JP7567081B1 - Water-based ink composition, water-based ink, laminate, label, and packaging material - Google Patents

Abstract

The present invention provides a water-based ink composition which can give a coating film having excellent coating film physical properties such as adhesion to substrates, abrasion resistance, water abrasion resistance, heat resistance, and scratch resistance.
[Solution] An aqueous ink composition containing an acrylic emulsion resin (A) having an acid value of less than 40 mgKOH/g, an acrylic emulsion resin (B) having an acid value of 40 mgKOH/g or more and 250 mgKOH/g or less, and either or both of titanium oxide and precipitated barium sulfate.
[Selection diagram] None

Description

The present invention relates to an aqueous ink composition, an aqueous ink, a laminate, a label, and a packaging material.

Packaging materials such as plastic substrates used for packaging food and daily necessities are given design and functionality by, for example, gravure printing or flexographic printing using an ink composition. The coating film, which is the printing layer, is required to have physical properties (coating film properties) such as substrate adhesion, abrasion resistance, heat resistance, and scratch resistance.

Resins to be included in ink compositions have been investigated to improve the physical properties of coating films. Resins included in ink compositions also affect the viscosity stability and pigment dispersibility of the ink composition. In particular, titanium oxide and precipitated barium sulfate, which are used as white pigments, are known to be difficult to disperse in ink compositions because they are heavy and tend to sink. Water-soluble acrylic resins with high acid values are used to improve the dispersibility of titanium oxide and precipitated barium sulfate.

As an aqueous acrylic resin other than water-soluble acrylic resin, acrylic emulsion resin is known. It is known that acrylic emulsion resin can contribute to improving the above-mentioned coating film properties and the physical properties of the ink composition. As an acrylic emulsion resin, core-shell type acrylic emulsion resin having a core part and a shell part is well known, and many acrylic emulsion resins consisting of a core part that is poorly soluble in water and a shell part that has excellent compatibility with water are on the market.

Patent Document 1 discloses an aqueous liquid ink that uses a specific mass ratio of an acrylic emulsion resin with an acid value of 42 mgKOH/g and a water-soluble acrylic resin with an acid value of 220 mgKOH/g. In addition, Patent Document 2 discloses an aqueous ink composition for paper containers that is a mixture of an acrylic emulsion resin and an acrylic resin.

JP 2019-094423 A JP 2016-155965 A

When the inventors of the present application produced a coating film using the ink composition described in Patent Document 1, it was found that the coating film properties, such as abrasion resistance, heat resistance, scratch resistance, etc., were insufficient. In addition, the coating film properties also require substrate adhesion and water abrasion resistance.
The present invention aims to provide an aqueous ink composition that can provide a coating film that is excellent in coating film physical properties such as substrate adhesion, abrasion resistance, water abrasion resistance, heat resistance, and scratch resistance. Another objective of the present invention is to provide an aqueous ink composition that is excellent in viscosity stability and dispersibility of pigments such as titanium oxide and precipitated barium sulfate. Another objective of the present invention is to provide an aqueous ink containing the aqueous ink composition, a laminate having a printed layer formed using the aqueous ink, and a label and a package containing the laminate.

The present invention has the following aspects.
[1] An aqueous ink composition containing an acrylic emulsion resin (A), an acrylic emulsion resin (B), and either or both of titanium oxide and precipitated barium sulfate, wherein the acid value of the acrylic emulsion resin (A) is less than 40 mgKOH/g, the acid value of the acrylic emulsion resin (B) is 40 mgKOH/g or more and 250 mgKOH/g or less, the total content of the solid contents of the acrylic emulsion resin (A) and the acrylic emulsion resin (B) is 15 to 40 mass% relative to the total mass of the solid contents of the aqueous ink composition, and the mass ratio of the solid contents of the acrylic emulsion resin (A) to the solid contents of the acrylic emulsion resin (B) is acrylic emulsion resin (A):acrylic emulsion resin (B)=1:1.0 to 1:40.
[2] The water-based ink composition according to [1], wherein the glass transition temperature of the acrylic emulsion resin (A) is −20 to 60° C., and the glass transition temperature of the acrylic emulsion resin (B) is −20 to 60° C.
[3] The aqueous ink composition according to [1] or [2], which is used together with a curing agent.
[4] The water-based ink composition according to any one of [1] to [3], further comprising resin beads.
[5] The water-based ink composition according to [4], wherein the resin beads have an average particle size of 0.5 to 8 μm.
[6] The water-based ink composition according to any one of [1] to [5], further comprising a silicone-based resin.
[7] The water-based ink composition according to [6], wherein the silicone-based resin is at least one selected from the group consisting of amine-modified silicones, silicone-modified acrylics, and polyether-modified silicones.
[8] An aqueous ink comprising the aqueous ink composition according to any one of [1] to [7].
[9] The water-based ink according to [8], which is for use on a plastic substrate or a paper substrate.
[10] A laminate comprising a substrate and a printed layer formed on at least one surface of the substrate using the aqueous ink according to [8] or [9], the substrate being for use as a plastic substrate or a paper substrate.
[11] A label comprising the laminate according to [10].
[12] A package comprising the laminate according to [10].

According to the present invention, it is possible to provide an aqueous ink composition that can provide a coating film that has excellent coating film physical properties such as substrate adhesion, abrasion resistance, water abrasion resistance, heat resistance, and scratch resistance. It is also possible to provide an aqueous ink composition that has excellent viscosity stability and excellent dispersibility of pigments such as titanium oxide and precipitated barium sulfate. Furthermore, it is also possible to provide an aqueous ink containing the aqueous ink composition, a laminate having a printed layer formed using the aqueous ink, and a label and a package containing the laminate.

FIG. 1 is a cross-sectional view illustrating a schematic example of a laminate of the present invention. FIG. 1 is a cross-sectional view illustrating a schematic example of a laminate of the present invention.

The present invention will be described in detail below. The following embodiments are merely examples for explaining the present invention, and are not intended to limit the present invention to these embodiments. The present invention can be implemented in various forms without departing from the spirit of the present invention.
In the present invention, the term "aqueous" in the aqueous ink composition (aqueous ink) means that the medium contains water.
Acrylic emulsion resin is a type of water-dispersible acrylic resin.
The "solid content" refers to the components contained in the aqueous ink composition (aqueous ink), excluding volatile media such as water and organic solvents, and is the components that will ultimately form the printed layer, and is specifically measured in accordance with JIS K 5601-1-2:2008.
In this specification, "(meth)acrylate" is a general term for "acrylate" and "methacrylate". "(meth)acrylic acid" is a general term for "acrylic acid" and "methacrylic acid". "(meth)acryloyloxy group" is a general term for "acryloyloxy group" and "methacryloyloxy group".
The weight average molecular weight of the acrylic emulsion resin is a weight average molecular weight calculated in terms of the molecular weight of standard polystyrene, and is measured by gel permeation chromatography (GPC).
The glass transition temperature of the acrylic emulsion resin is measured in accordance with JIS K 7121:2012 as follows: Using a differential scanning calorimeter, 10 mg of the acrylic emulsion resin is heated from −100° C. to 160° C. at a temperature rate of 20° C./min to obtain a curve (DSC curve), and the glass transition temperature is determined from the intersection between the baseline and the tangent to the endothermic curve.
The acid value of the acrylic emulsion resin is the amount of potassium hydroxide required to neutralize acid groups such as carboxy groups per gram of sample solid content, expressed in milligrams, and is measured in accordance with JIS K 5601-2-1:1999.

<Water-based ink composition>
The aqueous ink composition according to one embodiment of the present invention contains the following acrylic emulsion resin (A), acrylic emulsion resin (B), and either or both of titanium oxide and precipitated barium sulfate.
The aqueous ink composition may further contain components (optional components) other than the acrylic emulsion resin (A), the acrylic emulsion resin (B), titanium oxide, and precipitated barium sulfate, as necessary, within a range that does not impair the effects of the present invention. For example, the aqueous ink composition typically further contains an aqueous medium.

<Acrylic emulsion resin>
The acrylic emulsion resin is a type of water-dispersible acrylic resin, and is, for example, an emulsion-type resin having a core-shell structure. The core of the acrylic emulsion resin is made of a hydrophobic acrylic resin with a relatively high molecular weight, and the shell is made of a hydrophilic acrylic resin with a relatively low molecular weight. The core and shell may be bonded together by a crosslinking agent.

The acrylic emulsion resin is a resin that contains (meth)acrylate units.
Examples of the acrylic emulsion resin include a homopolymer of (meth)acrylate, a copolymer of two or more kinds of (meth)acrylate, and a copolymer of (meth)acrylate and a monomer other than (meth)acrylate.
The ratio of the (meth)acrylate unit to the total mass of all monomer units constituting the acrylic emulsion resin is preferably 10 to 100 mass%, more preferably 20 to 100 mass%. When the acrylic emulsion resin has an acid value, the ratio of the (meth)acrylate unit to the total mass of all monomer units constituting the acrylic emulsion resin is less than 100 mass%.

Examples of the (meth)acrylate include alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and lauryl (meth)acrylate; cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate; aryl (meth)acrylates such as phenyl (meth)acrylate; aralkyl (meth)acrylates such as benzyl (meth)acrylate; and hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate.
These (meth)acrylates may be used alone or in combination of two or more.

Examples of monomers other than (meth)acrylates include conjugated diene compounds such as 1,3-butadiene, isoprene, and chloroprene; aromatic vinyl compounds such as styrene, α-methylstyrene, halogenated styrene, and divinylbenzene; cyanide vinyl compounds such as acrylonitrile and methacrylonitrile; acrylamides such as N,N-dimethyl(meth)acrylamide and N,N-diethyl(meth)acrylamide; unsaturated carboxylic acids such as (meth)acrylic acid, itaconic acid, maleic acid, and fumaric acid; and unsaturated carboxylic acid esters such as diethyl maleate, dibutyl maleate, dibutyl fumarate, diethyl itaconate, and dibutyl itaconate.
These monomers may be used alone or in combination of two or more.

