Yellow-azo-pigment-containing coloring composition and method for producing same

Abstract

[Problem] To provide a coloring composition that is an aqueous coloring composition using a yellow azo pigment and is excellent in dispersion stability. [Solution] The coloring composition contains a yellow azo pigment, a dispersant, and an aqueous dispersion medium and is characterized in that the dispersant is a neutralized product of a block copolymer having an A block having a structural unit (a-1) having a group represented by formula (1) and a structural unit (a-2) having an acidic group and a B block having a structural unit (b-1) having a nitrogen-containing heterocyclic group and a structural unit (b-2) having an aliphatic hydrocarbon group, the content of the structural unit (b-1) of the block copolymer is 51-99 mass% in the B block, the acid value of the block copolymer is 50 mg KOH / g or more, and more than 50 mol% of the acidic groups of the structural unit (a-2) of the block copolymer are neutralized in the dispersant.　(1) *-(R12O)m1-R11 [In formula (1), m1 represents an integer of 2-30, R11 represents a hydrogen atom or an alkyl group, R12 represents an alkylene group, and * represents a bond.]

Description

Yellow azo pigment-containing coloring composition and method for producing the same

[0001] The present invention relates to a coloring composition containing a yellow azo pigment and a method for producing the same.

[0002] The recording method using an inkjet printer involves generating ink droplets from a fine nozzle, ejecting them onto a recording material such as paper, film, or cloth, and allowing them to adhere to the material. This method allows for easy and inexpensive image creation, and is therefore applied to a variety of printing fields, including photography, various types of printing, and special printing such as color filters.

[0003] Ink (coloring composition) used in inkjet printers is composed of a colorant, a dispersion medium, and additives such as surfactants, if necessary. Two types of colorants are known: water-soluble dyes and substantially water-insoluble colorants such as pigments, disperse dyes, and oil-soluble dyes. Of these, images recorded using water-soluble dyes as colorants have excellent image quality, such as clarity, while images recorded using water-insoluble colorants (especially pigments) have excellent fastness to light, ozone, water, and other factors. Due to these advantages, inkjet inks containing water-insoluble colorants are increasingly being used. Meanwhile, water-based inks are in demand for environmental and safety reasons. However, when using water-insoluble colorants in inkjet inks, the colorants must be micronized and then uniformly dispersed in the ink. Therefore, selecting a dispersant is important to achieve uniform dispersion.

[0004] Ink is usually used in four basic colors: yellow, magenta, cyan, and black. Of these, yellow inkjet water-based inks generally use yellow azo pigments such as Pigment Yellow 74 because of their high vividness and coloring power. Water-based inks using yellow azo pigments have been proposed that have improved dispersion stability, heat resistance, weather resistance, etc.

[0005] For example, Patent Document 1 discloses an aqueous pigment dispersion for inkjet recording containing a yellow azo pigment (A), an aromatic group-containing polymer (B), and an alkali metal hydroxide (C), in which the aromatic group-containing polymer (B) is obtained by crosslinking an aromatic group-containing water-insoluble polymer (a) having an acid value of 200 mgKOH / g or more and 320 mgKOH / g or less with a water-insoluble polyfunctional epoxy compound (b), and the acid value, degree of neutralization, and degree of crosslinking of the water-insoluble polymer (a) satisfy the following relationship: [(100 - degree of neutralization - degree of crosslinking) / 100] x (acid value of water-insoluble polymer (a)) is -30 mgKOH / g or more and 130 mgKOH / g or less (see Patent Document 1 (Claim 1, paragraph 0011)).

[0006] JP 2018-109095 A

[0007] However, the dispersant used in the aqueous pigment dispersion described in Patent Document 1 does not have sufficient dispersion stability. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an aqueous coloring composition that uses a yellow azo pigment as a colorant and has excellent dispersion stability.

[0008] The coloring composition of the present invention, which has been able to solve the above-mentioned problems, is a coloring composition containing a yellow azo pigment, a dispersant, and an aqueous dispersion medium, wherein the dispersant is a neutralized product of a block copolymer having an A block containing a structural unit (a-1) having a group represented by Formula (1) and a structural unit (a-2) having an acidic group, and a B block containing a structural unit (b-1) having a nitrogen-containing heterocyclic group and a structural unit (b-2) having an aliphatic hydrocarbon group, wherein the content of the structural unit (b-1) in the block copolymer is 51% to 99% by mass relative to 100% by mass of the B block, the acid value of the block copolymer is 50 mgKOH / g or more, and more than 50 mol % of the acidic groups in the structural unit (a-2) of the block copolymer have been neutralized. 12 O) m1 -R 11 (1) [In formula (1), m1 represents an integer of 2 to 30. R 11represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 12 represents an alkylene group having 1 to 3 carbon atoms. 12 may be the same or different. * represents a bond.]

[0009] The reason why the use of a neutralized product of a block copolymer having a specific structure as a dispersant in the colored composition of the present invention improves the dispersibility of the yellow azo pigment is believed to be as follows: The neutralized product of the block copolymer contained as a dispersant in the colored composition of the present invention has an A block that has a structural unit (a-1) having a group represented by formula (1) and a structural unit (a-2) having an acidic group, and more than 50 mol % of the acidic groups in the structural unit (a-2) are neutralized, thereby increasing affinity with the aqueous dispersion medium, and the structural unit (b-1) having a nitrogen-containing heterocyclic group and the structural unit (b-2) having an aliphatic hydrocarbon group contained in the B block are adsorbed to the yellow azo pigment. Therefore, the colored composition of the present invention has high dispersibility of the yellow azo pigment.

[0010] According to the present invention, it is possible to obtain an aqueous colored composition that uses a yellow azo pigment as a colorant and has excellent dispersion stability.

[0011] Hereinafter, an example of a preferred embodiment of the present invention will be described. However, the following embodiment is merely an example, and the present invention is not limited to the following embodiment.

[0012] <Definitions> In this specification, "(meth)acrylic" means "at least one of acrylic and methacrylic". "(meth)acrylate" means "at least one of acrylate and methacrylate". "(meth)acryloyl" means "at least one of acryloyl and methacryloyl". "(meth)acrylic monomer" means "a monomer having a (meth)acryloyl group in the molecule", and includes "(meth)acrylate". "Vinyl monomer" means a monomer having a radically polymerizable carbon-carbon double bond in the molecule, and includes "(meth)acrylic monomer" and "(meth)acrylate". (Meth)acrylate is an ester compound in which the hydrogen atom of the carboxy group of (meth)acrylic acid is substituted with an organic group.

[0013] In this specification, a "structural unit derived from a (meth)acrylate" means a "structural unit in which a radically polymerizable carbon-carbon double bond of a (meth)acrylate is polymerized to form a carbon-carbon single bond." A "structural unit derived from a (meth)acrylic monomer" means a "structural unit in which a radically polymerizable carbon-carbon double bond of a (meth)acrylic monomer is polymerized to form a carbon-carbon single bond." A "structural unit derived from a vinyl monomer" means a structural unit in which a radically polymerizable carbon-carbon double bond of a vinyl monomer is polymerized to form a carbon-carbon single bond.

[0014] In this specification, when it is stated that "X to Y" (X and Y are any numbers), it means "X or more, Y or less." Furthermore, when it is stated that "X or more" (X is any number), it also means "X or more than X," and when it is stated that "Y or less" (Y is any number), it also means "Y or less than Y." Furthermore, "X and / or Y (X and Y are any configurations)" means "at least one of X and Y," and it can mean three things: "X only," "Y only," or "X and Y."

[0015] In this specification, "A block" can be rephrased as "A segment", and "B block" can be rephrased as "B segment".

[0016] [Block copolymer] The block copolymer used as the dispersant for the colored composition of the present invention will be described. In this specification, the content of each structural unit in the block copolymer, the acid value, the weight average molecular weight, and the molecular weight distribution are values ​​when all of the acidic groups in the block copolymer are in an unneutralized state.

[0017] The block copolymer has an A block containing a structural unit (a-1) having a group represented by formula (1) and a structural unit (a-2) having an acidic group, and a B block containing a structural unit (b-1) having a nitrogen-containing heterocyclic group and a structural unit (b-2) having an aliphatic hydrocarbon group. By forming the block copolymer, the structural units of the A block and the B block are localized, allowing them to efficiently interact favorably with the yellow azo pigment colorant and the aqueous dispersion medium, thereby improving dispersion performance.

[0018] (A Block) The A block contains a structural unit (a-1) having a group represented by formula (1) and a structural unit (a-2) having an acidic group.

[0019] (Structural Unit (a-1)) The A block contains a structural unit (a-1) having a group represented by formula (1). The presence of the structural unit (a-1) improves the affinity of the A block with the aqueous dispersion medium that is the dispersion medium for the A block. The structural unit (a-1) may be used alone or in combination of two or more types.

[0020] *-(R 12 O) m1 -R 11 (1) [In formula (1), R 11 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 12 represents an alkylene group having 1 to 3 carbon atoms. m1 represents an integer of 2 to 30. 12 may be the same or different. * represents a bond.]

[0021] The R 11 The alkyl group having 1 to 3 carbon atoms represented by may be either linear or branched, but is preferably linear. 11Specific examples of the alkyl group having 1 to 3 carbon atoms represented by the formula (I) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, etc. 12 The alkylene group having 1 to 3 carbon atoms represented by may be either linear or branched, but is preferably linear. 12 Specific examples of the alkylene group having 1 to 3 carbon atoms represented by the formula (R) include a methylene group, an ethylene group, a trimethylene group, and a propane-1,2-diyl group. 12 is preferably an ethylene group or a trimethylene group. The m1 is 2 or more, preferably 5 or more, and 30 or less, preferably 20 or less, and more preferably 15 or less.

[0022] In the structural unit (a-1), the group represented by formula (1) is introduced into a side chain portion. The group represented by formula (1) may be directly bonded to a carbon atom constituting the main chain, or may be bonded via another atom. The group represented by formula (1) is preferably bonded to a carbon atom constituting the main chain via an ester bond (-CO-O-) or an amide bond (-CO-NH-). The bonding direction of the amide group or ester group is not particularly limited. Examples of monomers that form the structural unit (a-1) include compounds having one carbon-carbon double bond and one group represented by formula (1) in the molecule.

[0023] The structural unit (a-1) is preferably a structural unit represented by formula (2).

[0024] [In formula (2), R 21 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 22 represents an alkylene group having 1 to 3 carbon atoms. 23 represents a hydrogen atom or a methyl group. m2 represents an integer of 2 to 30. 22 may be the same or different.

[0025] The R 21 The alkyl group having 1 to 3 carbon atoms represented by may be either linear or branched, but is preferably linear. 21Specific examples of the alkyl group having 1 to 3 carbon atoms represented by the formula (I) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, etc. 22 The alkylene group having 1 to 3 carbon atoms represented by may be either linear or branched, but is preferably linear. 22 Specific examples of the alkylene group having 1 to 3 carbon atoms represented by the formula (I) include a methylene group, an ethylene group, a trimethylene group, and a propane-1,2-diyl group. 22 is preferably an ethylene group or a trimethylene group. The m2 is 2 or more, preferably 5 or more, and 30 or less, preferably 20 or less, and more preferably 15 or less. 23 is preferably a hydrogen atom.

