Preparation of propylene homopolymers or copolymers

摘要

The disclosure is directed to an improvement in the gas phase polymerization of propylene using a Ziegler-Natta catalyst in the presence of hydrogen wherein the gaseous propylene is withdrawn from the reactor, cooled and condensed and returned as a liquid to the reactor in order to regulate the polymerization temperature. The amount of the gaseous phase in the condenser-cooler-accumulator system is kept constant by regulating the amount of gaseous phase returned to the reactor.