Process for the gas-phase homo- or copolymerization of alpha-olefin with a pretreated catalyst system

Abstract

The polymerization of certain alpha-olefins in a gas phase involves the problem of agglomeration of the product into particles disadvantageous from the viewpoint of its handling. In the present invention this problem has been solved by means of a new type of process for the homo- or copolymerization of alpha-olefins. In the process the catalyst system is pretreated by contacting and reacting a transition-metal compound which is solid or on a solid carrier with an organoaluminum compound, and possibly an electron donor, in a liquid medium, and by drying the thus formed reaction product to produce a solid catalyst system. The thus pretreated solid and active catalyst system is then fed together with an alpha-olefin in the gaseous state into a gas-phase reactor, and polymerization is carried out by contacting them with each other. By feeding a dry and active catalyst system into the gas-phase reactor, it is possible to avoid the agglomeration of the product which occurs in conventional processes in which an organoaluminum compound and possibly an electron donor are fed in a liquid medium into the reactor.

Dependencies are inferred from the claim text.