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 comprising a substantially light-insensitive organic silver salt, an organic reducing agent therefor in thermal working relationship therewith, at least one binder and at least one stabilizer represented by formula (I):

wherein R 1 , R 2 , R 3 and R 4 are independently selected from the group consisting of a hydrogen atom, halogen atoms and aliphatic, alkoxy, nitro, acyl, sulfonyl, nitrile, alkaryl, aryl, amino, thioalkyl, aldehyde, urea, —O—(C═O)-alkyl, —O—(C═O)-aryl, —O—(C═O)—O—alkyl, —O—(C═O)—O-aryl, —NH—(C═O)-alkyl, —NH—(C═O)-aryl, —(C═O)—NH-alkyl, —(C═O)—NH—aryl, —NH—(SO 2 )-alkyl, —NH—(SO 2 )-aryl, —(SO 2 )—NH-alkyl, —(SO 2 )—NH-aryl groups: X is —A—M: A is selected from the group consisting of substituted aliphatic groups, unsubstituted aliphatic groups, substituted cycloaliphatic groups, unsubstituted cycloaliphatic groups, substituted aromatic groups and unsubstituted aromatic groups where in each of said groups one or more of the chain or ring carbon atoms may be substituted by one or more atoms selected from the group consisting of S, O, Si, N and P atoms: and -M is a substituted or unsubstituted group selected from the group consisting of a -(2-S-imidazole) group and a -(2-S-imidazole) group annelated with an aromatic ring system, the optional substituents for -M being selected from the group consisting of halogen atoms and aliphatic, alkoxy, nitro, acyl, sulfonyl, nitrite, alkaryl and aryl groups.

2. 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, at least one binder and at least one stabilizer represented by formula (I):

wherein R 1 , R 2 , R 3 and R 4 are independently selected from the group consisting of a hydrogen atom, halogen atoms and aliphatic, alkoxy, nitro, acyl, sulfonyl, nitrile, alkaryl, aryl, amino, thioalkyl, aldehyde, urea, —O—(C═O)-alkyl, —O—(C═O)-aryl, —O—(C═O)—O-alkyl, —O—(C═O)—O—aryl, —NH—(C═O)-alkyl, —NH—(C═O)-aryl, —(C═O)—NH—alkyl, —(C═O)—NH—aryl, —NH—(SO 2 )-alkyl, —NH—(SO 2 )-aryl, —(SO 2 )-NH-alkyl, —(SO 2 )-NH-aryl groups: X is -A-(CH 2 ) m -M m is 2 to 20: A is selected from the group consisting of substituted aliphatic groups, unsubstituted aliphatic groups, substituted cycloaliphatic groups, unsubstituted cycloaliphatic groups, substituted aromatic groups and unsubstituted aromatic groups where in each of said groups one or more of the chain or ring carbon atoms may be substituted by one or more atoms selected from the group consisting of S, O, Si, N and P atoms; and -M is a substituted or unsubstituted group selected from the group consisting of a -(2-S-imidazole) group and a -(2-S-imidazole) group annelated with an aromatic ring system, the optional substituents for -M being selected from the group consisting of halogen atoms and aliphatic, alkoxy, nitro, acyl, sulfonyl, nitrile, alkaryl and aryl groups.

3. 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, at least one binder and at least one stabilizer represented by formula (I):

wherein R 1 , R 2 , R 3 and R 4 are independently selected from the group consisting of a hydrogen atom, halogen atoms and aliphatic, alkoxy, nitro, acyl, sulfonyl, nitrile, alkaryl, aryl, amino, thioalkyl, aldehyde, urea, —O—(C═O)-alkyl, —O—(C═O)-aryl, —O—(C═O)—O—alkyl, —O—(C═O)—O-aryl, —NH—(C═O)-alkyl, —NH—(C═O)-aryl, —(C═O)—NH-alkyl, —(C═O)—NH—aryl, —NH—(SO 2 )-alkyl, —NH-(SO 2 )-aryl, —(SO 2 )-NH-alkyl, —(SO 2 )-NH-aryl groups; X is -A-(CH 2 ) m -M; m is 4 to 9; A is selected from the group consisting of substituted aliphatic groups, unsubstituted aliphatic groups, substituted cycloaliphatic groups, unsubstituted cycloaliphatic groups, substituted aromatic groups and unsubstituted aromatic groups where in each of said groups one or more of the chain or ring carbon atoms may be substituted by one or more atoms selected from the group consisting of S, O, Si, N and P atoms; and -M is a substituted or unsubstituted group selected from the group consisting of a -(2-S-imidazole) group and a -(2-S-imidazole) group annelated with an aromatic ring system, the optional substituents for -M being selected from the group consisting of halogen atoms and aliphatic, alkoxy, nitro, acyl, sulfonyl, nitrile, alkaryl and aryl groups.

