Radiation-curable inks
Radiation-curable ink compositions and methods of printing including the compositions are disclosed. In some embodiments, a radiation-curable hot melt ink composition includes a colorant, a polymerizable monomer, and a photoinitiating system. The photoinitiating system can include 0.5-1.5% by weight of an aromatic ketone photoinitiator, 2-10% by weight of an amine synergist, 3-8% by weight of an alpha-cleavage type photoinitiator, and 0.5-1.5% by weight of a photosensitizer.
1. A radiation-curable hot melt ink composition comprising:
a colorant;
a polymerizable monomer; and
a photoinitiating system comprising 0.5-1.5% by weight of an aromatic ketone photoinitiator, 2-10% by weight of an amine synergist, 3-8% by weight of a second photoinitiator different than the aromatic ketone photoinitiator and capable of undergoing alpha cleavage, and 0.5-1.5% by weight of a photosensitizer.
2. The radiation-curable hot melt ink composition of claim 1 , wherein the polymerizable monomer is a multi-functional monomer.
3. The radiation-curable hot melt ink composition of claim 2 , wherein the polymerizable monomer is an acrylate monomer.
4. The radiation-curable hot melt ink composition of claim 1 , further comprising a diluent.
5. The radiation-curable hot melt ink composition of claim 4 , wherein the diluent is a mono-functional or di-functional monomer.
6. The radiation-curable hot melt ink composition of claim 5 , wherein the polymerizable monomer is a multi-functional monomer.
7. The radiation-curable hot melt ink composition of claim 6 , wherein the polymerizable monomer is an acrylate monomer.
8. The radiation-curable hot melt ink composition of claim 1 , wherein the radiation-curable hot melt ink composition has a viscosity ranging from about 1 centipoise to about 50 centipoise.
9. The radiation-curable hot melt ink composition of claim 1 , further comprising a vehicle.
10. A radiation-curable liquid ink composition comprising:
a colorant;
a liquid polymerizable monomer; and
a photoinitiating system comprising 2-4% by weight of an aromatic ketone photoinitiator, 5-10% by weight of an amine synergist, 5-10% by weight of a second photoinitiator different than the aromatic ketone photoinitiator and capable of undergoing alpha cleavage, and 2-4% by weight of a photosensitizer.
11. The radiation-curable liquid ink composition of claim 10 , wherein the polymerizable monomer is a multi-functional monomer.
12. The radiation-curable liquid ink composition of claim 11 , wherein the polymerizable monomer is an acrylate monomer.
13. The radiation-curable liquid ink composition of claim 10 , further comprising a diluent.
14. The radiation-curable liquid ink composition of claim 13 , wherein the diluent is a mono-functional or di-functional monomer.
15. The radiation-curable liquid ink composition of claim 14 , wherein the polymerizable monomer is a multi-functional monomer.
16. The radiation-curable liquid ink composition of claim 15 , wherein polymerizable monomer is an acrylate monomer.
17. The radiation-curable liquid ink composition of claim 10 , wherein the radiation-curable liquid ink composition has a viscosity ranging from about 1 centipoise to about 50 centipoise.
18. A printing method, comprising:
printing a radiation-curable hot melt ink composition on a substrate to form an image, the composition comprising a colorant; a polymerizable monomer; and a photoinitiating system comprising 0.5-1.5% by weight of an aromatic ketone photoinitiator, 2-10% by weight of an amine synergist, 3-8% by weight of a second photoinitiator different than the aromatic ketone photoinitiator and capable of undergoing alpha cleavage, and 0.5-1.5% by weight of a photosensitizer; and
irradiating the image.
19. A printing method, comprising the steps of:
printing a radiation-curable liquid ink composition on a substrate to form an image, the composition comprising a colorant; a polymerizable monomer; and a photoinitiating system comprising 2-4% by weight of an aromatic ketone photoinitiator, 5-10% by weight of an amine synergist, 5-10% by weight of a second photoinitiator different than the aromatic ketone photoinitiator and capable of undergoing alpha cleavage, and 2-4% by weight of a photosensitizer; and
irradiating the image.