Components and catalysts for the polymerization of olefins.

摘要

The present invention relates to spherical solid components of catalysts for the polymerization of olefins comprising, supported on a magnesium dihalide in active form, a titanium compound containing at least one Ti-halogen bond and one OR group, said OR group being bonded to Ti in an amount such that the OR/Ti molar ratio is greater than or equal to 0.5; optionally the component also comprises an electron donor compound. The spherical solid components of the invention are characterized by having a porosity comprised between 0.35 and 0.7 cm<3>/g and by a pore size distribution such that at least 50% of the porosity is due to pores having an average radius greater than 800 ANGSTROM .