Primer compositions and related methods for liquid electrophotographic printing

Abstract

A primer coating for liquid electrophotographic printing may comprise: an aqueous fluid; about 50% to about 90% by weight of a coating material, based on total dissolved or dispersed solids, the coating material comprising rosin acid and an acid-functionalized vinyl copolymer with an acid value of about 110 mg KOH / g or lower; and about 10% to about 50% by weight of a coating enhancer comprising polyurethane, based on total dissolved or dispersed solids. The acid-functionalized vinyl copolymer and rosin acid may be at least partially neutralized with a base comprising at least one amine.

Description

Background Technology

[0001] On-demand digital printing presses based on liquid electrophotographic systems are widely used in modern laser printing and copier systems. Liquid electrophotographic printing systems form a latent image on a photosensitive drum, and then a liquid toner (ink) is applied to the latent image on the drum to form a physical image for subsequent transfer to a base substrate. HP ELECTROINK (ethylene / acrylic copolymer composition) is an example of a commonly used liquid ink system. Printers using such liquid electrophotographic inks are commercially available from the Hewlett-Packard Company under the trade name HP INDIGO. After ink exposure, the latent image is then electrotransferred to an intermediate transfer blanket or tape for printing onto a base substrate such as paper or polymer film.

[0002] Although liquid electrophotographic printing can achieve high image quality, the transferred image often does not adhere well to the base substrate unless the substrate is pre-treated with a suitable primer composition to form a primer coating. Primer coatings are typically chosen to include functional groups that promote robust chemical interactions between complementary functional groups in both the base substrate and the ink, thereby facilitating strong image adhesion to the base substrate surface. In practice, achieving strong adhesion of the primer coating to both the base substrate and the ink can be difficult in some cases. In some cases, differential adhesion to different ink colors may also occur. Attached Figure Description

[0003] not applicable. Detailed Implementation

[0004] This disclosure generally relates to primer compositions for liquid electrophotographic printing, and more specifically, to primer compositions and base substrates coated thereon, wherein at least partially neutralized rosin acid is present.

[0005] As mentioned above, liquid electrophotography is a very powerful imaging technique. However, transferring liquid electrophotographic images onto different substrates can be problematic due to poor image adhesion to the base substrate. Primer coatings can be used to improve image adhesion to the base substrate, but even with primer coatings, it remains difficult to achieve robust adhesion of the primer coating to the surface of the base substrate and to the electrophotographed image on it.

[0006] This disclosure provides a primer composition and a primer coating formed therefrom, which overcome the aforementioned difficulties. Specifically, the primer composition disclosed herein comprises a coating material containing rosin acid and an acid-functionalized ethylene copolymer with an acid value of about 110 mg KOH / g or lower, wherein the acid-functionalized ethylene copolymer and the rosin acid are at least partially neutralized with a base containing at least one amine. Polyurethane may be further incorporated into the primer composition and the primer coating to promote adhesion.

[0007] The primer compositions described herein can be readily formulated using commercially available (or synthetically prepared) polymers, rosin acids, and amine bases. The ternary combination of the acid-functionalized ethylene copolymer, rosin acid, and polyurethane offers numerous advantages regarding the formation of the primer coating. Rosin acid promotes robust adhesion of the coating material to the substrate surface. Furthermore, rosin acid acts as an effective co-dispersant, promoting at least partial dispersion or dissolution of the acid-functionalized ethylene copolymer when combined with the base. In the absence of rosin acid, effective dispersion or dissolution of the acid-functionalized ethylene copolymer may not be achieved when the acid value is about 110 mg KOH / g polymer or lower. For this reason, it is more conventional to use acid-functionalized ethylene copolymers with an acid value of about 115 mg KOH / g polymer or higher in the primer coating, as such copolymers dissolve or disperse more effectively. Depending on the degree of neutralization, the coating material (the combination of the acid-functionalized ethylene copolymer and rosin acid) can be dissolved and / or emulsified in an aqueous fluid. For example, in cases of incomplete (partial) neutralization, at least a portion of the acid-functionalized ethylene copolymer and / or rosin acid may be emulsified or dispersed as a solid in an aqueous fluid. In contrast, when fully neutralized, the acid-functionalized ethylene copolymer and rosin acid may be dissolved as a colloidal solution in an aqueous fluid. When combined with the coating material in an aqueous fluid, the polyurethane may be provided as an aqueous emulsion, and the final primer composition may remain in an emulsified form, wherein the polyurethane and optionally the acid-functionalized ethylene copolymer and / or rosin acid may also be emulsified. The acid-functionalized ethylene copolymer and rosin acid may be provided as a first aqueous dispersion, and the polyurethane as a second aqueous dispersion, which in some cases are combined together to form the primer composition.

[0008] Advantageously, polyurethane can synergistically interact with the coating material to increase its compatibility with the base substrate surface and improve its adhesion. In the absence of polyurethane, the coating material may lack sufficient stability to withstand liquid electrophotographic printing thereon. Specifically, in the absence of polyurethane, the coating material may have a greater affinity for liquid electrophotographic inks and be at least partially removed during the liquid electrophotographic printing process.

[0009] The primer compositions disclosed herein can form a robust primer coating on a base substrate, wherein the primer coating is particularly effective in promoting the adhesion of HP INDIGO liquid electrophotographic inks. Ink adhesion can be determined relatively using a tape pull test, such as that specified in ASTM F 2252 / F 2252M, and further described herein in modified form. Advantageously, the primer coatings described herein promote easy adhesion of different colors of HP INDIGO inks, which is not necessarily the case with other types of primer coatings.

[0010] Therefore, the primer compositions disclosed herein may comprise an aqueous fluid; about 50% to about 90% by weight of a coating material based on total dissolved or dispersed solids, said coating material comprising rosin acid and an acid-functionalized ethylene copolymer with an acid value of about 110 mg KOH / g or lower, said acid-functionalized ethylene copolymer and said rosin acid being at least partially neutralized with a base comprising at least one amine; and about 10% to about 50% by weight of a coating enhancer comprising polyurethane based on total dissolved or dispersed solids. The primer compositions disclosed herein are particularly suitable for forming a primer coating on a base substrate, which is then used for liquid electrophotographic printing.

[0011] The aqueous fluid used in this disclosure may comprise water or water mixed with a water-miscible organic solvent (e.g., an alcohol or glycol). The aqueous fluid and the primer composition formed therefrom may be neutral or alkaline, depending on the specific application requirements. A specific pH may be selected to maintain the acid-functionalized vinyl copolymer and rosin acid in at least a partially neutralized form, which determines whether the acid-functionalized vinyl copolymer and rosin acid dissolve, disperse, and / or emulsify in the aqueous fluid. In other instances, the pH of the aqueous fluid or the primer composition formed therefrom may be selected to provide a specific protonated state for one or more additional components of the primer composition, examples of which are further discussed below. For example, buffering may be performed if desired or necessary. Therefore, the aqueous fluid and the primer composition formed therefrom may have a pH of about 7 to about 8, or about 7 to about 14, or about 8 to about 14, or about 8 to about 12, or about 7 to about 9, or about 7.5 to about 9.5, or about 7.5 to about 11, or about 8 to about 10.5.

[0012] For example, solids emulsified or dispersed in colloidal form in a primer composition may exhibit particle sizes of about 10 μm or smaller, or about 5 μm or smaller, such as about 10 nm to about 50 μm, or about 50 nm to about 5 μm, or about 100 nm to about 5 μm.

[0013] The aqueous fluid may be present in the primer composition disclosed herein in an amount of up to about 90% by weight, or up to about 80% by weight, or up to about 70% by weight, or up to about 60% by weight, or up to about 50% by weight, or up to about 40% by weight, or up to about 30% by weight, or up to about 20% by weight, or up to about 15% by weight, for example, about 5% by weight to about 20% by weight, or about 10% by weight to about 25% by weight, or about 10% by weight to about 30% by weight, or about 15% by weight to about 25% by weight, or about 50% by weight to about 80% by weight, each measured based on the total mass of the primer composition. The balance of the primer composition may contain dissolved, dispersed, and / or emulsified solids, which include at least the acid-functionalized vinyl copolymer, rosin acid, and polyurethane, and optionally additional components. The amount of aqueous fluid may be selected to promote effective dispersion of the solids. For example, in a primer composition containing 60% by weight of an aqueous fluid, the mass balance of the primer composition may contain 40% by weight of solids, which may include at least the acid-functionalized ethylene copolymer, rosin acid, and polyurethane, wherein the amount of the aqueous fluid may be selected to maintain the solids in a desired state after at least partial neutralization of the coating material.

