Aqueous ink composition, aqueous ink set, film with ink layer, method for producing the same, laminate film and packaging material

Abstract

To provide an aqueous ink composition which is excellent in alcohol dilution property and ink followability.SOLUTION: An aqueous ink composition contains an aqueous urethane resin and an aqueous medium, wherein the aqueous urethane resin contains an aqueous urethane resin (A1) and an aqueous urethane resin (A2), the aqueous urethane resin (A1) is an ether-based urethane resin having a glass transition temperature of -70 to -30°C, the aqueous urethane resin (A2) is an ester-based urethane resin having a glass transition temperature of 60 to 120°C, and the content of the total of the aqueous urethane resin (A1) and the aqueous urethane resin (A2) is 20 to 94 mass% with respect to the total mass of a non-volatile content in the aqueous ink composition.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an aqueous ink composition, an aqueous ink set, a film with an ink layer, a method for producing the same, a laminate film, and a packaging material.

Background Art

[0002] For flexible packaging materials such as plastic films used for packaging foods, daily necessities, etc., design and functionality are displayed using gravure printing or flexographic printing. Conventionally, as inks for flexible packaging, oil-based inks using organic solvents as a medium have been mainstream. In recent years, however, there has been an increasing demand for water-based inks using water as a medium from the perspective of environmental issues and the like.

[0003] As water-based inks, those containing acrylic resins or urethane resins as binder resins are known. As urethane resins, various types such as ester-based, ether-based, and carbonate-based are known. Patent Document 1 discloses an aqueous ink containing an ester-based urethane resin and an ether-based urethane resin.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Water-based inks are more difficult to dry than oil-based inks. When printing an ink on a substrate film such as a plastic film to form a coating film, if the drying of the medium is insufficient, blocking may occur when the printed substrate film is wound up. In addition, since the surface tension of water in water-based inks is large, the printed ink may not spread sufficiently, and leveling defects may occur.

[0006] By diluting the water-based ink with alcohol, the drying speed can be increased, the blocking resistance can be improved, and by reducing the surface tension, the leveling property can be improved. However, in the prior art, including the water-based ink described in Patent Document 1, it has not been possible to sufficiently improve the alcohol dilutability, pigment dispersibility, and ink fluidity. When an ester-based urethane resin or a carbonate-based urethane resin is blended into a water-based ink, the alcohol dilutability is improved, but the ink fluidity tends to decrease. When the ink fluidity decreases, it becomes difficult to handle the ink and the storage stability of the ink also decreases. When an ether-based urethane resin is blended into a water-based ink, the ink fluidity is improved, but the alcohol dilutability decreases. When the alcohol dilutability decreases, it becomes easy for thickening or whitening of the printed coating film to occur when diluted with alcohol, making it difficult to blend a large amount of alcohol.

[0007] Therefore, an object of the present invention is to provide a water-based ink composition and a water-based ink set excellent in alcohol dilutability and ink fluidity, an ink layer-attached film using the water-based ink composition, a method for producing the same, a laminate film, and a packaging material.

Means for Solving the Problems

[0008] The present invention has the following aspects. [1] A water-based ink composition containing a water-based urethane resin and a water-based medium, wherein the water-based urethane resin contains a water-based urethane resin (A1) and a water-based urethane resin (A2), the water-based urethane resin (A1) is an ether-based urethane resin having a glass transition temperature of -70 to -30°C, the water-based urethane resin (A2) is an ester-based urethane resin having a glass transition temperature of 60 to 120°C, and the total content of the water-based urethane resin (A1) and the water-based urethane resin (A2) is 20 to 94% by mass based on the total mass of the non-volatile components in the water-based ink composition. The aqueous ink composition according to [1], wherein the mass ratio represented by the aqueous urethane resin (A1) / aqueous urethane resin (A2) is 0.08 to 0.7. The aqueous ink composition according to [1] or [2], further containing wax. The aqueous ink composition according to any one of [1] to [3], further containing a pigment. The aqueous ink composition according to [4], wherein the pigment in the aqueous ink composition is one kind. For the aqueous ink composition obtained by mixing and adjusting a plurality of the aqueous ink compositions having different color tones, the difference between the viscosity at 25°C measured by Zahn cup #4 and the viscosity after the adjusted aqueous ink composition is allowed to stand at 25°C for one week is less than ±3 seconds. The aqueous ink composition according to any one of [1] to [5]. The aqueous ink composition according to any one of [1] to [6], further containing a curing agent. The aqueous ink composition according to any one of [1] to [7], which is for gravure printing or flexographic printing. [9] An aqueous ink set including a plurality of aqueous ink compositions having different color tones, wherein each of the plurality of aqueous ink compositions contains an aqueous urethane resin and an aqueous medium, and at least a part of the plurality of aqueous ink compositions further contains a pigment, In each of the plurality of aqueous ink compositions, the aqueous urethane resin contains an aqueous urethane resin (A1) and an aqueous urethane resin (A2), the aqueous urethane resin (A1) is an ether-based urethane resin having a glass transition temperature of -70 to -30°C, the aqueous urethane resin (A2) is an ester-based urethane resin having a glass transition temperature of 60 to 120°C, and the total content of the aqueous urethane resin (A1) and the aqueous urethane resin (A2) is 20 to 94% by mass with respect to the total mass of the non-volatile components in the aqueous ink composition. An aqueous ink set. The aqueous ink set according to [9], wherein in each of the plurality of aqueous ink compositions, the mass ratio represented by the aqueous urethane resin (A1) / aqueous urethane resin (A2) is 0.08 to 0.7.

[11] The aqueous ink set according to [9] or

[10] , wherein each of the plurality of aqueous ink compositions further contains wax.

[12] The aqueous ink set according to any one of [9] to

[11] , wherein the pigment in the aqueous ink composition containing the pigment is one kind.

[13] For the aqueous ink composition obtained by mixing and color - adjusting at least two of the plurality of aqueous ink compositions, the difference between the viscosity measured at 25 °C with a Zahn cup #4 and the viscosity after the color - adjusted aqueous ink composition is allowed to stand at 25 °C for one week is less than ±3 seconds. The aqueous ink set according to any one of [9] to

[12] .

[14] The aqueous ink set according to any one of [9] to

[13] , further comprising a curing agent.

[15] The aqueous ink set according to any one of [9] to

[14] , which is for gravure printing or flexographic printing.

[16] Comprising a plastic film and an ink layer provided on the plastic film, An ink - layer - attached film, wherein the ink layer is an ink layer formed from the aqueous ink composition according to any one of [1] to [8].

[17] A method for manufacturing an ink - layer - attached film, wherein printing is performed on a plastic film using the aqueous ink composition according to any one of [1] to [8] to form an ink layer.

[18] A method for manufacturing an ink - layer - attached film, wherein printing is performed on a plastic film using as it is at least one of the plurality of aqueous ink compositions provided in the aqueous ink set according to any one of [9] to

[15] to form an ink layer.

