Heat-sensitive lithographic printing plate precursor

1. A positive-working heat-sensitive lithographic printing plate precursor comprising a support having a hydrophilic surface or which is provided with a hydrophilic layer and an oleophilic coating provided on the support, said coating comprising an infrared light-to-heat converter and an alkali-soluble phenolic resin, wherein the phenyl group of the phenolic monomeric unit of said phenolic resin is

(a) chemically modified with an organic substituent comprising a group having the chemical structure of Formula I:

wherein n is 0, 1, 2 or 3,

wherein each R 1 is selected from hydrogen, an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group, —SO 2 —NH—R 2 , —NH—SO 2 —R 4 , —CO—NR 2 —R 3 , —NR 2 —CO—R 4 , —O—CO—R 4 , —CO—O—R 2 , —CO—R 2 , —SO 3 —R 2 , —SO 2 —R 2 , —SO—R 4 , —P(═O)(—O—R 2 )—(—O—R 3 ), —NR 2 —R 3 , —O—R 2 , —S—R 2 , —CN, —NO 2 , a halogen, —N-phthalimidyl, —M—N-phthalimidyl, or —M—R 2 , wherein M represents a divalent linking group containing 1 to 8 carbon atoms,

wherein R 2 , R 3 , R 5 and R 6 are independently selected from hydrogen or an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group,

wherein R 4 is selected from an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group,

or wherein at least two groups selected from each R 1 to R 4 together represent the necessary atoms to form a cyclic structure,

or wherein R 5 and R 6 together represent the necessary atoms to form a cyclic structure,

or

(b) substituted with a group having the structure —N═N—O, wherein the —N═N— group is covalently bound to a carbon atom of the phenyl group and wherein O is an aromatic group,

wherein said coating further comprises a polymeric development accelerator, and wherein said polymeric development accelerator is a phenolic formaldehyde resin comprising at least 70 mol % of meta-cresol as a recurring monomeric unit.

2. A positive-working heat-sensitive lithographic printing plate precursor comprising a support having a hydrophilic surface or which is provided with a hydrophiic layer and an oleophilic coating provided on the support, said coating comprising an infrared light-to-heat converter and an alkali-soluble phenolic resin, wherein the phenyl group of the phenolic monomeric unit of said phenolic resin is

(a) chemically modified with an organic substituent comprising a group having the chemical structure of Formula I:

wherein n is 0, 1, 2 or 3,

wherein each R 1 is selected from hydrogen, an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group, —SO 2 —NH—R 2 , —NH—SO 2 —R 4 , —CO—NR 2 —R 3 , —NR 2 —CO—R 4 , —O—CO—R 4 , —CO—O—R 2 , —CO—R 2 , —SO 3 —R 2 , —SO 2 —R 2 , —SO—R 4 , —P(═O)(—O—R 2 )(—O—R 3 ), —NR 2 —R 3 , —O—R 2 , —S—R 2 , —CN, —NO 2 , a halogen, —N-phthalimidyl, —M—N-phthalimidyl, or —M—R 2 , wherein M represents a divalent linking group containing 1 to 8 carbon atoms,

wherein R 2 , R 3 , R 5 and R 6 are independently selected from hydrogen or an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group,

wherein R 4 is selected from an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group,

or wherein at least two groups selected from each R 1 to R 4 together represent the necessary atoms to form a cyclic structure,

or wherein R 5 and R 6 together represent the necessary atoms to form a cyclic structure, or

(b) substituted with a group having the structure —N═N—O, wherein the —N═N— group is covalently bound to a carbon atom of the phenyl group and wherein O is an aromatic group,

wherein said coating further comprises a polymeric development accelerator, and wherein said polymeric development accelerator is a phenolic formaldehyde resin comprising at least 40 mol % of monohydroxy benzene as a recurring monomeric unit.

