Ink composition containing 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 in aqueous inkjet ink compositions is often synthesized by emulsion polymerization 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 latex resin particles act as a binder, helping to form a water-permeable polymer film that protects the printed image. To adjust the viscosity of the aqueous inkjet ink composition, water-soluble resins are often added. However, water-soluble resins can induce coagulation and aggregation of resin particles and inhibit their electrostatic stability. Water-soluble resins also reduce the water fastness of images printed from aqueous inkjet ink compositions. [Overview of the Initiative]

[0002] This disclosure provides latex 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 resin particles exhibit pH responsiveness, which is utilized to provide improved latex and related compositions. For example, embodiments of the resin particles have a pH-dependent size, including exhibiting a larger size at higher pH values. The viscosity of latex containing such resin particles is also pH-dependent, including exhibiting a higher viscosity at higher pH values. This feature makes it possible to synthesize resin particles at low pH values ​​and low viscosity. Ink compositions can then be prepared with a desired viscosity at higher pH values ​​using relatively small amounts of resin particles. Furthermore, although they can be used, water-soluble resins or silica additives are not required for viscosity adjustment. Given this unique pH responsiveness, embodiments of the resin particles, latex, 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 open-air waste trays in aqueous inkjet systems. Finally, the resin particle embodiment also has a relatively high glass transition temperature (T g ) indicates high T for stability, scratch resistance, reduced tackiness, and offset transfer. g While a high T value is desirable, this property is also known to negatively affect gloss difference and adhesion. Surprisingly, high T g The ink composition, including the resin particle embodiment, exhibits excellent water resistance, low gloss difference, and high adhesion.

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

[0004] Other key features and advantages of this disclosure will become apparent to those skilled in the art upon consideration of the following drawings, modes for carrying out the invention, and the appended claims. [Modes for carrying out the invention]

[0005] latex

[0006] In one embodiment, a latex is provided. Such a latex comprises resin particles, which are synthesized from various monomers to form a polymer material, from which resin particles are composed. At least one type of monomer is used, which is an ester of (meth)acrylic acid with an alcohol containing a dioxane moiety or an alcohol containing a dioxolane moiety. (For example, the use of "(meth)" as 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 monomers that are esters of (meth)acrylic acid with an alcohol containing a dioxane moiety, monomers that are esters 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. Alcohols containing the dioxane / dioxolane moiety may be triol acetals, triol ketals, or triol carbonates. Exemplary triols include glycerol and trimethylolpropane. Triols may be unsubstituted or substituted. "Substituted" means that one or more bonds to carbon or hydrogen are substituted by bonds to non-hydrogen and non-carbon atoms. Dioxane / dioxolane monomers may have formulas 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, carbonyl oxygen, alkyl, aryl, and alkoxy groups. Either or both types of monomers may be used in resin particles. [ka]

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

[0008] Examples of 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 It has a temperature range of approximately 85-90°C. In this disclosure, the name “glycerol formal (meth)acrylate” (and the names of other dioxane / dioxolane monomers described in this paragraph) refers to either or both dioxane isomers and dioxolane isomers. That is, all possibilities are encompassed by the name.

[0009] At least some embodiments of dioxane / dioxolane monomers are amphiphilic. This is in contrast to hydrophilic monomers, which have a high affinity for polar solvents such as water, but a 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, for example, 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; and β-carboxyethyl acrylate. Acrylic (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; vinylidenes such as vinylidene chloride and vinylidene chlorofluoride; N-vinylindole; N-vinylpyrrolidone; methacrylate; acrylamide; methacrylamide; vinylpyridine; vinylpyrrolidone; vinyl-N-methylpyridinium chloride; vinylnaphthalene; p-chlorostyrene; vinyl chloride; vinyl bromide; vinyl fluoride; ethylene; propylene; butylene; and isobutylene. Different combinations of these monomers may be used. In the embodiment, 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. Therefore, the alkyl group of the alkyl (meth)acrylate may have one or more carbon atoms, two or more carbon atoms, four or more carbon atoms, or one to six carbon atoms.

[0011] Acidic monomers can be used to form 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, styrenesulfonic acid, vinyl sulfonate, cyanoacrylic acid, vinyl acetic acid, allyl acetic acid, ethylidine acetic acid, propylidine acetic 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, aconitic acid, phenylacrylic acid, acryloxypropionic acid, vinyl benzoic acid, N-vinyl succinamic acid, mesaconic acid, methacryloyl alanine, acryloyl hydroxyglycine, sulfoethyl methacrylic acid, sulfopropyl acrylic acid, styrenesulfonic acid, sulfoethyl acrylic acid, 2-methacryloyloxy methane-1-sulfonic acid, 3-methacryloyloxy propane-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-propane sulfonic acid, and combinations thereof. These acidic monomers also include their salts, for example, salts of sulfonic acid.

[0012] In an embodiment, two different acidic monomers are used to form resin particles each having a different pK a value. The pK a values of the two different acidic monomers may differ from each other by at least 2 units, at least 3 units, at least 4 units, or at least 5 units. In an embodiment, the two different acidic monomers are an acidic monomer having a higher pK a in the range of 0.1 to 10 and a lower pK aIt is present in the monomer emulsion used to form resin particles in a weight ratio with an acidic monomer having this. This includes the ranges of 0.5 to 8 and 1 to 6. In an embodiment, two different types of acidic monomers, including methacrylic acid and sulfonic acid, are used to form resin particles.

[0013] Polyfunctional 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 for promoting crosslinking within the resin particles. Exemplary polyfunctional monomers include difunctional monomers such as poly(ethylene glycol) diacrylate, for example, poly(ethylene glycol) diacrylate with a molecular weight of 250 g / mol. Other poly(ethylene glycol) di(meth)acrylates may be used, including those with molecular weights in the ranges of 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; compounds obtained by substituting the acrylate of these compounds with methacrylate; 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; and compounds obtained by substituting the acrylate of these compounds with methacrylate.Other bifunctional monomers include diene compounds such as isoprene and butadiene, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene, diacrylate compounds bonded to 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 the acrylate of these compounds with methacrylate. Polyfunctional monomers include pentaerythritol triacrylate, trimethylolmethane triacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, oligoester acrylates, and compounds obtained by substituting the acrylate of these compounds with methacrylate.

