Hardening ink composition

Abstract

A curable ink composition, particularly a curable inkjet ink composition, is provided. The ink composition comprises a dye monomer, a carrier monomer, and an initiator. The dye monomer has a chromophore moiety covalently bonded to at least one polymerizable functional group and is present at 1.0% by weight or greater, based on the total weight of the ink composition. The carrier monomer has at least one polymerizable functional group and is present at 50% by weight or greater, based on the total weight of the ink composition. The ink composition is suitable for radiation curing, such as UV curing, and has good cure properties or lightfastness.

Description

Technical Field

[0001] Related Applications This application claims priority and the benefit thereof to UK Patent Application No. 1903147.5, filed on March 8, 2019 (08 / 03 / 2019), the content of which is hereby incorporated by reference in its entirety.

[0002] The present invention relates to curable ink compositions, particularly curable inkjet ink compositions. In particular, the ink is for radiation curing, such as UV curing.

Background Art

[0003] In ink compositions, it is necessary to balance several factors in order to avoid or reduce problems associated with the ink composition.

[0004] For curable inks, one or more monomers are usually present in the ink together with a polymerization initiator, such as a photoinitiator. After the ink composition is printed, the monomers polymerize to yield a cured printed deposit. The polymerization process is often referred to as curing. In the case of UV curable inks, the curing process involves treating the printed ink composition with UV radiation, such as UV light from light emitting diodes (LEDs) or mercury vapor arc lamps.

[0005] The monomers can be monofunctional or polyfunctional (e.g., difunctional or trifunctional) monomers. In the case of UV curing, the polymerization initiator is typically a photoinitiator.

[0006] Curable inks, such as UV curable inks, provide several favorable features compared to other types of inks. For example, curable inks can have a low content of volatile organic chemicals.

[0007] UV curable inks are typically colored by including pigments. Pigments are powdered substances that are relatively insoluble in the ink but can remain suspended therein.

[0008] Soluble dye compounds are not generally used in UV curable inks because, for example, they tend to degrade under strong UV light sources.

[0009] Pigments are typically more expensive than dyes and require an additional "grinding" step in ink manufacture, where the pigment is ground fine enough to be well suspended in the ink. Pigments are more likely to cause printer nozzle clogging than dyes.

[0010] One of the most important challenges for formulators of UV curable inks is how to properly suspend the colored pigments in the monomer solvent. In addition to optimizing the grinding conditions, it is necessary to properly match the desired pigments to the monomers and other additives in the ink, thereby creating a stable dispersion.

[0011] The ability to include dyes in the ink formulation may address some of these challenges and is therefore desirable.

[0012] However, most small molecule dyes decompose very rapidly when exposed to UV radiation, such as that used during the curing process. In addition, small molecule dyes are known to migrate out of the printed deposit, especially when a solvent is applied.

[0013] For a dye to be used in a UV curable ink, the dye must have certain properties such as the ability to withstand the UV radiation used to cure the ink, solubility in the ink composition, and compatibility with the printer hardware. For example, for drop-on-demand inkjet printing, the ink typically needs to have a low viscosity to be compatible with the printer hardware.

[0014] One solution to the problem of UV degradation of dyes is the provision of "polymeric dyes", which are polymers containing chromophores covalently bonded to the polymer chain. These polymeric dyes are not commercially available and require multiple synthetic steps. This dye also has a relatively high molecular weight that can increase viscosity.

[0015] It is also desirable for the ink to produce a printed deposit that maintains its color over a long period of time (i.e., color fastness), has good curing properties, and good adhesion to the substrate.

Prior Art Documents

Patent Documents

[0016]

Patent Document 1

Patent Document 2

Non-Patent Documents

[0017]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Non-Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0018] An object of the present invention is to provide an ink composition having some of the above desirable properties. In particular, an object of the present invention is to provide a dye compound that is stable to UV radiation and provides a composition having good curability and color fastness in a printed deposit.

[0019] It is an alternative and / or additional object of the present invention to overcome or address the problems of prior art ink compositions by using the ink composition of the present invention, or at least to provide a commercially useful alternative therefor.

Means for Solving the Problems

[0020] [Summary of the Invention] The present invention seeks to provide an ink composition suitable for curing and having good curing properties and / or good adhesion properties. In particular, the present invention seeks to provide a curable ink composition for use in drop-on-demand inkjet printing, such as piezoelectric drop-on-demand inkjet printing.

[0021] Thus, in one aspect, the present invention provides a curable ink composition comprising a dye monomer, a carrier monomer, and an initiator. The dye monomer has a chromophore moiety covalently bonded to at least one polymerizable functional group. The dye monomer is present at 1.0% by mass or more based on the total mass of the ink composition. The carrier monomer has at least one polymerizable functional group and is present at 50% by mass or more based on the total mass of the ink composition. The carrier monomer can be a single monomer or a combination of two or more monomers.

[0022] In this way, an ink composition having good curability and light resistance is provided.

[0023] It has been proposed that the dye moiety is stabilized by being covalently incorporated into the polymer network during the curing process.

[0024] In another aspect, the present invention provides a printed deposit formed from the curable ink composition of the present invention. The printed deposit includes a cured polymer film formed by the polymerization of dye monomers and carrier monomers.

[0025] The curable ink composition is compatible with the components of a printer, such as an inkjet printer, more specifically, a drop-on-demand inkjet printer, such as a piezoelectric drop-on-demand printer. The curable ink composition is suitable for direct application to a product and / or product packaging in order to achieve high-quality images.

[0026] Preferably, the curable ink composition described herein has a viscosity of about 0.5 to 30 mPa·s, more preferably 1 to 20 mPa·s, even more preferably 5 to 20 mPa·s at 25°C. Preferably, the curable ink composition described herein has a viscosity of less than 25 mPa·s, more preferably less than 15 mPa·s at 25°C. Preferably, the curable ink composition described herein has a viscosity greater than 3 mPa·s, more preferably greater than 5 mPa·s, even more preferably greater than 8 mPa·s at 25°C. The viscosity of the composition can be measured using a viscometer, such as a Brookfield DV-II+ viscometer.

[0027] The Brookfield DV-II+ viscometer is a rotational viscometer that measures viscosity by measuring the torque required to rotate an object within a fluid as a function of the viscosity of the fluid.

[0028] Preferably, the curable ink composition described in this specification has a surface tension of 20 to 50 mN / m, more preferably 20 to 40 mN / m at 25°C. The surface tension of the composition can be measured using a device such as a du Nouy ring tensiometer or by using the pendant drop method with a KSV Cam 200 optical tensiometer.

Brief Description of the Drawings

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[0030] [Detailed Description] The present invention aims to provide a curable ink composition that is suitable for radiation curing and has good curing properties and / or good adhesion properties. In particular, the present invention aims to provide a curable inkjet ink composition for use in drop-on-demand inkjet printing, for example piezoelectric drop-on-demand inkjet printing.

[0031] Accordingly, in one aspect, the present invention provides a curable ink composition comprising a dye monomer, a carrier monomer, and an initiator. The dye monomer has a chromophore moiety covalently bonded to at least one polymerizable functional group. The dye monomer is present in an amount of 1.0% by mass or more based on the total mass of the ink composition. The carrier monomer has at least one polymerizable functional group and is present in an amount of 50% by mass or more based on the total mass of the ink composition. The carrier monomer can be a single monomer or a combination of two or more monomers.

[0032] The curable ink composition can be a curable inkjet ink composition.

[0033] The curable ink composition can be a UV curable ink composition, for example, a UV curable inkjet ink composition for use in drop-on-demand inkjet printing.

[0034] In another aspect, the present invention provides a printed deposit formed from the ink composition of the present invention. The printed deposit (print deposit) includes a cured polymer film formed by the polymerization of a dye monomer and a carrier monomer.

[0035] The resulting printed ink deposit remains highly colored even after UV curing. It is proposed that the dye moiety is incorporated into the polymer structure of the cured film. Thus, the printed and cured deposit exhibits enhanced resistance to photofading compared to unreacted small molecule dyes on the surface.

[0036] Furthermore, the dye monomer provides color to the printed deposit, which means that pigments are no longer necessary in the ink. Since pigments significantly increase the viscosity of curable ink compositions, the addition of pigments to such ink compositions must be carefully controlled to achieve a viscosity compatible with the printer hardware. The present curable ink composition does not exhibit an increased viscosity.

[0037] The ink of the present invention is preferably for use in a piezoelectric inkjet printer such as a piezoelectric drop-on-demand inkjet printer. The viscosity and surface tension of the ink depend on the droplet size ejected by the printer and can be adjusted within the disclosed formulation principles to best match the characteristics of the printer.

[0038] Typically, in such printers, the ink is heated to about 40 °C to reduce the viscosity and facilitate ejection through the nozzles. For such applications, the viscosity is preferably 5 - 10 mPa·s at the application temperature, for example, at 40 °C.

[0039] The ink of the present invention can be useful for use in high-speed printing applications. Such applications require the release of droplets from the printer nozzles at a very high frequency, and the residence time under the UV curing device is short at high speeds. The ink of the present invention has a low viscosity required for high-speed release and exhibits improved curing enabling a high-speed curing process. Preferably, the ink should be capable of a printing speed of up to 50 m / min, more preferably up to 75 m / min, and even more preferably up to 100 m / min.

[0040] <Curable ink composition> The curable ink composition of the present invention includes a dye monomer, a carrier monomer, and an initiator. The dye monomer has a chromophore moiety covalently bonded to at least one polymerizable functional group. The dye monomer is present at 1.0% by mass or more based on the total mass of the ink composition. The carrier monomer has at least one polymerizable functional group and is present at 50% by mass or more based on the total mass of the ink composition. The initiator can be a photoinitiator. The carrier monomer can be a single monomer or a combination of two or more monomers. The curable ink composition is preferably a curable inkjet ink composition.

[0041] The term monomer as used in this application refers to a compound that can polymerize alone or together with other monomers to yield a polymer. In particular, in this application, the term monomer refers to a compound that can polymerize when exposed to UV radiation in the presence of an initiator.

[0042] Preferably, the curable ink composition described herein has a viscosity of about 0.5 to 30 mPa·s, more preferably 1 to 20 mPa·s, and even more preferably 5 to 20 mPa·s at 25°C. Preferably, the curable ink composition described herein has a viscosity of less than 25 mPa·s, more preferably less than 15 mPa·s at 25°C. Preferably, the curable ink composition described herein has a viscosity higher than 3 mPa·s, more preferably higher than 5 mPa·s, and even more preferably higher than 8 mPa·s at 25°C. The viscosity of the composition can be measured using a viscometer, such as a Brookfield DV-II+ viscometer.

[0043] The Brookfield DV-II+ viscometer is a rotational viscometer that measures viscosity by measuring the torque required to rotate an object within a fluid as a function of the viscosity of the fluid.

