Water-based gravure printing ink composition for paper containers and printed matter

Abstract

The present invention provides an aqueous gravure printing ink composition for paper containers that has excellent drying properties, gloss, blocking resistance, whiteout prevention, resolubility, and leveling properties (suitability for overprinting), and a printed product. The present invention also provides an aqueous gravure printing ink composition for paper containers that uses a large amount of carbon-neutral raw materials, and a printed product. [Solution] An aqueous gravure printing ink composition for paper containers, comprising a pigment, a hydroxyl group-containing styrene-acrylic resin emulsion, a pigment dispersion resin, a hyperbranched polyether wetting agent, and an aqueous medium, wherein the content of the hyperbranched polyether wetting agent in the aqueous gravure printing ink composition for paper containers is 0.03 to 1.5 mass%.

Description

[Technical Field]

[0001] The present invention relates to a water-based gravure printing ink composition for paper containers and a printed matter. [Background technology]

[0002] Conventionally, water-based inks have been printed by gravure printing for decorative purposes on the outer packaging of various products ranging from food products such as confectionery, tissues, and detergents to household goods, and on multi-pack packaging for alcoholic beverages and drinks (see Patent Documents 1 and 2). However, the ink compositions described in Patent Documents 1 and 2 have room for improvement in drying properties, blocking resistance, leveling properties, and the like.

[0003] Therefore, it has been proposed that the drying property, blocking resistance, and leveling property can be improved by using a specific amount of a hyperbranched polyether type wetting agent in combination with a specific printing modifier in an aqueous gravure printing ink composition for paper containers (see, for example, Patent Document 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-144334 [Patent Document 2] Japanese Patent Application Publication No. 2017-128701 [Patent Document 3] Japanese Patent Publication No. 2020-66653 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, there has been a growing demand for better drying properties, gloss, anti-blocking properties, prevention of white spots, resolubility, and leveling properties (suitability for overprinting).

[0006] In addition, environmental initiatives are becoming more active, and the packaging industry is also being called upon to create inks that can reduce carbon dioxide emissions (become carbon neutral) by using raw materials that are not derived from fossil fuels, such as plant- and animal-derived materials.

[0007] The present invention has been made in view of the above-mentioned conventional problems, and aims to provide an aqueous gravure printing ink composition for paper containers and a printed product thereof that are excellent in drying speed, gloss, blocking resistance, prevention of white voids, resolubility, and leveling properties (suitability for overprinting). Another aim is to provide an aqueous gravure printing ink composition for paper containers and a printed product thereof that uses a large amount of carbon-neutral raw materials. [Means for solving the problem]

[0008] As a result of intensive research aimed at solving the above-mentioned problems, the present inventors have found that the following aqueous gravure printing ink composition for paper containers and printed matter can solve the above-mentioned problems, and have thus completed the present invention. The aqueous gravure printing ink composition for paper containers and printed matter of the present invention, which solve the above-mentioned problems, mainly comprise the following components.

[0009] (1) An aqueous gravure printing ink composition for paper containers, comprising a pigment, a hydroxyl group-containing styrene-acrylic resin emulsion, a pigment dispersion resin, a hyperbranched polyether wetting agent, and an aqueous medium, wherein the content of the hyperbranched polyether wetting agent in the aqueous gravure printing ink composition for paper containers is 0.03 to 1.5 mass%.

[0010] According to this configuration, the aqueous gravure printing ink composition for paper containers has excellent drying properties, gloss, blocking resistance, prevention of white spots, resolubility, and leveling properties (suitability for overprinting).

[0011] (2) The aqueous gravure printing ink composition for paper containers according to (1), wherein the hydroxyl group-containing styrene-acrylic resin emulsion has a core-shell structure, and the core-shell structure has, in at least one of the shell portion and the core portion, a structural unit derived from a (meth)acrylate having an aliphatic alkyl group having 4 to 24 carbon atoms and a structural unit derived from a (meth)acrylate having a hydroxy group.

[0012] According to this configuration, the aqueous gravure printing ink composition for paper containers has superior leveling properties, prevention of white spots, resolubility, and ink storage stability.

[0013] (3) The aqueous gravure printing ink composition for paper containers according to (1) or (2), which contains a silicone-based leveling agent.

[0014] According to this configuration, the aqueous gravure printing ink composition for paper containers has better leveling properties (suitability for overprinting).

[0015] (4) The aqueous gravure printing ink composition for paper containers according to any one of (1) to (3), which contains a rosin-based emulsion.

[0016] According to this configuration, the aqueous gravure printing ink composition for paper containers is not derived from fossil fuels, but uses raw materials derived from plants and animals, making it possible to reduce carbon dioxide emissions (become carbon neutral).

[0017] (5) The aqueous gravure printing ink composition for paper containers according to (2), wherein the (meth)acrylate having a hydroxy group is 2-hydroxyethyl (meth)acrylate.

[0018] According to this configuration, the aqueous gravure printing ink composition for paper containers has superior leveling properties, prevention of white spots, resolubility, and ink storage stability.

[0019] (6) The aqueous gravure printing ink composition for paper containers according to any one of (1) to (5), wherein the pigment dispersion resin comprises an alkali-soluble water-soluble resin.

[0020] According to this configuration, the aqueous gravure printing ink composition for paper containers has better dispersibility of the colorant, ink storage stability, and resolubility.

[0021] (7) The aqueous gravure printing ink composition for paper containers according to any one of (1) to (6), wherein the pigment dispersing resin contains an (ethylene oxide / propylene oxide) block polymer.

[0022] According to this configuration, the aqueous gravure printing ink composition for paper containers has better dispersibility of the colorant, ink storage stability, and resolubility.

[0023] (8) A printed matter printed with the aqueous gravure printing ink composition for paper containers according to any one of (1) to (7).

[0024] With this configuration, the printed matter uses many raw materials that can be carbon neutral, has excellent gloss, has few white spots, and can be overprinted. [Effects of the Invention]

[0025] According to the present invention, it is possible to provide an aqueous gravure printing ink composition for paper containers and a printed matter that exhibit excellent drying properties, gloss, blocking resistance, whiteout prevention, resolubility, and leveling properties (suitability for overprinting).Furthermore, it is possible to provide an aqueous gravure printing ink composition for paper containers and a printed matter that use a large amount of carbon-neutral raw materials. DETAILED DESCRIPTION OF THE INVENTION

[0026] <Water-based gravure printing ink composition for paper containers> An aqueous gravure printing ink composition for paper containers (hereinafter also referred to as ink composition) according to one embodiment of the present invention contains a pigment, a hydroxyl group-containing styrene-acrylic resin emulsion, a pigment dispersion resin, a hyperbranched polyether wetting agent, and an aqueous medium. The content of the hyperbranched polyether wetting agent in the ink composition is 0.03 to 1.5% by mass. Each of these components will be described below.

