Acrylate Ink Compositions For Ink-Based Digital Lithographic Printing

Abstract

Compatible acrylate ink sets include an acrylate ink composition having 30% or less by weight pigment, 10% or less dispersant, between 40% and 80% acrylate, 12% or less photoinitiator, a viscosity between 5×10 5 and 3×10 7 cps at 35° C., and a 60 second tack between 25 and 50 g-m at 35° C.

1 . An acrylate ink composition comprising:
 a tetrafunctional polyester acrylate oligomer;   a polyester acrylate oligomer that is different than the tetrafunctional polyester acrylate oligomer;   a pigment;   an optional dispersant; and   an optional photoinitiator.   
     
     
         2 . The ink composition of  claim 1 , further comprising:
 at least one member of the group consisting of a propoxylated trimethololpropane triacrylate monomer and an ethoxylated trimethylolpropane triacrylate monomer.   
     
     
         3 . The ink composition of  claim 1 , further comprising:
 at least one member of the group consisting of a propoxylated trimethololpropane triacrylate monomer, an ethoxylated trimethylolpropane triacrylate monomer, and a monomer having a functionality greater than or equal to 4.   
     
     
         4 . The ink composition of  claim 1 , wherein a viscosity of the ink composition is between 5×10 5  and 3×10 7  cps at 35° C. 
     
     
         5 . The ink composition of  claim 1 , wherein a 60 second tack of the ink composition is between 25 and 50 g-m at 35° C. 
     
     
         6 . The ink composition of  claim 1 , wherein the ink composition comprises between 40% and 50% by weight acrylate, based on a total weight of the ink composition;
 30% or less by weight pigment, based on the total weight of the ink composition;   10% or less by weight dispersant, based on the total weight of the ink composition; and   12% or less by weight photoinitiator, based on the total weight of the ink composition.   
     
     
         7 . The ink composition of  claim 1 , further comprising:
 a stabilizer; and   a rheology modifier;   wherein the ink composition comprises:   between 10% and 20% pigment;   between 2% and 10% dispersant;   between 40% and 50% acrylate;   10% or less photoinitiator;   0.4% or less stabilizer;   between 1% and 5% rheology modifier;   wherein a viscosity of the ink composition is between 8×10 5  and 2×10 7  cps at 35° C.; and   wherein a 60 second tack of the ink composition is between 35 and 45 g-m at 35° C.   
     
     
         8 . The ink composition of  claim 1 , further comprising:
 a stabilizer; and   a rheology modifier;   wherein the ink composition comprises:   between 12% and 18% pigment;   between 4% and 8% dispersant;   between 40% and 50% acrylate;   between 5% and 10% less photoinitiator;   between 0.1% and 0.3% stabilizer;   3% or less rheology modifier;   wherein a viscosity of the ink composition is between 1×10 6  and 1×10 7  cps at 35° C.; and   wherein a 60 second tack of the ink composition is about 40 g-m at 35° C.   
     
     
         9 . The ink composition of  claim 1 , wherein the photoinitiator is a free-radical photoinitiator. 
     
     
         10 . The ink composition of  claim 1 , wherein the pigment is one of a cyan pigment, a magenta pigment, a yellow pigment, or a black pigment. 
     
     
         11 . A set of compatible acrylate ink compositions comprising:
 a first acrylate ink composition comprising a first pigment;   a second acrylate ink composition comprising a second pigment;   wherein each of the acrylate ink compositions comprises:   a tetrafunctional polyester acrylate oligomer;   a polyester acrylate oligomer that is different than the tetrafunctional polyester acrylate oligomer;   an optional dispersant; and   an optional photoinitiator.   
     
     
         12 . The set of compatible acrylate ink compositions of  claim 11 , wherein each of acrylate ink compositions further comprises:
 at least one member of the group consisting of a propoxylated trimethololpropane triacrylate monomer and an ethoxylated trimethylolpropane triacrylate monomer.   
     
     
         13 . The set of compatible acrylate ink compositions of  claim 11 , wherein each of acrylate ink compositions further comprises:
 at least one member of the group consisting of a propoxylated trimethololpropane triacrylate monomer, an ethoxylated trimethylolpropane triacrylate monomer, and a monomer having a functionality greater than or equal to 4.   
     
     
         14 . The set of compatible acrylate ink compositions of  claim 11 , wherein a viscosity of each of the ink compositions is between 5×10 5  and 3×10 7  cps at 35° C. 
     
     
         15 . The set of compatible acrylate ink compositions of  claim 11 , wherein a 60 second tack of each of the ink composition is between 25 and 50 g-m at 35° C. 
     
     
         16 . The set of compatible acrylate ink compositions of  claim 11 , wherein each of the ink compositions comprises:
 between 40% and 50% by weight acrylate, based on a total weight of the ink composition;   30% or less by weight pigment, based on the total weight of the ink composition;   10% or less by weight dispersant, based on the total weight of the ink composition; and   12% or less by weight photoinitiator, based on the total weight of the ink composition.   
     
     
         17 . The set of compatible acrylate ink compositions of  claim 11 , wherein each of the ink compositions further comprises:
 a stabilizer; and   a rheology modifier.   
     
     
         18 . The set of compatible acrylate ink compositions of  claim 11 , wherein each of the ink compositions further comprises:
 a rheology modifier; and   wherein each of the ink compositions comprises:   between 12% and 18% pigment;   between 4% and 8% dispersant;   between 40% and 50% acrylate;   between 5% and 10% less photoinitiator;   between 0.1% and 0.3% stabilizer;   3% or less rheology modifier;   wherein a viscosity of each ink composition is between 1×10 6  and 1×10 7  cps at 35° C.; and   wherein a 60 second tack of each ink composition is about 40 g-m at 35° C.   
     
     
         19 . The set of compatible acrylate ink compositions of  claim 11 , wherein the photoinitiator is a free-radical photoinitiator. 
     
     
         20 . The set of compatible acrylate ink compositions of  claim 11 , wherein the first pigment is one of a cyan pigment, a magenta pigment, and a yellow pigment; and
 wherein the second pigment is a black pigment.