Inkjet inks comprising amine-modified silicones

Abstract

An inkjet ink comprising (A) a terpene phenol resin, (B) a solvent system comprising (B1) ethanol and (B2) a co-solvent, and (C) an amine-modified silicone comprising a silicone backbone (main chain) and one or more organic amine side chains attached to the silicone backbone, the inkjet ink being characterized by a prolonged uncapping time and excellent adhesion to various substrates, a printed matter including the inkjet ink in dry form, and a method of forming a printed image with a thermal inkjet printhead are also provided.

Description

[0001] Cross - reference to related applications

[0002] This application claims priority to PCT Application No. PCT / US2002 / 051379, filed on November 30, 2022. Technical field

[0003] The present invention relates to solvent - based inkjet inks, particularly inkjet inks formulated with (A) terpene - phenolic resin, (B) a solvent system comprising (B1) ethanol and (B2) a co - solvent, and (C) an amine - modified silicone, wherein (C) the amine - modified silicone comprises: a silicone backbone (main chain), and one or more organic amine side chains attached to the silicone backbone. Background art

[0004] The "Background" description provided herein is for the purpose of presenting the context of the present disclosure generally. Within the scope of the description in this background art section, the work of the present inventors and aspects of the description that may not qualify as prior art at the time of filing are neither expressly nor implicitly admitted as prior art against the present invention.

[0005] Thermal inkjet (TIJ) printing is a desirable printing, coding, and marking technology because it provides high printing resolution at a lower cost than competing technologies in the art, such as continuous inkjet (CIJ) methods. During the thermal inkjet printing process, the print cartridge contains a series of tiny chambers, each of which contains a heater that generates ink droplets through the thermal evaporation of the ink solvent. During the ejection process, the resistor is rapidly heated to generate a bubble (hence the name "bubble jet"), and subsequently, the droplet is ejected from the orifice. This process is extremely efficient and repeatable, and modern TIJ print heads for industrial graphic applications are capable of generating uniform droplets with a volume of less than 4 pL at a frequency above 36 kHz.

[0006] However, industrial marking and coding often require printing basic information, such as personal information, labels, codes, dates (such as expiration dates), and traceability information (such as manufacturing batches), on substrates with complex surfaces. Substrates with complex surfaces include, for example, radially, curved, serrated, corrugated, grooved, and / or flanged substrates, or various different substrates, such as porous and non - porous substrates or substrates formed from materials with different physical and chemical properties. These different substrate characteristics can lead to different ink adhesion characteristics. If the ink does not adhere correctly to the substrate, the printed image quality will be poor. For many applications, poor image quality is unacceptable, but it is especially so for the marking and coding of basic information. Adding resin to the ink has been proposed as a means of improving adhesion.

[0007] However, after a period of inactivity in a system with added resin, thermal inkjet printing may be plagued by poor reliability. For example, some inkjet inks have a very short open time, and the loss of solvent due to long-term exposure to the air inside the open print head causes clogging of the print head nozzles, resulting in unreliable inkjet and degraded image quality over time.

[0008] Solvent-based inkjet inks are made using a specific combination of binder resins, modified silicones, and volatile organic solvents or solvent mixtures including ethanol and colorants. For example, WO2021176086 discloses an inkjet ink containing polyether-modified silicone and ethanol. However, this reference does not contain amine-modified silicone. SUMMARY OF THE INVENTION

[0009] In view of the above, there is a need for an inkjet ink that has an extended open time and adheres firmly to a plurality of substrates.

[0010] Accordingly, one object of the present invention is to provide a novel inkjet ink that meets these criteria.

[0011] Another object of the present disclosure is to provide a novel printed matter containing the inkjet ink in a dry form.

[0012] Another object of the present disclosure is to provide a new method for forming a printed image on a substrate by applying the inkjet ink to the substrate and drying it.

[0013] The inventors have found that a combination of terpene phenol resin, a solvent system containing ethanol and a co-solvent, and amine-modified silicone provides an inkjet ink characterized by an extended open time and excellent adhesion to substrates, thus achieving these and other objects, which will become apparent in the following detailed description.

[0014] Accordingly, the present invention provides:

[0015] (1) An inkjet ink, comprising:

[0016] (A) Terpene phenol resin;

[0017] (B) A solvent system comprising (B1) ethanol and (B2) a co-solvent; and

[0018] (C) Amine-modified silicone,

[0019] wherein the amine-modified silicone (C) includes a silicone backbone (main chain) and one or more organic amine side chains attached to the silicone backbone.

[0020] (2) The inkjet ink according to (1), wherein the terpene phenol resin (A) is a copolymer comprising a monoterpene segment and a phenol segment containing a phenolic compound, and wherein the phenol segment is linked to the monoterpene segment at at least one position selected from the ortho position relative to the phenolic hydroxyl group and the para position relative to the phenolic hydroxyl group.

[0021] (3) The inkjet ink according to (2), wherein

[0022] the monoterpene segment is at least one bicyclic monoterpene selected from 3-carene, α-pinene, β-pinene, and camphene; and

[0023] the phenolic compound is phenol.

[0024] (4) The inkjet ink according to any one of (1) to (3), wherein the hydroxyl value of the terpene phenol resin (A) is 10 to 75 mgKOH / g.

[0025] (5) The inkjet ink according to any one of (1) to (4), wherein, based on the total weight of the inkjet ink, the content of the terpene phenol resin (A) is 0.1 to 10 wt.%.

[0026] (6) The inkjet ink according to any one of (1) to (5), wherein the co-solvent (B2) is at least one selected from n-propanol, methyl ethyl ketone, ethyl acetate, propylene glycol monomethyl ether, and 1,3-dioxolane.

[0027] (7) The inkjet ink according to any one of (1) to (6), wherein the weight ratio of ethanol (B1) to the co-solvent (B2) ((B1):(B2)) is 1:1 to 25:1.

[0028] (8) The inkjet ink according to any one of (1) to (7), wherein the organic amine side chain is at least one selected from a monoamine containing a primary amine and a diamine containing a primary amine and a secondary amine.

[0029] (9) The inkjet ink according to any one of (1) to (8), wherein the amine-modified silicone (C) has a viscosity at 25 °C of 25 to 250 mm 2 / s.

[0030] (10) The inkjet ink according to any one of (1) to (9), wherein the amine functional group equivalent of the amine-modified silicone is 350 to 11000 g / mol.

[0031] (11) The inkjet ink according to any one of (1) to (10), wherein the content of the amine-modified silicone is 0.1 to 10 wt.%.

[0032] (12) The inkjet ink according to (1), which is substantially free of polyether-containing surfactants.

[0033] (13) An inkjet ink according to any one of (1) to (12), further comprising (D) an alkanolamine.

[0034] (14) The inkjet ink according to (13), wherein the content of the alkanolamine (D) is 0.01 to 5 wt.% based on the total weight of the inkjet ink.

[0035] (15) The inkjet ink according to (13), wherein the alkanolamine (D) is at least one selected from ethanolamine, propanolamine, isopropanolamine, diethanolamine, and triethanolamine.

[0036] (16) The inkjet ink according to any one of (1) to (15), further comprising (E) a colorant.

[0037] (17) The inkjet ink according to (16), wherein the colorant (E) is a metal complex azo dye.

[0038] (18) A printed matter, comprising:

[0039] A substrate and a dried form of the inkjet ink according to any one of (1) to (17) provided on the substrate.

[0040] (19) A method for forming a printed image on a substrate, the method comprising:

[0041] Applying the inkjet ink according to any one of (1) to (17) to the substrate with a thermal inkjet printhead; and

[0042] Drying the inkjet ink,

[0043] wherein the substrate is substantially free of amine-modified silicone. DESCRIPTION OF THE DRAWINGS

[0044] The above paragraphs are provided as a general introduction and are not intended to limit the scope of the appended claims. When considered in conjunction with the accompanying drawings, the described embodiments and further advantages will be best understood by reference to the following detailed description, wherein:

[0045] Figure 1 Shows the evaluation of alphanumeric printed inks, including a "good" rating (clear, readable, sharp and well-defined image), an "acceptable" rating (readable, mostly clear, some blurring or slight fuzziness at the edge contours), and a "bad" rating (unreadable, lack of clarity, ill-defined contours);

[0046] Figure 2Shows the adhesion evaluation of printed images by tape stripping test, including "good" rating (almost no ink on the tape; no change in printing), "acceptable" rating (obvious ink on the tape; obvious changes in printing, such as reticulation or fading), and "poor" rating (a large amount of ink on the tape; significant decline in printing quality, such as reticulation and fading). Detailed implementation

[0047] In the following description, it should be understood that other embodiments may be utilized and structural and operational changes may be made without departing from the scope of the present embodiments disclosed herein.

[0048] Unless otherwise specified, the phrase "substantially free of" describes that the amount of a specific component in the inkjet ink is less than 1 wt.%, preferably less than 0.5 wt.%, more preferably less than 0.1 wt.%, even more preferably less than 0.05 wt.%, and still more preferably 0 wt.% relative to the total weight of the inkjet ink.

[0049] As used herein, the term "optional" or "optionally" means that the subsequent described event may or may not occur, or the subsequent described component may or may not be present (e.g., 0 wt.%).

[0050] Unless otherwise specified, the term "alkyl" as used herein refers to a straight-chain, branched-chain or cyclic aliphatic chain segment having at least 1, preferably at least 2, preferably at least 3, preferably at least 4 carbon atoms, and at most 22, preferably at most 20, preferably at most 18, preferably at most 12, preferably at most 8 carbon atoms. Examples of alkyl include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, isopentyl, neopentyl, hexyl, isohexyl, 3-methylpentyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, lauryl, myristyl, cetyl, stearyl, etc., including Guerbet-type alkyls (e.g., 2-methylpentyl, 2-ethylhexyl, 2-propylheptyl, 2-butyl octyl, 2-pentyl nonyl, 2-hexyl decyl, 2-heptyl undecyl, 2-octyl dodecyl, 2-nonyl tridecyl, 2-decyl tetradecyl, and 2-undecyl pentadecyl). Cycloalkyl is a cyclized alkyl. Exemplary cycloalkyls include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, norbornyl, and adamantyl.

[0051] As used herein, the term "fat" describes a compound having a long-chain (linear) hydrophobic moiety composed of hydrogen and 8 to 22 carbon atoms anywhere, which may be fully saturated or partially unsaturated.

[0052] As used herein, the term "aryl" refers to an aromatic group containing only carbon in an aromatic ring, such as phenyl, biphenyl, naphthyl, anthracenyl, etc.

[0053] As used herein, the term "arylalkyl" refers to a straight-chain, branched-chain, or cycloalkyl moiety (as defined above) substituted with an aryl group (as described above), where the aryl group itself may optionally be substituted with an alkyl group, and examples thereof include, but are not limited to, benzyl, phenethyl, 3-phenylpropyl, 2-phenylpropyl, 1-phenylpropyl, 4-phenylbutyl, 3-phenylbutyl, 2-phenylbutyl, -2-methylbenzyl, 3-methylbenzyl, 4-methylbenzyl, 2,4-dimethylbenzyl, 2-(4-ethylphenyl)ethyl, 3-(3-propylphenyl)propyl, and the like.

[0054] As used herein, the term "fat" describes a compound having a long-chain (linear) hydrophobic moiety consisting of hydrogen and from 8 to 22 carbon atoms anywhere, which may be fully saturated or partially unsaturated.

[0055] The term "(meth)acrylate" is used herein to refer to acrylate and methacrylate groups. In other words, this term should be construed as "methyl" being optional. Further, the term "(meth)acrylate" is generally used to refer to acrylic-based compounds and acrylate-based compounds.

[0056] Throughout the specification, the term "boiling point" (b.p.) refers to the boiling point of a liquid measured at sea-level atmospheric pressure (i.e., 760 mmHg or 1 atmosphere), also known as the normal boiling point, unless otherwise specified.

[0057] The term "open cap behavior" as used herein refers to the ability of an inkjet ink to be easily ejected from a printhead after long-term exposure to air. The "open cap time" of an inkjet ink refers to the amount of time that an inkjet printhead may remain uncapped before the printer nozzles no longer eject properly, which may be due to blockage or clogging during print recovery. Generally, due to the loss of solvent inside and / or around any nozzle, ink crusting, and / or fouling of various ink components, the nozzles may become blocked (i.e., impeded, slowed down) or clogged (i.e., blocked, substantially or completely closed) by a viscous plug formed in the nozzle. If the nozzle is blocked, the ink droplets ejected through the nozzle orifice may be misdirected, which may adversely affect print quality. When the orifice is clogged, it becomes substantially or completely blocked. Due to the nozzle being clogged, ink droplets may not pass through the affected nozzle. Thus, the criterion for measuring that a nozzle cannot eject is that the ink is misdirected to a greater or lesser extent through the nozzle orifice, or is completely blocked, which can be measured by visually inspecting the printed image.

