Liquid ink composition, printed material, laminate or packaging

Abstract

The present disclosure provides a liquid ink composition which is capable of forming an ink layer that is excellent in terms of adhesion, blocking resistance and peel strength. The present disclosure specifically provides a liquid ink composition which contains at least a urethane resin component and an organic solvent, wherein: the urethane resin component contains at least a urethane resin (I) that uses, as a reaction starting material (1), a polycarbonate or a polyoxyalkylene compound that has a constituent unit having 3 to 4 carbon atoms, and a first isocyanate compound; and the urethane bond concentration of the entire urethane resin component is 0.98 mmol / g or more.

Description

[Technical Field]

[0001] This disclosure relates to liquid ink compositions, printed materials, laminates, or packaging. [Background technology]

[0002] Gravure inks or flexographic inks are widely used to impart aesthetic appeal and functionality to substrates. When these substrates are used as packaging materials, particularly food packaging, lamination is commonly applied. In this case, depending on the type of contents or intended use, various substrates and lamination processes are utilized, such as front-side printing (printing from the front of the material, such as plastic film) or back-side printing (reversing the orientation of the printed image or the order of the colors). Traditionally, polyurethane resin and vinyl chloride-vinyl acetate copolymer resin have been widely used as binder resins in inks for this type of lamination process, as they offer both excellent dispersibility and high film properties. This combination of polyurethane resin and vinyl chloride-vinyl acetate copolymer resin is an indispensable ink raw material for achieving good printability and the various physical properties required for laminating inks (adhesion to substrate, lamination strength, and boil-retort suitability). For example, Patent Document 1 discloses a laminate ink composition for flexible packaging, which mainly comprises a colorant, an organic solvent other than an aromatic organic solvent, and a binder resin that includes a polypropylene glycol-containing polyurethane resin and a vinyl chloride vinyl acetate copolymer resin having hydroxyl groups as essential components.

[0003] However, in response to the trend towards building a circular economy that reduces substances that can have adverse effects on human health or the environment, as exemplified by the Sustainable Development Goals, legal regulations surrounding food packaging materials are becoming stricter worldwide. In particular, in recent years, there has been a demand for stricter regulations on the components used in packaging and their migration into food. Furthermore, the movement to reduce plastic use is accelerating, and the demand for recyclable packaging is increasing. Therefore, in the development of gravure ink products, it has become necessary to design inks and packaging components using materials that ensure safety for human health and the environment. In particular, vinyl chloride-vinyl acetate copolymer is a substance of concern as it hinders packaging recycling for the following reasons (a) and (b). (a) Chlorine-based resins such as polyvinyl chloride can cause corrosion of equipment or piping due to the release of hydrogen chloride and the generation of hydrochloric acid during the thermal decomposition process of recycling. (b) In thermal recycling, which reuses energy generated when waste is incinerated, incinerating chlorine-based resins may release endocrine disruptors such as dioxins. Therefore, the development of environmentally friendly inks, such as chlorine-free inks that do not contain chlorine-based resins, will be required in the future. For example, Patent Document 2 discloses a technology for an organic solvent-based gravure ink containing a pigment, an organic solvent, and a binder resin having a chlorine content of 5% by mass or less and containing urethane resin (A) and resin (B). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-096163 [Patent Document 2] Japanese Patent Publication No. 2022-139294 [Overview of the project] [Problems that the invention aims to solve]

[0005] Patent documents 1 and 2 mentioned above have examined blocking resistance, film adhesion, and lamination characteristics. However, they do not address the problem that if the printed surface, which displays information about the contents or patterns that evoke aesthetic appeal, is damaged, the information or patterns will be lost. Therefore, the present disclosure aims to provide a liquid ink composition that can form an ink layer with an excellent balance of blocking resistance, adhesion, lamination suitability, scratch resistance, pigment dispersibility, fluidity, and storage (over time) stability. [Means for solving the problem]

[0006] Therefore, the present inventors diligently studied to solve the above problems and found that by using a predetermined urethane resin (I) and controlling the urethane bond concentration, it is possible to form an ink layer with an excellent balance of blocking resistance, adhesion, lamination suitability, scratch resistance, pigment dispersibility, fluidity, and storage (over time) stability, and thus completed the present invention as described in any of (1) to (13) below.

[0007] [1] The present disclosure relates to a liquid ink composition comprising at least a urethane resin component and an organic solvent, wherein the urethane resin component comprises at least a urethane resin (I) reacted with polycarbonate or a polyoxyalkylene compound having 3 to 4 carbon atoms as a structural unit and a first isocyanate compound as a reaction raw material (1), and the total urethane bond concentration of the urethane resin component is 0.98 mmol / g or more.

[0008] [2] The liquid ink composition according to [1], wherein the content of vinyl chloride vinyl acetate copolymer resin having hydroxyl groups (solid content) is less than 4.5% by mass of the total liquid ink composition (solid content).

[0009] [3] The liquid ink composition according to [1] or [2], comprising at least a binder resin containing the urethane resin component and the organic solvent, wherein the chlorine content of the binder resin is 5% by mass or less.

[0010] [4] A liquid ink composition comprising at least a binder resin containing the urethane resin component and the organic solvent, The liquid ink composition according to any one of [1] to [3] above, wherein the proportion of the total solid content of the urethane resin component to the total solid content of the binder resin component is 50% by mass or more.

[0011] [5] The liquid ink composition according to any one of [1] to [4] above, wherein the urethane resin (I) is a urethane urea resin.

[0012] [6] The liquid ink composition according to any one of [1] to [5] above, wherein the urethane bond concentration of the urethane resin (I) is 0.98 mmol / g or more.

[0013] [7] A liquid ink composition according to any one of [1] to [6] above, comprising a urethane resin (II) other than the urethane resin (I).

[0014] [8] The liquid ink composition according to [7] above, wherein the urethane bond concentration of at least one of the urethane resin (I) or the urethane resin (II) is 0.98 mmol / g or more.

[0015] [9] The liquid ink composition according to [7] or [8] above, wherein the total amount of urethane resin (I) and urethane resin (II) among the resin components contained in the liquid ink composition is 30 to 100% by mass with respect to the total resin solids of the liquid ink composition.

[0016]

[10] A liquid ink composition according to any one of [1] to [9] above, comprising at least one resin selected from polyvinyl butyral resin, maleic acid resin, cellulose resin, polyester resin, acrylic resin, and polyamide resin.

[0017]

[11] Further containing a pigment, wherein the amount of base adsorption per unit surface area of ​​the pigment is 0.30 μmol / m². 2 The liquid ink composition described in any of the above [1] to

[10] .

[0018]

[12] A liquid ink composition according to any one of [1] to

[11] above, further comprising a pigment, wherein the pigment contains 200 ppm or more of iron element per 100 parts by mass of pigment.

[0019]

[13] A printed article obtained by printing any of the ink compositions described in [1] to

[12] above onto a substrate. [Effects of the Invention]

[0020] According to this disclosure, it is possible to provide a liquid ink composition that can form an ink layer with an excellent balance of blocking resistance, adhesion, lamination suitability, scratch resistance, pigment dispersibility, and fluidity and storage (over time) stability. [Modes for carrying out the invention]

[0021] The embodiments of the present invention (hereinafter referred to as "these embodiments") will be described in detail below, but the present invention is not limited to the following description and can be implemented in various ways within the scope of its gist. Furthermore, in these embodiments, A (numerical value) to B (numerical value) means A or greater and B or less.

[0022] [Definition] In this specification, "liquid ink composition" refers to a liquid printing ink applied to a printing method using a printing plate, such as gravure ink or flexographic ink, and is preferably gravure ink or flexographic ink. Furthermore, in the following explanation, "ink" always refers to "printing ink." In this specification, "parts" always refers to "parts by mass," "total ink" refers to the total amount of ink including all volatile components such as solvents, and "(ink or resin) solids (total)" refers to the total amount of non-volatile components only, excluding volatile components. In this specification, "reaction material" refers to a compound used to obtain a target compound by a chemical reaction such as combination or decomposition, and which partially constitutes the chemical structure of the target compound, excluding catalysts and solvents. In particular, in this specification, "reaction material" refers to a precursor for obtaining the target urethane resin (I) or urethane resin (II) by a chemical reaction, and includes various isocyanate compounds, various polyols, and amine compounds added as needed (for example, amine compounds such as chain extenders described later). For example, "content of the first isocyanate compound in reaction material (1) (100% by mass)" represents the ratio of the first isocyanate compound to 100% by mass of the total amount of all polyol components (the total amount of polycarbonate or polyoxyalkylene compounds having 3 to 4 carbon atoms, optionally blended polyester polyols, optionally blended aromatic polyols, optionally blended polyether polyols, and optionally blended polyols used in combination) In this specification, "constituent unit" refers to a (repeating) unit of a chemical structure formed during a reaction or polymerization. In other words, in a compound formed by a reaction or polymerization, it refers to a substructure other than the chemical bond structure involved in the reaction or polymerization, and is commonly known as a residue.

[0023] In this specification, the "aromatic group" may be substituted or unsubstituted. The "aromatic group" preferably has an aromatic ring with 3 to 30 carbon atoms, and more preferably has an aromatic ring with 4 to 26 carbon atoms, excluding the number of carbon atoms of the substituent. Furthermore, in this specification, the hydrogen atoms of the aromatic ring in the "aromatic group" may be substituted with substituents, such as alkyl groups with 1 to 10 carbon atoms, alkoxy groups with 1 to 10 carbon atoms, or halogen atoms. The "aromatic group" may also include heteroaromatic groups, and the -CH2- or -CH= atoms in the "aromatic group" may be substituted with -O-, -S-, or -N= such that they are not adjacent to each other. Examples of the types of aromatic rings include monocyclic aromatic rings, fused aromatic rings, or ring-aggregated aromatic rings. Examples of the monocyclic aromatic rings include benzene, furan, pyrrole, thiophene, imidazole, pyrazole, oxazole, isoxazole, thiazole, isothiazole, pyridine, pyrimidine, pyridazine, pyrazine, and triazine. Examples of the fused aromatic rings include naphthalene, anthracene, phenalene, phenanthrene, quinoline, isoquinoline, quinazoline, phthalazine, pteridine, coumarin, indole, benzimidazole, benzofuran, and acridine. Examples of the ring-aggregated aromatic rings include biphenyl, binaphthalene, bipyridine, bithiophene, phenylpyridine, phenylthiophene, terphenyl, diphenylthiophene, and quaterphenyl. Furthermore, the hydrogen atoms of the aromatic ring in the aromatic group may be substituted with, for example, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or a halogen atom. Note that a divalent aromatic group refers to an aromatic group from which two hydrogen atoms have been removed. In this specification, "aryl group" refers to, for example, a phenyl group, naphthyl group, phenalenyl group, phenantrenyl group, anthryl group, azlenyl group, indenyl group, indanyl group, tetralinyl group, etc. Furthermore, the hydrogen atoms of the aromatic ring in the "aryl group" may be substituted with, for example, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, or a halogen atom. The "arylene group" refers to a divalent group obtained by removing one arbitrary hydrogen atom from the "aryl group" mentioned above. Examples of "aralkyl groups" as used herein include benzyl groups, diphenylmethyl groups, biphenyl groups, naphthylmethyl groups, and the like. The hydrogen atoms of the aromatic ring in the aralkyl group may be substituted with, for example, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or a halogen atom. An "aralkylene group" is a divalent group obtained by removing one arbitrary hydrogen atom from the "aralkyl group." In this specification, "aryloxy group" refers to a phenoxy group, naphthyloxy group, anthuryloxy group, phenanthryloxy group, or pyrenyloxy group, etc. The hydrogen atoms of the aromatic ring in the aryloxy group may be substituted with, for example, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, or a halogen atom. In this specification, "arylthio group" refers to arylthio groups such as phenylthio group, naphthylthio group, anthrylthio group, phenanthrylthio group, or pyrenylthio group. The hydrogen atoms of the aromatic ring in the arylthio group may be substituted with, for example, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, or a halogen atom. In this specification, "alkyl group" may be linear, branched, or cyclic, and examples include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, tert-pentyl group, neopentyl group, 1,2-dimethylpropyl group, n-hexyl group, isohexyl group, (n-)heptyl group, (n-)octyl group, (n-)nonyl group, (n-)decyl group, (n-)undecyl group, (n-)dodecyl group, or cycloalkyl groups as described below. An "alkylene group" is a group obtained by removing one hydrogen atom at any position from the above alkyl group, and examples include methylene group, ethylene group, propylene group, isopropylene group, n-butylene group, isobutylene group, sec-butylene group, tert-butylene group, n-pentylene group, isopentylene group, tert-pentylene group, neopentylene group, 1,2-dimethylpropylene group, n-hexylene group, isohexylene group, (n-)heptylene group, (n-)octylene group, (n-)nonylene group, (n-)decylene group, (n-)undecylene group, (n-)dodecylene group, or the cycloalkylene group described below. In this specification, "cycloalkyl group" refers to a cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group, cyclodecyl group, norbornyl group, or adamantyl group. "Cycloalkylene group" refers to a group obtained by removing one hydrogen atom at any position from the cycloalkyl group, such as a cyclopropylene group, cyclobutylene group, cyclopentylene group, cyclohexylene group, cycloheptylene group, cyclooctylene group, cyclononylene group, cyclodecylene group, norbornylene group, or adamantylene group. The hydrogen atoms of the cycloalkyl group or the cyclic group in the cycloalkylene group may be substituted with, for example, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, or a halogen atom. In this specification, "alkylthio group" refers to a methylthio group, an ethylthio group, a propylthio group, a butylthio group, an octylthio group, or a 2-ethylhexylthio group. In this specification, "alkenyl group" refers to groups such as ethynyl, 1-propynyl, 2-propynyl, 2-butynyl, pentynyl, hexynyl, vinyl, allyl, or isopropenyl. "Alkenylene group" is a group obtained by removing one hydrogen atom from the aforementioned alkenyl group. In this specification, "alkoxy group" refers to, for example, a methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, pentyloxy group, hexyloxy group, 2-ethylhexyloxy group, octyloxy group, or nonyloxy group. "Alkylene oxide group" refers to, for example, divalent groups such as ethylene oxide group, propylene oxide group, butylene oxide group, and pentylene oxide group. In this specification, "halogen atom" refers to, for example, a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom. An "organic group" is a group having 1 to 20 carbon atoms. Therefore, the above-mentioned "aromatic group," "aryl group," "arylene group," "aralkyl group," "aralkylene group," "aryloxy group," "arylthio group," "alkyl group," "cycloalkyl group," "alkylthio group," "alkenyl group," "alkenylene group," "alkoxy group," and "alkylene oxide group" are all included in the category of "organic groups." Furthermore, any hydrogen atom can be removed according to the valency. For example, a trivalent alkyl group is a group obtained by removing two arbitrary hydrogen atoms from an alkyl group.

[0024] [Liquid ink composition (hereinafter also simply referred to as ink composition)] The liquid ink composition of this disclosure contains at least a urethane resin component and an organic solvent. The urethane resin component contains at least a urethane resin (I). The urethane resin (I) is a compound that uses polycarbonate or a polyoxyalkylene compound having 3 to 4 carbon atoms as a reaction raw material (1) and a first isocyanate compound. Furthermore, the total urethane bond concentration of the urethane resin component is 0.98 mmol / g or higher. This makes it possible to provide an ink composition with excellent blocking resistance, adhesion, suitability for boil-lamination, scratch resistance, pigment dispersibility, fluidity, and storage (over time) stability. The liquid ink composition of this embodiment, when described in terms of morphological classification, contains a binder resin, an organic solvent, and one or more components selected from the group consisting of pigments and additives, which are added as needed. The binder resin contains a urethane resin component as an essential component, and the urethane resin component contains at least a urethane resin (I) in which polycarbonate or a polyoxyalkylene compound having 3 to 4 carbon atoms as a structural unit and a first isocyanate compound as reaction raw materials (1). In this specification, "urethane resin component" is a general term for resins having a number average molecular weight of 1000 or more and containing urethane bonds, and at least contains urethane resin (I). The "urethane resin component" may further contain urethane resin (II) other than urethane resin (I) as needed. In other words, urethane resin (II) other than urethane resin (I) means having a different chemical structure from urethane resin (I). In this specification, "binder resin" refers to a binding resin contained in an ink or ink composition. The binder resin may be dissolved in a solvent or in an emulsion state. Therefore, the binder resin must contain a urethane resin component, and may also contain other binder resins (hereinafter referred to as "other resins") as needed. For the sake of clarity, "polyester polyol" and "polyether polyol," which may be included as components of reaction raw material (2) for urethane resin (II), are referred to as "polyester polyol (II)" and "polyether polyol (II)." Similarly, "isocyanate compound," which is a component of reaction raw material (2) for urethane resin (II), is referred to as the "second isocyanate compound," and "isocyanate compound," which is a component of reaction raw material (1), is referred to as the "first isocyanate compound."

[0025] In the liquid ink composition of this embodiment, the content of the urethane resin component (solids) is preferably 5 to 95% by mass, more preferably 15 to 80% by mass, even more preferably 20 to 60% by mass, and even more preferably 30 to 60% by mass, based on the total solids of the liquid ink composition. By setting the content of the urethane resin component (solids) to 30% by mass or more, better polyethylene extrusion lamination strength is achieved when printed on OPP film.

[0026] In the liquid ink composition of this embodiment, the content of binder resin (solids) is preferably 5 to 95% by mass, more preferably 15 to 80% by mass, and even more preferably 20 to 65% by mass, based on the total solids of the liquid ink composition. By setting the binder resin (solids) content to 20% by mass or more, better pigment dispersion stability or coating film properties are exhibited. On the other hand, by setting the binder resin (solids) content to less than 20% by mass, print color density is exhibited.

[0027] In the liquid ink composition of this embodiment, the proportion of the urethane resin component (solids) to the total solids of the binder resin (solids) is preferably 30 to 100% by mass, more preferably 40 to 90% by mass, and even more preferably 50 to 80% by mass. By setting the proportion of the urethane resin component (solids) to 50% by mass or more, better polyethylene extrusion lamination strength is achieved when printed on OPP film.

[0028] The liquid ink composition of this embodiment may further contain a urethane resin (II) other than the urethane resin (I) as needed. This allows for the formation of an ink layer with superior blocking resistance, adhesion, lamination suitability, scratch resistance, pigment dispersibility, and fluidity and storage (over time) stability.

[0029] Furthermore, the liquid ink composition of this embodiment may optionally contain binder resins other than urethane resin components (other resins). This allows for the formation of an ink layer with superior blocking resistance, adhesion, lamination suitability, scratch resistance, pigment dispersibility, fluidity, and storage (over time) stability. The liquid ink composition of this embodiment may further contain, if necessary, one or more selected from the group consisting of pigments and additives.

[0030] The following describes in detail the essential components of the liquid ink composition of this disclosure: urethane resin component, urethane resin (I), and organic solvent, as well as the optional components: urethane resin (II), other resins that are binder resins other than the urethane resin component, pigments, and additives.

[0031] (Urethane resin component) The liquid ink composition of this disclosure contains a urethane resin component which is a resin having a number average molecular weight of 1000 or more and having urethane bonds, and the urethane resin component essentially contains urethane resin (I). The urethane resin component has the function of improving the adhesion of the ink as a binder resin and can also function as a pigment dispersion resin. The urethane resin component may contain urethane resin (II) other than urethane resin (I). By using a predetermined urethane resin (I) in combination with urethane resin (II) other than urethane resin (I), an ink layer with superior blocking resistance, adhesion, lamination suitability, scratch resistance, pigment dispersibility, fluidity, and storage (over time) stability can be formed.

[0032] <Urethane binding concentration> The lower limit of the total urethane bonding concentration of the urethane resin component in this embodiment is 0.98 mmol / g or more, more preferably 1.05 mmol / g or more, even more preferably 1.10 mmol / g or more, even more preferably 1.15 mmol / g or more, and particularly preferably 1.20 mmol / g or more. On the other hand, the upper limit of the total urethane bonding concentration of the urethane resin component is 5.0 mmol / g or less, more preferably 4.0 mmol / g or less, even more preferably 3.0 mmol / g or less, even more preferably 2.0 mmol / g or less, and particularly preferably 1.5 mmol / g or less. Furthermore, when a relatively low molecular weight isocyanate raw material such as tolylene diisocyanate is used as the reaction raw material for urethane resin (I), the upper limit of the urethane bond concentration of the entire urethane resin component is 5.0 mmol / g or less, more preferably 4.0 mmol / g or less, even more preferably 3.0 mmol / g or less, even more preferably 2.3 mmol / g or less, and particularly preferably 1.8 mmol / g or less. The preferred ranges for the total urethane bonding concentration of the urethane resin component in this embodiment include 0.98 mmol / g to 5.0 mmol / g, 1.05 mmol / g to 4.0 mmol / g, 1.10 mmol / g to 3.0 mmol / g, or 1.10 mmol / g to 2.0 mmol / g. The upper and lower limits can be combined in any way. A urethane bonding concentration of 0.98 mmol / g or higher is preferable from the viewpoint of polyethylene extrusion lamination strength when printed on OPP film. On the other hand, a urethane bonding concentration of 2.0 mmol / g or lower is preferable from the viewpoint of urethane resin raw material cost, ink viscosity, and flexibility of the ink coating on the film (following film deformation).

