A Method for Producing Functionalized Cis-1
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(19) TZZ_¥ __T (11) EP 1 939 221 B1 (12) EUROPEAN PATENT SPECIFICATION (45) Date of publication and mention (51) Int Cl.: of the grant of the patent: C08C 19/44 (2006.01) C08F 36/04 (2006.01) 18.10.2017 Bulletin 2017/42 C08F 4/54 (2006.01) C08L 15/00 (2006.01) B60C 1/00 (2006.01) (21) Application number: 07255064.3 (22) Date of filing: 27.12.2007 (54) A METHOD FOR PRODUCING FUNCTIONALIZED CIS-1,4POLYDIENES HAVING HIGH CIS-1,4-LINKAGE CONTENT AND HIGH FUNCTIONALITY VERFAHREN ZUR HERSTELLUNG VON FUNKTIONALISIERTEN CIS-1,4-POLYDIENEN MIT HOHEM 1,4-BINDUNGSGEHALT UND HOHER FUNKTIONALITÄT PROCÉDÉ DE PRODUCTION DE POLYDIÈNES CIS- 1,4 FONCTIONNALISÉS AYANT UN FORT CONTENU DE LIAISON CIS-1,4 ET UNE FONCTIONNALITÉ ÉLEVÉE (84) Designated Contracting States: •Ozawa,Yoichi DE ES FR GB IT Tokyo 187-8531 (JP) • Tartamella, Timothy L. (30) Priority: 28.12.2006 US 877535 P Silver Lake Ohio 44224 (US) • Smale, Mark (43) Date of publication of application: Hudson Ohio 44236 (US) 02.07.2008 Bulletin 2008/27 (74) Representative: Oxley, Robin John George et al (73) Proprietor: Bridgestone Corporation Marks & Clerk LLP Tokyo 104-8340 (JP) 90 Long Acre London WC2E 9RA (GB) (72) Inventors: • Luo, Steven (56) References cited: Copley OH 44321 (US) EP-A- 0 713 885 WO-A-2006/112450 • Kurazumi, Junko JP-A- 59 131 609 US-A1- 2005 197 474 Tokyo 187-8531 (JP) Note: Within nine months of the publication of the mention of the grant of the European patent in the European Patent Bulletin, any person may give notice to the European Patent Office of opposition to that patent, in accordance with the Implementing Regulations. Notice of opposition shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). EP 1 939 221 B1 Printed by Jouve, 75001 PARIS (FR) EP 1 939 221 B1 Description FIELD OF THE INVENTION 5 [0001] This invention relates to methods for producing cis-1,4-polydienes having a combination of a high cis-1,4- linkage content and a high percentage of reactive polymer chains. The methods employ a particular lanthanide-based catalyst system. The polydienes can be functionalized to produce polymers having a high degree of functionality. Also, certain lanthanide-based catalyst systems can be employed to produce polymers having a narrow molecular weight distribution. 10 BACKGROUND OF THE INVENTION [0002] Functionalized polymers can be prepared by anionic polymerization methods, e.g., by initiating polymerization of 1,3-butadiene with a functionalized initiator and/or by reacting a living anionic polymer with a functionalizing agent. 15 The functionalized polymers made by anionic polymerization methods can have a high functionality, resulting in polymers that have a greater affinity toward carbon black or silica fillers than non-functionalized polymers. Therefore, the rubber vulcanizates made from the functionalized polymers give lower hysteresis loss than those made from non-functionalized polymers. Unfortunately, stereoregular polymers such as cis-1,4-polydienes, which are often required for the manufacture of certain tire components, cannot be obtained by anionic polymerization methods because these methods do not provide 20 strict control over the polymer microstructure such as the cis-1,4-linkage content of a polydiene polymer. [0003] Coordination catalysts (also known as Ziegler-Natta catalysts), such as lanthanide-based catalysts comprising a lanthanide compound, an alkylating agent, and a halogen-containing compound, are often highly stereoselective. These catalysts can produce conjugated diene polymers having high cis-1,4-linkage contents. The resulting cis-1,4- polydienes are particularly suitable for use in tire components such as sidewalls and treads. Nevertheless, the use of 25 coordination catalysts in polymerization limits the ability to functionalize the resulting polymers because coordination catalysts operate by rather complex chemical mechanisms that involve the interaction among several catalyst compo- nents and often involve self-termination reactions. As a result, it is difficult to prepare highly functionalized polymers under ordinary conditions by using coordination catalysts. [0004] Cis-1,4-polydienes that are prepared via solution polymerization processes catalyzed with lanthanide-based 30 catalysts are known to display some degree of pseudo-living characteristics, such that some of the polymer chains possess reactive chain ends. Accordingly, these cis-1,4-polydienes may react with certain functionalizing agents, such as aminoketones, heterocumulene compounds, three-membered heterocyclic compounds, organometallic halides, and certain other halogen-containing compounds. Unfortunately, due to the above-mentioned limitations associated with a coordination catalyst, the resulting functionalized cis-1,4-polydienes generally have a lower functionality as compared 35 to other functionalized polymers that are produced by anionic polymerization methods. WO2006/112450 discloses a method of producing a modified conjugated diene polymer using a lanthanide compound in an organic solvent which is subsequently modified with a functionalizing agent. [0005] Therefore, there is a need to develop a method for producing functionalized cis-1,4-polydienes that have a combination of a high cis-1,4-linkage content and a high functionality. 