WO2009104042A1

WO2009104042A1 - Inks comprising thickeners and methods for making and using the same

Info

Publication number: WO2009104042A1
Application number: PCT/IB2008/000826
Authority: WO
Inventors: Laszlo Garamszegi; Marco Ribezzo; Pascal Gruffel; Gilles Dolivo; Martial Blanc; Manuel Golder
Original assignee: Sensient Imaging Technologies Sa
Priority date: 2008-02-19
Filing date: 2008-02-19
Publication date: 2009-08-27

Abstract

An ink for printing on a substrate contains a colorant, a hydrophobic ethoxylated urethane polymer, and an amphiphilic polymer. The ink may be made by mixing the hydrophobic ethoxylated urethane polymer and the amphiphilic polymer in the ink to provide an ink having a particular viscosity. The ink may be used in ink jet printers and jetted onto a variety of substrates, including textiles.

Description

INKS COMPRISING VISCOSITY MODIFIERS AND METHODS FOR MAKING AND USING THE SAME

BACKGROUND

[0001] Ink-jet printing is a non-impact method for producing images by deposition of ink droplets on a substrate with high droplet speed. Ink-jet fluids used in ink-jet printing meet various performance requirements (e.g., viscosities, surface tensions, smear resistance, solubilities, drying times, storage stability) that make them suitable for use with ink-jet printers. Some inks have viscosities that are too low to permit the inks to be successfully jetted onto a surface. Still other ink jet inks are incapable of being stored without negatively influencing equipment stability or nozzle clogging.

SUMMARY

[0002] In one embodiment, the invention provides an ink for printing on a substrate which includes a colorant, a hydrophobic ethoxylated urethane polymer, and an amphiphilic polymer.

[0003] In another embodiment the invention provides a method of manufacturing an ink, which includes the steps of incorporating a hydrophobic ethoxylated urethane polymer and an amphiphilic polymer in the ink, to provide an ink having a viscosity of about 10 mPas to about 14 mPas.

[0004] In another embodiment the invention provides a method of printing in which an ink jet printer is used to jet an ink comprising a colorant, a hydrophobically modified polyurethane thickening agent, and an amphiphilic polymer on a substrate.

[0005] Other aspects of the invention will become apparent by consideration of the detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Fig. 1 is a microscopic image of droplets formed by the ink of Example 1.

[0007] Fig. 2 is a microscopic image of droplets formed by the ink of Example 2. [0008] Fig. 3 is a microscopic image of droplets formed by the ink of Example 3.

DETAILED DESCRIPTION

[0009] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

[0010] It also is understood that any numerical range recited herein includes all values from the lower value to the upper value. For example, if a concentration range is stated as 1% to 50%, it is intended that values such as 2% to 40%, 10% to 30%, or 1% to 3%, etc., are expressly enumerated in this specification. These are only examples of what is specifically intended, and all possible combinations of numerical values between and including the lowest value and the highest value enumerated are to be considered to be expressly stated in this application.

[0011] In one aspect, the present invention relates to ink-jet ink formulations comprising a colorant, a hydrophobic ethoxylated urethane polymer, and an amphiphilic polymer modulator. Ink-jet formulations of the present invention may do at least one of the following: 1) provide uniform, bleed-free images, when printed both on a plain and color background, with high resolution and high density on print media; 2) prevent nozzle clogging which typically occurs due to drying of the ink at a distal end of a nozzle; 3) exhibit good light resistance and water resistance with appropriate fixation treatment; 4) demonstrate good long-term storage stability without negatively influencing equipment stability; and 5) demonstrate print characteristics which are independent of the textile quality. Moreover, the inks of the present invention may overcome the difficulties associated with relatively viscous inks to achieve stable high speed droplet formation in a small range droplet velocity deviation and angle deviations, as well as good outline of the recorded pictures, which results in smooth dots and minimal blotting of the dotted ink. The present invention provides ink-jet ink formulations that can be printed onto the surfaces of a variety of textiles using industrial printers.

[0012] The ink compositions of the present invention are suitably prepared by combining a colorant, a hydrophobic ethoxylated urethane polymer viscosity modifier, and an amphiphilic polymer modulator in a suitable vehicle. The ink composition may comprise an aqueous vehicle, a water-miscible organic solvent, and a water-miscible organic co-solvent.

[0013] The aqueous vehicle may comprise water or water in combination with one or more water-soluble organic solvents. The type of water used in the ink composition is not limited. However, distilled water, deionized water, super pure water, and ultrafiltrate may be used to minimize the introduction of impurities. The amount of water (by weight) in the ink composition may range from about 40% to about 80%, particularly from about 45% to about 70%, and more particularly from about 50% to about 65%. The inks may comprise at least about 5%, at least about 10%, at least about 20%, at least about 25%, at least about 30%, at least about 40%, or at least about 50% water.

[0014] Water-soluble organic solvents may be combined with water to make up the aqueous vehicle. Water-soluble organic solvents may include alcohol ethers, esters, polyols, nitrogen- containing cyclic compounds, and combinations thereof. Examples include, without limitation, alcohols having 1 to 5 carbon atoms, such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol and n- pentanol; polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-propylene glycol, isopropylene glycol, butylene glycol, isobutylene glycol, 1,4-butanediol, 1,3-butanediol, 1,2-propanediol, 1,5- pentanediol, 1,6-hexanediol, 1,2-hexanediol, 1,2,6-hexanetriol, trimethylolpropane, glycerin, polyethyleneglycol, mesoerythritol and pentaerythritol; ketones and ketone alcohols such as acetone and diacetone alcohol; ethers such as tetrahydrofuran and dioxane; lower alkyl ethers of polyhydric alcohols, such as ethylene glycol monomethyl (or monoethyl) ether, diethylene glycol monomethyl (or monoethyl) ether and triethylene glycol monomethyl (or monoethyl) ether; lower dialkyl ethers of polyhydric alcohols, such as triethylene glycol dimethyl (or diethyl) ether and tetraethylene glycol dimethyl (or diethyl) ether; nitrogen-containing solvents such as pyrrolidone, N-methyl-2-pyrrolidone, l,3-dimethyl-2-imidazolidinone, cyclohexylpyrrolidone, monoethanolamine, diethanolamine, triethanolamine, dimethylformamide, dimethylacetamide, and NN-dimethylaminoethanol; sulfur-containing solvents such as thiodiethanol, thiodi glycerol, sulfolane, and dimethylsulfoxide; propylene carbonate, and ethylene carbonate, sugars and derivatives thereof such as glucose, fructose, galactose, mannose, and xylose; sugar- alcohols; an oxyethylene adduct of glycerin; and an oxyethylene adduct of diglycerin. The water-soluble organic solvents may be used alone or in combination. If a mixture of water and a water-soluble organic solvent is used, the amount of organic solvent (by weight) in the ink composition may range from about 5% to about 50%, particularly from about 10% to about 40%, and more particularly from about 15% to about 30%. Suitably, the ink contains at least about 1%, at least about 5%, at least about 10%, or at least about 15% of an organic solvent.

