WO2022182360A1

WO2022182360A1 - Thermal inkjet ink composition and textile printing kit

Info

Publication number: WO2022182360A1
Application number: PCT/US2021/019916
Authority: WO
Inventors: Dennis Z. Guo; Jie Zheng
Original assignee: Hewlett-Packard Development Company, L.P.
Priority date: 2021-02-26
Filing date: 2021-02-26
Publication date: 2022-09-01

Abstract

A thermal inkjet ink composition includes a pigment, a polymeric binder, a blocked polyisocyanate crosslinker, and an aqueous ink vehicle. The polymeric binder is selected from the group consisting of polyurethane-based binder and an acrylic binder. The blocked polyisocyanate crosslinker includes a blocking group having an initial deblocking temperature of at least 150°C.

Description

THERMAL INKJET INK COMPOSITION AND TEXTILE PRINTING KIT

BACKGROUND

[0001] Textile printing methods often include rotary and/or flat-screen printing. Traditional analog printing typically involves the creation of a plate or a screen, i.e. , an actual physical image from which ink is transferred to the textile. Both rotary and flat screen printing have great volume throughput capacity, but also have limitations on the maximum image size that can be printed. For large images, pattern repeats are used. Conversely, digital inkjet printing enables greater flexibility in the printing process, where images of any desirable size can be printed immediately from an electronic image without pattern repeats. Inkjet printers are gaining acceptance for digital textile printing. Inkjet printing is a non-impact printing method that utilizes electronic signals to control and direct droplets or a stream of ink to be deposited on media.

BRIEF DESCRIPTION OF THE DRAWINGS [0002] Features of examples of the present disclosure will become apparent by reference to the following detailed description and drawings.

[0003] Fig. 1 is a schematic illustration of an example inkjet ink and an example textile printing kit;

[0004] Fig. 2 is a flow diagram illustrating an example printing method;

[0005] Fig. 3 is a schematic diagram of an example of a printing system and different examples of the printing method; [0006] Fig. 4A depicts Turn-On-Energy (TOE) curves for four example black inks, a control black ink, and two comparative example black inks, plotting drop weight in nanograms (ng) vs. firing energy in microJoules (pJ);

[0007] Fig. 4B depicts Turn-On-Energy (TOE) curves for three example cyan inks, a control cyan ink, and two comparative example cyan inks, plotting drop weight in nanograms (ng) vs. firing energy in microJoules (pJ);

[0008] Fig. 5A depicts the frequency response of the four example black inks, the control black ink, and the two comparative example black inks, plotting drop weight in nanograms (ng) vs. frequency in kiloHertz (kFIz); and

[0009] Fig. 5B depicts the frequency response of the three example cyan inks, the control cyan ink, and the two comparative example cyan inks, plotting drop weight in nanograms (ng) vs. frequency in kiloHertz (kFIz).

DETAILED DESCRIPTION

[0010] The textile market is a major industry, and printing on textiles, such as cotton, polyester, etc., has been evolving to include digital printing methods. However, the vast majority of textile printing (> 95%) is still performed by analog methods, such as screen printing. Multi-color printing with analog screen printing involves the use of a separate screen for each color that is to be included in the print, and each color is applied separately (with its corresponding screen). In contrast, digital inkjet printing can generate many colors by mixing basic colors in desired locations on the textile, and thus avoids the limitations of analog screen printing.

[0011] Disclosed herein is a thermal inkjet ink (i.e. , thermal inkjet ink composition, inkjet ink, etc.) that is suitable for being printed on a variety of textile fabrics, including cotton, polyester, polyester and cotton blends, nylon, and silk. The thermal inkjet ink includes a blocked polyisocyanate which includes a blocking group having an initial deblocking temperature of at least 150°C. Deblocking, i.e., removal of the blocking groups, can occur over a range of temperatures for a period of time (e.g., several minutes), and the “initial deblocking temperature” refers to the temperature at which deblocking is first observed. The initial deblocking temperature can be detected using a variety of techniques. As one example, the initial deblocking temperature may be determined using Fourier-transform infrared spectroscopy (FTIR) and corresponds with the initial detection of an isocyanate (NCO) peak. As another example, the initial deblocking temperature may be determined using Differential scanning calorimetry (DSC) and corresponds with a temperature where sudden heat flow increases. As still another example, the initial deblocking temperature may be determined using Thermogravimetric analysis (TGA) and corresponds with a temperature where a sudden change (decrease) in sample weight occurs.

[0012] The relatively high initial deblocking temperature helps to stabilize the blocked polyisocyanate during thermal inkjet printing firing conditions, which improves the jettability and useful life of the inkjet ink. During thermal inkjet printing firing, a thermal inkjet ink may be heated to temperatures up to 300°C for a few microseconds. The stability may result from the fact that the thermal inkjet printing firing conditions do not enable the deblocking reactions, and thus the isocyanate groups are not available in the print cartridge for crosslinking or other reactions. For example, while the temperature may be high enough to initiate deblocking, the exposure of the ink to the temperature is so short that deblocking is either not initiated or is minimal. The short duration of the firing event does not allow the deblocking reaction to reach the activation energy required to drive the deblocking reaction forward, thus not enabling deblocking to take place in the thermal inkjet printhead. By not initiating deblocking within the thermal inkjet applicator (which includes a thermal inkjet printhead), the reliability of the applicator is improved.

[0013] The thermal inkjet ink disclosed herein may also generate prints having desirable washfastness, even when the thermal inkjet ink is printed without a fixer fluid. More particularly, the blocked polyisocyanate in the inkjet ink is deblocked during the curing portion of the printing process, and thus is available for crosslinking. The deblocked isocyanate groups can crosslink with the functional groups in the polyurethane- or acrylic-based binder in the inkjet ink, and/or crosslink with the functional groups on the textile fabric substrate. While prints with desirable washfastness are achieved when the thermal inkjet ink is printed alone, it is believed that the optical density of the print may be improved when the thermal inkjet ink is printed with a fixer fluid containing a multivalent metal salt. The multivalent metal salt can interact with pigment in the ink directly on the textile fabric, which can fix the pigment and improve the optical density.

[0014] Washfastness is the ability of a textile fabric to retain color after being exposed to washing. Washfastness is an indication of the print’s durability. Washfastness can be measured in terms of a change in L* before and after washing.

L* is measured in the CIELAB color space, and may be measured using any suitable color measurement instrument (such as those available from HunterLab orX-Rite). [0015] The inkjet ink disclosed herein may include different components with different acid numbers. As used herein, the term “acid number” refers to the mass of potassium hydroxide (KOH) in milligrams that is used to neutralize one (1) gram of a particular substance. The test for determining the acid number of a particular substance may vary, depending on the substance. For example, to determine the acid number of a polyurethane-based binder, a known amount of a sample of the binder may be dispersed in water and the aqueous dispersion may be titrated with a polyelectrolyte titrant of a known concentration. In this example, a current detector for colloidal charge measurement may be used. An example of a current detector is the Miitek PCD-05 Smart Particle Charge Detector (available from BTG). The current detector measures colloidal substances in an aqueous sample by detecting the streaming potential as the sample is titrated with the polyelectrolyte titrant to the point of zero charge. An example of a suitable polyelectrolyte titrant is poly(diallyldimethylammonium chloride) (i.e. , PolyDADMAC). It is to be understood that any suitable test for a particular component may be used.

[0016] Throughout this disclosure, a weight percentage that is referred to as “wt% active” refers to the loading of an active component of a dispersion or other formulation that is present in the fixer fluid or the inkjet ink. For example, a pigment may be present in a water-based formulation (e.g., a stock solution or dispersion) before being incorporated into the inkjet ink. In this example, the wt% actives of the pigment accounts for the loading (as a weight percent) of the pigment that is present in the inkjet ink, and does not account for the weight of the other components (e.g., water, etc.) that are present in the formulation with the pigment. The term “wt%,” without the term actives, refers to the loading (in the fixer fluid or the inkjet ink) of a 100% active component that does not include other non-active components therein. [0017] The term “molecular weight” as used herein refers to weight average molecular weight (Mw), the units of which are g/mol or Daltons.

[0018] The viscosity measurements set forth herein represent those measured by a viscometer at a particular temperature and at a particular shear rate (s ¹) or at a particular speed. The temperature and shear rate or temperature and speed are identified with individual values. Viscosity may be measured, for example, by a VISCOLITE™ viscometer (from Hydramotion) or another suitable instrument.

[0019] Thermal Inkjet Ink

[0020] An example of the thermal inkjet ink disclosed herein includes a pigment; a polymeric binder selected from the group consisting of polyurethane-based binder and an acrylic binder; a blocked polyisocyanate crosslinker including a blocking group having an initial deblocking temperature of at least 150°C; and an aqueous ink vehicle. [0021 ] Another example of the thermal inkjet ink disclosed herein includes a pigment; a polymeric binder selected from the group consisting of polyurethane-based binder and an acrylic binder; an aliphatic blocked polyisocyanate crosslinker, wherein a polyisocyanate of the aliphatic blocked polyisocyanate crosslinker is selected from the group consisting of 4,4'-dicyclohexylmethane diisocyanate, hexamethylene diisocyanate trimer, hexamethylene diisocyanate biuret, isophorone diisocyanate, and isophorone diisocyanate trimer, and a blocking group of the aliphatic blocked polyisocyanate crosslinker is selected from the group consisting of e-caprolactam, ethanol, isopropanol, butanol, phenol, o-Cresol, benzophenone oxime, imidazole, 2- methylimidazole, 2-phenylimidazole, benzotriazole, uretdione, and 2-oxo-1,3- diazepane-1-carboxylate; and an aqueous ink vehicle including an anti-kogation agent. [0022] Pigment

[0023] The pigment may be incorporated into the ink composition as a pigment dispersion. The pigment dispersion may include a pigment and a separate dispersant, or may include a self-dispersed pigment. Whether separately dispersed or self- dispersed, the pigment can be any of a number of primary or secondary colors, or black or white. As specific examples, the pigment may be any color, including, as examples, a cyan pigment, a magenta pigment, a yellow pigment, a black pigment, a violet pigment, a green pigment, a brown pigment, an orange pigment, a purple pigment, a white pigment, or combinations thereof.

[0024] Pigments and separate dispersants

[0025] Examples of the thermal inkjet ink may include a pigment that is not self- dispersing and a separate dispersant. Examples of these pigments, as well as suitable dispersants for these pigments will now be described.

[0026] Examples of suitable blue or cyan organic pigments include C.l. Pigment Blue 1 , C.l. Pigment Blue 2, C.l. Pigment Blue 3, C.l. Pigment Blue 15, Pigment Blue 15:3, C.l. Pigment Blue 15:4, C.l. Pigment Blue 16, C.l. Pigment Blue 18, C.l. Pigment Blue 22, C.l. Pigment Blue 25, C.l. Pigment Blue 60, C.l. Pigment Blue 65, C.l.

Pigment Blue 66, C.l. Vat Blue 4, and C.l. Vat Blue 60.

[0027] Examples of suitable magenta, red, or violet organic pigments include C.l. Pigment Red 1, C.l. Pigment Red 2, C.l. Pigment Red 3, C.l. Pigment Red 4, C.l. Pigment Red 5, C.l. Pigment Red 6, C.l. Pigment Red 7, C.l. Pigment Red 8, C.l. Pigment Red 9, C.l. Pigment Red 10, C.l. Pigment Red 11, C.l. Pigment Red 12, C.l. Pigment Red 14, C.l. Pigment Red 15, C.l. Pigment Red 16, C.l. Pigment Red 17, C.l.

Pigment Red 18, C.l. Pigment Red 19, C.l. Pigment Red 21, C.l. Pigment Red 22, C.l.

Pigment Red 23, C.l. Pigment Red 30, C.l. Pigment Red 31, C.l. Pigment Red 32, C.l.

Pigment Red 37, C.l. Pigment Red 38, C.l. Pigment Red 40, C.l. Pigment Red 41, C.l.

Pigment Red 42, C.l. Pigment Red 48(Ca), C.l. Pigment Red 48(Mn), C.l. Pigment Red 57(Ca), C.l. Pigment Red 57:1 , C.l. Pigment Red 88, C.l. Pigment Red 112, C.l. Pigment Red 114, C.l. Pigment Red 122, C.l. Pigment Red 123, C.l. Pigment Red 144, C.l. Pigment Red 146, C.l. Pigment Red 149, C.l. Pigment Red 150, C.l. Pigment Red 166, C.l. Pigment Red 168, C.l. Pigment Red 170, C.l. Pigment Red 171, C.l. Pigment Red 175, C.l. Pigment Red 176, C.l. Pigment Red 177, C.l. Pigment Red 178, C.l. Pigment Red 179, C.l. Pigment Red 184, C.l. Pigment Red 185, C.l. Pigment Red 187, C.l. Pigment Red 202, C.l. Pigment Red 209, C.l. Pigment Red 219, C.l. Pigment Red 224, C.l. Pigment Red 245, C.l. Pigment Red 286, C.l. Pigment Violet 19, C.l. Pigment Violet 23, C.l. Pigment Violet 32, C.l. Pigment Violet 33, C.l. Pigment Violet 36, C.l. Pigment Violet 38, C.l. Pigment Violet 43, and C.l. Pigment Violet 50. Any quinacridone pigment or a co-crystal of quinacridone pigments may be used for magenta inks.

[0028] Examples of suitable yellow organic pigments include C.l. Pigment Yellow 1 , C.l. Pigment Yellow 2, C.l. Pigment Yellow 3, C.l. Pigment Yellow 4, C.l. Pigment Yellow 5, C.l. Pigment Yellow 6, C.l. Pigment Yellow 7, C.l. Pigment Yellow 10, C.l. Pigment Yellow 11, C.l. Pigment Yellow 12, C.l. Pigment Yellow 13, C.l. Pigment Yellow 14, C.l. Pigment Yellow 16, C.l. Pigment Yellow 17, C.l. Pigment Yellow 24,

C.l. Pigment Yellow 34, C.l. Pigment Yellow 35, C.l. Pigment Yellow 37, C.l. Pigment Yellow 53, C.l. Pigment Yellow 55, C.l. Pigment Yellow 65, C.l. Pigment Yellow 73,

C.l. Pigment Yellow 74, C.l. Pigment Yellow 75, C.l. Pigment Yellow 77, C.l. Pigment Yellow 81, C.l. Pigment Yellow 83, C.l. Pigment Yellow 93, C.l. Pigment Yellow 94,

C.l. Pigment Yellow 95, C.l. Pigment Yellow 97, C.l. Pigment Yellow 98, C.l. Pigment Yellow 99, C.l. Pigment Yellow 108, C.l. Pigment Yellow 109, C.l. Pigment Yellow 110, C.l. Pigment Yellow 113, C.l. Pigment Yellow 114, C.l. Pigment Yellow 117, C.l. Pigment Yellow 120, C.l. Pigment Yellow 122, C.l. Pigment Yellow 124, C.l. Pigment Yellow 128, C.l. Pigment Yellow 129, C.l. Pigment Yellow 133, C.l. Pigment Yellow 138, C.l. Pigment Yellow 139, C.l. Pigment Yellow 147, C.l. Pigment Yellow 151, C.l. Pigment Yellow 153, C.l. Pigment Yellow 154, C.l. Pigment Yellow 155, C.l. Pigment Yellow 167, C.l. Pigment Yellow 172, C.l. Pigment Yellow 180, C.l. Pigment Yellow 185, and C.l. Pigment Yellow 213.

