JP2023096217A - Aqueous ink set, printed matter and method for producing printed matter - Google Patents

Abstract

To provide an aqueous ink set and a printed matter which have good print quality without mixed color bleeding or color unevenness and impart excellent wet friction resistance to a printed matter when printing onto a non-permeable base material such as film base material.SOLUTION: There is provided an ink set which comprises a pretreatment solution (I), an inkjet ink (II) and an overcoat solution (III), wherein the pretreatment solution (I) contains a coagulant (A), the inkjet ink (II) contains a pigment, a pigment dispersion resin (B), a water-soluble organic solvent, a surfactant and water, the overcoat solution (III) contains an acrylic resin emulsion (C), wax particles (D) and water, the acrylic resin emulsion (C) has an acid value of 5 to 65 mgKOH/g, the wax particles (D) contains at least one selected from the group consisting of carnauba wax having a melting point of 80 to 90°C and montan wax having a melting point of 80 to 90°C.SELECTED DRAWING: None

Description

The present invention relates to a pretreatment liquid, an inkjet ink, an aqueous ink set including an overcoat liquid, a printed matter thereof, and a method for producing the same.

The digital printing method is spreading rapidly as printing lots become smaller and needs diversify. Since the digital printing method does not require a printing plate, it is possible to realize small-lot production, cost reduction, and downsizing of the printing apparatus.

The inkjet printing method, which is a type of digital printing method, is a method in which fine droplets of ink are ejected and landed on a recording medium from an inkjet head, and images and characters (hereinafter collectively referred to as "printed matter") are printed on the recording medium. It is a method of forming a Compared to other digital printing methods, it is superior in terms of size and cost of printing equipment, running cost during printing, ease of full-color printing, etc. In recent years, it is also being used in industrial printing applications.

There are many types of inks used in inkjet printing, including oil-based, solvent-based, active energy ray-curable, and water-based inks. So far, solvent-based and active energy ray-curable inks have been used for industrial printing applications. However, in recent years, the demand for water-based inks has been increasing from the viewpoint of consideration and countermeasures against harmfulness to the environment and people.

Moreover, in recent years, amid the demand for expanded applications of the inkjet printing method, in addition to industrial printing applications, there is a demand for expansion to packaging applications such as paper containers, labels, and packaging films. In that case, it has properties that can withstand practical use for low-permeability substrates such as coated paper and art paper, and non-permeable substrates such as polypropylene film and polyethylene terephthalate (PET) film. Formation of prints will be required.

Imaging onto a film substrate is essential when inkjet printing is used to produce flexible packaging materials. Existing water-based inks used in inkjet printing are for forming images on highly permeable substrates such as plain paper and special paper (e.g., glossy photo paper), and film substrates. When printing on a non-permeable substrate such as , the ink droplets do not penetrate the substrate at all after landing, so drying due to penetration does not occur, and color bleeding and color unevenness occur. Problems such as poor print quality and low resistance to friction due to the state in which the pigment, which is the coloring material, adheres to the surface of the base material occur.

Pretreatment liquids for impermeable substrates are known for the problem of impairing print image quality. In general, pretreatment liquids for water-based inkjet inks that form a layer (ink-receiving layer) that absorbs liquid components in the water-based inkjet ink and improves drying properties (see Patent Documents 1 and 2) and a coloring material A layer (ink aggregation layer) that prevents ink bleeding and color unevenness between droplets and improves print quality by intentionally aggregating the solid components contained in the water-based inkjet ink, such as resin and resin (patented References 3 and 4) are known. However, no matter which method is adopted, it is difficult to improve resistance to friction with the pretreatment liquid alone.

In order to address the problem of low resistance to friction, for example, Patent Documents 5 to 8 disclose that the use of a fixing resin in ink can provide a certain improvement in friction resistance. Document 9 discloses that high abrasion resistance can be obtained by providing an overcoat layer on the ink layer. I couldn't.

JP-A-2000-238422 JP-A-2000-335084 JP 2005-74655 A JP 2016-168782 A JP 2011-246632 A JP 2011-246634 A Japanese Patent Application Laid-Open No. 2007-270362 JP 2009-30014 A JP 2010-150453 A

The present invention has been made to solve the above problems, and its object is to provide good print quality without color mixture bleeding or color unevenness even in printing on impermeable substrates such as film substrates. 3. To provide a water-based ink set and a printed matter which impart excellent water-rubbing resistance to the printed matter.

In order to solve the above problems, the present inventors have conducted extensive studies, and as a result, flexible packaging printed matter produced using an acrylic resin emulsion with a specific acid value and an overcoat liquid containing wax particles with a specific melting point The inventors have found that the above problems can be satisfactorily solved, and completed the present invention.

That is, the present invention provides an ink set containing a pretreatment liquid (I), an inkjet ink (II), and an overcoat liquid (III), wherein the pretreatment liquid (I) contains the flocculant (A), The inkjet ink (II) contains a pigment, a pigment dispersion resin (B), a water-soluble organic solvent, a surfactant, and water, and the overcoat liquid (III) is an acrylic resin emulsion (C) and wax particles (D). , and water, the acrylic resin emulsion (C) has an acid value of 5 to 65 mgKOH/g, and the wax particles (D) contain carnauba wax having a melting point of 80 to 90° C. and An aqueous ink set containing at least one selected from the group consisting of montan waxes.

The present invention also relates to the water-based ink set, wherein the acrylic resin emulsion (C) has a glass transition temperature of 20 to 60°C.

The present invention also relates to the water-based ink set, wherein the wax particles (D) have an average particle size (D50) of 50 to 200 nm.

The present invention also relates to the aqueous ink set, wherein the overcoat liquid (III) contains a carbodiimide aqueous dispersion.

The present invention also relates to the water-based ink set, which is used for flexible packaging materials.

The present invention also relates to a water-based ink jet printed matter obtained by printing the water-based ink set on a recording medium.

The present invention also provides a method for producing a water-based inkjet ink printed matter using the above-described water-based ink set, comprising the step of applying pretreatment liquid (I) to a recording medium; , relates to a method for producing a water-based inkjet ink printed material, comprising a step of applying the inkjet ink (II) by a one-pass printing method and a step of applying the overcoat liquid (III).

When the ink set of the present invention is used for printing on a film substrate, the print image quality is good without color mixture bleeding or color unevenness, and high water abrasion resistance can be imparted to the printed matter.

The water-based ink set, which is an embodiment of the present invention, will be described below by citing preferred embodiments.

The pretreatment liquid (I) contained in the water-based ink set of the present invention contains a flocculant (A). The flocculant dissolves in the inkjet ink to form an image by flocculating and depositing the ink, and therefore dissolves in water. Therefore, it is difficult to develop water resistance, and the durability required for printed materials for flexible packaging cannot be obtained, resulting in poor appearance.

Therefore, as a result of intensive studies by the present inventors, a water-based ink set having a pretreatment liquid (I), an inkjet ink (II), and an overcoat liquid (III) on a film substrate, wherein the pretreatment The liquid (I) contains a flocculant (A), the inkjet ink (II) contains a pigment, a pigment dispersion resin (B), a water-soluble organic solvent, a surfactant, and water, and the overcoat liquid (III) contains an acrylic resin emulsion (C), wax particles (D), and water, the acrylic resin emulsion (C) has an acid value of 5 to 65 mgKOH/g, and the wax particles (D) are In a water-based ink set containing at least one selected from the group consisting of carnauba wax having a melting point of 80 to 90° C. and montan wax having a melting point of 80 to 90° C., there is no mixed color bleeding or color unevenness, and the print quality is good and excellent. It has been found that prints having water rubbing resistance can be obtained. Although the detailed mechanism is not clear, for example, the following is considered.

First, the role of each component in the water-based ink set of the present invention is as follows.
The role of the pretreatment liquid (I) is to assist the image formation of the water-based inkjet ink (II) to improve the print image quality, and to improve the adhesion to the film substrate. The mechanism is that the flocculant (A) contained in the pretreatment liquid (I) is a pigment dispersion resin (B) having a structure derived from an ethylenically unsaturated monomer containing an anionic group contained in the water-based inkjet ink. By coagulating and depositing, it is thought that mixed color bleeding and color unevenness caused by mixing of water-based inkjet ink droplets can be prevented.

In addition, the role of the overcoat liquid (III) in the water-based ink set of the present invention is to prevent direct contact between the layer composed of the pretreatment liquid (I) and the water-based inkjet ink (II) and water. , it is thought that the excellent water resistance is obtained by trapping the surplus flocculant (A) contained in the pretreatment liquid (I) layer to prevent penetration of moisture. With regard to the action between the flocculant (A) and the acrylic resin emulsion (C) in which the overcoat liquid (III) has an acid value of 5 to 65 mgKOH/g, when the flocculant (A) is an inorganic salt, In the case of chelate formation and cationic polymer compounds, this is considered to be the decrease in water solubility due to ionic bonding with the cationic polymer compound. In printing on flexible packaging materials, film substrates are susceptible to thermal changes, and the temperature of hot air generally used for drying is about 80°C. Part of the wax particles (D) selected from the group consisting of carnauba wax having a melting point of 80 to 90° C. and montan wax having a melting point of 80 to 90° C. protrude from the surface of the overcoat liquid (III) layer. Some of the wax particles (D) are melted by hot air for drying and spread over the surface of the overcoat liquid (III) layer. It is believed that the spread wax imparts high water repellency and slip properties to the surface of the coating film, resulting in a printed material with excellent water abrasion resistance.