<Acrylic Emulsion Resin (A)>
The acrylic emulsion resin (A) is an acrylic emulsion resin with a low acid value of less than 40 mgKOH/g. The acid value of the acrylic emulsion resin (A) is preferably 36 mgKOH/g or less, and more preferably 32 mgKOH/g or less from the viewpoints of heat resistance, abrasion resistance, and water abrasion resistance. In one embodiment, the acrylic emulsion resin (A) may not have an acid value (the acid value may be 0 mgKOH/g). The acid value of the acrylic emulsion resin (A) is preferably 5 mgKOH/g or more, more preferably 10 mgKOH/g or more, and even more preferably 20 mgKOH/g or more from the viewpoints of compatibility with the acrylic emulsion resin (B), abrasion resistance, and water abrasion resistance.
When the acid value is less than the upper limit, the pigment dispersibility, the substrate adhesion, the water abrasion resistance, the scratch resistance, and the heat resistance are likely to be improved.When the acid value is equal to or more than the lower limit, the compatibility with the acrylic emulsion resin (B) is likely to be improved.When the acid value of the acrylic emulsion resin (A) is 40 mgKOH/g or more, the scratch resistance, the adhesion, and the water abrasion resistance are poor.

The glass transition temperature (hereinafter also referred to as "Tg") of the acrylic emulsion resin (A) is preferably -20 to 60°C, more preferably -10 to 50°C, and further preferably 10 to 45°C from the viewpoint of abrasion resistance and water abrasion resistance.
When the Tg is equal to or higher than the lower limit, the abrasion resistance and water abrasion resistance are likely to be improved.When the Tg is equal to or lower than the upper limit, the abrasion resistance and water abrasion resistance are likely to be improved.

The weight average molecular weight (hereinafter also referred to as "Mw") of the acrylic emulsion resin (A) is preferably from 20,000 to 1,000,000, more preferably from 50,000 to 1,000,000, and from the viewpoint of adhesion to a substrate, further preferably from 100,000 to 1,000,000.
When the Mw is equal to or greater than the lower limit, the heat resistance is likely to be improved, and when the Mw is equal to or less than the upper limit, the pigment dispersibility is likely to be improved.

<Acrylic Emulsion Resin (B)>
The acrylic emulsion resin (B) is an acrylic emulsion resin having a high acid value of 40 to 250 mgKOH/g. The acid value of the acrylic emulsion resin (B) is preferably 40 to 180 mgKOH/g, more preferably 45 to 150 mgKOH/g, and even more preferably 51 to 85 mgKOH/g from the viewpoint of improving abrasion resistance, water abrasion resistance, and heat resistance.
When the acid value is equal to or greater than the lower limit, the abrasion resistance, water abrasion resistance, heat resistance, scratch resistance, and substrate adhesion are likely to be improved.When the acid value is equal to or less than the upper limit, the substrate adhesion and water abrasion resistance are likely to be improved.
When the acid value of the acrylic emulsion resin (B) is less than 40 mgKOH/g, the adhesion to the substrate is poor, and when it exceeds 250 mgKOH/g, the water abrasion resistance is poor.

The Tg of the acrylic emulsion resin (B) is preferably from -20 to 60°C, and more preferably from -20 to 45°C from the viewpoint of adhesion to the substrate.
When the Tg is equal to or higher than the lower limit, the scratch resistance is likely to be improved, whereas when the Tg is equal to or lower than the upper limit, the adhesion to the substrate is likely to be improved.

The Mw of the acrylic emulsion resin (B) is preferably 50,000 to 300,000, more preferably 50,000 to 500,000, and from the viewpoint of abrasion resistance, is even more preferably 50,000 to 800,000.

The acrylic emulsion resin is obtained by polymerizing a monomer component containing a (meth)acrylate and, if necessary, a monomer other than the (meth)acrylate. When producing an acrylic emulsion resin having an acid value, it is preferable to use an unsaturated carboxylic acid as the monomer other than the (meth)acrylate.
The polymerization method is not particularly limited, and examples thereof include a method of polymerizing a monomer component by a solution polymerization method, a bulk polymerization method, an emulsion polymerization method, etc. in the presence of a known radical polymerization initiator. Among these, the emulsion polymerization method is preferred. Emulsion polymerization is a method of polymerizing a monomer component in an aqueous medium in the presence of an emulsifier. The acrylic emulsion resin may be produced by compounding a core part and a shell part after producing them separately. It may also be produced by multi-stage emulsion polymerization. The acrylic emulsion resin may be a self-crosslinking type.

As the acrylic emulsion resin, a commercially available product may be used.
Commercially available acrylic emulsion resins (A) include, for example, those manufactured by Seiko PMC under the product names "Hilos-X-KE-1148" and "Hilos-X-J-140A" and those manufactured by Covestro Coating Resins under the product names "Neocryl XK-110", "Neocryl A-662", and "Neocryl XK-12". These acrylic emulsion resins (A) may be used alone or in combination of two or more kinds.
Commercially available acrylic emulsion resins (B) include, for example, those manufactured by Seiko PMC under the product names "Hilos-X-ME-2039", "Hilos-X-PE-2109", and "Hilos-X-PE-1126", those manufactured by BASF Japan under the product names "Joncryl PDX-7734", "Joncryl PDX-7158", and "Joncryl PDX-7630A", and those manufactured by Covestro Coating Resins under the product names "Neocryl XK-110", "Neocryl A-662", and "Neocryl XK-12". These acrylic emulsion resins (B) may be used alone or in combination of two or more types.

<Titanium oxide>
Although the titanium oxide is not particularly limited, titanium oxide having a rutile crystal structure is preferable. The titanium oxide is preferably surface-treated with at least one of silica and alumina. That is, it is preferable that the surface has a treatment layer formed by surface-treating with at least one of silica and alumina. By having the treatment layer, printability is improved.
Titanium oxide may be treated with other metals or oxides. Examples of other metals include simple metals such as Si, Al, Zn, and Zr; and oxides of Al, Zn, and the like.
The term "treated" titanium oxide refers to a state in which the surfaces of titanium oxide particles are coated.

The oil absorption of titanium oxide is preferably from 10 to 40 mL/100 g, and more preferably from 15 to 30 mL/100 g.
The oil absorption of titanium oxide is determined in accordance with JIS K 5101-13-1:2004.

The average particle size of titanium oxide is preferably from 0.15 to 0.35 μm, and more preferably from 0.20 to 0.30 μm.
The average particle size of titanium oxide is determined by a method of directly measuring the size of primary particles from images observed under a transmission electron microscope (TEM). Specifically, the particle size of each of 100 randomly selected primary particles is measured, and the average particle size of titanium oxide is calculated by averaging these particle sizes.

Commercially available titanium oxide may be used. Examples of commercially available titanium oxide include those manufactured by Ishihara Sangyo Kaisha under the trade names "CR-50", "CR-50-2", "CR-57", "CR-Super70", "CR-80", "CR-90", "CR-90-2", "CR-93", "CR-95", "CR-953", "CR-97", "UT771", "CR-60", "CR-60-2", "CR-63", "CR-67", "CR-58", "CR-58-2", "CR-85", "R-820", "R-830", "R-930", "R-980", "R-550", "R-630", "R-680", "R-780", "R-780-2", and "R-850". , "A-100", "A-220", "W-10"; trade names "JR-301", "JR-403", "JR-405", "JR-600A", "JR-605", "JR-600E", "JR-603", "JR-805", "JR-806", "JR-701", "JRNC", "JR-800", "JA-1", "JA-C", "JA-3", "JA-4", "JA-5" manufactured by Teika Corporation; trade names "A-190", "R-25", "R-21", "R-32", "R-33", "R-7E", "R-62N", "R-78", "R-42", "R-45M" manufactured by Sakai Chemical Industry Co., Ltd., and the like.
These titanium oxides may be used alone or in combination of two or more.

<Precipitated barium sulfate>
As the precipitated barium sulfate, precipitated barium sulfate known in the art can be used. The average particle size of the precipitated barium sulfate is preferably 0.01 to 1 μm. The average particle size of the precipitated barium sulfate is the cumulative 50% particle size on a volume basis measured by a laser diffraction/light scattering method.

<Optional ingredients>
Examples of the optional components include an aqueous medium, resin beads, a silicone resin, and additives.

(Aqueous medium)
Examples of the aqueous medium include water and mixed solvents of water and an organic solvent.
The organic solvent in the mixed solvent is not particularly limited as long as it is soluble in water, and examples thereof include alcohol-based solvents such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, etc., ketone-based solvents such as acetone, etc., glycol ether-based solvents such as propylene glycol monomethyl ether, etc. These organic solvents may be used alone or in combination of two or more.

The water content relative to the total mass of the aqueous medium is preferably 60 to 100% by mass, more preferably 70 to 100% by mass, and even more preferably 80 to 100% by mass.

(Resin beads)
The resin beads are used to improve the abrasion resistance, water abrasion resistance, and scratch resistance of the resulting coating film.
Examples of the resin type of the resin beads include acrylic resin, styrene resin, silicone resin, and urethane resin, with acrylic resin being preferred.
The average particle size of the resin beads is preferably 0.5 to 8 μm, more preferably 0.5 to 5 μm, and even more preferably 0.5 to 2 μm from the viewpoint of scratch resistance. When the average particle size of the resin beads is within the above range, the plate tone transfer is improved and the ink stability can be improved. The average particle size of the resin beads is the cumulative 50% particle size on a volume basis measured by a laser diffraction/light scattering method.

(Silicone resin)
The silicone resin is used to improve the water abrasion resistance and heat resistance of the resulting coating film.
The silicone resin is a compound having a siloxane bond.

