Aqueous Ink Composition Comprising A Polymer Additive

Abstract

An aqueous ink composition including water; an optional co-solvent; an optional colorant; a polyester; and a polymer additive, wherein the polymer additive is selected from a member of the group consisting of styrene-butadiene, acrylonitrile-butadiene, acrylonitrile-butadiene-styrene, and combinations thereof. A process of digital offset printing including applying an ink composition onto a re-imageable imaging member surface at an ink take up temperature, the re-imageable imaging member having dampening fluid disposed thereon; forming an ink image; transferring the ink image from the re-imageable surface of the imaging member to a printable substrate at an ink transfer temperature. A process including combining water, an optional co-solvent, an optional colorant, a polyester, and a polymer additive, wherein the polymer additive is selected from a member of the group consisting of styrene-butadiene, acrylonitrile-butadiene, acrylonitrile-butadiene-styrene, and combinations thereof, to form an aqueous ink composition.

Claims

1. An aqueous ink composition comprising: water; an optional co-solvent; an optional colorant; a polyester; and a polymer additive, wherein the polymer additive is selected from a member of the group consisting of styrene-butadiene, acrylonitrile-butadiene, acrylonitrile-butadiene-styrene, and combinations thereof.

2. The ink composition of claim 1, wherein the polymer additive is provided in the form of a dispersion.

3. The ink composition of claim 1, wherein the polymer additive is selected from a member of the group consisting of carboxylated styrene-butadiene, carboxylated acrylonitrile-butadiene, carboxylated acrylonitrile-butadiene-styrene, noncarboxylated styrene-butadiene, noncarboxylated acrylonitrile-butadiene, noncarboxylated acrylonitrile-butadiene-styrene, and combinations thereof.

4. The ink composition of claim 1, wherein the polymer additive is an acrylonitrile-butadiene having a high acrylonitrile content of from about 50 percent or greater acrylonitrile.

5. The ink composition of claim 1, wherein the polymer additive is an acrylonitrile-butadiene-styrene having a high acrylonitrile content of from about 50 percent or greater acrylonitrile.

6. The ink composition of claim 1, wherein the polymer additive is an acrylonitrile-butadiene having a medium acrylonitrile content of about 32 percent acrylonitrile.

7. The ink composition of claim 1, wherein the polymer additive is an acrylonitrile-butadiene-styrene having a medium acrylonitrile content of about 32 percent acrylonitrile.

8. The ink composition of claim 1, wherein the polymer additive is an acrylonitrile-butadiene having a low acrylonitrile content of about 18 percent acrylonitrile.

9. The ink composition of claim 1, wherein the polymer additive is an acrylonitrile-butadiene-styrene having a low acrylonitrile content of about 18 percent acrylonitrile.

10. The ink composition of claim 1, wherein the polymer additive is present in the ink composition in an amount of from about 1 to about 10 percent by weight based upon the total weight of the ink composition.

11. The ink composition of claim 1, wherein the polyester is a sulfonated polyester.

12. The ink composition of claim 1, wherein the polyester is a sulfonated polyester having a degree of sulfonation of at least about 7.5 mol percent.

13. The ink composition of claim 1, wherein the polyester is a sodium sulfonated polyester.

14. The ink composition of claim 1, wherein the co-solvent is present and is selected from the group consisting of sulfolane, methyl ethyl ketone, isopropanol, 2-pyrrolidinone, polyethylene glycol, and mixtures thereof.

15. The ink composition of claim 1, wherein the colorant is present and comprises a pigment, a pigment dispersion, or a combination thereof.

16. The ink composition of claim 1, wherein the ink composition has the characteristic of providing substantially 100 percent transfer from a blanket to a substrate in an offset printing process.

17. A process of digital offset printing, the process comprising: applying an ink composition onto a re-imageable imaging member surface at an ink take up temperature, the re-imageable imaging member having dampening fluid disposed thereon; forming an ink image; transferring the ink image from the re-imageable surface of the imaging member to a printable substrate at an ink transfer temperature; wherein the ink composition comprises water, an optional co-solvent, an optional colorant, a polyester, and a polymer additive, wherein the polymer additive is selected from a member of the group consisting of styrene-butadiene, acrylonitrile-butadiene, acrylonitrile-butadiene-styrene, and combinations thereof.

18. The process of claim 17, wherein the polymer additive is selected from a member of the group consisting of carboxylated styrene-butadiene, carboxylated acrylonitrile-butadiene, carboxylated acrylonitrile-butadiene-styrene, noncarboxylated styrene-butadiene, noncarboxylated acrylonitrile-butadiene, noncarboxylated acrylonitrile-butadiene-styrene, and combinations thereof.

19. The process of claim 17, wherein applying the ink composition comprises applying the ink composition using an anilox delivery system.

20. A process comprising: combining water, an optional co-solvent, an optional colorant, a polyester, and a polymer additive, wherein the polymer additive is selected from a member of the group consisting of styrene-butadiene, acrylonitrile-butadiene, acrylonitrile-butadiene-styrene, and combinations thereof, to form an aqueous ink composition.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG. 1 illustrates a schematic representation of a related art ink-based variable image digital printing system with which the ink compositions according to this disclosure may be used.

[0032] FIG. 2 shows a schematic representation of a method for preparing sulfonated polyester latex materials.

[0033] FIG. 3 is a graph showing complex viscosity (y-axis, mPa-s) versus frequency (x-axis, rad/sec) for ink compositions in accordance with the present disclosure.

[0034] FIG. 4 is an image of three rolled sheets prepared with inks in accordance with the present embodiments.

[0035] FIG. 5 is an illustration of a print prepared in accordance with the present disclosure after water and scratch testing.

DETAILED DESCRIPTION

[0036] Waterborne digital offset printing ink compositions containing aqueous-compatible pigment, self-dispersing sulfo-polyester particles and acrylonitrile-butadiene-styrene (ABS) as an enabling additive to achieve desired properties for inking, release and image permanence are described. Digital offset printing curable inks must meet specific sub-system requirements that are unique to digital offset lithographic printing architecture. The most important requirements are wetting and release properties from the offset plate used for digital offset lithography printing processes and compatibility with non-aqueous fountain fluid options. Another requirement is adequate function within the ink delivery system (anilox roll). The aqueous ink compositions disclosed herein demonstrate good inking from the anilox delivery system, wetting to the blanket substrate, and blanket transfer to the print substrate (for example, paper or film). The use of a nitrile latex additive enables the formation of a highly robust film surpassing previous waterborne digital offset lithography ink image permanence.

[0037] The ink compositions can be used for any suitable or desired purpose. In embodiments, the ink compositions herein are particularly suitable for digital offset lithography printing, in embodiments, for printing labels, packaging, and in particular for food grade and medical grade printing. In embodiments, the ink herein is suitable for use as an undercoat in a printing process. The digital offset inks herein containing the particular combination of components, in embodiments, a combination of polyester, in embodiments, sulfonated polyester and polymer additive, in embodiments, a polymer additive provided in the form of a polymer dispersion, wherein the polymer additive is selected from a member of the group consisting of styrene-butadiene, acrylonitrile-butadiene, acrylonitrile-butadiene-styrene, and combinations thereof, provide improved transfer performance over prior digital offset ink compositions.

[0038] The ink compositions may include water-dissipatible sulfopolyester materials for the polymer matrix, with an ABS dispersion additive to increase internal cohesion. Without wishing to be bound by theory, inclusion of the present polymer additive, in embodiments, a member of the group consisting of styrene-butadiene, acrylonitrile-butadiene, acrylonitrile-butadiene-styrene, and combinations thereof, is believed to enable 100% ink transfer from the central imaging cylinder, and impart robustness to the final print. Formulations may include water dispersible pigment dispersions in order to achieve cyan, magenta, yellow, and black (CMYK) coloured inks, as well as covering specialty colours.

