| abstract |
A substantially colorless bisfluoran chromogenic material having the structural formula WHEREIN R1 and R2 each represent an alkyl group; X and Y each represent a hydrogen atom, a halogen atom, an hydroxyl group, an alkyl group, a nitro group, an amino group, an acyl group, or a carboalkoxy group; Z represents an oxy radical, a carbonyl group, an alkylene group, an alkylidene group, a sulfonyl group, or a thio radical; and N REPRESENTS AN INTEGER FROM 0 TO 1. The bisfluoran compounds are produced by reacting a 4dialkylamino-2-hydroxy-2''-carboxybenzophenone with a diphenol wherein the diphenol is unsubstituted in at least one of the positions ortho to an hydroxyl group in each of the phenyl rings. The bisfluorans are used in pressure-sensitive copy systems comprising a support bearing microcapsules containing the bisfluorans, alone, or in combination with other color-forming materials. |