Pre-treatment liquid for inkjet ink, ink set, image recording method, method for manufacturing laminate, image recorded matter, and laminate

Abstract

A pretreatment liquid for inkjet ink and use thereof, the pretreatment liquid for inkjet ink containing: a coagulant, which is at least one selected from the group consisting of an organic acid, a polyvalent metal compound, and a metal complex; water; and a urethane resin, the urethane resin including a polyol unit, a polyisocyanate unit, and a polyalkylene glycol monoalkyl ether unit.

Description

Technical Field

[0001] This invention relates to a pretreatment liquid for inkjet ink, an ink assembly, an image recording method, a method for manufacturing a laminate, an image recorder, and a laminate. Background Technology

[0002] In the past, various studies have been conducted on image recording methods using pretreatment solutions and inks.

[0003] For example, in Patent Document 1, as a printing method (i.e., image recording method) capable of forming an image with excellent abrasion resistance, a printing method is described, which includes: a process liquid application step, in which a process liquid is applied to a recording medium; and an ink application step, in which ink is applied to the recording medium, wherein the process liquid contains a nonionic resin having urethane bonds, the glass transition temperature of the nonionic resin being below 15°C, and the ink contains a nonionic resin having urethane bonds and a pigment.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2018-154118 Summary of the Invention

[0005] The technical problem to be solved by the invention

[0006] Sometimes, an image record is obtained by sequentially applying a pretreatment solution for inkjet ink and inkjet ink to a non-permeable substrate to record an image, and then laminating a substrate onto the image of the obtained image record to manufacture a laminate. Sometimes, the laminate is required to have boiling resistance (i.e., resistance to boiling treatment).

[0007] Furthermore, the storage stability of pretreatment solutions for inkjet inks is sometimes required.

[0008] One embodiment of the present invention aims to provide a pretreatment liquid for inkjet printing, which sequentially applies the pretreatment liquid for inkjet ink and inkjet ink to a non-permeable substrate to record an image and obtain an image record. Furthermore, when a laminating substrate is laminated onto the image of the obtained image record to manufacture a laminate, the boiling resistance of the laminate is improved and the storage stability is excellent.

[0009] Another embodiment of the present invention aims to solve the problem of providing an ink assembly comprising the above-described inkjet ink pretreatment liquid and an ink assembly using the above-described inkjet ink pretreatment liquid, an image recording method, a method for manufacturing a laminate, an image recorder, and a laminate.

[0010] means for solving technical problems

[0011] The present invention includes the following methods.

[0012] <1> A pretreatment solution for inkjet ink, comprising: a coagulant selected from at least one of the group consisting of organic acids, polyvalent metal compounds, and metal complexes; water; and a urethane resin.

[0013] Carbamate resins contain polyol units, polyisocyanate units, and polyalkylene glycol monoalkyl ether units.

[0014] <2> According to <1>, the pretreatment solution for inkjet ink, wherein,

[0015] When the number-average molecular weight of the polyalkylene glycol monoalkyl ether used to form the polyalkylene glycol monoalkyl ether unit is set as a and the number-average molecular weight of the urethane resin is set as b, (a / b)×100 is 2.5 to 20.0.

[0016] <3> The pretreatment solution for inkjet inks according to <1> or <2>, wherein,

[0017] The content of polyalkylene glycol monoalkyl ether units is 5% to 20% by mass relative to the total amount of urethane resin.

[0018] <4> The pretreatment solution for inkjet ink according to any one of <1> to <3>, wherein,

[0019] The polyol unit contains a polycarbonate diol unit.

[0020] <5> The pretreatment solution for inkjet ink according to any one of <1> to <4>, wherein,

[0021] The coagulant contains at least one selected from the group consisting of organic acids and organic acid polyvalent metal salts as polyvalent metal compounds.

[0022] <6> The pretreatment solution for inkjet ink according to any one of <1> to <5>, wherein,

[0023] Coagulants contain organic acids.

[0024] <7> An ink group comprising:

[0025] Pretreatment solution for inkjet inks as described in any one of <1> to <6>; and

[0026] The first ink is an inkjet ink containing water and urethane resin.

[0027] <8> According to the ink group described in <7>, wherein,

[0028] The first ink also contains white pigment.

[0029] <9> The ink group according to <8> further includes a second ink, which is an inkjet ink containing water, coloring pigments and urethane resin.

[0030] <10> An image recording method using the ink set described in <7> or <8>, the image recording method comprising:

[0031] The process of applying a pretreatment solution for inkjet ink to a non-permeable substrate; and

[0032] The process of applying a first ink to a non-permeable substrate that has been treated with an inkjet ink pretreatment solution by inkjet recording.

[0033] <11> An image recording method using the ink set described in <9>, the image recording method comprising:

[0034] The process of applying a pretreatment solution for inkjet ink to a non-permeable substrate; and

[0035] The process of applying the first ink and the second ink to a non-permeable substrate on which a pretreatment solution for inkjet ink has been applied by inkjet recording.

[0036] <12> A method for manufacturing a laminate, comprising:

[0037] The process of obtaining an image recording article by the image recording method described in <10> or <11>, wherein the image recording article comprises a non-permeable substrate and an image disposed on the non-permeable substrate; and

[0038] The process of laminating a laminating substrate onto the side of an image recorder containing the image to obtain a laminate.

[0039] <13> An image recording article comprising a non-permeable substrate and an image disposed on the non-permeable substrate, the image including:

[0040] A pretreatment layer, disposed on a non-permeable substrate, and containing a coagulant and a urethane resin, wherein the coagulant is at least one selected from the group consisting of organic acids, polyvalent metal compounds, and metal complexes; and

[0041] The ink layer, disposed on the pretreatment layer, contains pigments and urethane resin.

[0042] The urethane resin in the pretreatment layer comprises polyol units, polyisocyanate units, and polyalkylene glycol monoalkyl ether units.

[0043] <14> A laminate comprising:

[0044] The image recording object described in <13>; and

[0045] A laminating substrate, laminated onto the image of an image recorder.

[0046] Invention Effects

[0047] According to one embodiment of the present invention, a pretreatment liquid for inkjet printing is provided, which is applied sequentially to an inkjet ink pretreatment liquid and inkjet ink on a non-permeable substrate to record an image and obtain an image record. When a laminating substrate is laminated on the image of the obtained image record to manufacture a laminate, the boiling resistance of the laminate can be improved and the storage stability is excellent.

[0048] According to another embodiment of the present invention, an ink assembly comprising the above-described inkjet ink pretreatment liquid and an ink assembly using the above-described inkjet ink pretreatment liquid, an image recording method, a method for manufacturing a laminate, an image recorder, and a laminate are provided. Detailed Implementation

[0049] The following provides a detailed description of the non-permeable substrate inkjet ink set, image recording method, laminate manufacturing method, image recorder, and laminate of the present invention.

[0050] In this specification, the numerical range represented by “~” indicates the range included by taking the values ​​before and after “~” as the minimum and maximum values, respectively.

[0051] Within the numerical ranges described in this specification, the upper or lower limit of a certain numerical range can be replaced with the upper or lower limit of other numerical ranges described in different periods. Furthermore, within the numerical ranges described in this specification, the upper or lower limit of a certain numerical range can also be replaced with the values ​​shown in the embodiments.

[0052] In this specification, if a composition contains multiple substances corresponding to each component, unless otherwise specified, the amount of each component in the composition represents the total amount of the multiple substances present in the composition.

[0053] In this specification, a combination of two or more preferred methods is a more preferred method.

[0054] In this specification, the term "process" includes not only individual processes, but also processes that achieve the desired purpose of the process, even if they cannot be clearly distinguished from other processes.

[0055] In this specification, "image" refers to the entire membrane formed by sequentially applying a pretreatment solution and ink, and "image recording" refers to the formation of an image (i.e., the membrane).

[0056] Furthermore, the concept of "image" in this specification also includes solid images.

[0057] In this specification, "(meth)acrylate" is a concept that includes both acrylates and methacrylates. Furthermore, "(meth)acrylic acid" is a concept that includes both acrylic acid and methacrylic acid.

[0058] In this specification, "boiling treatment" refers to the process of immersing the object (specifically the laminate) in water at 60 to 100°C for a specified time (e.g., 10 to 120 minutes).

[0059] [Pretreatment solution for inkjet inks]

[0060] The inkjet ink pretreatment solution (hereinafter also simply referred to as "pretreatment solution") of the present invention contains:

[0061] The coagulant is at least one selected from the group consisting of organic acids, polyvalent metal compounds, and metal complexes; water; and urethane resin.

[0062] Carbamate resins contain polyol units, polyisocyanate units, and polyalkylene glycol monoalkyl ether units.

[0063] According to the pretreatment liquid of the present invention, when an image is recorded by sequentially applying the pretreatment liquid and inkjet ink (hereinafter, sometimes simply referred to as "ink") to a non-permeable substrate to obtain an image record, and when a laminate is manufactured by laminating a substrate on the image of the obtained image record, the boiling resistance of the laminate can be improved.

[0064] Furthermore, the pretreatment solution of the present invention exhibits excellent storage stability.

[0065] The reason for the improved boiling resistance of the above-mentioned laminate is believed to be that the pretreatment solution contains urethane resin, thereby improving the softness of the layer derived from the pretreatment solution and its adhesion to non-permeable substrates.

[0066] Furthermore, it is believed that the combination of the agglomerator with the polyalkylene glycol monoalkyl ether unit in the urethane resin further contributes to the improved boiling resistance of the above-mentioned laminate.

[0067] In detail, it is believed that through the combined action of the coagulant in the pretreatment solution and the alkylene glycol monoalkyl ether units contained in the urethane resin in the pretreatment solution, the compatibility between the layer derived from the pretreatment solution and the layer derived from the ink on a non-permeable substrate is improved, resulting in improved boil resistance of the laminate. Furthermore, it is believed that improving the flexibility of the urethane resin and its adhesion to the non-permeable substrate also contributes to improving the boil resistance of the laminate.

[0068] Furthermore, coagulants in pretreatment solutions typically reduce the dispersibility of the resin. However, in the pretreatment solution of the present invention, the dispersibility of the urethane resin is well maintained through the action of the alkylene glycol monoalkyl ether units contained in the urethane resin. As a result, the pretreatment solution of the present invention is considered to be a pretreatment solution containing both a coagulant and resin, but exhibits excellent storage stability.

[0069] The following describes the components that may be present in the pretreatment solution.

[0070] <Water>

[0071] The pretreatment solution of this invention contains water.

[0072] The water content relative to the total amount of the pretreatment liquid is preferably 50% by mass or more, and more preferably 60% by mass or more.

[0073] The upper limit of water content also depends on the amount of other components, but it is preferably 90% by mass or less, more preferably 80% by mass or less, relative to the total amount of pretreatment liquid.

[0074] <Flocculant>

[0075] The pretreatment liquid of the present invention contains a coagulant, which is selected from at least one of the group consisting of organic acids, polyvalent metal compounds and metal complexes.

[0076] As mentioned above, coagulants help improve the boiling resistance of laminates.

[0077] As a coagulant, the coagulants described in paragraphs 0122 to 0130 of International Publication No. 2020 / 195360 are preferred examples.

[0078] The preferred methods for organic acids, polyvalent metal compounds, and metal complexes that can be used as coagulants are described below.

[0079] -Organic acids-

[0080] Organic acids can be exemplified by organic compounds that have acidic groups.