Examples of silicone-based resins include polyether-modified silicones, and other examples include polyorganosiloxanes such as polydimethylsiloxane.
The polyorganosiloxane may be partially modified with an organic group or may not be modified. In addition, it is preferable because it has high solubility and dispersibility in an aqueous medium. The polyorganosiloxane may be reactive or non-reactive, but it is preferable that it is reactive when used in combination with a curing agent described later.
In this specification, polyorganosiloxanes partially modified with organic groups are also referred to as "modified polyorganosiloxanes".

The modified polyorganosiloxane may be, for example, a polyorganosiloxane in which at least one methyl group in polydimethylsiloxane is substituted with a monovalent group other than an alkyl group (hereinafter also referred to as an "organic group"). In this embodiment, at least one terminal methyl group and a side chain methyl group may be substituted with an organic group, at least one terminal methyl group may be substituted with an organic group and the side chain methyl group may not be substituted with an organic group, or at least one side chain methyl group may be substituted with an organic group and the terminal methyl group may not be substituted with an organic group. Among these, it is preferable that at least one side chain methyl group is substituted with an organic group and the terminal methyl group is not substituted with an organic group.

Examples of the organic group include an organic group having an ether group, an organic group having an amino group, an organic group having an epoxy group (including a cyclic epoxy group), an organic group having an ester group, an organic group having an aryl group such as a phenyl group, an organic group having a hydroxyl group, an organic group having a mercapto group, an organic group having a carboxy group, an organic group having a (meth)acryloyloxy group, an organic group having an alkoxy group, and an organic group having an amide group.
The silicone resin may have one type of organic group or two or more types of organic groups.

That is, examples of modified polyorganosiloxanes include polyether-modified polyorganosiloxanes, amino-modified polyorganosiloxanes (amine-modified silicones), epoxy-modified polyorganosiloxanes, polyester-modified polyorganosiloxanes, polyetherester-modified polyorganosiloxanes, aryl-modified polyorganosiloxanes, hydroxyl-modified polyorganosiloxanes, mercapto-modified polyorganosiloxanes, carboxy-modified polyorganosiloxanes, (meth)acryloyloxy-modified polyorganosiloxanes (silicone-modified acrylics), alkoxy-modified polyorganosiloxanes, amide-modified polyorganosiloxanes, etc. Among these, amino-modified polyorganosiloxanes, (meth)acryloyloxy-modified polyorganosiloxanes, and polyether-modified silicones are preferred.
These silicone resins may be used alone or in combination of two or more.

Commercially available silicone-based resins may be used. Commercially available products include, for example, BYK products under the trade names "BYK302", "BYK-307", "BYK313", "BYK322", "BYK323", "BYK325N", "BYK326", "BYK327", "BYK330", "BYK331", "BYK-333", "BYK342", "BYK-345", "BYK-346", "BYK347", "BYK-348", "BYK349", "BYK-375", "BYK377", "BYK378", "BYK3450", "BYK3451", "BYK3455", "BYK3456", "BYK3760", "BYK3550", "BYK SILCLEAN 3700", "BYK SILCLEAN 3701", and "BYK "SILCLEAN 3720"; trade names of Shin-Etsu Chemical Co., Ltd.: "KF-351A", "KF-352A", "KF-353", "KF-354L", "KF-355A", "KF-615A", "KF-945", "KF-640", "KF-642", "KF-643", "KF-6020", "X-22-4515", "KF-868", "KF-865", "KF-8 64'', ``KF-859'', ``KF-393'', ``KF-860'', ``KF-880'', ``KF-8004'', ``KF-8002'', ``KF-8005'', ``KF-867'', ``KF-869'', ``KF-861'', ``X-22-343'', ``KF-101'', ``KF-1'' 001”, “X-22-2000”, “X-22-3820W”, “X-22- 3939A'', ``KP-124'', ``KP-109'', ``KP-110'', ``KP-121'', ``KP-118'', ``KP-341'', ``KP-112'', ``KP-125'', ``KP-101'', ``KP-106'', ``KP-126'', ``KP-360A'''', ``KP-3''. 61", "KP-390", "KP-391", "KP-392", "PAM- E", "KF-8010", "X-22-161A", "X-22-161B", "KF-8012", "KF-8008", "POLON-MF-14", "POLON-MF-14E", "POLON-MF-51", "POLON-MF-14EC", "POLON-MF-63", "KM-9771"; trade names of Dow-Toray Industries, Inc. 501W Additive", "DOWSIL FZ-2104 Fluid", "DOWSIL FZ-2110", "DOWSIL FZ-2123", "DOWSIL FZ-2164", "DOWSIL FZ-2191", "DOWSI L FZ-5609 Fluid", "DOWSIL L-7001", "DOWSIL L-7002", "DOWSIL L-7604", "DOWSIL OFX-0309 Fluid", "DOWSIL OFX-5221 Fluid", "DOWSIL S F-8410 Fluid”, “DOWSIL OFX-0193 Fluid”, “DOWSIL SH-3746 Ｆｌｕｉｄ」、「ＤＯＷＳＩＬ ＳＨ－３７７１ Ｆｌｕｉｄ」、「ＤＯＷＳＩＬ ＳＨ－８４００ Ｆｌｕｉｄ」、「ＤＯＷＳＩＬ ＳＨ－８７００ Ｆｌｕｉｄ」、「ＤＯＷＳＩＬ Ｙ－７００６」、「ＤＯＷＳＩＬ ＦＺ－２２０３」、「ＤＯＷＳＩＬ ＦＺ－２２１５」、「ＤＯＷＳＩＬ ＦＺ－２２２２」、「ＤＯＷＳＩＬ ＢＹ１６－２０５」、「ＤＯＷＳＩＬ ＢＹ１６－２１３」、「ＤＯＷＳＩＬ ＢＹ１６－８４９ Ｆｌｕｉｄ」、「ＤＯＷＳＩＬ ＢＹ１６－８５３Ｕ」、「ＤＯＷＳＩＬ ＢＹ１６－８７１」、「ＤＯＷＳＩＬ ＢＹ１６―８７２」、「ＤＯＷＳＩＬ ＢＹ１６－８７９Ｂ」、「ＤＯＷＳＩＬ BY16-892, DOWSIL FZ-3705, DOWSIL FZ-3710 Fluid, DOWSIL FZ-3785, DOWSIL SF-8417 Fluid; and EVONIK's Tegoglide 482.

The silicone resin may be in the form of a solid, an oil, an emulsion, or a dispersion.
The silicone resin may be copolymerized with an acrylic resin skeleton, in which case compatibility with the acrylic emulsion resin (A) and the acrylic emulsion resin (B) is improved.

(Additives)
Examples of the additives include waxes, thickeners, anti-settling agents, UV absorbers, antioxidants, leveling agents, viscoelasticity modifiers, antifoaming agents, lubricants, dispersants, stabilizers, pH adjusters, and surfactants.
These additives may be used alone or in combination of two or more kinds.
It is preferable that the aqueous ink composition is substantially free of colorants such as pigments other than titanium oxide and precipitated barium sulfate.
Here, the term "substantially free" means that, except for colorants that are unintentionally contained, no colorants are intentionally blended.

Examples of waxes include polyolefin waxes (polyethylene wax, polypropylene wax, etc.), polytetrafluoroethylene wax, Fischer-Tropsch wax, amide wax, microcrystalline wax, montan wax, carnauba wax, paraffin wax, and beeswax. Among these, polyolefin waxes are preferred, and polyethylene wax is more preferred.

Commercially available polyethylene waxes include those manufactured by Mitsui Chemicals under the trade names "CHEMIPERL W100", "CHEMIPERL W200", "CHEMIPERL W300", "CHEMIPERL W308", "CHEMIPERL W400", "CHEMIPERL W401", "CHEMIPERL W500", "CHEMIPERL W640", "CHEMIPERL W700", and "CHEMIPERL W800"; those manufactured by BYK under the trade names "CERAFLOUR 925", "CERAFLOUR 925N", "CERAFLOUR 927N", and "CERAFLOUR 929"; Examples of the wax include "CERAFLOUR 929N", "CERAFLOUR 950", "CERAFLOUR 960", "CERAFLOUR 961", "CERAFLOUR 988", "CERAFLOUR 991", "CERAFLOUR 1000", "AQUACER 531", "AQUACER 537", "AQUACER 552", "AQUACER 840", "AQUACER 1547", and "AQUAMAT 208"; and the product name "JonCrylwax 4" manufactured by BASF Japan.
These waxes may be used alone or in combination of two or more kinds.

The thickener is used to adjust the viscosity of the aqueous ink composition.
Examples of the thickener include urethane-based thickeners, polyacrylic-based thickeners, polyamide-based thickeners, cellulose-based thickeners, clay minerals such as bentonite, etc. Among these, urethane-based thickeners are more preferred.
The urethane thickener is a so-called association type thickener, and effectively exhibits a thickening effect in an aqueous medium by association of urethane bonds with each other. Examples of the urethane thickener (urethane association type thickener) include compounds having urethane bonds and polyether chains in the molecule and having hydrophobic groups at the ends.
Examples of commercially available urethane thickeners include those available under the trade names "SN Thickener 612,""SN Thickener 621N,""SN Thickener 625N,""SN Thickener 627N," and "SN Thickener 660T," manufactured by San Nopco Limited.
These thickeners may be used alone or in combination of two or more kinds.

