Aqueous inkjet ink compositions made from monodisperse latexes

Abstract

To provide aqueous inkjet ink compositions having improved stability and printing performance.SOLUTION: In an embodiment, a composition comprises: water; resin particles; and a colorant, wherein the resin particles comprise a polymerization product of reactants comprising a monomer, an acidic monomer, a multifunctional monomer, and a reactive surfactant, the resin particles having a D(z,ave) of about 150 nm or less, a D(v,90) of less than about 200 nm, and a polydispersity index (PDI) of about 0.050 or less. Methods of forming and using the aqueous inkjet ink compositions are also provided.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application is a continuation-in-part of U.S. Patent Application No. 17 / 102,596, filed November 24, 2020, the entire contents of which are incorporated herein by reference. [Background technology]

[0002] Latexes for aqueous inkjet ink compositions are often synthesized by emulsion or microemulsion polymerization of hydrophobic monomers in water. Large amounts of surfactants, such as sodium dodecyl sulfonate (SDS), are often used to make the resin particles in the latex small and colloidally stable. Excess surfactant in the resulting latex can cause problems in formulating aqueous inkjet ink compositions, such as foaming and reduced surface tension. Removal of excess surfactant also adds cost, complexity, and time, and can lead to colloidal instability. In addition, the resin particles in the resulting latex typically have a broad size distribution. Even a small number of large resin particles can cause particle settling and nozzle clogging during printing of aqueous inkjet ink compositions formed from the latex. Summary of the Invention [Problem to be solved by the invention]

[0003] Aqueous inkjet ink compositions generally contain water, a water-dispersible pigment, a hydrophilic solvent, and a binder resin. The binder resin may be provided by a specific latex, as described above. Latex is useful because it can form a water-permeable film to protect the colorant in an image printed from the aqueous inkjet ink composition. However, the addition of latex to an aqueous inkjet ink composition imposes a level of complexity and tends to impair printing behavior, such as jet instability, jet latency, and nozzle clogging. The use of latex in an aqueous inkjet ink composition also reduces the shelf life of the composition.

[0004] The present disclosure provides methods for forming monodisperse latex. Embodiments of the methods provide for the formation of monodisperse latex particles having small size and narrow size distribution (e.g., D (z、ave) ≦150nm, D (v、90) <200 and PDI≦0.05), resin particles can be achieved. This is believed to contribute, at least in part, to the greatly improved stability and print performance of aqueous ink-jet ink compositions formed from the latex. Monodisperse latex and aqueous ink-jet ink compositions are also encompassed by the present disclosure.

[0005] In one embodiment, such a composition comprises water, resin particles, and a colorant, the resin particles comprising the polymerization product of reactants including a monomer, an acidic monomer, a multifunctional monomer, and a reactive surfactant, the resin particles having a D of about 150 nm or less. (z、ave) , D less than about 200 nm (v、90) and a polydispersity index (PDI) of about 0.050 or less. Methods of forming and using the aqueous ink-jet ink composition are also provided.

[0006] Other principal features and advantages of the present disclosure will become apparent to those skilled in the art upon review of the following drawings, detailed description, and appended claims. [Brief explanation of the drawings]

[0007] Exemplary embodiments of the present disclosure will now be described with reference to the accompanying drawings.

[0008] [Figure 1] FIG. 1 shows the size distribution of resin particles in a monodisperse latex formed according to an exemplary embodiment of the present method.

[0009] [Figure 2] FIG. 2 shows the size distribution of resin particles of another monodisperse latex formed according to an exemplary embodiment of the present method.

[0010] [Figure 3] 3 shows a scanning transmission electron microscope (STEM) image of a dried, monodisperse latex formed according to an exemplary embodiment of the present method, which shows localized crystallization and demonstrates the ability to form three-dimensional (3D) photonic crystals. DETAILED DESCRIPTION OF THE INVENTION

[0011] Monodisperse latex

[0012] In one aspect, a method for forming a monodisperse latex is provided. The latex comprises resin particles synthesized from certain monomers by this method, which are further described below. The following monomers and combinations thereof can be used (e.g., the use of "(meth)" as in "(meth)acrylate" refers to both acrylate and methacrylate): styrene; alkyl (meth)acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, dodecyl acrylate, n-octyl acrylate, 2-chloroethyl acrylate, methyl methacrylate, ethyl methacrylate, and butyl methacrylate; β-carboxyethyl acrylate (β-CEA), phenyl acrylate, methyl alpha chloroacrylate; butadiene; isoprene; methacrylonitrile; acrylonitrile; vinyl methyl ether. vinyl ethers such as vinyl ether, vinyl isobutyl ether, and vinyl ethyl ether; vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate, and vinyl butyrate; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and methyl isopropenyl ketone; vinylidene halides such as vinylidene chloride and vinylidene chlorofluoride; N-vinylindole; N-vinylpyrrolidone; methacrylates; acrylamide; methacrylamide; vinylpyridine; vinylpyrrolidone; vinyl-N-methylpyridinium chloride; vinylnaphthalene; p-chlorostyrene; vinyl chloride; vinyl bromide; vinyl fluoride; ethylene; propylene; butylene; and isobutylene. In embodiments, the monomers used to form the resin particles of the latex include styrene and an alkyl acrylate.

[0013] Acidic monomers may be used to form monodisperse latex resin particles, including (meth)acrylic acid monomers, sulfonic acid monomers, sulfonate monomers, and combinations thereof. Exemplary acidic monomers include acrylic acid, methacrylic acid, ethacrylic acid, dimethylacrylic acid, maleic anhydride, maleic acid, styrenesulfonic acid, vinylsulfonate, cyanoacrylic acid, vinylacetic acid, allylacetic acid, ethylidineacetic acid, propylidineacetic acid, crotonic acid, fumaric acid, itaconic acid, sorbic acid, angelic acid, cinnamic acid, styrylacrylic acid, citraconic acid, glutaconic acid, aconitic acid, phenylacrylic acid, acryloxypropionic acid, vinylbenzoic acid, N-vinylsuccinimide ... Examples of suitable acidic monomers include acrylic acid, mesaconic acid, methacryloylalanine, acryloylhydroxyglycine, sulfoethylmethacrylic acid, sulfopropylacrylic acid, styrenesulfonic acid, sulfoethylacrylic acid, 2-methacryloyloxymethane-1-sulfonic acid, 3-methacryloyloxypropane-1-sulfonic acid, 3-(vinyloxy)propane-1-sulfonic acid, ethylenesulfonic acid, vinylsulfuric acid, 4-vinylphenylsulfuric acid, ethylenephosphonic acid, vinylphosphoric acid, vinylbenzoic acid, 2-acrylamido-2-methyl-1-propanesulfonic acid, and combinations thereof. These acidic monomers also include salts thereof, such as salts of sulfonic acid.

[0014] In embodiments, the two different acidic monomers each have a different pK a The pK of two different acidic monomers is used to form monodisperse latex resin particles with a The values ​​may differ from one another by at least 2 units, at least 3 units, at least 4 units, or at least 5 units. In embodiments, the two different acidic monomers are present in the monomer emulsion used to form the resin particles in a weight ratio ranging from 0.1 to 10, including ranges from 0.5 to 8 and 1 to 6. In embodiments, the two different types of acidic monomers used to form the resin particles comprise methacrylic acid and sulfonic acid.