4. 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, at least one binder and at least one stabilizer is selected from the group consisting of:

5. 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, at least one binder and at least one stabilizer is selected from the group consisting of:

6. The substantially light-insensitive black and white monosheet thermographic recording material according to claim 1 , wherein said at least one binder comprises at least one first polymer consisting of vinyl aceto-acetal monomer units and monomer units selected from the group consisting of vinyl butyral, vinyl alcohol, vinyl acetate and itaconic acid monomer units, wherein the weight ratio of said at least one binder to said substantially light-insensitive organic silver salt in said thermosensitive element is greater than 1.5; and said at least one binder optionally contains less than 40% by weight of a second polymer consisting of vinyl butyral monomer units and optionally vinyl alcohol and/or vinyl acetate monomer units.

7. The substantially light-insensitive black and white monosheet thermographic recording material according to claim 1 , wherein said thermosensitive element further contains an optionally substituted benzotriazole.

8. 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, at least one binder and at least one stabilizer represented by formula (I):

wherein R 1 , R 2 , R 3 and R 4 are independently selected from the group consisting of a hydrogen atom, halogen atoms and aliphatic, alkoxy, nitro, acyl, nitrile, alkaryl, aryl, amino, thioalkyl, aldehyde, urea, —O—(C═O)-alkyl, —O—(C═O)-aryl, —O—(C═O)—O-alkyl, —O—(C═O)—O—aryl, —NH—(C═O)-alkyl, —NH—(C═O)-aryl, —(C═O)—NH-alkyl, —(C═O)—NH-aryl, —NH—(SO 2 )-alkyl, —NH—(SO 2 )-aryl, —(SO 2 )-NH-alkyl, —(SO 2 )-NH-aryl groups; X is represented by -A(-M) m or is selected from the group consisting of substituted aliphatic groups, unsubstituted aliphatic groups, substituted cycloaliphatic groups, unsubstituted cycloaliphatic groups, substituted aromatic groups and unsubstituted aromatic groups where in each of said groups one or more of the chain or ring carbon atoms may be substituted by one of more atoms selected from the group consisting of S, O, Si, N and P atoms; n is 2, 3 or 4; A is selected from the group consisting of substituted aliphatic groups, unsubstituted aliphatic groups, substituted cycloaliphatic groups, unsubstituted cycloaliphatic groups, substituted aromatic groups and unsubstituted aromatic groups where in each of said groups one or more of the chain or ring carbon atoms may be substituted by one of more atoms selected from the group consisting of S, O, Si, N and P atoms; each (-M) is independently a substituted or unsubstituted group selected from the group consisting of -(2-S-imidazole) groups and -(2-S-imidazole) groups annelated with an aromatic ring system, the optional substituents for -M being selected from the group consisting of halogen atoms and aliphatic, alkoxy, nitro, acyl, sulfonyl, nitrile, alkaryl and aryl groups.

9. The substantially light-insensitive black and white monosheet thermographic recording material according to claim 8 , wherein A is selected from the group consisting of an optionally substituted alkyl groups, optionally substituted alkenyl groups, optionally substituted alkynyl groups, optionally substituted alkyaryl groups, optionally substituted alkyl-heterocyclic groups, optionally substituted alkyl-heteroaromatic groups, optionally substituted alkyl groups in which at least one of the non-terminal main chain carbon atoms is substituted with an oxygen or a sulfur atom, optionally substituted aryl groups, optionally substituted alkyl-aryl-alkyl groups, optionally substituted alkyl-heteroaryl-alkyl groups, optionally substituted alkyl-COO-alkyl-OOC-alkyl groups, optionally substituted alkyl-O—COO-alkyl groups, optionally substituted alkyl-CONH-alkyl groups, and optionally substituted alkyl-COO-aryl-OOC-alkyl groups.

10. The substantially light-insensitive black and white monosheet thermographic recording material according to claim 8 , wherein in said at least one stabilizer according to formula (I) X is -A-M and -M is a -(2-S-imidazole) group or a (2-S-imidazole) group annelated with an aromatic ring system.

11. The substantially light-insensitive black and white monosheet thermographic recording material according to claim 8 , wherein in said at least one stabilizer according to formula (I) X is -A-(CH 2 ) m -M, wherein m is 2 to 20 and -M is a (2-S-imidazole) group or a -(2-S-imidazole) group annelated with an aromatic ring system.

