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Catalyst system for the polymerization of alkenes to polyolefins

United States Patent

October 22, 2002
View the Complete Patent at the US Patent & Trademark Office
The invention provides metallocene catalyst systems for the controlled polymerization of alkenes to a wide variety of polyolefins and olefin coplymers. Catalyst systems are provided that specifically produce isotactic, syndiotactic and steroblock polyolefins. The type of polymer produced can be controlled by varying the catalyst system, specifically by varying the ligand substituents. Such catalyst systems are particularly useful for the polymerization of polypropylene to give elastomeric polypropylenes. The invention also provides novel elastomeric polypropylene polymers characterized by dyad (m) tacticities of about 55% to about 65%, pentad (mmmm) tacticities of about 25% to about 35%, molecular weights (M.sub.w)in the range of about 50,000 to about 2,000,000, and have mmrm+rrmr peak is less than about 5%.
Miller; Stephen A. (Cambridge, MA), Bercaw; John E. (Pasadena, CA)
California Institute of Technology (Pasadena, CA)
09/ 488,431
January 20, 2000
GOVERNMENT SUPPORT The government may have certain rights in this invention pursuant to Grant No. DE-FG03-88ER13431 from the Department of Energy.