This is done by a two-stage Ziegler catalyst
polymerization in which each stage provides resins with different branching.
1) that a Ziegler catalyst
can polymerize isoprene to yield polyisoprene similar to that of natural rubber with a microstructure (99% cis 1,4) affording similar physical properties when compounded in tire tread recipes.
BP isn't the first to pursue mixed metallocene and Ziegler catalyst
Carbide also uses Ziegler catalyst
to make a narrow-MWD VLDPE similar to Dow's and Mitsui's.
Paper presented at the 40 years Ziegler catalysts
, Friburg, Germany, (1993) 427-439.
XM-series elastomers boast higher performance than Tafmer resin modifiers produced with Ziegler catalysts