Radiation-curable high gloss overprint varnish compositions

Abstract

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 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.