[0033] In this specification, the urethane bond concentration is calculated using the following formula (a). More specifically, the method for calculating the urethane bond concentration will be explained below, taking as an example the case in which the urethane resin component of this embodiment includes urethane resin (I), urethane resin (II)...urethane resin (k) (where k is a natural number), that is, the case in which the urethane resin component is composed of k types of urethane resin. At that time, it is assumed that the polyol component (including at least a polycarbonate or a polyoxyalkylene compound having a structural unit with 3 to 4 carbon atoms) contained in the reaction raw material (1) of the urethane resin (I) is w types (w is a natural number), and the polyol component (including at least one of a polyester polyol or a polyether polyol) contained in the reaction raw material (2) of the urethane resin (II) is v types (v is a natural number), ······ and the polyol component (including at least a polyester polyol or a polyether polyol) contained in the reaction raw material (k) of the urethane resin (k) is x types (x is a natural number). [Formula (a)]: Formula (a): Urethane bond concentration = [{(W i1 ×OH<000000�>+W i2 ×OH i2 +···W iw ×OH iw )+(W ii1 ×OH ii1 +W ii2 ×OH<( ii2 +···W iiv ×OH iiv )+···+(W k1 ×OH k1 +W k2 ×OH k2 +···W kx ×OH kx )}×1000] / (56100×S) "In the above formula (a); " W " i1 : The mass of the first polyol component contained in the reaction raw material (1) of the urethane resin (I) OH<00000二十一>: The hydroxyl value of the first polyol component contained in the reaction raw material (1) of the urethane resin (I) W<00000二十二>: The mass of the second polyol component contained in the reaction raw material (1) OH<00000二十三>: The hydroxyl value of the second polyol component contained in the reaction raw material (1) W<00000二十四>: The mass of the w-th polyol component contained in the reaction raw material (1) OH<00000二十五>:Hydrogen value of polyol component w contained in the reaction raw material (1) W ii1 : Mass of the first polyol component contained in the reaction raw material (2) of urethane resin (II) OH ii1 :Hydroxyl value of the first polyol component contained in the reaction raw material (2) of urethane resin (II) W ii2 : Mass of the second polyol component contained in the reaction raw material (2) OH ii2 :Hydroxyl value of the second polyol component contained in the reaction raw material (2) W iiv : Mass of the v-th polyol component contained in the reaction raw material (2) OH iiv :Hydrogen value of the v-th polyol component contained in the reaction raw material (2) W k1 : Mass of the first polyol component contained in the reaction raw material (k) of urethane resin (k) OH k1 : Hydroxyl value of the first polyol component contained in the reaction raw material (k) of urethane resin (k) W k2 : Mass of the second polyol component contained in the reaction raw material (k) OH k2 :Hydroxyl value of the second polyol component contained in the reaction raw material (k) W kx : Mass of the xth polyol component contained in the reaction raw material (k) OH kx :Hydrogen value of the xth polyol component contained in the reaction raw material (k) S: Mass of the total solid content of the urethane resin component. In formula (a) above, when the urethane resin component is composed of one or more urethane resins, and one or more polyol components are used as reaction raw materials for each of the one or more urethane resins, the calculation is performed using polyol components (i1) to (iw), polyol components (ii1) to (iiv), ..., polyol components (k1) to (kx) respectively. That is, in formula (a) above, for all polyol components constituting the urethane resin component, the urethane bond concentration is calculated by multiplying the sum of the products of the mass of each polyol component in the total polyol component and the hydroxyl value of that polyol component by 1000 as the numerator, and multiplying the value by 56100 by the mass of the total solid content of the urethane resin component as the denominator. Furthermore, the urethane bond concentration in this specification can be measured as follows. A urethane resin is obtained by solvent extraction from the liquid ink composition of this embodiment. The urethane bond concentration can then be calculated by performing the following two analytical methods on a sample of the solvent-extracted urethane resin. Analytical method 1: Perform NMR analysis and calculate the urethane bond concentration from the integral value of the peak originating from the urethane bond. Analytical Method 2: By performing NMR, GPC, and mass spectrometry, information on the molecular weight, chemical structure, and content ratio of isocyanate compounds, polyol components, and amine compounds that constitute the urethane resin is obtained. The urethane bond concentration is calculated from this compositional information. Furthermore, it is preferable that the urethane resin component as a whole in this embodiment contains polyester polyol as a reaction material. Specifically, either urethane resin (I) or urethane resin (II) may contain polyester polyol as a reaction material, or both urethane resin (I) and urethane resin (II) may contain polyester polyol as a reaction material. Similarly, it is preferable that the urethane resin component as a whole in this embodiment contains polyether polyol as a reaction material. Specifically, either urethane resin (I) or urethane resin (II) may contain polyether polyol as a reaction material, or both urethane resin (I) and urethane resin (II) may contain polyether polyol as a reaction material.

[0034] (Urethane resin (I)) The liquid ink composition of this embodiment contains, as an essential component, at least a urethane resin (I) which is reacted with polycarbonate or a polyoxyalkylene compound having 3 to 4 carbon atoms as a reaction raw material (1) and a first isocyanate compound. In other words, the urethane resin (I) in this embodiment has a structure in which a structural unit derived from polycarbonate or a polyoxyalkylene compound having 3 to 4 carbon atoms is directly or indirectly chemically bonded to a structural unit derived from the first isocyanate compound. Furthermore, the reaction raw material (1) may further contain a polyester polyol and / or an aromatic polyol, as described later. That is, the liquid ink composition of this embodiment may contain a urethane resin (I) in which the reaction raw material (1) is a polycarbonate or a polyoxyalkylene compound having 3 to 4 carbon atoms, a polyester polyol, an aromatic polyol, and a first isocyanate compound. In other words, one of the preferred urethane resins (I) in this embodiment has a structure in which a structural unit derived from a polycarbonate or a polyoxyalkylene compound having 3 to 4 carbon atoms, a structural unit derived from a polyester polyol, a structural unit derived from an aromatic polyol, and a structural unit derived from a first isocyanate compound are directly or indirectly chemically bonded. The urethane resin (I) is not particularly limited as long as it is a resin having urethane bonds obtained by reacting a polyol with an isocyanate. Furthermore, the urethane resin (I) has the function of improving ink adhesion as a binder resin and can also function as a pigment dispersion resin. Moreover, it is preferable that the urethane resin (I) is a urethane urea resin (i.e., it is preferable that it has urethane bonds and urea bonds). If the reaction raw materials contain amine compounds such as chain extenders, the urea bonds may be formed. In this specification, "constituent unit" refers to a repeating unit of a chemical structure formed during a reaction or polymerization.

[0035] In the liquid ink composition of this embodiment, the content of urethane resin (I) is preferably 30 to 100% by mass, more preferably 40 to 91% by mass, and even more preferably 50 to 81% by mass, based on the total resin solids content of the liquid ink composition. By setting the content of urethane resin (I) to 30% by mass or more, the amount of urethane resin (II), which is an optional component, can be freely adjusted to achieve the desired effect while maintaining pigment dispersibility. On the other hand, by setting the content of urethane resin (I) to 100% by mass or less, the properties of urethane resin (I) can be more easily reflected in the entire liquid ink composition. In the liquid ink composition of this embodiment, the content of urethane resin (I) is preferably 20 to 100% by mass, more preferably 35 to 96% by mass, and even more preferably 45 to 91% by mass, relative to the total resin solid content of the urethane resin component. By setting the content of urethane resin (I) to 20% by mass or more, good polyethylene extrusion lamination strength is achieved when printed on OPP film. On the other hand, by setting the content of urethane resin (I) to 100% by mass or less, the properties of urethane resin (I) are more easily reflected in the liquid ink composition as a whole.

[0036] The following describes the components of the reaction raw material (1) of the urethane resin (I) (a first isocyanate compound, polycarbonate, or a polyoxyalkylene compound having 3 to 4 carbon atoms, and optionally blended polyester polyols, optionally blended polyether polyols, and optionally blended aromatic polyols), followed by a description of the preferred form of the urethane resin (I).

[0037] <First isocyanate compound> As the first isocyanate compound used in the urethane resin (I) of this embodiment, various known first isocyanate compounds commonly used in the production of general polyurethane resins can be used, and among them, a first isocyanate compound having two or more isocyanate groups is preferred, and a first isocyanate compound is more preferred. Preferred first isocyanate compounds of this embodiment include aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates. The first isocyanate compound is defined by the following general formula (1): [ka] (In the above general formula (1), L 5 and L 6 Each of these independently represents a single bond or an alkylene group with 1 to 5 carbon atoms, M 2 (This represents a divalent organic group.) It is preferable that it be represented as follows: In the above general formula (1), L 5 It is preferable that the bond is a single bond or an alkylene group having 1 to 3 carbon atoms. In the above general formula (1), L 6 It is preferable that the bond is a single bond or an alkylene group having 1 to 3 carbon atoms. In the above general formula (1), the divalent organic group preferably has 1 to 20 carbon atoms, more preferably has 2 to 18 carbon atoms, and even more preferably has 3 to 17 carbon atoms. An "organic group" refers to a group having 1 or more carbon atoms, and is preferably a hydrocarbon group having 1 to 20 carbon atoms. The above divalent organic group is preferably an alkylene group having 1 to 20 carbon atoms, an alkenylene group having 1 to 20 carbon atoms, an alkylene oxy group having 1 to 20 carbon atoms, or an arylene group having 6 to 18 carbon atoms. Furthermore, one or more non-adjacent -CH2- in the alkylene group, alkenylene group, alkylene oxy group, or arylene group may be substituted with -O-, -COO-, or -OCO-. In the above general formula (1), M 2 It is preferable that the substituent is a linear, branched, or cyclic alkylene group having 3 to 12 carbon atoms, or an arylene group having 6 to 18 carbon atoms, without including the number of carbon atoms of the substituent. 2 Preferably, the substituents are alkyl groups or alkoxy groups.

[0038] Specific examples of the first isocyanate compound of this embodiment include, for example, 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyli isocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylenediisocyanate, 1,4-phenylenediisocyanate, tolylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropyl diisocyanate, methylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and lysine diisocyanate. Preferred are diisocyanates such as annetes, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, dimeryl diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanate-methyl)cyclohexane, methylcyclohexane diisocyanate, norbornane diisocyanate, m-tetramethylxylylene diisocyanate, 4,4-diphenylmethane diisocyanate, tolylene diisocyanate, bis-chloromethyl-diphenylmethane-diisocyanate, 2,6-diisocyanate-benzyl chloride, and dimer isocyanates obtained by converting the carboxyl groups of dimer acids to isocyanate groups. These first isocyanate compounds may be used individually or as a mixture of two or more. Among these, 4,4'-diphenylmethane diisocyanate, 4,4'-dibenzyluisocyanate, tolylene diisocyanate, hexamethylene diisocyanate, isopropyl diisocyanate, methylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanate-methyl)cyclohexane, methylcyclohexane diisocyanate, 4,4-diphenylmethane diisocyanate, and tolylene diisocyanate are more preferred, and tolylene diisocyanate or isophorone diisocyanate are even more preferred.

[0039] In the reaction raw material (1) of the urethane resin (I) of this embodiment, the proportion of the first isocyanate compound is preferably 5 to 60% by mass, more preferably 10 to 50% by mass, and even more preferably 15 to 40% by mass, relative to the total amount (100% by mass) of the reaction raw material (1). The content of the constituent units derived from the first isocyanate compound (so-called first isocyanate compound residues) in this embodiment is preferably in the range of 5 to 60% by mass relative to the total urethane resin (I) (resin solids), more preferably 10 to 50% by mass, and even more preferably 15 to 40% by mass. When the content of constituent units derived from the first isocyanate compound is 15% by mass or more per 100% by mass of urethane resin (I), it has the effect of improving the strength of polyethylene extruded laminates. When it is 40% by mass or less, it has the effect of improving the flexibility of the ink coating film (good conformability to the substrate).

[0040] <Polycarbonate> Examples of polycarbonates that can be used as reaction raw materials (1) for the urethane resin (I) of this embodiment include compounds obtained by reacting a carbonate ester and / or phosgene with a polyol. Therefore, the polycarbonate of this embodiment may preferably be a polycarbonate polyol, and more preferably a polycarbonate diol. Examples of the above-mentioned carbonate esters include dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, ethylene carbonate, propylene carbonate, butylene carbonate, diphenyl carbonate, dinaphthyl carbonate, and phenylnaphthyl carbonate. Examples of polyols used to obtain the aforementioned polycarbonate include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 1,6-hexanediol, 2,5-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, and 2-methyl-1,3-propanediol. Examples include aliphatic diols such as iodine, neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, and 2-methyl-1,8-octanediol; aliphatic cyclic structure-containing diols such as 1,4-cyclohexanedimethanol and hydrogenated bisphenol A; aromatic dihydroxy compounds such as hydroquinone, resorcinol, bisphenol A, bisphenol F, and 4,4'-biphenol; polyether polyols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol; and polyester polyols such as polyhexamethylene adipate, polyhexamethylene succinate, and polycaprolactone.

[0041] The number-average molecular weight (Mn) of the polycarbonate in this embodiment is 200 to 5000, preferably 250 to 2000, and more preferably 300 to 1000. The hydroxyl value of the polycarbonate in this embodiment is preferably 22.44 to 561 mgKOH / g, more preferably 56.1 to 448.8 mgKOH / g, and even more preferably 112.2 to 374 mgKOH / g. When the hydroxyl value of polycarbonate is within the above range, it is easier to control the urethane bond concentration to a predetermined value or higher, which can further improve the laminate strength. The hydroxyl value in this specification is calculated by the method described in the Examples section below. In this specification, the number-average and weight-average molecular weights are those measured by gel permeation chromatography (GPC) under the following conditions. Measurement device: High-speed GPC device (HLC-8220GPC manufactured by Tosoh Corporation) Columns: The following columns manufactured by Tosoh Corporation were used, connected in series. "TSKgel G5000" (7.8mm I.D. x 30cm) x 1 "TSKgel G4000" (7.8mm I.D. x 30cm) x 1 "TSKgel G3000" (7.8mm I.D. x 30cm) x 1 "TSKgel G2000" (7.8mmI.D. x 30cm) x 1 Detector: RI (Differential Refractometer) Column temperature: 40℃ Eluent: Tetrahydrofuran (THF) Flow rate: 1.0mL / min Injection volume: 100 μL (tetrahydrofuran solution with a sample concentration of 0.4% by mass) Standard samples: Calibration curves were prepared using the following standard polystyrene samples. [Standard polystyrene] TSKgel Standard Polystyrene A-500, manufactured by Tosoh Corporation. TSKgel Standard Polystyrene A-1000, manufactured by Tosoh Corporation. TSKgel Standard Polystyrene A-2500, manufactured by Tosoh Corporation. TSKgel Standard Polystyrene A-5000, manufactured by Tosoh Corporation. TSKgel Standard Polystyrene F-1, manufactured by Tosoh Corporation. TSKgel Standard Polystyrene F-2, manufactured by Tosoh Corporation. TSKgel Standard Polystyrene F-4, manufactured by Tosoh Corporation. TSKgel Standard Polystyrene F-10, manufactured by Tosoh Corporation. TSKgel Standard Polystyrene F-20, manufactured by Tosoh Corporation. TSKgel Standard Polystyrene F-40, manufactured by Tosoh Corporation. TSKgel Standard Polystyrene F-80, manufactured by Tosoh Corporation. TSKgel Standard Polystyrene F-128, manufactured by Tosoh Corporation. TSKgel Standard Polystyrene F-288, manufactured by Tosoh Corporation. TSKgel Standard Polystyrene F-550, manufactured by Tosoh Corporation.

[0042] In the reaction raw material (1) of the urethane resin (I) of this embodiment, the proportion of polycarbonate is preferably 0 to 40% by mass, more preferably 4 to 30% by mass, and even more preferably 5 to 20% by mass, relative to the total amount (100% by mass) of the reaction raw material (1). In this embodiment, the content of polycarbonate-derived constituent units (so-called polycarbonate residues) is preferably in the range of 0 to 40% by mass relative to the total urethane resin (I) (resin solids), more preferably 4 to 30% by mass, and even more preferably 5 to 28% by mass. When the content of the polycarbonate constituent units relative to the total urethane resin (I) (resin solids) is 5% by mass or more, the effect of improving the strength of polyethylene extruded laminate is achieved.

[0043] <Polyoxyalkylene compounds having 3 to 4 carbon atoms as constituent units> The polyoxyalkylene compound having 3 to 4 carbon atoms in this embodiment refers to a compound having a polyoxyalkylene skeleton in which 3 to 4 carbon atoms are linked together as repeating units, and is preferably represented by the following general formula (2). [ka] (In the above general formula (2), Q 1 (where n2 represents an alkylene group with 3 to 4 carbon atoms, and n2 represents the number of repeating units, which can be 1 to 200.) In the above general formula (2), (-Q2 -O-) can be a constituent unit. In addition, in the above general formula (2), the alkylene group having 3 to 4 carbon atoms is preferably an n-propylene group, an isopropylene group, an n-butylene group, an isobutylene group, a sec-butylene group, or a tert-butylene group. Furthermore, in the above general formula (2), n2 is preferably 1 to 100, and more preferably 2 to 30. Examples of polyoxyalkylene compounds having three to four carbon atoms include one or more selected from the group consisting of polytetramethylene ether glycol, polypropylene glycol, and polybutylene glycol, with polypropylene glycol being more preferred from the viewpoint of availability and price.

[0044] The number-average molecular weight (Mn) of the polyoxyalkylene compound in this embodiment is preferably 100 to 5000, more preferably 150 to 2000, and even more preferably 200 to 1000. The hydroxyl value of the polyoxyalkylene compound in this embodiment may preferably be 22.44 to 1122 mgKOH / g, more preferably 56.1 to 748 mgKOH / g, and even more preferably 112.2 to 561 mgKOH / g. When the hydroxyl value of the polyoxyalkylene compound is within the above range, it is easier to control the urethane bond concentration to a predetermined value or higher, which can further improve the laminate strength.

[0045] In the reaction raw material (1) of the urethane resin (I) of this embodiment, the proportion of the polyoxyalkylene compound having 3 to 4 carbon atoms is preferably 0 to 90% by mass, more preferably 2 to 90% by mass, even more preferably 3 to 50% by mass, and even more preferably 4 to 20% by mass, relative to the total amount (100% by mass) of the reaction raw material (1). The constituent units of this embodiment are derived from polyoxyalkylene compounds having 3 to 4 carbon atoms (the so-called polyoxyalkylene residues, for example, (-Q in the general formula (2) above). 2The content of -O-)) is preferably in the range of 2 to 90% by mass relative to the total urethane resin (I) (resin solids), and more preferably 4 to 20% by mass. When the content of the constituent units derived from the polyoxyalkylene compound is 4 parts by mass or more per 100 parts by mass of urethane resin (I), the extruded laminate strength tends to improve further.

[0046] <Polyester Polyol> The reaction raw material (1) of the urethane resin (I) in this embodiment may optionally contain polyester polyol. In particular, if the urethane resin (II) described later does not contain polyester polyol, it is preferable that the reaction raw material (1) of the urethane resin (I) contains polyester polyol. In the reaction raw material (1) of the urethane resin (I) of this embodiment, the proportion of the polyester polyol is preferably 0 to 90% by mass, and more preferably 40 to 80% by mass, relative to the total amount (100% by mass) of the reaction raw material (1). In this embodiment, the content of the constituent units of polyester polyol (constituent units derived from polyester polyol, so-called polyester polyol residues) is preferably in the range of 0 to 90% by mass relative to the total urethane resin (I) (resin solids), and more preferably 40 to 80% by mass. When the content of the constituent units of polyester polyol is 30 parts by mass or more per 100 parts by mass of urethane resin (I), the effect of improving heat resistance is achieved.

[0047] The polyester polyol of this embodiment can be, for example, one obtained by a known esterification reaction between a compound having two or more hydroxyl groups and a polybasic acid. More specifically, it is preferable to use a compound obtained by dehydration condensation or polymerization of a low molecular weight polyol and a polycarboxylic acid or an anhydride thereof. The lamination strength of the polyester polyol can be further increased by introducing ester groups to increase the cohesive energy.

[0048] As the low molecular weight polyol mentioned above, various known compounds having two or more hydroxyl groups that are commonly used in the production of known polyester polyols can be used. For example, one or more compounds may be used in combination as the polyester polyol. Specifically, as the low molecular weight polyol, for example, glycols such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol; 2-methyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,2-butanediol, 1,3-butanediol, 2-butyl-2- Branched glycols such as ethyl-1,3-propanediol, 1,2-propanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 2-isopropyl-1,4-butanediol, 2,4-dimethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2-ethyl-1,6-hexanediol, 3,5-heptanediol, and 2-methyl-1,8-octanediol can be used; glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, sorbitol, etc. can also be used.

