Patent ID: 6127303
Filing Date: 2000-10-03
Classification: C08F

Abstract:
A catalyst system for polymerizing olefins formed from the constituents comprising:(A) a solid catalyst component containing magnesium, titanium, halogen and electron donative compound as essential components, wherein the electron donative compound contained in the solid catalyst component (A) is selected from the group consisting of esters of organic and inorganic acids and ethers, wherein the esters of organic acids are esters of mono-carboxylic acids or poly-carboxylic acids;wherein the ether is at least a dialkyl ether compound represented by the following general formula: ##STR2## wherein R.sup.4, R.sup.5, R.sup.6 and R.sup.7 each represents a linear or branched alkyl group having 1-20 carbon atoms, an alicyclic group, an aryl group, an alkylaryl group or an arylalkyl group provided that R.sup.4 to R.sup.7 can be identical with or different from one another, and that each of R.sup.4 and R.sup.5 can be a hydrogen atom; andwherein the ester of an inorganic acid is at least one silicon compound represented by the following general formula:R.sup.2.sub.n Si(OR.sup.3).sub.4-nwherein R.sup.2 represents a hydrocarbon group having 1-20 carbon atoms or a hydrogen atom, R.sup.3 represents a hydrocarbon group having 1-20 carbon atoms and n represents a number satisfying 0.ltoreq.n.ltoreq.4,(B) an organoaluminum compound, and(C) at least two electron donative compounds including electron donative compound (.alpha.) and electron donative compound (.beta.),wherein the electron donative compound (.alpha.) is an organic silicon compound represented by the following formula:R.sup.13 R.sup.14 Si(OR.sup.15).sub.2,wherein R.sup.13 represents a hydrocarbon group in which the carbon atom adjacent to Si is a secondary or tertiary carbon atom wherein R.sup.13 is selected from the group consisting of cyclopentyl, cyclohexyl, cyclopentenyl phenyl and tolyl and each of R.sup.14 and R.sup.15 independently represents a C.sub.1 -C.sub.20 hydrocarbon group, andwherein the electron donative compound (.beta.) is an organic silicon compound represented by the following formula:R.sup.16 R.sup.17 Si(OR.sup.18).sub.2,wherein R.sup.16 represents a straight chain alkyl group selected from the group consisting of propyl, butyl and hexyl, R.sup.17 represents a hydrocarbon group having one carbon atom and R.sup.18 represents a C.sub.1 -C.sub.5 hydrocarbon group; andwherein the total amount of electron donative compounds (C) is present in an amount of from 0.01 to 1 mole per mole of compound (B).