Invisible fluorescent solvent-based inkjet ink composition

Abstract

Invisible fluorescent solvent inkjet ink compositions comprising a fluorescent colorant comprising a coumarin, a solvent, a binder resin, and a conductive agent are described.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 504,592, filed May 26, 2023. The entire contents of each of the preceding applications listed above are incorporated herein by reference. Technical Field

[0003] This technology generally relates to ink compositions for printers, and more particularly to invisible fluorescent solvent inkjet ink compositions comprising a fluorescent colorant containing coumarin, a solvent, a binder resin, and a conductive agent. Background Technology

[0004] Fluorescent inks are widely used in applications where occult (invisible) or visible features need to be read visually or by sensors. Invisible fluorescent dyes are used in invisible fluorescent inks that are visible under ultraviolet light excitation. Common invisible fluorescent dyes include violet derivatives, such as 4,4'-bis(2-benzoxazolyl)violet and 4,4'-diamino-2,2'-violet disulfonic acid; biphenyl derivatives, such as 4,4'-diamino[1,1'-biphenyl]-2,2'-disulfonic acid and benzidine-3-sulfonic acid; pyrazoline derivatives, such as 1,3-diphenyl-5-(4-iodophenyl)-2-pyrazoline; bis(benzoxazol-2-yl) derivatives, such as 2,5-bis(5-tert-butyl-benzoxazol-2-yl)thiophene; and coumarin derivatives, such as 7-amino-4-methylcoumarin and 7-hydroxycoumarin.

[0005] Formulating fluorescent inks for inkjet applications presents several challenges. For example, commercially available fluorescent inks perform well in many scenarios where printed codes are invisible to the naked eye but emit visible light under ultraviolet excitation. However, these commercially available fluorescent inks have limited solubility in common inkjet ink solvents such as methyl ethyl ketone (MEK) and ethanol. Due to this limited solubility, the amount of dye used in MEK-based inks is limited to approximately 0.2% to approximately 0.5% of the composition weight. When the dye amount exceeds approximately 0.2% of the composition weight, the reliability of printer uptime is significantly and adversely affected.

[0006] To optimize printer reliability and fluorescence intensity, the amount of fluorescent dye in commercially available inks is about 0.2% by weight of the composition. Due to this practical limitation on the amount of fluorescent dye, the fluorescence intensity of commercially available inks is sometimes insufficient for a sensor to detect the print code, especially on high speed production lines where the size of the printed image must be reduced to achieve the required speed. This results in less fluorescence being detectable by the sensor, while the detection time of the sensor is also shorter due to the higher speed. Increasing the amount of dye in commercially available inks increases the fluorescence intensity of the ink; however, this is at the expense of printer reliability. Therefore, there is a current need to develop an invisible fluorescent solvent-based inkjet ink composition having higher fluorescence intensity, while optimizing printer reliability, and acceptable printing speed.

[0007] The present invention addresses these needs by providing an invisible fluorescent solvent-based inkjet ink composition comprising a fluorescent colorant comprising coumarin, a solvent, a binding resin, and a conductive agent. SUMMARY

[0008] In one aspect, the present invention provides an inkjet ink composition comprising:

[0009] a fluorescent colorant comprising coumarin,

[0010] a solvent,

[0011] a binding resin, and

[0012] a conductive agent.

[0013] In one embodiment, the coumarin comprises 7-hydroxycoumarin or 7-(substituted amino)coumarin. In one embodiment, the coumarin comprises 7-diethylamino-4-methylcoumarin. In one embodiment, the coumarin does not comprise 3-phenyl-7-(l,2H-naphthotriazolyl)-coumarin, and / or the fluorescent colorant does not comprise 3-phenyl-7-(l,2H-naphthotriazolyl)-coumarin.

[0014] In one embodiment, the fluorescent colorant has one or more of the following properties:

[0015] (a) a maximum absorption wavelength of about 330 nanometers to about 400 nanometers, preferably about 345 nanometers to about 385 nanometers; and

[0016] (b) a peak emission wavelength of about 400 nanometers to about 600 nanometers, preferably about 430 nanometers to about 530 nanometers.

[0017] In one embodiment, the fluorescent colorant is present in an amount of about 0.3% to about 5% by weight of the composition, preferably in an amount of about 0.6% to about 3% by weight of the composition.

[0018] In one embodiment, the solvent comprises one or more of ketones, esters, alcohols, lactate esters, glycols, glycol ethers, glycol ether acetates, and glycol ether esters. In one embodiment, the solvent comprises one or more of methyl ethyl ketone, methyl propyl ketone, diethyl ketone, methyl isopropyl ketone, cyclohexanone, cyclopentanone, acetone, ethanol, n-propanol, isopropanol, n-butanol, methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, ethyl lactate, butyl lactate, propylene glycol, and propylene glycol methyl ether acetate.

[0019] In one embodiment, the solvent is present in an amount of at least about 50% by weight of the composition. In one embodiment, the solvent is present in an amount of from about 50% to about 90% or from about 75% to about 85% by weight of the composition.

[0020] In one embodiment, the bonding resin comprises one or more of acrylic resins, styrene acrylic resins, copolymers of styrene and allyl alcohol, ketone resins, aldehyde resins, polyketone resins, natural resins or modified natural resins (such as rosin esters and terpene modified resins), sulfonamide resins, sulfonamide-formaldehyde resins, toluenesulfonamide resins, bisphenol A toluenesulfonamide resins, cellulose esters (such as cellulose acetate butyrate and cellulose acetate propionate), cellulose ethers (such as ethyl cellulose), polyvinyl butyral, polyurethanes, phenolic resins, modified phenolic resins, polyamide resins, vinyl resins (e.g., copolymers of vinyl chloride and vinyl acetate, with or without a third monomer), polyvinyl alcohol, polyvinyl acetate, nitrocellulose resins, polyester resins, and any combination thereof; preferably, the one or more resins are acrylic resins, styrene acrylic resins, copolymers of styrene and allyl alcohol, ketone resins, aldehyde resins, polyketone resins, natural resins or modified natural resins (such as rosin esters and terpene resins), sulfonamide resins, sulfonamide-formaldehyde resins, toluenesulfonamide resins, bisphenol A toluenesulfonamide resins, cellulose ethers (such as ethyl cellulose), cellulose esters (such as cellulose acetate butyrate and cellulose acetate propionate), cellulose ethers (such as ethyl cellulose), polyvinyl butyral, and any combination thereof.

