Inkjet ink set and laminate film

Abstract

To provide an inkjet ink set which comprises aqueous inkjet ink compositions excellent in laminate strength and heat resistance.SOLUTION: The inkjet ink set comprises: an aqueous yellow ink composition containing at least one selected from the group consisting of PY17, PY83, PY128, PY155 and PY180; an aqueous magenta ink composition containing at least one selected from the group consisting of PR146, PR150, PR176, PR185 and PR254; an aqueous cyan ink composition containing PB15:3; an aqueous black ink composition containing PBk7; and an aqueous violet ink composition containing PV23. Each of the aqueous inkjet ink compositions contains an alkali-soluble or self-emulsifiable polyurethane resin as a binder resin, and an aqueous medium.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an inkjet ink set and a laminate film. [Background technology]

[0002] Generally, food packaging containers made of laminated composite films (laminate films) are used for retort pouch foods, and aqueous inkjet ink compositions for forming the printed ink layer (printed design) are known (e.g., Patent Documents 1-3). However, these aqueous inkjet ink compositions have a problem of poor adhesion (lamination strength) to plastic base films. As an aqueous inkjet ink composition that solves this problem, an aqueous inkjet ink composition for lamination containing a specific alkali-soluble or self-emulsifying polyurethane resin is also known (Patent Document 4). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-250416 A [Patent Document 2] JP 2013-001755 A [Patent Document 3] JP 2013-001775 A [Patent Document 4] JP 2020-029484 A Summary of the Invention [Problem to be solved by the invention]

[0004] On the other hand, retort pouch foods require that the food be packed in the above-mentioned packaging container, the opening be heat-sealed to seal the food, and then heat sterilized (retort treatment) with high-temperature hot water or high-temperature steam exceeding 100°C under pressure. However, some of the aqueous inkjet ink compositions specifically disclosed in Patent Document 4 cause dye transfer to the base film during retort treatment, and it has been found that they are not sufficient in terms of heat resistance.

[0005] Therefore, an object of the present invention is to provide an inkjet ink set having a water-based inkjet ink composition that is excellent in lamination strength and heat resistance. [Means for solving the problem]

[0006] The present invention relates to an inkjet ink set having four color aqueous inkjet ink compositions constituted by an aqueous yellow ink composition, an aqueous magenta ink composition, an aqueous cyan ink composition, and an aqueous black ink composition, or having five color aqueous inkjet ink compositions constituted by the aqueous yellow ink composition, the aqueous magenta ink composition, the aqueous cyan ink composition, the aqueous black ink composition, and an aqueous violet ink composition, wherein the aqueous yellow ink composition contains at least one selected from the group consisting of PY17, PY83, PY128, PY155, and PY180. the aqueous magenta ink composition contains at least one selected from the group consisting of PR146, PR150, PR176, PR185, and PR254, the aqueous cyan ink composition contains PB15:3, the aqueous black ink composition contains PBk7, and the aqueous violet ink composition contains PV23, and each of the aqueous inkjet ink compositions in the four color aqueous inkjet ink compositions and the five color aqueous inkjet ink compositions contains an alkali-soluble or self-emulsifying polyurethane resin as a binder resin, and an aqueous medium.

[0007] The present invention also relates to a laminate film in which a printed layer formed from each of the aqueous ink-jet ink compositions in the ink-jet ink set and a sealant film are provided on a base film. Effect of the Invention

[0008] The inkjet ink set of the present invention is able to exhibit excellent laminate strength and heat resistance by using a combination of aqueous inkjet ink compositions containing specific pigments, and an alkali-soluble or self-emulsifying polyurethane resin as the binder resin for each ink composition. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The inkjet ink set of the present invention has four color aqueous inkjet ink compositions consisting of an aqueous yellow ink composition, an aqueous magenta ink composition, an aqueous cyan ink composition, and an aqueous black ink composition, or has five color aqueous inkjet ink compositions consisting of the aqueous yellow ink composition, the aqueous magenta ink composition, the aqueous cyan ink composition, the aqueous black ink composition, and an aqueous violet ink composition. Each of the four color aqueous inkjet ink compositions and the five color aqueous inkjet ink compositions contains an alkali-soluble or self-emulsifying polyurethane resin as a binder resin, and an aqueous medium.

[0010] <Pigments> The aqueous yellow ink composition contains, as a yellow pigment, at least one selected from the group consisting of PY17, PY128, PY83, PY155, and PY180. Here, "PY" means "CI Pigment Yellow."

[0011] The water-based magenta ink composition contains, as a magenta pigment, at least one pigment selected from the group consisting of PR146, PR150, PR176, PR185, and PR254, where "PR" stands for "CI Pigment Red."

[0012] The aqueous cyan ink composition contains PB15:3 as a cyan pigment, where "PB" stands for "CI Pigment Blue."