As described above, the configuration of the water-based ink set of the present invention is essential in order to obtain a printed matter having good print quality without color mixture bleeding or color unevenness and having excellent water abrasion resistance necessary for flexible packaging printed matter. be.

Subsequently, each component constituting the water-based ink set of the present invention will be described in detail below.

<Pretreatment liquid (I)>
As described above, in the present invention, the pretreatment liquid (I) contains the flocculant (A).

<Flocculant (A)>
The purpose of the aggregating agent (A) used in the pretreatment liquid (I) used in the present invention is to aggregate and/or increase the viscosity of the components in the water-based inkjet ink to suppress color mixture bleeding and color unevenness and to obtain excellent print quality. used in Examples of the flocculant (A) include metal salts and cationic polymer compounds. Among them, it is preferable to use a metal salt, and it is particularly preferable to use a salt of one or more polyvalent metal ions selected from the group consisting of Ca ²⁺ , Mg ²⁺ , Zn ²⁺ and Al ³⁺ . When a metal salt is used as a flocculating agent, its content is preferably 2 to 25% by mass, particularly preferably 3 to 20% by mass, based on the total amount of the pretreatment liquid.
Only one type of flocculant may be used, or two or more types of flocculants may be mixed.

When a cationic polymer compound is contained as the flocculant (A) used in the present invention, it reduces the dispersing function of the pigment in the ink and has suitable solubility and diffusibility in the anchor liquid. It can be used arbitrarily. Moreover, one type may be used alone, or two or more types may be used in combination. Examples of cationic groups contained in cationic polymer compounds include, but are not limited to, amino groups, ammonium groups, amide groups, imino groups, hydrazino groups, and _--NHCONH2 groups. Among the above, the cationic polymer compound is preferably a compound containing one or more structural units selected from a diallylamine structural unit, a diallylammonium structural unit, and an epihalohydrin structural unit, and contains at least a diallylammonium structural unit. is more preferred. The content of the cationic polymer compound is preferably 1 to 20% by mass, more preferably 3 to 10% by mass, relative to the total amount of the pretreatment liquid.

When an organic acid is included as the flocculant (A) used in the present invention, a compound having a carboxyl group is suitable. Specific examples include malonic acid, succinic acid, citric acid, malic acid, tartaric acid, formic acid, acetic acid, propionic acid, and lactic acid. The content of the organic acid is preferably 1 to 12% by mass, more preferably 2 to 10% by mass, particularly preferably 3 to 8% by mass, relative to the total amount of the pretreatment liquid.

The pretreatment liquid (I) preferably contains a binder resin (excluding the cationic polymer compound) from the viewpoint of adhesion to the film substrate and strength of the anchor layer (I). Specifically, (meth)acrylic resins, styrene (meth)acrylic resins, urethane resins, urethane (meth)acrylic resins, polyester resins (polycondensates of polycarboxylic acids and polyhydric alcohols) , polyolefin-based resins, styrene-butadiene-based resins, vinyl chloride-based resins, and the like. These may be used alone, or two or more resins may be mixed. Moreover, the form of the resin to be used may be any of a water-soluble resin, a hydrosol which is a water-insoluble resin, and an emulsion. In the present invention, "(meth)acryl" represents acryl or methacryl. In the present invention, the "emulsion" is a form in which an emulsifier or a water-soluble polymer compound is adsorbed on the surface of resin fine particles and dispersed in a dispersion medium, and the 50% volume particle diameter measured by the method described later is 5 to 1000 nm.

When the pretreatment liquid (I) used in the present invention contains a resin, the blending amount thereof is 1 to 20% relative to the total amount of the pretreatment liquid (I), from the viewpoint of coatability and adhesive strength to the film substrate. % by mass is preferable, and 3 to 15% by mass is more preferable.

<Other ingredients>
In addition, a water-soluble organic solvent, a surfactant, a pH adjuster, an antifoaming agent, a thickener, an antiseptic, and the like can be appropriately added to the pretreatment liquid (I) used in the present invention.

<Inkjet ink (II)>
Next, the inkjet ink (II) constituting the present invention will be described. The inkjet ink (II) (hereinafter also simply referred to as "aqueous ink" or "ink") contains a pigment, a pigment dispersion resin (B), a water-soluble organic solvent, a surfactant, and water.

<Pigment>
As the pigment used in the inkjet ink (II) used in the present invention, both inorganic pigments and organic pigments can be used, and there is no particular limitation. Organic pigments include azo, phthalocyanine, anthraquinone, perylene, perinone, quinacridone, thioindigo, dioxazine, isoindoline, quinophthalone, azomethineazo, diketopyrrolopyrrole, and isoindoline pigments. pigments. Examples of inorganic pigments include carbon black, titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, red iron oxide, aluminum, and mica (mica). Titanium oxide is preferably titanium oxide surface-coated with at least silica or alumina. In addition, the C.I. I. Pigments described as pigments can optionally be used.

It is also preferable to use hollow resin particles as the white pigment. Hollow resin particles have a smaller specific gravity (apparent density) than titanium oxide or the like, and can easily suppress sedimentation over time, so that ink with excellent storage stability can be obtained.

These pigments may be used individually by 1 type, and may use 2 or more types together. Except for the case of white ink, the pigment is preferably contained in the range of 2% by mass to 20% by mass, more preferably 2.5% by mass to 15% by mass, based on the total amount of the ink. Preferably, it is particularly preferably contained in the range of 3% by mass or more and 10% by mass or less. In the case of white ink, the pigment content is preferably 5% by mass or more and 40% by mass or less, more preferably 8% by mass or more and 30% by mass or less, relative to the total amount of white ink. By setting the pigment content to 2% by mass or more (5% by mass or more in the case of white ink), it is possible to obtain sufficient color development (or concealability in the case of white ink) even in 1-pass printing. . Also, by setting the pigment content to 20% by mass or less (40% by mass or less in the case of white ink), the viscosity of the ink can be kept within a range suitable for inkjet printing.

<Pigment dispersion resin (B)>
As a method of stably dispersing and holding a pigment in an aqueous ink, (1) a method of adsorbing a pigment dispersing resin on the surface of the pigment to disperse it, and (2) a method of applying a water-soluble and/or water-dispersible surfactant to the surface of the pigment. (3) a method of chemically and physically introducing a hydrophilic functional group onto the surface of the pigment and dispersing it in the ink without a dispersing resin or surfactant (self-dispersion pigment); (4) water A method of coating a pigment with an insoluble resin and, if necessary, dispersing it in ink using another pigment dispersing resin or surfactant can be used.

In the water-based ink used in the present invention, the method (1) or (4) above, that is, the method using a pigment dispersion resin is selected, and the pigment dispersion resin (B) is an anion as a structural unit. By containing a structure derived from an ethylenically unsaturated monomer containing a group, in addition to ensuring solubility in water and water-soluble organic solvents, the flocculant instantly aggregates and / or thickens, resulting in color mixing bleeding and Color unevenness can be reduced and print quality can be particularly improved. Furthermore, it is preferable from the viewpoint that the viscosity of the pigment dispersion liquid can be suppressed because the dispersed state of the pigment is suitable. Further, the acid value of the pigment dispersion resin (B) is preferably from 30 to 375 mgKOH/g, more preferably from 65 to 350 mgKOH/g, and still more preferably from 100 to 300 mgKOH/g, since the above effects are more preferably exhibited. is g.

The type of the pigment dispersion resin is not particularly limited. Maleic acid-based resins, polyurethane-based resins, polyester-based resins, and the like can be used. Among them, (meth)acrylic resins, styrene (meth)acrylic resins, polyurethane resins, and polyester resins are particularly preferable in terms of material selectivity and ease of synthesis. Moreover, said pigment dispersion resin can be synthesized by a known method, or a commercially available product can be used. In the present invention, "(anhydride) maleic acid" represents maleic acid or maleic anhydride.

When a water-soluble pigment dispersing resin is used as the pigment dispersing resin (B) as a method for stably dispersing and holding the pigment in the water-based ink, in order to increase the solubility in the ink, Neutralization of acid groups with bases is preferred. However, if the base is added excessively, the flocculant (A) in the pretreatment liquid (I) will be neutralized, and a sufficient effect cannot be exhibited, so pay attention to the addition amount. There is a need. The pH of the inkjet ink (II) is preferably 7 to 11, more preferably 7.5 to 10.5, in order to sufficiently exhibit the function of the pretreatment liquid (I).

Bases for neutralizing the pigment dispersion resin (B) include alkanolamines such as diethanolamine, triethanolamine and N-methyldiethanolamine; ammonia water; alkalis such as lithium hydroxide, sodium hydroxide and potassium hydroxide. metal hydroxides; and alkali metal carbonates such as sodium carbonate, sodium hydrogencarbonate and potassium carbonate.

The weight average molecular weight of the pigment dispersion resin (B) is preferably in the range of 1,000 to 200,000, more preferably in the range of 5,000 to 100,000. When the weight-average molecular weight is within the above range, the pigment is stably dispersed in water, and the viscosity can be easily adjusted when applied to water-based ink.

In the present invention, the blending amount of the pigment dispersing resin (B) is preferably 1 to 50% by mass based on the pigment. By setting the amount of the pigment dispersion resin (B) to 1 to 50% by mass based on the pigment, the viscosity of the pigment dispersion is suppressed, and the viscosity stability and dispersion stability of the pigment dispersion and the inkjet ink (II) are improved. It is preferable because it improves the property and can cause rapid deterioration of the dispersing function when mixed with the pretreatment liquid. The amount of the pigment dispersing resin (B) blended with respect to the pigment is more preferably 2 to 45% by mass, still more preferably 3 to 40% by mass, and most preferably 4 to 35% by mass.

