Process for polymerizing high melt index olefins and polymerization catalysts used therefore

Abstract

A process is disclosed for polymerizing an olefin to provide a polyolefin of high melt index which comprises contacting the olefin with a catalyst system obtained by heat activating a supported organophosphoryl chromium compound obtained by the reaction of chromium trioxide with an organophosphorous compound having the formula: ##STR1## wherein R is alkyl, aralkyl, aryl cycloalkyl, or hydrogen, but at least one R is other than hydrogen, and combining the heat activated supported material with a melt index increasing amount of at least one organoborane catalyst modifier having the formula: ##STR2## wherein m and n each is zero or 1, R.sub.1 and R.sub.2 are each a hydrocarbyl group of from 1 to 10 carbon atoms, or one of R.sub.1 and R.sub.2 is hydrogen, or together R.sub.1 and R.sub.2 constitute a hydrocarbyl group of from 2 to 10 carbon atoms.

Dependencies are inferred from the claim text.