[0044] <Dye monomer> The curable ink composition includes a dye monomer having a chromophore moiety covalently bonded to at least one polymerizable functional group.

[0045] Methacrylated anthraquinone dyes have been synthesized in previous studies (see Dollendorf et al., Afsharnia et al., and McCurdy et al.). In these studies, the methacrylated anthraquinone dyes have been polymerized by using a radical initiator or by heating. In these studies, the dyes and the polymerizable compositions are for use as color stabilizers in paints, as photoresists in semiconductors, and for iridescent implants. Such compositions are not suitable for inks, particularly for inkjet printing inks.

[0046] Chromophore-containing monomers are also being discussed for use in coating applications (e.g., U.S. Patent No. 7,030,244 and U.S. Patent No. 6,870,063). In these cases, the chromophore-containing monomers are copolymerized for coating. As is typical in coating compositions prior to polymerization, the composition contains a large amount of reactive polymer (40% by weight), and as a result, contains a smaller amount of monomer. The coating is applied by spreading with a blade and cured at a low speed (less than 8 meters per minute). Therefore, these coating compositions are not suitable for printing techniques, especially inkjet, such as drop-on-demand inkjet printing.

[0047] U.S. Patent Application Publication No. 2009 / 0087575 discusses the use of sensitizing dyes. Sensitizing dyes are said to absorb radiation and transfer this energy to a polymerization initiator to initiate polymerization (see

[0031] ). Sensitizing dyes absorb UV light, and preferably, the sensitizing dyes have an absorption wavelength in the range of 350 nm to 450 nm (see

[0032] ). The preferred absorption pattern in U.S. Patent Application Publication No. 2009 / 0087575 means that the sensitizing dye appears colorless. U.S. Patent Application Publication No. 2009 / 0087575 explains that in order to provide a colored image, the ink composition contains additional colorants, which is the case of an example containing additional colorants.

[0048] In the case of UV printing, when the dye monomer is present in a composition suitable for inkjet printing to allow a curing process to occur that results in good curing, it is necessary to transmit sufficient light in the UV range. It is also desirable that the resulting printed deposit absorbs sufficient visible light for strong coloring and that the color is fast. The presently claimed curable ink composition provides these properties.

[0049] The term chromophore as used in connection with the present invention refers to a chemical group that imparts color to a dye monomer. A chromophore imparts color because it has two distinct molecular orbitals and the energy difference between them corresponds to the wavelength of light in the visible spectrum. When light strikes the chromophore, an electron is excited to a higher energy molecular orbital and the corresponding light is absorbed. The observed coloring is due to the light that is not absorbed because the wavelength of the light does not correspond to the energy difference between the previous molecular orbitals. In other words, the chromophore moiety imparts color by absorbing light in the visible spectrum.

[0050] The chromophore moiety may impart color by absorbing more than half of the light in the visible light spectrum. For example, the chromophore may be capable of absorbing 50% or more, preferably 60% or more, and even more preferably 80% or more of the light in the visible spectrum. The visible light spectrum is generally about 380 nm to 740 nm. Absorbance can be calculated by measuring the transmittance of a sample containing 5 ppm of the dye monomer using a spectrophotometer.

[0051] The chromophore moiety may be selected from anthraquinone, anthrapyridone, anthrapyrimidine, anthrapyrimidine, anthrapyrimidone, isothiazoloanthrone, azo dyes, bisazo dyes, methine, bismethine, coumarin, 3-aryl-2,5-dioxypyrroline, 3-aryl-5-dicyanomethylene-2-oxypyrroline, perinone, quinophthalone, phthalocyanine, metal phthalocyanine, nitroarylamine, or 2,5-diarylaminoterephthalic acid ester.

[0052] Preferably, the chromophore moiety is anthraquinone. Anthraquinone can be a single anthraquinone moiety or can be composed of two or more anthraquinone moieties, for example, 7,14-dibenzopyrenequinone or indanthrone.

[0053] The term anthraquinone can be used interchangeably with anthracene-9,10-dione or 9,10-dioxoanthracene.

[0054] The anthraquinone chromophore moiety can be provided by an anthraquinone dye covalently bonded to a polymerizable functional group via a suitable atom of the anthraquinone dye, such as a carbon, oxygen, nitrogen, or sulfur atom of the anthraquinone dye.

[0055] Anthraquinone dyes are well known and include Disperse Blue 14, Reactive Blue 4, Acid Blue 25, Alizarin, Anthrapurpurin, Carmine acid, 1,4-diamino-2,3-dihydroanthraquinone, 7,14-dibenzopyrenequinone, Indanthrone blue, Morindone, Oil Blue 35, Parietin, Quinizarine Green SS, Remazol Brilliant Blue R, Solvent Violet 13, 1,2,4-trihydroxyanthraquinone, Vat Orange 1.

[0056] The chromophore is covalently bonded to at least one polymerizable functional group. The covalent bond can exist between one or more suitable atoms in the chromophore, for example, by abstraction of a hydrogen atom from a carbon, nitrogen, oxygen, or sulfur atom in the chromophore. Each chromophore may optionally be substituted, for example, each chromophore may optionally be substituted with one or more halo, NH 2 , NHR', aryl, heteroaryl, -SO 3 H, -OH, C 1~6 alkyl, C 1~6 haloalkyl, C 1~6 alkoxy, -COOH, -CN, and glucosyl, where R’ can be C 1~6 alkyl, aryl-NH-heteroaryl, phenyl, tolyl, which may optionally be substituted with halo, -OH, -SO2 H, and -SO 2 CH 2 CH 2 OSO 3 It may be substituted with one or more groups selected from Na.

[0057] The dye monomer contains a polymerizable functional group. The polymerizable functional group can be an alkenyl, alkynyl, acrylate, methacrylate, maleate, fumarate, or acrylamide functional group. Preferably, the polymerizable functional group is methacrylate.

[0058] As used herein, the term methacrylate refers to a compound of the formula R-OC(=O)C(CH 3 )=CH 2 . In the case of a pigment monomer, the R group contains a chromophore moiety. Examples of methacrylate monomers are shown below.

[0059] As used herein, the term acrylate refers to a compound of the following formula R-OC(=O)C(H)=CH 2 . In the case of a pigment monomer, the R group contains a chromophore moiety. Examples of acrylate monomers are shown below.

[0060] The dye monomer can be a monofunctional monomer or a polyfunctional monomer. Preferably, the dye monomer is polyfunctional, more preferably difunctional.

[0061] As used in this context, the term "monofunctional monomer" refers to a monomer having exactly one polymerizable functional group, and the polymerization is, for example, radical polymerization.

[0062] As used in this context, the term "polyfunctional monomer" refers to a monomer having two or more (i.e., more than one) polymerizable functional groups, and the polymerization is, for example, radical polymerization. For example, a difunctional monomer is a type of polyfunctional monomer having exactly two polymerizable functional groups, and the polymerization is, for example, radical polymerization.

[0063] In some embodiments, the dye monomer is anthraquinone methacrylate, preferably anthraquinone dimethacrylate.

[0064] Examples of preferred dye monomers include the following: 3-[(9,10-dioxoanthracen-1-yl)amino]propyl 2-methylprop-2-enoate, 3-{[5-({3-[(2-methylprop-2-enoyl)oxy]propyl}amino)-9,10-dioxoanthracen-1-yl]amino}propyl 2-methylprop-2-enoate, 4-{[5-({4-[(2-methylprop-2-enoyl)oxy]phenyl}amino)-9,10-dioxoanthracen-1-yl]amino}phenyl 2-methylprop-1-enoate, 3-{[8-({3-[(2-methylprop-2-enoyl)oxy]propyl}amino)-9,10-dioxoanthracen-1-yl]amino}propyl 2-methylprop-2-enoate, and 4-{[8-({4-[(2-methylprop-2-enoyl)oxy]phenyl}amino)-9,10-dioxoanthracen-1-yl]amino}phenyl 2-methylprop-2-enoate.

[0065] The amount of the dye monomer in the curable ink composition is 0.5% by mass or more based on the total mass of the ink composition.

[0066] Preferably, the dye monomer is present in an amount of 1.0% by mass or more, preferably 2% by mass or more, and even more preferably 4% by mass or more based on the total mass of the ink composition.

[0067] Preferably, the dye monomer is present in an amount of 30% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less based on the total mass of the ink composition.

[0068] The dye monomer can be present in an amount within the range of the upper and lower limits selected from the amounts described above. For example, the dye monomer can be present in an amount of 1.0 to 10% by mass based on the total mass of the ink composition.

[0069] Preferably, the dye monomer has a molecular weight greater than 100, more preferably greater than 200, even more preferably greater than 300, such as a weight average molecular weight (Mw).

[0070] Preferably, the dye monomer has a molecular weight less than 2000, more preferably less than 1500, even more preferably less than 1,000, such as a weight average molecular weight (Mw).

[0071] The dye monomer can have a molecular weight, such as a weight average molecular weight (Mw), within a range having an upper limit and a lower limit selected from the amounts described above. Preferably, the dye monomer has a molecular weight between 100 and 2000, more preferably between 100 and 2,000, more preferably between 100 and 1,000, more preferably between 200 and 1,000, even more preferably between 300 and 1,000, such as a weight average molecular weight (Mw).

[0072] <Carrier monomer (carrier monomer)> The curable ink composition contains a carrier monomer. The carrier monomer has at least one functional group capable of polymerizing and is present at 50% by mass or more based on the total mass of the ink composition.

[0073] The carrier monomer can be a single monomer or a combination of two or more monomers. Preferably, the carrier monomer is a single monomer.

[0074] The polymerizable functional group of the carrier monomer can be alkenyl, alkynyl, acrylate, methacrylate, maleate, fumarate, acrylamide functional group, or a mixture thereof. Preferably, the polymerizable functional group is acrylate.

[0075] The carrier monomer is selected to be compatible with the dye monomer. In this way, the carrier monomer and the dye monomer copolymerize.

[0076] The carrier monomer can be monofunctional or can be polyfunctional. Preferably, the carrier monomer is polyfunctional, more preferably bifunctional. When the carrier monomer is a combination of two or more monomers, each monomer is preferably polyfunctional, more preferably bifunctional.

[0077] It is presented that polyfunctional monomers are incorporated into the network more effectively than monofunctional monomers.

[0078] Suitable monofunctional monomers include monofunctional acrylates, monofunctional acrylamides, monofunctional vinyl compounds, monofunctional methacrylates, monofunctional allyl ethers, monofunctional maleates, monofunctional fumarates, monofunctional methacrylamides, or mixtures thereof.

