Manufacturing method for printed matter with inkjet ink

Abstract

To provide a manufacturing method for a printed matter with inkjet ink which can provide a printed matter which is excellent in discharge stability and mechanical stability and also is excellent in drying characteristics and abrasion resistance.SOLUTION: In a manufacturing method for a printed matter with water-based inkjet ink, water-based inkjet ink including pigment, an organic solvent and wax, and a line pass-type inkjet printing device are used. The line pass-type inkjet printing device has circulating means comprising a diaphragm pump, which circulates the water-based inkjet ink, from an outflow passage of a head toward an inflow passage thereof, using the diaphragm pump. Circulating flow volumes of the water-based inkjet ink with respect to maximum flow volumes by the diaphragm pump are over 0% and 30% or below.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing inkjet ink prints. [Background technology]

[0002] Among various color printing methods, inkjet printing, one of the most representative methods, generates small droplets of ink and deposits them on a printing medium such as paper to print. In recent years, demand for inkjet printers for industrial use has increased, and there is a demand for inks that can be used to print on a variety of printing media. Among printing media, for non-ink-absorbent media and poorly ink-absorbent media (hereinafter sometimes referred to as "non-ink / poorly ink-absorbent media"), there is a demand for ink that dries quickly on the media and has excellent abrasion resistance. In general, reducing the content of high-boiling-point organic solvents in ink is expected to improve the drying and fixation of the ink. Furthermore, various resins are added to ink to make it scratch-resistant, and it is known that the greater the amount of resin added, the better the scratch resistance. However, reducing the amount of high-boiling-point organic solvent and increasing the amount of resin added makes the ink more susceptible to drying, which can lead to problems such as ink sticking on the head nozzle surface and reduced ejection reliability. Meanwhile, in recent years, circulation heads have been actively developed that have a mechanism for preventing ink from drying out near the nozzles by circulating the ink up to the nozzles. In printing devices with such ink circulation mechanisms, when ink is circulated for a long period of time, precipitates may form due to the shear forces applied when passing through the filters inside the device or when being pumped. When such precipitates form, the filters inside the head become clogged, which ultimately shortens the head life of the inkjet head (for example, resulting in poor ejection). In order to alleviate the above problems, there is a need for a method for producing an inkjet ink printed matter that is excellent in ejection stability and mechanical stability, as well as quick drying and abrasion resistance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6952208 [Patent Document 2] Patent No. 6922189 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention has been made in consideration of the above circumstances, and aims to provide a method for producing an inkjet ink printed matter that makes it possible to provide a printed matter that has excellent ejection stability and mechanical stability, as well as quick-drying properties and excellent abrasion resistance. [Means for solving the problem]

[0005] As a result of intensive research into solving the above-mentioned problems, the inventors have found that the above-mentioned problems can be solved by a method for producing an aqueous ink-jet ink printed matter, which method uses an aqueous ink-jet ink containing a pigment, an organic solvent, and a wax, and a line-pass type ink-jet printing apparatus, the line-pass type ink-jet printing apparatus being equipped with a diaphragm pump and having circulation means for circulating the aqueous ink-jet ink from an outlet flow path to an inlet flow path by the diaphragm pump, and wherein the circulation flow rate of the aqueous ink-jet ink is more than 0% and not more than 30% of the maximum flow rate of the diaphragm pump, and have thus completed the present invention.

[0006] That is, the present invention relates to the following 1) to 3). 1) Using water-based inkjet ink containing pigments, organic solvents, and wax, and a line-pass type inkjet printing device, the line pass type inkjet printing apparatus has a diaphragm pump, and a circulation means for circulating the water-based inkjet ink from an outlet flow path of a head to an inlet flow path by the diaphragm pump; a circulation flow rate of the water-based inkjet ink exceeding 0% and not exceeding 30% of a maximum flow rate of the diaphragm pump. 2) 1) The method for producing a water-based inkjet ink printed matter according to 1), wherein the organic solvent contains at least one organic solvent having a surface tension of 30 to 50 mN / m and a boiling point of 180°C or higher at 1 atmospheric pressure. 3) The method for producing a water-based inkjet ink printed matter according to 1) or 2), wherein the content by mass of the organic solvent having a surface tension of 30 to 50 mN / m and a boiling point of 180°C or higher at 1 atmosphere is 15 mass% or less relative to the total mass of the water-based inkjet ink. [Effects of the Invention]

[0007] The present invention provides a method for producing a water-based inkjet ink print that is excellent in ejection stability and mechanical stability, as well as in drying properties and abrasion resistance. DETAILED DESCRIPTION OF THE INVENTION

[0008]

[0023] In this specification, including the examples, "parts" and "%" are all based on mass unless otherwise specified. Furthermore, in this specification, the water-based inkjet ink may be abbreviated as "inkjet ink" or "ink," and the method for producing a water-based inkjet ink-printed product may be abbreviated as "production method."

[0009] The method for producing an aqueous inkjet ink print of the present invention uses an aqueous inkjet ink containing a pigment, an organic solvent, and a wax, and a line-pass type inkjet printing apparatus, wherein the line-pass type inkjet printing apparatus is equipped with a diaphragm pump and a circulation means for circulating the aqueous inkjet ink from an outlet flow path to an inlet flow path of a head using the diaphragm pump, and the circulation flow rate of the aqueous inkjet ink is more than 0% and not more than 30% of the maximum flow rate of the diaphragm pump.

[0010] [Pigment] The ink contains a pigment. Examples of the pigment include inorganic pigments, organic pigments, extender pigments, and hollow particles.

[0011] Examples of inorganic pigments include carbon black, metal oxides, metal hydroxides, metal sulfides, metal ferrocyanides, and metal chlorides. When the ink according to this embodiment is a black ink and the pigment is inorganic, the inorganic pigment contained in the black ink is preferably carbon black such as thermal black, acetylene black, oil furnace black, gas furnace black, lamp black, gas black, channel black, etc. Specific examples of carbon black include the Raven series manufactured by Columbia Carbon; the Monarch series, Regal series, and Mogul series manufactured by Cabot Corporation; the HiBlack series, ColorBlack series, Printex series, SpecialBlack series, and Nerox series manufactured by Orion Engineered Carbons; and the MA series, MCF series, No. 25, No. 33, No. 40, No. 47, No. 52, No. 900, and No. 2300 manufactured by Mitsubishi Chemical Corporation. When the ink according to this embodiment is a white ink and the pigment is an inorganic pigment, examples of the inorganic pigment contained in the white ink include oxides, nitrides, and oxynitrides of metals such as zinc, silicon, aluminum, titanium, strontium, and zirconium; inorganic compounds such as glass and silica; etc. Among these, titanium dioxide and zinc oxide are preferred.

