US 11,725,069 B2
Method for producing polypropylene
Hyo Seung Park, Daejeon (KR); Hyeong Min Kim, Daejeon (KR); Sung Jae Na, Daejeon (KR); Ji Hae Park, Daejeon (KR); and So Young Shim, Daejeon (KR)
Assigned to SK Innovation Co., Ltd., Seoul (KR); and SK Geo Centric Co., Ltd., Seoul (KR)
Filed by SK Innovation Co., Ltd., Seoul (KR); and SK Geo Centric Co., Ltd., Seoul (KR)
Filed on Oct. 13, 2021, as Appl. No. 17/500,012.
Claims priority of application No. 10-2020-0133188 (KR), filed on Oct. 15, 2020.
Prior Publication US 2022/0119560 A1, Apr. 21, 2022
Int. Cl. C08F 110/06 (2006.01); C08F 4/642 (2006.01); C08F 4/659 (2006.01)
CPC C08F 110/06 (2013.01) 13 Claims
 
1. A method of producing polypropylene, the method comprising polymerizing propylene in the presence of a catalyst composition comprising a Ziegler-Natta catalyst, an external electron donor, dialkylaluminum hydride, and trialkylaluminum, wherein the polypropylene has a xylene cold soluble content of 3 wt % or less, and
wherein the polypropylene has, when an endothermic peak is measured using successive self-nucleation and annealing (SSA)-differential scanning calorimeter (DSC), a sum of a peak value (DH4) observed at 170° C. and a peak value (DH5) observed at 176° C. of 75% or more of a total peak.