Solvent-based inkjet inks

Abstract

An inkjet ink comprising: (A1) a terpene resin; and (B) a solvent system comprising (B1) a ketone solvent having a boiling point below 120° C. and (B2) a dioxolane, the inkjet ink being characterized by an extended decapping time and a long jetting distance. Also provided are a printed article comprising the inkjet ink in a dried form, and a method for forming a printed image using a thermal inkjet printhead.

Description

Technical Field

[0001] The present invention relates to solvent-based inkjet inks, in particular to inkjet inks formulated from (A1) a terpene resin and (B) a solvent system comprising (B1) a ketone solvent having a boiling point below 120° C. and (B2) a dioxolane. Background Art

[0002] The "background" description provided herein is intended to generally present the context of the present disclosure. To the extent described in this background section, the work of the inventors, as well as aspects of the description that may not qualify as prior art at the time of filing, are neither explicitly nor implicitly admitted to be prior art to the present invention.

[0003] Thermal inkjet (TIJ) printing is an ideal printing, coding and marking technology because it provides high print resolution at a lower cost than competing technologies in this field, such as continuous inkjet (CIJ) methods. In the thermal inkjet printing process, the print cartridge contains an array of tiny chambers, each of which contains a heater that produces ink droplets through the thermal evaporation of the ink solvent. During the jetting process, the resistor is rapidly heated to produce a vapor bubble (hence the name "bubble jet"), which is then ejected from the nozzle. The process is very efficient and repeatable, and modern TIJ print heads for industrial graphics applications are capable of producing uniform droplets with a volume of 4pL or less at frequencies of 36kHz or higher.

[0004] However, industrial marking and coding often require printing basic information, such as personal information, labels, codes, dates (e.g., expiration dates), and traceability information (e.g., production batches), on substrates with complex surfaces, such as radial, curved, jagged, corrugated, grooved, and / or lipped substrates. These complex substrates can introduce large gaps between the print head and the substrate surface, which poses a significant challenge to TIJ technology, which traditionally can only operate at a throw distance of approximately 1 to 2 mm. When the ink must travel a distance exceeding its throw distance performance capability before reaching the substrate surface, the resulting printed image will have poor image quality (e.g., lack of clarity, unclear outlines) due to inaccuracies and defects in droplet placement. Poor image quality is unacceptable for many applications, but is particularly true for marking and coding basic information. Therefore, even with its other advantages, TIJ technology has only gained moderate acceptance in marking / coding applications because it cannot compete with the throw distances offered by CIJ technology, which are typically in the range of 5 to 12 mm.

[0005] Furthermore, thermal inkjet printing can suffer from poor reliability after periods of inactivity. For example, some inkjet inks have a short decap time, where solvent loss caused by prolonged exposure to air within an uncapped printhead can lead to clogging / clogging of the printhead nozzles, resulting in unreliable inkjet and diminished image quality over time.

[0006] Solvent-based inkjet inks prepared using a specific combination of a binder resin and a volatile organic solvent selected from C1-C4 alcohols, C3-C6 ketones, C3-C6 esters, and C4-C8 ethers have previously been reported to have acceptable decap times and high adhesion to non-porous plastics (see US2018 / 0251650, which is hereby incorporated by reference in its entirety). However, this ink system only prints at a jetting distance of 1 mm, and there are no reports of improvements in jetting distance. Summary of the Invention

[0007] In view of the foregoing, there is a need for inkjet inks that have an extended de-seal time and are capable of printing at long jetting distances (eg, 8-15 mm).

[0008] It was therefore an object of the present invention to provide novel inkjet inks which meet these criteria.

[0009] It is another object of the present disclosure to provide novel printed articles comprising inkjet inks in dry form.

[0010] Another object of the present disclosure is to provide a novel method for forming a printed image on a substrate by applying inkjet ink to the substrate and drying it.

[0011] As will be seen in the detailed description below, these and other objects have been achieved by the inventors' discovery that a combination of a terpene resin, a ketone solvent having a boiling point below 120°C, and a dioxolane provides an inkjet ink characterized by extended decap time and long jetting distance (e.g., 8-15 mm).

[0012] Therefore, the present invention provides:

[0013] (1) An inkjet ink comprising:

[0014] (A1) terpene resin; and

[0015] (B) A solvent system comprising (B1) a ketone solvent having a boiling point lower than 120° C. and (B2) dioxolane.

[0016] (2) The inkjet ink according to (1), wherein the terpene resin (A1) is present in an amount of 0.1 to 10 wt. % based on the total weight of the inkjet ink.

[0017] (3) The inkjet ink according to (1) or (2), wherein the terpene resin (A1) is a homopolymer made of α-pinene.

[0018] (4) The inkjet ink according to any one of (1) to (3), wherein the ketone solvent (B1) is present in an amount of 1 to 90 wt. % based on the total weight of the inkjet ink.

[0019] (5) The inkjet ink according to any one of (1) to (4), wherein the ketone solvent (B1) is methyl ethyl ketone.

[0020] (6) The inkjet ink according to any one of (1) to (5), wherein the dioxolane (B2) is present in an amount of 2 to 90 wt. %, based on the total weight of the inkjet ink.

[0021] (7) The inkjet ink according to any one of (1) to (6), wherein the weight ratio of the dioxolane (B2) to the ketone solvent (B1) ((B2):(B1)) is 0.05:1 to 30:1.

[0022] (8) The inkjet ink according to any one of (1) to (7), wherein the weight ratio of the dioxolane (B2) to the terpene resin (A1) ((B2):(A1)) is 5:1 to 100:1.

[0023] (9) The inkjet ink according to any one of (1) to (8), wherein the solvent system (B) further comprises (B3) a glycol ether.

[0024] (10) The inkjet ink according to (9), wherein the glycol ether (B3) is present in an amount of 0.1 to 20 wt. % based on the total weight of the inkjet ink.

[0025] (11) The inkjet ink according to any one of (1) to (10), wherein the solvent system (B) further comprises (B4) an alcohol solvent.

[0026] (12) The inkjet ink according to (11), wherein the alcohol solvent (B4) is present in an amount of 0.1 to 20 wt. % based on the total weight of the inkjet ink.

[0027] (13) The inkjet ink according to any one of (1) to (12), further comprising (A2) a terpene phenol resin.

[0028] (14) The inkjet ink according to (13), wherein the terpene phenol resin (A2) is present in an amount of 0.1 to 10 wt. % based on the total weight of the inkjet ink.

[0029] (15) The inkjet ink according to any one of (1) to (14), further comprising (C) a surfactant.

[0030] (16) The inkjet ink according to (15), wherein the surfactant (C) is present in an amount of 0.001 to 4 wt. % based on the total weight of the inkjet ink.

[0031] (17) The inkjet ink according to (15) or (16), wherein the surfactant (C) is a polyether-modified silicone.

[0032] (18) The inkjet ink according to any one of (1) to (17), further comprising (D) a colorant.

[0033] (19) A printed product comprising:

[0034] A substrate and the dried form of the inkjet ink according to any one of (1) to (18) disposed on the substrate.

[0035] (20) A method for forming a printed image on a substrate, comprising:

[0036] applying the inkjet ink of any one of (1) to (18) onto a substrate using a thermal inkjet print head; and

[0037] The inkjet ink is dried. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The foregoing paragraphs are provided by way of general introduction and are not intended to limit the scope of the appended claims. The described embodiments, together with further advantages, will be best understood by reference to the following detailed description when considered in conjunction with the accompanying drawings, wherein:

[0039] Figure 1 Shown are spray distance ratings for alphanumeric sequences with a "good" rating (clearly readable, sharp and well-defined image), an "acceptable" rating (readable, mostly clear, but with some blurring or slight loss of edge definition), and a "poor" rating (unreadable, lacking clarity and poorly defined);

[0040] Figure 2 The open seal time evaluations are shown as "good" rating (no missing / unclear lines in the thin line image), "acceptable" rating (1 or 2 missing / unclear lines in the thin line image) and "poor" rating (more than 2 missing / unclear lines in the thin line image). DETAILED DESCRIPTION

[0041] In the following description, it is 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.

[0042] Unless otherwise specified, the phrase "substantially free" describes that the amount of a particular 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.

[0043] As used herein, the term "optional" or "optionally" means that the subsequently described event may or may not occur, or the subsequently described ingredient may or may not be present (eg, 0 wt. %).

[0044] As used herein, unless otherwise indicated, the term "alkyl" refers to a straight chain, branched chain or cyclic aliphatic moiety having at least 1, preferably at least 2, preferably at least 3, preferably at least 4 carbon atoms, and up to 22, preferably up to 20, preferably up to 18, preferably up to 12, preferably up to 8 carbon atoms. The example of alkyl includes but is 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 (guerbet) type alkyl (for example, 2-methylpentyl, 2-ethylhexyl, 2-propylheptyl, 2-butyloctyl, 2-pentylnonyl, 2-hexyldecyl, 2-heptylundecyl, 2-octyldodecyl, 2-nonyltridecyl, 2-decyltetradecyl and 2-undecylpentadecyl).Cycloalkyl is a kind of cyclized alkyl.Exemplary cycloalkyl includes but is not limited to cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, norbornyl and adamantyl.

[0045] As used herein, the term "fat" describes a compound having a long-chain (linear) hydrophobic portion consisting of hydrogen and 8 to 22 carbon atoms, which may be fully saturated or partially unsaturated.

[0046] As used herein, the term "aryl" refers to aromatic groups containing only carbon in the aromatic ring, for example, phenyl, biphenyl, naphthyl, anthracenyl, and the like.

[0047] As used herein, the term "aralkyl" refers to a straight chain, branched, or cyclic alkyl group (as defined above) substituted by an aryl group (as defined above), which itself may be optionally substituted by an alkyl group, examples of which 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.

[0048] The term "(meth)acrylate" is used herein to refer to both acrylate and methacrylate groups. In other words, this term should be understood as meaning that the "meth" is optional. Furthermore, the term "(meth)acrylate" is generally used to refer to both acrylic and acrylate-based compounds.

[0049] Throughout this specification, unless otherwise specified, the term "boiling point" (bp) refers to the boiling point of a liquid measured at atmospheric pressure at sea level (ie, 760 mmHg or 1 atmosphere), also known as the normal boiling point.

