Method for preparing polyolefin elastomer by adopting half-kettle process and production system

Abstract

The invention provides a method for preparing a polyolefin elastomer by adopting a half-kettle process and a production system. An organic solvent, an alpha-olefin comonomer, a cocatalyst, a main catalyst and ethylene are added into a stirred tank reactor under anhydrous and anaerobic conditions, a certain liquid level is kept in the reactor, a gas phase outlet is formed in the top of the reactor, and a gas phase and a liquid phase can be circulated. A half-kettle process is adopted, reaction heat is taken away through gas-liquid phase circulation in the reaction kettle, the temperature of the reaction kettle is controlled by adjusting the circulation amount, and energy consumption is reduced; meanwhile, due to the fact that the gas-liquid phase circulation amount is large and the solid content in the kettle is high, the production efficiency is improved, the energy consumption of devolatilization in the next step is reduced, and the defects of high energy consumption and low yield of a full-kettle process are overcome.

Description

Technical Field

[0001] The invention belongs to the technical field of polyolefin elastomer preparation, and relates to a method and a production system for preparing a polyolefin elastomer, and in particular to a method and a production system for preparing a polyolefin elastomer by adopting a semi-aqueous process. Background Art

[0002] Polyolefin elastomer (POE) is a random copolymer of ethylene / linear α-olefin with a high comonomer content developed by Dow and ExxonMobil in the early 1990s. The industrial production of ethylene / α-olefin copolymers includes gas phase method, slurry method and solution method. Compared with the first two methods, the solution method has the advantages of small polymerization reactor volume, short polymerization time, convenient product brand switching, high ethylene single-pass conversion rate, precise product molecular weight control, and uniform copolymer composition distribution. Therefore, the solution polymerization process is widely used in the production of vinyl polymers, including ethylene / α-olefin copolymers, ethylene-propylene rubber (EPR, EPDM), ethylene / styrene copolymers, ethylene / vinyl acetate copolymers (EVA), etc. Polyolefin elastomer materials have excellent weather resistance, anti-PID effect, and are not easy to yellow. It is an emerging type of photovoltaic encapsulation material.

[0003] However, solution polymerization also has some disadvantages. For example, olefin solution polymerization uses a large amount of organic solvents, and the separation and recovery of solvents consumes a lot of energy and is costly. In order to neutralize the reaction heat of the reactor, low-temperature feed is required, which consumes a lot of energy.

[0004] Therefore, how to find a more suitable production process for thermoplastic polyolefin elastomers, solve the problems existing in the above-mentioned existing processes, and make it more suitable for industrialization and practical applications has become one of the problems that many front-line researchers in the industry need to solve. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a method and a production system for preparing polyolefin elastomers, in particular, a method for preparing polyolefin elastomers using a half-kettle process. The production method provided by the present invention adopts a half-kettle polymerization process, and removes the reaction heat through gas-liquid phase circulation to reduce energy consumption; at the same time, due to the large gas-liquid phase circulation volume, the solid content in the kettle is high, and the conversion rate is improved.

[0006] The present invention provides a method for preparing a polyolefin elastomer, comprising the following steps:

[0007] 1) adding an organic solvent, an α-olefin comonomer and ethylene into a reactor, controlling the liquid level and the pressure of ethylene in the reactor, and heating the reactor;

[0008] 2) After the temperature is raised, the gas phase is discharged from the top of the reactor, separated after condensation, the separated gas phase is pressurized and returned to the raw material ethylene feed pipeline, and the separated liquid phase is pressurized and enters the liquid raw material pipeline for circulation;

[0009] 3) Adding the co-catalyst and the main catalyst into a reactor for polymerization reaction, flashing the product after the polymerization reaction, and then heating and devolatilizing the obtained liquid phase, extruding and granulating to obtain a polyolefin elastomer.

[0010] Preferably, the adding of raw materials in step 1) is specifically adding an organic solvent, an α-olefin comonomer and ethylene in an ethylene atmosphere free of water and oxygen;

[0011] The liquid level in the reactor is 20-80%;

[0012] The preparation is specifically carried out by adopting a half-kettle process;

[0013] The method is specifically a preparation method of continuous polymerization.

[0014] Preferably, the pressure of the ethylene is 3 to 5 MPa;

[0015] The feed molar ratio of the α-olefin comonomer to ethylene is (0.1-10):1;

[0016] The α-olefin comonomer is a straight-chain or branched α-olefin having 3 to 20 carbon atoms.

