PROCESS FOR PREPARING POLYOLEFINS

摘要

An olefin is polymerized using a catalyst comprising a solid component and an organometallic compound. The solid component is obtained by contacting together a silicon oxide or an aluminium oxide, a hydroxyl group-containing compound, a magnesium halide or manganese halide with a titanium compound or vanadium compound supported thereon, and further, if required, an ether compound, each of these compounds being combined in accordance with particularly defined specified ratios. According to the process embodiment of this invention, polyolefins having a narrow particle size distribution and a reduced proportion of a finely powdered portion are obtained, and the bulk density thereof is very high. These characteristics are very advantageous in a polymerizing operation. In addition, those polyolefins, when subjected to molding, cause few problems.