[0026] Examples of the monomer constituting the structural unit represented by the formula (2) include (meth)acrylates having a polyalkylene glycol structure. The polyalkylene glycol portion may be, for example, a mixture of ethylene oxide and propylene oxide. Examples of the (meth)acrylate having a polyalkylene glycol structure include (meth)acrylates having a polyethylene glycol structure such as polyethylene glycol (degree of polymerization = 2 to 30) methyl ether (meth)acrylate, polyethylene glycol (degree of polymerization = 2 to 30) ethyl ether (meth)acrylate, polyethylene glycol (degree of polymerization = 2 to 30) propyl ether (meth)acrylate, and polyethylene glycol (degree of polymerization = 2 to 30) mono(meth)acrylate; and (meth)acrylates having a polypropylene glycol structural unit such as polypropylene glycol (degree of polymerization = 2 to 30) methyl ether (meth)acrylate, polypropylene glycol (degree of polymerization = 2 to 30) ethyl ether (meth)acrylate, polypropylene glycol (degree of polymerization = 2 to 30) propyl ether (meth)acrylate, and polypropylene glycol (degree of polymerization = 2 to 30) mono(meth)acrylate.

[0027] The content of the structural unit (a-1) is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more, and is preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less, based on 100% by mass of the A block. When the content of the structural unit (a-1) is within the above range, the affinity with the aqueous dispersion medium is further increased.

[0028] (Structural Unit (a-2)) The A block contains a structural unit (a-2) having an acidic group. When the A block contains a predetermined amount of the structural unit (a-2), the affinity with the aqueous dispersion medium, which is the dispersion medium, becomes better. The structural unit (a-2) may be used alone or in combination of two or more types.

[0029] Examples of the acidic group contained in the structural unit (a-2) having an acidic group include a carboxy group (—COOH), a sulfonic acid group (—SOH), a phosphoric acid group (—OPOH), a phosphonic acid group (—POH), and a phosphinic acid group (—POH). A carboxy group or a sulfonic acid group is preferred, and a carboxy group is more preferred.

[0030] The structural unit (a-2) having an acidic group is preferably a structural unit represented by formula (3).

[0031] [In formula (3), R 31 represents a single bond or a divalent organic group. 32 represents a hydrogen atom or a methyl group. 3 represents an acidic group.

[0032] In formula (3), R 31 Examples of the divalent organic group represented by the formula (I) include an alkylene group, an arylene group, an amide group (—CONH—R 311 - group), ester group (-COO-R 312 - group), and preferably -CONH-R 311 - group or -COO-R 312 The bonding direction of the amide group and the ester group is not particularly limited, but the bonding mode of the amide group is C—CO—NH—R 311 -Y 3The bonding mode of the ester group is preferably C—CO—O—R 312 -Y 3 is preferred.

[0033] The R 311 is preferably an alkylene group (-R 3111 - group) or ester group (-R 3112 -O-CO-R 3113 The bonding direction of the ester group is not particularly limited, but the bonding mode of the ester group is preferably -R 3112 -O-CO-R 3113 -Y 3 The R 3111 is preferably an alkylene group, more preferably a linear alkylene group or a branched alkylene group, and even more preferably a linear alkylene group having 1 to 10 carbon atoms or a branched alkylene group having 3 to 10 carbon atoms. Specific examples include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, and a tert-butylene group. 3112 is preferably an alkylene group, more preferably a linear alkylene group or a branched alkylene group, even more preferably a linear alkylene group having 1 to 10 carbon atoms or a branched alkylene group having 3 to 10 carbon atoms, and even more preferably a linear alkylene group having 1 to 4 carbon atoms. Specific examples include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, and a heptamethylene group. 3113 is preferably a linear alkylene group, a branched alkylene group, a cyclic alkylene group, or an arylene group, more preferably a linear alkylene group having 1 to 10 carbon atoms, a branched alkylene group having 3 to 10 carbon atoms, a cyclic alkylene group having 6 to 10 carbon atoms, or an arylene group having 6 to 10 carbon atoms, and even more preferably a linear alkylene group having 1 to 4 carbon atoms. Specific examples include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, and a heptamethylene group.

[0034] The R 312is preferably an alkylene group (-R 3121 - group) or ester group (-R 3122 -O-CO-R 3123 The bonding direction of the ester group is not particularly limited, but the bonding mode of the ester group is preferably -R 3122 -O-CO-R 3123 -Y 3 The R 3121 is preferably an alkylene group, more preferably a linear alkylene group or a branched alkylene group, and even more preferably a linear alkylene group having 1 to 10 carbon atoms or a branched alkylene group having 3 to 10 carbon atoms. Specific examples include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, and a tert-butylene group. 3122 is preferably an alkylene group, more preferably a linear alkylene group or a branched alkylene group, even more preferably a linear alkylene group having 1 to 10 carbon atoms or a branched alkylene group having 3 to 10 carbon atoms, and even more preferably a linear alkylene group having 1 to 4 carbon atoms. Specific examples include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, and a heptamethylene group. 3123 is preferably an alkylene group or an arylene group, more preferably a linear alkylene group, a branched alkylene group, a cyclic alkylene group or an arylene group, even more preferably a linear alkylene group having 1 to 10 carbon atoms, a branched alkylene group having 3 to 10 carbon atoms, a cyclic alkylene group having 6 to 10 carbon atoms or an arylene group having 6 to 10 carbon atoms, and even more preferably a linear alkylene group having 1 to 4 carbon atoms. Specific examples include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, and a heptamethylene group.

[0035] Y in formula (3) 3Examples of the acidic group represented by the formula (I) include a carboxy group, a sulfonic acid group, a phosphoric acid group, a phosphonic acid group, and a phosphinic acid group, and a carboxy group or a sulfonic acid group is preferred, with a carboxy group being more preferred.

[0036] The structural unit (a-2) having an acidic group is, in formula (3), R 31 is a single bond, R 32 is a hydrogen atom or a methyl group, Y 3 is a structural unit in which R is an acidic group; 31 is an amide group (-CONH-R 3111 - group), R 3111 is an alkylene group, R 32 is a hydrogen atom or a methyl group, Y 3 is a structural unit in which R is an acidic group; 31 is an ester group (-COO-R 3121 - group), R 3121 is an alkylene group, R 32 is a hydrogen atom or a methyl group, Y 3 is an acidic group; and R 31 is an ester group (-COO-R 312 - group), R 312 is an ester group (-R 3122 -O-CO-R 3123 - group), R 3122 is an alkylene group, R 3123 is an alkylene group or an arylene group, R 32 is a hydrogen atom or a methyl group, Y 3 is an acidic group.

[0037] The structural unit (a-2) is more preferably a structural unit represented by formula (31) and / or a structural unit represented by formula (32).

[0038] [In formula (31), R 32 represents a hydrogen atom or a methyl group. 3 represents an acidic group.

[0039] Y in formula (31) 3Examples of the acidic group represented by formula (31) include a carboxy group, a sulfonic acid group, a phosphoric acid group, a phosphonic acid group, and a phosphinic acid group, and a carboxy group or a sulfonic acid group is preferred, and a carboxy group is more preferred. 32 is preferably a hydrogen atom.

[0040] [In formula (32), R 32 represents a hydrogen atom or a methyl group. 33 represents an alkylene group. 3 represents an acidic group.

[0041] R in formula (32) 33 The alkylene group represented by the formula (32) is preferably a linear alkylene group or a branched alkylene group, and more preferably a linear alkylene group having 1 to 10 carbon atoms or a branched alkylene group having 3 to 10 carbon atoms. Specific examples include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, and a tert-butylene group. 3 Examples of the acidic group represented by R in formula (32) include a carboxy group, a sulfonic acid group, a phosphoric acid group, a phosphonic acid group, and a phosphinic acid group, and a carboxy group or a sulfonic acid group is preferred, with a carboxy group being more preferred. 32 is preferably a hydrogen atom.

[0042] The monomer that forms the structural unit (a-2) is preferably at least one selected from the group consisting of (meth)acrylic acid, vinyl sulfonic acid, 1-propene-2-sulfonic acid, vinyl phosphate, isopropenyl phosphate, vinylphosphonic acid, isopropenylphosphonic acid, vinylphosphinic acid, (1-methylethenyl)phosphinic acid, 2-((meth)acryloyloxy)ethyl hydrogen succinate, 2-carboxyethyl (meth)acrylate, 2-((meth)acryloyloxy)ethanesulfonic acid, (meth)acrylamido t-butylsulfonic acid, and 2-(phosphonooxy)ethyl (meth)acrylate, and more preferably (meth)acrylic acid or (meth)acrylamido t-butylsulfonic acid.

[0043] The content of the structural unit (a-2) is preferably 9% by mass or more, more preferably 11% by mass or more, and even more preferably 13% by mass or more, relative to 100% by mass of the A block, and is preferably 38% by mass or less, more preferably 36% by mass or less, and even more preferably 34% by mass or less. When the content of the structural unit (a-2) is within the above range, the viscosity stability of the colored composition becomes even better.

[0044] The total content of the structural unit (a-1) and the structural unit (a-2) in 100% by mass of the A block is preferably 19% by mass or more, more preferably 26% by mass or more, and even more preferably 33% by mass or more. When the total content of the structural unit (a-1) and the structural unit (a-2) is within the above range, the affinity with the aqueous dispersion medium is further increased.

[0045] The mass ratio (a-1 / a-2) of the structural unit (a-1) to the structural unit (a-2) in the A block is preferably 0.25 or more, more preferably 0.30 or more, and even more preferably 0.35 or more, and is preferably 7.8 or less, more preferably 6.7 or less, and even more preferably 5.6 or less. When the mass ratio (a-1 / a-2) is within the above range, the viscosity stability of the colored composition becomes even better.

[0046] The A block may be composed of only the structural unit (a-1) and the structural unit (a-2), or may contain other structural units.

[0047] (Other Structural Units) The A block may contain structural units other than the structural unit (a-1) and the structural unit (a-2) to the extent that the effects of the present invention are not impaired. Examples of the other structural units include structural units derived from (meth)acrylic monomers and structural units derived from vinyl monomers other than (meth)acrylic monomers. One type of other structural unit may be used alone, or two or more types may be used in combination.

[0048] The (meth)acrylic monomer may be one or more vinyl monomers selected from the group consisting of (meth)acrylates having a chain alkyl group, (meth)acrylates having a cyclic alkyl group, (meth)acrylates having an aromatic group, (meth)acrylates having a hydroxy group, (meth)acrylates having an alkoxy group, (meth)acrylates having a cyclic ether group, and (meth)acrylates having a lactone-modified hydroxy group.

[0049] Examples of the (meth)acrylate having a chain alkyl group include (meth)acrylates having a straight-chain alkyl group and (meth)acrylates having a branched-chain alkyl group.

[0050] The (meth)acrylate having a linear alkyl group is preferably a (meth)acrylate having a linear alkyl group with a carbon number of 1 to 20, more preferably a (meth)acrylate having a linear alkyl group with a carbon number of 1 to 10, and even more preferably a (meth)acrylate having a linear alkyl group with a carbon number of 1 to 5. Examples of the (meth)acrylate having a linear alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, n-decyl (meth)acrylate, n-lauryl (meth)acrylate, and n-stearyl (meth)acrylate.

