Method for preparing elastomer polymer under supercritical condition

Abstract

The invention provides a preparation method of an elastomeric polymer, which comprises the following steps: adding an organic solvent, a monomer, a cocatalyst and a main catalyst into a reactor under anhydrous and anaerobic conditions, and reacting under the conditions that the reaction temperature is higher than the supercritical temperature of a polymerization system and the reaction pressure is higher than the supercritical pressure of the polymerization system to obtain the elastomeric polymer. Feeding the materials into a reactor for polymerization reaction to obtain an elastomeric polymer; the monomer is one or more of alpha-olefin and ethylene of a straight chain or a branched chain with 3-20 carbon atoms. Compared with the prior art, the preparation method provided by the invention has the advantages that specific raw materials are selected and matched with specific reaction condition limitation, so that relatively good overall interaction can be realized, the problems that a solution polymerization solvent is difficult to separate, and a polymer solution is high in viscosity and relatively low in concentration are solved, and meanwhile, a supercritical polymerization process can be realized at relatively low temperature and pressure. And finally, the production cost of the supercritical process is reduced, and the load is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and more particularly, to a method for preparing an elastomeric polymer. Background Art

[0002] Elastomeric polymers are a class of polymer materials with high elasticity and reversible deformation ability, and are widely used in rubber products, sealing materials, shock-absorbing materials, medical materials and other fields. At present, the industrial production of elastomeric polymers includes gas phase method, slurry method and solution method (Prog. Polym. Sci. 2001, 26, 1287-1336.). Compared with the former two methods, solution polymerization has the advantages of small polymerization reactor volume, short polymerization time, convenient product grade switching, high ethylene single-pass conversion rate, precise control of product molecular weight, uniform copolymer composition distribution, etc. (Synthetic Resin and Plastics. 2010, 27(2), 64-68.). Therefore, solution polymerization process is widely used in the production of elastomeric polymers, including ethylene / α-olefin copolymers, ethylene-propylene rubber (EPR, EPDM), propylene-based elastomers, vinyl elastomers, etc. However, solution polymerization also has some disadvantages. For example, olefin solution polymerization uses a large amount of organic solvents, and the energy consumption and cost of solvent separation and recovery are high. In addition, in the solution polymerization process, as the polymer concentration increases, the solution viscosity increases, the mass transfer and heat transfer resistance increase, and it is easy to cause fouling in the kettle and even pipeline blockage. Therefore, the polymer concentration in solution polymerization is generally low.

[0003] The supercritical polymerization process can significantly reduce the viscosity of the traditional solution polymerization system by utilizing the unique physical properties of supercritical fluids, break through the bottleneck of mass transfer and heat dissipation at high concentrations, and is conducive to the progress of the polymerization reaction, thereby improving production capacity and load. At the same time, this process can also facilitate the separation of the polymer from the solvent, reduce the energy consumption of solvent separation and recovery, and effectively reduce production costs.

[0004] However, at the same time, the high-pressure equipment required to maintain the supercritical state in the supercritical polymerization process is costly, and the initial investment and maintenance costs of the reactor and supporting systems (such as compressors, high-pressure sealing devices) increase significantly. The supercritical process poses more stringent challenges to catalysts and requires a catalyst system with higher temperature and pressure resistance. Summary of the Invention

[0005] In view of this, the object of the present invention is to provide a method for preparing an elastomeric polymer, which can overcome the disadvantages of difficult solvent separation, large polymer solution viscosity and low concentration in solution polymerization. At the same time, the supercritical system constructed in the presence of hexane and monomers can achieve supercritical polymerization at a lower supercritical polymerization temperature and pressure, reduce the production cost of the supercritical process, and increase the load.

