Process for the preparation of polyolefin

• Main Authors: SUEYOSHI; TOMOKO, KOBATA; ATSUO, KAWASAKI; MASAAKI, MIYAKE; YOSHIO
• Format: Patent
• Language: English
• Published: 04.02.1997
• Edition: 6
• Subjects: CHEMISTRY; COMPOSITIONS BASED THEREON; COMPOSITIONS OF MACROMOLECULAR COMPOUNDS; MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVINGCARBON-TO-CARBON UNSATURATED BONDS; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP

A process for the preparation of polyolefin which comprises polymerizing or copolymerizing olefin in the presence of a catalyst for olefin polymerization comprising (A) a metallocene compound of a transition metal selected from the Group IVB of the periodic table, and (B) an organoaluminum oxy-compound; wherein the organoaluminum oxy-compound (B) is added to the polymerization system in the form of a slurry in an aliphatic hydrocarbon or alicyclic hydrocarbon, and the polymerization is carried out in the presence of the aliphatic hydrocarbon diluent or an alicyclic hydrocarbon diluent having a boiling point below 100 DEG C. In an embodiment of the invention a polymer solution containing the resulting polyolefin obtained from the polymerization process is fed to a separation zone kept at a temperature of not lower than the upper cloud point of the polymer solution to separate the polymer solution into a lower phase portion containing the polyolefin in a high concentration and an upper phase portion, so as to recover the polyolefin from the lower phase portion in the separation zone and to recycle at least a part of the upper phase portion to the polymerization zone.