Homogeneous-heterogeneous catalyst system for polyolefins

A catalyst system for the polymerization of olefins comprising a combination of at least one homogeneous catalyst and at least one heterogeneous catalyst wherein the homogeneous catalyst is a metallocene catalyst comprising a) a neutral metallocene of the general formula R".sub.b (C.sub.p Rphd 4pl )(C.sub.p R'.sub.4)MR.sup.*.sub.v-2 where R" is a bridge imparting stereorignidityto the structure to the metallocene by connecting the two cyclopentadienyl rings, b is 0 or 1, Cp is a cyclopentadienyl ring, R and R' are substituents on the cyclopentadienyl rings and can be a hydride or a hydrocarbyl from 1-9 carbon atoms, each R and R' being the same or different, each (CpR.sub.4) and (CpR'.sub.4) being the same or different, M is a Group IIIB, IVB, VB or VIB metal, R.sup.* is a hydride, a halogen or a hydrocarbyl from 1-20 carbon atoms, v is the valence of M and b) an ionizing agent which will ionize a neutral metallocene compound to form a cationic metallocene catalyst wherein the heterogeneous is a conventional Ziegler-Natta transition metal compound catalyst comprising: a) a transition metal of the general formula MR.sup.+.sub.x where M is a Group IIIB, IVB, VB or VIB metal, R.sup.+ is a halogen or a hydrocarboxyl and x is the valence of the metal and b) an aluminum alkyl of the general formula AlR.sup.#.sub.3 where R.sup.# is an alkyl of from 1-8 carbon atoms and R.sup.# may be the same or different.