Patent ID: 6323298
Filing Date: 2001-11-27
Classification: C08F

Abstract:
A method for producing a propylene-based polymer, which includes a step of polymerizing propylene using a polymerization catalyst which containsi) a solid catalyst component for polymerization;ii) an organoaluminum compound; andiii) a second electron-donating compound;wherein said solid catalyst component is one produced by(1) forming said solid catalyst component for polymerization comprising a magnesium compound, a titanium compound, a halogen compound and an electron-donating compound, wherein the molar ratio of the electron-donating compound (D) and the titanium content (T) incorporated therein is (D/T).sub.i, and(2) treating said solid catalyst component for polymerization to make a modified solid catalyst component for polymerization, said treating comprising:i) treating said solid catalyst component with an electron-donating compound for its incorporation or with a titanium compound represented by the general formula TiX.sub.a.Y.sub.b, wherein X is a halogen atom; a is 3 or 4; Y is an electron-donating compound, and 0<b.ltoreq.3, for its incorporation;ii) then treating and washing said solid catalyst component with a halogenous compound, andiii) further washing said solid catalyst component with a hydrocabon, wherein the molar ratio of the electron-donating compound (D) and the titanium content (T) incorporated in said solid catalyst component thus treated is (D/T).sub.m, such that (D/T).sub.m /(D/T).sub.i >1.