Latex composition having pH-responsive resin particles

Abstract

The present invention provides a latex that can include water and resin particles, the resin particles comprising the polymerization product of reactants including a dioxane / dioxolane monomer and an additional monomer, wherein 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.

Description

Background Art

[0001] Latexes for aqueous inkjet ink compositions are 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 resin particles of the latex act as a binder, which helps form a water-impermeable polymer film that protects the printed image. To adjust the viscosity of the aqueous inkjet ink composition, water-soluble resins are often added to the ink composition. However, water-soluble resins can induce flocculation and aggregation of the resin particles and interfere with their electrostatic stability. Water-soluble resins also reduce the water fastness of images printed from the aqueous inkjet ink composition. Summary of the Invention

[0002] The present disclosure provides a 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 of the present invention exhibit pH responsiveness for providing improved latexes and related compositions. For example, the size of the embodiments of the resin particles depends on pH, including exhibiting a larger size at higher pH values. The viscosity of the latex containing such resin particles is also pH dependent, including exhibiting a larger viscosity at higher pH values. This feature allows the synthesis of resin particles at low pH values and low viscosities. Then, a relatively low amount of resin particles can be used to prepare an ink composition at a higher pH value at a desired viscosity. In addition, although they can be used, viscosity adjustment does not require water-soluble resins or silica additives. In view of this unique pH responsiveness, in the present disclosure, embodiments of the resin particles, latex and related compositions may be referred to as "pH responsive". The ink composition containing the embodiments of the resin particles also exhibits extended open air stability, thereby facilitating the collection of waste ink from the open air waste tray of an aqueous inkjet system. Finally, the embodiments of the resin particles also exhibit a relatively high glass transition temperature (T g ). Despite high T g High T values are desirable for stability, scratch resistance, reduced tack, and offset transfer, but such properties are also known to negatively impact gloss differential and adhesion. Surprisingly, ink compositions comprising embodiments of high Tx resin particles exhibit low gloss differential and high adhesion, including excellent waterfastness.

[0003] In an embodiment, a latex is provided that comprises water and resin particles comprising the polymerization product of reactants including a dioxane / dioxolane monomer and an additional monomer, wherein 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.

[0004] In other embodiments, an adhesive is provided that includes a layer of resin particles located on a surface of a substrate, the resin particles comprising the polymerization product of reactants including a dioxane / dioxolane monomer and an additional monomer, wherein 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.

[0005] Other principal features and advantages of the present disclosure will become apparent to those skilled in the art after reviewing the following drawings, detailed description, and appended claims. DETAILED DESCRIPTION

[0006] latex

[0007] In one aspect, latex is provided. Such latex comprises resin particles synthesized by various monomers, thereby forming the polymer material constituting the resin particles. Using at least one type of monomer, the monomer is an ester of (meth) acrylic acid and an alcohol comprising a dioxane moiety or an alcohol comprising a dioxolane moiety. (As used in, for example, "(meth) acrylic acid" refers to both acrylic acid and methacrylic acid.) In the present disclosure, this type of monomer can be referred to as a "dioxane / dioxolane monomer". The phrase dioxane / dioxolane monomer encompasses monomers as esters of (meth) acrylic acid and an alcohol comprising a dioxane moiety, monomers as esters of (meth) acrylic acid and an alcohol comprising a dioxolane moiety, and these two monomers. The dioxane moiety can be a 1,3-dioxane moiety, and the dioxolane moiety can be a 1,3-dioxolane moiety. The alcohol comprising 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 carbon or hydrogen are replaced with bonds to non-hydrogen and non-carbon atoms. The dioxane / dioxolane monomer may have Formula I (dioxane) or II (dioxolane) as shown below, wherein R is selected from hydrogen and methyl; R' is selected from hydrogen and ethyl; and Z is selected from hydrogen, oxygen of a carbonyl group, an alkyl group, an aryl group, and an alkoxy group. Either or both types of monomers may be used in the resin particles.

[0008]

[0009] A carbonyl group refers to a C=O group, i.e., Z is an O covalently bonded to a carbon via a double bond, thereby forming a carbonyl group between the two oxygens of a 5- or 6-membered ring. An alkyl group may be straight or branched. An alkyl group may have 1 to 20 carbons. This includes having 1 to 18 carbons and 1 to 10 carbons, such as 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 carbons. An alkyl group may be substituted or unsubstituted. An aryl group may be a monocyclic ring with an aromatic ring, such as benzene, or a polycyclic ring with one or more fused rings. An aryl group may be unsubstituted or substituted as described above for an alkyl group, although substituted aryl groups also encompass aryl groups in which the bond to hydrogen is replaced by a bond to an unsubstituted or substituted alkyl group as described above. An alkoxy group refers to an -O-alkyl group.

[0010] Exemplary dioxane / dioxolane monomers include glycerol formal (meth) acrylate, trimethylolpropane formal (meth) acrylate, and isopropyl glycerol (meth) acrylate. A single type of dioxane / dioxolane monomer 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" (and the names of other dioxane / dioxolane monomers described in this paragraph) refers to the dioxane isomer, the dioxolane isomer, or both. That is, the name encompasses all possibilities.

[0011] At least 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.

[0012] Typically, additional monomers are used to form the 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 (β-CEA), phenyl acrylate, methyl α-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-vinyl indole; N-vinyl pyrrolidone; methacrylate; acrylamide; methacrylamide; vinyl pyridine; vinyl pyrrolidone; vinyl-N-methyl pyridinium chloride; vinyl naphthalene; p-chlorostyrene; vinyl chloride; vinyl bromide; vinyl fluoride; ethylene; propylene; butylene; and isobutylene. Combinations of different types of these monomers can be used. In an embodiment, the monomers used to form the resin particles include styrene, (meth) alkyl acrylates (e.g., methyl (meth) acrylate, ethyl (meth) acrylate), butyl (meth) acrylate or a combination thereof. Therefore, the alkyl group of the (meth) alkyl acrylate may have 1 or more carbons, 2 or more carbons, 4 or more carbons or 1 to 6 carbons.

[0013] Acidic monomers can 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, dimethacrylic acid, maleic anhydride, maleic acid, styrenesulfonic acid, vinylsulfonate, cyanoacrylic acid, vinylacetic acid, allylacetic acid, ethylideneacetic acid, propylideneacetic acid, crotonic acid, fumaric acid, itaconic acid, sorbic acid, angelic acid, cinnamic acid, styrylacrylate, citraconic acid, glutaconic acid, aconitic acid, phenylacrylate, acryloxypropionic acid, aconitic acid, phenylacrylate, acryloxypropionic acid, vinylbenzoic acid, N-vinylsuccinamic acid, mesaconic acid, methyl The present invention also includes acryloyl alanine, acryloyl hydroxyglycine, sulfoethyl methacrylic acid, sulfopropyl acrylic acid, styrenesulfonic acid, sulfoethyl acrylic acid, 2-methacryloyloxymethane-1-sulfonic acid, 3-methacryloyloxypropane-1-sulfonic acid, 3-(vinyloxy)propane-1-sulfonic acid, ethylenesulfonic acid, vinylsulfuric acid, 4-vinylphenylsulfuric acid, ethylenephosphonic acid, vinylphosphonic acid, vinylbenzoic acid, 2-acrylamido-2-methyl-1-propanesulfonic acid and combinations thereof. These acidic monomers also encompass salts thereof, such as salts of sulfonic acids.

