Inkjet Ink Formulations

Abstract

The present disclosure relates to inkjet ink formulations and their use in improving a printing process and / or the resulting printed product. The present disclosure further relates to printing methods utilizing the inkjet ink formulations and printing systems comprising same.

Description

[Technical field]

[0001] The present disclosure relates to ink-jet ink formulations and their use to improve the printing process and the resulting printed product. [Background technology]

[0002] The present invention relates to ink formulations for inkjet printing systems, and more particularly to ink formulations for indirect printing systems in which an inkjet printhead is used to print an image onto the surface of an intermediate transfer member (ITM), which is then used to transfer the image to a substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] WO2013 / 132439(PCT / IB2013 / 51755) [Patent Document 2] WO2015 / 036865(PCT / IB2014 / 02395) [Patent Document 3] WO2017 / 208152(PCT / IB2017 / 053177) [Patent Document 4] WO2013 / 132418(PCT / IB2013 / 051716) [Patent Document 5] WO2019 / 012456(PCT / IB2018 / 055126) [Patent Document 6] WO2020 / 003088(PCT / IB2019 / 055288) [Patent Document 7] WO2013 / 132420(PCT / IB2013 / 051718) [Patent Document 8] WO2015 / 036906(PCT / IB2014 / 064277) [Patent Document 9] WO2020 / 136517(PCT / IB2019 / 061081) [Patent Document 10] WO2020 / 141465(PCT / IB2020 / 050001) [Patent Document 11] WO2022 / 024106(PCT / IL2021 / 050846) [Patent Document 12] PCT / IL2023 / 050117 Summary of the Invention [Problem to be solved by the invention]

[0004] Although indirect printing technology overcomes many of the problems associated with inkjet printing directly onto a substrate, there remains a need for improvements in this technology, particularly improvements in ink formulations suitable for inkjet onto the intermediate transfer member of an indirect printing system. High quality printed articles are also desired.

[0005] The following patent applications / publications to the present applicant provide potentially relevant background material and are all incorporated herein by reference in their entireties: [1]WO2013 / 132439(PCT / IB2013 / 51755); [2]WO2015 / 036865(PCT / IB2014 / 02395); [3]WO2017 / 208152(PCT / IB2017 / 053177); [4]WO2013 / 132418(PCT / IB2013 / 051716); [5]WO2019 / 012456(PCT / IB2018 / 055126); [6]WO2020 / 003088(PCT / IB2019 / 055288); [7]WO2013 / 132420(PCT / IB2013 / 051718); [8]WO2015 / 036906(PCT / IB2014 / 064277); [9]WO2020 / 136517(PCT / IB2019 / 061081);

[10] WO2020 / 141465(PCT / IB2020 / 050001);

[11] WO2022 / 024106 (PCT / IL2021 / 050846); and

[12] PCT / IL2023 / 050117

[0006] Identification of the above references herein should not be construed as implying that they are in any way relevant to the patentability of the subject matter of the present disclosure. [Means for solving the problem]

[0007] Summary of the Invention The present inventors have developed a water-based inkjet ink formulation / composition that includes at least one surfactant selected to impart to the ink formulation dynamic surface tension properties that beneficially affect the printing process and the quality of the resulting printed image.

[0008] As demonstrated herein below, the present inventors have surprisingly discovered that an inkjet ink formulation having a dynamic surface tension of about 37 mN / m to about 50 mN / m (measured at a 0.015 second bubble life-time) and a static surface tension of about 23.0 mN / m to about 25.5 mN / m (measured at a 10 second bubble life-time) favorably affects the printing process and the printed image quality and resolution.

[0009] The dynamic surface tension and static surface tension were both measured at room temperature (eg, about 22° C.) by the bubble pressure method using a Sita bubble pressure tensiometer: Model Sita online (Pro-line T15).

[0010] The inkjet ink formulation / composition of the present invention is particularly utilized in indirect printing processes. Such printing processes are detailed, for example, in published patents / applications to the applicant [1]-

[12] . Briefly, in such processes, first an aqueous ink formulation is jetted onto an intermediate transfer member, where an ink image is formed. The formed ink image is then transferred from the ITM to the final substrate. The ITM is hydrophobic (e.g., made of silicone). For good performance, it is important that the ink formulation efficiently wets the ITM. This is usually achieved by ink formulations with relatively low surface tension, e.g., less than 25 mN / m at room temperature. The inventors have found that utilizing such ink formulations is optimal for wetting the ITM, but improvements are still required for better print performance and print quality. For example, the inventors have observed a sweating effect of the ink on the nozzle plate of the print head (PH), i.e., the spreading of the ink on the nozzle plate of the PH, during printing, during automatic cleaning of the print head (PH), and also during non-printing (standby) periods. This sweating effect was mitigated when the ink formulation of the present invention was utilized in the printing process. By adjusting the dynamic surface tension of the ink formulation, it was achieved to alleviate the sweating of the ink on the PH by allowing a high surface tension in the high frequency area and reaching a standard low surface tension in the low frequency area. The adjustment of the dynamic surface tension was achieved by utilizing a specific surfactant(s) that provides an optimal dynamic surface tension profile.

[0011] Without wishing to be bound by theory, it is believed that surfactants applicable to the present invention have a low diffusion coefficient, i.e., they can move relatively slowly from high concentration regions to low concentration regions. This action results in a relatively high dynamic surface tension at higher bubble formation frequencies. Furthermore, without wishing to be bound by theory, the inventors of the present disclosure have developed inkjet ink formulations with relatively high dynamic surface tension, taking advantage of the fact that the time scale of ink spreading on a printing substrate (e.g., in a direct printing process) or on an ITM (in an indirect printing process) is much shorter than on a printhead. Thus, these ink formulations achieve similar spreading properties on a substrate or ITM as inks with low surface tension, while avoiding the downside of undesirable sweating of the nozzle plate of the printhead.

[0012] The ink formulations of the present invention, when utilized in a printing process, not only advantageously exhibit a substantial absence of sweating effects at the PH (print head), but also provide one or more of the following to the printing process: improved jetting stability over time; more usable print cycles / run (especially due to reduced ink build-up in the ink nozzles); improved print head life; easier maintenance; improved process stability; and improved print quality (e.g., improved one or more of print uniformity, ink wetting on the ITM, dot size, ink spreading characteristics, missing nozzle compensation, print head compatibility).

[0013] Thus, in one aspect, the present invention provides an aqueous inkjet ink formulation comprising: (a) a solvent containing water; (b) at least one colorant; and (c) at least one surfactant; wherein the ink formulation has a dynamic surface tension of about 37 to about 50 mN / m (measured with a bubble life of about 0.015 seconds) and a static surface tension of about 23.0 to about 25.5 mN / m (measured with a bubble life of about 10 seconds), both of which are measured at room temperature (RT, e.g., about 22° C.) using the bubble pressure method utilizing a Sita bubble pressure tensiometer: Model Sita online (Pro-line T15); and The at least one surfactant is selected to obtain the dynamic surface tension and the static surface tension.

[0014] In a further aspect thereof, the present invention provides a method for preventing and / or minimizing and / or reducing sweating of inkjet ink on a print head of a printing system (e.g. a print head used in an inkjet printing process and forming part of a printing system), said method comprising utilising (e.g. in a printing process) an aqueous inkjet ink formulation comprising: (a) a solvent containing water; (b) at least one colorant; and (c) at least one surfactant; wherein the ink formulation has a dynamic surface tension of about 37 to about 50 mN / m (measured with a bubble life of about 0.015 seconds) and a static surface tension of about 23.0 to about 25.5 mN / m (measured with a bubble life of about 10 seconds), both of which are measured at room temperature (e.g., about 22° C.) using the bubble pressure method utilizing a Sita bubble pressure tensiometer: Model Sita online (Pro-line T15); and The at least one surfactant is selected to obtain the dynamic surface tension and the static surface tension, thereby preventing and / or minimizing and / or reducing sweating of the inkjet ink on a print head of a printing system.

[0015] In another of its aspects, the present invention provides a method for preventing and / or minimizing and / or reducing sweating of inkjet ink on a print head of a printing system (e.g. a print head used in an inkjet printing process and forming part of a printing system), said method comprising utilising an aqueous inkjet ink formulation of the present invention as disclosed herein.

[0016] In a further aspect thereof, the present invention provides an aqueous inkjet ink formulation as disclosed herein for use in a method for preventing and / or minimizing and / or reducing sweating of inkjet ink on a printhead of a printing system.

[0017] Furthermore, in a further aspect thereof, the present invention provides an aqueous inkjet ink formulation as disclosed herein for use in preventing and / or minimizing and / or reducing sweating of the inkjet ink on a print head of a printing system.

[0018] In a further aspect thereof, the present invention provides a method for one or more of improving a printing process and improving the quality of the resulting printed image, said method comprising utilizing (e.g. in the printing process) an aqueous inkjet ink formulation comprising: (a) a solvent containing water; (b) at least one colorant; and (c) at least one surfactant; wherein the ink formulation has a dynamic surface tension of about 37 to about 50 mN / m (measured with a bubble life of about 0.015 seconds) and a static surface tension of about 23.0 to about 25.5 mN / m (measured with a bubble life of about 10 seconds), both of which are measured at room temperature (e.g., about 22° C.) using the bubble pressure method utilizing a Sita bubble pressure tensiometer: Model Sita online (Pro-line T15); and The at least one surfactant is selected to obtain the dynamic surface tension and the static surface tension, thereby improving one or more of the quality of the printing process and the resulting printed image.

[0019] In another of its aspects, the present invention provides a method for one or more of improving a printing process and improving the quality of the resulting printed image, the method comprising utilizing in the printing process an aqueous inkjet ink formulation as disclosed herein.

[0020] In a further aspect thereof, the present invention provides an aqueous inkjet ink formulation as disclosed herein for use in a method for one or more of improving the printing process and improving the quality of the resulting printed image.

[0021] Furthermore, in a further aspect thereof, the present invention provides an aqueous inkjet ink formulation as disclosed herein for use in one or more of improving the printing process and improving the quality of the resulting printed image.

[0022] In another of its aspects, the present invention provides an aqueous inkjet ink formulation as disclosed herein, for use in a printing process, such as described herein.

[0023] In a further aspect thereof, the present invention provides an aqueous inkjet ink formulation as disclosed herein, said formulation forming part of a printing system, for example as described herein.

[0024] In a further aspect thereof, the present invention provides a method of printing utilizing the aqueous inkjet ink formulation as disclosed herein.

[0025] Furthermore, in a further aspect of the invention, the invention provides a method of printing on a substrate, said method comprising inkjetting an ink formulation onto a print substrate by utilizing one or more print bars each comprising one or more printheads, thereby forming an ink image on said substrate, wherein the ink formulation is an aqueous inkjet ink formulation according to the present invention.

[0026] In another aspect thereof, the present invention provides a method of printing comprising: providing an intermediate transfer member having a release layer surface; ink-jetting an ink formulation onto the release layer surface by utilizing one or more print bars, each print bar comprising one or more print heads, thereby forming an ink image on the release layer surface; and transferring said ink image from the intermediate transfer member to a print substrate; wherein said ink formulation is an aqueous inkjet ink formulation according to the present invention.

[0027] Additionally, in a further aspect thereof, the present invention provides a printing system comprising an aqueous inkjet ink formulation as disclosed herein.

[0028] In another aspect thereof, the present invention provides a printing system comprising an image-forming station comprising one or more print bars, each print bar configured to hold an ink formulation and comprising one or more print heads, each of said one or more print heads configured to jet said ink formulation onto a print substrate to form an ink image on said substrate, wherein at least one of said one or more print bars is configured to hold an aqueous inkjet ink formulation according to the present invention.

[0029] In a further aspect thereof, the present invention provides a printing system comprising: an intermediate transfer member having a release layer surface; an imaging station comprising one or more print bars, each print bar configured to hold an ink formulation, and comprising one or more print heads, each of the one or more print heads configured to jet the ink formulation onto the release layer surface to form an ink image thereon, wherein at least one of the one or more print bars is configured to hold an aqueous ink-jet ink formulation according to the present invention; and A transfer station for transferring the ink image from the intermediate transfer member to a print substrate.

[0030] The present invention in a still further aspect provides a printing system and process substantially as described herein.

[0031] Additionally, in a further aspect thereof, the present invention provides an aqueous inkjet ink formulation substantially as described herein.

[0032] In another of its aspects, the present invention provides an aqueous inkjet ink formulation having the dynamic and static surface tensions as illustrated and described herein, e.g., in the figures.