[0039] In embodiments, an aqueous ink composition herein comprises water; an optional co-solvent; an optional colorant; a polyester; and a polymer additive, wherein the polymer additive is selected from a member of the group consisting of styrene-butadiene, acrylonitrile-butadiene, acrylonitrile-butadiene-styrene, and combinations thereof.

[0040] As described in FIG. 1, it is highly advantageous to ensure inking uniformity and delivery of the ink from the ink loader system (or inker unit) and that the ink has relatively low viscosity within a temperature range of, in embodiments, from about 45 to about 80 C., such as from about 50 to about 70 C., such as from about 55 to about 65 C., such as about 60 C., at shear rates corresponding to the equivalent angular frequencies from about 50 to about 200 rad/s such as about 100 rad/s. It is also highly advantageous to ensure a high degree of ink transfer from the anilox roller to the blanket such that the ink has relatively high viscosity within a temperature range of, in embodiments, from about 18 to about 35 C., such as from about 18 to about 30 C., such as about 25 C., at shear rates corresponding to the equivalent angular frequencies from about 0.5 to about 2 rad/s such as about 1 rad/s.

[0041] In embodiments, the ink composition has a first viscosity of from about 3,000 to about 90,000 centipoise at an ink take up temperature of from about 45 C. to about 80 C.; and the ink composition has a second viscosity of from about 100,000 to about 2,000,000 centipoise at an ink transfer temperature of from about 18 C. to about 30 C.

[0042] In embodiments, the ink composition has a first viscosity of from about 3,000 to about 90,000 centipoise at an ink take up temperature of from about 45 C. to about 80 C. and a relatively higher shear rate of from about 50 rad/s to about 200 rad/s; and the ink composition has a second viscosity of from about 100,000 to about 2,000,000 centipoise at an ink transfer temperature of from about 18 C. to about 30 C. and a relatively lower angular frequency of from about 0.5 rad/s to about 2 rad/s.

[0043] In order to meet digital offset printing requirements, the ink desirably possesses many physical and chemical properties. The ink is desirably compatible with materials it is in contact with, including printing plate, fountain solution, and other cured or non-cured inks. It also desirably meets functional requirements of the sub-systems, including wetting and transfer properties. Transfer of the imaged inks is challenging, as the ink desirably possesses the combination of wetting and transfer traits, that is, the ink desirably at once wets the blanket material homogeneously, and transfers from the blanket to the substrate. Transfer of the image layer is desirably efficient, desirably at least as high as 90%, as the cleaning sub-station can only eliminate small amounts of residual ink. Any ink remaining on the blanket after cleaning can result in an unacceptable ghost image appearing in subsequent prints.

[0044] In embodiments, the ink composition herein has the characteristic of providing substantially 100 percent transfer from the re-imageable imaging member surface to the printable substrate.

[0045] In embodiments, the ink compositions herein include water-dissipatible sulfopolyester materials as a polymer matrix, with a polymer additive, in embodiments, with a polymer additive provided in the form of a polymer dispersion. Without wishing to be bound by theory, it is believed that the polymer additive, alone, or in combination with the polyester, increases internal cohesion and enables 100 percent ink transfer from the central imaging cylinder.

[0046] The ink compositions herein include a polymer additive, in embodiments, a polymer additive provided in the form of a polymer latex, a polymer dispersion, or a polymer emulsion, wherein the polymer additive is selected from a member of the group consisting of styrene-butadiene, acrylonitrile-butadiene, acrylonitrile-butadiene-styrene, and combinations thereof.

[0047] As used herein, the term dispersion means a two phase system where one phase consists of finely divided particles (often in the colloidal size range) distributed throughout a bulk substance, the particles being the dispersed or internal phase and the bulk substance being the continuous or external phase. The bulk system is often an aqueous system.

[0048] In embodiments, the polymer additive is provided in the form of a dispersion. The polymer additive dispersions may include any suitable or desired percent solids in water. In embodiments, the polymer additive dispersions comprise from about 30 to about 60 percent solids, or from about 33 to about 54 percent solids, or from about 43 to about 49 percent solids.

[0049] The polymer additive may be carboxylated or noncarboxylated. In embodiments, the polymer additive is selected from a member of the group consisting of carboxylated styrene-butadiene, carboxylated acrylonitrile-butadiene, carboxylated acrylonitrile-butadiene-styrene, noncarboxylated styrene-butadiene, noncarboxylated acrylonitrile-butadiene, noncarboxylated acrylonitrile-butadiene-styrene, and combinations thereof.

[0050] In embodiments, the polymer additive comprises acrylonitrile-butadiene. The acrylonitrile-butadiene may be selected from those having a high, medium, or low nitrile content.

[0051] In embodiments, the polymer additive is an acrylonitrile-butadiene having a high acrylonitrile content, in embodiments, of from about 50 percent acrylonitrile or greater. In other embodiments, the polymer additive is an acrylonitrile-butadiene having a medium acrylonitrile content, in embodiments, of about 32 percent acrylonitrile. In other embodiments, the polymer additive is an acrylonitrile-butadiene having a low acrylonitrile content, in embodiments, of about 18 percent acrylonitrile or less.

[0052] In embodiments, the polymer additive comprises acrylonitrile-butadiene-styrene. The acrylonitrile-butadiene-styrene may be selected from those having a high, medium, or low nitrile content. In embodiments, the polymer additive is an acrylonitrile-butadiene-styrene having a high acrylonitrile content, in embodiments, of from about 50 percent acrylonitrile or greater. In other embodiments, the polymer additive is an acrylonitrile-butadiene-styrene having a medium acrylonitrile content, in embodiments of about 32 percent acrylonitrile. In other embodiments, the polymer additive is an acrylonitrile-butadiene-styrene having a low acrylonitrile content, in embodiment, of from about 18 percent acrylonitrile or less.

[0053] In embodiments the polymer additive comprises acrylonitrile-butadiene-styrene wherein the ratio of component acrylonitrile, butadiene and styrene may be about 15 to about 35 percent, about 5 to about 30 percent, and about 40 to about 60 percent, respectively.

[0054] In embodiments, any suitable or desired polymer additive as described herein can be selected for the present ink compositions. In certain embodiments, the polymer additive comprises a waterborne emulsion of acrylonitrile-butadiene, acrylonitrile-butadiene-styrene, or styrene-butadiene. Examples of commercially available butadiene acrylonitrile, acrylonitrile-butadiene-styrene, and styrene-butadiene dispersions include Nychem 1578x1 available from Emerald Performance Materials. Nychem 1578x1 is a carboxylated butadiene acrylonitrile polymer latex. Other suitable materials include those having high and medium acrylonitrile content such as Nychem 1561X87; Nychem 1561X98; Nychem 1571X12; Nychem 1571X8; Nychem 1552; Nychem 152X103; Nychem 1562X117; Nychem 1562X28; Nychem 1570X79; Nychem 1572; Nychem 1572X32; Nychem 1572X64; Nychem XPE 140, as well as those with acrylonitrile-butadiene-styrene (ABS) content, such as Nychem 1562X170; Nychem 1570X75; Nychem 1577; Nychem 1578X1; and Nychem XPE 130. Further, suitable specialty butadiene products include Nychem 1561; Nychem 1562; Nychem 1562X160; Nychem 1563; Nychem 1581; Nychem 1800X73; Nychem 1871X3; Nychem 2570X59; Nychem 552; Nychem N2000 and Nychem N4000.

[0055] The polymer additive can be present in the ink composition in any suitable or desired amount. In embodiments, the polymer additive is present in an amount of from about 1 to about 35, or from about 10 to about 30, or from about 15 to about 25 percent by weight, based upon the total weight of the ink composition. In embodiments, the polymer additive is present in the ink composition in an amount of from about 1 percent by weight to about 10 percent by weight, based upon a total weight of the ink composition.

