Water-based inkjet ink composition

Abstract

The present invention provides an aqueous inkjet ink composition that exhibits excellent abrasion resistance, oil resistance, blocking resistance, and ejection stability. [Solution] An aqueous inkjet ink composition containing at least a pigment, a (meth)acrylic resin, resin fine particles, a silicone surfactant, and water, wherein the (meth)acrylic resin has a glass transition temperature of 20°C to 80°C, the resin fine particles have an average particle diameter of 150 nm or more, the silicone surfactant is dispersed when 2.5 parts by mass of the silicone surfactant is mixed with 97.5 parts by mass of water, and is dispersed when mixed with 97.5 parts by mass of a mixed solution in which the mass ratio of water to propylene glycol is 1:1, the content of the (meth)acrylic resin is 0.1% by mass or more and 3% by mass in terms of solids relative to the total mass of the aqueous inkjet ink composition, the content of the resin fine particles is 0.1% by mass or more and 3% by mass in terms of solids relative to the total mass of the aqueous inkjet ink composition, and the content of the silicone surfactant is 0.1% by mass or more and 2.5% by mass in terms of solids relative to the total mass of the aqueous inkjet ink composition.

Description

Technical Field

[0001] The present invention relates to an ink composition for aqueous inkjet.

Background Art

[0002] Ink compositions for aqueous inkjet are widely used because of their high safety and low environmental impact.

[0003] For example, Patent Document 1 discloses an ink composition containing first resin particles made of a resin other than a polyolefin-based resin and second resin particles made of a polyolefin-based resin, which is an inkjet ink composition used in a recording apparatus having a portion where members are pressed against each other by an external force inside an ink supply path for supplying the inkjet ink composition to an inkjet head. As the second resin particles, resin particles having a specific surface area obtained from the relaxation time of pulsed NMR of 0.18 m 2 / g or less are included, and an aqueous inkjet ink composition is disclosed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Conventional ink compositions for aqueous inkjet (simply referred to as ink compositions) have not been able to fully兼备 all of scratch resistance, oil resistance, blocking resistance, and ejection stability, and there has been room for further improvement.

[0006] Therefore, an object of the present invention is to provide an ink composition for aqueous inkjet that is excellent in scratch resistance, oil resistance, blocking resistance, and ejection stability. [Means for solving the problem]

[0007] The present invention relates to an aqueous inkjet ink composition containing at least a pigment, a (meth)acrylic resin, resin fine particles, a silicone surfactant, and water, wherein the (meth)acrylic resin has a glass transition temperature of 20°C to 80°C, the resin fine particles have an average particle size of 150 nm or more, the silicone surfactant is dispersed when 2.5 parts by mass of the silicone surfactant is mixed with 97.5 parts by mass of water, and is dispersed when mixed with 97.5 parts by mass of a mixed solution in which the mass ratio of water to propylene glycol is 1:1, the content of the (meth)acrylic resin is 0.1% to 3% by mass in terms of solids relative to the total mass of the aqueous inkjet ink composition, the content of the resin fine particles is 0.1% to 3% by mass in terms of solids relative to the total mass of the aqueous inkjet ink composition, and the content of the silicone surfactant is 0.1% to 2.5% by mass in terms of solids relative to the total mass of the aqueous inkjet ink composition.

[0008] In the aqueous inkjet ink composition of the present invention, it is preferable that the following formula (1) is satisfied when the solid content mass of the (meth)acrylic resin is (A) and the solid content mass of the resin fine particles is (B).

number

number

number

[0009] The present invention can provide an aqueous inkjet ink composition that is excellent in abrasion resistance, oil resistance, blocking resistance, and ejection stability. [Modes for carrying out the invention]

[0010] The aqueous inkjet ink composition of the present invention contains at least a pigment, a (meth)acrylic resin, resin fine particles, a silicone surfactant, and water, wherein the (meth)acrylic resin has a glass transition temperature of 20°C to 80°C, the resin fine particles have an average particle diameter of 150 nm or more, the silicone surfactant is dispersed when 2.5 parts by mass of the silicone surfactant is mixed with 97.5 parts by mass of water, and is also dispersed when mixed with 97.5 parts by mass of a mixed solution containing water and propylene glycol in a mass ratio of 1:1, the content of the (meth)acrylic resin is 0.1% to 3% by mass in terms of solids relative to the total mass of the aqueous inkjet ink composition, the content of the resin fine particles is 0.1% to 3% by mass in terms of solids relative to the total mass of the aqueous inkjet ink composition, and the content of the silicone surfactant is 0.1% to 2.5% by mass in terms of solids relative to the total mass of the aqueous inkjet ink composition. The following describes each component.