[0033] BRIEF DESCRIPTION OF THE DRAWINGS In order to better understand the subject matter disclosed herein and to illustrate how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0034] [Figure 1] FIG. 1 is a schematic side view of a printing system (eg, a digital printing system) according to some embodiments of the present invention. [Figure 2A] 2A-2B show the dynamic surface tension profiles (time scale) of several ink formulations not according to the present invention and ink formulations according to several embodiments of the present invention. [Figure 2B]2A-2B show the dynamic surface tension profiles (time scale) of several ink formulations not according to the present invention and ink formulations according to several embodiments of the present invention. [Diagram 3] FIG. 3 shows the dynamic surface tension profiles (log scale) of several ink formulations not according to the present invention and ink formulations according to some embodiments of the present invention. [Figure 4] 4A-4D show images of the nozzle plate (top panel) and the resulting printed substrate (bottom panel) when used with ink formulations not according to the present invention and ink formulations according to some embodiments of the present invention. [Figure 5A] 5A-5B show ink contact angle (CA) measurements at 80° C. for hydrophobic ITMs coated with treatment formulations, and show several ink formulations not according to the present invention and several embodiments of the present invention. [Figure 5B] 5A-5B show ink contact angle (CA) measurements at 80° C. for hydrophobic ITMs coated with treatment formulations, and show several ink formulations not according to the present invention and several embodiments of the present invention. [Figure 6A] 6A-6B show dynamic surface tension profiles (time scale) of ink formulations not according to the present invention and ink formulations according to some embodiments of the present invention. [Figure 6B] 6A-6B show dynamic surface tension profiles (time scale) of ink formulations not according to the present invention and ink formulations according to some embodiments of the present invention. [Figure 7] FIG. 7 shows the dynamic surface tension profiles (log scale) of ink formulations not according to the present invention and ink formulations according to some embodiments of the present invention. [Figure 8] FIG. 8 shows the dynamic surface tension profile (time scale) of ink formulations according to some embodiments of the present invention. [Figure 9] FIG. 9 shows the dynamic surface tension profile (log scale) of ink formulations according to some embodiments of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] Detailed Description of the Invention In one aspect, the present invention provides an aqueous inkjet ink formulation comprising: (a) a solvent containing water; (b) at least one colorant; and (c) at least one surfactant; wherein the ink formulation has a dynamic surface tension of about 37 to about 50 mN / m (measured with a bubble life of about 0.015 seconds) and a static surface tension of about 23.0 to about 25.5 mN / m (measured with a bubble life of about 10 seconds), both of which are measured at room temperature (e.g., about 22° C.) using the bubble pressure method utilizing a Sita bubble pressure tensiometer: Model Sita online (Pro-line T15); and The at least one surfactant is selected to obtain the dynamic surface tension and the static surface tension.

[0036] Various embodiments are detailed herein in relation to the aforementioned aspects of the invention. It should be noted that one or more of the embodiments detailed in relation to the aqueous inkjet ink formulation of the invention may also be applied mutatis mutandis to other aspects of the invention, such as methods, processes, uses and systems.

[0037] It is further noted that various means of measuring dynamic and static surface tension are known to those skilled in the art, and therefore the present disclosure should not be considered limited to the specific Sita bubble pressure tensiometer, and other corresponding measurements are equivalent and within the scope of the present invention. It is noted that those skilled in the art are familiar with other measurement means and conversions between the specific dynamic and static surface tensions described above and the equivalent values ​​measured by other measurement means.

[0038] Sometimes the ink formulations of the present invention may be referred to as "high dynamic surface tension ink formulations", e.g., having a dynamic surface tension of about 37 to about 50 mN / m, measured at room temperature by Model Sita online (Pro-line T15). The ink formulations of the present invention have a higher dynamic surface tension than the static surface tension measured at the same temperature.

[0039] In some embodiments of the present invention, the dynamic surface tension of the ink formulation is from about 37 to about 50 mN / m, inclusive (measured with a bubble life of about 0.015 seconds at RT). Any value within the above range is within the scope of the present invention, for example, 37.0, 37.1, 37.2, 37.3, 37.4, 37.5, 37.6, 37.7, 37.8, 37.9, 38.0, 38.1, 38.2, 38.3, 38.4, 38.5, 38.6, 38.7, 38.8, 38.9, 39.0, 39.1, 39.2, 39.3, 39.4, 39.5, 39.6, 39.7, 39.8, 39.9, 39.10, 39.11, 39.12, 39.13, 39.14, 39.15, 39.16, 39.17, 39.18, 39.19 ... .9, 40.0, 40.1, 40.2, 40.3, 40.4, 40.5, 40.6, 40.7, 40.8, 40.9, 41.0, 41.1, 41.2, 41.3, 41.4, 41.5, 41.6, 41.7, 41.8, 41.9, 42.0, 42.1, 42.2, 42.3, 42.4, 42.5, 42.6, 42.7, 42.8, 42.9, 43.0, 43.1, 43.2, 43.3 ,43.4,43.5,43.6,43.7,43.8,43.9,44.0,44.1,44.2,44.3,44.4,44.5,44.6,44.7,44.8,44.9,45.0,45.1,45.2,45.3,45.4,45.5,45.6,45.7,45.8,45.9,46.0,46.1,46.2,46.3,46.4,46.5,46.6,46.7,4 6.8, 46.9, 47.0, 47.1, 47.2, 47.3, 47.4, 47.5, 47.6, 47.7, 47.8, 47.9, 48.0, 48.1, 48.2, 48.3, 48.4, 48.5, 48.6, 48.7, 48.8, 48.9, 49.0, 49.1, 49.2, 49.3, 49.4, 49.5, 49.6, 49.7, 49.8, 49.9 and 50.0 mN / m.

[0040] In some embodiments of the present invention, the static surface tension of the ink formulation is from about 23.0 to about 25.5 mN / m, inclusive (measured at room temperature (RT) for about 10 seconds bubble life). Any value within the above range is within the scope of the present invention, such as 23.0, 23.1, 23.2, 23.3, 23.4, 23.5, 23.6, 23.7, 23.8, 23.9, 24.0, 24.1, 24.2, 24.3, 24.4, 24.5, 24.6, 24.7, 24.8, 24.9, 25.0, 25.1, 25.2, 25.3, 25.4, and 25.5 mN / m.

[0041] In some embodiments of the present invention, the static surface tension of the ink formulation is from about 23.0 to about 25.5 mN / m, inclusive (measured using a standard liquid tensiometer, Kruss force tensiometer (model K20) at a frequency of 5 Hz and RT). Any value within the above range is within the scope of the present invention, such as 23.0, 23.1, 23.2, 23.3, 23.4, 23.5, 23.6, 23.7, 23.8, 23.9, 24.0, 24.1, 24.2, 24.3, 24.4, 24.5, 24.6, 24.7, 24.8, 24.9, 25.0, 25.1, 25.2, 25.3, 25.4, and 25.5 mN / m.

[0042] In some embodiments of the present invention, the static surface tension of the ink formulation is from about 23.6 to about 24.7 mN / m, inclusive (measured with a bubble life of about 10 seconds at RT).

[0043] In some embodiments of the present invention, the static surface tension of the ink formulation is further measured using a standard liquid tensiometer, Kruss force tensiometer (K20 model), at a frequency of 5 Hz and RT.

[0044] In some embodiments of the present invention, the static surface tension of the ink formulation is from about 23.8 to about 24.5 mN / m, inclusive (measured using a standard liquid tensiometer, Kruss force tensiometer (model K20), at a frequency of 5 Hz and RT).

[0045] In some embodiments of the present invention, the dynamic surface tension of the ink formulation is as exemplified herein.

[0046] In some embodiments of the present invention, the static surface tension of the ink formulation is as exemplified herein.

[0047] In some embodiments, the surfactant is a non-ionic surfactant.

[0048] In some embodiments, the surfactant is an anionic surfactant.

[0049] In some embodiments of the present invention, the at least one surfactant is a first type of surfactant and / or a second type of surfactant.

[0050] In some embodiments of the present invention, the ink formulations of the present invention comprise at least one surfactant of a first type and / or at least one surfactant of a second type.

[0051] In some embodiments of the present invention, the at least one surfactant is a first type of surfactant.

[0052] In some embodiments of the present invention, the first type of surfactant is a silicone surfactant.

[0053] In some embodiments of the present invention, the silicone surfactant may be a siloxane or a siloxane copolymer, such as a polyether siloxane copolymer.

[0054] In some embodiments of the present invention, the silicone surfactant may be a polyether-modified siloxane surfactant. For this purpose, the term modified contemplates a siloxane in which the silicone base structure has been chemically modified by the addition of one or more polyether side chains (e.g., polyethylene glycol, PEG). In some embodiments, the polyether may be composed of ethylene oxide (EO) units, propylene oxide (PO) units, or any combination thereof. In some embodiments, the polyether may be composed of ethylene oxide units. In some embodiments, the polyether may be composed of propylene oxide units. In some embodiments, the polyether may be composed of ethylene oxide units and propylene oxide units.

[0055] In some embodiments of the present invention, the silicone surfactant may be a polyether-modified polydimethylsiloxane surfactant. For this purpose, the term modified contemplates a siloxane in which the silicone base structure has been chemically modified by the addition of one or more polyether side chains (e.g., polyethylene glycol, PEG). In some embodiments, the polyether may be composed of ethylene oxide (EO) units, propylene oxide (PO) units, or any combination thereof. In some embodiments, the polyether may be composed of ethylene oxide units. In some embodiments, the polyether may be composed of propylene oxide units. In some embodiments, the polyether may be composed of ethylene oxide units and propylene oxide units.

[0056] In some embodiments of the present invention, the silicone surfactant is selected from the group consisting of Tego 4100, Byk349, BYK348, BYK-3456, BYK-3455, and any combination thereof.

[0057] In some embodiments of the present invention, the silicone surfactant is selected from the group consisting of Byk349, BYK348, BYK-3455, and BYK-3456, and any combination thereof.

[0058] In some embodiments of the present invention, the silicone surfactant is a siloxane-based gemini surfactant, such as Tego 4100 (CAS number 134180-76-0, oxirane, 2-methyl-, polymer with oxirane, containing mono[3-[1,3,3,3-tetramethyl-1-[(trimethylsilyl)oxy]-1-disiloxanyl]propyl]ether).

[0059] In some embodiments of the present invention, the silicone surfactant is a polyether modified siloxane selected from the group consisting of Byk349, BYK348, BYK-3455, and any combination thereof.

[0060] In some embodiments of the present invention, the silicone surfactant is a polyether modified siloxane selected from the group consisting of Byk349, BYK348, and BYK-3455.

[0061] In some embodiments of the present invention, the silicone surfactant is a polyether modified polydimethylsiloxane, such as BYK-3456.

[0062] In some embodiments of the present invention, the silicone surfactant is Byk349 (a polyether modified siloxane).

[0063] In some embodiments of the present invention, the silicone surfactant is BYK348 (a polyether modified siloxane).

[0064] In some embodiments of the present invention, the silicone surfactant is BYK-3455 (a polyether modified siloxane).

[0065] In some embodiments of the present invention, the silicone surfactant is BYK-3456 (a polyether modified polydimethylsiloxane).

[0066] In some embodiments, polyether modified polydimethylsiloxanes, such as BYK-3456 silicone surfactants, can be active simultaneously at the interface with the substrate and at the surface, i.e., have a swimming depth capable of swimming at various depths, either against air (thus affecting levelling) or deeper (thus affecting wettability).

[0067] Without wishing to be bound by theory, the selection of the surfactant of the present invention, i.e., at least one surfactant that imparts specific dynamic and static surface tension properties to the ink composition of the present invention, may be determined by one or more of the chemical nature and molecular weight of the surfactant. Applicable surfactants are those that slowly emerge on the surface of the ink droplets so as to impart specific dynamic surface tension properties to the ink.

[0068] In some embodiments, at least one surfactant is of sufficiently high molecular weight to provide particular dynamic and static surface tension properties to the ink compositions of the present invention.

[0069] In some embodiments, at least one surfactant is a chemical structure composed of a plurality of repeating units, e.g., monomeric units, where the number of repeating units is sufficiently high to provide the ink compositions of the present invention with their particular dynamic and static surface tension properties.

[0070] In some embodiments, at least one surfactant is of a chemical structure composed of a plurality of repeating units, e.g., monomeric units, which may be modified, e.g., chemically modified, with one or more side chains, and the number of modified repeating units is sufficiently high to provide the ink compositions of the present invention with their particular dynamic and static surface tension properties.

[0071] In some embodiments, at least one silicone surfactant is composed of a plurality of repeating units (e.g., siloxane units), where the number of repeating units is sufficiently high to provide the ink compositions of the present invention with their particular dynamic and static surface tension properties.

[0072] In some embodiments, at least one silicone surfactant is of a chemical structure composed of multiple repeating units, e.g., siloxane units, which may be modified, for example, by one or more polyether side chains (e.g., polyethylene glycol, PEG), and the number of modified repeating units is sufficiently high to provide the ink compositions of the present invention with their particular dynamic and static surface tension properties.

[0073] In some embodiments, at least one surfactant is of a chemical structure composed of multiple repeat units that may be modified with one or more side chains (e.g., polyether side chains such as PEG), and the ratio of the number of unmodified repeat units to the number of modified repeat units is selected to impart to the ink compositions of the present invention their particular dynamic and static surface tension properties.

[0074] In some embodiments, at least one silicone surfactant is of a chemical structure composed of multiple repeat units that may be modified with one or more side chains (e.g., polyether side chains such as PEG), and the ratio of the number of unmodified repeat units to the number of modified repeat units is selected to provide the ink compositions of the present invention with their particular dynamic and static surface tension properties.

[0075] In some embodiments, the at least one silicone surfactant is of a chemical structure composed of a plurality of repeating siloxane units which may be modified by one or more side chains, such as polyether side chains (polyethylene glycol, PEG, etc.), and the ratio of the number of unmodified repeating siloxane units to the number of modified repeating siloxane units is selected to provide the ink compositions of the present invention with their particular dynamic and static surface tension properties.

[0076] In some embodiments of the present invention, the silicone surfactant is a polyether modified siloxane having multiple numbers of repeating units, thereby imparting particular dynamic and static surface tension properties to the ink compositions of the present invention.

