a polyolefin solvent.

[0053] The present invention also provides an application of the polyolefin solvent in dissolving polyethylene or polypropylene.

[0054] In the present invention, the mass ratio of the polyolefin solvent, polyethylene or polypropylene is preferably 70-90:10-30, more preferably 75-90:10-25, and even more preferably 80:20.

[0055] In the present invention, the temperature of the dissolution is preferably 190-230°C, more preferably 200-220°C, and even more preferably 210°C; the time of the dissolution is preferably 20 min.

[0056] In the present invention, the molecular weight of the polyethylene and polypropylene is independently preferably 600,000-10,000,000.

[0057] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without any creative effort shall fall within the protection scope of the present invention.

[0058] Example 1

[0059] This embodiment provides a polyolefin solvent, which comprises raw materials in the following parts by mass:

[0060] 15 parts of modified long-chain carbon imidazole dicyanamide salt, 20 parts of modified long-chain carbon imidazole dodecyl sulfonate, 10 parts of citric acid betaine salt, 10 parts of 1-butyl-3-methylimidazole acetate, 5 parts of 1-butyl-3-methylimidazole dodecyl sulfonate, 10 parts of triethanolamine dodecyl sulfonate, 10 parts of 1-butyl-3-methylimidazole bis(fluorosulfonyl)imide salt, 15 parts of 1-butyl-3-methylimidazole hexafluorophosphate, and 5 parts of long-chain carbon cationic and anionic liquid.

[0061] Among them, the cation in the modified long-chain carbon imidazole dicyanamide salt is prepared by feeding N-ethylimidazole and polyethylene glycol diglycidyl ether in a molar ratio of 1:1, heating to 60 °C, and reacting for 3 h;

[0062] The cation in the modified long-chain carbon imidazole dodecyl sulfonate is prepared by feeding N-ethylimidazole and polyethylene glycol diglycidyl ether in a molar ratio of 1:1.1, heating to 60 °C, and reacting for 4 h;

[0063] The cation of the long-chain carbon cationic and anionic liquid is N-tetradecylimidazole, and the anions are a mixture of docosanoate, octadecenoate, and myristate in a mass ratio of 2:2:3.

[0064] This embodiment also provides a preparation method of the polyolefin solvent, which includes the following steps:

[0065] Mix 15 parts of modified long-chain carbon imidazole dicyanamide salt, 15 parts of modified long-chain carbon imidazole dodecylbenzenesulfonate, 15 parts of salicylic acid betaine salt, 10 parts of 1,2-dimethylimidazole acetate, 5 parts of 1,2-dimethylimidazole dodecylbenzenesulfonate, 10 parts of diethanolamine dodecylbenzenesulfonate, 5 parts of 1,2-dimethylimidazole bis(fluorosulfonyl)imide salt, 15 parts of 1,2-dimethylimidazole hexafluorophosphate, and 10 parts of long-chain carbon cationic and anionic liquid for 2 h to obtain the polyolefin solvent.

[0066] Example 2

[0067] This embodiment provides a polyolefin solvent, which comprises raw materials in the following parts by mass:

[0068] 15 parts of modified long-chain carbon imidazole dicyanamide salt, 15 parts of modified long-chain carbon imidazole dodecylbenzenesulfonate, 15 parts of salicylic acid betaine salt, 10 parts of 1,2-dimethylimidazole acetate, 5 parts of 1,2-dimethylimidazole dodecylbenzenesulfonate, 10 parts of diethanolamine dodecylbenzenesulfonate, 5 parts of 1,2-dimethylimidazole bis(fluorosulfonyl)imide salt, 15 parts of 1,2-dimethylimidazole hexafluorophosphate, and 10 parts of long-chain carbon cationic and anionic liquid.

[0069] Among them, the cation in the modified long-chain carbon imidazole dicyanamide salt is prepared by feeding N-ethyl imidazole and octyl glycidyl ether in a molar ratio of 1:1.1, heating to 60 °C, and reacting for 3 h;

[0070] The cation in the modified long-chain carbon imidazole dodecylbenzenesulfonate is prepared by feeding N-ethyl imidazole and octyl glycidyl ether in a molar ratio of 1:1.05, heating to 60 °C, and reacting for 4 h;

[0071] The cation of the long-chain carbon ionic liquid is N-tetradecyl imidazole, and the anions are a mixture of docosanoate, octadecenoate, and myristate in a mass ratio of 2:2:3.