[0014] The acid-functionalized ethylene copolymer may comprise ethylene and one or more acidic monomers, preferably at least one or more (meth)acrylic acid monomers. The term "(meth)acrylic acid" is used herein to refer equivalently to acrylic acid and methacrylic acid, and their derivatives. Thus, in various instances, the acid-functionalized ethylene copolymer may comprise an ethylene-(meth)acrylic acid copolymer. Other suitable acidic monomers that may be present in the acid-functionalized ethylene copolymer (either as a substitute for or complement to (meth)acrylic acid) include olefinically unsaturated compounds containing carboxylic acids, such as maleic acid, methyl maleate, ethyl maleate, itaconic acid, fumaric acid, crotonic acid, and citraconic acid. Suitable olefinically unsaturated monomers containing sulfonic acid groups that may be present include, for example, styrene sulfonic acid. Any of the foregoing alternatives to (meth)acrylic acid monomers present in the acid-functionalized ethylene copolymer and / or in combination with (meth)acrylic acid monomers in the ethylene-acrylic acid copolymer.

[0015] In addition to ethylene, other olefinically unsaturated monomers may also be present in the acid-functionalized ethylene copolymer. Exemplary examples of such monomers may include, for example, (meth)acrylates, (meth)acrylamide, styrene or its substituted variants, dienes such as 1,3-butadiene or isoprene; vinyl esters such as vinyl acetate, vinyl alkylates or their derivatives, (meth)acrylonitrile, olefinically unsaturated halides such as vinyl chloride, α-olefins or any combination thereof. When present, α-olefins that may be incorporated into the acid-functionalized ethylene copolymer include, but are not limited to, propylene, isobutene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene or combinations thereof.

[0016] Suitable ethylene-(meth)acrylic acid copolymers for use in the coating materials may comprise about 5% to about 20% by weight, or about 8% to about 17% by weight, or about 9% to about 15% by weight, or about 8% to about 12% by weight, or about 12% to about 16% by weight of (meth)acrylic acid monomer units based on the total mass of the (meth)acrylic acid copolymer, and the remainder of the (meth)acrylic acid copolymer comprises ethylene monomer units and other monomer units lacking acid groups (if present). For example, one or more monomer units that are not (meth)acrylic acid monomer units may comprise at least one α-olefin. Thus, in some instances, the acid-functionalized ethylene copolymer may comprise an ethylene-(meth)acrylic acid copolymer, wherein the amount of the (meth)acrylic acid monomer units may be selected according to the above ranges.

[0017] Commercially available examples of suitable ethylene-(meth)acrylic acid copolymers may include, for example, NUCREL® 699 (Dow) and similar resins, ESCOR® 5100 (ExxonMobil) and similar resins, etc.

[0018] In non-limiting examples, the melt flow index (MFI) of the ethylene-methacrylic acid copolymer at 2.16 kg and 190°C may be about 5 to about 500 g / 10 min; or about 20 to about 400 g / 10 min (2.16 kg, 190°C); or about 50 to about 400 g / 10 min (2.16 kg, 190°C); or about 50 to about 300 g / 10 min (2.16 kg, 190°C); or about 150 to about 300 g / 10 min (2.16 kg, 190°C). The MFI value may be measured according to ASTM D1238. Other acid-functionalized ethylene copolymers may also have MFI values ​​within a similar range.

[0019] In non-limiting examples, the acid value of the ethylene-methacrylic acid copolymer may be about 110 mg KOH / g or less, or about 100 mg KOH / g or less, or about 90 mg KOH / g or less, or about 80 mg KOH / g or less. The acid value can be measured by titration or calculated based on the known amount of acid-containing monomer units in the ethylene-methacrylic acid copolymer. Other acid-functionalized ethylene copolymers may also have acid values ​​in similar ranges. The minimum acid value can be selected based on the ability of the acid-functionalized ethylene copolymer to disperse in an aqueous fluid in the presence of a selected amount of rosin acid.

[0020] Rosin acids can promote the adhesion of the coating material to the base substrate and promote the dispersion of the acid-functionalized ethylene copolymer. Suitable rosin acids may include compounds such as abietics (e.g., abietic acid), piperidine (e.g., piratic acid), or any combination thereof. Other suitable rosin acids that may exist alone or in combination with abietic acid and / or piratic acid include, for example, neoabietic acid, dehydroabietic acid, dihydroabietic acid, tetrahydroabietic acid, longleaf abietic acid, santalinic acid, and δ-abietic acid. 8 - Piperine, δ 8 -Isopipolonic acid, L-pipolonic acid, isopiratic acid, 7,15-pimaradienoic acid, or any combination thereof. Any of the aforementioned rosin acids or any other rosin acids used in the primer compositions and primer coatings of this disclosure may optionally be (fully or partially) hydrogenated. Hydrogenated rosin acids may at least partially deplete aliphatic carbon-carbon double bonds, and preferably may be free of aliphatic carbon-carbon double bonds. In non-limiting examples, said one or more rosin acids may be derived from resin rosin and may be substantially free of liquid terpenes after release from resin rosin. In some cases, crude resin rosin lacking liquid terpenes may be used directly as a source of said one or more rosin acids.

[0021] Natural sources of rosin acid may include, but are not limited to, oleoresins, tall oils, rosin or resinous rosin derived from tree and plant extrusions, wood extracts, and certain tackifying resins. Wood extracts include, but are not limited to, terpenoids, including polymers made from monoterpenoids (e.g., α-pinene, β-pinene, and dipentene), sesquiterpenoids, and diterpenoids (including labdane compounds). Any of the foregoing substances may be hydrogenated or partially hydrogenated.

[0022] A suitable rosin acid is FORAL AX-E (Eastman), which is hydrogenated wood rosin. Other suitable rosin acids include TACOLYN™ resins (Eastman), such as TACOLYN™ 1100, 3166, or 4187. Other commercially available examples of suitable rosin acids may include STAYBELITE (Eastman, partially hydrogenated rosin) and DYMEREX (Eastman, dimerized rosin).

[0023] In non-limiting examples, the acid value of the abietic acid may be about 120 mg KOH / g abietic acid or higher, or about 150 mg KOH / g abietic acid or higher, or about 160 mg KOH / g abietic acid or higher, or about 170 mg KOH / g abietic acid or higher, for example, about 130 mg KOH / g abietic acid - about 180 mg KOH / g abietic acid, or about 135 mg KOH / g abietic acid - about 170 mg KOH / g abietic acid, or about 130 mg KOH / g abietic acid - about 160 mg KOH / g abietic acid, or about 145 mg KOH / g abietic acid - about 170 mg KOH / g abietic acid, or about 160 mg KOH / g abietic acid - about 170 mg KOH / g abietic acid. The acid value can be determined as described above.

[0024] In the primer compositions and primer coatings disclosed herein, the acid groups of the acid-functionalized ethylene copolymer and rosin acid are at least partially neutralized, including complete or partial neutralization. Upon complete neutralization, substantially all of the rosin acid is converted to the corresponding rosin salt (e.g., abirate, pirarate, etc.), and the acid groups of the acid-functionalized ethylene copolymer are converted to the corresponding salts. Upon partial neutralization, a first portion of the rosin acid and / or the acid-functionalized ethylene copolymer is converted to rosin salts and / or salts, and a second portion of the rosin acid and / or the acid-functionalized ethylene copolymer remains in the form of a free carboxylic acid. In a non-limiting example, at least about 20%, or at least about 30%, or at least about 40%, or at least about 50%, or at least about 60%, or at least about 70%, or at least about 80%, or at least about 90% of the rosin acid and acid-functionalized ethylene copolymer are neutralized with a base, determined based on the molar ratio of neutralized carboxylic acid groups in the acid-functionalized ethylene copolymer and rosin acid to the total carboxylic acid groups in the acid-functionalized ethylene copolymer and rosin acid. In a more specific example, partial neutralization may include neutralizing about 50% to about 95%, or about 60% to about 95%, or about 70% to about 90%, or about 75% to about 95%, or about 80% to about 95%, or about 90% to about 99% of carboxylic acid groups in the rosin acid and acid-functionalized ethylene copolymer, measured relative to the total carboxylic acid groups in the rosin acid and acid-functionalized ethylene copolymer. Preferably, the acid-functionalized ethylene copolymer and rosin acid can be completely neutralized with a base containing at least one amine. Optionally, the base may comprise a mixture of ammonia and at least one amine.

