Patents by Inventor John M. Downer

John M. Downer 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).

  • Tetrafluoroethylene polymers
    Patent number: 4129618
    Abstract: A tetrafluoroethylene polymer comprising primary particles having core and shell portions, the core portion comprising tetrafluoroethylene polymerised in the presence of a perfluoroalkyl or alkoxy trifluoro-ethylene comonomer, particularly hexafluoropropylene, and shell portion consisting of tetrafluoroethylene homopolymer, or a copolymer of tetrafluoroethylene in which the comonomer concentration is less than half that in the core portion.
    Type: Grant
    Filed: December 30, 1976
    Date of Patent: December 12, 1978
    Assignee: Imperial Chemical Industries Limited
    Inventors: John M. Downer, William G. Rodway, Lawrence S. J. Shipp