The defoaming agent is used to defoam the aqueous ink composition.
The antifoaming agent includes a mixture of silicone and hydrophobic particulates.
Commercially available mixtures of silicone and hydrophobic microparticles include those manufactured by BYK Corporation under the trade names "BYK-011", "BYK-012", "BYK-014", "BYK-015", "BYK-017", "BYK-018", "BYK-019", "BYK-021", "BYK-022", "BYK-023", "BYK-024", "BYK-025", "BYK-028", "BYK-038", "BYK-039", "BYK-044", "BYK-093", and BYK-094", "BYK-1610", "BYK-1611", "BYK-1615", "BYK-1617", "BYK-1640", "BYK-1650", "BYK-1710", "BYK-1711", "BYK-1719", "BYK-1723", "B YK-1724”, “BYK-1730”, “BYK-1740”, “BYK-1770”, “BYK-1780”, “BYK-1781”, “BYK-1785”, “BYK-1786” "BYK-1798": trade names of San Nopco Limited: "SN Deformer 121N", "SN Deformer 1311", "SN Deformer 1312", "SN Deformer 1313", "SN Deformer 1314", "SN Deformer 1315", "SN Deformer 1316", "SN Deformer 154", "SN Deformer 154S", "SN Deformer 180", "SN Deformer 265", "SN Deformer 317", "SN Deformer Examples of such deformers include "SN Deformer 380", "SN Deformer 381", "SN Deformer 391", "SN Deformer 393", "SN Deformer 395", "SN Deformer 399", "SN Deformer 5016", "SN Deformer 5016", "Nopco DF-122-NS", "Noptam 3590", "Noptam 6030PC", "Noptam 777-F", "Noptam 8000PC", "Noptam 8034-F", and "Noptam 8034-LF".
These defoaming agents may be used alone or in combination of two or more.

The dispersant is used to enhance the dispersibility of the titanium oxide and precipitated barium sulfate in the aqueous ink composition.
Dispersants include copolymers that have an affinity for titanium oxide and precipitated barium sulfate.
Commercially available dispersants include those manufactured by BYK under the trade names "ANTI-TERRA-250", "DISPERBYK-102", "DISPERBYK-180", "DISPERBYK-184", "DISPERBYK-185", "DISPERBYK-187", "DISPERBYK-190", "DISPERBYK-191", "DISPERBYK-192", and "DISPERBYK-203". BYK-193", "DISPERBYK-194N", "DISPERBYK-199", "DISPERBYK-2010", "DISPERBYK-2012", "DISPERBYK-2013", "DISPERBYK-2015", "DISPERBYK- 2019”, “DISPERBYK-2055”, “DISPERBYK-2060”, “DISPERBYK-2 061", "DISPERBYK-2081", "DISPERBYK-2096", "BYK-154"; trade names manufactured by Lubrizol Corporation include "Solsperse 20000", "Solsperse 40000", "Solsperse 43000", "Solsperse 27000", "Solsperse 40000", "Solsperse 41000", "Solsperse 43000", "Solsperse 44000", "Solsperse 45000", "Solsperse 46000", "Solsperse 47000", "Solsperse 53095", "Solsperse 64000", "Solsperse 65000", "Solsperse 66000", "Solsperse W100", "Solsperse W200", "Solsperse W320", "Solsperse WV400", and "Solsperse J400".
These dispersants may be used alone or in combination of two or more kinds.

Examples of the pH adjuster include aqueous ammonia, sodium hydroxide, potassium hydroxide, and various amines.
These pH adjusters may be used alone or in combination of two or more.

<Content of each ingredient>
The solid content of the acrylic emulsion resin (A) is preferably from 0.36 to 20% by mass, and more preferably from 1.5 to 12% by mass, based on the solid content of the aqueous ink composition, from the viewpoints of abrasion resistance and heat resistance.
When the solid content of the acrylic emulsion resin (A) is within the above range, the abrasion resistance and heat resistance are likely to be improved.

The solid content of the acrylic emulsion resin (B) is preferably 7.5% by mass or more and 39% by mass or less, based on the solid content of the aqueous ink composition, and from the viewpoint of improving abrasion resistance and heat resistance, it is more preferably 15% by mass or more and 23% by mass or less.
When the solid content of the acrylic emulsion resin (B) is within the above range, the abrasion resistance and heat resistance are likely to be improved.

The total content of the solid contents of the acrylic emulsion resin (A) and the acrylic emulsion resin (B) is from 15% by mass to 40% by mass, and preferably from 20% by mass to 40% by mass, and more preferably from 20% by mass to 35% by mass, based on the total mass of the solid contents of the aqueous ink composition. From the viewpoint of excellent abrasion resistance, heat resistance, water abrasion resistance, and scratch resistance, the total content of the solid contents of the aqueous ink composition is more preferably from 20% by mass to 35% by mass.
When the total content of the solid contents of the acrylic emulsion resin (A) and the acrylic emulsion resin (B) relative to the total mass of the solid contents of the aqueous ink composition is equal to or more than the lower limit, the abrasion resistance, water abrasion resistance, scratch resistance, and heat resistance of the resulting coating film are likely to be improved. When the total content of the solid contents of the acrylic emulsion resin (A) and the acrylic emulsion resin (B) is equal to or less than the upper limit, the abrasion resistance and heat resistance of the resulting coating film are likely to be improved.
If the total content of the solid contents of the acrylic emulsion resin (A) and the acrylic emulsion resin (B) is less than 15 mass % relative to the total mass of the solid contents of the aqueous ink composition, the viscosity stability and scratch resistance will be poor, and if it exceeds 40 mass %, the heat resistance will be poor.

The mass ratio of the solid content of the acrylic emulsion resin (A) to the solid content of the acrylic emulsion resin (B), acrylic emulsion resin (A):acrylic emulsion resin (B), is 1:1.0 to 1:40, preferably 1:1.5 to 1:30, and more preferably 1:1.5 to 1:20 from the viewpoint of particularly excellent abrasion resistance and heat resistance.
When the mass ratio is equal to or more than the lower limit, the abrasion resistance is improved.When the mass ratio is equal to or less than the upper limit, the pigment dispersibility, viscosity stability, adhesion to substrate, abrasion resistance, water abrasion resistance, scratch resistance, and heat resistance are likely to be improved.
When the ratio of acrylic emulsion resin (B) in the ratio of acrylic emulsion resin (A):acrylic emulsion resin (B) is less than 1.0, the abrasion resistance is poor, and when it exceeds 40, the viscosity stability is poor.

The total content of titanium oxide and precipitated barium sulfate is preferably 10 to 60 mass %, more preferably 15 to 60 mass %, and even more preferably 20 to 60 mass %, relative to the total mass of the aqueous ink composition, and from the viewpoint of the balance between color development and substrate adhesion, is particularly preferably 25 to 60 mass %.
The total content of titanium oxide and precipitated barium sulfate is preferably 25 to 80 mass %, more preferably 30 to 80 mass %, and even more preferably 40 to 80 mass %, and particularly preferably 50 to 80 mass %, based on the total mass of the solid contents of the aqueous ink composition, from the viewpoint of the balance between color development and substrate adhesion.
When the total content of titanium oxide and precipitated barium sulfate is equal to or more than the lower limit, the coating film tends to have a high uniformity and excellent shielding properties. When the total content of titanium oxide and precipitated barium sulfate is equal to or less than the upper limit, the pigment dispersibility of the aqueous ink composition tends to be improved.

The content of the aqueous medium is preferably 20 to 60% by mass, more preferably 25 to 55% by mass, and even more preferably 30 to 50% by mass, based on the total mass of the aqueous ink composition. When the content of the aqueous medium is equal to or more than the lower limit, the fluidity of the aqueous ink composition is good, and when the content is equal to or less than the upper limit, the drying property of the coating film of the aqueous ink composition is good.
The content of the organic solvent is preferably 0 to 5% by mass, more preferably 0 to 4% by mass, and even more preferably 0 to 3% by mass, based on the total mass of the aqueous ink composition. When the content of the organic solvent is equal to or less than the upper limit, for example, drying does not occur too quickly during flexographic printing, and printing defects such as plate tangling are suppressed.

The content of optional components other than the aqueous medium is not particularly limited as long as it is within a range that does not impair the effects of the present invention. For example, the content is preferably 0 to 10 mass %, and more preferably 0 to 5 mass %, relative to the total mass of the aqueous ink composition.
The content of optional components other than the aqueous medium is preferably 0 to 15 mass %, more preferably 0 to 10 mass %, based on the total mass of the solid contents of the aqueous ink composition.

When the aqueous ink composition contains resin beads as an optional component, the solid content of the resin beads is preferably from 0.05% by mass to 3% by mass, more preferably from 0.05% by mass to 1% by mass, relative to the total mass of the aqueous ink composition, and even more preferably from 0.1% by mass to 0.8% by mass, from the viewpoint of achieving a particularly excellent balance between substrate adhesion and scratch resistance.
When the aqueous ink composition contains resin beads as an optional component, the solid content of the resin beads is preferably from 0.1% by mass to 6% by mass, more preferably from 0.3% by mass to 5% by mass, relative to the total mass of the solid contents of the aqueous ink composition, and even more preferably from 0.5% by mass to 2% by mass, from the viewpoint of achieving a particularly excellent balance between substrate adhesion and scratch resistance.
When the content of the resin beads is within the above range, the abrasion resistance, water abrasion resistance, and scratch resistance of the resulting coating film are likely to be improved.

When the aqueous ink composition contains a silicone-based resin as an optional component, the solid content of the silicone-based resin is preferably from 0.05% by mass to 3% by mass, more preferably from 0.05% by mass to 1% by mass, relative to the total mass of the aqueous ink composition, and even more preferably from 0.1% by mass to 0.8% by mass, from the viewpoint of achieving a particularly excellent balance between water abrasion resistance and heat resistance.
When the aqueous ink composition contains a silicone-based resin as an optional component, the solid content of the silicone-based resin is preferably from 0.1 to 6 mass %, more preferably from 0.3 to 5 mass %, and even more preferably from 0.5 to 2 mass %, relative to the total mass of the solid contents of the aqueous ink composition, from the viewpoint of achieving a particularly excellent balance between water abrasion resistance and heat resistance.
When the content of the silicone resin is within the above range, the water abrasion resistance and heat resistance of the resulting coating film tend to be improved.

When the aqueous ink composition contains a wax as an optional component, the solid content of the wax is preferably 0.1 to 10 mass %, more preferably 0.2 to 5 mass %, and even more preferably 0.3 to 2 mass %, relative to the total mass of the aqueous ink composition.
When the aqueous ink composition contains a wax as an optional component, the content of the solid matter of the wax is preferably 0.2 to 20 mass %, more preferably 0.5 to 15 mass %, and even more preferably 1 to 10 mass %, based on the total mass of the solid matters of the aqueous ink composition.

