WO2019226645A1

WO2019226645A1 - Hybrid inks including uv monomers, oligomers, and resins

Info

Publication number: WO2019226645A1
Application number: PCT/US2019/033305
Authority: WO
Inventors: Sean Michael BUONO; Shih-yu FENG; Ruei-Ming Huang; Yung-Hsien Lu; Kun Hung Tu; Yu-Hsien Wu
Original assignee: Corning Incorporated
Priority date: 2018-05-25
Filing date: 2019-05-21
Publication date: 2019-11-28
Also published as: TW202006075A

Abstract

Printing compositions described herein include a colorant, at least one light-activated monomer, at least one oligomer, at least one resin, and a photoinitiator. The at least one resin is selected from the group consisting of epoxy resins, amino resins, and silicone resins. Also described are methods of printing on a substrate having at least a portion that is non-planar with respect to a central portion of the substrate. Such methods include jetting, onto the substrate, a printing composition to form a printed substrate, exposing the printed substrate to a light source to at least partially cure the printing composition, and heating the printed substrate to cure the printing composition after exposing the printed substrate to the light source.

Description

HYBRID INKS INCLUDING UV MONOMERS, OLIGOMERS, AND RESINS

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority under 35 U.S.C. § 119 of U.S.

Provisional Application Serial No. 62/676414 filed on May 25, 2018, the content of which is relied upon and incorporated herein by reference in its entirety.

BACKGROUND

FIELD

[0002] The present specification generally relates to inkjet inks and, more particularly, to ultraviolet (UV) and thermally curable hybrid inkjet inks including UV monomers, oligomers, and resins.

TECHNICAL BACKGROUND

[0003] Decoration of substrates is desired for both aesthetic and functional purposes. In the consumer electronics industry, for example, there is a growing demand for three- dimensional (3D) substrates (e.g., curved substrates) and the demand for glass decoration has also grown. However, conventional decoration technologies have limitations when applied to 3D substrates.

[0004] Accordingly, alternative methods and inks for glass decorating are needed that are suitable for use with 3D substrates.

SUMMARY

[0005] According to one embodiment, a printing composition includes a colorant, at least one light-activated monomer, at least one oligomer, at least one resin, and a photoinitiator. The at least one resin is selected from the group consisting of epoxy resins, amino resins, and silicone resins.

[0006] According to another embodiment, a method of printing on a substrate having at least a portion that is non-planar includes jetting, onto the substrate, a printing composition to form a printed substrate. The printing composition includes a colorant, at least one light- activated monomer, at least one oligomer, at least one resin, and a photoinitiator. The at least one resin is selected from the group consisting of epoxy resins, amino resins, and silicone resins. The method also includes exposing the printed substrate to a light source to at least partially cure the printing composition and heating the printed substrate to cure the printing composition after exposing the printed substrate to the light source.

[0007] According to another embodiment, a printed substrate includes a substrate having at least a portion that is non-planar and a cured image formed on the substrate. The cured image includes a colorant and a polymer formed from at least one light-activated monomer, at least one oligomer, and at least one resin selected from the group consisting of epoxy resins, amino resins, and silicone resins.

[0008] Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments described herein, including the detailed description which follows, the claims, as well as the appended drawings.

[0009] It is to be understood that both the foregoing general description and the following detailed description describe various embodiments of printing compositions, methods of printing on substrates, and printed substrates and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments, and are incorporated into and constitute a part of this specification. The drawings illustrate the various embodiments described herein, and together with the description serve to explain the principles and operations of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 is a perspective view of a printed substrate having one edge that is non- planar with respect to a central portion of the substrate in accordance with one or more embodiments described herein;

[0011] FIG. 2 is a cross-sectional view of the printed substrate of FIG. 1 in accordance with one or more embodiments described herein; [0012] FIG. 3 is a cross-sectional view of a printed substrate having two edges are non- planar with respect to a central portion of the substrate in accordance with one or more embodiments described herein;

[0013] FIG. 4 is a perspective view of a printed substrate having four edges that are non- planar with respect to a central portion of the substrate in accordance with one or more embodiments described herein; and

[0014] FIG. 5 shows a thermal desorption gas chromatogram mass spectroscopy (GC/MS) spectrum of a divinyl-hexamethyl-octasila-silsesquioxane resin component in accordance with one or more embodiments described herein.

DETAILED DESCRIPTION

[0015] Reference will now be made in detail to various embodiments of printing compositions, methods of printing on substrates using printing compositions, and printed substrates, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts.

[0016] In general, described herein are hybrid printing compositions that are both thermally curable and photocurable so that a printed image with a substantially uniform thickness may be formed on a substrate (for example a substrate with a non-planar surface). As used herein, thermally curable refers to a material that cures based on expose to increased temperature. As used herein, photocurable refers to a material that cures based on exposure to light, for example, but not limited to, ultraviolet light. In some embodiments, the hybrid printing compositions are inkjet printable as inkjet printing provides an ability to print not only on 2D substrates (where both major surfaces are substantially planar), but also on 3D- shaped and 2.5D-shaped substrates. Printing on 3D-shaped and 2.5D-shaped substrate is not easily achieved or not possible with other printing techniques such as screen printing. Screen printing relies on the use of a screen where ink is applied to the substrate by squeezing the ink through openings in the screen with a squeegee. The screen needs to be in full contact with the substrate in order to perform the screen printing process, which results in limited or no capability for some 3D-shaped and 2.5D-shaped substrates. On the other hand, inkjet printing does not require the printhead to contact the substrate, but rather that the printhead be perpendicular to the substrate surface. “3D-shaped” substrates include substrates where both major surfaces of the substrate have curvature, for example at one or more edges of the substrate.“2.5D-shaped” substrates include substrates where only one major surface has curvature, for example at one or more edges of the substrate. In some embodiments, a substrate may have 4 edges and the substrate may have curvature at 1, 2, 3, or all 4 edges. The substrate surfaces upon which the printing composition may be printed include, but is not limited to, a glass surface, a glass-ceramic surface, a ceramic surface, a metal oxide surface, a metal surface, a polymeric surface, or similar surfaces.

