Inkjet ink and inkjet recording method

Abstract

Provided are: an inkjet ink which is capable of obtaining an image recording material that has excellent invisibility and can maintain infrared absorption capacity for a longer period of time than in the past; and an application of the inkjet ink. The inkjet ink contains a dye compound represented by formula 1, a dispersant, a water-soluble organic solvent, and water, wherein the dispersant is a polymer containing an acidic functional group and an ethylene oxide chain. In formula 1, T1, T2, R1, R2, X1, and n are not explained. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to an inkjet ink and an inkjet recording method. Background Art

[0002] In recent years, it has been proposed to expand near-infrared absorbing pigments to various uses that utilize their characteristics. For example, near-infrared absorbing pigments are used in optical films such as infrared cutoff filters and heat ray shielding films for plasma displays or CCDs (imaging elements); photothermal conversion materials for write-once optical discs or flash fusing materials; information display materials such as anti-counterfeiting inks and invisible barcode inks; and medical materials such as diagnostic markers and photodynamic therapy agents. As a unique performance of near-infrared absorbing pigments, it is required to have strong absorption in the near-infrared region or infrared region while having as little absorption as possible in the visible light region (invisibility). In addition, it is also required to maintain infrared absorption ability for a long time.

[0003] For example, Patent Document 1 describes an inkjet recording ink containing a specific cyanine pigment and a medium.

[0004] Patent Document 2 describes a near infrared absorbing composition containing at least one selected from the group consisting of a squarylium cyanine dye, a resin, a dispersant, an organic solvent, and water.

[0005] Patent document 3 describes a UV-curable non-aqueous inkjet ink, which includes a monomer solvent containing a donor monomer and an acceptor monomer, a pigment and a polymer dispersant, and does not contain water. Polymerization is carried out through the charge density difference between the donor monomer and the acceptor monomer. In the non-aqueous inkjet ink, the polymer dispersant has a comb-type structure including a main chain and side chains bonded to the main chain, and the difference between the SP value of the polymer dispersant and the SP value of the monomer solvent is less than 1.6.

[0006] Patent Document 1: International Publication No. 2022 / 049862

[0007] Patent Document 2: Japanese Patent Application Publication No. 2019-001983

[0008] Patent Document 3: Japanese Patent Application Publication No. 2013-129746

[0009] Near-infrared absorbing dyes are required to have excellent invisibility and to maintain infrared absorbing ability for a longer period of time than before. Summary of the invention

[0010] The present invention has been made in view of such circumstances, and an object of one embodiment of the present invention is to provide an inkjet ink and an inkjet recording method capable of obtaining an image record having excellent invisibility and maintaining infrared absorption capability for a longer period than before.

[0011] The present invention includes the following aspects.

[0012] <1>

[0013] An inkjet ink comprising a pigment compound represented by the following formula 1, a dispersant, a water-soluble organic solvent and water, wherein the dispersant is a polymer comprising an acidic functional group and an ethylene oxide chain.

[0014] [Chemical formula 1]

[0015]

[0016] In formula 1, L 1 Represents a methine chain consisting of an odd number of methines. 1 and R 2 Each independently represents an aliphatic group or an aromatic group. 1 and T 2 Each independently represents a non-metallic atom group forming a 5-membered or 6-membered nitrogen-containing heterocyclic ring which may be fused, Cy is an anion part, and X 1 represents an organic cation represented by the following formula 2-1, formula 2-2 or formula 2-3 or an organic cation having a structure represented by formula 2-4, n is a non-zero number required for neutralizing charges,

[0017] [Chemical formula 2]

[0018]

[0019] [Chemical formula 3]

[0020]

[0021] [Chemical formula 4]

[0022]

[0023] [Chemical formula 5]

[0024]

[0025] In formula 2-1, A 11 and A 12 Each independently represents a nitrogen atom or a phosphorus atom, and B 11 Each independently represents a divalent linking group, R 1a , R 1b , R 1c , R1d 、E 11 and E 12 Each independently represents an aliphatic group or an aromatic group, R 1a , R 1b , R 1c and R 1d may be bonded to each other to form a ring, m1 is an integer greater than 1,

[0026] In formula 2-2, A 21 , A 22 and A 23 Each independently represents a nitrogen atom or a phosphorus atom, and B 21 and B 22 Each independently represents a divalent linking group, R 2a and R 2b Each independently represents an aliphatic group or an aromatic group, m2 is an integer greater than 0, G 21 Indicates that the ring contains A 21 The non-metallic atom group of the aromatic ring, G 22 Indicates that the ring contains A 23 The aromatic ring of the non-metallic atom group,

[0027] In formula 2-3, A 31 and A 32 Each independently represents a nitrogen atom or a phosphorus atom, and B 31 represents a divalent linking group, R 3a and R 3b Each independently represents an aliphatic group or an aromatic group, G 31 Indicates that the ring contains A 31 The non-metallic atom group of the aromatic ring, G 32 Indicates that the ring contains A 32 The aromatic ring of the non-metallic atom group,

[0028] In formula 2-4, A 41 Each independently represents a nitrogen atom or a phosphorus atom, and B 41 Each independently represents a single bond or a divalent linking group, R 4a , R 4b and R 4c Each independently represents an aliphatic group or an aromatic group, and E 41 and E 42 Each independently represents a single bond or an aliphatic group, R 4a , R 4b and R 4c One of them can be combined with E 41 or E 42 They are bonded to form a ring, and m4 is an integer greater than or equal to 2.

[0029] <2>

[0030] The inkjet ink according to <1>, wherein the dispersant further includes a structural unit derived from at least one selected from the group consisting of styrene and styrene derivatives.

[0031] <3>

[0032] The inkjet ink according to <1> or <2>, wherein the content of the structural unit derived from at least one selected from the group consisting of styrene and styrene derivatives is 1 mol % to 60 mol % based on the total amount of the dispersant.

[0033] <4>

[0034] The inkjet ink according to any one of <1> to <3>, wherein a mass ratio of a content of the dispersant to a content of the pigment compound represented by Formula 1 is 0.1 to 3.

[0035] <5>

[0036] The inkjet ink according to any one of <1> to <4>, wherein the SP value of the mixed solvent composed of water and the water-soluble organic solvent is 40.0 MPa 1 / 2 above.

[0037] <6>

[0038] The inkjet ink according to any one of <1> to <5>, wherein when the SP value of the water-soluble organic solvent is A [MPa 1 / 2 ], when the ratio of the water-soluble organic solvent to the total content of water and the water-soluble organic solvent is set to B mass %, A and B satisfy the following formula T1,

[0039] 10≤B≤1.6×A-7…(T1).

[0040] <7>

[0041] The inkjet ink according to <6>, wherein A and B satisfy the following formula T2.

[0042] 10≤B≤1.6×A-12……(T2)

[0043] <8>

[0044] The inkjet ink according to any one of <1> to <7>, wherein the content of the water-soluble organic solvent is 15% by mass to 35% by mass based on the total content of water and the water-soluble organic solvent.

[0045] <9>

[0046] The inkjet ink according to any one of <1> to <8>, wherein in Formula 1, Cy is represented by Formula 4 below.

[0047] [Chemical formula 6]

[0048]

[0049] In formula 4, Y 1 and Y 2 Represent CR independently 3 R 4 -, -O-, -S-, -Se-, or -NR 5 -. R 3 , R 4 and R 5 R each independently represents a hydrogen atom, an aliphatic group or an aromatic ring group. 3 and R 4 They may be bonded to each other to form a ring. 1 and A 2 Each independently represents a non-metallic atom group forming an aromatic ring or an aromatic heterocyclic ring. 2 Each independently represents a methine chain consisting of 1, 2 or 3 methine groups, L 2 It has no substituent. 6 and R 7 R each independently represents a hydrogen atom or an aliphatic group. 6 and R 7 Can be linked to each other to form a ring. 8 It is represented by the following formula A.

[0050] -S A -T A Formula A

[0051] In formula A, S A represents a single bond, alkylene, alkenylene, alkynylene, -O-, -S-, -NR L1 -, -C(=O)-, -C(=O)O-, -C(=O)NR L1 -、-S(=O)2-、-OR L2 - or a group consisting of at least two of these, R L1 Each independently represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group or a monovalent heterocyclic group, and R L2 represents an alkylene group, an arylene group or a divalent heterocyclic group, T A represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, a monovalent heterocyclic group, a cyano group, a hydroxyl group, a formyl group, a carboxyl group, an amino group, a thiol group, a sulfone group, a phosphoryl group, a boryl group, a vinyl group, an ethynyl group, a trialkylsilyl group or a trialkoxysilyl group.

[0052] <10>

[0053] An inkjet recording method comprising the step of applying the inkjet ink described in any one of <1> to <9> to a substrate by inkjet recording.

[0054] Effects of the Invention

[0055] According to the present invention, it is possible to provide an inkjet ink and an inkjet recording method capable of obtaining an image recorded material having excellent invisibility and maintaining infrared absorption capability for a longer period of time than before. DETAILED DESCRIPTION

[0056] Hereinafter, the inkjet ink and the inkjet recording method of the present invention will be described in detail.

[0057] In the present specification, a numerical range expressed using "to" indicates a range including the numerical values ​​described before and after "to" as the minimum value and the maximum value, respectively.

[0058] In the numerical ranges recorded in this specification, the upper limit or lower limit recorded in a certain numerical range can be replaced by the upper limit or lower limit of other numerical ranges recorded in other stages. In addition, in the numerical ranges recorded in this specification, the upper limit or lower limit recorded in a certain numerical range can also be replaced by the value shown in the embodiments.

[0059] In the present specification, when a plurality of substances corresponding to each component are present in the composition, the amount of each component in the composition means the total amount of the plurality of substances present in the composition unless otherwise specified.

[0060] In the present specification, a combination of two or more preferred aspects is a more preferred aspect.

[0061] In the present specification, the term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes as long as the intended purpose of the process can be achieved.

[0062] In this specification, "(meth)acrylate" is a concept including both acrylate and methacrylate. Also, "(meth)acrylic acid" is a concept including both acrylic acid and methacrylic acid.

[0063] In the present specification, a monovalent heterocyclic group refers to a group formed by removing one hydrogen atom from a heterocyclic compound, and a divalent heterocyclic group refers to a group formed by removing two hydrogen atoms from a heterocyclic compound.

[0064] <<Inkjet ink>>

[0065] The inkjet ink of the present invention comprises a pigment compound represented by Formula 1 described below, a dispersant, a water-soluble organic solvent and water, wherein the dispersant is a polymer comprising an acidic functional group and an ethylene oxide chain.

[0066] The pigment compound represented by Formula 1 has excellent infrared absorption ability and little absorption in the visible region, and thus has excellent invisibility. In addition, the infrared absorption ability of the pigment compound represented by Formula 1 can be maintained for a longer period of time than before.

[0067] The pigment compound represented by formula 1 is cyanine pigment, and cyanine pigment easily forms an associated complex. When cyanine pigment forms an associated complex, it absorbs light of long wavelength, so it is excellent in invisibility and has excellent durability such as light resistance, resistance to moisture and heat. As described later, the pigment compound represented by formula 1 has a cyanine pigment structure and an organic cation represented by formula 2-1, formula 2-2 or formula 2-3 or an organic cation with a structure represented by formula 2-4. These organic cations have a soft molecular structure, so it is inferred that the effect of linking cyanine pigments to each other at the position where an associated complex can be properly formed is high. It is believed that the ability to form an associated complex of the pigment compound represented by formula 1 is high, so the infrared absorption ability of the inkjet ink comprising the pigment compound represented by formula 1 can be maintained for a longer time than in the past.

[0068] The present inventors have found that the formation of anthocyanin complexes is easily affected by the polarity and acid-base properties of the medium in which the anthocyanin is dispersed. Furthermore, the present inventors have found that by making the inkjet ink contain a specific dispersant, the formed complexes can be made more stable, thereby maintaining the infrared absorption capacity for a longer period of time.

[0069] In the present invention, the mechanism by which the above-mentioned effects can be obtained is not yet clear, but is presumed to be as follows.

[0070] First, when the dispersant contains ethylene oxide chains, the hydrophobic interaction between the ethylene oxide chains and the pigment compound represented by Formula 1 improves the wettability of the pigment compound represented by Formula 1 to the dispersion medium (water and a water-soluble organic solvent).

