Mobil Oil Corporation

Exxonmobil Oil Corporation

Bohumil V Kral

Grace O Tsien

David C Calabro

Chisung Wu

Pamela J Cook

A process is provided for producing an essentially linear copolymer of ethylene and a minor amount of a 1-olefin containing more than 2 carbon atoms comprising contacting said ethylene and 1-olefin with a Ziegler catalyst in a polymerization reaction zone at elevated temperature and pressure, contacting the polymerization reaction mixture containing polymer and unreacted monomers with a fresh supply of ethylene in a high pressure separation zone (HPS) operating at a lower pressure than the reaction zone such that the contents of the separation zone separates into a dense phase containing a major proportion of polymer, and a light phase containing a major proportion of unreacted monomers, and separately withdrawing the two phases from the separation zone. The polymer containing dense phase is then subsequently treated to obtain a purified polymer product, and at least a portion of the unreacted monomers in the light phase is generally re-used in the reaction, with or without some intermediate treatment or purification.

Process for the production of linear low density ethylene copolymers

There is disclosed a low density polymer having a broad molecular weight distribution, such that its melt flow ratio (MFR) is about 50 to about 250, and a substantially constant melt index-corrected density. The polymer, produced e.g., by blending a first polymer component of high molecular weight with a second polymer component of low molecular weight, with both polymer components having substantially the same melt index-corrected density, produces films having improved strength properties and low hexane extractables, as compared to films made from comparable individual polymer components. There is also disclosed a low density polymer, also having MFR of about 50 to about 250, having substantially no polymer chains having low molecular weight and short chain branches, which is prepared by blending a first polymer component of low density and high molecular weight with a second polymer component of relatively high density and relatively low molecular weight. The melt index-corrected densities of these two polymer components are dissimilar.

Broad distribution, high molecular weight low density polyethylene and

An olefin, particularly alpha-olefin, polymerization catalyst composition, supported on a refractory oxide support comprises two chromium specie: (1) CrO.sub.3 or any chromium compound calcinable to CrO.sub.3 ; and (2) at least one silylchromate compound. The composition is prepared by sequentially depositing specie (1) and (2) onto the same support.

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Victoria, Australia

Bohumil V Kral