[0017] The printing compositions described herein include at least one light-activated monomer, at least one oligomer, and at least one resin selected from the group consisting of epoxy resins, amino resins, and silicone resins. The printing compositions are hybrid ink compositions that are curable by photocuring and thermal curing processes. Accordingly, the printing compositions can be applied to substrates having non-planar portions, at least partially cured by photocuring (for example exposure to ultraviolet light) to adhere the printing composition to the substrate, and thermally cured to fully cure the image formed by the printing composition. In some embodiments, photocuring the printing composition may reduce or even eliminate dripping or running of the ink on non-planar surfaces of the substrate, enabling 3D substrates to be decoratively printed in a reliable manner. Various embodiments of printing compositions, methods of printing on substrates, and printed substrates will be described herein with specific reference to the appended drawings.

[0018] Directional terms as used herein - for example up, down, right, left, front, back, top, bottom, vertical, horizontal - are made only with reference to the figures as drawn and are not intended to imply absolute orientation unless otherwise expressly stated.

[0019] Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order, nor that with any apparatus specific orientations be required. Accordingly, where a method claim does not actually recite an order to be followed by its steps, or that any apparatus claim does not actually recite an order or orientation to individual components, or it is not otherwise specifically stated in the claims or description that the steps are to be limited to a specific order, or that a specific order or orientation to components of an apparatus is not recited, it is in no way intended that an order or orientation be inferred, in any respect. This holds for any possible non-express basis for interpretation, including: matters of logic with respect to arrangement of steps, operational flow, order of components, or orientation of components; plain meaning derived from grammatical organization or punctuation, and; the number or type of embodiments described in the specification.

[0020] As used herein, the singular forms“a,”“an” and“the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to“a” component includes aspects having two or more such components, unless the context clearly indicates otherwise.

[0021] Referring to FIG. 1, a printed substrate 100 is shown. In the embodiment shown in FIG. 1, the printed substrate 100 includes a substrate 101 that has a three-dimensional shape. As used herein, the phrase“three-dimensional shape” means that the substrate 101 generally has a shape that, at least in part, deviates from planar. In various embodiments, the 3D substrate 101 has at least a portion that is curved and deviates from planar with respect to a central portion of the substrate. Accordingly, the substrate 101 includes a planar portion 102 and a non-planar portion 104 that is non-planar with respect to the planar portion 102 of the substrate and an image 106 printed on the substrate 101. For example and without limitation, the substrate 101 can have one of a number of three-dimensional shapes, such as a sled shape (depicted in FIG. 3) in which non-planar portions l04a, l04b curve away from a central portion, or a dish shape (depicted in FIG. 4) in which non-planar portions l04a, l04b, l04c, l04d curve away from a central portion. In various embodiments, the substrate 101 may also have a substantially planar portion 102, as shown in the cross-sectional views of the substrate 101 schematically depicted in FIGS. 2 and 3.

[0022] As can be seen in FIG. 2, the image 106 is printed on the planar portion 102 and the non-planar portion 104 of the substrate 101. Although depicted in FIGS. 1 and 2 as being printed on both the planar and non-planar portions of the substrate 101, it is contemplated that in some embodiments, the image 106 can be printed on just the planar portion 102 or just the non-planar portion 104 of the substrate 101.

[0023] The substrate 101 can be any suitable type of substrate, depending on the particular embodiment. Suitable substrates are those substrates that are able to withstand the photocuring and thermal curing described below without being adversely impacted. The substrate 101 may be any one of a variety of substrates, including but not limited to, glass, glass-ceramic, ceramic, metal oxide, metal or polymeric substrates. In some embodiments, the substrate 101 can be formed from chemically-strengthened or non-chemically- strengthened glass or glass-ceramic. For embodiments in which the substrate 101 is chemically-strengthened, an ion exchange process can be utilized which includes exchanging Na⁺, Li⁺, or Na⁺ and Li⁺ ions in the surface of the glass for large alkali ions. The ion- exchange can occur to a depth of approximately 40 pm from the surface of the glass substrate. Of course, the depth of ion-exchange can be greater or less than 40 pm. For example, some embodiments can include chemically strengthened glass having a relatively high surface compressive stress (CS), a relatively high depth of compressive layer (DOC), and/or moderate central tension (CT). The thicknesses of this glass can range from 0.3 mm to 2.1 mm or greater. Other embodiments can include thinner chemically strengthened or non-chemically strengthened glass. Such thicknesses can be less than 0.5 mm to 0.1 mm or thinner. It is also contemplated that the glass substrate can be a soda lime glass, an alkali-containing aluminosilicate glass, an alkali-containing aluminoborosilicate glass, an alkali-containing borosilicate glass, an alkali-containing glass-ceramic or other glasses known by those skilled in the art.

[0024] In the embodiment shown in FIGS. 1 and 2, the substrate 101 has one non-planar portion 104 in the form of a non-planar edge. However, as shown in FIG. 3, some embodiments may have two non-planar portions l04a, l04b, such as when the substrate has two non-planar edges (e.g., a“sled” shape). FIG. 4 depicts an embodiment in which the substrate 101 has a“dish” shape, and includes four non-planar portions l04a, l04b, l04c, and l04d. Other shapes for the substrate 101 are contemplated, such as shapes in which the non- planar portion of the substrate is a central portion of the substrate instead of or in addition to an edge.