[0013] The water-based black ink composition contains PBk7 as a black pigment, where "PBk" stands for "CI Pigment Black."

[0014] The aqueous violet ink composition contains PV23 as a violet pigment, where "PV" stands for "CI Pigment Violet."

[0015] The proportion of each of the above pigments in each of the aqueous inkjet ink compositions is preferably 1% by mass or more, and more preferably 2% by mass or more, from the viewpoint of improving the print density of the printed matter, and is preferably 10% by mass or less, and more preferably 8% by mass or less, from the viewpoint of improving the ejection stability.

[0016] In order to disperse the pigment in an aqueous medium, a pigment dispersant may be used. Examples of the pigment dispersant include low-molecular-weight or high-molecular-weight pigment dispersants described in WO2020 / 039832 and the like.

[0017] <Binder resin> The binder resin is an alkali-soluble or self-emulsifying polyurethane resin, and has one or more anionic groups such as a carboxyl group and a sulfonic acid group. Examples of the alkali-soluble or self-emulsifying polyurethane resin include a reaction product of a diisocyanate compound, a polymer diol compound, and an acid group-containing diol compound, and a reaction product of the diisocyanate compound and an acid group-containing polymer diol compound. At least one type of the alkali-soluble or self-emulsifying polyurethane resin may be used, and two or more types may be used in combination. The alkali-soluble or self-emulsifying polyurethane resin may be used in combination with a pigment dispersant to improve adhesion to the film as described above, or may be used to disperse the pigment (also has a function of improving adhesion to the film). When the alkali-soluble or self-emulsifying polyurethane resin is used as a pigment dispersant to disperse the pigment in an aqueous medium, it is preferable that the alkali-soluble or self-emulsifying polyurethane resin is an alkali-soluble or self-emulsifying polyurethane resin having a hydrazine residue in the molecule.

[0018] The alkali-soluble or self-emulsifying polyurethane resin having a hydrazine residue in the molecule preferably has an acid value of 15 to 50 mgKOH / g, more preferably 15 to 35 mgKOH / g. If the acid value of the alkali-soluble or self-emulsifying polyurethane resin having a hydrazine residue in the molecule is less than 15 mgKOH / g, it becomes difficult to manufacture, and if it is more than 50 mgKOH / g, the water resistance of the printed matter tends to decrease, and the laminate strength tends to decrease. In addition, when the acid value of the alkali-soluble or self-emulsifying polyurethane resin having a hydrazine residue in the molecule is reduced, the alkali-soluble polyurethane resin changes to a self-emulsifying polyurethane resin. From the viewpoint of maintaining a low viscosity of each ink composition of the inkjet ink set of the present invention, a self-emulsifying polyurethane resin is preferred. Here, the self-emulsifying polyurethane resin refers to a polyurethane resin having an ionic group in the molecule and having a property of being stably dispersible by ionizing the ionic group in an aqueous medium. The acid value is a theoretical acid value, and refers to the number of milligrams of potassium hydroxide theoretically required to neutralize 1 g of polyurethane resin, calculated arithmetically based on the molecular weight, blending ratio, and number of anionic groups such as carboxyl groups contained in the molecule of the compound containing an anionic group such as a carboxyl group used as a synthetic component of the polyurethane resin.

[0019] Examples of the diisocyanate compound include aliphatic diisocyanate compounds such as hexamethylene diisocyanate and 2,2,4-trimethylhexamethylene diisocyanate; alicyclic diisocyanate compounds such as isophorone diisocyanate, hydrogenated xylylene diisocyanate and 4,4-cyclohexylmethane diisocyanate; aromatic aliphatic diisocyanate compounds such as xylylene diisocyanate and tetramethylxylylene diisocyanate; and aromatic diisocyanate compounds such as toluylene diisocyanate and diphenylmethane diisocyanate.

[0020] Examples of the polymer diol compound include polyester diol compounds obtained by polycondensation of low-molecular-weight diol components such as linear glycols such as 1,3-propanediol, 1,4-butanediol, and 1,6-hexanediol, branched glycols such as 1,2-propanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, and 2-ethyl-2-butyl-1,3-propanediol, and ether-based diols such as diethylene glycol and triethylene glycol, and dibasic acid components such as adipic acid and phthalic acid, or by ring-opening reaction of cyclic ester compounds such as lactones, and acid Examples of the polyether diol compounds include polyether diol compounds obtained by homopolymerizing or copolymerizing ethylene oxide, propylene oxide, tetrahydrofuran, etc., polyalkylene glycols such as polyethylene glycol and polypropylene glycol, polyether diol compounds such as alkylene oxide adducts of bisphenol A with ethylene oxide, propylene oxide, etc., and further polycarbonate diol compounds obtained by reacting carbonate components such as alkylene carbonate, diallyl carbonate, dialkyl carbonate, etc. or phosgene with the low molecular weight diol components, polybutadiene glycols, etc. Among these, polypropylene glycol and polyester diol compounds are preferable as the alkali-soluble or self-emulsifying polyurethane resin having a hydrazine residue in the molecule from the viewpoint of boiling and retorting suitability.