[0012] Examples of organic pigments include various pigments such as azo, disazo, phthalocyanine, quinacridone, isoindolinone, dioxazine, perylene, perinone, thioindigo, anthraquinone, and quinophthalone.

[0013] Specific examples of organic pigments include yellow pigments such as CI Pigment Yellow 1, 2, 3, 12, 13, 14, 16, 17, 24, 55, 73, 74, 75, 83, 93, 94, 95, 97, 98, 108, 114, 128, 129, 138, 139, 150, 151, 154, 155, 180, 185, 193, 199, 202, and 213; Red pigments such as 5, 7, 12, 48, 48:1, 57, 88, 112, 122, 123, 146, 149, 150, 166, 168, 177, 178, 179, 184, 185, 202, 206, 207, 254, 255, 257, 260, 264, 269, and 272; blue pigments such as CI Pigment Blue 1, 2, 3, 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 22, 25, 60, 66, and 80; violet pigments such as CI Pigment Violet 19, 23, 29, 37, 38, and 50; orange pigments such as CI Pigment Orange 13, 16, 43, 68, 69, 71, and 73; and CI Pigment Green green pigments such as CI Pigment Black 1, CI Pigment Blue 15:4, etc., and black pigments such as CI Pigment Black 1. Of these, CI Pigment Blue 15:4 is preferred.

[0014] Examples of extender pigments include silica, calcium carbonate, talc, clay, barium sulfate, white carbon, etc. Extender pigments are often used in combination with other colorants.

[0015] As the hollow particles, known hollow particles described in, for example, U.S. Pat. No. 4,880,465, Japanese Patent No. 3,562,754, Japanese Patent No. 6,026,234, Japanese Patent No. 5,459,460, JP-A-2003-268694, Japanese Patent No. 4,902,216, etc. can be used, and they are particularly preferably used as white pigments.

[0016] The average particle size of the pigment is preferably 30 to 300 nm, more preferably 50 to 250 nm. In this specification, the average particle size refers to the average particle size of particles measured using a laser light scattering method.

[0017] The pigment content is preferably 1 to 30 mass %, more preferably 1 to 10 mass %, and even more preferably 2 to 8 mass %, relative to the total mass of the ink according to this embodiment.

[0018] The ink may further contain other dyes in addition to the pigments. Examples of the other dyes include solvent dyes, direct dyes, acid dyes, and reactive dyes.

[0019] When the ink contains multiple pigments, the blending ratio of the pigments can be set arbitrarily depending on the purpose. When the ink contains other dyes in addition to the pigments, the blending ratio of the total amount of the pigments to the total amount of the other dyes can also be set arbitrarily.

[0020] [wax] The ink contains a wax. The wax is preferably a wax emulsion, more preferably an aqueous wax emulsion. Natural waxes and synthetic waxes can be used as the wax. Of these, synthetic waxes are preferred. The synthetic waxes include polyethylene waxes, preferably oxidized polyethylene waxes, and more preferably polyethylene wax emulsions. The average particle size of the wax is preferably 40 nm to 5 μm, more preferably 40 nm to 1 μm, in order to prevent clogging of the inkjet head.

[0021] Commercially available polyethylene wax emulsions include, for example, AQUACER 515(45) and 1547 manufactured by BYK-Chemie, and the HYTEC E series manufactured by Toho Chemical Industry Co., Ltd., such as E-6500(40), E-9015(45), and E-6314(85). The numerical values ​​in parentheses following each wax indicate the average particle size (unit: nm) of each wax. The content of wax relative to the total mass of the ink is usually 0.1 to 10%, preferably 0.2 to 8%, more preferably 0.4 to 5%, even more preferably 0.6 to 3%, and particularly preferably 0.8 to 1.2%. By setting the wax content to 0.1 to 10%, the scratch resistance of the printed matter can be improved. In the above ink, it is preferable to use AQUACER 515 as the wax.

[0022] [Organic solvents] The ink contains an organic solvent. The organic solvent is selected from the viewpoints of improving the wetting and spreading properties of the ink on the "recording medium" described below, improving the ink drying properties and abrasion resistance, and ensuring ejection properties from inkjet nozzles. In particular, in order to obtain an ink with favorable print image quality, drying properties, abrasion resistance, and ejection stability when used in combination with a binder resin, the organic solvent preferably contains at least one organic solvent having a surface tension of 30 to 50 mN / m and a boiling point at 1 atmosphere of 180°C or higher, more preferably at least one organic solvent having a boiling point of 180°C to 230°C, even more preferably at least one organic solvent having a boiling point of 180°C to 220°C, and particularly preferably at least one organic solvent having a boiling point of 180°C to 210°C. In the present invention, the surface tension is determined by the Wilhelmy The boiling point in this embodiment can be measured using a thermal analysis device such as a thermogravimetric-differential thermal analyzer (TG-DTA). Specific examples of organic solvents having a surface tension of 30 mN / m or more and 50 mN / m or less and a boiling point of 180°C or higher under 1 atmosphere include polyol solvents such as ethylene glycol, propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, 3-methyl-1,3-butanediol, 2,2-dimethyl-1,3-propanediol, and dipropylene glycol; ethylene glycol monoether solvents such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobenzyl ether, diethylene glycol monopropyl ether, and diethylene glycol monoisopropyl ether; ethylene glycol monoether acetate solvents such as diethylene glycol monoethyl ether acetate; and nitrogen-containing solvents such as N,N-dimethyl-β-methoxypropionamide, N-methylpyrrolidone, and γ-butyrolactone. In this specification, an organic solvent having a surface tension of 30 mN / m or more and 50 mN / m or less and a boiling point of 180°C or higher under 1 atmosphere may be abbreviated as organic solvent A. The organic solvent A may be used alone or in combination of two or more kinds.