[0058] The term "meshing" refers to a printing defect characterized by the detachment of the ink film from certain parts of the substrate due to the incompatibility between the inkjet ink and the substrate surface. Meshing typically results in an "orange peel" or "pinhole" effect in the image.

[0059] Inkjet ink

[0060] The present disclosure relates to an inkjet ink which has appropriate physical and chemical stability both at ambient temperature and at the printhead operating temperature, is reliable in jetting, has good adhesion to porous and non-porous substrates, and can dry rapidly after being applied to the substrate while having an extended open time.

[0061] The inkjet ink of the present disclosure generally contains the following components: (A) a terpene phenol resin, (B) a solvent system containing (B1) ethanol and (B2) a co-solvent, and (C) an amine-modified silicone.

[0062] The inkjet ink of the present disclosure may also optionally contain one or more of (D) an alkanolamine and (E) a colorant.

[0063] (A) Resin

[0064] In a preferred embodiment, the terpene phenol resin (A) used in the inkjet ink is a copolymer containing a monoterpene segment and a phenolic compound segment, wherein the terpene phenol resin (A) is a copolymer containing a monoterpene segment and a phenolic chain segment containing a phenolic compound, and wherein the phenolic chain segment is connected to the monoterpene segment at at least one position selected from the ortho position relative to the phenolic hydroxyl group and the para position relative to the phenolic hydroxyl group.

[0065] The terpene phenol resin (A) is a copolymerization reaction product obtained by alkylating one or more phenolic compounds with one or more terpenes, and has been used in inks and adhesives to provide a tackifying effect. As is known to those of ordinary skill in the art, such a resin can be easily obtained by copolymerization of phenol and terpene monomers under the catalytic action of a strong acid, a metal salt having a condensation effect, bleaching earth, a Friedel-Craft catalyst (such as boron trifluoride). In addition to the structural units derived from phenolic compounds and the structural units derived from terpenes, the copolymerization reaction product may also have other structural units. That is, the terpene phenol resin (A) contains units derived from terpene units and phenolic units.

[0066] Based on the total weight (100 wt.%) of the structural units of the copolymerization reaction product, the amount of other structural units other than terpenes and phenols is preferably less than 5 wt.%, preferably less than 3 wt.%, preferably less than 1 wt.%, preferably substantially 0 wt.%, and preferably 0 wt.%.

[0067] The terpene phenol resin (A) used herein can be based on any terpene having at least one ethylenic double bond capable of being alkylated by a phenolic compound. Terpenes have a basic skeleton (C5H8) p , where p is a positive integer, describing the number of isoprene units bonded continuously from beginning to end. For example, hemiterpene (p = 1) has a C5H8 skeleton, monoterpene (p = 2) has a C10 H 16 skeleton, sesquiterpenes (p = 3) have C 15 H 24 skeleton, and so on.

[0068] In some embodiments, the terpene phenol resin (A) is based on monoterpene monomer units. The monoterpene can be a linear monoterpene (such as myrcene, ocimene, etc.), a monocyclic monoterpene (such as limonene, γ-terpinene, α-phellandrene, β-phellandrene, terpinolene, etc.) or a bicyclic monoterpene (such as 3-carene, α-pinene, β-pinene, α-fenchene, camphene, etc.), including their various stereoisomers and mixtures thereof. In a preferred embodiment, the monoterpene is a bicyclic monoterpene, particularly preferably 3-carene, α-pinene, β-pinene and camphene, and more preferably α-pinene and / or β-pinene.

[0069] The phenolic compound has at least one hydroxyl group directly bonded to the benzene ring. All mono- or poly-phenolic compounds can be used to prepare the terpene phenol resin described herein, provided that the phenolic compound has at least two replaceable hydrogen atoms at the ortho and / or para positions relative to at least one hydroxyl group. That is to say, the phenolic compound should be able to be polyalkylated (such as dialkylated) with terpenes, and thus should have at least two available ortho / para positions for alkylation relative to at least one hydroxyl group.

[0070] In a preferred embodiment, the phenolic compound is phenol, which is considered as the parent unsubstituted phenolic compound (i.e., containing one hydroxyl group directly bonded to the benzene ring and no other substitutions). Alternatively, in addition to the phenolic hydroxyl group, the phenolic compound can be substituted at up to three positions, where one, two or three aromatic hydrogens of phenol are substituted by an equal number of substituents, each substituent independently selected from hydroxyl; C1-C 22 alkyl, preferably C2-C 18 alkyl, more preferably C3-C 12 alkyl, even more preferably C4-C9 alkyl, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl; C1-C 22 alkoxy, preferably C2-C 12 alkoxy, more preferably C3-C6 alkoxy, such as methoxy, ethoxy and isopropoxy; aryl; arylalkyl, such as benzyl; halogen groups, such as chlorine, bromine, fluorine and iodine.

[0071] Specific examples of the substituted phenolic compounds include, but are not limited to, o-cresol, m-cresol, p-cresol, 2,5-xylenol, 2,3-xylenol, 3,4-xylenol, 3,5-xylenol, 2,3,5-trimethylphenol, isopropylphenol (such as 4-isopropylphenol), tert-butylphenol (such as 4-tert-butylphenol), amylphenol (such as 4-tert-amylphenol), heptylphenol (such as 4-heptylphenol), octylphenol (such as o-octylphenol, p-octylphenol, etc.), nonylphenol (such as 4-(2,4-dimethylhept-3-yl)phenol), decylphenol, dodecylphenol, diphenylolpropane (bisphenol A), phenylphenol (such as 3-phenylphenol), cumylphenol, p-methoxyphenol, benzyloxyphenol, guaiacol, ethoxyphenol (such as 4-ethoxyphenol), and polyphenolic compounds such as resorcinol, pyrogallol, catechol, and hydroquinone, including mixtures of any two or more of the above. Also included are polycyclic phenols such as naphthol (such as 1-naphthol, 2-naphthol, etc.) and similar compounds.

[0072] In a preferred embodiment, the terpene phenol resin (A) used in the inkjet ink is a copolymer containing a monoterpene segment, where the monoterpene segment is at least one bicyclic monoterpene selected from 3-carene, α-pinene, β-pinene, and camphene; and the phenolic compound is phenol.

[0073] In a more preferred embodiment, the terpene phenol resin (A) used in the inkjet ink is a copolymer containing a monoterpene segment, where the monoterpene segment is at least one bicyclic monoterpene selected from an α-pinene segment and a phenol segment.

[0074] Based on the total weight of the inkjet ink, the content of the terpene phenol resin (A) in the inkjet ink can be at least 0.1 wt.%, preferably at least 0.2 wt.%, more preferably at least 0.3 wt.%, even more preferably at least 0.4 wt.%, even more preferably at least 0.5 wt.%, and preferably at most 10 wt.%, more preferably at most 7.5 wt.%, even more preferably at most 5 wt.%, even more preferably at most 2.5 wt.%, further more preferably at most 2.0 wt.%, still more preferably at most 1.5 wt.%, yet more preferably at most 1 wt.%, even more preferably at most 0.9 wt.%.

[0075] The molecular weight of the terpene phenol resin (A) can vary depending on factors such as the monomers used and the reaction conditions, but generally, a terpene phenol resin (A) with a weight average molecular weight of at least 200 g / mol, preferably at least 500 g / mol, more preferably at least 600 g / mol, even preferably at least 700 g / mol, and at most 3000 g / mol, preferably at most 2500 g / mol, more preferably at most 2000 g / mol, even more preferably at most 1500 g / mol is used.

[0076] The hydroxyl value (OHV) is defined as the number of milligrams of potassium hydroxide required to neutralize the acetic acid absorbed when one gram of a chemical substance containing free hydroxyl groups is acetylated. Thus, the measurement of the hydroxyl value or relative hydroxyl content of the terpene phenol resin (A) is directly related to the content of phenolic compounds in the terpene phenol resin (A), where a higher hydroxyl value indicates a higher incorporation of phenolic compounds (and a lower incorporation of terpenes) in the copolymer. The hydroxyl value can be determined in accordance with Japanese Industrial Standard JIS K 0070:1992, "Test Methods for Acid Value, Saponification Value, Ester Value, Iodine Value, Hydroxyl Value and Unsaponifiable Matter of Chemical Products".

[0077] The hydroxyl value of the terpene phenol resin (A) used in the disclosed inkjet inks can vary. However, generally, those hydroxyl values are preferably at least 10 mgKOH / g, preferably at least 12.5 mgKOH / g, more preferably at least 15 mgKOH / g, preferably at least 17.5 mgKOH / g, preferably at least 20 mgKOH / g, and preferably at most 75 mgKOH / g, preferably at most 72.5 mgKOH / g, preferably at most 70 mgKOH / g, preferably at most 67.5 mgKOH / g, preferably at most 65 mgKOH / g, preferably at most 62.5 mgKOH / g, more preferably at most 60 mgKOH / g, even more preferably at most 55 mgKOH / g, even more preferably at most 50 mgKOH / g, even more preferably at most 45 mgKOH / g, even more preferably at most 40 mgKOH / g, more preferably at most 35 mgKOH / g. Suitable examples of such terpene phenol resins (A) include, but are not limited to, U130 POLYSTER (OHV = 25 mgKOH / g), U115 POLYSTER (OHV = 30 mgKOH / g), T160 POLYSTER (OHV = 60 mgKOH / g), T145 POLYSTER (OHV = 65 mgKOH / g) available from Yasuhara Chemical Co., Ltd., and DERTOPHENE T (OHV = 40 mgKOH / g), DERTOPHENE T160 (OHV = 60 mgKOH / g), and DERTOPHENE T105 (OHV = 30 mgKOH / g) available from Pinova.

[0078] In addition to the terpene phenol resin (A), the inkjet ink may optionally contain a terpene resin. The terpene resin may include small amounts of other structural units, in addition to phenol as a structural unit that can copolymerize with the terpene.

[0079] Based on the total weight of the inkjet ink, the content of this terpene resin can be at least 0.1 wt.%, preferably at least 0.5 wt.%, preferably at least 1 wt.%, more preferably at least 1.5 wt.%, even more preferably at least 2 wt.%, still further preferably at least 2.5 wt.%, and at most 10 wt.%, preferably at most 9 wt.%, preferably at most 8 wt.%, preferably at most 7 wt.%, preferably at most 6 wt.%, more preferably at most 5 wt.%, even more preferably at most 4 wt.%, still more preferably at most 3 wt.%.

[0080] Terpene resin refers to an oligomer or polymer having at least 95 wt.%, preferably at least 96 wt.%, more preferably at least 97 wt.%, more preferably at least 98 wt.%, more preferably at least 99 wt.%, even more preferably at least 99.5 wt.%, still even more preferably 100 wt.% of structural units derived from polymerizable terpenes, based on the total structural units (100 wt.%) of the terpene resin. Terpenes have a basic skeleton (C5H8) p , where p is a positive integer, describing the number of isoprene units bonded continuously from start to end. For example, hemiterpenes (p = 1) have a C5H8 skeleton, monoterpenes (p = 2) have a C 10 H 16 skeleton, sesquiterpenes (p = 3) have a C 15 H 24 skeleton, and so on.

[0081] Exemplary terpene resins can be based on monoterpene monomer units. Monoterpenes can be acyclic monoterpenes (such as myrcene, ocimene, etc.), monocyclic monoterpenes (such as limonene, γ-terpinene, α-phellandrene, β-phellandrene, terpinolene, etc.) or bicyclic monoterpenes (such as 3-carene, α-pinene, β-pinene, α-fenchene, camphene, etc.), including their various stereoisomers and mixtures thereof. Monoterpenes can be monocyclic monoterpenes, such as limonene. Monoterpenes can be bicyclic monoterpenes, such as 3-carene, α-pinene, β-pinene, and camphene.

[0082] As is known to those of ordinary skill in the art, such terpene resins can be readily obtained, for example, by catalytic polymerization / oligomerization (in solution) of α-pinene monomers, which are typically derived from the fractionation of gum and sulfate turpentine obtained from pine trees, such as Pistacia terebinthus, Pinus pinaster, Pinus halepensis, Pinus massoniana, Pinus merkusii, Pinus palustris, Pinus taeda, and Pinus ponderosa.

