Method for producing a polymer

Abstract

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

Description

Technical Field

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

Background Art

[0002] Many widely used synthetic rubbers are produced by solution polymerization or slurry polymerization using one or more polymerization catalysts. To optimize the mixing of the catalyst and reactants, the polymerization is usually carried out in a stirred tank reactor. The polymerization reaction is generally exothermic, and the catalyst deactivates when the temperature exceeds a certain threshold value. Therefore, the temperature in the reactor needs to be controlled to keep it below the temperature at which the catalyst deactivates. Cooling of the reactor by an external or internal cooling device may cause, for example, deterioration of reaction control and reactor fouling as described in (Patent Document 1). Continuous polymerization is usually carried out in a so-called adiabatic reactor, and the temperature of the reactor is mainly set by the concentration of the target polymer and the temperature of the feed stream of the monomer / solvent mixture. Usually, the monomer feed is cooled to a temperature much lower than 0 °C in one or more cooler units before entering the reactor. At this time, the temperature in the reaction vessel is desirably maintained at a fixed predetermined value within the range of about 60 °C to 120 °C so that the polymerization proceeds to form a high molecular weight polymer while avoiding catalyst deactivation. However, cooling the monomer / solvent feed to a low temperature consumes energy and greatly affects the production cost. In the process described in (Patent Document 1), the polymerization is carried out in a boiling state in a polymerization reactor. The temperature of the reactor is controlled using the cooling effect of the evaporation stream in the reactor. The vapor phase from the reactor is supplied into a condenser, cooled to a low temperature in a subcooler, and then combined with a fresh monomer / solvent feed stream and supplied back into the reactor. However, operating the reactor in a boiling state is also not very economical because only a part of the reactor volume can be used for polymerization. Furthermore, the energy cost increases due to the condensation of the vapor phase. (Patent Document 2) describes a polymerization process using at least two reactors, at least one of which is a loop reactor. A cooling stream containing monomer, solvent, and hydrogen is supplied to the first reactor, where a reaction mixture containing polymer is produced. The reaction mixture is supplied to the loop reactor, where fresh cooled monomer, solvent, and hydrogen are added. The catalyst is supplied to the loop reactor, and a second polymerization is carried out in the loop reactor.The process has been reported to reduce the load on a devolatization unit that removes the solvent from the reaction mixture to isolate the polymer, and it has been reported to save energy costs. Thus, energy savings are achieved in this process during the post-treatment stage after the polymerization has been carried out. In (Patent Document 3) and (Patent Document 4), it is suggested that polymerizing the feedstock in a loop reactor to produce a polyolefin product improves heat transfer compared to a stirred tank reactor. A loop reactor is generally described as several loop-shaped heat exchangers. The examples described in these documents are software simulations.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0004] There remains a need for an alternative process for producing polymers at lower energy costs by polymerization using at least one solvent and at least one catalyst. Preferably, the process is suitable for producing polymers having a high weight average molecular weight, for example, a weight average molecular weight of at least 50 kg / mol or at least 200 kg / mol.

Means for Solving the Problems

[0005] Therefore, a process for producing a polymer, wherein the process for producing the polymer (i) supplying a monomer stream containing monomers for producing the polymer into a polymerization apparatus including at least one reaction vessel, wherein at least one reaction mixture containing the polymer is produced by a polymerization reaction in the presence of at least one solvent and at least one catalyst; (ii) supplying at least a part of the reaction mixture produced in the polymerization apparatus, which contains the polymer, the catalyst and optionally the monomer, into a recycle line to form a recycle stream; (iii) lowering the temperature of the recycle stream; (iv) supplying the recycle stream into the polymerization apparatus, the monomer stream, or both, after the temperature of the recycle stream has been lowered, comprising wherein the polymer is an elastomer selected from (a) an ethylene / α-olefin copolymer having at least 20% by mass of units derived from ethylene, optionally further containing units derived from at least one non-conjugated diene having 6 to 30 carbon atoms, preferably units derived from at least one non-conjugated diene having 6 to 30 carbon atoms selected from dicyclopentadiene (DCPD), 5-ethylidene-2-norbornene (ENB), 5-vinyl-2-norbornene (VNB) and combinations thereof, (b) polybutadiene, and (c) a butadiene copolymer having at least 50% by mass of units derived from butadiene; preferably, at least one reaction vessel of the polymerization apparatus has a reaction vessel volume of at least 4 liters, and The process preferably further comprises step (V) which involves removing the solvent from the reaction mixture produced in the polymerization apparatus and isolating the polymer, and preferably the removal of the solvent and the isolation of the polymer are carried out by feeding the reaction mixture produced in the polymerization apparatus to at least one post-treatment section for removing the solvent and isolating the polymer. A process is provided.

Brief Description of Drawings

[0006]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0007] The process according to the present disclosure will be further described in more detail in the following description.

[0008] In the following description, the terms "comprising", "containing", "including", "having" are not intended to exclude the presence of any additional components, steps, or procedures, whether or not specifically disclosed. The term "consisting of" is used when it is meant to exclude the presence of all additional components, steps, or procedures.

[0009] In the following description, standards may be used. Unless otherwise specified, the version of the standard that was in effect on March 1, 2020 is used. For example, if there is no valid version on that day due to reasons such as the standard having expired, the version that was valid on the date closest to March 1, 2020 is referred to.

[0010] In the following description, the amount of a component of a composition or a polymer can be indicated by "mass percent", "wt%", or "mass%". The terms "mass percent", "wt%", or "mass%" are used interchangeably and, unless otherwise specified, are based on 100% of the total mass of the composition or polymer, respectively.

[0011] The term "phr" means parts per 100 parts of rubber, that is, mass percent based on the total amount of rubber set at 100%.

[0012] The ranges specified in this disclosure are intended to include and disclose all values between the endpoints of the range and, unless otherwise specified, include the endpoints.

[0013] Polymer : Polymers having a broad or narrow molecular weight distribution (Mw / Mn) can be produced. In one embodiment, polymers having a molecular weight distribution (Mw / Mn) of 1.80 to 30 or 2 to 10 can be produced.

[0014] Preferably, the polymer is an elastomer (also called rubber). Elastomers can be specified, among other things, by the Mooney viscosity, in contrast to thermoplastic polymers, which are usually specified by the melting point or melt viscosity. Polymers with high or low Mooney viscosities can be produced. In one embodiment, the polymer produced by this process has a Mooney viscosity ML1+4 at 125 °C of at least 20, preferably at least 40, and a Mooney viscosity ML1+8 at 150 °C of up to 100 at most. In one embodiment of the present disclosure, the polymer has a Mooney viscosity ML1+4 at 125 °C of about 40 to about 100. In another embodiment of the present disclosure, the polymer has a Mooney viscosity ML1+8 at 150 °C of about 50 to about 100.

[0015] Polymers with high or low weight average molecular weights (Mw) can be produced by a process according to the disclosure herein, but it is an advantage of the disclosure herein that high molecular weight polymers can also be produced, and high molecular weight polymers are polymers having 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 having 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, for example, about 200,000 g / mol to about 600,000 g / mol, or about 200,000 g / mol to about 500,000 g / mol.