[0021] Examples of the acid group-containing diol compound include those represented by the general formula (1): [ka] (In general formula (1), R 1 represents a hydrogen atom, or a linear or branched alkyl group having 1 to 8 carbon atoms.), aliphatic carboxylic acid-containing polyols obtained by reacting succinic acid, adipic acid, or the like with a lower polyol, and aromatic carboxylic acid-containing polyols obtained by reacting phthalic acid, trimellitic acid, pyromellitic acid or anhydride thereof with a lower polyol.

[0022] Examples of the acid group-containing polymer diol compound include polymer diol compounds obtained by reacting the polymer diol compound with a tetrabasic acid anhydride such as pyromellitic anhydride, or by ring-opening polymerization of lactones using dimethylolpropionic acid or the like as an initiator.

[0023] The method of introducing a hydrazine residue into the alkali-soluble or self-emulsifying polyurethane resin having a hydrazine residue in the molecule can be by using a chain extender or a reaction terminator. For example, the reaction terminator used to introduce a hydrazine residue into the polyurethane molecule is a compound having a functional group for reacting with an isocyanate group and a hydrazine residue, and polyaminohydrazide, hydrazine (hydrazine hydrate), and alkylene dihydrazine or a saturated aliphatic dibasic acid or a dihydrazide compound of an unsaturated dibasic acid represented by the following general formula (2): H2N-NH-X-NH-NH2 (2) (wherein X represents an alkylene group having 1 to 8 carbon atoms, or a residue of a saturated or unsaturated dibasic acid having 1 to 10 carbon atoms) can also be used. Specific examples of the alkylene dihydrazine include methylene dihydrazine, ethylene dihydrazine, and butylene dihydrazine. Specific examples of the dihydrazide compounds of saturated aliphatic dibasic acids include oxalic acid dihydrazide, malonic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, and sebacic acid dihydrazide. Specific examples of the dihydrazide compounds of unsaturated dibasic acids include phthalic acid dihydrazide, fumaric acid dihydrazide, and itaconic acid dihydrazide.

[0024] If necessary, a reaction terminator may be used, for example, an alkylamine such as n-propylamine, n-butylamine, or N,N-di-n-butylamine; or an alkanolamine such as monoethanolamine or diethanolamine.

[0025] The method for synthesizing the alkali-soluble or self-emulsifying polyurethane resin (alkali-soluble or self-emulsifying polyurethane resin having a hydrazine residue in the molecule) may be a known polyurethane resin synthesis method, and may involve reacting the above components all at once or in portions.

[0026] The weight average molecular weight of the alkali-soluble or self-emulsifying polyurethane resin having a hydrazine residue in the molecule is preferably 2,000 to 100,000, more preferably 3,000 to 50,000, and even more preferably 5,000 to 30,000. If the weight average molecular weight is less than 2,000, the ink film may become fragile, while if the weight average molecular weight exceeds 100,000, the viscosity of the aqueous inkjet ink composition may increase even at a small content, which may cause problems in forming the ink film. The weight average molecular weight of the present invention can be measured by gel permeation chromatography (GPC). As an example, chromatography can be performed using a Water2690 (manufactured by Waters) as a GPC device and a PLgel, 5 μm, MIXED-D (manufactured by Polymer Laboratories) as a column under conditions of tetrahydrofuran as a developing solvent, a column temperature of 25° C., a flow rate of 1 milliliter / minute, an RI detector, a sample injection concentration of 10 milligrams / milliliter, and an injection volume of 100 microliters, and the weight average molecular weight can be calculated in terms of polystyrene.

[0027] The alkali-soluble or self-emulsifiable polyurethane resin having a hydrazine residue in the molecule is preferably used as an aqueous resin varnish by dissolving or emulsifying it in water in the presence of a basic compound.

[0028] Examples of a method for dissolving or emulsifying the alkali-soluble or self-emulsifying polyurethane resin having a hydrazine residue in its molecule in an aqueous medium described below include a method in which a basic compound in an amount that approximately neutralizes the alkali-soluble or self-emulsifying polyurethane resin having a hydrazine residue in its molecule is dissolved in an aqueous medium described below, and then the alkali-soluble or self-emulsifying polyurethane resin having a hydrazine residue in its molecule is added and stirred with a high-speed stirrer.

[0029] The basic compound is not particularly limited, and a commonly used basic compound can be used, for example, alkylamines such as butylamine and triethylamine, alkanolamines such as monoethanolamine, diethanolamine and triethanolamine, morpholine, aqueous ammonia, sodium hydroxide, etc. The amount of the basic compound is appropriately set depending on the physical properties and the amount used of the alkali-soluble or self-emulsifying polyurethane resin having a hydrazine residue in the molecule used, and may be used alone or in combination of two or more kinds.