[0083] The terpene resin can be a homopolymer prepared from α-pinene. Based on the total structural units of the terpene resin (100 wt.%), the α-terpene content (structural units derived from α-pinene) is at least 95 wt.%, preferably at least 96 wt.%, preferably at least 97 wt.%, preferably at least 98 wt.%, preferably at least 99 wt.%, more preferably at least 99.5 wt.%, even more preferably at least 99.9 wt.%, still more preferably 100 wt.%. The terpene resin can be a homopolymer prepared from β-pinene. Based on the total structural units of the terpene resin (100 wt.%), the β-terpene content (structural units derived from β-terpene) is at least 95 wt.%, preferably at least 96 wt.%, preferably at least 97 wt.%, preferably at least 98 wt.%, preferably at least 99 wt.%, more preferably at least 99.5 wt.%, even more preferably at least 99.9 wt.%, still more preferably 100 wt.%.

[0084] Generally, the number average molecular weight (M n ) of the terpene resin used in the inkjet ink is at least 330 g / mol, preferably at least 340 g / mol, preferably at least 400 g / mol, preferably at least 450 g / mol, preferably at least 500 g / mol, preferably at least 550 g / mol, preferably at least 600 g / mol, more preferably at least 650 g / mol, even more preferably at least 700 g / mol, still even more preferably at least 750 g / mol, and at most 1500 g / mol, preferably at most 1300 g / mol, preferably at most 1100 g / mol, preferably at most 1000 g / mol, more preferably at most 900 g / mol, even more preferably at most 800 g / mol, still even more preferably at most 790 g / mol.

[0085] Terpene resins can be in solid or liquid form at room temperature. When in solid form, the terpene resins used can be classified according to their softening point (SP), for example, according to the ring and ball softening point method. The ring and ball softening point is defined as the temperature at which, when the sample is heated in a glycerol bath at a specified rate, the sample disk held within a horizontal ring is depressed 1 inch (25.4 mm) under the weight of a steel ball. For example, the ring and ball softening point can be determined according to JIS B7410, the entire content of which is incorporated herein by reference. Measuring device: Automatic ring and ball softening point; Tester: ASP-MGK2, manufactured by MEITECH Company Limited; Heating rate: 5 °C / min; Starting temperature for heating: 40 °C; Measuring solvent: Glycerol. Terpene resins with various softening points can be used herein, for example, the softening point is at least 20 °C, preferably at least 22 °C, more preferably at least 24 °C, preferably at least 26 °C, preferably at least 28 °C, preferably at least 30 °C, preferably at least 40 °C, preferably at least 50 °C, preferably at least 60 °C, preferably at least 80 °C, preferably at least 100 °C, preferably at least 110 °C, preferably at least 115 °C, more preferably at least 120 °C, even more preferably at least 125 °C, still even more preferably at least 130 °C, and at most 160 °C, preferably at most 155 °C, preferably at most 150 °C, preferably at most 145 °C, more preferably at most 140 °C, even more preferably at most 138 °C, still even more preferably at most 135 °C. In a preferred embodiment, the softening point of the terpene resin is at least 20 °C, preferably at least 22 °C, more preferably at least 24 °C, and at most 50 °C, preferably at most 45 °C, preferably at most 40 °C, more preferably at most 35 °C, even more preferably at most 30 °C, still even more preferably at most 28 °C.

[0086] The bromine value is the number of grams of bromine (Br2) absorbed by 100 grams of the sample and is an indicator of the unsaturation of the sample. In some embodiments, the bromine value of the terpene resin used in the inkjet ink is at least 12, preferably at least 15, preferably at least 19, preferably at least 22, more preferably at least 25, even more preferably at least 26, still more preferably at least 27, and at most 35, preferably at most 34, preferably at most 33, more preferably at most 32, even more preferably at most 31, still more preferably at most 30. However, terpene resins with bromine values higher or lower than these values (such as hydrogenated terpene resins) can also be used in the disclosed inkjet inks.

[0087] The inkjet inks of the present disclosure can be formulated with a single type of terpene resin or a combination of two or more terpene resins. Examples of terpene resins that can be used in the inkjet inks herein, whether used alone or in combination, include but are not limited to PICCOLYTE A115 (ring and ball SP = 112 - 118 °C, bromine value = 31.5), PICCOLYTE A125 (ring and ball SP = 122 - 128 °C, bromine value = 31.5), PICCOLYTE A135 (ring and ball SP = 132 - 138 °C, bromine value = 27), PICCOLYTE A135PLUS (ring and ball SP = 132 - 138 °C), PICCOLYTE AO PLUS (liquid oligomer), PICCOLYTE A25 (ring and ball SP = 22 - 28 °C), and PINOVA RESIN 2495 (ring and ball SP = 132 - 138 °C, bromine value = 27), all made from high-purity α-pinene and available from PINOVA, and PICCOLYTE S25 (made from high-purity β-pinene, ring and ball SP = 22 - 28 °C, bromine value 19) available from PINOVA.

[0088] In addition to the terpene phenolic resin (A), the inkjet ink may optionally contain other binder resins / tackifiers / adhesive substances. Based on the total weight of the inkjet ink, the content of such other binder resins / tackifiers / adhesive substances can be at least 0.1 wt.%, preferably at least 0.5 wt.%, preferably at least 1 wt.%, more preferably at least 1.5 wt.%, even more preferably at least 2 wt.%, still more preferably at least 2.5 wt.%, and at most 10 wt.%, preferably at most 9 wt.%, preferably at most 8 wt.%, preferably at most 7 wt.%, preferably at most 6 wt.%, more preferably at most 5 wt.%, even more preferably at most 4 wt.%, still more preferably at most 3 wt.%. Such additional resin, binder, tackifier, or adhesive substance can include but are not limited to,

[0089] - Rosin resins, such as rosin resins derived from gum rosin, wood rosin, and tall oil rosin (the main components of which are resin acids, such as abietic acid, palustric acid, neoabietic acid, pimaric acid, isopimaric acid, and / or dehydroabietic acid), including rosin resins formed by modifying the above-mentioned rosin by esterification, hydrogenation (including partial hydrogenation), dimerization, and / or other modification / functionalization (e.g., by Diels-Alder reaction with unsaturated dibasic acids / anhydrides such as maleic acid or fumaric acid, reduction of carboxylic acids to corresponding aldehydes / alcohols, double bond isomerization, dehydrogenation, oxidation, disproportionation, etc.). Exemplary rosin resins include, but are not limited to, (1) rosin ester resins, such as rosin esters mainly composed of abietylenic or pimaric resin acids, which have been reacted with alcohols (such as glycerol, pentaerythritol, ethylene glycol, diethylene glycol, triethylene glycol, methanol, etc.) and optionally hydrogenated or partially hydrogenated, specifically mentioned are HARIESTER products available from Harima Chemicals, Inc., STAYBELITEESTER 10-E and PERMALYN 6110 available from Eastman, SUPERESTER A-125, SUPER ESTER A-75, PENSEL D-125, PINECRYSTAL KE-359 available from Arakawa Chemical Industries, Ltd., and FORAL 85, FORAL 105, HERCOLYN products, PEXALYN products, and PENTALYN products available from Pinova; (2) hydrogenated acidic rosins, such as FORAL AX and FORAL DX available from Pinova; (3) partially hydrogenated acidic rosins, such as STAYBELITE RESIN-E available from Eastman, and STAYBELITE and STAYBELITE A available from PINOVA; (4) dimerized rosins, such as POLY-PALE partially dimerized rosin available from Eastman; and (5) functionalized rosin resins, such as esters (e.g., glycerol esters) of rosin modified with maleic anhydride or rosins subjected to carboxylic acid reduction conditions, specifically mentioned are LEWISOL 28-M and Abitol-E hydrogenated abietyl alcohol available from Eastman;

[0090] - Phenolic resins (i.e., copolymers of phenolic compounds and formaldehyde), such as novolak resins available from DIC Corp., such as PHENOLITE TD-2131 and PHENOLITE TD-2090;

[0091] - Polyamide resins, such as VERSAMID 725, 744, 756, 759 available from BASF Japan Ltd., TOHMIDE 90, 92, 394-N available from Sanho Chemical Co., Ltd., and SUNMIDE 550, 554, 615A, 638, 640 available from Evonik;

[0092] - Epoxy resins, which include sulfonamide-modified epoxy resins, such as AD-PROMTS available from Rit Chem;

[0093] -(Meth)acrylate and styrene / (meth)acrylate resins, such as JONCRYL 63, JONCRYL 67, JONCRYL 586, JONCRYL 611, JONCRYL 682, JONCRYL 693 available from BASF, PARALOID DM-55 and PARALOID B-66 available from PalmerHolland, PARALOID B-72 available from Dow Chemical, USA, and ELVACITE 2013 available from Lucite Co., Ltd.;

[0094] - Polyurethane resins, such as those formed by the reaction between (i) polyols (including but not limited to ethylene glycol, propylene glycol, propanediol, butanediol, polyethylene glycol, polypropylene glycol, polytetrahydrofuran glycol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, polyester polyols (such as polyethylene glycol adipate diol, polyethylene glycol succinate diol, poly(3-methyl-1,5-pentanediol adipate) diol, poly(3-methyl-1,5-pentanediol terephthalate) diol, carbonate polyol) and (ii) diisocyanates (including but not limited to 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4-diphenylmethane diisocyanate, hexamethylene diisocyanate and isophorone diisocyanate); for example, PERMAX 200, PERMAX 202 and SANCURE 20025F available from Lubrizol;

[0095] - Polyvinyl butyral resins, such as PIOLOFORM BN 16 and MOWITAL B20H available from Kuraray America, Inc.;

[0096] - Polyhydroxystyrene resins, such as poly(p-hydroxystyrene) from DuPont;

[0097] - Vinyl resins, such as UCAR VYHH, VMCH, VMCA, and VAGF available from Dow Chemical Company, and VINNOL E15 / 45, H14 / 36, E15 / 45M, and E16 / 40A available from Wacker Chemie AG of Germany;

[0098] - Formaldehyde resins, which include sulfamide-modified formaldehyde resins such as p-toluenesulfonamide formaldehyde resin, melamine formaldehyde resin, and sulfamide-modified melamine formaldehyde resin;

[0099] - Cellulose ester resins, such as cellulose acetate butyrate (CAB-551-0.01) available from Eastman;

[0100] - And polyesters, sulfonated polyesters, gums, cellulose ethers, nitrocellulose resins, poly(maleic anhydride), acetal polymers, styrene / butadiene copolymers, ketone aldehyde resins, and polyketone resins;

[0101] - Including mixtures thereof, etc.

[0102] In some embodiments, the inkjet ink is substantially free of terpene resins. In some embodiments, except for terpene phenol resin (A) and any optional terpene resins, the inkjet ink is substantially free of additional binder resins / tackifiers / adhesive substances such as those described above. In some embodiments, terpene phenol resin (A) is the only resin present in the disclosed inkjet ink. In some embodiments, the inkjet ink is substantially free of rosin resins. In some embodiments, the inkjet ink is substantially free of rosin ester resins, partially hydrogenated acidic rosin, dimerized rosin, and other functionalized / modified rosin resins. In some embodiments, the inkjet ink is substantially free of phenolic resins. In some embodiments, the inkjet ink is substantially free of polyamide resins. In a preferred embodiment, terpene phenol resin (A) is the only tackifier or binder resin present in the inkjet ink.

[0103] It has been found that when used in combination with a solvent system (B) comprising ethanol (B1) and a co-solvent (B2) and an amine-modified silicone, terpene phenol resin (A) provides excellent open time and adhesion. Without being bound by theory, it is believed that terpene phenol resin (A) improves the open behavior of the inkjet ink by forming a thin "skin" or film covering within the printhead nozzles, thereby forming a temporary seal to prevent or reduce solvent loss during inactivity, but the "skin" easily breaks once the printing operation resumes. The polarity of terpene phenol resin (A) is considered to be high enough to dissolve the carrier but not so high as to inhibit "skin" formation due to too strong an interaction with the solvent system.

[0104] (B) Solvent system

[0105] In many printing processes using solvent-based inks, especially in thermal inkjet printing, the selection of a suitable solvent system can affect the reliability of the printing process, the performance / appearance of the printed ink product, and the overall printing process efficiency. For example, in thermal inkjet printing, the selection of the solvent system can 1) help form bubbles during the ejection process, thus enabling reliable inkjetting, 2) affect the stability / volatility of the inkjet ink by changing the interaction kinetics between the solvent and various inkjet ink components, thereby affecting the capping behavior, fouling, running stability, and / or droplet trajectory, 3) affect the adhesion, rub resistance, scratch resistance, and optical density characteristics of the printed image through the interaction forces between the solvent system and other inkjet ink components, even though the solvent may no longer be present or may be present in a smaller amount after drying, 4) affect the drying time after coating or the equipment required to dry the coated ink and / or 5) impact droplet kinetics.