[0056] The ink composition herein includes a polyester. In embodiments, the polyester is provided in the form of a polyester latex.

[0057] In embodiments, the ink composition includes a sulfonated polyester. In embodiments, the sulfonated polyester has a high degree of sulfonation, in embodiments, the sulfonated polyester has a degree of sulfonation of at least about 3.5 mol percent, at least about 4 mol percent, at least about 7 mol percent, or at least about 7.5 mol percent.

[0058] In embodiments, the sulfonated polyester has a degree of sulfonation of from at least about 3.5 mol percent to about 3.75 mol percent, or from at least about 4 mol percent to about 5.5 mol percent, or from at least about 7.0 mol percent to about 7.5 mol percent.

[0059] As used herein, mol percent refers, for example, to the percentage of moles of sulfonated monomer present in the final resin and can be calculated, for example, as (moles DMSIP (Dimethyl-5-Sulfoisophthalate Sodium Salt) charged/(total moles charged less excess moles glycol)100 percent).

[0060] The sulfonated polyester is a self-dissipatible polymer, meaning that it can be dispersed in water without the need for additional surfactants.

[0061] The sulfonated polyester can be simultaneously synthesized during the self-assembly or dispersing of polymer in water as indicated in FIG. 2. Referring to FIG. 2, the sulfonated polyester is dispersed in water, for example at a temperature of about 90 C., providing a hydrophobic resin core and hydrophilic surface sulfonate groups.

[0062] The sulfonated polyester resins disclosed herein have been selected to have a hydrophobic backbone while presenting hydrophilic sulfonate groups attached along the chain. Without being bound by theory, when placed in water and heated, the hydrophobic portions may interact with each other to form a hydrophobic core with the hydrophilic sulfonate groups facing the surrounding water resulting in the sulfonated polyester self-assembling into a higher order, spherical nanoparticle without the requirement of additional reagents, such as surfactants or dispersants, which are typically required to stabilize colloidal dispersions. Thus, there is a higher order involving the amphiphilic polyester, in which the hydrophobic backbone, which is insoluble in water, and the water-soluble hydrophilic sulfonate groups, operate as macrosurfactants. This results in self-association, self-assembly, self-dispersible nanoparticles in aqueous medium to yield micelle-like aggregates.

[0063] In embodiments, the sulfonated polyester matrix is a branched polymer. In embodiments, the sulfonated polyester matrix is a linear polymer. The selection of branched or linear polymer may depend on, inter alia, the downstream application of the composite product. Linear polymers can be used to create strands of fibers or form a strong mesh-like structure. Branched polymers may be useful to confer thermoplastic properties on the resultant composite material.

[0064] Both linear amorphous and branched amorphous sulfonated polyester resins are alkali sulfonated polyester resins. The alkali metal in the respective sulfonated polyester resins may independently be lithium, sodium, or potassium. In a specific embodiment, the alkali metal in the respective sulfonated polyester resin is sodium.

[0065] In embodiments, the sulfonated polyester matrix is selected from the group consisting of poly(1,2-propylene-5-sulfoisophthalate), poly(neopentylene-5-sulfoisophthalate), poly(diethylene-5-sulfoisophthalate), copoly-(1,2-propylene-5-sulfoisophthalate)-copoly-(1,2-propylene-terphthalate), copoly-(1,2-propylenediethylene-5-sulfoisophthalate)-copoly-(1,2-propylene-diethylene-terephthalatephthalate), copoly(ethylene-neopentylene-5-sulfoisophthalate)-copoly-(ethylene-neopentylene-terephthalatephthalate), and copoly(propoxylated bisphenol A)-copoly-(propoxylated bisphenol A-5-sulfoisophthalate). Thus, in embodiments, the sulfonated polyester matrix is lithium, potassium, or sodium salt, in specific embodiments, a sodium salt, of a polymer selected from the group consisting of poly(1,2-propylene-5-sulfoisophthalate), poly(neopentylene-5-sulfoisophthalate), poly(diethylene-5-sulfoisophthalate), copoly-(1,2-propylene-5-sulfoisophthalate)-copoly-(1,2-propylene-terphthalate), copoly-(1,2-propylenediethylene-5-sulfoisophthalate)-copoly-(1,2-propylene-diethylene-terephthalatephthalate), copoly(ethylene-neopentylene-5-sulfoisophthalate)-copoly-(ethylene-neopentylene-terephthalatephthalate), and copoly(propoxylated bisphenol A)-copoly-(propoxylated bisphenol A-5-sulfoisophthalate).

[0066] In general, the sulfonated polyesters may have the following general structure, or random copolymers thereof in which the n and p segments are separated.

##STR00001##

[0067] wherein R is an alkylene of, for example, from 2 to about 25 carbon atoms such as ethylene, propylene, butylene, oxyalkylene diethyleneoxide, and the like; R is an arylene of, for example, from about 6 to about 36 carbon atoms, such as a benzylene, bisphenylene, bis(alkyloxy) bisphenolene, and the like; X is a halogen, in embodiments, be lithium, sodium, or potassium, in embodiments, sodium; and p and n represent the number of randomly repeating segments, such as for example from about 10 to about 100,000.

[0068] In embodiments, the sulfonated polyester is a sodium sulfonated polyester having the structure

##STR00002##

[0069] wherein R is an alkylene of, for example, from 2 to about 25 carbon atoms such as ethylene, propylene, butylene, oxyalkylene diethyleneoxide, and the like; R.sub.1 is an alkylene of, for example, from 2 to about 25 carbon atoms such as ethylene, propylene, butylene, oxyalkylene diethyleneoxide, and the like; or an arylene of, for example, from about 6 to about 36 carbon atoms, such as a benzylene, bisphenylene, bis(alkyloxy) bisphenolene, and the like; or wherein, in embodiments, R and R.sub.1 are each an alkyene of, for example, from about 2 to about 10 carbon atoms; and x, y and z represent the number of randomly repeating segments, such as for example from about 10 to about 100,000, wherein, in embodiments, y is from about 3.5 mol percent, or greater than about 3.5 mol percent, or from at least about 3.5 mol percent to about 20 mol percent, or from at least about 3.5 mol percent to about 15 mol percent, or from at least about 3.5 mol percent to about 10 mol percent of the resin; or

[0070] wherein R is aliphatic having from about 2 to about 10 carbon atoms and R.sub.1 is aliphatic having from about 2 to about 10 carbon atoms; where y is from about 3 to about 7.5 percent. Higher than 7.5 percent is usually water soluble.

