Stable liquid crosslinking agent composition for heat curable ink

Abstract

The present disclosure provides an ink vehicle composition comprising a crosslinker compound of formula (I), a hydroxy-functional polymer, and a volatile diluent, and substantially free of butanol. Also provided is a thermosetting heat-curable ink comprising the ink vehicle composition, and a method of applying the thermosetting heat-curable ink to print on a surface of a substrate. The ink vehicle composition and the thermosetting heat-curable ink herein may be stable at room temperature for about 6 to about 24 months. [Formula 1] TIFF2025506799000012.tif40149

Description

[Technical field]

[0001] The present disclosure relates to stable compositions containing 1,3,5-triazine carbamate (TACT) crosslinkers and methods for their preparation, for example for use in high speed offset printing of thermosetting inks. [Background technology]

[0002] TACT compounds are trifunctional melamine-based crosslinkers with reactive carbamate functional groups. TACT crosslinkers are solid materials that require dissolution in a solvent. TACT crosslinkers are not soluble in polyether glycol-based solvents, and commercially available TACT crosslinkers are typically supplied as 50-52% solutions in n-butanol. However, due to the boiling point of butanol, butanol solutions of TACT cannot obtain suitable printing properties for use in high-speed offset printing of thermosetting (heat-curable) ink formulations. Also, evaporation of butanol during storage can cause the solid crosslinker to precipitate from the ink, disrupting the printing process. Summary of the Invention [Problem to be solved by the invention]

[0003] To date, the use of TACT crosslinkers in heat-curable high-speed offset printing inks (such as those useful for printing images on metal surfaces) remains a technical challenge. TACT is not soluble in common ink diluents by itself due to its solubility parameters. Thus, there remains a need for stable TACT crosslinker compositions for use in heat-curable high-speed offset printing inks, desirably with comparable or better printing performance compared to existing formulations that do not use TACT as a curing agent. [Means for solving the problem]

[0004] In one embodiment, R 1 , R 2 , and R 3 are independent C 1-10a crosslinker compound of formula (I) which is alkyl; [ka] a hydroxy-functional polymer; a non-volatile diluent; A substantially butanol-free ink vehicle composition is disclosed.

[0005] In another aspect, there is provided a method of preparing an ink vehicle composition, comprising the steps of: R 1 , R 2 , and R 3 are independent C 1-10 dissolving and mixing a crosslinker compound of formula (I), which is an alkyl, in butanol, a hydroxy-functional polymer, and a non-volatile diluent to form a mixture; [ka] and evaporating at least 98% of the butanol from the mixture to provide the composition of claim 1.

[0006] In another aspect, a heat curable ink is disclosed that includes (a) the disclosed ink vehicle composition and (b) a colorant.

[0007] In another aspect, a method of printing ink onto a substrate is disclosed that includes applying a disclosed thermosetting ink to a surface of the substrate and heating the applied thermosetting ink to cure the applied thermosetting ink. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The present disclosure provides a liquid crosslinker composition comprising a TACT crosslinker compound. The liquid crosslinker composition is particularly suitable for use in preparing curable compositions such as high solids coating compositions, overprint varnishes, printable inks, and other related applications. Also, the TACT crosslinker process does not release or generate formaldehyde. For heat-curable inks, the TACT crosslinker is mixed with a hydroxy-functional polymer and a non-volatile diluent to form a heat-curable composition, which can be used as an ink vehicle composition for preparing printable inks. The crosslinker compositions and inks described herein may remain stable at room temperature for extended periods of time without crosslinking, solid precipitation, or stratification of components. Thus, the present disclosure provides a formaldehyde-free, heat-curable, printable ink that may be useful for printing images on hard surfaces, such as the metal surfaces of containers.

[0009] (1.Definition) As used herein, the terms "comprise(s)", "include(s)", "having", "has", "can", "contain(s)", and variations thereof are intended to be open-ended conjunction phrases, terms, or words that do not exclude the possibility of additional acts or structures. The singular forms "a", "an", and "the" include plural references unless the context clearly dictates otherwise. The present disclosure also contemplates other embodiments that "comprising", "consisting of", and "consisting essentially of" the embodiments or elements presented herein, whether or not expressly stated.

