Pretreatment liquid for inkjet ink, ink set, image recording method, method for producing laminate, image recorded matter, and laminate

Abstract

The invention relates to a pretreatment liquid for ink-jet ink and application thereof. The pretreatment liquid for ink-jet ink contains water, a coagulant, nonionic urethane resin and a cross-linking agent.

Description

Technical Field

[0001] The present invention relates to a pre-treatment liquid for inkjet ink, an ink set, an image recording method, a method for producing a laminate, an image recorded article, and a laminate. Background Art

[0002] In recent years, various studies have been conducted on pretreatment liquids for inkjet recording on non-absorbing substrates.

[0003] For example, Patent Document 1 discloses a pre-treatment liquid for inkjet recording that is excellent in image fixability, storage stability, and lamination strength to non-absorbent substrates and is capable of high-definition image quality printing. The pre-treatment liquid contains water-insoluble resin particles, a coagulant, a cross-linking agent, and water, wherein the water-insoluble resin particles contain composite resin particles in which a polyolefin-based resin is contained in a polyurethane-based resin.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2019-177510 Summary of the Invention

[0005] Technical issues to be solved by the invention

[0006] In some cases, an image recorded material is obtained by sequentially applying an inkjet ink pretreatment liquid and an inkjet ink to an impermeable substrate, and then laminating a laminating substrate onto the image recorded material to produce a laminate. In some cases, the laminate is required to have boiling resistance (i.e., resistance to boiling treatment).

[0007] An embodiment of the present invention aims to provide an inkjet ink pretreatment liquid that can improve the boiling resistance of a laminated body when the inkjet ink pretreatment liquid and inkjet ink are sequentially applied to a non-permeable substrate to record an image to obtain an image recorded object, and a laminating substrate is laminated on the image in the obtained image recorded object to produce a laminated body.

[0008] Another embodiment of the present invention aims to provide an ink set including the inkjet ink pre-treatment liquid, an image recording method using the pre-treatment liquid, a method for producing a laminate, an image recorded article, and a laminate.

[0009] Means for solving technical problems

[0010] The present invention includes the following aspects.

[0011] <1> A pretreatment liquid for inkjet ink contains water, a coagulant, a nonionic urethane resin and a crosslinking agent.

[0012] <2> according to <1> The inkjet ink pretreatment liquid, wherein:

[0013] The cross-linking agent contains a compound having at least one of a carbodiimide group and an oxazoline group.

[0014] <3> according to <1> or <2> The inkjet ink pretreatment liquid, wherein:

[0015] The content of the cross-linking agent is 2.0% by mass to 50% by mass based on the total amount of the nonionic urethane resin.

[0016] <4> according to <1> to <3> The pre-treatment liquid for inkjet ink according to any one of the preceding claims, wherein

[0017] The content of the cross-linking agent is 0.10% by mass to 5.00% by mass relative to the total amount of the inkjet ink pre-treatment liquid.

[0018] <5> An ink set comprising:

[0019] <1> to <4> The pretreatment liquid for inkjet ink according to any one of the preceding claims; and

[0020] Inkjet ink contains water, pigment and resin with carboxyl group.

[0021] <6> according to <5> The ink set, wherein

[0022] The resin having a carboxyl group contained in the inkjet ink includes a urethane resin having a carboxyl group.

[0023] <7> according to <5> or <6> The ink set, wherein

[0024] The inkjet ink is a white ink containing a white pigment.

[0025] <8> An image recording method comprises the following steps:

[0026] Will <1> to <4> applying the inkjet ink pretreatment solution described in any one of the preceding claims to a non-permeable substrate; and

[0027] An inkjet ink containing water, a pigment, and a resin having a carboxyl group is applied by an inkjet method to the area of ​​the non-permeable substrate to which the inkjet ink pre-treatment liquid has been applied.

[0028] <9> according to <8> The image recording method, wherein:

[0029] The resin having a carboxyl group contained in the inkjet ink includes a urethane resin having a carboxyl group.

[0030] <10> according to <8> or <9> The image recording method, wherein:

[0031] The inkjet ink is a white ink containing a white pigment.

[0032] <11> according to <8> to <10> The image recording method according to any one of the preceding claims, wherein:

[0033] The amount of the crosslinking agent in the inkjet ink pre-treatment liquid applied to the non-permeable substrate is 1.0% to 30% by mass relative to the amount of the carboxyl group-containing resin in the inkjet ink applied to the non-permeable substrate.

[0034] <12> A method for manufacturing a laminate, comprising the following steps:

[0035] pass <8> to <11> The image recording method according to any one of the preceding claims obtains an image recorded article comprising the impermeable substrate and an image disposed on the impermeable substrate; and

[0036] A laminating substrate is laminated on the side of the image recorded material on which the image is arranged to obtain a laminate.

[0037] <13> An image recorded material comprises an impermeable substrate and an image disposed on the impermeable substrate.

[0038] The image contains:

[0039] a pretreatment layer disposed on the non-permeable substrate and containing a coagulant, a nonionic urethane resin, and a cross-linking agent; and

[0040] The ink layer is disposed on the pretreatment layer and contains a pigment and a resin having a carboxyl group.

[0041] <14> A laminate comprising:

[0042] <13> the image record; and

[0043] A laminating substrate is laminated on the image of the image recorded material.

[0044] Effects of the Invention

[0045] According to one embodiment of the present invention, a pre-treatment liquid for inkjet ink is provided, which can improve the boiling resistance of a laminated body when the pre-treatment liquid for inkjet ink and the inkjet ink are sequentially applied to a non-permeable substrate to record an image to obtain an image recorded object, and a laminating substrate is laminated on the image in the obtained image recorded object to produce a laminated body.

[0046] According to another embodiment of the present invention, there are provided an ink set including the inkjet ink pre-treatment liquid, an image recording method using the pre-treatment liquid, a method for producing a laminate, an image recorded article, and a laminate. DETAILED DESCRIPTION

[0047] Hereinafter, the inkjet ink set for non-permeable substrates, the image recording method, the method for producing a laminate, the image recorded article, and the laminate of the present invention will be described in detail.

[0048] In this specification, the numerical range expressed using "to" means a range including the numerical values ​​described before and after "to" as the minimum value and the maximum value, respectively.

[0049] In the numerical ranges described in this specification, the upper limit or lower limit of a numerical range may be replaced by the upper limit or lower limit of another numerical range described in this specification. In addition, in the numerical ranges described in this specification, the upper limit or lower limit of a numerical range may be replaced by the value shown in the Examples.

[0050] In this specification, when a plurality of substances corresponding to each component are present in a composition, the amount of each component in the composition represents the total amount of the plurality of substances present in the composition, unless otherwise specified.

[0051] In this specification, a combination of two or more preferred aspects is a more preferred aspect.

[0052] In this specification, the term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes as long as the intended purpose of the process can be achieved.

[0053] In this specification, “image” refers to the entire film formed by sequentially applying the pre-treatment liquid and the ink, and “image recording” refers to the formation of an image (ie, a film).

[0054] Furthermore, the concept of "image" in this specification also includes a solid image.

[0055] In this specification, "(meth)acrylate" is a concept including both acrylate and methacrylate. Furthermore, "(meth)acrylic acid" is a concept including both acrylic acid and methacrylic acid.

[0056] In this specification, "boiling treatment" refers to a treatment in which an object (specifically, a laminate) is immersed in water at 60 to 100°C and heated for a predetermined time (for example, 10 to 120 minutes).

[0057] [Pretreatment liquid for inkjet ink]

[0058] The pre-treatment liquid for inkjet ink of the present invention (hereinafter also simply referred to as "pre-treatment liquid") contains water, a coagulant, a nonionic urethane resin, and a cross-linking agent.

[0059] The pretreatment liquid of the present invention can improve the boiling resistance of a laminated body when an image recorded material is obtained by sequentially applying the pretreatment liquid and inkjet ink (hereinafter also referred to as "ink") to an impermeable substrate to record an image, and then laminating a laminating substrate onto the image in the obtained image recorded material to produce a laminated body.

[0060] The reason for achieving the improved boiling resistance of the laminate is believed to be that, when the pretreatment liquid and ink are sequentially applied to an impermeable substrate to record an image, the crosslinking agent in the pretreatment liquid crosslinks the components of the ink (e.g., a resin having a carboxyl group), and the inclusion of a nonionic urethane resin in the pretreatment liquid results in a hydrophobic image. In other words, the inclusion of the hydrophobic image in the laminate is believed to suppress water absorption by the laminate during a boiling treatment (i.e., the boiling resistance of the laminate is improved).

[0061] The excellent flexibility of the image in the laminate (i.e., its ability to conform to deformation of the non-permeable substrate) is believed to contribute to the aforementioned boiling resistance effect. This excellent flexibility of the image (i.e., its ability to conform to deformation of the non-permeable substrate) is believed to be due to the presence of a urethane resin in the pretreatment liquid.

[0062] As described above, the nonionic urethane resin in the pretreatment liquid is considered to improve the hydrophobicity of the image due to its nonionicity and to improve the flexibility of the image due to its being a urethane resin, thereby improving the boiling resistance of the laminate.

[0063] Hereinafter, each component that may be contained in the pretreatment liquid will be described.

[0064] <Water>

[0065] The pretreatment liquid of the present invention contains water.

[0066] The water content is preferably 50% by mass or more, more preferably 60% by mass or more, based on the total amount of the pretreatment liquid.

[0067] The upper limit of the water content depends on the amounts of other components, but is preferably 90% by mass or less, more preferably 80% by mass or less, based on the total amount of the pretreatment liquid.

[0068] <Coagulant>

[0069] The pretreatment liquid of the present invention contains at least one coagulant.

[0070] When a pretreatment liquid and an inkjet ink are sequentially applied to a non-permeable substrate to record an image, the aggregating agent in the pretreatment liquid aggregates the components in the inkjet ink, which contributes to improved image quality.

[0071] As the coagulant, for example, the coagulants described in paragraphs 0122 to 0130 of International Publication No. 2020 / 195360 can be used.

[0072] -Organic acid-

[0073] Examples of the organic acid include organic compounds having an acidic group.

[0074] Examples of the acidic group include a phosphoric acid group, a phosphonic acid group, a phosphinic acid group, a sulfuric acid group, a sulfonic acid group, a sulfinic acid group, and a carboxyl group.

[0075] Among these, from the viewpoint of the aggregation speed of the ink, the acidic group is preferably a phosphoric acid group or a carboxyl group, and more preferably a carboxyl group.

[0076] It is preferred that at least a part of the acidic groups be dissociated in the pretreatment liquid.

[0077] Examples of the organic compound having a carboxyl group include (meth)acrylic acid, poly(meth)acrylic acid, acetic acid, formic acid, benzoic acid, glycolic acid, malonic acid, malic acid (preferably DL-malic acid), maleic acid, succinic acid, glutaric acid, pimelic acid, adipic acid, fumaric acid, citric acid, tartaric acid, phthalic acid, 4-methylphthalic acid, lactic acid, pyrrolidonecarboxylic acid, pyronecarboxylic acid, pyrrolecarboxylic acid, furancarboxylic acid, pyridinecarboxylic acid, coumaric acid, thiophenecarboxylic acid, and nicotinic acid.