[0006] The present invention provides a method for preparing an elastomeric polymer, comprising the following steps:

[0007] Under anhydrous and anaerobic conditions, an organic solvent, a monomer, a cocatalyst, and a main catalyst are added into a reactor. Under the conditions that the reaction temperature is higher than the supercritical temperature of the polymerization system and the reaction pressure is higher than the supercritical pressure of the polymerization system, the materials enter the reactor for polymerization reaction to obtain an elastomeric polymer;

[0008] The monomer is one or more of linear or branched α-olefins with 3 to 20 carbon atoms and ethylene.

[0009] Preferably, the organic solvent is a C6 alkane.

[0010] Preferably, the monomer is selected from one or more of ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-hexadecene, 1-octadecene, and 1-eicosene;

[0011] The monomer is dehydrated and deoxygenated before use.

[0012] Preferably, the cocatalyst is selected from one or more of methylaluminoxane compounds, modified methylaluminoxane compounds, tris(pentafluorophenyl)boron compounds, triphenylcarbenium tetrakis(pentafluorophenyl)borate compounds, N,N-dimethylaniline tetrakis(pentafluorophenyl)borate compounds, triisobutylaluminum, and trimethylaluminum.

[0013] Preferably, the main catalyst is selected from one or more of diphenylmethylene-bis(cyclopentadienyl)zirconium dichloride, diphenylmethylene-bis(cyclopentadienyl)-(2-dimethylamino-fluorenyl)zirconium dichloride, bis[2-(3',5'-di-tert-butylphenyl)indenyl]zirconium dichloride, dicyclopentadienyl-bis(phenoxy)zirconium, vinyl-bis(indenyl)-bis(phenoxy)zirconium, bis(salicylidene-phenylimine)titanium dichloride, [N-(3,5-di-tert-butylsalicylidene)-2-diphenylphosphinobenzylidene]titanium trichloride, dimethylsilylene-bis(indenyl)zirconium dichloride, dimethylsilylene-tetramethylcyclopentadienyl-tert-butylamino-dimethyltitanium, dimethylsilylene-3-pyrrolylindenyl-tert-butylamino-dimethyltitanium, pentamethylcyclopentadienyl-(2-phenylphenoxy)-titanium dichloride, and pentamethylcyclopentadienyl-(2,6-diisopropylphenoxy)-titanium dichloride.

[0014] Preferably, the reaction temperature is 135°C to 220°C.

[0015] Preferably, the reaction pressure is 2 MPa to 10 MPa.

[0016] Preferably, the polymerization reaction is carried out in a batch polymerization, semi-continuous polymerization, or continuous polymerization manner.

[0017] Preferably, the polymerization reaction time is 2 min to 120 min.

[0018] Preferably, the weight-average molecular weight of the elastomeric polymer is 3,000 g / mol to 1,200,000 g / mol, the molecular weight distribution index is 1.0 to 5.0, and the density is 0.84 g / cm 3 ~0.93 g / cm 3 .

[0019] The present invention provides a method for preparing an elastomeric polymer, comprising the following steps: under anhydrous and anaerobic conditions, adding an organic solvent, a monomer, a cocatalyst, and a main catalyst into a reactor, and under the conditions that the reaction temperature is higher than the supercritical temperature of the polymerization system and the reaction pressure is higher than the supercritical pressure of the polymerization system, the materials enter the reactor for polymerization reaction to obtain an elastomeric polymer; the monomer is one or more of linear or branched α-olefins having 3 to 20 carbon atoms and ethylene. Compared with the prior art, the preparation method provided by the present invention selects specific raw materials in combination with specific reaction conditions, can achieve better overall interaction, thus solving the problems of difficult separation of solution polymerization solvents, high viscosity of polymer solutions, and low concentration, thereby promoting the polymerization reaction, improving production capacity and load. At the same time, it can effectively reduce the temperature and pressure of the supercritical polymerization solvent system, reduce the production cost of the supercritical process, and increase the load. Detailed embodiments

[0020] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. 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 creative efforts shall fall within the protection scope of the present invention.