The pigment dispersion resin (B) used in the present invention contains, as a structural unit, a structure derived from an ethylenically unsaturated monomer containing an anionic group. The above-mentioned "anionic group" includes a carboxylic acid (carboxyl) group, a sulfonic acid group, a phosphonic acid group, and the like, and any of them may be selected in the present invention. Above all, in addition to ensuring solubility in water and water-soluble organic solvents and excellent dispersion stability, the flocculant instantly aggregates and / or thickens, reducing color bleeding and color unevenness, and particularly improving print quality. A carboxyl group is preferably selected from the viewpoint that it can be improved.

As the ethylenically unsaturated monomer containing an anionic group, a known one can be used. Specifically, acrylic acid, methacrylic acid, carboxymethyl (meth)acrylate, carboxyethyl (meth)acrylate, acryloyloxyethyl succinic acid, methacryloyloxyethyl succinic acid, acryloyloxyethyl phthalate, methacryloyloxyethyl phthalate, acryloyl Oxyisobutyric acid, methacryloyloxyisobutyric acid, 2-sulfoethyl (meth)acrylate, acryloyloxyethylphosphonic acid, methacryloyloxyethylphosphonic acid, 2-(phosphonooxy)ethyl (meth)acrylate, vinylsulfonic acid, styrenecarboxylic acid, styrenesulfone acid, styrene phosphonic acid, etc., but not limited thereto. These anionic group-containing ethylenically unsaturated monomers (b1) can be used singly or in combination. In the present invention, "(meth)acrylate" represents at least one selected from "acrylate" and "methacrylate".

<Water-soluble organic solvent>
The water-based ink set of the present invention contains a water-soluble organic solvent. The term "water-soluble organic solvent" as used herein refers to a solvent that has a solubility in water of 5 g/100 g H ₂ O or more at 25° C. and 1 atm and is liquid.
The water-soluble organic solvent is not particularly limited, and any known one can be used. From the viewpoint of compatibility and affinity with material components, it is preferable to contain a glycol ether-based solvent and/or an alkyl polyol-based solvent. Alkyl polyol solvents include 1,2-ethanediol (ethylene glycol), 1,2-propanediol (propylene glycol), 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 2,2-dimethyl-1,3-propanediol, 2-methyl-1,3-propane Diol, 2-ethyl-2-methyl-1,3-propanediol, 3-methyl-1,3-butanediol, 3-methyl-1,5-pentanediol, 2-methyl-2-propyl-1,3 -propanediol, 2-methylpentane-2,4-diol, 2-ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol and the like. Glycol ether solvents include diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, tetra Ethylene Glycol Monomethyl Ether, Tetraethylene Glycol Monobutyl Ether, Propylene Glycol Monomethyl Ether, Propylene Glycol Monoethyl Ether, Propylene Glycol Monopropyl Ether, Dipropylene Glycol Monomethyl Ether, Dipropylene Glycol Monopropyl Ether, Dipropylene Glycol Monobutyl Ether, Tripropylene Glycol Glycol monoalkyl ethers such as monomethyl ether and tripropylene glycol monobutyl ether; glycols such as diethylene glycol diethyl ether, diethylene glycol isopropyl methyl ether, diethylene glycol butyl methyl ether, triethylene glycol dimethyl ether, triethylene glycol butyl methyl ether, tetraethylene glycol dimethyl ether; Dialkyl ethers and the like can be mentioned.

One of these water-soluble organic solvents may be used alone, or two or more thereof may be used in combination. The water-soluble organic solvent is preferably 3% by mass or more and 40% by mass or less, more preferably 5% by mass or more and 35% by mass or less, and 8% by mass or more and 30% by mass or less with respect to the total amount of the ink. is particularly preferred. By setting the total amount of the water-soluble organic solvent to 3% by mass or more, the moisture retention property of the ink, the ejection stability, and the wettability of the water-based ink on the printing substrate are improved. Further, by setting the total content of the water-soluble organic solvent to 40% by mass or less, it is possible to obtain a printed material having good drying property and color bleeding, and good anti-blocking property.

<Surfactant>
The water-based inkjet ink (II) used in the present invention adjusts its surface tension, ensures wettability on the film substrate and pretreatment liquid layer (I), and improves print image quality. is preferably used. On the other hand, if the surface tension is too low, the nozzle surface of the inkjet head will be wetted with water-based ink, impairing ejection stability. From the viewpoint of ensuring optimal wettability and realizing stable ejection from the inkjet head, it is preferable to use a surfactant such as a siloxane-based, acetylene-based, acrylic, fluorine-based, or polyoxyalkylene alkyl ether-based surfactant. It is particularly preferred to use siloxane-based and/or acetylenic surfactants. The amount of the surfactant added is preferably 0.05% by mass or more and 5.0% by mass or less, more preferably 0.1% by mass or more and 3.0% by mass or less, relative to the total amount of the water-based inkjet ink (II). . By making it 0.05% by mass or more, the function of the surfactant can be sufficiently exhibited, and by making it 5.0% by mass or less, the storage stability and ejection stability of the water-based ink are suitable. level can be maintained.

<Other ingredients>
In addition, a binder resin, a pH adjuster, an antifoaming agent, a thickener, an antiseptic, and the like can be appropriately added to the inkjet ink (II) used in the present invention.

<Overcoat liquid (III)>
Next, the overcoat liquid (III) constituting the present invention will be described. The overcoat liquid (III) contains an acrylic resin emulsion (C), wax particles (D), and water.

<Acrylic resin emulsion (C)>
The acrylic resin emulsion (C) used in the overcoat liquid (III) used in the present invention is a direct reaction between the layer composed of the pretreatment liquid (I) and the water-based inkjet ink (II) and water. It is used for the purpose of obtaining excellent water resistance by preventing contact and by trapping excess flocculant (A) contained in the pretreatment liquid (I) layer to prevent penetration of moisture.

A water-soluble polymer compound can be used for synthesizing the acrylic resin emulsion (C) used in the present invention. When the water-soluble polymer compound is used in the shell portion of the acrylic resin emulsion (C), it functions as a polymer surfactant that copolymerizes the monomer used in the core portion. Therefore, it is possible to use an ethylenically unsaturated monomer containing an anionic group with moderate hydrophilicity and an ethylenically unsaturated monomer containing an aromatic ethylenically unsaturated monomer with moderate hydrophobicity. preferable.

A well-known thing can be used as said aromatic ethylenically unsaturated monomer. Specifically, styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, m-methylstyrene, vinylnaphthalene, benzyl acrylate, benzyl methacrylate, phenoxyethyl acrylate, phenoxyethyl methacrylate, phenoxydiethylene glycol acrylate, phenoxydiethylene glycol Examples include methacrylate, phenoxytetraethyleneglycol acrylate, phenoxytetraethyleneglycol methacrylate, phenoxyhexaethyleneglycol acrylate, phenoxyhexaethyleneglycol methacrylate, phenylacrylate, and phenylmethacrylate, but are not particularly limited thereto.

A well-known thing can be used as an ethylenic unsaturated monomer containing the said anionic group. Specifically, acrylic acid, methacrylic acid, carboxymethyl (meth)acrylate, carboxyethyl (meth)acrylate, acryloyloxyethyl succinic acid, methacryloyloxyethyl succinic acid, acryloyloxyethyl phthalate, methacryloyloxyethyl phthalate, acryloyl Oxyisobutyric acid, methacryloyloxyisobutyric acid, 2-sulfoethyl (meth)acrylate, acryloyloxyethylphosphonic acid, methacryloyloxyethylphosphonic acid, 2-(phosphonooxy)ethyl (meth)acrylate, vinylsulfonic acid, styrenecarboxylic acid, styrenesulfone acid, styrene phosphonic acid and the like. These anionic group-containing ethylenically unsaturated monomers can be used singly or in combination.

Other ethylenically unsaturated monomers can be used in the synthesis of the water-soluble polymer compound.

Known substances can be used as the other ethylenically unsaturated monomer. Specifically, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, pentyl (meth)acrylate, heptyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, Containing linear or branched alkyl groups such as octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, etc. an ethylenically unsaturated monomer;
Alicyclic alkyl group-containing ethylenically unsaturated monomers such as cyclohexyl (meth)acrylate and isobornyl (meth)acrylate;
(Meth)acrylamide, N-methoxymethyl-(meth)acrylamide, N-ethoxymethyl-(meth)acrylamide, N-propoxymethyl-(meth)acrylamide, N-butoxymethyl-(meth)acrylamide, N-pentoxymethyl -(meth)acrylamide, N,N-di(methoxymethyl)acrylamide, N-ethoxymethyl-N-methoxymethylmethacrylamide, N,N-di(ethoxymethyl)acrylamide, N-ethoxymethyl-N-propoxymethylmethacrylamide Acrylamide, N,N-di(propoxymethyl)acrylamide, N-butoxymethyl-N-(propoxymethyl)methacrylamide, N,N-di(butoxymethyl)acrylamide, N-butoxymethyl-N-(methoxymethyl)methacrylamide acrylamide, N,N-di(pentoxymethyl)acrylamide, N-methoxymethyl-N-(pentoxymethyl)methacrylamide, N,N-dimethylaminopropylacrylamide, N,N-diethylaminopropylacrylamide, N,N- Amide group-containing ethylenically unsaturated monomers such as dimethylacrylamide and N,N-diethylacrylamide;
2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, glycerol mono (meth)acrylate, 4-hydroxyvinylbenzene, 1-ethynyl-1-cyclohexanol, allyl hydroxyl group-containing ethylenically unsaturated monomers such as alcohol; and the like, but are not particularly limited thereto.