[19] Prepare an aqueous ink composition obtained by mixing and color - adjusting at least two of the plurality of aqueous ink compositions provided in the aqueous ink set according to any one of [9] to

[15] , A method for manufacturing an ink - layer - attached film, wherein printing is performed on a plastic film using the color - adjusted aqueous ink composition to form an ink layer. A laminate film comprising the film with an ink layer described in

[20]

[16] , an adhesive layer provided on the ink layer of the film with an ink layer, and a resin layer provided on the adhesive layer. A packaging material comprising the laminate film described in

[21]

[20] .

Effects of the Invention

[0009] According to the present invention, it is possible to provide an aqueous ink composition and an aqueous ink set excellent in alcohol dilutability and ink fluidity, an ink layer-containing film using the aqueous ink composition, a method for producing the same, a laminate film, and a packaging material.

Modes for Carrying Out the Invention

[0010] Hereinafter, the present invention will be described in detail. The following embodiments are merely illustrative for explaining the present invention, and it is not intended to limit the present invention only to these embodiments. The present invention can be implemented in various modes without departing from its gist. In the present invention, "aqueous" in the aqueous ink means containing an aqueous medium. "Aqueous medium" means a liquid medium containing water. "Liquid medium" means a volatile liquid such as water and an organic solvent. "Aqueous urethane resin" is a general term for "water-soluble urethane resin" and "water-dispersible urethane resin (urethane resin emulsion, urethane resin dispersion)". The content of the aqueous urethane resin in this specification is all in terms of non-volatile content. The "non-volatile content" of the ink composition refers to the components contained in the ink composition excluding the liquid medium, and is the component that will finally form the ink layer, and specifically, it is measured in accordance with JIS K 5601-1-2:2008. The same applies to the non-volatile content of the aqueous urethane resin. In this specification, the "coating film" refers to the coating film formed by the aqueous ink composition of the present invention.

[0011] The glass transition temperature of the aqueous urethane resin is measured in accordance with JIS K 7121 as follows. Using a differential scanning calorimeter, the glass transition temperature is determined from the intersection of the baseline and the tangent of the endothermic curve in the curve (DSC curve) obtained by heating 10 mg of the aqueous urethane resin from -100 °C to 160 °C at a rate of 20 °C / min.

[0012] [Aqueous Ink Composition] The aqueous ink composition according to one embodiment of the present invention contains an aqueous urethane resin and an aqueous medium. The aqueous ink composition may further contain an alkalinity-imparting agent. The aqueous ink composition may further contain wax. The aqueous ink composition may further contain a pigment. When the aqueous ink composition is a medium mainly used for concentration adjustment, it typically does not contain a pigment. The aqueous ink composition may further contain a curing agent. The aqueous ink composition may further contain other components other than the aqueous urethane resin, the aqueous medium, the alkalinity-imparting agent, the wax, the pigment, and the curing agent.

[0013] [Aqueous Urethane Resin] The aqueous urethane resin is a binder component. From the viewpoints of alcohol dilutability, pigment dispersibility, and ink fluidity, the aqueous urethane resin contains an aqueous urethane resin (A1) and an aqueous urethane resin (A2).

[0014] [Aqueous Urethane Resin (A1)] The aqueous urethane resin (A1) is an ether-based urethane resin having a glass transition temperature of -70 to -30 °C. By containing the aqueous urethane resin (A1) in the aqueous ink composition, the pigment dispersibility and the ink fluidity are good, and the adhesion to the base film and the laminate strength are improved.

[0015] When the glass transition temperature of the aqueous urethane resin (A1) is -70°C or higher, it has excellent blocking resistance. When the glass transition temperature of the aqueous urethane resin (A1) is -30°C or lower, it has excellent adhesion to the base film of the coating film, laminate strength, pigment dispersibility, and ink fluidity. The glass transition temperature of the aqueous urethane resin (A1) is preferably -70 to -30°C, more preferably -65 to -32°C, and particularly preferably -60 to -35°C.

[0016] The ether-based urethane resin is a urethane resin having an ether bond in the main chain. Examples of the ether-based urethane resin include reaction products of polyvalent isocyanate compounds and polyether polyol compounds. The polyvalent isocyanate compound is an organic compound having at least two isocyanate groups in the molecule. The polyether polyol compound is an organic compound having an ether bond in the molecule and at least two hydroxyl groups.

[0017] Examples of the polyvalent isocyanate compound include aliphatic, alicyclic, aromatic polyvalent isocyanate compounds, etc. Specific examples of the polyvalent isocyanate compound include aliphatic diisocyanates such as trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, 2,6-diisocyanate methyl caproate; alicyclic diisocyanates such as hydrogenated diphenylmethane diisocyanate, isophorone diisocyanate, norbornene diisocyanate, 1,3-cyclopentane diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate), 4,4'-methylenebis(cyclohexyl isocyanate), methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 1,4-bis(isocyanate methyl)cyclohexane, 1,3-bis(isocyanate methyl)cyclohexane; aromatic diisocyanates such as m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4- or 2,6-tolylene diisocyanate, 4,4'-toluidine diisocyanate, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate; multimerized polyvalent isocyanate compounds having an allophanate structure, a nurate structure, a biuret structure, etc. using the above diisocyanates; triisocyanates such as 1,3,5-triisocyanate benzene, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate hexane; polyisocyanates such as 4,4'-diphenyl dimethylmethane-2,2'-5,5'-tetraisocyanate. These polyvalent isocyanate compounds may be used alone or in combination of two or more kinds.

[0018] Examples of the polyether polyol compound include polyether polyols obtained by polymerizing oxirane compounds such as ethylene oxide, propylene oxide, butylene oxide, and tetrahydrofuran using low molecular weight polyols such as ethylene glycol, propylene glycol, trimethylolpropane, and glycerin as initiators. These polyol compounds may be used alone or in combination of two or more.

[0019] The aqueous urethane resin (A1) can be obtained, for example, by reacting a polyvalent isocyanate compound and a polyether polyol compound by a known method. If necessary, a chain extender such as a polyamine or a polyol, or a reaction terminator such as a monoamine may be used in the reaction. Further, a hydrolyzable silicon group-containing compound may be reacted with the reaction product to introduce a silanol group.

[0020] As the aqueous urethane resin (A1), commercially available products may be used. Examples of commercially available products include "Urianol W" manufactured by Arakawa Chemical Industries, Ltd.; "Evafanol HA" manufactured by Nichiwa Chemical Co., Ltd.; "NeoRez" manufactured by Covestro, etc. The aqueous urethane resin (A1) may be used alone or in combination of two or more.

[0021] [Aqueous urethane resin (A2)] The aqueous urethane resin (A2) is an ester-based urethane resin having a glass transition temperature of 60 to 120°C. When the aqueous ink composition contains the aqueous urethane resin (A2), the alcohol dilutability is good and the boilability is improved.