[0021] The present invention provides a method for preparing an elastomeric polymer, comprising the following steps:

[0022] Under anhydrous and anaerobic conditions, adding an organic solvent, a monomer, a cocatalyst, and a main catalyst into a reactor, and under the conditions that the reaction temperature is higher than the supercritical temperature of the polymerization system and the reaction pressure is higher than the supercritical pressure of the polymerization system, the materials enter the reactor for polymerization reaction to obtain an elastomeric polymer;

[0023] The monomer is one or more of linear or branched α-olefins having 3 to 20 carbon atoms and ethylene.

[0024] In the present invention, the anhydrous and anaerobic conditions are set by using technical means well-known to those skilled in the art. For example, the reaction kettle can be achieved by flushing and replacing with a solvent and filling the kettle with a normal-pressure solvent; in addition, all the materials used are treated for water and oxygen removal.

[0025] In the present invention, the organic solvent is preferably a C6 alkane, more preferably n-hexane, isohexane or cyclohexane, and even more preferably n-hexane. There is no special limitation on the source of the organic solvent in the present invention, and commercially available products well-known to those skilled in the art can be used.

[0026] In the present invention, the monomer is one or more of linear or branched α-olefins having 3 to 20 carbon atoms and ethylene, preferably selected from one or more of ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-hexadecene, 1-octadecene, 1-eicosene, and more preferably ethylene and 1-butene. There is no special limitation on the source of the monomer in the present invention, and commercially available products well-known to those skilled in the art can be used. The monomer is subjected to water and oxygen removal before use.

[0027] In the present invention, the cocatalyst is preferably selected from one or more of methylaluminoxane compounds, modified methylaluminoxane compounds, tris(pentafluorophenyl)boron compounds, triphenylcarbenium tetrakis(pentafluorophenyl)borate compounds, N,N-dimethylaniline tetrakis(pentafluorophenyl)borate compounds, triisobutylaluminum, trimethylaluminum, and more preferably methylaluminoxane. There is no special limitation on the source of the cocatalyst in the present invention, and commercially available products well-known to those skilled in the art can be used.

[0028] In the present invention, the main catalyst is preferably selected from one or more of diphenylmethylene-bridged-cyclopentadienyl-fluorenyl zirconium dichloride, diphenylmethylene-bridged-cyclopentadienyl-(2-dimethylamino-fluorenyl) zirconium dichloride, bis[2-(3',5'-di-tert-butylphenyl)-indenyl] zirconium dichloride, dicyclopentadienyl-bis(phenoxy)zirconium, vinyl-bis(indenyl)-bis(phenoxy)zirconium, bis(salicylidene-phenylimino)titanium dichloride, [N-(3,5-di-tert-butylsalicylidene)-2-diphenylphosphinophenylimino] titanium trichloride, dimethylsilylene-bis(indenyl) zirconium dichloride, dimethylsilylene-tetramethylcyclopentadienyl-tert-butylamino-dimethyltitanium, dimethylsilylene-3-pyrrolylindenyl-tert-butylamino-dimethyltitanium, pentamethylcyclopentadienyl-(2-phenylphenoxy)-zirconium dichloride, pentamethylcyclopentadienyl-(2,6-diisopropylphenoxy)-zirconium dichloride, and more preferably diphenylmethylene-bridged-cyclopentadienyl-(2-dimethylamino-fluorenyl) zirconium dichloride. There is no special limitation on the source of the main catalyst in the present invention, and commercially available products of the above-mentioned metallocene catalysts or non-metallocene catalysts well-known to those skilled in the art can be used.

