Patents by Inventor David B. Griffith

David B. Griffith 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).

  • Continuous process for producing poly(trimethylene terephthalate)
    Patent number: 6353062
    Abstract: A continuous process for the production of poly(trimethylene terephthalate) is disclosed. According to the process, a liquid feed mixture comprising bis-3-hydroxypropyl terephthalate and/or low molecular weight polyesters of 1,3-propanediol and terephthalic acid, the liquid feed mixture having a mole ratio of propylene groups to terephthalate groups of 1.1 to 2.2 is fed to a prepolymerizer. Bis-3-hydroxypropyl terephthalate and the low molecular weight polyesters are continuously polymerized to form a poly(trimethylene terephthalate) prepolymer and a first stream of gaseous by-products. Poly(trimethylene terephthalate) prepolymer having a relative viscosity of at least about 5 is continuously withdrawn from the prepolymerizer and continuously fed to a final polymerizer, where it is continuously polymerized to form a higher molecular weight poly(trimethylene terephthalate) and a second stream of gaseous by-products.
    Type: Grant
    Filed: February 11, 2000
    Date of Patent: March 5, 2002
    Assignee: E. I. du pont de Nemours and Company
    Inventors: Carl J. Giardino, David B. Griffith, Chungfah Howard Ho, James M. Howell, Michelle Hoyt Watkins, Joseph James Duffy
  • Method and composition for odor control
    Patent number: 5984993
    Abstract: A method and composition are provided for controlling odor from waste products. The composition comprises a combination of chlorite salt and nitrate salt. The method includes the step of contacting the waste products or their surrounding airspace with the composition.
    Type: Grant
    Filed: March 20, 1998
    Date of Patent: November 16, 1999
    Assignee: Vulcan Materials Company
    Inventors: Eric L. Mainz, David B. Griffith