Aqueous ink and printed matter

Abstract

To provide an aqueous ink that employs biomass-derived material but enables recording of an image having gloss comparable to or exceeding that of an image recorded with a conventional ink prepared substantially without use of biomass-derived material, and a printed matter obtained using the aqueous ink.SOLUTION: An aqueous ink contains a colorant and a resin containing a unit derived from at least one selected from the group consisting of biomass-derived (meth)acrylic acid esters and biomass-derived (meth)acrylic acid, and a printed matter includes an image formed with the aqueous ink.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to water-based inks and printed matter. [Background technology]

[0002] In recent years, inkjet recording methods have been widely used as photographic printing methods because they are capable of recording high-resolution images and easily produce multicolor images. Furthermore, photographic printing methods are required to be capable of recording images with excellent gloss. To meet this requirement, inks containing a resin as a binder and inks containing a pigment dispersion using an alkali-soluble resin as a dispersant are used.

[0003] Furthermore, in response to recent concerns about the depletion of fossil resources and efforts to prevent global warming, the use of renewable biomass-derived materials is being recommended, and inks with a high biomass content, which contain resins synthesized using biomass-derived materials, have been proposed (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-8569 Summary of the Invention [Problem to be solved by the invention]

[0005] Therefore, an object of the present invention is to provide an aqueous ink that uses a biomass-derived material but is capable of recording images having glossiness equal to or greater than that of images recorded with conventional inks prepared substantially without using biomass-derived materials. Another object of the present invention is to provide printed materials obtained using this aqueous ink. [Means for solving the problem]

[0006] That is, according to the present invention, there is provided an aqueous ink containing a colorant and a resin including a unit derived from at least one selected from the group consisting of a biomass-derived (meth)acrylic acid ester and a biomass-derived (meth)acrylic acid. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide an aqueous ink that uses a biomass-derived material but is capable of recording an image having glossiness equal to or greater than that of an image recorded with a conventional ink prepared substantially without using a biomass-derived material. Furthermore, according to the present invention, it is possible to provide a printed matter obtained using this aqueous ink. DETAILED DESCRIPTION OF THE INVENTION

[0008] The present invention will be described in further detail below with reference to preferred embodiments. In the present invention, when the compound is a salt, the salt is present in the ink as dissociated ions, but for convenience it will be expressed as "containing a salt." Inkjet ink may also be referred to simply as "ink." Physical property values ​​are values ​​at room temperature (25°C) unless otherwise specified. The terms "(meth)acrylic acid" and "(meth)acrylate" refer to "acrylic acid, methacrylic acid" and "acrylate, methacrylate," respectively.

[0009] The present inventors investigated the composition of an ink that uses biomass-derived materials but can print images with glossiness equal to or greater than that of images printed with conventional inks prepared substantially without using biomass-derived materials. Specifically, they compared the characteristics of images (i) and (ii) shown below. As a result, they found that there was no significant difference in the characteristics of the two, leading to the present invention. Therefore, the technology described herein can contribute to the realization of a sustainable society, such as a decarbonized / recycling-based society. (i) An image recorded with an ink containing a resin including a unit derived from at least one selected from the group consisting of a biomass-derived (meth)acrylic acid ester and a biomass-derived (meth)acrylic acid. (ii) An image recorded with an ink containing a resin containing a unit derived from at least one selected from the group consisting of a (meth)acrylic acid ester derived from petroleum resources and a (meth)acrylic acid derived from biomass.

[0010] <Water-based ink> The ink of the present invention is a water-based ink suitable for inkjet printing, which contains a colorant and a resin including a unit derived from at least one selected from the group consisting of a biomass-derived (meth)acrylic acid ester and a biomass-derived (meth)acrylic acid. The ink of the present invention is described in detail below.

[0011] (resin) The ink contains a resin containing a unit derived from at least one selected from the group consisting of a biomass-derived (meth)acrylic acid ester and a biomass-derived (meth)acrylic acid. The content (mass %) of the resin in the ink is preferably 3.0% to 20.0% by mass, and more preferably 4.5% to 10.0% by mass, based on the total mass of the ink.

[0012] In the resin, the total content (% by mass) of units derived from biomass-derived (meth)acrylic acid esters and units derived from biomass-derived (meth)acrylic acid is preferably 20% by mass or more, based on the total mass of the resin. It is more preferably 15% by mass or more and 50% by mass or less. By using a resin in which the total content of the biomass-derived units falls within the above range, the glossiness of the image can be further improved. Furthermore, the resin is preferably a resin containing units derived from (meth)acrylic acid and having carboxylic acid groups in its molecule, with at least a portion of the carboxylic acid groups being neutralized with an alkali.

[0013] The present inventors prepared ink (i) and ink (ii) shown below. Then, they compared the glossiness of images recorded with these inks. As a result, it was found that ink (i) can record images with equal or higher glossiness even though it contains less of the above unit. The carbon atoms of biomass-derived (meth)acrylic acid ester and (meth)acrylic acid are unstable radioactive carbon atoms. 14 C, so it is a stable carbon atom 12 It is thought that resins containing units derived from biomass-derived (meth)acrylic acid esters or (meth)acrylic acid have a higher adsorption power to pigments, further improving the gloss of images. (i) an ink containing a resin having a total content of units derived from biomass-derived (meth)acrylic acid esters and units derived from biomass-derived (meth)acrylic acid of 20% by mass or more; (ii) Ink containing a resin with a total content of units derived from petroleum-derived (meth)acrylic acid esters and units derived from petroleum-derived (meth)acrylic acid of 20% by mass or more

[0014] Biomass-derived (meth)acrylic acid esters and (meth)acrylic acid can be produced according to known methods using biomass as a raw material. For example, biomass-derived (meth)acrylic acid esters and (meth)acrylic acid can be obtained by deoxygenating biomass-derived cinnamic acid. Biomass-derived (meth)acrylic acid esters and (meth)acrylic acid can also be obtained by using biomass-derived benzene and ethylene. Biomass-derived benzene and ethylene can be produced by cracking bionaphtha obtained from vegetable waste oil or animal waste oil. Benzene and ethylene can also be produced from bioethanol. Furthermore, benzene and ethylene may be produced using a mass balance approach, such as cracking a mixture of bionaphtha and petroleum-derived naphtha.

