Polymerizable composition and image-recording material using the same

1. A negative-working polymerizable composition comprising:

a dye which is soluble in an organic solvent and in an alkaline aqueous solution and has an absorption at a range of 700 to 1200 nm, the dye having a methyl ester group, which is a carboxylate ester;

a radical polymerization initiator;

a compound having an ethylenically unsaturated bond; and

a binder polymer which is substantially soluble in the alkaline aqueous solution and insoluble in water,

wherein the radical polymerization initiator is an onium salt represented by the following formulae (RI-III):

wherein R 31 , R 32 and R 33 each independently represents an aryl group substituted by a halogen atom; and Z 31 represents a monovalent anion and is a halide ion, a perchlorate ion, a hexafluorophosphate ion, a tetrafluoroborate ion, a sulfonate ion, a sulfinate ion, a thiosulfonate ion or a sulfate ion.

2. The polymerizable composition according to claim 1 , wherein the dye has at least one functional group selected from the group consisting of an alkali water-dissociative group and a functional group capable of being decomposed with an alkali water.

3. The polymerizable composition according to claim 1 , which comprises the dye in an amount of from 0.01 to 40% by weight based on the total solid components constituting the polymerizable composition.

4. The polymerizable composition according to claim 1 , which comprises the radical polymerization initiator in amount of from 0.1 to 50% by weight based on the total solid components constituting the polymerizable composition.

5. The polymerizable composition according to claim 1 , which comprises the compound having an ethylenically unsaturated bond in an amount of from 20 to 70% by weight based on the total solid components constituting the polymerizable composition.

6. The polymerizable composition according to claim 1 , wherein the binder polymer contains a structural unit having an alkali-soluble group, the structural unit being represented by the following formula (I):

wherein R 1 represents a hydrogen atom or a methyl group, R 2 represents a linking group constituted by two or more kinds of atoms selected from the group consisting of a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom, a sulfur atom and a halogen atom, with the number of the atoms being from 2 to 82, A represents an oxygen atom or —NR 3 —, R 3 represents a hydrogen atom or a monovalent hydrocarbon group having from 1 to 10 carbon atoms, and n represents an integer of from 1 to 5.

7. The polymerizable composition according to claim 1 , wherein the dye is a cyanine dye.

8. An image-forming material comprising a support and a recording layer containing the polymerizable composition according to claim 1 .

9. A lithographic printing plate making method comprising:

image-wise exposing a layer comprising the polymerizable composition according to claim 1 on a support with light having a wavelength of 700 to 1200 nm, and removing the unexposed areas of the layer using an alkaline aqueous solution.

10. The polymerizable composition according to claim 1 , wherein the dye has a diarylamino group as a substituent.

11. A lithographic printing plate making method comprising:

image-wise exposing a layer comprising a negative-working polymerizable composition on a support with light having a wavelength of 700 to 1200 nm and removing the unexposed areas of the layer using an alkaline aqueous solution,

wherein the polymerizable composition comprises:

a dye having a methyl ester group, which is a carboxylate ester, wherein the dye is soluble in an organic solvent and in an alkaline aqueous solution and has an absorption at a range of 700 to 1200 nm;

a radical polymerization initiator;

a compound having an ethylenically unsaturated bond; and

a binder polymer,

wherein the radical polymerization initiator is an onium salt represented by the following formulae (RI-III):

wherein R 31 , R 32 and R 33 each independently represents an aryl group substituted by a halogen atom; and Z 31 represents a monovalent anion and is a halide ion, a perchlorate ion, a hexafluorophosphate ion, a tetrafluoroborate ion, a sulfonate ion, a sulfinate ion, a thiosulfonate ion or a sulfate ion.

12. A polymerizable composition comprising:

a cyanine dye having a diarylamino group as a substituent and which is soluble in an organic solvent and in an alkaline aqueous solution, and which has an absorption at a range of 700 to 1200 nm;

a radical polymerization initiator;

a compound having an ethylenically unsaturated bond; and

a binder polymer which is substantially soluble in the alkaline aqueous solution and insoluble in water,

wherein the cyanine dye has at least one functional group selected from the group consisting of an alkali water-dissociative group and a functional group capable of being decomposed with an alkali water;

the binder polymer contains a structural unit having an alkali-soluble group, the structural unit being represented by the following formula (I):

wherein R 1 represents a hydrogen atom or a methyl group, R 2 represents a linking group constituted by two or more kinds of atoms selected from the group consisting of a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom, a sulfur atom and a halogen atom, with the number of the atoms being from 2 to 82, A represents an oxygen atom or —NR 3 —, R 3 represents a hydrogen atom or a monovalent hydrocarbon group having from 1 to 10 carbon atoms, and n represents an integer of from 1 to 5:

and wherein the radical polymerization initiator is an onium salt represented by the following formulae (RI-III):

wherein R 31 , R 32 and R 33 each independently represents an aryl group substituted by a halogen atom; and Z 31 represents a monovalent anion and is a halide ion, a perchlorate ion, a hexafluorophosphate ion, a tetrafluoroborate ion, a sulfonate ion, a sulfinate ion, a thiosulfonate ion or a sulfate ion.

13. The polymerizable composition according to claim 12 , which comprises the dye in an amount of from 0.01 to 40% by weight based on the total solid components constituting the polymerizable composition.

14. The polymerizable composition according to claim 12 , which comprises the radical polymerization initiator in amount of from 0.1 to 50% by weight based on the total solid components constituting the polymerizable composition.

15. The polymerizable composition according to claim 12 , which comprises the compound having an ethylenically unsaturated bond in an amount of from 20 to 70% by weight based on the total solid components constituting the polymerizable composition.

16. An image-forming material comprising a support and a recording layer containing the polymerizable composition according to claim 12 .

17. A lithographic printing plate making method comprising:

image-wise exposing a layer comprising the polymerizable composition according to claim 12 on a support with light having a wavelength of 700 to 1200 nm, and removing the unexposed areas of the layer using an alkaline aqueous solution.

18. The polymerizable composition according to claim 12 , wherein the anion of the radical polymerization initiator onium salt is a perchlorate ion, a hexafluorophosphate ion, a tetrafluoroborate ion, a sulfonate ion or a sulfinate ion.