Patents by Inventor Walter Heyer

Walter Heyer 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).

  • 2,2-Bis[4-(2,3-dibromopropoxy)-3,5-dibromophenyl]-propane process
    Patent number: 4302614
    Abstract: 2,2-Bis[4-(2,3-dibromopropoxy)-3,5-dibromophenyl]-propane (BDDP) has the structural formula ##STR1## This bisphenol-A derivative is prepared by reaction of 2,2-bis[4-hydroxy-3,5-dibromophenyl]-propane with an allyl halide and subsequent bromination of the diallyl ether obtained. In the first reaction step, a lower aliphatic alcohol is used as solvent, and in the second reaction step an aromatic halogenated hydrocarbon. The reaction product is then precipitated by excess alcohol, and separated. The BDDP is obtained in the form of granules and is suitable for application as flameproofing agent.
    Type: Grant
    Filed: February 11, 1980
    Date of Patent: November 24, 1981
    Assignee: Riedel-de Haen Aktiengesellschaft
    Inventors: Wolfgang Dannenberg, Walter Heyer, Theo Doldissen, Manfred Zimmermann