[0081] Examples of acidic groups include phosphate, phosphonic acid, hypophosphonic acid, sulfate, sulfonic acid, sulfinic acid, and carboxyl groups.

[0082] From the perspective of ink coagulation speed, the acidic group is preferably a phosphate group or a carboxyl group, and more preferably a carboxyl group.

[0083] Preferably, at least a portion of the acidic groups dissociate in the pretreatment solution.

[0084] Examples of organic compounds containing a carboxyl group include (meth)acrylic acid, poly(meth)acrylic acid, acetic acid, formic acid, benzoic acid, ethylene glycol, 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, pyrrolidone carboxylic acid, pyranone carboxylic acid, pyrrolic carboxylic acid, furan carboxylic acid, pyridine carboxylic acid, coumaric acid, thiophene carboxylic acid, and nicotinic acid.

[0085] From the viewpoint of ink coagulation speed, organic compounds with carboxyl groups are preferably carboxylic acids with a valence of 2 or higher (hereinafter also referred to as polycarboxylic acids), and more preferably dicarboxylic acids.

[0086] 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.

[0087] The organic acid is preferably low in pKa (e.g., 1.0 to 5.0). Thus, by contacting with an organic acid with a lower pKa, the surface charge of particles such as pigments and resin particles in the ink, which are dispersed and stabilized by weakly acidic functional groups such as carboxyl groups, can be reduced, thereby reducing dispersion stability.

[0088] The organic acid preferably has a low pKa, high solubility in water, and a valence of 2 or higher. Furthermore, the organic acid is more preferably characterized by a high buffering capacity in a pH region lower than the pKa of the functional group (e.g., carboxyl group) that stabilizes the particle dispersion in the ink.

[0089] -Polyvalent metal compounds-

[0090] As examples of multivalent metal compounds, multivalent metal salts can be cited.

[0091] Examples of polyvalent metal salts include organic acid polyvalent metal salts and inorganic acid polyvalent metal salts.

[0092] As a polyvalent metal salt of an organic acid, the polyvalent metal salts of the above-mentioned organic acids (e.g., formic acid, acetic acid, benzoic acid, etc.) are preferred.

[0093] As polyvalent metal salts of inorganic acids, polyvalent metal salts of nitrates, polyvalent metal salts of hydrochloric acid, or polyvalent metal salts of thiocyanate are preferred.

[0094] Examples of polyvalent metal salts include salts of alkaline earth metals (e.g., magnesium, calcium) from Group 2 of the periodic table, salts of transition metals (e.g., lanthanum) from Group 3 of the periodic table, salts of metals (e.g., aluminum) from Group 13 of the periodic table, and salts of lanthanides (e.g., neodymium).

[0095] As a multivalent metal salt, calcium salt, magnesium salt, or aluminum salt are preferred, with calcium salt or magnesium salt being more preferred.

[0096] As a polyvalent metal compound, a polyvalent metal salt of an organic acid is preferred, and a calcium salt or a magnesium salt of an organic acid is more preferred.

[0097] Preferably, at least a portion of the polyvalent metal compound dissociates into polyvalent metal ions and counterions in the pretreatment solution.

[0098] -Metal complex-

[0099] The metal complex preferably contains at least one metal element selected from the group consisting of zirconium, aluminum and titanium.

[0100] The metal complex is preferably a metal complex containing at least one ligand selected from the group consisting of acetate, acetylacetone, methyl acetoacetate, ethyl acetoacetate, octanediol, butoxyacetylacetone, lactate, ammonium lactate and triethanolamine.

[0101] Metal complexes are commercially available. Various organic ligands (especially multidentate ligands capable of forming metal chelating catalysts) are commercially available. Therefore, metal complexes can be prepared by combining commercially available organic ligands with metals.

[0102] Examples of metal complexes include zirconium tetraacetylacetone (e.g., ORGATIX ZC-150 manufactured by Matsumoto Fine Chemical Co., Ltd.), zirconium monoacetylacetone (e.g., ORGATIX ZC-540 manufactured by Matsumoto Fine Chemical Co., Ltd.), zirconium diacetylacetone (e.g., ORGATIX ZC-550 manufactured by Matsumoto Fine Chemical Co., Ltd.), zirconium monoacetylacetone (e.g., ORGATIX ZC-560 manufactured by Matsumoto Fine Chemical Co., Ltd.), zirconium acetate (e.g., ORGATIX ZC-115 manufactured by Matsumoto Fine Chemical Co., Ltd.), diisopropoxybis(acetylacetone)titanium (e.g., ORGATIX TC-100 manufactured by Matsumoto Fine Chemical Co., Ltd.), and titanium tetraacetylacetone (e.g., ORGATIX manufactured by Matsumoto Fine Chemical Co., Ltd.). TC-401”), dioctyloxybis(octyl glycol) titanium (e.g., “ORGATIX TC-200” manufactured by Matsumoto Fine Chemical Co., Ltd.), diisopropoxybis(ethyl acetoacetate) titanium (e.g., “ORGATIX TC-750” manufactured by Matsumoto Fine Chemical Co., Ltd.), zirconium tetraacetylacetonate (e.g., “ORGATIX ZC-700” manufactured by Matsumoto Fine Chemical Co., Ltd.), zirconium tributoxymonoacetylacetonate (e.g., “ORGATIX ZC-540” manufactured by Matsumoto Fine Chemical Co., Ltd.), zirconium monobutoxyacetylacetonate bis(ethyl acetoacetate) (e.g., “ORGATIX ZC-570” manufactured by Matsumoto Fine Chemical Co., Ltd.), zirconium dibutoxybis(ethyl acetoacetate) (e.g., “ORGATIX ZC-570” manufactured by Matsumoto Fine Chemical Co., Ltd.), zirconium dibutoxybis(ethyl acetoacetate) (e.g., “ORGATIX” manufactured by Matsumoto Fine Chemical Co., Ltd.) ZC-580”), aluminum triacetylacetonate (e.g., “ORGATIX AL-80” manufactured by Matsumoto Fine Chemical Co., Ltd.), ammonium titanium lactate (e.g., “ORGATIX TC-300” manufactured by Matsumoto Fine Chemical Co., Ltd.), titanium lactate (e.g., Matsumoto Fine Chemical Co., Ltd.).Matsumoto FineChemical Co., Ltd. manufactures "ORGATIX TC-310, 315", triethanolamine titanium (Matsumoto FineChemical Co., Ltd. manufactures "ORGATIX TC-400"), and zirconium chloride compounds (e.g., Matsumoto FineChemical Co., Ltd. manufactures "ORGATIX ZC-126").

[0103] The metal complex is preferably titanium ammonium lactate (e.g., ORGATIX TC-300 manufactured by Matsumoto Fine Chemical Co., Ltd.), titanium lactate (e.g., ORGATIX TC-310, 315 manufactured by Matsumoto Fine Chemical Co., Ltd.), titanium triethanolamine (e.g., ORGATIX TC-400 manufactured by Matsumoto Fine Chemical Co., Ltd.), or zirconium chloride compound (e.g., ORGATIX ZC-126 manufactured by Matsumoto Fine Chemical Co., Ltd.).

[0104] -Catonic polymer-

[0105] The pretreatment liquid of the present invention may further contain a cationic polymer as a coagulant.

[0106] The cationic polymer is preferably a homopolymer, copolymer, or condensation polymer of cationic monomers having primary to tertiary amino groups or quaternary ammonium groups. As a cationic polymer, it can be used in either the form of a water-soluble polymer or a water-insoluble polymer (i.e., latex particles).

[0107] Examples of cationic polymers include polyvinylpyridine salts, polyalkylaminoethyl acrylates, polyalkylaminoethyl methacrylates, polyvinylimazoles, polyethyleneimine, polybiguanidines, polyguanidines, polyallylamines, and their derivatives.

[0108] From the viewpoint of the viscosity of the pretreatment solution, a lower weight-average molecular weight of the cationic polymer is preferable. When the pretreatment solution is applied to the recording medium via inkjet printing, a weight-average molecular weight of 1,000 to 500,000 is preferred, more preferably 1,500 to 200,000, and even more preferably 2,000 to 100,000. A weight-average molecular weight of 1,000 or higher is advantageous from the viewpoint of agglomeration rate. A weight-average molecular weight of 500,000 or lower is advantageous from the viewpoint of ejection reliability. However, this is not a limitation when the pretreatment solution is applied to the recording medium by methods other than inkjet printing.

[0109] The content of coagulant in the pretreatment liquid is preferably 0.1% to 40% by mass relative to the total amount of the pretreatment liquid, more preferably 0.1% to 30% by mass, even more preferably 1% to 20% by mass, and even more preferably 1% to 10% by mass.

[0110] From the viewpoint of further improving the boiling resistance of the laminate, the coagulant preferably contains at least one selected from the group consisting of organic acids and organic acid polyvalent metal salts as polyvalent metal compounds.

[0111] In this case, the proportion of organic acid and organic acid polyvalent metal salt in the total amount of coagulant is preferably 50% to 100% by mass, more preferably 60% to 100% by mass, and even more preferably 80% to 100% by mass.

[0112] From the perspective of further improving the boiling resistance of the laminate, the coagulant is further preferably containing organic acids.

[0113] In this case, the content of organic acid in the total amount of coagulant is preferably 50% to 100% by mass, more preferably 60% to 100% by mass, and even more preferably 80% to 100% by mass.

[0114] <Carbamate Resins>

[0115] The pretreatment solution of the present invention contains a urethane resin, which comprises polyol units, polyisocyanate units, and polyalkylene glycol monoalkyl ether units.

[0116] The polyol unit, polyisocyanate unit, and polyalkylene glycol monoalkyl ether unit contained in the urethane resin may be only one type or two or more types.

[0117] In this invention,

[0118] Polyol units represent structural units derived from polyols.

[0119] Polyisocyanate units represent structural units derived from polyisocyanates.

[0120] The polyalkylene glycol monoalkyl ether unit refers to the structural unit derived from polyalkylene glycol monoalkyl ether.

[0121] Urea resins contain polyol units, polyisocyanate units, and polyalkylene glycol monoalkyl ether units. In other words, urethane resins are reaction products formed by the reaction of at least polyols, polyisocyanates, and polyalkylene glycol monoalkyl ethers.

[0122] Regarding polyols and polyisocyanates used to form urethane resins, for example, reference can be made to paragraphs 0031 to 0036 of Japanese Patent Application Publication No. 2001-247787, paragraphs 0033 to 0118 of International Publication No. 2016 / 052053, and paragraphs 0066 to 0223 of International Publication No. 2016 / 152254.

[0123] -Polyisocyanate units and polyisocyanates-

[0124] The urethane resin contains at least one polyisocyanate unit.

[0125] The preferred embodiments of the polyisocyanate unit and the preferred embodiments of the polyisocyanate used to form the polyisocyanate unit are described below.

[0126] Polyisocyanates can be polyisocyanates containing two isocyanate groups (i.e., diisocyanates (i.e., difunctional isocyanates)) or polyisocyanates containing three or more isocyanate groups (i.e., isocyanates with three or more functions).

[0127] As a polyisocyanate, a difunctional to hexafunctional isocyanate is preferred.

[0128] The polyisocyanate unit preferably comprises the following structural unit (P1).

[0129] [Chemical Formula 1]

[0130]

[0131] In structural unit (P1), L 1 This indicates a divalent organic group with 1 to 20 carbon atoms, and * indicates the bonding position.