[0015] Hydrophilic monomers can be used to form monodisperse latex resin particles. The term "hydrophilic monomer" is distinct from the "acidic monomer" described above. That is, while the selected acidic monomer may also be hydrophilic, these terms refer to different, chemically distinct species of monomer. Hydrophilic monomers are generally monofunctional, i.e., contain a single polymerizable group. Exemplary hydrophilic monomers include hydroxyethyl (meth)acrylate, n-hydroxyethyl (meth)acrylamide, hydroxypropyl (meth)acrylate, and hydroxypropyl (meth)acrylamide, ethylene glycol (meth)acrylate, propylene glycol (meth)acrylate, poly(ethylene glycol) (meth)acrylate having a molecular weight of 200 g / mol to 2000 g / mol, and poly(propylene glycol) (meth)acrylate having a molecular weight of 200 g / mol to 2000 g / mol, and combinations thereof. In embodiments, the hydrophilic monomer used to form the resin particles includes poly(propylene glycol) methacrylate.

[0016] Multifunctional monomers can be used to form monodisperse latex resin particles, i.e., those containing two or more polymerizable groups (e.g., two, three, or four). These are useful because they promote crosslinking within the resin particles. Exemplary multifunctional monomers include difunctional monomers such as poly(ethylene glycol) di(meth)acrylate, e.g., poly(ethylene glycol) diacrylate having a molecular weight of 200 g / mol to 2000 g / mol. These difunctional monomers may also be considered hydrophilic, as described above. Other hydrophilic bifunctional monomers include diacrylate compounds bonded to alkyl chains containing ether bonds, such as diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol #400 diacrylate, polyethylene glycol #600 diacrylate, and dipropylene glycol diacrylate, as well as compounds obtained by substituting methacrylate for the acrylate of these compounds; diacrylate compounds bonded to chains containing aromatic groups and ether bonds, such as polyoxyethylene (2)-2,2-bis(4-hydroxyphenyl)propane diacrylate and polyoxyethylene (4)-2,2-bis(4-hydroxyphenyl)propane diacrylate, as well as compounds obtained by substituting methacrylate for the acrylate of these compounds. Other exemplary difunctional monomers include diene compounds such as isoprene and butadiene, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene, diacrylate compounds bonded with alkyl chains such as ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, 1,10-dodecanediol diacrylate, and neopentyl glycol diacrylate, as well as compounds obtained by substituting methacrylate for the acrylate of these compounds.Polyfunctional monomers include pentaerythritol triacrylate, trimethylolmethane triacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, oligoester acrylates, and the like, and compounds obtained by substituting the acrylate of these compounds with methacrylate.

[0017] Reactive surfactants can be used to form monodisperse latex resin particles. Suitable reactive surfactants contain polymerizable (and therefore reactive) groups so that they can be incorporated into the resin particles. Exemplary reactive surfactants include anionic ether sulfate reactive surfactants, such as those in the commercially available Hitenol BC series, including Hitenol BC10-25. Other suitable reactive surfactants include polyoxyethylene alkyl phenyl ether ammonium sulfates, including Hitenol BC-10, BC-20, BC-2020, BC-30; polyoxyethylene styrenated phenyl ether ammonium sulfates, including Hitenol AR-10, AR-20, AR10-25, AR-2020; nonionic polyoxyethylene alkyl phenyl ethers, including Noigen RN-10, RN-20, RN-30, RN-40, RN-5065; and reactive surfactants available from Ethox, including E-sperse RX-201, RX-202, RX-203, RS-1596, RS-1616, RS-1617, RS-1618, RS-1684.

[0018] A chain transfer agent can be used to form a monodisperse latex. The chain transfer agent can be a mercaptan or a thiol. Suitable chain transfer agents include n-dodecylmercaptan (NDM), n-dodecanethiol (DDT), tert-dodecylmercaptan, 1-butanethiol, 2-butanethiol, octanethiol, and combinations thereof. Halocarbons such as carbon tetrabromide, carbon tetrachloride, and combinations thereof can be used as chain transfer agents.

[0019] When forming a monodisperse latex, any of the monomers described above can be used in a monomer emulsion containing a solvent. Water is generally used as the solvent, but water-soluble or water-miscible organic solvents (e.g., ethanol) can also be included. The types of monomers and their relative amounts can be selected to adjust the properties of the resin particles / latex. However, the following amounts have been found to be useful for achieving resin particles with small size and narrow size distribution:

[0020] Acidic monomers may be used in the monomer emulsion in amounts ranging from 1.5% to 15% by weight, where weight % is the total weight of acidic monomers divided by the total weight of monomers in the monomer emulsion excluding reactive surfactants. * (Refers to 100). This range includes 5% to 10% by weight. As mentioned above, different pK a Two different types of acidic monomers having the same weight ratio may be used in the weight ratios described above. Hydrophilic monomers may be used in the monomer emulsion in an amount ranging from 0% to 5% by weight. (Wt% has a similar meaning to that described for acidic monomers.) This range includes 0.1% to 5% by weight, and 1% to 5% by weight. Multifunctional monomers, including difunctional monomers, may be used in the monomer emulsion in an amount ranging from 0.01 to 5% by weight, 0.1% to 5% by weight, or 0.1% to 1% by weight. (Wt% has a similar meaning to that described for acidic monomers.) Other monomers (e.g., styrene, alkyl (meth)acrylate) may be present in an amount ranging from 70% to 97% by weight. (Wt% has a similar meaning to that described for acidic monomers.) This range includes 75% to 90% by weight.

[0021] Combined, the amount of acidic monomer, hydrophilic monomer, and multifunctional monomer (e.g., hydrophilic multifunctional monomer) may be present in the monomer emulsion in the range of 1.5% to 12% by weight, where weight % is the total weight of acidic monomer, hydrophilic monomer, and multifunctional monomer divided by the total weight of monomers in the monomer emulsion excluding reactive surfactants. * 100.) This range includes 2% to 12% by weight, and 5% to 10% by weight.

[0022] The reactive surfactants may be used in the monomer emulsion in an amount ranging from 1.5% to 6.5% by weight, where weight % is the total weight of reactive surfactants / total weight of monomers in the monomer emulsion, including reactive surfactant monomers. * 100.) This range includes 1.5% to 5% by weight.

[0023] The chain transfer agent may be present in the monomer emulsion and may be used in various suitable amounts, for example, from 0.25% to 2.5% by weight, where weight % is the total weight of chain transfer agent / total weight of monomers in the monomer emulsion excluding reactive surfactants. * It points to 100.)

[0024] In embodiments, the monomer emulsion comprises (or consists of) a solvent (e.g., water), styrene, an alkyl acrylate (e.g., butyl acrylate), an acidic monomer, a multifunctional monomer (e.g., a difunctional monomer), a reactive surfactant, and a chain transfer agent. In such embodiments, various monomers of one type or different types may be used. Similarly, one type or different types of solvents and / or one type or different types of chain transfer agents may be used. In embodiments, the monomer emulsion comprises (or consists of) a solvent (e.g., water), styrene, an alkyl acrylate (e.g., butyl acrylate), methacrylic acid, a hydrophilic monomer (e.g., poly(propylene glycol) methacrylate), a multifunctional monomer (e.g., a difunctional monomer), a reactive surfactant, and a chain transfer agent. In embodiments, the monomer emulsion comprises (or consists of) a solvent (e.g., water), styrene, an alkyl acrylate (e.g., butyl acrylate), two different types of acidic monomers (e.g., methacrylic acid and sulfonic acid), a difunctional monomer (e.g., poly(ethylene glycol) diacrylate), a reactive surfactant, and a chain transfer agent. In any of these embodiments, various amounts of monomers and chain transfer agents may be used, as described above. The remainder may consist of solvent.

