Process and catalyst for producing poly-ethylene having a broad molecular weight distribution

Claim 1

A process for producing polyethylene which comprises polymerising ethylene in the presence of a catalyst system comprising (a) a common alumoxane as a cocatalyst component and (b1) a catalytic amount of a first metallocene having first propagation and termination rate constants suitable for providing, with such alumoxane, a polymer having a narrow MWD with an Mw at a first value; and (b2) a catalytic amount of a second metallocene having second propagation and termination rate constants different from the first and suitable for providing, with such alumoxane a polymer having a narrow, MWD with an Mw at a second value different from the first value, said metallocenes being mono, di or tricyclopentadienyl derivatives of a Group 4b, 5b or 6b transition metal and the respective different metallocenes being used as transition metal catalyst component in proportions selected such as to provide a desired broad or multimodal MWD in conjunction with one another.