[0025] When the coating material is completely neutralized, at least a stoichiometric amount of base may be present relative to the total molar amount of carboxylic acid groups present. Optionally, an excess of base beyond what is required to completely neutralize the acid groups in the coating material may be included. Thus, in some instances, the acid-functionalized vinyl copolymer and rosin acid may be completely converted to their respective salt forms, and an excess of base may remain present in the aqueous fluid, for example, an excess of at least one amine. The amount of excess amine may be about 5% or more, or about 10% or more, or about 20% or more, or about 50% or more, each measured on a molar basis.

[0026] When the abietic acid is completely or mostly neutralized, it is soluble in the aqueous fluid. For example, it is soluble in the aqueous fluid when at least about 80% or more, or about 85% or more, or about 90% or more, or about 95% or more, or about 97% or more, or about 99% or more are neutralized. When the abietic acid is not completely neutralized or insufficient amounts are converted to the corresponding salt form, at least a portion of the abietic acid can be dispersed as multiple solid particles in the aqueous fluid. The dispersion of abietic acid as multiple solid particles in the aqueous fluid can be achieved by means of at least one surfactant, examples of which are further discussed below. In some cases, the solid particles can be emulsified in the aqueous fluid.

[0027] Similarly, the acid-functionalized ethylene copolymer can be dissolved, dispersed, and / or emulsified, depending on the degree of neutralization with alkali. Neutralization can occur in amounts similar to those specified above for rosin acid. When completely neutralized, the acid-functionalized ethylene copolymer can be dispersed as a colloidal solid in an aqueous fluid.

[0028] A suitable base for at least partially neutralizing the rosin acid and / or acid-functionalized ethylene copolymer may include at least one amine. Suitable amines may include, but are not limited to, ethanolamine, diethanolamine, triethanolamine, dimethylethanolamine, diethylethanolamine, trimethylamine, diethylamine, dimethylethylamine, triethylamine, 2-amino-2-methylprop-1-ol, 2-dimethylamino-2-methyl-1-propanol, etc. Optionally, in addition to the at least one amine, the base may also contain ammonia. When combined with the rosin acid and acid-functionalized ethylene copolymer to promote at least partial neutralization, any of the aforementioned amines may be present in an aqueous fluid. Alternatively, a suitable amine may be combined with the rosin acid and acid-functionalized ethylene copolymer in pure form. Suitable pH ranges after at least partial neutralization of the rosin acid and acid-functionalized ethylene copolymer are provided above. In more specific examples, the base may contain at least one amine, ammonia, or any combination thereof, preferably at least one amine without ammonia. More preferably, the base may not include a permanent base, such as a hydroxide base.

[0029] The acid-functionalized ethylene copolymer and rosin acid can be present in the coating material in any suitable ratio to promote adhesion to the base substrate on which liquid electrophotographic printing is performed. Furthermore, the amount of rosin acid relative to the acid-functionalized ethylene copolymer can be selected to promote the dispersion of the latter. In a non-limiting example, the acid-functionalized ethylene copolymer may be present in the coating material in a greater amount than rosin acid. In a non-limiting example, the coating material may contain about 60% by weight or more, or about 70% by weight or more, or about 80% by weight or more, or about 90% by weight or more of the acid-functionalized ethylene copolymer, and about 10% by weight or less, or about 20% by weight or less, or about 30% by weight or less, or about 40% by weight or less of rosin acid, wherein the rosin acid is present in the coating material in a non-zero amount. Preferably, the amount of rosin acid may be about 5% by weight or higher, or about 10% by weight or higher, or about 15% by weight or higher, or about 20% by weight or higher, or about 25% by weight or higher, or about 30% by weight or higher, or about 35% by weight or higher, or about 40% by weight or higher, wherein the acid-functionalized ethylene copolymer constitutes the balance of the coating material and is present in a greater amount than rosin acid. Each of the foregoing weight percentage values ​​is measured relative to the combined amount of acid-functionalized ethylene copolymer and rosin acid in the coating material.

[0030] In some or other non-limiting examples, the coating material may comprise about 50% to about 90% by weight of an acid-functionalized ethylene copolymer and about 10% to about 50% by weight of rosin acid, or about 60% to about 80% by weight of an acid-functionalized ethylene copolymer and about 20% to about 40% by weight of rosin acid, or about 50% to about 70% by weight of an acid-functionalized ethylene copolymer and about 30% to about 50% by weight of rosin acid, or about 50% to about 60% by weight of an acid-functionalized ethylene copolymer and about 30% to about 50% by weight of rosin acid, or about 50% to about 60% by weight of an acid-functionalized ethylene copolymer and about 50% to about 60% by weight of rosin acid. About 40% to about 50% by weight of rosin acid, or about 60% to about 70% by weight of acid-functionalized ethylene copolymer and about 30% to about 40% by weight of rosin acid, or about 70% to about 80% by weight of acid-functionalized ethylene copolymer and about 20% to about 30% by weight of rosin acid, or about 80% to about 90% by weight of acid-functionalized ethylene copolymer and about 10% to about 20% by weight of rosin acid, each based on the combined amount of acid-functionalized ethylene copolymer and rosin acid in the coating material.

[0031] The polyurethane in the coating enhancer can enhance the interaction between the coating material and the base substrate and improve the adhesion of inks to it. Polyurethanes are particularly suitable coating enhancers because they can be readily prepared into aqueous emulsions for use in combination with coating materials. According to some examples, suitable polyurethanes are aliphatic polyurethanes. Some such polyurethanes are elastomers and include “hard” segments and “soft” segments, which can be regiocrystalline and regioamorphous, respectively. The polyurethane can be a reaction product of diisocyanate, polyol, and optionally chain extender. A suitable aliphatic polyurethane is NEOREZ® R-600 (Covestro). Other suitable aliphatic polyurethanes may include INCOREZ 217 (Industrial Copolymer Ltd.).

[0032] Examples of suitable polyurethanes include, but are not limited to, polyether polyurethanes, polyester polyurethanes, blends of polyether and polyester polyurethanes, and any combination thereof. Examples of suitable polyurethanes may include, but are not limited to, poly[4,4'-methylene bis(phenyl isocyanate)-alt-1,4-butanediol / di(propylene glycol) / polycaprolactone], ELASTOLLAN® 1190A (polyether polyurethane elastomer, sourced from BASF), ELASTOLLAN® 1190A10 (polyether polyurethane elastomer, sourced from BASF), NEOREZ R 605 and other NEOREZ resins (Covestro), INCOREZ 217 (Industrial Copolymer Ltd.), and any combination thereof.

[0033] In a non-limiting example, the primer composition may comprise about 50% to about 90% by weight of coating material and about 10% to about 50% by weight of coating enhancer, or about 60% to about 80% by weight of coating material and about 20% to about 40% by weight of coating enhancer, or about 50% to about 70% by weight of coating material and about 30% to about 50% by weight of coating enhancer, or about 50% to about 60% by weight of coating material and about 40% to about 50% by weight of coating enhancer, or about 60% to about 70% by weight of coating material and about 30% to about 40% by weight of coating enhancer. The coating enhancer is expressed as a percentage by weight, or as much as 70% to 80% by weight of the coating material and about 20% to 30% by weight of the coating enhancer, or as much as 80% to 90% by weight of the coating material and about 10% to 20% by weight of the coating enhancer, or as much as 65% to 75% by weight of the coating material and about 25% to 35% by weight of the coating enhancer, or as much as 75% to 85% by weight of the coating material and about 15% to 25% by weight of the coating enhancer, each based on the combined amount of coating material and coating enhancer in the primer composition or the primer coating formed therefrom. The combined amount of coating material, coating enhancer, and any optional components represents the total solids combined with the aqueous fluid or the total solids formed after the primer coating is deposited.

[0034] Therefore, based on the above range, the primer composition and the primer coating formed therefrom may contain the acid-functionalized ethylene copolymer, rosin acid, and polyurethane in the following range of individual weight percentage values, each based on the combined amount of the acid-functionalized ethylene copolymer, rosin acid, and polyurethane present in the aqueous fluid (total solids):

[0035] - Acid-functionalized ethylene copolymer: approximately 25% by weight to approximately 81% by weight;

[0036] -Rosin acid: approx. 5% - approx. 45% by weight; and

[0037] - Polyurethane: Approximately 10% by weight - Approximately 50% by weight.

[0038] Within the foregoing scope or any sub-scope, each component may be in a dissolved form (including colloidal form), a dispersed form, an emulsified form, or any combination thereof, depending on the degree of neutralization and the natural solubility of the acid-functionalized vinyl copolymer, rosin acid, and polyurethane in an aqueous fluid. In more specific examples, when combined in an aqueous fluid, the acid-functionalized vinyl copolymer, rosin acid, and polyurethane may collectively define an aqueous emulsion. In some examples, at least the polyurethane may be emulsified in an aqueous fluid. In some or other examples, the coating material or a portion thereof may be soluble in the aqueous fluid, and the polyurethane may be emulsified in the aqueous fluid.