[0072] This example also provides a preparation method of a polyolefin solvent, including the following steps:

[0073] Mix the modified long-chain carbon imidazole dicyanamide salt, modified long-chain carbon imidazole dodecylbenzenesulfonate, salicyl betaine salt, 1,2-dimethylimidazole acetate, 1,2-dimethylimidazole dodecylbenzenesulfonate, diethanolamine dodecylbenzenesulfonate, 1,2-dimethylimidazole bis(fluorosulfonyl)imide salt, 1,2-dimethylimidazole hexafluorophosphate, and long-chain carbon ionic liquid for 2 h to obtain the polyolefin solvent.

[0074] Example 3

[0075] This example provides a polyolefin solvent, which contains the following raw materials in parts by mass:

[0076] 15 parts of modified long-chain carbon imidazole dicyanamide salt, 15 parts of modified long-chain carbon imidazole myristate, 10 parts of citric betaine salt, 5 parts of 1-butyl-3-methylimidazole acetate, 10 parts of 1-butyl-3-methylimidazole myristate, 10 parts of diethanolamine myristate, 10 parts of 1-butyl-3-methylimidazole bis(fluorosulfonyl)imide salt, 10 parts of 1-butyl-3-methylimidazole hexafluorophosphate, and 15 parts of long-chain carbon ionic liquid.

[0077] Among them, the cation in the modified long-chain carbon imidazole dicyanamide salt is prepared by feeding N-ethyl imidazole and nonylphenol glycidyl ether in a molar ratio of 1:1.05, heating to 60 °C, and reacting for 3 h;

[0078] The cation in the modified long-chain carbon imidazole myristate is prepared by feeding N-ethyl imidazole and nonylphenol glycidyl ether in a molar ratio of 1:1.1, heating to 60 °C, and reacting for 4 h;

[0079] The cation of the long-chain carbon ionic liquid is N-tetradecyl imidazole, and the anions are a mixture of docosanoate, octadecenoate, and myristate in a mass ratio of 2:2:3.

[0080] This embodiment also provides a preparation method of a polyolefin solvent, comprising the following steps:

[0081] Mix the modified long-chain carbon imidazole dicyanamide salt, modified long-chain carbon imidazole myristate, citric acid betaine salt, 1-butyl-3-methylimidazole acetate, 1-butyl-3-methylimidazole myristate, diethanolamine myristate, 1-butyl-3-methylimidazole bis(fluorosulfonyl)imide salt, 1-butyl-3-methylimidazole hexafluorophosphate, and long-chain carbon cationic and anionic ionic liquids for 2 h to obtain a polyolefin solvent.

[0082] Application Example 1

[0083] Add 70 parts by mass of the polyolefin solvent of Example 1 and 30 parts by mass of 1.5 million weight-average molecular weight PE powder to a round-bottom flask, place it in an oil bath for heating, use a mechanical stirrer to stir, raise the temperature to 210 °C and stir for 20 min. The PE powder is completely dissolved, and the temperature-raising stirring diagram is as Figure 1 shown. The apparent diagram after cooling when the PE powder is completely dissolved is as Figure 2 shown.

[0084] Application Example 2

[0085] Add 75 parts by mass of the polyolefin solvent of Example 1 and 25 parts by mass of 3 million weight-average molecular weight PE powder to a round-bottom flask, place it in an oil bath for heating, use a mechanical stirrer to stir, raise the temperature to 210 °C and stir for 20 min. The PE powder is completely dissolved, and the temperature-raising stirring diagram is as Figure 3 . The apparent diagram after cooling when the PE powder is completely dissolved is as Figure 4 shown.

[0086] Application Example 3

[0087] Add 80 parts by mass of the polyolefin solvent of Example 1 and 20 parts by mass of 6 million weight-average molecular weight PE powder to a round-bottom flask, place it in an oil bath for heating, use a mechanical stirrer to stir, raise the temperature to 210 °C and stir for 20 min. The PE powder is completely dissolved, and the temperature-raising stirring diagram is as Figure 5 . The apparent diagram after cooling when the PE powder is completely dissolved is as Figure 6 shown.

[0088] Application Example 4

[0089] Add 90 parts by mass of the polyolefin solvent of Example 1 and 10 parts by mass of 10 million weight-average molecular weight PE powder to a round-bottom flask, place it in an oil bath for heating, use a mechanical stirrer to stir, raise the temperature to 210 °C and stir for 20 min. The PE powder is completely dissolved, and the temperature-raising stirring diagram is as Figure 7 . The apparent diagram after cooling when the PE powder is completely dissolved is as Figure 8 shown.

[0090] Application Example 5

[0091] 70 parts by mass of the polyolefin solvent of Example 1 and 30 parts by mass of 1.5 million weight average molecular weight PP powder were added to a round bottom flask, placed in an oil bath and heated, and stirred using a mechanical stirrer. The temperature was raised to 210 °C and stirred for 20 min. The PP powder was completely dissolved. The temperature increase stirring diagram is as Figure 9 . The apparent diagram after cooling when the PP powder was completely dissolved is as Figure 10 shown.