[0017] Preferably, the organic solvent is one or more of a linear alkane organic solvent, an isoalkane organic solvent, a cycloalkane organic solvent and an aromatic alkane organic solvent having 6 to 10 carbon atoms;

[0018] The temperature after heating is 120-150°C;

[0019] The separation temperature is 20-40°C;

[0020] The cycle time is 0.5 to 5 hours.

[0021] Preferably, the molar ratio of the co-catalyst to the main catalyst is (1.5-10000):1;

[0022] The co-catalyst used is one or more of triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, diethylaluminum chloride, ethylaluminum dichloride, methylaluminoxane, modified methylaluminoxane, perfluorophenylboron, triphenylcarbon tetrakis(pentafluorophenyl)boron salt, N,N-dimethylaniline tetrakis(pentafluorophenyl)boron salt and N,N-di(hexadecyl)aniline tetrakis(pentafluorophenyl)boron salt;

[0023] The main catalyst is a catalyst with a restricted geometry structure with a single active center.

[0024] Preferably, the polymerization reaction temperature is 120-150°C;

[0025] The polymerization reaction pressure is 3-5 MPa;

[0026] In the polymerization reaction, the residence time of the material in the reactor is 2 to 120 minutes;

[0027] During the polymerization reaction, the temperature of the reactor is controlled by adjusting the circulation amount of the gas phase and / or the liquid phase;

[0028] During the polymerization reaction, the solid content in the reaction kettle is 3% to 30%.

[0029] The present invention provides a production system for preparing a polyolefin elastomer, comprising:

[0030] Raw material refining unit, gas phase feeding unit, catalyst configuration unit, raw material pretreatment unit, polymerization reaction unit and post-treatment unit.

[0031] Preferably, the raw material refining unit comprises a storage tank for the solvent, a storage tank for the α-olefin, a diaphragm pump and a refining column;

[0032] The refining column includes one or more of a dehydration tower, a deoxygenation tower, a carbon monoxide removal tower and a decarbonylation tower;

[0033] The gas phase feeding unit includes gas storage cylinders, pressure reducing valves and refining columns for ethylene and hydrogen;

[0034] The catalyst preparation unit comprises one or more of a glove box, a storage tank and an electronic advection pump used for a catalyst, an additive, an antioxidant, and a fire extinguishing agent.

[0035] Preferably, the raw material pretreatment unit comprises a mixing kettle and flow meters for each raw material;

[0036] The polymerization reaction unit comprises a reaction kettle, a kettle top cooler, a gas-liquid separation tank, an ethylene compressor and a liquid phase pump;

[0037] The reactor top is provided with a gas phase outlet.

[0038] Preferably, the gas phase outlet of the reactor is connected to the cooler and the gas-liquid separation tank in sequence;

[0039] The gas phase outlet of the gas-liquid separation tank is connected to the ethylene compressor and the ethylene feed pipeline in sequence;

[0040] The liquid phase outlet of the gas-liquid separation tank is connected to the liquid phase pump and the liquid phase feed pipeline in sequence;

[0041] The post-processing unit comprises a flash kettle, a condenser, a heater and a gear pump.

[0042] The present invention provides a method for preparing a polyolefin elastomer, comprising the following steps: first, adding an organic solvent, an α-olefin comonomer and ethylene into a reactor, controlling the liquid level and the pressure of ethylene in the reactor, and heating the reactor; then, after heating, the gas phase is discharged from the top of the reactor, separated after condensation, the separated gas phase is pressurized and returned to the raw material ethylene feed pipeline, and the separated liquid phase is pressurized and enters the liquid raw material pipeline for circulation; finally, adding a cocatalyst and a main catalyst into the reactor for polymerization reaction, flashing the product after the polymerization reaction, and then heating the liquid phase for devolatilization, extrusion and granulation to obtain a polyolefin elastomer. Compared with the prior art, the method for preparing a polyolefin elastomer provided by the present invention is a method for preparing ethylene / α-olefin copolymers using a semi-aqueous process. The method adopts the method of adding an organic solvent, an α-olefin comonomer, a cocatalyst, a main catalyst and ethylene into a stirred tank reactor under anhydrous and oxygen-free conditions, maintaining a certain liquid level in the reactor, and having a gas phase outlet at the top of the reactor for circulation of gas and liquid phases. The present invention adopts a half-kettle process, and the reaction heat is taken away by gas-liquid phase circulation in the reactor, and the temperature of the reactor is controlled by adjusting the circulation amount, thereby reducing energy consumption; at the same time, since the gas-liquid phase circulation amount is large, the solid content in the reactor is high, the production efficiency is improved, and the energy consumption of the next step of devolatilization is reduced.