[0132] As L 1 Specific examples can be given by removing two isocyanate groups (NCO groups) from the difunctional isocyanates involved in the following specific examples to form residues.

[0133] Specific examples of difunctional isocyanates are described below. However, difunctional isocyanates are not limited to the specific examples listed below.

[0134] [Chemical Formula 2]

[0135]

[0136] Furthermore, as a difunctional isocyanate, difunctional isocyanates derived from the above specific examples can also be used. Examples include Duranate (registered trademark) D101, D201, and A101 (manufactured by Asahi Kasei Corporation).

[0137] Furthermore, the isocyanate with three or more functions is preferably a reaction product of at least one of the group consisting of difunctional isocyanates and at least one of the group consisting of compounds with three or more active hydrogen groups (e.g., polyols with three or more functions, polyamines with three or more functions, and polythiols with three or more functions).

[0138] The number of moles (molecules) of the difunctional isocyanate reacting with the compound containing three or more active hydrogen groups is preferably 0.6 times or more, more preferably 0.6 to 5 times, even more preferably 0.6 to 3 times, and even more preferably 0.8 to 2 times, relative to the number of moles (equivalent number of active hydrogen groups) of the active hydrogen groups in the compound containing three or more active hydrogen groups.

[0139] As a difunctional isocyanate used to form isocyanates with three or more functions, the difunctional isocyanates mentioned in the specific examples above can be cited.

[0140] As compounds containing three or more active hydrogen groups for forming isocyanates with three or more functions, examples include the compounds described in paragraphs 0057 to 0058 of International Publication No. 2016 / 052053.

[0141] Examples of isocyanates with three or more functions include adduct-type isocyanates, isocyanurate-type isocyanates, and biuret-type isocyanates.

[0142] Commercially available products that are adductor-type isocyanates with three or more functionalities include Takenate (registered trademark) D-102, D-103, D-103H, D-103M2, P49-75S, D-110N, D-120N, D-140N, D-160N (and above, Mitsui Chemicals, Inc.), Desmodule (registered trademark) L75, UL57SP (Sumika Bayer Urethane Co., Ltd.), CORONATE (registered trademark) HL, HX, L (Nippon Polyurethane Industry Co., Ltd. (Toshoh Corporation)), and P301-75E (Asahi Kasei Corporation), etc.

[0143] Commercially available isocyanurate-type isocyanates with three or more functionalities include Takenate (registered trademark) D-127N, D-170N, D-170HN, D-172N, D-177N (and above, Mitsui Chemicals, Inc.), SUMIDURN3300, Desmodule (registered trademark) N3600, N3900, Z4470BA (and above, Sumika Bayer Urethane Co., Ltd.), CORONATE (registered trademark) HX, HK (and above, Nippon Polyurethane Industry Co., Ltd. (Toshoh Corporation)), and Duranate (registered trademark) TPA-100, TKA-100, TSA-100, TSS-100, TLA-100, TSE-100 (and above, Asahi Kasei Corporation), etc.

[0144] Commercially available biuret-type isocyanates with three or more functionalities include Takenate (registered trademark) D-165N, NP1100 (and above, Mitsui Chemicals, Inc.), Desmodule (registered trademark) N3200 (SumikaBayer Urethane Co., Ltd.), and Duranate (registered trademark) 24A-100 (Asahi Kasei Corporation).

[0145] At least one of the polyisocyanates may be a polyisocyanate containing a hydrophilic group. For reference on polyisocyanates containing hydrophilic groups, see paragraphs 0112-0118 and 0252-0254 of International Publication No. 2016 / 052053.

[0146] At least one of the polyisocyanates may be a polyisocyanate containing polymerizable groups. For reference to isocyanates containing polymerizable groups, see paragraphs 0084 to 0089, 0203 and 0205 of International Publication No. 2016 / 052053.

[0147] -Polyol Units and Polyols-

[0148] The urethane resin contains at least one polyol unit.

[0149] The preferred methods for the polyol unit and the preferred methods for the polyol used to form the polyol unit are described below.

[0150] Polyols can be polyols containing two hydroxyl groups (i.e., diols) or polyols containing three or more hydroxyl groups.

[0151] The polyol unit preferably comprises the following structural unit (P0).

[0152] [Chemical Formula 3]

[0153]

[0154] In structural unit (P0), L 0 * indicates a divalent organic group, and * indicates a bonding position.

[0155] In structural unit (P0), L 0 The divalent organic group can be a group containing carbon and hydrogen atoms, or a group containing carbon and hydrogen atoms and heteroatoms (e.g., oxygen, nitrogen, sulfur, etc.).

[0156] By L 0 The divalent organic group may include at least one of a hydrophilic group and a polymerizable group.

[0157] As L 0 Specific examples can be given by removing hydrogen atoms from each of the two hydroxyl groups in the diols exemplified below.

[0158] The following are specific examples of diols as preferred forms of polyols, but polyols are not limited to the following specific examples.

[0159] [Chemical Formula 4]

[0160]

[0161] In compounds (12) to (15), nC7H 15 nC9H 19 nC 11 H 23 and nC 17 H 35 They represent n-heptyl, n-nonyl, n-undecyl, and n-heptadecyl, respectively.

[0162] Compound (16)PPG is polypropylene glycol, and n is the number of repetitions.

[0163] Compound (16-2)PEG is polyethylene glycol, and n is the number of repetitions.

[0164] Compound (17)PEs is a polyester diol, where n is the repetition number, and Ra and the two Rb are independently divalent hydrocarbon groups with 2 to 25 carbon atoms. The n Ra in compound (17)PEs can be the same or different. The (n+1) Rb in compound (17)PEs can be the same or different.

[0165] Compound (18)PC is a polycarbonate diol, where n is the repetition number, and the (n+1) Rcs are each independently an alkylene group with 2 to 12 carbon atoms (preferably 3 to 8, more preferably 3 to 6). The (n+1) Rcs in compound (18)PC can be the same or different.

[0166] Compound (19)PCL is polycaprolactone diol, n and m are the repeating numbers, and Rd is an alkylene group with 2 to 25 carbon atoms.

[0167] The polyol units in the urethane resin preferably include polycarbonate diol units. This further improves the boiling resistance of the laminate.

[0168] In this case, the proportion of polycarbonate diol units in the total amount of polyol units is preferably 50% to 100% by mass, more preferably 60% to 100% by mass, and even more preferably 80% to 100% by mass.

[0169] The polycarbonate diol used to form the polycarbonate diol unit is, for example, the compound (18) PC mentioned above.

[0170] As a polycarbonate diol, commercially available products can be used.

[0171] Commercially available products include DURANOL T5652 (manufactured by Asahi Kasei Corporation), DURANOL T5651 (manufactured by Asahi Kasei Corporation), DURANOL T6002 (manufactured by Asahi Kasei Corporation), DURANOL T6001 (manufactured by Asahi Kasei Corporation), BENEBiOL HS0830B (manufactured by Mitsubishi Chemical Corporation), BENEBiOL HS0840H (manufactured by Mitsubishi Chemical Corporation), BENEBiOL NL1010DB (manufactured by Mitsubishi Chemical Corporation), and BENEBiOL NL2010DB (manufactured by Mitsubishi Chemical Corporation).

[0172] The polyol units in the urethane resin preferably include polycarbonate diol units. This further improves the boiling resistance of the laminate.

[0173] In this case, the proportion of polycarbonate diol units in the total amount of polyol units is preferably 50% to 100% by mass, more preferably 60% to 100% by mass, and even more preferably 80% to 100% by mass.

[0174] - Polyalkylene glycol monoalkyl ether units and polyalkylene glycol monoalkyl ethers-

[0175] The urethane resin contains at least one polyalkylene glycol monoalkyl ether unit.

[0176] Examples of polyalkylene glycol monoalkyl ethers used to form polyalkylene glycol monoalkyl ether units include polymers formed by the addition polymerization of ethylene oxide or propylene oxide with any alcohol (e.g., methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, etc.).

[0177] Specific examples of polyalkylene glycol monoalkyl ethers include polyethylene glycol monomethyl ether, polyethylene glycol monoethyl ether, polyethylene glycol monopropyl ether, polyethylene glycol monobutyl ether, polypropylene glycol monomethyl ether, polypropylene glycol monoethyl ether, polypropylene glycol monopropyl ether, and polypropylene glycol monobutyl ether.

[0178] From the viewpoint of further improving the boiling resistance of the laminate, the content of polyalkylene glycol monoalkyl ether units relative to the total amount of urethane resin is preferably 2% to 30% by mass, more preferably 3% to 25% by mass, and even more preferably 5% to 20% by mass.

[0179] From the viewpoint of further improving the boiling resistance of the laminate, when the number average molecular weight of the polyalkylene glycol monoalkyl ether used to form the polyalkylene glycol monoalkyl ether unit is set as a and the number average molecular weight of the urethane resin is set as b, the (a / b)×100 is preferably 1.0 to 30.0, more preferably 1.5 to 25.0, even more preferably 2.5 to 20.0, and even more preferably 2.5 to 16.0.

[0180] The number-average molecular weight (hereinafter also referred to as "molecular weight (a)") of the polyalkylene glycol monoalkyl ether used to form the polyalkylene glycol monoalkyl ether unit is preferably 500 to 20,000, more preferably 500 to 10,000, even more preferably 700 to 7,000, and even more preferably 750 to 5,000.

[0181] The molecular weight (a) is determined by hydrolyzing the urethane resin and separating the polyalkylene glycol monoalkyl ether from the obtained hydrolysate, and the number-average molecular weight of the separated polyalkylene glycol monoalkyl ether is determined by the determination method described later.

[0182] Here, the hydrolysis of the urethane resin is carried out by adding an alkali to an aqueous solution of the urethane resin and heating it.

[0183] The separation of polyalkylene glycol monoalkyl ethers from urethane resin hydrolysates is carried out by adding an organic solvent to the urethane resin hydrolysates to extract components other than polyalkylene glycol monoalkyl ethers.

[0184] The number-average molecular weight (hereinafter also referred to as "molecular weight (b)") of the urethane resin is preferably 3,000 to 200,000, more preferably 4,000 to 100,000, even more preferably 5,000 to 80,000, and even more preferably 10,000 to 50,000.

[0185] In this invention, the number-average molecular weight (e.g., molecular weight (a) and molecular weight (b) above) and weight-average molecular weight were determined by gel permeation chromatography (GPC). An HLC-8220 GPC (manufactured by Tosoh Corporation) was used as the column, with three TSKgel SuperHZM-H, TSKgel SuperHZ4000, and TSKgel SuperHZ2000 (all trade names manufactured by Tosoh Corporation) connected in series. THF (tetrahydrofuran) was used as the eluent. Furthermore, the sample concentration was set to 0.45% by mass, the flow rate to 0.35 ml / min, the sample injection volume to 10 μl, and the measurement temperature to 40°C. A differential refractive index detector was used for the measurement. Furthermore, the calibration curves were prepared based on eight samples from Tosoh Corporation: “TSK standard, polystyrene”: “F-40”, “F-20”, “F-4”, “F-1”, “A-5000”, “A-2500”, “A-1000”, and “n-propylbenzene”.

[0186] The urethane resin can be a water-soluble urethane resin or a water-insoluble urethane resin (i.e., urethane resin particles).