[0010] The modifier "about" used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (e.g., includes at least the degree of error associated with measurement of the particular quantity). The modifier "about" should also be considered to disclose a range defined by the absolute values ​​of the two endpoints. For example, the phrase "about 2 to about 4" also discloses the range "about 2 to about 4". The term "about" may refer to plus or minus 10% of the indicated numerical value. For example, "about 10%" may indicate a range of 9% to 11%, and "about 1" may mean 0.9 to 1.1. Other meanings of "about" may be apparent from the context, such as rounding, so for example, "about 1" may mean 0.5 to 1.4.

[0011] For the recitation of numerical ranges herein, each intervening numerical value with the same degree of precision is expressly contemplated, for example, for the range 6 to 9, the numerical values ​​7 and 8 are contemplated in addition to 6 and 9, and for the range 6.0 to 7.0, the numerical values ​​6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, and 7.0 are expressly contemplated.

[0012] The term "alkyl" as used herein means a straight or branched saturated hydrocarbon chain containing 1 to 20 carbon atoms. 1-6 The term "alkyl" means a straight or branched chain hydrocarbon containing from 1 to 6 carbon atoms. Representative examples of alkyl include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, 3-methylhexyl, 2,2-dimethylpentyl, 2,3-dimethylpentyl, n-heptyl, n-octyl, n-nonyl, n-decyl, and the like.

[0013] In certain embodiments, the number of carbon atoms in an alkyl group is indicated by the prefix "C x-y " or "C x -C y-", where x is the minimum number of carbon atoms in the substituent and y is the maximum number. Thus, for example, "C 1-4 "Alkyl" or "C1-C4-alkyl" refers to an alkyl substituent containing from 1 to 4 carbon atoms.

[0014] The term "butanol" refers to n-butanol, which has the formula CH3(CH2)3OH.

[0015] The term "cure" or "curing" refers to a process that results in hardening and / or crosslinking of hydroxy-functional polymers with other hydroxy-functional polymers, within the same polymer, or combinations thereof. Additionally, non-volatile diluents may also interact with crosslinkers depending on whether the non-volatile diluent has functional groups that can react with the crosslinker compound. Curing may be initiated by heating.

[0016] The term "substantially free" means that the component is not present in the composition or is present in the composition in an amount of 2% or less by weight of the composition, including 1% or less by weight, 0.5% or less by weight, 0.01% or less by weight, 0.005% or less by weight, or 0.001% or less by weight.

[0017] The terms "hydroxy" and "hydroxyl" are used interchangeably herein to refer to an --OH group.

[0018] The term "molecular weight" refers to number average molecular weight, unless otherwise specified. Molecular weight can be measured by standard methods known in the art, such as gel permeation chromatography, size exclusion chromatography, rheological analysis, etc.

[0019] The terms "non-volatile" and "volatile" with respect to components of the ink vehicle composition and / or ink refer to the percentage of the components (e.g., non-volatile diluents) that are released from the ink vehicle composition and / or ink under given bake conditions, such as those described in ASTM D2369-20. For example, "volatile" refers to components that substantially evaporate from the ink vehicle composition and / or ink when heated at 110±5° C. for 60 minutes (e.g., 90% or more, 95% or more, 99% or more, or about 100%). "Non-volatile" refers to components that do not substantially evaporate from the ink vehicle composition and / or ink when heated at 110±5° C. for 60 minutes (e.g., less than 10%, less than 5%, less than 1%, or about 0%).

[0020] The term "oligomer" refers to a material having a molecular weight of about 1,000 g / mol to 3,000 g / mol.

[0021] The term "polymer" refers to a macromolecule having a molecular structure consisting of many smaller units bonded together. The smaller units are generally derived from monomers or oligomers. The term is used interchangeably herein with resin.

[0022] The term "room temperature" means a temperature of about 20°C to about 25°C.

[0023] 2. Ink Vehicle Composition In one aspect, the present disclosure provides 1 , R 2 , and R 3 are independent C 1-10 a crosslinker compound of formula (I) which is alkyl; [ka] a hydroxy-functional polymer; a non-volatile diluent; A substantially butanol-free ink vehicle composition is disclosed.

[0024] In some embodiments, R 1 , R 2 , and R3 are independent C 1-4 In some embodiments, R 1 , R 2 , and R 3 are independently n-butyl (-CH2CH2CH2CH3) or methyl (-CH3). TACT-based crosslinker compounds are commercially available and are typically supplied in n-butanol as the solvent. n-butanol and other volatile co-solvents can be replaced with non-volatile diluents by suitable solvent exchange.

