Sumitomo Chemical Company, Limited

Mamoru Asada

Akinobu Shiga

Kiyoshi Matsuyama

Masahiro Kakugo

A process for producing a propylene polymer or copolymer which comprises polymerizing (a) propylene or (b) a mixture of propylene and another unsaturated hydrocarbon monomer in liquid propylene in the presence of a catalyst system of

Process for producing propylene polymer or copolymer

A process for producing a homopolymer of propylene or a copolymer of propylene which comprises polymerizing propylene or a mixture of propylene and another unsaturated hydrocarbon monomer such as ethylene in liquid propylene, in the presence of a catalyst system consisting essentially of (a) an activated titanium compound obtained by reducing titanium tetrachloride with an organic aluminum compound and activating the resulting titanium compound and (b) an organic aluminum compound to produce a polymer slurry, introducing the polymer slurry into an upper part of a counter-current washing zone, such as a washing tower, and counter-currently contacting the polymer slurry with liquid propylene which is introduced into a lower part of the washing zone, whereby the polymer and catalyst residues dissolved in the polymer slurry are removed.

Process for producing propylene homopolymers and copolymers

A process for polymerizing .alpha.-olefins in a solvent under conditions such that the polymer formed grows as particles, in which the process comprises reusing a greater part of the solvent used for the polymerization by recycling the solvent to the polymerization zone without carrying out any purification treatment.

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Niihama, Japan

Mamoru Asada