[0049] As the polycarboxylic acid or anhydride thereof mentioned above, various known polycarboxylic acids commonly used in the production of known polyester polyols can be used. In addition, one or more compounds may be used in combination as the polycarboxylic acid or anhydride thereof. Specifically, for example, polycarboxylic acids having 6 or fewer carbon atoms and 2 or more carboxyl groups, such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, fumaric acid, maleic acid and anhydrides of these acids; aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid and anhydrides of these acids; aliphatic dicarboxylic acids such as pimelic acid, suberic acid, azelaic acid, sebacic acid, and dimer acid; tricarboxylic acids such as trimellitic acid and its anhydride; benzenetetracarboxylic acid, benzenepentacarboxylic acid, benzenehexacarboxylic acid and anhydrides of these acids can be used.

[0050] Furthermore, the polyester polyol may be any known polyester polyol commonly used in the production of polyurethane resins, such as cyclic ester compounds, including polyester polyols obtained by ring-opening polymerization of lactones such as polycaprolactone, polyvalerolactone, and poly(β-methyl-γ-valerolactone), or one or more compounds may be used in combination.

[0051] The number-average molecular weight of the polyester polyol is preferably in the range of 500 to 8,000, more preferably in the range of 800 to 7,000, and even more preferably in the range of 900 to 6,000.

[0052] The hydroxyl value of the polyester polyol in this embodiment is preferably 14.025 to 224.4 mgKOH / g, more preferably 16.02 to 140.25 mgKOH / g, and even more preferably 18.7 to 124.6 mgKOH / g. When the hydroxyl value of the polyester polyol is within the above range, it is easier to control the urethane bond concentration to a predetermined value or higher, which can further improve the laminate strength.

[0053] In this embodiment, it is preferable that at least one of the reaction raw material (1) for urethane resin (I) or the reaction raw material (2) for urethane resin (II) described later contains polyester polyol (or polyester polyol (II)). This makes it easier to adjust the urethane bond concentration, and as a result, it becomes easier to form an ink layer with an excellent balance of blocking resistance, adhesion, lamination suitability, scratch resistance, pigment dispersibility, fluidity, and storage (over time) stability.

[0054] <Aromatic polyols> The reaction raw material (1) of the urethane resin (I) of this embodiment contains a specific polyol compound (polycarbonate and / or a polyoxyalkylene compound having 3 to 4 carbon atoms as constituent units, and optionally a polyester polyol). Furthermore, an aromatic polyol compound may be added to the reaction raw material (1) as the polyol compound. That is, a preferred example of the urethane resin (I) of this embodiment uses a polycarbonate and / or a polyoxyalkylene compound having 3 to 4 carbon atoms as the reaction raw material (1), a polyester polyol, an aromatic polyol compound, and a first isocyanate compound. The aromatic polyol compound preferably has a substructure represented by the following general formula (3). The presence of an aromatic ring in the urethane resin (I) makes it easier to exhibit effects such as improved blocking properties, improved ink film gloss, and improved pigment dispersibility. In other words, the aromatic polyol compound of this embodiment preferably has a substructure represented by the following general formula (3). [ka] (In the above general formula (3), D 1 represents a hydrogen atom, a hydroxyl group, or an alkyl group having 1 to 15 carbon atoms, wherein one or more -CH2- in the alkyl group may be substituted with -O-, -COO-, or -OCO-. L 1 and L 2 Each of these independently represents a single bond or an alkylene group with 1 to 5 carbon atoms. L 4 Each of these independently represents a mezine group (-CH=), a trivalent alicyclic group with 3 to 15 carbon atoms, or a trivalent aromatic group. R 1 Each of these independently represents a monovalent aromatic group. M 1 Each of these independently represents a mezine group (-CH=), a trivalent alicyclic group with 3 to 15 carbon atoms, or a trivalent aromatic group. ni represents the number of repeating units and is an integer greater than or equal to 2. Note that * in the general formula (3) above represents a bond with another atom. In this embodiment, in the above general formula (3), D 1 It is preferable that this is a hydrogen atom, a hydroxyl group, or an alkyl group having 1 to 3 carbon atoms. In the above general formula (3), L 1 The group is preferably an alkylene group having 1 to 3 carbon atoms, and a methylene group is particularly preferred. In the above general formula (3), L 2 The alkylene group is preferably a single bond or has 1 to 3 carbon atoms, with a single bond being more preferable. L 4 It is preferable that R is a mezine group. 1 The atom is preferably a monovalent aromatic group that is unsubstituted or has 1 to 4 hydrogen atoms substituted by a substituent, and more preferably a phenyl group, naphthyl group, phenalenyl group, phenantrenyl group, anthryl group, azlenyl group, indenyl group, indanyl group, or tetralinyl group that is unsubstituted or has 1 to 3 hydrogen atoms substituted by a substituent. The substituent is preferably an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, or a halogen atom. In the above general formula (3), M 1 The group is preferably a mezine group or a trivalent alicyclic group having 4 to 8 carbon atoms (for example, a cyclohexane-triyl group which may be substituted with an alkyl group having 1 to 3 carbon atoms), and a mezine group is particularly preferred. In the above general formula (3), ni is preferably an integer between 2 and 50, and more preferably between 2 and 10.

[0055] The aromatic polyol compound of this embodiment more preferably has a structure represented by the following general formula (3-1). [ka] (In the above general formula (3), D 1 represents a hydrogen atom, a hydroxyl group, or an alkyl group having 1 to 15 carbon atoms, wherein one or more -CH2- in the alkyl group may be substituted with -O-, -COO-, or -OCO-. L 1 and L 2 Each of these independently represents a single bond or an alkylene group with 1 to 5 carbon atoms. M 1 Each of these independently represents a mezine group (-CH=), a trivalent alicyclic group with 3 to 15 carbon atoms, or a trivalent aromatic group. R 31 Each of these independently represents a halogen atom, an amino group, a cyano group, a hydroxyl group, or an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. n31 represents an integer from 0 to 4. ni represents the number of repeating units and is an integer greater than or equal to 2. Note that in the general formula (3-1) above, * represents a bond with another atom.

[0056] The number-average molecular weight (Mn) of the aromatic polyol compound in this embodiment is preferably 100 to 4000, more preferably 300 to 2000, and even more preferably 700 to 900. A number-average molecular weight (Mn) of the aromatic polyol compound between 700 and 900 is preferable from the viewpoint of balancing viscosity and hardness. If the number-average molecular weight of the aromatic polyol compound is too low, the cured urethane resin film tends to become hard, reducing its adhesion to the film. On the other hand, if the number-average molecular weight is too high, the cured urethane resin film tends to become brittle, reducing the blocking resistance of the ink film.

[0057] The hydroxyl value of the aromatic polyol compound in this embodiment is preferably 28.05 to 1122 mgKOH / g, more preferably 56.1 to 374 mgKOH / g, and even more preferably 124.66 to 160.28 mgKOH / g. When the hydroxyl value of the aromatic polyol compound is within the above range, it is easier to control the urethane bond concentration to a predetermined value or higher, which can further improve the laminate strength.

[0058] In the reaction raw material (1) of the urethane resin (I) of this embodiment, the proportion of the aromatic polyol compound is preferably 0 to 90% by mass, more preferably 0 to 40% by mass, and even more preferably 0 to 20% by mass, relative to the total amount (100% by mass) of the reaction raw material (1). In other words, by further containing structural units derived from aromatic polyol compounds, the urethane resin (I) can form an ink layer with an excellent balance of blocking resistance, adhesion, lamination suitability, scratch resistance, pigment dispersibility, fluidity, and storage (over time) stability. It is particularly preferable because it can improve lamination strength. Furthermore, it is preferable to further contain structural units derived from polyols as needed, as this can improve the dispersibility and fluidity of the ink and also improve adhesion. In this embodiment, the content of constituent units derived from aromatic polyol compounds (so-called aromatic polyol compound residues) is preferably in the range of 0 to 90% by mass relative to the total urethane resin (I) (resin solids), and more preferably 0 to 40% by mass. When the content of constituent units derived from aromatic polyol compounds is 3 parts by mass or more per 100 parts by mass of urethane resin (I), the solubility of the urethane resin (I) in ketone, ester, and alcohol-based solvents is ensured, and adhesion on the high-performance barrier film is improved. Furthermore, the resolubility of the ink film in the solvent is improved, and the tone reproduction of printed materials is enhanced. When the content is 20 parts by mass or less, the ink film has appropriate flexibility, making it easier to achieve good blocking resistance.

[0059] Furthermore, the reaction material (1) may further contain a polyether polyol and / or a polyol used in combination, if necessary. That is, the reaction material (1) must contain a specific polyol compound (polycarbonate and / or a polyoxyalkylene compound having 3 to 4 carbon atoms). The reaction material (1) may further contain one or more selected from the group consisting of polyester polyester polyol, the above aromatic polyol compound, polyether polyol, and a polyol used in combination, if necessary. In one embodiment of the urethane resin (I) of this embodiment, when polyester polyol and polyether polyol are used as part of the reaction raw materials (1), it is preferable that the mass proportion of polyester polyol is large in the total mass of the polyester polyol and polyether polyol. In the reaction raw material (1) of the urethane resin (I) of this embodiment, the total proportion of the polyester polyol and the polyether polyol is preferably 40 to 90% by mass, and more preferably 50 to 85% by mass, relative to the total amount (100% by mass) of the reaction raw material (1). In other words, it is preferable that the polyol structure of the urethane resin (I) has constituent units derived from polyester polyol, as this improves the lamination strength. Furthermore, it is preferable that it also has constituent units derived from polyether polyol, as this improves the dispersibility and fluidity of the ink and also improves adhesion.

[0060] (Properties of urethane resin (I)) The urethane bond concentration of the urethane resin (I) in this embodiment is preferably 0.4 mmol / g or more, more preferably 0.8 mmol / g to 4 mmol / g, and even more preferably in the range of 1.0 mmol / g to 1.5 mmol / g. Furthermore, when a relatively low molecular weight isocyanate raw material such as tolylene diisocyanate is used as the reaction raw material for the urethane resin (I), the urethane bond concentration is preferably 0.4 mmol / g or more, more preferably 0.8 mmol / g to 4 mmol / g, and even more preferably in the range of 1.15 mmol / g to 2.3 mmol / g. When the urethane bond concentration is 1.2 mmol / g or more, although the mechanism is unknown, the laminate strength tends to be particularly excellent. The urethane bond concentration of the urethane resin (I) can be calculated using the above formula (a). The weight-average molecular weight (Mw) of the urethane resin (I) in this embodiment is preferably 5,000 to 300,000, more preferably 10,000 to 200,000, and even more preferably 20,000 to 100,000. In particular, a weight-average molecular weight (Mw) of 50,000 to 100,000 for the urethane resin (I) is preferable in terms of the viscosity of the ink composition, blocking resistance, strength and oil resistance of the printed film, and gloss of the printed film.

[0061] (Preferred embodiment of urethane resin (I)) The urethane resin (I) of this embodiment is preferably a resin in which the urethane bond concentration is 0.4 mmol / g or more and 4 mmol / g or less, and which has urethane bonds and urea bonds, and which has polycarbonate and / or constituent units with 3 to 4 carbon atoms, a polyester polyol, and a first isocyanate compound as reaction raw materials (1). Liquid ink compositions containing urethane resin (I) are considered to be able to form an excellent ink layer by balancing blocking resistance, adhesion, lamination suitability, scratch resistance, pigment dispersibility, fluidity, and storage (over time) stability, using polycarbonate and / or polyoxyalkylene compounds having 3 to 4 carbon atoms as reaction raw materials (1), which exhibit excellent extrusion lamination strength, and because higher urethane bond concentrations tend to result in superior scratch resistance. Furthermore, it has been confirmed that by combining these with urethane resin (II) or binder resin as described later, an ink layer exhibiting excellent extrusion lamination strength can be formed.

[0062] (Organic solvents) Various organic solvents can be used as the organic solvent in the liquid ink composition of this embodiment. For example, it is preferable to use one or more selected from the group consisting of aromatic organic solvents, ketone-based organic solvents, ester-based organic solvents, alcohol-based organic solvents, and glycol ether-based organic solvents. Examples of the aromatic organic solvents include toluene and xylene. Examples of the ketone-based organic solvents include acetone, methyl ethyl ketone, and methyl isobutyl ketone. Examples of the ester-based organic solvents include ethyl acetate, n-propyl acetate, butyl acetate, and propylene glycol monomethyl ether acetate. The aforementioned alcohol-based organic solvent is preferably an aliphatic alcohol with a boiling point of less than 160°C, for example, an alcohol having 1 to 15 carbon atoms. Specifically, examples include n-propanol, inopropanol, n-butanol, propylene glycol monomethyl ether, 3-methyl-1-butanol, 2-methyl-1-butanol, 2,2-dimethyl-1-propanol, 3-methyl-2-butanol, 2-methyl-2-butanol, isobutanol, 2-pentanol, and the like. The glycol ether-based organic solvent is preferably a glycol ether solvent with a boiling point of 160°C or lower, and examples include at least one selected from the group consisting of ethylene glycol ethers and propylene glycol ethers. As the ethylene glycol ethers, ethylene glycol monoalkyl ethers are preferred, and as the propylene glycol ethers, propylene glycol monoalkyl ethers are preferred. The alkyl ether group in the ethylene glycol monoalkyl ether and propylene glycol monoalkyl ether is preferably one with 1 to 4 carbon atoms. Preferably, the ethylene glycol monoalkyl ether is ethylene glycol monopropyl ether or ethylene glycol mono(iso)propyl ether, and preferably the propylene glycol monoalkyl ether is propylene glycol monomethyl ether. The glycol ether-based organic solvent may be esterified, and examples include ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, and propylene glycol monoethyl ether acetate. These glycol ether-based organic solvents may be used individually or in combination of two or more. It is more preferable to use ethylene glycol monoalkyl ether and propylene glycol monoalkyl ether in combination. Specific examples of the glycol ether-based organic solvent include, for example, ethylene glycol monomethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol monoisopropyl ether, propylene glycol monomethyl ether, and propylene glycol mono-n-propyl ether. The above-mentioned organic solvents can be used individually or as a mixture of two or more of the exemplified organic solvents. In recent years, from the viewpoint of the working environment, it is preferable not to use aromatic organic solvents such as toluene and xylene, or ketone organic solvents.

[0063] The above-mentioned organic solvent preferably contains the above-mentioned ester-based organic solvent and alcohol-based organic solvent, and it is preferable to set the mass ratio so that the ester-based organic solvent:alcohol-based organic solvent = 1:1 to 9:1. When the mass ratio in the organic solvent is within this range, an ink with excellent printability and blocking resistance can be obtained. The mass ratio is more preferably 2:1 to 9:1, and even more preferably 2:1 to 8:1.

[0064] The liquid ink composition of this embodiment may contain water as a volatile component along with the organic solvent. Preferably, the water content is less than 10% by mass of the total amount of the ink composition. Adding water allows for control of the ink's drying properties, and in gravure printing in particular, it enables the clean reproduction of the characteristic gradient areas with minimal ink transfer. Furthermore, a water content of 1 to 5% by mass of the total amount of the liquid ink composition is particularly preferable, as it results in good printability. Furthermore, by adding water in this way, it is possible to reduce the amount of organic solvent components used. Water may be added to the organic solvent beforehand to form a hydrated mixed solvent, or a specific amount of water may be added separately. The liquid ink composition of this embodiment can be obtained as a liquid ink composition with excellent dispersibility and fluidity, whether it is a one-component type that does not use a curing agent such as an isocyanate curing agent, or a two-component type that uses a curing agent.

[0065] <Water> The liquid ink composition of this embodiment may contain water as needed. If the liquid ink composition contains water, the water content is preferably 0.1 to 10% by mass relative to the total liquid ink composition. By containing a predetermined amount of water, the pigment dispersibility of the urethane resin (I) and the optionally added binder resin is improved, and printability such as highlight transfer, plate cover, and trapping properties is improved. When the liquid ink composition of this embodiment contains water, the water content is preferably 0.5 to 7% by mass, more preferably 0.5 to 5% by mass, and even more preferably 0.5 to 4% by mass, relative to the total liquid ink composition. Furthermore, as described above, the printability is further improved by using it in combination with an alcohol-based organic solvent or a glycol ether-based organic solvent having a boiling point of 100 to 160°C.

[0066] When the liquid ink composition of this embodiment contains water, the mixing ratio of water to the alcohol-based organic solvent and / or glycol ether-based organic solvent (mass of water:mass of alcohol-based organic solvent and / or glycol ether-based organic solvent) is preferably 95:5 to 5:95, more preferably 90:10 to 10:90, and even more preferably 80:20 to 20:80. When the liquid ink composition of this embodiment contains water, the total content of water, the alcohol-based organic solvent, and the glycol ether-based organic solvent is preferably 1 to 20% by mass, more preferably 2 to 15% by mass, even more preferably 3 to 10% by mass, and particularly preferably 3 to 8% by mass, relative to the total liquid ink composition.

[0067] (Urethane resin (II)) The liquid ink composition of this embodiment may also contain a urethane resin (II) other than the urethane resin (I) described above. The liquid ink composition of this embodiment contains both a urethane resin (I) and a urethane resin (II) having a different chemical structure from the urethane resin (I). As a result, it has the function of improving ink adhesion as a binder resin and can also exhibit a greater function as a pigment dispersion resin. The urethane resin (II) in this embodiment is not particularly limited as long as it is a urethane resin other than the urethane resin (I) described above, has urethane bonds, and is obtained by reacting a polyol compound with a second isocyanate compound. The polyol compound is preferably one or more selected from the group consisting of polyester polyol (II), polyether polyol (II), and aromatic polyol compounds. Therefore, it is preferable that the urethane resin (II) uses a second isocyanate compound and a polyol compound as reaction raw materials (2). In other words, the urethane resin (II) in this embodiment has a structure in which a structural unit derived from the second isocyanate compound and a structural unit derived from the polyol compound are chemically bonded directly or indirectly. For convenience, in this specification, the reaction material for urethane resin (II) is referred to as reaction material (2), and the reaction material for urethane resin (I) is referred to as reaction material (1), thus distinguishing between the two.

[0068] In the liquid ink composition of this embodiment, when urethane resin (II) is included, the content of urethane resin (II) is preferably 5 to 90% by mass, more preferably 10 to 80% by mass, even more preferably 25 to 65% by mass, and even more preferably 30 to 55% by mass, based on the total resin solids content (100% by mass) of the liquid ink composition. By setting the content of urethane resin (II) to 40% by mass or more, the performance of urethane resin (II) is exhibited. On the other hand, by setting the content of urethane resin (II) to 10% by mass or less, the performance of urethane resin (I) is exhibited. In the liquid ink composition of this embodiment, if urethane resin (II) is included, the content of urethane resin (II) is preferably 5 to 90% by mass, more preferably 10 to 80% by mass, even more preferably 30 to 70% by mass, and even more preferably 40 to 60% by mass, based on the total resin solid content (100% by mass) of the urethane resin component.

[0069] <Second isocyanate compound> The reaction raw material (2) of the urethane resin (II) in this embodiment contains a second isocyanate compound. The second isocyanate compound used in the urethane resin (II) in the ink composition of this embodiment is preferably a compound having two or more isocyanate groups, and more preferably a diisocyanate compound. Examples of the second isocyanate compound include various known aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates that are commonly used in the production of known polyurethane resins, similar to the first isocyanate compound described above. As the second isocyanate compound, the same compounds as the first isocyanate compound can be used, for example, 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyli isocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylenediisocyanate, 1,4-phenylenediisocyanate, tolylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropyl diisocyanate, methylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate Examples include diisocyanates, lysine diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, dimeryl diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanate-methyl)cyclohexane, methylcyclohexane diisocyanate, norbornane diisocyanate, m-tetramethylxylylene diisocyanate, 4,4-diphenylmethane diisocyanate, tolylene diisocyanate, bis-chloromethyl-diphenylmethane-diisocyanate, 2,6-diisocyanate-benzyl chloride, and dimer diisocyanates obtained by converting the carboxyl group of a dimer acid to an isocyanate group. These second isocyanate compounds can be used individually or in combination of two or more.

[0070] In the reaction raw material (2) of the urethane resin (II) of this embodiment, the proportion of the second isocyanate compound is preferably 5 to 50% by mass, and more preferably 15 to 40% by mass, relative to the total amount (100% by mass) of the reaction raw material (2). Furthermore, the content of constituent units derived from the second isocyanate compound (so-called second isocyanate compound residues) in the urethane resin (II) is preferably in the range of 5 to 50% by mass, more preferably in the range of 10 to 40% by mass, relative to the urethane resin (II).

