Ink composition for aqueous inkjet and printed matter

Abstract

This ink composition for an aqueous inkjet contains a pigment, an anionic group-containing resin, a resin emulsion, a surfactant, a water-soluble solvent, and water, and the water-soluble solvent contains 90 mass% or more of a water-soluble solvent having a boiling point of 200 DEG C or less at 1 atmospheric pressure. The surfactant contains a polyoxyethylene alkyl ether having an HLB value of from 7 to 12 (inclusive) and a polysiloxane-based surfactant satisfying specific conditions. The ink composition for an aqueous ink jet has excellent discharge stability, good filling of a full plate portion without irregularities even when printing and recording are performed on a non-absorbent printing medium, and excellent paper surface dryness.

Description

Technical Field

[0001] The invention relates to an aqueous inkjet ink composition and printed matter. Background Art

[0002] Inkjet printing and recording is a printing and recording method in which droplets of an aqueous inkjet ink composition are directly ejected from a very fine nozzle onto a printing and recording medium and attached to the medium to obtain text or images. Usually, such an aqueous inkjet ink composition contains a pigment, an alkali-soluble resin, a surfactant, a water-soluble solvent, and water. For example, Patent Document 1 discloses an aqueous inkjet ink composition containing a pigment, an anionic resin (alkali-soluble resin), a resin emulsion, a specific surfactant, a water-soluble solvent, and water.

[0003] Background Art Literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-222754 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] The requirements are as follows: as the aqueous inkjet ink composition disclosed in Patent Document 1, the ejection stability is excellent, and even in the case of inkjet printing and recording on non-absorbent printing media (mediums) such as coated paper or polyvinyl chloride sheets, the filling of the full printing area is good and there is no unevenness in the full printing area. In addition, from the perspective of shortening the drying time of printed materials and improving productivity, an aqueous inkjet ink composition with good paper surface drying is required.

[0008] The present invention has been completed in view of the above-mentioned actual situation, and its purpose is to provide an aqueous inkjet ink composition which has excellent ejection stability, and even when printing or recording on a non-absorbent printing medium, the filling of the solid part is good and uneven, and further has excellent paper surface drying property.

[0009] Technical means of solving problems

[0010] [Item 1] That is, the present invention relates to an aqueous inkjet ink composition, which contains a pigment, a resin containing an anionic group, a resin emulsion, a surfactant, a water-soluble solvent and water, wherein the water-soluble solvent contains 90% by mass or more of a water-soluble solvent having a boiling point of 200° C. or less at 1 atmosphere, the surfactant contains a polyoxyethylene alkyl ether and a polysilicone surfactant, the HLB value of the polyoxyethylene alkyl ether is 7 or more and 12 or less, and the polysilicone surfactant satisfies the following conditions: a mixture consisting of 99.9 parts by mass of water and 0.1 parts by mass of the polysilicone surfactant has a maximum value (specific transmittance 1) of 30% or less at a wavelength of 380 nm to 780 nm at 25° C., and satisfies the following conditions: a mixture consisting of 89.9 parts by mass of water, 10 parts by mass of diethylene glycol monobutyl ether and 0.1 parts by mass of the polysilicone surfactant has a maximum value (specific transmittance 2) of 95% or more at a wavelength of 380 nm to 780 nm at 25° C.

[0011] [Item 2] Furthermore, the present invention relates to the aqueous inkjet ink composition according to Item 1 above, which contains one or more surfactants selected from acetylene glycol-based surfactants and alkanediol-based surfactants.

[0012] [Item 3] Furthermore, the present invention relates to the aqueous inkjet ink composition according to Item 1 or 2 above, wherein the water-soluble solvent having a boiling point of 200° C. or less at 1 atmosphere is propylene glycol.

[0013] [Item 4] In addition, the present invention relates to an aqueous inkjet ink composition according to any one of Items 1 to 3 above, wherein the resin emulsion is selected from one or more of an acrylic resin emulsion and a styrene-acrylic resin emulsion.

[0014] [Item 5] Furthermore, the present invention relates to the aqueous inkjet ink composition according to any one of Items 1 to 4 above, wherein the glass transition temperature of the resin in the resin emulsion is -35°C or higher and 35°C or lower.

[0015] [Item 6] In addition, the present invention relates to an aqueous inkjet ink composition according to any one of the preceding items 1 to 5, wherein the polyoxyethylene alkyl ether is a branched chain in which the carbon number of the alkyl group is greater than 10 and less than 15, and the average added molar number of the ethyleneoxy group is greater than 3 and less than 10.

[0016] [Item 7] Furthermore, the present invention relates to a printed matter obtained by printing the aqueous inkjet ink composition according to any one of Items 1 to 6 above.

[0017] Effects of the Invention

[0018] Although the mechanism of the effect of the present invention is not clear, it is speculated as follows. Different from the composition of the patent document 1, the aqueous inkjet ink composition of the present invention reduces the surface tension of the ink droplets on the printing medium by using a specific polyoxyethylene alkyl ether as a surfactant, and optimizes the wetting and diffusion of the ink dots. Furthermore, in the process of ink drying, the water in the ink evaporates, and even when the ratio of the water-soluble solvent in the ink component is relatively large, the effect of reducing the surface tension can be maintained, so the uneven drying can be suppressed and the ink can be dried evenly. Therefore, even when the aqueous inkjet ink composition is inkjet printed and recorded on non-absorbent printing media such as coated paper or polyvinyl chloride sheets, the ejection stability of the ink composition is excellent, and the full-page portion of the printed and recorded image is well filled, and the full-page portion is uneven. In addition, since it contains a specific amount of a water-soluble solvent having a boiling point of less than 200°C at 1 atmosphere, the paper surface is excellent in drying. Therefore, the aqueous inkjet ink composition of the present invention has coating stability for these non-absorbent printing media and can form good printed and recorded images. DETAILED DESCRIPTION

[0019] The aqueous inkjet ink composition of the present invention contains at least a pigment, an anionic group-containing resin, a resin emulsion, a surfactant, a water-soluble solvent and water.