[0016] Polymers with high or low number average molecular weights (Mn) can be produced. In one embodiment, the polymer produced by a process according to the present disclosure has a Mn of 40,000 g / mol to 250,000 g / mol. In one embodiment of the present disclosure, the polymer produced by this process 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.

[0017] Branched or chain polymers can be produced by the process according to the present disclosure. The degree of branching of the branched polymer can be high, medium, or low. The degree of branching of the polymer can be characterized by the parameter Δδ. Δδ, expressed in degrees, is the difference between the phase angle δ at a frequency of 0.1 rad / s and the phase angle δ at a frequency of 100 rad / s, and is determined by dynamic mechanical spectroscopy (DMS) at a strain of 10% at 125°C. This quantity Δδ is a measure of the amount of long-chain branching structure in the polymer and is introduced in H.C. Booij, Kautschuk + Gummi Kunststoffe, Vol. 44, No. 2, pages 128 - 130, which is hereby incorporated by reference herein. The lower the Δδ, the more branching structures are present in the polymer. In one embodiment of the present disclosure, polymers having a Δδ of 2 to 50 are produced.

[0018] The polymers produced by the process 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 a bimodal polymer or more than two peaks in the case of a multimodal polymer in the diagram 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 mixed by blending, usually wet blending, i.e., by blending the reaction mixtures.

[0019] The process according to the present disclosure is any polymerization process for producing a polymer using at least one polymerization catalyst, a solvent, and is considered applicable to any process where the reaction is exothermic. This can include the production of thermoplastic or elastomeric polymers and can include the production of rubbers, including rubbers such as EPM, EPDM, IR, BR, SBR, and HNBR. However, the process may be most useful for producing rubbers selected from the following (a), (b), and (c): (a) an ethylene / α-olefin copolymer having at least 20% by mass of units derived from ethylene, optionally further comprising units derived from at least one non-conjugated diene having 6 to 30 carbon atoms, preferably selected from dicyclopentadiene (DCPD), 5-ethylidene-2-norbornene (ENB), 5-vinyl-2-norbornene (VNB), and combinations thereof; (b) polybutadiene; and (c) a butadiene copolymer having at least 20% by mass or at least 50% by mass of units derived from butadiene. In a preferred embodiment of the present disclosure, the polymer includes an ethylene / α-olefin polymer and a butadiene polymer.

[0020] Ethylene / α-olefin polymer : In one embodiment, the polymer produced by the process according to the present disclosure is an ethylene / α-olefin polymer. The ethylene / α-olefin polymer is a copolymer of ethylene, an α-olefin, and optionally one or more additional comonomers in some cases. It is possible to produce an ethylene / α-olefin polymer that contains at least 20% by mass (based on the total mass of the polymer) of units derived from ethylene and can contain up to 80% by mass (wt%) of units derived from ethylene. In one embodiment, the ethylene-α-olefin copolymer of the present disclosure contains 40 to 70% by mass, preferably 44 to 65% by mass or 50 to 60% by mass of units derived from ethylene. These mass percentages are based on the total mass of the copolymer.

[0021] In addition to units derived from ethylene, the polymers according to the present disclosure include units derived from one or more α-olefins.

[0022] α-olefin : An α-olefin is an olefin having a single aliphatic carbon-carbon double bond. The double bond is located at the terminal (alpha position) of the olefin. The α-olefin may be aromatic or aliphatic and may be linear, branched or cyclic. Usually, the α-olefin has 3 to 20 carbon atoms.

[0023] Examples of α-olefins include those of the formula: H 2 C=X-CH 3 [wherein X represents an aliphatic alkylene residue which may be linear or branched and has 1 to 17 carbon atoms] and the like. Preferably, the branched chains independently contain 1 to 3 carbon atoms each.

[0024] In a preferred embodiment, examples of α-olefins include those of the formula: H 2 C=CH-(CH 2 ) n -CH 3 [wherein n is selected from 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, and 17] and the like.

[0025] 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.

[0026] One or more α-olefins may be used in combination. Preferably, the polymer contains at least 5 mass% or at least 10 mass% of units derived from one or more α-olefins. Polymers can be produced that contain up to 57 mass%, more preferably up to 55 mass%, of units derived from one or more α-olefins (this mass percent (wt%) is based on the total mass of the polymer). Preferably, the ethylene-α-olefin copolymer contains units derived from one or more α-olefins in a total amount of 17 to 57 mass%. Preferably, the polymer contains propylene.

[0027] Non-conjugated diene : In addition to ethylene and α-olefins, ethylene / α-olefin polymers containing units derived from one or more non-conjugated dienes as comonomers can be produced.

[0028] A non-conjugated diene is a polyene containing at least two carbon-carbon double bonds, the double bonds being non-conjugated and capable of being 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 have no substituents, the same substituents 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 having 6 to 30 carbon atoms (C 6 ~C 30 -polyenes, more preferably C 6 ~C 30Examples include non-conjugated dienes. Specific examples of non-conjugated dienes include 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-1,4-octadiene, 5-ethyl-1,4-octadiene, 5-methyl-1,5-octadiene, 6-methyl-1,5-octadiene, 5-ethyl-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, 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,Examples include, but are not limited to, 6-undecadiene, 9-methyl-1,8-undecadiene, dicyclopentadiene, and mixtures thereof. Preferred non-conjugated dienes include alicyclic polyenes. Alicyclic dienes have at least one cyclic (ring) unit. In a preferred embodiment, the non-conjugated diene is selected from polyenes having at least one internal double bond in the ring and optionally, in some cases, 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.,

[0029] Further examples of non-conjugated dienes include dual polymerizable dienes, which include α,ω-dienes, preferably linear α,ω-dienes, vinyl-substituted monocyclic and bicyclic non-conjugated dienes, which may be aromatic or aliphatic. Such dual polymerizable dienes can cause or contribute to the formation of polymer branches because both double bonds of the diene can participate in the polymerization. Examples of aliphatic dual polymerizable 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. Non-conjugated vinyl norbornene and C 8 ~C 12Alpha-omega linear dienes (e.g., 1,7-octadiene, 1,8-nonadiene, 1,9-decadiene, 1,10-undecadiene, 1,11-dodecadiene) are preferred. The diene having double bond reactivity may be further substituted with at least one group containing a heteroatom of Groups 13 to 17, such as O, S, N, P, Cl, F, I, Br, or a combination thereof.

[0030] In a preferred embodiment of the present disclosure, the diene having double bond reactivity is selected from dicyclopentadiene (DCPD), 5-vinyl-2-norbornene (VNB), 1,7-octadiene, and 1,9-decadiene, or a combination thereof, and 5-vinyl-2-norbornene (VNB) is most preferred.

[0031] Examples of the aromatic non-conjugated polyene include vinylbenzene (including its isomers) and vinylisopropenylbenzene (including its isomers).

[0032] In a typical embodiment of the present disclosure, an ethylene / α-olefin copolymer containing units derived from one or more non-conjugated dienes in an amount of at least 3% by mass and up to 15% by mass can be produced.

[0033] In another embodiment, a polymer comprising 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 units derived from VNB in an amount of 0.05% to 5% by mass, more preferably 0.10% to 3% by mass, or 0.15% to 1.2% by mass (all mass percentages are based on the total mass 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 may contain 2 to 15% by mass of units derived from ENB and 0.05 to 4% by mass of units derived from VNB.