[0022] When the glass transition temperature of the aqueous urethane resin (A2) is 60°C or higher, the blocking resistance and boilability are excellent. When the glass transition temperature of the aqueous urethane resin (A2) is 120°C or lower, the adhesion to the base film of the coating film, the laminating strength, and the boilability are excellent. The glass transition temperature of the aqueous urethane resin (A2) is preferably from 60 to 120°C, more preferably from 62 to 118°C, and particularly preferably from 65 to 116°C.

[0023] The ester urethane resin is a urethane resin having an ester bond in the main chain. Examples of the ester urethane resin include reaction products of a polyisocyanate compound and a polyester polyol compound. The polyisocyanate compound is an organic compound having at least two isocyanate groups in the molecule as described above. The polyester polyol compound is an organic compound having an ester bond in the molecule and at least two hydroxyl groups.

[0024] Examples of the polyisocyanate compound include the same ones as described above.

[0025] Examples of the polyester polyol compound include saturated or unsaturated glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, pentanediol, 3-methyl-1,5-pentanediol, octanediol, 1,9-nonanediol, 1,8-nonanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, bisphenol A, and hydrogenated bisphenol A; polyester polyols obtained by dehydration condensation of dibasic acids such as adipic acid, maleic acid, fumaric acid, phthalic anhydride, isophthalic acid, terephthalic acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, azelaic acid, sebacic acid, suberic acid or acid anhydrides or dimer acids corresponding thereto; and polyether ester polyols obtained by reacting the dibasic acids or their dialkyl esters with the polyether polyols. These polyol compounds may be used alone or in combination of two or more.

[0026] The aqueous urethane resin (A2) can be obtained, for example, by reacting a polyvalent isocyanate compound and a polyester polyol compound by a known method. If necessary, a chain extender such as a polyamine or a polyol, or a reaction terminator such as a monoamine may be used in the reaction. Further, a hydrolyzable silicon group-containing compound may be reacted with the reaction product to introduce a silanol group.

[0027] As the aqueous urethane resin (A2), a commercially available product may be used. Examples of commercially available products include "Takelac W", "Takelac WS" manufactured by Mitsui Chemicals, Inc., and "NeoRez" manufactured by Covestro. The aqueous urethane resin (A2) may be used alone or in combination of two or more.

[0028] The total content of the aqueous urethane resin (A1) and the aqueous urethane resin (A2) is 20 to 94% by mass, preferably 21 to 93.7% by mass, and more preferably 22 to 93.5% by mass with respect to the total mass of the non-volatile components in the aqueous ink composition. When the total content of the aqueous urethane resin (A1) and the aqueous urethane resin (A2) is at least the above lower limit value, the adhesion to the base film of the coating film, the pigment dispersibility, the ink fluidity, the storage stability of the ink, and the printing suitability are excellent. When the total content of the aqueous urethane resin (A1) and the aqueous urethane resin (A2) is at most the above upper limit value, the ink fluidity and the alcohol dilutability are excellent.

[0029] The total content of the aqueous urethane resin (A1) and the aqueous urethane resin (A2) is preferably 7.5 to 29% by mass, more preferably 9 to 27% by mass, and further preferably 11 to 25% by mass with respect to the total mass of the ink composition. When the total content of the aqueous urethane resin (A1) and the aqueous urethane resin (A2) is at least the above lower limit value, the adhesion to the base film of the coating film, the pigment dispersibility, the ink fluidity, the storage stability of the ink, and the printing suitability are more excellent. When the total content of the aqueous urethane resin (A1) and the aqueous urethane resin (A2) exceeds the above upper limit value, the ink fluidity and the alcohol dilutability are more excellent.

[0030] The ratio of the mass of the aqueous urethane resin (A1) to the mass of the aqueous urethane resin (A2), that is, the mass ratio represented by aqueous urethane resin (A1) / aqueous urethane resin (A2) (hereinafter, also referred to as "(A1) / (A2)"), is preferably 0.05 to 0.8, more preferably 0.08 to 0.7, and even more preferably 0.1 to 0.6 in terms of nonvolatile content. When (A1) / (A2) is at least the above lower limit, the pigment dispersibility and ink fluidity are more excellent. When (A1) / (A2) is at most the above upper limit, the alcohol dilutability is more excellent.

[0031] The aqueous urethane resin may further contain other aqueous urethane resins other than the aqueous urethane resin (A1) and the aqueous urethane resin (A2). Examples of the other aqueous urethane resins include reaction products of polyvalent isocyanate compounds and polyol compounds other than polyether polyol compounds and polyester polyol compounds.

[0032] Examples of the other polyol compounds include polyolefin polyols such as polyethylene polyol and polypropylene polyol; and polycarbonate polyols obtained by reacting the glycols with methyl carbonate, diphenyl carbonate, ethylene carbonate, phosgene, etc. These polyol compounds may be used alone or in combination of two or more.

[0033] <aqueous medium> Examples of the aqueous medium include water; and mixed solvents of water and organic solvents. The organic solvent is not particularly limited as long as it is soluble in water. Examples thereof include alcohol solvents such as methanol, ethanol, n-propanol, i-propanol, n-butanol, and i-butanol; ketone solvents such as acetone; and glycol ether solvents such as propylene glycol monomethyl ether. These organic solvents may be used alone or in combination of two or more.

[0034] The content of the aqueous medium is preferably 20 to 85% by mass, more preferably 30 to 80% by mass, and even more preferably 35 to 75% by mass with respect to the total mass of the aqueous ink composition. When the content of the aqueous medium is at least the above lower limit value, the ink fluidity is more excellent. When the content of the aqueous medium is at most the above upper limit value, the drying property is more excellent.

[0035] <Alkalinity imparting agent> The alkalinity imparting agent is a compound that maintains the pH of the aqueous ink within an appropriate range. By maintaining the pH of the aqueous ink within an appropriate range, the redissolubility of the ink can be maintained. Examples of the alkalinity imparting agent include ammonia; organic amines such as morpholine, N,N-dimethylaminoethanol, N-methylmorpholine, 2-amino-2-methyl-1-propanol, ethylenediamine, triethylenediamine, triethylamine, tripropylamine, and tributylamine; and alkali metal salts such as sodium hydroxide and potassium hydroxide. These alkalinity imparting agents may be used alone or in combination of two or more.

[0036] As the alkalinity imparting agent, commercially available products may be used. Examples of the commercially available products include products named "AMP-90" and "DMAMP-80" manufactured by ANGUS; and products named "Amino Alcohol PA", "Amino Alcohol 2FA", and "Amino Alcohol 2Mabs" manufactured by Nippon Emulsion Co., Ltd. These may be used alone or in combination of two or more.

[0037] The content of the alkalinity imparting agent is preferably 0.1 to 5% by mass, more preferably 0.1 to 4% by mass, and even more preferably 0.1 to 3% by mass with respect to the total mass of the aqueous ink composition. When the content of the alkalinity imparting agent is at least the above lower limit value, the pH in the ink composition can be maintained within an acceptable range, and the redissolubility of the ink is more excellent. When the content of the alkalinity imparting agent is at most the above upper limit value, the printing suitability is more excellent.