[0011] [Pigments] The aqueous inkjet ink composition of the present invention contains a pigment.

[0012] Any known pigment can be appropriately selected as the above-mentioned pigment.

[0013] Examples of organic pigments include azo pigments (e.g., azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments, etc.), polycyclic pigments (e.g., phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc.), dye chelates (e.g., basic dye type chelates, acid dye type chelates, etc.), nitro pigments, nitroso pigments, aniline black, and the like.

[0014] Examples of inorganic pigments include titanium oxide, zinc white, zinc sulfide, lead white, calcium carbonate, precipitated barium sulfate, white carbon, alumina white, kaolin clay, talc, bentonite, carbon black, black iron oxide, cadmium red, red iron oxide, molybdenum red, molybdate orange, chrome vermilion, lead yellow, cadmium yellow, yellow iron oxide, titanium yellow, chromium oxide, viridian, titanium cobalt green, cobalt green, cobalt chromium green, victoria green, ultramarine, navy blue, cobalt blue, cerulean blue, cobalt silica blue, cobalt zinc silica blue, manganese violet, cobalt violet, and the like.

[0015] The content of the above pigments is preferably 1% by mass or more and 20% by mass or less in terms of solid content based on the total mass of the aqueous inkjet ink composition, and more preferably 3% by mass or more and 10% by mass or less in terms of solid content.

[0016] [(Meth)acrylic resin] The aqueous inkjet ink composition of the present invention contains a (meth)acrylic resin. In this specification, “(meth)acrylic” means acrylic and / or methacrylic. The above (meth)acrylic resin is a component contained separately from the alkali-soluble resin used when producing the aqueous resin varnish described later.

[0017] Examples of the above (meth)acrylic resin include acrylic resins copolymerized with (meth)acrylic acid and its alkyl esters, or styrene, etc. as the main monomer components, styrene-acrylic resins, styrene-acrylic-maleic acid resins, and the like. These can be used alone or in combination of two or more.

[0018] The above (meth)acrylic resin has a glass transition temperature of 20°C or higher and 80°C or lower. When the glass transition temperature is within the above range, sufficient abrasion resistance and oil resistance can be imparted. The glass transition temperature of the above (meth)acrylic resin is preferably 25°C or higher and preferably 75°C or lower. In this specification, the "glass transition temperature" may be measured using a thermal analyzer such as a differential scanning calorimeter (DSC), or may be the theoretical glass transition temperature calculated by Fox's equation from the monomer units and their ratios constituting each resin. Fox's equation is, as shown below, a relational equation between the Tg of an acrylic polymer and the glass transition temperature Tgi of each homopolymer obtained by polymerizing each monomer constituting the acrylic polymer alone. 1 / Tg = Σ(Wi / Tgi) (In the formula, Tg represents the glass transition temperature of the acrylic polymer (unit: K), Wi represents the weight fraction of monomer i in the acrylic polymer (copolymerization ratio based on weight), and Tgi represents the glass transition temperature of the homopolymer of monomer i (unit: K)).

[0019] The content of the above (meth)acrylic resin is 0.1% by mass or more and 3% by mass or less in terms of solid content based on the total mass of the aqueous inkjet ink composition. When the content of the above (meth)acrylic resin is within the above range, sufficient oil resistance, blocking resistance, and ejection stability can be imparted. The content of the above (meth)acrylic resin is preferably 0.5% by mass or more and more preferably 0.75% by mass or more in terms of solid content based on the total mass of the aqueous inkjet ink composition. Furthermore, the content of the (meth)acrylic resin is preferably 2% by mass or less, and more preferably 1.5% by mass or less, based on the total mass of the aqueous inkjet ink composition.