[0021] In one embodiment, the bonding resin does not comprise nitrocellulose. In one embodiment, the bonding resin comprises one or more bonding resins having a weight average molecular weight of less than about 50,000 Daltons, preferably, less than about 30,000 Daltons, more preferably, less than about 15,000 Daltons. In one embodiment, the bonding resin is present in an amount of from about 10% to about 30%, preferably, from about 15% to about 25% by weight of the composition.

[0022] In one embodiment, the conductive agent comprises one or more of an organoammonium salt, an organobromine salt, an organophosphorus salt, an organoborate, and an organophosphate. In one embodiment, the conductive agent comprises one or more tetraalkylammonium salts. In one embodiment, the conductive agent comprises one or more of tetrabutylammonium hexafluorophosphate, tetrapropylammonium hexafluorophosphate, tetraethylammonium hexafluorophosphate, tetramethylammonium hexafluorophosphate, tetrabutylammonium tetraphenylborate, tetrabutylammonium tetrabutylborate, tetramethylammonium bromide, tetraethylammonium bromide, tetrabutylammonium bromide, tetrapropylammonium bromide, and tetrabutylammonium nitrate.

[0023] In one embodiment, the conductive agent is present in an amount of about 0.5% to about 5% by weight of the composition, preferably about 1% to about 3%.

[0024] In one embodiment, the composition described herein may further comprise one or more of a humectant, a cosolvent, a resin co-reagent, a defoamer, a thickener, a plasticizer, a dispersant, a surfactant, and a corrosion inhibitor.

[0025] In one embodiment, the composition has a viscosity of about 2 to about 6 centipoise at about 25°C, preferably about 3 to about 5 centipoise at about 25°C. In one embodiment, the resistivity of the composition at about 25°C is in the range of about 1000 to about 2000 ohm-cm. Detailed Implementation

[0026] Various embodiments will be described below. It should be noted that the specific embodiments are not intended as an exhaustive description or as a limitation on the broader aspects discussed herein. One aspect described in connection with a particular embodiment is not necessarily limited to that embodiment and may be implemented in conjunction with any other embodiment.

[0027] As used herein, the term “approximately” has the meaning understood by one of ordinary skill in the art, and its meaning may vary depending on the context of use. If one of ordinary skill in the art is unclear about the usage of the term based on the context, “approximately” means plus or minus 10% of that particular item.

[0028] In describing elements (particularly in the context of the following claims), the terms “an,” “a,” and “the,” and similar pronouns, should be interpreted to cover both singular and plural forms, unless otherwise stated herein or clearly contradicted by the context. The enumeration of numerical ranges herein is intended only as a simplified method of individually referring to each individual value falling within that range, unless otherwise stated herein, and each individual value is incorporated into the specification as if individually enumerated herein. All methods described herein may be performed in any suitable order, unless otherwise stated herein or clearly contradicted by the context. Any and all example or exemplary language used herein (e.g., “such as”) is intended only to better illustrate embodiments and does not constitute a limitation on the scope of the claims, unless otherwise stated. No language in the specification should be construed as indicating that any unclaimed element is necessary.

[0029] This article describes an invisible fluorescent solvent-based inkjet ink composition comprising a coumarin-containing fluorescent colorant, a solvent, a binder resin, and a conductive agent. The compositions described herein exhibit excellent solubility in inkjet solvents such as methyl ethyl ketone and ethanol, allowing for the addition of more dye to the composition, thereby increasing fluorescence intensity. Furthermore, the compositions described herein also demonstrate excellent printer reliability. Compared to commercially available invisible fluorescent inks, the compositions described herein represent a significant improvement—commercially available invisible fluorescent inks have limited solubility in typical ink solvents and exhibit lower fluorescence intensity.

[0030] This invention discovers that coumarin dyes (such as 7-diethylamino-4-methylcoumarin) exhibit excellent solubility in both methyl ethyl ketone and ethanol, and that fluorescence intensity increases with increasing dye concentration until a critical point is reached where optimal levels are achieved in inkjet ink compositions. After this point, the fluorescence intensity of the dry ink decreases with further increases in dye concentration. Without being bound by theory, it is hypothesized that as dye concentration increases, the dye molecules begin to self-quench as they become too close together. Furthermore, this invention also discovers that higher levels of optimal ink fluorescence intensity can be achieved by increasing the total solids content, for example, by using any of the resins described herein. Again, without being bound by theory, it is hypothesized that increasing the total solids content causes the dye molecules to be further apart, thus increasing the dye concentration at which self-quenching begins in the dry ink.

[0031] As illustrated in the examples, the invisible fluorescent solvent-based inkjet ink compositions formulated according to the present invention (e.g., those using coumarin dyes and one or more binder resins described herein) are compositions with higher dye concentrations and higher total solids content than conventional invisible fluorescent solvent-based inkjet ink compositions. Furthermore, the fluorescence intensity of the invisible fluorescent solvent-based inkjet ink compositions described herein is up to 3 times higher than that of comparative ink formulations (e.g., dye A, a commercially available fluorescent ink comprising 5-bis(5-tert-butyl-benzoxazol-2-yl)thiophene, also known as 2,5-bis(5-tert-butyl-benzoxazol-2-yl)thiophene). In one embodiment, the fluorescence intensity of the inkjet ink composition is 1, 2, or 3 times higher than that of the comparative ink formulation.

[0032] One aspect of the present invention provides an inkjet ink composition comprising:

[0033] Fluorescent colorants containing coumarin,

[0034] Solvent,

[0035] Adhesive resin, and

[0036] Conductive agent.

[0037] Fluorescent colorant

[0038] The inkjet ink compositions described herein contain fluorescent colorants. As described herein, the fluorescent colorants contain one or more coumarin dyes.

[0039] Suitable examples of coumarin dyes include dyes comprising 7-hydroxycoumarin or 7-(substituted amino)coumarin. Other suitable examples of coumarin fluorescent dyes include 7-diethylamino-4-methylcoumarin, 7-(diethylamino)coumarin-3-carboxylic acid, 7-amino-4-methylcoumarin, 7-amino-3-phenylcoumarin, 7-hydroxycoumarin, 7-hydroxycoumarin-3-carboxylic acid, 6,8-difluoro-7-hydroxy-4-methylcoumarin, 6,7-bis(acetoxy)coumarin, 3-(3-phenyl-2-oxazolyl)-7-(diethylamino)coumarin, 3-(4-phenyl-2-oxazolyl)-7-(diethylamino)coumarin, and 3-(2-benzothiazolyl)-7-(diethylamino)coumarin. In one embodiment, the coumarin comprises 7-diethylamino-4-methylcoumarin (e.g., fluorescent whitening agent 140).

