Continuous solution preparation method of vinyl polyolefin elastomer

Abstract

The present invention provides a continuous solution preparation method for vinyl polyolefin elastomer, belonging to the technical field of polyolefins. The continuous solution preparation method comprises: using ethylene as a single olefin raw material, under the action of a nickel diimide catalyst and a co-catalyst, performing a polymerization reaction in a solvent of at least one reactor to obtain a vinyl polyolefin elastomer glue solution; directly passing the vinyl polyolefin elastomer glue solution into a deashing unit for at least one of washing deashing and adsorption deashing to remove the nickel diimide catalyst and the co-catalyst to obtain a deashed vinyl polyolefin elastomer glue solution; continuously passing the deashed vinyl polyolefin elastomer glue solution into a devolatilization unit for static devolatilization to remove volatiles to obtain a devolatilized vinyl polyolefin elastomer glue solution; extruding and granulating the devolatilized vinyl polyolefin elastomer glue solution to obtain vinyl polyolefin elastomer particles.

Description

Technical Field

[0001] The invention relates to the technical field of polyolefins, in particular to a continuous solution preparation method for vinyl polyolefin elastomer. Background Art

[0002] Polyolefin elastomers have excellent mechanical properties, optical properties and high volume resistivity, and are widely used in toughening modification, photovoltaic films, wires and cables, and shoe foaming industries. Polyolefin elastomers are mostly prepared by ethylene and comonomer α-olefins under the catalytic action of metallocene catalysts. However, due to the high price of comonomer α-olefins, polyolefin elastomers have a high production cost. Summary of the invention

[0003] In view of this, in order to at least partially solve at least one of the above-mentioned technical problems, the present invention provides a continuous solution preparation method of ethylene-based polyolefin elastomer.

[0004] According to an embodiment of one aspect of the present invention, a continuous solution preparation method for vinyl polyolefin elastomer is provided, comprising: using ethylene as a single olefin raw material, and carrying out a polymerization reaction in a solvent of at least one reactor under the action of a nickel diimide catalyst and a co-catalyst to obtain a vinyl polyolefin elastomer glue solution; directly passing the vinyl polyolefin elastomer glue solution into a deashing unit for at least one of washing deashing and adsorption deashing to remove the nickel diimide catalyst and the co-catalyst to obtain a deashed vinyl polyolefin elastomer glue solution; continuously passing the deashed vinyl polyolefin elastomer glue solution into a devolatilization unit for static devolatilization to remove volatiles to obtain a devolatilized vinyl polyolefin elastomer glue solution; and extruding and granulating the devolatilized vinyl polyolefin elastomer glue solution to obtain vinyl polyolefin elastomer particles.

[0005] According to an embodiment of the present invention, the detergent used for washing deliming is an acid aqueous solution or an alkali aqueous solution, the percentage concentration of the acid aqueous solution or the alkali aqueous solution is 0.1~10%, the adsorbent used for adsorption deliming is molecular sieve, alumina or polyacrylamide, the washing temperature of washing deliming is 10~150℃, and the pressure is 0.1~1MPa; the adsorption temperature of adsorption deliming is 120~200℃, and the pressure is 2~8MPa.

[0006] According to an embodiment of the present invention, the diimine nickel catalyst has a structure as shown in formula (I), R1 is selected from Li, Na or K; each R2 is the same or different, and is independently selected from methyl, methoxy, trifluoromethyl, nitro or tert-butyl; each X is the same or different, and is independently selected from halogen.

[0007] Formula (I)

[0008] According to an embodiment of the present invention, the polymerization reaction is carried out in three reactors connected in series, and the conditions of the polymerization reaction are: reaction temperature is 60~200°C, reaction pressure is 1~10MPa, and residence time in each reactor is 5~60min.

[0009] According to an embodiment of the present invention, the co-catalyst includes one or more of triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, diethylaluminum chloride, ethylaluminum dichloride, methylaluminoxane, modified methylaluminoxane, perfluorophenylboron, triphenylcarbon tetrakis(pentafluorophenyl)borate, N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate and N,N-di(hexadecyl)anilinium tetrakis(pentafluorophenyl)borate; the solvent includes one or more of isobutane, n-pentane, isopentane, n-hexane, methylcyclopentane, n-heptane, methylcyclohexane, isooctane and toluene.

[0010] According to an embodiment of the present invention, deliming is primary deliming or secondary deliming, and each stage of deliming in the primary deliming or secondary deliming is independently washing deliming or adsorption deliming.

[0011] According to an embodiment of the present invention, the first stage of deliming in the two-stage deliming is washing deliming, and the second stage of deliming is adsorption deliming.