[0025] In at least some embodiments, the monomer emulsion does not have (i.e., does not contain) a surfactant. Here, "surfactant" refers to non-reactive, non-polymerizable anionic surfactants such as sodium dodecyl sulfate (SDS), sodium dodecylbenzenesulfonate, sodium dodecylnaphthalene sulfate; dialkylbenzene alkyl nitrates; palmitic acid; alkyldiphenyloxide disulfonates; and branched sodium dodecylbenzenesulfonate. "Surfactant" also refers to non-reactive, non-polymerizable cationic surfactants such as alkylbenzyldimethyl ammonium chloride, dialkylbenzene alkyl ammonium chloride, lauryl trimethyl ammonium chloride, alkylbenzylmethyl ammonium chloride, alkylbenzyldimethyl ammonium bromide, benzalkonium chloride, cetyl pyridinium bromide, trimethyl ammonium bromide, halide salts of quaternized polyoxyethyl alkylamines, and dodecylbenzyl triethyl ammonium chloride. "Surfactant" also refers to non-reactive non-polymerizable nonionic surfactants such as polyoxyethylene cetyl ether, polyoxyethylene lauryl ether, polyoxyethylene octyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene oleyl ether, polyoxyethylene sorbitan monolaurate, polyoxyethylene stearyl ether, polyoxyethylene nonylphenyl ether, dialkylphenoxypoly(ethyleneoxy)ethanol, and block copolymers of polyethylene oxide and polypropylene oxide. Thus, the monomer emulsion may not have (i.e., does not contain) any of these surfactants.

[0026] The method for forming a monodisperse latex includes adding any of the monomer emulsions described above to a reactive surfactant solution at a feed rate over a period of time. The reactive surfactant solution includes a solvent and a reactive surfactant. Any of the solvents and any of the reactive surfactants described above may be used. One or different types of solvents and / or reactive surfactants may be used. The reactive surfactant in the reactive surfactant solution may be the same or different type compared to the reactive surfactant that may be present in the monomer emulsion. The reactive surfactant solution may further include a buffer. Various buffers such as sodium bicarbonate, sodium carbonate, and ammonium hydroxide may be used. The reactive surfactant may be used in an amount ranging from 1% to 10% by weight, where weight % is calculated as (total weight of reactive surfactant) / (total weight of reactive surfactant solution). * (The percentage by weight refers to 100.) This range includes 2% to 5% by weight. Buffers may be used in amounts ranging from 0.25% to 2.5% by weight. (Percent by weight has the same meaning as described above.)

[0027] An initiator may be included in the reactive surfactant solution. Alternatively, a separate initiator solution containing the initiator and one of the solvents described above may be formed, and the separate initiator solution is added to the reactive surfactant solution. The separate initiator solution may be added before adding the monomer emulsion. One or different types of solvents and / or initiators may be used. Examples of suitable initiators include water-soluble initiators such as ammonium persulfate (APS), sodium persulfate, and potassium persulfate, as well as organic-soluble initiators including organic peroxides and azo compounds, including Vazo peroxides such as VAZO 64™, 2-methyl-2-2'-azobispropanenitrile, VAZO 88™, and 2-2'-azobisisobutylamide anhydride, and combinations thereof.Other water-soluble initiators that can be used include azoamidine compounds such as 2,2'-azobis(2-methyl-N-phenylpropionamidine) dihydrochloride, 2,2'-azobis[N-(4-chlorophenyl)-2-methylpropionamidine] dihydrochloride, 2,2'-azobis[N-(4-hydroxyphenyl)-2-methyl-propionamidine] dihydrochloride, 2,2'-azobis[N-(4-amino-phenyl)-2-methylpropionamidine] tetrahydrochloride, 2,2'-azobis[2-methyl-N(phenylmethyl)propionamidine] dihydrochloride, 2,2'-azobis[2-methyl-N-2-propenylpropionamidine] dihydrochloride, 2,2'-azobis[N-(2-hydroxy-ethyl)-2-methylpropionamidine] amidine] dihydrochloride, 2,2'-azobis[2(5-methyl-2-imidazolin-2-yl)propane] dihydrochloride, 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, 2,2'-azobis[2-(4,5,6,7-tetrahydro-1H-1,3-diazepin-2-yl)propane] dihydrochloride, 2,2'-azobis[2-( Examples of initiators include 2,2'-azobis[2-(5-hydroxy-3,4,5,6-tetrahydropyrimidin-2-yl)propane]dihydrochloride, 2,2'-azobis{2-[1-(2-hydroxyethyl)-2-imidazolin-2-yl]propane}dihydrochloride, and combinations thereof. The initiator may be used in an amount ranging from 0.1% to 2.5% by weight, where weight % is the total weight of the initiator divided by the total weight of the reactive surfactant solution. * It points to 100.)

[0028] In embodiments, the reactive surfactant solution comprises (or consists of) a solvent (e.g., water), a reactive surfactant, and optionally one or more of an initiator and a buffer. In such embodiments, one or different types of these components may be used. In any of these embodiments, the amounts of reactive surfactant, initiator, and buffer may be used as described above. The remainder may consist of solvent. In at least some embodiments, the reactive surfactant solution does not have (i.e., does not contain) any of the surfactants described above. In at least some embodiments, the reactive surfactant solution does not have (i.e., does not contain) any monomers other than the reactive surfactant monomers present in the solution.

[0029] The addition of the monomer emulsion to the reactive surfactant solution can be carried out under an inert gas (e.g., nitrogen) and at an elevated temperature (e.g., above room temperature, such as a temperature in the range of 50° C. to 90° C.). This can be accomplished by purging with an inert gas and heating the reactive surfactant solution prior to adding the monomer emulsion and continuing during the addition of the monomer emulsion.

[0030] As described above, the monomer emulsion is added at a feed rate over a period of time. In the presence of an initiator, the monomers in the monomer emulsion undergo a polymerization reaction to form monodisperse latex resin particles. The feed rate is sufficiently slow so that the polymerization is carried out under "monomer starvation" conditions. This means that the feed rate is equal to or less than the rate of the polymerization reaction, for example, the rate between styrene and acrylate monomers. Exemplary feed rates include those in the range of 1 mL / min to 10 mL / min, based on a 1 L total reaction volume. Exemplary durations include those in the range of 60 minutes to 600 minutes. After the monomer emulsion is added, the polymerization can be continued for an additional period of time. Exemplary additional durations include those in the range of 1 hour to 18 hours. The addition of the monomer emulsion and the subsequent polymerization can be carried out under inert gas and at elevated temperatures. Optionally, the formed latex can be processed by standard techniques such as coagulation, dissolution, and precipitation, filtration, washing, or drying. When the solvent / water is removed from the latex, for example by drying, the dried latex still contains resin particles that can be used to form the aqueous inkjet ink compositions described below. Thus, any of the disclosed aqueous inkjet ink compositions can simply contain resin particles of any of the disclosed latexes.