[0106] In view of the above, inkjet inks having a solvent system (B) comprising (B1) ethanol and (B2) a co-solvent are particularly preferred herein. Examples of suitable co-solvents include, but are not limited to,

[0107] - Alcohols other than ethanol, such as 1-propanol, 2-propanol, 1-butanol, 2-butanol, tert-amyl alcohol, 2-methyl-1-butanol, undecanol (such as 1-undecanol), dodecanol (e.g., 1-dodecanol), tridecanol (e.g., 1-tridecanol), tetradecanol (e.g., 1-tetradecanol), including terpene alcohols, such as monoterpene alcohols (such as terpineol, geraniol, citronellol, linalool, etc.);

[0108] - Ketones, such as acetone, methyl ethyl ketone, diethyl ketone, diphenyl ketone, dibenzyl ketone, acetophenone, cyclopentanone, methyl isopropyl ketone, methyl n-propyl ketone, ethyl isopropyl ketone (also known as 2-methyl-3-pentanone), 2-hexanone (also known as methyl butyl ketone), methyl isobutyl ketone, 3-hexanone, 3-pentanone, 2-pentanone, cyclohexanone, and diacetone alcohol;

[0109] - Ethers, such as dimethyl ether, diethyl ether, dipropyl ether, methyl tert-butyl ether, tetrahydrofuran, 1,4-dioxane, dibutyl ether, and di-tert-butyl ether;

[0110] - Ethylene glycol ethers, including monoalkyl ethylene glycol ethers, dialkyl ethylene glycol ethers, and monoalkyl monoester ethylene glycol ethers, etc., such as ethylene glycol monomethyl ether (2-methoxyethanol), ethylene glycol monoethyl ether (2-ethoxyethanol), ethylene glycol monoisopropyl ether (2-isopropoxyethanol), ethylene glycol monon-propyl ether (2-propoxyethanol), ethylene glycol monotert-butyl ether, ethylene glycol monobutyl ether, ethylene glycol mono-isobutyl ether, ethylene glycol monophenyl ether (2-phenoxyethanol), ethylene glycol monobenzyl ether (2-benzyloxyethanol), diethylene glycol monomethyl ether (2-(2-methoxyethoxy)ethanol), diethylene glycol monoethyl ether (2-(2-ethoxyethoxy)ethanol), propylene glycol monomethyl ether (1-methoxy-2-propanol), propylene glycol monoethyl ether, propylene glycol monotert-butyl ether, propylene glycol monon-propyl ether, propylene glycol monoisopropyl ether, propylene glycol monon-butyl ether, dipropylene glycol monomethyl ether, propylene glycol methyl ether acetate, ethylene glycol dimethyl ether (dimethoxyethane), ethylene glycol diethyl ether (diethoxyethane), diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol monon-propyl ether;

[0111] - Esters, such as methyl acetate, ethyl acetate, n-butyl acetate, methyl lactate, ethyl lactate, butyl lactate, methoxyethyl acetate, ethoxyethyl acetate, methoxypropyl acetate, and ethoxypropyl acetate;

[0112] - Acetals, such as 1,3-dioxolane;

[0113] - Amides, such as dimethylformamide and dimethylacetamide;

[0114] - Acetonitrile;

[0115] - And mixtures of two or more of them.

[0116] In some embodiments, the solubility parameter of the co-solvent (B2) is preferably less than 16.5 (cal / cm 3 ) 1 / 2 , preferably less than 16 (cal / cm 3 ) 1 / 2 , preferably less than 15 (cal / cm 3 ) 1 / 2 , preferably less than 14 (cal / cm 3 ) 1 / 2 , preferably less than 13.5 (cal / cm 3 ) 1 / 2 , preferably less than 13.0 (cal / cm 3 ) 1 / 2 , preferably less than 12.5 (cal / cm 3 ) 1 / 2 , preferably less than 12 (cal / cm 3 ) 1 / 2 .

[0117] In some embodiments, the preferred co-solvent (B2) is selected from n-propanol (solubility parameter 12.0 (cal / cm 3 )) 1 / 2 ), methyl ethyl ketone (solubility parameter 9.0 (cal / cm 3 )) 1 / 2 ), ethyl acetate (solubility parameter 9.1 (cal / cm 3 )) 1 / 2 ), propylene glycol monomethyl ether (solubility parameter 11.2 (cal / cm 3 )) 1 / 2 ), and 1,3-dioxolane (solubility parameter 8.6 (cal / cm 3 )) 1 / 2 ), and is at least one of them.

[0118] In some embodiments, the solvent system is substantially free of 1-methoxy-2-propanol. In some embodiments, the solvent system is substantially free of butyl propionate.

[0119] Based on the total weight of the inkjet ink, the amount of ethanol (B1) preferably used to obtain the desired ink properties (such as open cap behavior, adhesion, etc.) can be at least 50 wt.%, preferably at least 55 wt.%, preferably at least 60 wt.%, preferably at least 65 wt.%, preferably at least 70 wt.%, preferably at least 75 wt.%, preferably at least 80 wt.%, and at most 98 wt.%, preferably at most 97 wt.%, preferably at most 96 wt.%, more preferably at most 94 wt.%, even more preferably at most 92 wt.%, still more preferably at most 90 wt.%, still even more preferably at most 88 wt.%.

[0120] Based on the total weight of the inkjet ink, the content of the co-solvent (B2) in the inkjet ink can be at least 0.5 wt.%, preferably at least 1 wt.%, preferably at least 2 wt.%, preferably at least 3 wt.%, preferably at least 4 wt.%, preferably at least 5 wt.%, more preferably at least 6 wt.%, more preferably at least 7 wt.%, more preferably at least 8 wt.%, and at most 45 wt.%, preferably at most 40 wt.%, preferably at most 35 wt.%, preferably at most 30 wt.%, preferably at most 25 wt.%, more preferably at most 20 wt.%, even more preferably at most 18 wt.%, even more preferably at most 16 wt.%, still more preferably at most 15 wt.%.

[0121] In a preferred embodiment, ethanol (B1) and a co-solvent (B2) together constitute a major part of the solvent system (B) used in the inkjet ink, that is, based on the total weight of the solvent system (B), the combined weight of ethanol (B1) and the co-solvent (B2) can be in the range of at least 50 wt.%, preferably at least 60 wt.%, more preferably at least 70 wt.%, preferably at least 80 wt.%, preferably at least 90 wt.%, preferably at least 95 wt.%, preferably at least 96 wt.%.

[0122] Relative to ethanol (B1), preferred inkjet inks are those in which the weight ratio of ethanol (B1) to the co-solvent (B2) ((B1):(B2)) is from 1:1, more preferably from 1.25:1, more preferably from 1.5:1, more preferably from 1.75:1, more preferably from 2:1, more preferably from 3:1, more preferably from 4:1, to preferably at most 25:1, more preferably at most 22.5:1, more preferably at most 20:1, more preferably at most 17.5:1, more preferably at most 15:1, more preferably at most 12.5:1, more preferably at most 11:1, more preferably at most 9:1.

[0123] Relative to the terpene phenol resin (A), preferred inkjet inks are those in which the weight ratio of ethanol (B1) to the terpene phenol resin (A) ((B1):(A)) is from at least 20:1, preferably at least 25:1, preferably at least 30:1, preferably at least 35:1, preferably at least 40:1, preferably at least 45:1, preferably at least 50:1, preferably at least 55:1, preferably at least 60:1, to at most 250:1, preferably at most 225:1, preferably at most 200:1, preferably at most 175:1, preferably at most 150:1, more preferably at most 125:1, more preferably at most 120:1, more preferably at most 115:1, more preferably at most 110:1, even more preferably at most 105:1, still even more preferably at most 100:1, still even more preferably at most 95:1, still even more preferably at most 90:1.

[0124] Although the amount of the co-solvent (B2) can be adjusted, for example, to provide a desired level of solvation, preferred inkjet inks are those in which the weight ratio of the terpene phenol resin (A) to the co-solvent (B2) ((A):(B2)) is from at least 1:75, preferably at least 1:70, preferably at least 1:65, preferably at least 1:60, preferably at least 1:55, preferably at least 1:50, preferably at least 1:45, preferably at least 1:42.5, more preferably at least 1:40, more preferably at least 1:37.5, more preferably at least 1:35, even more preferably at least 1:32.5, still even more preferably at least 1:30, to at most 1:2, preferably at most 1:5, preferably at most 1:7, preferably at most 1:7.5, more preferably at most 1:8.

[0125] Other organic solvents in addition to ethanol (B1) and cosolvent (B2) can be used in any amount required for a particular application, with typical loading ranges up to 20 wt.%, preferably up to 15 wt.%, preferably up to 10 wt.%, preferably up to 5 wt.%, more preferably up to 4 wt.%, even more preferably up to 2 wt.% of the total weight of the inkjet ink, but higher loadings can sometimes also be used. In some embodiments, the inkjet ink is substantially free of methanol. In some embodiments, the inkjet ink is substantially free of polyols (also known as diols), such as ethylene glycol, propylene glycol, 1,3 - propanediol, 1,2 - butanediol, 1,3 - butanediol, 1,4 - butanediol, 2,3 - butanediol, 1,5 - pentanediol, neopentyl glycol, 1,6 - hexanediol, and 2 - methyl - 2,4 - pentanediol. In some embodiments, the inkjet ink is substantially free of other organic solvents.

[0126] In some embodiments, the inkjet ink is substantially free of solvents with a boiling point higher than 255 °C, preferably higher than 250 °C, preferably higher than 245 °C, preferably higher than 240 °C, preferably higher than 235 °C, preferably higher than 230 °C, preferably higher than 220 °C, preferably higher than 210 °C, more preferably higher than 200 °C, still more preferably higher than 195 °C.

[0127] In a preferred embodiment, the solvent system (B) consists of ethanol (B1) and cosolvent (B2).

[0128] In a preferred embodiment, the inkjet ink of the present disclosure is substantially non - aqueous, which means that no water is added to the inkjet ink except for an accidental amount of water that may be caused by environmental conditions. In such cases, the inkjet ink can have less than 1 wt.% water, preferably less than 0.5 wt.%, preferably less than 0.1 wt.%, more preferably less than 0.05 wt.%, even more preferably less than 0.01 wt.%, still more preferably 0 wt.%, based on the total weight of the inkjet ink.

[0129] Amine - modified silicone (C)

[0130] The amine - modified silicone can be a block copolymer having a pendant graft structure, which comprises (i) a silicone backbone (main chain) and (ii) more than one organic amine side chain attached to the silicone backbone, and optionally (iii) more than one fatty alkyl side chain attached to the silicone backbone or consisting thereof. Thus, as long as at least one organic amine side chain is attached to the silicone backbone, the material meets the definition of "amine - modified silicone", regardless of whether other side chain types (such as fatty alkyl side chains) are also attached to the silicone backbone. Preferably, there are no other side chains in the amine - modified silicone except for the organic amine side chains and the optional fatty alkyl side chains.

[0131] As described herein, a "side chain" is not a continuation of the silicone backbone, as in the case of linear block copolymers, such as an A-B-A structure, but is attached as a pendant graft to the silicone backbone (main chain), thereby forming a branch point on the silicone backbone, and the side chain extends from the silicone backbone by a covalent bond. Preferred organoamine-modified silicones are those that are non-hydrolyzable, i.e., silicones in which the side chain is attached to the silicone backbone by an Si-C bond.

[0132] <(i) Silicone backbone>The silicone backbone can be based on any organosilicon polymer or oligomer (polyorganosiloxane) having a linear or branched structure and variable molecular weight, which can be formed by the polymerization and / or polycondensation of appropriately functionalized silanes and has a polysiloxane backbone structure (silicon atoms are linked together by oxygen atoms -Si-O-Si-), with alkyl, aryl, and / or aralkyl groups directly bonded to the (tetravalent) silicon atoms. For example, the polyorganosiloxane backbone can be of linear structure, including but not limited to a polydimethylsiloxane (dimethylsiloxane) backbone (where each silicon atom in the backbone is directly bonded to two methyl groups), a poly(dimethylsiloxane-co-methylphenylsiloxane) backbone, a poly(dimethylsiloxane-co-diphenylsiloxane) backbone, and a poly(dimethylsiloxane-co-methylalkylsiloxane) backbone; or of branched structure, with particular mention of polydimethylsiloxane ethyl dimethylsiloxane.