[0012] According to an embodiment of the present invention, the flow rate of ethylene is 1-2 kg / h, the molar concentration of the diimine nickel catalyst is 2-50 μmol / L, and the molar number of aluminum in the co-catalyst is 50-500 times the molar number of nickel in the diimine nickel catalyst.

[0013] According to an embodiment of the present invention, the static devolatilization is a two-stage devolatilization or a three-stage devolatilization; the two-stage devolatilization uses two flash tanks connected in series; the three-stage devolatilization uses three flash tanks connected in series; the pressure in each flash tank is 0.1~5MPa, the devolatilization temperature is 100~250℃, and the residence time of the container of the vinyl polyolefin elastomer glue after deashing in each flash tank is 3~30min.

[0014] According to an embodiment of the present invention, the temperature of extrusion granulation is 100-220° C., and the extrusion granulation is performed by a screw extruder, and the rotation speed of the screw extruder is 100-250 rpm.

[0015] According to an embodiment of the present invention, the performance parameters of the vinyl polyolefin elastomer particles are as follows: ash content ≤50ppm, volatile matter ≤100ppm, branching degree of 60-80, weight average molecular weight of 20-40×10 4 g / mol, polydispersity index is 2.0~4.0, melt index is 0.5~5.0, density is 0.850~0.880g / cm 3 .

[0016] According to an embodiment of the present invention, ethylene is used as a single olefin raw material, no other comonomers are added, and vinyl polyolefin elastomer particles are prepared by continuous solution polymerization under the action of a diimide nickel catalyst and a co-catalyst. In the preparation process, the use of expensive α-olefins and relatively expensive metallocene catalysts is avoided, and the preparation cost of vinyl polyolefin elastomer particles can be effectively reduced.

[0017] In addition, since the diimine nickel catalyst has high reactivity and water and oxygen resistance, its properties do not change after the polymerization reaction and can be directly removed by adsorption or washing. That is to say, the present invention does not require a purification step, and directly and continuously passes through a deashing unit (at least one of adsorption deashing or washing deashing) and a devolatilization unit, and then performs extrusion granulation, which can achieve the preparation of relatively pure vinyl polyolefin elastomer particles with low volatile matter and low ash content. Compared with the traditional polyolefin elastomer production process, the preparation process of the present invention is simple, has low production cost and low energy consumption, and the prepared product has low ash and volatile residues, stable product performance, and can be promoted industrially. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A flow chart of a continuous solution preparation method of an ethylene-based polyolefin elastomer according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0019] Below, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of embodiments of the present invention. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of concepts of the present invention.

[0020] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The term "comprising" used herein indicates the existence of features, steps, operations, but does not exclude the existence or addition of one or more other features.

[0021] In the related art, polyolefin elastomers are mostly prepared by copolymerizing ethylene and a comonomer α-olefin under the catalytic action of a metallocene catalyst. However, in the above copolymerization preparation process, the cost is relatively high due to the high prices of α-olefin and metallocene catalyst.

[0022] In the process of realizing the concept of the present invention, it is found that under the action of the diimine nickel catalyst and the co-catalyst, the ethylene monomer can be promoted to carry out a certain degree of chain growth, chain transfer and chain walking during the polymerization process, which is helpful to form a polyolefin elastomer with a cross-linked structure with a certain degree of branching. In addition, the present invention adopts a continuous solution preparation method, which makes the reaction process relatively simple and has low energy consumption.

[0023] Specifically, according to an embodiment of one aspect of the present invention, a continuous solution preparation method of ethylene-based polyolefin elastomer is provided. Figure 1 A flow chart of a continuous solution preparation method of a vinyl polyolefin elastomer according to an embodiment of the present invention is shown. Figure 1 As shown, the continuous solution preparation method includes operations S101 to S104.

[0024] In operation S101, ethylene is used as a single olefin raw material, and a polymerization reaction is carried out in a solvent of at least one reactor under the action of a nickel diimide catalyst and a co-catalyst to obtain a vinyl polyolefin elastomer gel.

[0025] According to the embodiment of the present invention, under the synergistic effect of the nickel diimide catalyst and the co-catalyst, ethylene chain walks during the polymerization process, so that the vinyl polyolefin elastomer rubber has a certain degree of branching.

[0026] In operation S102, the vinyl polyolefin elastomer glue liquid is directly introduced into a deashing unit for at least one of washing deashing and adsorption deashing to remove the diimide nickel catalyst and the co-catalyst to obtain the deashed vinyl polyolefin elastomer glue liquid.

[0027] According to an embodiment of the present invention, the vinyl polyolefin elastomer liquid is continuously passed into a deashing unit for at least one of washing deashing and adsorption deashing, forming a stable continuous flow process to remove impurities such as catalysts in the product to improve the purity of the vinyl polyolefin elastomer liquid and prevent the above-mentioned impurities from affecting the subsequent performance or subsequent processing of the vinyl polyolefin elastomer.

[0028] In operation S103, the deashed vinyl polyolefin elastomer solution is continuously introduced into a devolatilization unit for static devolatilization to remove volatile components, thereby obtaining a devolatilized vinyl polyolefin elastomer solution.

[0029] According to an embodiment of the present invention, static devolatilization is a process of removing volatile components in a material by heating. Static devolatilization is helpful to remove volatile impurities in the vinyl polyolefin elastomer glue and prepare a relatively pure vinyl polyolefin elastomer.

[0030] In operation S104, the devolatilized vinyl polyolefin elastomer colloid is extruded and granulated to obtain vinyl polyolefin elastomer particles.

[0031] According to the embodiments of the present invention, the above-mentioned particles are easier to package, store and transport than liquid or powder, and extrusion granulation helps to improve the subsequent reprocessing efficiency and processing stability.

[0032] According to the embodiments of the present invention, the nickel diimide catalyst used in the present invention has high catalytic activity and good water and oxygen resistance, and there is no need to perform a raw material purification process. Ethylene, nickel diimide catalyst and co-catalyst can be directly introduced into the reactor from their respective storage tanks, and a vinyl polyolefin elastomer glue is prepared by continuous solution, and then deashing, devolatilization and extrusion granulation are performed in sequence to prepare vinyl polyolefin elastomer particles with low volatility and low ash content and high purity. In the production process of the present invention, the use of relatively expensive α-olefins and relatively expensive metallocene catalysts is avoided, the production cost is low, the energy consumption is low, the ash content and volatile content in the obtained product particles are low, the product particles have stable performance, and can be widely adapted to industrial needs.

[0033] According to the embodiments of the present invention, under the catalytic action of the nickel diimide catalyst, ethylene coordinates and inserts with the nickel center of the nickel diimide catalyst, β-H elimination occurs during the insertion of ethylene, and the nickel center vacancy coordinates with new ethylene, thereby forming chain growth and chain transfer. More importantly, after β-H elimination occurs during the insertion of ethylene into the nickel center, it flips 180° and coordinates and inserts with the nickel center of the nickel diimide catalyst again, so that ethylene performs a certain degree of chain walking during the polymerization process, forming a cross-linked structure with a certain degree of branching, so that the obtained vinyl polyolefin elastomer particles have relatively excellent elasticity and flexibility.

[0034] According to an embodiment of the present invention, the detergent used for washing and deashing is an aqueous solution of acid or an aqueous solution of alkali, and the percentage concentration of the aqueous solution of acid or the aqueous solution of alkali is 0.1~10%, for example, it can be 0.1%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%. The aqueous solution of acid can be, for example, an acid solution prepared according to the above percentage concentration of any purchased strong acid or weak acid, such as sulfuric acid solution, hydrochloric acid solution or nitric acid solution. The aqueous solution of alkali can be, for example, an alkali solution prepared according to the above percentage concentration of any purchased strong base or weak base, such as sodium hydroxide solution or potassium hydroxide solution. The adsorbent used for adsorption deashing is molecular sieve, aluminum oxide or polyacrylamide. Using washing deashing or adsorption deashing helps to assist in removing impurities such as diimine nickel catalyst and co-catalyst incorporated in the product, reducing the ash content of the polyolefin elastomer product, thereby helping to improve the purity of the vinyl polyolefin elastomer, and improve its volume resistivity and transmittance. The washing temperature of washing deashing is 10-150°C, for example, 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C or 150°C, and the pressure is 0.1-1MPa, for example, 0.1MPa, 0.3MPa, 0.5MPa, 0.7MPa, 0.9MPa or 1MPa. The adsorption temperature of adsorption deashing is 120-200°C, for example, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C or 200°C, and the pressure is 2-8MPa, for example, 2MPa, 3MPa, 4MPa, 5MPa, 6MPa, 7MPa or 8MPa. Adjusting the conditions of washing deashing and adsorption deashing to the above ranges respectively helps to fully remove the ash in the vinyl polyolefin elastomer rubber solution.

[0035] According to an embodiment of the present invention, the diimine nickel catalyst has a structure as shown in formula (I): R1 is selected from Li, Na or K; each R2 is the same or different and is independently selected from methyl, methoxy, trifluoromethyl, nitro or tert-butyl; each X is the same or different and is independently selected from halogen.

[0036] Formula (I)

[0037] According to an embodiment of the present invention, as shown in formula (I), a large steric hindrance effect is constructed in the diimine nickel catalyst to control the spatial range of the subsequent nickel center and ethylene coordination, so that the vinyl polyolefin elastomer prepared when ethylene and the nickel center are coordinated has a certain degree of branching, so that when ethylene is polymerized, polyethylene with high crystallinity will not be formed, but a vinyl polyolefin elastomer with a cross-linked structure is formed, which has relatively excellent elasticity and flexibility. At the same time, the obtained vinyl polyolefin elastomer also has a high molecular weight and is suitable for a wider range of application scenarios.

[0038] According to an embodiment of the present invention, the polymerization reaction is carried out in three reactors connected in series, each reactor has a feed port for a solvent, a nickel diimide catalyst, a co-catalyst and ethylene, and each reactor can be fed with a nickel diimide catalyst or a co-catalyst as required. A single reactor, two reactors connected in series or three reactors connected in series can be used according to the reaction requirements. The conditions of the polymerization reaction are as follows: the reaction temperature is 60-200°C, for example, 60°C, 80°C, 100°C, 120°C, 140°C, 160°C, 180°C or 200°C, the reaction pressure is 1-10MPa, for example, 1MPa, 2MPa, 3MPa, 4MPa, 5MPa, 6MPa, 7MPa, 8MPa, 9MPa or 10MPa, the residence time of each reactor is 5-60min, and the residence time of the reactor is the ratio of the volume of the reactor to the ethylene flow rate, for example, 5min, 10min, 20min, 30min, 40min, 50min or 60min. When the conditions of the polymerization reaction are in the above range, ethylene can be better converted into vinyl polyolefin elastomer glue under the catalytic action of the diimide nickel catalyst.

[0039] Specifically, the cocatalyst includes one or more of triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, diethylaluminum chloride, ethylaluminum dichloride, methylaluminoxane, modified methylaluminoxane, perfluorophenylboron, triphenylcarbon tetrakis(pentafluorophenyl)borate, N,N-dimethylaniline tetrakis(pentafluorophenyl)borate and N,N-di(hexadecyl)aniline tetrakis(pentafluorophenyl)borate. The above cocatalyst can interact with the diimine nickel catalyst, change the electronic structure of the surface of the diimine nickel catalyst, enhance the activity of the diimine nickel catalyst, and improve the catalytic efficiency of the diimine nickel catalyst. In addition, the above cocatalyst helps to assist in regulating the branching degree and molecular weight distribution of the vinyl polyolefin elastomer, and the vinyl polyolefin elastomer with different performance requirements can be prepared by combining different cocatalysts with the diimine nickel catalyst.

[0040] The solvent includes one or more of isobutane, n-pentane, isopentane, n-hexane, methylcyclopentane, n-heptane, methylcyclohexane, isooctane and toluene, and the solvent is preferably one or more of n-hexane, methylcyclopentane and n-heptane, more preferably one or a combination of n-hexane and n-heptane. The above solvent helps to provide a medium environment for the polymerization reaction, promotes the full dispersion and contact of ethylene and diimine nickel catalyst and co-catalyst, and helps to promote the polymerization reaction.

[0041] More specifically, the source of ethylene can be, for example, purchased from outside or collected by a devolatilization unit, and can be stored in an ethylene storage tank for standby use as required. The source of the solvent can be, for example, purchased from outside or collected by a devolatilization unit, and can be stored in a solvent storage tank for standby use as required. The nickel diimide catalyst and the co-catalyst can be configured separately as required, and placed in a main catalyst storage tank and a co-catalyst storage tank for standby use as required. For example, the ethylene from the ethylene storage tank can be directly passed into the reactor as required, the main catalyst from the main catalyst storage tank can be directly passed into the reactor, and the solvent in the solvent storage tank and the co-catalyst in the co-catalyst storage tank can be mixed in a pipeline and then simultaneously enter the reactor for ethylene polymerization.

[0042] Further, the flow rate of ethylene is 1-2 kg / h, for example, 1 kg / h, 1.5 kg / h or 2 kg / h, and the molar concentration of the diimine nickel catalyst is 2-50 μmol / L, for example, 2 μmol / L, 10 μmol / L, 20 μmol / L, 30 μmol / L, 40 μmol / L or 50 μmol / L. The molar number of aluminum in the co-catalyst is 50-500 times the molar number of nickel in the diimine nickel catalyst, for example, 50 times, 100 times, 200 times, 300 times, 400 times or 500 times. When the parameters are set to the above range, it is helpful to regulate the branching degree of the vinyl polyolefin elastomer to 60-80, and to have good tensile strength and high molecular weight, so as to adapt to a wider range of application scenarios.

[0043] According to an embodiment of the present invention, deliming is primary deliming or secondary deliming, and each stage of deliming in the primary deliming or secondary deliming is independently washing deliming or adsorption deliming, preferably secondary deliming.

[0044] Preferably, the first stage of deashing in the two-stage deashing is washing deashing, and the second stage of deashing is adsorption deashing. Each deashing unit is set up with one in use and one in reserve, that is, one deashing unit is in use, and another identical deashing unit is in reserve. Setting the first stage of deashing as washing deashing and the second stage of deashing as adsorption deashing can reasonably control the cost of the equipment while obtaining a better ash removal effect.

[0045] According to an embodiment of the present invention, the devolatilization is a two-stage devolatilization or a three-stage devolatilization; the two-stage devolatilization uses two flash tanks connected in series, and after the two-stage devolatilization, the volatile content of the product remains below 100ppm; the three-stage devolatilization uses three flash tanks connected in series, and after the three-stage devolatilization, the volatile content of the product remains below 50ppm, preferably three-stage devolatilization. The pressure in each flash tank is 0.1~5MPa, for example, it can be 0.1MPa, 1MPa, 2MPa, 3MPa, 4MPa or 5MPa. The devolatilization temperature is 100~250℃, for example, it can be 100℃, 150℃, 200℃ or 250℃, and the residence time of the container of the vinyl polyolefin elastomer after deashing of each flash tank (that is, the volume of the flash tank and the flow rate ratio of the vinyl polyolefin elastomer) is 3~30min, for example, it can be 3min, 5min, 10min, 15min, 20min, 25min or 30min. The pressure, devolatilization temperature and residence time of the deashed vinyl polyolefin elastomer in each flash tank can be the same or different. Each flash tank can be equipped with a stirring device as required, and the stirring device can be, for example, a single-screw ribbon stirring device, a double-screw ribbon stirring device or an anchor stirring device. The devolatilization treatment helps to reduce the volatile content of the vinyl polyolefin elastomer and improve its volume resistivity and light transmittance.

[0046] It should be noted that a secondary devolatilization or a tertiary devolatilization can be arranged according to different requirements of the volatile matter of the vinyl polyolefin elastomer particles in the application field.

[0047] According to an embodiment of the present invention, the temperature of extrusion granulation is 100~220℃, for example, it can be 100℃, 120℃, 140℃, 160℃, 180℃, 200℃ or 220℃, and the extrusion granulation is carried out by a screw extruder. For example, a single screw extruder can be selected as needed, and the speed of the screw extruder is 100~250rpm, for example, it can be 100rpm, 120rpm, 140rpm, 160rpm, 180rpm, 200rpm, 220rpm, 240rpm or 250rpm. After the material is extruded, underwater pelletization is performed to obtain vinyl polyolefin elastomer particles, which are convenient for storage and transportation, and are conducive to subsequent processing according to different application requirements.

[0048] According to an embodiment of the present invention, the degree of branching of the prepared vinyl polyolefin elastomer is 60-80, and the high temperature nuclear magnetic resonance test is performed, the reagent is deuterated tetrachloroethane, and the value represents the number of branches in 1000 carbons. The volatile content tested according to GB / T24131.2-2017 is ≤100ppm. The ash content tested according to GB / T 9345.1-2008 is ≤50ppm. The hardness tested according to GB / T2411-2008 is 45-70Shore A. The tensile strength is ≥4MPa. The melt index is tested according to GB / T3682.1-2018, the temperature is 190°C, the load is 2.16kg, and the melt index of the vinyl polyolefin elastomer is 0.5-30. The weight average molecular weight (M w ) and polydispersity index (PDI) were tested according to SN / T 4183-2015, M w The melting point is 200,000 to 400,000, and the polydispersity index (PDI) is 2.0 to 4.0. m 50~70℃. Density is 0.850~0.880g / cm3 according to GB / T 1033.1-2008 test 3 The volume resistivity is tested according to GB / T 31838.2-2019, and the result is ≥1×10 17 Ω·cm. The light transmittance was tested according to GB / T 2410-2008, and the light transmittance was ≥92.5%.

[0049] The present invention is further described below by embodiments and related test experiments and results thereof. In the detailed description below, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present invention. However, it is obvious that one or more embodiments may also be implemented without these specific details. And, in the absence of conflict, the details in the following embodiments may be combined into other feasible embodiments at will.

[0050] It should be noted that the following specific examples are only for illustration, and the protection scope of the present invention is not limited thereto. The chemicals and raw materials used in the following examples are all commercially available or homemade by recognized processing methods.

[0051] Embodiment 1:

[0052] Continuous solution polymerization process:

[0053] The nickel diimide catalyst used is a catalyst having a structure shown in formula (I), wherein R1 is Li, R2 is methyl, and X is bromine. The nickel diimide catalyst can be prepared by conventional reactions in the art. The solvent in the solvent tank is n-heptane, and the ethylene tank is polymerization grade ethylene.