3. A positive-working heat-sensitive lithographic printing plate precursor comprising a support having a hydrophilic surface or which is provided with a hydrophilic layer and an oleophilic coating provided on the support, said coating comprising an infrared light-to-heat converter and an alkali-soluble phenolic resin, wherein the phenyl group of the phenolic monomeric unit of said phenolic resin is

(a) chemically modified with an organic substituent comprising a group having the chemical structure of Formula I:

wherein n is 0, 1, 2 , or 3,

wherein each R 1 is selected from hydrogen, an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group, —SO 2 —NH—R 2 , —NH—SO 2 —R 4 , —CO—NR 2 —R 3 , —NR 2 —CO—R 4 , —O—CO—R 4 , —CO—O—R 2 , —CO—R 2 , —SO 3 —R 2 , —SO 2 —R 2 , —SO—R 4 , —P(═O)(—O—R 2 )(—O—R 3 ), —NR 2 —R 3 , —O—R 2 , —S—R 2 , —CN, —NO 2 , a halogen, —N-phthalimidyl, —M—N-phthalimidyl, or —M—R 2 , wherein M represents a divalent linking group containing 1 to 8 carbon atoms,

wherein R 2 , R 3 , R 5 and R 6 are independently selected from hydrogen or an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group,

wherein R 4 is selected from an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group,

or wherein at least two groups selected from each R 1 to R 4 together represent the necessary atoms to form a cyclic structure,

or wherein R 5 and R 6 together represent the necessary atoms to form a cyclic structure,

or

(b) substituted with a group having the structure —N═N—O, wherein the —N═N— group is covalently bound to a carbon atom of the phenyl group and wherein O is an aromatic group,

wherein said coating further comprises a polymeric development accelerator, and wherein said polymeric development accelerator is a phenolic formaldehyde resin comprising at least 5 mol % of a recurring monomeric unit having at least one phenolic hydroxy group and at least one alkali solubilizing group.

4. A positive-working heat-sensitive lithographic printing plate precursor according to claim 3 , wherein said alkali solubilizing group is selected from the list consisting of a hydroxyl group, a carboxylic acid group, a sulphonic acid group, a sulphuric acid group, a phosphoric acid group, a phosphonic acid group and a thiol group.

5. A positive-working heat-sensitive lithographic printing plate precursor according to claim 3 , wherein said recurring monomeric unit has 2 or more phenolic hydroxyl groups.

6. A positive-working heat-sensitive lithographic printing plate precursor according to claim 5 , wherein said recurring monomeric unit is resorcinol, pyrocatechol, hydroquinone, hydroxy hydroquinone, pyrogallol, phloroglucinol or dihydroxy benzoic acid.

7. A lithographic printing plate precursor according to claim 1 wherein said coating further comprises a dissolution inhibitor.

8. A lithographic printing plate precursor according to claim 7 wherein said dissolution inhibitor is a water-repellent polymer.

9. A lithographic printing plate precursor according to claim 7 wherein said dissolution inhibitor is

a polymer comprising siloxane and/or perfluoroalkyl units; or

a block- or graft-copolymer of a poly(alkylene oxide) block and a block comprising siloxane and/or perfluoroalkyl units.

10. A lithographic printing plate precursor according to claim 7 wherein said dissolution inhibitor is an organic compound comprising an aromatic group and at least one hydrogen bonding site.

11. A method of making a heat-sensitive lithographic printing plate precursor according to claim 1 comprising the steps of

providing a support having a hydrophilic surface or which is provided with a hydrophilic layer; and

applying on said hydrophilic surface of said support an oleophilic coating, wherein said coating comprises an infrared light-to-heat converter, an alkali-soluble phenolic resin, wherein the phenyl group of the phenolic monomeric unit of said phenolic resin is

(a) chemically modified with an organic substituent comprising a group having the chemical structure of Formula I:

wherein n is 0, 1, 2 , or 3,

wherein each R 1 is selected from hydrogen, an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group, —SO 2 —NH—R 2 , —NH—SO 2 —R 4 , —CO—NR 2 —R 3 , —NR 2 —CO—R 4 , —O—CO—R 4 , —CO—O—R 2 , —CO—R 2 , —SO 3 —R 2 , —SO 2 —R 2 , —SO—R 4 , —P(═O)—(—O—R 2 )(—O—R 3 ), —NR 2 —R 3 , —O—R 2 , —S—R 2 , —CN, —NO 2 , a halogen, —N-phthalimidyl, —M—N-phthalimidyl, or —M—R 2 , wherein M represents a divalent linking group containing 1 to 8 carbon atoms,

wherein R 2 , R 3 , R 5 and R 6 are independently selected from hydrogen or an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group,

wherein R 4 is selected from an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group,

or wherein at least two groups selected from each R 1 to R 4 together represent the necessary atoms to form a cyclic structure,

or wherein R 5 and R 6 together represent the necessary atoms to form a cyclic structure,

or

(b) substituted with a group having the structure —N═N—O, wherein the —N═N— group is covalently bound to a carbon atom of the phenyl group and wherein O is an aromatic group,

wherein said coating further comprises a polymeric development accelerator, and wherein said polymeric development accelerator is a phenolic formaldehyde resin comprising at least 70 mol % of meta-cresol as a recurring monomeric unit.