[0034] The ethylene / α-olefin copolymer may or may not contain units derived from other comonomers and can be produced by the process according to the present disclosure. The total of the units derived from ethylene, the units derived from α-olefin, and optionally the units derived from non-conjugated diene may be more than 90% by mass, more than 99% by mass, and may also include 100% by mass, based on the total mass of the ethylene / α-olefin polymer.

[0035] Butadiene polymer : In one embodiment of the present disclosure, the polymer is a butadiene polymer. The butadiene polymer includes homopolymers and copolymers of 1,3-butadiene. Preferably, the butadiene polymer contains units derived from 1,3-butadiene of at least 20% by mass, preferably at least 50% by mass, preferably at least 60% by mass, based on the mass of the polymer. In one embodiment of the present disclosure, the diene polymer contains units derived from 1,3-butadiene of at least 60% or at least 75% by mass. The butadiene polymer may contain units derived from one or more comonomers in an amount of 0 to 49% by mass, or 0% to 40% by mass, based on the total mass of the polymer.

[0036] Suitable comonomers preferably include conjugated dienes having 5 to 24, more preferably 5 to 20 carbon atoms, but are not limited thereto.

[0037] 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.

[0038] 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, orthomethylstyrene, metaxymethylstyrene, paramethylstyrene, parat-butylstyrene, vinylnaphthalene, divinylbenzene, trivinylbenzene, divinylnaphthalene, and combinations thereof.

[0039] Suitable comonomers further include one or more α-olefins, such as ethene, propene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, and combinations thereof.

[0040] In one embodiment, the diene polymer according to the present disclosure contains 0 to 20% by mass of units derived from ethene, propene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, and combinations thereof.

[0041] Suitable comonomers also include, but are not limited to, one or more other copolymerizable comonomers that introduce a functional group containing a crosslinking site, a branching site, a branched chain, or a functionalized group. In one embodiment of the present disclosure, the diene polymer contains 0% to 10% by mass, or 0% to 5% by mass, of units derived from one or more such other comonomers.

[0042] Not only one or more combinations of the above-mentioned comonomers having the same chemical type, but also one or more combinations of comonomers having various chemical species types may be used.

[0043] Solvent : The polymerization is preferably carried out in the presence of at least one solvent. Preferably, the polymerization is carried out as solution polymerization. Preferred solvents include one or more inert hydrocarbon solvents. Suitable solvents include C hydrocarbons such as pentane, hexane, heptane, octane, cycloheptane, cyclohexane, methylcyclohexane, methylcycloheptane, pentamethylheptane, hydrogenated naphtha, their isomers and mixtures. 5~12 In another embodiment, the polymerization is carried out as slurry polymerization. When the catalyst is supported on a solid carrier that does not dissolve under the polymerization conditions, slurry polymerization can usually be used.

[0044] Chain transfer agent : 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 (H 2 ). Other chain transfer agents include, but are not limited to, ethane, diethylzinc, and combinations thereof.

[0045] Catalyst : The polymer can be produced by using one or more conventional polymerization catalysts suitable for use in the polymerization of each 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, especially titanium or vanadium.

[0046] Organometallic catalysts, especially those containing nickel, cobalt, titanium, or rare earth metals, are typically used in the production of butadiene polymers. Examples of rare earth catalysts include organometallic compounds containing neodymium, praseodymium, cerium, lanthanum, gadolinium, and dysprosium or combinations thereof.

[0047] Examples of suitable catalysts are disclosed in Canadian Patent Application No. 1,143,711A, U.S. Patent No. 4,260,707, U.S. Patent Application Publication No. 2013 / 0172489A1, or paragraphs

[0011] to

[0049] of European Patent Application Publication No. 2819853A1, all of which are incorporated herein by reference.

[0048] A metallocene catalyst is an organometallic catalyst in which a metal, typically Ti, Hf, or Zr, is bonded to at least one cyclic organic ligand, preferably at least one cyclopentadienyl-based, fluorenyl-based, or indenyl-based ligand. A catalyst in which the metal is bonded to two anionic aromatic ligands is usually referred to in the art as a "metallocene catalyst". A catalyst in which the second anionic aromatic ligand is substituted with another organic ligand is called a "half-metallocene catalyst". A metal catalyst in which both anionic ligands are substituted with organic residues is referred to in the art as a "post-metallocene catalyst". Metallocene-type catalysts include metallocenes, post-metallocene, and half-metallocene catalysts. Suitable metallocene-type polymerization catalysts are known in the art and are described, for example, in WO 2005 / 090418 A1 pamphlet, WO 2016 / 114914 A1 pamphlet, WO 2017 / 048448 pamphlet, and US Patent Application Publication No. 2015 / 0025209 A1, all of which are incorporated herein by reference.

[0049] Typically, one or more cocatalysts are added to the reaction vessel. Typical cocatalysts 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).

[0050] Suitable boron activators (C1) can be represented by the general formula BQ 1 Q 2 Q 3 and can be represented by.

[0051] Suitable borate activators (C2) can be represented by the general formula G(BQ 1 Q 2 Q 3 Q 4 Q

[0052] Suitable borate activators (C3) can be represented by the general formula (J-H)(BQ 1 Q 2 Q 3Q 4 can be represented by

[0053] In the activator according to (C1), B is boron, and Q 1 ~Q 3 is a substituted or unsubstituted aryl group, preferably a phenyl group. Suitable substituents include halogen, preferably fluorine, and C 1 ~C 40 hydrocarbyl, preferably C 1 ~C 20 alkyl or aromatic, but not limited thereto. 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(pentafluoro-phenyl)borane, and the like.

[0054] In the activator according to (C2), G is an inorganic or organic cation, B is boron, and Q 1 ~Q 3 is the same as that in (C1), and Q 4 is also a substituted or unsubstituted aryl group, preferably a substituted or unsubstituted phenyl. Substituents include halogen, preferably fluorine, and C 1 ~C 40 hydrocarbyl, preferably C 1 ~C 20 alkyl or aromatic, but not limited thereto. The borate group (BQ 1 Q 2 Q 3 Q 4Specific examples of [[ID=]] include 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, phenyltris(pentafluorophenyl)borate, tetrakis(3,5-bistrifluoromethylphenyl)borate, etc., but are not limited thereto. Specific examples of G include ferrocenium cation, alkyl-substituted ferrocenium cation, silver cation, etc. Specific examples of the organic cation G include triphenylmethyl cation, etc. G is preferably a carbenium cation, and preferably a triphenylmethyl cation.

