Inkjet ink binder and inkjet ink composition

Abstract

An inkjet ink binder including an aqueous dispersion of polymer particles, the polymer including, as polymerized units, (a) from 0 to 1 wt. % monoethylenically unsaturated acid monomer, based on polymer weight; and (b) monomer of the formula CH 2 ═C(R1)—CON(R2)(R3) wherein R1═H, CH 3 or C 2 H 5 and R2 and R3 are independently selected from C1-C6 saturated alkyl and cycloalkyl groups; and wherein the total of (a) and (b) is at least 0.1 wt % monomer based on the polymer weight. The binder may be a copolymer of ethyl acrylate and acrylamide. An inkjet ink composition including the inkjet ink binder, a colorant, and a liquid medium is also provided.

1 . An inkjet ink binder comprising an aqueous dispersion of polymer particles, said polymer comprising, as polymerized units, (a) from 0 to 1 wt. % monoethylenically unsaturated acid monomer, based on polymer weight; and 
 (b) monomer of the formula      CH 2 ═C(R1)—CON(R2)(R3)    wherein R1═H, CH 3  or C 2 H 5  and R2 and R3 are independently selected from C1-C6 saturated alkyl and cycloalkyl groups; and wherein the total of (a) and (b) is at least 0.1 wt % monomer based on said polymer weight.    
     
     
         2 . The inkjet ink binder of  claim 1  further comprising, as polymerized units, from 10 to 98 wt %, C1-C3 alkyl acrylate.  
     
     
         3 . The inkjet ink binder of  claim 1  wherein monomer (b) is selected from the group consisting of acrylamide, methacrylamide, ethacrylamide, N-methyl acrylamide, N-ethyl methacrylamide, N-t-butyl acrylamide, N,N-dimethyl acrylamide, N-cyclohexyl acrylamide, and combinations thereof.  
     
     
         4 . The inkjet ink binder of  claim 1  wherein the glass transition temperature of the binder is in the range of −40° C. to 120° C.  
     
     
         5 . The inkjet ink binder of  claim 1  wherein the number average particle diameter of the polymer particles is from 150 to 400 nm, as measured by Capillary Hydrodynamic Fractionation (“CHDF”).