[0014] In embodiments, two different acidic monomers are used to form the resin particles, each having a different pK a The pK values of two different acidic monomers are 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, two different acidic monomers are present in the monomer emulsion used to form the resin particles, wherein the monomer having the higher pK a Acidic monomers with lower pK a The weight ratio of the acidic monomers is in the range of 0.1 to 10. This includes 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, the acidic monomers including methacrylic acid and sulfonic acid.

[0015] Multifunctional monomers can be used to form resin particles, i.e., those containing more than one polymerizable group (e.g., 2, 3, 4). 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, for example, poly(ethylene glycol) diacrylate having a molecular weight of 250 g / mol. Other poly(ethylene glycol) di(meth)acrylates can be used, including those having a molecular weight in the range of 214 g / mol to 1000 g / mol, 214 g / mol to 500 g / mol, and 214 g / mol to 300 g / mol. The values of these molecular weights can be determined using gel permeation chromatography. Other difunctional monomers include diacrylate compounds bonded to an alkyl chain containing an ether bond, such as diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol #400 diacrylate, polyethylene glycol #600 diacrylate, dipropylene glycol diacrylate, and compounds obtained by substituting methacrylate for acrylates of these compounds; and diacrylate compounds bonded to a chain containing an aromatic group and an ether bond, such as polyoxyethylene (2)-2,2-bis(4-hydroxyphenyl)propane diacrylate, polyoxyethylene (4)-2,2-bis(4-hydroxyphenyl)propane diacrylate, and compounds obtained by substituting methacrylate for acrylates 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 to an alkyl chain such as ethylene glycol diacrylate, 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, 1,10-dodecanediol diacrylate, neopentyl glycol diacrylate, and compounds obtained by substituting methacrylate for the acrylates of these compounds. Polyfunctional monomers include pentaerythritol triacrylate, trimethylolmethane triacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, oligoester acrylates, and compounds obtained by substituting methacrylate for the acrylates of these compounds.

[0016] Reactive surfactants can be used to form the resin particles. Suitable reactive surfactants contain polymerizable (and therefore reactive) groups so that they are incorporated into the 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 alkylphenyl ether ammonium sulfate, Hitenol BC-10, BC-20, BC10-25, BC-2020, BC-30; polyoxyethylene styrenated phenyl ether ammonium sulfate, including Hitenol AR-10, AR-20, AR-2020; nonionic polyoxyethylene alkylphenyl ether, 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.

[0017] Chain transfer agents can be used to form resin particles. The chain transfer agent can be a mercaptan (mercaptan or thiol). Suitable chain transfer agents include n-dodecyl mercaptan (NDM), n-dodecyl mercaptan (DDT), tert-dodecyl mercaptan, 1-butyl mercaptan, 2-butyl mercaptan, octanol and their combinations. Halogenated carbons (such as carbon tetrabromide, carbon tetrachloride and their combinations) can be used as chain transfer agents.

[0018] In embodiments, certain monomers may be excluded from forming the resin particles. The excluded monomers may include one or more of the following: vinyl imidazolium monomers, urethane (meth)acrylate monomers, and silyl ester monomers, such as triisopropylsilyl (meth)acrylate.

[0019] In forming a latex containing resin particles, various combinations of the above monomers can be used in a monomer emulsion containing a solvent. Water is typically 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 values that achieve the properties described below. Exemplary amounts are provided below.

[0020] Dioxane / dioxolane monomers can be used in monomer emulsions 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 % refers to (the total weight of dioxane / dioxolane monomers) / (the total weight of monomers excluding reactive surfactants in the monomer emulsion)*100). Acidic monomers can be used in monomer emulsions in amounts ranging from 2 wt % to 20 wt % and 5 wt % to 15 wt %. (The meaning of wt % is similar to that described for dioxane / dioxolane monomers.) As described above, two different types of acidic monomers with different pKa values can be used in the above-mentioned weight ratio. Multifunctional monomers (including difunctional monomers) can be used in monomer emulsions in amounts ranging from 0.001 wt % to 1 wt %, 0.001 wt % to 0.8 wt % and 0.01 wt % to 0.6 wt %. (The meaning of weight percent is similar to that described for the dioxane / dioxolane monomers.) Other monomers (e.g., styrene, alkyl (meth)acrylates) may be present in amounts ranging from 70 to 97 weight percent and from 75 to 90 weight percent. (The meaning of weight percent is similar to that 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 an amount of at least 15 weight percent, at least 20 weight percent, or in an amount ranging from 15 to 30 weight percent.

[0021] The reactive surfactant can be used in the monomer emulsion in an amount ranging from 1.5 wt% to 6.5 wt%. (Here, wt% refers to (total weight of reactive surfactant) / (total weight of monomers in the monomer emulsion, including the reactive surfactant monomer)*100). This range includes 1.5 wt% to 5 wt%.

[0022] Chain transfer agents may be present in the monomer emulsion and may be used in various suitable amounts (e.g., 0.25 wt % to 2.5 wt %). (Here, wt % refers to (total weight of chain transfer agent) / (total weight of monomers in the monomer emulsion excluding reactive surfactants)*100.)

[0023] 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 are included, i.e., a relatively high T g monomers (e.g., styrene or methyl methacrylate) and relatively low T gMonomer (e.g., alkyl acrylate, such as butyl acrylate). In an embodiment, a multifunctional monomer is included. In an embodiment, 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) (or consists of them). In any of these embodiments, a chain transfer agent can be used. In any of these embodiments, the amounts of various monomers, reactive surfactants, and chain transfer agents can be used as described above. The remainder can be composed of solvent.

[0024] In an embodiment, the monomer emulsion is free of (i.e., does not include) a surfactant. However, in other embodiments, a surfactant may be used. Here, "surfactant" refers to a non-reactive, non-polymerizable anionic surfactant such as sodium dodecyl sulfate (SDS), sodium dodecylbenzenesulfonate, sodium dodecylnaphthalene sulfate; dialkylbenzene alkyl sulfates; palmitic acid; alkyldiphenyl oxide disulfonates; and branched sodium dodecylbenzenesulfonate. "Surfactant" also refers to a non-reactive, non-polymerizable cationic surfactant such as alkylbenzyldimethylammonium chloride, dialkylbenzenealkylammonium chloride, lauryltrimethylammonium chloride, alkylbenzylmethylammonium chloride, alkylbenzyldimethylammonium bromide, benzalkonium chloride, cetylpyridinium bromide, trimethylammonium bromide, halide salts of quaternized polyoxyethylenealkylamines, and dodecylbenzylammonium chloride. "Surfactant" also refers to non-reactive, non-polymerizable nonionic surfactants such as polyoxyethylene cetyl ether, polyoxyethylene lauryl ether, polyoxyethylene octyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene oleyl ether, polyoxyethylene sorbitan monolaurate, polyoxyethylene stearyl ether, polyoxyethylene nonylphenyl ether, dialkylphenoxypoly(ethyleneoxy)ethanols, and block copolymers of polyethylene oxide and polypropylene oxide.