[0025] As shown in FIGS. 1-3, in various embodiments, an image 106 is printed on the substrate 101, and in particular, on a non-planar portion 104 of the substrate 101. The image 106 can be printed on the substrate 101 using an ink jet printing method in which a printing composition is jetted, for example with an ink jet printer, onto the surface of the substrate 101, as will be described in greater detail below. [0026] In various embodiments, the printing composition includes a colorant, at least one light-activated monomer, at least one oligomer, at least one resin selected from the group consisting of epoxy resins, amino resins, and silicone resins, and a photoinitiator.

[0027] The colorant can be a pigment or a dye, depending on the particular embodiment, and is added to give the printing composition its color. In various embodiments, the printing composition has a cyan, a magenta, a yellow, or a black color, such as when the printing composition is used as part of a CMYK ink set. However, other colors are contemplated.

[0028] In embodiments in which the colorant is a pigment, the pigment can be, by way of example and not limitation, carbon black, iron pigment, cobalt pigment, cadmium pigment, chromium pigment, titanium pigment, zinc pigment, lead pigment, magnesium pigment, vanadium pigment, copper chromite black spinel, copper phthalocyanine, pigment yellow 17, pigment yellow 83, pigment yellow 93, pigment yellow 110, pigment yellow 150, pigment yellow 151, pigment yellow 180, pigment red 146, pigment red 184, pigment red 208, quiacridone red 122, quiacridone red 202, quiacridone violet 19, or combinations thereof. Other pigments known to those in the art may also be used, such as azo pigments, monoazo pigments, disazo pigments, azo pigment lakes, b-Naphthol pigments, Naphthol AS pigments, benzimidazolone pigments, disazo condensation pigments, metal complex pigments, isoindolinone and isoindoline pigments, polycyclic pigments, phthalocyanine pigments, quinacridone pigments, perylene and perinone pigments, thioindigo pigments, anthrapyrimidone pigments, flavanthrone pigments, anthanthrone pigments, dioxazine pigments, triarylcarbonium pigments, quinophthalone pigments, diketopyrrolo pyrrole pigments, titanium oxide, and iron oxide.

[0029] It is contemplated that pigments other than those listed can be used, provided that the pigment is suitable for use in an inkjet printer, including being of a suitable size depending on the nozzle to be employed. In various embodiments, the pigment is in the form of particles having a particle size of from about 50 nm to about 250 nm or from about 100 nm to about 110 nm.

[0030] In embodiments in which the colorant is a dye, the dye can be, by way of example and not limitation, a reactive dye, direct dye, anionic dye, acid dye, basic dye, phthalocyanine dye, methine or polymethine dye, merocyanine dye, azamethine dye, azine dye, quinophthalone dye, thiazine dye, oxazine dye, anthraquinone, or a metal-complex dye. Other dyes known to those in the art may be used, such as water-soluble dyes conventionally used in inkjet printing applications.

[0031] In various embodiments, the colorant is present in the printing composition in an amount of from about 0.5 wt% to about 5.0 wt% based on a total weight of the printing composition. For example, the colorant may be present in an amount of from about 0.5 wt% to about 1.0 wt%, from about 1.0 wt% to about 2.0 wt%, from about 2.5 wt% to about 5.0 wt%, or from about 1.0 wt% to about 5.0 wt% based on a total weight of the printing composition, depending on the particular embodiment. The particular amount of colorant may vary depending on the particular colorant used and the desired final color of the printing composition, as will be understood by those in the art.

[0032] The printing composition further includes at least one light-activated monomer, at least one oligomer, and at least one resin, which enhance adhesion of the colorant to the surface of the substrate and harden the image upon curing. In some embodiments, the light- activated monomer, oligomer, and resin are also selected to provide other functional properties to the image, including but not limited to alkali resistance and print layer durability.

[0033] As used herein, a light-activated monomer is a monomer that is photocurable. In some embodiments, the light-activated monomer is an ultraviolet (UV) monomer that is UV curable (cured upon exposure to UV light). In various embodiments, the light-activated monomer can be used to adjust the viscosity of the printing composition and contribute to the polymerization reaction discussed in greater detail below. The light-activated monomer, sometimes referred to as a reactive diluent, can be a mono-functional monomer, a bi functional monomer, or a multi-functional monomer, depending on the particular embodiment. Without being bound by theory, mono-functional monomers can support the curing of the linear polymer, which improves the flexibility and adhesion of the ink. Bi functional and multi-functional monomers can be used to function not only as reactive diluents, but also as cross-linking agents, which can impact the hardness, toughness, and strength of the image. The light-activated monomer is used in various embodiments to accelerate the curing process. In various embodiments, the light-activated monomer can be a (meth)acrylate, vinyl, or vinyl ether, including but not limited to, styrene, butyl acrylate, isooctyl acrylate, isobomyl acrylate, tripropylene glycol diacrylate, glycol diacrylate, and trimethylolpropane triacrylate.

[0034] The printing composition can include from about 15 wt% to about 40 wt%, from about 18 wt% to about 37 wt%, or from about 20 wt% to about 35 wt% light-activated monomer based on a total weight of the printing composition.

[0035] The oligomer included in the printing composition is a reactive, low molecular weight polymer that provides print layers with properties such as chemical resistance, hardness, and flexibility. In various embodiments, the oligomer is a double bond-containing unsaturated polymer. The oligomer can be, by way of example and not limitation, a polyacrylate, epoxy acrylate, urethane acrylate, unsaturated polyester, or polyolefm/thiol.