[0027] In the present embodiment, the acid value is a value measured in accordance with JIS K 2501:2003, and the glass transition temperature (Tg) is a value measured in accordance with JIS K 7121:2012.

[0028] (pigment) The pigment may be any pigment conventionally used in aqueous gravure printing ink compositions. Specific examples of the inorganic pigment include titanium oxide, red iron oxide, antimony red, cadmium yellow, cobalt blue, Prussian blue, ultramarine blue, carbon black, and graphite. Titanium oxide is preferably surface-treated with silica and / or alumina. Examples of the organic pigment include soluble azo pigments, insoluble azo pigments, azo lake pigments, condensed azo pigments, copper phthalocyanine pigments, and condensed polycyclic pigments. Pigments may be used in combination.

[0029] The pigment content is not particularly limited. For example, the pigment content is preferably 1.0% by mass or more, and more preferably 3.0% by mass or more, of the total solid content of the ink composition. Furthermore, the pigment content is preferably 60.0% by mass or less, of the total solid content of the ink composition. When the pigment is an organic pigment or carbon black, the pigment content is preferably 1.0% by mass or more, and more preferably 3.0% by mass or more. When the pigment is an organic pigment or carbon black, the pigment content is preferably 35.0% by mass or less, and more preferably 30.0% by mass or less.

[0030] (Hydroxyl group-containing styrene-acrylic resin emulsion) The hydroxyl group-containing styrene-acrylic resin emulsion is not particularly limited. As an example, the hydroxyl group-containing styrene-acrylic resin emulsion is preferably a hydroxyl group-containing styrene-acrylic resin emulsion having a core-shell structure. This allows the ink composition to have better leveling properties, drying properties, resolubility, coating film resistance such as abrasion resistance, ink storage stability, and white void prevention properties.

[0031] ·Hydroxyl group-containing styrene-acrylic resin emulsion with a core-shell structure The hydroxyl group-containing styrene-acrylic resin emulsion having a core-shell structure preferably has, in at least one of the shell portion or the core portion, a structural unit derived from a (meth)acrylate having an aliphatic alkyl group with 4 to 24 carbon atoms and a structural unit derived from a (meth)acrylate having a hydroxy group. The structural unit derived from a (meth)acrylate having an aliphatic alkyl group with 4 to 24 carbon atoms is preferably present in the shell portion and the core portion. The structural unit derived from a (meth)acrylate having a hydroxy group is preferably present in the shell portion. This provides the ink composition with superior leveling properties, drying properties, resolubility, coating film resistance, ink storage stability, and white void prevention properties.

[0032] The mass ratio of the core part to the shell part is preferably shell part:core part=10:90 to 70:30, more preferably 30:70 to 70:30, and even more preferably 40:60 to 60:40. When the mass ratio of the core part to the shell part is within the above range, the ink composition has excellent printability such as leveling properties, drying properties, doctor release properties, and prevention of white voids, and also has good coating film properties and ink storage stability.

[0033] The hydroxyl group-containing styrene-acrylic resin emulsion having a core-shell structure preferably has, in at least one of the shell portion and the core portion, a structural unit derived from a (meth)acrylate having an aliphatic alkyl group with 4 to 8 carbon atoms and a structural unit derived from a (meth)acrylate having a hydroxy group.

[0034] Furthermore, the styrene-acrylic resin emulsion is preferably a film-forming emulsion at room temperature obtained by copolymerizing a styrene-based monomer, a (meth)acrylate having an aliphatic alkyl group having 4 to 24 carbon atoms, and, if necessary, a (meth)acrylate other than a (meth)acrylate having an aliphatic alkyl group having 4 to 24 carbon atoms and a (meth)acrylate having a hydroxyl group, using a water-soluble acrylic resin that becomes the shell portion of a hydroxyl group-containing styrene-acrylic resin emulsion having a core-shell structure as a polymer emulsifier, and the copolymerization of the styrene-based monomer, a (meth)acrylate having an aliphatic alkyl group having 4 to 24 carbon atoms, and the (meth)acrylate having a hydroxyl group.

[0035] The (meth)acrylate having an aliphatic alkyl group having 4 to 24 carbon atoms is not particularly limited. Examples of (meth)acrylates having an aliphatic alkyl group having 4 to 24 carbon atoms include butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, lauryl (meth)acrylate, oleyl (meth)acrylate, and eicosyl (meth)acrylate. The (meth)acrylate having an aliphatic alkyl group having 4 to 24 carbon atoms preferably includes at least one of butyl acrylate and 2-ethylhexyl (meth)acrylate.

[0036] The (meth)acrylate having a hydroxy group is not particularly limited. For example, the (meth)acrylate having a hydroxy group is a (meth)acrylic acid ester compound having a hydroxyalkyl group, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, or 3-hydroxypropyl (meth)acrylate. The (meth)acrylate having a hydroxy group is preferably 2-hydroxyethyl (meth)acrylate, and a structural unit derived therefrom is more preferably present in the shell.

[0037] Shell The shell portion is formed by using a water-soluble acrylic resin that will become the shell portion as a polymer emulsifier. Specifically, the shell portion contains structural units derived from a (meth)acrylate having an aliphatic alkyl group with 4 to 24 carbon atoms, structural units derived from a (meth)acrylate having a hydroxy group, structural units derived from a carboxyl group-containing monomer, and structural units derived from a (meth)acrylate other than a (meth)acrylate having an aliphatic alkyl group with 4 to 24 carbon atoms and a (meth)acrylate having a hydroxy group, and preferably has a theoretical acid value of 40 to 120 mgKOH / g. In Table 1 below, the shell portion is formed from a polymer emulsifier.