[0031] It should be noted that, in at least embodiments, the present method does not involve the use of resin seeds in forming the monodisperse latex resin particles. This is in contrast to existing processes that use resin seeds to initiate and stabilize polymerization. Thus, in such embodiments, neither the monomer emulsion nor the reactive surfactant solution contains such resin seeds. The polymerization reaction that forms the resin particles does not involve such resin seeds. Similarly, in at least embodiments, the present method does not involve the use of any of the surfactants described above (other than the reactive surfactant monomers).

[0032] The method may further include forming a monomer emulsion, forming a reactive surfactant solution, and / or forming an initiator solution, each of which may be formed by combining and mixing the desired components in the desired amounts.

[0033] As described above, the monodisperse latex formed by the present method comprises resin particles having a small size and narrow distribution. The composition of the resin particles depends on the selection of monomers and their relative amounts, as well as the polymerization reaction between the selected monomers to produce the polymerization product described above. Therefore, various compositions are encompassed based on the above description, including those based on various polymerization products of reactants including combinations of various monomers. However, in embodiments, the resin particles comprise (or consist of) the polymerization product (e.g., copolymer) of reactants including styrene, an alkyl acrylate (e.g., butyl acrylate), an acidic monomer, a multifunctional monomer (e.g., a difunctional monomer), and a reactive surfactant. In such embodiments, one type or different types of various monomers may be present. In embodiments, the resin particles comprise (or consist of) the polymerization product of reactants including styrene, an alkyl acrylate (e.g., butyl acrylate), methacrylic acid, a hydrophilic monomer (e.g., poly(propylene glycol) methacrylate), a multifunctional monomer (e.g., a difunctional monomer), and a reactive surfactant. In embodiments, the resin particles comprise (or consist of) the polymerization product of reactants including styrene, an alkyl acrylate (e.g., butyl acrylate), two different types of acidic monomers (e.g., methacrylic acid and sulfonic acid), a difunctional monomer (e.g., poly(ethylene glycol) diacrylate), and a reactive surfactant. In each of these embodiments, an initiator may be incorporated at the beginning and end of each polymer chain in the resin particles. In each of these embodiments, the resin may be crosslinked due to the polyfunctional / difunctional monomer. In each of these embodiments, the monomer may be present in the resin particles in the amounts described above.

[0034] The resin particles of the monodisperse latex of the present invention can be characterized by their size, which is measured using a nanoparticle analyzer such as a Malvern Nano Zetasizer. (z、ave) In an embodiment, the D-value may be reported as (z、ave) is 150 nm or less, 120 nm or less, 110 nm or less, 100 nm or less, or in the range of 60 nm to 150 nm or 60 nm to 100 nm.

[0035] Similarly, the resin particles of the monodisperse latex of the present invention can be characterized by their size distribution. The size distribution may be reported as a polydispersity index (PDI) measured using a nanoparticle analyzer such as a Malvern Nano-ZS. In embodiments, the PDI is 0.1 or less, 0.050 or less, 0.025 or less, 0.010 or less, 0.005 or less, or in the range of 0.001 to 0.1.

[0036] Due to their small size and narrow size distribution, the resin particles of the monodisperse latexes of the present invention can be further characterized as being free of (i.e., free of) large particles, such as D1 < 200 nm, D1 < 175 nm, or D1 < 150 nm. (v、90) It can be proved by the value.

[0037] The small size and narrow size distribution of the monodisperse latex of the present invention can be further evidenced by its ability to form three-dimensional (3D) photonic crystals when the solvent is removed from the latex (i.e., dried). Such crystal formation is possible due to the uniform size of the resin particles. Localized crystallization and the ability to form 3D photonic crystals can be confirmed using scanning tunneling electron microscopy (STEM). (See Figure 3.) Controlled heating can be used to achieve 3D photonic crystals.

[0038] Aqueous inkjet ink composition

[0039] Any of the monodisperse latexes described above may be used to provide an aqueous inkjet ink composition. As noted above, the small size and narrow distribution of the resin particles in the latex are believed to contribute, at least in part, to the significantly improved stability and print performance of the aqueous inkjet ink composition. The latex may be present in the aqueous inkjet ink composition in an amount ranging from 1% to 10% by weight, where % by weight is the total weight of the dry latex divided by the total weight of the aqueous inkjet ink composition. * (The percentages refer to 100.) This range is inclusive of 5% to 10% by weight. Various other components can be used to form the aqueous inkjet ink compositions described below.

[0040] Solvent System

[0041] The aqueous inkjet ink composition includes a water-based solvent system. The solvent system can consist solely of water or can include a mixture of water and water-soluble and / or water-miscible organic solvents. The water-soluble and water-miscible organic solvents may be referred to herein as co-solvents or humectants. Suitable such organic solvents include aliphatic alcohols, aromatic alcohols, diols, glycol ethers, polyglycol ethers, long-chain alcohols, primary aliphatic alcohols, secondary aliphatic alcohols, 1,2-alcohols, 1,3-alcohols, 1,5-alcohols, ethylene glycol alkyl ethers, propylene glycol alkyl ethers, methoxylated glycerol, and ethoxylated glycerol. Illustrative examples include ethylene glycol, propylene glycol, diethylene glycol, glycerin, dipropylene glycol, trimethylolpropane, 1,2-hexanediol, 1,5-pentanediol, 2-methyl-1,3-propanediol, 2-ethyl-2-hydroxymethyl-1,3-propanediol, 3-methoxybutanol, 3-methyl-1,5-pentanediol, 1,3-propanediol, 1,4-butanediol, and 2,4-heptanediol.Other suitable solvents include amides, ethers, urea, substituted ureas such as thiourea, ethylene urea, alkyl ureas, alkylthioureas, dialkyl ureas, and dialkylthioureas, carboxylic acids and their salts such as 2-methylpentanoic acid, 2-ethyl-3-propylacrylic acid, 2-ethyl-hexanoic acid, 3-ethoxypropionic acid, esters, organic sulfides, organic sulfoxides, sulfones (such as sulfolane), carbitol, butyl carbitol, cellusolve, ethers, thiazolinone ... Examples of suitable organic solvents include propylene glycol monomethyl ether, ether derivatives, hydroxyethers, amino alcohols, ketones, N-methylpyrrolidinone, 2-pyrrolidinone, cyclohexylpyrrolidone, amides, sulfoxides, lactones, polyelectrolytes, methylsulfonylethanol, imidazole, 1,3-dimethyl-2-imidazolidinone, betaine, sugars such as 1-deoxy-D-galactitol, mannitol, inositol, substituted and unsubstituted formamides, and substituted and unsubstituted acetamides. Combinations of these organic solvents may also be used.

[0042] Suitable water-soluble and / or water-miscible organic solvents include glycols, which are hydrocarbons having carbon atoms of 4 to 7. Examples of such glycols include 1,2-pentanediol, 1,2-hexanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,3-butanediol, 1,2-butanediol, 2,4-pentanediol, 1,7-heptanediol, 3-methyl-1,5-pentanediol, trimethylolpropane, ethyleneurea, 1,2,6-hexanetriol, 1,2,3-butanetriol, sorbitol, urea, diethylene glycol, 1,2,4-butanetriol, glycerol, diglycerol, triethylene glycol, polyethylene glycol 200, and polyethylene glycol 600.