[0038] The pH of the aqueous ink composition is preferably from 7 to 11, more preferably from 7.5 to 11, and even more preferably from 8 to 11. When the pH in the aqueous ink composition is at or above the above lower limit value, the storage stability of the aqueous ink composition is more excellent. When the pH in the aqueous ink composition is at or below the above upper limit value, the working safety is more excellent.

[0039] <Wax> Wax is used to improve the abrasion resistance of the ink layer. As the wax, an aqueous wax is preferable. An aqueous wax is a wax dispersed in water to form an emulsion or dispersion. The wax dispersed in water may be a conventionally known wax, and examples thereof include polyethylene wax, polypropylene wax, modified paraffin wax, carnauba wax, and polytetrafluoroethylene wax. These aqueous waxes may be used alone or in combination of two or more.

[0040] The average particle diameter of the dispersed particles in the aqueous wax is preferably from 0.1 to 10 μm, more preferably from 1 to 7 μm, and even more preferably from 1 to 5 μm. When the average particle diameter is at or above the above lower limit value, the abrasion resistance is more excellent. When the average particle diameter is at or below the above upper limit value, the color development property and the laminating strength are more excellent. The average particle diameter of the dispersed particles in the aqueous wax is determined by the Coulter counter method.

[0041] The penetration of the wax is preferably from 0.1 to 12, more preferably from 0.1 to 11, and even more preferably from 0.1 to 10. When the penetration of the wax is at or below the above upper limit value, the blocking resistance is more excellent. The penetration of the wax is determined in accordance with JIS K 2207.

[0042] When the aqueous ink composition contains wax, the content of the wax in terms of non-volatile matter is preferably 0 to 10% by mass, more preferably 0.5 to 8% by mass, and even more preferably 1 to 6% by mass with respect to the total mass of the aqueous ink composition. When the content of the wax is at least the above lower limit value, the abrasion resistance is more excellent. When the content of the wax is at most the above upper limit value, the color development property and the laminate strength are more excellent.

[0043] <Pigment> The pigment may be a pigment known as a colorant, and examples thereof include organic pigments and inorganic pigments. Examples of the organic pigment include azo pigments such as monoazo and condensed azo; threne pigments such as anthraquinone, perinone, perylene, and thioindigo; phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green; quinacridone pigments; dioxazine pigments; isoindolinone pigments; pyrrolopyrrole pigments; aniline black; and organic fluorescent pigments. Examples of the inorganic pigment include natural products such as clay, barite, mica, and talc; ferrocyanides such as ultramarine, sulfides such as zinc sulfide; sulfates such as barium sulfate; oxides such as chromium oxide, zinc white, titanium oxide, and iron oxide; hydroxides such as aluminum hydroxide; silicates such as calcium silicate and ultramarine; carbonates such as calcium carbonate and magnesium carbonate; carbon such as carbon black and graphite; metal powders such as aluminum powder, bronze powder, and zinc powder; and fired pigments. These pigments may be used alone or in combination of two or more.

[0044] When the aqueous ink composition contains a pigment, it is preferable that the pigment in the aqueous ink composition is one kind. When the pigment in the aqueous ink composition is one kind, a coating film with higher chroma and good appearance can be formed regardless of the presence or absence of color adjustment.

[0045] The content of the pigment is preferably 1 to 50% by mass, more preferably 1 to 48% by mass, and even more preferably 1 to 45% by mass with respect to the total mass of the aqueous ink composition. When the content of the pigment is at least the above lower limit value, the hiding power and color development property are more excellent. When the content of the pigment is at most the above upper limit value, the adhesion to the base film of the coating film and the ink fluidity are more excellent.

[0046] <Hardener> The hardener is used as needed to further improve the laminating strength and the adhesion to the base film.

[0047] As the hardener, known ones can be used. For example, isocyanate-based hardeners, blocked isocyanate-based hardeners, carbodiimide-based hardeners, oxazoline-based hardeners, epoxy-based hardeners, aziridine-based hardeners, etc. can be mentioned. Among these, from the viewpoint of further improving the laminating strength and the adhesion to the base film, isocyanate-based hardeners, carbodiimide-based hardeners, epoxy-based hardeners, and aziridine-based hardeners are preferable. These hardeners may be used alone or in combination of two or more.

[0048] The isocyanate-based curing agent is a compound containing two or more isocyanate groups in one molecule. As the isocyanate-based curing agent, commercially available products may be used. Examples of commercially available products include product names "Takenate WD-720", "Takenate WD-725", "Takenate WD-726", "Takenate WD-730", "Takenate WD-220", "Takenate XWD-HS7", "Takenate XWD-HS30" manufactured by Mitsui Chemicals, Inc.; product names "Aquate 100", "Aquate 110", "Aquate 200", "Aquate 210" manufactured by Nippon Polyurethane Industry Co., Ltd.; product names "Duranate WB40-100", "Duranate WB40-80D", "Duranate WT20-100", "Duranate WT30-100", "Duranate WL70-100", "Duranate WR80-70P", "Duranate WE50-100" manufactured by Asahi Kasei Corporation; product names "Bayhydur 3100", "Bayhydur 302", "Bayhydur 304", "Bayhydur 305", "Bayhydur XP2451 / 1", "Bayhydur XP2487 / 1", "Bayhydur XP2547", "Bayhydur XP2655", "Bayhydur XP2700" manufactured by Bayer MaterialScience; product names "Basonat HW100", "Basonat HA100", "Basonat HW1180PC" manufactured by BASF. These isocyanate-based curing agents may be used alone or in combination of two or more kinds.

[0049] The blocked isocyanate-based curing agent is a compound containing two or more blocked isocyanate groups in one molecule. Examples of the blocked isocyanate-based curing agent include blocked products with blocking agents for isocyanate-based curing agents (for example, alcohol-based compounds, phenol-based compounds, oxime-based compounds, lactam-based compounds, pyrazole-based compounds, and active methylene compounds, etc.). These blocked isocyanate-based curing agents may be used alone or in combination of two or more kinds.

[0050] A carbodiimide-based curing agent is a compound containing two or more carbodiimide groups in one molecule. Examples of carbodiimide-based curing agents include poly(4,4'-diphenylmethane carbodiimide), poly(dicyclohexylmethane carbodiimide), and poly(diisopropylcarbodiimide). Examples of commercially available carbodiimide-based curing agents include the "Carbodilite" series manufactured by Nisshinbo Chemicals Co., Ltd. These carbodiimide-based curing agents may be used alone or in combination of two or more kinds.

