Liquid ink composition, printed matter, multilayer body or package

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

Liquid ink composition, printed matter, laminate or packaging

[0001] The present disclosure relates to a liquid ink composition, a printed matter, a laminate or a package.

[0002] Gravure inks and flexographic inks are widely used to impart aesthetic and functional properties to printed substrates. When printed substrates are used as packaging materials, particularly food packaging, they are typically laminated. In this case, various printing methods are used, such as front printing (printing from the front side of a material such as a plastic film) or reverse printing (reversing the printing order of the printed image or colors), depending on the type of contents or intended use. Conventionally, inks used in such laminating processes have commonly utilized a combination of polyurethane resin and vinyl chloride-vinyl acetate copolymer resin as a binder resin, offering both excellent dispersibility and high film properties. This combination of polyurethane resin and vinyl chloride-vinyl acetate copolymer resin is an essential ink ingredient for achieving good printability and the physical properties required for laminating inks (adhesion to substrates, lamination strength, and boil-retort suitability). For example, Patent Document 1 discloses a laminate ink composition for flexible packaging, the main components of which are a colorant, an organic solvent other than an aromatic organic solvent, and a binder resin containing, as essential components, a polypropylene glycol-containing polyurethane resin and a vinyl chloride-vinyl acetate copolymer resin having a hydroxyl group.

[0003] However, in response to the trend toward building a recycling-oriented society that reduces substances that may have adverse effects on humans or the environment, as exemplified by the Sustainable Development Goals, legal regulations surrounding food packaging are becoming stricter worldwide. In particular, in recent years, stricter regulations on packaging ingredients and their migration into food have been required. Furthermore, the movement toward eliminating plastics is accelerating, increasing demand for recyclable packaging. Therefore, in the development of gravure ink products, it has become necessary to design ink and packaging components using materials that are safe for humans and the environment. In particular, vinyl chloride-vinyl acetate copolymers are of concern as substances that hinder packaging recycling for the following reasons: (a) Chlorinated resins such as vinyl chloride can corrode equipment or piping by releasing hydrogen chloride during the thermal decomposition process of recycling, generating hydrochloric acid. (b) In thermal recycling, which reuses energy generated from waste incineration, the incineration of chlorinated resins can release environmental hormones such as dioxins. Therefore, the development of environmentally friendly inks, such as those that are chlorine-free, is required. 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 mass% or less and containing a urethane resin (A) and a resin (B).

[0004] JP 2022-096163 A JP 2022-139294 A

[0005]

[0005] The above-mentioned Patent Documents 1 and 2 discuss blocking resistance, film adhesion, and lamination properties. However, they do not mention the problem that if the printed surface formed from these ink compositions, which displays information about contents or a pattern evoking aesthetic appeal, is damaged, the information or pattern will be lost. Therefore, an object of the present disclosure is to provide a liquid ink composition capable of forming an ink layer that has an excellent balance of blocking resistance, adhesion, lamination suitability, scratch resistance, pigment dispersibility, fluidity, and storage (aging) stability.

[0006]

[0006] Therefore, the present inventors conducted extensive research to solve the above problems and found that by using a specific urethane resin (I) and controlling the urethane bond concentration, it is possible to form an ink layer that has an excellent balance of blocking resistance, adhesion, lamination suitability, scratch resistance, pigment dispersibility, fluidity, and storage (aging) stability, and have completed the present invention described in any of (1) to (13) below.

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

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

[0009] [3] A liquid ink composition according to [1] or [2], which contains 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 according to any one of the above [1] to [3], comprising at least a binder resin containing a urethane resin component and the organic solvent, wherein the proportion of the solid content of the entire urethane resin component relative to the total solid content of the binder resin component is 50 mass % or more.

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

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

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

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

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

[0016]

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

[0017]

[11] A composition further comprising a pigment, wherein the pigment has a base adsorption amount per surface area of ​​the pigment of 0.30 μmol / m ２ The liquid ink composition according to any one of the above [1] to

[10] .

[0018]

[12] The 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 the pigment.

[0019]

[13] A printed matter obtained by printing the ink composition according to any one of [1] to

[12] above onto a substrate.

[0020] According to the present disclosure, it is possible to provide a liquid ink composition capable of forming an ink layer that has an excellent balance of blocking resistance, adhesion, lamination suitability, scratch resistance, pigment dispersibility, and fluidity and storage (aging) stability.

[0021] Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail, but the present invention is not limited to the following description and can be practiced with various modifications within the scope of the gist. Furthermore, in the present embodiment, A (numerical value) to B (numerical value) mean A or more and B or less.

[0022] [Definitions] As used herein, the term "liquid ink composition" refers to a liquid printing ink, such as gravure ink or flexographic ink, that is applied to a printing method using a printing plate, and preferably gravure ink or flexographic ink. Furthermore, in the following description, "ink" always refers to "printing ink." As used herein, "parts" always refer to "parts by mass." "Total amount of ink" refers to the total amount of ink, including all volatile components such as solvents. "(Ink or resin) solids (total amount)" refers to the total amount of nonvolatile components only, excluding volatile components. As used herein, "reactive raw materials" refer to compounds that are used to obtain a target compound through a chemical reaction, such as synthesis or decomposition, and that partially constitute the chemical structure of the target compound, excluding catalysts and solvents. In particular, as used herein, "reactive raw materials" refer to precursors for obtaining the target urethane resin (I) or urethane resin (II) through a chemical reaction, and include various isocyanate compounds, various polyols, and amine compounds added as needed (for example, amine compounds such as the chain extenders described below). For example, the "content of the first isocyanate compound relative to the reaction raw material (1) (100% by mass)" represents the proportion relative to 100% by mass of the total of the first isocyanate compound and all polyol components (the total amount of polycarbonate or polyoxyalkylene compound having a structural unit of 3 to 4 carbon atoms, optionally blended polyester polyol, optionally blended aromatic polyol, optionally blended polyether polyol, and optionally blended concomitant polyol). In this specification, the term "structural unit" refers to a (repeating) unit of a chemical structure formed during reaction or polymerization; in other words, in a product compound formed by reaction or polymerization, it refers to a partial structure other than the structure of the chemical bond involved in the reaction or polymerization, i.e., a so-called residue.

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

[0024] [Liquid Ink Composition (hereinafter also simply referred to as "Ink Composition")] The liquid ink composition of the present 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 whose reaction raw materials (1) are a polycarbonate or a polyoxyalkylene compound having a structural unit of 3 to 4 carbon atoms and a first isocyanate compound. The urethane bond concentration of the entire urethane resin component is 0.98 mmol / g or greater. This allows for the provision of an ink composition with excellent blocking resistance, adhesion, boiling / laminating suitability, scratch resistance, pigment dispersibility, fluidity, and storage (aging) stability. Morphologically, the liquid ink composition of this embodiment contains a binder resin, an organic solvent, and, optionally, one or more components selected from the group consisting of pigments and additives. The binder resin contains a urethane resin component as an essential component, and the urethane resin component contains at least a urethane resin (I) whose reaction raw materials (1) are a polycarbonate or a polyoxyalkylene compound having a structural unit of 3 to 4 carbon atoms and a first isocyanate compound. In this specification, the term "urethane resin component" is a general term for resins having a number-average molecular weight of 1,000 or more and containing urethane bonds, and contains at least the urethane resin (I). The "urethane resin component" may, if necessary, further contain a urethane resin (II) other than the urethane resin (I). The urethane resin (II) other than the urethane resin (I) has a chemical structure different from that of the urethane resin (I). In this specification, the term "binder resin" refers to a binding resin contained in the ink or ink composition. The binder resin may be dissolved in a solvent or in an emulsion state. Therefore, the binder resin essentially contains a urethane resin component, and may contain binder resins other than the urethane resin component (hereinafter referred to as other resins) as needed.For ease of explanation, the "polyester polyol" and "polyether polyol" that can be contained as components of the reaction raw material (2) of the urethane resin (II) are referred to as "polyester polyol (II)" and "polyether polyol (II)." Similarly, the "isocyanate compound" that is a component of the reaction raw material (2) of the urethane resin (II) is referred to as the "second isocyanate compound," and the "isocyanate compound" that is a component of the 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 (solid content) is preferably 5 to 95 mass % relative to the total solid content of the liquid ink composition, more preferably 15 to 80 mass %, even more preferably 20 to 60 mass %, and even more preferably 30 to 60 mass %. By making the content of the urethane resin component (solid content) 30 mass % or more, better polyethylene extrusion lamination strength is exhibited when printed on OPP film.

[0026] In the liquid ink composition of this embodiment, the content of the binder resin (solid content) 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 solid content of the liquid ink composition. By making the content of the binder resin (solid content) 20% by mass or more, better pigment dispersion stability and coating film properties are exhibited. On the other hand, by making the content of the binder resin (solid content) less than 20% by mass, printing color density is exhibited.

[0027] In the liquid ink composition of this embodiment, the proportion of the urethane resin component (solid content) relative to the total solid content of the binder resin (solid content) is preferably 30 to 100 mass %, more preferably 40 to 90 mass %, and even more preferably 50 to 80 mass %. By making the proportion of the urethane resin component (solid content) 50 mass % or more, better polyethylene extrusion lamination strength is exhibited 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 necessary, which allows the formation of an ink layer with superior blocking resistance, adhesion, lamination suitability, scratch resistance, pigment dispersibility, fluidity, and storage (aging) stability.

[0029]

[0033] The liquid ink composition of this embodiment may also contain, if necessary, a binder resin (another resin) other than the urethane resin component. This allows for the formation of an ink layer with superior blocking resistance, adhesion, lamination suitability, scratch resistance, pigment dispersibility, fluidity, and storage (aging) stability. The liquid ink composition of this embodiment may also contain, if necessary, one or more selected from the group consisting of pigments and additives.

[0030] The essential components of the liquid ink composition of the present disclosure, namely, the urethane resin component, urethane resin (I), and organic solvent, as well as the optional components, namely, the urethane resin (II), other resins serving as binder resins other than the urethane resin component, pigments, and additives, will be described in detail below.

[0031] (Urethane Resin Component) The liquid ink composition of the present disclosure contains a urethane resin component, which is a resin having a number average molecular weight of 1,000 or more and has a urethane bond, and the urethane resin component essentially contains a urethane resin (I). The urethane resin component functions as a binder resin to improve the adhesion of the ink, and can also function as a pigment dispersing resin. The urethane resin component may contain a urethane resin (II) other than the urethane resin (I). By using a specific urethane resin (I) in combination with a urethane resin (II) other than the urethane resin (I), an ink layer can be formed that is superior in blocking resistance, adhesion, lamination suitability, scratch resistance, pigment dispersibility, fluidity, and storage (aging) stability.

[0032] <Urethane Bond Concentration> In this embodiment, the lower limit of the urethane bond concentration of the entire urethane resin component is 0.98 mmol / g or more, more preferably 1.05 mmol / g or more, even more preferably 1.10 mmol / g or more, still 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 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, still 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, still more preferably 2.3 mmol / g or less, and particularly preferably 1.8 mmol / g or less. In this embodiment, the preferred range of the urethane bond concentration of the entire urethane resin component is 0.98 mmol / g or more and 5.0 mmol / g or less, 1.05 mmol / g or more and 4.0 mmol / g or less, 1.10 mmol / g or more and 3.0 mmol / g or less, or 1.10 mmol / g or more and 2.0 mmol / g or less. The upper and lower limits can be arbitrarily combined. A urethane bond concentration of 0.98 mmol / g or more is preferred from the viewpoint of polyethylene extrusion lamination strength when printed on an OPP film. On the other hand, a urethane bond concentration of 2.0 mmol / g or less is preferred from the viewpoints of urethane resin raw material cost, ink viscosity, and flexibility of the ink coating on the film (adaptability to film deformation).

[0033] The urethane bond concentration in this specification is calculated using the following mathematical formula (a). More specifically, the calculation method for the urethane bond concentration will be explained below using the example of a case where the urethane resin component of this embodiment includes urethane resin (I), urethane resin (II), ... urethane resin (k) (k is a natural number), i.e., a case where the urethane resin component is composed of k types of urethane resins. In this case, it is assumed that the polyol components (including at least polycarbonate or a polyoxyalkylene compound having a structural unit of 3 to 4 carbon atoms) contained in the reaction raw material (1) of urethane resin (I) are w types (w is a natural number), the polyol components (including at least one of polyester polyol or polyether polyol) contained in the reaction raw material (2) of urethane resin (II) are v types (v is a natural number), ... the polyol components (including at least polyester polyol or polyether polyol) contained in the reaction raw material (k) of urethane resin (k) are x types (x is a natural number). [Mathematical formula (a)]: Urethane bond concentration = [{(W ｉ１ ×OH ｉ１ +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 OH: mass of the first polyol component contained in the reaction raw material (1) of the urethane resin (I) ｉ１ W: hydroxyl value of the first polyol component contained in the reaction raw material (1) of the urethane resin (I) ｉ２ OH: mass of the second polyol component contained in the reaction raw material (1) ｉ２ W: hydroxyl value of the second polyol component contained in the reaction raw material (1)ｉｗ OH: mass of the wth polyol component contained in the reaction raw material (1) ｉｗ W: hydroxyl value of the wth polyol component contained in the reaction raw material (1) ｉｉ１ OH: mass of the first polyol component contained in the reaction raw material (2) of the urethane resin (II) ｉｉ１ W: hydroxyl value of the first polyol component contained in the reaction raw material (2) of the urethane resin (II) ｉｉ２ OH: mass of the second polyol component contained in the reaction raw material (2) ｉｉ２ W: hydroxyl value of the second polyol component contained in the reaction raw material (2) ｉｉｖ OH: mass of the vth polyol component contained in the reaction raw material (2) ｉｉｖ W: hydroxyl value of the vth polyol component contained in the reaction raw material (2) ｋ１ OH: mass of the first polyol component contained in the reaction raw material (k) of the urethane resin (k) ｋ１ W: hydroxyl value of the first polyol component contained in the reaction raw material (k) of the urethane resin (k) ｋ２ OH: mass of the second polyol component contained in the reaction raw material (k) ｋ２ W: hydroxyl value of the second polyol component contained in the reaction raw material (k) ｋｘ OH: mass of the xth polyol component contained in the reaction raw material (k) ｋｘwhere S is the hydroxyl value of the xth polyol component contained in the reactive raw material (k), and S is the mass of the total solids of the urethane resin component. In the above formula (a), when the urethane resin component is composed of one or more urethane resins and one or more polyol components are used as the reactive raw materials for the one or more urethane resins, the calculation is performed using polyol component (i1) to polyol component (iw), polyol component (ii1) to polyol component (iiv), ... polyol component (k1) to polyol component (kx). That is, in the above formula (a), the urethane bond concentration is calculated by multiplying the sum of the products of the masses of the polyol components in all the polyol components and the hydroxyl values ​​of those polyol components by 1,000, as the numerator, and by multiplying 56,100 by the mass of the total solids of the urethane resin component as the denominator. The urethane bond concentration in this specification can be measured as follows. The urethane resin is obtained by solvent extraction from the liquid ink composition of this embodiment. The urethane bond concentration can be calculated by subjecting the solvent-extracted urethane resin sample to the following two analytical methods. Analytical Method 1: NMR analysis is performed, and the urethane bond concentration is calculated from the integrated value of the peak derived from the urethane bond. Analytical Method 2: NMR, GPC, and mass spectrometry are performed to obtain information on the molecular weight, chemical structure, and content ratio of the isocyanate compound, polyol component, amine compound, and other components that constitute the urethane resin. The urethane bond concentration is calculated from this compositional information. Furthermore, the urethane resin component as a whole in this embodiment preferably contains a polyester polyol as a reactive raw material. Specifically, either the urethane resin (I) or the urethane resin (II) may contain a polyester polyol as a reactive raw material, or both the urethane resin (I) and the urethane resin (II) may contain a polyester polyol as a reactive raw material. Similarly, the urethane resin component as a whole in this embodiment preferably contains a polyether polyol as a reactive raw material.Specifically, either the urethane resin (I) or the urethane resin (II) may contain a polyether polyol as a reaction raw material, or both the urethane resin (I) and the urethane resin (II) may contain a polyether polyol as a reaction raw material.

