Aged lanthanide-based catalyst systems and their use in the preparation of cis-1,4-polydienes

Abstract

A method for preparing cis-1,4-polydienes, the method comprising the steps of preparing a preformed, active lanthanide-based catalyst, aging the active lanthanide-based catalyst for more than 5 days to thereby formed an aged catalyst, and introducing the aged catalyst and conjugated diene monomer to be polymerized to thereby form an active polymerization mixture in which the conjugated diene monomer is polymerized to form a polydiene having a reactive chain end.

1 - 17 . (canceled) 
     
     
         18 . A method for preparing a functionalized polymer, the method comprising:
 (a) preparing a catalyst composition by combining a lanthanide-containing compound, an alkylating agent, and a halogen source;   (b) aging the catalyst composition to form an aged catalyst composition;   (c) combining the aged catalyst composition, additional alkylating agent, and conjugated diene monomer to be polymerized to form a polymerization system that produces an a polydiene having a reactive chain end; and   (d) introducing a functionalizing agent to the polymerization system.   
     
     
         19 . The method of  claim 18 , where said step of preparing a catalyst composition includes combining conjugated diene monomer with the lanthanide-containing compound, the alkylating agent, and the halogen source. 
     
     
         20 . The method of  claim 18 , where said step of aging includes aging for at least 12 hours. 
     
     
         21 . The method of  claim 20 , where said step of aging includes aging for at least 3 days. 
     
     
         22 . The method of  claim 20 , where said step of aging includes aging at a temperature of at least 20° C. 
     
     
         23 . The method of  claim 19 , where said step of preparing a catalyst composition includes combining from about 1 to about 100 moles of conjugated diene monomer per mole of the lanthanide-containing compound. 
     
     
         24 . The method of  claim 18 , where said step of combining includes combining from about 0.001 to about 2 mmol of lanthanide-containing compound per 100 gram of conjugated diene monomer to be polymerized. 
     
     
         25 . The method of  claim 18 , where said step of preparing a catalyst composition includes combining neodymium neodecanoate, diisobutylaluminum hydride, and ethylaluminum sesquichloride.