[0043] In embodiments, the solvent system comprises water, a 1,2-alcohol (eg, 1,2-hexanediol), a glycol (eg, propylene glycol), and glycerol.

[0044] In solvent systems containing water and organic solvents, the weight ratio of water to organic solvent, as well as the types and relative amounts of different organic solvents, may be selected to achieve certain properties of the aqueous inkjet ink composition, such as desired surface tension, viscosity, etc. In embodiments, the weight ratio of water to organic solvent is 90:10 to 51:49. When more than one organic solvent is used, these weight ratios refer to the total amount of organic solvent. Because water may be present in latexes, colorants, etc., these weight ratios refer to the total amount of water.

[0045] Similarly, various total amounts of solvent system can be used in the aqueous ink-jet ink composition. In embodiments, the solvent system is present in an amount of 50% to 95% by weight, 60% to 90% by weight, or 65% to 90% by weight, where wt % is the total weight of the solvent system divided by the total weight of the aqueous ink-jet ink composition. * In embodiments, the total amount of water present is at least 50% by weight, at least 60% by weight, at least 80% by weight, or in the range of 50% to 95% by weight (where wt % is the total weight of water / total weight of the aqueous inkjet ink composition). * It points to 100.)

[0046] Water-soluble resin

[0047] Water-soluble resins may be used in aqueous inkjet ink compositions. The type and amount may also be selected to achieve a desired viscosity. Exemplary water-soluble resins include polyethylene glycol and polyvinylpyrrolidone. The molecular weight of the water-soluble resin may range from 1,000 g / mol to 10,000 g / mol. However, it has been surprisingly found that at least some embodiments of aqueous inkjet ink compositions are sensitive to the type and molecular weight of the water-soluble resin. This finding is further described in the examples below. In embodiments, the water-soluble resin is polyethylene glycol having a molecular weight in the range of 3,000 g / mol to 9,000 g / mol, 3,000 g / mol to 7,000 g / mol, 3,000 g / mol to 5,000 g / mol, or 4,000 g / mol. These molecular weight values ​​can be determined using gel permeation chromatography. In embodiments, the amount of water-soluble resin is selected so that the total solids content of the aqueous inkjet ink composition (generally provided by the latex, water-soluble resin, and colorant) is 5% to 15%, 6% to 12%, or 7% to 10% by weight, where weight % is the total weight of solids / total weight of the aqueous inkjet ink composition. * It points to 100.)

[0048] The aqueous inkjet ink composition may further include other binder resins, including acrylic polymers such as styrene-acrylic copolymers and vinylpyrrolidone copolymers, urethane or polyurethane dispersions, and acrylic-urethane hybrid dispersions. Specific binder resins that can be used include those available from Johnson Polymers (BASF), such as Joncryl, including those named Joncryl 661, Joncryl 8003, Joncryl 8078, Joncryl 8082, Joncryl 537, Joncryl H538, Joncryl H538, and HPD 71E. Other exemplary water-soluble resins include Rhoplex I-1955, Rhoplex I-2426D, Rhoplex I-62, Rhoplex I-98, and Rhoplex E-1691, available from Rhohm & Haas. Others include Lucidene 190, Lucidene 400, and Lucidene 243 available from DSM Corporation; NeoCryl A-1110, NeoCryl A-2092, NeoCryl A-639, NeoRad R-440, NeoRad R-441, NeoRez N-55, 972, PVP K-15, PVP K-30, PVP K-60, PVP K-85 available from ISP; Ganex P-904LC, PVP / VA W-63.

[0049] coloring agent

[0050] The aqueous inkjet ink composition may include a colorant. Colorants include pigments, dyes, and combinations thereof. Examples of suitable dyes include anionic dyes, cationic dyes, nonionic dyes, and zwitterionic dyes. Specific examples of suitable dyes include food dyes such as Black Food No. 1, Black Food No. 2, Red Food No. 40, Blue Food No. 1, and Yellow Food No. 7, FD&C dyes, Acid Black Dye (Nos. 1, 7, 9, 24, 26, 48, 52, 58, 60, 61, 63, 92, 107, 109, 118, 119, 131, 140, 155, 156, 172, and 194), Acid Red Dye (Nos. 1, 8, 32, 35, 37, 52, 56, 58, 60, 61, 63, 92, 107, 109, 118, 119, 131, 140, 155, 156, 172, and 194), and Acid Red Dye (Nos. 1, 8, 32, 35, 37, 52, 56, 58, 60, 61, 63, 92, 107, 109, 118, 119, 131, 140, 155, 156, 172, and 194). 57, 92, 115, 119, 154, 249, 254, 256), Acid Blue Dyes (No. 1, 7, 9, 25, 40, 45, 62, 78, 80, 92, 102, 104, 113, 117, 127, 158, 175, 183, 193, 209), Acid Yellow Dyes (No. 3, 7, 17, 19, 23, 25, 29, 38, 42, 49, 59, 61, 72, 73, 114, 128, 151), Direct Black Dyes (No. 4, 14, 17 , 22, 27, 38, 51, 112, 117, 154, 168), Direct Blue Dyes (No. 1, 6, 8, 14, 15, 25, 71, 76, 78, 80, 86, 90, 106, 108, 123, 163, 165, 199, 226), Direct Red Dyes (No. 1, 2, 16, 23, 24, 28, 39, 62, 72, 236), Direct Yellow Dyes (No. 4, 11, 12, 27, 28, 33, 34, 39, 50, 58, 86, 100, Examples of reactive dyes include reactive dyes such as reactive red dyes (Nos. 106, 107, 118, 127, 132, 142, 157), reactive red dyes (Nos. 4, 31, 56, 180), reactive black dyes (No. 31), and reactive yellow dyes (No. 37), anthraquinone dyes, monoazo dyes, disazo dyes, phthalocyanine derivatives including various phthalocyanine sulfonates, aza(18)annulenes, formazan copper complexes, and triphenodioxazines.