[0050] The term "opening behavior" herein refers to the ability of an inkjet ink to be easily ejected from a print head when exposed to air for a long time. The "opening time" of an inkjet ink refers to the time that an inkjet print head may remain unblocked before the printer nozzle no longer ejects normally, which may be due to a blockage or clogging when resuming printing. Typically, due to solvent loss, ink crusting and / or scaling of various ink components in and / or around any nozzle, the nozzle may be blocked (i.e., hindered, slowed) or clogged (i.e., hindered, 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 have an adverse effect on print quality. When the nozzle orifice is clogged, it may be substantially or completely blocked. Because the nozzle is clogged, the ink droplets may not be able to pass through the affected nozzle. Therefore, the criterion for measuring nozzle non-jetting is whether the ink is misdirected through the nozzle orifice to a lesser or greater extent, or is completely clogged, which can be measured by visually inspecting the printed image.

[0051] As used herein, the term "jetting distance" is defined as the distance between the printhead and the substrate surface that can be used while still achieving the desired printed image quality.

[0052] inkjet inks

[0053] The present disclosure relates to inkjet inks that have suitable physical and chemical stability at both ambient temperature and printhead operating temperature, jet reliably, have an extended open time, while still drying quickly after application to a substrate, and are capable of thermal inkjet printing at long jetting distances (e.g., up to 10 mm).

[0054] The inkjet ink of the present disclosure generally includes the following components: (A1) a terpene resin; and (B) a solvent system comprising (B1) a ketone solvent having a boiling point below 120° C. and (B2) a dioxolane.

[0055] The inkjet inks of the present disclosure may also optionally include one or more of (A2) terpene phenolic resins, (B3) glycol ethers, and / or (B4) alcohol solvents as part of the solvent system (B); (C) surfactants; (D) colorants, and (E) additives.

[0056] (A) Resin

[0057] The inkjet ink of the present disclosure is formulated with a terpene resin (A1). Typically, the terpene resin (A1) is used in an amount of at least 0.1 wt.%, preferably at least 0.2 wt.%, preferably at least 0.4 wt.%, preferably at least 0.6 wt.%, more preferably at least 0.8 wt.%, even more preferably at least 0.9 wt.%, and still more preferably at least 1 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.%, preferably at most 5 wt.%, more preferably at most 4 wt.%, even more preferably at most 3 wt.%, and still more preferably at most 2 wt.%, based on the total weight of the inkjet ink.

[0058] The terpene resin (A1) of the present disclosure refers to an oligomer or polymer having at least 95 wt.%, preferably at least 96 wt.%, more preferably at least 97 wt.%, further preferably at least 98 wt.%, still more preferably at least 99 wt.%, even more preferably at least 99.5 wt.%, and further preferably 100 wt.% of constituent units derived from polymerizable terpenes, based on the total constituent units (100 wt.%) of the terpene resin (A1). Terpene has a basic skeleton (C5H8) p , where p is a positive integer representing the number of isoprene units bonded consecutively from head to tail. For example, hemiterpenes (p = 1) have a C5H8 skeleton, monoterpenes (p = 2) have a C 10 H 16 Skeleton, sesquiterpenes (p=3) have C 15 H 24 Skeleton, etc.

[0059] In some embodiments, the terpene resin (A1) is based on monoterpene monomer units. The monoterpene can be a linear monoterpene (e.g., myrcene, ocimene, etc.), a monocyclic monoterpene (e.g., limonene, γ-terpinene, α-phellandrene, β-phellandrene, terpinolene, etc.), or a bicyclic monoterpene (e.g., 3-carene, α-pinene, β-pinene, α-fenchene, camphene, etc.), including various stereoisomers thereof and mixtures thereof. In some embodiments, the monoterpene is a monocyclic monoterpene, particularly preferably limonene. In a preferred embodiment, the monoterpene is a bicyclic monoterpene, particularly preferably 3-carene, α-pinene, β-pinene and camphene, more preferably α-pinene and / or β-pinene, even more preferably α-pinene.

[0060] Preferred inkjet inks are those formulated with a terpene resin (A1) made from the polymerization or oligomerization of α-pinene. As known to those skilled in the art, such terpene resins can be readily obtained, for example, by catalytic polymerization / oligomerization (in solution) of α-pinene monomers, which in turn are typically derived from the fractionation of gums and sulfate turpentines obtained from pine trees such as Pistaciaterebinthus, Pinus pinaster, Pinus halepensis, Pinus massoniana, Pinus merkusii, Pinus palustris, Pinus taeda, and Pinus ponderosa.

[0061] In a preferred embodiment, the terpene resin (A1) is a homopolymer made of α-pinene, and its α-pinene content (constituent 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.%, and still more preferably 100 wt.%, based on the total constituent units (100 wt.%) of the terpene resin (A1). Although the terpene resin (A1) of the present disclosure may include a small amount of other constituent units in addition to the constituent units derived from α-terpene monomers, the amount of other (e.g., non-terpene-based) constituent units is preferably less than 5 wt.%, preferably less than 3 wt.%, preferably less than 1 wt.%, more preferably less than 0.5 wt.%, even more preferably less than 0.1 wt.%, and still more preferably 0 wt.%, based on the total constituent units (100 wt.%) of the terpene resin (A1).

[0062] In some embodiments, the terpene resin (A1) is a homopolymer made of β-pinene, which has a β-pinene component (constituent unit derived from β-pinene) of at least 95 wt.%, preferably at least 96 wt.%, preferably at least 97 wt.%, preferably at least 98 wt.%, preferably at least 99 wt.%, preferably at least 99.5 wt.%, even more preferably at least 99.9 wt.%, and more preferably 100 wt.%, based on the total constituent units (100 wt.%) of the terpene resin (A1). Although the terpene resin (A1) of the present disclosure may include a small amount of other constituent units in addition to the constituent units derived from the β-terpene monomer, the amount of other (e.g., non-terpene-based) constituent units is preferably less than 5 wt.%, preferably less than 3 wt.%, preferably less than 1 wt.%, more preferably less than 0.5 wt.%, even more preferably less than 0.1 wt.%, and even more preferably 0 wt.%, based on the total constituent units (100 wt.%) of the terpene resin (A1).

[0063] Both polymeric and oligomeric forms of the terpene resin (A1), including combinations thereof, can be used herein. Typically, the number average molecular weight (M) of the terpene resin (A1) used herein is n ) 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 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, yet more preferably at most 790 g / mol.

[0064] The terpene resin (A1) may be in the form of a solid or liquid at room temperature. When in solid form, the terpene resin (A1) used herein can be classified according to its 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 a sample pan held in a horizontal ring is pushed downward a distance of 1 inch (25.4 mm) under the weight of a steel ball when the sample is heated at a specified rate in a glycerin bath. For example, the ring-and-ball softening point can be determined according to JIS B7410 (JIS B7410 is incorporated herein by reference in its entirety), measuring apparatus: automatic ring-and-ball softening point; tester: ASP-MGK2, manufactured by MEITECH Company Ltd.; heating rate: 5°C / min; temperature at which heating is started: 40°C; measuring solvent: glycerin. Terpene resins (A1) having various softening points can be used herein, for example, a softening point of at least 20°C, preferably at least 22°C, 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 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, yet more preferably at most 135°C. In a preferred embodiment, the terpene resin (A1) has a softening point of 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 more preferably at most 28°C.

[0065] The bromine number is the amount of bromine (Br2) absorbed by 100 grams of a sample, in grams, and is an indicator of the degree of unsaturation of the sample. In some embodiments, the terpene resin (A1) used in the inkjet ink has a bromine number of 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, and 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, and still more preferably at most 30, although terpene resins (A1) having bromine numbers higher or lower than these values ​​(e.g., hydrogenated terpene resins (A1)) may also be used in the disclosed inkjet inks.

[0066] The inkjet ink of the present disclosure can be formulated with a single type of terpene resin (A1), or with a combination of two or more terpene resins. Examples of the terpene resins (A1) that can be used in the inkjet ink herein, alone or in combination, include, but are not limited to, PICCOLYTE A115 (ring and ball SP = 112-118°C, bromine number = 31.5), PICCOLYTE A125 (ring and ball SP = 122-128°C, bromine number = 31.5), PICCOLYTE A135 (ring and ball SP = 132-138°C, bromine number = 27), PICCOLYTE A135 PLUS (ring and ball SP = 132-138°C), PICCOLYTE AO PLUS (oligomer, liquid), PICCOLYTE A25 (ring and ball SP = 22-28°C), and PINOVA RESIN 2495 (ring and ball SP = 132-138°C, bromine number = 27), all available from Pinova and made from high-purity α-pinene; and PICCOLYTE A135 PLUS (ring and ball SP = 132-138°C), PICCOLYTE AO PLUS (oligomer, liquid). S25 (made from high purity β-pinene, ring and ball SP = 22-28°C, bromine number 19) A particularly preferred terpene resin (A1) for use in the disclosed inkjet inks is PICCOLYTE A25.

[0067] It has been found that a terpene resin (A1) provides excellent open seal time when used in combination with a ketone solvent (B1) having a boiling point below 120°C and a dioxolane (B2). Without being bound by theory, it is believed that the terpene resin (A1) improves the open seal behavior of inkjet inks by forming a thin "skin" or film covering within the printhead nozzle, thereby forming a temporary seal that prevents or reduces solvent loss during periods of inactivity, but the "skin" is easily broken once printing operations resume. The polarity of the terpene resin (A1) is believed to be high enough for vehicle solubility, but not high enough to inhibit the formation of the "skin" due to its strong interaction with the solvent system.

[0068] In addition to the terpene resin (A1), the inkjet ink disclosed herein can optionally be formulated with a terpene phenolic resin (A2). When used, the amount of terpene phenolic resin (A2) can be at least 0.1 wt.%, preferably at least 0.2 wt.%, preferably at least 0.4 wt.%, preferably at least 0.6 wt.%, more preferably at least 0.8 wt.%, even more preferably at least 0.9 wt.%, and more preferably at least 1 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.%, preferably at most 5 wt.%, more preferably at most 4 wt.%, even more preferably at most 3 wt.%, and even more preferably at most 2 wt.%. Preferably, the amount of terpene phenolic resin (A2) (in wt.%) is less than or equal to the amount of terpene resin (A1) in the inkjet ink. In some embodiments, the inkjet ink is substantially free of terpene phenolic resin (A2).