When the aqueous ink composition contains a thickener as an optional component, the solid content of the thickener is preferably 0.01 to 4 mass%, more preferably 0.03 to 2 mass%, and even more preferably 0.08 to 1 mass%, relative to the total mass of the aqueous ink composition.
When the aqueous ink composition contains a thickener as an optional component, the solid content of the thickener is preferably 0.02 to 7 mass%, more preferably 0.05 to 4 mass%, and even more preferably 0.1 to 2 mass%, relative to the total mass of the solid contents of the aqueous ink composition.
When the solids content of the thickener is equal to or more than the above lower limit, the effect of the thickener is fully exerted and the viscosity of the aqueous ink composition can be easily adjusted to a desired value. When the solids content is equal to or less than the above upper limit, the physical properties of the aqueous ink composition can be well maintained.

When the aqueous ink composition contains a defoaming agent as an optional component, the content of the solid content of the defoaming agent is preferably 0.005 to 2 mass%, more preferably 0.01 to 1 mass%, and even more preferably 0.05 to 0.8 mass%, relative to the total mass of the aqueous ink composition.
When the aqueous ink composition contains a defoaming agent as an optional component, the content of the solid content of the defoaming agent is preferably 0.005 to 4 mass%, more preferably 0.01 to 2 mass%, and even more preferably 0.05 to 1 mass%, relative to the total mass of the solid content of the aqueous ink composition.

<Method of producing water-based ink composition>
The aqueous ink composition of the present embodiment can be obtained, for example, by mixing an acrylic emulsion resin (A), an acrylic emulsion resin (B), either one or both of titanium oxide and precipitated barium sulfate, and, if necessary, one or more of optional components, so that each component has a desired content. The method of mixing each component is not particularly limited, and each component can be mixed by various methods.
In one embodiment, it is preferable to prepare a millbase composition in advance by mixing the acrylic emulsion resin (A), either or both of titanium oxide and precipitated barium sulfate, and an aqueous medium, and then add the acrylic emulsion resin (B) to produce the aqueous ink composition.

<Applications of the Water-Based Ink Composition>
The aqueous ink composition of the present embodiment is suitable as a white ink composition for printing on the surface of a substrate such as a plastic substrate or a paper substrate, or on the surface of a color ink layer formed on the surface of a substrate, by gravure printing or flexographic printing. In particular, it is suitable as a white ink composition for printing on the surface of a substrate, or on the surface of a color ink layer formed on the surface of a substrate, by flexographic printing. That is, the aqueous ink composition of the present embodiment is suitable for flexographic printing.
The water-based ink composition of this embodiment is preferably used together with a curing agent described below.

<Water-based ink>
The aqueous ink composition comprises the aqueous ink composition of the present invention and may contain other optional components. The aqueous ink can be obtained by combining the composition with optional additives and adjusting the color.

<Mechanism of action>
The aqueous ink composition of the present invention contains two kinds of acrylic emulsion resins with different acid values, with the acid value of 40 mgKOH/g being the boundary. As shown in the examples below, an aqueous ink composition containing only one of the acrylic emulsion resins does not provide the desired physical properties of the aqueous ink composition and the coating film properties. On the other hand, the aqueous ink composition of the present invention has both improved physical properties of the aqueous ink composition and the coating film properties due to the synergistic effect of combining two kinds of acrylic emulsion resins with different acid values, with the acid value of 40 mgKOH/g being the boundary. Furthermore, in the present invention, the effect of improving the physical properties of the aqueous ink composition and the coating film properties is further promoted by adjusting the total content and mass ratio of the two kinds of acrylic emulsion resins with different acid values, with the acid value of 40 mgKOH/g being the boundary. For example, when only one type of acrylic emulsion resin with an acid value of less than 40 mgKOH/g or one type of acrylic emulsion resin with an acid value of 40 mgKOH/g or more is used, the adhesion to the substrate is particularly poor, which is an undesirable embodiment.

<Curing Agent>
The aqueous ink composition of the present embodiment may be used together with a curing agent. For example, the aqueous ink composition and the curing agent may be mixed to prepare a coating liquid, and the obtained coating liquid may be applied to a substrate.
Use of a curing agent improves the coating film properties such as water resistance and abrasion resistance of the coating layer, as well as adhesion to the substrate.

As the curing agent, those known in the art can be used, and examples thereof include isocyanate-based curing agents, blocked isocyanate-based curing agents, carbodiimide-based curing agents, oxazoline-based curing agents, epoxy-based curing agents, aziridine-based curing agents, etc. Among these, from the viewpoint of further improving the scratch resistance of the coating layer, isocyanate-based curing agents, epoxy-based curing agents, and aziridine-based curing agents are preferred.
These curing agents may be used alone or in combination of two or more.

Specific examples of isocyanate-based curing agents include polyisocyanate compounds such as aliphatic, alicyclic, and aromatic. Specific examples of polyisocyanate compounds include aliphatic diisocyanates such as trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, and 2,6-diisocyanate methyl caproate; hydrogenated diisocyanates; Diphenylmethane diisocyanate, isophorone diisocyanate, norbornene diisocyanate, 1,3-cyclopentane diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate), 4,4'-methylenebis(cyclohexyl isocyanate), methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexyl Alicyclic diisocyanates such as 1,4-bis(isocyanatemethyl)cyclohexane and 1,3-bis(isocyanatemethyl)cyclohexane; m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4- or 2,6-tolylene diisocyanate, 4,4'-toluidine diisocyanate, dianisidine diisocyanate, 4 , 4'-diphenyl ether diisocyanate and other aromatic diisocyanates; polyisocyanate compounds obtained by polymerizing the above diisocyanates and having an allophanate structure, a nurate structure, a biuret structure, and the like; triisocyanates such as 1,3,5-triisocyanate benzene, 2,4,6-triisocyanate toluene, and 1,3,5-triisocyanate hexane; and polyisocyanates such as 4,4'-diphenyl dimethyl methane-2,2'-5,5'-tetraisocyanate.

Commercially available isocyanate-based curing agents include those manufactured by Mitsui Chemicals under the product names "Takenate WD-720", "Takenate WD-725", "Takenate WD-726", "Takenate WD-730", "Takenate WD-220", "Takenate XWD-HS7", and "Takenate XWD-HS30"; and those manufactured by Nippon Polyurethane Industry Co., Ltd. under the product names "Aquanate 100", "Aquanate 110", and "Aquanate 120". Asahi Kasei Corporation's product names: "Duranate WB40-100", "Duranate WB40-80D", "Duranate WT20-100", "Duranate WT30-100", "Duranate WL70-100", "Duranate WR80-70P", "Duranate WE50-100"; Bayer MaterialScience's product names: "Bayhydur 3100", "Bayhydur 302", "Bayhydur 304", "Bayhydur 305", "Bayhydur XP2451/1", "Bayhydur XP2487/1", "Bayhydur XP2547", "Bayhydur XP2655", "Bayhydur XP2700"; and BASF product names "Basonat HW100", "Basonat HA100", and "Basonat HW1180PC".
The isocyanate-based curing agent may be used alone or in combination of two or more kinds.

Specific examples of blocked isocyanate curing agents include those blocked with a blocking agent of an isocyanate curing agent (e.g., an alcohol-based compound, a phenol-based compound, an oxime-based compound, a lactam-based compound, a pyrazole-based compound, an active methylene compound, etc.).
These blocked isocyanate curing agents may be used alone or in combination of two or more.

A carbodiimide curing agent is a compound containing two or more carbodiimide groups in one molecule. Specific examples of carbodiimide curing agents include poly(4,4'-diphenylmethanecarbodiimide), poly(dicyclohexylmethanecarbodiimide), and poly(diisopropylcarbodiimide). Commercially available carbodiimide curing agents include the "Carbodilite" series manufactured by Nisshinbo Chemical Inc.
These carbodiimide-based curing agents may be used alone or in combination of two or more kinds.

An oxazoline-based curing agent is a compound containing two or more oxazoline groups in one molecule. Specific examples of oxazoline-based curing agents include polyvalent oxazolines such as 2,2'-bis-(2-oxazoline), 2,2'-methylene-bis-(2-oxazoline), and 2,2'-(1,4-phenylene)-bis(2-oxazoline), and polymers or copolymers having oxazoline-group-containing monomer units such as 2-vinyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, and 2-isopropenyl-5-ethyl-2-oxazoline. The oxazoline-group-containing monomers may be used alone or in combination of two or more kinds. In addition, the oxazoline-group-containing monomer may be a copolymer of another monomer that is copolymerizable with the monomer. Commercially available oxazoline-based curing agents include the "Epocross" series manufactured by Nippon Shokubai Co., Ltd.
These oxazoline-based curing agents may be used alone or in combination of two or more kinds.

Epoxy curing agents are compounds containing two or more epoxy groups in one molecule. Specific examples of epoxy curing agents include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, triglycidyl aminophenol, biphenyl diglycidyl ether, triglycidyl isocyanurate, polyglycidyl (meth)acrylate, and copolymers of glycidyl (meth)acrylate and vinyl monomers copolymerizable therewith. Commercially available epoxy curing agents include the "jER" series manufactured by Mitsubishi Chemical Corporation and the "Denacol EX" series manufactured by Nagase Chemtex Corporation.
These epoxy-based curing agents may be used alone or in combination of two or more kinds.

An aziridine-based curing agent is a compound containing two or more aziridine groups in one molecule. Specific examples of aziridine-based curing agents include 2,2-bishydroxymethylbutanol-tris[3-(1-aziridinyl)propionate] and 4,4'-bis(ethyleneiminocarbonylamino)diphenylmethane. Commercially available aziridine-based curing agents include the "ChemiTite" series manufactured by Nippon Shokubai Co., Ltd.
These aziridine-based curing agents may be used alone or in combination of two or more kinds.