[0025] In an embodiment, the monomer emulsion is free of (i.e., does not include) silica particles. Although silica particles have been used to increase viscosity, embodiments of the resin particles of the present invention can provide a latex with high viscosity even in the absence of such silica particles. Commercially available silica particles that may be excluded include 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, P X-30, P t-40, P W-50, CL, and CL-P; and various grades of Nissan Chemical silicas 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.

[0026] Various polymerization techniques can be used to form the resin particles, such as monomer-starved demulsion polymerization, conventional emulsion polymerization, suspension polymerization, miniemulsion polymerization, nanoemulsion polymerization, seeded emulsion polymerization, and microemulsion polymerization. These polymerization techniques can utilize any of the monomer emulsions described above. An exemplary monomer-starved emulsion polymerization process is described below. However, as described above, other processes can be used. (See also Example 4 for a description of an exemplary seeded emulsion polymerization process).

[0027] An exemplary method for preparing a latex containing resin particles includes adding any of the above-mentioned monomer emulsions to a reactive surfactant solution at a feed rate over a period of time. The reactive surfactant solution comprises a solvent and a reactive surfactant. Any of the above-mentioned solvents and any reactive surfactants can be used. The reactive surfactant in the reactive surfactant solution can be of the same type or a different type than the reactive surfactant that may be present in the monomer emulsion. The reactive surfactant solution may further comprise a buffer. Various buffers such as sodium bicarbonate, sodium carbonate, and ammonium hydroxide can be used. The reactive surfactant can be used in an amount ranging from 1 wt % to 10 wt % and from 2 wt % to 5 wt %. (Here, wt % refers to (total weight of reactive surfactant) / (total weight of reactive surfactant solution)*100.) The buffer can be used in an amount ranging from 0.25 wt % to 2.5 wt %. (The meaning of wt % is similar to that described above.)

[0028] The initiator may be included in the reactive surfactant solution. Alternatively, a separate initiator solution comprising the initiator and any of the above-mentioned solvents may be formed and added to the reactive surfactant solution. The separate initiator solution may be added before the monomer emulsion is added. An additional amount 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; and organic soluble initiators including organic peroxides and azo compounds including Vazo peroxides such as VAZO 64. TM , 2-methyl-2-2′-azobispropionitrile, VAZO 88 TM , 2-2′-azobisisobutyramide dehydrate; 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] ] 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-(3,4,5,6-tetrahydropyrimidin-2-yl)propane] dihydrochloride, 2,2′-azobis[2-(5-hydroxy-3,4,5,6-tetrahydropyrimidin-2-yl)propane] dihydrochloride, 2,2′-azo{2-[1-(2-hydroxyethyl)-2-imidazolin-2-yl]propane} dihydrochloride and combinations thereof, etc. The initiator can be used in an amount ranging from 0.05 wt% to 2.5 wt%. (Here, wt% refers to (total weight of initiator) / (total weight of reactive surfactant solution)*100.)

[0029] In embodiments, the reactive surfactant solution comprises a solvent (e.g., water), a reactive surfactant, and optionally one or more of an initiator and a buffer (or consisting of them). In any of these embodiments, the amounts of reactive surfactant, initiator, and buffer can be used as described above. The remainder can be composed of a solvent. At least in some embodiments, the reactive surfactant solution does not contain (i.e., does not include) any of the above-mentioned surfactants. In at least some embodiments, the reactive surfactant solution does not contain (i.e., does not include) any of the above-mentioned silica particles. Therefore, the resin particles can be characterized as not containing (i.e., does not include) any of the above-mentioned surfactants and / or any silica particles. In at least some embodiments, the reactive surfactant solution does not contain (i.e., does not include) any monomer except the reactive surfactant monomer present in the solution.

[0030] 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., a temperature greater than room temperature, such as in the range of 50° C. to 90° C.). This can be accomplished by purging and heating the reactive surfactant solution with an inert gas prior to the addition of the monomer emulsion and continuing during the addition of the monomer emulsion.

[0031] 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 of the monomer emulsion undergo a polymerization reaction to form resin particles of a high-viscosity latex. The feed rate is slow enough so that the polymerization is carried out under "monomer-deficient" conditions. This means that the feed rate is no greater than the rate of polymerization between, for example, styrene and acrylate monomers. Exemplary feed rates include those in the range of 1 mL / min to 10 mL / min based on a total reaction volume of 1 L. Exemplary time periods include those in the range of 60 minutes to 600 minutes. After the monomer emulsion has been added, the polymerization can be continued for an additional period of time with or without the addition of additional initiator. Exemplary additional time periods include those in the range of 1 hour to 18 hours. Both the addition of the monomer emulsion and the polymerization after the addition can be carried out under an inert gas and at elevated temperatures. Optionally, the formed latex can be treated by standard techniques such as coagulation, dissolution and precipitation, filtration, washing, or drying. The treated or untreated latex can be used to form the ink composition described below.

[0032] The monomer-deficient emulsion polymerization process described above does not involve the use of resin seeds in forming the resin particles. However, as described above, seeded emulsion polymerization techniques can be used (see Example 4).

[0033] The method may further include forming a monomer emulsion, forming a reactive surfactant solution, and / or forming an initiator solution. Each may be formed by combining and mixing the desired components in the desired amounts.

[0034] The composition of resin particles depends on the selection of monomer and their relative amount, and the polymerization reaction between the selected monomers producing the polymerized product as described above. Therefore, various compositions are contained, including those compositions of the various polymerized products based on the reactants comprising various monomer combinations. As mentioned above, reactant includes dioxane / dioxolane monomer, but in other aspects, the selection of other monomers is not particularly limited. For the sake of clarity, the composition of resin particles can be identified by reference to the monomer of polymerization, thereby identifying that the chemical form of those monomers is usually changed due to polymerization reaction. In embodiments, resin particles include the polymerized product (for example, copolymer) (or consisting of them) of reactant, and this reactant includes dioxane / dioxolane monomer and other monomer. In embodiments, resin particles include the polymerized product (for example, copolymer) (or consisting of it) of reactant, and this reactant includes dioxane / dioxolane monomer, other monomer and multifunctional monomer. In embodiments, the resin particles comprise (or consist of) the polymerization product (e.g., a copolymer) of reactants including dioxane / dioxolane monomers, 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 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 multifunctional / difunctional monomers. In each of these embodiments, the monomers may be present in the resin particles in the amounts described above. (Experiments have shown that the conversion of the monomers is greater than 99.9%.) For example, the amount of dioxane / dioxolane monomers in the resin particles may range from 1% to 40% by weight. As described above, the % by weight refers to (total weight of dioxane / dioxolane monomers) / (total weight of monomers in the resin particles excluding the reactive surfactant)*100.

