Radiation-curable high gloss overprint varnish compositions

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 michael donor, and

ii. a michael acceptor and

B. at least one of the following,

i. a diluent,

ii. a photoinitiator,

iii. an adhesion promoter,

iv. a defoaming agent,

v. a flow and leveling aid, and

vi. an amine synergist,

wherein the high gloss overprint varnish composition has a viscosity of less than about 500 centipoise:

2 . The composition of claim 1 , wherein the Michael donor is a β-dicarbonyl compound.

3 . The composition of claim 1 , wherein the Michael acceptor is an acrylate monomer, oligomer, polymer or mixture thereof.

4 . 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.

5 . The composition of claim 1 , wherein the Michael acceptor is selected from the group consisting of monoacrylates, diacrylates, triacrylates, tetraacrylates and mixtures thereof.

6 . 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.

7 . The composition of claim 1 , wherein the Michael donor is modified to contain a pendant Type I photoactive and/or Type II photoactive moiety.

8 . The composition of claim 1 , wherein the Michael acceptor is modified to contain a pendant Type I photoactive and/or Type II photoactive moiety.

9 . The composition of claim 1 , wherein the Michael addition resin is present in an amount from about 60 wt % to about 98 wt %.

10 . The composition of claim 1 , wherein the Michael addition resin is present in an amount from about 80 wt % to about 98 wt %.

11 . The composition of claim 1 , containing an adhesion promoter.

12 . The composition of claim 1 , containing a reactive diluent.

13 . The composition of claim 1 , containing a reactive diluent, a photoinitiator, an amine synergist and a flow and leveling aid.

14 . The composition of claim 1 , containing a reactive diluent, a defoaming agent and a flow and leveling aid.

15 . The composition of claim 1 , containing a reactive diluent, an amine synergist and a photoinitiator.

16 . 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 Michael donor, and

ii. a Michael acceptor,

wherein the crosslinked reaction product has a gloss of at least 60.

17 . The coated article of claim 16 , wherein the Michael addition resin has a gloss of at least 80.

18 . The coated article of claim 16 , further comprising one or more,

A. diluent,

B. photoinitiator,

C. adhesion promoter,

D. defoaming agent,

E. flow and leveling aid, or

F. amine synergist.

19 . The coated article of claim 16 , wherein the Michael addition resin is modified to contain a pendant Type I photoactive and/or Type II photoactive moiety.

20 . The coated article of claim 16 , wherein the Michael donor is modified to contain a pendant Type I photoactive and/or Type II photoactive moiety.

21 . The coated article of claim 16 , wherein the Michael acceptor is modified to contain a pendant Type I photoactive and/or Type II photoactive moiety.

22 . The coated article of claim 16 , 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.

23 . The coated article of claim 16 , wherein the Michael acceptor is selected from the group consisting of monoacrylates, diacrylates, triacrylates, tetraacrylates and mixtures thereof.

24 . The coated article of claim 16 , wherein the Michael addition resin is cured via exposure to actinic radiation.