When using the aqueous ink composition and the curing agent in combination, it is preferable to mix the two so that the solid content of the curing agent is 0.1 to 10 parts by mass, more preferably 0.3 to 7 parts by mass, and even more preferably 0.5 to 5 parts by mass, per 100 parts by mass of the solid content of the aqueous ink composition. If the ratio of the curing agent is equal to or greater than the lower limit, the curing reaction proceeds sufficiently, and if it is equal to or less than the upper limit, the water resistance of the printed layer is further improved.

<Kit>
A kit according to one embodiment of the present invention independently contains the above-mentioned water-based ink composition of the present invention and the above-mentioned curing agent.
Here, "independently" means that the aqueous ink composition and the curing agent are present in a state where they are not in contact with each other. For example, the kit includes a first container containing the aqueous ink composition and a second container containing the curing agent.

The second container may contain ingredients other than the curing agent (other ingredients).
Examples of other components include solvents and stabilizers.
Examples of the solvent include the aqueous media exemplified above in the description of the aqueous ink composition.

When the kit is used, the water-based ink composition and the curing agent are mixed together.
The mixing ratio when mixing the aqueous ink composition and the curing agent is as described above.

<Laminate>
An example of a laminate according to an embodiment of the present invention is shown in Figures 1 and 2. Note that the dimensional ratios in Figures 1 and 2 are different from the actual ones for the sake of convenience of explanation.
The laminate 10 in FIG. 1 is a printed matter including a substrate 11 and a printed layer 12 provided on one surface of the substrate 11 .
The laminate 20 in Figure 2 is a printed matter comprising a substrate 21, a first printed layer 22 provided on one side of the substrate 21, and a second printed layer 23 provided on the side of the first printed layer opposite the substrate.
When the laminate is attached to a packaging container as a label, it is preferable to attach the base materials 11 and 21 on the outer side of the printed layer 12 and the second printed layer 23, i.e., the printed layer 12 and the second printed layer 23 on the inner side (the side that contacts the packaging container). In addition, when the laminate is used as a packaging material for food or the like, it is preferable to package the base materials 11 and 21 on the inner side of the printed layer 12 and the second printed layer 23, i.e., the printed layer 12 and the second printed layer 23 on the outer side (the side that does not contact the contents).
In addition, another printed layer may be provided on the surface of the substrate 11, 21 by printing a composition containing a matting agent such as a varnish composition or an extender pigment. Here, the surface of the substrate 11 means the surface opposite to the surface of the substrate 11 on which the printed layer 12 is provided. The surface of the substrate 21 means the surface opposite to the surface of the substrate 21 on which the first printed layer 22 is provided. In addition, the surface of the substrate 11 on which the printed layer 12 is provided is the back surface of the substrate 11, and the surface of the substrate 21 on which the first printed layer 22 is provided is the back surface of the substrate 21. In addition, the surface of the printed layer 12 and the second printed layer 23 may be printed with a composition containing a matting agent such as a varnish composition or an extender pigment to provide another printed layer. Here, the surface of the printed layer 12 means the surface opposite to the surface of the printed layer 12 on which the substrate 11 is provided. The surface of the second printed layer 23 means the surface opposite to the surface of the second printed layer 23 on which the printed layer 22 is provided.

<Substrate>
The type of the substrate 11, 21 can be appropriately selected according to the type of the laminate 10, 20, etc., and is not particularly limited, but a plastic substrate or a paper substrate is preferable. For example, when the laminate 10, 20 is used as a paper label, the substrate 11, 12 is preferably a paper substrate. For example, when the laminate 10, 20 is used as a heat-shrinkable label (shrink label), the substrate 11, 21 is preferably a heat-shrinkable film (shrink film). When the laminate 10, 20 is used as a roll label, the substrate 11, 21 is preferably a polyethylene terephthalate (PET) film or a biaxially oriented PP film (OPP film). When the laminate 10, 20 is used as a stretch label, the substrate 11, 21 is preferably a stretch film. Among these, the substrate 11, 21 is preferably a heat-shrinkable film, a polyethylene terephthalate (PET) film, or a biaxially oriented PP film.

Examples of the plastic substrate include polyester films such as polyethylene terephthalate (PET), amorphous polyethylene terephthalate (A-PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), and polylactic acid; polyolefin films such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), and polypropylene (PP); cellulose films such as cellophane; polystyrene (PS) films; ethylene-vinyl acetate copolymer resin films; ethylene-vinyl alcohol copolymer resin films; polyamide (Ny) films; polycarbonate films; polyimide films; and polyvinyl chloride films. These films can be appropriately selected depending on the application. For example, when the laminates 10 and 20 are used as heat-shrinkable labels (shrink labels), the substrates 11 and 21 are preferably uniaxially shrinkable polystyrene films, uniaxially shrinkable PET films, uniaxially shrinkable polyolefin films, and uniaxially shrinkable polyvinyl chloride films.
For example, any of oriented and unoriented plastic films such as biaxially oriented PP film and unoriented PP film can be used as the substrates 11 and 21. The surfaces of the substrates 11 and 21 may be subjected to surface treatment such as corona discharge treatment, plasma treatment, frame treatment, and solvent treatment.

The substrates 11 and 21 may have a single layer structure or a laminate structure. That is, the substrates 11 and 21 may be single layer films or laminate films. When the substrates 11 and 21 are laminate films, they may be configured by laminating two or more films of the same type, or by laminating two or more films of different types. Examples of preferred film combinations include a combination in which a polyester film is on the front side of the substrates 11 and 21 and a polystyrene film or a polyolefin film is on the back side of the substrates 11 and 21, a cyclic polyolefin film is on the front side of the substrates 11 and 21, and a polyethylene film or a polypropylene film is on the back side of the substrates 11 and 21, and the like.

The thickness of the substrates 11 and 21 is preferably 5 to 100 μm, more preferably 12 to 60 μm, and even more preferably 12 to 50 μm.

<Printed Layer, Second Printed Layer>
In the laminate 10, the printed layer 12 is provided on one surface of the substrate 11. In the laminate 20, the second printed layer 23 is provided on the surface opposite to the substrate 21 of the first printed layer 22 provided on one surface of the substrate 21.
The printed layer 12 and the second printed layer 23 are printed layers (W) formed using the water-based ink or kit of the present embodiment described above. In the present invention, the printed layer 12, which is the printed layer (W) formed using the water-based ink or kit, is also referred to as the "printed coating (W)" and the second printed layer 23 is also referred to as the "second printed coating (W)".
The thickness of the printed layer 12 and the second printed layer 23 is preferably 0.2 to 3.0 μm, more preferably 0.3 to 2.0 μm, and even more preferably 0.3 to 1.5 μm.

<First Printing Layer>
In the laminate 20 , the first printed layer 22 is provided on one surface of the substrate 21 .
The first printed layer 22 is a printed layer (C) (hereinafter also referred to as "color printed layer (C)" or "printed coating film (C)") formed using an ink composition for the purpose of imparting design, functionality, etc. to the laminate 20.
The first printed layer 22 may have a single-layer structure or a laminated structure.
The total thickness of the first printed layer 22 is preferably 0.2 to 15 μm, more preferably 0.3 to 10 μm, and even more preferably 0.3 to 8 μm.

The ink composition used to form the first print layer 22 contains a color pigment. The ink composition is preferably an aqueous ink composition.
The aqueous ink composition is not particularly limited, and any known composition can be used. For example, the aqueous ink composition may include a composition containing an aqueous binder resin, an aqueous medium, a color pigment, and other components as necessary.
As the aqueous binder resin, any aqueous binder resin known in the art can be used.
Examples of the aqueous medium include the aqueous media exemplified above in the description of the aqueous ink composition of the present invention.
Examples of color pigments include organic pigments such as azo pigments (monoazo, condensed azo, etc.), threne pigments (anthraquinone, perinone, perylene, thioindigo, etc.), phthalocyanine pigments (phthalocyanine blue, phthalocyanine green, etc.), quinacridone pigments, dioxazine pigments, isoindolinone pigments, pyrrolopyrrole pigments, aniline black, and organic fluorescent pigments; and inorganic pigments such as natural products (clay, etc.), ferrocyanides (princess blue, etc.), sulfides (zinc sulfide, etc.), sulfates, oxides (chromium oxide, zinc oxide, iron oxide, etc.), hydroxides (aluminum hydroxide, etc.), silicates (ultramarine, etc.), carbonates, carbon (carbon black, graphite, etc.), metal powders (aluminum powder, bronze powder, zinc powder, etc.), and calcined pigments. Examples of color pigments include the above-mentioned titanium oxide and precipitated barium sulfate.
Examples of other components include waxes, dispersants, antifoaming agents, lubricants, pH adjusters, and thickeners.

<Method of manufacturing laminate>
The method for producing the laminate 10 in FIG. 1 includes a step of forming a printed layer 12 on one surface of a substrate 11 using the water-based ink or kit of this embodiment.
The manufacturing method of the laminate 20 in Figure 2 includes a step (1) of forming a first printed layer 22 on one side of a substrate 21 using an ink composition, and a step (2) of forming a second printed layer 23 on the side of the first printed layer 22 opposite the substrate 21 using the water-based ink or kit of this embodiment.

In the method for producing the laminate 10 in FIG. 1, for example, the water-based ink of the present embodiment is applied onto one surface of the substrate 11 and dried to form the printed layer 12 .
When forming the printed layer 12 using the kit of this embodiment, the aqueous ink and the curing agent included in the kit are mixed to prepare a mixture (M), and the obtained mixture (M) is applied onto one surface of the substrate 11 and dried to form the printed layer 12. The mixing ratio when mixing the aqueous ink and the curing agent is as described above.
In addition, after the water-based ink or mixture (M) is applied to one surface of the substrate 11 and dried to form the printed layer 12, further water-based ink or mixture (M) may be applied (recoated).