[0035] 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 specification, the different chemical moieties resulting from the polymerization reaction are identified by reference to their corresponding monomers in parentheses, and "ran" refers to the random incorporation of the different monomers into the copolymer. This specification contemplates the presence of an initiator (or portion thereof) at the beginning of each copolymer and during crosslinking via multifunctional / difunctional monomers.

[0036] In certain embodiments where monomers are excluded from forming the resin particles, it follows that such monomers do not participate in the polymerization reaction that forms the polymer matrix of the resin particles. Thus, in these embodiments, the composition of the resin particles can be described as being free of (i.e., not comprising) one or more of vinylimidazolium monomers, urethane (meth)acrylate monomers, and silyl ester monomers (such as triisopropylsilyl (meth)acrylate).

[0037] In embodiments, the latex may be described as being free of (i.e., comprising) resins / polymers other than those provided by the resin of the resin particles of the present invention themselves. This includes being free of polyurethanes, polyurethane (meth)acrylates, poly(meth)acrylates (other than the resin particles themselves), polyesters, silyl ester copolymers, silyl (meth)acrylate polymers, or combinations thereof.

[0038] Because the resin / polymer comprising the resin particles has already been polymerized, the latex itself is generally not curable and therefore does not contain (i.e., does not include) an initiator. This does not preclude the presence of small amounts of unreacted initiator or reacted initiator that may be incorporated into the polymer chain. Similarly, the latex may be described as free of (i.e., does not contain monomers).

[0039] In embodiments, the latex may also be described as being free of (ie, not comprising) fungicides / biocides, such as medetomidine.

[0040] The water content of the latex can be at least 40 wt %. This includes at least 50 wt % and at least 60 wt %. These wt % refer to the weight of water compared to the total weight of the latex.

[0041] In embodiments, the resin particles have a core / shell morphology. Seeded emulsion polymerization (see Example 4) can be used to form core / shell resin particles, wherein 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." However, seeded emulsion polymerization can be used to form resin particles in which the seed monomer emulsion and the feed monomer emulsion have the same composition.

[0042] The resin particles may be characterized by their size. The size of the particles may be reported as D 50 Particle size is the diameter at which 50% of the sample (based on volume) consists of particles having a diameter less than the stated value. D can be measured using a Malvern Zetasizer Nano ZS 50 Particle size. To check the light scattering technique and method, a NIST polystyrene nanosphere control sample having a diameter in the range of 20 nm to 200 nm, available from Microspheres-Nanospheres (a Corpuscular company of Microtrac) or a third party supplier (such as ThermoFisher Scientific) can be used. Because the size of at least embodiments of the resin particles is pH dependent, the size can be reported with respect to a specific pH. In embodiments, the resin particles are characterized by a D at pH 8. 50 The particle size is larger than D at pH 3 50 This includes 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 no greater than 100 nm, no greater than 90 nm, no greater than 80 nm, no greater than 70 nm, or within a range of 60 nm to 90 nm.

[0043] Latexes comprising resin particles of the present invention may be characterized by their viscosity. Viscosity values may refer to specific temperatures and specific solids contents and may be measured using a tuning fork vibration viscometer (Cole-Parmer) as described in the Examples below. Similarly, since at least embodiments of the resin particles make the viscosity of the latex dependent on pH, the viscosity may be reported with respect to a specific pH. In embodiments, the latex comprising resin particles is characterized in that the viscosity at room temperature, 30% solids content, and pH 8 is greater than the viscosity at room temperature, 30% solids content, 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 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. These viscosities are all initial viscosities measured within one day of forming the latex.

[0044] The resin particles of the present invention may also be characterized by their T gT can be measured using Differential Scanning Calorimetry (DSC) TA Instruments DSC 2500 as described in the Examples below. g In an embodiment, T g In the range of 50°C to 100°C. This includes the ranges of 50°C to 90°C and 50°C to 80°C.

[0045] Ink composition

[0046] Any of the above-described resin particles / latexes can be used to provide an ink composition. The type of ink composition is not particularly limited. However, ink compositions comprising a large amount of water (e.g., at least 50% by weight) are particularly useful. Exemplary ink compositions include aqueous inkjet ink compositions and fountain pen ink compositions. Exemplary aqueous inkjet ink compositions are described below. However, it should be understood that the present disclosure extends to other types of ink compositions.

[0047] The resin particles may be present in the aqueous inkjet ink composition in an amount ranging from 1 wt % to 10 wt % and from 5 wt % to 10 wt %. (Herein, wt % refers to (total weight of the resin particles) / (total weight of the aqueous inkjet ink composition)*100.) This range includes 5 wt % to 10 wt %. As described below, various other components may be used to form the aqueous inkjet ink composition.

[0048] Solvent system

[0049] The aqueous inkjet ink composition comprises a water-based solvent system. The solvent system can be composed only of water, or can comprise a mixture of water and a water-soluble and / or water-miscible organic solvent. Water-soluble and water-miscible organic solvents can be referred to as co-solvents or heat-retaining agents in this article. Suitable organic solvents of this type include alcohols and alcohol derivatives, including fatty alcohols, aromatic alcohols, glycols, glycol ethers, polyethylene glycol ethers, long-chain alcohols, aliphatic primary alcohols, aliphatic secondary 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, glycerol, 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, ethylene urea, alkyl urea, alkyl thiourea, dialkyl urea and dialkyl thiourea), carboxylic acids and salts thereof (such as 2-methylvaleric acid, 2-ethyl-3-propyl acrylic acid, 2-ethylhexanoic acid, 3-ethoxypropionic acid, etc.), esters, organic sulfides, organic sulfoxides, sulfones (such as sulfolane), carbitol, butyl carbitol, cellosolves, ethers, tripropylene glycol monomethyl ether, ether derivatives, hydroxy ethers, amino alcohols, ketones, N-methylpyrrolidone, 2-pyrrolidone, cyclohexylpyrrolidone, amides, sulfoxides, lactones, polyelectrolytes, methylsulfonylethanol, imidazole, 1,3-dimethyl-2-imidazolidinone, betaine, sugars (such as 1-deoxy-D-galactitol, mannitol, inositol, etc.), substituted and unsubstituted formamides, and substituted and unsubstituted acetamides. Combinations of these organic solvents can be used.

[0050] Suitable water-soluble and / or water-miscible organic solvents include diols of hydrocarbons having a carbon number of 4 to 7. Examples of such diols include 1,2-pentanediol; 1,2-hexanediol; 1,5-pentanediol; 1,6-hexanediol; 3-methyl-1,3-butanediol; 1,2-butanediol and 2,4-pentanediol; 1,7-heptanediol; 3-methyl-1,5-pentanediol; trimethylolpropane; ethylene urea; 1,2,6-hexanetriol; 1,2,3-butanetriol; sorbitol; triethylene glycol; 1,2,4-butanetriol; glycerol; diglycerol; and triethylene glycol.

[0051] In embodiments, the solvent system includes water, a 1,2-alcohol (eg, 1,2-hexanediol), a glycol (eg, propylene glycol), and glycerol.

