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

Abstract

Provide are: a pretreatment liquid for inkjet ink, said pretreatment liquid containing water, a flocculant, a non-ionic urethane resin, and a crosslinking agent; and applications thereof.

Description

Pretreatment liquid for inkjet ink, ink set, image recording method, method for manufacturing laminated body, image recorded material, and laminated body

[0001] The present disclosure relates to a pretreatment liquid for inkjet ink, an ink set, an image recording method, a method for manufacturing a laminated body, an image-recorded product, and a laminated body.

[0002] In recent years, various studies have been conducted on pretreatment liquids for inkjet recording on non-absorbent substrates. For example, Patent Document 1 discloses a pretreatment liquid for inkjet recording that is excellent in image fixation, storage stability, and laminate strength on non-absorbent substrates and enables high-quality printing, the pretreatment liquid containing water-insoluble resin fine particles, a flocculant, a crosslinking agent, and water, and the water-insoluble resin fine particles containing composite resin particles in which a polyolefin resin is contained in a polyurethane resin.

[0003] Patent Document 1: JP 2019-177510 A

[0004] Incidentally, there are cases in which a laminated body is produced by applying an inkjet ink pretreatment liquid and an inkjet ink in this order to an impermeable substrate to record an image, and then laminating a laminating substrate onto the image in the obtained image recorded body. This laminated body may be required to have boil resistance (i.e., resistance to boiling treatment).

[0005]

[0010] An object of one embodiment of the present disclosure is to provide a pretreatment liquid for inkjet ink that can improve the boil resistance of a laminated body produced by applying an inkjet ink pretreatment liquid and an inkjet ink in this order to a non-permeable substrate to record an image, and then laminating a laminating substrate onto the image in the obtained image recorded body. Another object of another embodiment of the present disclosure is to provide an ink set including the pretreatment liquid for inkjet ink, as well as an image recording method, a method for producing a laminated body, an image recorded body, and a laminated body that use the pretreatment liquid.

[0006] The present disclosure includes the following aspects. <1> A pretreatment liquid for inkjet ink, comprising water, a flocculant, a nonionic urethane resin, and a crosslinking agent. <2> The pretreatment liquid for inkjet ink according to <1>, wherein the crosslinking agent comprises a compound having at least one of a carbodiimide group and an oxazoline group. <3> The pretreatment liquid for inkjet ink according to <1> or <2>, wherein the content of the crosslinking agent relative to the total amount of the nonionic urethane resin is 2.0% by mass to 50% by mass. <4> The pretreatment liquid for inkjet ink according to any one of <1> to <3>, wherein the content of the crosslinking agent relative to the total amount of the inkjet ink pretreatment liquid is 0.10% by mass to 5.00% by mass. <5> An inkset comprising the pretreatment liquid for inkjet ink according to any one of <1> to <4>, and an inkjet ink comprising water, a pigment, and a resin having a carboxy group. <6> The inkset according to <5>, wherein the resin having a carboxy group contained in the inkjet ink comprises a urethane resin having a carboxy group. <7> The ink set according to <5> or <6>, wherein the inkjet ink is a white ink containing a white pigment. <8> An image recording method comprising: applying a pretreatment liquid for inkjet ink according to any one of <1> to <4> onto a non-permeable substrate; and applying, by an inkjet system, an inkjet ink containing water, a pigment, and a resin having a carboxy group onto the area of ​​the non-permeable substrate to which the pretreatment liquid for inkjet ink has been applied. <9> The image recording method according to <8>, wherein the resin having a carboxy group contained in the inkjet ink includes a urethane resin having a carboxy group. <10> The image recording method according to <8> or <9>, wherein the inkjet ink is a white ink containing a white pigment. <11> The image recording method according to any one of <8> to <10>, wherein the amount of the crosslinking agent applied in the pretreatment liquid for inkjet ink applied onto the non-permeable substrate is 1.0% by mass to 30% by mass with respect to the amount of the resin having a carboxy group in the inkjet ink applied onto the non-permeable substrate.<12> A method for producing a laminated body, comprising: obtaining an image recorded product comprising the non-permeable substrate and an image disposed on the non-permeable substrate by the image recording method according to any one of <8> to <11>; and laminating a substrate for lamination on the side of the image recorded product on which the image is disposed to obtain a laminated body. <13> An image recorded product comprising: a non-permeable substrate and an image disposed on the non-permeable substrate, wherein the image comprises: a pretreatment layer disposed on the non-permeable substrate and containing a flocculant, a nonionic urethane resin, and a crosslinking agent; and an ink layer disposed on the pretreatment layer and containing a pigment and a resin having a carboxy group. <14> A laminated body comprising the image recorded product according to <13>; and a substrate for lamination laminated on the image of the image recorded product.

[0007] According to one embodiment of the present disclosure, there is provided a pretreatment liquid for inkjet inks that can improve the boil resistance of a laminated body when a laminated body is manufactured by applying the pretreatment liquid for inkjet inks and the inkjet ink in this order to a non-permeable substrate to record an image, and laminating a laminating substrate onto the image in the obtained image recorded body. According to another embodiment of the present disclosure, there are provided an ink set including the pretreatment liquid for inkjet inks, and an image recording method, a method for manufacturing a laminated body, an image recorded body, and a laminated body that use the pretreatment liquid.

[0008] The inkjet ink set for non-permeable substrates, the image recording method, the method for producing a laminate, the image-recorded product, and the laminate according to the present disclosure will be described in detail below.

[0009] In this specification, a numerical range indicated using "to" means a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In the numerical ranges described in stages in this specification, the upper or lower limit value described in a certain numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, in the numerical ranges described in this specification, the upper or lower limit value described in a certain numerical range may be replaced with a value shown in the examples.

[0010] As used herein, the amount of each component in a composition refers to the total amount of the components in the composition unless otherwise specified, when the composition contains multiple substances corresponding to each component. In this specification, a combination of two or more preferred aspects is a more preferred aspect. As used herein, 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 is achieved.

[0011] In this specification, the term "image" refers to a film formed by applying a pretreatment liquid and an ink in this order, and the term "image recording" refers to the formation of an image (i.e., a film). The term "image" in this specification also encompasses a solid image.

[0012] In this specification, the term "(meth)acrylate" encompasses both acrylate and methacrylate, and the term "(meth)acrylic" encompasses both acrylic and methacrylic.

[0013] 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 certain period of time (for example, 10 to 120 minutes).

[0014] [Pretreatment Liquid for Inkjet Ink] The pretreatment liquid for inkjet ink (hereinafter also simply referred to as "pretreatment liquid") of the present disclosure contains water, a flocculant, a nonionic urethane resin, and a crosslinking agent.

[0015] According to the pretreatment liquid of the present disclosure, the pretreatment liquid and an inkjet ink (hereinafter also simply referred to as "ink") are applied in this order onto an impermeable substrate to record an image, thereby obtaining an image recorded product, and a laminating substrate is laminated onto the image in the obtained image recorded product to produce a laminated product, thereby improving the boil resistance of the laminated product.

[0016] The reason why the above-mentioned effect of improving the boil resistance of the laminated body is obtained is thought to be that when a pretreatment liquid and an ink are applied in this order to an impermeable substrate to record an image, the crosslinking agent in the pretreatment liquid crosslinks the components in the ink (e.g., a resin having a carboxy group), and the pretreatment liquid contains a nonionic urethane resin, resulting in a hydrophobic image. In other words, the inclusion of the above-mentioned hydrophobic image in the laminated body is thought to suppress water absorption by the laminated body during the boil treatment (i.e., improve the boil resistance of the laminated body). The above-mentioned boil resistance effect is also thought to be contributed by the excellent flexibility (i.e., ability to follow deformation of the impermeable substrate) of the image in the laminated body. The reason why the image has excellent flexibility (i.e., ability to follow deformation of the impermeable substrate) is thought to be due to the presence of a urethane resin in the pretreatment liquid. As described above, the nonionic urethane resin in the pretreatment liquid improves the hydrophobicity of the image due to its nonionic properties, and also improves the flexibility of the image due to its urethane resin content, which is thought to result in an effect of improving the boil resistance of the laminate.

[0017] Each component that can be contained in the pretreatment liquid will be described below.

[0018] <Water> The pretreatment liquid according to the present disclosure contains water. The water content is preferably 50% by mass or more, and more preferably 60% by mass or more, based on the total amount of the pretreatment liquid. The upper limit of the water content, although it depends on the amounts of other components, is preferably 90% by mass or less, and more preferably 80% by mass or less, based on the total amount of the pretreatment liquid.

[0019] The pretreatment liquid according to the present disclosure contains at least one flocculant. The flocculant in the pretreatment liquid flocculates components in the inkjet ink, contributing to improving image quality when an image is recorded by applying the pretreatment liquid and the inkjet ink in this order to a non-permeable substrate.

[0020] As the flocculant, for example, the flocculants described in paragraphs 0122 to 0130 of WO 2020 / 195360 can be used.

[0021] Organic Acids Examples of organic acids include organic compounds having an acidic group.

[0022] Acidic groups include phosphate groups, phosphonate groups, phosphinate groups, sulfate groups, sulfonate groups, sulfinate groups, and carboxy groups.

