| abstract |
A bimodal polymerization catalyst system comprising: a non-metallocene olefin polymerization catalyst; and a zirconocene catalyst of Formula I: **(See formula)** (Formula I) where R4 is independently a C1 to C20 alkyl, aryl or aralkyl group or a hydrogen, where R3 is a C1 to C20 alkyl group , aryl, or aralkyl, and where each X is independently a halide, C1 to C20 alkyl group, aralkyl, or hydrogen, and where: R1 and R2 of Formula I, together with the carbon atoms to which they are attached, form a cycloalkyl group. |