40 BRIEF SUMMARY OF THE INVENTION [0006] The present invention provides a method for producing a functionalized cis-1,4-polydiene, the method com- prising the steps of: (1) preparing a reactive polymer by polymerizing conjugated diene monomer with a lanthanide- 45 based catalyst in the presence of less than 20% by weight of organic solvent based on the total weight of monomer, organic solvent, and resulting polymer, where the lanthanide-based catalyst is the combination of or reaction product of (a) a lanthanide compound, (b) an aluminoxane, (c) an organoaluminium compound other than an aluminoxane, and (d) a halogen-containing compound; and (2) contacting the reactive polymer with a functionalizing agent, where the molar ratio of the aluminoxane to the lanthanide compound (Al/Ln) is from 5:1 to 1000:1, the molar ratio of the organoa- 50 luminium compound to the lanthanide compound (organo-Al/Ln) is from 1:1 to 200:1, and the molar ratio of the halogen- containing compound to the lanthanide compound (halogen/Ln) is from 2:1 to 6:1; to thereby produce a polymer with a cis-1,4-linkage content of greater than or equal to 99% and a functionality of greater than or equal to 80%, where the functionality is defined as the percentage of polymer chains comprising at least one functional group versus the total polymer chains in a polymer product.. 55 [0007] Further preferred embodiments of the invention are set out in dependent claims 2 to 5. 2 EP 1 939 221 B1 DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS [0008] The present invention is directed toward a method for producing cis-1,4-polydienes having an advantageously high percentage of polymer chains with reactive chain ends. These polydienes are generally produced by polymerizing 5 conjugated diene monomer with a lanthanide-based catalyst system within a bulk polymerization system to form the reactive polymers. The lanthanide-based catalyst system includes the combination of or reaction product of (a) an lanthanide compound, (b) an aluminoxane, (c) an organoaluminum compound other than an aluminoxane, and (d) a halogen-containing compound. In one or more embodiments, where the halogen-containing compound is an iodine- containing compound, the resultant cis-1,4-polydienes advantageously have a narrow molecular weight distribution. 10 Also, the reactive polymers are reacted with certain functionalizing agents to form functionalized polymers having a combination of a high cis-1,4-linkage content and an unexpectedly high functionality. The resultant functionalized poly- mers can be used in the manufacture of tire components. [0009] The present inventors have unexpectedly found that functionalized cis-1,4-polydienes having a combination of a high cis-1,4-linkage content and a high functionality can be produced by a method comprising the steps of: (1) preparing 15 a reactive polymer by polymerizing conjugated diene monomer with a lanthanide-based catalyst in the presence of less than 20% by weight of organic solvent based on the total weight of monomer, organic solvent, and resulting polymer, where the lanthanide-based catalyst is the combination of or reaction product of (a) a lanthanide compound, (b) an aluminoxane, (c) an organoaluminium compound other than an aluminoxane, and (d) a halogen-containing compound; and (2) contacting the reactive polymer with a functionalizing agent, where the molar ratio of the aluminoxane to the 20 lanthanide compound (Al/Ln) is from 5:1 to 1000:1, the molar ratio of the organoaluminium compound to the lanthanide compound (organo-Al/Ln) is from 1:1 to 200:1, and the molar ratio of the halogen-containing compound to the lanthanide compound (halogen/Ln) is from 2:1 to 6:1; to thereby produce a polymer with a cis-1,4-linkage content of greater than or equal to 99% and a functionality of greater than or equal to 80%, where the functionality is defined as the percentage of polymer chains comprising at least one functional group versus the total polymer chains in a polymer product. In one 25 or more embodiments, other organometallic compounds, Lewis bases, and/or catalyst modifiers may be employed in addition to the ingredients (a)-(d). In one embodiment, a nickel-containing compound may be employed as a molecular weight regulator as disclosed in U.S. Pat. No. 6,699,813. [0010] Various conjugated diene monomers or mixtures thereof can be used in the practice of the present invention. Specific examples of conjugated diene monomers include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-ethyl- 30 1,3-butadiene, 2-methyl-1,3-pentadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 4-methyl-1,3-pentadiene, 1,3-hexa- diene, and 2,4-hexadiene.