[0055] In the activator according to (C3), J represents a neutral Lewis base, (J-H) represents a Bronsted acid, B is boron, and Q 1 ~Q 4 and the borate group (BQ 1 Q 2 Q 3 Q 4) are both the same as those in (C2). Specific examples of the Brønsted acid (J-H) include trialkyl-substituted ammonium, N,N-dialkylanilinium, dialkylammonium, triarylphosphonium, etc. Specific examples of the activator according to (C3) include triethylammonium tetrakis(pentafluoro-phenyl)borate, tripropylammonium tetrakis(pentafluorophenyl)borate, tri(n-butyl)ammonium tetrakis(pentafluorophenyl)borate, tri(n-butyl)ammonium tetrakis(3,5-bistrifluoromethylphenyl)borate, N,N-dimethyl-anilinium tetrakis(pentafluoro-phenyl)borate, N,N-diethylanilinium tetrakis(penta-fluorophenyl)borate, N,N-2,4,6-pentamethylanilinium tetrakis(pentafluorophenyl)borate, N,N-dimethylanilinium tetrakis(3,5-bistrifluoromethylphenyl)borate, diisopropyl-ammonium tetrakis(penta-fluorophenyl)borate, dicyclohexylammonium tetrakis(pentafluorophenyl)borate, triphenylphosphonium tetrakis(pentafluorophenyl)borate, tri(methylphenyl)phosphonium tetrakis(pentafluorophenyl)borate, tri(dimethylphenyl)phosphonium-tetrakis(pentafluorophenyl)borate, etc., but are not limited thereto.

[0056] Examples of other cocatalysts include, but are not limited to, alkylaluminums such as trialkylaluminum, trimethylaluminum, triethylaluminum, triisobutylaluminum, or tri-n-octylaluminum. Other examples include alkylaluminum halides such as diethylaluminum chloride, dimethylaluminum chloride, and ethylaluminum sesquichloride, and aluminoxanes such as methylaluminoxane (MAO), tetraisobutylaluminoxane (TIBAO), or hexaisobutylaluminoxane (HIBAO), but are not limited thereto. Cocatalysts are also commonly referred to in the art as "activators". The presence of a cocatalyst typically accelerates the rate at which the catalyst polymerizes olefins. The cocatalyst can also affect the molecular weight, degree of branching, comonomer content, or other properties of the polymer. Cocatalysts are typically introduced into the reactor together with the catalyst.

[0057] Scavenger : Impurities can lower the catalytic activity and potentially harm the catalyst. Compounds that react with such impurities to convert them into compounds harmless to the catalytic activity are referred to by those skilled in the polymerization art as scavengers. Scavengers can optionally be supplied to the reactor of the processes disclosed herein in some cases. Non-limiting examples of scavengers include alkylaluminum compounds such as trimethylaluminum, triethylaluminum, triisobutylaluminum, and trioctylaluminum. The scavenger can be the same compound as the cocatalyst, in which case an excess amount of the scavenger over the amount necessary to fully activate the catalyst is used. The scavenger can be introduced into the reactor separately with the monomer feed or via any other feed stream.

[0058] The scavenger can be used in combination with a sterically hindered hydrocarbon containing a heteroatom of Group 15 or 16 (preferably O, N, P, and S atoms, more preferably O and N heteroatoms), preferably a sterically hindered phenol. Specific examples of the sterically hindered hydrocarbon include, but are not limited to, tert-butanol, isopropanol, triphenylcarbinol, 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, etc.

[0059] Process : The process for producing a polymer comprises (i) supplying a monomer stream containing monomers for producing a polymer into a polymerization apparatus comprising at least one reaction vessel, wherein at least one reaction mixture containing the polymer is produced in a polymerization reaction in the presence of at least one solvent and at least one catalyst; (ii) supplying at least a part of the reaction mixture produced in the polymerization apparatus, which contains the polymer, the catalyst, and optionally monomers in some cases, into a recycle line to form a recycle stream containing the reaction mixture; (iii) lowering the temperature of the recycle stream; (iv) after the temperature of the recycle stream has dropped, supplying the recycle stream into the polymerization apparatus, the monomer stream, or both; and and the process further comprises step (v) of supplying the reaction mixture produced in the polymerization apparatus into at least one post-treatment section, preferably to remove the solvent and isolate the polymer.

[0060] The process according to the present disclosure includes recycling at least a portion of the reaction mixture generated in the polymerization reactor. The reaction mixture used for recycling is cooled before being reintroduced directly or indirectly 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 the overall energy consumption. The recycling part of the polymerization process comprises at least the following steps (ii), (iii) and (iv), and these steps can be carried out once or repeatedly, for example continuously or intermittently, preferably continuously, as steps that are carried out only once: (ii) Supplying at least a portion of the reactive reaction mixture generated in the polymerization apparatus containing the polymer to a recycle line to form a recycle stream for (re)introducing the reactive reaction mixture either into the reaction vessel of the polymerization apparatus or into the monomer stream; (iii) Lowering the temperature of the recycle stream; (iv) Introducing the recycle stream into at least one reaction vessel of the polymerization apparatus, into the monomer stream, or a combination thereof, for example by splitting the recycle stream.

[0061] The recycle stream may be introduced directly into the reaction vessel of the polymerization apparatus. Alternatively, or in addition thereto, the recycle stream may be introduced indirectly into the reaction vessel. For example, the recycle stream can be combined with the monomer stream to produce a reaction feed stream, and the recycle stream is supplied as part of the reaction feed stream to at least one reaction vessel. The recycle stream contains the reaction mixture produced in the polymerization apparatus. This reaction mixture contains a polymer and a catalyst. The reaction mixture fed to the recycle stream may contain at least 5% by weight of polymer based on the total mass of the reaction mixture. In one embodiment of the present disclosure, the reaction mixture fed to the recycle stream contains 5% to 15% by weight of polymer. The reaction mixture in the recycle stream may optionally contain monomers in some cases, and may optionally contain solvents in some cases. The reaction mixture in the recycle stream contains a catalyst and is still reactive. 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, the polymerization reaction can be suppressed or its reaction rate can be decreased, but the polymerization reaction can continue in the recycle stream.

[0062] Next, the process according to the present disclosure will be described in more detail with reference to FIG. 1 for illustration.

[0063] A monomer stream (1) containing monomers for producing an ethylene / α-olefin copolymer is generated. The monomer stream (1) is preferably a single stream and preferably contains all the various 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. The monomer and the solvent are fed together into the polymerization (4) apparatus in one feed stream. 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 the unused 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 includes temperatures from -30°C to +39°C, or higher than -25°C and up to a maximum of +39°C. Preferably, T1 is from -15°C to a maximum of +25°C, or from -10°C to +20°C. Preferably, the monomer stream is pressurized to maintain the monomer in a liquid state and / or dissolve the monomer in the solvent.