[0023] It is also preferable to select one or more specific organic solvents selected from ethylene glycol and propylene glycol, which are alkanediols having a carbon number of 3 or less, as the organic solvent A. The alkanediols having a carbon number of 3 or less have a low boiling point among the specific organic solvents, and inks using the alkanediols having a carbon number of 3 or less have particularly excellent drying properties.

[0024] In another embodiment, the present invention preferably uses one or more organic solvents selected from alkanediols having four or more carbon atoms, such as 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, 3-methyl-1,3-butanediol, and 2,2-dimethyl-1,3-propanediol. Among these, it is particularly preferable to use one or more water-soluble organic solvents selected from linear alkanediols, such as 1,2-butanediol, 1,3-butanediol, and 1,4-butanediol. It is most preferable to use 1,2-butanediol, a 1,2-alkanediol. Alkanediols having four or more carbon atoms contain a hydroxyl group, which is a hydrophilic unit, and an alkyl group, which is a hydrophobic unit, in each molecule. While having a high affinity for water, they are also thought to be able to reduce the surface tension of the ink to a suitable range, similar to a binder resin. This improves the wetting and spreading properties of the ink, making it easier to obtain printed matter with excellent print quality.

[0025] The content of the organic solvent A is preferably 1 to 15% by mass, more preferably 1.5 to 14% by mass, and most preferably 2 to 14% by mass, relative to the total mass of the ink. When the content of the organic solvent A is 1 to 15% by mass, it is possible to achieve a balance between the penetration power and drying speed of the ink on the recording medium while imparting moisture retention to the inkjet head, thereby ensuring ejection stability and achieving good print image quality, drying speed, and abrasion resistance even in high-speed printing.

[0026] The ink may contain organic solvents other than the organic solvent A exemplified above, either singly or in combination. However, it is preferable to adjust the content thereof to such an extent that the desired effect is not reduced. Specific examples of organic solvents other than organic solvent A include polyol solvents such as 1,2-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, and glycerin; monohydric alcohol solvents such as 2-propanol, 1-butanol, 2-butanol, 3-methoxy-1-butanol, and 3-methoxy-3-methylbutanol; propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, and tripropylene glycol. Propylene glycol monoether-based solvents such as cholesteryl ether, tripropylene glycol monopropyl ether, and tripropylene glycol monobutyl ether; propylene glycol diether-based solvents such as propylene glycol dimethyl ether, dipropylene glycol dimethyl ether, and tripropylene glycol dimethyl ether; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol-2-ethylhexyl ether, diethylene glycol monopentyl ether, diethylene glycol monohexyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, and triethylene glycol monobutyl ether;Examples include ethylene glycol diether solvents such as diethylene glycol methyl ethyl ether, diethylene glycol methyl butyl ether, triethylene glycol methyl ethyl ether, triethylene glycol methyl butyl ether, diethylene glycol diethyl ether, triethylene glycol diethyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol methyl ethyl ether, and tetraethylene glycol methyl butyl ether; and nitrogen-containing solvents such as 2-pyrrolidone, N-methyloxazolidinone, and ε-caprolactone. However, the solvent is not limited to these, as long as it does not satisfy the conditions of the organic solvent A above.

[0027] For the same reasons as in the case of organic solvent A, it is preferable that organic solvents other than organic solvent A also contain an alkanediol having 4 or more carbon atoms. Among the compounds exemplified above, examples of alkanediols having 4 or more carbon atoms include 1,2-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, and 1,6-hexanediol.

[0028] From the viewpoint of improving the wetting and spreading of the ink on non- or poorly ink-absorbent media, drying properties, and print image quality, the content of organic solvents other than the organic solvent A is preferably 0.1 to 10% by weight or less, more preferably 0.5 to 9%, and most preferably 1 to 8%.

[0029] The ink may further contain ink preparation agents in addition to the above components, such as water, polymer dispersants, resin emulsions, viscosity modifiers, surfactants, preservatives, antifungal agents, pH adjusters, chelating agents, rust inhibitors, water-soluble ultraviolet absorbers, antioxidants, and antifoaming agents.

[0030] [water] The ink composition may contain water. The water is preferably water with a low content of impurities such as metal ions, i.e., ion-exchanged water, distilled water, etc. Such water can be prepared by known methods. The content of water in the ink is preferably 55% to 90% by mass, more preferably 60% to 85% by mass.

[0031] [Polymer dispersant] The ink preferably contains one or more polymeric dispersants to disperse the colorant. In this specification, the polymeric dispersant may be abbreviated as "dispersant." Another embodiment of the present invention involves using a self-dispersing colorant as the colorant, thereby dispersing the colorant without using a dispersant. The dispersant is not particularly limited, and known dispersants such as polymeric dispersants can be used. Examples of polymeric dispersants include those other than the binders and waxes mentioned above, such as copolymers composed of at least two monomers (preferably, at least one of which is a hydrophilic monomer) selected from the group consisting of styrene and its derivatives; vinylnaphthalene and its derivatives; aliphatic alcohol esters of α,β-ethylenically unsaturated carboxylic acids; (meth)acrylic acid and its derivatives; maleic acid and its derivatives; itaconic acid and its derivatives; faric acid and its derivatives; vinyl acetate, vinyl alcohol, vinylpyrrolidone, acrylamide, and their derivatives. Examples of such copolymers include styrene-(meth)acrylic acid copolymers, styrene-(meth)acrylic acid-(meth)acrylic acid ester copolymers, (meth)acrylic acid ester-(meth)acrylic acid copolymers, polyethylene glycol (meth)acrylate-(meth)acrylic acid copolymers, and styrene-maleic acid copolymers. Among these, styrene-(meth)acrylic acid copolymers, styrene-(meth)acrylic acid-(meth)acrylic acid ester copolymers, and (meth)acrylic acid ester-(meth)acrylic acid copolymers are preferred, (meth)acrylic acid ester-(meth)acrylic acid copolymers are more preferred, and methacrylic acid ester-methacrylic acid copolymers are even more preferred. Examples of types of copolymers include block copolymers, random copolymers, and graft copolymers. These copolymers may be in the form of a salt.