[0038] The carboxyl group-containing monomer is not particularly limited. Examples of the carboxyl group-containing monomer include maleic acid monoester compounds having an aliphatic hydrocarbon group having 8 to 13 carbon atoms, such as acrylic acid, methacrylic acid, maleic acid (anhydride), monomethyl maleate, monoethyl maleate, monobutyl maleate, monohexyl maleate, monooctyl maleate, mono-2-ethylhexyl maleate, and monolauryl maleate, maleic acid monoester compounds having an aliphatic hydrocarbon group having 14 to 20 carbon atoms, such as monomyristyl maleate, monocetyl maleate, monostearyl maleate, monooleyl maleate, and monoeicosyl maleate, crotonic acid and its ester compounds, and itaconic acid and its ester compounds.

[0039] The (meth)acrylates other than (meth)acrylates having an aliphatic alkyl group having 4 to 24 carbon atoms and (meth)acrylates having a hydroxy group are not particularly limited. Examples of (meth)acrylates other than (meth)acrylates having an aliphatic alkyl group having 4 to 24 carbon atoms and (meth)acrylates having a hydroxy group include (meth)acrylates having an aliphatic hydrocarbon group such as methyl (meth)acrylate, ethyl (meth)acrylate, and propyl (meth)acrylate, (meth)acrylamide, acrylonitrile, olefin-based compounds, styrene-based monomers such as styrene, α-methylstyrene, vinyltoluene, dimethylstyrene, ethylstyrene, isopropylstyrene, t-butylstyrene, chlorostyrene, dichlorostyrene, bromostyrene, and fluorostyrene, benzyl (meth)acrylate-based monomers such as benzyl methacrylate and benzyl acrylate, and phenyl (meth)acrylate-based monomers such as phenyl methacrylate and phenyl acrylate.

[0040] Core The core preferably contains, per 100 parts by mass of the core, 25 parts by mass or more of a structural unit derived from a styrene-based monomer, a (meth)acrylate having an aliphatic alkyl group having 4 to 24 carbon atoms, and optionally a (meth)acrylate having a hydroxy group, and a (meth)acrylate other than a (meth)acrylate having an aliphatic alkyl group having 4 to 24 carbon atoms and a (meth)acrylate having a hydroxy group. In Table 1 below, the core is formed from components other than the polymer emulsifier.

[0041] The styrene-based monomer is not particularly limited, and examples thereof include styrene, α-methylstyrene, β-methylstyrene, 2,4-dimethylstyrene, α-ethylstyrene, α-butylstyrene, 4-methoxystyrene, and vinyltoluene.

[0042] Examples of the (meth)acrylate having an aliphatic alkyl group having 4 to 24 carbon atoms and the (meth)acrylate having a hydroxy group are the same as those mentioned above in relation to the shell portion.

[0043] There are no particular limitations on the (meth)acrylates other than (meth)acrylates having an aliphatic alkyl group having 4 to 24 carbon atoms and (meth)acrylates having a hydroxy group. Examples of (meth)acrylates other than (meth)acrylates having an aliphatic alkyl group having 4 to 24 carbon atoms and (meth)acrylates having a hydroxy group include (meth)acrylates having an aliphatic hydrocarbon group such as methyl (meth)acrylate, ethyl (meth)acrylate, and propyl (meth)acrylate, (meth)acrylamide, acrylonitrile, olefin-based compounds, benzyl (meth)acrylate-based monomers such as benzyl methacrylate and benzyl acrylate, and phenyl (meth)acrylate-based monomers such as phenyl methacrylate and phenyl acrylate.

[0044] By using such a hydroxyl group-containing styrene-acrylic resin emulsion having a core-shell structure, the ink composition has good drying properties, blocking resistance, and leveling properties, and when the surface tension is reduced, poor doctoring on the printing plate and misting can be more effectively prevented even with a small amount of antifoaming agent or surfactant added.

[0045] The content of the hydroxyl-containing styrene-acrylic resin emulsion having a core-shell structure is not particularly limited. For example, the content of the hydroxyl-containing styrene-acrylic resin emulsion having a core-shell structure is preferably 15.0% by mass or more, more preferably 20.0% by mass or more, and even more preferably 22.0% by mass or more, of the total solids content of the ink composition. Furthermore, the content of the hydroxyl-containing styrene-acrylic resin emulsion having a core-shell structure is preferably 57.0% by mass or less, more preferably 50.0% by mass or less, and even more preferably 45.0% by mass or less, of the total solids content of the ink composition.

[0046] The method for producing the hydroxyl group-containing styrene-acrylic resin emulsion having a core-shell structure is not particularly limited. For example, the method for producing the hydroxyl group-containing styrene-acrylic resin emulsion having a core-shell structure can be a method for producing core-shell particles by suspension polymerization or emulsion polymerization.

[0047] Among these methods, a styrene-acrylic resin emulsion having a core-shell structure can be obtained by blending a polymerizable monomer that will form the core in the presence of the polymer emulsifier described below that will form the shell, and polymerizing the mixture by a known emulsion polymerization method. Specific examples of the polymerizable monomer include polymerizable monomers containing 25% by mass or more of a styrene-based monomer in the polymerizable monomers, and (meth)acrylates having an aliphatic alkyl group having 4 to 24 carbon atoms, such as 2-ethylhexyl (meth)acrylate and butyl (meth)acrylate, and optionally polymerizable monomers having a hydroxyl group, such as methyl methacrylate.

[0048] (polymer emulsifier) The polymer emulsifier is a copolymer of a carboxyl group-containing monomer, a (meth)acrylate having an aliphatic alkyl group having 4 to 24 carbon atoms, a (meth)acrylate having a hydroxy group, a (meth)acrylate other than a (meth)acrylate having an aliphatic alkyl group having 4 to 24 carbon atoms and a (meth)acrylate having a hydroxy group, and other radically polymerizable unsaturated monomers.

[0049] As the carboxyl group-containing monomer, the (meth)acrylate having an aliphatic alkyl group having 4 to 24 carbon atoms, the (meth)acrylate having a hydroxy group, and the (meth)acrylate other than the (meth)acrylate having an aliphatic alkyl group having 4 to 24 carbon atoms, those described above can be used.

[0050] From the viewpoint of antifoaming properties, the polymer emulsifier preferably contains butyl acrylate among the monomers constituting the polymer emulsifier.Furthermore, from the viewpoint of resolubility, leveling properties, etc., the polymer emulsifier preferably contains a (meth)acrylic acid ester compound having a hydroxyalkyl group.