[0133] <(ii) Organoamine side chain>The amine-modified silicone contains at least one organoamine side chain, which is based on an organoamine or an amine-containing polymer, such as a polyaziridine, for example those formed by the ring-opening polymerization of more than one alkyleneimine (where ethyleneimine (aziridine) and propyleneimine are most preferred), including copolymers, such as its block copolymers. Preferably, the organoamine side chain is an alkylamine, arylamine, aralkylamine, aliphatic amine, or polyaziridine extending from the silicone backbone.

[0134] The organoamine side chain can include primary, secondary, tertiary amines, or a combination of these. Such amines can be present in any suitable amount, for example 1 to 1000. In some embodiments, preferred organoamine side chains are selected from monoamines containing primary amines and diamines containing primary and secondary amines. Such monoamines can be alkylamines, arylamines, aralkylamines, or aliphatic amines. Such diamines can be alkylamines, arylamines, aralkylamines, or aliphatic amines.

[0135] <(iii) Fatty alkyl side chains> The amine-modified silicone may also be optionally modified with one or more fatty alkyl side chains, for example those containing at least 8 carbon atoms, preferably at least 10 carbon atoms, more preferably at least 12 carbon atoms and up to 22 carbon atoms, preferably up to 20 carbon atoms, more preferably up to 18 carbon atoms, even more preferably up to 16 carbon atoms, and even more preferably up to 14 carbon atoms. Exemplary fatty alkyl side chain groups include, but are not limited to, octyl, nonyl, decyl, undecyl, lauryl, tridecyl, myristyl, pentadecyl, hexadecyl, palmityl, heptadecyl, stearyl, oleyl, arachidyl and behenyl, with particular mention of lauryl, myristyl, hexadecyl and stearyl, preferably lauryl.

[0136] <(iv) Polyether Side Chains> The amine-modified silicone may also be optionally modified with one or more polyether side chains. The polyether side chains may be based on polyalkylene glycol oligomers or polymers, such as those formed by ring-opening polymerization of one or more alkylene oxides (of which ethylene oxide (EO), propylene oxide (PO) and / or butylene oxide (BO) are most preferred), including copolymers, such as block copolymers thereof. Preferably, the polyether side chains are polyethylene glycols or polyethylene glycol-polypropylene glycol copolymers extending from the silicone backbone, and more preferably, the polyether side chains are polyethylene glycol side chains formed only from ethylene oxide EO.

[0137] Various lengths of polyether side chains can be used, typically the number of moles of alkylene oxide units per side chain ranges from at least 2, preferably at least 3, more preferably at least 4, even more preferably at least 5, yet even more preferably at least 6, and up to 50, preferably up to 40, preferably up to 30, preferably up to 20, preferably up to 15, more preferably up to 12, even more preferably up to 10, yet even more preferably up to 9, particularly preferably 3 to 10, preferably 4 to 9 moles of alkylene oxide (EO) units per side chain.

[0138] Furthermore, any polyether side chains present may be uncapped (wherein the end of the polyether side chain opposite to the silicone backbone terminates in -H, forming a terminal hydroxyl function) or may be capped with an alkyl group having 1, 2, 3 or 4 carbon atoms (methyl, ethyl, propyl and butyl groups being mentioned in particular) (forming a terminal alkyl ether group).

[0139] In some embodiments, the amine-modified silicone is a block copolymer having a pendant graft structure, such as shown in formula (IA):

[0140]

[0141] Among them:

[0142] o is 0 or a positive integer, such as at least 1, preferably at least 2, more preferably at least 3, even more preferably at least 4, still more preferably at least 5, and at most 500, preferably at most 400, preferably at most 300, more preferably at most 200, even more preferably at most 100, still even more preferably at most 50;

[0143] p represents the number of structural units containing an organic amine side chain, and is a positive integer, such as at least 1, preferably at least 2, more preferably at least 3, even more preferably at least 4, even still more preferably at least 5, and at most 100, preferably at most 80, preferably at most 60, more preferably at most 40, even more preferably at most 20, still even more preferably at most 10; and

[0144] A is an amine-containing group (organic amine) as described above.

[0145] The amine-modified silicone having a pendant graft structure is formed from a linear polydimethylsiloxane backbone containing more than one organic amine side chain.

[0146] In some embodiments, the amine-modified silicone is a block copolymer having a pendant graft structure and optionally has more than one fatty alkyl side chain or polyether side chain as described above. In some embodiments, the amine-modified silicone is a block copolymer having a pendant graft structure, wherein the pendant graft structure has a branched polydimethylsiloxane backbone that contains more than one organic amine side chain and, optionally, as described above, more than one fatty alkyl side chain or polyether side chain.

[0147] In some embodiments, the inkjet ink is substantially free of non-amine-functionalized silicone. Examples of such silicones include unmodified silicones (e.g., silicones that do not have side chains containing non-siloxane functional groups) and modified silicones having only other non-amine functional groups, such as polyether-modified silicones (e.g., silicones having only polyether side chains), mercapto-modified silicones, vinyl-modified silicones, silanol-modified silicones, hydride-modified silicones, epoxy-modified silicones, (meth)acrylate-modified silicones, carboxylate-modified silicones, and haloalkyl-modified silicones. In some embodiments, the inkjet ink is free of non-amine-functionalized silicone. That is, the inkjet ink does not contain silicone that is not amine-functionalized. In these embodiments, the amine-modified silicone is the only silicone present in the inkjet ink. In some embodiments where the inkjet ink is free of non-amine-functionalized silicone, the amine-modified silicone can contain or comprise other functional groups as listed above. In some embodiments where the inkjet ink is free of non-amine-functionalized silicone, the amine-modified silicone does not contain or comprise other functional groups. That is, the inkjet ink does not contain silicone that is not amine-functionalized, and the amine-modified silicone present does not contain non-amine functional groups.

[0148] In some embodiments, the amine-modified silicone (C) is in mm at 25 °C2 The viscosity measured in / s is preferably at least 25, preferably at least 30, preferably at least 35, preferably at least 40, preferably at least 45, preferably at least 50, preferably at least 55, preferably at least 60 and at most 250, preferably at most 240, preferably at most 230, preferably at most 220, preferably at most 210, preferably at most 200, preferably at most 190, preferably at most 180, preferably at most 170, preferably at most 160, preferably at most 150, preferably at most 140, preferably at most 130, preferably at most 120, preferably at most 110 mm 2 / s.

[0149] In some embodiments, the amine-modified silicone preferably has an amine functional group equivalent weight (FGEW) of 350 to 11000 g / mol, preferably 1000 to 9000 g / mol, preferably 1500 to 8800 g / mol, preferably 1700 to 7600 g / mol, preferably 2000 to 7000 g / mol, preferably 3000 to 6500 g / mol, preferably 5000 to 6000 g / mol. The functional group equivalent weight refers to the weight of the amine-modified silicone containing one molecular weight of amine functional groups.

[0150] Suitable examples of amine-modified silicones that can be used in the disclosed inkjet inks include, but are not limited to, KF-865 (monoamino, functional group equivalent weight (FGEW) = 5000), KF-868 (monoamino, FGEW = 8800), KF-864 (monoamino, FGEW = 3800), KF-859 (diamino, FGEW = 6000), KF-393 (diamino, FGEW = 350), KF-860 (diamino, FGEW = 7600), KF-880 (diamino, FGEW = 1800), KF-8004 (diamino, FGEW = 1500), KF-8002 (diamino, FGEW = 1700), KF-8005 (diamino, FGEW = 11000), KF-867 (diamino, FGEW = 1700), KF-8021 (diamino, FGEW = 55000), KF-869 (diamino, FGEW = 3800), and KF-861 (diamino, FGEW = 2000), and all of the above products are available from Shin-Etsu Chemical Co. Particularly preferred amine-modified silicones are KF-859 and KF-865.

[0151] Based on the total weight of the inkjet ink, the content of the amine-modified silicone (C) in the inkjet ink can be at least 0.1 wt.%, preferably at least 0.125 wt.%, preferably at least 0.150 wt.%, preferably at least 0.175 wt.%, preferably at least 0.19 wt.%, preferably at least 0.20 wt.%, and at most 10 wt.%, preferably at most 7.5 wt.%, preferably at most 5 wt.%, preferably at most 2.5 wt.%, preferably at most 2.0 wt.%, preferably at most 1.5 wt.%, preferably at most 1.25 wt.%, preferably at most 1.2 wt.%.

[0152] Alkanolamine (D)

[0153] Alkanolamines are alkane compounds containing both a hydroxyl group (-OH) and an amino group (primary, secondary or tertiary).

[0154] In some embodiments, the alkanolamine (D) has a total of at least 2 carbon atoms, preferably at least 3 carbon atoms, preferably at least 4 carbon atoms, and at most 8 carbon atoms, preferably at most 7 carbon atoms, more preferably at most 6 carbon atoms, still more preferably at most 5 carbon atoms.

[0155] In a preferred embodiment, the alkanolamine (D) used in the inkjet ink herein has the following general formula II:

[0156]

[0157] Wherein, X, Y and Z are independently selected from:

[0158] - Hydrogen;

[0159] - C1-C5 alkyl, preferably C2-C3 alkyl; and

[0160] - Alkanol group, preferably C2-C5 alkanol group, more preferably C3-C4 alkanol group;

[0161] - Wherein, at least one of X, Y and Z is an alkanol group (alkyl substituent with at least one hydroxyl group).

[0162] In some embodiments, one of X, Y and Z is an alkanol group. In some embodiments, two of X, Y and Z are alkanol groups. In some embodiments, X, Y and Z are all alkanol groups.

[0163] Regarding the one or more alkanol groups, the alkyl chain thereof may contain branches. Alternatively, the alkyl chain of the alkanol group may be straight-chain (without alkyl branches). In a preferred embodiment, the alkanol group is based on a straight-chain alkyl chain. In addition, the carbon of the alkanol group bearing the hydroxyl group can be primary, secondary or tertiary carbon, preferably, the carbon bearing the hydroxyl group is primary or secondary carbon.

[0164] The alkanolamine (D) may contain a primary amino group (i.e., two of X, Y, and Z are hydrogen), a secondary amino group (i.e., one of X, Y, and Z is hydrogen), or a tertiary amino group (i.e., none of X, Y, and Z is hydrogen). When using an alkanolamine (D) containing a secondary amino group, the two non-hydrogen substituents may be the same or different alkanol groups, preferably the same alkanol group, such as in the case of diethanolamine. When using an alkanolamine (D) containing a tertiary amino group, the three non-hydrogen substituents may be the same or different alkanol groups, preferably the same alkanol group, such as in the case of triethanolamine.

[0165] Suitable examples of the alkanolamine (D) include, but are not limited to, ethanolamine, N-methylethanolamine, N,N-dimethylethanolamine, N-ethylethanolamine, N-propylethanolamine, N-isopropylethanolamine, N,N-diisopropylethanolamine, N-butylethanolamine, diethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, triethanolamine, propanolamine (3-amino-1-propanol), N-methylpropanolamine, N,N-dimethylpropanolamine, dipropanolamine, tripropanolamine, isopropanolamine, N,N-dimethylisopropanolamine, diisopropanolamine, triisopropanolamine, 2-amino-2-methyl-1-propanol, 2-amino-2-ethyl-1,3-propanediol, 4-amino-1-butanol, 2-amino-1-butanol, sec-butanolamine, and di-sec-butanolamine. In a preferred embodiment, the alkanolamine (D) is at least one selected from ethanolamine, propanolamine (3-amino-1-propanol), isopropanolamine, diethanolamine, and triethanolamine.

[0166] In some embodiments, relative to the total weight of the inkjet ink, the content of the alkanolamine (D) in the inkjet ink is at least 0.01 wt.%, more preferably 0.1 wt.%, further more preferably 0.2 wt.%, and preferably at most 5 wt.%, preferably at most 4 wt.%, preferably at most 3 wt.%, preferably at most 2.5 wt.%, preferably at most 2 wt.%, preferably at most 1.5 wt.%, preferably at most 1 wt.%. In some embodiments, the weight ratio of the terpene phenol resin (A) to the alkanolamine (D) ((A):(D)) is at least 0.25:1, preferably at least 0.5:1, preferably at least 0.6:1, preferably at least 1:1, and at most 2.5:1, preferably at most 2:1, preferably at most 1.75:1, preferably at most 1.5:1, preferably at most 1.25:1.