[0078] Among these, from the viewpoint of the aggregation speed of the ink, the organic compound having a carboxyl group is preferably a divalent or higher-valent carboxylic acid (hereinafter also referred to as a polyvalent carboxylic acid), and more preferably a dicarboxylic acid.

[0079] Specifically, the polycarboxylic acid is preferably malonic acid, malic acid, maleic acid, succinic acid, glutaric acid, pimelic acid, adipic acid, fumaric acid, tartaric acid, 4-methylphthalic acid or citric acid, and more preferably malonic acid, malic acid, tartaric acid, succinic acid, glutaric acid, pimelic acid, adipic acid or citric acid.

[0080] The organic acid preferably has a low pKa (eg, 1.0 to 5.0). Thus, contact with an organic acid with a lower pKa can reduce the surface charge of particles such as pigments and resin particles in the ink stabilized by weakly acidic functional groups such as carboxyl groups, thereby reducing dispersion stability.

[0081] The organic acid preferably has a low pKa, high solubility in water, and a valence of 2 or more. Furthermore, the organic acid more preferably has a high buffering capacity in a pH region lower than the pKa of the functional group (e.g., carboxyl group) that stabilizes particle dispersion in the ink.

[0082] -Polyvalent Metal Compounds-

[0083] Examples of the polyvalent metal compound include polyvalent metal salts.

[0084] Examples of the polyvalent metal salt include organic acid polyvalent metal salts and inorganic acid polyvalent metal salts.

[0085] As the organic acid polyvalent metal salt, polyvalent metal salts of the above-mentioned organic acids (for example, formic acid, acetic acid, benzoic acid, etc.) are preferred.

[0086] As the inorganic acid polyvalent metal salt, a nitrate polyvalent metal salt, a hydrochloric acid polyvalent metal salt or a thiocyanate polyvalent metal salt is preferable.

[0087] Examples of polyvalent metal salts include salts of alkaline earth metals of Group 2 of the periodic table (e.g., magnesium and calcium), salts of transition metals of Group 3 of the periodic table (e.g., lanthanum), salts of metals of Group 13 of the periodic table (e.g., aluminum), and salts of lanthanide elements (e.g., neodymium).

[0088] As the polyvalent metal salt, a calcium salt, a magnesium salt or an aluminum salt is preferred, and a calcium salt or a magnesium salt is more preferred.

[0089] As the polyvalent metal compound, an organic acid polyvalent metal salt is preferred, and an organic acid calcium salt or an organic acid magnesium salt is more preferred.

[0090] It is preferred that at least a portion of the polyvalent metal compound is dissociated into polyvalent metal ions and counter ions in the pretreatment liquid.

[0091] -Metal Complex-

[0092] The metal complex may contain at least one selected from the group consisting of zirconium, aluminum, and titanium as a metal element.

[0093] The metal complex is preferably a metal complex containing at least one ligand selected from the group consisting of acetate, acetylacetonate, methyl acetoacetate, ethyl acetoacetate, octanediol, butoxyacetylacetone, lactate, lactate ammonium salt, and triethanolamine.

[0094] The metal complex can be a commercially available product. Various organic ligands, particularly various multidentate ligands capable of forming metal chelate catalysts, are commercially available. Therefore, the metal complex can be a metal complex prepared by combining a commercially available organic ligand and a metal.

[0095] The content of the coagulant in the pretreatment liquid is preferably 0.1 to 40% by mass, more preferably 0.1 to 30% by mass, further preferably 1 to 20% by mass, and even more preferably 1 to 10% by mass, relative to the total amount of the pretreatment liquid.

[0096] From the viewpoint of further improving the boiling resistance of the laminate, the coagulant preferably contains at least one selected from the group consisting of organic acids and polyvalent metal salts of organic acids as polyvalent metal compounds.

[0097] In this case, the total amount of the organic acid and the organic acid polyvalent metal salt is preferably 50 to 100% by mass, more preferably 60 to 100% by mass, and even more preferably 80 to 100% by mass in the total amount of the coagulant.

[0098] From the viewpoint of further improving the boiling resistance of the laminate, the coagulant preferably further contains an organic acid.

[0099] In this case, the content of the organic acid in the total amount of the coagulant is preferably 50% by mass to 100% by mass, more preferably 60% by mass to 100% by mass, and even more preferably 80% by mass to 100% by mass.

[0100] <Nonionic urethane resin>

[0101] The pretreatment liquid of the present invention contains at least one nonionic urethane resin.

[0102] As described above, the nonionic urethane resin contributes to improving the boiling resistance of the laminate.

[0103] Specifically, as described above, the nonionic urethane resin improves the hydrophobicity of the image due to its nonionic nature (i.e., lack of ionicity). Furthermore, the urethane resin improves the flexibility of the resulting image (i.e., its ability to conform to deformation of an impermeable substrate). As a result of the improved hydrophobicity and flexibility of the image, the boiling resistance of the laminate is improved.

[0104] In the present invention, the nonionic urethane resin refers to a urethane resin that does not have ionicity (ie, anionicity or cationicity).

[0105] In the present invention, the urethane resin refers to a polymer containing a urethane bond.

[0106] The urethane resin is synthesized by, for example, a reaction between a diol compound and a diisocyanate compound.

[0107] For details of the diol compound and the diisocyanate compound, reference can be made to paragraphs 0031 to 0036 of, for example, JP-A-2001-247787.

[0108] Among them, the nonionic urethane resin is preferably a polyester urethane resin having an ester bond in the main chain, a polycarbonate urethane resin having a carbonate bond in the main chain, or a polyether urethane resin having an ether bond in the main chain.

[0109] The nonionic urethane resin may be a water-soluble urethane resin dissolved in water, or may be urethane resin particles dispersed in water.

[0110] Among these, the nonionic urethane resin is preferably urethane resin particles from the viewpoint of improving the strength of a layer obtained by applying the pretreatment liquid (hereinafter also referred to as a pretreatment layer).

[0111] When the nonionic urethane resin is in the form of urethane resin particles, the average particle size of the nonionic urethane resin is preferably 1 nm to 200 nm, more preferably 3 nm to 200 nm, and even more preferably 50 nm to 150 nm, from the perspective of storage stability of the pretreatment solution. The average particle size can be determined by measuring the volume average particle size using a particle size distribution analyzer, such as the "NANOTRAC UPA-EX150" manufactured by Nikkiso Co., Ltd., using a dynamic light scattering method.

[0112] The weight average molecular weight of the nonionic urethane resin is not particularly limited, but is preferably 1,000 to 300,000, more preferably 2,000 to 200,000, and even more preferably 10,000 to 150,000.

[0113] In the present invention, the weight average molecular weight (Mw) is measured by gel permeation chromatography (GPC). In GPC, HLC-8220GPC (manufactured by Tosoh Corporation) is used, and TSKgeL SuperHZM-H, TSKgeL SuperHZ4000, and TSKgel SuperHZ2000 (all product names manufactured by Tosoh Corporation) are used as columns and three are connected in series, and THF (tetrahydrofuran) is used as an eluent. In addition, as conditions, the sample concentration is set to 0.45% by mass, the flow rate is set to 0.35 ml / min, the sample injection amount is set to 10 μl, the measurement temperature is set to 40°C, and a differential refractive index detector is used. In addition, a calibration curve is prepared using 8 samples of "standard sample TSK standard, polystyrene (polystyrene)" manufactured by Tosoh Corporation: "F-40", "F-20", "F-4", "F-1", "A-5000", "A-2500", "A-1000", and "n-propylbenzene".

[0114] From the viewpoint of further improving the boiling resistance of the laminate, the glass transition temperature of the nonionic urethane resin is preferably -55°C to 50°C, more preferably -55°C to 20°C, and even more preferably -55°C to 0°C.

[0115] In the present invention, the glass transition temperature is measured using a differential scanning calorimeter, for example, "DSC-60" manufactured by Shimadzu Corporation.

[0116] From the perspective of further improving the boiling resistance of the laminate, the elongation at break of the nonionic urethane resin is preferably 300% to 1300%, more preferably 600% to 1300%. A nonionic urethane resin with an elongation at break of 300% to 1300% can reduce the internal stress generated by the boiling treatment, further improving the boiling resistance of the laminate.

[0117] In the present invention, the elongation at break is measured by the following method.

[0118] An aqueous solution or dispersion of a nonionic urethane resin was added to a Teflon (registered trademark) container having a bottom area of ​​50 mm x 100 mm and a height of 30 mm. The mixture was dried at 25°C for 24 hours and then at 80°C for 6 hours to obtain a resin film having a thickness of 500 μm. A 10 mm x 50 mm sample was cut from the resin film and subjected to a tensile test using a precision universal testing machine (product name "Autograph AG-IS", manufactured by Shimadzu Corporation). The elongation at break was measured in accordance with JIS K6251:2017.

[0119] The nonionic urethane resin may be a commercially available product. Examples of the commercially available product include the SUPERFLEX series manufactured by DKS Co. Ltd. and the PUE series manufactured by Murayama Chemical Laboratory.

[0120] The content of the nonionic urethane resin is preferably 1% by mass to 25% by mass, more preferably 5% by mass to 20% by mass, and even more preferably 5% by mass to 15% by mass, relative to the total amount of the pretreatment liquid.

[0121] The pretreatment liquid may contain a resin other than the nonionic urethane resin.

[0122] The ratio of the nonionic urethane resin to the total amount of resin components (i.e., nonionic urethane resin and resins other than nonionic urethane resin) in the pretreatment liquid is preferably 50% to 100% by mass, more preferably 80% to 100% by mass, and even more preferably 90% to 100% by mass.

[0123] <Crosslinking Agent>

[0124] The pretreatment liquid of the present invention contains at least one cross-linking agent.

[0125] In the present invention, the cross-linking agent refers to a compound having at least one cross-linking group.

[0126] Examples of the crosslinking group in the crosslinking agent include a carbodiimide group, an oxazoline group, an aziridine group (also known as an ethyleneimine group), an epoxy group, an isocyanate group, an aldehyde group, an N-methylol group, an acryloyl group, a vinyl sulfone group, an active halogen group, a glyoxal group, and a group having a melamine structure.

[0127] The cross-linking agent preferably contains a compound having at least one of a carbodiimide group and an oxazoline group.

[0128] Thereby, the boiling resistance of the laminate can be further improved.

