PROPYLENE/OLEFIN RANDOM COPOLYMER AND METHOD FOR PRODUCING THE SAME

摘要

PROBLEM TO BE SOLVED: To obtain a propylene/olefin random copolymer having a low melting point and a high bulk specific gravity, and excellent in low-temperature heat- sealable properties. SOLUTION: This propylene/olefin random copolymer containing 0.1-30 wt.% olefin is produced by using a catalyst system in order for polymerizing the olefin, comprising a metallocene carrying type catalyst obtained by carrying out the following steps in order, and an organoaluminum compound by a vapor- phase polymerizaiton process: (a) a step for obtaining the metallocene catalyst by reacting an organic transition metal compound having two crosslinkedπelectron conjugated ligands with an aluminoxane in an inert solvent to provide the metallocene catalyst; (b) a step for obtaining a crude metallocene-carrying type catalyst by bringing the resultant metallocene catalyst into contact with an inorganic particulate carrier in the presence of the inert solvent at 85-150 deg.C, and (c) a step for obtaining the objective purified metallocene-carrying type catalyst by washing a slurry containing the crude metallocene-carrying type catalyst at (-50)-50 deg.C with an aliphatic hydrocarbon at least twice to purify the metallocene-carrying type catalyst.