[0020] In the aqueous inkjet ink composition of the present invention, from the viewpoint of suitably providing abrasion resistance and ejection stability, it is preferable that the following formula (1) is satisfied when the solid content mass of the (meth)acrylic resin is (A) and the solid content mass of the resin fine particles described later is (B).

number

[0021] In the aqueous inkjet ink composition of the present invention, from the viewpoint of suitably imparting oil resistance and blocking resistance, it is preferable that the following formula (2) is satisfied when the solid content mass of the (meth)acrylic resin is (A) and the solid content mass of the silicone-based surfactant described later is (C).

number

[0022] [Resin fine particles] The aqueous inkjet ink composition of the present invention contains resin fine particles.

[0023] Examples of the above-mentioned resin microparticles include wax, emulsion (polyethylene resin microparticles, urethane resin microparticles, polyolefin resin microparticles, vinyl acetate resin microparticles, vinyl chloride resin microparticles, fluorine resin microparticles, polyether resin microparticles, polyester resin microparticles, polycarbodiimide resin microparticles), colloidal silica, etc. From the viewpoint of abrasion resistance, the above resin fine particles are preferably in emulsion form, and more preferably polyethylene-based resin fine particles.

[0024] The above resin microparticles have an average particle diameter of 150 nm or more. By having the average particle size of the above-mentioned resin fine particles within the above range, abrasion resistance can be provided. The average particle size of the above resin fine particles is preferably 160 nm or larger, more preferably 170 nm or larger, and preferably 500 nm or smaller. The average particle size of the above-mentioned resin microparticles can be measured using a particle size distribution analyzer that employs dynamic light scattering theory as its measurement principle. Examples of such particle size distribution analyzers include the "Microtrac UPA" manufactured by Nikkiso Co., Ltd.

[0025] The content of the above resin fine particles is 0.1% by mass or more and 3% by mass or less in terms of solid content, relative to the total mass of the above aqueous inkjet ink composition. By having the above-mentioned resin fine particle content within the above range, sufficient abrasion resistance, oil resistance, and discharge stability can be provided. The content of the above-mentioned resin fine particles is preferably 0.5% by mass or more, and more preferably 0.75% by mass or more, based on the total mass of the aqueous inkjet ink composition. Furthermore, the content of the above-mentioned resin fine particles is preferably 2% by mass or less, and more preferably 1.5% by mass or less, based on the total mass of the aqueous inkjet ink composition.

[0026] In the aqueous inkjet ink composition of the present invention, from the viewpoint of suitably imparting abrasion resistance and blocking resistance, it is preferable that the following formula (3) is satisfied when the solid content mass of the resin fine particles is (B) and the solid content mass of the silicone-based surfactant described later is (C).

number

[0027] [Silicone-based surfactants] The aqueous inkjet ink composition of the present invention contains a silicone-based surfactant.

[0028] The above-mentioned silicone-based surfactant is dispersible in water (at 25°C). Specifically, when 2.5 parts by mass of the above-mentioned silicone-based surfactant is mixed with 97.5 parts by mass of water and left to stand for 1 hour, the silicone-based surfactant disperses in the solution and the appearance becomes cloudy.

[0029] The above-mentioned silicone-based surfactant is dispersible even in a mixed solution (at 25°C) in which the mass ratio of water to propylene glycol is 1:1. Specifically, when 2.5 parts by mass of the above-mentioned silicone-based surfactant is mixed with 97.5 parts by mass of a mixed solution in which the mass ratio of water to propylene glycol is 1:1, and allowed to stand for 1 hour, the above-mentioned silicone-based surfactant is dispersed in the solution and the appearance becomes cloudy.

[0030] Examples of the above-mentioned silicone-based surfactants include surfactants having a polysiloxane structure containing siloxane units. Furthermore, the polysiloxane structure may have, in addition to hydrogen atoms, unmodified, ether-modified, polyester-modified, epoxy-modified, amine-modified, carboxyl-modified, fluorine-modified, alkyloxy-modified, mercapto-modified, (meth)acrylic-modified, urethane-modified, phenol-modified, phenyl-modified, carbinol-modified, or aralkyl-modified hydrocarbon groups in its side chains.

[0031] Examples of commercially available silicone-based surfactants include BYK-378 (manufactured by BYK), GLIDE490 (manufactured by EVONIK), and Siltech E5050 (manufactured by Siltech).

