Alkali-soluble polymer and polymerizable composition thereof

1. A polymerizable composition comprising:

(A) a polymer, which contains a structural unit having a carboxyl group represented by the following formula (1) at a side chain of the structural unit; and

which comprises a functional group represented by the following formula (2) at a side chain of the polymer, the functional group being capable of changing to an acid group through hydrolysis with alkali:

wherein in formula (1), R 1 represents a hydrogen atom or a methyl group; R 2 represents a (n+1)-valent organic linking group containing an ester group represented by —O(C═O)—; 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 indicates an integer of from 1 to 5;

and in formula (2), Q represents a linking group that links X 1 to a main chain of the polymer; X 1 represents a protective group hydrolyzable with an alkali aQueous solution having a pH of 10 or more; and when the functional group represented by the formula (2) gives -Q-OH after hydrolysis, the -Q-OH is an acid group having a pKa of 10 or less;

(B) a compound having an ethylenic unsaturated bond; and

(C) a compound capable of generating a radical by a light or heat.

2. The polymerizable composition according to claim 1 , which further comprises (D) a sensitizing dye.

3. The polymerizable composition according to claim 1 , wherein the compound (C) capable of generating a radical by a light or heat is a compound selected from the group consisting of (a) an aromatic ketone, (b) an onium salt compound, (c) an organic peroxide, (d) a thio compound, (e) a hexaarylbiimidazole compound, (t) a ketoxime ester compound, (g) a borate compound, (h) an azinium compound, (i) a metallocene compound, (j) an active ester compound, and (k) a compound having a carbon-halogen bond.

4. A negative image-recording material, which has an image recording layer comprising the polymerizable composition according to claim 1 .

5. The negative image-recording material according to claim 4 , wherein the image recording layer has a protective layer comprising a water-soluble polymer compound on the image-recording material.

6. A process for image forming, comprising:

performing an imagewise exposure by using an infrared beam having a wavelength of 300 to 1200 nm on the image-recording material according to claim 4 ; and

performing a developing treatment with an aqueous alkali solution.

7. A polymerizable composition comprising:

(A) a polymer, which contains a structural unit having a carboxyl group represented by the following formula (1) at a side chain of the structural unit, and which comprises an acid group represented by the following formula (4) having an acid dissociation constant (pKa) of from 0 to 11 at a side chain of the polymer:

wherein in formula (1), R 1 represents a hydrogen atom or a methyl group; R 2 represents a (n+1)-valent organic linking group containing an ester group represented by —O(C═O)—; 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 indicates an integer of from 1 to 5;

and in formula (4), X 3 represents a single bond that directly links to a main chain of the polymer, or a linking group selected from the group consisting of a carboxylic acid ester group (—COO—), an amido group (—CONH—), a hydrocarbon group and an ether group (—O— or —S—); A 2 -H represents a partial structure that functions as an acid group having an acid dissociation constant (pKa) of from 0 to 11; and m indicates an integer of from 1 to 5,

wherein the acid group is a phenol group, a 2-methoxyphenol group, a 2-chiorophenol group, a methyl 2-hydroxybenzoate group, a 4-methyiphenol group, a 1,3-benzenediol group, a 1-naphthol group, a 1,2-benzenediol group or an ethylacetylacetate group;

(B) a compound having an ethylenic unsaturated bond; and

(C) a compound capable of generating a radical by a light or heat.

8. The polymerizable composition according to claim 7 , which further comprises (D) a sensitizing dye.

9. The polymerizable composition according to claim 7 , wherein the compound (C) capable of generating a radical by a light or a heat is a compound selected from the group consisting of (a) an aromatic ketone, (b) an onium salt compound, (c) an organic peroxide, (d) a thio compound, (e) a hexaarylbiimidazole compound, (f) a ketoxime ester compound, (g) a borate compound, (h) an azinium compound, (i) a metallocene compound, (j) an active ester compound, and (k) a compound having a carbon-halogen bond.

10. A negative image-recording material, which has an image recording layer comprising the polymerizable composition according to claim 7 .

11. The negative image-recording material according to claim 10 , wherein the image recording layer has a protective layer comprising a water-soluble polymer compound on the image-recording material.

12. A process for image forming, comprising:

performing an imagewise exposure by using an infrared beam having a wavelength of 300 to 1200 nm on the image-recording material according to claim 10 ; and

performing a developing treatment with an aqueous alkali solution.

13. The polymerizable composition according to claim 1 , wherein no deposition is formed, when the polymer is dissolved in an alkali aqueous solution having a pH of 10 or more and kept at 25° C. for 60 days.

14. The polymerizable composition according to claim 7 , wherein no deposition is formed, when the polymer is dissolved in an alkali aqueous solution having a pH of 10 or more and kept at 25° C. for 60 days.