INK COMPOSITIONS WITH pH-RESPONSIVE RESIN PARTICLES

Abstract

To provide ink compositions that prevent inhibition of electrostatic stability due to flocculation and aggregation of resin particles, and prevent reduction in the water-fastness of images printed.SOLUTION: Ink compositions are provided which may comprise water, resin particles, a colorant, and optionally a wax, the resin particles comprising a polymerization product of reactants comprising a dioxane / dioxolane monomer and an additional monomer, where the dioxane / dioxolane monomer is an ester of (meth)acrylic acid with an alcohol comprising a dioxane moiety, an ester of (meth)acrylic acid with an alcohol comprising a dioxolane moiety, or both.SELECTED DRAWING: None

Description

[Background technology]

[0001] The latex of an aqueous inkjet ink composition is often synthesized by emulsion or microemulsion polymerization of hydrophobic monomers in water. The latex is added to the aqueous inkjet ink composition along with water, a water-dispersible colorant, and a hydrophilic solvent. The resin particles of the latex act as a binder that helps form a water-permeable polymer film that protects the printed image. To adjust the viscosity of the aqueous inkjet ink composition, a water-soluble resin is often added to the ink composition. However, the water-soluble resin can induce aggregation and agglomeration of the resin particles and inhibit their electrostatic stability. The water-soluble resin also reduces the waterfastness of images printed from the aqueous inkjet ink composition. Summary of the Invention

[0002] The present disclosure provides latexes that can be used to provide resin particles for various compositions, such as ink compositions and adhesives. The resin particles are polymerized from dioxane / dioxolane monomers. Embodiments of the present resin particles exhibit pH-responsive properties that can be utilized to provide improved latexes and related compositions. For example, embodiments of the resin particles have a pH-dependent size, including exhibiting larger sizes at higher pH values. The viscosity of latexes containing such resin particles is also pH-dependent, including exhibiting higher viscosities at higher pH values. This feature enables resin particles to be synthesized at low pH values ​​and low viscosities. Ink compositions can then be made with a desired viscosity at higher pH values ​​using relatively small amounts of resin particles. Furthermore, water-soluble resin or silica additives are not required for viscosity adjustment, although they can be used. In light of this unique pH-responsiveness, embodiments of the resin particles, latexes, and related compositions may be referred to as "pH-responsive" in this disclosure. Ink compositions containing embodiments of the resin particles also exhibit extended open-air stability, facilitating the collection of waste ink from the open-air waste tray of aqueous inkjet systems. Finally, embodiments of the resin particles also have a relatively high glass transition temperature (T g ) for stability, scratch resistance, reduced adhesion, and offset transfer. g While high T values ​​are desirable, this property is also known to adversely affect gloss differential and adhesion. g Ink compositions containing embodiments of the resin particles exhibit low differential gloss values ​​and high adhesion, including excellent water resistance.

[0003] In embodiments, an ink composition is provided that includes water, resin particles, a colorant, and optionally a wax, wherein the resin particles include the polymerization product of a reactant including a dioxane / dioxalane monomer and an additional monomer, and the dioxane / dioxalane monomer is an ester of (meth)acrylic acid and an alcohol comprising a dioxane moiety, an ester of (meth)acrylic acid and an alcohol comprising a dioxalane moiety, or both.

[0004] 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. DETAILED DESCRIPTION OF THE INVENTION

[0005] latex

[0006] In one aspect, a latex is provided. Such a latex includes resin particles synthesized from various monomers to form a polymeric material from which the resin particles are composed. At least one type of monomer is used that is an ester of (meth)acrylic acid with an alcohol containing a dioxane moiety or an alcohol containing a dioxolane moiety. (The use of "(meth)", for example, in "(meth)acrylic acid" refers to both acrylic acid and methacrylic acid.) In this disclosure, this type of monomer may be referred to as a "dioxane / dioxolane monomer." The phrase dioxane / dioxolane monomer encompasses both a monomer that is an ester of (meth)acrylic acid with an alcohol containing a dioxane moiety, a monomer that is an ester of (meth)acrylic acid with an alcohol containing a dioxolane moiety, and both such monomers. The dioxane moiety may be a 1,3-dioxane moiety, and the dioxolane moiety may be a 1,3-dioxolane moiety. The alcohol containing the dioxane / dioxolane moiety can be an acetal of a triol, a ketal of a triol, or a carbonate of a triol. Exemplary triols include glycerol and trimethylolpropane. The triol can be unsubstituted or substituted. "Substituted" means that one or more bonds to a carbon or hydrogen are replaced by bonds to non-hydrogen and non-carbon atoms. The dioxane / dioxolane monomer can have Formula I (dioxane) or II (dioxolane) as shown below, where R is selected from hydrogen and methyl, R' is selected from hydrogen and ethyl, and Z is selected from hydrogen, the oxygen of a carbonyl group, an alkyl group, an aryl group, and an alkoxy group. Either or both types of monomers can be used in the resin particles. [ka]

[0007] A carbonyl group refers to a C=O group, i.e., Z is O covalently bonded to a carbon through a double bond, thereby forming a carbonyl group between two oxygen atoms in a 5- or 6-membered ring. An alkyl group can be linear or branched. An alkyl group can have 1 to 20 carbons. This includes 1 to 18 carbons and 1 to 10 carbons, e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 carbons. An alkyl group can be substituted or unsubstituted. An aryl group can be monocyclic having one aromatic ring, e.g., benzene, or polycyclic having one or more fused rings. An aryl group can be unsubstituted or substituted as described above for alkyl groups, but substituted aryl groups also include aryl groups in which a bond to a hydrogen atom is replaced by a bond to an unsubstituted or substituted alkyl group as described above. An alkoxy group refers to an -O-alkyl group.

[0008] Exemplary dioxane / dioxolane monomers include glycerol formal (meth)acrylate, trimethylolpropane formal (meth)acrylate, and isopropylidene glycerol (meth)acrylate. A single type or a combination of different types of dioxane / dioxolane monomers may be used. However, in embodiments, the dioxane / dioxolane monomer is glycerol formal (meth)acrylate. Glycerol formal (meth)acrylate has a relatively high T- g (about 85-90°C). In this disclosure, the name "glycerol formal (meth)acrylate" (as well as the names of the other dioxane / dioxolane monomers described in this paragraph) refers to either the dioxane isomer, the dioxolane isomer, or both; that is, all possibilities are encompassed by the name.

