Process for producing polymers

Abstract

A method of producing a polymer, the method comprising (i) feeding a monomer stream comprising monomers for producing the polymer to a polymerization unit comprising at least one reaction vessel, at least one polymer-containing reaction mixture is produced in the polymerization unit in the presence of at least one solvent and at least one catalyst in the polymerization reaction, (ii) feeding at least a portion of the reaction mixture comprising polymer, catalyst and optionally monomer produced in the polymerization unit to a recycle line to form a recycle stream, (iii) reducing the temperature of the recycle stream, (iv) feeding the recycle stream to the polymerization unit, the monomer stream, or both after its temperature has been reduced, and wherein the polymer is an elastomer selected from the group consisting of: (a) an ethylene / alpha-olefin copolymer having at least 20% by weight of units derived from ethylene, and which may optionally further comprise units derived from at least one non-conjugated diene having 6 to 30 carbon atoms, the present invention relates to a composition comprising (a) a non-conjugated diene, preferably selected from the group consisting of dicyclopentadiene (DCPD), 5-ethylene-2-norbornene (ENB), 5-vinyl-2-norbornene (VNB), and combinations thereof, (b) a polybutadiene and (c) a butadiene copolymer having at least 50 wt% units derived from butadiene wherein preferably at least one reaction vessel of polymerization units has a reactor volume of at least 4 liters, and wherein the process preferably further comprises a step (v) comprising removing the solvent and separating the polymer from the reaction mixture produced in the polymerization unit, preferably by feeding the reaction mixture produced in the polymerization unit into at least one post-treatment section to remove the solvent and separate the polymer.

Description

Technical Field

[0001] The present disclosure relates to a method for producing a polymer using a polymerization catalyst and a solvent. Background Art

[0002] Many widely used synthetic rubbers are produced by solution or slurry polymerization using one or more polymerization catalysts. In order to optimize the mixing of catalysts and reactants, polymerization is typically carried out in a stirred tank reactor. The polymerization reaction is usually exothermic, and the catalyst is deactivated above a certain temperature threshold. Therefore, the temperature in the reactor must be controlled and kept below the temperature at which the catalyst is deactivated. Cooling the reactor by an external or internal cooling device may lead to poor reaction control and reactor fouling, as described in, for example, international patent application WO 2010040732. Continuous polymerization is typically carried out in a so-called adiabatic reactor, where the reactor temperature is mainly set by the target polymer concentration and the temperature of the monomer / solvent mixture feed stream. Typically, the monomer feed is cooled to a temperature significantly below 0°C in one or more cooler units before they enter the reaction vessel, at which time the temperature in the reactor should be maintained at a fixed predetermined value in the range of about 60°C to 120°C to allow polymerization to proceed, thereby forming a high molecular weight polymer while avoiding catalyst deactivation. However, cooling the monomer / solvent feed to a low temperature consumes energy and significantly increases production costs. In the method described in WO 2010040732, polymerization is carried out under boiling conditions in a polymerization reactor. The reactor temperature is controlled using the cooling effect of the evaporating fluid in the reactor. The vapor phase from the reactor is fed into a condenser and cooled to a low temperature in a supercooler, then combined with a new monomer / solvent feed stream and fed into the reactor again. However, operating the reactor under boiling conditions is not very economical either, because only a portion of the reactor volume can be used for polymerization. In addition, the condensation of the vapor phase also increases energy costs. In international patent application WO 2016109264, a polymerization method using at least two reactors is described, wherein at least one reactor is a loop reactor. A cooling stream containing monomers, solvents and hydrogen is fed into a first reactor, in which a reaction mixture containing a polymer is produced. The reaction mixture is fed into a loop reactor, in which new cooling monomers, solvents and hydrogen are added. A catalyst is fed into the loop reactor to carry out a second polymerization in the loop reactor. The method reportedly reduces the load on the devolatilization unit, in which the solvent is removed from the reaction mixture to separate the polymer, which reportedly saves energy costs. Therefore, energy savings are achieved during the post-processing stage after the polymerization reaction has occurred in this method. It is suggested in WO2020 / 05311A1 and WO2020 / 05337A1 to polymerize the feedstock in a loop reactor to produce a polyolefin product, thereby improving heat transfer compared to a stirred tank reactor. A loop reactor is described as being generally a number of heat exchangers in a loop. The examples provided in these documents are software simulations.

[0003] There remains a need for alternative methods for producing polymers by polymerization using at least one solvent and at least one catalyst at lower energy costs. Preferably, the method is suitable for producing polymers having a high weight average molecular weight, for example a molecular weight of at least 50 kg / mole or at least 200 kg / mole. Summary of the invention

[0004] Therefore, there is provided a method for producing a polymer, the method comprising

[0005] A method for producing a polymer, the method comprising

[0006] (i) feeding a monomer stream containing monomers for producing a polymer into a polymerization unit comprising at least one reaction vessel, in which polymerization unit at least one reaction mixture comprising a polymer is produced in a polymerization reaction in the presence of at least one solvent and at least one catalyst,

[0007] (ii) feeding at least a portion of the reaction mixture comprising polymer, catalyst and optionally monomers produced in the polymerization unit into the recycle line to form a recycle stream,

[0008] (iii) reducing the temperature of the recirculation stream,

[0009] (iv) feeding the recycle stream after its temperature has been reduced to the polymerization unit, the monomer stream or both,

[0010] and wherein the polymer is an elastomer selected from the group consisting of: (a) ethylene / α-olefin copolymers having at least 20 wt. % of units derived from ethylene and which optionally may further comprise units derived from at least one non-conjugated diene having 6 to 30 carbon atoms, preferably selected from the group consisting of dicyclopentadiene (DCPD), 5-ethylidene-2-norbornene (ENB), 5-vinyl-2-norbornene (VNB) and combinations thereof, (b) polybutadiene and (c) butadiene copolymers having at least 50 wt. % of units derived from butadiene, wherein preferably at least one reaction vessel of the polymerization unit has a reactor volume of at least 4 liters, and wherein the process preferably further comprises a step (v) comprising removing the solvent from the reaction mixture produced in the polymerization unit and isolating the polymer, preferably by feeding the reaction mixture produced in the polymerization unit to at least one post-treatment section to remove the solvent and isolate the polymer. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a schematic diagram of the general method of the present disclosure.

[0012] Figure 2 is a schematic diagram of an embodiment of the disclosed process wherein two polymerization reactors are connected in series.

[0013] Figure 3 is a schematic diagram of another embodiment of the disclosed process wherein two reactor vessels are connected in series.

[0014] Figure 4 is a schematic diagram of an embodiment of the disclosed process wherein two reactor vessels are connected in parallel. DETAILED DESCRIPTION

[0015] The method according to the present disclosure will now be described in more detail in the following description.

[0016] In the following description, the terms "comprising", "containing", "including", "having" are not intended to exclude the existence of any additional components, steps or procedures, whether or not the same components, steps or procedures are specifically disclosed. If the existence of any additional components, steps or procedures is intended to be excluded, the term "consisting of..." is used.

[0017] In the following description, the specification may be used. If not otherwise stated, the specification is used in the version valid on March 1, 2020. If there is no version valid on that date, for example because the specification has expired, reference is made to the version valid on the date closest to March 1, 2020.

[0018] In the following description, the amount of a component of a composition or polymer may be indicated by "weight percent", "wt. %" or "% by weight". The terms "weight percent", "wt. %" or "% by weight" are used interchangeably and are based on the total weight of the composition or polymer, respectively, which is 100%, unless otherwise specified.

[0019] The term "phr" means parts per hundred parts of rubber, ie the weight percent based on the total amount of rubber which is set to 100%.

[0020] Unless otherwise stated, ranges identified in this disclosure are intended to include and disclose all values ​​between and including the endpoints of the range.

[0021] polymer :

[0022] Polymers with broad or narrow molecular weight distributions (Mw / Mn) can be produced. In one embodiment, polymers with molecular weight distributions (Mw / Mn) of 1.80 to 30 or 2 to 10 can be produced.

[0023] Preferably, the polymer is an elastomer (also referred to as a rubber). Among other things, an elastomer can be identified by its Mooney viscosity - in contrast to thermoplastic polymers, which are typically identified by their melting point or melt viscosity. Polymers with high or low Mooney viscosities can be produced. In one embodiment, the polymer produced by the method has a Mooney viscosity ML 1+4 of at least 20, preferably at least 40 at 125°C and a Mooney viscosity ML 1+8 of up to 100 at 150°C. In one embodiment of the present disclosure, the polymer has a Mooney viscosity ML 1+4 of about 40 to about 100 at 125°C. In another embodiment of the present disclosure, the polymer has a Mooney viscosity ML 1+8 of about 50 to about 100 at 150°C.

