Gas-phase alpha-olefin polymerization process in the presence of an activity retarder

Abstract From the Canadian patent

A process for the continuous polymerization of one or more alpha-olefins with a transition metal catalyst in a reactor having, a fluidized and/or mechanically stirred bed in which a very small, amount of an activity retarder generally less than 0.1 ppm, is, introduced continuously into the reactor at a flow rate which is varied with time so as to keep substantially constant either the polymerization rate or the content of transition metal in the polymer produced. Suitable activity retarders include polymerization inhibitors such as, for example oxygen, alcohols, carbon monoxide and carbon dioxide and electron donor compounds such as amides and ethers.