# US 8,771,787 B2 · Ink for digital offset printing applications > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,771,787 B2 - Document ID: US8771787B2 - Status: Granted - Kind: B2 - Application number: 13/474,138 - Filed: 2012-05-17 - Published: 2013-11-21 - Granted: 2014-07-08 - Earliest claimed: 2012-05-17 - Assignees: Xerox Corporation; Palo Alto Research Center Incorporated - Applicants: Marcel P. Breton; Frank Ping-Hay Lee; Aurelian Valeriu Magdalinis; Bing R. Hsieh; Stephan Drappel; Timothy D. Stowe; C. Geoffrey Allen; Peter Gordon Odell - Inventors: Marcel P. Breton; Frank Ping-Hay Lee; Aurelian Valeriu Magdalinis; Bing R. Hsieh; Stephan Drappel; Timothy D. Stowe; C. Geoffrey Allen; Peter Gordon Odell - Web page: https://patentgrep.com/patent/US8771787B2 ## CPC - B41M 1/08: Dry printing - B41N 3/08: Damping; Neutralising or similar differentiation treatments for lithographic printing formes; {Gumming or finishing solutions, fountain solutions, correction or deletion fluids, or on-press development (treatment of materials containing silver salts G03F7/063; developers per se for processing photosensitive materials G03F7/32)} - C09D 11/101: Inks specially adapted for printing processes involving curing by wave energy or particle radiation, e.g. with UV-curing following the printing - B41M: PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING, (correction of typographical errors B41J; processes for applying transfer pictures or the like B44C1/16; fluid media for correction of typographical errors by coating C09D10/00; printing textiles D06P) - B41N: PRINTING PLATES OR FOILS (photosensitive material G03); MATERIALS FOR SURFACES USED IN PRINTING MACHINES FOR PRINTING, INKING, DAMPING, OR THE LIKE; PREPARING SUCH SURFACES FOR USE AND CONSERVING THEM - C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D) ## Abstract An ink composition useful for digital offset printing applications comprises a colorant and a plurality of curable compounds. The compounds have Hansen solubility parameters as described herein, and the resulting ink composition is both compatible with certain dampening fluids and has certain rheological properties, including a low viscosity. ## Claims ### Claim 1 An ink composition comprising a plurality of curable compounds, wherein the ink composition has a volume average Hansen fractional dispersion force parameter (fd) of from about 0.4 to about 0.62, a volume average Hansen fractional polar parameter (fp) of from about 0.1 to about 0.3, and a volume average Hansen fractional hydrogen bonding parameter (fh) of from about 0.2 to about 0.4, wherein the plurality of curable compounds includes a tetrafunctional acrylated polyester. ### Claim 2 (depends on 1) The ink composition of claim 1, wherein the plurality of curable compounds includes a polyethylene glycol diacrylate. ### Claim 3 (depends on 1) The ink composition of claim 1, wherein the plurality of curable compounds includes a tripropylene glycol diacrylate. ### Claim 4 (depends on 1) The ink composition of claim 1, further comprising from about 0.2 to about 5 wt % of a polyether modified acryl functional polydimethylsiloxane. ### Claim 5 (depends on 1) The ink composition of claim 1, wherein the plurality of curable compounds includes, based on the total weight of the ink composition: from about 40 to about 55 wt % of a tetrafunctional acrylated polyester; from about 9 to about 11 wt % of a polyethylene glycol diacrylate; and from 0 to about 11 wt % of a tripropylene glycol diacrylate. ### Claim 6 (depends on 1) The ink composition of claim 1, further comprising from greater than 0 to about 20 wt % of an aliphatic acrylate ester. ### Claim 7 (depends on 1) The ink composition of claim 1, further comprising at least one additive selected from the group consisting of dispersants, thickening agents, photoinitiators, and stabilizers. ### Claim 8 (depends on 1) The ink composition of claim 1, further comprising, based on the total weight of the ink composition: from about 2 to about 10 wt % of a dispersant; from about 0.2 to about 5 wt % of a thickening agent; from 0 to about 10 wt % of a photoinitiator; and from about 0.1 to about 1 wt % of a thermal stabilizer. ### Claim 9 (depends on 1) The ink composition of claim 1, wherein the ink composition has a viscosity of from about 5,000 to about 1,000,000 centipoise at 25° C. and a shear rate of 5 sec−1. ### Claim 10 (depends on 1) The ink composition of claim 1, wherein the ink composition has a shear thinning index (50/5) at 25° C. of from about 0.10 to about 0.60. ### Claim 11 (depends on 1) The ink composition of claim 1, wherein the ink composition has a surface tension of from about 25 dynes/cm to about 40 dynes/cm at 25° C. ### Claim 12 (depends on 1) The ink composition of claim 1, wherein the plurality of curable compounds comprises more than 50 wt % of the ink composition. ### Claim 13 (depends on 1) The ink composition of claim 1, further comprising a colorant. ### Claim 14 (depends on 13) The ink composition of claim 13, containing from about 10 to about 40 wt % of the colorant, based on the total weight of the ink composition. ### Claim 15 (depends on 1) The ink composition of claim 1, wherein one or more of the curable compounds are crosslinkable. ### Claim 16 A process for variable lithographic printing, comprising: applying a dampening fluid to an imaging member surface; forming a latent image by evaporating the dampening fluid from selective locations on the imaging member surface to form hydrophobic non-image areas and hydrophilic image areas; developing the latent image by applying an ink composition comprising an ink component to the hydrophilic image areas; and transferring the developed latent image to a receiving substrate; wherein the ink composition comprises a plurality of curable compounds, the ink composition having a volume average Hansen fractional dispersion force parameter (fd) of from about 0.4 to about 0.62, a volume average Hansen fractional polar parameter (fp) of from about 0.1 to about 0.3, and a volume average Hansen fractional hydrogen bonding parameter (fh) of from about 0.2 to about 0.4, wherein the plurality of curable compounds includes a tetrafunctional acrylated polyester. ### Claim 17 (depends on 16) The process of claim 16, wherein the ink composition contains at least one curable compound which has a radius of interaction greater than 16 with the dampening fluid. ### Claim 18 (depends on 16) The process of claim 16, wherein one or more of the curable compounds are crosslinkable. ### Claim 19 An ink composition comprising a plurality of curable compounds, wherein each curable compound has a Hansen fractional dispersion force parameter (fd) of from about 0.4 to about 0.62, a Hansen fractional polar parameter (fp) of from about 0.1 to about 0.3, and a Hansen fractional hydrogen bonding parameter (fh) of from about 0.2 to about 0.4, wherein the plurality of curable compounds includes a tetrafunctional acrylated polyester.