Aqueous dispersible polymer inks

Abstract

An ink composition or ink concentrate for variable data lithographic printing or ink jet printing that uses an intermediate substrate, includes nano-particles, wherein each nano-particle is a polymer or a polymer blend of polymers; the polymer or polymers of the polymer blend are water dispersible at temperatures below 100 degrees Celsius; solids content of the ink composition is in an amount of greater than 25 percent by total weight; and the ink composition has a viscosity of about 100 centipoise to about 1,000 centipoise in the temperature range of 20 degrees Celsius to 50 degrees Celsius.

What is claimed is: 
     
         1 . An ink composition for variable data offset printing or an ink jet printing process that uses an intermediate substrate, comprising:
 nano-particles, wherein each nano-particle is a polymer or a polymer blend of polymers, and   optionally one or more mixtures of the following: inorganic particles, silica, pigment, salts, bioside, buffer, or humectant,   wherein the polymer or the polymers of the polymer blend are water dispersible at temperatures less than 100 degrees Celsius,   wherein the total solids content of the ink composition is an amount in a range of about 25% or greater by total weight of the ink composition,   wherein the polymer or the polymer blend comprises a sulfonated polyester, and   wherein the ink composition has a viscosity of about 100 centipoise to about 1,000 centipoise in the temperature range of 20 degrees Celsius to 50 degrees Celsius.   
     
     
         2 . The ink composition of  claim 1 , wherein the polymer comprises a component derived from monomers selected from the group consisting of glycols, multifunctional glycols, alcohols, multifunctional alcohols, acids, and salts thereof, and
 wherein the polymer blend comprises a component selected from the group consisting of carboxyl-polyester and polyester.   
     
     
         3 . The ink composition of  claim 1 , wherein the polymer or the polymers of the polymer blend contains a portion that is water soluble in an amount less than 10%, and is soluble in a non-aqueous liquid vehicle in an amount less than 30%, at a temperature between 20 and 50 degrees Celsius. 
     
     
         4 . The ink composition of  claim 1 , wherein the polymer or the polymers of the polymer blend are substantially soluble at temperatures above 70 to 95 degrees Celsius. 
     
     
         5 . The composition of  claim 1 , wherein the polymer or the polymer blend has a critical phase separation temperature of about 50 degrees Celsius to about 90 degrees Celsius. 
     
     
         6 . The ink composition of  claim 1 , wherein the polymer or the polymers of the polymer blend comprises an unsaturated functional group. 
     
     
         7 . The ink composition of  claim 1 , comprising:
 a co-solvent, the co-solvent having a surface tension of about 15 dynes/centimeter to about 40 dynes/centimeter, the co-solvent being selected from the group comprising alcohols, glycols, alkyl pyrrolidinones, isopropanol, ketones methyl ethyl ketone, amino alcohol and DMSO.   
     
     
         8 . The ink composition of  claim 1 , wherein the nano-particles are less than 200 nm, or mixtures of nano-particles forming bimodal or trimodal distributions. 
     
     
         9 . The ink composition of  claim 1 , further comprising:
 a self-dispersing pigment of a particle size between 5 to 200 nm, wherein the pigment is chemically modified or resin encapsulated.   
     
     
         10 . The ink composition of  claim 1 , further comprising a self-dispersing pigment that is encapsulated by, or aggregated with the polymer or the polymer blend, thereby forming a nano-particle. 
     
     
         11 . The composition of  claim 9 , wherein the resin that is used to encapsulate the pigment is between 9 percent and 66 percent of the combined weight of the pigment and the encapsulating resin. 
     
     
         12 . The composition of  claim 1 , wherein the ink composition has a viscosity of ink after loss of 0 to 80 percent of liquid vehicle is between 10,000 centipoise and 1,000,000,000 centipoise at temperatures between 10 degrees Celsius to about 90 degrees Celsius. 
     
     
         13 . The composition of  claim 1 , wherein the surface tension of the ink is between 15 and 40 dynes/centimeter at 25 degrees C., or over the temperature range between 20 to 50 degrees C. 
     
     
         14 . The ink composition of  claim 1 , wherein the sulfonated polyester is copoly(1,2-propylene-dipropylene-terephthalate)-copoly(1,2-propylene-dipropylene-5-sodiosulfoisophthalate). 
     
     
         15 . A method of printing using high solids content inks, comprising:
 providing an ink comprising water and nano-particles, wherein each nano-particle is a polymer or a polymer blend of polymers; and   applying the ink to an intermediate transfer member, wherein the intermediate transfer member has a surface comprising silicone or fluorosilicone,   wherein the polymer or polymers of the polymer blend are water dispersible,   wherein a solids content of the ink is in an amount of about 5% to about 50% by weight by total weight of the ink, and   wherein the polymer or the polymer blend comprises a sulfonated polyester,   wherein the ink has a viscosity of about 100 centipoise to about 1000 centipoise in the temperature range of 20 degrees Celsius to 50 degrees Celsius.   
     
     
         16 . The method of  claim 15 , wherein the step of the applying the ink further comprises:
 applying the ink at an ink temperature above the upper critical phase separation temperature of the polymer or the polymer blend, the upper critical phase separation temperature being about 30 degrees Celsius to about 50 degrees Celsius;   cooling the ink on the intermediate transfer member; and   transferring the ink from the intermediate transfer member to a printable substrate.   
     
     
         17 . The method of  claim 16 , wherein the printable substrate is an imaging member of an ink-based digital printing system. 
     
     
         18 . The method of  claim 15 , wherein a film of the ink on the intermediate transfer member has a surface tension of about 15 dynes/centimeter to about 40 dynes/centimeter. 
     
     
         19 . The method of  claim 15 , comprising:
 diluting the ink with water before the step of applying, whereby the solid content of the ink is between 5% and 25% by weight, and   wherein, the step of applying the ink to an intermediate transfer member further comprises jetting the diluted ink from an inkjet printhead.   
     
     
         20 . An ink composition for variable data offset printing or an ink jet printing process that uses an intermediate substrate, comprising:
 nano-particles, wherein each nano-particle is a polymer or a polymer blend of polymers,   wherein the polymer or the polymers of the polymer blend are water dispersible at temperatures less than 100 degrees Celsius,   wherein the total solids content of the ink composition is an amount in a range of about 4% to about 25% by total weight of the ink composition,   wherein the polymer or the polymer blend comprises a sulfonated polyester,   wherein the ink composition has a viscosity of about 100 centipoise to about 1000 centipoise in the temperature range of 20 degrees Celsius to 50 degrees Celsius.