Union Carbide Chemicals & Plastics Technology Corporation

Thomas L Nemzek

Linfeng Chen

Frederick John Karol

Sun-Chueh Kao

Robert Converse Brady, Iii

Richard Alan Kemp

A method of making a solid procatalyst composition for use in a Ziegler-Natta olefin polymerization catalyst composition, said method comprising:

Olefin polymerization catalyst compositions and method of preparation

A catalyst composition for the polymerization of olefins and process for the use thereof, comprising the combination of one or more Ziegler-Natta catalysts, comprising one or more transition metal compounds, one or more aluminum containing cocatalyts, and a mixture of different selectivity control agents, including in said mixture of selectivity control agents at least one normally dominating selectivity control agent and one normally dominated selectivity control agent, characterized in that the individual selectivity control agents are present in the mixture in relative amounts to each other and relative to the one or more transition metal compounds, such that the effect of the selectivity control agents on the resulting polymer properties is not determined solely or substantially solely by the normally dominating selectivity control agent.

Catalyst composition and polymerization process using mixtures of selectivity control agents

It has been found that the use of at least one unsupported metallocene polymerization catalyst with at least one supported metallocene polymerization catalyst in the polymerization of olefins allows for better control of the polymerization, especially gas phase polymerization. Such a system takes advantage of the high activity of the unsupported catalyst and the stability of a supported catalyst. Additionally, the relative timing of the addition of the supported and unsupported catalysts to a reaction system can be used to control a continuous polymerization reaction by stabilizing the reactor bed with the supported catalyst prior to addition of the unsupported catalyst.

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Katy, TX, United States of America

Thomas L Nemzek