[0034] (Urethane Resin (I)) The liquid ink composition of this embodiment contains, as an essential component, at least a urethane resin (I) in which polycarbonate or a polyoxyalkylene compound having structural units of 3 to 4 carbon atoms and a first isocyanate compound are used as reaction raw materials (1). In other words, the urethane resin (I) in this embodiment has a structure in which structural units derived from polycarbonate or a polyoxyalkylene compound having structural units of 3 to 4 carbon atoms are chemically bonded directly or indirectly to structural units derived from the first isocyanate compound. The reaction raw material (1) may further contain a polyester polyol and / or an aromatic polyol described below. That is, the liquid ink composition of this embodiment may contain a urethane resin (I) in which polycarbonate or a polyoxyalkylene compound having structural units of 3 to 4 carbon atoms, a polyester polyol, an aromatic polyol, and a first isocyanate compound are used as reaction raw materials (1). In other words, one preferred urethane resin (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 chemically bonded directly or indirectly. The urethane resin (I) is not particularly limited as long as it is a resin having a urethane bond obtained by reacting a polyol with an isocyanate. Furthermore, the urethane resin (I) functions as a binder resin to improve ink adhesion and can also function as a pigment dispersing resin. Furthermore, the urethane resin (I) is preferably a urethane-urea resin (i.e., preferably has both a urethane bond and a urea bond). The urea bond can be formed when an amine compound such as a chain extender is included in the reaction raw materials. Note that, as used herein, the term "structural unit" refers to a repeating unit of a chemical structure formed during 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 ensuring that the content of urethane resin (I) is 30% by mass or more, the amount of the optional urethane resin (II) can be freely adjusted to achieve the desired effect while maintaining pigment dispersibility. On the other hand, by ensuring that the content of urethane resin (I) is 100% by mass or less, the properties of the 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, based on the total resin solids content of the urethane resin component. By ensuring that the content of urethane resin (I) is 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 the urethane resin (I) to 100% by mass or less, the properties of the urethane resin (I) can be more easily reflected in the entire liquid ink composition.

[0036] Below, we will explain the components of the reaction raw material (1) of the urethane resin (I) (the first isocyanate compound, the polycarbonate or the polyoxyalkylene compound having a structural unit of 3 to 4 carbon atoms, and the optionally blended polyester polyol, the optionally blended polyether polyol, and the optionally blended aromatic polyol), and then we will explain a preferred embodiment 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. Examples of the first isocyanate compound include those represented by the following general formula (1): (In the above general formula (1), L ５ and L ６ each independently represents a single bond or an alkylene group having 1 to 5 carbon atoms; M ２ In the above general formula (1), L represents a divalent organic group. ５ is preferably a single bond or an alkylene group having 1 to 3 carbon atoms. ６ is preferably 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 2 to 18 carbon atoms, and even more preferably 3 to 17 carbon atoms. The "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 alkyleneoxy group having 1 to 20 carbon atoms, or an arylene group having 6 to 18 carbon atoms. In addition, one or two or more non-adjacent -CH ２ - may be substituted with -O-, -COO- or -OCO-. ２ is preferably a linear, branched or cyclic alkylene group having 3 to 12 carbon atoms or an arylene group having 6 to 18 carbon atoms, not including the number of carbon atoms of the substituent. ２The substituent of is preferably an alkyl group or an alkoxy group.

[0038] Specific examples of the first isocyanate compound of the present embodiment include 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl isocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and lysine diisocyanate. Preferred examples of the first isocyanate compound include cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, dimeryl diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, methylcyclohexane diisocyanate, norbornane diisocyanate, m-tetramethylxylylene diisocyanate, 4,4-diphenylmethane diisocyanate, tolylene diisocyanate, bis-chloromethyl-diphenylmethane-diisocyanate, 2,6-diisocyanato-benzyl chloride, and dimer diisocyanate in which the carboxyl groups of dimer acid are converted to isocyanate groups. These first isocyanate compounds may be used alone or in combination of two or more. Among these, 4,4'-diphenylmethane diisocyanate, 4,4'-dibenzyl isocyanate, tolylene diisocyanate, hexamethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, methylcyclohexane diisocyanate, 4,4-diphenylmethane diisocyanate, and tolylene diisocyanate are more preferred, and tolylene diisocyanate or isophorone diisocyanate is more preferred.

[0039] In the reaction raw material (1) of the urethane resin (I) of this embodiment, the proportion of the first isocyanate compound relative to the total amount (100% by mass) of the reaction raw material (1) is preferably 5 to 60% by mass, more preferably 10 to 50% by mass, and even more preferably 15 to 40% by mass. The content of the structural unit derived from the first isocyanate compound (the so-called first isocyanate compound residue) relative to the total amount of the urethane resin (I) (resin solids) is preferably in the range of 5 to 60% by mass, more preferably 10 to 50% by mass, and even more preferably 15 to 40% by mass. When the content of the structural unit derived from the first isocyanate compound relative to 100% by mass of the urethane resin (I) is 15% by mass or more, the effect of improving the strength of polyethylene extrusion laminate is achieved. Furthermore, when the content is 40% by mass or less, the effect of improving the flexibility of the ink coating (good conformity to the substrate) is achieved.

[0040] <Polycarbonate> Examples of polycarbonates that can be used as the reaction raw material (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 is preferably a polycarbonate polyol, more preferably a polycarbonate diol. Examples of the carbonate ester include dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, ethylene carbonate, propylene carbonate, butylene carbonate, diphenyl carbonate, dinaphthyl carbonate, and phenyl naphthyl carbonate. Examples of polyols for obtaining the 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. aliphatic diols such as 1,4-cyclohexanedimethanol, 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 of this embodiment is 200 to 5,000, preferably 250 to 2,000, and more preferably 300 to 1,000. The hydroxyl value of the polycarbonate of 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 the polycarbonate is within the above range, it is easy to control the urethane bond concentration to a predetermined value or higher, thereby further improving laminate strength. The hydroxyl value in this specification is measured by the method described in the Examples section below. In this specification, the number-average and weight-average molecular weights refer to values ​​measured by gel permeation chromatography (GPC) under the following conditions: Measurement apparatus: High-speed GPC apparatus ("HLC-8220GPC" manufactured by Tosoh Corporation) Column: The following columns manufactured by Tosoh Corporation were used, connected in series: "TSKgel G5000" (7.8 mm I.D. x 30 cm) x 1, "TSKgel G4000" (7.8 mm I.D. x 30 cm) x 1, "TSKgel G3000" (7.8 mm I.D. x 30 cm) x 1, "TSKgel G2000" (7.8 mm I.D. x 30 cm) x 1 Detector: RI (differential refractometer) Column temperature: 40°C Eluent: Tetrahydrofuran (THF) Flow rate: 1.0 mL / min Injection volume: 100 μL (tetrahydrofuran solution with a sample concentration of 0.4% by mass) Standard sample: A calibration curve was prepared using the following standard polystyrene.[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 the polycarbonate relative to the total amount (100% by mass) of the reaction raw material (1) is preferably 0 to 40% by mass, more preferably 4 to 30% by mass, and even more preferably 5 to 20% by mass. The content of the polycarbonate-derived structural unit (the so-called polycarbonate residue) of this embodiment is preferably in the range of 0 to 40% by mass, more preferably 4 to 30% by mass, and even more preferably 5 to 28% by mass, relative to the total urethane resin (I) (resin solids). When the content of the polycarbonate structural unit relative to the total urethane resin (I) (resin solids) is 5% by mass or more, the effect of improving the strength of the polyethylene extrusion laminate is achieved.

[0043] <Polyoxyalkylene Compound Having Structural Units Having 3 to 4 Carbon Atoms> In this embodiment, the polyoxyalkylene compound having structural units having 3 to 4 carbon atoms refers to a compound having a polyoxyalkylene skeleton in which structural units having 3 to 4 carbon atoms are linked as repeating units, and is preferably represented by, for example, the following general formula (2). (In the above general formula (2), Q １ represents an alkylene group having 3 to 4 carbon atoms, and n2 represents the number of repeating units, which may be 1 to 200.) In the above general formula (2), (-Q ２ -O-) can be a structural 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. In addition, in the above general formula (2), n2 is preferably 1 to 100, and more preferably 2 to 30. Examples of the polyoxyalkylene compound having a structural unit having 3 to 4 carbon atoms include one or more selected from the group consisting of polytetramethylene ether glycol, polypropylene glycol, and polybutylene glycol, and polypropylene glycol is more preferred from the viewpoints of availability and cost.

[0044] The number average molecular weight (Mn) of the polyoxyalkylene compound of this embodiment is preferably 100 to 5,000, more preferably 150 to 2,000, and even more preferably 200 to 1,000. The hydroxyl value of the polyoxyalkylene compound of this embodiment can be preferably 22.44 to 1,122 mg KOH / g, more preferably 56.1 to 748 mg KOH / g, and even more preferably 112.2 to 561 mg KOH / g. When the hydroxyl value of the polyoxyalkylene compound is within the above range, it is easy to control the urethane bond concentration to a predetermined value or higher, and therefore the laminate strength can be further improved.

[0045] In the reaction raw material (1) of the urethane resin (I) of this embodiment, the proportion of the polyoxyalkylene compound having a structural unit having 3 to 4 carbon atoms is preferably 0 to 90 mass%, more preferably 2 to 90 mass%, even more preferably 3 to 50 mass%, and even more preferably 4 to 20 mass%, relative to the total amount (100 mass%) of the reaction raw material (1). The structural unit derived from the polyoxyalkylene compound having a structural unit having 3 to 4 carbon atoms of this embodiment (the so-called polyoxyalkylene residue, for example, (-Q ２ The content of the structural unit derived from the polyoxyalkylene compound is preferably in the range of 2 to 90% by mass, more preferably 4 to 20% by mass, based on the total urethane resin (I) (resin solid content). When the content of the structural unit derived from the polyoxyalkylene compound is 4 parts by mass or more based on 100 parts by mass of the urethane resin (I), the extrusion laminate strength tends to be further improved.

[0046] <Polyester Polyol> The reaction raw material (1) of the urethane resin (I) of this embodiment may contain a polyester polyol if necessary. In particular, when the urethane resin (II) described below does not contain a polyester polyol, the reaction raw material (1) of the urethane resin (I) preferably contains a 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, more preferably 40 to 80% by mass, relative to the total amount (100% by mass) of the reaction raw material (1). The content of the polyester polyol structural unit (structural unit derived from polyester polyol, so-called polyester polyol residue) of this embodiment is preferably in the range of 0 to 90% by mass, more preferably 40 to 80% by mass, relative to the total urethane resin (I) (resin solids). When the content of the polyester polyol structural unit is 30 parts by mass or more per 100 parts by mass of the 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 preferably a compound obtained by dehydration condensation or polymerization of a low-molecular-weight polyol and a polycarboxylic acid or an anhydride thereof. The polyester polyol can further improve laminate strength by introducing ester groups to increase cohesive energy.

[0048] As the low molecular weight polyol, various known compounds having two or more hydroxyl groups that are generally 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. Specific examples of the low molecular weight polyol include 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, and 1,4-cyclohexanedimethanol; 2-methyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,2-butanediol, 1,3-butanediol, and 2-butyl-2- Glycols having a branched structure 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; glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, and sorbitol can be used.

[0049] The polycarboxylic acid or anhydride thereof may be any of various known polycarboxylic acids commonly used in the production of known polyester polyols. One or more of the polycarboxylic acids or anhydrides thereof may be used in combination. Specific examples include polycarboxylic acids having 6 or less carbon atoms and two or more carboxyl groups, such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, fumaric acid, maleic acid, and the anhydrides of these acids; aromatic dicarboxylic acids, such as phthalic acid, isophthalic acid, terephthalic acid, and the 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 the anhydrides of these acids.

[0050] The polyester polyol may be any of various known polyester polyols generally used in the production of known polyurethane resins, such as polyester polyols obtained by ring-opening polymerization of cyclic ester compounds, for example, lactones such as polycaprolactone, polyvalerolactone, and poly(β-methyl-γ-valerolactone), or one or more of these 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 of 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 this range, it is easy to control the urethane bond concentration to a predetermined value or higher, and therefore the laminate strength can be further improved.

[0053] In this embodiment, it is preferable that at least one of the reactant (1) for the urethane resin (I) and the reactant (2) for the urethane resin (II) described below contains a polyester polyol (or a 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 that is more excellent in balance of blocking resistance, adhesion, lamination suitability, scratch resistance, pigment dispersibility, fluidity, and storage (aging) stability.

[0054] <Aromatic Polyol> The urethane resin (I) of this embodiment contains a specific polyol compound (a polycarbonate and / or a polyoxyalkylene compound having structural units of 3 to 4 carbon atoms, and, if necessary, a polyester polyol) as a component of the reaction raw material (1). Furthermore, an aromatic polyol compound may be further blended into the reaction raw material (1) as the polyol compound. That is, a suitable example of the urethane resin (I) of this embodiment uses polycarbonate and / or a polyoxyalkylene compound having structural units of 3 to 4 carbon atoms, a polyester polyol, an aromatic polyol compound, and a first isocyanate compound as the reaction raw materials (1). The aromatic polyol compound preferably has a partial structure represented by the following general formula (3). The urethane resin (I) having an aromatic ring more easily exhibits the effects of improving blocking properties, improving ink film gloss, and enhancing pigment dispersibility. That is, the aromatic polyol compound of this embodiment preferably has a partial structure represented by the following general formula (3). (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, provided that the alkyl group has at least one —CH ２ - may be replaced by -O-, -COO- or -OCO-, L １ and L ２ each independently represents a single bond or an alkylene group having 1 to 5 carbon atoms; ４ each independently represents a mezine group (-CH=), a trivalent alicyclic group having 3 to 15 carbon atoms, or a trivalent aromatic group; R １each independently represents a monovalent aromatic group; M １ each independently represents a mezine group (-CH=), a trivalent alicyclic group having 3 to 15 carbon atoms, or a trivalent aromatic group, and ni is the number of repeating units and represents an integer of 2 or more. In addition, * in the above general formula (3) represents a bond to another atom. In this embodiment, in the above general formula (3), D １ is preferably a hydrogen atom, a hydroxyl group, or an alkyl group having 1 to 3 carbon atoms. １ is preferably an alkylene group having 1 to 3 carbon atoms, and particularly preferably a methylene group. ２ is preferably a single bond or an alkylene group having 1 to 3 carbon atoms, more preferably a single bond. ４ is preferably a medin group. １ is preferably a monovalent aromatic group that is unsubstituted or has 1 to 4 hydrogen atoms substituted with a substituent, and is more preferably a phenyl group, naphthyl group, phenalenyl group, phenanthrenyl group, anthryl group, azulenyl group, indenyl group, indanyl group, or tetralinyl group that is unsubstituted or has 1 to 3 hydrogen atoms substituted with 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 is preferably a mezine group or a trivalent alicyclic group having 4 to 8 carbon atoms (for example, cyclohexane-triyl which may be substituted with an alkyl group having 1 to 3 carbon atoms), and is particularly preferably a mezine group. In the above general formula (3), ni is preferably an integer of 2 or more and 50 or less, and more preferably 2 or more and 10 or less.

