Borealis Ag

Aki Aittola

Virginie Eriksson

Esa Kokko

Paivi Waldvogel

Thomas Garoff

Kalle Kallio

Päivi Waldvogel

Thomas Garroff

Kallio Kalle

Ziegler-Natta catalyzed linear low density polyethylene which satisfies the following conditions: a) a density, according to ISO 1183, of from 900 to 925 kg/m, b) a C-C-comonomer content, determined by Fourier transform infrared spectroscopy, of 1 to 16 wt % c) a weight average molecular weight Mw, determined by gel permeation chromatography, of at least 200 000, d) wherein the linear low density polyethylene comprises, by Crystallisation Analysis Fractionation (CRYSTAF) an amorphous fraction soluble at a temperature below 30&#xb0; C. of at most 10 wt % and a fraction crystallising between 60 to 75&#xb0; C. of at least 35 wt % and e) by temperature rising elution fractionation (TREF) analysis, at least 70 wt % of a crystallising polymer component having an elution temperature range from 60&#xb0; C. to 94&#xb0; C. and less than 10 wt % of a crystallising polymer component having an elution temperature range from 30&#xb0; C. to 60&#xb0; C. and, f) by Gel Permeation chromatography coupled with Fourier transform infrared spectroscopy detector (GPC-FTIR), a substantially constant short chain branching profile across the molecular weight distribution (MWD) or g) by Gel Permeation chromatography coupled with Fourier transform infrared spectroscopy instruments (GPC-FTIR), a reverse short chain branching profile across the molecular weight distribution (MWD), the linear low density polyethylene being produced in the presence of a special Ziegler-Natta procatalyst and a halogenated aluminium alkyl cocatalyst of the formula (IV) (C-C- alkyl)-Al-X, wherein X is chlorine, bromine, iodine or fluorine and m is 1 or 2.

Linear low density polyethylene with uniform or reversed comonomer composition distribution

A process is disclosed for producing a multi-modal linear low density polyethylene in at least two staged reactors connected in series, comprising (i) polymerizing in a first slurry phase stage ethylene monomers with a Ziegler-Natta polymerization catalyst system to obtain a first polyethylene fraction component (A); and (ii) polymerizing in a second gas or slurry phase stage ethylene monomers with a Ziegler-Natta polymerization catalyst system to obtain a second polyethylene fraction component (B). The Ziegler-Natta polymerization catalyst system comprises: 1) a solid procatalyst formed by contacting at least: a) a Mg-alcoholate complex of formula (I) b) an aluminum compound of formula (II); and c) a vanadium compound and a titanium compound having a molar ratio (V:Ti) from 10:90 to 90:10; and 2) one or more organometallic cocatalvsts of formula (III). The linear low density polyethylene shows an improved comonomer composition distribution Formulas (I), (II), and (III) are described herein.

Multi-stage process for producing multi-modal linear low density polyethylene

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Vasterskog, Finland

Aki Aittola