The water-soluble polymer compound contains 10% by mass to 70% by mass of an ethylenically unsaturated aromatic monomer in 100% by mass of the ethylenically unsaturated monomer, and an ethylenically unsaturated monomer containing an anionic group. It is preferred to copolymerize ethylenically unsaturated monomers containing 3% to 40% by weight of (b1). By using the ethylenically unsaturated monomer within these ranges, the adhesion between the pretreatment liquid layer (I) and the ink layer (II) can be further improved.

A known polymerization initiator can be used for the synthesis of the water-soluble polymer compound. It is preferable to use 0.1 to 10 parts by mass of the polymerization initiator with respect to 100 parts by mass of the ethylenically unsaturated monomer. In the case of synthesis by bulk polymerization, if the reaction temperature is raised to a high temperature, copolymerization may be possible without using a polymerization initiator.

The polymerization initiator is preferably an organic peroxide and an azo compound. Examples of the organic peroxide include benzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl hydroperoxide, tert-butyl peroxy (2-ethylhexanoate), tert-butyl peroxy-3,5 , 5-trimethylhexanoate, di-tert-butyl peroxide and the like. Examples of the azo compound include 2,2′-azobisisobutyronitrile, 2,2′-azobis-2,4-dimethylvaleronitrile, 2,2′-azobis(4-methoxy-2,4-dimethyl valeronitrile), 1,1'-azobis-cyclohexane-1-carbonitrile and the like, but are not particularly limited thereto.

The water-soluble polymer compound preferably has a weight average molecular weight of 5,000 to 30,000, more preferably 7,000 to 20,000. When the weight average molecular weight is in the range of 5,000 to 30,000, the adhesion between the pretreatment liquid layer (I) and the ink layer (II) can be further improved. Furthermore, the copolymerizability of the core portion can be improved. In addition, a weight average molecular weight means the value of polystyrene conversion by GPC (gel permeation chromatography) measurement.

The acrylic resin emulsion (C) used in the present invention is a resin obtained by emulsion polymerization of an ethylenically unsaturated monomer in the presence of a water-soluble polymer compound or a surfactant that serves as the shell portion of the core-shell emulsion. be. In particular, it may contain an ethylenically unsaturated monomer containing an ethylenically unsaturated monomer containing an alkyl group having 1 to 8 carbon atoms and an ethylenically unsaturated monomer containing an aromatic ethylenically unsaturated monomer. Preferably, the adhesion between the pretreatment liquid layer (I) and the ink layer (II) can be improved.

Examples of the alkyl group-containing ethylenically unsaturated monomer having 1 to 8 carbon atoms include methyl methacrylate, methyl acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl methacrylate, n-butyl acrylate, t -Butyl methacrylate, pentyl (meth)acrylate, heptyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, etc., but not limited to these .

Ethylenically unsaturated monomers including aromatic ethylenically unsaturated monomers include, for example, styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, m-methylstyrene, vinylnaphthalene, benzyl acrylate, benzyl methacrylate, phenoxyethyl acrylate, phenoxyethyl methacrylate, phenoxydiethylene glycol acrylate, phenoxydiethylene glycol methacrylate, phenoxytetraethyleneglycol acrylate, phenoxytetraethyleneglycol methacrylate, phenoxyhexaethyleneglycol acrylate, phenoxyhexaethyleneglycol methacrylate, phenylacrylate, phenylmethacrylate, etc. Examples include, but are not particularly limited to.

In the synthesis of the acrylic resin emulsion (C) used in the present invention, other ethylenically unsaturated monomers are used to adjust the balance between hydrophilicity and hydrophobicity, or to improve the stability of the emulsion. can be made

Said other ethylenically unsaturated monomers are, for example, alicyclic alkyl group-containing ethylenically unsaturated monomers such as cyclohexyl (meth)acrylate and isobornyl (meth)acrylate;
(Meth)acrylamide, N-methoxymethyl-(meth)acrylamide, N-ethoxymethyl-(meth)acrylamide, N-propoxymethyl-(meth)acrylamide, N-butoxymethyl-(meth)acrylamide, N-pentoxymethyl -(meth)acrylamide, N,N-di(methoxymethyl)acrylamide, N-ethoxymethyl-N-methoxymethylmethacrylamide, N,N-di(ethoxymethyl)acrylamide, N-ethoxymethyl-N-propoxymethylmethacrylamide Acrylamide, N,N-di(propoxymethyl)acrylamide, N-butoxymethyl-N-(propoxymethyl)methacrylamide, N,N-di(butoxymethyl)acrylamide, N-butoxymethyl-N-(methoxymethyl)methacrylamide acrylamide, N,N-di(pentoxymethyl)acrylamide, N-methoxymethyl-N-(pentoxymethyl)methacrylamide, N,N-dimethylaminopropylacrylamide, N,N-diethylaminopropylacrylamide, N,N- Amide group-containing ethylenically unsaturated monomers such as dimethylacrylamide and N,N-diethylacrylamide;
2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, glycerol mono (meth)acrylate, 4-hydroxyvinylbenzene, 1-ethynyl-1-cyclohexanol, allyl hydroxyl group-containing ethylenically unsaturated monomers such as alcohol;
Allyl (meth)acrylate, 1-methylallyl (meth)acrylate, 2-methylallyl (meth)acrylate, 1-butenyl (meth)acrylate, 2-butenyl (meth)acrylate, 3-butenyl (meth)acrylate, 1,3- Methyl-3-butenyl (meth)acrylate, 2-Chlorallyl (meth)acrylate, 3-Chlorallyl (meth)acrylate, o-Allylphenyl (meth)acrylate, 2-(allyloxy)ethyl (meth)acrylate, Allyllactyl (meth)acrylate Acrylate, citronellyl (meth)acrylate, geranyl (meth)acrylate, rhodinyl (meth)acrylate, cinnamyl (meth)acrylate, diallyl maleate, diallylitaconic acid, vinyl (meth)acrylate, vinyl crotonate, vinyl oleate, linolenic acid Vinyl, 2-(2'-vinyloxyethoxy)ethyl (meth)acrylate, ethylene glycol di(meth)acrylate, triethylene glycol (meth)acrylate, tetraethylene glycol (meth)acrylate, trimethylolpropane tri(meth)acrylate , pentaerythritol tri(meth)acrylate, 1,1,1-trishydroxymethylethane diacrylate, 1,1,1-trishydroxymethylethane triacrylate, 1,1,1-trishydroxymethylpropane triacrylate, divinylbenzene , ethylenically unsaturated monomers having two or more ethylenically unsaturated groups such as divinyl adipate, diallyl isophthalate, diallyl phthalate, and diallyl maleate;
epoxy group-containing ethylenically unsaturated monomers such as glycidyl (meth)acrylate and 3,4-epoxycyclohexyl (meth)acrylate;
γ-Methacryloxypropyltrimethoxysilane, γ-Methacryloxypropyltriethoxysilane, γ-Methacryloxypropyltributoxysilane, γ-Methacryloxypropylmethyldimethoxysilane, γ-Methacryloxypropylmethyldiethoxysilane, γ-Acryloxy Propyltrimethoxysilane, γ-Acryloxypropyltriethoxysilane, γ-Acryloxypropylmethyldimethoxysilane, γ-Methacryloxymethyltrimethoxysilane, γ-Acryloxymethyltrimethoxysilane, Vinyltrimethoxysilane, Vinyltriethoxysilane , alkoxysilyl group-containing ethylenically unsaturated monomers such as vinyltributoxysilane and vinylmethyldimethoxysilane; but not limited thereto. Among these, use of a hydroxyl group-containing ethylenically unsaturated monomer can further improve the stability of the core-shell emulsion. These may be used individually by 1 type, and may use 2 or more types together.

The acrylic resin emulsion (C) used in the present invention contains 10% by mass to 70% by mass of an ethylenically unsaturated aromatic monomer in 100% by mass of an ethylenically unsaturated monomer, and an alkyl having 1 to 8 carbon atoms. It is preferable to copolymerize (emulsion polymerize) ethylenically unsaturated monomers containing 10% by mass to 90% by mass of group-containing ethylenically unsaturated monomers. By using the ethylenically unsaturated monomer within these ranges, the adhesion between the pretreatment liquid layer (I) and the ink layer (II) can be further improved.

The acrylic resin emulsion (C) used in the present invention can be synthesized using water-soluble polymerization initiators such as persulfates, peroxides and azo compounds. Specifically, for example, ammonium persulfate (APS), potassium persulfate (KPS), hydrogen peroxide, 2,2'-azobis(2-methylpropionamidine) dihydrochloride and the like are preferred. It is preferable to use 0.1 to 10 parts by mass of the water-soluble polymerization initiator with respect to 100 parts by mass of the ethylenically unsaturated monomer.

Moreover, by using a water-soluble polymerization initiator in combination with a reducing agent, the polymerization rate can be increased, or the polymerization can be performed at a low reaction temperature. The reducing agent includes reducing inorganic compounds such as scorbic acid, ersorbic acid, tartaric acid, citric acid, glucose, sodium sulfite, sodium bisulfite, and sodium metabisulfite. The reducing agent is an ethylenically unsaturated monomer. It is preferable to use 0.05 to 5 parts by mass with respect to 100 parts by mass of the body.

