Stabilizers for use in substantially light-insensitive thermographic recording materials

1. A substantially light-insensitive black and white monosheet thermographic recording material comprising a support and a thermosensitive element, said thermosensitive element containing a substantially light-insensitive organic silver salt, an organic reducing agent therefor in thermal working relationship therewith, a binder and at least one stabilizer selected from the group consisting of 1-(5-mercapto-1-tetrazolyl)-acetyl compounds represented by formula (I):

wherein R 1 is —NR 2 R 3 , —OR 4 or an optionally substituted aryl or heteroaryl group; R 2 is hydrogen or an optionally substituted alkyl, aryl or heteroaryl group; R 3 is an optionally substituted aryl or heteroaryl group; and R 4 is an optionally substituted aryl group; and compounds with two or more groups represented by formula (II):

where Q comprises the necessary atoms to form a 5- or 6-membered unsaturated heterocyclic ring, A is hydrogen, a counterion to compensate the negative charge of the thiolate group or two or more A groups provide a linking group between the two or more groups represented by formula (II).

2. Substantially light-insensitive black and white monosheet thermographic recording material according to claim 1 , wherein at least one of said 5- or 6-membered unsaturated heterocyclic rings is a pyridine, a pyrazine, a pyrimidine, a triazine, a pyrrole, a 1,2,3-triazole, a 1,2,4-triazole, a tetrazole, an oxadiazole, a thiadiazole, an oxazole, an iso-oxazole, a thiazole, an iso-thiazole or an imidazole ring.

3. Substantially light-insensitive black and white monosheet thermographic recording material according to claim 1 , wherein the at least one compound according to formula (II) is represented by formula (III):

(X 1 ) n (X 2 ) m (X 3 ) p (X 4 ) q L  (III)

wherein L is a linking group linking the one or more X 1 , X 2 , X 3 and X 4 groups; X 1 , X 2 and X 3 are independently

n, m, p and q are independently 0, 1, 2, 3 or 4; n+m+p+q=2, 3 or 4; R 5 and R 6 are independently hydrogen, alkyl, aryl, acyl, —NR 7 R 8 , —SR 9 or —S-A; R 7 and R 8 are independently hydrogen or an alkyl or acyl group; R 9 is an alkyl group; and A has the same meaning as in formula (II).

4. Substantially light-insensitive black and white monosheet thermographic recording material according to claim 1 , wherein said at least one compound according to formula (II) is represented by formula (IV):

wherein R 5 has the same meaning as in formula (III); the two R 5 groups may be the same or different; and L 1 is a linking group.

5. Substantially light-insensitive black and white monosheet thermographic recording material according to claim 1 , wherein said at least one compound according to formula (II) is represented by formula (IV):

wherein R 6 has the same meaning as in formula (III); the two R 6 groups may be the same or different; and L 2 is a linking group.

6. Substantially light-insensitive black and white monosheet thermographic recording material according to claim 1 , wherein said at least one compound according to formula (II) is represented by formula (VI):

wherein A has the same meaning as in formula (II) and L 4 is a linking group.

7. Substantially light-insensitive black and white monosheet thermographic recording material according to claim 1 , wherein said at least one stabilizer is:

8. Substantially light-intsensitive black and white monosheet thermographic recording material according to claim 1 , wherein said at least one stabilizer is:

9. Substantially light-insensitive black and white monosheet thermographic recording material according to claim 1 , wherein said at least one stabilizer is:

10. Substantially light-insensitive black and white monosheet thermographic recording material according to claim 1 , wherein said thermosensitive element further comprises an optionally substituted benzotriazole.