[0029] In the present invention, the dosages of the above raw materials are preferably set according to the specific reaction; in the preferred embodiments of the present invention, the concentration of the main catalyst is preferably 1 μmol / L to 50 μmol / L, more preferably 10 μmol / L to 20 μmol / L; the molar concentration ratio of the cocatalyst to the main catalyst is preferably (60 - 120):1, more preferably (80 - 100):1; the feed flow rate of ethylene is preferably 10 kg / h to 100 kg / h, more preferably 30 kg / h to 50 kg / h; the feed flow rate of butene is preferably 50 kg / h to 150 kg / h, more preferably 70 kg / h to 90 kg / h; the feed flow rate of n - hexane is preferably 100 kg / h to 300 kg / h, more preferably 170 kg / h to 190 kg / h.

[0030] In the present invention, under the conditions that the reaction temperature is higher than the supercritical temperature of the polymerization system and the reaction pressure is higher than the supercritical pressure of the polymerization system, the materials enter the reactor for polymerization reaction; the reaction temperature is preferably 135°C to 220°C, more preferably 183°C to 187°C; the reaction pressure is preferably 2 MPa to 10 MPa, more preferably 5 MPa to 7 MPa.

[0031] In the present invention, the reaction temperature, i.e., the polymerization temperature, must be higher than the supercritical temperature of the polymerization system, and at the same time the reaction pressure, i.e., the polymerization pressure, must also be higher than the supercritical pressure of the polymerization system, which is the key to solving the technical problems of the present invention.

[0032] In the present invention, the polymerization reaction mode is preferably batch polymerization, semi - continuous polymerization or continuous polymerization; when using batch or semi - continuous polymerization process, the organic solvent, monomer, cocatalyst, and main catalyst can be quantitatively added into the reaction kettle in sequence or simultaneously, but it is preferred to add them in sequence; when using continuous polymerization process, the organic solvent, monomer, cocatalyst, and main catalyst need to be continuously added into the reaction kettle simultaneously. On this basis, the present invention can be applicable to various polymerization reaction situations and has broad application prospects.

[0033] In the preferred embodiments of the present invention, the process of the polymerization reaction is specifically as follows:

[0034] Open the circulating refining system to refine n-hexane, ethylene, and 1-butene to ensure that the raw materials are anhydrous and oxygen-free; establish the feeding process for the mixed materials, heat the mixed materials to 130°C - 150°C before entering the reaction kettle to raise the temperature of the reaction kettle, and control the reaction pressure to meet the above requirements; establish the feeding processes for the main and co-catalysts, add the main and co-catalysts, and start the screw extruder to extrude and pelletize the polymer; after an obvious temperature rise, gradually lower the temperature of the mixed materials to room temperature until the reaction is stable; stabilize the reaction temperature to the above requirements, and the materials enter the reactor for polymerization reaction to obtain the polymer product.

[0035] In the present invention, the polymerization reaction time is preferably 2 min to 120 min.

[0036] The present invention provides a method for preparing an elastomeric polymer by polymerization under supercritical conditions. The prepared elastomeric polymer includes, but is not limited to, ethylene-α-olefin copolymer, propylene-based elastomer, and vinyl elastomer.

[0037] In the present invention, the weight-average molecular weight of the elastomeric polymer is preferably 3000 g / mol to 1200000 g / mol, more preferably 100000 g / mol to 250000 g / mol, the molecular weight distribution index is preferably 1.0 to 5.0, more preferably 2.0 to 3.0, and the density is preferably 0.84 g / cm 3 ~0.93 g / cm 3 ,more preferably 0.85 g / cm 3 ~0.90 g / cm 3 。

[0038] The present invention provides a method for preparing an elastomeric polymer. Under anhydrous and oxygen-free conditions, a 6C alkane solvent, a monomer, a co-catalyst, and a main catalyst are added to the reactor. The reaction temperature and pressure are set higher than the supercritical temperature and supercritical pressure of the 6C alkane solvent. The feeding concentration of the monomer is 0.1 - 20 mol / L, and the residence time of all materials in the reactor is controlled within 2 - 120 min. The monomer polymerizes in the supercritical fluid under the catalytic action of the main catalyst and the co-catalyst; it more effectively reduces the viscosity of the polymerization system, significantly improves production efficiency, and facilitates the separation of the polymer from the solvent, reducing the energy consumption for solvent separation and recovery.