[0030] The content of the alkali-soluble or self-emulsifying polyurethane resin having a hydrazine residue in the molecule is appropriately adjusted depending on the viscosity behavior in the aqueous medium to be used, the components to be used in combination, the desired ink properties, etc., but from the viewpoint of imparting storage stability, ejection stability, and laminate strength (peel strength between the base film and the sealant film) in each of the aqueous inkjet ink compositions, the content is preferably 0.3 to 4.0 mass% in terms of solid content, and more preferably 0.7 to 3.5 mass%. If the blending amount is less than 0.3 mass%, the storage stability and laminate strength tend to decrease, and if it is more than 4.0 mass%, the blocking property tends to decrease.

[0031] <Aqueous medium> The aqueous medium preferably contains water and, if necessary, a water-miscible organic solvent.

[0032] The water-miscible organic solvent is blended depending on the desired performance such as solubility of the alkali-soluble or self-emulsifying polyurethane resin having a hydrazine residue in the molecule, drying property, moisture retention, leveling property during printing, etc. The water-miscible organic solvent is not particularly limited as long as it does not inhibit the effects of the present invention and does not damage the inkjet printer, and monoalcohols, mono- and polyalkylene glycols and their alkyl ether compounds, and mono- and polyglycerin and their ethylene oxide adducts are suitable.

[0033] Specific examples of the monoalcohols include methanol, ethanol, n-propanol, n-butanol, n-pentanol, n-hexanol, n-heptanol, n-octanol, n-nonyl alcohol, n-decanol, or isomers thereof, cyclopentanol, cyclohexanol, etc., and preferable are alcohols in which the alkyl group has 1 to 6 carbon atoms.

[0034] Specific examples of the mono- and polyalkylene glycols include ethylene glycol, propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 1,2-pentanediol, 1,5-pentanediol, neopentyl glycol, 1,2-hexanediol, 1,6-hexanediol, 1,2-cyclohexanediol, heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, glycerin, pentaerythritol, diethylene glycol, dipropylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, polypropylene glycol, and thiodiglycol.

[0035] Specific examples of the alkyl ether compounds of the mono- and polyalkylene glycols include ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, ethylene glycol monoethyl ether, ethylene glycol diethyl ether, ethylene glycol monopropyl ether, ethylene glycol isopropyl ether, ethylene glycol monobutyl ether, ethylene glycol isobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, and dipropylene glycol mono-n-butyl ether.

[0036] In the aqueous medium, the mixing ratio of water to the water-miscible organic solvent may be set according to the properties of the ink composition of the intended inkjet ink set, but it is usually preferable that the aqueous medium contains 2 to 30% by weight of the water-miscible organic solvent.

[0037] Furthermore, each of the aqueous inkjet ink compositions may contain any component depending on the purpose. For example, additives such as known resins, resin emulsions, wax emulsions, pigment dispersants, surfactants, antifungal agents, rust inhibitors, thickeners, antioxidants, ultraviolet absorbers, storage improvers, antifoaming agents, and pH adjusters may also be added.

[0038] <Method of preparing aqueous inkjet ink composition> The preparation of each of the aqueous ink-jet ink compositions may be carried out by utilizing a conventional preparation method, and the above-mentioned components may be added and mixed in order or simultaneously. For example, there may be mentioned a method in which (1) the aqueous resin varnish, pigment, and, if necessary, a pigment dispersant are mixed, and then a pigment dispersion (ink base) is prepared using various dispersing machines, such as a ball mill, attritor, roll mill, sand mill, agitator mill, etc., and the remaining materials are added to prepare an aqueous ink-jet ink composition; or (2) the pigment is dispersed by the above-mentioned method, and then an alkali-soluble resin is precipitated on the pigment surface by an acid precipitation method or the ion exchange means described in the republished patent publication WO2005 / 116147 to obtain a resin-coated pigment, which is then neutralized with a basic compound and redispersed in water using various dispersing machines (such as a high-speed stirring device), and the remaining materials are added to prepare an aqueous ink-jet ink composition.

[0039] The initial viscosity of each of the aqueous inkjet ink compositions is preferably from 2.0 to 20.0 mPa·s, and more preferably from 3.0 to 10.0 mPa·s.

