Propylene polymerization catalyst system

摘要

The invention relates to a catalyst system for polymerization of propylene, the catalyst system comprising a Ziegler Natta procatalyst, an organoaluminium cocatalyst, a monoester of an aromatic carboxylic acid as the internal donor and ethyl-4-isopropoxy benzoate as the selectivity control agent. The invention also relates to a process for polymerization using the catalyst system as well as to polymers prepared by the process.

主权项

1. A catalyst system for the polymerization of propylene having a polymerization productivity of at least 2 kgPP/gcat and yielding polymers having a polydispersity index of less than 6, the catalyst system comprising a Ziegler-Natta procatalyst, an organoaluminium cocatalyst, ethyl benzoate as an internal donor and ethyl-4-isopropoxy benzoate as a selectivity control agent, wherein the cocatalyst to procatalyst molar ratio is in the range of 40 to 260 and the molar ratio of cocatalyst to selectivity control agent is in the range of 2 to 5.