Patent ID: 6300437
Filing Date: 2001-10-09
Classification: C08F,Y10S

Abstract:
A process for the preparation of a copolymer of ethylene and an alpha-olefin having from 3 to 20 carbon atoms characterised in having(a) a flow activation energy (E.sub.a) in the range 50.ltoreq.E.sub.a.ltoreq.200 kJ/mol,(b) a degree of long chain branching (LCB/1000C) as measured by GPC/solution viscometry in the range 0.25.ltoreq.LCB.ltoreq.0.03 E.sub.a =1.5 and(c) a breadth of molecular weight distribution M.sub.w /M.sub.n greater than 2.5,said process comprising polymerising in a gas phase ethylene and an alpha-olefin having from 3 to 20 carbon atoms in the presence of an unprepolymerized supported catalyst comprising a metallocene complex having the general formula: ##STR4##whereinCp.sup.1, Cp.sup.2 are independently a substituted or unsubstituted indenyl or hydrogenated indenyl group,Y is a univalent anionic ligand,M is zirconium, titanium or hafnium, andZ is a bridging group comprising an alkylene group having 1 and 20 carbon atoms or a dialkyl silyl- or germanyl-group, or alkyl phophine or amine radical.