[0020] <Pigment>

[0021] The pigment can be an organic pigment or an inorganic pigment used in an inkjet ink composition without particular limitation. As the organic pigment, for example, dye lake pigments, azo pigments, benzimidazolone pigments, phthalocyanine pigments, quinacridone pigments, anthraquinone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, perylene pigments, pyrenone pigments, dione pyrrolopyrrole pigments, isoindolinone pigments, nitro pigments, nitroso pigments, flavanthronone pigments, quinoline yellow pigments, pyranthrone pigments, indanthrene pigments, etc. In addition, as the inorganic pigment, for example, carbon black, titanium oxide, zinc flower, red iron, graphite, iron black, chromium oxide green, aluminum hydroxide, etc. can be cited. The pigment may be a pigment surface-treated with a known surface treatment agent. At least one of the pigments may be used, and two or more of the pigments may be used in combination.

[0022] Specific examples of representative hues of the above-mentioned pigments include the following hues.

[0023] Examples of the yellow pigment include CI Pigment Yellow 1, 2, 3, 12, 13, 14, 16, 17, 42, 73, 74, 75, 81, 83, 87, 93, 95, 97, 98, 108, 109, 114, 120, 128, 129, 138, 139, 150, 151, 155, 166, 180, 184, 185, and 213.

[0024] Examples of the magenta pigment include CI Pigment Red 5, 7, 12, 22, 38, 48:1, 48:2, 48:4, 49:1, 53:1, 57, 57:1, 63:1, 101, 102, 112, 122, 123, 144, 146, 149, 168, 177, 178, 179, 180, 184, 185, 190, 202, 209, 224, 242, 254, 255, 270, and CI Pigment Violet 19.

[0025] Examples of the cyan pigment include CI Pigment Blue 1, 2, 3, 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 18, 22, 27, 29, and 60.

[0026] Examples of the black pigment include carbon black (CI Pigment Black 7).

[0027] Examples of the white pigment include titanium oxide and aluminum oxide, and the white pigment may be surface-treated with various materials such as aluminum oxide and silicon dioxide.

[0028] Based on the viewpoint of improving the image density of the printed matter, the ratio of the pigment in the aqueous inkjet ink composition is preferably 1% by mass or more, more preferably 2% by mass or more, and, based on the viewpoint of improving the ejection stability, preferably 10% by mass or less, more preferably 8% by mass or less. Wherein, in the case where the pigment is a white pigment, the ratio of the white pigment in the aqueous inkjet ink composition is preferably 4% by mass or more, more preferably 8% by mass or more, and, preferably 30% by mass or less, more preferably 20% by mass or less. That is, based on the viewpoint of improving the image density of the printed matter and the viewpoint of improving the ejection stability, the ratio of the pigment in the aqueous inkjet ink composition is preferably 1% by mass or more and 10% by mass or less, more preferably 2% by mass or more and 8% by mass or less. In addition, in the case where the pigment is a white pigment, the ratio of the white pigment in the aqueous inkjet ink composition is preferably 4% by mass or more and 30% by mass or less, more preferably 8% by mass or more and 20% by mass or less.

[0029] <Anionic group-containing resin>

[0030] The anionic group-containing resin is not particularly limited as long as it is an alkali-soluble resin that can be used to disperse the pigment of a common ink or coating or can be used as a binder and can be dissolved in an aqueous medium in the presence of an alkaline compound. Preferably, it is a resin containing one or more anionic groups such as a carboxyl group, a sulfonic acid group, or a phosphonic acid group.

[0031] The anionic group-containing resin further preferably has a hydrophobic portion "mainly for improving the adsorption of the pigment" and / or a hydrophilic portion "mainly for obtaining the effect of effectively preventing aggregation in an aqueous medium" in the molecule. Examples of the hydrophobic portion introduced into the molecule include hydrophobic groups such as long-chain alkyl groups, alicyclic or aromatic cyclic hydrocarbon groups, and examples of the hydrophilic portion introduced into the molecule include hydrophilic groups such as (poly)oxyalkylene chains, basic nitrogen-containing groups, hydroxyl groups, and epoxy groups.

[0032] The acid value of the anionic group-containing resin is preferably 50 mgKOH / g or more. Based on the viewpoint of improving the dispersion stability of the pigment, the acid value of the anionic group-containing resin is preferably 60 mgKOH / g or more, and more preferably 70 mgKOH / g or more. Based on the viewpoint of improving the water resistance of the printed matter, the acid value of the anionic group-containing resin is preferably 350 mgKOH / g or less, and more preferably 300 mgKOH / g or less. That is, based on the viewpoint of improving the dispersion stability of the pigment and the viewpoint of improving the water resistance of the printed matter, the acid value of the anionic group-containing resin is preferably 60 mgKOH / g or more and 350 mgKOH / g or less, and more preferably 70 mgKOH / g or more and 300 mgKOH / g or less. In addition, the acid value is a theoretical acid value, that is, the number of mg of potassium hydroxide theoretically required to neutralize 1 g of the anionic group-containing resin is arithmetically calculated based on the composition of the monomer used to synthesize the anionic group-containing resin.

