Radiation-curable inks for flexographic and screen-printing applications 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 flexographic and screen 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 Michael flexo let-down resin comprising: about 18.4 wt. % trimethyolpropane ethoxytriacrylate (TMPEOTA) about 59.0 wt. % dipropylene glycol diacrylate; about 4.9 wt. % piperidine; and about 15.3 wt. % methoxyethyl acetoacetate (MEAA).
2. A UV-curable, flexographic ink comprising: from about 10 parts, by weight, to about 80 parts, by weight, of a Michael flexo let-down resin and from about 10 parts, by weight, to about 50 parts, by weight, of a pigment dispersion, wherein the Michael flexo let-down resin comprises:
a monomer or oligomer serving the function of pigment wetting;
a monomer serving the function of viscosity control;
a monomer serving the function of adhesion promotion;
a monomer serving the function of cure enhancement selected from the group consisting of amine-modified polyether, polyester, epoxy or urethane acrylates, primary and secondary amines and amino acrylates; and
a monomer serving the function of Michael donor providing a photolabile chromophore and wherein said pigment dispersion comprises a resin formed from a polyacrylate Michael acceptor and a dicarbonyl Michael donor and a pigment.
3. The UV-curable, flexographic ink, according to claim 2 , further comprising up to about 10 parts by weight of an adhesion monomer.
4. The UV-curable, flexographic ink, according to claim 3 , wherein said adhesion monomer is selected from the group consisting of N-vinyl caprolactam, N-vinyl pyrrolidone, and vinyl ether esters.
5. The UV-curable, flexographic ink, according to claim 4 , wherein said adhesion monomer is N-vinyl caprolactam.
6. The UV-curable, flexographic ink, according to claim 2 , further comprising up to about 5 parts by weight of a reactive defoamer.
7. The UV-curable, flexographic ink, according to claim 6 , wherein said reactive defoamer is selected from the group consisting of an acrylated defoamer.
8. The UV-curable, flexographic ink, according to claim 2 , further comprising up to about 1 part by weight of a silicone defoamer.
9. The UV-curable, flexographic ink, according to claim 8 , wherein said silicone defoamer is selected from the group consisting of silicones and siloxane copolymers.
10. The UV-curable, flexographic ink, according to claim 2 , further comprising up to about 10 parts by weight of a photoinitiator.
11. A method of using a UV-curable, flexographic ink, the method comprising: applying the UV-curable, flexographic ink of claim 2 , to a substrate; and curing said ink.
12. The method of using a UV-curable, flexographic ink, according to claim 11 , wherein said curing comprises irradiating said ink with an effective amount of actinic light.
13. The method of using a UV-curable, flexographic ink, according to claim 11 , further comprising: providing a flexographic printing press; and applying said ink to said substrate using said press.
14. A printed substrate comprising a printable substrate having applied thereto the UV-curable, flexographic ink of claim 2 .
15. The printed substrate, according to claim 14 , wherein said ink is cured.
16. A Michael screen let-down resin for a screen-print ink, said Michael screen let-down resin comprising: a monomer serving the function of pigment wetting; a monomer serving the function of viscosity control; a monomer serving the function of adhesion promotion; a monomer serving the function of cure enhancement selected from the group consisting of amine-modified polyether, polyester, epoxy or urethane acrylates, primary and secondary amines, and amino acrylates; a monomer serving the function of Michael donor providing a photolabile chromophore, wherein the adhesion promotion monomer is phenoxyethyl acetate.
17. A Michael screen let-down resin for a screen-print ink, said Michael screen let-down resin comprising: a monomer serving the function of pigment wetting; a monomer serving the function of viscosity control; a monomer serving the function of adhesion promotion; a monomer serving the function of cure enhancement selected from the group consisting of amine-modified polyether, polyester, epoxy or urethane acrylates, primary and secondary amines and amino acrylates; a monomer serving the function of Michael donor providing a photolabile chromophore, an further comprising: about 28.6 wt. % trimethyolpropane ethoxytriacrylate (TMPEOTA) TMPEOTA; about 38.8 wt. % DPGDA; about 7.7 wt. % phenoxyethyl acetate about 6.9% dodecyl acetoacetate; about 13.7 wt. % acetoacetanilide; and about 1.8 wt. % piperidine.
18. A UV-curable, screen ink comprising: from about 20 parts, by weight, to about 80 parts, by weight, of a Michael screen let-down resin; and from about 10 parts, by weight, to about 50 parts, by weight, of a pigment dispersion, wherein the Michael let-down resin comprises a monomer serving the function of pigment wetting; a monomer serving the function of viscosity control; a monomer serving the function of adhesion promotion; a monomer serving the function of cure enhancement selected from the group consisting of amine-modified polyether, polyester, epoxy or urethane acrylates, primary and secondary amines, and amino acrylates; a monomer serving the function of Michael donor providing a photolabile chromophore and wherein said pigment dispersion comprises a resin formed from a polyacrylate Michael acceptor and a dicarbonyl Michael donor and a pigment.
19. The UV-curable, screen ink, according to claim 18 , further comprising up to about 10 parts by weight of an adhesion monomer.
20. The UV-curable, screen ink, according to claim 19 , wherein said adhesion monomer is selected from the group consisting of N-vinyl caprolactam, N-vinyl pyrrolidone, and vinyl ether esters.
21. The UV-curable, screen ink, according to claim 20 , wherein said adhesion monomer is N-vinyl caprolactam.
22. The UV-curable, screen ink, according to claim 18 , further comprising up to about 5 part by weight of a reactive defoamer.
23. The UV-curable, screen ink, according to claim 22 , wherein said reactive defoamer is a modified polyacrylate.
24. The UV-curable, screen ink, according to claim 18 , further comprising up to about 1 part by weight of a silicone defoamer.
25. The UV-curable, screen ink, according to claim 24 , wherein said silicone defoamer is selected from the group consisting of silicones and siloxane copolymers.
26. The UV-curable, screen ink, according to claim 18 , further comprising up to about 10 parts by weight of a photoinitiator.
27. A method of using a UV-curable, screen ink, the method comprising: applying the UV-curable, screen ink of claim 18 , to a substrate; and curing said ink.
28. The method of using a UV-curable, screen ink, according to claim 27 , wherein curing comprises irradiating said ink with an effective amount of actinic light.
29. The method of using a UV-curable, screen ink, according to claim 27 , further comprising: providing a screen printing press; and applying said ink to said substrate using said press.
30. A printed substrate comprising a printable substrate having applied thereto the UV-curable, screen ink, according to claim 18 .
31. The printed substrate, according to claim 30 , wherein said ink is cured.
32. A writing instrument or printer having the UV-curable, screen ink of claim 18 , stored therein.
33. A writing instrument or printer having the UV-curable, flexo ink of claim 2 , stored therein.
34. A writing instrument or printer having the Michael flexo let-down resin of claim 1 , stored therein.
35. A writing instrument or printer having the Michael screen let-down resin of claim 16 , stored therein.
36. A writing instrument or printer having the Michael screen let-down resin of claim 17 , stored therein.