[0032] The content of the above-mentioned silicone-based surfactant is 0.1% by mass or more and 2.5% by mass or less in terms of solid content, relative to the total mass of the above-mentioned aqueous inkjet ink composition. By having the above-mentioned content of the silicone-based surfactant within the above range, sufficient oil resistance, blocking resistance, and discharge stability can be provided. The content of the above-mentioned silicone-based surfactant is preferably 0.2% by mass or more, and more preferably 0.3% by mass or more, based on the total mass of the aqueous inkjet ink composition. Furthermore, the content of the above-mentioned silicone-based surfactant is preferably 1.5% by mass or less, and more preferably 1% by mass or less, based on the total mass of the aqueous inkjet ink composition.

[0033] [water] The aqueous inkjet ink composition of the present invention contains water.

[0034] The water content is preferably 15% to 70% by mass relative to the total mass of the aqueous inkjet ink composition.

[0035] [Organic solvents] The aqueous inkjet ink composition of the present invention may optionally contain an organic solvent.

[0036] The above organic solvent is preferably an alcohol or a polyhydric alcohol-based solvent.

[0037] Examples of the above-mentioned alcohols include methanol, ethanol, 1-propanol, isopropanol, 1-butanol, 2-butanol, isobutanol, and 2-methyl-2-propanol.

[0038] Examples of the above-mentioned polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, 1,3-propanediol, 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and glycerin.

[0039] The content of the above-mentioned organic solvent is preferably 5% by mass or more and 50% by mass or less based on the total mass of the aqueous inkjet ink composition.

[0040] (others) The aqueous inkjet ink composition of the present invention may contain various additives as needed. Specifically, examples include waxes, silica, light stabilizers, surface treatment agents, antioxidants, anti-aging agents, crosslinking accelerators, plasticizers, preservatives, pH adjusters, defoamers, and humectants. Surfactants other than silicone-based surfactants may also be added. These additives can be appropriately selected and used from known sources.

[0041] The content of the above additive is, for example, approximately 0% to 10% by mass in terms of solid content in the aqueous inkjet ink composition.

[0042] (Method for manufacturing water-based inkjet ink compositions) The method for producing the aqueous inkjet ink composition of the present invention is not particularly limited. For example, the above components may be added sequentially or simultaneously, mixed, stirred, and kneaded to produce the aqueous inkjet ink composition.

[0043] When mixing and stirring the above components in order, for example, an alkali-soluble resin, a basic compound, and water or a water-soluble organic solvent may be mixed to obtain an aqueous resin varnish, then the pigment may be mixed, stirred, and kneaded to prepare a pigment ink base, and then the resin emulsion, surfactant, and, if necessary, water or a water-soluble organic solvent may be mixed and stirred to prepare an aqueous inkjet ink composition.

[0044] Examples of alkali-soluble resins used in preparing the above-mentioned aqueous resin varnish include acrylic resins, styrene-acrylic resins, styrene-maleic acid resins, styrene-acrylic-maleic acid resins, polyurethane resins, and polyester resins copolymerized with acrylic acid or methacrylic acid and its alkyl esters, or styrene, as the main monomer components. These alkali-soluble resins can be used individually or in mixtures of two or more types.

[0045] Basic compounds used in preparing the above-mentioned aqueous resin varnish include ammonia, organic amines, alkali metal hydroxides, and the like. Examples of the above-mentioned organic amines include alkylamines such as diethylamine, triethylamine, and ethylenediamine, and alkanolamines such as monoethanolamine, ethylethanolamine, diethylethanolamine, diethanolamine, and triethanolamine. Furthermore, examples of the alkali metal hydroxides mentioned above include sodium hydroxide and potassium hydroxide.

[0046] The method for mixing, stirring, and kneading the meat described above is not particularly limited, and may be used in known ways, such as using a bead mill, ready mill, ultrasonic homogenizer, high-pressure homogenizer, paint shaker, ball mill, roll mill, sand mill, sand grinder, Dino mill, Dispermat, SC mill, nanomizer, etc.

[0047] The method for printing the aqueous inkjet ink composition of the present invention is not particularly limited, and the ink can be printed on the substrate using a known inkjet printing apparatus.