[0025] The crosslinker compound may also be referred to herein as 1,3,5-triazine carbamate (TACT) crosslinker. The TACT crosslinker may be used to crosslink polymers containing hydroxy, epoxy, thiol, amino, and / or carboxy functional groups. For example, the TACT crosslinker may react with hydroxy groups of hydroxy-functional polymers at 125° C. or higher to form urethane bonds. The TACT-based crosslinking process does not generate or release formaldehyde. Thus, the disclosed ink vehicle composition may be formaldehyde-free. In some embodiments, the ink vehicle composition is free or substantially free of formaldehyde.

[0026] The crosslinker compound may be employed as the sole crosslinker in the ink vehicle composition, or may be used in combination with other crosslinkers, such as amino resins or isocyanates. Other crosslinkers may be used to obtain a balance of properties. In some embodiments, the ink vehicle composition does not include any other crosslinker other than the crosslinker compound.

[0027] The ink vehicle composition may comprise from about 10% to about 90% by weight of the crosslinker compound, for example from about 20% to about 80% by weight or from about 25% to about 70% by weight.

[0028] Hydroxy-functional polymers as described herein are polymers that contain multiple hydroxy groups. For example, hydroxy-functional polymers may contain at least two, preferably more than two, hydroxy groups. The hydroxy groups may be pendant from the polymer backbone, at the ends of the polymer, or both. The hydroxy-functional polymers may be modified with one or more fatty acids. Suitable hydroxy-functional polymers include, for example, polyacrylics, polyesters, polyurethanes, and alkyd materials. Suitable hydroxy-functional polyacrylic polymers can be obtained, for example, by copolymerization of an acrylic or methacrylic ester with a hydroxy-functional acrylic or methacrylic ester, such as hydroxyethyl acrylate or methacrylate. Suitable hydroxy-functional polyesters can be obtained, for example, by reaction of a polycarboxylic acid with an excess of a polyhydric alcohol. In some embodiments, the hydroxy-functional polymer is a hydroxy-functional polyester, a hydroxy-functional polyacrylic, a hydroxy-functional polyurethane, or a combination thereof. In some embodiments, the hydroxy-functional polymer is a hydroxy-functional polyester or a hydroxy-functional polyacrylic.

[0029] The hydroxy-functional polymer may have a molecular weight and hydroxyl number suitable for use in ink formulations, such as thermosetting heat curable inks. For example, the hydroxy-functional polymer may have a weight average molecular weight (Mw) of about 1000 g / mole to about 6000 g / mole, and a number average molecular weight (Mn) of about 500 g / mole to about 3000 g / mole. Additionally, the hydroxy-functional polymer may have a hydroxyl number of about 30 to about 300 mg KOH / g polymer. The hydroxy-functional polymer may also have an acid number of about 10 to about 100 mg KOH / g polymer.

[0030] Examples of hydroxy-functional polymers include JONCRYL® 540 acrylic resin polymer (SC Johnson & Sons, Racine, WI), JONCRYL® 500 acrylic resin (SC Johnson & Sons, Racine, WI), ACRYLOID® AT-400 acrylic resin (Rohm & Haas, Philadelphia, PA), CYPLEX® 1531 polyester resin (Cytec Industries, West Paterson, NJ), CARGILL 3000 and 5776 polyester resins (Cargill, Minneapolis, MN), TONE® polyester resins (Union Carbide, Danbury, CT), K-FLEX® XM-2302 and XM-2306 resins (King Industries, Norwalk, CT), CHEMPOL® 11-1369 resin (Cook Composites and Polymers, (Portland, MA), and CYPLEX® 1531 polyester resin (Cytec Industries, West Paterson, NJ). Washington, WI), RHOPLEX® AC-1024 acrylic emulsion resin (Rohm & Haas, Philadelphia, PA), XC® 4005 water-reducible acrylic resin (Cytec Industries, West Paterson, NJ), CRYLCOAT® 3494 solid hydroxy-terminated polyester resin (UCB CHEMICALS USA, Smyrna, GA), RUCOTE® 101 polyester resin (Ruco Polymer, Hicksville, NY), JONCRYL® SCX-800-A and SCX800-B hydroxy-functional solid acrylic resins (SC Johnson & Sons, Racine, WI), and ALFTALAT® AN 745 hydroxy-functional polyester resin, a product of Hoechst Corporation.

