Seeded emulsion polymerization process for latexes and aqueous inkjet ink compositions made therefrom

Abstract

To provide a methods for forming a latex.SOLUTION: A method for forming a latex comprises adding a first portion of a monomer emulsion comprising water, a monomer, an acidic monomer, a multifunctional monomer, and a first reactive surfactant to a reactive surfactant solution comprising water and a second reactive surfactant to form a reaction mixture, wherein the reactive surfactant solution does not comprise monomers other than the second reactive surfactant; adding a first portion of an initiator solution to the reaction mixture so that monomers undergo polymerization reactions to form resin seeds in the reaction mixture; adding a second portion of the monomer emulsion to the reaction mixture comprising the resin seeds; and adding a second portion of the initiator solution to the reaction mixture to form a latex comprising resin particles.SELECTED DRAWING: None

Description

[Background technology]

[0001] Latex is often used in aqueous inkjet ink compositions to bind colorants to the substrate and protect the printed image. High-quality latex is important to prevent spray instability, spray latency, and nozzle clogging during printing of aqueous inkjet ink compositions. Various polymerization processes exist that are used to produce latex for aqueous inkjet ink compositions. Nevertheless, it has been difficult to produce latex quickly and efficiently without sacrificing quality. [Overview of the project]

[0002] This disclosure provides a method for forming latex for use in various applications, such as binders in aqueous inkjet ink compositions. Embodiments of the method provide improved control over the emulsification and polymerization processes to ensure the achievement of resin particles with small diameter and a narrow particle size distribution. This contributes to the high quality of the resulting latex. Embodiments of the method require fewer components (e.g., no surfactant) and / or fewer components (e.g., fewer initiators), while the latex is produced very rapidly (e.g., in less than 5 hours). Embodiments of the resulting latex are very stable and have an adjustable glass transition temperature T g It also has a sufficiently low T to achieve bonding of aqueous inkjet ink compositions containing resin particles at room temperature (i.e., 20°C to 25°C). g Values ​​can be achieved. Latex and aqueous inkjet ink compositions are also included in this disclosure.

[0003] In one embodiment, a method for forming a latex is provided. In an embodiment, such a method is to form a reaction reaction by adding a first portion of a monomer emulsion containing water, a monomer, an acidic monomer, a polyfunctional monomer, and a first reactive surfactant to a reactive surfactant solution containing water and a second reactive surfactant, wherein the reactive surfactant solution does not contain monomers other than the second reactive surfactant; to add a first portion of an initiator solution to the reaction mixture such that the monomer undergoes a polymerization reaction to form resin seeds in the reaction mixture; to add a second portion of the monomer emulsion to the reaction mixture containing the resin seeds; and to add a second portion of the initiator solution to the reaction mixture to form a latex containing resin particles.

[0004] In another embodiment, a latex is provided. In this embodiment, such a latex comprises resin particles comprising a polymerization product of a reaction comprising monomers other than styrene, an acidic monomer, a polyfunctional monomer, and a reactive surfactant, wherein the resin particles have a diameter of about 100 nm or less. 50 D 90 It has a particle size and a width of approximately 45 nm or less.

[0005] 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]

[0006] latex

[0007] In one embodiment, a method for forming latex is provided. The latex resin particles are synthesized from various monomers to form a polymer material constituting the resin particles. The type of monomer and therefore the polymer material is not particularly limited. However, as an example, the following monomers and combinations thereof can be used (for example, the use of "(meth)" such as "(meth)acrylate" refers to both acrylate and methacrylate): styrene; alkyl (meth)acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, dodecyl acrylate, n-octyl acrylate, 2-chloroethyl acrylate, methyl methacrylate, ethyl methacrylate, and butyl methacrylate; β-carboxyethyl acrylate (β-CEA), phenyl acrylate, methyl alpha chloroacrylate; butadiene; isoprene; methacrylonitrile; acrylonitrile; vinyl methacrylate Vinyl ethers such as ethyl 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-vinyl indole; 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. In some embodiments, the monomers used to form latex resin particles include styrene and alkyl acrylates. In some embodiments, the monomers used to form latex resin particles include two different alkyl acrylates (e.g., methyl (meth)acrylate and butyl (meth)acrylate). In some embodiments, styrene is not used.The use of alkyl acrylates and the elimination of styrene are useful in providing latex that facilitates film formation and bonding of aqueous inkjet ink compositions containing latex.