[0187] From the viewpoint of improving the strength of the layer formed by the pretreatment liquid, urethane resin is preferably urethane resin particles.

[0188] In this invention, "water solubility" refers to the property of dissolving more than 1g of water at 25°C with 100g of water.

[0189] In this invention, "water insoluble" refers to the property that the amount of water that can be dissolved in 100g of water at 25°C is less than 1g.

[0190] 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 50 nm to 150 nm.

[0191] In addition, the average particle size is determined as follows: using a particle size distribution measuring device, such as the Nikkiso Co., Ltd. product name "NANOTRAC UPA-EX150", the volume average particle size is determined by dynamic light scattering method.

[0192] The content of urethane resin in the pretreatment solution is preferably 1% to 30% by mass relative to the total amount of the pretreatment solution, more preferably 3% to 20% by mass, and even more preferably 5% to 15% by mass.

[0193] (Organic solvents)

[0194] The pretreatment solution of the present invention may contain at least one organic solvent.

[0195] There is no limitation on the types of organic solvents; for example, the following can be cited:

[0196] Monools with 1 to 4 carbon atoms;

[0197] Diols such as 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2-buten-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;

[0198] Triols such as glycerol, 1,2,6-hexanetriol, and trimethylolpropane;

[0199] alkylene glycols such as ethylene glycol and propylene glycol;

[0200] Ethylene glycol monoalkyl ethers, propylene glycol monoalkyl ethers, and other alkylene glycol monoalkyl ethers;

[0201] Diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, dipropylene glycol, polyoxyethylene polyoxypropylene glycol, and other polyalkylene glycols;

[0202] Diethylene glycol monoalkyl ethers, triethylene glycol monoalkyl ethers, tripropylene glycol monoalkyl ethers, polyoxypropylene glycerol ethers, and other polyalkylene glycol ethers;

[0203] 2-Pyrrolidone, N-methyl-2-pyrrolidone, etc.

[0204] The content of organic solvent relative to the total amount of pretreatment liquid is preferably 1% to 20% by mass, more preferably 3% to 10% by mass.

[0205] <surfactants>

[0206] The pretreatment solution of the present invention may contain at least one surfactant.

[0207] There are no particular restrictions on the type of surfactant; it can be any of the following: anionic surfactants, cationic surfactants, betaine surfactants, and nonionic surfactants. Furthermore, examples of surfactants include acrylic surfactants, fluorinated surfactants, and silicone surfactants.

[0208] The surfactant content relative to the total amount of the pretreatment solution is preferably 0.1% to 5% by mass, more preferably 0.2% to 1% by mass.

[0209] <Other Ingredients>

[0210] The pretreatment solution of the present invention may contain other components besides those mentioned above, as needed.

[0211] Other components that can be contained in the pretreatment solution include known additives such as solid wetting agents, colloidal silica, inorganic salts, anti-fading agents, emulsion stabilizers, penetration enhancers, ultraviolet absorbers, preservatives, mildew inhibitors, pH adjusters, viscosity adjusters, rust inhibitors, chelating agents, and water-soluble polymers (e.g., the water-soluble polymers described in paragraphs 0026 to 0080 of Japanese Patent Application Publication No. 2013-001854).

[0212] <Physical Properties>

[0213] The pH of the pretreatment solution is preferably 2.0 to 7.0, more preferably 2.0 to 4.0. The pH is measured using a pH meter at 25°C, for example using a pH meter (model "HM-31") manufactured by DKK-TOA CORPORATION.

[0214] From the viewpoint of the coatability of the pretreatment solution, the viscosity of the pretreatment solution is preferably 0.5 mPa·s to 10 mPa·s, more preferably 1 mPa·s to 5 mPa·s. The viscosity is the value measured using a viscometer at 25°C. The viscosity is measured using a viscometer at 25°C, for example, using a TV-22 type viscometer manufactured by Toki Sangyo Co., Ltd.

[0215] The surface tension of the pretreatment liquid is preferably below 60 mN / m, 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 25°C. The surface tension is measured using a surface tension meter at 25°C, for example, using an automatic surface tension meter (product name "CBVP-Z") manufactured by Kyowa Interface Science Co., Ltd., measured by the plate method.

[0216] [Ink Group]

[0217] The ink assembly of the present invention contains:

[0218] The pretreatment solution of the present invention described above; and

[0219] The first ink is an inkjet ink containing water and urethane resin.

[0220] The ink group of the present invention contains the pretreatment liquid of the present invention described above, and therefore has the same effect as the pretreatment liquid of the present invention described above.

[0221] <First Ink>

[0222] The ink group of the present invention contains a first ink, which is an inkjet ink containing water and urethane resin.

[0223] The first ink can be of only one type or of two or more types.

[0224] (water)

[0225] The first ink contains water.

[0226] The water content relative to the total amount of the first ink 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.

[0227] The upper limit of the water content relative to the total amount of the first ink can be appropriately determined based on the content of other components, for example, 99% by mass, preferably 95% by mass, and more preferably 90% by mass.

[0228] (Carbamate resin)

[0229] The first ink contains at least one type of urethane resin.

[0230] The urethane resin in the coloring ink can be one type or two or more types.

[0231] The urethane resin in the coloring ink and the urethane resin in the pretreatment solution can be the same type of urethane resin or different types of urethane resin.

[0232] The urethane resin in the first ink is preferably a polyester urethane resin with ester bonds in its main chain, a polycarbonate urethane resin with carbonate bonds in its main chain, or a polyether urethane resin with ether bonds in its main chain.

[0233] The urethane resin in the first ink can be either a water-soluble urethane resin or a water-insoluble urethane resin (i.e., urethane resin particles).

[0234] From the viewpoint of improving the strength of the layer formed by the first ink, urethane resin is preferably urethane resin particles.

[0235] When the urethane resin in the first ink is urethane resin particles, from the viewpoint of spraying stability, 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.

[0236] The average particle size of the urethane resin particles in the first ink can be determined by the same method as that used for the average particle size of the urethane resin particles in the pretreatment solution.

[0237] The urethane resin in the first ink can be any of anionic, cationic, or nonionic.

[0238] From the viewpoint of improving the storage stability of the first ink, anionic urethane resin is preferred.

[0239] The weight-average molecular weight (Mw) of the urethane resin in the first 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.

[0240] The weight-average molecular weight of the urethane resin in the first ink can be determined using the same method as that used for the urethane resin in the pretreatment solution.

[0241] The urethane resin in the first ink can be a commercially available product.

[0242] As commercially available products, examples include the SUPERFLEX series manufactured by DKS Co. Ltd., the PERMARIN UA and UCOAT series manufactured by Sanyo Chemical Industries, Ltd., the TAKELAC series manufactured by Mitsui Chemicals, Inc., and the PUE series manufactured by Muraya Institute of Chemistry.

[0243] The content of urethane resin in the first ink is preferably 1% to 20% by mass relative to the total amount of the first ink, more preferably 2% to 15% by mass, and even more preferably 2% to 10% by mass.

[0244] (pigment)

[0245] The first ink preferably contains pigment (i.e., at least one of coloring pigment and white pigment), and more preferably contains white pigment.

[0246] The first ink is further preferably a white ink containing white pigment.

[0247] (White pigment)

[0248] Examples of inorganic pigments that can be used as white pigments include titanium dioxide, barium sulfate, calcium carbonate, silicon dioxide, zinc oxide, zinc sulfide, mica, talc, and pearl.

[0249] The white pigment is preferably titanium dioxide, barium sulfate, calcium carbonate or zinc oxide, and more preferably titanium dioxide.

[0250] From the viewpoint of concealment, the average primary particle size of the white pigment is preferably 150 nm or more, more preferably 200 nm or more. Furthermore, from the viewpoint of ink ejectibility, the average primary particle size of the white pigment is preferably 400 nm or less, more preferably 350 nm or less.

[0251] In this invention, the average primary particle size of the white pigment is a value measured using a transmission electron microscope (TEM). Specifically, it is obtained by selecting any 50 white pigments present within the field of view observed by the TEM, measuring the primary particle size of each of the 50 pigments, and then averaging the results. The transmission electron microscope can be a JEOL Ltd. 1200EX transmission electron microscope.

[0252] From the viewpoint of image density and ejectibility, the content of white pigment relative to the total amount of the first ink is preferably 2% to 25% by mass, more preferably 5% to 25% by mass, and even more preferably 10% to 20% by mass.

[0253] In addition, the first ink can replace white pigment, or contain coloring pigment on the basis of white pigment.

[0254] For the type and content of coloring pigments in the first ink, please refer to the items for the second ink.

[0255] (Pigment dispersion resin)

[0256] The first ink may contain at least one pigment dispersion resin.

[0257] In this invention, pigment dispersion resin refers to a resin that has the function of dispersing pigments.

[0258] Pigment dispersion resins can be random copolymers or block copolymers.

[0259] Furthermore, pigment dispersion resins can also have cross-linked structures.

[0260] The first ink can be prepared using a pigment dispersion containing pigments and pigment dispersing resins.

[0261] The pigment dispersion resin is preferably a random copolymer.

[0262] Random copolymers preferably contain structural units derived from hydrophobic monomers and structural units derived from monomers containing anionic groups (hereinafter referred to as "monomers containing anionic groups"). From the viewpoint of dispersion stability, the ratio (x:y) of structural unit x derived from hydrophobic monomers to structural unit y derived from monomers containing anionic groups is preferably 8:1 to 1:1.

[0263] The structural units derived from hydrophobic monomers contained in random copolymers can be of only one type or more types.

[0264] The structural units derived from anionic monomers contained in random copolymers can be of only one type or more types.

[0265] The hydrophobic monomer is preferably a monomer containing a hydrocarbon group having 4 or more carbon atoms, more preferably an olefinic unsaturated monomer containing a hydrocarbon group having 4 or more carbon atoms, and even more preferably a (meth)acrylate containing a hydrocarbon group having 4 or more carbon atoms. The hydrocarbon group can be any of a chain hydrocarbon group, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group. The hydrocarbon group more preferably has 6 or more carbon atoms, and even more preferably 10 or more. The upper limit for the number of carbon atoms in the hydrocarbon group is, for example, 20.

[0266] Examples of (meth)acrylates having a chain-like 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 chain-like hydrocarbon group more preferably has 6 or more carbon atoms, further preferably 8 or more, and particularly preferably 12 or more. Among these, the olefinically unsaturated monomer having a chain-like hydrocarbon group having 4 or more carbon atoms is preferably lauryl (meth)acrylate or stearyl (meth)acrylate.

[0267] Examples of (meth)acrylates having an alicyclic hydrocarbon group having four or more carbon atoms include (meth)acrylate (bicyclo[2.2.1]heptyl-2) ester, (meth)acrylate 1-adamantyl ester, (meth)acrylate 2-adamantyl ester, (meth)acrylate 3-methyl-1-adamantyl ester, (meth)acrylate 3,5-dimethyl-1-adamantyl ester, (meth)acrylate 3-ethyladamantyl ester, (meth)acrylate 3-methyl-5-ethyl-1-adamantyl ester, (meth)acrylate 3,5,8-triethyl-1-adamantyl ester, (meth)acrylate 3,5-dimethyl-8-ethyl-1-adamantyl ester, and (meth)acrylate 2-methyl-2-adamantyl The alicyclic esters include 2-ethyl-2-adamantyl ester, 3-hydroxy-1-adamantyl ester, octahydro-4,7-methyl-indene-5-yl ester, octahydro-4,7-methyl-indene-1-yl methyl ester, 1-menthol ester, tricyclodecyl ester, 3-hydroxy-2,6,6-trimethyl-bicyclo[3.1.1]heptyl ester, 3,7,7-trimethyl-4-hydroxy-bicyclo[4.1.0]heptyl ester, norborneol ester, isoborneol ester, 2,2,5-trimethylcyclohexyl ester, and cyclohexyl ester. The alicyclic hydrocarbon group preferably has 6 or more carbon atoms. Among them, the olefinic unsaturated monomer having an alicyclic hydrocarbon group with 4 or more carbon atoms is preferably isobornyl methacrylate or cyclohexyl methacrylate.

