Patents by Inventor Li Ja

Li Ja has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Metallocene catalyst containing bulky organic group
    Patent number: 5502017
    Abstract: An ionic metallocene catalyst for olefin polymerization which comprises: (1) a cyclopentadienyl-type ligand, a Group IVB transition metal, and alkyl, aryl, or hydride substituents, as a cation, and (2) a weakly coordinating anion comprising boron substituted with halogenated, such as tetra fluoro, aryl substituents preferably containing silylalkyl substitution, such as para-silyl t-butyldimethyl.
    Type: Grant
    Filed: March 10, 1994
    Date of Patent: March 26, 1996
    Assignee: Northwestern University
    Inventors: Tobin J. Marks, Li Ja, Xinmin Yang
  • Sterically shielded diboron-containing metallocene olefin polymerization catalysts
    Patent number: 5447895
    Abstract: A non-coordinating anion, preferably containing a sterically shielded diboron hydride, if combined with a cyclopenta-dienyl-substituted metallocene cation component, such as a zirconocene metallocene, is a useful olefin polymerization catalyst component. The anion preferably has the formula ##STR1## where R is branched lower alkyl, such as t-butyl.
    Type: Grant
    Filed: March 10, 1994
    Date of Patent: September 5, 1995
    Assignee: Northwestern University
    Inventors: Tobin J. Marks, Li Ja, Xinmin Yang