[0092] Application Example 6

[0093] 75 parts by mass of the polyolefin solvent of Example 1 and 25 parts by mass of 2.6 million weight average molecular weight PP powder were added to a round bottom flask, placed in an oil bath and heated, and stirred using a mechanical stirrer. The temperature was raised to 210 °C and stirred for 20 min. The PP powder was completely dissolved. The temperature increase stirring diagram is as Figure 11 . The apparent diagram after cooling when the PP powder was completely dissolved is as Figure 12 shown.

[0094] The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A polyolefin solvent, characterized in that, The raw materials include the following parts by mass: 15 - 25 parts of modified long - chain carbon imidazole dicyandiamide salt, 15 - 30 parts of modified long - chain carbon imidazole long - chain anion salt, 10 - 25 parts of betaine salt, 5 - 20 parts of imidazole acetate, 5 - 10 parts of imidazole long - chain anion salt, 10 - 20 parts of quaternary ammonium long - chain anion salt, 5 - 20 parts of imidazole bis(fluorosulfonyl)imide salt, 10 - 30 parts of imidazole hexafluorophosphate, 5 - 20 parts of long - chain cation - anion ionic liquid.

2. The polyolefin solvent according to claim 1, wherein The modified long - chain carbon imidazole cations in the modified long - chain carbon imidazole dicyandiamide salt and the modified long - chain carbon imidazole long - chain anion salt are independently prepared by the reaction of N - ethyl imidazole and long - chain glycidyl ether.

3. The polyolefin solvent according to claim 2, characterized in that, The long - chain glycidyl ether is one or more of octyl glycidyl ether, decyl glycidyl ether, fatty alcohol polyoxyethylene ether, nonylphenol glycidyl ether, ethylene glycol diglycidyl ether, coconut glucoside, lauryl glucoside, undecyl glycidyl ether, dodecyl glycidyl ether, tridecyl glycidyl ether, tetradecyl glycidyl ether, castor oil triglycidyl ether, fatty amine polyoxyethylene ether, octadecenoic acid polyoxyethylene ether, octadecenol polyoxyethylene ether, polypropylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, 1,6 - hexanediol diglycidyl ether, 1,4 - cyclohexanedimethanol diglycidyl ether, neopentyl glycol diglycidyl ether.

4. A polyolefin solvent according to claim 1, characterized in that, The long - chain anions in the modified long - chain carbon imidazole long - chain anion salt, imidazole long - chain anion salt, and quaternary ammonium long - chain anion salt are independently one or more of dodecyl sulfonate, dodecylbenzenesulfonate, dodecanoate, tetradecanoate, hexadecanoate, octadecanoate, octadecenoate, hexadecenoate, 12 - hydroxy, cis - 9 - octadecenoate, cis,cis - 9,12 - octadecadienoate, docos - 13 - enoic acid, docosahexaenoic acid.

5. A polyolefin solvent according to claim 1 or 2, characterized in that, The quaternary ammonium cations in the quaternary ammonium long - chain anion salt are one or more of N,N - dimethylbenzylammonium, triethanolamine, diethanolamine, dimethylammonium, ammonium hydroxide.

6. The polyolefin solvent according to claim 5, characterized in that, The imidazole cations in the imidazole acetate, imidazole long - chain anion salt, imidazole bis(fluorosulfonyl)imide salt, and imidazole hexafluorophosphate are independently one or more of N - methyl imidazole, N - ethyl imidazole, 1,2 - dimethyl imidazole, 2 - phenyl imidazole, 2 - propyl imidazole, 1 - butyl - 3 - methyl imidazole.

7. A polyolefin solvent according to claim 6, characterized in that, The betaine salt is citric acid betaine salt and / or salicylic acid betaine salt.

8. A polyolefin solvent according to claim 1, characterized in that, The long - chain cation - anion ionic liquid is composed of a long - chain cation and a long - chain anion; the long - chain cation is N - tetradecyl imidazole; the long - chain anion is a mixture of docosanoate, octadecenoate, and tetradecanoate.

9. A method for preparing a polyolefin solvent according to any one of claims 1 to 8, characterized in that, It includes the following steps: Mix the modified long - chain carbon imidazole dicyandiamide salt, modified long - chain carbon imidazole long - chain anion salt, betaine salt, imidazole acetate, imidazole long - chain anion salt, quaternary ammonium long - chain anion salt, imidazole bis(fluorosulfonyl)imide salt, imidazole hexafluorophosphate, and long - chain cation - anion ionic liquid to obtain a polyolefin solvent.

10. Use of a polyolefin solvent according to any one of claims 1 to 8 in dissolving polyethylene or polypropylene.

Images