[0008] In embodiments in which the monomer comprises either styrene / alkyl acrylate or two different alkyl acrylates, the weight ratio of the different monomers is the desired T g For example, T within the range described below g The values ​​can be adjusted to achieve the desired result. In embodiments, the weight ratio of (styrene) to (alkyl acrylate) is 10:1 to 1:1, 8:1 to 2:1, and 7:1 to 3:1. In embodiments, the weight ratio of the first alkyl acrylate (e.g., methyl (meth)acrylate) to the second alkyl acrylate (e.g., butyl (meth)acrylate) is 5:1 to 1:5, 3:1 to 1:3, and 2:1 to 1:2. These weight ratios refer to the weight ratio of each monomer in the monomer emulsion in which the resin particles are formed. They also refer to the weight ratio of each monomer in the resin particles, as the monomer conversion rate in this method was determined to be greater than 99.9%.

[0009] An acidic monomer may be used to form resin particles of a latex, including (meth)acrylic acid monomers, sulfonic acid monomers, sulfonate monomers, and combinations thereof. Exemplary acidic monomers include acrylic acid, methacrylic acid, ethacrylic acid, dimethylacrylic acid, maleic anhydride, maleic acid, styrenesulfonic acid, 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 methacrylate, sulfopropyl acrylate, styrenesulfonic acid, sulfoethyl acrylate, 2-methacryloyloxymethane-1-sulfonic acid, 3-methacryloyloxypropane-1-sulfonic acid, 3-(vinyloxy)propane-1-sulfonic acid, ethylenesulfonic acid, vinyl sulfuric acid, 4-vinylphenyl sulfuric acid, ethylenephosphonic acid, vinyl phosphoric acid, vinyl benzoic acid, 2-acrylamido-2-methyl-1-propanesulfonic acid, and combinations thereof. These acidic monomers also include their salts, for example, salts of sulfonic acid.

[0010] In an embodiment, two different acidic monomers each having a different pK a value are used to form resin particles of a latex. 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 respect to the acidic monomer having . This ranges from 0.5 to 8 and 1 to 6. In embodiments, the two different types of acidic monomers used to form resin particles include methacrylic acid and sulfonic acid.

[0011] Hydrophilic monomers may be used to form latex resin particles. The term “hydrophilic monomer” is distinguished from the “acidic monomer” described above. That is, selected acidic monomers may also be hydrophilic, but these terms refer to different, chemically distinct species of monomers. Hydrophilic monomers are useful for improving the freeze-thaw stability of the latex formed from them, as well as the latency of aqueous inkjet ink compositions. Hydrophilic monomers are generally monofunctional, i.e., they contain a single polymerizable group. Exemplary hydrophilic monomers include hydroxyethyl (meth)acrylate, n-hydroxyethyl (meth)acrylamide, hydroxypropyl (meth)acrylate, and hydroxypropyl (meth)acrylamide, ethylene glycol (meth)acrylate, propylene glycol (meth)acrylate, poly(ethylene glycol) (meth)acrylate with molecular weights of 200 g / mol to 2000 g / mol, and poly(propylene glycol) (meth)acrylate with molecular weights of 200 g / mol to 2000 g / mol, as well as combinations thereof. In both cases, this includes molecular weights ranging from 500 g / mol to 1000 g / mol. These molecular weights can be determined using gel permeation chromatography (GPC). In embodiments, the hydrophilic monomer used to form the resin particles includes poly(ethylene glycol) methacrylate.

[0012] Polyfunctional monomers may be used to form latex 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. Examples of polyfunctional monomers include poly(ethylene glycol) di(meth)acrylates, such as difunctional monomers like poly(ethylene glycol) diacrylates having molecular weights of 200 g / mol to 2000 g / mol. These difunctional monomers may also be considered hydrophilic as described above. Other hydrophilic bifunctional monomers include diacrylate compounds bonded to alkyl chains containing ether bonds, such as diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol #400 diacrylate, polyethylene glycol #600 diacrylate, and dipropylene glycol diacrylate; 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 exemplary 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 acrylate, and compounds obtained by substituting the acrylate of these compounds with methacrylate.

[0013] Reactive surfactants may be used to form latex resin particles. Suitable reactive surfactants contain polymerizable (and therefore reactive) groups such that they are incorporated into the resin particles. Exemplary reactive surfactants include anionic ether sulfate reactive surfactants such as those from the commercially available Hitenol BC series, such as Hitenol BC10-25. Other suitable reactive surfactants include polyoxyethylene alkylphenyl ether ammonium sulfate, Hitenol BC-10, BC-20, BC-2020, BC-30; polyoxyethylene styrene-phenyl ether ammonium sulfate containing Hitenol AR-10, AR-20, AR10-25, AR-2020; nonionic polyoxyethylene alkylphenyl ethers containing Noigen RN-10, RN-20, RN-30, RN-40, RN-5065; and reactive surfactants available from Ethox containing E-sperse RX-201, RX-202, RX-203, RS-1596, RS-1616, RS-1617, RS-1618, RS-1684.