[0071] Examples further include those disclosed in U.S. Pat. No. 7,312,011 which is hereby incorporated by reference herein in its entirety. Specific examples of amorphous alkali sulfonated polyester based resins include, but are not limited to, copoly(ethylene-terephthalate)-copoly-(ethylene-5-sulfo-isophthalate), copoly(propylene-terephthalate)-copoly(propylene-5-sulfo-isophthalate), copoly(diethylene-terephthalate)-copoly(diethylene-5-sulfo-isophthalate), copoly(propylene-diethylene-terephthalate)-copoly(propylene-diethylene-5-sulfo-isophthalate), copoly(propylene-butylene-terephthalate)-copoly(propylene-butylene-5-sulfo-isophthalate), copoly(propoxylated bisphenol-A-fumarate)-copoly(propoxylated bisphenol A-5-sulfo-isophthalate), copoly(ethoxylated bisphenol-A-fumarate)-copoly(ethoxylated bisphenol-A-5-sulfo-isophthalate), and copoly(ethoxylated bisphenol-A-maleate)-copoly(ethoxylated bisphenol-A-5-sulfo-isophthalate), and wherein the alkali metal is, for example, a sodium, lithium or potassium ion. Examples of crystalline alkali sulfonated polyester based resins include, but are not limited to, alkali copoly(5-sulfoisophthaloyl)-co-poly(ethylene-adipate), alkali copoly(5-sulfoisophthaloyl)-copoly(propylene-adipate), alkali copoly(5-sulfoisophthaloyl)-copoly(butylene-adipate), alkali copoly(5-sulfo-isophthaloyl)-copoly(pentylene-adipate), and alkali copoly(5-sulfo-iosphthaloyl)-copoly(octylene-adipate), alkali copoly(5-sulfo-isophthaloyl)-copoly(ethylene-adipate), alkali copoly(5-sulfo-isophthaloyl)-copoly (propylene-adipate), alkali copoly(5-sulfo-isophthaloyl)-co-poly(butylene-adipate), alkali copoly(5-sulfo-isophthaloyl)-copoly(pentylene-adipate), alkali copoly(5-sulfo-isophthaloyl)-copoly(hexylene-adipate), alkali copoly(5-sulfo-isophthaloyl)-copoly(octylene-adipate), alkali copoly(5-sulfoisophthaloyl)-copoly(ethylene-succinate), alkali copoly(5-sulfoisophthaloyl-copoly(butylene-succinate), alkali copoly(5-sulfoisophthaloyl)-copoly(hexylene-succinate), alkali copoly(5-sulfoisophthaloyl)-copoly(octylene-succinate), alkali copoly(5-sulfo-isophthaloyl)-copoly(ethylene-sebacate), alkali copoly(5-sulfo-isophthaloyl)-copoly(propylene-sebacate), alkali copoly(5-sulfo-isophthaloyl)-copoly(butylene-sebacate), alkali copoly(5-sulfo-isophthaloyl)-copoly(pentylene-sebacate), alkali copoly(5-sulfo-isophthaloyl)-copoly(hexylene-sebacate), alkali copoly(5-sulfo-isophthaloyl)-copoly(octylene-sebacate), alkali copoly(5-sulfo-isophthaloyl)-copoly(ethylene-adipate), alkali copoly(5-sulfo-isophthaloyl)-copoly(propylene-adipate), alkali copoly(5-sulfo-iosphthaloyl)-copoly(butylene-adipate), alkali copoly(5-sulfo-isophthaloyl)-copoly(pentylene-adipate), alkali copoly(5-sulfo-isophthaloyl)copoly(hexylene-adipate), poly(octylene-adipate), and wherein the alkali is a metal such as sodium, lithium or potassium. In specific embodiments, the alkali metal is sodium.

[0072] The linear amorphous polyester resins are generally prepared by the polycondensation of an organic diol and a diacid or diester, at least one of which is sulfonated or a sulfonated difunctional monomer being included in the reaction, and a polycondensation catalyst. For the branched amorphous sulfonated polyester resin, the same materials may be used, with the further inclusion of a branching agent such as a multivalent polyacid or polyol.

[0073] Examples of diacid or diesters selected for the preparation of amorphous polyesters include dicarboxylic acids or diesters selected from the group consisting of terephthalic acid, phthalic acid, isophthalic acid, sulfonated isophthalic acid, fumaric acid, maleic acid, itaconic acid, succinic acid, succinic anhydride, dodecylsuccinic acid, dodecylsuccinic anhydride, glutaric acid, glutaric anhydride, adipic acid, pimelic acid, suberic acid, azelic acid, dodecanediacid, dimethyl terephthalate, diethyl terephthalate, dimethylisophthalate, diethylisophthalate, dimethylphthalate, phthalic anhydride, diethylphthalate, dimethylsuccinate, dimethylfumarate, dimethylmaleate, dimethylglutarate, dimethyladipate, dimethyl dodecylsuccinate, and mixtures thereof. The organic diacid or diester are selected, for example, from about 45 to about 52 mole percent of the resin. Examples of diols utilized in generating the amorphous polyester include trimethylolpropane, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, pentanediol, hexanediol, 2,2-dimethylpropanediol, 2,2,3-trimethylhexanediol, heptanediol, dodecanediol, bis(hydroxyethyl)-bisphenol A, bis(2-hydroxypropyl)-bisphenol A, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, xylenedimethanol, cyclohexanediol, diethylene glycol, bis(2-hydroxyethyl) oxide, dipropylene glycol, dibutylene, and mixtures thereof. The amount of organic diol selected can vary, and more specifically, is, for example, from about 45 to about 52 mole percent of the resin. In embodiments, the sulfonated polyester matrix comprises a polyol monomer unit selected from the group consisting of trimethylolpropane, 1,2-propanediol, diethylene glycol, and combinations thereof. In embodiments, the sulfonated polyester matrix comprises a polyol monomer unit selected from the group consisting of trimethylolpropane, 1,2-propanediol, diethylene glycol, and combinations thereof. In embodiments, the sulfonated polyester comprises a polyol monomer unit selected from the group consisting of trimethylolpropane, 1,2-propanediol, diethylene glycol, and combinations thereof; and the sulfonated polyester comprises a diacid monomer unit selected from the group consisting of terephthalic acid, sulfonated isophthalic acid, and combinations thereof.

[0074] Alkali sulfonated difunctional monomer examples, wherein the alkali is lithium, sodium, or potassium, and in particular embodiments wherein the alkali is sodium, include dimethyl-5-sulfo-isophthalate, dialkyl-5-sulfo-isophthalate-4-sulfo-1,8-naphthalic anhydride, 4-sulfo-phthalic acid, 4-sulfophenyl-3,5-dicarbomethoxybenzene, 6-sulfo-2-naphthyl-3,5-dicarbomethoxybenzene, sulfo-terephthalic acid, dimethyl-sulfo-terephthalate, dialkyl-sulfo-terephthalate, sulfo-ethanediol, 2-sulfo-propanediol, 2-sulfo-butanediol, 3-sulfo-pentanediol, 2-sulfo-hexanediol, 3-sulfo-2-methylpentanediol, N,N-bis(2-hydroxyethyl)-2-aminoethane sulfonate, 2-sulfo-3,3-dimethylpentanediol, sulfo-p-hydroxybenzoic acid, mixtures thereof, and the like. Effective difunctional monomer amounts of, for example, from about 0.1 to about 2 weight percent of the resin can be selected.

[0075] Branching agents for use in forming the branched amorphous sulfonated polyester include, for example, a multivalent polyacid such as 1,2,4-benzene-tricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylene-carboxylpropane, tetra(methylene-carboxyl)methane, and 1,2,7,8-octanetetracarboxylic acid, acid anhydrides thereof, and lower alkyl esters thereof, 1 to about 6 carbon atoms; a multivalent polyol such as sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitane, pentaerythritol, dipentaerythritol, tripentaerythritol, sucrose, 1,2,4-butanetriol, 1,2,5-pentatriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene, mixtures thereof, and the like. The branching agent amount selected is, for example, from about 0.1 to about 5 mole percent of the resin.

[0076] Polycondensation catalyst examples for amorphous polyesters include tetraalkyl titanates, dialkyltin oxide such as dibutyltin oxide, tetraalkyltin such as dibutyltin dilaurate, dialkyltin oxide hydroxide such as butyltin oxide hydroxide, aluminum alkoxides, alkyl zinc, dialkyl zinc, zinc oxide, stannous oxide, or mixtures thereof; and which catalysts are selected in amounts of, for example, from about 0.01 mole percent to about 5 mole percent based on the starting diacid or diester used to generate the polyester resin.