[0009] At least embodiments of the dioxane / dioxolane monomers are amphiphilic, in contrast to hydrophilic monomers, which have a high affinity for polar solvents such as water, but limited affinity for non-polar solvents such as hydrocarbons, ethers, and esters.

[0010] Generally, additional monomers are used to form resin particles. Various types of monomers can be used, such as 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; acrylate, β-CEA), phenyl acrylate, methyl alpha chloroacrylate; butadiene; isoprene; methacrylonitrile; acrylonitrile; vinyl ethers such as vinyl methyl 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. Combinations of different types of these monomers may be used. In embodiments, the monomers used to form the resin particles include styrene, alkyl (meth)acrylates (e.g., methyl (meth)acrylate, ethyl (meth)acrylate), butyl (meth)acrylate, or combinations thereof. Thus, the alkyl group of the alkyl (meth)acrylate can have 1 or more carbons, 2 or more carbons, 4 or more carbons, or 1 to 6 carbons.

[0011] Acidic monomers may be used to form the resin particles, such as (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, styrene sulfonic acid, vinyl sulfonate, 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-vinylsuccinic acid, and the like. Examples of suitable acidic monomers include amido acid, mesaconic acid, methacryloylalanine, acryloylhydroxyglycine, sulfoethyl methacrylic acid, sulfopropyl acrylic acid, styrene sulfonic acid, sulfoethyl acrylic acid, 2-methacryloyloxymethane-1-sulfonic acid, 3-methacryloyloxypropane-1-sulfonic acid, 3-(vinyloxy)propane-1-sulfonic acid, ethylene sulfonic acid, vinyl sulfuric acid, 4-vinylphenyl sulfuric acid, ethylene phosphonic acid, vinyl phosphoric acid, vinyl benzoic acid, 2-acrylamido-2-methyl-1-propanesulfonic acid, and combinations thereof. These acidic monomers also include salts thereof, such as salts of sulfonic acid.

[0012] In embodiments, the two different acidic monomers each have a different pK a The pK of two different acidic monomers is used to form resin particles with a The values ​​may differ from each other 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 have the higher pK in the range of 0.1 to 10. a Acidic monomers with lower pK ais present in the monomer emulsion used to form the resin particles in a weight ratio with an acidic monomer having, including ranges of 0.5 to 8 and 1 to 6. In embodiments, two different types of acidic monomers are used to form the resin particles, including methacrylic acid and sulfonic acid.

[0013] Multifunctional monomers can be used to form 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 250 g / mol. Other poly(ethylene glycol) di(meth)acrylates can be used, including those with molecular weights ranging from 214 g / mol to 1000 g / mol, 214 g / mol to 500 g / mol, and 214 g / mol to 300 g / mol. These molecular weight values ​​can be determined using gel permeation chromatography. Other 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; and 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 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 compounds obtained by substituting methacrylate for the acrylate of these compounds.

[0014] Reactive surfactants can be used to form resin particles. Suitable reactive surfactants contain polymerizable (and therefore reactive) groups so that they can be incorporated into resin particles. Exemplary reactive surfactants include anionic ether sulfate reactive surfactants, such as those in the commercially available Hitenol series, such as Hitenol AR10-25. Other suitable reactive surfactants include polyoxyethylene alkyl phenyl ether ammonium sulfates, including Hitenol BC-10, BC-20, BC10-25, BC-2020, BC-30; polyoxyethylene styrenated phenyl ether ammonium sulfates, including Hitenol AR-10, AR-20, 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.

[0015] A chain transfer agent can be used to form the resin particles. 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.

[0016] In embodiments, certain monomers may be excluded when forming the resin particles, including one or more of the following: vinyl-imidazolium monomers, urethane (meth)acrylate monomers, and silyl ester monomers, such as (meth)acrylic acid triisopropylsilyl ester.

[0017] When forming a latex containing resin particles, various combinations of the monomers described above can be used in a monomer emulsion containing a solvent. Water is commonly 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, including achieving the property values ​​described below. Exemplary amounts are provided below.

[0018] The dioxane / dioxolane monomers may be used in the monomer emulsion in amounts ranging from 1% to 40%, 1% to 30%, 1% to 20%, 2% to 18%, and 5% to 15% by weight, where weight % is the total weight of the dioxane / dioxolane monomers divided by the total weight of the monomers in the monomer emulsion excluding reactive surfactants. *(The weight percent refers to 100.) Acidic monomers can be used in the monomer emulsion in amounts ranging from 2% to 20% by weight and from 5% to 15% by weight. (The weight percents have similar meanings as those described for dioxane / dioxolane monomers.) As noted above, different pK a Two different types of acidic monomers having different acidic acid values ​​may be used in the weight ratios described above. Multifunctional monomers, including difunctional monomers, may be used in the monomer emulsion in amounts ranging from 0.001% to 1% by weight, 0.001% to 0.8% by weight, and 0.01% to 0.6% by weight. (The weight percentages have a similar meaning to those described for the dioxane / dioxolane monomers.) Other monomers (e.g., styrene, alkyl (meth)acrylates) may be present in amounts ranging from 70% to 97% by weight and 75% to 90% by weight. (The weight percentages have a similar meaning to those described for the dioxane / dioxolane monomers.) When present, alkyl (meth)acrylates (e.g., methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate) may be present in amounts ranging from at least 15% by weight, at least 20% by weight, or 15% to 30% by weight.

[0019] 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. * (Refers to 100). This range includes 1.5% to 5% by weight.

[0020] 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.)

[0021] In embodiments, the monomer emulsion comprises (or consists of) a solvent, a dioxane / dioxolane monomer, and an additional monomer. In embodiments, the additional monomer is an acidic monomer (e.g., methacrylic acid, sulfonic acid, or both). In embodiments, at least two additional monomers, a relatively high T g monomers (e.g., styrene or methyl methacrylate) and relatively low T g In some embodiments, the monomer emulsion comprises a solvent, a dioxane / dioxolane monomer, styrene, an alkyl acrylate (e.g., butyl acrylate), an acidic monomer (methacrylic acid, sulfonic acid, or both), a multifunctional monomer (e.g., a difunctional monomer such as poly(ethylene glycol) diacrylate), and a reactive surfactant (e.g., an anionic ether sulfate). In any of these embodiments, a chain transfer agent may be used. In any of these embodiments, various amounts of monomer, reactive surfactant, and chain transfer agent may be used, as described above. The remainder may consist of solvent.