[0014] Reactive surfactants can be used to form resin particles. Suitable reactive surfactants contain polymerizable (and therefore reactive) groups that can be incorporated into the resin particles. Exemplary reactive surfactants include anionic ether sulfate reactive surfactants, such as those from the commercially available Hitenol series, including Hitenol AR10-25. Other suitable reactive surfactants include polyoxyethylene alkylphenyl ether ammonium sulfate, Hitenol BC-10, BC-20, BC10-25, BC-2020, BC-30; polyoxyethylene styrene-phenyl ether ammonium sulfate containing Hitenol AR-10, AR-20, AR-2020; nonionic polyoxyethylene alkylphenyl ethers containing 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] Chain transfer agents can be used to form 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. Carbon tetrabromide, carbon tetrachloride, and halogenated carbons such as combinations thereof can be used as chain transfer agents.

[0016] In embodiments, certain monomers can be excluded when forming resin particles. Monomers to be excluded can include 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 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, including achieving the values of the properties described below. Exemplary amounts are provided below.

[0018] Dioxane / dioxolane monomers can be used in the monomer emulsion in amounts ranging from 1 wt% to 40 wt%, 1 wt% to 30 wt%, 1 wt% to 20 wt%, 2 wt% to 18 wt%, and 5 wt% to 15 wt%. (Here, wt% = (total weight of dioxane / dioxolane monomers) / (total weight of monomers in the monomer emulsion excluding the reactive surfactant) *(Refers to 100). Acidic monomers may be used in monomer emulsions in amounts ranging from 2% to 20% by weight and 5% to 15% by weight. (The weight percentage has a similar meaning to that described for dioxane / dioxolane monomers.) As described above, different pK a Two different types of acidic monomers having values ​​may be used in the weight ratios described above. Polyfunctional monomers, including difunctional monomers, may be used in monomer emulsions 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. (Weight percent has a similar meaning to that described for 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. (Weight percent has a similar meaning to that described for dioxane / dioxolane monomers.) If 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 from 15% to 30% by weight.

[0019] Reactive surfactants can be used in monomer emulsions in amounts ranging from 1.5% to 6.5% by weight. (where weight % is (total weight of reactive surfactant) / (total weight of monomers in the monomer emulsion containing the reactive surfactant monomer) * (Refers to 100). This range includes 1.5% by weight 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, 0.25% to 2.5% by weight. (where wt% is (total weight of chain transfer agent) / (total weight of monomers in the monomer emulsion excluding reactive surfactants) * (It refers to 100.)

[0021] In the embodiment, the monomer emulsion comprises (or consists of) a solvent, a dioxane / dioxolane monomer, and additional monomers. In the embodiment, the additional monomers are acidic monomers (e.g., methacrylic acid, sulfonic acid, or both). In the embodiment, at least two additional monomers, relatively high T g monomers (e.g., styrene or methyl methacrylate) and relatively low T g The monomers include (e.g., alkyl acrylates such as butyl acrylate). In embodiments, polyfunctional monomers are included. In embodiments, the monomer emulsion includes (or consists of) a solvent, a 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 bifunctional 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 monomers, reactive surfactants, and chain transfer agents may be used as described above. The remainder may consist of a solvent.

[0022] In some embodiments, the monomer emulsion is surfactant-free (i.e., does not contain surfactants). However, in other embodiments, surfactants may be used. Here, “surfactant” refers to non-reactive, non-polymerizable anionic surfactants such as sodium dodecylsulfate (SDS), sodium dodecylbenzenesulfonate, sodium dodecylnaphthalene sulfate; dialkylbenzenealkyl sulfates; palmitic acid; alkyldiphenyl oxide disulfonates; and branched sodium dodecylbenzenesulfonate. “Surfactant” also refers to non-reactive, non-polymerizable cationic surfactants such as alkylbenzyldimethylammonium chloride, dialkylbenzenealkylammonium chloride, lauryltrimethylammonium chloride, alkylbenzylmethylammonium chloride, alkylbenzyldimethylammonium bromide, benzalkonium chloride, cetylpyridinium bromide, trimethylbromide, quaternary polyoxyethylalkylamine halide salts, and dodecylbenzyltriethylammonium chloride. "Surfactants" also refer 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.

[0023] In this embodiment, the monomer emulsion does not contain (i.e., does not include) silica particles. Although silica particles have been used to increase viscosity, this embodiment of resin particles can achieve high viscosity in latex even without including such silica particles. Commercially available silica particles that may be excluded include: 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, as well as 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, including monomer-deficient emulsion polymerization, conventional emulsion polymerization, suspension polymerization, miniemulsion polymerization, nanoemulsion polymerization, seed emulsion polymerization, and microemulsion polymerization, can be used to form resin particles. These polymerization techniques may use any of the monomer emulsions described above. An exemplary monomer-deficient emulsion polymerization process is described below. However, as mentioned above, other processes may be used. (See also Example 4, which describes an exemplary seed emulsion polymerization process.)

[0025] An exemplary method for preparing a latex containing resin particles involves adding one of the monomer emulsions described above to a reactive surfactant solution at a certain supply rate over a period of time. The reactive surfactant solution comprises a solvent and a reactive surfactant. Any of the solvents and reactive surfactants described above may be used. The reactive surfactant in the reactive surfactant solution may be of the same or different type as the reactive surfactant that may be present in the monomer emulsion. The reactive surfactant solution may further contain a buffer. Various buffers such as sodium bicarbonate, sodium carbonate, and ammonium hydroxide may be used. The reactive surfactant may be used in amounts ranging from 1% to 10% by weight and 2% to 5% by weight. (where wt% is (total weight of reactive surfactant) / (total weight of reactive surfactant solution)) * (Refers to 100.) The buffer solution can be used in amounts ranging from 0.25% by weight to 2.5% by weight. (Wt% has the same meaning as described above.)

