MPC Mitsui Petrochemical
MPC Mitsui Petrochemical : A continuous process for polymerizing propylene, based on the Ziegler-Natta process, but using a much more active catalyst so that de-ashing (catalyst removal) is not required. The catalyst contains magnesium in addition to titanium; successive versions of it have been known as HY-HS (high yield, high stereospecifity), HY-HS II, and T-catalyst