[0048] This specification discloses the following:

[0049] (1) This disclosure relates to an aqueous inkjet ink composition containing at least a pigment, a (meth)acrylic resin, resin fine particles, a silicone surfactant, and water, wherein the (meth)acrylic resin has a glass transition temperature of 20°C to 80°C, the resin fine particles have an average particle size of 150 nm or more, and the silicone surfactant is a mixed solution containing 2.5 parts by mass of the silicone surfactant when mixed with 97.5 parts by mass of water, and in which the mass ratio of water to propylene glycol is 1:1, comprising 97.5 parts by mass. An aqueous inkjet ink composition wherein the (meth)acrylic resin content is 0.1% to 3% by mass in terms of solid content relative to the total mass of the aqueous inkjet ink composition, the resin fine particles content is 0.1% to 3% by mass in terms of solid content relative to the total mass of the aqueous inkjet ink composition, and the silicone surfactant content is 0.1% to 2.5% by mass in terms of solid content relative to the total mass of the aqueous inkjet ink composition.

[0050] Disclosure (2) is an aqueous inkjet ink composition according to Disclosure (1), wherein the solid content mass of the (meth)acrylic resin is (A) and the solid content mass of the resin fine particles is (B), and the following formula (1) is satisfied.

number

number

number

[0051] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "%" means "mass%" and "parts" means "parts by mass".

[0052] The materials used in the examples and comparative examples are as follows:

[0053] <(meth)acrylic resin> Acrylic resin 1 (JONCRYL PDX-7356, manufactured by BASF, glass transition temperature: 25°C, solids content: 45.5%) Acrylic resin 2 (JONCRYL PDX-7615, manufactured by BASF, glass transition temperature: 33°C, solids content: 50.5%) Acrylic resin 3 (JONCRYL PDX-7630A, manufactured by BASF, glass transition temperature: 53°C, solids content: 32.0%) Acrylic resin 4 (JONCRYL PDX-7538, manufactured by BASF, glass transition temperature: 75°C, solids content: 45.5%) Acrylic resin 5 (JONCRYL PDX-7326, manufactured by BASF, glass transition temperature: 9°C, solids content: 38.5%) Acrylic resin 6 (JONCRYL PDX-7696, manufactured by BASF, glass transition temperature: 86°C, solids content: 40.0%) The glass transition temperature is stated as the value obtained by the method described herein.

[0054] <Resin fine particles> Resin microparticles 1 (HORDAMER PE 03, manufactured by BYK, polyethylene resin emulsion, average particle size: 200 nm, solids content: 40%) Resin microparticles 2 (AQUACER 515, manufactured by Tetsutani Co., Ltd., polyethylene resin emulsion, average particle size: 30 nm, solid content: 35%) The average particle size is the value obtained by the method described herein.

[0055] <Silicone-based surfactants> Silicone-based surfactant 1 (TEGO Glide490, manufactured by Evonik, solids content: 65%) Silicone-based surfactant 2 (BYK-378, manufactured by BYK, solids content: 100%) Silicone-based surfactant 3 (Siltech E5050, manufactured by SILTECH CORPORATION, solids content: 30%) Silicone-based surfactant 4 (TEGO Glide 496, manufactured by Evonik, solids content: 100%) Silicone-based surfactant 5 (BYK-SILCLEAN 3720, manufactured by BYK, solids content: 25%)

[0056] <Dispersibility of silicone-based surfactants> 97.5 parts by mass of water and 97.5 parts by mass of a mixed solution in which the mass ratio of water to propylene glycol is 1:1 were each mixed with 2.5 parts by mass of a silicone-based surfactant, and the appearance of the liquid was checked after standing for 1 hour. The water and mixed solutions were kept at 25°C. In Table 1, the dispersibility in water and the dispersibility in mixed solutions were evaluated according to the following criteria. Products that received an "A" rating for both dispersibility in water and dispersibility in mixed solutions were judged to be acceptable. (Evaluation Criteria) A: It was confirmed that the silicone-based surfactant was dispersed (the appearance was cloudy). B: It was confirmed that a silicone-based surfactant was dissolved (the appearance was transparent). C: Silicone-based surfactant had separated.