12. A method of making a positive-working lithographic printing plate comprising the steps of

providing a heat-sensitive lithographic printing plate precursor according to claim 1 ,

image-wise exposing the coating to infrared light or heat, and

developing the image-wise exposed coating with an aqueous alkaline developer, wherein exposed areas of said coating dissolve in said aqueous alkaline developer.

13. A positive-working heat-sensitive lithographic printing plate precursor according to claim 1 , wherein O has the structure of formula I:

wherein n is 0, 1, 2 or 3,

wherein each R 1 is selected from hydrogen, an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group, —SO 2 —NH—R 2 , —NH—SO 2 —R 4 , —CO—NR 2 —R 3 , —NR 2 —CO—R 4 , —O—CO—R 4 , —CO—O—R 2 , —CO—R 2 , —SO 3 —R 2 , —SO 2 —R 2 , —SO—R 4 , —P(═O)(—O—R 2 )(—O—R 3 ), —NR 2 —R 3 , —O—R 2 , —S—R 2 , —CN, —NO 2 , a halogen, —N-phthalimidyl, —M—N-phthalimidyl, or —M—R 2 , wherein M represents a divalent linking group containing 1 to 8 carbon atoms,

wherein R 2 , R 3 , R 5 and R 6 are independently selected from hydrogen or an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group,

wherein R 4 is selected from an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group,

or wherein at least two groups selected from each R 1 to R 4 together represent the necessary atoms to form a cyclic structure,

or wherein R 5 and R 6 together represent the necessary atoms to form a cyclic structure.

14. A positive-working heat-sensitive lithographic printing plate precursor according to claim 2 wherein O has the structure of formula I:

wherein n is 0, 1, 2 or 3,

wherein each R 1 is selected from hydrogen, an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group, —SO 2 —NH—R 2 , —NH—SO 2 —R 4 , —CO—NR 2 —R 3 , —NR 2 —CO—R 4 , —O—CO—R 4 , —CO—O—R 2 , —CO—R 2 , —SO 3 —R 2 , —SO 2 —R 2 , —SO—R 4 , —P(═O)(—O—R 2 )(—O—R 3 ), —NR 2 —R 3 , —O—R 2 , —S—R 2 , —CN, —NO 2 , a halogen, —N-phthalimidyl, —M—N-phthalimidyl, or —M—R 2 , wherein M represents a divalent linking group containing 1 to 8 carbon atoms,

wherein R 2 , R 3 , R 5 and R 6 are independently selected from hydrogen or an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group,

wherein R 4 is selected from an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group,

or wherein at least two groups selected from each R 1 to R 4 together represent the necessary atoms to form a cyclic structure,

or wherein R 5 and R 6 together represent the necessary atoms to form a cyclic structure.

15. A positive-working heat-sensitive lithographic printing plate precursor according to claim 3 wherein O has the structure of formula I:

wherein n is 0, 1, 2 or 3,

wherein each R 1 is selected from hydrogen, an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group, —SO 2 —NH—R 2 , —NH—SO 2 —R 4 , —CO—NR 2 —R 3 , —NR 2 —CO—R 4 , —O—CO—R 4 , —CO—O—R 2 , —CO—R 2 , —SO 3 —R 2 , —SO 2 —R 2 , —SO—R 4 , —P(═O)(—O—R 2 )(—O—R 3 ), —NR 2 —R 3 , —O—R 2 , —S—R 2 , —CN, —NO 2 , a halogen, —N-phthalimidyl, —M—N-phthalimidyl, or —M—R 2 , wherein M represents a divalent linking group containing 1 to 8 carbon atoms,

wherein R 2 , R 3 , R 5 and R 6 are independently selected from hydrogen or an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group,

wherein R 4 is selected from an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group,

or wherein at least two groups selected from each R 1 to R 4 together represent the necessary atoms to form a cyclic structure,

or wherein R 5 and R 6 together represent the necessary atoms to form a cyclic structure.