[0043] The method for preparing polyolefin elastomer by continuous polymerization through half-kettle process provided by the invention overcomes the shortcomings of high energy consumption and low yield of full-kettle process. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 The present invention provides a schematic diagram of the process flow of a polyolefin elastomer production system. DETAILED DESCRIPTION

[0045] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0046] All raw materials of the present invention have no particular limitation on their sources, and can be purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0047] The raw materials used in the present invention have no particular limitation on their purity. The present invention preferably uses industrial purity or purity conventional in the field of polyolefin elastomer preparation.

[0048] All noun expressions and abbreviations in the present invention are conventional noun expressions and abbreviations in the field. Each noun expression and abbreviation is clear and unambiguous in its relevant application field. Those skilled in the art can clearly, accurately and uniquely understand them based on the noun expressions and abbreviations.

[0049] The present invention provides a method for preparing a polyolefin elastomer, comprising the following steps:

[0050] 1) adding an organic solvent, an α-olefin comonomer and ethylene into a reactor, controlling the liquid level and the pressure of ethylene in the reactor, and heating the reactor;

[0051] 2) After the temperature is raised, the gas phase is discharged from the top of the reactor, separated after condensation, the separated gas phase is pressurized and returned to the raw material ethylene feed pipeline, and the separated liquid phase is pressurized and enters the liquid raw material pipeline for circulation;

[0052] 3) Adding the co-catalyst and the main catalyst into a reactor for polymerization reaction, flashing the product after the polymerization reaction, and then heating and devolatilizing the obtained liquid phase, extruding and granulating to obtain a polyolefin elastomer.

[0053] The present invention firstly adds an organic solvent, an alpha-olefin comonomer and ethylene into a reactor, controls the liquid level in the reactor and the pressure of ethylene, and heats the reactor.

[0054] In the present invention, the raw materials are preferably added in step 1) by adding the organic solvent, the α-olefin comonomer and ethylene in an ethylene atmosphere free of water and oxygen.

[0055] In the present invention, the liquid level in the reaction kettle is preferably 20-80%, more preferably 30-70%, and more preferably 40-60%.

[0056] In the present invention, the preparation is preferably carried out by using a half-kettle process.

[0057] In the present invention, the method is preferably a preparation method of continuous polymerization.

[0058] In the present invention, the pressure of ethylene is preferably 3 to 5 MPa, more preferably 3.4 to 4.6 MPa, and more preferably 3.8 to 4.2 MPa.

[0059] In the present invention, the feed molar ratio of the α-olefin comonomer to ethylene is preferably (0.1-10):1, more preferably (1-8):1, and more preferably (3-6):1.

[0060] In the present invention, the α-olefin comonomer is preferably a linear or branched α-olefin having 3 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, and even more preferably 11 to 12 carbon atoms.

[0061] In the present invention, the organic solvent is preferably one or more of a straight-chain alkane organic solvent, an isoalkane organic solvent, a cycloalkane organic solvent and an aromatic alkane organic solvent having 6 to 10 carbon atoms, more preferably a straight-chain alkane organic solvent, an isoalkane organic solvent, a cycloalkane organic solvent or an aromatic alkane organic solvent having 7 to 9 carbon atoms.

[0062] After the temperature is raised again, the gas phase is discharged from the top of the reactor, separated after condensation, the separated gas phase is pressurized and returned to the raw material ethylene feed pipeline, and the separated liquid phase is pressurized and enters the liquid raw material pipeline for circulation.

[0063] In the present invention, the temperature after heating is preferably 120-150°C, more preferably 125-145°C, more preferably 130-140°C, and specifically may be 140°C.

[0064] In the present invention, the separation temperature is preferably 20-40°C, more preferably 24-36°C, more preferably 28-32°C, and specifically 30°C.

[0065] In the present invention, the cycle time is preferably 0.5 to 5 hours, more preferably 1.5 to 4 hours, more preferably 2.5 to 3 hours, and specifically may be 2 hours.

[0066] Finally, the co-catalyst and the main catalyst are added into the reaction kettle to carry out polymerization reaction. The product after the polymerization reaction is flashed, and the obtained liquid phase is heated and devolatilized, extruded and granulated to obtain the polyolefin elastomer.

[0067] In the present invention, the molar ratio of the co-catalyst to the main catalyst is preferably (1.5-10000):1, more preferably (10-5000):1, and more preferably (100-1000):1.

