Stabilized leuco phenazine dyes and their use in an imaging system
AssigneeMinnesota Mining and Manufacturing Company
InventorAlan G. Miller
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Abstract
3,7-Diamino phenazine leuco dyes stabilized in the 10-position with acyl substituents, said acyl substituents being themselves substituted with electron withdrawing groups. These dyes are suitable for use in thermographic imaging systems wherein the leuco dye is in a composition containing a nitrate salt.
Claims11
A thermally imageable layer consisting essentially of a binder, at least one leuco dye, and a nitrate salt, wherein the action of heat can oxidize said at least one leuco dye to give a change in color, wherein said at least one leuco dye has the structural formula ##STR47## wherein R.sup.1 represents an aryl group having at least one electron-withdrawing substituent thereon or an alkyl group having at least one electron-withdrawing substituent thereon;
- R.sup.2 represents a member selected from the group consisting of unsubstituted and substituted alkyl groups, and unsubstituted and substituted aryl groups;
- R.sup.3, R.sup.4, R.sup.5 and R.sup.6 independently represent members selected from the group consisting of hydrogen, substituted and unsubstituted alkyl groups, and ##STR48## where R.sup.7 represents an unsubstituted or substituted aryl group or an unsubstituted or substituted alkyl group;
- and
- R.sup.8, R.sup.9, R.sup.10, R.sup.11, R.sup.12, and R.sup.13 independently represent members of the group selected from hydrogen, halogens, unsubstituted alkyl groups, substituted alkyl groups, unsubstituted alkoxy groups, and substituted alkoxy groups.
Dependencies are inferred from the claim text.