[0015] Preservatives, such as biocides and fungicides, may also be added to the ink composition. Examples of suitable preservatives include sodium benzoate, pentachlorophenol sodium, 2-pyridinethiol-l -oxide sodium, sodium sorbate, sodium dehydroacetate, benzisothiazolinone, l,2-dibenzothiazolin-3-one, methylisothiazolinone and chloromethylisothiazolinone. Commercially available biocides include UCARCIDE ^R 250 (available from Union Carbide Company), PROXEL^® CRL, PROXEL ^® BDN, PROXEL ^® GXL, PROXEL ^® XL-2, PROXEL^® TN (available from Arch Chemicals, Smyrna, GA ), DOWICIDES^® (Dow Chemical, Midland, Mich.), NUOSEPT^® (HuIs America, Inc., Piscataway, N. J.), OMIDINES^® (Olin Corp., Cheshire, Conn.), NOPCOCIDES^® (Henkel Corp., Ambler, Pa.), XBINX^® 19G (PMC Specialties Group, Inc., Cincinnati, OH), BIOBAN™ (available from Dow Chemical, Midland, Mich.), PREVENTOL® (Lanxess, Germany) and TROYSANS^® (Troy Chemical Corp., Newark, N.J.). The preservatives may be used alone or in combination. The amount of preservatives (by weight) in the ink composition may range from about 0.01% to about 0.5%, particularly from about 0.05% to about 0.3%, and more particularly from about 0.1% to about 0.2%.

[0016] The colorant may comprise one or more dyes, pigments, or combinations thereof. The dye can be either soluble or insoluble in the aqueous vehicle. In one embodiment, the pigment or dye is insoluble in the aqueous vehicle. Such colorants can be selected from the group of pigments and dyes generally useful in inkjet printing. Examples of dyes may include, but are not limited to, C. I. Direct Black 17, 19, 32, 51, 71, 108, 146, 154, 168; C. I. Direct Blue 6, 22, 25, 71, 86, 90, 106, 199; C. I. Direct Red 1, 4, 17, 28, 83, 227; C. I. Direct Yellow 12, 24, 26, 86, 98, 132, 142; C. I. Direct Orange 34, 39, 44, 46, 60; C. I. Direct Violet 47, 48; C. I. Direct Brown 109; C. I. Direct Green 59; C. I. Acid Black 2, 7, 24, 26, 31, 52, 63, 112, 118; C. I. Acid Blue 9, 22, 40, 59, 93, 102, 104, 113, 117, 120, 167, 229, 234; C. I. Acid Red 1, 6, 32, 37, 51, 52, 80, 85, 87, 92, 94, 115, 181, 256, 289, 315, 317; C. I. Acid Yellow 11, 17, 23, 25, 29, 42, 61, 71; C. I. Acid Orange 7, 19; and C. I. Acid Violet 49. Disperse dyes are also suitably used as the colorant. Suitable disperse dyes include, but are not limited to, commercially available dyes such as C.I. Disperse Yellow 3, 23, 42, 54, 64, 71, 79, 82, 114, 119, 163, 211, C.I. Disperse Orange 3, 25, 29, 30, 44, 73, C.I. Disperse Red 1, 5, 11, 13, 50, 60, 73, 74, 82, 91, 92, 135, 152, 153, 167, 177, 179, 277, 343, 356, 362, C.I. Disperse Violet 1, 8, 26, 28, 33, 63, 77, 93, C.I. Disperse Blue 3, 56, 60, 73, 77, 79, 87, 102, 148, 165, 183, 257, 284, 366, 367, C.I. Disperse Green 9, and C.I. Disperse Brown 1. The dyes as described above may be used singly. Alternatively, two or more of the dyes as described above may be used in combination. The amount of dye (by weight) in the ink composition may range from about 0.01% to about 20%, particularly from about 0.1% to about 15%, and more particularly from about 0.5% to about 7%.

[0017] Any one of the organic pigments may be used as a colorant. The pigment is not specifically limited. Examples of suitable pigments include, but are not limited to, carbon black, azo pigment, phthalocyanine pigment, anthraquinone pigment, quinacridone pigment, thioindigo pigment, triphenylmethane lake pigment, and oxazine lake pigment. Diketo-pyrrolo-pyrrole (DPP) pigments also are useful in inks of the present invention and include those described, for example, in United States Patent Nos.4,579,949 and 4,415,685, each of which is here incorporated by reference. Suitable pigments having yellow colors include, for example, C. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 19, 65, 74, and 83 and Solvent Yellow 33. Those having red colors include, for example, C. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 49, 50, 51, 52, 53, 55, 60, 64, 83, 87, 88, 89, 90, 112, 114, 122, 123, and 163. Those having blue colors include, for example, C. I. Pigment Blue 2, 3, 15, 16, 22, and 25. Those having black colors include, for example, C. I. Pigment Black 1 and 7. Those capable of self dispersion, which is subjected to a surface-modifying treatment and which can be stably dispersed even when no dispersing agent is used, are also suitable. The pigments as described above may be used singly. Alternatively, two or more of the pigments as described above may be used in combination. The amount of pigment (by weight) in the ink composition may range from about 0.1% to about 20%, particularly from about 0.2% to about 15%, and more particularly from about 0.5% to about 7%.

[0018] Pigments and dyes not soluble in the aqueous vehicle may be suitably provided as a concentrated mill base, which may then be diluted to the appropriate concentration in the ink. The mill base may suitably comprise a water and water-miscible solvent mixture wherein the water- miscible solvent is present at about 10% to about 80% concentration (by weight), more particularly at about 5% to about 20% concentration (by weight). The mill base may comprise a non-ionic dispersant. Suitably, the non-ionic dispersant has a molecular weight above 1000. Examples of suitable non-ionic dispersants include, but are not limited to, block POE-POP block co-polymers, for example, the PLURONIC® series commercially available from BASF Corporation, USA; block co-polymers with one or more pigment affinic groups, for example, the DISPERB YK® series commercially available from BYK Chemie, USA; and polymeric dispersants, for example the SOLSPERSE® series commercially available from Lubrizol Corporation, USA. The non-ionic dispersant may be present in a concentration (by weight) of about 2% to about 30%, particularly about 5% to about 15%. In one embodiment of the present invention, the colorant, such as a dispersed dye or pigment, is combined with the mill base and milled to sub-micron size. Suitably the dispersed dyes or pigments may be milled to an average primary particle size of about 70 nm to about 400 nm. As used herein, the term "average primary particle size" refers to the values measured in water at 25⁰C using a light scattering analysis (such as carried out with a ZETASIZER® Nano S90, commercially available from Malvern Instruments Ltd., Worcestershire, UK).

[0019] In some embodiments, the ink may contain a polymeric binder or a mixture of polymeric binders. The polymeric binders may contribute to achieving a good rubfastness of the ink. Examples of polymeric binders include, but are not limited to, a polyurethane dispersion, a UV curable polyacrylate, or a combination thereof. Suitably, the polymeric binder is present from about 1% to about 30%, particularly from about 2% to about 25%, and more particularly from about 4% to about 20%. [0020] Surfactants may be added to the aqueous medium to reduce the surface tension of the ink composition. The surfactants may be anionic surfactants, non-ionic surfactants and/or cationic surfactants. Suitable surfactants may include those listed below and in U.S. Patent No.