[0039] The present invention provides a method for preparing an elastomeric polymer, comprising the following steps: under anhydrous and anaerobic conditions, adding an organic solvent, a monomer, a cocatalyst, and a main catalyst into a reactor; under the conditions that the reaction temperature is higher than the supercritical temperature of the polymerization system and the reaction pressure is higher than the supercritical pressure of the polymerization system, the materials enter the reactor for polymerization reaction to obtain an elastomeric polymer; the monomer is one or more of linear or branched α-olefins having 3 to 20 carbon atoms and ethylene. Compared with the prior art, the preparation method provided by the present invention selects specific raw materials and specific reaction conditions, and can achieve good overall interaction, thereby solving the problems of difficult separation of the solution polymerization solvent, high viscosity of the polymer solution, and low concentration, thereby promoting the polymerization reaction and improving the yield and load. At the same time, it can effectively reduce the temperature and pressure of the supercritical polymerization solvent system and reduce the production cost of the supercritical process.

[0040] To further illustrate the present invention, the following examples are provided for detailed description. The feed molar concentration used in the present invention refers to the initial concentration of the monomer when it enters the reactor based on the volume of the alkane solvent, and the feed molar ratio refers to the initial molar concentration ratio of the monomer to the comonomer when they enter the reaction kettle. All raw materials used in the following examples of the present invention are commercially available.

[0041] Example 1

[0042] In this experiment, the main catalyst is diphenylcarbon bridge-based-cyclopentadienyl-(2-dimethylamino-fluorenyl) zirconium dichloride, the cocatalyst is methylaluminoxane, the organic solvent is n-hexane, and the comonomer is 1-butene. Among them, 1-butene needs to be liquefied and stored under pressure at normal temperature to 4 atmospheres, and the main catalyst is used as a solution prepared with 5 ml of toluene. Before the experiment, the reaction kettle is first rinsed and replaced with a solvent, and the kettle is filled with the solvent at normal pressure.

[0043] The experimental steps are as follows: Open the circulating refining system to refine n-hexane, ethylene, and 1-butene to ensure that the raw materials are anhydrous and anaerobic. Open the feeding process of the mixed materials, heat the mixed materials to 140 °C before entering the reaction kettle to raise the temperature of the reaction kettle, and control the reaction pressure at 6 MPa. Open the feeding process of the main and cocatalysts, add the main and cocatalysts, and start the screw extruder to extrude and pelletize the polymer. After an obvious temperature rise, gradually reduce the temperature of the mixed materials until it reaches normal temperature until the reaction is stable. Stabilize the reaction temperature at 180 °C, and the residence time of the polymerization reaction is 20 min to obtain a polymer product.

[0044] In this experiment, the concentration of the main catalyst in the kettle is 15 μmol / L, the molar concentration ratio of the cocatalyst to the main catalyst is 91:1, ethylene is 41 kg / h, butene is 81 kg / h, n-hexane is 178 kg / h, and the feeding mass ratio of 1-butene to ethylene is 1.97:1. All materials used in this experiment have been treated for water and oxygen removal.

[0045] The molecular weights (Mw and Mn) of the polymer and its distribution index (PDI) were determined by high-temperature gel permeation chromatography (PL-GPC220). Using 1,2,4-trichlorobenzene as the solvent, a polymer solution with a concentration of 0.1 - 0.3 wt% was prepared at 150 °C. The measurement was carried out at 150 °C using polystyrene with a narrow molecular weight distribution as the standard sample, and the solvent flow rate was 1.0 ml / min. For all PS standard samples, the parameters k = 5.91×10 -4 , a = 0.69, and for PE, the parameter k = 1.21×10 -4 , a = 0.707.