[0026] The reactive surfactant solution may contain an initiator. Alternatively, a separate initiator solution containing the initiator and one of the solvents described above may be formed and added to the reactive surfactant solution. The separate initiator solution may be added before the monomer emulsion is added. Additional amounts of the separate initiator solution may be added after the monomer emulsion is added. Examples of suitable initiators include water-soluble initiators such as ammonium persulfate (APS), sodium persulfate, and potassium persulfate, as well as organic soluble initiators containing 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-methylpropionamidine]dihydrochloride, 2,2'-azobis[N-(4-aminophenyl)-2-methylpropionamidine]tetrahydrochloride, 2,2'-azobis[2-methyl-N(phenylmethyl)propionamidine]dihydrochloride, 2,2'-azobis[2-methyl-N-2-propenylpropionamidine]dihydrochloride, and 2,2'-azobis[N-(2-hydroxy-ethyl)2-methylpropion 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-diazepine-2-yl)propane]dihydrochloride, 2,2'-azobis[2-( Examples include 3,4,5,6-tetrahydropyrimidine-2-yl)propane]dihydrochloride, 2,2'-azobis[2-(5-hydroxy-3,4,5,6-tetrahydropyrimidine-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 wt% is (total weight of initiator) / (total weight of reactive surfactant solution)). * (It refers to 100.)

[0027] In some embodiments, the reactive surfactant solution comprises (or consists of) a solvent (e.g., water), a reactive surfactant, and optionally one or more initiators and buffers. In any of these embodiments, the amounts of reactive surfactant, initiator, and buffer may be used as described above. The remainder may consist of a solvent. In at least some embodiments, the reactive surfactant solution does not contain any of the surfactants described above. In at least some embodiments, the reactive surfactant solution does not contain any of the silica particles described above. As a result, the resin particles may be characterized by not containing any of the surfactants and / or silica particles described above. In at least some embodiments, the reactive surfactant solution does not contain any monomers other than the reactive surfactant monomers present in the solution.

[0028] The addition of monomer emulsions to reactive surfactant solutions can be carried out under the influence of an inert gas (e.g., nitrogen) and at high temperatures (e.g., temperatures higher than room temperature, such as in the range of 50°C to 90°C). This can be achieved by purging with an inert gas and heating the reactive surfactant solution before adding the monomer emulsion, and continuing this heating during the addition of the monomer emulsion.

[0029] As described above, the monomer emulsion is added at a supply rate over a set period of time. In the presence of an initiator, the monomers of the monomer emulsion undergo polymerization to form resin particles of high-viscosity latex. The supply rate is slow enough so that polymerization is carried out under "monomer-deficient" conditions. This means that the supply rate is less than or equal to the rate of polymerization, for example, the rate between styrene and acrylate monomers. Exemplary supply rates range from 1 mL / min to 10 mL / min based on a total reaction volume of 1 L. Exemplary periods include those ranging from 60 minutes to 600 minutes. After the addition of the monomer emulsion, polymerization can be continued for a further period with or without the addition of further initiators. Exemplary additional periods range from 1 hour to 18 hours. Both the addition of the monomer emulsion and the polymerization after addition can be carried out under an inert gas and at high temperatures. Optionally, the formed latex can be treated by standard techniques such as solidification, dissolution, precipitation, filtration, washing, or drying. Treated or untreated latex may be used to form the ink compositions described below.

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

[0031] This method may further include forming a monomer emulsion, forming a reactive surfactant solution, and / or forming an initiator solution. Each of these may be formed by combining and mixing desired components in desired amounts.

[0032] The composition of the resin particles depends on the selection of monomers, their relative amounts, and the polymerization reaction between the selected monomers that produces the polymerization product as described above. Therefore, a variety of compositions are encompassed, including those based on various polymerization products of reactants containing various monomer combinations. As stated above, the reactants contain dioxane / dioxolane monomers, but otherwise the selection of other monomers is not particularly limited. For clarity, the composition of the resin particles can be determined by referring to the monomers being polymerized and recognizing that the chemical forms of these monomers generally change as a result of the polymerization reaction. In embodiments, the resin particles contain (or consist of) a polymerization product (e.g., copolymer) of a reactant containing dioxane / dioxolane monomers and additional monomers. In embodiments, the resin particles contain (or consist of) a polymerization product (e.g., copolymer) of a reactant containing dioxane / dioxolane monomers, additional monomers, and polyfunctional monomers. In these embodiments, the resin particles comprise (or consist of) a polymerization product (e.g., copolymer) of a reaction comprising dioxane / dioxolane monomer, styrene, alkyl acrylate (e.g., butyl acrylate), acidic monomer (methacrylic acid, sulfonic acid, or both), polyfunctional monomer (e.g., a bifunctional monomer such as poly(ethylene glycol) diacrylate), and a reactive surfactant (e.g., anionic ether sulfate). In each of these embodiments, an initiator (or a portion thereof) may be incorporated into the start and end of each polymer chain in the resin particles. In each of these embodiments, the resin may be crosslinked due to the polyfunctional / bifunctional 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 may range from 1% to 40% by weight in the resin particles. As stated above, this weight percentage is calculated as (total weight of dioxane / dioxolane monomers) / (total weight of monomers in resin particles excluding reactive surfactants). * It refers to 100.

[0033] Using certain exemplary compositions, the composition of resin particles may 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, different chemical parts resulting from polymerization reactions are identified by referring to the corresponding monomers in parentheses, where "ran" refers to the random incorporation of different monomers into the copolymer. Use of this description includes the presence of an initiator (or a portion thereof) at the origin of each copolymer, as well as crosslinking via polyfunctional / bifunctional monomers.

[0034] In embodiments where certain monomers are excluded from forming resin particles, such monomers do not participate in the polymerization reaction and instead form the polymer matrix of the resin particles. Therefore, in these embodiments, the resin particle composition may be described as not having (i.e., not containing) one or more of the following silyl ester monomers: vinyl-imidazolium monomer, urethane (meth)acrylate monomer, and triisopropylsilyl (meth)acrylate.

[0035] In embodiments, the latex may be described as having no (i.e., not containing) any resin / polymer other than that provided by the resin particles themselves. This includes not having polyurethane, polyurethane (meth)acrylate, poly(meth)acrylate (other than the resin particles themselves), polyester, silyl ester copolymer, silyl (meth)acrylate polymer, or any combination thereof.

