Ink compositions

Aspects of the present invention relate to a process for the preparation of an ink which comprises mixing an ink vehicle, a colorant and a polyurethane resin emulsion; a process wherein the polyurethane resin emulsion is generated from the urethanization of (a) from about 50 to about 95 weight percent of a polyester polyol; and (b) from about 5 to about 45 weight percent of a polyisocyanate; and (c) from about 1 to about 15 weight percent of ionic groups and wherein the total of said components (a) to (c) is about 100 percent; a process wherein the polyester polyol is generated by the polycondensation of from about 0 to about 80 weight percent of a monocarboxylic acid, from about 5 to about 60 weight percent of a polycarboxylic acid, and from about 10 to about 80 weight percent of a polyol; a process wherein the polyurethane resin emulsion particles possesses a particle size of from about 0.05 microns to about 1 microns, or from about 0.1 microns to about 0.5 microns in volume average diameter; a process wherein the polyurethane resin emulsion possesses a viscosity at 25.degree. C. of from about 10 to about 20,000 centipoise (cPs), and or from about 50 to about 10,000 centipoise; a process wherein the polyurethane resin possesses a weight average molecular weight Mw of from about 1,500 to about 100,000, or from about 2,000 to about 45,000; a process wherein the polyurethane resin possesses a number average molecular weight Mn of from about 1,000 to about 70,000, or from about 1,000 to about 30,000; a process wherein the polyurethane resin emulsion possesses a hydroxyl number of from about 10 to about 300, or from about 20 to about 150 mg KOH/g; a process wherein the polyurethane resin possesses a carboxyl group content corresponding to an acid number of from about 5 to about 70, or from about 10 to about 40 mg KOH/g; a process wherein the polyurethane resin emulsion possesses urethane groups calculated as NH-O-O-, molecular weight, Mw of 59, of from about 2 to about 20, and or from about 5 to about 15 weight percent; a process wherein (a) is prepared by the polycondensation of from about 0 to about 80 weight percent of a monocarboxylic acid, from about 5 to about 60 weight percent of a polycarboxylic acid, and from about 10 to about 80 weight percent of a polyol, wherein said monocarboxylic acid is benzoic acid, tert-butylbenzoic acid, hexahydrobenzoic acid, saturated fatty acids of 2-ethylhexanoic acid, isononanoic acid, decanoic acid, dodecanoic acid, and stearic acid, unsaturated fatty acids such of soybean oil fatty acid, soya oil fatty acid, sorbic acid, and conjugated diene fatty acid, or mixtures thereof; wherein the polycarboxylic acid is di-, tri-, and/or tetracarboxylic acids of phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, maleic acid, succinic acid, fumaric acid, adipic acid, sebacic acid, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, maleic anhydride, succinic anhydride, or mixtures thereof, and wherein the polyol is ethylene glycol, propylene glycol, butanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, neopentyl glycol, pentaerythriol, trimethylpentanediol, or mixture thereof; the polyisocyanate (b) is 1-methyl-2,4-diisocyanato-cyclohexane, 1-methyl-2,6-diisocyanato-cyclohexane, 1,6-hexamethylene diisocyahate (HDI), 1 -isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane (IPDI), 2,4- or 2,6-diisocyanato-toluene (TDI), 4,4'-diisocyanatodicyclohexylmethane (Hl.sub.2 MDI), or 4,4'-diisocyanatodiphenyl-methane (MDI); and wherein (c) is obtained from 2,2-bis(hydroxymethyl)-alkanecarboxylic acids of dimethylolacetic acid, 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyfic acid, and 2,2-dimethylolpentanoic acid), dihydroxysuccinic acid, hydroxypivalic acid, and mixtures thereof; a process wherein the monocarboxylic acid selected for generation of the polyester polyol (a) are tert-butylbenzoic acid, stearic acid, or soybean oil fatty acid; wherein the polycarboxylic acids selected for the generation of the polyester polyol (a) is isophthalic acid, phthalic anhydride, or hexahydrophthalic anhydride; or wherein the polyol selected for generation of the polyester polyol (a) is 1,6-hexanediol, neopentyl glycol, pentaerythriol, or trimethylpentanediol; wherein the polyisocyanates (b) are 1 -methyl-2,4-diisocyanato-cyclohexane, 1 -methyl-2,6-diisocyanato-cyclohexane, and 1 -isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane (IPDI); wherein the ionic groups (c) were obtained from acids of 2,2-dimethylolpropionic acid and hydroxypivalic acid; a process wherein the polyurethane resin contained in the polyurethane emulsion is generated from the urethanization of from about 50 to about 95, or from about 65 to about 90 weight percent of a polyester polyol; from about 5 to about 45, or from about 5 to about 30 weight percent of a polyisocyanate; and from about 1 to about 15, or from about 3 to about 10 weight percent of an acid component that will enable incorporation of ionic groups; a process wherein the polyurethane resin emulsion is comprised of from about 17 to about 60 percent by weight of polyurethane resin, from about 0.1 to about 3 percent by weight of surfactant, and from about 33 to about 82 percent by weight of water; a process wherein the polyurethane resin is present in an amount of from about 20 to about 50 weight percent; a process wherein the total of all ink components is about 100 percent; a process wherein the colorant is a dye; a process wherein the colorant is a pigment; a process wherein the polyurethane emulsion contains water; a process wherein there is added to the ink an ink vehicle and ink additives; a process wherein the vehicle is water, a glycol, or a mixture of glycol's, or a mixture of water and a miscible organic component of ethylene glycol, propylene glycol, diethylene glycols, glycerine, dipropylene glycol, polyethylene glycol, or polypropylene glycols; a process