[0032] Dispersants can be commercially available or synthesized.

[0033] Examples of commercially available dispersants include Joncyrl 62, 67, 68, 678, and 687 (styrene-acrylic copolymers manufactured by BASF); Movinyl S-100A (modified vinyl acetate copolymer manufactured by Japan Coating Resins Co., Ltd.); and Jurymer AT-210 (polyacrylic acid ester copolymer manufactured by Toa Gosei Co., Ltd.).

[0034] Examples of dispersants obtained by synthesis include the AB block polymer disclosed in WO 2013 / 115071. The monomer constituting the A block of the AB block polymer disclosed in WO 2013 / 115071 is at least one monomer selected from (meth)acrylic acid and linear or branched C4 alkyl (meth)acrylates, preferably at least one monomer selected from methacrylic acid and n-butyl methacrylate, and more preferably a combination of these two monomers. Furthermore, the monomer constituting the B block of the AB block polymer disclosed in WO 2013 / 115071 is at least one monomer selected from benzyl methacrylate and benzyl acrylate, preferably benzyl methacrylate. Specific examples of AB block polymers include the block copolymers disclosed in Synthesis Examples 3 to 8 of WO 2013 / 115071.

[0035] The acid value of the dispersant is usually 90 to 200 mgKOH / g, preferably 100 to 150 mgKOH / g, and more preferably 100 to 120 mgKOH / g.

[0036] A neutralizing agent may be used to uniformly disperse the dispersant in water. Examples of neutralizing agents include ammonia, alkali metal hydroxides, alkaline earth metal hydroxides, aliphatic amine compounds, and alkanolamine compounds. Among these, ammonia and alkali metal hydroxides are preferred, and ammonia is more preferred. The amount of neutralizing agent used is typically 30 to 300% neutralization, preferably 50 to 200%, with 100% neutralization being defined as neutralization with the theoretical equivalent of the acid value of the dispersant.

[0037] The mass-average molecular weight of the dispersant is usually 10,000 to 60,000, preferably 10,000 to 40,000, more preferably 15,000 to 30,000, and even more preferably 20,000 to 25,000. The mass-average molecular weight of the dispersant can be measured by gel permeation chromatography (GPC). Specifically, the measurement can be performed using an HLC-8320GPC (manufactured by Tosoh Corporation) as the GPC device, two TSK gel Super Multipore HZ-H columns (manufactured by Tosoh Corporation, inner diameter 4.6 mm × 15 cm), tetrahydrofuran as the eluent, and TSK Standard (manufactured by Tosoh Corporation) as the standard sample.

[0038] The PDI (mass average molecular weight / number average molecular weight) of the dispersant is preferably about 1.29 to 1.49. By setting the PDI within this range, the dispersibility and storage stability of the ink tend to be improved.

[0039] The dispersant can be used in a state where it is mixed with the colorant, or in a state where the surface of the colorant is partially or entirely coated with the dispersant, or both of these states can be used in combination.

[0040] In the ink, the ratio of the total mass of colorants to the total mass of dispersants is preferably 0.01 to 1.0, more preferably 0.05 to 0.6, and even more preferably 0.1 to 0.5, as calculated by Dy / Ds, where Dy is the total mass of colorants and Ds is the total mass of dispersants.

[0041] The resin emulsion is not particularly limited as long as it is one other than the wax and polymer dispersant. The resin emulsion preferably has an acid value of less than 10 mgKOH / g. By including a resin emulsion with an acid value of less than 10 mgKOH / g in the ink composition, the ink viscosity can be kept within a suitable range, resulting in a printed image with minimal graininess. Resin emulsions with an acid value exceeding 10 mgKOH / g significantly increase the ink viscosity upon evaporation of water, which inhibits the ink from spreading after landing on the media, making it difficult to achieve uniform solid print quality. The resin emulsion preferably contains one or more selected from polymers and waxes. The method for preparing the resin emulsion is not particularly limited. Examples include a method of mechanically micronizing and dispersing a resin in an aqueous medium; and a method of preparing a resin emulsion by emulsion polymerization, dispersion polymerization, suspension polymerization, or the like. Emulsion polymerization can be carried out using an emulsifier or in a soap-free manner. Examples of methods for preparing the resin emulsion include the method disclosed in Production Example 1 of JP-A No. 2000-336292. The resin content of the resin emulsion is preferably 20 to 50%. Examples of resin emulsions include urethane-based, polyester-based, acrylic-based, vinyl acetate-based, vinyl chloride-based, styrene-acrylic-based, acrylic-silicone-based, and styrene-butadiene-based polymers, or emulsions containing the same. Among these, resin emulsions selected from urethane-based, acrylic-based, and styrene-butadiene-based are preferred, and acrylic resin emulsions are more preferred. Examples of commercially available products include urethane polymers such as U-coat UX-320 (acid value: 10) manufactured by Sanyo Chemical Industry Co., Ltd., and WBR-016U (acid value: 7) and WBR-2101 (acid value: 10) manufactured by Taisei Fine Chemical Co., Ltd., polyester polymers such as Vylonal MD-1480 (acid value: 3), Vylonal MD-1985 (acid value: 2), and Vylonal MD-2000 (acid value: 2) manufactured by Toyobo Co., Ltd., and vinyl acetate polymers such as Vinyblan 715 (acid value: 8) and Vinyblan 985 (acid value: 5) manufactured by Nissin Chemical Industry Co., Ltd.

[0042] When the ink contains the resin emulsion, the content of the resin emulsion in the ink composition is preferably 0.2 to 10%, and more preferably 0.5 to 8%.

[0043] The ink may contain a viscosity modifier. In particular, the viscosity range of ink that can be ejected from an industrial inkjet printer is usually determined based on the specifications of the printer head (the head that ejects the ink) installed in the printer. Therefore, a viscosity modifier can be added to the ink to adjust the viscosity to an appropriate range. The viscosity modifier is not particularly limited as long as it is a substance that can adjust the viscosity of the ink, and known substances can be used. Specific examples include the organic solvents, polymer dispersants, and resin emulsions listed above.

[0044] The ink may contain a surfactant. The surfactant is not particularly limited, but examples thereof include anionic, cationic, nonionic, silicon-based, and fluorine-based surfactants. Cationic and nonionic surfactants are preferably used as the surfactant.