[0022] In embodiments, the monomer emulsion does not have (i.e., does not contain) a surfactant. However, in other embodiments, a surfactant may be used. Here, "surfactant" refers to non-reactive, non-polymerizable anionic surfactants such as sodium dodecyl sulfate (SDS), sodium dodecylbenzenesulfonate, sodium dodecylnaphthalene sulfate; dialkylbenzene alkyl sulfate; palmitic acid; alkyldiphenyloxide disulfonate; 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-polymeric 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.

[0023] In embodiments, the monomer emulsion does not have (i.e., does not include) silica particles. Although silica particles have been used to increase viscosity, embodiments of the present resin particles can provide a high viscosity latex without including such silica particles. Commercially available silica particles that may be excluded are the following: various grades of LUDOX colloidal silica, such as FM, SM, HS-30, HS-40, LS, TM-40, TM-50, SM-AS, AS-30, AS-40, AM, HSA, TMA, PX-30, Pt-40, PW-50, CL, and CL-P, and various grades of Nissan Chemical silica, such as SNOWTEX ST-20L, ST-30, ST-40, ST-50, ST-OS, ST-O, ST-O-40, ST-OL, ST-C, ST-C-30, ST-CM, ST-N, STN30G, ST-N40, ST-NS, ST-XS, ST-S, ST-UP, ST-O-UP, MA-ST-UP, ST-PS-S, AMT-330S, HX-305M1, and HX-305M5.

[0024] Various polymerization techniques can be used to form resin particles, such as monomer-starved emulsion polymerization, conventional emulsion polymerization, suspension polymerization, miniemulsion polymerization, nanoemulsion polymerization, seeded emulsion polymerization, and microemulsion polymerization. These polymerization techniques can use any of the monomer emulsions described above. An exemplary monomer-starved emulsion polymerization process is described below. However, as noted above, other processes can be used. (See also Example 4, which describes an exemplary seeded emulsion polymerization process.)

[0025] An exemplary method for making a latex containing resin particles 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 reactive surfactants described above can be used. The reactive surfactant in the reactive surfactant solution can be the same type or a different type compared to the reactive surfactant that may be present in the monomer emulsion. The reactive surfactant solution can further include a buffer. Various buffers can be used, such as sodium bicarbonate, sodium carbonate, and ammonium hydroxide. The reactive surfactant can be used in an amount ranging from 1% to 10% by weight and from 2% to 5% by weight. (Where wt % is the total weight of reactive surfactants) / (total weight of reactive surfactant solution). * 100.) The buffer may be used in an amount ranging from 0.25% to 2.5% by weight. (% by weight has the same meaning as described above.)

[0026] An initiator can be included in the reactive surfactant solution. Alternatively, a separate initiator solution containing an initiator and any of the solvents described above can be formed, and the separate initiator solution is added to the reactive surfactant solution. The separate initiator solution can be added before adding the monomer emulsion. An additional amount of the separate initiator solution can be added after adding the monomer emulsion. Examples of suitable initiators include water-soluble initiators such as ammonium persulfate (APS), sodium persulfate, and potassium persulfate, as well as organic peroxides and organic-soluble initiators including azo compounds, such as Vazo peroxides (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 0.05% to 2.5% by weight, where % by weight is the total weight of the initiator divided by the total weight of the reactive surfactant solution. * It points to 100.)

[0027] 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 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 of the silica particles described above. As a result, the resin particles may be characterized as not having (i.e., does not contain) any of the surfactants described above and / or any of the silica particles. 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.

[0028] 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.

[0029] 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 resin particles of a high viscosity latex. 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 addition of the monomer emulsion, the polymerization can be continued for an additional period of time, with or without the addition of additional initiator. Exemplary additional durations include those in the range of 1 hour to 18 hours. Both the addition of the monomer emulsion and the subsequent polymerization can be carried out under an 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. Treated or untreated latex can be used to form the ink compositions described below.

[0030] The monomer-starved emulsion polymerization process described above does not involve the use of resin seeds in forming the resin particles. However, as noted above, seeded emulsion polymerization techniques can be used (see Example 4).

[0031] 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.

[0032] 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, as described above. Therefore, a variety of compositions are encompassed, including those based on various polymerization products of reactants containing various combinations of monomers. As noted above, the reactants include dioxane / dioxolane monomers, but the selection of other monomers is not otherwise particularly limited. For clarity, the composition of the resin particles can be identified by reference to the monomers being polymerized, recognizing that the chemical form of these monomers generally changes as a result of the polymerization reaction. In embodiments, the resin particles comprise (or consist of) the polymerization product (e.g., copolymer) of reactants containing dioxane / dioxolane monomers and additional monomers. In embodiments, the resin particles comprise (or consist of) the polymerization product (e.g., copolymer) of reactants containing dioxane / dioxolane monomers, additional monomers, and polyfunctional monomers. In embodiments, the resin particles comprise (or consist of) the polymerization product (e.g., copolymer) of reactants including dioxane / dioxolane monomer, styrene, an alkyl acrylate (e.g., butyl acrylate), an acidic monomer (methacrylic acid, sulfonic acid, or both), a polyfunctional monomer (e.g., a difunctional monomer such as poly(ethylene glycol) diacrylate), and a reactive surfactant (e.g., an anionic ether sulfate). In each of these embodiments, an initiator (or a portion thereof) 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. (Experiments have shown that monomer conversion exceeds 99.9%). For example, the amount of dioxane / dioxolane monomer in the resin particles may range from 1% to 40% by weight. As stated above, this weight percent is calculated by dividing the total weight of dioxane / dioxolane monomers by the total weight of monomers in the resin particles, excluding reactive surfactants. * It points to 100.

[0033] Using a specific exemplary composition, the composition of the resin particles can also be identified as crosslinked poly[(styrene)-ran-(butyl acrylate)-ran-(methacrylic acid)-ran-(glycerol formal (meth)acrylate)-ran-(styrene sulfonic acid)-ran-(anionic ether sulfate)]. In this description, the different chemical moieties resulting from the polymerization reaction are identified by reference to the corresponding monomer in parentheses, with "ran" referring to the random incorporation of different monomers into the copolymer. Use of this description encompasses the presence of an initiator (or a portion thereof) at the beginning of each copolymer, as well as crosslinking via polyfunctional / difunctional monomers.