[0069] Terpene-phenol resin (A2) is a copolymerization product of one or more phenolic compounds alkylated with one or more terpenes. As known to those skilled in the art, such resins can be readily obtained by copolymerizing phenolic compounds and terpene monomers under the catalytic action of a strong acid, a metal salt with condensation properties, bleaching earth, a Friedel-Craft catalyst, or a strong Lewis acid (e.g., boron trifluoride).

[0070] Although the terpene phenol resin (A2) of the present disclosure may include a small amount of other constituent units in addition to the constituent units derived from phenolic compounds and the constituent units derived from terpenes, the amount of other (e.g., non-phenolic and non-terpene-based) constituent units based on the total constituent units (100 wt.%) of the terpene phenol resin (A2) is preferably less than 5 wt.%, preferably less than 4 wt.%, preferably less than 3 wt.%, preferably less than 2 wt.%, more preferably less than 1 wt.%, even more preferably less than 0.5 wt.%, and even more preferably 0 wt.%.

[0071] Terpene phenol resin (A2) can be formed by using any terpene with at least one olefinic double bond that can be alkylated by phenolic compounds. In some embodiments, terpene phenol resin (A2) is formed using monoterpene monomer units. Monoterpene can be a straight-chain 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 its various stereoisomers and mixtures thereof. In some embodiments, monoterpene is a monocyclic monoterpene, particularly preferably limonene. In a preferred embodiment, monoterpene is a bicyclic monoterpene, particularly preferably 3-carene, α-pinene, β-pinene and camphene, more preferably α-pinene and / or β-pinene.

[0072] The phenolic compound has at least one hydroxyl group directly bonded to a benzene ring. All monovalent or polyvalent phenolic compounds can be used to prepare the terpene phenol resin (A2) described herein, provided that the phenolic compound has at least two replaceable hydrogen atoms in the ortho and / or para positions relative to the at least one hydroxyl group. In other words, the phenolic compound should be capable of undergoing polyalkylation (e.g., dialkylation) with a terpene and, therefore, should have at least two available ortho / para positions for alkylation relative to the at least one hydroxyl group.

[0073] In a preferred embodiment, the phenolic compound is phenol, which is considered to be a parent unsubstituted phenolic compound (i.e., containing one hydroxyl group directly bonded to the benzene ring and no other substitutions). Alternatively, the phenolic compound may be substituted at up to three positions in addition to the phenolic hydroxyl group, wherein one, two or three aromatic hydrogens of the phenol are replaced by an equal number of substituents, each substituent being independently selected from the group consisting of 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 groups, more preferably C3-C6 alkoxy groups, such as methoxy, ethoxy and isopropoxy; aryl groups; aralkyl groups, such as benzyl; and halogen groups, such as chlorine, bromine, fluorine and iodine.

[0074] Specific examples of 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 (e.g., 4-isopropylphenol), tert-butylphenol (e.g., 4-tert-butylphenol), pentylphenol (e.g., 4-tert-pentylphenol), heptylphenol (e.g., 4-heptylphenol), octylphenol (e.g., o-octylphenol, p-octylphenol, etc.), nonylphenol ( Such as, 4- (2,4- dimethylhept-3-yl) phenol), decylphenol, dodecylphenol, bisphenols such as diphenolyl propane (bisphenol-A), phenylphenol (such as 3-phenylphenol), cumylphenol, p-methoxyphenol (mequinol), benzyloxyphenol, guaiacol, ethoxyphenol (such as 4-ethoxyphenol), and polyphenolic compounds such as resorcinol, pyrogallol, catechol and hydroquinone, including mixtures of two or more of any of the above. Also included are fused ring phenols, such as naphthol (for example, 1-naphthol, 2-naphthol, etc.) and similar compounds. Preferred terpene phenol resins (A2) are those formed by copolymerization of phenol and one or more α-pinene, β-pinene and limonene.

[0075] The molecular weight of the terpene-phenol resin (A2) can vary depending on the monomers used, the reaction conditions and many other factors, but generally a terpene-phenol resin (A2) having a weight-average molecular weight (Mw) of at least 400 g / mol, preferably at least 500 g / mol, more preferably at least 600 g / mol, even more 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, still more preferably at most 1000 g / mol is used.

[0076] Terpene phenol resins (A2) can be classified based on their softening point (SP), for example according to the Ring and Ball softening point method as described above (for example, according to JIS B7410, which is incorporated herein by reference in its entirety). In some embodiments, the softening point of the terpene phenol resin (A2) is at least 60°C, preferably at least 80°C, preferably at least 90°C, preferably at least 100°C, preferably at least 105°C, more preferably at least 110°C, even more preferably at least 115°C, still more preferably at least 120°C; and at most 160°C, preferably at most 155°C, preferably at most 150°C, preferably at most 145°C, preferably at most 140°C, more preferably at most 135°C, even more preferably at most 130°C, yet more preferably at most 125°C.

[0077] The hydroxyl value (OHV) is defined as the number of milligrams of potassium hydroxide required to neutralize the absorbed acetic acid resulting from the acetylation of 1 gram of a chemical substance containing free hydroxyl groups. Therefore, the hydroxyl value or relative hydroxyl content of the terpene-phenol resin (A2) is directly related to the phenolic compound content of the terpene-phenol resin (A2), with higher hydroxyl values ​​indicating a higher incorporation of phenolic compounds (lower incorporation of terpenes) into 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."

[0078] The hydroxyl value of the terpene phenol resin (A2) used in the disclosed inkjet ink can vary, for example, within the range of 10 mgKOH / g to 150 mgKOH / g. However, in terms of unsealing behavior and compatibility with the solvent system (B), it is preferred that the terpene phenol resin (A2) has a hydroxyl value of at least 10 mgKOH / g, preferably at least 15 mgKOH / g, preferably at least 20 mgKOH / g, preferably at least 22 mgKOH / g, preferably at least 24 mgKOH / g, preferably at least 25 mgKOH / g, preferably at least 28 mgKOH / g, preferably at least 30 mgKOH / g, preferably at least 32 mgKOH / g, preferably at least 34 mgKOH / g, more preferably at least 36 mgKOH / g. OH / g, even more preferably at least 38 mgKOH / g, still more preferably at least 40 mgKOH / g, and a hydroxyl value of at most 80 mgKOH / g, preferably at most 75 mgKOH / g, preferably at most 70 mgKOH / g, preferably at most 65 mgKOH / g, preferably at most 60 mgKOH / g, more preferably at most 55 mgKOH / g, even more preferably at most 50 mgKOH / g, yet more preferably at most 45 mgKOH / g, wherein the most preferred hydroxyl value (OHV) is from 20 to 60 mgKOH / g.

[0079] Examples of suitable terpene phenol resins (A2) that may optionally be used alone or in combination in the inkjet inks herein include, but are not limited to, YS POLYSTER products available from Yasuhara Chemical Co. Ltd., such as YS POLYSTER U130 (OHV = 25 mgKOH / g; SP = 130° C.), YS POLYSTER U115 (OHV = 30 mgKOH / g; SP = 115° C.), YS POLYSTER T160 (OHV = 60 mgKOH / g; SP = 160° C.), and YS POLYSTER T145 (OHV = 65 mgKOH / g; SP = 145° C.), and DERTOPHENE products available from DRT / Pinova, such as DERTOPHENE T (OHV = 20-50 mgKOH / g; SP = 95° C.; Mw = 700 g / mol), DERTOPHENE T105 (OHV = 40 mgKOH / g; SP = 105°C; Mw = 700 g / mol), DERTOPHENE T115 (OHV = 50 mgKOH / g; SP = 120°C; Mw = 700 g / mol), and DERTOPHENE T160 (OHV = 60 mgKOH / g; SP = 160°C; Mw = about 1000 g / mol). A particularly preferred terpene phenolic resin (A2) is DERTOPHENE T160.

[0080] In addition to the terpene resin (A1) and any optional terpene phenol resin (A2), the inkjet ink may optionally contain other binder resins / tackifiers / adhesive substances in an amount of 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.%, yet more preferably at most 3 wt.%, based on the total weight of the inkjet ink. Such additional resins, binders, tackifiers or adhesive substances may include, but are not limited to:

[0081] Rosin resins, for example, rosin resins derived from gum rosin, wood rosin and tall oil rosin (whose main components are resin acids such as abietic acid, palustric acid, neoabietic acid, pimaric acid, isopimaric acid and / or dehydroabietic acid), including rosin resins modified by esterification, hydrogenation (including partial hydrogenation), dimerization and / or other modifications / functionalizations (for example, by Diels-Alder reaction with unsaturated diacids such as maleic acid or fumaric acid / anhydride, reduction of carboxylic acids to the 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 composed primarily of abietic or pimaric acid-type resin acids reacted with alcohols (e.g., glycerol, pentaerythritol, ethylene glycol, diethylene glycol, triethylene glycol, methanol, etc.), and optionally hydrogenated or partially hydrogenated, with particular reference to the HARIESTER products supplied by Harima Chemicals, Inc., STAYBELITE ESTER 10-E and PERMALYN 6110, respectively, available from Eastman, SUPER ESTER A-125, SUPER ESTER A-75, PENSEL D-125, PINECRYSTAL KE-359 available from Arakawa Chemical Industries, Ltd., and FORAL 85, FORAL 95 available from Pinova. 105, HERCOLYN products, PEXALYN products, and PENTALYN products; (2) hydrogenated acidic rosins such as FORAL AX and FORAL DX, respectively, available from Pinova; (3) partially hydrogenated acidic rosins such as STAYBELITERESIN-E, available from Eastman, and STAYBELITE and STAYBELITE A, respectively, available from PINOVA; (4) dimerized rosins such as POLY-PALE partially dimerized rosins available from Eastman; and (5) functionalized rosin resins such as esters of rosins modified with maleic anhydride (e.g., glycerides) or rosins subjected to carboxylic acid reducing conditions, with particular mention of LEWISOL 28-M and Abitol-E hydrogenated abietic alcohols, respectively, available from Eastman;

[0082] - phenolic resins (ie, copolymers of phenolic compounds and formaldehyde), for example, novolak resins such as PHENOLITE TD-2131 and PHENOLITE TD-2090 available from DIC Corp.;

[0083] - 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;

[0084] - Epoxy resins, including sulfonamide-modified epoxy resins, such as AD-PRO MTS available from Rit-Chem;

[0085] (Meth)acrylates and styrene / (meth)acrylic 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 Palmer Holland, PARALOID B-72 available from Dow Chemical, USA, and ELVACITE 2013 available from Lucite Inc.;

[0086] - Polyurethane resins, such as those formed by the reaction of (i) a polyol and (ii) a diisocyanate, wherein (i) the polyol includes, but is not limited to, ethylene glycol, propylene glycol, propanediol, butanediol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, polyester polyols (e.g., 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 polyols), and (ii) the diisocyanate includes, but is 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 600, available from Lubrizol. 202 and SANCURE 20025F;

[0087] - polyvinyl butyral resins, such as PIOLOFORM BN 16 and MOWITAL B20H available from Kuraray America, Inc.;

[0088] - polyhydroxystyrene resins, for example poly(p-hydroxystyrene) from DuPont;

[0089] - vinyl resins such as UCARVYHH, VMCH, VMCA and VAGF available from The Dow Chemical Company, and VINNOL E15 / 45, H14 / 36, E15 / 45M and E16 / 40A available from Wacker Chemie AG, Germany;

[0090] - Formaldehyde resins, including sulfonamide-modified formaldehyde resins, such as p-toluenesulfonamide formaldehyde resin, melamine formaldehyde resin, and sulfonamide-modified melamine formaldehyde resin;

[0091] - cellulose ester resins, such as cellulose acetate butyrate (CAB-551-0.01) available from Eastman;

[0092] - as well as polyesters, sulfonated polyesters, gums, cellulose ethers, nitrocellulose resins, polymaleic anhydride, acetal polymers, styrene / butadiene copolymers, ketone-aldehyde resins and polyketone resins;

[0093] - etc., including mixtures thereof.