[0068] In the present invention, the co-catalyst used is preferably one or more of triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, diethylaluminum chloride, ethylaluminum dichloride, methylaluminoxane, modified methylaluminoxane, perfluorophenyl boron, triphenylcarbon tetrakis(pentafluorophenyl)borate, N,N-dimethylaniline tetrakis(pentafluorophenyl)borate and N,N-dihexadecylaniline tetrakis(pentafluorophenyl)borate, more preferably triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, diethylaluminum chloride, ethylaluminum dichloride, methylaluminoxane, modified methylaluminoxane, perfluorophenyl boron, triphenylcarbon tetrakis(pentafluorophenyl)borate, N,N-dimethylaniline tetrakis(pentafluorophenyl)borate or N,N-dihexadecylaniline tetrakis(pentafluorophenyl)borate.

[0069] In the present invention, the main catalyst is preferably a catalyst with a constrained geometry structure of a single active center.

[0070] In the present invention, the polymerization reaction temperature is preferably 120 to 150°C, more preferably 125 to 145°C, and more preferably 130 to 140°C.

[0071] In the present invention, the polymerization reaction pressure is preferably 3 to 5 MPa, more preferably 3.4 to 4.6 MPa, and more preferably 3.8 to 4.2 MPa.

[0072] In the present invention, in the polymerization reaction, the residence time of the materials in the reactor is preferably 2 to 120 min, more preferably 20 to 100 min, and more preferably 40 to 80 min.

[0073] In the present invention, during the polymerization reaction, the temperature of the reactor is preferably controlled by adjusting the circulation amount of the gas phase and / or liquid phase, and more preferably by adjusting the circulation amount of the gas phase or liquid phase.

[0074] In the present invention, during the polymerization reaction, the solid content in the reactor is preferably 3% to 30%, more preferably 8% to 25%, and more preferably 13% to 20%.

[0075] The present invention provides a production system for preparing a polyolefin elastomer, comprising:

[0076] Raw material refining unit, gas phase feeding unit, catalyst configuration unit, raw material pretreatment unit, polymerization reaction unit and post-treatment unit.

[0077] In the present invention, the raw material refining unit preferably includes a storage tank for the solvent, a storage tank for the α-olefin, a diaphragm pump, and a refining column.

[0078] In the present invention, the refining column preferably includes one or more of a dehydration tower, a deoxygenation tower, a carbon monoxide removal tower and a decarbonylation tower, and more preferably a dehydration tower, a deoxygenation tower, a carbon monoxide removal tower or a decarbonylation tower.

[0079] In the present invention, the gas phase feeding unit preferably includes gas storage cylinders for ethylene and hydrogen, a pressure reducing valve and a refining column.

[0080] In the present invention, the catalyst preparation unit preferably includes one or more of a glove box, a storage tank and an electronic flow pump used for catalysts, additives, antioxidants and fire extinguishing agents, and more preferably a glove box, a storage tank or an electronic flow pump used for catalysts, additives, antioxidants and fire extinguishing agents.

[0081] In the present invention, the raw material pretreatment unit preferably includes a mixing kettle and flow meters for each raw material.

[0082] In the present invention, the polymerization reaction unit preferably comprises a reaction kettle, a kettle top cooler, a gas-liquid separation tank, an ethylene compressor and a liquid phase pump.

[0083] In the present invention, the top of the reactor is preferably provided with a gas phase outlet.

[0084] In the present invention, the gas phase outlet of the reactor is preferably connected to the cooler and the gas-liquid separation tank in sequence.

[0085] In the present invention, the gas phase outlet of the gas-liquid separation tank is preferably connected to the ethylene compressor and the ethylene feed pipeline in sequence.

[0086] In the present invention, the liquid phase outlet of the gas-liquid separation tank is preferably connected to the liquid phase pump and the liquid phase feed pipeline in sequence.

[0087] In the present invention, the post-treatment unit preferably includes a flash kettle, a condenser, a heater and a gear pump.

[0088] The present invention is to complete and refine the overall technical solution, better ensure the stability of polyolefin elastomer preparation and the performance of polyolefin elastomer products, and further reduce the energy consumption in the preparation process of polyolefin elastomer. The method and production system for preparing polyolefin elastomer using the semi-aqueous process may specifically include the following contents:

[0089] The invention provides a method and a production system for preparing polyolefin elastomer by adopting a half-kettle process.

[0090] The present invention provides a method for preparing ethylene / α-olefin copolymers using a semi-aqueous process. The method specifically comprises:

[0091] Under anhydrous and oxygen-free conditions, organic solvent, α-olefin comonomer, co-catalyst, main catalyst and ethylene are added into a stirred tank reactor. A certain liquid level is maintained in the reactor, and there is a gas phase outlet at the top of the reactor for gas and liquid circulation.