[0045] Examples of anionic surfactants include alkyl sulfocarboxylates, α-olefin sulfonates, polyoxyethylene alkyl ether acetates, polyoxyethylene alkyl ether sulfates, N-acylamino acids or salts thereof, N-acylmethyl taurines, alkyl sulfates, polyoxyalkyl ether sulfates, alkyl sulfates, polyoxyethylene alkyl ether phosphates, rosin acid soaps, castor oil sulfates, lauryl alcohol sulfates, alkylphenol phosphates, alkyl phosphates, alkylaryl sulfonates, diethyl sulfosuccinates, diethylhexyl sulfosuccinates, and dioctyl sulfosuccinates.

[0046] Examples of cationic surfactants include 2-vinylpyridine derivatives and poly(4-vinylpyridine) derivatives.

[0047] Examples of nonionic surfactants include polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene alkyl ethers having 4 to 18 carbon atoms (e.g., polyoxyethylene butyl ether, polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene 2-ethylhexyl ether), polyoxyethylene (di)styrenated phenyl ether (e.g., Emulgen manufactured by Kao Corporation), and polyoxyethylene (di)styrenated phenyl ether (e.g., Emulgen manufactured by Kao Corporation). ether-based surfactants such as A-60, A-90, A-500, and DSP-9, DSP-12.5, TSP-7.5, KTSP-16, and TSP-50 manufactured by Aoki Oil Co., Ltd.; ester-based surfactants such as polyoxyethylene oleate, polyoxyethylene distearate, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, polyoxyethylene monooleate, and polyoxyethylene stearate; acetylene glycol (or acetylene alcohol)-based surfactants such as 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, and 3,5-dimethyl-1-hexyn-3-ol (for example, Surfynol 420, 440, 465, and 485 manufactured by Evonik Japan Co., Ltd., and Olfine); STG, E1004, E1040, etc.); polyglycol ethers, etc.

[0048] Examples of silicone surfactants include polyether-modified siloxanes and polyether-modified polydimethylsiloxanes, such as Dynol 960 and 980 manufactured by Air Products Co., Ltd., Silface SAG001, SAG002, SAG003, SAG005, SAG503A, SAG008, SAG009, and SAG010 manufactured by Nissin Chemical Industry Co., Ltd., and BYK-345, 347, 348, 349, 3450, 3451, and 3455 manufactured by BYK Additives & Instruments, and TEGO Twin 4000, TEGO Wet KL 245, 250, 260, 265, 270, and 280 manufactured by Evonic Tego Chemie.

[0049] Examples of fluorine-based surfactants include perfluoroalkyl sulfonic acid compounds, perfluoroalkyl carboxylic acid compounds, perfluoroalkyl phosphate ester compounds, perfluoroalkyl ethylene oxide adducts, and polyoxyalkylene ether polymer compounds having perfluoroalkyl ether groups on the side chains. Specific examples of commercially available surfactants include Capstone FS-30 and FS-31 (manufactured by Chemours).

[0050] Examples of the preservatives include organic sulfur compounds, organic nitrogen sulfur compounds, organic halogen compounds, haloarylsulfone compounds, iodopropargyl compounds, haloalkylthio compounds, nitrile compounds, pyridine compounds, 8-oxyquinolines, benzothiazole compounds, isothiazolinone compounds, dithiols, pyridine oxide compounds, nitropropane compounds, organic tin compounds, phenol compounds, quaternary ammonium salt compounds, triazine compounds, thiazine compounds, anilides, adamantane compounds, dithiocarbamates, brominated indanone compounds, benzyl bromoacetate compounds, and inorganic salt compounds. Specific examples of commercially available preservatives include Proxel GXL(S) and XL-2(S) manufactured by Arch Chemicals.

[0051] Examples of the antifungal agent include sodium dehydroacetate, sodium benzoate, sodium pyridinethione-1-oxide, p-hydroxybenzoic acid ethyl ester, and 1,2-benzisothiazolin-3-one, as well as salts thereof.

[0052] Examples of the pH adjuster include alkanolamines such as diethanolamine, triethanolamine, and N-methyldiethanolamine; alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; ammonium hydroxide (aqueous ammonia); alkali metal carbonates such as lithium carbonate, sodium carbonate, sodium bicarbonate, and potassium carbonate; alkali metal salts of organic acids such as sodium silicate and potassium acetate; and inorganic bases such as disodium phosphate.

[0053] The pH of the ink is usually 5 to 11, preferably 6 to 9. The surface tension of the ink is usually 20 to 60 mN / m, preferably 25 to 50 mN / m. The viscosity of the ink is usually 2 to 30 mPa s, preferably 3 to 15 mPa s. The pH and surface tension of the ink can be adjusted by using a pH adjuster, a surfactant, an organic solvent, etc.

[0054] Examples of the chelating agent include disodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, sodium uracildiacetate, α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin.

[0055] Examples of the rust inhibitor include acid sulfite, sodium thiosulfate, ammonium thioglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.

[0056] Examples of the water-soluble ultraviolet absorber include sulfonated benzophenone compounds, benzotriazole compounds, salicylic acid compounds, cinnamic acid compounds, and triazine compounds.

[0057] Examples of the antioxidant include various organic and metal complex anti-fading agents, such as hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines, ascorbic acid, isoascorbic acid, chlorogenic acid, sulfur dioxide, catechins, dibutylhydroxytoluene, tocopherol, and butylhydroxyanisole.

[0058] Examples of the defoaming agents include acetylene-based defoaming agents such as the Surfynol 104 series (104A, 104E, 104H, 104PA, 104PG-50), Surfynol DF110D, Surfynol AD01, and Surfynol MD-20; Surfynol DF-58, BYK-017, BYK-018, BYK-019, BYK-021, BYK-022, BYK-023, BYK-024, BYK-025, BYK-028, BYK-044, BYK-092, BYK-1610, BYK-1611, and BYK-1622; Examples of suitable defoaming agents include silicone-based defoamers such as BYK-1615, BYK-1617, BYK-1650, BYK1679, BYK-1719, BYK-1723, BYK-1724, BYK-1730, BYK-1770, BYK-1781, BYK-1786, and BYK-1789; mineral oil-based defoamers such as BYK-035, BYK-037, BYK-038, and BYK-1630; higher alcohol derivatives such as Bisform CS, Bisform ECC, and Bisform TDI-1; and fatty acid derivatives such as Bisform TS-10. The defoaming agent is preferably an acetylene-based or silicone-based defoaming agent, and preferably DF-58.

