ExxonMobil & Basell Pool R&D on Metallocene PP.

ExxonMobil Chemical, Houston, and Basell in Wilmington, Del., are now combining their R&D on metallocene polypropylene into a single effort. They will share mPP knowhow and R&D, and each company will license the other to use its mPP patents. The partners will separately make and sell mPP resins.

Basell's roots in the technology date back to the 1986 mPP project of Hoechst, one of Basell's predecessor companies. Basell now markets Metocene mPP, primarily for injection molding. It can replace clear PS in items such as CD cases.

ExxonMobil was first in the industry to commercialize mPP in 1995. Its Achieve resins were initially focused on nonwoven fibers. Says worldwide PP product executive Dick Grabham, "We've been making a product with a fairly narrow molecular-weight distribution. The new catalyst we have developed will broaden the molecular weight and produce resins with a fractional MFR, similar to what can be made with conventional Ziegler-Natta catalysts." Resins made with this catalyst have high purity, very little atactic content, low acidity, and low chloride levels. They offer improved processing over Z-N PP, says Grabham.

ExxonMobil has sampled the new resins, which are made on a pilot scale using both Basell's Spheripol loop/gas-phase process and the Novalen gas-phase process that Basell sold to an Equistar joint venture. ExxonMobil's first commercial run with the new catalyst last month used a bulk liquid process from Sumitomo Chemical.

Full commercial availability is expected in 2002. Initial offerings will be homopolymers for film and injection molding that feature clarity, heat resistance, and good stiffness. Basell is also investigating mPP for blow molding and profile extrusion, as well as random copolymers for everything from film seal layers to auto parts.