[0034] In embodiments in which certain monomers are excluded from forming the resin particles, it follows that such monomers do not participate in the polymerization reaction and form the polymer matrix of the resin particles. Thus, in these embodiments, the composition of the resin particles may be described as being free of (i.e., free of) one or more of vinyl-imidazolium monomers, urethane (meth)acrylate monomers, and silyl ester monomers, such as (meth)acrylic acid triisopropylsilyl ester.

[0035] In embodiments, the latex may be described as having no (i.e., no) resins / polymers other than those provided by the resin of the resin particles themselves, including having no polyurethanes, polyurethane (meth)acrylates, poly(meth)acrylates (other than the resin particles themselves), polyesters, silyl ester copolymers, silyl (meth)acrylate polymers, or combinations thereof.

[0036] Since the resin / polymer that makes up the resin particles has already been polymerized, the latex itself is generally not curable and therefore does not have (i.e., does not contain) an initiator. This does not exclude the presence of small amounts of unreacted or reacted initiator that may be incorporated into the polymer chain. Similarly, the latex may be described as being free (i.e., does not contain monomers).

[0037] In embodiments, the latex may also be described as being free of (i.e., free of) fungicides / biocides such as medetomidine.

[0038] The water content of the latex can be at least 40% by weight, including at least 50% by weight and at least 60% by weight, where these weight percentages refer to the weight of water compared to the total weight of the latex.

[0039] In embodiments, the resin particles have a core / shell morphology. Core / shell resin particles can be formed using seed emulsion polymerization, in which one monomer emulsion (seed monomer emulsion) is used to form the core and a different monomer emulsion (feed monomer emulsion) is used to form the "shell" (see Example 4). However, seed emulsion polymerization can be used to form resin particles in which the seed monomer emulsion and the feed monomer emulsion have the same composition.

[0040] The resin particles may be characterized by their size. The size of the particles is determined by the D 50 It can be reported as particle size, which means the diameter at which 50% (by volume) of the sample consists of particles with a diameter less than that diameter value. 50 Particle size may be measured using a Malvern Zetasizer Nano ZS. Validation of light scattering techniques and methods may be performed using NIST polystyrene nanosphere control samples with diameters in the range of 20 nm to 200 nm, available from Microspheres-Nanospheres (a Corpuscular company of Microtrac) or third-party vendors (such as ThermoFisher Scientific). At least embodiments of the resin particles have a pH-dependent size, and thus size may be reported for a specific pH. In embodiments, resin particles have a D at a pH of 3. 50 Particle size greater than D at pH 8 50The particle size may be characterized as being at least 15% larger, at least 18% larger, at least 20% larger, at least 22% larger, at least 25% larger, or 15% to 30% larger. In embodiments, the D 50 The particle size is 100 nm or less, 90 nm or less, 80 nm or less, 70 nm or less, or in the range of 60 nm to 90 nm.

[0041] Latices containing the present resin particles can be characterized by their viscosity. Viscosity values ​​can refer to a specific temperature and a specific solids content and can be measured using a tuning fork vibration viscometer (Cole-Parmer) as described in the Examples below. Again, because at least embodiments of the resin particles cause the latex to have a pH-dependent viscosity, viscosity can be reported relative to a specific pH. In embodiments, latexes containing resin particles are characterized by a viscosity at room temperature, 30% solids, and pH 8 that is greater than the viscosity at room temperature, 30% solids, and pH 3. This includes 2 times greater, 3 times greater, 4 times greater, 5 times greater, or 2 to 10 times greater. In embodiments, the viscosity at room temperature, 30% solids, and pH 3 is in the range of 10 cP to 100 cP. This includes 10 cP to 80 cP, 10 cP to 40 cP, and 15 cP to 40 cP. All of these viscosities are initial viscosities measured within one day of latex formation.

[0042] The resin particles also have their T g The value of T g The T value can be measured using Differential Scanning Calorimetry (DSC) TA Instruments Discovery DSC 2500 as described in the Examples below. In some embodiments, T g is in the range of about 50°C to about 100°C, which includes the ranges of 50°C to 90°C and 50°C to 80°C.

[0043] Ink composition

[0044] Any of the resin particles / latexes described above can be used to provide an ink composition. The type of ink composition is not particularly limited. However, ink compositions containing a significant amount of water, for example, at least 50% by weight, are particularly useful. Exemplary ink compositions include aqueous inkjet ink compositions and pen ink compositions. Exemplary aqueous inkjet ink compositions are described below. However, it is understood that the present disclosure also extends to other types of ink compositions.

[0045] The resin particles may be present in the aqueous inkjet ink composition in an amount ranging from 1% to 10% by weight and from 5% to 10% by weight, where % by weight is the total weight of the resin particles 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.

[0046] Solvent System

[0047] 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.

[0048] 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, diethylene glycol, 1,2,4-butanetriol, glycerol, diglycerol, and triethylene glycol.

[0049] In embodiments, the solvent system comprises water, a 1,2-alcohol (eg, 1,2-hexanediol), a glycol (eg, propylene glycol), and glycerol.

[0050] 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.

[0051] 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.)

[0052] coloring agent

[0053] 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 Food Black No. 1, Food Black No. 2, Food Red No. 40, Food Blue No. 1, and Food Yellow No. 7, FD&C dyes, acid black dyes (Nos. 1, 7, 9, 24, 26, 48, 52, 58, 60, 61, 63, 92, 107, 109, 118, 119, 131, 140, 155, 156, 172, and 194), and acid red dyes (Nos. 1, 8, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 60, 61, 63, 92, 107, 109, 118, 119, 131, 140, 155, 156, 172, and 194), and acid red dyes (Nos. 1, 8, 32, 33, 34, 35, 36, 37, 38, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 60, 61, 63, 92, 107, 35, 37, 52, 57, 92, 115, 119, 154, 249, 254, 256), Acid Blue Dye (No. 1, 7, 9, 25, 40, 45, 62, 78, 80, 92, 102, 104, 113, 117, 127, 158, 175, 183, 193, 209), Acid Yellow Dye (No. 3, 7, 17, 19, 23, 25, 29, 38, 42, 49, 59, 61, 72, 73, 114, 128, 151), Direct Black Dye (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, 1 00, 106, 107, 118, 127, 132, 142, 157), reactive dyes such as reactive red dye (No. 4, 31, 56, 180), reactive black dye (No. 31), and reactive yellow dye (No. 37), anthraquinone dyes, monoazo dyes, disazo dyes, phthalocyanine derivatives including various phthalocyanine sulfonates, aza(18)annulenes, formazan copper complexes, and triphenodioxazines.