[0055] The aromatic polyol compound of the present embodiment more preferably has a structure represented by the following general formula (3-1). (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, provided that the alkyl group has at least one —CH ２- may be replaced by -O-, -COO- or -OCO-, L １ and L ２ each independently represents a single bond or an alkylene group having 1 to 5 carbon atoms; M １ each independently represents a mezine group (-CH=), a trivalent alicyclic group having 3 to 15 carbon atoms, or a trivalent aromatic group; R ３１ each independently represents a halogen atom, an amino group, a cyano group, a hydroxyl group, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms; n31 represents an integer of 0 to 4; and ni is the number of repeating units and is an integer of 2 or more. In addition, * in the above general formula (3-1) represents a bond to another atom.

[0056] The number-average molecular weight (Mn) of the aromatic polyol compound of this embodiment is preferably 100 to 4,000, more preferably 300 to 2,000, and even more preferably 700 to 900. A number-average molecular weight (Mn) of 700 to 900 is more preferable from the viewpoint of the balance between viscosity and hardness. If the number-average molecular weight of the aromatic polyol compound is too small, the cured urethane resin film tends to be hard, resulting in reduced adhesion to the film. On the other hand, if the number-average molecular weight is too large, the cured urethane resin film tends to be brittle, resulting in reduced blocking resistance of the ink film.

[0057] The hydroxyl value of the aromatic polyol compound of 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 easy to control the urethane bond concentration to a predetermined value or higher, and therefore the laminate strength can be further improved.

[0058] In the reaction raw material (1) of the urethane resin (I) of this embodiment, the proportion of the aromatic polyol compound relative to the total amount (100% by mass) of the reaction raw material (1) is preferably 0 to 90% by mass, more preferably 0 to 40% by mass, and even more preferably 0 to 20% by mass. That is, when the urethane resin (I) further contains a structural unit derived from an aromatic polyol compound, an ink layer can be formed that has an excellent balance of blocking resistance, adhesion, lamination suitability, scratch resistance, pigment dispersibility, fluidity, and storage (aging) stability. This is particularly preferred because it can improve laminate strength. Furthermore, if necessary, the inclusion of a structural unit derived from a co-used polyol can improve the dispersibility and fluidity of the ink, and also provides the effect of improving adhesion. The content of the structural unit derived from the aromatic polyol compound (so-called aromatic polyol compound residue) of this embodiment is preferably 0 to 90% by mass, more preferably 0 to 40% by mass, relative to the total urethane resin (I) (resin solids). When the content of structural units derived from an aromatic polyol compound is 3 parts by mass or more per 100 parts by mass of urethane resin (I), the urethane resin (I) is guaranteed to have good solubility in ketone, ester, and alcohol-based solvents, resulting in good adhesion to high-performance barrier films. Furthermore, the ink film is easily resolubilized in the solvent, improving the tone reproducibility of printed matter. Furthermore, when the content is 20 parts by mass or less, the ink film has appropriate flexibility, which tends to result in good blocking resistance.

[0059] If necessary, the reaction raw material (1) may further contain a polyether polyol and / or a polyol used in combination. That is, the reaction raw material (1) essentially contains a specific polyol compound (polycarbonate and / or a polyoxyalkylene compound having a structural unit of 3 to 4 carbon atoms). The reaction raw material (1) may further contain, if necessary, one or more selected from the group consisting of polyesterpolyesterpolyol, the aromatic polyol compound, polyetherpolyol, and a polyol used in combination. In one aspect of the urethane resin (I) of this embodiment, when polyesterpolyol and polyetherpolyol are used as part of the reaction raw material (1), it is preferable that the mass ratio of the polyesterpolyol is higher than the total mass of the polyesterpolyol and polyetherpolyol. In the reaction raw material (1) of the urethane resin (I) of this embodiment, the total proportion of the polyesterpolyol and the polyetherpolyol is preferably 40 to 90 mass% and more preferably 50 to 85 mass% relative to the total amount (100 mass%) of the reaction raw material (1). That is, the polyol structure of the urethane resin (I) preferably contains a structural unit derived from a polyester polyol, which can improve laminate strength, and further preferably contains a structural unit derived from a polyether polyol, which can improve the dispersibility and flowability of the ink and also improve adhesion.

[0060] (Characteristics of Urethane Resin (I)) The urethane bond concentration of the urethane resin (I) of this embodiment is preferably 0.4 mmol / g or more, more preferably 0.8 mmol / g to 4 mmol / g, and even more preferably 1.0 mmol / g to 1.5 mmol / g. 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 1.15 mmol / g to 2.3 mmol / g. When the urethane bond concentration is 1.2 mmol / g or more, the laminate strength tends to be particularly excellent, although the mechanism is unclear. 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) of 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. A weight average molecular weight (Mw) of the urethane resin (I) of 50,000 to 100,000 is particularly preferred from the viewpoints 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 Aspect of Urethane Resin (I)) The urethane resin (I) of this embodiment is preferably a resin having a urethane bond concentration of 0.4 mmol / g or more and 4 mmol / g or less, containing urethane bonds and urea bonds, and produced from reaction raw materials (1) including a polyoxyalkylene compound having polycarbonate and / or a structural unit having 3 to 4 carbon atoms, a polyester polyol, and a first isocyanate compound. Because reaction raw materials (1) include polycarbonate and / or a polyoxyalkylene compound having a structural unit having 3 to 4 carbon atoms, which provides excellent extrusion lamination strength, and the higher the urethane bond concentration, the better the scratch resistance tends to be. Therefore, a liquid ink composition containing the urethane resin (I) is thought to be able to form an ink layer that is excellent in blocking resistance, adhesion, lamination suitability, scratch resistance, pigment dispersibility, and a balance of fluidity and storage (aging) stability. It was also confirmed that by combining the ink with the urethane resin (II) or binder resin described below, an ink layer exhibiting excellent extrusion lamination strength can be formed.

[0062] (Organic Solvent) Various organic solvents can be used as the organic solvent for use in the liquid ink composition of this embodiment, and preferably, for example, 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 solvent include toluene and xylene. Examples of the ketone-based organic solvent include acetone, methyl ethyl ketone, and methyl isobutyl ketone. Examples of the ester-based organic solvent include ethyl acetate, n-propyl acetate, butyl acetate, and propylene glycol monomethyl ether acetate. The alcohol-based organic solvent is preferably an aliphatic alcohol having a boiling point of less than 160°C, for example, an alcohol having 1 to 15 carbon atoms, and specific examples thereof include n-propanol, isopropanol, 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, and 2-pentanol. The glycol ether-based organic solvent is preferably a glycol ether solvent having a boiling point of 160°C or less, and examples thereof include at least one selected from the group consisting of ethylene glycol ethers and propylene glycol ethers. The ethylene glycol ether is preferably an ethylene glycol monoalkyl ether, and the propylene glycol ether is preferably a propylene glycol monoalkyl ether. The alkyl ether group in the ethylene glycol monoalkyl ether and propylene glycol monoalkyl ether preferably has 1 to 4 carbon atoms. Preferred ethylene glycol monoalkyl ethers are ethylene glycol monopropyl ether and ethylene glycol mono(iso)propyl ether, and preferred propylene glycol monoalkyl ethers are propylene glycol monomethyl ether.The glycol ether-based organic solvent may be esterified, and examples thereof 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 alone 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 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 may be used alone or in a mixture of two or more. In recent years, from the perspective of the working environment, it has become preferable to avoid the use of aromatic organic solvents such as toluene and xylene, and ketone-based organic solvents.

[0063] The organic solvent preferably contains the ester-based organic solvent and the alcohol-based organic solvent, and the mass ratio thereof is preferably set to 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, the ink can have excellent printability and blocking resistance. 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 in addition to the organic solvent. The water content is preferably less than 10% by mass of the total ink composition. The addition of water can control the drying properties of the ink, and in gravure printing in particular, it can beautifully reproduce the gradation areas characterized by low ink transfer. Furthermore, a water content of 1 to 5% by mass of the total liquid ink composition is particularly preferred, as this improves printability. The addition of water also makes it possible to reduce the amount of organic solvent used. Water may be added to the organic solvent in advance to form a water-containing mixed solvent, or a specific amount of water may be added separately. The liquid ink composition of this embodiment can be a one-component type that does not use a curing agent such as an isocyanate curing agent, or a two-component type that does use a curing agent, and can provide a liquid ink composition with excellent ink dispersibility and flowability.

[0065] <Water> The liquid ink composition of this embodiment may contain water as needed. When the liquid ink composition contains water, the water content is preferably 0.1 to 10% by mass based on the total mass of the liquid ink composition. By including a predetermined amount of water in the liquid ink composition, the pigment dispersibility of the urethane resin (I) and any binder resins added as needed is improved, thereby improving printability, such as highlight transfer, plate fogging, and trapping properties. 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 based on the total mass of the liquid ink composition. Furthermore, as described above, printability is further improved by using the water 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 blending 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, alcohol-based organic solvent, and glycol ether-based organic solvent is preferably 1 to 20 mass%, more preferably 2 to 15 mass%, even more preferably 3 to 10 mass%, and particularly preferably 3 to 8 mass%, based on the total mass of the liquid ink composition.

[0067] (Urethane Resin (II)) The liquid ink composition of this embodiment may contain a urethane resin (II) other than the urethane resin (I) described above. When the liquid ink composition of this embodiment contains both the urethane resin (I) and a urethane resin (II) having a chemical structure different from that of the urethane resin (I), the liquid ink composition functions to further improve the adhesion of the ink as a binder resin and can also function better as a pigment dispersing resin. The urethane resin (II) of this embodiment is not particularly limited as long as it is a urethane resin other than the urethane resin (I) described above, has a urethane bond, 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 compound. Therefore, the urethane resin (II) preferably 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, the reactive raw materials for the urethane resin (II) and the reactive raw materials for the urethane resin (I) are distinguished from each other by referring to the reactive raw materials as the reactive raw materials (2) and the reactive raw materials as the reactive raw materials (1).

[0068] When the liquid ink composition of this embodiment contains urethane resin (II), 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. When the liquid ink composition of this embodiment contains urethane resin (II), 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 solids content (100% by mass) of the urethane resin component.

[0069] <Second Isocyanate Compound> The reaction raw material (2) of the urethane resin (II) of 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. As with the first isocyanate 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. 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'-dibenzyl isocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, Examples of the second isocyanate compound include methyl cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, dimeryl diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, methylcyclohexane diisocyanate, norbornane diisocyanate, m-tetramethylxylylene diisocyanate, 4,4-diphenylmethane diisocyanate, tolylene diisocyanate, bis-chloromethyl-diphenylmethane-diisocyanate, 2,6-diisocyanato-benzyl chloride, and dimer diisocyanate in which the carboxyl group of a dimer acid is converted to an isocyanate group. These second isocyanate compounds can be used alone 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 relative to the total amount (100% by mass) of the reaction raw material (2) is preferably 5 to 50% by mass, and more preferably 15 to 40% by mass. Furthermore, the content of structural 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, and more preferably 10 to 40% by mass, relative to the urethane resin (II).

[0071] <Polyol Compound> The reaction raw material (2) for the urethane resin (II) of this embodiment contains at least a polyol compound. Examples of the polyol compound include one or more selected from the group consisting of polyester polyol (II), polyether polyol (II), and aromatic polyol compounds. <<Polyester Polyol (II)>> The reaction raw material (2) for the urethane resin (II) of this embodiment preferably contains at least a polyester polyol (II). In one aspect of the urethane resin (II) of this embodiment, when the polyester polyol (II) and the polyether polyol (II) are used as part of the reaction raw material (2), the mass proportion of the polyester polyol (II) is preferably higher than the total mass of the polyester polyol (II) and the polyether polyol (II). In the reaction raw material (2) for the urethane resin (II) of this embodiment, the combined proportion of the polyester polyol (II) and the polyether polyol (II) relative to the total amount (100% by mass) of the reaction raw material (2) is preferably 20 to 95% by mass, more preferably 50 to 90% by mass. In the reactive raw material (2) of the urethane resin (II) of this embodiment, the proportion of the polyester polyol (II) relative to the total amount (100% by mass) of the reactive raw material (2) is preferably 0 to 95% by mass, and more preferably 30 to 90% by mass. That is, the polyol structure in the urethane resin (II) preferably contains structural units derived from the polyester polyol (II), which can improve laminate strength and heat resistance. Furthermore, the polyether polyol (II)-derived structural units and / or aromatic polyol compounds preferably further contain structural units, which can improve the dispersibility and fluidity of the ink and also improve adhesion.

[0072] In this embodiment, the mass ratio of the polyester polyol (II) to the polyether polyol (II) in the polyol structure (structure having two or more hydroxyl groups) (polyester polyol (II):polyether polyol (II)) 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. When the mass ratio of the polyester polyol (II) to the polyether polyol (II) is in the range of 45:55 to 100:0, a printed matter that is less prone to blocking can be obtained, which is preferable. When the mass ratio is in the range of 55:45 to 99:1, an ink that is particularly excellent in lamination strength, adhesion, and ink dispersibility can be obtained, which is preferable. Furthermore, in the liquid ink composition of this embodiment, when a polyvinyl butyral resin is used in combination as a binder resin, compatibility is good so long as the mass ratio of the polyester polyol (II) to the polyether polyol (II) is within the range of 55:45 to 99:1, and therefore suitable storage stability and fluidity can be obtained.

[0073] The polyester polyol (II) of this embodiment is preferably a compound obtained by dehydration condensation or polymerization of a low-molecular-weight polyol and a polycarboxylic acid or an anhydride thereof. The polyester polyol (II) can further increase laminate strength by introducing an ester group to increase cohesive energy.

[0074] As the low molecular weight polyol, various known compounds having two or more hydroxyl groups that are generally 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 (II). Specific examples of the low molecular weight polyol include 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, and 1,4-cyclohexanedimethanol; 2-methyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,2-butanediol, 1,3-butanediol, and 2-butyl-2- Glycols having a branched structure 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; glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, and sorbitol can be used.

[0075] The polycarboxylic acid or anhydride thereof may be any of various known polycarboxylic acids commonly used in the production of known polyester polyols. One or more of the polycarboxylic acids or anhydrides thereof may be used in combination. Specific examples include polycarboxylic acids having 6 or less carbon atoms and two or more carboxyl groups, such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, fumaric acid, maleic acid, and the anhydrides of these acids; aromatic dicarboxylic acids, such as phthalic acid, isophthalic acid, terephthalic acid, and the 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 the anhydrides of these acids.