The method for applying the aqueous ink or mixture is not particularly limited, and any known application method can be used, such as gravure printing, flexographic printing, brush application, gravure coater method, die coater method, bar coater method, spray coating method, flow coating method, dip coating method, spin coating method, and curtain coating method. Among these, flexographic printing is preferred because of its high quality and productivity.

The drying method is not particularly limited as long as it can remove the aqueous medium contained in the aqueous ink or mixture coated on one side of the substrate 11, but examples of the drying method include reduced pressure drying, pressure drying, heat drying, and air drying.
The heating temperature is preferably from 30 to 150°C, and more preferably from 40 to 120°C.

The method for producing the laminate 20 in FIG. 2 includes the above-mentioned steps (1) and (2) in this order.
In step (1), for example, an ink composition is applied onto one surface of the substrate 21 and dried to form a first printed layer 22. In step (2), for example, the water-based ink of this embodiment is applied onto the surface of the first printed layer 22 opposite the substrate 21 and dried to form a second printed layer 23. As in the method for producing the laminate 10, the kit of this embodiment may be used instead of the water-based ink.
The step (1) may be carried out once or twice or more. That is, the ink composition may be applied in multiple layers.
The step (2) may be carried out once or twice or more. That is, the aqueous ink composition or mixture (M) may be applied in multiple coats.
As the coating method and drying method in steps (1) and (2), the same methods as those used in the production method of the laminate 10 can be applied.

<Applications>
The laminates 10 and 20 can be used as various labels such as plastic labels attached to packaging containers for beverages, foods such as prepared dishes and bento boxes, daily necessities such as cosmetics, etc. Among these, the laminates 10 and 20 are particularly suitable as labels for foods and beverages.
In particular, when the base materials 11, 21 constituting the laminates 10, 20 are heat-shrinkable films, they are suitable as shrink labels.

<Other embodiments>
The laminate is not limited to the above-described embodiment.
For example, in the case of the laminate 10 shown in Fig. 1, the printed layer 12 is provided over the entirety of one surface of the substrate 11, but the printed layer 12 may be provided over a portion of one surface of the substrate 11. In this case, it is preferable that another printed layer is provided in the region of one surface of the substrate 11 where the printed layer 12 is not provided. Examples of the other printed layer include a layer formed from a varnish composition.
Similarly, in the case of the laminate 20 shown in Fig. 2, the second printed layer 23 is provided over the entirety of one surface of the first printed layer 22, but the second printed layer 23 may be provided over a portion of one surface of the first printed layer 22. In this case, it is preferable that another printed layer is provided in the area of one surface of the first printed layer 22 where the second printed layer 23 is not provided. Examples of the other printed layer include a layer formed from a varnish composition.

1, another printed layer may be provided on the surface of the printed layer 12 opposite the substrate 11. The other printed layer may be, for example, a layer formed from a varnish composition.
Similarly, in the case of the laminate 20 shown in Fig. 2, another printed layer may be provided on the surface of the second printed layer 23 opposite to the first printed layer 22. The other printed layer may be, for example, a layer formed from a varnish composition.

<Labels and packaging>
A label according to an embodiment of the present invention includes the laminate according to the present embodiment described above. A label may be made of the laminate according to the present embodiment described above.
A package according to an embodiment of the present invention includes the laminate according to the present embodiment described above. The package may be made of the laminate according to the present embodiment described above.

The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to the following examples as long as it does not exceed the gist of the invention.

[Ingredients used]
As the acrylic emulsion resin (A), the compound shown below was used.
A-1: Acrylic emulsion resin (manufactured by Seiko PMC Corporation, product name "Hiros-X-KE-1148", glass transition temperature 21°C, acid value 31 mgKOH/g, solid content 43% by mass).
A-2: Styrene-acrylic copolymer emulsion resin (manufactured by Seiko PMC Corporation, product name "Hiros-X-J-140A", glass transition temperature 6°C, acid value 33 mgKOH/g, solid content 41% by mass).
A-3: Acrylic emulsion resin (manufactured by Covestro Coating Resins, product name "Neocryl XK-110", glass transition temperature 48°C, acid value 15 mgKOH/g, solid content 46% by mass).
a-1: styrene-acrylic copolymer emulsion resin (manufactured by BASF Japan, product name "Joncryl PDX-7158", glass transition temperature 55°C, acid value 54 mgKOH/g, solid content 41% by mass).
a-2: styrene-acrylic copolymer emulsion resin (manufactured by BASF Japan, product name "Joncryl PDX-7630A", glass transition temperature 53°C, acid value 200 mgKOH/g, solid content 32% by mass).
In addition, since a-1 and a-2 have an acid value of 40 mgKOH/g or more, they correspond to the acrylic emulsion resin (B).

As the acrylic emulsion resin (B), the compound shown below was used.
b-1: Styrene-acrylic copolymer emulsion resin (manufactured by Covestro Coating Resins, product name "Neocryl A-662", glass transition temperature 95°C, acid value 24 mgKOH/g, solid content 40% by mass).
b-2: Acrylic emulsion resin (manufactured by Covestro Coating Resins, product name "Neocryl XK-12", glass transition temperature 21°C, acid value 11 mgKOH/g, solid content 45% by mass).
B-1: Acrylic emulsion resin (manufactured by Seiko PMC Corporation, product name "Hiros-X-ME-2039", glass transition temperature 8°C, acid value 42 mgKOH/g, solid content 48.5% by mass).
B-2: Styrene-acrylic copolymer emulsion resin (manufactured by Seiko PMC Corporation, product name "Hiros-X-PE-2109", glass transition temperature -10°C, acid value 53 mgKOH/g, solid content 49.5% by mass).
B-3: Acrylic emulsion resin (manufactured by Seiko PMC Corporation, product name "Hiros-X-PE-1126", glass transition temperature -12°C, acid value 50 mgKOH/g, solid content 41.5% by mass).
B-4: Styrene-acrylic copolymer emulsion resin (manufactured by BASF Japan, product name "Joncryl PDX-7734", glass transition temperature 40°C, acid value 89 mgKOH/g, solid content 41.4% by mass).
B-5: Styrene-acrylic copolymer emulsion resin (manufactured by BASF Japan, product name "Joncryl PDX-7630A", glass transition temperature 53°C, acid value 200 mgKOH/g, solid content 32% by mass).
In addition, b-1 and b-2 correspond to the acrylic emulsion resin (A) because the acid value is less than 40 mgKOH/g. Also, a-2 and B-5 are the same resin.

As other resins, the compounds shown below were used.
B'-1: Water-soluble acrylic resin (manufactured by BASF Japan, product name "Joncryl JDX-6180", weight average molecular weight 14,000, glass transition temperature 134°C, acid value 230 mgKOH/g, solids content 27% by mass).

The following compounds were used as titanium oxide and precipitated barium sulfate.
Titanium oxide: titanium oxide having a rutile crystal structure (manufactured by Ishihara Sangyo Kaisha, Ltd., product name "CR-90", oil absorption 21 mL/100 g, average particle size: 0.25 μm, solid content 100% by mass).
Precipitated barium sulfate: precipitated barium sulfate particles (manufactured by Sakai Chemical Industry Co., Ltd., product name "Precipitated Barium Sulfate 200", average particle size: 0.8 μm, solid content 100% by mass).

Resin beads: Micropearl EX-002 (manufactured by Sekisui Chemical Co., Ltd., average particle size: 2 μm, solid content 100% by mass).
Silicone resin: TEGO Glide 410 (manufactured by Evonik, solid content 100% by mass).
Dispersant: SN Dispersant 2010 (manufactured by San Nopco Limited, solid content 30% by mass).
・pH adjuster: ammonia water.
Defoamer: BYK-1719 (manufactured by BYK Corporation, solid content 100% by mass).
- Thickener: SN Thickener 612 (manufactured by San Nopco, solid content 30% by mass).
Surfactant: BYK-3480 (manufactured by BYK Corporation, solid content 100% by mass).
- Aqueous medium: water.
- Aqueous medium: isopropanol.

[Evaluation method]
(Evaluation of pigment dispersibility)
The aqueous ink composition was stored at 40° C. for 14 days, after which it was confirmed whether or not there was any increase in viscosity or any occurrence of aggregates.
In addition, an OPP film (trade name "FOR", manufactured by Futamura Chemical Co., Ltd., thickness 25 μm) was used as the substrate, and the aqueous ink composition was applied to the substrate by flexographic printing using a flexographic hand proofer as an applicator so that the coating amount after drying was 1.0 g/ ^m2 . The composition was then dried for 1 minute with hot air from a dryer to form a printed layer (coating film). The state of the coating film was visually confirmed. Pigment dispersibility was evaluated according to the following criteria. In the case of ○, there is practical use.
◯: The coating film has good hiding power and smoothness. The ink does not thicken or form aggregates over time.
△: The coating film has poor hiding power or smoothness. The ink thickens slightly over time, but no coagulation occurs.
×: Either the hiding power or the smoothness of the coating film, or both, are very poor. The ink thickens over time and aggregates are generated.

(Evaluation of Viscosity Stability)
The aqueous ink composition was visually inspected and filtered through a 100 mesh wire screen to confirm that it was in a homogeneous liquid state. The viscosity was also measured using a Zahn Cup No. 5 manufactured by Rigo Co., Ltd. The fluidity was evaluated according to the following criteria. In the case of ○, it is practical.
◯: The aqueous ink composition was in a homogeneous liquid state, and no aggregates were formed even when filtered through a 100 mesh wire screen, and the viscosity could be measured without problems using a Zahn Cup No. 5 manufactured by Rigo Co., Ltd., and the measured viscosity value was 30 seconds or less.
×: The aqueous ink composition was gelled in whole or in part, or aggregates were observed when filtered through a 100 mesh wire screen, or even if the aqueous ink composition was in a homogeneous liquid state, the viscosity was increased and the measured viscosity using a Zahn Cup No. 5 manufactured by Rigo Co., Ltd. was more than 30 seconds, or the viscosity was impossible to measure.