[0029] Carbon black may be a suitable inorganic black pigment. Examples of carbon black pigments include those manufactured by Mitsubishi Chemical Corporation (such as, e.g., carbon black No. 2300, No. 900, MCF88, No. 33, No. 40, No. 45, No. 52, MA7, MA8, MA100, and No. 2200B); various carbon black pigments of the RAVEN^® series manufactured by Columbian Chemicals Company (such as, e.g., RAVEN^® 5750, RAVEN^® 5250, RAVEN^® 5000, RAVEN^® 3500, RAVEN^® 1255, and RAVEN^® 700); various carbon black pigments of the REGAL^® series, BLACK PEARLS^® series, the MOGUL^® series, or the MONARCH^® series manufactured by Cabot Corporation (such as, e.g., REGAL^® 400R, REGAL^® 330R, REGAL^® 660R, BLACK PEARLS^® 700, BLACK PEARLS^® 800, BLACK PEARLS^® 880, BLACK PEARLS^® 1100, BLACK PEARLS^® 4350, BLACK PEARLS^® 4750, MOGUL^® E, MOGUL^® L, and ELFTEX^® 410); and various black pigments manufactured by Orion Engineered Carbons (such as, e.g., Color Black FW1 , Color Black FW2, Color Black FW2V, Color Black FW18, Color Black FW200, Color Black S150, Color Black S160, Color Black S170, PRINTEX^® 35, PRINTEX^® 75, PRINTEX^® 80, PRINTEX^® 85, PRINTEX^® 90, PRINTEX^® U, PRINTEX^® V, PRINTEX^® 140U, Special Black 5, Special Black 4A, and Special Black 4). An example of an organic black pigment includes aniline black, such as C.l. Pigment Black 1.

[0030] Some examples of green organic pigments include C.l. Pigment Green 1 ,

C.l. Pigment Green 2, C.l. Pigment Green 4, C.l. Pigment Green 7, C.l. Pigment Green 8, C.l. Pigment Green 10, C.l. Pigment Green 36, and C.l. Pigment Green 45. [0031 ] Examples of brown organic pigments include C.l. Pigment Brown 1 , C.l. Pigment Brown 5, C.l. Pigment Brown 22, C.l. Pigment Brown 23, C.l. Pigment Brown 25, C.l. Pigment Brown 41 , and C.l. Pigment Brown 42.

[0032] Some examples of orange organic pigments include C.l. Pigment Orange 1 , C.l. Pigment Orange 2, C.l. Pigment Orange 5, C.l. Pigment Orange 7, C.l. Pigment Orange 13, C.l. Pigment Orange 15, C.l. Pigment Orange 16, C.l. Pigment Orange 17, C.l. Pigment Orange 19, C.l. Pigment Orange 24, C.l. Pigment Orange 34, C.l.

Pigment Orange 36, C.l. Pigment Orange 38, C.l. Pigment Orange 40, C.l. Pigment Orange 43, C.l. Pigment Orange 64, C.l. Pigment Orange 66, C.l. Pigment Orange 71 , and C.l. Pigment Orange 73.

[0033] The average particle size of the pigments may range anywhere from about 20 nm to about 200 nm. In an example, the average particle size ranges from about 80 nm to about 150 nm. As used herein, the “average particle size” refers to a volume-weighted mean diameter of a particle size distribution.

[0034] Any of the pigments mentioned herein can be dispersed by a separate dispersant, such as a styrene (meth)acrylate dispersant, or another dispersant suitable for keeping the pigment suspended in the aqueous ink vehicle. For example, the dispersant can be any dispersing (meth)acrylate polymer, or other type of polymer, such as a maleic polymer or a dispersant with aromatic groups and a poly(ethylene oxide) chain. [0035] In one example, the (meth)acrylate polymer dispersant can be a styrene- acrylic type dispersant polymer, as it can promote tt-stacking between the aromatic ring of the dispersant and various types of pigments, such as copper phthalocyanine pigments, for example. In one example, the styrene-acrylic dispersant can have a weight average molecular weight (M_w) ranging from about 4,000 to about 30,000. In another example, the styrene-acrylic dispersant can have a weight average molecular weight ranging from about 8,000 to about 28,000, from about 12,000 to about 25,000, from about 15,000 to about 25,000, from about 15,000 to about 20,000, or about 17,000. Regarding the acid number, the styrene-acrylic dispersant can have an acid number from 100 to 350, from 120 to 350, from 150 to 250, from 155 to 185, or about 172, for example. Example commercially available styrene-acrylic dispersants can include JONCRYL® 671 , JONCRYL® 71 , JONCRYL® 96, JONCRYL® 680, JONCRYL® 683, JONCRYL® 678, JONCRYL® 690, JONCRYL® 296, JONCRYL® 696 or JONCRYL® ECO 675 (all available from BASF Corp.).

[0036] The term “(meth)acrylate” or “(meth)acrylic acid” or the like refers to monomers, copolymerized monomers, etc., that can either be acrylate or methacrylate (or a combination of both), or acrylic acid or methacrylic acid (or a combination of both). Also, in some examples, the terms “(meth)acrylate” and “(meth)acrylic acid” can be used interchangeably, as acrylates and methacrylates are salts and esters of acrylic acid and methacrylic acid, respectively. Furthermore, mention of one compound over another can be a function of pH. For example, even if the monomer used to form the polymer was in the form of a (meth)acrylic acid during preparation, pH modifications during preparation or subsequently when added to the ink composition can impact the nature of the moiety (acid form vs. salt or ester form).

Thus, a monomer or a moiety of a polymer described as (meth)acrylic acid or as (meth)acrylate should not be read so rigidly as to not consider relative pH levels, ester chemistry, and other general organic chemistry concepts.

[0037] The following are some example pigment and separate dispersant combinations: a carbon black pigment with a styrene acrylic dispersant; PB 15:3 (cyan pigment) with a styrene acrylic dispersant; PR122 (magenta) or a co-crystal of PR122 and PV19 (magenta) with a styrene acrylic dispersant; or PY74 (yellow) or PY155 (yellow) with a styrene acrylic dispersant.

[0038] In an example, the pigment is present in the thermal inkjet ink in an amount ranging from about 1 wt% active to about 6 wt% active of the total weight of the thermal inkjet ink. In another example, the pigment is present in the ink composition in an amount ranging from about 2 wt% active to about 6 wt% active of the total weight of the thermal inkjet ink. When the separate dispersant is used, the separate dispersant may be present in an amount ranging from about 0.05 wt% active to about 6 wt% active of the total weight of the thermal inkjet ink. In some examples, the ratio of pigment to separate dispersant may range from 0.1 (1 : 10) to 1 (1:1).

[0039] Self-dispersed pigments

[0040] In other examples, the thermal inkjet ink includes a self-dispersed pigment, which includes a pigment and an organic group attached thereto.

[0041 ] Any of the pigments set forth herein may be used, such as carbon, phthalocyanine, quinacridone, azo, or any other type of organic pigment, as long as at least one organic group that is capable of dispersing the pigment is attached to the pigment.

[0042] The organic group that is attached to the pigment includes at least one aromatic group, an alkyl (e.g., Ci to C20), and an ionic or ionizable group.

[0043] The aromatic group may be an unsaturated cyclic hydrocarbon containing one or more rings and may be substituted or unsubstituted, for example with alkyl groups. Aromatic groups include aryl groups (for example, phenyl, naphthyl, anthracenyl, and the like) and heteroaryl groups (for example, imidazolyl, pyrazolyl, pyridinyl, thienyl, thiazolyl, furyl, triazinyl, indolyl, and the like).

[0044] The alkyl may be branched or unbranched, substituted or unsubstituted. [0045] The ionic or ionizable group may be at least one phosphorus-containing group, at least one sulfur-containing group, or at least one carboxylic acid group.

[0046] In an example, the at least one phosphorus-containing group has at least one P—O bond or P=0 bond, such as at least one phosphonic acid group, at least one phosphinic acid group, at least one phosphinous acid group, at least one phosphite group, at least one phosphate, diphosphate, triphosphate, or pyrophosphate groups, partial esters thereof, or salts thereof. By "partial ester thereof”, it is meant that the phosphorus-containing group may be a partial phosphonic acid ester group having the formula — P0₃RH, or a salt thereof, wherein R is an aryl, alkaryl, aralkyl, or alkyl group. By "salts thereof”, it is meant that the phosphorus-containing group may be in a partially or fully ionized form having a cationic counterion.

[0047] When the organic group includes at least two phosphonic acid groups or salts thereof, either or both of the phosphonic acid groups may be a partial phosphonic ester group. Also, one of the phosphonic acid groups may be a phosphonic acid ester having the formula — PO3R2, while the other phosphonic acid group may be a partial phosphonic ester group, a phosphonic acid group, or a salt thereof. In some instances, it may be desirable that at least one of the phosphonic acid groups is either a phosphonic acid, a partial ester thereof, or salts thereof. When the organic group includes at least two phosphonic acid groups, either or both of the phosphonic acid groups may be in either a partially or fully ionized form. In these examples, either or both may of the phosphonic acid groups have the formula — PO3H2, — PO3H M⁺ (monobasic salt), or — P0₃ ² M⁺² (dibasic salt), wherein M⁺ is a cation such as Na⁺, K⁺, Li⁺, or NR₄ ⁺, wherein R, which can be the same or different, represents hydrogen or an organic group such as a substituted or unsubstituted aryl and/or alkyl group.

[0048] As other examples, the organic group may include at least one geminal bisphosphonic acid group, partial esters thereof, or salts thereof. By “geminal”, it is meant that the at least two phosphonic acid groups, partial esters thereof, or salts thereof are directly bonded to the same carbon atom. Such a group may also be referred to as a 1 ,1-diphosphonic acid group, partial ester thereof, or salt thereof.

[0049] An example of a geminal bisphosphonic acid group may have the formula — CQ(P H ) , or may be partial esters thereof or salts thereof. Q is bonded to the geminal position and may be H, R, OR, SR, or NR₂ wherein R, which can be the same or different when multiple are present, is selected from H, a C -C saturated or unsaturated, branched or unbranched alkyl group, a Ci-Ci₈ saturated or unsaturated, branched or unbranched acyl group, an aralkyl group, an alkaryl group, or an aryl group. For examples, Q may be H, R, OR, SR, or NR₂, wherein R, which can be the same or different when multiple are present, is selected from H, a O-i-Ob alkyl group, or an aryl group. As specific examples, Q is H, OH, or NH₂. Another example of a geminal bisphosphonic acid group may have the formula — (0H₂)_h00(R0₃H₂)₂, or may be partial esters thereof or salts thereof, wherein Q is as described above and n is 0 to 9, such as 1 to 9. In some specific examples, n is 0 to 3, such as 1 to 3, or n is either 0 or 1.

[0050] Still another example of a geminal bisphosphonic acid group may have the formula — X— (CH₂)_nCQ(P0₃H₂)₂, or may be partial esters thereof or salts thereof, wherein Q and n are as described above and X is an arylene, heteroarylene, alkylene, vinylidene, alkarylene, aralkylene, cyclic, or heterocyclic group. In specific examples,

X is an arylene group, such as a phenylene, naphthalene, or biphenylene group, which may be further substituted with any group, such as one or more alkyl groups or aryl groups. When X is an alkylene group, examples include substituted or unsubstituted alkylene groups, which may be branched or unbranched and can be substituted with one or more groups, such as aromatic groups. Examples of X include Ci-C-i₂ groups like methylene, ethylene, propylene, or butylene. X may be directly attached to the pigment, meaning there are no additional atoms or groups from the attached organic group between the pigment and X. X may also be further substituted with one or more functional groups. Examples of functional groups include R', OR', COR', COOR', OCOR', carboxylates, halogens, CN, NR'₂, SO3H, sulfonates, sulfates, NR'(COR'), CONR'₂, imides, N0₂, phosphates, phosphonates, N=NR', SOR', NR'S0₂R', and S0₂NR'₂, wherein R', which can be the same or different when multiple are present, is independently selected from hydrogen, branched or unbranched Ci-C₂o substituted or unsubstituted, saturated or unsaturated hydrocarbons, e.g., alkyl, alkenyl, alkynyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkaryl, or substituted or unsubstituted aralkyl.

[0051 ] Yet another example of a geminal bisphosphonic acid group may have the formula — X— Sp— (CH₂)_nCQ(P0₃H₂)₂, or may be partial esters thereof or salt thereof, wherein X, Q, and n are as described above. “Sp” is a spacer group, which, as used herein, is a link between two groups. Sp can be a bond or a chemical group.

Examples of chemical groups include, but are not limited to, — CO^ , — 0₂C— , — CO— , -OS0₂- -SO₃-, -SO2- -S0₂C₂H₄0- -S0₂C₂H₄S- -S0₂C₂H₄NR"-, -0-, -S-, -NR"-, — NR"CO— — CONR"— , -NR"C0₂-, -0₂CNR"-, — NR"CONR"—

— N(COR")CO- — CON(COR")— , -NR"C0CH(CH₂C0₂R")- and cyclic imides therefrom, — NR"C0CH₂CH(C0₂R")— and cyclic imides therefrom, -CH(CH₂C0₂R")C0NR"- and cyclic imides therefrom, -CH(C0₂R")CH₂C0NR" and cyclic imides therefrom (including phthalimide and maleimides of these), sulfonamide groups (including — S0₂NR"— and — NR"S0₂— groups), arylene groups, alkylene groups and the like. R", which can be the same or different when multiple are included, represents H or an organic group such as a substituted or unsubstituted aryl or alkyl group. In the example formula — X— Sp— (CH₂)_nCQ(P0₃H₂)₂ the two phosphonic acid groups or partial esters or salts thereof are bonded to X through the spacer group Sp. Sp may be — C0₂— , — 0₂C— , —0—, —NR"—, — NR"CO— , or -CONR"-, - S0₂NR"-, -S0₂CH₂CH₂NR"-, -S0₂CH₂CH₂0-, or — S0₂CH₂CH₂S— wherein R" is H or a C₁-C₆ alkyl group.