[0077] In some embodiments of the present invention, the silicone surfactants are polyether modified siloxanes having multiple modified repeat unit numbers, thereby imparting their particular dynamic and static surface tension properties to the ink compositions of the present invention.

[0078] In some embodiments of the present invention, the silicone surfactants are polyether-modified siloxanes having a number of modified repeat units (e.g., modified with polyether side chains such as polyethylene glycol, PEG) and the ratio of the number of unmodified siloxane units to the number of modified repeat units (e.g., PEG-modified siloxane units) is selected to provide the ink compositions of the present invention with their particular dynamic and static surface tension properties.

[0079] In some embodiments of the present invention, the silicone surfactants are polyether modified polydimethylsiloxanes having multiple numbers of repeating units, thereby imparting their particular dynamic and static surface tension properties to the ink compositions of the present invention.

[0080] In some embodiments of the present invention, the silicone surfactants are polyether modified polydimethylsiloxanes having multiple modified repeat unit numbers, thereby imparting their particular dynamic and static surface tension properties to the ink compositions of the present invention.

[0081] In some embodiments of the present invention, the silicone surfactant is a polyether-modified polydimethylsiloxane having a number of modified repeat units (e.g., modified with polyether side chains such as polyethylene glycol, PEG), and the ratio of the number of unmodified siloxane units to the number of modified repeat units (e.g., PEG-modified siloxane units) is selected to provide the ink compositions of the present invention with their particular dynamic and static surface tension properties.

[0082] In some embodiments, at least one surfactant is of a chemical structure comprised of at least about 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or about 20 repeating units.

[0083] In some embodiments, at least one surfactant is of a chemical structure comprised of at least about 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or about 20 chemically modified repeating units (e.g., modified with polyether side chains such as polyethylene glycol, PEG).

[0084] In some embodiments, at least one surfactant is a polyether-modified siloxane having at least about 4 repeat units.

[0085] In some embodiments, at least one surfactant is a polyether-modified siloxane having at least about 4 modified repeat units.

[0086] In some embodiments, at least one surfactant has at least about 4 polyether-modified repeat units.

[0087] In some embodiments, at least one surfactant is a polyether-modified siloxane having from about 4 to about 20 repeat units, inclusive.

[0088] In some embodiments, at least one surfactant is a polyether-modified siloxane having at least about 20 repeat units.

[0089] In some embodiments, at least one surfactant is a polyether-modified siloxane having from about 4 to about 20 (inclusive) modified repeat units.

[0090] In some embodiments, at least one surfactant is a polyether-modified siloxane having at least about 20 modified repeat units.

[0091] In some embodiments, at least one surfactant is a polyether-modified polydimethylsiloxane having at least about 4 repeat units.

[0092] In some embodiments, at least one surfactant is a polyether-modified polydimethylsiloxane having at least about 4 modified repeat units.

[0093] In some embodiments, at least one surfactant is a polyether-modified polydimethylsiloxane having at least about 4 polyether-modified repeat units.

[0094] In some embodiments, at least one surfactant is a polyether-modified polydimethylsiloxane having from about 4 to about 20 repeat units, inclusive.

[0095] In some embodiments, at least one surfactant is a polyether-modified polydimethylsiloxane having at least about 20 repeat units.

[0096] In some embodiments, at least one surfactant is a polyether-modified polydimethylsiloxane having from about 4 to about 20 (inclusive) modified repeat units.

[0097] In some embodiments, at least one surfactant is a polyether-modified polydimethylsiloxane having at least about 20 modified repeat units.

[0098] In some embodiments, at least one surfactant is a polyether-modified siloxane having at least about 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or about 20 repeat units.

[0099] In some embodiments, at least one surfactant is a polyether-modified siloxane having at least about 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or about 20 chemically modified repeat units (e.g., modified with polyether side chains such as polyethylene glycol, PEG).

[0100] In some embodiments, at least one surfactant is a polyether-modified polydimethylsiloxane having at least about 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or about 20 repeat units.

[0101] In some embodiments, at least one surfactant is a polyether-modified polydimethylsiloxane having at least about 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or about 20 chemically modified repeat units (e.g., modified with polyether side chains such as polyethylene glycol, PEG).

[0102] In some embodiments of the present invention, the silicone surfactant is not one or more of Tego 240, Tego 280, and Tego 270. Without wishing to be bound by theory, the inventors believe that the number of siloxane repeat units (modified or not) in these surfactants, which affects the molecular weight of these surfactants, is insufficient to provide these surfactants with the ability to impart certain dynamic and static surface tension properties to the ink compositions of the present invention.

[0103] In some embodiments of the invention, the silicone surfactant is not Tego 240 [Evonik, polyether modified trisiloxane, CAS No. 122-20-3 (2-propanol, 1,1',1''-nitrilotris<0.05%) and CAS No. 614-100-2 (Poly(oxy-1,2-ethanediyl), a-[3-[1,3,3,3-tetramethyl-1-[(trimethylsilyl)oxy]disiloxanyl]propyl]-w-hydroxy, 75-85%)].

[0104] In some embodiments of the invention, the silicone surfactant is not Tego280 (CAS number 68938-54-5, Evonik, polyether modified siloxanes, including: ethers of siloxanes and silicones, di-Me, 3-hydroxypropyl Me, polyethylene glycol monoMe-ethers, 75-100%).

[0105] In some embodiments of the invention, the silicone surfactant is not Tego 270 (CAS number 68938-54-5, Evonik, polyether modified siloxane, including: ethers of siloxanes and silicones, di-Me, 3-hydroxypropyl Me, polyethylene glycol monoMe-ether, 75-90%).

[0106] In some embodiments of the present invention, the silicone surfactant is one or more of at least one polyether-modified siloxane surfactant and at least one polyether-modified polydimethylsiloxane.

[0107] In some embodiments of the present invention, the silicone surfactant is one or more of at least one polyether-modified siloxane surfactant, at least one polyether-modified polydimethylsiloxane, and at least one siloxane-based gemini surfactant.

[0108] In some embodiments, the siloxane-based gemini surfactant comprises a polymer having an oxirane, 2-methyl-, mono[3-[1,3,3,3-tetramethyl-1-[(trimethylsilyl)oxy]-1-disiloxanyl]propyl]ether.

[0109] In some embodiments of the present invention, the silicone surfactant is selected from the group consisting of polyether modified polydimethylsiloxanes, polyether modified siloxanes, siloxane based gemini surfactants, and any combination thereof.

[0110] In some embodiments of the present invention, at least one surfactant is a second type of surfactant.

[0111] In some embodiments of the present invention, the second type of surfactant is a non-silicone surfactant.

[0112] In some embodiments of the present invention, the non-silicone surfactant is a mixture of an ethoxylated acetylenic diol and dioctyl sodium sulfosuccinate in a solvent.

[0113] In some embodiments of the invention, the non-silicone surfactant is Surfynol PSA 336 [Evonic, CAS No. 577-11-7 (Butanedioic acid, sulfo-1,4-bis(2-ethylhexyl)ester, sodium salt, 20-50%) and CAS No. 9014-85-1 (Ethoxylated 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 20-50%), which is a mixture of ethoxylated acetylenic diol and dioctyl sodium sulfosuccinate in a solvent].

[0114] In some embodiments of the present invention, the at least one surfactant is a first type of surfactant that is a silicone surfactant, and the formulation optionally further comprises at least one surfactant of a second type that is a non-silicone surfactant.

[0115] In some embodiments of the present invention, the at least one surfactant is a first type of surfactant that is a silicone surfactant, and the formulation further comprises at least one surfactant of a second type that is a non-silicone surfactant.

[0116] In some embodiments of the present invention, the at least one surfactant is a second type of surfactant that is a non-silicone surfactant, and the formulation optionally further comprises at least one surfactant of a first type that is a silicone surfactant.

[0117] In some embodiments of the invention, the at least one surfactant is a second type of surfactant that is a non-silicone surfactant, and the formulation further comprises at least one surfactant of a first type that is a silicone surfactant.

[0118] In some embodiments, the ink formulation of the present invention comprises at least one surfactant of a first type that is a silicone surfactant selected from the group consisting of polyether modified polydimethylsiloxanes, polyether modified siloxanes, siloxane based gemini surfactants, and any combination thereof, and the ink formulation optionally further comprises at least one surfactant of a second type that is a mixture of an ethoxylated acetylenic diol and dioctyl sodium sulfosuccinate in a solvent.

[0119] In some embodiments, the ink formulation of the present invention comprises at least one surfactant of a second type that is a mixture of ethoxylated acetylenic diol and dioctyl sodium sulfosuccinate in a solvent, and the ink formulation optionally further comprises at least one surfactant of a first type that is a silicone surfactant selected from the group consisting of polyether-modified polydimethylsiloxanes, polyether-modified siloxanes, siloxane-based gemini surfactants, and any combination thereof.

[0120] In some embodiments, the ink formulation of the present invention comprises at least one surfactant of a first type that is one or more of at least one polyether-modified siloxane surfactant and at least one polyether-modified polydimethylsiloxane, and at least one surfactant of a second type that is a mixture of an ethoxylated acetylenic diol and dioctyl sodium sulfosuccinate in a solvent.

[0121] In some embodiments, the ink formulation of the present invention comprises at least one surfactant of a first type that is one or more of at least one polyether-modified siloxane surfactant, at least one polyether-modified polydimethylsiloxane, and at least one siloxane-based gemini surfactant, and at least one surfactant of a second type that is a mixture of an ethoxylated acetylenic diol and dioctyl sodium sulfosuccinate in a solvent.

[0122] In some embodiments, the ink formulations of the present invention include at least one surfactant of a first type that is at least one polyether-modified siloxane surfactant and at least one surfactant of a second type that is a mixture of an ethoxylated acetylenic diol and dioctyl sodium sulfosuccinate in a solvent.

[0123] In some embodiments, the ink formulations of the present invention include at least one surfactant of a first type that is at least one polyether-modified polydimethylsiloxane and at least one surfactant of a second type that is a mixture of an ethoxylated acetylenic diol and dioctyl sodium sulfosuccinate in a solvent.

[0124] In some embodiments, the ink formulations of the present invention include at least one surfactant of a first type that is at least one siloxane-based gemini surfactant and at least one surfactant of a second type that is a mixture of an ethoxylated acetylenic diol and dioctyl sodium sulfosuccinate in a solvent.

[0125] In some embodiments, the ink formulation of the present invention comprises at least one surfactant that is a first type of surfactant, i.e., a silicone surfactant, selected from the group consisting of Tego 4100, Byk349, BYK348, BYK-3456, BYK-3455, and any combination thereof, and the ink formulation optionally further comprises at least one surfactant that is a second type of surfactant, i.e., a non-silicone surfactant, where the non-silicone surfactant is Surfynol PSA.

[0126] In some embodiments, the ink formulation of the present invention comprises at least one surfactant that is a first type of surfactant, i.e., a silicone surfactant, selected from the group consisting of Byk349, BYK348, BYK-3456, BYK-3455, and any combination thereof, and the ink formulation optionally further comprises at least one surfactant that is a second type of surfactant, i.e., a non-silicone surfactant, wherein the non-silicone surfactant is Surfynol PSA.

[0127] In some embodiments, the ink formulations of the present invention include at least one surfactant of a first type that is BYK-3456 and at least one surfactant of a second type that is Surfynol PSA.

[0128] In some embodiments, at least one surfactant is present in the aqueous inkjet ink formulation according to the present invention in a concentration of about 0.1% w / w to about 3.0% w / w, inclusive. Any value within the above concentration range is within the scope of the present invention, such as 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, and 3.0% w / w.

[0129] In some embodiments, at least one surfactant is present in the aqueous inkjet ink formulation according to the present invention at a concentration of about 0.5% w / w to about 3.0% w / w, inclusive.

[0130] In some embodiments, at least one surfactant is present in the aqueous inkjet ink formulation according to the present invention at a concentration of about 0.5% w / w to about 2.5% w / w, inclusive.

[0131] In some embodiments, the at least one surfactant is a first type of surfactant, i.e., a silicone surfactant, and is present in the aqueous inkjet ink formulation according to the present invention at a concentration of about 0.1 w / w% to about 3.0 w / w%, inclusive. Any value within the above concentration range is within the scope of the present invention, such as 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, and 3.0 w / w%. Sometimes the first type of surfactant, i.e. the silicone surfactant, is present in the aqueous inkjet ink formulation according to the present invention at a concentration of from about 0.5 w / w% to about 3.0 w / w% (inclusive), sometimes at a concentration of from about 1.0 w / w% to about 3.0 w / w% (inclusive), and further sometimes at a concentration of from about 0.5 w / w% to about 2.5 w / w% (inclusive).

[0132] In some embodiments, the at least one surfactant is a second type of surfactant, i.e., a non-silicone surfactant, and is present in the aqueous inkjet ink formulation according to the present invention at a concentration of about 0.1 w / w% to about 0.5 w / w%, inclusive. Any value within the above concentration range is within the scope of the present invention, for example, 0.1, 0.2, 0.3, 0.4 and 0.5 w / w%.