[0051] An oxazoline-based curing agent is a compound containing two or more oxazoline groups in one molecule. Specific examples of oxazoline-based curing agents include polyvalent oxazolines such as 2,2'-bis-(2-oxazoline), 2,2'-methylene-bis-(2-oxazoline), 2,2'-(1,4-phenylene)-bis(2-oxazoline), and polymers or copolymers having monomer units containing an oxazoline group such as 2-vinyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, and 2-isopropenyl-5-ethyl-2-oxazoline. The oxazoline group-containing monomers may be used alone or in combination of two or more kinds. Further, a copolymer of an oxazoline group-containing monomer and another monomer copolymerizable with this monomer may also be used. Examples of commercially available oxazoline-based curing agents include the "Epocros" series manufactured by Nippon Shokubai Co., Ltd. These oxazoline-based curing agents may be used alone or in combination of two or more kinds.

[0052] Epoxy curing agents are compounds containing two or more epoxy groups in one molecule. Examples of epoxy curing agents include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, triglycidyl aminophenol, biphenyl diglycidyl ether, triglycidyl isocyanurate, polyglycidyl (meth)acrylate, and copolymers of glycidyl (meth)acrylate and vinyl monomers copolymerizable therewith. Examples of commercially available epoxy curing agents include the "jER" series of product names manufactured by Mitsubishi Chemical Corporation and the "Denacol EX" series of product names manufactured by Nagase ChemteX Corporation. These epoxy curing agents may be used alone or in combination of two or more.

[0053] Aziridine curing agents are compounds containing two or more aziridine groups in one molecule. Examples of aziridine curing agents include 2,2-bishydroxymethylbutanol-tris[3-(1-aziridinyl)propionate] and 4,4'-bis(ethyleneiminocarbonylamino)diphenylmethane. Examples of commercially available aziridine curing agents include the "Chemite" series of product names manufactured by Nippon Shokubai Co., Ltd. These aziridine curing agents may be used alone or in combination of two or more.

[0054] When the aqueous ink composition contains a curing agent, the content in terms of the non-volatile content of the curing agent is preferably 0.1 to 15% by mass, more preferably 0.3 to 12% by mass, and even more preferably 0.5 to 10% by mass with respect to the total mass of the aqueous ink composition. When the content of the curing agent is at least the above lower limit, the laminating strength and the adhesion to the base film are more excellent. When the content of the curing agent is at most the above upper limit, the storage stability and the ink fluidity are more excellent.

[0055] <Other components> Examples of other components include anti-settling agents, ultraviolet absorbers, antioxidants, leveling agents, thickeners, defoamers, lubricants, dispersants, stabilizers, and the like. These other components may be used alone or in combination of two or more.

[0056] The content of other components is not particularly limited as long as it does not impair the effects of the present invention. For example, it is preferably 0 to 20% by mass, more preferably 0 to 15% by mass, and even more preferably 0 to 10% by mass based on the total mass of the aqueous ink composition. When the aqueous ink composition contains other components, the content of the other components is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.5% by mass or more based on the total mass of the aqueous ink composition. If the content of the other components is at least the above lower limit value, the effects of the other components will be sufficiently exhibited.

[0057] <Manufacturing method> The aqueous ink composition of the present embodiment can be obtained, for example, by dissolving or dispersing an aqueous urethane resin and, if necessary, any one or more of an alkalinity-imparting agent, wax, pigment, curing agent, and other components in an aqueous medium. The mixing method of each component is not particularly limited, and each component can be mixed by various methods. The method of dissolving or dispersing each component in an aqueous medium is not particularly limited, and it can be carried out using a known disperser. Examples of the disperser include a paint shaker, ball mill, attritor, sand mill, bead mill, dynomill, roll mill, ultrasonic mill, high-pressure collision disperser, etc. At this time, one type of disperser may be used for one or more dispersion treatments, or two or more types of dispersers may be used in combination for a plurality of dispersion treatments. The aqueous ink composition of the present embodiment may be prepared by mixing at least two of the plurality of aqueous ink compositions provided in the aqueous ink set described later.

[0058] <Use> The aqueous ink composition of the present embodiment is typically printed on an arbitrary substrate to form an ink layer. Examples of the substrate include a plastic film. An ink layer-equipped film including a plastic film and an ink layer provided on the plastic film is suitable, for example, for flexible packaging. Here, the "flexible packaging" refers to a packaging material composed of a flexible material, that is, a flexible package, which is used for packaging foods, daily necessities, etc.

[0059] Examples of the plastic film include plastic films (base films) such as polyolefin (e.g., polyethylene (PE), polypropylene (PP), etc.), polyester (e.g., polyethylene terephthalate (PET), etc.), polystyrene (PS), oriented polypropylene (OPP), polyamide (NY), etc. These plastic films may be used alone or two or more of them may be laminated and used.

[0060] The printing method may be a known printing method. When the aqueous ink composition of this embodiment is used for dilution with a diluting medium containing alcohol having a drying speed faster than that of water at a high ratio, high dilution rate and low viscosity can be achieved, and it is suitable for gravure printing or flexographic printing because of its excellent high-speed printing suitability.

[0061] Prior to printing, the aqueous ink composition may be diluted with a diluting medium containing alcohol. By diluting with a diluting medium containing alcohol, the drying speed can be increased, the blocking resistance can be improved, and the leveling property can be improved by reducing the surface tension. Examples of the alcohol used for the diluting medium include methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, etc. These alcohols may be used alone or two or more of them may be used in combination. The diluting medium may contain water. The amount of the diluting medium can be appropriately set according to the printing method so that the viscosity of the aqueous ink composition after dilution becomes a viscosity suitable for printing. For example, in the case of gravure printing, the viscosity of the aqueous ink composition after dilution is preferably 13.5 to 18 seconds as the viscosity at 25°C measured using a Zahn cup #3. In the case of flexographic printing, the viscosity of the aqueous ink composition after dilution is preferably 14 to 20 seconds as the viscosity at 25°C measured using a Zahn cup #4.

[0062] By performing printing on a plastic film using the aqueous ink composition of the present embodiment, a film with an ink layer can be obtained. Furthermore, by providing an adhesive layer on the ink layer of the film with an ink layer and laminating a resin layer on the adhesive layer, a laminated film can be obtained.

[0063] Examples of the laminating process preferably include an extrusion lamination method, a dry lamination method, a non-solvent lamination method, etc. In the extrusion lamination method, after coating an anchor coat agent on the ink layer of the film with an ink layer or without coating, a molten polyethylene resin, a molten polypropylene resin, etc. are extruded and laminated. In the dry lamination method, an adhesive diluted to an appropriate viscosity with an organic solvent is coated and dried on the ink layer of the film with an ink layer, and then heat-pressed and laminated with a sealant film (resin layer). In the non-solvent lamination method, a solvent-free adhesive is coated on the ink layer of the film with an ink layer, and then heat-pressed and laminated with a sealant film.

[0064] The laminated film can be used as a packaging material for flexible packaging as it is or by processing it into a form such as a bag shape by heat sealing or the like. By packaging an object to be packaged such as food or daily necessities with the packaging material, a packaged body can be obtained.

[0065] <Function and Effect> Since the aqueous ink composition of the present embodiment described above contains the aqueous urethane resin (A1) and the aqueous urethane resin (A2), it is excellent in alcohol dilutability and ink fluidity.