[0040] <Lamination film> The laminate film of the present invention includes a base film, a printed layer formed from each of the aqueous ink-jet ink compositions, and a sealant film. The printed layer and the sealant film are usually laminated via a laminating adhesive. The printed layer may also include a printed layer made of a conventional white ink composition. From the viewpoint of heat resistance, the white ink composition preferably contains PW6 as a white pigment, and when the aqueous ink-jet ink composition is an ink-jet ink composition, from the viewpoint of lamination strength, it is preferable that the white ink composition contains each of the components in the aqueous ink-jet ink composition. The ratio of the white pigment in the white ink composition is preferably 4% by mass or more, more preferably 8% by mass or more, and is preferably 30% by mass or less, and more preferably 20% by mass or less. However, printing with the white ink composition is not limited to ink-jet printing, and other printing methods such as flexographic printing and gravure printing can be applied.

[0041] The base film is formed from a thermoplastic resin having a transparent film-forming ability, and examples of the main materials used in the field of food packaging containers include polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polyethylene terephthalate, polybutylene terephthalate, nylon-6, nylon-6,6, polyvinyl chloride, polyvinylidene chloride, etc.

[0042] The base film is preferably subjected to uniaxial or biaxial stretching treatment, and may be subjected to plasma treatment, corona discharge treatment, or the like.

[0043] The laminating adhesive can be appropriately selected from those conventionally used in laminating, and examples of such adhesives include urethane resin-based, imino group-containing resin-based, butadiene resin-based, etc. Among them, urethane resin-based adhesives are preferred, and a two-liquid adhesive consisting of a combination of an isocyanate group-terminated urethane prepolymer consisting of a polyol component and an excess of an aliphatic polyisocyanate component, and a polyol component, or a two-liquid adhesive consisting of a combination of a hydroxyl group-terminated urethane prepolymer consisting of an excess of a polyol component and an aliphatic polyisocyanate component, and a polyisocyanate component, can be used, and an epoxy compound or a silane coupling agent can be included as necessary.

[0044] The application of the laminating adhesive and the lamination of the sealant film can be carried out using a known dry lamination processing apparatus equipped with various types of coating devices such as a roll coater, a bar coater, a gravure coater, and the like.

[0045] Examples of the material for the sealant film include unoriented polyethylene, linear low-density polyethylene, unoriented polypropylene, and ethylene-vinyl acetate copolymer.

[0046] Furthermore, one or more functional layers may be provided between the printed layer and the sealant film for the purpose of improving gas barrier properties, strength reinforcement, etc. Examples of such functional layers include a silica-deposited film layer or an alumina-deposited film layer for the purpose of improving gas barrier properties, and a stretched nylon film layer for the purpose of improving strength reinforcement. In addition, a primer layer may be provided between the base film and the printed layer from the viewpoint of improving printability and adhesion.

[0047] The laminate film preferably has a lamination strength (peel strength between the base film and the sealant film) of 50 g / 15 mm or more, and more preferably 100 g / 15 mm or more.

[0048] The laminate strength was measured by measuring the peel strength (dry laminate strength) when the laminate film was left at 40°C for 3 days, cut into a 15 mm width to prepare a sample piece, and T-type peeling was performed using a peel tester (manufactured by Yasuda Seiki Seisakusho Co., Ltd.).

[0049] To make a bag from the laminate film, the film can be folded in half so that the sealant film faces the inside of the container, or the composite film can be overlapped and the ends can be heat-melted and pressed using a heat sealer or the like. This method can be applied to packaging containers with various types of heat seals, such as three-sided seal, four-sided seal, envelope seal, gable seal, and gusset seal. EXAMPLES

[0050] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In the examples and comparative examples, "parts" and "%" are by mass unless otherwise specified.

[0051] <Production of Water-Based Resin Varnish 1> In a four-neck flask equipped with a thermometer, a stirrer, a cooling tube, and a nitrogen inlet tube, 200 parts of polypropylene glycol with a number average molecular weight of 2,000 and 57.4 parts of isophorone diisocyanate were charged, and while introducing nitrogen gas, the mixture was reacted at 100 to 105 ° C. for 4 hours under stirring, and then 13.4 parts of dimethylolpropionic acid were charged and reacted at 100 to 110 ° C. for 2 hours. After confirming that the dimethylolpropionic acid had completely reacted, the mixture was cooled to 100 ° C., and 492.4 parts of water, 8.3 parts of sodium hydroxide with a solid content of 25%, and 3.4 parts of ammonia 25% aqueous solution were charged to make the mixture aqueous, and the reaction was stopped with 3.2 parts of aminoethanolamine and 2.5 parts of hydrazine hydrate, and an alkali-soluble or self-emulsifying polyurethane resin solution 1 with a solid content of 30%, a weight average molecular weight of 20,000, and a resin acid value of 24 having a hydrazine residue in the molecule was obtained.

