Radiation-curable high gloss overprint varnish compositions
View Patent ↗The present invention relates to radiation-curable overprint varnishes for printed substrates based on multifunctional, uncrosslinked, liquid Michael addition resins. The compositions are UV-curable with little or no photoinitiator present.
1. A high gloss, UV curable overprint varnish composition, comprising:
A. a liquid Michael addition resin present in amounts up to 99 wt. % based on the total weight of the overprint varnish composition, comprising the uncrosslinked reaction product of,
i. a β-dicarbonyl Michael donor,
ii. at least one multi-functional acrylate oligomer incorporated with mono-functional acrylate, and
iii. at least one amine synergist; and
B. at least one of the following,
i. a diluent,
ii. a photoinitiator,
iii. an adhesion promoter,
iv. a defoaming agent, and
v. a flow and leveling aid,
wherein the high gloss overprint varnish composition has a viscosity of less than about 500 centipolse.
2. The composition of claim 1 , wherein the Michael donor is selected from the group consisting of a β-ketoester, a β-diketone, a β-ketoamide, a β-ketoanilide and mixtures thereof.
3. The composition of claim 1 , wherein the multi-functional acrylate oligomer is selected from the group consisting of monoacrylates, diacrylates, triacrylates, tetraacrylates and mixtures thereof.
4. The composition of claim 1 , wherein the Michael addition resin is modified to contain a pendant Type I photoactive and/or Type II photoactive moiety.
5. The composition of claim 1 , wherein the Michael donor is modified to contain a pendant Type I photoactive and/or Type II photoactive moiety.
6. The composition of claim 1 , wherein the Michael acceptor is modified to contain a pendant Type I photoactive and/or Type II photoactive moiety.
7. The composition of claim 1 , wherein the Michael addition resin is present in an amount from about 60 wt % to about 98 wt %.
8. The composition of claim 1 , wherein the Michael addition resin is present in an amount from about 80 wt % to about 98 wt %.
9. The composition of claim 1 , containing an adhesion promoter.
10. The composition of claim 1 , containing a reactive diluent.
11. The composition of claim 1 , containing a reactive diluent, a photoinitiator, and a flow and leveling aid.
12. The composition of claim 1 , containing a reactive diluent, a defoaming agent and a flow and leveling aid.
13. The composition of claim 1 , containing a reactive diluent and a photoinitiator.
14. A coated article, comprising A. a substrate having at least one printed surface, and B. a high gloss overprint varnish on at least one printed surface of the substrate, comprising the cured, cross-linked reaction product of a liquid Michael addition resin, comprising: i. a β-dicarbonyl Michael donor, ii. at least one multi-functional acrylate oligomer incorporated with mono-functional acrylate and, iii. at least one amine synergist wherein the crosslinked reaction product has a gloss of at least 60.
15. The coated article of claim 14 , wherein the Michael addition resin has a glass of at least 80.
16. The coated article of claim 14 , further comprising one or more, A. diluent, B. photoinitiator, C. adhesion promoter, D. defoaming agent, or E. flow and leveling aid.
17. The coated article of claim 14 , wherein the Michael addition resin is modified to contain a pendant Type I photoactive and/or Type II photoactive moiety.
18. The coated article of claim 14 , wherein the Michael donor is modified to contain a pendant Type I photoactive and/or Type II photoactive moiety.
19. The coated article of claim 14 , wherein the Michael acceptor is modified to contain a pendant Type I photoactive and/or Type II photoactive moiety.
20. The coated article of claim 14 , wherein the Michael donor is selected from the group consisting of a β-ketoester, a β-diketone, a β-ketoamide, a β-ketoanilide and mixtures thereof.
21. The coated article of claim 14 , wherein the Michael addition resin is cured via exposure to actinic radiation.