[0092] The solution polymerization preparation method has the following characteristics:

[0093] The reaction temperature is 120-150° C., the reaction pressure is 3-5 MPa, the concentration of the main catalyst is 0.1-20 μmol / L, the molar ratio of the co-catalyst to the main catalyst is 1.5-10000:1, the feed molar ratio of the α-olefin comonomer to ethylene is 0.1-10:1, and the residence time of all materials in the reactor is controlled at 2-120 min.

[0094] Specifically, the process is a semi-kettle polymerization process, and the preparation method is a continuous polymerization process.

[0095] Specifically, the organic solvent is a straight-chain alkane, isoalkane, cycloalkane or aromatic alkane with 6 to 10 carbon atoms, preferably one or more of n-hexane, cyclohexane, methylcyclohexane, n-heptane, isoheptane, n-octane, isooctane, n-decane, isoalkane oil (Ispoar), toluene and xylene. The solvent used needs to be free of water and oxygen.

[0096] Specifically, the ethylene needs to be dehydrated and deoxygenated.

[0097] Specifically, the α-olefin comonomer is a linear or branched α-olefin with 3 to 20 carbon atoms, preferably one or more of propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-hexadecene, 1-octadecene, and 1-eicosene. The α-olefin comonomer used needs to be dehydrated and deoxygenated.

[0098] Specifically, the co-catalyst used is triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, diethylaluminum chloride, ethylaluminum dichloride, methylaluminoxane (MAO), modified methylaluminoxane (MMAO), perfluorophenylboron, triphenylcarbonium tetrakis(pentafluorophenyl)borate, N,N-dimethylaniline tetrakis(pentafluorophenyl)borate, and N,N-dihexadecylaniline tetrakis(pentafluorophenyl)borate.

[0099] Specifically, the main catalyst is a restricted geometry catalyst with a single active center, preferably a mixture of dimethylsilyl bridge group-tetramethylcyclopentadienyl-tert-butylamino-titanium dichloride, dimethylsilyl bridge group-tetramethylcyclopentadienyl-tert-butylamino-dimethyltitanium and a boron agent, the boron agent is preferably perfluorophenyl boron, triphenylcarbonium tetrakis(pentafluorophenyl)borate, N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate, N,N-di(hexadecyl)anilinium tetrakis(pentafluorophenyl)borate, and the molar ratio of methylsilyl bridge group-tetramethylcyclopentadienyl-tert-butylamino-dimethyltitanium to the boron agent is 1:(1.2-5.0).

[0100] In the present invention, α-olefin comonomer and ethylene are copolymerized under the catalytic action of a main catalyst and a co-catalyst to obtain a copolymer with a weight average molecular weight of 3000-1000000 g / mol, a molecular weight distribution index of 1.0-7.0, and a molar content of α-olefin in the copolymer of 0.1-40%.

[0101] The present invention also provides a half-kettle process continuous polymerization device, which overcomes the shortcomings of the full-kettle process with high energy consumption and low yield.

[0102] The present invention is realized by the following device: a preparation device for ethylene / α-olefin copolymer, which comprises: a raw material refining unit, a gas phase feeding unit, a catalyst configuration unit, a raw material pretreatment unit, a polymerization reaction unit, and a post-treatment unit.

[0103] The solution polymerization preparation device has the following characteristics:

[0104] Specifically, the raw material refining unit includes a solvent, a storage tank for α-olefins, a diaphragm pump, a refining column, etc. The refining column includes any one or more of a dehydration tower, a deoxygenation tower, a carbon monoxide removal tower, and a decarbonylation tower. The function of the raw material refining unit is to remove impurities such as water and oxygen in the raw material.

[0105] Specifically, the gas phase feeding unit includes gas storage cylinders, pressure reducing valves, refining columns, etc. for ethylene and hydrogen, and the refining columns include any one or more of a dehydration tower, a deoxygenation tower, a carbon monoxide removal tower, and a carbon dioxide removal tower. The function of the gas phase feeding unit is to reduce the pressure of ethylene and hydrogen to the use pressure and remove impurities therein by refining.

[0106] Specifically, the catalyst preparation unit includes a glove box, a storage tank, an electronic advection pump, etc. for catalysts, additives, antioxidants, and fire extinguishing agents. The catalyst preparation unit is used to prepare catalyst, additives, antioxidants, and fire extinguishing agent solutions, and pressurize them into the next unit through the electronic advection pump.