(Evaluation of Adhesion to Substrate)
As in the evaluation of pigment dispersibility, a printed layer (coating film) was formed on a substrate. After a certain period of time had passed, a 18 mm wide cellophane tape (manufactured by Nichiban Co., Ltd.) was attached to the surface of the printed layer and pressed with a finger, and then the cellophane tape was quickly peeled off, and the state of the coating layer remaining on the substrate was visually confirmed.
The ratio of the area of the peeled printed layer to the adhesive area of the cellophane tape (peeling ratio) was determined, and the adhesion of the coating layer was evaluated according to the following criteria: ⊚, ◯, and △: Practical.
⊚: The coating film did not peel off at all (peeling rate: 0%).
A: The peeling rate was more than 0% and less than 20%.
Δ: The peeling rate was 20% or more and less than 50%.
x: Peeling rate is 50% or more.

(Evaluation of wear resistance)
As in the evaluation of pigment dispersibility, a printed layer (coating film) was formed on a substrate. The printed layer of the obtained laminate was rubbed with a friction cloth using a Gakushin-type friction fastness tester (manufactured by Tester Sangyo Co., Ltd., product name "AB-301"). A No. 3 gold cloth was used as the friction cloth. The friction test conditions were a friction area of 24 cm ² , a load of 500 gf, and 100 round trips of friction. After the friction was completed, the state of the printed layer that had fallen off (wear state) was visually observed, and the ratio of the area of the printed layer that had fallen off to the friction area (falling ratio) was determined and evaluated according to the following criteria. ◎, ○, and △ indicate practical use.
⊚: The coating film did not fall off at all (falling off rate: 0%).
◯: The rate of falling off is less than 20% and the substrate is not torn.
Δ: The percentage of fallen off is 20% or more and less than 50%, and the substrate is not torn.
x: The percentage of fallen off is 50% or more, or the substrate is torn.

(Evaluation of Water Abrasion Resistance)
As in the evaluation of pigment dispersibility, a printed layer (coating film) was formed on a substrate. The printed layer of the obtained laminate was rubbed with a friction cloth moistened with water using a Gakushin-type friction fastness tester (manufactured by Tester Sangyo Co., Ltd., product name "AB-301"). A No. 3 gold cloth was used as the friction cloth. The friction test conditions were a friction area of 24 cm ² , a load of 200 gf, and 100 round trips of friction. After the friction was completed, the state of the printed layer that had fallen off (wear state) was visually observed, and the ratio of the area of the printed layer that had fallen off to the friction area (falling ratio) was determined and evaluated according to the following criteria. ◎, ○, and △ indicate practical use.
⊚: The coating film did not fall off at all (falling off rate: 0%).
◯: The rate of falling off is less than 20% and the substrate is not torn.
Δ: The percentage of fallen off is 20% or more and less than 50%, and the substrate is not torn.
x: The percentage of fallen off is 50% or more, or the substrate is torn.

(Evaluation of Scratch Resistance)
As in the evaluation of pigment dispersibility, a printed layer (coating film) was formed on a substrate. The printed layer of the obtained laminate was rubbed back and forth with a fingernail about 20 times. After rubbing, the state of the printed layer falling off was visually observed, and the ratio of the area of the fallen printed layer to the friction area (falling ratio) was calculated and evaluated according to the following criteria. ◎, ○, and △ are practical.
⊚: The coating film did not fall off at all (falling off rate: 0%).
◯: The rate of falling off is less than 20% and the substrate is not torn.
Δ: The percentage of fallen off is 20% or more and less than 50%, and the substrate is not torn.
x: The percentage of fallen off is 50% or more, or the substrate is torn.

(Evaluation of heat resistance)
As in the evaluation of pigment dispersibility, a printed layer (coating film) was formed on a substrate. The printed layer immediately after printing was dried with a dryer for 10 seconds, and then aluminum foil was placed on the surface (printed surface) of the printed layer, and heat sealing was performed for 1 second at a load of 2 kg/ ^cm2 using a heat seal tester (manufactured by Tester Sangyo Co., Ltd., product name "TP-701-C Heat Seal Tester"). The heat sealing temperature ranged from 80°C to 160°C in 20°C increments. Thereafter, the aluminum foil was peeled off, and the heat resistance of the printed layer was evaluated according to the following evaluation criteria. ◎, ○, and △ indicate practical use.
⊚: The printing layer was not transferred to the aluminum foil at all.
◯: The proportion of the area of the printed layer transferred to the aluminum foil was 10% or more and less than 30%.
Δ: The area ratio of the printed layer transferred to the aluminum foil is 30% or more and less than 50%.
×: The area ratio of the printed layer transferred to the aluminum foil is 50% or more.

[Examples 1 to 14, Comparative Examples 1 to 10]
<Preparation of Water-Based Ink Composition>
A mill base composition was obtained by mixing acrylic emulsion resin (A), acrylic emulsion resin (B), or other resin with either or both of titanium oxide and precipitated barium sulfate, and optional ingredients according to the formulations shown in Tables 1 and 2. To the obtained mill base composition, acrylic emulsion resin (A) or acrylic emulsion resin (B), and optional ingredients were added and mixed according to the formulations shown in Tables 1 and 2, to obtain an aqueous ink composition.
The numerical values relating to the blending amounts in Tables 1 and 2 refer to parts by mass. A blank space means that the component is not blended (blended amount 0 parts by mass). The blending amounts include volatile matters. "Aem" in Tables 1 and 2 refers to acrylic emulsion resin.
The resulting aqueous ink composition was evaluated for pigment dispersibility, viscosity stability, adhesion to substrate, abrasion resistance, water abrasion resistance, scratch resistance, and heat resistance. The results are shown in Tables 1 and 2.

As shown in Table 1, the aqueous ink compositions obtained in each Example had excellent pigment dispersibility and viscosity stability. In addition, the resulting printed layer had excellent substrate adhesion, abrasion resistance, water abrasion resistance, scratch resistance, and heat resistance. Comparative Examples 1 to 5 and 8 are examples that do not contain either the acrylic emulsion resin (A) or the acrylic emulsion resin (B). The printed layer obtained from the aqueous ink composition of Comparative Example 1, which does not contain the acrylic emulsion resin (A), was poor in scratch resistance. The printed layers obtained from the aqueous ink compositions of Comparative Examples 2 and 3, which do not contain the acrylic emulsion resin (B), were poor in substrate adhesion. The printed layer obtained from the aqueous ink composition of Comparative Example 4, which does not contain the acrylic emulsion resin (A), was poor in scratch resistance. The printed layer obtained from the aqueous ink composition of Comparative Example 5, which does not contain the acrylic emulsion (A), was poor in substrate adhesion and water abrasion resistance. The aqueous ink composition of Comparative Example 6, in which the total content of the acrylic emulsion resin (A) and the acrylic emulsion resin (B) was less than 15% by mass, had poor viscosity stability. The resulting printed layer also had poor scratch resistance. The printed layer obtained from the aqueous ink composition of Comparative Example 7, in which the total content of the acrylic emulsion resin (A) and the acrylic emulsion resin (B) was more than 40% by mass, had poor heat resistance. The aqueous ink composition of Comparative Example 8, which did not contain the acrylic emulsion resin (A), had poor viscosity stability. The resulting printed layer also had poor scratch resistance. The printed layer obtained from the aqueous ink composition of Comparative Example 9, in which the mass ratio of the acrylic emulsion resin (A):acrylic emulsion resin (B) was 1:0.80, had poor abrasion resistance. The aqueous ink composition of Comparative Example 10, in which the mass ratio of the acrylic emulsion resin (A):acrylic emulsion resin (B) was 1:50.65, had poor viscosity stability.

(Application example)
The laminate 20 described above also showed excellent evaluation results similar to those of Examples 1 to 14.

10 Laminate 11 Substrate 12 Printed layer (Printed layer (W))
20 Laminate 21 Substrate 22 First printed layer (color printed layer (C))
23 Second printed layer (printed layer (W))

Claims (12)

An acrylic emulsion resin (A) (excluding water-soluble acrylic resins) ,
An acrylic emulsion resin (B) (excluding water-soluble acrylic resins) ,
An aqueous ink composition comprising titanium oxide and/or precipitated barium sulfate,
The acid value of the acrylic emulsion resin (A) is less than 40 mgKOH/g,
The acid value of the acrylic emulsion resin (B) is 40 mgKOH/g or more and 250 mgKOH/g or less,
a total content of the solid contents of the acrylic emulsion resin (A) and the acrylic emulsion resin (B) relative to a total mass of the solid contents of the aqueous ink composition is 15 to 40 mass%,
a mass ratio of a solid content of the acrylic emulsion resin (A) to a solid content of the acrylic emulsion resin (B) is acrylic emulsion resin (A):acrylic emulsion resin (B)=1:1.0 to 1:40. The aqueous ink composition according to claim 1, wherein the glass transition temperature of the acrylic emulsion resin (A) is -20 to 60°C, and the glass transition temperature of the acrylic emulsion resin (B) is -20 to 60°C. The aqueous ink composition according to claim 1 for use with a curing agent. The aqueous ink composition according to claim 1, further comprising resin beads. The aqueous ink composition according to claim 4, wherein the resin beads have an average particle size of 0.5 to 8 μm. The aqueous ink composition according to claim 1, further comprising a silicone resin. The water-based ink composition according to claim 6, wherein the silicone-based resin is at least one selected from the group consisting of amine-modified silicone, silicone-modified acrylic, and polyether-modified silicone. An aqueous ink comprising the aqueous ink composition according to any one of claims 1 to 7. The water-based ink according to claim 8, which is for use on plastic or paper substrates. A laminate comprising a substrate and a printed layer formed on at least one surface of the substrate using the aqueous ink according to claim 8, the substrate being a plastic substrate or a paper substrate. A label comprising the laminate of claim 10. A package comprising the laminate according to claim 10.

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