12. The substantially light-insensitive black and white monosheet thermographic recording material according to claim 8 , wherein in said at least one stabilizer according to formula (I) X is -A-(CH 2 ) m -M, wherein m is 4 to 9 and -M is a (2-S-imidazole) group or a (2-S-imidazole) group annelated with an aromatic ring system.

13. The substantially light-insensitive black and white monosheet thermographic recording material according to claim 8 , wherein said at least one stabilizer is selected from the group consisting of:

14. The substantially light-insensitive black and white monosheet thermographic recording material according to claim 8 , wherein said at least one stabilizer is selected from the group consisting of:

15. The substantially light-insensitive black and white monosheet thermographic recording material according to claim 8 , wherein said at least one binder comprises at least one first polymer consisting of vinyl aceto-acetal monomer units and monomer units selected from the group consisting of vinyl butyral, vinyl alcohol, vinyl acetate and itaconic acid monomer units, wherein the weight ratio of said at least one binder to said substantially light-insensitive organic silver salt in said thermosensitive element is greater than 1.5; and said at least one binder optionally contains less than 40% by weight of a second polymer consisting of vinyl butyral monomer units and optionally vinyl alcohol and/or vinyl acetate monomer units.

16. The substantially light-insensitive black and white monosheet thermographic recording material according to claim 8 , wherein said thermosensitive element further contains an optionally substituted benzotriazole.

17. The substantially light-insensitive black and white monosheet thermographic recording material according to claim 2 , wherein said at least one binder comprises at least one first polymer consisting of vinyl aceto-acetal monomer units and monomer units selected from the group consisting of vinyl butyral, vinyl alcohol, vinyl acetate and itaconic acid monomer units, wherein the weight ratio of said at least one binder to said substantially light-insensitive organic silver salt in said thermosensitive element is greater than 1.5; and said at least one binder optionally contains less than 40% by weight of a second polymer consisting of vinyl butyral monomer units and optionally vinyl alcohol and/or vinyl acetate monomer units.

18. The substantially light-insensitive black and white monosheet thermographic recording material according to claim 2 , wherein said thermosensitive element further contains an optionally substituted benzotriazole.

19. The substantially light-insensitive black and white monosheet thermographic recording material according to claim 3 , wherein said at least one binder comprises at least one first polymer consisting of vinyl aceto-acetal monomer units and monomer units selected from the group consisting of vinyl butyral, vinyl alcohol, vinyl acetate and itaconic acid monomer units, wherein the weight ratio of said at least one binder to said substantially light-insensitive organic silver salt in said thermosensitive element is greater than 1.5; and said at least one binder optionally contains less than 40% by weight of a second polymer consisting of vinyl butyral monomer units and optionally vinyl alcohol and/or vinyl acetate monomer units.

20. The substantially light-insensitive black and white monosheet thermographic recording material according to claim 3 , wherein said thermosensitive element further contains an optionally substituted benzotriazole.

21. The substantially light-insensitive black and white monosheet thermographic recording material according to claim 4 , wherein said at least one binder comprises at least one first polymer consisting of vinyl aceto-acetal monomer units and monomer units selected from the group consisting of vinyl butyral, vinyl alcohol, vinyl acetate and itaconic acid monomer units, wherein the weight ratio of said at least one binder to said substantially light-insensitive organic silver salt in said thermosensitive element is greater than 1.5; and said at least one binder optionally contains less than 40% by weight of a second polymer consisting of vinyl butyral monomer units and optionally vinyl alcohol and/or vinyl acetate monomer units.

22. The substantially light-insensitive black and white monosheet thermographic recording material according to claim 4 , wherein said thermosensitive element further contains an optionally substituted benzotriazole.

23. The substantially light-insensitive black and white monosheet thermographic recording material according to claim 5 , wherein said at least one binder comprises at least one first polymer consisting of vinyl aceto-acetal monomer units and monomer units selected from the group consisting of vinyl butyral, vinyl alcohol, vinyl acetate and itaconic acid monomer units, wherein the weight ratio of said at least one binder to said substantially light-insensitive organic silver salt in said thermosensitive element is greater than 1.5; and said at least one binder optionally contains less than 40% by weight of a second polymer consisting of vinyl butyral monomer units and optionally vinyl alcohol and/or vinyl acetate monomer units.

24. The substantially light-insensitive black and white monosheet thermographic recording material according to claim 5 , wherein said thermosensitive element further contains an optionally substituted benzotriazole.