[0015] The biomass-derived (meth)acrylic acid ester is preferably an ester of (meth)acrylic acid and an alcohol having 1 to 22 carbon atoms. If the alcohol has 23 or more carbon atoms, the molecular size of the (meth)acrylic acid ester increases, which may result in non-uniform distribution of the resin within the image and a decrease in the effect of improving the gloss of the image.

[0016] The biomass-derived (meth)acrylic acid ester is preferably at least one selected from the group consisting of n-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, and n-butyl methacrylate. Use of these (meth)acrylic acid esters makes it easier to achieve a more uniform distribution of the resin in the image, thereby further improving the gloss of the image.

[0017] The biomass-derived (meth)acrylic acid ester may be any (meth)acrylic acid ester other than the above (meth)acrylic acid esters. Examples of other acrylic acid esters include ethyl acrylate, isobutyl acrylate, 1-methylheptyl acrylate, n-heptyl acrylate, tetrahydrofurfuryl acrylate, lauryl acrylate, isobornyl acrylate, tridecyl acrylate, docosyl acrylate, stearyl acrylate, n-octyl acrylate, and isoamyl acrylate.

[0018] Other methacrylic acid esters include isobutyl methacrylate, 1-methylheptyl methacrylate, n-heptyl methacrylate, tetrahydrofurfuryl methacrylate, lauryl methacrylate, isobornyl methacrylate, tridecyl methacrylate, docosyl methacrylate, stearyl methacrylate, dodecyl methacrylate, ethylene glycol dimethacrylate, and cyclohexyl methacrylate.

[0019] The acid value of the resin is preferably 10 mgKOH / g or more and 200 mgKOH / g or less. By using a resin with an acid value within the above range, it is possible to record an image with improved gloss. If the acid value of the resin is less than 10 mgKOH / g, the distribution of the resin within the image tends to be uneven, and the effect of improving gloss may be slightly reduced. On the other hand, if the acid value of the resin is more than 200 mgKOH / g, the amount of hydration increases, making it difficult to dry. As a result, the distribution of the resin within the image tends to be uneven, and the effect of improving gloss may be slightly reduced.

[0020] The weight-average molecular weight of the resin is preferably 4,000 or more and 20,000 or less. By using a resin with a weight-average molecular weight within the above range, images with improved gloss can be recorded. If the weight-average molecular weight of the resin is less than 4,000, the resin molecules may not easily entangle with each other within the image. This can lead to uneven distribution of the resin within the image, slightly reducing the gloss-improving effect. On the other hand, if the weight-average molecular weight of the resin is more than 20,000, the viscosity of the ink may increase excessively, requiring a long time for film formation. This can reduce the gloss-improving effect of the image immediately after recording.

[0021] The resin may be either a water-soluble resin or resin particles. In the present invention, "resin particles" refers to a resin that exists in a state in which it is not dissolved in the aqueous medium that constitutes the ink. More specifically, it refers to a resin that can exist in the aqueous medium in a state in which it has formed particles whose particle diameter can be measured by dynamic light scattering. On the other hand, "water-soluble resin" refers to a resin that exists in a state in which it has dissolved in the aqueous medium that constitutes the ink. More specifically, it refers to a resin that can exist in the aqueous medium in a state in which it has not formed particles whose particle diameter can be measured by dynamic light scattering. Resin particles, when expressed as the counterpart of "water-soluble resin", are called "water-dispersible resin (water-insoluble resin)".

[0022] Resin particles may be in the form of surfactant-emulsified or dispersed resin particles, self-dispersed resin particles, or core-shell resin particles. Whether a resin is a "resin particle" can be determined according to the following method. First, a liquid containing the resin to be determined is diluted with pure water to prepare a sample with a resin content of approximately 1.0%. Then, when the particle size of the resin in the sample is measured by dynamic light scattering, if particles having the particle size are measured, the resin is determined to be a "resin particle" (i.e., a "water-dispersible resin"). On the other hand, if particles having the particle size are not measured, the resin is determined not to be a "resin particle" (i.e., a "water-soluble resin"). The measurement conditions can be, for example, Set Zero: 30 seconds, number of measurements: 10, measurement time: 120 seconds, shape: spherical, refractive index: 1.5, and density: 1.0. As the particle size distribution measuring device, a particle size analyzer using dynamic light scattering (for example, the trade name "Nanotrac WAVEII-Q" manufactured by Microtrac Bell) can be used. Of course, the particle size distribution measuring device and measurement conditions to be used are not limited to those described above.

[0023] The water-soluble resin can be used as a dispersant for dispersing the pigment. The acid value of the water-soluble resin is preferably 100 mgKOH / g or more and 180 mgKOH / g or less. Using a water-soluble resin with an acid value within the above range as a dispersant can further improve dispersion stability and ejection performance. If the acid value of the water-soluble resin is less than 100 mgKOH / g, it will have a strong adsorption force to the pigment, making it somewhat difficult to redisperse the ink after drying. This may result in a slight decrease in ink ejection performance. On the other hand, if the acid value of the water-soluble resin is greater than 180 mgKOH / g, it may be more likely to peel from the pigment, resulting in a slight decrease in dispersion stability. The acid value of the water-soluble resin can be controlled by adjusting the ratio of the carboxylic acid group-containing monomer used in synthesizing the resin.

[0024] The weight-average molecular weight of the water-soluble resin is preferably 5,000 or more and 12,000 or less. If the weight-average molecular weight of the water-soluble resin is less than 5,000, its function as a dispersant may be slightly reduced. On the other hand, if the weight-average molecular weight of the water-soluble resin is more than 12,000, its adsorption to the pigment may be so strong that the ink ejection performance may be slightly reduced.

[0025] The preferred ranges of the acid value and the weight-average molecular weight of the resin are both ranges when a biomass-derived (meth)acrylic acid ester or (meth)acrylic acid is used. These ranges differ from the ranges when a petroleum-derived (meth)acrylic acid ester or (meth)acrylic acid is used. The reason for the difference in the preferred ranges between the two is not entirely clear, but as mentioned above, it is presumed that the difference in carbon atoms has an effect.

[0026] When the resin forms resin particles, the cumulative 50% particle diameter (D 50 ) (hereinafter also referred to as "average particle diameter") is preferably 50 nm or more and 250 nm or less. If the average particle diameter of the resin particles is less than 50 nm, the specific surface area increases, which increases the number of interfaces when redispersing dried ink. This may result in a decrease in the redispersibility of the ink. On the other hand, if the average particle diameter of the resin particles exceeds 250 nm, unevenness due to the resin particles is likely to form on the image surface, which may reduce the effect of improving gloss.

[0027] The cumulative 50% particle size (D 50 ) is the cumulative 90% particle diameter (D 90 ) is preferably 0.6 times or more and 0.8 times or less. If the ratio is less than 0.6 times, the particle size distribution will be broad, which may result in irregular placement of the resin particles in the image and a decrease in the effect of improving gloss.

[0028] The weight-average molecular weight of the resin (water-insoluble resin) that forms the resin particles is preferably 1,000,000 or less. If the weight-average molecular weight of the water-insoluble resin exceeds 1,000,000, the resin particles tend to settle and coalesce in the ink, increasing their particle size, which may reduce the effect of improving the storage stability of the ink.

[0029] The preferred range of the weight average molecular weight is different between a resin containing a unit derived from a biomass-derived (meth)acrylic acid ester or (meth)acrylic acid and a resin containing a unit derived from a petroleum resource-derived (meth)acrylic acid ester. The molecular chain of the resin containing a unit derived from a biomass-derived (meth)acrylic acid ester contains a carbon-14 ( 14 C). For this reason, resin particles formed from a resin containing units derived from a biomass-derived (meth)acrylic acid ester or the like have a higher specific gravity than resin particles formed from a resin containing units derived from a petroleum-derived (meth)acrylic acid ester or the like. This is thought to make them more susceptible to settling. Therefore, from the perspective of further improving the storage stability of the ink, the following can be considered: That is, the preferred weight-average molecular weight of a resin containing units derived from a biomass-derived (meth)acrylic acid ester or the like is smaller than the weight-average molecular weight of a resin containing units derived from a fossil-derived (meth)acrylic acid ester or the like.

[0030] Since the resin particles are used as a constituent of the ink, they are preferably dispersed in an aqueous medium in the form of a dispersion. The aqueous medium is primarily composed of water, such as deionized water, ion-exchanged water, or distilled water, and may further contain a water-soluble organic solvent as needed. The water content (mass %) in the aqueous medium is preferably 50 mass % or more based on the total mass of the aqueous medium, and it is also preferable to use a liquid medium (i.e., water) that does not substantially contain a water-soluble organic solvent.

[0031] Examples of methods for forming resin particles by granulating a resin include emulsion polymerization, mini-emulsion polymerization, seed polymerization, dispersion, and phase inversion (emulsion) methods. Dispersion methods include the following methods (1) and (2). (1) A method in which a resin is dissolved in an organic solvent and the resulting solution is added to an aqueous medium to disperse the resin. (2) A method in which a resin is added to an organic solvent, and then an aqueous medium is added and mixed to disperse the resin.

[0032] The phase inversion (emulsification) method includes a method in which an aqueous medium is added to a solution obtained by dissolving a resin in an organic solvent, and the resin is precipitated in the form of particles during the process of phase inversion from a solvent system to an aqueous system. In either method, it is preferable to use a known disperser to granulate the resin while applying an appropriate shear force, and adjust the particle size of the resulting resin particles. Since the particle size of the resulting resin particles can be adjusted with precision, it is preferable to produce resin particles by emulsion polymerization.

[0033] The resin particles may be dyed with a coloring material. Examples of methods for dyeing the resin particles include a method of forming resin particles by polymerizing a monomer mixture in which a dye is dissolved, and a method of adding a dye to resin particles and heating the particles. Among these, the method of adding a dye to resin particles and heating the particles is preferred because it can be used with a wider variety of dyes.

[0034] When the colorant is a pigment, a resin is preferably used as a dispersant for dispersing the pigment. The resin used as a dispersant is preferably a copolymer containing units derived from biomass-derived (meth)acrylic acid. Furthermore, the resin used as a dispersant is more preferably a copolymer of biomass-derived styrene, biomass-derived (meth)acrylic acid ester, and biomass-derived acrylic acid or methacrylic acid. It is preferable that at least a portion of the carboxylic acid groups in these copolymers are neutralized with an alkali. By using such a copolymer (resin) as a dispersant, it is possible to prepare an aqueous pigment dispersion or ink with excellent dispersibility, which is less susceptible to pigment aggregation and precipitation. The copolymer may be in the form of a random copolymer, a block copolymer, or a graft copolymer. Furthermore, when a resin is used as a dispersant, the content (mass%) of the dispersant is preferably 0.1 to 0.5 times the mass ratio of the content (mass%) of the pigment.

[0035] In the resin used as a dispersant, the content (mass%) of units derived from acrylic acid or methacrylic acid relative to the content (mass%) of units derived from biomass-derived styrene is preferably 0.1 to 1.0 times, in mass ratio, and more preferably 0.2 to 0.4 times. By achieving this mass ratio, even when the ink is continuously ejected, ejection defects due to kogation and deposits adhering within the ink flow path and near the ejection orifice are less likely to occur, thereby improving the ejection stability of the ink. For this reason, resins with the above mass ratio are suitable as dispersants for inkjet inks, particularly thermal-type inkjet inks.