[0054] 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), iron oxide, and titanium dioxide (TiO2), 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, glassy 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).

[0055] The above list of pigments includes unmodified pigment particulates, small molecule attached pigment particulates, self-dispersed pigment particulates, and polymer-dispersed pigment particulates.

[0056] 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.

[0057] Various amounts of colorant can be used in the aqueous ink-jet ink composition. However, the amount is generally selected so that the total solids content of the aqueous ink-jet ink composition (generally provided by the resin particles, colorant, and wax, if present) is 5% to 15%, 6% to 12%, or 7% to 10% by weight (where % by weight is the total weight of solids / total weight of the aqueous ink-jet ink composition). * It points to 100.)

[0058] wax

[0059] The aqueous inkjet ink composition may contain a wax. Exemplary waxes include paraffin wax, polyethylene wax, polypropylene wax, microcrystalline wax, polyolefin wax, montan ester wax, and carnauba wax. Waxes having a melting point in the range of 50°C to 150°C may be used. Nanoscale (e.g., diameters of 1000 nm or less, 500 nm or less, or 100 nm or less) wax emulsions based on carnauba wax and paraffin wax may be used. Michelman waxes can be used (e.g., Michem Lube 103DI, 124, 124P135, 156, 180, 182, 190, 270R, 368, 511, 693, 723, 743, 743P, and 985, and Michem Emulsion 24414, 34935, 36840, 41740, 43040, 43240, 44730, 47950, 48040M2, 61355, 62330, 66035, 67235, 70750, 71150, 71152, 91735, 93235, 93335, 93935, and 94340). Waxes from Byk may also be used, including Aquacer 2500, Aquacer 507, Aquacer 513, Aquacer 530, Aquacer 531, Aquacer 532, Aquacer 535, Aquacer 537, Aquacer 539, and Aquacer 593. In embodiments, the wax is an anionic nanoscale wax emulsion, such as Michem Lube 190.

[0060] Various amounts of wax 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 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.)

[0061] surfactants

[0062] The aqueous inkjet ink composition may include 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 Surfynol® 104 series, Surfynol® 400 series, Dynol™ 604, Dynol™ 607, Dynol™ 810, EnviroGem® 360, secondary alcohol ethoxylate series such as 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. Other surfactants that can be used include Surfynol PSA 336, Surfynol SE-F, and Surfynol 107L.

[0063] 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 two or more surfactants are used, these amounts refer to the total amount of surfactants.

[0064] additives

[0065] Various additives can be used in aqueous ink-jet ink compositions to adjust their properties. Suitable additives include biocides, fungicides, stabilizers, pH adjusters such as acids or bases, phosphates, carboxylates, sulfites, amine salts, buffers, and the like, sequestering agents such as EDTA (ethylenediamine tetraacetic acid), antifoaming agents, defoamers, and wetting agents.

[0066] 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 additive is used, these amounts refer to the total amount of additives.

[0067] 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 aqueous inkjet 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. In embodiments, the aqueous inkjet ink composition is free of (i.e., does not contain) silica particles.

[0068] As described above, aqueous inkjet ink compositions based on the present resin particles do not require the addition of additives to further adjust viscosity. This means that the aqueous inkjet ink composition may not have (i.e., does not contain) a water-soluble resin or emulsion, an aqueous binder, a polymeric dispersant, or a combination thereof. This includes the possible exclusion of any of the water-soluble resin or emulsion, aqueous binder, and polymeric dispersant described below. However, it is understood that such compounds may be included in some embodiments. Finally, it should be noted that the terms water-soluble resin, water-soluble emulsion, aqueous binder, and polymeric dispersant do not encompass the present resin particles themselves. Exemplary water-soluble resins / emulsions are polyethylene glycol and polyvinylpyrrolidone.

[0069] Exemplary aqueous binders are 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, and PVP K-85 available from ISP; and Ganex P-904LC and PVP / VA W-63. Other exemplary aqueous binders that may be removed include those available from Johnson Polymers (BASF), such as Joncryl 537, Joncryl H538, and Joncryl H538.

[0070] Exemplary polymeric dispersants include acrylic polymers such as styrene-acrylic copolymers and vinylpyrrolidone copolymers, urethane or polyurethane dispersions, and acrylic-urethane hybrid dispersions. More specific polymeric dispersants that may be excluded include those available from Johnson Polymers (BASF), such as Joncryl® 671, Joncryl® 683, Joncryl® 296, Joncryl® 690, Joncryl HPD 296, Joncryl HPD96-E, Joncryl LMV 7085, and Joncryl 8082. Other dispersants that may be excluded include those described in EP Patent No. 2097265, which is incorporated by reference for purposes of dispersants, and those described in U.S. Patent Application No. 2019284414, which is incorporated by reference for purposes of dispersants.

[0071] Similarly, the aqueous inkjet ink composition may have no (i.e., does not contain) any resin other than that provided by the resin of the resin particles. This includes having no polyurethane, poly(meth)acrylate (other than the resin particles themselves), polyester, or a combination thereof. A single type of resin may be used. Similarly, the aqueous inkjet ink composition itself is generally not curable and therefore has no (i.e., does not contain) an initiator. Note that any other exclusions referenced above regarding resin particles and latex may apply to embodiments of the aqueous inkjet ink composition.

[0072] In embodiments, the ink composition (e.g., an aqueous inkjet ink composition) comprises (or consists of) a solvent system, resin particles, a colorant, and optionally one or more of a wax and additives. In embodiments, the ink composition comprises (or consists of) a solvent system, resin particles, a colorant, a wax, and optionally additives. In any of these embodiments, the additives may be selected from stabilizers, surfactants, antifoaming agents, defoamers, humectants, and biocides. In any of these embodiments, the components may be selected from any of the solvent systems, resin particles, colorants, waxes, and additives disclosed herein. In any of these embodiments, the amounts of components may be used as described above.

