| 摘要 |
Fluoran color former mixtures which contain at least (a) a fluoran compound of the formula <IMAGE> (1) (b) a fluoran compound of the formula <IMAGE> (2) in which R1, R3 and R4 are hydrogen, halogen, lower alkyl or lower alkoxy, R2 is halogen, lower alkyl or lower alkoxy, X1, X2, Y1 and Y2 are hydrogen, unsubstituted or halogen, hydroxyl, cyano or (lower alkoxy)-substituted alkyl, cycloalkyl, aryl or aralkyl, X3 and Y3 are hydrogen, unsubstituted or halogen-hydroxyl-, cyano- or (lower alkoxy)-substituted alkyl, cycloalkyl, aryl or aralkyl, X4 and Y4 are unsubstituted or halogen-, hydroxyl-, cyano- or (lower alkoxy)-substituted alkyl, cycloalkyl or aralkyl or (X1 and X2), (X3 and X4), (Y1 and Y2) and Y3 and Y4) are each, together with the shared nitrogen atom, a five- or six-membered heterocyclic radical and the rings A and B are substituted or unsubstituted, develop in recording systems deep and stable colorings and are suitable in particular for black recordings.
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