[0071] <Polyol compounds> The reaction raw material (2) of the urethane resin (II) in this embodiment contains at least a polyol compound. The polyol compound may be one or more selected from the group consisting of polyester polyol (II), polyether polyol (II), and aromatic polyol compounds. <<Polyester Polyol (II)>> In this embodiment, the reaction raw material (2) of the urethane resin (II) preferably contains at least polyester polyol (II). In one embodiment of the urethane resin (II) of this embodiment, when polyester polyol (II) and polyether polyol (II) are used as part of the reaction raw materials (2), it is preferable that the mass proportion of polyester polyol (II) is large in the total mass of the polyester polyol (II) and polyether polyol (II). In the reaction raw material (2) of the urethane resin (II) of this embodiment, the total proportion of the polyester polyol (II) and the polyether polyol (II) is preferably 20 to 95% by mass, and more preferably 50 to 90% by mass, relative to the total amount (100% by mass) of the reaction raw material (2). In the reaction raw material (2) of the urethane resin (II) of this embodiment, the proportion of polyester polyol (II) is preferably 0 to 95% by mass, and more preferably 30 to 90% by mass, relative to the total amount (100% by mass) of the reaction raw material (2). In other words, it is preferable that the polyol structure in the urethane resin (II) contains constituent units derived from polyester polyol (II), as this improves the lamination strength and heat resistance. Furthermore, it is preferable that the polyol structure further contains constituent units derived from polyether polyol (II) and / or aromatic polyol compounds, as this improves the dispersibility and fluidity of the ink and also improves adhesion.

[0072] In this embodiment, the mass ratio (polyester polyol(II):polyether polyol(II)) of polyester polyol(II) and polyether polyol(II) in the polyol structure (a structure having two or more hydroxyl groups) is preferably in the range of 45:55 to 100:0, more preferably in the range of 50:50 to 100:0, and even more preferably in the range of 55:45 to 99:1. It is preferable that the mass ratio of the polyester polyol(II) and polyether polyol(II) is within the range of 45:55 to 100:0, as this allows for the production of printed materials that are less prone to blocking. It is also preferable that the mass ratio is within the range of 55:45 to 99:1, as this allows for the production of an ink with particularly excellent lamination strength, adhesion, and ink dispersibility. Furthermore, in the liquid ink composition of this embodiment, when a polyvinyl butyral resin is used as a binder resin, good compatibility can be obtained if the mass ratio of the polyester polyol (II) and polyether polyol (II) is within the range of 55:45 to 99:1, thus providing suitable storage stability and fluidity.

[0073] The polyester polyol (II) in this embodiment is preferably a compound obtained by dehydration condensation or polymerization of a low molecular weight polyol with a polycarboxylic acid or an anhydride thereof. The lamination strength of the polyester polyol (II) can be further increased by introducing ester groups to increase the cohesive energy.

[0074] As the low molecular weight polyol mentioned above, various known compounds having two or more hydroxyl groups that are commonly used in the production of known polyester polyols can be used. For example, one or more compounds may be used in combination as polyester polyol(II). Specifically, as the low molecular weight polyol, for example, glycols such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol; 2-methyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,2-butanediol, 1,3-butanediol, 2-butyl-2- Branched glycols such as ethyl-1,3-propanediol, 1,2-propanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 2-isopropyl-1,4-butanediol, 2,4-dimethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2-ethyl-1,6-hexanediol, 3,5-heptanediol, and 2-methyl-1,8-octanediol can be used; glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, sorbitol, etc. can also be used.

[0075] As the polycarboxylic acid or anhydride thereof mentioned above, various known polycarboxylic acids commonly used in the production of known polyester polyols can be used. In addition, one or more compounds may be used in combination as the polycarboxylic acid or anhydride thereof. Specifically, for example, polycarboxylic acids having 6 or fewer carbon atoms and 2 or more carboxyl groups, such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, fumaric acid, maleic acid and anhydrides of these acids; aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid and anhydrides of these acids; aliphatic dicarboxylic acids such as pimelic acid, suberic acid, azelaic acid, sebacic acid, and dimer acid; tricarboxylic acids such as trimellitic acid and its anhydride; benzenetetracarboxylic acid, benzenepentacarboxylic acid, benzenehexacarboxylic acid and anhydrides of these acids can be used.

[0076] Furthermore, the polyester polyol(II) may be any known polyester polyol commonly used in the production of polyurethane resins, such as cyclic ester compounds, including polyester polyols obtained by ring-opening polymerization of lactones such as polycaprolactone, polyvalerolactone, and poly(β-methyl-γ-valerolactone), or one or more compounds may be used in combination.

[0077] The number average molecular weight of the polyester polyol(II) is preferably in the range of 500 to 8,000, more preferably in the range of 800 to 7,000, and even more preferably in the range of 900 to 6,000. The hydroxyl value of the polyester polyol(II) in this embodiment is preferably 14.025 to 224.4 mgKOH / g, more preferably 16.028 to 140.25 mgKOH / g, and even more preferably 18.7 to 124.66 mgKOH / g. When the hydroxyl value of polyester polyol(II) is within the above range, it is easier to control the urethane bond concentration to a predetermined value or higher, which can further improve the laminate strength.

[0078] The content of the constituent units of polyester polyol (II) is preferably in the range of 0 to 90% by mass, more preferably in the range of 0 to 80% by mass, relative to the urethane resin (II). When the amount of polyester polyol (II) is 50 parts by mass or more per 100 parts by mass of urethane resin (II), the solubility of the urethane resin (II) in ketone, ester, and alcohol-based solvents is ensured, and adhesion on the high-performance barrier film is good. Furthermore, the resolubility of the ink film in the solvent is good, improving the tone reproducibility of printed materials. When the amount is 40 parts by mass or less, the ink film has appropriate flexibility, which tends to result in good blocking resistance.

[0079] <<Polyether polyol(II)>> The reaction raw material (2) of the urethane resin (II) in this embodiment may contain a polyether polyol (II) other than the polyoxyalkylene compound having 3 to 4 carbon atoms, which is a component of the reaction raw material (1). The polyether polyol (II) as an optional component of the reaction raw material (2) can be any polyether polyol commonly used in the production of known polyurethane resins, and can be any polyether polyol other than the polyoxyalkylene compound having 3 to 4 carbon atoms, which is a component of the reaction raw material (1). In addition, one or more types of polyether polyol (II) may be used in combination. Examples include polyether polyols of polymers or copolymers of methylene oxide, ethylene oxide, propylene oxide, tetrahydrofuran, etc. Specifically, known and commonly used ones such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol may be used. By including a polyether polyol, adhesion, especially on high-performance barrier films, is greatly improved, resulting in superior blocking resistance and lamination strength.

[0080] The number average molecular weight of the polyether polyol(II) is preferably 100 to 3500. If the number average molecular weight of the polyether polyol(II) is less than 100, the polyurethane resin film tends to harden, and its adhesion to the polyester film decreases. If the number average molecular weight is greater than 3500, the resulting resin film tends to be brittle, and the blocking resistance of the ink film decreases. The hydroxyl value of the polyether polyol(II) in this embodiment is preferably 22.44 to 561 mgKOH / g, more preferably 56.1 to 448.8 mgKOH / g, and even more preferably 112.2 to 374 mgKOH / g. When the hydroxyl value of polyether polyol(II) is within the above range, it is easier to control the urethane bond concentration to a predetermined value or higher, which can further improve the laminate strength.

[0081] In the reaction raw material (2) of the urethane resin (II) of this embodiment, the proportion of the polyether polyol (II) is preferably 0 to 60% by mass, and more preferably 0 to 50% by mass, relative to the total amount (100% by mass) of the reaction raw material (2). The constituent units of polyether polyol (II) are preferably contained in an amount of 0 to 50% by mass relative to the urethane resin (II). When the polyether polyol is 5 parts by mass or more per 100 parts by mass of urethane resin (II), the solubility of the urethane resin (II) in ketone, ester, and alcohol-based solvents is ensured, and adhesion on the high-performance barrier film is good. Furthermore, the resolubility of the ink film in the solvent is good, improving the tone reproduction of printed materials. When the amount is 30 parts by mass or less, the ink film has appropriate flexibility, which tends to result in good blocking resistance.

[0082] <Aromatic polyol compounds> The reaction raw material (2) of the urethane resin (II) in this embodiment contains a polyol compound as an essential component. Furthermore, the reaction raw material (2) may contain an aromatic polyol compound as the polyol compound. The aromatic polyol compound preferably has a substructure represented by the general formula (3), more preferably general formula (3-1). The presence of an aromatic ring in the urethane resin (II) makes it easier to exhibit effects such as improved blocking properties, improved ink film gloss, and improved pigment dispersibility.

[0083] In the reaction raw material (2) of the urethane resin (II) of this embodiment, the proportion of the aromatic polyol compound is preferably 0 to 95% by mass, more preferably 0 to 90% by mass, and even more preferably 0 to 87% by mass, relative to the total amount (100% by mass) of the reaction raw material (2). In other words, it is preferable that the polyol structure of the urethane resin (II) has structural units derived from aromatic polyol compounds, as this improves the lamination strength. Furthermore, it is preferable to have structural units derived from other polyols as needed, as this improves the dispersibility and fluidity of the ink and also improves adhesion. In this embodiment, the content of constituent units derived from aromatic polyol compounds (so-called aromatic polyol compound residues) is preferably in the range of 30 to 95% by mass relative to the total urethane resin (II) (resin solids), and more preferably 50 to 90% by mass. When the content of constituent units derived from aromatic polyol compounds is 50 parts by mass or more per 100 parts by mass of urethane resin (II), the solubility of the urethane resin (II) in ketone, ester, and alcohol-based solvents is ensured, and adhesion on the high-performance barrier film is improved. Furthermore, the resolubility of the ink film in the solvent is improved, and the tone reproducibility of printed materials is enhanced. When the content is 90 parts by mass or less, the ink film has appropriate flexibility, making it easier to achieve good blocking resistance.

[0084] (Properties of urethane resin (II)) The urethane bond concentration of the urethane resin (II) in this embodiment is preferably 0.98 mmol / g or more, more preferably 1.1 mmol / g or more and 5.0 mmol / g or less, and even more preferably in the range of 1.2 mmol / g or more and 3.0 mmol / g or less. The urethane bond concentration of the urethane resin (II) can be calculated using the above formula (a). The weight-average molecular weight (Mw) of the urethane resin (II) in this embodiment is preferably 1,000 to 300,000, more preferably 2,000 to 200,000, and even more preferably 5,000 to 100,000. A weight-average molecular weight (Mw) of urethane resin (II) of 5,000 to 150,000 is preferable in terms of the blocking resistance of the ink composition, the strength and oil resistance of the printed film, and the gloss of the printed film.

[0085] (Preferred embodiment of urethane resin (II)) The preferred urethane resin (II) in this embodiment may be one or two resins selected from the group consisting of a resin using a polyol compound containing the above-mentioned polyester polyol (II) and polyethylene glycol that does not contain carbonate groups ((-O-(C=O)-O-)) and a second isocyanate compound as reaction raw materials (2), and a resin using a polyol compound containing the above-mentioned polyester polyol (II) and two aromatic polyols that do not contain carbonate groups ((-O-(C=O)-O-)) and a second isocyanate compound as reaction raw materials (2). This allows for the formation of an ink layer with an excellent balance of blocking resistance, adhesion, lamination suitability, scratch resistance, pigment dispersibility, fluidity, and storage (over time) stability.

[0086] (Preferred embodiments of urethane resins (I) and (II)) In the liquid ink composition of this embodiment, the total amount of urethane resin (I) and urethane resin (II) is preferably 30 to 100% by mass, more preferably 40 to 80% by mass, and even more preferably 45 to 70% by mass, relative to the total resin solids content of the liquid ink composition. When the content of urethane resins (I) and (II) in the liquid ink composition is within the above range, an ink layer with superior blocking resistance, adhesion, suitability for boiling and laminating, scratch resistance, pigment dispersibility, fluidity, and storage (over time) stability can be formed. In the liquid ink composition of this embodiment, the total amount of urethane resin (I), urethane resin (II), and organic solvent is preferably 20 to 100% by mass, more preferably 30 to 95% by mass, and even more preferably 40 to 90% by mass, based on the total amount of the liquid ink composition. In the liquid ink composition of this embodiment, the total amount of urethane resin (I), urethane resin (II), organic solvent, and pigment is preferably 30 to 100% by mass, more preferably 40 to 100% by mass, and even more preferably 50 to 100% by mass, based on the total amount of the liquid ink composition. In the liquid ink composition of this embodiment, the total amount of urethane resin (I), urethane resin (II), organic solvent, pigment, and polyvinyl butyral resin is preferably 31 to 100% by mass, more preferably 41 to 100% by mass, and even more preferably 51 to 100% by mass, based on the total amount of the liquid ink composition. In the liquid ink composition of this embodiment, the total amount of urethane resin (I), urethane resin (II), organic solvent, pigment, and other resins is preferably 40 to 100% by mass, more preferably 60 to 100% by mass, and even more preferably 80 to 100% by mass, based on the total amount of the liquid ink composition. In the liquid ink composition of this embodiment, it is preferable that the proportion of the total solid content of the urethane resin component to the total solid content of the binder resin is 50% by mass or more, 57% by mass or more, 61% by mass or more, or 67% by mass or more. Furthermore, it is preferable that the upper limit of the proportion of the total solid content of the urethane resin component to the total solid content of the binder resin is 100% by mass or less, 95% by mass or less, or 90% by mass or less. The upper and lower limits can be arbitrarily combined.

[0087] The reaction raw material (1) for urethane resin (I) and / or the reaction raw material (2) for urethane resin (II) of this embodiment may further contain a polyol in combination as needed. As the polyol used in combination with the urethane resin (I) and / or (II) used in the liquid ink composition of this embodiment, various known polyols commonly used in the production of polyurethane resins can be used, and one or more may be used in combination. For example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1,5-pentanediol, hexanediol, octanediol, 1,4-butynediol, 1,4-butylenediol, diethylene glycol, triethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, trimethylolethane, 1,2,6-hexanetriol, 1,2,4-butanetriol, sorbitol, pentaestritol, etc. Examples include saturated or unsaturated low molecular weight polyols (1); polycarbonate polyols obtained by reacting the low molecular weight polyols with, for example, dimethyl carbonate, diphenyl carbonate, ethylene carbonate, phosgene, etc. (2); polybutadiene glycols (3); glycols obtained by adding ethylene oxide or propylene oxide to bisphenol A (4); and acrylic polyols (4) obtained by copolymerizing one or more hydroxyethyl acrylates, hydroxypropyl acrylates, hydroxybutyl acrylates, etc., or their corresponding methacrylic acid derivatives, etc., with, for example, acrylic acid, methacrylic acid, or their esters. Furthermore, it is preferable not to use polyol compounds having a carbonate group ((-O-(C=O)-O-)), such as polycarbonate polyols, as the reaction raw material (2) for the urethane resin (II).

[0088] Furthermore, if the combined polyol described above includes polyester polyol (including polyester polyol (I) and (II)) and / or polyether polyol (including polyether polyol (I) and (II)), the content of the polyester polyol and / or polyether polyol contained in the combined polyol is also included in the mass of the polyester polyol and / or polyether polyol in the polyol structure of the urethane resin (I) and / or urethane resin (II), respectively.

[0089] Furthermore, in the liquid ink composition of this embodiment, it is preferable that at least one of the urethane bond concentration of urethane resin (I) or urethane bond concentration of urethane resin (II) is 0.98 mmol / g or more, more preferably 1.0 mmol / g or more and 4.0 mmol / g or less, and even more preferably in the range of 1.05 mmol / g or more and 2.0 mmol / g or less. If at least one of the urethane bond concentration of urethane resin (I) or urethane bond concentration of urethane resin (II) is 0.98 mmol / g or higher, it becomes easier to control the overall urethane bond concentration of the urethane resin components to 0.98 mmol / g or higher. Since a higher urethane bond concentration tends to result in a harder coating film, it is possible to provide an ink composition with particularly excellent scratch resistance.

[0090] (Method for producing urethane resins (I) and (II)) The polyurethane resins (I) and (II) in the liquid ink composition of this embodiment are produced by, for example, a two-step method in which polyols having two or more hydroxyl groups and isocyanates are reacted in a proportion that results in an excess of isocyanate groups to obtain a prepolymer with terminal isocyanate groups, and the obtained prepolymer is reacted with a chain extender and / or a chelating agent in a suitable solvent, or by a one-step method in which polyols having two or more hydroxyl groups, isocyanates, a chain extender and / or a chelating agent are reacted all at once in a suitable solvent from among the above. Examples of polyols having two or more hydroxyl groups include one or more selected from the group consisting of polycarbonate or polyoxyalkylene compounds having 3 to 4 carbon atoms, polyester polyols, polyester polyols (II), polyether polyols (II), and aromatic polyol compounds, as well as a combination polyol that may be added as needed. The isocyanates include one or more compounds selected from the group consisting of a first isocyanate compound and a second isocyanate compound. The aforementioned solvents include ester solvents such as ethyl acetate, propyl acetate, and butyl acetate, which are commonly used as solvents for non-toluene gravure inks; ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; alcohol solvents such as methanol, ethanol, isopropyl alcohol, and n-butanol; hydrocarbon solvents such as methylcyclohexane and ethylcyclohexane; or mixtures thereof. Among the above methods, the two-stage method is preferred for obtaining a uniform urethane resin (I) or (II). Furthermore, when producing urethane resin (I) or (II) by the two-stage method, it is preferable to react them so that the total (equivalent ratio) of amino groups of the chain extender and / or end-capping agent is in a ratio of 1 / 0.9 to 1.3. If the equivalent ratio of isocyanate groups to amino groups is less than 1 / 1.3, the chain extender and / or end-capping agent may remain unreacted, which may cause the urethane resin to yellow or produce an odor after printing. Furthermore, in recent years, from the perspective of the working environment, it has become more preferable to avoid using aromatic solvents such as toluene and xylene, as well as ketone solvents. In the liquid ink composition of this embodiment, the chain extenders used in the polyurethane resin include ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine, dicyclohexylmethane-4,4'-diamine, and amines having hydroxyl groups in their molecules, such as 2-hydroxyethylethylenediamine, 2-hydroxyethylpropyldiamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypyropyrethylenediamine, di-2-hydroxypyropyrethylenediamine, and di-2-hydroxypropylethylenediamine. These chain extenders can be used individually or in combination of two or more. Furthermore, monovalent active hydrogen compounds can be used as end-capping agents to stop the reaction. Examples of such compounds include monoamines such as diethanolamine, monoethanolamine, aminomethylpropanol, cyclohexylamine, and dibutylamine, as well as alcohols such as ethanol and isopropyl alcohol. In addition, when it is particularly desirable to introduce carboxyl groups into polyurethane resins, amino acids such as glycine and L-alanine can be used as reaction stoppers. These end-capping agents can be used individually or in combination of two or more.

[0091] (Pigment) The pigment used in the liquid ink composition of this embodiment may be either a colored pigment or a white pigment. The pigment is not particularly limited and may include organic or inorganic pigments used in general inks, paints, and recording agents. It is preferable that the pigment be an organic pigment in order to particularly exhibit the excellent effect of this disclosure in improving storage stability. Examples of organic pigments include condensed polycyclic organic pigments with benzene rings or heterocyclic structures, azo pigments, and the like. Specific examples of preferred organic pigments are listed below.

