Water-based resin composition for gravure printing

Abstract

To provide: an aqueous resin composition for gravure printing, having excellent dispersion stability of an aqueous resin composition or an ink, and excellent film formability and water resistance when used as a gravure printing ink; and a gravure printing ink.SOLUTION: Provided is an aqueous resin composition for gravure printing, comprising resin (A) and resin (B), where an acid value of a nonvolatile content of the aqueous resin composition is less than 50 mg KOH / g and a glass transition temperature of the nonvolatile content of the aqueous resin composition is 50°C or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an aqueous resin composition for gravure printing. And it relates to a gravure printing ink containing the aqueous resin composition. The aqueous resin composition of the present invention can be suitably used as a gravure printing ink.

Background Art

[0002] In recent years, for the purpose of air pollution prevention and improvement of the printing work environment, the aqueous conversion of printing inks has been demanded. By replacing most of the volatile components in the ink from organic solvents to water, the amount of organic solvents released into the external environment can be significantly reduced. In order to achieve the above object, the aqueous conversion of each component contained in the ink is required. In particular, the binder component is important for expressing important physical properties such as pigment dispersibility, rheological properties, and coating film performance. As the binder component, the use of aqueous solutions or aqueous dispersions of polymers such as olefin resins, chlorinated olefin resins, acrylic resins, urethane resins, and polyester resins has been widely studied. For example, Patent Document 1 discloses a core-shell type resin fine particle dispersion (B) with an acid value of 50 to 90 mgKOH / g obtained by polymerizing an ethylenically unsaturated monomer (b) in an aqueous medium in the presence of a water-soluble resin (A) obtained by polymerizing an ethylenically unsaturated monomer (a), and a resin fine particle dispersion (D) with an acid value of 0 to 30 mgKOH / g obtained by polymerizing an ethylenically unsaturated monomer (d) in an aqueous medium in the presence of a surfactant (C). An aqueous ink binder resin composition characterized by containing them is described, and it is described that the acid value of the water-soluble resin (A) is preferably 100 to 300 mgKOH / g from the viewpoints of the dispersion stability of the resin particle dispersion and the physical properties of the coating film.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] However, when using resin particles with a high acid value, such as those in Patent Document 1, there was a problem in that the durability of the coating film decreased. The object of the present invention is to provide an aqueous resin composition and a gravure printing ink that exhibit excellent dispersion stability, as well as excellent film-forming properties and coating durability when used as a gravure printing ink. [Means for solving the problem]

[0005] In view of the above-mentioned problems, the inventors conducted research and found that an aqueous resin composition for gravure printing containing resin (A) and resin (B), wherein the acid value in the nonvolatile content of the aqueous resin composition is less than 50 mgKOH / g, and the glass transition temperature in the nonvolatile content of the aqueous resin composition is 50°C or lower, exhibits excellent dispersion stability of the aqueous resin composition or ink, as well as excellent film-forming properties and water resistance when used as a gravure printing ink, thus completing the present invention. [Effects of the Invention]

[0006] The present invention provides an aqueous resin composition and a gravure printing ink that exhibit excellent dispersion stability, as well as excellent film-forming properties and water resistance when used as a gravure printing ink. [Modes for carrying out the invention]

[0007] The aqueous resin composition for gravure printing of this disclosure is an aqueous resin composition for gravure printing comprising resin (A) and resin (B), characterized in that the acid value in the nonvolatile content of the aqueous resin composition is less than 50 mgKOH / g, and the glass transition temperature in the nonvolatile content of the aqueous resin composition is 30°C or lower. In this specification, "resin" is a broader concept than "polymer." A resin may contain one or more polymers. A "composition (resin composition)" may contain materials other than polymers, such as additives.

[0008] <Resin (A)> Examples of the resin (A) in this disclosure include polyester resins, polyurethane resins, epoxy resins, vinyl resins, and modified resins thereof. These may be present individually or in combination of two or more types.

[0009] Examples of the polyester resin include polybasic acids (e.g., compounds having 2 to 4 carboxyl groups or methyl carboxylate groups in one molecule, such as (anhydride) phthalic acid, isophthalic acid, terephthalic acid, (anhydride) maleic acid, (anhydride) pyromellitic acid, (anhydride) trimellitic acid, (anhydride) succinic acid, sebatic acid, azelaic acid, dodecanedicarboxylic acid, dimethyl isophthalate, dimethyl terephthalate, sodium 5-sulfoizophthalate, etc.) and polyhydric alcohols (e.g., ethylene glycol, propylene glycol, neopentyl glycol) Examples include resins obtained by esterifying or transesterifying alcohols (such as 1,6-hexanediol, diethylene glycol, triethylene glycol, trimethylolpropane, pentaerythritol, glycerin, tricyclodecanedimethanol, and dimethylolpropionic acid, which have 2 to 6 hydroxyl groups in one molecule) with monobasic acids (for example, fatty acids such as castor oil fatty acid, soybean oil fatty acid, tall oil fatty acid, linseed oil fatty acid, or benzoic acid) or oils and fats, in such a way that carboxyl groups necessary for aqueous conversion remain.

[0010] Examples of the polyurethane resin include reaction products of dimethylolpropionic acid and, if necessary, polyols (e.g., alkoxy polyalkylene glycols such as ethylene glycol, propylene glycol, methoxypolymethylene ether glycol, methoxypolyethylene ether glycol, ethoxypolyethylene ether glycol, ethoxypolybutylene ether glycol, etc.) and polyisocyanate compounds (e.g., aliphatic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate; alicyclic diisocyanates such as 4,4'-methylenebis(cyclohexyl isocyanate), isophorone diisocyanate; aromatic diisocyanates such as xylylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, polyphenylmethane diisocyanate; their isocyanurate and biuret forms; etc.).

[0011] Examples of the epoxy resin include a single radical polymer of a radical polymerizable monomer containing an epoxy group (e.g., 3,4-epoxycyclohexylmethyl(meth)acrylate, glycidyl(meth)acrylate, etc.), a copolymer of the monomer and other radical polymerizable monomers (e.g., alkyl or cycloalkyl esters of (meth)acrylic acid having 1 to 24 carbon atoms, styrene, etc.), a trifunctional alicyclic epoxy resin (commercial products include, for example, "Epolide GT300" manufactured by Daicel Chemical Industries, Ltd., "EHPE" manufactured by Daicel Chemical Industries, Ltd., etc.), and a tetrafunctional alicyclic epoxy resin. Examples include epoxy resins (commercially available, for example, "Epolid GT400" manufactured by Daicel Chemical Industries, Ltd.), bisphenol-type epoxy resins, novolac-type epoxy resins, ε-caprolactam-modified bisphenol-type epoxy resins, polyvinylcyclohexene diepoxide, and other conventionally known epoxy resins having at least one epoxy group per molecule, which are modified with polycarboxylic acids such as polycarboxylic acid resins (e.g., acrylic resins, polyester resins, etc.) or polycarboxylic acid compounds (e.g., adipic acid, sebacic acid, phthalic acid, etc.).

[0012] The vinyl resins of this disclosure include embodiments that include polymers obtained by polymerizing monomer components consisting of a carboxyl group-containing vinyl monomer and, if necessary, other unsaturated monomers.

[0013] The carboxyl group-containing vinyl monomers of this disclosure can be any unsaturated compound containing at least one carboxyl group (including anhydrous carboxyl groups) and one radically polymerizable unsaturated group in one molecule. Specific examples include (meth)acrylic acid, maleic anhydride, fumaric acid, itaconic acid, and the like.

[0014] Other unsaturated monomers in this disclosure are unsaturated monomers other than the carboxyl group-containing vinyl monomers, and are non-functional unsaturated compounds that do not substantially react with the carboxyl group. Examples include (meth)acrylic acid ester monomers, aromatic vinyl monomers, (meth)acrylamide, vinyl ether monomers, vinyl chloride, vinylidene chloride, vinylidene fluoride, vinyl acetate, N-vinylpyrrolidone, acrylonitrile, and the like. Examples of (meth)acrylic acid monomers in this disclosure include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, n-octyl (meth)acrylate, lauryl (meth)acrylate, dodecyl (meth)acrylate, stearyl (meth)acrylate, 2-ethylhexyl carbitol (meth)acrylate, isobornyl (meth)acrylate, methoxybutyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxybutyl (meth)acrylate, trimethylolpropanetripoxy (meth)acrylate, benzyl (meth)acrylate, perfluorobutyl ethyl (meth)acrylate, perfluoroisononyl ethyl (meth)acrylate, and perfluorooctyl ethyl (meth)acrylate.

[0015] The aromatic vinyl monomers of this disclosure are not particularly limited as long as they are compounds in which a vinyl group is bonded to an aromatic ring. Examples include styrene monomers such as styrene, vinyltoluene, and methoxystyrene; polycyclic aromatic hydrocarbon ring vinyl monomers such as 2-vinylnaphthalene; and aromatic heterocyclic vinyl monomers such as N-vinylcarbazole, 2-vinylpyridine, vinylimidazole, and vinylthiophene. They may also include monomers in which the vinyl group has substituents other than aromatic rings, such as α-methylstyrene, α-hydroxymethylstyrene, and α-hydroxyethylstyrene. Among these, styrene monomers are preferred. Styrene monomers include not only styrene but also styrene derivatives in which any substituent is bonded to the polymerizable double bond carbon or benzene ring of styrene. Examples of substituents include alkyl groups, alkoxy groups, hydroxyl groups, halogen groups, amino groups, nitro groups, sulfo groups, etc. The alkyl and alkoxy groups bonded to styrene preferably have 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms, and at least some of the hydrogen atoms of the alkyl and alkoxy groups bonded to styrene may be substituted with hydroxyl or halogen groups. Furthermore, from the viewpoint of reducing the coloration of the resin composition, it is preferable that the styrene monomer does not have an amino group.

[0016] Examples of (meth)acrylamides in this disclosure include (meth)acrylamide, N-monomethyl(meth)acrylamide, N-monoethyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, and (meth)acryloylmorpholine.

[0017] Examples of vinyl ether monomers in this disclosure include methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, t-butyl vinyl ether, n-octyl vinyl ether, 2-ethylhexyl vinyl ether, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, 1,4-cyclohexanedimethanol monovinyl ether, cyclohexyl vinyl ether, diethylene glycol monovinyl ether, and the like.

[0018] The modification of resins in this disclosure is not particularly limited, but examples include saponification, in which a base is reacted with at least some of the acetoxy groups of the resin, and grafting, in which another polymerizable monomer is polymerized or a high molecular weight agent is reacted with at least some of the side chains or terminal functional groups of the resin. The disclosure also includes resins obtained by polymerizing in which at least some of the monomers are replaced with prepolymers or macromonomers. The prepolymers and macromonomers refer to polymerizable monomers having a relatively large molecular weight obtained by reacting monomers with a high molecular weight agent or the like in advance.