[0040] In one embodiment, the fluorescent colorant (e.g., the coumarin dye) does not contain 3-phenyl-7-(1,2H-naphthotriazolyl)-coumarin.

[0041] Suitable fluorescent colorants include those that have a solubility of more than about 1%, more preferably more than about 2%, in the ink solvent or solvent mixture over the temperature range the ink may be exposed to (e.g., about -15°C to about 60°C). The solubility of fluorescent dyes in solvents typically decreases with decreasing temperature, making it more challenging to achieve printer reliability in cold environments, as dye sedimentation can lead to nozzle clogging and jetting deviations. In hot environments, while solubility issues are less pronounced, similar problems arise because the dye concentration at the nozzle rises rapidly due to the high volatility of the solvent near the nozzle.

[0042] In one embodiment, the fluorescent colorant has one or more of the following characteristics: (a) a maximum absorption wavelength of about 330 nm to about 400 nm, preferably about 345 nm to about 385 nm; and (b) a peak emission wavelength of about 400 nm to about 600 nm, preferably about 430 nm to about 530 nm.

[0043] In one embodiment, the fluorescent colorant has a maximum absorption wavelength of about 330 nm to about 400 nm, including about 330 nm, about 335 nm, about 340 nm, about 345 nm, about 350 nm, about 355 nm, about 360 nm, about 365 nm, about 370 nm, about 375 nm, about 380 nm, about 385 nm, about 390 nm, about 395 nm, and about 400 nm. In one embodiment, the fluorescent colorant has a maximum absorption wavelength of about 345 nm to about 385 nm.

[0044] In one embodiment, the fluorescent colorant has a peak emission wavelength of about 400 nm to about 600 nm, including about 400 nm, about 405 nm, about 410 nm, about 415 nm, about 420 nm, about 425 nm, about 430 nm, about 435 nm, about 440 nm, about 445 nm, about 450 nm, about 455 nm, about 460 nm, about 465 nm, about 470 nm, about 475 nm, about 480 nm, and about 485 nm. Nanometers, approximately 490 nanometers, approximately 495 nanometers, approximately 500 nanometers, approximately 505 nanometers, approximately 510 nanometers, approximately 515 nanometers, approximately 520 nanometers, approximately 525 nanometers, approximately 530 nanometers, approximately 535 nanometers, approximately 540 nanometers, approximately 545 nanometers, approximately 550 nanometers, approximately 555 nanometers, approximately 560 nanometers, approximately 565 nanometers, approximately 570 nanometers, approximately 575 nanometers, approximately 580 nanometers, approximately 585 nanometers, approximately 590 nanometers, approximately 595 nanometers, and approximately 600 nanometers. In one embodiment, the fluorescent colorant has a peak emission wavelength of approximately 430 nanometers to approximately 530 nanometers.

[0045] In one embodiment, the fluorescent colorant is present in an amount of about 0.3% to about 5% by weight of the composition, including about 0.3%, about 0.4%, about 0.5%, about 0.6%, about 0.7%, about 0.8%, about 0.9%, about 1%, about 1.5%, about 2%, about 2.5%, about 3%, about 3.5%, about 4%, about 4.5%, and about 5%. In another embodiment, the fluorescent colorant is present in an amount of about 0.6% to about 3% by weight of the composition.

[0046] solvent

[0047] The inkjet ink compositions described herein contain solvents. Suitable examples include, but are not limited to, one or more of ketones, esters, alcohols, lactates, glycols, glycol ethers, glycol ether acetates, and glycol ether esters. Suitable examples of ketones include, but are not limited to, acetone, methyl ethyl ketone, 3-methyl-2-butanone (methyl isopropyl ketone), 2-pentanone (methyl propyl ketone), diethyl ketone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone. Suitable examples of esters include, but are not limited to, methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, tert-butyl acetate, amyl acetate, methyl lactate, ethyl lactate, n-propyl lactate, isopropyl lactate, n-butyl lactate, and methoxypropyl acetate. Suitable examples of alcohols include, but are not limited to, methanol, ethanol, n-propanol, isopropanol, n-butanol, tert-butanol, n-pentanol, and n-hexanol. Suitable examples of glycols include, but are not limited to, ethylene glycol, propylene glycol, glycerol, and diethylene glycol. Suitable examples of glycol ethers or glycol ether acetates include, but are not limited to, methoxypropanol, dipropylene glycol methyl ether, propylene glycol propyl ether, propylene glycol butyl ether, tripropylene glycol methyl ether, butanediol methyl ether, dibutyl methyl ether, dipropylene glycol methyl ether acetate, propylene glycol propyl ether acetate, and propylene glycol butyl ether acetate.

[0048] In one embodiment, the solvent comprises one or more of ketones, esters, alcohols, lactate esters, glycols, glycol ethers, glycol ether acetates, glycol ether acetates, and glycol ether esters. In one embodiment, the solvent comprises one or more of methyl ethyl ketone, methyl propyl ketone, diethyl ketone, methyl isopropyl ketone, cyclohexanone, cyclopentanone, acetone, ethanol, n-propanol, isopropanol, n-butanol, methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, ethyl lactate, butyl lactate, propylene glycol, and propylene glycol methyl ether acetate.

[0049] In one embodiment, the solvent is present in an amount of at least about 50% of the composition weight, including at least about 55%, at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, and at least about 90%. In one embodiment, the solvent is present in an amount of about 50% to about 90% of the composition weight, including about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, and about 90%. In one embodiment, the solvent is present in an amount of about 75% to about 85% of the composition weight.

[0050] Adhesive resin

[0051] The inkjet ink compositions described herein include a binder resin. The binder resin provides adhesion of the ink to a substrate, thereby preventing the printed markings from being damaged or detached from the marking surface during post-marking product processing. These binder resins can be used in conjunction with co-resins. Suitable examples of binder resins include any resin that is soluble in or dispersible in the solvents described herein. Other suitable examples of binder resins include acrylic resins, styrene-acrylic resins, copolymers of styrene and allyl alcohol, ketone resins, aldehyde resins, polyketone resins, natural resins or modified natural resins (such as rosin esters and terpene-modified resins), sulfonamide resins, sulfonamide-formaldehyde resins, toluenesulfonamide resins, bisphenol A toluenesulfonamide resins, cellulose esters (such as cellulose acetate butyrate and cellulose acetate propionate), cellulose ethers (such as ethyl cellulose), polyvinyl butyral, polyurethane, phenolic resins, modified phenolic resins, polyamide resins, and vinyl resins (e.g., copolymers of vinyl chloride and polyvinyl acetate, with or without a third monomer). One or more of polyvinyl alcohol, polyvinyl acetate, nitrocellulose resin, polyester resin, and any combination thereof, preferably one or more of acrylic resin, styrene acrylic resin, copolymer of styrene and allyl alcohol, ketone resin, aldehyde resin, polyketone resin, natural resin or modified natural resin (such as rosin ester and terpene resin), sulfonamide resin, sulfonamide-formaldehyde resin, toluenesulfonamide resin, bisphenol A toluenesulfonamide resin, cellulose ether (such as ethyl cellulose), cellulose ester (such as cellulose acetate butyrate and cellulose acetate propionate), cellulose ether (such as ethyl cellulose), polyvinyl butyral, and any combination thereof.