[0036] The printing composition can include from about 2.5 wt% to about 20 wt%, from about 4 wt% to about 18 wt%, or from about 5 wt% to about 15 wt% oligomer based on a total weight of the printing composition.

[0037] In various embodiments, the resin included in the printing composition is an organic or inorganic resin selected from the group consisting of epoxy resins, amino resins, and silicone resins. In embodiments, the printing composition includes two or more of the resins. For example, the printing composition can include an amino resin and an epoxy resin, an amino resin and a silicone resin, or an epoxy resin and a silicone resin. Other combinations of resins, including combinations including two different types of epoxy resins, amino resins, and/or silicone resins, are also contemplated. The resins for use herein are commercially available. In some embodiments, the silicone resin may be defined as a silsesquioxane uncured silicone resin component, and more preferably (but not limited to) a divinyl- hexamethyl-octasila-silsesquioxane uncured silicone resin component (VimMeeSis) whose chemical structure is illustrated in FIG. 5 along with a thermal desorption gas chromatography mass spectrum of the divinyl-hexamethyl-octasila-silsesquioxane uncured silicone resin component.

[0038] As is understood by a person skilled in the art, the VimMeeSis silsesquioxane uncured silicone resin component whose chemical structure is illustrated in FIG. 5 is a condensation product of two molecules of a vinyl-tri-substitutable silane and six molecules of a methyl-tri-substitutable silane. The tri-substitutable portions of the foregoing vinyl silane and methyl silane molecules may comprise, for example and without limitation, substitutable chemical functionality including but not limited to suitable halide functionality and suitable alkoxide functionality. Thus, suitable silane starting materials that may be used for preparing the silsesquioxane uncured silicone resin component whose chemical structure is illustrated in FIG. 5 may include, but are not limited to, vinyl-triethoxy-silane and methyl-trimethoxy- silane. The silsesquioxane uncured silicone resin component whose chemical structure is illustrated in FIG. 5 is further characterized as a transparent viscous fluid having about 30% to about 45% solids, a viscosity from about 10 to about 20 centipoise at 25 °C, a density from about 0.9 to about 1.0 gram/cm³ at 23 °C, and a surface tension from about 26 to about 29 dynes/cm.

[0039] A suitable uncured silicone resin component (i.e., including but not limited to the VimMeeSis silsesquioxane whose chemical structure is illustrated in FIG. 5) for use herein in accordance with some embodiments is available from any of several commercial sources as an appropriately designated uncured silicone resin. As noted above, the uncured silicone resin component may alternatively be prepared in-situ from reaction of a 1 :3 ratio of an appropriate vinyl silane and an appropriate methyl silane.

[0040] The printing composition can include from about 0.05 wt% to about 25 wt%, from about 1.0 wt% to about 22 wt%, or from about 5 wt% to about 20 wt% total resin based on a total weight of the printing composition. As used herein,“total resin” refers to a total amount of resin selected from the group consisting of epoxy resins, amino resins, and silicone resins.

[0041] In various embodiments, the printing composition further includes at least one photoinitiator. The photoinitiator influences the UV cure rate of the printing composition and undergoes a reaction upon absorbing light to produce a reactive species. These compounds then catalyze and/or initiate further reactions such as, for example, polymerization and/or curing reactions. According to various embodiments, the photoinitiator can be a free radical initiator or a cationic initiator. Suitable free radical initiators include, by way of example and not limitation, carbonyl compounds, azo compounds, organic sulfur compounds, redox substances, halogen compounds, organometallic compounds, and salty dyes. Commercially available photoinitiators suitable for use include 1 -hydroxy cyclohexylphenyl ketone (e.g., IRGACURE™ 184 available from BASF)); bis(2,6-dimethoxybenzoyl)-2,4,4- trimethylpentylphosphine oxide (e.g., commercial blends IRGACURE™ 1800, 1850, and 1700 available from BASF); 2,2-dimethoxy-2-phenylacetophenone (e.g., IRGACURE™ 651, available from BASF); bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (IRGACURE™ 819); (2,4,6-trimethylbenzoyl)diphenyl phosphine oxide (LUCIRIN™ TPO, available from BASF); ethoxy(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (LUCIRIN™ TPO-L from BASF); and combinations thereof. Cationic initiators include a positive charge that is activated by radiation to promote curing. Curing is based on a ring opening in the epoxide through action of the Lewis acid that is produced by photolysis of the cationic photoinitiator. Suitable cationic initiators include, by way of example and not limitation, triaryl sulfonium salts.

[0042] The printing composition can include from about 0.1 wt% to about 15.0 wt%, from about 0.5 wt% to about 10 wt%, or from about 1.0 wt% to about 5.0 wt% photoinitiator based on a total weight of the printing composition.