[0023] Among these, from the viewpoint of the aggregation speed of the ink, the acidic group is preferably a phosphate group or a carboxy group, and more preferably a carboxy group.

[0024] It is preferable that at least a portion of the acidic groups is dissociated in the pretreatment liquid.

[0025] Examples of organic compounds having a carboxy 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.

[0026] Among these, from the viewpoint of the aggregation speed of the ink, the organic compound having a carboxy group is preferably a divalent or higher carboxylic acid (hereinafter also referred to as a polycarboxylic acid), and more preferably a dicarboxylic acid.

[0027] 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.

[0028] The organic acid preferably has a low pKa (for example, 1.0 to 5.0), which reduces the surface charge of particles such as pigments and resin particles in the ink, which are stabilized by weakly acidic functional groups such as carboxyl groups, by contacting them with an organic acid having an even lower pKa, thereby lowering dispersion stability.

[0029] The organic acid preferably has a low pKa, high solubility in water, and a valence of at least 2. Furthermore, the organic acid more preferably has a high buffering capacity in a pH range lower than the pKa of the functional group (e.g., carboxy group) that stabilizes the dispersion of the particles in the ink.

[0030] -Polyvalent Metal Compound- Examples of polyvalent metal compounds include polyvalent metal salts. Examples of polyvalent metal salts include organic acid polyvalent metal salts and inorganic acid polyvalent metal salts. Preferred organic acid polyvalent metal salts are polyvalent metal salts of the above-mentioned organic acids (e.g., formic acid, acetic acid, benzoic acid, etc.). Preferred inorganic acid polyvalent metal salts are polyvalent metal nitrates, polyvalent metal hydrochlorides, or polyvalent metal thiocyanates.

[0031] Examples of polyvalent metal salts include salts of alkaline earth metals (e.g., magnesium, calcium) of Group 2 of the periodic table, salts of transition metals (e.g., lanthanum) of Group 3 of the periodic table, salts of metals (e.g., aluminum) of Group 13 of the periodic table, and salts of lanthanides (e.g., neodymium). As the polyvalent metal salt, calcium salts, magnesium salts, or aluminum salts are preferred, and calcium salts or magnesium salts are more preferred.

[0032] The polyvalent metal compound is preferably an organic acid polyvalent metal salt, more preferably an organic acid calcium salt or an organic acid magnesium salt.

[0033] It is preferable that the polyvalent metal compound is at least partially dissociated into polyvalent metal ions and counter ions in the pretreatment liquid.

[0034] -Metal Complex- The metal complex may contain, as a metal element, at least one selected from the group consisting of zirconium, aluminum, and titanium.

[0035] The metal complex is, for example, a metal complex containing, as a ligand, at least one selected from the group consisting of acetate, acetylacetonate, methylacetoacetate, ethylacetoacetate, octylene glycolate, butoxyacetylacetonate, lactate, lactate ammonium salt, and triethanolamine.

[0036] The metal complex may be a commercially available product. Various organic ligands, particularly various polydentate ligands capable of forming metal chelate catalysts, are commercially available. Therefore, the metal complex may be a metal complex prepared by combining a commercially available organic ligand with a metal.

[0037] The content of the flocculant in the pretreatment liquid is preferably 0.1% by mass to 40% by mass, more preferably 0.1% by mass to 30% by mass, even more preferably 1% by mass to 20% by mass, and still more preferably 1% by mass to 10% by mass, relative to the total amount of the pretreatment liquid.

[0038] From the viewpoint of further improving the boil resistance of the laminate, the flocculant preferably contains at least one selected from the group consisting of an organic acid and an organic acid polyvalent metal salt as a polyvalent metal compound. In this case, the proportion of the total amount of the organic acid and the organic acid polyvalent metal salt in the total amount of the flocculant 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.

[0039] From the viewpoint of further improving the boil resistance of the laminate, it is more preferable that the flocculant contains an organic acid. In this case, the content of the organic acid in the total amount of the flocculant 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.

[0040] <Nonionic Urethane Resin> The pretreatment liquid of the present disclosure contains at least one nonionic urethane resin. As described above, the nonionic urethane resin contributes to improving the boil resistance of the laminate. In particular, as described above, the nonionic urethane resin improves the hydrophobicity of the image by being nonionic (i.e., not having ionicity), and improves the flexibility of the resulting image (i.e., its ability to conform to deformation of an impermeable substrate) by being a urethane resin. As a result of the improved hydrophobicity and flexibility of the image, the boil resistance of the laminate is improved.

[0041] In the present disclosure, a nonionic urethane resin refers to a urethane resin that is not ionic (i.e., anionic or cationic). In the present disclosure, a urethane resin refers to a polymer containing a urethane bond. The urethane resin is synthesized, for example, by reacting a diol compound with a diisocyanate compound. For details on the diol compound and the diisocyanate compound, reference can be made to the descriptions in paragraphs 0031 to 0036 of JP 2001-247787 A. Among these, the nonionic urethane resin is preferably a polyester-based urethane resin having an ester bond in the main chain, a polycarbonate-based urethane resin having a carbonate bond in the main chain, or a polyether-based urethane resin having an ether bond in the main chain.

[0042] The nonionic urethane resin may be a water-soluble urethane resin that dissolves in water, or may be urethane resin particles that are dispersed in water. Among these, from the viewpoint of increasing the strength of the layer obtained by applying the pretreatment liquid (hereinafter also referred to as the pretreatment layer), the nonionic urethane resin is preferably urethane resin particles.

[0043] When the nonionic urethane resin is in the form of urethane resin particles, the average particle diameter 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 viewpoint of the storage stability of the pretreatment liquid. The average particle diameter is determined by measuring the volume average particle diameter by dynamic light scattering using a particle size distribution analyzer, for example, a product name "Nanotrac UPA-EX150" manufactured by Nikkiso Co., Ltd.

[0044] 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.

[0045] In the present disclosure, the weight average molecular weight (Mw) is measured by gel permeation chromatography (GPC). GPC is performed using an HLC-8220GPC (manufactured by Tosoh Corporation), with three columns connected in series: TSKgeL SuperHZM-H, TSKgeL SuperHZ4000, and TSKgel SuperHZ2000 (all trade names manufactured by Tosoh Corporation), and THF (tetrahydrofuran) as the eluent. The conditions are a sample concentration of 0.45% by mass, a flow rate of 0.35 ml / min, a sample injection amount of 10 μl, and a measurement temperature of 40°C, and the measurement is performed using a differential refractive index detector. In addition, a calibration curve is prepared from eight samples of "Standard Sample TSK Standard, Polystyrene" manufactured by Tosoh Corporation: "F-40", "F-20", "F-4", "F-1", "A-5000", "A-2500", "A-1000", and "n-propylbenzene".

[0046] From the viewpoint of further improving the boil 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.

[0047] In the present disclosure, the glass transition temperature is measured using a differential scanning calorimeter, for example, a product named "DSC-60" manufactured by Shimadzu Corporation.

[0048] From the viewpoint of further improving the boil resistance of the laminate, the nonionic urethane resin preferably has a breaking elongation of 300% to 1300%, more preferably 600% to 1300%. When the breaking elongation of the nonionic urethane resin is 300% to 1300%, the internal stress generated by the boil treatment can be reduced, and the boil resistance of the laminate is further improved.

[0049] In the present disclosure, the breaking elongation is measured by the following method. An aqueous solution or dispersion of a nonionic urethane resin is added to a Teflon (registered trademark) container with a bottom area of ​​50 mm x 100 mm and a height of 30 mm, and the solution is dried at 25 ° C. for 24 hours, and then dried at 80 ° C. for 6 hours to obtain a resin film with a thickness of 500 μm. A 10 mm x 50 mm sample is cut out from the resin film, and a tensile test is performed using a precision universal testing machine (product name "Autograph AG-IS", manufactured by Shimadzu Corporation), and the breaking elongation is measured in accordance with JIS K6251:2017.

[0050] The nonionic urethane resin may be a commercially available product, such as the Superflex series manufactured by Daiichi Kogyo Seiyaku Co., Ltd. or the PUE series manufactured by Murayama Chemical Laboratory.

[0051] 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, based on the total amount of the pretreatment liquid.

[0052] The pretreatment liquid may contain a resin other than the nonionic urethane resin. The proportion of the nonionic urethane resin in the total amount of resin components in the pretreatment liquid (i.e., the nonionic urethane resin and resins other than the nonionic urethane resin) is preferably 50% by mass to 100% by mass, more preferably 80% by mass to 100% by mass, and even more preferably 90% by mass to 100% by mass.

[0053] <Crosslinking Agent> The pretreatment liquid according to the present disclosure contains at least one crosslinking agent. In the present disclosure, a crosslinking agent refers to a compound having at least one crosslinking group. Examples of the crosslinking group in the crosslinking agent include a carbodiimide group, an oxazoline group, an aziridine group (also known as an ethyleneimino 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.

[0054] The crosslinking agent preferably contains a compound having at least one of a carbodiimide group and an oxazoline group, which can further improve the boil resistance of the laminate.