[0092] Azo pigments can be any organic pigment having an azo group (-N=N-) in their molecule, and may be soluble azo lake pigments, insoluble azo pigments, or condensed azo pigments. Examples of azo pigments include CI Pigment Red 10, CI Pigment Red 11, CI Pigment Red 112, CI Pigment Red 114, CI Pigment Red 119, CI Pigment Red 12, CI Pigment Red 136, CI Pigment Red 14, CI Pigment Red 144, CI Pigment Red 146, CI Pigment Red 147, CI Pigment Red 15, CI Pigment Red 150, and CI Pigment Red 1 6, CI Pigment Red 164, CI Pigment Red 166, CI Pigment Red 17, CI Pigment Red 170, CI Pigment Red 171, CI Pigment Red 175, CI Pigment Red 176, CI Pigment Red 18, CI Pigment Red 183, CI Pigment Red 184, CI Pigment Red 185, CI Pigment Red 187, CI Pigment Red 188, CI Pigment Red 193, CI Pigment Tread 2, CI Pigment Red 200, CI Pigment Red 208, CI Pigment Red 21, CI Pigment Red 210, CI Pigment Red 211, CI Pigment Red 213, CI Pigment Red 214, CI Pigment Red 22, CI Pigment Red 220, CI Pigment Red 221, CI Pigment Red 23, CI Pigment Red 237, CI Pigment Red 238, CI Pigment Red 239, CI P Pigment Red 242, CI Pigment Red 243, CI Pigment Red 245, CI Pigment Red 247, CI Pigment Red 253, CI Pigment Red 256, CI Pigment Red 258, CI Pigment Red 266, CI Pigment Red 268, CI Pigment Red 269, CI Pigment Red 3, CI Pigment Red 31, CI Pigment Red 32, CI Pigment Red 38, CI Pigment Red 4, CIPigment Red 41, CI Pigment Red 48, CI Pigment Red 48:1, CI Pigment Red 48:2, CI Pigment Red 48:3, CI Pigment Red 48:4, CI Pigment Red 49, CI Pigment Red 49:1, CI Pigment Red 49:2, CI Pigment Red 5, CI Pigment Red 50:1, CI Pigment Red 52:1, CI Pigment Red 52:2, CI Pigment Red 53:1, CI Pigment Red 54, CI Pigment Tread 57:1, CI Pigment Red 58, CI Pigment Red 58:4, CI Pigment Red 6, CI Pigment Red 60, CI Pigment Red 60:1, CI Pigment Red 63, CI Pigment Red 63:1, CI Pigment Red 63:2, CI Pigment Red 64:1, CI Pigment Red 68, CI Pigment Red 7, CI Pigment Red 8, CI Pigment Red 9, CI Pigment Red 95, CI Pigment Yellow 1, CI Pigment Yellow Low 10, CI Pigment Yellow 100, CI Pigment Yellow 104, CI Pigment Yellow 105, CI Pigment Yellow 106, CI Pigment Yellow 111, CI Pigment Yellow 113, CI Pigment Yellow 114, CI Pigment Yellow 116, CI Pigment Yellow 12, CI Pigment Yellow 120, CI Pigment Yellow 124, CI Pigment Yellow 126, CI Pigment Yellow 127, CI Pigment Yellow 128, CI Pig CI Pigment Yellow 13, CI Pigment Yellow 130, CI Pigment Yellow 133, CI Pigment Yellow 14, CI Pigment Yellow 15, CI Pigment Yellow 151, CI Pigment Yellow 152, CI Pigment Yellow 154, CI Pigment Yellow 155, CI Pigment Yellow 16, CI Pigment Yellow 165, CI Pigment Yellow 166, CI Pigment Yellow 167, CI Pigment Yellow 168, CI Pigment Yellow 169, CIPigment Yellow 17, CI Pigment Yellow 170, CI Pigment Yellow 172, CI Pigment Yellow 174, CI Pigment Yellow 175, CI Pigment Yellow 176, CI Pigment Yellow 180, CI Pigment Yellow 181, CI Pigment Yellow 183, CI Pigment Yellow 191, CI Pigment Yellow 191:1, CI Pigment Yellow 194, CI Pigment Yellow 2, CI Pigment Yellow 205, CI Pigment Yellow 2 06, CI Pigment Yellow 209, CI Pigment Yellow 212, CI Pigment Yellow 214, CI Pigment Yellow 219, CI Pigment Yellow 3, CI Pigment Yellow 4, CI Pigment Yellow 49, CI Pigment Yellow 5, CI Pigment Yellow 55, CI Pigment Yellow 6, CI Pigment Yellow 60, CI Pigment Yellow 61, CI Pigment Yellow 62, CI Pigment Yellow 63, CI Pigment Yellow 65, CI Pigment Yellow 7, CI Pigment Yellow 73, CI Pigment Yellow 74, CI Pigment Yellow 75, CI Pigment Yellow 77, CI Pigment Yellow 81, CI Pigment Yellow 83, CI Pigment Yellow 87, CI Pigment Yellow 9, CI Pigment Yellow 93, CI Pigment Yellow 94, CI Pigment Yellow 95, CI Pigment Yellow 97, CI Pigment Yellow 98, CI Pigment Orange 1, CI Pigment Orange 13, CI Pig Pigment Orange 15, CI Pigment Orange 16, CI Pigment Orange 17, CI Pigment Orange 17:1, CI Pigment Orange 19, CI Pigment Orange 2, CI Pigment Orange 22, CI Pigment Orange 24, CI Pigment Orange 3, CI Pigment Orange 34, CI Pigment Orange 36, CI Pigment Orange 38, CI Pigment Orange 4, CI Pigment Orange 46, CI Pigment Orange 5, CI Pigment Orange 60, CIExamples include Pigment Orange 62, CI Pigment Orange 64, CI Pigment Orange 72, CI Pigment Orange 74, CI Pigment Brown 25, CI Pigment Brown 32, CI Pigment Brown 5, CI Pigment Blue 25, CI Pigment Blue 26, CI Pigment Violet 13, CI Pigment Violet 17, CI Pigment Violet 32, and CI Pigment Violet 50. These can be used individually or in combination.

[0093] Among the azo pigments, CI Pigment Red 57:1 (PR57:1), CI Pigment Red 146 (PR146), CI Pigment Yellow 13 (PY13), CI Pigment Yellow 55 (PY55), CI Pigment Yellow 83 (PY83), CI Pigment Yellow 180 (PY180), and CI Pigment Range 13 (PO13) are particularly preferred.

[0094] The primary particle size of the above azo pigment is, for example, 0.01 to 1.0 μm, preferably 0.1 to 0.6 μm. The specific surface area of ​​the above azo pigment is, for example, 10 to 150 m². 2 / g, preferably 20-100m 2 The value is / g. When the primary particle size and specific surface area are within the above range, a pigment with excellent coloring power and dispersibility can be obtained.

[0095] Furthermore, condensed polycyclic organic pigments can also be used as coloring pigments. Condensed polycyclic organic pigments refer to organic pigments that have a cyclic structure containing benzene rings or heterocycles. Examples of condensed polycyclic organic pigments used in this invention include CI Pigment Blue 15, CI Pigment Blue 15:1, CI Pigment Blue 15:2, CI Pigment Blue 15:3, CI Pigment Blue 15:4, CI Pigment Blue 15:5, CI Pigment Blue 15:6, CI Pigment Blue 16, CI Pigment Blue 17, CI Pigment Blue 75, CI Pigment Blue 79, CI Pigment Green 7, and CI Pigment Green 36. CI Pigment Green 58, CI Pigment Green 59, CI Pigment Green 62, CI Pigment Green 63 and other phthalocyanine pigments, CI Pigment Violet 19, CI Pigment Violet 42, CI Pigment Violet 55, CI Pigment Red 122, CI Pigment Red 202, CI Pigment Red 206, CI Pigment Red 207, CI Pigment Red 209, CI Pigment Orange 48, CI Quinacridone pigments such as Pigment Orange 49, dioxazine pigments such as CI Pigment Violet 23, CI Pigment Violet 34, CI Pigment Violet 35, CI Pigment Violet 37, CI Pigment Blue 80, perylene pigments such as CI Pigment Red 123, CI Pigment Red 149, CI Pigment Red 178, CI Pigment Red 179, CI Pigment Red 190, CI Pigment Red 224, CI Pigment Violet 29, CI Pigment Black 31, CI Pigment Black 32, perinone pigments such as CI Pigment Orange 43, CI Pigment Red 194, isoindolinone pigments such as CI Pigment Yellow 109, CI Pigment Yellow 110, CI Pigment Yellow 173, CI Pigment Yellow 179, CI Pigment Orange 61, CI Pigment Brown 38, CI Pigment Yellow 139, CIIsoindoline pigments such as Pigment Yellow 185, CI Pigment Orange 66, CI Pigment Orange 69, CI Pigment Red 260; thioindigo pigments such as CI Pigment Red 88, CI Pigment Red 181, CI Pigment Red 279, CI Pigment Violet 36, CI Pigment Violet 38; CI Pigment Red 83, CI Pigment Red 89, CI Pigment Red 168, CI Pigment Red 177, CI Pigment Red 182, CI Pigment Red 216, CI Pigment Red 226, CI Pigment Red 251, CI Pigment Red 263, CI Pigment Blue 60, CI Pigment Yellow 24, CI Pigment Yellow 99, CI Pigment Yellow 108, CI Pigment Yellow 123, CI Pigment Yellow 199, CI Pigment Violet 31, CI Pigment Orange 4 Examples include anthraquinone pigments such as CI Pigment Orange 51, CI Pigment Violet 5:1, and CI Pigment Black 20; quinophthalone pigments such as CI Pigment Yellow 138 and CI Pigment Yellow 231; diketopyrrolopyrrole pigments such as CI Pigment Orange 71, CI Pigment Orange 73, CI Pigment Orange 81, CI Pigment Red 254, CI Pigment Red 255, CI Pigment Red 264, CI Pigment Red 270, and CI Pigment Red 272; and metal complex pigments such as CI Pigment Yellow 117, CI Pigment Yellow 129, CI Pigment Yellow 150, CI Pigment Yellow 153, CI Pigment Orange 65, CI Pigment Orange 68, CI Pigment Red 257, CI Pigment Red 271, CI Pigment Green 8, and CI Pigment Green 10.

[0096] The condensed polycyclic organic pigment used in this embodiment may be a commercially available product or may be manufactured by a known and conventional method. Of course, it may also be used after manufacturing by adding any known treatments as appropriate, for example, by adding pigment derivative treatment, surfactant treatment, rosin treatment, or resin treatment. Furthermore, the pigment particle size, particle morphology, and particle surface charge may be adjusted and controlled for use in printing inks, paints, colored molded products, stationery, textile printing, toner, color filters, inkjet inks, and cosmetics. When a condensed polycyclic organic pigment with a high specific surface area by the BET method is used in an ink, the viscosity of the ink increases, and when the specific surface area is low, the coloring power of the ink decreases. Therefore, the specific surface area of ​​the condensed polycyclic organic pigment by the BET method should be 20 to 130 m². 2 The range of / g is preferred, and 50-100m 2 A range of / g is more preferable.

[0097] Examples of inorganic pigments include white inorganic pigments such as titanium dioxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, litsubone, antimony white, and gypsum. Among inorganic pigments, the use of titanium dioxide is particularly preferred. Titanium dioxide is white and is preferred in terms of coloring power, opacity, chemical resistance, and weather resistance. From the viewpoint of printing performance, titanium dioxide that has been treated with silica and / or alumina is preferred.

[0098] Examples of inorganic pigments other than white include carbon black, aluminum particles, mica, bronze powder, chrome vermilion, lead yellow, cadmium yellow, cadmium red, ultramarine, Prussian blue, red iron oxide, yellow iron oxide, iron black, and zircon. Aluminum is available in powder or paste form, but it is preferable to use it in paste form for ease of handling and safety. Whether to use leafing or non-leafing aluminum is selected as appropriate from the standpoint of brightness and density.

[0099] Commercially available carbon black can be used, and there are no particular limitations on the type of carbon black that can be used. Various commercially available types such as oil furnace black, gas furnace black, channel black, and acetylene black, manufactured by contact, furnace, or thermal methods, are acceptable. The particle size of the carbon black is, for example, 5 to 200 nm, preferably 20 to 50 nm. The specific surface area of ​​nitrogen adsorption of the carbon black is, for example, 20 to 500 m². 2 / g, preferably 30-150mg 2 The value is / g. The DBP oil absorption capacity of carbon black is, for example, 20-150 cm³. 3 / 100g, preferably 30-120cm 3 The amount is per 100g. The volatile content of carbon black is, for example, 0.1 to 10.0%. The pH value of carbon black is, for example, 1 to 10, preferably 2 to 9.

[0100] The above commercially available carbon blacks include MA7, 8, 11, 77, 100, 100R, 100S, 220, 230, 600, #650, #750, #40, #44B, #44, #45B, #47, #45, #33, #45L, #47, #50, #52, #2700, #2650, #2600, #200, #2350, #2300, #2200, #1000, #990, #980, #970, #960, #950, #900, #850, #32, #30, #25, #20, #10, #5, CF9, #95, #260 (all manufactured by Mitsubishi Chemical Corporation), "Special "Black 6, 5, 4A, 4, 101, 550, 350, 250, 100", "Printex U, 150T, V, 140V, 140U", "Printex P, L6, L, G, ES23, ES22, A, 95, 90, 85, 80, 75, 60, 55, 45, 40, 35, 300, 30, 3, 25, 200", "Color Black S170, S160, FW2V, FW200, FW2, FW18, FW1" (all manufactured by Orion Engineered Carbons), "Black Pearls 1000M, 800, 880, 4630", "Monarch 1300, 700, 880, 4630", "Regal 330R, 660R, 660, 400R, 415R, 415", "MOGUL E, L (all manufactured by Cabot), Raven 7000, 3500, 5250, 5750, 5000ULTRAII, 1255, 1250, 1190, 1000, 1020, 1035, 1100ULTRA, 1170, 1200 (all manufactured by Colombian Chemicals), SUNBLACK Examples include SB200, 210, 220, 230, 240, 250, 260, 270, 280, 300, 305, 320, 400, 410, 600, 700, 705, 710, 715, 720, 725, 805, 900, 910, 935, 960 (all manufactured by Asahi Carbon Co., Ltd.) and Toka Black #8500, #8500F, #7550SB, #7550F (all manufactured by Tokai Carbon Co., Ltd.).

[0101] <Physical properties of pigments> The pigments used in the liquid ink composition of this embodiment are organic and inorganic pigments commonly used in inks, paints, and recording agents, and have a base adsorption amount of 0.30 μmol / m² per unit surface area of ​​the pigment. 2 It is preferable to use the above-mentioned pigments. The amount of base adsorbed per unit surface area of ​​the pigment is 0.30 μmol / m². 2 By using the above pigments, the dispersion stability of inks using these pigments can be improved. Therefore, it is preferable to use them in combination with ink systems that do not contain vinyl chloride vinyl acetate copolymer, as this improves the problem of reduced pigment dispersibility that occurs in such ink systems. The reason for this is not entirely clear, but it is thought that a large amount of base adsorption per unit surface area of ​​the colorant leads to the adsorption of basic substances or polar parts of the binder resin in the liquid ink composition onto the pigment surface, resulting in excellent dispersibility of the pigment itself. For example, if polyvinyl butyral is not used in the liquid ink composition of this embodiment, the amount of base adsorption per unit surface area of ​​the pigment is 0.30 μmol / m². 2 It is more preferable to use the pigments mentioned above. To obtain the effects described above, the amount of base adsorbed per unit surface area of ​​the pigment should be 0.30 μmol / m². 2 The above is the result, 0.35 μm / m 2 Preferably, it is 0.40 μm / m 2 It is more preferable that the value be greater than or equal to 0.50 μm / m 2 The above is more preferable. On the other hand, there is no particular upper limit to the amount of base adsorption, but 2.00 μmol / m³ is preferable. 2 The following is preferable:

[0102] In this embodiment, the amount of base adsorbed in the pigment can be measured by, for example, adding the pigment to a certain amount of basic solution, allowing the base to be adsorbed onto the pigment, then centrifuging to settle the pigment and collecting the supernatant solution. The amount of base in the supernatant solution is taken as the amount of unadsorbed base, and this is subtracted from the initial amount of base added to calculate the amount of base adsorbed per unit weight of the pigment. The amount of base adsorbed per unit surface area can be calculated by dividing the amount of base adsorbed per unit weight by the nitrogen adsorption specific surface area.

[0103] <Preferred embodiment of the pigment> The pigment used in the liquid ink composition of this embodiment has a base adsorption amount of 0.3 μmol / m² per unit surface area of ​​the pigment, as measured by the method described above. 2 In the above cases, commercially available products or those obtained by conventional manufacturing methods can be used as is. Furthermore, the amount of base adsorption per unit surface area of ​​the pigment is 0.3 μmol / m². 2 The above-mentioned treatment (hereinafter referred to as "base adsorption treatment") may be performed. An example of the above-mentioned base adsorption treatment is a method of treating the surface of the pigment with an iron salt. The iron salt treatment method preferably involves a pigment slurry manufacturing step of adding the pigment to a solvent and stirring to obtain a pigment slurry, a pigment surface treatment step of adding an iron compound and an oxidizing agent to the pigment slurry and stirring to treat the surface of the pigment, and a step of filtering the reaction solution, drying the filtrate, and grinding it. Water and / or an organic solvent can be used as the solvent for the base adsorption treatment. Examples of organic solvents include methanol, ethanol, n-propanol, and i-propanol. Water is particularly preferred from an economic standpoint. The water can be pure water or industrial water, and buffer solutions such as acetate buffer, phosphate buffer, citrate buffer, citrate-phosphate buffer, borate buffer, and tartaric acid buffer may also be used.

[0104] For every 100 parts by mass of solvent used in the base adsorption treatment, the amount of pigment added as a raw material is preferably 1 to 30 parts by mass. If the amount added is too small, productivity is low, and if the amount added is too large, the pigment slurry becomes highly viscous and requires excessive energy for stirring. Therefore, 2 to 20 parts by mass is more preferable, and 3 to 12 parts by mass is particularly preferable.

[0105] Suitable iron compounds include iron sulfate, iron chloride, iron fluoride, iron bromide, iron iodide, iron nitrate, iron phosphate, iron borate, iron carbonate, and iron acetate. From an economic standpoint, iron sulfate, iron chloride, and iron nitrate are preferred. Divalent or trivalent iron can be used. Furthermore, the iron compound may be anhydrous or hydrated.

[0106] The temperature in the pigment slurry manufacturing process is preferably 0°C to 100°C. Similarly, the temperature in the pigment surface treatment process is also preferably 0°C to 100°C. Since the reaction rate of the pigment surface treatment reaction is slow at low temperatures and the decomposition of hydrogen peroxide is accelerated at high temperatures, 10°C to 90°C is more preferable, and 20°C to 80°C is particularly preferable. The reaction time for the pigment surface treatment step is preferably 10 minutes to 2 hours. In the pigment surface treatment process, the pH of the treatment solution is preferably 1 to 7 because the alkaline pH causes iron ions to precipitate.

[0107] Furthermore, hydrogen peroxide, permanganate, hypochlorous acid, chlorous acid, chloric acid, perchloric acid, peroxodisulfate, chromic acid, dichromate, and ozone can be used as oxidizing agents. Among these, hydrogen peroxide diluted with water to a concentration of 20-50% by mass is preferred as an oxidizing agent. The amount of oxidizing agent used should be an amount suitable for the oxidation reaction and will vary depending on the concentration, but for example, 10-100 parts by mass, preferably 20-80 parts by mass, per 100 parts by mass of pigment. The iron compound is preferably added in an amount of 1 to 30% by mass relative to the raw material pigment, and more preferably in an amount of 2 to 15% by mass.

[0108] The iron compound and the oxidizing agent may be added to the pigment slurry simultaneously or separately. If added simultaneously, the iron compound and oxidizing agent may be mixed beforehand. If added separately, the iron compound may be added first, or the oxidizing agent may be added first. The oxidizing agent may also be added dropwise or all at once.

[0109] The pigment obtained by the above process has polar groups formed on its surface, and the amount of base adsorbed per unit surface area of ​​the pigment is 0.3 μmol / m². 2 The above can be achieved. It is presumed that the surface of pigment particles treated in this way will have increased hydrophilicity compared to untreated pigments, resulting in improved wettability to solvents, faster wetting, and superior dispersibility.

[0110] The surface-treated pigment preferably contains 200 ppm or more of iron element per 100 parts by mass of pigment, more preferably 230 ppm or more, more preferably 500 ppm or more, and even more preferably 1000 ppm or more. There is no particular upper limit to the amount of iron element contained in the pigment, but it is preferable that it contains 20,000 ppm or less of iron element per 100 parts by mass, more preferably 18,000 ppm or less, and even more preferably 15,000 ppm or less. More specifically, when an azo pigment is used, it is preferable that the azo pigment contains 200 ppm or more of iron element per 100 parts by mass, more preferably 500 ppm or more, more preferably 1000 ppm or more, and even more preferably 3000 ppm or more. On the other hand, it is preferable that the azo pigment contains 20,000 ppm or less of iron element per 100 parts by mass, more preferably 18,000 ppm or less, and even more preferably 15,000 ppm or less. Furthermore, when carbon black is used, it is preferable that the carbon black contains 200 ppm or more of iron element per 100 parts by mass, preferably 500 ppm or more, more preferably 1000 ppm or more, and even more preferably 3000 ppm or more. On the other hand, it is preferable that the carbon black contains 20000 ppm or less of iron element per 100 parts by mass, more preferably 18000 ppm or less, and even more preferably 15000 ppm or less.

[0111] The element iron is not limited to elemental iron (Fe), but may also be in the form of iron compounds such as iron oxide (FeO, Fe2O3, etc.) or iron hydroxide (Fe(OH)2, Fe(OH)3, etc.). The amount of element iron present in these iron compounds can be measured as the amount of element iron. The amount of iron contained in the pigment can be measured using the PANalytical Epsilon5 energy-dispersive X-ray fluorescence analyzer (manufactured by Spectris Co., Ltd.).