5,116,409 issued May 26, 1992, U.S. Patent No. 5,861,447 issued January 19, 1999, and U.S.

Patent No. 6,849, 111 issued February 1 , 2005, each of which is hereby incorporated by reference.

[0021] The anionic surfactants include, but are not limited to, lignosulfonate, alkylbenzene sulfonate, an alkylphenyl sulfonate, an alkylnaphthalene sulfonate, a higher fatty acid salt, a sulfate ester of a higher fatty acid ester, a sulfonate of a higher fatty acid ester, a sulfate ester and a sulfonate of a higher alcohol ether, a higher alkylsulfosuccinate, a polyoxyethylene alkylether carboxylate, a polyoxyethylene alkylether sulfate, an alkylphosphate, and a polyoxyethylene alkylether phosphate. Specific examples of the anionic surfactant include dodecylbenzene sulfonate, isopropylnaphthalene sulfonate, monobutylphenylphenol sulfonate, monobutylbiphenyl sulfonate, monobutylbiphenyl sulfonate, and dibutylphenylphenol disulfonate. For example, UFOXANE® (a lignosulfonate commercially available from Boregaard Lignotech, Norway) may be used.

[0022] The nonionic surfactants include, but are not limited to, a polyoxyethylene alkyl ether, a polyoxyethylene alkyl phenyl ether, a polyoxyethylene fatty acid ester, a sorbitan fatty acid ester, a polyoxyethylene sorbitan fatty acid ester, a polyoxyethylene sorbitol fatty acid ester, a glycerin fatty acid ester, a polyoxyethylene glycerin fatty acid ester, a polyglycerin fatty acid ester, a cane sugar fatty acid ester, a polyoxyethylene alkylamine, a polyoxyethylene fatty acid amide, an alkylalkanolamide, a polyethylene glycol polypropylene glycol block copolymer, acetylene glycol, and a polyoxyethylene adduct of acetylene glycol, and specific examples of the nonionic surfactant include polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, a polyoxyethylene alkyl ether, a polyoxyethylene fatty acid ester, a sorbitan fatty acid ester, a polyoxyethylene sorbitan fatty acid ester, fatty acid alkylolamide, a polyethylene glycol/polypropylene glycol block copolymer, acetylene glycol, and a polyoxyethylene adduct of acetylene glycol. [0023] Specific examples of the water-soluble cationic surfactants used in the present invention include, but are not limited to, inorganic or organic acid salts of an aliphatic primary amine such as octylamine, laurylamine, stearylamine, oleylamine, tetradecylamine, hexadecylamine, coconut amine, coconut alkylamine, tallow amine, cured tallow alkylamine, soybean alkylamine and the like; inorganic or organic acid salts of an aliphatic secondary amine such as distearylamine, dioleylamine, di-coconut alkylamine, di-cured tallow alkylamine and the like; inorganic or organic acid salts of aliphatic tertiary amine such as dimethyloctylamine, dimethyldecylamine, dimethylaurylamine, dimethylmyristylamine, dimethylpalmityl amine, dimethylstearylamine, dilaurylmonomethylamine, dioleylmonomethylamine, trioctylamine, dimethyl coconut amine, coconut alkyldimethylamine, tallow alkyldimethylamine, cured tallow alkyldimethylamine, soybean alkyldimethylamine, di-coconut alkylmonomethylamine, di-cured tallow alkylmonomethylamine and the like; aliphatic quaternary ammonium salts such as tetramethylammonium chloride, tetraethylammonium chloride, tetrapropylammonium chloride, tetrabutylammonium chloride, lauryltrimethylammonium chloride, trioctylmethylammonium chloride, 3-chloro-2-hydroxypropyltrimethylammonium chloride, docosenyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, octadecyltrimethylammonium chloride, coconut alkytrimethylammonium chloride, tallow alkyltrimethylammonium chloride, octadecyldimethyl (3-trimethoxysilylpropyl)ammonium chloride and the like; aromatic quaternary ammonium salts such as benzyltrimethylammonium chloride, benzyltriethylammonium chloride, benzyltributylammonium chloride, benzyltrimethylammonium chloride, phenyltrimethylammonium chloride, cetyldimethylbenzylammonium chloride and the like; pyridinium salt type compounds (e.g., octylpyridinium chloride, cetylpicolinium chloride), imidazoline type cationic compounds (e.g., 2-heptadecenyl-hydroxyethylimidazolium chloride), benzotonium chloride, ethylene oxide added type quaternary ammonium salts (e.g., polyoxyethylenetrimethylammonium chloride), hydrochloride or acetate of aliphatic amides; salt of polyethylenepolyamine aliphatic amides; salt of urea condensate of polyethylenepolyamine aliphatic amides; quaternary ammonium salt of urea condensate of polyethylenepolyamine aliphatic amides; and N,N-dialkylmorphonium salts; and the like. [0024] Other suitable surfactants include a silicone surfactant such as an oxyethylene adduct of polysiloxane, a fluorinated surfactant such as a perfluoroalkylcarboxylate, a perfluoroalkylsulfonate, or an oxyethyleneperfluoroalkyl ether. A biosurfactant such as spicrispolic acid, rhamnolipid, or lysolecithin may also be used.

[0025] Among the above described surfactants, surfactants each having an unsaturated bond and surfactants each having a secondary or tertiary alkyl group may be used. Examples of the surfactant each having an unsaturated bond include alkyl ether derivatives of unsaturated alcohols such as oleyl alcohol, elaidyl alcohol, linoleyl alcohol, linolenyl alcohol, 2- heptanedecene-1-ol, and acetylene alcohol; and alkyl ester derivatives of unsaturated fatty acids such as lauroleic acid, myristoleic acid, oleic acid, linoleic acid, linolenic acid, dodecynoic acid, and octadecynoic acid.

[0026] Examples of the surfactant each having secondary or tertiary alkyl group include alkyl ether derivatives of branched alcohols such as 2-ethylhexyl alcohol, 2-octanol, 2-hexadecanol, and 2-octadecanol; and alkyl esters of branched fatty acids such as methylheptadecanoic acid, methylpentadecanoic acid, and methyloctadecanoic acid.

[0027] Suitable surfactants include those commercially available under various well-known tradenames, such as the PLURONIC ^R series (BASF Corporation, Parsippany, N.J.), the TETRONIC^® series (BASF Corporation, Parsippany, N.J.), the ARQU AD^® series (Akzo Chemical Inc., Chicago, 111.), the TRITON" series (Union Carbide Corp., Danbury, Conn.), the SURFONIC ^R series (Texaco Chemical Company, Houston, Tex.), the ETHOQUAD ^R series (Akzo Chemical Inc., Chicago, 111.), the ARMEEN^® series (Akzo Chemical Inc., Chicago, 111.), the ICONOL^® series (BASF Corporation, Parsippany, N.J.), the SURFYNOL^® series (Air Products and Chemicals, Inc. Allentown, Pa.), and the ETHOMEEN ^R series (Akzo Chemical Inc., Chicago, 111.), to name a few. The surfactants may be used alone or in combination. The amount of surfactant (by weight) in the ink composition may range from about 0.01% to about 20%, particularly from about 1% to about 15%, and more particularly from about 2% to about 8%.