[0031] In some embodiments, the hydroxy-functional polymer is a hydroxy-functional polyester (also called a polyester polyol). Suitable polyester polyols include, for example, tridecyl ester polymers prepared from 1,3-benzenedicarboxylic acid, 1,3-dihydro-1,3-dioxo-5-isobenzofurancarboxylic acid, and 2,2-dimethyl-1,3-propanediol.

[0032] In some embodiments, the hydroxy-functional polymer is a hydroxy-functional polyacrylic. An exemplary hydroxy-functional polyacrylic is JONCRYL® 500, which has the following properties: TIFF2025506799000005.tif112149

[0033] The ink vehicle composition may comprise from about 20% to about 80% by weight of the hydroxy-functional polymer, such as from about 30% to about 70% by weight or from about 40% to about 60% by weight.

[0034] The non-volatile diluent is an oligomer and is non-volatile as defined in D2369-20 and herein. Because the non-volatile diluent is an oligomer, it has a low molecular weight compared to the hydroxy-functional polymer. The non-volatile diluent may be a hydrocarbon, glycol, alkylated polyglycol, polyester, aliphatic alcohol, or a combination thereof. The non-volatile diluent can enable high speed offset printing without significant evaporation. For example, the non-volatile diluent can have a boiling point of at least 145°C, such as at least 150°C, at least 160°C, or at least 170°C. In some embodiments, the non-volatile diluent has a boiling point of about 145°C to about 200°C, such as about 145°C to about 190°C or about 150°C to about 185°C. Thus, the non-volatile diluent does not readily evaporate into a gas at room temperature or up to the temperatures used for thermal ink curing.

[0035] As discussed above, the crosslinker compound may be provided in a solvent. In these embodiments, the non-volatile diluent may be exchanged with the solvent and may have a boiling point at least 30° C. higher than the boiling point of the solvent being exchanged, for example, at least 40° C. higher than the boiling point of the solvent being exchanged, at least 50° C. higher than the boiling point of the solvent being exchanged, or at least 60° C. higher than the boiling point of the solvent being exchanged.

[0036] During the curing process, the non-volatile diluent may or may not participate in the crosslinking reaction. Whether the non-volatile diluent participates in the crosslinking reaction depends on whether the non-volatile diluent has a functional group that can react with the crosslinker compound. In some embodiments, the non-volatile diluent reacts with the crosslinker compound during curing. For example, the non-volatile diluent can have a hydroxy functional group, an epoxy functional group, a thiol functional group, an amino functional group, and / or a carboxy functional group. In some embodiments, the non-volatile diluent has at least one hydroxy functional group. In other embodiments, the non-volatile diluent does not react with the crosslinker compound during curing.

[0037] Suitable non-volatile diluents include commercially available polyalkanolamines (Eastman), glycols and polyglycols (BASF, Dow), and aliphatic alcohols (e.g., tridecanol). In some embodiments, the non-volatile diluent is a polyalkylene glycol. The polyalkylene glycol can be synthesized by a ring-opening reaction of an alkylene oxide, such as ethylene oxide or propylene oxide, with an alcohol, such as a glycol. The polyalkylene glycol can be one type of monomer or can include two or more types of monomers. Additionally, the polyalkylene glycol can be alkylated. In some embodiments, the polyalkylene glycol is a polyethylene oxide, a polypropylene oxide, a butoxy-(polyethylene oxide-polypropylene oxide) mixture, or a combination thereof. In some embodiments, the non-volatile diluent is a polyalkylene glycol, a butoxy-(polyethylene oxide-polypropylene oxide) mixture, or a combination thereof.

[0038] The ink vehicle composition may comprise from about 5% to about 30% by weight of a non-volatile diluent, for example from about 5% to about 20% by weight or from about 10% to about 20% by weight.

[0039] In some embodiments, the ink vehicle composition may include about 10% to about 30% by weight of a crosslinker compound, about 40% to about 80% by weight of a hydroxy-functional polymer, and about 5% to about 20% by weight of a non-volatile diluent. An example composition is shown below. TIFF2025506799000006.tif32154

[0040] In some embodiments, the composition comprises a crosslinker compound of formula (I), R 1 , R 2 , and R 3 are independently methyl or n-butyl, a hydroxy-functional polyester as the hydroxy-functional polymer, and a polyalkylene glycol as the non-volatile diluent.