[0066] The aqueous ink composition of the present embodiment also has good pigment dispersibility. When the pigment dispersibility of the aqueous ink composition is good, the color developability of the ink layer formed from the aqueous ink composition becomes good.

[0067] The aqueous ink composition of the present embodiment also has good color adjustment stability. When actually printing ink, in order to adjust the color tone, a process called color adjustment is generally performed, in which inks of a plurality of colors and a transparent ink (medium) containing no pigment are appropriately mixed, and then used for printing. Therefore, inks are required to have good color adjustment stability so that problems such as thickening of the ink, hue separation, sedimentation due to shock, and appearance defects do not easily occur when color adjustment is performed.

[0068] For the aqueous ink composition of the present embodiment, the difference between the viscosity at 25°C measured with a Zahn cup #4 for a mixture of a plurality of aqueous ink compositions of the present embodiment having different color tones from each other (hereinafter also referred to as "color-adjusted aqueous ink composition") and the viscosity measured in the same manner after allowing the color-adjusted aqueous ink composition to stand at 25°C for 1 week is preferably less than ±3 seconds, and more preferably less than ±2 seconds. The smaller this viscosity difference is, the better the color adjustment stability. Examples of methods for reducing this viscosity difference include using a common binder resin for the plurality of aqueous ink compositions to be mixed.

[0069] According to the aqueous ink composition of the present embodiment, an ink layer-coated film excellent in adhesion between the ink layer and the plastic film, and a laminated film excellent in lamination strength and boil suitability can be obtained. In the case of flexible packaging applications, a package obtained by packaging food or the like with a packaging material may be boiled for purposes such as sterilization. If the boil suitability is low, there is a risk of delamination (lamination floating) during boiling.

[0070] [Water-based ink set] The water-based ink set according to one embodiment of the present invention includes a plurality of water-based ink compositions having different color tones from each other. Each of the water-based ink compositions is a water-based ink composition of the present embodiment and contains a water-based urethane resin and a water-based medium. At least a part of the water-based ink composition further contains a pigment. One of the water-based ink compositions may be a so-called medium that does not contain a pigment. Each of the water-based ink compositions may further contain an alkalinity-imparting agent. Each of the water-based ink compositions may further contain wax. Each of the water-based ink compositions may further contain other components other than the water-based urethane resin, the water-based medium, the alkalinity-imparting agent, the wax, the pigment, and the curing agent. The water-based ink set may further include a curing agent.

[0071] The water-based urethane resin, the water-based medium, the pigment, the alkalinity-imparting agent, the wax, the other components, and the curing agent are each the same as described above, and the preferred contents are also the same as described above.

[0072] The water-based ink set of the present embodiment can be used for the same applications as the water-based ink composition of the present embodiment. In printing, at least one of the plurality of water-based ink compositions constituting the water-based ink set may be directly used for printing, or at least two of the plurality of water-based ink compositions may be mixed and adjusted in color and then used for printing, or both of them may be used for printing.

Examples

[0073] Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. "% " means "% by mass" unless otherwise specified.

[0074] [Raw materials used] <Waterborne urethane resin (A1)> · A1-1: Ether-based urethane resin (manufactured by Arakawa Chemical Industries, Ltd., trade name "Yuriano W", glass transition temperature: -50°C, viscosity: 30 - 1000 mPa·s / 25°C). · A1-2: Ether-based urethane resin (manufactured by Nihon Kayaku Co., Ltd., trade name "Evafanol HA", glass transition temperature: -40°C, viscosity: less than 500 mPa·s / 25°C). · A1-3: Ether-based urethane resin (manufactured by Mitsui Chemicals, Inc., trade name "Takelac W", glass transition temperature: 25°C, viscosity: 50 mPa·s / 25°C). · A1-4: Ether-based urethane resin (manufactured by Mitsui Chemicals, Inc., trade name "Takelac WS", glass transition temperature: 70°C, viscosity: 17 mPa·s / 25°C).

[0075] <Waterborne urethane resin (A2)> · A2-1: Ester-based urethane resin (manufactured by Mitsui Chemicals, Inc., trade name "Takelac WS", glass transition temperature: 70°C, viscosity: 200 mPa·s / 25°C). · A2-2: Ester-based urethane resin (manufactured by Mitsui Chemicals, Inc., trade name "Takelac WS", glass transition temperature: 115°C, viscosity: 30 mPa·s / 25°C). · A2-3: Ester-based urethane resin (manufactured by Mitsui Chemicals, Inc., trade name "Takelac WS", glass transition temperature: 50°C, viscosity: 20 mPa·s / 25°C). · A2-4: Carbonate-based urethane resin (manufactured by Mitsui Chemicals, Inc., trade name "Takelac WS", glass transition temperature: 120°C, viscosity: 20 mPa·s / 25°C). Comparative product.

[0076] <Aqueous medium> · IPA: i-Propanol. · Water: Tap water.

[0077] <Alkalinity imparting agent> · B-1: 25% aqueous ammonia.

[0078] <Wax> · C-1: Polyethylene wax (manufactured by Mitsui Chemicals, Inc., trade name "Chemipar Pearl W-500", solid content 40%, particle size: 2.5 μm, penetration: 10).

[0079] <Pigment> · D-1: Pigment White 6 (manufactured by Sakai Chemical Industry Co., Ltd., trade name "Titane R-21"). · D-2: Pigment Red 48:1 (manufactured by Toyo Color Co., Ltd., trade name "Leonol Red TT-4804G"). · D-3: Pigment Red 48:3 (manufactured by Toyo Color Co., Ltd., trade name "Leonol Red TT-4803"). · D-4: Pigment Yellow 83 (manufactured by BASF Japan Ltd., trade name "Irgallite Yellow D1745"). · D-5: Pigment Yellow 14 (manufactured by BASF Japan Ltd., trade name "Irgallite Yellow D2175"). · D-6: Pigment Blue 15:3 (manufactured by BASF Japan Ltd., trade name "Helio Gen Blue D7092"). · D-7: Pigment Blue 15:4 (manufactured by Toyo Color Co., Ltd., trade name "Leonol Blue 7390). · D-8: Pigment Blue 15:3 (manufactured by BASF Japan Ltd., trade name "Helio Gen Blue D7088"). · D-9: Pigment Blue 15:3 (manufactured by BASF Japan Ltd., trade name "Helio Gen Blue D7086"). · D-10: Pigment Green 7 (manufactured by Toyo Color Co., Ltd., trade name "Leonol Green 8948"). · D-11: Pigment Black 7 (manufactured by CABOT, trade name "Regal 330"). · D-12: Pigment Red 101 (manufactured by LANXESS, trade name "Bayferrox 4100"). · D-13: Pigment Red 146 (manufactured by Toyo Color Co., Ltd., trade name "Leonol Red 5620"). · D-14: Pigment Orange 13 (manufactured by DIC Corporation, trade name "Pigment Orange G"). · D-15: Pigment Red 122 (manufactured by BASF Japan Ltd., trade name "Sinkashapink D4450"). · D-16: Pigment Violet 23 (manufactured by Toyo Color Co., Ltd., trade name "Leonogen Violet FG-6150"). · D-17: Aluminum paste (manufactured by Toyo Aluminum Co., Ltd., trade name "Aluminum Paste WJP-T95F"). · D-18: Pearl pigment, Pigment White 6 / Pigment White 20 (manufactured by MERCK KGaA, trade name "Iriodin 6103 Ice White").