[0052] Acrylic resins can be homopolymers or copolymers containing two or more monomers, with or without specific functional groups. Functionalized acrylic resins can be derived from alkyl monomers (such as methacrylates) plus functionalized monomers (such as acrylic acid or methacrylic acid), basic monomers such as aminoacrylates, or neutral functionalized monomers containing hydroxyl groups. Suitable examples of resins include resins sold by Dow Chemical Corporation under the trade names ACRYLOID or PARALOID, or DIANAL resins from Dianal Corporation (e.g., DIANALPB-204). A specific example of a non-functionalized resin is a resin sold under the trade name PARALOID B-60, which is a copolymer of methyl methacrylate and butyl methacrylate with a molecular weight of approximately 50,000 Daltons. Other examples include those from Lubrizol. 525 and 527 resins, as well as those from Covestro Resins B-725, B-731, B-735, B-810, B-811, B-813, B-814, B-817, B-842, B-890, and B-891. Other suitable acrylic and styrene acrylic resins include those with a weight-average molecular weight of less than about 100,000. Other resins are those with side-attached amine groups, such as those disclosed in U.S. Patent No. 4,892,775.

[0053] Examples of acrylic resins also include styrene-acrylic resins, which can be obtained by copolymerizing styrene with acrylic monomers (such as acrylic acid or methacrylic acid), and optionally with alkyl acrylate monomers (such as methyl acrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, etc.), produced by BASF under the trade name... Production. Examples of resins include 500, 586, 611, 678, 680, 682, 683, 690, 693 and 67.

[0054] Suitable resins containing vinyl acetate / vinyl chloride copolymers are those marketed by Wacker Chemie AG under the trade name VINNOL. These resins include structurally modified carboxyl-vinyl chloride / vinyl acetate polymers (e.g., E15 / 45M), hydroxyl-modified vinyl chloride / vinyl acetate polymers (e.g., E15 / 40A) and unmodified vinyl chloride / vinyl acetate polymers (e.g., (H14 / 36). As long as they are soluble in the carrier, vinyl acetate / vinyl chloride copolymers with any structural modification or any vinyl chloride:vinyl acetate ratio can be used.

[0055] An example of polyvinyl butyral resin comes from Wacker Chemie AG. BN 18, from Kuraray America, Inc. B20H, and S-LEC B polyvinyl butyral from Sekisui Products LLC. An example of ethyl cellulose resin is ETHOCEL from Dow Chemical. Another example of a cellulose-based resin is CAP-482-0.5 (cellulose acetate propionate) from Eastman Chemical.

[0056] Suitable polyurethane resins include those comprising flexible thermoplastic polyurethanes produced by the reaction of diols and diisocyanates. Examples of diols include ethylene glycol, propylene glycol, propylene glycol, butanediol, polyethylene glycol, polypropylene glycol, polyethylene glycol adipate, polyethylene glycol succinate, polytetrahydrofuran glycol, etc. Examples of diisocyanates include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, etc. Suitable polyurethane resins include those with a weight-average molecular weight in the range of about 4,000 to about 25,000. Specific examples of polyurethane resins include those marketed under the trade name BIP (Oldbury) Limited. The products sold. Various grades of polyurethane solutions sold under this name include... 2135 5299、 5244、 5255 2X, 5322 5311 and XL. 5322 is a polyurethane composed of polypropylene glycol and 4,4'-diphenylmethane diisocyanate, and is sold as a mixed solvent solution containing ethyl acetate and isopropanol.

[0057] Rosin ester resins include SUPERESTER 75 from Arakawa Chemical and [other resins] from Pinova Incorporated. Ester 10, the latter being a glycerol ester of partially hydrogenated wood rosin.

[0058] Other suitable resins include resins containing styrene-allyl copolymers (e.g., SAA 100) and resins containing cellulose acetate butyrate (e.g., CAB 551-0.01).

[0059] In one embodiment, the adhesive resin comprises one or more of the following: acrylic resin, styrene acrylic resin, copolymer of styrene and allyl alcohol, ketone resin, aldehyde resin, polyketone resin, natural resin or modified natural resin (such as rosin ester and terpene modified resin), sulfonamide resin, sulfonamide-formaldehyde resin, toluenesulfonamide resin, bisphenol A toluenesulfonamide resin, cellulose ester (such as cellulose acetate butyrate and cellulose acetate propionate), cellulose ether (such as ethyl cellulose), polyvinyl butyral, polyurethane, phenolic resin, modified phenolic resin, polyamide resin, vinyl resin (e.g., copolymer of vinyl chloride and vinyl acetate, with or without a third monomer), polyvinyl alcohol, polyvinyl acetate, nitrocellulose resin, polyester resin, and any combination thereof.

[0060] In one embodiment, the adhesive resin comprises one or more of the following: acrylic resin, styrene-acrylic resin, copolymer of styrene and allyl alcohol, ketone resin, aldehyde resin, polyketone resin, natural resin or modified natural resin (such as rosin ester and terpene resin), sulfonamide resin, sulfonamide-formaldehyde resin, toluenesulfonamide resin, bisphenol A toluenesulfonamide resin, cellulose ether (such as methylcellulose and ethylcellulose), cellulose ester (such as cellulose acetate butyrate and cellulose acetate propionate), cellulose ether (such as ethylcellulose), polyvinyl butyral, and any combination thereof.

[0061] In one embodiment, the bonding resin does not contain nitrocellulose.