[0055] Specific examples of crosslinking agents that are compounds 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-propene)-carbodiimide, N,N'-dipyrrolidylcarbodiimide, N,N'-diethoxycarbodiimide, bis(trimethylsilyl)carbodiimide, 1-cyclohexyl-3-(2-morpholinoethyl)carbodiimide meso-para-toluenesulfonate, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, calcium cyanamide, etc. Commercially available products can also be used as the compound having a carbodiimide group. Commercially available compounds having a carbodiimide group include, for example, Carbodilite V-02, SV-02, V-02-L2, V-04, V-06, E-01, E-02, E-03A, and SW-12G, all manufactured by Nisshinbo Chemical Inc.

[0056] Examples of crosslinking agents that are compounds 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-pyrrolidyl-2-oxazoline, 2-acetyl-2-oxazoline, 2-(2-propene)-2-oxazoline, 4,5-dimethyl-2-oxazoline, 2,4,4-trimethyl-2-oxazoline, 5-phenyl-2-(2-propynylamino)-2-oxazolin-4-one, 4-ethoxymethylene-2-phenyl-2-oxazolin-5-one, etc. Commercially available products can also be used as the compound having an oxazoline group. Commercially available compounds having an oxazoline group include, for example, Epocross 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 Shokubai Co., Ltd.

[0057] Examples of crosslinking agents that are compounds 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. Commercially available products of compounds having an epoxy group can also be used. Commercially available products of compounds having an epoxy group include, for example, Denacol EX-321, EX-821, EX-830, EX-850, and EX-851 manufactured by Nagase ChemteX Corporation.

[0058] Examples of crosslinking agents that are compounds having an aziridine group (also known as an ethyleneimino group) include Chemitite PZ-33 and DZ-22E manufactured by Nippon Shokubai Co., Ltd.

[0059] The content of the crosslinking agent relative to the total amount of nonionic urethane resin is preferably 1.0% by mass to 80% by mass, more preferably 2.0% by mass to 60% by mass, even more preferably 2.0% by mass to 50% by mass, and even more preferably 2.5% by mass to 50% by mass. When the content of the crosslinking agent relative to the total amount of nonionic urethane resin is 1.0% by mass or more, the boil resistance of the laminate is further improved. This is thought to be because the action of the crosslinking agent is more effectively exerted. When the content of the crosslinking agent relative to the total amount of nonionic urethane resin is 80% by mass or less, the boil resistance of the laminate is also further improved. This is thought to be because the flexibility of the obtained image (i.e., its ability to conform to non-permeable substrates) is further improved. When the content of the crosslinking agent relative to the total amount of nonionic urethane resin is 80% by mass or less, the storage stability of the pretreatment liquid is also further improved.

[0060] The content of the crosslinking agent relative to the total amount of the pretreatment liquid is preferably 0.10% by mass to 10.00% by mass, more preferably 0.10% by mass to 8.00% by mass, even more preferably 0.10% by mass to 5.00% by mass, even more preferably 0.20% by mass to 5.00% by mass, and even more preferably 0.25% by mass to 5.00% by mass. When the content of the crosslinking agent relative to the total amount of the pretreatment liquid is 0.10% by mass or more, the boil resistance of the laminate is further improved. This is thought to be because the function of the crosslinking agent is more effectively exerted. When the content of the crosslinking agent relative to the total amount of the pretreatment liquid is 10.00% by mass or less, the boil resistance of the laminate is also further improved. This is thought to be because the flexibility of the obtained image (i.e., its ability to conform to a non-permeable substrate) is further improved. When the content of the crosslinking agent relative to the total amount of the pretreatment liquid is 10.00% by mass or less, the storage stability of the pretreatment liquid is also further improved.

[0061] <Organic Solvent> The pretreatment liquid of the present disclosure may contain at least one organic solvent.

[0062] The type of organic solvent is not limited, and examples thereof include: monoalcohols having 1 to 4 carbon atoms; diols such as 1,3-propanediol, 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; triols such as glycerin, 1,2,6-hexanetriol, and trimethylolpropane; alkylene glycols such as ethylene glycol and propylene glycol; alkylene glycol monoalkyl ethers such as ethylene glycol monoalkyl ethers and propylene glycol monoalkyl ethers; polyalkylene glycols such as diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, dipropylene glycol, and polyoxyethylene polyoxypropylene glycol; Examples thereof include polyalkylene glycol ethers such as diethylene glycol monoalkyl ether, triethylene glycol monoalkyl ether, tripropylene glycol monoalkyl ether, and polyoxypropylene glyceryl ether; 2-pyrrolidone, and N-methyl-2-pyrrolidone.

[0063] The content of the organic solvent is preferably 1% by mass to 20% by mass, and more preferably 3% by mass to 10% by mass, based on the total amount of the pretreatment liquid.

[0064] <Surfactant> The pretreatment liquid of the present disclosure may contain at least one surfactant.

[0065] The type of surfactant is not particularly limited, and may be any of anionic surfactants, cationic surfactants, betaine surfactants, and nonionic surfactants. Examples of surfactants include acrylic surfactants, fluorine-based surfactants, and silicone-based surfactants.

[0066] The content of the surfactant is preferably 0.1% by mass to 5% by mass, and more preferably 0.2% by mass to 1% by mass, based on the total amount of the pretreatment liquid.

[0067] <Other Components> The pretreatment liquid of the present disclosure may contain other components in addition to those described above, as necessary. Examples of other components that can be contained in the pretreatment liquid include known additives such as solid wetting agents, colloidal silica, inorganic salts, anti-fading agents, emulsion stabilizers, penetration enhancers, UV absorbers, preservatives, antifungal agents, 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 JP 2013-001854 A).

[0068] <Physical Properties> The pH of the pretreatment liquid is preferably 2.0 to 7.0, and 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 Toa DKK Corporation (model number "HM-31").

[0069] From the viewpoint of the coatability of the pretreatment liquid, the viscosity of the pretreatment liquid is preferably 0.5 mPa·s to 10 mPa·s, and more preferably 1 mPa·s 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 type viscometer manufactured by Toki Sangyo Co., Ltd.

[0070] 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 (product name "CBVP-Z" manufactured by Kyowa Interface Science Co., Ltd.) by the plate method.

[0071] [Ink Set] The ink set of the present disclosure is an ink set for inkjet recording on a non-permeable substrate, and includes the pretreatment liquid of the present disclosure described above, and an inkjet ink (hereinafter also simply referred to as "ink") containing water, a pigment, and a resin having a carboxy group.

[0072] The ink set of the present disclosure includes the pretreatment liquid of the present disclosure described above, and therefore exhibits the same effects as the pretreatment liquid of the present disclosure described above.

[0073] <Ink> The ink set of the present disclosure includes inks containing water, a pigment, and a resin having a carboxy group. The ink set of the present disclosure may include only one type of ink, or two or more types of ink.

[0074] (Water) The ink contains water. The water content is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, and particularly preferably 50% by mass or more, relative to the total amount of the ink. The upper limit of the water content relative to the total amount of the ink is determined appropriately depending on the contents of other components, but is, for example, 99% by mass, preferably 95% by mass, and more preferably 90% by mass.

[0075] (Resin Having a Carboxy Group) The ink contains at least one resin having a carboxy group.

[0076] - Urethane Resin Having Carboxy Group - The resin having a carboxy group contained in the ink preferably includes a urethane resin having a carboxy group.

[0077] The urethane resin having a carboxy group that can be contained in the ink is preferably a polyester-based urethane resin having a carboxy group and an ester bond in the main chain, a polycarbonate-based urethane resin having a carboxy group and a carbonate bond in the main chain, or a polyether-based urethane resin having a carboxy group and an ether bond in the main chain.

[0078] The urethane resin having a carboxy group that can be contained in the ink may be a water-soluble urethane resin or a water-insoluble urethane resin (i.e., urethane resin particles). Of these, from the viewpoint of increasing the strength of the layer formed by the ink, the urethane resin is preferably urethane resin particles.

[0079] When the urethane resin having a carboxy group that can 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. 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.

[0080] The weight average molecular weight (Mw) of the urethane resin having a carboxy group that can 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. The weight average molecular weight of the urethane resin having a carboxy group that can be contained in the ink can be measured by the same method as that for the weight average molecular weight of the nonionic urethane resin in the pretreatment liquid.

[0081] The urethane resin having a carboxy group that can be contained in the ink may be a commercially available product, such as the Superflex series manufactured by Daiichi Kogyo Seiyaku Co., Ltd., the Permarin UA series and U-Coat series manufactured by Sanyo Chemical Industries, Ltd., the Takelac series manufactured by Mitsui Chemicals, Inc., and the PUE series manufactured by Murayama Chemical Laboratory.

[0082] The content of the urethane resin having a carboxy group that can be contained in the ink is preferably 1% by mass to 25% by mass, more preferably 2% by mass to 20% by mass, and even more preferably 5% by mass to 20% by mass, relative to the total amount of the ink.

[0083] - Pigment dispersing resin having a carboxy group - The resin having a carboxy group contained in the ink may include a pigment dispersing resin having a carboxy group. Examples of the pigment dispersing resin having a carboxy group include the pigment dispersing resins described below that have a carboxy group.