In the present invention, a neutralized water-soluble polymer compound can be used in synthesizing the emulsion. The water-soluble polymer compound can be water-soluble by the neutralization. A basic compound can be used for the neutralization.
Specifically, for example, amines such as ammonia, trimethylamine, triethylamine, butylamine, 2-dimethylaminoethanol, 2-diethylaminoethanol, diethanolamine, triethanolamine, aminomethylpropanol, morpholine;
hydroxide salts such as potassium hydroxide and sodium hydroxide; Among these, ammonia is preferable because it can be easily removed by drying after coating.

A buffering agent and a chain transfer agent can be appropriately used when synthesizing the acrylic resin emulsion (C) used in the present invention. Examples of the buffering agent include sodium acetate, sodium citrate, sodium bicarbonate and the like. Examples of the chain transfer agent include mercaptans such as octyl mercaptan, 2-ethylhexyl thioglycolate, octyl thioglycolate, stearyl mercaptan, lauryl mercaptan and t-dodecyl mercaptan.

A surfactant can be used in synthesizing the acrylic resin emulsion (C) used in the present invention. Examples of the surfactant include higher fatty acid salts such as sodium oleate, alkylarylsulfonates such as sodium dodecylbenzenesulfonate, alkylsulfuric acid ester salts such as sodium lauryl sulfate, and poly(ethylene Oxyethylene alkyl ether sulfates, polyoxyethylene alkyl aryl ether sulfates such as sodium polyoxyethylene nonylphenyl ether sulfate, alkyl sulfosuccinates such as sodium monooctyl sulfosuccinate, sodium dioctyl sulfosuccinate and sodium polyoxyethylene lauryl sulfosuccinate anionic non-reactive emulsifiers such as acid ester salts and derivatives thereof, polyoxyethylene distyrenated phenyl ether sulfate ester salts;
Polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether and polyoxyethylene stearyl ether, polyoxyethylene alkylphenyl ethers such as polyoxyethylene octylphenyl ether and polyoxyethylene nonylphenyl ether, sorbitan monolaurate, sorbitan mono Stearate, sorbitan higher fatty acid esters such as sorbitan trioleate, polyoxyethylene sorbitan higher fatty acid esters such as polyoxyethylene sorbitan monolaurate, polyoxyethylene such as polyoxyethylene monolaurate and polyoxyethylene monostearate Nonionic non-reactive emulsifiers such as higher fatty acid esters, glycerin higher fatty acid esters such as oleic acid monoglyceride and stearic acid monoglyceride, polyoxyethylene/polyoxypropylene block copolymers, polyoxyethylene distyrenated phenyl ether;
anionic reactive emulsifiers such as polyoxyethylene-1-(allyloxymethyl)alkyl ether sulfate;
nonionic nonionic reactive emulsifiers such as polyoxyethylene-1-(allyloxymethyl)alkyl ether;

The acid value of the acrylic resin emulsion (C) used in the present invention is 5 mgKOH/g or more and 65 mgKOH/g or less, more preferably 10 mgKOH/g or more and 60 mgKOH/g or less. By setting the acid value of the acrylic resin emulsion (C) within the above range, the coagulant contained in the pretreatment liquid layer (I) is more trapped and water is prevented from permeating into the pretreatment layer (I). can be done. On the other hand, when the acid value is less than 5 mgKOH/g, the trapping function of the coagulant is small and the water resistance of the coating film is lowered. Furthermore, the dispersion stability of the acrylic resin emulsion itself is low, and aggregates may be generated. On the other hand, if the acid value exceeds 65 mgKOH/g, the rate of aggregation and thickening by the aggregating agent is too fast, so that the leveling property of the overcoat liquid (III) is lowered and coating unevenness occurs. Furthermore, the water resistance of the coating film obtained will also fall. The acid value of the acrylic resin emulsion (C) may be either the emulsion or the water-soluble polymer contained in the acrylic resin emulsion (C).

The glass transition temperature (Tg) of the acrylic resin emulsion (C) used in the present invention is preferably 20°C or higher and 60°C or lower, more preferably 30°C or higher and 55°C or lower. By setting the glass transition temperature of the acrylic resin emulsion (C) within the above range, the adhesion between the pretreatment liquid layer (I) and the ink layer (II) can be further improved.

The acrylic resin emulsion (C) used in the present invention preferably has a weight average molecular weight of 200,000 to 1,000,000, more preferably 300,000 to 500,000. When the weight average molecular weight is in the range of 200,000 to 1,000,000, the adhesion between the pretreatment liquid layer (I) and the ink layer (II) can be further improved.

When the acrylic resin emulsion (C) contained in the overcoat liquid (III) used in the present invention is a core-shell emulsion, the core portion is 150 to 400 parts by mass with respect to the shell portion of 100 parts by mass. preferable. By setting the core-shell ratio of the core-shell emulsion within the above range, emulsion polymerization is facilitated and a uniform emulsion can be obtained. It can improve adhesion.

The content of the acrylic resin emulsion (C) used in the present invention is in the range of 5% by mass or more and 40% by mass or less, more preferably 10% by mass or more and 35% by mass or less, relative to the total amount of the overcoat liquid (III). and particularly preferably in the range of 15% by mass or more and 30% by mass or less. By setting the content of the acrylic resin emulsion (C) within the above range, the adhesion between the pretreatment liquid layer (I) and the ink layer (II) can be further improved.

Further, when the acrylic resin emulsion (C) is a core-shell emulsion, commercial products such as JONCRYL67, JONCRYL678, JONCRYL586, JONCRYL611, JONCRYL683, JONCRYL690, JONCRYL57J, JONCRYL60J, JONCRYL61J, and JONCRYL62 manufactured by BASF Corporation are used as shells. J, JONCRYL63J, JONCRYLHPD -96J, JONCRYL501J, JONCRYLPDX-6102B, BYK-Chemie DISPERBYK, DISPERBYK180, DISPERBYK187, DISPERBYK190, DISPERBYK191, DISPERBYK194, DISPERBYK2010, DISPERBYK2015, DISPERBYK209 0, DISPERBYK2091, DISPERBYK2095, DISPERBYK2155, Zeneca SOLSPERS41000, Sartomer SMA1000H, SMA1440H, SMA2000H , SMA3000H, SMA17352H, and the like.

<Wax particles (D)>
In the wax particles (D) used in the overcoat liquid (III) used in the present invention, some of the particles protrude from the surface of the overcoat liquid (III) layer, and some of the wax particles ( D) melts and spreads over the surface of the overcoat liquid (III) layer. The spread wax imparts high water repellency and slip properties to the surface of the coating film, and the coating film can obtain excellent water rubbing resistance.
The wax particles (D) used in the present invention are used in a form in which a surfactant or a water-soluble polymer compound is adsorbed on the particle surfaces of carnauba wax or montan wax and dispersed in an aqueous medium. Examples of the aqueous medium include various hydrophilic solvents such as alcohols, glycols, glycol ethers, and acetates, and water. These may be used alone or may be used in combination. . The dispersion may be hereinafter referred to as "aqueous wax dispersion".

<Carnauba wax>
Carnauba wax is obtained in the form of powder dusted on the surface of Brazilian wax palm leaves, and contains ceryl hydroxycerotate as the main component. They are classified by type according to the part of the leaves. From the soft leaves at the tip of the tree, they are produced by type 1: light yellow, towards the bottom of the tree, type 2: light yellow to light brown, and type 3: brown. be. Carnauba wax No. 1 is preferred as the carnauba wax used in the wax particles (D) used in the present invention.

<Montan Wax>
Montan wax is obtained by using crude montan wax obtained by solvent extraction from lignite as a base raw material, and is obtained as a main component of straight-chain carboxylic acid having 28 carbon atoms. Acid wax is produced by oxidizing crude montan wax, ester wax is further esterified with a higher alcohol, and partially saponified ester wax is produced by saponifying with a metal oxide after partial esterification. Ester wax is preferable as the montan wax used in the wax particles (D) used in the present invention.

A water-soluble polymer compound can be used for dispersing the wax particles (D) used in the present invention in water. The water-soluble polymer compound is preferably a resin having an acid value of 100 to 500 mgKOH/g and a number average molecular weight of 2,000 to 50,000.

The water-soluble polymer compound functions as a polymer emulsifier by neutralizing the carboxyl groups and the like in the compound with a basic compound described later. When the acid value of the resin is less than 100 mgKOH/g, the emulsification function after neutralization is small, making it difficult to stably disperse the wax, which may result in the formation of wax aggregates in the aqueous wax dispersion. On the other hand, if the acid value exceeds 500 mgKOH/g, the water resistance of the coating film obtained from the ink set of the present invention containing the wax particles (D) may deteriorate. Further, when the weight average molecular weight is 2,000 to 50,000, the wax can be dispersed more easily. A more preferred weight average molecular weight is in the range of 2,000 to 20,000. The polymer compound is preferably an acrylic resin having a carboxyl group.

The aqueous wax dispersion preferably contains 1 to 50 parts by weight of the water-soluble polymer compound and 50 to 99 parts by weight of the wax in a total of 100 parts by weight of the water-soluble polymer compound and the wax. When the water-soluble polymer compound and the wax are used in the amounts described above, it becomes easier to achieve both dispersion stability and coating film performance. It is more preferable that the amount of resin is 2 to 10 parts by weight.

Of the water-soluble polymer compounds used in the aqueous wax dispersion, the acrylic resin having a carboxyl group is obtained by synthesizing in the same manner as the shell portion of the acrylic resin emulsion (C) described above.

