Patents Examined by D. G. Daus
  • Perylenetetracarboxylic acid diimides and their use
    Patent number: 4446324
    Abstract: Novel perylene-3,4,9,10-tetracarboxylic acid diimides of the formula ##STR1## where R.sup.1 and R.sup.2 are each isopropyl or R.sup.1 is methyl or ethyl and R.sup.2 is C.sub.3 - or C.sub.4 -alkyl, give clear, luminous, very lightfast, fluorescent orange colorations in plastics.The dyes are particularly suitable for concentrating light.
    Type: Grant
    Filed: December 9, 1981
    Date of Patent: May 1, 1984
    Assignee: BASF Aktiengesellschaft
    Inventor: Fritz Graser