[0107] Specifically, the raw material pretreatment unit includes a mixing kettle and its accessories, and flow meters for each raw material. The raw material pretreatment unit is used to accurately measure the flow of solvent, α-olefin, ethylene, and additives added to the mixing kettle, and mix them evenly in the mixing kettle, while using the additives to further remove impurities.

[0108] Specifically, the polymerization reaction unit includes a 100L reactor and its accessories, a top cooler, a gas-liquid separation tank, an ethylene compressor, a liquid phase pump and other equipment. The polymerization reaction unit is used to carry out polymerization reaction. The materials mixed evenly by the mixing kettle enter the reactor, and the catalyst solution is added into the reactor to initiate the reaction. The reactor maintains a certain liquid level, and there is a gas phase outlet at the top of the kettle, and the product outlet is in the middle of the kettle. The gas phase at the top of the kettle enters the gas-liquid separation tank after passing through the cooler, and the gas phase at the top of the tank is returned to the ethylene pipeline for reuse after being pressurized by the compressor, and the liquid phase at the bottom of the tank enters the n-hexane pipeline for reuse after being pressurized by the pump.

[0109] Specifically, the post-processing unit includes a flash kettle, a condenser, a gas-liquid separation tank, a gear pump, etc. The post-processing unit is used to remove volatile components such as solvents and unreacted α-olefins in the reaction product.

[0110] See also Figure 1 , Figure 1The present invention provides a schematic diagram of the process flow of a polyolefin elastomer production system.

[0111] In order to further illustrate the present invention, a method for preparing a polyolefin elastomer and a production system provided by the present invention are described in detail below in combination with embodiments. However, it should be understood that these embodiments are implemented on the premise of the technical scheme of the present invention, and detailed implementation methods and specific operating processes are given only to further illustrate the features and advantages of the present invention, rather than to limit the claims of the present invention, and the protection scope of the present invention is not limited to the following embodiments.

[0112] The present invention has no particular limitation on the sources of the raw materials in the following examples, and the raw materials can be prepared by methods well known to those skilled in the art or purchased from the market.

[0113] Examples 1 to 5 are ethylene / α-olefin copolymerizations carried out using a semi-kettle polymerization process in a 100 L olefin continuous polymerization reactor.

[0114] The experimental steps are: open up the process of ethylene entering the reactor and use the reactor.

[0115] Example

[0116] In this experiment, the main catalyst used was dimethylsilyl bridge-tetramethylcyclopentadienyl-tert-butylamino-dimethyltitanium, the co-catalyst used was modified methylaluminoxane, the organic solvent was n-hexane, and the co-monomer was 1-butene. n-Hexane and 1-butene were refined in advance, and ethylene entered the device after refining. The main catalyst and n-hexane were used as a solution, and the co-catalyst was diluted with n-hexane. Before the experiment, the pipeline, mixing kettle, and reactor were replaced with nitrogen three times, and then the reactor was repeatedly vacuumed and replaced with nitrogen at 140°C for 6 hours, and then vacuumed and replaced with ethylene twice, and the kettle was filled with normal pressure ethylene atmosphere, and the entire pipeline and reactor were sealed and anhydrous and oxygen-free.

[0117] The experimental steps are as follows: open the ethylene into the reactor process, increase the pressure in the reactor to 4MPa, and automatically control the pressure through the regulating valve; open the n-hexane and butene processes, introduce n-hexane and butene into the reactor, and control the flow and liquid level through the flash reactor regulating valve; turn on the reactor oil bath heating, and set the temperature to 140℃; after the reactor is heated up, the material vaporizes, and the gas phase enters the separation tank from the top of the reactor through the condenser. The material temperature in the separation tank is 30℃, and the gas phase of the separation tank is pressurized by the ethylene compressor and returned to the ethylene pipeline. The liquid phase of the separation tank is pressurized by the pump and enters the liquid raw material pipeline to form a cycle; after the system has been running for 2h, the mixing of the components is relatively stable, the catalyst and auxiliary agent processes are opened, the catalyst and auxiliary agent are added to the reactor, the reaction is started, and the temperature in the reactor is controlled by adjusting the gas phase flow rate of the reactor.

[0118] The reaction product is discharged from the middle of the kettle and enters the flash kettle after passing through the regulating valve. The flash liquid phase enters the devolatilization unit and is packaged into the final product after devolatilization granulation. The flash gas phase and the devolatilization gas phase enter the separation and recovery unit, and the solvent, butene and ethylene are separated and then used continuously.