[0062] Suitable resins include one or more adhesive resins with a weight-average molecular weight of less than about 50,000 Daltons, including less than about 45,000 Daltons, less than about 40,000 Daltons, less than about 35,000 Daltons, less than about 30,000 Daltons, less than about 25,000 Daltons, less than about 20,000 Daltons, and less than about 15,000 Daltons. In one embodiment, the adhesive resin comprises one or more adhesive resins with a weight-average molecular weight of less than about 50,000 Daltons. In one embodiment, the adhesive resin comprises one or more adhesive resins with a weight-average molecular weight of less than about 30,000 Daltons. In one embodiment, the adhesive resin comprises one or more adhesive resins with a weight-average molecular weight of less than about 15,000 Daltons. In one embodiment, the adhesive resin comprises one or more adhesive resins with a weight-average molecular weight from about 500 Daltons to about 50,000 Daltons.

[0063] In one embodiment, the adhesive resin is present in an amount of about 5% to about 35% by weight of the composition, including about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 11%, about 12%, about 13%, about 14%, about 15%, about 16%, about 17%, about 18%, about 19%, about 20%, about 21%, about 22%, about 23%, about 24%, about 25%, about 26%, about 27%, about 28%, about 29%, about 30%, about 31%, about 32%, about 33%, about 34%, and 35%. In one embodiment, the adhesive resin is present in an amount of about 15% to about 25% by weight of the composition.

[0064] conductive agent

[0065] The inkjet ink compositions described herein contain a conductive agent that can act as a charge carrier in the liquid ink to achieve the desired conductivity or resistivity. Suitable conductive agents include one or more of organoammonium salts, organobromine salts, organophosphorus salts, organoborates, and organophosphates. Another example of a suitable conductive agent includes one or more tetraalkylammonium salts. Other examples of suitable conductive agents include ammonium, alkali metal and alkaline earth metal salts, such as lithium nitrate, lithium thiocyanate, lithium trifluoromethanesulfonate, potassium bromide, etc.; amine salts, such as dimethylamine hydrochloride and hydroxylamine hydrochloride; and ammonium acetate.

[0066] Suitable examples of tetraalkylammonium salts include, but are not limited to, tetrabutylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium acetate, tetrabutylammonium nitrate, tetrabutylammonium hexafluorophosphate, tetrabutylammonium tetrafluoroborate, tetrabutylammonium thiocyanate, tetrapropylammonium chloride, tetrapropylammonium bromide, tetrapropylammonium acetate, tetrapropylammonium nitrate, tetrapropylammonium hexafluorophosphate, tetrapropylammonium tetrafluoroborate, tetrapropylammonium thiocyanate, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium acetate, tetraethylammonium nitrate, tetraethylammonium hexafluorophosphate, tetraethylammonium tetrafluoroborate, tetraethylammonium thiocyanate, tetramethylammonium chloride, tetramethylammonium bromide, tetramethylammonium acetate, tetramethylammonium nitrate, tetramethylammonium hexafluorophosphate, tetramethylammonium tetrafluoroborate, tetramethylammonium thiocyanate, tetrabutylphosphonium chloride, tetrabutylphosphonium bromide, and tetrabutylphosphonium acetate. Tetrabutylphosphonium nitrate, tetrabutylphosphonium hexafluorophosphate, tetrabutylphosphonium tetrafluoroborate, tetrabutylphosphonium thiocyanate, tetrapropylphosphonium chloride, tetrapropylphosphonium bromide, tetrapropylphosphonium acetate, tetrapropylphosphonium nitrate, tetrapropylphosphonium hexafluorophosphate, tetrapropylphosphonium tetrafluoroborate, tetrapropylphosphonium thiocyanate, tetraethylphosphonium chloride, tetraethylphosphonium bromide, tetraethylphosphonium acetate, tetraethylphosphonium nitrate, tetraethylphosphonium hexafluorophosphate, tetrafluoroborate The conductive agent comprises tetraethylphosphonium acetate, tetraethylphosphonium thiocyanate, tetramethylphosphonium chloride, tetramethylphosphonium bromide, tetramethylphosphonium acetate, tetramethylphosphonium nitrate, tetramethylphosphonium hexafluorophosphate, tetramethylphosphonium tetrafluoroborate, tetramethylphosphonium thiocyanate, tetraphenylphosphonium chloride, tetraphenylphosphonium bromide, tetraphenylphosphonium acetate, tetraphenylphosphonium nitrate, tetraphenylphosphonium hexafluorophosphate, tetraphenylphosphonium tetrafluoroborate, tetraphenylphosphonium thiocyanate, and ammonium acetate. In one embodiment, the conductive agent comprises a cation selected from tetraalkylammonium, tetraarylammonium, tetraalkylphosphonium, tetraarylphosphonium, and any combination thereof, and an anion selected from hexafluorophosphate, tetrafluoroborate, tetraalkylborate, tetraarylborate, and any combination thereof. Specific examples of conductive agents include, but are not limited to, tetrabutylammonium hexafluorophosphate, tetrapropylammonium hexafluorophosphate, tetraethylammonium hexafluorophosphate, tetramethylammonium hexafluorophosphate, tetrabutylammonium tetraphenylborate, tetrabutylammonium tetrabutylborate, tetrabutylammonium tetrafluoroborate, tetrapropylammonium tetrafluoroborate, tetraethylammonium tetrafluoroborate, tetramethylammonium tetrabromide, tetraethylammonium bromide, tetrabutylammonium bromide, tetrapropylammonium bromide, tetrabutylammonium nitrate, and any combination thereof.

[0067] In one embodiment, the conductive agent comprises one or more of tetrabutylammonium hexafluorophosphate, tetrapropylammonium hexafluorophosphate, tetraethylammonium hexafluorophosphate, tetramethylammonium hexafluorophosphate, tetrabutylammonium tetraphenylborate, and tetrabutylammonium tetrabutylborate. In one embodiment, the conductive agent comprises tetrabutylammonium bromide or tetrapropylammonium bromide.

[0068] In one embodiment, the conductive agent is present in an amount of about 0.5% to about 5% by weight of the composition, including about 0.5%, about 1%, about 1.5%, about 2%, about 2.5%, about 3%, about 3.5%, about 4%, about 4.5%, and about 5%. In one embodiment, the conductive agent is present in an amount of about 1% to about 3% by weight of the composition.

[0069] Other components

[0070] In one embodiment, any inkjet ink composition described herein further comprises one or more of a humectant, a cosolvent, a resin, a defoamer, a tackifier, a plasticizer, a dispersant, a surfactant, and a corrosion inhibitor.

