Security paper contg. reactive fluorescent colourant - selected from pyrene:sulphonic acids and salts, used for making payment or official documents

摘要

Security paper, used esp. for making payment and official documents allowing no alternation of characters, contains on its surface and/or in the body of the paper, a reactive fluorescent colourant selected from pyrenesulphonic acids and their metallic, pref. alkali(ne earth) metal salts. The colourant is compatible with the usual solns. or dispersions impregnated or printed onto the paper and immediately fluoresce under the action of ink remover and alkaline agents. It is not removed by prolonged washing. Pref. the pyrenesulphonic acid is of formula (I) (where X1-X4 are H, SO3H, OH or NR1R2, R1 and R2 are H or 1-4C alkyl, 1 of X1-X4 being SO3H, X5 is H or 1-4C alkyl and may be present in any of the rings of the molecule.