[0079] Suitable monofunctional acrylates include caprolactone acrylate, cyclic trimethylolpropane formal acrylate, ethoxylated nonylphenol acrylate, isodecyl acrylate, isooctyl acrylate, octyldecyl acrylate, alkoxylated phenol acrylate, tridecyl acrylate, isoamyl acrylate, stearyl acrylate, lauryl acrylate, octyl acrylate, decyl acrylate, isoamyl stil acrylate, isostearyl acrylate, 2-ethylhexyl diglycol acrylate, 2-hydroxybutyl acrylate, butoxyethyl acrylate, ethoxydiethylene glycol acrylate, methoxydiethylene glycol acrylate, methoxypolyethylene glycol acrylate, methoxypropylene glycol acrylate, phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, isobornyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-acryloyloxyethyl succinate, 2-acryloxyethyl phthalate, 2-acryloxyethyl-2-hydroxyethyl-phthalate, lactone-modified flexible acrylate, or t-butylcyclohexyl acrylate.

[0080] Suitable monofunctional acrylamides include acryloylmorpholine, N-isopropylacrylamide, N-tert-butylacrylamide, diacetoneacrylamide.

[0081] Suitable monofunctional vinyl compounds include vinyl ethers such as ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, cyclohexyl vinyl ether, 2-ethylhexyl vinyl ether, dodecyl vinyl ether, octadecyl vinyl ether, or hydroxybutyl vinyl ether, and vinyl amides such as N-vinylcaprolactam, N-vinylpyrrolidone, N-methyl-N-vinylacetamide, prN-vinylimidazole.

[0082] Suitable polyfunctional monomers can have two or more functional groups selected from alkenyl, alkynyl, acrylate, maleate, fumarate, or acrylamide functional groups.

[0083] Suitable polyfunctional acrylate monomers include hexanediol diacrylate (e.g., 1,6 - hexanediol diacrylate), 3 - methyl - 1,5 - pentanediyl diacrylate, di - trimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, ethoxylated pentaerythritol tetraacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, 1,4 - butanediol diacrylate, 1,9 - nonanediol diacrylate, neopentyl glycol diacrylate, dimethylol - tricyclodecane diacrylate, bisphenol A EO (ethylene oxide) adduct diacrylate, bisphenol A PO (propylene oxide) adduct diacrylate, hydroxypivalate neopentyl glycol diacrylate, propoxylated neopentyl glycol diacrylate, alkoxylated dimethylol tricyclodecane diacrylate, and polytetramethylene glycol diacrylate, trimethylolpropane triacrylate, EO - modified trimethylolpropane triacrylate, tri(propylene glycol) triacrylate, caprolactone - modified trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, glyceryl propoxytriacrylate, or caprolactam - modified dipentaerythritol hexaacrylate.

[0084] Suitable polyfunctional vinyl monomers include 1,4-butanediol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, polyethylene glycol divinyl ether, and 1,4-cyclohexanedimethanol divinyl ether.

[0085] Preferably, the carrier monomer is a polyfunctional acrylate monomer, such as a bifunctional acrylate monomer. The bifunctional acrylate monomer may be dipropylene glycol diacrylate. When the carrier monomer is a combination of two or more monomers, each monomer is preferably a polyfunctional acrylate monomer, such as a bifunctional acrylate monomer.

[0086] In some cases, the carrier monomer is a bifunctional acrylate monomer and the dye monomer is a bifunctional methacrylate monomer. Preferably, the chromophore portion of the dye monomer is anthraquinone.

[0087] In this way, the acrylate carrier monomer provides a fast curing rate and is compatible with the methacrylate dye monomer. When acrylate and methacrylate are copolymerized, it is suggested that since the growing chain ends being methacrylate ends is energetically preferred, the polymer tends to be rich in methacrylate. In this way, most of the relatively small amount of dye monomer (compared to the amount of carrier monomer) is incorporated while maintaining a fast curing rate.

[0088] The amount of the carrier monomer in the curable ink composition is 50% by mass or more based on the total mass of the ink composition.

[0089] Preferably, the carrier monomer is present in an amount of 50% by mass or more, preferably 60% by mass or more, and even more preferably 70% by mass or more based on the total mass of the ink composition.

[0090] Preferably, the carrier monomer is present in an amount of 90% by mass or less, more preferably 85% by mass or less, even more preferably 80% by mass or less, based on the total mass of the ink composition.

[0091] The carrier monomer can be present in an amount within a range of an upper limit and a lower limit selected from the amounts described above. For example, the dye monomer can be present in an amount of 60 to 80% by mass based on the total mass of the ink composition.

[0092] Preferably, the carrier monomer has a molecular weight greater than 30, more preferably greater than 50, even more preferably greater than 100, for example, a mass average molecular weight (Mw).

[0093] Preferably, the carrier monomer has a molecular weight of less than 1000, more preferably less than 500, more preferably less than 400, even more preferably less than 200, for example, a mass average molecular weight (Mw).

[0094] The carrier monomer can have a molecular weight, for example, a mass average molecular weight (Mw), within a range having an upper limit and a lower limit selected from the amounts described above. Preferably, the carrier monomer has a weight average molecular weight (Mw) between 30 and 1000, more preferably between 30 and 500, more preferably between 50 and 500, more preferably between 50 and 400, even more preferably between 100 and 200. When the carrier monomer is a combination of two or more monomers, each monomer preferably has the molecular weight disclosed above.

[0095] <Initiator> The curable ink composition contains an initiator. The initiator can be a thermal initiator or a photoinitiator, and preferably, the initiator is a photoinitiator.

[0096] The term initiator refers to a compound that reacts upon an external stimulus to generate reactive species, such as radicals. The external stimulus can be the use of UV radiation, thermal radiation, chemically active radiation, or an electron beam. The reactive species react with one or more monomers to initiate a polymerization reaction.

[0097] The initiator may be a photoinitiator.

[0098] The term photoinitiator refers to a compound that undergoes a photoreaction upon absorption of light to generate reactive species, such as radicals. The external stimulus may be visible light or UV radiation, and preferably, the external stimulus is UV radiation. The generated reactive species react with one or more monomers to initiate a polymerization reaction.

[0099] The photoinitiator can provide this function when irradiated with light (i.e., UV radiation) having a wavelength in the range of 450 - 300 nm. This may mean that the photoinitiator has light absorption characteristics within the entire wavelength range of 450 - 300 nm.

[0100] The photoinitiator can be selected to absorb light at frequencies at which the chromophore does not absorb light. For example, phosphine oxide has an absorption peak around 360 - 400 nm. The red anthraquinone chromophore has a minimum absorption value in this range. Thus, the chromophore portion does not absorb the radiation applied to initiate the reaction.

[0101] Photoinitiators are well known in the art. The photoinitiator is selected from benzyl ketals, α - hydroxyalkylphenones (e.g., α - hydroxyacetophenones, such as the difunctional alpha hydroxyl ketone or 2 - hydroxy - 1 - [4 - [[4 - (2 - hydroxy - 2 - methylpropanoyl)phenyl]methyl]phenyl] - 2 - methyl - propane - 1 - one discussed later), α - aminoacetophenones, phosphine oxides (e.g., TPO), benzophenones, ketosulfones, thioxanthones, benzoyl formate esters, or mixtures thereof. Preferably, the photoinitiator is selected from TPO and benzophenone. More preferably, the photoinitiator is a mixture of TPO and benzophenone.

[0102] Preferably, the total amount of the photoinitiator is 30% by mass or less, more preferably 20% by mass or less, and even more preferably 17% by mass or less based on the total mass of the ink composition.

[0103] Preferably, the total amount of the photoinitiator is 5% by mass or more, preferably 8% by mass or more, and even more preferably 10% by mass or more based on the total mass of the ink composition.

[0104] The total amount of the photoinitiator may be an amount within a range having an upper limit and a lower limit selected from the amounts described above. For example, the total amount of the photoinitiator is 10 to 20% by mass based on the total mass of the ink composition.

[0105] <Solvent> The ink of the present invention may contain a solvent, for example, an organic solvent. In this way, the dye monomer can be completely solubilized in the curable ink composition.

[0106] The organic solvent can be selected from dichloromethane (DCM), acetone, methyl ethyl ketone, methyl propyl ketone, methyl isobutyl ketone, cyclohexanone, ethanol, isopropanol, n-propanol, isobutanol, n-butanol, sec-butanol, methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, t-butyl acetate, n-amyl acetate, isoamyl acetate, isobutyl isobutyrate, ethylene glycol, propylene glycol, 1-methoxy-2-propanol, and 1-methoxy-2-propyl acetate, dimethyl carbonate, propylene carbonate, dimethyl succinate, dimethyl glutarate, dimethyl adipate, butyl diglycol acetate, or a mixture thereof.

[0107] In some cases, the solvent may be present in less than 95% by mass, more preferably less than 80% by mass, and even more preferably less than 60% by mass based on the total mass of the ink composition. Preferably, the solvent is present in more than 10% by mass, preferably more than 30% by mass, and even more preferably more than 50% by mass based on the total mass of the ink composition. The solvent may be present in an amount within the range of the upper and lower limits selected from the amounts described above. In particular, when the ink of the present invention is for CIJ or TIJ printing, the ink has the above-described solvent amount.

[0108] When present, water may be present in 10% by mass or less, preferably 5% by mass or less, and even more preferably 1% by mass or less based on the total mass of the ink composition.

[0109] Preferably, the ink of the present invention is substantially free of volatile organic solvents and water. In particular, when the ink of the present invention is for drop-on-demand inkjet printing, for example, piezoelectric drop-on-demand inkjet printing, the ink preferably does not contain volatile organic solvents and water.

[0110] The solvent may be present in less than 20% by mass, more preferably less than 10% by mass, and even more preferably less than 7% by mass based on the total mass of the ink composition. In some cases, the solvent is present in more than 1% by mass, preferably more than 3% by mass, and even more preferably more than 4% by mass based on the total mass of the ink composition. The solvent may be present in an amount within the range of the upper and lower limits selected from the amounts described above. In particular, when the ink of the present invention is for drop-on-demand inkjet printing, for example, piezoelectric drop-on-demand inkjet printing, the ink has the above-described solvent amount.

[0111] <amine-functional material> The ink of the present invention may further contain an amine compound.

[0112] Inks of the present formulation may have a low viscosity in order to enhance compatibility with drop-on-demand printers, such as piezoelectric drop-on-demand printers.

[0113] Low viscosity formulations are particularly susceptible to inhibition by oxygen because oxygen can diffuse more rapidly into the printed film. The presence of oxygen interferes with the proper growth (propagation) of free radical reactions, which can prevent curing from being completed, especially at the surface of the ink after exposure to ultraviolet light.

[0114] Amines have been proposed to provide a source of abstractable hydrogen atoms for quenching reactive oxygen species. Amines have also been proposed to recycle peroxy radicals formed as a result of reaction with oxygen. This means that the radicals are not lost to the system and are returned in a form that can support further polymerization via the amine.

[0115] Thus, the presence of amines can improve curing performance. Amine compounds, particularly oligomeric amine compounds, have also been proposed to make a positive contribution to the toughness and adhesion of the cured ink film.