[0052] In solvent systems comprising water and organic solvents, the weight ratio of water to organic solvent, as well as the types and relative amounts of different organic solvents, can 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 from 90:10 to 51:49. If more than one organic solvent is used, these weight ratios refer to the total amount of organic solvents. When water may be present in latex, colorants, etc., these weight ratios refer to the total amount of water.

[0053] Similarly, various amounts of additives may be used in the aqueous inkjet 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. (Herein, % by weight refers to (total weight of the solvent system) / (total weight of the aqueous inkjet ink composition)*100.) 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. (Herein, % by weight refers to (total weight of water) / (total weight of the aqueous inkjet ink composition)*100.)

[0054] Colorants

[0055] The aqueous inkjet ink composition may contain 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, 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, 194); acid red dyes (Nos. 1, 8, 32, 35, 37, 52, 57, 9 2, 115, 119, 154, 249, 254, 256); acid blue dye (1, 7, 9, 25, 40, 45, 62, 78, 80, 92, 102, 104, 113, 117, 127, 158, 175, 183, 193, 209); acid yellow dye (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, 100, 106, 107, 118, 127, 132, 142, 157); reactive dyes, such as reactive red dyes (Nos. 4, 31, 56, 180), reactive black dyes (No. 31), reactive yellow dyes (No. 37); anthraquinone dyes, monoazo dyes, disazo dyes, phthalocyanine derivatives (including various phthalocyanine sulfonates), aza(18) annulene, formazan copper complexes and triphenodioxazines;

[0056] The example of suitable pigment includes black pigment, cyan pigment, magenta pigment and yellow pigment. Pigment can be organic or inorganic particles. Suitable inorganic pigment includes carbon black. However, other inorganic pigments may be suitable, such as cobalt blue (CoO-Al2O3), chrome yellow (PbCrO4), iron oxide and titanium dioxide (TiO2). Suitable organic pigments include, for example, azo pigments (including diazo pigments and monoazo pigments), polycyclic pigments (for example, 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 (for example, basic dye type chelates and acid dye type chelates), nitro pigments, nitroso pigments and anthranthrone pigments (such as PR168). Representative examples of phthalocyanine blue and phthalocyanine green 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 thioindigos 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 can be commercially available from many sources in the form of powders or filter cakes, including BASF Corporation, Engelhard Corporation, and Sun Chemical Corporation. The example of an operable black pigment includes carbon pigments. The carbon pigment can be almost any commercially available carbon pigment that provides acceptable optical density and printing characteristics. Suitable carbon pigments for use in the systems and methods of the present invention include, but are not limited to, carbon black, graphite, glassy carbon, charcoal, and combinations thereof.Such carbon pigments can be made by a variety of known methods, such as groove, contact, furnace, acetylene, or thermal processes, and are commercially available from suppliers such as Cabot Corporation, Columbian Chemicals Company, Evonik, and EI DuPont de Nemours and Company. Suitable carbon black pigments include, but are not limited to, Cabot pigments such as. 1400, 1300, 1100, 1000, 900, 880, 800, 700, CAB-O- 200, CAB-O- 300, CAB-O- 450, BLACK and Pigments; Columbian pigments, such as 5000 and 3500; Evonik pigments such as Color Black FW200, FW2, FW2V, FW1, FW18, FW5160, FW 5170, Special Black 6, Special Black 5, Special Black 4A, Special Black 4, U. 140U, V and 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).

[0057] The above list of pigments includes unmodified pigment particles, small molecule attached pigment particles, self-dispersed pigment particles, and polymer dispersed pigment particles.

[0058] When forming the aqueous inkjet ink composition, the colorant can be provided as a colorant dispersion comprising the colorant and a solvent (e.g., water). The colorant can be in the form of particles and have an average particle size of 20 nm to 500 nm, 20 nm to 400 nm, or 30 nm to 300 nm.

[0059] Various amounts of colorant can be used in the aqueous inkjet ink composition. However, typically, the amount is selected so that the total solids content of the aqueous inkjet ink composition (typically provided by the resin particles, colorant, and, if present, wax) is from 5% to 15% by weight, from 6% to 12% by weight, or from 7% to 10% by weight. (Here, wt% refers to (total weight of solids) / (total weight of the aqueous inkjet ink composition)*100.)

[0060] wax

[0061] The aqueous inkjet ink composition may include 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., 1000 nm or less, 500 nm or less, or 100 nm or less in diameter) wax emulsions based on carnauba wax and paraffin wax may be used. Waxes from Michelman 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 emulsions 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 an embodiment, the wax is an anionic nanowax emulsion, such as Michem Lube 190.

[0062] Various amounts of wax can be used in the aqueous inkjet ink composition. However, typically, the amount is selected so that the total solids content of the aqueous inkjet ink composition is from 5% to 15%, from 6% to 12%, or from 7% to 10%. (Here, wt% refers to (total weight of solids) / (total weight of the aqueous inkjet ink composition)*100.)

[0063] surfactants

[0064] The aqueous inkjet ink composition may contain one or more surfactants. Examples of suitable surfactants include anionic surfactants (such as sodium lauryl sulfate (SLS), Dextrol OC-40, Strodex PK 90, ammonium lauryl sulfate, potassium lauryl sulfate, sodium myreth sulfate, and the dioctyl sodium sulfosuccinate series), nonionic surfactants ( 104 series, 400 series, Dynol TM 604、Dynol TM 607、Dynol TM 810, 360, secondary alcohol ethoxylate series, such as Tergitol TM 15-S-7, Tergitol TM 15-S-9, TMN-6, TMN-100x and Tergitol TM NP-9, Triton TM X-100, etc.) and cationic surfactants (Chemguard S-106A, Chemguard S-208M, Chemguard S-216M). Some fluorinated or silicone surfactants, such as PolyFox TM TMPF-136A, 156A, 151N, Chemguard S-761p, S-764p, A008, C-408, BYK 345, 346, 347, 348 and 349, polyether siloxane copolymers Wet-260, 270 500, etc. 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.

[0065] Various amounts of surfactant can be used in the aqueous inkjet ink composition. In embodiments, the surfactant can be present in an amount ranging from 0.01 wt % to 2 wt %. (Here, wt % refers to (total weight of surfactants) / (total weight of the aqueous inkjet ink composition)*100.) If more than one type of surfactant is used, these amounts refer to the total amount of surfactants.

[0066] additive

[0067] Various additives can be used in aqueous inkjet ink compositions to adjust their properties. Suitable additives include one or more biocides; fungicides; stabilizers; pH control agents such as acids or bases, phosphates, carboxylates, sulfites, amine salts, buffer solutions; chelating agents such as EDTA (ethylenediaminetetraacetic acid); antifoaming agents; defoaming agents; and wetting agents.

[0068] Various amounts of additives can be used in the aqueous inkjet ink composition. In embodiments, the initiator can be present in an amount ranging from 0.01 wt % to 5 wt %. (Here, wt % refers to (total weight of additives) / (total weight of the aqueous inkjet ink composition)*100.) If more than one type of additive is used, these amounts refer to the total amount of the additives.