[0046] The melting point (Tm) of the copolymer was determined by Mettler DSC 3+. An 8.0 - 10.0 mg polymer sample was heated to 120 °C at a rate of 20 °C / min, held at this temperature for 5 min to eliminate the thermal history, then cooled to -100 °C at a rate of 10 °C / min, held at this temperature for 5 min, and finally heated to 120 °C at a rate of 10 °C / min. The melting point of the polymer was obtained from the second heating curve.

[0047] The density of the polymer was measured by the drainage method.

[0048] The simulation results of the saturated vapor pressure of the mixed materials at different temperatures by ASPEN are shown in Table 1.

[0049] Table 1 Corresponding relationship between simulation temperature and saturated vapor pressure

[0050] Temperature / °C Pressure / MPa Simulation Status Supercritical State 160.00 5.654 OK No 170.00 5.772 OK No 175.00 5.778 OK No 176.00 5.774 OK No 177.00 5.768 OK No 178.00 5.758 OK No 179.00 5.765 Errors Yes 180.00 4.967 Errors Yes 185.00 5.211 Errors Yes

[0051] The experimental results are listed in Table 2 below.

[0052] Table 1 shows that when the feed composition of the reactor is 41 Kg / h of ethylene, 81 Kg / h of α-olefin, and 178 Kg / h of n-hexane, the composition of the mixed material is below the critical temperature of 178 °C. By increasing the pressure, the reaction system can be in the fully liquid phase state. When the control parameters of the reactor are above 179 °C and 5.759 MPa, the reactor system is above the critical temperature and pressure and can be in the supercritical state.

[0053] Example 2

[0054] The experimental conditions were as follows: the reaction temperature was increased to 185 °C, and the reaction pressure was 6 MPa; other conditions were the same as in Example 1. The experimental results are shown in Table 2.

[0055] Example 3

[0056] The experimental conditions were as follows: the reaction temperature was increased to 190 °C, and the reaction pressure was 6 MPa; other conditions were the same as in Example 1. The experimental results are shown in Table 2.

[0057] Comparative Experiment 1

[0058] The experimental conditions were as follows: the reaction temperature was controlled at 150°C and the reaction pressure was 6 MPa; other conditions were the same as in Example 1. The experimental results are shown in Table 2.

[0059] Comparative Experiment 2

[0060] The experimental conditions were as follows: the reaction temperature was controlled at 160°C and the reaction pressure was 6 MPa; other conditions were the same as in Example 1. The experimental results are shown in Table 2.

[0061] Comparative Experiment 3

[0062] The experimental conditions were as follows: the reaction temperature was controlled at 170°C and the reaction pressure was 6 MPa; other conditions were the same as in Example 1. The experimental results are shown in Table 2.

[0063] Table 2 Experimental Results

[0064]

[0065] The experimental results show that, when the yields are similar, that is, when the concentrations of the copolymer products in the reaction system are similar, the stirring torques of Examples 1 - 3 are much smaller than those of Comparative Experiments 1 - 3, indicating that polymerization in this supercritical fluid can greatly reduce the viscosity of the polymerization system, and at the same time, other test data of the product are stable and meet the requirements of the finished product.

[0066] Example 4: The energy consumption calculation for the device operation reaction temperature under supercritical reaction conditions is shown in Table 3.

[0067] Comparative Example 4: The energy consumption calculation for the device operation reaction temperature under non - supercritical reaction conditions is shown in Table 3.

[0068] Table 3 Comparison of the Effects of Supercritical and Non - Supercritical Processes on the Energy Consumption and Production Capacity of the Flash Evaporation and Devolatilization Process

[0069]

[0070] As shown in Table 3, when the device operation reaction temperature is increased from non - supercritical reaction conditions (150°C, 6.0 MPa) to supercritical reaction conditions (185°C, 6.0 MPa), the energy consumption of the flash heating steam is reduced by 88%. Due to the reduction of the viscosity of the material in the supercritical state, the screw conveying capacity is improved, and the production capacity of the device is increased from 80% to 100%.