[0167] Colorant (E)

[0168] It is readily understood by those of ordinary skill in the art that more than one colorant (E) can optionally be included in the inkjet ink to provide a colored ink. In other words, the inkjet ink of the present invention may also contain a colorant (E), which can be used for various printing purposes, and the inkjet ink is not limited to any specific color. Any colorant (E) can be used in the inkjet ink to provide the desired color, including dyes, pigments, mixtures thereof, etc., provided that the colorant (E) can be dissolved or dispersed in the inkjet ink. Suitable colors include, for example, cyan, magenta, yellow, and key (black) ("CMYK"), white, orange, green, light cyan, light magenta, purple, etc., including spot colors and process colors.

[0169] The inkjet ink can be formulated with various dyes. The inkjet ink can be formulated with various inorganic pigments and / or organic pigments. In addition to providing color to the inkjet ink, such pigments are also capable of improving the lightfastness, weather resistance, etc. of the printed image.

[0170] Preferably, the inkjet ink of the present disclosure contains a colorant (E) that comprises a metal complex azo dye. In this context, the term "metal complex azo dye" refers to a dye that contains a compound formed by a metal center and a ligand, and the ligand contains an azo functional group (also known as a diazenyl functional group). Generally, a ligand containing an azo functional group is a molecule that can itself be regarded as an azo dye.

[0171] Such a ligand containing an azo functional group coordinates with the metal center, typically a transition metal or a main group metal or a metalloid, but not an alkali metal or an alkaline earth metal. Examples of suitable metals that can form the metal center include, but are not limited to, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, zirconium, niobium, molybdenum, ruthenium, rhodium, cadmium, aluminum, indium, tin, bismuth, and mixtures thereof. Such coordination can be carried out through any suitable functional group present on the ligand. Examples of such functional groups include, but are not limited to, oxygen-containing functional groups such as alcohols, alkoxides, carboxylic acids and carboxylates, esters, ketones, and ethers; nitrogen-containing functional groups such as amines, amides, azides, diazenyl (azo group), imines, porphyrins, imides, isonitriles, nitriles, and nitro functional groups; phosphorus-containing functional groups such as phosphines, phosphites, phosphates, phosphonites, phosphonates, phosphinates, and phosphinate functional groups; and sulfur-containing functional groups such as thiols, thiolates, disulfides, sulfones, sulfonic acids and sulfonates, sulfoxides, thioaldehydes, thioesters, thiosulfinates, thiocarboxylic acids and thiocarboxylates, sulfinic acids and sulfinates, thiocyanates, and isothiocyanates functional groups. The ligand coordinating with the metal center can be monodentate or bidentate, tridentate or tetradentate. Generally, as used herein, a ligand containing an azo group forms a coordination interaction with the metal center through one or two nitrogen atoms forming the azo group.

[0172] Generally, the remainder of the inner coordination sphere of the metal center can be further filled with any suitable ligand or combination of ligands known to those of ordinary skill in the art. Examples of suitable ligands include substances having oxygen-containing functional groups, such as alcohols, alkoxides, hydroxides, carboxylic acids and carboxylates, esters and ethers; substances having nitrogen-containing functional groups, such as amines (here understood to include ammonia), amides, azides, other diimines (also known as azo compounds), imines, porphyrins, imides, isonitriles, nitriles and nitro compounds; substances having phosphorus-containing functional groups, such as phosphines, phosphites, phosphates, phosphonites, phosphonates, hypophosphites and hypophosphates; substances having sulfur-containing functional groups, such as thiols, thiolates, disulfides, sulfones, sulfonic acids and sulfonates, sulfoxides, thioaldehydes, thioesters, thiosulfinates, thiocarboxylic acids and thiocarboxylates, sulfinic acids and sulfinates, thiocyanates and isothiocyanates; hydrocarbons containing more than one π-electron system, such as mesitylene, cyclopentadienyl anion and cyclooctadecene; halides; and water. Generally, the ligand can be monodentate, bidentate, tridentate, tetradentate or pentadentate, depending on the actual situation. However, hexadentate ligands, such as ethylenediaminetetraacetic acid (EDTA), are not suitable because these ligands do not leave open coordination sites for coordinating suitable ligands containing azo functional groups. Generally, the functional group can occupy any suitable position on the molecule acting as a ligand. For example, the alcohol or amine can be a primary alcohol or amine, secondary alcohol or amine, or appropriate tertiary alcohol or amine.

[0173] In a preferred embodiment, the metal complex azo dye is a metal complex comprising a metal center and (E)-1-((2-methoxy-5-nitrophenyl)diazenyl)naphthalen-2-ol or its deprotonated form, demethylated form, deprotonated and demethylated form, tautomer or stereoisomer. The structure of (E)-1-((2-methoxy-5-nitrophenyl)diazenyl)naphthalen-2-ol is shown in the following formula III:

[0174]

[0175] To form a suitable metal complex, and (E)-1-((2-methoxy-5-nitrophenyl)diazenyl)naphthalen-2-ol can exist in deprotonated form, demethylated form, or deprotonated and demethylated form, wherein in the deprotonated form, the hydroxyl group is deprotonated to form an alkoxide-type ligand (see the following formula (IV-A)), in the demethylated form, the methoxy group has been converted to an alkoxy-type ligand (see the following formula (IV-B)), and in the deprotonated and demethylated form, the hydroxyl group is deprotonated to form an alkoxide-type ligand, and the methoxy group has also been converted to an alkoxy-type ligand (see the following formula (IV-C)).

[0176]

[0177]

[0178] In a preferred embodiment, the metal center is a chromium ion. In some embodiments, the chromium ion is in the +3 oxidation state. In these embodiments, the metal complex can be positively charged, negatively charged, or uncharged. In embodiments where the metal complex is positively charged, the metal complex azo dye can further comprise any suitable anion to achieve charge balance. Examples of such suitable anions include, but are not limited to, carboxylates, halides, sulfates, phosphates, hydrogen phosphates, dihydrogen phosphates, nitrates, and mixtures thereof. In embodiments where the metal complex has a negative charge, the metal complex azo dye can further comprise any suitable cation for charge balance. Examples of such suitable cations include, but are not limited to, alkali metals, alkaline earth metals, ammonium compounds, and mixtures thereof.

[0179] Examples of suitable metal complex azo dyes include, but are not limited to, Solvent Black 27, Solvent Black 28, Solvent Black 29, Solvent Black 34, Solvent Blue 137, Solvent Brown 37, Solvent Brown 42, Solvent Brown 43, Solvent Brown 52, Solvent Orange 54, Solvent Red 8, Solvent Red 109, Solvent Red 119, Solvent Red 122, Solvent Yellow 19, Solvent Yellow 21, Solvent Yellow 25, Solvent Yellow 82, Solvent Yellow 88, Solvent Yellow 146, Solvent Violet 58, Solvent Violet 61, and VALIFAST BLACK 3870, VALIFAST RED 1355, and VALIFAST YELLOW 3150, respectively available from Orient Chemical Industries Co., Ltd., particularly Solvent Black 29 (also sold as VALIFAST Black 3870 (available from Orient Chemical Industries Co., Ltd.)) and Solvent Red 122 (also sold as VALIFAST Red 3312 (available from Orient Chemical Industries Co., Ltd.)).

[0180] The colorant can be included in the inkjet ink to provide any desired color, including dyes, pigments, mixtures thereof, etc., provided that the colorant can be dissolved or stably dispersed within the inkjet ink. Suitable colors include, for example, cyan, magenta, yellow, and key (black) (“CMYK”), white, orange, green, light cyan, light magenta, purple, etc., including spot colors and process colors.

[0181] In some embodiments, the content of the colorant (E) is preferably at least 0.1 wt.%, more preferably at least 0.5 wt.%, more preferably at least 1 wt.%, more preferably at least 2 wt.%, more preferably at least 3 wt.%, and preferably at most 20 wt.%, more preferably at most 15 wt.%, more preferably at most 10 wt.%, more preferably at most 8 wt.%, more preferably at most 7 wt.%, based on the total weight of the inkjet ink.

[0182] One or more additional colorants (E2) can optionally be included in the inkjet ink to provide colored inks that can be used for various printing purposes, and the inkjet ink is not limited to any particular color. Any additional colorant (E2) can be used in the inkjet ink to provide the desired color, including dyes, pigments, mixtures thereof, etc., provided that the additional colorant can be dissolved or dispersed in the inkjet ink. Suitable colors include, for example, cyan, magenta, yellow, and key (black) (“CMYK”), white, orange, green, light cyan, light magenta, purple, etc., including spot colors and process colors. Generally, the amount of the additional colorant (E2) can be at least 0.1 wt.%, preferably at least 0.5 wt.%, preferably at least 1 wt.%, preferably at least 2 wt.%, preferably at least 3 wt.%, and at most 20 wt.%, preferably at most 15 wt.%, preferably at most 10 wt.%, preferably at most 8 wt.%, preferably at most 7 wt.%, based on the total weight of the inkjet ink.

[0183] The inkjet ink can be formulated with various inorganic pigments and / or organic pigments. In addition to providing color to the inkjet ink, such pigments can also improve the lightfastness, weather resistance, etc. of the printed image.

[0184] Surfactant (F)

[0185] The inkjet ink of the present disclosure may optionally contain (F) a surfactant, for example, to provide benefits such as anti-blocking, ink receptivity, leveling, anti-foaming, increased surface slipperiness, and / or substrate wettability without sacrificing the opening and adhesion properties of the inkjet ink. When used, the amount of the surfactant (F) may range from at least 0.01 wt.%, preferably at least 0.015 wt.%, preferably at least 0.02 wt.%, preferably at least 0.04 wt.%, more preferably at least 0.06 wt.%, even more preferably at least 0.08 wt.%, even more preferably at least 0.1 wt.%, even more preferably at least 0.15 wt.%, even more preferably at least 0.2 wt.%, even more preferably at least 0.25 wt.%, even more preferably at least 0.3 wt.%, even more preferably at least 0.35 wt.%, even more preferably at least 0.4 wt.%, still even more preferably at least 0.45 wt.%, even more preferably at least 0.5 wt.%, and up to 5 wt.%, preferably up to 4 wt.%, preferably up to 3 wt.%, preferably up to 2 wt.%, preferably up to 1 wt.%, preferably up to 0.95 wt.%, preferably up to 0.9 wt.%, even more preferably up to 0.85 wt.%, even more preferably up to 0.8 wt.%, based on the total weight of the inkjet ink.

[0186] Examples of the surfactant (F) that can be used alone or in combination herein include, but are not limited to,

[0187] - Polysiloxanes, which include organically modified silicones (e.g., alkyl, aryl, and / or aralkyl modified silicones), such as SILTECH C-32, available from SILTECH Corporation, COATOSIL 1211C and 3573, each available from Momentive, KF-410 (aralkyl modified polydimethylsiloxane), available from Shin-Etsu Chemical Co., and BYK-322 and BYK-323 (aralkyl modified poly(dimethylsiloxane-co-methylalkylsiloxane)), both available from BYK Additions&Instruments;

[0188] - Silicone acrylate copolymers, such as KP-541, KP-543, KP-545, KP-550, and KP-575 (acrylic polymers grafted with polydimethylsiloxane side chains, available from Shin-Etsu Chemical Co., Ltd.) and BYK-3550 (available from BYK Japan K.K.);

[0189] - Polyether-modified silicones, including block copolymers having pendant graft structures formed from linear or branched polydimethylsiloxane backbones, said backbones comprising more than one polyether side chain and optionally more than one fatty alkyl side chain as described above;

[0190] - Fluoropolymers such as FC-4430 and FC-4432 available from 3M Company;

[0191] - Polyether-modified silicones, including block copolymers having pendant graft structures formed from linear or branched polydimethylsiloxane backbones, said backbones comprising more than one polyether side chain and optionally more than one fatty alkyl side chain, such as KF-6013 (PEG-9 dimethylpolysiloxane, uncapped, HLB = 10.0), KF-6015 (PEG-3 dimethylpolysiloxane, uncapped, HLB = 4.5), KF-6017 (PEG-10 dimethylpolysiloxane, uncapped, HLB = 4.5) and KF-6038 (lauryl PEG-9-polydimethylsiloxyethyl dimethylpolysiloxane, uncapped, HLB = 3.0), all available from Shin-Etsu Chemical Co., and BYK-307 (polyether-modified polydimethylsiloxane) available from BYK Additives & Instruments as described above;

[0192] - Photocrosslinkable silicone acrylates or silicone polyether acrylates, such as TEGO RAD 2100, TEGO RAD2200, TEGO Rad2250, TEGO RAD 2300 (silicone polyether acrylate), each available from Evonik Industries, and BYK-UV 3500 and 3530 available from BYK;