[0036] Since the resin / polymer constituting the resin particles is already polymerized, latex itself is generally not curable and therefore does not contain (i.e., does not contain) an initiator. This does not rule out the presence of small amounts of unreacted or reacted initiators that may be incorporated into the polymer chain. Similarly, latex may be described as not containing (i.e., not containing monomers).

[0037] In embodiments, the latex may also be described as being free from (i.e., not containing) fungicides / biocides such as medetomidine.

[0038] The water content of the latex may be at least 40% by weight. This includes at least 50% by weight and at least 60% by weight. These weight percentages refer to the weight of water compared to the total weight of the latex.

[0039] In the embodiment, the resin particles have a core / shell configuration. Core / shell resin particles can be formed using seed emulsion polymerization, where 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 also be used to form resin particles in which the seed monomer emulsion and the feed monomer emulsion have the same composition.

[0040] Resin particles can be characterized by their size. The particle size is D 50 This may be reported as particle size, meaning that 50% (by volume) of the sample consists of particles with a diameter less than the stated diameter value. 50 Particle size can be measured using a Malvern Zetasizer Nano ZS. For verification of light scattering techniques and methods, NIST polystyrene nanosphere control samples with diameters in the range of 20 nm to 200 nm, available from Microspheres-Nanospheres (Corpuscular company of Microtrac) or third-party vendors (such as ThermoFisher Scientific), may be used. Since at least the resin particles have a pH-dependent size, the size can be reported with respect to a specific pH. In the embodiment, the resin particles are measured at a pH of 3. 50 D at pH 8, which is larger than the particle size. 50Characterized by particle size, which includes 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, D at pH 3 50 The particle size is in the range of 100 nm or less, 90 nm or less, 80 nm or less, 70 nm or less, or 60 nm to 90 nm.

[0041] Latex containing these resin particles may be characterized by their viscosity. Viscosity values ​​may refer to specific temperatures and specific solid content and may be measured using a tuning fork vibratory viscometer (Cole-Parmer), as described in the following examples. Furthermore, since at least embodiments of the resin particles make the latex pH-dependent, viscosity may be reported with respect to a specific pH. In embodiments, the latex containing the resin particles is characterized by a viscosity at room temperature, 30% solid content, and pH 8 that is greater than the viscosity at room temperature, 30% solid content, and pH 3. This includes being twice, three times, four times, five times, or two to ten times greater. In embodiments, the viscosity at room temperature, 30% solid content, 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 and are measured within one day of latex formation.

[0042] These resin particles also have their T g Values ​​can be a characteristic. g The values ​​can be measured using a Differential Scanning Calorimetry (DSC) TA Instruments Discovery DSC 2500 as described in the following embodiments. In some embodiments, T g This range is approximately 50°C to 100°C. This includes the ranges of 50°C to 90°C and 50°C to 80°C.

[0043] Ink composition

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

[0045] Resin particles may be present in the aqueous inkjet ink composition in amounts ranging from 1% to 10% by weight and 5% to 10% by weight. (where weight % is (total weight of resin particles) / (total weight of aqueous inkjet ink composition)) * (Refers to 100.) This range includes 5% to 10% by weight. Various other components can be used to form the aqueous inkjet ink compositions described below.

[0046] Solvent system

[0047] Aqueous inkjet ink compositions contain a water-based solvent system. The solvent system may consist solely of water or may include a mixture of water and a water-soluble and / or water-miscible organic solvent. Water-soluble and water-miscible organic solvents may be referred to herein as cosolvents 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 glycerols, and ethoxylated glycerols. Exemplary 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, ureas, substituted ureas such as thiourea, ethyleneurea, alkylurea, alkylthiourea, dialkylurea, and dialkylthiourea, carboxylic acids and their salts such as 2-methylpentanoic acid, 2-ethyl-3-propylacrylic acid, 2-ethylhexanoic acid, 3-ethoxypropionic acid, esters, organic sulfides, organic sulfoxides, sulfones (such as sulfolanes), carbitols, butylcarbitols, cellusolve, ethers, and Examples include repropylene glycol monomethyl ether, ether derivatives, hydroxy ethers, 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, and inositol, as well as 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 of hydrocarbons having 4 to 7 carbon atoms. 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 the embodiment, the solvent system includes water, a 1,2-alcohol (e.g., 1,2-hexanediol), a glycol (e.g., 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 and viscosity. In embodiments, the weight ratio of water to organic solvent is 90:10 to 51:49. If more than one organic solvent is used, these weight ratios refer to the total amount of organic solvents. Since water may be present in latex, colorants, etc., these weight ratios refer to the total amount of water.

[0051] Similarly, various total amounts of solvent systems can be used in aqueous inkjet ink compositions. In embodiments, the solvent system is present in amounts of 50% to 95% by weight, 60% to 90% by weight, or 65% to 90% by weight. (where weight % is (total weight of solvent system) / (total weight of aqueous inkjet ink composition)) * (Refers to 100.) In this embodiment, 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. (Here, weight % is (total weight of water) / (total weight of aqueous inkjet ink composition) * (It refers to 100.)

[0052] Coloring agents

[0053] Water-based inkjet ink compositions may contain colorants. 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 colorants such as black No. 1, black No. 2, red No. 40, blue No. 1, and yellow No. 7, FD&C dyes, acid black dyes (No. 1, 7, 9, 24, 26, 48, 52, 58, 60, 61, 63, 92, 107, 109, 118, 119, 131, 140, 155, 156, 172, 194), acid red dyes (No. 1, 8, 32, 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 Dye (No. 1, 6, 8, 14, 15, 25, 71, 76, 78, 80, 86, 90, 106, 108, 123, 163, 165, 199, 226), Direct Red Dye (No. 1, 2, 16, 23, 24, 28, 39, 62, 72, 236), Direct Yellow Dye (No. 4, 11, 12, 27, 28, 33, 34, 39, 50, 58, 86, 1 Examples include reactive dyes such as 00, 106, 107, 118, 127, 132, 142, 157), reactive red dyes (No. 4, 31, 56, 180), reactive black dye (No. 31), and reactive yellow dye (No. 37), as well as anthraquinone dyes, monoazo dyes, disazo dyes, phthalocyanine derivatives including various phthalocyanine sulfonates, aza(18)annulene, formazan copper complexes, and triphenodioxazine.