[0033] From the viewpoint of improving the dispersion stability of the pigment, the weight average molecular weight of the anionic group-containing resin is preferably 3,000 or more, more preferably 7,000 or more. From the viewpoint of improving the solubility in the aqueous medium described below, the weight average molecular weight of the anionic group-containing resin is preferably 200,000 or less, more preferably 100,000 or less.

[0034] The weight average molecular weight can be measured by gel permeation chromatography (GPC). For example, Water 2690 (manufactured by Waters) can be used as a GPC device, PLgel, 5μ, MIXED-D (manufactured by Polymer Laboratories) can be used as a column, tetrahydrofuran can be used as a developing solvent, and chromatographic analysis can be performed under the conditions of a column temperature of 25°C, a flow rate of 1 ml / min, an RI detector, a sample injection concentration of 10 mg / ml, and an injection volume of 100 microliters to obtain the weight average molecular weight calculated as polystyrene.

[0035] As the anionic group-containing resin, for example, acrylic acid copolymer resin, maleic acid copolymer resin, polyester resin and polyurethane resin obtained by polycondensation reaction can be cited. Regarding the material used to synthesize this type of anionic group-containing resin, for example, it has been disclosed in Japanese Patent Publication No. 2000-94825, and acrylic acid copolymer resin, maleic acid copolymer resin, polyester resin, polyurethane resin and the like obtained by using the materials recorded in the publication can be used. Furthermore, resins obtained by using other materials can also be used. As long as at least one anionic group-containing resin is used, two or more can be combined for use.

[0036] As the acrylic copolymer resin, for example, the following can be used: a mixture of other monomers copolymerizable with the anionic group-containing monomer is polymerized in a solvent in the presence of a common free radical generator (for example, benzoyl peroxide, t-butyl perbenzoate, azobisisobutyronitrile, etc.).

[0037] Examples of the anionic group-containing monomer include monomers having at least one anionic group selected from a carboxyl group, a sulfonic acid group, and a phosphonic acid group. Among these, monomers having a carboxyl group are particularly preferred.

[0038] Examples of the monomer having a carboxyl group include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, 2-carboxyethyl (meth)acrylate, 2-carboxypropyl (meth)acrylate, maleic anhydride, fumaric anhydride, maleic acid half ester, etc. Examples of the monomer having a sulfonic acid group include sulfoethyl methacrylate, etc. Examples of the monomer having a phosphonic acid group include isophosphite ethyl methacrylate, etc.

[0039] As the other monomer copolymerizable with the anionic group-containing monomer, it is preferred that a hydrophobic group-containing monomer be contained from the viewpoint of improving the adsorption property to the pigment.

[0040] Examples of the hydrophobic group-containing monomer include, for example, monomers having a long-chain alkyl group, such as alkyl esters of free-radically polymerizable unsaturated carboxylic acids having 8 or more carbon atoms such as (meth)acrylic acid (e.g., 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, 2-hydroxystearyl (meth)acrylate, etc.), alkyl vinyl ethers having 8 or more carbon atoms (e.g., dodecyl vinyl ether, etc.), and vinyl esters of fatty acids having 8 or more carbon atoms (e.g., vinyl 2-ethylhexanoate, vinyl laurate, vinyl stearate, etc.); examples of monomers having an alicyclic hydrocarbon group include cyclohexyl (meth)acrylate, etc.; examples of monomers having an aromatic hydrocarbon group include styrene monomers such as benzyl (meth)acrylate, styrene, α-styrene, and vinyl toluene, etc.

[0041] As the other monomer copolymerizable with the anionic group-containing monomer, it is preferred that a hydrophilic group-containing monomer be included from the viewpoint of suppressing aggregation of the anionic group-containing resin in the aqueous medium described below.

[0042] Examples of the hydrophilic group-containing monomer include, for example, monomers having a (poly)oxyalkylene chain, such as esters of (poly)alkylene glycols terminated at one end with an alkyl group, such as methoxy polyethylene glycol, methoxy polyethylene polypropylene glycol, ethoxy polyethylene glycol, ethoxy polyethylene polypropylene glycol, propoxy polyethylene glycol, propoxy polyethylene polypropylene glycol, and free radical polymerizable unsaturated carboxylic acids, such as (meth)acrylic acid, or ethylene oxide adducts and / or propylene oxide adducts of free radical polymerizable unsaturated carboxylic acids, such as (meth)acrylic acid; and examples of the basic group-containing monomer include, for example, vinyl pyrrolidones such as 1-vinyl-2-pyrrolidone and 1-vinyl-3-pyrrolidone, vinyl pyridines such as 2-vinylpyridine, 4-vinylpyridine, 5-methyl-2-vinylpyridine, and 5-ethyl-2-vinylpyridine, and 1-vinylpyridine. Examples of the monomer having a hydroxyl group include vinyl imidazoles such as 1-vinyl-2-methylimidazole, vinyl piperidines such as 3-vinyl piperidine and N-methyl-3-vinyl piperidine, nitrogen-containing derivatives of (meth)acrylic acid such as dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, tert-butylaminoethyl (meth)acrylate, (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide, N-methoxy (meth)acrylamide, N-ethoxy (meth)acrylamide, N-dimethylacrylamide, and N-propylacrylamide; examples of the monomer having a hydroxyl group include hydroxyalkyl esters of (meth)acrylic acid such as hydroxyethyl (meth)acrylate and hydroxypropyl (meth)acrylate; examples of the monomer having an epoxy group include glycidyl (meth)acrylate, and the like.