[0024] Polymers with high or low weight average molecular weight (Mw) can be produced by the method according to the present disclosure, although an advantage of the present disclosure is that high molecular weight polymers can also be produced, such as polymers with a molecular weight (Mw) of at least 50.000 g / mol or even at least 200.000 g / mol. In one embodiment of the present disclosure, polymers with a molecular weight (Mw) of 50 kg / mol to 150 kg / mol are produced. In another embodiment of the present disclosure, the polymer has a Mw of at least 200,000 g / mol, such as about 200,000 g / mol to about 600,000 g / mol or about 200,000 g / mol to about 500,000 g / mol.

[0025] Polymers with high or low number average molecular weights (Mn) can be produced. In one embodiment, the polymer produced by the method according to the present disclosure has an Mn of 40,000 to 250,000 g / mol. In one embodiment of the present disclosure, the polymer produced by the method has a z-average molecular weight (Mz) of about 100 kg / mol to 3000 kg / mol, preferably about 200 kg / mol to about 2000 kg / mol.

[0026] Branched or linear polymers can be produced using the method according to the present disclosure. The branching level of branched polymers can be high, medium or low. The polymer branching level can be characterized by the parameter Δδ. Δδ (expressed in degrees) is the difference between the phase angle δ at a frequency of 0.1rad / s and the phase angle δ at a frequency of 100rad / s, as determined by dynamic mechanical spectroscopy (DMS) at 125°C and 10% strain. The amount Δδ is a measure of the amount of long-chain branched structures in the polymer, and has been introduced in HC Booij, Kautschuk+Gummi Kunststoffe [Raw Rubber, Rubber and Plastics], Vol. 44, No. 2, pp. 128-130, which is incorporated herein by reference. The lower the Δδ, the more branched structures there are in the polymer. In one embodiment of the present disclosure, a polymer with a Δδ of 2 to 50 is produced.

[0027] The polymers produced by the method according to the present disclosure can be random polymers or block copolymers. They can be unimodal, or they can be bimodal or multimodal, i.e. they can have a molecular weight distribution characterized by two peaks in the case of bimodal polymers or a molecular weight distribution characterized by more than two peaks in the case of multimodal polymers in a graph obtained by gel permeation chromatography (GPC). Reactor blends can also be produced, which means that the polymers are produced in at least two different reaction vessels and are combined by blending, typically wet blending, i.e. by blending the reaction mixtures.

[0028] It is expected that the method according to the present disclosure can be applied to any polymerization method using at least one polymerization catalyst solvent and wherein the reaction is exothermic to produce polymer. This can include producing thermoplastic or elastomeric polymers and can include producing rubber, and these rubbers include rubbers such as EPM, EPDM, IR, BR, SBR and HNBR. However, the method may be most useful for producing a rubber selected from the following: (a) ethylene / alpha-olefin copolymer, it has at least 20 weight % of units derived from ethylene, and it can optionally further include units derived from at least one non-conjugated diene with 6 to 30 carbon atoms, the non-conjugated diene is preferably selected from dicyclopentadiene (DCPD), 5-ethylidene-2-norbornene (ENB), 5-vinyl-2-norbornene (VNB) and combinations thereof, (b) polybutadiene and (c) butadiene copolymer, it has at least 20 weight % or at least 50 weight % of units derived from butadiene. In a preferred embodiment of the present disclosure, polymer includes ethylene / alpha-olefin polymer and butadiene polymer.

[0029] Ethylene / α-olefin polymers:

[0030] In one embodiment, the polymer produced by the method according to the present disclosure is an ethylene / alpha-olefin-polymer. Ethylene / alpha-olefin-polymer is a copolymer of ethylene and alpha-olefin and optionally one or more other comonomers. Can produce ethylene / alpha-olefin polymers containing at least 20 weight % (based on the gross weight of the polymer) of units derived from ethylene and can contain up to 80 weight percent (wt.%) of units derived from ethylene. In one embodiment, the ethylene-alpha-olefin-copolymer of the present disclosure comprises 40 to 70wt.%, preferably 44 to 65wt.% or 50 to 60wt.% of units derived from ethylene. The weight percent is based on the gross weight of the copolymer.

[0031] In addition to units derived from ethylene, polymers according to the present disclosure contain units derived from one or more α-olefins.

[0032] α-Olefins:

[0033] Alpha-olefins are olefins with a single aliphatic carbon-carbon double bond. The double bond is located at the end (alpha position) of the olefin. Alpha-olefins can be aromatic or aliphatic, straight chain, branched or cyclic. Typically, alpha-olefins have 3 to 20 carbon atoms.

[0034] α-olefins include those represented by the formula: H2C=X-CH3,

[0035] wherein X represents an aliphatic alkylene residue having 1 to 17 carbon atoms, which may be linear or branched. Preferably, the branches independently contain 1 to 3 carbon atoms.

[0036] In preferred embodiments, α-olefins include those represented by the formula: H2C=CH-(CH2) n -CH3, wherein n= represents 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 and 17.

[0037] Preferred examples of α-olefins include, but are not limited to, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 9-methyl-1-decene, 11-methyl-1-dodecene, and 12-ethyl-1-tetradecene.

[0038] One or more alpha-olefins can be used in combination. Preferably, the polymer contains at least 5 wt.% or at least 10 wt.% of units derived from one or more alpha-olefins. It is possible to produce polymers containing up to 57 wt.%, more preferably up to 55 wt.% of units derived from one or more alpha-olefins (weight percentage (wt.%) based on the total weight of the polymer). Preferably, the ethylene-alpha-olefin-copolymer contains 17 to 57 wt.% of total units derived from one or more alpha-olefins. Preferably, the polymer contains propylene.

[0039] Non-conjugated dienes:

[0040] Ethylene / α-olefin polymers can be produced which contain, in addition to ethylene and α-olefins, units derived from one or more non-conjugated dienes as comonomers.

[0041] Non-conjugated dienes are polyenes comprising at least two carbon-carbon double bonds, the double bonds being non-conjugated and being able to be present in a chain, a ring, a ring system or a combination thereof. The carbon-carbon double bonds are separated by at least two carbon atoms. The polyene may have endocyclic and / or exocyclic double bonds and may not have identical or different substituents. Preferably, the non-conjugated diene is aliphatic, more preferably aliphatic and alicyclic. Suitable non-conjugated dienes include, for example, aromatic polyenes, aliphatic polyenes and alicyclic polyenes, preferably polyenes (C6-C 30 -polyene, more preferably C6-C 30Specific examples of non-conjugated dienes include, but are not limited to, 1,4-hexadiene, 3-methyl-1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 4-ethyl-1,4-hexadiene, 3,3-dimethyl-1,4-hexadiene, 5-methyl-1,4-heptadiene, 5-ethyl-1,4-heptadiene, 5-methyl-1,5-heptadiene, 6-methyl-1,5-heptadiene, 5-ethyl-1,5-heptadiene, 1,6-octadiene, 4-methyl-1,4-octadiene, 5-methyl-1,4-octadiene, 4-ethyl ...5-ethyl-1,4-octadiene, 6-methyl-1,5-heptadiene, 5-ethyl-1,5-heptadiene, 1,6-octadiene, 4-methyl-1,4-octadiene, 5-methyl-1,4-octadiene, 4-ethyl-1,4-octadiene, 5-methyl-1,4-octadiene, 4-ethyl-1,4-octadiene, 5-methyl-1,4-octadiene, 5-ethyl-1,4-octadiene, 5-methyl-1,4-oc 1,6-octadiene, 6-methyl-1,5-octadiene, 6-ethyl-1,5-octadiene, 1,6-octadiene, 6-methyl-1,6-octadiene, 7-methyl-1,6-octadiene, 6-ethyl-1,6-octadiene, 6-propyl-1,6-octadiene, 6-butyl-1,6-octadiene, 4-methyl-1,4-nonadiene, 5-methyl-1,4-nonadiene, 4-ethyl-1,4-nonadiene, 5-ethyl-1,4-nonadiene, 5-methyl-1,5-nonadiene olefins, 6-methyl-1,5-nonadiene, 5-ethyl-1,5-nonadiene, 6-ethyl-1,5-nonadiene, 6-methyl-1,6-nonadiene, 7-methyl-1,6-nonadiene, 6-ethyl-1,6-nonadiene, 7-ethyl-1,6-nonadiene, 7-methyl-1,7-nonadiene, 8-methyl-1,7-nonadiene, 7-ethyl-1,7-nonadiene, 5-methyl-1,4-decadiene, 5-ethyl-1,4-decadiene, 5-methyl-1,5-decadiene, 6-methyl-1,5-decadiene, 5-ethyl-1,5-decadiene, 6-ethyl- 1,5-decadiene, 6-methyl-1,6-decadiene, 6-ethyl-1,6-decadiene, 7-methyl-1,6-decadiene, 7-ethyl-1,6-decadiene, 7-methyl-1,7-decadiene, 8-methyl-1,7-decadiene, 7-ethyl-1,7-decadiene, 8-ethyl-1,7-decadiene, 8-methyl-1,8-decadiene, 9-methyl-1,8-decadiene, 8-ethyl-1,8-decadiene, 1,5,9-decatriene, 6-methyl-1,6-undecadiene, 9-methyl-1,8-undecadiene, dicyclopentadiene, and mixtures thereof. Preferred non-conjugated dienes include alicyclic polyenes. The alicyclic diene has at least one cyclic unit. In a preferred embodiment, the non-conjugated diene is selected from a polyene having at least one endocyclic double bond and optionally at least one exocyclic double bond. Preferred examples include dicyclopentadiene, 5-methylene-2-norbornene and 5-ethylidene-2-norbornene (ENB), with ENB being particularly preferred. In one embodiment, the copolymer of the present disclosure contains only ENB as the non-conjugated diene.