[0073] An ink composition (e.g., an 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 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. A third mixture containing a wax may be added to the combined first and second mixtures. 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.

[0074] characteristics

[0075] Aqueous inkjet ink compositions may be characterized by their differential gloss. Differential gloss may be measured as described in the Examples below. In embodiments, aqueous inkjet ink compositions exhibit a differential gloss of less than 5 units, less than 4 units, or in the range of 1 to 5 units. As shown in the Examples below, these values ​​are significantly less than the differential gloss obtained from a comparative aqueous inkjet ink composition containing resin particles formed from a hydrophilic monomer (hydroxyethyl acrylate) instead of a dioxane / dioxolane monomer. Generally, a high T gThe relatively high T values ​​of the exemplary resin particles are associated with high gloss differential. g Considering the values ​​(80°C and 67°C), this result is surprising.

[0076] Aqueous inkjet ink compositions can be characterized by their waterfastness. Wet rub resistance, measured as described in the Examples below, provides a measure of waterfastness. In embodiments, aqueous inkjet ink compositions exhibit a wet rub resistance of at least 10, 15, or 20 when measured using ink droplets of about 4.5 ng, or at least 20, 25, or 30 when measured using ink droplets of about 9 ng. Again, generally, a high T g The relatively high T values ​​of the exemplary resin particles are associated with poor wet rub resistance. g Considering the values ​​(80°C and 67°C), this result is surprising.

[0077] Aqueous inkjet ink compositions can be characterized by their open-air stability. A measure of such stability is provided by observing the time it takes for an aqueous inkjet ink composition to gel upon exposure to air. This time can be measured as described in the Examples below. In embodiments, the time to gel is greater than 2 hours, greater than 3 hours, greater than 4 hours, or in the range of 3 to 5 hours. As shown in the Examples, the time to gel was extended by approximately 100% in an exemplary aqueous inkjet ink composition compared to a comparative aqueous inkjet ink composition containing resin particles formed from a hydrophilic monomer (hydroxyethyl acrylate) instead of dioxane / dioxolane monomers, and a comparative aqueous inkjet ink composition containing a water-soluble resin instead of resin particles. This is surprising, as hydrophilic monomers and water-soluble resins were expected to provide better open-air stability compared to resin particles based on amphiphilic dioxane / dioxolane monomers.

[0078] 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.

[0079] 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.

[0080] Any suitable substrate or recording sheet can be used as the final recording sheet.

[0081] The use of the present latex / resin particles is not limited to providing ink compositions. By way of example, given the adhesive properties of the resin particles described above, the latex can be used to provide an adhesive, generally in the form of a layer of resin particles on the surface of a substrate. Such a layer can be formed by applying any desired amount of any of the latexes described herein to a substrate, followed by removing water from the deposited latex to form the layer. Various thin-film deposition techniques can be used to apply the latex. Any desired substrate, such as paper, polymer, or the like, can be used. A second substrate can be applied over the layer to form a bonded article, i.e., two substrates adhered to each other via a substrate-to-substrate adhesive. Any of the additives disclosed above with respect to the ink composition can be included in the latex to achieve the desired adhesive properties. Useful additives can include surfactants, wetting agents, and viscosity-adjusting additives. Any of these additives described above can be used in the amounts described above. Other additives that can be used include tackifiers, such as rosin esters, rosin acids, and combinations thereof. Any of the exclusions described above with respect to the latex and ink composition can also apply to the adhesive embodiment. A latex that includes water, resin particles, and optionally additives and is configured to provide an adhesive may be referred to as a water-based adhesive composition. [Example]

[0082] 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. Examples 1 to 3

[0083] A reactive surfactant solution of 1.1 grams (Hitenol AR 1025 manufactured by Montello) and 35 grams of deionized water was prepared by mixing in a glass reactor. The reaction was then purged with nitrogen for 30 minutes. The reactor was then continuously purged with nitrogen while being stirred at 250 rpm. The reactor was then heated to 75°C and held there. Separately, 0.3 grams of ammonium persulfate (APS) initiator was dissolved in 5 grams of deionized water and added to the reactor.

[0084] Separately, a monomer emulsion was prepared in the following manner: styrene, butyl acrylate, methacrylic acid, sodium 4-styrenesulfonate (styrenesulfonic acid), dioxane / dioxolane monomer, 1-dodecanethiol (DDT), PEGDA 250, Hitenol AR 1025, and deionized water were mixed to form an emulsion. Different amounts of these components were used in each of Examples 1-3, as shown in Table 1. The emulsified mixture was slowly fed into the reactor over 2 hours, and the reaction was continued for 2 hours. An additional 0.15 g of APS initiator was dissolved in deionized water and added to the reactor over 10 minutes, and the reaction was continued for an additional 1.5 hours. The resulting latex was cooled to room temperature and neutralized to pH 8.0 with 2.5 M KOH solution.

[0085] The latex formulation is shown in Table 1 and the properties are shown in Table 2. Malvern Nano-ZS was used to synthesize D- (z、ave)、 D (v、50) (D 50 The latex was analyzed for resin particle size, including T, and polydispersity index (PDI). g was measured using a TA Instruments Discovery DSC 2500 in three successive cycles of heat-cool-heat at a rate of 10°C / min. g The value is relative to the resin particles of the latex. Example 4

[0086] In Example 4, the monomer emulsion of Example 2 was used in a different polymerization process. Specifically, a latex was prepared using seed emulsion polymerization. Once the monomer emulsion of Example 2 was prepared, 25 wt. % of the monomer emulsion was fed into a glass reactor at 0.5 mL / min. Then, 0.3 grams of ammonium persulfate (APS) initiator was dissolved in 5 grams of deionized water and added to the reactor over 10 minutes. This step created a seed for the polymerization. The polymerization was allowed to react for 30 minutes. The remaining emulsion was then fed into the reactor over 1.5 hours, and the reaction was allowed to continue for 2 hours. An additional 0.15 g of APS dissolved in DI water was then added to the reactor over 10 minutes, and the reaction was allowed to continue for an additional 1.5 hours. The latex was then cooled to room temperature and neutralized to pH 8.0 using a 2.5 M KOH solution. The latex formulation is shown in Table 1, and the properties are shown in Table 2. Example 5 (Comparative)

[0087] In Example 5, the procedure of Example 1 was repeated, except that hydrophilic hydroxyethyl acrylate (HEA) was used instead of the amphiphilic dioxane / dioxolane monomer. Colloidal silica was also used. The latex formulation is shown in Table 1, and the properties are shown in Table 2. Example 6 (Comparative)

[0088] In Example 6, the procedure of Example 1 was repeated, except that the amphiphilic dioxane / dioxolane monomer was replaced with hydrophilic hydroxyethyl acrylate. In addition, the ratio of styrene to butyl acrylate was changed. Colloidal silica was also used. The latex formulation is shown in Table 1, and the properties are shown in Table 2. Example 7 (Comparative)

[0089] In Example 7, the procedure of Example 1 was repeated, but without the dioxane / dioxolane monomer and without the hydroxyethyl acrylate. The latex formulation is shown in Table 1, and the latex properties are shown in Table 2.