[0043] Examples of other copolymerizable monomers other than the hydrophobic group-containing monomer and the hydrophilic group-containing monomer include alkyl esters of (meth)acrylic acid having less than 8 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, and hexyl (meth)acrylate.

[0044] Based on the viewpoint of improving the dispersion stability of the pigment, the amount of the anionic group-containing resin used is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and more preferably 30 parts by mass or more relative to 100 parts by mass of the pigment. Based on the viewpoint of reducing the viscosity of the ink composition, the amount of the anionic group-containing resin used is preferably 100 parts by mass or less, more preferably 80 parts by mass or less, and more preferably 60 parts by mass or less relative to 100 parts by mass of the pigment. That is, based on the viewpoint of improving the dispersion stability of the pigment and reducing the viscosity of the ink composition, the amount of the anionic group-containing resin used is preferably 10 parts by mass or more and 100 parts by mass or less, more preferably 20 parts by mass or more and 80 parts by mass or less, and more preferably 30 parts by mass or more and 60 parts by mass or less relative to 100 parts by mass of the pigment.

[0045] <Basic compounds>

[0046] From the viewpoint of dissolving the anionic group-containing resin, the aqueous inkjet ink composition preferably contains an alkaline compound. Examples of the alkaline compound include inorganic alkaline compounds such as sodium hydroxide and potassium hydroxide; organic alkaline compounds such as ammonia, methylamine, ethylamine, monoethanolamine, N,N-dimethylethanolamine, N,N-diethylethanolamine, N,N-dibutylethanolamine, diethanolamine, N-methyldiethanolamine, triethanolamine, morpholine, N-methylmorpholine, and N-ethylmorpholine. The alkaline compound may be used alone or in combination of two or more.

[0047] Regarding the ratio of the basic compound in the aqueous inkjet ink composition, as long as it is an amount that can dissolve the anionic group-containing resin in the medium, it is usually preferably 0.05% by mass or more, more preferably 0.1% by mass or more, based on the viewpoint of improving the dispersion stability of the anionic group-containing resin, and preferably 1% by mass or less, more preferably 0.5% by mass or less, based on the viewpoint of improving the water resistance of the printed matter. That is, based on the viewpoint of improving the dispersion stability of the anionic group-containing resin and the viewpoint of improving the water resistance of the printed matter, the ratio of the basic compound in the aqueous inkjet ink composition is preferably 0.05% by mass or more and 1% by mass or less, more preferably 0.1% by mass or more and 0.5% by mass or less.

[0048] <Resin emulsion>

[0049] The resin emulsion is an aqueous emulsion. Examples of the aqueous emulsion include acrylic resin emulsion, styrene-acrylic resin emulsion, polyester resin emulsion, polyurethane resin emulsion, polyvinyl acetate resin emulsion, polyvinyl chloride resin emulsion, polybutadiene resin emulsion, polyethylene resin emulsion, etc. Among them, acrylic resin emulsion and styrene-acrylic resin emulsion are preferred in terms of excellent appearance and various resistances such as water resistance, solvent resistance, scratch resistance, and heat resistance of the obtained printed matter. At least one of the resin emulsions can be used, and two or more can be used in combination.

[0050] From the viewpoint of improving the ejection stability of the ink composition, the glass transition temperature of the resin in the resin emulsion is preferably -35°C or higher, more preferably -30°C or higher, and further preferably -20°C or higher. From the viewpoint of improving the film-forming property of the ink on the printing medium, the glass transition temperature of the resin in the resin emulsion is preferably 35°C or lower, more preferably 30°C or lower, and further preferably 20°C or lower. That is, from the viewpoint of improving the ejection stability of the ink composition and the viewpoint of improving the film-forming property of the ink on the printing medium, the glass transition temperature of the resin in the resin emulsion is preferably -35°C or higher and 35°C or lower, more preferably -30°C or higher and 30°C or lower, and further preferably -20°C or higher and 20°C or lower.

[0051] When the resin of the emulsion is an acrylic resin or a styrene-acrylic resin emulsion, the glass transition temperature of the resin of the resin emulsion is a theoretical glass transition temperature calculated according to the following Wood's formula.

[0052] Wood's formula: 1 / Tg=W1 / Tg1+W2 / Tg2+W3 / Tg3+·····+Wx / Tgx

[0053] [Wherein, Tg1~Tgx represent the glass transition temperature of the homopolymer of each of monomers 1, 2, 3...x constituting the anionic group-containing resin, W1~Wx represent the polymerization fraction of each of monomers 1, 2, 3...x, and Tg represents the theoretical glass transition temperature; wherein the glass transition temperature in Wood's formula is an absolute temperature.]

[0054] The glass transition temperature of the resin of the emulsion other than the acrylic resin or styrene-acrylic resin is the measured glass transition temperature obtained by thermal analysis. As a thermal analysis method, JIS K7121 (Method for Determining Transition Temperature of Plastics) can be used. For example, the glass transition temperature is measured using a Pyrisl DSC manufactured by PerkinElmer at a heating rate of 20°C / min and a nitrogen flow rate of 20 ml / min.

[0055] From the viewpoint of improving the ejection stability of the ink composition, the average particle size of the resin emulsion is preferably 500 nm or less, more preferably 300 nm or less. As an example, the average particle size of the emulsion can be obtained by measuring the D50 value using a Microtrac particle size distribution measuring machine "UPA-150" manufactured by Nikkiso, with a measuring time of 60 seconds and water as a diluent.