[0051] The (meth)acrylate having a branched chain alkyl group is preferably a (meth)acrylate having a branched chain alkyl group in which the carbon number of the branched chain alkyl group is 3 to 20, and more preferably a (meth)acrylate having a branched chain alkyl group in which the carbon number of the branched chain alkyl group is 3 to 10. Examples of the (meth)acrylate having a branched chain alkyl group include isopropyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate, and isodecyl (meth)acrylate.

[0052] The (meth)acrylate having a cyclic alkyl group is preferably a (meth)acrylate having a cyclic alkyl group having 6 to 12 carbon atoms in the cyclic alkyl group. Examples of the cyclic alkyl group include a cyclic alkyl group having a monocyclic structure (e.g., a cycloalkyl group) and a cyclic alkyl group having a bridged ring structure (e.g., an adamantyl group, a norbornyl group, or an isobornyl group). Specific examples of the (meth)acrylate having a cyclic alkyl group having a monocyclic structure include cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, and cyclododecyl (meth)acrylate. Specific examples of the (meth)acrylate having a cyclic alkyl group having a bridged ring structure include isobornyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentanyloxyethyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, and 2-ethyl-2-adamantyl (meth)acrylate.

[0053] The (meth)acrylate having an aromatic group is preferably a (meth)acrylate having an aromatic group with 6 to 12 carbon atoms, and more preferably a (meth)acrylate having an aromatic group with 6 to 9 carbon atoms. Examples of the aromatic group include an aryl group, and the aromatic group may also have a chain moiety such as an alkylaryl group, an aralkyl group, or an aryloxyalkyl group. Specific examples of the (meth)acrylate having an aromatic group include benzyl (meth)acrylate, phenyl (meth)acrylate, and phenoxyethyl (meth)acrylate.

[0054] The (meth)acrylate having a hydroxy group is preferably a hydroxyalkyl (meth)acrylate. The hydroxyalkyl group of the hydroxyalkyl (meth)acrylate preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms. The hydroxyalkyl group may be linear or branched, and preferably has one hydroxy group. Specific examples of the (meth)acrylate having a hydroxy group include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, and 12-hydroxylauryl (meth)acrylate. Among these, (meth)acrylates having a hydroxyalkyl group having 1 to 5 carbon atoms are more preferred.

[0055] Examples of the (meth)acrylate having an alkoxy group include methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate.

[0056] Examples of the (meth)acrylate having a cyclic ether group include glycidyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, tetrahydrofuranylmethoxyethyl (meth)acrylate, tetrahydrofuranylmethoxypropyl (meth)acrylate, tetrahydrofuranylmethoxyisopropyl (meth)acrylate, (3-ethyloxetan-3-yl)methyl (meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl (meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate, 2-[(2-tetrahydropyranyl)oxy]ethyl (meth)acrylate, and (1,3-dioxolan-4-yl)methyl (meth)acrylate.

[0057] Examples of the (meth)acrylate having a lactone-modified hydroxy group include those obtained by adding a lactone to the (meth)acrylate having a hydroxy group, and those obtained by adding caprolactone are preferred. The amount of lactone added is preferably 1 mol to 10 mol, and more preferably 1 mol to 5 mol. Examples of the (meth)acrylate having a lactone-modified hydroxy group include a 1 mol adduct of 2-hydroxyethyl (meth)acrylate with caprolactone, a 2 mol adduct of 2-hydroxyethyl (meth)acrylate with caprolactone, a 3 mol adduct of 2-hydroxyethyl (meth)acrylate with caprolactone, a 4 mol adduct of 2-hydroxyethyl (meth)acrylate with caprolactone, a 5 mol adduct of 2-hydroxyethyl (meth)acrylate with caprolactone, and a 10 mol adduct of 2-hydroxyethyl (meth)acrylate with caprolactone.

[0058] Specific examples of the vinyl monomer capable of forming the structural unit derived from a vinyl monomer other than the (meth)acrylic monomer include α-olefins, vinyl monomers containing a heterocycle, vinylamides, vinyl carboxylates, dienes, etc. These vinyl monomers may have a hydroxy group or an epoxy group.

[0059] Examples of α-olefins include 1-hexene, 1-octene, and 1-decene. Examples of vinyl monomers containing a heterocycle include 2-vinylthiophene. Examples of vinylamides include N-vinylformamide and N-vinylacetamide. Examples of vinyl carboxylates include vinyl acetate, vinyl pivalate, and vinyl benzoate. Examples of dienes include butadiene, isoprene, 4-methyl-1,4-hexadiene, and 7-methyl-1,6-octadiene.

[0060] It is preferred that the A block does not substantially contain the structural unit (b-1) having a nitrogen-containing heterocyclic group, which will be described later. That is, the content of the structural unit (b-1) having a nitrogen-containing heterocyclic group is preferably 3% by mass or less, more preferably 1% by mass or less, and even more preferably 0.1% by mass or less, based on 100% by mass of the A block.

[0061] When two or more types of structural units are contained in the A block, the various structural units contained in the A block may be contained in the A block in any form such as random copolymerization or block copolymerization, and from the viewpoint of uniformity, it is preferable that they are contained in the A block in the form of random copolymerization. For example, the A block may be formed from a copolymer of structural units consisting of the a1 block and structural units consisting of the a2 block.

[0062] (Block B) The block B contains a structural unit (b-1) having a nitrogen-containing heterocyclic group and a structural unit (b-2) having an aliphatic hydrocarbon group.

[0063] (Structural Unit (b-1)) The B block contains a structural unit (b-1) having a nitrogen-containing heterocyclic group. By containing the structural unit (b-1) having a nitrogen-containing heterocyclic group, the B block has high affinity with the yellow azo pigment, which is a colorant. The structural unit (b-1) may be of only one type, or may have two or more types.

[0064] Examples of the nitrogen-containing heterocyclic group include aromatic heterocyclic groups such as a 4-pyridyl group, a 1-imidazole group, a 2-pyridyl group, and a 9-carbazole group; and non-aromatic heterocyclic groups such as a 1-piperidyl group, a 1-pyrrolidyl group, a 4-morpholino group, and a lactam group, with a lactam group being preferred.

[0065] The lactam group refers to a group obtained by removing a hydrogen atom or an alkyl group bonded to a nitrogen atom of a lactam compound, and may be substituted with a carboxyl group, a sulfonic acid group, or an ester or salt thereof, an amino group, a hydroxyl group, an alkyl group, or the like.

[0066] Examples of the lactam compound include caprolactam; N-alkylcaprolactams such as N-ethylcaprolactam, N-isopropylcaprolactam, N-isobutylcaprolactam, N-normal propylcaprolactam, N-normal butylcaprolactam, and N-cyclohexylcaprolactam; pyrrolidones such as 2-pyrrolidone, N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-isobutyl-2-pyrrolidone, N-normal propyl-2-pyrrolidone, N-normal butyl-2-pyrrolidone, and N-cyclohexyl-2-pyrrolidone; and piperidones such as 2-piperidone, N-methyl-2-piperidone, N-ethyl-2-piperidone, and N-isopropyl-2-piperidone.

[0067] The structural unit (b-1) is preferably a structural unit represented by the following formula (4).

[0068] [In formula (4), R 41 , R 42 , R 43 and R 44 are the same or different and represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms which may have a substituent; m4 represents an integer of 0 to 4; and n4 represents an integer of 1 to 3.

[0069] The R 41 ~R 44The number of carbon atoms in the alkyl group in R is preferably 1 to 6, more preferably 1 to 4. The alkyl group is preferably a methyl group or an ethyl group, more preferably a methyl group. 41 ~R 44 The substituent in is not particularly limited, but examples thereof include a carboxy group, a sulfonic acid group, and esters and salts thereof; an amino group; and a hydroxy group.

[0070] The R 41 is preferably a hydrogen atom or a methyl group, more preferably a hydrogen atom. 42 ~R 44 is preferably a hydrogen atom. The m4 is preferably an integer of 0 to 2, more preferably an integer of 0 to 1, and even more preferably 0. The n4 is preferably 1 or 2, and more preferably 1.

[0071] Examples of vinyl monomers that form the structural unit represented by formula (4) include vinyl monomers having a 5-membered cyclic lactam group, such as N-vinylpyrrolidone, N-vinyl-5-methylpyrrolidone, N-vinyl-5-ethylpyrrolidone, N-vinyl-5-propylpyrrolidone, N-vinyl-5-butylpyrrolidone, and 1-(2-propenyl)-2-pyrrolidone; vinyl monomers having a 6-membered cyclic lactam group, such as N-vinylpiperidone; and vinyl monomers having a 7-membered cyclic lactam group, such as N-vinylcaprolactam. One or more vinyl monomers that form the structural unit represented by formula (4) can be used. Among these, vinyl monomers having a 5-membered cyclic lactam group are preferred, and N-vinylpyrrolidone is more preferred.

[0072] The content of the structural unit (b-1) in 100% by mass of the B block is preferably 51% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, and is preferably 99% by mass or less, more preferably 95% by mass or less, and even more preferably 90% by mass or less. When the content of the structural unit (b-1) is within the above range, good adsorption to the yellow azo pigment is achieved.

[0073] (Structural Unit (b-2)) The B block contains a structural unit (b-2) having an aliphatic hydrocarbon group. By containing the structural unit (b-2) having an aliphatic hydrocarbon group, adsorption to the yellow azo pigment becomes better. The structural unit (b-2) may be of only one type, or may have two or more types.

[0074] In the structural unit (b-2) having an aliphatic hydrocarbon group, the aliphatic hydrocarbon group is introduced into a side chain portion, and the position is preferably at a position two atoms or more away from the main chain. In this specification, "the hydrocarbon group is at a position two atoms or more away from the main chain" refers to a state in which the position of the carbon atom on the main chain of the polymer to which the side chain is bonded is taken as 0 (zero), and the hydrocarbon group is bonded to a position on the side chain that is the second atom or later from that position. The atom on the side chain may be an atom other than carbon or a substituent.

[0075] Examples of the aliphatic hydrocarbon group include a linear alkyl group, a branched alkyl group, an alkyl group having a monocyclic structure, and an alkyl group having a polycyclic structure, and preferred are linear alkyl groups and alkyl groups having a monocyclic structure.

[0076] The linear alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, and even more preferably 1 to 5 carbon atoms. Examples of the linear alkyl group include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-hexyl group, an n-octyl group, an n-nonyl group, an n-decyl group, and an n-lauryl group. The branched alkyl group preferably has 3 to 20 carbon atoms, more preferably 3 to 10 carbon atoms, and even more preferably 3 to 5 carbon atoms. Examples of the branched alkyl group include an isopropyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a 2-ethylhexyl group, a neopentyl group, and an isooctyl group.

