Patents Examined by Scott L. Heatzog
  • Optically whitened clay pigments
    Patent number: 5587011
    Abstract: This invention involves a method of optically whitening clay minerals to transform their natural yellow tint to increased whiteness. Generally, it has been found that clay materials having low cation exchange capability can be directly reacted with very small amounts of cationic dyes, the apparent whiteness of said clay minerals being substantially increased thereby.
    Type: Grant
    Filed: April 6, 1995
    Date of Patent: December 24, 1996
    Assignee: J. M. Huber Corporation
    Inventors: Carl J. Marshall, Jr., Gary M. Freeman