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.
The pressure-sensitive copy system of claim 1 wherein said chromogenic compound has the formula
Claim 2
Dependent Claim
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The pressure-sensitive copy system of claim 1 wherein R represents a C1-C5 lower alkyl group.
Claim 3
Dependent Claim
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The pressure-sensitive copy system of claim 3 wherein X and Y represent hydrogen and n is 0, said compound being 7,7''-bis(3-diethylaminofluoran).
Claim 4
Dependent Claim
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The pressure-sensitive copy system of claIm 3 wherein X represents hydrogen, Y represents a methyl group, and n is 0, said compound being 7,7''-bis(3-diethylamino-6-methylfluoran).
Claim 5
Dependent Claim
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The pressure-sensitive copy system of claim 3 wherein X and Y each represent hydrogen, Z is a methylene group and n is 1, said compound being 7,7''-methylene-bis(3-diethylaminofluoran).
Claim 6
Dependent Claim
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The pressure-sensitive copy system of claim 3 wherein said microcapsules additionally contain at least one blue imaging chromogenic compound.
Claim 7
Dependent Claim
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The pressure-sensitive copy system of claim 7 wherein the said microcapsules contain Crystal Violet Lactone and Benzoyl Leuco Methylene Blue.
Claim 8
Dependent Claim
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The pressure-sensitive copy system of claim 8 wherein said microcapsules additionally contain an isomeric mixture of cis 3, 5- and trans 3,7-bis(3'' ,6''-dimethoxy-9''-spiroxanthyl)pyromellitide.