Photosensitive composition and photosensitive lithographic printing plate

1. A photosensitive composition comprising an ethylenically unsaturated monomer, a photopolymerization initiator composition and a polymer binder, wherein the photopolymerization initiator composition contains a compound represented by the following formula (1-b), (2-1) or (2-3) and further contains a titanocene compound, a monoalkyltriaryl borate compound or an iron arene complex compound:

CBr 3 —(C═O)—X—R 3   formula (1-b)

wherein R 3 is a substituent; X is —O— or —NR 4 —, in which R 4 is a hydrogen atom or an alkyl group, provided that R 3 and R 4 may combine with each other to form a ring;

wherein Z 1 and Z 2 are each a halogen atom; X is a hydrogen atom or an electron-withdrawing group; Y 1 is —SO 2 —; Q 1 is an arylene group or a divalent heterocyclic group; L is a linkage group; W is a carboxyl group or its salt, sulfo group or its salt, a phosphoric acid group or its salt, hydroxyl group, quaternary ammonium group or a polyethyleneoxy group; n is 0 or 1;

wherein Q 3 is an alkyl group, an aryl group or a heterocyclic group; X 1 , X 2 and X 3 are each a halogen atom; m is an integer of 0 to 4 and n is an integer of 1 to 5.

2. The photosensitive composition of claim 1 , wherein the photopolymerization initiator composition contains the compound represented by formula (1-b).

3. The photosensitive composition of claim 1 , wherein the photopolymerization initiator composition contains the compound represented by formula (2-1).

4. The photosensitive composition of claim 1 , wherein the photopolymerization initiator composition contains the compound represented by formula (2-3).

5. The photosensitive composition of claim 1 , wherein the photopolymerization composition contains the titanocene compound.

6. The photosensitive composition of claim 5 , wherein the photosensitive composition contains a dye exhibiting an absorption maximum at a wavelength of 350 to 450 nm.

7. The photosensitive composition of claim 1 , wherein the photopolymerization composition contains the monoalkyltriaryl borate compound.

8. The photosensitive composition of claim 7 , wherein the photosensitive composition contains a dye exhibiting an absorption maximum at a wavelength of 350 to 450 nm.

9. The photosensitive composition of claim 1 , wherein the photopolymerization composition contains the iron arene complex compound.

10. The photosensitive composition of claim 9 , wherein the photosensitive composition contains a dye exhibiting an absorption maximum at a wavelength of 350 to 450 nm.

11. The photosensitive composition of claim 1 , wherein the photosensitive composition contains a dye exhibiting an absorption maximum at a wavelength of 350 to 600 nm.

12. The photosensitive composition of claim 1 , wherein the photosensitive composition contains a dye exhibiting an absorption maximum at a wavelength of 350 to 450 nm.

13. The photosensitive composition of claim 1 , wherein the ethylenically unsaturated monomer is a reaction product of a polyhydric alcohol containing a tertiary amino group, a diisocyanate compound and an ethylenically unsaturated compound containing a hydroxy group.

14. The photosensitive composition of claim 1 , wherein the ethylenically unsaturated monomer is a compound represented by the following formula (4) or (5):

wherein Q 1 is

 or —S—; R 4 is an alkyl group, a hydroxyalkyl group or an aryl group; R 1 and R 2 are each a hydrogen atom, an alkyl group or an alkoxy group; R 3 is a hydrogen atom, methyl or ethyl; X 1 is a divalent linkage group having 2 to 12 carbon atoms; X 2 is a divalent, trivalent or tetravalent group, or

 in which Z is a hydrogen atom, an alkyl group, an alkenyl group, aryl group, a halogen atom, an alkoxy group or a heterocyclic group; p is an integer of 1 to 4; q is an integer of 1 to 3; D 1 and D 2 are each a divalent linkage group having 1 to 5 carbon atoms; E is a divalent linkage group having 2 to 12 carbon atoms, an aliphatic group containing a 5- to 7-membered heterocyclic group containing one or two atoms selected from the group consisting of a nitrogen atom, oxygen atom and sulfur atom, an arylene group having 6 to 12 carbon atoms or a 5- or 6-membered aromatic heterocyclic group; a is an integer of 0 to 4; b is 0 or 1; c is an integer of 1 to 3; m is an integer of 2 to 4, depending on the valence number of Q 1 ; n is an integer of 1 to m, provided that groups having the same definition may be the same of different;

wherein Q 2 is

 R 8 is an alkyl group, a hydroxyalkyl group or an aryl group; R 5 and R 6 are each a hydrogen atom, an alkyl group or an alkoxyalkyl group; R 7 is a hydrogen atom, methyl or ethyl group; D 3 and D 4 are each a saturated hydrocarbon group having 1 to 5 carbon atoms; F is a saturated hydrocarbon group having 2 to 12 carbon atoms, a 5 to 7-membered alicyclic group containing one or two of nitrogen atom, oxygen atom and sulfur atom, as a ring-forming member, an arylene group having 6 to 12 carbon atoms, or a 5- or 6-membered aromatic heterocyclic group; d and e are each an integer of 1 to 4; g is an integer of 2 to 4, depending on the valence number of Q 2 ; f is an integer of 1 to g, provided that groups having the same definition may be the same or different.

15. A photosensitive lithographic printing plate comprising a support having at least a hydrophilic surface and a photosensitive layer comprising an ethylenically unsaturated monomer, a photopolymerization initiator composition and a polymer binder, wherein the photopolymerization initiator composition contains a compound represented by the following formula (1-b), (2-1) or (2-3) and further contains a titanocene compound, a monoalkyltriaryl borate compound or an iron arene complex compound:

CBr 3 —(C═O)—X—R 3   formula (1-b)

wherein R 3 is a substituent; X is —O— or —NR 4 —, in which R 4 is a hydrogen atom or an alkyl group, provided that R 3 and R 4 may combine with each other to form a ring;

wherein Z 1 and Z 2 are each a halogen atom; X is a hydrogen atom or an electron-withdrawing group; Y 1 is —SO 2 —; Q 1 is an arylene group or a divalent heterocyclic group; L is a linkage group; W is a carboxyl group or its salt, sulfo group or its salt, a phosphoric acid group or its salt, hydroxyl group, quaternary ammonium group or a polyethyleneoxy group; n is 0 or 1;

wherein Q 3 is an alkyl group, an aryl group or a heterocyclic group; X 1 , X 2 and X 3 are each a halogen atom; m is an integer of 0 to 4 and n is an integer of 1 to 5.

16. The photosensitive lithographic printing plate of claim 15 , wherein the photopolymerization initiator composition contains the compound represented by formula (1-b).

17. The photosensitive lithographic printing plate of claim 15 , wherein the photopolymerization initiator composition contains the compound represented by formula (2-1).

18. The photosensitive lithographic printing plate of claim 15 , wherein the photopolymerization initiator composition contains the compound represented by formula (2-3).

19. The photosensitive lithographic printing plate of claim 15 , wherein the photopolymerization composition contains the titanocene compound.

20. The photosensitive lithographic printing plate of claim 15 , wherein the photopolymerization composition contains the monoalkyltriaryl borate compound.

21. The photosensitive lithographic printing plate of claim 15 , wherein the photopolymerization composition contains the iron arene complex compound.