[0069] In at least one embodiment, the aqueous inkjet ink composition is free of (i.e., does not include) a coagulant and free of (i.e., does not include) a coalescing agent and free of (i.e., does not include) a plasticizer. In embodiments, the aqueous inkjet ink composition is free of (i.e., does not include) any pyrrolidone-based solvents, such as N-methylpyrrolidone, and free of (i.e., does not include) Texanol and Texanol isobutyrate. In embodiments, the aqueous inkjet ink composition is free of (i.e., does not include) silica particles.

[0070] As mentioned above, the aqueous inkjet ink composition based on the resin particles of the present invention does not need to add additives to further adjust the viscosity. This can mean that the aqueous inkjet ink composition may not contain (i.e., does not include) water-soluble resins or emulsions, water-based binders, polymeric dispersants, and combinations thereof. This includes any water-soluble resins or emulsions, water-based binders, polymeric dispersants that may be excluded from the description below. However, it should be understood that such compounds may be included in some embodiments. Finally, it should be noted that the terms water-soluble resins, water-soluble emulsions, water-based binders, and polymeric dispersants do not encompass the resin particles of the present invention themselves. Exemplary water-soluble resins / emulsions are polyethylene glycol and polyvinyl pyrrolidone.

[0071] Exemplary water-based binders are Rhoplex I-1955, Rhoplex I-2426D, Rhoplex I-62, Rhoplex I-98, 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 available from ISP under the designations 972, PVP K-15, PVP K-30, PVP K-60, PVP K-85, Ganex P-904LC, PVP / VA W-63. Other exemplary water-based binders that may be excluded include those available from Johnson Polymers (BASF), such as Joncryl 537, Joncryl H538, Joncryl H538.

[0072] Exemplary polymeric dispersants are acrylic polymers such as styrene-acrylic copolymers and vinyl pyrrolidone copolymers, urethane or polyurethane dispersions and acrylic-polyurethane hybrid dispersions. More specific polymeric dispersants that may be excluded include those available from Johnson Polymers (BASF), such as 671, 683, 296, 690, Joncryl HPD 296, Joncryl HPD96-E, Joncryl LMV 7085, Joncryl 8082. Other dispersants that may be excluded include those described in European Patent No. 2097265 (incorporated by reference for the purpose of dispersants) and those described in U.S. Patent Application No. 2019284414 (incorporated by reference for the purpose of dispersants).

[0073] Similarly, the aqueous inkjet ink composition may be free of (i.e., not include) resins other than the resin provided by the resin of the resin particles of the present invention. This includes being free of polyurethane, poly(meth)acrylate (except the resin particles themselves), polyester, or combinations thereof. A single type of resin may be used. Similarly, the aqueous inkjet ink composition itself is typically non-curable and therefore free of (i.e., not including) initiators. It should be noted that any other exclusions mentioned above with respect to resin particles and latex may be applicable to embodiments of the aqueous inkjet ink composition.

[0074] In embodiments, an 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 an additive. In embodiments, an 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 a stabilizer, a surfactant, an antifoaming agent, a defoaming agent, a wetting agent, and a biocide. In any of these embodiments, the component 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 the components may be used as described above.

[0075] 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 comprising a solvent system and additives to the first mixture to form the aqueous inkjet ink composition. A third mixture comprising a wax can be added to the combined first and second mixtures. Mixing and / or heating can be used during the method. The aqueous inkjet ink composition can be filtered before use. Illustrative details are provided in the following examples.

[0076] nature

[0077] The aqueous inkjet ink compositions can be characterized by their gloss differential. The gloss differential can be measured as described in the examples below. In embodiments, the aqueous inkjet ink compositions exhibit a gloss differential of less than 5 units, less than 4 units, or in the range of 1 to 5 units. As demonstrated in the examples below, these values are significantly less than the gloss differential obtained from comparative aqueous inkjet ink compositions comprising resin particles formed from a hydrophilic monomer (hydroxyethyl acrylate) in place of a dioxane / dioxolane monomer. Given the relatively high T values of the exemplary resin particles, the gloss differential can be measured as described in the examples below. g values (80°C and 67°C), which is surprising because the high T g Values generally correlate with high gloss differences.

[0078] The aqueous inkjet ink compositions can be characterized by their water fastness. Wet rub resistance, measured as described in the following examples, provides a measure of water fastness. In embodiments, the aqueous inkjet ink compositions exhibit a wet rub resistance of at least 10, 15, or 20 (as measured using an ink droplet of about 4.5 ng) or a wet rub resistance of at least 20, 25, or 30 (as measured using an ink droplet of about 9 ng). Similarly, given the relatively high T gvalues (80°C and 67°C), which is surprising because the high T g Values of 0.05 are generally associated with poor wet rub resistance.

[0079] Aqueous inkjet ink compositions can be characterized by their open-air stability. Observing the time before gelling of an aqueous inkjet ink composition upon exposure to air provides a measure of such stability. This time can be determined as described in the Examples below. In embodiments, the time before gelling is greater than 2 hours, greater than 3 hours, greater than 4 hours, or within the range of 3 to 5 hours. As demonstrated in the Examples, the exemplary aqueous inkjet ink compositions exhibited a time before gelling that was approximately 100% longer than a comparative aqueous inkjet ink composition comprising resin particles formed from a hydrophilic monomer (hydroxyethyl acrylate) in place of a dioxane / dioxolane monomer and a comparative aqueous inkjet ink composition comprising a water-soluble resin in place of the resin particles. This is surprising because hydrophilic monomers and water-soluble resins are expected to provide better stability in open air than resin particles based on amphiphilic dioxane / dioxolane monomers.

[0080] The aqueous inkjet ink composition can be used to form a printed image. In an embodiment, such a method comprises ejecting droplets of any disclosed aqueous inkjet ink composition onto a substrate to form an image thereon. Such a method may further comprise incorporating the ink composition into an inkjet printing device. The printing device may employ a thermal inkjet process, wherein the ink composition in the nozzle is selectively heated in an imaging pattern, thereby causing the droplets of the ink composition to be ejected in an imaging pattern. Alternatively, the printing device may employ an acoustic inkjet process, wherein the droplets of the ink composition are ejected in an imaging pattern by an acoustic beam. In yet another embodiment, the printing device may employ a piezoelectric inkjet process, wherein the droplets of the ink composition are ejected in an imaging pattern by oscillation of a piezoelectric vibrating element. Any suitable substrate may be used.

[0081] The method may include ejecting ink droplets in an image-wise pattern onto an intermediate transfer member, heating the image to partially or completely remove the solvent, and transferring the ink composition from the intermediate transfer member to the final recording substrate in the image-wise pattern. The intermediate transfer member may be heated to a temperature that is higher than the temperature of the final recording sheet and 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 incorporated herein by reference in its entirety.

[0082] Any suitable substrate or recording sheet may be employed as the final recording sheet.

