Patents by Inventor Jeff C. Stewart

Jeff C. Stewart 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).

  • Polymerization catalyst having a phosphinimine ligand
    Patent number: 6342463
    Abstract: This invention is a solution process for the preparation of high molecular weight ethylene copolymers comprising contacting olefin monomers, with a catalyst system at a polymerization temperature at or above about 80° C. with a catalyst system comprising an unbridged Group 4 metal compound having a monocyclopentadienyl ligand, a phosphinimine ligand and at least one uninegative, activation reactive ligand. The process can be practiced at a reaction temperature of at least 80° C. to obtain high number average molecular weight polymer.
    Type: Grant
    Filed: February 25, 2000
    Date of Patent: January 29, 2002
    Assignee: Nova Chemicals (International) S.A.
    Inventors: Douglas W. Stephan, Jeff C. Stewart, Stephen John Brown, John William Swabey, Qinyan Wang
  • High temperature solution polymerization process with phosphinimine cyclopentadienyl metal (GRP IV) complex
    Patent number: 6063879
    Abstract: This invention is a solution process for the preparation of high molecular weight ethylene copolymers comprising contacting olefin monomers, with a catalyst system at a polymerization temperature at or above about 80.degree. C. with a catalyst system comprising an unbridged Group 4 metal compound having a monocyclopentadienyl ligand, a phosphinimine ligand and at least one uninegative, activation reactive ligand. The process can be practiced at a reaction temperature of at least 80.degree. C. to obtain high number average molecular weight polymer.
    Type: Grant
    Filed: October 29, 1997
    Date of Patent: May 16, 2000
    Assignee: Nova Chemicals (International) S.A.
    Inventors: Douglas W. Stephan, Jeff C. Stewart, Stephen John Brown, John William Swabey, Qinyan Wang
  • Supported phosphinimine-Cp catalysts
    Patent number: 5965677
    Abstract: A catalyst component which is especially useful in so-called "slurry" or "gas phase" olefin polymerizations and which comprises an organometallic complex of a group 4 metal (having a cyclopentadienyl-type ligand and a phosphinimine ligand) and a particulate support. The catalyst component forms an excellent catalyst system when combined with an activator such as an aluminoxane or a so-called "substantially non-coordinating anion". In a preferred embodiment the organometallic complex and the activator are both deposited on the particulate support.
    Type: Grant
    Filed: October 29, 1997
    Date of Patent: October 12, 1999
    Assignee: Nova Chemicals (International) S.A.
    Inventors: Douglas W. Stephan, Jeff C. Stewart, Daryll G. Harrison