[0042] Other examples of non-conjugated dienes include dipolymerizable dienes, including α-ω-dienes (preferably linear α-ω-dienes), vinyl-substituted monocyclic and bicyclic non-conjugated dienes, which may be aromatic or aliphatic. Such dipolymerizable dienes may cause or contribute to the formation of polymer branches because the two double bonds of the diene may participate in the polymerization. Examples of aliphatic dipolymerizable dienes include, but are not limited to, 1,4-divinylcyclohexane, 1,3-divinylcyclohexane, 1,3-divinylcyclopentane, 1,5-divinylcyclooctane, 1-allyl-4-vinylcyclohexane, 1,4-diallylcyclohexane, 1-allyl-5-vinylcyclooctane, 1,5-diallylcyclooctane, 1-allyl-4-isopropenyl-cyclohexane, 1-isopropenyl-4-vinylcyclohexane and 1-isopropenyl-3-vinylcyclopentane, dicyclopentadiene (DCPD) and 1,4-cyclohexadiene. Preferred are non-conjugated vinyl norbornene and C8-C 12 αω linear diene (e.g., 1,7-octadiene, 1,8-nonadiene, 1,9-decadiene, 1,10-undecadiene, 1,11-dodecadiene). The dipolymerizable diene may be further substituted with at least one group containing a heteroatom of Groups 13-17 (e.g., O, S, N, P, Cl, F, I, Br, or a combination thereof).

[0043] In a preferred embodiment of the present disclosure, the dimerizable diene is selected from dicyclopentadiene (DCPD), 5-vinyl-2-norbornene (VNB), 1,7-octadiene and 1,9-decadiene or a combination thereof, wherein 5-vinyl-2-norbornene (VNB) is most preferred.

[0044] Examples of the aromatic non-conjugated polyene include vinylbenzene (including isomers thereof) and vinyl-isopropenylbenzene (including isomers thereof).

[0045] In typical embodiments of the present disclosure, ethylene / α-olefin copolymers containing at least 3 wt. % and up to and including 15 wt. % of units derived from one or more non-conjugated dienes can be produced.

[0046] In another embodiment, a polymer containing a non-conjugated diene selected from dicyclopentadiene (DCPD), 5-ethylidene-2-norbornene (ENB), 5-vinyl-2-norbornene (VNB), 1,7-octadiene or 1,9-decadiene or a combination thereof is produced. Preferably, the copolymer of the present disclosure contains 0.05 wt.% to 5 wt.%, more preferably 0.10 wt.% to 3 wt.% or 0.15 wt.% to 1.2 wt.% of units derived from VNB (all weight percentages are based on the total weight of the ethylene-α-olefin-copolymer). In another embodiment, an ethylene / α-olefin copolymer containing units derived from 5-ethylidene-2-norbornene and 5-vinyl-2-norbornene can be produced, for example, the produced ethylene / α-olefin copolymer can contain 2 to 15 wt.% of units derived from ENB and 0.05 to 4 wt.% of units derived from VNB.

[0047] Ethylene / α-olefin copolymers can be produced by the process according to the present disclosure, which may or may not contain units derived from other comonomers. Based on the total weight of the ethylene / α-olefin polymer, the sum of units derived from ethylene, α-olefins and optional non-conjugated dienes may be greater than 90wt.%, greater than 99wt.% and include 100wt.%.

[0048] Butadiene polymer:

[0049] In one embodiment of the present disclosure, the polymer is a butadiene polymer. Butadiene polymers include homopolymers and copolymers of 1,3-butadiene. Preferably, the butadiene polymer contains at least 20%, preferably at least 50% by weight, preferably at least 60% by weight of units derived from 1,3-butadiene based on the weight of the polymer. In one embodiment of the present disclosure, the diene polymer contains at least 60% by weight or at least 75% by weight of units derived from 1,3-butadiene. Butadiene polymers can contain 0% to 49% by weight, or 0% to 40% by weight of units derived from one or more comonomers based on the total weight of the polymer.

[0050] Suitable comonomers include, but are not limited to, conjugated dienes, preferably having 5 to 24, more preferably 5 to 20 carbon atoms.

[0051] Specific examples of conjugated dienes include, but are not limited to, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 1-phenyl-1,3-butadiene, 1,3-hexadiene, myrcene, ocimene, farnesene, and combinations thereof.

[0052] Suitable comonomers also include vinyl aromatic comonomers, preferably vinyl aromatic comonomers having 8 to 30 carbon atoms. Specific examples of vinyl aromatic comonomers include, but are not limited to, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-butylstyrene, vinylnaphthalene, divinylbenzene, trivinylbenzene, divinylnaphthalene, and combinations thereof.

[0053] Suitable comonomers further include one or more α-olefins such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, and combinations thereof.

[0054] In one embodiment, the diene polymer according to the present disclosure contains 0 to 20 wt% of units derived from ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, and combinations thereof.

[0055] Suitable comonomers also include, but are not limited to, one or more other copolymerizable comonomers that introduce functional groups including crosslinking sites, branching sites, branches, or functionalized groups. In one embodiment of the present disclosure, the diene polymer contains 0 wt % to 10 wt % or 0 wt % to 5 wt % of units derived from one or more such other comonomers.

[0056] Combinations of one or more comonomers of the same chemical type as described above as well as combinations of one or more comonomers from different chemical types may be used.

[0057] Solvents :

[0058] The polymerization is preferably carried out in the presence of at least one solvent. Preferably, the polymerization is carried out as a solution polymerization. Preferred solvents include one or more inert hydrocarbon solvents. Suitable solvents include C 5-12 Hydrocarbons such as pentane, hexane, heptane, octane, cycloheptane, cyclohexane, methylcyclohexane, methylcycloheptane, pentamethylheptane, hydrogenated naphtha, isomers and mixtures thereof. In another embodiment, the polymerization is carried out as a slurry polymerization. This can typically be used when the catalyst is provided on a solid support that is insoluble under the polymerization conditions.

[0059] Chain transfer agent :

[0060] In a preferred embodiment, the polymerization includes the use of one or more chain transfer agents to control the molecular weight of the polymer. Preferred chain transfer agents include hydrogen (H2). Other chain transfer agents include, but are not limited to, ethane, diethyl zinc, and combinations thereof.

[0061] catalyst :

[0062] The polymers can be produced by using one or more than one conventional polymerization catalysts suitable for use in the polymerization of the corresponding polymer to be produced. Typical examples include Ziegler-Natta catalysts, organometallic catalysts or metallocene-type catalysts. Ziegler-Natta catalysts are polymerization catalysts based on halides of transition metals, in particular titanium or vanadium.

[0063] Organometallic catalysts, particularly those containing nickel, cobalt, titanium or rare earth metals are typically used to produce butadiene polymers. Rare earth catalysts include organometallic compounds containing neodymium, praseodymium, cerium, lanthanum, gadolinium and dysprosium or combinations thereof.

[0064] Examples of suitable catalysts are disclosed in Canadian Patent Application CA 1,143,711A, US Patent No. 4,260,707, US Patent Application No. US2013 / 0172489A1 or as described in paragraphs

[0011] to

[0049] of EP 2 819 853A1, all of which are incorporated herein by reference.