[0119] In this experiment, the main catalyst in the reactor was prepared in a ratio of 5g catalyst + 8L n-hexane, and the co-catalyst was prepared in a ratio of 500ml co-catalyst + 9.5L n-hexane. All materials used in this experiment were treated with dehydration and deoxygenation, and the reactor volume was 100L.

[0120] Comparative Example 1

[0121] The flow rate of n-hexane into the reactor is 140kg / h, the flow rate of butene is 60kg / h, the flow rate of ethylene is 50kg / h, the flow rate of catalyst is 10ml / min, and the flow rate of co-catalyst is 25g / min. At this time, the heat released by the reaction is all used to heat the reactor, and there is no need to remove heat, that is, the gas phase circulation of the reactor does not need to be put into use. The solid content in the reactor is 8.3%.

[0122] Example 2

[0123] The flow rate of n-hexane into the kettle is 112kg / h, the flow rate of butene is 48kg / h, the flow rate of ethylene is 40kg / h, the flow rate of catalyst is 12ml / min, and the flow rate of co-catalyst is 30g / min. At this time, the heat of reaction is greater than the heat required for heating the reactor (that is, if the heat is not removed, the temperature in the reactor will be higher than the reaction temperature), the gas phase flow rate out of the reactor is 50kg / h, the gas phase reflux rate of the separation tank is 10kg / h, and the liquid phase reflux rate is 40kg / h. The solid content in the kettle is 9.5%.

[0124] Example 3

[0125] The flow rate of n-hexane into the kettle is 84kg / h, the flow rate of butene is 36kg / h, the flow rate of ethylene is 30kg / h, the flow rate of catalyst is 14ml / min, and the flow rate of co-catalyst is 35g / min. At this time, the heat of reaction is greater than the heat required for heating the reactor (that is, if the heat is not removed, the temperature in the reactor will be higher than the reaction temperature), the gas phase flow rate out of the reactor is 100kg / h, the gas phase reflux rate of the separation tank is 20kg / h, and the liquid phase reflux rate is 80kg / h. The solid content in the kettle is 11.4%.

[0126] Example 4

[0127] The flow rate of n-hexane into the kettle is 56kg / h, the flow rate of butene is 24kg / h, the flow rate of ethylene is 20kg / h, the flow rate of catalyst is 16ml / min, and the flow rate of co-catalyst is 40g / min. At this time, the heat of reaction is greater than the heat required for heating the reactor (that is, if the heat is not removed, the temperature in the reactor will be higher than the reaction temperature), the gas phase flow rate out of the reactor is 150kg / h, the gas phase reflux rate of the separation tank is 30kg / h, and the liquid phase reflux rate is 120kg / h. The solid content in the kettle is 13.5%.

[0128] Example 5

[0129] The flow rate of n-hexane into the kettle is 28kg / h, the flow rate of butene is 12kg / h, the flow rate of ethylene is 10kg / h, the flow rate of catalyst is 16ml / min, and the flow rate of co-catalyst is 40g / min. At this time, the heat of reaction is greater than the heat required for heating the reactor (that is, if the heat is not removed, the temperature in the reactor will be higher than the reaction temperature), the gas phase flow rate out of the reactor is 200kg / h, the gas phase reflux rate of the separation tank is 40kg / h, and the liquid phase reflux rate is 160kg / h. The solid content in the kettle is 15.7%.

[0130] Comparative Example 6

[0131] The full kettle reaction process was adopted, with n-hexane 185kg / h, 1-butene 67kg / h, and ethylene 48kg / h. The solid content in the kettle was 6.97%. In order to neutralize the reaction heat in the kettle, the feed temperature needed to be reduced to -20°C.

[0132] The experimental results are listed in Table 1. Table 1 is the specific data in the embodiment of the present invention.

[0133] Table 1

[0134]

[0135] It can be seen from Examples 2 to 6 that the reaction heat can be neutralized by gas phase circulation in the reactor, and low temperature feeding can reduce energy consumption compared to the full reactor process.

[0136] It can be seen from Table 1 that as the amount of catalyst increases, the reaction exotherm increases, the gas phase circulation volume of the reactor increases, and at the same time, the amount of material entering the device is reduced to keep the amount entering the reactor unchanged, and the solid content in the reactor gradually increases.

