Patents Assigned to Dequssa Aktiengesellschaft
  • Patent number: 5541284
    Abstract: The subject invention relates to method for processing crude polyoxymethylene in which the isolation of unstable components from crude polyoxymethylene, such as residual monomers which are at least partly in the form of cyclic formaldehyde derivatives, is effected by treatment of the crude polyoxymethylene with an inert gaseous medium. The method of the invention is characterized in that the gaseous medium contains at least 10 volume % of water vapor, and less than 0.1 volume % of a volatile base, and/or less than 1 volume % of a volatile solvent. In an alternative variant method, the gaseous medium contains at least 10 volume % of water vapor and the treatment occurs at a temperature between 114.degree. C and the softening temperature of the crude polyoxymethylene and at a pressure of less 1.2 .multidot.10.sup.5 Pa.
    Type: Grant
    Filed: March 20, 1995
    Date of Patent: July 30, 1996
    Assignee: Dequssa Aktiengesellschaft
    Inventors: Detlef Arnoldi, Udo Gropp, Edwin Nun
  • Patent number: 4402802
    Abstract: There is described an electrolytic bath for the deposition of haze-free glossy rhodium coatings which furnish a white gold-like tint and low tension flims. This bath in addition to rhodium sulfate or phosphate, sulfuric acid and/or phosphoric acid also contains a sulfonic acid, especially an aromatic sulfonic acid, as for example, phenolsulfonic acid.
    Type: Grant
    Filed: January 15, 1982
    Date of Patent: September 6, 1983
    Assignee: Dequssa Aktiengesellschaft
    Inventors: Erika Kreuter, Werner Kuhn, Wolfgang Zilske