[0083] The use of the latex / resin particles of the present invention is not limited to providing ink compositions. For example, given the adhesive properties of the resin particles described above, latex can be used to provide an adhesive, which is typically 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 latex described herein to a substrate, followed by removing water from the as-deposited latex to form a layer. Various thin film deposition techniques can be used to apply the latex. Any desired substrate can be used, such as paper, polymers, etc. A second substrate can be applied to the layer to form a bonded article, that is, two substrates bonded together via an adhesive therebetween. Any additive disclosed above with respect to the ink composition can be included in the latex to achieve the desired properties of the adhesive. Useful additives can include surfactants, wetting agents, and viscosity-adjusting additives. Any of these additives can be used in the above amounts. 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 also apply to embodiments of the adhesive. A latex comprising water, resin particles, and optionally additives and configured to provide an adhesive can be referred to as an aqueous adhesive composition.

[0084] Example

[0085] The following examples are provided to further define the various aspects of the present disclosure. These examples are intended to be illustrative only and are not intended to limit the scope of the present disclosure. In addition, 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.

[0086] Examples 1-3

[0087] A reactive surfactant solution of 1.1 grams (Hitenol AR 1025 from Montello) and 35 grams of deionized water was prepared by mixing in a glass reactor. The reactants were 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 at this temperature. Separately, 0.3 grams of ammonium persulfate (APS) initiator was dissolved in 5 grams of deionized water and added to the reactor.

[0088] Separately, a monomer emulsion was prepared in the following manner: styrene, butyl acrylate, methacrylic acid, sodium 4-styrenesulfonate (styrenesulfonic acid), dioxane / dioxolane monomer, 1-dodecyl mercaptan (DDT), PEGDA 250, Hitenol AR1025, and deionized water were mixed to form an emulsion. Different amounts of these components were used for each of Examples 1-3 as shown in Table 1. The emulsified mixture was slowly fed into 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 another 1.5 hours. The resulting latex was cooled to room temperature and neutralized to pH 8.0 with 2.5 M KOH solution.

[0089] The latex formulations are shown in Table 1 and the properties are shown in Table 2. The latex was analyzed using a Malvern Nano-ZS for the size of the resin particles, including D- (z，ave) 、D (v，50) (D 50 ) and polydispersity index (PDI). T was measured using a TA Instruments Discovery DSC 2500 in three consecutive heating-cooling-heating cycles at a rate of 10°C / min. g . T g The value is related to the resin particles of the latex.

[0090] Example 4

[0091] In Example 4, the monomer emulsion of Example 2 was used in a different polymerization process. Specifically, the latex was prepared using seeded emulsion polymerization. After preparing the monomer emulsion of Example 2, 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 produces seeds for the polymerization. The polymerization was allowed to react for 30 minutes. Afterwards, the remaining emulsion was fed into the reactor over 1.5 hours, and the reaction was allowed to continue for 2 hours. An additional amount of 0.15 g APS dissolved in DI water was then added to the reactor over 10 minutes, and the reaction was allowed to continue for another 1.5 hours. The latex was then cooled to room temperature and then neutralized to pH 8.0 with 2.5 M KOH solution. The latex formulation is shown in Table 1, and the properties are shown in Table 2.

[0092] Example 5 (Comparative)

[0093] 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 the properties are shown in Table 2.

[0094] Example 6 (Comparative)

[0095] 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 modified. Colloidal silica was also used. The latex formulation is shown in Table 1, and the properties are shown in Table 2.

[0096] Example 7 (Comparative)

[0097] In Example 7, the procedure of Example 1 was repeated, but no dioxane / dioxolane monomer was used, and no hydroxyethyl acrylate was used. The latex formulation is shown in Table 1, and the properties of the latex are shown in Table 2.

[0098]

[0099]

[0100] Examples 8-15

[0101] Aqueous inkjet ink compositions were formed using the latexes of Examples 1, 2, 3, and Comparative Example 5. Another comparative aqueous inkjet ink composition was formed using a water-soluble resin and no resin particles. The following steps were used to form the aqueous inkjet ink compositions, and the formulations are shown in Table 3:

[0102] 1. Add the pigment dispersion to deionized water and mix using a Cowles blade impeller at about 300 RPM for about 15 minutes.

[0103] 2. Slowly add the latex to the pigment dispersion and mix for about 20 minutes (Mixture A).

[0104] 3. In a separate beaker, combine the co-solvent, humectant, stabilizer, defoamer, surfactant, and wetting agent to form a homogeneous mixture (Mixture B).

[0105] 4. Slowly add Mixture B to Mixture A. After the addition is complete, allow the components to mix for an additional 20 minutes.

[0106] 5. Add the wax and continue mixing for about another 15 minutes.

[0107] 6. After mixing, the aqueous inkjet ink composition was left at room temperature for about 60 minutes and then checked for pH, conductivity and surface tension.

[0108]

[0109]

[0110] Aqueous inkjet ink compositions were jetted using a Dimatix DMP2800 printer onto different paper substrates including Kodak paper, gloss#100 and Bold. The first set of key test parameters used are as follows: drop mass = 4.5ng-4.8ng (i.e., about 4.5ng), drop velocity = 6m / s-7m / s, frequency = 5kHz, voltage = 16V-20V, and printing temperature is 20°C to 40°C. The second set of key test parameters used are as follows: drop mass = 8.5ng-9ng (i.e., about 9ng), drop velocity = 9m / s-11m / s, frequency = 5kHz, voltage = 24V-27V, and printing temperature is 20°C to 40°C. The printing parameters are 600×600dpi printing. The measurements were performed using a PIAS II instrument, which is a personal image analysis system with a digital magnifier. The dot size and diameter were measured using a high-resolution optical module of approximately 5μm / pixel with a field of view of approximately 3.2mm×2.4mm. The results are shown in Table 4. The aqueous inkjet ink compositions prepared using the latexes of Examples 1 to 3 were jetted continuously for >10-30 minutes, during which the panel was clean and the nozzles were not clogged. The ink droplets also maintained circular and annular shapes.

[0111] The stability of aqueous inkjet ink compositions in open air was investigated by visually assessing the onset of structure formation, the gelled state, and fully gelled inks. For each study, 4 grams of the test ink was dispensed into identical Pyrex Petri dishes (60 mm d, 10 mm h) along with a control ink in a laboratory environment (32% relative humidity, 22°C) and inspected every 30 minutes for a total test duration of 5 hours. At each inspection interval, the ink dish was gently swirled to assess the severity of structure formation.

[0112] The aqueous inkjet ink compositions were tested for wet rub resistance (20 double rubs using a damp Q-tip) (waterfastness). A thin layer of each inkjet ink composition was coated onto McCoy gloss #100 paper (using a wire wound rod RDS 2.5) and then dried in a convection oven at 130°C for 2 minutes. The numbers in Table 4 indicate the number of double rubs obtained before any removal of the ink was observed (average of 3 measurements).

[0113] Gloss measurements of aqueous inkjet ink compositions were obtained to determine the gloss difference value. Gloss measurements were performed on coated paper substrates using a BYK Gardner Microgloss Meter (75°). After the ink was printed on the paper substrate, the print was left on for 24 hours. The gloss at 75° was measured using a digital Microgloss Meter. The print was then rubbed 30 times with a wipe and the gloss measured again. The difference in gloss before and after the 30 rubs was calculated. The lower the gloss difference, the better the print's robustness against rubbing.

