Patents by Inventor Holger Conzelmann

Holger Conzelmann 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 preparing polyisocyanates
    Patent number: 10112892
    Abstract: The present invention relates to a continuous process for preparing a polyisocyanate, in which a polyamine and phosgene are first converted predominantly to carbamoyl chloride and amine hydrochloride and only in minor proportions to polyisocyanate, and a portion of the carbamoyl chloride- and amine hydrochloride-containing reaction mixture thus obtained is recycled into the reaction with phosgene, wherein polyamine, phosgene and the carbamoyl chloride- and amine hydrochloride-containing reaction mixture are mixed intimately in a mixing unit. The portion of the carbamoyl chloride- and amine hydrochloride-containing reaction mixture which is not recycled into the phosgenation is worked up to give the polyisocyanate.
    Type: Grant
    Filed: June 27, 2016
    Date of Patent: October 30, 2018
    Assignee: Covestro Deutschland AG
    Inventors: Jürgen Arras, Jan Busch, Christian Steffens, Dietmar Wastian, Manfred Keller-Killewald, Holger Conzelmann
  • PROCESS FOR PREPARING POLYISOCYANATES
    Publication number: 20180179150
    Abstract: The present invention relates to a continuous process for preparing a polyisocyanate, in which a polyamine and phosgene are first converted predominantly to carbamoyl chloride and amine hydrochloride and only in minor proportions to polyisocyanate, and a portion of the carbamoyl chloride- and amine hydrochloride-containing reaction mixture thus obtained is recycled into the reaction with phosgene, wherein polyamine, phosgene and the carbamoyl chloride- and amine hydrochloride-containing reaction mixture are mixed intimately in a mixing unit. The portion of the carbamoyl chloride- and amine hydrochloride-containing reaction mixture which is not recycled into the phosgenation is worked up to give the polyisocyanate.
    Type: Application
    Filed: June 27, 2016
    Publication date: June 28, 2018
    Inventors: Jürgen Arras, Jan Busch, Christian Steffens, Dietmar Wastian, Manfred Keller-Killewald, Holger Conzelmann