A surfactant can be used for dispersing the wax particles (D) used in the present invention in water. Examples of the surfactant include higher fatty acid salts such as sodium oleate, alkylarylsulfonates such as sodium dodecylbenzenesulfonate, alkylsulfuric acid ester salts such as sodium lauryl sulfate, and poly(ethylene Oxyethylene alkyl ether sulfates, polyoxyethylene alkyl aryl ether sulfates such as sodium polyoxyethylene nonylphenyl ether sulfate, alkyl sulfosuccinates such as sodium monooctyl sulfosuccinate, sodium dioctyl sulfosuccinate and sodium polyoxyethylene lauryl sulfosuccinate Anionic emulsifiers such as acid ester salts and derivatives thereof, polyoxyethylene distyrenated phenyl ether sulfate ester salts;
Polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene alkylphenyl ethers such as polyoxyethylene octylphenyl ether, sorbitan higher fatty acid esters such as sorbitan monolaurate, polyoxyethylene sorbitan monolaurate, etc. polyoxyethylene sorbitan higher fatty acid esters, polyoxyethylene higher fatty acid esters such as polyoxyethylene monolaurate, glycerin higher fatty acid esters such as oleic acid monoglyceride, nonionic emulsifiers such as polyoxyethylene distyrenated phenyl ether ; and the like. These may be used alone, or may be used in combination of multiple types, but are not limited to these.

The wax particles (D) used in the present invention preferably have a melting point of 80° C. or higher and 90° C. or lower. By setting the melting point of the wax particles (D) within the above range, a part of the wax particles (D) protruding from the surface of the coating layer melts in the hot air drying temperature range in printing of flexible packaging materials to form an overcoat. It spreads on the liquid (III) layer surface. The spread wax can impart high water repellency and slip properties to the surface of the coating film, resulting in prints having excellent water abrasion resistance. On the other hand, when the wax particles (D) have a melting point of less than 80° C., the wax itself lacks abrasion resistance. On the other hand, if the melting point of the wax particles (D) exceeds 90° C., the wax particles (D) melt less during drying, failing to bring higher slip properties and water repellency to the surface of the coating film, and exhibit no effect on water abrasion resistance.

The wax particles (D) used in the present invention preferably have an average particle diameter (D50) of 50 nm or more and 200 nm or less. By setting the average particle diameter of the wax particles (D) within the above range, higher slip properties and gloss can be imparted to the surface of the overcoat liquid (III) layer.

The wax particles (D) used in the present invention preferably have a penetration of 5 or less, more preferably 3 or less. By setting the penetration of the wax particles (D) within the above range, higher abrasion resistance can be imparted to the surface of the overcoat liquid (III) layer.

Moreover, the overcoat liquid (III) can be used in combination with a fine resin particle dispersion containing a carbodiimide group. The binder resin, the pigment dispersion resin (B), and the acrylic emulsion (C) contain structures derived from ethylenically unsaturated monomers containing anionic groups, and react with the carbodiimide groups of the carbodiimide group-containing resin fine particle dispersion. , water resistance and alcohol resistance are improved.

As the carbodiimide group-containing resin fine particle dispersion, a water dispersion obtained by modifying a hydrophilic group to polycarbodiimide produced from dicyclohexylmethane-4,4'-diisocyanate or 1,3-bis(2-isocyanato-2-propyl)benzene. A body etc. are mentioned. Examples of commercially available products include Carbodilite E-02, E-03A, SV-02, V-02, V-02-L2, V-04 manufactured by Nisshinbo.

The amount of the carbodiimide group-containing fine resin particle dispersion to be added is preferably about 0.5 to 10% by mass based on the total amount of the overcoat liquid (III). If the amount added is less than 0.5% by mass, the above effect may not be confirmed. On the other hand, if it exceeds 10% by mass, the storage stability may deteriorate.

In addition, the overcoat liquid (III) may contain a hydrazide-based additive for the purpose of improving the adhesion to the substrate, or for room-temperature cross-linking of the resin (in the case of containing a keto group). Examples of hydrazide additives include adipic acid dihydrazide.

<Other ingredients>
In addition, a water-soluble organic solvent, a pH adjuster, an antifoaming agent, a thickener, an antiseptic and the like can be appropriately added to the overcoat liquid (III) used in the present invention.

<Manufacture of printed matter>
The printing method for the water-based ink set of the present invention is not particularly limited. It is preferable to include a step of applying by a one-pass printing method and a step of applying the overcoat liquid (III).

In the present invention, the "one-pass printing method" refers to a printing method in which an inkjet head is scanned only once against a stationary substrate, or the substrate is passed through the bottom of a fixed inkjet head only once for printing. be.

The pretreatment liquid (I) and the overcoat liquid (III) are not particularly limited in application, and known coating methods can be used, but flexography and gravure are preferred. The flexographic method is a method in which paint is first transferred from an intaglio called an anilox roll to a resin plate or rubber plate, and the coating agent on the resin plate or rubber plate is transferred to the original roll. It is also possible to pattern a resin plate or a rubber plate. The gravure method includes a method in which a coating agent is directly transferred from an intaglio to an original sheet, and a so-called gravure offset method in which the coating agent is first transferred from the intaglio to a planographic plate and then transferred to the original sheet. It is also possible to pattern an intaglio. In the case of the gravure method, it is preferable to perform a press treatment with a smoothing roll after coating.

<Recording medium>
Any known recording medium can be used when printing with the ink set of the present invention. For example, paper substrates such as coated paper, art paper, and lightly coated paper, thermoplastic materials such as polyvinyl chloride sheets, polyethylene terephthalate (PET) films, polypropylene films, polyethylene films, nylon films, polystyrene films, and polyvinyl alcohol films A resin substrate or a metal substrate such as an aluminum foil can be used. The surface of the base material may be smooth or uneven, and may be transparent, translucent, or opaque. Also, two or more of these recording media may be pasted together. Furthermore, a release adhesive layer or the like may be provided on the opposite side of the printed surface, or an adhesive layer or the like may be provided on the printed surface after printing. The shape of the recording medium may be roll-shaped or sheet-shaped.

Among them, a non-permeable base material or a low-permeability base material is particularly preferable from the viewpoint of laminating and protecting the contents as a packaging material. Since the surface of the hardly permeable base material is subjected to surface treatment such as corona treatment, it is possible to exhibit high adhesion with the pretreatment liquid used in the present invention. Therefore, the strength after lamination is improved, and it becomes possible to protect the contents as a flexible packaging material.
Non-permeable substrates are also particularly preferred. In the case of a non-penetration base material, the pretreatment liquid does not easily penetrate into the base material, so that the interaction with the inkjet ink increases and excellent print quality can be achieved. In this specification, the permeability of a recording medium is determined by the amount of water absorption measured by a dynamic scanning absorptiometer. Specifically, a recording medium having a pure water absorption of less than 1 g/m ² at a contact time of 100 msec, as measured by the following method, is defined as a “impermeable substrate” and is 1 to 10 g/m ² . Let the recording medium be a "hardly permeable base material".

The water absorption amount of the recording medium can be measured, for example, under the following conditions. Using KM500win manufactured by Kumagai Riki Kogyo Co., Ltd. as a dynamic scanning absorptiometer, under the conditions of 23 ° C. and 50% RH, using a recording medium of about 15 to 20 cm square, pure water under the conditions shown below. Measure the amount of transition.
・Measurement method: Spiral Scanning (Spiral Method)
・Measurement start radius: 20 mm
・Measurement end radius: 60 mm
・Contact time: 10 to 1,000msec
・ Number of sampling points: 19 (measured at approximately equal intervals with respect to the square root of the contact time)
・Scan interval: 7 mm
・Rotary table speed switching angle: 86.3 degrees ・Headbox conditions: width 5 mm, slit width 1 mm

In order to sufficiently exhibit the functions of the ink set of the present invention, the impermeable substrate is preferably a thermoplastic resin substrate, and particularly preferably a PET film, polypropylene film, polyethylene film, or nylon film. . It is also preferable to apply a surface modification method such as corona treatment or plasma treatment to the impermeable substrate.

EXAMPLES Hereinafter, the water-based ink set, which is an embodiment of the present invention, will be described more specifically with reference to examples and comparative examples. In the following description, "parts" and "%" represent "parts by mass" and "% by mass", respectively, unless otherwise specified.

(Glass transition temperature/melting point)
The temperature at the inflection point in the baseline shift was defined as the glass transition temperature by differential scanning calorimeter (DSC) measurement, and the melting point was defined as the endothermic peak temperature. DSC8231 manufactured by Rigaku Corporation was used as a measuring device. The measurement temperature range was -100 to 200°C.

(acid number)
It is the number of mg of potassium hydroxide required to neutralize the acidic component contained in 1 g of the resin solid content, and the dried resin is calculated by potentiometric titration with a potassium hydroxide/ethanol solution according to the method described in JISK2501. bottom.

(Weight average molecular weight)
A weight average molecular weight is a polystyrene conversion value by GPC (gel permeation chromatography) measurement. The resin was dissolved in tetrahydrofuran to prepare a 0.1% solution, and the weight average molecular weight was measured by Tosoh HLC-8320-GPC (column: TSKgel-SuperMultiporeHZ-M0021488 molecular weight measurement range of about 2000 to about 2000000).

(Average particle size)
Using Nanotrac UPA150 manufactured by Microtrac Bell Co., it was measured by a particle distribution measurement method based on a dynamic light scattering method, and the value of D50 was defined as an average particle diameter.