[0071] Humectants are used to prevent ink from drying out on the printhead during printing operations and during ink storage. Humectants are typically hydrophilic solvents with high boiling points (e.g., above 100°C or from about 150°C to about 250°C). Suitable humectants include, but are not limited to, diacetone alcohol, lactates (such as ethyl lactate and butyl lactate), glycols (such as ethylene glycol, propylene glycol, glycerol, diglycerol, and diethylene glycol); glycol ethers (such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol methyl ether, cellosolves, and diethylene glycol monoethyl ether). TM (e.g., diethylene glycol dimethyl ether and diethylene glycol diethyl ether); dialkyl sulfoxides (e.g., dimethyl sulfoxide); and other solvents (e.g., sulfolane and N-methylpyrrolidone). The humectant may be present in an amount of about 0.1% to about 10% by weight of the ink composition.

[0072] A co-solvent may be used in the inkjet ink compositions described herein. If a co-solvent is used, its amount is less than that of the main solvent, and it may be any of the solvents described herein. For example, the amount of the main solvent may be about two, three, four, five, or more times the amount of the co-solvent.

[0073] Co-resins can provide improved pigment dispersion and / or stability of ink compositions. An example of a co-resin is an aldehyde resin, such as urea-formaldehyde resin or ketone resin.

[0074] Defoamers are used to prevent ink foaming during ink preparation and printing operations. Suitable defoamers include polysiloxane defoamers, such as BYK, offered by BYK USA Inc. of Wallingford, Connecticut. TM 065. The defoamer may be present in any suitable amount, for example, in an amount of about 0.01% to about 1% of the weight of the ink composition.

[0075] The inkjet ink compositions described herein may contain tackifiers such as silanes or polyamines. Suitable tackifiers also include low molecular weight monomeric compounds, but dimers, trimers, or higher oligomers are also considered, containing one or more reactive groups, such as epoxy groups. Examples of suitable silanes include WETLINK 78 (γ-glycidoxypropyldiethoxymethylsilane), A-link 25 (3-isocyanate-propyltriethoxysilane), A-Link 35 (3-isocyanate-propyltrimethoxysilane), SilaneA-186 (3-(3,4-epoxycyclohexyl)ethyltrimethoxysilane), SilaneA-187 (γ-glycidoxypropyltrimethoxysilane) Silane A-1100 (γ-aminopropyltriethoxysilane) and COATOSIL TM 1770 (3-(3,4-epoxycyclohexyl)ethyltriethoxysilane), all of which are from Momentive. Other examples include ADDID 900 (amino-functionalized trimethoxysilane) and 940 (methacrylate trimethoxy-functionalized silane), both from Wacker Silicones Corp. Suitable polyamines include polyalkyleneamines (e.g., polyethyleneimine) and can be further modified by ethoxylation, epoxidation, or silanization. Other examples of polyamines include dendritic polymers and aminoacrylate polymers, such as those disclosed in U.S. Patents 5,596,027 and 6,221,933. Polyethyleneimine is commercially available and can be of any suitable molecular weight, for example, a weight-average molecular weight below about 10,000. The tackifier can be present in any suitable amount, for example, from about 0.01% to about 3% by weight.

[0076] Plasticizers can be used to further enhance the performance of printed information, such as durability. Suitable examples of plasticizers include phthalate plasticizers, such as alkyl benzyl phthalates, butyl benzyl phthalate, dioctyl phthalate, diisobutyl phthalate, dicyclohexyl phthalate, diethyl phthalate, dimethyl isophthalate, dibutyl phthalate, and dimethyl phthalate; esters, such as di(2-ethylhexyl) adipate, diisobutyl adipate, glyceryl tribenzoate, and sucrose benzoate. The ink composition contains esters such as dibutyl sebacate, dibutyl maleate, polypropylene glycol dibenzoate, neopentyl glycol dibenzoate, dibutyl sebacate, and tri-n-hexyl trimellitate; phosphate esters such as tricresyl phosphate, dibutyl phosphate, triethyl citrate, tributyl citrate, and tri-n-butyl acetylated citrate; polyurethanes; acrylic polymers; lactic acid esters; oxidized oils such as epoxidized soybean oil and oxidized linseed oil; and sulfonamide plasticizers, RIT-CIZER 8 (a mixture of N-ethyltoluenesulfonamides) from Rit-Chem Co. The plasticizers may be present in any suitable amount, for example, from about 0.01% to about 3% by weight of the ink composition.

[0077] Dispersants, such as polymeric dispersants, can be used to enhance pigment stability or reduce sedimentation rates. Hyperdispersants, which are polymeric dispersants containing groups that have an affinity for pigments, can also be used. An example of a hyperdispersant is SOLSPERSE from Lubrizol. TM 38500 (active polymer dispersant in propyl methacrylate). Suitable dispersants include those from BYKUSAInc. P104S. Other examples of superdispersants can be found in relevant literature, such as WO00 / 63305, the disclosure of which is incorporated herein by reference. Typically, suitable dispersants include those marketed under the trade name SOLSPERSE. TM Products sold by Lubrizol, EFKA (from BASF), and BYK or DISPERBYK (from BYK USA Inc.). The dispersant may be used in any suitable amount, for example, from about 0.1% to about 5% by weight of the ink composition.

[0078] Surfactants can be used to optimize the wetting and / or drying properties of inks. Suitable surfactants include siloxanes, silicones, silanols, polyoxyethylene amines, propoxylated (poly(oxypropylene))diamines, alkyl ether amines, nonylphenol ethoxylates, ethoxylated fatty amines, quaternized copolymers of vinylpyrrolidone and dimethylaminoethyl methacrylate, alkoxylated ethylenediamines, polyethylene oxides, polyoxyethylene polyalkylene polyamines, polyoxyethylene polyalkylene polyimides, mixtures of alkyl phosphate ethoxylates, polyoxyethylene derivatives of propylene glycol, polyoxyethylene fatty alcohols, and fluorinated surfactants. Examples of suitable polymeric silicone-based surfactants are marketed under the trade name SILWET. Examples of fluorinated surfactants include Chemours' product under the trade name ZONYL. Specific examples of suitable surfactants include... L-7622 (a polyoxyethylene-modified polydimethylsiloxane from Momentive) and FC 430 (a fluorinated aliphatic polymer ester from 3M). Another specific example of a surfactant is BYK-3550, which is an organosilicone surfactant. A specific example of a siloxane surfactant is ELEMENT14. TM PDMS 100. The surfactant may be present in the ink composition in any suitable amount, for example, in an amount of about 0.01% to about 2% by weight of the ink composition.

[0079] Corrosion inhibitors may be used in the inkjet ink compositions described herein. Suitable corrosion inhibitors include benzotriazole, and may be present in an amount of about 0.01% to about 2% by weight of the ink composition.