[0019] In this specification, the expression "(meth)acrylic" means "acrylic and / or methacrylic," the expression "(meth)acrylate" means "acrylate and / or methacrylate," and the expression "(meth)acrylic acid" means acrylic acid and / or meacrylic acid. In this specification, a monomer-derived structural unit means a structural unit obtained by polymerizing monomers, and a (meth)acrylic acid and / or (meth)acrylic acid ester-derived structural unit means a structural unit obtained by polymerizing (meth)acrylic acid and / or (meth)acrylic acid esters.

[0020] As the resin (A) of the present disclosure, a polyester resin, a polyurethane resin, or a vinyl resin is preferable, a vinyl resin is more preferable, and it is further preferable to contain a carboxy group-containing vinyl polymer.

[0021] The content of the structural unit derived from the carboxy group-containing vinyl monomer in the resin (A) of the present disclosure is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and further preferably 5 parts by mass or more per 100 parts by mass of the resin (A) to ensure sufficient water solubility and stably disperse the aqueous resin composition. To prevent significant thickening of the aqueous resin composition and ensure the printing suitability and storage stability of the ink using the aqueous resin composition, it is preferably 25 parts by mass or less, more preferably 20 parts by mass or less, and further preferably 15 parts by mass or less.

[0022] When the resin (A) of the present disclosure has a structural unit derived from (meth)acrylic acid, the content of the structural unit derived from (meth)acrylic acid is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and further preferably 5 parts by mass or more per 100 parts by mass of the resin (A) to ensure sufficient water solubility and stably disperse the aqueous resin composition. To prevent significant thickening of the aqueous resin composition and ensure the printing suitability and storage stability of the ink using the aqueous resin composition, it is preferably 25 parts by mass or less, more preferably 20 parts by mass or less, and further preferably 15 parts by mass or less.

[0023] When the resin (A) of the present disclosure has a structural unit derived from (meth)acrylate, it is preferable to have a structural unit derived from (meth)acrylate having a substituent with 1 to 10 carbon atoms, more preferably a structural unit derived from (meth)acrylate having a substituent with 1 to 8 carbon atoms, and further preferably a structural unit derived from (meth)acrylate having a substituent with 1 to 6 carbon atoms.

[0024] If the resin (A) of the present disclosure has structural units derived from (meth)acrylic acid ester, examples include structural units derived from (meth)acrylic acid ester having a linear alkyl group, structural units derived from (meth)acrylic acid ester having a branched alkyl group, and structural units derived from (meth)acrylic acid ester having a cyclic alkyl group, with structural units derived from (meth)acrylic acid ester having a linear alkyl group and structural units derived from (meth)acrylic acid ester having a branched alkyl group being preferred.

[0025] Examples of linear alkyl group-containing (meth)acrylic acid esters of this disclosure include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, behenyl (meth)acrylate, methoxyethyl (meth)acrylate, and ethyl (meth)acrylate. Examples include carbitol, ethoxypolyethylene glycol (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, aminoethyl (meth)acrylate, chloroethyl (meth)acrylate, trifluoroethyl (meth)acrylate, and heptadecafluorooctylethyl (meth)acrylate, with methyl (meth)acrylate, ethyl (meth)acrylate, and hydroxyethyl (meth)acrylate being preferred, and methyl (meth)acrylate and ethyl (meth)acrylate being more preferred.

[0026] Examples of (meth)acrylic acid esters having a branched alkyl group in this disclosure include isopropyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, neopentyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)acrylate, isostearyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, methoxytripropylene glycol (meth)acrylate, and hexafluoropropyl (meth)acrylate, with isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate being preferred, and 2-ethylhexyl (meth)acrylate being more preferred.

[0027] Examples of (meth)acrylic acid esters having a cyclic alkyl group in this disclosure include glycidyl (meth)acrylate, methyl (3-ethyloxetan-3-yl)methyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, and phenoxyethyl (meth)acrylate, with glycidyl (meth)acrylate and tetrahydrofurfuryl (meth)acrylate being preferred.

[0028] The content of structural units derived from (meth)acrylic acid esters per 100 parts by mass of resin (A) of the present disclosure is preferably 75 parts by mass or more, more preferably 80 parts by mass or more, and even more preferably 85 parts by mass or more.

[0029] The content of structural units derived from (meth)acrylic acid ester having a linear alkyl group per 100 parts by mass of resin (A) of the present disclosure is preferably 50 parts by mass or more, more preferably 60 parts by mass or more, even more preferably 70 parts by mass or more, preferably 90 parts by mass or less, more preferably 85 parts by mass or less, and even more preferably 80 parts by mass or less.

[0030] The content of structural units derived from (meth)acrylic acid ester having a branched alkyl group per 100 parts by mass of resin (A) of the present disclosure is preferably 0 parts by mass or more, more preferably 2 parts by mass or more, even more preferably 5 parts by mass or more, preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less.

[0031] The mass ratio of structural units derived from (meth)acrylic acid ester having a linear alkyl group to structural units derived from (meth)acrylic acid ester having a branched alkyl group in resin (A) of the present disclosure (mass of structural units derived from (meth)acrylic acid ester having a linear alkyl group / mass of structural units derived from (meth)acrylic acid ester having a branched alkyl group) is preferably 50 / 50 to 100 / 0, more preferably 60 / 40 to 100 / 0, and even more preferably 70 / 30 to 100 / 0.

[0032] As for the resin (A) of this disclosure, the content of structural units derived from aromatic vinyl monomers is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less per 100 parts by mass of resin (A), from the viewpoint of substrate adhesion and coating film durability when used as a gravure printing ink.

[0033] The resin (A) in this disclosure preferably has monomer-derived structural units with an octanol / water partition coefficient of 2.5 or less in order to improve the hydrophilicity of resin (A) and ensure the dispersion stability of the aqueous resin composition. The octanol / water partition coefficient in this disclosure is the value listed in the International Chemical Safety Card (ICSC), and in the case of components for which there is no such listing, the value obtained using calculation software (Advanced Chemistry Development, Inc., product name: ACD / LogP) is used. Monomers with an octanol / water partition coefficient of 2.5 or less include, but are not limited to, (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl acrylate, isobutyl acrylate, methoxypolyethylene (meth)acrylate, methoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, acetatoxyethyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, (meth)acrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, diacetone acrylamide, maleic anhydride, (meth)acrylonitrile, N-vinylpyrrolidone, itaconic acid, vinyl acetate, vinyl benzoate, and sodium p-styrenesulfonate.

[0034] The content of monomer-derived structural units in resin (A) of this disclosure having an octanol / water partition coefficient of 2.5 or less is preferably 60 parts by mass or more, more preferably 70 parts by mass or more, and even more preferably 80 parts by mass or more, per 100 parts by mass of resin (A), from the viewpoint of dispersion stability of aqueous resin compositions and inks.

[0035] The acid value of resin (A) in this disclosure is preferably 30 mg KOH / g or more, more preferably 40 mg KOH / g or more, and even more preferably 50 mg KOH / g or more, from the viewpoint of dispersion stability of aqueous resin compositions and inks, and is preferably 200 mg KOH / g or less, more preferably 150 mg KOH / g or less, and even more preferably 100 mg KOH / g or less, from the viewpoint of suppressing thickening of aqueous resin compositions and printability and storage stability when used as an ink. The resin (A) of this disclosure is preferably an alkali-soluble resin for reasons such as imparting appropriate viscosity characteristics to the ink and making the ink easier to redissolve on the printing plate. The acid value of resin (A) in this disclosure indicates the number of milligrams of potassium hydroxide required to neutralize the acidic components contained in 1 g of resin (A). It can be calculated using dried resin (A) by a measurement method in accordance with JIS K 5601-2-1, or it can be calculated from the amount of monomers that make up resin (A) charged. The glass transition temperature of resin (A) of the present disclosure is not particularly limited, but is preferably 20°C or higher, more preferably 30°C or higher, and even more preferably 40°C or higher from the viewpoint of preventing blocking, and is preferably 80°C or lower, more preferably 70°C or lower, and even more preferably 60°C or lower from the viewpoint of film formation.

[0036] The glass transition temperature of resin (A) can be determined by differential scanning calorimetry (DSC), differential calorimetry (DTA), thermomechanical analysis (TMA), etc., or by using the glass transition temperature of the monomer homopolymer used in the monomer component used as a raw material for the polymer, using the formula: 1 / Tg = Σ(Wm / Tgm) / 100 It can also be determined based on Fox's formula, which is expressed as follows: [In the formula, Wm represents the content (mass%) of monomer m in the inner layer monomer component constituting the resin layer, and Tgm represents the glass transition temperature (absolute temperature: K) of the homopolymer of monomer m]. For monomers whose glass transition temperature is unknown, such as special monomers and polyfunctional monomers, if the total amount of monomers with unknown glass transition temperatures in the monomer component is 10 mass% or less, the glass transition temperature calculated using only monomers with known glass transition temperatures can be used as a substitute. If the total amount of monomers with unknown glass transition temperatures in the monomer component exceeds 10 mass%, the glass transition temperature of the resin can be determined by differential scanning calorimetry (DSC), differential calorimetry (DTA), thermomechanical analysis (TMA), etc.

[0037] The weight-average molecular weight of resin (A) in this disclosure is preferably 1,000 or more, more preferably 3,000 or more, and even more preferably 5,000 or more, from the viewpoint of the dispersion stability of the pigment in the ink containing resin (A). To prevent significant thickening of the ink and the resulting deterioration of the storage stability of the ink, it is preferably 100,000 or less, more preferably 50,000 or less, and even more preferably 30,000 or less. In this specification, weight-average molecular weight refers to the weight-average molecular weight (polystyrene equivalent) measured by gel permeation chromatography [Tosoh Corporation, catalog number: HLC-8320GPC, column: two TSKgel SuperMultiporeHZ-M columns connected in series, effluent: THF].

[0038] <Resin (B)> Examples of the resin (B) in this disclosure include polyvinyl acetate polymers, ethylene-vinyl acetate copolymers, vinyl acetate-(meth)acrylic acid ester copolymers, (meth)acrylic acid ester copolymers, styrene-butadiene copolymers, styrene-(meth)acrylic acid ester copolymers, maleated polybutadiene polymers, polyvinyl chloride polymers, vinyl chloride-vinylidene chloride copolymers, synthetic rubber latex, polyester polymers, silicone polymers, acrylic silicone polymers, fluoropolymers, urethane polymers, epoxy polymers, etc., and it is preferable to include (meth)acrylic acid ester copolymers from the viewpoint of water dispersion stability and substrate adhesion.