[0116] The amine compound can be any type of amine-containing compound, such as a small molecule amine, an amine-functional oligomer, or an amine-functional polymer. The amine can be a primary, secondary, or tertiary amine. A primary amine is an amine having one non-hydrogen substituent (i.e., NRH 2 ). A secondary amine is an amine having two non-hydrogen substituents (i.e., NRR’H). A tertiary amine is an amine having three non-hydrogen substituents (i.e., NRR’R’’). Preferably, the amine is a secondary or tertiary amine, more preferably a tertiary amine.

[0117] Preferably, the amine compound is an amine acrylate or an amine oligomer. In some cases, the amine acrylate is an amine-functional acrylate oligomer. Examples of amine-functional acrylates include aminated polyether acrylate oligomers (e.g., Ebecryl 7100 and Ebecryl LEO 10552). Examples of amine oligomers include Genomer 5695 and Genomer 5275.

[0118] Preferably, the amine compound has a molecular weight, such as a weight-average molecular weight (Mw), in the range of 200 to 10,000, more preferably in the range of 200 to 5,000, more preferably in the range of 500 to 5,000, more preferably in the range of 200 to 1,000, and even more preferably in the range of 500 to 1,000.

[0119] Preferably, the amine compound is present in less than 25% by mass, more preferably in less than 15% by mass, and even more preferably in less than 10% by mass, based on the total mass of the ink composition.

[0120] Preferably, the amine compound is present in more than 1% by mass, preferably in more than 2% by mass, and even more preferably in more than 5% by mass, based on the total mass of the ink composition.

[0121] The amine compound can be present in an amount within the range of the upper and lower limits selected from the amounts described above.

[0122] <Additional colorant> The ink composition and the printed deposit may further contain an additional colorant. The additional colorant is not particularly limited, and any suitable colorant known in the art can be used.

[0123] The incorporation of an additional colorant can provide additional properties to the ink. For example, the incorporation of an additional white colorant can result in an opaque film.

[0124] The additional colorant may be a dye or a pigment. Preferably, the additional colorant is a pigment. The pigment can be an inorganic pigment or an organic pigment.

[0125] Preferably, the pigment has an average particle diameter of less than 1 μm. The average particle diameter referred to here is the Z-average particle diameter calculated using the dynamic light scattering method. This is the intensity-weighted average hydrodynamic size of the particle aggregates.

[0126] The organic pigment can be selected from azo pigments (including azo lakes, insoluble azo pigments, condensed azo pigments, and chelate azo pigments), polycyclic pigments (e.g., phthalocyanine, perylene, perinone, anthraquinone, quinacridone, dioxazine, thioindigo, isoindolinone, quinophthalone pigments), dye-type chelate pigments (e.g., basic dye-type chelate pigments and acidic dye-type chelate pigments), nitro pigments, nitroso pigments, aniline black, and carbon black.

[0127] The carbon black used for the ink of the present invention includes carbon black manufactured by Mitsubishi Chemical Corporation, such as No. 2300, No. 900, MCF 88, No. 33, No. 40, No. 45, No. 52, MA 7, MA 8, MA 100, and No. 2200 B; carbon black manufactured by Columbian Carbon Co. Ltd, such as Raven 5750, Raven 5250, Raven 5000, Raven 3500, Raven 1255, and Raven 700; carbon black manufactured by Cabot Corporation, such as Regal 400 R, Regal 330 R, Regal 660 R, Mogul L, Mogul E, Monarch 700, Monarch 800, Monarch 880, Monarch 900, Monarch 1000, Monarch 1100, Monarch 1300, and Monarch 1400; and carbon black manufactured by Degussa, such as Color Black FW 1, Color Black FW 2, Color Black FW 2V, Color Black FW 18, Color Black FW 200, Color Black S 150, Color Black S 160, Color Black S 170, Printex 35, Printex U, Printex V, Printex 140 U, Special Black 6, Special Black 5, Special Black 4A, and Special Black 4.

[0128] Pigments for yellow ink include C.I. Pigment Yellow 1, C.I. Pigment Yellow 2, C.I. Pigment Yellow 3, C.I. Pigment Yellow 12, C.I. Pigment Yellow 13, C.I. Pigment Yellow 14, C.I. Pigment Yellow 16, C.I. Pigment Yellow 17, C.I. Pigment Yellow 73, C.I. Pigment Yellow 74, C.I. Pigment Yellow 75, C.I. Pigment Yellow 83, C.I. Pigment Yellow 93, C.I. Pigment Yellow 95, C.I. Pigment Yellow 97, C.I. Pigment Yellow 98, C.I. Pigment Yellow 109, C.I. Pigment Yellow 110, C.I. Pigment Yellow 114, C.I. Pigment Yellow 128, C.I. Pigment Yellow 129, C.I. Pigment Yellow 138, C.I. Pigment Yellow 150, C.I. Pigment Yellow 151, C.I. Pigment Yellow 154, C.I. Pigment Yellow 155, C.I. Pigment Yellow 180, C.I. Pigment Yellow 185, and C.I. Pigment Yellow 139.

[0129] 0 Pigments for orange ink include C.I. Pigment Orange 64 and C.I. Pigment Orange 73. Pigments for magenta ink include C.I. Pigment Red 5, C.I. Pigment Red 7, C.I. Pigment Red 12, C.I. Pigment Red 48 (Ca), C.I. Pigment Red 48:8 (Mn), C.I. Pigment Red 57 (Ca), C.I. Pigment Red 57:1, C.I. Pigment Red 112, C.I. Pigment Red 122, C.I. Pigment Red 123, C.I. Pigment Red 168, C.I. Pigment Red 184, C.I. Pigment Red 202, C.I. Pigment Red 176, C.I. Pigment Red 254, C.I. Pigment Red 255, C.I. Pigment Red 272, C.I. Pigment Red 254, C.I. Pigment Violet 19.

[0130] Pigments for cyan ink include C.I. Pigment Blue 1, C.I. Pigment Blue 2, C.I. Pigment Blue 3, C.I. Pigment Blue 15:2, C.I. Pigment Blue 15:3, C.I. Pigment Blue 15:4, C.I. Pigment Blue 15:34, C.I. Pigment Blue 16, C.I. Pigment Blue 22, C.I. Pigment Blue 60, C.I. Vat Blue 4, C.I. Vat Blue 60.

[0131] Pigments for green ink include C.I. Pigment Green 3 and C.I. Pigment Green 7.

[0132] Pigments for violet ink include C.I. Pigment Violet 23 and C.I. Pigment Violet 37.

[0133] The pigment for the white ink includes C.I. Pigment White 6.

[0134] Preferably, the organic pigment is selected from C.I. Pigment Yellow 83, C.I. Pigment Yellow 138, C.I. Pigment Yellow 139, C.I. Pigment Yellow 150, C.I. Pigment Yellow 151, Pigment Yellow 154, C.I. Pigment Yellow 155, C.I. Pigment Yellow 185, C.I. Pigment Orange 43, Pigment Orange 64, C.I. Pigment Orange 73, C.I. Pigment Red 122, C.I. Pigment Red 176, C.I. Pigment Red 254, C.I. Pigment Red 255, C.I. Pigment Red 272, C.I. Pigment Blue 15:3, C.I. Pigment Blue 15:4, C.I. Pigment Green 7, C.I. Pigment Violet 19, C.I. Pigment Violet 23, Pigment Black 7, and carbon black.

[0135] When the additional colorant is a pigment, the pigment may be in the form of a dispersion in the composition. The pigment dispersion may contain a dispersant or one or more monomer components present in the ink.

[0136] The additional colorant may be a dye soluble in oil or a solvent.

[0137] Examples of yellow dyes include aryl or heteroaryl azo dyes having a coupling component, for example, phenol, naphthol, aniline, pyrazolone, pyridone, or an open-chain active methylene compound; azomethine dyes having a coupling component, for example, an open-chain active methylene compound; methine dyes, for example, benzylidene dyes and monomethine oxonol dyes; quinone dyes, for example, naphthoquinone dyes and anthraquinone dyes; and other dye species, for example, quinophthalone dyes, nitro / nitroso dyes, acridine dyes, and acridinone dyes.

[0138] Examples of magenta dyes include aryl or heteroaryl azo dyes having a coupling component, for example, phenol, naphthol, or aniline; azomethine dyes having a coupling component, for example, pyrazolone or pyrazolotriazole; methine dyes, for example, arylidene dyes, styryl dyes, merocyanine dyes, and oxonol dyes; carbonium dyes, for example, diphenylmethane dyes, triphenylmethane dyes, and xanthene dyes; quinone dyes, for example, naphthoquinones, anthraquinones, or anthrapyridones; and condensed polycyclic dyes, for example, dioxazine dyes.

[0139] Examples of cyan dyes include azomethine dyes having a coupling component, for example, pyrrolotriazole, indoaniline dyes, and indophenol dyes; polymethine dyes, for example, cyanine dyes, oxonol dyes, and merocyanine dyes; carbonium dyes, for example, diphenylmethane dyes, triphenylmethane dyes, and xanthene dyes; phthalocyanine dyes; anthraquinone dyes; aryl or heteroaryl azo dyes having a coupling component, for example, phenol, naphthol, or aniline; and indigo / thioindigo dyes.

[0140] Preferably, the further colorant is present between 1 and 25% by mass, more preferably between 1.5 and 15% by mass, and most preferably between 2 and 8% by mass based on the total mass of the ink composition.

[0141] Preferably, the additional colorant is present in an amount of less than 25% by mass, more preferably less than 15% by mass, even more preferably less than 10% by mass, based on the total mass of the ink composition.

[0142] Preferably, the additional colorant is present in an amount of more than 1% by mass, preferably more than 1.5% by mass, even more preferably more than 2% by mass, based on the total mass of the ink composition.

[0143] The additional colorant can be present in an amount within a range having an upper limit and a lower limit selected from the amounts described above.

[0144] <Oligomer> The curable ink composition of the present invention can further contain an oligomer.

[0145] In some cases, the oligomer is polymerizable. That is, the oligomer contains functional groups capable of undergoing polymerization. Preferably, the oligomer is UV curable.

[0146] In this way, the curing of the ink can be improved.

[0147] UV curable oligomers suitable for use in the inks of the present invention include urethane acrylate, polyester acrylate, polyether acrylate, epoxy acrylate, and acrylic acrylate. Preferably, the oligomer is a polyether acrylate, for example, an aminated polyether acrylate (e.g., Ebecryl Leo 10552). In the case of an aminated polyether acrylate, the same compound provides both an oligomer and an amine compound to the ink composition.

[0148] Preferably, the oligomer has a molecular weight, for example, a mass average molecular weight (Mw) of 200 to 50,000, more preferably 300 to 5,000, more preferably 500 to 3,000, even more preferably 500 to 2,000.