[0039] The primer compositions described herein may contain a high total solids loading. In exemplary embodiments, the primer compositions described herein may contain about 5% to about 90% by weight of total solids, or about 5% to about 80% by weight of total solids, or 5% to about 70% by weight of total solids, or about 5% to about 60% by weight of total solids, or about 10% to about 60% by weight of total solids, or about 15% to about 60% by weight of total solids, or about 15% to about 55% by weight of total solids, or about 20% to about 50% by weight of total solids, or about 35% to about 55% by weight of total solids, based on the total mass of the primer composition.

[0040] In addition to the acid-functionalized ethylene copolymer, rosin acid, and polyurethane, other components may optionally be present in the primer compositions and primer coatings of this disclosure. Exemplary components that may optionally be present are discussed below.

[0041] In some embodiments, the primer compositions of this disclosure may further comprise surfactants or other suitable wetting agents. Suitable surfactants may include, for example, neutral surfactants, zwitterionic surfactants, cationic surfactants, anionic surfactants, or any combination thereof. When present, the total amount of these types of surfactants in the primer compositions of this disclosure may be from about 0.1 wt% to about 20 wt%, or from about 0.1 wt% to about 5.0 wt%, or from about 0.5 wt% to about 2.5 wt%, based on total solids.

[0042] Suitable neutral surfactants may include, for example, alkylaryl polyether alcohols, alkylphenol ethoxylates, alkyl ethoxylates, polyvinyl sorbitol fatty acid esters, poloxamer, fatty acid esters, fatty acid glycerides, fatty acid sorbitol esters, and any combination thereof. Other suitable neutral surfactants may include, for example, emulsifiers such as lecithin or glycerides, or polymeric colloids such as polyvinyl alcohol, polyvinylpyrrolidone, hydroxyethyl cellulose, and other cellulose derivatives. Amphoteric surfactants disclosed herein may include, for example, betaine and sulfobetaine.

[0043] Suitable anionic surfactants for use in the present invention may include, for example, alkyl ethoxylate sulfates and sulfonates, alkylphenol ethoxylate sulfates and sulfonates, alkyl sulfates, alkyl sulfonates, alkyl aryl sulfonates, sulfosuccinates, and mixtures thereof. Other anionic surfactants suitable for the primer compositions disclosed herein include, for example, carboxylates of long-chain fatty acids (e.g., dodecanoic acid, stearic acid, oleic acid, palmitic acid, etc.) or phosphate esters of long-chain alcohols. Suitable cationic surfactants may include, for example, quaternary ammonium salts.

[0044] Other ink adhesion aids may optionally be present in the primer compositions disclosed herein. Exemplary ink adhesion aids may include, for example, polyvinyl alcohol, styrene-butadiene rubber (SBR), polyethyleneimine, polyurethane, polyvinylpyrrolidone, carboxymethyl cellulose, guar gum, natural gums, cellulose ethers, urea, stearates, hydrogenated hydrocarbon rosin or rosin esters, acrylic polymer dispersions, and any combination thereof.

[0045] Wax may optionally be included in the primer composition to prevent caking by reducing tack. Wax is a hydrophobic organic substance found in petroleum and other oily materials, and is either biosynthesized from plants and animals or obtained through synthesis. Wax is typically a malleable solid at room temperature and may contain one or more higher alkanes (alkanes), particularly ortho- or branched C4 hydrocarbons. 16 -C 100 Alkanes or C 20 -C 50 Alkanes, lipids, and / or oils. When present, the wax can be dispersed as multiple solid wax particles in an aqueous fluid. Once a primer coating is formed from the primer composition, the wax can remain as solid wax particles or a continuous wax layer.

[0046] Suitable waxes used herein may include, but are not limited to, alkane waxes (including Fischer-Tropsch waxes), oxidized alkane waxes, polyolefin waxes, oxidized polyolefin waxes, natural waxes, oxidized natural waxes, and any combination thereof. As used herein, a wax is considered "oxidized" if an oxidized functional group, such as an alcohol, carboxylic acid, epoxide, etc., is introduced into another unsubstituted (alkane) hydrocarbon backbone. The amount of oxidized functional group introduced into a particular oxidized wax may be, for example, sufficient to reduce the hydrophobicity of the wax to a level necessary to promote the formation of an emulsion form of the wax.

[0047] Specific examples of suitable alkane waxes and lipid waxes disclosed herein may include, but are not limited to, pine wax, beeswax, hydrogenated lipids, refined waxes, semi-refined waxes, flake waxes, microcrystalline waxes, beeswax, plant-based waxes such as soybean wax and palm wax, carnauba wax, rice bran wax, lignite wax, sugarcane wax, sunflower wax, shellac wax, hydrogenated castor oil, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), synthetic waxes such as oligomer waxes derived from linear α-olefins or copolymers thereof, Fischer-Tropsch waxes, polyolefin waxes (e.g., polyethylene wax or polypropylene wax), and any combination thereof. Suitable waxes may be provided in the form of wax emulsions in an aqueous fluid. Examples of wax emulsions that may be used in the present invention include, but are not limited to, MICHEM® emulsions such as ME 62330, ME93335, ME 61335, ME 52137, and ME 24414 (Michelman).

[0048] Other optional components present in the primer compositions disclosed herein include, for example, pigments, dyes, optical brighteners, crosslinking agents, defoamers, antistatic agents, dispersants, thickeners, fillers, rheology modifiers, preservatives, silica, and any combination thereof. Suitable examples of the foregoing will be well known to those skilled in the art. When included, additional components or combinations thereof may be selected to modify the properties of the primer composition and / or the properties or appearance of the primer coating formed therefrom. For example, silica may be included to provide a matte appearance to the primer coating. If desired, silica may also be added to reduce tack and prevent sticking during storage.

[0049] This document also provides a base substrate coated with a primer coating formed from the primer compositions of this disclosure. Such a coated substrate may comprise a base substrate and a primer coating disposed on the surface of the base substrate. The primer coating comprises about 50% to about 90% by weight of a coating material based on total solids, the coating material comprising rosin acid and an acid-functionalized vinyl copolymer, the acid-functionalized vinyl copolymer and the rosin acid being at least partially neutralized with a base containing at least one amine; and about 10% to about 50% by weight of a coating enhancer comprising polyurethane based on total solids. The primer coating may comprise the acid-functionalized vinyl copolymer, rosin acid, and polyurethane in the aforementioned weight percentage range. The amount of neutralization of the acid-functionalized vinyl copolymer and rosin acid may be equal to or less than the amount of neutralization present in the corresponding primer composition. When the primer coating is formed, the evaporation of the at least one amine or a portion thereof may result in a lower degree of neutralization in the primer coating. This lower degree of neutralization may provide a stronger bond to the surface of the base substrate because the protonated carboxylic acid can form hydrogen bonds with the surface of the base substrate. Other components that may be present in the primer coating include those mentioned above.

[0050] The coating substrate disclosed herein may further comprise ink, such as HP INDIGO® liquid electrophotographic ink, which is deposited on a primer coating, for example, in the form of a liquid electrophotographic image. Electrophotographic images that can be formed on the primer coating include, but are not limited to, text, illustrations, etc.

[0051] Suitable substrates on which the formed primer coating may be applied are not considered particularly limited. Exemplary substrates that can be suitably coated include, for example, polymer substrates, biopolymer substrates, nonwoven substrates, paper substrates, metal substrates, etc. Specific examples of suitable substrates may include, but are not limited to, paper (e.g., art paper, coated paper, cardboard, printing paper, etc.), films (including polymer films), nonwoven materials, etc. As used herein, the term "film" refers to a substrate made of organic polymer materials such as viscose, acetate, polyethylene, polypropylene, biaxially oriented polypropylene (BOPP), poly(vinyl chloride), polystyrene, polyamide, polycarbonate, or polyester such as polyethylene terephthalate or polybutylene terephthalate. As used herein, the term "nonwoven" refers to a substrate made of fibrous materials such as wood cellulose, cotton, rayon, polyethylene terephthalate, polybutylene terephthalate, polyacrylonitrile, polypropylene, etc., wherein individual fibers have been at least partially fused together.

[0052] As those skilled in the art will understand, BOPP and other polyolefin substrates are low surface energy materials, making them difficult to wet. Such substrates are typically subjected to corona treatment to introduce functional groups suitable for promoting primer coating adhesion. Therefore, any substrate suitable for corona exposure may be subjected to additional corona treatment prior to the formation of a primer coating thereon, as disclosed herein. Suitable corona treatment conditions will be well known to those skilled in the art. Flame treatment may also be applied to some substrates.