[0041] As mentioned above, butanol is incompatible with heat-curable ink formulations. Thus, the disclosed ink vehicle composition can be used in heat-curable ink compositions and therefore can be substantially free of butanol. For example, the ink vehicle composition can include 2 wt. % or less of butanol, such as 1 wt. % or less, 0.5 wt. % or less, 0.1 wt. % or less, 0.05 wt. % or less, 0.01 wt. % or less, 0.005 wt. % or less, or 0.001 wt. % or less. In some embodiments, the ink vehicle composition includes 0.1 wt. % or less of butanol. In some embodiments, the ink vehicle composition is substantially free of butanol. In some embodiments, the ink vehicle composition is free of butanol.

[0042] In addition, the ink vehicle composition may be substantially free of other volatile solvents, including water and organic solvents such as hydrocarbon, alcohol, ketone, ether, ester, and amide solvents known in the art, hi some embodiments, the composition is free of any volatile solvents.

[0043] The ink vehicle composition may have suitable properties for ink formulation. For example, the ink vehicle composition may be a liquid. Further, the ink vehicle composition may have a viscosity of about 200 to about 500 poise, such as about 250 to about 350 poise. The ink vehicle composition may also have a density of about 8 pounds per gallon to about 12 pounds per gallon, such as about 9, about 9.5, about 10, or about 11 pounds per gallon. In some embodiments, the composition may have a density of about 9.3 pounds per gallon.

[0044] The ink vehicle composition may be in the form of a clear liquid. The ink vehicle composition may have a refractive index of 1.2 or more, such as 1.3 or more, 1.4 or more, 1.5 or more, or 1.6 or more. In some embodiments, the composition has a refractive index of 1.496 or more.

[0045] The combination of the crosslinker compound, the hydroxy-functional polymer, and the non-volatile diluent can impart advantageous stability properties to the ink vehicle composition and the ink itself. For example, the ink vehicle composition can be stable at room temperature for at least 6 months, including at least 12 months, at least 18 months, or at least 24 months. In some embodiments, the ink vehicle composition is stable at room temperature for about 6 months to about 24 months. As described herein, an ink vehicle composition is considered stable for a period of time if no observable change occurs in its physical appearance or chemical properties during that period. Such changes include, for example, decomposition of a component, reaction between different components, precipitation of solid material, layering of components, or color change. The stability of the ink vehicle composition can be measured or evaluated through observation of the composition rheology over time under storage conditions ranging from room temperature to heating, freeze-thawing, etc. (see, for example, ASTM D1849, ASTM D2337, etc.). For example, stability can be demonstrated by no change in viscosity or rheology when maintained at 60° C. or 20° C. when returned to room temperature, and no formation of gel particles.

[0046] (a. Method for Producing Ink Vehicle Composition) The ink vehicle composition can be prepared by a method comprising mixing butanol, a hydroxy-functional polymer, and a crosslinker compound dissolved in a non-volatile diluent to form a mixture, and evaporating at least 98% of the butanol from the mixture to provide the disclosed ink vehicle composition.

[0047] Evaporation can be carried out by heating the mixture under reduced pressure, such as 20 mmHg (torr) or less, 10 mmHg or less, or 5 mmHg or less. Evaporation may be carried out at a temperature of about 55° C. to about 75° C., such as about 60° C., about 65° C., or about 70° C. In some embodiments, evaporation is carried out by heating the mixture at about 60° C. to about 75° C. under a pressure of 20 mmHg or less.

[0048] The amount of butanol remaining in the ink vehicle composition after the evaporation step may be 2% or less of the amount of butanol before evaporation, including 1.5% or less, 1.0% or less, 0.5% or less, 0.1% or less, 0.05% or less, or 0.01% or less.

[0049] (3. Thermosetting ink) In another aspect, the present disclosure provides a thermosetting heat curable ink comprising: (a) the ink vehicle composition described herein; and (b) a colorant.