[0028] To have good jetting ability for certain types of print heads, inks having relatively high viscosities are desired. The jetting ability or jettability of an ink is the ability of the ink to be jetted over time at a uniform velocity and drop volume, without misdirection or clogging of the ink jet nozzles. Inks of the present invention have good jetting ability. As used herein, the term "good jetting ability" means that when jetted, the ink has a velocity deviation of less than 7%, an angle deviation of no more than 0.5° and a constant drop volume after 4 x 10⁸ droplets are ejected from a nozzle. Suitably, the nozzle of an ink jet printer will substantially not clog, will maintain an angle deviation of no more than 0.5°, will maintain a velocity deviation of less than 7%, and/or will maintain a constant drop volume after at least about 200 g, at least about 300 g, at least about 400 g, at least about 500 g, at least about 600 g, at least about 800 g, at least about 1 kg, or at least about 1.5 kg of ink has been jetted through the nozzle.

[0029] For instance, ink formulations of the present invention may have a viscosity of about 5 to about 20 mPas particularly about 8 to about 16 mPas, and more particularly about 10 to about 14 mPas in the temperature range of about 20 ⁰C to about 45 ⁰C. It is desirable in some embodiments to match the viscosity with the conditions of the print head, such as driving voltages, driving frequencies, and nozzle diameters of piezoelectric oscillator printers. Inks of the present invention are compatible with commercial drop-on-demand piezoelectric print heads (such as those found in U.S. Patent No. 5,265,315, U.S. Patent No. 5,502,467, U.S. Patent No. 5,659,346, WO 2004/005030, and WO 2005/079500, US2005/185030, each of which is hereby incorporated by reference in its entirety). These printheads apply a large pressure pulse which demands a relatively high viscosity (about 5 to about 20 mPas) with the proper surface tension (about 25 to about 60 dyne/cm) for drop ejection with a droplet ejection frequency of typically 10 kHz or more.

[0030] Ink formulations of the present invention comprise a viscosity modifier, such as a hydrophobic ethoxylated urethane (HEUR) polymer. Specific examples of HEUR polymers include, without limitation, TEGO® ViscoPlus 3000, TEGO® ViscoPlus 3010 US (both commercially available from Tego, Hopewell, VA), and RHEOLATE® FXl 070 (commercially available from Elementis Specialties, Hightstown, NJ). Suitably, the HEUR polymer modifies the high shear rate properties of the ink. Modifying the high shear rate properties of the ink facilitates the stable formation of high speed droplets within in a small range of droplet velocities. Inks of the present invention may suitably be used in an ink-jet print head which applies a high shear rate in the range of 10,000 to 100,000 1/s for droplet ejection. The HEUR polymer may suitably have a low shear viscosity at low shear rates and an adequately high shear viscosity at high shear rate.

[0031] HEUR polymers are hydrophobically modified water-soluble polymers which may build viscosity through transient polymer association. Without being limited by any theory, it is believed that HEUR polymers are attractive at a higher shear rate. The hydrophobic groups form locally phase-separated entities which resemble micelles. This occurs above the critical micelle concentration. At a higher concentration the micelles aggregate through a rearrangement of looping chains to bridging chains (critical aggregation concentration). The looped chains are mechanically inactive. Inks containing a HEUR polymer may have a lower viscosity at lower shear rate. Without being limited by any theory, it is believed that shear thinning is not accompanied by changes in the structure of the micelles. The chain-end pull out of the bridged chains may dissipate the mechanical energy of high shear or extensional forces without degrading the polymer. This effect causes shear thinning but it is less extensive than in the case of other types of thickeners. It is believed that the HEUR polymer associates with the dye or pigment particles and participates in the stabilization of the colloidal system. Suitably, this stabilization occurs especially at high shear rate, such as above about 10,000 to about 100,000 1/s, where the shear rate induced particle separation or particle vibration could increase viscosity undesirably. It is believed that the HEUR polymer may shift the shear-induced shear thickening range above the operation shear rates of industrial print heads.

[0032] The amount of HEUR polymer (by weight) in the ink composition may range from at least about 0.05%, at least about 0.1%, at least about 0.2%, at least about 0.3%, at least about 0.4%, at least about 0.5%, or at least about 1%, and less than about 25%, less than about 20%, less than about 15%, less than about 10%, less than about 7.5%, or less than about 6%. For example, the amount of HEUR polymer (by weight) in the ink composition may range from between about 0.1% to about 20%, from about 0.1% to about 10%, or from about 0.5% to about 6%.

[0033] The ink composition of the present invention also includes a viscosity modulator, such as an amphiphilic polymer. The amphiphilic polymer may be used alone or in combination with other viscosity modulators. Suitable amphiphilic polymers include an amphiphilic long chain polymer, an amphiphilic block copolymer, an amphiphilic comb-like copolymer, an amphiphilic gradient copolymer, or a combination thereof. The amphiphilic polymer suitably comprises a polyoxyethylenated long chain amine, polyoxyethylenated alkyphenol, polyoxyethylenated alcohol, polyoxyethylenated carboxylic acid and its aliphatic and aromatic ester, polyoxyethylenated polyacrylic acid and its alkyl ester, alkylated polyether, polyalcohol, aryl- and polyetheramine and its alkylated and arylated derivative, styrene/acrylate acryclic acid copolymer, polyoxyethylenated sorbitol ester, polyoxyethylenated alkanolamide, poly(ethylene oxide-co-propylene oxide), maleic acid/vinyl polyether copolymer, styrene-maleic acid copolymer, a functionalized derivative of all of the above, and combinations thereof. Specific examples of the second modulator may include, but are not limited to, TEGO® Dispers 752W maleic acid/vinyl polyether copolymer (commercially available from Tego, Hopewell; VA ), DISPERB YK® 190 non-ionic copolymer with carboxyl groups (commercially available from BYK Chemie, Wallingford, CT), ZETASPERSE™ 1400 acrylate graft copolymer (commercially available from Air Product GmbH, Allentown; PA), SYMPERONIC® PE/L44 and PE/L64 (commercially available from Uniqema, Chicago; IL), PLURONIC® PE 10500 block copolymer of ethylene oxide and propylene oxide (commercially available from BASF, Parsippany, NJ. , USA), and JEFFSPERSE® X3204 non-ionic comb-polymer (commercially available from Huntsman, Salt Lake City).

[0034] The amount of amphiphilic polymer modulator in the ink composition may range from at least about 0.5%, at least about 1%, at least about 2%, at least about 3%, at least about 4%, at least about 5%, or at least about 8%, and less than about 25%, less than about 20%, less than about 17%, less than about 15%, less than about 14%, or less than about 12%. For example, the amount of the modulator (by weight) in the ink composition may range from between about 1% to about 20%, particularly from about 5% to about 15%, and more particularly from about 8% to about 12%.

