Patents by Inventor Hellmut Trautwein

Hellmut Trautwein 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 the production of oxymethylene copolymer molding compositions with a low content of residual formaldehyde
    Patent number: 4225703
    Abstract: Oxymethylene copolymers molding compositions with low portions of residual formaldehyde are produced by heating the polymerizate melts treated with chemical stabilizers in an apparatus in which there are continuously presented new polymerizate surfaces under reduced pressure. The heating of the polymerizate melt takes place in a thin layer evaporator for highly viscous media during an average residence time of 30 to 120 seconds at an average rate of shear between 500 and 2000 s.sup.-1 and at a pressure P.sub.abs of at most 150 mbar. The escaping gases and vapors are drawn off countercurrent to the polymerizate melt.
    Type: Grant
    Filed: September 11, 1979
    Date of Patent: September 30, 1980
    Assignee: Deutsche Gold- und Silber-Scheideanstalt vormals Roessler
    Inventors: Herbert Amann, Gerhard Morlock, Hellmut Trautwein