[0054] Examples of suitable pigments include black pigment, cyan pigment, magenta pigment, and yellow pigment. The pigment may be organic or inorganic particles. A suitable inorganic pigment is carbon black. However, other inorganic pigments such as cobalt blue (CoO-Al2O3), chrome yellow (PbCrO4), iron oxide, and titanium dioxide (TiO2) may be suitable. Suitable organic pigments include, for example, 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, pyrantron pigments, and quinophthalone pigments), insoluble dye chelates (e.g., basic dye type chelates and acid dye type chelates), nitro pigments, nitroso pigments, and anthanthrone pigments such as PR168. Representative examples of phthalocyanine blue and green include copper phthalocyanine blue, copper phthalocyanine green, and their derivatives (pigment blue 15, pigment green 7, and pigment green 36). Representative examples of quinacridone 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 anthraquinone include pigment red 43, pigment red 194, pigment red 177, pigment red 216, and pigment red 226. Representative examples of perylene 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 press cake form from many suppliers, including BASF Corporation, Engelhard Corporation, and Sun Chemical Corporation. Examples of usable black pigments include carbon pigments. Carbon pigments can be any commercially available carbon pigment that provides acceptable optical density and printing properties. Suitable carbon pigments for use in this system and method include, but are not limited to, carbon black, graphite, glassy carbon, charcoal, and combinations thereof. Such carbon pigments can be manufactured by various known methods, such as the channel process, contact process, furnace process, acetylene process, or thermal process, and are commercially available from such suppliers such as Cabot Corporation, Columbian Chemicals Company, Evonik, and EIDuPont 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®, and BLACK. Examples of pigments include, but are not limited to, those manufactured by Cabot, such as PEARLS®, ELFTEX®, MOGUL®, and VULCAN® pigments; pigments manufactured by Columbia, such as RAVEN® 5000 and RAVEN® 3500; and pigments manufactured by Evonik, 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 microparticles, small molecule-attached pigment microparticles, self-dispersing pigment microparticles, and polymer-dispersed pigment microparticles.

[0056] When forming an aqueous inkjet ink composition, the colorant may be provided as a colorant dispersion containing the colorant and a solvent (e.g., water). The colorant may also 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 colorants can be used in aqueous inkjet ink compositions. However, generally, the amount is selected such that the total solids content of the aqueous inkjet ink composition (generally provided by resin particles, colorants, and wax, if present) is 5% to 15% by weight, 6% to 12% by weight, or 7% to 10% by weight. (where weight % is (total weight of solids) / (total weight of aqueous inkjet ink composition)) * (It refers to 100.)

[0058] wax

[0059] Aqueous inkjet ink compositions may contain waxes. Examples of waxes include paraffin wax, polyethylene wax, polypropylene wax, microcrystalline wax, polyolefin wax, montan ester wax, and carnauba wax. Waxes with melting points in the range of 50°C to 150°C may be used. Nanoscale wax emulsions (e.g., with diameters of 1000 nm or less, 500 nm or less, or 100 nm or less) based on carnauba wax and paraffin wax may be used. Michelman waxes may be used (e.g., Michem Lube 103DI, 124, 124P135, 156, 180, 182, 190, 270R, 368, 511, 693, 723, 743, 743P, and 985, as well as 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, including Aquacer 2500, Aquacer 507, Aquacer 513, Aquacer 530, Aquacer 531, Aquacer 532, Aquacer 535, Aquacer 537, Aquacer 539, and Aquacer 593, may also be used. In embodiments, the wax is an anionic nanoscale wax emulsion such as Michem Lube 190.

[0060] Various amounts of wax can be used in aqueous inkjet ink compositions. However, generally, the amount is selected such that the total solids content of the aqueous inkjet ink composition is 5% to 15% by weight, 6% to 12% by weight, or 7% to 10% by weight. (where weight % is (total weight of solids) / (total weight of aqueous inkjet ink composition)) * (It refers to 100.)

[0061] surfactant

[0062] Aqueous inkjet ink compositions 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, mireth sulfate, and sodium dioctyl sulfosuccinate series), nonionic surfactants (Surfynol® 104 series, Surfynol® 400 series, Dynol® 604, Dynol® 607, Dynol® 810, EnviroGem® 360, secondary alcohol ethoxylate series, e.g., Tergitol® 15-S-7, Tergitol® 15-S-9, TMN-6, TMN-100x, and Tergitol® NP-9, Triton® X-100, etc.), and cationic surfactants (Chemguard S-106A, Chemguard Examples include S-208M and Chemguard S-216M. Several fluorinated or silicone surfactants can be used, such as PolyFox™ TMPF-136A, 156A, 151N, Chemguard S-761p, S-764p, Silsurf™ A008, Siltec™ C-408, BYK 345, 346, 347, 348, and 349, and polyethersiloxane copolymer TEGO™ Wet-260, 270, and 500. Several amphoteric fluorinated surfactants, such as alkylbetaine fluorosurfactants or alkylamine oxide fluorosurfactants, such as Chemguard S-500 and Chemguard S-111, can also be used. Other surfactants that may be used include Surfynol PSA 336, Surfynol SE-F, and Surfynol 107L.

[0063] Various amounts of surfactant can be used in aqueous inkjet ink compositions. In embodiments, the surfactant is present in an amount ranging from 0.01% to 2% by weight. (where weight % is (total weight of surfactant) / (total weight of aqueous inkjet ink composition)) * (This refers to 100.) When two or more types of surfactants are used, these amounts refer to the total amount of surfactants.

[0064] additives

[0065] Various additives can be used in aqueous inkjet ink compositions to adjust their properties. Suitable additives include biocides; fungicides; stabilizers; pH adjusters such as acids or bases, phosphates, carboxylates, sulfites, amine salts, and buffers; metal ion sequestering agents such as EDTA (ethylenediamine tetraacetic acid); anti-foaming agents; defoaming agents; and wetting agents.

