US 5,330,864 AGranted

Cyan chromogenic leuco dyes for photothermographic materials

AssigneeMinnesota Mining and Manufacturing Company

InventorsRaffaella Biavasco, Cristina Soncini

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Abstract

Phothermographic material capable of producing a high density cyan image upon image-wise exposure and thermal development at a relatively low temperature and for a short period of time. The photothermographic material of the invention comprise coated on a support base at least one light-sensitive emulsion layer containing: (a) a binder; (b) a silver source material; (c) a light sensitive silver halide in catalytic proximity to said silver source material, wherein said emulsion layer or an adjacent layer thereto comprises a chromogenic cyan leuco dye. The photothermographic material of the invention may be used to obtain good cyan image of suitable density in single color or multicolor photothermographic articles. At the same time the chromogenic leuco dye is stable enough not to be oxidized by oxygen of the air or by simple heating and to limit the fog formation after development.

Claims14

Dependent claims

A photothermographic material capable of producing a high density cyan image upon imagewise exposure and thermal development comprising coated on a support base at least one light-sensitive emulsion layer containing:

(a) a binder;
(b) a silver source material;
(c) a light sensitive silver halide in catalytic proximity to said silver source material, wherein said emulsion layer or an adjacent layer thereto comprises a chromogenic cyan leuco dye represented by the general formula:
##STR12## wherein R.sub.1 is a --CONH--R.sub.8 group, a --CO--R.sub.8 group or a --CO--O--R.sub.8 group, R.sub.8 being an alkyl group or an aryl group;
R.sub.2 is a hydrogen atom or a short alkyl group;
R.sub.3 and R.sub.4 may be the same or different including a hydrogen atom, a short alkyl group, a --X--Y group, wherein X is a short alkylene group and Y is a cyano group, a halogen atom, --OH or --NHSO.sub.2 --Z group, wherein Z is an alkyl group;
R.sub.5 independently is a hydrogen atom, a halogen atom, an alkyl group, or a --NHCO--R group, wherein R is an alkyl group or an aryl group, and R.sub.6 independently is a hydrogen atom, a halogen atom, an alkyl group, or an alkoxy group;
or R.sub.5 and R.sub.6 can combine to form a benzene ring or a heterocyclic ring;
R' is a hydrogen atom or is A--R.sub.7, wherein A is a --NCHO-- group, a -- CONH-- group, or a --NHCONH-- group, and R.sub.7 is an alkyl group or an aryl group, W is a hydrogen atom or a group as described for R.sub.1.

6 more elements

(Amended) A photothermographic material capable of producing a high density cyan image upon image-wise exposure and thermal development comprising coated on a support base at least one light-sensitive emulsion layer containing:

(a) a binder;
(b) a silver source material;
(c) a light sensitive silver halide in catalytic proximity to said silver source material, wherein said emulsion layer or an adjacent layer thereto comprises a chromogenic cyan leuco dye represented by the general formula:
##STR15## wherein R.sub.2 is a hydrogen atom or a short alkyl group;
R.sub.3 and R.sub.4 can be the same or different, each including a hydrogen atom, a short alkyl group, an --X--Y group, wherein X is a short alkylene group and Y is a cyano group, a halogen atom, --OH or --NHSO.sub.2 --Z group, where Z is an alkyl group;
R.sub.5 independently is a hydrogen atom, a halogen atom, an alkyl group, or a --NHCO--R group, wherein R is an alkyl group or an aryl group, and R.sub.6 independently is a hydrogen atom, a halogen atom, an alkyl group, or an alkoxy group;
or R.sub.5 and R.sub.6 can combine to form a benzene ring or a heterocyclic ring;
R' is a hydrogen atom or is A-R.sub.7, wherein A is a --NCHO-- group, a --CONH-- group, or a --NHCONH-- group, and R.sub.7 is an alkyl group or an aryl group;
R.sub.8 is an alkyl group or an aryl group;
Q is --NH-- or --O--;
W is a hydrogen atom or a --CONH--R.sub.8, --CO--R.sub.8 or --CO--O--R.sub.8 group and n is 0 or 1.

8 more elements

Dependencies are inferred from the claim text.