[0076] The polyester polyol (II) may be any of various known polyester polyols generally used in the production of known polyurethane resins, such as polyester polyols obtained by ring-opening polymerization of cyclic ester compounds, for example, lactones such as polycaprolactone, polyvalerolactone, and poly(β-methyl-γ-valerolactone), or one or more of these 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) of 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 the polyester polyol (II) is in the above range, it is easy to control the urethane bond concentration to a predetermined value or higher, and therefore the laminate strength can be further improved.

[0078] The content of the polyester polyol (II) structural unit relative to the urethane resin (II) is preferably in the range of 0 to 90% by mass, more preferably 0 to 80% by mass. When the polyester polyol (II) is 50 parts by mass or more per 100 parts by mass of the urethane resin (II), the solubility of the urethane resin (II) in ketone, ester, and alcohol-based solvents is ensured, resulting in good adhesion to high-performance barrier films. Furthermore, the resolubility of the ink film in the solvent is improved, resulting in improved tone reproducibility of printed matter. Furthermore, when the content 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 reactant (2) for the urethane resin (II) of this embodiment may contain a polyether polyol (II) other than the polyoxyalkylene compound having a structural unit of 3 to 4 carbon atoms, which is a component of the reactant (1). The polyether polyol (II), which is an optional component of the reactant (2), may be any of various polyether polyols commonly used in the production of known polyurethane resins, as long as it is other than the polyoxyalkylene compound having a structural unit of 3 to 4 carbon atoms, which is a component of the reactant (1). Furthermore, the polyether polyol (II) may be used alone or in combination of two or more. Examples include polyether polyols of polymers or copolymers of methylene oxide, ethylene oxide, propylene oxide, tetrahydrofuran, and the like. Specifically, known, general-purpose polyether polyols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol may be used. The inclusion of a polyether polyol significantly improves adhesion, particularly to high-performance barrier films, resulting in excellent blocking resistance and laminate 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 be hard, resulting in reduced adhesion to polyester films. If the number-average molecular weight is greater than 3500, the resulting resin film tends to be brittle, resulting in reduced blocking resistance of the ink film. The hydroxyl value of the polyether polyol (II) of 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. If the hydroxyl value of the polyether polyol (II) is within the above range, it is easy to control the urethane bond concentration to a predetermined value or higher, thereby further improving laminate strength.

[0081] In the reactive raw material (2) for the urethane resin (II) of this embodiment, the proportion of the polyether polyol (II) relative to the total amount (100% by mass) of the reactive raw material (2) is preferably 0 to 60% by mass, more preferably 0 to 50% by mass. The constituent units of the polyether polyol (II) are preferably contained in the range 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 the urethane resin (II), the solubility of the urethane resin (II) in ketone, ester, and alcohol-based solvents is ensured, resulting in good adhesion to high-performance barrier films. Furthermore, the resolubility of the ink film in the solvent is improved, resulting in improved tone reproducibility of printed matter. Furthermore, 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 Compound> A polyol compound is contained as an essential component of the reaction raw material (2) of the urethane resin (II) of this embodiment. The reaction raw material (2) may contain an aromatic polyol compound as the polyol compound. The aromatic polyol compound preferably has a partial structure represented by the above general formula (3), preferably general formula (3-1). The urethane resin (II) having an aromatic ring is more likely to exhibit the effects of improving blocking properties, improving the gloss of the ink coating, and enhancing pigment dispersibility.

[0083] In the reaction raw material (2) of the urethane resin (II) of this embodiment, the proportion of the aromatic polyol compound relative to the total amount (100% by mass) of the reaction raw material (2) is preferably 0 to 95% by mass, more preferably 0 to 90% by mass, and even more preferably 0 to 87% by mass. That is, the presence of structural units derived from aromatic polyol compounds in the polyol structure of the urethane resin (II) is preferred because it can improve laminate strength. Furthermore, the presence of structural units derived from a co-used polyol, if necessary, can improve ink dispersibility and fluidity, and also improve adhesion, which is preferred. In this embodiment, the content of structural units derived from aromatic polyol compounds (so-called aromatic polyol compound residues) is preferably in the range of 30 to 95% by mass, more preferably 50 to 90% by mass, based on the total urethane resin (II) (resin solids). When the content of the aromatic polyol compound-derived structural unit is 50 parts by mass or more per 100 parts by mass of the urethane resin (II), the urethane resin (II) is guaranteed to have good solubility in ketone, ester, and alcohol-based solvents, resulting in good adhesion to high-performance barrier films. Furthermore, the ink film has good resolubility in the solvent, improving the tone reproducibility of printed matter. Furthermore, when the content is 90 parts by mass or less, the ink film has appropriate flexibility, which tends to result in good blocking resistance.

[0084] (Characteristics of Urethane Resin (II)) The urethane bond concentration of the urethane resin (II) of 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 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) of 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 the urethane resin (II) of 5,000 to 150,000 is preferred from the viewpoints 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 Aspects of Urethane Resin (II)) A preferred urethane resin (II) of this embodiment can be one or two resins selected from the group consisting of resins produced from reaction raw materials (2) that include a polyol compound containing two types of polyethylene glycol, namely, the polyester polyol (II) and a polyethylene glycol not containing a carbonate group ((—O—(C═O)—O—)), and a second isocyanate compound, and resins produced from reaction raw materials (2) that include a polyol compound containing two types of aromatic polyol, namely, the polyester polyol (II) and a polyethylene glycol not containing a carbonate group ((—O—(C═O)—O—)), and a second isocyanate compound. This allows the formation of an ink layer that is more excellent in balance of blocking resistance, adhesion, lamination suitability, scratch resistance, pigment dispersibility, fluidity, and storage (aging) stability.

[0086] (Preferred Aspects of Urethane Resins (I) and (II)) Of the resin components contained 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, based on the total resin solids content of the liquid ink composition. When the contents of urethane resins (I) and (II) contained in the liquid ink composition are within the above ranges, an ink layer can be formed that is superior in blocking resistance, adhesion, boiling / laminating suitability, scratch resistance, pigment dispersibility, fluidity, and storage (aging) stability. 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-based 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, the proportion of the solid content of the entire urethane resin component relative to the total solid content of the binder resin is preferably 50% by mass or more, 57% by mass or more, 61% by mass or more, or 67% by mass or more.The upper limit of the ratio of the solid content of the urethane resin component to the total solid content of the binder resin is preferably 100% by mass or less, 95% by mass or less, or 90% by mass or less. The upper and lower limits can be combined in any manner.

[0087] The reaction raw material (1) for the urethane resin (I) and / or the reaction raw material (2) for the urethane resin (II) of this embodiment may further contain a polyol for use in combination, if necessary. As the polyol for use in combination with the urethane resin (I) and / or (II) used in the liquid ink composition of this embodiment, various known polyols that are generally used in the production of polyurethane resins can be used, and one or more types 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, pentaerythritol, etc. Examples of suitable polyols include saturated or unsaturated low-molecular-weight polyols (1); polycarbonate polyols (2) obtained by reacting the above-mentioned low-molecular-weight polyols with, for example, dimethyl carbonate, diphenyl carbonate, ethylene carbonate, phosgene, etc.; polybutadiene glycols (3); glycols (4) obtained by adding ethylene oxide or propylene oxide to bisphenol A; and acrylic polyols (4) obtained by copolymerizing, per molecule, one or more hydroxyethyl groups, hydroxypropyl acrylate, hydroxybutyl acrylate, etc., or their corresponding methacrylic acid derivatives, with, for example, acrylic acid, methacrylic acid, or an ester thereof. 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] In addition, when the above-mentioned combined polyol contains a polyester polyol (including polyester polyols (I) and (II)) and / or a polyether polyol (including polyether polyols (I) and (II)), the content of the polyester polyol and / or the polyether polyol contained in the combined polyol is also included in the mass of the polyester polyol and / or the polyether polyol in the polyol structure of the urethane resin (I) and / or the urethane resin (II), respectively.

[0089] Furthermore, in the liquid ink composition of this embodiment, at least one of the urethane bond concentrations of the urethane resin (I) and the urethane bond concentration of the urethane resin (II) is preferably 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 1.05 mmol / g or more and 2.0 mmol / g or less. When at least one of the urethane bond concentrations of the urethane resin (I) and the urethane bond concentration of the urethane resin (II) is 0.98 mmol / g or more, it becomes easier to control the urethane bond concentration of the entire urethane resin component to 0.98 mmol / g or more. Because a high urethane bond concentration tends to harden the coating film, an ink composition with particularly excellent scratch resistance can be provided.

[0090] (Method for Producing Urethane Resins (I) and (II)) The polyurethane resins (I) and (II) in the liquid ink composition of this embodiment can be produced, for example, by a two-stage method in which a polyol having two or more hydroxyl groups is reacted with an isocyanate in an excess ratio to obtain a prepolymer having terminal isocyanate groups, and the resulting prepolymer is then reacted with a chain extender and / or a terminal blocking agent in a suitable solvent; or by a one-stage method in which a polyol having two or more hydroxyl groups, an isocyanate, a chain extender, and / or a terminal blocking agent are reacted simultaneously in a suitable solvent selected from the above. Examples of the polyol having two or more hydroxyl groups include one or more selected from the group consisting of polycarbonate or a polyoxyalkylene compound having 3 to 4 carbon atoms in a structural unit, polyester polyol, polyester polyol (II), polyether polyol (II), and an aromatic polyol compound, and a combination polyol added as needed. Examples of the isocyanates include one or more compounds selected from the group consisting of a first isocyanate compound and a second isocyanate compound. Examples of the solvent include ester-based solvents commonly used as solvents for non-toluene gravure inks, such as ethyl acetate, propyl acetate, and butyl acetate; ketone-based solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; alcohol-based solvents such as methanol, ethanol, isopropyl alcohol, and n-butanol; hydrocarbon-based solvents such as methylcyclohexane and ethylcyclohexane; and mixed solvents thereof. Among the above methods, a two-stage method is preferred to obtain a uniform urethane resin (I) or (II). Furthermore, when producing urethane resin (I) or (II) by a two-stage method, it is preferable to react the chain extender and / or end-capping agent so that the total amino group (equivalent ratio) is 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, causing the urethane resin to yellow or emitting an odor after printing.Furthermore, in recent years, from the viewpoint of the working environment, it is more preferable not to use aromatic solvents such as toluene and xylene or ketone solvents.Examples of chain extenders used in the polyurethane resin of the liquid ink composition of this embodiment include ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine, and dicyclohexylmethane-4,4'-diamine. In addition, amines having a hydroxyl group in the molecule, such as 2-hydroxyethylethylenediamine, 2-hydroxyethylpropyldiamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, and di-2-hydroxypropylethylenediamine, can also be used. These chain extenders can be used alone or in combination of two or more. Furthermore, monovalent active hydrogen compounds can also be used as end-blocking agents for the purpose of terminating the reaction. Examples of such compounds include monoamines such as diethanolamine, monoethanolamine, aminomethylpropanol, cyclohexylamine, and dibutylamine, and alcohols such as ethanol and isopropyl alcohol. Furthermore, when it is particularly desired to introduce a carboxyl group into the polyurethane resin, amino acids such as glycine and L-alanine can be used as reaction terminators. These end-capping agents can be used alone 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 examples thereof include organic or inorganic pigments used in general inks, paints, recording agents, etc. In order to particularly demonstrate the excellent effect of the present disclosure of improving storage stability, the pigment is preferably an organic pigment. Examples of organic pigments include condensed polycyclic organic pigments with a cyclic structure having a benzene ring or a heterocycle, and azo pigments. Specific examples of preferred organic pigments are listed below.

[0092] The azo pigment may be any organic pigment having an azo group (-N=N-) in the molecule, and may be any of a soluble azo lake pigment, an insoluble azo pigment, and a condensed azo pigment. Examples of azo pigments include C.I. Pigment Red 10, C.I. Pigment Red 11, C.I. Pigment Red 112, C.I. Pigment Red 114, C.I. Pigment Red 119, C.I. Pigment Red 12, C.I. Pigment Red 136, C.I. Pigment Red 14, C.I. Pigment Red 144, C.I. Pigment Red 146, C.I. Pigment Red 147, C.I. Pigment Red 15, C.I. Pigment Red 150, C.I. Pigment Red 16, C.I. C.I. Pigment Red 164, C.I. Pigment Red 166, C.I. Pigment Red 17, C.I. Pigment Red 170, C.I. Pigment Red 171, C.I. Pigment Red 175, C.I. Pigment Red 176, C.I. Pigment Red 18, C.I. Pigment Red 183, C.I. Pigment Red 184, C.I. Pigment Red 185, C.I. Pigment Red 187, C.I. Pigment Red 188, C.I. Pigment Red 193, C.I. Pigment Red 2, C.I. Pigment Red 200, C.I. Pigment Red 208, C.I. Pigment Red 21, C.I. Pigment Red 210, C.I. Pigment Red 211, C.I. Pigment Red 213, C.I. Pigment Red 214, C.I. Pigment Red 22, C.I. Pigment Red 220, C.I. Pigment Red 221, C.I. Pigment Red 23, C.I. Pigment Red 237, C.I. Pigment Red 238, C.I. Pigment Red 239, C.I. Pigment Red 242, C.I. Pigment Red 243, C.I. Pigment Red 245, C.I. Pigment Red 247, C.I. Pigment Red 253, C.I. Pigment Red 256, C.I. C.I. Pigment Red 258, C.I. Pigment Red 266, C.I. Pigment Red 268, C.I. Pigment Red 269, C.I. Pigment Red 3, C.I. Pigment Red 31, C.I. Pigment Red 32, C.I. Pigment Red 38, C.I. Pigment Red 4,C.I. Pigment Red 41, C.I. Pigment Red 48, C.I. Pigment Red 48:1, C.I. Pigment Red 48:2, C.I. Pigment Red 48:3, C.I. Pigment Red 48:4, C.I. Pigment Red 49, C.I. Pigment Red 49:1, C.I. Pigment Red 49:2, C.I. Pigment Red 5, C.I. Pigment Red 50:1, C.I. Pigment Red 52:1, C.I. Pigment Red 52:2, C.I. Pigment Red 53:1, C.I. Pigment Red 54, C.I. Pigment Red 57:1, C.I. Pigment Red 58, C. C.I. Pigment Red 58:4, C.I. Pigment Red 6, C.I. Pigment Red 60, C.I. Pigment Red 60:1, C.I. Pigment Red 63, C.I. Pigment Red 63:1, C.I. Pigment Red 63:2, C.I. Pigment Red 64:1, C.I. Pigment Red 68, C.I. Pigment Red 7, C.I. Pigment Red 8, C.I. Pigment Red 9, C.I. Pigment Red 95, C.I. Pigment Yellow 1, C.I. Pigment Yellow 10, C.I. Pigment Yellow 100, C.I. Pigment Yellow 104, C.I. Pigment Yellow 105, C.I. Pigment Yellow 106, C.I. Pigment Yellow 111, C.I. Pigment Yellow 113, C.I. Pigment Yellow 114, C.I. Pigment Yellow 116, C.I. Pigment Yellow 12, C.I. Pigment Yellow 120, C.I. Pigment Yellow 124, C.I. Pigment Yellow 126, C.I. Pigment Yellow 127, C.I. Pigment Yellow 128, C.I. Pigment Yellow 13, C.I. Pigment Yellow 130, C.I. Pigment Yellow 133, C.I. Pigment Yellow 14, C.I. Pigment Yellow 15, C.I. Pigment Yellow 151, C.I. Pigment Yellow 152, C.I. C.I. Pigment Yellow 154, C.I. Pigment Yellow 155, C.I. Pigment Yellow 16, C.I. Pigment Yellow 165, C.I. Pigment Yellow 166, C.I. Pigment Yellow 167, C.I. Pigment Yellow 168, C.I. Pigment Yellow 169,C.I. Pigment Yellow 17, C.I. Pigment Yellow 170, C.I. Pigment Yellow 172, C.I. Pigment Yellow 174, C.I. Pigment Yellow 175, C.I. Pigment Yellow 176, C.I. Pigment Yellow 180, C.I. Pigment Yellow 181, C.I. Pigment Yellow 183, C.I. Pigment Yellow 191, C.I. Pigment Yellow 191:1, C.I. Pigment Yellow 194, C.I. Pigment Yellow 2, C.I. Pigment Yellow 205, C.I. Pigment Yellow 206, C.I. Pigment Yellow 209, C.I. Pigment Yellow 212, C.I. Pigment Yellow 214, C.I. Pigment Yellow 219, C.I. Pigment Yellow 3, C.I. Pigment Yellow 4, C.I. Pigment Yellow 49, C.I. Pigment Yellow 5, C.I. Pigment Yellow 55, C.I. Pigment Yellow 6, C.I. Pigment Yellow 60, C.I. Pigment Yellow 61, C.I. Pigment Yellow 62, C.I. Pigment Yellow 63, C.I. Pigment Yellow 65, C.I. Pigment Yellow 7, C.I. Pigment Yellow 73, C.I. Pigment Yellow 74, C.I. Pigment Yellow 75, C.I. Pigment Yellow 77, C.I. Pigment Yellow 81, C.I. Pigment Yellow 83, C.I. Pigment Yellow 87, C.I. Pigment Yellow 9, C.I. Pigment Yellow 93, C.I. Pigment Yellow 94, C.I. Pigment Yellow 95, C.I. Pigment Yellow 97, C.I. Pigment Yellow 98, C.I. Pigment Orange 1, C.I. Pigment Orange 13, C.I. Pigment Orange 15, C.I. Pigment Orange 16, C.I. Pigment Orange 17, C.I. Pigment Orange 17:1, C.I. Pigment Orange 19, C.I. Pigment Orange 2, C.I. Pigment Orange 22, C.I. Pigment Orange 24, C.I. Pigment Orange 3, C.I. Pigment Orange 34, C.I. Pigment Orange 36, C.I. Pigment Orange 38, C.I. Pigment Orange 4, C.I. Pigment Orange 46, C.I. Pigment Orange 5, C.I. Pigment Orange 60,Examples of pigments include C.I. Pigment Orange 62, C.I. Pigment Orange 64, C.I. Pigment Orange 72, C.I. Pigment Orange 74, C.I. Pigment Brown 25, C.I. Pigment Brown 32, C.I. Pigment Brown 5, C.I. Pigment Blue 25, C.I. Pigment Blue 26, C.I. Pigment Violet 13, C.I. Pigment Violet 17, C.I. Pigment Violet 32, and C.I. Pigment Violet 50. These pigments may be used alone or in combination.