[0051] It is preferable to use a carboxyl group-containing monomer for the polymer emulsifier so that the theoretical acid value is 40 to 120 mgKOH / g. By having the theoretical acid value within the above range, the stability of the hydroxyl group-containing styrene-acrylic emulsion is easily maintained, and the water resistance of the hydroxyl group-containing styrene-acrylic emulsion is easily maintained. Furthermore, the weight-average molecular weight of the polymer emulsifier is preferably in the range of 3,000 to 25,000. By having the weight-average molecular weight of the polymer emulsifier within the above range, the polymer emulsifier maintains its performance while exhibiting excellent solubility for the copolymer.

[0052] The method for producing the polymer emulsifier is not particularly limited. For example, the polymer emulsifier can be prepared by polymerizing a mixture of the above-mentioned carboxyl group-containing monomer with the above-mentioned (meth)acrylate having an aliphatic alkyl group having 4 to 24 carbon atoms, a (meth)acrylate having a hydroxyl group, and a (meth)acrylate other than the above-mentioned (meth)acrylate having an aliphatic alkyl group having 4 to 24 carbon atoms and the (meth)acrylate having a hydroxyl group, using a known method to obtain a polymer having a weight-average molecular weight of 3,000 to 25,000, and then neutralizing the polymer with a basic compound. The basic compound used for neutralization is not particularly limited. For example, basic compounds used for neutralization include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and organic basic compounds such as triethylamine, monoethanolamine, dimethylethanolamine, triethanolamine, and triethylenediamine. These may be used in combination.

[0053] (Hyperbranched polyether wetting agent) The ink composition of this embodiment contains a hyperbranched polyether wetting agent to improve leveling properties (overprintability).

[0054] The hyperbranched polyether wetting agent is not particularly limited. For example, the hyperbranched polyether wetting agent is a hyperbranched polymer having a polyether skeleton. The hyperbranched polyether wetting agent is a wetting agent having a multi-branched structure (star polymer) and is silicone-free.

[0055] Hyperbranched polyether wetting agents can be synthesized by polymerizing monomers having polymerizable functional groups such as tetrahydrofuranyl groups, epoxy groups, oxetanyl groups, and other ring-opening cyclic ethers such as anhydrides, and hydroxyl groups that can polymerize by forming ether bonds, etc. Depending on the monomers used, hyperbranched polyether wetting agents can also be synthesized by addition polymerization such as condensation polymerization, step-growth polymerization such as ring-opening polymerization, cyclopolymerization, isomerization polymerization (hydrogen transfer polymerization), elimination polymerization, or a polymerization reaction that combines two or more of these polymerizations.

[0056] In this embodiment, the polymerizable functional group in the hyperbranched polyether wetting agent preferably includes a tetrahydrofuranyl group, an epoxy group, or an oxetanyl group, and more preferably includes a tetrahydrofuranyl group or an epoxy group.

[0057] The hyperbranched polyether wetting agent preferably has a repeating unit represented by any one of the following general formulas (I) to (III).

[0058] [ka]

[0059] The hyperbranched polyether wetting agent having the repeating unit represented by general formula (I) is hyperbranched poly(glycidol), which can be synthesized, for example, by a combination of ring-opening polymerization and polycondensation of glycidol (2,3-epoxy-1-propanol).

[0060] The hyperbranched polyether wetting agent having the repeating unit represented by general formula (II) is a hyperbranched poly(tetritol). Hyperbranched poly(tetritol) can be synthesized, for example, by a combination of polycondensation of tetritol (1,2,3,4-tetrahydroxybutane) and ring-opening polymerization and polycondensation of 2,3-anhydrotetritol or 1,4-anhydrotetritol.

[0061] The hyperbranched polyether wetting agent having the repeating unit represented by general formula (III) is hyperbranched poly(3-ethyl-3-(hydroxymethyloxetane)). Hyperbranched poly(3-ethyl-3-(hydroxymethyloxetane)) can be synthesized, for example, by a combination of ring-opening polymerization and polycondensation of 3-ethyl-3-(hydroxymethyloxetane).

[0062] The average degree of branching in a hyperbranched polymer is the number-average ratio of branch groups per molecule. That is, the average degree of branching in a hyperbranched polymer is the ratio of "terminal groups + branch groups" to "the total number of terminal groups, branch groups, and linear groups," and is defined in the literature as the degree of branching (DB). Ideal dendrons and dendrimers have a degree of branching of 1, and ideal linear polymers have a degree of branching of 0. The degree of branching is defined in Hawker, CJ; Lee, R.; Frechet, JMJ, J. Am. Chem. Soc., 1991, Vol. 113, p. 4583. Specific examples of hyperbranched polyether wetting agents include Hydropalat WE 3322 and 3323 (manufactured by BASF; Hydropalat is a registered trademark of BASF).

[0063] The branching degree of the hyperbranched polyether wetting agent is not particularly limited. For example, the branching degree of the hyperbranched polyether wetting agent is preferably 0.03 or more. Furthermore, the branching degree of the hyperbranched polyether wetting agent is preferably less than 1.5. If the content of the hyperbranched polyether wetting agent is less than 0.03% by mass, the leveling properties (overprinting suitability) of the ink composition tend to deteriorate. On the other hand, if the content of the hyperbranched polyether wetting agent is more than 1.5% by mass, the blocking resistance of the ink composition tends to deteriorate.

[0064] (Silicone leveling agent) The ink composition of this embodiment preferably contains a silicone-based leveling agent to further improve leveling properties (suitability for overprinting).

[0065] The content of the silicone leveling agent is not particularly limited. For example, the content of the silicone leveling agent in the ink composition is preferably 0.1 to 0.3 mass %. When the content of the silicone leveling agent is within the above range, the ink composition has good leveling properties and is less likely to develop pinholes.

[0066] (rosin-based emulsion) The ink composition of this embodiment preferably contains a rosin-based emulsion in order to reduce carbon dioxide emissions (be carbon neutral) by using raw materials derived from plants and animals rather than from fossil fuels.

[0067] The acid value of the rosin-based emulsion is preferably 0 to 350 mgKOH / g. Rosin-based resin emulsions with an acid value of 0 to 350 mgKOH / g are prepared by dispersing rosin or a rosin derivative such as rosin ester, obtained by extracting plants, in water as fine particles in the presence of a low-molecular-weight emulsifier. Specific examples of rosin-based resin emulsions with an acid value of 0 to 350 mgKOH / g include Hariestar SK218NS, SK370N, SK385NS, and SK501NS manufactured by Harima Chemicals, Inc.; Snowpack XW-2442, XW-2551, XW-2561, XW-2582, SE780G, and 100G manufactured by LAWTER; and Superester NS-121, NS-100H, and E-865NT manufactured by Arakawa Chemical Industries, Ltd.