[0193] - Polyacrylates, including polyacrylate copolymers and crosslinked polymers, such as BYK-381 and BYK-361N (polyacrylate copolymers), each available from BYK, PEMULEN EZ-4U (acrylate / C10-C30 alkyl acrylate crosslinked polymer) and PEMULEN TR-2 (acrylic acid / C10-C30 alkyl acrylate crosslinked polymer), each available from Lubrizol;

[0194] - Alkynediols and alkynediol-based gemini surfactants such as SURFYNOL SEF and DYNOL surfactants available from Evonik Industries;

[0195] - Polysiloxane-based gemini surfactants such as TEGO TWIN 4100 available from Evonik Industries;

[0196] - Nonionic polyethers, such as, for example, as a substrate wetting surfactant, such as TEGO WET 510 (hydrophilic polyether substrate wetting activator) available from Evonik Industries;

[0197] - Amides or monoalkanolamides of fatty acids, including alkoxylated monoalkanolamines of fatty acids, such as coconut fatty acid monoethanolamide and coconut fatty acid monoethanolamide reacted with 2 - 20 moles of ethylene oxide;

[0198] - Ethers, such as alkoxylated C1 - C 22 Alcohols, including alkoxylated fatty alcohols, such as BIO - SOFT N - 600 (C12 - C13 alcohol ethoxylate), MAKON DA - 4 (ethoxylated isodecyl alcohol), MERPOL SE (alcohol ethoxylate), and POLYSTEP TD - 6 (ethoxylated tridecyl alcohol), each available from Stepan, ethylene oxide / propylene oxide copolymers, alkoxylated alkylphenols, and alkyl polyglycosides (APGs), such as those prepared by the reaction of fatty alcohols and glucose;

[0199] - Fatty esters, such as ethoxylated and / or propoxylated fatty acids (such as castor oil containing 2 to 40 moles of ethylene oxide), alkoxylated glycerol esters (such as PEG - 24 monostearate), ethylene glycol esters and derivatives, monoglycerides, polyglycerides, polyol esters, and sorbitan / sorbitol esters, such as sorbitan monolaurate (such as EMASOL L - 10V available from Kao), and polysorbates, including mono-, di-, or tri - fatty acid - esterified polysorbates such as TOXIMUL SEE - 340 (sorbitan trioleate ethoxylate (20)) available from Stepan;

[0200] - Glycosides of fatty alcohols, such as PLANTASENS NATURAL EMULSIFIER HE20 (cetearyl glucoside, sorbitan oleate) available from Clariant;

[0201] - Sulfates, sulfonates, phosphates, and phosphonates of fatty alcohols, such as alkyl sulfates, alkyl ester sulfates, alkyl ether sulfates, alkyl alkoxylate sulfates, sulfated alkanolamides, glycerol ester sulfates, alkyl sulfonates, fatty alkylbenzene sulfonates, lower alkylbenzene sulfonates, α - olefin sulfonates, lignin sulfonates, alkyl aryl ether phosphates, alkyl ether phosphates, and phosphates, or polyoxyalkylene ethers of fatty alcohols; and

[0202] - Amphoteric surfactants, including but not limited to: fatty alkyl betaines, such as lauryl betaine (e.g., AMPHITOL 24B available from Kao); fatty alkyl amidobetaines, such as fatty amide propyl dimethylamino betaine; fatty alkyl sulfobetaines, such as fatty dimethyl hydroxy sulfobetaine; fatty alkyl amidosulfobetaines, such as fatty amide propyl dimethylamino hydroxy sulfobetaine; amine oxides, such as N-cocoyl amide propyl dimethylamine oxide, N-cocoyl amide propyl dimethylamine oxide, dimethyl fatty alkyl amine oxide (such as dimethyl coconut amine oxide, lauryl dimethylamine oxide (e.g., AMPHITOL 20N available from Kao); and imidazolium amphoteric surfactants;

[0203] (e.g., ELEC AC available from Kao).

[0204] In some embodiments, the inkjet inks of the present disclosure are substantially free of silicone-containing surfactants. In some embodiments, the inkjet inks of the present disclosure are substantially free of polyether-containing surfactants. In some embodiments, the inkjet inks of the present disclosure are substantially free of surfactants, such as those listed above.

[0205] (G) Additives

[0206] In addition to the ingredients already mentioned, the inkjet inks can optionally be formulated with various additives (G) to improve various ink properties and performance. For example, the inkjet inks can optionally contain one or more anti-caking agents, stabilizers, humectants, security tagging agents, or other inkjet ink additives known to those of ordinary skill in the art at appropriate levels in the art.

[0207] The inkjet inks can optionally contain one or more opacifying agents, examples of which can include but are not limited to titanium dioxide, zirconium silicate, zirconium oxide, tin oxide, cerium oxide, zinc oxide, aluminum oxide, silicon dioxide, kaolin, calcium carbonate, magnesium carbonate, calcium magnesium carbonate, barium carbonate, albite, orthoclase, nepheline, calcium silicate, mullite, wollastonite, and talc.

[0208] Preparation Method

[0209] Embodiments of the inkjet inks described herein can be prepared by any suitable technique known to those of ordinary skill in the art, such as by combining (A) terpene phenolic resin, a solvent system (B) comprising (B1) ethanol and (B2) co-solvent, (C) amine-modified silicone, and any desired optional ingredients (such as terpene resin, (E) colorant, (D) alkanolamine, (F) surfactant, and / or (G) additive, in any order, followed by stirring, agitating, and / or homogenizing for an appropriate amount of time at a temperature of 20 to 100 °C to form a homogeneous solution.

[0210] Then, the obtained inkjet ink can be placed in a printing cartridge, such as a FUNAI TIJ cartridge manufactured by FUNAI Co., or other print heads suitable for keto-based inks.

[0211] Performance

[0212] The inkjet inks disclosed herein have an extended open cap time, which is measured, for example, by printing a narrow line picture (e.g., a bar code) (1 mm * 1 cm, narrow line, monochromatic bitmap), exposing the inkjet ink to air (open cap cartridge) for a specific time (e.g., 30 seconds, 1 minute, 10 minutes, 60 minutes, etc.), reprinting the same narrow line image, and comparing the reprinted image after opening the cap with the original image to determine whether there is a loss of lines / loss of line clarity in the narrow line image. If there is no loss of lines / loss of line clarity within the tested time interval, the inkjet ink is given a "good" open cap rating for that time interval. If there are 1 - 2 lines lost / loss of clarity within the tested time interval, but it is not sufficient to significantly affect the clarity or readability of the narrow line image, the inkjet ink is given an "acceptable" open cap rating for that time interval. If more than 2 lines are lost / loss of clarity within the tested time interval, the inkjet ink is classified as "bad" for that time interval. Suitable inkjet inks are those that achieve an "acceptable" or "good" open cap classification when opened (i.e., exposed to air) for more than 30 seconds, preferably more than 1 minute, more preferably more than 10 minutes, even more preferably more than 30 minutes, and still more preferably more than 60 minutes.

[0213] The inkjet inks disclosed herein are further characterized by excellent adhesion to various substrates. Adhesion is typically tested using a "peel tape test", in which a tape (usually 3M tape) is applied to the dried printed ink and then removed. Good ink adhesion is characterized by little ink being removed from the substrate, i.e., little detectable ink on the tape, and / or no detectable change in the printed ink. An "acceptable" rating is characterized by a significant amount of ink being removed from the substrate, i.e., visible ink on the tape, and / or a noticeable change in the printed ink, such as gridling or fading. A "poor" rating is characterized by a large amount of ink being removed from the substrate, i.e., a large amount of visible ink on the tape (a replica of the print may be visible on the tape), and / or a significant decrease in the quality of the print, such as gridling or fading).

[0214] The characteristics of the inkjet ink disclosed in this article may also be long-term running stability (also known as ink life or printing life). To test the running stability of the inkjet ink, a narrow-line image (such as a barcode) (1mm * 1cm, narrow line, monochrome bitmap) can be printed continuously for several pages without interruption (for example, printed on 3000 pages in a continuous printing operation), and the printing quality can be evaluated by visually inspecting certain pages (such as page 1000, page 2000, and page 3000) throughout the printing operation for nozzle failure. If there is no loss of lines / loss of line clarity in the inspected pages, the running stability rating of the inkjet ink for that page is "G" (good). If there are 1-2 lines lost / loss of clarity in the inspected pages, but it is not sufficient to significantly affect the clarity or readability of the narrow-line image, the running stability rating of the inkjet ink for that page is "A" (acceptable). If more than 2 lines are lost / loss of clarity in the inspected pages, the running stability rating of the inkjet ink is "NG" (not good). When printing at least 100 pages, preferably at least 500 pages, preferably at least 1000 pages, preferably at least 1500 pages, preferably at least 2000 pages, preferably at least 2500 pages, preferably at least 3000 pages, preferably at least 3500 pages, preferably at least 4000 pages, preferably at least 4500 pages, preferably at least 5000 pages, and maintaining a "G" or "A" rating, preferably a "G" rating, the inkjet ink is considered ideal in terms of running stability (able to maintain dispersion / suspension without precipitation / sedimentation and improper jetting).

[0215] Printed matter

[0216] Inkjet inks can be printed on a variety of substrates, including three-dimensional parts and flat sheets or webs supplied in roll form, for the manufacture of a variety of printed articles. While flat substrates are suitable substrates for forming printed articles, a particular advantage of the present disclosure is that the disclosed inkjet inks are capable of forming printed images on complex three-dimensional substrates, such as substrates that are radial, curved, serrated, corrugated, grooved, flanged, and / or have a structured surface (such as a particulate surface), all of which substrates are notoriously difficult substrates because the ink must travel long distances to reach all parts of the complex surface. Printed articles may be suitable for the graphic arts, textiles, packaging (such as food packaging, pharmaceutical packaging, etc.), lottery tickets, direct mail, business forms, and the publishing industry, examples of which include signs or labels, lottery tickets, publications, packaging (such as food packaging, pharmaceutical packaging, blister packaging, various other flexible packaging, etc.), folding cartons, rigid containers (such as plastic cups or buckets, glass containers, metal cans, PET bottles, jars, and tubes, etc. bottles), envelopes, corrugated cardboard, point-of-sale displays, etc. Particularly preferred printed articles are printed articles having a dry form of the inkjet ink disposed on the complex three-dimensional portions of the printed article, for example, where the printed image is located on the ribbed or corrugated portion of a plastic container, or on the concave domed bottom of a metal can.

[0217] Inkjet inks can be printed on porous (or permeable) substrates, examples of which include, but are not limited to, uncoated paper, wood, membranes, corrugations (corrugated cardboard / fiberboard), and fabrics (including, but not limited to, woven fabrics, non-woven fabrics, and foil laminated fabrics).

[0218] Inkjet inks can also be printed on non-porous (or impermeable substrates), such as various plastics, glass, metals (such as steel, aluminum, etc.), and / or non-permeable papers (such as coated papers like varnish-coated paper), including, but not limited to, molded plastic or metal parts and flat sheets or rolls of plastic or metal films. Examples include substrates containing polyesters such as polyethylene terephthalate (PET), biaxially oriented polystyrene (OPS), polyolefins such as polyethylene (PE), polypropylene (PP), oriented polypropylene (OPP), and biaxially oriented polypropylene (BOPP), polylactic acid (PLA), nylon and oriented nylon, polyvinyl chloride (PVC), triacetyl cellulose (TAC), polycarbonate, acrylonitrile-butadiene-styrene (ABS), polyacetal, polyvinyl alcohol (PVA), coated papers such as varnish-coated paper, and metals such as steel and aluminum, etc.

[0219] Method for forming a printed image

[0220] For inkjet printing, when precise dot patterns are ejected from an ink droplet generating device called a print head onto a print medium, a desired printed image is formed. The print head has a set of precisely formed nozzles located on a nozzle plate and attached to an inkjet print head substrate. The inkjet print head substrate contains a set of firing chambers that receive inkjet ink by being in fluid communication with more than one reservoir. Each firing chamber has a resistor element called a firing resistor arranged opposite the nozzle such that the inkjet ink is collected between the firing resistor and the nozzle. Each resistor element is typically a pad of resistive material and is sized, for example, to be about 35 μm × 35 μm. The print head is held and protected by an outer package called a print cartridge or inkjet pen. When a particular resistor element is energized, droplets of inkjet ink are ejected through the nozzle towards the print medium. The ejection of the ink droplets is typically under the control of a microprocessor, whose signals are transmitted through electrical traces to the resistor element, thereby forming alphanumeric and other image patterns on the print medium. Since the nozzles are very small, typically having a diameter of 10 μm to 40 μm, it is desirable to have an ink that minimizes clogging. In particular, since thermal inkjet (TIJ) is an open-atmosphere print head design (the nozzle holes are open to the atmosphere and there is no valve seal at the holes to allow ink pressurization), TIJ printing has historically performed poorly during intermittent printing processes, where the open lid time (print idle time) causes premature drying of the ink inside and around the nozzles.