[0052] Still a further example of a geminal bisphosphonic acid group may have the formula — N— [(CH₂)_m(P0₃H₂)]₂, partial esters thereof, or salts thereof, wherein m, which can be the same or different, is 1 to 9. In specific examples, m is 1 to 3, or 1 or 2. As another example, the organic group may include at least one group having the formula — (CH₂)n— N— [(CH₂)_m(P0₃H₂)]₂, partial esters thereof, or salts thereof, wherein n is 0 to 9, such as 1 to 9, or 0 to 3, such as 1 to 3, and m is as defined above. Also, the organic group may include at least one group having the formula — X— (CH₂)_n— N— [(CH₂)m(P0₃H₂)]₂, partial esters thereof, or salts thereof, wherein X, m, and n are as described above, and, in an example, X is an arylene group. Still further, the organic group may include at least one group having the formula — X— Sp—

(CH₂)_n— N— [(CH₂)_m(P0₃H₂)]₂, partial esters thereof, or salts thereof, wherein X, m, n, and Sp are as described above.

[0053] Yet a further example of a geminal bisphosphonic acid group may have the formula — CR=C(P0₃H₂)₂, partial esters thereof, or salts thereof. In this example, R can be H, a CrCi₈ saturated or unsaturated, branched or unbranched alkyl group, a C₁-C₁₈ saturated or unsaturated, branched or unbranched acyl group, an aralkyl group, an alkaryl group, or an aryl group. In an example, R is H, a C₁-C₆ alkyl group, or an aryl group. [0054] The organic group may also include more than two phosphonic acid groups, partial esters thereof, or salts thereof, and may, for example include more than one type of group (such as two or more) in which each type of group includes at least two phosphonic acid groups, partial esters thereof, or salts thereof. For example, the organic group may include a group having the formula — X— [CQ(P03H₂)2]_P, partial esters thereof, or salts thereof. In this example, X and Q are as described above. In this formula, p is 1 to 4, e.g., 2.

[0055] In addition, the organic group may include at least one vicinal bisphosphonic acid group, partial ester thereof, or salts thereof, meaning that these groups are adjacent to each other. Thus, the organic group may include two phosphonic acid groups, partial esters thereof, or salts thereof bonded to adjacent or neighboring carbon atoms. Such groups are also sometimes referred to as 1 ,2-diphosphonic acid groups, partial esters thereof, or salts thereof. The organic group including the two phosphonic acid groups, partial esters thereof, or salts thereof may be an aromatic group or an alkyl group, and therefore the vicinal bisphosphonic acid group may be a vicinal alkyl or a vicinal aryl diphosphonic acid group, partial ester thereof, or salts thereof. For example, the organic group may be a group having the formula -C6FI3- (P03H₂)2, partial esters thereof, or salts thereof, wherein the acid, ester, or salt groups are in positions ortho to each other.

[0056] In other examples, the ionic or ionizable group (of the organic group attached to the pigment) is a sulfur-containing group. The at least one sulfur- containing group has at least one S=0 bond, such as a sulfinic acid group or a sulfonic acid group. Salts of sulfinic or sulfonic acids may also be used, such as -SO3^' X⁺, where X is a cation, such as Na⁺, FT, K⁺, NH₄ ⁺, Li⁺, Ca²⁺, Mg⁺, etc.

[0057] When the ionic or ionizable group is a carboxylic acid group, the group may be COOFI or a salt thereof, such as -COOX⁺, -(COOX⁺)2, or-(COOX⁺)3.

[0058] Examples of the self-dispersed pigments are commercially available as dispersions. Suitable commercially available self-dispersed pigment dispersions include those of the CAB-O-JET® 200 Series, manufactured by Cabot Corporation. Some specific examples include CAB-O-JET® 200 (black pigment), CAB-O-JET® 250C (cyan pigment), CAB-O-JET® 260M or 265M (magenta pigment) and CAB-O- JET® 270 (yellow pigment)). Other suitable commercially available self-dispersed pigment dispersions include those of the CAB-O-JET® 400 Series, manufactured by Cabot Corporation. Some specific examples include CAB-O-JET® 400 (black pigment), CAB-O-JET® 450C (cyan pigment), CAB-O-JET® 465M (magenta pigment) and CAB-O-JET® 470Y (yellow pigment)). Still other suitable commercially available self-dispersed pigment dispersions include those of the CAB-O-JET® 300 Series, manufactured by Cabot Corporation. Some specific examples include CAB-O-JET® 300 (black pigment) and CAB-O-JET® 352K (black pigment).

[0059] The self-dispersed pigment is present in an amount ranging from about 1 wt% active to about 6 wt% active based on a total weight of the thermal inkjet ink. In an example, the dispersed pigment is present in an amount ranging from about 2 wt% active to about 5 wt% active based on a total weight of the thermal inkjet ink. In another example, the self-dispersed pigment is present in an amount of about 3 wt% based on the total weight of the thermal inkjet ink. In still another example, the self- dispersed pigment is present in an amount of about 5 wt% active based on the total weight of the thermal inkjet ink.

[0060] For the pigment dispersions disclosed herein, it is to be understood that the pigment and separate dispersant or the self-dispersed pigment (prior to being incorporated into the ink formulation), may be dispersed in water alone or in combination with an additional water soluble or water miscible co-solvent, such as 2- pyrrolidone, 1-(2-hydroxyethyl)-2-pyrrolidone, glycerol, 2-methyl-1, 3-propanediol, 1,2- butane diol, diethylene glycol, triethylene glycol, tetraethylene glycol, or a combination thereof. It is to be understood however, that the liquid components of the pigment dispersion become part of the aqueous ink vehicle in the thermal inkjet ink.

[0061 ] Polyurethane-based Binder

[0062] Some examples of the thermal inkjet ink include a polyurethane-based binder. Examples of suitable polyurethane-based binders may be selected from the group consisting of a polyester-polyurethane binder, a polyether-polyurethane binder, a polycarbonate-polyurethane binder, and combinations thereof. Hybrids of any of these binders may also be used. [0063] In an example, the thermal inkjet ink includes the polyester-polyurethane binder. In an example, the polyester-polyurethane binder is a sulfonated polyester- polyurethane binder. The sulfonated polyester-polyurethane binder can include diaminesulfonate groups. In an example, the polyester-polyurethane binder is a sulfonated polyester-polyurethane binder, and is one of: i) an aliphatic compound including multiple saturated carbon chain portions ranging from C4 to C10 in length, and that is devoid of an aromatic moiety, or ii) an aromatic compound including an aromatic moiety and multiple saturated carbon chain portions ranging from C₄ to Cm in length.

[0064] In one example, the sulfonated polyester-polyurethane binder can be anionic. In further detail, the sulfonated polyester-polyurethane binder can also be aliphatic, including saturated carbon chains as part of the polymer backbone or as a side-chain thereof, e.g., C2 to C10, C3 to Cs, or C3 to C_& alkyl. The sulfonated polyester-polyurethane binder can also contain an alicyclic carbon moiety. These polyester-polyurethane binders can be described as “alkyl” or “aliphatic” because these carbon chains are saturated and because they are devoid of aromatic moieties. An example of an anionic aliphatic polyester-polyurethane binder that can be used is IMPRANIL® DLN-SD (Mw 133,000; Acid Number 5.2; Tg -47°C; Melting Point 175- 200°C) from Covestro. Example components used to prepare the IMPRANIL® DLN- SD or other similar anionic aliphatic polyester-polyurethane binders can include pentyl glycols (e.g., neopentyl glycol); C₄ to C10 alkyldiol (e.g., hexane-1 ,6-diol); C₄ to C10 alkyl dicarboxylic acids (e.g., adipic acid); C₄ to Cm alkyl diisocyanates (e.g., hexamethylene diisocyanate (HDI)); diamine sulfonic acids (e.g., 2-[(2- aminoethyl)amino]ethanesulfonic acid); etc.

[0065] Alternatively, the sulfonated polyester-polyurethane binder can be aromatic (or include an aromatic moiety) and can include aliphatic chains. An example of an aromatic polyester-polyurethane binder that can be used is DISPERCOLL® U42. Example components used to prepare the DISPERCOLL® U42 or other similar aromatic polyester-polyurethane binders can include aromatic dicarboxylic acids, e.g., phthalic acid; C₄ to C-m alkyl dialcohols (e.g., hexane-1 ,6-diol); C₄ to Cm alkyl di isocyanates (e.g., hexamethylene diisocyanate (HDI)); diamine sulfonic acids (e.g., 2-[(2-aminoethyl)amino]ethanesulfonic acid); etc.

[0066] Other types of polyester-polyurethanes can also be used, including IMPRANIL® DL 1380, IMPRANIL® DLS and IMPRANIL® DLH from Covestro and TAKELAC® W-5030, TAKELAC® WS-5000 from Mitsui.

[0067] Some examples of the polyester-polyurethane binders disclosed herein may have a weight average molecular weight (Mw) ranging from about 20,000 to about 300,000. In other examples, the weight average molecular weight can range from about 50,000 to about 500,000, from about 100,000 to about 400,000, or from about 150,000 to about 300,000.

[0068] Some examples of the polyester-polyurethane binders disclosed herein may have an acid number that ranges from about 1 mg/ g KOH to about 50 mg/g KOH. Some examples of the sulfonated polyester-polyurethane binder may have an acid number that ranges from about 1 mg KOH/g to about 200 mg KOH/g, from about 2 mg KOH/g to about 100 mg KOH/g, or from about 3 mg KOH/g to about 50 mg KOH/g. [0069] In an example of the thermal inkjet ink, the polyester-polyurethane binder has a weight average molecular weight ranging from about 20,000 to about 300,000 and an acid number ranging from about 1 mg KOH/g to about 50 mg KOH/g.

[0070] The average particle size (volume-weighted mean diameter) of the polyester-polyurethane binders disclosed herein may range from about 20 nm to about 500 nm. As examples, the sulfonated polyester-polyurethane binder can have an average particle size ranging from about 20 nm to about 500 nm, from about 50 nm to about 350 nm, or from about 100 nm to about 250 nm. The particle size of any solids herein, including the average particle size of the dispersed polymer binder, can be determined using a NAN OTRAC® Wave device, from Microtrac, e.g., NANOTRAC® Wave II or NANOTRAC® 150, etc., which measures particles size using dynamic light scattering. Average particle size can be determined using particle size distribution data generated by the NANOTRAC® Wave device.

[0071] Other examples of the ink include a polyether-polyurethane binder.

Examples of polyether-polyurethanes that may be used include IMPRANIL® LP DSB 1069, IMPRANIL® DLE, IMPRANIL® DAH, or IMPRANIL® DL 1116 (Covestro (Germany)); or HYDRAN® WLS-201 or HYDRAN® WLS-201K (DIC Corp. (Japan)); or TAKELAC® W-6061 T or TAKE LAC® WS-6021 (Mitsui (Japan)).

[0072] Still other examples of the ink include a polycarbonate-polyurethane binder. Examples of polycarbonate-polyurethanes that may be used as the polymeric binder include IMPRANIL® DLC-F or IMPRANIL® DL 2077 (Covestro (Germany)); or HYDRAN® WLS-213 (DIC Corp. (Japan)); or TAKELAC® W-6110 (Mitsui (Japan)). [0073] Acrylic Binder

[0074] Some examples of the thermal inkjet ink include an acrylic binder instead of the polyurethane-based binder. As such, in some examples, the polymeric binder is the acrylic binder.

[0075] The acrylic binder includes acrylic polymer particles. These acrylic polymer particles can form a stable dispersion in an aqueous medium, and this dispersion may be referred to as a latex dispersion. The latex dispersion may include the polymer particles dispersed in water or in water and a suitable co-solvent. This aqueous latex dispersion may be incorporated into a suitable ink vehicle to form examples of the thermal inkjet ink.

[0076] The acrylic binder may be anionic or non-ionic depending upon the monomers used.

[0077] In some examples, the acrylic polymer particles can include a polymerization product of monomers including: a copolymerizable surfactant; an aromatic monomer selected from styrene, an aromatic (meth)acrylate monomer, and an aromatic (meth)acrylamide monomer; and multiple aliphatic (meth)acrylate monomers or multiple aliphatic (meth)acrylamide monomers. The term “(meth)” indicates that the acrylamide, the acrylate, etc., may or may not include the methyl group. In one example, the acrylic polymer particles can include a polymerization product of a copolymerizable surfactant such as HITENOL™ BC-10, BC-30, KH-05, or KH-10. In another example, the acrylic polymer particles can include a polymerization product of styrene, methyl methacrylate, butyl acrylate, and methacrylic acid.

[0078] In another particular example, the acrylic polymer particles can include a first heteropolymer phase and a second heteropolymer phase. The first heteropolymer phase is a polymerization product of multiple aliphatic (meth)acrylate monomers or multiple aliphatic (meth)acrylamide monomers. The second heteropolymer phase can be a polymerization product of an aromatic monomer with a cycloaliphatic monomer, wherein the aromatic monomer is an aromatic (meth)acrylate monomer or an aromatic (meth)acrylamide monomer, and wherein the cycloaliphatic monomer is a cycloaliphatic (meth)acrylate monomer or a cycloaliphatic (meth)acrylamide monomer. The second heteropolymer phase can have a higher glass transition temperature than the first heteropolymer phase. The first heteropolymer composition may be considered a soft polymer composition and the second heteropolymers composition may be considered a hard polymer composition.

[0079] The two phases can be physically separated in the latex particles, such as in a core-shell configuration, a two-hemisphere configuration, smaller spheres of one phase distributed in a larger sphere of the other phase, interlocking strands of the two phases, and so on.

[0080] The first heteropolymer composition can be present in the acrylic polymer particles in an amount ranging from about 15 wt% to about 70 wt% of a total weight of the acrylic polymer particle and the second heteropolymer composition can be present in an amount ranging from about 30 wt% to about 85 wt% of the total weight of the acrylic polymer particle. In other examples, the first heteropolymer composition can be present in an amount ranging from about 30 wt% to about 40 wt% of a total weight of the acrylic polymer particle and the second heteropolymer composition can be present in an amount ranging from about 60 wt% to about 70 wt% of the total weight of the acrylic polymer particle. In one specific example, the first heteropolymer composition can be present in an amount of about 35 wt% of a total weight of the acrylic polymer particle and the second heteropolymer composition can be present in an amount of about 65 wt% of the total weight of the acrylic polymer particle.