[0077] In embodiments, after polymerization, the resulting sulfonated polyesters may comprise an aryl unit, a sulfonated unit, and a aliphatic unit having the following formulae:

##STR00003##

[0078] wherein each R.sub.1 and each R.sub.2 may be independently an alkylene of, for example, from 2 to about 25 carbon atoms such as ethylene, propylene, butylene, oxyalkylene diethyleneoxide, and the like; each R.sub.3 may be independently an alkyl group of, for example, from 1 to 15 carbon atoms, branched or unbranched, such as, methyl, ethyl, propyl, isopropyl, butyl, and the like; each R may be independently an arylene of, for example, from about 6 to about 36 carbon atoms, such as a benzylene, bisphenylene, bis(alkyloxy) bisphenolene, and the like; each X.sup.+ may be independently Na.sup.+, Li.sup.+, K.sup.+, and the like; and each n, each p and each q represent the number of randomly repeating segments, each of which may be independently from about 10 to about 100,000. In embodiments, n is from about 40 to about 50 mol percent, from about 42.5 to about 46.5 mol percent, or from about 43 to about 45 mol percent. In embodiments, p is from about 7.5 to about 15 mol %, from about 8 to about 12 mol percent. In embodiments, q is from about 0.1 to about 4 mol percent, 0.1 to about 2.5 mol percent, or from about 0.2 to about 1.5; p represents the amount of sulfonation in the sulfonated polyester; q represents the amount of crosslinker in the sulfonated polyester; and n is 100(p+q).

[0079] In embodiments, the sulfonated polyesters suitable for use in the present disclosure may have a glass transition (Tg) temperature of from about 45 C. to about 95 C., or from about 52 C. to about 70 C., as measured by the Differential Scanning Calorimeter. In embodiments, the sulfonated polyesters may have a number average molecular weight of from about 2,000 grams per mole to about 150,000 grams per mole, from about 3,000 grams per mole to about 50,000 grams per mole, or from about 6,000 grams per mole to about 15,000 grams per mole, as measured by the Gel Permeation Chromatograph. In embodiments, the sulfonated polyesters may have a weight average molecular weight of from about 3,000 grams per mole to about 300,000 grams per mole, from about 8,000 grams per mole to about 90,000 grams per mole, or from about 10,000 grams per mole to about 60,000 grams per mole, as measured by the Gel Permeation Chromatograph. In embodiments, the sulfonated polyesters may have a polydispersity of from about 1.6 to about 100, from about 2.0 to about 50, or from about 5.0 to about 30, as calculated by the ratio of the weight average to number average molecular weight.

[0080] As used herein, references to particle size will generally refer to D.sub.50 mass-median-diameter (MMD) or the log-normal distribution mass median diameter. The MMD is considered to be the average particle diameter by mass.

[0081] In embodiments, the polyester has a particle size in a range of from about 5 nanometers (nm) to about 500 nm or from about 10 to about 200 nm, or from about 20 to about 100 nm. A particle size of less than 100 nm may be useful for reinforcement of polymer matrices without disturbing transparency and other properties of coatings.

[0082] In embodiments, the polyester has a particle size of from about 5 nanometers to about 55 nanometers. In further embodiments, the polyester has a particle size of from about 10 nanometers to about 15 nanometers.

[0083] In embodiments, there are provided methods comprising heating a sulfonated polyester resin in water, thereby forming an emulsion of composite particles comprising a sulfonated polyester.

[0084] In embodiments, heating is conducted at a temperature of from about 65 C. to about 90 C.

[0085] In certain embodiments, a method herein comprises heating a sulfonated polyester resin in water, in embodiments a sulfonated polyester resin, wherein the sodium sulfonated polyester has a degree of sulfonation of at least about 3.5 mol percent, or at least about 7.5 mol percent; and forming an emulsion of particles comprising the sulfonated polyester. In embodiments, the method further comprises combining the polyester particles with water, an optional colorant, an optional co-solvent, and a polyurethane, in embodiments, a polyurethane dispersion, to form an aqueous ink composition.

[0086] The sulfonated polyester can be present in the ink composition in any suitable or desired amount. In embodiments, the sulfonated polyester is present in the ink composition in an amount of from about 20 to about 60 percent by weight based upon the total weight of the ink composition, or from about 30 to about 50 percent by weight based upon the total weight of the ink composition, or from about 35 to about 45 percent by weight based upon the total weight of the ink composition.

[0087] The ink can be used in any suitable or desired printing application. The ink herein is particularly useful for indirect printing applications wherein the ink wets the intermediate receiving member enabling formation of a transient image on the intermediate receiving followed by release from the intermediate receiving member in the transfer printing step. In embodiments, the ink undergoes partial or complete drying while on the intermediate transfer member.

[0088] Ink compositions herein specifically suitable for indirect printing systems, are also compatible with different printing subsystems including jetting and transfer subsystems, and enable high quality printing at high speed. In embodiments, ink compositions herein enable and perform well in both wetting and transfer subsystems, displaying both acceptable wettability characteristics in combination with acceptable release and transfer characteristics.

[0089] The ink compositions herein can consist solely of water, or can comprise a mixture of water and a water soluble or water miscible component, referred to as a co-solvent, humectant, or the like (hereinafter co-solvent) such as alcohols and alcohol derivatives, including aliphatic alcohols, aromatic alcohols, dials, glycol ethers, polyglycol ethers, long chain alcohols, primary aliphatic alcohols, secondary aliphatic alcohols, 1,2-alcohols, 1,3-alcohols, 1,5-alcohols, ethylene glycol alkyl ethers, propylene glycol alkyl ethers, methoxylated glycerol, ethoxylated glycerol, higher homologues of polyethylene glycol alkyl ethers, and the like, with specific examples including ethylene glycol, propylene glycol, diethylene glycols, glycerine, dipropylene glycols, polyethylene glycols, polypropylene glycols, trimethylolpropane, 1,5-pentanediol, 2-methyl-1,3,-propanediol, 2-ethyl-2-hydroxymethyl-1,3-propanediol, 3-methoxybutanol, 3-methyl-1,5-pentanediol, 1,3-propanediol, 1,4-butanediol, 2,4-heptanediol, and the like; also suitable are amides, ethers, urea, substituted ureas such as thiourea, ethylene urea, alkylurea, alkylthiourea, dialkylurea, and dialkylthiourea, carboxylic acids and their salts, such as 2-methylpentanoic acid, 2-ethyl-3-propylacrylic acid, 2-ethyl-hexanoic acid, 3-ethoxyproponic, acid, and the like, esters, organosulfides, organosulfoxides, sulfones (such as sulfolane), carbitol, butyl carbitol, cellusolve, ethers, tripropylene glycol monomethyl ether, ether derivatives, hydroxyethers, amino alcohols, ketones, N-methylpyrrolidinone, 2-pyrrolidinone, cyclohexylpyrrolidone, amides, sulfoxides, lactones, polyelectrolytes, methyl sulfonylethanol, imidazole, 1,3-dimethyl-2-imidazolidinone, betaine, sugars, such as 1-deoxy-D-galactitol, mannitol, inositol, and the like, substituted and unsubstituted formamides, substituted and unsubstituted acetamides, and other water soluble or water miscible materials, as well as mixtures thereof. In embodiments, the co-solvent is selected from the group consisting of ethylene glycol, N-methylpyrrolidone, methoxylated glycerol, ethoxylated glycerol, and mixtures thereof.

[0090] When mixtures of water and water soluble or miscible organic solvent liquids are selected as the liquid vehicle, the water to organic co-solvent ratio ranges can be any suitable or desired ratio, in embodiments from about 100:0 to about 30:70, or from about 97:3 to about 40:60, or from about 95:5 to about 60:40. The non-water component of the liquid vehicle generally serves as a humectant or co-solvent which has a boiling point higher than that of water (100 C.). The co-solvent selected is one that will mix with water without phase separation; thus, a co-solvent having a polarity that is compatible with water is selected. The organic component of the ink vehicle can also serve to modify ink surface tension, modify ink viscosity, dissolve or disperse the colorant, and/or affect the drying characteristics of the ink. In embodiments, the ink is more attracted to paper substrates than plastic media as in solvent-based inks.