[0059] The ink can be used in various printing applications, such as writing instruments, various printing applications, information printing, and textile printing, and is particularly preferably used in inkjet printing.

[0060] The ink can be prepared by any known method, including, for example, a method of preparing the ink by adding water and, if necessary, ink preparation agents to an aqueous dispersion prepared from a pigment and a wax, and mixing the mixture.

[0061] The ink can be prepared using a conventionally known apparatus, such as a ball mill, a sand mill, an attritor, a basket mill, a roll mill, etc. During preparation, it is preferable to remove coarse particles using a membrane filter, a mesh filter, etc.

[0062] The ink is preferably microfiltered. When microfiltering, a membrane filter and / or glass filter paper can be used. The pore size of the filter used for microfiltration is usually 0.5 μm to 20 μm, preferably 0.5 μm to 10 μm.

[0063] The present invention also includes a method for producing a water-based inkjet ink print using an ink set containing at least the ink. Examples of the ink set include an ink set containing two or more of the above inks, an ink set containing one or more of the above inks and one or more of other inks other than the above inks, etc. The other inks other than the above inks are not particularly limited as long as they have a different composition from the above inks, but it is preferable that they have a different hue from the above inks.

[0064] The method for producing a water-based inkjet ink print of the present invention includes a line-pass type inkjet printing apparatus having a circulation means for circulating ink from an outlet flow path of a head to an inlet flow path using a diaphragm pump.

[0065] [Method of manufacturing water-based inkjet ink prints] It is preferable that a printed item using the aqueous inkjet ink of the present invention is produced by a method comprising the steps of applying the ink onto a recording medium transported at a speed of 10 m / min or more by a line-pass type inkjet printing method while circulating the ink, and applying thermal energy to the recording medium to dry the ink.

[0066] [Line pass type inkjet device] The method for producing a printed matter using the water-based inkjet ink includes a line-pass type inkjet head printing device. A common method for printing with inkjet ink is to eject ink from the nozzles of an inkjet head and deposit ink droplets onto a recording medium. Inkjet printers equipped with such inkjet heads and used for printing can be broadly classified into two types depending on the printing method. One is the "scan type," in which the head moves back and forth over the recording medium while ejecting ink. The other is the "line pass type," in which the position of the head that ejects ink is fixed, and ink is ejected as the recording medium passes under the head. Line-pass types are capable of faster printing than scan types, and are expected to replace existing high-speed printers such as offset printers. However, depending on the image being printed, line-pass types can have nozzles that do not eject ink for long periods of time, making them more susceptible to ejection defects than scan types. As such, achieving both faster printing speeds and stable ejection is an important issue, especially for line-pass type printers. In recent years, the use of roll paper has increased as inkjet printing speeds have increased. When the printed surface is quickly turned over after the drying process in inkjet printing equipment, the ink on the printed surface can adhere to the reversing roller. To solve this problem, ink that dries quickly and is resistant to friction is highly desirable. In the above manufacturing method, in order to solve the above problems, it is preferable to use the above line-pass type inkjet device.

[0067] [Circulation means] The manufacturing method includes a circulation means for circulating the ink from the outlet flow path to the inlet flow path of the head. The head has nozzles for ejecting ink, inlet channels for introducing ink into the individual liquid chambers, and outlet channels for discharging ink from the individual liquid chambers. It is preferable that the head is connected to an ink supply unit for supplying ink to the individual liquid chambers via the inlet channels. The circulation means preferably connects the outflow channel to an ink supply unit, thereby circulating the ink between the ink ejection head and the ink supply unit. The ink ejection head can eject the ink after the circulation means has circulated the ink and then stopped the circulation, or can eject the ink while the circulation means is constantly circulating the ink. The circulation means is not particularly limited and can be selected appropriately depending on the purpose, and examples include circulation that includes liquid transfer using a diaphragm pump.

[0068] [Diaphragm pump] The line pass type ink jet device is equipped with a diaphragm pump. Generally, types of liquid delivery pumps include turbo (non-positive displacement) pumps, positive displacement pumps, and special pumps. However, since the present invention requires metering, a positive displacement pump is preferred. Examples of positive displacement pumps include piston pumps, plunger pumps, diaphragm pumps, gear pumps, vane pumps, screw pumps, syringe pumps, and tube pumps. To ensure stable ink ejection in inkjet printing, a metering pump is desirable because it stably supplies a constant amount of ink. Furthermore, in addition to being able to deliver a constant amount of liquid, it is also important that the amount of liquid delivered can be varied, accurate on / off control can be achieved, and the pump can be coordinated with a companion pump. For this reason, the diaphragm pump is essential in the above manufacturing method. Examples of diaphragm pumps include commercially available pumps manufactured by KNF, THOMAS, TACMINA, etc. It is desirable to select a diaphragm pump taking into consideration the ink ejection volume and circulation flow rate of the inkjet head and the maximum liquid delivery flow rate of the diaphragm pump. The circulation flow rate of the ink is greater than 0% and not more than 30% of the maximum flow rate of the diaphragm pump, preferably greater than 0% and not more than 20%, more preferably greater than 0% and not more than 15%, even more preferably greater than 1% and not more than 14%, and particularly preferably greater than 1% and not more than 13.5%.

[0069] In the above production method, the printing speed is preferably 10 m / min or more, more preferably 30 m / min or more, and particularly preferably 50 m / min or more.

[0070] After the ink is applied to the recording medium, it is preferable to apply thermal energy to the recording medium to dry the ink. There are no particular limitations on the method for applying the thermal energy, and examples include heat drying, hot air drying, infrared (IR) drying, microwave drying, and drum drying. The above drying methods may be used alone or in combination.