[0084] (Content of Resin Having a Carboxy Group) The content of the resin having a carboxy group in the ink is preferably 1.0% by mass to 10.0% by mass, more preferably 3.0% by mass to 9.0% by mass, and even more preferably 4.0% by mass to 8.0% by mass, relative to the total mass of the ink. For example, if the resin having a carboxy group in the ink is a urethane resin having a carboxy group and a pigment dispersion resin having a carboxy group, the content of the resin having a carboxy group in the ink referred to here is the total amount of the urethane resin having a carboxy group and the pigment dispersion resin having a carboxy group.

[0085] (Pigment) The ink contains at least one pigment. The pigment contained in the ink may be a white pigment or a colored pigment. The ink may be a white ink containing a white pigment, or a colored ink containing a colored pigment.

[0086] In this disclosure, the term "color pigment" refers to a chromatic pigment or a black pigment. In this disclosure, the term "color ink" refers to a chromatic ink (e.g., cyan ink, magenta ink, yellow ink, etc.) or a black ink.

[0087] From the viewpoint of the concealing properties of the resulting image (i.e., the property of concealing the surface on which the image is to be recorded, such as the surface of a non-permeable substrate), the ink is preferably a white ink containing a white pigment. Here, the concealing properties of the image refer to the property of concealing the surface on which the image is to be recorded (e.g., the surface of a non-permeable substrate, the surface of an image formed as a base, etc.).

[0088] (White Pigment) Examples of white pigments include inorganic pigments such as titanium dioxide, barium sulfate, calcium carbonate, silica, zinc oxide, zinc sulfide, mica, talc, and pearl.

[0089] Among these, the white pigment is preferably titanium dioxide, barium sulfate, calcium carbonate, or zinc oxide, and more preferably titanium dioxide.

[0090] From the viewpoint of hiding power, the average primary particle diameter of the white pigment is preferably 150 nm or more, and more preferably 200 nm or more, and from the viewpoint of ink ejection performance, the average primary particle diameter of the white pigment is preferably 400 nm or less, and more preferably 350 nm or less.

[0091] In the present disclosure, the average primary particle diameter of the white pigment is a value measured using a transmission electron microscope (TEM). Specifically, 50 particles of the white pigment are randomly selected within the field of view observed with the TEM, and the primary particle diameters of the 50 particles are measured and averaged. As the transmission electron microscope, a 1200EX transmission electron microscope manufactured by JEOL Ltd. can be used.

[0092] From the viewpoints of image density and ejection performance, the content of the white pigment is preferably 2% by mass to 25% by mass, more preferably 5% by mass to 25% by mass, and even more preferably 10% by mass to 20% by mass, relative to the total amount of the ink.

[0093] The ink may contain a color pigment in addition to, or instead of, the white pigment. When the ink contains a color pigment, the type and content of the color pigment can be determined by referring to the section on the second ink described below.

[0094] (Pigment Dispersion Resin) The ink may contain at least one pigment dispersing resin. In the present disclosure, the pigment dispersing resin refers to a resin that has the function of dispersing a pigment. The pigment dispersing resin may be a random copolymer or a block copolymer. The pigment dispersing resin may also have a crosslinked structure. The ink may be prepared using a pigment dispersion containing a pigment and a pigment dispersing resin.

[0095] The pigment dispersing resin is preferably a random copolymer. 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 viewpoint of dispersion stability, the content ratio (x:y) of the structural units x derived from the hydrophobic monomer to the structural units y derived from the anionic group-containing monomer is preferably 8:1 to 1:1.

[0096] The random copolymer may contain only one type of structural unit derived from a hydrophobic monomer, or may contain two or more types of structural units derived from an anionic group-containing monomer.

[0097] The hydrophobic monomer preferably contains a monomer having a hydrocarbon group having 4 or more carbon atoms, more preferably contains an ethylenically unsaturated monomer having a hydrocarbon group having 4 or more carbon atoms, and even more preferably contains 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.

[0098] Examples of (meth)acrylates having a chain hydrocarbon group having 4 or more carbon atoms include n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, lauryl (meth)acrylate, and stearyl (meth)acrylate. The number of carbon atoms in the chain hydrocarbon group is more preferably 6 or more, even more preferably 8 or more, and particularly preferably 12 or more. Of these, the ethylenically unsaturated monomer having a chain hydrocarbon group having 4 or more carbon atoms is preferably lauryl (meth)acrylate or stearyl (meth)acrylate.

[0099] Examples of (meth)acrylates having an alicyclic hydrocarbon group having 4 or more carbon atoms include (bicyclo[2.2.1]heptyl-2-(meth)acrylic acid), 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, 2-ethyl-2-adamantyl (meth)acrylate, acrylate, 3-hydroxy-1-adamantyl(meth)acrylate, octahydro-4,7-menthanoinden-5-yl(meth)acrylate, octahydro-4,7-menthanoinden-1-ylmethyl(meth)acrylate, 1-menthyl(meth)acrylate, tricyclodecane(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, (nor)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 these, the ethylenically unsaturated monomer having an alicyclic hydrocarbon group having 4 or more carbon atoms is preferably isobornyl (meth)acrylate or cyclohexyl (meth)acrylate.

[0100] 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. Of these, benzyl (meth)acrylate is preferred as the ethylenically unsaturated monomer having an aromatic hydrocarbon group having 4 or more carbon atoms.

[0101] The hydrophobic monomer may further contain a (meth)acrylate having a hydrocarbon group having 1 to 3 carbon atoms.

[0102] Examples of (meth)acrylates 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.

[0103] In particular, from the viewpoint of improving the dispersion stability of the white pigment, the structural units derived from hydrophobic monomers contained in the pigment dispersing resin preferably include 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.

[0104] Examples of the anionic group in the anionic group-containing monomer include a carboxy group, a salt of a carboxy group, a sulfo group, a salt of a sulfo group, a phosphoric acid group, a salt of a phosphoric acid group, a phosphonic acid group, and a salt of a phosphonic acid group.

[0105] Counter ions in salts 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.

[0106] Among these, the anionic group is preferably a carboxy group or a salt of a carboxy group.

[0107] Examples of carboxy group-containing monomers include (meth)acrylic acid, β-carboxyethyl acrylate, fumaric acid, itaconic acid, maleic acid, and crotonic acid.

[0108] 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.

[0109] The ratio of the content of the white pigment to the content of the pigment dispersing 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, on a mass basis.

[0110] From the viewpoint of dispersion stability, the acid value of the pigment dispersing resin is preferably 100 mgKOH / g or more, more preferably 120 mgKOH / g or more, while from the viewpoint of dispersion stability, the acid value of the pigment dispersing resin is preferably 300 mgKOH / g or less, more preferably 230 mgKOH / g or less.

[0111] When the ink contains a pigment dispersion resin, the content of the pigment dispersion resin relative to the total amount of the ink is preferably 0.1% by mass to 10% by mass, more preferably 0.3% by mass to 5% by mass, and even more preferably 0.5% by mass to 2.5% by mass.

[0112] (Organic Solvent) The ink preferably contains an organic solvent, which improves ejection stability. The organic solvent contained in the color ink may be one type or two or more types.

[0113] Examples of the organic solvent include the same organic solvents as those contained in the pretreatment liquid. From the viewpoint of ejection stability, the organic solvent preferably contains at least one selected from the group consisting of alkylene glycols and alkylene glycol monoalkyl ethers.

[0114] 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, based on the total amount of the ink.

[0115] (Additives) The ink may contain additives such as surfactants, water-soluble resins, co-sensitizers, ultraviolet absorbers, antioxidants, anti-fading agents, conductive salts, and basic compounds, as needed.

[0116] (Physical Properties) From the viewpoint of improving ejection stability, the pH (25°C) of the ink is preferably from 7 to 10, and more preferably from 7.5 to 9.5. The pH of the color ink can be measured in the same manner as the pH of the pretreatment liquid.

[0117] The viscosity of the ink (30°C) is preferably 0.5 mPa·s to 30 mPa·s, more preferably 2 mPa·s to 20 mPa·s, more preferably 2 mPa·s to 15 mPa·s, and even more preferably 3 mPa·s to 10 mPa·s. The viscosity of the color ink can be measured in the same manner as the viscosity of the pretreatment liquid.

[0118] The surface tension of the ink (at 25°C) 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 can be measured in the same manner as for the pretreatment liquid.

[0119] <First ink, second ink> The ink set of the present disclosure may include: a white ink (hereinafter also referred to as the "first ink") that is an inkjet ink containing water, a white pigment, and a resin having a carboxy group, as described above; and a colored ink (hereinafter also referred to as the "second ink") that is an inkjet ink containing water, a colored pigment, and a resin having a carboxy group. In this case, the ink set may include two or more types of white ink, or may include two or more types of colored ink (for example, a combination of cyan ink, magenta ink, yellow ink, and black ink).

[0120] That is, one specific aspect of the ink set of the present disclosure is an aspect including: a pretreatment liquid of the present disclosure; a first ink as a white ink, which is an inkjet ink containing water, a white pigment, and a resin having a carboxy group; and a second ink as a colored ink, which is an inkjet ink containing water, a color pigment, and a resin having a carboxy group.

[0121] Preferred aspects of the second ink are the same as preferred aspects of the first ink (i.e., white ink), except that it contains a color pigment as an essential component. 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.