[0039] If the resin (B) of the present disclosure contains a (meth)acrylic acid ester copolymer, the (meth)acrylic acid ester copolymer has structural units derived from a (meth)acrylic acid ester monomer and can be obtained by polymerizing the (meth)acrylic acid ester monomer. When the emulsion particles of this disclosure contain a (meth)acrylic acid ester copolymer, the (meth)acrylic acid ester monomer preferably has structural units derived from (meth)acrylic acid ester having substituents with 4 to 20 carbon atoms, more preferably has structural units derived from (meth)acrylic acid ester having substituents with 4 to 15 carbon atoms, and even more preferably has structural units derived from (meth)acrylic acid ester having substituents with 4 to 12 carbon atoms.

[0040] When the resin (B) of the present disclosure is a (meth)acrylic acid ester copolymer, examples of (meth)acrylic acid ester monomers include (meth)acrylic acid esters having a linear alkyl group, (meth)acrylic acid esters having a branched alkyl group, (meth)acrylic acid esters having a cyclic alkyl group, and (meth)acrylic acid esters having an aromatic group. (meth)acrylic acid esters having a linear alkyl group, (meth)acrylic acid esters having a branched alkyl group, and (meth)acrylic acid esters having a cyclic alkyl group are preferred, (meth)acrylic acid esters having a linear alkyl group and (meth)acrylic acid esters having a cyclic alkyl group are more preferred, and it is even more preferable to use a combination of (meth)acrylic acid esters having a branched alkyl group and (meth)acrylic acid esters having a cyclic alkyl group.

[0041] Examples of linear alkyl group-containing (meth)acrylic acid esters of this disclosure include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, behenyl (meth)acrylate, methoxyethyl (meth)acrylate, ethyl carbitol (meth)acrylate, ethoxypolyethylene glycol (meth)acrylate, aminoethyl (meth)acrylate, chloroethyl (meth)acrylate, trifluoroethyl (meth)acrylate, and heptadecafluorooctylethyl (meth)acrylate, with butyl (meth)acrylate and lauryl (meth)acrylate being preferred, and lauryl (meth)acrylate being more preferred.

[0042] Examples of (meth)acrylic acid esters having a branched alkyl group in this disclosure include isopropyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, neopentyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)acrylate, isostearyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, methoxytripropylene glycol (meth)acrylate, and hexafluoropropyl (meth)acrylate. Isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, neopentyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and isodecyl (meth)acrylate are preferred, and isobutyl (meth)acrylate, t-butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate are more preferred.

[0043] Examples of (meth)acrylic acid esters having a cyclic alkyl group in this disclosure include cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and dicyclopentenyl (meth)acrylate, with cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, and isobornyl (meth)acrylate being preferred, and cyclohexyl (meth)acrylate and isobornyl (meth)acrylate being more preferred.

[0044] Examples of aromatic group-containing (meth)acrylic acid esters of this disclosure include phenyl (meth)acrylate, 4-t-butylphenyl (meth)acrylate, bromophenyl (meth)acrylate, dibromophenyl (meth)acrylate, 2,4,6-tribromophenyl (meth)acrylate, monochlorophenyl (meth)acrylate, dichlorophenyl (meth)acrylate, trichlorophenyl (meth)acrylate, benzyl (meth)acrylate, naphthyl (meth)acrylate, and the like.

[0045] The content of structural units derived from (meth)acrylic acid esters per 100 parts by mass of resin (B) of the present disclosure is preferably 70 parts by mass or more, more preferably 80 parts by mass or more, and even more preferably 90 parts by mass or more.

[0046] The content of structural units derived from (meth)acrylic acid ester having a branched alkyl group per 100 parts by mass of resin (B) of the present disclosure is preferably 20 parts by mass or more, more preferably 25 parts by mass or more, even more preferably 30 parts by mass or more, preferably 60 parts by mass or less, more preferably 55 parts by mass or less, and even more preferably 50 parts by mass or less.

[0047] The content of structural units derived from (meth)acrylic acid esters having a cyclic alkyl group per 100 parts by mass of resin (B) of the present disclosure is preferably 40 parts by mass or more, more preferably 45 parts by mass or more, even more preferably 50 parts by mass or more, preferably 75 parts by mass or less, more preferably 70 parts by mass or less, and even more preferably 65 parts by mass or less.

[0048] The mass ratio of structural units derived from (meth)acrylic acid ester having a branched alkyl group to structural units derived from (meth)acrylic acid ester having a cyclic alkyl group in resin (B) of the present disclosure (mass of structural units derived from (meth)acrylic acid ester having a branched alkyl group / mass of structural units derived from (meth)acrylic acid ester having a cyclic alkyl group) is preferably 25 / 75 to 60 / 40, more preferably 30 / 70 to 55 / 45, and even more preferably 35 / 65 to 50 / 50.

[0049] When the resin (B) of this disclosure contains a (meth)acrylic acid ester copolymer, from the viewpoint of film-forming properties when used as a gravure printing ink, the amount of structural units derived from methyl methacrylate is preferably 70 parts by mass or less, more preferably 50 parts by mass or less, and even more preferably 30 parts by mass or less per 100 parts by mass of resin (B).

[0050] The resin (B) of this disclosure may have structural units derived from carboxyl group-containing monomers, but from the viewpoint of water resistance of the coating film when used as a gravure printing ink, the content of structural units derived from carboxyl group-containing monomers per 100 parts by mass of emulsion particles is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less, and it is particularly preferable that it does not have structural units derived from carboxyl group-containing monomers. Examples of carboxyl group-containing monomers include the compounds described in resin (A).

[0051] The resin (B) of this disclosure may have structural units derived from aromatic vinyl monomers, but from the viewpoint of substrate adhesion and coating film durability when used as a gravure printing ink, the content of structural units derived from aromatic vinyl monomers per 100 parts by mass of resin (B) is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, even more preferably 5 parts by mass or less, and it is particularly preferable that it does not have structural units derived from aromatic vinyl monomers. Examples of aromatic vinyl monomers include the compounds described for resin (A).

[0052] The resin (B) of this disclosure preferably has monomer-derived structural units with an octanol / water partition coefficient of 3.0 or higher, in order to improve the hydrophobicity of resin (B) and ensure the dispersion stability of the aqueous resin composition when combined with resin (A). Monomers with an octanol / water partition coefficient of 3.0 or higher include cyclohexyl methacrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isodecyl (meth)acrylate, isostearyl (meth)acrylate, 2,2,6,6-tetramethyl-4-piperidyl (meth)acrylate, 1,2,2,6,6-pentamethyl-4-piperidyl (meth)acrylate, 4-tert-butylstyrene, 4-tert-butoxystyrene, and α-methylstyrene. The content of monomer-derived structural units with an octanol / water partition coefficient of 3.0 or higher in resin (B) of this disclosure is preferably 50 parts by mass or more, more preferably 60 parts by mass or more, and even more preferably 70 parts by mass or more, per 100 parts by mass of emulsion particles, from the viewpoint of dispersion stability of emulsion particles and water resistance of the coating film when used as an ink for gravure printing.

[0053] The glass transition temperature of resin (B) of this disclosure is not particularly limited, but is preferably -50°C or higher, more preferably -30°C or higher, and even more preferably -20°C or higher to prevent tack formation in the ink coating, and is preferably 40°C or lower, more preferably 30°C or lower, and even more preferably 20°C or lower for good film formation of the ink. The glass transition temperature of the emulsion particles can be measured or calculated in the same manner as for resin (A). The weight-average molecular weight of resin (B) in this disclosure is preferably 300,000 or more, more preferably 500,000 or more, and even more preferably 1,000,000 or more, from the viewpoint of the durability of the ink print coating. The weight-average molecular weight of the emulsion particles can be measured by the same method as for resin (A).

[0054] The acid value of resin (B) in this disclosure is preferably 50 mg KOH / g or less, more preferably 30 mg KOH / g or less, and even more preferably 20 mg KOH / g or less, from the viewpoint of printability and storage stability when used as a gravure printing ink, and it is particularly preferable that it has no acid value. The acid value of resin (B) in this disclosure indicates the number of milligrams of potassium hydroxide required to neutralize the acidic components contained in 1 g of emulsion particles. It can be calculated using dried resin (B) by a measurement method in accordance with JIS K 5601-2-1, or it can be calculated from the amount of monomers that make up resin (B) charged.

[0055] The resin (B) of the present disclosure may be emulsion particles. Furthermore, the resin (B) of the present disclosure may be a single layer emulsion particle or an emulsion particle having multiple layers. When the resin (B) of this disclosure is a single layer of emulsion particles, the polymer constituting the emulsion particles is as described in the monomers and composition of the resin (B) above. When the resin (B) of this disclosure is a multilayer emulsion particle, it is preferable to have two to four layers, and more preferably two or three layers. In an emulsion particle having a multilayer resin layer structure, the inner layer means the innermost layer of the emulsion particle, the outer layer means the other layers excluding the innermost layer, and the outermost layer means the outermost layer formed. The polymer of each layer constituting the emulsion particle can be the monomer described in the resin (B) above. When the resin (B) of the present disclosure is a multi-layer emulsion particle, the content of structural units derived from (meth)acrylic acid ester with respect to 100 parts by mass of structural units derived from monomers forming the inner layer is preferably 70 parts by mass or more, more preferably 80 parts by mass or more, and even more preferably 90 parts by mass or more.

[0056] When the resin (B) of the present disclosure is a multi-layer emulsion particle, the content of structural units derived from a (meth)acrylic acid ester having a branched alkyl group relative to 100 parts by mass of structural units derived from monomers forming the inner layer is preferably 20 parts by mass or more, more preferably 25 parts by mass or more, even more preferably 30 parts by mass or more, preferably 60 parts by mass or less, more preferably 55 parts by mass or less, and even more preferably 50 parts by mass or less. When the resin (B) of the present disclosure is a multi-layer emulsion particle, the content of structural units derived from a (meth)acrylic acid ester having a cyclic alkyl group, relative to 100 parts by mass of structural units derived from monomers forming the inner layer, is preferably 40 parts by mass or more, more preferably 45 parts by mass or more, even more preferably 50 parts by mass or more, preferably 75 parts by mass or less, more preferably 70 parts by mass or less, and even more preferably 65 parts by mass or less.

[0057] When the resin (B) of the present disclosure is a multi-layer emulsion particle, in the monomer-derived structural units forming the inner layer, the mass ratio of structural units derived from (meth)acrylic acid ester having a branched alkyl group to structural units derived from (meth)acrylic acid ester having a cyclic alkyl group (mass of structural units derived from (meth)acrylic acid ester having a branched alkyl group / mass of structural units derived from (meth)acrylic acid ester having a cyclic alkyl group) is preferably 20 / 80 to 80 / 20, more preferably 35 / 65 to 70 / 30, and even more preferably 50 / 50 to 60 / 40.