[0268] Examples of (meth)acrylates having an aromatic hydrocarbon group having 4 or more carbon atoms include 2-naphthyl (meth)acrylate, phenoxyethyl (meth)acrylate, and benzyl (meth)acrylate. Among these, the olefinic unsaturated monomer having an aromatic hydrocarbon group having 4 or more carbon atoms is preferably benzyl (meth)acrylate.

[0269] Hydrophobic monomers may also contain (meth)acrylates with a hydrocarbon group having 1 to 3 carbon atoms.

[0270] 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.

[0271] From the viewpoint of improving the dispersion stability of white pigments, the structural units derived from hydrophobic monomers contained in the pigment dispersion resin preferably include structural units derived from (meth)acrylates with a chain hydrocarbon group having 4 or more carbon atoms and structural units derived from (meth)acrylates with an aromatic hydrocarbon group having 4 or more carbon atoms.

[0272] Examples of anionic groups in monomers containing anionic groups include carboxyl groups, salts of carboxyl groups, sulfonyl groups, salts of sulfonyl groups, phosphate groups, salts of phosphate groups, phosphonic acid groups, and salts of phosphonic acid groups.

[0273] Counterions in salts include: alkali metal ions such as sodium, potassium, and lithium ions; alkaline earth metal ions such as calcium and magnesium ions; and ammonium ions.

[0274] The anionic group is preferably a carboxyl group or a salt of a carboxyl group.

[0275] Examples of carboxyl-containing monomers include (meth)acrylic acid, β-carboxyethyl acrylate, fumaric acid, itaconic acid, maleic acid, and crotonic acid.

[0276] From the viewpoint of dispersion stability, monomers containing anionic groups are preferably (meth)acrylic acid or β-carboxyethyl acrylate, and more preferably (meth)acrylic acid.

[0277] The ratio of white pigment content to pigment dispersion resin content, based on mass, 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.

[0278] From the viewpoint of dispersion stability, the acid value of the pigment dispersion resin is preferably 100 mg KOH / g or higher, and more preferably 120 mg KOH / g or higher.

[0279] On the other hand, from the viewpoint of setting the acid value of the first ink to 8 mg KOH / g or less, the acid value of the pigment dispersion resin is preferably 300 mg KOH / g or less, and more preferably 230 mg KOH / g or less.

[0280] When the first ink contains pigment dispersion resin, the content of pigment dispersion resin relative to the total amount of the first ink is preferably 0.1% to 10% by mass, more preferably 0.3% to 5% by mass, and even more preferably 0.5% to 2.5% by mass.

[0281] (Organic solvents)

[0282] The first ink preferably contains an organic solvent.

[0283] As a result, ejection stability is improved.

[0284] The organic solvent contained in the coloring ink can be one type or two or more types.

[0285] As an organic solvent, examples can be made of organic solvents that are the same as those contained in the pretreatment solution described above.

[0286] From the viewpoint of spray stability, the organic solvent preferably contains at least one selected from the group consisting of alkylene glycols and alkylene glycol monoalkyl ethers.

[0287] The content of organic solvent relative to the total amount of the first ink is preferably 10% to 40% by mass, more preferably 15% to 30% by mass.

[0288] (additive)

[0289] The first ink may contain additives such as surfactants, water-soluble resins, co-sensitizers, ultraviolet absorbers, antioxidants, anti-fading agents, conductive salts, and alkaline compounds, as needed.

[0290] (physical properties)

[0291] From the viewpoint of improving ejection stability, the pH (25°C) of the first ink is preferably 7 to 10, more preferably 7.5 to 9.5. The pH of the coloring ink can be measured using the same method as that used for the pH of the pretreatment solution.

[0292] The viscosity (at 25°C) of the first ink is preferably 0.5 mPa·s to 30 mPa·s, more preferably 2 mPa·s to 20 mPa·s, even more preferably 2 mPa·s to 15 mPa·s, and even more preferably 3 mPa·s to 10 mPa·s. The viscosity of the coloring ink can be measured using the same method as that used for the viscosity of the pretreatment solution.

[0293] The surface tension (at 25°C) of the first ink is preferably 60 mN / m or less, more preferably 20 mN / m to 50 mN / m, and even more preferably 30 mN / m to 45 mN / m.

[0294] Surface tension can be measured using the same method as in the pretreatment solution.

[0295] <Second Ink>

[0296] The ink group of the present invention may contain a second ink, which is an inkjet ink containing water, coloring pigment and urethane resin.

[0297] One preferred embodiment of the ink group of the present invention includes:

[0298] The pretreatment solution of the present invention;

[0299] As the first ink for white ink, it is an inkjet ink containing water, white pigment, and urethane resin; and

[0300] The second ink, which is a coloring ink, is an inkjet ink containing water, coloring pigments, and urethane resin.

[0301] In this invention, coloring pigment refers to colored pigment or black pigment.

[0302] In this invention, coloring ink refers to colored ink (e.g., cyan ink, magenta ink, yellow ink, etc.) or black ink.

[0303] The preferred embodiment of the second ink is the same as that of the first ink, except that it contains coloring pigment as an essential component.

[0304] For example, the preferred methods for the water content, type of urethane resin, and content of urethane resin in the second ink are the same as those for the water content, type of urethane resin, and content of urethane resin in the first ink.

[0305] (Coloring pigments)

[0306] Coloring pigments are either commercially available organic or inorganic pigments.

[0307] As coloring pigments, examples include those described in Seishiro Itō's "Encyclopedia of Pigments" (published in 2000), W. Herbst and K. Hunger's "Industrial Organic Pigments," and Japanese Patent Application Publication Nos. 2002-12607, 2002-188025, 2003-26978, and 2003-342503.

[0308] Furthermore, the coloring pigment can be a water-insoluble pigment that can be dispersed in water by a dispersant, or it can be a self-dispersing pigment.

[0309] Self-dispersible pigments are pigments that can be dispersed in water even without the use of a dispersant.

[0310] Self-dispersible pigments are, for example, compounds selected from the group consisting of hydrophilic groups such as carbonyl, hydroxyl, carboxyl, sulfonyl, and phosphate groups and their salts, which are directly or chemically bonded to the surface of the pigment via other groups.

[0311] There are no particular limitations on the types of coloring pigments; for example, cyan pigment, magenta pigment, yellow pigment, and black pigment can be mentioned.

[0312] From the viewpoint of image density and the ejectibility of the second ink, the content of coloring pigment relative to the total amount of the second ink is preferably 1% to 20% by mass, more preferably 1% to 15% by mass, and even more preferably 1% to 10% by mass.

[0313] [Image recording method]

[0314] The image recording method of the present invention is an image recording method using the ink group of the present invention described above.

[0315] The image recording method of the present invention includes:

[0316] The process of applying the pretreatment liquid of the ink group of the present invention to a non-permeable substrate (hereinafter also referred to as the "pretreatment liquid application process"); and

[0317] The process of applying the first ink of the ink group of the present invention to a non-permeable substrate on which a pretreatment liquid has been applied by inkjet recording (hereinafter also referred to as the "first ink application process").

[0318] The image recording method of the present invention uses the ink group of the present invention described above, and therefore achieves the same effect as the ink group of the present invention described above.

[0319] <Pretreatment solution application process>

[0320] The pretreatment liquid application process is a process of applying the pretreatment liquid (i.e., the pretreatment liquid of the present invention) from the ink group of the present invention onto a non-permeable substrate.

[0321] (Non-permeable substrate)

[0322] In this invention, the non-permeability of the non-permeable substrate refers to the property that the water absorption rate is less than 2.5% over 24 hours as determined by ASTM D570-98 (2018). Here, the "%" used as the unit of water absorption rate is based on mass. The aforementioned water absorption rate is preferably less than 1.0%, more preferably less than 0.5%.

[0323] Materials that can be used as non-permeable substrates include, for example, 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 alcohol acetal, nylon, acrylic resin, etc.).

[0324] The non-permeable substrate is preferably made of resin. That is, the non-permeable substrate is preferably a resin substrate.

[0325] From a general perspective, the preferred materials for non-permeable substrates are polypropylene, polyethylene, polyethylene terephthalate, nylon, acrylic resin, or polyvinyl chloride.

[0326] The shape of the non-permeable substrate is preferably sheet (film) or plate. Examples of non-permeable substrates with this shape include glass plates, metal plates, resin sheets (resin films), paper laminated with plastic, paper laminated or vapor-deposited with metal, and plastic sheets (plastic films) laminated or vapor-deposited with metal.

[0327] As a non-permeable substrate made of resin, examples include resin sheets (resin films), and more specifically, flexible packaging materials for packaged food and floor guide panels in large retail stores.

[0328] In addition to sheet-like (film-like) or plate-like non-permeable substrates, textiles (fabricated fabrics) and non-woven fabrics formed from non-permeable fibers can also be cited as examples of non-permeable substrates.

[0329] The thickness of the non-permeable 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.

[0330] For non-permeable substrates, hydrophilic treatment can be performed. Examples of hydrophilic treatments include corona treatment, plasma treatment, frame treatment, heat treatment, abrasion treatment, light irradiation treatment (e.g., UV treatment), and flame treatment, but are not limited to these. Corona treatment can be performed, for example, using a corona master (product name "PS-10S", manufactured by Shinko Electric & Instrumentation Co., Ltd.). The conditions for corona treatment should be appropriately selected based on the type of non-permeable substrate.

[0331] Non-permeable substrates can be transparent non-permeable substrates.

[0332] Here, transparency means that the transmittance of visible light with wavelengths of 400 nm to 700 nm is 80% or more (preferably 90% or more).

[0333] When the non-permeable substrate is a transparent non-permeable substrate, the image can be easily visually identified from the non-recording side of the non-permeable substrate.

[0334] For example, when the non-permeable substrate is a transparent non-permeable substrate, and an image is recorded by sequentially applying a pretreatment liquid, a second ink as a coloring ink, and a first ink as a white ink to the non-permeable substrate, it is easy to visually identify the colored image (e.g., a pattern image such as a character or graphic) against a white image (e.g., a solid image) from the non-recording side of the non-permeable substrate.

[0335] (Pretreatment solution application)

[0336] There are no particular limitations on the method of applying the pretreatment solution; known methods such as coating, immersion, and inkjet recording can be cited.

[0337] As a coating method, known coating methods include those using rod coaters, extrusion die coaters, air knife coaters, scraper coaters, bar coaters, doctor blade coaters, extrusion coaters, and reverse roller coaters.

[0338] (Heating and drying of the pretreatment solution)

[0339] The pretreatment liquid application process may include the steps of applying a pretreatment liquid to a non-permeable substrate and heating and drying the pretreatment liquid applied to the non-permeable substrate.