[0090] [Table 1]

[0091] [Table 2] Examples 8 to 15

[0092] Aqueous inkjet ink compositions were formed using the latexes of Examples 1, 2, and 3, and Comparative Example 5. Another comparative aqueous inkjet ink composition was formed using a water-soluble resin and no resin particles. The aqueous inkjet ink compositions were formed using the following steps, and the formulations are shown in Table 3.

[0093] 1. The pigment dispersion was added to the deionized water and mixed for about 15 minutes at a speed of about 300 RPM using a Cowles blade impeller.

[0094] 2. The latex was slowly added to the pigment dispersion and mixed for approximately 20 minutes (Mixture A).

[0095] 3. In a separate beaker, the co-solvent, humectant, stabilizer, antifoaming agent, surfactant, and wetting agent were mixed to form a homogeneous mixture (Mixture B).

[0096] 4. Mixture B was slowly added to Mixture A. Once addition was complete, the ingredients were mixed for an additional 20 minutes.

[0097] 5. The wax was added and mixing continued for approximately another 15 minutes.

[0098] 6. After mixing, the aqueous inkjet ink composition was allowed to stand at room temperature for approximately 60 minutes before checking the pH, conductivity, and surface tension.

[0099] [Table 3]

[0100] The inkjet ink compositions were jetted onto different paper substrates, including Kodak Photo Paper, McCoy® Glossy #100, and Xerox® Bold, using a Dimatix DMP2800 printer. The first set of key test parameters used was as follows: drop weight = 4.5-4.8 ng (i.e., approximately 4.5 ng), drop velocity = 6-7 m / s, frequency = 5 kHz, voltage = 16-20 V, and print temperature = 20°C-40°C. The second set of key test parameters used was as follows: drop weight = 8.5-9 ng (i.e., approximately 9 ng), drop velocity = 9-11 m / s, frequency = 5 kHz, voltage = 24-27 V, and print temperature = 20°C-40°C. Printing parameters were 600 x 600 dpi printing. Measurements were performed using a PIAS II instrument, 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, approximately 5 μm / pixel, was used to measure dot size and diameter. The results are shown in Table 4. The aqueous inkjet ink compositions made using the latexes of Examples 1-3 passed continuous jetting for >10-30 minutes without faceplate cleanliness or nozzle clogging. The ink droplets also maintained their spherical and circular shape.

[0101] The stability of aqueous inkjet ink compositions in open air was examined by visual assessment of the onset of structure formation, gelation state, and fully gelled ink. For each study, 4 grams of the test ink, along with the control ink, was dispensed into identical Pyrex Petri dishes (60 mm diameter, 10 mm height) in a laboratory space (32% relative humidity, 22°C) and inspected every 30 minutes for the entire 5-hour test period. At each inspection interval, the ink dish was gently rotated to assess the severity of structure formation.

[0102] The aqueous inkjet ink compositions were tested for wet rub resistance (20 double rubs using a wet Q-tip) (waterfastness). A thin layer (wire-wound rod RDS2.5) of each inkjet ink composition was coated onto McCoy glossy #100 paper and then dried in a convection oven at 130° C. for 2 minutes. The numbers in Table 4 indicate the number of double rubs (average of 3 measurements) obtained before any removal of ink was observed.

[0103] To determine the gloss difference value, gloss measurements were taken for the aqueous inkjet ink composition. A BYK Gardner Micro Gloss meter (75°) was used to measure the gloss on the coated paper substrate. Once the ink is printed on the paper substrate, the print is left to stand for 24 hours. The gloss at 75° is measured with a digital micro gloss meter. The print is then rubbed with a wipe 30 times and the gloss is measured again. The gloss difference before and after the 30 wipes is calculated. The lower the gloss difference, the better the quality of the print fastness to rubbing.

[0104] [Table 4]

[0105] As shown in Table 3 (Examples 1-4), the incorporation of amphiphilic dioxane / dioxolane monomers did not adversely affect the microemulsion polymerization, the monomer emulsification process, and the final conversion. Also, the resin particle size distribution (PDI<0.05) and colloidal stability after accelerated aging tests (3 days at 60 °C) were maintained.

[0106] In particular, the latex / resin particles of Examples 1 to 4 exhibited pH responsiveness. For example, the resin particles of the latex of Example 3 exhibited a pH responsiveness of D 50The latex of Example 3 showed a 25% increase in particle size. Similarly, the latex of Example 3 showed an almost five-fold increase in viscosity. A tuning fork vibration viscometer (Cole-Parmer) was used to measure viscosity. At 40% solids, room temperature, and pH 3, the viscosity was 37 cP, and at 34.4% solids, room temperature, and pH 8, the viscosity increased to 176 cP. At the same time, the colloidal stability and particle size distribution of Examples 1-4 were maintained when the pH was adjusted.

[0107] The aqueous inkjet ink compositions of Examples 8-12 (made using the latex / resin particles of Examples 1-3) exhibited excellent print performance, showing improved jetting (>30 minutes, no misdirectional or satellite jetting), latency, and decap times. More specifically, the printed images of aqueous inkjet ink compositions of Examples 10 and 11 (made using the latex / resin particles of Example 2) exhibited good circularity and lines, and the solid blocks exhibited similar or better surface coverage than Comparative Examples 13-15.