16. A positive-working heat-sensitive lithographic printing plate precursor according to claim 4 wherein O has the structure of formula I:

wherein n is 0, 1, 2 or 3,

wherein each R 1 is selected from hydrogen, an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group, —SO 2 —NH—R 2 , —NH—SO 2 —R 4 , —CO—NR 2 —R 3 , —NR 2 —CO—R 4 , —O—CO—R 4 , —CO—O—R 2 , —CO—R 2 , —SO 3 —R 2 , —SO 2 —R 2 , —SO—R 4 , —P(═O)(—O—R 2 )(—O—R 3 ), —NR 2 —R 3 , —O—R 2 , —S—R 2 , —CN, —NO 2 , a halogen, —N-phthalimidyl, —M—N-phthalimidyl, or —M—R 2 , wherein M represents a divalent linking group containing 1 to 8 carbon atoms,

wherein R 2 , R 3 , R 5 and R 6 are independently selected from hydrogen or an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group,

wherein R 4 is selected from an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group,

or wherein at least two groups selected from each R 1 to R 4 together represent the necessary atoms to form a cyclic structure,

or wherein R 5 and R 6 together represent the necessary atoms to form a cyclic structure.

17. A positive-working heat-sensitive lithographic printing plate precursor according to claim 5 wherein O has the structure of formula I:

wherein n is 0, 1, 2 or 3,

wherein each R 1 is selected from hydrogen, an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group, —SO 2 —NH—R 2 , —NH—SO 2 —R 4 , —CO—NR 2 —R 3 , —NR 2 —CO—R 4 , —O—CO—R 4 , —CO—O—R 2 , —CO—R 2 , —SO 3 —R 2 , —SO 2 —R 2 , —SO—R 4 , —P(═O)(—O—R 2 )(—O—R 3 ), —NR 2 —R 3 , —O—R 2 , —S—R 2 , —CN, —NO 2 , a halogen, —N-phthalimidyl, —M—N-phthalimidyl, or —M—R 2 , wherein M represents a divalent linking group containing 1 to 8 carbon atoms,

wherein R 2 , R 3 , R 5 and R 6 are independently selected from hydrogen or an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group,

wherein R 4 is selected from an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group,

or wherein at least two groups selected from each R 1 to R 4 together represent the necessary atoms to form a cyclic structure,

or wherein R 5 and R 6 together represent the necessary atoms to form a cyclic structure.

18. A positive-working heat-sensitive lithographic printing plate precursor according to claim 6 wherein O has the structure of formula I:

wherein n is 0, 1, 2 or 3,

wherein each R 1 is selected from hydrogen, an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group, —SO 2 —NH—R 2 , —NH—SO 2 —R 4 , —CO—NR 2 —R 3 , —NR 2 —CO—R 4 , —O—CO—R 4 , —CO—O—R 2 , —CO—R 2 , —SO 3 —R 2 , —SO 2 —R 2 , —SO—R 4 , —P(═O)(—O—R 2 )(—O—R 3 ), —NR 2 —R 3 , —O—R 2 , —S—R 2 , —CN, —NO 2 , a halogen, —N-phthalimidyl, —M—N-phthalimidyl, or —M—R 2 , wherein M represents a divalent linking group containing 1 to 8 carbon atoms,

wherein R 2 , R 3 , R 5 and R 6 are independently selected from hydrogen or an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group,

wherein R 4 is selected from an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group,

or wherein at least two groups selected from each R 1 to R 4 together represent the necessary atoms to form a cyclic structure,

or wherein R 5 and R 6 together represent the necessary atoms to form a cyclic structure.

19. A method of making a heat-sensitive lithographic printing plate precursor according to claim 11 wherein O has the structure of formula I:

wherein n is 0, 1, 2 or 3,

wherein each R 1 is selected from hydrogen, an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group, —SO 2 —NH—R 2 , —NH—SO 2 —R 4 , —CO—NR 2 —R 3 , —NR 2 —CO—R 4 , —O—CO—R 4 , —CO—O—R 2 , —CO—R 2 , —SO 3 —R 2 , —SO 2 —R 2 , —SO—R 4 , —P(═O)(—O—R 2 )(—O—R 3 ), —NR 2 —R 3 , —O—R 2 , —S—R 2 , —CN, —NO 2 , a halogen, —N-phthalimidyl, —M—N-phthalimidyl, or —M—R 2 , wherein M represents a divalent linking group containing 1 to 8 carbon atoms,

wherein R 2 , R 3 , R 5 and R 6 are independently selected from hydrogen or an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group,

wherein R 4 is selected from an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group,

or wherein at least two groups selected from each R 1 to R 4 together represent the necessary atoms to form a cyclic structure,

or wherein R 5 and R 6 together represent the necessary atoms to form a cyclic structure.