[0133] In some embodiments, the at least one surfactant is a first type of surfactant, i.e., a silicone surfactant, present in the aqueous inkjet ink formulation according to the present invention at a concentration of from about 0.1 w / w % to about 3.0 w / w %, inclusive, sometimes at a concentration of from about 1.0 w / w % to about 3.0 w / w %, inclusive, and even sometimes at a concentration of from about 0.5 w / w % to about 2.5 w / w %, inclusive, and a second type of surfactant, i.e., a non-silicone surfactant, optionally present in the aqueous inkjet ink formulation according to the present invention at a concentration of from about 0.0 w / w % to about 0.5 w / w %, inclusive.

[0134] In some embodiments, ink formulations according to the present invention comprise at least one surfactant of a first type (i.e., a silicone surfactant) and at least one surfactant of a second type (i.e., a non-silicone surfactant), wherein the first type and the second type of surfactant are present in the ink formulation in a ratio of about 4:1 to about 200:1, inclusive. Any value within the above ratio range is within the scope of the present invention.

[0135] In some embodiments, the total surfactant content in the ink formulation of the present invention is about 4.0 w / w%, sometimes about 3.5%, sometimes about 3.0%, and still more sometimes about 2.5%.

[0136] In some embodiments of the present invention, the at least one surfactant is a first type of surfactant selected to obtain the dynamic and static surface tension of the ink formulation as disclosed herein.

[0137] In some embodiments of the present invention, the at least one surfactant is a second type of surfactant selected to obtain the dynamic and static surface tension of the ink formulation as disclosed herein.

[0138] In some embodiments of the present invention, the ink formulations of the present invention comprise a first and a second type of surfactant, the combination of which is selected to obtain the dynamic and static surface tension of the ink formulation as disclosed herein.

[0139] In some embodiments, the surfactants of the present invention are completely soluble in the aqueous ink formulations of the present invention.

[0140] In some embodiments, the at least one surfactant and its content in the ink formulation according to the present invention is as disclosed and exemplified herein.

[0141] In some embodiments, the ink formulation according to the present invention is as disclosed and exemplified herein.

[0142] The water-based inkjet ink formulations of the present invention are aqueous inks. In some embodiments, water comprises at least about 30% w / w of the formulation, sometimes at least about 40% w / w, and sometimes at least about 50% w / w or more.

[0143] In some embodiments according to the present invention, water comprises from about 30.0 w / w% to about 65.0 w / w%, between 30.0 w / w% and 65.0 w / w%, inclusive, of the ink formulation. Any value within the above concentration ranges is within the scope of the present invention, for example, 30.0, 31.0, 32.0, 33.0, 34.0, 35.0, 36.0, 37.0, 38.0, 39.0, 40.0, 41.0, 42.0, 43.0, 44.0, 45.0, 46.0, 47.0, 48.0, 49.0, 50.0, 51.0, 52.0, 53.0, 54.0, 55.0, 56.0, 57.0, 58.0, 59.0, 60.0, 61.0, 62.0, 63.0, 64.0 and 65.0 w / w%.

[0144] In some embodiments according to the present invention, water comprises from about 45.0 w / w% to about 65.0 w / w%, 45.0 w / w% to 65.0 w / w%, inclusive, of the ink formulation.

[0145] In some embodiments, the aqueous inkjet ink formulation of the present invention may further comprise at least one co-solvent, such as a humectant.

[0146] In some embodiments, the aqueous inkjet ink formulations of the present invention may optionally further comprise one or more water-miscible co-solvents.

[0147] In some embodiments, the ink formulation according to the present invention may further comprise at least one co-solvent. In some embodiments, the co-solvent is miscible with water. In some embodiments, the co-solvent is miscible with water at at least one particular temperature in the range of 20° C. to 60° C., whereby the solvent is a single-phase solvent. In some embodiments, the co-solvent is selected to provide a single-phase solvent with reduced vapor pressure relative to water at at least one particular temperature in the range of 20° C. to 60° C. In some embodiments, the co-solvent is selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol, glycerol, PEG400, N-methylpyrrolidone, and mixtures thereof. In some embodiments, the co-solvent is selected from the group consisting of dipropylene glycol, tripropylene glycol methyl ether, DMSO, and mixtures thereof. In some embodiments, the co-solvent comprises at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, or at least 40% (w / w) of the formulation. In some embodiments, the co-solvent comprises 40% or less, 35% or less, 30% or less, 25% or less, 20% or less, 15% or less, 10% or less, or 5% or less (w / w) of the formulation. In some embodiments, the ratio of co-solvent to water by weight is in the range of 0.1:1 to 1:1. Any value in the above ratio range is within the scope of the present invention.

[0148] In some embodiments according to the present invention, the co-solvent is present in the aqueous inkjet ink formulation according to the present invention in a concentration of from about 12.0 w / w% to about 25.0 w / w%, from 12.0 w / w% to 25.0 w / w%, inclusive. Any value within the above concentration range is within the scope of the present invention, such as 12.0, 12.5, 13.0, 13.5, 14.0, 14.5, 15.0, 15.5, 16.0, 16.5, 17.0, 17.5, 18.0, 18.5, 19.0, 19.5, 20.0, 20.5, 21.0, 21.5, 22.0, 22.5, 23.0, 23.5, 24.0, 24.5, and 25.0 w / w%.

[0149] In some embodiments, the co-solvent is propylene glycol.

[0150] As used herein, the terms "colorant" and "coloring agent," or any linguistic variations thereof, are interchangeable.

[0151] In some embodiments, the colorant comprises at least about 1.0 w / w% of the ink formulation.

[0152] In some embodiments, the colorant comprises a pigment or a mixture of pigments.

[0153] In some embodiments according to the present invention, the at least one colorant is present in the aqueous inkjet ink formulation according to the present invention at a concentration of from about 0.1 w / w% to about 5.0 w / w%, from 0.1 w / w% to 5.0 w / w%, inclusive. Any value within the above concentration ranges is within the scope of the present invention, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9 and 5.0 w / w%.

[0154] In some embodiments according to the present invention, the total concentration of the colorant(s) in the aqueous inkjet ink formulation according to the present invention is from about 0.1 w / w% to about 5.0 w / w%, from 0.1 w / w% to 5.0 w / w%, inclusive. Any value within the above concentration ranges is within the scope of the present invention, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9 and 5.0 w / w%.

[0155] In some embodiments, the colorant comprises less than 5% pigment.

[0156] In some embodiments according to the present invention, the colorant comprises at least one white pigment.

[0157] In some embodiments according to the present invention, the colorant comprises at least one black pigment.

[0158] In some embodiments, the at least one colorant is dispersed or at least partially dissolved in water and, optionally, at least one co-solvent.

[0159] In some embodiments, ink formulations according to the present invention may further comprise at least one plasticizer.

[0160] Non-limiting examples of plasticizers include Pluronic 10R5 (BASF), Pluronic 10RP (BASF), GRB-3 (Lubrizol), Byketol PC (BYK), Carbowax 1450 (DOW), Carbowax 3250 (Dow), Tergiltol 15-S-9 (Sigma-Aldrich), Tween 20, Tween 80, Ecosurf SA-9 (DOW), Ecosurf EH-9 (DOW), Synative RPE1050 (BASF), or combinations thereof. Any other plasticizers known in the art are within the scope of the present invention.

[0161] In some embodiments, the ink formulations of the present invention include at least one plasticizer that is poly(ethylene glycol) based, such as Carbowax 1450 (DOW) and Carbowax 3250 (Dow).

[0162] In some embodiments, the ink formulations of the present invention include at least one pluronic® plasticizer that is a poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol) copolymer (i.e., PPG-PEG-PPG copolymer).

[0163] In some embodiments, the ink formulations of the present invention include at least one pluronic plasticizer with a Mw (molecular weight) of about 1,000 g / mol to about 5,000 g / mol inclusive, with any value within the above range being within the scope of the present invention, such as a Mw of about 1,000 g / mol, about 2,000 g / mol, about 3,000 g / mol, about 4,000 g / mol, about 5,000 g / mol, etc.

[0164] In some embodiments, the ink formulations of the present invention include a Pluronic plasticizer, such as Pluronic 10R5 (BASF), Pluronic 10RP (BASF).

[0165] In some embodiments, the ink formulations of the present invention include a plasticizer that is a secondary alcohol ethoxylate, such as Tergiltol 15-S-9 (Sigma-Aldrich) plasticizer.

[0166] In some embodiments, the ink formulations of the present invention include a plasticizer that is an ethoxylated (20) sorbitan ester, such as Tween 20 and Tween 80.

[0167] In some embodiments, the ink formulations of the present invention include a plasticizer that is a modified urea surfactant plasticizer, such as Byketol PC (BYK).

[0168] In some embodiments, the ink formulations of the present invention include a plasticizer that is an alcohol ethoxylate, such as Ecosurf EH-9 (DOW).

[0169] In some embodiments, the ink formulations of the present invention include a plasticizer that is a seed oil surfactant, such as Ecosurf SA-9 (DOW).

[0170] In some embodiments, the ink formulations of the present invention include a plasticizer comprised of a block copolymer of polyethylene oxide and polypropylene oxide, such as Synative RPE1050 (BASF) plasticizer.

[0171] In some embodiments, the ink formulations of the present invention include a polyol plasticizer, such as GRB-3 (Lubrizol).

[0172] In some embodiments, the ink formulations of the present invention include a combination of the plasticizers GRB-3 and Byketol PC.

[0173] In some embodiments according to the present invention, at least one plasticizer is present in the aqueous inkjet ink formulation according to the present invention in a concentration of from about 2.0 w / w% to about 6.0 w / w%, from 2.0 w / w% to 6.0 w / w% inclusive. Any value within the above concentration range is within the scope of the present invention, such as 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9 and 6.0 w / w%.

[0174] In some embodiments according to the present invention, the total content of plasticizer(s) present in the aqueous inkjet ink formulation according to the present invention is from about 2.0 w / w% to about 6.0 w / w%, from 2.0 w / w% to 6.0 w / w% inclusive. Any value within the above concentration range is within the scope of the present invention, such as 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9 and 6.0 w / w%.

[0175] In some embodiments, ink formulations according to the present invention may further comprise at least one dispersant.

[0176] Non-limiting examples of applicable dispersants are polyanionic dispersants and polymeric dispersants.

[0177] In some embodiments, the dispersant is Efka4585 (Evonik).

[0178] In some embodiments according to the present invention, at least one dispersant is present in the aqueous inkjet ink formulation according to the present invention in a concentration of from about 1.0 w / w% to about 4.0 w / w%, from 1.0 w / w% to 4.0 w / w% inclusive. Any value within the above concentration range is within the scope of the present invention, such as 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9 and 4.0 w / w%.

[0179] In some embodiments, the aqueous inkjet ink formulation of the present invention may further comprise at least one rust inhibitor.

[0180] In some embodiments, the rust inhibitor is L-51-Levasil CC151HS.

[0181] In some embodiments, the rust inhibitor is an alkali-metal organosiliconate. Such rust inhibitors have been previously disclosed in commonly owned patent publication

[11] , the contents of which are incorporated herein by reference.

[0182] In some embodiments according to the present invention, the at least one alkali metal organosiliconate is sodium methylsiliconate, which may sometimes be referred to as methyl-silanetriosodium salt or sodium methylsilanetriolate.

[0183] In some embodiments according to the present invention, the at least one alkali metal organosiliconate is sodium methyl siliconate, CAS number 16589-43-8.

[0184] In some embodiments according to the present invention, the at least one alkali metal organosiliconate is potassium methylsiliconate, sometimes referred to as methylsilanetriol potassium salt or potassium methylsilanetriolate.

[0185] In some embodiments according to the present invention, the at least one alkali metal organosiliconate is potassium methylsiliconate having CAS number 31795-24-1.

[0186] In some embodiments, at least one alkali metal organosiliconate is present in the aqueous inkjet ink formulation according to the present invention at a concentration of at least about 0.01 w / w%, sometimes at least about 0.05 w / w%, and even sometimes at least about 0.1 w / w%.

[0187] In some embodiments, the at least one alkali metal organosiliconate is present in the aqueous inkjet ink formulation according to the present invention at a concentration of from about 0.01% w / w to about 4.00% w / w, such as from 0.01% w / w to 4.00% w / w, inclusive. Any value within the above concentration range is within the scope of the present invention, such as 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 192, 194, 195, 196, 197, 198, 199, 200, 201, 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218, 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 9, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.40, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48, 0.49, 0.50, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.60, 0.61, 0.62, 0.63, 0.64, 0.65, 0.66, 0.67, 0.68, 0.69, 0.70, 0.71, 0.72, 0.73, 0.74, 0.75, 0.76, 0.77, 0.78, 0.79, 0.80, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.90, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0 0.98, 0.99, 1.00, 1.10, 1.20, 1.30, 1.40, 1.50, 1.60, 1.70, 1.80, 1.90, 2.00, 2.10, 2.20, 2.30, 2.40, 2.50, 2.60, 2.70, 2.80, 2.90, 3.00, 3.10, 3.20, 3.30, 3.40, 3.50, 3.60, 3.70, 3.80, 3.90 and 4.00 w / w%.

[0188] In some embodiments, the aqueous inkjet ink formulation of the present invention may further comprise at least one antimicrobial agent (biocide) (e.g., Merga K12N or any other antimicrobial agent known in the art), where the antimicrobial agent comprises at most about 1% by weight of the inkjet ink formulation, any value between 0 and 1% is within the scope of the present invention.

[0189] In some embodiments of the present invention, the antimicrobial agent comprises about 0.03% by weight of the ink-jet ink formulation.

