Patents by Inventor David Roy Witzke

David Roy Witzke 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).

  • Impact modified melt-stable lactide polymer compositions and processes for manufacture thereof
    Patent number: 6495631
    Abstract: The invention is directed toward melt-processable lactide polymer compositions, processes for manufacturing these compositions, and articles made from these compositions. The compositions include a first phase, which contains a polylactide-based polymer, and a second phase which includes elastomer. The elastomer is present in an amount sufficient to provide a polymer composition having an impact resistance of at least about 0.7 ft-lb/in. after the melt-processable polymer composition has been injection molded into bars and tested according to ASTM D256 (1993) method C. Preferably, the compositions also include a reactive compatibilizing agent. Methods of making these compositions and articles made from these compositions are also disclosed.
    Type: Grant
    Filed: April 12, 1999
    Date of Patent: December 17, 2002
    Assignee: Cargill, Incorporated
    Inventors: Jed Richard Randall, Christopher Michael Ryan, James Lunt, Mark Henry Hartman, Eric Stanley Hall, Jeffrey John Kolstad, David Roy Witzke
  • Viscosity-modified lactide polymer composition and process for manufacture thereof
    Patent number: 6291597
    Abstract: A composition comprising a polylactide polymer with improved extensional viscosity and methods of making the same are disclosed. The polylactide polymer composition is prepared by providing in the composition polylactide polymer molecules which have been modified, relative to linear non-substituted polylactide, to provide increased molecular interaction among polylactide backbone chains in the composition. The preferred polylactide polymer composition has a number average molecular weight of at least about 10,000 (preferably at least 50,000) and a polydispersity of at least about 2.5. In addition, the polylactide polymer composition should have a neck-in ratio of less than about 0.8.
    Type: Grant
    Filed: September 20, 1999
    Date of Patent: September 18, 2001
    Assignee: Cargill, Incorporated
    Inventors: Patrick Richard Gruber, Jeffrey John Kolstad, David Roy Witzke, Mark Henry Hartmann, Andrea Lee Brosch
  • Viscosity-modified lactide polymer composition and process for manufacture thereof
    Patent number: 5998552
    Abstract: A composition comprising a polylactide polymer with improved extensional viscosity and methods of making the same are disclosed. The polylactide polymer composition is prepared by providing in the composition polylactide polymer molecules which have been modified, relative to linear non-substituted polylactide, to provide increased molecular interaction among polylactide backbone chains in the composition. The preferred polylactide polymer composition has a number average molecular weight of at least about 10,000 (preferably at least 50,000) and a polydispersity of at least about 2.5. In addition, the polylactide polymer composition should have a neck-in ratio of less than about 0.8.
    Type: Grant
    Filed: July 20, 1998
    Date of Patent: December 7, 1999
    Assignee: Cargill, Incorporated
    Inventors: Patrick Richard Gruber, Jeffrey John Kolstad, David Roy Witzke, Mark Henry Hartmann, Andrea Lee Brosch
  • Impact modified melt-stable lactide polymer compositions and processes for manufacture thereof
    Patent number: 5922832
    Abstract: The invention is directed toward melt-processable lactide polymer compositions, processes for manufacturing these compositions, and articles made from these compositions. The compositions include a first phase, which contains a polylactide-based polymer, and a second phase which includes elastomer. The elastomer is present in an amount sufficient to provide a polymer composition having an impact resistance of at least about 0.7 ft-lb/in. after the melt-processable polymer composition has been injection molded into bars and tested according to ASTM D256 (1993) method C. Preferably, the compositions also include a reactive compatibilizing agent. Methods of making these compositions and articles made from these compositions are also disclosed.
    Type: Grant
    Filed: October 27, 1997
    Date of Patent: July 13, 1999
    Assignee: Cargill, Incorporated
    Inventors: Jed Richard Randall, Christopher Michael Ryan, James Lunt, Mark Henry Hartman, Eric Stanley Hall, Jeffrey John Kolstad, David Roy Witzke
  • Viscosity-modified lactide polymer composition and process for manufacture thereof
    Patent number: 5798435
    Abstract: A composition comprising a polylactide polymer with improved extensional viscosity and methods of making the same are disclosed. The polylactide polymer composition is prepared by providing in the composition polylactide polymer molecules which have been modified, relative to linear non-substituted polylactide, to provide increased molecular interaction among polylactide backbone chains in the composition. The preferred polylactide polymer composition has a number average molecular weight of at least about 10,000 (preferably at least 50,000) and a polydispersity of at least about 2.5. In addition, the polylactide polymer composition should have a neck-in ratio of less than about 0.8.
    Type: Grant
    Filed: September 3, 1996
    Date of Patent: August 25, 1998
    Assignee: Cargill, Incorporated
    Inventors: Patrick Richard Gruber, Jeffrey John Kolstad, David Roy Witzke, Mark Henry Hartmann, Andrea Lee Brosch