[0043] In various embodiments, the printing composition further includes one or more solvents and/or one or more dispersants. Solvents are the primary carriers that carry the colorant (e.g., pigment powder) to be delivered by the print head. Solvents also control the drying time, wettability, and viscosity of the printing composition in such a manner that these properties do not become sensitive to temperature in order to maintain smooth operation. In various embodiments, the solvents are organic solvents, such as alcohols esters, and polyether polyols. Suitable solvents include, by way of example and not limitation, ethanol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, ethylene glycol, glycerol, 3 -methoxy-3 -methyl- 1- butanol, 1, 2-propanediol, 1,3 -propanediol, 2-ethyl-2-(hydroxymethyl)-l 3 -propanediol, 2- butyl-2-ethyl- 1,3 -propanediol, 2,2-dimethylpropane-l,3-diol, 1, 2-butylene glycol, 1,3- butylene glycol, 2,3-butylene glycol, 2, 2-dimethyl-l, 3 -propanediol, l,5-pentanediol, 2- methyl-l,4-pentadiene, 2,4-diethyl-2,4-pentanediol, 2-butene-l 4-diol, 2,5-hexanediol, 2,5- dimethylhexane-2,5-diol, 2-ethyl- 1, 3 -hexanediol, ethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, diethylene glycol dibutyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, propylene glycol dimethyl ether, triethylene glycol dimethyl ether, ethylene glycol tertiary butyl ether, ethylene glycol monobutyl ether, propylene glycol tertiary butyl ether, diethylene glycol tertiary butyl ether, propylene glycol monomethyl ether, propylene glycol methyl propylene ether, propylene glycol methyl butyl ether, dipropylene glycol methyl butyl ether, dipropylene glycol methyl propylene ether, ethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol methyl ether acetate, dipropylene glycol methyl ether acetate, and/or ethylene glycol monobutyl ether acetate, and combinations thereof. In some embodiments, the solvent is non-aqueous (does not contain water), and thus in some embodiments, the printing composition is non-aqueous.

[0044] The printing composition can include from about 20 wt% to about 80 wt%, from about 40 wt% to about 75 wt%, or from about 50 wt% to about 70 wt% solvent based on a total weight of the printing composition.

[0045] In embodiments including one or more dispersants, the dispersant enables the colorant (e.g., the pigment powder) to be evenly distributed in the solvent and ensure that the colorant particles do not agglomerate or form into large particles before printing. In various embodiments, the dispersants are water-soluble or oil-soluble polymers, depending on the particular embodiment. Suitable dispersants include, by way of example and not limitation, benzoic acid and its derivatives, such as polyacrylic acid polymer, copolymers, and the like. In some embodiments, a dispersant material may include an acrylic polymer material. As just one example, an acrylic polymer material dispersant suitable for compatibility with an uncured resin component and a solvent composition in accordance with an embodiment is commercially available. According to other embodiments, the dispersant may be or may include one or more of the following, including but not limited to a polyurethane and/or polymethyl-methacrylate copolymer dispersant, an acrylate copolymer with pigment affinity groups, a high molecular weight block copolymer with pigment affinic groups, a polycarboxylic acid salt of polyamine amides, alkylol ammonium salt of a copolymer with acidic groups, a phosphoric ester salt of a high molecular weight copolymer with pigment- affinity groups, and/or a hydroxy-functional carboxylic acid ester with pigment affinity groups, among others. In some embodiments, dispersants for use within the uncured inkjet ink composition are commercially available.

[0046] The printing composition can include from about 0.5 wt% to about 5.0 wt%, from about 0.5 wt% to about 2.0 wt%, from about 0.5 wt% to about 1.0 wt%, from about 2.0 wt% to about 4.0 wt%, or from about 1.0 wt% to about 2.0 wt% dispersant based on a total weight of the printing composition. [0047] According to some embodiments, the printing composition can also include a flow promotor that improves the wetting of an uncured inkjet ink composition onto a substrate (for example, a glass, glass-ceramic, ceramic, metal oxide, metal, and/or polymeric substrate), thus preventing de-wetting of the uncured composition from a substrate prior to curing. In some embodiments, the uncured inkjet ink composition includes a flow promotor in a range from 0.5 to 3.5 weight%, 0.5 to 3 weight%, 0.5 to 2.5 weight%, 0.5 to 2 weight%, 0.5 to 1.5 weight%, 0.5 to 1 weight%, 1 to 3.5 weight%, 1 to 3 weight%, 1 to 2.5 weight%, 1 to 2 weight%, 1 to 1.5 weight%, 1.5 to 3.5 weight%, 1.5 to 3 weight%, 1.5 to 2.5 weight%, 1.5 to 2 weight%, 2 to 3.5 weight%, 2 to 3 weight%, 2 to 2.5 weight%, 2.5 to 3.5 weight%, 2.5 to 3 weight%, 3 to 3.5 weight%, or any ranges and sub-ranges therebetween. In some embodiments, the flow promotor may be a modified polyether polydimethylsiloxane. In some embodiments, flow promotors for use within the composition are commercially available.

[0048] The printing composition can also include one or more additives, depending on the particular embodiment. In some embodiments, the additive is a surface control agent including but not limited to a polydimethylsiloxane solution, a polyether polyester modified organic siloxane solution, an alkyl modified organic siloxane solution, an acrylate copolymer, a polyacrylate solution, an OH, and/or a polyacrylate copolymer with OH functional groups solution, among others. In embodiments, the additive can include a degassing agent. The degassing agent may be, for example, a polydimethylsiloxane and/or a modified polydimethylsiloxane. Other additives known and used by those having skill in the art are contemplated. Other additives may include, by way of example and not limitation, antioxidants, ultraviolet absorbers, photostabilizers, silane coupling agents, leveling agents, surfactants, preservatives, plasticizers, lubricants, fillers, aging inhibitors, wetting agents, coating surface improvers, and the like.

[0049] When included in the printing composition, the printing composition can include from about 0.1 wt% to about 5.0 wt%, from about 0.25 wt% to about 3.0 wt%, or from about 0.5 wt% to about 2.0 wt% additive based on a total weight of the printing composition.

[0050] According to various embodiments, the dispersant is mixed, ground into, or otherwise combined with one or more colorants to make a colorant paste. The colorant paste, with the dispersant material pre-mixed, can be commercially available in some embodiments. The colorant paste can be mixed with the light-activated monomer, oligomer, resin, and the solvent mixture, or mixed with a pre-combined mixture thereof, to form the uncured printing composition.