[0094] In some embodiments, the inkjet ink is substantially free of additional binder resins / tackifiers / adhesive substances, such as those mentioned above, other than the terpene resin (A1) and any optional terpene phenolic resin (A2). In some embodiments, the inkjet ink comprises a combination of a terpene resin (A1) and a terpene phenolic resin (A2), and is preferably substantially free of additional resins, binders, tackifiers, or adhesive substances. In some embodiments, the terpene resin (A1) 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 rosins, dimerized rosins, and other functionalized / modified rosin resins.

[0095] (B) Solvent system

[0096] In many printing processes using solvent-based inks, particularly thermal inkjet printing, the selection of an appropriate solvent system can impact the reliability of the printing process, the performance / appearance of the printed ink product, and the efficiency of the overall printing process. For example, in thermal inkjet printing, the choice of solvent system can 1) aid in bubble formation during jetting, thereby producing reliable inkjet, 2) affect the stability / volatility of the inkjet ink by altering the interaction dynamics between the solvent and various inkjet ink components, thereby affecting debonding behavior, agglomeration, and / or droplet trajectory, 3) affect the adhesion, rub resistance, and optical density characteristics of the printed image after drying through 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 reduced amounts, 4) affect the drying time after application or the equipment required to dry the applied ink, and / or 5) affect droplet dynamics.

[0097] In view of the above, inkjet inks having a solvent system (B) comprising one or more (B1) ketone solvents are particularly preferred herein. The inclusion of the ketone solvent (B1) can aid in the solvation of the inkjet ink components, provide polar compatibility with the terpene resin (A1) to achieve the desired decapping behavior, and provide an inkjet ink with acceptable volatility to achieve the purpose of drying time.

[0098] The amount of ketone solvent (B1) used in the inkjet ink can vary widely, for example, at least 1 wt.%, preferably at least 3 wt.%, preferably at least 5 wt.%, preferably at least 10 wt.%, preferably at least 15 wt.%, preferably at least 20 wt.%, preferably at least 25 wt.%, preferably at least 30 wt.%, preferably at least 35 wt.%, more preferably at least 40 wt.%, even more preferably at least 45 wt.%, still more preferably at least 50 wt.%; and at most 90 wt.%, preferably at most 85 wt.%, preferably at most 80 wt.%, preferably at most 75 wt.%, more preferably at most 70 wt.%, more preferably at most 65 wt.%, even more preferably at most 60 wt.%, yet more preferably at most 55 wt.%, based on the total weight of the inkjet ink.

[0099] Preferred ketone solvents (B1) are those having a boiling point of less than 120° C., preferably less than 115° C., preferably less than 110° C., preferably less than 105° C., preferably less than 100° C., preferably less than 95° C., more preferably less than 90° C., even more preferably less than 85° C., still more preferably less than 80° C. When a ketone solvent (B1) having a boiling point of not more than the above upper limit is used, a fast drying time and a favorable desealing time can be achieved.

[0100] The ketone solvent (B1) may contain 3, 4, 5 or 6 carbon atoms. Examples of ketone solvents that can be used alone or in combination in the disclosed inkjet ink include, but are not limited to, acetone, methyl ethyl ketone (MEK), 3-pentanone, methyl n-propyl ketone, methyl isopropyl ketone, ethyl isopropyl ketone and methyl isobutyl ketone, preferably methyl ethyl ketone.

[0101] The solvent system (B) of the disclosed inkjet ink is also formulated with (B2) dioxolane. Dioxolane (1,3-dioxolane) is a heterocyclic acetal with the chemical formula (CH2)2O2CH2. Surprisingly, the addition of dioxolane (B2) has been found to improve the jetting distance of the inkjet ink, enabling the production of readable images at jetting distances of, for example, 8-15 mm. On the other hand, the inkjet inks described herein that do not contain dioxolane do not provide readable images at jetting distances exceeding 4 mm.

[0102] Without being bound by theory, it is believed that dioxolane affects jet distance by changing the droplet dynamics of the ejected inkjet droplets through a combination of density and surface tension factors. For example, compared to ketone solvents such as methyl ethyl ketone (0.805 g / mL at 25°C), dioxolane has a relatively high density (1.06 g / mL at 25°C), and it is believed that this higher density provides more precise directionality and stability for the inkjet droplets to combat airflow, turbulence, and / or vortices within the print gap, which may otherwise negatively affect droplet position. In addition, compared to ketone solvents such as methyl ethyl ketone (24.0 mN / m at 25°C), dioxolane has a relatively high surface tension (34.3 mN / m at 25°C), and it is believed that the higher surface tension provides more spherical and aerodynamic ink drops that can travel a greater distance while maintaining the desired droplet position. In addition to droplet dynamics, dioxolane was found to be a unique solvent in terms of solubility / compatibility with the resin (A) in the disclosed inkjet inks.

[0103] Based on the total weight of the inkjet ink, the amount of dioxolane (B2) suitable for obtaining the desired jetting distance can be at least 2 wt.%, preferably at least 4 wt.%, preferably at least 5 wt.%, preferably at least 10 wt.%, preferably at least 15 wt.%, preferably at least 20 wt.%, preferably at least 25 wt.%, preferably at least 30 wt.%, preferably at least 35 wt.%, more preferably at least 40 wt.%, even more preferably at least 45 wt.%, still more preferably at least 50 wt.%; and at most 90 wt.%, preferably at most 85 wt.%, preferably at most 80 wt.%, preferably at most 75 wt.%, preferably at most 70 wt.%, more preferably at most 65 wt.%, even more preferably at most 60 wt.%, and still more preferably at most 55 wt.%.

[0104] In a preferred embodiment, the ketone solvent (B1) and the dioxolane (B2) together constitute the majority of the solvent system (B) used in the inkjet ink, i.e., the combined weight of the ketone solvent (B1) and the dioxolane (B2) may be 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.%, based on the total weight of the solvent system (B).

[0105] Regarding the ketone solvent (B1), it is preferred that the weight ratio of dioxolane (B2) to ketone solvent (B1) ((B2):(B1)) of the inkjet ink is from 0.05:1, preferably from 0.07:1, preferably from 0.1:1, preferably from 0.3:1, preferably from 0.5:1, more preferably from 0.7:1, even more preferably from 0.9:1, still more preferably from 1:1, and at most 30:1, preferably at most 25:1, preferably at most 20:1, preferably at most 15:1, preferably at most 10:1, more preferably at most 5:1, even more preferably at most 3:1, yet more preferably at most 2:1.

[0106] With regard to the terpene resin (A1), it is preferred that the weight ratio of dioxolane (B2) to terpene resin (A1) ((B2):(A1)) of the inkjet ink is at least 5:1, preferably at least 10:1, preferably at least 20:1, preferably at least 30:1, preferably at least 40:1, preferably at least 50:1, preferably at least 55:1, more preferably at least 60:1, even more preferably at least 65:1, still more preferably at least 70:1; and at most 100:1, preferably at most 95:1, preferably at most 90:1, more preferably at most 85:1, even more preferably at most 80:1, yet more preferably at most 75:1.

[0107] Solvent system (B) may also optionally include a glycol ether (B3) to further improve the unsealing performance without significantly deteriorating the ink drying time. The glycol ether (B3) may be a monoalkyl ether, a dialkyl ether, a monoalkyl monoester ether, or a combination thereof. Preferably, the glycol ether (B3) is a monoalkyl monoester ether, i.e., a glycol compound in which one hydroxyl group is etherified and another hydroxyl group is esterified. The glycol ether (B3) may contain at least 3 carbon atoms, preferably at least 4 carbon atoms, more preferably at least 5 carbon atoms, even more preferably at least 6 carbon atoms; and at most 12 carbon atoms, preferably at most 10 carbon atoms, and more preferably at most 8 carbon atoms.

[0108] In some embodiments, the solvent system (B) can be formulated with a mixture of glycol ethers (B3), for example, the weight ratio of the first glycol ether to the second glycol ether is at least 1:5, preferably at least 1:4, more preferably at least 1:3, even more preferably at least 1:2, still more preferably at least 1:1; and at most 5:1, preferably at most 4:1, more preferably at most 3:1, even more preferably at most 2:1.

[0109] Acceptable examples of glycol ethers (B3) that may be optionally included in the disclosed inkjet inks include, but are not limited to, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol n-propyl ether, ethylene glycol mono-tert-butyl ether, ethylene glycol monobutyl ether, ethylene glycol monoisobutyl ether, diethylene glycol monomethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-tert-butyl ether, propylene glycol mono-n-propyl ether, propylene glycol monoisopropyl ether, propylene glycol mono-n-butyl ether, dipropylene glycol monomethyl ether, ethylene glycol mono-n-butyl ether acetate, propylene glycol methyl ether acetate, diethylene glycol mono-n-butyl ether acetate, diethylene glycol monoethyl ether acetate, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dipropylene glycol mono-n-propyl ether, and mixtures thereof.

