Aqueous composition and opaque coating provided thereby

Abstract

An aqueous composition can be used to pre-treat a substrate (300) prior to inkjet printing in order to provide a white opaque background (330) for an inkjet printed image. The aqueous composition includes: 5 to 30 weight percent, based on the total weight of the aqueous composition, of (a) one or more water-soluble salts of polyvalent metal cations; 5 to 30 weight percent of (b) a non-ionic or cationic water-soluble or water-dispersible polymeric binder material; and an amount of 5 to 60 weight percent of (c) surface-treated visible light-scattering particles having a D 50 The pre-treated substrate can be used as an inkjet receiving medium that can be readily inkjet printed, in particular with anionically stabilized water-based pigment-based inks.

Description

TECHNICAL FIELD

[0001] The present invention relates to the field of inkjet printing. More particularly, it relates to aqueous compositions that can be applied as a pre-treatment to a substrate to form an inkjet receptive medium having an opaque ("white") coating or pattern. The inkjet receptive medium has enhanced inkjet printing and imaging properties and can be printed using aqueous pigment-based inkjet inks or aqueous colorless inkjet inks. BACKGROUND

[0003] It is well known to deposit aqueous inks, particularly those having anionically stabilized dispersed pigment colorants, onto a substrate having cations of polyvalent metal salts on its surface. The presence of such polyvalent metal cations can be used to prevent deposited ink drops from penetrating too far below the surface of an absorbent substrate, thereby preventing a reduction in optical density. The polyvalent metal cations can also be used to prevent adjacent deposited ink drops of the same or different color from bleeding or coalescing on a less absorbent substrate, such as a hydrophobic substrate, thereby preventing the formation of a hazy or grainy appearing image. Surface treatments comprising aqueous salts of polyvalent metal ions are particularly advantageous for high speed printing using page-wide inkjet arrays, whereby adjacent ink drops are deposited onto the substrate within only a few microseconds of each other.

[0004] U.S. Patents 9,067,448 (Dannhauser et al.) and 9,434,201 (Dannhauser et al.) describe inkjet receptive media suitable for high speed inkjet printing, the media comprising a substrate having a topmost layer coated thereon, the topmost layer comprising a water-soluble salt of a polyvalent metal cation and a crosslinked hydrophilic polymeric binder. Various types of various inorganic particles can also be present in the topmost layer.

[0005] U.S. Patent 8,562,126 (Xiang et al.) describes inkjet receptive media comprising a substrate and a topmost layer coated thereon, wherein the topmost layer includes one or more water-soluble salts of a polyvalent metal cation, a cationic polyelectrolyte comprising a amidine moiety, and a second polymer different from the cationic polyelectrolyte comprising a amidine moiety.

[0006] Improvements in inkjet printed image durability can be provided using the teachings of U.S. Patent 9,427,975 (Bugner et al.), in which an inkjet printed image on an inkjet receptive medium is dried immediately after printing, subjected to pure water and heat, and then returned to ambient conditions.

[0007] Inkjet receptive media known in the art for high speed inkjet printing using anionically stabilized aqueous pigment-based inks sometimes have low opacity or are even transparent, and in many cases, the inkjet receptive layers on these media, such as those described in the patents described above, are also visually clear and transparent or translucent. However, when inkjet printing on clear film substrates or dark substrates, it is often desirable to include a "white" opaque layer or pattern underneath the subsequent various color inkjet printed images.

[0008] This goal can be achieved by inkjet printing a white ink layer, such as that described in U.S. Patent 9,994,723 (Bauer et al.), followed by applying a known inkjet receptive layer formulation. While this approach can provide some opacity in the inkjet receptive media, it adds the complexity of requiring a separate ink deposition or coating step to separate the "white" ink layer underneath the inkjet receptive layer. The multiple layers on the substrate then form a requirement of careful optimization of the multi-step operations for applying the multiple layers to ensure good adhesion and avoid adverse interactions between the layer formulations. In addition, the application of a white inkjet ink can not provide the desired opacity to the resulting inkjet receptive media.

[0009] To avoid these problems, efforts have been made to provide a white opaque layer using flexographic or gravure printing of a "white" pigmented composition prior to inkjet printing. However, attempts to directly inkjet print using anionically stabilized aqueous pigment-based inks onto a pre-printed white layer applied by these means resulted in highly variable and unacceptable image quality.

[0010] Certain types of white inkjet receptive layers have been proposed in the art that are formed as microporous layers or contain cationic fixatives. However, these white inkjet receptive layers are relatively thick and are not suitable for high speed inkjet printing on a commercial scale, especially when anionically stabilized aqueous pigment-based inks are desired to be used.

[0011] Therefore, there is a need to provide a white background, in the form of a uniform layer or pattern, as an inkjet receptive layer that is relatively thin and has high opacity, and desirably, to use flexographic or gravure coating or inkjet printing techniques to provide such an inkjet receptive layer at high speed. In particular, there is a need to provide such a white background on which anionically stabilized aqueous pigment-based inks can be inkjet printed at high speed in commercial operations to provide high quality monochrome or multicolor images with excellent adhesion between the white background and the underlying substrate, between the white background and the subsequent inkjet printed images, and between the non-inkjet printed white background and any subsequent layers or coatings that can be applied on top of it downstream in the printing operation. SUMMARY

[0013] To address the problems described above, the present application provides an aqueous composition for pretreating a substrate prior to inkjet printing on the substrate, the aqueous composition having at least 2 percent solids and up to and including 90 percent solids, and the aqueous composition comprising:

[0014] (a) water soluble salts of one or more polyvalent metal cations, the (a) one or more water soluble salts being present in an amount of at least 0.6 weight percent and up to and including 30 weight percent;

[0015] (b) one or more non-ionic or cationic water soluble or water dispersible polymeric binder materials, the (b) one or more non-ionic or cationic water soluble or water dispersible polymeric binder materials being present in an amount of at least 0.1 weight percent and up to and including 30 weight percent; and

[0016] (c) visible light scattering particles that have been surface treated such that the aqueous composition has a stable zeta potential greater than +4 millivolts, and the (c) surface treated visible light scattering particles being present in an amount of at least 5 weight percent and up to and including 60 weight percent,

[0017] wherein the amounts of (a), (b), and (c) components are based on the total weight of the aqueous composition.

[0018] Some particularly useful embodiments of the present application include an aqueous composition for pretreating a substrate prior to inkjet printing on the substrate, the aqueous composition having at least 5 percent solids and up to and including 70 percent solids, and a dynamic viscosity of at least 30 centipoise (30 mPa.s) and up to and including 800 centipoise (800 mPa.s) as measured at 25°C using a Brookfield Spindle Viscometer, and

[0019] the aqueous composition comprising:

[0020] (a) water soluble salts of one or more of magnesium (+2), calcium (+2), barium (+2), or mixtures thereof, the (a) one or more water soluble salts being present in an amount of at least 1 weight percent and up to and including 25 weight percent based on the total weight of the aqueous composition;

[0021] (b) one or more non-ionic or cationic water soluble or water dispersible polymeric binder materials comprising at least polyvinyl alcohol, polyvinyl amine, polyethylene imine, copolymers derived from at least ethylene amine and ethylene alcohol, or combinations of two or more of these polymeric materials, the (b) one or more non-ionic or cationic water soluble or water dispersible polymeric binder materials being present in an amount of at least 0.1 weight percent and up to and including 8 weight percent based on the total weight of the aqueous composition;

[0022] (c) visible light-scattering particles comprising titanium dioxide particles that scatter visible light, which have been surface treated such that the aqueous composition has a stable zeta potential greater than +10 millivolts, wherein the surface treated visible light-scattering titanium dioxide particles exhibit a Dv50, as measured using a particle size analyzer that provides a volume weighted particle size distribution, of at least 0.04 μιη and up to and including 2 μιη 50 and the surface treated visible light-scattering particles are present in an amount of at least 10 weight percent and up to and including 40 weight percent, based on the total weight of the aqueous composition;

[0023] (d) particles different from the (c) component, the (d) particles having a Rockwell hardness less than or equal to R75, and present in an amount of at least 0.05 weight percent and up to and including 3 weight percent, based on the total weight of the aqueous composition;

[0024] (e) a cross-linkable polymeric material different from all of (a), (b), (c), and (d), and present in an amount of at least 0.2 weight percent and up to and including 8 weight percent, based on the total weight of the aqueous composition; and

[0025] (f) a dispersing aid for the (c) surface treated visible light-scattering titanium dioxide particles, the (f) dispersing aid being a polymer having protonated nitrogen atoms, and present in an amount of at least 0.2 weight percent and up to and including 50 weight percent, based on the total weight of the (c) surface treated visible light-scattering titanium dioxide particles.

[0026] Further, the inkjet receiving media comprises a substrate and a topcoat composition disposed on a surface thereof, the topcoat composition comprising:

[0027] (a) one or more water soluble salts of polyvalent metal cations, the (a) one or more water soluble salts being present in an amount of at least 0.4 weight percent and up to and including 40 weight percent;

[0028] (b) one or more non-ionic or cationic water soluble or water dispersible polymeric binder materials, present in an amount of at least 0.5 weight percent and up to and including 90 weight percent; and

[0029] (c) visible light-scattering particles, which have been surface treated, present in an amount of at least 6 weight percent and up to and including 90 weight percent,

[0030] wherein the amounts of the (a), (b), and (c) components are based on the total weight of the topcoat composition.

[0031] In some embodiments of the present application, the substrate comprises a transparent or translucent polymeric film, and the topcoat composition has a thickness of at least 0.2 g / m2 and up to and including 2 g / m 2 of dry solids coating weight, and the finish composition comprises the following (a), (b), (c), (d), (e), and (f) components:

[0032] (a) one or more water-soluble salts of magnesium (+2), calcium (+2), barium (+2), or mixtures thereof, present in an amount of at least 0.4 wt% and up to and including 40 wt%, based on the total weight of the finish composition;

[0033] (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder materials comprising at least polyvinyl alcohol, polyvinyl amine, polyethylene imine, a copolymer derived at least in part from ethylene amine and ethylene alcohol, or a combination of two or more of these polymeric materials, present in an amount of at least 2 wt% and up to and including 90 wt%, based on the total weight of the finish composition;

[0034] (c) surface-treated visible light-scattering particles comprising surface-treated visible light-scattering titanium dioxide particles present in an amount of at least 6 wt% and up to and including 90 wt%, based on the total weight of the finish composition, the surface-treated visible light-scattering titanium dioxide particles exhibiting a D 50 (50%) particle size of at least 0.04 μm and up to and including 2 μm, as measured using a particle size analyzer that provides a volume-weighted particle size distribution;

[0035] (d) particles different from the (c) component, the (d) particles having a Rockwell hardness less than or equal to R75, and present in an amount of at least 0.06 wt% and up to and including 10 wt%, based on the total weight of the finish composition;

[0036] (e) a cross-linkable polymeric material different from all of the (a), (b), (c), and (d) components, present in an amount of at least 0.1 wt% and up to and including 20 wt%, based on the total weight of the finish composition; and

[0037] (f) a dispersing aid for the (c) surface-treated visible light-scattering titanium dioxide particles, the (f) dispersing aid being a polymer having protonated nitrogen atoms, and present in the finish composition in an amount of at least 0.2 wt% and up to and including 50 wt%, based on the total weight of the (c) surface-treated visible light-scattering titanium dioxide particles.

[0038] Further, a method for providing an inkjet receptive medium according to the present application comprises, in order:

[0039] A) providing a substrate; and

[0040] B) disposing an aqueous composition onto at least one surface of the substrate to provide a topcoat composition on the at least one substrate surface, wherein the aqueous composition has at least 2% solids and up to and including 90% solids, and comprises the following (a), (b), and (c) components:

[0041] (a) water-soluble salts of one or more polyvalent metal cations, the (a) one or more water-soluble salts being present in an amount of at least 0.5 wt% and up to and including 30 wt%;

[0042] (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder materials, present in an amount of at least 0.1 wt% and up to and including 30 wt%; and

[0043] (c) visible light-scattering particles that have been surface-treated such that the aqueous composition has a stable zeta potential greater than +4 millivolts, and the (c) surface-treated visible light-scattering particles are present in an amount of at least 5 wt% and up to and including 60 wt%,

[0044] wherein the amounts of (a), (b), and (c) components are based on the total weight of the aqueous composition,

[0045] to provide an inkjet receptive medium having a topcoat composition on the at least one substrate surface, the topcoat composition having a dry solids coating weight of at least 0.1 g / m 2 and up to and including 10 g / m 2 .

[0046] In some embodiments of the method of the present application, the substrate comprises a transparent or translucent polymeric film, and the method comprises disposing the aqueous composition such that the resulting topcoat composition has a dry solids coating weight of at least 0.1 g / m 2 and up to and including 2 g / m 2 , and the aqueous composition has at least 5% solids and up to and including 70% solids, and a dynamic viscosity of at least 30 centipoise (30 mPa.s) and up to and including 800 centipoise (800 mPa.s) as measured using a Brookfield Spindle Viscometer at 25°C, and comprises the following (a), (b), (c), (d), (e), and (f) components:

[0047] (a) one or more water soluble salts of magnesium (+2), calcium (+2), barium (+2), or mixtures thereof, said (a) one or more water soluble salts being present in an amount of at least 1 wt% and up to and including 25 wt%, based on the total weight of the aqueous composition;

[0048] (b) one or more non-ionic or cationic water soluble or water dispersible polymeric binder materials comprising at least polyvinyl alcohol, polyvinyl amine, polyethylene imine, a copolymer derived at least in part from ethylene amine and ethylene alcohol, or a combination of two or more of these polymeric materials, said (b) one or more non-ionic or cationic water soluble or water dispersible polymeric binder materials being present in an amount of at least 1 wt% and up to and including 8 wt%, based on the total weight of the aqueous composition;

[0049] (c) visible light scattering particles comprising titanium dioxide particles that scatter visible light, which have been surface treated, and which exhibit a D 50 (median) particle size of at least 0.04 μιη and up to and including 2 μιη, as measured using a particle size analyzer that provides a volume weighted particle size distribution, and said (c) surface treated visible light scattering titanium dioxide particles being present in an amount of at least 10 wt% and up to and including 40 wt%, based on the total weight of the aqueous composition;

[0050] (d) particles that are different from all of the (c) component, said (d) particles having a Rockwell hardness of less than or equal to R75, and being present in an amount of at least 0.05 wt% and up to and including 3 wt%, based on the total weight of the aqueous composition;

[0051] (e) a cross-linkable polymeric material that is different from all of the (a), (b), (c), and (d) components, and said (e) cross-linkable polymeric material being present in an amount of at least 0.2 wt% and up to and including 8 wt%, based on the total weight of the aqueous composition; and

[0052] (f) a dispersing aid for the (c) surface treated visible light scattering titanium dioxide particles, said (f) dispersing aid being a polymer having protonated nitrogen atoms, and being present in an amount of at least 0.2 wt% and up to and including 50 wt%, based on the total weight of the (c) surface treated visible light scattering titanium dioxide particles.

[0053] Further, the inkjet printing method according to the present application comprises in sequence:

[0054] A) providing an inkjet receiving medium comprising a substrate and a topcoat composition disposed on a surface thereof, said topcoat composition comprising the following (a), (b), and (c) components:

[0055] (a) one or more water soluble salts of polyvalent metal cations, said (a) one or more water soluble salts being present in an amount of at least 0.4 wt% and up to and including 40 wt%;

[0056] (b) one or more non-ionic or cationic water soluble or water dispersible polymeric binder materials, present in an amount of at least 0.5 wt% and up to and including 90 wt%; and

[0057] (c) visible light scattering particles, which have been surface treated, and which are present in an amount of at least 6 wt% and up to and including 90 wt%,

[0058] wherein the amounts of (a), (b), and (c) components are based on the total weight of the topcoat composition; and

[0059] B) inkjet printing one or more aqueous pigment-based inks onto the topcoat composition to provide a pigment-based image or layer.

[0060] In some embodiments of the inkjet printing method of the present application, the substrate comprises a transparent or translucent polymeric film, and the topcoat composition has a dry solid coating weight of at least 0.2 g / m 2 and up to and including 2 g / m 2 and the topcoat composition comprises the following (a), (b), (c), (d), (e), and (f) components:

[0061] (a) one or more water soluble salts of magnesium (+2), calcium (+2), barium (+2), or mixtures thereof, said (a) one or more water soluble salts being present in an amount of at least 0.4 wt% and up to and including 40 wt% based on the total weight of the topcoat composition;

[0062] (b) one or more non-ionic or cationic water soluble or water dispersible polymeric binder materials comprising at least polyvinyl alcohol, polyvinyl amine, polyethylene imine, a copolymer derived at least in part from ethylene amine and ethylene alcohol, or a combination of two or more of these polymeric materials, said (b) one or more non-ionic or cationic water soluble or water dispersible polymeric binder materials being present in an amount of at least 2 wt% and up to and including 90 wt% based on the total weight of the topcoat composition;

[0063] (c) visible light scattering particles comprising titanium dioxide particles that scatter visible light, which have been surface treated, and which exhibit a D 50a (median) particle size, and the (c) surface-treated, visible light-scattering titanium dioxide particles are present in an amount of at least 6 weight percent and up to and including 90 weight percent, based on the total weight of the topcoat composition;

[0064] (d) particles different from all of the (c) components, the (d) particles having a Rockwell hardness of less than or equal to R75, and present in an amount of at least 0.06 weight percent and up to and including 10 weight percent, based on the total weight of the topcoat composition;

[0065] (e) a cross-linkable polymeric material different from all of the (a), (b), (c), and (d) components, and the (e) cross-linkable polymeric material is present in an amount of at least 0.1 weight percent and up to and including 20 weight percent, based on the total weight of the topcoat composition; and

[0066] (f) a dispersing aid for the (c) surface-treated, visible light-scattering titanium dioxide particles, the (f) dispersing aid being a polymer having protonated nitrogen atoms, and present in the topcoat composition in an amount of at least 0.2 weight percent and up to and including 50 weight percent, based on the total weight of the (c) surface-treated, visible light-scattering titanium dioxide particles.

[0067] Further, the method of the present invention for providing an inkjet printed article comprises, in order:

[0068] A') providing a substrate having a surface,

[0069] A") providing an inkjet receiving medium by disposing an aqueous composition onto the surface of the substrate to form a topcoat composition, the aqueous composition having at least 2 percent solids and up to and including 90 percent solids, and the aqueous composition comprising the following (a), (b), or (c) components:

[0070] (a) water-soluble salts of one or more polyvalent metal cations, the (a) one or more water-soluble salts being present in an amount of at least 0.5 weight percent and up to and including 30 weight percent;

[0071] (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder materials, present in an amount of at least 0.1 weight percent and up to and including 30 weight percent; and

[0072] (c) particles that scatter visible light, which have been surface-treated such that the aqueous composition has a stable zeta potential greater than +4 millivolts, and the (c) surface-treated, visible light-scattering particles are present in an amount of at least 5 weight percent and up to and including 60 weight percent,

[0073] wherein the amounts of the (a), (b), and (c) components are based on the total weight of the aqueous composition; and

[0074] B) inkjet printing one or more aqueous pigment-based inks onto the topcoat composition to provide a pigment-based image or layer.

[0075] The additional inventive articles provided by the present application comprise:

[0076] a substrate comprising a surface;

[0077] a topcoat composition disposed on the surface of the substrate, the topcoat composition comprising the following (a), (b), and (c) components:

[0078] (a) one or more water-soluble salts of polyvalent metal cations, the (a) one or more water-soluble salts being present in an amount of at least 0.4 wt% and up to and including 40 wt%;

[0079] (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder materials, present in an amount of at least 0.5 wt% and up to and including 90 wt%; and

[0080] (c) visible light-scattering particles that have been surface treated, and present in an amount of at least 6 wt% and up to and including 90 wt%,

[0081] wherein the amounts of (a), (b), and (c) components are based on the total weight of the topcoat composition; and

[0082] a pigment-based inkjet-printed layer or image disposed on top of the topcoat composition.

[0083] The present application provides a method for providing a relatively thin white (opaque) background on a variety of substrates, on which high quality inkjet-printed layers or images can be provided at high printing speeds. These inkjet-printed layers or images exhibit excellent adhesion to the white background layer, as well as excellent adhesion of the white background to the substrate. There is also excellent adhesion of non-inkjet-printed areas of the white background topcoat composition to any subsequently applied coating layers (e.g., protective overcoat clearcoat coating layers) or lamination adhesives.

[0084] These advantages can be achieved by forming the thin white or opaque layer or pattern in-line using inkjet printing, or they can be formed in a separate pre-treatment operation. In addition, the advantages of the present application are observed when using anionically stabilized aqueous pigment-based inks, and when using multi-station devices to obtain the inkjet-printed images, particularly during high speed commercial printing operations.

[0085] More specifically, the advantages described herein are realized using the inventive aqueous composition to pre-treat a substrate or to provide a topcoat layer to a substrate to impart an opaque "white" coating or image (pattern) followed by inkjet printing. Such aqueous compositions have the unique features described herein, namely, (a) a water-soluble salt of one or more polyvalent metal cations, (b) a suitable water-soluble or water-dispersible polymeric binder material, and (c) surface-treated visible light-scattering particles. The resulting inkjet receptive media provided using the present invention can exhibit an opacity of at least 30% as determined by the TAPPI 425 OP-16 test, and a colorimetric value defined by an a* value of at least -5 and up to and including +5 and a b* value of at least -5 and up to and including +5. BRIEF DESCRIPTION OF DRAWINGS

[0087] Figure 1 A partial cross-sectional view showing a simple embodiment of an inkjet receptive media according to the present invention is shown.

[0088] Figure 2 A partial cross-sectional view showing yet another embodiment of an inkjet receptive media according to the present invention comprising multiple layers is shown.

[0089] Figure 3 A partial cross-sectional view showing an inkjet printed article according to the present invention is shown. DETAILED DESCRIPTION

[0091] The following discussion relates to various embodiments of the present invention, and while some embodiments can be particularly directed toward specific uses, the disclosed embodiments should not be interpreted, or otherwise be deemed, to limit the scope of the invention as claimed below. In addition, those skilled in the art will appreciate that the following disclosure has broader application than the specific embodiments discussed.

[0092] DEFINITIONS

[0093] As used herein to define the various components of the aqueous composition for pre-treatment, topcoat composition, aqueous pigment-based ink, and other materials used in the practice of the present invention, the singular forms "a," "an," and "the" are intended to include one or more components (i.e., to include the plural), unless otherwise indicated.

[0094] Terms not specifically defined herein should be understood to have the meanings commonly used by those of skill in the art. If a term is defined differently elsewhere in this application, that term is used in the context of the present application.

[0095] The use of numerical values in the various ranges specified herein should be considered as approximations as if the word "about" were to precede the minimum and maximum values of each range. In this manner, slight variations above and below the stated ranges can be useful to achieve substantially the same results as the stated values within the range. Also, these ranges are intended to encompass any and all derived or sub-ranges of the ranges specified. Unless otherwise indicated, the disclosure of these ranges is intended as a continuous range including each and every value and sub-range therein.

[0096] The parameter "acid value" (also referred to as acid number) as used herein is defined as the number of milligrams (mg) of potassium hydroxide required to neutralize 1 g of the described acidic polymer.

[0097] The term "aqueous" in the aqueous composition, the aqueous organic pigment dispersion and the aqueous pigment-based ink according to the present application means that the water content is greater than 60 wt.-% or at least 80 wt.-% based on the total weight of all solvents. Thus, water is the main solvent in such compositions.

[0098] The Rockwell hardness values of many polymeric materials are known from literature published online by Plastics International (http: / / www.plasticsintl.com) and the values can be measured according to ASTM D785-51.

[0099] The median particle size (D 50 ) in micrometers (pm) as equivalent spherical diameter (ESD) particle size can be determined using a Horiba Particle Size Distribution Analyzer (Horiba Semiconductor) using the procedure required by the instrument, which provides a volume weighted particle size distribution. The term D 95 or the 95th percentile particle size refers to a fractionated particle size distribution such that 95% of the particles have a diameter less than the indicated diameter. Similarly, the term D 50 or the 50th percentile particle size (or median particle size) refers to a fractionated particle size distribution such that 50% of the particles have a diameter less than the indicated diameter. Such particle size measurements can be made using laser diffraction (static) techniques or dynamic light scattering techniques. However, for the purposes of the present application (including the working examples below), D 50 and any D 95 particle size values are obtained using a commercially available Horiba particle size analyzer (Model LA-920) which provides particle size values from a volume weighted particle size distribution.

[0100] Other particle size measurement techniques and equipment are also known in the art. For example, laser diffraction techniques will also provide a volume-weighted particle size distribution. Dynamic light scattering techniques will provide an intensity-weighted particle size distribution. One such device used for this purpose is the Nanotrac 150 NPA Ultrafine Particle Analyzer (Microtrac, Inc.). Standard procedures for using such a device are described in the National Institute of Standards and Technology (NIST) Special Publication 1200-6, Measuring the Size of Nanoparticles in Aqueous Media Using Batch-Mode Dynamic Light Scattering NIST-NCL Joint Assay Protocol, PCC-1 Version 1.2, May 2015 and ISO 22412:2017 Particle Size Analysis - Dynamic Light-Scattering (DLS).

[0101] For the purposes of the present application, the "zeta potential" can be measured using a "Malvern Zetasizer Nano-ZS" (zEN) device (Malvern Pananalyticals). This equipment is used to obtain the zeta potential from the electrophoretic mobility of the particles measured. The samples are analyzed in the undiluted state. The zeta potential is measured using a measurement technique, a combination of electrophoresis and laser Doppler velocity measurement, sometimes called laser Doppler electrophoresis. This method measures how fast the particles move in a liquid when an electric field is applied, i.e. it measures the particle velocity.

[0102] The term "water-soluble" when used in relation to a salt involving a polyvalent metal cation means a water solubility of at least 0.5 g of salt in 100 ml of water at 20 °C.

[0103] Dynamic viscosity can be measured by any well-known technique. Preferred methods include measuring the mass flow rate through a capillary, such as in a capillary viscometer, or measuring the falling ball velocity through a fluid, for example using a rolling ball viscometer. Both capillary flow viscometers and commercially available Anton Paar Automated MicroViscometer (AMVn) employing rolling ball technology can be used to measure the dynamic viscosity reported herein. All dynamic viscosity values disclosed herein are measured under gravity-induced shear at about 24°C-26°C. It will be understood that the values quoted are reported in centipoise (cP) or millipascal-seconds (mPa.s), and 1 cP = 10 -3 Pascal-seconds (Pa.s) equals 10 -2 dynes-seconds / cm 2 While viscosities can be measured with high precision, the viscosity values herein are reported to one or two decimal places only, and they are generally rounded values rather than truncated values. All claims reciting dynamic viscosity are intended to be interpreted in terms of values in mPa.s, generally rounded to one decimal place.

[0104] The Wilhelmy plate method is a well-known technique for measuring the static surface tension of a fluid at a solid interface. The technique involves a plate, typically chosen from roughened platinum alloy, of known dimensions, suspended on a balance. The plate is brought into contact with the fluid of interest, and a vertical force is applied to the plate to form a liquid meniscus between the fluid and the plate. The resulting surface tension is given according to equation (1):

[0105] (1) σ = F / L cos(θ)

[0106] where σ is the surface tension of the liquid, F is the force acting on the balance (millinewtons / meter), L is the wetted length of the plate in millimeters, and θ is the contact angle between the plate and the fluid.

[0107] Typically, roughened platinum results in a contact angle very close to zero, and the cosine of θ tends to 1. A complete theoretical treatment of the method can be found in, for example, "A Method for Determining Surface and Interfacial Tension Using a Wilhelmy Plate", Colloid and Polymer Science, 255(7), pp. 675-681. Many commercially available instruments are known for measuring surface tension, however, the instrument used in the present invention for reporting surface tension values is a Krüss Model K10ST tensiometer.

[0108] The phrase "particles that scatter visible light" refers to pigments or other water-insoluble particles that uniformly scatter visible light such that when present as a uniform layer on a surface, the layer will appear white and block transmission of light from the underlying surface. The degree to which the layer obscures the underlying surface determines the relative "opacity" of the layer.

[0109] The opacity of a printed white ink layer is generally defined as the ratio of the CIE tristimulus values (Y) of the white layer measured over a black background (Y b ) to the same measurement of the white layer (Y w ) over a white background. Instruments for measuring opacity in this manner are available from Hunter Labs, and the opacity when measured by this known technique is generally referred to as Hunter Opacity: Hunter Opacity = 100 x (Y b / Y w ).

[0110] The opacity of the inkjet receiving media according to the present application can also be defined as the ratio of the visual reflectance (R b ) of the coated white topcoat composition used in the present application measured over a black background to the same measurement of the same coated white topcoat composition (R w ) over a white background. This opacity is determined using the TAPPI 425 OP-16 Opacity Test: e.g. Opacity = 100 * (R b / R w ). This standard opacity parameter is described in more detail by consulting the TAPPI standard for opacity, which is available online at TAPPI.org or in various publications. This opacity parameter is measured and used for all of the working examples shown below.

[0111] The CIELAB L*, a*, and b* values described herein have the known definitions according to the CIE 1976 color space or corresponding later known published versions of the color space, and are determined using the standard D65 illuminant and known procedures. These values can be used to express color in three numerical values: L* for the lightness (or value) of the color, a* for the green-red component of the color, and b* for the blue-yellow component of the color value.

[0112] For purposes of clarity with respect to the definition of any term relating to polymers, reference should be made to the "Glossary of Basic Terms in Polymer Science", Pure Appl. Chem. 68, 2287-2311 (1996) published by the International Union of Pure and Applied Chemistry ("IUPAC"). However, any definition expressly set forth herein shall be deemed controlling.

[0113] The term "polymer" as used herein is used to describe a compound having a relatively large molecular weight formed by linking together many small reactive monomers. As the polymer chain grows, it coils upon itself in a random fashion to form a coiled structure. With the selection of solvent, the polymer can become insoluble as the chain length grows and become a polymer particle dispersed in the solvent medium. These particle dispersions can be quite stable and are useful in being described as the topcoat composition used in the present invention. In the present invention, the term "polymer" refers to a non-crosslinked material unless otherwise indicated. Thus, the difference between a crosslinked polymer particle and a non-crosslinked polymer particle is that the latter can be dissolved in certain organic solvents having good solvating properties, whereas the crosslinked polymer particle can swell but not dissolve in the organic solvent due to the strong covalent linkages of the polymer chains.

[0114] The term "copolymer" refers to a polymer composed of two or more different repeating units arranged along or pendant from the polymer backbone.

[0115] The term "backbone" refers to a chain of atoms in a polymer to which a plurality of side groups can be attached. An example of such a backbone is a "all-carbon" backbone obtained from the polymerization of one or more ethylenically unsaturated polymerizable monomers.

[0116] The repeating units in some of the polymers described herein are generally derived from the corresponding ethylenically unsaturated polymerizable monomers used in the polymerization process, which can be obtained from various commercial sources or prepared using known chemical synthesis methods. For other polymers described herein, the repeating units in the living polymer can be the result of subsequent chemical reactions using the original repeating units used to prepare the polymer. For example, polyvinyl alcohol is derived from the hydrolysis of preformed polyvinyl acetate, which in turn is prepared from the polymerization of vinyl acetate.

[0117] The term "wt.%" means the amount of a component or material based on the total weight of the aqueous composition, aqueous formulation, or dry layer, unless otherwise indicated.

[0118] As used herein, the term "layer" or "coating" can be comprised of one layer disposed or applied or a combination of several successive layers or combinations of sub-layers disposed or applied. Such layers or coatings are non-porous unless otherwise noted and contact the specific area of the substrate to which they are applied.

[0119] Percent (%) solids refers to the weight percent of non-volatile material in a composition or solution, which can be determined using known gravimetric procedures.

[0120] Use

[0121] The aqueous compositions described herein can be used to provide an opaque, inkjet printable medium ("inkjet receiving medium") that can be advantageously used in aqueous inkjet printing processes, including those utilizing high speed inkjet printing systems and anionically stabilized aqueous pigment-based inks.

[0122] Aqueous "pretreatment" compositions

[0123] The aqueous pretreatment compositions according to the present application (or "aqueous topcoat compositions" or simply "aqueous compositions") generally have a solids content of at least 2% or at least 5%, and up to and including 70%, or up to and including 90%. Flexographic and gravure coating and inkjet printing techniques can require different optimal % solids to achieve the most desirable topcoat composition layer or pattern at the target opacity and dry thickness according to the present application.

[0124] The aqueous compositions according to the present application can have a dynamic viscosity of less than or equal to 2000 centipoise (2000 mPa.s) or at least 30 centipoise (30 mPa.s) and up to and including 800 centipoise (800 mPa.s) as measured at 25°C using a commercially available Brookfield rotational viscometer (Model LV DV+, using a SC4-18 spindle). Such viscometers with the requisite set of spindles are available from various commercial sources.

[0125] The aqueous compositions should include the three essential (a), (b), and (c) components as defined below in order to achieve the benefits of the opaque thin coating for the inkjet receiving medium of the present application as described herein. Such aqueous compositions can also include one or more of the optional (d), (e), and (f) components described below, and in some particularly useful embodiments, at least the (e) and (f) components are present together with the essential (a), (b), and (c) components, and in other embodiments, all of the (d), (e), and (f) components are present together with the essential (a), (b), and (c) components.

[0126] More specifically, the aqueous composition should contain (a) one or more water-soluble salts of polyvalent metal cations as an essential component. Mixtures of such salts have the same polyvalent metal cations, and mixtures of salts having different polyvalent cations can be used in any desired proportions. Typically, these salts are each colorless, and do not react with other materials in the aqueous composition.

[0127] Useful (a) one or more water-soluble salts can comprise one or more polyvalent cations, such as magnesium (+2), calcium (+2), barium (+2), zinc (+2), or aluminum (+3), or mixtures thereof. Magnesium (+2), calcium (+2), and barium (+2) cations, or combinations thereof, in combination with suitable counterions, are particularly useful.

[0128] Examples of useful (a) one or more water-soluble salts of polyvalent metal cations include, but are not limited to, calcium chloride, calcium acetate, calcium nitrate, magnesium chloride, magnesium acetate, magnesium nitrate, barium chloride, barium nitrate, zinc chloride, zinc nitrate, aluminum chloride, aluminum hydroxychloride, and aluminum nitrate. Hydrated forms of these salts can also be used. Other useful (a) water-soluble salts will be readily apparent to the skilled artisan. Particularly useful (a) water-soluble salts of polyvalent metal cations include one or more of CaCl2, Ca(CH3CO2)2, MgCl2, Mg(CH3CO2)2, Ca(NO3)2, or Mg(NO3)2, or hydrated forms of these salts.

[0129] The amount of (a) water-soluble salts of polyvalent metal cations in the aqueous composition can be sufficient to provide at least 0.1 wt.%, at least 0.5 wt.%, or even at least 1 wt.%, and up to and including 25 wt.% or up to and including 30 wt.% solids, based on the total weight of the aqueous composition according to the present application.

[0130] Another essential component of the aqueous composition is (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder materials (identified herein and especially also in the working examples below as "binder materials"). Such binder materials can include, but are not limited to, polyvinyl alcohol, polyethyleneimine (including protonated polyethyleneimine), polyethylene oxide, polyvinyl amine, copolymers derived at least in part from ethylene alcohol and ethylene oxide, copolymers derived at least in part from ethylene amine and ethylene alcohol, polyvinyl pyrrolidone, cellulosic materials (including cellulose and its derivatives, such as hydroxycellulose), gelatin and its derivatives, starch, cationic polyelectrolytes, polyurethanes, and silanol-modified polyvinyl alcohol. Combinations of two or more of such binder materials can also be used. Such binder materials are generally capable of absorbing water, and are additionally capable of forming a continuous phase solution.

[0131] For example, useful (b) non-ionic or cationic water-soluble or water-dispersible polymeric binder materials can be acetoacetate-modified polyvinyl alcohol. In crosslinked form, such (b) components in the resulting topcoat composition provide wet abrasion resistance as well as increased cohesion in the dried layer.

[0132] Alternatively, (b) one or more non-ionic or cationic water-soluble or water- dispersible polymeric binder materials can comprise at least polyvinylamine, polyethyleneimine, polyvinyl alcohol, a copolymer derived at least in part from vinylamine and vinyl alcohol, or a combination of two or more of these binder materials.

[0133] More generally, (b) one or more non-ionic or cationic water-soluble or water- dispersible polymeric binder materials can be selected from polyvinyl alcohol, polyethylene oxide, polyvinylamine, a copolymer derived at least in part from vinyl alcohol and ethylene oxide, a copolymer derived at least in part from vinylamine and vinyl alcohol, or a combination of two or more of these binder materials.

[0134] Useful cationic polyelectrolytes that can be used in this manner can include amidine moieties, polyamide-epichlorohydrin polymers, polyamine solution polymers, as described in U.S. Patent 9,067,448 (Dannhauser et al.) at columns 9-10.

[0135] Useful polyurethanes for this purpose can be a dispersion of polyurethane particles in an aqueous medium, for example, as also described in U.S. Patent 9,067,448 (column 10, lines 36-48). Useful silanol-modified polyvinyl alcohols are also described in U.S. Patent 9,067,448 (column 10, lines 49-68).

[0136] It is possible that (b) one or more non-ionic or cationic water-soluble or water- dispersible polymeric binder materials can be selected such that they are also useful for surface treatment or formation of (c) surface-treated light-scattering particles as described in more detail below. Particularly useful binder materials for this purpose include, but are not limited to, polymers having protonated nitrogen atoms, such as polyvinylamine, protonated polyethyleneimine, and copolymers derived at least in part from vinylamine and vinyl alcohol.

[0137] The (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder materials can be present in the aqueous composition in an amount of at least 0.1 wt% or at least 1 wt%, and up to and including 8 wt% or up to and including 30 wt%, based on the total weight of the aqueous composition.

[0138] Further, the aqueous composition should include as another essential component (c) visible light scattering particles that have been surface treated (i.e., "(c) surface treated visible light scattering particles") as described herein having a D50 of at least 0.04 μιη and up to and including 0.5 μιη or up to and including 2 μιη as determined using a particle sizer that provides a volume weighted particle size distribution as described above. 50 (median) particle size.

[0139] In some cases as observed in the working examples below, D50 of the visible light scattering particles can be obtained that are greater than 2 μιη. In such cases, such particles are outside the scope of the present application even though they still pass the "salt" test and provide the desired zeta potential in the aqueous composition. It can be desirable to mill such larger visible light scattering particles to reduce their D50 to 2 μιη or less. 50 (median) particle size greater than 2 μιη and surface treated visible light scattering particles, in which case such particles are outside the scope of the present application even though they still pass the "salt" test and provide the desired zeta potential in the aqueous composition. It can be desirable to mill such larger visible light scattering particles to reduce their D50 to 2 μιη or less. 50 (median) particle size to 2 μιη or less.

[0140] Useful materials that can serve as visible light scattering particles include, but are not limited to, silica, zinc oxide, titanium dioxide, zirconium oxide, aluminum oxide, barium sulfate, magnesium oxide, or a combination of two or more of these materials. All of these visible light scattering particles can be surface treated in the manner mentioned below. Particularly useful (c) surface treated visible light scattering particles comprise surface treated visible light scattering titanium dioxide particles.

[0141] It is possible to surface treat the visible light scattering particles using one or more (f) dispersion aids described below. This can be accomplished by mixing the visible light scattering particles with one or more (f) dispersion aids in a suitable solvent, such as water. The order of addition can vary. For example, the visible light scattering particles can first be dispersed into the solvent, followed by the addition of the (f) dispersion aid. The reverse order of addition can also be effective. However, in a one pot formulation, it is generally recommended to add both the (c) surface treated visible light scattering particles and the (f) dispersion aid after the addition of the (a) one or more water soluble salts of polyvalent cations. A positively charged solid material can also be used to provide a shell to the resulting (c) surface treated visible light scattering particles to make the surface charge of the particles cationic. For example, the visible light scattering titanium dioxide particles can be surface treated using alumina in an amount of at least 1 wt% and up to and including 10 wt% based on the total weight of the surface treated visible light scattering titanium dioxide particles.

[0142] The effect of such surface treatment is to give the aqueous composition a stable zeta potential of greater than +4 millivolts (mV) or greater than +5 mV or even greater than +10 mV over the intended lifetime of the aqueous composition containing (c) surface treated visible light scattering particles according to the present application.

[0143] The (c) surface treated visible light scattering particles can be present in an amount of at least 5 wt% or at least 10 wt% and up to and including 40 wt% or up to and including 60 wt% based on the total weight of the aqueous composition.

[0144] The three essential (a), (b) and (c) components mentioned above can be mixed in the appropriate proportions, at the appropriate temperatures, and in the appropriate order to obtain the aqueous composition according to the present application. Representative examples of useful aqueous compositions are provided below in the working examples.

[0145] While not essential to achieve the desired advantages of the present application, the aqueous composition according to the present application can optionally comprise (d) particles having a Rockwell hardness of less than or equal to R90 or less than or equal to R75. Rockwell hardness can be measured as described above. These (d) particles are distinct from the (c) component described above.

[0146] Useful (d) particles can be selected from a variety of wax particles and other sufficiently soft polymeric particles. Specific examples include, but are not limited to, particles of polyethylene, polytetrafluoroethylene, polypropylene, ethylene bis-stearamide, synthetic hydrocarbon waxes, carnauba wax, and combinations of two or more types of these materials.

[0147] Some particularly useful (d) particles comprise (i) domains of a first organic polymer and (ii) domains of a second organic polymer, the domains of the two organic polymers being uniformly or non-uniformly dispersed within the domains of the first organic polymer. In addition, the first organic polymer has a lower melting point than the second organic polymer (at least 30 °C).

[0148] The weight ratio of (i) the first organic polymer to (ii) the second organic polymer is selected such that the (d) particles have a density of at least 1.0 g / ml and up to and including 1.50 g / ml, or more likely at least 1.05 g / ml and up to and including 1.35 g / ml, or even at least 1.05 g / ml and up to and including 1.20 g / ml. Particle density can be measured using known procedures and equipment (e.g., gas pycnometry or mercury porosimetry).

[0149] Useful polymeric materials that can form (i) the first organic polymeric microdomains include, but are not limited to, polyethylene, polypropylene, ethylene bis-stearamide, polyethylene-polypropylene copolymers, carnauba wax, synthetic hydrocarbon waxes (especially those produced by the Fischer-Tropsch process as described by H. Bennett in Industrial Waxes, Volume 1), polyamides, and combinations of two or more of these materials.

[0150] Useful polymeric materials that can form (ii) the second organic polymeric microdomains include, but are not limited to, polytetrafluoroethylene (PTFE or Teflon).

[0151] (d) The mode average equivalent spherical diameter (ESD) particle size of the particles can be at least 2 μιη or at least 3 μιη and up to and including 8 μιη or up to and including 12 μιη. The ESD of such particles can be adjusted so that it is at least 0.1 μιη or at least 0.2 μιη greater than the sum of the dry thickness of the topcoat composition (described below) and any dry inkjet printed image or layer (described below).

[0152] Useful (d) particles are typically present in the aqueous composition in an amount of at least 0.02 wt% or at least 0.05 wt% and up to and including 3 wt% or up to and including 5 wt%, based on the total weight of the aqueous composition.

[0153] Another optional but desirable component in the aqueous composition is an (e) cross-linkable polymeric material that is different from all of the (a), (b), (c), and (d) components. Useful (e) cross-linkable polymeric materials of this type include those described in

[0029] and

[0030] of U.S. Patent Application Publication 2011 / 0279554 (Dannhauser et al.). For example, useful (e) cross-linkable polymeric materials can include, but are not limited to, gelatin, polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl amine, polyvinyl imine, starch, hydroxyl cellulose materials, and derivatives of such materials. Mixtures of two or more such (e) cross-linkable polymeric materials can be used as desired.

[0154] It can be useful to include one or more cross-linking agents in the aqueous composition to facilitate cross-linking of the (e) cross-linkable polymeric material present. The identity and amount of the cross-linking agent will depend on the choice of (e) cross-linkable polymeric material and its reactivity with the cross-linking agent, the number of cross-linking sites available, its compatibility with other materials in the aqueous composition, and manufacturing constraints such as solution shelf life and coating dry speed. Representative cross-linking agents include, but are not limited to, glyoxal, TSI and EPI (Clariant), SEQUAREZ TM755 (Omnova), glutaraldehyde sodium bisulfite complex (Aldrich), Sunrez 700M and 700C (Omnova), bis(vinyl)sulfone, bis(vinyl)sulfone methyl ether, adipic dihydrazide, epichlorohydrin polyamide resin, and urea-formaldehyde resin.

[0155] The amount of the one or more (e) crosslinkable polymeric materials in the aqueous composition can be at least 0.1 wt% or at least 0.2 wt%, and up to and including 8 wt% or up to and including 30 wt%, based on the total weight of the aqueous composition according to the present application.

[0156] Yet another optional but desirable component in the aqueous composition is (f) a dispersion aid for the (c) surface-treated visible light-scattering particles, which (f) dispersion aid is cationic on a cumulative charge basis and is different from the (a) one or more water-soluble salt of a polyvalent cation, but the (f) dispersion aid can be the same or different from the (b) one or more nonionic or cationic water-soluble or water-dispersible polymeric binder material used in the aqueous composition. Thus, the (b) one or more nonionic or cationic water-soluble or water-dispersible polymeric binder material can also function as the (f) dispersion aid or “surface treatment” material for providing the surface treatment of the (c) surface-treated visible light-scattering particles.

[0157] Useful (f) dispersion aids can be polymers having at least one protonated nitrogen atom, including but not limited to protonated polyvinylamine, protonated polyethyleneimine, a copolymer derived at least in part from vinylamine, or a combination of two or more of such materials. Protonated polyvinylamine and copolymers derived at least in part from vinylamine are particularly useful. For example, useful protonated polyvinylamine is described in U.S. Patent 9,067,448 (referenced above) in column 10 (line 21 fr), and a commercially available example is identified as Lupamin® 159 (A) (BASF). In some embodiments, protonated polyethyleneimine can be a particularly useful (f) dispersion aid, and a commercially available material of this type is Lupamin® 159 (A) available from BASF. Lupamin® 159 (B) is a non-protonated polyethyleneimine and is not useful as a (f) dispersion aid in the present application. Lupamin® 159 (A) (BASF). In some embodiments, protonated polyethyleneimine can be a particularly useful (f) dispersion aid, and a commercially available material of this type is Lupamin® 159 (A) available from BASF. Lupamin® 159 (B) is a non-protonated polyethyleneimine and is not useful as a (f) dispersion aid in the present application.

[0158] The (f) dispersion aid can be present in an amount of at least 0.2 wt.%, or at least 1 wt.%, and up to and including 15 wt.%, or up to and including 20 wt.%, or even up to and including 50 wt.%, based on the total weight of the (c) surface-treated visible light-scattering particles. In those embodiments where the (f) dispersion aid is the same as the (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder material, the amount of (f) dispersion aid present in the aqueous composition can be greater than the amount required for sufficient surface treatment of the visible light-scattering particles.

[0159] The aqueous composition can further comprise one or more of the following optional materials: a surfactant, an anti-corrosion compound, a biocide, a preservative, an antifoam agent, or any combination of two or more of these materials.

[0160] The aqueous composition can be prepared by mixing the necessary (a), (b), and (c) materials together with the various optional components and materials described above, in the aqueous medium which is primarily water, in amounts to provide the % solids mentioned above, in the desired order of mixing, and using suitable equipment. At least 50 wt.%, or at least 70 wt.%, or even at least 90 wt.% of the aqueous medium consists of water, based on the total weight of all solvents in the aqueous medium.

[0161] Some particularly useful embodiments according to the present application include aqueous compositions for pre-treating a substrate prior to inkjet printing on the substrate, each aqueous composition having at least 5% solids and up to and including 50% solids, or up to and including 70% solids, and a dynamic viscosity of at least 30 centipoise (30 mPa.s) and up to and including 800 centipoise (800 mPa.s), or up to and including 1200 centipoise (1200 mPa.s), or up to and including 2000 centipoise (2000 mPa.s), as measured at 25°C using a Brookfield rotational viscometer,

[0162] The aqueous composition comprises the following components (a) to (f):

[0163] (a) one or more water-soluble salts of magnesium (+2), calcium (+2), barium (+2), or mixtures thereof, present in an amount of at least 1 wt.% and up to and including 25 wt.%, based on the total weight of the aqueous composition;

[0164] (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder materials comprising at least polyvinyl alcohol, polyvinyl amine, polyethylene imine, a copolymer derived at least in part from vinyl amine and vinyl alcohol, or a combination of two or more of these polymeric materials, the (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder materials being present in an amount of at least 0.1 wt% or at least 1 wt%, and up to and including 8 wt% or up to and including 30 wt%, based on the total weight of the aqueous composition;

[0165] (c) visibly light-scattering particles comprising visibly light-scattering titanium dioxide particles that have been surface treated such that the aqueous composition has a stable zeta potential greater than +4 millivolts (mV) or greater than +10 millivolts (mV), wherein the (c) surface treated visibly light-scattering titanium dioxide particles exhibit a D 50 (median) particle size of at least 0.2 pm and up to and including 0.5 pm, and are present in an amount of at least 5 wt% or at least 10 wt%, and up to and including 40 wt% or up to and including 60 wt%, based on the total weight of the aqueous composition;

[0166] (d) particles different from the (c) component, the (d) particles having a Rockwell hardness less than or equal to R75, and being present in an amount of at least 0.05 wt% and up to and including 3 wt% or up to and including 5 wt%, based on the total weight of the aqueous composition;

[0167] (e) a cross-linkable polymeric material different from all of the (a), (b), (c), and (d) components, the (e) cross-linkable polymeric material being present in an amount of at least 0.1 wt% or at least 0.2 wt%, and up to and including 8 wt% or up to and including 30 wt%, based on the total weight of the aqueous composition; and

[0168] (f) a dispersion aid for the (c) surface treated visibly light-scattering titanium dioxide particles, the (f) dispersion aid being a polymer having protonated nitrogen atoms, and being present in an amount of at least 0.2 wt% or at least 1 wt%, and up to and including 20 wt% or up to and including 50 wt%, based on the total weight of the (c) surface treated visibly light-scattering titanium dioxide particles.

[0169] Inkjet receiving medium

[0170] As Figure 1As shown in the center, a simple embodiment according to the present application is an inkjet receptive medium 10 having a substrate 100, a topcoat composition 110 disposed on the substrate 100, and the substrate 100 and topcoat composition 110 adjacent to or in direct contact with each other. In general, the substrate 100 can be opaque, semi-transparent, translucent, or transparent, although transparent or translucent or even reflective metallized polymeric films are particularly useful for the opacity provided by the topcoat composition 110 described herein.

[0171] Suitable substrates can generally be flat in nature, having two opposing surfaces or support sides. The substrate can have a single "layer" or be composed of multiple layers of the same or different materials. In most cases, the substrate comprises a primary material, such as a transparent polymeric material coated or laminated with one or more other types of materials, such as polymeric coatings or metal layers.

[0172] Useful substrate materials from which the substrate 100 can be constructed include, but are not limited to, glossy, semi-gloss, or matte coated offset papers, which generally comprise a paper base (support) that has been coated with clay or similar materials and has undergone a surface calendering process to provide the desired surface smoothness. Such substrates include both glossy coated offset papers and matte coated offset papers, and are available from a variety of commercial sources, including, for example, International Paper, Sappi, NewPage, Appleton Coated, Abitibi-Bowater, Mohawk Papers, Verso, Mitsubishi, Norpac, Domtar, and others readily known to the skilled artisan.

[0173] In some embodiments, the substrate material can be readily hydrophilic and capable of absorbing and transferring aqueous pigment-based ink colorants, such as pigment colorants, into the interior of the substrate, before the topcoat composition is disposed thereon, such as coated thereon, with the aqueous compositions described herein. For example, such hydrophilic substrates can be porous.

[0174] Alternatively, the substrate can have a hydrophobic surface prior to the opaque topcoat composition being disposed thereon. The hydrophobic surface can be substantially impermeable or impermeable to aqueous pigment-based ink compositions. Thus, the topcoat composition can provide an opaque, hydrophilic surface relative to the hydrophobic surface of such substrates.

[0175] Other useful substrates include coated and uncoated offset papers and other plain papers, and any other material commonly used as an inkjet receiving medium, such as resin-coated paper, polyester film, microporous materials, such as those containing polyethylene, composite films, coated and uncoated plain paper, synthetic paper, photographic paper support, melt-extrusion coated paper, and laminated paper, such as biaxially oriented support laminates, such as those described in Column 6 (line 50) to Column 7 (line 2) of U.S. Patent 9,067,448 (referenced above). While many of the substrates referenced herein are not opaque in nature, the present application is particularly useful when the opaque substrate is a dark color (in which case, it would be difficult to observe a subsequently inkjet-printed image without first applying the white opaque aqueous composition of the present application).

[0176] If a water-impermeable (hydrophobic) substrate such as a transparent, translucent, or metallized (coated with a metal layer) polymeric film is used in accordance with the present application, the surface to be coated can be modified to increase the static surface energy to greater than 45 dynes / cm (or at least 50 dynes / cm and up to and including 60 dynes / cm) prior to deposition of the topcoat composition in order to provide sufficient wettability for the application of the aqueous composition and formation of the topcoat composition. Surface energy modification can be performed using corona discharge treatment (CDT), plasma discharge treatment, flame ionization treatment, atomic layer deposition, or similar treatments known in the art.

[0177] Figure 2 Another embodiment according to the present application is exemplified in which the inkjet recording medium 20 comprises a support 200 which can be water-impermeable and an optional first layer 210 disposed on at least one surface of the support 200, which together form a substrate 215 for an inkjet receiving medium according to the present application. The first layer 210 can comprise a water-based tie layer composition (described below) and underlie the topcoat composition 220. In many embodiments, the support 200 can consist of a water-impermeable material, such as a transparent or translucent polymeric film or a co-extrudate or laminate of two (or) more transparent or translucent polymeric films as referenced above in U.S. Patent 9,067,448 (Columns 6-7). While the topcoat composition 220 generally provides excellent adhesion to most supports 200 without the need for a separate first layer 210, there can be supports for which the first layer 210 can be used to enhance adhesion of the topcoat composition 220 to the support 200.

[0178] In some embodiments, the substrate comprises a transparent or translucent polymeric film or a co-extrudate or laminate of two or more transparent or translucent polymeric films. This type of material can be readily obtained from various commercial sources.

[0179] The first layer 210 can be referred to in the art as a "tie layer" and is typically water-based, meaning that it is provided by an aqueous formulation, and serves to improve the adhesion of the topcoat composition 220 to the support 200 (when the support 200 is composed of a hydrophobic material such as a transparent or translucent polymeric film (e.g., a polyester film) or a polyethylene-coated paper). Examples of hydrophilic materials useful in constituting the first layer 210 (or tie layer) include, but are not limited to, halogenated phenols, partially hydrolyzed vinyl chloride-vinyl acetate copolymers, partial vinylidene chloride-methyl acrylate-itaconic acid terpolymers, partial vinylidene chloride-acrylonitrile-itaconic acid terpolymers, and glycidyl (meth)acrylate polymers. Other useful materials include any polymer, copolymer, reactive polymer and copolymer, and mixtures thereof, which exhibit effective adhesion between the topcoat composition and the substrate. Also useful are water-soluble or water-dispersible polymers including, but not limited to, polyvinyl alcohol, polyvinyl amine, polyvinyl pyrrolidone, gelatin and gelatin derivatives, cellulose ethers, polyoxazolines, polyvinyl acetamide, partially hydrolyzed polyvinyl acetate / polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyalkylene oxides, sulfonated or phosphonated polyesters or polystyrenes, casein, zein, albumin, chitin, chitosan, dextran, pectin, collagen derivatives, xanthan gum, agar, arrowroot, guar gum, carrageenan, tragacanth gum, xanthan gum, rhamsan, and various polymeric lattices. Particularly useful tie layer materials are polyvinyl alcohol, polyvinyl amine, gelatin or gelatin derivatives, polyethylene imine, epoxy resins, polyurethanes, polyacrylamide and derivatives or copolymers thereof, and mixtures of any of these materials.

[0180] While the first layer 210 can be a single discrete layer, it can also comprise two or more water-based sub-layers, each sub-layer comprising the same or different hydrophilic material described above.

[0181] The total dry coverage of the one or more hydrophilic materials in the first layer 210 (or tie layer), whether composed of a single discrete layer or multiple sub-layers, can be at least 0.05 g / m2 2 and up to and including 12 g / m2 2 , or at least 0.05 g / m2 2 and up to and including 8 g / m2 2 , or at least 0.05 g / m2 2 and up to and including 3 g / m2 2 .

[0182] Further details regarding the structure and materials of the first layer 210 (or tie layer) are provided in U.S. Patent 9,376,582 (Dannhauser et al.).

[0183] In still other embodiments of the inkjet recording media (not illustrated) according to the present application, a topcoat composition can be disposed on each of the opposed surfaces of the substrate, and the individual topcoat compositions can be composed of the same or different combinations of materials, can have the same or different average dry thicknesses, or can be formed using the same or different methods.

[0184] The inkjet receptive media prepared according to the present application can comprise a substrate having an L* value of 50 or less, or even 40 or less.

[0185] Further, the inkjet receptive media prepared according to the present application can have an opacity of at least 30% or at least 50% as determined using the TAPPI 425 OP-16 Opacity Test described above, and can have a colorimetry defined by the following parameters: an a* value of at least -5 and up to and including +5, and a b* value independently of at least -5 and up to and including +5, or more likely an a* and b* value each independently of at least -3 and up to and including +3.

[0186] The topcoat composition can be disposed on the surface of the substrate in various ways using a number of application methods and means as described in greater detail below. For example, it can be disposed on the substrate as a continuously distributed layer, meaning that the layer is substantially uniform in terms of coating coverage, and no uncoated portions of the substrate surface are intended. Such a layer or coating can be applied using flexographic, gravure, or other known coating techniques and devices known in the coating art.

[0187] Alternatively, the topcoat composition can be disposed on the surface of the substrate as a pattern (as a regular (predetermined) pattern or an irregular pattern), which can be provided using, for example, a flexographic and appropriately patterned flexographic printing sleeve or a gravure and appropriately engraved gravure cylinder.

[0188] For all of the inkjet recording media embodiments according to the present application, the topcoat composition, once dried (i.e., less than 10 wt% or even less than 5 wt% of the aqueous medium remains), generally has a dry solid coating weight (or coating coverage) of at least 0.1 g / m2 2 or at least 0.2 g / m2 2 and up to and including 1 g / m2or up to and including 2 g / m2 2 or up to and including 10 g / m2 2 .

[0189] The necessary (a) water-soluble salt of one or more polyvalent metal cations (as described above) is typically present in the topcoat composition in an amount of at least 0.4 wt% or at least 15 wt% and up to and including 40 wt%, based on the total weight of the topcoat composition. Generally, useful coverage of the topcoat composition will provide at least 1.2 wt% and up to and including 40 wt% of the polyvalent metal cations, based on the total weight of the topcoat composition.

[0190] For example, the (a) water-soluble salt of one or more polyvalent metal cations can be present in an amount sufficient to provide at least 0.01 g / m 2 and up to and including 4 g / m 2 of the polyvalent cations (e.g., calcium cations) in the topcoat composition.

[0191] Additionally, the necessary (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder materials (as described above) can be present in the topcoat composition in an amount of at least 0.5 wt% or at least 2 wt% and up to and including 30 wt% or up to and including 90 wt%, based on the total weight of the topcoat composition.

[0192] The necessary (c) surface-treated, visible light-scattering particles (as described above) are present in the topcoat composition in an amount of at least 6 wt% and up to and including 50 wt% or up to and including 90 wt%, based on the total weight of the topcoat composition. Particularly useful (c) surface-treated, visible light-scattering particles include surface-treated, visible light-scattering titanium dioxide particles, such as alumina-treated, visible light-scattering titanium dioxide particles.

[0193] The (d) particles (as described above) different from the necessary (c) component having a Rockwell hardness of less than or equal to R90 (or D75) can be present in the topcoat composition in an amount of at least 0.06 wt% or at least 0.5 wt% and up to and including 5 wt% or up to and including 10 wt%, based on the total weight of the topcoat composition. In some embodiments, the (d) particles can have an ESD that is at least 0.1 pm greater than the sum of the dry thickness of the topcoat composition and the dry thickness of any inkjet-printed image or layer.

[0194] Additionally, the (e) cross-linkable polymeric material (as described above) that is also different from all of the (a), (b), (c), and (d) components can be present in the topcoat composition in an amount of at least 0.1 wt% and up to and including 20 wt% or up to and including 30 wt%, based on the total weight of the topcoat composition. A cross-linking agent (as described above) can also be present, and useful amounts of such (e) cross-linking agents will readily be apparent to one of skill in the art using routine experimentation.

[0195] Additionally, as described above, (f) a dispersion aid for (c) the surface-treated, visible light-scattering particles (as described above) is cationic on a cumulative charge basis. Generally, (f) the dispersion aid is different from (a) the water-soluble salt of one or more polyvalent metal cations, and can be the same as or different from (b) the one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder materials. Such (f) dispersion aid can be present in the topcoat composition in an amount of at least 0.2 wt% and up to and including 50 wt%, based on the total weight of (c) the surface-treated, visible light-scattering particles. For example, a useful (f) dispersion aid can be a polymer having protonated nitrogen atoms, such as a protonated polyvinylamine or a protonated polyvinyl imidazole, or a copolymer derived at least in part from vinyl amine and vinyl alcohol, which can be present in an amount of at least 0.2 wt% and up to and including 50 wt%, based on the total weight of the surface-treated, visible light-scattering particles (which can be surface-treated, visible light-scattering titanium dioxide particles). Such (f) dispersion aid can be used, for example, when (b) the one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder materials includes at least a polyvinyl amine, a polyvinyl alcohol, a protonated polyvinyl imidazole, a protonated polyvinyl amine, or a copolymer derived at least in part from vinyl amine.

[0196] The resulting inkjet recording media can be used for various purposes, but it is particularly useful for inkjet printing processes to provide a monochromatic or multicolor (or multi-color) image or layer in an inkjet printed article. Such inkjet printed articles can then have a substrate and a topcoat composition, for example, as exemplified in each of Figure 1 and 2 with a water-based inkjet printed image or layer disposed over (e.g., directly on) the topcoat composition.

[0197] As described in more detail below, an inkjet printed image or layer can be formed by inkjet printing one or more of the water-based inkjet ink compositions described below.

[0198] Method for making an inkjet receiving medium

[0199] The aqueous composition according to the present application (also identified herein as a "topcoat composition formulation") can be used to make or form a topcoat composition having a desired opacity on only one or both opposing sides (or surfaces) of a substrate (as described above). Thus, a substrate is selected, and the aqueous composition according to the present application is formulated and disposed on at least one surface of the substrate and dried to provide a topcoat composition. The result of these operations is an inkjet receiving medium according to the present application that is useful for inkjet printing according to the present application.

[0200] The procedures and devices for accomplishing these operations can be selected from a variety of known techniques and devices, including but not limited to spray coating, bar coating, blade coating, gravure coating (direct, reverse or offset), flexographic coating, size press (mixing and metering) (coating), extrusion hopper coating, and curtain coating, using suitable equipment for these purposes.

[0201] In some embodiments, the topcoat composition can be disposed on the substrate surface in-line as part of the manufacture of the substrate (e.g., a papermaking process or a film forming process). Alternatively, the topcoat composition can be disposed on the substrate surface in a separate step after the substrate has been manufactured. Further, the topcoat composition can be formed in-line as part of a inkjet printing operation, where the aqueous composition is disposed on the substrate surface in a "pre-coat" or "pre-treatment" station prior to printing of the aqueous pigment-based ink using a multi-station device. Such pre-coat operations can be designed to provide uniform (continuous) coverage of the topcoat composition, or in some cases, the aqueous composition can be provided to only specific areas of the substrate to form a pattern or image. While the disposed topcoat composition can be dried completely prior to inkjet image printing, it can not be necessary to dry completely, and the overall drying of both the disposed topcoat composition and the inkjet printed image or layer can be performed simultaneously. The topcoat composition can be disposed on the substrate surface in a manner to provide a continuous distribution layer. For example, the aqueous composition can be disposed in a pattern using various application techniques such as gravure coating or flexographic printing, followed by inkjet printing in registration with the pattern.

[0202] Method and apparatus for inkjet printing

[0203] The inkjet receptive media according to the present application can be inkjet printed with one or more aqueous pigment-based inks containing one or more pigment colorants to provide a pigment-based image or layer. These aqueous pigment-based inks can be printed onto the topcoat composition of the inkjet receptive media designed and prepared as described above. The inkjet printing method according to the present application can be used to print periodicals, newspapers, magazines, greeting cards, lottery tickets, plastic packaging, paperboard, advertising, flexible packaging, labels, and other materials that will be readily apparent to those skilled in the art.

[0204] While the aqueous compositions according to the present application can be useful for inkjet receptive media useful in one or more drop-on-demand (DOD) printing systems, the advantages of the present application are particularly evident when using continuous inkjet (CIJ) printing processes and equipment to carry out the methods according to the present application at high printing speeds. There are several CIJ printing processes known in the art, and the present application is not limited to a particular CIJ process, but there can be certain CIJ processes that are more useful than others. Generally speaking, such CIJ processes use one or more aqueous pigment-based inks that are jetted through one or more printheads (containing nozzles), and the unprinted aqueous pigment-based ink is collected and recirculated through the printing system multiple times until it is used up. In addition, CIJ printing systems can have a replenishment system incorporated. Details of such CIJ processes and equipment are provided, for example, in U.S. Patent 8,173,215 (Sowinski et al.).

[0205] Thus, in most CIJ inkjet printing processes, each aqueous pigment-based ink can be jetted or printed only from a main fluid supply dedicated thereto as a continuous stream of aqueous pigment-based ink that is split into both printed and non-printed drops. The non-printed drops of each aqueous pigment-based ink can be collected using a suitable collection device, such as a "catcher," and returned to its respective main fluid supply. This entire scheme can be carried out using a single (first) aqueous pigment-based ink alone or using a combination of the first aqueous pigment-based ink with one or more "additional" aqueous pigment-based inks having the same or different "colors" or shades as the first aqueous pigment-based ink. The multiple aqueous pigment-based inks are then jet printed in a controlled manner in a selected order that can be controlled by software and digital input to provide a multicolor inkjet printed image on the surface of the inkjet receptive media.

[0206] The one or more aqueous pigment-based inks can each be supplied from a respective main fluid supply as one or more continuous streams, and these one or more continuous streams can each be split into both printed and non-printed drops, the non-printed drops are collected, and returned from each of the one or more continuous streams to the respective main fluid supply.

[0207] In addition, inkjet printing of aqueous "colorless" or aqueous pigment-free ink compositions or fluids can be carried out instead of, simultaneously with, or sequentially to inkjet printing of colored aqueous pigment-based inks. For example, according to U.S. Patent Application Publication 2018 / 0051184 (Lussier et al.), a colorless paint or ink composition can be applied over a monochromatic or multichromatic pigment-based image or layer. The inkjet receptive media according to the present application can be used in such printing processes.

[0208] Printing press replenishment systems for maintaining the quality of aqueous pigment-based inks and to counteract the effects of volatile component evaporation and to measure ink resistivity are described, for example, in U.S. Patent 5,526,026 (Bowers) and EP 0597628B1 (Loyd et al.). Useful CIJ printing processes and apparatus employing other means for aqueous pigment-based ink concentration sensing are disclosed in U.S. Patent 7,221,440 (McCann et al.) and EP 0 571,784B1 (McCann et al.) and EP 1,013,450B1 (Woolard et al.).

[0209] In one embodiment, replenishment is carried out as follows: the fluid system contains an ink resistivity measurement unit through which the aqueous pigment-based ink passes as it is recirculated through the ink handling portion of the system, including the print head. A computing device determines the resistance of the ink resistivity unit. A logic and control unit responsive to the computing device controls the transfer of aqueous pigment-based ink from a replenishment "ink" supply and the transfer of aqueous particulate-free fluid ("carrier liquid") from a replenishment carrier liquid supply to the system main fluid supply to maintain the desired resistivity in the aqueous inkjet ink composition. The volume of aqueous pigment-based ink is monitored by the float valve position, and when a predetermined volume has been depleted, the predetermined volume is replaced by aqueous pigment-based ink from the replenishment "ink" supply or carrier liquid from the replenishment carrier liquid supply. Thus, the first aqueous pigment-based ink and any additional aqueous pigment-based ink can be replenished with the first aqueous pigment-based ink and any additional aqueous pigment-based ink, respectively.

[0210] In other examples, the method according to the present application can further comprise replenishing the main fluid supply with an aqueous particulate-free fluid having a dynamic viscosity of less than or equal to 5 centipoise (5 mPa.s) at 25 °C as measured using a rolling ball viscometer.

[0211] In some embodiments, the method according to the present application is performed using a plurality of printed drops formed from a continuous fluid stream, and non-printed drops of different volume than the printed drops are diverted by the droplet deflection device into a "catcher" for collection and recycling. Details regarding such CIJ printing systems and apparatus are provided in, for example, U.S. Patents 6,588,888 (Jeanmaire et al.), 6,554,410 (Jeanmaire et al.), 6,682,182 (Jeanmaire et al.), 6,793,328 (Jeanmaire et al.), 6,866,370 (Jeanmaire et al.), 6,575,566 (Jeanmaire et al.), and 6,517,197 (Hawkins et al.), as well as U.S. Patent Application Publication 2002 / 0202054 (Jeanmaire et al.).

[0212] In other embodiments, aqueous pigment-based inks can be printed using apparatus capable of controlling the direction of printed and non-printed drops formed by asymmetrically applying heat to a fluid stream, which initiates droplet breakup and is used to direct the resulting droplets, as described in, for example, U.S. Patents 6,079,821 (Chwalek et al.) and 6,505,921 (Chwalek). Useful agitation, heated supply, printhead, and fluid filtration devices for CIJ printing are described in, for example, U.S. Patent 6,817,705 (Crockett et al.).

[0213] A simple schematic of a CIJ printing system is provided in Figure 1 U.S. Patent 8,764,161 (Cook et al.). Other useful details regarding CIJ printing apparatus and printhead manufacture are described in, for example, U.S. Patent 6,943,037 (Anagnostopoulos et al.).

[0214] Accordingly, the printing method according to the present application can be performed using a continuous high-speed commercial inkjet printer, such as in which the inkjet printer uses one or more different printheads (e.g., full-width printheads relative to the inkjet receiving medium) to sequentially apply colored images, in which different colored portions of the image are to be registered.

[0215] One type of continuous inkjet (CIJ) printing uses a pressurized ink source that produces a continuous stream of printing droplets (small droplets) from a main fluid supply for each aqueous pigment-based ink, or produces a continuous stream that is split into both printing and non-printing droplets. Continuous inkjet printers can utilize an electrostatic charging device that is placed close to the site where the filament of working inkjet composition is split into charged single droplets, and then directed to the appropriate location by a deflection electrode with a large potential difference. In cases where a color image is not required, the non-printing droplets can be deflected into an ink capture mechanism and disposed of or recycled by returning them to the original main fluid supply. When a color image is required to be printed, the printing droplets are not deflected, but are allowed to impact the topcoat composition of the inkjet receiving medium at the designated location. Alternatively, the deflected printing droplets can be allowed to impact the topcoat composition of the inkjet receiving medium, while the non-deflected non-printing droplets can be collected and returned to the main fluid supply.

[0216] In some embodiments, the method according to the present application can include printing one or more aqueous pigment-based inks onto a topcoat composition of an inkjet receiving medium using an inkjet deposition system responsive to an electrical signal to provide a pigment-based image in a predetermined pattern, and the predetermined pattern can be inkjet printed in a manner that is registered with the same pattern provided by the topcoat composition.

[0217] Thus, printing one or more aqueous pigment-based inks onto a topcoat composition disposed as a pattern on a surface of a substrate in a manner to provide a pigment-based image registered with the pattern of the topcoat composition can be achieved using a suitable inkjet deposition system.

[0218] For example, the topcoat composition can be disposed on a surface of a substrate in a pattern using flexographic printing, and B) inkjet printing one or more aqueous pigment-based inks onto the pattern of the topcoat composition to provide a pigment-based image registered with the pattern of the topcoat composition can be performed in-line at different stations of a multi-station apparatus.

[0219] In such embodiments, the substrate can comprise a hydrophobic surface prior to the topcoat composition being formed thereon that is impervious to water or the aqueous ink composition, and wherein the topcoat composition provides a hydrophilic surface relative to the hydrophobic surface of the substrate.

[0220] Such substrates can comprise a transparent, translucent, or metallized polymeric film, or a co-extrudate or laminate of two or more transparent, translucent, or metallized polymeric films.

[0221] Aqueous pigment-based inks useful according to the present application can be prepared from a suitable aqueous dispersion of one or more particulate pigments using known dispersing agents and dispersing devices. The resulting aqueous pigment-based inks can be mixed with one or more humectants or co-solvents, and the components can be formulated in an aqueous medium (primarily water) to provide an aqueous pigment-based inkjet ink having a dynamic viscosity of less than or equal to 10 centipoise (10 mPa.s), or less than or equal to 5 centipoise (3 mPa.s), or even less than or equal to 3 centipoise (1.5 mPa.s), all as described above, measured at 25 °C.

[0222] Each aqueous pigment-based ink useful in the practice of the present application generally includes one or more particulate organic or inorganic pigment colorants that will provide the desired color or shade, such as black, green, red, yellow, blue, violet, magenta, cyan, white, brown, gray, and other shades known in the art. The pigment colorants can be present individually or in mixtures in each aqueous pigment-based ink. For example, an aqueous pigment-based ink useful in the present application includes one or more pigment colorants selected from the group consisting of cyan pigments, magenta pigments, yellow pigments, black pigments, green pigments, orange pigments, white pigments, red pigments, blue pigments, violet pigments, and combinations of any of these pigment colorants, and any or all of these pigments can be anionically stabilized as described below.

[0223] A wide variety of organic and inorganic pigment colorants can be used, either individually or in combination. For example, carbon black pigments can be combined with colored pigments, such as cyan copper phthalocyanine or magenta quinacridone pigments. Useful pigments are described in, for example, U.S. Patents 5,026,427 (Mitchell et al.), 5,141,556 (Matrick), 5,160,370 (Suga et al.), and 5,169,436 (Matrick).

[0224] Specific useful pigment colorants are described in U.S. Patent 8,455,570 (Lindstrom et al.) at column 10 (line 66) to column 11 (line 40). Mixtures of pigments can be used to provide a desired shade or color, as described, for example, in U.S. Patent 9,605,169 (Lussier et al.).

[0225] Useful pigment colorants can be accompanied by a suitable polymeric or non-polymeric dispersant as is well known in the art (as described above), or the pigment colorants can be self-dispersing and thus dispersible and stable in the aqueous pigment-based ink without the use of a dispersant due to the presence of appropriate surface groups. Examples of useful self-dispersing pigment colorants are described in column 11 (lines 49-53) of U.S. Patent 8,455,570 (referenced above).

[0226] Particularly useful, the pigment colorants used in the present invention are stabilized by anionic moieties (i.e., “anionically stabilized pigments”). Such pigment colorants are commercially available from various commercial sources, and the skilled artisan will know what types of pigment colorants can be used in the present invention. For example, some such pigment colorants are self-dispersing pigments that are dispersible and stable without the use of a polymeric or molecular dispersant or surfactant.

[0227] Useful pigment colorants can have a median particle size of less than 150 nm, and more likely less than 100 nm or even less than 50 nm. The term “median particle size” as used herein refers to the D 50 of the particle size distribution such that 50% of the volume of the pigment colorant particles are provided by particles having a diameter less than the indicated diameter. Particle size distribution can be measured using a laser light scattering device as described above.

[0228] The organic or inorganic pigment colorants can be present in each aqueous pigment-based ink in an amount of at least 0.1 wt% and up to and including 30 wt%, or more likely at least 1 wt% and up to and including 10 wt%, or even at least 1 wt% and up to and including 8 wt%, based on the total weight of the aqueous pigment-based ink.

[0229] Each aqueous pigment-based ink typically includes one or more humectants, which are typically water-soluble or water-miscible organic solvents having a viscosity greater than 40 centipoise (0.040 mPa.s) or even at least 100 centipoise (0.1 mPa.s) when measured at 25°C. For example, any water-soluble humectant known in the inkjet art that is compatible with the other requirements of the present invention can be used. While a single humectant can be employed, a mixture of two or more humectants (each imparting useful properties) can be used. Representative humectants are described, for example, in U.S. Patent 9,783,553 (Lussier et al.).

[0230] The one or more humectants (e.g., triethylene glycol) can be present in an amount of at least 0.5 wt% or at least 1 wt% and up to and including 10 wt%, or at least 3 wt% and up to and including 7 wt%, all based on the total weight of the aqueous pigment-based ink.

[0231] Each aqueous pigment-based ink useful according to the present application can further comprise one or more anionic polyurethanes each having an acid value of at least 50 or at least 60 and up to and including 150, or even at least 55 and up to and including 90, which materials are described in more detail below.

[0232] Alternatively, or in addition to anionic polyurethanes, the aqueous pigment-based ink can comprise one or more anionic (meth)acrylic or anionic styrene-(meth)acrylic polymers each having an acid value of at least 50 or at least 120 and up to and including 240, or even at least 160 and up to and including 220, which polymers are described in more detail below. The term (meth)acrylic refers to both acrylic and methacrylic materials.

[0233] Representative examples of both types of polymers are described, for example, in U.S. Patents 8,430,492 (Falkner et al.) and 9,783,553 (referenced above). For example, particularly useful polyether polyurethanes are each represented by Structure (I) in U.S. Patent 9,783,553 (referenced above).

[0234] Useful water-soluble or water-dispersible anionic polyether polyurethanes can be prepared as described, for example, in

[0045] -

[0049] of U.S. Patent Application Publication 2008 / 0207811 (Brust et al.). The acidic groups in the anionic polyether polyurethanes can be at least partially and up to 100% neutralized (converted to salts) using a monovalent inorganic base (e.g., an alkali metal hydroxide) or an organic amine (e.g., dimethyl ethanolamine).

[0235] Representative anionic (meth)acrylic and anionic styrene-(meth)acrylic polymers useful in the present application are described, for example, in

[0061] of U.S. Patent Application Publication 2008 / 207811 (referenced above). Examples of useful anionic styrene-acrylic polymers include those marketed under the trademarks SILQUEST® A-2080 (S.C. Johnson Co.), SILQUEST® A-2080 (S.C. Johnson Co.), SILQUEST® A-2080 (S.C. Johnson Co.).

[0236] In addition, modified polysiloxanes can be present in the aqueous pigment-based ink. Examples of such materials are "surface active agents" based on ethoxylated or propoxylated silicones, which are marketed under the trademarks SILQUEST® A-2080 (S.C. Johnson Co.), SILQUEST® A-2080 (S.C. Johnson Co.), 348 and 381) and Dow Corning DC67, DC57, DC28, DC500W, and DC51 are commercially available. Non-silicone surfactants can also be used, including but not limited to anionic surfactants, cationic surfactants, non-ionic surfactants, or amphoteric surfactants, such as those available as Air Products) including 440 and 465 acetylenic diol surfactants.

[0237] Colorless fluorescent colorants (dyes or pigments) can also be present in the aqueous pigment-based inks, and examples of such compounds are described in U.S. Patent Application Publication 2014 / 231674 (Cook).

[0238] Other additives (the amounts of which will readily be apparent to one skilled in the art) that can be present in the aqueous pigment-based inks include, but are not limited to, co-solvents, thickening agents, conductivity enhancers, drying agents, water resistance agents, viscosity modifiers, pH buffers, preservatives, antifoams, wetting agents, corrosion inhibitors, biocides, fungicides, antifoams (such as DF110L, PC, MD-20, and DF-70), UV radiation absorbers, antioxidants and light stabilizers (available under the trademarks (Ciba) and (Ciba) and other additives described in column 17 (lines 11-36) of U.S. Patent 8,455,570 (referenced above).

[0239] Water is typically present in each aqueous pigment-based ink in an amount of at least 75 wt% or at least 80 wt%, and typically no more than 90 wt%, based on the total weight of the aqueous pigment-based ink.

[0240] The pH of each aqueous pigment-based ink can be adjusted, if desired, to be at least 8 and up to and including 12, or more likely at least 8 and up to and including 10, or in some embodiments at least 8 and up to and including 9.5.

[0241] The various aqueous pigment-based inks useful according to the present application can be supplied individually or as components of an ink set, which can be designed for use in the same inkjet printing device.

[0242] Inkjet printed articles

[0243] An inkjet printed article prepared according to the present application comprises a substrate (as described above) on which has been disposed a topcoat composition (as described above), and on which has been disposed at least one water-based inkjet printed image or layer by inkjet printing. As mentioned above, such inkjet printed image or layer can be monochromatic (single color) or multichromatic, or even colorless, or a colorless image or layer can be formed on a monochromatic or multichromatic inkjet printed image.

[0244] In some embodiments (e.g., as exemplified in Figure 3 In some embodiments (e.g., as exemplified in

[0245] Some methods of the present application can include, after B) inkjet printing one or more aqueous pigment-based inks on the topcoat composition:

[0246] C) applying an aqueous colorless ink composition as known in the art to the pigment-based image or layer.

[0247] The resulting inkjet printed article according to the present application can have a topcoat composition disposed as a pattern or layer on the surface of the substrate, and a pigment-based inkjet printed pattern (or image) that can be arranged in register with the pattern or layer of the topcoat composition. Additionally, an aqueous colorless ink composition can be disposed as a pattern in register with the pigment-based inkjet printed pattern or image in that particular inkjet printed article.

[0248] A clear protective layer can be used as a post-print functional layer to protect the inkjet printed article against environmental and physical damage and stress, providing abrasion resistance, fingerprint resistance, and delamination resistance. Such a clear protective layer can be provided as described in U.S. Patent Application Publication 2018 / 0051184 (mentioned above). Additionally, known water-based overprint varnishes such as Haut Brilliant 17-604327-7 (Siegwerk) and Micheal Huber Munchen 877801 Varnish Anticurling can be applied as a clear post-print functional layer.

[0249] An adhesive layer can be present as a post-print functional layer to provide adhesion, particularly in applications such as flexible laminated packaging where it is desirable to bond separate film or paper layers to treated, coated or printed layers. Useful examples of water-based adhesives for such adhesive layers include, but are not limited to, Dow Chemical ROBOND TM Acrylic adhesives L90M, L148 and L330. Another option is Dow Chemical AQUALAM TM Polyurethane water-based adhesives.

[0250] Reference is made to Figure 3 When a post-print functional layer 350 is present and is water-based, it can be applied or formed using any of the methods described above for applying or forming the first layer 320 and topcoat composition 330, including known coating and digital deposition processes. For example, the post-print functional layer 350 can be applied as a flood coating over the entire surface of the treated, coated and inkjet printed article, or the post-print functional layer 350 can be applied in a pattern-wise or image-wise manner. If the post-print functional layer 350 is free of solvent, a melt extrusion process can be used to apply the post-print functional layer 350, in which a molten or viscous solvent-free composition is extruded as a continuous layer over the surface of the dried water-based inkjet printed image or layer 340. Following extrusion, the post-print functional layer 350 can be further processed using heat and pressure to improve adhesion, followed by cooling. In some embodiments, the solvent-free composition can be a two-part reactive composition intended to act as an adhesive, using heat or pressure to laminate a continuous protective post-print functional layer thereon.

[0251] In some other embodiments, the inkjet printed article according to the present application is simpler in structure (not shown) than that exemplified in Figure 3 In such embodiments, the water-based inkjet printed image or layer 340 is disposed directly on the topcoat composition. Thus, the first layer 320 is omitted. A post-print functional layer 350 can be present in or omitted from such embodiments.

[0252] Other useful embodiments of the inkjet receiving medium and resulting inkjet printed article can be envisioned by the skilled artisan using the present teachings.

[0253] The present application provides at least the following embodiments and combinations thereof, although as the skilled artisan will appreciate from the teachings of the present disclosure, other combinations of features are considered within the present application:

[0254] 1. An aqueous composition for pretreating a substrate prior to inkjet printing on the substrate, the aqueous composition having at least 2 percent solids and up to and including 90 percent solids, and the aqueous composition comprising the following (a), (b), and (c) components:

[0255] (a) water soluble salts of one or more polyvalent metal cations, the (a) one or more water soluble salts being present in an amount of at least 0.5 weight percent and up to and including 30 weight percent;

[0256] (b) one or more non-ionic or cationic water soluble or water dispersible polymeric binder materials, present in an amount of at least 0.1 weight percent and up to and including 30 weight percent; and

[0257] (c) visible light scattering particles that have been surface treated such that the aqueous composition has a stable zeta potential greater than +4 millivolts, and the (c) surface treated visible light scattering particles being present in an amount of at least 5 weight percent and up to and including 60 weight percent,

[0258] wherein the amounts of the (a), (b), and (c) components are based on the total weight of the aqueous composition.

[0259] 2. The aqueous composition of embodiment 1, wherein the (c) surface treated visible light scattering particles exhibit a D 50 (median) particle size of at least 0.04 μm and up to and including 2 μm, as measured by a particle analyzer that provides a volume weighted particle size distribution.

[0260] 3. The aqueous composition of embodiment 1 or 2, wherein the (c) surface treated visible light scattering particles exhibit a D 50 (median) particle size of at least 0.04 μm and up to and including 0.5 μm, as measured by a particle analyzer that provides a volume weighted particle size distribution.

[0261] 4. The aqueous composition of any of embodiments 1-3, further comprising:

[0262] (d) particles different from the (c) component, the (d) particles having a Rockwell hardness less than or equal to R90, and present in an amount of at least 0.02 weight percent and up to and including 5 weight percent, based on the total weight of the aqueous composition.

[0263] 5. The aqueous composition of any of embodiments 1-4, further comprising:

[0264] (e) a cross-linkable polymeric material that is different from all of (a), (b), (c), and (d), and present in an amount of at least 0.1 wt% and up to and including 30 wt%, based on the total weight of the aqueous composition.

[0265] 6. The aqueous composition of any of embodiments 1-5, further comprising:

[0266] (f) a dispersion aid for the (c) surface-treated, visible light-scattering particles, the (f) dispersion aid being cationic on a cumulative charge basis, and present in an amount of at least 0.2 wt% and up to and including 50 wt%, based on the total weight of the (c) surface-treated, visible light-scattering particles.

[0267] 7. The aqueous composition of embodiment 6, wherein the (f) dispersion aid is a polymer having at least one protonated nitrogen atom, and present in the aqueous composition in an amount of at least 1 wt% and up to and including 20 wt%, based on the total weight of the (c) surface-treated, visible light-scattering particles.

[0268] 8. The aqueous composition of any of embodiments 1-7, wherein the (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder material comprises one or more of: polyvinyl alcohol, polyethyleneimine, polyethylene oxide, polyvinylamine, a copolymer derived at least in part from ethylene alcohol and ethylene oxide, a copolymer derived at least in part from ethylene amine and ethylene alcohol, or a combination of two or more of these polymeric materials.

[0269] 9. The aqueous composition of any of embodiments 1-8, wherein the (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder material comprises at least polyvinylamine, polyethyleneimine, polyvinyl alcohol, a copolymer derived at least in part from ethylene amine and ethylene alcohol, or a combination of two or more of these polymeric materials.

[0270] 10. The aqueous composition of any of embodiments 7-9, wherein the (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder material is the same as the (f) dispersion aid.

[0271] 11. The aqueous composition of any of embodiments 1-10, having a dynamic viscosity of less than 2000 centipoise (2000 mPa.s) at 25°C as measured using a Brookfield Spindle Viscometer.

[0272] 12. The aqueous composition of any of embodiments 1-11, having a dynamic viscosity of at least 30 centipoise (30 mPa.s) and up to and including 800 centipoise (800 mPa.s), as measured using a Brookfield spindle viscometer at 25 °C.

[0273] 13. The aqueous composition of any of embodiments 1-12, wherein (a) the water soluble salt of one or more polyvalent metal cation is one or more water soluble salt of magnesium (+2), calcium (+2), barium (+2), zinc (+2), and aluminum (+3).

[0274] 14. The aqueous composition of any of embodiments 1-13, further comprising one or more of each of the following: a surfactant, an anti-corrosion compound, a biocide, a preservative, an antifoam agent, or a combination of two or more of these materials.

[0275] 15. The aqueous composition of any of embodiments 1-14, wherein (c) the surface treated, visible light scattering particles comprise silica, zinc oxide, titanium dioxide, zirconium oxide, aluminum oxide, barium sulfate, magnesium oxide, or a combination of two or more of these materials.

[0276] 16. The aqueous composition of any of embodiments 1-15, wherein (c) the surface treated, visible light scattering particles comprise surface treated, visible light scattering titanium dioxide particles.

[0277] 17. The aqueous composition of any of embodiments 1-16, comprising an aqueous medium containing at least 50 wt.% water, based on the total weight of all solvents in the aqueous medium.

[0278] 18. An aqueous composition of one or more embodiments of the present invention to provide for pretreatment of a substrate prior to inkjet printing on the substrate, the aqueous composition having at least 5% solids and up to and including 70% solids, and having a dynamic viscosity of at least 30 centipoise (30 mPa.s) and up to and including 800 centipoise (800 mPa.s), as measured using a Brookfield spindle viscometer at 25 °C, and

[0279] the aqueous composition comprising the following (a), (b), (c), (d), (e), and (f) components:

[0280] (a) one or more water soluble salt of magnesium (+2), calcium (+2), barium (+2), or mixtures thereof, said (a) one or more water soluble salt being present in an amount of at least 1 wt.% and up to and including 25 wt.%, based on the total weight of the aqueous composition;

[0281] (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder materials comprising at least polyvinyl alcohol, polyvinyl amine, polyethylene imine, a copolymer derived at least in part from ethylene amine and ethylene alcohol, or a combination of two or more of these polymeric materials, the (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder materials being present in an amount of at least 0.1 wt% and up to and including 30 wt%, based on the total weight of the aqueous composition;

[0282] (c) visibly scattering particles comprising visibly scattering titania particles that have been surface treated such that the aqueous composition has a stable zeta potential greater than +10 millivolts, wherein the surface treated visibly scattering titania particles exhibit a D 50 (mean) particle size of at least 0.04 μm and up to and including 2 μm, as measured using a particle size analyzer that provides a volume weighted particle size distribution, and the surface treated visibly scattering particles are present in an amount of at least 10 wt% and up to and including 40 wt%, based on the total weight of the aqueous composition;

[0283] (d) particles that are different from the (c) component, the (d) particles having a Rockwell hardness less than or equal to R75, and being present in an amount of at least 0.05 wt% and up to and including 3 wt%, based on the total weight of the aqueous composition;

[0284] (e) a cross-linkable polymeric material that is different from all of the (a), (b), (c), and (d) components, and the (e) cross-linkable polymeric material is present in an amount of at least 0.2 wt% and up to and including 8 wt%, based on the total weight of the aqueous composition; and

[0285] (f) a dispersing aid for the (c) surface treated visibly scattering titania particles, the (f) dispersing aid being a polymer having protonated nitrogen atoms, and being present in an amount of at least 0.2 wt% and up to and including 50 wt%, based on the total weight of the (c) surface treated visibly scattering titania particles.

[0286] 19. The aqueous composition of embodiment 18, wherein the (f) dispersing aid is at least a protonated polyethylene imine or a protonated polyvinyl amine.

[0287] 20. The aqueous composition of embodiment 18 or 19, wherein the (c) surface treated visibly scattering particles comprise surface treated visibly scattering titania particles.

[0288] 21. The aqueous composition of any of embodiments 18-20, comprising an aqueous medium containing at least 50 wt% water, based on the total weight of all solvents in the aqueous medium.

[0289] 22. An inkjet receiving medium comprising a substrate and a topcoat composition disposed on a surface of the substrate, the topcoat composition derived from the aqueous composition of any of embodiments 1-21 and comprising the following (a), (b), and (c) components:

[0290] (a) water-soluble salts of one or more polyvalent metal cations, the (a) one or more water-soluble salts being present in an amount of at least 0.4 wt% and up to and including 40 wt%;

[0291] (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder materials, present in an amount of at least 0.5 wt% and up to and including 90 wt%; and

[0292] (c) particles that scatter visible light, which have been surface treated, and which are present in an amount of at least 6 wt% and up to and including 90 wt%,

[0293] wherein the amounts of (a), (b), and (c) components are based on the total weight of the topcoat composition.

[0294] 23. The inkjet receiving medium of embodiment 22, wherein the topcoat composition has a dry solid coating weight of at least 0.1 g / m 2 and up to and including 10 g / m 2 .

[0295] 24. The inkjet receiving medium of embodiment 22 or 23, wherein the topcoat composition has a dry solid coating weight of at least 0.2 g / m 2 and up to and including 2 g / m 2 .

[0296] 25. The inkjet receiving medium of any of embodiments 22-24, wherein the topcoat composition has a dry solid coating weight of at least 0.2 g / m 2 and up to and including 1 g / m 2 .

[0297] 26. The inkjet receiving medium of any of embodiments 22-25, wherein the substrate is a transparent, translucent, or metallized polymeric film.

[0298] 27. The inkjet receiving medium of any of embodiments 22-26, wherein the substrate has an L* value of 50 or less.

[0299] 28. The inkjet receiving media of any of embodiments 22-27, wherein the topcoat composition has an opacity of at least 30% and a colorimetric hue defined by an a* value of at least -5 and at most and including +5 and a b* value of at least -5 and at most and including +5.

[0300] 29. The inkjet receiving media of any of embodiments 22-28, wherein the topcoat composition is disposed on the substrate surface as a continuous distribution.

[0301] 30. The inkjet receiving media of any of embodiments 22-28, wherein the topcoat composition is disposed on the substrate surface as a pattern.

[0302] 31. The inkjet receiving media of any of embodiments 22-30, wherein the substrate comprises a hydrophobic surface prior to the topcoat composition being disposed thereon, the hydrophobic surface is impervious to the aqueous pigment-based ink composition, and the topcoat composition provides a hydrophilic surface relative to the hydrophobic surface of the substrate.

[0303] 32. The inkjet receiving media of any of embodiments 22-30, wherein the substrate is capable of absorbing and transferring the aqueous pigment-based ink colorant into the interior of the substrate prior to the topcoat composition being disposed thereon.

[0304] 33. The inkjet receiving media of any of embodiments 22-30, wherein the substrate comprises a water-impermeable support and a first layer disposed on at least one surface of the water- impermeable support and underlying the topcoat composition.

[0305] 34. The inkjet receiving media of embodiment 33, wherein the water-impermeable support comprises a transparent or translucent polymeric film, or a co-extrudate or laminate of two or more transparent, translucent, or metallized polymeric films.

[0306] 35. The inkjet receiving media of any of embodiments 22-34, wherein the topcoat composition further comprises (d) a particulate different from the (c) component in an amount of at least 0.06 wt% and at most and including 10 wt% based on the total weight of the topcoat composition.

[0307] 36. The inkjet receiving media of any of embodiments 22-35, wherein the topcoat composition further comprises (e) a cross-linkable polymeric material different from all of (a), (b), and (c) components in an amount present of at least 0.1 wt% and at most and including 30 wt% based on the total weight of the topcoat composition.

[0308] 37. The inkjet receptive media of any of embodiments 22-36, further comprising (f) a dispersion aid for the (c) visible light scattering particles, the (f) dispersion aid being present in an amount of at least 0.2 wt% and up to and including 50 wt%, based on the total weight of the (c) surface treated visible light scattering particles.

[0309] 38. The inkjet receptive media of any of embodiments 22-37, wherein the substrate surface has a static surface energy of greater than 45 dynes / cm prior to disposing the topcoat composition.

[0310] 39. The inkjet receptive media of any of embodiments 22-38, wherein the (f) dispersion aid comprises at least a protonated polyethyleneimine or a protonated polyvinylamine.

[0311] 40. A method for providing the inkjet receptive media of any of embodiments 21-39, the method comprising, in order:

[0312] A) providing a substrate; and

[0313] B) disposing the aqueous composition of any of embodiments 1-20 onto at least one surface of the substrate to provide the inkjet receptive media having the topcoat composition on the at least one substrate surface.

[0314] 41. The method of embodiment 40, comprising disposing the topcoat composition on the substrate surface to provide a continuous distribution layer.

[0315] 42. The method of embodiment 40 or 41, comprising disposing the topcoat composition using gravure coating or flexographic printing.

[0316] 43. The method of embodiment 42, comprising disposing the topcoat composition as a pattern on the substrate surface.

[0317] 44. The method of any of embodiments 40-43, comprising disposing the aqueous composition on the substrate surface in-line after the substrate is prepared.

[0318] 45. The method of any embodiment of the present invention, including embodiments 40-44 mentioned above, wherein the substrate comprises a transparent, translucent, or metallized polymeric film, and the method comprises disposing the aqueous composition such that the resulting topcoat composition has a dry solids coating weight of at least 0.2 g / m 2 and up to and including 2 g / m 2 and the aqueous composition comprises the following (a), (b), (c), (d), (e), and (f) components:

[0319] (a) one or more water soluble salts of magnesium (+2), calcium (+2), barium (+2), or mixtures thereof, present in an amount of at least 1 wt% and up to and including 25 wt%, based on the total weight of the aqueous composition;

[0320] (b) one or more non-ionic or cationic water soluble or water dispersible polymeric binder materials comprising at least polyvinyl alcohol, polyvinyl amine, polyethylene imine, a copolymer derived at least in part from ethylene amine and ethylene alcohol, or a combination of two or more of these polymeric materials, present in an amount of at least 1 wt% and up to and including 8 wt%, based on the total weight of the aqueous composition;

[0321] (c) visible light scattering particles comprising titanium dioxide particles that scatter visible light, which have been surface treated such that the aqueous composition has a stable zeta potential greater than +10 millivolts, wherein the surface treated visible light scattering titanium dioxide particles exhibit a D 50 (median) particle size of at least 0.04 μm and up to and including 2 μm, as measured using a particle size analyzer that provides a volume weighted particle size distribution, and are present in an amount of at least 10 wt% and up to and including 40 wt%, based on the total weight of the aqueous composition;

[0322] (d) particles different from the (c) component, which (d) particles have a Rockwell hardness less than or equal to R75, and are present in an amount of at least 0.05 wt% and up to and including 3 wt%, based on the total weight of the aqueous composition;

[0323] (e) a cross-linkable polymeric material different from all of the (a), (b), (c), and (d) components, and present in an amount of at least 0.2 wt% and up to and including 8 wt%, based on the total weight of the aqueous composition; and

[0324] (f) a dispersion aid for the (c) surface treated visible light scattering titanium dioxide particles, which (f) dispersion aid is a polymer having protonated nitrogen atoms, and is present in an amount of at least 0.2 wt% and up to and including 50 wt%, based on the total weight of the (c) surface treated visible light scattering titanium dioxide particles.

[0325] 46. The method of embodiment 45, wherein the (f) dispersion aid comprises at least protonated polyethylene imine or protonated polyvinyl amine.

[0326] 47. A method for inkjet printing comprising in order:

[0327] A) providing the inkjet receptive media described in any of embodiments 22-39; and

[0328] B) inkjet printing one or more aqueous pigment-based inks onto the topcoat composition to provide a pigment-based image or layer.

[0329] 48. The method described in embodiment 47, wherein the one or more aqueous pigment-based inks comprise one or more pigment colorants selected from the group consisting of cyan pigments, magenta pigments, yellow pigments, black pigments, green pigments, orange pigments, white pigments, red pigments, blue pigments, violet pigments, or combinations of any of these pigment colorants.

[0330] 49. The method described in embodiment 47 or 48, wherein the one or more aqueous pigment-based inks independently comprise an anionic polyurethane, a humectant, an anionic (meth)acrylic polymer, an anionic styrene-(meth)acrylic polymer, or any combination of these materials.

[0331] 50. The method described in any of embodiments 47-49, further comprising:

[0332] C) applying an aqueous colorless ink composition to the pigment-based image or layer.

[0333] 51. The method described in any of embodiments 47-50, comprising printing the one or more aqueous pigment-based inks onto the topcoat composition disposed as a pattern on the surface of the substrate using an inkjet deposition system to provide a pigment-based image that is registered with the pattern of the topcoat composition.

[0334] 52. The method described in any of embodiments 47-51, wherein each of the one or more aqueous pigment-based inks is supplied as one or more continuous streams from a respective main fluid supply, each of the one or more continuous streams being split into both printing drops and non-printing drops; and

[0335] collecting the non-printing drops from each of the one or more continuous streams and returning them to the respective main fluid supply.

[0336] 53. The method described in any of embodiments 47-52, wherein each of the one or more aqueous pigment-based inks has a viscosity of less than or equal to 5 centipoise (5 mPa.s) as measured at 25°C using a rolling ball viscometer.

[0337] 54. The method of any of embodiments 47-53, comprising disposing the overcoat composition on the substrate surface in a pattern using flexographic printing, and B) inkjet printing one or more aqueous pigment-based inks onto the pattern of overcoat composition to provide a pigment-based image in register with the pattern of overcoat composition.

[0338] 55. The method of any of embodiments 47-54, comprising disposing the overcoat composition on the substrate surface, and conducting B) inkjet printing in-line at different stations of a multi-station apparatus.

[0339] 56. A method for providing an inkjet printed article, comprising in order:

[0340] A’) providing a substrate having a surface,

[0341] A”) providing an inkjet receptive medium by disposing the aqueous composition of any of embodiments 1-20 onto the surface of the substrate to form an overcoat composition; and

[0342] B) inkjet printing one or more aqueous pigment-based inks onto the overcoat composition to provide a pigment-based image or layer.

[0343] 57. An inkjet printed article, comprising:

[0344] a substrate comprising a surface;

[0345] an overcoat composition disposed on the surface of the substrate, the overcoat composition being derived from the aqueous composition of any of embodiments 1-20, and the overcoat composition comprising the following (a), (b), and (c) components:

[0346] (a) water-soluble salts of one or more polyvalent metal cations, the (a) one or more water-soluble salts being present in an amount of at least 0.4 wt% and up to and including 40 wt%;

[0347] (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder materials, present in an amount of at least 2 wt% and up to and including 90 wt%; and

[0348] (c) visible light-scattering particles that have been surface-treated, and present in an amount of at least 6 wt% and up to and including 90 wt%,

[0349] wherein the amounts of (a), (b), and (c) components are based on the total weight of the overcoat composition; and

[0350] a pigment-based inkjet printed layer or pattern disposed over the overcoat composition.

[0351] 58. The inkjet printed article of embodiment 57, wherein the overcoat composition has a dry solids coating weight of at least 0.1 g / m2 2 and up to and including 10 g / m2 2 .

[0352] 59. The inkjet printed article of embodiment 57 or 58, wherein the overcoat composition is disposed on the substrate surface as a pattern, and

[0353] the pigment-based inkjet printed pattern is arranged in registration with the pattern of the overcoat composition.

[0354] 60. The inkjet printed article of any of embodiments 57-59, wherein

[0355] a water-based colorless ink composition is disposed on the pigment-based inkjet printed layer or pattern.

[0356] The following examples are provided to illustrate the practice of the application and are not meant to be limiting in any way. Materials for which no specific commercial source is described are available from a variety of commercial sources that will be readily apparent to one skilled in the art.

[0357] In the following examples, the zeta potential of the aqueous compositions was measured using a Malvern Zetasizer Nano-ZS (zEN) instrument and the electrophoretic mobility of the test particles. Samples of the aqueous compositions were analyzed in undiluted state. The zeta potential was measured using a measurement technique, a combination of electrophoresis and laser Doppler velocity measurement, sometimes referred to as laser Doppler electrophoresis. This method measures how fast the particles move in a liquid when an electric field is applied, i.e., their velocity.

[0358] Particle size distributions were also obtained using a Horiba LA-920 instrument, utilizing static light technology to produce a volume weighted particle size distribution. In this procedure, each sample of particles was diluted with ultrapure water to produce an appropriate amount of light scattering within the limits exhibited by the instrument indicator. Each sample was analyzed with low level ultrasonics within the instrument to minimize any aggregation that can be present. Results are typically reported as either the average particle size or the median particle size, where the particle size is defined in terms of the equivalent spherical diameter (or ESD).

[0359] All of the examples described below that are labeled with an "I" are inventive examples, while the examples labeled with a "C" are comparative examples (outside of the invention).

[0360] Example 1

[0361] A 40 wt% dispersion of titanium dioxide (Ti02) was prepared in water using various (b) non-ionic or cationic water-soluble or water-dispersible polymeric binder materials as dispersants (hereinafter "polymer"). In a glass container, each polymer was added to water at the levels indicated in Table I below and stirred until dissolved. If the rate of dissolution was too slow, the temperature of the resulting solution was increased. To each polymer solution, Chemours R-960 Ti02scatterable visible light particles in powder form were slowly added until the powder was wetted to provide the requisite (c) surface-treated scatterable visible light particles. The resulting dispersion was then stirred with a high rpm colloid mill for 1 hour. Compatibility with (a) a water-soluble salt of a polyvalent metal cation ("salt") was tested by adding 2 wt% magnesium chloride (MgCl2) to the mixture and then stirring. The results shown in Table I below indicate that only one of the (b) non-ionic or cationic water-soluble or water-dispersible polymeric binder materials tested provided a salt-resistant stable dispersion ("Pass"). Titanium dioxide particles precipitated in the dispersion that failed the salt test. 9095 —— provided a salt-resistant stable dispersion ("Pass"). Titanium dioxide particles precipitated in the dispersion that failed the salt test.

[0362] Table I: Polymer Concentration and Results

[0363]

[0364] "PVP" means polyvinylpyrrolidone

[0365] Example 2

[0366] An aqueous coating solution (250 g) was prepared using the inventive polymer and Ti02containing dispersion as shown in Table I above. To 72.5 g of water was added 29.6 g of 9095 (b) binder material. To this was added 0.4 g of 106 surfactant (e.g., available from Evonik Corporation) and 125.0 g of Chemours R-960 scatterable visible light titanium dioxide particles, followed by stirring the dispersion with a homogenizer at high rpm for 1 hour. Then, between steps, 10.9 g of MgCl2.6H2O and 1.5 g of 150-50 wax particles (e.g., available from MicroPowders, Inc.) were added with stirring. Each of the resulting aqueous compositions was coated onto a clear polyethylene terephthalate substrate using a reverse gravure coating roll at a wet deposit of 4.0 g / m 2 This produced Sample 2.01-I.

[0367] Sample 2.02-I was prepared identically to Sample 2.01-I, except that 10.0 g of Polycup TM 9700 crosslinker (available from, for example, Solenis Specialty Chemicals). A Sun Chemical DPQ-173 white composition, commercially available from Sun Chemical, was used to coat the clear polyester substrate to form Sample 2.03-C. All of these samples were provided with the same aqueous coating wet deposition.

[0368] Opacity was measured on each of the resulting inkjet receiving media (determined using the TAPPI Opacity Test described above). In addition, a standard separation test pattern was printed on the three coatings using the commercial Kodak Stream Continuous inkjet printer loaded with aqueous cyan, magenta, yellow, and black pigment-based inks (commercially available KODAK Press QD packaging inks, all containing anionically stabilized colored pigments). The maximum optical density (D max ) achieved for the 3 CMY primary colors and black K aqueous pigment-based inks is shown in Table II below. The two inventive samples (2.01-I and 2.02-I) exhibited superior opacity to the comparative sample 2.03-C, which was prepared from a commercial fluid and printed with high optical density inkjet. The comparative sample also could not be inkjet printed due to excessive ink coalescence caused by lateral ink spreading, resulting in adjacent ink drops merging before water evaporated from the applied ink. The comparative coating mentioned did not contain the (a) water-soluble salt having a polyvalent cation required in the present invention, and this omission resulted in unacceptable inkjet printed images.

[0369] Table II: Hunter Opacity and Print Results

[0370]

[0371] N / A means data not available

[0372] Example 3

[0373] The Sun Chemical DPQ-173 white pre-coat composition mentioned above was evaluated for compatibility with a water-soluble salt having a polyvalent metal cation. To 100.0 g of Sun Chemical DPQ-173 white pre-coat composition was added 2.0 g of MgCl2.6H2O salt to form comparative sample 3.01-C. It was observed that the white pigments precipitated in the resulting dispersion, making it impossible to coat the aqueous composition containing the water-soluble salt.

[0374] Example 4

[0375] This example demonstrates that a separately prepared concentrated pigment dispersion can be used in the aqueous composition according to the present application. A concentrated pigment dispersion of (c) visible light scattering particles was prepared by weighing 102.9 g of water into a 500 g glass container. To this was added 57.1 g of 9095(b) binder material until the polymer was fully incorporated. Then, 240 g of Chemours R-960 titanium dioxide particles were slowly added and mixed with a colloid mill at high shear. Each of the resulting dispersions contained 60 wt% of (c) surface treated visible light scattering titanium dioxide particles.

[0376] An aqueous composition according to the present application was prepared using the pigment dispersions described in Table III below. The components mentioned were added in the amounts given in grams and in the order indicated, and stirring was performed after each addition. Selvol 6350 was delivered as a 20 wt% gel solution in water, and NBK-020322-07E polyurethane polymer made by DCM was delivered as a 40 wt% latex dispersion in DCM. TM 103 polyvinyl alcohol (e.g. available from Sekisui Specialty Chemicals), and NBK-020322-07E polyurethane polymer made by DCM was delivered as a 40 wt% latex dispersion in DCM.

[0377] Table III: Aqueous compositions of Example 4

[0378]

[0379] A comparative pre-coat composition 4.07-C was prepared similarly to the aqueous compositions described in Table III, but the main difference was that the pigment dispersion containing visible light scattering particles was not included.

[0380] All seven aqueous compositions were coated onto a polyethylene terephthalate substrate at 4.0 g / m 2 of wet deposit using a reverse gravure cylinder. The results are shown in Table IV below. As described in Example 2, a standard separation test pattern was printed on each of the resulting inventive coatings from samples 4.01-I to 4.06-I using a commercial Kodak Stream Continuous inkjet printer loaded with aqueous pigment-based ink, and the resulting prints exhibited excellent density and image quality. Comparative sample 4.07C exhibited low opacity (determined using the TAPPI opacity test described above) due to the lack of (c) surface treated visible light scattering particles.

[0381] Table IV: Results of Example 4 aqueous compositions

[0382]

[0383] Example 5

[0384] This set of examples shows that the dispersion treatment used in the foregoing examples can be applied to other pigments as (c) visible light scattering particles having various particle sizes. These dispersions were prepared in the same manner as described above in Example 4, except that the dispersions contained 50 wt.% of the visible light scattering particles (pigment particles), and the 9095 polyvinylamine (b) binder material level was set at 5 wt.% of (c) visible light scattering particles solids. The size of the resulting dispersions was determined using the Horiba particle size analyzer mentioned above, and all passed the “salt” test (described above in Example 1). These dispersions are described in Table V below.

[0385] Table V: Results of Example 5

[0386]

[0387] Example 6

[0388] This example was performed similarly to Example 2. The components were added in amounts in grams and in the order indicated according to the following Table VI. To water was first added 106 surfactant and 9095 polyvinylamine (b) binder material, after which the powdered Chemours R-960 surface treated visible light scattering titanium dioxide particles were slowly added. The mixture was stirred using a homogenizer at high rpm for 1 hour. Dry Selvol TM 103 polyvinyl alcohol was added, then gradually heated to 90°C and held for 1 hour. After cooling to 40°C, the remaining components were added with 10 minutes of stirring between each step. Each of the resulting aqueous compositions was coated onto a polyethylene terephthalate substrate using a reverse gravure coating drum at 4.0 g / m 2 of wet deposition.

[0389] Table VI: Aqueous compositions of Example 6

[0390]

[0391] PVA refers to polyvinyl alcohol

[0392] The results are shown in Table VII below, and the inkjet receiving medium obtained from the aqueous composition coating containing (c) surface-treated titanium dioxide particles that scatter visible light exhibits excellent opacity (determined using the TAPPI opacity test described above). Standard separation test patterns were inkjet printed on the various inventive coatings using a commercially available EastmanKodak Company Stream Continuous inkjet printer loaded with water-based pigment-based inks, as described above in Example 2, to provide images with excellent density and image quality. Comparative Example 6.08-C was easily inkjet printed, but it exhibited low opacity due to the lack of (c) surface-treated titanium dioxide particles that scatter visible light.

[0393] Table VII: Results of the aqueous composition in Example 6

[0394]

[0395] Example 7

[0396] The aqueous compositions formulated and used in this embodiment are similar to those described in Example 6, except that alternative (b) nonionic or cationic water-soluble or water-dispersible polymer binder materials are used. To produce a pigment dispersion containing (c) titanium dioxide particles that scatter visible light, FG polyethyleneimine (b) binder material was used. First, the binder material was added to water, and the pH was adjusted to 7.0 with 5 molar HCl. Then, powdered Chemours R-900 surface-treated titanium dioxide was slowly added. The resulting mixture was stirred at high rpm for 1 hour using a homogenizer. The following steps were performed sequentially: 106 surfactant and dried Selvol TM Add 103% polyvinyl alcohol, then gradually heat to 90°C and maintain for 1 hour. After cooling to 40°C, add [the following ingredients] while stirring for 10 minutes between steps. 9095 Polyethyleneamine (b) adhesive material, MgCl2 and Polycup TM 9700 crosslinking agent. Apply using a reverse gravure coating roller at 4.0 g / m². 2 The wet deposition process involves coating the resulting aqueous compositions onto a polyethylene terephthalate substrate to form an inkjet receiving medium. FG polyethyleneimine and The 9095 polyethyleneamine material was varied in the two formulations indicated in Table VIII below. The opacity of each resulting inkjet receiving medium was analyzed (using the TAPPI opacity test described above) and printed using a continuous inkjet printer as described above. The comparative samples shown in Table VIII were prepared in the same manner as comparative sample 6.08-C. Both inventive samples 7.01-I and 7.02-I achieved high opacity and excellent printing results, but comparative sample 7.03-C exhibited low opacity due to the lack of (c) surface-treated visible light-scattering particles in the topcoat composition beneath the inkjet-printed image.

[0397] Table VIII: Results of Example 7

[0398]

[0399] Example 8

[0400] This embodiment demonstrates that, in order to reduce the overall cost of the water-based composition, a white pigment (Chemours R-900, surface-treated titanium dioxide particles that scatter visible light) and a less expensive filler (KaMin) were used. The efficacy of the combination of 90, kaolin. The components are added in grams and in the order indicated according to Table IX below. The same procedure as described above in Example 7 is used. KaMin is added after the surface-treated visible light-scattering titanium dioxide particles of Chemours R-900(c). 90% additive or alternative to Chemours R-900(c) surface-treated visible light-scattering titanium dioxide particles with KaMin 90% additive.

[0401] Table IX: Aqueous Composition of Example 8

[0402]

[0403] PVA refers to polyvinyl alcohol; PEI refers to polyethyleneimine.

[0404] The zeta potential of the aforementioned aqueous composition was analyzed before it was coated onto the substrate. Comparative sample 8.08-C contained no particles that scatter visible light, therefore the zeta potential was not applicable. All inventive samples 8.01-I to 8.07-I exhibited positive zeta potentials, which makes the aqueous composition stable in the presence of (a) water-soluble magnesium chloride salt. A reverse gravure coating roller was used at 4.0 g / m². 2 Wet deposition was used to coat the aqueous compositions onto a polyethylene terephthalate (PET) support. Chemours R-900(c) surface-treated visible light-scattering titanium dioxide particles and KaMin... 90 The particles were varied in the formulations indicated in Table X below. The opacity was analyzed for each coating (using the TAPPI Opacity Test described above), and printing was performed using a continuous inkjet printer. The results for each inventive aqueous composition containing (c) surface-treated, visible light-scattering particles indicate the efficacy of combining one or more of these types of such particles to achieve the desired opacity and cost, while maintaining excellent print quality as part of a continuous inkjet system. However, comparative aqueous composition 8.08-C exhibited low opacity due to the lack of (c) surface-treated, visible light-scattering particles in the inkjet printed surface of the inkjet receiving medium.

[0405] Table X: Results of Example 8

[0406]

[0407] Example 9

[0408] This example shows that zeta potential measurements predict when pigment dispersions containing (c) surface-treated, visible light-scattering particles will be stable in the presence of (a) water-soluble salt such as magnesium chloride. Each dispersion was prepared by dissolving (b) a non-ionic or cationic water-soluble or water-dispersible polymeric binder material in water, adding dry pigment containing (c) surface-treated, visible light-scattering particles, and then mixing the dispersion with a homogenizer at high rpm for 1 hour. In all cases, the pigment concentration was 5 wt.%. The first four dispersions did not contain (f) a dispersion aid, and the first three dispersions contained a buffer solution instead of water. The (f) dispersion aid levels shown in Table XI below are given as a wt.% of pigment loading. Stability to (a) water-soluble salt was determined by adding 2 wt.% MgCl2to the dispersion after it was prepared. Inventive dispersions that remained stable are listed as “Pass”, while comparative dispersions from which (c) surface-treated, visible light-scattering particles precipitated are listed as “Fail”.

[0409] Table XI: Example 9 Dispersion Parameters and Test Results

[0410]

[0411] Without exception, for (a) water-soluble magnesium chloride salt, the inventive 9.05-I and 9.06-I dispersions having positive zeta potential were stable, but the comparative dispersions outside the invention were not.

[0412] Example 10

[0413] To 224 g of distilled water was added 0.75 g of 106 surfactant and 47.6 g 9095 polyvinylamine. To this solution was added 150 g Chemours R-960 to make a dispersion of (c) surface-treated visible light-scattering titania particles. Each resulting dispersion was then stirred in a colloid mill for 3 hours with a small sample taken every 30 minutes. After milling, 33.5 g of dry Selvol 5400® TM 103 polyvinyl alcohol and heated to 90 °C for 2 hours with a small sample taken every 30 minutes. After cooling to 40 °C, 19.6 g of MgCl2.6H2O was added to each dispersion and stirred for 10 minutes to make an aqueous composition. A total of 12 samples were taken from each aqueous composition and their zeta-potential was measured and particle size was measured using the Horiba instrument described above. The results are shown in Table XII below. All samples, except the first two, had fine particle size and positive zeta-potential. It should be noted that positive zeta-potential alone should not be used as a measure of optimal aqueous composition, as large particle size can indicate aggregated visible light-scattering particles.

[0414] Table XII: Example 10 sample results taken during dispersion and aqueous composition preparation

[0415] Sample Method step Method step time (min) Average diameter (pm) Zeta potential (mV) 10.01-I Dispersion 0 229.82 32.9 10.02-I Dispersion 30 0.73 25.0 10.03-I Dispersion 60 0.09 25.1 10.04-I Dispersion 90 0.09 22.5 10.05-I Dispersion 120 0.10 22.6 10.06-I Dispersion 150 0.10 20.5 10.07-I Dispersion 180 0.10 23.2 10.08-I Heated at 90 °C 30 0.08 11.9 10.09-I Heated at 90 °C 60 0.08 15.1 10.10-I Heated at 90 °C 90 0.09 14.4 10.11-I Heated at 90 °C 120 0.08 14.8 10.12-I At the time of salt addition 10 0.09 14.4

[0416] Example 11

[0417] This example shows the utility of (b) non-ionic or cationic water-soluble or water- dispersible polymeric binder material according to the present application to stabilize various pigments containing visible light-scattering particles for use in aqueous compositions and topcoat compositions according to the present application. Each dispersion sample was prepared using Sigma-Aldrich low molecular weight polyethyleneimine (f) dispersion aid to shift the ionic charge in the pigment dispersion. Each aqueous dispersion (100 g) was prepared so that it contained 10 wt% of a pigment containing (c) visible light-scattering particles. Each candidate pigment was tested with and without the addition of (f) dispersion aid to each dispersion. The dispersions containing (b) binder material were adjusted to a nominal pH of 6 using 1 molar (concentration) hydrochloric acid. All dispersions were stirred using a homogenizer at high rpm for 1 hour. Particle size and zeta-potential were measured in the resulting aqueous compositions containing (a) water-soluble salt to explain the results of the MgCl2salt test described previously.

[0418] Table XIII: Example 11 sample results

[0419]

[0420] The results shown above indicate that all test pigments containing (c) light scattering particles have an inherent negative surface charge that makes the comparative aqueous compositions without (b) binder material incompatible with (a) water soluble multivalent metal salt. With (b) binder material, all pigments undergo a surface charge reversal that results in different average particle sizes and aqueous composition tolerance to (a) water soluble multivalent metal salt.

[0421] Example 12

[0422] This example shows the ability of (b) non-ionic or cationic water soluble or water dispersible polymeric binder material according to the present application to stabilize Chemours R-960 surface treated light scattering titanium dioxide particles under a range of pH conditions. Each dispersion (100 g) was prepared so that it contained 5 wt% pigment and a (b) binder material level of 10% of the pigment solids. The pH of the dispersion formulation was adjusted after the (b) binder material had been dissolved in distilled water. pH adjustment was performed using 1% hydrochloric acid and 0.5 molar (concentration) sodium hydroxide. After the pH adjusted (b) binder material solution was added to the pigment, each dispersion was stirred using a homogenizer at high rpm for 1 hour. The final aqueous compositions containing (a) water soluble salt were tested for zeta potential and 2% MgCl2salt stability. The results are shown in Table XIV below. All three (b) binder materials provided (c) surface treated light scattering particles with a positive surface charge that were compatible with (a) water soluble salt at pH ranging from 6-9.

[0423] Table XIV: Results for Example 12 samples

[0424]

[0425] *“PEI” refers to polyethyleneimine

[0426] Example 13

[0427] This example evaluates a series of different (b) binder materials for their ability to act as (f) dispersion aids and to stabilize Chemours R-960 pigment containing (c) visible light scattering particles according to the present application. Each dispersion (100 g) was prepared so that it contained 5 wt% pigment and a (b) binder material level of 10 wt% of the pigment solids. After the (b) binder material had been dissolved in distilled water, each dispersion formulation was adjusted to a pH of 7 using 1 wt% hydrochloric acid or 0.5 molar (concentration) sodium hydroxide depending on which direction the solution needed to travel to achieve a final pH of 7. After the addition of the pigment to the pH adjusted (b) binder material solution, each dispersion was stirred using a homogenizer for 1 hour at high rpm. Each final aqueous composition was subjected to zeta potential, Horiba particle size measurements, and 2 wt% MgCl2salt testing. The results are shown in Table XV below. Without exception, the (b) binder materials that were able to achieve a charge reversal and a positive zeta potential were compatible with the (a) water soluble salt in all samples. Additionally, the positively charged pigment particle dispersions were on average smaller than the negatively charged pigment particle dispersions.

[0428] Table XV: Results for Example 13 samples

[0429]

[0430] Selvol TM The polymers were obtained from Sekisui Specialty Chemicals

[0431] Example 14

[0432] This example evaluates P and The FG polymer materials were evaluated for their ability to produce three different pigment dispersions containing (c) surface treated visible light scattering titania particles. Each dispersion (100 g) was prepared so that it contained 30 wt% Ti02particles and a (b) binder material level of 5 wt% or 15 wt% of the Ti02solids. After the referenced (b) binder material had been dissolved in distilled water, each dispersion formulation was adjusted to a pH of 7 using 5 molar (concentration) hydrochloric acid. After the addition of the Ti02particles to each pH adjusted polymer solution, the resulting dispersions were stirred using a homogenizer for 1 hour at high rpm. Each final aqueous composition was subjected to zeta potential, particle size, and 2 wt% MgCl2salt testing. The results are shown in Table XVI below. The results indicate that the referenced polymers were able to successfully disperse all three Ti02containing pigments at both (b) binder material to Ti02percentages to provide aqueous compositions according to the present application for use in pretreating substrates for inkjet printing.

[0433] Table XVI: Results for Example 14 samples

[0434]

[0435] Example 15

[0436] The aqueous compositions prepared and used in this example were similar to those described above in Example 7. First, 74.5 g of water was added to each of the following solutions containing (b) a non-ionic or cationic water-soluble or water-dispersible polymeric binder material: P (13.5 g), and the pH of the resulting (b) binder material solution was adjusted to 7.0 using 5 molar (concentration) HC1. Then, 45.0 g of powdered Chemours R900 titanium dioxide particles were slowly added to each (b) binder material solution to produce a dispersion of (c) surface-treated visible light-scattering titanium dioxide particles. The resulting mixture was stirred for 1 hour. To each, 0.23 g of 106 surfactant and 9.28 g of dry Selvol TM 103 polyvinyl alcohol, then gradually heated to 90 °C and held for 1 hour. After cooling to 40 °C, 6.53 g of MgCl2and 0.96 g of 9700 crosslinker. A magnetic stir bar was used to mix the samples (except for one sample) throughout all steps. In inventive sample 15.02-I, high shear homogenization was added to the mixing during the 1 hour dispersion step. The results are shown in Table XVII below, where it was observed that the degree of mixing in the dispersion step had little effect on the zeta potential of the final aqueous composition.

[0437] Table XVII: Results for Example 15 samples

[0438] Sample Dispersion mixing Zeta potential (mV) 15.01-I Magnet 4.8 15.02-I Magnet + homogenizer 4.9

[0439] Example 16

[0440] This example evaluated Selvol TM Ultiloc 5003 ethylene amine / ethylene vinyl copolymer (available from Sekisui Specialty Chemicals) as a (b) non-ionic or cationic water-soluble or water-dispersible polymeric binder material to stabilize a dispersion of (c) surface-treated visible light-scattering titanium dioxide particles.

[0441] Each dispersion (100 g) was prepared so that it contained a (b) binder material level as a variable weight percent of Ti02 solids. After the (b) binder material had been added to distilled water, each dispersion was adjusted to a pH of 7.5 using 5 molar (concentration) hydrochloric acid. The (b) binder material was in dry form and dissolved and held for 1 hour during gradual heating to 90 °C. After cooling to 40 °C, Chemours R-900 titanium dioxide particles were added to each (b) binder material dispersion and mixed for 1 hour using a magnetic stir bar to produce a (c) dispersion of surface treated, visibly scattering titanium dioxide particles. Each final aqueous composition was subjected to zeta potential and 2 wt% MgCl2 salt testing (described above in Example 1). The results are shown in Table XVIII below, where it can be seen that Selvol TM Ultiloc 5003 ethylene amine / ethylene vinyl alcohol copolymer was necessary to shift the zeta potential to positive and stabilize the dispersion containing (a) water soluble salt.

[0442] Table XVIII: Results for Example 16 samples

[0443]

[0444] Example 17: Preparation of inkjet printed articles using aqueous compositions:

[0445] Commercially available primerless, non-porous polymer film substrates, such as commonly used clear biaxially oriented polyethylene terephthalate (BOPET) and aluminum- metallized BOPET (m-BOPET) films and Jindal’s BICOR TM LPX-2 biaxially oriented polypropylene (BOPP) as a substrate to make inkjet receiving media according to the present application.

[0446] Aqueous composition:

[0447] The following aqueous compositions were made according to the present application and used in the following examples to form topcoat compositions on the various substrates mentioned above:

[0448] These four aqueous compositions (01N-1, 08C-1, 08C-2B, and 10B-1) were prepared similarly to those described above, but with different materials added in varying order. The components were added in the amounts in grams according to Table XIX below.

[0449] Table XIX

[0450]

[0451] Aqueous composition 01N-1:

[0452] First added to water 106 and 9095, then slowly add powdered Chemours R960 titanium dioxide as (c) visible light scattering particles. Stir the mixture at high rpm for 1 hour using a homogenizer. Add dried Selvol TM 103, then gradually heat to 90°C while well mixed and maintain for 1 hour. After cooling to 40°C, add the remaining components in the listed order while stirring for 10 minutes between steps.

[0453] Aqueous composition 08C-1:

[0454] First add water 106, then slowly add powdered Chemours R900 titanium dioxide as (c) visible light scattering particles. Stir the mixture at high rpm for 2 hours using a homogenizer. Add dried Selvol TM Ultiloc5003 was used, and the pH was adjusted to 7.5 with concentrated HCl, then added... 9095. After this, gradually heat to 90°C under high shear mixing and maintain for 1 hour. After cooling to 40°C, add the remaining components in the listed order while stirring for 10 minutes between steps.

[0455] Aqueous composition 08C-2B:

[0456] First add water 106 and 9095, then slowly add powdered Chemours R900 titanium dioxide as (c) visible light scattering particles. Stir the mixture at high rpm for 2 hours using a homogenizer. Add dried Selvol TM 103, then gradually heat to 90°C under high shear mixing and maintain for 1 hour. After cooling to 40°C, add the remaining components in the listed order while stirring for 10 minutes between steps.

[0457] Aqueous composition 10B-1:

[0458] First add water 106, then slowly add powdered Chemours R900 titanium dioxide as (c) visible light scattering particles. Stir the mixture at high rpm for 2 hours using a homogenizer. Add dried Selvol TM Ultiloc 5003, and adjusted the pH to 7.5 using concentrated HCl, then added... 9095. After this, gradually heat to 90°C under high shear mixing and maintain for 1 hour. After cooling to 40°C, add the remaining components in the listed order while stirring for 10 minutes between steps.

[0459] As described above, the topcoat composition was formed on the identified substrates using the appropriate aqueous composition according to the present application. The level of titanium dioxide in the resulting topcoat composition was reduced by 20%. Where necessary, the substrates were treated with a corona discharge device prior to application of the aqueous composition to provide acceptable wetting at a treatment energy density of about 80 W-min / m 2 of the topcoat composition. A substantially similar aqueous composition was then applied to the substrates using an RK PrintCoat Instruments Ltd. Rotary Koater with reverse gravure or smooth roll offset gravure coating procedures.

[0460] Typically, the reverse gravure coating process delivered 5.0-7.5 cm 3 / m 2 of the aqueous composition. The single station gravure printing desirably used a 60° hex engraving, 250 pli / inch (98.4 pli / cm), 14.8 BCM cylinder (100 lines / cm, 23.0 cc / m 2 ). Reverse gravure coating transfer efficiency can be varied by changing the ratio of the coating roll to the winding speed ratio; higher speed ratios give lower wet coverage. The speed ratio was varied from ~1.0 to 1.8. In gravure offset, the coating is first transferred to a smooth roll, which is pressed against the web by a metal backup roll to form a nip with the web. The gravure roll, smooth transfer roll, and metal backup roll are all meshed together to move at a common speed. Typically, the offset coating process delivered 5.8-6.3 cm 3 / m 2 of the aqueous composition. In both the reverse coating and offset coating processes, the coated substrate was dried in-line using a hot air dryer that produced a web temperature of at least about 40°C, resulting in a dry topcoat composition coverage range of 1.8-2.6 g / m 2 on inkjet receptive media with an opacity range of 52-56%.

[0461] The resulting inkjet receptive media were then printed in-line with one or more CIJ impression systems, or were each wound on a core for subsequent single-page fed printing on a benchtop device that employed pressurized containers for ink delivery using a single color 1 inch (2.54 cm) print head, or with a full-width four-color CIJ printing system that was equipped with pumps to pressurize the circulating inks using fluid (master supply) stations. In each experiment, the inkjet receptive media were printed with an aqueous cyan, magenta, yellow, or black pigment-based ink (commercially available KODAK Press QD Packaging Inks, all of which contained anionically stabilized colored pigments).

[0462] In-line coating and printing:

[0463] In a representative procedure, the ink reservoirs of a web-fed continuous inkjet printing test bench jig were loaded with aqueous pigment-based cyan and magenta inks. The web-fed printing test jig was connected in-line downstream of an RK20 PrintCoat Instruments Ltd. Rotary Koater gravure coater, which allowed the web-fed uncoated flexible transparent or metallized substrate to be first pre-coated with an aqueous composition according to the present application to form a white topcoat composition (or layer) in the inkjet receptive medium as described previously, dried at least partially, and then printed with one or more in-line KODAK Stream inkjet printers using the aqueous pigment-based cyan and magenta inks to form a colored image on the white topcoat composition (or layer) of the inkjet receptive medium. The S10 press system was inkjet printed using full-width (4.25 inches (10.8 em)) Stream TM 600 nozzles / inch (236 nozzles / centimeter) continuous inkjet printhead modules that enable 600 x 600 dots / inch (236 x 236 dots / centimeter) addressing capability or 600 x 900 dpi (236 x 354 dpcm). The corresponding drop volumes at these resolutions are about 9.8 and 11.4 picoliters, respectively. The press system consists of the following elements:

[0464] (1) two fluid system stations that are capable of (a) pressurizing the aqueous cyan and magenta pigment-based inks above 60 psid (0.41 MPa) to produce ink volume flow rates up to about 2 L / min; (b) delivering the pressurized anionically stabilized aqueous cyan and magenta pigment-based inks from the continuous inkjet printhead drop generator modules as shown in Table XX below; (c) returning unprinted (or unused) ink to their respective fluid system ink reservoirs under vacuum; (d) detecting the reservoir ink concentrations by resistivity measurements, and if the aqueous cyan or magenta pigment-based ink has been concentrated by water evaporation, replenishing the ink with make-up fluid, and if it is consumed in printing and at the correct colorant concentration, instead adding more of the aqueous cyan or magenta pigment-based ink to their respective ink reservoirs; and (e) providing the printheads with printhead cleaning and storage fluids to flush the nozzles and plumbing to facilitate resumption of accurate printing after fouling by dried ink accumulation, and to shut down the system for safe storage over a significant duration;

[0465] (2) a web transport system with an encoder to detect and accurately adjust the transport speed of the substrate, and synchronized with the control unit to initiate and terminate image printing;

[0466] (3) Continuous inkjet printhead PIC cartridge assemblies each comprising (a) KODAK A printer ejection module having MEMS silicon-based droplet generators for forming print and non-print droplets of an aqueous pigment-based ink, and a Coanda slot for capturing non-print droplets when the printer is not printing an image file or when the printer is not printing a given pixel even though it is printing an image file; (b) a non-print droplet deflection device that creates a deflection zone intersecting a curtain of droplets provided by positive and negative airway assemblies to direct non-print droplets to the Coanda slot; and (c) an ink return line to a fluid system ink reservoir; and

[0467] (4) A print controller that (a) synchronizes web space position to data fed to the ejection module, and also (b) transmits electrical signals to the ejection module CMOS circuitry that uses nozzle plate heater pulse pattern to translate rasterized images into pixel-by-pixel ink flow stimulation instructions by means of an optimized waveform to generate, as needed, non-print capture and print droplets of aqueous pigment-based ink delivered at pixel locations on the surface of a print substrate.

[0468] Each fluid system utilizes Micropump Inc. Series GJ-N23DB380A gear pumps to deliver ink through Pall Corp. disposable filter assembly capsule filters (DFA4201ZU0045) containing 0.45 μιη nominal effective pore size GF-HV glass fiber media with a pressure drop at the nozzle plate of about 65 psid (0.45 MPa) to generate a uniform droplet velocity of about 20 m / s. The fluid system gear pump speed settings are adjusted constantly according to the system instructions to provide and maintain a constant fluid pressure at the ejection module to produce the required uniform droplet velocity. The system parameter settings required to determine proper ejection and accurate replenishment of aqueous cyan or magenta pigment-based ink are recorded into a computer file called "inkdex" to enable the ability to reproduce the same on other systems, for example, equipped with dual production KODAK Printing is performed on a S10 roll-fed press of the Impresstek® press system. Deflected non-printing ink drops are captured on the Coanda channel and returned to the fluid system ink tank under vacuum. Continued operation of the press in the non-printing drop capture mode results in gradual evaporation of the aqueous ink solvent carrier. The aqueous cyan and magenta pigment-based ink concentrations are maintained within about 5% of the original aqueous pigment-based ink concentrations by adding a replenishment fluid containing no particles thereto (if the aqueous cyan and magenta pigment-based ink concentrations become more than about 5% concentrated based on ink resistivity measurements). The test target is raster image processed to produce digital print signal instructions for each pixel location at a proper test substrate transport speed of 600 pixels per inch (ppi) (236 pixels per centimeter (ppcm)).

[0469] Various test images are printed at different substrate transport speeds - using 600 nozzles per inch (236 nozzles per centimeter) in a production print head assembly configuration The press jet module produces a 4.25 inch (10.8 cm) jet swath print.

[0470] To investigate ink durability and ink cohesion strength of the inkjet printed article, it is useful to either 1) print each color individually with a range of 10-100% tint series (in 10% steps) or 2) print the magenta tint series in registration with a 100% cyan tint image. The resulting inkjet printed article is dried in-line using a 0.7 m hot air dryer and a high speed air knife in succession and wound in roll form and then cut into sections in sheet form for further testing. The drying system produces an ink surface temperature of at least about 43°C for the single color inkjet printed and an ink surface temperature of at least about 40°C for the dual color inkjet printed. The speed is typically 40 feet per minute (12 meters per minute).

[0471] To evaluate the level of ink drying and the ability of the white topcoat composition in the ink receiving layer to absorb and handle ink humectants, samples of the inkjet printed article as described above are subjected to either a finger rub test or an ink cohesion tape test for evaluation. The finger rub is performed using a back and forth rub; and the rub is performed on a balance to adjust the rub pressure to give about 300 g load after which the rub is performed. The ink movement level from the finger rub is rated as good (no ink movement), fair (slight ink movement), or poor (large ink movement) at a given ink deposition in the single color or dual color image.

[0472] With respect to the tape test, a piece of 3M TM A clear tape was placed on the top surface of the inkjet printed article when resting on a solid bench top, with 4-6 firm presses of the tape backing with a human finger. The tape was then manually and slowly peeled from the sample article over a 6-8 second duration. The inkjet printed image was observed for any transfer to the tape (cohesive or adhesive failure), and the results were rated as good (no ink transfer), fair (some ink transfer), or poor (large amounts of ink transfer). Inks that were fully dried and treated with a humectant would have strong adhesion to the tape in the adhesive test, with little to no ink transfer to the tape. Similar tests were performed in the unprinted areas. After peeling, the tape was observed for any transfer of the white topcoat composition to the tape (considering % area removal).

[0473] The following Table XX indicates that good adhesion of the unprinted areas was observed on clear BOPP and BOPET and metallized PET substrates. Little to no opaque ink receptive layer was removed using the tape test. Similarly, the ink cohesion was good to prevent little to no ink removal or no ink removal using the tape test. The finger rub test showed that in some conditions, the overcoat varnish can be useful to provide the best dry rub test.

[0474] In the column labeled "Ink (% Humectant)" in the following Table XX, "Gly" is an identifier for glycerol, "1,2-PD" is an identifier for 1,2-propanediol, and "TEG" is an identifier for triethylene glycol.

[0475] Table XX: Online Coating and Printing Summary

[0476]

[0477] Single sheet multi-color jigs for printing on white inkjet receiving media:

[0478] The fixture consists of the following elements: (1) a pressurized reservoir fluid system for each color ink (water-based cyan, magenta, yellow, and black pigment-based inks as described above) capable of pressurizing the water-based pigment-based inks above 60 psid (0.41 MPa) to produce ink volumetric flow rates through a typical 600 nozzle / inch (236 nozzle / cm) MEMS silicon nozzle plate of about 63 mL / min / inch (24.8 mL / min / cm) of print head nozzle plate; (2) a fluidic manifold that delivers the pressurized inks to a small-format KODAK a print drop and a non-print drop of an aqueous pigment-based ink using a 4.16 inch (10.57 cm) nozzle plate; (3) a drop selection system consisting of: (a) a gutter that captures non-print drops when the printer is not printing an image file or when it is not printing a given pixel even if it is printing an image file; (b) a non-print drop deflection device that creates a deflection zone that intersects with a curtain of drops provided by positive and negative airway assemblies to direct those drops to the gutter, and (c) a catch tray that is connected to a waste fluid line to remove unprinted ink; (4) a vacuum drum that is capable of carrying a piece of porous media (e.g., uncoated free sheet paper) or non-porous media (e.g., coated or uncoated polymeric film) and continuously rotating it at a precise speed that is synchronized with the control unit to simulate web transport of a roll of print substrate in the form of a web; and (5) a print controller that (a) controls the print drum speed and synchronizes the drum position in accordance with the data fed to the small-jet module drop generator and also (b) transmits electrical signals to the jet module CMOS circuit that uses nozzle plate heater pulse pattern to translate rasterized images into pixel-by-pixel ink flow stimulation instructions by means of an optimized waveform to generate, as needed, non-print capture ink drops and print drops that are delivered at precise print substrate surface pixel locations.

[0479] The print apparatus drum was loaded with a single sheet of inkjet receiving media according to the present invention having a topcoat composition on a polymeric film substrate, the backside of which was affixed to a sheet of paper for ease of handling. The drum was moved under each color module and rotated at 325 ft / min (98.5 m / min) to print in 4-color register. The aqueous pigment-based ink used in these tests was commercially available KODAK QD Pack ink. The printed sheet was removed and allowed to air dry overnight at ambient temperature and humidity or was incubated in a laboratory oven at 60 °C for about 5 minutes before testing and further processing. This process was used to generate color linearization and IT8 color print targets to develop ICC color profiles for 4-color web printing. Color profiles were developed for the opaque aqueous composition 01N-1 applied at 3.4 g / m 2 The opacity of the white topcoat composition on LPX-2B OPP was 57%.

[0480] Four color web printing of pre-coated white inkjet receiving media:

[0481] Similar to the printing system just described for a two-color system, a multi-color web printing system was used, which has enhanced drying and in-track registration. The engineering press was capable of using the KODAK The S-Series print module prints up to seven colors. In this printer, two clamshell dryers are placed around a 1.6 m diameter drum. On the first third of the drum circumference are 12 mid-infrared lamps, which are located between the hot exhaust ports. This printer allows for higher speed printing and allows for the production of a final print roll for subsequent post-coating of varnish on a Rotary Koater.

[0482] The opaque aqueous composition 01N-1 applied at 3.4 g / m 2 of dry deposition coated several LPX-2 BOPP rolls. Several thousand feet (or meters) of customer's four color consumable hot dog (Frankfurter) packaging jobs were printed on the mentioned printer at a speed of 250 ft / min (75.8 m / min). The image quality and detail were excellent and there was no ink smearing in the machine or damage to the printed image.

[0483] Application of aqueous overprint varnish to inkjet printed articles:

[0484] The aqueous varnish SunEvo TM EV-AW002 from Sun Chemical (Northlake, IL, USA) was applied to the Sapphire XGV hot dog (Frankfurter) print roll described above using offset gravure printing. This post-coating process delivered 5.5-6.5 cm 3 / m 2 of wet deposited varnish. Single station gravure printing used 60° hexagonal engraving, 250 liters / inch (98.4 liters / cm), 14.8 BCM cylinder (100 lines / cm, 23.0 cm 3 / m 2 ). The inkjet printed and varnished article was dried in-line using 3 x 0.7 m hot air dryers producing a web temperature of at least about 50 °C, resulting in a dry varnish layer coverage range of 2.5-2.9 g / m 2 . The resulting coating had a gloss measured at 60° of about 18 units.

[0485] Parts List

[0486] 10 inkjet receiving medium

[0487] 20 inkjet recording medium

[0488] 30 inkjet printed article

[0489] 100 substrate

[0490] 110 topcoat composition

[0491] 200 support

[0492] 210 first layer

[0493] 215 substrate

[0494] 220 topcoat composition

[0495] 300 substrate

[0496] 310 water-impermeable support

[0497] 320 first layer

[0498] 330 topcoat composition

[0499] 340 water-based inkjet printed image or layer

[0500] 350 post-printed functional layer

Claims

1. An aqueous composition for pretreating a substrate prior to inkjet printing on the substrate, the aqueous composition having at least 2% solids and up to and including 90% solids, and the aqueous composition comprising the following (a), (b), (c), and (f) components: (a) water soluble salts of one or more polyvalent metal cations, the (a) water soluble salts of one or more polyvalent metal cations being present in an amount of at least 0.5 wt% and up to and including 30 wt%; (b) one or more non-ionic or cationic water soluble or water dispersible polymeric binder materials, present in an amount of at least 0.1 wt% and up to and including 30 wt%; (c) surface treated visible light scattering titanium dioxide or zinc oxide particles that have been surface treated using one or more (f) dispersing aids such that the aqueous composition has a stable zeta potential greater than +10 millivolts, and the (c) surface treated visible light scattering titanium dioxide or zinc oxide particles are present in an amount of at least 5 wt% and up to and including 60 wt%; and (f) dispersing aids for the (c) surface treated visible light scattering titanium dioxide or zinc oxide particles, the (f) dispersing aids being cationic on a cumulative charge basis, and present in an amount of at least 0.2 wt% and up to and including 50 wt% based on the total weight of the (c) surface treated visible light scattering titanium dioxide or zinc oxide particles, wherein the amounts of the (a), (b), and (c) components are based on the total weight of the aqueous composition.

2. The aqueous composition of claim 1, wherein the (c) surface-treated, visible light- scattering titanium dioxide or zinc oxide particles exhibit a D[4,3] of at least 0.04 µm and up to and including 2 µm, as measured by a particle analyzer that provides a volume-weighted particle size distribution. 50 Particle size.

3. The aqueous composition of claim 1 or 2, further comprising: (d) particles different from the (c) component, the (d) particles having a Rockwell hardness less than or equal to R90, and present in an amount of at least 0.02 wt% and up to and including 5 wt% based on the total weight of the aqueous composition.

4. The aqueous composition of claim 1 or 2, further comprising: (e) crosslinkable polymeric materials different from all of the (a), (b), and (c) components, and present in an amount of at least 0.1 wt% and up to and including 30 wt% based on the total weight of the aqueous composition.

5. The aqueous composition of claim 1, wherein the (f) dispersing aids are polymers having at least one protonated nitrogen atom, and present in the aqueous composition in an amount of at least 1 wt% and up to and including 20 wt% based on the total weight of the (c) surface treated visible light scattering titanium dioxide or zinc oxide particles.

6. The aqueous composition of claim 1 or 2, wherein the (b) one or more non-ionic or cationic water soluble or water dispersible polymeric binder materials comprise one or more of the following: polyvinyl alcohol, polyethylene imine, polyethylene oxide, polyvinyl amine, copolymers derived at least in part from ethylene alcohol and ethylene oxide, copolymers derived at least in part from ethylene amine and ethylene alcohol.

7. The aqueous composition of claim 1 or 2, wherein the (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder material comprises at least a polyvinylamine, a polyethyleneimine, a polyvinyl alcohol, a copolymer derived at least in part from a vinyl amine and a vinyl alcohol, or a combination of two or more of these polymeric materials.

8. The aqueous composition of claim 5, wherein the (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder material is the same as the (f) dispersion aid.

9. The aqueous composition of claim 1 or 2, wherein the (a) water-soluble salt of one or more polyvalent metal cations is one or more water-soluble salts of magnesium +2, calcium +2, barium +2, zinc +2, and aluminum +3.

10. An inkjet receiving media having an opacity of at least 50% and a colorimetry defined by an a* value of at least -5 and up to and including +5 and a b* value of at least -5 and up to and including +5, and comprising a substrate and a topcoat composition disposed on a surface thereof, the topcoat composition comprising the following (a), (b), (c), and (f) components: (a) a water-soluble salt of one or more polyvalent metal cations, the (a) one or more water-soluble salt being present in an amount of at least 0.4 wt% and up to and including 40 wt%; (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder material present in an amount of at least 0.5 wt% and up to and including 90 wt%; (c) surface-treated visible light scattering titania or zinc oxide particles that have been surface treated using one or more (f) dispersion aids, and present in an amount of at least 6 wt% and up to and including 90 wt%; and (f) a dispersion aid for the (c) surface-treated visible light scattering titania or zinc oxide particles, the (f) dispersion aid being cationic on a cumulative charge basis, and present in the topcoat composition in an amount of at least 0.2 wt% and up to and including 50 wt% based on the total weight of the (c) surface-treated visible light scattering titania or zinc oxide particles, wherein the amounts of the (a), (b), and (c) components are based on the total weight of the topcoat composition, and wherein the substrate is a transparent or metallized polymeric film.

11. The inkjet receiving media of claim 10, wherein the topcoat composition has a dry solids coating weight of at least 0.1 g / m 2 and up to and including 10 g / m 2 2.

12. The inkjet receiving media of claim 10 or 11, wherein the substrate is a transparent biaxially oriented polyethylene terephthalate (BOPET) film, an aluminum- metallized BOPET (m-BOPET) film, or a biaxially oriented polypropylene (BOPP) film.

13. The inkjet receiving media of claim 10 or 11, wherein the substrate has an L* value of 50 or less.

14. The inkjet receiving media of claim 10 or 11, wherein the topcoat composition is disposed on the substrate surface as a continuously distributed layer.

15. The inkjet receiving media of claim 10 or 11, wherein the topcoat composition is disposed on the substrate surface as a pattern.

16. The inkjet receiving media of either of claims 10 or 11, wherein the substrate comprises a hydrophobic surface prior to disposing the topcoat composition thereon, the hydrophobic surface is impervious or substantially impervious to aqueous or pigment-based ink compositions, and the topcoat composition provides a hydrophilic surface relative to the hydrophobic surface of the substrate.

17. The inkjet receiving media of either of claims 10 or 11, wherein the topcoat composition further comprises: (d) a different particulate than the (c) component, the (d) particulate having a Rockwell hardness of less than or equal to R90, and present in an amount of at least 0.06 wt% and up to and including 10 wt% based on the total weight of the topcoat composition.

18. The inkjet receiving media of either of claims 10 or 11, wherein the topcoat composition further comprises: (e) a cross-linkable polymeric material different from all of the (a), (b), and (c) components, and present in the topcoat composition in an amount of at least 0.1 wt% and up to and including 30 wt% based on the total weight of the topcoat composition.

19. The inkjet receiving media of either of claims 10 or 11, wherein the (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder materials comprise a polyvinyl alcohol, a polyethylene imine, a polyethylene oxide, a polyvinyl amine, a copolymer derived at least in part from vinyl alcohol and ethylene oxide, a copolymer derived at least in part from vinyl amine and vinyl alcohol, or a combination of two or more of these materials.

20. The inkjet receiving media of either of claims 10 or 11, wherein the (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder materials comprise at least a polyvinyl amine, a polyvinyl alcohol, a copolymer derived at least from vinyl amine and vinyl alcohol, or a combination of two or more of these polymeric materials.

21. The inkjet receiving media of claim 10, wherein the (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder materials are the same as the (f) dispersion aid.

22. A method for providing inkjet receiving media, the method comprising, in order: A) providing a substrate; and B) disposing an aqueous composition onto at least one surface of the substrate to provide a topcoat composition on the at least one surface, the aqueous composition having at least 2% solids and up to and including 90% solids, and comprising the following (a), (b), (c), and (f) components: (a) one or more water-soluble salts of polyvalent metal cations, the (a) one or more water-soluble salts present in an amount of at least 0.5 wt% and up to and including 30 wt%; (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder materials in an amount of at least 0.1 wt% and up to and including 30 wt%; (c) titanium dioxide or zinc oxide particles that scatter visible light, which have been surface treated with one or more (f) dispersion aids, such that the aqueous composition has a stable zeta potential greater than +10 millivolts, and the (c) titanium dioxide or zinc oxide particles that scatter visible light are present in an amount of at least 5 weight % and up to and including 60 weight %; and (f) a dispersion aid for the (c) surface treated titanium dioxide or zinc oxide particles that scatter visible light, the (f) dispersion aid being cationic on a cumulative charge basis, and present in an amount of at least 0.2 weight % and up to and including 50 weight % based on the total weight of the (c) surface treated titanium dioxide or zinc oxide particles that scatter visible light, wherein the amounts of the (a), (b), and (c) components are based on the total weight of the aqueous composition, to provide an inkjet receiving media having an opacity of at least 50% and a color difference defined by an a* value of at least -5 and at most and including +5 and a b* value of at least -5 and at most and including +5, the topcoat composition on the at least one surface having a dry solid coating weight of at least 0.1 g / m 2 and at most and including 10 g / m 2 2. The inkjet receiving media of claim 1, wherein the topcoat composition has a dry solid coating weight of at least 0.1 g / m2and at most and including 10 g / m2. wherein the substrate is a transparent or metallized polymeric film.

23. The method of claim 22, wherein the substrate is a transparent biaxially oriented polyethylene terephthalate (BOPET) film, an aluminum metallized BOPET (m-BOPET) film, or a biaxially oriented polypropylene (BOPP) film.

24. The method of claim 22 or 23, comprising disposing the aqueous composition on the substrate surface in-line after the substrate is prepared.

25. The method of claim 22 or 23, wherein the topcoat composition has a dry solid coating weight of at least 0.2 g / m 2 and up to and including 2 g / m 2 of dry solid coating weight.

26. The method of claim 22 or 23, wherein the substrate has an L* value of 50 or less.

27. The method of claim 22 or 23, wherein the aqueous composition further comprises: (d) particles different from the (c) component, the (d) particles having a Rockwell hardness less than or equal to R90, and present in an amount of at least 0.02 weight % and up to and including 5 weight % based on the total weight of the aqueous composition.

28. The method of claim 22 or 23, wherein the aqueous composition further comprises: (e) a cross-linkable polymeric material different from all of the (a), (b), and (c) components, and present in an amount of at least 0.1 weight % and up to and including 30 weight % based on the total weight of the aqueous composition.

29. The method of claim 22 or 23, wherein the (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder materials comprise at least polyvinyl alcohol, polyethylene imine, polyethylene oxide, polyvinyl amine, a copolymer derived at least in part from ethylene alcohol and ethylene oxide, a copolymer derived at least in part from ethylene amine and ethylene alcohol, or a combination of two or more of these materials.

30. The method of claim 22, wherein the (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder materials are the same as the (f) dispersion aid.

31. A method for inkjet printing, comprising in order: A) providing an inkjet receiving medium comprising a substrate and a topcoat composition disposed on a surface thereof, the topcoat composition comprising the following (a), (b), (c), and (f) components: (a) water soluble salts of one or more polyvalent metal cations, said (a) one or more water soluble salts being present in an amount of at least 0.4 wt% and up to and including 40 wt%; (b) one or more non-ionic or cationic water soluble or water dispersible polymeric binder materials, present in an amount of at least 0.5 wt% and up to and including 90 wt%; (c) surface treated visible light scattering titanium dioxide or zinc oxide particles that have been surface treated with one or more (f) dispersing aids, and present in an amount of at least 6 wt% and up to and including 90 wt%; and (f) dispersing aids for said (c) surface treated visible light scattering titanium dioxide or zinc oxide particles, said (f) dispersing aids being cationic on a cumulative charge basis, and present in said topcoat composition in an amount of at least 0.2 wt% and up to and including 50 wt% based on the total weight of said (c) surface treated visible light scattering titanium dioxide or zinc oxide particles, wherein the amounts of said (a), (b) and (c) components are based on the total weight of the topcoat composition; and B) inkjet printing one or more aqueous pigment-based inks onto said topcoat composition to provide a pigment-based image or layer, wherein said substrate is a transparent or metallized polymeric film.

32. The method of claim 31, further comprising: C) applying an aqueous colorless ink composition to said pigment-based image or layer.

33. The method of claim 31 or 32, comprising printing one or more aqueous pigment-based inks onto said topcoat composition disposed as a pattern on the surface of the substrate using an inkjet deposition system to provide a pigment-based image that is in registration with the pattern of the topcoat composition.

34. The method of claim 31 or 32, wherein said one or more aqueous pigment-based inks are each supplied as one or more continuous streams from a respective main fluid supply, said one or more continuous streams each being split into both printing drops and non-printing drops; and collecting the non-printing drops from each of said one or more continuous streams and returning them to the respective main fluid supply.

35. The method of claim 31 or 32, comprising disposing said topcoat composition on the surface of the substrate in a pattern using flexographic printing, and said B) inkjet printing one or more aqueous pigment-based inks onto the pattern of the topcoat composition provides a pigment-based image that is in registration with the pattern of the topcoat composition.

36. The method of claim 31 or 32, comprising disposing said topcoat composition on the surface of the substrate, and conducting said B) inkjet printing in-line at different stations of a multi-station apparatus.

37. The method of claim 31 or 32, wherein said substrate is a transparent biaxially oriented polyethylene terephthalate (BOPET) film, an aluminum metallized BOPET (m-BOPET) film, or a biaxially oriented polypropylene (BOPP) film.

38. The method of claim 31 or 32, wherein the topcoat composition has a dry solid coating weight of at least 0.1 g / m 2 and up to and including 2 g / m 2 2.

39. The method of claim 31 or 32, wherein said topcoat composition further comprises: (d) particles different from the (c) component, the (d) particles having a Rockwell hardness less than or equal to R90, and present in an amount of at least 0.06 wt% and up to and including 10 wt%, based on the total weight of the topcoat composition.

40. The method of claim 31 or 32, wherein the topcoat composition further comprises: (e) a cross-linkable polymeric material different from all of the (a), (b), and (c) components, and present in an amount of at least 0.1 wt% and up to and including 30 wt%, based on the total weight of the topcoat composition.

41. The method of claim 31 or 32, wherein the (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder materials comprises at least polyvinyl alcohol, polyethyleneimine, polyethylene oxide, polyvinylamine, a copolymer derived at least in part from ethylene alcohol and ethylene oxide, a copolymer derived at least in part from ethylene amine and ethylene alcohol, or a combination of two or more of these materials.

42. The method of claim 41, wherein the (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder materials comprises at least polyvinylamine, polyethyleneimine, polyvinyl alcohol, or a copolymer derived at least from ethylene amine and ethylene alcohol, and the (f) dispersion aid comprises at least a protonated polyethyleneimine or a protonated polyvinylamine.

43. A method for providing an inkjet printed article, comprising in order: A’) providing a substrate having a surface, A”) providing an inkjet receiving medium by disposing an aqueous composition onto the surface of the substrate to form a topcoat composition, the aqueous composition having at least 2% solids and up to and including 90% solids, and the aqueous composition comprising the following (a), (b), (c), and (f) components: (a) water-soluble salts of one or more polyvalent metal cations, the (a) one or more water-soluble salts being present in an amount of at least 0.5 wt% and up to and including 30 wt%; (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder materials, present in an amount of at least 0.1 wt% and up to and including 30 wt%; (c) surface-treated visible light-scattering titania or zinc oxide particles, which have been surface-treated using one or more (f) dispersion aids, such that the aqueous composition has a stable zeta potential greater than +10 millivolts, and which are present in an amount of at least 5 wt% and up to and including 60 wt%; and (f) a dispersion aid for the (c) surface-treated visible light-scattering titania or zinc oxide particles, the (f) dispersion aid being cationic on a cumulative charge basis, and present in the topcoat composition in an amount of at least 0.2 wt% and up to and including 50 wt%, based on the total weight of the (c) surface-treated visible light-scattering titania or zinc oxide particles, wherein the amounts of the (a), (b), and (c) components are based on the total weight of the aqueous composition; and A”) providing an inkjet receiving medium by disposing an aqueous composition onto the surface of the substrate to form a topcoat composition, the aqueous composition having at least 2% solids and up to and including 90% solids, and the aqueous composition comprising the following (a), (b), (c), and (f) components: (a) water-soluble salts of one or more polyvalent metal cations, the (a) one or more water-soluble salts being present in an amount of at least 0.5 wt% and up to and including 30 wt%; (b) one or more non-ionic or cationic water-soluble or water-dispersible polymeric binder materials, present in an amount of at least 0.1 wt% and up to and including 30 wt%; (c) surface-treated visible light-scattering titania or zinc oxide particles, which have been surface-treated using one or more (f) dispersion aids, such that the aqueous composition has a stable zeta potential greater than +10 millivolts, and which are present in an amount of at least 5 wt% and up to and including 60 wt%; and (f) a dispersion aid for the (c) surface-treated visible light-scattering titania or zinc oxide particles, the (f) dispersion aid being cationic on a cumulative charge basis, and present in the topcoat composition in an amount of at least 0.2 wt% and up to and including 50 wt%, based on the total weight of the (c) surface-treated visible light-scattering titania or zinc oxide particles, wherein the amounts of the (a), (b), and (c) components are based on the total weight of the aqueous composition; B) inkjet printing one or more aqueous pigment-based inks onto the topcoat composition to provide a pigment-based image or layer, wherein the substrate is a transparent or metallized polymeric film.

44. The method of claim 43, wherein the substrate is a transparent biaxially oriented polyethylene terephthalate (BOPET) film, an aluminum metallized BOPET (m-BOPET) film, or a biaxially oriented polypropylene (BOPP) film.

45. An inkjet printed article comprising: a substrate comprising a surface; a topcoat composition disposed on the substrate surface, the topcoat composition comprising the following (a), (b), (c), and (f) components: (a) one or more water soluble salts of polyvalent metal cations, the (a) one or more water soluble salts being present in an amount of at least 0.4 weight % and up to and including 40 weight %; (b) one or more non-ionic or cationic water soluble or water dispersible polymeric binder materials, present in an amount of at least 2 weight % and up to and including 90 weight %; (c) surface treated visible light scattering titanium dioxide or zinc oxide particles that have been surface treated using one or more (f) dispersion aids, and present in an amount of at least 6 weight % and up to and including 90 weight %; and (f) dispersion aids for the (c) surface treated visible light scattering titanium dioxide or zinc oxide particles, the (f) dispersion aids being cationic on a cumulative charge basis, and present in the topcoat composition in an amount of at least 0.2 weight % and up to and including 50 weight % based on the total weight of the (c) surface treated visible light scattering titanium dioxide or zinc oxide particles, wherein the amounts of the (a), (b), and (c) components are based on the total weight of the topcoat composition; and a pigment-based inkjet printed layer or image disposed over the topcoat composition, wherein the substrate is a transparent or metallized polymeric film.

46. The inkjet printed article of claim 45, wherein the topcoat composition has a dry solid coating weight of at least 0.1 g / m 2 and up to and including 10 g / m 2 .

47. The inkjet printed article of claim 45 or 46, wherein the topcoat composition is disposed on the substrate surface as a pattern, and the pigment-based inkjet printed image is arranged in registration with the pattern of the topcoat composition.

48. The inkjet printed article of claim 45 or 46, wherein a water-based colorless ink composition is disposed on the pigment-based inkjet printed layer or image.

49. The inkjet printed article of claim 45 or 46, wherein the substrate is a transparent biaxially oriented polyethylene terephthalate (BOPET) film, an aluminum metallized BOPET (m-BOPET) film, or a biaxially oriented polypropylene (BOPP) film.

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