[0036] The pigment dispersion can be prepared by a dispersion method using a dispersion device or a production method in which dispersion conditions such as dispersion time, peripheral speed, and, if necessary, the type and particle size of the media used are appropriately set. Examples of the dispersion device include a roll mill, a bead mill, a paint shaker, a sand mill, an agitator mill, a nanomizer, a homogenizer, a microfluidizer, an ultimizer, and an ultrasonic disperser.

[0037] (colorant) The ink contains a colorant. The content (mass %) of the colorant in the ink is preferably 0.05% by mass or more and 15.0% by mass or less, and more preferably 0.1% by mass or more and 10.0% by mass or less, based on the total mass of the ink.

[0038] Dyes and pigments can be used as colorants. Examples of dyes include direct dyes, acid dyes, basic dyes, disperse dyes, food dyes, and oil-based dyes. Among these, it is preferable to use a dye having an anionic group. Specific examples of dye skeletons include xanthene, azine, azole, thiazole, azo, diarylmethane, triarylmethane, acridine, coumarin, methine, triphenylmethane, phthalocyanine, azaphthalocyanine, and anthrapyridone. When using resin particles dyed with a dye (dyed resin particles), it is preferable to use a basic dye, and it is more preferable to use a dye having a xanthene skeleton. Among these, CI Basic Red 1 (1:1), CI Basic Violet 11 (11:1), CI Basic Yellow 40, and the like are preferred due to their excellent color development.

[0039] Examples of pigments include inorganic pigments such as carbon black and titanium oxide; and organic pigments such as azo, phthalocyanine, quinacridone, isoindolinone, imidazolone, diketopyrrolopyrrole, and dioxazine. Pigment dispersion methods include resin-dispersed pigments, which use a resin as a dispersant, and self-dispersed pigments, in which hydrophilic groups are bonded to the pigment particle surface. Also usable are resin-bonded pigments, in which organic groups containing a resin are chemically bonded to the pigment particle surface, and microencapsulated pigments, in which the pigment particle surface is coated with a resin or the like.

[0040] It is preferable to use a coloring material derived from biomass as the coloring material. Conventional coloring materials derived from petroleum resources can also be used. However, when biomass-derived carbon black is used as the coloring material, the dispersion stability and ejection properties of the ink may be easily reduced. Biomass-derived carbon black contains radioactive carbon atoms that are unstable as atoms. 14 Because it contains C, it is thought that this affects the adsorption properties of the resin containing units derived from biomass-derived monomers, making the ink's dispersion stability and ejection properties more likely to decrease.

[0041] (aqueous medium) The ink is an aqueous ink containing at least water as the aqueous medium. The ink may contain water or an aqueous medium that is a mixed solvent of water and a water-soluble organic solvent. Deionized water or ion-exchanged water is preferably used as the water. The water content (mass %) in the ink is preferably 50.0% to 95.0% by mass, based on the total mass of the ink. Furthermore, the water-soluble organic solvent content (mass %) in the ink is preferably 3.0% to 50.0% by mass, based on the total mass of the ink.

[0042] Examples of the water-soluble organic solvent include glycol ethers, alkanols having 1 to 4 carbon atoms, carboxylic acid amides, ketones or ketoalcohols, cyclic ethers, glycols, polyethylene glycols, acetylene glycol derivatives, polyhydric alcohols, heterocycles, and sulfur-containing compounds.

[0043] Examples of glycol ethers include diethylene glycol monomethyl (or ethyl) ether and triethylene glycol monoethyl (or butyl) ether. Examples of alkanols having 1 to 4 carbon atoms include methanol, ethanol, propanol, isopropanol, n-butanol, sec-butanol, isobutanol, and t-butanol. Examples of carboxylic acid amides include N,N-dimethylformamide and N,N-dimethylacetamide. Examples of ketones or ketoalcohols include acetone, methyl ethyl ketone, and 2-methyl-2-hydroxypentan-4-one. Examples of cyclic ethers include tetrahydrofuran and dioxane.

[0044] Examples of glycols include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, and butylene glycol. Examples of polyethylene glycols include those having a number-average molecular weight of 200 to 2,000, more specifically, those having number-average molecular weights of 200, 400, 600, 1,000, and 2,000. Examples of polyhydric alcohols include glycerin, 3-butanediol, 1,5-pentanediol, 1,6-hexanediol, and 1,2,6-hexanetriol. Examples of heterocyclic rings include 2-pyrrolidone, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, and N-methylmorpholine. Examples of sulfur-containing compounds include thiodiglycol and dimethyl sulfoxide.

[0045] (Other ingredients) In addition to the above components, the ink may contain, if necessary, organic compounds that are solid at room temperature, such as trimethylolethane and trimethylolpropane, and nitrogen-containing compounds, such as urea and ethyleneurea. In addition to the above components, the ink may further contain, if necessary, various additives, such as surfactants, pH adjusters, rust inhibitors, preservatives, antifungal agents, antioxidants, reduction inhibitors, evaporation accelerators, and chelating agents.

[0046] <Printed material> The printed matter of the present invention includes a substrate and an image formed on the surface of the substrate. The image is formed using the aqueous ink described above. Because the printed matter of the present invention contains a biomass-derived material, it is an environmentally friendly printed matter from the viewpoint of carbon neutrality.

[0047] The substrate can be a recording medium used in a recording method such as an inkjet recording method. Any recording medium can be used and can be selected depending on the intended use of the recorded image. Examples of the recording medium include permeable paper, such as plain paper or a recording medium having a coating layer. For example, plain paper, which is suitable for obtaining images such as business documents, can be used. Furthermore, glossy paper, which is suitable for obtaining images with a glossy appearance similar to photographic quality, and art paper, which makes use of the texture of the substrate (such as matte, drawing paper, canvas, or Japanese paper), can be used to express paintings, photographs, and graphic images according to preference. In particular, it is preferable to use a recording medium such as plain paper without a coating layer or a recording medium such as coated paper with a coating layer.