[0112] In the liquid ink composition of this embodiment, the pigment content is preferably 1 to 70% by mass, and more preferably 5 to 60% by mass, relative to the total amount (100% by mass) of the liquid ink composition, which is sufficient to ensure the concentration and coloring power of the liquid ink composition. The solid content mass ratio in the liquid ink composition is preferably 10 to 80% by mass relative to the total amount of solids in the ink composition. Furthermore, the pigment can be used alone or in combination of two or more types. When two or more types are used in combination, the amount of base adsorption per surface area of ​​at least one of the pigments should be 0.30 μmol / m². 2 Anything above that is acceptable. Furthermore, if the liquid ink composition of this embodiment contains polyvinyl butyral, from the viewpoint of the dispersibility of the polyvinyl butyral and its combination with the urethane resin component of this embodiment, the amount of base adsorption on the surface area should be 0.30 μmol / m². 2 Less than a certain amount of pigment can be used.

[0113] (Other resins) The liquid ink composition of this embodiment may contain, as necessary, a urethane resin (I) and other resins that can be used in combination in the ink technology, in addition to a urethane resin component or urethane resin (II). The other resin may be a binder resin or a dispersion resin, but it is preferable to add it as a binder resin. Examples of other resins that can be used in combination include ethylene-vinyl acetate copolymer resins, vinyl acetate resins, polyamide resins, acrylic resins, polyester resins, alkyd resins, rosin-based resins, rosin-modified maleic acid resins, polyvinyl butyral-based resins, cellulose-based resins, ketone resins, cyclized rubbers, petroleum resins, polyurethane resins other than urethane resins (I) and (II), etc. In particular, it is preferable to contain at least one resin selected from polyester resins, acrylic resins, polyamide resins, and rosin-modified maleic acid resins, as this can improve blocking resistance and resolubility. In another embodiment of this model, it is preferable to include at least one resin selected from polyvinyl butyral resin, maleic acid resin, cellulose resin, polyester resin, acrylic resin, and polyamide resin. Furthermore, it is preferable from the viewpoint of reducing environmental impact that the ink composition of this disclosure does not contain chlorine-based resins. These resins can be used individually or in combination of two or more. The content of the combined resins is preferably 0.1 to 25% by mass, and more preferably 2 to 15% by mass, relative to the total mass of the ink.

[0114] <Rosin-modified maleic acid resin> The rosin-modified maleic acid resins mentioned above are alkyd resins obtained by reacting polyhydric alcohols such as glycerin, pentaerythritol, and ethylene glycol with adducts resulting from the Diels-Alder reaction between rosin and maleic acid. The acid value is determined by the ratio of polyhydric alcohols reacted with the rosin-maleic acid adducts and the degree of esterification. In addition to polyhydric alcohols, polybasic acids may also be used to create a structure in which long-chain alkyd resins are bonded to a rosin skeleton.

[0115] Examples of polyhydric alcohols used to react with the rosin and maleic acid adduct include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, trimethylolpropane, glycerin, pentaerythritol, and sorbitol. Polybasic acids used as raw materials for alkyd resins along with these polyhydric alcohols include phthalic anhydride, terephthalic acid, isophthalic acid, adipic acid, maleic acid, itaconic acid, succinic acid, and sebacic acid.

[0116] Furthermore, for example, a compound having a carbon-carbon unsaturated double bond, such as maleic acid, may be used as a raw material for the above-mentioned alkyd resin, and a styrene monomer may be reacted with it to produce a rosin-modified styrene-maleic acid resin, which is also included in rosin-modified maleic acid resin.

[0117] <Polyvinyl butyral resin> The liquid ink composition of this embodiment preferably further contains a polyvinyl butyral resin as a binder resin. This polyvinyl butyral resin has binding and dispersing properties as a binder resin, and since its constituent elements are only carbon atoms, hydrogen atoms, and oxygen atoms, it has the effect of being more environmentally friendly than vinyl chloride-vinyl acetate copolymer resins. Furthermore, when the liquid ink composition contains a pigment, if the pigment is dispersed by kneading with a polyvinyl butyral resin, a suitable group from among the butyral group, polyvinyl alcohol residue, or vinyl acetate residue will be adsorbed onto the pigment, and steric hindrance will occur due to the bulky butyral group. Therefore, using a combination of urethane resin (I) and polyvinyl butyral resin provides better dispersion stability than dispersing the pigment with urethane resin (I) alone. In this embodiment, any known polyvinyl butyral resin can be used without particular limitation. Generally, as the polyvinyl butyral resin, a reaction product obtained by acetalizing polyvinyl alcohol with an aldehyde compound such as butyraldehyde through a known reaction can be used. The polyvinyl butyral resin of this embodiment has the following general formula (4): [ka] (In the above general formula (4), n4 and n5 are independent integers greater than or equal to 1, R 6 It is preferable to have a substructure represented by ). In the above general formula (4), R 6 is preferably a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, more preferably a hydrogen atom or a hydrocarbon group having 1 to 7 carbon atoms, and even more preferably a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms. The hydrocarbon group may be an alkyl group, an alkenyl group, an aryl group, or an aralkyl group, and may be linear, branched, or cyclic. Among these, alkyl groups are preferred. In particular, R 6 A propyl group or an isopropyl group is more preferable. As described above, the polyvinyl butyral resin of the present embodiment is a resin obtained by using polyvinyl alcohol and an aldehyde compound as reaction raw materials. At this time, when the aldehyde compound is represented as R 6 -C(=O)H, R 6 in the general formula (4) is a hydrocarbon group derived from the aldehyde compound used when synthesizing the polyvinyl butyral resin.

[0118] A preferred polyvinyl butyral resin of the present embodiment is preferably a resin having a partial structure represented by the above general formula (4), a partial structure represented by the following general formula (5), and a partial structure represented by the following general formula (6).

Chemical formula

Chemical formula

[0119] In the above general formula (5), R 7 preferably represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. Incidentally, as the R<000009_{003}, for example, a hydrogen atom, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group or a tert-butyl group is more preferable. <00007_{008}Furthermore, when the polyvinyl butyral resin of this embodiment is represented as a resin having a substructure represented by the above general formula (4), a substructure represented by the following general formula (5), and a substructure represented by the following general formula (6), the content of the substructure represented by the above general formula (5) relative to the total amount of the polyvinyl butyral resin is preferably 12% by mass or less, more preferably 8% by mass or less, and even more preferably 5% by mass or less. By setting the content of the substructure represented by the above general formula (5) in the polyvinyl butyral resin to the above range, an ink layer with an excellent balance of fluidity and dispersibility can be obtained.

[0120] The weight-average molecular weight of the polyvinyl butyral resin in this embodiment is preferably 5,000 to 150,000, more preferably 6,000 to 100,000, and even more preferably 7,000 to 50,000. By setting the weight-average molecular weight of the polyvinyl butyral resin within the above range, excellent curability is achieved, and both the strength of the coating film and appropriate flexibility can be obtained. Furthermore, polyvinyl butyral resins with a weight-average molecular weight of 5,000 to 150,000 are readily available, and by using such polyvinyl butyral resins, an ink layer with an excellent balance of fluidity and dispersibility can be obtained.

[0121] The glass transition temperature (hereinafter sometimes referred to as Tg) of the polyvinyl butyral resin in this embodiment is preferably in the range of 50°C to 120°C, more preferably in the range of 55°C to 115°C, and more preferably in the range of 60°C to 110°C. In this invention, the glass transition temperature is obtained by measurement using a differential scanning calorimeter.

[0122] The hydroxyl value of the polyvinyl butyral resin in this embodiment is preferably in the range of 10 to 40 mass / % and more preferably 15 to 30 mass / %. By setting the hydroxyl content of the polyvinyl butyral resin within the above range, an ink layer with an excellent balance of fluidity and dispersibility can be obtained. The amount of hydroxyl groups refers to the amount of the substructure represented by the general formula (6) above relative to the total amount of polyvinyl butyral resin.

[0123] The amount of acetyl groups in the polyvinyl butyral resin is preferably 8% by mass or less, and more preferably 5% by mass or less. By setting the amount of acetyl groups in the polyvinyl butyral resin within the above range, an ink layer with an excellent balance of fluidity and dispersibility can be obtained. The acetyl group refers to the R in the substructure represented by the general formula (5) above. 7 When the substructure is a methyl group, it is called an acetyl group, and the amount of that acetyl group is the content relative to the total amount of polyvinyl butyral resin.

[0124] The content (solids) of polyvinyl butyral resin in the ink composition is preferably 0.1 to 5% by mass, more preferably 0.1 to 4.0% by mass, and most preferably 0.2 to 3.0% by mass, relative to the total resin solids (100% by mass) of the ink composition. Adding 0.1% by mass or more of polyvinyl butyral resin tends to maintain the adhesion and transferability of the ink film, while keeping the total at 5% by mass or less maintains the lamination strength of the ink. Furthermore, the lower limit of the solids mass ratio of polyvinyl butyral resin in the ink composition is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and most preferably 0.3% by mass or more. Furthermore, the upper limit of the solids mass ratio of polyvinyl butyral resin in the ink composition is preferably 45% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less, even more preferably 20% by mass or less, even more preferably 15% by mass or less, and particularly preferably 10% by mass or less.

[0125] <Cellulose resin> Examples of the cellulose-based resins mentioned above include cellulose ester resins such as cellulose acetate propionate, cellulose acetate butyrate, and other cellulose ester resins; nitrocellulose (also known as nitrated cotton); hydroxyalkylcellulose; and carboxyalkylcellulose. The cellulose ester resin preferably has an alkyl group, and examples of such alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, and hexyl groups, and the alkyl group may also have substituents. Of the above cellulose-based resins, cellulose acetate propionate, cellulose acetate butyrate, and nitrocellulose are preferred, with cellulose acetate propionate and cellulose acetate butyrate being particularly preferred. The weight-average molecular weight is preferably 5,000 to 200,000, and more preferably 10,000 to 50,000. Furthermore, a glass transition temperature of 120°C to 180°C is even more preferred. The combined use of the polyurethane resin of the present invention is expected to improve blocking resistance, scratch resistance, and other ink film properties. Nitrocellulose (nitrated cotton) is preferably obtained as a nitrate ester by reacting natural cellulose with nitric acid, in which three hydroxyl groups in the six-membered ring of the anhydrous glucopyranose group in the natural cellulose are replaced with nitrate groups.

[0126] The content (solids) of cellulose-based resin is preferably 0.1 to 5% by mass, more preferably 0.1 to 4.0% by mass, and most preferably 0.2 to 3.0% by mass, relative to the total resin solids (100% by mass) of the ink composition. By setting the content of cellulose-based resin to a range of 0.2 to 3.0% by mass, the effect of anti-blocking properties can be achieved.

[0127] <Chlorine-based resin> The liquid ink composition of this embodiment preferably contains less than 4.5% by mass of chlorine-based resin (or chlorine-containing resin), for example, vinyl chloride-vinyl acetate copolymer resin (solid content), relative to the total liquid ink composition (solid content), more preferably less than 2.5% by mass, even more preferably less than 1.2% by mass, and even more preferably less than 0.5% by mass. Similarly, the content of vinyl chloride vinyl acetate copolymer resin (solids) having hydroxyl groups may be preferably less than 4.5% by mass, more preferably less than 2.5% by mass, even more preferably less than 1.2% by mass, and even more preferably less than 0.5% by mass, relative to the total liquid ink composition (solids). This makes it possible to provide environmentally friendly inks, such as those that are chlorine-free and free of chlorine-based resins. In general, inks currently used in lamination processes widely employ a combination of polyurethane resin and chlorine-based resins such as vinyl chloride-vinyl acetate copolymer resin as a binder resin that achieves both excellent dispersibility and high film properties. In particular, the combination of chlorine-based resin and polyurethane resin is very effective in achieving good printability and various physical properties required for lamination inks (adhesion to substrate, laminate strength, and boil-retort suitability). However, when prioritizing the provision of environmentally friendly inks, it becomes necessary to exclude chlorine-based resins such as vinyl chloride-vinyl acetate copolymer resin. However, if the amount of chlorine-based resin such as vinyl chloride-vinyl acetate copolymer resin used is less than a predetermined amount or is substantially not used, a decrease in extruded laminate strength becomes a problem. However, this disclosure confirms that by combining a specific urethane resin (I) with a urethane bond concentration in the urethane resin component containing said urethane resin (I), or with other binder resins, etc., sufficient extrusion lamination strength can be imparted to the ink even with chlorine-free binder resin compositions, including vinyl chloride-vinyl acetate copolymers. In this embodiment, the liquid ink composition contains at least a binder resin containing a urethane resin component and an organic solvent, wherein the chlorine content of the binder resin is preferably 5% by mass or less, more preferably 1% by mass or less, and even more preferably 0% by mass. This makes it possible to provide environmentally friendly inks, such as those that are chlorine-free and free of chlorine-based resins. The vinyl chloride-vinyl acetate copolymer resin described above is a copolymer of vinyl chloride monomer and vinyl acetate monomer. Therefore, the vinyl chloride-vinyl acetate copolymer resin contains vinyl chloride monomer units and vinyl acetate monomer units. In addition, the vinyl chloride-vinyl acetate copolymer resin may contain monomer units other than vinyl chloride monomer units and vinyl acetate monomer units (other monomer units) as needed. The other monomers are not particularly limited as long as they can be copolymerized with vinyl chloride and vinyl acetate.

[0128] (Additives) The liquid ink composition of this embodiment preferably further contains, if necessary, one or more selected from the group consisting of silica, amide wax, dispersant, defoamer, extender pigment, pigment dispersant, leveling agent, defoamer, wax, dispersant, plasticizer, infrared absorber, ultraviolet absorber, fragrance, and flame retardant. In the liquid ink composition of this embodiment, the content of additives (solids) relative to the total amount of the ink composition is preferably 0.1 to 20.0% by mass.

[0129] The liquid ink composition of this embodiment may further contain a dispersant, if necessary. To stably disperse the aforementioned pigment in an organic solvent, the resin alone can be used for dispersion, but a dispersant can also be used in combination to further stabilize the dispersion of the pigment. As the dispersant, surfactants such as anionic, nonionic, cationic, and amphoteric surfactants can be used. Examples include comb-structured polymer compounds obtained by adding polyester to polyethyleneimine, or alkylamine derivatives of α-olefin maleic acid polymers. Specifically, examples include the Solspers series (ZENECA), Ajisper series (Ajinomoto), and Homogenol series (Kao). The BYK series (BIK Chemie) and EFKA series (EFKA) can also be used as appropriate. From the viewpoint of storage stability of the ink, the dispersant is preferably included in the ink at a concentration of 0.05% by mass or more relative to the total mass of the ink composition, and from the viewpoint of lamination suitability, at a concentration of 5% by mass or less, and more preferably in the range of 0.1 to 2% by mass.

[0130] (Method for manufacturing liquid ink composition) The liquid ink composition of this embodiment can be manufactured by dissolving and / or dispersing resins, pigments, etc., in an organic solvent. Specifically, a pigment dispersion can be manufactured by dispersing pigments in an organic solvent using a polyvinyl butyral resin, and then blending other compounds, resins, etc., into the obtained pigment dispersion to manufacture the ink. The pigment dispersion may be carried out using a urethane resin component, other resins, or a dispersant, but it is preferable to disperse it using a polyvinyl butyral resin, etc.

[0131] The particle size distribution of pigments in a pigment dispersion can be adjusted by appropriately adjusting the size of the grinding media in the disperser, the packing rate of the grinding media, the dispersion processing time, the discharge speed of the pigment dispersion, the viscosity of the pigment dispersion, etc. Commonly used dispersers such as roller mills, ball mills, pebble mills, attritors, and sand mills can be used. If the ink contains air bubbles or unexpectedly large particles, these can degrade the quality of the printed material, so it is preferable to remove them by filtration or other means. Conventional filters can be used.

[0132] The viscosity of the ink composition produced by the above method is preferably in the range of 10 mPa·s or more from the viewpoint of preventing pigment sedimentation and ensuring appropriate dispersion, and 1000 mPa·s or less from the viewpoint of workability during ink production and printing. The above viscosity was measured at 25°C using a Tokimec Type B viscometer. The viscosity of the ink composition can be adjusted by appropriately selecting the type and amount of raw materials used, such as urethane resin (I), urethane resin (II), binder resins other than urethane resin (I) and (II) (e.g., polyvinyl butyral resin), pigments, organic solvents, etc. The viscosity of the ink can also be adjusted by adjusting the particle size and particle size distribution of the pigments in the ink.

[0133] The liquid ink composition of this embodiment has five basic process colors—yellow, red, cyan, black, and white—depending on the type of pigment used, and three extra-process gamut colors—red (orange), grass (green), and purple. Furthermore, transparent yellow, peony, vermilion, brown, gold, silver, pearl, and a nearly transparent medium for adjusting color density (including extender pigments as needed) are prepared as base colors. For boil retort inks, appropriate selections are made considering the migration properties and heat resistance of the pigments.

[0134] (Printed material) The liquid ink composition of this embodiment can be printed to produce printed materials. The printing method can be any known printing method using plates, such as gravure printing or flexographic printing, but gravure printing is particularly preferred. For gravure printing, known types of cylinders, such as engraved or etched types, are used. The layer in which a desired pattern is formed using the liquid ink composition of this embodiment is referred to as the printing layer. The printing layer may be a single layer or there may be multiple printing layers. If there are multiple printing layers, the ink composition used for each printing layer may be the same, or it may be the same composition but with different pigments, or it may be a different composition. In cases where there are multiple printing layers, for example, a printed material may have a first printing layer formed from a colored ink composition, a second white printing layer formed from white ink, and a third white printing layer, in that order. The first printing layer can form a pattern using pigments, and the second white printing layer and the third printing layer, formed from white liquid ink, can be used as backgrounds for the pattern. If the second or third printing layer is an overprint varnish, it does not need to contain coloring agents such as pigments.

[0135] The base ink is diluted with a diluent solvent to a viscosity and concentration suitable for gravure or flexographic printing, and supplied to each printing unit, either alone or in mixtures, for printing.

[0136] (Laminated structure) This disclosure may provide a laminate having a substrate and a printed layer on which a liquid ink composition is printed on at least a portion of the surface of the substrate. The printed layer on the substrate surface may be in direct or indirect contact with the surface of the substrate. Preferred configurations of the laminate in this embodiment include, for example, the following (1) to (4). (1) Base material / adhesive layer / printing layer / base material (2) Base material / adhesive layer / base material / printing layer / adhesive layer / base material (3) Substrate / Adhesive layer / First printing layer / Second printing layer / Substrate (4) Substrate / Adhesive layer / Barrier layer / Printing layer / Adhesive layer / Substrate (5) Base material / printing layer / adhesive layer / base material However, the laminated structure of this embodiment is not limited to (1) to (4) above, and may include additional substrates. If multiple substrates are included, the substrates may be the same or different. The substrate may also be a sealable sealant film or a multilayer film containing a sealant layer made of a heat sealant, and the sealable layer will be referred to as the sealant layer. Furthermore, multiple adhesive layers may have the same composition or different compositions. In addition, an anchor coat layer may be sandwiched between the adhesive layers to improve their adhesive strength.

[0137] The liquid ink composition of this embodiment is useful for a wide variety of films, from general-purpose films to various high-performance films, as a substrate for printing. There are no particular limitations on the usable plastic films, and examples include films made of polyamide resins such as Ny6, nylon 66, and nylon 46; polyester resins such as polyethylene phthalate (PET), polyethylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polybutylene terephthalate, and polybutylene naphthalate; biodegradable resins represented by polyhydroxycarboxylic acids such as polylactic acid, aliphatic polyester resins such as poly(ethylene succinate) and poly(butylene succinate); thermoplastic resins such as polyolefin resins such as polypropylene (PP) and polyethylene, polyimide resins, polyarylate resins, or mixtures thereof; various high-performance films coated with inorganic or organic barrier coating materials on the surface; and laminates thereof. Among these, films made of polyester, polyamide, polyethylene, and polypropylene can be preferably used. These films may be unstretched or stretched films, and their manufacturing method is not limited. They may be multilayer films made by co-extruding the resins of each layer, or they may be multilayer sealant films having a sealant layer on the outermost layer of the multilayer film. The thickness of the base film is also not particularly limited, but is usually in the range of 1 to 500 μm.

[0138] The above-mentioned substrate may be formed from biomass polyolefin. This biomass polyolefin refers to a polyolefin resin using plant-derived olefins as the raw material monomers. These raw material monomers may contain petroleum-derived monomers and do not necessarily contain 100% plant-derived monomers. Commercially available biomass polyolefins can also be used. Examples of commercially available products include Braschem's SGM9450F, SLL118, SLL118 / 21, SLL218, SLL318, SLH118, SLH218, and SLH0820.

[0139] Furthermore, the substrate used in the laminated structure of this embodiment may be a substrate having a vapor-deposited layer made of inorganic material and / or inorganic oxide on the resin film described above. By using a substrate with such a vapor-deposited layer, barrier properties can be imparted to the laminated structure of this embodiment. The vapor-deposited layer can be formed using known inorganic materials or inorganic oxides by known methods, and its composition and formation method are not particularly limited. Furthermore, the laminate may have two or more vapor-deposited films, which may have the same composition or different compositions.