[0137] The above is a detailed introduction to a method and production system for preparing polyolefin elastomers using a semi-aqueous process provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and its core ideas of the present invention, including the best mode, and also enables any technician in the field to practice the present invention, including the manufacture and use of any device or system, and the implementation of any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, the present invention can also be improved and modified in a number of ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements that are not different from the textual expression of the claims, or if they include equivalent structural elements that are not substantially different from the textual expression of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. A method for preparing a polyolefin elastomer, characterized in that: The following steps are involved: 1) adding an organic solvent, an α-olefin comonomer and ethylene into a reactor, controlling the liquid level and the pressure of ethylene in the reactor, and heating the reactor; 2) After the temperature is raised, the gas phase is discharged from the top of the reactor, separated after condensation, the separated gas phase is pressurized and returned to the raw material ethylene feed pipeline, and the separated liquid phase is pressurized and enters the liquid raw material pipeline for circulation; 3) Adding the co-catalyst and the main catalyst into a reactor for polymerization reaction, flashing the product after the polymerization reaction, and then heating and devolatilizing the obtained liquid phase, extruding and granulating to obtain a polyolefin elastomer.

2. The method according to claim 1, characterized in that The step 1) of adding raw materials specifically comprises adding an organic solvent, an α-olefin comonomer and ethylene in an ethylene atmosphere free of water and oxygen; The liquid level in the reactor is 20-80%; The preparation is specifically carried out by adopting a half-kettle process; The method is specifically a preparation method of continuous polymerization.

3. The method according to claim 1, characterized in that The pressure of the ethylene is 3-5 MPa; The feed molar ratio of the α-olefin comonomer to ethylene is (0.1-10):1; The α-olefin comonomer is a straight-chain or branched α-olefin having 3 to 20 carbon atoms.

4. The method according to claim 1, characterized in that The organic solvent is one or more of a linear alkane organic solvent, an isomeric alkane organic solvent, a cycloalkane organic solvent and an aromatic alkane organic solvent having 6 to 10 carbon atoms; The temperature after heating is 120-150° C.; The separation temperature is 20-40°C; The cycle time is 0.5 to 5 hours.

5. The method according to claim 1, characterized in that The molar ratio of the co-catalyst to the main catalyst is (1.5-10000):1; The co-catalyst used is one or more of triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, diethylaluminum chloride, ethylaluminum dichloride, methylaluminoxane, modified methylaluminoxane, perfluorophenylboron, triphenylcarbon tetrakis(pentafluorophenyl)boron salt, N,N-dimethylaniline tetrakis(pentafluorophenyl)boron salt and N,N-di(hexadecyl)aniline tetrakis(pentafluorophenyl)boron salt; The main catalyst is a catalyst with a restricted geometry structure with a single active center.

6. The method according to claim 1, characterized in that The polymerization reaction temperature is 120-150°C; The polymerization reaction pressure is 3-5 MPa; In the polymerization reaction, the residence time of the material in the reactor is 2 to 120 minutes; During the polymerization reaction, the temperature of the reactor is controlled by adjusting the circulation amount of the gas phase and / or the liquid phase; During the polymerization reaction, the solid content in the reaction kettle is 3% to 30%.

7. A production system for preparing a polyolefin elastomer, characterized in that: include: Raw material refining unit, gas phase feeding unit, catalyst configuration unit, raw material pretreatment unit, polymerization reaction unit and post-treatment unit.

8. The production system according to claim 7, characterized in that: The raw material refining unit includes a storage tank for solvent, a storage tank for α-olefin, a diaphragm pump and a refining column; The refining column includes one or more of a dehydration tower, a deoxygenation tower, a carbon monoxide removal tower and a decarbonylation tower; The gas phase feeding unit includes gas storage cylinders, pressure reducing valves and refining columns for ethylene and hydrogen; The catalyst preparation unit comprises one or more of a glove box, a storage tank and an electronic advection pump used for a catalyst, an additive, an antioxidant, and a fire extinguishing agent.

9. The production system according to claim 7, characterized in that: The raw material pretreatment unit includes a mixing kettle and flow meters for each raw material; The polymerization reaction unit comprises a reaction kettle, a kettle top cooler, a gas-liquid separation tank, an ethylene compressor and a liquid phase pump; The reactor top is provided with a gas phase outlet.

10. The production system according to claim 9, characterized in that: The gas phase outlet of the reactor is connected to the cooler and the gas-liquid separation tank in sequence; The gas phase outlet of the gas-liquid separation tank is connected to the ethylene compressor and the ethylene feed pipeline in sequence; The liquid phase outlet of the gas-liquid separation tank is connected to the liquid phase pump and the liquid phase feed pipeline in sequence; The post-processing unit comprises a flash kettle, a condenser, a heater and a gear pump.

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