Storage stable blue writing ink contg. a triphenyl methane dye - in acid soln. and an aromatic sulphonic and or hydroxycarboxylic acid

摘要

Writing ink contains a triphenyl methane dyestuff in aq. acid soln. together with an aromatic sulphonic acid and/or an aromatic hydroxycarboxylic acid. The (blue) ink is completely storage-stable and requires no preservatives. The colour strength and brilliance is also improved. Specifically the ink contains in aq. soln. 0.5-2%, esp. 1% dyestuff which is pref. in its easily sol. ammonium salt form; and 0.1-2% of the aromatic acid and opt. an inorganic acid to obtain the desired optimum pH of 1.5-3, esp. 2-2.5.