Patent ID: 8133935

Claim:
An ink-jet ink substantially free of water and volatile organic solvents comprising at least one monofunctional (meth)acrylate monomer; at least one monofunctional monomer selected from the group consisting of an N-vinyl amide, an N-acryloyl amine and mixtures thereof; at least one radical photoinitiator; and at least one colouring agent; wherein the ink has a viscosity of less than 100 mPas at 25° C., and contains no more than 15 wt % of multifunctional monomers based on the total weight of the ink; and wherein the total amount of the at least one monofunctional (meth)acrylate monomer and the at least one monomer selected from the group consisting of an N-vinyl amide, an N-acryloyl amine and mixtures thereof in combination is at least 60 wt % based on the total weight of the ink, and the molar ratio of the at least one monofunctional (meth)acrylate monomer to the at least one monomer selected from the group consisting of an N-vinyl amide monomer, an N-acryloyl amine and mixtures thereof is from 1.1 to 3.5, and further wherein said ink-jet ink has a higher cure speed than a cure speed of an ink-jet ink which comprises only one of the at least one monofunctional (meth)acrylate monomer and the at least one monofunctional N-vinyl amide and/or N-acryloyl amine monomer.