[0056] Based on the viewpoint of suppressing the unevenness of the full-page portion of the printed and recorded image, the ratio of the resin solid content of the resin emulsion in the aqueous inkjet ink composition is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and further preferably 1% by mass or more. Based on the viewpoint of suppressing the viscosity of the ink composition, the ratio of the resin solid content of the resin emulsion in the aqueous inkjet ink composition is preferably 20% by mass or less, more preferably 10% by mass or less. That is, based on the viewpoint of suppressing the unevenness of the full-page portion of the printed and recorded image and the viewpoint of suppressing the viscosity of the ink composition, the ratio of the resin solid content of the resin emulsion in the aqueous inkjet ink composition is preferably 0.1% by mass or more and 20% by mass or less, more preferably 0.5% by mass or more and 10% by mass or less, and further preferably 1% by mass or more and 10% by mass or less.

[0057] <Surfactant>

[0058] The surfactant includes polyoxyethylene alkyl ether and polysilicone surfactant.

[0059] The polyoxyethylene alkyl ether is a nonionic surfactant having an HLB value of 7 or more and 12 or less. From the viewpoint of miscibility, the HLB value of the polyoxyethylene alkyl ether is preferably 7.5 or more, more preferably 8 or more, and from the viewpoint of optimizing full-page filling of printing and recording images, it is preferably 11.5 or less, more preferably 11 or less. That is, from the viewpoint of miscibility and optimizing full-page filling of printing and recording images, the HLB value of the polyoxyethylene alkyl ether is preferably 7.5 or more and 11.5 or less, more preferably 8 or more and 11 or less. In addition, the HLB value refers to an index indicating the degree of hydrophilicity and lipophilicity of a surfactant calculated by the Griffin method. The smaller the HLB value, the higher the lipophilicity, and the larger the HLB value, the higher the hydrophilicity. At least one of the polyoxyethylene alkyl ethers can be used, and two or more can be used in combination.

[0060] As long as the polyoxyethylene alkyl ether satisfies the HLB value, the carbon number of the alkyl group and the average number of moles of the ethyleneoxy group are not particularly limited, for example, the carbon number is preferably about 10 to about 15, and the average number of moles of the ethyleneoxy group is preferably about 3 to about 10. In addition, the alkyl group may be a linear or branched chain, and is preferably a branched chain from the viewpoint of optimizing full-screen filling of printed and recorded images.

[0061] The polysilicone surfactant is a compound having a polysiloxane skeleton and satisfies the following conditions: the maximum transmittance (specific transmittance 1) of a mixture consisting of 99.9 parts by mass of water and 0.1 parts by mass of the polysilicone surfactant at a wavelength of 380nm to 780nm at 25°C is 30% or less, and the following conditions are satisfied: the maximum transmittance (specific transmittance 2) of a mixture consisting of 89.9 parts by mass of water, 10 parts by mass of diethylene glycol monobutyl ether and 0.1 parts by mass of the polysilicone surfactant at a wavelength of 380nm to 780nm at 25°C is 95% or more.

[0062] Specific examples of the silicone-based surfactants include, for example, BYK-347, BYK-377, and BYK-3455 manufactured by BYK-Chemie Japan Co., Ltd., as shown in Japanese Unexamined Patent Application Publication No. 2016-222754. At least one of the silicone-based surfactants may be used, and two or more thereof may be used in combination.

[0063] <Other surfactants>

[0064] As other surfactants other than the polyoxyethylene alkyl ether and the polysilicone surfactant, known surfactants can be used. In particular, acetylene glycol surfactants and alkane glycol surfactants are preferred from the viewpoint of having an effect of improving the full filling of the printed and recorded images of the aqueous inkjet ink composition.

[0065] From the viewpoint of optimizing solid filling of printed and recorded images, the ratio of the polyoxyethylene alkyl ether in the aqueous inkjet ink composition is preferably 0.2 to 2% by mass, and more preferably 0.4 to 1% by mass.

[0066] From the viewpoint of enhancing the effect of suppressing unevenness of solid areas of printed or recorded images of the ink composition, the ratio of the silicone surfactant in the aqueous inkjet ink composition is preferably 0.01 to 1% by mass, more preferably 0.05 to 0.5% by mass.

[0067] <Water-soluble solvent>

[0068] The water-soluble solvent contains 90% by mass or more of a water-soluble solvent having a boiling point of 200° C. or less at 1 atmosphere.

[0069] The water-soluble solvent having a boiling point of 200° C. or less at 1 atmosphere can be any known water-soluble solvent for an aqueous inkjet ink composition that satisfies such a boiling point without particular limitation, and examples thereof include monoalcohols, polyols, lower alkyl ethers of polyols, nitrogen-containing compounds, etc. At least one water-soluble solvent having a boiling point of 200° C. or less at 1 atmosphere can be used, and two or more kinds thereof can be used in combination.

[0070] Examples of the water-soluble solvent having a boiling point of 200° C. or less at 1 atmosphere include 1-octanol (boiling point 195° C.), 2-ethylhexanol (boiling point 184° C.), propylene glycol (boiling point 188° C.), 1,2-butanediol (boiling point 197° C.), ethylene glycol (boiling point 197° C.), 3-methoxy-3-methyl-1-butanol (boiling point 174° C.), diethylene glycol (boiling point 245° C.), dipropylene glycol monomethyl ether (boiling point 188° C.), dipropylene glycol dimethyl ether (boiling point 175° C.), diethylene glycol monomethyl ether (boiling point 194° C.), and diethylene glycol monoethyl ether (boiling point 196° C.).

