Actinic ray curable inkjet ink composition, printed article, shaped printed product, and printed article forming method

1. An actinic ray curable ink composition for inkjet recording comprising:

a colorant;

a polymerization initiator;

a polymerizable monomer comprising a monofunctional monomer in an amount of 90% by mass or more with respect to a total mass of the polymerizable monomer; and

organic fine particles that are crosslinked,

wherein the organic fine particles are free from a radical polymerizable group, and

the organic fine particles have a network structure in which polymers are bonded to each other in a three-dimensional form.

2. The ink composition according to claim 1 , wherein a solubility parameter of the organic fine particles is in a range of from 30 to 50 (MPa) 1/2 .

3. The ink composition according to claim 1 , wherein the organic fine particles comprise at least one resin selected from the group consisting of an acrylic resin, an acrylic-styrene resin, an epoxy resin, a urethane resin and a polyamide resin.

4. The ink composition according to claim 1 , wherein the organic fine particles have a volume average particle diameter in a range of from 0.01 μm to 3 μm.

5. The ink composition according to claim 1 , wherein a content of the polymerizable monomer is 50% by mass or more with respect to a total mass of the ink composition.

6. The ink composition according to claim 1 , wherein the polymerizable monomer comprises a monofunctional monomer and a polyfunctional monomer, and a mass ratio of the monofunctional monomer to the polyfunctional monomer (monofunctional monomer:polyfunctional monomer) is in a range of from 90:10 to 99.9:0.1.

7. The ink composition according to claim 1 , wherein the monofunctional monomer is a radical polymerizable monomer.

8. The ink composition according to claim 7 , wherein the radical polymerizable monomer comprises an acrylate compound and a N-vinyl compound.

9. The ink composition according to claim 7 , wherein the radical polymerizable monomer comprises an acrylate having a cyclic structure in a molecule thereof.

10. The ink composition according to claim 1 , further comprising a chain transfer agent.

11. The ink composition according to claim 10 , wherein the chain transfer agent is a polyfunctional thiol compound having a secondary thiol group or a tertiary thiol group.

12. The ink composition according to claim 1 , wherein a mass ratio of a mass of the ink composition before curing to a mass of an image obtained by curing the ink composition by actinic rays and drying (mass of the ink composition before curing:mass of the image obtained after curing) is in a range of from 100:95 to 100:100.

13. The ink composition according to claim 1 , wherein a content of water is 3% by mass or less with respect to a total mass of the ink composition.

14. The ink composition according to claim 1 , wherein the ink composition substantially contains no solvent other than the polymerizable monomer.

15. A method for forming a printed article comprising:

forming an image by ejecting, onto a recording medium, the actinic ray curable ink composition for inkjet recording according to claim 1 , and

forming a printed article having a cured image on the recording medium by irradiation of the actinic ray onto the image so that the ink composition in the image is cured.

16. The ink composition according to claim 1 , wherein a content of the organic fine particles is in a range of from 8 to 20% by mass with respect to a total mass of the ink composition.