Fine particle dispersion, ink composition using the same, and ink-jet recording method

1. A fine particle dispersion, wherein fine particles comprising an oil-soluble dye having an oxidation potential higher than 1.0 V vs SCE and a polymer having at least one of an amide group, a glycidyl group and a hydroxyl group are dispersed in an aqueous medium, and the oil-soluble dye is represented by Formula (Y-II), Formula (Y-III) or Formula (Y-IV):

wherein, in Formula (Y-II), R 1 and R 3 each independently represent a hydrogen atom, a cyano group, an alkyl group, a cycloalkyl group, an aralkyl group, an alkoxy group, an alkylthio group, an arylthio group, an aryl group or an ionic hydrophilic group, R 2 represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aralkyl group, a carbamoyl group, an acyl group, an aryl group or a heterocyclic group, and R 4 represents a heterocyclic group;

in Formula (Y-III), R 5 represents a hydrogen atom, a cyano group, an alkyl group, a cycloalkyl group, an aralkyl group, an alkoxy group, an alkylthio group, an arylthio group, an aryl group or an ionic hydrophilic group, Za represents —N═, —NH—, or C(R 11 ), Zb and Zc each independently represent —N═ or C(R 11 )═, where R 11 represents a hydrogen atom or a nonmetallic substituent group, and R 6 represents a heterocyclic group;

in Formula (Y-IV), R 7 and R 9 each independently represent a hydrogen atom, a cyano group, an alkyl group, a cycloalkyl group, an aralkyl group, an aryl group, an alkylthio group, an arylthio group, an alkoxycarbonyl group, a carbamoyl group or an ionic hydrophilic group, R 8 represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, a cyano group, an acylamino group, a sulfonylamino group, an alkoxycarbonylamino group, an ureido group, an alkylthio group, an arylthio group, an alkoxycarbonyl group, a carbamoyl group, a sulfamoyl group, a sulfonyl group, an acyl group, an alkylamino group, an arylamino group, a hydroxy group or an ionic hydrophilic group, and R 10 represents a heterocyclic group.

2. The fine particle dispersion according to claim 1 , wherein the weight average molecular weight of the polymer is 2000 to 50000.

3. An ink composition comprising a fine particle dispersion, wherein fine particles comprising an oil-soluble dye having an oxidation potential higher than 1.0 V vs SCE and a polymer having at least one of an amide group, a glycidyl group and a hydroxyl group are dispersed in an aqueous medium, and the oil-soluble dye is represented by Formula (Y-II), Formula (Y-III) or Formula (Y-IV):

wherein, in Formula (Y-II), R 1 and R 3 each independently represent a hydrogen atom, a cyano group, an alkyl group, a cycloalkyl group, an aralkyl group, an alkoxy group, an alkylthio group, an arylthio group, an aryl group or an ionic hydrophilic group, R 2 represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aralkyl group, a carbamoyl group, an acyl group, an aryl group or a heterocyclic group, and R 4 represents a heterocyclic group;

in Formula (Y-III), R 5 represents a hydrogen atom, a cyano group, an alkyl group, a cycloalkyl group, an aralkyl group, an alkoxy group, an alkyithjo group, an arylthio group, an aryl group or an ionic hydrophilic group, Za represents —N═, —NH—, or C(R 11 ), Zb and Zc each independently represent —N═, or C(R 11 )═, where R 11 represents a hydrogen atom or a nonmetallic substituent group, and R 6 represents a heterocyclic group;

in Formula (Y-IV), R 7 and R 9 each independently represent a hydrogen atom, a cyano group, an alkyl group, a cycloalkyl group, an aralkyl group, an aryl group, an alkylthio group, an arylthio group, an alkoxycarbonyl group, a carbamoyl group or an ionic hydrophilic group, R 8 represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, a cyano group, an acylamino group, a sulfonylamino group, an alkoxycarbonylamino group, an ureido group, an alkylthio group, an arylthio group, an alkoxycarbonyl group, a carbamoyl group, a sulfamoyl group, a sulfonyl group, an acyl group, an alkylamino group, an arylamino group, a hydroxy group or an ionic hydrophilic group, and R 10 represents a heterocyclic group.

4. The ink composition according to claim 3 , wherein the weight average molecular weight of the polymer is 2000 to 50000.

5. The ink composition according to claim 3 , further comprising at least one compound selected from the group consisting of alcohols, polyvalent alcohols and water-soluble glycol ethers.

6. An ink-jet recording method comprising recording an image on a recording material using the ink composition according to claim 3 .

7. An ink-jet recording method comprising recording an image on a recording material using the ink composition according to claim 4 .

8. An ink-jet recording method comprising recording an image on a recording material using the ink composition according to claim 5 .

9. The ink-jet recording method according to claim 6 , wherein the recording material is a recording material comprising an inorganic fine particle-containing porous ink receiving layer.

10. The ink-jet recording method according to claim 7 , wherein the recording material is a recording material comprising an inorganic fine particle-containing porous ink receiving layer.

11. The ink-jet recording method according to claim 8 , wherein the recording material is a recording material comprising an inorganic fine particle-containing porous ink receiving layer.

12. The ink composition according to claim 3 , wherein the polymer comprises a hydrophobic polymer moiety and a hydrophilic polymer moiety.

13. The ink composition according to claim 3 , wherein the polymer is a vinyl polymer.

14. The ink composition according to claim 12 , wherein, in the polymer, the content amount of the hydrophobic polymer moiety is 60 to 80% by mass, and the content amount of the hydrophilic polymer moiety is 20 to 40% by mass.

15. The ink composition according to claim 3 , wherein, in the polymer, the content amount of the amide group is 10 to 90% by mass, the content amount of the glycidyl group is 10 to 90% by mass, and the content amount of the hydroxyl group is 10 to 70% by mass.

16. The ink composition according to claim 3 , wherein the solubility of the oil-soluble dye in water at 25° C. is 0.1 g or less, the solubility being the mass of a dye soluble in 100 g of water.

17. The ink composition according to claim 3 , wherein the content amount of the oil-soluble dye in the fine particle dispersion is 0.2 to 6% by mass.

18. The ink composition according to claim 3 , wherein the amount of the polymer used in the fine particle dispersion is 50 to 600 parts by mass per 100 parts by mass of the oil-soluble dye.

19. The ink composition according to claim 3 , wherein the content amount of the fine particles in the fine particle dispersion is 2 to 30% by mass.

20. The ink composition according to claim 3 , wherein the average particle size of the fine particles is 3 to 200 nm.

21. The fine particle dispersion according to claim 1 , wherein the polymer has a glycidyl group.

22. The ink composition according to claim 3 , wherein the polymer has a glycidyl group.

23. The ink jet recording method according to claim 6 , wherein the polymer has a glycidyl group.