[0108] In addition, the use of dioxane / dioxolane monomers dramatically improved the mechanical properties of the printing ink, as evidenced by increased water resistance (wet rub resistance) and reduced gloss differential (see Table 4). This is due to the T of the resin particles in Examples 9 and 11. g This is particularly surprising because the T g Values ​​are usually associated with poor wet rub resistance and high gloss differential, as in the case of Comparative Example 14.

[0109] Finally, the use of dioxane / dioxolane monomers significantly improved the open-air stability of aqueous inkjet ink compositions. Aqueous inkjet ink compositions Examples 8-12 (made from the latex / resin particles of Examples 1-3) exhibited extended flow times and delayed the onset of structure formation (gelation) when exposed to open air. Specifically, they showed at least a 1-2 hour improvement in the onset and progression of gelation. This represents an improvement of over 100% over Comparative Examples 13-15. This is particularly surprising because the resin particles of Examples 13 and 14 contain hydrophilic hydroxyethyl acrylate, and Example 15 contains a water-soluble resin (PEG 4000). These components were expected to suppress gelation compared to the amphiphilic dioxane / dioxolane monomers of Examples 8-12.

[0110] 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."

[0111] 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.

[0112] 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.

Claims

1. An ink composition comprising water, resin particles, a colorant, and optionally a wax, wherein the resin particles comprise a polymerization product of a reactant comprising a dioxane / dioxolane monomer and an additional monomer, and the dioxane / dioxolane monomer is an ester of (meth)acrylic acid and an alcohol containing a dioxane moiety, an ester of (meth)acrylic acid and an alcohol containing a dioxolane moiety, or both, and the water is present in an amount of at least about 50% by weight.

2. The ink composition according to claim 1, wherein the alcohol containing the dioxane moiety or the alcohol containing the dioxolane moiety is an acetal of a triol, a ketal of a triol, or a carbonate of a triol.

3. The ink composition according to claim 2, wherein the triol is glycerol or trimethylolpropane.

4. The dioxane / dioxolane monomer has the formula I or formula II, 【Chemical 1】 wherein R is selected from the group consisting of hydrogen and methyl, R' is selected from the group consisting of hydrogen and ethyl, and Z is selected from the group consisting of hydrogen, the oxygen of a carbonyl group, an alkyl group, an aryl group, and an alkoxy group. The ink composition according to claim 1.

5. The ink composition according to claim 1, wherein the dioxane / dioxolane monomer is selected from the group consisting of glycerol formal (meth)acrylate, trimethylolpropane formal (meth)acrylate, isopropylidene glycerol (meth)acrylate, and combinations thereof.

6. The ink composition according to claim 1, wherein the dioxane / dioxolane monomer is glycerol formal (meth)acrylate.

7. The resin particles have a particle size D that depends on the pH of a latex containing water and the resin particles, and the ink composition according to claim 1. 50 ​

8. The resin particles have a particle size of about 90 nm or less at a pH of about 3, and the ink composition according to claim 1. 50 ​

9. The ink composition according to claim 1, which does not have silica particles, a water-soluble resin or an emulsion thereof, an aqueous binder, a polymer dispersant, and combinations thereof.

10. The ink composition according to claim 1, exhibiting a gloss difference of less than about 5 units, a wet rub resistance of at least about 10 when measured using about 4.5 ng of the ink composition, or both.

11. The ink composition according to claim 1, exhibiting a time to gelation of at least about 2 hours upon exposure to air.

12. The ink composition according to claim 1, wherein the ink composition is an aqueous inkjet ink composition.

13. The ink composition according to claim 1, wherein the reactant further comprises styrene, alkyl (meth)acrylate, an acidic monomer, and a reactive surfactant, and one of these is the additional monomer.

14. An ink composition comprising water, resin particles, a colorant, and optionally a wax, wherein the resin particles comprise a polymerization product of a reactant comprising a dioxane / dioxalane monomer and an additional monomer, and the dioxane / dioxalane monomer is glycerol formal (meth)acrylate.

15. The ink composition according to claim 14, wherein the ink composition further comprises styrene; alkyl (meth)acrylate; and methacrylic acid, styrene sulfonic acid, or both methacrylic acid and styrene sulfonic acid, and one of these is the additional monomer, and further a reactive surfactant; a polyfunctional monomer; and optionally, a chain transfer agent, an initiator, or both a chain transfer agent and an initiator The ink composition according to claim 14.

16. Glycerol formal (meth)acrylate is present in an amount of about 2% to about 18% by weight; Styrene and alkyl (meth)acrylate are present in a combined amount of about 70% to about 97% by weight; Methacrylic acid, styrene sulfonic acid, or both methacrylic acid and styrene sulfonic acid are present in a combined amount of about 2% to about 20% by weight; The polyfunctional monomer is present in an amount of about 0.001% to about 1% by weight. The ink composition according to claim 15.

17. The resin particles consist of the polymerization product of the reactant, The reactant consists of glycerol formal (meth)acrylate; styrene; alkyl (meth)acrylate; methacrylic acid, styrene sulfonic acid, or both methacrylic acid and styrene sulfonic acid; a reactive surfactant; a polyfunctional monomer; and optionally, a chain transfer agent, an initiator, or both a chain transfer agent and an initiator. The ink composition according to claim 16.

18. The ink composition according to claim 17, wherein the ink composition is an aqueous inkjet ink composition.

19. An ink composition comprising water, resin particles, a colorant, and optionally a wax, wherein the resin particles comprise a polymerization product of a reaction product comprising a dioxane / dioxalane monomer and an additional monomer, and the dioxane / dioxalane monomer is an ester of (meth)acrylic acid and an alcohol containing a dioxane moiety, an ester of (meth)acrylic acid and an alcohol containing a dioxalane moiety, or both. The ink composition exhibits a gloss difference of less than about 5 units, a wet rub resistance of at least about 10, or both, when measured using about 4.5 ng of the liquid application of the ink composition.

20. An ink composition comprising water, resin particles, a colorant, and optionally a wax, wherein the resin particles comprise a polymerization product of a reaction product comprising a dioxane / dioxalane monomer and an additional monomer, and the dioxane / dioxalane monomer is an ester of (meth)acrylic acid and an alcohol containing a dioxane moiety, an ester of (meth)acrylic acid and an alcohol containing a dioxalane moiety, or both. The reaction product further comprises styrene, an alkyl (meth)acrylate, an acidic monomer, and a reactive surfactant, and one of these is the additional monomer.

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