[0122] (Coloring Pigment) The coloring pigment may be either an organic pigment or an inorganic pigment that is usually commercially available. Examples of the coloring pigment include those described in "Pigment Dictionary" edited by Seijiro Ito (published in 2000), "Industrial Organic Pigments" by W. Herbst and K. Hunger, and JP-A Nos. 2002-12607, 2002-188025, 2003-26978, and 2003-342503.

[0123] The color pigment may be a water-insoluble pigment that can be dispersed in water with the aid of a dispersant, or may be a self-dispersing pigment. A self-dispersing pigment is a pigment that can be dispersed in water without the aid of a dispersant. A self-dispersing pigment is a compound in which at least one hydrophilic group selected from the group consisting of a carbonyl group, a hydroxyl group, a carboxyl group, a sulfo group, a phosphate group, and salts thereof is chemically bonded to the surface of the pigment directly or via another group.

[0124] The type of color pigment is not particularly limited, and examples thereof include cyan pigments, magenta pigments, yellow pigments, and black pigments.

[0125] From the viewpoints of image density and ejection properties of the second ink, the content of the color pigment is preferably 1% by mass to 20% by mass, more preferably 1% by mass to 15% by mass, and even more preferably 1% by mass to 10% by mass, relative to the total amount of the second ink.

[0126] [Image Recording Method] The image recording method of the present disclosure includes: a step of applying a pretreatment liquid of the present disclosure onto a non-permeable substrate (hereinafter also referred to as a "pretreatment liquid applying step"); and a step of applying an ink containing water, a pigment, and a resin having a carboxy group (i.e., an inkjet ink; the same applies hereinafter) onto the region of the non-permeable substrate to which the pretreatment liquid has been applied, by an inkjet method (hereinafter also referred to as an "ink applying step").

[0127] The image recording method of the present disclosure uses the pretreatment liquid of the present disclosure described above, and therefore has the same effects as the pretreatment liquid of the present disclosure described above.

[0128] The ink used in the ink application step is the same as the ink described in the section on the ink set of the present disclosure, and preferred embodiments are also the same. For example, the resin having a carboxy group contained in the ink used in the ink application step preferably contains a urethane resin having a carboxy group. Furthermore, from the viewpoint of the concealing properties of the image, the ink used in the ink application step is preferably a white ink containing a white pigment.

[0129] The amount of crosslinking agent applied to the non-permeable substrate in the pretreatment liquid (g / m ２ ) is the amount of resin having a carboxyl group in the ink applied to the non-permeable substrate (g / m ２ ), the amount of the resin having a carboxy group in the ink applied to the non-permeable substrate is preferably 0.3% by mass to 50.0% by mass, more preferably 1.0% by mass to 30.0% by mass, even more preferably 1.0% by mass to 25.0% by mass, and even more preferably 1.0% by mass to 22.0% by mass. Hereinafter, the amount of the resin having a carboxy group applied to the non-permeable substrate (g / m ２ The amount of crosslinking agent applied to the non-permeable substrate in the pretreatment liquid (g / m ２ The ratio (mass %) of the crosslinking agent in the pretreatment liquid to the resin having a carboxy group in the ink is also referred to as the "application amount ratio [crosslinking agent in the pretreatment liquid / resin having a carboxy group in the ink]." When the application amount ratio [crosslinking agent in the pretreatment liquid / resin having a carboxy group in the ink] is 0.3 mass % or more, the boil resistance of the laminated body is further improved. This is thought to be because the action of the crosslinking agent is more effectively exerted. Even when the application amount ratio [crosslinking agent in the pretreatment liquid / resin having a carboxy group in the ink] is such that the content of the crosslinking agent relative to the total amount of the pretreatment liquid is 50.0 mass % or less, the boil resistance of the laminated body is further improved. This is thought to be because the flexibility of the resulting image (i.e., its ability to follow a non-permeable substrate) is further improved.

[0130] Each step of the image recording method of the present disclosure will be described below.

[0131] <Pretreatment Liquid Application Step> The pretreatment liquid application step is a step of applying the pretreatment liquid in the ink set of the present disclosure (i.e., the pretreatment liquid of the present disclosure) onto a non-permeable substrate.

[0132] (Impermeable substrate) In the present disclosure, the impermeability of an impermeable substrate refers to a property in which the water absorption rate over 24 hours measured in accordance with ASTM D570-98 (2018) is 2.5% or less. Here, the unit of water absorption rate, "%", is based on mass. The water absorption rate is preferably 1.0% or less, and more preferably 0.5% or less.

[0133] Examples of materials for the impermeable 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.).

[0134] The material of the impermeable substrate is preferably a resin, that is, the impermeable substrate is preferably a resin substrate.

[0135] Among these, from the viewpoint of versatility, the material of the impermeable substrate is preferably polypropylene, polyethylene, polyethylene terephthalate, nylon, acrylic resin, or polyvinyl chloride.

[0136] The shape of the impermeable substrate is preferably a sheet (film) or plate, and examples of such a shape of the impermeable substrate include a glass plate, a metal plate, a resin sheet (resin film), a plastic-laminated paper, a metal-laminated or metal-deposited paper, and a metal-laminated or metal-deposited plastic sheet (plastic film).

[0137] Examples of impermeable resin substrates include resin sheets (resin films), and specific examples include flexible packaging materials for packaging foods and the like, and floor guide panels in mass retailers.

[0138] Examples of impermeable substrates include not only sheet-shaped (film-shaped) or plate-shaped impermeable substrates, but also textiles (woven fabrics) and nonwoven fabrics formed from impermeable fibers.

[0139] 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.

[0140] The non-permeable substrate may be subjected to a hydrophilization treatment. Examples of hydrophilization 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 carried out using, for example, a Corona Master (product name "PS-10S", manufactured by Shinko Electric Meter Co., Ltd.). The conditions for the corona treatment may be appropriately selected depending on the type of non-permeable substrate, etc.

[0141] The non-permeable substrate may be a transparent non-permeable substrate. Here, "transparent" means that the transmittance of visible light in the wavelength range of 400 nm to 700 nm is 80% or more (preferably 90% or more). When the non-permeable substrate is a transparent non-permeable substrate, an image is easily visible through the non-permeable substrate from the non-image recording surface side of the non-permeable substrate. For example, when the non-permeable substrate is a transparent non-permeable substrate, when an image is recorded on the non-permeable substrate by applying a pretreatment liquid, a second ink as a colored ink, and an ink as a white ink in this order, a colored image (e.g., a pattern image such as letters or figures) against a white image (e.g., a solid image) is easily visible through the non-permeable substrate from the non-image recording surface side of the non-permeable substrate.

[0142] (Application of Pretreatment Liquid) 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.

[0143] Examples of the coating method include known coating methods using a bar coater, extrusion die coater, air doctor coater, blade coater, rod coater, knife coater, squeeze coater, reverse roll coater, and the like.

[0144] 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 / m２ ~4.0g / m ２ is.

[0145] (Heat-Drying of Pretreatment Liquid) The pretreatment liquid application step may include applying the pretreatment liquid onto the non-permeable substrate and heat-drying the pretreatment liquid applied onto the non-permeable substrate. Examples of means for heat-drying the pretreatment liquid include known heating means such as a heater, known air blowing means such as a dryer, and a combination of these.

[0146] Examples of methods for heating and drying the pretreatment liquid include a method of applying heat using a heater or the like from the side opposite to the surface of the non-permeable substrate to which the pretreatment liquid has been applied, a method of applying warm air or hot air to the surface of the non-permeable substrate to which the pretreatment liquid has been applied, a method of applying heat using an infrared heater from the side of the non-permeable substrate to which the pretreatment liquid has been applied or the side opposite to the surface to which the pretreatment liquid has been applied, and a combination of these methods.

[0147] The heating temperature during heating and drying of the pretreatment liquid is preferably 35° C. or higher, and more preferably 40° C. or higher. There is no particular upper limit to the heating temperature, but it is preferably 100° C., more preferably 90° C., and even more preferably 70° C.

[0148] The time for heat drying 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.

[0149] Ink Application Step: In the ink application step, ink is applied by inkjet recording to an area of ​​the non-permeable substrate to which the pretreatment liquid has been applied. In this step, the components in the ink are aggregated on the non-permeable substrate by the action of the aggregating agent in the pretreatment liquid, thereby forming an image.

[0150] (Application of ink) There are no particular limitations on the ink ejection method used in inkjet recording, and any of the well-known methods may be used, such as a charge control method that uses electrostatic attraction to eject ink, a drop-on-demand method (pressure pulse method) that uses the vibration pressure of a piezoelectric element, an acoustic inkjet method that converts an electric signal into an acoustic beam and irradiates the ink with it, thereby ejecting the ink using radiation pressure, and a thermal inkjet (Bubble Jet (registered trademark)) method that heats the ink to form bubbles and uses the resulting pressure.

[0151] As an inkjet recording method, in particular, the method described in JP-A-54-59936 can be effectively used, in which ink subjected to the action of thermal energy undergoes a sudden change in volume, and the ink is ejected from the nozzles by the force caused by this state change. As an inkjet recording method, the method described in paragraphs 0093 to 0105 of JP-A-2003-306623 can also be applied.

[0152] Application of ink to a non-permeable substrate by ink jet recording is carried out by ejecting the ink from the nozzles of an ink jet head.