[0077] The number of carbon atoms in the alkyl group having a monocyclic structure is preferably 4 to 18, more preferably 6 to 12, and even more preferably 6 to 10. Examples of the alkyl group having a monocyclic structure include a cyclohexyl group, a methylcyclohexyl group, a cyclododecyl group, a 3,3,5-trimethylcyclohexyl group, and a 4-tert-butylcyclohexyl group. The number of carbon atoms in the alkyl group having a polycyclic structure is preferably 5 to 20, more preferably 7 to 18, and even more preferably 9 to 15. Examples of the alkyl group having a polycyclic structure include a bornyl group, an isobornyl group, a 1-adamantyl group, a 2-adamantyl group, a 2-methyl-2-adamantyl group, a 2-ethyl-2-adamantyl group, a norbornyl group, a dicyclopentanyl group, and a dicyclopentenyl group.

[0078] The structural unit (b-2) is preferably a structural unit represented by formula (5).

[0079] [In formula (5), R 51 represents an aliphatic hydrocarbon group. 5 represents O or NH. 52 represents a hydrogen atom or a methyl group.

[0080] The R 51 Examples of the aliphatic hydrocarbon group represented by R include a linear alkyl group, a branched alkyl group, an alkyl group having a monocyclic structure, and an alkyl group having a polycyclic structure, and the linear alkyl group or the alkyl group having a monocyclic structure is preferred. 51 The number of carbon atoms in the linear alkyl group represented by the formula (I) is preferably 1 to 20, more preferably 1 to 10, and even more preferably 1 to 5. 51 The number of carbon atoms in the branched alkyl group represented by the formula (I) is preferably 3 to 20, more preferably 3 to 10, and even more preferably 3 to 5. 51 The number of carbon atoms in the alkyl group having a monocyclic structure represented by the formula (I) is preferably 4 to 18, more preferably 6 to 12, and even more preferably 6 to 10. 51 The number of carbon atoms in the alkyl group having a polycyclic structure represented by the formula (I) is preferably 5 to 20, more preferably 7 to 18, and even more preferably 9 to 15. 5 is preferably O.52 is preferably a hydrogen atom.

[0081] Examples of vinyl monomers that form the structural unit represented by formula (5) include (meth)acrylates having a linear alkyl group, (meth)acrylates having a branched alkyl group, (meth)acrylates having a monocyclic alkyl group, (meth)acrylates having a polycyclic alkyl group, (meth)acrylamides having a linear alkyl group, (meth)acrylamides having a branched alkyl group, (meth)acrylamides having a monocyclic alkyl group, (meth)acrylamides having a polycyclic alkyl group, etc. Among these, one or more (meth)acrylates selected from the group consisting of (meth)acrylates having a linear alkyl group and (meth)acrylates having a monocyclic alkyl group are preferred.

[0082] Examples of the (meth)acrylate having a linear alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, n-decyl (meth)acrylate, n-lauryl (meth)acrylate, and n-stearyl (meth)acrylate.

[0083] Examples of the (meth)acrylate having a branched alkyl group include isopropyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate, and isodecyl (meth)acrylate.

[0084] Examples of the (meth)acrylate having an alkyl group with a monocyclic structure include cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, cyclododecyl (meth)acrylate, 3,3,5-(trimethyl)cyclohexyl (meth)acrylate, and 4-(tert-butyl)cyclohexyl (meth)acrylate.

[0085] Examples of the (meth)acrylate having an alkyl group with a polycyclic structure include bornyl (meth)acrylate, isobornyl (meth)acrylate, 1-adamantyl (meth)acrylate, 2-adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, 2-ethyl-2-adamantyl (meth)acrylate, norbornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentanyloxyethyl (meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate.

[0086] The content of the structural unit (b-2) in 100% by mass of the B block is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, and is preferably 49% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less. If the content of the structural unit (b-2) is within the above range, the dispersibility of the yellow azo pigment can be further improved.

[0087] The total content of the structural units (b-1) and (b-2) in 100% by mass of the B block is preferably 56% by mass or more, more preferably 60% by mass or more, even more preferably 65% ​​by mass or more, and particularly preferably 90% by mass or more. If the total content of the structural units (b-1) and (b-2) is within the above range, the dispersibility of the yellow azo pigment can be further improved.

[0088] The mass ratio (b-1 / b-2) of the structural unit (b-1) to the structural unit (b-2) in the B block is preferably 1.04 or more, more preferably 1.1 or more, and even more preferably 1.2 or more, and is preferably 99 or less, more preferably 19 or less, and even more preferably 9 or less. When the mass ratio (b-1 / b-2) is within the above range, the dispersibility of the yellow azo pigment can be further improved.

[0089] (Other Structural Units) The B block may contain structural units other than the structural unit (b-1) and the structural unit (b-2) to the extent that the effects of the present invention are not impaired. Specific examples of vinyl monomers capable of forming other structural units in the B block include the same monomers as those exemplified as specific examples of monomers capable of forming structural units in the A block and other structural units.

[0090] The content of the structural unit (a-1) in the B block is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less, and it is particularly preferred that the B block does not contain the structural unit (a-1).

[0091] The content of the structural unit (a-2) in the B block is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less, and it is particularly preferred that the B block does not contain the structural unit (a-2).

[0092] When two or more types of structural units are contained in the B block, the various structural units contained in the B block may be contained in the B block in any form, such as random copolymerization or block copolymerization, and from the viewpoint of uniformity, they are preferably contained in the B block in the form of random copolymerization. For example, the B block may be formed from a copolymer of structural units consisting of the b1 block and structural units consisting of the b2 block.

[0093] (Block Copolymer) The structure of the block copolymer is preferably a linear block copolymer. The linear block copolymer may have any structure (arrangement). However, from the viewpoint of the physical properties of the linear block copolymer or the physical properties of the composition, when the A block is represented as A and the B block is represented as B, the structure (arrangement) of the linear block copolymer is (A-B) m Type, (A-B) m -A type and (BA) mA-B type diblock copolymers are preferred, having at least one structure selected from the group consisting of A-B type diblock copolymers (m is an integer of 1 or more, for example, an integer of 1 to 3). Among these, A-B type diblock copolymers are preferred from the viewpoints of handleability during processing and the physical properties of the composition. By forming an A-B type diblock copolymer, the structural unit (a-1) and the structural unit (a-2) are localized in the A block, and the structural unit (b-1) is localized in the B block, which is thought to enable efficient and favorable interaction with the yellow azo pigment (colorant) and the aqueous dispersion medium. The block copolymer may have blocks other than the A block and the B block.

[0094] The content of the A block, based on 100% by mass of the entire block copolymer, is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and is preferably 99% by mass or less, more preferably 95% by mass or less, and even more preferably 90% by mass or less. The content of the B block, based on 100% by mass of the entire block copolymer, is preferably 1% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, and is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less. By adjusting the contents of the A block and B block within the above ranges, the dispersing performance as a dispersant is further improved.

[0095] The mass ratio of the A block to the B block (A block / B block) in the block copolymer is preferably 50 / 50 or more, more preferably 60 / 40 or more, and even more preferably 70 / 30 or more, and is preferably 99 / 1 or less, more preferably 95 / 5 or less, and even more preferably 90 / 10 or less. If the mass ratio of the A block to the B block is within the above range, the dispersing performance as a dispersant is further improved.

[0096] The content of the structural unit (a-1) is preferably 5% by mass or more, more preferably 8% by mass or more, and even more preferably 10% by mass or more, based on 100% by mass of the entire block copolymer, and is preferably 63% by mass or less, more preferably 54% by mass or less, and even more preferably 45% by mass or less.

[0097] The content of the structural unit (a-2) is preferably 5% by mass or more, more preferably 7% by mass or more, and even more preferably 10% by mass or more, based on 100% by mass of the entire block copolymer, and is preferably 34% by mass or less, more preferably 31% by mass or less, and even more preferably 28% by mass or less.

[0098] The content of the structural unit (b-1) is preferably 5% by mass or more, more preferably 7% by mass or more, and even more preferably 10% by mass or more, based on 100% by mass of the entire block copolymer, and is preferably 49.5% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less.

[0099] The content of the structural unit (b-2) is preferably 0.1% by mass or more, more preferably 1% by mass or more, and even more preferably 3% by mass or more, based on 100% by mass of the entire block copolymer; and is preferably 24.5% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less.

[0100] The acid value (acid value before neutralization) of the block copolymer is preferably 50 mgKOH / g or more, more preferably 60 mgKOH / g or more, and even more preferably 70 mgKOH / g or more, and is preferably 200 mgKOH / g or less, more preferably 180 mgKOH / g or less, and even more preferably 160 mgKOH / g or less. When the acid value of the block copolymer is within the above range, the viscosity stability of the colored composition becomes good.

[0101] The molecular weight of the block copolymer is measured by gel permeation chromatography (hereinafter referred to as "GPC"). The weight average molecular weight (Mw) of the block copolymer is preferably 5,000 or more, more preferably 8,000 or more, even more preferably 10,000 or more, and is preferably 40,000 or less, more preferably 30,000 or less, even more preferably 20,000 or less. If the Mw is within the above range, the dispersing performance when used as a dispersant will be better.

[0102] The molecular weight distribution of the block copolymer is preferably 2.5 or less, more preferably 2.0 or less, and even more preferably 1.8 or less. In this specification, the molecular weight distribution is calculated by (weight average molecular weight (Mw) of the block copolymer) / (number average molecular weight (Mn) of the block copolymer). The smaller the value, the narrower the molecular weight distribution, resulting in a copolymer with a uniform molecular weight. When the value is 1.0, the molecular weight distribution is narrowest. In other words, the lower limit of the molecular weight distribution is 1.0. When the molecular weight distribution of the block copolymer exceeds 2.5, it will contain both low and high molecular weight copolymers.

[0103] (Method for Producing Block Copolymer) Examples of methods for producing a block copolymer include a method in which an A block is first produced by a polymerization reaction of a vinyl monomer and then a monomer for a B block is polymerized onto the A block; a method in which a B block is first produced and then a monomer for an A block is polymerized onto the B block; and a method in which the A block and the B block are produced separately and then the A block and the B block are coupled together.

[0104] Although the polymerization method is not particularly limited, living polymerization is preferred. That is, the block copolymer is preferably one polymerized by living polymerization. Among the four elementary reactions in chain polymerization, namely, initiation reaction, propagation reaction, termination reaction, and chain transfer reaction, living polymerization is substantially free of side reactions such as termination reaction and chain transfer reaction, and the vinyl monomer reacts and the polymer chain grows without deactivating the reactive site (polymerization growth end). Therefore, it is easy to produce a copolymer with a narrow molecular weight distribution and a uniform composition. Living polymerization includes living radical polymerization, living anionic polymerization, living cationic polymerization, etc. Among these, living radical polymerization is preferred from the viewpoint of simplicity of polymerization. Furthermore, living radical polymerization is preferred because it maintains the simplicity and versatility of conventional radical polymerization while allowing precise control of molecular weight distribution and facilitating the production of polymers with a uniform composition.