[0080] <Other optional components> · Defoaming agent: manufactured by BYK, trade name "BYK-028". · Curing agent: carbodiimide-based curing agent (manufactured by Nisshinbo Chemical Inc., trade name "Carbodilite E-05", solid content 40%).

[0081] [Examples 1 to 28, Comparative Examples 1 to 16] <Preparation of aqueous ink composition> According to the compositions shown in Tables 1 to 9, an aqueous urethane resin (A), an alkalinity-imparting agent (B), a wax (C), a pigment (D), and other optional components were mixed, and dispersion treatment was performed using a dynomill (using glass beads). The obtained mixture was dispersed in an aqueous medium (E) under the condition of 1000 rpm using an inverter-type stirrer to obtain an aqueous ink composition. In Tables 1 to 9, the content of each component is the ratio (%) with respect to the total mass of the aqueous ink composition. The "balance" of water is the amount such that the total mass of the aqueous ink composition is 100%.

[0082] For the obtained aqueous ink composition, a gravure printing film, a flexographic printing film, or a laminate film was produced according to the following procedure, and the alcohol dilutability, ink fluidity, color development property, adhesion, laminate strength, and boil resistance were evaluated. In Tables 1 to 9, in the examples where "gravure" is described in the printing method column, a gravure printing film was produced, and in the examples where "flexo" is described, a flexographic printing film was produced. The evaluation results are shown in Tables 1 to 9.

[0083] <Production of Gravure Printing Film> The prepared aqueous ink composition was diluted with a diluting solvent (methanol / IPA = 8 / 2 (mass ratio)) so that the viscosity at 25°C measured using a Zahn cup #3 was 15 seconds to prepare an ink for printing. Using a gravure printing machine (manufactured by Matsuo Sangyo Co., Ltd., trade name "K Printing Proofer") equipped with a Heliotype 175 line / inch gravure engraving plate, the prepared printing ink was applied to the treated surface of a single-sided treated PET film (manufactured by Toyobo Co., Ltd., trade name "Ester Film 8102") with a thickness of 12 μm, and then dried at 25°C for 24 hours to produce a gravure printing film.

[0084] <Production of Flexographic Printing Film> Each prepared ink composition was diluted with water so that the viscosity at 25°C measured using a Zahn cup #4 was 20 seconds to prepare an ink for printing. Using an anilox roll with a cell volume of 13 cc, the surface of a single-sided treated PET film (manufactured by Toyobo Co., Ltd., trade name "Ester Film 8102") with a thickness of 12 μm, which was corona-treated immediately before applying the ink to refresh the degree of film treatment, was applied with the prepared printing ink, and then dried at 25°C for 48 hours to produce a flexographic printing film.

[0085] <Production of Laminate Film> On the surface of the ink layer side of the gravure printing film or the flexographic printing film, a dry laminating adhesive (trade name: "Seika Bond E372 / C-76", manufactured by Dainichi Seiko Kogyo Co., Ltd.) was applied at a dry coating amount of 3 g / m 2It was applied by gravure printing and dried so as to achieve this. An LLDPE film (product name: "T.U.X HC", manufactured by Mitsui Chemicals Toagosei Co., Ltd., thickness: 60 μm) was overlaid thereon and heat-sealed. Thereafter, aging was performed at 40 °C for 48 hours to obtain a laminated film.

[0086] <Evaluation of Alcohol Dilutability> Regarding the diluted solution obtained by diluting the aqueous ink composition with a diluting medium (methanol / IPA = 8 / 2) at a dilution ratio of 50% by mass (the mass of the diluting medium is 0.5 times the mass of the aqueous ink composition), the viscosity (A) at 25 °C was measured using a Zahn cup #3. Regarding the diluted solution obtained by diluting the aqueous ink composition with a diluting medium (methanol / IPA = 8 / 2) at a dilution ratio of 100% by mass (the mass of the diluting medium is 1 times the mass of the aqueous ink composition), the viscosity (B) at 25 °C was measured using a Zahn cup #3. The viscosity difference represented by viscosity (B) - viscosity (A) was calculated, and the alcohol dilutability was evaluated according to the following evaluation criteria. 〇: 1 second or less (no thickening occurs, and it has excellent alcohol dilutability). △: More than 1 second and 3 seconds or less. ×: More than 3 seconds.

[0087] <Evaluation of Ink Fluidity> The aqueous ink composition after production was placed in a transparent container and stored at 25 °C for 1 day. Then, the transparent container was tilted, and the ink fluidity of the aqueous ink composition was visually confirmed and evaluated according to the following evaluation criteria. 〇: It has good fluidity. △: It has thixotropy and some fluidity is impaired. ×: It has no fluidity.

[0088] <Evaluation of Chroma> The C value of the ink layer of the obtained gravure-printed film or flexo-printed film was measured using a colorimeter (manufactured by X-Rite, Inc., exact). The higher the C value, the better the chroma. * * * *

[0089] <Evaluation of Color Development> The color development property of the ink layer of the obtained gravure printing film or flexographic printing film was visually confirmed and evaluated according to the following evaluation criteria. The better the color development property, the better the pigment dispersibility. For examples where the aqueous ink composition does not contain a pigment, the evaluation of color development property was not performed. ○: It has sufficient density and is clear. △: Either the density or the clarity is impaired. ×: The density is insufficient and it is unclear.

[0090] <Evaluation of Adhesion> After attaching cellophane tape (manufactured by Nichiban Co., Ltd.) to the surface on the ink layer side of the obtained gravure printing film or flexographic printing film, this cellophane tape was quickly peeled off, and the state of the ink layer remaining on the base film (single-sided treated PET film) was visually confirmed. The adhesion of the ink layer to the base film was evaluated according to the following evaluation criteria. 5: The ink layer has not peeled off at all. 4: The ratio of the area of the peeled ink layer to the total area of the ink layer is more than 0% and less than 20%. 3: The ratio of the area of the peeled ink layer to the total area of the ink layer is 20% or more and less than 50%. 2: The ratio of the area of the peeled ink layer to the total area of the ink layer is 50% or more and less than 70%. 1: The ratio of the area of the peeled ink layer to the total area of the ink layer is 70% or more and less than 100%.

[0091] <Evaluation of Laminating Strength> The obtained laminated film was cut to prepare strip-shaped test pieces with a width of 15 mm. Using a universal tensile testing machine (trade name "E3-L", manufactured by Toyo Seiki Seisakusho), the prepared test pieces were subjected to tensile peeling (T-type peeling) under the condition of a tensile speed of 300 mm / min, and the average load at the time of peeling was measured.