[0064] The monomer feed stream (1) is introduced into the polymerization apparatus (4). The polymerization apparatus is a section of the process in which the polymer is produced. The polymerization apparatus may include one or more reaction vessels, and in each of the reaction vessels, a polymerization reaction can be carried out. When multiple reaction vessels are used, the vessels can be connected in series, in parallel, or a combination thereof. The reaction vessel has at least one device for mixing the contents of the reactor or at least a part of the contents of the reactor. Typical reaction vessels include stirred tank reactors, preferably continuous stirred tank reactors (CSTRs), which means that the contents of the reactor are continuously stirred during the polymerization reaction. Such reactors are known in the art. Typically, a stirred tank reactor is a pressure reaction vessel including one or more rotating agitators and / or preferably one or more impellers on a central agitator shaft, which is used to mix the contents of the reactor. Examples of impellers include, but are not limited to, INTERMIG, VISCOPROP, and VARIOBLADE from Ekato Systems GmbH. Typically, one or more baffles are often installed on the wall of the reactor to improve the quality of stirring. However, other types of reaction vessels having mixing elements suitable for solution or slurry polymerization, other than stirred tank reactors, can also be used. The process can be used on a small scale or an industrial scale, and it is preferred that at least one reactor having a reactor volume of more than 3 liters, for example, having a volume of about 4 to 4000 liters, is used. It is preferred that the polymerization apparatus has at least one reactor having a reactor volume of about 4 to 4000 liters and the process is carried out on an industrial scale where the process is carried out continuously. Usually, reaction raw materials are introduced into at least one reaction vessel by one or more feed streams (1), and the effluent of the reactor is recovered using the outlet stream (5). Typically, the feeds of chain transfer agents, solvents, catalysts, and monomers are introduced at one or more points within the reaction vessel using various types of feed injectors. Usually, one or more catalyst components are introduced separately from the monomers in a similar manner via one or more catalyst injectors.The chain transfer agent and the solvent can be introduced separately from the monomer stream, but it is preferably added to the monomer stream in advance and introduced into the reactor as a component of the monomer stream. The scavenger is preferably introduced via the monomer stream (1). In the case of connected reaction vessels, the reaction mixture from one reaction vessel can be fed to another reaction vessel in place of or in addition to a fresh monomer stream.

[0065] Mixers are frequently used downstream of each feed or catalyst injector to improve the mixing of these feed streams into the bulk fluid.

[0066] The reactor is jacketed and can add or remove heat. The reactor may include a cooling coil to assist in removing the heat of polymerization. Preferably, the reactor is operated adiabatically. When the reactor is operated adiabatically, little or no heat removal or addition by internal or external heating or cooling devices is performed. For example, less than 20%, less than 10%, or even 0% of the temperature inside the reactor is caused (or removed, or both) by external or internal heating or cooling devices. Instead, the temperature inside the reactor is completely or mainly controlled by the exothermic reaction, the temperature and flow of the reaction raw materials and the effluent, the temperature and flow rate of the reactant stream entering the reactor, the residence time inside the reactor, and the temperature and flow rate of the effluent exiting the reactor, or a combination thereof. Typically, the condensation of the gas phase occurring inside the reactor is not used to remove heat from the reaction vessel. Preferably, the reactor is operated to avoid the formation of condensable monomer gas, i.e., the monomer is kept dissolved in the solvent or in the liquid state. For example, the reactor can contain a sufficient amount of solvent and can be operated under sufficient pressure to avoid the formation of monomer gas. For example, the reactor is filled with solvent or generally liquid at least 50%, or at least 75%, preferably at least 90% or even 95% based on the available reactor volume, and contains components such as reactants, solvents, and reaction products in dissolved, suspended, or dispersed forms in the liquid. Preferably, the polymerization apparatus and the recirculation line are operated under sufficient pressure so that the (unused and new) monomer is kept dissolved in the solvent or in the liquid state, or both. In one embodiment of the present disclosure, the solvent is likewise kept in the liquid state inside the reactor.

[0067] In the process according to the present disclosure, the polymerization apparatus (4) preferably includes at least one reaction vessel operated as a stirred tank reactor. Typically, a temperature T4 of about 50 °C to 160 °C, or 60 °C to 120 °C, can be achieved in at least one reaction vessel of the polymerization apparatus during polymerization. The temperature is adapted to the polymerization rate and the polymer to be produced and may vary depending on the reaction system used. However, the process is carried out such that the temperature in the reaction vessel in which the polymerization is carried out is lower than the temperature at which the catalyst used in the polymerization is deactivated.

[0068] The residence time of the reactants in the polymerization apparatus (4) is adapted to produce a reaction mixture containing the desired polymer in the desired amount. In addition to the polymer, the reaction mixture may contain a solvent and, likewise, may contain unreacted monomers and optionally in some cases a chain transfer agent, a catalyst, and further components.

[0069] The outlet stream (5) (also referred to herein as the "product stream") removes the effluent of the reactor containing the reaction mixture obtained by the polymerization reaction. The reaction mixture may be fed to the next reactor for further polymerization with or without addition of unreacted monomer and / or with or without addition of an unused or different catalyst, or may be sent directly to at least one post-treatment section (6) without passing through other reactors, where the polymer is isolated from the reaction mixture. The post-treatment section (6) may include a devolatilization section for removing the solvent, for example, by one or more strippers. The post-treatment unit may include one or more vessels, pumps, and mixers for post-treating the polymer or for mixing with additional components such as extender oils or other additives. The solvent and unreacted monomers can be recycled and reused in the polymerization process. Before entering the post-treatment section (6) or during the post-treatment section (6), the catalyst contained in the outlet stream (5) is a polar component such as water, alcohol, acid, ester, O 2 、CO、CO 2It can be deactivated by adding, or any component known to react with the catalyst to stop the polymerization. If the oil-extended polymer is to be produced as known in the art, one or more extender oils may be added to the reaction mixture before removing the solvent. Suitable extender oils include petroleum oils such as aromatic oils and naphthenic oils; polyalkylbenzene oils; monoesters of organic acids such as alkyl and alkoxyalkyl oleates and stearates, diesters of organic acids such as dialkyl, dialkoxyalkyl and alkylaryl phthalates, terephthalates, sebacates, adipates and glutarates; glycol diesters such as tri-ethylene glycol dialcanoates, tetra-ethylene glycol dialcanoates, and polyethylene glycol dialcanoates; trialkyl trimellitates; trialkyl, trialkoxyalkyl, alkyldiaryl and triaryl phosphates; chlorinated paraffin oils; coumarone indene resins; rosin; vegetable oils such as castor oil, tall oil, rapeseed oil and soybean oil, and their esters and epoxidized derivatives, etc., but are not limited thereto.

[0070] At least a portion of the reaction mixture produced in the polymerization apparatus (4) is supplied as a recycle stream (2) to at least one recycle line. For example, 1% to 95%, or 10% to 50% (volume percentage based on the total volume of the reaction mixture) of the reaction mixture is used for recycling. A portion of the reaction mixture used for recycling can be taken directly from the reactor or as shown in FIG. 1, or can be taken from the product stream (5) before adding an additive that deactivates / inactivates the catalyst to the product stream. In one embodiment, the recycle stream (2) is taken 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 utilized for the recycle stream. In one embodiment of the present disclosure, the recycling process is carried out intermittently, and 100% of the product stream is used for at least one recycle cycle. The recycle stream (2) is supplied to a cooling unit in at least one recycle line and subsequently supplied to a monomer stream or a reaction vessel, or a combination thereof. The recycle line can include one or more pumps for sending the recycle stream (2) through the recycle line. Pumps known in the art for transporting polymerization reaction mixtures can be used. Transfer (sending forward) can similarly or additionally be achieved by using a pressure difference or other means known in the art. The recycle line typically has a diameter smaller than the diameter of the reaction vessel. The total volume of the recycle line can be smaller than, larger than, or the same as the volume of the reactor of at least one reaction vessel.

[0071] The reaction mixture may be removed from the reactor and / or the product line for continuous or discontinuous recycling. For example, the reaction mixture may be subjected to recycling only at specific time intervals. The product stream can be supplied to the post-treatment section (6) continuously or discontinuously. For example, the product stream to the post-treatment section (6) may be interrupted at time intervals and instead used for recycling. Preferably, the process is carried out continuously and both the product stream (5) and the recycle stream (2) are operated continuously.