(penetration)
It was measured according to the method described in JIS K2235. A weight of 100 g is applied to a specified needle at a standard temperature, and the number of millimeters the needle penetrates into the sample in 5 seconds is determined, and this value is multiplied by 10. A wax sample that was allowed to cool after being melted was measured at 25° C. and calculated.

<Production example of pretreatment liquid (I)>
The following materials were placed in a mixing container equipped with a stirrer, mixed at room temperature (25° C.) for 1 hour, and then filtered through a membrane filter with a pore size of 1 μm to obtain pretreatment liquid (I).
Superchron E480T (solid content 30%) 16.7 parts Calcium acetate 5.0 parts Surfynol 465 1.0 parts Proxel GXL 0.1 parts 2-propanol 5.0 parts Deionized water 72.3 parts Details of the above materials is as follows.
・ Calcium acetate: manufactured by Kishida Chemical Co., Ltd. ・ Superchron E480T: water-based chlorinated polyolefin manufactured by Nippon Paper Industries ・ Surfynol 465: acetylene diol-based surfactant manufactured by Air Products ・ Proxel GXL: manufactured by Arch Chemicals

<Production of water-based inkjet ink>
<Synthesis Example of Pigment Dispersion Resin (B)>
A reaction vessel equipped with a gas inlet tube, a thermometer, a condenser and a stirrer was charged with 95 parts of butanol and purged with nitrogen gas. The inside of the reaction vessel was heated to 110° C., and 35 parts of styrene, 35 parts of acrylic acid, 30 parts of behenyl acrylate as polymerizable monomers, and V-601 (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) as a polymerization initiator were added. A mixture of 6 parts was added dropwise over 2 hours to carry out a polymerization reaction. After completion of the dropwise addition, the mixture was further reacted at 110° C. for 3 hours, then 0.6 part of V-601 was added, and the reaction was further continued at 110° C. for 1 hour to obtain a pigment dispersion resin solution. Furthermore, after cooling to room temperature, dimethylaminoethanol was added to completely neutralize the mixture, and then 100 parts of water was added to make it aqueous. Thereafter, the mixture was heated to 100° C. or higher to azeotrope butanol with water to distill off the butanol, and the solid concentration was adjusted to 30%. Thus, an aqueous solution of the pigment dispersion resin having a solid content concentration of 30% was obtained. The pigment dispersion resin had a weight average molecular weight of 28,000 and an acid value of 273 mgKOH/g.

<Production example of pigment dispersion (C, M, Y, K)>
20 parts of Lionol Blue 7358G (CI Pigment Blue 15:4) manufactured by Toyo Color Co., Ltd., 15 parts of an aqueous solution of Pigment Dispersion Resin 1 (solid concentration: 30%), and 65 parts of water were mixed and mixed with a disper. After pre-dispersion, main dispersion was performed using a Dyno mill with a volume of 0.6 L filled with 1800 g of zirconia beads with a diameter of 0.5 mm to obtain a pigment dispersion liquid C (cyan). In addition, the above C. I. Pigment dispersions M (magenta), Y (yellow), and K (black) were obtained in the same manner as Pigment dispersion C, except that Pigment Blue 15:3 was replaced with the following pigments.
・Magenta: FASTGEN SUPER Magenta RGT manufactured by DIC
(CI Pigment Red 122)
・Yellow: LIONOL YELLOW TT-1405G manufactured by Toyo Color Co., Ltd.
(CI Pigment Yellow 14)
・Black: Printex85 manufactured by Orion Engineered Carbons
(C.I.Pigment Black 7)

<Production Example of Pigment Dispersion W>
40 parts of CR-90-2 (titanium oxide) manufactured by Ishihara Sangyo Co., Ltd., 30 parts of aqueous solution of pigment dispersion resin (solid content concentration 30%), 30 parts of water are mixed, and the same method as pigment dispersion C to obtain a pigment dispersion liquid W.

<Synthesis Example of Binder Resin 1>
A reaction vessel equipped with a gas inlet tube, a thermometer, a condenser and a stirrer was charged with 93.4 parts of butanol and purged with nitrogen gas. The inside of the reaction vessel is heated to 110 ° C., 30 parts of styrene as polymerizable monomers, 5 parts of methacrylic acid, 50 parts of methyl methacrylate, 15 parts of lauryl methacrylate and V-601 (Fujifilm Wako Pure Chemical Industries, Ltd.) as a polymerization initiator 6 parts of the mixture was added dropwise over 2 hours to carry out a polymerization reaction. After completion of the dropwise addition, the mixture was further reacted at 110° C. for 3 hours, then 0.6 part of V-601 was added, and the reaction was further continued at 110° C. for 1 hour to obtain a dispersion resin solution. Further, after cooling to room temperature, 37.1 parts of dimethylaminoethanol was added for neutralization, and 100 parts of water was added to make it aqueous. After that, the mixture was heated to 100° C. or higher to azeotrope butanol with water to distill off the butanol, and the solid content was adjusted to 30%. Thus, an aqueous solution of binder resin 1 having a solid content of 30% was obtained. The weight average molecular weight of binder resin 1 was 18,000. The acid value of binder resin 1 was 32 mg/KOH.

<Production example of inkjet ink>
The materials described below for inkjet ink C were sequentially charged into a mixing container while being stirred by a disper, and were stirred until they were sufficiently uniform. After that, filtration was performed with a membrane filter having a pore size of 1 μm to obtain Ink C. Ink M, ink Y, and ink K were obtained by using pigment dispersions M, Y, and K instead of pigment dispersion C, respectively. Ink W was also obtained from the materials described in Ink Jet Ink W below. Each inkjet ink consisting of five colors in total was obtained.
(Inkjet ink C)
Pigment dispersion liquid C 25.0 parts Binder resin 1 (solid content concentration 30%) 25.0 parts 1,2-propanediol 20.0 parts Surfynol 465 1.0 parts BYK-349 1.0 parts Proxel GXL 0.0 parts 05 parts deionized water 27.95 parts

(inkjet ink W)
Pigment dispersion W 40.0 parts Binder resin 1 (solid content concentration 30%) 25.0 parts 1,2-propanediol 20.0 parts Surfynol 465 1.0 parts BYK-349 1.0 parts Proxel GXL 0.0 parts 05 parts ion-exchanged water 12.95 parts The details of the above materials are as follows.
・ BYK-349: A siloxane-based surfactant manufactured by BYK-Chemie Japan Co., Ltd.

<Production example of overcoat liquid (III)>
<Synthesis Example of Binder Resin 2>
A reactor equipped with a stirrer, a thermometer, two dropping funnels and a reflux device was charged with 60.7 parts of isopropyl alcohol, and the temperature was raised to 80° C. under nitrogen reflux while stirring. Next, two dropping funnels were prepared, one containing 30.0 parts of styrene (St), 39.0 parts of methyl methacrylate (MMA), 7.0 parts of butyl acrylate (BA), and 24 parts of acrylic acid (AA). 0.0 part was prepared and added dropwise over 3 hours. To the other, 10.0 parts of azobisisobutyronitrile (AIBN) dissolved in 6.0 parts of isopropyl alcohol was charged and added dropwise over 4 hours. After the dropping was completed, the reaction was continued at the reflux temperature for 10 hours, and then terminated. Further, after cooling to room temperature, 25% aqueous ammonia was added to completely neutralize the mixture, and then 150 parts of water was added to make it aqueous. Thereafter, the mixture was heated to 100° C., isopropyl alcohol was azeotropically distilled with water, and the isopropyl alcohol was distilled off to adjust the solid content concentration to 30%. As a result, binder resin 2, which is a water-soluble polymer compound having a solid concentration of 30%, was obtained. Binder Resin 2 had a weight average molecular weight of 9000, an acid value of 187 mgKOH/g, and a glass transition temperature of 86°C.

<Synthesis example of binder resins 3 to 4>
Binder resins 3 and 4 were obtained by reacting in the same manner as binder resin 2 except that the raw materials and compounding ratios shown in Table 1 were changed.

<Synthesis Example of Acrylic Resin Emulsion (C) 1>
142.9 parts of binder resin 2 and 50.0 parts of ion-exchanged water were charged into a reaction vessel equipped with a stirrer, thermometer, two dropping funnels and a reflux vessel, and the temperature was raised to 80°C under nitrogen reflux. Next, two dropping funnels were prepared, and 29.0 parts of styrene (St), 33.0 parts of methyl methacrylate (MMA), and 38.0 parts of butyl acrylate (BA) were charged to one of them and dropped over 2 hours. bottom. To the other, 5.0 parts of an ammonium persulfate aqueous solution (APS) having a concentration of 20% was added dropwise over 2 hours. After completion of dropping, the reaction was continued at 80° C. for 2 hours and then terminated. Next, acrylic resin emulsion (C) 1 was obtained by adjusting the non-volatile content of the solution to 40% with deionized water. The acrylic resin emulsion (C) 1 had a weight average molecular weight of 540,000, an acid value of 56 mgKOH/g, and a glass transition temperature of 39°C.

<Synthesis example of acrylic resin emulsion (C) 2 to 5>
Acrylic resin emulsions (C) 2 to 5 were obtained by reacting in the same manner as acrylic resin emulsion (C) 1 except that the raw materials and compounding ratios shown in Table 2 were changed.

<Synthesis Example of Resin for Wax Dispersion>
A reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping vessel and nitrogen gas introduction tube was charged with 590 parts of n-butanol and heated to 110°C. A mixture of 105 parts of methacrylic acid, 105 parts of styrene, 90 parts of ethyl acrylate, 100 parts of n-butanol and 5 parts of benzoyl peroxide was continuously added dropwise from the dropping tank over 2 hours. After 1 hour and 2 hours from the end of dropping, 0.5 part of benzoyl peroxide was added respectively, and the reaction was continued for 3 hours from the end of dropping. A resin solution was obtained. This solution is used as a wax-dispersing resin solution.