[0057] [Table 1]

[0058] <Other surfactants (excluding silicone-based surfactants)> Surfactant 1 (surfynol 465, manufactured by Nisshin Chemical Co., Ltd., acetylene glycol-based surfactant) Surfactant 2 (Triton HW1000, manufactured by Dow, polyoxyethylene alkyl ether-based surfactant) Surfactant 3 (Persoft EF, manufactured by NOF Corporation, sodium polyoxyethylene lauryl ether sulfate-based surfactant)

[0059] <Organic solvents> Propylene glycol 1,3-butanediol

[0060] <Water> purified water

[0061] <Preparation of water-based resin varnish> Thirty parts by mass of acrylic acid / stearyl acrylate / styrene copolymer was dissolved in a mixed solution of 3.8 parts by mass of potassium hydroxide and 66.2 parts by mass of water to obtain an aqueous resin varnish with a solid content of 30%.

[0062] <Preparation of water-based ink base> (Water-based black ink) A resin varnish for pigment dispersion was prepared by adding 48 parts by mass of water to 32 parts by mass of the above aqueous resin varnish and mixing. To this pigment dispersion resin varnish, 20 parts by mass of carbon black (product name Printex 90, manufactured by Orion Engineered Carbons) were added, stirred and mixed, and then kneaded in a wet circulation mill to prepare an aqueous black ink base (containing 20% ​​by mass of pigment).

[0063] (Water-based yellow ink) A resin varnish for pigment dispersion was prepared by adding 48 parts by mass of water to 32 parts by mass of the above aqueous resin varnish and mixing. To this pigment dispersion resin varnish, 20 parts by mass of yellow pigment (product name Novapalm Yellow 4G01, manufactured by Clariant) were added, stirred and mixed, and then kneaded in a wet circulation mill to prepare an aqueous yellow ink base (containing 20% ​​by mass of pigment).

[0064] (Water-based magenta ink) A resin varnish for pigment dispersion was prepared by adding 48 parts by mass of water to 32 parts by mass of the above aqueous resin varnish and mixing. To this pigment dispersion resin varnish, 20 parts by mass of magenta pigment (product name Inkjet Magenta E5B02, manufactured by Clariant) were added, stirred and mixed, and then kneaded in a wet circulation mill to prepare an aqueous magenta ink base (containing 20% ​​by mass of pigment).

[0065] (Water-based cyan ink) A resin varnish for pigment dispersion was prepared by adding 48 parts by mass of water to 32 parts by mass of the above aqueous resin varnish and mixing. To this pigment dispersion resin varnish, 20 parts by mass of cyan pigment (product name Heliogen Blue L7101F, manufactured by BASF) were added, stirred and mixed, and then kneaded in a wet circulation mill to prepare an aqueous cyan ink base (containing 20% ​​by mass of pigment).

[0066] <Preparation of water-based inkjet ink compositions> (Examples 1-17, Comparative Examples 1-14) Based on Tables 2 and 3, the aqueous ink base, (meth)acrylic resin, resin fine particles, organic solvent, surfactant, and water were stirred and mixed to produce the aqueous inkjet ink compositions of Examples 1 to 17 and Comparative Examples 1 to 14.

[0067] [Table 2]

[0068] [Table 3]

[0069] <Evaluation Results> A water-based inkjet ink composition was spread onto OK Topcoat+ (manufactured by Oji Paper Co., Ltd.) using a 0.1 mm meter bar, and dried at 70°C for 3 minutes to prepare a colored sample. The above-mentioned colored material was used to evaluate abrasion resistance, oil resistance, blocking resistance, and discharge stability using the following method.

[0070] [Abrasion resistance] A cotton swab (product name: Cotton Stick Cotton Swab, manufactured by Asai Shoji Co., Ltd.) was attached to a pencil hardness tester (product name: Wolf-Wilburn, manufactured by BYK-Gardner), and the colored surface of the above-mentioned material was rubbed with a fixed pressure of 750g. After that, the colored surface was visually inspected and evaluated according to the following criteria. We judged items with an "◎" rating or a "〇" rating to be passing grades. (Evaluation Criteria) ◎: Even after rubbing with a cotton swab 10 times, there was absolutely no smudging. ○: After rubbing 10 times with a cotton swab, the color transferred to the cotton swab, and the rubbed area became slightly faded. ×: After rubbing with a cotton swab 10 times, the entire rubbed area peeled off.