[0050] The colorant may be a pigment or a dye. The colorant may be a self-dispersing material or may be used in combination with a separate dispersant. In some embodiments, the colorant is a pigment. In general, any pigment may be employed that is compatible with the other components of the ink and thermally stable at the required curing temperatures. The pigment may be cyan, magenta, yellow, black, white, red, orange, violet, blue, green, brown, or a mixture thereof. Examples of pigments may be grouped by their corresponding color index. Pigment Yellow 1, 3, 5, 12, 13, 14, 15, 17, 34, 35, 37, 41, 42, 43, 55, 74, 81, 83, 87, 93, 94, 95, 97, 108, 109, 110, 117, 119, 138, 139, 153, 154, 155, 157, 166, 167, 168, 174, 175, 180, 185, 193, 213, 214, 215, Pigment Red 3, 5, 19, 22, 23, 31, 38, 41, 43, 48:1, 48:2, 48:3, 48:4, 48:5, 49:1, 52, 52:1, 52:2, 53:1, 57:1, 57:2, 58:4, 63:1, 64:1, 81, 81:1, 81:2, 81:3, 81:4, 88, 95, 104, 108, 112, 122, 123, 136, 144, 146, 149, 166, 168, 169, 170, 175, 177, 178, 179, 184, 185, 208, 216, 226, 254, 257, 279, Pigment Blue 1, 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 17:1, 22, 24, 24:1, 27, 28, 29, 36, 60, 61, 62, 63, 75, Pigment Black 7, 9, 10, 28, 34, Pigment White 6, 11, 12, 18, 21, 22, Pigment Orange 4, 5, 13, 16, 20, 34, 36, 64, Pigment Violet 1, 2, 3, 19, 23, 25, 27, 29, 30, 37, 50, Pigment Green 7, 8, 10, 17, 26, 36, and Pigment Brown 3, 5, 25, 26.

[0051] The thermosetting ink may comprise from about 0.1% to about 60% by weight of the ink vehicle composition, such as from about 30% to about 60% by weight or from about 40% to about 60% by weight. Additionally, the thermosetting ink may comprise from about 0.1% to about 50% by weight of the colorant, such as from about 10% to about 60% by weight or from about 20% to about 60% by weight.

[0052] The thermosetting heat-curable ink may further include a lubricant, a viscosity modifier, a tack modifier, a flow modifier, a surfactant, a diluent, or a combination thereof. The thermosetting heat-curable ink may include about 0% to about 5% by weight of a tack modifier. Suitable tack modifiers include, for example, talc, clay, silica, or a combination thereof. The thermosetting heat-curable ink may include about 0% to about 5% by weight of a surfactant. Suitable surfactants include, for example, alkoxylated surfactants. The thermosetting heat-curable ink may include about 0% to about 20% by weight of a viscosity modifier. The thermosetting heat-curable ink may include about 0% to about 5% by weight of a flow modifier. Suitable viscosity modifiers and flow modifiers are known in the art.

[0053] The heat-curable ink can be prepared by mixing the ink vehicle composition described herein, the colorant, and other ingredients. Typically, the ink vehicle composition is metered into a mixing tank. The colorant is then added and dispersed. Diluents and other ingredients may be further added to adjust the viscosity to a desired level.

[0054] Exemplary thermosetting heat curable inks prepared by the methods described herein can be used for printing on any surface that can withstand the temperatures required to cure the thermosetting heat curable ink. Exemplary surfaces include metal surfaces, such as aluminum surfaces. Exemplary thermosetting heat curable inks can exhibit the following physical properties: · Tack, 1 ft., 90°F (32.2°C) @ 1200 rpm o 8.0 - 21.0 ± 1 (ink) o 14.0~25.0±1 (base material), · grind o < 3 NPIRI <7.5 microns · Laray viscosity, 25℃ o 50±20 poise.

[0055] The thermosetting inks described herein may be stable at room temperature for at least 6 months, including at least 12 months, at least 18 months, or at least 24 months. In some embodiments, the thermosetting heat curable inks are stable at room temperature for about 6 months to about 24 months. The thermosetting heat curable inks can be maintained free of thermal or air oxidation induced discoloration. Crosslinking reactions may not occur in the inks of the present invention until sufficient activation energy is applied during the curing cycle (e.g., in a baked enamel oven). The inks of the present invention can avoid pigment precipitation during storage and use.

[0056] (4. Printing) In another aspect, the present disclosure provides a method of printing an ink onto a substrate, the method comprising applying a thermosetting heat curable ink as described herein to a surface of the substrate and heating the applied ink, thereby curing the applied ink. Curing can typically be accomplished without the use of a catalyst. Additionally, the cured film and / or ink can exhibit useful hardness, chemical resistance, exterior durability, and environmental etch resistance.

[0057] Heating may be carried out at a temperature of at least 150° C., including at least 170° C., at least 190° C., or at least 210° C. In some embodiments, heating is carried out at about 180° C. to about 200° C., such as about 185° C., about 190° C., or about 195° C.

