Triphenylmethane, acid strength

Standard cyan ink-jet dyes are C.I. Acid Blue 9, 42090 [3844-45-9] and C.I. DirectBlue 199, 74190 [12222-04-7], C.I. Acid Blue 9 is characterized by a superior brilliancy of shade and high color strength, but this triphenylmethane dye exhibits a low lightfastness. Copper phthalocyanine dye C.I. DirectBlue 199 is suited for many applications due to its superior lightfastness and thermal stability. To improve its moderate waterfastness on plain paper, novel cyan dyes have been launched based on the differential solubility approach by introducing carboxyl groups into the phthalocyanine moiety [3,12],... 

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