Patents by Inventor Robert S. Steffanson

Robert S. Steffanson 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).

  • Non-solvent precipitation of polymer composition
    Patent number: 4182850
    Abstract: Production of polycarbonate or phenolphthalein polycarbonate copolymers and method for recovery of solid copolymer from solution.
    Type: Grant
    Filed: December 19, 1977
    Date of Patent: January 8, 1980
    Assignee: The Dow Chemical Company
    Inventors: Cary S. Marshall, Robert S. Steffanson