Patents by Inventor Jaak Van Steen

Jaak Van Steen 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 manufacture of 4,4'-diphenyl-methane diisocyanate and a mixture of diphenyl-methane diisocyanate isomers containing a small amount of uretdiones and hydrolyzable chlorine
    Patent number: 4294666
    Abstract: A process for the manufacture of 4,4'-diphenylmethane diisocyanate and a mixture of diphenylmethane diisocyanate isomers containing a controllable amount of uretdione and hydrolizable chlorine which comprises feeding crude MDI to an evaporator, condensing a head fraction in two stages in the presence of an inert gas, feeding the first stage condensate to a distillation column, producing a mixture of diphenylmethane diisocyanate isomers as an overhead, producing 4,4'-diphenylmethane diisocyanate as a side draw, and condensing each of the overhead and side draw in two stages in the presence of an inert gas.
    Type: Grant
    Filed: August 15, 1980
    Date of Patent: October 13, 1981
    Assignee: BASF Aktiengesellschaft
    Inventors: Hans J. Astheimer, Horst Brandtstaedter, Rainer Ohlinger, Willy Van Pee, Jaak Van Steen, Friedrich Sauer, Rudolf Schmidt, Siegfried Krueger