[0051] In various embodiments, the printing composition can be used to print on a substrate 101 having at least a portion that is non-planar. In such embodiments, the printing composition is jetted onto the substrate to form a printed substrate 100. More particularly, in various embodiments, the printing composition is jetted onto at least the portion of the substrate that is non-planar, as shown in FIGS. 1-4. The printing composition can be jetted onto the substrate in a direction that is substantially normal to the planar portion of the substrate. The printing composition can be jetted using any suitable print head, as will be known to those in the art, such as one or more print heads of a digital printer.

[0052] After the printing composition is jetted onto the printed substrate 100, the printed substrate is exposed to a light source to at least partially cure the printing composition through photocuring. In some embodiments, the light source may be a UV light source. As used herein, the term“UV light source” refers to a source of ultraviolet light, which is electromagnetic radiation with a wavelength of about 10 nm to about 400 nm. In the context of UV curing, wavelengths can be selected from, for example, the UVA and UVB wavebands located between 280 nm and 400 nm, or more particularly, from about 360 nm to about 395 nm. The UV light source can be, by way of example and not limitation, a UV lamp. In one particular embodiment, the UV light source is a blue LED light source emitting light at wavelengths of about 360 nm and about 395 nm.

[0053] The light source can be incorporated into an inkjet printing apparatus, or can be a standalone device positioned proximate to the inkjet printing apparatus. In some embodiments, the light source is mounted to the inkjet printing apparatus. In various embodiments, the light source at least partially cures the printing composition in about 5 seconds, in about 10 seconds, in about 30 seconds, in about 45 seconds, in about 1 minute, or the like. Without being bound by theory, the light source may be used to produce a photocuring effect, preventing the flow of ink from dripping on the non-planar portions 104 of the printed substrate 100 that would normally result in uneven print layer thickness and distorted image resolution. [0054] In various embodiments, after the printed substrate 100 is exposed to the light source, the printed substrate 100 is heated in an oven to thermally cure the printing composition. In particular, the printed substrate 100 can be heated in an oven at a temperature of from about 150 °C to about 180 °C for about 10 minutes to about 30 minutes. The oven can be incorporated into the inkjet printing apparatus, or can be a standalone device positioned proximate to the inkjet printing apparatus. Without being bound by theory, heating the printed substrate 100 in the oven can fully cure the printing composition to produce a cured image on the substrate, enhance the performance of the printed layer, and increase the adhesion strength of the cured image. In the processes described above, photocuring induces a partial cure of the printing composition so that the composition begins to harden and crosslink to minimize flowing of the printing composition. In some embodiments, this is beneficial when printing on a non-planar surface as the partial cure reduces the flowability of the composition and helps to maintain a uniform thickness of the printing composition. In some embodiments, the thermal cure completes the hardening and crosslinking of the composition. In some embodiments, the thermal cure also drives off volatile components, such as the solvents (if still present) to ensure adequate adhesion of the printing composition to the substrate.

[0055] In various embodiments, after photocuring and thermal curing, the cured image formed on the substrate includes at least the colorant and a polymer formed from the at least one light-activated monomer, the at least one oligomer, and the at least one resin selected from the group consisting of epoxy resins, amino resins, and silicone resins. In some embodiments, the polymer can also be formed from the photoinitiator. The solvents, dispersants, and other additives, depending on the particular components employed, can be removed from the image during curing. For example, the solvent may evaporate during the thermal curing of the printed image.

[0056] The cured image may have a thickness of from about 0.5 pm to about 50 pm, depending on the particular embodiment. In particular, the thickness of the cured image may vary depending on the thickness of the image jetted onto the substrate 101, the run speed of the printing apparatus, the viscosity of the printing composition, and the like. In various embodiments, the thickness of the cured image is substantially constant along a width of the printed substrate 100. As used herein,“substantially constant” means that the thickness of the cured image varies less than 10% along the width of the printed substrate 100. In some embodiments, the photocure followed by the thermal cure permits a substrate with a bend height h (shown in FIG. 2) of up to 10 mm and/or a bend or curve with a radius of curvature ri (shown in FIG. 2) of up to 5mm to have a substantially constant thickness along a width of a surface including planar and bent/curved portions of the surface.

[0057] Additionally, in various embodiments, the cured image has an adhesion to the substrate that is greater than or equal to 4B on a cross hatch adhesion test when measured in accordance with ASTM D3359-09e2 (and its progeny). In some embodiments, the cured inkjet ink composition coating meets standard reliability and environmental tests for inks including thermal cycle testing for 12 hours, high temperature/high humidity testing for 87 hours, chemical resistance testing for 72 hours, salty water testing for 72 hours, snap tape test, and UV exposure testing for 72 hours.

[0058] Accordingly, various embodiments described herein may be employed to form printed images on three-dimensional substrates, including substrates having two or more non- planar edges. Various embodiments enable the printed image to be printed on non-planar portions of the substrate and cured using UV and thermal curing methods, which can reduce image defects while providing adhesion to the substrate that is at least as good as conventional screen printing methods.

[0059] According to a first aspect, the disclosure provides a printing composition including a colorant; at least one light-activated monomer; at least one oligomer; at least one resin selected from the group consisting of epoxy resins, amino resins, and silicone resins; and a photoinitiator.

[0060] According to a second aspect, the disclosure provides a printing composition of the first aspect, wherein the light-activated monomer is selected from the group consisting of (meth)acrylates, vinyls, and vinyl ethers.