[0071] It is believed that by the dispersant containing an acidic functional group, the cations dissociated from the dispersant contribute to the formation of the associate.

[0072] Furthermore, it is considered that, when the dispersant contains an oxyethylene chain, the hydrophobic interaction between the oxyethylene chain and the pigment compound represented by Formula 1 stabilizes the formed association.

[0073] By stabilizing the association, the infrared absorption capability can be maintained for a longer period of time.

[0074] In contrast, there is no description focusing on the dispersant in Patent Document 1. Furthermore, there is no description of the pigment compound represented by Formula 1 in Patent Documents 2 and 3. There is no description of the contribution of the dispersant contained in the inkjet ink of the present invention to the formation of the association complex in Patent Documents 1 to 3.

[0075] Hereinafter, each component contained in the inkjet ink (hereinafter, also simply referred to as "ink") of the present invention is described.

[0076] <Dye compound represented by formula 1>

[0077] The ink of the present invention includes a pigment compound represented by Formula 1.

[0078] [Chemical formula 7]

[0079]

[0080] In formula 1, L 1 Represents a methine chain consisting of an odd number of methines. 1 and R 2 Each independently represents an aliphatic group or an aromatic group. 1 and T 2 Each independently represents a non-metallic atom group forming a 5-membered or 6-membered nitrogen-containing heterocyclic ring which may be fused, Cy is an anion part, and X 1 represents an organic cation represented by the following formula 2-1, formula 2-2 or formula 2-3 or an organic cation having a structure represented by formula 2-4, n is a non-zero number required for neutralizing charges,

[0081] [L 1 ]

[0082] In formula 1, L 1 Represents a methine chain consisting of an odd number of methines. 1 It preferably represents a methine chain consisting of 5, 7 or 9 methine groups, and more preferably represents a methine chain consisting of 5 or 7 methine groups.

[0083] The central methine group of the methine chain preferably has a substituent represented by Formula A. A and T A , which will be explained later.

[0084] *-S A -T A Formula A

[0085] The methine groups other than the central methine group in the methine chain may have a substituent, but preferably have no substituent.

[0086] The methine chain may have a cross-linked structure at any position. For example, in the methine chain, the carbon atoms constituting the methine chain may bond to each other to form a ring structure. The ring structure is not particularly limited, and is preferably an aliphatic ring, more preferably a 5-membered aliphatic ring or a 6-membered aliphatic ring.

[0087] Specifically, L 1It is preferably a group represented by the following formula L1-1, L1-2, L2-1 or L2-2, and more preferably a group represented by the following formula L1-2 or L2-2.

[0088] [Chemical formula 8]

[0089]

[0090] In formula L1-1, formula L1-2, formula L2-1 and formula L2-2, A represents a substituent represented by the above formula A, and the wavy line portion independently represents the substituent corresponding to L in formula 1. 1 Bonding positions of structures other than .

[0091] In formula L2-1 and formula L2-2, Y L Y represents a non-metallic atom group forming an aliphatic ring or a heterocyclic ring, and preferably represents a non-metallic atom group forming an aliphatic ring. L Preferably, it is an alkylene group, and examples of the alkylene group include -CH2CH2- and -CH2C(Z)2-CH2-. The aliphatic ring is preferably a 5-membered aliphatic ring or a 6-membered aliphatic ring. Z each independently represents a hydrogen atom or an alkyl group. Z is preferably a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and more preferably a hydrogen atom or a methyl group. Two Zs may be bonded to form a ring structure.

[0092] The group represented by the above formula L2-1 or L2-2 is preferably a group represented by the following formula L3-1 to formula L3-4.

[0093] [Chemical formula 9]

[0094]

[0095] In formula L3-3 and formula L3-4, Z each independently represents a hydrogen atom or an alkyl group. Z is preferably a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and more preferably a hydrogen atom or a methyl group. Two Zs may be bonded to form a ring structure.

[0096] In formula L3-1 to formula L3-4, A represents a substituent represented by the above formula A, and the wavy line portion independently represents the substituent corresponding to L in formula 1. 1 Bonding positions of structures other than .

[0097] In formula A, S A represents a single bond, alkylene, alkenylene, alkynylene, -O-, -S-, -NR L1 -, -C(=O)-, -C(=O)O-, -C(=O)NR L1 -、-S(=O)2-、-OR L2 - or a group consisting of at least two of these. From the perspective of invisibility, S AIt is preferably a single bond, an alkylene group, an alkenylene group or an alkynylene group, and more preferably a single bond.

[0098] The alkylene group is preferably an alkylene group having 1 to 10 carbon atoms, more preferably an alkylene group having 1 to 4 carbon atoms, and further preferably a methylene group or a vinyl group.

[0099] The alkenylene group is preferably an alkenylene group having 2 to 10 carbon atoms, more preferably an alkenylene group having 2 to 4 carbon atoms, and further preferably an alkenylene group having 2 or 3 carbon atoms.

[0100] The alkynylene group is preferably an alkynylene group having 2 to 10 carbon atoms, more preferably an alkynylene group having 2 to 4 carbon atoms, and further preferably an alkynylene group having 2 or 3 carbon atoms.

[0101] The alkylene group, alkenylene group and alkynylene group may be linear or branched, and a part or all of the carbon atoms contained in each group may form a ring structure.

[0102] Hereinafter, in the description of the alkylene group, alkenylene group and alkynylene group in the present invention, the above contents apply unless otherwise specified.

[0103] In -C(=O)O-, the carbon atom and L 1 Bonded and oxygen atoms with T A bond, or it can be an oxygen atom and L 1 Bonded and carbon atoms with T A Bond.

[0104] -C(=O)NR L1 - can be carbon atoms and L 1 Bonded and nitrogen atom with T A Bonding, or nitrogen atom and L 1 Bonded and carbon atoms with T A Bond.

[0105] In formula A, when S A For-NR L1 -or-C(=O)NR L1 -, R L1 It represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group or a monovalent heterocyclic group, and is preferably a hydrogen atom, an alkyl group or an aryl group, and more preferably a hydrogen atom.

[0106] Examples of the halogen atom include a fluorine atom (F atom), a chlorine atom (Cl atom), a bromine atom (Br atom) and an iodine atom (I atom). Among them, the halogen atom is preferably a Cl atom or a Br atom, and more preferably a Cl atom.

[0107] The alkyl group is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, and further preferably an alkyl group having 1 or 2 carbon atoms.

[0108] The aryl group is preferably an aryl group having 6 to 20 carbon atoms, and more preferably a phenyl group or a naphthyl group.

[0109] The heterocyclic ring in the monovalent heterocyclic group is preferably a 5-membered ring or a 6-membered ring. In addition, the heterocyclic ring may form a condensed ring with an aliphatic ring, an aromatic ring or other heterocyclic ring. As the heteroatom in the heterocyclic ring, N atom, O atom and S atom may be mentioned, preferably N atom.

[0110] Examples of the heterocyclic ring include a pyridine ring, a piperidine ring, a furan ring, a furfuran ring, a thiophene ring, a pyrrole ring, a quinoline ring, a morpholine ring, an indole ring, an imidazole ring, a pyrazole ring, a carbazole ring, a phenothiazine ring, a phenoxazine ring, an indoleline ring, a pyrrolidone ring, a thiazole ring, a pyrazine ring, a thiadiazine ring, a benzoquinoline ring and a thiadiazole ring.

[0111] In formula A, when S A For-OR L2 -, R L2 represents an alkylene group, an arylene group or a divalent heterocyclic group, and is preferably an alkylene group.

[0112] The alkylene group is preferably an alkylene group having 1 to 10 carbon atoms, more preferably an alkylene group having 1 to 4 carbon atoms, and further preferably an alkylene group having 1 or 2 carbon atoms.

[0113] The arylene group is preferably an arylene group having 6 to 20 carbon atoms, more preferably a phenylene group or a naphthylene group, and further preferably a phenylene group.

[0114] The divalent heterocyclic group is preferably selected from the group consisting of R L1 A structure obtained by further removing one hydrogen from the monovalent heterocyclic group in .

[0115] In formula A, T A represents a halogen atom, an alkyl group, an aryl group, a monovalent heterocyclic group, a cyano group, a hydroxyl group, a formyl group, a carboxyl group, an amino group, a thiol group, a sulfo group, a phosphoryl group, a boryl group, a vinyl group, an ethynyl group, a trialkylsilyl group or a trialkoxysilyl group. A It is preferably an aryl group, a monovalent heterocyclic group or a trialkylsilyl group.

[0116] Examples of the halogen atom include a fluorine atom (F atom), a chlorine atom (Cl atom), a bromine atom (Br atom) and an iodine atom (I atom). Among them, the halogen atom is preferably a Cl atom or a Br atom, and more preferably a Cl atom.

[0117] The alkyl group is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, and further preferably an alkyl group having 1 or 2 carbon atoms.

[0118] In formula A, when T A When T represents an alkyl group, AIt can form a ring structure with other carbon atoms in the methine chain. As the ring structure, a 5-membered ring or a 6-membered ring is preferred.

[0119] The aryl group is preferably an aryl group having 6 to 20 carbon atoms, more preferably a phenyl group or a naphthyl group, and further preferably a phenyl group.

[0120] The heterocyclic ring in the monovalent heterocyclic group is preferably a 5-membered ring or a 6-membered ring. Furthermore, the heterocyclic ring may form a condensed ring with an aliphatic ring, an aromatic ring or another heterocyclic ring.

[0121] Examples of the hetero atom in the heterocyclic ring include a N atom, an O atom and a S atom, and a N atom is preferred.

[0122] Examples of the heterocyclic ring include a pyridine ring, a triazine ring, a piperidine ring, a furan ring, a furfuran ring, a Michaelis acid ring, a barbituric acid ring, a succinimide ring, a thiophene ring, a pyrrole ring, a quinoline ring, a morpholine ring, a thiomorpholine ring, an indole ring, an imidazole ring, a pyrazole ring, a carbazole ring, a phenothiazine ring, a phenoxazine ring, an indoline ring, a pyrrolidone ring, a thiazole ring, a pyrazine ring, a thiadiazine ring, a benzoquinoline ring, and a thiadiazole ring.

[0123] The heterocyclic ring may form a salt structure. For example, a pyridine ring may form a pyridinium salt or exist as a pyridinium ion.

[0124] The aryl group and the monovalent heterocyclic group may have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, an alkenyl group, an alkynyl group, an aryl group, a monovalent heterocyclic group, a nitro group, a cyano group, -OR T 、-C(=O)R T 、-C(=O)OR T 、-OC(=O)R T 、-N(R T )2, -NHC(=O)R T 、-C(=O)N(R T )2, -NHC(=O)OR T 、-OC(=O)N(R T )2, -NHC(=O)N(R T )2. -SR T 、-S(=O)2R T 、-S(=O)2OR T 、-NHS(=O)2R T and -S(=O)2N(R T )2.

[0125] R T Each independently represents a hydrogen atom, an alkyl group, an aryl group or a monovalent heterocyclic group, and is preferably a hydrogen atom, an alkyl group or an aryl group.

[0126] As RT The alkyl group in the group is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, and further preferably a methyl group or an ethyl group.

[0127] R T The aryl group in is preferably an aryl group having 6 to 20 carbon atoms, more preferably a phenyl group or a naphthyl group, and further preferably a phenyl group.

[0128] R T The heterocyclic ring in the monovalent heterocyclic group is preferably a 5-membered ring or a 6-membered ring. Furthermore, the heterocyclic ring may form a condensed ring with an aliphatic ring, an aromatic ring or another heterocyclic ring.

[0129] Examples of the hetero atom in the heterocyclic ring include a N atom, an O atom and a S atom, and a N atom is preferred.

[0130] Examples of the heterocyclic ring include a pyridine ring, a piperidine ring, a piperazine ring, a pyrrolidine ring, a furan ring, a tetrahydrofuran ring, a tetrahydropyran ring, a thiophene ring, a pyrrole ring, a quinoline ring, a morpholine ring, an indole ring, an imidazole ring, a pyrazole ring, a carbazole ring, a phenothiazine ring, a phenoxazine ring, an indoline ring, a pyrrolidone ring, a thiazole ring, a pyrazine ring, a thiadiazine ring, a benzoquinoline ring and a thiadiazole ring.