[0114]

[0115]

[0116] As shown in Table 3 (Examples 1-4), the incorporation of amphiphilic dioxane / dioxolane monomers did not have any negative impact on the miniemulsion polymerization, the monomer emulsification step, and the final conversion. In addition, the size distribution (PDI < 0.05) and colloidal stability of the resin particles after accelerated aging testing (3 days at 60°C) were maintained.

[0117] It is noteworthy that the latex / resin particles of Examples 1-4 exhibit pH responsiveness. For example, when the pH increases from 3 to 8, the resin particles of the latex of Example 3 exhibit pH responsiveness. 50 The latex of Example 3 showed an almost 5-fold increase in viscosity. The viscosity was measured using a tuning fork viscometer (Cole-Parmer). The viscosity at 40% solids, room temperature, and pH 3 was 37 cP; the viscosity at 34.4% solids, room temperature, and pH 8 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.

[0118] The aqueous inkjet ink compositions of Examples 8-12 (made using the latex / resin particles of Examples 1-3) exhibited excellent printing performance, showing improved jetting (no misdirectionality and satellites, jetting >30 minutes), latency, and decap time. 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 roundness, and lines and solid blocks showed similar or better surface coverage than Comparative Examples 13-15.

[0119] In addition, the use of dioxane / dioxolane monomers significantly improved the mechanical properties of the printing ink, as evidenced by an increase in waterfastness (wet rub resistance) and a decrease in gloss differential. (See Table 4.) This is particularly surprising because the T values of the resin particles in Examples 9 and 11 were g are very high (80°C and 67°C respectively). As in the case of Comparative Example 14, high T g Values of 0.0000 are generally associated with poor wet rub resistance and high gloss variance.

[0120] Finally, the use of dioxane / dioxolane monomers greatly improves the open-air stability of aqueous inkjet ink compositions. Aqueous inkjet ink composition Examples 8-12 (made from the latex / resin particles of Examples 1-3) exhibited extended flow times and a delay in the onset of structure formation (gelation) after exposure to open-air flow. Specifically, they showed improvements in the onset and progression of gelation of at least 1-2 hours. This represents an improvement of over 100% relative 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 (PEG 4000). Compared to the amphiphilic dioxane / dioxolane monomers of Examples 8-12, these components would be expected to inhibit gelation.

[0121] 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. Furthermore, for the purposes of this disclosure and unless otherwise specified, "a" or "an" means "one or more."

[0122] If not already included, all numerical values for parameters in this disclosure are intended to be preceded by the term "approximately." This encompasses those variations inherent in the measurement of the relevant parameter, as understood by one of ordinary skill in the art. This also encompasses the exact value of the disclosed value as well as values rounded to the disclosed value.

[0123] The foregoing description of the exemplary embodiments of the present disclosure has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the present disclosure to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from the practice of the present disclosure. The embodiments are selected and described to explain the principles of the present disclosure and as a practical application of the present disclosure, so that those skilled in the art can utilize the present disclosure in various embodiments and to consider various modifications suitable for specific uses. The scope of the present disclosure is intended to be defined by the appended claims and their equivalents.

Claims

1. A latex comprising water and resin particles, wherein the resin particles comprise a polymerization product of reactants comprising: Glycerol formal (meth) acrylate; styrene; alkyl (meth) acrylate; methacrylic acid, styrene sulfonic acid, or methacrylic acid and styrene sulfonic acid; a reactive surfactant; a multifunctional monomer; and optionally, a chain transfer agent, an initiator, or a chain transfer agent and an initiator, wherein the room temperature viscosity of the resin particles at a solid content of 30% and a pH of 3 is in the range of 10 cP to 100 cP, Further, wherein the latex does not contain any other polymer other than that provided by the resin particles; wherein the glycerol formal (meth)acrylate is present in an amount of 2 wt % to 18 wt %; Styrene and an alkyl (meth)acrylate are present, together in an amount of 70% to 97% by weight; methacrylic acid, styrenesulfonic acid, or methacrylic acid and styrenesulfonic acid are present, together in an amount of 2% to 20% by weight; The multifunctional monomer is present in an amount of 0.001 wt % to 1 wt %, wherein the amount is compared to the total amount of monomers in the resin particles, the total amount of monomers excluding reactive surfactants; and The room temperature viscosity was measured using a tuning fork vibrating viscometer.

2. The latex according to claim 1, wherein the D of the resin particles 50 The particle size depends on the pH of the latex, where D 50 Particle size was measured using a Malvern Zetasizer Nano ZS.

3. The latex according to claim 2, wherein the D at pH 8 50 The particle size is larger than that at pH 3. 50 granularity.

4. The latex according to claim 3, wherein the D at pH 8 50 The particle size is at least 15% larger.

5. The latex according to claim 1, wherein the resin particles have a pH of 3. 50 The particle size is no greater than 100nm.

6. The latex of claim 1, wherein the latex has a room temperature viscosity at 30% solids content that depends on the pH of the latex.

7. The latex of claim 6, wherein the room temperature viscosity at 30% solids and pH 8 is greater than the room temperature viscosity at 30% solids and pH 3.

8. The latex according to claim 7, wherein the room temperature viscosity at a solid content of 30% and a pH of 8 is twice the room temperature viscosity at a solid content of 30% and a pH of 3.

9. The latex according to claim 1, wherein the resin particles have a glass transition temperature T in the range of 50°C to 100°C. g , where the glass transition temperature T g Measured using differential scanning calorimetry.

10. The latex of claim 1 , wherein the resin particles are comprised of the polymerization product of reactants consisting of: Glycerol formal (meth)acrylate; styrene; alkyl (meth)acrylate; methacrylic acid, styrene sulfonic acid, or methacrylic acid and styrene sulfonic acid; reactive surfactant; multifunctional monomer; and optionally, a chain transfer agent, an initiator, or a chain transfer agent and an initiator.

11. A latex consisting of water and resin particles comprising the polymerization product of reactants comprising: Glycerol formal (meth)acrylate; styrene; alkyl (meth)acrylate; methacrylic acid, styrene sulfonic acid, or methacrylic acid and styrene sulfonic acid; a reactive surfactant; a multifunctional monomer; and optionally, a chain transfer agent, an initiator, or a chain transfer agent and an initiator; wherein the glycerol formal (meth)acrylate is present in an amount of 2 wt % to 18 wt %; Styrene and an alkyl (meth)acrylate are present, together in an amount of 70% to 97% by weight; methacrylic acid, styrenesulfonic acid, or methacrylic acid and styrenesulfonic acid are present, together in an amount of 2% to 20% by weight; The multifunctional monomer is present in an amount of 0.001 wt % to 1 wt %, wherein said amount is compared to the total amount of monomers in the resin particles, said total amount of monomers excluding the reactive surfactant. 12 . The latex according to claim 11 , wherein the room temperature viscosity of the resin particles at a solid content of 30% and pH 3 is in the range of 10 cP to 100 cP, wherein the room temperature viscosity is measured using a tuning fork vibration viscometer.

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