Equistar Makes Large Run of New Single-Site HDPE.

Equistar Chemicals LP in Houston has made the first commercial-scale run of polyethylene based on its new STAR single-site catalyst technology at its slurry-loop plant in Clinton, Iowa. The new catalysts reportedly allow fine-tuning of molecular-weight distribution, melt index, density, and long-chain branching. Designated Petrothene LTTR39O, the new material is a narrow-MWD, 1.0 MI, 0.958 g/cc HDPE for blown film. It reportedly offers an excellent balance of clarity; impact strength, and tear resistance (see table). Moreover, it boasts excellent extrudability and bubble stability; resulting in very uniform film. It has been shown to process very similarly to conventional MMW HDPE, even though its MWD is much narrower--around 2.5 Mw/Mn (similar to the range for metallocene PE), versus 6.9 to 10.5 for Ziegler-Natta HDPE.

Large sample quantities are available for evaluation. Food packaging appears to be among the most promising application areas. Full commercial production is likely by the end of the first quarter of 2001. By mid-year, Equistar also plans to start commercial trials of a STAR-based MDPE (0.940 g/cc) for film and rotomolding and a 0.915 g/cc LLDPE blown-film resin.