[0014] A chain transfer agent may be used to form the latex. The chain transfer agent may be a mercaptan or a thiol. Suitable chain transfer agents include n-dodecylmercaptan (NDM), n-dodecanethiol (DDT), tert-dodecylmercaptan, 1-butanethiol, 2-butanethiol, octanthiol, and combinations thereof. Carbon halides such as carbon tetrabromide, carbon tetrachloride, and combinations thereof may be used as chain transfer agents.

[0015] When forming the latex, any of the monomers described above can be used in a monomer emulsion containing a solvent. Water is generally used as the solvent, but water-soluble or water-miscible organic solvents (e.g., ethanol) can also be included. The types of monomers and their relative amounts may be selected to adjust the properties of the resin particles / latex.

[0016] The acidic monomer may be used in the monomer emulsion in an amount ranging from 1.5% to 15% by weight. (Here, % by weight is (total weight of acidic monomer) / (total weight of monomers in the monomer emulsion excluding the reactive surfactant) * × 100). This range includes 5% to 10% by weight. As described above, two different types of acidic monomers having different pK a values may be used in the weight ratios described above. The hydrophilic monomer may be used in the monomer emulsion in an amount ranging from 0% to 10% by weight. (% by weight has a similar meaning as that described for the acidic monomer.) This range includes 0.1% to 8% by weight, and 1% to 8% by weight. The polyfunctional monomer containing the bifunctional monomer may be used in the monomer emulsion in an amount ranging from 0.01% to 5% by weight, 0.1% to 5% by weight, or from 0.1% to 1% by weight. (% by weight has a similar meaning as that described for the acidic monomer.) Other monomers (e.g., styrene, alkyl acrylate) may be present in an amount ranging from 70% to 97% by weight. (% by weight has a similar meaning as that described for the acidic monomer.) This range includes 75% to 90% by weight. As described above, these monomers can be used in the weight ratios described above.

[0017] Together, the amounts of acidic monomer, hydrophilic monomer, and polyfunctional monomer (e.g., hydrophilic polyfunctional monomer) may be present in the monomer emulsion in the range of 1.5 wt% to 20 wt%. (Here, wt% is (total weight of acidic monomer, hydrophilic monomer, and polyfunctional monomer) / (total weight of monomers in the monomer emulsion excluding the reactive surfactant) * × 100). This range includes 2 wt% to 20 wt% and 5 wt% to 20 wt%.

[0018] The reactive surfactant may be used in the monomer emulsion in an amount in the range of 1.5 wt% to 6.5 wt%. (Here, wt% is (total weight of the 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%.

[0019] The chain transfer agent may be present in the monomer emulsion and may be used in various suitable amounts, for example, from about 0.25 wt% to about 2.5 wt%. (Here, wt% is (total weight of the chain transfer agent) / (total weight of monomers in the monomer emulsion excluding the reactive surfactant) * × 100).

[0020] In the embodiment, the monomer emulsion comprises (or consists of) a solvent (e.g., water), styrene, an alkyl acrylate (e.g., butyl acrylate), an acidic monomer, a polyfunctional monomer (e.g., a difunctional monomer), and a reactive surfactant. In such embodiment, one or a variety of different monomers may be used. Similarly, one or a variety of solvents may be used. In the embodiment, the monomer emulsion comprises (or consists of) a solvent (e.g., water), styrene, an alkyl acrylate (e.g., butyl acrylate), two different types of acidic monomers (e.g., methacrylic acid and sulfonic acid), a difunctional monomer (e.g., poly(ethylene glycol) diacrylate), and a reactive surfactant. In the embodiment, the monomer emulsion comprises (or consists of) a solvent (e.g., water), a first alkyl acrylate (e.g., methyl methacrylate), a second alkyl acrylate (e.g., butyl acrylate), an acidic monomer, a polyfunctional monomer (e.g., a difunctional monomer), and a reactive surfactant. In such embodiment, one or a variety of different monomers may be used. Similarly, one or different types of solvents may be used. In embodiments, the monomer emulsion comprises (or consists of) a solvent (e.g., water), a first alkyl acrylate (e.g., methyl methacrylate), a second alkyl acrylate (e.g., butyl acrylate), two different types of acidic monomers (e.g., methacrylic acid and sulfonic acid), a bifunctional monomer (e.g., poly(ethylene glycol) diacrylate), and a reactive surfactant. In any of these embodiments, a hydrophilic monomer may be included (e.g., poly(ethylene glycol) methacrylate). In any of these embodiments, a chain transfer agent may be included. In any of these embodiments, various amounts of monomers and chain transfer agents as described above may be used. The remainder may consist of a solvent.

[0021] In at least some embodiments, the monomer emulsion is styrene-free (i.e., does not contain styrene).