[0072] In one embodiment of the process according to the present disclosure, steps (ii) to (iv) are carried out one or more times before subjecting the reaction mixture produced in the polymerization apparatus to post-treatment in order to remove the solvent and isolate the polymer. This can be carried out in either a batch process or a continuous process. In one embodiment of the present disclosure, the recirculation steps (ii) to (iv) may be carried out, for example, in a continuous process simultaneously with step (v) which comprises feeding the reaction mixture produced in the polymerization apparatus to at least one post-treatment unit in order to remove the solvent and isolate the polymer. In one embodiment of the process according to the present disclosure, the recirculation steps (ii), (iii) and (iv) are carried out at least once or a plurality of times before step (v) is carried out.

[0073] Before the recycle stream is introduced directly or indirectly into the polymerization apparatus for addition to the polymerization reaction, the temperature of the recycle stream (2) is lowered in the cooling unit (8). In the cooling unit (8), the temperature of the recycle stream (2) can be lowered using one or more coolers. Preferably, the cooling unit (8) includes at least one heat exchanger. A single heat exchanger or multiple heat exchangers connected in series or in parallel can be used. Instead of or in addition to the heat exchanger, one or more other devices for lowering the temperature may be used, but a heat exchanger is preferred. Before its temperature is lowered, the recycle stream (2) can have approximately the same temperature as the reaction vessel from which it is derived. 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 lowered to temperature T2. Typically, the temperature T2 of the recycle stream (2) is lower than the temperature of the reaction vessel of the polymerization apparatus into which the recycle stream (2) is fed. The temperature T2 can be the same as the temperature T1 of the monomer stream (1), or the temperature T2 can be higher than the temperature T1, or the temperature T2 can be lower than the temperature T1. Examples of the 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 lowered to a temperature T2 of 20 °C to 85 °C. After the temperature of the recycle stream (2) has been cooled to temperature T2, the recycle stream (2) is introduced directly or indirectly into the polymerization apparatus. This can be carried out in different ways. In the embodiment shown in FIG. 1, the recycle stream is combined with the monomer stream (1) to produce a reactant stream (3). The recycle stream is then introduced indirectly as part of the reactant stream (3) into at least one reaction vessel of the polymerization apparatus (4) to produce a polymer. Instead of or in addition to this, the recycle stream (2) can be fed directly into the reaction vessel of the polymerization apparatus (4) to produce a polymer without being combined with the monomer stream (1).

[0074] In the embodiment shown in FIG. 1, the recirculation stream (2) is combined with the monomer stream after its temperature has dropped to temperature T2 and before the recirculation stream (2) is fed as a reactant stream together with the monomer stream into the reaction vessel of the polymerization apparatus (4). In this embodiment of the present disclosure, the temperature of the recirculation stream (2) may be lowered to a temperature (T2) about 20 °C to 80 °C lower than the temperature at which the reaction vessel for feeding the reaction raw material stream is operated before the recirculation stream (2) is combined with the monomer stream (1). The temperature T2 in this embodiment is higher than the temperature (T1) of the monomer stream (1). Typically, the monomer stream of the process according to the present disclosure may have a temperature T1 that is higher than -25 °C and up to a maximum of +39 °C. In one embodiment of the present disclosure, the monomer stream has a temperature T1 from -15 °C to a maximum of +25 °C, or from -10 °C to +20 °C. In one embodiment of the present disclosure, the temperature of the recirculation stream (2) is lowered to a temperature (T2) of about 20 °C to 80 °C at which the recirculation stream (2) is combined with the monomer stream (1), or directly introduced into the vessel of the reactor, or both, where the temperature of the monomer stream (T1) is higher than -25 °C and up to a maximum of +39 °C, and T1 is preferably from -15 °C to a maximum of +25 °C, or from -10 °C to +20 °C.

[0075] In the embodiment shown in FIG. 1, the recycle stream (2) is combined with the monomer stream (1). By mixing the monomer and the recycle stream, the resulting reaction feed stream (3) can reach a temperature T3 before entering the reaction vessel of the polymerization apparatus (4). Typically, the temperature T3 of the reaction feed stream (3) is higher than the temperature T of the monomer stream (1). Typically, the temperature T3 is lower than the temperature of the recycle stream (T2) when combined with the monomer stream (1), and typically, T3 is lower than the temperature at which the reaction vessel to which the reactant stream (3) is supplied is operated. The temperature T3 may be, for example, from 10°C to 90°C. The temperature of the reaction feed stream (T3) can be adjusted by means 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 feed stream (3) can be increased or decreased by external means such as, for example, a heat exchanger, a heating unit, or a cooling unit, although this may not necessarily be required and may not be desirable due to additional energy costs.

[0076] The recirculation stream (2) may contain a polymer, unreacted monomers, a catalyst, and an activator and may be reactive. The polymerization reaction can continue within the recirculation stream (2). The recirculation stream can contain, for example, 5 to 15% by weight of polymer, 1% to 10% by weight or 2% to 20% by weight of polymer, based on the total mass of the recirculation stream. However, since the recirculation stream is reintroduced into the polymerization apparatus, while it is acceptable or desirable to continue polymerization in the recirculation stream, polymerization in the recirculation line, specifically clogging in the cooling unit and fouling of the reactor can result, so polymerization in the recirculation line is preferably suppressed, reduced, or decelerated. This can be achieved by various measures that can be implemented alone or in combination. It is preferred not to add additional catalyst, activator, or both to the recirculation stream (2) until at least the recirculation stream (2) passes through the cooling unit (8). Preferably, the residence time of the recirculation stream (2) is shorter than the residence time in the polymerization apparatus (4). The residence time of the recirculation stream (2) can be, for example, 1.5 to 150 times shorter, i.e., 1 / 150 to 2 / 3, of the residence time of the polymerization apparatus (4). The residence time of the recirculation stream (2) is measured between the point where the reaction mixture is withdrawn and fed to the recirculation line for recirculation and the point where the recirculation stream is introduced into the reaction vessel of the polymerization apparatus or the point where the recirculation stream is combined with the monomer stream. The residence time of the polymerization apparatus is measured from the time the monomer stream enters the first reaction vessel of the polymerization apparatus until the final polymer exits the reaction vessel. The residence time can be calculated or experimentally measured by methods known in the art. Preferably, the flow rate (flow velocity) of the recirculation 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 recirculation stream (2) is at least 1.5 times faster than the monomer stream (1), for example 1.5 to 15 times faster. The recirculation line may include one or more pumps for controlling or regulating the flow rate of the recirculation stream (2). Alternatively or in addition thereto, one or more chain transfer agents (CTAs) can be added to the recirculation stream (2) to reduce or completely suppress the formation of long polymer chains.Preferably, the additional chain transfer agent is fed into the recirculation stream (2) by an optional CTA feed stream (7) as shown in FIG. 1. Preferably, the chain transfer agent (CTA) is added to the recirculation stream (2) before or during cooling of the recirculation stream (2) in the cooling section (8). The chain transfer agent added to the feed stream (7) may be the same as the chain transfer agent that can be added to the monomer stream (1), or it may be a different CTA. When the chain transfer agent is added to the recirculation stream, the chain transfer agent may be introduced into the polymerization apparatus (4) together with the recirculation stream (2) or the reactant stream (3). Therefore, when adding the chain transfer agent to the recirculation stream, the total amount of CTA in the recirculation stream must be taken into account, and it is necessary to adjust the new addition of CTA to the monomer stream (1) or to the reaction unit (4), for example, to reduce or interrupt it.

