Patents by Inventor Michael Dierolf

Michael Dierolf 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 using nitric acid to oxidize polyarylene sulfide to polyarylene sulfoxide
    Patent number: 6369172
    Abstract: The invention relates to a process for using nitric acid to oxidize polyarylene sulfide to polyarylene sulfoxide, oxidizing at least 98% of the sulfide groups of the polyarylene sulfide to sulfoxide groups. According to the invention polyarylene sulfide is treated with nitric acid at a concentration of from 60 to 80% with heating. The polyarylene sulfoxide prepared by the novel process can be used as an excellent chemical blowing agent for foaming thermoplastics.
    Type: Grant
    Filed: April 12, 2000
    Date of Patent: April 9, 2002
    Assignee: Ticona GmbH
    Inventors: Dirk Zierer, Helmut Scheckenbach, Michael Dierolf