[0091] The water soluble or water miscible organics which are used in the ink formulation can help with surface tension, drying, leveling, etc. In embodiments, water makes up over 50% of the formulation, in embodiments water comprises from about 60 to about 70% of the ink composition. Thus, the ink compositions herein are mainly aqueous.

[0092] In certain embodiments, the co-solvent is selected from the group consisting of sulfolane, methyl ethyl ketone, isopropanol, 2-pyrrolidinone, polyethylene glycol, and mixtures thereof.

[0093] The total amount of liquid vehicle can be provided in any suitable or desired amount. In embodiments, the liquid vehicle is present in the ink composition in an amount of from about 75 to about 97 percent, or from about 80 to about 95 percent, or from about 85 to about 95 percent, by weight, based on the total weight of the ink composition.

[0094] The ink composition herein may also contain a colorant. Any suitable or desired colorant can be used in embodiments herein, including pigments, dyes, dye dispersions, pigments dispersions, and mixtures and combinations thereof.

[0095] The colorant may be provided in the form of a colorant dispersion. In embodiments, the colorant dispersion has an average particle size of from about 20 to about 500 nanometers (nm), or from about 20 to about 400 nm, or from about 30 to about 300 nm. In embodiments, the colorant is selected from the group consisting of dyes, pigments, and combinations thereof, and optionally, the colorant is a dispersion comprising a colorant, an optional surfactant, and an optional dispersant. In embodiments, the colorant is present and comprises a pigment, a pigment dispersion, or a combination thereof.

[0096] As noted, any suitable or desired colorant can be selected in embodiments herein. The colorant can be a dye, a pigment, or a mixture thereof. Examples of suitable dyes include anionic dyes, cationic dyes, nonionic dyes, zwitterionic dyes, and the like. Specific examples of suitable dyes include Food dyes such as Food Black No. 1, Food Black No. 2, Food Red No. 40, Food Blue No. 1, Food Yellow No. 7, and the like, FD & C dyes, Acid Black dyes (No. 1, 7, 9, 24, 26, 48, 52, 58, 60, 61, 63, 92, 107, 109, 118, 119, 131, 140, 155, 156, 172, 194, and the like), Acid Red dyes (No. 1, 8, 32, 35, 37, 52, 57, 92, 115, 119, 154, 249, 254, 256, and the like), Acid Blue dyes (No. 1, 7, 9, 25, 40, 45, 62, 78, 80, 92, 102, 104, 113, 117, 127, 158, 175, 183, 193, 209, and the like), Acid Yellow dyes (No. 3, 7, 17, 19, 23, 25, 29, 38, 42, 49, 59, 61, 72, 73, 114, 128, 151, and the like), Direct Black dyes (No. 4, 14, 17, 22, 27, 38, 51, 112, 117, 154, 168, and the like), Direct Blue dyes (No. 1, 6, 8, 14, 15, 25, 71, 76, 78, 80, 86, 90, 106, 108, 123, 163, 165, 199, 226, and the like), Direct Red dyes (No. 1, 2, 16, 23, 24, 28, 39, 62, 72, 236, and the like), Direct Yellow dyes (No. 4, 11, 12, 27, 28, 33, 34, 39, 50, 58, 86, 100, 106, 107, 118, 127, 132, 142, 157, and the like), Reactive Dyes, such as Reactive Red Dyes (No. 4, 31, 56, 180, and the like), Reactive Black dyes (No. 31 and the like), Reactive Yellow dyes (No. 37 and the like); anthraquinone dyes, monoazo dyes, disazo dyes, phthalocyanine derivatives, including various phthalocyanine sulfonate salts, aza(18)annulenes, formazan copper complexes, triphenodioxazines, and the like; as well as mixtures thereof.

[0097] Examples of suitable pigments include black pigments, white pigments, cyan pigments, magenta pigments, yellow pigments, and the like. Further, pigments can be organic or inorganic particles. Suitable inorganic pigments include carbon black. However, other inorganic pigments may be suitable such as titanium oxide, cobalt blue (CoOAl.sub.2O.sub.3), chrome yellow (PbCrO.sub.4), and iron oxide. Suitable organic pigments include, for example, azo pigments including diazo pigments and monoazo pigments, polycyclic pigments (e.g., phthalocyanine pigments such as phthalocyanine blues and phthalocyanine greens), perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, pyranthrone pigments, and quinophthalone pigments), insoluble dye chelates (e.g., basic dye type chelates and acidic dye type chelate), nitro pigments, nitroso pigments, anthanthrone pigments such as PR168, and the like. Representative examples of phthalocyanine blues and greens include copper phthalocyanine blue, copper phthalocyanine green, and derivatives thereof (Pigment Blue 15, Pigment Green 7, and Pigment Green 36). Representative examples of quinacridones include Pigment Orange 48, Pigment Orange 49, Pigment Red 122, Pigment Red 192, Pigment Red 202, Pigment Red 206, Pigment Red 207, Pigment Red 209, Pigment Violet 19, and Pigment Violet 42. Representative examples of anthraquinones include Pigment Red 43, Pigment Red 194, Pigment Red 177, Pigment Red 216 and Pigment Red 226. Representative examples of perylenes include Pigment Red 123, Pigment Red 149, Pigment Red 179, Pigment Red 190, Pigment Red 189 and Pigment Red 224. Representative examples of thioindigoids include Pigment Red 86, Pigment Red 87, Pigment Red 88, Pigment Red 181, Pigment Red 198, Pigment Violet 36, and Pigment Violet 38. Representative examples of heterocyclic yellows include Pigment Yellow 1, Pigment Yellow 3, Pigment Yellow 12, Pigment Yellow 13, Pigment Yellow 14, Pigment Yellow 17, Pigment Yellow 65, Pigment Yellow 73, Pigment Yellow 74, Pigment Yellow 90, Pigment Yellow 110, Pigment Yellow 117, Pigment Yellow 120, Pigment Yellow 128, Pigment Yellow 138, Pigment Yellow 150, Pigment Yellow 151, Pigment Yellow 155, and Pigment Yellow 213. Such pigments are commercially available in either powder or press cake form from a number of sources including, BASF Corporation, Engelhard Corporation, and Sun Chemical Corporation. Examples of black pigments that may be used include carbon pigments. The carbon pigment can be almost any commercially available carbon pigment that provides acceptable optical density and print characteristics. Carbon pigments suitable for use in the present system and method include, without limitation, carbon black, graphite, vitreous carbon, charcoal, and combinations thereof. Such carbon pigments can be manufactured by a variety of known methods, such as a channel method, a contact method, a furnace method, an acetylene method, or a thermal method, and are commercially available from such vendors as Cabot Corporation, Columbian Chemicals Company, Evonik, and E.I. DuPont de Nemours and Company. Suitable carbon black pigments include, without limitation, Cabot pigments such as MONARCH 1400, MONARCH 1300, MONARCH 1100, MONARCH 1000, MONARCH 900, MONARCH 880, MONARCH 800, MONARCH 700, CAB-O-JET 200, CAB-O-JET 300, REGAL, BLACK PEARLS, ELFTEX, MOGUL, and VULCAN pigments; Columbian pigments such as RAVEN 5000, and RAVEN 3500; Evonik pigments such as Color Black FW 200, FW 2, FW 2V, FW 1, FW18, FW S160, FW S170, Special Black 6, Special Black 5, Special Black 4A, Special Black 4, PRINTEX U, PRINTEX 140U, PRINTEX V, and PRINTEX 140V. The above list of pigments includes unmodified pigment particulates, small molecule attached pigment particulates, and polymer-dispersed pigment particulates. Other pigments can also be selected, as well as mixtures thereof. The pigment particle size is desired to be as small as possible to enable a stable colloidal suspension of the particles in the liquid vehicle and to prevent clogging of the ink channels when the ink is used in a thermal ink jet printer or a piezoelectric ink jet printer.

