Patents by Inventor Don R. Stevenson

Don R. Stevenson 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).

  • Phosphite ester additive composition
    Patent number: 6824711
    Abstract: The invention relates to a liquid polymer additive composition comprising at least one phosphite ester selected from the group consisting of aryl phosphites, alkyl phosphites, aryl/alkyl phosphites, bisphenol-A phosphites, dialkylene glycol phosphites and polydialkylene glycol phosphites, pentaerythritol phosphites, p-cumyl phenol phosphites and blends thereof and approximately from 50 to 800 ppm inclusive of zinc per 100 parts resin. The stabilizer is used as either a complete or a partial replacement of toxic-metal containing antioxidant stabilizer additives.
    Type: Grant
    Filed: March 1, 2002
    Date of Patent: November 30, 2004
    Assignee: Dover Chemical Corporation
    Inventors: Don R. Stevenson, Thomas C. Jennings, Mark E. Harr, Michael R. Jakupca
  • Blends of phosphites and antioxidants
    Patent number: 6770693
    Abstract: This invention discloses blends of phosphites comprising bis-(2,4-dicumylphenyl) pentaerythritol diphosphite and hindered phenol antioxidants useful as stabilizers against thermooxidative degradation of polymers during melt processing. Polymer compositions comprising the blends show improved resistance to thermooxidative degradation during melt processing as measured by melt flow index and yellowness index.
    Type: Grant
    Filed: September 25, 2001
    Date of Patent: August 3, 2004
    Assignee: Dove Chemical Corporation
    Inventors: Daryl Stein, Don R. Stevenson, Satyan R. Kodali, Marc Nolen
  • Phosphite ester additive compositions
    Publication number: 20030001136
    Abstract: The invention relates to a liquid polymer additive composition comprising at least one phosphite ester selected from the group consisting of aryl phosphites, alkyl phosphites, aryl/alkyl phosphites, bisphenol-A phosphites, dialkylene glycol phosphites and polydialkylene glycol phosphites, pentaerythritol phosphites, p-cumyl phenol phosphites and blends thereof and approximately from 50 to 800 ppm inclusive of zinc per 100 parts resin. The stabilizer is used as either a complete or a partial replacement of toxic-metal containing antioxidant stabilizer additives.
    Type: Application
    Filed: March 1, 2002
    Publication date: January 2, 2003
    Inventors: Don R. Stevenson, Thomas C. Jennings, Mark E. Harr, Michael R. Jakupca
  • Blends of phosphites and antioxidants
    Publication number: 20020040081
    Abstract: This invention discloses blends of phosphites comprising bis-(2,4-dicumylphenyl) pentaerythritol diphosphite and hindered phenol antioxidants useful as stabilizers against thermooxidative degradation of polymers during melt processing. Polymer compositions comprising the blends show improved resistance to thermooxidative degradation during melt processing as measured by melt flow index and yellowness index.
    Type: Application
    Filed: September 25, 2001
    Publication date: April 4, 2002
    Applicant: Dover Chemical
    Inventors: Daryl Stein, Don R. Stevenson, Satyan R. Kodali, Marc Nolen
  • Lactone/phosphite blends
    Patent number: 6224791
    Abstract: This invention discloses synergistic blends of phosphates and lactones having a base structure of 3-phenylbenzofuran-2-one with or without other additives as stabilizers for polymers, particularly during melt processing as evidenced by changes in melt flow and in some instances, resistance to yellowing.
    Type: Grant
    Filed: January 13, 2000
    Date of Patent: May 1, 2001
    Assignee: Dover Chemical Corporation
    Inventors: Don R. Stevenson, Daryl L. Stein