[0058] The substrate can be any substrate capable of withstanding the temperatures required to cure the thermosetting heat curable ink. For example, the substrate can include a metal surface or be made of metal. Suitable substrates include industrial or consumer containers, such as beverage or food containers. In some embodiments, the substrate is a metal container, such as an aluminum can for holding beverages or food.

[0059] In some embodiments, the thermosetting heat curable inks of the present invention are used in high speed offset printing processes to provide printed images or decorations on metal surfaces. Suitable processes include those performed under applicable standards set forth by the National Printing Ink Research Institute (NPIRI). In a typical high speed offset printing process, ink is transferred from individual color (pigment) ink wells to a lithographic printing plate having ink-receptive image areas. The process is carried out in a rotating system, sometimes with a thin metal plate wrapped around a cylinder. The ink image is transferred from the plate to a "blanket" (an intermediate cylinder covered with a rubber layer) and then transferred to the substrate surface. For printing aluminum cans, printing can proceed at high speeds of about 1000 to about 2000 cans per minute (cpm).

[0060] 5. Working Examples Example 1 - Preparation of Ink Vehicle Composition R 1 , R 2 , and R 3 The TACT-based crosslinker solids of formula (I), where each independently is methyl or n-butyl, were mixed in about 50% by weight mixture of butanol (15.5 parts by weight), polyester polyol (49.5 parts by weight), and polyalkylene glycol non-volatile diluent (35 parts by weight). At least 98% of the butanol was removed from the mixture using rotary evaporation at 65° C. under a vacuum of about 20 torr.

[0061] The resulting composition was stored at room temperature for two years, but no precipitation was observed.

[0062] Example 2 - Preparation of Thermosetting Ink A heat-curable ink was prepared according to the formulation. TIFF2025506799000007.tif41148

[0063] (Example 3 - Printing on aluminum cans) The ink prepared in Example 2 was printed onto aluminum cans using a high speed offset printing process, and the ink on the printed cans was cured in a baking oven at a temperature of 193°C (380°F).

[0064] For completeness, various aspects of the invention are set out in the following numbered paragraphs.

[0065] (Item 1)R 1 , R 2 , and R 3 are independent C 1-10 a crosslinker compound of formula (I) which is alkyl; [ka] a hydroxy-functional polymer; a non-volatile diluent; An ink vehicle composition that is substantially butanol-free.

[0066] (Item 2)R 1 , R 2 , and R 3 are independent, C 1-4 2. The composition according to claim 1, wherein the alkyl is alkyl.

[0067] (Item 3) The composition according to item 1 or 2, wherein the crosslinker compound is present in an amount of about 10% by weight to about 90% by weight of the composition.

[0068] (Item 4) The composition according to any one of items 1 to 3, wherein the hydroxy-functional polymer is selected from the group consisting of hydroxy-functional polyesters, hydroxy-functional polyacrylics, hydroxy-functional polyurethanes, and combinations thereof.

[0069] (Item 5) The composition according to any one of items 1 to 4, wherein the hydroxy-functional polymer is in an amount of about 20% to about 80% by weight of the composition.

[0070] (Item 6) The composition according to any one of Items 1 to 5, wherein the non-volatile diluent is selected from the group consisting of hydrocarbons, glycols, polyalkylene glycols, polyesters, and combinations thereof.

[0071] (Item 7) The composition according to any one of Items 1 to 6, wherein the non-volatile diluent is in an amount of about 5% to about 30% by weight of the composition.

[0072] (Item 8) The composition according to any one of Items 1 to 7, having a viscosity of about 200 to about 500 poise.

[0073] (Item 9) The composition according to any one of Items 1 to 8, wherein the composition is stable at room temperature for about 6 to about 24 months.

[0074] (Item 10)R 1 , R 2 , and R 3is each independently methyl or n-butyl, the hydroxy-functional polymer is a hydroxy-functional polyester, and the non-volatile diluent is a polyalkylene polyglycol.

[0075] Item 11. A method for preparing an ink vehicle composition, comprising: R 1 , R 2 , and R 3 are independent C 1-10 dissolving and mixing a crosslinker compound of formula (I), which is an alkyl, in butanol, a hydroxy-functional polymer, and a non-volatile diluent to form a mixture; [ka] and evaporating at least 98% of the butanol from the mixture to provide the composition of claim 1.

[0076] 12. The method of claim 11, wherein the evaporation comprises heating the mixture at a temperature of about 65° C. under a pressure of 20 mmHg (torr) or less.