[0052] <Production of Water-Based Resin Varnish 2> In a four-neck flask equipped with a thermometer, a stirrer, a cooling tube, and a nitrogen inlet tube, 300 parts of polyneopentyl adipate diol having a number average molecular weight of 1,000 and 133.2 parts of isophorone diisocyanate were charged, and while introducing nitrogen gas, the mixture was reacted at 100 to 105 ° C. for 4 hours under stirring, and then 24.1 parts of dimethylolpropionic acid were charged and reacted at 100 to 110 ° C. for 2 hours. After confirming that the dimethylolpropionic acid had completely reacted, the mixture was cooled to 100 ° C., and 1128 parts of water and 20.2 parts of triethylamine were charged to make it aqueous, and the reaction was stopped with 34.8 parts of dihydrazine adipate, to obtain an alkali-soluble or self-emulsifying polyurethane resin solution 2 having a solid content of 30%, a weight average molecular weight of 22,000, and a resin acid value of 24 and a hydrazide residue in the molecule.

[0053] <Water-based acrylic resin varnish> As the water-based acrylic resin varnish, Vinyblan 2687 (manufactured by Nissin Chemical Industry Co., Ltd., acrylic resin emulsion, solid content 30% by mass) was used.

[0054] <Preparation of color ink base> 23.7 parts by mass of the above water-based resin varnish was mixed with 64.3 parts by mass of water to prepare a resin varnish for dispersing pigments. 12 parts by mass of the following pigments were further added to this varnish, stirred and mixed, and then milled in a wet circulation mill to prepare various color ink bases. <Pigments> [Example Pigments] PY17 (Graphtol Yellow GG, Clariant) PY83 (LIONOL YELLOW TT-1842, manufactured by Toyo Color Co., Ltd.) PY128 (Cromophtal Yellow L 0990, manufactured by BASF) PY155 (Cromophtal Yellow 2GF, manufactured by BASF) PY180 (Cromophthalic Yellow K 1410, manufactured by BASF) PR146 (SYMULER Fast Red 4580, manufactured by DIC) PR150 (Carmine MC-707, manufactured by Arimoto Chemical Industry Co., Ltd.) PR176 (SUNBRITE RED 176, manufactured by DIC) PR185 (SYMULAR Fast Red 4594, manufactured by DIC) PR254 (Irgazin Red L 3670 HD, manufactured by BASF) PB15:3 (HELIOGEN BLUE D 7088, manufactured by BASF) PV23 (Cromophtal Violet D 5800, manufactured by BASF) PBk7 (PRINTEX90, manufactured by Degussa) [Comparative example pigment] PY74 (Seika First Yellow 2054K, manufactured by Dainichi Seika Chemicals) PR170 (Seika Fast Red 3820, manufactured by Dainichi Seika Chemicals Co., Ltd.) PV19 (Cromophthal Violet D 5800, manufactured by BASF)

[0055] <Preparation of White Ink Base> 40.0 parts by mass of the above-mentioned aqueous resin varnish was mixed with 20.0 parts by mass of water to prepare a resin varnish for dispersing pigments. 40 parts by mass of PW6 (trade name R-960, manufactured by DuPont) was further added to this varnish, stirred and mixed, and then milled in a wet circulation mill to prepare a white ink base.

[0056] <Example 1> <Production of aqueous inkjet ink composition> The above color ink base, propylene glycol, surfactants Olfine E1004 (active ingredient 100%, manufactured by Nissin Chemical Industry Co., Ltd.) and Olfine E1010 (active ingredient 100%, manufactured by Nissin Chemical Industry Co., Ltd.), wax emulsion AQUACER 515 (active ingredient 35%, manufactured by BYK), and water were stirred and mixed to obtain the mass ratios shown in Table 1, thereby producing the aqueous inkjet ink composition of Example 1.

[0057] <Examples 2 to 19 and Comparative Examples 1 to 4> <Production of aqueous inkjet ink composition> In each of the Examples and Comparative Examples, the aqueous inkjet ink compositions were produced in the same manner as in Example 1, except that the raw materials and the amounts thereof used were changed as shown in Tables 1 and 2.

[0058] <Evaluation of aqueous inkjet ink compositions> The evaluation was carried out by the following methods, and the results are shown in Tables 1 and 2.

[0059] <Evaluation of storage stability> Each of the aqueous inkjet ink compositions obtained above was placed in a glass bottle, and the viscosity at 25°C was measured using a viscometer (RE100L model, manufactured by Toki Sangyo Co., Ltd.). The bottle was then sealed and stored at 60°C for one month, and the viscosity after storage (25°C) was measured using the viscometer. The stability over time was evaluated as the rate of viscosity change (viscosity after one month at 60°C - viscosity before storage / viscosity before storage). [Evaluation Criteria] ○: Viscosity change rate is less than 5% △: Viscosity change rate is 5% or more but less than 10% ×: Viscosity change rate is 10% or more and less than 30%

[0060] <Evaluation of ejection stability> Each of the aqueous inkjet ink compositions obtained above was filled into the cartridge of an inkjet printer PX105 (manufactured by Epson Corporation), and printing was carried out on photo paper GL-101A450 (manufactured by Canon Inc.) to evaluate the ejection stability. [Evaluation Criteria] ○: No print disturbance and stable discharge △: There is some printing distortion, but the ink can still be discharged. ×: Printing is distorted and cannot be discharged stably.