[0129] Specific examples of the cross-linking agent which is a compound having a carbodiimide group include carbodiimide, N,N'-dimethylcarbodiimide, N-ethyl,N'-isopropylcarbodiimide, N,N'-diisopropylcarbodiimide, N,N'-dicyclohexylcarbodiimide, N,N'-diphenylcarbodiimide, N,N'-diacetylcarbodiimide, N,N'-bis(2-propylene)-carbodiimide, N,N'-dipyrrolidinylcarbodiimide, N,N'-diethoxycarbodiimide, bis(trimethylsilyl)carbodiimide, 1-cyclohexyl-3-(2-morpholinoethyl)carbodiimide meso-p-toluenesulfonate, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, and calcium cyanamide.

[0130] As the compound having a carbodiimide group, a commercially available product can also be used.

[0131] Examples of commercially available compounds having a carbodiimide group include Carbodilite V-02, Carbodilite SV-02, Carbodilite V-02-L2, Carbodilite V-04, Carbodilite V-06, Carbodilite E-01, Carbodilite E-02, Carbodilite E-03A, and Carbodilite SW-12G manufactured by Nisshinbo Chemical Inc.

[0132] Examples of the cross-linking agent, which is a compound having an oxazoline group, include 2-oxazoline, 2-methyl-2-oxazoline, 2-ethyl-2-oxazoline, 2-(n-propyl)-2-oxazoline, 2-(isopropyl)-2-oxazoline, 2-cyclohexyl-2-oxazoline, 2-phenyl-2-oxazoline, 2-pyrrolidinyl-2-oxazoline, 2-acetyl-2-oxazoline, 2-(2-propenyl)-2-oxazoline, 4,5-dimethyl-2-oxazoline, 2,4,4-trimethyl-2-oxazoline, 5-phenyl-2-(2-propynylamino)-2-oxazoline-4-one, and 4-ethoxymethylene-2-phenyl-2-oxazoline-5-one.

[0133] As the compound having an oxazoline group, a commercially available product can also be used.

[0134] Examples of commercially available compounds having an oxazoline group include EPOCROS series K-1010E, K-2010E, K-1020E, K-2020E, K-1030E, K-2030E, WS-300, WS-500, WS-700, and RPS-1005 manufactured by Nippon Shokubaiko, Ltd.

[0135] Examples of the crosslinking agent which is a compound having an epoxy group include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, diethylene glycol diglycidyl ether, dipropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and trimethylolpropane triglycidyl ether.

[0136] As the compound having an epoxy group, a commercially available product can also be used.

[0137] Examples of commercially available products of the compound having an epoxy group include Denacol EX-321, Denacol EX-821, Denacol EX-830, Denacol EX-850, and Denacol EX-851 manufactured by Nagase ChemteX Corporation.

[0138] Examples of the cross-linking agent that is a compound having an aziridine group (also known as an ethyleneimine group) include CHEMITITE PZ-33 and CHEMITITE DZ-22E manufactured by Nippon Shokubai Co., Ltd.

[0139] The content of the crosslinking agent is preferably 1.0 to 80% by mass, more preferably 2.0 to 60% by mass, further preferably 2.0 to 50% by mass, and even more preferably 2.5 to 50% by mass, relative to the total amount of the nonionic urethane resin.

[0140] When the content of the crosslinking agent is 1.0% by mass or more relative to the total amount of the nonionic urethane resin, the boiling resistance of the laminate is further improved. This is presumably because the crosslinking agent functions more effectively.

[0141] The boiling resistance of the laminate is further improved when the crosslinking agent content is 80% by mass or less relative to the total amount of the nonionic urethane resin. This is believed to be because the resulting image has improved flexibility (i.e., conformability to non-permeable substrates).

[0142] When the content of the cross-linking agent is 80% by mass or less relative to the total amount of the nonionic urethane resin, the storage stability of the pretreatment liquid is further improved.

[0143] The content of the crosslinking agent is preferably 0.10 to 10.00 mass %, more preferably 0.10 to 8.00 mass %, further preferably 0.10 to 5.00 mass %, further preferably 0.20 to 5.00 mass %, further preferably 0.25 to 5.00 mass % relative to the total amount of the pretreatment liquid.

[0144] When the content of the crosslinking agent is 0.10% by mass or more relative to the total amount of the pretreatment liquid, the boiling resistance of the laminate is further improved. This is presumably because the crosslinking agent acts more effectively.

[0145] The boiling resistance of the laminate is further improved when the crosslinking agent content is 10.00 mass % or less relative to the total amount of the pretreatment liquid. This is believed to be because the flexibility of the resulting image (i.e., conformability to non-permeable substrates) is further improved.

[0146] When the content of the cross-linking agent is 10.00% by mass or less relative to the total amount of the pre-treatment liquid, the storage stability of the pre-treatment liquid is further improved.

[0147] <Organic Solvents>

[0148] The pretreatment liquid of the present invention may contain at least one organic solvent.

[0149] The type of organic solvent is not limited, and examples thereof include:

[0150] Monoalcohols with 1 to 4 carbon atoms;

[0151] Diols such as 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, 2-butene-1,4-diol, 2-ethyl-1,3-hexanediol, 2-methyl-2,4-pentanediol, 1,2-octanediol, 1,2-hexanediol, 1,2-pentanediol, and 4-methyl-1,2-pentanediol;

[0152] Triols such as glycerol, 1,2,6-hexanetriol, and trimethylolpropane;

[0153] Alkylene glycols such as ethylene glycol and propylene glycol;

[0154] Alkylene glycol monoalkyl ethers such as ethylene glycol monoalkyl ether and propylene glycol monoalkyl ether;

[0155] Polyalkylene glycols such as diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, dipropylene glycol, and polyoxyethylene polyoxypropylene glycol;

[0156] Polyalkylene glycol ethers such as diethylene glycol monoalkyl ether, triethylene glycol monoalkyl ether, tripropylene glycol monoalkyl ether, and polyoxypropylene glycerol ether;

[0157] 2-pyrrolidone, N-methyl-2-pyrrolidone;

[0158] wait.

[0159] The content of the organic solvent is preferably 1% by mass to 20% by mass, more preferably 3% by mass to 10% by mass, based on the total amount of the pretreatment liquid.

[0160] <Surfactant>

[0161] The pretreatment liquid of the present invention may contain at least one surfactant.

[0162] The type of surfactant is not particularly limited and may be any of anionic surfactants, cationic surfactants, betaine-based surfactants, and nonionic surfactants. Examples of surfactants include acrylic surfactants, fluorine-based surfactants, and silicone-based surfactants.

[0163] The content of the surfactant is preferably 0.1% by mass to 5% by mass, more preferably 0.2% by mass to 1% by mass, relative to the total amount of the pretreatment liquid.

[0164] <Other ingredients>

[0165] The pretreatment liquid of the present invention may contain other components besides the above-mentioned components as needed.

[0166] Other components that may be contained in the pretreatment liquid include well-known additives such as solid wetting agents, colloidal silica, inorganic salts, anti-fading agents, emulsion stabilizers, penetration enhancers, ultraviolet absorbers, preservatives, mildew inhibitors, pH adjusters, viscosity adjusters, rust inhibitors, chelating agents, and water-soluble polymer compounds (for example, the water-soluble polymer compounds described in paragraphs 0026 to 0080 of Japanese Patent Application Publication No. 2013-001854).

[0167] <Physical properties>

[0168] The pH of the pretreatment liquid is preferably 2.0 to 7.0, more preferably 2.0 to 4.0. The pH is measured at 25° C. using a pH meter, for example, a pH meter manufactured by DKK-TOA CORPORATION (model “HM-31”).

[0169] From the perspective of coating properties of the pretreatment liquid, the viscosity of the pretreatment liquid is preferably 0.5 to 10 mPa·s, more preferably 1 to 5 mPa·s. The viscosity is a value measured at 25°C using a viscometer. The viscosity is measured at 25°C using a viscometer, for example, a TV-22 viscometer manufactured by Toki Sangyo Co., Ltd.

[0170] The surface tension of the pretreatment liquid is preferably 60 mN / m or less, more preferably 20 mN / m to 50 mN / m, and even more preferably 30 mN / m to 45 mN / m. The surface tension is a value measured at a temperature of 25°C. The surface tension is measured at 25°C using a surface tensiometer, for example, an automatic surface tensiometer manufactured by Kyowa Interface Science Co., Ltd. (product name "CBVP-Z"), by the plate method.

[0171] 〔Ink Group〕

[0172] The ink set of the present invention is an ink set for inkjet recording on non-permeable substrates, comprising:

[0173] The aforementioned pretreatment solution of the present invention; and

[0174] Inkjet ink (hereinafter also referred to simply as "ink") contains water, a pigment, and a resin having a carboxyl group.

[0175] Since the ink set of the present invention contains the aforementioned pre-treatment liquid of the present invention, it has the same effects as those of the aforementioned pre-treatment liquid of the present invention.

[0176] <Ink>

[0177] The ink set of the present invention includes an ink containing water, a pigment, and a resin having a carboxyl group.

[0178] The ink set of the present invention may contain only one type of ink or two or more types of ink.

[0179] (water)

[0180] The ink contains water.

[0181] The water content is preferably 10% by mass or more, more preferably 20% by mass or more, further preferably 30% by mass or more, and particularly preferably 50% by mass or more, relative to the total amount of the ink.

[0182] The upper limit of the water content relative to the total amount of the ink is appropriately determined depending on the contents of other components, and is, for example, 99% by mass, preferably 95% by mass, and more preferably 90% by mass.

[0183] (Resin having a carboxyl group)

[0184] The ink contains at least one resin having a carboxyl group.

[0185] -Urethane resin having a carboxyl group-

[0186] The resin having a carboxyl group contained in the ink preferably includes a urethane resin having a carboxyl group.

[0187] The carboxyl group-containing urethane resin that may be contained in the ink is preferably a polyester urethane resin having a carboxyl group and an ester bond in the main chain, a polycarbonate urethane resin having a carboxyl group and a carbonate bond in the main chain, or a polyether urethane resin having a carboxyl group and an ether bond in the main chain.

[0188] The urethane resin having a carboxyl group that may be contained in the ink may be a water-soluble urethane resin or a water-insoluble urethane resin (ie, urethane resin particles).

[0189] Among these, the urethane resin is preferably urethane resin particles from the viewpoint of improving the strength of the layer formed by the ink.

[0190] When the urethane resin having a carboxyl group that may be contained in the ink is urethane resin particles, the average particle size of the urethane resin particles is preferably 1 nm to 200 nm, more preferably 3 nm to 200 nm, and even more preferably 5 nm to 50 nm from the viewpoint of ejection stability.

[0191] The average particle size of the urethane resin particles in the ink can be measured by the same method as that for the average particle size of the urethane resin particles in the pretreatment liquid.

[0192] The weight average molecular weight (Mw) of the urethane resin having a carboxyl group which may be contained in the ink is not particularly limited, but is preferably 1,000 to 300,000, more preferably 2,000 to 200,000, and even more preferably 10,000 to 150,000.

[0193] The weight average molecular weight of the urethane resin having a carboxyl group that may be contained in the ink can be measured by the same method as that for measuring the weight average molecular weight of the nonionic urethane resin in the pretreatment liquid.