[0340] As an apparatus for heating and drying pretreated liquids, examples include known heating devices such as heaters, known air supply devices such as dryers, and apparatuses combining these.

[0341] Examples of methods for heating and drying a pretreatment liquid include: heating the non-permeable substrate from the side opposite to the surface to which the pretreatment liquid is applied using a heater; blowing warm air or hot air onto the surface of the non-permeable substrate to which the pretreatment liquid is applied; heating the non-permeable substrate from the surface to which the pretreatment liquid is applied or from the side opposite to the surface to which the pretreatment liquid is applied using an infrared heater; and methods combining these methods.

[0342] The heating temperature for heating and drying the pretreatment liquid is preferably 35°C or higher, 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.

[0343] There is no particular limitation on the heating and drying time, but it is preferably 0.5 seconds to 60 seconds, more preferably 0.5 seconds to 20 seconds, and even more preferably 0.5 seconds to 10 seconds.

[0344] <First Ink Application Process>

[0345] The first ink application process is a process of applying the first ink to a non-permeable substrate that has been treated with a pretreatment solution by inkjet recording.

[0346] Through this process, on a non-permeable substrate, the components in the first ink are coagulated by the coagulant in the pretreatment solution, thereby obtaining an image.

[0347] (The application of the first ink)

[0348] There are no particular restrictions on the way ink is ejected in inkjet recording. It can be any of the known methods, such as charge control method that uses electrostatic induction to eject ink, on-demand inkjet method (pressure pulse method) that uses the vibration pressure of piezoelectric elements, acoustic inkjet method that converts electrical signals into sound beams that irradiate the ink and uses radiation pressure to eject ink, and thermal inkjet method (Bubble Jet (registered trademark)) that heats the ink to form bubbles and uses the resulting pressure.

[0349] As an inkjet recording method, the inkjet recording method described in Japanese Patent Application Publication No. 54-59936 can be used particularly effectively. In this inkjet recording method, the ink undergoes a rapid volume change under the influence of heat energy, and the force generated by this change in state causes the ink to be ejected from the nozzle. As an inkjet recording method, the method described in paragraphs 0093 to 0105 of Japanese Patent Application Publication No. 2003-306623 can also be used.

[0350] The first ink is applied to a non-permeable substrate by inkjet recording, which is performed by ejecting the first ink from the nozzle of the inkjet head.

[0351] As for inkjet head configurations, there are: a reciprocating mode in which a short strip-shaped serial head scans and records simultaneously along the width of the medium being recorded; and a linear mode in which a line inkjet head uses recording elements arranged corresponding to the entire area of ​​one side of the medium being recorded.

[0352] In the inline method, by scanning the recording medium along a direction intersecting the arrangement direction of the recording elements, images can be recorded across the entire surface of the recording medium. The inline method eliminates the need for a transport system such as a carriage for scanning short, strip-shaped inkjet heads, as in the reciprocating method. Furthermore, compared to the reciprocating method, the inline method eliminates the need for carriage movement and complex scanning control between the recording medium and the recording medium; only the recording medium needs to move. Therefore, the linear method achieves higher image recording speeds compared to the reciprocating method.

[0353] The first ink is preferably applied using an inkjet head with a resolution of 300 dpi or higher (more preferably 600 dpi or higher, and even more preferably 800 dpi or higher). Here, dpi is an abbreviation for dots per inch, and 1 inch is 2.54 cm.

[0354] From the viewpoint of obtaining high-definition images, the amount of ink ejected from the first ink is preferably 1 pL (picoliter) to 10 pL, more preferably 1.5 pL to 6 pL.

[0355] (Heat drying)

[0356] The first ink application process may include:

[0357] The step of applying the first ink to a non-permeable substrate coated with a pretreatment solution by inkjet printing; and

[0358] The step of heating and drying the first ink.

[0359] There are no particular limitations on the methods of heating and drying, such as infrared (IR) drying, warm air drying, and heating and drying using heating devices (e.g., heaters, hot plates, furnaces, etc.).

[0360] As a method of heating and drying, it can also be a combination of two or more of them.

[0361] Heat drying can be performed by heating the first ink from at least one side of the non-permeable substrate, either the image recording side or the non-image recording side.

[0362] The heating temperature in the heating and drying of the first ink 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.

[0363] There is no particular limit to the upper limit of the heating temperature, but it is preferably 100°C, and more preferably 90°C.

[0364] There is no particular limitation on the heating time when drying the first ink, but it is preferably 1 second to 180 seconds, more preferably 1 second to 120 seconds, and even more preferably 1 second to 60 seconds.

[0365] <Implementation Method>

[0366] One embodiment of the image recording method of the present invention is an image recording method using an ink group comprising the first ink and the second ink described above.

[0367] The image recording method involved in this embodiment includes:

[0368] The process of applying the pretreatment liquid of the ink group of the present invention to a non-permeable substrate; and

[0369] The process of applying the first ink and the second ink of the ink group of the present invention to a non-permeable substrate that has been treated with a pretreatment solution by inkjet recording.

[0370] The process of applying a pretreatment solution to a non-permeable substrate is as described above.

[0371] According to the image recording method of this embodiment, intermediate color images can be recorded using a first ink (e.g., white ink) and a second ink (e.g., colored ink).

[0372] Examples of intermediate color images include colored images (e.g., patterned images of characters, graphics, etc.) with a white image (e.g., a solid image) as a background.

[0373] The order in which the first ink (e.g., white ink) and the second ink (e.g., coloring ink) are applied can be arbitrary.

[0374] For example, when visually recognizing an image from the image recording surface side, a first ink as white ink and a second ink as coloring ink are sequentially applied.

[0375] When visually recognizing an image from the non-recording side of an image through a non-permeable substrate, a coloring ink as a second ink and a white ink as a first ink are sequentially applied. Thus, for example, an intermediate color image is recorded on a non-permeable substrate, which sequentially includes a pattern image (characters, graphics, etc.) recorded by the coloring ink and a solid image-like white image recorded by the white ink in a manner that covers the pattern image.

[0376] In the process of applying the first ink and the second ink, the method of applying the first ink and the second ink respectively by inkjet recording is as described above.

[0377] Furthermore, the process of applying the first ink and the second ink may include a step of heating and drying the ink after applying at least one of the first ink and the second ink. Preferred conditions for heating and drying are as described above.

[0378] For example, as a method of this process, one could describe a method in which the coloring ink, as the second ink, is applied, the white ink, as the first ink, is applied, and then dried sequentially. In this method, the second ink can be heated and dried between the application of the second ink and the application of the first ink, or the second ink can be dried without heating.

[0379] [Method for manufacturing laminates]

[0380] The method for manufacturing the laminate of the present invention includes:

[0381] The image recording method of the present invention described above is used to obtain an image recording article, which includes a non-permeable substrate and an image disposed on the non-permeable substrate; and

[0382] The process of laminating a laminating substrate onto the side of an image recorder containing the image to obtain a laminate.

[0383] The method for manufacturing the laminate of the present invention includes the image recording method of the present invention described above, and therefore achieves the same effect as the image recording method of the present invention described above. Specifically, a laminate with excellent boiling resistance can be obtained.

[0384] For the process of obtaining image recordings, please refer to the image recording method of the present invention.

[0385] The process of obtaining a laminate is to laminate a laminating substrate onto the side of an image recorder on which the image is disposed to obtain a laminate.

[0386] Lamination can be performed by methods such as: attaching a laminating substrate to the image-containing side of an image recorder via another layer (e.g., an adhesive layer); or attaching the image-containing side of the image recorder to the image-containing side of the laminating substrate using a laminator. In the latter case, a commercially available laminator can be used.

[0387] There is no particular limitation on the lamination temperature during lamination. For example, when attaching image recording material and laminating substrate via other layers (e.g., adhesive layers), a temperature of 20°C or higher is acceptable. Furthermore, when using a laminator, the temperature of the lamination rollers can be set within the range of 20°C to 80°C. The pressing force of the lamination roller pair can be selected appropriately as needed.

[0388] The substrate for lamination is preferably a resin substrate.

[0389] There are no particular limitations on the resin substrate; for example, a substrate made of thermoplastic resin can be cited.

[0390] Examples of resin substrates include substrates formed from thermoplastic resin in sheet form.

[0391] The resin substrate preferably contains polypropylene, polyethylene terephthalate, nylon, polyethylene or polyimide.

[0392] 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.

[0393] In the process of obtaining the laminate, the laminating substrate can be directly laminated onto the side of the image recorder where the image is located, or it can be laminated onto the side of the image recorder where the image is located via other layers (e.g., adhesive layers).

[0394] When a laminating substrate is directly laminated onto the side of an image recorder containing an image, lamination can be performed using known methods such as heat pressing or heat fusion.

[0395] Furthermore, the lamination of the laminating substrate onto the side of the image recorder where the image is disposed via an adhesive layer can be carried out, for example, by applying an adhesive to the side of the image recorder where the image is disposed, placing the laminating substrate, and then bonding the image recorder and the laminating substrate together.

[0396] Furthermore, lamination when the image is laminated on the side of the image recorder containing the image via an adhesive layer can also be implemented by methods such as compression lamination (i.e., sandwich lamination).

[0397] The adhesive layer preferably contains isocyanate. When the adhesive layer contains isocyanate, the adhesion between the adhesive layer and the image is further improved, thus further enhancing the resistance to boiling.

[0398] [Image Records]

[0399] The image recording device of the present invention comprises:

[0400] Non-permeable substrate and image disposed on non-permeable substrate,

[0401] The image contains:

[0402] A pretreatment layer, disposed on a non-permeable substrate, and containing a coagulant and a urethane resin, wherein the coagulant is at least one selected from the group consisting of organic acids, polyvalent metal compounds, and metal complexes; and

[0403] An ink layer, disposed on a pretreatment layer, contains pigments (e.g., at least one of white pigments and colored pigments) and urethane resins.

[0404] The urethane resin in the pretreatment layer comprises polyol units, polyisocyanate units, and polyalkylene glycol monoalkyl ether units.

[0405] The image recording object of the present invention can be manufactured by the image recording method of the present invention.

[0406] Therefore, it is possible to manufacture laminates with excellent boiling resistance.

[0407] Regarding the components in the pretreatment layer and the ink layer, one can appropriately refer to the components of the pretreatment liquid, the first ink, and the second ink.

[0408] The laminate of the present invention comprises:

[0409] The image recording device of the present invention described above; and

[0410] A laminating substrate, laminated onto the image of an image recorder.

[0411] The laminate of the present invention can be manufactured by the manufacturing method of the laminate of the present invention.

[0412] Therefore, it has excellent resistance to boiling.

[0413] The preferred method for the substrate used in lamination is as described above.

[0414] Example

[0415] The present invention will be described in more detail below through embodiments, but the present invention is not limited to the following embodiments as long as it does not depart from its spirit.

[0416] [Example 1]

[0417] <Preparation of an aqueous dispersion of urethane resin particles for pretreatment>

[0418] Add isophorone diisocyanate (IPDI) (14.4 g), DURANOL T5652 (manufactured by Asahi Kasei Corporation, polycarbonate diol; hereinafter also referred to as "T5652") (87.6 g) and ethyl acetate (80.0 g) to a three-necked flask, and heat to 70°C.

