The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 04, 2003
Filed:
Nov. 08, 2000
Ole Jan Myhre, Pregarten, AT;
Bjarne Jansen, Porsgrunn, NO;
Auli Nummila-Pakarinen, Porvoo, FI;
Jari Äärilä, Porvoo, FI;
Borealis Technology Oy, Porvoo, FI;
Abstract
The present invention concerns a process for producing homogeneous polyethylene compositions and processes for making high density, medium density and low density films therefrom. The process comprises carrying out the polymerization in the presence of an ethylene-polymerizing catalyst system in a multistage reaction sequence of successive polymerization stages, at least one of which is a loop polymerization stage, and at least one of which is a gas phase polymerization stage. According to the invention, said loop polymerization stage is operated using a diluent selected from the group of linear and branched C -C hydrocarbons and/or mixtures thereof. The reactor sequence is operated with different amounts of hydrogen and comonomers to produce a high molecular weight portion in one of the polymerization stages and a low molecular weight portion in another, so as to provide bimodal polyethylene composition with a low molecular weight part having an MFR of 250 g/10 min or more. The obtained material is homogenous and the fines level in the process is low.