[0194] The urethane resin having a carboxyl group that may be contained in the ink may be a commercially available product.

[0195] Examples of commercially available products include SUPERFLEX series manufactured by DKS Co. Ltd., PERMARIN UA series and UCOAT series manufactured by SANYO CHEMICAL INDUSTRIES, LTD., TAKELAC series manufactured by Mitsui Chemicals, Inc., and PUE series manufactured by Murayama Institute of Chemistry.

[0196] The content of the urethane resin having a carboxyl group that can be contained in the ink is preferably 1 to 25% by mass, more preferably 2 to 20% by mass, and even more preferably 5 to 20% by mass, based on the total amount of the ink.

[0197] -Pigment dispersing resin having carboxyl groups-

[0198] The resin having a carboxyl group contained in the ink may include a pigment dispersing resin having a carboxyl group.

[0199] Examples of the pigment-dispersing resin having a carboxyl group include pigment-dispersing resins having a carboxyl group among the pigment-dispersing resins described later.

[0200] (Content of resin having carboxyl group)

[0201] The content of the resin having a carboxyl group in the ink is preferably 1.0 to 10.0% by mass, more preferably 3.0 to 9.0% by mass, and even more preferably 4.0 to 8.0% by mass, based on the total mass of the ink.

[0202] For example, when the resin having a carboxyl group in the ink is a urethane resin having a carboxyl group and a pigment dispersion resin having a carboxyl group, the content of the resin having a carboxyl group in the ink referred to here is the total amount of the urethane resin having a carboxyl group and the pigment dispersion resin having a carboxyl group.

[0203] (pigment)

[0204] Ink contains at least one pigment.

[0205] The pigment contained in the ink may be a white pigment or a coloring pigment.

[0206] The ink may be a white ink containing a white pigment or a colored ink containing a colored pigment.

[0207] In the present invention, the coloring pigment refers to a color pigment or a black pigment.

[0208] In the present invention, the colored ink refers to a color ink (for example, cyan ink, magenta ink, yellow ink, etc.) or a black ink.

[0209] From the viewpoint of the concealability of the resulting image (ie, the property of shielding the surface of the non-permeable substrate, etc., on which the image is recorded), the ink is preferably a white ink containing a white pigment.

[0210] Here, the concealability of an image refers to a property of shielding a surface on which an image is recorded (for example, the surface of an impermeable substrate, the surface of an image formed as a base, etc.).

[0211] (white pigment)

[0212] Examples of the white pigment include inorganic pigments such as titanium dioxide, barium sulfate, calcium carbonate, silicon dioxide, zinc oxide, zinc sulfide, mica, talc, and pearl.

[0213] Among them, the white pigment is preferably titanium dioxide, barium sulfate, calcium carbonate or zinc oxide, and more preferably titanium dioxide.

[0214] From the perspective of concealability, the average primary particle size of the white pigment is preferably 150 nm or more, more preferably 200 nm or more. Furthermore, from the perspective of ink ejection properties, the average primary particle size of the white pigment is preferably 400 nm or less, more preferably 350 nm or less.

[0215] In the present invention, the average primary particle size of the white pigment is a value measured using a transmission electron microscope (TEM). Specifically, it is a value obtained by selecting 50 random white pigments present in the field of view observed by TEM, measuring the primary particle sizes of the 50, and averaging the values. As a transmission electron microscope, a transmission electron microscope 1200EX manufactured by JEOL Ltd. can be used.

[0216] From the viewpoint of image density and ejection properties, the content of the white pigment is preferably 2 to 25% by mass, more preferably 5 to 25% by mass, and even more preferably 10 to 20% by mass relative to the total amount of ink.

[0217] Furthermore, the ink may contain a coloring pigment instead of or in addition to the white pigment.

[0218] When the ink contains a coloring pigment, the type and content of the coloring pigment can be referred to the section of the second ink described later.

[0219] (Pigment dispersion resin)

[0220] The ink may also contain at least one pigment dispersing resin.

[0221] In the present invention, the pigment-dispersing resin refers to a resin having a function of dispersing a pigment.

[0222] The pigment dispersing resin may be a random copolymer or a block copolymer.

[0223] Also, the pigment dispersion resin may have a cross-linked structure.

[0224] The ink can be prepared using a pigment dispersion containing a pigment and a pigment dispersing resin.

[0225] The pigment dispersing resin is preferably a random copolymer.

[0226] The random copolymer preferably contains structural units derived from a hydrophobic monomer and structural units derived from a monomer containing an anionic group (hereinafter referred to as an "anionic group-containing monomer"). From the perspective of dispersion stability, the ratio of structural units x derived from the hydrophobic monomer to structural units y derived from the anionic group-containing monomer (x:y) is preferably 8:1 to 1:1.

[0227] The structural unit derived from the hydrophobic monomer contained in the random copolymer may be only one type or two or more types.

[0228] The structural unit derived from the anionic group-containing monomer contained in the random copolymer may be only one type or two or more types.

[0229] The hydrophobic monomer preferably comprises a monomer having a hydrocarbon group having 4 or more carbon atoms, more preferably comprises an ethylenically unsaturated monomer having a hydrocarbon group having 4 or more carbon atoms, and even more preferably comprises a (meth)acrylate having a hydrocarbon group having 4 or more carbon atoms. The hydrocarbon group may be any of a chain hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. The number of carbon atoms in the hydrocarbon group is more preferably 6 or more, and even more preferably 10 or more. The upper limit of the number of carbon atoms in the hydrocarbon group is, for example, 20.

[0230] Examples of (meth)acrylates having a chain hydrocarbon group with 4 or more carbon atoms include n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, lauryl (meth)acrylate, and octadecyl (meth)acrylate. The chain hydrocarbon group preferably has 6 or more carbon atoms, further preferably 8 or more, and particularly preferably 12 or more. Among these, the ethylenically unsaturated monomer having a chain hydrocarbon group with 4 or more carbon atoms is preferably lauryl (meth)acrylate or octadecyl (meth)acrylate.

[0231] Examples of the (meth)acrylate having an alicyclic hydrocarbon group having 4 or more carbon atoms include (bicyclo〔2.2.1〕heptyl-2-(meth)acrylate, 1-adamantyl (meth)acrylate, 2-adamantyl (meth)acrylate, 3-methyl-1-adamantyl (meth)acrylate, 3,5-dimethyl-1-adamantyl (meth)acrylate, 3-ethyladamantyl (meth)acrylate, 3-methyl-5-ethyl-1-adamantyl (meth)acrylate, 3,5,8-triethyl-1-adamantyl (meth)acrylate, 3,5-dimethyl-8-ethyl-1-adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, and 3,5-dimethyl-1-adamantyl (meth)acrylate. 2-ethyl-2-adamantyl (meth)acrylate, 3-hydroxy-1-adamantyl (meth)acrylate, octahydro-4,7-methyleneinden-5-yl (meth)acrylate, octahydro-4,7-methyleneinden-1-ylmethyl (meth)acrylate, 1-methyl (meth)acrylate, tricyclodecyl (meth)acrylate, 3-hydroxy-2,6,6-trimethyl-bicyclo[3.1.1]heptyl (meth)acrylate, 3,7,7-trimethyl-4-hydroxy-bicyclo[4.1.0]heptyl (meth)acrylate, (n-)bornyl (meth)acrylate, isobornyl (meth)acrylate, 2,2,5-trimethylcyclohexyl (meth)acrylate, and cyclohexyl (meth)acrylate. The alicyclic hydrocarbon group preferably has 6 or more carbon atoms. Among them, the ethylenically unsaturated monomer having an alicyclic hydrocarbon group having 4 or more carbon atoms is preferably isobornyl (meth)acrylate or cyclohexyl (meth)acrylate.

[0232] Examples of (meth)acrylates having an aromatic hydrocarbon group having 4 or more carbon atoms include 2-naphthyl (meth)acrylate, phenoxyethyl (meth)acrylate, and benzyl (meth)acrylate. Among these, benzyl (meth)acrylate is preferred as the ethylenically unsaturated monomer having an aromatic hydrocarbon group having 4 or more carbon atoms.

[0233] The hydrophobic monomer may further contain a (meth)acrylate having a hydrocarbon group having 1 to 3 carbon atoms.

[0234] Examples of the (meth)acrylate having a hydrocarbon group having 1 to 3 carbon atoms include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, and hydroxyethyl (meth)acrylate.

[0235] Among them, from the viewpoint of improving the dispersion stability of the white pigment, the structural unit derived from the hydrophobic monomer contained in the pigment dispersion resin preferably includes a structural unit derived from a (meth)acrylate having a chain hydrocarbon group with 4 or more carbon atoms and a structural unit derived from a (meth)acrylate having an aromatic hydrocarbon group with 4 or more carbon atoms.

[0236] Examples of the anionic group in the anionic group-containing monomer include a carboxyl group, a carboxyl group salt, a sulfo group, a sulfo group salt, a phosphoric acid group, a phosphoric acid group salt, a phosphonic acid group, and a phosphonic acid group salt.

[0237] Examples of the counter ion in the salt include alkali metal ions such as sodium ion, potassium ion, and lithium ion; alkaline earth metal ions such as calcium ion and magnesium ion; and ammonium ion.

[0238] Among them, the anionic group is preferably a carboxyl group or a salt of a carboxyl group.

[0239] Examples of the carboxyl group-containing monomer include (meth)acrylic acid, β-carboxyethyl acrylate, fumaric acid, itaconic acid, maleic acid, and crotonic acid.

[0240] From the viewpoint of dispersion stability, the anionic group-containing monomer is preferably (meth)acrylic acid or β-carboxyethyl acrylate, and more preferably (meth)acrylic acid.

[0241] The ratio of the content of the white pigment to the content of the pigment dispersion resin is preferably 1:0.04 to 1:3, more preferably 1:0.05 to 1:1, and even more preferably 1:0.05 to 1:0.5, based on mass.

[0242] From the viewpoint of dispersion stability, the acid value of the pigment dispersion resin is preferably 100 mgKOH / g or more, more preferably 120 mgKOH / g or more.

[0243] On the other hand, from the viewpoint of dispersion stability, the acid value of the pigment dispersion resin is preferably 300 mgKOH / g or less, more preferably 230 mgKOH / g or less.

[0244] When the ink contains a pigment dispersing resin, the content of the pigment dispersing resin is preferably 0.1 to 10% by mass, more preferably 0.3 to 5% by mass, and even more preferably 0.5 to 2.5% by mass, relative to the total amount of the ink.

[0245] (Organic Solvent)

[0246] The ink preferably contains an organic solvent.

[0247] This improves discharge stability.

[0248] The organic solvent contained in the coloring ink may be one kind or two or more kinds.

[0249] Examples of the organic solvent include the same organic solvents as those contained in the above-mentioned pretreatment liquid.

[0250] From the viewpoint of discharge stability, the organic solvent preferably contains at least one selected from the group consisting of alkylene glycols and alkylene glycol monoalkyl ethers.

