# US 9,040,644 B2 · Process for preparing a diene elastomer, such as a polybutadiene > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,040,644 B2 - Document ID: US9040644B2 - Status: Granted - Kind: B2 - Application number: 11/922,097 - Filed: 2006-04-06 - Published: 2010-02-18 - Granted: 2015-05-26 - Earliest claimed: 2005-06-14 - Assignees: Compagnie Generale Des Etablissements Michelin; Michelin Recherche et Technique S.A. - Applicants: Clotilde Canivet; Jean-Philippe Rasigade; Fanny Barbotin - Inventors: Clotilde Canivet; Jean-Philippe Rasigade; Fanny Barbotin - Web page: https://patentgrep.com/patent/US9040644B2 ## CPC - C08F 136/06: Butadiene - C08F 136/08: Isoprene - C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS ## Abstract The present invention relates to a process for preparing a diene elastomer. The invention especially applies to the production of a polybutadiene with a high level of cis-1,4 linkages that has at the same time a Mooney viscosity ML (1+4) greater than or equal to 40, a polydispersity index less than 2.1 and a reduced cold flow and of a polyisoprene. The process according to the invention comprises a reaction of a catalyst system with at least one conjugated diene monomer, this catalyst system being based on at least: one conjugated diene; one organic phosphoric acid salt of one or more rare-earth metals, said salt being in suspension and in at least one saturated and aliphatic or alicyclic, and inert hydrocarbon-based solvent; one alkylating agent composed of an alkyl aluminum for formula AlR3 or HAlR2 and a halogen donor belonging to the family of alkylaluminium halides, with the exclusion of alkylaluminium sesquihalides. This process comprises a separate bringing together of the monomer(s) to be polymerized with at least one alkylaluminium compound of formula AlR3 or HAlR2 which is identical or not to the alkylating agent of said catalyst system, said amount being chosen as a function of the characteristics of the polymerization medium and/or the polymerization conditions and/or said elastomer to be obtained. ## Claims ### Claim 1 Process for preparing a diene elastomer, comprising a continuous or batch polymerization reaction, in solution or in bulk, of at least one conjugated diene monomer with a catalyst system, said catalyst system being based on at least: one preforming conjugated diene monomer; one organic phosphoric acid salt of one or more rare-earth metals, said salt being in suspension and in at least one saturated, aliphatic or alicyclic, inert hydrocarbon-based solvent; one alkylating agent composed of an alkyl aluminium of formula AlR3 or HAlR2 in which R represents an alkyl radical and H a hydrogen atom; and a halogen donor belonging to the family of alkylaluminium halides, with the exclusion of alkylaluminium sesquihalides, wherein at least one alkylaluminium compound of formula AlR3 or HAlR2 in which R represents an alkyl radical and H represents a hydrogen atom, which is identical or not to that of said catalyst system, is separately introduced at a time different from the time of introduction of the catalyst system, into an industrial polymerization unit; and wherein the separately introduced alkylaluminium compound and the alkylating agent are present in a molar ratio that varies from 0.05 to 3. ### Claim 2 (depends on 1) Process according to claim 1, wherein all of the separately introduced alkylaluminium compound(s) of formula AlR3 or HAlR2 wherein R and H have the same meanings as in claim 1 added is introduced into the industrial polymerization unit before the introduction of the catalyst system. ### Claim 3 (depends on 1) Process according to claim 1 wherein prior to the polymerization reaction, the separately introduced alkyaluminium compound of formula AlR3 or HAlR2, wherein R and H have the same meanings as in claim 1 is brought together with the conjugated diene monomer(s) to be polymerized. ### Claim 4 (depends on 1) Process according to claim 1 wherein prior to the polymerization reaction, the separately introduced alkyaluminium compound of formula AlR3 or HAlR2, wherein R and H having the same meanings as in claim 1 is brought together with the conjugated diene monomer(s) to be polymerized and the polymerization solvent. ### Claim 5 (depends on 1) Process according to claim 1, wherein the alkylating agent/salt of rare-earth element(s) molar ratio in said catalyst system has a value ranging from 1 to 10. ### Claim 6 (depends on 1) Process according to claim 1, wherein the amount of said separately introduced alkylaluminium compound brought together with said conjugated diene monomer(s) to be polymerized varies from 10 to 5,000 μmol per 100 g of conjugated diene monomer(s) to be polymerized. ### Claim 7 (depends on 6) Process according to claim 6, wherein said separately introduced alkylaluminium compound is used in an amount ranging from 50 to 1,000 μmol per 100 g of conjugated diene monomer(s) to be polymerized, then said catalyst system is used in an alkylating agent/salt of rare-earth element(s) molar ratio ranging from 1 to 5. ### Claim 8 (depends on 1) Process according to claim 1, wherein said reaction is carried out continuously, said separately introduced alkylaluminium compound being brought together with said conjugated diene monomers) to be polymerized in a line inlet located upstream of at least one polymerization reactor. ### Claim 9 (depends on 8) Process according to claim 8, wherein said catalyst system is incorporated in its entirety in the industrial polymerization unit, in said line inlet. ### Claim 10 (depends on 8) Process according to claim 8, wherein said catalyst system is incorporated in its entirety in the industrial polymerization unit directly in said reactor. ### Claim 11 (depends on 1) Process according to claim 1, wherein said reaction is carried out in an inert hydrocarbon-based polymerization solvent or else in bulk. ### Claim 12 (depends on 1) Process according to claim 1, wherein said separately introduced alkylaluminium compound is diisobutylaluminium hydride. ### Claim 13 (depends on 1) Process according to claim 1, wherein said halogen donor is an alkylaluminium monohalide. ### Claim 14 (depends on 1) Process according to claim 1, wherein said salt is a tris[bis(2-ethylhexyl)phosphate] of rare-earth element(s). ### Claim 15 (depends on 1) Process according to claim 1, wherein said alkylating agent comprises diisobutylaluminium hydride. ### Claim 16 (depends on 1) Process according to claim 1, wherein said catalyst system comprises said rare-earth metal or metals in a concentration greater than or equal to 0.002 mol/l. ### Claim 17 (depends on 1) Process according to claim 1, wherein the halogen donor/salt molar ratio has a value ranging from 2 to 3.5. ### Claim 18 (depends on 1) Process according to claim 1, wherein the preforming conjugated diene monomer/salt molar ratio has a value ranging from 15 to 70. ### Claim 19 (depends on 1) Process according to claim 1, wherein said conjugated diene monomer to be polymerized is butadiene, in order to obtain a butadiene homopolymer having at the same time: a Mooney viscosity ML(1+4) at 100° C., measured according to the standard ASTM D 1646, which is greater than or equal to 40; a polydispersity index less than 2.1; a level of cis-1,4 linkages greater than 90%; and a reduced cold flow ranging from 0.01 g to 0.5 g. ### Claim 20 (depends on 1) Process according to claim 1, wherein said conjugated diene monomer to be polymerized is butadiene, in order to obtain a butadiene homopolymer having a cold flow ranging from 0.01 g to 0.3 g. ### Claim 21 (depends on 1) Process according to claim 1, wherein the conjugated diene monomer to be polymerized is isoprene in order to obtain a polyisoprene.