[0081] As mentioned herein, the first heteropolymer phase can be polymerized from two or more aliphatic (meth)acrylate ester monomers or two or more aliphatic (meth)acrylamide monomers. The aliphatic (meth)acrylate ester monomers may be linear aliphatic (meth)acrylate ester monomers and/or cycloaliphatic (meth)acrylate ester monomers. Examples of the linear aliphatic (meth)acrylate ester monomers can include ethyl acrylate, ethyl methacrylate, benzyl acrylate, benzyl methacrylate, propyl acrylate, propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, butyl acrylate, butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, hexyl acrylate, hexyl methacrylate, isooctyl acrylate, isooctyl methacrylate, octadecyl acrylate, octadecyl methacrylate, lauryl acrylate, lauryl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxyhexyl acrylate, hydroxyhexyl methacrylate, hydroxyoctadecyl acrylate, hydroxyoctadecyl methacrylate, hydroxylauryl methacrylate, hydroxylauryl acrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, and combinations thereof. Examples of the cycloaliphatic (meth)acrylate ester monomers can include cyclohexyl acrylate, cyclohexyl methacrylate, methylcyclohexyl acrylate, methylcyclohexyl methacrylate, trimethylcyclohexyl acrylate, trimethylcyclohexyl methacrylate, tert- butylcyclohexyl acrylate, tert- butylcyclohexyl methacrylate, and combinations thereof.

[0082] Also as mentioned herein, the second heteropolymer phase can be polymerized from a cycloaliphatic monomer and an aromatic monomer. The cycloaliphatic monomer can be a cycloaliphatic (meth)acrylate monomer or a cycloaliphatic (meth)acrylamide monomer. The aromatic monomer can be an aromatic (meth)acrylate monomer or an aromatic (meth)acrylamide monomer. The cycloaliphatic monomer of the second heteropolymer phase can be cyclohexyl acrylate, cyclohexyl methacrylate, methylcyclohexyl acrylate, methylcyclohexyl methacrylate, trimethylcyclohexyl acrylate, trimethylcyclohexyl methacrylate, tert- butylcyclohexyl acrylate, fe/f-butylcyclohexyl methacrylate, or a combination thereof.

In still further examples, the aromatic monomer of the second heteropolymer phase can be 2-phenoxyethyl methacrylate, 2-phenoxyethyl acrylate, phenyl propyl methacrylate, phenyl propyl acrylate, benzyl methacrylate, benzyl acrylate, phenylethyl methacrylate, phenylethyl acrylate, benzhydryl methacrylate, benzhydryl acrylate, 2- hydroxy-3-phenoxypropyl acrylate, 2-hydroxy-3-phenoxypropyl methacrylate, N-benzyl methacrylamide, N-benzyl acrylamide, N,N-diphenyl methacrylamide, N,N-diphenyl acrylamide, naphthyl methacrylate, naphthyl acrylate, phenyl methacrylate, phenyl acrylate, or a combination thereof. [0083] The acrylic polymer particles can have an average particle size (volume- weighted mean diameter) ranging from 20 nm to 500 nm, from 50 nm to 350 nm, or from 150 nm to 270 nm.

[0084] In some examples, the acrylic polymer particles can be prepared by flowing multiple monomer streams into a reactor. An initiator can also be included in the reactor. The initiator may be selected from a persulfate, such as a metal persulfate or an ammonium persulfate. In some examples, the initiator may be selected from a sodium persulfate, ammonium persulfate or potassium persulfate. The preparation process may be performed in water, resulting in the aqueous latex dispersion.

[0085] Examples of anionic acrylic binder latex dispersions include JANTEX™ Binder 924 and JANTEX™ Binder 45 NRF (both of which are available from Jantex). Other examples of anionic acrylic binder latex dispersions include TEXICRYL™ 13- 216, TEXICRYL™ 13-217, TEXICRYL™ 13-220, TEXICRYL™ 13-294, TEXICRYL™ 13- 295, TEXICRYL™ 13-503, and TEXICRYL™ 13-813 (each of which is available from Scott Bader). Still other examples of anionic acrylic binder latex dispersions include TUBIFAST™ AS 4010 FF, TUBIFAST™ AS 4510 FF, and TUBIFAST™ AS 5087 FF (each of which is available from CHT).

[0086] Examples of non-ionic acrylic binder latex dispersions include PRINTRITE™ 595, PRINTRITE™ 2015, PRINTRITE™ 2514, PRINTRITE™ 9691 , and PRINTRITE™ 96155 (each of which is available from Lubrizol Corporation). Another example of a non-ionic acrylic latex binder dispersion includes TEXICRYL™ 13-440 (available from Scott Bader).

[0087] In some examples of the thermal inkjet ink, the polymeric binder (either the polyurethane-based binder or the acrylic binder) is present in an amount ranging from about 1 wt% active to about 20 wt% active, based on a total weight of the thermal inkjet ink. In other examples, the polymeric binder can be present, in the thermal inkjet ink, in an amount ranging from about 2 wt% active to about 15 wt% active, or from about from about 3 wt% active to about 11 wt% active, or from about 4 wt% active to about 10 wt% active, or from about 1 wt% active to about 6 wt% active, each of which is based on the total weight of the thermal inkjet ink. [0088] Prior to being incorporated into the ink vehicle, the polymeric binder (either the polyurethane-based binder or the acrylic binder) may be dispersed in water alone or in combination with an additional water soluble or water miscible co-solvent, such as 2-pyrrolidone, 1-(2-hydroxyethyl)-2-pyrrolidone, glycerol, 2-methyl-1 ,3-propanediol,

1 ,2-butane diol, diethylene glycol, triethylene glycol, tetraethylene glycol, or a combination thereof. It is to be understood however, that the liquid components of the binder dispersion become part of the vehicle in the thermal inkjet ink.

[0089] Blocked Polyisocyanate Crosslinker

[0090] The isocyanate groups of the blocked polyisocyanate crosslinker can be reactive as crosslinkers when exposed to thermal curing after being printed on the textile fabric. In contrast, the isocyanate groups can remain stable within the thermal inkjet ink and within the inkjet applicator due to a blocking group that is attached to the isocyanate(s). Thus, the term “blocked polyisocyanate” refers to compounds with multiple isocyanate groups where a plurality of the isocyanate groups are coupled to a chemical moiety that stabilizes the isocyanate group so that they remain available for reaction after being printed on the textile fabric. The chemical moiety that prevents the isocyanate groups from reacting in the thermal inkjet ink and in the inkjet applicator is referred to herein as a “blocking group.” This blocking group is capable of being deblocked, i.e. , dissociated from the isocyanate group, when exposed to a suitable deblocking temperature. Removal of the blocking group converts the blocked polyisocyanate to a reactive species, referred to as a “deblocked polyisocyanate.” Deblocking can occur by heating the blocked polyisocyanate to a temperature where dissociation of the blocking group can occur. As mentioned herein, deblocking can occur over a range of temperatures, and the “initial deblocking temperature” refers to the temperature at which deblocking is first observed. As noted herein, the initial deblocking temperature of the deblocking group may be reached during a firing event, however, the duration of the firing event is so short that the deblocking reaction is either not initiated within the inkjet applicator, or is initiated but does not reach the activation energy needed to drive the reaction forward.

[0091] In an example disclosed herein, the initial deblocking temperature is at least 150°C. This means that the temperature at which deblocking is first observed, e.g., using FTIR, DSC, and/or TGA, is 150°C or higher. In the examples disclosed herein, the initial deblocking temperature may range from about 150°C to about 240°C. As mentioned, deblocking may take place over a temperature range, and thus the activation energy needed to drive the reaction forward and to completion is at a higher temperature than the initial deblocking temperature. In an example, the temperature range over which deblocking takes place may be from 150°C to about 270°C. As specific examples, the deblocking temperature range of e-caprolactam blocked 4,4'- methylenebis(cyclohexyl isocyanate) (as measured by TGA) may range from about 155°C to about 230°C; the deblocking temperature range of benzotriazole blocked 4,4'-methylenebis(cyclohexyl isocyanate) (as measured by TGA) may range from about 160°C to about 250°C; and the deblocking temperature range of e-caprolactam and benzotriazole blocked 4,4'-methylenebis(cyclohexyl isocyanate) (as measured by TGA) may range from about 170°C to about 250°C. Some blocked polyisocyanates have an initial deblocking temperature below 150°C, but these have been found to deleteriously affect the jettability performance of the fluid from a thermal inkjet applicator.

[0092] The deblocking reaction can take place over a time period ranging from about 1 minute to about 60 minutes. In another example, the deblocking reaction can take place over a time period ranging from about 10 minutes to about 30 minutes. In some instances, the deblocking reaction may be even longer.

[0093] During the deblocking of a blocked polyisocyanate, reaction can occur according to Formulas I or II, as follows:

Formula I Formula II

In Formula I and Formula II above, R can be a linking group that connects the blocked isocyanate group shown to any organic group that includes other blocked isocyanates (as the blocked isocyanates used in accordance with the present disclosure is a blocked “poly” isocyanates, meaning that the compound includes more than one isocyanate group). For example, R can independently include a C2 to C10 branched or straight-chained alkyl, C6 to C20 alicyclic, or a combination thereof. The asterisk (*) denotes the organic group with additional blocked isocyanate groups that extend beyond the R linking group (see Formula III below, for example, which illustrates the balance of a polyisocyanate trimer including two additional isocyanate groups). Additionally, R' in Formula I and Formula II can be any organic group that can be coupled to the hydroxyl or amine group to replace the blocking group (BL) of the isocyanate, typically liberating a hydrogen to associate with the blocking group, as shown. In one example, R'-OFI or R'-NF^ can be a residual group present in the polyurethane-based binder or the acrylic binder of the thermal inkjet ink, and in other examples, the R'-OFI group can be present in cotton, cotton blend, or wool textile fabrics, and the R'-NFb group can be present in nylon textile fabrics. As such, the deblocked, active isocyanate groups can crosslink with the polymeric binder and/or with the textile fabric when the blocked polyisocyanate is deblocked on the textile fabric.

[0094] The blocked polyisocyanate crosslinker may be an aliphatic blocked polyisocyanate crosslinker. An aliphatic polyisocyanate may be more desirable as they tend to have higher deblocking temperatures than aromatic polyisocyanates. In one example, the polyisocyanate of the aliphatic blocked polyisocyanate crosslinker is selected from the group consisting of 4,4'-dicyclohexylmethane diisocyanate (F½MDI), hexamethylene diisocyanate trimer (HDI trimer), hexamethylene diisocyanate biuret (HDI biuret), isophorone diisocyanate (IPDI), and isophorone diisocyanate trimer (IPDI trimer).

[0095] The blocking group of the aliphatic blocked polyisocyanate crosslinker is selected from the group consisting of e-caprolactam, an alcohol, a phenol, an oxime, an imidazole or imidazoline, a triazole, uretdione, and 2-oxo-1 ,3-diazepane-1- carboxylate. In an example, the blocking group is the alcohol and the alcohol is selected from the group consisting of ethanol, isopropanol, and butanol; orthe blocking group is the phenol and the phenol is selected from the group consisting of phenol and o-Cresol; or the blocking group is the oxime and the oxime is benzophenone oxime; or the blocking group is the imidazole and the imidazole is selected from the group consisting imidazole, 2-methylimidazole, and 2-phenylimidazole; or the blocking group is the triazole and the triazole is benzotriazole. In one example, the blocking group attached to any of the previously listed aliphatic polyisocyanates is selected from the group consisting of e-caprolactam, ethanol, isopropanol, butanol, phenol, o-Cresol, benzophenone oxime, imidazole, 2-methylimidazole, 2-phenylimidazole, benzotriazole, uretdione, and 2-oxo-1 ,3-diazepane-1-carboxylate.

[0096] In one example, the blocked polyisocyanate crosslinker can include a blocked polyisocyanate trimer. The blocked polyisocyanate trimer can have the structure shown in Formula III, as follows:

(NCO)₃R3(NHCO)₃(BL)₃ Formula III where R can independently include a C2 to C10 branched or straight-chained alkyl, C6 to C20 alicyclic, or a combination thereof; BL can include any of the blocking groups set forth herein; and x can be from 0 to 1.

[0097] More specific examples of the R groups include those present to complete isophorone diisocyanate (IPDI) trimers, e.g., methylated alicyclic R groups (sometimes also referred to as cycloaliphatic groups) such as present in N,N',N"-Tris(5-isocyanato- 1 ,3,3-trimethylcyclohexylmethyl)-2,4,6-triketohexahydrotriazine; or hexanemethylene- 1 ,6-di isocyanate (HDI) trimers, e.g., where R may be C2 to C10 alkyl, C2 to C8 alkyl, C2 to C6 alkyl, C3 to C8 alkyl, C4 to C8 alkyl, or C4 to C10 alkyl.

[0098] An example of a suitable blocked polyisocyanate trimer has the structure shown in Formula IV, as follows:

Formula IV where R is independently a C2 to C10 branched or straight-chained alkyl, C6 to C20 alicyclic, or a combination thereof; and Z independently includes the blocking group (the “BL” groups described herein).

[0099] Some specific examples of commercially available aliphatic blocked polyisocyanates that may be used in the thermal inkjet ink include BAYBOND® XL 3674 from Covestro (e-caprolactam blocked hexamethylene diisocyanate, 30% solids in water, deblocking temp >170°C, e.g., from 170°C to 190°C), BAYBOND® XL 7270 from Covestro (e-caprolactam blocked hexamethylene diisocyanate, 30% solids in water, deblocking temp >170°C, e.g., from 170°C to 190°C), and BAYBOND® XL 825 from Covestro (e-caprolactam blocked hexamethylene diisocyanate, 30% solids in water, deblocking temp >170°C, e.g., from 170°C to 190°C).

[0100] In an example of the thermal inkjet ink, the blocked polyisocyanate is present in an amount ranging from about 0.2 wt% active to about 5 wt% active based on a total weight of the thermal inkjet ink. In further examples, the blocked polyisocyanate is present in an amount ranging from about 0.5 wt% active to about 4 wt% active; or from about 3 wt% active to about 5 wt% active; or from about 1 wt% active to about 2 wt% active, based on a total weight of the thermal inkjet ink.

[0101] The blocked polyisocyanate may be in the form of particles in water. The particles consist of the blocked polyisocyanate crosslinker. Thus, in an example, the blocked polyisocyanate crosslinker is in the form of uncoated solid particles.

[0102] Prior to being incorporated into the ink vehicle, the blocked polyisocyanate may be dispersed in water alone or in combination with an additional water soluble or water miscible co-solvent, such as 2-pyrrolidone, 1-(2-hydroxyethyl)-2-pyrrolidone, glycerol, 2-methyl-1 ,3-propanediol, 1,2-butane diol, diethylene glycol, triethylene glycol, tetraethylene glycol, or a combination thereof. It is to be understood however, that the liquid components of the blocked polyisocyanate dispersion become part of the vehicle in the thermal inkjet ink.

