US 12,479,935 B2
Polymerization processes for the production of cis-1,4-polydienes
Steven M. Baldwin, Akron, OH (US); and Walter A. Salamant, Akron, OH (US)
Assigned to Bridgestone Corporation, Chuo-ku (JP)
Appl. No. 17/787,749
Filed by Bridgestone Corporation, Tokyo (JP); Steven M. Baldwin, Akron, OH (US); and Walter A. Salamant, Akron, OH (US)
PCT Filed Dec. 22, 2020, PCT No. PCT/US2020/066654
§ 371(c)(1), (2) Date Jun. 21, 2022,
PCT Pub. No. WO2021/133819, PCT Pub. Date Jul. 1, 2021.
Claims priority of provisional application 62/952,955, filed on Dec. 23, 2019.
Prior Publication US 2023/0089837 A1, Mar. 23, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. C08F 4/54 (2006.01); C08F 136/04 (2006.01); C08F 136/08 (2006.01)
CPC C08F 136/08 (2013.01) 20 Claims
OG exemplary drawing
 
1. A process for preparing a polydiene, the process comprising:
(i) preparing an active catalyst composition by combining (a) a rare-earth metallocene compound including gadolinium, (b) an alkylating agent, (c) an aluminoxane, and optionally (d) a halogen-containing compound, where the catalyst composition includes halogen at molar ratio to a rare-earth metal of from about 0.5:1 to about 2.0:1; and
(ii) introducing the active catalyst composition to conjugated diene monomer.