Univation Technologies, LLC

Mark P Ossowski

Rainer Kolb

James McLeod Farley

John Francis Szul

Blair Alfred Graham

Christopher R Davey

John F Szul

James M Farley

The invention generally provides for methods for controlling polymer properties. In particular, invention provides for methods for controlling the comonomer composition distribution of polyolefins such as ethylene alpha-olefin copolymers by altering at least one or more of the following parameters: the molar ratio of hydrogen to ethylene, the molar ratio of comonomer to ethylene, the partial pressure of ethylene, and the reactor temperature without substantially changing the density and/or the melt index of the copolymer.

Methods of controlling polymer properties

A process for the production of an ethylene alpha-olefin copolymer is disclosed. The process includes polymerizing ethylene and at least one alpha-olefin by contacting the ethylene and the at least one alpha-olefin with a metallocene catalyst in at least one gas phase reactor at a reactor pressure of from 0.7 to 70 bar and a reactor temperature of from 20&#xb0; C. to 150&#xb0; C. to form an ethylene alpha-olefin copolymer. The resulting ethylene alpha-olefin copolymer may have a density of 0.927 g/cc or greater and environmental stress crack resistance (ESCR) of 500 hr or more when measured according to ASTM 1693/B in 10% Igepal.

Ethylene alpha olefin copolymers and polymerization processes for making the same

Ethylene alpha-olefin copolymers formed by contacting at least one supported metallocene catalyst, ethylene, and an alpha-olefin in a gas phase reactor are disclosed. In some embodiments, the polymer may have: a density of between 0.890 and 0.970 g/cc; a melt index of between 0.7 and 200 dg/min; a melt index ratio of less than 30; an ESCR value of greater than 1000 hours; and a 1% secant modulus of greater than 75,000 psi. In other embodiments, the polymer may have: a density of between 0.930 g/cc and 0.970 g/cc; a melt index of between 10 dg/min and 200 dg/min; a melt index ratio of between 10 and 25; a part weight of greater than 3 g and a part length of greater than 38 cm in a spiral flow test, and; a zero shear viscosity of less than 150 Pa&#xb7;s. Processes to produce these polymers are also disclosed.

Polymers made with metallocene catalysts, for use in rotomolding and injection molding products

Ethylene-alpha olefin copolymers and polymerization processes for making the same

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Bridgewater, NJ, United States of America

Mark P Ossowski