still for the polymerisation of at least one olefin - 3 - 6 carbon atoms in the nervaro of a catalyst of (a) a magnesian solid titankomposition and (b) a organoaluminiumforening

摘要

An improved process for preparing a highly stereoregular polymer or copolymer of an olefin containing at least 3 carbon atoms using a catalyst system comprising a magnesium-containing solid titanium composition prepared from a specific alkoxy- and/or aryloxy-containing, halogen-free organic magnasium compound which can obviate the troubles that would normally be caused by the presence of moisture during storage of raw materials for catalysts or during catalyst preparation if halogen-containing magnesium compounds are used and which can ensure superior reproducibility of catalyst performance.