[0077] In a process in which reaction vessels are connected in series, the reaction mixture containing the first polymer produced in the vessel of the first reactor is fed to at least the second reaction vessel to produce at least a second reaction mixture containing the second polymer. The volumes of these vessels may be the same or different. The residence times in these vessels may likewise be the same or different. The mixers in these vessels may be the same or different, and the mixing rates may be the same or different. For the recirculating part of the process, the first reaction mixture or at least the second reaction mixture, or both, can be used. Such a process enables the production of, for example, unimodal polymers and, for example, multimodal polymers when the catalysts used in the first and second reaction vessels are different. Embodiments of the process according to the present disclosure having reactors connected in series are shown in FIGS. 2 and 3.

[0078] The process shown in Figure 2 is in principle the same as the process shown in Figure 1, except that the polymerization apparatus (4) includes a first reaction vessel (4a) and a second reaction vessel (4b). The effluent (5a) containing the first reaction mixture containing the polymer produced in the first reaction vessel (4a) is fed into the second reaction vessel (4b) for further polymerization. In one embodiment of the present disclosure, one of the following is added to the second reaction vessel (4b): the reaction mixture obtained in the first reaction vessel, unreacted monomer, unreacted solvent, catalyst, and optional components or combinations thereof. In another embodiment of the present disclosure, only the effluent of the first reaction vessel (4a) is fed into the second reaction vessel, and the polymerization continues in the second vessel. The effluent (5b) of the second reaction vessel contains the final polymer and is fed into the post-treatment unit (6). Instead of the two reaction vessels shown in Figure 2, three or more reaction vessels may be connected in the same way. A part of the effluent (5b) is led through a cooling unit (8) into the monomer stream (1) by the flow (2) of the recirculation line, and is combined with it to form a reaction feed stream (3), and the reaction feed stream (3) is introduced into the first reactor (4a) for further polymer production. The chain transfer agent may be added to the recirculation stream (2) via the CTA feed stream (7) before or during the recirculation stream (2) entering the cooling unit (8). As shown in Figure 2, instead of feeding the recirculation stream (2) into the monomer stream (1), the recirculation stream (2) may instead or in addition be fed directly into the first reactor (4a), or into the effluent (5a), or directly introduced into the second reactor vessel (4b). Instead or in addition, the recirculation stream (2) can be directly fed into one or both of the reaction vessels, for example the reaction vessel (4a) or the reaction vessel (4b), without being combined with the monomer stream (1). The recirculation stream (2) can be fed continuously or intermittently into (4a) and (4b) for a while. Instead of or in addition to taking out the recirculation stream (2) from the effluent (5b), the recirculation stream (2) may be taken out from the effluent (5a) or both. In another embodiment, two separate recirculation streams are generated, one from the effluent (5a) and the other from the effluent (5b).They may be supplied by separate recycle lines or may be combined in a single recycle line and introduced into vessel (4a), into vessel (4b), or into both vessels or into the monomer stream, or one of the recycle streams may be combined with the monomer feed stream (1) and the other may be fed directly to the reaction vessel.

[0079] Figure 3 shows an embodiment of the process according to the present disclosure in which the recycle stream (2) is withdrawn from the effluent (5a) of the first reaction vessel (4a) before entering the second reaction vessel (4b).

[0080] Instead of using reaction vessels in series, the reaction vessels of the polymerization apparatus (4) may be arranged in parallel. The effluents of the reactors may be combined, for example, in a mixer or in another reactor, before or during the removal of the solvent and the work-up of the polymer. Such an arrangement enables the production of, for example, multimodal polymers or polymer blends, such as "reactor blends", i.e., polymer blends obtained by wet mixing.

[0081] The recycle stream (2) can be made using the reaction mixture of one or more or all of the reaction vessels, or from the combined effluent, before entering the devolatilization section and before the catalyst is deactivated. The recycle stream can be directed to one or all of the reaction vessels. One embodiment of such a parallel reactor process is shown in FIG. 4 to which reference is made herein. The first part of the process is in principle identical to the process shown in FIG. 1, however, a second monomer feed (1') is introduced into a second polymerization unit (4') to produce a product stream (5'). The product stream (5') is combined with the product stream (5) from the first polymerization unit (4) and sent to a post-treatment section (6). The reaction mixture from the effluent is used for recycling before the product stream (5) is combined with the product stream (5'). The process shown in FIG. 4 uses only one recycle stream for the first polymerization unit. In one embodiment of the present process, both polymerization units (4) and (4') can have their own recycle streams (2) and (2') respectively withdrawn from the effluents (5) and (5'). As described above, the recycle stream may be directly fed to one or more reaction vessels of the polymerization unit (4) or (4') or both polymerization units, after being combined with the monomer feed (1) or (1'), or without being combined.

Example

[0082] The present disclosure will be further illustrated by examples without any intention to limit the disclosure to the specific examples presented herein.

[0083] Test method: <Polymer composition>: The composition of the copolymer was determined using Fourier transform infrared spectroscopy (FT-IR) in accordance with ASTM D3900 (revision date 2017) for the C2 / C3 ratio on a pressed polymer film and in accordance with D6047 (revision date 2017) for the diene content.

[0084] <Measurement of phase angle>: The branching of the polymer was determined by measuring the phase angle with a Montech MDR3000 moving dielectrometer for the parameter Δδ. 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, which was 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 longer the chain branches present in the polymer, which was introduced by H.C. Booij in Kautschuk + Gummi Kunststoffe, Vol. 44, No. 2, pages 128 - 130, 1991, which is hereby incorporated by reference into this specification.

[0085] <Molecular weight>: The molecular weights (Mw, Mn, Mz) and molecular weight distribution (MWD) can be determined by gel permeation size exclusion chromatography (GPC) using PolymerChar GPC-IR from Polymer Characterization S.A Valencia, Spain. This size exclusion chromatography is equipped with an on-line viscometer (Polymer Char V-400 viscometer), an on-line infrared detector (IR5 MCT), three AGILENT PL OLEXIS columns (7.5 x 300 mm), and a Polymer Char autosampler. The universal calibration of the system is performed using a polyethylene (PE) standard sample.

[0086] The polymer sample is weighed in a vial of the PolymerChar autosampler (in the concentration range of 0.3 - 1.3 mg / ml). In the autosampler, the vial is automatically filled with a solvent (1,2,4-trichlorobenzene stabilized with 1 g / l of di-tert-butylparacresol (DBPC)). The sample is held in a high-temperature oven (160°C) for 4 hours. After this dissolution time, the sample is automatically filtered through an in-line filter before being injected into the column. The chromatography system is operated at 160°C. The flow rate of the 1,2,4-trichlorobenzene eluent is 1.0 mL / min.