[0061] <Evaluation of heat resistance> Each of the aqueous inkjet ink compositions obtained above was printed on an ONY film (N1102, manufactured by Toyobo Co., Ltd.) using a 0.15 mm bar coater to form a printed layer, thereby producing a printed product. 2 A urethane adhesive (Takelac A-616 / Takenate A-65, manufactured by Mitsui Chemical Polyurethanes) was applied in an amount of 100 μm, and a non-oriented polypropylene film (RXC-22, thickness 60 μm, manufactured by Mitsui Chemicals Tohcello) was laminated using a dry laminator, and then stored at 40 ° C for 3 days to obtain a laminate film (1). In addition, a laminate film (2) without a printed layer was obtained by the same method as above, except that a printed layer was not formed. The laminate film (1) and the laminate film (2) were overlapped so that the ONY film surfaces were aligned, and then sandwiched and fixed between metal plates, and immersed in pressurized hot water at 120 ° C for 30 minutes, and the transfer of dye to the laminate film (2) was evaluated visually. [Evaluation Criteria] ○: No dye transfer observed ×: Clearly visible dye transfer

[0062] <Evaluation of Laminate Strength> A biaxially oriented polyethylene terephthalate (PET) film (Toyobo Co., Ltd., E-5102, thickness 12 μm) corona-discharge-treated on one side and a biaxially oriented polypropylene (OPP) film (Toyobo Co., Ltd., Pylen P-2161, thickness 25 μm) corona-discharge-treated on one side were printed with each of the aqueous inkjet ink compositions obtained above using a 0.15 mm bar coater, and then an isocyanate-based adhesive (Takenate A-358 / Takelac A-50 ethyl acetate solution, Takeda Pharmaceutical Co., Ltd.) was applied, and a non-oriented polypropylene film was laminated with a dry laminator to obtain a laminate film. After aging for 3 days at 40°C, these laminate films were cut into 15 mm wide specimens, and the peel strength (lamination strength) was measured when T-type peeling was performed with a peel tester (Yasuda Seiki Seisakusho Co., Ltd.). [Evaluation Criteria] ○: Peel strength is 100g / 15mm or more △: Peel strength is 50g / 15mm or more and less than 100g / 15mm ×: Peel strength is less than 50g / 15mm

[0063] <Evaluation of overprint lamination strength with water-based white inkjet ink composition> A biaxially oriented polyethylene terephthalate (PET) film (Toyobo Co., Ltd., E-5102, thickness 12 μm) corona-discharge-treated on one side and a biaxially oriented polypropylene (OPP) film (Toyobo Co., Ltd., Pylen P-2161, thickness 25 μm) corona-discharge-treated on one side were printed with each of the aqueous inkjet ink compositions obtained above, other than the white ink composition, using a 0.15 mm bar coater, and then an aqueous white inkjet ink composition was printed using a 0.15 mm bar coater. An isocyanate-based adhesive (Takenate A-358 / Takelac A-50 ethyl acetate solution, Takeda Pharmaceutical Co., Ltd.) was applied, and a non-oriented polypropylene film was laminated using a dry laminator to obtain a laminate film. After aging at 40° C. for 3 days, these laminate films were cut into 15 mm widths to prepare test pieces, and the peel strength (lamination strength) was measured when T-type peeling was performed using a peel tester (manufactured by Yasuda Seiki Seisakusho Co., Ltd.). [Evaluation Criteria] ○: Peel strength is 100g / 15mm or more △: Peel strength is 50g / 15mm or more and less than 100g / 15mm ×: Peel strength is less than 50g / 15mm

[0064] <Evaluation of overprint lamination strength with water-based white flexographic ink composition> A case where a water-based white flexographic ink composition for lamination is used instead of the water-based white inkjet ink composition will be described.

[0065] <Production of Water-Based Urethane Resin Emulsion> In a four-neck flask equipped with a thermometer, a stirrer, a cooling tube, and a nitrogen inlet tube, 300 parts of polyneopentyl adipate diol having a number average molecular weight of 1,000 and 133.2 parts of isophorone diisocyanate were charged, and while introducing nitrogen gas, the mixture was reacted at 100 to 105 ° C. for 4 hours under stirring, and then 24.1 parts of dimethylolpropionic acid were charged and reacted at 100 to 110 ° C. for 2 hours. After confirming that the dimethylolpropionic acid had completely reacted, the mixture was cooled to 100 ° C., and 1128 parts of water and 20.2 parts of triethylamine were charged to make it aqueous, and the reaction was stopped with 34.8 parts of dihydrazine adipate, to obtain an aqueous polyurethane resin solution with a solid content of 30% and a resin acid value of 24.

