Exxon Research and Engineering Company

Exxon Chemical Patents, Inc.

Eugene E Poirot

Terrence Huff

Harry J Wristers

Scott K Jackson

Vispi R Sagar

The present invention relates to a gas phase process for the polymerization of olefins utilizing a metallocene catalyst system to produce polymers having a low density and a relatively high molecular weight. More particularly, the gas phase process of the invention is directed forward the production of very low density polymers, for example rubbers, elastomers and plastomers.

Gas phase polymerization process

A aliphatic hydrocarbon soluble mixed aluminum hydrocarbyl-Lewis base co-catalyst composition comprising (i) at least two different classes of aluminum hydrocarbyls the first being an aluminum hydrocarbyl halide, the second being an aluminum hydrocarbyl hydride and/or aluminum trialkyl and (ii) at least one Lewis base represented by the formula: ##STR1## wherein each Y can be -OR', -NR.sub.2 ' and R' with the proviso that at least two be -OR' or -NR.sub.2 ', Z is an alkylene radical forming a 5 or 6 membered ring with the carbonyldioxy group or Z is alkyl substituted alkylene group wherein the alkyl radical can have from 1 to 8 carbon atoms, R is an aryl, allyl or alkyl group having 1 to 20 carbon atoms and R' is an alkyl, cycloalkyl, aryl or aralkyl radical having from 1 to 20 carbon atoms. The co-catalyst is employed with a titanium halide catalyst for the polymerization of olefins to obtain a advantageous balance of catalytic activity and polymer product stereoregularity.

High efficiency polymerization catalyst component for use in the

Polyolefins are prepared wherein at least about ninety-five percent of the product is retained on a 100 mesh screen. The polymerization process involves contacting the alpha-olefin with a Ziegler catalyst system wherein the catalyst has been prepared by mixing the active catalytic particles with a fibrillatable polyolefin and a non-fibrillatable polyolefin followed by ballmilling the mixture for a period of time sufficient to cause a fibrous mat to form, entrapping the catalyst particles in the mat which is, in turn, carried by the non-fibrillatable polyolefin.

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Baytown, TX, United States of America

Eugene E Poirot