[0105] Living radical polymerization, depending on the method for stabilizing the polymer growing end, includes a method using a compound capable of generating a nitroxide radical (nitroxide method; NMP method); a method using a metal complex such as copper or ruthenium to polymerize a halogenated compound as a polymerization initiator compound in a living manner from the polymerization initiator compound (ATRP method); a method using a dithiocarboxylic acid ester or a xanthate compound (RAFT method); a method using an organic tellurium compound (TERP method); a method using an organic iodine compound (ITP method); and a method using an iodine compound as a polymerization initiator compound and an organic compound such as a phosphorus compound, a nitrogen compound, an oxygen compound, or a hydrocarbon as a catalyst (reversible transfer catalyst polymerization; RTCP method, reversible catalyst-mediated polymerization; RCMP method). Among these methods, the TERP method is preferred from the viewpoints of the variety of monomers that can be used, molecular weight control in the polymer region, uniform composition, and coloration.

[0106] The TERP method is a method of polymerizing a radically polymerizable compound (vinyl monomer) using an organic tellurium compound as a chain transfer agent, and is a method described in, for example, WO 2004 / 14848, WO 2004 / 14962, WO 2004 / 072126, WO 2004 / 096870, and WO 2020 / 116144.

[0107] Specific polymerization methods of the TERP method include the following (a) to (d): (a) a method of polymerizing a vinyl monomer using an organotellurium compound represented by formula (T1). (b) a method of polymerizing a vinyl monomer using a mixture of an organotellurium compound represented by formula (T1) and an azo-based polymerization initiator. (c) a method of polymerizing a vinyl monomer using a mixture of an organotellurium compound represented by formula (T1) and an organic ditelluride compound represented by formula (T2). (d) a method of polymerizing a vinyl monomer using a mixture of an organotellurium compound represented by formula (T1), an azo-based polymerization initiator, and an organic ditelluride compound represented by formula (T2).

[0108] [In formula (T1), R arepresents an alkyl group having 1 to 8 carbon atoms, an aryl group, or an aromatic heterocyclic group. b and R c R each independently represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. d represents an alkyl group having 1 to 8 carbon atoms, an aryl group, a substituted aryl group, an aromatic heterocyclic group, an alkoxy group, an acyl group, an amido group, an oxycarbonyl group, a cyano group, an allyl group, or a propargyl group. a represents an alkyl group having 1 to 8 carbon atoms, an aryl group, or an aromatic heterocyclic group.]

[0109] Specific examples of the organic tellurium compound represented by formula (T1) include ethyl 2-methyl-2-n-butyltellanyl-propionate, ethyl 2-n-butyltellanyl-propionate, (2-hydroxyethyl) 2-methyl-methyltellanyl-propionate, and the organic tellurium compounds described in WO 2004 / 14848, WO 2004 / 14962, WO 2004 / 072126, WO 2004 / 096870, and WO 2020 / 116144.

[0110] Specific examples of the organic ditelluride compound represented by formula (T2) include dimethyl ditelluride, dibutyl ditelluride, etc. The azo polymerization initiator can be any azo polymerization initiator used in ordinary radical polymerization without any particular limitation, and examples thereof include 2,2'-azobis(isobutyronitrile) (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile) (ADVN), 1,1'-azobis(1-cyclohexanecarbonitrile) (ACHN), dimethyl-2,2'-azobisisobutyrate (MAIB), 4,4'-azobis(4-cyanovaleric acid) (ACVA), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) (V-70), 2,2'-azobis(N-butyl-2-methylpropionamide) (VAm-110), etc.

[0111] In the polymerization step, a vinyl monomer and an organotellurium compound of formula (T1) are mixed in a vessel purged with an inert gas, and for the purposes of promoting the reaction and controlling the molecular weight and molecular weight distribution depending on the type of vinyl monomer, an azo polymerization initiator and / or an organic ditelluride compound of formula (T2) is further mixed. Examples of the inert gas include nitrogen, argon, and helium. Argon and nitrogen are preferred. The amounts of the vinyl monomer used in steps (a), (b), (c), and (d) can be adjusted appropriately depending on the physical properties of the desired copolymer.

[0112] The polymerization reaction can be carried out without a solvent, but it can also be carried out by stirring the mixture using an aprotic or protic solvent commonly used in radical polymerization. Examples of aprotic solvents that can be used include anisole, benzene, toluene, propylene glycol monomethyl ether acetate, ethyl acetate, and tetrahydrofuran (THF). Examples of protic solvents include water, methanol, and 1-methoxy-2-propanol. Solvents can be used alone or in combination. The amount of solvent used can be adjusted appropriately; for example, 0.01 ml to 50 ml per 1 g of vinyl monomer is preferred. In addition to the solvent, a surfactant and / or dispersant can also be used in the polymerization reaction. The reaction temperature and reaction time can be adjusted appropriately depending on the molecular weight or molecular weight distribution of the resulting copolymer; however, the reaction is typically carried out at 0°C to 150°C with stirring for 1 minute to 100 hours. The pressure is typically atmospheric, but increased or decreased pressure may also be used. The polymerization reaction may also be carried out under light irradiation. After the polymerization reaction is completed, the target copolymer can be separated from the resulting reaction mixture by ordinary separation and purification means, such as by removing the solvent used and the remaining vinyl monomer.

[0113] The growing end of the copolymer obtained by the polymerization reaction is -TeR derived from the tellurium compound. a (In the formula, R ais the same as above), and is deactivated by handling in air after the polymerization reaction is completed, but tellurium atoms may remain. A copolymer with tellurium atoms remaining at the end is colored and has poor thermal stability, so it is preferable to remove the tellurium atoms. Methods for removing tellurium atoms include a radical reduction method; a method of adsorption with activated carbon or the like; a method of adsorbing metal with an ion exchange resin or the like, and these methods can also be used in combination. The other end of the copolymer obtained by the polymerization reaction (the end opposite to the growing end) is formed from a -CR derived from the tellurium compound. b R c R d (In the formula, R b , R c and R d is R in formula (T1) b , R c and R d Therefore, the copolymer obtained by the TERP method does not have a substituent containing a sulfur atom at the terminal.

[0114] [Coloring composition] The coloring composition of the present invention contains a yellow azo pigment, a dispersant, and an aqueous dispersion medium. Because the coloring composition of the present invention has high dispersibility of colorants, it can be used for inkjet inks, printing inks, inks for writing instruments, paints, etc.

[0115] [Yellow Azo Pigment] The yellow azo pigment is a general term for yellow pigments having at least one azo structure or azomethine structure in the molecule. The azo structure is a structure in which two nitrogen atoms are connected by a double bond. The azomethine structure is a structure in which a hydrocarbon group is bonded to a nitrogen atom. The yellow azo pigment has an azo structure or azomethine structure in the molecule, and has high affinity with the structural unit (b-1) having a nitrogen-containing heterocyclic group contained in the dispersant. Therefore, the coloring composition has excellent dispersion stability of the yellow azo pigment. The yellow azo pigment may be used alone or in combination of two or more types.

[0116] Examples of the yellow azo pigment include azo lake pigments and insoluble azo pigments.

[0117] Examples of the azo lake pigment include C.I. Pigment Yellow 133, 168, and 169. In this specification, "C.I." is an abbreviation for Color Index.

[0118] Examples of the insoluble azo pigments include azomethine metal complex pigments, acetoacetate arylide pigments, and pyrazolone pigments.

[0119] Examples of the azomethine metal complex pigment include metal complex pigments containing divalent or trivalent metal ions selected from the group consisting of Cu, Fe, Co, Ni, and Zn, with an azomethine compound as a ligand, such as C.I. Pigment Yellow 117, 129, 150, and 153. Examples of the metal ions include Cu, 2+ , Fe 2+ , Fe 3+ , Co 2+ , Co 3+ , Ni 2+ , Zn 2+ etc.

[0120] The azomethine metal complex pigment is preferably at least one selected from the group consisting of C. I. Pigment Yellow 117, C. I. Pigment Yellow 129, C. I. Pigment Yellow 150, and C. I. Pigment Yellow 153.

[0121] The azomethine metal complex pigment is preferably a metal complex pigment having a cyclic azomethine compound represented by formula (10) or a tautomer thereof as a ligand. A tautomer is a compound having a structure that can be formed by the migration of one hydrogen atom in the molecule.

[0122] In formula (10), X represents a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms or a group having a 5- or 6-membered nitrogen-containing heterocycle. 91 and R 92 each independently represents a hydrogen atom, a monovalent hydrocarbon group having 1 to 5 carbon atoms, or a sulfonic acid group (—SO3H).

[0123] Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms represented by X include a phenyl group, a naphthyl group, a benzyl group, and a phenoxyethyl group. Examples of the group having a 5- or 6-membered nitrogen-containing heterocycle represented by X include a pyrrolidyl group, a pyrrolyl group, a piperidyl group, a pyridyl group, an imidazole group, a pyrazole group, an oxazole group, a morpholino group, a pyrimidyl group, and a pyrazyl group. 91 and R 92 Examples of the monovalent hydrocarbon group having 1 to 5 carbon atoms represented by the formula (I) include a methyl group, an ethyl group, a propyl group, a butyl group, and a pentyl group.

[0124] The azomethine metal complex pigment is preferably a metal complex pigment having a structure represented by formula (11) or a tautomer thereof.

[0125] In formula (11), M represents a divalent or trivalent metal ion selected from Fe, Co, Ni, and Zn. 91 ~R 94 are each independently a hydrogen atom, a monovalent hydrocarbon group having 1 to 5 carbon atoms, or a sulfonic acid group (—SO ３ H).

[0126] The R 91 ~R 94 Examples of the monovalent hydrocarbon group having 1 to 5 carbon atoms represented by the formula (I) include a methyl group, an ethyl group, a propyl group, a butyl group, and a pentyl group. 2+ , Fe 3+ 2 / 3 , Co 2+ , Co 3+ 2 / 3 , Ni 2+ and Zn 2+ More preferred are divalent or trivalent metal ions selected from the group consisting of:

[0127] Among the azomethine metal complex pigments, the azobarbituric acid nickel complex pigment represented by formula (12), i.e., Pigment Yellow 150, is more preferred from the viewpoints of storage stability and ease of maintenance.

[0128]

[0129] The acetoacetate arylide pigment has a structure derived from acetoacetate arylide in the molecule (Formula 13). The acetoacetate arylide pigment also includes a condensed azo pigment synthesized by condensing the acetoacetate arylide pigment.

[0130] [In formula (13), A represents a phenyl group which may have a substituent, or a benzimidazolone ring. * represents a bond.]

[0131] Examples of the acetoacetate arylide pigments include C.I. Pigment Yellow 1, 2, 3, 5, 6, 49, 63, 65, 73, 74, 75, 87, 90, 97, 98, 106, 111, 114, 116, 121, 124, 126, 127, 130, 136, 152, 165, 167, 174, and 176 Hansa pigments, C.I. Pigment Yellow 120, 151, 154, 156, 175, 181, and 194 benzimidazolone pigments, and monoazo pigments such as dicyclobenzidine pigments, C.I. Pigment Yellow 12, 13, 14, 17, 55, and 83, and C.I. Examples of suitable pigments include benzimidazolone pigments such as C.I. Pigment Yellow 180, disazo pigments such as C.I. Pigment Yellow 81, 113, 170, 171, 172, 188, and 214, and condensed azo pigments such as C.I. Pigment Yellow 93, 94, 95, 128, 155, and 166.