[0058] When the resin (B) of the present disclosure is a multi-layer emulsion particle, the content of structural units derived from (meth)acrylic acid ester with respect to 100 parts by mass of structural units derived from monomers forming the outermost layer is preferably 70 parts by mass or more, more preferably 80 parts by mass or more, and even more preferably 90 parts by mass or more. When the resin (B) of the present disclosure is a multi-layer emulsion particle, the content of structural units derived from a (meth)acrylic acid ester having a branched alkyl group relative to 100 parts by mass of structural units derived from the monomer forming the outermost layer is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, even more preferably 20 parts by mass or more, preferably 50 parts by mass or less, more preferably 45 parts by mass or less, and even more preferably 40 parts by mass or less. When the resin (B) of the present disclosure is a multi-layer emulsion particle, the content of structural units derived from a (meth)acrylic acid ester having a cyclic alkyl group, relative to 100 parts by mass of structural units derived from the monomer forming the outermost layer, is preferably 50 parts by mass or more, more preferably 55 parts by mass or more, even more preferably 60 parts by mass or more, preferably 80 parts by mass or less, more preferably 85 parts by mass or less, and even more preferably 90 parts by mass or less.

[0059] When the resin (B) of the present disclosure is a multi-layer emulsion particle, in the monomer-derived structural units forming the outermost layer, the mass ratio of structural units derived from (meth)acrylic acid ester having a branched alkyl group to structural units derived from (meth)acrylic acid ester having a cyclic alkyl group (mass of structural units derived from (meth)acrylic acid ester having a branched alkyl group / mass of structural units derived from (meth)acrylic acid ester having a cyclic alkyl group) is preferably 10 / 90 to 50 / 50, more preferably 15 / 85 to 45 / 55, and even more preferably 20 / 80 to 40 / 60.

[0060] When resin (B) of the present disclosure is a multi-layer emulsion particle, the glass transition temperature for forming the inner layer is not particularly limited, but is preferably -50°C or higher, more preferably -40°C or higher, even more preferably -30°C or higher, and preferably 10°C or lower, more preferably 0°C or lower, and even more preferably -10°C or lower, from the viewpoint of good film formation of the ink. The glass transition temperature for forming the inner layer can be measured or calculated in the same manner as for resin (A).

[0061] When the resin (B) of this disclosure is a multi-layer emulsion particle, the glass transition temperature forming the outermost layer is not particularly limited, but is preferably -10°C or higher, more preferably 0°C or higher, even more preferably 10°C or higher, in order to prevent tack formation in the ink coating film and to achieve both blocking prevention of the coating film, and is preferably 50°C or lower, more preferably 40°C or lower, and even more preferably 30°C or lower for good film formation of the ink. The glass transition temperature forming the outer layer can be measured or calculated in the same manner as for resin (A).

[0062] <Aqueous resin composition> The aqueous resin composition of this disclosure is characterized by containing resin (A) and resin (B). Resin (A) may be partially or entirely dissolved in the aqueous resin composition, or it may be present around resin (B). The non-volatile content of the aqueous resin composition of this disclosure may be calculated as the total mass of the aqueous resin composition minus the mass of volatile components contained in resin (A), resin (B), and various additives, or by weighing 1 g of the aqueous resin composition, drying it in a hot air dryer at a temperature of 150°C for 20 minutes, and using the resulting residue as the non-volatile content, formula: [Non-volatile content (mass%) in aqueous resin compositions] = ([Mass of residue] ÷ [1g of aqueous resin composition]) × 100 It may also be calculated based on this.

[0063] The content of resin (A) per 100 parts by mass of nonvolatile content of the aqueous resin composition of this disclosure is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and even more preferably 25 parts by mass or more, from the viewpoint of dispersion stability of the aqueous resin and the ink using the same. To prevent significant thickening of the aqueous resin composition and to ensure the printability of the ink using the aqueous resin composition, it is preferably 70 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 50 parts by mass or less.

[0064] The content of resin (B) per 100 parts by mass of nonvolatile content of the aqueous resin composition of this disclosure is preferably 30 parts by mass or more, more preferably 40 parts by mass or more, and still more preferably 50 parts by mass or more, in order to ensure adhesion of the ink to the substrate and to form a durable coating film. To ensure film-forming properties of the ink, it is preferably 90 parts by mass or less, more preferably 80 parts by mass or less, and still more preferably 75 parts by mass or less.

[0065] The content of resin (A) and resin (B) per 100 parts by mass of nonvolatile content of the aqueous resin composition of this disclosure is preferably 95 parts by mass or more, more preferably 98 parts by mass or more, and even more preferably 99 parts by mass or more, from the viewpoint of dispersion stability of the aqueous resin composition. In the aqueous resin composition of this disclosure, the mass ratio of resin (A) to resin (B) (mass of resin (A) / mass of resin (B)) is preferably 10 / 90 to 70 / 30, more preferably 15 / 85 to 60 / 40, more preferably 20 / 80 to 50 / 50, and particularly preferably 25 / 75 to 45 / 55.

[0066] The acid value in the nonvolatile content of the aqueous resin composition of this disclosure is preferably less than 60 mg KOH / g, more preferably less than 50 mg KOH / g, and even more preferably less than 40 mg KOH / g, from the viewpoint of suppressing thickening of the aqueous resin composition, printing characteristics when used as a gravure printing ink, or storage stability. The acid value of the nonvolatile content of the aqueous resin composition disclosed herein indicates the number of milligrams of potassium hydroxide required to neutralize the acidic components contained in 1 g of the nonvolatile content of the aqueous resin composition. It can be calculated using the nonvolatile content of the aqueous resin composition by a measurement method in accordance with JIS K 5601-2-1, or it can be calculated from the amount of monomers, etc., that make up resin (A) and resin (B) contained in the aqueous resin composition.

[0067] The glass transition temperature of the nonvolatile components of the aqueous resin composition of this disclosure is not particularly limited, but is preferably -20°C or higher, more preferably -10°C or higher, even more preferably 0°C or higher, and from the viewpoint of good film formation of the ink, preferably 50°C or lower, more preferably 40°C or lower, and even more preferably 30°C or lower.

[0068] The aqueous resin composition of this disclosure preferably contains a basic compound, as this improves the dispersion stability of the resin composition by dissolving resin (A). Examples of basic compounds include ammonia; primary amines such as ethylamine, propylamine, butylamine, benzylamine, monoethanolamine, neopentanolamine, 2-aminopropanol, 3-aminopropanol, and 2-amino-2-methyl-1-propanol; secondary amines such as diethylamine, diethanolamine, di-n- or di-iso-propanolamine, N-methylethanolamine, and N-ethylethanolamine; tertiary amines such as dimethylethanolamine, trimethylamine, triethylamine, triisopropylamine, methyldiethanolamine, and dimethylaminoethanol; and inorganic hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide. Volatile basic compounds are preferred to obtain an ink coating with excellent water resistance. Specifically, ammonia, monoethanolamine, and triethylamine are preferred, and ammonia is more preferred. The basic compounds may also be used in aqueous solution form as needed.

[0069] The content of the basic compound in the aqueous resin of this disclosure is mainly to improve the dispersion stability of the aqueous resin and the ink containing it by dissolving the resin (A) in water. Preferably, the content is equivalent to neutralizing 50% or more of the acid value of the nonvolatile component of the aqueous resin, more preferably equivalent to neutralizing 70% or more, and even more preferably equivalent to neutralizing 90% or more. Furthermore, a content equivalent to neutralizing 150% or less is preferred, a content equivalent to neutralizing 130% or less is more preferred, and a content equivalent to neutralizing 110% or less is even more preferred. The content of the basic compound included in this disclosure is preferably such that it neutralizes 60% or more of the acid value of the nonvolatile component of resin (A), more preferably 75% or more, and even more preferably 90% or more, in order to improve the dispersion stability of aqueous resins and inks containing them by dissolving resin (A) in water.

[0070] The viscosity of the aqueous resin composition of this disclosure at 25°C is not particularly limited, but from the viewpoint of workability in polymerization and ink compounding, it is preferably 10,000 mPa·s or less, and more preferably in the order of 5,000 mPa·s or less, 2,000 mPa·s or less, and 1,000 mPa·s or less.

[0071] If the resin (B) of this disclosure is emulsion particles, the particle size of the emulsion particles contained in the aqueous resin composition is not particularly limited, but from the viewpoint of storage stability, 50 nm or larger is preferred. The particle size of the emulsion particles of this disclosure is not particularly limited, but can be measured by dynamic light scattering, laser diffraction / scattering, Coulter counter, etc.

[0072] In addition to resin (A) and resin (B), the aqueous resin composition of this disclosure may contain appropriate amounts of additives such as surfactants, film-forming aids, ultraviolet absorbers, ultraviolet inhibitors, fillers, leveling agents, dispersants, thickeners, wetting agents, plasticizers, stabilizers, antioxidants, and preservatives, to the extent that the objectives of the present invention are not hindered.

[0073] <Method for producing aqueous resin compositions> In the method for producing the aqueous resin composition for gravure printing of this disclosure, resin (A) may be polymerized in the presence of an aqueous solvent, and then resin (B) may be polymerized in the presence of resin (A), or resin (A) and resin (B) may be polymerized separately in the presence of an aqueous solvent, and then resin (A) and resin (B) may be mixed. From the viewpoint of film-forming properties when used as a gravure printing ink, it is preferable to polymerize resin (B) in the presence of resin (A).

[0074] In the method for producing the aqueous resin composition for gravure printing of this disclosure, the timing of adding the basic compound may be as follows: after polymerizing resin (A), the basic compound may be added and resin (B) may be polymerized in the presence of resin (A) and the basic compound; after polymerizing resin (B) in the presence of resin (A), the basic compound may be added; after polymerizing resin (A) and resin (B) separately, the basic compound may be added to an aqueous dispersion of resin (A) and resin (B) that has been mixed; or resin (B), which has been polymerized separately, may be added to an aqueous dispersion of resin (A) to which the basic compound has been added. From the viewpoint of the dispersion stability during polymerization and of the aqueous resin composition, it is preferable to polymerize resin (A), add the basic compound, and polymerize resin (B) in the presence of resin (A) and the basic compound. The monomers used in resin (A), resin (B), and the composition of the monomers in the method for producing the aqueous dispersion for gravure printing of this disclosure are as described above.

[0075] Examples of polymerization methods for resin (A) and resin (B) contained in the aqueous resin composition for gravure printing of this disclosure include emulsion polymerization, bulk polymerization, solution polymerization, and suspension polymerization, but the present invention is not limited to these examples. Among the methods for polymerizing the monomer components, emulsion polymerization is preferred because an environmentally friendly aqueous dispersion can be directly obtained when the monomer components are polymerized by emulsion polymerization. The resins (A) and (B) contained in the aqueous resin composition for gravure printing of this disclosure can be obtained by polymerization in the presence of an aqueous solvent. Examples of aqueous solvents in this disclosure include, but are not limited to, hydrophilic organic solvents such as monohydric alcohols like methyl alcohol, ethyl alcohol, isopropyl alcohol, n-propyl alcohol, and allyl alcohol; polyhydric alcohols like ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, heptanediol, diethylene glycol, dipropylene glycol, and glycerin; ketones like acetone, methyl ethyl ketone, and methyl propyl ketone; alkyl esters of aliphatic organic acids like methyl formate, ethyl formate, methyl acetate, and methyl acetoacetate; and alkyl ethers of polyhydric alcohols such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and dipropylene glycol monomethyl ether. These aqueous solvents may be used individually or in combination of two or more. Furthermore, the aqueous solvent may contain water in part. From the viewpoint of environmental protection, the water content in 100 parts by mass of the aqueous solvent of this disclosure is preferably 80 parts by mass or more, more preferably 90 parts by mass or more, and particularly preferred in the order of 95 parts by mass or more, 99 parts by mass or more, and 100 parts by mass.