[0153] Inkjet head methods include the shuttle method, in which a short serial head is scanned across the width of the recording medium to perform recording, and the line method, which uses a line head in which recording elements are arranged to cover the entire area of ​​one side of the recording medium.

[0154] The line method allows for image recording over the entire surface of a recording medium by scanning the recording medium in a direction intersecting the arrangement direction of the recording elements. The line method eliminates the need for a transport system, such as a carriage that scans a short head, as in the shuttle method. Furthermore, compared to the shuttle method, the line method does not require complex scanning control of the carriage movement and the recording medium, and only the recording medium moves. Therefore, the line method achieves faster image recording speeds than the shuttle method.

[0155] The ink is preferably applied using an inkjet head having a resolution of 300 dpi or more (more preferably 600 dpi or more, and even more preferably 800 dpi or more), where dpi stands for dots per inch, and 1 inch is 2.54 cm.

[0156] From the viewpoint of obtaining a high-definition image, the amount of ink droplets ejected is preferably 1 pL (picoliter) to 10 pL, and more preferably 1.5 pL to 6 pL.

[0157] The amount of ink applied to the area on the non-permeable substrate where the pretreatment liquid has been applied is preferably 3.0 g / m ２ ~15.0g / m ２ , more preferably 5.0 g / m ２ ~12.0g / m ２ is.

[0158] (Heat drying) The ink application step may include applying ink by an inkjet method onto the region of the non-permeable substrate to which the pretreatment liquid has been applied, and heating and drying the applied ink.

[0159] The heat drying method is not particularly limited, and examples thereof include infrared (IR) drying, hot air drying, and heat drying using a heating device (e.g., a heater, a hot plate, a heating furnace, etc.). The heat drying method may be a combination of two or more of these. Heat drying can be performed by heating the ink from at least one of the image recording side and the non-image recording side of the non-permeable substrate.

[0160] The heating temperature for drying the ink by heating is preferably 35° C. or higher, more preferably 40° C. or higher, even more preferably 50° C. or higher, and even more preferably 60° C. or higher. There is no particular upper limit to the heating temperature, but 100° C. is preferred, and 90° C. is more preferred.

[0161] The heating time for heating and 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.

[0162] An example of the image recording method of the present disclosure when using inks of two or more colors is an image recording method that uses the first ink (i.e., white ink) and second ink (i.e., colored inks) described above. The image recording method according to this example includes the steps of: applying the pretreatment liquid of the present disclosure onto a non-permeable substrate; and applying the first ink (i.e., white ink) and the second ink (i.e., colored inks) described above, respectively, onto the region of the non-permeable substrate to which the pretreatment liquid has been applied, by inkjet recording.

[0163] The step of applying the pretreatment liquid onto the impermeable substrate is as described above.

[0164] According to the image recording method of this embodiment, a multi-color image can be recorded using a first ink (i.e., white ink) and a second ink (i.e., colored ink). Examples of multi-color images include a colored image (e.g., a pattern image such as letters or figures) against a white background (e.g., a solid image). The order in which the first ink (i.e., white ink) and the second ink (i.e., colored ink) are applied can be any order. For example, when the image is viewed from the image-recording side, the first ink (i.e., white ink) is applied first, followed by the second ink (i.e., colored ink). When the image is viewed from the non-image-recording side through a non-permeable substrate, the second ink (i.e., colored ink) is applied first, followed by the first ink (i.e., white ink). This allows, for example, a multi-color image to be recorded on the non-permeable substrate, in which a pattern image (e.g., letters or figures) recorded with colored inks and a solid white image recorded with white ink so as to cover the pattern image are arranged in this order.

[0165] In the step of applying the first ink and the second ink, the method of applying each of the first ink and the second ink by an inkjet recording method is as described above. Furthermore, the step of applying the first ink and the second ink may include heating and drying the ink after applying at least one of the first ink and the second ink. The preferred conditions for the heating and drying are as described above. For example, an embodiment of this step may include applying the second ink (i.e., colored ink), applying the first ink (i.e., white ink), and drying in this order. In this embodiment, the second ink may or may not be heated and dried between the applications of the second ink.

[0166] [Method for manufacturing a laminated body] The method for manufacturing a laminated body of the present disclosure includes the steps of: obtaining an image recorded matter comprising an impermeable substrate and an image disposed on the impermeable substrate by the image recording method of the present disclosure described above; and laminating a laminating substrate onto the side of the image recorded matter on which the image is disposed, to obtain a laminated body.

[0167] The method for producing a laminate according to the present disclosure includes the image recording method according to the present disclosure, and therefore has the same effects as those of the image recording method according to the present disclosure. Specifically, a laminate having excellent boil resistance can be obtained.

[0168] For the step of obtaining an image recorded material, reference can be made to the image recording method of the present disclosure. The step of obtaining a laminated body 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 laminated body. Lamination can be performed by, for example, a method of overlapping and attaching the laminating substrate to the side on which the image is arranged of the image recorded material via another layer (e.g., an adhesive layer), or a method of overlapping and attaching the laminating substrate to the side on which the image is arranged of the image recorded material through a laminator. In the latter case, a commercially available laminator can be used.

[0169] The lamination temperature when laminating is not particularly limited. For example, when the image-recorded material and the substrate for lamination are attached via another layer (for example, an adhesive layer), the temperature may be in the range of 20°C or higher. Furthermore, when a laminator is used, the temperature of the laminating rolls may be in the range of 20°C to 80°C. The pressure between the pair of laminating rolls may be appropriately selected as needed.

[0170] The substrate for lamination is preferably a resin substrate, and is not particularly limited, but examples thereof include substrates made of thermoplastic resins.

[0171] The resin substrate may be, for example, a substrate formed by molding a thermoplastic resin into a sheet shape, and preferably contains polypropylene, polyethylene terephthalate, nylon, polyethylene, or polyimide.

[0172] The shape of the resin substrate is not particularly limited, but a sheet-like resin substrate is preferred. The thickness of the resin substrate is preferably 10 μm to 200 μm, more preferably 10 μm to 100 μm.

[0173] In the step of obtaining a laminate, the lamination substrate may be laminated directly onto the image-bearing side of the image-recorded product, or may be laminated via another layer (for example, an adhesive layer).

[0174] When the substrate for lamination is directly laminated onto the side of the image-recorded product on which the image is disposed, the lamination can be carried out by a known method such as thermocompression bonding or heat fusion bonding.

[0175] Furthermore, when laminating a substrate for lamination via an adhesive layer onto the side of an image recorded material on which an image is disposed, the lamination can be carried out, for example, by applying an adhesive to the side of the image recorded material on which the image is disposed, then placing the substrate for lamination on the side, and then bonding the image recorded material and the substrate for lamination together.

[0176] Furthermore, lamination via an adhesive layer on the image-bearing side of the image-recorded product can also be carried out by a method such as extrusion lamination (i.e., sandwich lamination).

[0177] The adhesive layer preferably contains an isocyanate. When the adhesive layer contains an isocyanate, the adhesion between the adhesive layer and the image is further improved, and therefore the boiling resistance can be further improved.

[0178] [Image Recorded Material] The image recorded material of the present disclosure comprises an impermeable substrate and an image disposed on the impermeable substrate, wherein the image comprises: a pretreatment layer disposed on the impermeable substrate and containing a flocculant, a nonionic urethane resin, and a crosslinking agent; and an ink layer disposed on the pretreatment layer and containing a pigment and a resin having a carboxy group.

[0179] The image recorded matter of the present disclosure can be produced by the image recording method of the present disclosure, and therefore a laminated article with excellent boil resistance can be produced.

[0180] For 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 referred to as appropriate.

[0181] [Laminated Article] The laminated article of the present disclosure includes the image recorded article of the present disclosure described above, and a laminating substrate laminated onto the image of the image recorded article.

[0182] The laminated body of the present disclosure can be produced by the method for producing a laminated body of the present disclosure. Therefore, the laminated body has excellent boil resistance. Preferred embodiments of the substrate for lamination are as described above.

[0183] Hereinafter, the present disclosure will be described in more detail with reference to examples, but the present disclosure is not limited to the following examples as long as it does not depart from the gist of the disclosure.

[0184] Examples 1 to 27, Comparative Examples 1 to 5 Preparation of Pretreatment Liquid The following components were mixed in the following amounts to prepare a pretreatment liquid.

[0185] - Composition of pretreatment liquid - Flocculant listed in Table 1... amount (mass %) listed in Table 1 - Resin listed in Table 1... amount (mass %) listed in Table 1 (content as resin, which is solid content) - Crosslinker listed in Table 1... amount (mass %) listed in Table 1 - BYK-024 (BYK, antifoaming agent)... 0.01 mass % - Dimethylaminoethanol... 0.1 mass % - Surfynol 104 (Nissin Chemical Industry Co., Ltd., surfactant)... 0.5 mass % - Water... remaining amount to make the total pretreatment liquid 100 mass %

[0186] In Table 1, "%" in each amount means % by mass.