[0132] The pyrazolone pigments are synthesized using pyrazolones as raw materials and have a structure derived from pyrazolones in the molecule (formula (14)). Examples of the pyrazolone pigments include C.I. Pigment Yellow 10 and 60.

[0133] [In formula (14), R represents a methyl group or an ethoxycarbonyl group. * represents a bond.]

[0134] The yellow azo pigment is preferably an insoluble azo pigment. The effects of the present invention are more pronounced when the yellow azo pigment is an insoluble azo pigment that is insoluble in water. Among the insoluble azo pigments, at least one selected from the group consisting of azomethine metal complex pigments and acetoacetate arylide pigments is more preferred. These yellow azo pigments have a specific structure, which increases their affinity with the block copolymer and further enhances their dispersion stability. Among these, azomethine metal complex pigments are particularly preferred because they are yellow pigments with high weather resistance.

[0135] The content of the yellow azo pigment in the coloring composition may be adjusted appropriately depending on the application, and is preferably 2% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, and is preferably 80% by mass or less, more preferably 60% by mass or less, and even more preferably 40% by mass or less, based on the total solid content of the coloring composition. If the content of the yellow azo pigment is within the above range, when the coloring composition is used in an ink, a sufficient color density can be imparted to the recording medium. Here, the solid content refers to components other than the dispersion medium, which will be described later.

[0136] The coloring composition of the present invention may contain other yellow colorants other than the yellow azo pigment as long as the effects of the present invention are not impaired. Examples of other yellow colorants include yellow disperse dyes such as C.I. Disperse Yellow 9, 23, 33, 42, 49, 54, 58, 60, 64, 66, 71, 76, 79, 83, 86, 90, 93, 99, 114, 116, 119, 122, 126, 149, 160, 163, 165, 180, 183, 186, 198, 200, 211, 224, 226, 227, 231, and 237.

[0137] When the coloring composition contains the other yellow colorant, the content of the other yellow colorant is preferably 1 part by mass to 50 parts by mass with respect to 100 parts by mass of the yellow azo pigment.

[0138] The yellow azo pigment and other yellow colorants may contain a dye derivative (synergist) as a dispersing aid. This further improves the dispersibility of the colorant. The dye derivative is a compound in which an organic dye residue is bonded to an acidic group such as a sulfonic acid group, a carboxyl group, or a phosphate group; or a neutral group such as a phenyl group or a phthalimidoalkyl group. The organic dye residue is a substituent having an organic dye structure (dye skeleton), and is preferably the same or similar dye skeleton as the organic colorant constituting the coloring composition, or the same or similar dye skeleton as the compound serving as the raw material for the organic colorant. Examples of the dye skeleton include azomethine dye derivatives, isoindolinone dye derivatives, isoindoline dye derivatives, benzimidazolone dye derivatives, azo dye skeletons, and anthraquinone dye skeletons. The amount of dye derivative used is not particularly limited, but is preferably 0.5 to 5 parts by weight per 100 parts by weight of the colorant.

[0139] [Dispersant] The colored composition contains the neutralized product of the block copolymer as a dispersant. By using the neutralized product of the block copolymer as a dispersant, a colored composition having excellent dispersion stability can be obtained.

[0140] In the neutralized product of the block copolymer used as the dispersant, more than 50 mol % of the 100 mol % of the acidic groups possessed by the structural unit (a-2) have been neutralized. By neutralizing more than 50 mol % of the acidic groups possessed by the structural unit (a-2), affinity with the aqueous dispersion medium is increased.

[0141] In the neutralized product of the block copolymer, the proportion of neutralized acidic groups out of 100 mol % of the acidic groups in the structural unit (a-2) is greater than 50 mol %, preferably 55 mol % or greater. Neutralizing more than 50 mol % of the acidic groups in the structural unit (a-2) allows for a colored composition with excellent dispersion stability to be obtained. The neutralized product of the block copolymer may be a fully neutralized product in which all of the acidic groups in the structural unit (a-2) are neutralized, or a partially neutralized product in which some of the acidic groups in the structural unit (a-2) are neutralized. When the dispersant is a partially neutralized product of the block copolymer, the proportion of neutralized acidic groups out of 100 mol % of the acidic groups in the structural unit (a-2) is preferably 95 mol % or less, more preferably 80 mol % or less. By leaving some of the acidic groups in the structural unit (a-2) unneutralized, the dispersion stability of the colorant in the colored composition tends to be further improved.

[0142] The component that neutralizes the acidic group in the structural unit (a-2) includes at least one selected from the group consisting of alkali metals, organic amines, and ammonia, and preferably at least one selected from the group consisting of alkali metals and organic amines. Examples of the alkali metal include lithium, sodium, and potassium. Examples of the organic amine include alkanolamines such as monoethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, monopropanolamine, dipropanolamine, tripropanolamine, N-methylethanolamine, and 2-(dimethylamino)ethanol; and alkylamines such as monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, and triethylamine.

[0143] The content of the dispersant in the coloring composition is preferably 5 parts by mass to 200 parts by mass, more preferably 15 parts by mass to 100 parts by mass, and even more preferably 30 parts by mass to 80 parts by mass, relative to 100 parts by mass of the yellow azo pigment.

[0144] [Dispersion Medium] The coloring composition contains an aqueous dispersion medium as a dispersion medium. Examples of the aqueous dispersion medium include water and aqueous organic solvents (organic solvents miscible with water). Examples of water include pure water and ion-exchanged water (deionized water). Examples of aqueous organic solvents include alcohols such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, 1-methoxy-2-propanol, and 1-butoxy-2-propanol; polyhydric alcohols such as ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, diethylene glycol, polyethylene glycol, polypropylene glycol, and glycerin; ethers such as tetrahydrofuran, dioxane, ethylene glycol methyl ether, ethylene glycol ethyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, triethylene glycol, monomethyl ether, and monoethyl ether; ketones such as acetone, methyl ethyl ketone, and isobutyl ketone; and amides such as dimethylformaldehyde and dimethylacetamide. The aqueous dispersion medium may be used alone or in combination of two or more kinds.

[0145] The content of the aqueous dispersion medium in the coloring composition is not particularly limited and can be adjusted appropriately. The upper limit of the content of the aqueous dispersion medium in the coloring composition is usually 99% by mass. The lower limit of the content of the aqueous dispersion medium in the coloring composition is usually 60% by mass, preferably 80% by mass, taking into account the viscosity suitable for application of the coloring composition. The content of the aqueous organic solvent in the coloring composition is preferably 10% by mass or less, more preferably less than 3% by mass, even more preferably less than 1% by mass, and particularly preferably 0% by mass.

[0146] (Other Compounding Agents) In addition to the above-mentioned coloring agent, dispersant, and aqueous dispersion medium, other compounding agents can be compounded in the coloring composition of the present invention, as long as the effects of the present invention are not impaired. Examples of other compounding agents include surfactants, antifoaming agents, mildew inhibitors, preservatives, rust inhibitors, chelating agents, water-soluble UV absorbers, water-soluble polymer compounds (excluding the above-mentioned dispersants), water-dispersible resins (excluding the above-mentioned dispersants), antioxidants, etc.

[0147] Examples of the surfactant include anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, silicone surfactants, and fluorine-based surfactants. Examples of anionic surfactants include alkyl sulfocarboxylates, α-olefin sulfonates, polyoxyethylene alkyl ether acetates, polyoxyethylene alkyl ether sulfates, polyoxyethylene dinonylphenyl ether sulfates, polyoxyethylene lauryl ether sulfates, N-acylamino acids or salts thereof, N-acylmethyl taurines, alkyl sulfates, polyoxyalkyl ether sulfates, alkyl sulfates, polyoxyethylene alkyl ether phosphates, rosin acid soaps, castor oil sulfates, lauryl alcohol sulfates, alkylphenol phosphates, alkyl phosphates, alkylaryl sulfonates, diethyl sulfosuccinates, diethylhexyl sulfosuccinates, and dioctyl sulfosuccinates. Among these, polyoxyethylene dinonylphenyl ether sulfates, polyoxyethylene lauryl ether sulfates, and dioctyl sulfosuccinates are preferred.

[0148] Examples of nonionic surfactants include ether surfactants such as polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, polyoxyethylene alkyl ether, polyoxyethylene acetylene glycol ether, and polyoxyethylene distyrenated phenyl ether; ester surfactants such as polyoxyethylene oleate, polyoxyethylene distearate, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, polyoxyethylene monooleate, and polyoxyethylene stearate; and acetylene glycol (alcohol) surfactants such as 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, and 3,5-dimethyl-1-hexyne-3-ol. Among these, Surfynol, polyoxyethylene acetylene glycol ether, and polyoxyethylene distyrenated phenyl ether are preferred.

[0149] Examples of cationic surfactants include 2-vinylpyridine derivatives, poly(4-vinylpyridine) derivatives, etc. Examples of amphoteric surfactants include lauryl dimethylaminoacetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine, coconut oil fatty acid amidopropyl dimethylaminoacetic acid betaine, polyoctyl polyaminoethyl glycine, and imidazoline derivatives.

[0150] Examples of silicone surfactants include polyether-modified siloxanes, polyether-modified polydimethylsiloxanes, etc. Examples of fluorine-based surfactants include perfluoroalkyl sulfonic acid compounds, perfluoroalkyl carboxylic acid compounds, perfluoroalkyl phosphate ester compounds, perfluoroalkyl ethylene oxide adducts, and polyoxyalkylene ether polymer compounds having perfluoroalkyl ether groups on the side chains.

[0151] Examples of the antifoaming agent include silicone-based antifoaming agents, silica mineral oil-based antifoaming agents, olefin-based antifoaming agents, and acetylene-based antifoaming agents.

[0152] Examples of the antifungal agent include sodium dehydroacetate, sodium benzoate, sodium pyridinethione-1-oxide, p-hydroxybenzoic acid ethyl ester, 1,2-benzisothiazolin-3-one and its salts.

[0153] Examples of preservatives include organic sulfur compounds, organic nitrogen sulfur compounds, organic halogen compounds, haloaryl sulfone compounds, iodopropargyl compounds, haloalkylthio compounds, nitrile compounds, pyridine compounds, 8-oxyquinolines, benzothiazole compounds, isothiazolinone compounds, dithiols, pyridine oxide compounds, nitropropane compounds, organic tin compounds, phenol compounds, quaternary ammonium salt compounds, triazine compounds, thiazine compounds, anilides, adamantane compounds, dithiocarbamates, brominated indanone compounds, benzyl bromoacetate compounds, and inorganic salt compounds. A specific example of an organic halogen compound is sodium pentachlorophenol. A specific example of a pyridine oxide compound is sodium 2-pyridinethiol-1-oxide. Specific examples of the isothiazoline compound include 1,2-benzisothiazolin-3-one, 2-n-octyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one magnesium chloride, 5-chloro-2-methyl-4-isothiazolin-3-one calcium chloride, and 2-methyl-4-isothiazolin-3-one calcium chloride.

[0154] Examples of the rust inhibitor include acid sulfite, sodium thiosulfate, ammonium thioglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.

[0155] Examples of the chelating agent include disodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, and sodium uracildiacetate.