[0190] In some embodiments, the aqueous inkjet ink formulation of the present invention may further comprise at least one wax material. Non-limiting examples of wax materials include Deurex 4501, Deurex 4601, Novasperse HD80 (Allinova), Joncryl wax 35 (BASF), Cohesa 1020 (Honeywell), Aquaver 513 (BYK), or combinations thereof. Any other wax materials known in the art are within the scope of the present invention.

[0191] In some embodiments, the at least one wax material is an oxidized polyethylene wax, such as Deurex 4501 and Deurex 4601.

[0192] In some embodiments, the at least one wax material is a High Density Polyethylene (HDPE) wax, such as Novasperse HD80 (Allinova) and Aquaver 513 (BYK).

[0193] In some embodiments, the at least one wax material is a polyethylene wax, such as Joncryl wax 35 (BASF).

[0194] In some embodiments, the at least one wax material comprises an ethylene-acrylic acid copolymer, such as Cohesa 1020 (Honeywell).

[0195] In some embodiments, the wax material is provided in the form of an emulsion, such as, for example, a wax-in-water emulsion.

[0196] In some embodiments, the wax material comprises at most about 3.0% by weight of the ink-jet ink formulation, and sometimes comprises at most about 5.0% by weight of the ink-jet ink formulation. Any value between 0 and 5.0% is within the scope of the present invention, for example, 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9 and 5.0 w / w%.

[0197] In some embodiments, the ink formulation according to the present invention may further comprise at least one additional additive applicable to the inkjet ink of the application. Non-limiting examples of applicable additives include at least one anti-gelling agent (e.g., an acid); at least one pH adjusting agent (e.g., a base); and at least one defoaming agent.

[0198] In some embodiments, the one or more further additives comprise at most about 3.0% by weight of the inkjet ink formulation. Any value between 0 and 3.0% is within the scope of the present invention, such as 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, and 3.0 w / w%.

[0199] In some embodiments, the ink formulations of the present invention may include one or more non-volatile solids.

[0200] In some embodiments, the non-volatile solids comprise at most about 30% by weight of the ink-jet ink formulation, sometimes at most about 25.0% by weight, and still more sometimes at most about 20.0% by weight.

[0201] In some embodiments, the non-volatile solids comprise from about 10 w / w% to about 30 w / w% of the inkjet ink formulation, sometimes from about 10 w / w% to about 20.0 w / w% of the inkjet ink formulation, and still more sometimes from about 15 w / w% to about 22 w / w% of the inkjet ink formulation.

[0202] In some embodiments of the present invention, at least one surfactant of the present invention and one or more additional components (e.g., at least one alkali metal organosiliconate) in the ink formulation can provide additive, and sometimes synergistic, beneficial effects in the printing process of the present invention. Non-limiting beneficial effects are as disclosed herein.

[0203] In some embodiments, for example when the aqueous inkjet ink formulation is used in an indirect printing process or system, the aqueous inkjet ink formulation may further comprise at least one binder (eg, an organic polymeric resin).

[0204] In some embodiments, at least one binder may be dispersible or at least partially soluble in water and any co-solvents.

[0205] In some embodiments, at least one binder is dispersible or at least partially soluble in water and any co-solvents.

[0206] In some embodiments, at least one binder is an organic polymeric resin binder.

[0207] In some embodiments, the at least one binder is an organic polymeric resin binder, which is dispersible or at least partially soluble in water and any co-solvents.

[0208] In some embodiments according to the present invention, at least one binder in the ink formulation is an anionic binder, such as an acrylic binder and / or a sulfone binder. Similar anionic binders are also within the scope of the present invention.

[0209] In some embodiments according to the present invention, at least one binder in the ink formulation is a negatively charged organic polymer resin.

[0210] In some embodiments according to the present invention, the negatively charged organic polymer resin has an average molecular weight of at least 8,000.

[0211] In some embodiments according to the present invention, at least one binder in the ink formulation is an acrylic polymer and / or an acrylic-styrene copolymer (eg, average molecular weight of about 60,000 g / mol).

[0212] In some embodiments according to the present invention, the at least one binder is present in the aqueous inkjet ink formulation according to the present invention in a concentration of from about 5.0 w / w% to about 20.0 w / w%, from 5.0 w / w% to 20.0 w / w% inclusive. Any value within the above concentration range is within the scope of the present invention, for example, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, 14.0, 14.5, 15.0, 16.0, 17.0, 18.0, 19.0 and 20.0 w / w%.

[0213] Non-limiting examples of binders include polystyrene-acrylate copolymers, polyacrylate polymers, polyurethanes (eg, aliphatic polyurethanes such as anionic aliphatic polyurethanes), urethane-acrylate copolymers, and polyesters (eg, polyethylene terephthalate).

[0214] Exemplary styrene-acrylic (or polystyrene-acrylate) copolymers include Joncryl® 77E, Joncryl® 586, Joncryl® 90, Joncryl® 8085, Joncryl® ECO2177.

[0215] Exemplary polyurethanes include NeoRez® R-563, an anionic aliphatic polyurethane from DSM-PUD.

[0216] An exemplary acrylic or polyacrylic binder includes Joncryl® 538 (BASF), an acrylic polymer emulsion.

[0217] Exemplary polyesters include Plascoat Z-105, Plascoat Z-730, and Plascoat Z-750 (all from GOO Chemicals).

[0218] The binder can be provided in a variety of forms, such as a dispersion or emulsion, with water typically being the primary carrier liquid.

[0219] In some embodiments, the binder is a styrene-acrylic emulsion.

[0220] In some embodiments, the ink formulations of the present invention may include one or more of: at least one co-solvent, at least one plasticizer, at least one dispersant, at least one rust inhibitor, at least one antimicrobial agent, at least one wax material, at least one anti-gelling agent, at least one pH control agent, at least one defoamer, and at least one binder.

[0221] The various embodiments detailed herein in relation to the inkjet ink formulation of the present invention are applicable mutatis mutandis to the uses, methods and systems of the present invention.

[0222] In another of its aspects, the present invention provides an aqueous inkjet ink formulation as disclosed herein for use in preventing and / or minimizing and / or reducing sweating (wetting, wetting) of inkjet ink on a print head of a printing system. The print head(s) are used in a printing process that may be direct or indirect. Similarly, the printing system employed may be either a direct system or an indirect system.

[0223] In some embodiments, the aqueous inkjet ink formulations as disclosed herein are also used to improve the printing process and / or to improve the quality of the resulting printed image. The printing process can be direct or indirect.

[0224] In some embodiments, the ink formulations of the present invention are applicable not only to the jetting temperature of the printing process according to the present invention (e.g., about 30° C.), but also to other temperatures operated in the process (e.g., ITM temperatures of about 80° C.).

[0225] In a further aspect thereof, the present invention provides a method for preventing and / or minimizing and / or reducing sweating of inkjet ink on a print head of a printing system (e.g. a print head used in an inkjet printing process and forming part of a printing system), said method comprising utilising (e.g. in a printing process) an aqueous inkjet ink formulation comprising: (a) a solvent containing water; (b) at least one colorant; and (c) at least one surfactant; wherein the ink formulation has a dynamic surface tension of about 37 to about 50 mN / m (measured with a bubble life of about 0.015 seconds) and a static surface tension of about 23.0 to about 25.5 mN / m (measured with a bubble life of about 10 seconds), both of which are measured at room temperature (e.g., about 22° C.) using the bubble pressure method utilizing a Sita bubble pressure tensiometer: Model Sita online (Pro-line T15); and The at least one surfactant is selected to obtain the dynamic surface tension and the static surface tension, thereby preventing and / or minimizing and / or reducing sweating of the inkjet ink on a print head of a printing system.

[0226] In another of its aspects, the present invention provides a method for preventing and / or minimizing and / or reducing sweating of inkjet ink on a print head of a printing system (e.g. a print head used in an inkjet printing process and forming part of a printing system), said method comprising utilising an aqueous inkjet ink formulation of the present invention as disclosed herein.

[0227] In a further aspect thereof, the present invention provides an aqueous inkjet ink formulation as disclosed herein for use in a method for preventing and / or minimizing and / or reducing sweating of inkjet ink on a printhead of a printing system.

[0228] Furthermore, the present invention provides in a further aspect thereof an aqueous inkjet ink formulation as disclosed herein for use in preventing and / or minimizing and / or reducing sweating of the inkjet ink on a print head of a printing system.

[0229] In a further aspect thereof, the present invention provides a method for one or more of improving a printing process and improving the quality of the resulting printed image, said method comprising utilizing (e.g. in the printing process) an aqueous inkjet ink formulation comprising: (a) a solvent containing water; (b) at least one colorant; and (c) at least one surfactant; wherein the ink formulation has a dynamic surface tension of about 37 to about 50 mN / m (measured with a bubble life of about 0.015 seconds) and a static surface tension of about 23.0 to about 25.5 mN / m (measured with a bubble life of about 10 seconds), both of which are measured at room temperature (e.g., about 22° C.) using the bubble pressure method utilizing a Sita bubble pressure tensiometer: Model Sita online (Pro-line T15); and The at least one surfactant is selected to obtain the dynamic surface tension and the static surface tension, thereby improving one or more of the quality of the printing process and the resulting printed image.

[0230] In another of its aspects, the present invention provides a method for one or more of improving a printing process and improving the quality of the resulting printed image, the method comprising utilizing in the printing process an aqueous inkjet ink formulation as disclosed herein.

[0231] In a further aspect thereof, the present invention provides an aqueous inkjet ink formulation as disclosed herein for use in a method for one or more of improving the printing process and improving the quality of the resulting printed image.

[0232] Furthermore, in a further aspect thereof, the present invention provides an aqueous inkjet ink formulation as disclosed herein for use in one or more of improving the printing process and improving the quality of the resulting printed image.

[0233] Non-limiting examples of improvements achieved by the ink formulations of the present invention include one or more of the following: improved jetting stability over time, more available print cycles / run (especially due to reduced ink build-up in the ink nozzles); improved print head life; ease of maintenance; improved process stability; and print uniformity, ink wetting on the ITM, dot size, ink spreading characteristics, missing nozzle compensation, and print head compatibility.

[0234] In some embodiments, an improvement in the printing process and / or the quality of the resulting printed images is reflected in the non-sweating behavior of the ink formulations of the present invention.

[0235] In another of its aspects, the present invention provides an aqueous inkjet ink formulation as disclosed herein, for use in a printing process, such as described herein.

[0236] In a further aspect thereof, the present invention provides an aqueous inkjet ink formulation as disclosed herein, said formulation forming part of a printing system, for example as described herein.

[0237] In a further aspect thereof, the present invention provides a method of printing utilizing the aqueous inkjet ink formulation as disclosed herein.

[0238]

[0033] Moreover, in a further aspect, the present invention provides a method of printing on a substrate, said method comprising ink-jetting an ink formulation onto a print substrate by utilizing one or more print bars each comprising one or more printheads, thereby forming an ink image on said substrate, wherein the ink formulation is an aqueous ink-jet ink formulation according to the present invention.

[0239] In some embodiments, the printing method of the present invention is a method for one or more of improving the printing process and improving the quality of the resulting printed image.

[0240] In another aspect thereof, the present invention provides a method of printing comprising: providing an intermediate transfer member having a release layer surface; ink-jetting an ink formulation onto the release layer surface by utilizing one or more print bars, each print bar comprising one or more print heads, thereby forming an ink image on the release layer surface; and transferring said ink image from the intermediate transfer member to a print substrate; wherein said ink formulation is an aqueous inkjet ink formulation according to the present invention.

[0241] In some embodiments, the method can further include substantially drying the ink image formed on the intermediate transfer member, and transferring the substantially dried ink image from the intermediate transfer member to a print substrate.

[0242] The present invention provides in a further aspect a method of printing, the method being selected from: (i) a direct method of printing on a substrate, the method comprising ink-jetting an ink formulation onto a print substrate by utilizing one or more print bars, each print bar comprising one or more printheads, thereby forming an ink image on the substrate, wherein the ink formulation is an aqueous ink-jet ink formulation according to the present invention; or (ii) A method of indirect printing, said method comprising: providing an intermediate transfer member having a release layer surface; ink-jetting an ink formulation onto the release layer surface by utilizing one or more print bars, each print bar comprising one or more print heads, thereby forming an ink image on the release layer surface; and transferring said ink image from the intermediate transfer member to a print substrate; Including, wherein the ink formulation is an aqueous inkjet ink formulation according to the present invention, and the method may further comprise substantially drying the ink image formed on the intermediate transfer member, and transferring the substantially dried ink image from the intermediate transfer member to a printing substrate.

[0243] Additionally, in a further aspect thereof, the present invention provides a printing system comprising an aqueous inkjet ink formulation as disclosed herein.

[0244] In another aspect thereof, the present invention provides a printing system comprising an image-forming station comprising one or more print bars, each print bar configured to hold an ink formulation and comprising one or more print heads, each of said one or more print heads configured to jet said ink formulation onto a print substrate to form an ink image on said substrate, wherein at least one of said one or more print bars is configured to hold an aqueous inkjet ink formulation according to the present invention.

[0245] In a further aspect thereof, the present invention provides a printing system comprising: an intermediate transfer member having a release layer surface; an imaging station comprising one or more print bars, each print bar configured to hold an ink formulation, and comprising one or more print heads, each of the one or more print heads configured to jet the ink formulation onto the release layer surface to form an ink image thereon, wherein at least one of the one or more print bars is configured to hold an aqueous ink-jet ink formulation according to the present invention; and A transfer station for transferring the ink image from the intermediate transfer member to a print substrate.