[0071] Among these, from the viewpoint of preventing damage to the recording medium and bumping of the water-soluble organic solvent in the ink, it is preferable to adopt the infrared drying method, which dries the recording medium by irradiating it with infrared rays. In this case, it is preferable that 50% or more of the integrated value of the total output of the infrared rays used for the infrared irradiation is present in the wavelength range of 700 nm to 1500 nm. Furthermore, from the viewpoint of removing vapor of the liquid component generated by the infrared irradiation and drying and further improving drying properties, it is preferable to create an air flow near the surface of the recording medium during infrared drying.

[0072] In the above manufacturing method, the material to be printed with the ink is a recording medium. The recording medium is not particularly limited as long as it is a material to which the ink can be attached, and examples of the recording medium include paper, film, fibers and cloth (cellulose, nylon, wool, etc.), leather, and color filter substrates. Recording media can be broadly divided into those with and without ink-receiving layers. Recording media with ink-receiving layers are commonly referred to as inkjet paper, inkjet film, glossy paper, etc. Representative commercially available products include Professional Photo Paper, Super Photo Paper, Glossy Gold, and Matte Photo Paper manufactured by Canon Inc.; Crispia (high gloss), Photo Paper (glossy), and Photo Matte Paper manufactured by Seiko Epson Corporation; Advanced Photo Paper (glossy) manufactured by Hewlett-Packard Japan; and Gasai Photo Finishing Pro manufactured by Fujifilm Corporation. Recording media without ink-receiving layers include various types of paper, such as coated paper and art paper, used in applications such as gravure printing and offset printing; and cast-coated paper used for label printing. The above inks can be suitably used on recording media without ink-receiving layers. When a recording medium without an ink receiving layer is used, it is also preferable to subject the recording medium to a surface modification treatment in order to improve the fixation of the colorant. Examples of the surface modification treatment include known methods such as corona discharge treatment, plasma treatment, and flame treatment.

[0073] The above-mentioned production method can provide printed matter that is excellent in ejection stability, mechanical stability, drying property, and abrasion resistance, and can also provide printed matter that is excellent in color development, gloss, graininess, and image quality. In addition, from the viewpoint of production, the method also provides excellent ink storage stability and image quality stability of printed matter. [Example]

[0074] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples. The "water" used in the examples is ion-exchanged water. The reactive emulsifier used in the examples is an ammonium salt of a sulfate ester of an oxirane polyadduct of {a reaction product of a C10-C14 branched alkanol and 1-(allyloxy)-2,3-epoxypropane}, mainly composed of {α-[2-(allyloxy)-1-({C10-C14 alkyloxy}methyl)ethyl]-ω-hydroxypoly(n=1-100)(oxyethylene)}}.

[0075] [Preparation Example 1]: Preparation of cyan pigment dispersion. A block copolymer was prepared as described in Synthesis Example 3 of WO 2013 / 115071. The resulting block copolymer (6 parts) was dissolved in 20 parts of methyl ethyl ketone to obtain a homogeneous solution. A mixture of sodium hydroxide (0.45 parts) and water (53.55 parts) was added to the resulting solution, followed by 20 parts of CI Pigment Blue 15:4 (Chromofine Blue 4851, manufactured by Dainichiseika Color & Chemicals Co., Ltd.). The mixture was dispersed in a sand grinder at 1500 rpm for 15 hours to obtain a liquid. Water (100 parts) was added to the resulting solution, and the solution was filtered through a GA-100 glass filter to remove aggregates and obtain a filtrate. The methyl ethyl ketone and a portion of the water in the filtrate were distilled under reduced pressure using an evaporator to obtain a cyan dispersion with a pigment content of 12.0%. The resulting pigment dispersion was designated "DP1."

[0076] [Preparation Example 2]: Preparation of magenta pigment dispersion. Dispersion 2 (DP2) was obtained in the same manner as in Preparation Example 1, except that inkjet Magetna E-02 (a solid solution pigment of CI Pigment Red 122 and CI Pigment Violet 19) manufactured by Heubach Color Japan Co., Ltd. was used instead of the CI Pigment Blue 15:4. The pigment concentration of DP2 was also adjusted to 12.0%.

[0077] [Preparation Example 3: Preparation of polymer emulsion] A glass reaction vessel (volume 3 L) was charged with water (100 parts), ammonium persulfate (0.3 parts), and a reactive emulsifier (1 part) to obtain a liquid. The air inside the reaction vessel was replaced with nitrogen, and the temperature of the liquid was raised to 70°C. A liquid consisting of water (120 parts), a reactive emulsifier (0.9 parts), methacrylic acid (2 parts), methyl methacrylate (37 parts), 2-ethylhexyl acrylate (59 parts), and allyl methacrylate (2 parts) was added dropwise to the liquid over a period of 3 hours. During the dropwise addition, the liquid temperature was maintained at 70°C while nitrogen was introduced. After the dropwise addition was completed, the reaction was continued for another 2 hours at 70°C and then cooled to 40°C. Triethanolamine (3.1 parts) was added to the resulting liquid to obtain an emulsion of polymer resin 1 as a white suspension with a solids content of 25%. The resulting emulsion of polymer resin 1 is designated "PEM1." The acid value of the obtained polymer resin 1 was 13 KOHmg / g and the glass transition point was -10°C.

[0078] [Preparation Example 4: Preparation of C ink and M ink] The dispersions "DP1," "DP2," and "PM1" obtained above were mixed with the components listed in Tables 1 and 2 below to obtain inks, which were then filtered through a 3 μm membrane filter to obtain C ink and M inks 1 to 4 for evaluation tests. The numbers in the columns for each component in Tables 1 and 2 indicate the amount (parts) used of that component. The abbreviations in Tables 1 and 2 are as follows: DP1: Cyan pigment dispersion obtained in Preparation Example 1 DP2: Magenta pigment dispersion obtained in Preparation Example 2 PM1: Polymer emulsion obtained in Preparation Example 3 PG: Propylene glycol 12HD: 1,2-hexanediol BYK-349 (a silicone surfactant manufactured by BYK Japan) AQUACER 515 (polyethylene wax emulsion manufactured by BYK Japan, solid content 35%)

[0079] [Table 1]

[0080] [Table 2]

[0081] [Evaluation of mechanical stability] A circulation path was set using each M ink, diaphragm pump (manufactured by KNF) and circulation flow rate combination shown in Table 3 below, and the ink was circulated for 200 cycles in a water bath at 35°C. A vacuum filtration test was performed using a metal filter (filtration accuracy 10 μm) using 50 g of ink before and after 100 cycles of circulation. The rate of change in ink filtration speed before and after circulation was evaluated according to the following criteria. The evaluation results are shown in Table 3. [Evaluation criteria] A: The change in ink filtration speed before and after circulation is less than 10% B: The change in ink filtration speed before and after circulation is 10% or more and less than 30% C: The ink filtration speed change rate before and after circulation is 30% or more and less than 60% D: The ink filtration speed change rate before and after circulation is 60% or more.