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

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

[0095] Further, the color pigment may also be a condensed polycyclic organic pigment. The condensed polycyclic organic pigment refers to an organic pigment having a cyclic structure with a benzene ring or a heterocycle among organic pigments. Examples of the condensed polycyclic organic pigment used in the present invention include C.I. Pigment Blue 15, C.I. Pigment Blue 15:1, C.I. Pigment Blue 15:2, C.I. Pigment Blue 15:3, C.I. Pigment Blue 15:4, C.I. Pigment Blue 15:5, C.I. Pigment Blue 15:6, C.I. Pigment Blue 16, C.I. Pigment Blue 17, C.I. Pigment Blue 75, C.I. Pigment Blue 79, C.I. Pigment Green 7, C.I. Pigment Green 36, C.I. Phthalocyanine pigments such as C.I. Pigment Green 58, C.I. Pigment Green 59, C.I. Pigment Green 62, and C.I. Pigment Green 63; quinacridone pigments such as C.I. Pigment Violet 19, C.I. Pigment Violet 42, C.I. Pigment Violet 55, C.I. Pigment Red 122, C.I. Pigment Red 202, C.I. Pigment Red 206, C.I. Pigment Red 207, C.I. Pigment Red 209, C.I. Pigment Orange 48, and C.I. Pigment Orange 49; C.I. Pigment Violet 23, C.I. Pigment Violet 34, C.I. Pigment Violet 35, and C.I. Dioxazine pigments such as C.I. Pigment Violet 37 and C.I. Pigment Blue 80, perylene pigments such as C.I. Pigment Red 123, C.I. Pigment Red 149, C.I. Pigment Red 178, C.I. Pigment Red 179, C.I. Pigment Red 190, C.I. Pigment Red 224, C.I. Pigment Violet 29, C.I. Pigment Black 31 and C.I. Pigment Black 32, perylene pigments such as C.I. Pigment Orange 43 and C.I. Pigment Red 194, perinone pigments such as C.I. Pigment Yellow 109, C.I. Pigment Yellow 110, C.I. Pigment Yellow 173, C.I. isoindolinone pigments such as C.I. Pigment Yellow 179, C.I. Pigment Orange 61, C.I. Pigment Brown 38, C.I. Pigment Yellow 139,Isoindoline pigments such as C.I. Pigment Yellow 185, C.I. Pigment Orange 66, C.I. Pigment Orange 69, and C.I. Pigment Red 260, thioindigo pigments such as C.I. Pigment Red 88, C.I. Pigment Red 181, C.I. Pigment Red 279, C.I. Pigment Violet 36, and C.I. Pigment Violet 38, C.I. Pigment Red 83, C.I. Pigment Red 89, C.I. Pigment Red 168, C.I. Pigment Red 177, C.I. Pigment Red 182, C.I. Pigment Red 216, C.I. Pigment Red 226, and C.I. Anthraquinone pigments such as C.I. Pigment Red 251, C.I. Pigment Red 263, C.I. Pigment Blue 60, C.I. Pigment Yellow 24, C.I. Pigment Yellow 99, C.I. Pigment Yellow 108, C.I. Pigment Yellow 123, C.I. Pigment Yellow 199, C.I. Pigment Violet 31, C.I. Pigment Orange 40, C.I. Pigment Orange 51, C.I. Pigment Violet 5:1, C.I. Pigment Black 20, etc.; quinophthalone pigments such as C.I. Pigment Yellow 138 and C.I. Pigment Yellow 231, C.I. Pigment Orange 71, C.I. Pigment Orange 73, C.I. Examples of the pigment include diketopyrrolopyrrole pigments such as C.I. Pigment Orange 81, C.I. Pigment Red 254, C.I. Pigment Red 255, C.I. Pigment Red 264, C.I. Pigment Red 270, and C.I. Pigment Red 272, and metal complex pigments such as C.I. Pigment Yellow 117, C.I. Pigment Yellow 129, C.I. Pigment Yellow 150, C.I. Pigment Yellow 153, C.I. Pigment Orange 65, C.I. Pigment Orange 68, C.I. Pigment Red 257, C.I. Pigment Red 271, C.I. Pigment Green 8, and C.I. Pigment Green 10.

[0096] The fused polycyclic organic pigment used in this embodiment may be a commercially available product, or may be manufactured by a known, commonly used method. Of course, after manufacturing, the pigment may be subjected to appropriate known treatments, such as pigment derivative treatment, surfactant treatment, rosin treatment, or resin treatment. Furthermore, the pigment particle size, particle shape, and particle surface charge may be adjusted and controlled for printing inks, paints, colored molded products, stationery, textile printing, toner, color filters, inkjet inks, and cosmetics. When a fused polycyclic organic pigment with a high specific surface area as measured 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 fused polycyclic organic pigment as measured by the BET method should be 20 to 130 m. ２ / g, and 50 to 100m ２ / g is more preferred.

[0097] Examples of inorganic pigments include white inorganic pigments such as titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, lithopone, antimony white, and gypsum. Among inorganic pigments, titanium oxide is particularly preferred. Titanium oxide exhibits a white color and is preferred in terms of coloring power, hiding power, chemical resistance, and weather resistance. From the viewpoint of printing performance, titanium oxide 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, yellow lead, cadmium yellow, cadmium red, ultramarine, Prussian blue, red iron oxide, yellow iron oxide, iron black, and zircon. Aluminum is in powder or paste form, but it is preferably used in paste form from the standpoints of handleability and safety, and whether leafing or non-leafing aluminum is used is selected appropriately from the standpoints of brightness and concentration.

[0099] As the carbon black, commercially available carbon black can be used. There are no particular limitations on the carbon black that can be used, and various commercially available carbon blacks such as oil furnace black, gas furnace black, channel black, and acetylene black produced by the contact method, furnace method, thermal method, etc. may be used. The particle diameter of the carbon black is, for example, 5 to 200 nm, preferably 20 to 50 nm. The nitrogen adsorption specific surface area of ​​the carbon black is, for example, 20 to 500 m ２ / g, preferably 30 to 150 m ２ The DBP oil absorption of carbon black is, for example, 20 to 150 cm ３ / 100g, preferably 30 to 120cm ３ The volatile content of the carbon black is, for example, 0.1 to 10.0%. The pH value of the carbon black is, for example, 1 to 10, preferably 2 to 9.

[0100] Examples of commercially available carbon black 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, and #260 (all manufactured by Mitsubishi Chemical Corporation), and 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 Corporation), "Raven 7000, 3500, 5250, 5750, 5000ULTRA II, 1255, 1250, 1190, 1000, 1020, 1035, 1100ULTRA, 1170, 1200" (all manufactured by Columbian Chemicals), "SUNBLACK 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 Pigment> The pigment used in the liquid ink composition of this embodiment is an organic pigment or inorganic pigment used in general inks, paints, and recording materials as described above, and has a base adsorption amount per surface area of ​​the pigment of 0.30 μmol / m ２ It is preferable to use a pigment having a base adsorption amount per surface area of ​​the pigment of 0.30 μmol / m or more. ２ The use of the above pigments can improve the dispersion stability of inks using these pigments. Therefore, the problem of reduced pigment dispersibility that occurs in ink systems that do not contain vinyl chloride vinyl acetate copolymer can be alleviated, and therefore it is preferable to use these pigments in combination with ink systems that do not contain vinyl chloride vinyl acetate copolymer. The reason for this is unclear, but one possible reason is that when the base adsorption amount per surface area of ​​the colorant is large, the basic substance in the liquid ink composition or the polar moiety of the binder resin is adsorbed to the pigment surface, resulting in excellent dispersibility of the pigment itself. For example, when polyvinyl butyral is not used in the liquid ink composition of this embodiment, the base adsorption amount per surface area of ​​the pigment is 0.30 μmol / m ２ In order to obtain the above-mentioned effects, it is more preferable to use a pigment having a base adsorption amount per surface area of ​​the pigment of 0.30 μmol / m ２ or more, and ２ It is preferable that the thickness is 0.40 μm / m or more. ２ More preferably, it is 0.50 μm / m or more. ２ On the other hand, there is no particular upper limit to the amount of base adsorption, but it is preferably 2.00 μmol / m ２ It is preferable that:

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

[0103] <Preferred embodiment of pigment> The pigment used in the liquid ink composition of this embodiment has a base adsorption amount per surface area of ​​the pigment of 0.3 μmol / m as measured by the above-mentioned method. ２ In the above cases, commercially available products or those obtained by ordinary manufacturing methods can be used as they are. In addition, the amount of base adsorption per surface area of ​​the pigment is 0.3 μmol / m ２ The pigment may be subjected to a treatment (hereinafter referred to as "base adsorption treatment") that achieves the above-described results. One example of the base adsorption treatment is a method of treating the surface of the pigment with an iron salt or the like. The method of treating with an iron salt preferably includes a pigment slurry production step of adding a 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 pigment surface treatment step of filtering the reaction solution, drying the residue, and pulverizing it. The solvent used in the base adsorption treatment can be water and / or an organic solvent, and examples of the organic solvent include methanol, ethanol, n-propanol, and i-propanol. Water is particularly preferred from the standpoint of economy. The water may 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] The amount of the pigment used as a raw material added relative to 100 parts by mass of the solvent used in the base adsorption treatment is preferably 1 to 30 parts by mass. If the amount added is small, productivity will be low, and if the amount added is large, the pigment slurry will become highly viscous and excessive energy will be required for stirring. Therefore, the amount is more preferably 2 to 20 parts by mass, and particularly preferably 3 to 12 parts by mass.

[0105] Examples of iron compounds that can be used include iron sulfate, iron chloride, iron fluoride, iron bromide, iron iodide, iron nitrate, iron phosphate, iron borate, iron carbonate, and iron acetate. From the viewpoint of economy, iron sulfate, iron chloride, and iron nitrate are preferred. Divalent or trivalent iron can be used as the iron. The iron compound may be anhydrous or hydrated.

[0106] The temperature in the pigment slurry production step is preferably 0°C to 100°C. The temperature in the pigment surface treatment step is preferably 0°C to 100°C. At low temperatures, the reaction rate of the pigment surface treatment reaction is slow, while at high temperatures, decomposition of hydrogen peroxide is promoted. Therefore, 10°C to 90°C is more preferable, and 20°C to 80°C is particularly preferable. The reaction time in the pigment surface treatment step is preferably 10 minutes to 2 hours. The pH of the treatment solution in the pigment surface treatment step is preferably 1 to 7, because iron ions precipitate when the solution is alkaline.

[0107] Examples of the oxidizing agent that can be used include hydrogen peroxide, permanganate, hypochlorous acid, chlorous acid, chloric acid, perchloric acid, peroxodisulfate, chromic acid, dichromate, and ozone. Among these, hydrogen peroxide diluted with water to a concentration of 20 to 50% by mass is preferred. The amount of oxidizing agent used may vary depending on the concentration, provided it is an amount suitable for the oxidation reaction, but is typically 10 to 100 parts by mass, and preferably 20 to 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, and more preferably 2 to 15% by mass, based on the raw pigment.

[0108] The iron compound and the oxidizing agent may be added to the pigment slurry simultaneously or separately. When added simultaneously, the iron compound and the oxidizing agent may be mixed together before addition. When added separately, the iron compound may be added first, or the oxidizing agent may be added first. Furthermore, the oxidizing agent may be added dropwise or all at once.

[0109] The pigment obtained by the above treatment has polar groups formed on the surface of the pigment, and the amount of base adsorption per surface area of ​​the pigment is 0.3 μmol / m ２ It is presumed that the treated pigment particle surfaces have increased hydrophilicity compared to untreated pigments, which increases wettability with solvents, resulting in 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 the pigment, 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 for the amount of iron element contained in the pigment, but it preferably 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 preferably contains 200 ppm or more of iron element per 100 parts by mass of the azo pigment, preferably 500 ppm or more, more preferably 1000 ppm or more, and even more preferably 3,000 ppm or more. On the other hand, the azo pigment preferably 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. When carbon black is used, the azo pigment preferably contains 200 ppm or more of iron element per 100 parts by mass of carbon black, preferably 500 ppm or more, more preferably 1,000 ppm or more, and even more preferably 3,000 ppm or more. On the other hand, the azo pigment preferably contains 20,000 ppm or less of iron element per 100 parts by mass of carbon black, more preferably 18,000 ppm or less, and even more preferably 15,000 ppm or less.