[0080] Inkjet ink composition

[0081] In one embodiment, the inkjet ink composition comprises:

[0082] Fluorescent colorants containing coumarin, ranging from approximately 0.3% by weight (w / w) to approximately 5% by weight (w / w).

[0083] At least approximately 50% by mass (w / w) of solvent,

[0084] A bonding resin comprising approximately 10% by weight (w / w) to approximately 30% by weight (w / w), and

[0085] Conductive agent of about 0.5% by weight (w / w) to about 5% by weight (w / w).

[0086] In one embodiment, any inkjet ink composition described herein has a viscosity of about 2.0 to about 6.0 centipoise at about 25°C, including about 2.0 centipoise, about 2.1 centipoise, about 2.2 centipoise, about 2.3 centipoise, about 2.4 centipoise, about 2.5 centipoise, about 2.6 centipoise, about 2.7 centipoise, about 2.8 centipoise, about 2.9 centipoise, about 3.0 centipoise, about 3.1 centipoise, about 3.2 centipoise, about 3.3 centipoise, about 3.4 centipoise, about 3.5 centipoise, about 3.6 centipoise, and about 6.0 centipoise. 3.7 centipoise, about 3.8 centipoise, about 3.9 centipoise, about 4.0 centipoise, about 4.1 centipoise, about 4.2 centipoise, about 4.3 centipoise, about 4.4 centipoise, about 4.5 centipoise, about 4.6 centipoise, about 4.7 centipoise, about 4.8 centipoise, about 4.9 centipoise, about 5.0 centipoise, about 5.1 centipoise, about 5.2 centipoise, about 5.3 centipoise, about 5.4 centipoise, about 5.5 centipoise, about 5.6 centipoise, about 5.7 centipoise, about 5.8 centipoise, about 5.9 centipoise, and about 6.0 centipoise. In one embodiment, any inkjet ink composition described herein has a viscosity of about 3.0 to about 5.0 centipoise at about 25°C.

[0087] In one embodiment, any inkjet ink composition described herein has a resistivity of about 1000 to about 2000 ohm-cm at about 25°C, including about 1000, about 1050, about 1100, about 1150, about 1200, about 1250, about 1300, about 1350, about 1400, about 1450, about 1500, about 1550, about 1600, about 1650, about 1700, about 1750, about 1800, about 1850, about 1900, about 1950 and about 2000 ohm-cm.

[0088] application

[0089] The inkjet compositions described herein (e.g., invisible fluorescent ink compositions containing one or more coumarins) are suitable for security printing and any other applications requiring codes to be invisible to the naked eye. Furthermore, the compositions described herein can also be used to mark defective materials on continuous films or foils in roll-to-roll applications, enabling subsequent in-line inspection on high-speed production lines and removal of defective portions of the film or foil using fluorescent sensors.

[0090] The present invention will be better understood by referring to the following examples, which are merely illustrative and not intended to limit the invention.

[0091] Example

[0092] Example A

[0093] The table below shows the solubility of the fluorescent dyes 7-diethylamino-4-methylcoumarin and 2,5-bis(5-tert-butyl-benzoxazol-2-yl)thiophene in specified solvents and temperatures.

[0094]

[0095] Example B

[0096] Inkjet ink formulations Examples 1-7 were prepared according to the components and amounts listed in the table below. Examples 1-7 used fluorescent whitening agent 140, which contains 7-diethylamino-4-methylcoumarin as a coumarin dye. The comparative formulation is dye A, a commercially available fluorescent inkjet formulation containing 2,5-bis(5-tert-butyl-benzoxazol-2-yl)thiophene as a dye. The general procedure for preparing these inkjet ink formulations includes the following steps: 1) dissolving and stirring all components one by one in an ink carrier; 2) filtering the ink solution.

[0097] Example B demonstrates that formulations 1-7 exhibit higher fluorescence intensity compared to the comparative examples. This example also shows that, for a given formulation, optimal fluorescence intensity can be achieved by optimizing the concentration of the dye in the formulation. For example, the fluorescence intensity of Examples 1-7 is approximately 3 times higher than that of the comparative examples.

[0098]

[0099]

[0100] Example C

[0101] The table below shows the average molecular weight of the specified resins as determined by gel permeation chromatography (GPC) (using polystyrene as a standard).

[0102]

[0103]

[0104] Example D

[0105] Inkjet ink formulations Examples 8-16 were prepared according to the components and amounts listed in the table below. The general procedure for preparing these inkjet ink formulations includes the following steps: 1) dissolving and mixing all components one by one in the ink carrier; 2) filtering the ink solution.

[0106] Example D shows that, generally, at the same dye concentration, fluorescence intensity increases with increasing total solids content.

[0107]

[0108]

[0109] While certain embodiments have been described and illustrated, it should be understood that those skilled in the art can make changes and modifications without departing from the technical scope defined in the following claims.

[0110] The embodiments illustrated herein may be suitably implemented in the absence of any element or feature not specifically disclosed herein, or any limitation or restriction. Therefore, terms such as “comprising,” “including,” and “containing” should be interpreted broadly and without limitation. Furthermore, the terms and expressions used herein are descriptive rather than restrictive, and their use is not intended to exclude any equivalents of the features shown and described or portions thereof, but it should be recognized that various modifications can be made within the scope of the claimed technology. Additionally, the phrase “consistently composed of” should be understood to include those specifically listed elements and those additional elements that do not materially affect the basic and novel characteristics of the claimed technology. The phrase “consisting of” excludes any unspecified elements.

[0111] This invention should not be limited to the specific embodiments described herein. Many modifications and variations can be made without departing from its spirit and scope, as will be apparent to those skilled in the art. From the foregoing description, those skilled in the art will understand that functionally equivalent methods and compositions within the scope of this invention, in addition to those listed herein. Such modifications and variations are intended to fall within the scope of the appended claims. This invention should be limited only by the terms of the appended claims and the full scope of their equivalents. It should be understood that this invention is not limited to specific methods, reagents, compounds, or compositions, which can, of course, be varied. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0112] Furthermore, when the features or aspects of the invention are described in accordance with the Markush group, those skilled in the art will recognize that the invention is therefore also described in accordance with any individual member or subgroup of members of the Markush group.