[0066] Various amounts of additives can be used in aqueous inkjet ink compositions. In embodiments, additives are present in amounts ranging from 0.01% to 5% by weight (where weight % is (total weight of additives) / (total weight of aqueous inkjet ink composition)). * (This refers to 100.) If two or more additives are used, these amounts refer to the total amount of additives.

[0067] In at least one embodiment, the aqueous inkjet ink composition is free of (i.e., does not contain) a coagulant, a flocculant, and a plasticizer. In the embodiment, the aqueous inkjet ink composition is free of (i.e., does not contain) any pyrrolidone solvent such as N-methylpyrrolidone, and is free of (i.e., does not contain) Texanol and Texanol isobutyrate. In the embodiment, 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 these resin particles do not require the addition of additives to further adjust viscosity. This means that the aqueous inkjet ink composition may not contain (i.e., does not include) water-soluble resins or emulsions, aqueous binders, polymer dispersants, or combinations thereof. This includes the possibility of excluding any of the water-soluble resins or emulsions, aqueous binders, or polymer dispersants described below. However, it is understood that in some embodiments, such compounds may be included. Finally, it should be noted that the terms water-soluble resin, water-soluble emulsion, aqueous binder, and polymer dispersant do not encompass the resin particles themselves. Exemplary water-soluble resins / emulsions are polyethylene glycol and polyvinylpyrrolidone.

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

[0070] Exemplary polymer dispersants include acrylic polymers such as styrene-acrylic copolymers, vinylpyrrolidone copolymers, urethane or polyurethane dispersions, and acrylic-urethane hybrid dispersions. More specific polymer 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 incorporated by reference for dispersant purposes, and those described in U.S. Patent Application No. 2019284414 incorporated by reference for dispersant purposes.

[0071] Similarly, an aqueous inkjet ink composition may not contain (i.e., does not include) any resin other than that provided by the resin particles. This includes not containing polyurethane, poly(meth)acrylate (other than the resin particles themselves), polyester, or any combination thereof. A single type of resin may be used. Similarly, an aqueous inkjet ink composition itself is generally not curable and therefore does not contain (i.e., does not contain) an initiator. It should be noted that any other exclusions referenced above with respect to resin particles and latex may apply to embodiments of the aqueous inkjet ink composition.

[0072] In some 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 waxes and additives. In some embodiments, the ink composition comprises (or consists of) a solvent system, resin particles, a colorant, a wax, and optionally an additive. In any of these embodiments, the additive may be selected from stabilizers, surfactants, anti-foaming agents, defoamers, wetting agents, and biocides. In any of these embodiments, the components may be selected from the solvent system, resin particles, colorants, waxes, and additives disclosed herein. In any of these embodiments, the amounts of the 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 desired components in desired amounts. An exemplary method includes adding one of the disclosed latex (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 an aqueous inkjet ink composition. A third mixture containing wax may be added to the combined first and second mixtures. Mixing and / or heating may be used in the method. The aqueous inkjet ink composition may be filtered before use. Exemplary details are provided in the following examples.

[0074] characteristics

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

[0076] Aqueous inkjet ink compositions may be characterized by their water resistance. Wet abrasion resistance, measured as described in the following examples, provides a measure of water resistance. In the examples, the aqueous inkjet ink compositions exhibit a wet abrasion resistance of at least 10, 15, or 20 when measured using a droplet of about 4.5 ng of ink, or at least 20, 25, or 30 when measured using a droplet of about 9 ng of ink. In addition, generally high T g The value is associated with insufficient wet abrasion resistance, therefore, the relatively high T of the exemplary resin particles. g Considering the values ​​(80°C and 67°C), this result is surprising.

[0077] Aqueous inkjet ink compositions may be characterized by their open-air stability. Such stability is measured by observing the time it takes for an aqueous inkjet ink composition to gel upon contact with air. This time may be measured as described in the following examples. In the examples, the time to gel is in the range of more than 2 hours, more than 3 hours, more than 4 hours, or 3 to 5 hours. As shown in the examples, the time to gel in the exemplary aqueous inkjet ink composition was extended by approximately 100% compared to a comparative aqueous inkjet ink composition containing resin particles formed from a hydrophilic monomer (hydroxyethyl acrylate) instead of dioxane / dioxolane monomer, 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 stability in open air compared to resin particles based on amphiphilic dioxane / dioxolane monomer.

[0078] Aqueous inkjet ink compositions may be used to form printed images. 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 nozzle is selectively heated in an image pattern, thereby ejecting droplets of the ink composition in an image pattern. Alternatively, the printing apparatus may use an acoustic inkjet process, in which droplets of the ink composition are ejected in an image 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 an image pattern by vibration of a piezoelectric vibrating element. Any suitable substrate may be used.

[0079] The method may include: injecting ink droplets in an image pattern onto an intermediate transfer member; heating the image to partially or completely remove the solvent; and transferring the ink composition in an image pattern from the intermediate transfer member to a final recording substrate. The intermediate transfer member may be heated to a temperature higher than the temperature of the final recording sheet but lower than the temperature of the ink composition in the printing apparatus. Offset or indirect printing processes are also disclosed, for example, in U.S. Patent No. 5,389,958, the disclosure of which is fully incorporated herein by reference.

