Patent ID: 6841634
Filing Date: 2005-01-11
Classification: C08F,Y10S

Abstract:
1. A process for preparing polyolefins comprising (I) prepolymerising a supported olefin polymerization catalyst with an olefin or olefin mixture wherein the pre-polymerization olefin or olefin mixture is one or more of 1-butene, 3-methyl-1-butene, 3,3-dimethyl-1-butene, 4-methyl-1-pentene, 4,4-di methyl-1-pentene, 4,5-dimethyl-1-hexene, vinyl cyclopentane, vinyl cyclohexane, vinyl cycloheptane, allyl cyclopentane, allyl cyclohexane or alyll cycloheptane; (II) isolating the resulting prepolymerised olefin polymerisation catalyst; and (III) polymerising or copolymerising olefins in the presence of the prepolymerised olefin polymerisation catalyst; wherein the olefin or olefin mixture of the prepolymerisation is different from that of the subsequent olefin polymerisation or copolymerisation, wherein the melting point or softening point of the polyolefin or olefin copolymer resulting from prepolymerisation is at least 20° C. higher than the melting point or softening point of the polyolefin or olefin copolymer of the subsequent olefin polymerisation and wherein said olefin polymerisation catalyst is a metallocene.