[0246] The present invention in a still further aspect provides a printing system and process substantially as described herein.

[0247] Additionally, the present invention in a further aspect provides an aqueous inkjet ink formulation substantially as described herein.

[0248] In another of its aspects, the present invention provides an aqueous inkjet ink formulation having dynamic and static surface tensions as illustrated and described herein.

[0249] As discussed above, the inkjet ink formulations of the present invention can be used in direct or indirect printing processes utilizing direct and indirect printing systems, respectively.

[0250] In some embodiments, the printing process is a direct printing process, i.e., the ink formulation is jetted directly onto the final print substrate.

[0251] In some embodiments, the printing process is an indirect printing process in which the release surface of an intermediate transfer member (ITM) is pretreated (e.g., coated) with a treatment formulation (e.g., an aqueous treatment formulation) prior to depositing an ink image. The treatment formulation is applied to the surface of the ITM, where it forms a thin wet treatment layer, which is subjected to a drying process on the ITM release surface, leaving a thin substantially dry treatment layer (which may be in the form of a film or in the form of a non-film, e.g., a non-cohesive treatment layer) on the ITM release surface. Then, droplets of an aqueous ink formulation are inkjet-deposited on the substantially dry thin treatment layer (e.g., film or non-film), where it forms an ink image. Then, the formed ink image is subjected to a drying process, leaving an ink residue on the substantially dry treatment layer. Then, the substantially dried ink image, together with the thin substantially dry treatment layer, is transferred from the ITM surface to a final printing substrate (e.g., foil-based, paper-based, plastic-based).

[0252] Examples of such printing processes and systems are disclosed in the applicant's patent publications WO2017 / 208152 (PCT / IB2017 / 053177) [3] and WO2013 / 132418 (PCT / IB2013 / 051716) [4], and in the applicant's patent application PCT / IL2023 / 050117

[12] , the contents of each of which are incorporated herein by reference. Furthermore, examples of applicable processing formulations are disclosed in the applicant's patent publications WO2020 / 141465 (PCT / IB2020 / 050001)

[10] and in the applicant's patent application PCT / IL2023 / 050117

[12] , the contents of each of which are incorporated herein by reference.

[0253] Briefly, Figure 1 is an illustration of an exemplary indirect printing system. In particular, Figure 1 is a schematic side view of a digital printing system 10 according to some embodiments of the present invention. In some embodiments, system 10 includes a rolling flexible blanket 12 that circulates through an imaging station 14, a drying station 16, an impression station 18, and a blanket treatment station 20.

[0254] As used herein, the term "blanket" refers to a flexible transfer member that can be mounted in a printing apparatus to form a belt-like structure over two or more rollers, at least one of which can rotate and move the blanket (e.g., by moving the belt) around the rollers.

[0255] As used herein, the terms "blanket" and "intermediate transfer member" (ITM) are used interchangeably and refer to a flexible member including at least a release layer that is used as an intermediate member configured to receive an ink image and transfer the ink image to a target substrate.

[0256] In an operational mode, the imaging station 14 is configured to form a mirror ink image (also referred to herein as an "ink image") (not shown) of a digital image on a surface of an upper run of the blanket 12. The ink image is then transferred to a target substrate (e.g., paper, a folding carton, or any suitable flexible packaging in the form of a sheet or continuous web) located beneath the lower run of the blanket 12.

[0257] As used herein, the terms "ink image" and "image" are interchangeable. The terms sometimes refer to the image formed on blanket 12 and transferred to a target substrate. Sometimes the terms refer to the printed image on the substrate itself (e.g., paper, folding cartons, any suitable flexible packaging in sheets or in a continuous web). Thus, these terms should be interpreted within the context of the text in which they are used.

[0258] As used herein, the term "run" refers to the length or section of blanket 12 between any two given rollers along which blanket 12 is guided.

[0259] In some embodiments, the installation blanket 12 can be bonded (e.g., seamed) end-to-end to form a continuous blanket loop (not shown). Example methods and systems for seam attachment are described in detail in commonly owned patent publication WO2019 / 012456 (PCT / IB2018 / 055126)[5], the disclosure of which is incorporated herein by reference.

[0260] In some embodiments, imaging station 14 typically includes multiple print bars 22 each mounted (e.g., with a slider) on a frame (not shown) positioned at a fixed height above the surface of the top run of blanket 12. In some embodiments, each print bar 22 includes a strip of print heads the same width as the print area on blanket 12, with individually controllable print nozzles.

[0261] In some embodiments, imaging station 14 may include any suitable number of bars 22, and each bar 22 may include a printing fluid, such as a water-based ink formulation, of a different color. The inks typically have visible colors, such as, but not limited to, cyan, magenta, red, green, blue, yellow, black, and white. In the example of FIG. 1, imaging station 14 includes seven print bars 22, but may include four print bars 22 having any selected color, such as, for example, cyan, magenta, yellow, and black.

[0262] In some embodiments, one or more of the print bars can comprise an aqueous inkjet ink formulation of the present invention. Sometimes, all of the print bars utilized in a printing method / system can comprise an aqueous inkjet ink formulation of the present invention.

[0263] In some embodiments, the print heads are configured to eject ink droplets of different colors onto the surface of blanket 12 so as to form ink images (not shown) on the surface of blanket 12 .

[0264] In some embodiments, the different print bars 22 are spaced apart from one another along the axis of motion of the blanket 12, represented by arrow 24. In this configuration, precise spacing between the bars 22 and synchronization between the direction of the ink droplets of each bar 22 and the motion of the blanket 12 is essential to enable correct placement of the image pattern.

[0265] In some embodiments, the system 10 includes a heater, such as a hot gas or air blower 26 disposed between the print bars 22 and configured to partially dry the ink droplets deposited on the surface of the blanket 12 .

[0266] This hot air flow between the print bars can help, for example, to reduce condensation on the surface of the print head, and / or to deal with satellites (e.g., residue or small droplets distributed around the main ink droplets), and / or to prevent blockage of the inkjet nozzles of the print head, and / or to prevent droplets of different colors of ink on the blanket 12 from undesirably merging with one another. In some embodiments, the system 10 includes a drying station 16 configured to blow hot air (or another gas) onto the ink image on the surface of the blanket 12. In some embodiments, the drying station includes a blower or any other suitable drying device, such as an infrared (IR) dryer.

[0267] At drying station 16, the ink image formed on blanket 12 is exposed to radiation and / or hot air to more completely dry the ink, until most or all of the liquid carrier has evaporated, leaving only a layer of resin and colorant that has been heated to a tacky ink film.

[0268] In some embodiments, system 10 includes a blanket transport assembly 26' configured to move a rolling ITM, such as blanket 12. In some embodiments, blanket transport / guide assembly 26' includes one or more rollers 28, at least one of which includes an encoder (not shown) configured to record the position of blanket 12 so as to control the position of segments of blanket 12 relative to the respective print bars 22. In some embodiments, the encoder of roller 28 typically includes a rotary encoder configured to generate a rotation-based position signal indicative of the angular displacement of the respective roller.

[0269] Additionally or alternatively, blanket 12 may include an integrated encoder (not shown) for controlling the operation of various modules of system 10. Integrated encoders are described in detail, for example, in commonly owned patent publication WO2020 / 003088 (PCT / IB2019 / 055288) [6], the disclosure of which is incorporated herein by reference.

[0270] In some embodiments, system 10 includes an impression station 18 where blanket 12 passes between impression cylinder 30 and pressure cylinder 32, which are pressed to transfer the image carried by blanket 12 to substrate 38, as described in more detail below.

[0271] In some embodiments, the system 10 includes a control console (not shown) configured to control multiple modules and assemblies of the system 10 .

[0272] In some embodiments, the blanket treatment station 20, which may also function as a cooling and / or washing station, is configured to treat the blanket, for example, by cooling the blanket and / or applying a treatment fluid to the exterior surface of the blanket 12 and / or washing the exterior surface of the blanket 12. This treatment may be performed by passing the blanket 12 over one or more rollers or blades configured to apply cooling and / or washing and / or treatment fluid to the exterior surface of the blanket.

[0273] In the example of FIG. 1, station 20 is mounted between two particular rollers 28, however, station 20 may be mounted adjacent blanket 12 in any other suitable location between impression station 18 and image forming station 14.

[0274] In some embodiments, the impression cylinder 30 of the impression station 18 is configured to impress an ink image onto a target substrate, such as an individual sheet 34 or a continuous web substrate, which is transported by a substrate transport module 36 (shown diagrammatically) from an input stack 38 through the impression cylinder 30 to an output stack 40. In some embodiments, the target substrate may include any suitable substrate, such as, but not limited to, a flexible substrate, a partially flexible substrate (e.g., having a flexible section and a rigid section), or a rigid substrate.

[0275] In some embodiments, system 10 includes an additional impression station (not shown) to allow for double-sided printing (ie, printing on both sides of sheet 34).

[0276] In alternative embodiments, different configurations of substrate conveyor 36 can be used for printing on continuous web substrates, as disclosed, for example, in PCT International Publication No. WO2020 / 136517 (PCT / IB2019 / 061081) [9]. Detailed descriptions and various configurations of sheet-fed single and double-sided printing systems and systems for printing on continuous web substrates are provided, for example, in PCT International Publication No. WO2013 / 132420 (PCT / IB2013 / 051718) [7] and PCT International Publication No. WO2015 / 036906 (PCT / IB2014 / 064277) [8], the disclosures of each of which are incorporated herein by reference.

[0277] The particular configuration of system 10 is provided by way of example, however, embodiments of the invention are in no way limited to this particular type of exemplary system, and the principles described herein may be applied to any other type of printing system as well.

[0278]

[0023] Thus, in another aspect thereof, the present invention provides an indirect printing system and an indirect printing process, e.g. as described in one or more of [3], [4] and

[12] , utilising the inkjet ink formulation of the present invention.

[0279] In another aspect thereof, the present invention provides a printing system comprising an image-forming station comprising one or more print bars, each print bar configured to hold an ink formulation and comprising one or more print heads, each of said one or more print heads configured to jet said ink formulation onto a print substrate to form an ink image on said substrate, wherein at least one of said one or more print bars is configured to hold an aqueous inkjet ink formulation according to the present invention.

[0280] In some embodiments, the printed substrate is substantially as disclosed herein.

[0281] In some embodiments, the print head or print heads are substantially as disclosed herein.

[0282] In yet a further aspect thereof, the present invention provides a printing system comprising: an intermediate transfer member having a release layer surface; an imaging station comprising one or more print bars, each print bar configured to hold an ink formulation, and comprising one or more print heads, each of the one or more print heads configured to jet the ink formulation onto the release layer surface to form an ink image thereon, wherein at least one of the one or more print bars is configured to hold an aqueous ink-jet ink formulation according to the present invention; and A transfer station for transferring the ink image from the intermediate transfer member to a print substrate.

[0283] In some embodiments, the systems of the present invention can further include a drying station configured to substantially dry (or sometimes partially dry) the ink image formed on the intermediate transfer member, and a transfer station configured to transfer the substantially dried (or sometimes partially dried) ink image from the intermediate transfer member to a printing substrate.

[0284] As used herein above and below, the term "substantially dry" or any linguistic variation thereof may be envisaged as being partially dry, sometimes as being dry to the extent that the solvent(s) and / or co-solvent(s) and / or water and / or any volatile component(s) are present in trace amounts (e.g., amounts that do not interfere with the performance of one or more of the system, the printing process and the print quality), or even sometimes as being completely dry.

[0285] In some embodiments, the intermediate transfer member is substantially as disclosed herein.

[0286] In some embodiments, the print head or print heads are substantially as disclosed herein.

[0287] In some embodiments, the transfer station is substantially as disclosed herein.

[0288] In some embodiments, the drying station is substantially as disclosed herein.

[0289] In some embodiments, the printed substrate is substantially as disclosed herein.

[0290] In some embodiments, the printhead of the present invention forms part of a direct printing system.

[0291] In some embodiments, the printhead of the present invention is an inkjet printhead.

[0292] In some embodiments, the printhead of the present invention forms part of an indirect printing system.

[0293] In some embodiments, a printhead of the present invention comprises a printhead nozzle plate.

[0294] Printheads of the present invention, such as printheads, are available, for example, from FUJIFILM Dematix Co., Ltd. (Tokyo, Japan).

[0295] In a further aspect thereof, the present invention provides a printing system selected from: (i) a direct printing system comprising an imaging station comprising one or more print bars, each print bar configured to hold an ink formulation and comprising one or more print heads, each of said one or more print heads configured to jet said ink formulation onto a print substrate to form an ink image on said substrate, wherein at least one of said one or more print bars is configured to hold an aqueous inkjet ink formulation according to the present invention; or (ii) An indirect printing system comprising: an intermediate transfer member having a release layer surface; an imaging station comprising one or more print bars, each print bar configured to hold an ink formulation, and comprising one or more print heads, each of the one or more print heads configured to jet the ink formulation onto the release layer surface to form an ink image thereon, wherein at least one of the one or more print bars is configured to hold an aqueous ink-jet ink formulation according to the present invention; and a transfer station for transferring the ink image from the intermediate transfer member to the printing substrate, the system may further include a drying station configured to substantially dry (and sometimes partially dry) the ink image formed on the intermediate transfer member, and the transfer station configured to transfer the substantially dried (and sometimes partially dried) ink image from the intermediate transfer member to the printing substrate; The indirect printing system.