[0111] The iron element is not limited to simple iron (Fe), but also includes iron oxide (FeO, Fe ２ O ３ etc.) and iron hydroxide (Fe(OH) ２ , Fe(OH) ３ The iron content of the pigment may be measured as the amount of iron element, even if the iron compound is an iron compound such as iron stearate or iron stearate. The amount of iron element contained in the pigment can be measured using an energy dispersive X-ray fluorescence analyzer, PANalytical Epsilon 5 (manufactured by Spectris Co., Ltd.).

[0112] In the liquid ink composition of this embodiment, the pigment content is preferably an amount sufficient to ensure the concentration and coloring power of the liquid ink composition, that is, the pigment content is preferably 1 to 70 mass % and more preferably 5 to 60 mass % relative to the total amount of the liquid ink composition (100 mass %). The solids mass ratio in the liquid ink composition is preferably 10 to 80 mass % relative to the total amount of all solids in the ink composition. The pigments can be used alone or in combination of two or more types. When two or more types are used in combination, the base adsorption amount per surface area of ​​at least one pigment is 0.30 μmol / m ２ Furthermore, when the liquid ink composition of this embodiment contains polyvinyl butyral, from the viewpoint of the dispersibility of the polyvinyl butyral and the combination with the urethane resin component of this embodiment, the base adsorption amount per surface area is 0.30 μmol / m ２ Less than 1000 ppm of pigment can be used.

[0113] (Other Resins) In addition to the urethane resin (I) and, if necessary, the urethane resin component or urethane resin (II), the liquid ink composition of this embodiment may contain other resins that can be used in combination in the ink technical field. The other resins may be binder resins or dispersing resins, but are preferably added as binder resins. 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, and polyurethane resins other than the urethane resins (I) and (II). Among these, 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 aspect of this embodiment, the ink composition preferably contains at least one resin selected from polyvinyl butyral resins, maleic acid resins, cellulose resins, polyester resins, acrylic resins, and polyamide resins. Furthermore, from the viewpoint of reducing environmental impact, the ink composition of the present disclosure preferably does not contain chlorine-based resins. These resins can be used alone or in combination of two or more. The content of the co-resin is preferably 0.1 to 25% by mass, more preferably 2 to 15% by mass, based on the total mass of the ink.

[0114] <Rosin-Modified Maleic Acid Resin> The rosin-modified maleic acid resin is an alkyd resin obtained by reacting a polyhydric alcohol such as glycerin, pentaerythritol, or ethylene glycol with an adduct of rosin and maleic acid obtained by Diels-Alder reaction. The acid value is determined by the blending ratio of the polyhydric alcohol reacted with the adduct of rosin and maleic acid and the degree of esterification. In addition to the polyhydric alcohol, a polybasic acid may also be used in combination to form a structure in which a long-chain alkyd resin is bonded to the rosin skeleton.

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

[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 alkyd resin, and a styrene-based monomer may be reacted with this to produce a rosin-modified styrene-maleic acid resin, which is also included in the rosin-modified maleic acid resin.

[0117] <Polyvinyl butyral-based resin> The liquid ink composition of this embodiment preferably further contains a polyvinyl butyral-based resin as a binder resin. This polyvinyl butyral-based resin has the binding and dispersing properties of a binder resin, and because its constituent elements are only carbon, hydrogen, and oxygen atoms, it is more environmentally friendly than vinyl chloride-vinyl acetate copolymer resins. Furthermore, when the liquid ink composition contains a pigment, dispersing the pigment by grinding with a polyvinyl butyral-based resin causes the appropriate group—butyral group, polyvinyl alcohol residue, or vinyl acetate residue—to adsorb to the pigment, resulting in steric hindrance from the bulky butyral group. Therefore, using a combination of urethane resin (I) and a polyvinyl butyral-based resin provides better dispersion stability than dispersing the pigment with urethane resin (I) alone. As the polyvinyl butyral-based resin of this embodiment, any known resin can be used without any particular limitation. Generally, the polyvinyl butyral-based resin can be a reaction product obtained by acetalizing polyvinyl alcohol with an aldehyde compound such as butyraldehyde by a known reaction. The polyvinyl butyral-based resin of the present embodiment is represented by the following general formula (4): (In the above general formula (4), n4 and n5 each independently represent an integer of 1 or more, and R６ represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms. ６ preferably represents 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. Examples of the hydrocarbon group include an alkyl group, an alkenyl group, an aryl group, or an aralkyl group, and may be linear, branched, or cyclic. Of these, an alkyl group is preferred. Of these, R ６ As described above, the polyvinyl butyral resin of the present embodiment is a resin obtained by reacting polyvinyl alcohol and an aldehyde compound as raw materials. ６ When represented as —C(═O)H, R in the general formula (4) ６ is a hydrocarbon group derived from an aldehyde compound used in synthesizing polyvinyl butyral resins.

[0118] A suitable polyvinyl butyral-based resin in this 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). (In the above general formula (5), n6 is independently an integer of 1 or more, and R ７ represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. (In the general formula (6), each n7 is independently an integer of 1 or more.)

[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. ７More preferred examples of the alkyl group include 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, and a tert-butyl group. Furthermore, when the polyvinyl butyral-based resin of this embodiment is represented by a resin having a partial structure represented by general formula (4) above, a partial structure represented by general formula (5) below, and a partial structure represented by general formula (6) below, the content of the partial structure represented by general formula (5) relative to the total amount of the polyvinyl butyral-based 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 adjusting the content of the partial structure represented by general formula (5) above in the polyvinyl butyral-based resin to fall within the above range, an ink layer having an excellent balance between fluidity and dispersibility can be obtained.

[0120] The weight-average molecular weight of the polyvinyl butyral resin of 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 curing properties can be achieved, and the coating film can have both strength and appropriate flexibility. Furthermore, polyvinyl butyral resins with a weight-average molecular weight of 5,000 to 150,000 are easily available, and the use of such polyvinyl butyral resins makes it possible to obtain an ink layer with an excellent balance of fluidity and dispersibility.

[0121] The glass transition temperature (hereinafter, sometimes referred to as Tg) of the polyvinyl butyral resin of 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 to 110° C. In the present 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% by mass, and more preferably 15 to 30% by mass. By adjusting the hydroxyl group content of the polyvinyl butyral resin to fall within the above range, an ink layer with an excellent balance of fluidity and dispersibility can be obtained. The hydroxyl group content refers to the content of the partial structure represented by the general formula (6) relative to the total amount of the polyvinyl butyral resin.

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

[0124] The content (solid content) of the polyvinyl butyral 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, based on the total resin solid content (100% by mass) of the ink composition. Adding a total of 0.1% by mass or more of the polyvinyl butyral resin tends to maintain the adhesion and transferability of the ink film, while keeping the total content 5% by mass or less can maintain the lamination strength of the ink. The lower limit of the solid content mass ratio of the 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. The upper limit of the solid content mass ratio of the 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-Based Resins> Examples of the cellulose-based resins include cellulose ester resins such as cellulose acetate propionate, cellulose acetate butyrate, and other cellulose ester resins; nitrocellulose (also known as soluble cellulose); hydroxyalkyl cellulose; and carboxyalkyl cellulose. The cellulose ester resin preferably has an alkyl group, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, or a hexyl group. The alkyl group may further have a substituent. Of the above, cellulose acetate propionate, cellulose acetate butyrate, and nitrocellulose are preferred, with cellulose acetate propionate and cellulose acetate butyrate being particularly preferred. The molecular weight is preferably a weight-average molecular weight of 5,000 to 200,000, more preferably 10,000 to 50,000. Furthermore, a glass transition temperature of 120°C to 180°C is more preferred. When used in combination with the polyurethane resin of the present invention, it is expected that the ink film properties such as blocking resistance and scratch resistance will be improved. Nitrocellulose (nitrocellulose) is preferably obtained by reacting natural cellulose with nitric acid to form a nitric acid ester in which three hydroxyl groups in the six-membered ring of the anhydroglucopyranose group in the natural cellulose are substituted with nitric acid groups.

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

[0127] <Chlorine-Based Resin> In the liquid ink composition of this embodiment, the content of a chlorine-based resin (or chlorine-containing resin), for example, a vinyl chloride-vinyl acetate copolymer resin (solid content) is preferably less than 4.5 mass%, more preferably less than 2.5 mass%, even more preferably less than 1.2 mass%, and even more preferably less than 0.5 mass%, based on the total solid content of the liquid ink composition. Similarly, the content of a hydroxyl-containing vinyl chloride-vinyl acetate copolymer resin (solid content) is preferably less than 4.5 mass%, more preferably less than 2.5 mass%, even more preferably less than 1.2 mass%, and even more preferably less than 0.5 mass%, based on the total solid content of the liquid ink composition. This makes it possible to provide an environmentally friendly ink that is free of chlorine-based resins. In inks currently used for lamination, a combination of a polyurethane resin and a chlorine-based resin, such as a vinyl chloride-vinyl acetate copolymer resin, is widely used as a binder resin combination that can achieve both excellent dispersibility and high film properties. In particular, the combination of a chlorine-based resin and a polyurethane resin is highly effective in achieving good printability and the various physical properties required for a laminating ink (adhesion to substrates, lamination strength, and boiling retort suitability). However, when emphasizing the provision of environmentally friendly inks, it becomes necessary to eliminate chlorine-based resins such as vinyl chloride-vinyl acetate copolymer resins. However, if the amount of chlorine-based resins such as vinyl chloride-vinyl acetate copolymer resins used is less than the specified amount or is not used at all, a decrease in extrusion laminate strength becomes an issue. However, in the present disclosure, it has been confirmed that by combining a specific urethane resin (I) with the urethane bond concentration of the urethane resin component containing the urethane resin (I) or with other binder resins, it is possible to impart sufficient extrusion laminate strength to the ink even with a binder resin composition free of chlorine-based resins such as vinyl chloride-vinyl acetate copolymer. In this embodiment, the liquid ink composition contains at least a binder resin containing a urethane resin component and an organic solvent, and 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 an environmentally friendly ink that is free of chlorine-based resins. The vinyl chloride-vinyl acetate copolymer resin 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. Furthermore, the vinyl chloride-vinyl acetate copolymer resin may contain units of a monomer (other monomer) other than the vinyl chloride monomer units and vinyl acetate monomer units, as needed. The other monomer is not particularly limited as long as it is copolymerizable with vinyl chloride and vinyl acetate.

[0128] (Additives) The liquid ink composition of this embodiment preferably further contains, as necessary, one or more additives selected from the group consisting of silica, amide wax, dispersants, antifoaming agents, extender pigments, pigment dispersants, leveling agents, antifoaming agents, waxes, dispersants, plasticizers, infrared absorbers, ultraviolet absorbers, aromatics, and flame retardants. In the liquid ink composition of this embodiment, the content of the additives (solid content) relative to the total amount of the ink composition is preferably 0.1 to 20.0 mass%.

[0129] The liquid ink composition of this embodiment may further contain a dispersant, if necessary. To stably disperse the pigment in an organic solvent, a resin alone is sufficient. However, a dispersant can also be used in combination to further stabilize the pigment dispersion. Examples of dispersants include anionic, nonionic, cationic, and amphoteric surfactants. Examples include comb-structured polymers in which polyethyleneimine is polyester-added, or alkylamine derivatives of α-olefin maleic acid polymers. Specific examples include the Solsperse series (ZENECA), the Ajisper series (Ajinomoto), and the Homogenol series (Kao). The BYK series (BYK-Chemie) and the EFKA series (EFKA) can also be used as appropriate. From the perspective of ink storage stability, the dispersant content in the ink is preferably 0.05% by mass or more of the total mass of the ink composition, and from the perspective of lamination suitability, it is preferably 5% by mass or less, more preferably 0.1 to 2% by mass.

[0130] (Method of producing liquid ink composition) The liquid ink composition of this embodiment can be produced by dissolving and / or dispersing a resin, a pigment, etc. in an organic solvent. Specifically, a pigment dispersion is produced by dispersing a pigment in an organic solvent using a polyvinyl butyral resin, and the ink can be produced by blending other compounds, resins, etc. with the resulting pigment dispersion. The pigment may be dispersed using a urethane resin component, other resins, or a dispersant, but it is preferable to disperse the pigment using a polyvinyl butyral resin, etc.

[0131] The particle size distribution of the pigment in the pigment dispersion can be adjusted by appropriately adjusting the size of the grinding media of the disperser, the packing ratio of the grinding media, the dispersion treatment time, the discharge speed of the pigment dispersion, the viscosity of the pigment dispersion, etc. As the disperser, commonly used devices such as a roller mill, ball mill, pebble mill, attritor, sand mill, etc. can be used. If air bubbles or unexpectedly large particles are present in the ink, they are preferably removed by filtration or the like, as they will degrade the quality of the printed material. 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 sedimentation of the pigment and adequately dispersing it, and 1000 mPa·s or less from the viewpoint of workability during ink production and printing. The above viscosity is measured at 25°C using a Tokimec B-type viscometer. The viscosity of the ink composition can be adjusted by appropriately selecting the types and amounts of raw materials used, such as urethane resin (I), urethane resin (II), binder resins other than urethane resins (I) and (II) (e.g., polyvinyl butyral-based resins), pigments, organic solvents, etc. The viscosity of the ink can also be adjusted by adjusting the particle size and particle size distribution of the pigment in the ink.

[0133] The hues of the liquid ink composition of this embodiment include five process basic colors (yellow, crimson, indigo, black, and white) depending on the type of pigment used, and three process gamut colors (red (orange), grass green, and purple). Furthermore, transparent yellow, peony, vermilion, brown, gold, silver, pearl, and a nearly transparent medium (containing an extender pigment as needed) for adjusting color density are prepared as base colors. For boil retort inks, the pigments are appropriately selected taking into consideration their migration properties and heat resistance.

[0134] (Printed Matter) The liquid ink composition of this embodiment can be printed to produce a printed matter. Printing methods using known printing plates, such as gravure printing and flexographic printing, are possible, with gravure printing being particularly preferred. Known cylinders, such as engraved and etching types, are used for gravure printing. The layer on which a desired design is formed using the liquid ink composition of this embodiment is referred to as a printed layer. This printed layer may be a single layer, or there may be multiple printed layers. When there are multiple printed layers, the ink compositions used for each printed layer may be the same, or may be the same composition with only the pigments differing, or may be different compositions. When there are multiple printed layers, for example, a printed matter may have a first printed layer formed from a colored ink composition, a second white printed layer formed from a white ink, and a third white printed layer, in this order. The first printed layer can form a pattern using a pigment, and the second white printed layer formed with white liquid ink and the third printed layer can be used as a background for the pattern. If the second or third printed layer is an overprint varnish, it does not need to contain a colorant such as a pigment.