<Production Example of Wax Particle Aqueous Dispersion (D-1)>
100 parts of refined carnauba wax characteristic No. 1 (melting point: 84°C) and 17.5 parts of resin solution for wax dispersion were charged into a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping tank, and nitrogen gas inlet tube. , was heated to 90° C. and mixed and dissolved. Then, 1.7 parts of dimethylaminoethanol was added and stirred, and then 220 parts of water was gradually added while maintaining the temperature in the reaction vessel at 85 to 90° C. for emulsification. After that, the mixture was heated to 100° C. or higher, and butanol was azeotropically distilled with water to distill off the butanol, and the non-volatile content was adjusted to 31.6%. As a result, an aqueous dispersion of wax particles having a wax concentration of 30% and an average particle diameter of 120 nm was obtained. This is designated as Wax Particle Aqueous Dispersion (D-1).

<Production Examples of Wax Particle Aqueous Dispersions (D-2 to 6)>
Aqueous wax particle dispersions (D-2 to D-6) were obtained by dispersing in the same manner as for the aqueous wax particle dispersion (D-1), except that the raw materials and blending ratios were changed as shown in Table 3.

Details of the materials used in Table 3 are as follows.
・Refined carnauba wax special No. 1: carnauba wax manufactured by Nippon Wax, melting point 84°C
・LICOWAX E: Montan wax manufactured by Clariant Chemicals, melting point 83°C
・LICOWAX WE40: Montan wax manufactured by Clariant Chemicals, melting point 74°C
・LICOWAX OP: Montan wax manufactured by Clariant Chemicals, melting point 99°C

<Production Example of Overcoat Liquid (III) 1>
The materials described below were sequentially charged into a mixing vessel while stirring with a disper, and stirred until they were sufficiently uniform. Thereafter, filtration with a filter cloth having a pore size of 50 μm was performed.
Acrylic resin emulsion (C) 1 (solid concentration 40%) 55.0 parts 1,2-propanediol 7.0 parts Surfynol 465 1.0 parts BYK-349 1.0 parts Wax particle aqueous dispersion (D- 1) (Solid content concentration 31.6%) 15.0 parts Proxel GXL 0.05 parts Ion-exchanged water 20.95 parts

<Production Examples of Overcoat Liquids (III) 2 to 12>
Overcoat liquids (III) 2 to 12 were obtained in the same manner as overcoat liquid (III) 1, except that the materials listed in Table 4 were used.

Details of the materials used in Table 4 are as follows.
- BYK AQUACER531: Polyethylene wax aqueous dispersion manufactured by BYK-Chemie Japan, melting point 130°C
・ Carbodilite E03A: Carbodiimide aqueous dispersion manufactured by Nisshinbo Chemical Co., Ltd.

<Example of preparation of printed matter and coated matter for evaluation>
The pretreatment liquid (I), inkjet ink (II), and overcoat liquid (III) thus obtained were used to prepare an ink set, and a printed material and a coated material for evaluation were produced as follows.

Using K Control Coater K202 manufactured by Matsuo Sangyo Co., Ltd. and a wire bar, the adjusted pretreatment liquid (I) was applied to the film substrate so that the coating amount was 6 g / m ² , and was dried in an air oven at 70 ° C. for 3 hours. After drying for 1 minute, a coated product was obtained. An OPP film manufactured by Futamura Corporation (FOR-AQ, thickness 12 μm, impermeable substrate) was used as the film substrate.

Next, an inkjet head KJ4B-1200 (manufactured by Kyocera Corporation, resolution 1200 dpi, maximum drive frequency 64 kHz) is installed on the upper part of the conveyor that can convey the printing substrate, and the inkjet ink (II) prepared above is applied from the upstream side to K (black), C (cyan), M (magenta), Y (yellow), and W (white). Next, after fixing the pretreatment liquid (I) prepared above on the conveyor with the coated surface of the coated article facing upward, the conveyor is driven at 50 m / min, and the installation part of the inkjet head is moved. When passing through, inkjet ink (II) was ejected for printing. The drop volume during printing was adjusted to a desired layer thickness within the range of 1.5 pL to 5 pL. Then, the printed matter was quickly placed in an air oven at 70° C. and dried for 3 minutes to obtain a printed matter.

Next, on the printed surface of the obtained printed matter, using a K control coater K202 manufactured by Matsuo Sangyo Co., Ltd., using a wire bar, the adjusted overcoat solution (III) is coated so that the coating amount is 12 g / m ² . and dried in an air oven at 70° C. for 3 minutes to obtain a coated product for evaluation.

Table 5 shows the combinations of pretreatment liquid (I), inkjet ink (II), and overcoat liquid (III) used to prepare the ink set and each coated article for evaluation.

[Examples 1 to 8, Comparative Examples 1 to 4]
Evaluations 1 to 5 shown below were performed on each coated product for evaluation produced above.

<Evaluation 1: Evaluation of coatability>
Coatability was evaluated by visually observing the degree of uneven coating of the overcoat liquid (III) on the resulting coated product. The evaluation criteria are as follows, and the ⊙ and ◯ evaluations are the practically usable areas. The results are listed in Table 5.
◎: Coating unevenness was not visually observed ○: Slight coating unevenness was visually observed ×: Clear coating unevenness was visually observed

<Evaluation 2: Evaluation of water friction resistance>
Using a Gakushin type rubbing fastness tester, the coated surface was rubbed with a water-containing cotton cloth (Kanakin No. 3) at 500 g/cm ² for 20 times, and the ratio of the peeled area of the coating layer was determined. Evaluation of water friction resistance was performed from. The evaluation criteria are as follows, and the ⊙ and ◯ evaluations are the practically usable areas. The results are listed in Table 5.
◎: No peeling of the coating film ○: Peeling of the coating film is less than 10% △: Peeling of the coating film is 10% or more and less than 50% ×: Peeling of the coating film is 50% or more be

<Evaluation 3: Evaluation of abrasion resistance>
Using a Gakushin type rubbing fastness tester, rub the coated surface with a cotton cloth (Kanakin No. 3) at 500 g/cm ² for 100 times. Evaluation of water friction resistance was performed. The evaluation criteria are as follows, and the ⊙ and ◯ evaluations are the practically usable areas. The results are listed in Table 5.
◎: No peeling of the coating film ○: Peeling of the coating film is less than 10% △: Peeling of the coating film is 10% or more and less than 50% ×: Peeling of the coating film is 50% or more be

<Evaluation 4: Evaluation of alcohol resistance>
A cotton swab dipped in a mixed solvent of water/ethanol (weight ratio: 50/50) was rubbed on the coated surface by 10 reciprocations. The evaluation criteria are as follows, and the ⊙ and ◯ evaluations are the practically usable areas. The results are listed in Table 5.
◎: No erosion on the coating film, no ink adhered to the cotton swab ○: Slight erosion of the coating film, but no ink adhered to the cotton swab △: Erosion of the coating film, no ink adhered to the cotton swab Ink adheres, but the substrate surface is not visible ×: Ink adheres to the cotton swab, and the substrate surface is visible

<Evaluation 5: Gloss>
The 60° gloss of the resulting coated product was measured with a gloss meter (Micro-TRI-gloss manufactured by BYKGardner). The evaluation criteria are as follows, and the ⊙ and ◯ evaluations are the practically usable areas. The results are listed in Table 5.
◎: Gloss 80 or more ○: Gloss 65 or more and less than 80 △: Gloss 50 or more and less than 65 ×: Gloss less than 50

From the above results, the present invention shows that even when printing on non-permeable substrates such as film substrates, the print image quality is good without color mixture bleeding or color unevenness, and the water-soluble adhesive that imparts excellent water abrasion resistance to the printed matter. We were able to provide an ink set and printed matter. Due to the above properties, the present invention is particularly useful for flexible packaging materials.

Claims (7)

An aqueous ink set comprising a pretreatment liquid (I), an inkjet ink (II), and an overcoat liquid (III), wherein the pretreatment liquid (I) contains a flocculant (A), and the inkjet ink (II ) contains a pigment, a pigment dispersion resin (B), a water-soluble organic solvent, a surfactant, and water, and the overcoat liquid (III) contains an acrylic resin emulsion (C), wax particles (D), and water. and the acrylic resin emulsion (C) has an acid value of 5 to 65 mgKOH/g, and the wax particles (D) consist of carnauba wax having a melting point of 80 to 90°C and montan wax having a melting point of 80 to 90°C. An aqueous ink set comprising at least one selected from the group. The water-based ink set according to claim 1, wherein the acrylic resin emulsion (C) has a glass transition temperature of 20 to 60°C. 3. The water-based ink set according to claim 1, wherein the wax particles (D) have an average particle size (D50) of 50 to 200 nm. The aqueous ink set according to any one of claims 1 to 3, wherein the overcoat liquid (III) contains a carbodiimide aqueous dispersion. The water-based ink set according to any one of claims 1 to 4, which is used for flexible packaging materials. A water-based inkjet ink print obtained by printing the water-based ink set according to any one of claims 1 to 5 on a recording medium. A method for producing a water-based inkjet ink printed material using the water-based ink set according to any one of claims 1 to 5, comprising a step of applying pretreatment liquid (I) to a recording medium; ) is applied by a one-pass printing method with the inkjet ink (II), and the step of applying the overcoat liquid (III).