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A method of forming a polymer that simultaneously provides an improved level of impact resistance and processability in which an .alpha.-olefin monomer is subjected to polymerization in the presence of a Ziegler-Natta catalyst system and a blend of electron donors including dicyclopentyldimethoxysil

A method of forming a polymer that simultaneously provides an improved level of impact resistance and processability in which an .alpha.-olefin monomer is subjected to polymerization in the presence of a Ziegler-Natta catalyst system and a blend of electron donors including dicyclopentyldimethoxysilane (DCPMS) and propyltriethoxysilane (PTES). The polymer so formed will have a relationship between a first melt flow rate of a homopolymer formed by polymerizing an .alpha.-olefin monomer in the presence of a Ziegler-Natta catalyst system and a first electron donor (MFR (a)), and a second melt flow rate of a homopolymer formed polymerizing an .alpha.-olefin monomer in the presence of the Ziegler-Natta catalyst system and a second electron donor (MFR (b)), is defined by the equation:EQU 1.2.ltoreq.log [MFR(b)/MFR(a)].ltoreq.1.4

대표청구항 ▼

[ What is claimed is:] [1.] A method of forming a polymer comprising:subjecting propylene monomers to polymerization in the presence of a Ziegler-Natta catalyst and a blend of at least two electron donors, said blend of electron donors comprising about 2.5 mol. % to less than 50 mol. % of a first el

[ What is claimed is:] [1.] A method of forming a polymer comprising:subjecting propylene monomers to polymerization in the presence of a Ziegler-Natta catalyst and a blend of at least two electron donors, said blend of electron donors comprising about 2.5 mol. % to less than 50 mol. % of a first electron donor based on total mol. % of electron donors wherein the first electron donor consists essentially of dicyclopentyldimethoxysilane (DCPMS) and greater than 50 mol. % of a second electron donor based on total mol. % of electron donors wherein the second electron donor consists essentially of propyltriethoxysilane (PTES) and wherein a relationship between the first electron donor and a second electron donor is defined by an equation;EQU 1.2.ltoreq.log [MFR(b)/MFR(a)].ltoreq.1.4wherein MFR(a) is a first melt flow rate of a homopolymer formed by polymerizing propylene monomers in the presence of the Ziegler-Natta catalyst and the first electron donor, and wherein MFR(b) is a second melt flow rate of a homopolymer formed by polymerizing propylene monomers in the presence of the Ziegler-Natta catalyst and the second electron donor, and wherein the MFR(a) is lower than the MFR(b).