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

[0136] (Laminated Laminate) The present disclosure may be a laminated laminate having a substrate and a printed layer formed by printing a liquid ink composition on at least a portion of the substrate surface. The printed layer on the substrate surface may be in direct or indirect contact with the surface of the substrate. Preferred configurations of the laminated laminate of this embodiment include, for example, the following (1) to (4): (1) substrate / adhesive layer / printed layer / substrate (2) substrate / adhesive layer / substrate / printed layer / adhesive layer / substrate (3) substrate / adhesive layer / first printed layer / second printed layer / substrate (4) substrate / adhesive layer / barrier layer / printed layer / adhesive layer / substrate (5) substrate / printed layer / adhesive layer / substrate However, the laminated laminate of this embodiment is not limited to the above (1) to (4) and may further include an additional substrate. When multiple substrates are included, the substrates may be the same or different. The substrate may be a sealable sealant film or a multilayer film including a sealant layer formed by a heat sealing agent or the like, and the sealable layer is referred to as a sealant layer. The adhesive layers may have the same composition or different compositions. Furthermore, 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 printing on a wide variety of substrates, from general-purpose films to various high-performance films. Usable plastic films are not particularly limited, and examples include 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 such as 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, and mixtures thereof; various high-performance films coated with inorganic or organic barrier coating materials on their surfaces; and laminates thereof. Among these, films made of polyester, polyamide, polyethylene, and polypropylene are particularly preferred. These films may be unstretched or stretched, and their manufacturing methods are not limited. The base film may be a multilayer film produced by co-extrusion of the resins of each layer, or a multilayer sealant film having a sealant layer as the outermost layer of the multilayer film. The thickness of the base film is not particularly limited, but is usually in the range of 1 to 500 μm.

[0138] The substrate may be formed from a biomass polyolefin. The biomass polyolefin refers to a polyolefin resin using a plant-derived olefin as a raw material monomer. The raw material monomer may contain a petroleum-derived monomer, and may not contain 100% plant-derived monomers. Commercially available biomass polyolefins may also be used. Examples of commercially available products include SGM9450F, SLL118, SLL118 / 21, SLL218, SLL318, SLH118, SLH218, and SLH0820 manufactured by Braskem.

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

[0140] The vapor-deposited layer may be, 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), yttrium (Y), etc. Vapor-deposited films of inorganic oxides such as silicon oxide and aluminum oxide are transparent.

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

[0142] The vapor deposition layer can be formed on the surface of the substrate or the like by a physical vapor deposition method (PVD method) such as vacuum deposition, sputtering, or ion plating, or a chemical vapor deposition method (CVD method) such as plasma chemical vapor deposition, thermal chemical vapor deposition, or photochemical vapor deposition.

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

[0144] Examples of the metal-deposited film include a VM-CPP film obtained by depositing a metal such as aluminum on a CPP film, and a VM-OPP film obtained by depositing a metal such as aluminum on an OPP film. Examples of the transparent deposited film include films obtained by depositing silica or alumina on an OPP film, PET film, nylon film, or the like. For the purpose of protecting the inorganic deposited layer of silica or alumina, a film with a coating applied to the deposited layer may also be used.

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

[0146] <Lamination Method> The lamination method for producing the laminate of the present embodiment is not particularly limited, and examples thereof include dry lamination, wet lamination, non-solvent lamination, extrusion lamination, etc. In this case, the layer located between the substrates is referred to as an adhesive layer.

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

[0148] In the two-component curing adhesive, in consideration of the creation of a sustainable recycling-based society (sustainability), it is preferable to use plant-derived materials (biomass materials) as raw materials for the polyisocyanate composition or polyol composition. By appropriately using biomass materials, the environmental impact can be reduced. Examples of biomass materials include castor oil-based polyols such as castor oil, dehydrated castor oil, hydrogenated castor oil (a hydrogenated castor oil), and 5 to 50 mol alkylene oxide adducts of castor oil; aliphatic polybasic acids such as succinic acid, succinic anhydride, glutaric acid, adipic acid, azelaic acid, sebacic acid, and itaconic acid; alkyl esters of these acids; and dimer acids.

[0149] Commercially available adhesives using biomass raw materials can also be used, such as those listed by the Japan Organics Resources Association, including DIC Dry BM (manufactured by DIC Corporation) and Takenate BM (manufactured by Mitsui Chemicals, Inc.).

[0150] The weight of the adhesive layer after drying is 0.1 to 10 g / m ２ It is preferable that the density is 1 to 6 g / m ２ More preferably, it is 2 to 5 g / m ２ 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] Although various types of adhesives can be used for the adhesive layer, it is preferable to use a pressure-sensitive adhesive. Examples of such pressure-sensitive adhesives 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 rubber-based adhesives blended with tackifiers such as abiethylene acid rosin ester, terpene-phenol copolymer, and terpene-indene copolymer, and acrylic-based adhesives obtained by dissolving an acrylic copolymer having a glass transition temperature of 20°C or less, such as 2-ethylhexyl acrylate-n-butyl acrylate copolymer or 2-ethylhexyl acrylate-ethyl acrylate-methyl methacrylate copolymer, in an organic solvent.

[0152] When a material having gas barrier properties is used as the adhesive or the anchor coating agent described below, a laminate film having particularly excellent gas barrier properties can be obtained. ２ The oxygen barrier property of the cured coating film of the adhesive applied at (solid content) is 300 cc / m ２ / day / atm or less, or water vapor barrier property of 120 g / m ２ Commercially available products include the "PASLIM" series, such as PASLIM VM001 and PASLIM J350X manufactured by DIC Corporation, and "MAXIEVE" manufactured by Mitsubishi Gas Chemical Company, Inc.

[0153] The adhesive layer can also be formed from a thermoplastic resin, and can be formed by a conventionally known method, such as melt extrusion lamination or sand lamination. The liquid ink composition of the present invention is preferably laminated by extrusion lamination or sand lamination, particularly to improve the interlayer adhesion strength of the extrusion laminate. Examples of thermoplastic resins that can be used for 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 and hydrogenated products thereof, such as ring-opening polymers (COP) of norbornene monomers and norbornene copolymers (COC) obtained by copolymerizing norbornene monomers with olefins such as ethylene; vinyl alicyclic hydrocarbon polymers; and cyclic polyolefin resins such as cyclic conjugated diene polymers. Examples of suitable elastomers include polyethylene-based elastomers such as ethylene-vinyl acetate copolymer (EVA) and ethylene-α-olefin copolymers, polypropylene-based elastomers, and butene-based elastomers; ethylene-based 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 ionomers of ethylene-acrylic acid copolymers and ionomers of ethylene-methacrylic acid copolymers. Furthermore, in order to improve interlayer adhesion, acid-modified polyolefin-based resins obtained by modifying the above-mentioned polyolefin-based resins with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid can also be used. In addition, resins obtained by graft polymerizing or copolymerizing a polyolefin resin with an unsaturated carboxylic acid, an unsaturated carboxylic anhydride, or an ester monomer can also be used. These resins can be used alone or in combination of two or more.It is also preferable to use the polyethylene resin using the above-mentioned biomass-derived ethylene as a monomer unit.

[0154] When laminating an adhesive layer using extrusion lamination, an anchor coating layer may be formed by applying and drying an anchor coating agent to the surface of the layer to be laminated. Examples of anchor coating agents include anchor coating agents made of any resin with a heat resistance temperature of 135°C or higher, such as polybutadiene-based resins, urethane resins, polyisocyanate-polyether polyols, polyethyleneimine, vinyl-modified resins, epoxy resins, polyester resins, and alkyl titanates, as well as anchor coating agents obtained by diluting the above adhesives with organic solvents. Among these, polyethyleneimine-based anchor coating agents and anchor coating agents obtained by diluting the above adhesives with organic solvents are preferred. A silane coupling agent may also be used as an additive, and soluble nitrocellulose may also be used to enhance heat resistance.

[0155] (Packaging Material) The packaging material of this embodiment preferably comprises a laminated laminate containing a printed layer formed from the liquid ink composition, and more preferably comprises a laminated laminate containing the ink composition. For example, the packaging material may be formed by arranging two laminated laminates so that their sealant layers are in contact with each other and sealing them, or by folding a continuous (single) laminated laminate so that its sealant layers are in contact with each other and sealing it, or by arranging the laminated laminate and a thermoplastic resin film so that the sealant layer of the laminated laminate is in contact with the thermoplastic resin film and sealing it. The sealing method is not particularly limited, and may be heat sealing or ultrasonic sealing, or any known method. The packaging material can be suitably used as a package. Examples of such packaging include packaging for food such as Western confectionery, snacks, bread, Japanese confectionery, and seasonings, medical packaging for medicines, bandages, and syringes, and packaging for sanitary products such as dustcloths, masks, and brushes. The printed matter and laminate of the present invention and packaging materials using them are recyclable, and the recycled plastic can be used as recycled plastic.

[0156] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Hereinafter, "parts" and "%" are based on mass unless otherwise specified. Measurement of weight-average molecular weight (polystyrene equivalent) by GPC (gel permeation chromatography) in the present invention was carried out using an HLC8220 system manufactured by Tosoh Corporation under the following conditions: Separation column: Four TSKgel GMHHR-N columns manufactured by Tosoh Corporation. 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 B-type viscometer manufactured by Tokimec Inc.

[0157] 1. Measurement and Evaluation Methods Used in 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 number of milligrams of potassium hydroxide required to neutralize acetic acid bonded to hydroxyl groups when 1 g of a 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 free fatty acids, resin acids, etc. contained in 1 g of a sample, and was measured in accordance with JIS K 0070.

[0160] (Amine Value) The amine value is the amount of potassium hydroxide (mg) equivalent to the amount of hydrochloric acid required to neutralize the amino groups contained in 1 g of sample, and was measured in accordance with JIS K 0070. Specifically, 0.5 to 2 g of sample was precisely weighed (sample solids content: S g). 50 mL of a 60 / 40 (mass ratio) mixed solution of methanol and methyl ethyl ketone was added to the precisely weighed sample to dissolve it. Bromophenol blue was added as an indicator to the resulting solution, and the resulting solution was titrated with a 0.2 mol / L ethanolic hydrochloric acid solution (titer: f). The point at which the solution changed color from green to yellow was set as the endpoint, and the titration volume (A mL) at this point was used to calculate the amine value according to the following formula: (Formula) Amine value = (A × f × 0.2 × 56.108) / S [mg KOH / g]

[0161] (Cellophane tape adhesion) The viscosity of the ink compositions described in the Examples and Comparative Examples was adjusted with ethyl acetate to 16 seconds (25°C) using a Zahn cup #3 (manufactured by Rigo Co., Ltd.), and prints were produced using OPP film P2161 (20 μm) manufactured by Toyobo Co., Ltd., using a gravure proofing machine equipped with a gravure plate with a plate depth of 35 μm. After leaving the prints for one day, cellophane tape (manufactured by Nichiban, 12 mm wide) was applied to the printed surface and then quickly peeled off, and the appearance of the printed film was visually evaluated according to the following criteria: ○: No peeling of the printed film at all. ○ to △: 75 to 90% of the printed film remained on the film. △: 50 to 75% of the printed film remained on the film. ×: 50% or less of the printed film 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 to 16 seconds (25°C) using a Zahn cup #3 (manufactured by Rigo Co., Ltd.), and the ink compositions were printed using OPP film P2161 (20 μm) manufactured by Toyobo Co., Ltd., with the printed surface and non-printed surface of the film being in contact with each other using a gravure proofing machine equipped with a gravure plate with a plate depth of 35 μm. ２ After removal, the state of ink transfer to the non-printed side was visually evaluated using the following three-level scale: ○: Good, with 0-20% of the ink transferred to the non-printed side; △: Transfer of less than 50% was observed; ×: Transfer of less than 80% was observed.

[0163] (Extrusion Laminate (PEEL) Strength) The viscosity of the ink compositions described in the Examples and Comparative Examples was adjusted with ethyl acetate to 16 seconds (25°C) using a Zahn cup #3 (manufactured by Rigo Co., Ltd.), and a print was produced using an OPP film P2161 (20 μm) manufactured by Toyobo Co., Ltd., using a gravure proofing machine equipped with a gravure plate with a plate depth of 35 μm. A polyethyleneimine-based anchor coating agent was applied to this print at a concentration of 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, which was then cut into 15 mm widths and subjected to a 90-degree peel test (measurement of PEEL strength) at a pulling rate of 50 mm / min, and evaluated according to the following criteria: Good: PEEL strength is 1.5 to 2.0 N / 15 mm. Good to Fair: PEEL strength is 1.0 to 1.5 N / 15 mm. Fair: PEEL strength is 0.5 to 1.0 N / 15 mm. Bad: PEEL strength is less than 0.5 / 15 mm.

[0164] (Fluidity of mill base after milling) The viscosity of the liquid ink compositions described in the Examples and Comparative Examples was visually evaluated according to the following criteria: 5: smooth 4: slightly thick 3: thick 2: similar to stiff cream 1: not moving (no fluidity)

[0165] (Scratch Resistance) A printed ink laminate was formed using the liquid ink compositions obtained in the Examples and Comparative Examples with a gravure printing machine. The ink-coated surface of the printed ink laminate was then scratched with a fingernail, and the scratch resistance was visually evaluated based on the degree of damage to the coating film.

[0166] (Storage (Temporal) Stability (Sedimentation)) 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 observed at all. △: Some separation observed in the upper layer. A guideline is a separated layer of 5mm or less. ×: Obvious separation observed in the upper layer. A guideline is a separated layer of 5mm or more. <Sedimentation> Slowly scrape the bottom of the container in which the ink was stored with a spatula. ◯: No sediment observed at all. △: A slight amount of sediment observed at the bottom. (A small amount of sediment can be seen at the tip of the spatula) ×: A large amount of sediment observed at the bottom. (A large amount of sediment can be scraped off with the 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 (I-a) 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 into a four-neck flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, and the mixture was 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 to prepare a homogeneous solution of the urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture of 0.10 parts of dibutylamine, 5.95 parts of isophoronediamine, 101.35 parts of ethyl acetate, and 81.55 parts of isopropyl alcohol, and the mixture was stirred and reacted at 45°C for 5 hours to obtain urethane resin solution (Ia). The obtained urethane resin solution (Ia) had a resin solids concentration of 30% by weight and a urethane bond concentration of 1.38 mmol / g calculated by the above-mentioned method.

[0168] (2-1.2) Synthesis of urethane resin (I-b) A four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube was charged with 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, and the mixture was reacted for 15 hours at 90 ° C. under a nitrogen stream to produce a urethane prepolymer having an isocyanate group, and then 50.1 parts of ethyl acetate was added to the mixture to obtain a homogeneous solution of urethane prepolymer. Next, 0.10 parts of dibutylamine, 5.95 parts of isophorone diamine, 101.35 parts of ethyl acetate, and 81.55 parts of isopropyl alcohol were added to the urethane prepolymer solution, and the mixture was stirred and reacted at 45 ° C. for 5 hours to obtain a urethane resin solution (I-b). The resulting urethane resin solution (Ib) had a resin solid concentration of 30% by weight and a urethane bond concentration of 1.30 mmol / g as calculated by the above-mentioned method.