[0035] The amphiphilic polymer modulates or reduces the high viscosity of the ink achieved from the presence of the HEUR polymer. Without being limited by any theory, it is believed that the amphiphilic polymer contains hydrophobic and hydrophilic blocks and balanced block sizes to contribute to the micellization of the hydrophobic points of the HEUR polymer viscosity modifier. Strong interaction as well as strong viscosity modulation is obtained when the hydrophobic part of the amphiphilic polymer attaches strongly to the hydrophobic part of the HEUR polymer viscosity modifier in the carrier medium of the ink. Suitably, the amphiphilic polymer modulator has one or more attached structures which are attracted by hydrophobic attraction between the modulator and the HEUR polymer viscosity modifier. It is believed that the unique structure of the HEUR polymer associated with the amphiphilic polymer modulator avoids the buildup of a dense and strong network.

[0036] In some embodiments, the ink composition comprises a second modulator. The second modulator is suitably a water soluble organic co-solvent. Examples of a second modulator may be, without limitation, alcohols having 1 to 5 carbon atoms, such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec -butyl alcohol, tert-butyl alcohol, isobutyl alcohol and n-pentanol; polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-propylene glycol, isopropylene glycol, butylene glycol, isobutylene glycol, 1,4-butanediol, 1,3-butanediol, 1,2-propanediol, 1,5-pentanediol, 1,6-hexanediol, 1 ,2-hexanediol, 1,2,6- hexanetriol, trimethylolpropane, glycerin, polyethyleneglycol, mesoerythritol and pentaerythritol; ketones and ketone alcohols such as acetone and diacetone alcohol; ethers such as tetrahydrofuran and dioxane; lower alkyl ethers of polyhydric alcohols, such as ethylene glycol monomethyl (or monoethyl) ether, diethylene glycol monomethyl (or monoethyl) ether and triethylene glycol monomethyl (or monoethyl) ether; lower dialkyl ethers of polyhydric alcohols, such as triethylene glycol dimethyl (or diethyl) ether and tetraethylene glycol dimethyl (or diethyl) ether; nitrogen-containing solvents such as pyrrolidone, N-methyl-2-pyrrolidone, l,3-dimethyl-2-imidazolidinone, cyclohexylpyrrolidone, monoethanolamine, diethanolamine, triethanolamine, dimethylformamide, dimethylacetamide, and NN-dimethylaminoehtanol; sulfur- containing solvents such as thiodiethanol, thiodiglycerol, sulfolane, and dimethylsulfoxide; propylene carbonate, and ethylene carbonate, sugars and derivatives thereof such as glucose, fructose, galactose, mannose, and xylose; sugar-alcohols; an oxyethylene adduct of glycerin; and an oxyethylene adduct of diglycerin. The amount of second modulator (by weight) in the ink composition may range from about 0.1% to 50%, particularly from about 5% to about 40%, and more particularly from about 15% to about 30%. [0037] The combination of the HEUR polymer viscosity modifier and the amphiphilic polymer modulator in the inks of the present invention may yield certain advantages. The thickening effect of some viscosity modifiers, such as hydrophobically modified alkali swellable emulsions (HASE) and alkali swellable emulsions (ASE), varies greatly as the pH increases or decreases. HASE and ASE thickeners are based on acrylic polymers with the carboxylic acid group further modifier with hydrophobic groups. Without being limited by any theory, it is believed that when HASE and ASE thickeners are incorporated in water, the system is acidic and no thickening occurs. However, when the carboxyl groups are neutralized with alkaline additives, HASE and ASE thickeners may swell and produce a viscosity increase. By using viscosity modifiers other than HEUR polymers, without the use of modulators, the pH of an ink must be stabilized and adjusted to an alkali value. This can be problematic because some dyes or dispersions are not stable at alkali pH values. Inks of the present invention may permit inks to formulated using colorants that are stable at any pH, including colorants that are stable at neutral (for example at a pH of about 6 to about 8), acidic (for example at a pH of about 3 to about 6) or slightly basic pHs (for example at a pH of about 7 to about 10). Accordingly, inks can be formulated with colorants that are stable, for example, at a pH of less than about 4, less than about 5, less than about 6, less than about 7, less than about 8, less than about 9, or less than about 10.

[0038] Suitably, the thickening effect of the HEUR polymer is only slightly pH dependent, such that the inks may be formulated to be at any pH. For instance, neutral inks are used in some instances to prevent corrosion of the print head. Suitably, inks containing a HEUR polymer and an amphiphilic polymer do not require a pH modifier or buffer. The inks of the present invention may comprise substantially no pH modifier and/or buffer. Buffers and pH modifiers suitable for adjusting the pH of inks are known in the art. Examples of pH modifiers or buffers include, without limitation, ammonia, sodium hydroxide, potassium hydroxide, or an organic amine base such as triethylamine, ethanolamine, diethanolamine, triethanolamine, dimethylaminoethanol, 1- (dimethylamino)-2-propanol, or 2-amino-2-methyl-l-propanol. Suitably, the ink contains (by weight) less than about 0.5%, less than about 0.25%, less than about 0.1%, less than about 0.05% or less than about 0.01% of a pH modifier, or no pH modifier at all. Suitably, the ink contains (by weight) less than about 0.5%, less than about 0.25%, less than about 0.1%, less than about 0.05% or less than about 0.01% of a pH buffer, or no pH buffer at all. A stable dispersion may be suitably achieved in inks of the present invention with dyes and/or pigments at a variety of pH values. The pH of the ink composition may range from at least about 4, at least about 5, at least about 6, or at least about 6.5, and less than about 12, less than about 11, less than about 10, less than about 9, or less than about 8. For example, the pH of the ink composition may range from about 4 to about 12, particularly from about 5 to about 11, more particularly from about 6 to 10.

[0039] Inks of the present invention, comprising a HEUR polymer and an amphiphilic polymer suitably have a viscosity that is stable over a wide pH range. For example, inks of the present invention may be formulated to have a viscosity of about 10 mPas to about 14 mPas that is maintained within that range over a pH from about 4 to about 11, from about 5 to about 10 or from about 6 to about 9. Suitably, the viscosity of the ink changes by less than about 5 mPa, less than about 4 mPas, less than about 3 mPas, less than about 2 mPas or less than about 1 mPas, when the pH changes from about 3, about 4, about 5 or about 6 to about 12, about 11, about 10, about 9 or about 8. In addition, the combination of a HEUR polymer with an amphiphilic polymer modulator gives the ink a drying rate on the print substrate that is acceptable, and provides good drop formation when ink jet printed and shows good printability.

[0040] Inks of the present invention, comprising a HEUR polymer and an amphiphilic polymer suitably have a viscosity that is stable over time. For example, the viscosity suitably changes by less than about 0.5 mPas, less than about 1 mPas, less than about 1.5 mPas or less than about 2 mPas after storage of the ink at 23⁰C for three months. Suitably, the colorant in the ink stays dispersed in the inks and does not agglomerate over time. For example, the mean particle size of the dispersed colorant may change by less than about 10 nm, less than about 15 nm, less than about 20 nm, less than about 30 nm, or less than about 40 nm after storage of the ink at 23⁰C for three months.