[0022] In at least one embodiment, the monomer emulsion is surfactant-free (i.e., does not contain any surfactants). Here, “surfactant” refers to unreactive and 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 unreactive and non-polymerizable cationic surfactants such as alkylbenzyldimethylammonium chloride, dialkylbenzenealkylammonium chloride, lauryltrimethylammonium chloride, alkylbenzylmethylammonium chloride, alkylbenzyldimethylammonium bromide, benzalkonium chloride, cetylpyridinium bromide, trimethylbromide, quaternary polyoxyethylalkylamine halogenated 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. Therefore, monomer emulsions may be free of (i.e., contain) any of these surfactants.

[0023] The processing step for forming the latex includes adding a first portion of any of the above-described monomer emulsions to a reactive surfactant solution at a supply rate over a period of time. The first portion of the monomer emulsion added to the reactive surfactant solution refers to a portion of the total amount of monomer emulsion used in the method for forming the latex. This first portion may be in the range of 1% to 20% by volume of the total amount of monomer emulsion. This includes 2% to 15% by volume and 5% to 10% by volume. The remainder of the monomer emulsion is used in later steps of the method, as described below. The supply rate at which the first portion of the monomer emulsion is added may be in the range of 1 mL / min to 10 mL / min based on a total reaction volume of 1 L. The time for which the first portion of the monomer emulsion is added may be in the range of 5 minutes to 100 minutes.

[0024] A reactive surfactant solution comprises a solvent and a reactive surfactant. Any of the solvents and reactive surfactants listed above may be used. One or different types of solvents and / or reactive surfactants may be used. The reactive surfactant in the reactive surfactant solution may be the same or different type compared to the reactive surfactant that may be present in the monomer emulsion. The reactive surfactant solution may further contain a buffer. Various buffers such as sodium bicarbonate, sodium carbonate, and ammonium hydroxide may be used. The reactive surfactant may be used in an amount ranging from 1% to 10% by weight. (where wt% is (total weight of reactive surfactant) / (total weight of reactive surfactant solution)) * (Refers to 100.) This range includes 2% by weight to 5% by weight. The buffer can be used in amounts ranging from 0.25% by weight to 2.5% by weight. (Weight % has the same meaning as described above.)

[0025] In some embodiments, the reactive surfactant solution comprises (or consists of) a solvent (e.g., water), a reactive surfactant, and optionally a buffer. In such embodiments, one or different types of these components may be used. In any of these embodiments, the amounts of reactive surfactant and buffer may be as described above. The remainder may consist of a solvent. In at least some embodiments, the reactive surfactant solution is free of (i.e., does not contain) any of the surfactants described above. In at least some embodiments, the reactive surfactant solution is free of (i.e., does not contain) any monomers other than the reactive surfactant monomer present in the solution. In at least some embodiments, the reactive surfactant solution is initiator-free (i.e., does not contain).

[0026] The addition of the first portion of the monomer emulsion to the reactive surfactant solution may be carried out under the influence of an inert gas (e.g., nitrogen) and at a high temperature (e.g., 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 first portion of the monomer emulsion, and continuing this heating during the addition of the first portion of the monomer emulsion.

[0027] Next, a first portion of the initiator solution is added to the first portion of the monomer emulsion / reactive surfactant solution combination (i.e., the “reaction mixture”) at a certain supply rate over a certain period of time. The first portion of the initiator solution added to the reaction mixture refers to a portion of the total amount of initiator solution used in the method for forming the latex. This first portion may be in the range of 10% to 90% by volume of the total amount of initiator solution. This includes 12% to 85% by volume and 15% to 75% by volume. The remainder of the initiator solution is used in later steps of the method, as described below. This supply rate may be in the range of 1 mL / min to 10 mL / min based on 1 L of total reaction volume. The time over which the initiator solution is added may be in the range of 0.1 min to 10 min, 0.5 min to 5 min, and 0.5 min to 3 min. The addition of the initiator solution may be carried out under high temperature and inert gas, as described above. In the presence of the initiator, the monomers of the monomer emulsion undergo polymerization reactions to form resin seed particles in the reaction mixture.

[0028] The initiator solution comprises an initiator and one of the solvents described above. One or different types of solvents and / or initiators may be used. Examples of suitable initiators include water-soluble initiators such as ammonium persulfate (APS), sodium persulfate, and potassium persulfate, as well as organically soluble initiators containing organic peroxides and azo compounds, including Vazo peroxides such as VAZO 64 (trademark), 2-methyl-2-2'-azobispropannitrile, VAZO 88 (trademark), 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 0.1% to 2.5% by weight.(Here, weight % is (total weight of initiator) / (total weight of initiator solution). * (It refers to 100.)

[0029] Next, the second portion of the monomer emulsion is added to the reaction mixture, this time containing the resin seed, at a certain rate over a set period of time. The amount of this second portion may be the remainder of the total amount of monomer emulsion used in the method for forming the latex. The rate and time of this addition may be within the ranges described above for the first portion, but they do not need to be the same as those used for the first portion. The addition of the second portion may be carried out under high temperature and inert gas conditions, as described above.