[0048] In addition, plastic films (recording media in which a plastic film is adhered to the recording surface of a substrate, or recording media in which an organic resin coating layer is provided on the recording surface of a substrate containing cellulose pulp) can be used as low to non-absorbent recording media. [Example]

[0049] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples as long as the gist of the invention is not exceeded. The terms "parts" and "%" used to describe the amounts of components are based on mass unless otherwise specified.

[0050] <Methods for measuring physical properties> (average particle size of resin particles) Using a dynamic light scattering particle size analyzer, the average particle size of the resin particles (particle size at 50% of the cumulative volumetric particle size distribution) was measured under the following conditions: Set Zero: 30 seconds, number of measurements: 3, measurement time: 180 seconds, shape: spherical, refractive index: 1.59. The particle size analyzer used was the "UPA-EX150" (manufactured by Nikkiso).

[0051] (resin acid value) The acid value of the resin was measured according to the following method in accordance with JIS K 0070. (1) Accurately weigh 0.5 to 2.0 g of sample. The mass of the accurately weighed sample is defined as M (g). (2) Place the sample in a 50 mL beaker and add 25 mL of a mixture of tetrahydrofuran / ethanol (mass ratio = 2 / 1) to dissolve the sample. (3) Using a potentiometric titration device, titration is performed with a 0.1 mol / L ethanol solution of potassium hydroxide (KOH solution). As the potentiometric titration device, for example, an automatic titration device manufactured by Hiranuma Sangyo Co., Ltd. (product name "COM-2500") can be used. (4) The amount of KOH solution used in the titration is S (mL). At the same time, measure a blank and let the amount of KOH solution used be B (mL). (5) The acid value of the resin is calculated using the following formula (1): In the formula (1), f represents the factor of the KOH solution. Acid value of resin (mgKOH / g) = (SB) × f × 5.61 / M (1)

[0052] (weight average molecular weight of resin) The weight average molecular weight of the resin was measured by gel permeation chromatography (GPC) under the following conditions: Apparatus: Alliance GPC 2695 (Waters) Column: Shodex KF-806M 4-column (Showa Denko) ·Mobile phase: THF (special grade) ·Flow rate: 1.0mL / min Oven temperature: 40.0℃ Sample solution injection volume: 0.1 mL Detector: RI (refractive index) Polystyrene standards: PS-1 and PS-2 (manufactured by Polymer Laboratories, molecular weights: 7,500,000, 2,560,000, 841,700, 377,400, 320,000, 210,500, 148,000, 96,000, 59,500, 50,400, 28,500, 20,650, 10,850, 5,460, 2,930, 1,300, 580, 17 types).

[0053] <Preparation of water-soluble resin> (Water-soluble resin 1~44) A flask equipped with a stirrer, nitrogen inlet tube, reflux condenser, and thermometer was charged with 200.0 parts of isopropanol, and the temperature was raised to 85°C under a nitrogen atmosphere while stirring. A mixture of monomers and a polymerization initiator, the types and amounts (units: parts) shown in Tables 1-1 to 1-4, were added dropwise to the flask over 2 hours while maintaining the internal temperature at 80°C. The mixture was stirred at 80°C for 4 hours to form a resin. After adding 0.9 equivalents of potassium hydroxide relative to the acid value of the resin and an appropriate amount of ion-exchanged water, the isopropanol was removed under reduced pressure to obtain a liquid containing a water-soluble resin with a resin content of 20.0%. All resins were dissolved in the resulting liquid, and no resin particles were formed. The acid values ​​and weight-average molecular weights of water-soluble resins 1 to 44 are shown in Tables 1-1 to 1-4. The abbreviations in Tables 1-1 to 1-4 are defined below. In Tables 1-1 to 1-4, (B) and (P) attached to the monomers mean "derived from biomass" and "derived from petroleum resources," respectively. AA: Acrylic acid ·MAA: methacrylic acid BA: n-butyl acrylate 2EHA: 2-ethylhexyl acrylate MMA: Methyl methacrylate EMA: Ethyl methacrylate BMA: Butyl methacrylate αMSt: α-methylstyrene TDA: Docosyl acrylate TCA: Tricosyl acrylate AN: Acrylonitrile St: Styrene BzMA: Benzyl acrylate V-59: 2,2'-azobis(2-methylbutyronitrile) (Fujifilm Wako Pure Chemical Industries, Ltd.)

[0054] The biomass-derived acrylic acid was obtained by two-step oxidation of biomass-derived propylene, and the biomass-derived methacrylic acid was obtained by adding hydrogen cyanide to biomass-derived acetone to form acetone cyanohydrin, which was then dehydrated and hydrolyzed with sulfuric acid.

[0055] The biomass-derived n-butyl acrylate, 2-ethylhexyl acrylate, tridecyl acrylate, docosyl acrylate, and tricosyl acrylate were synthesized using biomass-derived acrylic acid. Specifically, the products were obtained by purifying esters of biomass-derived acrylic acid with butanol, 2-ethylhexanol, 1-docosanol, and 1-tricosanol. The biomass-derived methyl methacrylate, ethyl methacrylate, and butyl methacrylate were synthesized using biomass-derived methacrylic acid. Specifically, the products were obtained by purifying esters of biomass-derived methacrylic acid with methanol, ethanol, and butanol.