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

[0081] The use of these latex / resin particles is not limited to providing ink compositions. For example, considering the adhesive properties of the resin particles described above, latex may 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 may be formed by coating any desired amount of any of the latex described herein onto a substrate, and then removing water from the deposited latex to form a layer. Various thin-film deposition techniques may be used to coat the latex. Any desired substrate, e.g., paper, polymer, etc., may be used. A second substrate may be applied on top of the layer to form a bonded article, i.e., two substrates bonded to each other via an adhesive between the substrates. Any of the additives disclosed above with respect to ink compositions may be included in the latex to achieve the desired properties of the adhesive. Useful additives may include surfactants, wetting agents, and viscosity modifying additives. Any of these additives described above may be used in the amounts described above. Other additives that may be used include tackifiers such as rosin esters, rosin acids, and combinations thereof. Any exclusions described above with respect to latex and ink compositions may also apply to embodiments of adhesives. A latex comprising water, resin particles, and optionally additives, configured to provide an adhesive, may be referred to as an aqueous adhesive composition. [Examples]

[0082] The following examples are provided to further define the various types of this disclosure. These examples are for illustrative purposes only and are not intended to limit the scope of this disclosure. Unless otherwise stated, proportions and percentages are given by weight. As used herein, “room temperature” refers to a temperature of about 20°C to about 25°C. Examples 1-3

[0083] A reactive surfactant solution was prepared by mixing 1.1 grams of Montello Hitenol AR 1025 with 35 grams of deionized water in a glass reactor. The reaction mixture 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 75°C and maintained 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, monomer emulsions were 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 emulsions. Different amounts of these components were used in each of Examples 1-3, as shown in Table 1. The emulsified mixtures were slowly supplied to the reactor for 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 formulations are shown in Table 1, and their properties are shown in Table 2. Using Malvern Nano-ZS, D- (z、ave)、 D (v、50) (D 50 The dimensions and polydispersity index (PDI) of latex resin particles, including those in the T, were analyzed. g The temperature was measured using a TA Instruments Discovery DSC 2500 at a rate of 10°C / min in three consecutive cycles of heating-cooling-heating. g The value is related to the latex resin particles. Example 4

[0086] In Example 4, the monomer emulsion from Example 2 was used in a different polymerization process. Specifically, latex was prepared using seed emulsion polymerization. Once the monomer emulsion from Example 2 was prepared, 25% by weight of the monomer emulsion was supplied to a glass reactor at a rate of 0.5 mL / min. Next, 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 polymerization. This polymerization was allowed to proceed for 30 minutes. Then, the remaining emulsion was supplied to the reactor over 1.5 hours, and the reaction was continued for 2 hours. Next, an additional 0.15 g of APS dissolved in DI water was added to the reactor over 10 minutes, and the reaction was continued 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 formulations are shown in Table 1, and their properties are shown in Table 2. Example 5 (Comparison)

[0087] In Example 5, the procedure of Example 1 was repeated, but 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 its properties are shown in Table 2. Example 6 (Comparison)

[0088] In Example 6, the procedure of Example 1 was repeated, but hydrophilic hydroxyethyl acrylate was used instead of the amphiphilic dioxane / dioxolane monomer. 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 its properties are shown in Table 2. Example 7 (Comparison)

[0089] In Example 7, the procedure of Example 1 was repeated, but dioxane / dioxolane monomer and hydroxyethyl acrylate were not used. The latex formulation is shown in Table 1, and the latex properties are shown in Table 2.

[0090] [Table 1]

[0091] [Table 2] Examples 8-15

[0092] Aqueous inkjet ink compositions were formed using the latex of Examples 1, 2, 3, and Comparative Example 5. Another comparative aqueous inkjet ink composition was formed using a water-soluble resin without using resin particles. The aqueous inkjet ink compositions were formed using the following steps, and their formulations are shown in Table 3.

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

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

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

[0096] 4. Mixture B was slowly added to mixture A. Once the addition was complete, the components were mixed for a further 20 minutes.

[0097] 5. Add the wax and continue mixing for another 15 minutes.

[0098] 6. After mixing, the aqueous inkjet ink composition was left at room temperature for approximately 60 minutes, and then its pH, conductivity, and surface tension were checked.

[0099] [Table 3]

[0100] Inkjet ink compositions were sprayed onto different paper substrates, including Kodak photo paper, McCoy® Gloss #100, and Xerox® Bold, using a Dimatix DMP2800 printer. The first set of key test parameters used was as follows: droplet mass = 4.5–4.8 ng (i.e., approximately 4.5 ng), droplet velocity = 6–7 m / sec, 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: droplet mass = 8.5–9 ng (i.e., approximately 9 ng), droplet velocity = 9–11 m / sec, frequency = 5 kHz, voltage = 24–27 V, and print temperature = 20°C–40°C. The print parameter was 600 × 600 dpi. Measurements were performed using a PIAS II instrument, a personal image analysis system with a digital magnifying glass. To measure dot size and diameter, a high-resolution optical module with a field of view of approximately 3.2 mm × 2.4 mm and approximately 5 μm / pixel was used. The results are shown in Table 4. The aqueous inkjet ink compositions prepared using the latex of Examples 1-3 passed continuous spraying for >10-30 minutes with clean faceplates and no nozzle clogging. The ink droplets also maintained their spherical and circular shapes.

[0101] The stability of aqueous inkjet ink compositions in open air was investigated by visually evaluating the initiation of structure formation, the gelation state, and the fully gelled ink. For each investigation, 4 grams of test ink, along with a control ink, were dispensed into identical Pyrex Petri dishes (60 mm diameter, 10 mm height) in a laboratory environment (32% relative humidity, 22°C) and inspected every 30 minutes over the entire 5-hour test period. At each inspection interval, the ink dishes were gently rotated to assess the rigor of structure formation.

[0102] Water-based inkjet ink compositions were tested for wet abrasion resistance (20 double rubs using a wet Q-tip) (water resistance). A thin layer (wire-wound rod RDS2.5) of each inkjet ink composition was coated onto McCoy Gloss #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 the ink was observed.

[0103] To determine the gloss difference value, gloss measurements were obtained for aqueous inkjet ink compositions. A BYK Gardner Micro Gloss meter (75°) was used to measure gloss on coated paper substrates. Once the ink was printed on the paper substrate, the print was held for 24 hours. Gloss at 75° was measured with a digital micro gloss meter. The print was then wiped 30 times, and the gloss was measured again. The gloss difference before and after the 30 wipes was calculated. A lower gloss difference indicates better print fastness against friction.

[0104] [Table 4]

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

[0106] In particular, the latex / resin particles of Examples 1-4 showed pH responsiveness. For example, the latex resin particles of Example 3 showed D as the pH increased from 3 to 8. 50The particle size showed a 25% increase. Similarly, the latex in Example 3 showed an almost 5-fold increase in viscosity. A tuning fork vibratory viscometer (Cole-Parmer) was used to measure viscosity. At 40% solids content, room temperature, and pH 3, the viscosity was 37 cP, and at 34.4% solids content, 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 (prepared using the latex / resin particles of Examples 1-3) exhibited excellent print performance, showing improved spray (>30 minutes, no misdirection or satellite spray), waiting time, and decapping time. More specifically, the printed images of the aqueous inkjet ink compositions of Examples 10 and 11 (prepared using the latex / resin particles of Example 2) showed good circularity and line definition, and the solid blocks showed surface coverage similar to or better than that of Comparative Examples 13-15.