[0156] Examples of water-soluble ultraviolet absorbers include sulfonated benzophenone compounds, benzotriazole compounds, salicylic acid compounds, cinnamic acid compounds, and triazine compounds.

[0157] The water-soluble polymer compound (excluding the dispersant) is not particularly limited as long as it is a polymer that dissolves in water, but anionic polymers and nonionic polymers are preferred from the viewpoint of dispersion stability. Examples of anionic polymers include cellulose derivatives such as carboxymethyl cellulose, acrylic acid derivatives such as polyacrylic acid, and polystyrene derivatives such as polystyrene sulfonate. Examples of nonionic polymers include polyethylene glycol, polyvinyl alcohol, polyvinylpyrrolidone, gelatin, etc.

[0158] The water-dispersible resin (excluding the dispersant) has the function of fixing the colorant in the coloring composition to the recording material by forming a film at room temperature. The resin used for the water-dispersible resin is not particularly limited, and examples thereof include urethane resins, polyester resins, acrylic resins, vinyl acetate resins, vinyl chloride resins, acrylic styrene resins, acrylic silicone resins, and styrene butadiene resins.

[0159] As the antioxidant, various organic and metal complex anti-fading agents can be used, examples of which include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines, and heterocycles.

[0160] When the coloring composition of the present invention is used for inkjet recording, it is preferable that the content of inorganic impurities, such as chlorides (e.g., sodium chloride) and sulfates (e.g., sodium sulfate) of metal cations, in the coloring composition be low. Inorganic impurities are often present in the bulk powder of the colorant, and it is also preferable to purify the bulk powder as needed. The inorganic impurity content is approximately 1% or less based on the total mass of the colorant, with the lower limit being below the detection limit of the analytical instrument, i.e., 0%. Methods for removing inorganic impurities from the colorant include, for example, stirring a dried product or wet cake of the dye in an appropriate water-soluble solvent (e.g., an alcohol having 1 to 4 carbon atoms, such as methanol) and, if necessary, a mixed solvent of a water-soluble organic solvent and water, filtering and separating the precipitate, and drying it; or desalting the inorganic impurities using an ion exchange resin.

[0161] The pH of the colored composition of the present invention is usually 7 to 11, preferably 8 to 10, for the purpose of improving storage stability and compatibility with inkjet printer components. The surface tension of the colored composition is usually 10 mN / m to 50 mN / m, preferably 20 mN / m to 40 mN / m. Furthermore, the viscosity (25°C) of the colored composition is usually 2 mPa·s to 30 mPa·s, preferably 3 mPa·s to 20 mPa·s.

[0162] [Method for Producing Colored Composition] Examples of a method for producing a colored composition containing the yellow azo pigment, a dispersant, and an aqueous dispersion medium include a production method (Aspect 1) having a step of preparing a neutralized product of the block copolymer and a step of mixing the neutralized product of the block copolymer, the yellow azo pigment, and the aqueous dispersion medium; and a production method (Aspect 2) having a step of mixing the yellow azo pigment, the block copolymer, a neutralizing agent, and the aqueous dispersion medium.

[0163] Examples of methods for preparing the neutralized block copolymer include a method in which a monomer having a neutralized acidic group is used when polymerizing the block copolymer (Method 1); and a method in which the block copolymer is mixed with a neutralizing agent (Method 2).

[0164] The monomer used in Method 1 is not particularly limited as long as it is a monomer capable of forming a structural unit having a neutralized acidic group. Examples of neutralizing components for the acidic group include alkali metals, organic amines, and ammonia.

[0165] Examples of the monomer capable of forming the structural unit having a neutralized acidic group include compounds in which the acidic group of the monomer forming the structural unit (a-2) is neutralized with an alkali metal, an organic amine, or ammonia.

[0166] (Neutralizing Agent) The neutralizing agent used in Production Method 2 of Production Method Aspect 1 or Production Method Aspect 2 can be a compound capable of neutralizing the acidic group in the structural unit (a-2) of the block copolymer. The amount of the neutralizing agent is adjusted so that the degree of neutralization of the acidic group in the structural unit (a-2) of the block copolymer is more than 50 mol %.

[0167] Examples of the neutralizing agent include compounds containing alkali metals, organic amines, ammonia, etc. Examples of the compounds containing alkali metals include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; alkali metal carbonates such as lithium carbonate, sodium carbonate, sodium bicarbonate, and potassium carbonate; and alkali metal salts of organic acids such as sodium silicate and potassium acetate. Examples of the organic amines include alkanolamines such as monoethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, monopropanolamine, dipropanolamine, tripropanolamine, N-methylethanolamine, and 2-(dimethylamino)ethanol; and alkylamines such as monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, and triethylamine.

[0168] In the production method, the method for mixing the yellow azo pigment, block copolymer, neutralizer, and aqueous dispersion medium is not particularly limited, and for example, a mixer / disperser such as a paint shaker, bead mill, ball mill, dissolver, or kneader can be used. The yellow azo pigment, block copolymer, neutralizer, and aqueous dispersion medium may be mixed together or separately. For example, the block copolymer, neutralizer, and aqueous dispersion medium may be mixed, and then this mixture may be mixed with the yellow azo pigment. Alternatively, the block copolymer may be mixed with a portion of the neutralizer and aqueous dispersion medium, and then this mixture may be mixed with the remaining neutralizer and yellow azo pigment.

[0169] The coloring composition may contain a dispersant, a colorant, an aqueous dispersion medium, and, if necessary, other compounding ingredients. The coloring composition is preferably filtered after mixing.

[0170] From the viewpoint of the storage stability and jetting properties of the coloring composition, the number-average particle diameter of the colorant in the coloring composition is usually 200 nm or less, preferably 50 nm to 200 nm, more preferably 70 nm to 170 nm, and even more preferably 80 nm to 130 nm. If the average particle diameter of the colorant is 200 nm or less, the dispersion becomes more stable. Furthermore, if the average particle diameter of the colorant is 50 nm or more, the stability of the colorant becomes better, and the storage stability of the ink is further improved.

[0171] The coloring composition can be used in various fields, such as writing, printing, information recording, and textile printing, and is particularly suitable for inkjet recording methods in printing, information recording, and textile printing.

[0172] <Colored Body> The colored body of the present invention refers to a substance colored with the coloring composition. The material of the colored body is not particularly limited as long as it is a substance that can be colored with the coloring composition. Examples of the colored body include a colored body (recorded material) colored by the inkjet recording method described below.

[0173] <Inkjet Recording Method> The inkjet recording method of the present invention is a method of performing recording by ejecting droplets of the coloring composition (hereinafter, may be referred to as "inkjet ink" or "ink") in response to a recording signal and allowing the droplets to adhere to a recording material. There are no particular restrictions on the ink nozzles and the like used during recording, and they can be appropriately selected depending on the purpose.

[0174] The recording method may employ any known method, such as a charge control method that utilizes electrostatic attraction to eject ink, a drop-on-demand method (pressure pulse method) that utilizes the vibration pressure of a piezoelectric element, an acoustic inkjet method in which an electric signal is converted into an acoustic beam and irradiated onto ink, and the resulting radiation pressure is used to eject the ink, or a thermal inkjet method, i.e., a bubble jet (registered trademark) method, in which ink is heated to form bubbles and the resulting pressure is used. Also included are methods such as a method in which inks with a low colorant content, called photo inks, are ejected in large numbers in small volumes, and a method in which multiple inks of substantially the same hue but different dye concentrations are used in combination to improve image quality.

[0175] The recording material is not particularly limited, and examples thereof include information recording sheets such as paper and film; nonwoven fabrics made of fibers such as cotton, viscose rayon, polynosic, cupra, polyester, nylon, wool, and silk; cloths (woven fabrics and knitted fabrics) made of yarns (twisted yarns and non-twisted yarns) made of the above fibers; leather; and substrates for color filters. Of these, information recording sheets are preferred.

[0176] Examples of information recording sheets include those in which an ink-receiving layer is provided on a substrate such as paper, synthetic paper, or film. The ink-receiving layer is provided, for example, by impregnating or coating the substrate with a cationic polymer, or by coating the surface of the substrate with inorganic fine particles such as porous silica, alumina sol, or special ceramics together with a hydrophilic polymer such as polyvinyl alcohol or polyvinylpyrrolidone. Sheets provided with such an ink-receiving layer are usually called inkjet paper, inkjet film, glossy paper, glossy film, or the like. These sheets have high surface gloss and excellent water resistance, making them suitable for recording photographic images.

[0177] Examples of information transmission sheets that do not have an ink-receiving layer include various papers such as coated paper and art paper used in applications such as gravure printing and offset printing; and cast coated paper used in label printing.

[0178] When a communication sheet having no ink-receiving layer is used, it is also preferable to subject the sheet to a surface modification treatment, preferably a known surface modification treatment selected from corona discharge treatment, plasma treatment, and flame treatment.

[0179] <Inkjet Printer> The inkjet printer of the present invention is an inkjet printer loaded with a container that stores the coloring composition. The inkjet printer includes a recording head that ejects ink (coloring composition) to record an image, and a container for storing the ink, and the container is equipped with a supply unit that supplies ink to the recording head. The inkjet printer also includes a control device, and a recording operation is performed by sending a recording signal from this control device to the recording head. When recording on a recording material using the inkjet recording method, for example, an inkjet printer loaded with a container that stores the coloring composition is used. The container that stores the coloring composition is loaded at a predetermined position in the inkjet printer.

[0180] The coloring composition can be used as a yellow ink, and can also be combined with a black ink, a cyan ink, and a magenta ink to form an ink set having four types of inks for full-color recording. The ink set is an ink set in which at least one of these four types of ink is the ink composition. Furthermore, the ink set may further contain inks of other colors, such as green, blue (or violet), and red (or orange), as needed, in order to express richer colors. Each color of ink is poured into a respective container, and inkjet recording is performed by loading each container into a predetermined position in an inkjet printer.

[0181] The coloring composition of the present invention can produce high-quality printed matter with high print density and excellent fastness such as water resistance, light resistance, and abrasion resistance, as well as high image stability, not only when used on inkjet paper but also when used on plain paper. Furthermore, even when the type of paper is changed, a printed matter with high color stability and little change in hue can be produced.

[0182] The present invention will be described in more detail based on specific examples. The present invention is not limited to the following examples and can be practiced with appropriate modifications within the scope of the present invention. The polymerization rate, weight average molecular weight (Mw), molecular weight distribution (Mw / Mn), acid value, viscosity and particle size of the colored composition were evaluated according to the following methods.

[0183] The meanings of the abbreviations are as follows: VP: N-vinyl-2-pyrrolidone CHA: cyclohexyl acrylate BA: n-butyl acrylate BzA: benzyl acrylate M11EGA: polyethylene glycol (degree of polymerization = 11) methyl ether acrylate (KOMERATE-A040TT, manufactured by Green Co., Ltd.) M3EGA: methoxytriethylene glycol acrylate AA: acrylic acid ATBSNa: sodium acrylamido tert-butylsulfonate MA: methyl acrylate BTEE: ethyl 2-methyl-2-n-butyltellanyl propionate AIBN: 2,2'-azobis(isobutyronitrile) DIW: ultrapure water MeOH: methanol MP: 1-methoxy-2-propanol KOH: potassium hydroxide DMAE: dimethylaminomethanol

[0184] [Evaluation Method] (Polymerization Rate) Using a nuclear magnetic resonance (NMR) measurement device (manufactured by Bruker Biospin, model: AVANCE500 (frequency 500 MHz)), 1 H-NMR was measured (solvent: CDCl, internal standard: TMS). For the obtained NMR spectrum, the integral ratio of the peak derived from the monomer to the peak derived from the polymer was determined, and the polymerization rate of the monomer was calculated.