[0221] The present disclosure provides a method of forming a printed image on a substrate by applying the inkjet ink of the present invention onto the substrate with a thermal inkjet print head and drying the inkjet ink. Using the inkjet ink described herein overcomes the problem of short open lid times (too fast solvent loss rate) typically associated with thermal inkjet processes.

[0222] In some embodiments, the substrate is substantially free of amine-modified silicone. Such amine-modified silicone can be present on the surface of the substrate. In certain printing methods or applications, amine-modified silicone is applied to the substrate before the ink is applied. Preferably, the methods described herein do not include applying amine-modified silicone before applying the inkjet ink. Preferably, in the methods described herein, the inkjet ink is applied to a surface that is free of amine-modified silicone.

[0223] Any drop-on-demand inkjet printhead known to those of ordinary skill in the inkjet printing art can be used as the printing unit in the method of the present invention, including continuous printheads, thermal printheads, electrostatic printheads, and acoustic printheads. A thermal printhead (with a thermal transducer) is preferably used. Typical parameters can be adjusted according to the specifications of the printhead, such as print resolution, print speed, printhead pulse heating temperature, drive voltage, and pulse length. The droplet size of the printhead typically applicable to the method herein is in the range of 2 - 80 pL, the droplet frequency is in the range of 10 - 100 kHz, and high-quality printing can be obtained by, for example, setting the drive voltage to 8.0 - 9.5 volts, setting the print speed to at most 300 feet per minute, setting the pulse heating temperature to 25 - 45 °C, and setting the pulse length to 0.7 - 2.5 microseconds, although values above or below the stated values can also be used and still obtain satisfactory printing. An example of a non-limiting printhead applicable to the disclosed method is the HP TIJ cartridge manufactured by HP.

[0224] After application, the inkjet ink is dried. In some embodiments, external heat can be applied to dry the applied inkjet ink, such as by using a heater. However, it is preferred not to apply external heat to facilitate drying or increase the drying speed. Thus, in preferred embodiments, drying is achieved by allowing the applied inkjet ink to dry in ambient conditions (in air, at about 23 °C) for less than 30 seconds, preferably less than 25 seconds, more preferably less than 20 seconds, even more preferably less than 15 seconds, and even more preferably less than 10 seconds, without using an external heat source such as a heater. Additionally, the method of the present disclosure does not require energy curing (e.g., UV or electron beam curing). Once the applied ink is considered dry, a further coating of the inkjet ink can be applied, or any processing steps known to those of ordinary skill in the art can be performed as needed.

[0225] It should also be recognized that substrate surface treatment, such as corona treatment, atmospheric plasma treatment, and flame treatment, can optionally be employed in the method herein prior to applying the inkjet ink to improve the characteristics of the printed matter, such as ink adhesion. The parameters of such substrate surface treatment can vary widely depending on the substrate material to be printed, the specific inkjet ink used, the printing method applied, and the desired characteristics and applications of the printed matter.

[0226] The following examples are intended to further illustrate the inkjet ink and are not intended to limit the scope of the claims.

[0227] Examples

[0228] Material

[0229] DERTOPHENE T105 is a terpene phenolic resin (OHV = 20 - 60 mgKOH / g; SP = 105 °C; Mw = about 700 g / mol), which can be obtained from DRT / Pinova. Shin Etsu KF865 is a side-chain type monoamino-modified silicone (viscosity at 25 °C = 110 mm 2 / s; specific gravity at 25 °C = 0.97; refractive index at 25 °C = 1.405; functional group equivalent = 5000 g / mol), Shin Etsu KF 859 is a side-chain type diamino-modified silicone (viscosity at 25 °C = 60 mm 2 / s, specific gravity at 25 °C = 0.96; refractive index at 25 °C = 1.403; functional group equivalent = 6000 g / mol), and Shin Etsu KF6015 is a side-chain type polyether-modified silicone (viscosity at 25 °C = 130 mm 2 / s); specific gravity at 25 °C = 1.00; refractive index at 25 °C = 1.419; hydrophilic-lipophilic balance value (HLB) = 4.5 - 5), each of which can be obtained from ShinEtsu Silicone.

[0230] Valifast Black 3870 (also known as Solvent Black 29 or SB29) is a metal complex azo dye, which can be obtained from Orient Chemical Industries. Valifast Red 3312 (also known as Solvent Red 122) is a metal complex azo dye, which can be obtained from Orient Chemical Industries.

[0231] Method for evaluating inkjet ink

[0232] Print sample preparation

[0233] The inkjet ink examples were evaluated using an HP TIJ cartridge manufactured by HP. The ink was evaluated using HP-related thermal printing technology (software and hardware manufactured by Norwix, transport table manufactured by Kirk Rudy).

[0234] Open lid time evaluation

[0235] To evaluate the open lid time, the following printing conditions were used:

[0236] - Printing substrate; plain (uncoated) paper

[0237] - Printing resolution; 300 dpi * 300 dpi (vertical * horizontal)

[0238] - Voltage 8.6 V

[0239] - Pulse width 1.8 μsec

[0240] - Pulse heating off

[0241] - Print an image; 100% duty cycle (1 mm * 1 cm, monochrome bitmap, narrow line image) (see, for example, Figure 2 )

[0242] Print a narrow line image to confirm that there are no missing or unclear lines in the printed image (indicating nozzle clogging or failure). After confirmation, open the printhead cover for a specific time (60 minutes), then reprint using the same narrow line image. Check the reprinted narrow line image (after a specific time interval) to determine if there has been line loss / loss of line clarity. If there has been no line loss / loss of line clarity, the inkjet ink is given a "good" open cover rating for that time interval. If 1 - 2 lines are lost / lose clarity during the tested time interval, but it is not sufficient to significantly affect the clarity or readability of the narrow line image during the tested time interval, the inkjet ink is given an "acceptable" open cover rating for that time interval. If more than 2 lines are lost / lose clarity during the tested time interval, the inkjet ink is classified as "bad" for that time interval. A suitable / ideal inkjet ink is one that achieves an "acceptable" or "good" open cover classification when the cover is opened (i.e., exposed to air) at each tested time interval.

[0243] Adhesion evaluation

[0244] The ink is printed on an LDPE film. One minute after printing, a light packaging tape 600 is gently pressed onto the ink and then immediately peeled off. The performance of the ink is ranked according to the description in Table 1 below. Light packaging tape 600 is gently pressed onto the ink and then immediately peeled off. The performance of the ink is ranked according to the description in Table 1 below.

[0245] Table 1. Ink evaluation indicators

[0246]

[0247] Examples of inkjet ink

[0248] Tables 2A - 2B give examples of inkjet inks. The amount of each component is expressed as a weight percentage relative to the total weight (50 parts) of the inkjet ink.

[0249] * Indicates that this example is a comparative example.

[0250] Preparation method

[0251] To prepare the example inks, first the resin, amine-modified silicone, and any surfactant are mixed with the said combination of ethanol and co-solvent, and then mixed for at least 30 minutes by a mechanical stirrer. Then the dye is added to the mixture and mixed for at least 30 minutes to obtain an inkjet ink. Then the inkjet ink examples are evaluated using HP TIJ cartridges manufactured by HP.

[0252] Table 2A. Inkjet Ink Examples 1 - 8

[0253]

[0254] Table 2B. Inkjet Ink Examples 9 - 16

[0255]

[0256] Inkjet Ink Performance

[0257] As can be seen from Table 3, the combination of amine-modified silicone, ethanol, co-solvent, and terpene-phenol resin provides significant effects in terms of open time and adhesion (Examples 3, 4, 5, 7, 8, 9, 10, and 13). In contrast, the inkjet inks without amine-modified silicone (Example 1) and without co-solvent (Example 12) perform poorly in each test, and the results in terms of open time and adhesion are classified as "bad". The addition of polyether-modified silicone (Example 6) shows a suitable open time, but the adhesion is unacceptable. Excluding ethanol (Example 11) or terpene-phenol resin (Example 15) shows good adhesion, but unacceptable open time behavior.

[0258] In terms of the amount of co-solvent, a loading range of 4.5 to 15 parts (9 to 30 wt.%) provides acceptable or good open behavior and acceptable or good adhesion on all substrates (see Examples 2, 3, 4, 5, 7, 8, 9, 10, 11, 13, 14, and 16).

[0259] Table 3A. Evaluation of Inkjet Ink Examples 1 - 8

[0260]

[0261] Table 3B. Evaluation of Inkjet Ink Examples 9 - 16

[0262]

[0263] G: Good; A: Acceptable; X: Bad.

[0264] If numerical limitations or ranges are specified herein, the endpoints are included. In addition, all values and sub-ranges within the numerical limitations or ranges are explicitly included as if they were explicitly written out.

[0265] As used herein, words such as "a" and "an" have the meaning of "more than one".

[0266] The present disclosure also contemplates other embodiments of the embodiments or elements described herein that "comprise", "consist of", and "consist essentially of", whether or not explicitly set forth.

[0267] Obviously, many modifications and variations of the present invention are possible in light of the above teachings. Accordingly, it is to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.

[0268] All of the above patents and other references are hereby incorporated by reference in their entirety as if set forth in detail.

Claims

1. An inkjet ink, wherein, it comprises: (A) a terpene phenol resin; (B) a solvent system comprising (B1) ethanol and (B2) a cosolvent; and (C) an amine-modified silicone, wherein the amine-modified silicone (C) comprises: a silicone backbone as the main chain, and one or more organic amine side chains attached to the silicone backbone.

2. The inkjet ink according to claim 1, wherein, the terpene phenol resin (A) is a copolymer comprising a monoterpene segment and a phenol segment containing a phenolic compound, wherein the phenol segment is connected to the monoterpene segment at at least one position selected from the ortho position relative to the phenolic hydroxyl group and the para position relative to the phenolic hydroxyl group.

3. The inkjet ink according to claim 2, wherein, the monoterpene segment is at least one bicyclic monoterpene selected from 3-carene, α-pinene, β-pinene, and camphene, and the phenolic compound is phenol.

4. The inkjet ink according to claim 1, wherein, the hydroxyl value of the terpene phenol resin (A) is 10 to 75 mgKOH / g.

5. The inkjet ink according to claim 1, wherein, based on the total weight of the inkjet ink, the content of the terpene phenol resin (A) is 0.1 to 10 wt.%.

6. The inkjet ink according to claim 1, wherein, the (B2) cosolvent is at least one selected from n-propanol, methyl ethyl ketone, ethyl acetate, propylene glycol monomethyl ether, and 1,3-dioxolane.

7. The inkjet ink according to claim 1, wherein, (B1) the weight ratio of ethanol to (B2) the cosolvent (B1):(B2) is 1:1 to 25:

1.

8. The inkjet ink according to claim 1, wherein, the organic amine side chain is at least one selected from a monoamine containing a primary amine and a diamine containing a primary amine and a secondary amine.

9. The inkjet ink according to claim 1, wherein, The viscosity of the amine-modified silicone (C) at 25 °C is 25 to 250 mm 2 / s.

10. The inkjet ink according to claim 1, wherein, the amine functional group equivalent of the amine-modified silicone is 350 to 11000 g / mol.

11. The inkjet ink according to claim 1, wherein, the content of the amine-modified silicone is 0.1 to 10 wt.%.

12. The inkjet ink according to claim 1, wherein, it is substantially free of polyether-functionalized siloxane.

13. The inkjet ink according to claim 1, wherein, it further comprises (D) an alkanolamine.

14. The inkjet ink according to claim 13, wherein, based on the total weight of the inkjet ink, the content of the alkanolamine (D) is 0.01 to 5 wt.%.

15. The inkjet ink according to claim 13, wherein, the alkanolamine (D) is at least one selected from ethanolamine, propanolamine, isopropanolamine, diethanolamine, and triethanolamine.

16. The inkjet ink according to claim 1, wherein, it further comprises (E) a colorant.

17. The inkjet ink according to claim 16, wherein, the colorant (E) is a metal complex azo dye.

18. A printed article, wherein, it comprises: a substrate and a dried form of the inkjet ink according to claim 1 provided on the substrate.

19. A method of forming a printed image on a substrate, wherein, the method comprises: applying the inkjet ink according to claim 1 to the substrate using a thermal inkjet printhead; and drying the inkjet ink, wherein the substrate is substantially free of amine-modified silicone.

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