[0053] To form a primer coating on a suitable substrate surface, the primer composition of this disclosure can be deposited on the substrate, and the aqueous fluid can be removed to leave the non-volatile components of the primer composition (e.g., at least the acid-functionalized ethylene copolymer, rosin acid, and polyurethane) as the primer coating. There are no particular limitations on the deposition method of the primer composition. When forming the primer coating, at least a portion of at least one amine can also be removed, potentially reducing the degree of neutralization (unless an excess of alkali is present). Once deposited on the substrate, at least partial removal of the alkali (e.g., by evaporation or by forced removal conditions) can increase the interaction strength between the primer coating and the substrate, since the interaction between carboxylic acids and the substrate can be stronger than that of the corresponding carboxylates. The amount of non-volatile components in the primer composition and the amount of primer composition deposited on the substrate determine the thickness of the resulting primer coating. The removal of the aqueous fluid can comprise evaporation of the aqueous fluid, which can occur at room temperature and atmospheric pressure or under accelerated conditions by applying elevated temperature, depressurization, flowing gas, or any combination thereof. If the initially deposited primer coating does not have a suitable weight or thickness, the primer composition can be applied an additional number of times, and then the aqueous fluid can be removed to increase the thickness of the primer coating.

[0054] Therefore, the method of this disclosure may include: applying the primer composition of this disclosure to the surface of a base substrate, and removing an aqueous fluid from the surface of the base substrate to form a coated substrate having a primer coating thereon. Once the coated substrate has been produced, liquid electrophotographic printing can be performed by applying liquid electrophotographic ink to the coated substrate. Exemplary liquid electrophotographic inks may include, for example, HP INDIGO® ink.

[0055] The deposition of the primer composition on the surface of the base substrate can be achieved using any of a variety of methods, such as dipping, spraying, bar coating or roller coating, or using equipment such as a sizing press, water tank, doctor blade coater, cast iron coater, bar coater, air knife coater, curtain coater, film press coater, flexographic coater, etc.

[0056] The primer composition can be applied to the surface of a base substrate in conjunction with a liquid electrophotographic printing process (e.g., the primer composition can be deposited online using a liquid electrophotographic printing apparatus, followed by the deposition of liquid electrophotographic inks). Alternatively, the primer composition can be deposited separately from the liquid electrophotographic printing process, wherein the coated substrate is stored and then fed into the liquid electrophotographic printing apparatus.

[0057] When deposited on the surface of a base substrate, the coating weight of the primer coating can be approximately 0.05 g / m². 2 - Approximately 0.7g / m 2 or approximately 0.1 g / m 2 - Approximately 0.6g / m 2 or approximately 0.1 g / m 2 - Approximately 0.2g / m 2 or approximately 0.2g / m 2 - Approximately 0.3g / m 2 or approximately 0.3g / m 2 - Approximately 0.4g / m 2 or approximately 0.4 g / m 2 - Approximately 0.5g / m 2 or approximately 0.5g / m 2 - Approximately 0.6g / m 2 or approximately 0.6 g / m 2 - Approximately 0.7g / m 2 The coating thickness can be approximately 0.1 micrometers to approximately 5 micrometers, or approximately 0.3 micrometers to approximately 3 micrometers, or approximately 0.5 micrometers to approximately 2 micrometers, or approximately 0.3 micrometers to approximately 0.5 micrometers.

[0058] This document also considers methods for forming the primer compositions of this disclosure. A suitable method for forming the primer composition may include: providing a first dispersion comprising rosin acid and an acid-functionalized ethylene copolymer with an acid value of about 110 mg KOH / g or less in an aqueous fluid; wherein the rosin acid and the acid-functionalized ethylene copolymer are at least partially neutralized with a base comprising at least one amine; and combining a second dispersion comprising polyurethane with the first dispersion to form the primer composition; wherein the primer composition comprises about 50% to about 90% by weight of a combined amount of rosin acid and the acid-functionalized ethylene copolymer, and about 10% to about 50% by weight of polyurethane, each based on the total dissolved or dispersed solids in the primer composition. Optionally, the base may be contacted with the first dispersion under the application of heat, pressure, or any combination thereof. Suitable bases are as described above.

[0059] The implementation plan disclosed in this article includes:

[0060] A. Primer composition. The primer composition comprises: an aqueous fluid; about 50% to about 90% by weight of a coating material based on total dissolved or dispersed solids, said coating material comprising rosin acid and an acid-functionalized vinyl copolymer with an acid value of about 110 mg KOH / g or lower, said acid-functionalized vinyl copolymer and rosin acid being at least partially neutralized with a base comprising at least one amine; and about 10% to about 50% by weight of a coating enhancer comprising polyurethane based on total dissolved or dispersed solids.

[0061] B. Coated substrate. The coated substrate comprises: a base substrate; and a primer coating disposed on the surface of the base substrate; wherein the primer coating comprises: about 60% to about 90% by weight of a coating material based on total solids, the coating material comprising rosin acid and an acid-functionalized ethylene copolymer with an acid value of about 110 mg KOH / g or lower, the acid-functionalized ethylene copolymer and the rosin acid being at least partially neutralized with a base comprising at least one amine; and about 10% to about 50% by weight of a coating enhancer comprising polyurethane based on total solids.

[0062] C. A method for coating a substrate. The method includes: applying a primer composition of A to the surface of a base substrate; removing the aqueous fluid from the surface of the base substrate to form a coated substrate; and applying a liquid electrophotographic ink to the coated substrate.

[0063] D. A method of manufacturing a primer composition. The method comprises: providing a first dispersion comprising rosin acid and an acid-functionalized ethylene copolymer with an acid value of about 110 mg KOH / g polymer or less in an aqueous fluid; wherein the rosin acid and the acid-functionalized ethylene copolymer are at least partially neutralized with a base comprising at least one amine; and combining a second dispersion comprising polyurethane with the first dispersion to form a primer composition; wherein the primer composition comprises about 50% to about 90% by weight of a combined amount of rosin acid and the acid-functionalized ethylene copolymer, and about 10% to about 50% by weight of polyurethane, each based on the total dissolved or dispersed solids in the primer composition.

[0064] Each implementation AD may have one or more of the following additional elements in any combination:

[0065] Element 1: The base therein comprises a mixture of ammonia and at least one amine.

[0066] Element 2: wherein the acid-functionalized ethylene copolymer and rosin acid are completely neutralized with alkali.

[0067] Element 3: wherein the coating material comprises about 70% to about 80% by weight of an acid-functionalized ethylene copolymer and about 20% to about 30% by weight of rosin acid, each based on the combined amount of the acid-functionalized ethylene copolymer and rosin acid in the primer composition.

[0068] Element 4: The acid-functionalized ethylene copolymer comprises an ethylene-(meth)acrylic acid copolymer.

[0069] Element 5: wherein the ethylene-(meth)acrylic acid copolymer comprises about 9% to about 15% by weight of (meth)acrylic acid monomer units, based on the total mass of the ethylene-(meth)acrylic acid copolymer.

[0070] Element 6: The melt flow index (MFI) of the ethylene-(meth)acrylic acid copolymer, as determined by ASTM D1238 at 2.16 kg and 190°C, is about 5 to about 500 g / 10 min.

[0071] Element 7: The acid value of the ethylene-(meth)acrylic acid copolymer is about 100 mg KOH / g or lower.

[0072] Element 8: Wherein, when combined in an aqueous fluid, the coating material and the coating enhancer together define an aqueous emulsion.

[0073] Element 9: wherein at least the polyurethane is emulsified in the aqueous fluid.

[0074] Element 10: wherein the coating material is dissolved in the aqueous fluid and the polyurethane is emulsified in the aqueous fluid.

[0075] Element 11: The base substrate comprises a polymer substrate or a paper substrate.

[0076] Element 12: The coating weight of the primer coating is approximately 0.05 g / m³. 2 - Approximately 1.5 g / m 2 .

[0077] Element 13: The coated substrate further comprises liquid electrophotographic ink deposited on a primer coating.

[0078] Element 14: wherein the alkali is contacted with the acid-functionalized ethylene copolymer and rosin acid under pressure.

[0079] Element 15: wherein the first dispersion comprises about 70% to about 80% by weight of an acid-functionalized ethylene copolymer and about 20% to about 30% by weight of rosin acid, each based on the combined amount of the acid-functionalized ethylene copolymer and rosin acid in the first dispersion.