[0030] A second portion of the initiator solution is also added to the reaction mixture. The amount of this second portion may be the remainder of the total amount of initiator solution used in the method for forming the latex. The second portion of the initiator solution may be added intermittently (i.e., in separate portions) or continuously (i.e., at a supply rate) during the addition of the second portion of the monomer emulsion described above. These embodiments, including the distribution of the initiator solution, can significantly reduce the total amount of initiator or total reaction time required to achieve resin particles of a desired diameter. Alternatively, the second portion of the initiator solution may be added at a certain supply rate and time, but after the addition of the second portion of the monomer solution is complete. In this case, the supply rate and time may be within the range described above for the addition of the first portion of the initiator solution, but they do not need to be the same. The addition of the second portion of the initiator solution may be carried out under high temperature and inert gas conditions, as described above.

[0031] The addition of the second part of the monomer emulsion and the additional amount of initiator solution allows for further polymerization reactions between the monomers, growing the resin seeds into latex resin particles.

[0032] The “holding” time may be included during any of the steps described above, i.e., the time during which the reaction mixture is simply held at a desired temperature (e.g., high temperature) without the addition of any components. These times may be in the range of 1 minute to 2 hours, e.g., 1 minute to 1 hour and 1 minute to 20 minutes. The method may include a final holding period in the range of 1 hour to 5 hours or 1 hour to 3 hours. The temperature used for the final holding may be higher than the temperatures used during other steps of the method, e.g., higher than high temperature. This temperature in the final holding may be in the range of 70°C to 100°C or 75°C to 95°C.

[0033] The result of the above steps is latex containing resin particles. Optionally, the formed latex can be processed by standard techniques such as solidification, dissolution, and precipitation, filtration, washing, or drying.

[0034] It should be noted that, at least in the embodiments, this method does not involve the use of any of the surfactants described above (other than reactive surfactant monomers).

[0035] 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.

[0036] As described above, the latex formed by this method includes resin particles. The composition of the resin particles depends on the selection of monomers and their relative amounts, as well as the polymerization reaction between the selected monomers that produces the polymerization product described above. Thus, a variety of compositions are encompassed, including those based on various polymerization products of reactants containing various combinations of monomers. As described above, the selection of monomers is not particularly limited. However, in embodiments, the resin particles include (or consist of) polymerization products (e.g., copolymers) of reactants containing styrene, alkyl acrylates (e.g., butyl acrylate), acidic monomers, polyfunctional monomers (e.g., difunctional monomers), and reactive surfactants. In such embodiments, one or a variety of different types of monomers may be present. In embodiments, the resin particles include (or consist of) polymerization products of reactants containing styrene, alkyl acrylates (e.g., butyl acrylate), two different types of acidic monomers (e.g., methacrylic acid and sulfonic acid), difunctional monomers (e.g., poly(ethylene glycol) diacrylate), and reactive surfactants. In the embodiments, the resin particles comprise (or consist of) a polymerization product of a reaction comprising a first alkyl acrylate (e.g., methyl methacrylate), a second alkyl acrylate (e.g., butyl acrylate), an acidic monomer, a polyfunctional monomer (e.g., a difunctional monomer), and a reactive surfactant. In the embodiments, the resin particles comprise (or consist of) a polymerization product of a reaction comprising a solvent (e.g., water), a first alkyl acrylate (e.g., methyl methacrylate), a second alkyl acrylate (e.g., butyl acrylate), two different types of acidic monomers (e.g., methacrylic acid and sulfonic acid), a difunctional monomer (e.g., poly(ethylene glycol) diacrylate), and a reactive surfactant. In each of these embodiments, the reaction may include a hydrophilic monomer, e.g., poly(ethylene glycol) methacrylate. In each of these embodiments, initiators 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 / difunctional monomer.In each of these embodiments, monomers may be present in the resin particles in the amounts described above. For example, the amounts of acidic monomers, hydrophilic monomers, and polyfunctional monomers together may be in the range of 1.5% to 20% by weight in the resin particles. As described above, this weight percentage is (total weight of acidic monomers, hydrophilic monomers, and polyfunctional monomers) / (total weight of monomers in the resin particles excluding reactive surfactants). * It refers to 100.

[0037] The latex resin particles of the present invention can be characterized by their diameter. The diameter of the resin particles is D 50 Particle size can be reported, which refers to diameter, in which case 50% (based on volume) of the sample consists of particles with a diameter less than the stated diameter value. 50 Particle size can be measured using the Malvern Zetasizer Nano ZS. This instrument uses laser light scattering technology to measure the Doppler shift light generated from each particle in motion (Brownian motion). The signals generated by these shifts are proportional to the particle diameter. The signals are mathematically converted into particle size and particle size distribution. The analysis can be performed using an external probe or by inserting the probe into a fixed sample chamber. In the embodiment, D 50 The particle size is 100 nm or less, 90 nm or less, 80 nm or less, 75 nm or less, or in the range of 40 nm to 100 nm, or in the range of 50 nm to 80 nm.