[0076] When emulsion polymerization is performed on resin (A) and resin (B) of the present disclosure, an emulsifier may be used as necessary. Examples of emulsifiers include anionic emulsifiers, nonionic emulsifiers, cationic emulsifiers, amphoteric emulsifiers, and polymer emulsifiers. These emulsifiers may be used individually or in combination of two or more types.

[0077] Examples of anionic emulsifiers include alkyl sulfate salts such as ammonium dodecyl sulfate and sodium dodecyl sulfate; alkyl sulfonate salts such as ammonium dodecyl sulfonate, sodium dodecyl sulfonate, and sodium alkyldiphenyl ether disulfonate; alkylaryl sulfonate salts such as ammonium dodecylbenzene sulfonate and sodium dodecylnaphthalene sulfonate; polyoxyethylene alkyl sulfonate salts; polyoxyethylene alkyl sulfate salts; polyoxyethylene alkylaryl sulfate salts; dialkyl sulfosuccinates; and aryl sulfonic acid-formaldehyde condensates. Examples include fatty acid salts such as ammonium laurylate and sodium stearate; sulfate esters or salts thereof having an allyl group, such as bis(polyoxyethylene polycyclic phenyl ether) methacrylate sulfonate salt, propenyl-alkyl sulfosuccinate salt, (meth)acrylate polyoxyethylene sulfonate salt, (meth)acrylate polyoxyethylene phosphate salt, and sulfonate salt of allyloxymethylalkyloxypolyoxyethylene; sulfate ester salts of allyloxymethyl alkoxyethyl polyoxyethylene, polyoxyalkylene alkenyl ether sulfate ammonium salt, etc., but are not limited to these examples.

[0078] Examples of nonionic emulsifiers include, but are not limited to, polyoxyethylene alkyl ethers, polyoxyethylene alkylaryl ethers, condensates of polyethylene glycol and polypropylene glycol, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, fatty acid monoglycerides, condensation products of ethylene oxide and aliphatic amines, allyloxymethyl alkoxyethyl hydroxypolyoxyethylene, and polyoxyalkylene alkenyl ethers.

[0079] Examples of cationic emulsifiers include alkylammonium salts such as dodecylammonium chloride, but are not limited to these examples.

[0080] Examples of amphoteric emulsifiers include betaine ester type emulsifiers, but the examples are not limited to these.

[0081] Examples of polymer emulsifiers include, but are not limited to, poly(meth)acrylates such as sodium polyacrylate and ammonium polyacrylate; polyvinyl alcohol; polyvinylpyrrolidone; polyhydroxyalkyl (meth)acrylates such as polyhydroxyethyl acrylate; and copolymers in which one or more monomers constituting these polymers are copolymerized components.

[0082] When the aqueous resin composition of this disclosure is used as an ink for gravure printing, an emulsifier having polymerizable groups, i.e., a so-called reactive emulsifier, is preferred in order to improve the water resistance and image uniformity of the coating film, and from the viewpoint of environmental protection, a non-nonylphenyl type emulsifier is preferred.

[0083] Examples of reactive emulsifiers include propenyl-alkyl sulfosuccinate salts, (meth)acrylate polyoxyethylene sulfonate salts, (meth)acrylate polyoxyethylene phosphate salts [e.g., Sanyo Chemical Industries, Ltd., product name: Eleminor RS-30, etc.], polyoxyethylene alkylpropenylphenyl ether sulfonate salts [e.g., Daiichi Kogyo Seiyaku Co., Ltd., product name: Aqualon HS-10, etc.], allyloxymethylalkyloxypolyoxyethylene sulfonate salts [e.g., Daiichi Kogyo Seiyaku Co., Ltd., product name: Aqualon KH-10, etc.], allyloxymethylnonylphenoxyethyl hydroxypolyoxyethylene sulfonate salts [e.g., ADEKA Corporation, product name: Adekarya Soap SE-10, etc.], and allyloxymethyl alkoxyethyl hydroxypolyoxy Examples include ethylene sulfate salts (e.g., ADEKA Corporation, product names: Adekarya Soap SR-10, SR-20, SR-30, etc.), bis(polyoxyethylene polycyclic phenyl ether) methacrylate sulfonate salts (e.g., Nippon Emulsifier Co., Ltd., product name: Antox MS-60, etc.), allyloxymethyl alkoxyethyl hydroxypolyoxyethylene (e.g., ADEKA Corporation, product names: Adekarya Soap ER-10, ER-20, etc.), polyoxyethylene alkylpropenylphenyl ethers (e.g., Daiichi Kogyo Seiyaku Co., Ltd., product name: Aqualon RN-20, etc.), allyloxymethyl nonylphenoxyethyl hydroxypolyoxyethylene (e.g., ADEKA Corporation, product name: Adekarya Soap NE-10, etc.), but are not limited to these examples. Of the emulsifiers mentioned above, allyloxymethyl alkoxyethyl hydroxypolyoxyethylene sulfate salts [for example, ADEKA Corporation, product names: Adekarya Soap SR-10, SR-20, SR-30, etc.] are more preferred from the viewpoint of polymerization stability, dispersion stability, and substrate adhesion and scratch resistance of the gravure printing ink using the obtained aqueous resin composition.

[0084] The amount of emulsifier used per 100 parts by mass of total monomer components during the polymerization of resin (A) and resin (B) is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 2 parts by mass or more, from the viewpoint of improving polymerization stability, and preferably 10 parts by mass or less, and more preferably 5 parts by mass or less, from the viewpoint of improving water resistance, scratch resistance, and blocking resistance.

[0085] When this aqueous resin composition is polymerized by polymerizing resin (A), then adding a basic compound, and polymerizing resin (B) in the presence of resin (A) and the basic compound, the amount of emulsifier used in the polymerization step of resin (B) can be reduced, and water resistance, scratch resistance, and blocking resistance can be improved.

[0086] Water-soluble initiators are preferred as initiators used during the polymerization of resins (A) and (B) of this disclosure. For example, sodium persulfate, potassium persulfate, ammonium persulfate, hydrogen peroxide, etc., can be used. These may be used individually or in combination of two or more. The amount of the water-soluble initiator used is not particularly limited, but it is preferably 0.05 to 5% by weight relative to the total monomers used during the polymerization of resin (A) and resin (B). If too much water-soluble initiator is used, the water resistance may decrease, while if too little is used, the polymerization rate tends to decrease. The water-soluble initiator may be added to the aqueous solvent in advance, or it may be added to the aqueous solvent dropwise along with the monomers. The conditions for polymerization can be appropriately set depending on the composition of the monomer components, but the reaction temperature is preferably 60 to 90°C and the reaction time is preferably 2 to 8 hours. In addition, in polymerization, commonly used emulsifiers other than polymer emulsifiers, such as chain transfer agents and reducing agents, may also be used.

[0087] <Ink for gravure printing> The aqueous resin composition of this disclosure is preferably used as an ink for gravure printing. The gravure printing ink of this disclosure, by containing resin (A) and resin (B), can be used as a gravure printing ink that has excellent film-forming properties and water resistance.

[0088] The gravure printing inks disclosed herein contain colorants. The colorants of this disclosure may be dyes or pigments, but it is preferable to use pigments. The pigments used in the gravure printing inks of this disclosure are not particularly limited, and those used in conventional water-based printing inks can be used. The pigments may be either inorganic or organic pigments. They can also be used individually or in combination of two or more types. Preferred inorganic pigments include, for example, carbon black, titanium dioxide, zinc oxide, magnesium oxide, silica, alumina, red iron oxide, antimony red, cadmium yellow, cobalt blue, Prussian blue, and ultramarine. Preferred organic pigments include, for example, azo pigments, diazo pigments, azo lake pigments, phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, dioxazine pigments, perylene pigments, perinone pigments, thioindigo pigments, anthraquinone pigments, and quinophthalone pigments. The form of the pigment is not particularly limited, but a pigment dispersion in which the pigment is sufficiently stably dispersed in water with a suitable dispersant is preferred.

[0089] When used in a white ink, the resin (A) content in 100 parts by mass of the gravure printing ink of this disclosure may be 3 parts by mass or more, preferably 5 parts by mass or more, more preferably 7 parts by mass or more, may be 30 parts by mass or less, preferably 25 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less, from the viewpoint of printability, storage stability, and dispersion stability. On the other hand, when used in a color ink other than a white ink, the resin (A) content may be 1 part by mass or more, preferably 2 parts by mass or more, more preferably 3 parts by mass or more, may be 25 parts by mass or less, preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less, from the viewpoint of printability and storage stability.

[0090] When used in a white ink, the resin (B) content in 100 parts by mass of the gravure printing ink of this disclosure may be 10 parts by mass or more, preferably 12 parts by mass or more, more preferably 15 parts by mass or more, may be 40 parts by mass or less, preferably 35 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 25 parts by mass or less, from the viewpoint of printability and storage stability. On the other hand, when used in a color ink other than a white ink, the resin (B) content may be 3 parts by mass or more, preferably 5 parts by mass or more, more preferably 7 parts by mass or more, may be 25 parts by mass or less, preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less, from the viewpoint of discharge stability and storage stability.

[0091] The mass ratio of resin (A) to resin (B) in the gravure printing ink of this disclosure (mass of resin (A) / mass of resin (B)) is preferably 10 / 90 to 70 / 30, more preferably 15 / 85 to 60 / 40, even more preferably 20 / 80 to 50 / 50, and particularly preferably 25 / 75 to 45 / 55.