[0103] Aqueous Ink Vehicle

[0104] In addition to the pigment, the polymeric binder, and the blocked polyisocyanate, the thermal inkjet ink includes an aqueous ink vehicle.

[0105] As used herein, the term “aqueous ink vehicle” may refer to the liquid fluid with which the pigment (dispersion), the polymeric binder (dispersion), and the blocked polyisocyanate (dispersion) are mixed to form the thermal inkjet ink. A wide variety of vehicles may be used with the thermal inkjet ink composition(s) of the present disclosure. The aqueous ink vehicle includes water. In addition to water, the aqueous ink vehicle may also include a co-solvent and an additive selected from the group consisting of an anti-kogation agent, an anti-decel agent, a surfactant, an antimicrobial agent, a pH adjuster, and combinations thereof. In an example, the aqueous ink vehicle consists of water and the co-solvent, the anti-kogation agent, the anti-decel agent, the surfactant, the antimicrobial, the pH adjuster, or a combination thereof. [0106] The aqueous ink vehicle may include co-solvent(s). The co-solvent(s) may be present in an amount ranging from about 2 wt% to about 30 wt% (based on the total weight of the thermal inkjet ink).

[0107] In an example, the co-solvent is glycerol. Other examples of co-solvents include alcohols, aliphatic alcohols, aromatic alcohols, diols, glycol ethers, polyglycol ethers, caprolactams, formamides, acetamides, and long chain alcohols. Examples of such compounds include primary aliphatic alcohols, secondary aliphatic alcohols, 1,2- alcohols, 1,3-alcohols, 1,5-alcohols, ethylene glycol alkyl ethers, propylene glycol alkyl ethers, higher homologs (C₆-Ci2) of polyethylene glycol alkyl ethers, N-alkyl caprolactams, unsubstituted caprolactams, both substituted and unsubstituted formamides, both substituted and unsubstituted acetamides, and the like. Specific examples of alcohols may include ethanol, isopropyl alcohol, butyl alcohol, and benzyl alcohol. Other specific examples include 2-ethyl-2-(hydroxymethyl)-1 ,3-propane diol (EPHD), dimethyl sulfoxide, sulfolane, and/or alkyldiols such as 1 ,2-hexanediol.

[0108] The co-solvent may also be a polyhydric alcohol or a polyhydric alcohol derivative. Examples of polyhydric alcohols may include ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1 ,5-pentanediol, 1 ,2- hexanediol, 1 ,2,6-hexanetriol, glycerin, trimethylolpropane, and xylitol. Examples of polyhydric alcohol derivatives may include an ethylene oxide adduct of diglycerin. [0109] The co-solvent may also be a nitrogen-containing solvent. Examples of nitrogen-containing solvents may include 2-pyrrolidone, 1-(2-hydroxyethyl)-2- pyrrolidone, N-methyl-2-pyrrolidone, cyclohexylpyrrolidone, and triethanolamine.

[0110] An anti-kogation agent may also be included in the aqueous ink vehicle of a thermal inkjet ink. Kogation refers to the deposit of dried ink solids on a heating element of a thermal inkjet printhead. Anti-kogation agent(s) is/are included to assist in preventing the buildup of kogation. In some examples, the anti-kogation agent may improve the jettability of the thermal inkjet ink. The anti-kogation agent may be present in the thermal inkjet ink in an amount ranging from about 0.1 wt% active to about 1.5 wt% active, based on the total weight of the thermal inkjet ink. In an example, the anti-kogation agent is present in an amount of about 0.5 wt% active, based on the total weight of the thermal inkjet ink.

[0111] Examples of suitable anti-kogation agents include oleth-3-phosphate (commercially available as CRODAFOS™ 03A or CRODAFOS™ N-3A) or dextran 500k. Other suitable examples of the anti-kogation agents include CRODAFOS™ FICE (phosphate-ester from Croda Int.), CRODAFOS® N10 (oleth-10-phosphate from Croda Int.), or DISPERSOGEN® LFH (polymeric dispersing agent with aromatic anchoring groups, acid form, anionic, from Clariant), etc. [0112] The aqueous ink vehicle may include anti-decel agent(s). The anti-decel agent may function as a humectant. Decel refers to a decrease in drop velocity over time with continuous firing. In the examples disclosed herein, the anti-decel agent (s) is/are included to assist in preventing decel. In some examples, the anti-decel agent may improve the jettability of the thermal inkjet ink. The anti-decel agent(s) may be present in an amount ranging from about 0.2 wt% active to about 5 wt% active (based on the total weight of the ink composition). In an example, the anti-decel agent is present in the ink composition in an amount of about 1 wt% active, based on the total weight of the thermal inkjet ink.

[0113] An example of a suitable anti-decel agent is ethoxylated glycerin having the following formula:

H₂C^~~ 0{CH₂CH₂0)_aH HC — 0{CH₂CH₂0)_bH H₂C ~0{CH₂CH₂0)_cH in which the total of a+b+c ranges from about 5 to about 60, or in other examples, from about 20 to about 30. An example of the ethoxylated glycerin is LIPONIC® EG-1 (LEG-1, glycereth-26, a+b+c=26, available from Lipo Chemicals).

[0114] The aqueous ink vehicle of the thermal inkjet ink may also include surfactant(s). In any of the examples disclosed herein, the surfactant may be present in an amount ranging from about 0.01 wt% active to about 5 wt% active (based on the total weight of the thermal inkjet ink). In an example, the surfactant is present in the thermal inkjet ink composition in an amount ranging from about 0.05 to about 3 wt%, based on the total weight of the thermal inkjet ink.

[0115] The surfactant may include anionic and/or non-ionic surfactants. Examples of the anionic surfactant may include alkylbenzene sulfonate, alkylphenyl sulfonate, alkylnaphthalene sulfonate, higher fatty acid salt, sulfate ester salt of higher fatty acid ester, sulfonate of higher fatty acid ester, sulfate ester salt and sulfonate of higher alcohol ether, higher alkyl sulfosuccinate, polyoxyethylene alkylether carboxylate, polyoxyethylene alkylether sulfate, alkyl phosphate, and polyoxyethylene alkyl ether phosphate. Specific examples of the anionic surfactant may include dodecylbenzenesulfonate, isopropylnaphthalenesulfonate, monobutylphenylphenol monosulfonate, monobutylbiphenyl sulfonate, monobutylbiphenylsul fonate, and dibutylphenylphenol disulfonate. Examples of the non-ionic surfactant may include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, glycerin fatty acid ester, polyoxyethylene glycerin fatty acid ester, polyglycerin fatty acid ester, polyoxyethylene alkylamine, polyoxyethylene fatty acid amide, alkylalkanolamide, polyethylene glycol polypropylene glycol block copolymer, acetylene glycol, and a polyoxyethylene adduct of acetylene glycol. Specific examples of the non-ionic surfactant may include polyoxyethylenenonyl phenylether, polyoxyethyleneoctyl phenylether, and polyoxyethylenedodecyl. Further examples of the non-ionic surfactant may include silicon surfactants such as a polysiloxane oxyethylene adduct; fluorine surfactants such as perfluoroalkylcarboxylate, perfluoroalkyl sulfonate, and oxyethyleneperfluoro alkylether; and biosurfactants such as spiculisporic acid, rhamnolipid, and lysolecithin. [0116] In some examples, the aqueous ink vehicle may include a silicone-free alkoxylated alcohol surfactant such as, for example, TEGO® Wet 510 (Evonik Industries) and/or a self-emulsifiable wetting agent based on acetylenic diol chemistry, such as, for example, SURFYNOL® SE-F (Evonik Industries)). Other suitable commercially available surfactants include SURFYNOL® 465 (ethoxylatedacetylenic diol), SURFYNOL® 440 (an ethoxylated low-foam wetting agent) SURFYNOL® CT- 211 (now CARBOWET® GA-211, non-ionic, alkylphenylethoxylate and solvent free), and SURFYNOL® 104 (non-ionic wetting agent based on acetylenic diol chemistry), (all of which are from Evonik Industries); ZONYL® FSO (a.k.a. CAPSTONE®, which is a water-soluble, ethoxylated non-ionic fluorosurfactant from E.l. DuPont de Nemours and Company); TERGITOL® TMN-3 and TERGITOL® TMN-6 (both of which are branched secondary alcohol ethoxylate, non-ionic surfactants), and TERGITOL® 15- S-3, TERGITOL® 15-S-5, and TERGITOL® 15-S-7 (each of which is a secondary alcohol ethoxylate, non-ionic surfactant) (all of the TERGITOL® surfactants are available from The Dow Chemical Co.); and BYK® 345, BYK® 346, BYK® 347, BYK® 348, BYK® 349 (each of which is a silicone surfactant) (all of which are available from BYK Chemie).

[0117] The aqueous ink vehicle may also include an antimicrobial agent. Antimicrobial agents are also known as biocides and/or fungicides. In an example, the total amount of antimicrobial agent(s) in the thermal inkjet ink ranges from about 0.01 wt% active to about 0.05 wt% active (based on the total weight of the thermal inkjet ink). In another example, the total amount of antimicrobial agent(s) in the thermal inkjet ink is about 0.044 wt% active (based on the total weight of the thermal inkjet ink). In some instances, the antimicrobial agent may be present in the pigment dispersion that is mixed with the aqueous ink vehicle.

[0118] Examples of suitable antimicrobial agents include the NUOSEPT® (Ashland Inc.), UCARCIDE™ or KORDEK™ or ROCIMA™ (Dow Chemical Co.), PROXEL® (Arch Chemicals) series, ACTICIDE® B20 and ACTICIDE® M20 and ACTICIDE®

MBL (blends of 2-methyl-4-isothiazolin-3-one (MIT), 1,2-benzisothiazolin-3-one (BIT) and Bronopol) (Thor Chemicals), AXIDE™ (Planet Chemical), NIPACIDE™ (Clariant), blends of 5-chloro-2-methyl-4-isothiazolin-3-one (CIT or CMIT) and MIT under the tradename KATHON™ (Dow Chemical Co.), and combinations thereof.

[0119] The aqueous ink vehicle may also include a pH adjuster. The pH adjuster may be included in the thermal inkjet ink to achieve a desired pH of greater than 7. Suitable pH ranges for examples of the thermal inkjet ink can be from greater than 7 to about 11 , from greater than 7 to about 10, from about 7.2 to about 10, from about 7.5 to about 10, from about 8 to about 10, from about 7 to about 9, from about 7.2 to about 9, from about 7.5 to about 9, from about 8 to about 9, from about 7 to about 8.5, from about 7.2 to about 8.5, from about 7.5 to about 8.5, from about 8 to about 8.5, from about 7 to about 8, from about 7.2 to about 8, or from about 7.5 to about 8.

[0120] Examples of suitable pH adjusters for the aqueous ink vehicle of the thermal inkjet ink include metal hydroxide bases, such as potassium hydroxide (KOH), sodium hydroxide (NaOH), etc. Other examples of suitable pH adjusters for the thermal inkjet ink include acids, such as nitric acid or methanesulfonic acid, etc. In an example, the metal hydroxide base or the acid may be added to the thermal inkjet ink in an aqueous solution, such as an aqueous solution including 5 wt% of the metal hydroxide base (e.g., a 5 wt% active potassium hydroxide aqueous solution) or including 99% methanesulfonic acid (e.g., a 99 wt% active methanesulfonic acid aqueous solution). [0121] In an example, the total amount of pH adjuster(s) in the aqueous ink vehicle ranges from greater than 0 wt% to about 0.5 wt% (based on the total weight of the aqueous ink vehicle). In another example, the total amount of pH adjuster(s) in the aqueous ink vehicle ranges from about 0.01 wt% to about 0.2 wt%. In another example, the total amount of pH adjuster(s) in the aqueous ink vehicle is about 0.03 wt% (based on the total weight of the aqueous ink vehicle). The amount of pH adjuster added depends on the desired pH, and the pH adjuster may be added until the desired pH of the aqueous ink vehicle is achieved.

[0122] The viscosity of the thermal inkjet ink may be adjusted for a thermal inkjet printer by adjusting the co-solvent level and/or adding a viscosity modifier. For thermal inkjet printing, the viscosity of the thermal inkjet ink may be modified to range from about 1 centipoise (cP) to about 9 cP (measured at 20°C to 25°C and a shear rate of about 3,000 Hz).

[0123] The balance of the thermal inkjet ink is water. In an example, deionized or another form of purified water may be used. The water included in the thermal inkjet ink may be: i) part of the pigment dispersion and/or binder dispersion and/or blocker polyisocyanate dispersion and/or ii) part of the aqueous ink vehicle. For the thermal inkjet inks disclosed herein, the aqueous ink vehicle includes at least 70% by weight of water.

[0124] In one example, the thermal inkjet ink includes the pigment present in an amount ranging from about 3 wt% active to about 4 wt% active; the aliphatic blocked polyisocyanate crosslinker present in an amount ranging from about 1 wt% active to about 2 wt% active; and the polymeric binder present in an amount ranging from about 1 wt% active to about 6 wt% active. [0125] Textile Printing Kits

[0126] The thermal inkjet ink may be included in a thermal inkjet ink textile printing kit. Three examples of the thermal inkjet ink textile printing kit 16A, 16B, and 16C are shown in Fig. 1.

[0127] The first example of the thermal inkjet ink textile printing kit 16A includes the thermal inkjet ink 10. In one example of the kit 16A, the thermal inkjet ink 10 includes a pigment, a polymeric binder selected from the group consisting of polyurethane- based binder and an acrylic binder, a blocked polyisocyanate crosslinker including a blocking group having an initial deblocking temperature of at least 150°C, and an aqueous ink vehicle. In another example of the kit 16A, the thermal inkjet ink 10 includes a pigment; a polymeric binder selected from the group consisting of polyurethane-based binder and an acrylic binder; an aliphatic blocked polyisocyanate crosslinker, wherein a polyisocyanate of the aliphatic blocked polyisocyanate crosslinker is selected from the group consisting of 4,4'-dicyclohexylmethane diisocyanate, hexamethylene diisocyanate trimer, hexamethylene diisocyanate biuret, isophorone diisocyanate, and isophorone diisocyanate trimer, and a blocking group of the aliphatic blocked polyisocyanate crosslinker is selected from the group consisting of e-caprolactam, ethanol, isopropanol, butanol, phenol, o-Cresol, benzophenone oxime, imidazole, 2-methylimidazole, 2-phenylimidazole, benzotriazole, uretdione, and 2-oxo-1,3-diazepane-1-carboxylate; and an aqueous ink vehicle including an anti- kogation agent.