[0419] 0.1 g of NEOSTANN U-600 (manufactured by NITTOH CHEMICAL CO.,LTD., an inorganic bismuth catalyst; hereinafter also referred to as "U-600") was added and stirred at 70 °C for 3 hours.

[0420] Next, polyethylene glycol monomethyl ether (number average molecular weight 550) (18.0 g) was added and stirred at 70°C for 3 hours.

[0421] Next, isopropanol (IPA) (84.5 g) and ethyl acetate (126.5 g) were added as end-sealing materials, and the mixture was stirred at 70°C for 7 hours. After stirring for 7 hours, the mixture was allowed to cool naturally to room temperature, and then the concentration was adjusted using ethyl acetate to obtain a 30% by mass solution of carbamate A (solvent: a mixture of IPA and ethyl acetate).

[0422] Distilled water (100g) was added to a 30% by mass solution (100g) of the obtained carbamate A, and the mixture was emulsified at 12,000 rpm for 10 minutes at room temperature using a homogenizer to obtain an emulsion.

[0423] The obtained emulsion was heated to 50°C and stirred at 50°C for 5 hours, thereby removing ethyl acetate from the above liquid by distillation.

[0424] An aqueous dispersion of urethane resin particles (25% by mass) was obtained by diluting the liquid obtained by distillation to remove ethyl acetate with distilled water to make the solid content 25% by mass.

[0425] <Preparation of Pretreatment Solution>

[0426] A pretreatment solution with the following composition was prepared using an aqueous dispersion of the above-mentioned urethane resin particles and other components other than the urethane resin particles in the following ingredients.

[0427] -Composition of the pretreatment solution-

[0428] Ethanol…5% by mass

[0429] • urethane resin particles…10% by mass

[0430] • Coagulant……5% by mass

[0431] Surfactant (product name "OLFINE E1010", manufactured by Nissin Chemical Industry Co., Ltd.) ... 0.5% by mass

[0432] Water... is used to make the pretreatment solution a 100% by mass residue.

[0433] <Synthesis of Pigment Dispersion Resin 1>

[0434] Add 100g of dipropylene glycol to a three-necked flask equipped with a stirrer and a cooling tube, and heat to 85°C under a nitrogen atmosphere.

[0435] Prepared separately:

[0436] Solution 1 is composed of 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

[0437] Solution 2 was obtained by dissolving 1.0 g of tert-butyl peroxide-2-ethylhexanoate (product name "PERBUTYL O", manufactured by NOF CORPORATION) in 20 g of dipropylene glycol.

[0438] Solution 1 was added dropwise to the three-necked flask after 4 hours, and solution 2 was added dropwise after 5 hours.

[0439] After the addition was complete, the mixture was allowed to react for another 2 hours, then heated to 95°C and stirred for 3 hours to ensure all unreacted monomers reacted. The disappearance of monomers was determined using nuclear magnetic resonance (NMR). 1 Confirmed by ¹H-NMR.

[0440] The obtained reaction solution was heated to 70°C, and 12.0 g of dimethylethanolamine was added. Propylene glycol was then added and the mixture was stirred to obtain a 30% by mass solution of pigment dispersion resin 1.

[0441] pass 1 ¹H-NMR confirmed the structural units of the obtained pigment dispersion resin 1. Furthermore, the weight-average molecular weight (Mw) determined by GPC was 28,000.

[0442] Furthermore, the mass ratio of each structural unit in pigment dispersion resin 1 is: structural units derived from stearyl methacrylate / structural units derived from benzyl methacrylate / structural units derived from hydroxyethyl methacrylate / structural units derived from methacrylic acid = 14 / 35.3 / 20 / 30.7. Wherein, the above mass ratio does not include dimethylaminoethanol.

[0443] The acid value of pigment dispersion resin 1 is 200 mg KOH / g.

[0444] <Preparation of Pigment Dispersion 1>

[0445] Pigment dispersion 1 was prepared using a Ready mill model LSG-4U-08 (manufactured by Aimex CO.,LTD.).

[0446] 45 parts by mass of titanium dioxide particles (average primary particle size: 210 nm, trade name "PF-690", manufactured by Ishihara Sangyo Kaisha, Ltd.) as a white pigment, 15 parts by mass of a 30% by mass solution of the aforementioned pigment dispersion resin 1, and 40 parts by mass of ultrapure water were added to a zirconia container. Further, 40 parts by mass of 0.5 mm φ zirconia beads (manufactured by Toray Industries, Inc., Traceram beads) were added and lightly mixed with a spatula. The zirconia container containing the obtained mixture was placed in a ready mill and dispersed at 1000 rpm (revolutions per minute) for 5 hours. After dispersion, the mixture was filtered through a filter cloth to remove the beads, yielding a pigment dispersion 1 with a white pigment concentration of 45% by mass.

[0447] <Preparation of White Ink>

[0448] A white ink with the following composition was prepared using pigment dispersion 1 and the following components excluding pigment dispersion resin 1 and white pigment.

[0449] -Composition of white ink-

[0450] White pigment... 15% by weight

[0451] Pigment dispersion resin 1…1.5% by mass

[0452] ·1,2-Propanediol (PG)……20% by mass

[0453] Propylene glycol monomethyl ether (PGmME)……1% by mass

[0454] • Propylene glycol monopropyl ether (PGmPE)……1% by mass

[0455] Surfynol 104 (manufactured by Nissin Chemical Industry Co., Ltd.; acetylene glycol surfactant) ... 1% by mass

[0456] • BYK-345 (manufactured by BYK JAPAN KK; silicone surfactant)……1% by mass

[0457] • PVP K-15 (manufactured by Ashland Inc.; polyvinylpyrrolidone)……0.1% by mass

[0458] • SNOWTEX XS (manufactured by Nissan Chemical Corporation; colloidal silica) ... 0.05% by mass as solid component

[0459] ·PERMALIN UA-368 (SANYO CHEMICAL INDUSTRIES, LTD.; polycarbonate-based urethane resin emulsion)...as a solid component, it is 4% by mass.

[0460] Water... is used to make the total amount 100% by mass.

[0461] <Image Recording>

[0462] Image recording was performed using a pretreatment solution and white ink.

[0463] An inkjet recording device is prepared, comprising: a conveying system for continuously conveying a strip-shaped substrate; a bar coater for coating the substrate with a pretreatment liquid; and an inkjet head for applying ink.

[0464] Furthermore, as a substrate, a polyethylene terephthalate (PET) substrate (FUTAMURA CHEMICAL CO.,LTD. "FE2001" (thickness 12μm, width 780mm, length 4000m) was prepared as a non-permeable substrate; hereinafter referred to as "non-permeable substrate A").

[0465] The pretreatment solution was applied to a non-permeable substrate A using a wire rod coating machine to achieve a concentration of approximately 1.7 g / m². 2 Then it was dried at 50°C for 2 seconds.

[0466] Using an inkjet recording device, a non-permeable substrate A is continuously fed at 50 m / min, while white ink is ejected from the inkjet head onto a surface coated with a pretreatment liquid of the non-permeable substrate A to form a solid image. The applied white ink is dried with warm air at 80°C for 30 seconds, thereby recording a solid image and obtaining an image record.

[0467] -Ink application conditions-

[0468] Inkjet head: 1200dpi / 30inch wide piezoelectric full-line inkjet head

[0469] Ink ejection volume from the printhead: 3.0 pL (picoli)

[0470] Drive frequency: 41kHz (substrate conveying speed: 50m / min)

[0471] [evaluate]

[0472] The preservation stability of the pretreatment solution and the boiling resistance of the image recordings were evaluated.

[0473] The evaluation method is as follows.

[0474] The evaluation results are shown in Table 1.

[0475] (Storage stability of the pretreatment solution)

[0476] The viscosity of the pretreated solution after standing at 25°C for 1 hour (hereinafter referred to as "viscosity before storage") and the viscosity of the pretreated solution after storage at 60°C for 14 days under sealed conditions (hereinafter referred to as "viscosity after storage") were measured respectively.

[0477] Viscosities before and after storage were measured using a VISCOMETER TV-22 (manufactured by TOKI SANGYO CO.LTD) at 25°C and 100 rpm.

[0478] Here, the term "sealed state" refers to the state in which the contents are sealed inside the container, and specifically, the state in which the mass reduction of the contents is less than 1% by mass when stored at 50°C for 14 days.

[0479] The viscosity increase was calculated by subtracting the pre-storage viscosity from the post-storage viscosity.

[0480] The smaller the increase in viscosity, the better the storage stability.

[0481] The evaluation criteria are as follows.

[0482] -Evaluation criteria for the storage stability of pretreatment solutions-

[0483] 5: The viscosity increase is less than 0.3 mPa·s.

[0484] 4: The viscosity increase is greater than 0.3 mPa·s and less than 0.5 mPa·s.

[0485] 3: The viscosity increase is greater than 0.5 mPa·s and less than 1.0 mPa·s.

[0486] 2: The viscosity increase is greater than 1.0 mPa·s and less than 2.0 mPa·s.

[0487] 1: The viscosity increase is above 2.0 mPa·s.

[0488] (Boiling resistance of laminates)

[0489] Using a dry laminator (product name "FL2", manufactured by FUJI KIKAI KOGYO Co., Ltd.), a dry laminating adhesive (main agent TM-320 (isocyanate compound) / curing agent CAT-13B (alcohol compound); manufactured by Toyo-Morton, Ltd.) was coated onto a solid image of the aforementioned image recording. A linear low-density polyethylene film (trade name "LL-XMTN", manufactured by FUTAMURA CHEMICAL CO., LTD., 40 μm thick) was then layered on top as a laminating substrate. In this state, the laminating substrate and the image recording were bonded together to obtain a laminate.

[0490] The obtained laminate was aged at 40°C for 48 hours.

[0491] Two sample pieces, each 200mm long and 200mm wide, were cut from the aged laminate. The cut sample pieces were overlapped, and three sides were heat-sealed to obtain a bag. The bag was then filled with pure water and sealed by heat sealing.

[0492] The sealed bags were placed in a food sterilizer (small sterilizer) (product name "SR-240", manufactured by TOMY SEIKO CO.,LTD.) and boiled at 95°C for 40 minutes.

[0493] After boiling, the bags were removed and their condition was visually observed. Specifically, the boiling resistance was evaluated based on the bag's deformation and the presence or absence of lamination curling.

[0494] The evaluation criteria are as follows.

[0495] In addition, lamination peeling refers to the state in which the image or the substrate used for lamination peels off.

[0496] -Evaluation criteria for the boiling resistance of laminates-

[0497] 5: No deformation or lamination warping was confirmed.

[0498] 4: No lamination warping was observed, but deformation was confirmed.

[0499] 3: One instance of lamination warping was confirmed.

[0500] 2: Multiple laminates were found to be warped.

[0501] 1: Laminate warping was confirmed on the entire surface of the sample sheet.

[0502] (Examples 2-21, Comparative Examples 1-3)

[0503] As shown in Table 1, the type of coagulant in the pretreatment solution, the presence or absence of coagulant in the pretreatment solution, and at least one of the composition (structural unit) of the urethane resin particles were changed. Otherwise, the same operation as in Example 1 was performed.

[0504] The results are shown in Table 2.

[0505] Here, the types of units in the urethane resin particles and the types and contents of polyalkylene glycol monoalkyl ether units are changed by changing the composition of the monomers used in the manufacture of the urethane resin particles.

[0506] The molecular weight of urethane resin in urethane resin particles is changed by changing the reaction time.

