Patents by Inventor Derek Stewart Hunter Smith

Derek Stewart Hunter Smith 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 the control of microbial contamination in water-based solids suspensions
    Patent number: 6503449
    Abstract: The present invention relates to a process for the elimination of microbial contamination from water-based suspensions of solid particles, especially organic and inorganic pigment dispersions, and the colourant formulations containing such suspensions.
    Type: Grant
    Filed: March 29, 2001
    Date of Patent: January 7, 2003
    Assignee: Ciba Specialty Chemicals Corporation
    Inventor: Derek Stewart Hunter Smith
  • Process for the preparation of pigment compositions
    Patent number: 6361595
    Abstract: Preparation of stabilized pigment compositions, comprising mixing a water-miscible quaternary ammonium compound of formula III wherein R1, R2, R3 and R4 independently of each other stand for C1-C22aklyl, C2-C22alkenyl, benzyl, pyridyl, quinolyl, isoquinolyl or polyoxyalkylenyl, and X− is an anion, a water-immiscible organic solvent and a pigment.
    Type: Grant
    Filed: April 10, 2000
    Date of Patent: March 26, 2002
    Assignee: Ciba Specialty Chemicals Corporation
    Inventor: Derek Stewart Hunter Smith