[0080] By way of non-limiting examples, exemplary combinations applicable to A include, but are not limited to, 1 or 1 and 2, and 3 or 15; 1 or 1 and 2, and 4; 1 or 1 and 2, and 4 and 5; 1 or 1 and 2, and 6; 1 or 1 and 2, and 4 and 6; 1 or 1 and 2, and 7; 1 or 1 and 2, and 8; 1 or 1 and 2, and 9; 1 or 1 and 2, and 10; 1 or 1 and 2, and 11; 1 or 1 and 2, and 12; 3 or 15, and 4; 3 or 15, and 5; 3 or 15, and 4 and 5; 3 or 15, and 6; 3 or 15, And 4 and 6; 3 or 15, and 7; 3 or 15, and 8; 3 or 15, and 9; 3 or 15, and 10; 3 or 15, and 11; 3 or 15, and 12; 4 and optional 5, 6, and / or 7, and 8; 4 and optional 5, 6, and / or 7, and 9; 4 and optional 5, 6, and / or 7, and 10; 4 and optional 5, 6, and / or 7, and 11; 4 and optional 5, 6, and / or 7, and 12; 8, 9, and / or 10, and 11; and 8, 9, and / or 10, and 12.

[0081] Other implementation schemes disclosed in this article include:

[0082] Implementation Scheme 1. A primer composition comprising:

[0083] Aqueous fluids;

[0084] Based on approximately 50% to 90% by weight of the total dissolved or dispersed solids, the coating material comprises rosin acid and an acid-functionalized ethylene copolymer with an acid value of approximately 110 mg KOH / g or lower, wherein the acid-functionalized ethylene copolymer and the rosin acid are at least partially neutralized with a base containing at least one amine; and

[0085] Based on approximately 10% to 50% by weight of polyurethane-containing coating enhancers, on a total dissolved or dispersed solids basis.

[0086] Implementation Scheme 2. The primer composition of Implementation Scheme 1, wherein the alkali comprises a mixture of ammonia and the at least one amine.

[0087] Implementation Scheme 3. The primer composition of Implementation Scheme 1, wherein the acid-functionalized ethylene copolymer and rosin acid are completely neutralized with alkali.

[0088] Implementation Scheme 4. The primer composition of Implementation Scheme 1, wherein the coating material comprises about 70% to about 80% by weight of an acid-functionalized ethylene copolymer and about 20% to about 30% by weight of rosin acid, or about 50% to about 70% by weight of an acid-functionalized ethylene copolymer and about 30% to about 50% by weight of rosin acid, each based on the combined amount of acid-functionalized ethylene copolymer and rosin acid in the primer composition.

[0089] Implementation Scheme 5. The primer composition of Implementation Scheme 1, wherein the acid-functionalized ethylene copolymer comprises an ethylene-(meth)acrylic acid copolymer.

[0090] Implementation Scheme 6. The primer composition of Implementation Scheme 5, wherein the ethylene-(meth)acrylic acid copolymer comprises about 9% to about 15% by weight of (meth)acrylic acid monomer units, based on the total mass of the ethylene-(meth)acrylic acid copolymer.

[0091] Implementation Scheme 7. The primer composition of Implementation Scheme 5, wherein the ethylene-(meth)acrylic acid copolymer has a melt flow index (MFI) of about 5 to about 500 g / 10 min as determined by ASTM D1238 at 2.16 kg and 190 °C.

[0092] Implementation Scheme 8. The primer composition of Implementation Scheme 5, wherein the acid value of the ethylene-(meth)acrylic acid copolymer is about 100 mg KOH / g or less.

[0093] Implementation Scheme 9. A primer composition of any one of Implementation Schemes 1-8, wherein when combined in the aqueous fluid, the coating material and the coating enhancer together define an aqueous emulsion.

[0094] Implementation Scheme 10. The primer composition of Implementation Scheme 9, wherein at least the polyurethane is emulsified in the aqueous fluid.

[0095] Implementation Scheme 11. The primer composition of Implementation Scheme 10, wherein the coating material is dissolved in the aqueous fluid and the polyurethane is emulsified in the aqueous fluid.

[0096] Implementation Scheme 12. A coated substrate, comprising:

[0097] Basic substrate; and

[0098] A primer coating is applied to the surface of the base substrate;

[0099] The primer coating comprises: approximately 60% to approximately 90% by weight of a coating material based on total solids, the coating material comprising rosin acid and an acid-functionalized ethylene copolymer with an acid value of approximately 110 mg KOH / g or lower, the acid-functionalized ethylene copolymer and the rosin acid being at least partially neutralized with a base containing at least one amine; and

[0100] Based on a total solids content of approximately 10% to 50% by weight of a polyurethane-containing coating enhancer.

[0101] Implementation Scheme 13. The coating substrate of Implementation Scheme 12, wherein the base substrate comprises a polymer substrate or a paper substrate.

[0102] Implementation Scheme 14. The substrate coated according to Implementation Scheme 12, wherein the coating weight of the primer coating is approximately 0.05 g / m². 2 - Approximately 1.5 g / m 2 .

[0103] Implementation Scheme 15. The coated substrate of Implementation Scheme 12, further comprising:

[0104] Liquid electrophotographic ink deposited on the primer coating.

[0105] Implementation Scheme 16. A substrate coated according to any one of Implementation Schemes 12-15, wherein the coating material comprises about 70% to about 80% by weight of an acid-functionalized ethylene copolymer and about 20% to about 30% by weight of rosin acid, or about 50% to about 70% by weight of an acid-functionalized ethylene copolymer and about 30% to about 50% by weight of rosin acid, each based on the combined amount of acid-functionalized ethylene copolymer and rosin acid in the primer coating.

[0106] Implementation Scheme 17. A substrate coated according to any one of Implementation Schemes 12-15, wherein the acid-functionalized ethylene copolymer comprises an ethylene-(meth)acrylic acid copolymer.

[0107] Implementation Scheme 18. The coated substrate of Implementation Scheme 17, wherein the ethylene-(meth)acrylic acid copolymer comprises about 9% to about 15% by weight of (meth)acrylic acid monomer units, based on the total mass of the (meth)acrylic acid polymer.

[0108] Implementation Scheme 19. The coated substrate of Implementation Scheme 17, wherein the ethylene-(meth)acrylic acid copolymer has a melt flow index (MFI) of about 5 to about 500 g / 10 min as determined by ASTM D1238 at 2.16 kg and 190 °C.

[0109] Implementation Scheme 20. The coated substrate of Implementation Scheme 17, wherein the acid value of the ethylene-(meth)acrylic acid copolymer is about 100 mg KOH / g or lower.

[0110] Implementation plan 21. Method, which includes:

[0111] Apply the primer composition of any one of embodiments 1-8 to the surface of the base substrate;

[0112] The coated substrate is formed by removing the aqueous fluid from the surface of the base substrate; and

[0113] Liquid electrophotographic ink is applied to the coated substrate.

[0114] Implementation Scheme 22. Method, which includes:

[0115] A first dispersion is provided, comprising rosin acid and an acid-functionalized ethylene copolymer with an acid value of about 110 mg KOH / g or lower in an aqueous fluid;

[0116] The rosin acid and acid-functionalized ethylene copolymer is at least partially neutralized with a base containing at least one amine; and

[0117] A second dispersion containing polyurethane is combined with the first dispersion to form a primer composition;

[0118] The primer composition comprises about 50% to about 90% by weight of the combined amount of the rosin acid and acid-functionalized ethylene copolymer, and about 10% to about 50% by weight of the polyurethane, each based on the total dissolved or dispersed solids in the primer composition.

[0119] Implementation Scheme 23. The method of Implementation Scheme 22, wherein the base comprises a mixture of ammonia and the at least one amine.

[0120] Implementation Scheme 24. The method of Implementation Scheme 22, wherein the acid-functionalized ethylene copolymer and rosin acid are completely neutralized with a base.

[0121] Implementation Scheme 25. The method of Implementation Scheme 22, wherein the alkali is contacted with the acid-functionalized ethylene copolymer and rosin acid under pressure.

[0122] Implementation Scheme 26. The method of Implementation Scheme 22, wherein the first dispersion comprises about 70% to about 80% by weight of an acid-functionalized ethylene copolymer and about 20% to about 30% by weight of rosin acid, or about 50% to about 70% by weight of an acid-functionalized ethylene copolymer and about 30% to about 50% by weight of rosin acid, each based on the combined amount of the acid-functionalized ethylene copolymer and rosin acid in the first dispersion.

[0123] Implementation Scheme 27. The method of Implementation Scheme 22, wherein the acid-functionalized ethylene copolymer comprises an ethylene-(meth)acrylic acid copolymer.