[0507] The meanings of the abbreviations in Table 1 are as follows.

[0508] Acetic acid (Ca) ... calcium acetate

[0509] • Al sulfate … Aluminum sulfate

[0510] TC-310… Manufactured by Matsumoto Fine Chemical Co., Ltd. as “ORGATIX TC-310” (titanium lactate).

[0511] IPDI...Isophorone diisocyanate

[0512] HDI... hexamethylene diisocyanate

[0513] • PCD……Polycarbonate diol (trade name DURANOL T5652 (manufactured by Asahi Kasei Corporation), molecular weight 2000)

[0514] • PTMG… Polytetramethylene glycol (trade name PTMG 1000 (manufactured by Mitsubishi Chemical Corporation), molecular weight 1000)

[0515] • P-1100……A polyester polyol (trade name P-1100, manufactured by KURARAY CO.,LTD., molecular weight 1000) which is the product of the reaction of 3-methyl-1,5-pentanediol with adipic acid.

[0516] ·1,6-HDO……1,6-Hexanediol

[0517] ·PEGmME……Polyethylene glycol monomethyl ether

[0518] [Comparative Example 4]

[0519] The urethane resin particles in the pretreatment solution were replaced with acrylic resin particles, and otherwise the same operations as in Example 1 were performed.

[0520] The results are shown in Table 1.

[0521] The pretreatment solution of Comparative Example 4 was prepared using MOBINEIL 972 (manufactured by Japan Coating Resin CO.,LTD.) as an aqueous dispersion of acrylic resin particles.

[0522] [Comparative Example 5]

[0523] The same procedures as in Example 1 were performed to ensure that the pretreatment solution was free of urethane resin particles.

[0524] The results are shown in Table 1.

[0525] [Table 1]

[0526]

[0527] As shown in Table 1, in the examples using pretreatment solutions containing coagulants and urethane resins containing polyalkylene glycol monoalkyl ether units, the pretreatment solutions exhibited excellent storage stability, and the laminates exhibited excellent boiling resistance.

[0528] In contrast, in Comparative Example 1, where the urethane resin in the pretreatment solution did not contain polyalkylene glycol monoalkyl ether units, the storage stability of the pretreatment solution and the boiling resistance of the laminate decreased.

[0529] Comparative Examples 2 and 3, where the pretreatment solution did not contain coagulants.

[0530] Comparative Example 4 and 2, where the pretreatment solution contained acrylic resin but did not contain urethane resin.

[0531] In Comparative Example 5, the pretreatment solution did not contain urethane resin.

[0532] The boiling resistance of the laminates all decreased.

[0533] As can be seen from the results of Examples 1 to 8, when the weight-average molecular weight of the polyalkylene glycol monoalkyl ether unit is set as a and the weight-average molecular weight of the urethane resin is set as b, and the (a / b)×100 is 2.5 to 20.0 (Examples 2 to 6), the boiling resistance of the laminate is further improved.

[0534] The results of Examples 12-15 show that when the content of polyalkylene glycol monoalkyl ether units is 5% to 20% by mass relative to the total amount of urethane resin (Examples 13 and 14), the boiling resistance of the laminate is further improved.

[0535] The results of Examples 19-21 show that when the polyol unit in the urethane resin contains a polycarbonate diol unit (Example 19), the boiling resistance of the laminate is further improved.

[0536] The results of Examples 3 and 16-18 show that when the coagulant contains at least one selected from the group consisting of organic acid polymetallic salts and organic acids (Examples 3 and 16), the boiling resistance of the laminate is further improved.

[0537] As can be seen from the results of Examples 3 and 16, the boiling resistance of the laminate is further improved when the coagulant contains organic acids (Example 3).

[0538] [Example 101] (Evaluation of secondary color images)

[0539] <Preparation of Coloring Inks>

[0540] Coloring inks with the compositions shown in Table 2 were prepared (specifically, cyan ink, magenta ink, yellow ink, and black ink).

[0541] [Table 2]

[0542] APD4000C (Solid Components) 3 APD4000M (Solid Components) 4 APD1000R (Solid Components) 2 APD4000Y (Solid Component) 4 APD4000K (Solid Components) 4 PG 25 25 25 25 PGmME 3 3 3 3 PGmPE 1 1 1 1 Surfynol 104 1 1 1 1 BYK-345 1 1 1 1 PVP K-15 0.1 0.1 0.1 0.1 SNOWTEX XS 0.05 0.05 0.05 0.05 PERMALIN UA-368 6 3 3 3 water Remaining amount Remaining amount Remaining amount Remaining amount

[0543] In Table 2, the numerical values ​​of each component represent its content (mass%) in the corresponding ink, and the "remaining amount" as the amount of water represents the remaining amount used to make the total 100% by mass.

[0544] In Table 2, the detailed information of the components below PG (1,2-propanediol) is the same as that of the white ink mentioned above.

[0545] APD4000C and other pigment dispersions in Table 2 are detailed below.

[0546] Table 2 shows the amount of solid components (total amount of pigment and pigment dispersant) as the amount of pigment dispersion.

[0547] • APD4000C……Projet Cyan APD4000 (manufactured by FUJIFILM Imaging Colorants, Inc., cyan pigment dispersion, pigment concentration: 20% by mass)

[0548] • APD4000M……Projet Magenta APD4000 (manufactured by FUJIFILM Imaging Colorants, Inc., magenta pigment dispersion, pigment concentration: 20% by mass)

[0549] • APD1000R……Projet Red APD1000 (manufactured by FUJIFILM Imaging Colorants, Inc., red pigment dispersion, pigment concentration: 16% by mass)

[0550] • APD4000Y……Projet Yellow APD4000 (manufactured by FUJIFILM Imaging Colorants, Inc., yellow pigment dispersion, pigment concentration: 20% by mass)

[0551] • APD4000K……Projet Black APD4000 (manufactured by FUJIFILM Imaging Colorants, Inc., black pigment dispersion, pigment concentration: 15% by mass)

[0552] <Image Recording>

[0553] Using the pretreatment solution from any of Examples 1-21 and Comparative Examples 1-5,

[0554] White ink in Example 1

[0555] The coloring inks shown in Table 2 above (specifically, cyan ink, magenta ink, yellow ink, and black ink)

[0556] Image recording was performed.

[0557] In detail, each of the following image records A to D is performed to obtain a solid image.

[0558] In the image recordings A to D below, the conditions for applying the pretreatment liquid, the drying conditions after applying the pretreatment liquid, the ink application conditions, and the drying conditions after applying the ink are set to the same conditions as those for the image recordings in Example 1.

[0559] Image recording A... sequentially applies pretreatment solution, dries, applies cyan ink, applies white ink, and dries the image.

[0560] Image recording B... sequentially applies pretreatment solution, dries, applies cyan ink, applies magenta ink, applies yellow ink, applies black ink, applies white ink, and dries the image.

[0561] Image recording C... sequentially performs image recording by applying pretreatment solution, drying, applying cyan ink, drying, applying white ink, and drying.

[0562] Image recording D... sequentially applies pretreatment solution, dries, applies cyan ink, applies magenta ink, applies yellow ink, applies black ink, dries, applies white ink, and dries the image.

[0563] Using the image records obtained in Image Records A to D, the laminate was fabricated and the boiling resistance of the laminate was evaluated in the same manner as in Example 1.

[0564] The results confirmed that, when using the pretreatment solutions in Examples 1 to 21, regardless of which of the image recordings A to D was performed, the laminate exhibited excellent boiling resistance, just like in Examples 1 to 21 (i.e., monochrome image recording with white ink).

[0565] The invention of Japanese Patent Application No. 2022-020630, filed on February 14, 2022, is incorporated herein by reference in its entirety.

[0566] All documents, patent applications and technical standards described in this specification are incorporated herein by reference to the same extent as the specific documents, patent applications and technical standards which are incorporated herein by reference.

Claims

1. A pretreatment solution for inkjet ink, comprising: The coagulant is at least one selected from the group consisting of organic acids, polyvalent metal compounds, and metal complexes; water; and urethane resin. The urethane resin comprises polyol units, polyisocyanate units, and polyalkylene glycol monoalkyl ether units. When the number-average molecular weight of the polyalkylene glycol monoalkyl ether used to form the polyalkylene glycol monoalkyl ether unit is set as a, and the number-average molecular weight of the urethane resin is set as b, (a / b)×100 is 2.5 to 16.

0.

2. The pretreatment solution for inkjet ink according to claim 1, wherein, The content of the polyalkylene glycol monoalkyl ether unit is 5% to 20% by mass relative to the total amount of the urethane resin.

3. The pretreatment solution for inkjet ink according to claim 1, wherein, The polyol unit includes a polycarbonate diol unit.

4. The pretreatment solution for inkjet ink according to claim 1, wherein, The coagulant contains at least one selected from the group consisting of the organic acid and organic acid polyvalent metal salts that are the polyvalent metal compounds.

5. The pretreatment solution for inkjet inks according to any one of claims 1 to 4, wherein, The coagulant contains the organic acid.

6. The pretreatment solution for inkjet inks according to any one of claims 1 to 4, wherein, The (a / b)×100 is 2.5 to 15.

6.

7. An ink group comprising: Pretreatment solution for inkjet inks according to any one of claims 1 to 6; and The first ink is an inkjet ink containing water and urethane resin.

8. The ink group according to claim 7, wherein, The first ink also contains white pigment.

9. The ink group according to claim 8, wherein, The ink group also contains a second ink, which is an inkjet ink containing water, coloring pigments and urethane resin.

10. An image recording method using the ink set of claim 7 or 8, the image recording method comprising: The process of applying the pretreatment solution for inkjet ink to a non-permeable substrate; and The process of applying the first ink to the non-permeable substrate on which the inkjet ink pretreatment solution has been applied by inkjet recording.

11. An image recording method using the ink set of claim 9, the image recording method comprising: The process of applying the pretreatment solution for inkjet ink to a non-permeable substrate; and The process of applying the first ink and the second ink to the non-permeable substrate, which has been treated with the inkjet ink pretreatment solution, by means of inkjet recording.

12. A method for manufacturing a laminate, comprising: The process of obtaining an image recording article by the image recording method according to claim 10 or 11, wherein the image recording article comprises the non-permeable substrate and an image disposed on the non-permeable substrate; and The process of laminating a laminating substrate onto the side of the image recorder where the image is disposed to obtain a laminate.

13. An image recording article comprising a non-permeable substrate and an image disposed on the non-permeable substrate, the image comprising: A pretreatment layer is disposed on the non-permeable substrate and contains a coagulant and a urethane resin, wherein the coagulant is at least one selected from the group consisting of organic acids, polyvalent metal compounds and metal complexes; and An ink layer, disposed on the pretreatment layer, contains pigments and urethane resin. The urethane resin in the pretreatment layer comprises polyol units, polyisocyanate units, and polyalkylene glycol monoalkyl ether units. When the number-average molecular weight of the polyalkylene glycol monoalkyl ether used to form the polyalkylene glycol monoalkyl ether unit is set as a, and the number-average molecular weight of the urethane resin is set as b, (a / b)×100 is 2.5 to 16.

0.

14. The image recording article according to claim 13, wherein, The (a / b)×100 is 2.5 to 15.

6.

15. A laminate comprising: The image recording as described in claim 13 or 14; and A laminating substrate is laminated onto the image of the image recorder.

Images