Thermal imaging methods and materials
AssigneePolaroid Corporation
InventorsRoger A. Boggs, Richard L. Cournoyer, Ernest W. Ellis, Sandra E. Russo-Rodriguez, Stephen J. Telfer, David P. Waller, Michael J. Zuraw
Life of this patent
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Abstract
Leuco dyes are provided which comprise the coupling product of a N-acyl substituted aromatic amino color developer and a dye-forming coupler moiety substituted at the coupling carbon with a thermally removable leaving group. Thermal imaging systems employing these leuco dyes have the advantage of reduced bubble formation relative to thermal imaging systems employing prior art leuco dyes containing a group which thermally fragments into one or more gases.
Claims28
A compound represented by ##STR26## wherein:
- E represents a thermally removable leaving group;
- tM represents a thermally migratable acyl group;
- Q, Q' and C taken together represent a dye-forming coupler moiety wherein C is the coupling carbon of said coupler moiety;
- and, (Y) taken together with N represents an aromatic amino color developer moiety,
- one of said Q, Q' and (Y) containing an atom selected from the atoms comprising Group 5A/Group 6A of the Periodic Table.
A compound having the structural formula ##STR31## wherein R.sup.4 is a t-butyl group or other group having a quaternary carbon atom bonded to the ketone carbonyl function;
- R.sup.5 is phenyl, unsubstituted or substituted with one or more groups selected from alkyl, alkoxy, nitro, halo, and carbonamido;
- E is a thermally removable leaving group;
- tM is a thermally migratable acyl group;
- and R.sup.6 and R.sup.7 are selected from hydrogen and lower alkyl groups containing 1 to 6 carbon atoms.
A compound having structural formula ##STR32## wherein tM represents a thermally migratable acyl group.
A dye represented by ##STR33## wherein:
- tM represents a thermally migratable acyl group;
- Q, Q' and C taken together represent a dye-forming coupler moiety wherein C is the coupling carbon of said coupler moiety;
- and, (Y) taken together with N represents an aromatic amino color developer moiety,
- one of said Q, Q' and (Y) containing an atom selected from the atoms comprising Group 5A/Group 6A of the Periodic Table, and said dotted lines indicate that said group tM is bonded to said Group 5A/Group 6A atom in one of said Q, Q' and (Y).
A dye having the structural formula ##STR38## wherein R.sup.4 is a t-butyl group or other group having a quaternary carbon atom bonded to the ketone carbonyl function;
- R.sup.5 is phenyl, unsubstituted or substituted with one or more groups selected from alkyl, alkoxy, nitro, halo, and carbonamido;
- tM is a thermally migratable acyl group;
- and R.sup.6 and R.sup.7 are selected from hydrogen and lower alkyl groups containing 1 to 6 carbon atoms.
Dependencies are inferred from the claim text.