[0087] <Mooney viscosity>: The Mooney viscosity of the copolymer sample was measured in accordance with ISO 289, revision date 2015, using a biaxially strained PP (thickness 20 μm) film provided by Perfon B.V., Goor, The Netherlands. The measurement conditions were ML(1+4) at 125 °C.

[0088] <Polymerization>: The polymerization for producing the EPDM polymer was 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 test setup consisted of two liquid-filled stirred tank reactors for solution polymerization connected in series, and was essentially as shown in Figure 2. Both reactors (4a) and (4b) had a volume of 3 liters. This setup was used as a demonstration of a principle experiment. Since it has been found that the reactor volume is not critical, it is considered that this process can be carried out in large reactors having a reactor volume exceeding 3 liters, for example, reactors having a volume of 4 to 4000 liters. The monomer and the solvent were fed together in one line (monomer stream (1)) to the first reactor (4a). The catalyst and the activator were fed to the first reactor (4a) in separate lines. The effluent (5a) from the first reactor (4a) was fed to the second reactor (4b), and no other feeds other than this effluent were introduced into the second reactor (4b). The discharge line (5b) fed a part of the reactor effluent of the second reactor to the post-treatment unit (6) and the remaining part to the recycle line (2). The recycle line (2) was pumped through the heat exchanger of the cooling unit (8) to lower its temperature. Next, the recycle line (2) was merged with the feed line (1) to generate a reaction feed stream (3), which entered the first reactor (4a) of the polymerization unit (4). Hydrogen was added to the feed line (1) as a chain transfer agent. The amount of hydrogen was adjusted to achieve the Mooney viscosity of the desired polymer as shown in Table 1. Different from the drawing in Figure 2, no chain transfer agent (7) was added to the recycle stream.

[0089] The feed stream was purified by contacting it with various absorption media to remove impurities that deactivate the catalyst, such as water, oxygen, and polar compounds. The process was carried out continuously for all feed streams. The premixed solvent (a mixture of hexane isomers with a boiling range of 65°C to 70°C), propene, ethylene, ENB, and VNB, hydrogen, and scavenger were precooled before being fed to the reactor. The solution containing the catalyst and the solution containing the activator were fed to the reactor separately. The feed rate of the solvent was 29.1 liters / h, the feed rate of ethylene was 30.2 moles / h, the feed of propylene was 27.1 moles / h, and the feed of ENB was 966 millimoles / h. The pressure was 20 barg. Polymerization was initiated by introducing the catalyst and activator into the system. The recycle flow rate was set to twice the feed rate. The feed rate is the sum of the mass flow rates of the monomer and the solvent.

[0090] The polymer solution (reaction mixture) was continuously withdrawn from the second reactor via the discharge line (5b), a part of the reaction mixture was fed to the recycle line (2), and the remaining reaction mixture was fed to a post-treatment vessel. An isopropanol solution of IRGANOX 1076 was added in the post-treatment vessel to stop further polymerization and stabilize the polymer. Residual monomers and solvents were removed by continuous steam stripping to obtain a polymer mass. The obtained EPDM polymer was dried batchwise in a mill. The composition of the EPDM polymer obtained by this process and further processing conditions are shown in Table 1.

[0091]

Table 1

[0092] In Table 1, "Prod" means the polymer production rate in grams per hour, and "C2" means the unit derived from ethylene. The remaining EPDM polymer (other than the units derived from C2, ENB, and VNB) is composed of units derived from propylene.

[0093] As shown above, an EPDM polymer having a weight average molecular weight greater than 200,000 g / mol was produced using a monomer / solvent feed stream that only needed to be cooled to 10 °C, and thus only moderate cooling of the monomer and solvent was required.

Claims

1. A method for producing a polymer, comprising: (i) supplying a monomer stream containing monomers for producing the polymer into a polymerization apparatus including at least one reaction vessel, wherein at least one reaction mixture containing the polymer is produced by a polymerization reaction in the presence of at least one solvent and at least one catalyst; (ii) supplying at least a part of the reaction mixture produced in the polymerization apparatus, which contains the polymer, the catalyst and / or does not contain the monomer, into a recirculation line to form a recirculation stream; (iii) lowering the temperature of the recirculation stream; (iv) after the temperature of the recirculation stream has dropped, supplying the recirculation stream into the polymerization apparatus, the monomer stream or both; and the polymer is an elastomer selected from (a) an ethylene / α-olefin copolymer having at least 20% by mass of ethylene-derived units, which may or may not further contain units derived from at least one non-conjugated diene having 6 to 30 carbon atoms, (b) polybutadiene, and (c) a butadiene copolymer having at least 50% by mass of butadiene-derived units.

2. The method according to claim 1, comprising continuously or intermittently repeating steps (ii) to (iv).

3. The method according to claim 1, wherein steps (ii) to (iv) are carried out one or more times before subjecting the reaction mixture produced in the polymerization apparatus to post-treatment in order to remove the solvent and isolate the polymer.

4. The method according to claim 1, wherein the flow rate of the recirculation stream is faster than the flow rate of the monomer stream.

5. The residence time of the recirculation stream, determined from the time when the reaction mixture is supplied into the recirculation line to form the recirculation stream until the time when the recirculation stream enters either the monomer stream or the reaction vessel, is shorter than the residence time of the polymerization apparatus, determined from the time when the monomer stream enters the reaction vessel until the time when the effluent of the reaction vessel exits the reaction vessel for post-treatment of the polymer.

6. The method according to claim 1, wherein the temperature of the recirculation stream is lowered in a cooling unit including at least one heat exchanger.

7. The method according to claim 1, wherein the temperature of the recirculation stream is lowered in the cooling unit, and no additional catalyst or activator or both are added to the recirculation stream before the recirculation stream passes through the cooling unit.

8. The method according to claim 1, wherein after the temperature of the recirculation stream is lowered, the temperature of the monomer stream is lower than the temperature of the recirculation stream, the temperature of the monomer stream is higher than -25 °C and up to a maximum of 39 °C.

9. The method according to claim 1, wherein the temperature of the at least one stirred tank reactor during the polymerization reaction is from 60 °C to 120 °C.

10. The method according to claim 1, wherein the monomer stream comprises a monomer and a solvent.

11. The polymerization apparatus comprises at least a first reaction vessel and at least a second reaction vessel, the reactors can be connected in series or in parallel, a first reaction mixture is produced in the first reaction vessel in a polymerization reaction in the presence of at least one solvent and at least one catalyst, and a second reaction mixture is produced in the second reaction vessel in a polymerization reaction in the presence of a solvent and at least one second catalyst, and the recirculation stream comprises at least a part of the first reaction mixture or at least the second reaction mixture or both, and the first polymerization catalyst is the same or different from the second polymerization catalyst. The method according to claim 1.

12. The method according to claim 1, comprising adding a chain transfer agent to the recirculation stream, wherein the addition of the chain transfer agent is continuous, intermittent or a single addition.

13. The method according to claim 1, wherein at least the at least one reaction vessel is pressurized to keep the monomer in a dissolved or liquid state.

14. The method according to claim 1, wherein the polymer is an ethylene / α-olefin copolymer containing units derived from ethylene and propylene.

15. The method according to any one of claims 1 to 14, wherein the polymerization reaction is carried out as slurry polymerization or solution polymerization.

Images