[0051] Examples of suitable pigments include black pigments, cyan pigments, magenta pigments, and yellow pigments. Pigments can be organic or inorganic particles. Suitable inorganic pigments include carbon black. However, other inorganic pigments such as cobalt blue (CoO-Al2O3), chrome yellow (PbCrO4), and iron oxides may also be suitable. Suitable organic pigments include azo pigments, such as diazo pigments and monoazo pigments, polycyclic pigments (e.g., phthalocyanine pigments, such as phthalocyanine blue and phthalocyanine green), perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, pyranthrone pigments, and quinophthalone pigments), insoluble dye chelates (e.g., basic dye chelates and acid dye chelates), nitro pigments, nitroso pigments, and anthanthrone pigments, such as PR168. Representative examples of phthalocyanine blues and greens include copper phthalocyanine blue, copper phthalocyanine green, and their derivatives (Pigment Blue 15, Pigment Green 7, and Pigment Green 36). Representative examples of quinacridones include Pigment Orange 48, Pigment Orange 49, Pigment Red 122, Pigment Red 192, Pigment Red 202, Pigment Red 206, Pigment Red 207, Pigment Red 209, Pigment Violet 19, and Pigment Violet 42. Representative examples of anthraquinones include Pigment Red 43, Pigment Red 194, Pigment Red 177, Pigment Red 216, and Pigment Red 226. Representative examples of perylenes include Pigment Red 123, Pigment Red 149, Pigment Red 179, Pigment Red 190, Pigment Red 189, and Pigment Red 224. Representative examples of thioindigoids include Pigment Red 86, Pigment Red 87, Pigment Red 88, Pigment Red 181, Pigment Red 198, Pigment Violet 36, and Pigment Violet 38.Representative examples of heterocyclic yellows include Pigment Yellow 1, Pigment Yellow 3, Pigment Yellow 12, Pigment Yellow 13, Pigment Yellow 14, Pigment Yellow 17, Pigment Yellow 65, Pigment Yellow 73, Pigment Yellow 74, Pigment Yellow 90, Pigment Yellow 110, Pigment Yellow 117, Pigment Yellow 120, Pigment Yellow 128, Pigment Yellow 138, Pigment Yellow 150, Pigment Yellow 151, Pigment Yellow 155, and Pigment Yellow 213. Such pigments are commercially available in powder or presscake form from numerous sources, including BASF Corporation, Engelhard Corporation, and Sun Chemical Corporation. Examples of usable black pigments include carbon pigments. The carbon pigment can be any commercially available carbon pigment that provides acceptable optical density and print properties. Suitable carbon pigments for use in the present system and method include, but are not limited to, carbon black, graphite, vitreous carbon, charcoal, and combinations thereof. Such carbon pigments can be produced by a variety of known processes, such as the channel process, contact process, furnace process, acetylene process, or thermal process, and are commercially available from such suppliers as Cabot Corporation, Columbian Chemicals Company, Evonik, and EI DuPont de Nemours and Company.Suitable carbon black pigments include MONARCH® 1400, MONARCH® 1300, MONARCH® 1100, MONARCH® 1000, MONARCH® 900, MONARCH® 880, MONARCH® 800, MONARCH® 700, CAB-O-JET® 200, CAB-O-JET® 300, CAB-O-JET® 450, REGAL®, BLACK Examples of pigments include, but are not limited to, Cabot pigments such as PEARLS®, ELFTEX®, MOGUL®, and VULCAN® pigments; Columbian pigments such as RAVEN® 5000 and RAVEN® 3500; and Evonik pigments such as color black FW200, FW2, FW2V, FW1, FW18, FW5160, FW5170, Special Black 6, Special Black 5, Special Black 4A, Special Black 4, PRINTEX® U, PRINTEX® 140U, PRINTEX® V, and PRINTEX® 140V. Other pigments include CAB-O-JET 352K, CAB-O-JET 250C, CAB-O-JET 260M, CAB-O-JET 270Y, CAB-O-JET 465M, CAB-O-JET 470Y, and CAB-O-JET 480V (available from Cabot Corporation).

[0052] The above list of pigments includes unmodified pigment particulates, small molecule attached pigment particulates, and polymer dispersed pigment particulates.

[0053] When forming an aqueous inkjet ink composition, the colorant may be provided as a colorant dispersion comprising a colorant and a solvent (e.g., water). The colorant may be in the form of particles and may have an average particle size of 20 nm to 500 nm, 20 nm to 400 nm, or 30 nm to 300 nm.

[0054] Various amounts of colorant can be used in the aqueous ink-jet ink composition. However, generally, the amount is selected so that the total solids content of the aqueous ink-jet ink composition (generally provided by the latex, water-soluble resin, and colorant) is 5% to 15%, 6% to 12%, or 7% to 10% by weight, where weight % is the total weight of solids / total weight of the aqueous ink-jet ink composition. * It points to 100.)

[0055] surfactants

[0056] Unlike the monodisperse latexes described above, the aqueous inkjet ink composition may contain one or more surfactants. Examples of suitable surfactants include anionic surfactants (such as sodium lauryl sulfate (SLS), Dextrol OC-40, Strodex PK 90, ammonium lauryl sulfate, potassium lauryl sulfate, sodium myreth sulfate, and dioctyl sodium sulfosuccinate series), nonionic surfactants (such as secondary alcohol ethoxylate series such as Surfynol® 104 series, Surfynol® 400 series, Dynol™ 604, Dynol™ 607, Dynol™ 810, EnviroGem® 360, Tergitol™ 15-s-7, Tergitol™ 15-s-9, TMN-6, TMN-100x, and Tergitol™ NP-9, Triton™ X-100), and cationic surfactants (such as Chemguard S-106A, Chemguard Examples of suitable surfactants include PolyFox™ TMPF-136A, 156A, 151N, Chemguard S-761p, S-764p, Silsurf® A008, Siltec® C-408, BYK 345, 346, 347, 348, and 349, and polyether siloxane copolymers TEGO® Wet-260, 270, and 500. Some amphoteric fluorinated surfactants, such as alkyl betaine fluorosurfactants or alkyl amine oxide fluorosurfactants, such as Chemguard S-500 and Chemguard S-111, can also be used.

[0057] Various amounts of surfactants can be used in the aqueous inkjet ink composition. In embodiments, the surfactant is present in an amount ranging from 0.01 wt % to 2 wt %, where wt % is the total weight of surfactants / total weight of the aqueous inkjet ink composition. *100.) When more than one type of surfactant is used, these amounts refer to the total amount of surfactant.

[0058] additives

[0059] Various additives can be used in aqueous ink-jet ink compositions to adjust their properties. Suitable additives include one or more of biocides, fungicides, stabilizers, pH adjusters such as acids or bases, phosphates, carboxylates, sulfites, amine salts, buffers, sequestering agents such as EDTA (ethylenediaminetetraacetic acid), antifoaming agents, and humectants.

[0060] Various amounts of additives may be used in the aqueous inkjet ink composition. In embodiments, additives are present in an amount ranging from 0.01% to 5% by weight, where weight % is the total weight of additives divided by the total weight of the aqueous inkjet ink composition. * 100.) When more than one type of additive is used, these amounts refer to the total amount of additives.

[0061] In at least embodiments, the aqueous inkjet ink composition is free of (i.e., does not contain) coagulants, free of (i.e., does not contain) flocculants, and free of (i.e., does not contain) plasticizers. In embodiments, the ink composition is free of (i.e., does not contain) any pyrrolidone-based solvents, such as N-methylpyrrolidone, and free of (i.e., does not contain) Texanol and Texanol isobutyrate.

[0062] Similarly, the aqueous inkjet ink composition of the present invention may have no (i.e., contain no) resins other than those provided by the monodisperse latex of the present invention. A single type of monodisperse latex may be used.

[0063] In embodiments, the aqueous inkjet ink composition comprises (or consists of) one or more of a solvent system, a monodisperse latex, a colorant, and optionally, a water-soluble resin and additives. In embodiments, the aqueous inkjet ink composition comprises (or consists of) a solvent system, a monodisperse latex, a colorant, a water-soluble resin, and optionally, additives. In any of these embodiments, the additives may be selected from stabilizers, surfactants, defoamers, humectants, and biocides. In any of these embodiments, the components may be selected from any of the solvent systems, monodisperse latexes, colorants, water-soluble resins, and additives disclosed herein. In any of these embodiments, the amounts of components may be used as described above. In any of these embodiments, a single type of monodisperse latex may be used. In any of the embodiments of this paragraph, the phrase "monodisperse latex" may also be substituted for "resin particles."

