PROCESS FOR ALPHA-OLEFIN GAS-PHASE POLYMERIZATION CONTROLLED BY THE SIMULTANEOUS ADDITION OF AN ACTIVATOR AND AN ACTIVITY RETARDER TO THE POLYMERIZATION MEDIUM

摘要

A process for controlling the continuous gas-phase polymerisation of one or more alpha-olefins in a fluidized and/or mechanically stirred bed reactor using a high activity catalyst based on a transition metal of groups IV, V or VI of the Periodic Table comprises introducing into the reactor, continuously and simultaneously, an activity retarder and an activator, in very small amounts, in a molar ratio and at flow rates which are varied with time in order to maintain substantially constant either the polymerization rata or the transition metal content of the polymer produced.