[0110] In terms of improving the unsealing performance of the inkjet ink without significantly extending the drying time of the ink, the boiling point of the glycol ether (B3) is preferably below 214°C, preferably below 210°C, more preferably below 205°C, even more preferably below 200°C, and still more preferably below 195°C.

[0111] In view of the above, ethylene glycol mono-n-butyl ether acetate, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol mono-n-propyl ether and propylene glycol mono-n-propyl ether are preferred, with ethylene glycol mono-n-butyl ether acetate being particularly mentioned.

[0112] When used, the glycol ether (B3) may be present in the inkjet ink in an amount of at least 0.1 wt.%, preferably at least 0.3 wt.%, preferably at least 0.5 wt.%, preferably at least 0.7 wt.%, more preferably at least 1 wt.%, even more preferably at least 1.5 wt.%, and still more preferably at least 2 wt.%, and at most 20 wt.%, preferably at most 15 wt.%, more preferably at most 10 wt.%, even more preferably at most 5 wt.%, and still more preferably at most 3 wt.%, based on the total weight of the inkjet ink. The weight ratio of the ketone solvent (B1) to the glycol ether (B3) may be adjusted for the desired drying time and decapping time, but is typically at least 1:1, preferably at least 2:1, more preferably at least 5:1, even more preferably at least 10:1, and yet more preferably at least 15:1; and at most 50:1, preferably at most 40:1, more preferably at most 30:1, even more preferably at most 25:1, and yet more preferably at most 20:1.

[0113] The solvent system (B) may also optionally contain (B4) an alcohol solvent. The inclusion of an alcohol solvent (B4) may aid in solvation of the inkjet ink components, particularly when a terpene phenol resin (A2) is used, and aid in jettability, among other benefits.

[0114] The alcohol solvent (B4) may contain at least 1 carbon atom, preferably at least 2 carbon atoms, more preferably at least 3 carbon atoms, and up to 8 carbon atoms, preferably up to 6 carbon atoms, more preferably up to 4 carbon atoms. Preferred alcohol solvents (B4) are alcohol solvents having a boiling point below 120° C., preferably below 115° C., preferably below 110° C., more preferably below 105° C., even more preferably below 100° C., still more preferably below 98° C.

[0115] Suitable examples of alcohol solvents that can be used alone or in combination in the disclosed inkjet inks include, but are not limited to, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-pentanol, 3-pentanol, and tert-pentanol, with particular mention being made of 1-propanol.

[0116] When used, the alcohol solvent (B4) may be present in the inkjet ink in an amount of at least 0.1 wt.%, preferably at least 0.3 wt.%, preferably at least 0.5 wt.%, more preferably at least 0.7 wt.%, even more preferably at least 0.9 wt.%, yet even more preferably at least 1 wt.%, and at most 20 wt.%, preferably at most 15 wt.%, still more preferably at most 10 wt.%, more preferably at most 5 wt.%, even more preferably at most 3 wt.%, yet more preferably at most 2 wt.%, based on the total weight of the inkjet ink. While the amount of alcohol solvent (B4) can be adjusted, for example, to provide a desired level of solvation, preferred inkjet inks have a weight ratio of terpene resin (A1) to alcohol solvent (B4) ((A1):(B4)) of at least 1:5, preferably at least 1:4, more preferably at least 1:3, even more preferably at least 1:2, still more preferably at least 1:1; and at most 5:1, preferably at most 4:1, more preferably at most 3:1, even more preferably at most 2:1.

[0117] Other organic solvents may optionally be used as part of the solvent system (B) herein, examples of which include, but are not limited to, ethers (non-glycol ethers), including ethers containing 4 to 8 carbon atoms (e.g., diethyl ether, dipropyl ether, methyl tert-butyl ether, dibutyl ether, dioxane, and tetrahydrofuran); esters, including esters having 3 to 8 carbon atoms (e.g., methyl acetate, ethyl acetate, n-butyl acetate, methyl lactate, ethyl lactate); alkanes (e.g., pentane, hexane, and heptane); and the like; and mixtures of two or more thereof. When present, the other organic solvent may be present in an amount of 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.%, and still more preferably up to 1 wt.%, based on the total weight of the inkjet ink.

[0118] In a preferred embodiment, the inkjet ink is substantially free of solvents having a boiling point higher than 220°C, preferably free of solvents having a boiling point higher than 210°C, more preferably free of solvents having a boiling point higher than 200°C, and even more preferably free of solvents having a boiling point higher than 195°C. In some embodiments, the inkjet ink is substantially free of ketone solvents having a boiling point higher than 120°C, examples of which include but are not limited to 3-hexanone, methyl n-butyl ketone, and cyclohexanone. In some embodiments, the inkjet ink is substantially free of glycol ethers (B3). In some embodiments, the inkjet ink is substantially free of alcohol solvents (B4). In a preferred embodiment, the solvent system (B) consists of a ketone solvent (B1), a dioxolane (B2), a glycol ether (B3), and an alcohol solvent (B4).

[0119] In a preferred embodiment, the inkjet inks of the present disclosure are substantially non-aqueous, meaning that no water is added to the inkjet ink, other than incidental amounts of moisture derived from ambient conditions. In such cases, the inkjet ink may have less than 1 wt.%, 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.%, and even more preferably 0 wt.%, based on the total weight of the inkjet ink.

[0120] Surfactant (C)

[0121] The inkjet inks of the present disclosure may optionally include (C) a surfactant, which can, for example, provide anti-blocking, ink acceptance, leveling, anti-sag, increased surface slip and / or substrate wetting properties, as well as other advantages, without sacrificing the unsealing and jetting distance performance of the inkjet ink. When used, the surfactant (C) may be used in an amount of at least 0.001 wt.%, preferably at least 0.005 wt.%, preferably 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.%, still more preferably at least 0.1 wt.%, and up to 4 wt.%, preferably up to 3 wt.%, preferably up to 2 wt.%, preferably up to 1 wt.%, preferably up to 0.8 wt.%, preferably up to 0.6 wt.%, more preferably up to 0.4 wt.%, even more preferably up to 0.3 wt.%, and still more preferably up to 0.2 wt.%, based on the total weight of the inkjet ink.

[0122] Examples of surfactants (C) that can be used herein alone or in combination include, but are not limited to:

[0123] - polysiloxanes, including organomodified 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)), each available from BYK Additives & Instruments;

[0124] - acrylic silicone 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 KK);

[0125] - polyether-modified silicones, including block copolymers having a pendant graft structure formed from a linear or branched polydimethylsiloxane backbone containing one or more polyether side chains and optionally one or more fatty alkyl side chains;

[0126] - Fluoropolymers such as FC-4430 and FC-4432, available from 3M Company;

[0127] - photocrosslinkable silicone acrylates or silicone polyether acrylates, for example TEGO RAD 2100, TEGO RAD 2200, TEGO RAD 2250, TEGO RAD 2300 (silicone polyether acrylates), each available from Evonik Industries, and BYK-UV 3500 and 3530, available from BYK;

[0128] Polyacrylates, including polyacrylate copolymers and crosspolymers, such as BYK-381 and BYK-361N (polyacrylate copolymers), respectively available from BYK, PEMULEN EZ-4U (acrylates / C10-C30 alkyl acrylate crosspolymer) and PEMULEN TR-2 (acrylic acid / C10-C30 alkyl acrylate crosspolymer), each available from Lubrizol;

[0129] - acetylenic diols and acetylenic diol-based gemini surfactants, such as SURFYNOL SEF and DYNOL surfactants, available from Evonik Industries;

[0130] - polysiloxane-based gemini surfactants, such as TEGO TWIN 4100, available from Evonik Industries;

[0131] - nonionic polyethers, for example as substrate-wetting surfactants, for example TEGO WET 510 (hydrophilic polyether substrate-wetting surfactant) available from Evonik Industries;

[0132] - amides or monoalkanolamides of fatty acids, including alkoxylated monoalkanolamides of fatty acids, such as coconut fatty acid monoethanolamide and coconut fatty acid monoethanolamide reacted with 2 to 20 mol of ethylene oxide;

[0133] -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 tridecanol), each available from Stepan, ethylene oxide / propylene oxide copolymers, alkoxylated alkylphenols, and alkyl polyglycosides (APGs), such as those prepared by the reaction between fatty alcohols and glucose;

[0134] - fatty esters such as ethoxylated and / or propoxylated fatty acids (e.g., castor oil with 2 to 40 moles of ethylene oxide), alkoxylated glycerides (e.g., PEG-24 glyceryl monostearate), glycol esters and derivatives thereof, monoglycerides, polyglycerol esters, polyol esters, and sorbitol / sorbitol esters, such as sorbitan monolaurate (e.g., EMASOL L-10V available from Kao) and polysorbates, including mono-, di-, or tri-fatty acid esterified polysorbates, such as TOXIMUL SEE-340 (ethoxylated sorbitan trioleate (20) available from Stepan); and

[0135] - Glycosides of fatty alcohols, for example PLANTASENS NATURAL EMULSIFIER HE 20 (cetearyl glucoside, sorbitanolivate) available from Clariant.

[0136] When the inkjet ink is formulated with a surfactant (C), a particularly preferred surfactant is a polyether-modified silicone. A polyether-modified silicone can be a block copolymer having a pendant graft structure comprising or consisting of (i) a silicone backbone (main chain) and (ii) one or more polyether side chains attached to the silicone backbone, and optionally (iii) one or more fatty alkyl side chains attached to the silicone backbone. Thus, as long as at least one polyether side chain is attached to the silicone backbone, the material meets the definition of a "polyether-modified silicone", regardless of whether other side chain types (e.g., fatty alkyl side chains) are also attached to the silicone backbone. Preferably, in addition to the polyether side chains and the optional fatty alkyl side chains, no other side chains are present in the polyether-modified silicone. As described herein, a "side chain" is not a continuation of the silicone backbone as in a linear block copolymer (e.g., an ABA structure), but is attached to the silicone backbone (main chain) as a pendant graft, thereby forming a branch point on the silicone backbone, and the side chain extends from the silicone backbone via a covalent bond. Preferred polyether-modified silicones are non-hydrolyzable, ie, wherein the side chains are attached to the silicone backbone via Si-C bonds.