[0064] The aqueous inkjet ink composition can be formed by combining and mixing the desired components in the desired amounts. An exemplary method includes adding any of the disclosed monodisperse latexes (or resin particles) to a colorant dispersion to form a first mixture, and adding a second mixture containing a solvent system and additives to the first mixture to form the aqueous inkjet ink composition. Mixing and / or heating may be used during the method. The aqueous inkjet ink composition may be filtered before use. Exemplary details are provided in the examples below.

[0065] The aqueous inkjet ink composition may be used to form a printed image. In embodiments, such a method includes ejecting droplets of any of the disclosed aqueous inkjet ink compositions onto a substrate to form an image thereon. Such a method may further include incorporating the ink composition into an inkjet printing apparatus. The printing apparatus may use a thermal inkjet process, in which the ink composition in the nozzles is selectively heated in an imagewise pattern, thereby ejecting droplets of the ink composition in the imagewise pattern. Alternatively, the printing apparatus may use an acoustic inkjet process, in which droplets of the ink composition are ejected in the imagewise pattern by an acoustic beam. In yet another embodiment, the printing apparatus may use a piezoelectric inkjet process, in which droplets of the ink composition are ejected in the imagewise pattern by vibration of a piezoelectric vibrating element. Any suitable substrate may be used.

[0066] The method may include ejecting ink droplets in an imagewise pattern onto an intermediate transfer member, heating the image to partially or completely remove the solvent, and transferring the ink composition in the imagewise pattern from the intermediate transfer member to a final recording substrate. The intermediate transfer member may be heated to a temperature higher than that of the final recording sheet but lower than that of the ink composition in the printing apparatus. Offset or indirect printing processes are also disclosed, for example, in U.S. Pat. No. 5,389,958, the disclosure of which is incorporated herein by reference in its entirety.

[0067] Any suitable substrate or recording sheet can be used as the final recording sheet. Exemplary substrates include McCoy® Gloss #100 coated substrate, Xerox® Bold uncoated substrate, Kodak photo paper, Sterling® Ultra Web Matte (offset coated), TrueJet® Gloss Text (inkjet processed coating), and McCoy® Silk (offset coated). [Example]

[0068] The following examples are presented to further define the various classes of the present disclosure. These examples are intended for illustrative purposes only and are not intended to limit the scope of the present disclosure. Also, unless otherwise indicated, parts and percentages are by weight. As used herein, "room temperature" refers to a temperature of about 20°C to about 25°C. Example 1

[0069] A glass reactor was prepared by mixing 1.6 grams of reactive surfactant solution (Hitenol BC1025 from Montello), 36 grams of deionized water, and 0.4 g of NaHCO. The reaction was then purged with nitrogen for 30 minutes. The reactor was then continuously purged with nitrogen while stirring at 250 rpm. The reactor was then heated to 85°C and held there. Separately, 0.2 grams of ammonium persulfate initiator was dissolved in 5 grams of deionized water and added to the reactor.

[0070] Separately, a monomer emulsion was prepared in the following manner: 30 g of styrene, 5 g of butyl acrylate, 3 g of methacrylic acid, 1.5 g of polypropylene glycol methacrylate 370, 0.6 g of 1-dodecanethiol (DDT), 0.12 g of PEGDA 250, 0.8 g of Hitenol BC 1025, and 15 g of deionized water were mixed with intermittent mixing to form an emulsion. The emulsified mixture was slowly fed into a reactor for 3 hours, and the reaction was continued for 15 hours. The resulting latex was passed through a 25 μm filter and neutralized to pH 8.0 with 0.5 M KOH solution.

[0071] The dimensions of the resin particles were analyzed using a Malvern Nano-ZS. The size distribution of the resin particles in the resulting latex is shown in Figure 1. The peak at 101.0 nm has a width of 25.16 nm and contains 100% by volume of the resin particles. Other parameters were as follows: (v、10) = 71 nm, D (v、50 ) = 97 nm, and D (v、90) = 138 nm; D (z、ave) = 110 nm, and PDI = 0.004.

[0072] STEM images of the dried latex showed local crystallization, indicating the ability to form three-dimensional (3D) photonic crystals. Example 2

[0073] A glass reactor was prepared by mixing 1.6 grams of reactive surfactant solution (Hitenol BC1025 from Montello), 36 grams of deionized water, and 0.4 g of NaHCO. The reaction was then purged with nitrogen for 30 minutes. The reactor was then continuously purged with nitrogen while stirring at 250 rpm. The reactor was then heated to 85°C and held there. Separately, 0.2 grams of ammonium persulfate initiator was dissolved in 5 grams of deionized water and added to the reactor.

[0074] Separately, a monomer emulsion was prepared in the following manner: 31 g of styrene, 5 g of butyl acrylate, 3 g of methacrylic acid, 0.5 g of styrenesulfonic acid, 0.6 g of 1-dodecanethiol (DDT), 0.12 g of PEGDA 250, 0.6 g of Hitenol BC 1025, and 15 g of deionized water were mixed with intermittent mixing to form an emulsion. The emulsified mixture was slowly fed into a reactor for 3 hours, and the reaction was continued for 15 hours. The resulting latex was passed through a 25 μm filter and neutralized to pH 8.0 with 0.5 M KOH solution.

[0075] The dimensions of the resin particles were analyzed using a Malvern Nano-ZS. The size distribution of the resin particles in the resulting latex is shown in Figure 2. The peak at 86.74 nm has a width of 22.49 nm and contains 100% by volume of the resin particles. Other parameters were as follows: (v、10) = 61 nm, D (v、50) = 83 nm, and D (v、90) = 119 nm, D (z、ave) = 95 nm, and PDI = 0.023.

[0076] As shown in Figure 3, STEM images of the dried latex show localized crystallization, indicating the ability to form three-dimensional (3D) photonic crystals. Example 3

[0077] An aqueous inkjet ink composition was formed using the latex of Example 2. The following steps were used to form the aqueous inkjet ink composition shown in Table 1 below.

[0078] 1. The pigment dispersion was added to the deionized water and mixed for about 15 minutes using a pitch blade propeller at a speed of about 950 RPM.

[0079] 2. The latex from Example 2 was slowly added to the pigment dispersion and mixed for approximately 45 minutes (Mixture A).

[0080] 3. In a separate beaker, the water-soluble resin, co-solvent, humectant, stabilizer, surfactant, and wetting agent were mixed to form a homogenous mixture (Mixture B).

[0081] 4. Mixture B was slowly added to Mixture A. Once addition was complete, the mixer speed was set to about 650 RPM and the ingredients were allowed to mix for about an additional 75 minutes.

[0082] 5. Antifoam was added and mixing continued for approximately another 15 minutes.

[0083] 6. After mixing, the ink composition was allowed to stand at room temperature for approximately 60 minutes before checking the pH, conductivity, and surface tension.

[0084] 7. The ink composition was allowed to stand overnight and then filtered through a glass fiber filter (0.45 μm or 1 μm) (KST-47 filtration device available from Advantec MFS, Inc.).

[0085] [Table 1]

[0086] stability

[0087] The particle size and PDI of the ink compositions were measured using a Malvern Nano-Zetasizer before and after 3 days of air heat aging at 60°C. The results are shown in Table 2. (z、ave) The minimal change in viscosity (approximately 4%) and no change in PDI indicate that the ink composition is very stable. Additionally, the ink viscosity changed very little (less than 2%) after 3 days of air heat aging at 60°C.