[0082] [Quick-drying rating] C ink and M inks 1 to 4 were printed on a line pass type printer equipped with a Kyocera Corporation KJ4B series recirculating inkjet head (1200 dpi x 1200 dpi) at a droplet size of 3 pl and a speed of 100 m / min, with Oji Paper Co., Ltd. OK top coat + 127.9 g / m 2 Inkjet recording was carried out on coated paper. The line-pass type inkjet printing device circulated the ink from the outflow passage to the inflow passage of the head using a diaphragm pump manufactured by KNF. Inkjet printing was performed by overlapping 100% duty cyan and 100% duty magenta to form a 200% duty mixed blue image, and the resulting image was dried at room temperature for 90 seconds and used as a test piece to evaluate quick-drying properties. The quick-drying property of each test piece was evaluated using a heat press machine model 728 manufactured by INSTA. That is, the test piece and a white paper with OK Top Coat+ were placed on top of each other and pressed with the heat press machine at 6 kg / cm. A pressure of 0.59 MPa was applied for 2 x 30 seconds. The OK Topcoat+ white paper was then peeled off from the test piece, and the degree of ink transfer to the white paper was evaluated using the following four-point evaluation standard. The evaluation results are shown in Table 3. [Evaluation criteria] A: No ink transfer was observed on the white paper. B: Slight ink transfer to the white paper is visible C: Ink transfer to white paper is visible D: Very large ink transfer to white paper

[0083] [Table 3]

[0084] [Dischargeability after being left open] M inks 1 to 4 were combined in the same manner as in Examples 1 to 5 above, and the "ejection properties after being left open" were evaluated. Specifically, M inks 1 to 4 were printed using a line pass type printer equipped with a Kyocera Corporation KJ4B series circulating inkjet head (1200 dpi x 1200 dpi) at a droplet size of 3 pL and a speed of 100 m / min on Oji Paper Co., Ltd. OK Topcoat + 127.9 g / m 2 Inkjet recording was carried out on coated paper. The line-pass type inkjet printing device circulated the water-based inkjet ink from the outlet flow path to the inlet flow path of the head using a diaphragm pump manufactured by KNF. After filling the ink, the ejection performance of all the nozzles in the head was checked, and then the head was left uncapped for 60 minutes, after which the ejection performance of all the nozzles in the head was checked again. The ejection performance after being left open was evaluated according to the following criteria. The evaluation results are shown in Table 4. [Evaluation criteria] A: No nozzle discharge defects and good initial discharge performance B: No nozzle ejection failure, but initial ejection performance slightly worsens C: About half of the nozzles were defective, and initial discharge was poor. D: Most nozzles have ejection defects, and initial ejection performance is very poor.

[0085] [Abrasion resistance evaluation] M inks 1 to 4 were combined in the same manner as in Examples 1 to 5 above, and evaluated for "abrasion resistance." Specifically, M inks 1 to 4 were printed using a line pass type printer equipped with a Kyocera Corporation KJ4B series circulating inkjet head (1200 dpi x 1200 dpi) at a droplet size of 3 pL and a speed of 100 m / min on Oji Paper Co., Ltd. OK Topcoat + 127.9 g / m 2 Inkjet recording was carried out on coated paper. The line-pass type inkjet printing device circulated the water-based inkjet ink from the outlet flow path to the inlet flow path of the head using a diaphragm pump manufactured by KNF. The inkjet printing was carried out so as to obtain a 100% duty image, and after the obtained image was completely dried, it was used as a test piece and subjected to a scratch resistance test. The abrasion resistance of each test piece was evaluated using a Yasuda Seiki Seisakusho No. 428 Gakushin-type abrasion tester (friction tester type II). Specifically, the test piece was rubbed back and forth 13 times with a 500 g load applied, and the degree of image deterioration was evaluated using the following four-point scale. The evaluation results are shown in Table 4. [Evaluation criteria] A: No scratches were found on the recorded image. B: Slight scratches can be seen on the recorded image C: Scratches can be seen on the recorded image. D: The recorded image is very scratched

[0086] [Table 4]

[0087] The results in Tables 3 and 4 show that the manufacturing methods of the present invention are significantly superior to conventional methods in terms of ink mechanical stability and ink quick-drying performance, and also exhibit performance equal to or better than that of conventional methods. Furthermore, the manufacturing methods of the present invention are also found to provide excellent ink ejection properties after being left in the open air and excellent abrasion resistance of printed matter. [Industrial Applicability]

[0088] The method for producing an inkjet ink print of the present invention makes it possible to provide a print that is excellent in ejection stability and mechanical stability, as well as quick drying and abrasion resistance.

Claims

1. Using water-based inkjet ink containing pigments, organic solvents, and wax, and a line-pass type inkjet printing device, the line pass type inkjet printing apparatus has a diaphragm pump, and a circulation means for circulating the water-based inkjet ink from an outlet flow path of a head to an inlet flow path by the diaphragm pump; a circulation flow rate of the water-based inkjet ink exceeding 0% and not exceeding 30% of a maximum flow rate of the diaphragm pump.

2. 2. The method for producing a water-based inkjet ink printed matter according to claim 1, wherein the organic solvent contains at least one organic solvent having a surface tension of 30 to 50 mN / m and a boiling point of 180°C or higher at 1 atmosphere.

3. 3. The method for producing a water-based inkjet ink printed matter according to claim 1 or 2, wherein the content by mass of the organic solvent having a surface tension of 30 to 50 mN / m and a boiling point of 180°C or higher at 1 atmosphere is 15% by mass or less, relative to the total mass of the water-based inkjet ink.

Images