[0071] In summary, the preparation method of the elastomeric polymer provided by the present invention has the following beneficial effects:

[0072] The polymerization temperature and pressure adopted in the present invention are controlled above the supercritical temperature and pressure of the polymerization system, and the polymerization is carried out in a supercritical fluid. This not only greatly reduces the viscosity of the system, is conducive to increasing the polymer concentration in the solution, and improves production efficiency; at the same time, the solid-liquid separation after the polymerization in the supercritical fluid is simple, greatly reducing the energy consumption for solvent separation and recovery; most importantly, by introducing a hexane solvent system, a supercritical system in the presence of hexane is constructed, realizing supercritical polymerization at lower temperatures and pressures, reducing the production cost of supercritical polymerization, and making it easier to achieve industrialization.

[0073] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing an elastomeric polymer, characterized in that, Comprising the following steps: Under anhydrous and anaerobic conditions, an organic solvent, a monomer, a co-catalyst, and a main catalyst are added into a reactor. Under the conditions that the reaction temperature is higher than the supercritical temperature of the system and the reaction pressure is higher than the supercritical pressure of the system, the materials enter the reactor for polymerization reaction to obtain an elastomeric polymer; The monomer is one or more of linear or branched α-olefins with 3 to 20 carbon atoms and ethylene.

2. The preparation method according to claim 1, characterized in that, The organic solvent is a C6 alkane.

3. The preparation method according to claim 1, wherein The monomer is selected from one or more of ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-hexadecene, 1-octadecene, 1-eicosene; The monomer is dehydrated and deoxygenated before use.

4. The preparation method according to claim 1, wherein, The co-catalyst is selected from one or more of methylaluminoxane compounds, modified methylaluminoxane compounds, tris(pentafluorophenyl)boron compounds, triphenylcarbenium tetrakis(pentafluorophenyl)borate compounds, N,N-dimethylaniline tetrakis(pentafluorophenyl)borate compounds, triisobutylaluminum, trimethylaluminum.

5. The preparation method according to claim 1, wherein The main catalyst is selected from one or more of diphenylmethylene-bis(cyclopentadienyl)hafnium dichloride, diphenylmethylene-bis(cyclopentadienyl)(2-dimethylamino-fluorenyl)hafnium dichloride, bis[2-(3',5'-di-tert-butylphenyl)indenyl]hafnium dichloride, dicyclopentadienyl-zirconium bis(phenoxide), vinyl-bis(indenyl)-zirconium bis(phenoxide), bis(salicylidene-phenylimino)titanium dichloride, [N-(3,5-di-tert-butylsalicylidene)-2-diphenylphosphinophenylimino]titanium trichloride, dimethylsilylene-bis(indenyl)hafnium dichloride, dimethylsilylene-tetramethylcyclopentadienyl-tert-butylamino-dimethyltitanium, dimethylsilylene-3-pyrrolylindenyl-tert-butylamino-dimethyltitanium, pentamethylcyclopentadienyl-(2-phenylphenoxide)-titanium dichloride, pentamethylcyclopentadienyl-(2,6-diisopropylphenoxide)-titanium dichloride.

6. The preparation method according to claim 1, characterized in that, The reaction temperature is 135°C to 220°C.

7. The preparation method according to claim 1, characterized in that, The reaction pressure is 2 MPa to 10 MPa.

8. The preparation method according to claim 1, characterized in that, The polymerization reaction mode is batch polymerization, semi-continuous polymerization or continuous polymerization.

9. The preparation method according to claim 1, wherein The polymerization reaction time is 2 min to 120 min.

10. The preparation method according to claim 1, characterized in that, The weight-average molecular weight of the elastomeric polymer is from 3000 g / mol to 1200000 g / mol, the molecular weight distribution index is from 1.0 to 5.0, and the density is from 0.84 g / cm 3 to 0.93 g / cm 3 .

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