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[0060] <Preparation of resin particles> (Resin particles 1-16, 18-24) The types and amounts (units: parts) of monomers, emulsifiers, and 150.0 parts of ion-exchanged water shown in Tables 2-1 and 2-2 were mixed using a homogenizer (product name "T50D Ultra Turrax," manufactured by IKA) to obtain a mixture. 50.0 parts of the mixture was placed in a flask equipped with a stirrer, nitrogen inlet tube, reflux condenser, and thermometer, and the temperature was raised to 70°C while stirring under a nitrogen atmosphere. The remainder of the mixture and a liquid obtained by dissolving 1.0 part of potassium persulfate in 20.0 parts of ion-exchanged water were added dropwise over 2 hours. After heating to 80°C, the mixture was stirred for 2 hours to allow the reaction to proceed, yielding a dispersion. The pH of the resulting dispersion was adjusted to 8.5 by adding 1 mol / L aqueous potassium hydroxide solution, and an appropriate amount of ion-exchanged water was added to obtain aqueous dispersions of resin particles 1-16 and 18-24, each with a resin particle content of 20.0%. The average particle diameters, resin acid values, and weight-average molecular weights of resin particles 1 to 16 and 18 to 24 are shown in Tables 2-1 and 2-2. The meanings of the abbreviations in Tables 2-1 and 2-2 are as follows. In Tables 2-1 and 2-2, (B) and (P) attached to the monomers mean "biomass-derived" and "petroleum-derived," respectively. ·MAA: methacrylic acid BA: n-butyl acrylate MMA: Methyl methacrylate EMA: Ethyl methacrylate BMA: Butyl methacrylate BzMA: Benzyl methacrylate NS-5S: Emulsifier (product name "Eleminol NS-5S", manufactured by Sanyo Chemical Industries, Ltd.)

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[0062] TIFF2025185929000006.tif130170

[0063] (Resin particles 17, 25) A reaction vessel equipped with a stirrer was placed in a hot water bath. 1,178 parts of water was placed in the reaction vessel, and the internal temperature was maintained at 70°C. 466 parts of a monomer mixture was prepared by mixing the types and amounts (units: parts) shown in Table 3. 1.9 parts of potassium persulfate and 659 parts of water were mixed to prepare an aqueous solution of a polymerization initiator. The monomer mixture and the aqueous solution of the polymerization initiator were added dropwise in parallel to the reaction vessel over 60 minutes. After the addition was completed, the mixture was stirred for an additional 30 minutes to react and form resin particles. An appropriate amount of an 8 mol / L aqueous potassium hydroxide solution was added to the reaction vessel to adjust the pH of the liquid to 8.5.

[0064] 29 parts of dye (powder form) of the type and breakdown (%) shown in Table 3 were added. The temperature was raised to 80°C and the mixture was stirred for 2 hours to allow the dye to adhere to the resin particles. An appropriate amount of 8 mol / L potassium hydroxide aqueous solution was added to the reaction vessel to adjust the pH of the liquid to 8.5. An appropriate amount of water was further added to obtain aqueous dispersions of resin particles 17 and 25 with a resin particle content of 20.0%. The average particle size and weight-average molecular weight of resin particles 17 and 25 are shown in Table 3. The meanings of the abbreviations in Table 3 are as follows. In Table 3, (B) and (P) attached to the monomers mean "biomass-derived" and "petroleum-derived," respectively. ·MAA: methacrylic acid St: Styrene BzMA: Benzyl methacrylate AN: Acrylonitrile SR-10: Emulsifier, α-sulfo-ω-(1-alkoxymethyl-2-(2-propenyloxy)ethoxy)-poly(oxy-1,2-ethanediyl)ammonium salt (trade name "ADEKA REASOAP SR-10", manufactured by ADEKA) BR1: CI Basic Red 1 BV11: CI Basic Violet 11

[0065] TIFF2025185929000007.tif102170

[0066] <Preparation of pigment dispersion> (Pigment dispersion 1) 37.5 parts of a liquid containing water-soluble resin 1, 15 parts (solids) of CI Pigment Blue 15:3, and 47.5 parts of ion-exchanged water were mixed. A batch-type vertical sand mill (manufactured by Imex) filled with 85 parts of 0.3 mm diameter zirconia beads was used to carry out a dispersion process for 3 hours with water cooling. The mixture was centrifuged to remove coarse particles, and then pressure-filtered through a 3.0 μm pore-size microfilter (manufactured by Fujifilm) to obtain pigment dispersion 1, which had a pigment content of 10.0% and a water-soluble resin content of 3.0%.

[0067] (Pigment dispersions 2-27, 29-52) Pigment dispersions 2 to 27 and 29 to 52 were obtained in the same manner as the above-described pigment dispersion 1, except that the types of water-soluble resins and pigments shown in Table 4 were used and the amounts of the water-soluble resins and pigments were adjusted to the contents shown in Table 4. The meanings of the abbreviations in Table 4 are as follows: PB15:3: CI Pigment Blue 15:3 PR122: CI Pigment Red 122 PY74: CI Pigment Yellow 74

[0068] (Pigment Dispersion 28) Using a homogenizer, 300 parts of untreated rutile-type titanium dioxide (trade name "TITAN IX JR," manufactured by Teika) and 700 parts of pure water were mixed to obtain a mixture. The resulting mixture was heated to 90°C while stirring, and potassium hydroxide was added to adjust the pH to 10.5. After adding sodium silicate, dilute sulfuric acid was added over approximately 1 hour to adjust the pH to 5.0, and the reaction was continued for approximately 1 hour. The mixture was heated to 90°C, and sodium aluminate was added in small amounts. During this process, dilute sulfuric acid was also used to maintain the pH at 6.0 to 8.0. After adding sodium aluminate, the reaction was continued for approximately 1 hour to obtain a dispersion. The resulting dispersion was cooled to 25°C and then purified by repeated centrifugation and redispersion in ion-exchanged water. The resulting mixture was then dried at 120°C to obtain titanium dioxide particles surface-treated with alumina.

[0069] 40.0 parts of the obtained titanium oxide particles, 1.2 parts of a nonionic surfactant (trade name "Acetylenol E60" manufactured by Kawaken Fine Chemicals), and 58.8 parts of ion-exchanged water were mixed and pre-dispersed using a homogenizer to obtain a mixture. The resulting mixture was placed in a paint shaker filled with 0.5 mm zirconia beads and fully dispersed at 25°C for 12 hours. After filtering to remove the zirconia beads, an appropriate amount of ion-exchanged water was added to obtain pigment dispersion 28 with a pigment content of 10.0%.

