Equistar Chemicals, LP

Natalia Nagy

Sandor M Nagy

Jean A Merrick-Mack

Barbara M Tsuie

Mark P Mack

Edward S Vargas

Charles H Gates, Jr

Charles S Holland

Venki Chandrashekar

Bradley P Etherton

Linda N Winslow

Sebastian Joseph

Everett O Lewis

Disclosed is a polyethylene composition. The composition comprises single-site multimodal resin A and single-site multimodal resin B, wherein resin A differs from resin B in molecular weight, in monomeric composition, in density, in long chain branch concentration or distribution, or in combinations thereof. Disclosed is also a method for making the polyethylene composition. The method comprises polymerizing, in the presence of two or more single-site catalysts, ethylene or its mixture with a C-C&#x3b1;-olefin to form a first multimodal resin and continuing the polymerization in the presence of the same catalysts but in a different hydrogen concentration, in a different monomer composition, or at a different temperature to form a second multimodal resin.

Preparation of multimodal polyethylene

A slurry process for polymerizing ethylene is disclosed. The process comprises polymerizing ethylene in a first reactor in the presence of hydrogen and a catalyst comprising an activator and a supported dimethylsilyl-bridged indeno[1,2-b]indolyl zirconium complex to produce an ethylene homopolymer, removing some of the unreacted hydrogen, and reacting the homopolymer slurry in a second reactor with ethylene and a C-C&#x3b1;-olefin to produce polyethylene. The polyethylene has weight-average molecular weight greater than 150,000, broad molecular weight distribution, low long-chain branching, and it provides pipes or molded articles with good environmental stress crack resistance.

Olefin polymerization process

A slurry process for polymerizing ethylene is disclosed. The process comprises polymerizing ethylene in the presence of an &#x3b1;-olefin, hydrogen, and a catalyst comprising an activator and a supported, dimethylsilyl-bridged bis(indenoindolyl)zirconium complex. The process has high catalyst activity and produces polyethylene having a broad molecular weight distribution.

A slurry process for polymerizing ethylene is disclosed. The process comprises polymerizing ethylene in the presence of an &#x3b1;-olefin and a catalyst comprising an activator and a supported bridged bis-indeno[2,1-b]indolyl zirconium complex. The process uses a highly active catalyst and provides polyethylene characterized by a high level of long-chain branching.

A slurry process for polymerizing ethylene is disclosed. The process comprises polymerizing ethylene in the presence of an &#x3b1;-olefin and a catalyst comprising an activator and a supported bridged indeno[1,2-b]indolyl zirconium complex. The process produces polyethylene characterized by good incorporation of the &#x3b1;-olefin and moderate long-chain branching. The process is capable of forming high molecular weight polyethylene and has good catalyst activity.

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Naperville, IL, United States of America

Natalia Nagy