[0092] The viscosity of the gravure printing inks disclosed herein is not particularly limited, but from the viewpoint of printability, it is preferably 5 mPa·s or higher, more preferably 15 mPa·s or higher, and even more preferably 30 mPa·s or higher. From the viewpoint of printability and storage stability, it is preferably 1000 mPa·s or lower, more preferably 750 mPa·s or lower, and even more preferably 500 mPa·s or lower. The Zahn cup viscosity of the gravure printing inks disclosed herein at 25°C is preferably 5 seconds (sec) or more, more preferably 10 seconds or more, even more preferably 12 seconds or more, preferably 40 seconds or less, more preferably 30 seconds or less, and even more preferably 20 seconds or less, measured using cup #3 manufactured by Rigosha Co., Ltd. The non-volatile content of the gravure printing inks disclosed herein is preferably 30% or more, more preferably 40% or more, and even more preferably 45% or more from the viewpoint of drying properties during printing. From the viewpoint of dispersion stability, it is preferably 70% or less, more preferably 60% or less, and even more preferably 55% or less. The non-volatile content of the gravure printing inks disclosed herein may be calculated by subtracting the mass of volatile components contained in resin (A), resin (B), and various additives from the total mass of the gravure printing ink, or by weighing 1 g of gravure printing ink, drying it in a hot air dryer at a temperature of 150°C for 20 minutes, and using the resulting residue as the non-volatile content, using the formula: [Non-volatile content (mass%) in gravure printing inks] = ([Mass of residue] ÷ [1g of gravure printing ink]) × 100 It may also be calculated based on this.

[0093] The gravure printing inks disclosed herein may contain appropriate amounts of additives such as surfactants, film-forming aids, ultraviolet absorbers, ultraviolet inhibitors, fillers, leveling agents, dispersants, thickeners, wetting agents, plasticizers, stabilizers, antioxidants, and preservatives, to the extent that the objectives of the present invention are not hindered. The aqueous resin composition comprising resin (A) and resin (B) according to this disclosure exhibits excellent film-forming properties and pigment dispersibility. Therefore, by using the aqueous resin composition in gravure printing inks, the amount of organic solvent contained in the ink can be reduced. In gravure printing inks, the organic solvent refers to, for example, those used as surfactants, film-forming aids, leveling agents, wetting agents, etc.

[0094] The aqueous resin composition for gravure printing or the gravure printing ink of this disclosure can be applied to a recording medium (substrate) to form prints or images. Examples of recording media include paper, paper laminated with resin films such as polyethylene, polypropylene, and polystyrene (such as coated paper), metal plates such as aluminum, zinc, and copper, resin films such as cellulose, polyethylene terephthalate, polystyrene, olefin resins, polycarbonate, polyvinyl acetal, polyvinyl chloride, polyamide, nylon, and acrylic resins, paper with a metal coating, and resin films with a metal coating. Resin films are preferred as recording media for printing the aqueous ink of this disclosure, and among these, application to polyethylene terephthalate and olefin resins is preferred. Examples of olefin resins include polyethylene and polypropylene, with particular preference for application to polypropylene such as biaxially oriented polypropylene film (OPP) and unoriented polypropylene film (CPP). The above resin film may be subjected to corona surface treatment as needed to improve the adhesion of the ink to the substrate.

[0095] The aqueous ink of this disclosure is preferably formed on a resin film, and the embodiment thereof is a laminate having a printed layer formed from the aqueous ink on the resin film. The laminate of this disclosure may or may not have a primer layer between the resin film and the printed layer, but from the viewpoint of productivity it is preferable not to have one, and it is preferable to form the printed layer directly on the resin film. The laminate of this disclosure is laminated in the order of resin film and printed layer, and may or may not have a protective film (laminate layer) on the printed layer, but from the viewpoint of productivity it is preferable not to have one. By using the aqueous ink of this disclosure, it is expected that a laminate can be obtained that has excellent adhesion to the substrate and good scratch resistance even without a primer layer or protective film (laminate layer). The laminate of this disclosure can be suitably used in various printed materials. [Examples]

[0096] The present invention will now be described in more detail based on examples, but the present invention is not limited to these examples. In the following examples, unless otherwise specified, "parts" means "parts by mass" and "%" means "percent mass". <Non-volatile content> The total mass of the aqueous resin composition was calculated by subtracting the mass of volatile components contained in resin (A), resin (B), and various additives. The volatile components of the aqueous resin compositions described in this example and comparative example were the following compounds. BDG (Diethylene glycol monobutyl ether) <Glass transition temperature of non-volatile components> The glass transition temperature (Tg) of the non-volatile component is calculated using the glass transition temperature of the monomer homopolymer used in the monomer components that make up the polymer components contained in resin (A) and / or resin (B), using the formula: 1 / Tg = Σ(Wm / Tgm) / 100 [In the formula, Wm represents the content (mass%) of monomer m in the monomer components constituting the polymer component, and Tgm represents the glass transition temperature (absolute temperature: K) of the monomer m homopolymer.] It was calculated based on Fox's formula, which is expressed as follows:

[0097] <Acid value derived from carboxyl groups of non-volatile components> The acid value derived from the carboxyl groups of the non-volatile components was calculated by determining the amount of potassium hydroxide in mg required to neutralize the carboxyl groups present in 1 g of monomer components constituting the polymer components contained in resin (A) and / or resin (B). <Average particle size> Using a multi-sample nanoparticle diameter measurement system [manufactured by Otsuka Electronics Co., Ltd., product name: nanoSAQLA], a particle size measurement device using dynamic light scattering at a measurement temperature of 25±0.5℃, the autocorrelation function was determined by photon correlation spectroscopy, and the volume-average particle diameter (hydrodynamic diameter) was determined by cumulant analysis.

[0098] The abbreviations used in the description of the examples have the following meanings: CHMA: Cyclohexyl methacrylate EA: Ethyl acrylate 2-EHA:2-Ethylhexylacrylate HEMA: Hydroxyethyl methacrylate LMA: Lauryl methacrylate MMA: Methyl methacrylate St: Styrene THFA: Tetrahydrofurfurylacrylate AA: Acrylic acid MAA: Methacrylic acid TDM: tert-dodecyl mercaptan SR-20: Reactive emulsifier (ether sulfate type ammonium salt) [Manufactured by ADEKA Corporation, product name: Adekaryasorb SR-20] APS: Ammonium persulfate KPS: Potassium persulfate Joncryl 60J: Water-soluble styrene-acrylic resin [Manufactured by BASF, non-volatile content 34%, acid value in non-volatile content 215, glass transition temperature 85°C] BDG: Diethylene glycol monobutyl ether Olphine D-10PG: Acetylene-based surfactant [Manufactured by Nisshin Chemical Industry Co., Ltd.] SND-777 (SN Deformer 777): A mixture of mineral oil, polyether, silica, water, etc. [Manufactured by Sunopco Corporation]

[0099] <Aqueous resin composition containing resin (A) and resin (B)> [Manufacturing Example 1] 326 parts of deionized water were placed in a flask equipped with a dropping funnel, stirrer, nitrogen gas inlet tube, thermometer, and reflux condenser, and the temperature was raised to 72°C under nitrogen gas flow. A first-stage dropwise pre-emulsion was prepared in the dropping funnel, consisting of 71 parts of deionized water, 5 parts of SR-20, 82 parts of MMA, 53 parts of EA, 19 parts of MAA, and 8 parts of TDM. 7 parts of this pre-emulsion, representing 3% of the total volume, were added to the flask, followed by the addition of 22 parts of 5% APS aqueous solution to initiate polymerization. The remaining portion of the dropwise pre-emulsion was then uniformly added to the flask over 90 minutes. After the dropwise addition was complete, the contents of the flask were maintained at 75°C for 25 minutes to obtain a resin (A) dispersion. Subsequently, 15 parts of aqueous ammonia (25%) were slowly added to the resin (A) dispersion while thoroughly stirring to dissolve the resin (A), and the contents of the flask were maintained at 78°C for 15 minutes. A second-stage pre-emulsion was prepared in a dropping funnel, consisting of 50 parts deionized water, 1 part SR-20, 53 parts CHMA, and 62 parts 2-EHA. Three parts of this pre-emulsion, representing 2% of the total volume, were added to the flask. The remaining pre-emulsion was then uniformly added to the flask dropwise over 50 minutes. After the addition was complete, the contents of the flask were maintained at 78°C for 30 minutes. A third-stage pre-emulsion was prepared in a dropping funnel, consisting of 50 parts deionized water, 1 part SR-20, 82 parts CHMA, and 33 parts 2-EHA. This pre-emulsion was uniformly added to the flask dropwise over 50 minutes. After the addition was complete, 12 parts of a 2% APS aqueous solution were uniformly added to the flask dropwise over 30 minutes. After the addition was complete, the contents of the flask were maintained at 78°C for 60 minutes. The resulting reaction solution was cooled to room temperature and then filtered through a 300-mesh wire mesh to obtain aqueous resin composition 1 containing resin (A) and resin (B). The non-volatile content of aqueous resin composition 1 was 40%, the acid value of the non-volatile content was 32 mg KOH / g, and the glass transition temperature of the non-volatile content was 17°C. The average particle size was 65 nm.

[0100] [Manufacturing Example 2] In Production Example 2, an aqueous resin composition 2 containing resin (A) and resin (B) was obtained in the same manner as in Production Example 1, except that the first-stage drop-feed preemulsion consisted of 71 parts deionized water, 5 parts SR-20, 92 parts MMA, 42 parts EA, 19 parts MAA, and 8 parts TDM; the second-stage drop-feed preemulsion consisted of 50 parts deionized water, 1 part SR-20, 61 parts CHMA, and 54 parts 2-EHA; and the third-stage drop-feed preemulsion consisted of 50 parts deionized water, 1 part SR-20, 89 parts CHMA, and 27 parts 2-EHA. The non-volatile content of the aqueous resin composition 2 was 45%, the acid value of the non-volatile content was 32 mgKOH / g, and the glass transition temperature of the non-volatile content was 27°C. The average particle size was 71 nm.

[0101] [Manufacturing Example 3] 329 parts of deionized water were placed in a flask equipped with a dropping funnel, stirrer, nitrogen gas inlet tube, thermometer, and reflux condenser, and the temperature was raised to 72°C under nitrogen gas flow. A first-stage dropwise pre-emulsion was prepared in the dropping funnel, consisting of 54 parts of deionized water, 3 parts of SR-20, 61 parts of MMA, 40 parts of EA, 15 parts of MAA, and 8 parts of TDM. 5 parts of this pre-emulsion, representing 3% of the total volume, were added to the flask, followed by the addition of 22 parts of 5% APS aqueous solution to initiate polymerization. The remaining portion of the dropwise pre-emulsion was then uniformly added to the flask over 90 minutes. After the dropwise addition was complete, the contents of the flask were maintained at 75°C for 25 minutes to obtain a resin (A) dispersion. Subsequently, 12 parts of aqueous ammonia (25%) were slowly added to the resin (A) dispersion while thoroughly stirring to dissolve the resin (A), and then the contents of the flask were maintained at 78°C for 15 minutes. A second-stage pre-emulsion was prepared in a dropping funnel, consisting of 58 parts deionized water, 1 part SR-20, 62 parts CHMA, and 73 parts 2-EHA. 4 parts of this pre-emulsion (2% of the total volume) were added to the flask, and the remaining pre-emulsion was uniformly added to the flask over 50 minutes. After the addition was complete, the contents of the flask were maintained at 78°C for 30 minutes. A third-stage pre-emulsion was prepared in a dropping funnel, consisting of 58 parts deionized water, 1 part SR-20, 96 parts CHMA, and 38 parts 2-EHA. This pre-emulsion was uniformly added to the flask over 50 minutes. After the addition was complete, 12 parts of a 2% APS aqueous solution were uniformly added to the flask over 30 minutes. After the addition was complete, the contents of the flask were maintained at 78°C for 60 minutes. The resulting reaction solution was cooled to room temperature and then filtered through a 300-mesh wire mesh to obtain aqueous resin composition 3 containing resin (A) and resin (B). The non-volatile content of the aqueous resin composition 3 was 40%, the acid value of the non-volatile content was 24 mg KOH / g, and the glass transition temperature of the non-volatile content was 12°C. The average particle size was 90 nm.