[0124] Implementation Scheme 28. The method of Implementation Scheme 27, wherein the ethylene-(meth)acrylic acid copolymer comprises about 9% to about 15% by weight of (meth)acrylic acid monomer units, based on the total mass of the ethylene-(meth)acrylic acid copolymer.

[0125] Implementation Scheme 29. The method of Implementation Scheme 27, wherein the melt flow index (MFI) of the ethylene-(meth)acrylic acid copolymer, as determined by ASTM D1238 at 2.16 kg and 190 °C, is about 5 to about 500 g / 10 min.

[0126] Implementation Scheme 30. The method of Implementation Scheme 27, wherein the acid value of the ethylene-(meth)acrylic acid copolymer is about 100 mg KOH / g or lower.

[0127] Implementation Scheme 31. The method of any one of Implementation Schemes 22-30, wherein at least the polyurethane is emulsified in an aqueous fluid.

[0128] Implementation Scheme 32. The method of Implementation Scheme 31, wherein the acid-functionalized ethylene copolymer, rosin acid and polyurethane together define an aqueous emulsion.

[0129] To facilitate a better understanding of this disclosure, examples of different representative embodiments are provided below. These examples should not in any way be construed as limiting or restricting the scope of this disclosure.

[0130] Example

[0131] Dispersion formation

[0132] Example 1: Ethylene-Methacrylic Acid / Rosin Acid Dispersion 1. The copolymer / rosin acid co-dispersion was prepared as follows: 140 g of NUCREL 699 ethylene-methacrylic acid copolymer (Dow, 11% wt% methacrylic acid; MFI = 95 g / 10 min, determined by ASTM D1238 at 2.16 kg and 190 °C), 60 g of FORAL AX-E hydrogenated rosin acid (Eastman, acid value = 158-173 mg KOH / g resin, determined by ASTM D-465), and 800 g of water were mixed with sufficient dimethylethanolamine to completely neutralize the copolymer and rosin acid. The mixture was heated under pressure at 130 °C for 2 hours and then cooled to room temperature. The resulting dispersion was free of grit and undispersed material and had a translucent appearance.

[0133] Example 2: Ethylene-Methacrylamide / Rosin Acid Dispersion 2. Example 1 was repeated, except that NUCREL 599 ethylene-methacrylic acid copolymer (Dow, 10% by weight methacrylic acid; MFI = 450 g / 10 min, determined by ASTM D1238 at 2.16 kg and 190 °C) was used instead of NUCREL 699. The resulting dispersion was free of grit and undispersed material and had a translucent appearance.

[0134] Example 3: Ethylene-Methacrylamide / Rosin Acid Dispersion 3. Example 1 was repeated, except that NUCREL 960 ethylene-methacrylic acid copolymer (Dow, 15% by weight methacrylic acid; MFI = 60 g / 10 min, determined by ASTM D1238 at 2.16 kg and 190 °C) was used instead of NUCREL 699. The resulting dispersion was free of grit and undispersed material and had a translucent appearance.

[0135] Example 4: Ethylene-Methacrylamide / Rosin Acid / Polyurethane Dispersion 1. The dispersion of Example 1 was blended with a dispersion of NEOREZ® R 605 aliphatic polyurethane in water (Covestro) to form a combined dispersion. This combined ethylene-methacrylic acid / rosin acid / polyurethane dispersion contains 30 wt% polyurethane solids and 70 wt% combined ethylene-acrylic acid and rosin acid solids (individually, 49 wt% ethylene-acrylic acid and 21 wt% rosin acid), each measured based on total dispersed solids.

[0136] Example 5: Ethylene-Methacrylamide / Rosin Acid / Polyurethane Dispersion 2. The dispersion of Example 2 was blended with a dispersion of NEOREZ® R 605 aliphatic polyurethane in water (Covestro) to form a combined dispersion. This combined ethylene-methacrylic acid / rosin acid / polyurethane dispersion contains 20 wt% polyurethane solids and 80 wt% combined ethylene-acrylic acid and rosin acid solids (individually, 56 wt% ethylene-acrylic acid and 24 wt% rosin acid), each measured based on total dispersed solids.

[0137] Example 6: Ethylene-Methacrylamide / Rosin Acid / Polyurethane Dispersion 3. The dispersion of Example 3 was blended with a dispersion of NEOREZ® R 605 aliphatic polyurethane in water (Covestro) to form a combined dispersion. This combined ethylene-methacrylic acid / rosin acid / polyurethane dispersion contains 20% by weight of polyurethane solids and 80% by weight of combined ethylene-acrylic acid and rosin acid solids (individually, 56% by weight of ethylene-acrylic acid and 24% by weight of rosin acid), each measured based on total dispersed solids.

[0138] Coating and Adhesion Testing

[0139] Batch coating procedure. The selected dispersion prepared as described above is coated onto a corona-treated biaxially oriented PET or PP film. Corona treatment is performed at 200-2000 W, with 2000 W typically exhibiting optimal adhesion. The primer composition is applied to an 8" × 14" sheet of corona-treated film using a 0.5 Mayer standard coating stick via manual or automatic coating machine and dried in a forced-air oven at 105°C for 60 seconds. The film is then removed from the oven and equilibrated at room temperature for 1 hour. Once equilibrated, the film is immediately tested or applied at regular intervals to a roll of pre-primed biaxially oriented PET substrate using double-sided 610 3M tape. The tape-bonded substrate is then printed under standard HP INDIGO® liquid electrophotographic printing conditions.

[0140] Online coating process. The selected dispersion prepared above is coated onto a corona-treated base substrate film (polyethylene terephthalate-PET, biaxially oriented polypropylene-BOPP, or polyethylene-PE) using a flexographic or roller coating unit, inline with liquid electrophotographic printing equipment. The corona treatment is also performed online before the coating unit, with a corona power intensity of 500-2000 W. The coating weight is 0.24 g / m³. 2 Immediately after applying and drying the primer coating, the coated substrate was printed with HP INDIGO® liquid electrophotographic ink under standard printing conditions. Further adhesion tests were performed on the samples prepared as shown in Table 1 below (see Table 2).

[0141] Table 1

[0142]

[0143] Adhesion Test. The adhesion of the primer coating to the substrate and the ink to the primer coating was evaluated by applying SCOTCH® 810 (3M) tape to the primer coating or printed ink and removing the tape after 15 minutes. This test procedure is similar to that described in ASTM 2252 / 2252M, except that SCOTCH® 810 tape is used instead of SCOTCH® 610 tape, and the tape is pressed onto the coated substrate using a 2kg roller with four passes. The percentage of the printed image or primer coating removed was visually evaluated. To assess the removal of the primer coating, an indicator dye sensitive to the primer coating was used to help visualize the locations where the primer coating was removed. Adhesion tests were performed in a similar manner, omitting the electrophotographic ink. The adhesion test results are summarized in Table 2.

[0144] Table 2

[0145]

[0146] As shown in Table 2, the ethylene-acrylic acid / rosin acid dispersion provides a primer coating that initially adheres readily to the substrate, but becomes significantly less stable once liquid electrophotographic ink is printed onto it. It is believed that in the absence of the polyurethane, the primer coating components preferentially adhere to the liquid electrophotographic ink, resulting in the primer coating being removed from the surface of the base substrate when the liquid electrophotographic ink is present. In contrast, when the polyurethane is also present in the primer coating, the primer coating adheres firmly to the base substrate and also promotes good ink adhesion.

[0147] All the literature described herein is incorporated herein for the purposes of all jurisdictions that allow such practice, including any priority literature and / or test procedures to the extent not contradicting this document. It will be apparent from the foregoing general description and specific embodiments that, while the form of this disclosure has been described and illustrated, various modifications may be made without departing from the spirit and scope of this disclosure. Therefore, it is not intended to limit this disclosure. For example, a composition described herein may not contain any component or composition not expressly described or disclosed herein. Any method may not include any steps not described or disclosed herein. Similarly, the term “comprising” is considered synonymous with the term “including.” Whenever a method, composition, element, or group of elements precedes the transitional phrase “comprising,” it should be understood that the same composition or group of elements having the transitional phrase “essentially constitutes,” “consisting of,” “selected from,” or “is” preceding the description of the composition, one or more elements is also considered, and vice versa.

[0148] Unless otherwise stated, all figures used in this specification and related claims to indicate the amount or properties of components, such as molecular weight, reaction conditions, etc., should be understood to be modified by the term "about" in all cases. Therefore, unless otherwise indicated, the numerical parameters set forth in the following specification and appended claims are approximate values ​​that may vary depending on the desired properties sought to be obtained according to embodiments of the invention. At the very least, and without attempting to limit the application of the principle of equivalence with the scope of the claims, each numerical parameter should be interpreted at least according to the number of significant figures reported and by applying general rounding techniques.

