Patent ID: 8461280
Filing Date: 2013-06-11
Classification: C08F,C08L

Abstract:
1. A process for the manufacture of a multimodal linear low density polyethylene polymer comprising: in a first stage polymerising ethylene and optionally at least one α-olefin in the presence of a Ziegler-Natta catalyst which comprises a solid catalyst component which is formed at least from wherein the catalyst component of said Ziegler Natta catalyst is formed by an emulsion/solidification method, and is modified by one or more organic ligand compounds which are selected from organic compounds comprising a cyclopentadienyl anion backbone; so as to form 30 to 60 wt % of a lower molecular weight component (A) wherein (A) is an ethylene homopolymer or a copolymer of ethylene and at least one α-olefin; and transferring the product of the first stage to a second stage and in a second stage polymerising ethylene and at least one α-olefin in the presence of the same catalyst to form 70 to 40 wt % of a higher molecular weight component (B); wherein (B) is a copolymer of ethylene and at least one α-olefin, wherein said α- olefin is the same or different from any α-olefin used in component (A) but wherein both components (A) and (B) are not polymers of ethylene and butene alone; so as to form a multimodal linear low density polyethylene polymer which has a final density of 900 to 940 kg/m wherein the multimodal linear low density polyethylene polymer has a dart drop of at least 700g, and the molecular weight distribution of the multimodal linear low density polyethylene polymer is in the range 7 to 22.