GB1340621A - Method of producing solid polymers - Google Patents

Abstract

1340621 Olefin polymerization NAPHTACHIMIE 7 June 1971 [9 June 1970] 19257/71 Heading C3P Polymerization of C 2 to C 10 1-olefins is carried out in the absence of any liquid dispersion medium other than the monomer(s) and in the presence of a pre-polymer which is prepared by polymerizing one or more olefins in a liquid dispersion medium by means of a catalyst comprising a compound of a transition metal of Groups IVA to VIA and an organometallic compound of a metal of Groups II or III. The prepolymer is separated from the dispersion medium, soluble matter is separated from it by extraction with an aliphatic or cycloaliphatic hydrocarbon, and the residue, containing 500 to 10,000 ppm. of the transition metal and having a specific surface of at least 1 m<SP>2</SP>/g., is used to catalyze the polymerization, being first activated by the addition of an organometallic compound of Groups II or III. The polymerization is usually carried out in a fluidized bed using the monomer(s) as the fluidizing gas; an inert pre-formed polymer may also be present. A chain terminator, e.g. hydrogen, may be present in the prepolymerization and/or polymerization stages. Examples are given of the polymerization of ethylene using a pre-polymer prepared by polymerizing ethylene in the presence of TiCl 3 or TiCl 3 + Ti(OBu) 4 and Et 2 AlCl, Et 3 Al 2 Cl 3 or Et 3 Al, extracting the soluble polymer with hot heptane, and activating the residue with one of the same group of organoaluminium compounds or with triisobutyl or trioctyl aluminium.