[0140] As the above-mentioned vapor-deposited layer, for example, a vapor-deposited film of an inorganic substance or inorganic oxide such as silicon (Si), aluminum (Al), magnesium (Mg), calcium (Ca), potassium (K), tin (Sn), sodium (Na), boron (B), titanium (Ti), lead (Pb), zirconium (Zr), or yttrium (Y) can be used. Furthermore, vapor-deposited films of inorganic oxides such as silicon oxide and aluminum oxide are transparent.

[0141] The inorganic oxides mentioned above are denoted as MOx (where M represents an inorganic element), such as SiOx and AlOx. The value of x can take values ​​in the following ranges: silicon (Si) 0-2, aluminum (Al) 0-1.5, magnesium (Mg) 0-1, calcium (Ca) 0-1, potassium (K) 0-0.5, tin (Sn) 0-2, sodium (Na) 0-0.5, boron (B) 0-1.5, titanium (Ti) 0-2, lead (Pb) 0-1, zirconium (Zr) 0-2, and yttrium (Y) 0-1.5. In the above, when x=0, it represents a completely inorganic element (pure substance), which is not transparent, and when the value of x is at the upper limit of the range, it indicates that it is completely oxidized. Silicon (Si) and aluminum (Al) are preferably used as the vapor-deposited layer. For silicon (Si), x values ​​in the range of 1.0 to 2.0 can be used, and for aluminum (Al), x values ​​in the range of 0.5 to 1.5 can be used.

[0142] The above-mentioned vapor-deposited layer can be formed on the surface of the substrate or the like by methods such as physical vapor deposition (PVD), including vacuum deposition, sputtering, and ion plating, or chemical vapor deposition (CVD), including plasma chemical vapor deposition, thermochemical vapor deposition, and photochemical vapor deposition.

[0143] The thickness of the above-mentioned vapor-deposited layer is not particularly limited as long as the vapor-deposited layer alone can exhibit a certain gas barrier function. The preferred range of thickness varies depending on the type of metal or metal oxide to be deposited, but is preferably 0.05 to 70 nm, more preferably 0.1 to 70 nm, even more preferably 3 to 70 nm, and even more preferably 5 to 60 nm.

[0144] As the above-mentioned metal-deposited film, VM-CPP film obtained by depositing a metal such as aluminum onto a CPP film, and VM-OPP film obtained by depositing a metal such as aluminum onto an OPP film can be used. Furthermore, as the above-mentioned transparent-deposited film, examples include films obtained by depositing silica or alumina onto OPP film, PET film, nylon film, etc. Films with a coating applied to the deposited layer may also be used for purposes such as protecting the inorganic-deposited layer of silica or alumina.

[0145] Paper can also be used as the substrate. For example, high-quality paper, kraft paper, pure white roll paper, glassine paper, parchment paper, Manila cardboard, white cardboard, coated paper, art paper, imitation paper, thin paper, thick paper, polyethylene coated paper, various synthetic papers, and acid-resistant paper can be used for printing on packaging materials for cosmetics, beverages, pharmaceuticals, toys, and equipment. Furthermore, it is preferable that the printing surface of the substrate be treated with corona discharge to further improve adhesion to the substrate.

[0146] <Lamination Method> The lamination method used when producing the laminated body of this embodiment is not particularly limited and includes methods such as dry lamination, wet lamination, non-solvent lamination, and extrusion lamination. In this case, the layer located between the substrates is referred to as the adhesive layer.

[0147] Examples of adhesives used in the above dry lamination include solvent-type two-component curing adhesives. A "solvent-type" adhesive refers to a form used in the so-called dry lamination method, in which the adhesive is applied to a substrate, heated in an oven or the like to evaporate the organic solvent in the coating, and then bonded to another substrate. It includes a polyisocyanate composition, a polyol composition, and an organic solvent capable of dissolving (diluting) them.

[0148] In the above two-component curable adhesive, considering the construction of a sustainable recycling-oriented society (sustainability) that should continuously develop, it is preferable to use plant-derived raw materials (biomass raw materials) as the raw materials for the above polyisocyanate composition or polyol composition. By appropriately using biomass raw materials, the environmental load can be reduced. Examples of biomass raw materials include castor oil-based polyols such as castor oil, dehydrated castor oil, castor hardened oil which is a hydrogenated product of castor oil, and an adduct of 5 to 50 moles of alkylene oxide to castor oil, aliphatic polybasic acids such as succinic acid, succinic anhydride, glutaric acid, adipic acid, azelaic acid, sebacic acid, itaconic acid, and alkyl esterified products of these acids, dimer acid, and the like.

[0149] As the above adhesive using biomass raw materials, commercially available products can also be used. As commercially available products, adhesives described in the Japan Organic Resources Association, Inc. can be used. For example, Dick Dry BM (manufactured by DIC Corporation), Takenate BM (Mitsui Chemicals, Inc.), and the like can be mentioned.

[0150] The weight of the dried adhesive layer is preferably 0.1 to 10 g / m 2 and more preferably 1 to 6 g / m 2 and even more preferably 2 to 5 g / m 2 In addition, the thickness of the adhesive layer is preferably 0.1 to 10 μm, more preferably 1 to 7 μm, and even more preferably 2 to 5 μm.

[0151] Also, various adhesives can be used as the above adhesive layer, but it is preferable to use a pressure-sensitive adhesive. Examples of the pressure-sensitive adhesive include rubber-based adhesives obtained by dissolving polyisobutylene rubber, butyl rubber, or mixtures thereof in organic solvents such as benzene, toluene, xylene, and hexane, or those obtained by blending tackifiers such as abietic acid rosin ester, terpene-phenol copolymer, and terpene-indene copolymer with these rubber-based adhesives, or acrylic adhesives obtained by dissolving acrylic copolymers having a glass transition temperature of 20°C or lower, such as 2-ethylhexyl acrylate / n-butyl acrylate copolymer and 2-ethylhexyl acrylate / ethyl acrylate / methyl methacrylate copolymer, in organic solvents, and the like.

[0152] When a material having gas barrier properties is used as the above adhesive or the anchor coat agent described later, a laminated film having particularly excellent barrier properties can be obtained. Particularly preferred as an adhesive having excellent gas barrier properties is one that satisfies at least one of the following conditions: the oxygen barrier property of the cured coating film of the adhesive applied at 3 g / m 2 (solid content) is 300 cc / m 2 / day / atm or less, or the water vapor barrier property is 120 g / m 2 / day or less. Commercially available products include the "PASLIM" series such as PASLIM VM001 and PASLIM J350X manufactured by DIC Corporation, and "Maxiseal" manufactured by Mitsubishi Gas Chemical Company.

[0153] In addition, the above adhesive layer can also be formed of a thermoplastic resin, and the forming method can be a conventionally well-known method, for example, a melt extrusion lamination method or a sand lamination method. The liquid ink composition of the present invention is preferably laminated by an extrusion lamination method or a sand lamination method in order to particularly improve the interlayer adhesion strength of the extrusion lamination. Examples of thermoplastic resins that can be used in the adhesive layer include polyethylene resins such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), and high-density polyethylene (HDPE); polypropylene resins such as propylene homopolymers, propylene-α-olefin random copolymers, and propylene-α-olefin block copolymers; norbornene polymers such as ring-opening polymers (COP) of norbornene monomers and norbornene copolymers (COC) obtained by copolymerizing norbornene monomers with olefins such as ethylene, and their hydrogenated products; cyclic polyolefin resins such as vinyl alicyclic hydrocarbon polymers and cyclic conjugated diene polymers; and ethylene Examples include polyethylene elastomers such as vinyl acetate copolymer (EVA) and ethylene-α-olefin copolymer, thermoplastic elastomers such as polypropylene elastomers and butene elastomers; ethylene copolymers such as ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate (EMA) copolymer, ethylene-ethyl acrylate-maleic anhydride copolymer (E-EA-MAH), ethylene-acrylic acid copolymer (EAA), and ethylene-methacrylic acid copolymer (EMAA); and further, ionomers of ethylene-acrylic acid copolymer and ionomers of ethylene-methacrylic acid copolymer. In addition, to improve interlayer adhesion, acid-modified polyolefin resins obtained by modifying the above-mentioned polyolefin resins with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid can also be used. Furthermore, resins obtained by graft polymerization or copolymerization of polyolefin resins with unsaturated carboxylic acids, unsaturated carboxylic acid anhydrides, or ester monomers can also be used. These resins can be used individually or in combination of two or more types. Furthermore, it is also preferable to use a polyethylene-based resin that uses the above-mentioned biomass-derived ethylene as the monomer unit.

[0154] When laminating adhesive layers by extrusion lamination, an anchor coat layer may be provided on the surface of the layer being laminated, formed by applying an anchor coat agent and drying it. Examples of anchor coating agents include any resin with a heat resistance temperature of 135°C or higher, such as polybutadiene resins, urethane resins, polyisocyanate / polyether polyols, polyethyleneimine, vinyl-modified resins, epoxy resins, polyester resins, alkyl titanates, etc., and anchor coating agents obtained by diluting the above adhesives with an organic solvent. Among these, polyethyleneimine-based anchor coating agents and anchor coating agents obtained by diluting the above adhesives with an organic solvent are preferably used. In addition, a silane coupling agent may be used in combination as an additive, and nitrated cotton may also be used in combination to improve heat resistance.

[0155] (packaging material) The packaging material of this embodiment preferably comprises a laminate laminate including a printed layer formed from the liquid ink composition, and more preferably consists of a laminate laminate containing the ink composition. For example, it may be a packaging material in which two laminate laminates are arranged and sealed so that their respective sealant layers are in contact with each other, or a packaging material in which a continuous (one) laminate laminate is folded and arranged so that its sealant layers are in contact with each other and then sealed, or a packaging material in which the laminate laminate and a thermoplastic resin film are arranged and sealed so that the sealant layer of the laminate laminate is in contact with the thermoplastic resin film. The sealing method is not particularly limited and may be heat sealing, ultrasonic sealing, or any known method. The packaging material can be suitably used as a packaging body. Examples of such packaging bodies include food packaging bodies for Western-style confectionery, snacks, bread, Japanese-style confectionery, and seasonings; medical packaging bodies for pharmaceuticals, bandages, syringes, and other medical supplies; and packaging bodies for hygiene products such as cleaning cloths, masks, and brushes. The printed materials, laminates, and packaging materials using these materials of the present invention are recyclable, and the recycled plastic can be used as recycled plastic. [Examples]

[0156] The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way to the examples described below. Hereinafter, "parts" and "%" will be based on mass unless otherwise specified. Furthermore, the weight-average molecular weight (in polystyrene equivalent) measured by GPC (gel permeation chromatography) in this invention was performed using the HLC8220 system manufactured by Tosoh Corporation under the following conditions. Separation column: Four TSKgelGMHHR-N columns manufactured by Tosoh Corporation were used. Column temperature: 40°C. Mobile phase: Tetrahydrofuran manufactured by Wako Pure Chemical Industries, Ltd. Flow rate: 1.0 ml / min. Sample concentration: 1.0 wt%. Sample injection volume: 100 microliters. Detector: Differential refractometer. Viscosity was measured at 25°C using a Tokimec Type B viscometer.

[0157] 1. Measurement or evaluation methods used in the examples and comparative examples. The ink compositions obtained in the examples and comparative examples described below were evaluated using the following test methods.

[0158] (Hydroxyl value) The hydroxyl value is the amount of potassium hydroxide (in mg) required to neutralize the acetic acid bonded to the hydroxyl group when 1 g of the sample is acetylated, and was measured in accordance with JIS K 0070.

[0159] (Acid value) The acid value is the number of milligrams of potassium hydroxide required to neutralize the free fatty acids, resin acids, etc., contained in 1 g of the sample, and was measured in accordance with JIS K 0070.

[0160] (Amine value) The amine value is the number of milligrams of potassium hydroxide equivalent to the amount of hydrochloric acid required to neutralize the amino groups contained in 1 g of the sample, and was measured in accordance with JIS K 0070. Specifically, 0.5 to 2 g of the sample was accurately weighed (sample solid content: Sg). 50 mL of a methanol / methyl ethyl ketone = 60 / 40 (mass ratio) mixed solution was added to the accurately weighed sample and dissolved. Bromophenol blue was added to the resulting solution as an indicator, and the resulting solution was titrated with 0.2 mol / L ethanolic hydrochloric acid solution (titer: f). The endpoint was defined as the point where the color of the solution changed from green to yellow, and the amine value was determined using the following formula based on the titration volume (A mL) at this point. (Formula) Amine value = (A × f × 0.2 × 56.108) / S [mgKOH / g]

[0161] ((Cellophane tape) Adhesion) The viscosity of the ink compositions described in the Examples and Comparative Examples was adjusted with ethyl acetate in a Zahn Cup #3 (manufactured by Rigosha) for 16 seconds (25°C). A print made using OPP film P2161 (20 μm) manufactured by Toyobo Co., Ltd. was prepared on a gravure proofing machine equipped with a gravure plate with a plate depth of 35 μm. After being left for one day, cellophane tape (12 mm wide, manufactured by Nichiban) was applied to the printed surface and rapidly peeled off. The appearance of the printed film was visually judged according to the following criteria. ○: The printed coating did not peel off at all. ○~△: 75~90% of the printed film remained on the film. △: 50-75% of the printed coating remained on the film. ×: Less than 50% of the printed coating remained on the film.

[0162] (Blocking resistance) The viscosity of the ink compositions described in the Examples and Comparative Examples was adjusted with ethyl acetate in a Zahn Cup #3 (manufactured by Rigosha) for 16 seconds (25°C). Using a gravure proofing machine equipped with a 35 μm gravure plate, the films were superimposed so that the printed and unprinted surfaces of a printed material made using OPP film P2161 (20 μm) manufactured by Toyobo Co., Ltd. were in contact, and the viscosity was adjusted to 10 kgf / cm². 2 The samples were subjected to a load and left in a 40°C environment for 12 hours. After removal, the state of ink transfer to the non-printed surface was visually evaluated according to the following three criteria. ○: The amount of ink transferred to the non-printed surface is 0-20%, which is good. △: Less than 50% of the transfer is observed. ×: Less than 80% of the transfer is observed.

[0163] (Extrusion lamination (PEEL) strength) The viscosity of the ink compositions described in the examples and comparative examples was adjusted to 16 seconds (25 °C) with ethyl acetate using a Zahn cup #3 (manufactured by Separation Co., Ltd.), and a gravure proofing machine equipped with a gravure plate with a plate depth of 35 μm was used to produce a printed matter using an OPP film P2161 (20 μm) manufactured by Toyobo Co., Ltd. To this printed matter, a polyethyleneimine-based anchor coating agent was applied at 0.1 g / m 2 After coating, molten polyethylene was laminated to a thickness of 40 μm using an extrusion laminator to obtain a laminated product. After that, the laminated film was cut into a width of 15 mm, and a 90-degree peel test (measurement of PEEL strength) was performed at a pulling speed of 50 mm / min and evaluated according to the following criteria. 〇: The PEEL strength is 1.5 - 2.0 N / 15 mm. ○~△: The PEEL strength is 1.0 - 1.5 N / 15 mm. △: The PEEL strength is 0.5 - 1.0 N / 15 mm. ×: The PEEL strength is less than 0.5 / 15 mm.

[0164] (Mill base fluidity after mincing meat) The viscosities of the liquid ink compositions described in the examples and comparative examples were visually evaluated according to the following criteria. 5: Smooth 4: Slightly sticky 3: Sticky 2: Like stiff fresh cream ]1: Non-flowing (no fluidity)

[0165] (Scratch resistance) Using the liquid ink compositions obtained in the examples and comparative examples, a printed ink laminate was formed using a gravure printing machine. Next, the ink-coated surface of the printed ink laminate was scratched with a fingernail, and the scratch resistance was visually evaluated from the degree of damage to the coating film.

[0166] (Storage (over time) stability (precipitation)) The liquid ink compositions described in the examples and comparative examples were left to stand at 25°C for one week, and then the degree of separation and precipitation was evaluated. <Separation> Appearance Evaluation ○: No separation is observed at all. △: Some separation is observed in the upper layer. As a guideline, the thickness of the separated layer should be 5 mm or less. ×: Clear separation is observed in the upper layer. As a guideline, the thickness of the separated layer should be 5 mm or more. <Sedimentation> Slowly scrape the bottom of the container holding the ink with a spatula. ○: No sedimentation is observed at all. △: A small amount of sediment is visible at the bottom. (A small amount of sediment can be seen on the tip of the spatula.) ×: A large amount of sediment is visible at the bottom. (A lot of sediment can be scraped off with a spatula.)

[0167] 2. Preparation of Liquid Ink Compositions of Examples and Comparative Examples (2-1) Synthesis of urethane resin (I) (2-1.1) Synthesis of urethane resin (Ia) In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, 61.69 parts of neopentyl glycol adipate diol (hydroxyl value: 56.0 mg KOH / g), 9.69 parts of polypropylene glycol (1) (hydroxyl value: 445.0 mg KOH / g), and 22.57 parts of isophorone diisocyanate were charged and reacted at 90°C for 15 hours under a nitrogen stream to produce a urethane prepolymer having isocyanate groups. Then, 50.1 parts of ethyl acetate was added to this to obtain a homogeneous solution of the urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 0.10 parts of dibutylamine, 5.95 parts of isophorone diamine, 101.35 parts of ethyl acetate, and 81.55 parts of isopropyl alcohol, and the mixture was stirred at 45°C for 5 hours to obtain urethane resin solution (Ia). The obtained urethane resin solution (Ia) had a resin solids content of 30% by weight and a urethane bond concentration of 1.38 mmol / g, calculated using the method described above.

[0168] (2-1.2) Synthesis of urethane resin (Ib) In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, 57.87 parts of neopentyl glycol adipate diol (hydroxyl value: 56.0 mg KOH / g), 14.47 parts of polypropylene glycol (2) (hydroxyl value: 280.0 mg KOH / g), and 21.61 parts of isophorone diisocyanate were charged and reacted at 90°C for 15 hours under a nitrogen stream to produce a urethane prepolymer having isocyanate groups. Then, 50.1 parts of ethyl acetate was added to this to obtain a homogeneous solution of the urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 0.10 parts of dibutylamine, 5.95 parts of isophorone diamine, 101.35 parts of ethyl acetate, and 81.55 parts of isopropyl alcohol, and the mixture was stirred at 45°C for 5 hours to obtain urethane resin solution (Ib). The obtained urethane resin solution (Ib) had a resin solids content of 30% by weight and a urethane bond concentration of 1.30 mmol / g, calculated using the method described above.

[0169] (2-1.3) Synthesis of urethane resin (Ic) In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, 59.61 parts of neopentyl glycol adipate diol (hydroxyl value: 56.0 mg KOH / g), 3.79 parts of polypropylene glycol (2) (hydroxyl value: 280.0 mg KOH / g), 11.12 parts of polypropylene glycol (3) (hydroxyl value: 161.0 mg KOH / g), and 19.43 parts of isophorone diisocyanate were charged and reacted at 90°C for 15 hours under a nitrogen stream to produce a urethane prepolymer having isocyanate groups. Then, 50.1 parts of ethyl acetate was added to this to obtain a homogeneous solution of the urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 0.10 parts of dibutylamine, 5.95 parts of isophorone diamine, 101.35 parts of ethyl acetate, and 81.55 parts of isopropyl alcohol, and the mixture was stirred at 45°C for 5 hours to obtain a urethane resin solution (Ic). The obtained urethane resin solution (Ic) had a resin solids content of 30% by weight and a urethane bond concentration of 1.10 mmol / g, calculated using the method described above.

[0170] (2-1.4) Synthesis of urethane resin (Id) In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, 56.36 parts of neopentyl glycol adipate diol (hydroxyl value: 56.0 mg KOH / g), 14.09 parts of polypropylene glycol (4) (hydroxyl value: 111.0 mg KOH / g), 2.01 parts of 1,4-butanediol (hydroxyl value: 1245.0 mg KOH / g), and 21.50 parts of isophorone diisocyanate were charged. The mixture was reacted at 90°C for 15 hours under a nitrogen stream to produce a urethane prepolymer having isocyanate groups. After that, 50.1 parts of ethyl acetate was added to obtain a homogeneous solution of the urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 0.10 parts dibutylamine, 5.95 parts isophoronediamine, 101.35 parts ethyl acetate, and 81.55 parts isopropyl alcohol, and the mixture was stirred at 45°C for 5 hours to obtain a urethane resin solution (Id). The obtained urethane resin solution (Id) had a resin solids content of 30% by weight and a urethane bond concentration of 1.29 mmol / g, calculated using the method described above.

