Patent ID: 6432860
Filing Date: 2002-08-13
Classification: C08F,Y02P,Y10S

Abstract:
A supported metallocene catalyst comprising:a) a particulate silica support comprising spheroidal silica particles having an average diameter within the range of 5-40 microns and an average effective pore size within the range of 50-350 Angstroms with at least 50% of the surface area of said support being contained within the pore volume of said particulate support wherein at least some of said spheroidal silica particles comprise a central bore extending at least partially through said particle to provide a toroidal shaped configuration; b) a stereospecific metallocene supported on said particulate support and incorporating a metallocene ligand structure having two sterically dissimilar cyclopentadienyl ring structures coordinated to a central transition metal atom; at least one of said cyclopentadienyl ring structures being a substituted cyclopentadienyl group which provides an orientation with respect to said transition metal atom which is sterically different from the orientation of the other cyclopentadienyl group with respect to said transition metal atom, both of said cyclopentadienyl groups being in a relationship with each other providing a stereorigid relationship relative to said coordinating transition metal atom to prevent rotation of said ring structures; c) said metallocene ligand structure having a kinetic diameter which is less than the average effective pore size of said silica and said metallocene being preferentially located within the interior pore volume of said silica particles to provide at least 50% of the polymerization sites provided on said transition metal atom being within the interior pore volume of said support; and d) an aluminum containing cocatalyst incorporated into said particulate silica support wherein said aluminum-containing cocatalyst is incorporated predominantly within the interior pore volume of said particulate support.