Thermographic recording materials containing a mesionic, 1,2,4-triazolium-3-thiolate compound

1. A substantially light-insensitive black and white monosheet thermographic recording material comprising a support and a thermosensitive element, said thermosensitive element comprising a substantially light-insensitive organic silver salt, an organic reducing agent therefor in thermal working relationship therewith, a binder and at least one mesionic 1,2,4-triazolium-3-thiolate compound.

2. The thermographic recording material according to claim 1 , wherein said mesionic 1,2,4-triazolium-3-thiolate compound is represented by formula (I):

wherein R 1 and R 3 are independently an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaromatic, amido, carboxy, carboxy ester or acyl group; R 2 is a hydrogen or an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaromatic, alkoxy, thioalkoxy, carboxy, amido, carboxy ester, acyl, carbonato or carbonatoalkyl group; or R 1 and R 2 or R 2 and R 3 represent the atoms needed to close an optionally substituted heterocyclic ring.

3. The thermographic recording material according to claim 2 , wherein said alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heterocyclic and hetroaromatic groups of R 1 , R 2 and R 3 are independently optionally substituted with fluorine atoms or an aryl, aryloxy, alkoxy, thioalkoxy, amido, carbonato, carbonatoalkyl, hydroxy, amino, carboxy or carboxyester group.

4. The thermographic recording material according to claim 2 , wherein R 1 and R 3 are independently an alkyl group, an alkyl group substituted with a carboxyester group, an alkenyl, or an aryl group; R 3 is a C 1 -C 3 alkyl group; and R 1 , R 2 and R 3 are not all methyl groups.

5. The thermographic recording material according to claim 1 , wherein said mesionic 1,2,4-triazolium-3-thiolate compound is

6. The thermographic recording material according to claim 1 , wherein said mesionic 1,2,4-triazolium-3-thiolate compound is

7. The thermographic recording material according to claim 1 , wherein said mesionic 1,2,4-triazolium-3-thiolate compound is

8. The thermographic recording material according to claim 1 , wherein said mesionic 1,2,4-triazolium-3-thiolate compound is

9. The thermographic recording material according to claim 1 , wherein said mesionic 1,2,4-triazolium-3-thiolate compound is

10. The thermographic recording material according to claim 1 , wherein said mesionic 1,2,4-triazolium-3-thiolate compound is

11. A process comprising the steps of: i) providing a substantially light-insensitive black and white monosheet thermographic recording material comprising a support and a thermosensitive element, said thermosensitive element comprising a substantially light-insensitive organic silver salt, an organic reducing agent therefor in thermal working relationship therewith, a binder and said at least one mesionic 1,2,4-triazolium-3-thiolate compound; and ii) image-wise heating said substantially light-insensitive black and white monosheet thermographic recording material, wherein the ratio of maximum optical density to the coverage of said substantially light-insensitive organic silver salt in g/m 2 is greater than the ratio of maximum optical density to the coverage of said substantially light-insensitive organic silver salt in g/m 2 said substantially light-insensitive black and white monosheet thermographic recording material in the absence of said at least one mesionic 1,2,4-triazolium-3-thiolate compound.