[0149] Whenever a numerical range with a lower and upper limit is disclosed, any number falling within that range and any range included therein is specifically disclosed. Specifically, each range of values ​​disclosed herein (in the form of “about a to about b,” or equivalently, “about a to b,” or equivalently, “about ab”) should be understood to describe each numerical value and range contained within a wider range of values. Similarly, unless otherwise explicitly and clearly defined by the patentee, the terms in the claims have their ordinary, common meaning. Furthermore, the indefinite articles “an” or “a” used in the claims are defined herein as indicating one or more elements introduced therein.

[0150] This document presents one or more exemplary embodiments. For clarity, not all features of the physical implementation are described or illustrated in this application. It should be understood that the development of the physical implementations of this disclosure involves numerous implementation-specific decisions to achieve the developer's objectives, such as compliance with system-related, business-related, governmental-related, and other restrictions that vary with implementation and time. While the developer's efforts may be time-consuming, these efforts will be routine tasks for those skilled in the art and those who benefit from this disclosure.

[0151] Therefore, this disclosure is well suited to achieving the stated purposes and advantages, and those inherent therein. The specific embodiments disclosed above are merely exemplary, as it will be apparent to those skilled in the art, who benefit from the teachings herein, that modifications and practices can be made to this disclosure in different but equivalent ways. Furthermore, the details of the constructions or designs shown herein are not intended to limit the scope of the disclosure, except as described in the following claims. It is therefore apparent that the specific exemplary embodiments disclosed above can be changed, combined, or modified, and all such changes are considered to be within the scope and spirit of this disclosure. The embodiments disclosed herein by way of example may be suitably practiced in the absence of any elements not specifically disclosed herein and / or any optional elements disclosed herein.

Claims

1. A primer composition comprising: Aqueous fluids; Based on approximately 50% to 90% by weight of the total dissolved or dispersed solids, the coating material comprises rosin acid and an acid-functionalized ethylene copolymer with an acid value of approximately 110 mg KOH / g or lower, wherein the acid-functionalized ethylene copolymer and the rosin acid are at least partially neutralized with a base containing at least one amine; and Based on approximately 10% to 50% by weight of polyurethane-containing coating enhancers, on a total dissolved or dispersed solids basis.

2. The primer composition of claim 1, wherein the alkali comprises a mixture of ammonia and the at least one amine.

3. The primer composition of claim 1, wherein the acid-functionalized ethylene copolymer and the rosin acid are completely neutralized with the base.

4. The primer composition of claim 1, wherein the coating material comprises about 70% to about 80% by weight of the acid-functionalized ethylene copolymer and about 20% to about 30% by weight of the rosin acid, or about 50% to about 70% by weight of the acid-functionalized ethylene copolymer and about 30% to about 50% by weight of the rosin acid, each based on the combined amount of the acid-functionalized ethylene copolymer and the rosin acid in the primer composition.

5. The primer composition of claim 1, wherein the acid-functionalized ethylene copolymer comprises an ethylene-(meth)acrylic acid copolymer.

6. The primer composition of claim 5, wherein the ethylene-(meth)acrylic acid copolymer comprises about 9% to about 15% by weight of (meth)acrylic acid monomer units, based on the total mass of the ethylene-(meth)acrylic acid copolymer.

7. The primer composition of claim 5, wherein the ethylene-(meth)acrylic acid copolymer has a melt flow index (MFI) of about 5 to about 500 g / 10 min as determined by ASTM D1238 at 2.16 kg and 190°C.

8. The primer composition of claim 5, wherein the acid value of the ethylene-(meth)acrylic acid copolymer is about 100 mg KOH / g or lower.

9. The primer composition of any one of claims 1-8, wherein when combined in the aqueous fluid, the coating material and the coating enhancer together define an aqueous emulsion.

10. The primer composition of claim 9, wherein at least the polyurethane is emulsified in the aqueous fluid.

11. The primer composition of claim 10, wherein the coating material is dissolved in the aqueous fluid, and the polyurethane is emulsified in the aqueous fluid.

12. A coated substrate comprising: Basic substrate; and A primer coating is applied to the surface of the base substrate; The primer coating comprises: Based on a total solids content of approximately 60% to 90% by weight of a coating material, said coating material comprising rosin acid and an acid-functionalized ethylene copolymer with an acid value of approximately 110 mg KOH / g or lower, said acid-functionalized ethylene copolymer and said rosin acid being at least partially neutralized with a base comprising at least one amine; and Based on a total solids content of approximately 10% to 50% by weight of a polyurethane-containing coating enhancer.

13. The coated substrate of claim 12, wherein the base substrate comprises a polymer substrate or a paper substrate.

14. The coated substrate of claim 12, wherein the primer coating has a coating weight of about 0.05 g / m³. 2 - Approximately 1.5 g / m 2 .

15. The coated substrate of claim 12, further comprising: Liquid electrophotographic ink deposited on the primer coating.

16. The coated substrate of any one of claims 12-15, wherein the coating material comprises about 70% to about 80% by weight of the acid-functionalized ethylene copolymer and about 20% to about 30% by weight of the rosin acid, or about 50% to about 70% by weight of the acid-functionalized ethylene copolymer and about 30% to about 50% by weight of the rosin acid, each based on the combined amount of the acid-functionalized ethylene copolymer and the rosin acid in the primer coating.

17. The coated substrate of any one of claims 12-15, wherein the acid-functionalized ethylene copolymer comprises an ethylene-(meth)acrylic acid copolymer.

18. The coated substrate of claim 17, wherein the ethylene-(meth)acrylic acid copolymer comprises about 9% to about 15% by weight of (meth)acrylic acid monomer units, based on the total mass of the (meth)acrylic acid polymer.

19. The coated substrate of claim 17, wherein the melt flow index (MFI) of the ethylene-(meth)acrylic acid copolymer, as determined by ASTM D1238 at 2.16 kg and 190°C, is about 5 to about 500 g / 10 min.

20. The coated substrate of claim 17, wherein the acid value of the ethylene-(meth)acrylic acid copolymer is about 100 mg KOH / g or lower.

21. A method, comprising: Apply the primer composition according to any one of claims 1-8 to the surface of a base substrate; The coated substrate is formed by removing the aqueous fluid from the surface of the base substrate; and Liquid electrophotographic ink is applied to the coated substrate.

22. A method, comprising: A first dispersion is provided, comprising rosin acid and an acid-functionalized ethylene copolymer with an acid value of about 110 mg KOH / g or lower in an aqueous fluid; The rosin acid and the acid-functionalized ethylene copolymer are at least partially neutralized with a base containing at least one amine; and A second dispersion containing polyurethane is combined with the first dispersion to form a primer composition; The primer composition comprises about 50% to about 90% by weight of the rosin acid and the acid-functionalized ethylene copolymer, and about 10% to about 50% by weight of the polyurethane, each based on the total dissolved or dispersed solids in the primer composition.

23. The method of claim 22, wherein the base comprises a mixture of ammonia and the at least one amine.

24. The method of claim 22, wherein the acid-functionalized ethylene copolymer and the rosin acid are completely neutralized with the base.

25. The method of claim 22, wherein the base is contacted with the acid-functionalized ethylene copolymer and the rosin acid under pressure.

26. The method of claim 22, wherein the first dispersion comprises about 70% to about 80% by weight of the acid-functionalized ethylene copolymer and about 20% to about 30% by weight of the rosin acid, or about 50% to about 70% by weight of the acid-functionalized ethylene copolymer and about 30% to about 50% by weight of the rosin acid, each based on the combined amount of the acid-functionalized ethylene copolymer and the rosin acid in the first dispersion.

27. The method of claim 22, wherein the acid-functionalized ethylene copolymer comprises an ethylene-(meth)acrylic acid copolymer.

28. The method of claim 27, wherein the ethylene-(meth)acrylic acid copolymer comprises about 9% to about 15% by weight of (meth)acrylic acid monomer units, based on the total mass of the ethylene-(meth)acrylic acid copolymer.

29. The method of claim 27, wherein the melt flow index (MFI) of the ethylene-(meth)acrylic acid copolymer, as determined by ASTM D1238 at 2.16 kg and 190°C, is about 5 to about 500 g / 10 min.

30. The method of claim 27, wherein the acid value of the ethylene-(meth)acrylic acid copolymer is about 100 mgKOH / g or lower.

31. The method of any one of claims 22-30, wherein at least the polyurethane is emulsified in the aqueous fluid.

32. The method of claim 31, wherein the acid-functionalized ethylene copolymer, the rosin acid, and the polyurethane together define an aqueous emulsion.

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