Patents by Inventor William G. Bradford

William G. Bradford 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).

  • Polymer solution treatment process
    Patent number: 5244965
    Abstract: The present invention provides a process to remove phosphine residues from a hydrogenated polymer solution.
    Type: Grant
    Filed: June 14, 1989
    Date of Patent: September 14, 1993
    Assignee: Polysar Limited
    Inventors: Akhtar Osman, William G. Bradford
  • Process for removing rhodium-containing catalyst residue from hydrogenated nitrile rubber
    Patent number: 4985540
    Abstract: A process is provided for removing rhodium-containing catalyst residue from a solution of hydrogenated nitrile rubber. The process utilizes an ion exchange resin which must be both macroreticular and modified with a selected amine, thiol, carbodithioate, thiourea and/or dithiocarbamate functional group. The process is capable of removing rhodium from viscous rubber solutions containing less than 10 ppm rhodium. In a preferred embodiment, the process is undertaken in an ion-exchange column.
    Type: Grant
    Filed: November 20, 1989
    Date of Patent: January 15, 1991
    Assignee: Polysar Limited
    Inventors: William G. Bradford, Gilles J. Arsenault, Alexander J. Marshall
  • Method to treat rhodium-containing solutions
    Patent number: 4944926
    Abstract: The present invention provides a method to treat a rhodium containing solution which is derived from the catalytic hydrogenation of nitrile rubber.An additive selected from thiourea, polysaccharide and carbon black is used to cause a rhodium-containing precipitate. The precipitate is then separated from the solution by, for example, filtration or centrifugation.
    Type: Grant
    Filed: August 1, 1988
    Date of Patent: July 31, 1990
    Assignee: Polysar Limited
    Inventors: Akhtar Osman, William G. Bradford