[0068] When a rosin-based emulsion is contained, the solid content of the rosin-based resin emulsion having an acid value of 0 to 350 mg KOH / g is preferably 1.0 mass% or more, more preferably 5.0 mass% or more, and even more preferably 10.0 mass% or more, of the total solid content of the ink composition. The solid content of the rosin-based resin emulsion having an acid value of 0 to 350 mg KOH / g is preferably 30.0 mass% or less, of the total solid content of the ink composition. Note that the carbon-neutral raw material component refers to a raw material component derived from a plant material.

[0069] (pigment dispersion resin) The pigment dispersing resin preferably contains an alkali-soluble water-soluble resin, which provides the ink composition with better colorant dispersibility, ink storage stability, and resolubility.

[0070] Alkali-soluble water-soluble resin The alkali-soluble water-soluble resin is not particularly limited, and examples thereof include resins obtained by polymerizing a monomer having an unsaturated double bond, which is used in ordinary aqueous gravure printing ink compositions, and resins obtained by reaction between functional groups.

[0071] Specifically, suitable alkali-soluble water-soluble resins include various binder resins such as water-soluble acrylic resins copolymerized with acrylic acid, methacrylic acid, alkyl esters thereof, styrene, or the like as the main monomer component, water-soluble styrene-acrylic resins, water-soluble styrene-maleic acid resins, water-soluble styrene-acrylic-maleic acid resins, water-soluble polyurethane resins, and water-soluble polyester resins.

[0072] These alkali-soluble water-soluble resins are usually dissolved in water in the presence of a basic compound and used as a water-soluble resin varnish. The basic compound used to dissolve the alkali-soluble water-soluble resin in water is ammonia, an organic amine, an alkali metal hydroxide, or the like. Specifically, the organic amine is an alkylamine such as diethylamine, triethylamine, or ethylenediamine, or an alkanolamine such as monoethanolamine, ethylethanolamine, diethylethanolamine, diethanolamine, or triethanolamine. The alkali metal hydroxide is sodium hydroxide, potassium hydroxide, or the like. Among these, the basic compound is preferably one that is easily volatilized at room temperature or with slight heating in order to improve drying properties.

[0073] The content of the alkali-soluble water-soluble resin relative to the pigment is preferably 20 parts by mass or more in terms of solid content per 100 parts by mass of the pigment. Furthermore, the content of the alkali-soluble water-soluble resin relative to the pigment is preferably 1,000 parts by mass or less, more preferably 500 parts by mass or less, in terms of solid content per 100 parts by mass of the pigment. By ensuring that the content of the alkali-soluble water-soluble resin relative to the pigment is within the above range, the ink composition exhibits excellent colorant dispersibility, ink storage stability, and resolubility, and also exhibits a good balance between leveling and drying properties.

[0074] The pigment dispersing resin preferably contains an (ethylene oxide / propylene oxide) block polymer, which provides the ink composition with better colorant dispersibility, ink storage stability, and resolubility.

[0075] (Ethylene oxide / propylene oxide) block polymer (Ethylene oxide / propylene oxide) block polymers contain two or more blocks, each of which may be composed of polyethylene oxide or propylene oxide.

[0076] The (ethylene oxide / propylene oxide) block polymer can be synthesized by known methods. For example, the (ethylene oxide / propylene oxide) block polymer can be formed by reacting a polyethylene oxide polymer with propylene oxide to form a poly(propylene oxide / ethylene oxide / propylene oxide) block polymer. Alternatively, the (ethylene oxide / propylene oxide) block polymer can be formed by reacting a polypropylene oxide polymer with ethylene oxide to form a poly(ethylene oxide / propylene oxide / ethylene oxide) block polymer.

[0077] The weight average molecular weight of the poly(ethylene oxide / propylene oxide / ethylene oxide) block polymer is preferably 5,000 to 100,000. Specific examples of commercially available poly(ethylene oxide / propylene oxide / ethylene oxide) block polymers include the Adeka Pluronic (registered trademark) series manufactured by ADEKA.

[0078] The HLB value of poly(ethylene oxide / propylene oxide / ethylene oxide) block polymers is preferably 8 to 20 in terms of stability in solvents containing water. The HLB value is used in the field of surfactants and represents the balance between the hydrophilic and lipophilic parts of a molecule (hydrophile-lipophile balance). The HLB value can be calculated using the Griffin equation shown below (a formula based on experimental values ​​obtained from measurements of emulsification efficiency for a certain oil and the weight fraction of the hydrophilic part). [Griffin formula] HLB = (100 / 5) x hydrophilic group weight / (hydrophilic group weight + hydrophobic group weight)

[0079] The content of the (ethylene oxide / propylene oxide) block polymer is preferably more than 0 parts by mass, and more preferably 0.5 parts by mass or more, per 100 parts by mass of the pigment. Furthermore, the content of the (ethylene oxide / propylene oxide) block polymer is preferably 10 parts by mass or less, and more preferably 8 parts by mass or less, per 100 parts by mass of the pigment. By ensuring that the content of the (ethylene oxide / propylene oxide) block polymer is within the above range, the ink composition exhibits excellent colorant dispersibility, ink storage stability, and resolubility, as well as a good balance between leveling and drying properties.

[0080] The total content of the alkali-soluble water-soluble resin and the (ethylene oxide / propylene oxide) block polymer is preferably 10 to 30 parts by mass per 100 parts by mass of the pigment. When the total content of the alkali-soluble water-soluble resin and the (ethylene oxide / propylene oxide) block polymer is within the above range, the ink composition exhibits excellent colorant dispersibility, ink storage stability, and resolubility, and also exhibits a good balance between leveling and drying properties.

[0081] (Antifoaming agent) Known defoaming agents can be used as the defoaming agent. Examples of the defoaming agent include hydrophobic polydimethylsiloxane-based defoaming agents, defoaming agents combining polysiloxane containing a long-chain alkyl group or an aralkyl group with polyoxyalkylene chain-containing polysiloxane, defoaming agents mainly composed of polysilcarbenesiloxane consisting of silcarbene units and siloxane units, defoaming agents consisting of a reaction product of an alkylene oxide compound, a silicone having an alcoholic hydroxyl group, and an isocyanate compound, and defoaming agents consisting of a siloxane-glycol copolymer and polypropylene glycol.

