Patents by Inventor Willem Lodewijk Sederel

Willem Lodewijk Sederel 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 branched melt polycarbonate by late addition of fries-inducing catalyst
    Patent number: 6504002
    Abstract: The invention relates to a method for the production of a branched polycarbonate composition, having increased melt strength, by late addition of branch-inducing catalysts to the polycarbonate oligomer in a melt polycondensation process. Surprisingly, it has been found that by adding branch-inducing catalysts, such as alkali metal compounds and/ or alkaline earth metal compounds, to the melt polycarbonate oligomer at a later stage of the melt polycondensation process, preferably after the oligomer has reached an average molecular weight of between about 3,000 and 30,000 g/mole, a unique branched polycarbonate composition is formed that has improved properties. It is believed that the addition of the branch-inducing catalysts at the later stages of the process produces a branched polycarbonate composition having longer chains between the branching points, and thus a new composition is produced. The invention also relates to various applications of the branched polycarbonate composition.
    Type: Grant
    Filed: December 21, 2001
    Date of Patent: January 7, 2003
    Assignee: General Electric Company
    Inventors: Dennis Karlik, Hans Peter Brack, Hendrik Verhoogt, John Patrick Lemmon, Jan Henk Kamps, Willem Lodewijk Sederel, Johannes Martinus Dina Goossens