[0187] The details of the flocculants listed in Table 1 are as follows: Glutaric acid...manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Ca acetate...calcium acetate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

[0188] Details of the crosslinking agents listed in Table 1 are as follows: SV-2: Carbodilite SV-02 (manufactured by Nisshinbo Chemical Inc., a compound having a carbodiimide group) WS-500: Epocross WS-500 (manufactured by Nippon Shokubai Co., Ltd., a compound having an oxazoline group) PZ-33: Chemitite PZ-33 (manufactured by Nippon Shokubai Co., Ltd., a compound having an aziridine group)

[0189] Details of the resins listed in Table 1 are as follows. Note that resin emulsion refers to a dispersion containing a resin, and the resin exists as resin particles in the liquid. SF 500M... Superflex 500M (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., a resin emulsion containing a nonionic urethane resin). The glass transition temperature (Tg) of the nonionic urethane resin is -39°C, and the elongation at break is 1100%. PUE-1370... PUE-1370 (manufactured by Murayama Chemical Laboratory, a resin emulsion containing a nonionic urethane resin). The glass transition temperature (Tg) of the nonionic urethane resin is -59°C, and the elongation at break is 1200%. UA-200... Permarin UA-200 (manufactured by Sanyo Chemical Industry Co., Ltd., a resin emulsion containing anionic urethane resin). SF 620: Superflex 620 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., a resin emulsion containing a cationic urethane resin) A615-GE: PES Resin A615-GE (manufactured by Takamatsu Oil & Fat Co., Ltd., a resin emulsion containing anionic polyester).

[0190] <Preparation of White Ink> In preparing the white ink, which is an inkjet ink, first, a pigment dispersion resin W was synthesized.

[0191] -Synthesis of Pigment Dispersion Resin W- 100 g of dipropylene glycol was added to a three-neck flask equipped with a stirrer and a condenser and heated to 85°C under a nitrogen atmosphere. Solution 1 was prepared by mixing 14.0 g of stearyl 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 Solution 2 was prepared by dissolving 1.0 g of t-butylperoxy-2-ethylhexanoate (product name "Perbutyl O", manufactured by NOF Corporation) in 20 g of dipropylene glycol. Solution 1 was added dropwise to the three-neck flask over 4 hours, and Solution 2 was added dropwise over 5 hours. After the dropwise addition, the mixture was allowed to react for an additional 2 hours, and then the temperature was raised to 95°C and heated and stirred for 3 hours to allow all unreacted monomers to react. The disappearance of the monomers was monitored by nuclear magnetic resonance ( １The resulting reaction solution was heated to 70°C, and 12.0 g of dimethylethanolamine was added as an amine compound. Then, propylene glycol was added and the mixture was stirred to obtain a 30% by mass solution of pigment dispersion resin W. The structural unit of the resulting pigment dispersion resin W was １ The molecular weight was confirmed by H-NMR. The weight average molecular weight (Mw) determined by GPC was 28,000. The mass ratio of the structural units in pigment dispersion resin W was stearyl methacrylate-derived structural units / benzyl methacrylate-derived structural units / hydroxyethyl methacrylate-derived structural units / methacrylic acid-derived structural units = 14 / 35.3 / 20 / 30.7. However, the above mass ratio does not include dimethylaminoethanol. The acid value of pigment dispersion resin W was 200 mg KOH / g. Pigment dispersion resin W is a resin having a carboxy group.

[0192] Preparation of Pigment Dispersion W: 45 parts by mass of titanium dioxide particles (average primary particle diameter: 210 nm, product name "PF-690", manufactured by Ishihara Sangyo Kaisha, Ltd.) serving as a white pigment, 15 parts by mass of a 30% by mass solution of pigment dispersion resin W, and 40 parts by mass of ultrapure water were added to a zirconia container. 40 parts by mass of 0.5 mm diameter zirconia beads (Toraceram beads, manufactured by TORAY Corporation) were then added and gently mixed with a spatula. The zirconia container containing the resulting mixture was placed in a ready mill (Model LSG-4U-08, manufactured by Imex Co., Ltd.), and dispersion was carried out for 5 hours at a rotation speed of 1000 rpm (revolutions per minute). After dispersion was complete, the beads were removed by filtration using a filter cloth, yielding a pigment dispersion W having a white pigment concentration of 45% by mass.

[0193] - Preparation of White Ink - Using the prepared pigment dispersion W, the following components were mixed in the following amounts to prepare a white ink.

[0194] - Composition of white ink - White pigment: 15% by mass; Pigment dispersion resin W (resin having a carboxy group): 1.5% by mass; 1,2-propanediol (also known as propylene glycol; PG): 20% by mass; Propylene glycol monomethyl ether: 5% by mass; Surfactant (product name "Olfine E1010", manufactured by Nissin Chemical Industry Co., Ltd.): 0.5% by mass; Surfactant (product name "BYK-347", manufactured by BYK): 0.5% by mass; Colloidal silica (product name "Snowtex XS"): 0.05% by mass as solid content; Water-soluble resin (polyvinylpyrrolidone): (product name "PVP K-15", manufactured by ASHLAND): 0.1% by mass; Permarin UA-200 (manufactured by Sanyo Chemical Industry Co., Ltd.; resin emulsion containing resin particles which are urethane resins having a carboxy group) Resin amount: 4.5% by mass Water: The remaining amount to make the total white ink 100% by mass

[0195] In Table 1, the amount of resin having a carboxy group in the ink means the total amount (mass % relative to the total amount of ink) of pigment dispersion resin W and the urethane resin having a carboxy group in Permarin UA-200.

[0196] <Image Recording> Image recording was performed using the pretreatment liquid and white ink. An inkjet recording apparatus was prepared, which included a conveying system for continuously conveying a long substrate, a wire bar coater for applying the pretreatment liquid to the substrate, and an inkjet head for applying the white ink. Furthermore, a non-permeable polyethylene terephthalate (PET) substrate ("FE2001" manufactured by Futamura Chemical Co., Ltd., 12 μm thick, 780 mm wide, and 4000 m long; hereinafter referred to as "non-permeable substrate A") was prepared as the substrate.

[0197] The above pretreatment liquid was applied to the non-permeable substrate A at a rate of about 2.0 g / m using a wire bar coater. ２The white ink was applied in the form of a solid image from an inkjet head while continuously conveying the non-permeable substrate A at 50 m / min using an inkjet recording device. The applied white ink was dried with hot air at 80°C for 30 seconds to record a solid image, thereby obtaining an image recording.

[0198] - Ink application conditions - Inkjet head: 1200 dpi / 30 inch wide piezo full line head Amount of ink ejected from inkjet head: 3.0 pL (picoliters) Driving frequency: 41 kHz (substrate conveying speed: 50 m / min)

[0199] [Evaluation] For each example and comparative example, the storage stability of the pretreatment liquid and the boil resistance of the laminate using the image recorded material were evaluated. The evaluation methods are as follows. The evaluation results are shown in Table 1.

[0200] (Storage Stability of Pre-Treatment Liquid) The viscosity of the pre-treatment liquid prepared and then allowed to stand at 25°C for 1 hour (hereinafter referred to as "viscosity before storage") and the viscosity of the pre-treatment liquid prepared and then stored in a sealed state at 60°C for 14 days (hereinafter referred to as "viscosity after storage") were measured. Both the viscosity before storage and the viscosity after storage were measured using a VISCOMETER TV-22 (manufactured by TOKI SANGYO CO., LTD.) at 25°C and 100 rpm (revolutions per minute). Here, a sealed state refers to a state in which the contents are sealed in a container and, when stored at 50°C for 14 days, the amount of weight loss of the contents is less than 1% by mass. The viscosity increase was calculated by subtracting the viscosity before storage from the viscosity after storage. The smaller the viscosity increase, the better the storage stability. The evaluation criteria are as follows.

[0201] - Evaluation criteria for storage stability of pre-treatment liquid - 5: The viscosity increase was less than 0.3 mPa s. 4: The viscosity increase was 0.3 mPa s or more and less than 0.5 mPa s. 3: The viscosity increase was 0.5 mPa s or more and less than 1.0 mPa s. 2: The viscosity increase was 1.0 mPa s or more and less than 2.0 mPa s. 1: The viscosity increase was 2.0 mPa s or more.

[0202] (Boiling resistance of laminated body) Using a dry laminating machine (product name "FL2", manufactured by Fuji Machine Industry Co., Ltd.), a dry laminating adhesive (main agent TM-320 (isocyanate) / curing agent CAT-13B (alcohol compound); manufactured by Toyo-Morton Co., Ltd.) was applied onto the solid image of the image recorded material, and a linear low-density polyethylene film (product name "LL-XMTN", manufactured by Futamura Chemical Co., Ltd., thickness 40 μm) was placed thereon as a laminating substrate. In this state, the laminating substrate and the image recorded material were bonded together to obtain a laminated body.

[0203] The resulting laminate was aged at 40°C for 48 hours. Two sample pieces, each 200 mm long and 200 mm wide, were cut out from the aged laminate. The cut-out sample pieces were overlapped and heat-sealed on three sides to obtain a bag. The resulting bag was filled with pure water and then heat-sealed.

[0204] The sealed bag was placed in an autoclave (small sterilizer) for retort foods (product name "SR-240", manufactured by Tommy Seiko Co., Ltd.) and subjected to boiling treatment at 95°C for 40 minutes. After boiling treatment, the bag was removed and the condition of the bag was visually observed. Specifically, boil resistance was evaluated based on the deformation of the bag and the presence or absence of laminate lifting. The evaluation criteria are as follows. Laminate lifting refers to a state in which lifting occurs due to peeling of the image or laminate substrate.