[0065] Metallocene catalysts are organometallic catalysts in which a metal (typically Ti, Hf or Zr) is bonded to at least one cyclic organic ligand, preferably at least one ligand based on cyclopentadienyl, fluorenyl or indenyl. Catalysts in which metals are bonded to two anionic aromatic ligands are typically referred to as "metallocene catalysts" in the art. Catalysts in which the second anionic aromatic ligand is replaced by another organic ligand are referred to as "semi-metallocene catalysts". Metal catalysts in which both anionic ligands are replaced by organic residues are referred to as "post-metallocene catalysts" in the art. Metallocene catalysts include metallocenes, post-metallocenes and semi-metallocene catalysts. Suitable metallocene polymerization catalysts are known in the art and are described in, for example, WO2005 / 090418A1, WO2016 / 114914A1, WO2017 / 048448, US2015 / 0025209A1, all of which are incorporated herein by reference.

[0066] Typically, one or more co-catalysts are added to the reaction vessel. Typical co-catalysts include, but are not limited to, boron-containing activators. In a preferred embodiment, the activator (b) is selected from borane (C1) or borate (C2 or C3).

[0067] Suitable boron activators (C1) can be represented by the general formula BQ1Q2Q3.

[0068] Suitable borate activators according to (C2) can be represented by the general formula G(BQ1Q2Q3Q4).

[0069] Suitable borate activators according to (C3) can be represented by the general formula (JH)(BQ1Q2Q3Q4).

[0070] In the activator according to (C1), B is boron and Q1 to Q3 are substituted or unsubstituted aryl, preferably phenyl. Suitable substituents include, but are not limited to, halogen, preferably fluoride, and C1 to C 40 Hydrocarbyl, preferably C1 to C 20 Alkyl, or aromatic compounds. Specific examples of the activator according to (C1) include tris(pentafluorophenyl)borane, tris(2,3,5,6-tetrafluorophenyl)borane, tris(2,3,4,5-tetrafluorophenyl)borane, tris(3,4,5-trifluorophenyl)borane, tris(2,3,4-trifluorophenyl)borane, phenyl-bis(pentafluorophenyl)borane, and the like.

[0071] In the activator according to (C2), G is an inorganic or organic cation, B is boron, and Q1 to Q3 are the same as in (C1), and Q4 is also a substituted or unsubstituted aryl, preferably a substituted or unsubstituted phenyl. The substituents include, but are not limited to, halogen, preferably fluoride, and C1 to C 40 Hydrocarbyl, preferably C1 to C 20 Alkyl, or aromatic compounds. Specific examples of borate groups (BQ1Q2Q3Q4) include, but are not limited to, tetrakis (pentafluorophenyl) borate, tetrakis (2,3,5,6-tetrafluorophenyl) borate, tetrakis (2,3,4,5-tetrafluorophenyl) borate, tetrakis (3,4,5-trifluorophenyl) borate, tetrakis (2,3,4-trifluorophenyl) borate, phenyl tris (pentafluorophenyl) borate, tetrakis (3,5-bis trifluoromethylphenyl) borate, etc. Specific examples of G include ferrocenium cations, alkyl-substituted ferrocenium cations, silver cations, etc. Specific examples of organic cations G include triphenylmethyl cations, etc. G is preferably a carbenium cation, and is particularly preferably a triphenylmethyl cation.

[0072] In the activator according to (C3), J represents a neutral Lewis base, (JH) represents a Bronsted acid, B is boron and both Q1 to Q4 and the borate group (BQ1Q2Q3Q4) are the same as in (C2). Specific examples of the Bronsted acid (JH) include trialkyl-substituted ammonium, N,N-dialkylanilinium, dialkylammonium, triarylphosphonium, and the like. Specific examples of the activator according to (C3) include, but are not limited to, triethylammonium tetrakis(pentafluorophenyl)borate, tripropylammonium tetrakis(pentafluorophenyl)borate, tri(n-butyl)ammonium tetrakis(pentafluorophenyl)borate, tri(n-butyl)ammonium tetrakis(3,5-bistrifluoromethyl-phenyl)borate, N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate, N,N-diethylanilinium tetrakis(pentafluorophenyl)borate, N,N-2,4,6-pentamethylanilinium tetrakis(pentafluorophenyl)borate, N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate, diisopropylammonium tetrakis(pentafluorophenyl)borate, dicyclohexylammonium tetrakis(pentafluorophenyl)borate, triphenylphosphonium tetrakis(pentafluorophenyl)borate, tri(methylphenyl)phosphonium tetrakis(pentafluorophenyl)borate, tri(dimethylphenyl)phosphonium tetrakis(pentafluorophenyl)borate, and the like.

[0073] Other cocatalysts include, but are not limited to, alkylaluminum, such as trialkylaluminum, trimethylaluminum, triethylaluminum, triisobutylaluminum, or tri-n-octylaluminum. Other examples include, but are not limited to, alkylaluminum halides, such as diethylaluminum chloride, dimethylaluminum chloride, and ethylaluminum sesquichloride, and aluminoxanes, such as methylaluminoxane (MAO), tetraisobutylaluminoxane (TIBAO), or hexaisobutylaluminoxane (HIBAO). Cocatalysts are also referred to as "activators" in the art. The presence of cocatalysts typically increases the rate at which the catalyst polymerizes olefins. Cocatalysts can also affect the molecular weight, degree of branching, comonomer content, or other characteristics of the polymer. Cocatalysts are typically introduced into the reactor together with the catalyst.

[0074] Cleaners :

[0075] Impurities may damage the catalyst by reducing the activity of the catalyst. Compounds that react with such impurities and convert them into compounds that are harmless to the activity of the catalyst are referred to as scavengers by those skilled in the art of polymerization. The scavenger may be fed to one or more reactors of the method disclosed herein. Non-limiting exemplary scavengers include alkyl aluminum compounds, such as trimethyl aluminum, triethyl aluminum, triisobutyl aluminum and trioctyl aluminum. The scavenger may be the same compound as the cocatalyst, and in that case, it is usually applied in an amount exceeding that required for fully activating the catalyst. The scavenger may also be introduced into the reactor together with the monomer feed or introduced into the reactor separately from the monomer feed via any other feed stream.

[0076] The scavenger can be used in combination with a hindered hydrocarbon, preferably a hindered phenol, containing heteroatoms of Group 15 or 16 (preferably O, N, P and S atoms, more preferably O and N heteroatoms). Specific examples of hindered hydrocarbons include, but are not limited to, tert-butyl alcohol, isopropanol, triphenylmethanol, 2,6-di-tert-butylphenol, 4-methyl-2,6-di-tert-butylphenol, 4-ethyl-2,6-di-tert-butylphenol, 2,6-di-tert-butylaniline, 4-methyl-2,6-di-tert-butylaniline, 4-ethyl-2,6-di-tert-butylaniline, diisopropylamine, di-tert-butylamine, diphenylamine, and the like.

[0077] method :

[0078] The method for producing the polymer comprises

[0079] (i) feeding a monomer stream containing monomers for producing a polymer into a polymerization unit comprising at least one reaction vessel, in which polymerization unit at least one reaction mixture comprising a polymer is produced in a polymerization reaction in the presence of at least one solvent and at least one catalyst,

[0080] (ii) feeding at least a portion of the reaction mixture comprising polymer, catalyst and optionally monomers produced in the polymerization unit into the recycle line to form a recycle stream comprising the reaction mixture,

[0081] (iii) reducing the temperature of the recirculation stream,

[0082] (iv) feeding the recycle stream after its temperature has been reduced to the polymerization unit, the monomer stream or both,

[0083] And wherein the process preferably further comprises a step (v) comprising feeding the reaction mixture produced in the polymerization unit to at least one post-treatment section to remove the solvent and isolate the polymer.

[0084] The process according to the present disclosure involves recycling at least a portion of the reaction mixture produced in the polymerization reactor. The reaction mixture for recycling is cooled and then directly or indirectly reintroduced into the reactor for further polymerization. This reduces the need to cool the monomer / solvent stream to very low temperatures, avoids the use of expensive cooling equipment and can reduce overall energy consumption. The recycling part of the polymerization process includes at least the following steps (ii), (iii) and (iv), which can be performed as a one-time step or repeatedly, for example continuously or intermittently, preferably continuously:

[0085] (ii) feeding at least a portion of the reactive reaction mixture containing the polymer produced in the polymerization unit into a recycle line to form a recycle stream for (re)introducing the reactive reaction mixture into the reaction vessel of the polymerization unit or into the monomer stream;

[0086] (iii) reducing the temperature of the recycle stream;

[0087] (iv) introducing the recycle stream into at least one reaction vessel of the polymerization unit, into the monomer stream, or a combination thereof, such as by dispersing the recycle stream.

[0088] The recycle stream can be directly introduced into the reaction vessel of the polymerization unit. Alternatively or additionally, the recycle stream can be indirectly introduced into the reaction vessel. For example, the recycle stream can be merged with the monomer stream to produce a reaction stream, and the recycle stream is fed into at least one reaction vessel as a part of the reaction stream. The recycle stream contains the reaction mixture produced in the polymerization unit. The reaction mixture contains a polymer and a catalyst. The reaction mixture fed into the recycle stream can contain at least 5% by weight of the polymer based on the total weight of the reaction mixture. In one embodiment of the present disclosure, the reaction mixture fed into the recycle stream contains 5% to 15% by weight of the polymer. The reaction mixture in the recycle stream may optionally also contain a monomer, and optionally also contain a solvent. The reaction mixture in the recycle stream contains a catalyst and is still reactive. The polymerization reaction can continue in the recycle stream, although the polymerization reaction may be suppressed or its reaction rate may be reduced, for example, by adding one or more chain transfer agents to the recycle stream, or by increasing the flow rate of the recycle stream or the length of the recycle line.

[0089] Now we will refer to Figure 1 The method according to the present disclosure is described in more detail for illustration:

[0090] A monomer stream (1) containing monomers for making ethylene / α-olefin copolymers is produced. Preferably, the monomer stream (1) is a single stream and preferably contains all different types of monomers required for producing the copolymer. Instead of a single monomer stream, several identical or different monomer feed streams can also be used. Preferably, the monomer stream also contains a solvent. Preferably, the monomer and the solvent are fed together in one feed stream into the polymerization (4) unit. The first monomer feed stream (1) may also contain one or more chain transfer agents or both. In one embodiment of the present disclosure, all fresh solvent is introduced into at least one reaction vessel as part of the monomer stream. The first monomer feed stream (1) is cooled to a first temperature T1. Typically, T1 may include a temperature of -30° to +39°C, or greater than -25°C and up to +39°C. Preferably, T1 is -15°C and up to +25°C or -10°C to +20°C. Preferably, the monomer stream is pressurized to maintain the monomer in a liquid state and / or dissolved in a solvent.

[0091] The monomer feed stream (1) is introduced into the polymerization unit (4). The polymerization unit is a process section for producing polymers. The polymerization unit may contain one or more than one reaction vessel, and a polymerization reaction may be carried out in each reaction vessel. In the case of using multiple reaction vessels, these vessels may be connected in series or in parallel or in a combination thereof. The reaction vessel has at least one device for mixing the reactor contents or at least a portion of the reactor contents. Typical reaction vessels include stirred tank reactors, preferably continuous stirred tank reactors (CSTRs), which means that the reactor contents are continuously stirred during the polymerization reaction. Such reactors are known in the art. Typically, a stirred tank reactor is a pressure reactor vessel comprising one or more rotating agitators and / or one or more impellers, preferably on a central agitator shaft, for mixing the reactor contents. Examples of impellers include, but are not limited to, INTERMIG, VISCOPROP and VARIOBLADE from Ekato Systems GmbH. Typically, one or more baffles are usually installed on the wall of the reactor to improve the mixing quality. However, in addition to stirred tank reactors, other types of reaction vessels with mixing elements suitable for solution or slurry polymerization can also be used. The method can be used on a small scale or on an industrial scale, wherein preferably, at least one reactor with a reactor volume greater than 3 liters, for example with a volume of about 4 to 4000 liters, is used. Preferably, when operating on an industrial scale, the polymerization unit has at least one reactor with a reactor volume of about 4 to 4000 liters, and the method is operated continuously. Typically, one or more feed streams (1) introduce reactants into at least one reaction vessel, and an outlet stream (5) is used to extract the reactor effluent. Typically, chain transfer agents, solvents, catalysts, and monomer feeds are introduced at one or more points in the reaction vessel using various types of feed injectors. Typically, one or more catalyst components are introduced in a similar manner via one or more catalyst injectors and separately from the monomers. Chain transfer agents and solvents can be introduced separately from the monomer stream, but are preferably pre-added to the monomer stream and introduced into the reactor as a component of the monomer stream. Scavengers are preferably introduced via the monomer stream (1). In the case of connected reaction vessels, the reaction mixture from one reaction vessel may be fed to the other reaction vessel instead of or in addition to the fresh monomer stream.

[0092] Mixers are often used downstream of each feed or catalyst injector to improve mixing of these feed streams with the bulk fluid.

[0093] These reactors can be jacketed to allow the addition or removal of heat. The reactor can include cooling coils to help remove the heat of polymerization. Preferably, the reactor is operated adiabatically. When the reactor is operated adiabatically, it is limited to not removing or adding heat by internal or external heating or cooling devices. For example, less than 20%, less than 10% or even 0% of the temperature in the reactor is generated (or removed or both) by external or internal heating or cooling devices. On the contrary, the temperature in the reactor is completely or mainly controlled by the exothermic reaction, the temperature and flow rate of the reactants and effluents, the temperature and flow rate of one or more reactant streams entering the reactor, the residence time in the reactor, and the temperature and flow rate of the effluent leaving the reactor, or a combination thereof. Typically, the condensation of the gas phase produced in the reactor is not used to remove heat from the reaction vessel. Preferably, the reactor is operated so as to prevent the formation of condensable monomer gas, that is, the reactor is operated so that the monomer remains dissolved in the solvent or remains liquid. For example, the reactor can contain a sufficient amount of solvent and can be operated under sufficient pressure to prevent the formation of monomer gas. For example, the reactor can be filled with at least 50%, or at least 75%, preferably at least 90% or even 95% of solvent or liquid based on the available reactor volume, typically including components such as reactants, solvents and reaction products in liquid, dissolved, suspended or dispersed form. Preferably, the polymerization unit and the recycle line are operated at sufficient pressure so that the (unused and fresh) monomers remain dissolved in the solvent or remain liquid or both. In one embodiment of the present disclosure, the solvent also remains liquid in the reactor.

[0094] In the process according to the present disclosure, the polymerization unit (4) comprises at least one reaction vessel, which is preferably operated as a stirred tank reactor. Typically, during the polymerization, a temperature T4 of about 50° C. to 160° C., or 60° C. to 120° C., may be reached in at least one reaction vessel of the polymerization unit. This temperature is suitable for the polymerization rate and the polymer to be produced and may depend on the reaction system used. However, the process is run such that the temperature in the reaction vessel where the polymerization is carried out is below the temperature at which the catalyst used in the polymerization is deactivated.

[0095] The residence time of the reactants in the polymerization unit (4) is suitable to produce a reaction mixture containing the desired amount of the desired polymer. In addition to the polymer, the reaction mixture may comprise a solvent and may also comprise unreacted monomers and optionally chain transfer agents, catalysts and further components.

[0096] The outlet stream (5) (also referred to herein as the "product stream") removes the reactor effluent containing the reaction mixture obtained by the polymerization reaction. The reaction mixture can be fed to a subsequent reactor for further polymerization with or without the addition of fresh monomers and / or with or without the addition of fresh or different catalysts, or the reaction mixture can be sent directly to at least one post-treatment section (6) without passing through other reactors, in which the polymer is separated from the reaction mixture. The post-treatment section (6) can contain a devolatilization unit in which the solvent is removed, for example, by one or more stripping towers. The post-treatment unit can include one or more containers, pumps and mixers for post-treating the polymer or for mixing additional ingredients (such as, for example, extender oil or other additives). The solvent and unreacted monomer can be recycled and reused in the polymerization process. Before entering the post-treatment section (6), or within the post-treatment section (6), the catalyst contained in the outlet stream (5) can be killed by adding polar components such as water, alcohol, acid, ester, O2, CO, CO2 or any component known to react with the catalyst and stop polymerization. If an oil-extended polymer is produced as is known in the art, one or more extender oils may be added to the reaction mixture prior to solvent removal. Suitable extender oils include, but are not limited to, petroleum oils such as aromatic and naphthenic oils; polyalkylbenzene oils; organic acid monoesters such as alkyl and alkoxyalkyl oleates and stearates; organic acid diesters such as dialkyl, dialkoxyalkyl and alkylaryl phthalates, terephthalates, sebacates, adipates, and glutarates; glycol diesters such as triethylene glycol dialkanoate, tetraethylene glycol dialkanoate, and polyethylene glycol dialkanoate; trialkyl trimellitates; trialkyl phosphates, trialkoxyalkyl phosphates, alkyl diaryl phosphates, and triaryl phosphates; chlorinated paraffin oils; coumarone-indene resins; pine tar oils; vegetable oils such as castor oil, tall oil, rapeseed oil, and soybean oil, and their esters and epoxidized derivatives; and the like.

[0097] At least a portion of the reaction mixture produced in the polymerization unit (4) is fed as a recycle stream (2) into at least one recycle line. For example, 1% to 95% or 10% to 50% (volume percentages based on the total volume of the reaction mixture) of the reaction mixture can be used for recycle. The portion of the reaction mixture used for recycle can be taken directly from the reactor or, for example, Figure 1As shown, or it can be taken out from the product stream (5) before the catalyst killing / deactivating additive is added to the product stream. In one embodiment, the recycle stream (2) is taken out from the product stream. 1% to 95%, preferably 10% to 50% (volume percentage based on the total volume of the product stream) of the product stream can be taken out for the recycle stream. In one embodiment of the present disclosure, the recycling process is operated intermittently and 100% of the product stream is used for at least one recycle cycle. The recycle stream (2) is fed to a cooling unit and then fed to a monomer stream or a reaction vessel or a combination thereof in at least one recycle line. The recycle line may include one or more pumps for advancing the recycle stream (2) through the recycle line. Pumps known in the art can be used to transport the polymerization mixture. Propulsion can also or additionally be achieved by using a pressure difference or other means known in the art. The recycle line typically has a diameter less than the diameter of the reaction vessel. The total volume of the recycle line may be less than or greater than the reactor volume of at least one reaction vessel, or the volume may be the same.

[0098] The reaction mixture can be removed from the reactor and / or product pipeline for continuous or discontinuous recycling. For example, the reaction mixture can be subjected to recycling only at certain intervals. The product stream can be fed to the post-processing section (6) continuously or discontinuously. For example, the product stream to the post-processing section (6) can be interrupted at intervals, and can be used for recycling alternatively. Preferably, the method is continuously operated, and the product stream (5) and the recycle stream (2) are all continuously operated.

[0099] In one embodiment of the method according to the present disclosure, steps (ii) to (iv) are performed once or more than once before subjecting the reaction mixture produced in the polymerization unit to post-treatment to remove the solvent and separate the polymer. This can be performed in a batch process, but can also be performed in a continuous process. In one embodiment of the present disclosure, the recycling steps (ii) to (iv) can be performed simultaneously with step (v), for example in a continuous process, and the step (v) includes feeding the reaction mixture produced in the polymerization unit to at least one post-treatment unit to remove the solvent and separate the polymer. In one embodiment of the method according to the present disclosure, the recycling steps (ii), (iii) and (iv) are performed at least once or more than once before performing step (v).

[0100] Before the recycle stream is introduced directly or indirectly into the polymerization unit to participate in the polymerization reaction, the temperature of the recycle stream (2) is reduced in the cooling unit (8). In the cooling unit (8), the temperature of the recycle stream (2) can be reduced by one or more cooling devices. Preferably, the cooling unit (8) contains at least one heat exchanger. A single heat exchanger or a plurality of heat exchangers that can be connected in series or in parallel can be used. Instead of a heat exchanger, or in addition to a heat exchanger, one or more other devices for reducing the temperature can be used, but a heat exchanger is preferred. Before its temperature is reduced, the recycle stream (2) can have a temperature approximately the same as the reaction vessel from which it comes. For example, before cooling in the cooling unit (8), the recycle stream (2) can have a temperature T4 of about 60°C to about 120°C. In the cooling unit (8), the temperature of the recycle stream (2) is reduced to a temperature T2. Typically, the temperature T2 of the recycle stream (2) is lower than the temperature of the reaction vessel of the polymerization unit to which the recycle stream (2) will be fed. Temperature T2 may be the same as temperature T1 of monomer stream (1), or it may be greater than temperature T1 or it may be lower than temperature T1. Examples of temperature T2 include, but are not limited to, temperatures of 10°C to 90°C. In one embodiment of the present disclosure, the temperature of the recycle stream (2) is reduced to a temperature T2 between 20°C and 85°C. After the recycle stream (2) is cooled to temperature T2, it is introduced directly or indirectly into the polymerization unit. This may be done in different ways. Figure 1 In the embodiment shown, the recycle stream is combined with the monomer stream (1) to produce the reactant stream (3). The recycle stream is then indirectly introduced as part of the reactant stream (3) into at least one reaction vessel of the polymerization unit (4) to produce the polymer. Alternatively or additionally, the recycle stream (2) may be fed directly into the reaction vessel of the polymerization unit (4) to produce the polymer without being combined with the monomer stream (1).

[0101] exist Figure 1In the embodiment shown, the recycle stream (2) is combined with the monomer stream (1) after its temperature has been reduced to a temperature T2 and before it is fed into the reaction vessel of the polymerization unit (4) together with the monomer stream as a reactant stream (3). In this embodiment of the present disclosure, the temperature of the recycle stream (2) can be reduced to a temperature (T2) of about 20°C to 80°C before it is combined with the monomer stream (1), which is lower than the temperature at which the reaction vessel to which the reactant stream is fed operates. The temperature T2 in this embodiment is higher than the temperature (T1) of the monomer stream (1). Typically, the monomer stream according to the method of the present disclosure has a temperature T1 that can be greater than -25°C and up to +39°C. In one embodiment of the present disclosure, the monomer stream has a temperature T1 of -15°C and up to +25°C or -10°C to +20°C. In one embodiment of the present disclosure, the temperature of the recycle stream (2) has been reduced to a temperature (T2) of about 20°C to 80°C, at which temperature the recycle stream is combined with the monomer stream (1) or introduced directly into the reactor vessel, or both, and wherein the temperature of the monomer stream (T1) is greater than -25°C and up to +39°C, and preferably, T1 is -15°C and up to +25°C or -10°C to +20°C.

[0102] exist Figure 1 In the embodiment shown, the recycle stream (2) is combined with the monomer stream (1). By mixing the monomer stream and the recycle stream, the resulting reaction stream (3) can reach a temperature T3 before it enters the reaction vessel of the polymerization unit (4). Typically, the temperature T3 of the reaction stream (3) is greater than the temperature T1 of the monomer stream (1). Typically, when the recycle stream (T2) is combined with the monomer stream (1), the temperature T3 is lower than the temperature of the recycle stream, and typically, T3 is lower than the temperature of the reaction vessel operation to which the reaction stream (3) is fed. Temperature T3 can be, for example, 10°C to 90°C. The temperature of the reaction stream (T3) can be regulated by measures including controlling the volume and / or flow rate of the monomer (1) and the recycle stream (2) and controlling the temperatures T1 and T2. Additionally or alternatively, the temperature T3 of the reaction stream (3) can be increased or decreased by an external device such as a heat exchanger, a heating unit or a cooling unit, but this may not be necessary and may be undesirable due to the additional energy cost.

[0103] The recycle stream (2) may include polymer, unreacted monomer, catalyst and activator, and may be reactive. The polymerization reaction may continue in the recycle stream (2). The recycle stream may include polymers such as 5% to 15% by weight, 1% to 10% by weight or 2% to 20% by weight based on the total weight of the recycle stream. However, although the polymerization in the recycle stream may be tolerated or desired to continue due to the recycle stream being reintroduced into the polymerization unit, it is preferred that the polymerization in the recycle line is suppressed, reduced or slowed down because it may cause blockage and reactor fouling in the recycle line and in particular in the cooling unit. This may be achieved by various measures that may be taken individually or in combination. Preferably, additional catalyst, activator or both are added to the recycle stream (2) at least until the recycle stream (2) has passed through the cooling unit (8). Preferably, the residence time of the recycle stream (2) is shorter than the residence time in the polymerization unit (4). The residence time of the recycle stream (2) may be shorter than the residence time of the polymerization unit (4) by, for example, 1.5 to 150 times. The residence time of the recycle stream (2) is measured between the point where the reaction mixture is withdrawn for recycle and fed into the recycle line to the point where the recycle stream is introduced into the reaction vessel of the polymerization unit or to the point where the recycle stream is combined with the monomer stream. The residence time of the polymerization unit is measured from the point where the monomer stream enters the first reaction vessel of the polymerization unit until the point where the final polymer leaves the reaction vessel. The residence time can be experimentally calculated or measured by methods such as those known in the art. Preferably, the flow rate of the recycle stream (2) is faster than the flow rate of the monomer stream (1). In one embodiment of the present disclosure, the flow rate of the recycle stream (2) may be at least 1.5, for example 1.5 to 15 times faster than the flow rate of the monomer stream (1). The recycle line may contain one or more pumps to control or regulate the flow rate of the recycle stream (2). Alternatively or additionally, one or more chain transfer agents (CTA) may be added to the recycle stream (2) to reduce or completely inhibit the formation of long polymer chains. Preferably, the additional chain transfer agent is introduced via a Figure 1 An optional CTA feed stream (7) is shown fed to the recycle stream (2). Preferably, a chain transfer agent (CTA) is added to the recycle stream (2) before or while the recycle stream (2) is cooled in the cooling section (8). The chain transfer agent added to the feed stream (7) can be the same chain transfer agent that can be added to the monomer stream (1), or it can be a different CTA. If the chain transfer agent is added to the recycle stream, it can be introduced into the polymerization unit (4) together with the recycle stream (2) or the reaction stream (3). Therefore, the total amount of CTA in the recycle stream must be considered, and when the chain transfer agent is added to the recycle stream, it may be necessary to adjust, for example reduce or stop the new addition of CTA to the monomer stream (1) or the reaction unit (4).

[0104] In a process in which the reaction vessels are connected in series, the reaction mixture produced in the first reactor vessel and comprising the first polymer can be fed into at least the second reaction vessel to produce at least a second reaction mixture comprising the second polymer. The volumes of these containers can be the same or different. The residence time in the containers can also be the same or different. The mixers in the containers can be the same or different, and the mixing speeds can be the same or different. For the recycle portion of the process, the first reaction mixture or at least the second reaction mixture or both can be used. Such a process allows, for example, the production of unimodal polymers and multimodal polymers when, for example, different catalysts are used in the first and second reaction vessels. Figure 2 and Figure 3 An embodiment of a process according to the present disclosure is shown having reactors connected in series.

[0105] Figure 2 The method shown in Figure 1 The method is the same as shown in, except that the polymerization unit (4) comprises a first reaction vessel (4a) and a second reaction vessel (4b). The effluent (5a) produced in the first reaction vessel (4a) and comprising the first reaction mixture containing the polymer is fed to the second reaction vessel (4b) for further polymerization. In one embodiment of the present disclosure, one of the following items is added to the second reaction vessel (4b): the reaction mixture obtained in the first reaction vessel, fresh monomers, fresh solvents, catalysts, and optional ingredients or a combination thereof. In another embodiment of the present disclosure, only the effluent of the first reaction vessel (4a) is added to the second reaction vessel, and the polymerization is continued in the second container. The effluent (5b) of the second reaction vessel contains the final polymer and is fed to the post-treatment unit (6). Instead of as Figure 2 The two reaction vessels shown in , more than two reaction vessels can be connected in the same manner. A portion of the effluent (5b) is directed in the recycle line stream (2) via a cooling unit (8) to the monomer stream (1) and combined with the monomer stream to form a reaction stream (3), which is introduced into the first reactor (4a) for further polymer production. A chain transfer agent can be added to the recycle stream (2) via a CTA feed (7) before or simultaneously with the recycle stream (2) entering the cooling unit (8). Instead of Figure 2In the case where the recycle stream (2) is fed into the monomer stream (1), the recycle stream (2) may alternatively or additionally be fed directly into the first reactor (4a) or the effluent (5a) or directly introduced into the second reactor vessel (4b). Alternatively or additionally, the recycle stream (2) may not be merged with the monomer stream (1) and may be fed directly into the reaction vessel, for example, into the reaction vessel (4a) or the reaction vessel (4b) or both. The recycle stream (2) may be continuously or intermittently fed into (4a) for some time and fed into (4b) for some time. Instead of or in addition to taking out the recycle stream (2) from the effluent (5b), the recycle stream may also be taken out from the effluent (5a) or both. In another embodiment, two separate recycle streams are produced, one from the effluent (5a) and the other from the effluent (5b). They may be fed via separate recycle lines or may be combined in a single recycle line and introduced into vessel (4a), vessel (4b) or both, or into the monomer stream, or one of the recycle streams may be combined with the monomer feed stream (1) and the other fed directly to the reaction vessel.

[0106] Figure 3 An embodiment of a process according to the present disclosure is shown wherein the recycle stream (2) is withdrawn from the effluent (5a) of the first reaction vessel (4a) before it enters the second reaction vessel (4b).

[0107] Instead of using reaction vessels in series, the reaction vessels of the polymerization unit (4) can also be arranged in parallel. The reactor effluents can be combined, for example in a mixer or in another reactor, before or during solvent removal and work-up of the polymers. Such an arrangement allows, for example, the production of multimodal polymers or polymer blends, such as "reactor blends", i.e. polymer blends obtained by wet mixing.

[0108] The recycle stream (2) can be generated from the reaction mixture of one or more than one or all reaction vessels or from the combined effluent before the combined effluent enters the devolatilization unit and before the catalyst is killed. The recycle stream can be directed to one or all reaction vessels. An example of such a parallel reactor process is shown in Figure 4 The first part of the method is in principle the same as Figure 1 The process is the same as that shown in , however, a second monomer feed (1') is introduced into the second polymerization unit (4') and a product stream (5') is produced. The product stream (5') is combined with the product stream (5) from the first polymerization unit (4) and is advanced to a post-treatment section (6). Before the product stream (5) is combined with the product stream (5'), the reaction mixture from the effluent is used for recycling. Figure 4The process shown in uses only one recycle stream for the first polymerization unit. In one embodiment of the process, polymerization units (4) and (4') can each have their own recycle streams (2) and (2') taken from effluents (5) and (5'), respectively. As described above, the one or more recycle streams can be fed directly to one or more reaction vessels of polymerization units (4) or (4') or both, after or without being combined with monomer feed (1) or (1').

[0109] Examples

[0110] The present disclosure will now be further illustrated by way of examples, without intending to limit the present disclosure to the particular examples presented.

[0111] Test method:

[0112] Polymer composition:

[0113] The composition of the copolymers was determined using Fourier transform infrared spectroscopy (FT-IR) according to ASTM D3900 (revised 2017) for the C2 / C3 ratio and D6047 (revised 2017) for the diene content on pressed polymer films.

[0114] Phase angle measurement:

[0115] Polymer branching is determined by measuring the phase angle with the parameter Δδ on a Montech MDR 3000 moving die rheometer. Δδ (expressed in degrees) is the difference between the phase angle δ measured at a frequency of 0.1 rad / s and the phase angle δ measured at a frequency of 100 rad / s, determined by dynamic mechanical analysis (DMA) at 125°C. Δδ is a measure of the presence of long chain branches in the polymer structure. The lower the value of Δδ, the more long chain branches are present in the polymer, and is introduced by HC Booij in Kautschuk+GummiKunststoffe [Raw Rubber, Rubber and Plastics], Vol. 44, No. 2, pp. 128-130, 1991, which is incorporated herein by reference.

[0116] Molecular Weight:

[0117] Molecular weight (Mw, Mn, Mz) and molecular weight distribution (MWD) can be measured by gel permeation size exclusion chromatography (GPC) using a Polymer Char GPC-IR from Polymer Characterization SA, Valencia, Spain. The size exclusion chromatograph was equipped with an online viscometer (Polymer Char V-400 viscometer), an online infrared detector (IR5 MCT) and 3 AGILENT PL OLEXIS columns (7.5 x 300 mm) and a Polymer Char autosampler. The system was universally calibrated with polyethylene (PE) standards.

[0118] The polymer samples were weighed (concentration range 0.3-1.3 mg / ml) into vials of the PolymerChar autosampler. In the autosampler, these vials were automatically filled with solvent (1,2,4-trichlorobenzene stabilized with 1 g / l di-tert-butyl-p-cresol (DBPC)). The samples were kept in a high temperature oven (160°C) for 4 hours. After this dissolution time, the samples were automatically filtered through an in-line filter before injection into the column. The chromatograph system was operated at 160°C. The flow rate of the 1,2,4-trichlorobenzene eluent was 1.0 mL / min.

[0119] Mooney viscosity:

[0120] The Mooney viscosity of the copolymer samples was measured according to ISO 289 (revised 2015) using a biaxially strained PP (20 μm thick) film supplied by Perfon BV, Goor, The Netherlands. The measurement conditions were ML (1+4) at 125°C.

