Mitsui Sekka producing metallocene PP in pilot

June 24, 1997 Mitsui Petrochemical Industries, Ltd. (Mitsui Sekka) has launched trial production of polypropylene (PP) using a metallocene asymmetric catalyst the company has developed. The firm claims the new catalyst process ensures very stable production of PP with a molecular weight distribution approaching the theoretical value.
Mitsui Sekka is the third in the world to develop a metallocene catalyst for PP, after Exxon Chemical and Hoechst.
The new PP is being produced at a pilot plant at the Iwakuni factory site of Grand Polymer Co., a 50-50 venture between Mitsui Sekka and Ube Industries, Ltd.
The major advantage of the new PP process is that it permits PP with a molecular weight distribution on the order of "2" to be produced on a stable basis; conventional PP has a very limited range of 4-8. The new process also controls the heat resistance, strength, and hardness of PP, and can adjust its properties to accommodate structural, packaging, fibre, or other materials.
The asymmetric catalyst developed by Mitsui Sekka is a zirconium-based metal complex with a metallocene structure combined with a ligand. The project is part of Mitsui Group's metallocene-process polymer scheme. Evolue Japan Co., owned 75 % by Mitsui Sekka and 25 % by Sumitomo Chemical, is scheduled to start operating a 200,000-tpy metallocene-process L-LDPE plant next spring. Mitsui Sekka is also preparing to commercialise a-olefin copolymer and EPDM using metallocene processes.

In related news, Mitsui Toatsu Chemicals, Inc., with which Mitsui Sekka is set to combine at October 1st, and Belgian Fina are formulating a syndiotactic polypropylene (SPP) production method using a metallocene catalyst. Upon successful development, the new Mitsui Chemical Co. will be able to offer a wider range of high-quality PP, from commodity to specialty types.