utilizing ink additives of surfactants of poly(ethylene glycol) monolaurate, poly(ethylene glycol) monoricinoleate, poly(ethylene glycol) lanolin alcohol ether, poly(ethylene glycol) monooleate, poly(ethylene glycol) castor oil, poly(ethylene glycol) tetramethyl optionally decynediol, or poly(ethylene glycol) lanolin, and which surfactants are present in an amount of from about 0.01 to about 7 weight percent or parts based on the total ink components; a high resolution printing process comprising applying in imagewise fashion to a substrate an ink composition obtained by the process as illustrated herein; and wherein high is, for example, from about 300 to about 300 to about 1,000 dots per inch; a process wherein the substrate is paper, and there is selected a printer having at least one nozzle of a channel width or diameter ranging from about 10 to about 40 microns and intercolor bleed is minimized or eliminated, and wherein said printing process is optionally accomplished with a 600 spi ink jet printer with a radiant heat assisting drying process; a process for reducing or eliminating paper curl and avoiding or minimizing smear in a xerographic ink jet apparatus which comprises generating images in said apparatus and developing said images with the ink composition obtained by the process as illustrated herein; a process wherein the ionic groups are anionic groups or moieties; a process wherein the urethanization reaction is accomplished by heating a temperature of about 40 to about 140.degree. C., or from about 65 to about 130.degree. C.; a process wherein (a) is present in an amount of from about 65 to about 90 weight percent; (b) is present in an amount of from about 5 to about 30 weight percent; and (c) is present in an amount of from about 3 to about 10 weight percent; an ink comprised of a vehicle, a colorant, and a polyurethane resin; and wherein the resin can be generated from a polyurethane emulsion; an ink comprised of a polyurethane resin, colorant, vehicle, and wax; and wherein the emulsion can be optionally generated from condensation polymers obtained from a number of known waxes; ink compositions comprised of colorant, polymer, and certain additives; inks comprised of a major amount of a vehicle, like water, colorant, such as dye, pigment, or mixtures thereof, a polyurethane resin emulsion, and known ink additives, such as biocides, humectants, polymeric additives, stabilizer additives, and the like. The liquid vehicle is generally present in an amount of from about 50 to about 99 percent by weight, and preferably from about 55 to about 95 percent by weight, the colorant is generally present in an amount of from about 1 to about 20 percent by weight, and preferably from about 3 to about 10 percent by weight, the polyurethane resin emulsion is generally present in an amount of from about 0.1 to about 20 percent by weight, and preferably from about 0.5 to about 10 weight percent, a biocide, when selected is generally present in an amount of from about 0 to about 10 percent by weight, and preferably from about 0.001 to about 8 percent by weight, a humectant, when selected is generally present in an amount of from about 0 to about 50 percent by weight, and preferably from about 1 to about 30 percent by weight, a polymeric additive, when present, such as Gum Arabic, polyacrylate salts, polymethacrylate salts, polyvinyl alcohols, hydroxy propylcellulose, hydroxyethylcellulose, polyvinylpyrrolidinone, polyvinylether, starch, polysaccharides, polyethyleneimines derivatized with polyethylene oxide and polypropylene oxide is generally present in an amount of from about 0 to about 10 percent by weight, and preferably from about 0.001 to about 8percent by weight, a stabilizer additive when present such as a mixture of secondary alcohols reacted with ethylene oxide, polyethylene oxide, alkylphenoxy-polyethylene oxide, polyethylene oxide nonylphenyl ether (the primary function of the stabilizer, for example to adjust the surface or interfacial tension of the ink, and to enhance the stability of the ink) is generally present in an amount of from about 0 to about 5 percent by weight, and preferably from about 1 to about 3 percent by weight, based on the total amount of components in the ink. The inks in embodiments possess a latency of at least about 10 to about 80 or more seconds in, for example, a printer having at least one nozzle of a channel width or diameter ranging for example, from about 10 to about 40 microns, and wherein intercolor bleed is minimized or eliminated. An important measured property for an ink jet ink is the latency or decap time, which is the length of time over which an ink remains fluid in a printhead opening or nozzle when exposed to air and, therefore, capable of firing a drop of ink at its intended target. Latency is the maximum idling time allowed for ink to be jetted by a printer with a speed equal to or greater than 5 ms (equivalent to an ink traveling a distance of 0.5 millimeter in less than 100 As) without a failure. The latency test is operated with the printhead or nozzles uncovered or decapped, and generally at a relative humidity of 15 percent. The time interval is the longest length of time that the printhead, uncovered, will still fire a specified drop without drop displacement or loss of density. The longer the latency time rating, the more desirable the ink.

As the bubble begins to collapse, the ink remaining in the channel between the nozzle and bubble starts to move toward the collapsing bubble, causing a volumetric contraction of the ink at the nozzle and resulting in the separation from the nozzle of the bulging ink as a droplet.

Dye-based ink jet inks suffer from deficiencies in waterfastness and lightfastness after being printed on various substrates.

Some cosolvents that can be selected as clogging inhibitors cause destabilization of pigment dispersions and, therefore, are not usually effective in pigmented inks.