[0128] The second example of the thermal inkjet ink textile printing kit 16B includes an example of the thermal inkjet ink 10 and a fixer fluid 12. Any example of the thermal inkjet ink 10 disclosed herein may be used. The fixer fluid 12 includes a multivalent metal salt and an aqueous fixer vehicle. Examples of the fixer fluid 12 are described in detail herein, and any example of the fixer fluid 12 may be used in the thermal inkjet ink textile printing kit 16B.

[0129] The third example of the thermal inkjet ink textile printing kit 16C includes an example of the thermal inkjet ink 10, an example of the fixer fluid 12, and a textile fabric 14. Any example of the thermal inkjet ink 10 disclosed herein may be used in the kit 16C. Any example of the fixer fluid 12 disclosed herein may be used in the kit 16C. Any suitable textile fabric 14 may be used, and in one example, the textile fabric

14 is selected from the group consisting of polyester fabrics, polyester blend fabrics, cotton fabrics, cotton blend fabrics, nylon fabrics, nylon blend fabrics, silk fabrics, silk blend fabrics, wool fabrics, wool blend fabrics, and combinations thereof.

[0130] In the examples of the thermal inkjet ink textile printing kit 16B and 16C, the fixer fluid 12 and the thermal inkjet ink 10 may be maintained in separate containers (e.g., respective reservoirs/fluid supplies of respective inkjet cartridges/pens) or separate compartments (e.g., respective reservoirs/fluid supplies) in a single container (e.g., inkjet cartridge/pen).

[0131] Fixer Fluid

[0132] As mentioned, examples of the fixer fluid 12 that may be used in the thermal inkjet ink textile printing kits 16B and 16C include a multivalent metal salt and an aqueous vehicle (referred to herein as the aqueous fixer vehicle).

[0133] The multivalent metal salt includes a multivalent metal cation and an anion. In an example, the multivalent metal salt includes a multivalent metal cation selected from the group consisting of a calcium cation, a magnesium cation, a zinc cation, an iron cation, an aluminum cation, and combinations thereof; and an anion selected from the group consisting of a chloride anion, an iodide anion, a bromide anion, a nitrate anion, a carboxylate anion, a sulfonate anion, a sulfate anion, and combinations thereof.

[0134] It is to be understood that the multivalent metal salt (containing the multivalent metal cation) may be present in any suitable amount. In an example, the metal salt is present in an amount ranging from about 2 wt% to about 15 wt% based on a total weight of the fixer fluid 12. In further examples, the metal salt is present in an amount ranging from about 4 wt% to about 12 wt%; or from about 5 wt% to about

15 wt%; or from about 6 wt% to about 10 wt%, based on a total weight of the fixer fluid 12.

[0135] As used herein, the term “aqueous fixer vehicle” may refer to the liquid fluid in which the multivalent metal salt is mixed to form the fixer fluid 12. [0136] In an example of the fixer fluid 12, the aqueous fixer vehicle includes water and a co-solvent. Examples of suitable co-solvents for the fixer fluid 12 include any of the water soluble or water miscible co-solvents set forth herein for the thermal inkjet ink 10. In one example, the co-solvent is selected from the group consisting of glycerol, ethoxylated glycerol, 2-methyl-1 ,3-propanediol, trimethylolpropane, 1,2- propanediol, dipropylene glycol, and combinations thereof. Other suitable examples of co-solvents include polyhydric alcohols or simple carbohydrates (e.g., trehalose). Still further examples of the fixer fluid 12 co-solvent(s) may include alcohols (e.g., diols), ketones, ketoalcohols, ethers (e.g., the cyclic ether tetrahydrofuran (THF), and others, such as thiodiglycol, sulfolane, 2-pyrrolidone, 1-(2-hydroxyethyl)-2-pyrrolidone,1 ,3- dimethyl-2-imidazolidinone and caprolactam; glycols such as ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, trimethylene glycol, butylene glycol, and hexylene glycol; addition polymers of oxyethylene or oxypropylene such as polyethylene glycol, polypropylene glycol and the like; triols such as glycerol (as mentioned above) and 1 ,2,6-hexanetriol; lower alkyl ethers of polyhydric alcohols, such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl, and diethylene glycol monoethyl ether; and lower dialkyl ethers of polyhydric alcohols, such as diethylene glycol dimethyl or diethyl ether.

[0137] Whether used alone or in combination, the total amount of the co-solvent(s) may be present in the fixer fluid 12 in an amount ranging from about 5 wt% to about 25 wt% based on a total weight of the fixer fluid 12. The amounts in this range may be particularly suitable for the composition when it is to be dispensed from a thermal inkjet printhead. In another example, the total amount of the co-solvent(s) may be present in the fixer fluid 12 in an amount ranging from about 10 wt% to about 18 wt% based on a total weight of the fixer fluid 12.

[0138] It is to be understood that water is present in addition to the co-solvent(s) and makes up a balance of the fixer fluid 12. As such, the weight percentage of the water present in the fixer fluid 12 will depend, in part, upon the weight percentages of the other components. The water may be purified water or deionized water. [0139] An example of the fixer fluid 12 further comprises an additive selected from the group consisting of a surfactant, a chelating agent, a buffer, an antimicrobial agent, and combinations thereof.

[0140] Some examples of the fixer fluid 12 further include a surfactant. The surfactant may be any surfactant that aids in wetting, but that does not deleteriously interact with the salt in the fixer fluid 12 or with the blocked polyisocyanate in the thermal inkjet ink 10. As such, in an example, the surfactant in the fixer fluid 12 is selected from the group consisting of a non-ionic surfactant and a zwitterionic surfactant. The amount of the surfactant that may be present in the fixer fluid 12 is 2 wt% active or less (with the lower limit being above 0) based on the total weight of the fixer fluid 12. In some examples, the amount of the surfactant ranges from about 0.05 wt% active to about 1 wt% active based on the total weight of the fixer fluid 12.

[0141] Examples of suitable non-ionic surfactants include non-ionic fluorosurfactants, non-ionic acetylenic diol surfactants, non-ionic ethoxylated alcohol surfactants, non-ionic silicone surfactants, and combinations thereof. Several commercially available non-ionic surfactants that can be used in the formulation of the fixer fluid 12 include ethoxylated alcohols/secondary alcohol ethoxylates such as those from the TERGITOL® series (e.g., TERGITOL® 15-S-30, TERGITOL® 15-S-9, TERGITOL® 15-S-7), manufactured by Dow Chemical; surfactants from the SURFYNOL® series (e.g., SURFYNOL® SE-F (i.e. , a self-emulsifiable wetting agent based on acetylenic diol chemistry), SURFYNOL® 440 and SURFYNOL® 465 (i.e., ethoxylated 2,4,7,9-tetramethyl 5 decyn-4,7-diol)) manufactured by Evonik Industries, and the DYNOL™ series (e.g., DYNOL™ 607 and DYNOL™ 604) manufactured by Evonik Industries; fluorinated surfactants, such as those from the ZONYL® family (e.g., ZONYL® FSO and ZONYL® FSN surfactants), manufactured by E.l. DuPont de Nemours and Company; alkoxylated surfactants such as TEGO® Wet 510 manufactured by Evonik Industries; fluorinated POLYFOX® non-ionic surfactants (e.g., PF159 non-ionic surfactants), manufactured by Omnova; silicone surfactants, such as those from BYK® 340 series (e.g., BYK® 345, BYK® 346, BYK® 347, BYK® 348, BYK® 349) manufactured by BYK Chemie; or combinations thereof. [0142] Examples of suitable zwitterionic (amphoteric) surfactants that may be used in the fixer fluid 12 include coco-betaine, alkyl isothionates, N,N-dimethyl-N- dodecylamine oxide, N,N-dimethyl-N-tetradecyl amine oxide (i.e. , myristamine oxide), N,N-dimethyl-N-hexadecyl amine oxide, N,N-dimethyl-N-octadecyl amine oxide, N,N- dimethyl-N-(Z-9-octadecenyl)-N-amine oxide, N-dodecyl-N,N-dimethyl glycine, lecithins, phospatidylethanolamine, phosphatidylcholine, and phosphatidylserine. [0143] The chelating agent is another example of an additive that may be included in the fixer fluid 12. When included, the chelating agent is present in an amount greater than 0 wt% active and less than or equal to 0.5 wt% active based on the total weight of the fixer fluid 12. In an example, the chelating agent is present in an amount ranging from about 0.05 wt% active to about 0.2 wt% active based on the total weight of the fixer fluid 12.

[0144] In an example, the chelating agent is selected from the group consisting of methylglycinediacetic acid, trisodium salt; 4,5-dihydroxy-1 ,3-benzenedisulfonic acid disodium salt monohydrate; ethylenediaminetetraacetic acid (EDTA); hexamethylenediamine tetra(methylene phosphonic acid), potassium salt; and combinations thereof. Methylglycinediacetic acid, trisodium salt (Na3MGDA) is commercially available as TRILON® M from BASF Corp. 4,5-dihydroxy-1 ,3- benzenedisulfonic acid disodium salt monohydrate is commercially available as TIRON™ monohydrate. Hexamethylenediamine tetra(methylene phosphonic acid), potassium salt is commercially available as DEQUEST® 2054 from Italmatch Chemicals.

[0145] Buffers are another example of an additive that may be included in the fixer fluid 12. In an example, the total amount of buffer(s) in the fixer fluid 12 ranges from 0 wt% to about 0.5 wt% (with respect to the weight of fixer fluid 12). In another example, the total amount of buffer(s) in the fixer fluid 12 is about 0.1 wt% (with respect to the weight of the fixer fluid 12). Examples of some suitable buffers include TRIS (tris(hydroxymethyl)aminomethane or Trizma), bis-tris propane, TES (2-[(2-Hydroxy- 1 ,1-bis(hydroxymethyl)ethyl)amino]ethanesulfonic acid), MES (2-ethanesulfonic acid), MOPS (3-(N-morpholino)propanesulfonic acid), HEPES (4-(2-hydroxyethyl)-1 - piperazineethanesulfonic acid), DIPSO (3-(N,N-Bis[2-hydroxyethyl]amino)-2- hydroxypropanesulfonic acid), Tricine (N-[tris(hydroxymethyl)methyl]glycine), HEPPSO (P-Hydroxy-4-(2-hydroxyethyl)-1 -piperazinepropanesulfonic acid monohydrate), POPSO (Piperazine-1 ,4-bis(2-hydroxypropanesulfonic acid) dihydrate), EPPS (4-(2- Hydroxyethyl)-1 -piperazinepropanesulfonic acid, 4-(2-Hydroxyethyl)piperazine-1 - propanesulfonic acid), TEA (triethanolamine buffer solution), Gly-Gly (Diglycine), bicine (N,N-Bis(2-hydroxyethyl)glycine), HEPBS (N-(2-Hydroxyethyl)piperazine-N'-(4- butanesulfonic acid)), TAPS ([tris(hydroxymethyl)methylamino]propanesulfonic acid), AMPD (2-amino-2-methyl-1, 3-propanediol), TABS (N-tris(Hydroxymethyl)methyl-4- aminobutanesulfonic acid), or the like.

[0146] Antimicrobial agents are another example of an additive that may be included in the fixer fluid 12. In an example, the total amount of antimicrobial agent(s) in the fixer fluid 12 ranges from about 0 wt% active to about 0.1 wt% active (with respect to the weight of the fixer fluid 12). In another example, the total amount of antimicrobial agent(s) in the fixer fluid 12 ranges from about 0.001 wt% active to about 0.1 wt% active (with respect to the weight of the fixer fluid 12). Any of the antimicrobial agent(s) described herein for the thermal inkjet ink may be used in the fixer fluid 12. [0147] The pH of the fixer fluid 12 can be less than 7. In some examples, the pH ranges from pH 1 to pH 7, from pH 3 to pH 7, from pH 4.5 to pH 7, etc. The fixer fluid 12 may have the desired pH without the incorporation of an acidic pH adjuster. If a lower pH is desired, an acidic pH adjuster (e.g., methanesulfonic acid, etc.) may be added.

[0148] In an example, the fixer fluid 12 consists of the listed components and no additional components (such as water soluble polymers, water repellent agents, etc.). In other examples, the fixer fluid 12 includes the listed components, and any other components that do not deleteriously affect the jettability of the fluid 12 via a thermal inkjet printhead may be added.

[0149] The viscosity of the fixer fluid 12 may be adjusted for a thermal inkjet printer by adjusting the co-solvent level and/or adding a viscosity modifier. For thermal inkjet printing, the viscosity of the fixer fluid 12 may be modified to range from about 1 centipoise (cP) to about 9 cP (measured at 20°C to 25°C and a shear rate of about 3,000 Hz). [0150] One specific example of the fixer fluid 12 includes the multivalent metal salt in an amount ranging from about 5 wt% to about 15 wt% based on the total weight of the fixer fluid 12; an additive selected from the group consisting of a non-ionic surfactant, a chelating agent, an antimicrobial agent, and combinations thereof; and the aqueous fixer vehicle, which includes water and an organic solvent (e.g., the co solvent).

[0151] Textile Fabrics

[0152] In the examples disclosed herein, the textile fabric 14 may be selected from the group consisting of polyester fabrics, polyester blend fabrics, cotton fabrics, cotton blend fabrics, nylon fabrics, nylon blend fabrics, silk fabrics, silk blend fabrics, wool fabrics, wool blend fabrics, and combinations thereof. In a further example, the textile fabric 14 is selected from the group consisting of cotton fabrics and cotton blend fabrics.

[0153] It is to be understood that organic textile fabrics and/or inorganic textile fabrics may be used for the textile fabric 14. Some types of fabrics that can be used include various fabrics of natural and/or synthetic fibers. It is to be understood that the polyester fabrics may be a polyester coated surface. The polyester blend fabrics may be blends of polyester and other materials (e.g., cotton, linen, etc.). In another example, the textile fabric 14 may be selected from nylons (polyamides) or other synthetic fabrics.