[0296] Unless otherwise specified, "concentration" refers to w / w (weight percent concentration), i.e., the weight of a component of an aqueous inkjet ink formulation per total weight of the formulation.

[0297] As used herein above and below, the term "about" refers to ±10% of the indicated value.

[0298] In some embodiments, the aqueous inkjet ink formulations of the present invention have contact angles (CA) as exemplified herein and as shown, for example, in the figures.

[0299] In some embodiments, the aqueous inkjet ink formulations of the present invention have a DST (static surface tension) and SST (dynamic surface tension) as exemplified herein and as shown, for example, in the Figures.

[0300] In some embodiments, the aqueous inkjet ink formulations of the present invention have a viscosity as exemplified herein.

[0301] In some embodiments, the viscosity of the aqueous inkjet ink formulations of the present invention is from about 7.2 cP to about 8.5 cP, and sometimes from about 7.5 cP to about 8.5 cP. Any value within the above range is within the scope of the present invention, such as 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, 8.4, and 8.5.

[0302] In some embodiments, the aqueous inkjet ink formulation is as exemplified herein.

[0303] In some embodiments, the inkjet ink formulation of the present invention comprises the following components and has the viscosity and static surface tension (SST) detailed in Table 1 below: [Table 1]

[0304] In some embodiments, the inkjet ink formulation of the present invention has a DST and SST as detailed in Table 2 below: [Table 2] EXAMPLES

[0305] Detailed Description of the Embodiments The following examples illustrate inkjet ink formulations in accordance with the teachings of the present disclosure and are not intended to limit the scope of the invention as recited in the claims.

[0306] Example 1: Ink formulations and their properties The following formulations were prepared using materials supplied under the indicated trademarks, however, such materials may be substituted with other commercially available materials, e.g., compounds having similar formula content and other characteristics.

[0307] The following ink formulation is a black (K) color ink composed of the following pigments: Heliogen Blue D7079, Black Pearls 4350, Hostaperm Violet P-RL. Alternative colorants (whether pigments or dyes) that may be suitable for such formulations are readily known to those skilled in the art of formulating printing inks.

[0308] Ink formulations were prepared according to general procedures known in the art, see for example [2], the contents of which are incorporated herein by reference.

[0309] The viscosity of the ink formulations was measured at room temperature (RT) using a viscometer (Brookfield DV II+Pro).

[0310] Dynamic surface tension (DST) was measured at room temperature (RT) (as specified, e.g., 21.0°C, 21.5°C, 22.0°C and 22.5°C) using a Sita bubble pressure tensiometer: Model Sita online (Pro-line T15) (bubble lifetime, control range 15ms-20,000ms, resolution 1ms).

[0311] Static surface tension (SST) (10 second bubble life) was also measured at RT (as specified, e.g. 21.0°C, 21.5°C, 22.0°C and 22.5°C) using a Sita bubble pressure tensiometer: Model Sita online (Pro-line T15).

[0312] Static surface tension was also measured using a standard liquid tensiometer, a Kruss force tensiometer (model K20), at a frequency of 5 Hz and at RT (as specified, e.g., 21.0°C, 23.6°C, 23.8°C, 23.9°C and 24.0°C).

[0313] The contact angle (CA) of the ink on a blanket coated with the treatment formulation (see

[10] ) was measured using CA data physics measurements.

[0314] Ink sweating (wetting) on ​​the PH (print head) was measured by visual inspection of the print head and compared with evaluating the print quality on the final print substrate by counting the number of missing nozzles under given printing conditions. Missing nozzles are those that have not performed well, such as nozzles that have become clogged as a result of ink sweating.

[0315] The ink formulations investigated and some test parameters are listed below in Table 3. The content of the specified components is given as weight percent (w / w%) of the drug substance (whether a liquid or solid chemical containing the substance of interest or a dilute solution, dispersion or emulsion), where the weight percent is based on the total weight of the final formulation. It should be noted that these formulations contain further additive(s) known in the art of inkjet inks.

[0316] Table 3 details four ink formulations (1-4) that are not in accordance with the present invention, i.e., they do not meet the DST profile according to the present invention.

[0317] Table 3 provides further details of five ink formulations (A-E) according to the present invention, i.e., these ink formulations meet the DST profile according to the present invention.

[0318] [Table 3]

[0319] Table 4 below details the DST and SST of five ink formulations (A-E) according to the present invention.

[0320] [Table 4]

[0321] Various properties / parameters of ink formulations according to the invention were tested and compared with ink formulations not according to the invention.

[0322] Figures 2A-2B show the dynamic surface tension profile (time scale) of ink formulation A according to the present invention compared to ink formulations 1, 2 and 3. Figure 2B is an enlarged view of Figure 2A. Figure 3 shows the log scale of the dynamic surface tension profiles observed in Figures 2A-2B.

[0323] 2A-2B and FIG. 3 show that Ink Formulation A has a higher value of DST in the high frequency region compared to Ink Formulations 1-3.

[0324] It should be noted that both ink formulations 1-3 not according to the present invention and ink formulation A according to the present invention meet the wetting requirements of the indirect printing process in which they are used. These requirements are reflected in the SST of these formulations, the values ​​of which are detailed in Table 3 above. However, when ink formulations 1-3 were used in the indirect printing process of the present invention, extensive ink sweating at the print head nozzles was observed. When ink formulation A according to the present invention was used, the ink sweating was significantly reduced. This is clearly observed in Figures 4A-4D.

[0325] Figures 4A-4D show images of the nozzle plate (top panels) and the resulting print substrate (bottom panels) using ink formulations 1-3 and A, respectively. Figures 4A-4C clearly show the sweating phenomenon observed with the ink formulations not according to the invention, i.e. formulations 1-3. This sweating was significantly reduced by formulation A of the invention (Figure 4D). The print quality was directly affected by the sweating effect of the ink formulations. This is shown in the lower panels of Figures 4A-4D, where the ink formulations not according to the invention showed printed images with many light areas / stripes indicating ink missing, i.e. missing nozzles where the ink was not jetting properly.

[0326] It is noted that the ink formulation A of the present invention contains the silicone surfactant BYK-3456, while ink formulations 1-3 contain the silicone surfactants Tego 240 and Tego 280. Without wishing to be bound by theory, the present inventors believe that BYK-3456 has a DST applicable to the present invention that is "lazier", i.e. the BYK-3456 surfactant comes to the surface of the ink droplets more slowly, compared to the Tego 240 and Tego 280 surfactants, which is advantageous, inter alia, in reducing / preventing ink sweating in the printhead nozzles of the printing system.

[0327] The spreading rate performance of ink formulations according to the invention was also compared to ink formulations not according to the invention. The spreading rate of the ink correlates with the contact angle of the ink.

[0328] Figures 5A-5B show ink contact angle (CA) measurements as a function of run number (i.e. time, measured approximately every 3-7 seconds) on a hydrophobic ITM coated with treatment formulations at 80°C. Figure 5B is a magnified view of Figure 5A. Representations in Figures 5A-5B are for ink formulations 1-3 and ink formulation A. The figures show good performance of all formulations in terms of ink contact angle, with a decrease in CA as a function of print cycles that is expected in the printing process. Thus, ink formulations according to the present invention showed similar scaling properties as ink formulations with low surface tension, but without the drawback of ink sweating at the print head nozzles associated with ink formulations with low surface tension.

[0329] Figures 6A-6B show the dynamic surface tension profiles (time scale) of ink formulations B and C according to the invention compared to ink formulation 4 not according to the invention. Figure 6B is an enlarged view of Figure 6A. Figure 7 shows the logarithmic scale of the dynamic surface tension profiles observed in Figures 6A-6B.

[0330] 6A-6B and FIG. 7 show that Ink Formulations B and C have higher values ​​of DST in the high frequency region compared to Ink Formulation 4.

[0331] Inventive ink formulation B contained a mixture of silicone surfactant BYK-3456 and non-silicone surfactant Surfynol PSA336. Inventive ink formulation C contained silicone surfactant BYK-3456, while non-inventive ink formulation 4 contained silicone surfactants Tego240 and Tego270. Without wishing to be bound by theory, the inventors believe that BYK-3456 and the combination of BYK-3456 and Surfynol PSA336 have a DST applicable to the present invention that is "more retarding" compared to the Tego240 and Tego270 surfactants, i.e. the inventive surfactants come to the surface of the ink drop more slowly.

[0332] Figure 8 shows the dynamic surface tension profiles (time scale) of ink formulations A, D and E (different viscosities but adjusted with co-solvent polyethylene glycol to meet jetting requirements). Figure 9 shows the dynamic surface tension profiles (log scale) of these ink formulations. From Figures 8 and 9, it can be seen that the dynamic surface tension profiles of ink formulations D and E are very similar to that of ink formulation A, which is shown in Figures 2A-2B and 3 as detailed above.

[0333] Exemplary embodiments The following embodiments are illustrative and are not intended to limit the claimed subject matter. Furthermore, any embodiment detailed herein above in relation to other aspects of the invention is deemed to relate mutatis mutandis to any embodiment detailed herein below.

[0334] EMBODIMENT 1 (a) a solvent containing water; (b) at least one colorant; and (c) at least one surfactant; 1. An aqueous inkjet ink formulation comprising: The ink formulation has a dynamic surface tension of about 37 to about 50 mN / m (measured with a bubble life of about 0.015 seconds) and a static surface tension of about 23.0 to about 25.5 mN / m (measured with a bubble life of about 10 seconds), both of which are measured at room temperature (RT) using the bubble pressure method utilizing a Sita bubble pressure tensiometer: Model Sita online (Pro-line T15); and The aqueous inkjet ink formulation, wherein the at least one surfactant is selected to obtain the dynamic surface tension and the static surface tension.

[0335] Embodiment 2. The aqueous inkjet ink formulation according to embodiment 1, wherein the static surface tension of the ink formulation is further measured using a standard liquid tensiometer, a Kruss force tensiometer (K20 model), at a frequency of 5 Hz at RT, and said static surface tension is about 23.8 to about 24.5 mN / m.

[0336]

[0023] Embodiment 3. The aqueous ink-jet ink formulation of embodiment 1 or 2, wherein the at least one surfactant is a first type of surfactant and / or a second type of surfactant.

[0337]

[0023] Embodiment 4. The aqueous ink-jet ink formulation of embodiment 3, wherein the first type of surfactant is a silicone surfactant.

[0338] Embodiment 5. The aqueous ink-jet ink formulation of embodiment 4, wherein the silicone surfactant is selected from the group consisting of polyether modified polydimethylsiloxanes, polyether modified siloxanes, siloxane based gemini surfactants, and any combination thereof.

[0339]

[0023] Embodiment 6. The aqueous ink-jet ink formulation of embodiment 5, wherein the siloxane based gemini surfactant is Tego4100.

[0340]

[0023] Embodiment 7. The aqueous ink-jet ink formulation of embodiment 5, wherein the polyether modified siloxane surfactant is selected from the group consisting of Byk349, BYK348, BYK-3455, and any combination thereof.

[0341]

[0023] Embodiment 8. The aqueous ink-jet ink formulation of embodiment 5, wherein the polyether-modified polydimethylsiloxane surfactant is BYK-3456.

[0342]

[0023] Embodiment 9. The aqueous ink-jet ink formulation of embodiment 5, wherein the silicone surfactant is a polyether-modified polydimethylsiloxane having at least about 4 polyether-modified repeat units.

[0343]

[0023] Embodiment 10. The aqueous ink-jet ink formulation of embodiment 5, wherein the silicone surfactant is a polyether-modified siloxane having at least about 4 polyether-modified repeat units.

[0344]

[0023] Embodiment 11. The aqueous ink-jet ink formulation of embodiment 4, wherein the silicone surfactant is selected from the group consisting of Tego 4100, Byk 349, BYK 348, BYK-3456, BYK-3455, and any combination thereof.

[0345]

[0023] Embodiment 12. The aqueous ink-jet ink formulation of embodiment 3, wherein the second type of surfactant is a non-silicone surfactant.

[0346]

[0023] Embodiment 13. The aqueous ink-jet ink formulation of embodiment 12, wherein the non-silicone surfactant is a mixture of an ethoxylated acetylenic diol and dioctyl sodium sulfosuccinate in a solvent.

[0347]

[0023] Embodiment 14. The aqueous ink-jet ink formulation of embodiment 13, wherein the non-silicone surfactant is Surfynol PSA336.

[0348]

[0031] Embodiment 15. An aqueous inkjet ink formulation according to any one of the preceding embodiments, wherein the at least one surfactant is a first type of surfactant that is a silicone surfactant, and the ink formulation optionally further comprises at least one surfactant of a second type that is a non-silicone surfactant.

[0349]

[0031] Embodiment 16. An aqueous inkjet ink formulation according to any one of the preceding embodiments, wherein the at least one surfactant is a second type of surfactant that is a non-silicone surfactant, and the ink formulation optionally further comprises at least one surfactant of a first type that is a silicone surfactant.