[0061] According to a third aspect, the disclosure provides a printing composition of the first or second aspects, wherein the oligomer is selected from the group consisting of polyacrylates, epoxy acrylates, urethane acrylates, unsaturated polyesters, and polyolefm/thiols. [0062] According to a fourth aspect, the disclosure provides a printing composition of any of the first through third aspects, wherein the printing composition includes from about 0.5 wt% to about 5 wt% colorant; from about 1.0 wt% to about 5 wt% photoinitiator; and from about 25 wt% to about 70 wt% of a mixture of the at least one light-activated monomer, the at least one oligomer, and the at least one resin.

[0063] According to a fifth aspect, the disclosure provides a printing composition of any of the first through fourth aspects, further comprising one or more organic solvents.

[0064] According to a sixth aspect, the disclosure provides a printing composition of any of the first through fifth aspects, further comprising at least one dispersing agent.

[0065] According to a seventh aspect, the disclosure provides a printing composition of the sixth aspect, wherein the at least one dispersing agent is present in an amount of from about 0.5 wt% to about 5 wt%.

[0066] According to an eighth aspect, the disclosure provides a printing composition of any of the first through seventh aspects, wherein the printing composition is both photocurable and thermally curable.

[0067] In a ninth aspect, the disclosure provides a method of printing on a substrate having at least a portion that is non-planar, the method comprising: jetting, onto the substrate, a printing composition comprising a colorant, at least one light-activated monomer, at least one oligomer, at least one resin, and a photoinitiator, wherein the at least one resin is selected from the group consisting of epoxy resins, amino resins, and silicone resins to form a printed substrate; exposing the printed substrate to a light source to at least partially cure the printing composition; and heating the printed substrate to cure the printing composition after exposing the printed substrate to the light source.

[0068] In a tenth aspect, the disclosure provides the method of the ninth aspect, wherein the light source emits light at a wavelength of from about 360 nm to about 395 nm.

[0069] In an eleventh aspect, the disclosure provides the method of the eighth or ninth aspects, wherein the jetting comprises jetting the printing composition onto the portion of the substrate that is non-planar. [0070] In a twelfth aspect, the disclosure provides the method of the eleventh aspect, wherein a thickness of the printing composition after the heating varies less than 10% along the width of the substrate.

[0071] In a thirteenth aspect, the disclosure provides the method of the twelfth aspect, wherein the non-planar portion comprises a bend height h of up to 10 mm.

[0072] In a fourteenth aspect, the disclosure provides the method of the twelfth or thirteenth aspect, wherein the non-planar portion has a curve with a radius of curvature ri of up to 5mm.

[0073] In a fifteenth aspect, the disclosure provides the method of any of the ninth through fourteenth aspects, wherein the heating comprises heating the printed substrate at a temperature of from about 150 °C to about 180 °C.

[0074] In a sixteenth aspect, the disclosure provides the method of any of the ninth through fifteenth aspects, wherein the heating comprises heating the printed substrate for about 10 to about 30 minutes.

[0075] In a seventeenth aspect, the disclosure provides the method of any of the ninth through sixteenth aspects, wherein the jetting comprises jetting the printing composition onto the substrate using one or more print heads of a digital printer.

[0076] In an eighteenth aspect, the disclosure provides the method of any of the ninth through seventeenth aspects, wherein the printing composition comprises: from about 0.5 wt% to about 5 wt% of the colorant; from about 1.0 wt% to about 5 wt% of the photoinitiator; and from about 25 wt% to about 70 wt% of a mixture of the at least one light- activated monomer, the at least one oligomer, and the at least one resin.

[0077] In a nineteenth aspect, the disclosure provides the method of any of the ninth through eighteenth aspects, wherein the substrate is selected from the group consisting of glass, glass-ceramic, ceramic, metal oxide, metal and polymeric substrates.

[0078] In a twentieth aspect, the disclosure provides a printed substrate comprising: a substrate having at least a portion that is non-planar; and a cured image formed on the substrate comprising: a colorant; and a polymer formed from at least one light-activated monomer, at least one oligomer, and at least one resin selected from the group consisting of epoxy resins, amino resins, and silicone resins.

[0079] In a twenty-first aspect, the disclosure provides the printed substrate of the twentieth aspect, wherein the cured image is formed at least partially on the portion of the substrate that is non-planar.

[0080] In a twenty-second aspect, the disclosure provides the printed substrate of the twenty- first aspect, wherein a thickness of the cured image varies less than 10% along the width of the printed substrate.

[0081] In a twenty-third aspect, the disclosure provides the printed substrate of the twenty- second aspect, wherein the non-planar portion comprises a bend height h of up to 10 mm.

[0082] In a twenty-fourth aspect, the disclosure provides the printed substrate of the twenty-second or twenty-third aspect, wherein the non-planar portion has a curve with a radius of curvature ri of up to 5mm.

[0083] In a twenty-fifth aspect, the disclosure provides the printed substrate of any of the twentieth through twenty-fourth aspects, wherein the at least one light-activated monomer is selected from the group consisting of (meth)acrylates, vinyls, and vinyl ethers.

[0084] In a twenty-sixth aspect, the disclosure provides the printed substrate of any of the twentieth through twenty-fifth aspects, wherein the oligomer is selected from the group consisting of polyacrylates, epoxy acrylates, urethane acrylates, unsaturated polyesters, and polyolefm/thiols.

[0085] In a twenty-seventh aspect, the disclosure provides the printed substrate of any of the twentieth through twenty-sixth aspects, wherein the cured image has a thickness of from about 0.5 pm to about 50 pm on a surface of the substrate.

