Thermal base precursors
AssigneeEastman Kodak Company
InventorsRamanuj Goswami, Wojciech K. Slusarek, David H. Levy
Life of this patent
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Abstract
Improved compounds and base precursors that undergo thermal decomposition are disclosed. Thermal base precursors, and in particular, a novel class of salts of arylsulfonylacetic acids as bleaching agents or promoting for photothermographic use are disclosed. Compositions employing these thermal base precursors are suitable for use in acutance and antihalation systems, bleachable filter dye materials, and in promoting unblocking of various components such as blocked developers, especially in photothermographic elements.
Claims25
A composition comprising a base precursor that is the salt of an organic base with an arylsulfonylacetic acid having the following structure:
- wherein the group R1 represents a substituted or unsubstituted alkyl group, cycloalkyl group, aralkyl group, aryl group or heterocyclic group;
- each of R2 and R3 is independently a monovalent group;
- said base precursor being further in association with a filter dye;
- wherein the organic base is a diacidic to tetraacidic base having the following Structure;
- R13(—B)n
- wherein R13 is an n-valent residue of a hydrocarbon or heterocyclic ring, each of which may have one or more substituent groups;
- “n” is an integer of 2 to 4;
- and wherein “B” is a monovalent group corresponding to an atomic group formed by removing one hydrogen atom from an guanidine having the Structure;
- wherein each of R14, R15, R16, R17 and R18 are independently a hydrogen, an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, an aralkyl group, an aryl group and a heterocyclic group, wherein each of R14, R15, R16, R17 and R18 may have one or more substituent groups;
- or any two of R14, R15, R16, R17 and R18 may by combined together to form a five-membered or six-membered nitrogen containing heterocyclic ring;
- wherein base precursor is capable of bleaching the filter dye, thereby forming a composition that is useful as a thermally bleachable dye composition, wherein said arylsulfonylacetic acid undergoes decarboxylation at a temperature of 50 to 200° C. and will form a carbanion that is capable of abstracting a hydrogen from the organic base, rendering the organic base effective as a bleaching agent for said dye.
A photothermographic element comprising a support having thereon at least one light-sensitive imaging layer and at least one layer comprising an effective amount of a base precursor comprising the salt of an organic base with an arylsulfonylacetic acid having the following structure:
- wherein the group R1 represents a substituted or unsubstituted alkyl group cycloalkyl group, aralkyl group, aryl group or heterocyclic group;
- each of R2 and R3 is independently a monovalent group;
- said base precursor being further in bleaching association with a filter dye;
- wherein the organic base is a diacidic to tetraacidic base having the following Structure;
- R13(—B)n
- wherein R13 is an n-valent residue of a hydrocarbon or heterocyclic ring, each of which may have one or more substituent groups;
- “n” is an integer of 2 to 4;
- and wherein “B” is a monovalent group corresponding to an atomic group formed by removing one hydrogen atom from an guanidine having the Structure;
- wherein each of R14, R15, R16, R17 and R18 are independently a hydrogen, an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, an aralkyl group, an aryl group and a heterocyclic group, wherein each of R14, R15, R16, R17 and R18 may have one or more substituent groups;
- or any two of R14, R15, R16, R17 and R18 may by combined together to form a five-membered or six-membered nitrogen containing heterocyclic ring;
- wherein said filter dye that becomes at least about 50% colorless within about 5 minutes upon heating to a temperature of at least about 90° C.
Dependencies are inferred from the claim text.