Ink composition, ink jet recording method, method for producing planographic printing plate and planographic printing plate

1. An ink composition comprising:

(A) a polymerization initiator;

(B) a (meth)acrylic acid ester or amide having an alicyclic group as a substituent and, represented by the following formula (I) or (II):

wherein R 1 represents a hydrogen atom or a methyl group; R 2 to R 12 each independently represents a hydrogen atom or an alkyl group, with the proviso that at least two of R 2 to R 12 respectively represent an alkyl group; Z represents an oxygen atom or —NR 13 —; R 13 represents a hydrogen atom or an alkyl group; and X represents a single bond or a divalent organic group; and

(C) another polymerizable compound,

wherein the ink composition has a viscosity of from 7 to 30 mPa•s within an ejecting temperature range of from 25 to 50 ° C.

2. The ink composition of claim 1 further comprising a colorant.

3. The ink composition of claim 2 further comprising a sensitizing dye.

4. An ink jet recording ink of the composition according to claim 3 .

5. An ink jet recording method comprising:

ejecting the ink composition of claim 3 onto an recording medium; and

curing the ejected ink composition by irradiating actinic radiation to the ink composition.

6. A method of producing a planographic printing plate, the method comprising:

ejecting the ink composition of claim 3 onto a hydrophilic support; and

curing the ejected ink composition by irradiating activation radiation to the ink composition and thereby forming a hydrophobic image of the cured ink composition on the hydrophilic support.

7. A planographic printing plate produced by the method of producing a planographic printing plate according to claim 6 .

8. An ink jet recording ink of the composition according to claim 2 .

9. An ink jet recording method comprising:

ejecting the ink composition of claim 2 onto a recording medium; and

curing the ejected ink composition by irradiating actinic radiation to the ink composition.

10. A method of producing a planographic printing plate, the method comprising:

ejecting the ink composition of claim 2 onto a hydrophilic support; and

curing the ejected ink composition by irradiating actinic radiation to the ink composition and thereby forming a hydrophobic image of the cured ink composition on the hydrophilic support.

11. A planographic printing plate produced by the method of producing a planographic printing plate according to claim 10 .

12. The ink composition of claim 1 further comprising a sensitizing dye.

13. An ink jet recording ink of the composition according to claim 12 .

14. An ink jet recording method comprising:

ejecting the ink composition of claim 12 onto an recording medium; and

curing the ejected ink composition by irradiating actinic radiation to the ink composition.

15. A method of producing a planographic printing plate, the method comprising:

ejecting the ink composition of claim 12 onto a hydrophilic support; and

curing the ejected ink composition by irradiating actinic radiation to the ink composition and thereby forming a hydrophobic image of the cured ink composition on the hydrophilic support.

16. A planographic printing plate produced by the method of producing a planographic printing plate according to claim 15 .

17. A method of producing a planographic printing plate, the method comprising:

ejecting the ink composition of claim 1 onto a hydrophilic support; and

curing the ejected ink composition by irradiating with actinic radiation to the ink composition and thereby forming a hydrophobic image of the cured ink composition on the hydrophilic support.

18. An ink jet recording ink of the composition according to claim 1 .

19. An ink jet recording method comprising:

ejecting the ink composition of claim 1 onto a recording medium; and

curing the ejected ink composition by irradiating actinic radiation to the ink composition.

20. A planographic printing plate produced by the method of producing a planographic printing plate according to claim 17 .

21. The ink composition of claim 1 , wherein the alkyl group represented by any one of R 2 to R 12 is selected from the group consisting of a methyl group, an ethyl group, an isopropyl group, and a tert-butyl group.

22. The ink composition of claim 1 , wherein the alkyl group represented by any one of R 2 to R 12 is a methyl group.

23. The ink composition of claim 1 , wherein the total content of the (meth)acrylic acid ester or amide (B) represented by Formula (I) or (II) and the another polymerizable compound (C) is in a range from 45% by mass to 95% by mass with respect to the total mass of the ink composition.

24. The ink composition of claim 1 , wherein the content of the (meth)acrylic acid ester or amide (B) represented by Formula (I) or (II) is in a range from 3 to 35% by mass with respect to the total mass of the ink composition.

25. The ink composition of claim 1 , wherein the surface tension of the ink composition is from 20 to 30 mN/m.

26. The ink composition of claim 1 , wherein the polymerization initiator (A) comprises an acylphosphine oxide compound.

27. The ink composition of claim 1 , further comprising a pigment as a colorant.

28. The ink composition of claim 1 , wherein the (meth)acrylic acid ester or amide (B) represented by Formula (I) or (II) is selected from the group consisting of compounds B-3, B-6, B-11 and B-13: