阅读说明：本技术 静电墨水组合物 (Electrostatic ink composition ) 是由 K·高德斯坦 G·巴-海姆 D·萨维尔森 T·罗森塔尔 I·艾尔 R·阿维格多 于 2019-09-27 设计创作，主要内容包括：在本文中描述了一种黄色液体电子照相墨水组合物,其包含：包含具有酸性侧基的聚合物的热塑性树脂；和包含黄色颜料的着色剂,其中所述黄色颜料包含腙化合物。在本文中也描述了一种使用黄色液体电子照相墨水组合物生产经印刷的基底的方法和由其制成的经印刷的基底。(Described herein is a yellow liquid electrophotographic ink composition comprising: a thermoplastic resin comprising a polymer having acidic side groups; and a colorant comprising a yellow pigment, wherein the yellow pigment comprises a hydrazone compound. Also described herein is a method of producing a printed substrate using the yellow liquid electrophotographic ink composition and a printed substrate made therefrom.)

1. A yellow liquid electrophotographic ink composition comprising:

a thermoplastic resin comprising a polymer having acidic side groups; and

a colorant comprising a yellow pigment, wherein the yellow pigment comprises a hydrazone compound.

2. The yellow liquid electrophotographic ink composition of claim 1, wherein the yellow pigment consists of a hydrazone compound.

3. The yellow liquid electrophotographic ink composition of claim 1, wherein the yellow pigment comprises a hydrazone compound of formula Ia:

formula Ia

Wherein R is¹To R⁶Each independently selected from a hydrogen atom, a C1 to C3 alkyl group, a C1 to C3 alkoxy group, a nitro group, and a halogen group.

4. The yellow liquid electrophotographic ink composition according to claim 3, wherein R¹To R³At least one of (a) is a nitro group.

5. The yellow liquid electrophotographic ink composition of claim 4, wherein the nitro group is para to the hydrazone group.

6. The yellow liquid electrophotographic ink composition according to claim 3, wherein R¹To R⁶At least one of (a) is methoxy.

7. The yellow liquid electrophotographic ink composition according to claim 6, wherein R¹To R³At least one of (a) is a nitro group.

8. The yellow liquid electrophotographic ink composition of claim 1, wherein the yellow pigment comprises a hydrazone compound of formula II:

formula II.

9. The yellow liquid electrophotographic ink composition according to claim 1, wherein the colorant is present in an amount up to about 30% by weight of the non-volatile solids of the yellow liquid electrophotographic ink composition.

10. The yellow liquid electrophotographic ink composition according to claim 1, wherein the colorant is present in an amount from about 15% to about 35% by weight of the non-volatile solids of the yellow liquid electrophotographic ink composition.

11. The yellow liquid electrophotographic ink composition of claim 1, wherein the polymer having acidic side groups is a copolymer of an olefin monomer and a monomer selected from acrylic acid and methacrylic acid.

12. The yellow liquid electrophotographic ink composition of claim 1, wherein the yellow pigment consists of a hydrazone compound of formula II

Formula II.

13. A printed substrate comprising

A substrate; and

an ink composition for yellow liquid electrophotographic printing disposed thereon; wherein the yellow liquid electrophotographic printing ink composition comprises:

a thermoplastic resin comprising a polymer having acidic side groups; and

a colorant comprising a yellow pigment, wherein the yellow pigment comprises a hydrazone compound.

14. A printed substrate according to claim 13, wherein the colorant comprises a hydrazone compound of formula Ia:

formula Ia

Wherein R is¹To R⁶Each independently selected from a hydrogen atom, a C1 to C3 alkyl group, a C1 to C3 alkoxy group, a nitro group, and a halogen group.

15. A method of producing a printed substrate comprising:

applying a yellow liquid electrophotographic ink composition to a substrate with a liquid electrophotographic printer;

wherein the yellow liquid electrophotographic ink composition comprises:

a thermoplastic resin comprising a polymer having acidic side groups; and

a colorant comprising a yellow pigment, wherein the yellow pigment comprises a hydrazone compound.

Background

Electrophotographic printing processes, sometimes referred to as xerographic processes, typically involve producing an image on a photoconductive surface, applying an ink having charged particles to the photoconductive surface to selectively bind them to the image, and then transferring the charged particles in the form of the image to a print substrate.

The photoconductive surface may be on a cylinder and is commonly referred to as a Photo Imaging Plate (PIP). The photoconductive surface is selectively charged with an electrostatic latent image having image areas and background areas of different potentials. For example, an electrostatic ink composition comprising charged particles in a liquid carrier may be contacted with a selectively charged photoconductive surface. The charged particles adhere to the image areas of the latent image while the background areas remain clean. The image is then transferred directly to a print substrate (e.g., a polymeric substrate) or first to an intermediate transfer member (which may be a soft, intumescent blanket), which is typically heated to fuse the solid image and evaporate the liquid carrier, and then transferred to the print substrate.

The ink set used for printing may be based on a CMYK color model with four inks (cyan, magenta, yellow and key/black), although multiple imprints (multiple imprints) of a particular ink may have to be printed in order to achieve a particular pantone color number within the color gamut of a particular ink set.

Brief Description of Drawings

FIG. 1 is a graph showing the comparative example 1 and example liquid electrophotographic ink compositions (20 wt% particle loading, Sunbrite 2725157 as pigment yellow 74) on a) coated paper (Condat 300 g/m)²) And b) chart of release performance on uncoated paper (Soperset).

Detailed description of the invention

Before the present disclosure is disclosed and described, it is to be understood that this disclosure is not limited to the particular process steps and materials disclosed herein as such process steps and materials may vary. It is also to be understood that the terminology used herein is used for the purpose of describing particular embodiments. The terms are not intended to be limiting since the scope is intended to be limited by the appended claims and equivalents thereof.

It is noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

As used herein, "carrier fluid", "carrier liquid", "carrier" or "carrier vehicle" refers to a fluid in which pigment particles, resins, charge directors, and other additives may be dispersed to form a liquid electrostatic ink composition or a liquid electrophotographic ink composition. The carrier liquid may include a mixture of various agents, such as surfactants, co-solvents, viscosity modifiers, and/or other possible ingredients.

As used herein, "liquid electrostatic ink composition" or "liquid electrophotographic composition" generally refers to an ink composition that is generally suitable for use in an electrostatic printing process (sometimes referred to as an electrophotographic printing process). Which may comprise pigment particles having a thermoplastic resin thereon. The electrostatic ink composition may be a liquid electrostatic ink composition in which pigment particles having a resin thereon are suspended in a carrier liquid. The pigment particles having the resin thereon are generally charged or capable of forming a charge in an electric field to cause them to exhibit electrophoretic behavior. A charge director may be present to impart a charge to the pigment particles having the resin thereon.

As used herein, "copolymer" refers to a polymer polymerized from at least two monomers. However, a particular list of copolymers of monomer types (e.g., copolymers of monomer a and monomer B) refers to copolymers polymerized from these types of monomers and without other types of monomers (e.g., AB polymers).

As used herein, the Total Base Number (TBN), sometimes referred to simply as base number, can be determined using standard techniques, including those set forth in ASTM Designation D4739-08, such as Test Method D2896, Test Method D4739, and ASTM Designation D974-08, using Test Method D2896 if any inconsistency is exhibited between Test methods, and unless otherwise indicated, the Test Method or methods are the most recently disclosed at the time of filing this patent application. "mgKOH/g material" means "mgKOH/g dispersant". Measurement of TBN of dispersantIt is possible to use pure dispersants, or dispersants in water or hydrocarbon liquids, such as in white spirit (white spirit), for example dearomatized white spirit, mineral oil or distillates (for example C)_10-20Hydrocarbon) and then adjusted as measured for the pure dispersant.

As used herein, "melt flow rate" generally refers to the extrusion rate at which a resin is extruded through an orifice of a specified size at a specified temperature and load (typically reported as temperature/load, e.g., 190 ℃/2.16 kg). The flow rate can be used to grade or provide a measure of material degradation caused by molding. In the present disclosure, unless otherwise indicated, "Melt Flow rate" is measured according to ASTM D1238 Standard Test Method for Melt Flow Rates of Thermoplastics by Extrusion Plastometer as known in the art. If the melt flow rate of a particular polymer is specified, it is the melt flow rate of the polymer itself in the absence of any other component of the liquid electrostatic ink composition, unless otherwise specified.

As used herein, "acidity", "acid number" or "acid value" refers to the mass of potassium hydroxide (KOH) in milligrams that neutralizes 1 gram of material. The acidity of the polymer can be measured according to standard techniques such as those described in ASTM D1386. If the acidity of a particular polymer is specified, it is the acidity of the polymer itself in the absence of any other component of the liquid toner composition, unless otherwise specified.

As used herein, "melt viscosity" generally refers to the ratio of shear stress to shear rate at a given shear stress or shear rate. Testing is typically performed using a capillary rheometer. The plastic charge was heated in the rheometer barrel and pushed through the die with a plunger. Depending on the equipment, the plunger is pushed with a constant force or at a constant rate. Once the system reaches steady state operation, measurements are taken. As known in the art, one method used is to measure brookfield viscosity @ 140 ℃ in units of mPa ∙ s or cPoise. Alternatively, a rheometer, such as the commercially available AR-2000 rheometer from Thermal Analysis Instruments, can be used, using geometry: 25 mm steel plate-standard steel parallel plate and obtaining plate-to-plate (plate over plate) rheological isotherm measurement melt viscosity at 120 ℃ and 0.01 Hz shear rate. If the melt viscosity of a particular polymer is specified, it is the melt viscosity of the polymer itself in the absence of any other component of the electrostatic composition, unless otherwise specified.

A certain monomer may be described herein as a particular weight percentage of the constituent polymer. This means that the repeating units formed from the monomers in the polymer constitute said weight percentage of the polymer.

If reference is made herein to a standard test, unless otherwise indicated, the test version to be referred to is the most recent version at the time of filing the present patent application.

As used herein, "liquid electrostatic printing" or "liquid electrophotographic printing" generally refers to a process that provides an image that is transferred from a photoimageable substrate or plate, either directly or indirectly via an intermediate transfer member, to a printing substrate, such as a polymeric substrate. Thus, the image is not substantially absorbed into the photoimageable substrate to which it is applied. In addition, "liquid electrophotographic printer" or "liquid electrostatic printer" generally refers to a printer capable of performing electrophotographic printing or electrostatic printing as described above. The Liquid Electrophotographic (LEP) printing process may involve applying an electric field to the liquid electrophotographic ink composition, for example, an electric field having a field gradient of 50-400V/μm or more, in some examples 600-900V/μm or more, in some examples 1000V/cm or more, in some examples 1000V/mm or more.

As used herein, "LEP image" or "printed LEP image" refers to an image that has been printed, for example, on a print substrate by liquid electrophotographic printing of the LEP ink composition described herein.

As used herein, "NVS" is an abbreviation for the term "non-volatile solid".

The term "about" is used herein to provide flexibility to the end points of a numerical range, where a given value may be slightly above or below the end point to account for variations in the test method or apparatus. The degree of flexibility of this term can depend on the particular variable and is within the knowledge of one skilled in the art to determine based on experience and the associated description herein.

As used herein, a plurality of items, structural elements, compositional elements, and/or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary.

Concentrations, amounts, and other numerical data may be expressed or presented herein in a range format. It is to be understood that such a range format is used merely for convenience and brevity and thus should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a numerical range of "about 1 wt% to about 5 wt%" should be interpreted to include not only the explicitly recited values of about 1 wt% to about 5 wt%, but also include individual values and sub-ranges within the indicated range. Accordingly, included in this numerical range are individual values, e.g., 2, 3.5, and 4, and sub-ranges, e.g., 1-3, 2-4, and 3-5, etc. This principle applies equally to ranges reciting a single numerical value. Moreover, such an interpretation applies regardless of the breadth of the range or the characteristics being described.

As used herein, unless otherwise indicated, a wt% value shall be taken to mean the weight-weight (w/w) percentage of solids in the ink composition, and not include the weight of any carrier fluid present.

Any feature described herein may be combined with any aspect or any other feature described herein, unless otherwise specified.

In one aspect, there is provided a yellow liquid electrophotographic ink composition comprising:

a thermoplastic resin comprising a polymer having acidic side groups; and

a colorant comprising a yellow pigment, wherein the yellow pigment comprises a hydrazone compound.

In another aspect, there is provided a printed substrate comprising:

a substrate; and

a yellow liquid electrophotographic print image disposed thereon; wherein the yellow liquid electrophotographic printing ink composition comprises:

a thermoplastic resin comprising a polymer having acidic side groups; and

a colorant comprising a yellow pigment, wherein the yellow pigment comprises a hydrazone compound.

In a further aspect, there is provided a method of producing a printed substrate comprising:

applying a yellow liquid electrophotographic ink composition to a substrate with a liquid electrophotographic printer;

wherein the yellow liquid electrophotographic ink composition comprises:

a thermoplastic resin comprising a polymer having acidic side groups; and

a colorant comprising a yellow pigment, wherein the yellow pigment comprises a hydrazone compound.

The yellow liquid electrophotographic ink composition comprises a yellow pigment containing an isoindoline compound, such as pigment yellow 185 and pigment yellow 139. When printed with cyan, magenta, and black/accent color liquid electrophotographic ink compositions (CMYK printing), these pigments fail to achieve full gamut. Yellow liquid electrophotographic ink compositions based on hydrazone compounds have been found to improve the chroma and lightness of the ink. In addition, the transfer of a liquid electrophotographic ink composition comprising a yellow pigment comprising a hydrazone compound from an intermediate transfer member of a liquid electrostatic printer to a substrate is improved, particularly at the higher pigment loadings achievable with liquid electrophotographic ink compositions comprising yellow pigments comprising isoindoline compounds. In addition, the peel resistance of the yellow liquid electrophotographic printing ink composition is also improved. Thus, a smaller amount of yellow liquid electrophotographic ink composition comprising a hydrazine compound can be used to provide a particular optical density.

Yellow liquid electrophotographic ink composition

A yellow Liquid Electrophotographic (LEP) ink composition may comprise: a thermoplastic resin comprising a polymer having acidic side groups; and a colorant comprising a yellow pigment, wherein the yellow pigment comprises a hydrazone compound.

In some examples, the yellow LEP ink composition may comprise: a liquid carrier; a thermoplastic resin comprising a polymer having acidic side groups; and a colorant comprising a yellow pigment, wherein the yellow pigment comprises a hydrazone compound. The yellow LEP ink composition can include a liquid carrier and chargeable particles suspended in the liquid carrier, the chargeable particles including a thermoplastic resin and a colorant. The chargeable particles may comprise: a thermoplastic resin comprising a polymer having acidic side groups and a colorant comprising a yellow pigment, wherein the yellow pigment comprises a hydrazone compound.

In some examples, the yellow LEP ink composition further comprises a dispersant. In some examples, the yellow LEP ink composition may comprise: a thermoplastic resin comprising a polymer having acidic side groups; a colorant comprising a yellow pigment, wherein the yellow pigment comprises a hydrazone compound; and a dispersant. In some examples, the yellow LEP ink composition comprises: a thermoplastic resin comprising a polymer having acidic side groups; a colorant comprising a yellow pigment, wherein the yellow pigment comprises a hydrazone compound; a dispersant; and a liquid carrier.

In some examples, the yellow LEP ink composition may further comprise a charge director. In some examples, the yellow LEP ink composition may comprise a thermoplastic resin; a colorant and a charge director. In some examples, the yellow LEP ink composition may comprise a thermoplastic resin; a colorant, a dispersant; and a charge director. In some examples, the yellow LEP ink composition may include a thermoplastic resin, a colorant, a liquid carrier, and a charge director. In some examples, the yellow LEP ink composition may comprise a thermoplastic resin; a colorant; a liquid carrier; a dispersant; and a charge director.

In some examples, the yellow LEP ink composition may further comprise a charge adjuvant. In some examples, the yellow LEP ink composition may comprise a thermoplastic resin; a colorant and a charge adjuvant. In some examples, the yellow LEP ink composition may comprise a thermoplastic resin; a colorant; a dispersant; and a charge adjuvant. In some examples, the yellow LEP ink composition can include a thermoplastic resin, a colorant, a charge adjuvant, and a liquid carrier. In some examples, the yellow LEP ink composition may include a thermoplastic resin, a colorant, a charge adjuvant, a liquid carrier, and a dispersant. In some examples, the yellow LEP ink composition may include a thermoplastic resin, a colorant, a charge adjuvant, and a charge director. In some examples, the yellow LEP ink composition may comprise a thermoplastic resin; a colorant; a dispersant; charge adjuvants and charge directors. In some examples, the yellow LEP ink composition can include a thermoplastic resin, a colorant, a charge adjuvant, a charge director, and a liquid carrier. In some examples, the yellow LEP ink composition can include a thermoplastic resin, a colorant, a charge adjuvant, a charge director, a dispersant, and a liquid carrier.

In some examples, the yellow LEP ink composition may further comprise an additive.

Coloring agent

The colorant comprises a yellow pigment, wherein the yellow pigment comprises a hydrazone compound. In some examples, the yellow pigment consists of a hydrazone compound. As used herein, a hydrazone compound is a compound containing at least one hydrazone group.

Hydrazone groups

Pigments comprising hydrazone groups were previously considered to comprise tautomeric forms, i.e. these pigments are considered to be azo compounds:

azo forms

In some examples, the yellow pigment comprises a hydrazone compound of formula I:

formula I

Wherein Ar and Ar ʹ are substituted or unsubstituted aryl groups. In some examples, Ar and Ar ʹ may be the same or different. In some examples, Ar and Ar ʹ may be substituted aryl groups, wherein the substituents are independently selected from C1 to C3 alkyl, C1 to C3 alkoxy, nitro, and halo. In some examples, the aryl group can be a substituted or unsubstituted C5 to C8 aryl group, such as a substituted or unsubstituted benzyl ring.

In some examples, the yellow pigment comprises a hydrazone compound of formula Ia:

formula Ia

Wherein R is¹To R⁶Each independently selected from a hydrogen atom, a C1 to C3 alkyl group, a C1 to C3 alkoxy group, a nitro group, and a halogen group.

In some examples, R¹To R³At least one of (a) is a nitro group. In some examples, the nitro group is para to the hydrazone group.

In some examples, R¹To R⁶Is a C1 to C3 alkoxy group, for example methoxy. In some examples, R¹To R⁶One is a C1 to C3 alkoxy group, such as methoxy. In some examples, R¹To R³Is a C1 to C3 alkoxy group, for example methoxy. In some examples, R¹To R³One is a C1 to C3 alkoxy group, such as methoxy. In some examples, R⁴To R⁶Is a C1 to C3 alkoxy group, for example methoxy. In some examples, R⁴To R⁶One is a C1 to C3 alkoxy group, such as methoxy. In some examples, R⁴To R⁶Are independently C1 to C3 alkoxy, e.g. methoxy.

In some examples, R¹To R³At least one of (A) is C1 to C3 alkoxy, e.g. methoxy, and R⁴To R⁶Is a C1 to C3 alkoxy group, for example methoxy. In some examples, R¹To R³One is C1 to C3 alkoxy, e.g. methoxy, and R⁴To R⁶One is a C1 to C3 alkoxy group, such as methoxy.

In some examples, R¹To R³At least one of (A) is nitro and R is¹To R⁶Is a C1 to C3 alkoxy group, for example methoxy. In some examples, R¹To R³At least one of (A) is nitro and R is¹To R⁶One is a C1 to C3 alkoxy group, such as methoxy. In some examples, R¹To R³At least one of (A) is nitro and R is¹To R³Is a C1 to C3 alkoxy group, for example methoxy. In some examples, R¹To R³At least one of (A) is nitro and R is¹To R³One is a C1 to C3 alkoxy group, such as methoxy. In some examples, R¹To R³At least one of (A) is nitro and R is⁴To R⁶Is a C1 to C3 alkoxy group, for example methoxy. In some examples, R¹To R³At least one of (A) is nitro and R is⁴To R⁶One is a C1 to C3 alkoxy group, such as methoxy. In some examples, R¹To R³At least one of (A) is nitro and R is⁴To R⁶Are independently C1 to C3 alkoxy, e.g. methoxy. In some examples, R¹To R³At least one of (A) is nitro and R is¹To R³At least one of (A) is C1 to C3 alkoxy, e.g. methoxy, and R⁴To R⁶Is a C1 to C3 alkoxy group, for example methoxy. In some examples, R¹To R³At least one of (A) is nitro and R is¹To R³One is C1 to C3 alkoxy, e.g. methoxy and R⁴To R⁶One is a C1 to C3 alkoxy group, such as methoxy.

In some examples, the yellow pigment comprises a hydrazone compound of formula Ib:

formula Ib

Wherein R is¹And R³To R⁶Each independently selected from a hydrogen atom, a C1 to C3 alkyl group, a C1 to C3 alkoxy group, a nitro group, and a halogen group. In some examples, the yellow pigment comprises a hydrazone compound of formula Ib and R¹And R³To R⁶Independently selected from a hydrogen atom, a C1 to C3 alkoxy group (e.g. methoxy), and a halogen group (e.g. chloro). In some examples, the yellow pigment comprises a hydrazone compound of formula Ib and R¹And R³At least one of (A) is C1 to C3 alkoxy (e.g. methoxy) and R⁴To R⁶Is a C1 to C3 alkoxy group (e.g., methoxy).

In some examples, the yellow pigment comprises a hydrazone compound selected from formula II:

formula II

In some examples, the yellow pigment consists of a hydrazone compound of formula II.

In some examples, the yellow pigment is pigment yellow 74.

In some examples, the yellow liquid electrophotographic ink composition includes a colorant in an amount of up to about 40% by weight of the non-volatile solids of the yellow liquid electrophotographic ink composition, such as about 35% by weight or less, about 30% by weight or less, about 29% by weight or less, about 28% by weight or less, about 27% by weight or less, about 26% by weight or less, about 25% by weight or less, about 24% by weight or less, about 23% by weight or less, about 22% by weight or less, about 21% by weight or less, about 20% by weight or less, about 15% by weight or less, or about 10% by weight or less of the non-volatile solids of the liquid electrophotographic ink composition. In some examples, the yellow liquid electrophotographic ink composition comprises colorant in an amount of about 10% by weight or more of the non-volatile solids of the yellow liquid electrophotographic ink composition, such as about 15% by weight or more, about 20% by weight or more, about 21% by weight or more, about 22% by weight or more, about 23% by weight or more, about 24% by weight or more, about 25% by weight or more, about 26% by weight or more, about 27% by weight or more, about 28% by weight or more, about 29% by weight or more, about 30% by weight or more, about 35% by weight or more, or about 40% by weight or more. In some examples, the yellow liquid electrophotographic ink composition includes a colorant in an amount from about 10% to about 40% by weight of the non-volatile solids of the liquid electrophotographic ink composition, such as from about 15% to about 35%, from about 20% to about 30%, from about 21% to about 29%, from about 22% to about 28%, from about 23% to about 27%, from about 24% to about 26%, or from about 25% to about 30% by weight of the non-volatile solids of the liquid electrophotographic ink composition.

In some examples, the colorant may comprise a yellow pigment and a resin, such as a thermoplastic resin. In some examples, the colorant may comprise a yellow pigment, a resin, and an additive. In some examples, the colorant may consist of a yellow pigment.

In some examples, the colorant comprises at least 50 wt% yellow pigment, such as at least 60 wt%, at least 65 wt%, at least 70 wt%, at least 75 wt%, at least 80 wt%, at least 85 wt%, at least 90 wt%, at least 91 wt%, at least 92 wt%, at least 93 wt%, at least 94 wt%, at least 95 wt%, at least 96 wt%, at least 97 wt%, at least 98 wt%, at least 99 wt%, at least 99.5 wt%, or at least 99.9 wt% yellow pigment. In some examples, the colorant comprises 99.9 wt% or less of a yellow pigment, such as 99.5 wt% or less, 99 wt% or less, 98 wt% or less, 97 wt% or less, 96 wt% or less, 95 wt% or less, 94 wt% or less, 93 wt% or less, 92 wt% or less, 91 wt% or less, 90 wt% or less, 95 wt% or less, 90 wt% or less, 85 wt% or less, 80 wt% or less, 75 wt% or less, 70 wt% or less, 65 wt% or less, 60 wt% or less, or 50 wt% or less of a yellow pigment. In some examples, the colorant comprises 50 to 99.9 wt% yellow pigment, such as 60 to 99.5 wt%, 65 to 99 wt%, 70 to 98 wt%, 75 to 97 wt%, 80 to 96 wt%, 85 to 95 wt%, 90 to 94 wt%, 91 to 93 wt%, or 92 to 99 wt% yellow pigment.

In some examples, the yellow pigment is pigment yellow 74. In some examples, pigment yellow 74 is Ink jet GX-W (available from Clariant), Toner GX (available from Clariant), Sunbrite 2725147 (available from Sun Chemical), or Sunbrite 2725157 (available from Sun Chemical). Other sources of pigment yellow 74 include Rex-ton, Heubach, Sanyo Color, and Sudarshan (India).

Thermoplastic resin

The yellow liquid electrophotographic ink composition includes a thermoplastic resin. In some examples, the thermoplastic resin comprises a polymer having acidic side groups. The thermoplastic resin may be referred to herein as a resin.

In some examples, the yellow LEP ink composition comprises chargeable particles (i.e., having a charge or capable of forming a charge, e.g., in an electromagnetic field) comprising a thermoplastic resin and, in some examples, a colorant.

In some examples, the thermoplastic resin may comprise a thermoplastic resin selected from ethylene acrylic acid copolymers; ethylene methacrylic acid copolymers; ethylene vinyl acetate copolymers; copolymers of ethylene (e.g., 80 to 99.9 wt.%) and alkyl (e.g., C1 to C5) esters of methacrylic or acrylic acid (e.g., 0.1 to 20 wt.%); copolymers of ethylene (e.g., 80 to 99.9 wt%), acrylic acid or methacrylic acid (e.g., 0.1 to 20.0 wt%), and alkyl (e.g., C1 to C5) esters of methacrylic acid or acrylic acid (e.g., 0.1 to 20 wt%); polyethylene; polystyrene; isotactic polypropylene (crystalline); ethylene ethyl acrylate; a polyester; polyvinyl toluene; a polyamide; styrene/butadiene copolymers; an epoxy resin; acrylic resins (e.g., copolymers of acrylic or methacrylic acid and at least one alkyl acrylate or methacrylate, wherein the alkyl group is in some examples 1 to about 20 carbon atoms, such as methyl methacrylate (e.g., 50 to 90 wt%)/methacrylic acid (e.g., 0 to 20 wt%)/ethylhexyl acrylate (e.g., 10 to 50 wt%)); ethylene-acrylate terpolymers; ethylene-acrylate-Maleic Anhydride (MAH) or Glycidyl Methacrylate (GMA) terpolymers; ethylene-acrylic acid ionomers and combinations thereof.

The polymer having acidic side groups may have an acidity of 50 mg KOH/g or more, in some examples 60 mg KOH/g or more, in some examples 70 mg KOH/g or more, in some examples 80 mg KOH/g or more, in some examples 90 mg KOH/g or more, in some examples 100 mg KOH/g or more, in some examples 105 mg KOH/g or more, in some examples 110 mg KOH/g or more, in some examples 115 mg KOH/g or more. The polymer having acidic side groups may have an acidity of 200 mg KOH/g or less, in some examples 190 mg KOH/g or less, in some examples 180 mg KOH/g or less, in some examples 130 mg KOH/g or less, in some examples 120 mg KOH/g or less. Polymer acidity in mg KOH/g can be measured using standard procedures known in the art, for example using the procedure described in ASTM D1386.

The thermoplastic resin may comprise a polymer having acidic side groups that has a melt flow rate of less than about 60 grams/10 minutes, in some examples about 50 grams/10 minutes or less, in some examples about 40 grams/10 minutes or less, in some examples 30 grams/10 minutes or less, in some examples 20 grams/10 minutes or less, in some examples 10 grams/10 minutes or less. In some examples, all polymers having acidic side groups and/or ester groups in the particles each independently have a melt flow rate of less than 90 grams/10 minutes, 80 grams/10 minutes or less, in some examples 70 grams/10 minutes or less, in some examples 60 grams/10 minutes or less.

The polymer having acidic side groups may have a melt flow rate of from about 10 g/10 min to about 120 g/10 min, in some examples from about 10 g/10 min to about 70 g/10 min, in some examples from about 10 g/10 min to 40 g/10 min, in some examples from 20 g/10 min to 30 g/10 min. The polymer having acidic side groups can have a melt flow rate of from about 50 g/10 min to about 120 g/10 min in some examples, and from 60 g/10 min to about 100 g/10 min in some examples. Melt flow rate can be measured using standard procedures known in the art, for example as described in ASTM D1238.

The thermoplastic resin may comprise a copolymer of an olefin monomer and a monomer having acidic side groups. In some examples, the olefin monomer may be selected from ethylene and propylene. In some examples, the monomer having acidic side groups may be selected from methacrylic acid and acrylic acid. In some examples, the thermoplastic resin may comprise a copolymer of an olefin monomer and a monomer selected from methacrylic acid and acrylic acid. In some examples, the thermoplastic resin may comprise a copolymer of ethylene and a monomer selected from methacrylic acid and acrylic acid.

In some examples, the polymer having acidic side groups is a copolymer of an olefin monomer and a monomer selected from acrylic acid and methacrylic acid. In some examples, the thermoplastic resin may comprise a copolymer of an olefin monomer and a monomer selected from acrylic acid and methacrylic acid.

The acidic side groups may be in the free acid form or may be in the anionic form and are associated with one or more counterions, typically metal counterions, for example a metal selected from alkali metals, such as lithium, sodium and potassium, alkaline earth metals, such as magnesium or calcium, and transition metals, such as zinc. The polymer having acidic side groups may be selected from resins such as copolymers of ethylene and ethylenically unsaturated acrylic or methacrylic acid; and ionomers thereof, such as methacrylic acid and ethylene-acrylic acid or methacrylic acid copolymers at least partially neutralized with metal ions (e.g., Zn, Na, Li), such as SURLYN ionomers. The polymer comprising acidic side groups can be a copolymer of ethylene and ethylenically unsaturated acrylic or methacrylic acid, wherein the ethylenically unsaturated acrylic or methacrylic acid comprises from 5% to about 25% by weight of the copolymer, and in some examples from 10% to about 20% by weight of the copolymer.

The thermoplastic resin may comprise two different polymers having acidic side groups. The two polymers having acidic side groups may have different acidity which may fall within the ranges mentioned above. The thermoplastic resin can comprise a first polymer having acidic side groups having an acidity of 50 to 110 mg KOH/g and a second polymer having acidic side groups having an acidity of 110 to 130 mg KOH/g.

The resin may comprise two different polymers having acidic side groups: a first polymer having acidic side groups having a melt flow rate of about 10 g/10 min to about 50 g/10 min and an acidity of 50 mg KOH/g to 110 mg KOH/g, and a second polymer having acidic side groups having a melt flow rate of about 50 g/10 min to about 120 g/10 min and an acidity of 110 mg KOH/g to 130 mg KOH/g. The first and second polymers may be free of ester groups.

The resin may comprise a copolymer of ethylene and acrylic acid and a copolymer of ethylene and methacrylic acid.

The resin may comprise two different polymers having acidic side groups: a first polymer in the form of a copolymer of ethylene (e.g., 92 to 85 wt%, in some examples about 89 wt%) and acrylic or methacrylic acid (e.g., 8 to 15 wt%, in some examples about 11 wt%) having a melt flow rate of 80 to 110 g/10 min, and a second polymer in the form of a copolymer of ethylene (e.g., about 80 to 92 wt%, in some examples about 85 wt%) and acrylic acid (e.g., about 18 to 12 wt%, in some examples about 15 wt%) having a melt viscosity lower than the melt viscosity of the first polymer, the second polymer having, for example, a melt viscosity of 15000 poise or less, in some examples 10000 poise or less, in some examples 1000 poise or less, a melt viscosity of 100 poise or less in some examples, 50 poise or less in some examples, and 10 poise or less in some examples. Melt viscosity can be measured using standard techniques. A rheometer, such as the commercially available AR-2000 rheometer from Thermal Analysis Instruments, can be used, using geometry: 25 mm steel plate-standard steel parallel plate and obtaining plate-to-plate rheological isotherm measurement of melt viscosity at 120 ℃ at a shear rate of 0.01 Hz.

In any of the resins mentioned above, the ratio of the first polymer having acidic side groups to the second polymer having acidic side groups can be from about 10:1 to about 2: 1. In another example, the ratio can be about 6:1 to about 3:1, and in some examples about 4: 1.

The resin may comprise a polymer having a melt viscosity of 15000 poise or less, in some examples 10000 poise or less, in some examples 1000 poise or less, in some examples 100 poise or less, in some examples 50 poise or less, in some examples 10 poise or less; the polymer may be a polymer having acidic side groups as described herein. The resin may comprise a first polymer having a melt viscosity of 15000 poise or more, in some examples 20000 poise or more, in some examples 50000 poise or more, in some examples 70000 poise or more; and in some examples, the resin may comprise a second polymer having a melt viscosity that is lower than the melt viscosity of the first polymer, in some examples a melt viscosity of 15000 poise or less, in some examples 10000 poise or less, in some examples 1000 poise or less, in some examples 100 poise or less, in some examples 50 poise or less, and in some examples 10 poise or less. The resin may comprise a first polymer having a melt viscosity of greater than 60000 poise, in some examples 60000 poise to 100000 poise, in some examples 65000 poise to 85000 poise; a second polymer having a melt viscosity of 15000 poise to 40000 poise, in some examples 20000 poise to 30000 poise, and a third polymer having a melt viscosity of 15000 poise or less, in some examples 10000 poise or less, in some examples 1000 poise or less, in some examples 100 poise or less, in some examples 50 poise or less, in some examples 10 poise or less; an example of a first polymer is Nucrel 960 (from DuPont), an example of a second polymer is Nucrel 699 (from DuPont), and an example of a third polymer is AC-5120 (from Honeywell). In some examples, the resin may comprise a first polymer having a melt viscosity of 15000 poise to 40000 poise, in some examples 20000 poise to 30000 poise, and a second polymer having a melt viscosity of 15000 poise or less, in some examples 10000 poise or less, in some examples 1000 poise or less, in some examples 100 poise or less, in some examples 50 poise or less, in some examples 10 poise or less; an example of a first polymer is Nucrel 699 (from DuPont) and an example of a second polymer is AC-5120 (from Honeywell). The first, second and third polymers may be polymers having acidic side groups as described herein. A rheometer, such as the commercially available AR-2000 rheometer from Thermal Analysis Instruments, can be used, using geometry: 25 mm steel plate-standard steel parallel plate and obtaining plate-to-plate rheological isotherm measurement of melt viscosity at 120 ℃ at a shear rate of 0.01 Hz.

If the resin comprises a single type of resin polymer, the resin polymer (excluding any other components of the electrostatic ink composition) may have a melt viscosity of 6000 poise or more, in some examples a melt viscosity of 8000 poise or more, in some examples a melt viscosity of 10000 poise or more, in some examples a melt viscosity of 12000 poise or more. If the resin comprises multiple polymers, all of the polymers of the resin may together form a mixture (excluding any other components of the electrostatic ink composition) having a melt viscosity of 6000 poise or more, in some examples 8000 poise or more, in some examples 10000 poise or more, and in some examples 12000 poise or more. Melt viscosity can be measured using standard techniques. A rheometer, such as the commercially available AR-2000 rheometer from Thermal Analysis Instruments, can be used, using geometry: 25 mm steel plate-standard steel parallel plate and obtaining plate-to-plate rheological isotherm measurement of melt viscosity at 120 ℃ at a shear rate of 0.01 Hz.

The resin may comprise two different polymers having acidic side groups selected from copolymers of ethylene and ethylenically unsaturated methacrylic or acrylic acid; and ionomers thereof, such as methacrylic acid and ethylene-acrylic acid or methacrylic acid copolymers at least partially neutralized with metal ions (e.g., Zn, Na, Li), such as SURLYN ionomers.

The resin may comprise (i) a first polymer that is a copolymer of ethylene and ethylenically unsaturated acrylic or methacrylic acid, wherein the ethylenically unsaturated acrylic or methacrylic acid comprises from 8% to about 16% by weight of the copolymer, in some examples from 10% to 16% by weight of the copolymer; and (ii) a second polymer that is a copolymer of ethylene and an ethylenically unsaturated acrylic or methacrylic acid, wherein the ethylenically unsaturated acrylic or methacrylic acid comprises from 12% to about 30% by weight of the copolymer, in some examples from 14% to about 20% by weight of the copolymer, in some examples from 16% to about 20% by weight of the copolymer, in some examples from 17% to 19% by weight of the copolymer.

In one example, the resin constitutes about 5 to 90 weight percent, in some examples about 5 to 80 weight percent, of the total solids content of the electrostatic ink composition. In another example, the resin constitutes about 10 to 60 weight percent of the total solids content of the electrostatic ink composition. In another example, the resin constitutes about 15 to 40 weight percent of the total solids content of the electrostatic ink composition. In another example, the resin constitutes about 60 to 95 weight percent, in some examples 65 to 90 weight percent, 65 to 80 weight percent of the total solids content of the electrostatic ink composition.

The resin may comprise a polymer having acidic side groups (which may be free of ester side groups) and a polymer having ester side groups, as described above. The polymer having ester side groups is in some examples a thermoplastic polymer. The polymer having ester side groups may further comprise acidic side groups. The polymer having ester side groups may be a copolymer of a monomer having ester side groups and a monomer having acidic side groups. The polymer may be a copolymer of a monomer having an ester side group, a monomer having an acidic side group, and a monomer without any acidic side group and ester side group. The monomer having an ester side group may be a monomer selected from esterified acrylic acid or esterified methacrylic acid. The monomer having acidic side groups may be a monomer selected from acrylic acid or methacrylic acid. The monomer without any acidic and ester side groups may be an olefin monomer including, but not limited to, ethylene or propylene. The esterified acrylic acid or esterified methacrylic acid may be an alkyl ester of acrylic acid or an alkyl ester of methacrylic acid, respectively. The alkyl group in the alkyl ester of acrylic or methacrylic acid may be an alkyl group having 1 to 30 carbons, in some examples 1 to 20 carbons, in some examples 1 to 10 carbons; in some examples selected from methyl, ethyl, isopropyl, n-propyl, tert-butyl, isobutyl, n-butyl and pentyl.

The polymer having ester side groups can be a copolymer of a first monomer having ester side groups, a second monomer having acidic side groups, and a third monomer that is an olefin monomer without any acidic and ester side groups. The polymer having ester side groups can be a copolymer of (i) a first monomer having ester side groups selected from esterified acrylic or methacrylic acids, in some examples alkyl esters of acrylic or methacrylic acid, (ii) a second monomer having acidic side groups selected from acrylic or methacrylic acid, and (iii) a third monomer that is an olefin monomer selected from ethylene and propylene. The first monomer may constitute 1 to 50 weight percent, in some examples 5 to 40 weight percent, in some examples 5 to 20 weight percent, in some examples 5 to 15 weight percent of the copolymer. The second monomer may constitute 1 to 50 weight percent of the copolymer, in some examples 5 to 40 weight percent of the copolymer, in some examples 5 to 20 weight percent of the copolymer, in some examples 5 to 15 weight percent of the copolymer. In some examples, the first monomer comprises 5 to 40 weight percent of the copolymer, the second monomer comprises 5 to 40 weight percent of the copolymer, and the third monomer comprises the remaining weight of the copolymer. In one example, the first monomer constitutes 5 to 15 weight percent of the copolymer, the second monomer constitutes 5 to 15 weight percent of the copolymer, and the third monomer constitutes the remaining weight of the copolymer. In one example, the first monomer constitutes from 8 to 12 weight percent of the copolymer, the second monomer constitutes from 8 to 12 weight percent of the copolymer, and the third monomer constitutes the remaining weight of the copolymer. In one example, the first monomer comprises about 10% by weight of the copolymer, the second monomer comprises about 10% by weight of the copolymer, and the third monomer comprises the remaining weight of the copolymer. The polymer having ester side groups may be selected from the group consisting of Bynel monomers comprising Bynel 2022 and Bynel 2002, commercially available from DuPont.

The polymer having ester side groups can comprise the total amount of resin polymer in the resin, for example 1 wt.% or more of the total amount of the one or more polymers having acidic side groups and the polymer having ester side groups. The polymer having ester side groups may constitute 5 wt.% or more of the total amount of resin polymers in the resin, in some examples 8 wt.% or more of the total amount of resin polymers in the resin, in some examples 10 wt.% or more of the total amount of resin polymers in the resin, in some examples 15 wt.% or more of the total amount of resin polymers in the resin, in some examples 20 wt.% or more of the total amount of resin polymers in the resin, in some examples 25 wt.% or more of the total amount of resin polymers in the resin, in some examples 30 wt.% or more of the total amount of resin polymers in the resin, in some examples 35 wt.% or more of the total amount of resin polymers in the resin. The polymer having ester side groups may constitute from 5 to 50 weight percent of the total amount of resin polymer in the resin, in some examples from 10 to 40 weight percent of the total amount of resin polymer in the resin, in some examples from 15 to 30 weight percent of the total amount of polymer in the resin.

The polymer having ester side groups may have an acidity of 50 mg KOH/g or more, in some examples 60 mg KOH/g or more, in some examples 70 mg KOH/g or more, in some examples 80 mg KOH/g or more. The polymer having ester side groups can have an acidity of 100 mg KOH/g or less, and in some examples 90 mg KOH/g or less. The polymer having ester side groups can have an acidity of 60 to 90 mg KOH/g, in some examples 70 to 80 mg KOH/g.

The polymer having ester side groups may have a melt flow rate of from about 10 g/10 min to about 120 g/10 min, in some examples from about 10 g/10 min to about 50 g/10 min, in some examples from about 20 g/10 min to about 40 g/10 min, in some examples from about 25 g/10 min to about 35 g/10 min.

In one example, the one or more polymers of the resin may be selected from the group consisting of toners of the Nucrel series (e.g., Nucrel 403 ™ Nucrel 407 ™, Nucrel 609HS ™, Nucrel 908HS, Nucrel 1202 HC. A Nucrel 30707;, Nucrel 1214;, Nucrel 903. A, Nucrel 3990;, Nucrel 910;, Nucrel 925;, Nucrel 699;, Nucrel 599;, Nucrel 960;, Nucrel 76;, Nucrel RX 2806;, Bynell 2002, Bynell 2014 and Bynell 2020 (E.I. du PONT)), toners of the Aclyn series (e.g., Aclyn 246, Aclyn 285 and Aclyn), AC-51295 and AC 580 (Honeycell) and AC 580 (e.g., the Lotader family and toners of Lotader (e.g., Lotader 3400, Lotader 8200, Lotader).

In some examples, the resin may constitute from 5 wt% to 99 wt% of the total solids content in the yellow LEP ink composition, in some examples, from 50 wt% to 90 wt% of the total solids content of the yellow LEP ink composition, in some examples, from 65 wt% to 80 wt% of the total solids content of the yellow LEP ink composition.

Liquid carrier

In some examples, the yellow LEP ink composition comprises a liquid carrier when printed. In general, the liquid carrier can serve as a dispersion medium for the other components in the yellow LEP ink composition. For example, the liquid carrier can comprise or be a hydrocarbon, silicone oil, vegetable oil, or the like. The liquid carrier can include, but is not limited to, an insulating non-polar, non-aqueous liquid that can serve as a medium for the toner particles. The liquid carrier may comprise a liquid having a viscosity of greater than about 10⁹A resistivity of about ohm ∙ cm. The liquid carrier can have a dielectric constant of less than about 5, and in some examples less than about 3. The liquid carrier may include, but is not limited to, hydrocarbons. The hydrocarbons may include, but are not limited to, aliphatic hydrocarbons, isomerized aliphatic hydrocarbons, branched chain aliphatic hydrocarbons, aromatic hydrocarbons, and combinations thereof. Examples of liquid carriers include, but are not limited to, aliphatic hydrocarbons, isoparaffinsCompounds, paraffin compounds, dearomatized compounds, and the like. In particular, liquid carriers may include, but are not limited to, Isopar-G, Isopar-H, Isopar-L, Isopar-M, Isopar-K, Isopar-V, Norpar 12, Norpar 13, Norpar 15, Exxol D40, Exxol D80, Exxol D100, Exxol D130 and Exxol D140 (each sold by EXXON CORATION); a Telen N-16, a Telen N-20, a Telen N-22, a Nisseki Naphthol L-tract, a Nisseki Naphthol M-tract, a Nisseki Naphthol H-tract, #0 Solvent L-tract, #0 Solvent M-tract, #0 Solvent H-tract, a Nisseki lsosol 300-tract, a Nisseki lsosol 400-tract, an AF-4-tract, an AF-5-tract, an AF-6-tract and an AF-7-tract (each sold by NIPPON OIL CORPORATION); an IP Solvent 1620 and an IP Solvent 2028 (each sold by IDEMITSU PETROCHEMICAL CO., LTD.); amsco OMS and Amsco 460 (each sold by AMERICAN MINERAL SPIRITS CORP.); and Electron, Positron, New II, Purogen HF (100% synthetic terpenes) (sold by ECOLINK ™).

The liquid carrier may constitute about 20% to 99.5% by weight of the yellow liquid electrostatic ink composition, in some examples 50% to 99.5% by weight of the yellow liquid electrostatic ink composition, prior to liquid electrophotographic printing. The liquid carrier may constitute about 40% to 90% by weight of the yellow liquid electrostatic ink composition prior to printing. The liquid carrier may constitute about 60% to 80% by weight of the yellow liquid electrostatic ink composition prior to printing. The liquid carrier may constitute about 90% to 99.5% by weight of the yellow liquid electrostatic ink composition, in some examples 95% to 99% by weight of the yellow liquid electrostatic ink composition, prior to printing.

The yellow liquid electrostatic ink composition may be substantially free of liquid carrier when electrostatically printed on a substrate. During and/or after the electrostatic printing process, the liquid carrier can be removed, for example by electrophoresis and/or evaporation during the printing process, to transfer substantially only the solid to the substrate. Substantially free of liquid carrier may refer to a yellow liquid xerographic ink having less than 5% by weight liquid carrier, in some examples less than 2% by weight liquid carrier, in some examples less than 1% by weight liquid carrier, and in some examples less than 0.5% by weight liquid carrier. In some examples, the yellow liquid xerographic ink is free of a liquid carrier.

Charge directors

In some examples, the yellow LEP ink composition further comprises a charge director. Charge directors may be added to impart and/or maintain sufficient electrostatic charge on the ink particles, which may be particles comprising thermoplastic resins. In some examples, the charge director may comprise ionic compounds, particularly metal salts of fatty acids, metal salts of sulfosuccinates, metal salts of oxyphosphoric acids, metal salts of alkyl-benzenesulfonic acids, metal salts of aromatic carboxylic or sulfonic acids, as well as zwitterionic and nonionic compounds such as polyoxyethylated alkylamines, lecithin, polyvinylpyrrolidone, organic acid esters of polyhydric alcohols, and the like. The charge director can be selected from, but is not limited to, oil-soluble petroleum sulfonates (e.g., neutral Calcium Petronate, neutral Barium Petronate, and basic Barium Petronate), polybutylene succinimides (e.g., OLOA1200 and Amoco 575) and glycerides (e.g., sodium salts of phosphorylated mono-and diglycerides having unsaturated and saturated acid substituents), sulfonates, including, but not limited to, Barium, sodium, Calcium, and aluminum salts of sulfonic acids. The sulfonic acids may include, but are not limited to, the sulfonic acids of alkyl sulfonic acids, aryl sulfonic acids, and alkyl succinates. The charge director can impart a negative or positive charge to the resin-containing particles of the yellow LEP ink composition.

In some examples, the yellow liquid electrostatic ink composition comprises a charge director comprising a simple salt. The ions that make up the simple salts are completely hydrophilic. The simple salt may comprise a metal selected from Mg, Ca, Ba, NH₄、Tert-butyl radicalAmmonium, Li⁺And Al³⁺Or a cation selected from any subgroup thereof. The simple salt may comprise a salt selected from SO₄ ^2-、PO₃ ^-、NO₃ ^-、HPO₄ ^2-、CO₃ ^2-Acetate, Trifluoroacetate (TFA), Cl^-、BF₄ ^-、F^-、ClO₄ ^-And TiO₃ ^4-Or an anion selected from any subgroup thereof. The simple salt may be selected from CaCO₃、Ba₂TiO₃、Al₂(SO₄)、Al(NO₃)₃、Ca₃(PO₄)₂、BaSO₄、BaHPO₄、Ba₂(PO₄)₃、CaSO₄、(NH₄)₂CO₃、(NH₄)₂SO₄、NH₄OAc, tert-butyl ammonium bromide, NH₄NO₃、LiTFA、Al₂(SO₄)₃、LiClO₄And LiBF₄Or any subgroup thereof.

In some examples, the liquid electrostatic ink composition comprises a composition comprising formula MA_nWherein M is a metal, n is the valence of M, and A is a compound of the formula (I) [ R ] R¹-O-C(O)CH₂CH(SO₃-)-C(O)-O-R²]Wherein R is¹And R²Each is an alkyl group. In some examples, R¹And R²Each is an aliphatic alkyl group. In some examples, R¹And R²Each independently is a C6-25 alkyl group. In some examples, the aliphatic alkyl group is linear. In some examples, the aliphatic alkyl group is branched. In some examples, the aliphatic alkyl group includes a straight chain of more than 6 carbon atoms. In some examples, R¹And R²The same is true. In some examples, R¹And R²At least one of is C₁₃H₂₇. In some examples, M is Na, K, Cs, Ca, or Ba.

In some examples, the charge director comprises nanoparticles of at least one micelle-forming salt and a simple salt as described above. Simple salts are salts that do not form micelles by themselves, although they may form the core of a micelle with a micelle-forming salt. General formula MA_nThe sulfosuccinate salt of (a) is an example of a micelle-forming salt. The charge director may be substantially free of an acid of the general formula HA, wherein a is as described above. The charge director may comprise micelles of said sulfosuccinate salt encapsulating at least some nanoparticles of a simple salt. The charge director may compriseAt least some of the nanoparticles are simple salt nanoparticles having a particle size of 200 nanometers or less, and/or in some examples 2 nanometers or greater.

The charge director may include one, some or all of (i) soy lecithin, (ii) a barium sulfonate salt, such as basic barium petroleum sulfonate (BBP), and (iii) an isopropylamine sulfonate salt. Basic barium petroleum sulfonate is a barium sulfonate salt of a hydrocarbon alkyl group of 21 to 26 carbon atoms and is available, for example, from Chemtura. An exemplary isopropylamine sulfonate is isopropylamine dodecylbenzene sulfonate available from Croda.

In some examples, the charge director constitutes about 0.001 wt% to 20 wt%, in some examples 0.01 wt% to 10 wt%, in some examples 0.01 wt% to 5 wt% of the total solids content of the liquid electrostatic ink composition. In some examples, the charge director constitutes about 1 to 4 wt% of the total solids content of the liquid electrostatic ink composition, in some examples 2 to 4 wt% of the total solids content of the electrostatic ink composition.

In some examples, the charge director is present in an amount sufficient to achieve a charge director of 500 pmho/cm or less, in some examples 450 pmho/cm or less, in some examples 400 pmho/cm or less, in some examples 350 pmho/cm or less, in some examples 300 pmho/cm or less, in some examples 250 pmho/cm or less, in some examples 200 pmho/cm or less, in some examples 190 pmho/cm or less, in some examples 180 pmho/cm or less, in some examples 170 pmho/cm or less, in some examples 160 pmho/cm or less, in some examples 150 pmho/cm or less, in some examples 140 pmho/cm or less, in some examples 130 pmho/cm or less, in some examples, a particle conductivity amount of 120 pmho/cm or less, in some examples 110 pmho/cm or less, and in some examples about 100 pmho/cm is present. In some examples, the charge director is present in an amount sufficient to achieve 50 pmho/cm or greater, in some examples, 60 pmho/cm or greater, in some examples, 70 pmho/cm or greater, in some examples, 80 pmho/cm or greater, in some examples, 90 pmho/cm or greater, in some examples, about 100 pmho/cm, in some examples, 150 pmho/cm or more, in some examples, 200 pmho/cm or greater, in some examples, 250 pmho/cm or greater, in some examples, 300 pmho/cm or greater, in some examples, 350 pmho/cm or greater, in some examples 400 pmho/cm or greater, in some examples 450 pmho/cm or greater, in some examples, a particle conductivity of 500 pmho/cm or greater is present in an amount. In some examples, the charge director is present in an amount sufficient to achieve a charge director of 50 to 500 pmho/cm, in some examples 60 to 450 pmho/cm, in some examples 70 to 400 pmho/cm, in some examples 80 to 350 pmho/cm, in some examples 90 to 300 pmho/cm, in some examples 100 to 250 pmho/cm, in some examples 110 to 200 pmho/cm, in some examples 120 to 500 pmho/cm, in some examples 130 to 450 pmho/cm, in some examples 140 to 400 pmho/cm, in some examples 150 to 350 pmho/cm, in some examples, a particle conductivity amount of 160 to 300 pmho/cm is present.

In some examples, the charge director is present in an amount from 3 mg/g to 50 mg/g, in some examples from 3 mg/g to 45 mg/g, in some examples from 10 mg/g to 40 mg/g, in some examples from 5 mg/g to 35 mg/g, in some examples from 20 mg/g to 35 mg/g, in some examples from 22 mg/g to 34 mg/g (where mg/g refers to mg/g per gram of solids of the liquid electrostatic ink composition).

Charge adjuvant

In some examples, the yellow LEP ink composition further comprises a charge adjuvant. The charge adjuvant may facilitate charging of the particles in the presence of the charge director. The methods described herein may involve the addition of a charge adjuvant at any stage. The charge adjuvant may include, for example, barium petroleum sulfonate, calcium petroleum sulfonate, Co salt of naphthenic acid, Ca salt of naphthenic acid, Cu salt of naphthenic acid, Mn salt of naphthenic acid, Ni salt of naphthenic acid, Zn salt of naphthenic acid, Fe salt of naphthenic acid, Ba salt of stearic acid, Co salt of stearic acid, Pb salt of stearic acid, Zn salt of stearic acid, Al salt of stearic acid, Zn salt of stearic acid, Cu salt of stearic acid, Pb salt of stearic acid, Fe salt of stearic acid, metal carboxylate (e.g., aluminum tristearate, aluminum octoate, lithium heptoate, iron stearate, iron distearate, barium stearate, chromium stearate, magnesium octoate, calcium stearate, iron naphthenate, zinc naphthenate, manganese heptoate, zinc heptanoate, barium octoate, aluminum octoate, cobalt octoate, manganese octoate, and zinc octoate), cobalt linoleate, manganese linoleate, lead linoleate, zinc linoleate, calcium oleate, zinc palmitate, calcium linoleate, zinc linoleate, calcium linoleate, zinc palmitate, calcium stearate, magnesium linoleate, magnesium stearate, magnesium linoleate, magnesium stearate, magnesium linoleate, magnesium stearate, magnesium linoleate, magnesium stearate, magnesium linoleate, magnesium stearate, magnesium linoleate, magnesium stearate, magnesium, Calcium resinate, cobalt resinate, manganese resinate, lead resinate, zinc resinate, AB diblock copolymers of 2-ethylhexyl methacrylate-co-calcium methacrylate and ammonium salts, copolymers of alkyl acrylamidoglycolate alkyl ethers (e.g., methyl acrylamidoglycolate methyl ether-co-vinyl acetate), or hydroxy bis (3, 5-di-tert-butylsalicylic acid) aluminate monohydrate (3,5-di-tert-butyl salicylic acid) aluminum salt monohydrate. In one example, the charge adjuvant is or comprises aluminum di-or tristearate. In some examples, the charge adjuvant is VCA (aluminum stearate and aluminum palmitate, available from Sigma Aldrich).

The charge adjuvant may be present in an amount of about 0.1 to 5% by weight, in some examples about 0.1 to 1% by weight, in some examples about 0.3 to 0.8% by weight, in some examples about 1 to 5% by weight, in some examples about 1 to 3% by weight, in some examples about 1.5 to 2.5% by weight of the total solids content of the liquid electrostatic ink composition.

The charge adjuvant may be present in an amount of less than 5% by weight, in some examples in an amount of less than 4.5% by weight, in some examples in an amount of less than 4% by weight, in some examples in an amount of less than 3.5% by weight, in some examples in an amount of less than 3% by weight, in some examples in an amount of less than 2.5% by weight, in some examples in an amount of less than 2% by weight of the total solids content of the liquid electrostatic ink composition.

In some examples, the liquid electrostatic ink composition further comprises a salt of a multivalent cation and a fatty acid anion, for example, as a charge adjuvant. Salts of multivalent cations and fatty acid anions may serve as charge adjuvants. The multivalent cation may be a divalent or trivalent cation in some examples. In some examples, the multivalent cation is selected from group 2, transition metals, and groups 3 and 4 of the periodic table. In some examples, the multivalent cation comprises a metal selected from the group consisting of Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al, and Pb. In some examples, the multivalent cation is Al³⁺. The fatty acid anion may be selected from saturated or unsaturated fatty acid anions. The fatty acid anion may be selected from C₈To C₂₆Fatty acid anion, in some examples C₁₄To C₂₂Fatty acid anion, in some examples C₁₆To C₂₀Fatty acid anion, in some examples C₁₇、C₁₈Or C₁₉A fatty acid anion. In some examples, the fatty acid anion is selected from the group consisting of octanoate anion, decanoate anion, laurate anion, myristate anion, palmitate anion, stearate anion, arachidic anion, behenic anion, and cerotic anion.

The charge adjuvant, which may be, for example, or comprise a salt of a multivalent cation and a fatty acid anion, may be present in an amount of 0.1 wt% to 5 wt% of the total solids content of the liquid electrostatic ink composition, in some examples in an amount of 0.1 wt% to 3 wt% of the total solids content of the liquid electrostatic ink composition, in some examples in an amount of about 1 wt% to 3 wt% of the total solids content of the liquid electrostatic ink composition, in some examples in an amount of about 1.5 wt% to 2.5 wt% of the total solids content of the liquid electrostatic ink composition.

Dispersing agent

In some examples, the yellow LEP ink composition may further comprise a dispersant. In some examples, the dispersant may be a polymeric dispersant. In some examples, the polymeric dispersant may be a basic polymeric dispersant. In some examples, the polymeric dispersant may be a polymeric amine dispersant. In some examples, the polymeric amine dispersant may be a polyisobutylene succinimide based dispersant.

In some examples, a dispersant, such as an amine-containing dispersant, can be present in an amount of 3 wt% or more of the weight of the pigment, such as 4 wt% or more, 5 wt% or more, 6 wt% or more, 7 wt% or more, 8 wt% or more, 9 wt% or more, or 10 wt% or more of the weight of the pigment. In some examples, a dispersant, such as an amine-containing dispersant, can be present in an amount of 10% by weight or less of the weight of the pigment, such as 9% by weight or less, 8% by weight or less, 7% by weight or less, 6% by weight or less, 5% by weight or less, 4% by weight or less, or 3% by weight or less of the weight of the pigment. In some examples, a dispersant, such as an amine-containing dispersant, can be present in an amount of 3 to 10 weight percent of the pigment weight, such as 4 to 9 weight percent, 5 to 8 weight percent, or 6 to 7 weight percent of the pigment weight.

In some examples, a dispersant, such as an amine-containing dispersant, can be present in the yellow LEP ink composition in an amount of up to about 5% by weight of the non-volatile solids of the yellow LEP ink composition, such as about 4.5% by weight or less, about 4% by weight or less, about 3.5% by weight or less, about 3% by weight or less, about 2.5% by weight or less, about 2% by weight or less, about 1.5% by weight or less, or about 1% by weight or less of the non-volatile solids of the yellow LEP ink composition. In some examples, a dispersant, such as an amine-containing basic dispersant, can be present in the yellow LEP ink composition in an amount of about 0.1% by weight or more of the non-volatile solids of the yellow LEP ink composition, such as about 0.2% by weight or more, about 0.3% by weight or more, or about 0.4% by weight or more, about 0.5% by weight or more, about 0.2% by weight or more, about 0.3% by weight or more, or about 0.4% by weight or more, or about 0.5% by weight or more, about 1% by weight or more, or about 1.5% by weight or more. In some examples, a dispersant, such as an amine-containing basic dispersant, can be present in the yellow LEP ink composition in an amount from 0% to about 5% by weight of the non-volatile solids of the yellow LEP ink composition, such as from about 0.1% to about 5%, from about 0.2% to about 4.5%, from about 0.3% to about 4%, from about 0.4% to about 3.5%, from about 0.5% to about 3%, from about 1% to about 2.5%, or from about 1.5% to about 2% by weight of the non-volatile solids of the yellow LEP ink composition.

In some examples, the basic polymeric dispersant comprises a basic anchor group, which may be an amine group. In some examples, each basic polymeric dispersant molecule comprises a polyamine anchor group or a monoamine anchor group, and in some examples each basic polymeric dispersant molecule comprises a polyamine anchor group. In some examples, the basic polymeric dispersant comprises a polyester. In some examples, the basic polymeric dispersant comprises a polyester and an amine anchor group. In some examples, the basic polymeric dispersant comprises an amine group-containing terminated polyester bonded to the polyester through an amide linkage. In some examples, the polymeric amine dispersant comprises a copolymer having pendant stearic acid groups.

In some examples, the basic polymeric dispersant comprises a copolymer. In some examples, the basic polymeric dispersant comprises a block copolymer having a plurality of anchor groups, such as an ABA block copolymer or a BAB block copolymer or a random copolymer. In some examples, the polymeric dispersant comprises a comb copolymer.

In some examples, the polymeric dispersant comprises a polyisobutylene succinimide-containing dispersant. In some examples, the polymeric dispersant has the formula

Wherein n and m may be integers from 1 to 1000.

In some examples, the polymeric dispersant may be Solsperse J560 (which is also known as Lubrizol 6406) or OLOA 1200.

In some examples, the polymeric amine dispersant was Solplus P6000 (available from Lubrizol) having a TBN of about 400 mgKOH/g of material.

In some examples, the amine-containing basic dispersant has a Total Base Number (TBN) of at least about 10 mgKOH/g of material, in some examples, at least about 20 mgKOH/g of material, in some examples, at least about 30 mgKOH/g of material, in some examples, at least about 40 mgKOH/g of material, in some examples, at least about 50 mgKOH/g of material, in some examples, 60 mgKOH/g of material, and in some examples, at least about 70 mgKOH/g of material. In some examples, the amine-containing basic dispersant has a TBN of about 100 mg KOH/g of material or less, in some examples about 90 mg KOH/g of material or less, in some examples about 80 mg KOH/g of material or less, in some examples about 70 mg KOH/g of material or less, and in some examples about 60 mg KOH/g of material or less. In some examples, the basic dispersant has a Total Base Number (TBN) of from about 10 to about 100, in some examples from about 20 to about 90, in some examples from about 30 to about 80, in some examples from about 40 to about 70, in some examples from about 10 to about 60, and in some examples from about 20 to about 50 mgKOH/g of material.

In some examples, the amine-containing basic dispersant has a Total Base Number (TBN) of about 300 to about 500, in some examples about 380 to about 420, and in some examples about 400 mgKOH/g of material.

In some examples, the amine-containing basic dispersant has a Total Base Number (TBN) of less than about 500 mgKOH/g of material, in some examples less than about 450 mgKOH/g of material, in some examples less than about 425 mgKOH/g of material, in some examples less than about 420 mgKOH/g of material, and in some examples less than about 410 mgKOH/g of material.

In some examples, the dispersant has a weight average Molecular Weight (MW) of about 2 kg/mol or more, such as about 2.1 kg/mol or more, about 2.2 kg/mol or more, about 2.3 kg/mol or more, about 2.4 kg/mol or more, about 2.5 kg/mol or more, about 2.6 kg/mol or more, about 2.7 kg/mol or more, about 2.8 kg/mol or more, about 2.9 kg/mol or more, or about 3 kg/mol. In some examples, the dispersant has a weight average Molecular Weight (MW) of about 5 kg/mol or less, such as about 4.9 kg/mol or less, about 4.8 kg/mol or less, about 4.7 kg/mol or less, about 4.6 kg/mol or less, about 4.5 kg/mol or less, about 4.4 kg/mol or less, about 4.3 kg/mol or less, about 4.2 kg/mol or less, about 4.1 kg/mol or less, or about 4 kg/mol. In some examples, the dispersant has a weight average Molecular Weight (MW) of about 2 kg/mol to about 5 kg/mol, such as about 2.1 kg/mol to about 4.9 kg/mol, about 2.2 kg/mol to about 4.8 kg/mol, about 2.3 kg/mol to about 4.7 kg/mol, about 2.4 kg/mol to about 4.6 kg/mol, about 2.5 kg/mol to about 4.5 kg/mol, about 2.6 kg/mol to about 4.4 kg/mol, about 2.7 kg/mol to about 4.3 kg/mol, about 2.8 kg/mol to about 4.2 kg/mol, about 2.9 kg/mol to about 4.1 kg/mol, or about 3 kg/mol to about 4 kg/mol. In some examples, the dispersant may have a weight average molecular weight of about 3.5 kg/mol.

In some examples, the polymeric amine dispersant may be a solution or dispersion of the active dispersant in a carrier fluid prior to addition to the ink composition. In some examples, the polymeric amine dispersant may be added as a 50 wt% or higher active solution, for example, a 60 wt% or higher active solution or a 62 wt% active solution in a carrier fluid, such as mineral oil or dipropylene glycol. The amount of dispersant referred to herein is the amount of active ingredient of the solution or dispersion.

Other additives

The yellow LEP ink composition may comprise another additive or a plurality of other additives. One or more other additives may be added at any stage of the process. The one or more other additives may be selected from charge adjuvants, waxes, surfactants, viscosity modifiers and compatibility additives. The wax may be an incompatible wax. As used herein, "incompatible wax" may refer to a wax that is incompatible with the resin. Specifically, during and after transfer of an ink film (e.g., from an intermediate transfer member, which may be a heated blanket) onto a print substrate, the wax phase separates from the resin phase as the resin frit mixture on the print substrate cools. In some examples, the LEP ink composition includes silica, which can be added, for example, to improve the durability of images made using LEP inks. The other additives may constitute 10 wt% or less of the total solids content of the electrostatic ink composition, in some examples 5 wt% or less of the total solids content of the electrostatic ink composition, in some examples 3 wt% or less of the total solids content of the electrostatic ink composition.

Printed substrate

In one aspect, a printed substrate is provided, comprising a substrate; and a yellow liquid electrophotographic printed ink composition disposed thereon (i.e., disposed on the substrate); wherein the yellow liquid electrophotographic printing ink composition comprises: a thermoplastic resin comprising a polymer having acidic side groups; and a colorant comprising a yellow pigment, wherein the yellow pigment comprises a hydrazone compound. In some examples, the colorant is as described herein.

In some examples, the printed substrate can include a substrate and a plurality of different ink compositions (e.g., liquid electrophotographic printing ink compositions) on the substrate, at least one of which is a yellow liquid electrophotographic printing ink composition as described above. In some examples, the printed substrate can include a substrate and a plurality of different ink compositions (e.g., liquid electrophotographic printed ink compositions) on the substrate, at least one of which is a yellow liquid electrophotographic printed ink composition comprising: a thermoplastic resin comprising a polymer having acidic side groups; and a colorant comprising a yellow pigment, wherein the yellow pigment comprises a hydrazone compound.

In some examples, the printed substrate further comprises a liquid electrophotographic printing ink composition selected from the group consisting of a magenta liquid electrophotographic printing ink composition, a cyan liquid electrophotographic printing ink composition, a black liquid electrophotographic printing ink composition; and mixtures of any two thereof. In some examples, the printed substrate further comprises a magenta liquid electrophotographic printing ink composition and a cyan liquid electrophotographic printing ink composition. In some examples, the printed substrate further comprises a magenta liquid electrophotographic printing ink composition, a cyan liquid electrophotographic printing ink composition, and a black liquid electrophotographic printing ink composition. In some examples, the printed substrate comprises a substrate; a yellow liquid electrophotographic printing ink composition disposed on the substrate and an additional liquid electrophotographic printing ink composition disposed on the substrate, wherein the additional liquid electrophotographic printing ink composition is selected from the group consisting of a magenta liquid electrophotographic printing ink composition, a cyan liquid electrophotographic printing ink composition, a black liquid electrophotographic printing ink composition, and combinations thereof.

In some examples, the printed substrate comprises a substrate and a yellow liquid electrophotographic printed ink composition disposed on the substrate, wherein the yellow electrophotographic printed ink composition is as described above. In some examples, the printed substrate comprises a substrate and a yellow liquid electrophotographic printed ink composition disposed on the substrate, wherein the yellow liquid electrophotographic printed ink composition is as described above and wherein the yellow liquid electrophotographic printed ink composition is substantially free of a carrier liquid. In some examples, the printed substrate comprises a substrate and a yellow liquid electrophotographic printed ink composition disposed on the substrate, wherein the yellow liquid electrophotographic printed ink composition is as described above and wherein the yellow liquid electrophotographic printed ink composition is free of a carrier liquid.

In some examples, the yellow liquid electrophotographic printed ink composition forms a layer having a thickness of 1 μm or less, e.g., 0.8 μm or less, 0.7 μm or less, 0.65 μm or less, 0.6 μm or less, 0.55 μm or less, 0.5 μm or less, 0.45 μm or less, when printed at 100% coverage. In some examples, the yellow electrophotographic printed ink composition, when printed at 100% coverage, forms a layer having a thickness of 0.4 μm to 1 μm, e.g., 0.45 μm to 0.8 μm, 0.5 μm to 0.7 μm, 0.4 μm to 0.65 μm, 0.45 μm to 0.6 μm, 0.45 μm to 0.55 μm, 0.4 μm to 0.5 μm.

Substrate

In some examples, the substrate may be any suitable substrate. In some examples, the substrate may be any suitable substrate on which an image can be printed. The substrate may comprise a material selected from organic or inorganic materials. The material may comprise a natural polymeric material, such as cellulose. The material may comprise a synthetic polymeric material, such as a polymer formed from olefin monomers, including but not limited to polyethylene, polypropylene, and copolymers, such as styrene-polybutadiene. The polypropylene may be a biaxially oriented polypropylene in some examples. The material may comprise a metal which may be sheet-like. The metal may be selected from or made of, for example, aluminum (Al), silver (Ag), tin (Sn), copper (Cu), and mixtures thereof. In one example, the substrate comprises cellulose paper. In one example, the cellulose paper is coated with a polymeric material, such as a polymer formed from a styrene-butadiene resin. In some examples, the cellulosic material has an inorganic material bonded to its surface (prior to printing with the ink) with a polymeric material, wherein the inorganic material may be selected from, for example, kaolinite or calcium carbonate. In some examples, the substrate is a cellulosic substrate, such as paper. In some examples, the cellulosic substrate may be a coated cellulosic substrate. In some examples, a primer may be coated onto the substrate prior to printing the electrophotographic ink composition onto the substrate.

In some examples, the substrate may be a plastic film. In some examples, the substrate may be any plastic film on which an image can be printed. The plastic film may comprise synthetic polymeric materials such as polymers formed from olefin monomers including, for example, polyethylene and polypropylene, and copolymers such as styrene-polybutadiene polymers. The polypropylene may be a biaxially oriented polypropylene in some examples. In some examples, the plastic film may comprise polyethylene terephthalate.

In some examples, the plastic film is a film. In some examples, the plastic film comprises Polyethylene (PE), Linear Low Density Polyethylene (LLDPE), Low Density Polyethylene (LDPE), Medium Density Polyethylene (MDPE), High Density Polyethylene (HDPE), polypropylene (PP), cast polypropylene (cPP) or biaxially oriented polypropylene (BOPP), Oriented Polyamide (OPA) or polyethylene terephthalate (PET).

In some examples, the substrate comprises multiple layers of material laminated together to form a pre-laminated substrate. In some examples, the substrate comprises multiple layers of material laminated together to form a pre-laminated substrate, wherein the plastic film forms a surface on which the electrophotographic ink can be applied. In some examples, the substrate comprises multiple film layers laminated together to form a pre-laminated substrate, wherein the plastic film forms a surface on which the electrophotographic ink can be applied. In one example, the substrate may be a plastic film laminated to, adhered to, or coated on cellulose paper. In some examples, the substrate comprises a plurality of layers of material selected from polymeric materials (e.g., polymeric materials selected from PE, LLDPE, MDPE, PP, BOPP, PET, and OPA), metallic materials (e.g., metallic foils such as aluminum foil, or metallized films such as met-PET, met-BOPP, or any other metallized substrate), paper, and combinations thereof. In some examples, the substrate comprises a plurality of film layers of plastics material, such as a combination of films selected from PE, LLDPE, MDPE, PP, BOPP, PET and OPA, laminated together to form a pre-laminated substrate. In some examples, the pre-laminated substrate comprises a paper/Alu/PE, PET/Al/PE, BOPP/met-BOPP, or PET/PE laminate.

In some examples, the substrate comprises a thin material, wherein the material has a thickness of 600 μm or less, such as 250 μm or less, such as 200 μm or less, such as 150 μm or less, such as 100 μm or less, such as 90 μm or less, such as 80 μm or less, such as 70 μm or less, such as 60 μm or less, such as 50 μm or less, such as 40 μm or less, such as 30 μm or less, such as 20 μm or less, such as 15 μm or less. In some examples, the material is about 12 μm thick.

In some examples, the substrate comprises a thin material, wherein the material has a thickness of 12 μm or more, such as 15 μm or more, such as 20 μm or more, such as 30 μm or more, such as 40 μm or more, such as 50 μm or more, such as 60 μm or more, such as 70 μm or more, such as 80 μm or more, such as 90 μm or more. In some examples, the material has a thickness of about 100 μm or greater, and in some examples about 100 μm or greater.

In some examples, the substrate comprises a thin material, wherein the material is 12 μm to 600 μm thick, in some examples 15 μm to 250 μm thick, in some examples 20 μm to 200 μm thick, in some examples 30 μm to 150 μm thick, in some examples 40 μm to 100 μm thick, in some examples 50 μm to 150 μm thick, in some examples 60 μm to 100 μm thick, in some examples 70 to 90 μm thick.

Method for producing printed substrates

In one aspect, a method of producing a printed substrate is provided that includes applying a yellow liquid electrophotographic ink composition to a substrate with a liquid electrophotographic printer. In some examples, a method of producing a printed substrate is provided that includes applying a yellow liquid electrophotographic ink composition to a substrate with a liquid electrophotographic printer; wherein the yellow liquid electrophotographic ink composition comprises: a thermoplastic resin comprising a polymer having acidic side groups; and a colorant comprising a yellow pigment, wherein the yellow pigment comprises a hydrazone compound.

In some examples, a method of producing a printed substrate comprises applying a yellow liquid electrophotographic ink composition to a substrate with an electrophotographic printer; wherein the yellow liquid electrophotographic ink composition is as described above.

In some examples, a method of producing a printed substrate comprises applying a plurality of different LEP ink compositions to a substrate with a liquid electrophotographic printer, wherein at least one comprises a yellow liquid electrophotographic ink composition as described above. In some examples, the method of producing a printed substrate comprises applying a plurality of different LEP ink compositions to a substrate with a liquid electrophotographic printer, wherein at least one consists of a yellow liquid electrophotographic ink composition as described above.

In some examples, a method of producing a printed substrate includes applying a yellow LEP ink composition to a substrate with an electrophotographic printer, and further includes applying a black ink composition, a cyan ink composition, and a magenta ink composition. In some examples, the method of producing a printed substrate comprises applying a yellow LEP ink composition to a substrate with an electrophotographic printer, and further comprises applying a black LEP ink composition, a cyan LEP ink composition, and a magenta LEP ink composition to a substrate with an electrophotographic printer.

In some examples, applying the LEP ink composition to the substrate with an electrophotographic printer includes contacting the LEP ink composition with an electrostatic latent image on a surface to produce a developed image, and transferring the developed image to the substrate, in some examples via an intermediate transfer member.

In some examples, the surface on which the (latent) electrostatic image is formed or developed may be a rotating member, for example, in the form of a cylinder. The surface on which the (latent) electrostatic image is formed or developed may form part of a Photo Imaging Plate (PIP). The method may involve passing the ink composition between a fixed electrode and a rotating member, which may be or be in contact with a member having a surface with a (latent) electrostatic image thereon. A voltage is applied between the stationary electrode and the rotating member to attach the particles to the surface of the rotating member. The intermediate transfer member, if present, may be a flexible rotating member that may be heated to a temperature of, for example, 80 to 160 ℃.

Process for producing yellow liquid electrophotographic ink composition

In some examples, a method of producing a yellow liquid electrophotographic ink composition can include combining a thermoplastic resin and a colorant. In some examples, a method of producing a yellow LEP ink composition can include combining a thermoplastic resin, a colorant, and a liquid carrier.

In some examples, a method of producing a yellow liquid electrophotographic ink composition may include combining a dispersant, a colorant, and a thermoplastic resin. In some examples, a method of producing a yellow LEP ink composition can include combining a dispersant, a colorant, a thermoplastic resin, and a liquid carrier. In some examples, a method of producing a yellow LEP ink composition can include combining a colorant and a dispersant with a liquid carrier, and then adding a thermoplastic resin to the combined colorant and dispersant.

In some examples, combining the colorant and the dispersant includes grinding the colorant and the dispersant.

In some examples, the dispersing agent is liquid or in solution and is combined with the colorant to form a slurry prior to addition to the thermoplastic resin. In some examples, the dispersant is in liquid or solution form and is milled with the colorant to form a slurry prior to addition to the resin, which may be further milled after addition to the resin. In some examples, the dispersant is a solid and is milled with the colorant and resin (e.g., without first combining the dispersant and colorant).

In some examples, the thermoplastic resin is combined with the liquid carrier prior to adding the colorant. In some examples, a thermoplastic resin is combined with a liquid carrier to form a first composition; combining a colorant with a liquid carrier to form a second composition; and combining the first composition with the second composition to form a yellow LEP ink composition. In some examples, a thermoplastic resin is combined with a liquid carrier to form a first composition; combining a colorant and a dispersant with a liquid carrier to form a second composition; and combining the first composition with the second composition to form a yellow LEP ink composition. In some examples, the liquid carrier in the first composition is the same or different from the liquid carrier in the second composition. In some examples, the liquid carrier in the first composition is the same as the liquid carrier in the second composition.

In some examples, the method of producing the yellow LEP ink composition includes adding a charge adjuvant to the yellow LEP ink composition. In some examples, the charge adjuvant may be added to the yellow LEP ink composition before, during, or after combining the colorant and the thermoplastic resin. In some examples, the charge adjuvant may be added to the yellow LEP ink composition before, during, or after combining the colorant, thermoplastic resin, and dispersant.

In some examples, the method of producing the yellow LEP ink composition comprises adding a charge director to the yellow LEP ink composition. In some examples, the charge director is added to the yellow LEP ink composition before, during, or after the charge adjuvant is added to the yellow LEP ink composition. In some examples, the charge director can be added to the yellow LEP ink composition before, during, or after combining the colorant and the thermoplastic resin. In some examples, the charge director can be added to the yellow LEP ink composition before, during, or after combining the colorant, thermoplastic resin, and dispersant.

In some examples, the method of producing a yellow LEP ink composition can include suspending the thermoplastic resin in a carrier liquid prior to adding the thermoplastic resin to the colorant. In some examples, the method may include suspending the first thermoplastic resin and the second thermoplastic resin in a carrier liquid. In some examples, the yellow LEP ink composition comprises chargeable particles comprising a first thermoplastic resin and a second thermoplastic resin. In some examples, a method of producing a yellow LEP ink composition can include suspending chargeable particles comprising a first thermoplastic resin and a second thermoplastic resin in a carrier liquid.

In some examples, a method of producing a yellow LEP ink composition can include dispersing a first thermoplastic resin and a second thermoplastic resin in a carrier liquid. In some examples, a method of producing a yellow LEP ink composition can include dispersing chargeable particles comprising a first thermoplastic resin and a second thermoplastic resin in a carrier liquid.

In some examples, a method of producing a yellow LEP ink composition may include combining a thermoplastic resin (e.g., a first thermoplastic resin) with a carrier liquid and subsequently adding an additional resin (e.g., a second resin). In some examples, a method of producing a yellow LEP ink composition includes combining a resin (e.g., a first resin) with a carrier liquid to form a paste and then adding another resin (e.g., a second resin). In some examples, the resin and carrier liquid are combined and heated to an elevated temperature, followed by the addition of other resins, which may also have been heated to an elevated temperature. In some examples, the resin and carrier liquid are combined and heated to a temperature above the melting point of the resin, followed by the addition of the other resin, which may also have been heated to a temperature above its melting point. In some examples, the resin and carrier liquid are combined and heated until the resin melts and/or dissolves in the carrier liquid, and then additional resin is added. In some examples, adding the other resin to the combined resin and carrier liquid includes mixing the other resin with the combined resin and carrier liquid.

The melting point of the resin can be determined, for example, by differential scanning calorimetry using ASTM D3418.

In some examples, the resin and carrier liquid are combined and heated to a temperature of at least 70 ℃, such as at least 80 ℃, such as at least 90 ℃, such as at least 100 ℃, such as at least 110 ℃, such as at least 120 ℃, such as 130 ℃, for example to melt the resin. In some examples, the other resin is heated prior to addition to the combined resin and carrier liquid. In some examples, the other resin is heated to at least 30 ℃, in some examples at least 40 ℃, in some examples at least 45 ℃, in some examples at least 50 ℃ prior to addition to the combined resin and carrier liquid. In some examples, the other resin is heated to 100 ℃ or less, in some examples 90 ℃ or less, in some examples 80 ℃ or less, in some examples 75 ℃ or less, in some examples 70 ℃ or less, in some examples 60 ℃ or less prior to addition to the combined resin and carrier liquid. In some examples, the other resin is heated prior to addition to the first resin and the carrier liquid to reduce the viscosity of the other resin.

In some examples, the method includes combining a first resin with a carrier liquid to form a first composition; combining a second resin with a carrier liquid to form a second composition; and subsequently combining the first composition and the second composition to form a liquid electrophotographic ink composition. In some examples, the method includes combining a first resin with a carrier liquid to form a first paste; combining a second resin with a carrier liquid to form a second paste; and subsequently combining the first paste and the second paste to form the liquid electrophotographic ink composition. In some examples, the first resin and the carrier liquid are combined and heated to an elevated temperature to form a first heated composition; combining and heating the second resin and the carrier liquid to an elevated temperature to form a second heated composition; and subsequently combining the first heating composition and the second heating composition. In some examples, the first resin and the carrier liquid are combined and heated to a temperature above the melting point of the first resin to form a first heated composition; combining and heating the second resin and the carrier liquid to a temperature above the melting point of the second resin to form a second heated composition; and subsequently combining the first heating composition and the second heating composition. In some examples, the first composition and the second composition are heated to the same temperature, which may be a temperature above the melting temperature of all resins.

In some examples, a method of producing a yellow LEP ink composition includes mixing a first resin and a second resin together, and then combining the resin mixture with a carrier liquid.

In some examples, the first resin and the second resin are combined with a carrier liquid and subsequently heated to an elevated temperature. In some examples, the first resin and the second resin are combined with a carrier liquid and subsequently heated to a temperature above the melting point of at least one resin, optionally all resins. In some examples, the first resin and the second resin are combined with the carrier liquid and then heated to a temperature of at least 70 ℃, such as at least 80 ℃, such as at least 90 ℃, such as at least 100 ℃, such as at least 110 ℃, such as at least 120 ℃, such as 130 ℃, for example to melt at least one resin, optionally all of the resins. In some examples, the combined first resin, second resin, and carrier liquid are heated until all of the resins melt and/or dissolve in the carrier liquid.

In some examples, a method of producing a yellow liquid electrophotographic ink composition includes combining a first resin, a second resin, and a carrier liquid.

In some examples, the chargeable particles comprise a first resin and a second resin.

Melting and/or dissolving the resin(s) in the carrier liquid can result in the carrier fluid appearing clear and uniform. In some examples, the resin (or resins) and carrier liquid are heated before, during, or after mixing.

In some examples, the resin (or resins) and carrier liquid are mixed at a mixing rate of 500 rpm or less, such as 400 rpm or less, such as 300 rpm or less, such as 200 rpm or less, such as 100 rpm or less, such as 75 rpm or less, such as 50 rpm. In some examples, mixing may continue until melting and/or dissolution of the resin (or resins) in the carrier liquid is complete.

In some examples, after combining and heating the resin and the carrier liquid, the mixture is cooled to a temperature below the melting point of the resin, e.g., to room temperature. In some examples, the chargeable particles are removed from the carrier liquid and redispersed in a new portion of carrier liquid, which may be the same or a different carrier liquid.

In some examples, a method of producing a yellow LEP ink composition includes adding a colorant to the combined first resin, second resin, and carrier liquid. In some examples, a method of producing a yellow LEP ink composition includes adding a colorant to the combined first resin, second resin, and carrier liquid to form chargeable particles comprising the resin and the colorant. In some examples, a method of producing a yellow LEP ink composition includes milling a colorant and a resin in the presence of a carrier liquid to form a paste. In some examples, a method of producing a yellow LEP ink composition includes heating and mixing a colorant and a resin in the presence of a carrier liquid to form a paste.

In some examples, the method of producing a yellow LEP ink composition includes adding a charge adjuvant to the combined first resin, second resin, and carrier liquid, and optionally milling. In some examples, a method of producing a yellow LEP ink composition includes adding a charge adjuvant and a colorant to the combined first resin, second resin, and carrier liquid, and optionally milling. In some examples, the method of producing a yellow LEP ink composition includes adding a charge adjuvant to the combined first resin, second resin, colorant, and carrier liquid, and optionally milling.

In some examples, the method of producing the yellow LEP ink composition comprises milling at a milling speed of at least 50 rpm. In some examples, the method of producing the yellow LEP ink composition comprises milling at a milling speed of up to about 600 rpm. In some examples, the method of producing the yellow LEP ink composition includes milling for at least 1 hour, in some examples at least 2 hours. In some examples, the method of producing the yellow LEP ink composition comprises milling for up to about 12 hours. In some examples, the method of producing the yellow LEP ink composition comprises milling at a temperature of at least about 30 ℃, such as at least about 35 ℃, such as at least about 40 ℃, such as at least about 50 ℃. In some examples, the method of producing the yellow LEP ink composition includes milling at a temperature of at least about 50 ℃ for a first period of time, in some examples at least 1 hour, in some examples at least 1.5 hours, then reducing the temperature to a temperature of at least 30 ℃, in some examples at least 35 ℃ and continuing milling for at least 5 hours, in some examples at least 9 hours, in some examples at least 10 hours.