[0041] The ink compositions of the present invention may be formulated using a variety of methods known in the art. In one embodiment, a mill base is first prepared. The mill base may be a water-based concentrate containing about 5% to about 50% (by weight) of the dye or pigment. The mill base may include additives such as a defoamer (for example, AGIT AN®, commercially available from Mϋnzig Chemie, Germany) and a biocide (for example, PREVENTOL®, commercially available from Lanxess, Germany). Suitably a surfactant may be used in the mill base to wet the colorant and to stabilize, reduce or prevent agglomeration of the colorant particles.

[0042] Suitable surfactants for use in the mill base include, without limitation, lignosulfonate, alkylbenzene sulfonate, an alkylphenyl sulfonate, an alkylnaphthalene sulfonate, a higher fatty acid salt, a sulfate ester of a higher fatty acid ester, a sulfonate of a higher fatty acid ester, a sulfate ester and a sulfonate of a higher alcohol ether, a higher alkylsulfosuccinate, a polyoxyethylene alkylether carboxylate, a polyoxyethylene alkylether sulfate, an alkylphosphate, and a polyoxyethylene alkylether phosphate. Specific examples of the anionic surfactant include dodecylbenzene sulfonate, isopropylnaphthalene sulfonate, monobutylphenylphenol sulfonate, monobutylbiphenyl sulfonate, monobutylbiphenyl sulfonate, dibutylphenylphenol disulfonate, a polyoxyethylene alkyl ether, a polyoxyethylene alkyl phenyl ether, a polyoxyethylene fatty acid ester, a sorbitan fatty acid ester, a polyoxyethylene sorbitan fatty acid ester, a polyoxyethylene sorbitol fatty acid ester, a glycerin fatty acid ester, a polyoxyethylene glycerin fatty acid ester, a polyglycerin fatty acid ester, a cane sugar fatty acid ester, a polyoxyethylene alkylamine, a polyoxyethylene fatty acid amide, an alkylalkanolamide, a polyethylene glycol polypropylene glycol block copolymer, acetylene glycol, and a polyoxyethylene adduct of acetylene glycol, and specific examples of the nonionic surfactant include polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, a polyoxyethylene alkyl ether, a polyoxyethylene fatty acid ester, a sorbitan fatty acid ester, a polyoxyethylene sorbitan fatty acid ester, fatty acid alkylolamide, a polyethylene glycol/polypropylene glycol block copolymer, acetylene glycol, a polyoxyethylene adduct of acetylene glycol, inorganic or organic acid salts of an aliphatic primary amine such as octylamine, laurylamine, stearylamine, oleylamine, tetradecylamine, hexadecylamine, coconut amine, coconut alkylamine, tallow amine, cured tallow alkylamine, soybean alkylamine and the like; inorganic or organic acid salts of an aliphatic secondary amine such as distearylamine, dioleylamine, di-coconut alkylamine, di-cured tallow alkylamine and the like; inorganic or organic acid salts of aliphatic tertiary amine such as dimethyloctylamine, dimethyldecylamine, dimethylaurylamine, dimethylmyristylamine, dimethylpalmitylamine, dimethylstearylamine, dilaurylmonomethylamine, dioleylmonomethylamine, trioctyl amine, dimethyl coconut amine, coconut alkyldimethylamine, tallow alkyldimethylamine, cured tallow alkyldimethylamine, soybean alkyldimethylamine, di- coconut alkylmonomethylamine, di-cured tallow alkylmonomethylamine and the like; aliphatic quaternary ammonium salts such as tetramethylammonium chloride, tetraethylammonium chloride, tetrapropylammonium chloride, tetrabutylammonium chloride, lauryltrimethylammonium chloride, trioctylmethylammonium chloride, 3-chloro-2- hydroxypropyltrimethylammonium chloride, docosenyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, octadecyltrimethylammonium chloride, coconut alkytrimethylammonium chloride, tallow alkyltrimethylammonium chloride, octadecyldimethyl (3-trimethoxysilylpropyl)ammonium chloride and the like; aromatic quaternary ammonium salts such as benzyltrimethylammonium chloride, benzyltriethylammonium chloride, benzyltributylammonium chloride, benzyltrimethylammonium chloride, phenyltrimethylammonium chloride, cetyldimethylbenzylammonium chloride and the like; pyridinium salt type compounds (e.g., octylpyridinium chloride, cetylpicolinium chloride), imidazoline type cationic compounds (e.g., 2-heptadecenyl-hydroxyethylimidazolium chloride), benzotonium chloride, ethylene oxide added type quaternary ammonium salts (e.g., polyoxyethylenetrimethylammonium chloride), hydrochloride or acetate of aliphatic amides; salt of polyethylenepolyamine aliphatic amides; salt of urea condensate of polyethylenepolyamine aliphatic amides; quaternary ammonium salt of urea condensate of polyethylenepolyamine aliphatic amides; and N,N-dialkylmorphonium salts; and the like.

[0043] The mill base may be prepared using a conventional bead-mill. Alternatively, any other suitable attrition method may be used. The colorant is milled to an average primary particle size of about 70 to about 400 nm.

[0044] In one embodiment, the ink may be formulated by dilution of a mill base with water, a water miscible organic solvent, a HEUR polymer, an amphiphilic polymer and other optional suitable additives. In a suitable embodiment, the same water miscible organic solvent is used in the mill base and in the ink. The mixing of water, the water miscible organic solvent, the viscosity modifier, the modulator and any suitable additives is suitably carried out using an industrial mixer using processes known in the art. A bead mill or a rotor-stator type of mixer can be used for the mixing of the ingredients and the mill base. The ink is suitably thereafter micro- filtered through a filter cartridges or/and membranes, such as through a 0.25 μm nominal filter. [0045] In another embodiment, the ink may be prepared by adding a sufficient amount of a viscosity modifier such as a hydrophobically modified polyurethane thickening agent to the ink composition to increase the viscosity by at least about 5%, at least about 10%, at least about 20% or at least about 25% to obtain a higher viscosity ink suitable for applying to a textile. The step of adding the viscosity modifier may be repeated until the viscosity of the ink is from about 8 mPas to about 16 mPas. Then a sufficient amount of modulator may be added to decrease the solubility differences between the organic solvent and the hydrophobic segments of the viscosity modifier.

[0046] The ink compositions of the present invention are particularly suited for use as an ink composition for inkjet printing wherein droplets of the ink composition are ejected from a printing apparatus and deposited onto a substrate to generate an image. Suitable printing apparatus include, but are not limited to, industrial printers. As used herein, the term "industrial printers" refers to printers using heavy duty printheads and able to print more than 20 square meters per hour. Suitable printing apparatus include, but are not limited to, Continuous Ink Jet (CIJ), Drop-on-Demand Valve (DoD Valve), Drop-on-Demand Piezo-Electric (DoD Piezo), Memjet and Thermal Ink Jet (TIJ). Similarly, any suitable substrate may be employed including plain papers, bonded papers, coated papers, transparency materials, textile materials, plastics, polymeric films and inorganic substrates. In one embodiment, the ink compositions of the present invention may be particularly suited for printing on textile materials. However, it should be recognized by those skilled in the art that the above ink compositions may also have use in other applications including, but not limited to, general writing utensil applications and stamp applications.