[0108] In addition, the use of dioxane / dioxolane monomer dramatically improved the mechanical properties of the printing ink, as evidenced by increased water resistance (wet abrasion resistance) and reduced gloss difference. (See Table 4.) This is due to the T of the resin particles in Examples 9 and 11. g The high T g The values ​​are typically associated with insufficient wet abrasion resistance and a high gloss difference, as in the case of Comparative Example 14.

[0109] Finally, the use of dioxane / dioxolane monomers significantly improved the open-air stability of the aqueous inkjet ink compositions. Examples 8-12 of the aqueous inkjet ink compositions (prepared from the latex / resin particles of Examples 1-3) showed extended flow times and delayed initiation of structure formation (gelation) when exposed to open airflow. Specifically, they showed an improvement of at least 1-2 hours in the initiation and progression of gelation. This represents an improvement of more than 100% compared to 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 (PEG4000). These components were expected to suppress gelation compared to the amphiphilic dioxane / dioxolane monomers of Examples 8-12.

[0110] The term “exemplary” is used herein to mean an example, case, or representation. Any embodiment or design described herein as “exemplary” is not necessarily construed as being preferable or advantageous to other embodiments or designs. Furthermore, for the purposes of this disclosure, unless otherwise specified, “a” or “an” means “one or more.”

[0111] Where not already included, all numerical values ​​of parameters in this disclosure are referred to by the term “approximately,” meaning approximate. This includes variations inherent in the measurement of the relevant parameters as understood by those skilled in the art. This also includes the exact values ​​of the disclosed numerical values ​​and the rounded values ​​of the disclosed numerical values.

[0112] The foregoing description of exemplary embodiments of the Disclosure is provided for illustrative and explanatory purposes only. It is not intended to be exhaustive or to limit the Disclosure to the exact form disclosed, and modifications and variations are possible in light of the above teachings or may be obtained from practices of the Disclosure. Embodiments are selected and described in order to illustrate the principles of the Disclosure and to enable those skilled in the art to utilize the Disclosure in various embodiments as a practical application of the Disclosure, and with various modifications suitable for the particular intended use. The scope of the Disclosure is intended to be defined by the claims and equivalents thereof appended herein. Another aspect of the present invention may be as follows: [1] An ink composition comprising water, resin particles, a colorant, and optionally a wax, wherein the resin particles comprise a polymerization product of a reaction 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 portion, an ester of (meth)acrylic acid and an alcohol containing a dioxane portion, or both thereof. [2] The ink composition according to [1], wherein the alcohol containing the dioxane portion or the alcohol containing the dioxalane portion is a triol acetal, a triol ketal, or a triol carbonate. [3] The ink composition according to [2], wherein the triol is glycerol or trimethylolpropane. [4] The dioxane / dioxalane monomer has formula I or formula II, [ka] The ink composition according to [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, carbonyl oxygen, alkyl group, aryl group, and alkoxy group. [5] The ink composition according to [1], wherein the dioxane / dioxalane 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 [1], wherein the dioxane / dioxalane monomer is glycerol formal (meth)acrylate. [7] The resin particles have a pH that depends on the pH of the latex containing water and the resin particles. 50 The ink composition according to [1], having particle size. [8] The above D at a pH of approximately 8 50 The particle size is such that the pH is approximately 3. 50 The ink composition described in [7] above, which is larger than the particle size. [9] The above D at a pH of approximately 8 50 The ink composition according to [8], wherein the particle size is at least about 15% larger.

[10] The resin particles are approximately 90 nm or smaller and have a pH of approximately 3. 50 The ink composition according to [1], having particle size.

[11] The ink composition according to [1], wherein the water is present in an amount of at least about 50% by weight.

[12] The ink composition according to [1], wherein the ink composition does not contain silica particles, a water-soluble resin or emulsion thereof, an aqueous binder, a polymer dispersant, or a combination thereof.

[13] The ink composition according to [1], which exhibits a gloss difference of less than about 5 units, a wet abrasion resistance of at least about 10 when measured using about 4.5 ng of the ink composition, or both.

[14] The ink composition according to [1], which indicates a time to gelation upon exposure to air of at least about 2 hours.

[15] The ink composition according to [1], wherein the ink composition is an aqueous inkjet ink composition.

[16] The ink composition according to [1], wherein the additional monomer is an alkyl (meth)acrylate present in the resin particles in an amount of at least about 15% by weight.

[17] The ink composition according to

[16] , wherein the additional monomer is butyl (meth)acrylate.

[18] The ink composition according to [1], wherein the additional monomer is an acidic monomer.

[19] The ink composition according to

[18] , wherein the reactant comprises two different types of the acidic monomer.

[20] The ink composition according to [1], wherein the reactant further comprises styrene, alkyl (meth)acrylate, acidic monomer, and reactant surfactant, one of which is the additional monomer.

Claims

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

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

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

4. The dioxane / dioxolane monomer has formula I or formula II, 【Chemistry 1】 The ink composition according to claim 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, carbonyl oxygen, alkyl group, aryl group, and alkoxy group.

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 depend on the pH of the latex containing water and the resin particles. 50 The ink composition according to claim 1, having particle size.

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

9. The ink composition according to claim 1, wherein the ink composition does not contain silica particles, a water-soluble resin or emulsion thereof, an aqueous binder, a polymer dispersant, or a combination thereof.

10. The ink composition according to claim 1, which exhibits a gloss difference of less than 5 units, a wet abrasion resistance of at least 10 when measured using 4.5 ng of the ink composition.

11. The ink composition according to claim 1, which indicates a time until gelation occurs upon exposure to air of at least two hours.

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, acidic monomer, and reactive surfactant, one of which is the additional monomer.

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