[0098] The colorant can be present in the ink composition in any desired or effective amount, in embodiments, the colorant can be present in an amount of from about 0.05 to about 15 percent, or from about 0.1 to about 10 percent, or from about 1 to about 5 percent by weight, based on the total weight of the ink composition.

[0099] In embodiments, the ink composition herein further enables use of a high colorant concentration, in embodiments a colorant or pigment concentration of greater than 50 percent, in embodiments, greater than 60 percent, by weight based on the total weight of the ink composition, while maintaining desired characteristics of desired viscosity at room temperature and desired viscosity at heated temperature for ink transfer.

[0100] The inks disclosed may also contain a surfactant. Examples of suitable surfactants include ionic surfactants, anionic surfactants, cationic surfactants, nonionic surfactants, zwitterionic surfactants, and the like, as well as mixtures thereof. Examples of suitable surfactants include alkyl polyethylene oxides, alkyl phenyl polyethylene oxides, polyethylene oxide block copolymers, acetylenic polyethylene oxides, polyethylene oxide (di)esters, polyethylene oxide amines, protonated polyethylene oxide amines, protonated polyethylene oxide amides, dimethicone copolyols, substituted amine oxides, and the like, with specific examples including primary, secondary, and tertiary amine salt compounds such as hydrochloric acid salts, acetic acid salts of laurylamine, coconut amine, stearylamine, rosin amine; quaternary ammonium salt type compounds such as lauryltrimethylammonium chloride, cetyltrimethylammonium chloride, benzyltributylammonium chloride, benzalkonium chloride, etc.; pyridinium salty type compounds such as cetylpyridinium chloride, cetylpyridinium bromide, etc.; nonionic surfactant such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters, acetylene alcohols, acetylene glycols; and other surfactants such as 2-heptadecenyl-hydroxyethylimidazoline, dihydroxyethylstearylamine, stearyldimethylbetaine, and lauryldihydroxyethylbetaine; fluorosurfactants; and the like, as well as mixtures thereof. Additional examples of nonionic surfactants include polyacrylic acid, methalose, methyl cellulose, ethyl cellulose, propyl cellulose, hydroxy ethyl cellulose, carboxy methyl cellulose, polyoxyethylene cetyl ether, polyoxyethylene lauryl ether, polyoxyethylene octyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene oleyl ether, polyoxyethylene sorbitan monolaurate, polyoxyethylene stearyl ether, polyoxyethylene nonylphenyl ether, dialkylphenoxy poly(ethyleneoxy) ethanol, available from Rhone-Poulenc as IGEPAL CA-210 IGEPAL CA-520, IGEPAL CA-720, IGEPAL CO-890, IGEPAL CO-720, IGEPAL CO-290, IGEPAL CA-210, ANTAROX 890, and ANTAROX 897. Other examples of suitable nonionic surfactants include a block copolymer of polyethylene oxide and polypropylene oxide, including those commercially available as SYNPERONIC PE/F, such as SYNPERONIC PE/F 108. Other examples of suitable anionic surfactants include sulfates and sulfonates, sodium dodecylsulfate (SDS), sodium dodecylbenzene sulfonate, sodium dodecylnaphthalene sulfate, dialkyl benzenealkyl sulfates and sulfonates, acids such as abitic acid available from Sigma-Aldrich, NEOGEN R, NEOGEN SC available from Daiichi Kogyo Seiyaku, combinations thereof, and the like. Other examples of suitable anionic surfactants include DOWFAX 2A1, an alkyldiphenyloxide disulfonate from Dow Chemical Company, and/or TAYCA POWER BN2060 from Tayca Corporation (Japan), which are branched sodium dodecyl benzene sulfonates. Other examples of suitable cationic surfactants, which are usually positively charged, include alkylbenzyl dimethyl ammonium chloride, dialkyl benzenealkyl ammonium chloride, lauryl trimethyl ammonium chloride, alkylbenzyl methyl ammonium chloride, alkyl benzyl dimethyl ammonium bromide, benzalkonium chloride, cetyl pyridinium bromide, C 12, C15, C17 trimethyl ammonium bromides, halide salts of quaternized polyoxyethylalkylamines, dodecylbenzyl triethyl ammonium chloride, MIRAPOL and ALKAQUAT, available from Alkaril Chemical Company, SANIZOL (benzalkonium chloride), available from Kao Chemicals, and the like, as well as mixtures thereof. Mixtures of any two or more surfactants can be used.

[0101] The optional surfactant can be present in any desired or effective amount, in embodiments, the surfactant is present in an amount of from about 0.01 to about 5 percent by weight, based on the total weight of the ink composition. It should be noted that the surfactants are named as dispersants in some cases.

[0102] The ink composition can further comprise additives. Optional additives that can be included in the ink compositions include biocides, fungicides, pH controlling agents such as acids or bases, phosphate salts, carboxylates salts, sulfite salts, amine salts, buffer solutions, and the like, sequestering agents such as EDTA (ethylenediamine tetra acetic acid), viscosity modifiers, leveling agents, and the like, as well as mixtures thereof.

[0103] The ink compositions herein can be prepared by any suitable or desired process, such as by simple mixing of the ingredients. One process entails mixing all of the ink ingredients together and optionally filtering the mixture to obtain an ink. Inks can be prepared by mixing the ingredients, heating if desired, and optionally filtering, followed by adding any desired additional additives to the mixture and mixing at room temperature with moderate shaking until a homogeneous mixture is obtained, in embodiments from about 5 to about 10 minutes. Alternatively, the optional ink additives can be mixed with the other ink ingredients during the ink preparation process, which takes place according to any desired procedure, such as by mixing all the ingredients, heating if desired, and optionally filtering.

[0104] In embodiments, a process herein comprises combining water, an optional co-solvent, an optional colorant, a polyester, and a polymer additive, wherein the polymer additive is selected from a member of the group consisting of styrene-butadiene, acrylonitrile-butadiene, acrylonitrile-butadiene-styrene, and combinations thereof, to form an aqueous ink composition.

[0105] In embodiments, a process herein comprises combining a sulfonated polyester resin, water, an optional co-solvent, an optional colorant, and a polymer additive as described herein to form an aqueous ink composition. In a specific embodiment, the inks are prepared as follows: 1) preparation of a sulfonated polyester; 2) preparation of a dispersion of a colorant optionally stabilized with a surfactant; 3) mixing of the sulfonated polyester with the colorant dispersion and polymer additive dispersion; and 4) addition of other components such as water, co-solvents, and optional additives.

[0106] In embodiments, a method of digital offset printing herein includes applying the ink composition of the present disclosure onto a re-imageable imaging member surface, the re-imageable imaging member having dampening fluid disposed thereon; forming an ink image; and transferring the ink image from the re-imageable surface of the imaging member to a printable substrate.

[0107] The ink composition in accordance with the present disclosure is not limited to use in digital offset printing. The ink composition disclosed herein may also be useful in conventional offset printing or hybrid conventional offset and digital offset printing systems. Nonetheless, the ink compositions of the present disclosure meet systems requirements that are unique to digital offset printing systems.

[0108] In embodiments, a process of digital offset printing herein comprises applying an ink composition onto a re-imageable imaging member surface at an ink take up temperature, the re-imageable imaging member having dampening fluid disposed thereon; forming an ink image; transferring the ink image from the re-imageable surface of the imaging member to a printable substrate at an ink transfer temperature; wherein the ink composition comprises water, an optional co-solvent, an optional colorant, a polyester, and a polymer additive, wherein the polymer additive is selected from a member of the group consisting of styrene-butadiene, acrylonitrile-butadiene, acrylonitrile-butadiene-styrene, and combinations thereof.