[0082] When the ink composition of this embodiment contains 20 to 50 parts by mass of structural units derived from butyl acrylate per 100 parts by mass of the shell portion of the hydroxyl group-containing styrene-acrylic resin emulsion having a core-shell structure, the contents of antifoaming agent and surfactant can be reduced to amounts lower than those contained in ordinary inks. As a result, the ink composition can prevent poor doctoring and misting on the printing plate.

[0083] The content of the antifoaming agent in the ink composition is preferably 0.3% by mass or less, and more preferably 0.2% by mass or less.

[0084] (aqueous medium) The aqueous medium is water. Alternatively, a water-soluble organic solvent may be used as the aqueous medium as long as it does not impair the performance of the ink composition of this embodiment.

[0085] The water-soluble organic solvent is an alcohol, a polyhydric alcohol solvent, etc. Specific examples of the water-soluble organic solvent include methanol, ethanol, propanol, butanol, hexanol, octanol, decanol, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monooctyl ether, diethylene glycol, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, triethylene glycol monobutyl ether, propylene glycol, propylene glycol monoethyl ether, propylene glycol, propylene glycol monoethyl ether, propylene glycol monooctyl ether, propylene glycol monomethyl ether, ethylene glycol monoethyl ether, triethylene glycol monopropyl ether, triethylene glycol monobutyl ether, propylene glycol, propylene glycol monoethyl ether, propylene glycol monooctyl ether, propylene glycol monoethyl ether, propylene glycol monooctyl ether, propylene glycol monooctyl ether, propylene glycol monoethyl ether, propylene glycol monooctyl ether, propylene glycol monooctyl ether, propylene glycol monooctyl ether, propylene glycol monooctyl ether, propylene glycol monooctyl ether, propylene glycol monooctyl ether, propylene glycol monooctyl ether, propylene glycol monooctyl ether, propylene glycol monooctyl ether, propylene glycol monooctyl ether, ethylene ... glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol, tripropylene glycol monomethyl ether, tripropylene glycol monoethyl ether, tripropylene glycol monopropyl ether, tripropylene glycol monobutyl ether, glycerin, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 2,2,4-trimethyl-1,3-pentanediol isobutyrate, 2-ethyl-1,3-hexanediol, 1,6-hexanediol diacetate, isoamyl acetate, and the like.

[0086] From the viewpoint of drying properties and leveling properties, the aqueous medium preferably contains water and a lower alcohol having 1 to 4 carbon atoms.

[0087] There is no particular limitation on the lower alcohol having 1 to 4 carbon atoms. Examples of lower alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, and isobutanol.

[0088] The content of the lower alcohol having 1 to 4 carbon atoms in the ink composition is preferably 1 to 30 mass %. When the content of the lower alcohol having 1 to 4 carbon atoms is within the above range, the ink composition has better leveling properties, drying properties, and ink storage stability.

[0089] (wax) Wax may be added to improve the stain resistance and rub resistance of the resulting printed matter.

[0090] The type of wax is not particularly limited, but examples of wax include polyethylene wax and polytetrafluoroethylene wax.

[0091] The wax preferably has an average particle size in the range of 1.0 to 6.0 μm as measured by the Coulter Counter method (the average particle size refers to the particle size measured with #1 Microtrac UPA manufactured by Honeywell). When the average particle size is within the above range, the ink composition has excellent sliding properties, anti-blocking properties, and trapping properties.

[0092] When wax is contained, the content of the wax is not particularly limited. For example, the content of the wax is preferably 0.1 to 3.0 mass% of the total solid content of the ink composition. When the content of the wax is within the above range, the ink composition can easily obtain the effects of blending the wax, and the resulting printed matter has excellent gloss.

[0093] (Other optional ingredients) The ink composition of this embodiment may contain optional components, such as a surfactant, a wetting agent other than the hyperbranched polyether wetting agent, a pH adjuster, a viscosity adjuster, a drying adjuster, a gloss agent, and a crosslinking agent.

[0094] <Method for producing a water-based gravure printing ink composition for paper containers> The method for producing the ink composition of this embodiment is not particularly limited. For example, the ink composition can be produced by mixing a pigment, a pigment dispersion resin, and the like, stirring and kneading the mixture using a known ink production device (such as a ball mill, an attritor, or a sand mill), and then adding and mixing a hydroxyl group-containing styrene-acrylic resin emulsion having a core-shell structure, a rosin emulsion, an antifoaming agent, a wax, an aqueous solvent, and, if necessary, an alkali-soluble water-soluble resin. If dilution is required during printing, a solvent containing water can be further added to obtain the ink composition.

[0095] <Printed matter printed with aqueous gravure printing ink composition and method for producing printed matter> A printed matter according to one embodiment of the present invention is a printed matter on which the ink composition described above is printed.

[0096] The method for producing the printed matter is not particularly limited. As an example, the printed matter can be produced by printing the ink composition described above on a paper substrate such as coated paper by gravure printing.

[0097] Considering the production efficiency of printed matter, the printing speed is preferably 150 m / min or more. Furthermore, the production method of this embodiment may employ a drying step using various types of heat drying equipment after printing. The viscosity of the ink composition during printing is preferably such that the Zahn Cup No. 3 flow time is approximately 15 to 19 seconds. By having a viscosity within the above range, the ink composition has excellent leveling properties and printability.

[0098] The ink composition may also be stored in a concentrated state and diluted with a diluent before use at the time of printing.

[0099] The resulting printed matter is made of the ink composition described above. Therefore, the printed matter uses many carbon-neutral raw materials, has excellent gloss, has few white spots, and is capable of being overprinted. [Example]

[0100] The present invention will be described in more detail below with reference to examples. The present invention is not limited to these examples. Unless otherwise specified, "%" means "% by mass" and "parts" means "parts by mass."

[0101] The raw materials used, their abbreviations, and preparation methods are listed below. (polymerizable monomers, etc.) AA: acrylic acid MMA: Methyl methacrylate BA: butyl acrylate 2-EHA: 2-ethylhexyl acrylate St: styrene 2-HEMA: 2-hydroxyethyl methacrylate DMEA: Dimethylethanolamine IPA: Isopropanol

[0102] <Base ink> Base inks of each color were prepared by blending and mixing 30 parts by mass of each pigment (yellow pigment (PY3) or black pigment (PB7)), 45 parts by mass of the alkali-soluble water-soluble resin described below as a pigment dispersion resin, 1.4 parts by mass of poly(ethylene oxide / propylene oxide) block polymer (HLB value 14, MW 16000), and 23.6 parts by mass of water.

