US 11,702,489 B2
Production method of propylene polymer
Takayuki Mitani, Osaka (JP)
Assigned to SUMITOMO CHEMICAL COMPANY, LIMITED, Tokyo (JP)
Filed by Sumitomo Chemical Company, Limited, Tokyo (JP)
Filed on Feb. 8, 2021, as Appl. No. 17/169,620.
Claims priority of application No. 2020-023720 (JP), filed on Feb. 14, 2020.
Prior Publication US 2021/0253756 A1, Aug. 19, 2021
Int. Cl. C08L 23/14 (2006.01); C08F 210/16 (2006.01); C08F 2/01 (2006.01); C08F 210/06 (2006.01); C08F 10/06 (2006.01); C08F 2/34 (2006.01); C08L 23/08 (2006.01); C08F 2/00 (2006.01)
CPC C08F 210/06 (2013.01) [C08F 2/001 (2013.01); C08F 2/34 (2013.01); C08F 10/06 (2013.01); C08F 210/16 (2013.01); C08L 23/0815 (2013.01); C08L 2207/02 (2013.01)] 7 Claims
 
1. A method of producing a propylene polymer, comprising (co)polymerizing at least one monomer comprising propylene in a presence of an olefin polymerization catalyst with: (a) a polymerization system comprising two or more gas phase polymerization reactors, or (b) a polymerization system comprising at least one liquid phase polymerization reactor and at least one gas phase polymerization reactor such that a total number of the liquid phase polymerization reactors and the gas phase polymerization reactors in the polymerization system (a) or (b) is three or more, wherein
at least one gas phase polymerization reactor in the polymerization system (a) or (b) is such that an operation performance evaluation index f defined by the following formula (A) is not less than 30 and not more than 1250:
f=(exp(Co))a·τGb·Dpic  (A)
where τG is an average retention time [hour] in a gas phase polymerization in question,
Dpi is an average particle diameter [μm] of fed powder, and
Co is a total amount [wt %] of an ethylene-derived structural unit and C4-C12 α-olefin-derived structural units in a polymer in discharged powder,
where a=−0.50, b=2.50, and c=0.65.