[0350]

[0031] Embodiment 17. An aqueous ink-jet ink formulation according to any one of the preceding embodiments, wherein the at least one surfactant is a first type of surfactant that is a silicone surfactant selected from the group consisting of polyether modified polydimethylsiloxanes, polyether modified siloxanes, siloxane based gemini surfactants, and any combination thereof, and the ink formulation optionally further comprises at least one surfactant of a second type that is a mixture of an ethoxylated acetylenic diol and dioctyl sodium sulfosuccinate in a solvent.

[0351]

[0041] Embodiment 18. An aqueous inkjet ink formulation according to any one of the preceding embodiments, wherein the at least one surfactant is a first type of surfactant that is a silicone surfactant selected from the group consisting of Tego 4100, Byk 349, BYK 348, BYK-3456, BYK-3455, and any combination thereof, and the ink formulation optionally further comprises at least one surfactant of a second type that is Surfynol PSA.

[0352]

[0041] Embodiment 19. An aqueous inkjet ink formulation according to any one of the preceding embodiments, wherein the at least one surfactant is a first type of surfactant that is BYK-3456, and the ink formulation optionally further comprises at least one surfactant of a second type that is Surfynol PSA.

[0353]

[0041] Embodiment 20. An aqueous ink-jet ink formulation according to any one of embodiments 1 to 19, wherein the at least one surfactant is present in the aqueous ink-jet ink formulation at a concentration of from about 0.1% w / w to about 3.0% w / w.

[0354]

[0041] Embodiment 21. An aqueous inkjet ink formulation according to any one of embodiments 1 to 20, wherein the at least one surfactant is a first type of surfactant present in the aqueous inkjet ink formulation at a concentration of from about 0.1 w / w% to about 3.0 w / w%.

[0355]

[0041] Embodiment 22. An aqueous inkjet ink formulation according to any one of embodiments 1 to 21, wherein the at least one surfactant is a second type of surfactant present in the aqueous inkjet ink formulation at a concentration of from about 0.1 w / w% to about 0.5 w / w%.

[0356] Embodiment 23. An aqueous ink-jet ink formulation according to any one of embodiments 1 to 22, wherein the at least one surfactant is a first type of surfactant and a second type of surfactant, the first type of surfactant being present in the aqueous ink-jet ink formulation at a concentration of from about 0.1 w / w % to about 3.0 w / w %, and the second type of surfactant being optionally present in the aqueous ink-jet ink formulation at a concentration of from about 0.0 w / w % to about 0.5 w / w %.

[0357]

[0046] Embodiment 24. An aqueous ink-jet ink formulation according to any one of the preceding embodiments, wherein water constitutes at least about 30% w / w of the formulation, sometimes at least about 40% w / w, and sometimes at least about 50% w / w or more.

[0358]

[0041] Embodiment 25. An aqueous ink-jet ink formulation according to any one of embodiments 1 to 24, wherein the formulation further comprises at least one co-solvent, such as a humectant.

[0359]

[0041] Embodiment 26. The aqueous inkjet ink formulation of any one of embodiments 1 to 25, wherein the formulation further comprises at least one plasticizer.

[0360]

[0041] Embodiment 27. The aqueous inkjet ink formulation of any one of embodiments 1 to 26, wherein the formulation further comprises at least one dispersant.

[0361]

[0041] Embodiment 28. The aqueous ink-jet ink formulation of any one of embodiments 1 to 27, wherein the formulation further comprises at least one rust inhibitor.

[0362]

[0041] Embodiment 29. The aqueous ink-jet ink formulation of any one of embodiments 1 to 28, wherein the formulation further comprises at least one antimicrobial agent.

[0363]

[0041] Embodiment 30. The aqueous ink-jet ink formulation of any one of embodiments 1 to 29, wherein the formulation further comprises at least one wax material.

[0364]

[0041] Embodiment 31. An aqueous ink-jet ink formulation according to any one of the preceding embodiments, wherein the formulation further comprises one or more of at least one anti-gelling agent, at least one pH control agent, and at least one defoaming agent.

[0365]

[0041] Embodiment 32. The aqueous inkjet ink formulation of any one of embodiments 1 to 31, wherein the formulation further comprises at least one binder (e.g., an organic polymer resin).

[0366]

[0036] Embodiment 33. A method for one or more of improving a printing process and improving the quality of a resulting printed image, the method comprising: (a) a solvent containing water; (b) at least one colorant; and (c) at least one surfactant; and utilizing (e.g., in a printing process) an aqueous ink-jet ink formulation comprising The ink formulation has a dynamic surface tension of about 37 to about 50 mN / m (measured with a bubble life of about 0.015 seconds) and a static surface tension of about 23.0 to about 25.5 mN / m (measured with a bubble life of about 10 seconds), both of which are measured at room temperature (e.g., about 22° C.) using the bubble pressure method utilizing a Sita bubble pressure tensiometer: Model Sita online (Pro-line T15); and The method, wherein the at least one surfactant is selected to obtain the dynamic surface tension and the static surface tension, thereby improving one or more of the quality of the printing process and the resulting printed image.

[0367]

[0081] Embodiment 34. The method of embodiment 33, wherein the aqueous inkjet ink formulation is the formulation described in any one of embodiments 1 to 32.

[0368]

[0081] Embodiment 35. The aqueous inkjet ink formulation of any one of embodiments 1 to 32 for use in a printing process, wherein the printing process is a direct process or an indirect process.

[0369]

[0081] Embodiment 36. A method of printing utilizing an aqueous inkjet ink formulation according to any one of embodiments 1 to 32.

[0370] Embodiment 37. A printing system comprising the aqueous inkjet ink formulation of any one of embodiments 1 to 32.

[0371] Embodiment 38. A printing system comprising an image-forming station comprising one or more print bars, each print bar configured to hold an ink formulation, and comprising one or more print heads, each of the one or more print heads configured to jet the ink formulation onto a print substrate to form an ink image on the substrate, wherein at least one of the one or more print bars is configured to hold the aqueous ink-jet ink formulation of any one of embodiments 1 to 32.

[0372]

[0039] Embodiment 39 is a printing system comprising: an intermediate transfer member having a release layer surface; an imaging station comprising one or more print bars, each print bar configured to hold an ink formulation, and comprising one or more print heads, each of the one or more print heads configured to jet the ink formulation onto the release layer surface to form an ink image thereon, wherein at least one of the one or more print bars is configured to hold the aqueous ink-jet ink formulation of any one of embodiments 1-32; and a transfer station for transferring the ink image from the intermediate transfer member to a print substrate; The printing system.

[0373]

[0040] Embodiment 40: The system of embodiment 39, further comprising a drying station configured to substantially dry the ink image formed on the intermediate transfer member, the transfer station configured to transfer the substantially dried ink image from the intermediate transfer member to a printing substrate.

[0374] Embodiment 41. A method of printing on a substrate, the method comprising ink-jetting an ink formulation onto a print substrate by utilizing one or more print bars, each print bar comprising one or more printheads, thereby forming an ink image on the substrate, wherein the ink formulation is an aqueous ink-jet ink formulation as defined in any one of embodiments 1 to 32.

[0375]

[0071] Embodiment 42. A printing method comprising: providing an intermediate transfer member having a release layer surface; ink-jetting an ink formulation onto the release layer surface by utilizing one or more print bars, each print bar comprising one or more print heads, thereby forming an ink image on the release layer surface; and transferring said ink image from the intermediate transfer member to a print substrate; Including, 33. The method of claim 1, wherein the ink formulation is an aqueous inkjet ink formulation as described in any one of embodiments 1 to 32.

[0376]

[0081] Embodiment 43. The method of embodiment 42, further comprising substantially drying the ink image formed on the intermediate transfer member, and transferring the substantially dried ink image from the intermediate transfer member to a print substrate.

Claims

1. (a) A solvent containing water; (b) at least one coloring agent; and (c) at least one surfactant; A water-based inkjet ink formulation containing, The ink formulation has a dynamic surface tension of 37–50 mN / m (measured with a bubble lifetime of 0.015 seconds) and a static surface tension of 23.0–25.5 mN / m (measured with a bubble lifetime of 10 seconds), both of which were measured at room temperature (RT) using the bubble pressure method with a Sita bubble tension meter: Model Sita online (Pro-line T15); and The aqueous inkjet ink formulation wherein the at least one surfactant is selected to obtain the dynamic surface tension and the static surface tension.

2. The static surface tension of the ink formulation is further measured at room temperature (RT) at a frequency of 5 Hz using a standard liquid tensile meter and a Kruss force tensile meter (K20 model), and the static surface tension is 23.8 to 24.5 mN / m, as described in claim 1.

3. The aqueous inkjet ink formulation according to claim 1, wherein the at least one surfactant is a first type of surfactant and / or a second type of surfactant.

4. The aqueous inkjet ink formulation according to claim 3, wherein the first type of surfactant is a silicone surfactant.

5. The aqueous inkjet ink formulation according to claim 4, wherein the silicone surfactant is selected from the group consisting of polyether-modified polydimethylsiloxane, polyether-modified siloxane, siloxane-based gemini surfactant, and any combination thereof.

6. The silicone surfactant is i. The siloxane-based gemin surfactant is Tego 4100, and / or ii. The polyether-modified siloxane surfactant is selected from the group consisting of Byk349, Byk348, Byk-3455 and any combination thereof, and / or iii. The polyether-modified polydimethylsiloxane surfactant is BYK-3456. The aqueous inkjet ink formulation according to claim 5.

7. The silicone surfactant is a polyether-modified polydimethylsiloxane having at least four polyether-modified repeating units, and / or The silicone surfactant is a polyether-modified siloxane having at least four polyether-modified repeating units. The aqueous inkjet ink formulation according to claim 5.

8. The aqueous inkjet ink formulation according to claim 3, wherein the second type of surfactant is a non-silicone surfactant.

9. The aqueous inkjet ink formulation according to claim 8, wherein the non-silicone surfactant is Surfynol PSA336.

10. The aqueous inkjet ink formulation according to claim 1, wherein the at least one surfactant is a first type of surfactant selected from the group consisting of Tego 4100, Byk 349, Byk 348, Byk-3456, Byk-3455 and any combination thereof, and the ink formulation optionally further comprises at least one second type of surfactant which is Surfynol PSA.

11. The aqueous inkjet ink formulation according to claim 10, wherein the ink formulation further comprises at least one second type of surfactant which is Surfynol PSA.

12. The aqueous inkjet ink formulation according to claim 1, wherein the at least one surfactant is present in the aqueous inkjet ink formulation at a concentration of 0.1 w / w% to 3.0 w / w%.

13. The aforementioned formulation comprises at least one of the following i. At least one co-solvent; ii. At least one plasticizer; iii. At least one dispersant; iv. At least one rust inhibitor: v. At least one antimicrobial agent; vi. At least one wax material; vii. At least one gelling inhibitor; viiii. At least one pH control agent; ix. At least one antifoaming agent; x. The aqueous inkjet ink formulation according to claim 1, further comprising at least one binder.

14. A method for improving the printing process and improving the quality of the resulting printed image, wherein the method is: (a) A solvent containing water; (b) at least one coloring agent; and (c) at least one surfactant; Using a water-based inkjet ink formulation that includes: The ink formulation has a dynamic surface tension of 37–50 mN / m (measured with a bubble lifetime of 0.015 seconds) and a static surface tension of 23.0–25.5 mN / m (measured with a bubble lifetime of 10 seconds), both of which were measured at room temperature using the bubble pressure method with a Sita bubble tension meter: Model Sita online (Pro-line T15); and The method wherein the at least one surfactant is selected to obtain the dynamic surface tension and the static surface tension, thereby improving one or more of the printing process and the quality of the resulting printed image.

15. The method according to claim 14, wherein the aqueous inkjet ink formulation is the formulation described in claim 1 or 2.

16. A printing method utilizing the aqueous inkjet ink formulation described in claim 1 or 2.

17. A printing system comprising the aqueous inkjet ink formulation according to claim 1 or 2.

18. A printing system comprising an image forming station having one or more print bars, each print bar configured to hold an ink formulation, and comprising one or more print heads, each of the one or more print heads configured to spray the ink formulation onto a printing substrate to form an ink image on the substrate, wherein at least one of the one or more print bars is configured to hold the aqueous inkjet ink formulation according to claim 1 or 2.

19. It is a printing system: An intermediate transfer member having a release layer surface; An image forming station comprising one or more print bars, each print bar configured to hold an ink mixture, and comprising one or more print heads, each of the one or more print heads configured to spray the ink mixture onto the surface of the release layer to form an ink image thereon, wherein at least one of the one or more print bars is configured to hold the aqueous inkjet ink mixture; and A transfer station for transferring the aforementioned ink image from an intermediate transfer member to a printing substrate, The system according to claim 17, comprising:

20. The system according to claim 19, further comprising a drying station configured to substantially dry an ink image formed on an intermediate transfer member, wherein the transfer station is configured to transfer the substantially dried ink image from the intermediate transfer member to a printing substrate.

21. Printing method: To provide an intermediate transfer member having a release layer surface; By using one or more print bars, each equipped with one or more print heads, to inkjet an ink mixture onto the surface of the release layer, thereby forming an ink image on the surface of the release layer; and Transferring the aforementioned ink image from the intermediate transfer member to the printing substrate; Includes, The method wherein the ink formulation is the aqueous inkjet ink formulation according to claim 1 or 2.

22. The method according to claim 21, further comprising substantially drying an ink image formed on an intermediate transfer member, and transferring the substantially dried ink image from the intermediate transfer member to a printing substrate.

Images