Photocurable inkjet printing ink composition

1. A photocurable inkjet printing ink composition containing a photopolymerizable compound and a photopolymerization initiator, wherein in 100 percent by mass of the photocurable inkjet printing ink composition, included are:

a. an acrylamide-based monomer by 22.0 to 50 percent by mass, which is expressed by General Formula (I) below:

CH 2 ═CR4-CON(R5)R6

wherein R4 represents a hydrogen atom or a methyl group; R5 and R6 may be the same or different, and although they are each a hydrogen atom or a substituted or an unsubstituted alkyl group with the carbon number from 1 to 8, they are not a hydrogen atom at the same time; and alternatively, R5 and R6 may be bonded to form a ring together with an adjacent nitrogen atom;

b. a monofunctional monomer other than acrylamide-based monomer by 15 to 70 percent by mass;

c. a polymerizable compound having two or more functionalities by 5.0 to 20.0 percent by mass;

d. an acrylated amine compound having two photopolymerizable functional groups and two amino groups in the molecule by more than 0 percent by mass but no more than 10 percent by mass; and

e. the percentage of monofunctional monomers in the photopolymerizable compound is 60 to 99.5 percent by mass.

2. The photocurable inkjet printing ink composition according to claim 1 , wherein the acrylamide-based monomer is an acryloyl morpholine.

3. The photocurable inkjet printing ink composition according to claim 1 , wherein the photopolymerization initiator contains an acylphosphine oxide photopolymerization initiator and the acylphosphine oxide photopolymerization initiator accounts for 2 to 15 percent by mass relative to 100 percent by mass of the photopolymerizable compound.

4. The photocurable inkjet printing ink composition according to claim 1 , wherein the photopolymerization initiator contains a thioxanthone photopolymerization initiator and the thioxanthone photopolymerization initiator accounts for 5 percent by mass or less relative to 100 percent by mass of the photopolymerizable compound.

5. The photocurable inkjet printing ink composition according to claim 1 , which contains a coloring agent.

6. The photocurable inkjet printing ink composition according to claim 1 , of which viscosity at 25° C. is 5.0 to 30 m·Pas.

7. The photocurable inkjet printing ink composition according to claim 2 , wherein the photopolymerization initiator contains an acylphosphine oxide photopolymerization initiator and the acylphosphine oxide photopolymerization initiator accounts for 2 to 15 percent by mass relative to 100 percent by mass of the photopolymerizable compound.

8. The photocurable inkjet printing ink composition according to claim 2 , wherein the photopolymerization initiator contains a thioxanthone photopolymerization initiator and the thioxanthone photopolymerization initiator accounts for 5 percent by mass or less relative to 100 percent by mass of the photopolymerizable compound.

9. The photocurable inkjet printing ink composition according to claim 2 , which contains a coloring agent.

10. The photocurable inkjet printing ink composition according to claim 2 , of which viscosity at 25° C. is 5.0 to 30 mPa·s.

11. The photocurable inkjet printing ink composition according to claim 3 , wherein the photopolymerization initiator contains a thioxanthone photopolymerization initiator and the thioxanthone photopolymerization initiator accounts for 5 percent by mass or less relative to 100 percent by mass of the photopolymerizable compound.

12. The photocurable inkjet printing ink composition according to claim 3 , which contains a coloring agent.

13. The photocurable inkjet printing ink composition according to claim 3 , of which viscosity at 25° C. is 5.0 to 30 mPa·s.

14. The photocurable inkjet printing ink composition according to claim 4 , which contains a coloring agent.