Patents Assigned to Riedel-De-Haen
  • Bipyridyls and their use as inks
    Patent number: 5266700
    Abstract: Process employing bipyridyls as inks, of the general formula ##STR1## in which R, R' are, for example, alkyl and R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6 are, for example hydrogen or alkyl radicals, or R.sup.1 and R.sup.2 or R.sup.2 and R.sup.3, and/or R.sup.4 and R.sup.5 or R.sup.5 and R.sup.6 together with the pyridine ring form in isoquinoline or quinoline ring system.
    Type: Grant
    Filed: December 31, 1991
    Date of Patent: November 30, 1993
    Assignee: Riedel-De-Haen
    Inventors: Heinz Langhals, Christoph Naumann