[0149] Preferably, the oligomer is present in less than 25% by mass, more preferably less than 15% by mass, even more preferably less than 10% by mass based on the total mass of the ink composition.

[0150] Preferably, the oligomer is present in more than 1% by mass, preferably more than 2% by mass, even more preferably more than 5% by mass based on the total mass of the ink composition.

[0151] The oligomer can be present in an amount within the range of the upper and lower limits selected from the amounts described above.

[0152] <Method and Use> The present disclosure provides a method for printing a marking on a substrate. The curable ink composition of the present invention can be printed using an inkjet printer, and the method includes directing a flow of droplets of the ink composition onto the substrate and curing the printed ink composition by treating the printed ink composition, for example, with UV radiation.

[0153] The ink composition is formulated by mixing the components using methods known in the art.

[0154] The curing process can be carried out by applying thermal radiation, actinic radiation, by using electron beams, or by treating the printed ink composition with UV radiation. Preferably, the curing process is carried out by treating the printed ink composition with UV radiation.

[0155] The inkjet printer can be a thermal inkjet printer (i.e., a TIJ printer), a continuous inkjet printer (i.e., a CIJ printer), or a drop-on-demand inkjet printer (i.e., a DOD printer).

[0156] Preferably, the inkjet printer is a drop-on-demand inkjet printer, for example, a piezoelectric drop-on-demand inkjet printer. In some preferred cases, the ink is applied to the substrate using a high-resolution drop-on-demand printer that can eject droplet sizes in the range of less than 20 pl volume.

[0157] When applied to the substrate, the ink of the present invention is cured. The curing process promotes the polymerization of the monomers in the ink composition to result in a printed deposit. The curing process is initiated by an initiator.

[0158] The curing process can be a UV curing process. In such cases, the initiator is a photoinitiator. The UV curing process can include a single application of UV radiation or multiple applications of UV radiation. In some cases, the UV curing process includes two applications of UV radiation.

[0159] In some cases, the first (or only) application of UV radiation is provided by an LED. The LED preferably emits light in the range of 365 nm to 405 nm.

[0160] Preferably, the first application of UV radiation is 20 - 500 mJ / cm 2 、more preferably 50 - 200 mJ / cm 2 (measured as UVA2 using an EIT power pack) and provides a dose of 395 nm light delivered.

[0161] Preferably, the first application of UV radiation is performed immediately after printing, for example, using an LED disposed immediately adjacent to the print head. In this way, the ink is at least partially cured immediately after printing, preventing further spreading of the ink across the substrate.

[0162] In some cases, the first application of UV radiation is sufficient to cure the ink.

[0163] In other cases, additional application of UV radiation is necessary. This applies in particular to printing speeds of up to 50 m / min, more preferably up to 75 m / min. In these cases, the additional application of UV radiation is preferably effected by means of a mercury arc source. For the additional application of UV radiation, the dose of UVA is preferably 30 - 1000 mJ / cm 2 and more preferably 50 - 300 mJ / cm 2 (measured by an EIT power map).

[0164] In a further embodiment, the printing is carried out using a multi-pass inkjet printer. In this case, a UV light source, preferably an LED, is attached to the print head carriage. In this way, UV light can be applied after each successive row of printing.

[0165] <substrate> The present disclosure provides a method for printing a marking on a substrate. According to the invention, it is possible to print on any suitable substrate.

[0166] Examples of suitable substrates include porous substrates such as uncoated paper, semi-porous substrates such as aqueous coated paper, clay coated paper, silica coated paper, UV overcoated paper, polymer overcoated paper, and varnish overcoated paper, and non-porous substrates such as rigid plastics, polymer films, polymer laminates, metals, metal foil laminates, glass, and ceramics. The paper substrate can be a thin sheet of paper, roll paper, or ball paper. The plastic, laminate, metal, glass, and ceramic substrates can be in any suitable form, such as a bottle or container, plate, rod, cylinder, etc.

[0167] The curable ink composition of the present invention is particularly suitable for printing on non-porous materials, such as non-porous materials used in food packaging.

[0168] In many cases, the substrate is a plastic film, paper, or ball paper.

[0169] Suitable examples of plastic films include films containing polyethylene, polypropylene, polyester, polyamide, PVC, polylactic acid, or cellulose films. The plastic film can be pretreated or coated, for example, to improve the adhesion of the ink or to make it more suitable for the intended use.

[0170] Metal films, such as those used for lid applications, glass, and ceramics can also be printed.

[0171] Advantageously, by using the compositions and methods described herein, at least some of the above-described problems are overcome and / or alleviated, providing improved quality printing.

[0172] <Additive> The curable ink composition and / or the printed deposit can include additional components, such as those common in the art (see, for example, EP 2070998 and EP 1788045).

[0173] The ink composition and / or the printed deposit can further include one or more stabilizers (e.g., light stabilizers), preservatives (e.g., antioxidants, anti-aging agents), humectants, surfactants, conductive salts, wetting agents, surface treatment agents, adhesion promoting additives, dispersants, tackifiers, biocides, preservatives, crosslinking accelerators, polymerization inhibitors, plasticizers, pH adjusters, defoamers, and mixtures of two or more thereof. Preferably, the ink composition further includes one or more stabilizers (e.g., light stabilizers), conductive salts, or wetting agents.

[0174] <Stabilizer> Preferably, the ink composition and / or the printed deposit further includes a stabilizer.

[0175] In some cases, it has been suggested that the ejection performance of an inkjet ink is affected by its viscosity. Unwanted free radical polymerization, for example, unwanted free radical polymerization of acrylate or vinyl ether groups, can lead to an increase in viscosity. Stabilizers can be used to prevent unwanted free radical polymerization. For example, a stabilizer can act as a polymerization inhibitor to avoid even low levels of free radical polymerization in the ink during storage or before use.

[0176] Suitable stabilizers include p-methoxyphenol (MEHQ), butylated hydroxytoluene (BHT), quinone methide, cupferron - Al, and TEMPO.

[0177] Preferably, the stabilizer is present at 0.1 to 5% by mass based on the total mass of the ink composition.

[0178] <Conductive Additive> For continuous inkjet applications, the ink composition and / or the printed deposit may further contain a conductive additive. The conductive additive can be any organic salt known in the art.

[0179] Conductive additives for ink compositions are well known in the art.

[0180] Preferably, the organic salt is selected from quaternary ammonium salts or phosphonium salts. For example, the organic salt is selected from tetraethylammonium chloride, tetraethylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium acetate, tetrabutylammonium nitrate, tetrabutylammonium tetrafluoroborate, tetrabutylammonium hexafluorophosphate, tetrabutylphosphonium chloride, and tetrabutylphosphonium bromide.

[0181] Preferably, the conductive additive is present at 0.1 to 5% by mass based on the total mass of the ink composition.

[0182] <Wetting agent> The ink composition and / or the printed deposit may further contain a wetting agent.

[0183] Wetting agents for ink compositions are well known in the art. The wetting agent can be a silicone-based wetting agent, for example, a silicone polyether acrylate wetting agent, for example, TEGO Rad 2300.

[0184] Preferably, the wetting agent is present at 0.1 to 5% by mass, more preferably 1 to 2% by mass based on the total mass of the ink composition.

[0185] <Humectant> The ink composition and / or the printed deposit may further contain a humectant.

[0186] Suitable humectants include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,4-cyclohexanedimethanol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,2-propanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, glycerol, 1,2,6-hexanetriol, sorbitol, 2-pyrrolidone, 2-propanediol, butyrol acetone, tetrahydrofurfuryl alcohol, and 1,2,4-butanetriol, and mixtures of two or more thereof.

[0187] The ink composition may contain a humectant and a solvent in a ratio of about 1:1.

[0188] The ink composition may contain up to a total of 30% by mass of humectant, based on the total mass of the composition. More preferably, the ink composition contains up to a total of 20% by mass of humectant, based on the total mass of the composition.

[0189] <Preservative> The ink composition and / or the printed deposit may further contain a preservative. The preservative may be an antioxidant or an anti-aging agent.

[0190] Suitable preservatives include sodium benzoate, benzoic acid, sorbic acid, potassium sorbate, calcium sorbate, calcium benzoate, methyl paraben, and mixtures of two or more thereof.

[0191] The ink composition may contain up to 2% by mass of the preservative, based on the total mass of the composition. More preferably, the ink composition contains up to 1% by mass of the preservative, based on the total mass of the composition.

[0192] <Surfactant> The ink composition and / or the printed deposit may further contain a surfactant.

[0193] Suitable surfactants include anionic, cationic, or nonionic surfactants, and mixtures of two or more thereof. Non-limiting examples of anionic surfactants include alkyl sulfates, alkyl aryl sulfonates, dialkyl sulfonates, dialkyl sulfosuccinates, alkyl phosphates, and polyoxyethylene alkyl ether sulfates. Non-limiting examples of cationic surfactants include alkyl amine salts, ammonium salts, alkyl pyridinium salts, and alkyl imidazolium salts. Non-limiting examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl aryl ethers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, glycerin fatty acid esters, fluorine-containing nonionic surfactants, and silicon-containing nonionic surfactants. Mixtures of two or more surfactants may be used.

[0194] The ink composition may contain up to 5% by mass of a surfactant, based on the total mass of the composition. More preferably, the ink composition contains up to 1% by mass of a surfactant, based on the total mass of the composition.

[0195] <Adhesion promoter> The ink composition and the printed deposit may further contain an adhesion promoter.

[0196] In some cases, the adhesion promoter can be a binder. Preferably, when the adhesion promoter is a binder, it is used in combination with a co-binder. In some cases, the adhesion promoter is a non-film-forming polymer. In some cases, the adhesion promoter can be used in combination with other polymers to produce the desired properties.

[0197] Suitable adhesion promoters include resins such as rosin, terpene, and modified terpene, aliphatic, alicyclic, and aromatic resins, terpene phenol resins, and silicone or mineral oil. Preferably, the adhesion promoter is an ester of terpene phenol resin and / or hydrogenated rosin.

[0198] The ink composition may contain 0.3 to 10% by mass of an adhesion promoter, based on the total mass of the composition. More preferably, the ink composition contains 1 to 5% by mass of an adhesion promoter, based on the total mass of the composition.

[0199] <Adhesion promoter> The ink composition and the printed deposit may further contain an adhesion promoter.

[0200] An adhesion promoter is a substance that acts to promote the adhesion of the ink composition to the substrate.

[0201] Suitable adhesion promoters are titanium phosphate complexes, titanium acetylacetonate, triethanolamine zirconate, zirconium citrate, zirconium propionate, organosilicon, polyketone binders, polyester binders, or ketone condensation resins.

[0202] <Dispersant> The ink composition and the printed deposit may further contain a pigment dispersant.