[0137] <(i) Silicone Backbone> The silicone backbone can be based on any linear or branched organosilicon polymer or oligomer (polyorganosiloxane) having a variable molecular weight, which can be formed by polymerization and / or polycondensation of appropriately functionalized silanes and has a polysiloxane backbone structure (silicon atoms linked together by oxygen atoms, -Si-O-Si-), wherein alkyl, aryl, and / or aralkyl groups are directly bonded to the (tetravalent) silicon atoms. For example, the polyorganosiloxane backbone can be a linear structure, including but not limited to a polydimethylsiloxane (dimethylsiloxane) backbone (in which 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 a branched structure, with polydimethylsiloxyethyldimethylsiloxane being particularly mentioned.

[0138] <(ii) Polyether Side Chains> The polyether-modified silicone contains at least one polyether side chain based on a polyalkylene glycol oligomer or polymer, such as those formed by ring-opening polymerization of one or more alkylene oxides, most preferably ethylene oxide (EO), propylene oxide (PO), and / or butylene oxide (BO), including copolymers, such as block copolymers thereof. Preferably, the polyether side chain is polyethylene glycol or a polyethylene glycol-polypropylene glycol copolymer extending from the silicone backbone. More preferably, the polyether side chain is a polyethylene glycol side chain (formed solely from ethylene oxide EO).

[0139] Generally, polyether side chains of various lengths can be used, typically the number of moles of alkylene oxide units per side chain is at least 2, preferably at least 3, more preferably at least 4, even more preferably at least 5, still 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 more preferably up to 9, with 3 to 10, preferably 4 to 9, moles of ethylene oxide (EO) units per side chain being particularly preferred.

[0140] 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 terminated by an alkyl group having 1, 2, 3 or 4 carbon atoms (forming a terminal alkyl ether group), particular mention being made of methyl, ethyl, propyl and butyl groups.

[0141] <(iii) Fatty alkyl side chains> The polyether-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, still more preferably up to 14 carbon atoms. Exemplary fatty alkyl side chain groups include, but are not limited to, capryl, nonyl, decyl, undecyl, lauryl, tridecyl, myristyl, pentadecyl, cetyl, palmitoleyl, heptadecyl, stearyl, oleyl, eicosyl, and behenyl, with particular mention being made of lauryl, myristyl, cetyl, and stearyl, preferably lauryl.

[0142] In some embodiments, the polyether-modified silicone is a block copolymer having a pendant graft structure formed from a linear polydimethylsiloxane backbone containing one or more polyether side chains, for example, represented by Formula (IA).

[0143]

[0144] in:

[0145] 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 is at most 500, preferably at most 400, preferably at most 300, more preferably at most 200, even more preferably at most 100, yet more preferably at most 50;

[0146] p represents the number of constitutional units containing a polyether side chain, and is a positive integer, for example, 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 100, preferably at most 80, preferably at most 60, more preferably at most 40, even more preferably at most 20, yet more preferably at most 10; and

[0147] A is a polyether-containing group represented by formula (II)

[0148] -(CH2) w -O-(CH2CH2O) n -(CH2CH(CH3)O) m -Z (II)

[0149] in:

[0150] w is at least 2, preferably at least 3, and at most 6, preferably at most 5, more preferably at most 4, even more preferably w is 3;

[0151] n is 0 or an integer of at least 1, preferably at least 2, more preferably at least 3, even more preferably at least 4, and at most 30, preferably at most 20, more preferably at most 10, even more preferably at most 9, yet more preferably n is 3 to 10;

[0152] m is 0 or an integer up to 30, preferably up to 10, preferably up to 9, preferably up to 5, more preferably up to 2, even more preferably up to 1, still more preferably m is 0; and

[0153] Z is H or an alkyl group having 1 to 4 carbon atoms, preferably H (uncapped).

[0154] In some embodiments, the polyether-modified silicone is a block copolymer having a pendant graft structure formed from a branched polydimethylsiloxane backbone containing one or more polyether side chains and one or more fatty alkyl side chains, for example, represented by formula (IB).

[0155]

[0156] in:

[0157] o, p and A are as described above;

[0158] B is a fatty alkyl group, preferably a fatty alkyl group having at least 10 carbon atoms, preferably at least 12 carbon atoms, and at most 18 carbon atoms, preferably at least 16 carbon atoms, preferably at least 14 carbon atoms, mentioning in particular lauryl, myristyl, cetyl and stearyl;

[0159] q represents the number of constitutional units containing fatty alkyl side chains, and is a positive integer, for example 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 50, preferably at most 40, preferably at most 30, more preferably at most 20, even more preferably at most 10, still more preferably at most 5;

[0160] r represents the branching in the polydimethylsiloxane backbone and is a positive integer, for example a positive integer of at most 50, preferably at most 40, preferably at most 30, preferably at most 20, preferably at most 10, preferably at most 5, more preferably at most 3, even more preferably at most 2, yet even more preferably 1;

[0161] x is a positive integer, for example 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 200, preferably at most 150, preferably at most 100, more preferably at most 75, even more preferably at most 50, more preferably at most 30, even more preferably at most 20, yet more preferably at most 10; and

[0162] y is at least 2 and at most 6, preferably 2.

[0163] Suitable examples of polyether-modified silicones that can be used in the disclosed inkjet inks include, but are not limited to, KF-6013 (PEG-9 dimethicone, uncapped, HLB=10.0), KF-6015 (PEG-3 dimethicone, uncapped, HLB=4.5), KF-6017 (PEG-10 dimethicone, uncapped, HLB=4.5), and KF-6038 (Lauryl PEG-9 Polydimethylsiloxyethyl Dimethicone, uncapped, HLB=3.0), respectively, available from Shin-Etsu Chemical Co., and BYK-307 (polyether-modified polydimethicone) available from BYK Additives & Instruments.

[0164] In some embodiments, the inkjet inks of the present disclosure are substantially free of surfactants (C), such as those listed above.

[0165] (D) Colorant

[0166] It will be readily understood by those skilled in the art that more than one colorant (D) may be optionally included in an inkjet ink to provide a color ink that can be used for a variety of printing purposes, and that the inkjet ink is not limited to any particular color. Any colorant (D) may be used in an inkjet ink to provide a desired color, including dyes, pigments, mixtures thereof, and the like, as long as the colorant (D) is soluble or dispersed in the inkjet ink. Suitable colors include, for example, cyan, magenta, yellow, and key colors (black) ("CMYK"), white, orange, green, light cyan, light magenta, purple, and the like, including spot colors and process colors. Typically, the amount of colorant (D) used may 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.%, more preferably at least 5 wt.%, even more preferably at least 7 wt.%, still more preferably at least 10 wt.%; and at most 20 wt.%, preferably at most 18 wt.%, more preferably at most 16 wt.%, even more preferably at most 14 wt.%, yet more preferably at most 12 wt.%, based on the total weight of the inkjet ink.

[0167] Inkjet inks can be formulated with a variety of dyes, with organic dyes, such as OIL BLACK 860 available from Orient Chemical Industries, and metal complex dyes being particularly preferred.

[0168] Inkjet inks can be formulated with various inorganic and / or organic pigments. In addition to providing color to the inkjet ink, these pigments can also improve the lightfastness, weather resistance, etc. of the printed image.

[0169] (E) Additives

[0170] In addition to the components already mentioned, the inkjet ink may optionally be formulated with various additives (E) to improve various ink properties and performance. For example, the inkjet ink may optionally contain one or more anti-caking agents, stabilizers, humectants, label safers, or other inkjet ink additives known to those of ordinary skill in the art, at levels appropriate in the art.

[0171] Preparation method

[0172] Embodiments of the inkjet inks described herein can be prepared by any suitable technique known to one of ordinary skill in the art, for example, by mixing (A1) a terpene resin and any desired optional ingredients (e.g., (A2) a terpene phenolic resin, (C) a surfactant, (D) a colorant, and / or an additive (E)) with a suitable solvent system (B) comprising (B1) a ketone solvent and (B2) a dioxolane, and optionally (B3) a glycol ether and / or (B4) an alcohol solvent, in any order, and stirring, agitating, and / or homogenizing at a temperature of 20-100° C. for a suitable time to form a homogeneous solution.

[0173] In one experimental example, the terpene resin (A1) can be first combined with the ketone solvent (B1) and the dioxolane (B2), as well as any optional resin (e.g., terpene phenol resin (A2)), the optional alcohol solvent (B4), the optional surfactant (C), or other optional additives (E) in a container, and then stirred for at least 10 minutes, preferably at least 15 minutes, preferably at least 20 minutes, preferably at least 25 minutes, preferably at least 30 minutes, preferably at least 35 minutes, preferably at least 40 minutes, preferably at least 45 minutes. Then, when the glycol ether (B3) is used, it can be added to the resulting mixture and then stirred for at least 10 minutes, preferably at least 15 minutes, preferably at least 20 minutes, preferably at least 25 minutes. Then, the colorant (D) can be added as the final component under continuous mixing, and the solution can be mixed for at least 10 minutes, preferably at least 15 minutes, preferably at least 20 minutes, preferably at least 25 minutes, preferably at least 30 minutes, preferably at least 35 minutes, preferably at least 40 minutes, preferably at least 45 minutes to provide an inkjet ink. The resulting inkjet ink can then be placed into a print cartridge, such as the FUNAITIJ cartridge manufactured by Funai Co., or other printhead suitable for ketone-based inks.

[0174] performance

[0175] The inkjet inks disclosed herein have an extended unsealing time, for example, as measured by printing a fine line image (e.g., a barcode) (1 mm*1 cm, fine line, monochrome bitmap), exposing the inkjet ink to air (unsealing the cartridge) for a specific time (e.g., 30 seconds, 1 minute, 10 minutes, 60 minutes, etc.), reprinting the same fine line image, and comparing the reprinted image after unsealing with the original image to determine whether line loss / line clarity loss has occurred in the fine line image. If no line loss / line clarity loss occurs within the tested time interval, the inkjet ink is rated as "good" for unsealing within the time interval. If there is 1-2 line loss / loss of clarity within the tested time interval, but it is not enough to significantly affect the clarity or readability of the fine line image, the inkjet ink is given an "acceptable" unsealing rating within the time interval. If there are more than 2 line losses / loss of clarity within the tested time interval, the inkjet ink is classified as "poor" within the time interval. Suitable inkjet inks are those that achieve an "acceptable" or "good" deseal classification when desealed (i.e., exposed to air) for 30 seconds or more, preferably 1 minute or more, more preferably 10 minutes or more, even more preferably 30 minutes or more, and still even more preferably 60 minutes or more.