[0171] (2-1.5) Synthesis of urethane resin (Ie) In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, 57.86 parts of neopentyl glycol adipate diol (hydroxyl value: 56.0 mg KOH / g), 4.98 parts of polytetramethylene glycol (1) (hydroxyl value: 491.4 mg KOH / g), 9.48 parts of polytetramethylene glycol (2) (hydroxyl value: 169.4 mg KOH / g), and 21.62 parts of isophorone diisocyanate were charged. The mixture was reacted at 90°C for 15 hours under a nitrogen stream to produce a urethane prepolymer containing isocyanate groups. After that, 50.1 parts of ethyl acetate was added to obtain a homogeneous solution of the urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 0.10 parts dibutylamine, 5.95 parts isophoronediamine, 101.35 parts ethyl acetate, and 81.55 parts isopropyl alcohol, and the mixture was stirred at 45°C for 5 hours to obtain a urethane resin solution (Ie). The obtained urethane resin solution (Ie) had a resin solids content of 30% by weight and a urethane bond concentration of 1.30 mmol / g, calculated using the method described above.

[0172] (2-1.6) Synthesis of urethane resin (If) In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, 59.11 parts of neopentyl glycol adipate diol (hydroxyl value: 56.0 mg KOH / g), 14.78 parts of polycarbonate (1) (hydroxyl value: 216.4 mg KOH / g), and 20.06 parts of isophorone diisocyanate were charged and reacted at 90°C for 15 hours under a nitrogen stream to produce a urethane prepolymer having isocyanate groups. Then, 50.1 parts of ethyl acetate was added to this to obtain a homogeneous solution of the urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 0.10 parts of dibutylamine, 5.95 parts of isophorone diamine, 101.35 parts of ethyl acetate, and 81.55 parts of isopropyl alcohol, and the mixture was stirred at 45°C for 5 hours to obtain a urethane resin solution (If). The obtained urethane resin solution (If) had a resin solids content of 30% by weight and a urethane bond concentration of 1.16 mmol / g, calculated using the method described above.

[0173] (2-1.7) Synthesis of urethane resin (Ig) In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, 59.21 parts of neopentyl glycol adipate diol (hydroxyl value: 56.0 mg KOH / g), 14.80 parts of polypropylene glycol (2) (hydroxyl value: 280.0 mg KOH / g), and 22.15 parts of isophorone diisocyanate were charged and reacted at 90°C for 15 hours under a nitrogen stream to produce a urethane prepolymer having isocyanate groups. Then, 50.1 parts of ethyl acetate was added to this to obtain a homogeneous solution of the urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 0.10 parts of dibutylamine, 3.73 parts of N-(2-aminoethyl)-2-aminoethanol, 101.35 parts of ethyl acetate, and 81.55 parts of isopropyl alcohol, and the mixture was stirred at 45°C for 5 hours to obtain a urethane resin solution (1g). The obtained urethane resin solution (1g) had a resin solids content of 30% by weight, and the urethane bond concentration was 1.33 mmol / g, as calculated using the method described above.

[0174] (2-1.8) Synthesis of urethane resin (Ih) In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, 61.28 parts of neopentyl glycol adipate diol (hydroxyl value: 56.0 mg KOH / g), 15.32 parts of polypropylene glycol (4) (hydroxyl value: 111.0 mg KOH / g), and 17.34 parts of isophorone diisocyanate were charged and reacted at 90°C for 15 hours under a nitrogen stream to produce a urethane prepolymer having isocyanate groups, to which 50.1 parts of ethyl acetate was added. In addition, a homogeneous solution of urethane prepolymer was prepared. Next, the urethane prepolymer solution was added to a mixture consisting of 0.10 parts dibutylamine, 5.95 parts isophorone diamine, 101.35 parts ethyl acetate, and 81.55 parts isopropyl alcohol, and the mixture was stirred at 45°C for 5 hours to obtain a urethane resin solution (Ih). The obtained urethane resin solution (Ih) had a resin solids content of 30% by weight and a urethane bond concentration of 0.91 mmol / g, calculated using the method described above.

[0175] (2-1.9) Synthesis of urethane resin (Ii) In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, 58.96 parts of neopentyl glycol adipate diol (hydroxyl value: 56.0 mg KOH / g), 14.74 parts of polypropylene glycol (4) (hydroxyl value: 111.0 mg KOH / g), 0.37 parts of 1,4-butanediol (hydroxyl value: 1245.0 mg KOH / g), and 19.31 parts of isophorone diisocyanate were charged. The mixture was reacted at 90°C for 15 hours under a nitrogen stream to produce a urethane prepolymer having isocyanate groups. After that, 50.1 parts of ethyl acetate was added to obtain a homogeneous solution of the urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 0.74 parts dibutylamine, 4.41 parts isophoronediamine, 1.47 parts N-(2-aminoethyl)-2-aminoethanol, 101.35 parts ethyl acetate, and 81.55 parts isopropyl alcohol, and the mixture was stirred at 45°C for 5 hours to obtain urethane resin solution (Ii). The obtained urethane resin solution (Ii) had a resin solids content of 30% by weight and a urethane bond concentration of 0.96 mmol / g, calculated using the method described above.

[0176] (2-1.10) Synthesis of urethane resin (Ij) In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, 45.47 parts of neopentyl glycol adipate diol (hydroxyl value: 56.0 mg KOH / g), 19.27 parts of polypropylene glycol (1) (hydroxyl value: 445.0 mg KOH / g), and 29.21 parts of isophorone diisocyanate were charged and reacted at 90°C for 15 hours under a nitrogen stream to produce a urethane prepolymer having isocyanate groups. Then, 50.1 parts of ethyl acetate was added to this to obtain a homogeneous solution of the urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 0.10 parts of dibutylamine, 5.95 parts of isophorone diamine, 101.35 parts of ethyl acetate, and 81.55 parts of isopropyl alcohol, and the mixture was stirred at 45°C for 5 hours to obtain a urethane resin solution (Ij). The obtained urethane resin solution (Ij) had a resin solids content of 30% by weight and a urethane bond concentration of 1.98 mmol / g, calculated using the method described above.

[0177] (2-1.11) Synthesis of urethane resin (Ik) In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, 69.16 parts of neopentyl glycol adipate diol (hydroxyl value: 56.0 mg KOH / g), 5.28 parts of polypropylene glycol (1) (hydroxyl value: 445.0 mg KOH / g), and 19.51 parts of isophorone diisocyanate were charged and reacted at 90°C for 15 hours under a nitrogen stream to produce a urethane prepolymer having isocyanate groups. Then, 50.1 parts of ethyl acetate was added to this to obtain a homogeneous solution of the urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 0.10 parts of dibutylamine, 5.95 parts of isophorone diamine, 101.35 parts of ethyl acetate, and 81.55 parts of isopropyl alcohol, and the mixture was stirred at 45°C for 5 hours to obtain a urethane resin solution (Ik). The obtained urethane resin solution (Ik) had a resin solids content of 30% by weight, and the urethane bond concentration was 1.11 mmol / g, as calculated using the method described above.

[0178] (2-1.12~2-1.17) Synthesis of urethane resin (Il)~(Iq) Using the raw materials listed in Table 1-3, urethane resins (Il) to (Iq) were synthesized in the same manner as urethane resins (Ia) to (Ik). The obtained urethane resin solutions (Il) to (Iq) all had a resin solids content concentration of 30% by weight. For the synthesis of urethane resins (Il) to (Ip), the tolylene diisocyanate used was Cosmonate T-80 manufactured by Mitsui Chemicals, Inc. Furthermore, for the synthesis of urethane resin (Iq), the diphenylmethane diisocyanate used was Millionate NM manufactured by Tosoh Corporation.

[0179] (2-2) Synthesis of urethane resin (II) (2-2.1) Synthesis of urethane resin (II-1) In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, 54.46 parts of neopentyl glycol adipate diol (hydroxyl value: 56.0 mg KOH / g), 9.23 parts of polyethylene glycol (1) (hydroxyl value: 560.0 mg KOH / g), 4.38 parts of polyethylene glycol (2) (hydroxyl value: 280.0 mg KOH / g), and 25.88 parts of isophorone diisocyanate were charged and reacted at 90°C for 15 hours under a nitrogen stream to produce a urethane prepolymer having isocyanate groups. Then, 50.1 parts of ethyl acetate was added to this to obtain a homogeneous solution of the urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 0.10 parts of dibutylamine, 5.95 parts of isophorone diamine, 101.35 parts of ethyl acetate, and 81.55 parts of isopropyl alcohol, and the mixture was stirred at 45°C for 5 hours to obtain urethane resin solution (II-1). The obtained urethane resin solution (II-1) had a resin solids content of 30% by weight, and the urethane bond concentration was 1.68 mmol / g, calculated using the method described above.

[0180] (2-2.2) Synthesis of urethane resin (II-2) In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, 57.97 parts of neopentyl glycol adipate diol (hydroxyl value: 56.0 mg KOH / g), 14.49 parts of polyethylene glycol (2) (hydroxyl value: 280.0 mg KOH / g), and 21.49 parts of isophorone diisocyanate were charged and reacted at 90°C for 15 hours under a nitrogen stream to produce a urethane prepolymer having isocyanate groups. Then, 50.1 parts of ethyl acetate was added to this to obtain a homogeneous solution of the urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 0.10 parts of dibutylamine, 5.94 parts of isophorone diamine, 101.35 parts of ethyl acetate, and 81.55 parts of isopropyl alcohol, and the mixture was stirred at 45°C for 5 hours to obtain urethane resin solution (II-2). The obtained urethane resin solution (II-2) had a resin solids content of 30% by weight and a urethane bond concentration of 1.30 mmol / g, calculated using the method described above.

[0181] (2-2.3) Synthesis of urethane resin (II-3) In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, 351.5 parts of hydrogenated ketone-aldehyde resin (TEGO® Varipuls SK, number average molecular weight 800, hydroxyl value 325 mg KOH / g, manufactured by EVONIK), 48.5 parts of isophorone diisocyanate, and 400 parts of ethyl acetate were charged. The mixture was reacted under a nitrogen stream at 90°C for 6 hours to obtain a urethane resin (II-3) with a solid content of 50% and a number average molecular weight of 1700. The urethane bond concentration of urethane resin (II-3) was 1.26 mmol / g, calculated using the method described above.

[0182] [Table 1-1]

[0183] [Table 1-2]

[0184] [Table 1-3]

[0185] As shown in the composition ratios in Tables 1-1, 1-2, and 1-3 above, urethane resins (Ia) to (Iq) and urethane resins (II-1) to (II-3) were synthesized. Then, the urethane bond concentration and number-average molecular weight (Mn) were measured using the method described above. The results are shown in Tables 1-1, 1-2, and 1-3.

[0186] Furthermore, the raw materials used in the examples and comparative examples in Tables 1-1, 1-2, and 1-3 above are shown below. [Polypropylene glycol] • Polypropylene glycol (1): "Uniol D-250" manufactured by NOF Corporation (number average molecular weight 250) • Polypropylene glycol (2): "Uniol D-400G" manufactured by NOF Corporation (number average molecular weight 400) • Polypropylene glycol (3): "Uniol D-700" manufactured by NOF Corporation (number average molecular weight 700) • Polypropylene glycol (4): "Uniol D-1000" manufactured by NOF Corporation (number average molecular weight 1000)

[0187] [Tetramethylene glycol] • Polytetramethylene glycol (1): Mitsubishi Chemical Corporation's "PTMG250" (number average molecular weight 225) • Polytetramethylene glycol (2): Mitsubishi Chemical Corporation's "PTMG650" (number average molecular weight 650) [Polycarbonate] • Polycarbonate (1): "ETERNACOLL PH-50" manufactured by UBE Corporation (number average molecular weight 500) [Polyethylene glycol] • Polyethylene glycol (1): NOF Corporation's "PEG #200" (number average molecular weight 200) • Polyethylene glycol (2): NOF Corporation's "PEG #400" (number average molecular weight 400)

[0188] (2-2) Preparation of liquid ink composition <Example 1> A mixture of 15 parts by mass of a polyvinyl butyral resin-containing solution (10% solids by mass of polyvinyl butyral resin), 10 parts by mass of a phthalocyanine blue pigment (FASTGEN Blue LA5380, manufactured by DIC Corporation), and 35 parts by mass of ethyl acetate was kneaded, and 30.0 parts by mass (30% solids by mass) of the urethane resin (Ia) obtained above and 10 parts by mass of propyl acetate were added to prepare a liquid ink composition, blue printing ink composition (1) (hereinafter also referred to as composition (1)). The amount of base adsorption per unit surface area of ​​the phthalocyanine blue pigment (FASTGEN Blue LA5380, manufactured by DIC Corporation) was 0.0 μmol / m². 2 That was it.

[0189] <Examples 2-34> Blue printing ink compositions (2) to (34) (hereinafter also referred to as compositions (2) to (34)) were prepared as liquid ink compositions in the same manner as in Example 1, using the compositions and composition ratios shown in Tables 2-1, 2-2, and 2-3 below. The compositions (1) to (34) obtained in Examples 1 to 34 above were subjected to the various evaluations described above.

[0190] <Comparative Examples 1-6> Comparative blue printing ink compositions (1) to (6) (hereinafter also referred to as comparative compositions (1) to (6)) were prepared as liquid ink compositions in the same manner as in Example 1, using the compositions and composition ratios shown in Tables 2-1 and 2-2 below. The comparative compositions (1) to (6) obtained in Comparative Examples 1 to 6 above were subjected to the various evaluations described above.

[0191] [Table 2-1]

[0192] [Table 2-2]

[0193] [Table 2-3] In Tables 2-1 to 2-3 above, the easily dispersible pigment Blue 15:3 was obtained using the following method. 373.1 parts of CI Pigment Blue 15:3 (manufactured by DIC Corporation) wet cake (150 parts pigment) and 500 parts of deionized water were placed in a 2L stainless steel cup and stirred for 15 minutes using a Homodisper 2.5 type (manufactured by Primix Corporation) at a rotation speed of 500 rpm. The CI Pigment Blue 15:3 slurry was transferred to a 5L stainless steel cup, 2127 parts of deionized water were added, and while stirring with a stainless steel anchor blade at a rotation speed of 150 rpm, 3.8 parts of iron(II) sulfate heptahydrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were added and dissolved, and the temperature was raised to 60°C. Subsequently, 54 parts of 35% hydrogen peroxide solution (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were added and stirred for 2 hours. Next, the slurry was filtered through Nutsch filtration and washed with 12 L of 70°C hot water. The filtrate was then air-dried in a WFO-500 forced-air constant-temperature dryer (manufactured by Tokyo Rikakikai Co., Ltd.) at 98°C for 18 hours. The resulting pigment mass was pulverized to obtain 150 parts of copper phthalocyanine pigment (PB15:3). The amount of iron in the pigment was 3530 ppm. The amount of base adsorbed per unit surface area of ​​the pigment was 0.57 μmol / m². 2 That was it. In this embodiment, the amount of iron element contained in the pigment was measured using an energy-dispersive X-ray fluorescence analyzer PANalytical Epsilon5 (manufactured by Spectris Co., Ltd.). In this embodiment, the amount of base adsorbed per unit surface area of ​​the pigment was measured using the following method. Approximately 100 mg of pigment was weighed into a 50 mL polyethylene wide-mouth bottle along with 15 mL of adsorption base solution, and the mixture was stirred using a paint shaker (manufactured by Toyo Seiki Seisakusho Co., Ltd.) at 750 cpm for 15 minutes. Subsequently, the pigment was centrifuged using a refrigerated high-speed centrifuge H-2000B (manufactured by Kokusan Co., Ltd.) at 3500 G for 20 minutes to allow it to settle, and 10 mL of the supernatant solution was collected. This supernatant solution was diluted with 15 mL of n-propyl acetate (manufactured by Kanto Chemical Co., Ltd.), and the amount of unadsorbed base present in the supernatant solution was measured by potentiometric titration with a titration acid solution using an automatic titrator COM-A19 (manufactured by HIRANUMA Co., Ltd.). The amount of base adsorbed per unit weight of pigment was calculated by subtracting the amount of unadsorbed base from the amount of base added. The amount of base adsorbed per unit surface area of ​​pigment was then calculated by dividing the amount of base adsorbed per unit weight by the nitrogen adsorption specific surface area. The adsorption base solution was prepared by precisely diluting a 0.1 mol / L tetra-n-butylammonium hydroxide solution (N / 10) (benzene-methanol solution) (manufactured by Kanto Chemical Co., Ltd.), which has a known factor value, to 1 / 100th with n-propyl acetate (manufactured by Kanto Chemical Co., Ltd.). Furthermore, as the titration acid solution, approximately 95 mg of p-toluenesulfonic acid monohydrate (manufactured by Kanto Chemical Co., Ltd.) was dissolved in 500 mL of n-propyl acetate (manufactured by Kanto Chemical Co., Ltd.), and the concentration was titrated with the aforementioned adsorption base solution before use.

[0194] From the experimental results in Tables 2-1, 2-2, and 2-3 above, it was confirmed that the ink compositions of Examples 1 to 34 all formed ink layers with superior blocking resistance, adhesion, and lamination suitability compared to the comparative example ink compositions. Furthermore, the evaluation results for the separation of the storage (over time) stability, which is an indicator of the pigment dispersibility of the ink compositions of Examples 1 to 34, were either "no separation observed at all" or "a separation layer with a thickness of 5 mm or less was observed slightly above the main layer." The evaluation results for the precipitation of the ink compositions of Examples 1 to 34 were also either "no precipitation observed at all" or "a small amount of precipitation observed at the bottom (a small amount of precipitation was confirmed on the tip of the spatula)." The mill base fluidity of the ink compositions of Examples 1 to 34 after mixing was either "5" or "4." Furthermore, scratch resistance test results confirmed that the ink layers formed from the ink compositions of Examples 1 to 34 were either free of scratches or only slightly scratched. This is thought to be due to the high concentration of urethane bonding in the ink compositions of Examples 1 to 34. Therefore, it was confirmed that all of the ink compositions of Examples 1 to 34 are compositions that can form an ink layer with an excellent balance of scratch resistance, pigment dispersibility, fluidity, and storage (over time) stability.

[0195] This application claims priority to Japanese Patent Application No. 2023-122879, filed on 27 July 2023, the contents of which are incorporated herein by reference.

Claims

1. A liquid ink composition containing at least a urethane resin component and an organic solvent, The urethane resin component contains only urethane resin (I) whose reaction raw material (1) is a polycarbonate or a polyoxyalkylene compound having 3 to 4 carbon atoms as a structural unit and a first isocyanate compound, or contains urethane resin (II) other than urethane resin (I) and urethane resin (I). The amount of chlorine-containing resin contained in the liquid ink composition is less than 4.5% by mass of the total liquid ink composition (solids). The liquid ink composition contains less than 10% by mass of water relative to its total amount. The content of the urethane resin (I) is 30 to 100% by mass relative to the total resin solids content of the liquid ink composition. The urethane bond concentration of the urethane resin (I) is in the range of 0.4 mmol / g or more and 2.3 mmol / g or less, and the urethane bond concentration of the urethane resin (II) is in the range of 0.98 mmol / g or more and less than 2.0 mmol / g. A liquid ink composition in which the total urethane bond concentration of the urethane resin component is 0.98 mmol / g or more and 2.0 mmol / g or less.

2. The liquid ink composition according to claim 1, wherein the content of the urethane resin (II) is 65% by mass or less with respect to the total resin solids content (100% by mass) of the liquid ink composition.

3. The liquid ink composition according to claim 1, wherein the urethane resin (I) is a urethane urea resin.

4. The liquid ink composition according to claim 1, wherein the urethane bond concentration of the urethane resin (I) is 0.98 mmol / g or more and 2.3 mmol / g or less.

5. The liquid ink composition according to claim 1, further containing a urethane resin (II) other than the urethane resin (I).

6. The liquid ink composition according to claim 5, wherein the urethane bond concentration of at least one of the urethane resin (I) or the urethane resin (II) is 0.98 mmol / g or more and less than 2.0 mmol / g.

7. The liquid ink composition according to claim 5, wherein at least one of the urethane resin (I) or the urethane resin (II) contains a polyester polyol as a reaction raw material.

8. The liquid ink composition according to claim 5, wherein the total amount of urethane resin (I) and urethane resin (II) among the resin components contained in the liquid ink composition is 30 to 100% by mass with respect to the total resin solids content of the liquid ink composition.

9. The liquid ink composition according to claim 1, comprising at least one resin selected from polyvinyl butyral resin, maleic acid resin, cellulose resin, polyester resin, acrylic resin, and polyamide resin.

10. The present invention further contains a pigment, wherein the amount of base adsorbed per unit surface area of ​​the pigment is 0.30 μmol / m². ２ The liquid ink composition according to claim 1.

11. The liquid ink composition according to claim 1, further comprising a pigment, wherein the pigment contains 200 ppm or more of iron element per 100 parts by mass of the pigment.

12. A printed article obtained by printing the ink composition according to any one of claims 1 to 11 onto a substrate.

13. A laminate or packaging comprising the printed material described in claim 12.

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