[0203] A dispersant is a substance that promotes the dispersion of the components of an ink composition, for example, it promotes the dispersion of pigments.

[0204] Suitable dispersants include ionic and nonionic dispersants. Preferably, the dispersant is an acrylic block copolymer.

[0205] The dispersant may be premixed with a colorant, such as a pigment.

[0206] The dispersant can be selected according to the properties of the colorant. The amount of the dispersant is preferably 2% to 200% by mass based on the mass of the pigment in the ink composition.

[0207] <Definition> As used herein, the term "printed deposit" refers to an ink composition that has been printed on a suitable substrate and cured. It is the ink composition of the present invention in which at least a part of the monomers present in the ink composition has been polymerized to form a film.

[0208] As used herein, the term "ink composition" includes ink compositions suitable for use in any type of printing, such as inkjet printing. The ink composition is typically in liquid form.

[0209] As used herein, the term "polymer" refers to any substance having repeating units.

[0210] <Other options> Each and every suitable combination of the above-described embodiments is expressly disclosed herein as if each and every combination was individually and explicitly recited.

[0211] Various further aspects and embodiments of the present invention will be apparent to those skilled in the art in view of the disclosure herein.

[0212] As used herein, "and / or" shall be construed as a specific disclosure of each of two particular features or components, whether or not the other is present. For example, "A and / or B" shall be construed as (i) A, (ii) B, and (iii) a specific disclosure of both A and B, as if each was individually recited herein.

[0213] Unless the context otherwise indicates, the above descriptions and definitions of features are not limited to a particular aspect or embodiment of the invention, but apply equally to all aspects and embodiments described.

[0214] Here, specific aspects and embodiments of the present invention will be described by way of example with reference to the above-described drawings.

[0215] <References> Fleischmann, C.; Lievenbrueck, M.; Ritter, H., Polymers (Basel), 2015, 7 (4), 717 Dollendorf, C.; Kreth, S. K.; Choi, S. W.; Ritter, H. Beilstein, J. Org. Chem. 2013, 9 (1), 453 Afsharnia, A.; Zabarjad, S. N.; Baradaran, R. S.; Bayat, M.; et al., J. Appl. Chem. Res., 2011, 18 (0), 13 McCurdy, K. G.; Laidler, K. J., Can. J. Chem., 1964, 42 (4), 825 U.S. Patent No. 7,030,244 U.S. Patent No. 6,870,063

Examples

[0216] The following non-limiting examples further illustrate the present invention.

[0217] Unless otherwise specified, all commercially available chemical substances were used as purchased from the supplier.

[0218] 1-Chloroanthraquinone, 1,5-anthraquinone, and 1,8-anthraquinone were purchased from Tokyo Chemical Industry Co., Ltd.

[0219] Propanolamine and methacryloyl chloride were purchased from Sigma-Aldrich.

[0220] All solvents were purchased from Fisher Scientific.

[0221] UV-vis spectroscopy was performed using a Shimadzu UV-1800 spectrophotometer with a suitable solvent as a reference.

[0222] FT-IR spectroscopy was performed using a Thermo Scientific Nicolet iS10 spectrophotometer with a SMART iTX attachment.

[0223] NMR spectra were obtained using a 500 MHz DCH Cryoprobe Spectrometer.

[0224] The viscosity of the solution was measured at 25 °C using a Brookfield DV-E viscometer at a spindle speed of 60 rpm.

[0225] The color space measurement was performed using an X-Rite eXact NGH spectrophotometer.

[0226] The curing of the acrylate / methacrylate film was carried out by placing the uncured sample on a 2 m slide under a Baldwin iron-doped mercury arc lamp (model CA300) and a Phoseon 20 W / cm 2 (at 395 nm) LED lamp (model FP300 225X20WC395). The standard curing conditions used were 60% arc lamp and 50% LED, and the slide was passed once under the lamp at a speed of 50 m / min. These curing conditions gave a UVA dose of approximately 175 mJ / cm 2 .

[0227] The aging test was carried out at 50 °C for the time indicated in the text using a Bandol Wheel (Unitronics Vision 120).

[0228] [Example 1 - Synthesis of Methacrylated Anthraquinone Compounds] Starting from commercially available chloroanthraquinones, five different methacrylated anthraquinones were synthesized. The reaction schemes for these syntheses are shown in Figure 1. In each case, the starting material chloroanthraquinone reacted with an appropriately functionalized amine to produce hydroxylated compounds 1 - 5. The hydroxyl groups were then functionalized with methacryloyl chloride to give compounds 1a - 5a. These structures were 1 confirmed by 1H NMR as detailed in the experimental section.

[0229] The UV-vis spectra of compounds 1a to 5a in solution are shown in Figure 2. The overall shape of the spectra is similar for each compound. As shown in Figure 3, the width of the strongest absorption and the subtle differences in λ max give rise to a change in the color of the substance.

[0230] Synthesis of 1-[(3-Hydroxypropyl)amino]anthracene-9,10-dione, 1

[0231] 1-Chloroanthraquinone (1 g, 4.1 mmol) was dissolved in 15 ml of NMP at 150 °C under a nitrogen atmosphere for 48 h with propanolamine (12.4 mmol, 0.93 g) to form a red solution. The reaction mixture was cooled to room temperature and then poured into water to precipitate the product, which was separated by filtration and recrystallized from acetonitrile. Yield: 0.95 g. 1 H NMR (500 MHz, d 6 -DMSO, δ): 9.7 (t, J = 6 Hz, 1H; NH), 8.2 (dd, J = 8 Hz, 2 Hz, 1H, Ar H), 8.1 (dd, J = 8 Hz, 2 Hz, 1H, Ar H), 7.9 (ddd, J = 8 Hz, 8 Hz, 2 Hz, 1H, Ar H), 7.8 (ddd, J = 7.8 Hz, 7.8 Hz, 2 Hz, 1H, Ar H), 7.6 (dd, J = 7.3 Hz, 9 Hz, 1H, Ar H), 7.4 (dd, J = 7 Hz, 1 Hz, 1H, Ar H), 7.3 (dd, J = 9 Hz, 1 Hz, 1H, Ar H), 4.6 (t, J = 5 Hz, 1H, OH), 3.6 (dt, J = 5 Hz, 6 Hz, 2H, CH2), 3.4 (td, J = 7 Hz, 6 Hz, 2H, CH2), 1.8 (tt, J = 6 Hz, 7 Hz, 2H, CH2). IR(ATR): ): ν = 3340 (br), 3271(s), 2930, 2866, 1662, 1626, 1592, 1571, 1510.

[0232] Synthesis of 3-[(9,10-dioxoanthracen-1-yl)amino]propyl 2-methylprop-2-enoate, 1a.

[0233] 1-[(3-Hydroxypropyl)amino]anthracene-9,10-dione (1 g, 2.9 mmol) was dissolved in 20 ml of THF together with triethylamine (1 ml, 7.5 mmol). The reaction mixture was cooled to 0 °C under nitrogen, and methacryloyl chloride (1 ml, 10.4 mmol) was added dropwise over 30 minutes. The mixture was stirred at 0 °C for 1 hour and then at room temperature for 18 hours. When the reaction was complete as determined by TLC (eluent: diethyl ether), the reaction mixture was poured into water to precipitate the red product, which was separated by filtration and then recrystallized from acetonitrile. Yield: 0.87 g of a red solid. 1 H NMR (500 MHz, CDCl 3 , δ): 9.8 (t, J = 5.7 Hz, 1H, NH), 8.3 (dd, J = 7.7, 1.6 Hz, 1H, Ar H), 8.2 (dd, J = 7.7, 1.6 Hz, 1H, Ar H), 7.8 (ddd, J = 7.5,7.5,1.5 Hz, 1H, Ar H), 7.7 (ddd, J = 7.6, 7.6, 1.5 Hz, 1H, Ar H), 7.6 (dd, J = 7.3, 1.4 Hz, 1H, Ar H), 7.5 (dd, J = 8.5, 7.3 Hz, 1H, Ar H), 7.0 (dd, J = 8.6, 1.3 Hz, 1H, Ar H), 6.1 (dq, J = 2, 0.9 Hz, 1H, C=CH), 5.6 (dq, J = 1.8, 1.8 Hz, 1H, C=CH), 4.3 (t, J = 6.2 Hz, 2H, CH2), 3.5 (dt, J = 5.6, 7.1 Hz, 2H, CH2), 2.2 (tt, J = 6.4, 7.0 Hz, 2H, CH2), 1.9 (dd, J = 1.7, 0.9 Hz, 3H, CH3). UV-vis (THF): λ max = 501 nm. IR(ATR): 3270, 2881, 1717(s), 1661, 1628. 1592, 1573, 1507.

[0234] Synthesis of 1,5-bis[(3-hydroxypropyl)amino]anthracene-9,10-dione, 2

[0235] 1,5-Dichloroanthraquinone (5 g, 18 mmol) was dissolved in 100 ml of NMP, and propanolamine (8.3 ml, 108 mmol) and disodium phosphate (10.25 g, 72 mmol) were added. The mixture was heated at 150 °C for 48 h under nitrogen and then cooled to room temperature. The reaction mixture was poured into water to precipitate the product, which was separated by filtration. The product was redissolved in a small amount of DMSO, water was added to precipitate it, and then it was separated by filtration and washed with a small amount of methanol. Yield: 4.2 g. 1 H NMR (500 MHz, d 6 -DMSO, δ): 9.7 (t, J = 5.8, 2H, NH), 7.6 (dd, J = 7.6, 8.0, 2H, Ar H), 7.4 (dd, J = 7.5, 1.2, 2H, Ar H), 7.1 (dd, J = 8.8, 1.0, 2H, Ar H), 4.6 (s, 2H, OH), 3.6 (t, J = 6.8, 4H, CH 2 ), 3.4 (dt, J = 5.9, 6.9, 4H, CH 2 ), 1.8 (tt, J = 6.5, 6.7, 4H, CH 2 ). IR(ATR): 3355(br), 3266, 2925, 2867, 1668, 1617, 1597, 1569, 1504.

[0236] Synthesis of 3-{[5-({3-[(2-methylprop-2-enoyl)oxy]propyl}amino)-9,10-dioxoanthracen-1-yl]amino}propyl 2-methylprop-2-enoate, 2a

[0237] 1,5-Bis[(3-hydroxypropyl)amino]anthracene-9,10-dione (1 g, 2.8 mmol) was dissolved in 8 ml of DMF. TEA (2 ml, 15 mmol) was added and the reaction mixture was cooled to 0 °C under nitrogen. Methacryloyl chloride (1.1 ml, 11.3 mmol) was added dropwise over 30 minutes. The mixture was stirred at 0 °C for 30 minutes and then at room temperature overnight. 50 ml of water was added and the product was extracted into dichloromethane. The organic layer was washed twice with brine and then dried over MgSO 4 4. The volatile substances were then removed under reduced pressure and the product was recrystallized from acetonitrile. Yield: 1.03 g. 1 H NMR (500 MHz, CDCl 3 3, δ): 9.8 (t, J = 6 Hz, 2H, NH), 7.5 (m, 4H, Ar H), 6.9 (dd, J = 8.5, 1.7 Hz, 2H, Ar H), 6.1 (dq, J = 1.9, 0.9 Hz, 2H, C=CH), 5.6 (dq, J = 1.7, 3 Hz, 2H, C=CH), 4.3 (t, J = 6.2 Hz, 4H, CH 2 2), 3.4 (dt, J = 5.8, 7.3 Hz, 4H, CH 2 2), 2.1 (tt, J = 6.5, 6.7 Hz, 4H, CH 2 2), 1.9 (m, 6H, CH 3 3). UV-vis (THF): λmax = 513 nm. IR(ATR): 3275, 2872, 1707, 1619, 1598, 1570, 1503.

[0238] Synthesis of 1,5-bis[(4-hydroxyphenyl)amino]-4a,9a-dihydroanthracene-9,10-dione, 3

[0239] 1,5-Dichloroanthraquinone (5 g, 18 mmol) was dissolved in NMP under nitrogen. 4-Hydroxyaniline (11.8 g, 108 mmol) and disodium phosphate (10.25 g, 72 mmol) were added, and the mixture was heated at 150 °C overnight. When the reaction was complete, the mixture was poured into water to precipitate the product, which was separated by filtration and recrystallized from MEK. Yield: 4.8 g of purple solid. 1 H NMR (500 MHz, d 6 -DMSO, δ): 11.1 (s, 2H, NH), 9.5 (s, 2H, OH), 7.55 (m, 4H, Ar H), 7.2 (dd, J = 8.2, 1.8 Hz, 2H, Ar H), 7.15 (d, J = 9.2 Hz, 4H, Ar H), 6.8 (d, J = 8.8 Hz, 4H, Ar H). IR (ATR): ν = 3120 (br), 3078 (s), 2805 (w), 1617 (w), 1588.9 (str), 1512 (s).

[0240] Synthesis of 4-{[5-({4-[(2-Methylprop-2-enoyl)oxy]phenyl}amino)-9,10-dioxoanthracen-1-yl]amino}phenyl 2-methylprop-2-enoate, 3a

[0241] 1,5-Bis[(4-hydroxyphenyl)amino]-4a,9a-dihydroanthracene-9,10-dione (1 g, 2.4 mmol) was dissolved in THF under nitrogen. TEA (2 ml, 15 mmol) was added, and the mixture was cooled to 0 °C under nitrogen. Methacryloyl chloride (1 ml, 10.3 mmol) was added dropwise, and the mixture was stirred at 0 °C for 1 h and then at room temperature overnight. Next, the mixture was poured into water to precipitate a purple solid, which was recrystallized from methanol. Yield: 0.97 g. 1 H NMR (500 MHz, CDCl 3, δ): 11.3 (s, 2H, NH), 7.7 (dd, J = 7.4, 1.3 Hz, 2H, Ar H), 7.5 (dd, J = 7.5, 8.8 Hz, 2H, Ar H), 7.4 (dd, J = 8.8, 1.4 Hz, 2H, Ar H), 7.3 (d, J = 9.1 Hz, 4H, Ar H), 7.2 (d, J = 8.9 Hz, 4H, Ar H), 6.4 (m, 2H, C=CH), 5.8 (m, 2H, C=CH), 2.1 (m, 6H, CH 3 ). UV-vis (THF): λmax = 523 nm. IR(ATR): ν = 3067, 2980, 1733, 1695, 1627.

[0242] Synthesis of 1,8-bis[(3-hydroxypropyl)amino]anthracene-9,10-dione, 4

[0243] 1,8-Dichloroanthraquinone (5 g, 18 mmol) was dissolved in 100 ml of NMP, and propanolamine (8.3 ml, 108 mmol) and disodium phosphate (10.25 g, 72 mmol) were added. The mixture was heated at 150 °C for 48 h under nitrogen and then cooled to room temperature. The reaction mixture was poured into water to precipitate the product, which was separated by filtration. The product was purified by column chromatography (silica gel, eluent 1:1 diethyl ether:petroleum ether) to give 3.8 g of a dark purple solid. 1 H NMR (500 MHz, d 6 -DMSO, δ): 9.5 (t, J = 6.5 Hz, 2H, NH), 7.5 (dd, J = 9, 7.6 Hz, 2H, Ar H), 7.3 (dd, 7.4, 1.2 Hz, 2H, Ar H), 7.2 (dd, J = 8.9, 1.0 Hz, 2H, Ar H), 4.6 (t, J = 5.5 Hz, 2H, OH), 3.6 (dt, J = 5.6, 5.4 Hz, 4H, CH 2 ), 3.4 (dt, J = 6.4, 5.8 Hz, 4H, CH2 ), 1.8 (tt, J = 6.6, 7.0 Hz, 4H, CH 2 ). IR(ATR): ν = 3506, 3310(br), 3261, 2925, 2851, 1650 (s), 1613, 1564, 1503.

[0244] Synthesis of 3-{[8-({3-[(2-methylprop-2-enoyl)oxy]propyl}amino)-9,10-dioxoanthracen-1-yl]amino}propyl 2-methylprop-2-enoate, 4a

[0245] 1,8-Bis[(3-hydroxypropyl)amino]anthracene-9,10-dione (1 g, 2.8 mmol) was dissolved in 8 ml of DMF together with triethylamine (2 ml, 15 mmol). The reaction mixture was cooled to 0 °C under nitrogen, and methacryloyl chloride (1 ml, 10.4 mmol) was added dropwise over 30 minutes. The mixture was stirred at 0 °C for 1 hour and then at room temperature for 2 hours. The reaction mixture was poured into water to precipitate the product, which was separated by filtration. Yield: 1.2 g of a dark purple solid. 1 H NMR (500 MHz, CDCl 3 , δ): 9.6 (t, J = 5.9 Hz, 2H, NH), 7.5 (dd, J = 7.3, 1.2 Hz, 2H, Ar H), 7.4 (dd, J = 8.8, 7.6 Hz, 2H, Ar H), 7.0 (dd, J = 8.8, 1.3 Hz, 2H, Ar H), 6.1 (m, 2H, C=CH), 5.6 (m, 2H, C=CH), 4.3 (t, J = 6.5 Hz, 4H, CH 2 ), 3.5 (dt, J = 7.3, 5.6 Hz, 4H, CH 2 ), 2.2 (tt, J = 6.9, 7.0 Hz, 4H, CH 2 ), 2.0 (m, 6H, CH 3 ). UV-vis (THF): λ max= 542 nm. IR (ATR): ν = 3273, 2952, 1710, 1656, 1615, 1567.

[0246] Synthesis of 1,8-bis[(4-hydroxyphenyl)amino]anthracene-9,10-dione, 5

[0247] 1,8-Dichloroanthraquinone (5 g, 18 mmol) was dissolved in DMSO together with disodium phosphate (10.25 g, 72 mmol) and 4-hydroxyaniline (11.8 g, 108 mmol). The mixture was heated at 150 °C for 48 h, then cooled and poured into water to precipitate the product. The product was purified by column chromatography (silica gel, eluent petroleum ether:diethyl ether 1:1). Yield: 5.1 g of a purple solid. 1 H NMR (500 MHz, d 6 -DMSO, δ): 10.9 (s, 2H, NH), 9.5 (s, 2H, OH), 7.5 (dd, J = 7.5, 8.4, 2H, Ar H), 7.4 (dd, J = 7.4, 1.6, 2H, Ar H), 7.2 (dd, J = 8.5, 1.5, 2H, Ar H), 7.1 (d, J = 9.2 Hz, 4H, Ar H), 6.8 (d, J = 9.2 Hz, 4H, Ar H). IR (ATR): ν = 3233 (br), 1649, 1617, 1599, 1562, 1511.

[0248] Synthesis of 4-{[8-({4-[(2-methylprop-2-enoyl)oxy]phenyl}amino)-9,10-dioxoanthracen-1-yl]amino}phenyl 2-methylprop-2-enoate, 5a

[0249] 1,8-Bis[(4-hydroxyphenyl)amino]anthracene-9,10-dione (1 g, 2.4 mmol) was dissolved in 8 ml of DMF. TEA (2 ml, 15 mmol) was added and the mixture was cooled to 0 °C under nitrogen. Methacryloyl chloride (1 ml, 10.3 mmol) was added dropwise over 30 minutes and the mixture was stirred at 0 °C for 30 minutes and then at room temperature overnight. The mixture was then poured into water to precipitate the product, which was separated by filtration and recrystallized from methanol. 1 H NMR (500 MHz, CDCl 3 , δ): 11.2 (s, 2H, NH), 7.7 (dd, J=7.0, 1.9 Hz, 2H, Ar H), 7.5 (dd, J=8.9, 1.9 Hz, 2H, Ar H), 7.4 (dd, J=6.9, 8.9 Hz, 2H, Ar H), 7.3 (d, J=9.3 Hz, 4H, Ar H), 7.2 (d, J=9 Hz, 4H, Ar H), 6.4 (m, 2H, C=CH), 5.8 (m, 2H, C=CH), 2.0 (m, 6H, CH 3 )。UV-vis (THF): λ max = 544 nm。IR(ATR): ν =3217, 2928, 1732, 1616, 1598, 1569, 1508。

[0250] [Example 2 - Incorporation into Crosslinked Film] The methacrylate-functionalized dye compounds 1a to 5a were dissolved in a carrier monomer and optionally further solvent.

[0251] Dipropylene glycol diacrylate (DPGDA) was used as the carrier monomer.

[0252] The stock solution was formed from DPGDA and contained 2,4,6-trimethylbenzoyl diphenylphosphine oxide (Omnirad TPO) at 10% w / w and benzophenone at 5% w / w.

[0253] The ink solution of the present invention was prepared by mixing the above stock solution with Compound 1a, 3a, 4a, or 5a. These are referred to as Solution 1a, 3a, 4a, and 5a, respectively.

[0254] Compound 4a and 5a were dissolved in DPGDA at 5% by mass. Compounds 1a and 3a were dissolved in DPGDA at 5% by mass using 5% by mass of dichloromethane.

[0255] The comparative solutions were prepared using hydroxylated anthraquinone compounds 1, 3, 4, and 5, and are referred to as Comparative Solution 1, 3, 4, and 5, respectively. Compounds 4 and 5 were dissolved in DPGDA at 5% by mass. Compounds 1 and 3 were dissolved in DPGDA at 5% by mass using 5% by mass of dichloromethane.

[0256] A further comparative solution was made by dissolving methacrylated anthraquinone 4a in DCM. This solution is referred to as Comparative Solution 4-1. The composition of the solution was 2% by mass of Compound 4a dissolved in DCM, 10% by mass of Omnirad TPO, and 5% by mass of benzoquinone.