[0103] The solid content concentration of these base inks was 40.49% by mass (=30+(45×20.2%)+1.4).

[0104] (alkali-soluble water-soluble resin) 15 parts by mass of styrene, 60 parts by mass of methyl methacrylate, 10 parts by mass of lauryl methacrylate, and 15 parts by mass of acrylic acid were copolymerized by a conventional polymerization method to obtain a copolymer with an acid value of 80 mgKOH / g and a weight-average molecular weight of 38,000. This copolymer resin was neutralized with dimethylethanolamine (DMEA) water to obtain an alkali-soluble water-soluble resin with a solids concentration of 20.2%.

[0105] (Hydroxyl-containing styrene-acrylic resin emulsion with core-shell structure) According to the formulations shown in Table 1 below, hydroxyl group-containing styrene-acrylic resin emulsions A to D having a core-shell structure were obtained.

[0106] [Table 1]

[0107] Specifically, to synthesize a hydroxyl-containing styrene-acrylic resin emulsion A having a core-shell structure, first, a polymer emulsifier A (solid content 30%), which is the base for resin particles having a core-shell structure, was synthesized so that the mass ratio of the monomers was as shown in Table 1.

[0108] Next, a core-shell structure (resin particles A having a core-shell structure) was synthesized in which polymer emulsifier A was the shell portion and a phase consisting of other monomer components was the core portion, so that the mass ratio of the monomers in Table 1 was achieved, and a hydroxyl group-containing styrene-acrylic resin emulsion A having a core-shell structure (solid content concentration 40.0 mass%) containing this was obtained.

[0109] Similarly, polymer emulsifiers B to D were used to synthesize resin particles B to D having a core-shell structure, and hydroxyl-containing styrene-acrylic resin emulsions B to D having a core-shell structure with a solid content of 40.0 mass % were obtained, respectively.

[0110] <Hyperbranched polyether wetting agent> Hyperbranched polyether wetting agent 1: Hydropalat WE 3322 (BASF) Hyperbranched polyether wetting agent 2: Hydropalat WE 3323 (BASF) <Rosin-based emulsion> Esterified rosin emulsion (solids 50% by mass, remainder water) <Wax> Polyethylene wax (Chemipearl W400 (Mitsui Chemicals, Inc.) solid content 40% by mass) <Silicone leveling agent> Product name: Dynol 960 (manufactured by Evonik) <Other> Octanediol: 2-ethyl-1,3-hexanediol, manufactured by KH Neochem Co., Ltd. Disparlon LS-430: Manufactured by Kusumoto Chemicals Co., Ltd., silicone-based propylene glycol monomethyl ether acetate Disparlon LS-460: manufactured by Kusumoto Chemicals Co., Ltd., silicone-based Disparlon LS-480: manufactured by Kusumoto Chemicals Co., Ltd., silicone-based Disparlon SEI-W01: Acrylic polymer, manufactured by Kusumoto Chemicals Co., Ltd. Disparlon SEI-1501: Acrylic polymer, manufactured by Kusumoto Chemicals Co., Ltd. Disparlon FCD-150: Manufactured by Kusumoto Chemicals Co., Ltd. BYK-3560: BYK, polyether macromer modified acrylate BYK-3565: BYK, silicone and polyether macromer modified acrylate BYK-3566: BYK, silicone and polyether macromer modified acrylate BYK-3568: BYK, silicone and polyether macromer modified acrylate BYK-Dynwet 800: BYK, alcohol alkoxylate BYK-Dynwet 810: BYK, silicone-free alcohol alkoxylate

[0111] <Examples and Comparative Examples> The raw materials were blended to the mass proportions (% by mass) shown in Tables 2 to 5 below, and mixed by stirring to obtain aqueous gravure printing ink compositions for paper containers. The ink compositions were then diluted with a 70 / 30 mixture of isopropanol and water to a Zahn Cup No. 3 viscosity of 15 to 19 seconds and a solids concentration in the aqueous gravure printing ink composition for paper containers of 15 to 30% by mass, to obtain yellow and gray aqueous gravure printing ink compositions for paper containers, respectively.

[0112] [Table 2]

[0113] [Table 3]

[0114] [Table 4]

[0115] [Table 5]

[0116] <Production of printed matter and evaluation of printed matter> 100 parts by mass of each aqueous gravure printing ink composition for paper containers (gray ink and yellow ink) of the Examples and Comparative Examples in Tables 1 to 5 was diluted with 50 parts by mass of a mixed solvent (isopropyl alcohol / water = 70 / 30), and the resulting ink composition was adjusted to a viscosity of approximately 17 seconds using a Zahn Cup No. 3 at 25°C. Printing was carried out using each aqueous gravure printing ink composition for paper containers (gray ink and yellow ink) under the following conditions to obtain each printed matter. Each printed matter was evaluated for printability (drying speed, leveling (polka dots), leveling (suitability for overprinting), pinholes, resolubility, and tone reproducibility) according to the following evaluation methods and criteria. The results are shown in Tables 6 and 7.