[0086] In a twenty-eighth aspect, the disclosure provides the printed substrate of any of the twentieth through twenty- seventh aspects, wherein an adhesion of the cured image to the substrate is greater than or equal to 4B on a cross hatch adhesion test. [0087] In a twenty-ninth aspect, the disclosure provides the printed substrate of any of the twentieth through twenty-eighth aspects, wherein the portion of the substrate that is non- planar comprises at least two edges of the substrate.

[0088] In a thirtieth aspect, the disclosure provides the printed substrate of any of the twentieth through twenty-ninth aspects, wherein the substrate is selected from the group consisting of glass, glass-ceramic, ceramic, metal oxide, metal and polymeric substrates.

[0089] It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments described herein without departing from the spirit and scope of the claimed subject matter. Thus it is intended that the specification cover the modifications and variations of the various embodiments described herein provided such modification and variations come within the scope of the appended claims and their equivalents.

Claims

What is claimed is:

1. A printing composition comprising:

a colorant;

at least one light-activated monomer;

at least one oligomer;

at least one resin selected from the group consisting of epoxy resins, amino resins, and silicone resins; and

a photoinitiator.

2. The printing composition according to claim 1, wherein the light-activated monomer is selected from the group consisting of (meth)acrylates, vinyls, and vinyl ethers.

3. The printing composition according to claim 1 or 2, wherein the oligomer is selected from the group consisting of polyacrylates, epoxy acrylates, urethane acrylates, unsaturated polyesters, and polyolefm/thiols.

4. The printing composition according to any preceding claim, wherein the printing composition comprises:

from about 0.5 wt% to about 5 wt% colorant;

from about 1.0 wt% to about 5 wt% photoinitiator; and

from about 25 wt% to about 70 wt% of a mixture of the at least one light-activated monomer, the at least one oligomer, and the at least one resin.

5. The printing composition according to any preceding claim, further comprising one or more organic solvents.

6. The printing composition according to any preceding claim, further comprising at least one dispersing agent.

7. The printing composition according to claim 6, wherein the at least one dispersing agent is present in an amount of from about 0.5 wt% to about 5 wt%.

8. The printing composition according to any preceding claim, wherein the printing composition is both photocurable and thermally curable.

9. A method of printing on a substrate having at least a portion that is non-planar, the method comprising:

jetting, onto the substrate, a printing composition comprising a colorant, at least one light-activated monomer, at least one oligomer, at least one resin, and a photoinitiator, wherein the at least one resin is selected from the group consisting of epoxy resins, amino resins, and silicone resins to form a printed substrate;

exposing the printed substrate to a light source to at least partially cure the printing composition; and

heating the printed substrate to cure the printing composition after exposing the printed substrate to the light source.

10. The method of claim 9, wherein the light source emits light at a wavelength of from about 360 nm to about 395 nm.

11. The method of claim 9 or 10, wherein the jetting comprises jetting the printing composition onto the portion of the substrate that is non-planar.

12. The method of claim 11, wherein a thickness of the printing composition after the heating varies less than 10% along the width of the substrate.

13. The method of claim 12, wherein the non-planar portion comprises a bend height h of up to 10 mm.

14. The method of claim 12 or 13, wherein the portion of the non-planar portion has a curve with a radius of curvature r_/ of up to 5mm.

15. The method of any one of claims 9-14, wherein the heating comprises heating the printed substrate at a temperature of from about 150 °C to about 180 °C.

16. The method of any one of claims 9-15, wherein the heating comprises heating the printed substrate for about 10 to about 30 minutes.

17. The method of any one of claims 9-16, wherein the jetting comprises jetting the printing composition onto the substrate using one or more print heads of a digital printer.

18. The method of any one of claims 9-17, wherein the printing composition comprises: from about 0.5 wt% to about 5 wt% of the colorant;

from about 1.0 wt% to about 5 wt% of the photoinitiator; and

19. The method of any one of claims 9-18, wherein the substrate is selected from the group consisting of glass, glass-ceramic, ceramic, metal oxide, metal and polymeric substrates.

20. A printed substrate comprising:

a substrate having at least a portion that is non-planar; and

a cured image formed on the substrate comprising:

a colorant; and

a polymer formed from at least one light-activated monomer, at least one oligomer, and at least one resin selected from the group consisting of epoxy resins, amino resins, and silicone resins.

21. The printed substrate of claim 20, wherein the cured image is formed at least partially on the portion of the substrate that is non-planar.

22. The printed substrate of claim 21, wherein a thickness of the cured image varies less than 10% along the width of the printed substrate.

23. The printed substrate of claim 22, wherein the non-planar portion comprises a bend height h of up to 10 mm.

24. The printed substrate of claim 22 or 23, wherein the portion of the non-planar portion has a curve with a radius of curvature ri of up to 5mm.

25. The printed substrate of any one of claims 20-24, wherein the at least one light- activated monomer is selected from the group consisting of (meth)acrylates, vinyls, and vinyl ethers.

26. The printed substrate of any one of claims 20-25, wherein the oligomer is selected from the group consisting of polyacrylates, epoxy acrylates, urethane acrylates, unsaturated polyesters, and polyolefm/thiols.

27. The printed substrate of any one of claims 20-26, wherein the cured image has a thickness of from about 0.5 pm to about 50 pm on a surface of the substrate.

28. The printed substrate of any one of claims 20-27, wherein an adhesion of the cured image to the substrate is greater than or equal to 4B on a cross hatch adhesion test.

29. The printed substrate of any one of claims 20-28, wherein the portion of the substrate that is non-planar comprises at least two edges of the substrate.

30. The printed substrate of any one of claims 20-29, wherein the substrate is selected from the group consisting of glass, glass-ceramic, ceramic, metal oxide, metal and polymeric substrates.