[0088] [Table 2]

[0089] Printing performance

[0090] The ink compositions were jetted onto different paper substrates, including Kodak photographic paper, McCoy® gloss #100, and Xerox® Bold, using a Dimatix DMP2800 printer. The key test parameters used were: drop weight = 4.5-4.8 ng, drop velocity = 7 m / s, frequency = 5 kHz, voltage = 16-20 V, and print temperature = 20°C-40°C. Printing parameters were 600 x 600 dpi. Measurements were performed using a PIAS II device, a personal image analysis system with a digital magnifying glass. A high-resolution optical module with a field of view of approximately 3.2 mm x 2.4 mm and approximately 5 μm / pixel was used to measure dot size and diameter. The results are shown in Table 3. Additionally, the ink compositions exhibited excellent latency, passing through continuous jetting for >25 minutes.

[0091] [Table 3]

[0092] Shelf life

[0093] After jetting the ink composition, the ink composition was kept in the same print cartridge for 8 days at room temperature. After 8 days, the ink composition was jetted again. All nozzles began jetting without any signs of clogging. All nozzles jetted continuously for >15 minutes before the test was stopped. This experiment further demonstrates the long-term shelf life and colloidal stability of the ink composition. Example 4

[0094] A series of experiments were conducted to investigate the effect of water-soluble resins in latex-free versions of aqueous inkjet ink compositions. Table 4 below lists the samples that were prepared. Table 5 below lists the printing parameters tested and the results.

[0095] [Table 4]

[0096] [Table 5]

[0097] The results show that all water-soluble resins achieve acceptable viscosities, but printing performance is highly sensitive to the type and molecular weight of the water-soluble resin used, with the best performance being achieved with PEG 4000.

[0098] The word "exemplary" is used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects or designs. Further, for the purposes of this disclosure, unless otherwise specified, "a" or "an" means "one or more."

[0099] Unless already included, all numerical values ​​of parameters in this disclosure are preceded by the term "about," which means approximately. This encompasses the inherent variation in measuring the relevant parameter as understood by one of ordinary skill in the art. It also encompasses the exact value of the disclosed numerical value and any rounding of the disclosed numerical value.

[0100] The foregoing description of exemplary embodiments of the present disclosure has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise form disclosed, as modifications and variations are possible in light of the above teachings or may be acquired from practice of the present disclosure. The embodiments were chosen and described in order to explain the principles of the present disclosure and to enable those skilled in the art to utilize the disclosure in various embodiments, with various modifications suited to the particular uses contemplated. It is intended that the scope of the present disclosure be defined by the claims appended hereto and their equivalents. Preferred embodiments of the present invention are as follows. [1] An aqueous inkjet ink composition comprising water, resin particles, and a colorant, wherein the resin particles comprise a polymerization product of reactants including a monomer, an acidic monomer, a polyfunctional monomer, and a reactive surfactant, and the resin particles have a D of about 150 nm or less. (z、ave) , D less than about 200 nm (v、90) and a polydispersity index (PDI) of about 0.050 or less. [2] The polymerization product has pK a The aqueous inkjet ink composition according to [1], comprising two different acidic monomers having a value, the polyfunctional monomer, and the reactive surfactant. [3] The two different acidic monomers have a higher pK in the range of about 0.1 to about 10. a Acidic monomers with lower pK a The aqueous inkjet ink composition according to [2] above, wherein the acidic monomer having the formula: [4] The aqueous inkjet ink composition according to [2] above, wherein the two different acidic monomers are a methacrylic acid monomer and a sulfonic acid monomer. [5] The aqueous inkjet ink composition according to [4] above, wherein the sulfonic acid monomer is styrene sulfonic acid. [6] The aqueous inkjet ink composition according to [1], wherein the reactants include styrene, alkyl acrylate, methacrylic acid, sulfonic acid monomer, poly(ethylene glycol) diacrylate, and anionic ether sulfate reactive surfactant. [7] The aqueous inkjet ink composition according to [6], wherein the sulfonic acid monomer is styrene sulfonic acid. [8] The resin particles have a D of about 120 nm or less. (z、ave) , D less than about 150 nm (v、90) and a PDI of about 0.025 or less. [9] The aqueous inkjet ink composition according to [1], wherein the resin particles crystallize to form 3D photonic crystals when a latex containing the resin particles is dried.

[10] The aqueous inkjet ink composition according to [1] above, further comprising a water-soluble resin.

[11] The aqueous inkjet ink composition according to

[10] , wherein the water-soluble resin is polyethylene glycol having a molecular weight of about 4000 g / mol.

[12] The aqueous inkjet ink composition according to [1], further comprising a water-soluble resin, wherein the reactants comprise styrene, alkyl acrylate, methacrylic acid, sulfonic acid monomer, poly(ethylene glycol) diacrylate, and an anionic ether sulfate reactive surfactant.

[13] The aqueous inkjet ink composition according to

[12] , wherein the water-soluble resin is polyethylene glycol having a molecular weight of about 4000 g / mol, and the sulfonic acid monomer is styrene sulfonic acid.

[14] A method for forming the aqueous inkjet ink composition according to [1] above, the method comprising adding a latex containing the resin particles to a colorant dispersion containing the colorant to form the aqueous inkjet ink composition.

[15] A method for using the aqueous inkjet ink composition described in [1] above, comprising ejecting droplets of the aqueous inkjet ink composition described in [1] above onto a substrate to form an image thereon.

Claims

1. 1. An aqueous inkjet ink composition comprising water, resin particles, and a colorant, wherein the resin particles comprise a polymerization product of reactants including styrene, an alkyl acrylate, methacrylic acid, a sulfonic acid monomer, poly(ethylene glycol) diacrylate, and an anionic ether sulfate reactive surfactant, and wherein the resin particles have a D of 150 nm or less. (z、ave) , D less than 200 nm (v、90) and a polydispersity index (PDI) of 0.050 or less.

2. An aqueous inkjet ink composition as described in claim 1, wherein the methacrylic acid and the sulfonic acid monomer are present in a weight ratio ranging from 0.1 to 10.

3. The aqueous inkjet ink composition of claim 1 , wherein the sulfonic acid monomer is styrene sulfonic acid.

4. The aqueous inkjet ink composition of claim 1, wherein the alkyl acrylate is butyl acrylate.

5. The resin particles have a D of 120 nm or less (z、ave) , D less than 150 nm (v、90) and a PDI of 0.025 or less.

6. The aqueous inkjet ink composition of claim 1 , wherein when the latex containing the resin particles is dried, the resin particles crystallize to form 3D photonic crystals.

7. The aqueous ink-jet ink composition of claim 1 , further comprising a water-soluble resin.

8. 8. The aqueous ink-jet ink composition of claim 7, wherein the water-soluble resin is polyethylene glycol having a molecular weight of 4000 g / mol.

9. The aqueous inkjet ink composition of claim 8, wherein the sulfonic acid monomer is styrene sulfonic acid.

10. The aqueous inkjet ink composition of claim 8, wherein the alkyl acrylate is butyl acrylate.

11. 2. A method of forming the aqueous inkjet ink composition of claim 1, comprising adding a latex containing the resin particles to a colorant dispersion containing the colorant to form the aqueous inkjet ink composition.

12. 10. A method of using the aqueous ink-jet ink composition of claim 1, comprising ejecting droplets of the aqueous ink-jet ink composition of claim 1 onto a substrate to form an image thereon.

Images