[0131] R T The monovalent heterocyclic group in may further have a substituent. Examples of the substituent include: T The preferred aspects are also the same for the groups represented by .

[0132] Examples of the amino group include an unsubstituted amino group and a substituted amino group, and a diarylamino group or a diheteroarylamino group is preferred.

[0133] Examples of the substituent in the substituted amino group include an alkyl group, an aryl group, and a monovalent heterocyclic group. The meanings of the alkyl group, the aryl group, and the monovalent heterocyclic group in the substituted amino group are the same as those in T A The alkyl group, aryl group or monovalent heterocyclic group in are the same, and the preferred aspects are also the same.

[0134] The trialkylsilyl group is preferably a trialkylsilyl group having an alkyl group with 1 to 10 carbon atoms, and more preferably a trialkylsilyl group having an alkyl group with 1 to 4 carbon atoms. Examples of the trialkylsilyl group include trimethylsilyl, dimethylbutylsilyl, triethylsilyl, and triisopropylsilyl.

[0135] The trialkoxysilyl group is preferably a trialkoxysilyl group having an alkoxy group with 1 to 10 carbon atoms, and more preferably a trialkoxysilyl group having an alkoxy group with 1 to 4 carbon atoms. Examples of the trialkoxysilyl group include a trimethoxysilyl group and a triethoxysilyl group.

[0136] When S Arepresents a single bond or an alkylene group and T A When an alkyl group is represented, S A and T A The total number of carbon atoms contained in is preferably 3 or more, more preferably 4 or more, and further preferably 5 or more.

[0137] Furthermore, from the viewpoint of dispersibility, the total number of carbon atoms is preferably 20 or less, and more preferably 10 or less. From the viewpoint of dispersibility, in Formula A, T A Preferred is a heterocyclic group containing a nitrogen atom, an aryl group or a halogen atom.

[0138] Specific examples of the substituent represented by formula A (substituent A) include the following substituents A-1 to A-55. However, the substituent A in the present invention is not limited thereto. In the following substituents A-1 to A-55, iC 10 represents isodecyl, i-C8 represents isooctyl, and * represents the same as L in formula 1 1 bonding part.

[0139] [Chemical formula 10]

[0140]

[0141] [Chemical formula 11]

[0142]

[0143] [Chemical formula 12]

[0144]

[0145] Among the substituents A-1 to A-55, from the viewpoint that the cyanine dye is more likely to form an aggregate, substituents A-1, A-4, A-5, A-8, A-10, A-24, A-34, A-39, A-41 to 43, A-48 or A49 to A55 are preferred.

[0146] The following shows the 1 Specific examples of methine chains represented by L 1 The methine chain represented by is not limited to the following specific examples. In the following specific examples, the wavy lines each independently represent the same as L in Formula 1. 1 In addition, Me represents a methyl group, Et represents an ethyl group, and Ph represents a phenyl group.

[0147] [Chemical formula 13]

[0148]

[0149] [Chemical formula 14]

[0150]

[0151] From the viewpoint that cyanine pigments are more likely to form an association, L 1 The methine chain represented by is preferably LA1-LA8, LA11-19, LA21-24 or LA27-30.

[0152] [R 1 and R 2 ]

[0153] R 1 and R 2 Each independently represents an aliphatic group or an aromatic group. The aliphatic group and the aromatic group may have a substituent. As the substituent, a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom and an iodine atom), a cyano group, a nitro group, an aliphatic group, an aromatic group, a heterocyclic group, -OR 10 、-COR 11 、-COOR 12 、-OCOR 13 、-NR 14 R 15 、-NHCOR 16 、-CONR 17 R 18 、-NHCONR 19 R 20 、-NHCOOR 21 、-SR 22 、-SO2R 23 、-SO2OR 24 、-NHSO2R 25 and SO2NR 26 R 27 . R 10 ~R 27 Each independently represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group. Examples thereof include a hydroxyl group, a carboxyl group, a sulfo group, an alkoxy group and an amino group. Among them, the substituent is preferably an aliphatic group, an aromatic group, -OR 10 、-COOR 12 OR-SO2OR 24 , more preferably an aromatic group, -SO2OR 24 In addition, -COOR 12 R 12 When it is a hydrogen atom (i.e., a carboxyl group), the hydrogen atom may be dissociated (i.e., a carboxylate group) or in a salt state. 24 R 24 When it is a hydrogen atom (ie, a sulfo group), the hydrogen atom may be dissociated (ie, a sulfonate group) or may be in the state of a salt.

[0154] Examples of the aliphatic group include an alkyl group, an alkenyl group, an alkynyl group, and an aralkyl group, and examples of the aromatic group include an aryl group.

[0155] By R 1 and R 2 The alkyl group represented by each may be cyclic or chain-shaped. The chain-shaped alkyl group may be a straight-chain alkyl group or a branched alkyl group. The number of carbon atoms of the alkyl group (when having a substituent, the number of carbon atoms of the part excluding the substituent) is preferably 1 to 20, more preferably 1 to 12, and further preferably 1 to 8. Examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, butyl, tert-butyl, cyclopropyl, cyclohexyl, and 2-ethylhexyl. Examples of the alkyl group having a substituent include 2-hydroxyethyl, 2-carboxyethyl, 2-methoxyethyl, 2-phenoxyethyl, 2-(1-naphthyloxy)ethyl, 2-diethylaminoethyl, 2-sulfoethyl, 2-methoxypropyl, 3-methoxypropyl, 3-sulfopropyl, 3-sulfobutyl, and 4-sulfobutyl.

[0156] By R 1 and R 2 The alkenyl groups represented by each may be cyclic or chained. Chained alkenyl groups may be straight-chain alkenyl groups or branched alkenyl groups. The number of carbon atoms of the alkenyl group (when having a substituent, the number of carbon atoms of the part other than the substituent) is preferably 2 to 20, more preferably 2 to 12, and further preferably 2 to 8. Examples of the alkenyl group include vinyl, allyl, 1-propenyl, 2-butenyl, 2-pentenyl and 2-hexenyl.

[0157] By R 1 and R 2 The alkynyl groups represented by each may be cyclic or chain-shaped. Chain-shaped alkynyl groups may be straight-chain alkynyl groups or branched-chain alkynyl groups. The number of carbon atoms of the alkynyl group (when having a substituent, the number of carbon atoms of the part other than the substituent) is preferably 2 to 20, more preferably 2 to 12, and further preferably 2 to 8. Examples of the alkynyl group include ethynyl and 2-propynyl.

[0158] By R 1 and R 2 The alkyl part of each aralkyl group is the same as the above-mentioned alkyl group. The aryl part of the aralkyl group which may have a substituent is the same as the aryl group described below. Examples of the aralkyl group include benzyl and phenethyl.

[0159] By R 1 and R 2 The carbon number of each aryl group (when having a substituent, the carbon number of the portion excluding the substituent) is preferably 6 to 25, more preferably 6 to 15, and even more preferably 6 to 10. Examples of the aryl group include phenyl and naphthyl.

[0160] Examples of the aryl group having a substituent include a 4-carboxyphenyl group, a 4-acetamidophenyl group, a 3-methanesulfonamidophenyl group, a 4-methoxyphenyl group, a 3-carboxyphenyl group, a 3,5-dicarboxyphenyl group, a 4-methanesulfonamidophenyl group, and a 4-butanesulfonamidophenyl group.

[0161] [T 1 and T 2 ]

[0162] T 1 and T 2 Each independently represents a group of non-metal atoms which forms a nitrogen-containing heterocyclic ring which may be condensed into a 5-membered ring or a 6-membered ring.

[0163] Another heterocyclic ring, an aromatic ring, or an aliphatic ring may be condensed to the nitrogen-containing heterocyclic ring.

[0164] The nitrogen-containing heterocyclic ring is preferably a 5-membered ring, and more preferably a benzene ring or a naphthalene ring is fused to the 5-membered nitrogen-containing heterocyclic ring.

[0165] As the nitrogen-containing heterocyclic ring, for example, an oxazole ring, an isoxazole ring, a benzoxazole ring, a naphthooxazole ring, an oxazolocarbazole ring, an oxazolodibenzofuran ring, a thiazole ring, a benzothiazole ring, a naphthothiazole ring, an indolenine ring, a benzoindolenine ring, an imidazole ring, a benzimidazole ring, a naphthoimidazole ring, a quinoline ring, a pyridine ring, a pyrrolopyridine ring, a furanopyrrole ring, an indolizine ring, an imidazoquinoxaline ring, and a quinoxaline ring can be cited. Among them, the nitrogen-containing heterocyclic ring is preferably a quinoline ring, an indolenine ring, a benzoindolenine ring, a benzoxazole ring, a benzothiazole ring, or a benzimidazole ring, and more preferably an indolenine ring, a benzoindolenine ring, a benzothiazole ring, or a benzimidazole ring.

[0166] The nitrogen-containing heterocyclic ring and the ring condensed to the nitrogen-containing heterocyclic ring may have a substituent.

[0167] Examples of the substituent include a halogen atom, a cyano group, a nitro group, an aliphatic group, an aromatic group, a heterocyclic group, -OR 10 、-COR 11 、-COOR 12 、-OCOR 13 、-NR 14 R 15 、-NHCOR 16 、-CONR 17 R 18 、-NHCONR 19 R 20 、-NHCOOR 21 、-SR 22 、-SO2R 23 、-SO2OR 24 、-NHSO2R 25 and SO2NR 26 R 27 . R10 ~R 27 Each independently represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group. 12 R 12 When it is a hydrogen atom (i.e., a carboxyl group), the hydrogen atom may be dissociated (i.e., a carboxylate group) or in a salt state. 24 R 24 When it is a hydrogen atom (i.e., a sulfonic group), the hydrogen atom may be dissociated (i.e., a sulfonic ester group) or in a salt state. Among them, the substituent is preferably -COOR 12 OR-SO2OR 24 , more preferably -SO2OR 24 .

[0168] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0169] As R 10 ~R 27 The aliphatic group and aromatic group represented by each include 1 and R 2 The aliphatic group and the aromatic group represented by each are the same group.

[0170] The heterocyclic group may have a substituent. As the substituent, the substituents which may be possessed by the above-mentioned aliphatic group can be mentioned, and the preferred range is also the same.

[0171] The heterocyclic ring of the heterocyclic group is preferably a 5-membered ring or a 6-membered ring. The heterocyclic ring may be a monocyclic ring or a condensed ring. Examples of the heterocyclic ring include a pyridine ring, a piperidine ring, a furan ring, a furfuran ring, a thiophene ring, a pyrrole ring, a quinoline ring, a morpholine ring, an indole ring, an imidazole ring, a pyrazole ring, a carbazole ring, a phenothiazine ring, a phenoxazine ring, an indoline ring, a thiazole ring, a pyrazine ring, a thiadiazine ring, a benzoquinoline ring, and a thiadiazole ring.

[0172] Among them, the substituent is preferably -COOR 12 OR-SO2OR 24 , more preferably -SO2OR 24 .

[0173] [Cy]

[0174] Cy is an anionic part. Cy has one or more anionic groups to make the anionic part as a whole negatively charged. When the anionic group is a monovalent anionic group, Cy has two or more anionic groups. The position of the anionic group is not particularly limited. The anionic group may be included in L 1 , R 1 and R 2 It can also be included in T 1and T 2 The anionic group is preferably a sulfo group or a carboxyl group, and more preferably a sulfo group.

[0175] Cy is preferably an anion moiety represented by the following formula 3.

[0176] [Chemical formula 15]

[0177]

[0178] In formula 3, Y 1 and Y 2 Represent CR independently 3 R 4 -, -O-, -S-, -Se-, or -NR 5 -. R 3 , R 4 and R 5 R each independently represents a hydrogen atom, an aliphatic group or an aromatic ring group. 3 and R 4 They may be bonded to each other to form a ring. 1 and A 2 Each independently represents a non-metallic atom group forming an aromatic ring or an aromatic heterocyclic ring. 1 , R 1 and R 2 The meaning is the same as L in formula 1 1 , R 1 and R 2 same.

[0179] [Y 1 and Y 2 ]

[0180] Y 1 and Y 2 Represent CR independently 3 R 4 -, -O-, -S-, -Se-, or -NR 5 -.Y 1 and Y 2 Preferably, CR 3 R 4 -, -O-, -S-, more preferably CR 3 R 4 -.

[0181] As R 3 , R 4 and R 5 The aliphatic group and aromatic group represented by each include 1 and R 2 The aliphatic group and the aromatic group represented by each are the same group.

[0182] Among them, R 3 , R 4 and R 5 Each of them is independently preferably an alkyl group. The number of carbon atoms in the alkyl group is preferably 1 to 10, more preferably 1 to 5, and further preferably 1 to 3. The alkyl group may be any of a linear alkyl group, a branched alkyl group, and a cyclic alkyl group. 3 , R 4 and R 5 Each of them independently is preferably a linear alkyl group or a branched alkyl group, more preferably a linear alkyl group, further preferably a methyl group or an ethyl group, and particularly preferably a methyl group.

[0183] [A 1 and A 2 ]

[0184] A 1 and A 2 Each independently represents a non-metallic atom group forming an aromatic ring or an aromatic heterocyclic ring. The aromatic ring and the aromatic heterocyclic ring may have a substituent.

[0185] As A 1 and A 2 The substituents that the aromatic ring and the aromatic heterocyclic ring formed by each other may have include T in Formula 1. 1 and T 2 The substituents that the nitrogen-containing heterocyclic ring formed and the ring condensed therewith may have are the same as those.

[0186] Among them, the substituent is preferably -COOR 12 OR-SO2OR 24 , more preferably -SO2OR 24 .

[0187] As A 1 and A 2 Examples of the aromatic rings formed by each include a benzene ring and a naphthalene ring.

[0188] By A 1 and A 2 The aromatic heterocyclic ring formed by each ring is preferably an aromatic heterocyclic ring in which at least one of the atoms forming the ring is a nitrogen atom, an oxygen atom or a sulfur atom. 1 and A 2 The aromatic heterocyclic ring formed individually may be condensed with another ring (aliphatic ring, aromatic ring or heterocyclic ring).

[0189] By A 1 and A 2 The aromatic heterocyclic rings each formed are preferably 5- to 10-membered rings.

[0190] As A 1 and A 2Examples of the aromatic heterocyclic ring formed by each of them include a pyridine ring, a dibenzofuran ring, and a carbazole ring.

[0191] From the perspective that cyanine pigments are more likely to form an association, A 1 and A 2 Each of the non-metal atoms independently forms preferably a group of non-metal atoms that forms an aromatic ring, and more preferably a group of non-metal atoms that forms a benzene ring or a naphthalene ring.

[0192] The anion part represented by Formula 3 is preferably an anion part represented by the following Formula 3A or Formula 3B.

[0193] [Chemical formula 16]

[0194]

[0195] [Chemical formula 17]

[0196]

[0197] In Formula 3A, R 1 , R 2 , Y 1 and Y 2 The meaning is the same as R in Formula 3 1 , R 2 , Y 1 and Y 2 same.

[0198] V 1A and V 2A Each independently represents a hydrogen atom or a substituent.

[0199] As V 1A and V 2A The substituents represented by each include halogen atoms, cyano groups, nitro groups, aliphatic groups, aromatic groups, heterocyclic groups, -OR 10 、-COR 11 、-COOR 12 、-OCOR 13 、-NR 14 R 15 、-NHCOR 16 、-CONR 17 R 18 、-NHCONR 19 R 20 、-NHCOOR 21 、-SR 22 、-SO2R 23 、-SO2OR 24 、-NHSO2R 25 and SO2NR 26 R 27 . R10 ~R 27 Each independently represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group. 12 R 12 When it is a hydrogen atom (i.e., a carboxyl group), the hydrogen atom may be dissociated (i.e., a carboxylate group) or in a salt state. 24 R 24 When it is a hydrogen atom (ie, a sulfo group), the hydrogen atom may be dissociated (ie, a sulfonate group) or may be in the state of a salt.

[0200] Among them, V 1A and V 2A The substituents represented by each are preferably -COOR 12 OR-SO2OR 24 , more preferably -SO2OR 24 .

[0201] V 1A and V 2A They may be the same or different from each other, but are preferably the same from the viewpoint of ease of production.

[0202] When V 1A When V is a substituent, relative to the benzene ring 1A The bonding position of R is not particularly limited, but is preferably 500 mm away from the bonding to R from the viewpoint that the cyanine pigment is more likely to form an association. 1 Similarly, when V 2A When V is a substituent, relative to the benzene ring 2A The bonding position of R is not particularly limited, but is preferably 500 mm away from the bonding to R from the viewpoint that the cyanine pigment is more likely to form an association. 2 The nitrogen atom is farthest away.

[0203] In Formula 3B, R 1 , R 2 , Y 1 and Y 2 The meaning is the same as R in Formula 3 1 , R 2 , Y 1 and Y 2 Same. 1B and V 2B Each independently represents a hydrogen atom or a substituent.

[0204] As V 1B and V 2B The substituents represented by each include those represented by V 1A and V 2A Each represents the same substituent group.

[0205] Among them, V 1B and V 2B The substituents represented by each are preferably -COOR 12 OR-SO2OR 24 , more preferably -SO2OR 24 .

[0206] V 1B and V 2B The two may be the same or different from each other, but are preferably the same from the viewpoint of ease of production.

[0207] When V 1B When V is a substituent, relative to the naphthalene ring 1B The bonding position of is not particularly limited, but is preferably 500 mm from the bonding position to R from the viewpoint that the cyanine pigment is more likely to form an association. 1 Similarly, when V 2B When V is a substituent, relative to the naphthalene ring 2B The bonding position of is not particularly limited, but is preferably 500 mm from the bonding position to R from the viewpoint that the cyanine pigment is more likely to form an association. 2 The nitrogen atom is farthest away.

[0208] From the viewpoint that the cyanine dye is more likely to form an association, Cy is more preferably an anion moiety represented by the following formula 4.

[0209] [Chemical formula 18]

[0210]

[0211] In formula 4, Y 1 and Y 2 Represent CR independently 3 R 4 -, -O-, -S-, -Se-, or -NR 5 -. R 3 , R 4 and R 5 R each independently represents a hydrogen atom, an aliphatic group or an aromatic ring group. 3 and R 4 They may be bonded to each other to form a ring. 1 and A 2 Each independently represents a non-metallic atom group forming an aromatic ring or an aromatic heterocyclic ring. 2 Each independently represents a methine chain consisting of 1, 2 or 3 methine groups, L 2 It has no substituent. 6 and R 7 R each independently represents a hydrogen atom or an aliphatic group. 6 and R 7Can be linked to each other to form a ring. 8 It is represented by the following formula A.

[0212] -S A -T A Formula A

[0213] In formula A, S A represents a single bond, alkylene, alkenylene, alkynylene, -O-, -S-, -NR L1 -, -C(=O)-, -C(=O)O-, -C(=O)NR L1 -、-S(=O)2-、-OR L2 - or a group consisting of at least two of these, R L1 Each independently represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group or a monovalent heterocyclic group, and R L2 represents an alkylene group, an arylene group or a divalent heterocyclic group, T A represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, a monovalent heterocyclic group, a cyano group, a hydroxyl group, a formyl group, a carboxyl group, an amino group, a thiol group, a sulfone group, a phosphoryl group, a boryl group, a vinyl group, an ethynyl group, a trialkylsilyl group or a trialkoxysilyl group.

[0214] In formula 4, R 1 , R 2 , R 3 , R 4 , R 5 , Y 1 and Y 2 The meaning is the same as R in Formula 3 1 , R 2 , R 3 , R 4 , R 5 , Y 1 and Y 2 same.

[0215] L 2 Each independently represents a methine chain consisting of 1, 2 or 3 methine groups. 2 Preferably, each independently represents a methine chain consisting of one or two methine groups.

[0216] 2 L 2 They may be the same or different from each other, but are preferably the same from the viewpoint of ease of production.

[0217] R 6 and R 7 R each independently represents a hydrogen atom or an aliphatic group. 6 and R 7 R is a hydrogen atom or an aliphatic group, and they are preferably linked to each other to form a ring. 6 and R7 The ring formed by connecting to each other is preferably a 5-membered aliphatic ring or a 6-membered aliphatic ring. 6 and R 7 Connected to each other -R 6 R 7 -, for example, -CH2CH2- and -CH2C(Z)2-CH2-. Z is preferably a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, more preferably a hydrogen atom or a methyl group. Two Zs may be bonded to form a ring structure.

[0218] R 8 represents a substituent represented by formula A. Preferred embodiments of the substituent represented by formula A are as described above.

[0219] In the following formula 1, it is shown that 1 Specific examples of basic core 1 and basic core 2 bonded to a methyl chain are represented. For convenience, in formula 1, basic core 1 is recorded as a cationic structure in which the nitrogen atom is cationic, and basic core 2 is recorded as a neutral structure in which the nitrogen atom is uncharged. Since there is a conjugated carbon chain between the nitrogen atom contained in basic core 1 and the nitrogen atom contained in basic core 2, it is considered that the electrons are actually in a delocalized state. Therefore, in formula 1, basic core 1 can also be recorded as a neutral structure and basic core 2 as a cationic structure. In the following specific examples, they are all recorded as cationic structures, but in the pigment compound represented by formula 1, when one basic core is a cationic structure, the other basic core is recorded as a neutral structure. In addition, basic core 1 and basic core 2 are not limited to the following specific examples. In the following specific examples, the wavy lines independently represent the L in formula 1. 1 bonding position.

[0220] [Chemical formula 19]

[0221]

[0222] [Chemical formula 20]

[0223]

[0224] [Chemical formula 21]

[0225]

[0226] In Cy, from the viewpoint of manufacturing ease, basic core 1 and basic core 2 can have the same structure. In addition, basic core 1 and basic core 2 having the same structure means that the constituent atoms are the same and the skeleton is the same. As mentioned above, when basic core 1 and basic core 2 have the same structure, as a structural formula, one of them is recorded as a cationic structure and the other is recorded as a neutral structure.

[0227] From the viewpoint that the cyanine dye can more easily form an aggregate, the basic core 1 and the basic core 2 are preferably TA1 to TA13, TA16, TA28, TA29, or TA31 to TA36.

[0228] [X 1 ]

[0229] X 1 It represents an organic cation represented by the following Formula 2-1, Formula 2-2 or Formula 2-3 or an organic cation having a structure represented by Formula 2-4.

[0230] <Formula 2-1>

[0231] [Chemical formula 22]

[0232]

[0233] In formula 2-1, A 11 and A 12 Each independently represents a nitrogen atom or a phosphorus atom, and B 11 Each independently represents a divalent linking group, R 1a , R 1b , R 1c , R 1d 、E 11 and E 12 Each independently represents an aliphatic group or an aromatic group, R 1a , R 1b , R 1c and R 1d may be bonded to each other to form a ring, m1 is an integer greater than 1,

[0234] A 11 and A 12 A and B each independently represent a nitrogen atom or a phosphorus atom. 11 and A 12 Preferred is a nitrogen atom.

[0235] A 11 and A 12 The two may be the same or different from each other, but are preferably the same from the viewpoint of ease of production.

[0236] B 11 Each independently represents a divalent linking group, and B 11 The divalent linking group represented by is preferably a group having 2 or more carbon atoms, more preferably a group having 2 to 8 carbon atoms. It is inferred that if the number of carbon atoms is 2 or more, the molecular structure becomes more flexible, so the effect of linking cyanine pigments to each other at a position where an association can be appropriately formed is high. As a result, cyanine pigments are easy to form an association, and tend to maintain infrared absorption ability for a long time.

[0237] As B11 The divalent linking group represented by R includes, for example, an alkylene group having 1 to 30 carbon atoms, an arylene group having 6 to 30 carbon atoms, a heterocyclic linking group, -CH=CH-, -O-, -S-, -C(=O)-, -COO-, -NR-, -CONR-, -OCO-, -SO-, -SO2-, and a linking group formed by linking two or more of these. R represents a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group.

[0238] Among them, by B 11 The divalent linking group represented by is preferably an alkylene group. The number of carbon atoms in the alkylene group is preferably 2 to 20, more preferably 2 to 15. The alkylene group is preferably a linear alkylene group.

[0239] R 1a , R 1b , R 1c , R 1d 、E 11 and E 12 Each independently represents an aliphatic group or an aromatic group,

[0240] Examples of the aliphatic group include an alkyl group, an alkenyl group, an alkynyl group, and an aralkyl group, and examples of the aromatic group include an aryl group.

[0241] Among them, R 1a , R 1b , R 1c and R 1d The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms.

[0242] And, E 11 and E 12 Each of them is independently preferably an alkyl group or an aryl group. The number of carbon atoms in the alkyl group is preferably 1 to 10, more preferably 1 to 6. The aryl group is preferably a phenyl group.

[0243] m1 is an integer greater than or equal to 1, and m1 is preferably 1 to 3, and more preferably 1 or 2.

[0244] Among them, the organic cation represented by formula 2-1 is more preferably A 11 and A 12 is a nitrogen atom, B 11 is an alkylene group, R 1a , R 1b , R 1c and R 1d is an alkyl group, E 11 and E 12 An organic cation which is an alkyl group.

[0245] Specific examples of the organic cation represented by Formula 2-1 are shown below, but the organic cation represented by Formula 2-1 is not limited to the following specific examples. In addition, Me represents a methyl group, Et represents an ethyl group, and Ph represents a phenyl group.

[0246] [Chemical formula 23]

[0247]

[0248] <Formula 2-2>

[0249] [Chemical formula 24]

[0250]

[0251] In formula 2-2, A 21 , A 22 and A 23 Each independently represents a nitrogen atom or a phosphorus atom, and B 21 and B 22 Each independently represents a divalent linking group, R 2a and R 2b Each independently represents an aliphatic group or an aromatic group, m2 is an integer greater than 0, G 21 Indicates that the ring contains A 21 The non-metallic atom group of the aromatic ring, G 22 Indicates that the ring contains A 23 The aromatic ring of the non-metallic atom group,

[0252] A 21 , A 22 and A 23 A and B each independently represent a nitrogen atom or a phosphorus atom. 21 , A 22 and A 23 Preferred is a nitrogen atom.

[0253] A 21 , A 22 and A 23 They may be the same or different from each other, but are preferably the same from the viewpoint of ease of production.

[0254] B 21 and B 22 Each independently represents a divalent linking group, and B 21 and B 22 The divalent linking group represented by is preferably a group having 2 or more carbon atoms, more preferably a group having 2 to 8 carbon atoms. It is inferred that if the number of carbon atoms is 2 or more, the molecular structure becomes more flexible, so the effect of linking cyanine pigments to each other at a position where an association can be appropriately formed is high. As a result, cyanine pigments are easy to form an association, and tend to maintain infrared absorption ability for a long time.

[0255] As B 21 and B 22 The divalent linking group represented by R includes, for example, an alkylene group having 1 to 30 carbon atoms, an arylene group having 6 to 30 carbon atoms, a heterocyclic linking group, -CH=CH-, -O-, -S-, -C(=O)-, -COO-, -NR-, -CONR-, -OCO-, -SO-, -SO2-, and a linking group formed by linking two or more of these. R represents a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group.

[0256] Among them, by B 21 and B 22 The divalent linking groups represented by are each independently preferably an alkylene group. The number of carbon atoms in the alkylene group is preferably 2 to 20, more preferably 2 to 15. The alkylene group is preferably a linear alkylene group.

[0257] R 2a and R 2b Each independently represents an aliphatic group or an aromatic group,

[0258] As R 2a and R 2b Examples of the aliphatic group represented by include alkyl, alkenyl, alkynyl and aralkyl groups. Examples of the aromatic group include aryl groups.

[0259] Among them, R 2a and R 2b Each of them is independently preferably an alkyl group. The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms.

[0260] m2 is an integer greater than or equal to 0, and m2 is preferably an integer from 0 to 2.

[0261] G 21 Indicates that the ring contains A 21 The non-metallic atom group of the aromatic ring, G 22 Indicates that the ring contains A 23 A non-metallic atom group of aromatic rings containing A 21 The aromatic ring of is preferably a pyridine ring, an imidazole ring, an oxazole ring or a thiazole ring. 21 The aromatic ring of may be fused with other rings (aliphatic rings, aromatic rings or heterocyclic rings). 23 The aromatic ring of is preferably a pyridine ring, an imidazole ring, an oxazole ring or a thiazole ring. 23 The aromatic ring may be condensed with other rings (aliphatic rings, aromatic rings or heterocyclic rings).

[0262] Among them, the organic cation represented by formula 2-2 is more preferably A 21 , A22 and A 23 is a nitrogen atom, B 21 and B 22 are independently alkylene, m2 is 0 or 1, G 21 and G 22 It is a pyridine ring, an imidazole ring, an oxazole ring or a thiazole ring.

[0263] Specific examples of the organic cation represented by Formula 2-2 are shown below, but the organic cation represented by Formula 2-2 is not limited to the following specific examples. In addition, Me represents a methyl group.

[0264] [Chemical formula 25]

[0265]

[0266] <Formula 2-3>

[0267] [Chemical formula 26]

[0268]

[0269] In formula 2-3, A 31 and A 32 Each independently represents a nitrogen atom or a phosphorus atom, and B 31 represents a divalent linking group, R 3a and R 3b Each independently represents an aliphatic group or an aromatic group, G 31 Indicates that the ring contains A 31 The non-metallic atom group of the aromatic ring, G 32 Indicates that the ring contains A 32 The aromatic ring of the non-metallic atom group,

[0270] A 31 and A 32 A and B each independently represent a nitrogen atom or a phosphorus atom. 31 and A 32 Preferred is a nitrogen atom.

[0271] A 31 and A 32 The two may be the same or different from each other, but are preferably the same from the viewpoint of ease of production.

[0272] B 31 Represents a divalent linking group, consisting of B 31 The number of carbon atoms of the divalent linking group represented by is preferably 2 or more, more preferably 2 to 8. When the number of carbon atoms is 2 or more, the association formed by the cyanine dyes is held in an appropriate position, and the infrared absorption ability tends to be maintained for a long time.

[0273] As B31 The divalent linking group represented by R includes, for example, an alkylene group having 1 to 30 carbon atoms, an arylene group having 6 to 30 carbon atoms, a heterocyclic linking group, -CH=CH-, -O-, -S-, -C(=O)-, -COO-, -NR-, -CONR-, -OCO-, -SO-, -SO2-, and a linking group formed by linking two or more of these. R represents a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group.

[0274] Among them, by B 31 The divalent linking group represented by is preferably an alkylene group. The number of carbon atoms in the alkylene group is preferably 2 to 20, more preferably 2 to 15. The alkylene group is preferably a linear alkylene group.

[0275] R 3a and R 3b Each independently represents an aliphatic group or an aromatic group,

[0276] Examples of the aliphatic group include an alkyl group, an alkenyl group, an alkynyl group, and an aralkyl group, and examples of the aromatic group include an aryl group.

[0277] Among them, R 3a and R 3b Each of them is independently preferably an alkyl group. The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms.

[0278] G 31 Indicates that the ring contains A 31 The non-metallic atom group of the aromatic ring, G 32 Indicates that the ring contains A 32 A non-metallic atom group of aromatic rings containing A 31 The aromatic ring of is preferably a pyridine ring. 31 The aromatic ring of may be fused with other rings (aliphatic rings, aromatic rings or heterocyclic rings). 32 The aromatic ring of is preferably a pyridine ring. 32 The aromatic ring may be condensed with other rings (aliphatic rings, aromatic rings or heterocyclic rings).

[0279] The organic cation represented by Formula 2-3 is more preferably A 31 and A 32 is a nitrogen atom, B 31 is an alkylene group, R 3a and R 3b are independently alkyl, G 31 and G 32 It is an organic cation of the pyridine ring.

[0280] Specific examples of the organic cation represented by Formula 2-3 are shown below, but the organic cation represented by Formula 2-3 is not limited to the following specific examples.

[0281] [Chemical formula 27]

[0282]

[0283] <Formula 2-4>

[0284] [Chemical formula 28]

[0285]

[0286] In formula 2-4, A 41 Each independently represents a nitrogen atom or a phosphorus atom. 41 Each independently represents a single bond or a divalent linking group, R 4a , R 4b and R 4c Each independently represents an aliphatic group or an aromatic group, and E 41 and E 42 Each independently represents a single bond or an aliphatic group, R 4a , R 4b and R 4c One of them can be combined with E 41 or E 42 They are bonded to form a ring, and m4 is an integer greater than or equal to 2.

[0287] The organic cation having the structure represented by Formula 2-4 has a flexible molecular structure and the cationic sites are regularly arranged, so it is considered that the cyanine pigment is regularly arranged at appropriate positions to form an association. As a result, the infrared absorption ability tends to be maintained for a long time.

[0288] A 41 A and B each independently represent a nitrogen atom or a phosphorus atom. 41 Preferred is a nitrogen atom.

[0289] B 41 Each independently represents a single bond or a divalent linking group, as B 41 The divalent linking group represented by R includes, for example, an alkylene group having 1 to 30 carbon atoms, an arylene group having 6 to 30 carbon atoms, a heterocyclic linking group, -CH=CH-, -O-, -S-, -C(=O)-, -COO-, -NR-, -CONR-, -OCO-, -SO-, -SO2-, and a linking group formed by linking two or more of these. R represents a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group.

[0290] Among them, B 41The divalent linking group represented by is preferably an alkylene group. The number of carbon atoms in the alkylene group is preferably 1 to 6, more preferably 1 to 4. The alkylene group is preferably a linear alkylene group.

[0291] R 4a , R 4b and R 4c Each independently represents an aliphatic group or an aromatic group,

[0292] Examples of the aliphatic group include an alkyl group, an alkenyl group, an alkynyl group, and an aralkyl group, and examples of the aromatic group include an aryl group.

[0293] Among them, R 4a , R 4b and R 4c The alkyl group preferably has 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms.

[0294] E 41 and E 42 Each independently represents a single bond or an aliphatic group,

[0295] And, E 11 and E 12 Each of them is independently preferably a single bond or an alkyl group. The number of carbon atoms in the alkyl group is preferably 1 to 6, more preferably 1 to 4. The aryl group is preferably a phenyl group.

[0296] m4 is an integer greater than or equal to 2. m4 is preferably 50 to 3,000, more preferably 100 to 2,000.

[0297] Among them, the organic cation having a structure represented by Formula 2-4 is more preferably A 41 is a nitrogen atom, R 4a , R 4b and R 4c 1 of them with E 41 or E 42 An organic cation that is bonded to form a ring.

[0298] Specific examples of organic cations having a structure represented by Formula 2-4 are shown below, but X 1 The organic cation represented by is not limited to the following specific examples. In addition, Me represents a methyl group, and m4 has the same meaning as m4 in Formula 2-4.

[0299] [Chemical formula 29]

[0300]

[0301] X 1Preferably, it is an organic cation represented by Formula 2-1 or an organic cation having a structure represented by Formula 2-4. It is believed that the association formed by the cyanine pigment is held in a suitable position for a long time by the organic cation represented by Formula 2-1 or the organic cation having a structure represented by Formula 2-4. 1 When the organic cation is represented by Formula 2-1 or an organic cation having a structure represented by Formula 2-4, the invisibility is excellent and the infrared absorption capability can be maintained for a longer period of time.

[0302] [n]

[0303] n is a non-zero number required for neutralizing charges. For example, when the anion portion is a monovalent anion and the organic cation is a divalent cation, n is 0.5.

[0304] Specific examples of the pigment compound represented by Formula 1 are shown below. However, the pigment compound represented by Formula 1 in the present invention is not limited to the following specific examples.

[0305] [Chemical formula 30]

[0306]

[0307] [Chemical formula 31]

[0308]

[0309] The content of the pigment compound represented by Formula 1 is preferably 0.3% by mass to 3% by mass, and more preferably 0.5% by mass to 1.0% by mass, relative to the total amount of the ink.

[0310] <Dispersant>

[0311] The ink of the present invention comprises at least one dispersant. The dispersant is a polymer comprising an acidic functional group and an ethylene oxide chain.

[0312] The dispersant may be a low molecular weight compound having a molecular weight of less than 1000, or a high molecular weight compound (i.e., a polymer) having a molecular weight of more than 1000. In the case of a low molecular weight compound, the molecular weight can be calculated based on the type and number of atoms constituting the compound. In the case of a high molecular weight compound, as described later, the molecular weight is represented by the weight average molecular weight.

[0313] From the viewpoint of enhancing the hydrophobic interaction with the pigment compound represented by Formula 1, the dispersant is preferably a polymer.

[0314] If the dispersant contains an acidic functional group, it is easy to transfer from a state where the pigment compound represented by Formula 1 is slightly dissolved in the dispersion medium (water and a water-soluble organic solvent) to a state where the pigment compound represented by Formula 1 forms an association. In addition, it is believed that if the dispersant contains an ethylene oxide chain, the hydrophobic interaction between the ethylene oxide chain and the pigment compound represented by Formula 1 stabilizes the formed association.

[0315] Examples of the acidic functional group contained in the dispersant include a carboxyl group, a sulfone group, a phosphonic acid group, a phosphoric acid group, and a sulfonamide group.

[0316] In the present invention, the acidic functional group is a concept including both an unneutralized acidic functional group (eg, a carboxyl group) and a neutralized acidic functional group (eg, a salt of a carboxyl group (eg, -C(=O)ONa)).

[0317] The acidic functional group to be neutralized is preferably a -C(=O)OM group (wherein M represents an alkali metal, an ammonium ion or an organic cation).

[0318] Examples of the organic cation include alkylammonium cations having 1 to 10 carbon atoms, hydroxy-substituted alkylammonium cations having 1 to 10 carbon atoms, carboxyl-substituted alkylammonium cations having 2 to 10 carbon atoms, and organic cations having 2 to 10 alkyleneimine units having 2 to 4 carbon atoms.

[0319] The unneutralized acidic functional group is preferably a carboxyl group (—C(═O)OH group).

[0320] Neutralization of the acidic functional group can be performed by reacting an unneutralized dispersant with a base (hereinafter also referred to as a “neutralizing base”).

[0321] Examples of the neutralizing base include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; ammonia; and organic amines such as dimethylethanolamine and diisopropylethylamine.

[0322] The number of repetitions of the ethylene oxide chain contained in the dispersant is preferably 3 or more, more preferably 5 or more, from the viewpoint of enhancing the hydrophobic interaction with the pigment compound represented by Formula 1. The upper limit of the number of repetitions is 50, for example.

[0323] Among them, the dispersant is preferably a polymer containing a structural unit derived from at least one selected from the group consisting of styrene and styrene derivatives, and more preferably a polymer containing a structural unit derived from styrene.

[0324] The π-π interaction between the structural unit derived from at least one selected from the group consisting of styrene and styrene derivatives and the pigment compound represented by Formula 1 further stabilizes the association.

[0325] Examples of styrene derivatives include alkyl-substituted styrenes such as α-methylstyrene, 4-methylstyrene, 2-methylstyrene, 3-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, and 4-ethylstyrene; halogen-substituted styrenes such as 2-chlorostyrene, 3-chlorostyrene, and 4-chlorostyrene; fluorine-substituted styrenes such as 4-fluorostyrene and 2,5-difluorostyrene; and vinylnaphthalene.

[0326] From the viewpoint of further stabilizing the association, the content of the structural unit derived from at least one selected from the group consisting of styrene and styrene derivatives is preferably 1 mol % to 60 mol %, more preferably 1 mol % to 50 mol % based on the total amount of the dispersant.

[0327] If the structural unit derived from at least one selected from the group consisting of styrene and styrene derivatives is 60 mol% or less, the aggregation between the pigments is suppressed and the associated compound is stabilized. On the other hand, if the structural unit is 1 mol% or more, the associated compound is further stabilized by the π-π interaction with the pigment compound represented by Formula 1.

[0328] From the viewpoint of easy formation of an association, the acid value of the dispersant is preferably 20 mgKOH / g or more, more preferably 30 mgKOH / g or more. From the viewpoint of dispersion stability, the upper limit of the acid value of the dispersant is preferably 100 mgKOH / g or more.

[0329] The dispersant may be a commercially available product.

[0330] As a commercially available product, SOLSPERSE41000, DISPERBYK-190, DISPERBYK-191, DISPERBYK-180, DISPERBYK-187, DISPERBYK-194, SOLSPERSE54000, and SOLSPERSE55000 are mentioned, for example.

[0331] When the dispersant is a polymer, the weight average molecular weight is preferably 3,000 to 200,000, more preferably 5,000 to 100,000.

[0332] In the present invention, the weight average molecular weight (Mw) is measured by gel permeation chromatography (GPC). HLC-8220GPC (manufactured by Tosoh Corporation) is used in GPC. As a column, three TSKgeL SuperHZM-H, TSKgeLSuperHZ4000, and TSKgel SuperHZ2000 (all trade names manufactured by Tosoh Corporation) are connected in series, and THF (tetrahydrofuran) is used as an eluent. And, as a condition, the sample concentration is set to 0.45% by mass, the flow rate is set to 0.35ml / min, the sample injection amount is set to 10μL, the measurement temperature is set to 40°C, and a differential refractive index detector is used. And, the calibration curve is made according to the eight samples of "Standard Sample TSK standard, polystyrene (polystyrene)" manufactured by Tosoh Corporation: "F-40", "F-20", "F-4", "F-1", "A-5000", "A-2500", "A-1000", and "n-propylbenzene".

[0333] In the ink of the present invention, the mass ratio of the content of the dispersant to the content of the pigment compound represented by Formula 1 (dispersant / pigment compound) is preferably 0.1 to 3, more preferably 0.2 to 2, and further preferably 0.3 to 1.5.

[0334] <Water-soluble organic solvent, water>

[0335] The ink of the present invention contains at least one water-soluble organic solvent and water.

[0336] In the present invention, "water-soluble" means a property that 1 g or more of a compound dissolves in 100 g of water at 25°C.

[0337] Specific examples of the water-soluble organic solvent are as follows.

[0338] Alcohols (e.g., methanol, ethanol, propanol, isopropanol, butanol, isobutanol, sec-butanol, tert-butanol, pentanol, hexanol, cyclohexanol, benzyl alcohol, etc.),

[0339] Polyols (e.g., ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, hexylene glycol, pentylene glycol, glycerol, hexanetriol, thiodiglycol, 2-methylpropanediol, etc.).

[0340] Polyol ethers (for example, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, tripropylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monomethyl ether acetate, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, ethylene glycol monophenyl ether, propylene glycol monophenyl ether, etc.).

[0341] From the viewpoint of suppressing drying of the ink, the boiling point of the water-soluble organic solvent is preferably 100° C. or higher. The boiling point is a value under atmospheric pressure (101.325 kPa).

[0342] From the viewpoint of containing less impurities, water is preferably distilled water, ion-exchanged water, ion-exchanged distilled water or pure water.

[0343] The SP value of the mixed solvent composed of water and a water-soluble organic solvent is preferably 40.0 MPa. 1 / 2 More preferably 41.5 MPa 1 / 2 The upper limit of the SP value of the mixed solvent is not particularly limited, and is, for example, 47.0 MPa. 1 / 2 .

[0344] In the ink of the present invention, water and a water-soluble organic solvent are present as a dispersion medium.

[0345] If the SP value of the mixed solvent is 40.0 MPa 1 / 2 As described above, it is easy to shift from a state where the pigment compound represented by Formula 1 is slightly dissolved in the dispersion medium (water and a water-soluble organic solvent) to a state where the pigment compound represented by Formula 1 forms an association.

[0346] The SP value of the mixed solvent composed of water and a water-soluble organic solvent contained in the ink is calculated by the following method by determining the type of the water-soluble organic solvent contained in the ink and the contents of water and the water-soluble organic solvent.

[0347] In the present invention, the SP value represents the Hansen solubility parameter. The Hansen solubility parameter is a solubility parameter introduced by Hildebrand divided into three components, namely, a dispersion term δd, a polar term δp, and a hydrogen bonding term δh, and expressed in a three-dimensional space.

[0348] The SP value δ is a value calculated using the following formula E.

[0349] SP value δ[MPa 1 / 2 ]=(δd 2 ++δp 2 +δh 2 ) 1 / 2 ……(E)

[0350] In addition, the dispersion term δd, polar term δp and hydrogen bond term δh were calculated using HSPiP (version 4.1.07) software.

[0351] The SP value of the mixed solvent is calculated using the following method. First, the weighted average values ​​of the dispersion term, polar term, and hydrogen bond term of the mixed solvent contained in the ink are calculated as δd, δp, and δh. Then, the SP value is calculated using the above formula E based on the calculated δd, δp, and δh.

[0352] δd is calculated using the following formula B1: In formula B1, δdm represents the dispersion term of the mth (m represents an integer greater than or equal to 1) component in the mixed solvent, and Wm represents the content ratio (mass %) of the mth component relative to the total amount of the ink.

[0353] δd=ΣδdmWm / ΣWm……(B1)

[0354] Similarly, δp and δh are calculated by the following formula B2 and formula B3.

[0355] δp=ΣδpmWm / ΣWm……(B2)

[0356] δh=ΣδhmWm / ΣWm……(B3)

[0357] In Formula B2, δpm represents the polarity term of the m-th (m represents an integer greater than or equal to 1) component in the mixed solvent.

[0358] In Formula B3, δhm represents the hydrogen bonding term of the m-th (m represents an integer greater than or equal to 1) component in the mixed solvent.

[0359] In addition, the components of the mixed solvent are water and a water-soluble organic solvent. When there are two types of water-soluble organic solvents, the components of the mixed solvent become three types (water and two types of water-soluble organic solvents).

[0360] When the SP value of the water-soluble organic solvent is set to A[MPa 1 / 2 ], when the ratio of the water-soluble organic solvent to the total content of water and the water-soluble organic solvent is set to B mass %, A and B preferably satisfy the following formula T1.

[0361] 10≤B≤1.6×A-7…(T1).

[0362] In Formula T1, when B is 10 or more, the complex is further stabilized and the infrared absorption ability is maintained for a longer period of time than before.

[0363] In Formula T1, when B is "1.6×A-7" or less, the invisibility is excellent.

[0364] From the viewpoint of maintaining the infrared absorption capability for a longer period of time, A and B more preferably satisfy the following formula T2.

[0365] 10≤B≤1.6×A-12……(T2)

[0366] The SP value of the water-soluble organic solvent (i.e., the above-mentioned A) is preferably 17 MPa. 1 / 2 ~40MPa 1 / 2 , more preferably 20MPa 1 / 2 ~40MPa 1 / 2 .

[0367] Specific examples of the SP value of the water-soluble organic solvent are as follows.

[0368] Ethylene glycol monohexyl ether: 20.3MPa 1 / 2

[0369] ·Diethylene glycol monoethyl ether: 22.2MPa 1 / 2

[0370] 1,3-Butanediol: 27.8MPa 1 / 2

[0371] Propylene glycol: 29.1MPa 1 / 2

[0372] Ethylene glycol monobutyl ether: 20.8MPa 1 / 2

[0373] Ethylene glycol monopropyl ether: 22.7MPa 1 / 2

[0374] Tripropylene glycol monomethyl ether: 19.3MPa 1 / 2

[0375] ·Dipropylene glycol methyl ether: 20.0MPa 1 / 2

[0376] Propylene glycol monomethyl ether: 20.4MPa 1 / 2

[0377] Propylene glycol monopropyl ether: 19.6MPa 1 / 2

[0378] Propylene glycol monobutyl ether: 18.4MPa 1 / 2

[0379] ·Diethylene glycol monobutyl ether: 20.4MPa 1 / 2

[0380] Diethylene glycol diethyl ether: 17.8MPa 1 / 2

[0381] When there are two or more water-soluble organic solvents, the SP value of the water-soluble organic solvent is calculated by the same method as the SP value of the above-mentioned mixed solvent.

[0382] The ratio of the content of the water-soluble organic solvent to the total content of water and the water-soluble organic solvent (ie, the above-mentioned B) is preferably 15% by mass to 35% by mass, and more preferably 17% by mass to 30% by mass.

[0383] When the content of B is 15% by mass or more, the ejection property is good. On the other hand, when the content of B is 35% by mass or less, the association is further stabilized and the infrared absorption ability is maintained for a longer period of time than before.

[0384] The water content is preferably 30% by mass or more, more preferably 40% by mass or more, and even more preferably 50% by mass or more relative to the total amount of the ink. The upper limit of the water content is, for example, 85% by mass.

[0385] The ink of the present invention may contain a surfactant, but preferably contains no surfactant from the viewpoint of ensuring the hydrophobic interaction between the dispersant and the pigment compound represented by Formula 1.

[0386] The content of the surfactant is preferably 1% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.1% by mass or less, based on the total amount of the ink.

[0387] The ink of the present invention may contain known additives used in inks.

[0388] Examples of additives include surfactants, resins, anti-desiccant (in other words, wetting agents), anti-fading agents, emulsion stabilizers, penetration enhancers, preservatives, antifungal agents, pH adjusters, surface tension adjusters, defoamers, viscosity adjusters, rust inhibitors, and chelating agents.

[0389] The ink of the present invention may contain other pigments in addition to the pigment compound represented by Formula 1. The other pigments are not particularly limited, and pigments known in the field of inks can be used.

[0390] From the viewpoint of invisibility, the content of other coloring matter is preferably 0.1% by mass or less, and more preferably 0.05% by mass or less, relative to the total mass of the ink.

[0391] (physical properties)

[0392] From the viewpoint of ejection stability, the pH of the ink is preferably 7 to 10, more preferably 7.5 to 9.5. The pH of the ink is measured at 25° C. using a pH meter, for example, a pH meter manufactured by DKK-TOA Corporation (model “HM-31”).

[0393] The viscosity of the ink is preferably 0.5 mPa·s to 30 mPa·s, more preferably 2 mPa·s to 20 mPa·s, further preferably 2 mPa·s to 15 mPa·s, and further preferably 3 mPa·s to 10 mPa·s. The viscosity of the ink is measured at 25° C. using a viscometer, for example, a TV-22 viscometer manufactured by Toki Sangyo Co., Ltd.

[0394] The surface tension of the ink is preferably 60 mN / m or less, more preferably 20 mN / m to 50 mN / m, and further preferably 25 mN / m to 45 mN / m. The surface tension of the ink is measured at 25° C. using a surface tensiometer, for example, using an automatic surface tensiometer manufactured by Kyowa Interface Science Co., LTD. (product name “CBVP-Z”), and measured by a plate method.

[0395] <<Inkjet recording method>>

[0396] The inkjet recording method of the present invention includes the step of applying the above-mentioned ink to a substrate by an inkjet recording method.

[0397] The substrate is not particularly limited as long as an image can be formed, and examples thereof include paper, cloth, wood, metal plates, and resin films. The substrate may be subjected to a surface treatment in advance.

[0398] Examples of the paper include pure white roll paper, kraft paper, cardboard, premium paper, OCR paper, coated paper, mirror-coated paper, capacitor paper, and paraffin paper.

[0399] Examples of the resin film include polyester film, polypropylene (PP) film, cellophane, acetate film, polycarbonate (PC) film, acrylic resin film, polyethylene terephthalate (PET) film, biaxially stretched polystyrene (OPS) film, biaxially stretched polypropylene (OPP) film, biaxially stretched nylon (ONy) film, polyvinyl chloride (PVC) film, polyethylene (PE) film and triacetate (TAC) film.

[0400] There is no particular limitation on the inkjet recording method as long as it is a method that can record images. It can be a well-known method, such as a charge control method that utilizes electrostatic induction force to eject ink, a drop-on-demand inkjet method (pressure pulse method) that utilizes the vibration pressure of a piezoelectric element, an acoustic inkjet method that converts an electrical signal into a sound beam to irradiate the ink and utilizes radiation pressure to eject the ink, and a thermal inkjet (Bubble Jet (registered trademark)) method that heats the ink to form bubbles and utilizes the generated pressure.

[0401] As an inkjet recording method, the following inkjet recording method can be particularly effectively used: using the method described in Japanese Patent Application Laid-Open No. 54-59936, the ink subjected to thermal energy undergoes a rapid volume change, and the ink is ejected from the nozzle by the force generated by the state change.

[0402] In addition, regarding the inkjet recording method, the method described in paragraphs 0093 to 0105 of Japanese Patent Application Laid-Open No. 2003-306623 can also be referred to.

[0403] As inkjet heads used for inkjet recording, there are a reciprocating method that uses a short column head to record while scanning the head in the width direction of the substrate, and a row method that uses a row head with recording elements arranged in the entire area corresponding to one side of the substrate.

[0404] In the line method, patterning can be performed on the entire surface of the substrate by scanning the substrate in a direction intersecting the arrangement direction of the recording elements, and a transport system such as a carriage for scanning short heads is unnecessary.

[0405] Furthermore, since there is no need to perform complicated scanning control on the movement of the carriage and the substrate, only the substrate moves, and thus the recording speed can be increased compared to the reciprocating method.

[0406] From the viewpoint of obtaining a high-definition image, the ejection amount of the ink ejected from the inkjet head is preferably 1 pL (picoliter) to 20 pL, and more preferably 1.5 pL to 10 pL.

[0407] The inkjet recording method of the present invention may include other steps in addition to the step of recording an image on a substrate by inkjet recording. As other steps, for example, a step of drying the image after recording the image can be cited. In addition, when the ink contains a polymerizable compound, the image recording method of the present invention may include a step of irradiating active energy rays.

[0408] Example

[0409] Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples unless it exceeds the gist of the present invention.

[0410] Compounds 1 to 5 were synthesized with reference to the Examples of International Publication No. 2022 / 049862.

[0411] [Chemical formula 32]

[0412]

[0413] Compounds 1 to 5 are all pigment compounds represented by Formula 1, and the basic core 1 and the basic core 2 have the same structure. 1, basic nucleus 1 and basic nucleus 2 (in the table, described as "two basic nuclei in Cy"), and X 1 .

[0414] [Table 1]

[0415]

[0416] <Comparative Compound 1 to Comparative Compound 2>

[0417] The structures of Comparative Compounds 1 and 2 are as follows.

[0418] (Comparative Compound 1)

[0419] [Chemical formula 33]

[0420]

[0421] (Comparative Compound 2)

[0422] [Chemical formula 34]

[0423]

[0424] <Ink Preparation>

[0425] The components were mixed to obtain the compositions shown in Tables 2 to 5. Furthermore, 2.5 g of zirconia beads having a diameter of 0.5 mm were added and dispersed for 6 hours using a test tube mixer Se-08 (manufactured by TAITEC CORPORATION). After dispersion, the beads were separated using a nylon filter cloth having a diameter of 67 μm to obtain an ink.

[0426] The details of the components other than the pigment compound described in Tables 2 to 5 are as follows.

[0427] (Dispersant)

[0428] Dispersant P1: a polymer containing a phosphoric acid group and an ethylene oxide chain (product name "SOLSPERSE 41000", manufactured by The Lubrizol Corporation, solid content concentration 100 mass %), acid value 50 mgKOH / g

[0429] Dispersant P2: a polymer containing a carboxyl group and an oxyethylene chain and containing a structural unit derived from styrene (product name: "DISPERBYK-190", manufactured by BYK, solid content concentration: 40% by mass), acid value: 10 mgKOH / g

[0430] Dispersant P3: a polymer containing carboxyl groups and ethylene oxide chains and containing structural units derived from styrene (product name: "DISPERBYK-191", manufactured by BYK, solid content concentration: 98%), acid value: 30 mgKOH / g

[0431] Dispersant P4: A polymer containing carboxyl groups and ethylene oxide chains and containing structural units derived from styrene, synthesized by the following method

[0432] As raw material monomers, the following compounds were prepared.

[0433] Styrene: 45 parts by mass

[0434] Styrene macromonomer (product name "AS-6S", manufactured by TOAGOSEI CO., LTD.): 20 parts by mass

[0435] Methacrylic acid: 15 parts by mass

[0436] Polypropylene glycol monomethacrylate (number of repetitions of PO chain = 9) (product name "BLEMMER PP-500", manufactured by NOFCORPORATION): 10 parts by mass

[0437] Poly(ethylene glycol-propylene glycol) monomethacrylate (product name "BRENMER 50PEP-300", manufactured by NOFCORPORATION): 10 parts by mass

[0438] 20 parts by mass of methyl ethyl ketone, 10% by mass of the above-mentioned raw material monomers, and 0.03 parts by mass of a chain transfer agent (2-mercaptoethanol) were placed and mixed in a reaction container A. The reaction container A was substituted with nitrogen.

[0439] Then, 90% by mass of the raw material monomers, 0.27 parts by mass of a chain transfer agent (2-mercaptoethanol), 60 parts by mass of methyl ethyl ketone, and 1.2 parts by mass of 2,2'-azobis(2,4-dimethylvaleronitrile) were placed and mixed in a reaction container B. The mixed solution was added to a dropping device and replaced with nitrogen.

[0440] The reaction vessel A was heated to 65°C, and the mixed solution in the dropping device was added dropwise over 3 hours under stirring in a nitrogen atmosphere. After the addition, the mixture was left to stand for 2 hours, and a solution of 0.3 parts by mass of 2,2'-azobis(2,4-dimethylvaleronitrile) dissolved in 5 parts by mass of methyl ethyl ketone was added.

[0441] The mixture was left to stand at 65° C. for 2 hours and further left to stand at 70° C. for 2 hours to obtain a polymer solution. The solvent was dried under reduced pressure to separate the polymer. The separated polymer was used as dispersant P4.

[0442] Dispersant P5: A polymer containing a carboxyl group and an ethylene oxide chain and containing a structural unit derived from styrene, synthesized by the following method

[0443] As raw material monomers, the following compounds were prepared.

[0444] Styrene: 30 parts by mass

[0445] Styrene macromonomer (product name "AS-6S", manufactured by TOAGOSEI CO., LTD.): 20 parts by mass

[0446] Methacrylic acid: 30 parts by mass

[0447] Polypropylene glycol monomethacrylate (number of repetitions of PO chain = 9) (product name "BLEMMER PP-500", manufactured by NOFCORPORATION): 10 parts by mass

[0448] Poly(ethylene glycol-propylene glycol) monomethacrylate (product name "BRENMER 50PEP-300", manufactured by NOFCORPORATION): 10 parts by mass

[0449] 20 parts by mass of methyl ethyl ketone, 10% by mass of the above-mentioned raw material monomers, and 0.03 parts by mass of a chain transfer agent (2-mercaptoethanol) were placed and mixed in a reaction container A. The reaction container A was substituted with nitrogen.

[0450] Then, 90% by mass of the raw material monomers, 0.27 parts by mass of a chain transfer agent (2-mercaptoethanol), 60 parts by mass of methyl ethyl ketone, and 1.2 parts by mass of 2,2'-azobis(2,4-dimethylvaleronitrile) were placed and mixed in a reaction container B. The mixed solution was added to a dropping device and replaced with nitrogen.

[0451] The reaction vessel A was heated to 65°C, and the mixed solution in the dropping device was dripped over 3 hours under stirring in a nitrogen atmosphere. After the dripping, it was left to stand for 2 hours, and a solution obtained by dissolving 0.3 parts by mass of 2,2'-azobis(2,4-dimethylvaleronitrile) in 5 parts by mass of methyl ethyl ketone was added. The mixture was left to stand at 65°C for 2 hours and further at 70°C for 2 hours to obtain a polymer solution. The solvent was dried under reduced pressure to separate the polymer. The separated polymer was used as dispersant P5.

[0452] Dispersant Q1: Polyacrylic acid not containing an ethylene oxide chain (product name "ARONT-50", manufactured by TOAGOSEICO., LTD.)

[0453] Dispersant Q2: A polymer containing no acidic functional group and containing an ethylene oxide chain (product name: "DISPERBYK-193", manufactured by BYK, solid content concentration: 40% by mass)

[0454] Tables 2 to 5 show the content of the structural unit derived from at least one selected from the group consisting of styrene and styrene derivatives contained in the dispersant.

[0455] The content of the dispersant shown in Tables 2 to 5 is the content of the solid content contained in each dispersant.

[0456] (Water-soluble organic solvent)

[0457] PG: Propylene glycol

[0458] 1,3BD: 1,3-Butanediol

[0459] ·DEGmEE: Diethylene glycol monoethyl ether

[0460] EGmHE: Ethylene glycol monohexyl ether

[0461] Tables 2 to 5 show the SP values ​​of the water-soluble organic solvents.

[0462] (Surfactant)

[0463] Acetylene glycol surfactant (product name "OLFINE E1010", manufactured by Nissin Chemical Co., Ltd.)

[0464] <Production of image records>

[0465] The prepared ink was filtered using a 5 μm filter. The filtered ink was filled into an ink cartridge attached to an inkjet recording device (product name "DMP-2850", manufactured by FUJIFILM DIMATIX, Inc.). As a substrate, OKT104 coated paper (manufactured by OJIPAPER CO., LTD.) was prepared. After the ink was sprayed onto the substrate under the conditions of a resolution of 600 dpi, a spray volume of 10 pL, a nozzle temperature of 25°C, and a dot percentage of 100%, an image record was obtained by drying at 120°C for 10 seconds using a dryer.

[0466] Using the obtained image records, invisibility was evaluated.

[0467] The obtained ink was used to evaluate dispersibility and long-wavelength absorption. The evaluation method was as follows.

[0468] [Invisibility]

[0469] The reflectance of the image recorded object was measured in the wavelength range of 400 nm to 1100 nm using a near-infrared visible spectrophotometer V-770 (manufactured by JASCO Corporation) equipped with an integrating sphere unit ISN-923 (manufactured by JASCO Corporation).

[0470] The K / S values ​​were calculated using the lowest reflectance A (%) among the reflectances at wavelengths of 900 nm or longer and the reflectance B (%) at a wavelength of 600 nm according to the following formula.

[0471] K / S(A)={1-(reflectivity A / 100)} 2 / {2×(reflectivity A / 100)}

[0472] K / S(B)={1-(reflectivity B / 100)} 2 / {2×(reflectivity B / 100)}

[0473] Based on the calculated ratio W of the K / S value, the invisibility was evaluated.

[0474] Ratio W = {K / S(A)} ÷ {K / S(B)}

[0475] The evaluation criteria are as follows.

[0476] A: The ratio W is 55 or more.

[0477] B: The ratio W is 45 or more and less than 55.

[0478] C: The ratio W is 30 or more and less than 45.

[0479] D: The ratio W is less than 30.

[0480] [Dispersibility]

[0481] The prepared ink was diluted 1000 times with ultrapure water, and the absorbance of the diluted ink was measured in the wavelength range of 400 nm to 1100 nm using an infrared visible spectrophotometer (product name "V-770", manufactured by JASCO Corporation).

[0482] The dispersibility was evaluated based on the highest absorbance among absorbances at wavelengths of 900 nm or longer.

[0483] The evaluation criteria are as follows.

[0484] A: The absorbance is 2.00 or more.

[0485] B: The absorbance is 1.50 or more and less than 2.00.

[0486] C: The absorbance is 0.95 or more and less than 1.50.

[0487] D: Absorbance is less than 0.95.

[0488] [Long wavelength absorption]

[0489] The prepared ink was diluted 1000 times with ultrapure water, and the absorbance of the diluted ink was measured in the wavelength range of 400 nm to 1100 nm using an infrared visible spectrophotometer (product name "V-770", manufactured by JASCO Corporation).

[0490] Among the absorbances with respect to wavelengths longer than 900 nm, the maximum absorbance C and the absorbance D at a wavelength of 850 nm were used to calculate the ratio Y according to the following formula. Based on the ratio Y, the long-wavelength absorbency was evaluated.

[0491] Ratio Y = (absorbance C) ÷ (absorbance D)

[0492] The evaluation criteria are as follows.

[0493] A: The ratio Y is 5.5 or more.

[0494] B: The ratio Y is 2 or more and less than 5.5.

[0495] C: The ratio Y is 0.9 or more and less than 2.

[0496] D: The ratio Y is less than 0.9.

[0497] The evaluation results are shown in Tables 2 to 5.

[0498] In Tables 2 to 5, the SP value of the mixed solvent refers to the SP value of the mixed solvent composed of water and a water-soluble organic solvent. B represents the ratio (mass %) of the content of the water-soluble organic solvent to the total content of water and the water-soluble organic solvent. A represents the SP value (MPa) of the water-soluble organic solvent. 1 / 2 ). “Dispersant / pigment compound” refers to the mass ratio of the content of the dispersant to the content of the pigment compound.

[0499] [Table 2]

[0500]

[0501] [Table 3]

[0502]

[0503] [Table 4]

[0504]

[0505] [Table 5]

[0506]

[0507] It can be seen that Examples 1 to 22 contain the pigment compound represented by Formula 1, a dispersant, a water-soluble organic solvent and water, and the dispersant is a polymer containing an acidic functional group and an ethylene oxide chain, so the invisibility is excellent and the infrared absorption ability is maintained longer than before.

[0508] It is understood that in Comparative Examples 1 and 3, no dispersant is included, and the invisibility, dispersibility, and long-wavelength absorption are poor.

[0509] It is understood that in Comparative Examples 2 and 3, since the pigment compound represented by Formula 1 is not included, the invisibility, dispersibility, and long-wavelength absorption are poor.

[0510] It is understood that in Comparative Example 5, the dispersant does not contain an ethylene oxide chain, and the invisibility, dispersibility, and long-wavelength absorption are poor.

[0511] It can be seen that in Comparative Example 6, the dispersant does not include an acidic functional group, and the invisibility, dispersibility, and long-wavelength absorption are poor.

[0512] It is understood that in Example 3, since the dispersant is a polymer including a structural unit derived from at least one selected from the group consisting of styrene and styrene derivatives, the invisibility, dispersibility, and long-wavelength absorption are superior to those in Example 1.

[0513] It is found that in Example 14, the content of the structural unit derived from at least one selected from the group consisting of styrene and styrene derivatives is 60 mol% or less relative to the total amount of the dispersant, and therefore the invisibility, dispersibility and long-wavelength absorption are superior to those of Example 13.

[0514] It can be seen that in Example 21, the SP value of the mixed solvent is 40.0 MPa 1 / 2 As above, compared with Example 22, the invisibility and long-wavelength absorption are excellent.

[0515] It is understood that in Example 20, since B is 10 or more and "1.6×A-7" or less, the invisibility is excellent compared with Example 21.

[0516] It is understood that in Example 18, since B is 10 or more and "1.6×A-12" or less, the long-wavelength absorptivity is excellent compared with that in Example 19.

[0517] It is understood that in Example 19, since the ratio of the water-soluble organic solvent to the total content of water and the water-soluble organic solvent is 15% by mass to 35% by mass, the dispersibility is superior to that of Example 20.

Claims

1. An inkjet ink comprising a pigment compound represented by the following formula 1, a dispersant, a water-soluble organic solvent, and water, The dispersant is a polymer containing an acidic functional group and an ethylene oxide chain, In formula 1, L 1 represents a methine chain consisting of an odd number of methines, R 1 and R 2 Each independently represents an aliphatic group or an aromatic group, T 1 and T 2 Each independently represents a non-metallic atom group forming a 5-membered or 6-membered nitrogen-containing heterocyclic ring which may be fused, Cy is an anion part, and X 1 represents an organic cation represented by the following formula 2-1, formula 2-2 or formula 2-3, or an organic cation having a structure represented by formula 2-4, and n represents a non-zero number required for neutralizing the charge, In formula 2-1, A 11 and A 12 Each independently represents a nitrogen atom or a phosphorus atom, and B 11 Each independently represents a divalent linking group, R 1a , R 1b , R 1c , R 1d 、E 11 and E 12 Each independently represents an aliphatic group or an aromatic group, R 1a , R 1b , R 1c and R 1d may be bonded to each other to form a ring, m1 is an integer greater than 1, In formula 2-2, A 21 , A 22 and A 23 Each independently represents a nitrogen atom or a phosphorus atom, and B 21 and B 22 Each independently represents a divalent linking group, R 2a and R 2b Each independently represents an aliphatic group or an aromatic group, m2 is an integer greater than 0, G 21 Indicates that the ring contains A 21 The non-metallic atom group of the aromatic ring, G 22 Indicates that the ring contains A 23 The aromatic ring of the non-metallic atom group, In formula 2-3, A 31 and A 32 Each independently represents a nitrogen atom or a phosphorus atom, and B 31 represents a divalent linking group, R 3a and R 3b Each independently represents an aliphatic group or an aromatic group, G 31 Indicates that the ring contains A 31 The non-metallic atom group of the aromatic ring, G 32 Indicates that the ring contains A 32 The aromatic ring of the non-metallic atom group, In formula 2-4, A 41 Each independently represents a nitrogen atom or a phosphorus atom, and B 41 Each independently represents a single bond or a divalent linking group, R 4a , R 4b and R 4c Each independently represents an aliphatic group or an aromatic group, and E 41 and E 42 Each independently represents a single bond or an aliphatic group, R 4a , R 4b and R 4c One of them can be combined with E 41 or E 42 They are bonded to form a ring, and m4 is an integer greater than or equal to 2.

2. The inkjet ink according to claim 1, wherein The dispersant further includes a structural unit derived from at least one selected from the group consisting of styrene and styrene derivatives.

3. The inkjet ink according to claim 2, wherein: The content of the structural unit derived from at least one selected from the group consisting of styrene and styrene derivatives is 1 mol % to 60 mol % based on the total amount of the dispersant.

4. The inkjet ink according to any one of claims 1 to 3, wherein The mass ratio of the content of the dispersant to the content of the pigment compound represented by Formula 1 is 0.1 to 3.

5. The inkjet ink according to any one of claims 1 to 3, wherein The SP value of the mixed solvent formed by the water and the water-soluble organic solvent is 40.0 MPa 1 / 2 ~47.0MPa 1 / 2 .

6. The inkjet ink according to any one of claims 1 to 3, wherein When the SP value of the water-soluble organic solvent is set to A[MPa 1 / 2 ]、 When the ratio of the water-soluble organic solvent to the total content of the water and the water-soluble organic solvent is represented by B mass %, A and B satisfy the following formula T1: 10≤B≤1.6×A-7(T1).

7. The inkjet ink according to claim 6, wherein: A and B satisfy the following formula T2: 10≤B≤1.6×A-12(T2).

8. The inkjet ink according to any one of claims 1 to 3, wherein The ratio of the water-soluble organic solvent to the total content of the water and the water-soluble organic solvent is 15% by mass to 35% by mass.

9. The inkjet ink according to any one of claims 1 to 3, wherein In the above formula 1, Cy is represented by the following formula 4: In formula 4, Y 1 and Y 2 Represent CR independently 3 R 4 -, -O-, -S-, -Se-, or -NR 5 -, R 3 , R 4 and R 5 Each independently represents a hydrogen atom, an aliphatic group or an aromatic ring group, R 3 and R 4 can bond to each other to form a ring, A 1 and A 2 Each independently represents a non-metallic atom group forming an aromatic ring or an aromatic heterocyclic ring, and L 2 Each independently represents a methine chain consisting of 1, 2 or 3 methine groups, L 2 No substituent, R 6 and R 7 Each independently represents a hydrogen atom or an aliphatic group, R 6 and R 7 can be linked to each other to form a ring, R 8 It is represented by the following formula A, -S A -T A Formula A In formula A, S A represents a single bond, alkylene, alkenylene, alkynylene, -O-, -S-, -NR L1 -, -C(=O)-, -C(=O)O-, -C(=O)NR L1 -、-S(=O)2-、-OR L2 - or a group consisting of at least two of these, R L1 Each independently represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group or a monovalent heterocyclic group, and R L2 represents an alkylene group, an arylene group or a divalent heterocyclic group, T A represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, a monovalent heterocyclic group, a cyano group, a hydroxyl group, a formyl group, a carboxyl group, an amino group, a thiol group, a sulfone group, a phosphoryl group, a boryl group, a vinyl group, an ethynyl group, a trialkylsilyl group or a trialkoxysilyl group. 10 . An inkjet recording method comprising the step of applying the inkjet ink according to claim 1 to a substrate by an inkjet recording method.

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