PREPARATION OF COATING FLUID FOR SECURITY PAPER SUCH AS POSTAGE STAMP AND REVENUE STAMP CONTAINING FLUORESCENT FUNCTIONAL PIGMENT AND SECURITY PAPER

摘要

PROBLEM TO BE SOLVED: To prevent the secondary flocculation of a functional pigment and to stabilize the quality of a coating fluid by putting a dispersant so as to disperse various pigments in water when the pigments are mixed. ;SOLUTION: Powder of a fluorescent functional pigment is put in an aqueous coating pigment solution prepared by mixing water, a dispersant and coating pigments, water is added, a thickener is put, water is added, an adhesive is put and they are agitated to obtain the objective coating fluid. When the coating pigments are first mixed, the dispersant is put so as to disperse the pigments in the water. This dispersant prevents the secondary flocculation of the fluorescent functional pigment even though the pigment is put as the powder. The most effective amount of the dispersant is 0.4-0.6 wt.% (expressed in terms of solid). The particle diameter of the fluorescent functional pigment is usually in the range of 1-3 μm but the most appropriate mixability and color developing property are ensured in the range of 1.7-2.3 μm.;COPYRIGHT: (C)2000,JPO