[0121] polymerization:

[0122] The polymerization to produce the EPDM polymer was generally carried out as described in the section "General Polymerization Procedure" of WO 2005 / 090418 A1, which is incorporated herein by reference. Triisobutylaluminum was used instead of MAO-10T. The experimental setup was essentially as Figure 2As shown, two liquid-filled stirred tank reactors for solution polymerization are connected in series. Two reactors (4a) and (4b) have a volume of 3 liters. This setting is used as a proof of principle experiment. Since it has been found that the reactor volume is not critical, it is believed that the method can also be carried out in a larger reactor with a reactor volume greater than 3 liters, for example, in a reactor with a volume of 4 to 4000 liters. Monomer and solvent are fed together in a pipeline (monomer flow (1)) into the first reaction vessel (4a). Catalyst and activator are fed into the first reactor (4a) in a separate pipeline. The effluent (5a) of the first reactor (4a) is fed into the second reactor (4b), and in addition to the effluent, no other feed is introduced into the second reactor (4b). A portion of the reactor effluent of the second reactor is fed into the post-processing unit (6) by the discharge line (5b), and the other portion is fed into the recirculation line (2). The recycle line (2) is pumped through the heat exchanger of the cooling unit (8) to reduce its temperature. The recycle line (2) is then combined with the feed line (1) to produce a reaction stream (3) which enters the first reactor (4a) of the polymerization unit (4). Hydrogen is added to the feed line (1) as a chain transfer agent. The amount of hydrogen is adjusted to achieve the desired polymer Mooney viscosity as given in Table 1. Figure 2 In contrast to what is shown in , no chain transfer agent (7) is added to the recycle stream.

[0123] The feed stream is purified by contacting it with various absorption media to remove impurities that kill the catalyst, such as water, oxygen, and polar compounds, and the process is continuous in all feed streams. The premixed solvent (a mixture of hexane isomers with a boiling point range of 65°C to 70°C), propylene, ethylene, ENB and VNB, hydrogen, and scavengers are precooled before feeding to the reactor. The solution containing the catalyst and activator is fed separately to the reactor. The solvent feed rate is 29.1 liters / hour; the ethylene feed rate is 30.2 mol / hour, the propylene feed is 27.1 mol / hour, and the ENB feed is 966 mmol / hour. The pressure is 20 bar (gauge pressure). Polymerization is started by loading the catalyst and activator into the system. The recycle flow is set at twice the feed rate. The feed rate is the sum of the monomer and solvent mass flow rates.

[0124] The polymer solution (reaction mixture) is continuously removed from the second reactor through a discharge line (5b) in which a portion of the reaction mixture is fed into a recirculation line (2) and the remainder of the reaction mixture is fed into a post-treatment vessel in which a solution of IRGANOX 1076 in isopropanol is added to terminate further polymerization and stabilize the polymer. Residual monomers and solvent are removed by continuous steam stripping, producing polymer crumbs. The EPDM polymer obtained is batch dried on a mill. The composition of the EPDM polymer obtained by this process and further processing conditions are shown in Table 1.

[0125] Table 1: Aggregation details.

[0126] parameter result Temperature of monomer and solvent feed [°C] 9.9 Temperature of the first reactor [℃] 89.8 Temperature of the second reactor [°C] 93.9 Temperature of the recirculation stream after the heat exchanger 72.2 Product[g / h] 1237 C2 conversion rate [%] 93 <![CDATA[H2[NL / h]]]> 0.03 VNB[mmol / h] 35 Total solids discharged from reactor 2 [%] 10.8 Mooney (ML 1+4, 125°C) [MU] 52 C2 in polymer [wt%] 47.7 ENB in ​​polymer [wt.%] 5.3 VNB in ​​polymer [wt. %] 0.15 Δδ[°] 13.8 Mn[kDa] 61 Mw[kDA] 245 Mz[kDa] 760

[0127] In Table 1, "Prod" means polymer production rate in g / h, "C2" means units derived from ethylene. The remainder of the EPDM polymer (except units derived from C2, ENB and VNB) consists of units derived from propylene.

[0128] As shown above, EPDM polymers having a weight average molecular weight greater than 200.000 g / mole are produced with a monomer / solvent feed stream that must only be cooled to 10°C, and thus only moderate cooling of the monomer and solvent is required.

Claims

1. A method for producing a polymer, the method comprising (i) feeding a monomer stream containing monomers for producing the polymer into a polymerization unit comprising at least one reaction vessel, in which polymerization unit at least one reaction mixture comprising the polymer is produced in a polymerization reaction in the presence of at least one solvent and at least one catalyst, (ii) feeding at least a portion of the reaction mixture comprising polymer, catalyst and optionally monomers produced in the polymerization unit into a recycle line to form a recycle stream, (iii) reducing the temperature of the recycle stream, (iv) feeding the recycle stream after its temperature has been reduced to the polymerization unit, the monomer stream or both, and wherein the polymer is an elastomer selected from the group consisting of: (a) ethylene / α-olefin copolymers having at least 20 wt. % of units derived from ethylene and which optionally may further comprise units derived from at least one non-conjugated diene having 6 to 30 carbon atoms, preferably selected from the group consisting of dicyclopentadiene (DCPD), 5-ethylidene-2-norbornene (ENB), 5-vinyl-2-norbornene (VNB) and combinations thereof, (b) polybutadiene and (c) butadiene copolymers having at least 50 wt. % of units derived from butadiene, wherein preferably at least one reaction vessel of the polymerization unit has a reactor volume of at least 4 liters, and wherein the process preferably further comprises a step (v) comprising removing the solvent from the reaction mixture produced in the polymerization unit and isolating the polymer, preferably by feeding the reaction mixture produced in the polymerization unit to at least one post-treatment section to remove the solvent and isolate the polymer.

2. The method according to any one of claims 1 or 2, comprising repeating steps (ii) to (iv) continuously or intermittently.

3. A method according to any one of the preceding claims, wherein: Steps (ii) to (iv) are performed once or more than once before subjecting the reaction mixture produced in the polymerization unit to a post-treatment to remove the solvent and isolate the polymer.

4. A method according to any one of the preceding claims, wherein: The flow rate of the recycle stream is faster than the flow rate of the monomer stream.

5. A method according to any one of the preceding claims, wherein: The residence time of the recycle stream, determined from the point at which the reaction mixture is fed into the recycle line to form the recycle stream to the point at which the recycle stream enters the monomer stream or the reaction vessel, is shorter than the residence time of the polymerization unit, determined from the point at which the monomer stream enters the reaction vessel to the point at which the effluent of the reaction vessel leaves the reaction vessel for polymer post-processing.

6. A method according to any one of the preceding claims, wherein: The temperature of the recirculation stream is reduced in a cooling unit comprising at least one heat exchanger.

7. A method according to any one of the preceding claims, wherein: The temperature of the recycle stream is reduced in a cooling unit and no additional catalyst or activator or both are added to the recycle stream before it passes through the cooling unit, and preferably no additional catalyst or activator or both are added to the recycle stream at all.

8. A method according to any one of the preceding claims, wherein: After the temperature of the recycle stream is reduced, the temperature of the monomer stream is lower than the temperature of the recycle stream, and wherein the temperature of the monomer stream is greater than -25°C and up to 39°C, preferably -15°C and up to 25°C.

9. A method according to any one of the preceding claims, wherein: The temperature in at least one stirred tank reactor during the polymerization reaction was between 60°C and 120°C.

10. A method according to any one of the preceding claims, wherein: The monomer stream comprises monomer and solvent.

11. A method according to any one of the preceding claims, wherein: The polymerization unit comprises at least a first reaction vessel, preferably a stirred tank reactor, and at least a second reaction vessel, preferably a stirred tank reactor, which can be connected in series or in parallel, wherein in the first reaction vessel a first reaction mixture is produced in a polymerization reaction in the presence of at least one solvent and at least one catalyst, and in the second reaction vessel a second reaction mixture is produced in a polymerization reaction in the presence of a solvent and at least one second catalyst, and wherein the recycle stream comprises at least a portion of the first reaction mixture or at least the second reaction mixture or both, and wherein the first polymerization catalyst is the same as the second polymerization catalyst or is a different catalyst.

12. The method according to any one of the preceding claims, comprising adding a chain transfer agent to the recycle stream, preferably before reducing the temperature of the recycle stream in a cooling unit, and wherein the addition of the chain transfer agent is continuous or intermittent or is a single dose addition.

13. A method according to any one of the preceding claims, wherein: At least the at least one reaction vessel is pressurized to keep the monomers dissolved or in a liquid state.

14. A method according to any one of the preceding claims, wherein: The polymer is an ethylene / α-olefin copolymer comprising units derived from ethylene and propylene, preferably having a weight average molecular weight of at least 50,000 g / mole, more preferably at least 200,000 g / mole as determined by gel permeation chromatography, and wherein the copolymer preferably further comprises units derived from at least one non-conjugated diene having 6 to 30 carbon atoms, the non-conjugated diene preferably being selected from dicyclopentadiene (DCPD), 5-ethylidene-2-norbornene (ENB), 5-vinyl-2-norbornene (VNB) and combinations thereof.

15. A method according to any one of the preceding claims, wherein: The polymerization is carried out as a slurry polymerization or a solution polymerization.

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