[0251] The content of the organic solvent is preferably 10% by mass to 40% by mass, and more preferably 15% by mass to 30% by mass, relative to the total amount of the ink.

[0252] (additive)

[0253] The ink may contain additives such as a surfactant, a water-soluble resin, a co-sensitizer, an ultraviolet absorber, an antioxidant, an anti-fading agent, a conductive salt, and an alkaline compound as needed.

[0254] (physical properties)

[0255] From the viewpoint of improving discharge stability, the pH (25° C.) of the ink is preferably 7 to 10, more preferably 7.5 to 9.5. The pH of the colored ink can be measured by the same method as the pH of the pretreatment liquid.

[0256] The viscosity of the ink (30°C) is preferably 0.5 to 30 mPa·s, more preferably 2 to 20 mPa·s, preferably 2 to 15 mPa·s, and even more preferably 3 to 10 mPa·s. The viscosity of the color ink can be measured by the same method as the viscosity of the pretreatment liquid.

[0257] The surface tension (25° C.) of the ink is preferably 60 mN / m or less, more preferably 20 mN / m to 50 mN / m, and even more preferably 30 mN / m to 45 mN / m.

[0258] The surface tension can be measured by the same method as in the case of the pretreatment liquid.

[0259] <First Ink, Second Ink>

[0260] The ink set of the present invention may comprise:

[0261] The aforementioned white ink is an inkjet ink containing water, a white pigment, and a resin having a carboxyl group (hereinafter also referred to as "first ink"); and

[0262] The colored ink is an inkjet ink (hereinafter also referred to as "second ink") containing water, a colored pigment, and a resin having a carboxyl group.

[0263] In this case, the ink set may include two or more white inks, or may include two or more colored inks (for example, a combination of cyan ink, magenta ink, yellow ink, and black ink).

[0264] That is, one specific embodiment of the ink set of the present invention includes the pre-treatment liquid of the present invention, a first ink as a white ink, and a second ink as a colored ink.

[0265] The first ink as white ink is an inkjet ink containing water, a white pigment and a resin having a carboxyl group.

[0266] The second ink as the coloring ink is an inkjet ink containing water, a coloring pigment, and a resin having a carboxyl group.

[0267] Preferred aspects of the second ink are the same as those of the first ink (ie, white ink), except that the second ink contains a color pigment as an essential component.

[0268] For example, preferred aspects of the type and content of each component in the second ink are the same as preferred aspects of the type and content of each component in the first ink.

[0269] (Coloring Pigments)

[0270] The coloring pigment may be any of commercially available organic pigments and inorganic pigments.

[0271] Examples of coloring pigments include those described in "Encyclopedia of Pigments" edited by Seishiro Ito (published in 2000), "Industrial Organic Pigments" by W. Herbst and K. Hunger, and Japanese Patent Application Publication Nos. 2002-12607, 2002-188025, 2003-26978, and 2003-342503.

[0272] Furthermore, the coloring pigment may be a water-insoluble pigment that can be dispersed in water using a dispersant, or may be a self-dispersible pigment.

[0273] Self-dispersible pigments are pigments that can be dispersed in water without using a dispersant.

[0274] Self-dispersible pigments are compounds in which at least one selected from the group consisting of hydrophilic groups such as carbonyl, hydroxyl, carboxyl, sulfonyl, and phosphoric acid groups and salts thereof is chemically bonded to the surface of the pigment directly or via other groups.

[0275] The type of coloring pigment is not particularly limited, and examples thereof include cyan pigments, magenta pigments, yellow pigments, and black pigments.

[0276] From the viewpoint of image density and ejection properties of the second ink, the content of the color pigment is preferably 1 to 20 mass %, more preferably 1 to 15 mass %, and even more preferably 1 to 10 mass % relative to the total amount of the second ink.

[0277] [Image Recording Method]

[0278] The image recording method of the present invention comprises the following steps:

[0279] applying the pretreatment liquid of the present invention to the non-permeable substrate (hereinafter also referred to as "pretreatment liquid applying step"); and

[0280] An ink containing water, a pigment, and a resin having a carboxyl group (ie, inkjet ink, the same applies hereinafter) is applied by inkjet method to the area on the non-permeable substrate to which the pretreatment liquid has been applied (hereinafter also referred to as "ink applying step").

[0281] Since the image recording method of the present invention uses the aforementioned pre-treatment liquid of the present invention, the same effects as those of the aforementioned pre-treatment liquid of the present invention are achieved.

[0282] The ink used in the ink applying step has the same meaning as the ink described in the section of the ink set of the present invention, and preferred embodiments are also the same.

[0283] For example, the resin having a carboxyl group contained in the ink used in the ink applying step preferably includes a urethane resin having a carboxyl group.

[0284] Furthermore, from the viewpoint of concealability of the image, the ink used in the ink application step is preferably a white ink containing a white pigment.

[0285] The amount of crosslinking agent in the pretreatment solution applied to the non-permeable substrate (g / m 2 ) relative to the amount of the resin having a carboxyl group in the ink applied to the non-permeable substrate (g / m 2 ), preferably 0.3 mass % to 50.0 mass %, more preferably 1.0 mass % to 30.0 mass %, further preferably 1.0 mass % to 25.0 mass %, further preferably 1.0 mass % to 22.0 mass %.

[0286] Next, the amount of crosslinking agent applied to the pretreatment solution on the non-permeable substrate (g / m 2 ) relative to the amount of the resin having a carboxyl group in the ink applied to the non-permeable substrate (g / m 2 ) is also referred to as "amount ratio [crosslinking agent in pre-treatment liquid / resin having a carboxyl group in ink]".

[0287] When the addition ratio [crosslinking agent in the pretreatment liquid / resin having a carboxyl group in the ink] is 0.3 mass % or more, the boiling resistance of the laminate is further improved. This is presumably because the crosslinking agent functions more effectively.

[0288] When the crosslinking agent content relative to the total amount of the pretreatment liquid (crosslinking agent in the pretreatment liquid / carboxyl group-containing resin in the ink) is 50.0% by mass or less, the boiling resistance of the laminate is further improved. This is believed to be because the resulting image's flexibility (i.e., its ability to conform to non-permeable substrates) is further enhanced.

[0289] Hereinafter, each step of the image recording method of the present invention will be described.

[0290] <Pretreatment Liquid Application Step>

[0291] The pre-treatment liquid applying step is a step of applying the pre-treatment liquid in the ink set of the present invention (ie, the pre-treatment liquid of the present invention) to the non-permeable substrate.

[0292] (Impermeable substrate)

[0293] In the present invention, the impermeability of an impermeable substrate refers to a water absorption rate of 2.5% or less within 24 hours, as measured in accordance with ASTM D570-98 (2018). The unit "%" for water absorption is based on mass. The water absorption rate is preferably 1.0% or less, and more preferably 0.5% or less.

[0294] Examples of materials for the non-permeable substrate include glass, metals (e.g., aluminum, zinc, copper, etc.), and resins (e.g., polyvinyl chloride, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, nylon, acrylic resin, etc.).

[0295] The material of the impermeable substrate is preferably a resin. In other words, the impermeable substrate is preferably a resin substrate.

[0296] Among them, from the viewpoint of versatility, the material of the impermeable substrate is preferably polypropylene, polyethylene, polyethylene terephthalate, nylon, acrylic resin or polyvinyl chloride.

[0297] The shape of the impermeable substrate is preferably a sheet (film) or plate. Examples of such impermeable substrates include glass plates, metal plates, resin sheets (resin films), plastic-laminated paper, metal-laminated or vapor-deposited paper, and metal-laminated or vapor-deposited plastic sheets (plastic films).

[0298] Examples of the resin-made impermeable substrate include resin sheets (resin films), and specifically, flexible packaging materials for packaging food and the like, and floor guides for large retail stores.

[0299] Examples of the impermeable substrate include sheet-shaped (film-shaped) or plate-shaped impermeable substrates and textiles (woven fabrics) and nonwoven fabrics formed of impermeable fibers.

[0300] The thickness of the impermeable substrate is preferably 0.1 μm to 1,000 μm, more preferably 0.1 μm to 800 μm, and even more preferably 1 μm to 500 μm.

[0301] The non-permeable substrate may be subjected to a hydrophilic treatment. Examples of hydrophilic treatments include, but are not limited to, corona treatment, plasma treatment, flame treatment, heat treatment, abrasion treatment, light irradiation treatment (e.g., UV treatment), and flame treatment. Corona treatment can be performed, for example, using a corona master (product name "PS-10S," manufactured by Shinko Electric & Instrumentation Co., Ltd.). The conditions for the corona treatment can be appropriately selected depending on the type of non-permeable substrate.

[0302] The non-permeable substrate may be a transparent non-permeable substrate.

[0303] Here, transparency means that the transmittance of visible light with a wavelength of 400 nm to 700 nm is 80% or more (preferably 90% or more).

[0304] When the impermeable substrate is transparent, the image can be easily visually recognized from the image non-recording surface side of the impermeable substrate through the impermeable substrate.

[0305] For example, when the non-permeable substrate is a transparent non-permeable substrate, when a pre-treatment liquid, a second ink as a colored ink, and an ink as a white ink are sequentially applied to the non-permeable substrate to record an image, it is easy to visually recognize the colored image (e.g., a pattern image such as characters or graphics) with a white image (e.g., a solid image) as a background from the image non-recording surface side of the non-permeable substrate through the non-permeable substrate.

[0306] (Applying a pretreatment solution)

[0307] The method for applying the pretreatment liquid is not particularly limited, and examples thereof include known methods such as a coating method, a dipping method, and an inkjet recording method.

[0308] Examples of the coating method include known coating methods using a bar coater, an extrusion die coater, an air doctor coater, a blade coater, a rod coater, a knife coater, a squeeze coater, and a reverse roll coater.

[0309] The amount of the pretreatment liquid applied to the non-permeable substrate is preferably 0.5 g / m 2 ~5.0g / m 2 , more preferably 1.0 g / m 2 ~4.0g / m 2 .

[0310] (Heating and drying of pretreatment liquid)

[0311] The pre-treatment liquid applying step may include a step of applying the pre-treatment liquid to the non-permeable substrate and a step of heating and drying the pre-treatment liquid applied to the non-permeable substrate.

[0312] As a device for heating and drying the pretreatment liquid, there can be mentioned a known heating device such as a heater, a known air blowing device such as a dryer, and a device in combination thereof.

[0313] Examples of methods for heat-drying the pretreatment liquid include a method of heating the non-permeable substrate from the side opposite to the side to which the pretreatment liquid is applied using a heater, a method of blowing warm air or hot air onto the side to which the pretreatment liquid is applied, a method of heating the non-permeable substrate from the side to which the pretreatment liquid is applied or from the side opposite to the side to which the pretreatment liquid is applied using an infrared heater, and a method of combining a plurality of these methods.