[0117] (Printing conditions) Leveling properties (polka dots) For the leveling (polka dots), in the case of single-color printing, a gray ink (Table 4, Table 5) with a viscosity of 17 seconds was printed under the conditions below, and in the case of overprinting, a yellow ink (Table 2, Table 3) with a viscosity of 17 seconds was printed, and then the gray ink with a viscosity of 17 seconds was printed. The printed matter was then visually evaluated for ring-shaped leveling defects. <Evaluation criteria> 5: Ink was applied evenly across the entire coating. 3: A small amount of unevenness in shade occurred throughout the entire coating film. 1: There was a lot of unevenness in the shade throughout the entire coating. Pinhole For pinholes, gray ink (Tables 4 and 5) with a viscosity of 17 seconds was printed under the conditions below, and the occurrence of pinholes (cissing) on ​​the printed matter was visually evaluated. <Evaluation criteria> 5: No pinholes were generated. 3: A small number of pinholes occurred. 1: Many pinholes occurred. Paper: Coated paper (CRC230, manufactured by Rengo Co., Ltd.) Printing machine: Toshiba gravure printing machine Printing plate for printing water-based gravure printing ink composition for paper containers :Helio 175 line / inch (Pattern: Gradation plate with halftone dot density of 5 to 100%) Printing speed: 150~200m / min Drying conditions: 80℃・80cm 3 / min Printing pressure: 2.2t Leveling ability (evaluated by overprinting suitability and ink spreading) Using a bar coater φ0.10, underprinting yellow ink (Table 2, Table 3) with a viscosity of 17 seconds was applied to coated paper, and the drying state was adjusted by using a dryer or not. Overprinting gray ink (Table 4, Table 5) with a viscosity of 17 seconds was printed on top of the dry and wet underprinting yellow ink under the conditions below, and leveling properties (ink adhesion and spreading) were evaluated. <Evaluation criteria> 5: The overprint ink film was applied evenly. 3: There was a small amount of unevenness in the overprint ink coating and poor wetting and spreading of the halftone dots. 1: There were many uneven spots on the overprinting ink film and poor wetting and spreading of the halftone dots. Paper: Coated paper (CRC230, manufactured by Rengo Co., Ltd.) Printing machine: Toshiba gravure printing machine Printing plate for printing water-based gravure printing ink composition for paper containers :Helio 200 line / inch (Design: Gradient version with 10 levels of gradation) Printing speed: 50m / min Drying conditions: 80℃・80cm 3 / min Printing pressure: 2.2t Tone reproducibility The gray ink (Tables 4 and 5) was adjusted to a viscosity of 17 seconds, and printed under the following conditions. The spread of dots in the halftone and highlight areas of the printed matter was visually evaluated. <Evaluation criteria> 5: The dots were sufficiently spread out. 3: The spread of the halftone dots was slightly insufficient. 1: The dots were not sufficiently spread. Paper: Coated paper (CRC230, manufactured by Rengo Co., Ltd.) Printing machine: Toshiba gravure printing machine Printing plate for printing water-based gravure printing ink composition for paper containers :Helio 200 line / inch (Design: Gradient version with 10 levels of gradation) Printing speed: 50m / min Drying conditions: 80℃・80cm3 / min Printing pressure: 2.2t ·Drying The gray ink (Tables 4 and 5) was adjusted to a viscosity of 17 seconds, and printing and coating were carried out on a printing press at different printing speeds and air volumes. When the guide roll (printed surface, coated surface) vibrated, the degree to which the ink adhered to and stained the guide roll was visually inspected and evaluated according to the following criteria. <Evaluation criteria> 5: No adhesion to the guide roll. 3: The amount of adhesion to the guide roll was small. 1: There was a large amount of adhesion to the guide roll. Paper: Coated paper (CRC230, manufactured by Rengo Co., Ltd.) Printing machine: Toshiba gravure printing machine Printing plate for printing water-based gravure printing ink composition for paper containers :Helio 200 line / inch (Design: Gradient version with 10 levels of gradation) Printing speed: 50m / min Drying conditions: 80℃・80cm 3 / min Printing pressure: 2.2t -Prevents white spots Printing was carried out for 30 seconds using a printing press, and the occurrence of white spots was visually observed and evaluated according to the following evaluation criteria. <Evaluation criteria> 5: No white spots were observed throughout the entire coating film. 3: A small amount of white spots occurred throughout the entire coating film. 1: Many white spots occurred throughout the entire coating. Paper: Coated paper (CRC230, manufactured by Rengo Co., Ltd.) Printing machine: Toshiba gravure printing machine Printing plate for printing water-based gravure printing ink composition for paper containers :Helio 200 line / inch (Design: Gradient version with 10 levels of gradation) Printing speed: 80m / min Drying conditions: 80℃・80cm 3 / min Printing pressure: 2.2t ·Resolubility A gray ink (Table 4, Table 5) with a viscosity of 17 seconds was applied to an OPP film using a bar coater with a diameter of 0.10 mm, and the film was immersed in a solution of isopropyl alcohol and water in a ratio of 3:7. Dissolution of the ink composition for gravure printing on paper containers during the drying process was evaluated visually. <Evaluation criteria> 5: After application, the color dissolved within 1 minute. 3: After application, the color began to dissolve within 3 minutes but not more than 1 minute. 1: After application, the paint began to dissolve within 5 minutes but more than 3 minutes.

[0118] [Table 6]

[0119] [Table 7]

[0120] As shown in Tables 6 and 7, the ink compositions of Examples 1 to 9 of the present invention used many raw materials that can be carbon neutral, and were excellent in drying properties, prevention of white voids, resolubility, and leveling properties (polka dots, overprinting suitability). Similarly, the ink compositions of Examples 10 to 18 were also confirmed to use many raw materials that can be carbon neutral, and were excellent in drying properties, prevention of white voids, resolubility, and leveling properties (polka dots, overprinting suitability).

Claims

1. The ink contains a pigment, a hydroxyl group-containing styrene-acrylic resin emulsion, a pigment dispersion resin, a hyperbranched polyether wetting agent, and an aqueous medium; the content of the hyperbranched polyether wetting agent in the aqueous gravure printing ink composition for paper containers is 0.03 to 1.5% by mass, The pigment dispersing resin comprises an ethylene oxide / propylene oxide block polymer.

2. The hydroxyl group-containing styrene-acrylic resin emulsion has a core-shell structure, 2. The aqueous gravure printing ink composition for paper containers according to claim 1, wherein the core-shell structure has, in at least one of the shell portion and the core portion, a structural unit derived from a (meth)acrylate having an aliphatic alkyl group having 4 to 24 carbon atoms and a structural unit derived from a (meth)acrylate having a hydroxy group.

3. 3. The water-based gravure printing ink composition for paper containers according to claim 1, further comprising a silicone-based leveling agent.

4. 3. The aqueous gravure printing ink composition for paper containers according to claim 1, which contains a rosin emulsion.

5. 3. The aqueous gravure printing ink composition for paper containers according to claim 2, wherein the (meth)acrylate having a hydroxy group is 2-hydroxyethyl (meth)acrylate.

6. 3. The water-based gravure printing ink composition for paper containers according to claim 1, wherein the pigment dispersing resin comprises an alkali-soluble water-soluble resin.

7. A printed matter printed with the aqueous gravure printing ink composition for paper containers according to claim 1 or 2.

Images