[0092] <Evaluation of Boiling Suitability> The obtained laminated film was heat-treated in hot water at 85°C for 30 minutes, and then the presence or absence of a decrease in lamination strength and the presence or absence of laminate peeling (interlayer delamination) were visually confirmed, and the boilability was evaluated according to the following evaluation criteria. 〇: Neither a decrease in lamination strength nor laminate peeling was confirmed. △: A slight decrease in lamination strength or laminate peeling was confirmed. ×: A significant decrease in lamination strength or laminate peeling was confirmed.

[0093]

Table 1

[0094]

Table 2

[0095]

Table 3

[0096]

Table 4

[0097]

Table 5

[0098]

Table 6

[0099]

Table 7

[0100]

Table 8

[0101]

Table 9

[0102] [Application Example] Using a heat seal tester (manufactured by Tester Sangyo Co., Ltd., product name "TP-701-C Heat Seal Tester"), the laminated film of Example 1 was heat-sealed to produce a bag-shaped packaging material having an opening. The test substance (a mixture of acetic acid: water: salad oil = 1:1:1 (mass ratio)) was filled therein, and the opening was heat-sealed with the above heat seal tester to obtain a package. Regarding this package, it was confirmed that it was excellent in boil suitability and laminate strength, and that there were no problems in use.

[0103] [Examples 29 to 31, Comparative Examples 17 to 18] A plurality of aqueous ink compositions shown in Table 10 were mixed in equal amounts to prepare an aqueous ink composition. Regarding the obtained aqueous ink composition, in the same manner as above, a gravure printing film or a flexographic printing film and a laminated film were produced, and alcohol dilutability, ink fluidity, color development property, adhesion, laminate strength, and boil suitability were evaluated. Further, the color matching stability was evaluated by the following method. The evaluation results are shown in Table 10.

[0104] <Evaluation of Color Matching Stability> The difference between the viscosity (C) at 25°C measured using a Zahn cup #4 immediately after mixing a plurality of aqueous ink compositions and the viscosity (D) at 25°C measured using a Zahn cup #4 after storage at 25°C for 1 week was calculated, and the color matching stability was evaluated according to the following evaluation criteria. 〇: Less than ±3 seconds. △: ±3 seconds or more and less than ±5 seconds. ×: ±5 seconds or more.

[0105]

Table 10

Industrial Applicability

[0106] The aqueous ink composition of the present invention is excellent in alcohol dilutability, ink fluidity, pigment dispersibility, and color tone stability, and is useful as an ink for gravure printing or flexographic printing.

Claims

1. An aqueous ink composition containing an aqueous urethane resin and an aqueous medium, wherein the aqueous urethane resin contains an aqueous urethane resin (A1) and an aqueous urethane resin (A2), the aqueous urethane resin (A1) is an ether-based urethane resin having a glass transition temperature of -70 to -30°C, the aqueous urethane resin (A2) is an ester-based urethane resin having a glass transition temperature of 60 to 120°C, and the total content of the aqueous urethane resin (A1) and the aqueous urethane resin (A2) is 20 to 94% by mass based on the total mass of the non-volatile components in the aqueous ink composition. The aqueous ink composition.

2. The aqueous ink composition according to Claim 1, wherein the mass ratio represented by the aqueous urethane resin (A1) / aqueous urethane resin (A2) is 0.08 to 0.

7.

3. The aqueous ink composition according to Claim 1, further containing wax.

4. The aqueous ink composition according to Claim 1, further containing a pigment.

5. The aqueous ink composition according to Claim 4, wherein there is one kind of the pigment in the aqueous ink composition.

6. For an aqueous ink composition obtained by mixing and color-adjusting a plurality of the aqueous ink compositions having different color tones, the difference between the viscosity at 25°C measured by Zahn cup #4 and the viscosity after the color-adjusted aqueous ink composition is allowed to stand at 25°C for one week is less than ±3 seconds. The aqueous ink composition according to Claim 1.

7. The aqueous ink composition according to Claim 1, further containing a curing agent.

8. The aqueous ink composition according to Claim 1, which is for gravure printing or flexographic printing.

9. An aqueous ink set comprising a plurality of aqueous ink compositions having different color tones, wherein each of the plurality of aqueous ink compositions contains an aqueous urethane resin and an aqueous medium, and at least a part of the plurality of aqueous ink compositions further contains a pigment. In each of the plurality of aqueous ink compositions, the aqueous urethane resin contains an aqueous urethane resin (A1) and an aqueous urethane resin (A2), the aqueous urethane resin (A1) is an ether-based urethane resin having a glass transition temperature of -70 to -30 °C, the aqueous urethane resin (A2) is an ester-based urethane resin having a glass transition temperature of 60 to 120 °C, and the total content of the aqueous urethane resin (A1) and the aqueous urethane resin (A2) is 20 to 94% by mass based on the total mass of the non-volatile components in the aqueous ink composition. An aqueous ink set.

10. The aqueous ink set according to claim 9, wherein in each of the plurality of aqueous ink compositions, the mass ratio represented by the aqueous urethane resin (A1) / aqueous urethane resin (A2) is 0.08 to 0.

7.

11. The aqueous ink set according to claim 9, wherein each of the plurality of aqueous ink compositions further contains wax.

12. The aqueous ink set according to claim 9, wherein there is one type of the pigment in the aqueous ink composition containing the pigment.

13. For the aqueous ink composition obtained by mixing and color-adjusting at least two of the plurality of aqueous ink compositions, the difference between the viscosity measured at 25 °C with a Zahn cup #4 and the viscosity after allowing the color-adjusted aqueous ink composition to stand at 25 °C for one week is less than ±3 seconds. The aqueous ink set according to claim 9.

14. The aqueous ink set according to claim 9, further comprising a curing agent.

15. The aqueous ink set according to claim 9, which is for gravure printing or flexographic printing.

16. Comprising a plastic film and an ink layer provided on the plastic film, An ink layer-attached film, wherein the ink layer is an ink layer formed from the aqueous ink composition according to any one of claims 1 to 8.

17. A method for manufacturing an ink layer-attached film, wherein printing is performed on a plastic film using the aqueous ink composition according to any one of claims 1 to 8 to form an ink layer.

18. A method for manufacturing an ink layer-attached film, wherein printing is performed on a plastic film using as it is at least one of the plurality of aqueous ink compositions provided in the aqueous ink set according to any one of claims 9 to 15 to form an ink layer.

19. Prepare an aqueous ink composition obtained by mixing at least two of the plurality of aqueous ink compositions included in the aqueous ink set according to any one of claims 9 to 15 for color adjustment. A method for manufacturing a film with an ink layer, comprising forming an ink layer by printing on a plastic film using the color-adjusted aqueous ink composition.

20. A laminated film comprising the film with an ink layer according to claim 16, an adhesive layer provided on the ink layer of the film with an ink layer, and a resin layer provided on the adhesive layer.

21. A packaging material comprising the laminated film according to claim 20.

Images