[0314] The heating temperature during heat drying of the pretreatment liquid is preferably 35° C. or higher, more preferably 40° C. or higher. The upper limit of the heating temperature is not particularly limited, but is preferably 100° C., more preferably 90° C., and even more preferably 70° C.

[0315] The heating drying time is not particularly limited, but is preferably 0.5 to 60 seconds, more preferably 0.5 to 20 seconds, and even more preferably 0.5 to 10 seconds.

[0316] <Ink application process>

[0317] The ink applying step is a step of applying ink by inkjet recording to the area on the non-permeable substrate to which the pre-treatment liquid has been applied.

[0318] Through this step, the components in the ink are aggregated on the non-permeable substrate by the action of the aggregating agent in the pre-treatment liquid, thereby forming an image.

[0319] (Applying ink)

[0320] The ink ejection method in the inkjet recording method is not particularly limited and can be any of the well-known methods, for example, a charge control method that utilizes electrostatic induction force to eject the ink, a drop-on-demand inkjet method (pressure pulse method) that utilizes the vibration pressure of a piezoelectric element, an acoustic inkjet method that converts an electrical signal into a sound beam and irradiates the ink to eject the ink using radiation pressure, and a thermal inkjet (Bubble Jet (registered trademark)) method that heats the ink to form bubbles and utilizes the generated pressure.

[0321] As an inkjet recording method, the method described in Japanese Patent Application Laid-Open No. 54-59936 can be particularly effectively utilized. In this inkjet recording method, the ink undergoes a rapid volume change upon exposure to thermal energy, and the force generated by this change in state causes the ink to be ejected from a nozzle. Another applicable inkjet recording method is the method described in paragraphs 0093 to 0105 of Japanese Patent Application Laid-Open No. 2003-306623.

[0322] Inkjet recording is performed by applying ink to a non-permeable substrate by ejecting the ink from the nozzles of an inkjet head.

[0323] As inkjet head methods, there are a reciprocating method in which a short serial head records while scanning in the width direction of the recording medium, and a linear method in which a line inkjet head is used in which recording elements are arranged corresponding to the entire area of ​​one side of the recording medium.

[0324] In the linear method, the image can be recorded across the entire surface of the recording medium by scanning it in a direction intersecting the arrangement of the recording elements. The linear method eliminates the need for a carriage or other transport system, such as the one used in the reciprocating method to scan short strips of inkjet heads. Furthermore, compared to the reciprocating method, the linear method eliminates the need for complex carriage movement and scanning control between the recording medium and the recording medium; only the recording medium needs to be moved. Therefore, the linear method can achieve faster image recording speeds compared to the reciprocating method.

[0325] The ink is preferably applied using an inkjet head having a resolution of 300 dpi or higher (more preferably 600 dpi or higher, and even more preferably 800 dpi or higher). Dpi is an abbreviation for dots per inch, and a linch is 2.54 cm.

[0326] From the viewpoint of obtaining a high-definition image, the ejection amount of the ink is preferably 1 pL (picoliter) to 10 pL, and more preferably 1.5 pL to 6 pL.

[0327] The amount of ink applied to the area of ​​the non-permeable substrate to which the pre-treatment liquid is applied is preferably 3.0 g / m 2 ~15.0g / m 2 , more preferably 5.0 g / m 2 ~12.0g / m 2 .

[0328] (heat drying)

[0329] The ink imparting process may include the following steps:

[0330] applying ink to the area of ​​the non-permeable substrate to which the pre-treatment liquid has been applied by inkjet; and

[0331] The applied ink is heated and dried.

[0332] The heat drying method is not particularly limited, and examples thereof include infrared (IR) drying, warm air drying, and heat drying using a heating device (eg, a heater, a hot plate, a heating furnace, etc.).

[0333] As the heat drying method, a method of combining two or more of these may be used.

[0334] Heat drying can be performed by heating the ink from at least one of the image recording surface side and the image non-recording surface side of the impermeable substrate.

[0335] The heating temperature during heat drying of the ink is preferably 35° C. or higher, more preferably 40° C. or higher, further preferably 50° C. or higher, and further preferably 60° C. or higher.

[0336] The upper limit of the heating temperature is not particularly limited, but is preferably 100°C, more preferably 90°C.

[0337] The heating time for heat drying the ink is not particularly limited, but is preferably 1 to 180 seconds, more preferably 1 to 120 seconds, and even more preferably 1 to 60 seconds.

[0338] <Implementation Method>

[0339] As an example of the image recording method of the present invention when using two or more colors of ink, there is an image recording method using the above-mentioned first ink (ie, white ink) and second ink (ie, colored ink).

[0340] The image recording method involved in this example includes the following steps:

[0341] applying the pretreatment solution of the present invention to the non-permeable substrate;

[0342] The first ink (ie, white ink) and the second ink (ie, colored ink) are applied by inkjet recording to the area on the non-permeable substrate to which the pre-treatment liquid has been applied.

[0343] The step of applying the pretreatment liquid to the non-permeable substrate is as described above.

[0344] According to the image recording method according to the present embodiment, a multi-color image can be recorded using the first ink (ie, white ink) and the second ink (ie, colored ink).

[0345] Examples of multi-color images include colored images (eg, pattern images such as characters and graphics) with a white image (eg, solid image) as a background.

[0346] Regarding the order of applying the first ink (ie, white ink) and the second ink (ie, colored ink), either one may be applied first.

[0347] For example, when the image is visually recognized from the image recording surface side, the first ink (ie, white ink) and the second ink (ie, colored ink) are applied in this order.

[0348] When the image is visually recognized through the impermeable substrate from the non-image recording side, the second ink (i.e., colored ink) and the first ink (i.e., white ink) are applied in this order. This results in a multi-color image in which, for example, a pattern image (such as text or graphics) recorded with the colored ink and a solid white image recorded with the white ink to obscure the pattern image are sequentially arranged on the impermeable substrate.

[0349] In the step of applying the first ink and the second ink, the method of applying the first ink and the second ink by the inkjet recording method is as described above.

[0350] Furthermore, the step of applying the first ink and the second ink may include the step of heating and drying the ink after applying at least one of the first ink and the second ink. Preferred conditions for heating and drying are as described above.

[0351] For example, as a method for this step, a method of sequentially applying the second ink (i.e., the colored ink), applying the first ink (i.e., the white ink), and drying can be mentioned. In this method, the second ink may be heated and dried between the application of the second ink and the application of the first ink. Heat drying may also be omitted.

[0352] [Method for producing laminate]

[0353] The method for producing the laminate of the present invention comprises the following steps:

[0354] An image recorded article comprising an impermeable substrate and an image disposed on the impermeable substrate is obtained by the image recording method of the present invention; and

[0355] The laminating substrate is laminated on the side of the image-recorded material on which the image is arranged to obtain a laminate.

[0356] Since the method for producing a laminate of the present invention includes the aforementioned image recording method of the present invention, the same effects as those of the aforementioned image recording method of the present invention are achieved. Specifically, a laminate having excellent boiling resistance can be obtained.

[0357] Regarding the steps for obtaining an image recorded object, reference can be made to the image recording method of the present invention.

[0358] The step of obtaining a laminate is a step of laminating a laminating substrate on the side of the image recorded material on which the image is arranged to obtain a laminate.

[0359] Lamination can be performed, for example, by laminating the laminating substrate to the side of the image-recorded article on which the image is arranged via another layer (e.g., an adhesive layer) and attaching the substrate, or by laminating the laminating substrate to the side of the image-recorded article on which the image is arranged using a laminator. In the latter case, a commercially available laminator can be used.

[0360] The lamination temperature during lamination is not particularly limited. For example, when the image recorded material and the lamination substrate are attached via another layer (e.g., an adhesive layer), the lamination temperature may be 20°C or higher. Furthermore, when using a laminator, the lamination roller temperature may be set within a range of 20°C to 80°C. The pressure force of the lamination roller pair may be appropriately selected as needed.

[0361] The lamination substrate is preferably a resin substrate.

[0362] The resin substrate is not particularly limited, and examples thereof include substrates made of thermoplastic resins.

[0363] Examples of the resin substrate include substrates obtained by molding a thermoplastic resin into a sheet shape.

[0364] The resin substrate preferably contains polypropylene, polyethylene terephthalate, nylon, polyethylene, or polyimide.

[0365] The shape of the resin substrate is not particularly limited, but a sheet-shaped resin substrate is preferred. The thickness of the resin substrate is preferably 10 μm to 200 μm, more preferably 10 μm to 100 μm.

[0366] In the step of obtaining the laminate, the laminating substrate may be laminated directly on the image-disposed side of the image recorded material or may be laminated via another layer (eg, an adhesive layer) thereon.

[0367] When the laminating substrate is directly laminated on the side of the image recorded material on which the image is arranged, lamination can be performed by a known method such as thermocompression bonding or thermal fusion bonding.

[0368] Furthermore, lamination of the laminating substrate to the image-disposed side of the image recorded material via the adhesive layer can be carried out, for example, by applying an adhesive to the image-disposed side of the image recorded material, placing the laminating substrate thereon, and then bonding the image recorded material and the laminating substrate together.

[0369] Furthermore, lamination on the side of the image recorded material on which the image is arranged via an adhesive layer can also be performed by a method such as extrusion lamination (ie, sandwich lamination).

[0370] The adhesive layer preferably contains isocyanate. When the adhesive layer contains isocyanate, the adhesion between the adhesive layer and the image is further improved, and thus the boiling resistance can be further improved.

[0371] [Visual Records]

[0372] The image recorded article of the present invention comprises an impermeable substrate and an image disposed on the impermeable substrate.

[0373] The image contains:

[0374] a pretreatment layer disposed on the non-permeable substrate and containing a coagulant, a nonionic urethane resin, and a cross-linking agent; and

[0375] The ink layer is disposed on the pretreatment layer and contains a pigment and a resin having a carboxyl group.

[0376] The image recorded article of the present invention can be produced by the image recording method of the present invention.

[0377] Therefore, a laminate having excellent boiling resistance can be produced.

[0378] Regarding the components in the pretreatment layer and the components in the ink layer, the components of the pretreatment liquid and the components of the ink described above can be appropriately referred to.

[0379] [Laminate]

[0380] The laminate of the present invention comprises:

[0381] The aforementioned image record of the present invention; and

[0382] The laminating substrate is laminated onto the image in the image recorded material.

[0383] The laminate of the present invention can be produced by the method for producing a laminate of the present invention.

[0384] Therefore, it has excellent boiling resistance.

[0385] Preferred embodiments of the lamination substrate are as described above.

[0386] Example

[0387] Hereinafter, the present invention will be described in more detail with reference to Examples. However, the present invention is not limited to the following Examples unless it departs from the gist of the present invention.

[0388] [Examples 1 to 27, Comparative Examples 1 to 5]

[0389] <Preparation of Pretreatment Liquid>

[0390] The following components were mixed to give the following contents to prepare a pretreatment liquid.