In some examples, a method of producing a yellow LEP ink composition includes adding a charge director to the combined first resin, second resin, and carrier liquid. In some examples, a method of producing a yellow LEP ink composition includes adding a charge director to the combined first resin, second resin, colorant, and carrier liquid. In some examples, a method of producing a yellow LEP ink composition includes adding a charge director to the combined first resin, second resin, charge adjuvant, and carrier liquid. In some examples, a method of producing a yellow LEP ink composition includes adding a charge director to the combined first resin, second resin, colorant, charge adjuvant, and carrier liquid.

In some examples, the method of producing the yellow LEP ink composition includes combining the colorant and the dispersant, and then combining the colorant with other components of the yellow LEP ink composition. In some examples, the method of producing the yellow LEP ink composition includes combining a colorant and a dispersant in a carrier liquid, and then combining the colorant with other components of the yellow LEP ink composition that may include additional carrier liquids.

Examples

Embodiments of the methods and other aspects described herein are illustrated below. Therefore, these embodiments should not be construed as limiting the disclosure, but merely as teaching how to practice embodiments of the disclosure.

Material

Thermoplastic resin

Nucrel 699 copolymers of ethylene and methacrylic acid made with nominal 11 weight percent methacrylic acid (available from DuPont).

AC-5120 copolymer of ethylene and acrylic acid (available from Honeywell) having an acrylic acid content of 15% by weight.

Carrier liquid

Isopar L-fluids comprising a mixture of C11-C13 isoalkanes (Exxon Mobile; CAS number 64742-48-9)

Marcol heavy hydrocarbon oil (available from ExxonMobil).

Pigment (I)

Paliotol yellow D1155 pigment yellow 185 pigment (available from BASF).

Paliotol yellow D1819 pigment yellow 139 pigment (available from BASF).

Ink jet GX-W pigment yellow 74 pigment (available from Clariant).

Toner GX pigment yellow 74 pigment (available from Clariant).

Sunbrite 2725147 pigment yellow 74 pigment (available from Sun Chemical).

Sunbrite 2725157 pigment yellow 74 pigment (available from Sun Chemcial).

Dispersing agent

Solsperse. J560 polymeric amine dispersant based on polyisobutylene succinimide (available from Lubrizol) commercially available as 62 wt% active dispersant in diluent oil

Charge adjuvant

VCA aluminum stearate (available from Fischer Scientific)

Charge directors

NCD (Natural Charge director): KT (natural soybean lecithin in phospholipids and fatty acids), BBP (basic barium Petroleum sulfonate, a barium sulfonate salt of a hydrocarbon alkyl of 21-26 carbons, available from Cemtura ™ cells), and GT (isopropyl dodecyl benzene sulfonate, supplied by Croda @). The composition was 6.6 wt.% KT, 9.8 wt.% BBP, and 3.6 wt.% GT, with the balance (80 wt.%) Isopar L-systems.

Additive agent

DS72 AEROSIL R7200 hydrophobic fumed silica (available from Degusa AG).

HPB: Acumist B-6: polyethylene wax (available from Honeywell).

W12 Polytetrafluoroethylene micronized powder (available from Honeywell).

General procedure-electrophotographic ink compositionPreparation of

Transparent pastes (25 wt% non-volatile solids (NVS)) were formed by combining Nucrel. 699, AC-5120. sup. s (ratio of 4: 1) and Isopar. sup. L1 h in a Ross reactor (Model DPM-2, available from Charles Ross & Son Company-Hauppauge NY) at 130 ℃ and a mixing rate of 50 rpm. The mixing rate was then increased to 70 rpm and mixing was continued for an additional 1.5 hours at 130 ℃. The temperature was then gradually lowered to 25 ℃ over at least 2.5 hours with continued mixing at 70 rpm to form a transparent paste.

The transparent paste was then diluted with additional Isopar @ L and milled in an S1 mill for 12 hours in the presence of VCA (amounts see table 1) and DS72 (amounts see table 1) along with the colorant (amounts see table 1), 1 hour at 58 ℃ and 250 rpm, and then 10.5 hours at 36 ℃ and 250 rpm to form a yellow liquid electrophotographic ink composition.

If dispersants are used (amounts see Table 1), the dispersants and colorants are combined in Isopar @ L by using a Heidolph mixer (400 rpm for 1 hour at room temperature (about 22 ℃) or a high shear mixer (5000 rpm for 30 minutes at room temperature (about 25 ℃) with the temperature increasing to about 50 ℃ during high shear mixing). The clear paste was then diluted with this mixture and milled in the presence of VCA and DS72 in an S1 attritor for 12 hours, at 58 ℃ and 250 rpm for 1 hour, and then at 36 ℃ and 250 rpm for 10.5 hours to form a yellow liquid electrophotographic ink composition.

Prior to printing, the yellow liquid electrophotographic ink composition was diluted with Isopar L and Marcol (0.5 wt% of total liquid) to 2 wt% solids to 3 wt% solids and a polyethylene wax (HPB, amounts see table 1) and micronized PTFE powder (W12, amounts see table 1) were added to the dispersion prior to printing. The charge director (NCD) is then added in the printer in an amount of 5 to 100 mg/g solids.

TABLE 1

PY 185 pigment yellow 185; PY 139 pigment yellow 139; PY 74 pigment yellow 74.

Hue (Hue), lightness and chroma

Hue, lightness and chroma were measured by measuring optical density using an X-rite spectrophotometer and Cartesian/polar color coordinates were derived from spectra under light conditions. The results of these measurements are in table 2. The reference ink was yellow ElectroInk 4.5 (14 wt% pigment loading) to which Solsperse J560 had been added. The example ink contained 22 wt% pigment yellow 74 and 1.1 wt% Solsperse J560.

TABLE 2

	Reference ratio yellow ElectroInk 4.5	Example yellow ink composition
			DMA	0.085	0.057-0.062
Optical Density	1.1	1.2
			Lightness	88.5	90
a*	-6.4	-10.5
			b*	88.5	98.5
Color phase	94	96
			Colour degree	89	100

Four different colorants containing a pigment consisting of pigment yellow 74 were tested. Images printed using each of these colorants have the same hue, lightness, and chroma. In addition, images printed using each of these colorants had improved chroma and lightness and reduced color quality per unit area (DMA) compared to the yellow ElectroInk 4.5 composition.

The yellow ink composition made with pigment yellow 74 obtained from Sun chemical provided a lower dry ink mass per unit area (DMA) at an optical density of 1.4 compared to yellow ink compositions made with pigment yellow 74 from other suppliers.

Second transfer test

Images were printed using a sheet fed series 3 liquid electrophotographic printer. Transfer of example and reference (ElectroInk. sup. 4.5) liquid electrophotographic ink compositions from an intermediate transfer member to a substrate (T2 transfer) were compared when printed at 100% coverage (referred to as solid) and approximately 60% coverage (referred to as gray). Coated and uncoated paper substrates were used. The results are shown in Table 3 below. Images showing differences compared to the reference example image were graded on a scale of-3 to 3, with-3 being much worse than the reference example, 0 being the same as the reference example, and 3 being much better than the reference example.

Y Yellow ElectroInk. RTM.4.5 with a pigment loading of 14% by weight of non-volatile solids.

Y1 example ink formulation wherein the colorant is Sunbrite 2725157, with a pigment loading of 20% by weight of non-volatile solids and no dispersant.

TABLE 3

The example yellow liquid electrophotographic ink formulation with high pigment loading (PL 20 wt%) exhibited better transferability results than the yellow ElectroInk 4.5 composition with only 14 wt% pigment loading. From these results, it can be concluded that the ink properties have changed due to the replacement of the pigment. This will be discussed in connection with the mechanical properties section.

The T2 transfer for the example yellow liquid electrophotographic Ink composition, in which the colorant was Ink jet GX-W (available from Clariant), was also compared to yellow ElectroInk. RTM.4.5. This test showed similar results, i.e. better transfer of T2 for the novel formulation.

Peeling test

Images were printed using a sheet fade series 3 liquid electrophotographic printer at various coverage rates (100%, 200%, 300% and 400%) and peel tests were performed as follows:

an adhesive tape (3M Scotch tape 810) was applied to the thermal transfer fabric. The heavy roll (2 kg) was rolled 4 times over the tape. After waiting 10 minutes, the tape was quickly removed at 180 ° over 2 seconds.

The percentage of ink remaining after removal of the tape was calculated by scanning the printed image before applying the tape and after removing the tape. The change in the number of white pixels and the number of ink covered pixels is then calculated.

FIG. 1 summarizes the results of the peel tests performed on Y and Y1

Y: Yellow ElectroInk™ 4.5

Y1 example ink formulation wherein the colorant was Sunbrite 2725157, with a pigment loading of 20 wt% and no dispersant.

The Y-axis describes the percentage of ink left on the substrate after the tape is removed. Notably, the example yellow liquid electrophotographic ink composition containing the new pigment (Y1) exhibited improved peel resistance at 200%, 300%, and 400% solid coverage on both coated and uncoated substrates.

Mechanical Properties

The mechanical properties of the three yellow liquid electrophotographic ink compositions were studied and compared by tensile strength testing the liquid electrophotographic printed ink compositions using an Instron apparatus. The yellow formulations tested were:

reference ratio 1: Yellow ElectroInk ™ 4.5, 14 wt% pigment loading, containing pigment Yellow 185 and pigment Yellow 139.

Reference example 2A higher pigment load version of the Yellow ElectroInk ™ 4.5 formulation, 23 wt% pigment load, contains pigment Yellow 185 and pigment Yellow 139.

Example yellow liquid electrophotographic ink composition, 20 wt% pigment load, with Sunbrite 2725157 pigment yellow 74 (available from Sun chemical) and 0 wt% dispersant.

Table 4 summarizes the mechanical properties of the three inks.

TABLE 4

Formulations	Pigment loading	Young's modulus [ MPa ]]	Elongation at break [% ]]	Energy of causing breakage [ J]	Tensile stress [ MPa ]]
						Reference ratio 1	14% by weight	78±8	200±15	2.3±0.4	11.6
Reference ratio 2	23% by weight	151±6	126±12	1.9±0.4	12.2
						Examples	20% by weight	74±4	206±11	2.3±0.5	9.4

Increasing the pigment loading of the reference example liquid electrophotographic ink composition from 14 wt% to 23 wt% resulted in the formation of a less elastic printed ink with higher stiffness.

Changing the pigment type to pigment yellow 74 (Sunbrite 2725157) results in a change in the mechanical properties of the ink. The Young's modulus and elongation at break of the Yellow formulation (example) containing pigment Yellow 74 at 20 wt% pigment loading was similar to Yellow ElectroInk. TM.4.5 (see comparative example 1) with a pigment loading of 14 wt% of non-volatile solids. These results may explain the success of the example yellow ink compositions in the T2 transfer test at high pigment loadings.

These results indicate two possible mechanisms of T2 failure at high pigment loadings:

compliance-higher young's modulus leads to a tougher and less flexible printed image, which may lead to poor contact between the image on the intermediate transfer and the substrate.

Lower cohesive force in the film-lower elongation at break leads to increased brittleness of the printed ink composition, reduced plasticization of the film and lower cohesive force of the film.

Summary of results

The compositional differences between the yellow EI 4.5 and the example yellow formulations are discussed below:

pigment Load (PL) -increasing the pigment load from 14 to 20-30 wt% to reduce the dry ink mass per unit area (DMA). By increasing PL to 30 wt%, chroma is 113 (significantly higher than chroma of ElectroInk 4.5, which is 90), which expands the color gamut. Lower PL (e.g., 20 wt% or even 14 wt%) reduces cost per page, but maintains higher chroma than ElectroInk 4.5 (14 wt% NVS pigment).

Secondary pigment-elimination of secondary pigments increases chroma and enlarges the color gamut.

Pigment type-pigment type replacement leads to better ink transferability at high pigment loadings (T2) and better resistance to peeling.

Addition of dispersant-Solsperse. J560 dispersant improves color development by better dispersing the pigment particles to yield improved color properties. Further, a reduction in DMA may also be achieved.

While the compositions, methods, and other aspects have been described with reference to certain embodiments, those skilled in the art will recognize that various modifications, changes, omissions, and substitutions can be made without departing from the spirit of the disclosure. It is intended that the compositions, methods, and other aspects be limited by the scope of the following claims. Features of any dependent claim may be combined with features of any other dependent claim and any independent claim, unless indicated otherwise.