[0109] In embodiments, applying the ink composition comprises applying the ink composition using an anilox delivery system.

[0110] Any suitable substrate, recording sheet, or removable support, stage, platform, and the like, can be employed for depositing the ink compositions herein, including plain papers such as XEROX 4024 papers, XEROX Image Series papers, Courtland 4024 DP paper, ruled notebook paper, bond paper, silica coated papers such as Sharp Company silica coated paper, JuJo paper, HAMMERMILL LASERPRINT paper, and the like, glossy coated papers such as XEROX Digital Color Gloss, Sappi Warren Papers LUSTROGLOSS, and the like, transparency materials, fabrics, textile products, plastics, polymeric films, glass, glass plate, inorganic substrates such as metals and wood, as well as meltable or dissolvable substrates, such as waxes or salts, in the case of removable supports for free standing objects, and the like. In certain embodiments, the substrate is selected from the group consisting of paper, plastic, polymeric film, cardboard, paperboard, folded paperboard, Kraft paper, glass, glass plate, wood, metal, and combinations thereof. In a specific embodiments, the substrate is a label. The label can be selected from any of the aforementioned types of substrate. In embodiments, the substrate comprises food packaging, medicinal packaging, and the like. In certain embodiments, the ink compositions herein form an undercoat. In embodiment, the substrate comprises a member of the group consisting of food packaging, medicinal packaging, medical devices, cosmetic packaging, cosmetic tools, cosmetic products, and combinations thereof. In embodiments, the substrate comprises a three-dimensional substrate. In embodiments, the substrate comprises medical devices such as catheters, thermometers, cardiac stents, programmable pace makers, other medical devices, menus, food packaging materials, cosmetic tools and products, and any other desired three-dimensional substrate. In further embodiments, the substrate comprises customizable digitally printed ID codes, short-run printable materials three-dimensional medical and any other desired three-dimensional substrate.

EXAMPLES

[0111] The following Examples are being submitted to further define various species of the present disclosure. These Examples are intended to be illustrative only and are not intended to limit the scope of the present disclosure. Also, parts and percentages are by weight unless otherwise indicated.

Example 1

Highly Sulfonated Polyester Synthesis (7.5 Weight Percent Sulfonation.

[0112] A 5 gallon Parr reactor equipped with a mechanical stirrer, distillation apparatus and bottom drain valve was charged with dimethyl terephthalate (3.492 Kilograms), dimethyl-5-sulfo-isophthalate sodium salt (940 grams), 1,2-propanediol (2.9 Kilograms), diethylene glycol (449 grams) and FASCAT 4100 (7.2 grams). The mixture was heated under nitrogen flow (3 SCFH) to 120 C., after which stirring at 50 revolutions per minute (rpm) was initiated. The mixture was then heated at 0.5 C./minute for the next two hours until a temperature of 180 C. was attained, during which the methanol byproduct was collected in the distillation receiver. The mixture was then heated at a rate of 0.25 C., until a temperature of 210 C. was attained, during which both methanol and excess 1, 2-propanediol was collected in the distillation receiver. Vacuum was then applied gradually until 4.4 mm-Hg was attained at 210 C. over a 1 hour period. The mixture was then re-pressurized to atmospheric pressure with nitrogen, and the content was discharged through the bottom drain into a container. The product was then allowed to cool to room temperature overnight, followed by granulation using a FitzMill. The product displayed an onset glass transition temperature of 55.4 C., number average molecular weight of 1,326 grams/mole, a weight average molecular weight of 2,350 grams/mole, and a softening point of 135.9 C.

Examples 1-2

[0113] Formulation into Digital Offset Ink.

[0114] Examples 1 and 2 having the components as shown in Table 1 were formulated into an ink as follows.

TABLE-US-00001 TABLE 1 Example 1 Example 2 Example 3 Weight Mass Weight Mass Weight Mass Percent (grams) Percent (grams) Percent (grams) Sulfonated 30 22.5 30 22.5 30 18 Polyester Sulfolane 20 15 20 15 18 10.8 Diethylene 0 0 0 0 2 1.2 Glycol Pigment 45 33.75 45 33.75 30 18 Dispersion Nychem 5 3.75 5 3.75 20 12 ABS Dispersion Nychem 1581 1578 1 1578 1 Grade TOTAL 100 75 100 75 100 60

[0115] Sulfonated polyester is the sulfonated polyester having 7.5 percent sulfonation prepared as described above.

[0116] Nychem 1581 and 1578x1 dispersions are about 43-48.5% solids in water.

[0117] Pigment dispersion for Examples 1 and 2 is an aqueous cyan pigment dispersion with 13 percent solids. Pigment Dispersion for Example 3 is an aqueous cyan pigment dispersion with 33.3 percent solids.

[0118] To a 250 milliliter beaker fitted with a heating jacket and overhead mixer was added 45 grams of an aqueous 13% cyan pigment dispersion (13% solids) and heated to 90 C. Next, 20 grams of sulfolane is added. Sulfopolyester is gradually added to the heated dispersion. The mixture is covered with foil and allowed to mix for 20-30 minutes at 90 C., then allowed to cool to room temperature. The cooled mixture is then transferred to a 250 milliliter water-cooled beaker fitted with an overhead stirrer fitted with a Cowles blade and stirred. Finally, 5 grams of the nitrile dispersion is gradually added during mixing. The mixture is allowed to stir for 30-45 minutes in a water-cooled beaker to furnish the final digital offset lithography ink. The viscosity of the prepared inks is shown in FIG. 3.

[0119] Testing of Inks Containing Nitrile Latex on Lithographic Print Fixture.

[0120] The ink of Example 2 was tested on a digital offset printing fixture to evaluate the efficiency of ink transfer from the blanket under typical lithographic print conditions. An anilox roll was filled with ink, transferred to the blanket, then offset pressed onto Sterling Gloss #80 paper, followed by a second and third offset event between fresh paper and the previously inked blanket to monitor the residual ink that may remain on the blanket (chase sheet).

[0121] FIG. 4 shows the offset printing results for the 3 ink samples. Samples 1 and 2 showed 100% ink transfer with no residue ink observed on the chase sheet. Only a trace of ink was seen for sample 3, and only from the edges of the blanket. It is noted that transfer this complete, at 100%, has not been observed for UV inks using this fixture with bare blanket; these aqueous formulations display the highest transfer performance yet observed by our screening processes.

Robustness Testing.

[0122] Dried prints on coated paper were subjected to preliminary robustness testing. The results are summarized as follows.

[0123] The prints were robust to tape test, where Scotch tape was applied with pressure to the print surface and removed cleanly.

[0124] The prints were robust to a water swab test, where a cotton swab was dipped in water and rubbed with pressure across the print surface 20 times, with only a faint trace of coloration on the wet swab. After 20 double rubs, there was no evidence of ink removal.

[0125] A lithographic print was created on Kapton (polyimide film). The Kapton film was heated in an oven at 160 C. for 30 minutes. Samples were subjected to scratch testing, using a standardized scratch test, ASTM D-3359, Measuring Adhesion by Tape Test, using Elcometer 99 tape available from Elcometer USA. The rating system in ASTM D3359 ranges from 0 B to 5 B where at least 3 B adhesion results are preferred and 5 B adhesion results are most preferred. There was no evidence of ink removal, and the score was 5 B (0% ink removal). FIG. 5 shows the ABS additive ink print on Kapton substrate after subjecting to water rub and scratch testing.

[0126] It will be appreciated that variations of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims. Unless specifically recited in a claim, steps or components of claims should not be implied or imported from the specification or any other claims as to any particular order, number, position, size, shape, angle, color, or material.