[0391] -Composition of pretreatment solution-

[0392] · Coagulant listed in Table 1: Amount listed in Table 1 (mass %)

[0393] Resins listed in Table 1...Amounts (mass %) listed in Table 1 (content based on solid content of resin)

[0394] Cross-linking agent listed in Table 1: Amount listed in Table 1 (mass %)

[0395] BYK-024 (BYK Japan KK., defoaming agent) ... 0.01 mass%

[0396] ·Dimethylaminoethanol…0.1% by mass

[0397] Surfynol 104 (manufactured by Nissin Chemical Industry Co., Ltd., surfactant) ... 0.5 mass%

[0398] Water ... the remainder of the pretreatment solution to make 100% by mass

[0399] "%" in each amount in Table 1 means mass %.

[0400] The details of the coagulants listed in Table 1 are as follows.

[0401] Glutaric acid...Made by FUJIFILM Wako Pure Chemical Corporation

[0402] Calcium acetate...Calcium acetate (manufactured by FUJIFILM Wako Pure Chemical Corporation)

[0403] The details of the cross-linking agents described in Table 1 are as follows.

[0404] SV-2: CARBODILITE SV-02 (manufactured by Nisshinbo Chemical Inc., a compound having a carbodiimide group)

[0405] WS-500...EPOCROS WS-500 (manufactured by NIPPON SHOKUBAI CO., LTD., a compound having an oxazoline group)

[0406] PZ-33...CHEMITITE PZ-33 (manufactured by NIPPON SHOKUBAI CO., LTD., a compound having an aziridine group)

[0407] The details of the resins described in Table 1 are as follows.

[0408] The resin emulsion refers to a dispersion containing a resin, and the resin exists in the form of resin particles in the liquid.

[0409] SF 500M...SUPERFLEX 500M (manufactured by DKS Co. Ltd., a resin emulsion containing a nonionic urethane resin). The nonionic urethane resin has a glass transition temperature (Tg) of -39°C and an elongation at break of 1100%.

[0410] PUE-1370...PUE-1370 (manufactured by Murayama Chemical Laboratory Co., Ltd., a resin emulsion containing a nonionic urethane resin). The nonionic urethane resin has a glass transition temperature (Tg) of -59°C and an elongation at break of 1200%.

[0411] UA-200: PERMARINE UA-200 (manufactured by SANYO CHEMICAL INDUSTRIES, LTD., a resin emulsion containing anionic urethane resin).

[0412] SF 620: SUPERFLEX 620 (manufactured by DKS Co. Ltd., a resin emulsion containing a cationic urethane resin).

[0413] A615-GE: PESRESIN A615-GE (manufactured by TAKAMATSU OIL & FAT CO., LTD., a resin emulsion containing anionic polyester).

[0414] <Preparation of White Ink>

[0415] First, a pigment dispersion resin W was synthesized to prepare a white ink as an inkjet ink.

[0416] -Synthesis of Pigment Dispersing Resin W-

[0417] 100 g of dipropylene glycol was added to a three-necked flask equipped with a stirrer and a cooling tube, and the mixture was heated to 85° C. under a nitrogen atmosphere.

[0418] A solution 1 was prepared by mixing 14.0 g of octadecyl methacrylate, 35.3 g of benzyl methacrylate, 20.0 g of hydroxyethyl methacrylate, 30.7 g of methacrylic acid, and 0.55 g of 2-mercaptopropionic acid; and a solution 2 was prepared by dissolving 1.0 g of t-butyl peroxy-2-ethylhexanoate (product name "PERBUTYL O", manufactured by NOF CORPORATION) in 20 g of dipropylene glycol.

[0419] Solution 1 was added dropwise to the three-necked flask over 4 hours, and solution 2 was added dropwise over 5 hours.

[0420] After the addition was completed, the mixture was allowed to react for 2 hours, and then the temperature was raised to 95°C and stirred for 3 hours to allow all unreacted monomers to react. The disappearance of the monomers was determined by nuclear magnetic resonance ( 1 The results were confirmed by H-NMR method.

[0421] The obtained reaction solution was heated to 70° C., 12.0 g of dimethylethanolamine was added as an amine compound, and then propylene glycol was added and stirred to obtain a 30% by mass solution of the pigment dispersion resin W.

[0422] pass 1 H-NMR confirmed the structural units of the obtained pigment dispersion resin W. Furthermore, the weight average molecular weight (Mw) determined by GPC was 28,000.

[0423] The mass ratio of each structural unit in the pigment dispersion resin W is octadecyl methacrylate-derived structural unit / benzyl methacrylate-derived structural unit / hydroxyethyl methacrylate-derived structural unit / methacrylic acid-derived structural unit = 14 / 35.3 / 20 / 30.7. However, the above mass ratio does not include dimethylaminoethanol.

[0424] The acid value of the pigment dispersion resin W is 200 mgKOH / g.

[0425] The pigment dispersion resin W is a resin having a carboxyl group.

[0426] -Preparation of Pigment Dispersion W-

[0427] To a zirconia container were added 45 parts by mass of titanium dioxide particles (average primary particle size: 210 nm, product name "PF-690," manufactured by Ishihara Sangyo Kaisha, Ltd.) as a white pigment, 15 parts by mass of a 30% solution of pigment dispersion resin W, and 40 parts by mass of ultrapure water. Furthermore, 40 parts by mass of 0.5 mm zirconia beads (Traceram beads, manufactured by Toray Industries, Inc.) were added and gently mixed with a spatula. The resulting mixture, including the zirconia container, was placed in a Ready Mill (Model LSG-4U-08, manufactured by Aimex Co., Ltd.) and dispersed at 1000 rpm (revolutions per minute) for 5 hours. After dispersion, the beads were removed by filtration through filter cloth, resulting in a pigment dispersion W with a white pigment concentration of 45% by mass.

[0428] -Preparation of white ink-

[0429] Using the prepared pigment dispersion W, the following components were mixed in the following contents to prepare a white ink.

[0430] - Composition of white ink -

[0431] White pigment…15% by mass

[0432] Pigment dispersion resin W (resin having a carboxyl group) ... 1.5 mass%

[0433] 1,2-Propanediol (also known as propylene glycol; PG) ... 20% by mass

[0434] Propylene glycol monomethyl ether...5% by mass

[0435] Surfactant (product name "OLFINE E1010", manufactured by Nissin Chemical Industry Co., Ltd.) ... 0.5% by mass

[0436] Surfactant (product name "BYK-347", manufactured by BYK) ... 0.5% by mass

[0437] Colloidal silicon dioxide (product name "SNOWTEX XS") ... 0.05% by mass in terms of solid content

[0438] Water-soluble resin (polypyrrolidone acetate) (product name "PVP K-15", manufactured by ASHLAND) ... 0.1% by mass

[0439] PERMARIN UA-200 (manufactured by SANYO CHEMICAL INDUSTRIES, LTD., a resin emulsion containing resin particles of a urethane resin having a carboxyl group) ... 4.5% by mass based on the amount of the resin

[0440] Water: The remainder to make the total weight of the white ink 100% by mass

[0441] In Table 1, the amount of the resin having a carboxyl group in the ink refers to the total amount (mass % relative to the total amount of the ink) of the pigment dispersion resin W and the urethane resin having a carboxyl group in PERMARIN UA-200.

[0442] <Image Record>

[0443] Image recording was performed using a pre-treatment liquid and white ink.

[0444] An inkjet recording apparatus was prepared, which included a conveying system for continuously conveying a long substrate, a wire bar coater for applying a pretreatment liquid to the substrate, and an inkjet head for applying white ink.

[0445] Furthermore, a polyethylene terephthalate (PET) substrate ("FE2001" manufactured by FUTAMURA CHEMICAL CO., LTD. (thickness 12 μm, width 780 mm, length 4000 m); hereinafter referred to as "impermeable substrate A") was prepared as an impermeable substrate.

[0446] The pretreatment solution was applied to a coating machine at a concentration of about 2.0 g / m 2 The film was coated onto the non-permeable substrate A in a manner of 0.05 % and then dried at 50° C. for 2 seconds.

[0447] Using an inkjet recording apparatus, while the impermeable substrate A was continuously conveyed at 50 m / min, white ink was ejected from the inkjet head to impart a solid image onto the surface of the impermeable substrate A coated with the pretreatment liquid. The imparted white ink was dried with warm air at 80°C for 30 seconds to form a solid image, thereby obtaining an image record.

[0448] -Ink application conditions-

[0449] Inkjet head: 1200dpi / 30inch wide piezoelectric full-line inkjet head

[0450] Ink ejection volume from inkjet head: 3.0 pL (picoliter)

[0451] Drive frequency: 41kHz (substrate conveying speed: 50m / min)

[0452] [evaluate]

[0453] In each of the Examples and Comparative Examples, the storage stability of the pretreatment liquid and the boiling resistance of the laminate using the image recorded material were evaluated.

[0454] The evaluation method is as follows.

[0455] The evaluation results are shown in Table 1.

[0456] (Storage stability of pretreatment solution)

[0457] The viscosity of the pretreatment liquid after preparation and standing at 25°C for 1 hour (hereinafter referred to as "viscosity before storage") and the viscosity of the pretreatment liquid after preparation and storage at 60°C for 14 days in a sealed state (hereinafter referred to as "viscosity after storage") were measured.

[0458] The viscosity before storage and the viscosity after storage were measured using VISCOMETER TV-22 (manufactured by TOKI SANGYO CO., LTD.) at 25° C. and 100 rpm (revolutions per minute).

[0459] Here, the sealed state means a state in which the contents are sealed in a container and the mass loss of the contents when the contents are stored at 50° C. for 14 days is less than 1% by mass.

[0460] The value obtained by subtracting the viscosity before storage from the viscosity after storage was calculated as the viscosity increase.

[0461] The smaller the viscosity increase, the better the storage stability.

[0462] The evaluation criteria are as follows.

[0463] -Evaluation criteria for storage stability of pretreatment solution-

[0464] 5: Viscosity increase is less than 0.3 mPa·s.

[0465] 4: The viscosity increase is 0.3 mPa·s or more and less than 0.5 mPa·s.

[0466] 3: The viscosity increase is 0.5 mPa·s or more and less than 1.0 mPa·s.

[0467] 2: The viscosity increase is 1.0 mPa·s or more and less than 2.0 mPa·s.

[0468] 1: The viscosity increase is 2.0 mPa·s or more.

[0469] (Boiling resistance of laminate)

[0470] A dry laminator (product name "FL2", manufactured by Fuji Kikai Kogyo Co., Ltd.) was used to apply a dry lamination adhesive (main agent TM-320 (isocyanate) / curing agent CAT-13B (alcohol compound); manufactured by Toyo-Morton, Ltd.) onto the solid image of the image recorded material. A linear low-density polyethylene film (product name "LL-XMTN", manufactured by Futamura Chemical Co., Ltd., thickness 40 μm) was then laminated thereon as a laminating substrate. In this state, the laminating substrate and the image recorded material were bonded together to obtain a laminate.