[0176] The inkjet ink disclosed herein also has the feature of long jet distance. The jet distance of the inkjet ink can be measured by printing a test image with increasing distance between the print head and the substrate and evaluating the image quality at each distance. This can include printing an image such as an alphanumeric sequence at various jet distances (e.g., 2mm, 4mm, 6mm, 8mm, and 10mm) and visually evaluating the quality of the printed image in terms of image clarity, edge contours, and accurate droplet position. If the printed image is clear and readable, with clear edge contours and accurate droplet position, the inkjet ink is rated as a "good" jet distance in the jet distance tested. If the printed image is readable, but has some fuzziness, a slight loss of edge contours, and / or a slight loss of droplet position accuracy, the inkjet ink is rated as an "acceptable" jet distance grade in the jet distance tested. If the printed image is unreadable, due to lack of image clarity, unclear edge contours, and / or inaccurate droplet position, the inkjet ink is rated as a "bad" jet distance in the jet distance tested. Preferred inkjet inks are those that maintain a "good" or "acceptable" jetting distance rating for a jetting distance of at least 1 mm, preferably at least 2 mm, preferably at least 3 mm, preferably at least 4 mm, preferably at least 5 mm, preferably at least 6 mm, preferably at least 7 mm, more preferably at least 8 mm, even more preferably at least 9 mm, still more preferably at least 10 mm, and at most 15 mm, preferably at most 14 mm, preferably at most 13 mm, preferably at most 12 mm.

[0177] Another advantage of the disclosed inkjet inks is that they can be easily adjusted and tuned for optical density to meet consumer needs, the requirements of specific applications, and the like. The optical density of an ink can be measured by printing a solid block image (e.g., 1 cm by 10 cm) and reading the optical density with a spectrophotometer (e.g., an X-rite eXact, density / TVI model, sold by X-rite). Since optical density is a measure of reflected or absorbed light drawn into the printed surface, optical density values ​​are dimensionless. Inkjet inks that produce images with an optical density reading below 1.90 are considered to provide low optical density images, while those that provide optical density readings above 1.90 are considered to provide high optical density images. Typical inkjet inks of the present disclosure provide images having an optical density of at least 1.90, preferably at least 2.00, preferably at least 2.10, preferably at least 2.20, preferably at least 2.30, preferably at least 2.40, preferably at least 2.50, and at most 2.70, or preferably at most 2.60, although optical density values ​​above or below these ranges can be produced as desired.

[0178] Printed products

[0179] Inkjet inks can be printed on a variety of substrates, including three-dimensional parts and flat sheets or webs provided in roll form, to produce a wide 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 with long jetting distance capabilities can form printed images on complex three-dimensional substrates, such as those with radial, curved, jagged, corrugated, grooved, bordered, and / or those with structured surfaces (e.g., particulate surfaces), all of which are notoriously difficult substrates due to the long distances the ink must travel to reach all parts of the complex surface. Printed articles can be suitable for use in the fine art, textiles, packaging (e.g., food packaging, pharmaceutical packaging, etc.), lottery, direct mail, commercial forms, and publishing industries, with examples including labels or tags, lottery tickets, publications, packaging (e.g., food packaging, pharmaceutical packaging, blister packaging, various other flexible packaging, etc.), folding cartons, rigid containers (e.g., plastic cups or buckets, glass containers, metal cans, bottles such as PET bottles, jars, and tubes), envelopes, corrugated board, point-of-sale displays, and the like. Particularly preferred printed articles are those having the inkjet ink in dry form arranged on a complex three-dimensional portion of the printed article, for example, where the printed image is located on a grooved or corrugated portion of a plastic container, or on a concave domed bottom of a metal can.

[0180] Inkjet inks can be printed on porous (or penetrable) substrates, examples of which include but are not limited to uncoated paper, wood, film, corrugated board (corrugated cardboard / fiberboard), and fabrics (including but not limited to woven fabrics, nonwoven fabrics, and foil laminated fabrics).

[0181] Inkjet inks can also be printed on non-porous (or impenetrable substrates), for example, various plastics, glass, metals (e.g., steel, aluminum, etc.) and / or impenetrable papers (e.g., coated papers, such as varnish-coated papers), including but not limited to molded plastic or metal parts and flat sheets or rolls of plastic or metal films. Examples include those 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), cellulose triacetate (TAC), polycarbonate, acrylonitrile-butadiene-styrene (ABS), polyacetal, polyvinyl alcohol (PVA) substrates, coated papers such as varnish-coated papers, and metals such as steel and aluminum, etc.

[0182] Method of forming a printed image

[0183] Inkjet printing creates the desired printed image when a precise pattern of dots is ejected from a droplet-generating device called a printhead onto the print medium. The printhead has a precisely formed array of nozzles located on a nozzle plate attached to the inkjet printhead substrate. The inkjet printhead substrate includes an array of firing chambers that receive inkjet ink through fluidic communication with one or more ink reservoirs. Each firing chamber has a resistive element, called a firing resistor, located opposite the nozzle to allow the inkjet ink to pool between the firing resistor and the nozzle. Each resistor element is typically a pad of resistive material, measuring, for example, approximately 35 μm x 35 μm. The printhead is held and protected by an outer packaging called a print cartridge or inkjet pen. When power is applied to a specific resistor element, droplets of inkjet ink are ejected through the nozzles toward the print medium. The ejection of ink drops is typically controlled by a microprocessor, whose signals are transmitted via electrical traces to the resistor elements, thereby creating alphanumeric and other image patterns on the print medium. Because the nozzles are small, typically 10 μm to 40 μm in diameter, it is important to minimize ink clogging. In particular, because thermal inkjet (TIJ) is an open-atmosphere printhead design (the nozzle orifice is open to the atmosphere and there is no valve seal at the orifice to allow ink pressurization), TIJ printing has historically performed poorly during intermittent printing, where deseal time (printing idle time) causes premature drying of the ink in and around the nozzle.

[0184] In one or more embodiments of the present disclosure, a method for forming a printed image by applying an inkjet ink onto a surface of a substrate using a thermal inkjet printhead and drying the inkjet ink is provided. The use of the inkjet ink described herein overcomes the short decapping time (solvent loss rate) typically associated with thermal inkjet processes, while also enabling the application of the inkjet ink from a greater ejection distance than is achievable with conventional inkjet printing systems.

[0185] Any drop-on-demand printhead known to those of ordinary skill in the art of inkjet printing can be used as the printing unit in this method, including continuous printheads, thermal printheads, electrostatic printheads, and acoustic printheads, preferably using a thermal printhead (with a heat converter). Typical parameters, such as print resolution, print speed, printhead pulse heating temperature, drive voltage, and pulse length, can be adjusted according to the specifications of the printhead. The droplet size of the printhead generally suitable for the method herein is in the range of 2 to 80 pL, and the droplet frequency is in the range of 10 to 100 kHz. For example, by setting the drive voltage to 8.0 to 9.5 volts, the print speed to 300 feet per minute, the pulse heating temperature to 25 to 45° C., and the pulse length to 0.7-2.5 microseconds, high-quality printing can be obtained, although values ​​higher or lower than these descriptions can also be used and still obtain satisfactory printing. A non-limiting printhead example suitable for the disclosed method is the FUNAI TIJ ink cartridge manufactured by Funai Co.

[0186] After application, the inkjet ink is dried. In some embodiments, external heating can be applied to dry the applied inkjet ink, for example by using a heater. However, it is preferred that no external heat is applied to promote drying or increase the drying speed. Therefore, in a preferred embodiment, drying is achieved by allowing the applied inkjet ink to dry under ambient conditions (in air at about 23°C) for 30 seconds or less, preferably 25 seconds or less, more preferably 20 seconds or less, even more preferably 15 seconds or less, and still more preferably 10 seconds or less, without using an external heat source such as a heater. In addition, the method of the present disclosure does not require energy curing (e.g., UV or electron beam curing). Once the applied ink is deemed dry, further inkjet ink coatings can be applied, or any processing steps known to those of ordinary skill in the art can be performed as needed.

[0187] It should also be appreciated that substrate surface treatments, such as corona treatment, room temperature plasma treatment, and flame treatment, can optionally be employed in the methods herein prior to application of the inkjet ink to improve printed article properties, such as ink adhesion. The parameters of such substrate surface treatments can vary widely depending on the substrate to be printed, the specific inkjet ink used, the printing method employed, and the desired properties and application of the printed article.

[0188] The following experimental examples are intended to further illustrate the inkjet ink and are not intended to limit the scope of the claims.

[0189] Experimental example

[0190] Material

[0191] EB acetate is ethylene glycol mono-n-butyl ether acetate (bp 192°C) available from Eastman. PICCOLYTE A 25 is a terpene resin made from α-pinene (ring and ball SP = 22-28°C) available from Pinova. DERTOPHENET 160 is a terpene phenolic resin (OHV = 60 mgKOH / g; SP = 160°C; Mw = approximately 1000 g / mol) available from DRT / Pinova. BYK-307 is a polyether-modified polydimethylsiloxane surfactant available from BYK Additives & Instruments. OIL BLACK 860 is an organic dye available from Orient Chemical Industries.

[0192] Inkjet ink evaluation method

[0193] Print sample preparation

[0194] Inkjet ink experiments were conducted using FUNAI TIJ ink cartridges manufactured by Funai Co. The inks were evaluated using thermal printing technology associated with FUNAI (software and hardware manufactured by XiJet, transport platform manufactured by Kirk Rudy).

[0195] Optical density evaluation

[0196] To evaluate the optical density, the printing conditions used were as follows:

[0197] - Print substrate: White area on Form 2C opaque chart, an opaque chart with a black and white seal, measuring 7-5 / 8 x 10-1 / 4 inches (194 x 260 mm), available from Leneta Company, Inc.

[0198] -Print resolution: 300dpi*300dpi (vertical*horizontal)

[0199] -Pre-fire: 500nsec

[0200] - Dead time 1700nsec

[0201] -Main Fire: 1400nsec

[0202] - Voltage 9.0V

[0203] - Pulse heating off

[0204] -Print image; 100% duty cycle (1cm*10cm, monochrome bitmap, solid block image)

[0205] A solid block print image was printed, and the optical density of the image was measured using an X-rite eXact, density / TVI mode spectrophotometer sold by X-rite.