[0071] Based on the viewpoint of improving the ejection stability of the ink composition and the formation of the ink film on the non-absorbing printing medium (media), the ratio of the water-soluble solvent in the aqueous inkjet ink composition is preferably 15% by mass or more, and more preferably 25% by mass or more. Based on the viewpoint of improving the storage stability of the ink composition, the ratio of the water-soluble solvent in the aqueous inkjet ink composition is preferably 50% by mass or less, and more preferably 45% by mass or less. That is, based on the viewpoint of improving the ejection stability of the ink composition, the formation of the ink film on the non-absorbing printing medium (media) and the viewpoint of improving the storage stability of the ink composition, the ratio of the water-soluble solvent in the aqueous inkjet ink composition is preferably 15% by mass or more and 50% by mass or less, and more preferably 25% by mass or more and 45% by mass or less.

[0072] <Water>

[0073] The water includes water as an aqueous medium contained in the pigment dispersion described below and water added to adjust the concentration of the aqueous inkjet ink composition of the present invention. Examples of the water include ion exchange water, pure water, distilled water, industrial water, etc. At least one type of the water may be used, and two or more types may be used in combination.

[0074] Based on the viewpoint of improving the ejection stability of the ink composition, the ratio of water in the aqueous inkjet ink composition is preferably 40% by mass or more, and more preferably 45% by mass or more. Based on the viewpoint of improving the ejection stability of the ink composition, the ratio of water in the aqueous inkjet ink composition is preferably 70% by mass or less, and more preferably 65% ​​by mass or less. That is, based on the viewpoint of improving the ejection stability of the ink composition, the ratio of water in the aqueous inkjet ink composition is preferably 40% by mass or more and 70% by mass or less, and more preferably 45% by mass or more and 65% by mass or less.

[0075] <Other additives>

[0076] The aqueous inkjet ink composition of the present invention may further contain known resins, wax emulsions, pigment dispersants, mildew inhibitors, rust inhibitors, thickeners, antioxidants, ultraviolet absorbers, storage life enhancers, defoamers, pH adjusters, etc., depending on the purpose.

[0077] <Method for preparing aqueous inkjet ink composition>

[0078] The preparation of each aqueous inkjet ink composition can be carried out by any conventional preparation method, and the components can be added and mixed in sequence or simultaneously. For example, the following method can be mentioned: (1) an aqueous resin varnish obtained by dissolving an anionic group-containing resin in an aqueous medium in the presence of the alkaline compound, a pigment, and a pigment dispersant as required are mixed, and then a pigment dispersion (ink) is prepared by using various dispersers such as a ball mill, an attritor, a roller mill, a sand mill, and an agitator mill. base material), and then adding other materials to prepare an aqueous inkjet ink composition; or (2) after dispersing the pigment by the above method, obtaining a resin-coated pigment with an alkali-soluble resin precipitated on the surface of the pigment by an acid precipitation method or an ion exchange method described in Japanese Patent Re-publication No. WO2005 / 116147, then neutralizing the obtained resin-coated pigment with an alkaline compound, and dispersing it again in water using various dispersers (high-speed stirring devices, etc.), and then adding other materials to prepare an aqueous inkjet ink composition.

[0079] The initial viscosity of each aqueous inkjet ink composition is preferably 2.0 to 15.0 mPa·s, more preferably 3.0 to 10.0 mPa·s. The viscosity can be measured, for example, using an E-type viscometer (trade name: RE100L viscometer, manufactured by Toki Sangyo Co., Ltd.).

[0080] <Printed Materials>

[0081] The printed matter of the present invention is obtained by printing the aqueous inkjet ink composition. As the printing medium of the aqueous inkjet ink composition, coated paper such as coated paper, inkjet paper and inkjet glossy paper, non-absorbent printing medium such as plastic substrates such as polyvinyl chloride sheets, and non-coated paper such as plain paper or offset paper can be used.

[0082] As a printing method of the aqueous inkjet ink composition, for example, the following method can be cited: the aqueous inkjet ink composition is contained in an ink cartridge, the ink cartridge is installed in an inkjet recording device such as a single-channel method, and the ink is ejected from a nozzle toward the printing medium, thereby performing inkjet printing.

[0083] [Example]

[0084] The present invention will be described in further detail below with reference to Examples, but the present invention is not limited to these Examples. In addition, "%" means "mass %" unless otherwise specified.

[0085] <Measurement of specific permeability 1 of a mixture of silicone surfactants>

[0086] A mixture of 99.9 parts by mass of water and 0.1 parts by mass of the silicone surfactant was prepared, and the transmittance of the mixture at wavelengths of 380 nm to 780 nm at 25° C. was measured using a rectangular quartz cell with an optical path length of 10 mm to determine the maximum value (specific transmittance 1).

[0087] Measuring machine: UV-2500PC (manufactured by Shimadzu Corporation)

[0088] Measurement conditions: slit width 2nm, scanning speed high speed, measurement start wavelength 780nm, measurement end wavelength 380nm, sampling interval automatic, measurement mode single mode. Water was used as a reference.

[0089] Table 1 shows the results.

[0090] <Measurement of specific permeability 2 of a mixture of silicone surfactants>

[0091] A mixture consisting of 89.9 parts by mass of water, 10 parts by mass of diethylene glycol monobutyl ether (BDG) and 0.1 parts by mass of the polysilicone surfactant was prepared. The transmittance of the mixture at a wavelength of 380 nm to 780 nm at 25° C. was measured using a rectangular quartz cell with an optical path length of 10 mm to obtain the maximum value (specific transmittance 2).