[0071] [Oil resistance] A cotton swab (product name: Cotton Stick Cotton Swab, manufactured by Asai Shoji Co., Ltd.) coated with salad oil (product name: Nisshin Salad Oil, manufactured by Nisshin Oillio Co., Ltd.) was attached to a pencil hardness tester (product name: Wolf-Wilburn, manufactured by BYK-Gardner Co., Ltd.), and the colored surface of the above-mentioned material was rubbed with a fixed pressure of 750g. After that, the colored surface was visually inspected and evaluated according to the following criteria. We judged items with an "◎" rating or a "〇" rating to be passing grades. (Evaluation Criteria) ◎: No signs of ink being removed. ○: It appears that a small amount of ink has been removed. ×: Areas where the ink has been removed are visible, leaving the paper surface exposed.

[0072] [Blocking resistance] The colored surface and non-colored surface of each exhibiting material are combined, and then 9.8 × 10 4Pa(1kgf / cm 2 The following pressure was applied: After being left at 40°C for 24 hours, the sample was peeled off and its blocking resistance was evaluated. We judged items with an "◎" rating or a "〇" rating to be passing grades. (Evaluation Criteria) ◎: When the non-adherent surface is peeled off, there is absolutely no peeling of the adhering surface. ○: When the non-adhering surface is peeled off, less than 10% peeling occurs on the adhering surface. ×: When the non-adherent surface is peeled off, more than 10% peeling occurs on the adhering surface.

[0073] [Discharge stability] Water-based inkjet ink compositions were loaded into cartridges of an Epson PX105 printer, and 50 consecutive 15cm x 20cm solid images were printed on Canon GL-101A450 photo paper. The results were evaluated according to the following criteria. We judged items with an "◎" rating or a "〇" rating to be passing grades. (Evaluation Criteria) ◎: Prints without irregularities and can be ejected stably. ○: Although there are some printing irregularities, it is still usable. ×: Printing is irregular and cannot be ejected stably.

[0074] [Table 4]

[0075] [Table 5]

[0076] Tables 3 and 4 confirm that the aqueous inkjet ink compositions of the examples exhibit excellent resistance to abrasion, oil, blocking, and ejection stability. [Industrial applicability]

[0077] The present invention can provide an aqueous inkjet ink composition that is excellent in abrasion resistance, oil resistance, blocking resistance, and ejection stability.

Claims

1. An aqueous inkjet ink composition containing at least a pigment, a (meth)acrylic resin, resin fine particles, a silicone surfactant, and water, The (meth)acrylic resin has a glass transition temperature of 20°C or higher and 80°C or lower. The resin fine particles have an average particle diameter of 150 nm or more. The aforementioned silicone-based surfactant is such that when 2.5 parts by mass of the silicone-based surfactant is mixed with 97.5 parts by mass of water, it becomes dispersed, and when mixed with 97.5 parts by mass of a mixed solution in which the mass ratio of water to propylene glycol is 1:1, it becomes dispersed. The content of the (meth)acrylic resin is 0.1% by mass or more and 3% by mass or less in terms of solid content, relative to the total mass of the aqueous inkjet ink composition. The content of the resin fine particles is 0.1% by mass or more and 3% by mass or less in terms of solid content, relative to the total mass of the aqueous inkjet ink composition. The content of the silicone-based surfactant is 0.1% by mass or more and 2.5% by mass or less in terms of solid content, relative to the total mass of the aqueous inkjet ink composition. A water-based inkjet ink composition.

2. The aqueous inkjet ink composition according to claim 1, wherein the following formula (1) is satisfied when (A) is the solid content mass of the (meth)acrylic resin and (B) is the solid content mass of the resin fine particles. [Math 1]

3. The aqueous inkjet ink composition according to claim 1 or 2, wherein the following formula (2) is satisfied when (A) is the solid content mass of the (meth)acrylic resin and (C) is the solid content mass of the silicone surfactant. [Math 2]

4. The aqueous inkjet ink composition according to claim 1 or 2, wherein the following formula (3) is satisfied when (B) is the solid content mass of the resin fine particles and (C) is the solid content mass of the silicone-based surfactant. [Math 3]

5. The aqueous inkjet ink composition according to claim 1 or 2, wherein the (meth)acrylic resin has a glass transition temperature of 25°C or more and 75°C or less.

6. The aqueous inkjet ink composition according to claim 1 or 2, wherein the resin fine particles are polyethylene-based resin fine particles.

Images