[0471] The obtained laminate was aged at 40° C. for 48 hours.

[0472] Two sample pieces, 200 mm long and 200 mm wide, were cut from the aged laminate. The cut sample pieces were overlapped and heat-sealed on three sides to form a bag. The bag was filled with pure water and then sealed by heat sealing.

[0473] The sealed bag was placed in a retort food autoclave (small sterilizer) (product name "SR-240", manufactured by TOMY SEIKO CO., LTD.) and boiled at 95°C for 40 minutes.

[0474] After the boiling treatment, the bags were removed and their condition was visually observed. Specifically, the boiling resistance was evaluated based on the presence or absence of bag deformation and laminate warping.

[0475] The evaluation criteria are as follows.

[0476] Furthermore, laminate warping refers to a state in which warping occurs due to peeling of an image or a laminating substrate.

[0477] -Evaluation criteria for boiling resistance of laminated bodies-

[0478] 5: No deformation or laminate warping was observed.

[0479] 4: There is no laminate warping, but deformation is observed.

[0480] 3: One laminate warp was confirmed.

[0481] 2: Multiple laminate warping was observed.

[0482] 1: Laminate warping was observed over the entire surface of the sample sheet.

[0483]

[0484] As shown in Table 1, the examples using a pretreatment liquid containing water, a coagulant, a nonionic urethane resin, and a cross-linking agent showed excellent boiling resistance in the laminated products (i.e., a laminated product obtained by laminating a laminating substrate onto the image in the image recorded product by sequentially applying the pretreatment liquid and inkjet ink to a non-permeable substrate to record an image).

[0485] With respect to each embodiment,

[0486] Comparative Example 1: The pretreatment solution does not contain a crosslinking agent.

[0487] Comparative Example 2: The pretreatment liquid contains an anionic urethane resin instead of the nonionic urethane resin.

[0488] Comparative Example 3: The pretreatment liquid contains a cationic urethane resin instead of a nonionic urethane resin.

[0489] Comparative Example 4 in which the pretreatment liquid contained a polyester resin instead of the nonionic urethane resin and Comparative Example 5 in which the pretreatment liquid did not contain a resin

[0490] The boiling resistance of the laminated body decreased.

[0491] The results of Examples 7, 8, 20, 21, 24, and 25 show that when the crosslinking agent in the pretreatment liquid contains a compound having at least one of a carbodiimide group and an oxazoline group (Examples 7, 8, 20, and 21), the boiling resistance of the laminate is further improved.

[0492] The results of Examples 8 and 9 show that when the crosslinking agent content is 2.0% to 50% by mass relative to the total amount of the nonionic urethane resin (Example 8), the boiling resistance of the laminate is further improved, and the storage stability of the pretreatment solution is further improved. It is believed that the reason why the boiling resistance of the laminate is further improved when the crosslinking agent content is 50% or less by mass relative to the total amount of the nonionic urethane resin is that the flexibility of the image (i.e., the ability to conform to non-permeable substrates) is further improved.

[0493] The results of Examples 8 and 9 show that when the crosslinking agent content is 0.10% to 5.00% by mass relative to the total amount of the pretreatment liquid (Example 8), the boiling resistance of the laminate is further improved, and the storage stability of the pretreatment liquid is further improved.

[0494] From the results of Examples 1 and 2, it can be seen that the ratio of the cross-linking agent in the pre-treatment solution to the carboxyl group-containing resin in the ink (i.e., the amount of the cross-linking agent in the pre-treatment solution applied to the non-permeable substrate (g / m 2) relative to the amount of the resin having a carboxyl group in the ink applied to the non-permeable substrate (g / m 2 When the ratio (mass %) of ) is 1.0 mass % or more (Example 2), the boiling resistance of the laminate is further improved.

[0495] The results of Examples 5 and 6 show that when the addition ratio [crosslinking agent in the pretreatment liquid / resin having a carboxyl group in the ink] is 30 mass % or less (Example 5), the boiling resistance of the laminate is further improved.

[0496] [Example 101] (Evaluation of multi-color images)

[0497] <Preparation of Colored Ink>

[0498] Colored inks (specifically, cyan ink, magenta ink, yellow ink, and black ink) having the compositions shown in Table 2 were prepared.

[0499] [Table 2]

[0500] Cyan ink Magenta ink Yellow ink Black ink APD4000C (solid content) 3 APD4000M (solid content) 4 APD1OOOR (solid content) 2 APD4000Y (solid content) 4 APD4000K (solid content) 7 PG 25 25 25 25 PGmME 3 3 3 3 PGmPE 1 1 1 1 OLFINE E1010 1 1 1 1 BYK-347 1 1 1 1 PVP K-15 0.1 0.1 0.1 0.1 SNOWTEX XS 0.05 0.05 0.05 0.05 PERMARIN UA-200 6 3 5 3 water margin margin margin margin

[0501] In Table 2, the numerical value of each component represents the content (mass %) of the corresponding component in the ink, and the "remainder" as the amount of water represents the remainder for making the total 100 mass %.

[0502] In Table 2, the details of the components including PG (1,2-propylene glycol) are the same as those of the above-mentioned white ink.

[0503] APD4000C and other items in Table 2 are pigment dispersions, and their details are as follows.

[0504] In Table 2, the solid content (the total amount of the pigment and the pigment dispersant) is shown as the amount of the pigment dispersion.

[0505] ·APD4000C...Projet Cyan APD4000(FUJIFILM Imaging

[0506] Colorants, Inc., cyan pigment dispersion, pigment concentration: 20% by mass)

[0507] APD4000M...Projet Magenta APD4000 (manufactured by FUJIFILM Imaging Colorants, Inc., magenta pigment dispersion, pigment concentration: 20% by mass)

[0508] APD1000R...Projet Red APD1000 (manufactured by FUJIFILM Imaging Colorants, Inc., red pigment dispersion, pigment concentration: 16% by mass)

[0509] APD4000Y...Projet Yellow APD4000 (manufactured by FUJIFILM Imaging Colorants, Inc., yellow pigment dispersion, pigment concentration: 20% by mass)

[0510] APD4000K...Projet Black APD4000 (manufactured by FUJIFILM Imaging Colorants, Inc., black pigment dispersion, pigment concentration: 15% by mass)

[0511] <Image Record>

[0512] Image recording was performed using the following.

[0513] The pretreatment liquid of any one of Examples 1 to 27 and Comparative Examples 1 to 5;

[0514] The white ink of Example 1; and

[0515] The colored inks shown in Table 2 above (specifically, cyan ink, magenta ink, yellow ink, and black ink).

[0516] Specifically, the following image recordings A to D were respectively performed to obtain solid images.

[0517] In the following image recordings A to D, the pre-treatment liquid application conditions, the drying conditions after the pre-treatment liquid application, the ink application conditions, and the drying conditions after the ink application were the same as those in the image recording in Example 1.

[0518] Image Recording A ... Image recording is performed by applying a pre-treatment liquid, drying, applying a cyan ink, applying a white ink, and drying in this order.

[0519] Image Recording B ... Image recording is performed by applying a pre-treatment liquid, drying, applying a cyan ink, applying a magenta ink, applying a yellow ink, applying a black ink, applying a white ink, and drying in this order.

[0520] Image Recording C ... Image recording was performed by applying a pre-treatment liquid, drying, applying a cyan ink, drying, applying a white ink, and drying in this order.

[0521] Image Recording D Image recording is performed by applying a pre-treatment liquid, drying, applying a cyan ink, applying a magenta ink, applying a yellow ink, applying a black ink, drying, applying a white ink, and drying in this order.

[0522] Using each image recorded article obtained by image recordings A to D, a laminate was prepared and the boiling resistance of the laminate was evaluated in the same manner as in Example 1.

[0523] As a result, it was confirmed that when the pretreatment liquids in Examples 1 to 27 were used, the laminated body had excellent boiling resistance, similar to Examples 1 to 27 (i.e., single-color image recording using white ink), regardless of which of the image recording methods A to D was performed.

[0524] The entire contents of Japanese Patent Application No. 2023-022852 filed on February 16, 2023 are incorporated herein by reference.

[0525] All documents, patent applications, and technical standards described in this specification are incorporated herein by reference to the same extent as if each individual document, patent application, or technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. A pretreatment liquid for inkjet ink, comprising water, a coagulant, a nonionic urethane resin, and a crosslinking agent.

2. The pre-treatment liquid for inkjet ink according to claim 1, wherein The cross-linking agent contains a compound having at least one of a carbodiimide group and an oxazoline group.

3. The pre-treatment liquid for inkjet ink according to claim 1, wherein The content of the cross-linking agent is 2.0% by mass to 50% by mass based on the total amount of the nonionic urethane resin.

4. The pre-treatment liquid for inkjet ink according to claim 1, wherein The content of the cross-linking agent is 0.10% by mass to 5.00% by mass relative to the total amount of the inkjet ink pre-treatment liquid.

5. An ink set comprising: The pretreatment liquid for inkjet ink according to any one of claims 1 to 4; and Inkjet ink contains water, pigment and resin with carboxyl group.

6. The ink set according to claim 5, wherein: The resin having a carboxyl group contained in the inkjet ink includes a urethane resin having a carboxyl group.

7. The ink set according to claim 5, wherein: The inkjet ink is a white ink containing a white pigment.

8. An image recording method comprising the following steps: applying the inkjet ink pretreatment liquid according to any one of claims 1 to 4 to a non-permeable substrate; and An inkjet ink containing water, a pigment, and a resin having a carboxyl group is applied by an inkjet method to the area of ​​the non-permeable substrate to which the inkjet ink pre-treatment liquid has been applied.

9. The image recording method according to claim 8, wherein: The resin having a carboxyl group contained in the inkjet ink includes a urethane resin having a carboxyl group.

10. The image recording method according to claim 8, wherein: The inkjet ink is a white ink containing a white pigment.

11. The image recording method according to claim 8, wherein: The amount of the crosslinking agent in the inkjet ink pre-treatment liquid applied to the non-permeable substrate is 1.0% to 30% by mass relative to the amount of the carboxyl group-containing resin in the inkjet ink applied to the non-permeable substrate.

12. A method for manufacturing a laminate, comprising the following steps: An image recorded article comprising the impermeable substrate and an image disposed on the impermeable substrate is obtained by the image recording method according to claim 8; and A laminating substrate is laminated on the side of the image recorded material on which the image is arranged to obtain a laminate.

13. An image recorded material comprising an impermeable substrate and an image disposed on the impermeable substrate. The image contains: a pretreatment layer disposed on the non-permeable substrate and containing a coagulant, a nonionic urethane resin, and a cross-linking agent; and The ink layer is disposed on the pretreatment layer and contains a pigment and a resin having a carboxyl group.

14. A laminate comprising: The image record according to claim 13; and A laminating substrate is laminated on the image of the image recorded material.

Images