[0113] As those skilled in the art will understand, for any and all purposes, particularly in providing a written description, all scopes disclosed herein also encompass any and all possible subscopes and combinations thereof. Any listed scope can be readily identified as sufficiently descriptive and enabling the same scope to be decomposed into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each scope discussed herein can be readily decomposed into a lower third, a middle third, and an upper third, etc. As those skilled in the art will also understand, all language such as “up to,” “at least,” “greater than,” “less than,” etc., includes the referenced numbers and refers to a scope that can subsequently be decomposed into subscopes as described above. Finally, as those skilled in the art will understand, a scope includes each individual member.

[0114] All publications, patent applications, granted patents, and other documents referenced in this specification are incorporated herein by reference as if each individual publication, patent application, granted patent, or other document were specifically and individually indicated to be incorporated herein by reference in its entirety. Definitions contained in the text incorporated by reference are excluded if they conflict with definitions within this invention.

[0115] Other embodiments are described in the claims.

Claims

1. An inkjet ink composition comprising: Fluorescent colorants containing coumarin; Solvent; Adhesive resin; and Conductive agent.

2. The inkjet ink composition according to claim 1, wherein, The coumarin comprises 7-hydroxycoumarin or 7-(substituted amino)coumarin.

3. The inkjet ink composition according to claim 1 or 2, wherein, The coumarin comprises 7-diethylamino-4-methylcoumarin.

4. The inkjet ink composition according to claim 1, wherein, The coumarin does not contain 3-phenyl-7-(1,2H-naphthotriazolyl)-coumarin, and / or the fluorescent colorant does not contain 3-phenyl-7-(1,2H-naphthotriazolyl)-coumarin.

5. The inkjet ink composition according to any one of the preceding claims, wherein, The fluorescent colorant has one or more of the following properties: (a) The maximum absorption wavelength is from about 330 nanometers to about 400 nanometers, preferably from about 345 nanometers to about 385 nanometers; and (b) The peak emission wavelength is about 400 nanometers to about 600 nanometers, preferably about 430 nanometers to about 530 nanometers.

6. The inkjet ink composition according to any one of the preceding claims, wherein, The fluorescent colorant is present in an amount of about 0.3% to about 5% by weight of the composition, preferably in an amount of about 0.6% to about 3% by weight of the composition.

7. The inkjet ink composition according to any one of the preceding claims, wherein, The solvent comprises one or more of the following: ketones, esters, alcohols, lactates, glycols, glycol ethers, glycol ether acetates, and glycol ether esters.

8. The inkjet ink composition according to any one of the preceding claims, wherein, The solvent comprises one or more of the following: methyl ethyl ketone, methyl propyl ketone, diethyl ketone, methyl isopropyl ketone, cyclohexanone, cyclopentanone, acetone, ethanol, n-propanol, isopropanol, n-butanol, methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, ethyl lactate, butyl lactate, propylene glycol, and propylene glycol methyl ether acetate.

9. The inkjet ink composition according to any one of the preceding claims, wherein, The solvent is present in an amount of at least about 50% of the weight of the composition.

10. The inkjet ink composition according to claim 9, wherein, The solvent is present in an amount of about 50% to about 90% or about 75% to about 85% of the composition by weight.

11. The inkjet ink composition according to any one of the preceding claims, wherein, The adhesive resin comprises acrylic resin, styrene-acrylic resin, copolymer of styrene and allyl alcohol, ketone resin, aldehyde resin, polyketone resin, natural resin or modified natural resin (such as rosin ester and terpene modified resin), sulfonamide resin, sulfonamide-formaldehyde resin, toluenesulfonamide resin, bisphenol A toluenesulfonamide resin, cellulose ester (such as cellulose acetate butyrate and cellulose acetate propionate), cellulose ether (such as ethyl cellulose), polyvinyl butyral, polyurethane, phenolic resin, modified phenolic resin, polyamide resin, vinyl resin (e.g., copolymer of vinyl chloride and polyvinyl acetate, with or without a third monomer), poly... One or more of vinyl alcohol, polyvinyl acetate, nitrocellulose resin, polyester resin, and any combination thereof, preferably one or more of acrylic resin, styrene acrylic resin, copolymer of styrene and allyl alcohol, ketone resin, aldehyde resin, polyketone resin, natural resin or modified natural resin (such as rosin ester and terpene resin), sulfonamide resin, sulfonamide-formaldehyde resin, toluenesulfonamide resin, bisphenol A toluenesulfonamide resin, cellulose ether (such as ethyl cellulose), cellulose ester (such as cellulose acetate butyrate and cellulose acetate propionate), cellulose ether (such as ethyl cellulose), polyvinyl butyral, and any combination thereof.

12. The inkjet ink composition according to any one of the preceding claims, wherein, The bonding resin does not contain nitrocellulose.

13. The inkjet ink composition according to any one of the preceding claims, wherein, The adhesive resin comprises one or more adhesive resins with a weight average molecular weight of less than about 50,000 Daltons, preferably less than about 30,000 Daltons, and more preferably less than about 15,000 Daltons.

14. The inkjet ink composition according to any one of the preceding claims, wherein, The adhesive resin is present in an amount of about 10% to about 30% by weight of the composition, preferably about 15% to about 25%.

15. The inkjet ink composition according to any one of the preceding claims, wherein, The conductive agent comprises one or more of the following: organic ammonium salts, organic bromide salts, organic phosphonium salts, organic borates, and organic phosphates.

16. The inkjet ink composition according to any one of the preceding claims, wherein, The conductive agent comprises one or more tetraalkylammonium salts.

17. The inkjet ink composition according to any one of the preceding claims, wherein, The conductive agent comprises one or more of the following: tetrabutylammonium hexafluorophosphate, tetrapropylammonium hexafluorophosphate, tetraethylammonium hexafluorophosphate, tetramethylammonium hexafluorophosphate, tetrabutylammonium tetraphenylborate, tetrabutylammonium tetrabutylborate, tetramethylammonium bromide, tetraethylammonium bromide, tetrabutylammonium bromide, tetrapropylammonium bromide, and tetrabutylammonium nitrate.

18. The inkjet ink composition according to any one of the preceding claims, wherein, The conductive agent is present in an amount of about 0.5% to about 5% by weight of the composition, preferably about 1% to about 3%.

19. The inkjet ink composition according to any one of the preceding claims further comprises one or more of a humectant, a cosolvent, a resin, a defoamer, a tackifier, a plasticizer, a dispersant, a surfactant, and a corrosion inhibitor.

20. The inkjet ink composition according to any one of the preceding claims, wherein, The composition has a viscosity of about 2 to about 6 centipoise at about 25°C, preferably about 3 to about 5 centipoise at about 25°C, and / or the resistivity of the composition at about 25°C is in the range of about 1000 to about 2000 ohm-cm.

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