[0205] - Evaluation criteria for boil resistance of laminate - 5: No deformation or laminate lifting was observed. 4: No laminate lifting, but deformation was observed. 3: Laminate lifting was observed in one location. 2: Laminate lifting was observed in multiple locations. 1: Laminate lifting was observed over the entire surface of the sample piece.

[0206]

[0207] As shown in Table 1, each Example using a pretreatment liquid containing water, a flocculant, a nonionic urethane resin, and a crosslinking agent produced a laminate (i.e., a laminate obtained by applying the pretreatment liquid and inkjet ink in this order to an impermeable substrate to record an image, and then laminating a laminating substrate onto the image in the obtained image recorded material) with excellent boil resistance. Compared to each Example, the boil resistance of the laminate was reduced in Comparative Example 1, in which the pretreatment liquid did not contain a crosslinking agent; Comparative Example 2, in which the pretreatment liquid contained an anionic urethane resin instead of the nonionic urethane resin; Comparative Example 3, in which the pretreatment liquid contained a cationic urethane resin instead of the nonionic urethane resin; 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.

[0208] 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 boil resistance of the laminate is further improved.

[0209] The results of Examples 8 and 9 show that when the content of the crosslinking agent relative to the total amount of nonionic urethane resin is 2.0% by mass to 50% by mass (Example 8), the boil resistance of the laminate is further improved and the storage stability of the pretreatment liquid is further improved. The reason why the boil resistance of the laminate is further improved when the content of the crosslinking agent relative to the total amount of nonionic urethane resin is 50% by mass or less is thought to be because the flexibility of the image (i.e., its ability to conform to a non-permeable substrate) is further improved.

[0210] The results of Examples 8 and 9 show that when the content of the crosslinking agent relative to the total amount of the pretreatment liquid is 0.10 mass % to 5.00 mass % (Example 8), the boil resistance of the laminated body is further improved, and the storage stability of the pretreatment liquid is further improved.

[0211] From the results of Examples 1 and 2, the ratio of the amount of application [crosslinking agent in the pretreatment liquid / resin having a carboxy group in the ink] (i.e., the amount of the resin having a carboxy group in the ink applied to the non-permeable substrate (g / m)) ２ The amount of crosslinking agent applied to the non-permeable substrate in the pretreatment liquid (g / m ２ It can be seen that when the ratio (mass %) of the applied amount [crosslinking agent in the pretreatment liquid / resin having a carboxy group in the ink] is 1.0 mass % or more (Example 2), the boil resistance of the laminated article is further improved. From the results of Examples 5 and 6, it can be seen that when the applied amount ratio [crosslinking agent in the pretreatment liquid / resin having a carboxy group in the ink] is 30 mass % or less (Example 5), the boil resistance of the laminated article is further improved.

[0212] Example 101 (Evaluation of Multi-Color Images) <Preparation of Colored Inks> Colored inks (specifically, cyan ink, magenta ink, yellow ink, and black ink) having the compositions shown in Table 2 were prepared.

[0213]

[0214] In Table 2, the numerical value of each component indicates its content (mass %) in the corresponding ink, and the "remaining amount," which is the amount of water, indicates the remaining amount to make the total 100 mass %. In Table 2, the details of the components after PG (1,2-propanediol) are the same as those of the white ink components described above.

[0215] APD4000C and the like in Table 2 are pigment dispersions, and the details are as follows: In Table 2, the amount of pigment dispersion indicates the solid content (total amount of pigment and pigment dispersant). APD4000C ... Projet Cyan APD4000 (manufactured by FUJIFILM Imaging Colorants, cyan pigment dispersion, pigment concentration: 20% by mass) APD4000M ... Projet Magenta APD4000 (manufactured by FUJIFILM Imaging Colorants, magenta pigment dispersion, pigment concentration: 20% by mass) APD1000R ... Projet Red APD1000 (manufactured by FUJIFILM Imaging Colorants, red pigment dispersion, pigment concentration: 16% by mass) APD4000Y ... Projet Yellow APD4000 (manufactured by FUJIFILM Imaging Colorants, yellow pigment dispersion, pigment concentration: 20% by mass) APD4000K ... Projet Black APD4000 (FUJIFILM Imaging Colorants, black pigment dispersion, pigment concentration: 15% by mass

[0216] <Image Recording> Image recording was performed using the pretreatment liquid in any one of Examples 1 to 27 and Comparative Examples 1 to 5, the white ink in Example 1, and the colored inks shown in Table 2 above (specifically, cyan ink, magenta ink, yellow ink, and black ink). Specifically, each of the following image recordings A to D was performed to obtain a solid image. In the following image recordings A to D, the pretreatment liquid application conditions, drying conditions after application of the pretreatment liquid, ink application conditions, and drying conditions after application of the ink were the same as those in the image recording of Example 1.

[0217] Image recording A: Image recording carried out in the order of applying a pretreatment liquid, drying, applying cyan ink, applying white ink, and drying. Image recording B: Image recording carried out in the order of applying a pretreatment liquid, drying, applying cyan ink, applying magenta ink, applying yellow ink, applying black ink, applying white ink, and drying. Image recording C: Image recording carried out in the order of applying a pretreatment liquid, drying, applying cyan ink, drying, applying white ink, and drying. Image recording D: Image recording carried out in the order of applying a pretreatment liquid, drying, applying cyan ink, applying magenta ink, applying yellow ink, applying black ink, drying, applying white ink, and drying.

[0218] Using each image recorded material obtained in image recording A to D, a laminate was produced and the boil resistance of the laminate was evaluated in the same manner as in Example 1. As a result, it was confirmed that when the pretreatment liquid in Examples 1 to 27 was used, the boil resistance of the laminate was excellent, similar to Examples 1 to 27 (i.e., image recording with a single color of white ink), regardless of whether image recording A to D was performed.

[0219] The disclosure of Japanese Patent Application No. 2023-022852, filed on February 16, 2023, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. A pretreatment liquid for inkjet inks, comprising water, a flocculant, a nonionic urethane resin, and a crosslinking agent, the crosslinking agent containing a compound having at least one of a carbodiimide group and an oxazoline group.

2. 2. The inkjet ink pretreatment liquid according to claim 1, wherein the content of the crosslinking agent relative to the total amount of the nonionic urethane resin is 2.0% by mass to 50% by mass.

3. 2. The ink-jet ink pretreatment liquid according to claim 1, wherein the content of the crosslinking agent relative to the total amount of the ink-jet ink pretreatment liquid is 0.10% by mass to 5.00% by mass.

4. A pretreatment liquid for inkjet ink according to any one of claims 1 to 3, an inkjet ink containing water, a pigment, and a resin having a carboxy group; Including, an ink set.

5. The ink set according to claim 4 , wherein the resin having a carboxy group contained in the inkjet ink comprises a urethane resin having a carboxy group.

6. The ink set according to claim 4 , wherein the inkjet ink is a white ink containing a white pigment.

7. applying the inkjet ink pretreatment liquid according to any one of claims 1 to 3 onto an impermeable substrate; applying, by an inkjet method, an inkjet ink containing water, a pigment, and a resin having a carboxy group onto the region of the non-permeable substrate to which the inkjet ink pretreatment liquid has been applied; An image recording method comprising:

8. The image recording method according to claim 7 , wherein the resin having a carboxy group contained in the inkjet ink includes a urethane resin having a carboxy group.

9. The image recording method according to claim 7 , wherein the ink-jet ink is a white ink containing a white pigment.

10. 8. The image recording method according to claim 7, wherein an amount of the crosslinking agent in the inkjet ink pretreatment liquid applied to the non-permeable substrate is 1.0% by mass to 30% by mass with respect to an amount of the resin having a carboxy group in the inkjet ink applied to the non-permeable substrate.

11. a step of obtaining an image recorded matter comprising the impermeable substrate and an image disposed on the impermeable substrate by the image recording method according to claim 7; a step of laminating a substrate for lamination onto the side of the image-recorded product on which the image is arranged to obtain a laminate; A method for producing a laminate comprising the steps of:

12. an impermeable substrate; and an image disposed on the impermeable substrate; The image is a pretreatment layer disposed on the impermeable substrate and containing a flocculant, a nonionic urethane resin, and a crosslinking agent; an ink layer disposed on the pretreatment layer and containing a pigment and a resin having a carboxy group; Including, Image recording.

13. The image recording material according to claim 12; a lamination substrate laminated onto the image of the image recording material; A laminate body comprising:

14. A pretreatment liquid for inkjet printing on non-permeable substrates, comprising water, a flocculant, a nonionic urethane resin, and a crosslinking agent.

15. A method for producing a printing ink, comprising: applying a pretreatment liquid for inkjet ink, the pretreatment liquid containing water, a flocculant, a nonionic urethane resin, and a crosslinking agent, onto an impermeable substrate; applying, by an inkjet method, an inkjet ink containing water, a pigment, and a resin having a carboxy group onto the region of the non-permeable substrate to which the inkjet ink pretreatment liquid has been applied; An image recording method comprising: