Patents by Inventor John Michael Downer

John Michael 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).

  • Process for aqueous dispersion of perfluoroalkyl- or perfluoroalkoxy trifluoroethylene polymers
    Patent number: 4038231
    Abstract: A tetrafluoroethylene polymer comprising primary particles having core and shell portions, the core portion comprising tetrafluoroethylene polymerized in the presence of a perfluoroalkyl or alkoxy trifluoroethylene 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: September 30, 1974
    Date of Patent: July 26, 1977
    Assignee: Imperial Chemical Industries Limited
    Inventors: John Michael Downer, William George Rodway, Laurence Stanley John Shipp
  • Extrusion powder
    Patent number: 3951930
    Abstract: A tetrafluoroethylene polymer or copolymer suitable e.g. for extrusion on to wire to give an insulated conductor is produced using a dual catalyst system. The first catalyst component is a catalyst giving a high molecular weight (low SSG) such as ammonium persulphate (APS). The second component is a dibasic acid peroxide e.g. disuccinic acid peroxide (DSAP) which is added after the polymerisation has reached 20% conversion. The latter catalyst is found to produce a copolymer powder which can be extruded on to wire to give faultfree coating.
    Type: Grant
    Filed: September 17, 1974
    Date of Patent: April 20, 1976
    Assignee: Imperial Chemical Industries Limited
    Inventors: John Michael Downer, Colin Greig Kinnear