[0077] (Item 13) A thermosetting heat-curable ink comprising: (a) the ink vehicle composition according to any one of Items 1 to 10; and (b) a colorant.

[0078] (Item 14) The heat-curable heat-curable ink according to item 13, wherein the ink is stable at room temperature for at least six months.

[0079] 15. The thermosetting ink according to claim 13, wherein the ink vehicle composition is in an amount of about 30% to about 60% by weight of the ink.

[0080] (Item 16) The thermosetting ink according to any one of Items 13 to 15, wherein the colorant is present in an amount of about 10% to about 60% by weight of the ink.

[0081] (Item 17) The thermosetting ink according to any one of items 13 to 16, further comprising a lubricant, a viscosity modifier, a tack modifier, a flow modifier, a surfactant, a diluent, or a combination thereof.

[0082] (Item 18) A method for printing ink on a substrate, the method comprising: applying the thermosetting ink according to any one of Items 13 to 17 to a surface of a substrate; and curing the applied thermosetting ink by heating the applied thermosetting ink.

[0083] 19. The method of claim 18, wherein the surface is a metal surface.

[0084] (Item 20) The method according to item 18 or 19, wherein the substrate is a container.

[0085] Various features, advantages, and embodiments are set forth in the following claims.

Claims

1. R １ , R ２ , and R ３ are independent C １－1０ a crosslinker compound of formula (I) which is alkyl; 【Chemistry 1】 a hydroxy-functional polymer; a non-volatile diluent; An ink vehicle composition that is substantially butanol-free.

2. R １ , R ２ , and R ３ are independent C １－４ The composition of claim 1 wherein the alkyl group is an alkyl group.

3. The composition of claim 1, wherein the crosslinker compound is in an amount of from about 10% to about 90% by weight of the composition.

4. 10. The composition of claim 1, wherein the hydroxy-functional polymer is selected from the group consisting of hydroxy-functional polyesters, hydroxy-functional polyacrylics, hydroxy-functional polyurethanes, and combinations thereof.

5. The composition of claim 1, wherein the hydroxy-functional polymer is in an amount of about 20% to about 80% by weight of the composition.

6. 10. The composition of claim 1, wherein the non-volatile diluent is selected from the group consisting of hydrocarbons, glycols, polyalkylene glycols, polyesters, and combinations thereof.

7. The composition of claim 1, wherein the non-volatile diluent is in an amount of from about 5% to about 30% by weight of the composition.

8. The composition of claim 1 having a viscosity of about 200 to about 500 poise.

9. The composition of claim 1, wherein the composition is stable at room temperature for about 6 to about 24 months.

10. R １ , R ２ , and R ３ 2. The composition of claim 1, wherein each independently is methyl or n-butyl, the hydroxy-functional polymer is a hydroxy-functional polyester, and the non-volatile diluent is a polyalkylene polyglycol.

11. 1. A method for preparing an ink vehicle composition comprising: R １ , R ２ , and R ３ are independent C １－1０ dissolving and mixing a crosslinker compound of formula (I), which is an alkyl, in butanol, a hydroxy-functional polymer, and a non-volatile diluent to form a mixture; 【Chemistry 1】 and evaporating at least 98% of the butanol from the mixture to provide the composition of claim 1.

12. 12. The method of claim 11, wherein the vaporizing comprises heating the mixture at a temperature of about 65°C under a pressure of 20 mmHg (torr) or less.

13. (a) the ink vehicle composition of claim 1; (b) a colorant.

14. The thermosetting heat curable ink of claim 13 , wherein the ink is stable at room temperature for at least six months.

15. The thermosetting heat curable ink of claim 13, wherein the ink vehicle composition is in an amount of from about 30% to about 60% by weight of the ink.

16. The thermosetting heat curable ink of claim 13, wherein the colorant is in an amount of from about 10% to about 60% by weight of the ink.

17. 14. The thermosetting ink of claim 13, further comprising a lubricant, a viscosity modifier, a tack modifier, a flow modifier, a surfactant, a diluent, or a combination thereof.

18. 1. A method of printing an ink onto a substrate, comprising: Applying the heat-curable ink according to claim 13 to a surface of a substrate; and curing the applied thermosetting ink by heating the applied thermosetting ink.

19. The method of claim 18 , wherein the surface is a metal surface.

20. The method of claim 18 , wherein the substrate is a container.

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