[0154] Example natural fiber fabrics that can be used include treated or untreated natural fabric textile substrates, e.g., wool, cotton, silk, linen, jute, flax, hemp, rayon fibers, thermoplastic aliphatic polymeric fibers derived from renewable resources (e.g. cornstarch, tapioca products, sugarcanes), etc. Example synthetic fibers used in the textile fabric/substrate 14 can include polymeric fibers such as nylon fibers, polyvinyl chloride (PVC) fibers, PVC-free fibers made of polyester, polyamide, polyimide, polyacrylic, polypropylene, polyethylene, polyurethane, polystyrene, polyaramid (e.g., KEVLAR®) polytetrafluoroethylene (TEFLON® ) (both trademarks of E.l. du Pont de Nemours and Company, Delaware), fiberglass, polytrimethylene, polycarbonate, polyethylene terephthalate, polyester terephthalate, polybutylene terephthalate, or a combination thereof. In an example, natural and synthetic fibers may be combined at ratios of 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15,

1:16, 1:17, 1:18, 1:19, 1:20, or vice versa. In some examples, the fiber can be a modified fiber from the above-listed polymers. The term “modified fiber” refers to one or both of the polymeric fiber and the fabric as a whole having undergone a chemical or physical process such as, but not limited to, copolymerization with monomers of other polymers, a chemical grafting reaction to contact a chemical functional group with one or both the polymeric fiber and a surface of the fabric, a plasma treatment, a solvent treatment, acid etching, or a biological treatment, an enzyme treatment, or antimicrobial treatment to prevent biological degradation.

[0155] In addition, the textile fabric 14 can contain additives, such as a colorant (e.g., pigments, dyes, and tints), an antistatic agent, a brightening agent, a nucleating agent, an antioxidant, a UV stabilizer, a filler, and/or a lubricant, for example.

[0156] It is to be understood that the terms “textile fabric” or “fabric substrate” do not include materials commonly known as any kind of paper (even though paper can include multiple types of natural and synthetic fibers or mixtures of both types of fibers). Fabric substrates can include textiles in filament form, textiles in the form of fabric material, or textiles in the form of fabric that has been crafted into finished articles (e.g., clothing, blankets, tablecloths, napkins, towels, bedding material, curtains, carpet, handbags, shoes, banners, signs, flags, etc.). In some examples, the fabric substrate can have a woven, knitted, non-woven, or tufted fabric structure. In one example, the fabric substrate can be a woven fabric where warp yarns and weft yarns can be mutually positioned at an angle of about 90°. This woven fabric can include fabric with a plain weave structure, fabric with twill weave structure where the twill weave produces diagonal lines on a face of the fabric, or a satin weave. In another example, the fabric substrate can be a knitted fabric with a loop structure. The loop structure can be a warp-knit fabric, a weft-knit fabric, or a combination thereof. A warp-knit fabric refers to every loop in a fabric structure that can be formed from a separate yarn mainly introduced in a longitudinal fabric direction. A weft-knit fabric refers to loops of one row of fabric that can be formed from the same yarn. In a further example, the fabric substrate can be a non-woven fabric. For example, the non-woven fabric can be a flexible fabric that can include a plurality of fibers or filaments that are one or both bonded together and interlocked together by a chemical treatment process (e.g., a solvent treatment), a mechanical treatment process (e.g., embossing), a thermal treatment process, or a combination of multiple processes.

[0157] In one example, the textile fabric 14 can have a basis weight ranging from 10 gsm to 500 gsm. In another example, the textile fabric 14 can have a basis weight ranging from 50 gsm to 400 gsm. In other examples, the textile fabric 14 can have a basis weight ranging from 100 gsm to 300 gsm, from 75 gsm to 250 gsm, from 125 gsm to 300 gsm, or from 150 gsm to 350 gsm.

[0158] The textile fabric 14 may be any color. In an example, the textile fabric is white, black, grey, etc.).

[0159] Printing Method and System

[0160] Fig. 2 depicts two examples of the printing method 100.

[0161] As shown in Fig. 2, one example the printing method 100 comprises: thermal inkjet printing an inkjet ink composition 10 onto a textile fabric 14, the inkjet ink composition 10 including: a pigment; a polymeric binder selected from the group consisting of polyurethane-based binder and an acrylic binder; a blocked polyisocyanate crosslinker including a blocking group having an initial deblocking temperature of at least 150°C; and an aqueous ink vehicle (as shown at reference numeral 102); and thermally curing the inkjet ink composition 10 on the textile fabric 14, thereby generating a print (as shown at reference numeral 104). It is to be understood that any example of the inkjet ink composition 10 and any example of the textile fabric 14 may be used in this example of the method 100.

[0162] Also as shown in Fig. 2, another example the printing method 100 includes thermally inkjet printing a fixer fluid 12 on the textile fabric 14 before thermally inkjet printing the inkjet ink composition 10, wherein the fixer fluid 12 includes a multivalent metal salt; and an aqueous fixer vehicle (as shown at reference numeral 106). It is to be understood that any example of the fixer fluid 12, any example of the inkjet ink composition 10, and any example of the textile fabric 14 may be used in this example of the method 100. [0163] Fig. 3 schematically illustrates both examples of the method 100. The textile fabric 14 may be transported through the printing system along one of the paths or routes labeled A and B.

[0164] In route A, the fixer fluid 12 is directly printed on the textile fabric 14, and the inkjet ink composition 10 is printed on the fixer fluid 12. In route B, the inkjet ink composition 10 is directly printed on the textile fabric 14.

[0165] Referring specifically to route A, a thermal inkjet applicator 18A is used to inkjet print the fixer fluid 12 on a desired area of the textile fabric 14. The thermal inkjet applicator 18A may be a cartridge or pen including, e.g., a reservoir, a droplet generator (e.g., resistor), and a plurality of nozzles. The application of the fixer fluid 12 on the textile fabric 14 forms a fixer fluid layer 12A in the desired area(s).

[0166] A thermal inkjet applicator 18B is then used to inkjet print the inkjet ink composition 10 on the fixer fluid layer 12A. The thermal inkjet applicator 18B may also be a cartridge or pen including, e.g., a reservoir, a droplet generator (e.g., resistor), and a plurality of nozzles. The applicators 18A, 18B may be separate applicators or may be a single applicator including separate reservoirs and printheads for the respective fluids 10, 12. The application of the inkjet ink composition 10 forms an ink layer 10A on the fixer fluid layer 12A.

[0167] In this example of the method 100, the fixer fluid 12 and the inkjet ink composition 10 may be applied in a single pass. As an example of single pass printing, the cartridges of a thermal inkjet printer respectively deposit each of the fluids 12, 10 during the same pass of the cartridges across the textile fabric 14. In other words, the fixer fluid 12 and the inkjet ink composition 10 are applied sequentially one immediately after the other as the thermal inkjet applicators 18A, 18B pass over the textile fabric 14. In another example of the method 100, the fixer fluid 12 and the inkjet ink composition 10 may each be applied in separate passes.

[0168] Along route A, the inkjet ink composition 10 is printed onto the fixer fluid layer 12A while the fixer fluid layer 12A is substantially wet (not fully dried or cured). Wet-on-wet printing may be desirable because less fixer fluid 12 may be applied during this process (as compared to when the fixer fluid 12 is dried prior to ink application), and because the printing workflow may be simplified without the additional drying. In an example of wet-on-wet printing, the thermal inkjet ink 10 is printed onto the fixer fluid layer 12A within a period of time ranging from about 0.01 second to about 30 seconds after the fixer fluid 12 is printed. In further examples, the thermal inkjet ink 10 is printed onto the fixer fluid layer 12A within a period of time ranging from about 0.1 second to about 20 seconds; or from about 0.2 second to about 10 seconds; or from about 0.2 second to about 5 seconds after the previously applied composition is printed. Wet-on-wet printing may be accomplished in a single pass.

[0169] The textile fabric 14 may be exposed to mild heating as the fixer fluid 12 and the thermal inkjet ink 10 are printed. As used herein, the term “mild heating” means that an air temperature in the zones where the fluids 12, 10 are dispensed ranges from about 10°C to about 90°C, such that water may be at least partially evaporated from the fixer fluid layer 12A and the ink layer 10A. Even with mild heating, the fixer fluid layer 12A is considered to be substantially wet for wet-on-wet printing.

[0170] The method 100 shown in route A of Fig. 3 then includes thermally curing the fixer fluid layer 12A and the ink layer 10A on the textile fabric 14, thereby generating a print 22. The thermal curing may be accomplished by applying heat to the textile fabric 14. Heating may be performed using any suitable heating mechanism 20, such as a heat press, oven, etc. The heat generated is sufficient to deblock the blocked polyisocyanate in the ink layer 10A, which generates active isocyanate species for crosslinking. Thermal curing is performed at or above the initial deblocking temperature of the blocked polyisocyanate in the inkjet ink 10, and for a time suitable to crosslink the deblocked polyisocyanate crosslinker with the polymeric binder in the ink layer 10A and/or with functional groups of the textile fabric 14. In an example, the thermal curing involves heating at a temperature ranging from about 160°C to about 250°C for a time ranging from about 5 seconds to about 10 minutes. In one example, thermal curing is performed at 200°C for about 60 seconds (1 minute).

[0171] Referring specifically to route B, a thermal inkjet applicator 18B is used to inkjet print the thermal inkjet ink composition 10 on a desired area of the textile fabric 14. In this example method 100, the fixer fluid 12 is not utilized. In this example, the application of the inkjet ink composition 10 forms an ink layer 10A directly on the textile fabric 14.

[0172] In this example of the method 100, the inkjet ink composition 10 may be applied in a single pass or over multiple passes.

[0173] The textile fabric 14 may be exposed to mild heating as the thermal inkjet ink 10 is printed. The mild heating of the fluid 10 may at least partially evaporate water from the ink layer 10A.

[0174] The method 100 shown in route B of Fig. 3 then includes thermally curing the ink layer 10A on the textile fabric 14, thereby generating a print 22. The thermal curing may be accomplished by applying heat to the textile fabric 14. Heating may be performed using any suitable heating mechanism 20, such as a heat press, oven, etc. The heat generated is sufficient to deblock the blocked polyisocyanate in the ink layer 10A, which generates active isocyanate species for crosslinking. Thermal curing is performed at or above the initial deblocking temperature of the blocked polyisocyanate in the inkjet ink 10, and for a time suitable to crosslink the deblocked polyisocyanate crosslinker with the polymeric binder in the ink layer 10A and/or with functional groups of the textile fabric 14. In an example, the thermal curing involves heating at a temperature ranging from about 160°C to about 250°C for a time ranging from about 5 seconds to about 10 minutes. In one example, thermal curing is performed at 200°C for about 60 seconds (1 minute).

[0175] To further illustrate the present disclosure, an example is given herein. It is to be understood that this example is provided for illustrative purposes and is not to be construed as limiting the scope of the present disclosure.

EXAMPLE

[0176] Commercially available blocked polyisocyanates were used to prepare thermal inkjet inks of various pigments and compositions. Some of the thermal inkjet inks that were formed were black inks. All the thermal black inkjet inks were formed with a base black ink (the black control example). Table 1 sets forth the base black ink formulation that was used as the control example, as well as the base formulation for the black example and comparative inks. Table 1: Base Black Ink Formulation

‘Balance varies among the control, example inks, and comparative inks depending upon the amount of blocked polyisocyanate added (if any)

[0177] The commercially available blocked polyisocyanates used to prepare the example thermal inkjet black inks were BAYBOND® XL 3674 and BAYBOND® XL 7270 (both available from Covestro). These blocked polyisocyanates have an initial deblocking temperature of about 170°C. A first thermal inkjet black ink (Example Ink K1) had the same formulation as the base black ink with the addition of BAYBOND® XL 3674 at a final concentration of 1 wt%. A second thermal inkjet black ink (Example Ink K2) had the same formulation as the base black ink with the addition of BAYBOND® XL 3674 at a final concentration of 2 wt%. A third thermal inkjet black ink (Example Ink K3) had the same formulation as the base black ink with the addition of BAYBOND® XL 7270 at a final concentration of 1 wt%. A fourth thermal inkjet black ink (Example Ink K4) had the same formulation as the base black ink with the addition of BAYBOND® XL 7270 at a final concentration of 2 wt%. Table 2 sets forth the amount of blocked polyisocyanate that is incorporated into each of the example thermal inkjet black ink formulations.

Table 2: Blocked Isocyanate in Example Black Ink Formulations

[0178] A black control example was formed with the base black ink formulation (shown in Table 1), without any added blocked polyisocyanate (see Table 3). This is referred as “Control Ink K”.

[0179] Additionally, some comparative inkjet black inks were formed with a commercially available blocked isocyanate.

[0180] The commercially available blocked polyisocyanate used to prepare the comparative thermal inkjet black inks was IMPRAFIX® 2794 (which, according to the manufacturer (Covestro) is the same as BAYHYDUR® BL 2867). This blocked polyisocyanate has an initial deblocking temp of about 140°C. Table 3 sets forth the amount of blocked polyisocyanate that is incorporated into each of the comparative thermal inkjet black ink formulations, as well and the control black ink.

Table 3: Blocked Isocyanate in Comparative Black Ink Formulations

[0181 ] Some of the thermal inkjet inks that were formed were cyan inkjet inks. All the cyan inkjet inks were formed with a base cyan ink (the cyan control example). Table 4 sets forth for the base cyan inkjet ink formulation that was used as the cyan control example, as well as the base formulation for the cyan example and comparative inks.

Table 4: Base Cyan Ink Formulation

[0182] The commercially available blocked polyisocyanates used to prepare the example thermal inkjet cyan inks were BAYBOND® XL 3674 and BAYBOND® XL 7270 (both available from Covestro). A first thermal inkjet cyan ink (Example Ink C1) had the same formulation of the base cyan ink formulation with the addition of BAYBOND® XL 3674 at a final concentration of 2 wt%. A second thermal inkjet cyan ink (Example Ink C2) had the same formulation of the base cyan ink formulation with the addition of BAYBOND® XL 7270 at a final concentration of 1 wt%. A third thermal inkjet cyan ink (Example Ink C3) had the same formulation of the base cyan ink formulation with the addition of BAYBOND® XL 7270 at a final concentration of 2 wt%. Table 5 set forth the amount of the blocked polyisocyanate incorporated into the example thermal inkjet cyan ink formulations.

Table 5: Blocked Isocyanate in Example Cyan Ink Formulations

[0183] A cyan control example was formed with the base cyan ink formulation (shown in Table 4), without any added blocked polyisocyanate (see Table 6). This is referred as “Control Ink C”.

Additionally, some comparative inkjet cyan inks were formed with a commercially available blocked isocyanate. The commercially available blocked polyisocyanate used to prepare the comparative thermal inkjet cyan inks was IMPRAFIX® 2794. Table 6 sets forth the amount of blocked polyisocyanate that is incorporated into each of the comparative thermal inkjet cyan ink formulations.

Table 6: Blocked Polyisocyanate in Comparative Cyan Ink Formulations

[0184] Next, the black and cyan control inks (Control Ink K and Control Ink C), the black and cyan example inks (K1-K4 and C1-C3), and the black and cyan comparative inks (K5, K6, C4, and C5) were tested for stability. The properties that were analyzed included the particle size, the pH, and the viscosity of the various inks.