[0070] <Rating (1)> (dispersion stability) The prepared pigment dispersions were placed in sealed containers and stored in a thermostatic chamber at 70°C for 60 days before being removed. After cooling to room temperature, the average particle diameter (D 50 (nm), D 90 The particle diameter (nm) and the number of particles with a particle diameter of 0.5 μm or more and less than 5.0 μm were measured. The dispersion stability of the pigment in the pigment dispersion was then evaluated according to the following evaluation criteria. The results are shown in Table 4. A:D 50 Rate of change of (nm), D 90The rate of change in particle size (nm) and the rate of change in the number of particles with a particle size of 0.5 μm or more and less than 5.0 μm were both 5% or less. B:D 50 Rate of change of (nm), D 90 At least one of the rate of change in the particle diameter (nm) and the rate of change in the number of particles having a particle diameter of 0.5 μm or more and less than 5.0 μm exceeded 5%.

[0071] (Average particle size of pigment (D 50 (nm), D 90 (nm)) The pigment dispersion was diluted 10,000 times (by mass) with pure water, and the average particle diameter (D 50 (nm), D 90 (nm)) was measured under the following measurement conditions: [Measurement conditions] Setzero:30s Measurement time: 120 seconds Measurement count: 3 times Particle refractive index: 1.8 Solvent: Water Filter: Standard Sensitivity: Standard

[0072] (Method for measuring the number of particles with a particle diameter of 0.5 μm or more and less than 5.0 μm) The pigment dispersion was diluted 10,000 times (by mass) with pure water, and then the number of particles with a particle size of 0.5 μm or more and less than 5.0 μm was measured using a particle size distribution analyzer (product name "Accusixer780APS", manufactured by Particle Sizing System). The measurement conditions are as follows: [Measurement conditions] Measurement time: 60 seconds Number of channels: 128 ·Flow rate: 60mL / min Sample loop capacity: 1 mL First dilution ratio: 30 times Second stage dilution ratio: 40x

[0073] TIFF2025185929000008.tif187170

[0074] <Ink Preparation> (Ink 1) Ink 1 was prepared by mixing the components shown below, thoroughly stirring, and then filtering under pressure using a microfilter (manufactured by Fujifilm) with a pore size of 3.0 μm. ·Cabojet250C: 30.0 copies Liquid containing water-soluble resin 1: 22.5 parts Glycerin: 10.0 parts 1,2-Hexanediol: 5.0 parts Polyethylene glycol (number average molecular weight 1,000): 3.0 parts Acetylenol E100: 0.5 parts Proxel GXL(S): 0.2 parts Ion-exchanged water: The remaining amount (parts) that makes the total of all ingredients 100.0 parts

[0075] "Cabojet250C" is the trade name of a self-dispersing cyan pigment dispersion (manufactured by Cabot Japan, pigment concentration 10.0%). "Acetylenol E100" is the trade name of a nonionic acetylene glycol surfactant (manufactured by Kawaken Fine Chemicals). "Proxel GXL(S)" is the trade name of a preservative (manufactured by Arch Chemicals).

[0076] (Ink 2-69) Inks 2 to 69 were prepared in the same manner as Ink 1 above, except that the types of pigment dispersions and added resins (water-soluble resins, resin particles) shown in Tables 5-1 to 5-3 were used.

[0077] (Ink 70) The components shown below were mixed and thoroughly stirred, and then pressure filtered through a microfilter (manufactured by Fujifilm) with a pore size of 3.0 μm to prepare ink 70. Pigment dispersion 1:30.0 parts Liquid containing water-soluble resin 1: 15.0 parts Glycerin: 10.0 parts 1,2-Hexanediol: 5.0 parts Polyethylene glycol (number average molecular weight 1,000): 3.0 parts Acetylenol E100: 0.5 parts Proxel GXL(S): 0.2 parts Ion-exchanged water: 36.3 parts

[0078] "Acetylenol E100" is the trade name of a nonionic acetylene glycol surfactant (manufactured by Kawaken Fine Chemicals). "Proxel GXL(S)" is the trade name of a preservative (manufactured by Arch Chemicals).

[0079] (Ink 71~120) Inks 71 to 120 were prepared in the same manner as Ink 70 described above, except that the types of pigment dispersions and added resins (water-soluble resins, resin particles) shown in Tables 5-3 and 5-4 were used.

[0080] In Tables 5-1 to 5-4, the meanings of "Ratio1 (%)" and "Ratio2 (%)" are as follows: "Ratio 1 (%)": The total content (%) of units derived from biomass-derived (meth)acrylic acid ester, units derived from biomass-derived acrylic acid, and units derived from biomass-derived methacrylic acid, based on the total mass of the resin "Ratio2 (%)": Dispersant content (%) based on colorant (pigment)

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[0085] <Evaluation (2)> The following items were evaluated, and the results are shown in Table 6.

[0086] (reducing environmental impact) The ink was evaluated for its reduction in environmental impact according to the following evaluation criteria. ○: Uses a resin containing units derived from biomass-derived monomers, contributing to the reduction of greenhouse gas emissions. ×: Resin containing no units derived from biomass-derived monomers is used, and does not contribute to reducing greenhouse gas emissions.

[0087] (glossiness) Each ink was filled into an ink cartridge and inserted into an inkjet recording device (product name: "PIXUS iP3100" manufactured by Canon), which ejects ink from a recording head using thermal energy. In this example, a solid image recorded at a rate of one 5 pL ink droplet per droplet per 1 / 1,200-inch x 1 / 1,200-inch unit area was defined as 100% printing duty. Using the inkjet recording device, a 2 cm x 2 cm solid image (100% printing duty) was recorded on a recording medium (product name: "Canon Photo Paper Gloss Gold GL-101" manufactured by Canon). After drying the recorded image at 25°C for 24 hours, two fluorescent lamps spaced 10 cm apart were used as the observation light source, and the fluorescent lamp was projected from a distance of 2 m. The shape of the fluorescent lamp projected onto the image was visually confirmed at an illumination angle of 45° and an observation angle of 45°, and the glossiness of the image was evaluated according to the following evaluation criteria. A: Two fluorescent lights were clearly visible in the image. B: The edges of the two projected fluorescent lights were slightly blurred. C: I couldn't see the boundary between the two projected fluorescent lights.