[0092] Measuring machine: UV-2500PC (manufactured by Shimadzu Corporation)

[0093] Measurement conditions: slit width 2nm, scanning speed high speed, measurement start wavelength 780nm, measurement end wavelength 380nm, sampling interval automatic, measurement mode single mode. Water was used as a reference.

[0094] The results are shown in Table 2.

[0095] [Table 1]

[0096]

[0097] [Table 2]

[0098] In Tables 1 and 2, BYK-347 indicates a solid content of 100%, a polyether-modified silicone surfactant, manufactured by BYK-Chemie Japan;

[0099] BYK-3455 means solid content 100%, polyether modified siloxane surfactant, manufactured by BYK-Chemie Japan;

[0100] BYK-333 means solid content 100%, polyether modified siloxane type surfactant, manufactured by BYK-ChemieJapan;

[0101] BYK-348 means solid content 100%, polyether modified silicone type surfactant, manufactured by BYK-Chemie Japan;

[0102] TEGO WET 270 means solid content 100%, polyether modified siloxane copolymer, manufactured by EVONIK;

[0103] Silface SAG005 indicates solid content 97%, polyether modified siloxane type surface conditioning

[0104]

[0105] Agent, manufactured by Nissin Chemical Industry Co., Ltd.

[0106] <Manufacturing of water-based resin varnish>

[0107] 20 parts by mass of an acrylic acid / lauryl acrylate / styrene copolymer (anionic group-containing resin) having a glass transition temperature of 45° C., a weight average molecular weight of 30,000, and an acid value of 185 mgKOH / g was dissolved in a mixed solution of 2.5 parts by mass of potassium hydroxide and 77.5 parts by mass of water to obtain an aqueous resin varnish having a solid content of 20%.

[0108] <Preparation of black ink base>

[0109] 64.3 parts by mass of water were added to 23.7 parts by mass of the aqueous resin varnish and mixed to prepare a pigment dispersion resin varnish. 12 parts by mass of carbon black (trade name Printex 90, manufactured by Degussa) was further added to the varnish, stirred and mixed, and then ground using a wet circulation grinder to prepare a black ink base material.

[0110] <Preparation of yellow ink base>

[0111] 64.3 parts by mass of water were added to 23.7 parts by mass of the aqueous resin varnish and mixed to prepare a pigment dispersion resin varnish. 12 parts by mass of a yellow pigment (trade name Novoperm Yellow 4G01, manufactured by Clariant) was further added to the varnish, stirred and mixed, and then ground using a wet circulation grinder to prepare a yellow ink base.

[0112] <Preparation of magenta ink base>

[0113] 64.3 parts by mass of water were added to 23.7 parts by mass of the aqueous resin varnish and mixed to prepare a pigment dispersion resin varnish. 12 parts by mass of a magenta pigment (trade name: Ink JetMagenta E5B02, manufactured by Clariant) was further added to the varnish, stirred and mixed, and then ground using a wet circulation grinder to prepare a magenta ink base.

[0114] <Preparation of cyan ink base>

[0115] 64.3 parts by mass of water were added to 23.7 parts by mass of the aqueous resin varnish and mixed to prepare a pigment dispersion resin varnish. 12 parts by mass of a cyan pigment (trade name Heliogen Blue L7101F, manufactured by BASF) was further added to the varnish, stirred and mixed, and then ground using a wet circulation grinder to prepare a cyan ink base.

[0116] <Manufacturing of aqueous inkjet ink composition>

[0117] <Example 1>

[0118] The black ink base, propylene glycol, Triton HW1000 (polyoxyethylene alkyl ether, nonionic surfactant, manufactured by DOW) as a surfactant, BYK-347, NeoCrylΑ-1092 (styrene-acrylic resin emulsion, resin glass transition temperature 9°C, manufactured by Covestro Coating Resins) as a resin emulsion, and water are stirred and mixed in a manner to obtain the mass ratio shown in Table 3 to prepare the aqueous inkjet ink composition of Example 1.

[0119] <Examples 2 to 14, Comparative Examples 1 to 8>

[0120] In each of the examples and comparative examples, except that the raw materials and their amounts were changed as shown in Tables 3 and 4, the aqueous inkjet ink compositions of each of the examples and comparative examples were prepared by the same method as in Example 1.

[0121] <Evaluation of aqueous inkjet ink composition>

[0122] Evaluation was performed by the following method, and the results are shown in Tables 3 and 4.

[0123] <Ejection stability of ink composition>

[0124] The aqueous inkjet ink composition obtained above was loaded into the ink cartridge of an inkjet printer PX105 (manufactured by Epson), printed on coated paper (OK Topcoat+, manufactured by Prince Paper Co., Ltd.), and the ejection stability was evaluated. Regarding the qualified benchmark, as long as it is △ or 0, it is more preferably 0.

[0125] [Evaluation criteria]

[0126] 0: Almost no printing disturbance, stable ejection

[0127] △: Although the printing is somewhat disordered, it can be ejected

[0128] ×: Unable to eject

[0129] <Paper surface drying properties>

[0130] The aqueous inkjet ink composition obtained above was loaded into the ink cartridge of an inkjet printer PX105 (manufactured by Epson), and printed on coated paper (OK Topcoat+, manufactured by Oji Paper Co., Ltd.), and the obtained printed matter was placed at 80°C for 1 minute, and then the printed part was wiped with a cotton swab, and the dryness was evaluated according to the degree of ink adhesion. As for the pass standard, it only needs to be △ or 0, and more preferably 0.

