Radiation-curable lithographic inks from multifunctional acrylate oligomers
View Patent ↗The present invention relates generally to radiation-curable ink formulations, and particularly, but not by way of limitation, to a family of radiation-curable ink formulations specifically for lithographic printing applications. The inventive ink formulations are based on multifunctional acrylate resins formed by the reaction of acrylate monomers and oligomers with β-keto esters (e.g., acetoacetates), β-diketones (e.g., 2,4-pentanedione), β-keto amides (e.g., acetoacetanilide, acetoacetamide), and/or other β-dicarbonyl compounds that can participate in Michael addition reactions.
1. A lithographic ink comprising:
a pigment dispersion;
a let-down resin comprising:
a β-dicarbonyl Michael donor;
at least one multi-functional acrylate oligomer; and
at least one secondary amine, wherein
said resin is insoluble in water,
said resin forms an emulsion with water, and
said uncrosslinked resin has a viscosity of from about 100 to about 500 poise;
a foam control agent; and optionally
a monomer.
2. The UV-curable Michael resin composition, according to claim 1 , wherein said β-dicarbonyl monomer is selected from the group consisting of β-keto esters, β-diketones, β-keto amides, and cyanoacetates.
3. The UV-curable Michael resin composition, according to claim 2 , wherein a preferred β-dicarbonyl monomer is 2-methoxyethyl acetoacetate.
4. The UV-curable Michael resin composition, according to claim 1 , wherein said multi-functional acrylate oligomer is selected from the group consisting of polyester, epoxy and urethane acrylates.
5. The UV-curable Michael resin composition, according to claim 4 , wherein a preferred acrylate oligomer is an epoxy acrylate.
6. The UV-curable Michael resin composition, according to claim 5 , wherein a preferred epoxy acrylate is a low viscosity epoxy acrylate.
7. The lithographic ink according to claim 1 , further comprising a photoinitiator.
8. A method of lithographic printing comprising providing the lithographic ink of claim 1 to a lithographic press.
9. The method of lithographic printing, according to claim 8 , further comprising applying said ink to a substrate using said press and curing said ink.
10. A substrate coated with the lithographic ink of claim 1 .
11. A lithographic press containing the lithographic ink of claim 1 .