[0088] (Discharge stability) Using the inkjet recording device described above, images were recorded on an A4-sized recording medium (PPC paper, product name "GF-500," manufactured by Canon). Specifically, two 19 cm x 26 cm solid images with a recording duty of 100% were recorded, followed by a 30-minute pause, followed by another two similar solid images. This procedure constituted one cycle. The recording conditions were a temperature of 23°C and a relative humidity of 55%. The ejection volume per droplet was within 28 ng ± 10% for black ink and 5.8 ng ± 10% for color ink. In this example, a solid image recorded under the following conditions (i) and (ii) is defined as having a recording duty of 100%. (i) In the case of black ink, the condition is that one drop of ink weighing approximately 28 ng is applied to a unit area of ​​1 / 600 inch x 1 / 600 inch. (ii) In the case of color ink, four drops of ink, each weighing approximately 5.8 ng, are applied to a unit area of ​​1 / 600 inch x 1 / 600 inch.

[0089] After repeating the above cycle 10 times, a nozzle check pattern was recorded on one sheet of the inkjet recording device and visually inspected. After recording, the recording head was removed and any deposits around the ejection ports were observed under a microscope. The ink ejection stability was then evaluated according to the following evaluation criteria. A: There was no adhesion around the nozzle, and the nozzle check pattern was not disturbed. B: There was a small amount of adhesion around the ejection port, and the nozzle check pattern was slightly disturbed, but still within the usable level.

[0090] TIFF2025185929000013.tif239170

[0091] The disclosure of this embodiment includes the following configurations. (Configuration 1) A water-based ink containing a colorant and a resin including a unit derived from at least one selected from the group consisting of a biomass-derived (meth)acrylic acid ester and a biomass-derived (meth)acrylic acid. (Configuration 2) The aqueous ink according to configuration 1, wherein the (meth)acrylic acid ester is an ester of (meth)acrylic acid and an alcohol having 1 to 22 carbon atoms. (Configuration 3) The aqueous ink according to Configuration 1 or 2, wherein the (meth)acrylic acid ester is at least one selected from the group consisting of n-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, and n-butyl methacrylate. (Configuration 4) The resin is a resin containing a carboxylic acid group in its molecule, which contains a unit derived from the (meth)acrylic acid, 4. The aqueous ink according to any one of configurations 1 to 3, wherein at least a portion of the carboxylic acid groups is neutralized with an alkali. (Configuration 5) The aqueous ink according to any one of Configurations 1 to 4, wherein the total content (mass %) of the units derived from the (meth)acrylic acid ester and the units derived from the (meth)acrylic acid in the resin is 20 mass % or more based on the total mass of the resin. (Configuration 6) The resin is a water-soluble resin, The acid value of the water-soluble resin is 100 mgKOH / g or more and 180 mgKOH / g or less, 6. The water-based ink according to any one of configurations 1 to 5, wherein the water-soluble resin has a weight average molecular weight of 5,000 or more and 12,000 or less. (Configuration 7) The coloring material is a pigment, 7. The aqueous ink according to any one of configurations 1 to 6, wherein the resin is a dispersant for dispersing the pigment. (Configuration 8) The resin forms resin particles, The cumulative 50% particle diameter (D 50 6. The aqueous ink according to any one of configurations 1 to 5, wherein the average particle diameter is 50 nm or more and 250 nm or less. (Configuration 9) The aqueous ink according to any one of Configurations 1 to 8, which is an inkjet ink. (Configuration 10) A substrate and an image provided on a surface of the substrate, 10. A printed matter, wherein the image is formed using the aqueous ink according to any one of configurations 1 to 9.

Claims

1. An aqueous ink comprising a colorant and a resin including a unit derived from at least one selected from the group consisting of a biomass-derived (meth)acrylic acid ester and a biomass-derived (meth)acrylic acid.

2. 2. The aqueous ink according to claim 1, wherein the (meth)acrylic acid ester is an ester of (meth)acrylic acid and an alcohol having 1 to 22 carbon atoms.

3. 2. The aqueous ink according to claim 1, wherein the (meth)acrylic acid ester is at least one selected from the group consisting of n-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, and n-butyl methacrylate.

4. the resin is a resin containing a unit derived from the (meth)acrylic acid and having a carboxylic acid group in its molecule, 2. The aqueous ink according to claim 1, wherein at least a portion of the carboxylic acid groups are neutralized with an alkali.

5. 2. The aqueous ink according to claim 1, wherein the total content (mass %) of the units derived from the (meth)acrylic acid ester and the units derived from the (meth)acrylic acid in the resin is 20 mass % or more based on the total mass of the resin.

6. the resin is a water-soluble resin, The acid value of the water-soluble resin is 100 mgKOH / g or more and 180 mgKOH / g or less, 2. The water-based ink according to claim 1, wherein the water-soluble resin has a weight average molecular weight of 5,000 or more and 12,000 or less.

7. the coloring material is a pigment, 2. The water-based ink according to claim 1, wherein the resin is a dispersant for dispersing the pigment.

8. the resin forms resin particles, The cumulative 50% particle diameter (D ５０ 2. The aqueous ink according to claim 1, wherein the average particle diameter of the particles is 50 nm or more and 250 nm or less.

9. 10. The aqueous ink according to claim 1, which is an inkjet ink.

10. A substrate and an image provided on a surface of the substrate, A printed matter, wherein the image is formed using the aqueous ink according to claim 1 .

Images