[0131] [Evaluation criteria]

[0132] 0: No ink adhered at all

[0133] △: A small amount of ink is attached

[0134] ×: A large amount of ink is attached

[0135] <Filling the entire printed image>

[0136] The aqueous inkjet ink composition obtained above was loaded into an ink cartridge of an inkjet printer PX105 (manufactured by Epson), and full printing was performed on coated paper (OK Topcoat+, manufactured by Prince Paper Co., Ltd.), and the formation of full printing was visually evaluated for stripes and blanks. Regarding the qualified standard, as long as it is △ or 0, it is more preferably 0.

[0137] [Evaluation criteria]

[0138] 0: No streaks or blanks

[0139] △: There are some streaks and blank spaces

[0140] ×: There are many streaks and blank spaces.

[0141] <Unevenness of the solid area of ​​the printed image>

[0142] The aqueous inkjet ink composition obtained above was loaded into an ink cartridge of an inkjet printer PX105 (manufactured by Epson), and full printing was performed on coated paper (OK Topcoat+, manufactured by Prince Paper Co., Ltd.), and the unevenness of full printing was evaluated by visual inspection. Regarding the qualified standard, as long as it is △ or 0, it is more preferably 0.

[0143] [Evaluation criteria]

[0144] 0: No uneven printing

[0145] △: Some parts have uneven printing

[0146] ×: The printing is uneven overall

[0147] [Table 3]

[0148]

[0149] [Table 4]

[0150]

[0151] In Tables 3 and 4, Triton HW1000 represents polyoxyethylene alkyl ether, HLB value is 10.9, nonionic surfactant, manufactured by DOW;

[0152] Genapol X050 represents polyoxyethylene alkyl ether, HLB value is 10.6, nonionic surfactant, manufactured by Clariant;

[0153] SANNONIC SS-30 means polyoxyethylene alkyl ether, HLB value is 8.0, nonionic surfactant, manufactured by Sanyo Chemical Co.;

[0154] NEWCOL 2502A indicates polyoxyethylene alkyl ether, HLB value is 6.3, nonionic surfactant, manufactured by Japan Emulsifier Co., Ltd.

[0155] SANNONIC SS-70 means polyoxyethylene alkyl ether, HLB value is 12.1, nonionic surfactant, manufactured by Sanyo Chemical Co., Ltd.

[0156] EMULGEN 1135S-70 means polyoxyethylene alkyl ether, HLB value is 17.9, nonionic surfactant, manufactured by Kao Corporation;

[0157] Surfynol AD01 represents an alkanediol-based surfactant, a nonionic surfactant, manufactured by EVONIK;

[0158] NeoCrylΑ-1092 represents a styrene-acrylic resin emulsion with a glass transition temperature of 9°C, manufactured by Covestro Coating Resins;

[0159] NeoCrylΑ-655 represents a styrene-acrylic resin emulsion with a glass transition temperature of 33°C, manufactured by Covestro Coating Resins;

[0160] YODOSOL AD173 represents an acrylic resin emulsion with a glass transition temperature of -25°C, manufactured by Henkel;

[0161] Mowinyl 966A is a styrene-acrylic resin emulsion having a glass transition temperature of -32°C and is manufactured by Japan Coating Resin Co., Ltd.

Claims

1. An aqueous inkjet ink composition comprising a pigment, an anionic resin, a resin emulsion, a surfactant, a water-soluble solvent and water, characterized in that: The water-soluble solvent contains 90% by mass or more of a water-soluble solvent having a boiling point of 200° C. or less at 1 atmosphere, The surfactant contains polyoxyethylene alkyl ether and polysilicone surfactant. The HLB value of the polyoxyethylene alkyl ether is greater than or equal to 7 and less than or equal to 12, The polysilicone surfactant meets the following conditions: The maximum transmittance (specific transmittance 1) of a mixture consisting of 99.9 parts by mass of water and 0.1 parts by mass of the polysilicone-based surfactant at 25° C. at a wavelength of 380 nm to 780 nm is 30% or less, and the following conditions are satisfied: The maximum transmittance (specific transmittance 2) of a mixture consisting of 89.9 parts by mass of water, 10 parts by mass of diethylene glycol monobutyl ether and 0.1 parts by mass of the silicone surfactant at 25° C. at a wavelength of 380 nm to 780 nm is 95% or more.

2. The aqueous inkjet ink composition according to claim 1, characterized in that: The present invention contains at least one surfactant selected from acetylene glycol-based surfactants and alkanediol-based surfactants.

3. The aqueous inkjet ink composition according to claim 1 or 2, characterized in that: The water-soluble solvent having a boiling point of 200° C. or less at 1 atmosphere is propylene glycol.

4. The aqueous inkjet ink composition according to claim 1 or 2, characterized in that: The resin emulsion is selected from at least one of acrylic resin emulsion and styrene-acrylic resin emulsion.

5. The aqueous inkjet ink composition according to claim 1 or 2, characterized in that: The glass transition temperature of the resin in the resin emulsion is -35°C or higher and 35°C or lower.

6. The aqueous inkjet ink composition according to claim 1 or 2, characterized in that: The polyoxyethylene alkyl ether is a branched chain in which the carbon number of the alkyl group is 10 or more and 15 or less, and the average number of added moles of the ethyleneoxy group is 3 or more and 10 or less.

7. A printed matter, characterized in that: The aqueous inkjet ink composition according to claim 1 or 2 is printed.

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