[0047] The ink compositions of the present invention may be used alone, or with a color underlay, to produce a black image or in combination with other ink compositions to produce a color image. In some embodiments, the ink composition of the present invention is used in combination with other ink composition(s), such as a black ink, a cyan ink, a magenta ink and/or a yellow ink. In other embodiments, a cyan ink, a magenta ink and a yellow ink are overprinted to form a black image and this printing may be used in combination with the printing of a black ink of the present invention. Suitably, when inks of the present invention are printed, the droplets of jetted ink provide images that are regular, have a good resolution, and resist bleeding and smearing.

[0048] The following examples are illustrative and are not to be construed as limiting the scope of the invention.

EXAMPLES

Example 1

[0049] An ink was formulated as set forth in Table 1. A mill base was made by milling each of the mill base components of Table 1 using a horizontal bead mill (Dyno-Mill, commercially available from Willy A, Bachofen AG Maschinenfabrik, Switzerland) until the mean particle size measured by photon correlation spectroscopy was below 150 nm. The ink was made by blending the ink ingredients of Table 1 using an industrial mixer. The precise amounts of the HEUR polymer and amphiphilic polymer were added to adjust the viscosity of the ink to the desired level. The viscosity of the ink was measured using a cone-plate rheometer (commercially available from Haake Rheostress 1, Thermo Scientific, USA). The final viscosity of the ink was about 14 mPas at 23°C. The pH of the ink was between 6.9 to 7.5 at 23°C.

Table 1.

[0050] The viscosity of a batch of the ink at different pH values is shown in Table 2.

Table 2.

[0051] The ink was printed using a DOD print head at 18 kHz. 1 kg of ink was printed without the nozzle clogging. The droplet velocity deviation was less than 6%, and the drop angle deviation was less than 0.5°. An image of the droplets formed is shown in Figure 1. The droplets formed were regular, showed a good drying time with good printability.

Example 2

[0052] An ink was formulated as set forth in Table 3. A mill base was made by milling each of the mill base components of Table 3 using a horizontal bead mill (Dyno-Mill, commercially available from Willy A, Bachofen AG Maschinenfabrik, Switzerland) until the mean particle size measured by photon correlation spectroscopy was below 150 nm. The ink was made by blending the ink ingredients of Table 3 using an industrial mixer. The precise amounts of the HEUR polymer and amphiphilic polymer are added to adjust the viscosity of the ink to the desired level. The viscosity of the ink was measured using a cone-plate rheometer (commercially available from Haake Rheostress 1, Thermo Scientific, USA). The viscosity of the ink was 13.5 mPas at 23°C. The pH of the ink was between 5.9 to 6.2 at 23⁰C.

[0053]

Table 3.

[0054] The ink was printed using a DOD print head at 17 kHz. 1 kg of ink was printed without the nozzle clogging. The droplet velocity deviation was less than 5%, and the drop angle deviation was less than 0.5°. An image of the droplets formed is shown in Figure 2. The droplets formed were regular, showed a good drying time with good printability.

Example 3

[0055] An ink was formulated as set forth in Table 4. A mill base was made by milling each of the mill base components of Table 4 using a horizontal bead mill (Dyno-Mill, commercially available from Willy A, Bachofen AG Maschinenfabrik, Switzerland) until the mean particle size measured by photon correlation spectroscopy was below 150 nm. The ink was made by blending the ink ingredients of Table 4 using an industrial mixer. The precise amounts of the HEUR polymer and amphiphilic polymer were added to adjust the viscosity of the ink to the desired level. The viscosity of the ink was measured using a cone-plate rheometer (commercially available from Haake Rheostress 1, Thermo Scientific, USA). The viscosity of the ink was 14 mPas at 23°C. The pH of the ink was between 5.7 to 6.5 at 23°C.

Table 4.

[0056] The ink was printed using a DOD print head at 18 kHz. 1 kg of ink was printed without the nozzle clogging. The droplet velocity deviation was less than 6%, and the drop angle deviation was less than 0.5°. An image of the droplets formed is shown in Figure 3. The droplets formed were regular, showed a good drying time with good printability.

Example 4

[0057] An ink is formulated as set forth in Table 5. A mill base is made by milling each of the mill base components of Table 5 using a horizontal bead mill (Dyno-Mill, commercially available from Willy A, Bachofen AG Maschinenfabrik, Switzerland) until the mean particle size measured by photon correlation spectroscopy is below 150 nm. The ink is made by blending the ink ingredients of Table 5 using an industrial mixer. The precise amounts of the HEUR polymer and amphiphilic polymer are added to adjust the viscosity of the ink to the desired level. The viscosity of the ink is measured using a cone-plate rheometer (commercially available from Haake Rheostress 1, Thermo Scientific, USA). The viscosity of the ink is expected to be 12.6 mPas at 23°C. The pH of the ink is expected to be between 6.9 to 7.5 at 23°C.

Table 5.

[0058] The viscosity of the ink at different pH values is shown in Table 6.

Table 6.

[0059] The ink is printed using a DOD print head at 25 ⁰C, 103 V, and 19 kHz. A regular droplet formation is expected when the ink is printed. This ink is expected to print at least one kilogram through one printhead without any clogging of the nozzle. The microscopic droplets formed are expected to be regular, have a good drying time and show good printability.

Comparative Example 5

[0060] An ink is formulated as set forth in Table 7. The mill base is made using the mill base components listed in Table 4 and milled using a horizontal bead mill (Dyno-Mill, commercially available from Willy A, Bachofen AG Maschinenfabrik, Switzerland) until the mean particle size measured by photon correlation spectroscopy is below 150 nm. The ink is made by blending the ingredients of Table 7 using an industrial mixer. The precise amount of the HEUR polymer is added to adjust the viscosity of the ink to the desired level. The viscosity of the ink is measured using a cone-plate rheometer (commercially available from Haake Rheostress 1 , Thermo Scientific, USA). The viscosity of the ink is expected to be 12 mPas at 23°C. The pH of the ink is expected to be between 6.9 to 7.5 at 23⁰C.

Table 7.

[0061] The ink is printed using a DOD print head at 25 ⁰C, 103 V, and 19 kHz. An irregular droplet formation is expected when the ink is printed. This ink is expected to print less than 100 g through one printhead before clogging of the nozzle occurs. The microscopic droplets formed are expected to be irregular and smeared.

Comparative Example 6

[0062] An ink is formulated as set forth in Table 8. The mill base is made using the mill base components listed in Table 4 and milled using a horizontal bead mill (Dyno-Mill, commercially available from Willy A, Bachofen AG Maschinenfabrik, Switzerland) until the mean particle size measured by photon correlation spectroscopy is below 150 nm. The ink is made by blending the ingredients of Table 8 using an industrial mixer. The viscosity of the ink is measured using a cone-plate rheometer (commercially available from Haake Rheostress 1, Thermo Scientific, USA). The viscosity of the ink is expected to be 14 mPas at 23⁰C. The pH of the ink is expected to be between 6.9 to 7.5 at 23°C. .