[0038] Similarly, the latex resin particles of the present invention can be characterized by their particle size distribution. The particle size distribution can be reported as the width of the peaks measured using a nanoparticle analyzer. In embodiments, the width is in the range of 45 nm or less, 40 nm or less, 35 nm or less, or 25 nm to 35 nm.

[0039] Due to their small diameter and narrow particle size distribution, the latex resin particles of the present invention can be further characterized as being free of large particles (i.e., not containing them). This includes particles smaller than 150 nm, smaller than 125 nm, or smaller than 100 nm. 95This can be proven by the value. D 95 The value refers to the diameter, and in this case, 95% of the sample (based on volume) consists of particles with a diameter less than that diameter value. Also, using Malvern Zetasizer Nano ZS, D 95 The value can be measured.

[0040] This latex also has those T g It can be characterized by a value and can be measured using a differential scanning calorimetry (DSC) instrument. In the embodiment, T g This range is approximately 20°C to 100°C. This includes the ranges of 35°C to 80°C, 50°C to 80°C, 20°C to 50°C, and 25°C to 45°C.

[0041] Water-based inkjet ink composition

[0042] Any of the latexes listed above may be used to provide an aqueous inkjet ink composition. Resin particles may be present in the aqueous inkjet ink composition in an amount ranging from 1% 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.

[0043] Solvent system

[0044] 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.

[0045] 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; urea; diethylene glycol; 1,2,4-butanetriol; glycerol; diglycerol; triethylene glycol; polyethylene glycol 200; and polyethylene glycol 600.

[0046] 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.

[0047] 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.

[0048] 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.)

[0049] Water-soluble resin

[0050] Water-soluble resins may be used in aqueous inkjet ink compositions, although in some embodiments, water-soluble resins are not used. The type and amount may also be selected to achieve the desired viscosity. Exemplary water-soluble resins include polyethylene glycol and polyvinylpyrrolidone. The molecular weight of the water-soluble resin can be in the range of 1,000 g / mol to 10,000 g / mol. In embodiments, the water-soluble resin is polyethylene glycol having molecular weights in the range of 3,000 g / mol to 9,000 g / mol, 3,000 g / mol to 7,000 g / mol, 3,000 g / mol to 5,000 g / mol, or 4,000 g / mol. These molecular weight values ​​can be determined using gel permeation chromatography. In embodiments, the amount of water-soluble resin is selected such that the total solids content of the aqueous inkjet ink composition (generally provided by latex, water-soluble resin, and colorant) is 5% to 15% by weight, 6% to 12% by weight, or 7% to 10% by weight. (Here, weight % is (total weight of solids) / (total weight of water-based inkjet ink composition)) * (It refers to 100.)

[0051] The aqueous inkjet ink composition may further contain other binder resins, including styrene-acrylic copolymers and vinylpyrrolidone copolymers, urethane or polyurethane dispersions, and acrylic polymers such as acrylic-urethane hybrid dispersions. More specific binder resins that may be used include those available from Johnson Polymers (BASF), such as Joncryl 661, Joncryl 8003, Joncryl 8078, Joncryl 8082, Joncryl 537, Joncryl H538, Joncryl H538, and Joncryl HPD 71E. Other exemplary water-soluble resins include Rhoplex I-1955, Rhoplex I-2426D, Rhoplex I-62, Rhoplex I-98, and Rhoplex E-1691, available from Rhohm & Haas. Other examples 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. In this embodiment, no such binder resins are used.

[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), chromium yellow (PbCrO4), and iron oxide 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 a variety of 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, 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 latex, water-soluble resin, and colorants) is 5% to about 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] surfactant

[0059] Unlike the latex described above, water-based 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 (such as Surfynol® 104 series, Surfynol® 400 series, Dynol® 604, Dynol® 607, Dynol® 810, EnviroGem® 360, Tergitol® 15-s-7, Tergitol® 15-s-9, TMN-6, TMN-100x, and secondary alcohol ethoxylate series such as Tergitol® NP-9 and Triton® X-100), and cationic surfactants (such as 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 can also be used, such as alkyl betaine fluorosurfactants or alkylamine oxide fluorosurfactants, such as Chemguard S-500 and Chemguard S-111.

[0060] 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.

[0061] additives

[0062] Various additives can be used in aqueous inkjet ink compositions to adjust their properties. Suitable additives include one or more of the following: biocides, fungicides, stabilizers, acids or bases, phosphates, carboxylates, sulfites, amine salts, pH adjusters such as buffers, metal ion sequestering agents such as EDTA (ethylenediamine tetraacetic acid), defoamers, and wetting agents.

[0063] 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.