[0185] Each control, example, and comparative black and cyan ink was stored in an accelerated storage (AS) or accelerated shelf life (ASL) environment at a temperature of 60°C for one week. The particle size for each control, example, and comparative black and cyan ink was measured before and after the inks were stored in the AS environment. The particle size for each control, example, and comparative black and cyan ink was measured in terms of the volume-weighted mean diameter (Mv) and the D95 (i.e. , 95% the population is below this value) using dynamic light scattering with a NANOTRAC® WAVE™ particle size analyzer (available from MICROTRAC™ - NIKKISO GROUP™). Then the percent change in particle size was calculated for each control, example, and comparative black and cyan ink. The particle size for each control, example, and comparative black and cyan ink before and after one week in the AS environment and the results of the particle size change are shown in Table 7. Table 7: Particle Size Results

[0186] Minimal (15% or less) to no change in particle size after storage in the AS environment indicates ink stability over time. The results shown in Table 7 indicate that the example black and cyan inks are as stable as the control inks and the comparative black and cyan inks.

[0187] The pH for each control, example, and comparative black and cyan ink was measured before and after the inks were stored in the AS environment. The pH was measured via an ACCUMET™ XL250 pH meter (available from Fisher Scientific, USA) and the inks were at ambient temperature after removal from the AS environment. Then the percent change in pH was calculated for each control, example, and comparative black and cyan ink. The pH for each control, example, and comparative black and cyan ink before and after one week in the AS environment and the results of the pH change are shown in Table 8.

[0188] The viscosity for each control, example, and comparative black and cyan ink was measured before and after the inks were stored in the AS environment. The viscosity was measured with a VISCOLITE™ viscometer at 3000 Hz and at 20°C.

Then the percent change in viscosity was calculated for each control, example, and comparative black and cyan ink. The viscosity for each control, example, and comparative black and cyan ink before and after one week in the AS environment and the results of the viscosity change are shown in Table 8.

Table 8: pH and Viscosity Results

[0189] Minimal (1 or less) to no change in pH after storage in the AS environment indicates ink stability over time. Similarly, minimal (15% or less) to no change in viscosity after storage in the AS environment also indicates ink stability over time. The results shown in Table 8 indicate that the example black and cyan inks are as or more stable as the respective control inks and the respective comparative black and cyan inks. [0190] To evaluate the jettability and kogation development in the nozzles of a printhead, the control, example, and comparative black and cyan thermal inkjet inks were then printed with thermal inkjet pens using various energy settings (firing energy, measured in m J). The drop weight (referred to herein as DW, measured in ng) was measured to produce “turn on energy” TOE curves. The term “Turn-On Energy (TOE) curve,” as used herein, refers to the drop weight of the ink as a function of firing energy. An inkjet fluid with good jettability performance also has a good TOE curve, where the fluid drop weight rapidly increases (with increased firing energy) to reach a designed drop weight for the pen architecture used; and then a steady drop weight is maintained when the firing energy exceeds the TOE. For the thermal inkjet pen used herein, the designed drop weight ranges from about 11 ng to about 14 ng. In other words, a sharp TOE curve may be correlated with good jettability performance. In contrast, an inkjet fluid with a poor TOE curve may show a slow increase in drop weight (with increased firing energy) and/or may never reach the designed drop weight for the pen architecture. A poor TOE curve may be correlated with poor jettability performance.

[0191 ] The TOE curves for all of the black inks are shown in Fig. 4A, and the TOE curves for all of the cyan inks are shown in Fig. 4B. As depicted in both Fig. 4A and Fig. 4B, the example black and example cyan inks (K1-K4 and C1-C3) exhibited good TOE curves, where the fluid drop weight rapidly increased (with increased firing energy) and then maintained a steady drop weight. The results for the example black and cyan inks were consistent with each of the control black and cyan control inks, respectively. In contrast, each of the comparative black and cyan inks (comp inks K5- K6 and C4-C5) had a worse TOE curve than the example black and cyan inks, respectively, with a slow increase in drop weight and never reaching the designed drop weight for the pen architecture.

[0192] Frequency response curves were also generated to evaluate the jettability and kogation development in the nozzles of the thermal inkjet pens. For these curves, the drop weight (measured in ng) was measured at different pen firing frequencies (in kFIz). An inkjet fluid with good jettability performance also has a good frequency response curve, where a steady fluid drop weight is maintained when the firing frequency increases up to 30 kHz. In contrast, an inkjet fluid with poor jettability performance also has a poor frequency response curve, where fluid drop weight is significantly below the targeted drop weight range when the firing frequency increases up to 30 kHz.

[0193] The frequency response curves for all of the black inks are shown in Fig. 5A, and the frequency response curves for all of the cyan inks are shown in Fig. 5B. As show Fig. 5A and Fig. 5B, both the example thermal inkjet black inks (K1-K4) and the example thermal inkjet cyan inks (C1-C3) had good frequency response curves. The example inks demonstrated reliable, jettable performance for various firing frequencies. These results were consistent with the control black and the control cyan inks (which did not include a blocked polyisocyanate). In contrast, the comparative black inks (comp inks K5-K6) and the comparative cyan inks (comp inks C4-C5) generated poor frequency response curves, demonstrating that the inks with low temperature deblocking groups did not produce reliably jettable inkjet inks.

[0194] Both of the control inks (Control Ink K and Control Ink C) exhibit desired TOE curves and frequency response curves as neither included a blocked polyisocyanate.

[0195] The results shown in Fig. 4A, Fig. 4B, Fig. 5A, and Fig. 5B indicate that significant amounts of the blocked polyisocyanate in the comparative black inks K5 and K6 and in the comparative cyan inks C4 and C5 were deblocked within the thermal inkjet pens, thus deleteriously affecting the print performance. In contrast, the example black inks (K1-K4) and example cyan inks (C1-C3) exhibited reliable print performance, which indicates that deblocking was not significant within the thermal inkjet pens. This is due to the fact that the activation energy required for driving the reaction is not achieved in the thermal inkjet pen during the short firing event, and tus the deblocking does not proceed toward completion within the thermal inkjet pen. [0196] Some of the control, example, and comparative black and cyan thermal inkjet inks were then used to generate control, example and comparative prints on fabric samples. The printing was accomplished using the thermal inkjet pens. The fabric samples used were gray cotton [100% cotton (woven)], and C1B-W1[100% cotton (knitted)]. Each of the control, example, and comparative black and cyan thermal inkjet inks prints were printed at 18.3 gsm on the respective fabrics, and then thermally cured at 200°C for 60 seconds. The generated prints and the respective ink used to generate the print are identified in Table 9.

[0197] All of the prints were analyzed for optical density using an X-rite spectrophotometer (available from Color Calibration Group). The initial optical density (initial OD) of each print (after heating or irradiation) was measured. Then, the prints were washed 5 times in a Whirlpool Washer (Model WTW5000DW) with warm water (at about 40°C) and detergent. Each print was allowed to air dry between each wash. Then, the optical density (OD after 5 washes) of each print was measured. A smaller change in optical density indicates that the color of the print has less fading. The results are shown in Table 9.

[0198] All of the prints were also analyzed for washfastness. The L*a*b* values of a color (e.g., cyan, magenta, yellow, black) before and after the 5 washes were measured. L* is lightness, a* is the color channel for color opponents green-red, and b* is the color channel for color opponents blue-yellow. The color change was then calculated using the CIEDE2000 color-difference formula (DE 2000). The CIEDE2000 color-difference formula is based on the CIELAB color space. Given a pair of color values in CIELAB space L*i ,a*i,b*i and L*2,a*₂,b*₂, the CIEDE2000 color difference between them is as follows:

A ₀₀(L^*i, aϊ, b^*; L^* ₂; L , a₂ ^*, b₂ ^* ) = AE^ = AE₀₀ (1 )

It is noted that A£₀₀is the commonly accepted notation for CIEDE2000. A smaller change in DE indicates that the print is more durable. The washfastness results are also shown in Table 9. Table 9: Optical Density and Washfastness Results

[0199] As shown in the Table 9, the comparative black and cyan prints formed with control black ink K and control black ink C (comp print 1 K and comp print 6C) had a higher change in optical density (i.e. , more fade) and worse washfastness when compared to the black example and cyan prints (prints K2-K5 and prints C7-C9), respectively. This is due to the fact that the control inks did not contain a blocked polyisocyanate for crosslinking. All of the example prints (prints K2-K5 and prints C7- C9) formed with the blocked polyisocyanate described herein (included in the example inks) had good optical density and washfastness.

[0200] It is to be understood that the ranges provided herein include the stated range and any value or sub-range within the stated range, as if the value(s) or sub range^) within the stated range were explicitly recited. For example, a range from about 1 wt% active to about 6 wt% active, should be interpreted to include not only the explicitly recited limits of from about 1 wt% active to about 6 wt% active, but also to include individual values, such as about 2.15 wt% active, about 3 wt% active, 4.2 wt% active, 5.77 wt% active, etc., and sub-ranges, such as from about 1.5 wt% active to about 5.5 wt% active, from about 3 wt% active to about 5.7 wt% active, from about 1 wt% active to about 2 wt% active, etc. Furthermore, when “about” is utilized to describe a value, this is meant to encompass minor variations (up to +/- 10%) from the stated value.

[0201 ] Reference throughout the specification to “one example”, “another example”, “an example”, and so forth, means that a particular element (e.g., feature, structure, and/or characteristic) described in connection with the example is included in at least one example described herein, and may or may not be present in other examples. In addition, it is to be understood that the described elements for any example may be combined in any suitable manner in the various examples unless the context clearly dictates otherwise.

[0202] In describing and claiming the examples disclosed herein, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise.

[0203] While several examples have been described in detail, it is to be understood that the disclosed examples may be modified. Therefore, the foregoing description is to be considered non-limiting.

Claims

What is claimed is:

1. A thermal inkjet ink composition, comprising: a pigment; a polymeric binder selected from the group consisting of polyurethane-based binder and an acrylic binder; a blocked polyisocyanate crosslinker including a blocking group having an initial deblocking temperature of at least 150°C; and an aqueous ink vehicle.

2. The thermal inkjet ink composition as defined in claim 1 wherein the blocking group of the blocked polyisocyanate crosslinker is selected from the group consisting of e-caprolactam, an alcohol, a phenol, an oxime, an imidazole or imidazoline, a triazole, uretdione, and 2-oxo-1,3-diazepane-1-carboxylate.

3. The thermal inkjet ink composition as defined in claim 2 wherein one: the blocking group is the alcohol and the alcohol is selected from the group consisting of ethanol, isopropanol, and butanol; or the blocking group is the phenol and the phenol is selected from the group consisting of phenol and o-Cresol; or the blocking group is the oxime and the oxime is benzophenone oxime; or the blocking group is the imidazole and wherein the imidazole is selected from the group consisting imidazole, 2-methylimidazole, and 2-phenylimidazole; or the blocking group is the triazole and the triazole is benzotriazole.

4. The thermal inkjet ink composition as defined in claim 1 wherein the polyurethane-based binder is selected from the group consisting of a polyester- polyurethane binder, a polyether-polyurethane binder, a polycarbonate-polyurethane binder, and combinations thereof.

5. The thermal inkjet ink composition as defined in claim 1 wherein the blocked polyisocyanate crosslinker is present in an amount ranging from about 0.2 wt% to about 5 wt% based on a total weight of the thermal inkjet ink composition.

6. The thermal inkjet ink composition as defined in claim 1 wherein the aqueous ink vehicle includes water, a co-solvent, and an additive selected from the group consisting of an anti-kogation agent, an anti-decel agent, a surfactant, an antimicrobial agent, and combinations thereof.

7. The thermal inkjet ink composition as defined in claim 1 wherein the blocked polyisocyanate crosslinker is in the form of uncoated solid particles.

8. The thermal inkjet ink composition as defined in claim 1 wherein the polymer binder is the acrylic binder.

9. A thermal inkjet textile printing kit, comprising: an inkjet ink, including: a pigment; a polymeric binder selected from the group consisting of polyurethane- based binder and an acrylic binder; an aliphatic blocked polyisocyanate crosslinker, wherein a polyisocyanate of the aliphatic blocked polyisocyanate crosslinker is selected from the group consisting of 4,4'-dicyclohexylmethane diisocyanate, hexamethylene diisocyanate trimer, hexamethylene diisocyanate biuret, isophorone diisocyanate, and isophorone diisocyanate trimer, and a blocking group of the aliphatic blocked polyisocyanate crosslinker is selected from the group consisting of e-caprolactam, ethanol, isopropanol, butanol, phenol, o- Cresol, benzophenone oxime, imidazole, 2-methylimidazole, 2-phenylimidazole, benzotriazole, uretdione, and 2-oxo-1,3-diazepane-1-carboxylate; and an aqueous ink vehicle including an anti-kogation agent.

10. The thermal inkjet textile printing kit as defined in claim 9, further comprising a fixer fluid including: a multivalent metal salt; and an aqueous fixer vehicle.

11. The thermal inkjet textile printing kit as defined in claim 9, further comprising a textile fabric selected from the group consisting of polyester fabrics, polyester blend fabrics, cotton fabrics, cotton blend fabrics, nylon fabrics, nylon blend fabrics, silk fabrics, silk blend fabrics, wool fabrics, wool blend fabrics, and combinations thereof.

12. The thermal inkjet textile printing kit as defined in claim 9 wherein inkjet ink includes: the pigment present in an amount ranging from about 3 wt% active to about 4 wt% active; the aliphatic blocked polyisocyanate crosslinker present in an amount ranging from about 1 wt% active to about 2 wt% active; and the polymeric binder present in an amount ranging from about 1 wt% active to about 6 wt% active.

13. A printing method, comprising: thermal inkjet printing an inkjet ink composition onto a textile fabric, the inkjet ink composition including: a pigment; a polymeric binder selected from the group consisting of polyurethane- based binder and an acrylic binder; a blocked polyisocyanate crosslinker including a blocking group having an initial deblocking temperature of at least 150°C; and an aqueous ink vehicle; and thermally curing the inkjet ink composition on the textile fabric, thereby generating a print.

14. The printing method as defined in claim 13 wherein thermally curing the inkjet ink composition on the textile fabric involves heating at a temperature ranging from about 160°C to about 250°C for a time ranging from about 5 seconds to about 10 minutes.

15. The printing method as defined in claim 13, further comprising thermal inkjet printing a fixer fluid on the textile fabric before thermally inkjet printing the inkjet ink composition, wherein the fixer fluid includes: a multivalent metal salt; and an aqueous vehicle.