Table 8.

[0063] The ink is printed using a DOD print head at 25 ⁰C, 103 V, and 19 kHz. An irregular droplet formation is expected when the ink is printed. This ink is expected to print less than 1O g through one printhead before clogging of the nozzle occurs. The microscopic droplets formed are expected to be irregular and smeared.

Example 7 [0064] An ink is formulated as set forth in Table 9. A mill base is made by milling each of the mill base components of Table 9 using a horizontal bead mill (Dyno-Mill, commercially available from Willy A, Bachofen AG Maschinenfabrik, Switzerland) until the mean particle size measured by photon correlation spectroscopy is below 150 nm. The ink is made by blending the ink ingredients of Table 9 using an industrial mixer. The precise amounts of the HEUR polymer and amphiphilic polymer are added to adjust the viscosity of the ink to the desired level. The viscosity of the ink is measured using a cone-plate rheometer (commercially available from Haake Rheostress 1, Thermo Scientific, USA). The viscosity of the ink is expected to be 12 mPas at 23°C. The pH of the ink is expected to be between 7.0 to 7.3 at 23°C.

Table 9.

[0065] The ink is printed using a DOD print head at 25 ⁰C, 103 V, and 19 kHz. A regular droplet formation is expected when the ink is printed. This ink is expected to print at least one kilogram through one printhead without any clogging of the nozzle. The microscopic droplets formed are expected to be regular, have a good drying time and show good printability.

Example 8

[0066] An ink was formulated as set forth in Table 10. A mill base was made by milling each of the mill base components of Table 10 using a horizontal bead mill (Dyno-Mill, commercially available from Willy A, Bachofen AG Maschinenfabrik, Switzerland) until the mean particle size measured by photon correlation spectroscopy was below 150 nm. The ink was made by blending the ink ingredients of Table 10 using an industrial mixer. The precise amounts of the HEUR polymer and amphiphilic polymer were added to adjust the viscosity of the ink to the desired level. The viscosity of the ink was measured using a cone-plate rheometer (commercially available from Haake Rheostress 1, Thermo Scientific, USA). The viscosity of the ink was 12 mPas at 23°C. The pH of the ink was between 7.0 to 7.3 at 23°C.

Table 10.

[0067] The ink was printed using a DOD print head. The droplets formed were regular, showed a good drying time with good printability.

Example 9

[0068] An ink was formulated as set forth in Table 11. A mill base was made by milling each of the mill base components of Table 11 using a horizontal bead mill (Dyno-Mill, commercially available from Willy A, Bachofen AG Maschinenfabrik, Switzerland) until the mean particle size measured by photon correlation spectroscopy was below 150 nm. The ink was made by blending the ink ingredients of Table 10 using an industrial mixer. The precise amounts of the HEUR polymer and amphiphilic polymer were added to adjust the viscosity of the ink to the desired level. The viscosity of the ink was measured using a cone-plate rheometer (commercially available from Haake Rheostress 1, Thermo Scientific, USA). The viscosity of the ink was 12.6 mPas at 23°C. The pH of the ink was between 6.9 to 7.5 at 23°C.

Table 11.

Mill base

Component Amount (wt %)

[0069] The ink was printed using a DOD print head. The droplets formed were regular, showed a good drying time with good printability.

[0070] All patents, publications and references cited herein are hereby fully incorporated by reference. In case of conflict between the present disclosure and incorporated patents, publications and references, the present disclosure should control. Various features and advantages of the invention are set forth in the following claims.

Claims

CLAIMSWhat is claimed is:

1. An ink jet ink for printing on a substrate, comprising: a colorant; a hydrophobic ethoxylated urethane polymer; and an amphiphilic polymer.

2. The ink of claim 1, wherein the ink comprises less than about 0.05 % by weight of a pH modifier.

3. The ink of claim 1, wherein the ink comprises less than about 0.05 % by weight of a pH buffer.

4. The ink of claim 1, further comprising water.

5. The ink of claim 4, further comprising a water-soluble organic solvent.

6. The ink of claim 1, wherein the ink has a viscosity of about 8 mPas to about 16 mPas at 23 ⁰C.

7. The ink of claim 6, wherein the viscosity is about 10 mPas to about 14 mPas at 23 ⁰C.

8. The ink of claim 7, wherein the viscosity changes by less than about 3 mPas when the pH of the ink is increased from about pH 5 to about pH 9.

9. The ink of claim 1, wherein the ink has a viscosity that changes by less than 3 mPas when the pH of the ink is increased from about pH 5 to about pH 9.

10. The ink of claim 1, wherein the hydrophobic ethoxylated urethane polymer is present at about 0.1 % to about 20% by weight of the ink.

11. The ink of claim 10, wherein the hydrophobic ethoxylated urethane polymer is present at about 0.5% to about 6% by weight of the ink.

12. The ink of claim 1, wherein the amphiphilic polymer is present at about 1% to about 20% by weight of the ink.

13. The ink of claim 12, wherein the amphiphilic polymer is present at about 8% to about 12% by weight of the ink.

14. The ink of claim 1, wherein the amphiphilic polymer comprises an amphiphilic long chain polymer, an amphiphilic block copolymer, an amphiphilic comb-like copolymer, an amphiphilic gradient copolymer, or a combination thereof.

15. The ink of claim 1, wherein the colorant comprises a disperse dye.

16. The ink of claim 1, wherein the colorant comprises a pigment.

17. The ink of claim 1, wherein the pH of the ink is less than about 10.

18. The ink of claim 17, wherein the pH of the ink is less than about 8.

19. A method of manufacturing an ink, the method comprising incorporating a hydrophobic ethoxylated urethane polymer and an amphiphilic polymer in the ink to provide an ink having a viscosity of about 10 mPas to about 14 mPas.

20. The method of claim 19, wherein the viscosity changes by less than about 3 mPas when the pH of the ink is increased from about pH 5 to about pH 9.

21. A method of printing on a substrate, the method comprising jetting an ink comprising a colorant, a hydrophobically modified polyurethane thickening agent, and an amphiphilic polymer on the substrate with an ink jet printer.

22. The method of claim 21, wherein the inkjet printer is a piezoelectric inkjet printer.

23. The method of claim 21, wherein the inkjet printer is an industrial inkjet printer.

24. The method of claim 21, wherein the substrate comprises a textile.

25. The method of claim 21, wherein the inkjet printer comprises a nozzle through which the ink exits the printer, and wherein the jetted ink has a velocity deviation of less than 7% after 4 x 10⁸ droplets have exited from the nozzle.

26. The method of claim 25, wherein the ink is jetted at an initial angle, and wherein the jetted ink has an angle deviation of no more than 0.5° from the initial angle after 4 x 10 droplets have exited from the nozzle.

27. The method of claim 21, wherein the inkjet printer comprises a nozzle through which the ink exits the printer, and wherein the nozzle substantially does not clog after 200 g of ink have exited the nozzle.