Pigment dispersion, method for producing pigment dispersion, water-based ink composition comprising pigment dispersion, ink jet recording method using ink composition and ink jet recorded matter using ink composition

• US 20090233059A1
• Filed: 03/06/2009
• Published: 09/17/2009
• Est. Priority Date: 03/06/2008
• Status: Abandoned Application

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Nagasaki, Hiroshi, Tamura, Yoshimasa, Ota, Hitoshi
• Application Number:
  US12/381,025
• Publication Number:
  US 20090233059A1
• Time in Patent Office: Days
• US Class Current: 428/195.100
• CPC Class Codes: C09D 11/322 Pigment inks
• CPC Class Codes: C09D 11/38 characterised by non-macromolecular additives other than solvents, pigments or dyes
• CPC Class Codes: Y10T 428/24802 Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.]

Abstract

A water-based ink composition that has high ejection stability even when it is used in an ink jet recording method that involves a high driving frequency and that can achieve high-resolution printing, a pigment dispersion for use in the water-based ink composition, and a method for producing the pigment dispersion are provided. Moreover, an inkjet recording method and a recorded matter using the water-based ink composition are provided.

A pigment dispersion of the present invention is a pigment dispersion at least containing a pigment, a water-insoluble polymer that coats the pigment to make the pigment dispersible in water, a wetting agent, and water, wherein the pigment dispersion is prepared by heating a dispersion at least containing the pigment, the water-insoluble polymer, and 0.1 mass % to 10 mass % of the wetting agent relative to the total amount of the dispersion.

Claims

1. A pigment dispersion at least comprising a pigment, a water-insoluble polymer that coats the pigment to make the pigment dispersible in water, a wetting agent, and water,

wherein the pigment dispersion is prepared by heating a dispersion at least containing the pigment, the water-insoluble polymer, and 0.1 mass % to 10 mass % of the wetting agent relative to the total amount of the dispersion.

2. The pigment dispersion according to claim 1, at least comprising the pigment, the water-insoluble polymer that coats the pigment to make the pigment dispersible in water, the wetting agent, and water,

wherein the pigment dispersion is prepared by heating a dispersion at least containing a dispersoid constituted by the pigment coated with the water-insoluble polymer, 0.1 mass % to 10 mass % of the wetting agent relative to the total amount of the dispersion, and water.

3. The pigment dispersion according to claim 1, wherein the wetting agent contained in the dispersion is at least one selected from the group consisting of an acetylene glycol-based surfactant, an acetylene alcohol-based surfactant, a siloxane-based surfactant, a fluorine-based surfactant, a polyoxyalkylene-based nonionic surfactant, an anionic surfactant, a resin solvent, an amide compound, an imidazole derivative, an azine compound, an azole compound, an amidine derivative, a hydroxypyridine derivative, a purine derivative, a hydroxy cyclic amine compound, and a glycerol ether compound represented by formula (I):

wherein R represents a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms and optionally containing a double bond, a triple bond, or a substituent, or a substituted or unsubstituted aryl group; and

X represents a hydrogen atom, a hydroxyl group, or a linear or branched alkoxy group having 1 to 5 carbon atoms.

4. The pigment dispersion according to claim 1, wherein the heating temperature during the heat treatment is in the range of 65°

C. to 100°

C. and the heating time is in the range of 30 minutes to 100 hours.

5. The pigment dispersion according to claim 1, wherein the dispersion further contains a water-soluble organic solvent.

6. The pigment dispersion according to claim 5, wherein the water-soluble organic solvent is at least one selected from the group consisting of a monohydric alcohol, a polyhydric alcohol, a sugar, a glycol ether, and a 1,2-alkyldiol.

13. A water-based ink composition comprising the pigment dispersion according to claim 1 or a pigment dispersion obtained by the method for producing a pigment dispersion according to claim 7.

14. The water-based ink composition according to claim 13, comprising at least one penetrant selected from the group consisting of a monohydric alcohol, a glycol ether, and a 1,2-alkyldiol.

15. The water-based ink composition according to claim 13, comprising at least one humectant selected from the group consisting of a polyhydric alcohol, a sugar, a lactam, and a urea.

16. The water-based ink composition according to claim 13, further comprising a polymer emulsion.

17. An ink jet recording method comprising:

ejecting droplets of an ink composition and causing the droplets to adhere on a recording medium to conduct printing, wherein the water-based ink composition according to claim 13 is used.

18. A recorded matter recorded by the ink jet recording method according to claim 17.

7. A method for producing a pigment dispersion for use in a water-based ink composition, the method comprising:

a heat treatment step of heating a dispersion at least containing a pigment, a water-insoluble polymer that coats the pigment to make the pigment dispersible in water, and a wetting agent,

wherein, in the heat treatment step, the total amount of the wetting agent is in the range of 0.1 mass % to 10 mass % relative to the total amount of the dispersion.

8. The method for producing a pigment dispersion according to claim 7, wherein the heat treatment step comprises heating a dispersion at least containing a dispersoid constituted by the pigment coated with the water-insoluble polymer, the wetting agent, and water, and

in the heat treatment step, the total amount of the wetting agent is in the range of 0.1 mass % to 10 mass % relative to the total amount of the dispersion.

9. The method for producing a pigment dispersion according to claim 7, wherein the wetting agent is at least one selected from the group consisting of an acetylene glycol-based surfactant, an acetylene alcohol-based surfactant, a siloxane-based surfactant, a fluorine-based surfactant, a polyoxyalkylene-based nonionic surfactant, an anionic surfactant, a resin solvent, an amide compound, an imidazole derivative, an azine compound, an azole compound, an amidine derivative, a hydroxypyridine derivative, a purine derivative, a hydroxy cyclic amine compound, and a glycerol ether compound represented by formula (I):

wherein R represents a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms and optionally containing a double bond, a triple bond, or a substituent, or a substituted or unsubstituted aryl group;

and X represents a hydrogen atom, a hydroxyl group, or a linear or branched alkoxy group having 1 to 5 carbon atoms.

10. The method for producing the pigment dispersion according to claim 7, wherein, in the heat treatment step, the heating temperature is in the range of 65°

C. to 100°

C. and the heating time is in the range of 30 minutes to 100 hours.

11. The method for producing the pigment dispersion according to claim 7, wherein the dispersion further contains a water-soluble organic solvent.

12. The method for producing the pigment dispersion according to claim 11, wherein the water-soluble organic solvent is at least one selected from the group consisting of a monohydric alcohol, a polyhydric alcohol, a sugar, a glycol ether, and a 1,2-alkyldiol.