[0066] <Production of Water-Based White Flexographic Ink Composition for Lamination> 40 parts of PW6 (trade name R-960, manufactured by DuPont), 2 parts (solids) of a water-soluble acrylic resin (styrene-lauryl methacrylate-acrylic acid copolymer (acid value 100 mgKOH / g, weight average molecular weight 11000, neutralized with ammonia, solids content 28% by mass)), and 10 parts (solids) of an aqueous polyurethane resin solution were kneaded using a paint conditioner manufactured by Red Devil Co., Ltd., and further 0.5 parts of an acetylene-based surfactant (acetylene-based surfactant: 2,4,7,9-tetramethyl-5-decyne-4,7-diol, HLB value 4), 5.0 parts of propylene glycol as a water-soluble organic solvent, 2 parts of a curing agent (SU-125F (aziridine-based curing agent, solids content 25%, manufactured by Meisei Chemical Industry Co., Ltd.)), and 42.5 parts of water were added and stirred to obtain an aqueous white flexographic ink composition for lamination.

[0067] <Creating printed matter> On the treated surface of the film, each of the aqueous inkjet ink compositions obtained above other than the white ink was printed on an ONY film (N1102, manufactured by Toyobo Co., Ltd.) using a 0.15 mm bar coater to form a printed layer, and a printed matter was produced. Next, a flexographic printing machine was used to overprint and print the aqueous flexographic printing white ink composition for lamination under the following conditions, and the resulting print was dried to obtain a printed matter. An isocyanate-based adhesive (Takenate A-358 / Takelac A-50 ethyl acetate solution manufactured by Takeda Pharmaceutical Co., Ltd.) was then applied, and a non-oriented polypropylene film was laminated using a dry laminator to obtain a laminate film. After aging for 3 days at 40°C, these laminate films were cut into 15 mm wide pieces to prepare sample pieces, and the peel strength (lamination strength) was measured when T-type peeling was performed using a peel tester (manufactured by Yasuda Seiki Seisakusho Co., Ltd.). (Printing method / printing conditions) Printing room environment: Temperature 25°C, humidity 50% Coating machine: Flexographic printing machine Coating speed: 150m / min Printing plate: Prints white color Printing plate: Solid plate Drying temperature: 55℃ [Evaluation Criteria] ○: Peel strength is 100g / 15mm or more △: Peel strength is 50g / 15mm or more and less than 100g / 15mm ×: Peel strength is less than 50g / 15mm

[0068] [Table 1]

[0069] [Table 2]

Claims

1. four color aqueous ink-jet ink compositions each including an aqueous yellow ink composition, an aqueous magenta ink composition, an aqueous cyan ink composition, and an aqueous black ink composition; or an inkjet ink set having five color aqueous inkjet ink compositions including the aqueous yellow ink composition, the aqueous magenta ink composition, the aqueous cyan ink composition, the aqueous black ink composition, and an aqueous violet ink composition, the water-based yellow ink composition contains at least one selected from the group consisting of PY17, PY83, PY128, PY155, and PY180, The water-based magenta ink composition contains at least one selected from the group consisting of PR146, PR150, PR176, PR185, and PR254, The aqueous cyan ink composition contains PB15:3, The water-based black ink composition contains PBk7, The aqueous violet ink composition contains PV23, The inkjet ink set is characterized in that each of the four color aqueous inkjet ink compositions and the five color aqueous inkjet ink compositions contains an alkali-soluble or self-emulsifying polyurethane resin as a binder resin, and an aqueous medium.

2. 2. The ink-jet ink set according to claim 1, wherein the alkali-soluble or self-emulsifiable polyurethane resin is a reaction product of a diisocyanate, a polymeric diol compound, and an acid group-containing diol compound.

3. 3. The ink-jet ink set according to claim 1, wherein the alkali-soluble or self-emulsifying polyurethane resin is an alkali-soluble or self-emulsifying polyurethane resin having a hydrazine residue in the molecule.

4. The ink-jet ink set according to claim 2, wherein the polymer diol compound is a polypropylene glycol and / or a polyester diol compound.

5. The inkjet ink set according to claim 3, wherein a ratio of the alkali-soluble or self-emulsifiable polyurethane resin having a hydrazine residue in the molecule is 0.3 to 4.0% by mass in each of the aqueous inkjet ink compositions.

6. 6. The ink-jet ink set according to claim 3, wherein the alkali-soluble or self-emulsifiable polyurethane resin having a hydrazine residue in the molecule has an acid value of 15 to 35 mgKOH / g.

7. 7. The ink-jet ink set according to claim 1, wherein each of the water-based ink-jet ink compositions is for lamination.

8. 8. A laminate film comprising a base film and a print layer formed from each of the aqueous ink-jet ink compositions in the ink-jet ink set according to claim 1, and a sealant film.

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