[0169] (2-1.3) Synthesis of Urethane Resin (I-c) A four-neck flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube was charged with 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, and the mixture was reacted at 90°C for 15 hours under a nitrogen stream to produce a urethane prepolymer having isocyanate groups. To this was added 50.1 parts of ethyl acetate to obtain a homogeneous solution of the urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture of 0.10 parts of dibutylamine, 5.95 parts of isophoronediamine, 101.35 parts of ethyl acetate, and 81.55 parts of isopropyl alcohol, and the mixture was stirred and reacted at 45°C for 5 hours to obtain urethane resin solution (I-c). The obtained urethane resin solution (I-c) had a resin solids concentration of 30% by weight and a urethane bond concentration of 1.10 mmol / g calculated by the above-mentioned method.

[0170] (2-1.4) Synthesis of Urethane Resin (I-d) A four-neck flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube was charged with 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, and the mixture was reacted at 90°C for 15 hours under a nitrogen stream to produce a urethane prepolymer having isocyanate groups. To this was added 50.1 parts of ethyl acetate to obtain a homogeneous solution of the urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture of 0.10 parts of dibutylamine, 5.95 parts of isophoronediamine, 101.35 parts of ethyl acetate, and 81.55 parts of isopropyl alcohol, and the mixture was stirred and reacted at 45°C for 5 hours to obtain urethane resin solution (I-d). The obtained urethane resin solution (I-d) had a resin solids concentration of 30% by weight and a urethane bond concentration of 1.29 mmol / g, calculated by the above-mentioned method.

[0171] (2-1.5) Synthesis of Urethane Resin (I-e) A four-neck flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube was charged with 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, and the mixture was reacted at 90°C for 15 hours under a nitrogen stream to produce a urethane prepolymer having isocyanate groups. To this was added 50.1 parts of ethyl acetate to obtain a homogeneous solution of the urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture of 0.10 parts of dibutylamine, 5.95 parts of isophoronediamine, 101.35 parts of ethyl acetate, and 81.55 parts of isopropyl alcohol, and the mixture was stirred and reacted at 45°C for 5 hours to obtain urethane resin solution (I-e). The obtained urethane resin solution (I-e) had a resin solids concentration of 30% by weight and a urethane bond concentration of 1.30 mmol / g calculated by the above-mentioned method.

[0172] (2-1.6) Synthesis of urethane resin (If) A four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube was charged with 59.11 parts of neopentyl glycol adipate diol (hydroxyl value: 56.0 mg KOH / g) and 14.78 parts of polycarbonate (1) (hydroxyl value: 216.4 mg KOH / g) and 20.06 parts of isophorone diisocyanate, and the mixture was reacted for 15 hours at 90 ° C. under a nitrogen stream to produce a urethane prepolymer having an isocyanate group. 50.1 parts of ethyl acetate was added to this to obtain a homogeneous solution of urethane prepolymer. Next, a mixture 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 was added to the urethane prepolymer solution, and the mixture was stirred and reacted at 45 ° C. for 5 hours to obtain a urethane resin solution (If). The resulting urethane resin solution (If) had a resin solid concentration of 30% by weight and a urethane bond concentration of 1.16 mmol / g calculated by the above-mentioned method.

[0173] (2-1.7) Synthesis of urethane resin (I-g) A four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube was charged with 59.21 parts of neopentyl glycol adipate diol (hydroxyl value: 56.0 mg KOH / g) and 14.80 parts of polypropylene glycol (2) (hydroxyl value: 280.0 mg KOH / g) and 22.15 parts of isophorone diisocyanate, and the mixture was reacted for 15 hours at 90 ° C. under a nitrogen stream to produce a urethane prepolymer having an isocyanate group. 50.1 parts of ethyl acetate was then added to the mixture to obtain a homogeneous solution of the urethane prepolymer. Next, 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. The urethane prepolymer solution was added and the mixture was stirred and reacted at 45 ° C. for 5 hours to obtain a urethane resin solution (I-g). The resulting urethane resin solution (Ig) had a resin solid concentration of 30% by weight and a urethane bond concentration of 1.33 mmol / g as calculated by the above method.

[0174] (2-1.8) Synthesis of Urethane Resin (I-h) 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 into a four-neck flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, and the mixture was reacted at 90°C for 15 hours under a nitrogen stream to produce a urethane prepolymer having an isocyanate group. 50.1 parts of ethyl acetate was then added to the mixture. A homogeneous solution of urethane prepolymer was obtained. 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 and reacted at 45°C for 5 hours to obtain urethane resin solution (I-h). The obtained urethane resin solution (I-h) had a resin solids concentration of 30% by weight and a urethane bond concentration of 0.91 mmol / g, calculated by the above-mentioned method.

[0175] (2-1.9) Synthesis of Urethane Resin (I-i) A four-neck flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube was charged with 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, and the mixture was reacted at 90°C for 15 hours under a nitrogen stream to produce a urethane prepolymer having isocyanate groups. To this was added 50.1 parts of ethyl acetate to obtain a homogeneous solution of the urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture of 0.74 parts of dibutylamine, 4.41 parts of isophoronediamine, 1.47 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 and reacted at 45°C for 5 hours to obtain urethane resin solution (I-i). The obtained urethane resin solution (I-i) had a resin solids concentration of 30% by weight and a urethane bond concentration of 0.96 mmol / g calculated by the above-mentioned method.

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

[0177] (2-1.11) Synthesis of urethane resin (I-k) A four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube was charged with 69.16 parts of neopentyl glycol adipate diol (hydroxyl value: 56.0 mg KOH / g) and 5.28 parts of polypropylene glycol (1) (hydroxyl value: 445.0 mg KOH / g) and 19.51 parts of isophorone diisocyanate, and the mixture was reacted for 15 hours at 90 ° C. under a nitrogen stream to produce a urethane prepolymer having an isocyanate group. 50.1 parts of ethyl acetate was added to this to obtain a homogeneous solution of urethane prepolymer. Next, a mixture 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 was added to the urethane prepolymer solution, and the mixture was stirred and reacted at 45 ° C. for 5 hours to obtain a urethane resin solution (I-k). The resulting urethane resin solution (Ik) had a resin solid concentration of 30% by weight and a urethane bond concentration of 1.11 mmol / g calculated by the above-mentioned method.

[0178] (2-1.12 to 2-1.17) Synthesis of Urethane Resins (I-l) to (I-q) Using the raw materials listed in Table 1-3, urethane resins (I-l) to (I-q) were synthesized by the same method as for urethane resins (I-a) to (I-k). The resulting urethane resin solutions (I-l) to (I-q) all had a resin solids concentration of 30% by weight. The tolylene diisocyanate used in the synthesis of urethane resins (I-l) to (I-p) was Cosmonate T-80 manufactured by Mitsui Chemicals, Inc. The diphenylmethane diisocyanate used in the synthesis of urethane resin (I-q) was Millionate NM manufactured by Tosoh Corporation.

[0179] (2-2) Synthesis of Urethane Resin (II) (2-2.1) Synthesis of Urethane Resin (II-1) A four-neck flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube was charged with 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, and the mixture was reacted at 90°C for 15 hours under a nitrogen stream to produce a urethane prepolymer having an isocyanate group. To this was added 50.1 parts of ethyl acetate to obtain a homogeneous solution of the urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture of 0.10 parts of dibutylamine, 5.95 parts of isophoronediamine, 101.35 parts of ethyl acetate, and 81.55 parts of isopropyl alcohol, and the mixture was stirred and reacted at 45°C for 5 hours to obtain urethane resin solution (II-1). The resulting urethane resin solution (II-1) had a resin solids concentration of 30% by weight and a urethane bond concentration of 1.68 mmol / g calculated by the above-mentioned method.

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

[0181] (2-2.3) Synthesis of Urethane Resin (II-3) A four-neck flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube was charged with 351.5 parts of hydrogenated ketone-aldehyde resin (TEGO (registered trademark) Varipuls SK number average molecular weight 800, hydroxyl value 325 mg KOH / g, manufactured by EVONIK Corporation), 48.5 parts of isophorone diisocyanate, and 400 parts of ethyl acetate, and the mixture was reacted at 90°C for 6 hours under a nitrogen stream to obtain Urethane Resin (II-3) with a solids 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]

[0183]

[0184]

[0185] Urethane resins (I-a) to (I-q) and urethane resins (II-1) to (II-3) were synthesized according to the composition ratios shown in Tables 1-1, 1-2, and 1-3. The urethane bond concentration and number average molecular weight (Mn) were measured using the methods described above. The results are shown in Tables 1-1, 1-2, and 1-3.

[0186] In addition, 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): NOF Corporation's "Uniol D-250" (number average molecular weight 250) Polypropylene glycol (2): NOF Corporation's "Uniol D-400G" (number average molecular weight 400) Polypropylene glycol (3): NOF Corporation's "Uniol D-700" (number average molecular weight 700) Polypropylene glycol (4): NOF Corporation's "Uniol D-1000" (number average molecular weight 1000)

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

[0188] (2-2) Preparation of Liquid Ink Composition Example 1 A mixture of 15 parts by mass of a polyvinyl butyral resin-containing solution (polyvinyl butyral resin, 10% by mass solids), 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% by mass solids) of the urethane resin (I-a) obtained above and 10 parts by mass of propyl acetate were added to prepare a blue printing ink composition (1) (hereinafter also referred to as composition (1)) as a liquid ink composition. The base adsorption amount per surface area of ​​the phthalocyanine blue pigment (FASTGEN Blue LA5380, manufactured by DIC Corporation) was 0.0 μmol / m ２ It was.

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

[0190] Comparative Examples 1 to 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 using the compositions and composition ratios shown in Tables 2-1 and 2-2 below, in the same manner as in Example 1. The comparative compositions (1) to (6) obtained in Comparative Examples 1 to 6 above were subjected to the various evaluations described above.

[0191]

[0192]

[0193] In Tables 2-1 to 2-3 above, the easily dispersible pigment Blue 15:3 used was a pigment obtained by the following method. 373.1 parts of C.I. Pigment Blue 15:3 (manufactured by DIC Corporation) wet cake (150 parts pigment) and 500 parts of ion-exchanged water were placed in a 2 L stainless steel cup and stirred for 15 minutes using a Homodisper 2.5 model (manufactured by Primix Corporation) at a rotation speed of 500 rpm. The C.I. Pigment Blue 15:3 slurry was transferred to a 5 L stainless steel cup, 2127 parts of ion-exchanged water was 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.) was added and dissolved, and the temperature was raised to 60°C. Subsequently, 54 parts of 35% hydrogen peroxide water (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) was added and stirred for 2 hours. The slurry was then filtered through a Nutsche filter and washed with 12 L of 70°C hot water. The residue was then air-dried (98°C, 18 hours) using a WFO-500 constant temperature air-blowing dryer (manufactured by Tokyo Rikakikai Co., Ltd.). The resulting pigment mass was pulverized to obtain 150 parts of copper phthalocyanine pigment (PB15:3). The amount of iron contained in the pigment was 3530 ppm. The amount of base adsorption per surface area of ​​the pigment was 0.57 μmol / m ２In this example, the amount of iron element contained in the pigment was measured using an energy dispersive X-ray fluorescence analyzer PANalytical Epsilon 5 (manufactured by Spectris Co., Ltd.). In this example, the amount of base adsorption per 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 together with 15 mL of base solution for adsorption, and the mixture was mixed and stirred (750 cpm, 15 minutes) using a paint shaker (manufactured by Toyo Seiki Seisaku-sho, Ltd.). Subsequently, the mixture was centrifuged (3500 G, 20 minutes) using a refrigerated high-speed centrifuge H-2000B (manufactured by Kokusan Co., Ltd.) to settle the pigment, and 10 mL of the supernatant solution was then collected. The supernatant solution was diluted with 15 mL of n-propyl acetate (Kanto Chemical Co., Inc.), and potentiometric titration was performed with a titration acid solution using an automatic titrator COM-A19 (HIRANUMA Corporation) to measure the amount of unadsorbed base present in the supernatant solution. The amount of unadsorbed base was calculated by subtracting the amount of base added from the amount of base found. The amount of base adsorption per pigment surface area was then calculated by dividing the amount of base adsorption per weight by the nitrogen adsorption specific surface area. The base solution for adsorption was prepared by diluting a 0.1 mol / L tetra-n-butylammonium hydroxide solution (N / 10) (benzene / methanol solution) (Kanto Chemical Co., Inc.) with a known factor value to exactly 1 / 100 with n-propyl acetate (Kanto Chemical Co., Inc.). The acid solution for titration was prepared by dissolving approximately 95 mg of p-toluenesulfonic acid monohydrate (manufactured by Kanto Chemical Co., Ltd.) in 500 mL of n-propyl acetate (manufactured by Kanto Chemical Co., Ltd.), and the concentration was titrated with the above-mentioned base solution for adsorption before use.

[0194] The experimental results in Tables 2-1, 2-2, and 2-3 above confirm that the ink compositions of Examples 1 to 34 were all capable of forming ink layers superior in blocking resistance, adhesion, and lamination suitability compared to the ink compositions of the comparative examples. Furthermore, the evaluation results for storage (aging) stability separation, which is an index of pigment dispersibility for the ink compositions of Examples 1 to 34, were either "no separation observed" or "a layer of 5 mm or less in thickness was observed in the slightly upper layer." The evaluation results for precipitation for the ink compositions of Examples 1 to 34 were either "no separation observed" or "slight precipitation observed at the bottom (a small amount of precipitate was observed at the tip of a spatula)." The millbase fluidity after grinding for the ink compositions of Examples 1 to 34 was either "5" or "4." Furthermore, the scratch resistance test results confirmed that the ink layers formed from the ink compositions of Examples 1 to 34 were free of scratches or only slightly scratched. This is thought to be due to the high urethane bond concentration of 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 capable of forming ink layers that have an excellent balance of scratch resistance, pigment dispersibility, and fluidity and storage (aging) stability.

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

Claims

1. A liquid ink composition comprising at least a urethane resin component and an organic solvent, the urethane resin component containing at least a urethane resin (I) having as reaction raw materials (1) a polycarbonate or a polyoxyalkylene compound having a structural 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.

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

3. 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.

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

5. The liquid ink composition according to claim 4, wherein at least one of the urethane resin (I) and the urethane resin (II) has a urethane bond concentration of 0.98 mmol / g or more.

6. The liquid ink composition according to claim 4, wherein at least one of the urethane resin (I) and the urethane resin (II) contains a polyester polyol as a reactive raw material.

7. A liquid ink composition according to claim 4, wherein the total amount of the urethane resin (I) and the urethane resin (II) among the resin components contained in the liquid ink composition is 30 to 100 mass % based on the total resin solid content of the liquid ink composition.

8. The liquid ink composition according to claim 1, which contains at least one resin selected from the group consisting of polyvinyl butyral resins, maleic acid resins, cellulose resins, polyester resins, acrylic resins and polyamide resins.

9. The composition further comprises a pigment, and the pigment has a base adsorption amount per surface area of ​​the pigment of 0.30 μmol / m ２ The liquid ink composition according to claim 1 .

10. The liquid ink composition according to claim 1, further comprising a pigment, said pigment containing 200 ppm or more of elemental iron per 100 parts by mass of the pigment.

11. A printed matter obtained by printing the ink composition according to any one of claims 1 to 10 on a substrate.

12. A laminate or package comprising the printed matter according to claim 11.

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