[0054] Polymerization reaction: the above nickel diimide catalyst and ethylene are separately introduced into the reactor, and triethylaluminum is mixed with n-heptane and then introduced into the reactor. The reaction process uses a single reactor operation, the polymerization temperature is controlled to be 70°C, the pressure is 3MPa, the ethylene flow is 2kg / h, the residence time in the reactor is 30min, the single reactor concentration of the nickel diimide catalyst is 2μmol / l, and the molar number of aluminum in triethylaluminum is 50 times the molar number of Ni in the nickel diimide catalyst, and a vinyl polyolefin elastomer glue is obtained.

[0055] Deashing: The vinyl polyolefin elastomer liquid coming out of the reactor is passed into the primary deashing unit and deashed by adsorption deashing. The adsorbent is 3A molecular sieve, the adsorption pressure is 4MPa, and the temperature is 180℃.

[0056] Devolatilization: The deashed vinyl polyolefin elastomer liquid enters the secondary devolatilization unit and passes through two flash tanks connected in series. The flash temperature of the two flash tanks is 180°C, the pressure in the flash tanks is 0.2MPa, and the stirring form in the flash tanks is single-ribbon stirring. The residence time of the deashed vinyl polyolefin elastomer liquid in the first and second flash tanks is 15min and 30min respectively.

[0057] Extrusion granulation: The devolatilized rubber solution is pumped to a single screw extruder for extrusion granulation. The screw speed is 100 rpm / min and the screw temperature is controlled at 180° C. to obtain vinyl polyolefin elastomer particles 1.

[0058] Embodiment 2:

[0059] The operation is similar to that of Example 1, except that R1 in the structure of the diimine nickel catalyst is Na, and vinyl polyolefin elastomer particles 2 are obtained.

[0060] Embodiment 3:

[0061] The operation is similar to that of Example 1, except that R1 in the diimine nickel catalyst structure is K, and vinyl polyolefin elastomer particles 3 are obtained.

[0062] Embodiment 4:

[0063] The operation is similar to that of Example 1, except that R2 in the diimide nickel catalyst structure is a methoxy group, and vinyl polyolefin elastomer particles 4 are obtained.

[0064] Embodiment 5:

[0065] The operation is similar to that of Example 1, except that R2 in the structure of the diimide nickel catalyst is tert-butyl, and vinyl polyolefin elastomer particles 5 are obtained.

[0066] Embodiment 6:

[0067] The operation is similar to that of Example 1, except that, based on Example 1, X in the structure of the diimide nickel catalyst is Cl, and vinyl polyolefin elastomer particles 6 are obtained.

[0068] Embodiment 7:

[0069] The operation is similar to that of Example 1, except that the concentration of the diimide nickel catalyst is 10 μmol / L, and vinyl polyolefin elastomer particles 7 are obtained.

[0070] Embodiment 8:

[0071] The operation is similar to that of Example 1, except that the concentration of the diimide nickel catalyst is 50 μmol / L, to obtain vinyl polyolefin elastomer particles 8.

[0072] Embodiment 9:

[0073] The operation is similar to that of Example 1, except that the co-catalyst for the polymerization reaction is methylaluminoxane, and vinyl polyolefin elastomer particles 9 are obtained.

[0074] Embodiment 10:

[0075] The operation is similar to that of Example 9, except that the molar number of methylaluminoxane aluminum in the polymerization reaction is 200 times the molar number of Ni in the diimine nickel catalyst, to obtain vinyl polyolefin elastomer particles 10.

[0076] Embodiment 11:

[0077] The operation is similar to that of Example 1, except that the polymerization reaction uses three reactors in series. The polymerization temperature of the three reactors is 70°C and the pressure is 3MPa. The ethylene flow rate of the first reactor is 1.5kg / h, the residence time is 15min, the single-reactor concentration of the diimine nickel catalyst is 1.5μmol / l, and the molar number of aluminum in triethylaluminum is 50 times the molar number of the diimine nickel catalyst Ni. The ethylene flow rate of the second reactor is 0.5kg / h, the residence time is 5min, the single-reactor concentration of the diimine nickel catalyst is 0.5μmol / l, and the molar number of aluminum in triethylaluminum is 50 times the molar number of the catalyst Ni. No ethylene, main catalyst and co-catalyst are added to the third reactor to obtain vinyl polyolefin elastomer particles 11.

[0078] Embodiment 12:

[0079] The operation is similar to that of Example 1, except that the adsorbent used for deashing is aluminum oxide, and vinyl polyolefin elastomer particles 12 are obtained.

[0080] Embodiment 13:

[0081] The operation is similar to that of Example 1, except that the deashing is a two-stage deashing, wherein the first stage of deashing is washing deashing, the detergent is a 0.1wt% hydrochloric acid aqueous solution, the temperature is 80°C, and the pressure is 0.1MPa. The second stage of deashing is adsorption deashing, the adsorbent is aluminum oxide, the pressure is 4MPa, and the temperature is 180°C, and vinyl polyolefin elastomer particles 13 are obtained.

[0082] Embodiment 14:

[0083] The operation is similar to that of Example 13, with the main difference being that the devolatilization is a three-stage devolatilization, i.e., it passes through three flash tanks connected in series, the flash temperature of the first two flash tanks is 180°C, the pressure in the flash tanks is 0.2 MPa, the stirring form in the flash tanks is single-ribbon stirring, the residence time of the rubber solution in the first and second flash tanks is 5 min and 10 min, respectively, the flash temperature of the last flash tank is 220°C, the pressure in the flash tank is 0.1 MPa, the stirring form in the flash tank is anchor stirring, and the residence time of the rubber solution in the third flash tank is 10 min, to obtain vinyl polyolefin elastomer particles 14.

[0084] Embodiment 15:

[0085] The aforementioned steps of this Example 15 are the same as those of Example 14, except that during extrusion granulation, the screw speed is set to 180 rpm / min and the screw temperature is adjusted to 150° C. to obtain vinyl polyolefin elastomer particles 15.

[0086] Comparative Example 1:

[0087] The polymerization reaction process is the same as that in Example 1, except that in this comparative example 1, the deashing unit is not passed through, and the vinyl polyolefin elastomer solution obtained by polymerization is directly passed through a flash tank. The flash temperature, the pressure of the flash tank, and the stirring form in the flash tank are the same as those in Example 1, and the residence time of the vinyl polyolefin elastomer solution obtained by polymerization in the flash tank is 15 minutes.

[0088] After flash evaporation, extrusion granulation was carried out in the same manner as in Example 1 to obtain vinyl polyolefin elastomer particles 1'.

[0089] The performance indicators of the vinyl polyolefin elastomer particles prepared in Examples 1 to 8 are shown in Table 1 below.

[0090] Table 1 Performance test results of vinyl polyolefin elastomers of Examples 1 to 8

[0091]

[0092] By comparing Examples 1 to 6, it can be found that although the vinyl polyolefin elastomer prepared by the nickel diimide catalysts of different structures provided by the present invention has slight differences in performance, the ash content and volatile content are both low, showing higher volume resistivity, higher mechanical strength and higher light transmittance. By comparing Example 1 with Examples 7 and 8, it can be found that with the substantial increase in the concentration of the nickel diimide catalyst, the ash content only increases by 5 to 8 ppm, and the volatile content does not increase substantially, proving that the deashing and devolatilization process of the present invention has a better effect, and can achieve continuous production of relatively pure vinyl polyolefin elastomer particles.

[0093] The performance indicators of the vinyl polyolefin elastomer particles prepared in Examples 9 to 15 are shown in Table 2 below.

[0094] Table 2 Performance test results of vinyl polyolefin elastomers of Examples 9 to 15

[0095]

[0096] By comparing Example 1 with Example 9, it can be found that triethylaluminum and methylaluminoxane have no change on polymer performance as cocatalysts, proving that under the premise of ensuring that polymer performance is basically unchanged, triethylaluminum with lower price can be used to replace expensive methylaluminoxane. By comparing Example 9 with Example 10, it can be found that even if the amount of cocatalyst is increased by 4 times, the ash and volatile matter remaining in the polymer are also basically unchanged, proving that the deashing and devolatilization technology of the present invention has a more significant effect, and can realize the continuous production of purer vinyl polyolefin elastomer. By comparing Example 1 with Example 11, it can be found that using three kettles in series operation can ensure that ash and volatile matter are basically unchanged while improving the molecular weight of the polymer, and mechanical properties, volume resistivity and light transmittance are also basically unchanged, and different forms of single kettle or double kettles in series or three kettles in series can be used according to different application requirements of the product. By comparing Example 1, Example 12, Example 13 and Example 14, it can be found that from the first-level deashing to the second-level deashing, the ash content in the vinyl polyolefin elastomer is significantly reduced, and from the second-level devolatilization to the third-level devolatilization, the volatile matter content in the vinyl polyolefin elastomer is significantly reduced. At the same time, as the ash and volatile content decrease, the volume resistivity and light transmittance of the vinyl polyolefin elastomer are significantly improved. By comparing Example 14 and Example 15, it can be seen that adjusting the conditions of extrusion granulation has a certain influence on the product performance, but the performance difference is not large, indicating that the extrusion granulation parameters of the above examples can prepare vinyl polyolefin elastomers with higher performance.

[0097] Table 3 Performance test results of polyolefin elastomers prepared in Example 1 and Comparative Example 1

[0098]

[0099] As shown in Table 3 above, it can be found from Example 1 and Comparative Example 1 that, compared with Example 1, the post-treatment process of Comparative Example 1 has only one-stage flash evaporation, and the polymer ash and volatile matter are relatively high. At the same time, the volume resistivity and transmittance are seriously reduced, which makes it difficult to promote the application.

[0100] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A continuous solution preparation method for vinyl polyolefin elastomer, characterized in that: The continuous solution preparation method comprises: Using ethylene as a single olefin raw material, a polymerization reaction is carried out in a solvent of at least one reactor under the action of a diimide nickel catalyst and a co-catalyst to obtain a vinyl polyolefin elastomer glue; Directly passing the vinyl polyolefin elastomer glue into a deashing unit for at least one of washing deashing and adsorption deashing to remove the diimide nickel catalyst and the co-catalyst to obtain a deashed vinyl polyolefin elastomer glue; The deashed vinyl polyolefin elastomer glue solution is continuously introduced into a devolatilization unit for static devolatilization to remove volatile components, thereby obtaining a devolatilized vinyl polyolefin elastomer glue solution; The devolatilized vinyl polyolefin elastomer colloid is extruded and granulated to obtain vinyl polyolefin elastomer particles.

2. The method for preparing a continuous solution according to claim 1, characterized in that: The detergent used in the washing deashing is an acid aqueous solution or an alkali aqueous solution, the percentage concentration of the acid aqueous solution or the alkali aqueous solution is 0.1-10%, and the adsorbent used in the adsorption deashing is a molecular sieve, alumina or polyacrylamide. The washing temperature of the washing and deashing is 10-150°C and the pressure is 0.1-1MPa; The adsorption temperature of the adsorption deashing is 120-200° C. and the pressure is 2-8 MPa.

3. The method for preparing a continuous solution according to claim 1, characterized in that: The nickel diimide catalyst has a structure as shown in formula (I): Formula (I); R1 is selected from Li, Na or K; Each R2 is the same or different and is independently selected from methyl, methoxy, trifluoromethyl, nitro or tert-butyl; Each X is the same or different and is independently selected from halogen.

4. The method for preparing a continuous solution according to claim 1, characterized in that: The polymerization reaction is carried out in three reactors connected in series, and the conditions of the polymerization reaction are: The reaction temperature is 60~200°C, the reaction pressure is 1~10MPa, and the residence time in each reactor is 5~60min.

5. The method for preparing a continuous solution according to claim 1, characterized in that: The cocatalyst includes one or more of triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, diethylaluminum chloride, diethylaluminum chloride, methylaluminoxane, modified methylaluminoxane, perfluorophenylboron, triphenylcarbon tetrakis(pentafluorophenyl)borate, N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate and N,N-di(hexadecyl)anilinium tetrakis(pentafluorophenyl)borate; The solvent includes one or more of isobutane, n-pentane, isopentane, n-hexane, methylcyclopentane, n-heptane, methylcyclohexane, isooctane and toluene.

6. The method for preparing a continuous solution according to claim 1 or 2, characterized in that: The deliming is primary deliming or secondary deliming, and each stage of the primary deliming or secondary deliming is independently washing deliming or adsorption deliming.

7. The method for preparing a continuous solution according to claim 5, characterized in that: The flow rate of ethylene is 1-2 kg / h, the molar concentration of the diimine nickel catalyst is 2-50 μmol / L, and the molar number of aluminum in the co-catalyst is 50-500 times the molar number of nickel in the diimine nickel catalyst.

8. The method for preparing a continuous solution according to claim 1 or 2, characterized in that: The static devolatilization is a secondary devolatilization or a tertiary devolatilization; The secondary devolatilization uses two flash tanks connected in series; The three-stage devolatilization uses three flash tanks connected in series; The pressure in each flash tank is 0.1-5 MPa, the devolatilization temperature is 100-250° C., and the residence time of the deashed vinyl polyolefin elastomer solution in each flash tank is 3-30 min.

9. The method for preparing a continuous solution according to claim 1, characterized in that: The temperature of the extrusion granulation is 100-220° C., and the extrusion granulation is performed by a screw extruder, and the rotation speed of the screw extruder is 100-250 rpm.

10. The method for preparing a continuous solution according to claim 1, characterized in that: The performance parameters of the vinyl polyolefin elastomer particles are as follows: Ash ≤50ppm, volatile matter ≤100ppm, branching degree 60~80, weight average molecular weight 20~40×10 4 g / mol, polydispersity index is 2.0~4.0, melt index is 0.5~30, density is 0.850~0.880g / cm 3 .

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