20. The positive-working heat-sensitive lithographic printing plate precursor according to claim 1 , wherein the phenyl group of the phenolic monomeric unit of said phenolic resin is chemically modified with an organic substituent comprising a group having the chemical structure of Formula I.

21. The positive-working heat-sensitive lithographic printing plate precursor according to claim 2 , wherein the phenyl group of the phenolic monomeric unit of said phenolic resin is chemically modified with an organic substituent comprising a group having the chemical structure of Formula I.

22. The positive-working heat-sensitive lithographic printing plate precursor according to claim 3 , wherein the phenyl group of the phenolic monomeric unit of said phenolic resin is chemically modified with an organic substituent comprising a group having the chemical structure of Formula I.

23. The method of making a heat-sensitive lithographic printing plate precursor according to claim 11 , wherein the phenyl group of the phenolic monomeric unit of said phenolic resin is chemically modified with an organic substituent comprising a group having the chemical structure of Formula I.

24. The positive-working heat-sensitive lithographic printing plate precursor according to claim 1 , wherein the phenyl group of the phenolic monomeric unit of said phenolic resin is substituted with a group having the structure —N═N—O, wherein the —N═N— group is covalently bound to a carbon atom of the phenyl group, and wherein O is an aromatic group.

25. The positive-working heat-sensitive lithographic printing plate precursor according to claim 2 , wherein the phenyl group of the phenolic monomeric unit of said phenolic resin is substituted with a group having the structure —N═N—O, wherein the —N═N— group is covalently bound to a carbon atom of the phenyl group, and wherein O is an aromatic group.

26. The positive-working heat-sensitive lithographic printing plate precursor according to claim 3 , wherein the phenyl group of the phenolic monomeric unit of said phenolic resin is substituted with a group having the structure —N═N—O, wherein the —N═N— group is covalently bound to a carbon atom of the phenyl group, and wherein O is an aromatic group.

27. The method of making a heat-sensitive lithographic printing plate precursor according to claim 11 , wherein the phenyl group of the phenolic monomeric unit of said phenolic resin is substituted with a group having the structure —N═N—O, wherein the —N═N— group is covalently bound to a carbon atom of the phenyl group, and wherein O is an aromatic group.

28. The positive-working heat-sensitive lithographic printing plate precursor according to claim 13 , wherein the phenyl group of the phenolic monomeric unit of said phenolic resin is substituted with a group having the structure —N═N—O, wherein the —N═N— group is covalently bound to a carbon atom of the phenyl group, and wherein O is an aromatic group.

29. The positive-working heat-sensitive lithographic printing plate precursor according to claim 14 , wherein the phenyl group of the phenolic monomeric unit of said phenolic resin is substituted with a group having the structure —N═N—O, wherein the —N═N— group is covalently bound to a carbon atom of the phenyl group, and wherein O is an aromatic group.

30. The positive-working heat-sensitive lithographic printing plate precursor according to claim 15 , wherein the phenyl group of the phenolic monomeric unit of said phenolic resin is substituted with a group having the structure —N═N—O, wherein the —N═N— group is covalently bound to a carbon atom of the phenyl group, and wherein O is an aromatic group.

31. The method of making a heat-sensitive lithographic printing plate precursor according to claim 16 , wherein the phenyl group of the phenolic monomeric unit of said phenolic resin is substituted with a group having the structure —N═N—O, wherein the —N═N— group is covalently bound to a carbon atom of the phenyl group, and wherein O is an aromatic group.

32. The positive-working heat-sensitive lithographic printing plate precursor according to claim 17 , wherein the phenyl group of the phenolic monomeric unit of said phenolic resin is substituted with a group having the structure —N═N—O, wherein the —N═N— group is covalently bound to a carbon atom of the phenyl group, and wherein O is an aromatic group.

33. The positive-working heat-sensitive lithographic printing plate precursor according to claim 18 , wherein the phenyl group of the phenolic monomeric unit of said phenolic resin is substituted with a group having the structure —N═N—O, wherein the —N═N— group is covalently bound to a carbon atom of the phenyl group, and wherein O is an aromatic group.

34. The positive-working heat-sensitive lithographic printing plate precursor according to claim 19 , wherein the phenyl group of the phenolic monomeric unit of said phenolic resin is substituted with a group having the structure —N═N—O, wherein the —N═N— group is covalently bound to a carbon atom of the phenyl group, and wherein O is an aromatic group.