[0064] In at least one embodiment, the aqueous inkjet ink composition is free of coagulants (i.e., does not contain), flocculants (i.e., does not contain), and plasticizers (i.e., does not contain). In the embodiment, the ink composition is free of any pyrrolidone-based solvent such as N-methylpyrrolidone (i.e., does not contain), and free of Texanol and Texanol isobutyrate (i.e., does not contain).

[0065] Similarly, the aqueous inkjet ink composition of the present invention may be free of (i.e., not contain) resins other than those provided by the latex of the present invention. A single type of latex (containing a single type of resin particles) may be used.

[0066] In the embodiments, the aqueous inkjet ink composition comprises (or consists of) a solvent system, resin particles, a colorant, and optionally one or more water-soluble resins and additives. In the embodiments, the aqueous inkjet ink composition comprises (or consists of) a solvent system, resin particles, a colorant, a water-soluble resin, and optionally additives. In any of these embodiments, the additive may be selected from stabilizers, surfactants, defoamers, wetting agents, and biocides. In any of these embodiments, the components may be selected from the solvent system, resin particles, colorants, water-soluble resins, and additives disclosed herein. In any of these embodiments, any amount of the components described above may be used. In any of these embodiments, a single type of resin particle may be used.

[0067] Aqueous inkjet ink compositions 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. Mixing and / or heating may be used in the method. The aqueous inkjet ink composition may be filtered before use.

[0068] 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.

[0069] 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.

[0070] Any suitable substrate or recording sheet can be used as the final recording sheet. Examples of substrates include McCoy® Gloss #100 coated substrate, Xerox® Bold uncoated substrate, Kodak photographic paper, Sterling® Ultra Web Matte (offset coating), TrueJet® Gloss Text (inkjet coated), and McCoy® Silk (offset coating). [Examples]

[0071] The following examples are presented to further define the various types of the disclosure. These examples are for illustrative purposes only and are not intended to limit the scope of the disclosure. Unless otherwise stated, proportions and percentages are by weight. As used herein, “room temperature” refers to a temperature of about 20°C to about 25°C. Example 1 (Control)

[0072] A reactive surfactant solution was prepared by mixing 3.2 grams of Hitenol BC1025 (from Montello), 72 grams of deionized water, and 0.8 g of NaHCO3 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 85°C and maintained there. Separately, 0.2 grams of ammonium persulfate (APS) initiator was dissolved in 5 grams of deionized water and added to the reactor.

[0073] Separately, a monomer emulsion was prepared in the following manner: 64 g of styrene, 10 g of butyl acrylate, 6 g of methacrylic acid, 1.2 g of 1-dodecanethiol (DDT), 0.24 g of PEGDA 250, 1.6 g of Hitenol BC 1025, and 30 g of deionized water were mixed intermittently to form an emulsion. The emulsion mixture was slowly supplied to the reactor for 3 hours, and the reaction was continued for 15 hours.

[0074] The dimensions of the resin particles were analyzed using Malvern Nano-ZS. The following parameters were used: D 50 =76nm, and D 95 A peak with a wavelength of 108 nm and a peak width of 33 nm was observed.

[0075] Differential Scanning Calorimetry (DSC) using Instruments Discovery DSC 2500 g The latex T was measured. g The temperature was 76°C. Example 2

[0076] A reactive surfactant solution was prepared in a 500 mL round-bottom reactor by stirring at 250 rpm with 2.8 g of Hitenol BC 1025 (from Montello), 72 g of deionized water, and 0.4 g of NaHCO3, and continuously purging with nitrogen. The reactor was then heated to a maximum of 85°C and maintained there. No initiator or initiator solution was added.

[0077] Separately, a monomer emulsion was prepared in the following manner: 62 g of styrene, 10 g of butyl acrylate, 6 g of methacrylic acid, 1.0 g of styrene sulfonic acid, 1.2 g of 1-dodecanethiol (DDT), 0.24 g of PEGDA 250, 1.36 g of Hitenol BC 1025, and 32 g of deionized water were mixed to form an emulsion.

[0078] 9.1 g (8%) of monomer emulsion was slowly supplied to the reactor and held for 1 to 5 minutes. Next, 10 g of APS solution (0.5 g / mL) was supplied over 1 minute and held for 10 minutes. Then, the remaining monomer emulsion was supplied to the reactor over 60 minutes. Next, the remaining APS solution (2 to 4 g) was supplied to the reactor and held for 1 hour. The temperature was raised to 85°C to 90°C and held for 3 hours.

[0079] The dimensions of the resin particles were analyzed using Malvern Nano-ZS. The following parameters were used: D 50 =67nm, and D 95 A peak with a wavelength of 98 nm and a peak width of 31 nm was observed. Example 3

[0080] The process of Example 2 was modified and repeated as follows: 9.1 g of monomer emulsion was supplied, held for 1 to 5 minutes, then 2 to 4 g of APS solution was supplied over 1 minute, and held for 10 minutes. The remaining APS solution (10 g) was added while the remaining monomer emulsion was being supplied. Experiments were conducted in which the remaining APS solution was added intermittently or continuously along with the remaining monomer emulsion. Example 4

[0081] The process of Example 2 was repeated with the following modifications. The monomer emulsion contained the following components: 40 g of methyl methacrylate, 33 g of butyl acrylate, 6 g of methacrylic acid, 1.0 g of styrene sulfonic acid, 1.2 g of 1-dodecanethiol (DDT), 0.24 g of PEGDA 250, 1.36 g of Hitenol BC 1025, and 32 g of deionized water. Example 5 The process of Example 2 was repeated with the following modifications. The monomer emulsion contained the following components: 41 g methyl methacrylate, 25 g butyl acrylate, 6 g methacrylic acid, 1.0 g styrene sulfonic acid, 1.2 g 1-dodecanethiol (DDT), 0.24 g PEGDA 250, 1.36 g Hitenol BC 1025, 6 g polyethylene glycol methacrylate 750, and 32 g deionized water. The addition of hydrophilic polyethylene glycol methacrylate improved the freeze-thaw stability of the latex compared to Examples 1 and 2 (where precipitation was observed) (no precipitation was observed after three freeze-thaw cycles).

[0082] 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.”

[0083] All numerical values ​​of parameters in this disclosure are preceded by the term “approximately,” which means approximate. This includes variations inherent in the measurement of the relevant parameters as will be 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.

[0084] 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 have been 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.

Claims

1. 1. A method for forming a latex, comprising: (a) adding a first portion of a monomer emulsion comprising water, a monomer, an acidic monomer, a multifunctional monomer, and a first reactive surfactant to a reactive surfactant solution comprising water and a second reactive surfactant to form a reaction mixture, the reactive surfactant solution comprising no monomers other than the second reactive surfactant; (b) adding a first portion of an initiator solution to the reaction mixture such that monomers undergo a polymerization reaction to form resin seeds in the reaction mixture; (c) adding a second portion of the monomer emulsion to the reaction mixture containing the resin seeds; (d) adding a second portion of the initiator solution to the reaction mixture of step (b) or the reaction mixture of step (c) to form a latex containing resin particles; A method comprising:

2. The method of claim 1 , wherein the reactive surfactant solution is free of the initiator.

3. The method of claim 1 , wherein step (d) occurs after step (c).

4. 10. The method of claim 1 , wherein the addition of the second portion of the initiator solution occurs during the addition of the second portion of the monomer emulsion.

5. The method of claim 1, wherein the monomer emulsion comprises styrene and an alkyl acrylate in a weight ratio of styrene to alkyl acrylate of about 10:1 to about 1:

1.

6. The method of claim 1 , wherein the monomer emulsion is styrene-free.

7. The method of claim 1 , wherein the monomer emulsion comprises two different alkyl acrylates.

8. 8. The method of claim 7, wherein the two different alkyl acrylates are methyl (meth)acrylate and butyl (meth)acrylate present in a weight ratio of about 5:1 to about 1:5 (methyl (meth)acrylate) to (butyl (meth)acrylate).

9. The method of claim 1 , wherein the monomer emulsion is surfactant-free and the reactive surfactant solution is surfactant-free.

10. 10. The method of claim 1, wherein the monomer emulsion comprises styrene, an alkyl acrylate, methacrylic acid, a sulfonic acid monomer, poly(ethylene glycol) diacrylate, and an anionic ether sulfate reactive surfactant.

11. The method of claim 10, wherein the sulfonic acid monomer is styrene sulfonic acid.

12. 10. The method of claim 1, wherein the monomer emulsion comprises two different alkyl acrylates, methacrylic acid, a sulfonic acid monomer, poly(ethylene glycol) diacrylate, and an anionic ether sulfate reactive surfactant.

13. The method of claim 12, wherein the sulfonic acid monomer is styrene sulfonic acid.

14. The method of claim 12 , wherein the monomer emulsion further comprises a hydrophilic monomer.

15. The method of claim 14 , wherein the hydrophilic monomer is poly(ethylene glycol) methacrylate.

16. The method of claim 12, wherein the two different alkyl acrylates are methyl (meth)acrylate and butyl (meth)acrylate.

17. The method of claim 12, wherein the monomer emulsion is styrene-free.

18. The resin particles have a D of about 100 nm or less. 50 Particle size, D less than about 150 nm 95 The method of claim 1 , wherein the particles have a particle size and width of about 45 nm or less.

19. The resin particles have a D of about 75 nm or less. 50 Particle size, D less than about 100 nm 95 20. The method of claim 18, wherein the particles have a particle size and width of about 35 nm or less.