[0257] [Example 3 - Color Fastness Test] Films of Solution 1a, 3a, 4a, and 5a prepared in Example 2 were prepared on a coated substrate (gloss card). Next, these films were irradiated with UV. Curing of the films was carried out by placing uncured samples on a 2 m slider under a Baldwin iron-doped mercury arc lamp (model CA300) and a Phoseon 20W / cm 2 at 395 nm and a Phoseon 20W / cm 2 LED lamp (model FP300 225X20WC395). Under standard curing conditions, the arc lamp was set to 60% and the LED lamp was set to 50%, and the slider was passed once under the lamp at a speed of 50 m / min. These curing conditions provide a UVA dose of approximately 175 mJ / cm 2 .

[0258] The first and second rows of the photograph in Fig. 4(a) show the colors of these films before and after UV irradiation, respectively. The methacrylated dyes change during this curing process, but they retain their dark colors.

[0259] As a control test, these films were compared with films produced using Comparative Solutions 1, 3, 4, 4-1, and 5.

[0260] The third and fourth rows of the photograph in Fig. 4(a) show the films of Comparative Solutions 1, 3, 4, and 5 before and after UV curing, respectively. These films lose most of their color and mostly turn brown. It is proposed that the binding to the polymer network stabilizes the dye.

[0261] The results of Comparative Example 4-1 are shown in Fig. 4(b). The first row shows the film of Comparative Solution 4-1 before UV curing. The second row shows the film of Comparative Solution 4-1 after UV curing. The left column shows the film printed on an uncoated porous card, and the right column shows the film coated on a glossy card. The color of the film after UV curing is much browner than the film after UV curing produced using Solution 4a. The film on the glossy card shows increased adhesiveness compared to any of the films produced using Solutions 1a, 3a, 4a, and 5a.

[0262] From the images in Fig. 4, it is clear that the methacrylated dye films retain their color even though it changes, and it is clear that the non-methacrylated films are significantly decolorized.

[0263] To test this result quantitatively, the color of the films was described using an X-Rite spectrophotometer. This device analyzes the light reflected from the substrate and gives results from the perspective of a well-understood color space. The CIELAB color space was used for these tests, and within this color space each color has three coordinates, L * ("lightness"), a *and b * (These are each described by their position on the green - red and blue - yellow color axes).

[0264] The CIELAB space was originally designed to correspond to perceptual uniformity (i.e., changes in CIELAB coordinates are directly correlated with visually perceived changes). This model enables the quantification of the color difference (ΔE) between two surfaces using Equation (1), where L 1 * , a 1 * , b 1 * represents the color of the first surface, and L 2 * , a 2 * , b 2 * represents the color of the second surface. [Equation]

[0265] For the film shown in Figure 4(a), the difference between the film before UV irradiation and the film after UV irradiation was measured and calculated. The results are summarized in Figure 5 and Table 1 below.

[0266] [Table 1]

[0267] The values for each pair "(i)" and "(ii)" in the table (and in Figure 5) show the changes during irradiation for Solutions 1a, 3a, 4a, and 5a, and Comparative Solutions 1, 3, 4, and 5. From these data, it is clear that the color change is greater for the hydroxy - functionalized dyes (Comparative Solutions 1, 3, 4, and 5), indicating that these dyes are decomposing faster under UV irradiation.

[0268] [Example 4 - Aging] To further test how the film degrades when exposed to UV, the cured film was placed in a 50 °C Bandol Wheel. This device is designed to accelerate the aging of the sample by exposing the sample to an amount of ultraviolet radiation equal to approximately twice that of natural UV from the sun.

[0269] Figure 6 shows the ΔE of each film as it changes over time as the film ages. "Line 1a" refers to the film produced using solution 1a, "line 1" refers to the film produced using comparative solution 1, and so on.

[0270] In all cases other than 5 / 5a, the films containing hydroxylated dyes continue to increase ΔE more rapidly than the films containing methacrylated dyes.

[0271] [Example 5 - Test of Dye Binding] To test whether color leaches from the cured film, the cured film was immersed in a solvent.

[0272] An uncoated glossy card was coated with a film produced by curing a solution containing methacrylate dye 4a (i.e., solution 4a).

[0273] Four 1 cm 2 pieces were cut from this film-coated substrate and cured for various curing times (the curing time increases from photo a to d; film a was passed under the lamp once, film b twice, film c three times, and film d four times). The color of the film remained purple during curing for all curing times.

[0274] Each of the four pieces was immersed in 5 ml of acetone in a separate container for 24 hours. In all cases, the acetone remained colorless and the substrate remained purple during this process.

[0275] A non-coated glossy card was coated with a film produced by curing a solution containing hydroxylated dye 4 (i.e., comparative solution 4). Four 1 cm pieces were cut from this film-coated substrate and cured for the same time as the methacrylated film (the curing time increases from e to h; film e was passed under the lamp once, film f twice, film g three times, and film h four times). In this case, the color of the film changes to brown during curing. 2 Each of the four pieces was immersed in 5 ml of acetone in a separate container for 24 hours. The acetone used for the immersion turned bright pink in all cases.

[0276]

[0277] From these results, we present that the methacrylated dye is covalently bonded to the film, while the hydroxylated dye is not.

[0278] Furthermore, the methacrylated dye film is relatively stable under UV curing, while the hydroxylated dye film immediately turns brown. However, the dye leaching from the hydroxylated dye film remains pink. We suggest that the brown coloring may be a surface degradation effect and that sufficient pink dye remains in the film to color the immersion liquid. Similar results were obtained when the immersion liquid was dichloromethane.

[0279] Figure 7 shows the effect of immersion on two coated substrates. From the image, it is clearly seen that the color of the cured film changes more significantly for the hydroxylated film than for the corresponding methacrylated film during curing. Furthermore, the dye leaches more significantly and more easily from the film containing the hydroxylated dye than from the film containing the methacrylated dye. From these results, the methacrylated dye seems to be strongly bonded in the cured film.

[0280] [Example 6 - Viscosity] The viscosity of the stock solution produced in Example 2 was measured to be 11.5 mPa·s at 25°C.

[0281] Two further compositions of the present invention were prepared by mixing 1% by weight and 5% by weight of Compound 4a, respectively, with the above stock solution.

[0282] The viscosities of the respective compositions of the present invention, measured at 25°C, were 11.3 mPa·s (1% by weight of 4a) and 11.7 mPa·s (4% by weight of 4a), respectively.

[0283] From this, it seems that the dye monomer compound does not significantly contribute to the viscosity of the ink composition.

[0284] [Example 7 - Printing] Using a Fujifilm Dimatix inkjet (model number DMP - 2831) printer, a logo was printed from a solution in which 2% w / w of 4a was dissolved in the stock solution described in Example 2.

[0285] Figure 8(a) is a photograph of the obtained logo printed on paper. Figure 8(b) shows the same logo after exposure to UV irradiation. The image quality and curing of the printed deposit are good. When a drop of MEK was dripped, the ink did not visibly flow.

[0286] These results demonstrate that the compositions presently claimed form an ink that is practicable for inkjet printing and UV curing.

Claims

1. A curable inkjet ink composition comprising a dye monomer, a carrier monomer, and an initiator, wherein the dye monomer has a chromophore moiety covalently bonded to two or more polymerizable functional groups, and the dye monomer is present in an amount of 1.0% by mass or more based on the total mass of the ink composition; and the carrier monomer has at least one polymerizable functional group and is present in an amount of 50% by mass or more based on the total mass of the ink composition, The curable inkjet ink composition having a viscosity of 0.5 to 30 mPa·s at 25°C.

2. The curable inkjet ink composition according to claim 1, wherein the chromophore moiety is a chemical group that imparts color to the dye monomer.

3. The curable inkjet ink composition according to claim 1 or 2, wherein the chromophore moiety is selected from anthraquinone, anthrapyridone, anthrapyrimidine, anthrapyrimidone, isothiazoloanthrone, azo dyes, bisazo dyes, methine, bis-methine, coumarin, 3-aryl-2,5-dioxypyrroline, 3-aryl-5-dicyanomethylene-2-oxypyrroline, perinone, quinophthalone, phthalocyanine, metal phthalocyanine, nitroarylamine, and 2,5-diarylaminoterephthalic acid ester.

4. The curable inkjet ink composition according to any one of claims 1 to 3, wherein the chromophore moiety is anthraquinone.

5. The curable inkjet ink composition according to any one of claims 1 to 4, substantially free of pigments.

6. The curable inkjet ink composition according to any one of claims 1 to 5, wherein the dye monomer is present in an amount of 30% by weight or less based on the total mass of the ink composition.

7. The curable inkjet ink composition according to any one of claims 1 to 6, wherein the two or more polymerizable functional groups of the dye monomer are independently selected from alkenyl, alkynyl, acrylate, methacrylate, maleate, fumarate, and acrylamide functional groups.

8. The curable inkjet ink composition according to claim 7, wherein the two or more polymerizable functional groups of the dye monomer are methacrylate.

9. The curable inkjet ink composition according to claim 1, wherein the dye monomer is bifunctional.

10. The curable inkjet ink composition according to any one of claims 1 to 9, wherein the carrier monomer is a single monomer.

11. The curable inkjet ink composition according to any one of claims 1 to 9, wherein the carrier monomer is a mixture of two or more monomers.

12. The curable inkjet ink composition according to any one of claims 1 to 11, wherein the carrier monomer is polyfunctional.

13. The curable inkjet ink composition according to any one of claims 1 to 12, wherein at least one polymerizable functional group of the carrier monomer is selected from alkenyl, alkynyl, acrylate, methacrylate, maleate, fumarate, and acrylamide functional groups.

14. The curable inkjet ink composition according to claim 13, wherein at least one polymerizable functional group of the carrier monomer is acrylate.

15. The curable inkjet ink composition according to claim 14, wherein the carrier monomer is bifunctional.

16. The curable inkjet ink composition according to any one of claims 1 to 15, wherein the initiator is a photoinitiator.

17. An ink container containing the curable inkjet ink composition according to any one of claims 1 to 16.

18. A printing method comprising the steps of preparing an ink container containing the curable inkjet ink composition according to any one of claims 1 to 16, directing a flow of droplets of the curable inkjet ink composition towards a substrate, and curing the printed inkjet ink composition.

19. The method according to claim 18, wherein the step of curing the printed inkjet ink composition comprises treating the printed inkjet ink composition with UV radiation.

20. The method according to claim 19, wherein the printed inkjet ink composition is treated by application of a plurality of UV radiations.

21. A substrate comprising a printed deposit produced by the method according to any one of claims 18 to 20.

22. A printed deposit comprising a cured polymer film formed by curing the curable inkjet ink composition according to any one of claims 1 to 16.

Images