[0102] [Manufacturing Example 4] 207 parts of deionized water were placed in a flask equipped with a dropping funnel, stirrer, nitrogen gas inlet tube, thermometer, and reflux condenser, and the temperature was raised to 72°C under nitrogen gas flow. A first-stage dropwise pre-emulsion was prepared in the dropping funnel, consisting of 80 parts of deionized water, 5 parts of SR-20, 123 parts of MMA, 29 parts of 2-EHA, 22 parts of MAA, and 9 parts of TDM. 8 parts of this pre-emulsion, representing 3% of the total volume, were added to the flask, followed by the addition of 24 parts of 5% APS aqueous solution to initiate polymerization. The remaining portion of the dropwise pre-emulsion was then uniformly added to the flask over 90 minutes. After the dropwise addition was complete, the contents of the flask were maintained at 75°C for 25 minutes to obtain a resin (A) dispersion. Subsequently, 16 parts of aqueous ammonia (25%) were slowly added to the resin (A) dispersion while thoroughly stirring to dissolve the resin (A), and then the contents of the flask were maintained at 78°C for 15 minutes. A second-stage monomer solution consisting of 56 parts MMA and 74 parts 2-EHA was prepared in a dropping funnel, and 26 parts (20% of the total volume) were added to the flask. 189 parts water was measured out into another dropping funnel to serve as the second-stage water solution. The remaining monomer solution and the water solution were then uniformly added to the flask over 40 minutes. After the addition was complete, the contents of the flask were maintained at 78°C for 30 minutes. A third-stage monomer solution consisting of 93 parts CHMA and 37 parts 2-EHA was prepared in a dropping funnel. 189 parts water was measured out into another dropping funnel to serve as the third-stage water solution. The remaining monomer solution and the water solution were then uniformly added to the flask over 50 minutes. After the addition was complete, 13 parts of a 2% APS aqueous solution were uniformly added to the flask over 30 minutes. After the addition was complete, the contents of the flask were maintained at 78°C for 60 minutes. The resulting reaction solution was cooled to room temperature and then filtered through a 300-mesh wire mesh to obtain aqueous resin composition 4 containing resin (A) and resin (B). The non-volatile content of the aqueous resin composition 4 was 45%, the acid value of the non-volatile content was 32 mg KOH / g, and the glass transition temperature of the non-volatile content was 20°C. The average particle size was 56 nm.

[0103] [Manufacturing Example 5] In Production Example 5, an aqueous resin composition 5 containing resin (A) and resin (B) was obtained in the same manner as in Production Example 4, except that the first-stage drop-feed preemulsion consisted of 80 parts deionized water, 5 parts SR-20, 116 parts MMA, 36 parts 2-EHA, 22 parts MAA, and 9 parts TDM; the second-stage drop-feed monomer solution consisted of 44 parts MMA and 86 parts 2-EHA; and the third-stage monomer solution consisted of 74 parts MMA and 56 parts 2-EHA. The non-volatile content of the aqueous resin composition 5 was 45%, the acid value of the non-volatile content was 32 mgKOH / g, and the glass transition temperature of the non-volatile content was 7°C. The average particle size was 52 nm.

[0104] <Aqueous resin composition containing resin (A)> [Manufacturing Example 6] 302 parts of deionized water were placed in a flask equipped with a dropping funnel, stirrer, nitrogen gas inlet tube, thermometer, and reflux condenser, and the temperature was raised to 72°C under nitrogen gas flow. A dropwise pre-emulsion was prepared in the dropping funnel, consisting of 192 parts of deionized water, 12 parts of SR-20, 221 parts of MMA, 142 parts of EA, 52 parts of MAA, and 21 parts of TDM. 19 parts of this pre-emulsion, representing 3% of the total volume, were added to the flask, followed by the addition of 23 parts of a 5% APS aqueous solution to initiate polymerization. The remaining portion of the dropwise pre-emulsion was then uniformly added to the flask over 90 minutes. After the dropwise addition was complete, the contents of the flask were maintained at 75°C for 60 minutes. The resulting reaction solution was cooled to room temperature and then filtered through a 300-mesh wire mesh to obtain aqueous resin composition 6 containing resin (A). The non-volatile content of the aqueous resin composition 6 was 45%, the acid value of the non-volatile content was 76 mgKOH / g, and the glass transition temperature of the non-volatile content was 50°C. The average particle size was 158 nm.

[0105] [Manufacturing Example 7] In Production Example 7, an aqueous resin composition 7 containing resin (A) was prepared in the same manner as in Production Example 6, except that the dropper pre-emulsion consisted of 192 parts deionized water, 12 parts SR-20, 62 parts St, 216 parts MMA, 85 parts 2-EHA, 52 parts MAA, and 21 parts TDM. The non-volatile content of the aqueous resin composition 7 was 45%, the acid value of the non-volatile content was 76 mgKOH / g, and the glass transition temperature of the non-volatile content was 50°C. The average particle size was 152 nm.

[0106] [Manufacturing Example 8] In Production Example 8, an aqueous resin composition 8 containing resin (A) was prepared in the same manner as in Production Example 6, except that the dropper pre-emulsion consisted of 192 parts deionized water, 12 parts SR-20, 187 parts MMA, 166 parts THFA, 62 parts MAA, and 21 parts TDM. The non-volatile content of the aqueous resin composition 8 was 45%, the acid value of the non-volatile content was 91 mg KOH / g, and the glass transition temperature of the non-volatile content was 50°C. The average particle size was 137 nm.

[0107] [Manufacturing Example 9] In a flask equipped with a dropping funnel, stirrer, nitrogen gas inlet tube, thermometer, and reflux condenser, 248 parts deionized water, 3 parts SR-20, and 3 parts emulsifier [Kao Corporation, product name: Perex SS-H, hereinafter referred to as SS-H] were charged, and the mixture was heated to 72°C under nitrogen gas flow. A dropwise pre-emulsion was prepared in the dropping funnel, consisting of 238 parts deionized water, 3 parts SR-20, 3 parts SS-H, 129 parts MAA, and 193 parts EA, and 28 parts (5% of the total volume) were added to the flask. Next, 153 parts of a 0.5% APS aqueous solution were prepared in another dropping funnel, and 8 parts of this solution were added to initiate polymerization. Subsequently, the remaining portion of the dropwise pre-emulsion and the remaining portion of the APS aqueous solution were uniformly added to the flask in parallel over a period of 180 minutes. After the dropwise addition was complete, the contents of the flask were maintained at 75°C for 60 minutes. The resulting reaction solution was cooled to room temperature and then filtered through a 300-mesh wire mesh to obtain an aqueous resin composition 9 containing resin (A). The non-volatile content of the aqueous resin composition 9 was 30%, the acid value of the non-volatile content was 242 mg KOH / g, and the glass transition temperature of the non-volatile content was 22°C. The average particle size was 88 nm.

[0108] <Aqueous resin composition containing resin (B)> [Manufacturing Example 10] 252 parts of deionized water were placed in a flask equipped with a dropping funnel, stirrer, nitrogen gas inlet tube, thermometer, and reflux condenser, and the temperature was raised to 78°C under nitrogen gas flow. A first-stage pre-emulsion was prepared in the dropping funnel, consisting of 96 parts of deionized water, 4 parts of SR-20, 101 parts of CHMA, and 119 parts of 2-EHA. 6 parts of this pre-emulsion (2% of the total volume) were added to the flask, followed by the addition of 26 parts of 5% APS aqueous solution to initiate polymerization. The remaining pre-emulsion was then uniformly added to the flask dropwise over 50 minutes. After the dropwise addition was complete, the contents of the flask were maintained at 78°C for 30 minutes. A second-stage pre-emulsion was prepared in the dropping funnel, consisting of 96 parts of deionized water, 4 parts of SR-20, 157 parts of CHMA, and 63 parts of 2-EHA, and uniformly added to the flask dropwise over 50 minutes. After the dropwise addition was complete, the contents of the flask were maintained at 78°C for 60 minutes. The resulting reaction solution was cooled to room temperature and then filtered through a 300-mesh wire mesh to obtain an aqueous resin composition 10 containing resin (B). The non-volatile content of the aqueous resin composition 10 was 45%, the acid value of the non-volatile content was 0 mgKOH / g, and the glass transition temperature of the non-volatile content was -1.5°C. The average particle size was 276 nm.

[0109] [Manufacturing Example 11] In Production Example 11, an aqueous resin composition 11 containing resin (B) was prepared in the same manner as in Production Example 10, except that the pre-emulsion for the first stage drop-feeding consisted of 96 parts deionized water, 4 parts SR-20, 94 parts MMA, and 126 parts 2-EHA, and the pre-emulsion for the second stage drop-feeding consisted of 96 parts deionized water, 4 parts SR-20, 157 parts CHMA, 49 parts 2-EHA, and 14 parts LMA. The non-volatile content of the aqueous resin composition 11 was 45%, the acid value of the non-volatile content was 0 mgKOH / g, and the glass transition temperature of the non-volatile content was -1.5°C. The average particle size was 281 nm.

[0110] [Manufacturing Example 12] 283 parts of deionized water were placed in a flask equipped with a dropping funnel, stirrer, nitrogen gas inlet tube, thermometer, and reflux condenser, and the temperature was raised to 78°C under nitrogen gas flow. A dropwise pre-emulsion was prepared in the dropping funnel, consisting of 192 parts of deionized water, 12 parts of SR-20, and 36 parts of St4, and 6 parts of this pre-emulsion (1% of the total volume) was added to the flask. While heating and controlling the flask temperature to 88°C, 13 parts of 5% KPS aqueous solution were added to initiate polymerization. The remaining portion of the dropwise pre-emulsion and 19 parts of 3.5% KPS aqueous solution were added to the flask uniformly in parallel over 150 minutes. After the dropwise addition was complete, the contents of the flask were maintained at 88°C for 45 minutes. 8 parts of 10% sodium bicarbonate aqueous solution were added, and the contents of the flask were further maintained at 88°C for 180 minutes. The resulting reaction solution was cooled to room temperature and then filtered through a 300-mesh wire mesh to obtain an aqueous resin composition 12 containing resin (B). The non-volatile content of the aqueous resin composition 12 was 45%, the acid value of the non-volatile content was 0 mgKOH / g, and the glass transition temperature of the non-volatile content was 100°C. The average particle size was 143 nm.

[0111] [Manufacturing Example 13] In a flask equipped with a dropping funnel, stirrer, nitrogen gas inlet tube, thermometer, and reflux condenser, 428 parts of deionized water and 2 parts of emulsifier [manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name: Aqualon RN-20, hereinafter referred to as RN-20] were charged, and the temperature was raised to 50°C under nitrogen gas flow. A dropwise pre-emulsion was prepared in the dropping funnel, consisting of 123 parts of deionized water, 5 parts of RN-20, 341 parts of MMA, 46 parts of EA, 4 parts of HEMA, and 6 parts of AA, and 42 parts, representing 8% of the total volume, were added to the flask. Next, 16 parts of 5% KPS aqueous solution were added, and polymerization was started. After that, the temperature was raised to 75°C, and the remaining dropwise pre-emulsion was uniformly added to the flask over 180 minutes. After the dropwise addition was complete, the contents of the flask were maintained at 75°C for 60 minutes. The pH was adjusted to 9-10 by adding 25% aqueous ammonia, and the resulting reaction solution was cooled to room temperature and then filtered through a 300-mesh wire mesh to obtain an aqueous resin composition 13 containing resin (B). The non-volatile content of the aqueous resin composition 13 was 40%, the acid value of the non-volatile content was 12 mg KOH / g, and the glass transition temperature of the non-volatile content was 83°C. The average particle size was 139 nm.

[0112] <White paste> [Manufacturing Example 14] A white paste was prepared by dispersing 428 parts of deionized water, 50 parts of a dispersant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name: Discoat N-14), 60 parts of propylene glycol, 1000 parts of titanium dioxide (manufactured by Ishihara Sangyo Co., Ltd., product number: CR-95, average particle size: 0.28 μm), and 200 parts of glass beads (diameter: 1 mm) as a dispersion medium in a homodisperser at a rotation speed of 3000 min-1 for 120 minutes, and then filtering through a 300-mesh wire mesh.

[0113] [Example 1] In Production Example 1, aqueous resin composition 1 was taken into a container in a solid content of 22.5 parts. While stirring with a homodisper at a rotation speed of 1000 min-1, 3 parts of BDG and 2 parts of water were added. Then, 22.5 parts of white paste, 0.50 parts of additive [Orphine D-10PG, manufactured by Nisshin Chemical Industry Co., Ltd.], 0.10 parts of defoaming agent [Sannopco Co., Ltd., product name: SND-777], and ion-exchanged water were added to make a total of 100 parts. After stirring for another 20 minutes, aqueous ink 1 was prepared by filtering through a 300-mesh wire mesh. The composition, physical properties, and various evaluation results of aqueous ink 1 are shown in Table 1.

[0114] [Examples 2-9, Comparative Examples 1-6] For the aqueous inks of Example 2-9 and Comparative Example 1-6, the same procedure as in Example 1 was followed, except that the composition was changed as shown in Tables 1 and 2, to prepare the aqueous inks of Example 2-9 and Comparative Example 1-6. A thickening agent [ADEKA Corporation, product name: Adekanol UH-420] was added as needed to adjust the viscosity. The composition, physical properties, and various evaluation results of the aqueous inks of Example 2-9 and Comparative Example 1-6 are shown in Table 1-3. <Viscosity of water-based ink> Water-based ink, which had been temperature-controlled for 30 minutes or more in a constant-temperature bath adjusted to 25°C, was used, and the distillation time of the water-based ink was measured using a Zahn cup #3 (manufactured by Rigosha Co., Ltd.). This value was defined as the viscosity of the Zahn cup.

[0115] <Production of gravure printed materials> The aqueous inks produced in the Examples and Comparative Examples were used for printing on a desktop gravure printing press (manufactured by RK Print-Coat Instruments Ltd., product name: KPrinting Proofer). A solid color plate with 150 lines / inch was used as the printing plate. Corona-treated OPP film (manufactured by Futamura Chemical Co., Ltd., product name: FOR-AQ#30) was used as the printing film, and it was fixed to the printing cylinder roll so that the longitudinal direction of the film and the transport direction were in the same direction. The printing speed was 40 m / min, and the film was dried for 1 minute in a constant temperature dryer at 70°C immediately after printing to obtain a test sheet.

[0116] -Evaluation Method- <Image Quality> The above test sheet was placed on a black board and visually inspected. If the ink was printed evenly on the solid colored surface, it was evaluated as ○; if there were printing defects such as unevenness or flaws, it was evaluated as ×. <Water resistance> A small piece of paper wiper moistened with deionized water was placed on the printed surface of the test sheet, and pressed firmly with the pad of a finger while moving it back and forth 10 times in the printing direction. The condition of the coating after removing the piece was visually observed, and the water resistance was evaluated based on the following evaluation criteria. The evaluation results for each example and comparative example are shown in Tables 1 and 2. [Evaluation Criteria] 5: The image does not peel off at all even when the printed surface is rubbed. 4: If you rub the printed surface, the image will peel off very slightly. 3: Rubbing the printed surface may cause the image to peel off slightly. 2: If you rub the printed surface, the image will peel off slightly. 1: The image clearly peels off when the printed surface is rubbed.

[0117] <Adhesion> Adhesive tape (Nichiban Co., Ltd., Cellotape® No. 405, 24 mm wide) was applied to the test sheet at room temperature, and pressed firmly with the pad of a finger 10 times back and forth in the printing direction. After that, it was peeled off in a 90° direction, and the adhesion was evaluated based on the following evaluation criteria. The evaluation results for each example and comparative example are shown in Tables 1 and 2. [Evaluation Criteria] 5: The printed image does not peel off at all. 4. 1-20% of the printed image peels off. 3. 21-50% of the printed image peels off. 2: 51-75% of the printed image peels off. 1: 76-100% of the printed image peels off. <Storage Stability> The resulting water-based ink is placed in a sealed container and stored in a 50°C constant temperature bath for two months. The Zahn cup viscosity was measured before and after storage, and the ratio (viscosity after storage / viscosity before storage) was calculated. Storage stability was then evaluated based on the following evaluation criteria. [Evaluation Criteria] 5: Ratio is less than 1 to 1.05 4: Ratio is between 1.05 and less than 1.50 3: Ratio is between 1.50 and less than 2.0 2: Ratio is between 2.0 and less than 5.0 1: Ratio of 5.0 or gelation

[0118] [Table 1]

[0119] *1 The values ​​in the formulation table indicate the solid content (excluding the volatile component BDG). *2 The values ​​in the formulation table are calculated based on 100% ammonia. In actual manufacturing, 25% aqueous ammonia solution is used for ammonia addition. *3 For measuring Zahn cup viscosity, use cup No. 3 (manufactured by Rigosha Co., Ltd.).

[0120] [Table 2]

[0121] *1 The values ​​in the formulation table indicate the solid content (excluding the volatile component BDG). *2 The values ​​in the formulation table are calculated based on 100% ammonia. In actual manufacturing, 25% aqueous ammonia solution is used for ammonia addition. *3 For measuring Zahn cup viscosity, use cup No. 3 (manufactured by Rigosha Co., Ltd.).

[0122] [Table 3]

[0123] *1 The values ​​in the formulation table indicate the solid content (excluding the volatile component BDG). *2 The values ​​in the formulation table are calculated based on 100% ammonia. In actual manufacturing, 25% aqueous ammonia solution is used for ammonia addition. *3 For measuring Zahn cup viscosity, use cup No. 3 (manufactured by Rigosha Co., Ltd.).

[0124] Tables 1, 2, and 3 clearly show that the aqueous gravure inks of Examples 1 to 9 have superior storage stability, as well as better image quality, water resistance, and adhesion to the substrate of printed materials using the inks, compared to the aqueous gravure inks of Comparative Examples 1 to 6. Therefore, by using the aqueous resin composition of the present invention, it is possible to obtain a more useful aqueous ink than conventional ones.

Claims

1. An aqueous resin composition for gravure printing comprising resin (A) and resin (B), wherein the acid value in the nonvolatile content of the aqueous resin composition is less than 50 mgKOH / g, and the glass transition temperature in the nonvolatile content of the aqueous resin composition is 50°C or lower, wherein resin (B) has 50 parts by mass or more of monomer-derived structural units with an octanol / water partition coefficient of 3.0 or more per 100 parts by mass of resin (B), The acid value of the resin (A) is 30 mg KOH / g or more and less than 100 mg KOH / g. An aqueous resin composition for gravure printing, wherein the content of structural units derived from aromatic vinyl monomers per 100 parts by mass of the resin (A) is 15 parts by mass or less.

2. The aqueous resin composition for gravure printing according to claim 1, wherein the resin (B) contains 60 parts by mass or less of structural units derived from methyl methacrylate per 100 parts by mass of resin (B).

3. The aqueous resin composition for gravure printing according to claim 1 or 2, wherein the resin (B) has structural units derived from (meth)acrylic acid esters having substituents with 4 to 20 carbon atoms.

4. The aqueous resin composition for gravure printing according to any one of claims 1 to 3, wherein the resin (A) has 60 parts by mass or more of monomer-derived structural units having an octanol / water partition coefficient of 2.5 or less per 100 parts by mass of resin (A).

5. The aqueous resin composition for gravure printing according to any one of claims 1 to 4, wherein the resin (A) contains 20 parts by mass or less of structural units derived from (meth)acrylic acid per 100 parts by mass of resin (A).

6. The aqueous resin composition for gravure printing according to any one of claims 1 to 5, further containing a basic compound.

7. A gravure printing ink containing the aqueous resin composition for gravure printing described in any one of claims 1 to 6.

8. A printed article using an aqueous resin composition for gravure printing according to any one of claims 1 to 6, or a gravure printing ink according to claim 7.

9. The printed material according to claim 8, wherein the base material of the printed material is a resin film.

10. A method for producing an aqueous resin composition for gravure printing comprising resin (A) and resin (B), wherein the acid value in the nonvolatile content of the aqueous resin composition is less than 50 mg KOH / g, and the glass transition temperature in the nonvolatile content of the aqueous resin composition is 50°C or lower, the method comprising the step of polymerizing resin (B) in the presence of resin (A).

11. A method for producing an aqueous resin composition for gravure printing according to claim 10, wherein the resin (B) has 50 parts by mass or more of monomer-derived structural units having an octanol / water partition coefficient of 3.0 or more per 100 parts by mass of resin (B).

12. A method for producing an aqueous resin composition for gravure printing according to claim 10 or 11, wherein the resin (A) has 60 parts by mass or more of monomer-derived structural units with an octanol / water partition coefficient of 2.5 or less per 100 parts by mass of resin (A).

13. A method for producing an aqueous resin composition for gravure printing according to any one of claims 10 to 12, further comprising a basic compound.

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