Patents Assigned to Faber-Castell
  • Fluorescent marking liquid
    Patent number: 5084327
    Abstract: A new fluorescent aqueous marking liquid is described, which contains 0.20 to 2.0 % by weight of cumarin C.J. Basic Yellow 40 dye. The liquid is buffered to a pH value of from 3 to 5; it contains an acrylic resin dispersion at a pH of 3 to 5 with a particle agglomerate of 35 to 150 nm. The liquid does not act on a third dye, especially triphenylmethane dye, which is used frequently in carbon paper and is used also on smooth surfaces such as glass plastic foil or glazing paper.
    Type: Grant
    Filed: December 18, 1989
    Date of Patent: January 28, 1992
    Assignee: Faber-Castell
    Inventor: Rudolf Stengel