[0206] Kaifeng time evaluation

[0207] To evaluate the opening time, the printing conditions used were as follows:

[0208] -Printing substrate: plain (uncoated) paper

[0209] -Print resolution: 300dpi*300dpi (vertical*horizontal)

[0210] -Pre-fire: 500nsec

[0211] - Dead time 1700nsec

[0212] -Main transmit 1400nsec

[0213] - Voltage 9.0V

[0214] - Pulse heating off

[0215] - Print image: 100% duty cycle (1mm*1cm, monochrome bitmap, fine line image) (see Figure 2 )

[0216] A fine line image is printed to confirm that there are no missing or unclear lines in the printed image (indicating clogged or missing nozzles). After confirmation, the print head is unsealed for a specific period of time (30 seconds, 1 minute, 10 minutes, or 60 minutes) and then reprinted using the same fine line image. The reprinted fine line image is inspected (after the specific period of time) to determine if line loss / loss of line sharpness has occurred. If no line loss / loss of line sharpness occurs, the inkjet ink is given a "good" unsealing rating for that time interval. If there is 1-2 line loss / loss of sharpness during the tested time interval, but it is not enough to significantly affect the sharpness or readability of the fine line image during the tested time interval, the inkjet ink is given an "acceptable" unsealing rating for that time interval. If there is more than 2 line loss / loss of sharpness during the tested time interval, the inkjet ink is classified as "poor" for that time interval. A suitable / ideal inkjet ink is one that achieves an "acceptable" or "good" unsealing classification when unsealed (i.e., exposed to air) during each tested time interval.

[0217] Spray distance evaluation

[0218] To evaluate the jetting distance, the printing conditions used were as follows:

[0219] -Printing substrate: plain (uncoated) paper

[0220] -Print resolution: 300dpi*300dpi (vertical*horizontal)

[0221] - Pre-transmission 500nsec

[0222] - Dead time 1700nsec

[0223] -Main transmit 1400nsec

[0224] - Voltage 9.0V

[0225] - Pulse heating off

[0226] -Test distance between print head and substrate (jet distance): 2mm, 4mm, 6mm, 8mm, 10mm

[0227] - Print image: 100% duty cycle (see Figure 1 )

[0228] ○ An alphanumeric sequence that reads as follows:

[0229] Kao Collins Inc.

[0230] 1201 Edison Drive,

[0231] Cincinnati, OH 45216

[0232] Alphanumeric sequences were printed onto substrates at various test jet distances, and the resulting printed images were visually assessed for image quality at the test jet distances and rated according to Table 1. Suitable / ideal inkjet inks are those that achieve a "good" or "acceptable" jet distance rating at a jet distance of at least 8 mm.

[0233] Table 1. Spray distance evaluation

[0234]

[0235] Inkjet ink experimental example

[0236] The experimental example inkjet inks are given in Table 2. The amount of each component is expressed as weight percent relative to the total weight of the inkjet ink (100%).

[0237] *Indicates that this experimental example is a comparative experimental example.

[0238] Preparation method

[0239] To prepare the experimental inks, the resin and any surfactants were first mixed with the aforementioned combination of methyl ethyl ketone (MEK), dioxolane, and 1-propanol and mixed for at least 30 minutes using a mechanical stirrer. EB acetate was then added to the mixture and mixed for at least 15 minutes. The dye was then added to the mixture and mixed for at least 30 minutes to produce the inkjet ink. The inkjet inks were then evaluated using a FUNAI TIJ ink cartridge manufactured by Funai Co.

[0240] Table 2. Inkjet Ink Experimental Examples 1-9

[0241]

[0242] *Indicates that this experimental example is a comparative experimental example

[0243] Inkjet ink properties

[0244] As can be seen from Table 3, the combination of methyl ethyl ketone, dioxolane, and terpene resin provides significant results in terms of jetting distance and decapping time (Experimental Examples 1-5, 8, and 9). In contrast, the inkjet ink formulated without dioxolane performs poorly in terms of jetting distance, achieving readable images only at short jetting distances of 2 to 4 mm and yielding unacceptable image quality in the 6-10 mm range (Experimental Example 6).

[0245] With respect to the amount of dioxolane, it was found that loadings in the range of 20.90-81.00 wt.% provided long jetting distances and excellent decapping behavior (Experiments 1-4, 8, and 9). Reducing the amount of dioxolane to 5.90 wt.% maintained good decapping behavior and resulted in a slight decrease in jetting distance capability (Experimental Example 5, 8 mm jetting distance), which was nevertheless still far superior to inkjet inks lacking dioxolane.

[0246] It was also found that not all resins are compatible with the MEK / dioxolane solvent system, and those inkjet inks formulated with terpene-phenolic resins but without terpene resins exhibited poor de-seal behavior at every de-seal interval tested (Experimental Example 7). Furthermore, inks formulated without surfactants (Experimental Example 8) or without terpene-phenolic resins (Experimental Example 9) maintained ideal de-seal and jetting distance performance.

[0247] Table 3. Evaluation of Inkjet Ink Experimental Examples 1-9

[0248]

[0249] Where numerical limitations or ranges are stated herein, the endpoints are included. Furthermore, all values ​​and sub-ranges within the numerical limitations or ranges are expressly included as if expressly written.

[0250] As used herein, the words "a," "an," and the like have the meaning of "one or more."

[0251] Whether explicitly stated or not, the present disclosure also contemplates other embodiments that "comprise," "consist of," and "consist essentially of" the embodiments or elements presented herein.

[0252] Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the present invention may be practiced otherwise than as specifically described herein.

[0253] All patent and other references mentioned above are incorporated herein by reference in their entirety as if fully set forth.

Claims

1. An inkjet ink, wherein: Include: (A1) terpene resins; and (B) a solvent system comprising (B1) a ketone solvent having a boiling point lower than 120° C., and (B2) dioxolane, The terpene resin (A1) refers to an oligomer or polymer having 100 wt.% of a constituent unit derived from polymerizable terpene based on the total constituent units. The terpene resin (A1) is present in an amount of 0.1-10 wt.%, based on the total weight of the inkjet ink, The ketone solvent (B1) is present in an amount of 1-90 wt.%, based on the total weight of the inkjet ink, The dioxolane (B2) is present in an amount of 2-90 wt. %, based on the total weight of the inkjet ink.

2. The inkjet ink according to claim 1, wherein The terpene resin (A1) is present in an amount of 1-2 wt.%, based on the total weight of the inkjet ink.

3. The inkjet ink according to claim 1 or 2, wherein The terpene resin (A1) is a homopolymer made from α-pinene.

4. The inkjet ink according to claim 1 or 2, wherein The number average molecular weight M of the terpene resin (A1) n is at least 330 g / mol and at most 1500 g / mol.

5. The inkjet ink according to claim 1 or 2, wherein The softening point of the terpene resin (A1) is at least 20°C and at most 160°C.

6. The inkjet ink according to claim 1 or 2, wherein The bromine value of the terpene resin (A1) is at least 12 and at most 35.

7. The inkjet ink according to claim 1 or 2, wherein The ketone solvent (B1) is present in an amount of 3-85 wt. %, based on the total weight of the inkjet ink.

8. The inkjet ink according to claim 1 or 2, wherein The ketone solvent (B1) is methyl ethyl ketone.

9. The inkjet ink according to claim 1 or 2, wherein The dioxolane (B2) is present in an amount of 5-85 wt. %, based on the total weight of the inkjet ink.

10. The inkjet ink according to claim 1 or 2, wherein The weight ratio of the dioxolane (B2) to the ketone solvent (B1) (B2): (B1) is 0.05:1-30:

1.

11. The inkjet ink according to claim 1 or 2, wherein The weight ratio of the dioxolane (B2) to the terpene resin (A1) is (B2): (A1) 5:1-100:

1.

12. The inkjet ink according to claim 1 or 2, wherein The solvent system (B) further comprises (B3) a glycol ether.

13. The inkjet ink according to claim 12, wherein The glycol ether (B3) is a monoalkyl monoester ether.

14. The inkjet ink according to claim 12, wherein The glycol ether (B3) is present in an amount of 0.1-20 wt. %, based on the total weight of the inkjet ink.

15. The inkjet ink according to claim 12, wherein The weight ratio of the ketone solvent (B1) to the glycol ether (B3) is at least 1:1 and at most 50:

1.

16. The inkjet ink according to claim 1 or 2, wherein The solvent system (B) further comprises (B4) an alcohol solvent.

17. The inkjet ink according to claim 16, wherein The alcohol solvent (B4) is present in an amount of 0.1-20 wt. %, based on the total weight of the inkjet ink.

18. The inkjet ink according to claim 16, wherein The weight ratio of the terpene resin (A1) to the alcohol solvent (B4) (A1):(B4) is at least 1:5 and at most 5:

1.

19. The inkjet ink according to claim 1 or 2, wherein Does not contain solvents with a boiling point higher than 220°C.

20. The inkjet ink according to claim 1 or 2, wherein Also included is (A2) a terpene phenol resin.

21. The inkjet ink according to claim 20, wherein The weight average molecular weight Mw of the terpene phenol resin (A2) is at least 400 g / mol and at most 3000 g / mol.

22. The inkjet ink according to claim 20, wherein The softening point of the terpene phenol resin (A2) is at least 60°C and at most 160°C.

23. The inkjet ink according to claim 20, wherein The terpene phenol resin (A2) has a hydroxyl value of 10 mgKOH / g to 150 mgKOH / g.

24. The inkjet ink according to claim 20, wherein The terpene phenol resin (A2) is present in an amount of 0.1-10 wt. %, based on the total weight of the inkjet ink.

25. The inkjet ink according to claim 1 or 2, wherein It also contains (C) a surfactant.

26. The inkjet ink according to claim 25, wherein The surfactant (C) is present in an amount of 0.001-4 wt.%, based on the total weight of the inkjet ink.

27. The inkjet ink according to claim 25, wherein The surfactant (C) is polyether-modified silicone.

28. The inkjet ink according to claim 1 or 2, wherein Also contains (D) a colorant.

29. A printed product, wherein include: A substrate and a dry form of the inkjet ink of any one of claims 1 to 28 disposed on the substrate.

30. A method of forming a printed image on a substrate, in, include: spraying the inkjet ink according to any one of claims 1 to 28 onto the substrate using a thermal inkjet print head; and The inkjet ink is dried.

Images