[0185] (Weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn)) These were determined by gel permeation chromatography (GPC) using a high-performance liquid chromatograph (Tosoh Corporation, Model: HLC8320). A single SHODEX KF-603 (Φ6.0 mm x 150 mm) (SHODEX Corporation) column was used, with a mobile phase of lithium bromide (30 mmol / L)-acetic acid (30 mmol / L)-N-methylpyrrolidone and a differential refractive index detector. The measurement conditions were a column temperature of 40°C, a sample concentration of 100 mg / mL, a sample injection volume of 10 μL, and a flow rate of 0.2 mL / min. A calibration curve was prepared using polystyrene (molecular weights: 705,000, 37,900, 19,920, 10,200, 4,910, 2,630, and 1,150) as a standard substance, and Mw and Mn were measured. The molecular weight distribution (Mw / Mn) was calculated from these measured values.

[0186] (Acid Value) The acid value represents the mass of KOH required to neutralize the acidic components per 1 g of solid content. A measurement sample was dissolved in tetrahydrofuran, and a few drops of 1.0 w / v % phenolphthalein ethanol (90) solution was added to the resulting solution as an indicator, followed by neutralization titration with KOH (0.1 mol / L)-2-propanol solution. The point at which a slight reddish color remained was taken as the titration endpoint, and the acid value was calculated using the following formula: A = 56.11 × Vs × 0.1 × f / w A: acid value (mg KOH / g) Vs: amount (mL) of KOH (0.1 mol / L)-2-propanol solution used for titration f: titer of KOH (0.1 mol / L)-2-propanol solution w: mass (g) of measurement sample (solid content equivalent)

[0187] (Viscosity) Using an E-type viscometer (trade name: RE-80L, manufactured by Toki Sangyo Co., Ltd.) and a cone rotor (0.8° x R24), the viscosity (mPa s) was measured at 25 ° C. and a rotor rotation speed of 12 rpm. The viscosity of the colored compositions was measured immediately after preparation and after storage at 40 ° C. for one week. Note that the rotor rotation speed was changed to 6 rpm for colored compositions No. 3 (after one week of storage at 40 ° C.) and 20 (immediately after preparation), the rotor rotation speed was changed to 3 rpm for colored compositions No. 3 (immediately after preparation), 6 (immediately after preparation, after one week of storage at 40 ° C.) and 13 (immediately after preparation), the rotor rotation speed was changed to 1.5 rpm for colored composition No. 14 (immediately after preparation), the rotor rotation speed was changed to 0.6 rpm for colored composition No. 12 (after one week of storage at 40 ° C.), and the rotor rotation speed was changed to 0.6 rpm for colored composition No. 14 (immediately after preparation). For No. 21 (immediately after preparation), the rotor rotation speed was changed to 0.3 rpm.

[0188] (Particle size) Using a concentrated particle size analyzer (product name: FPAR-1000, manufactured by Otsuka Electronics), the particle size was measured at 25°C. The sample was diluted with DIW as necessary. The measurement was carried out on the colored composition immediately after preparation and on the colored composition stored at 40°C for one week after preparation.

[0189] <Synthesis of Copolymer> (Copolymer No. 1) 3.9 g of VP, 0.6 g of CHA, 0.01 g of AIBN, and 4.5 g of DIW were charged into a flask equipped with an argon gas inlet tube and a stirrer, and after replacing the atmosphere with nitrogen, 0.45 g of BTEE was added. The mixture was reacted at 55° C. for 7 hours to polymerize the B block. The conversion was 95.5%.

[0190] A mixed solution of 3.0 g of M11EGA, 1.5 g of AA, 6.0 g of MA, 0.02 g of AIBN, and 10.0 g of MeOH, which had been previously purged with argon, was added to the reaction solution, and the mixture was reacted at 55° C. for 20 hours to polymerize the A block. The polymerization rate was 95.5%.

[0191] After the reaction was completed, the reaction solution was poured into stirred n-heptane. The precipitated polymer was filtered by suction and dried to obtain Copolymer No. 1. The obtained Copolymer No. 1 had an Mw of 7038, an Mw / Mn of 1.37, and an acid value of 93 mgKOH / g.

[0192] (Copolymers Nos. 2 to 12) Copolymers Nos. 2 to 12 were produced in the same manner as in the production of Copolymer No. 1. Table 1 shows the monomers, organotellurium compounds, azo-based polymerization initiators, solvents, reaction conditions, and polymerization rates used. Tables 2 and 3 show the composition, Mw, Mw / Mn, and acid value of each copolymer. The content of each structural unit in the copolymer was calculated from the charge ratio of the monomers used in the polymerization reaction and the polymerization rate.

[0193] <Synthesis of Neutralized Copolymer> (Neutralized Copolymer Nos. 13 and 14) Neutralized copolymer Nos. 13 and 14 were prepared in the same manner as in the production of Copolymer No. 1. Table 1 shows the monomers, organotellurium compound, azo-based polymerization initiator, solvent, reaction conditions, and polymerization rate used. The monomers were blended so that the acid value of the copolymer before neutralization was 80 mg KOH / g. Table 3 shows the composition, Mw, and Mw / Mn of each copolymer. The content of each structural unit in the copolymer was calculated from the charge ratio and polymerization rate of the monomers used in the polymerization reaction, and was calculated by converting the structural unit derived from sodium acrylamido tert-butylsulfonate into the structural unit derived from acrylamido tert-butylsulfonic acid. The Mw and Mw / Mn of Neutralized Copolymer Nos. 13 and 14 in Table 3 are measured values ​​for the neutralized copolymer.

[0194]

[0195]

[0196]

[0197] Neutralization of Copolymer (Neutralized Copolymer No. 5) A mixture of 14.6 g of Copolymer No. 5, 0.5 g of KOH, and 28.3 g of DIW was placed in a flask equipped with a stirrer and stirred at room temperature (25° C.). The neutralized Copolymer No. 5 had an acid value of 127 mg KOH / g.

[0198] (Neutralized Copolymer Nos. 6, 7, 11, and 12) In the same manner as in Neutralized Copolymer No. 5, a portion of the acidic groups of Copolymer Nos. 6, 7, 11, and 12 were neutralized to prepare Neutralized Copolymer Nos. 6, 7, 11, and 12. Table 4 shows the copolymers, solvents, and neutralizing agents used. Table 4 also shows the acid values.

[0199]

[0200] <Preparation of Colored Compositions> Colored compositions were prepared using the copolymers Nos. 1 to 4, 8 to 10 and neutralized copolymers Nos. 5 to 7 and 11 to 14 obtained above as dispersants. Specifically, yellow azo pigments PY-150 (Pigment Yellow 150, average particle size 119 nm, manufactured by LANXESS, Bayscript Yellow 4GF), PY-155 (Pigment Yellow 155, manufactured by HEUBACH, INK JET YELLOW 4GC, average particle size 90 nm), or PY-180 (Pigment Yellow 180, manufactured by HEUBACH, INK JET YELLOW HG01, average particle size 72 nm), copolymers or neutralized copolymers, neutralizers, and deionized water were mixed to obtain the formulations shown in Tables 5 and 6, and 0.3 mm zirconia beads were added. The mixture was milled using a bead mill (trade name: DISPERMAT CA, VMA-GETZMANN) to obtain the formulations shown in Tables 5 and 6. The mixture was stirred for 5 hours in a dispersion mixer (manufactured by Sigma-Aldrich GmbH) to thoroughly disperse the beads. After stirring was completed, the beads were filtered off to prepare colored compositions Nos. 1 to 25. The obtained dispersion compositions were subjected to viscosity and particle size measurements, and the results are shown in Tables 5 and 6. In Table 6, "gel" indicates that the colored composition gelled and the viscosity could not be measured, "undispersible" indicates that the yellow azo pigment could not be sufficiently dispersed, and ">2000" indicates that the viscosity exceeded 2,000 mPa s even when the rotor rotation speed was changed.

[0201]

[0202]

[0203] Coloring compositions Nos. 1 to 11 contain a yellow azo pigment, a dispersant, and water, wherein the dispersant is a neutralized product of a block copolymer having an A block containing a structural unit (a-1) having a group represented by formula (1) and a structural unit (a-2) having an acidic group, and a B block containing a structural unit (b-1) having a nitrogen-containing heterocyclic group and a structural unit (b-2) having an aliphatic hydrocarbon group, wherein the content of the structural unit (b-1) in the block copolymer is 51% to 99% by mass relative to 100% by mass of the B block, the acid value of the block copolymer is 50 mg KOH / g or more, and the dispersant neutralizes more than 50 mol % of the acidic groups in the structural unit (a-2) of the block copolymer. These coloring compositions Nos. 1 to 11 exhibited high dispersibility of the yellow azo pigment and excellent dispersion stability.

[0204] Colored compositions Nos. 12 and 17 to 19 are those in which, in the neutralized copolymer used as the dispersant, 50 mol % or less of the acidic groups in the structural unit (a-2) are neutralized.

[0205] Colored compositions Nos. 13 and 14 are examples where copolymers Nos. 6 and 7 used in the dispersants do not have a structural unit (a-1) having a group represented by formula (1) in the A block. Colored compositions Nos. 15, 16, 21, and 23 to 25 are examples where copolymers Nos. 8, 9, 11, and 14 used in the dispersants do not have a structural unit (b-2) having an aliphatic hydrocarbon group in the B block. Colored composition No. 20 is an example where copolymer No. 10 used in the dispersant has an acid value before neutralization of less than 50 mg KOH / g. Colored composition No. 22 is an example where copolymer No. 12 used in the dispersant has a content of structural units (b-1) having a nitrogen-containing heterocyclic group in the B block of less than 51% by mass. These colored compositions Nos. 12 to 16 and 18 to 21 had poor dispersion stability. Furthermore, colored composition No. Coloring compositions Nos. 17, 22 to 25 were unable to disperse PY-150, PY-155, or PY-180. Coloring compositions Nos. 1, 9, and 10 differ only in the type of colorant. When comparing the difference in particle size of the pigment before and after dispersion in the coloring compositions, coloring composition No. 1 had the same particle size before and after dispersion. This demonstrates that the dispersant used in the present invention works particularly well for azomethine metal complex pigments.

[0206] The present invention includes the following aspects.

[0207] (Aspect 1) A colored composition comprising a yellow azo metal complex pigment, a dispersant, and an aqueous dispersion medium, wherein the dispersant is a neutralized product of a block copolymer having an A block containing a structural unit (a-1) having a group represented by formula (1) and a structural unit (a-2) having an acidic group, and a B block containing a structural unit (b-1) having a nitrogen-containing heterocyclic group and a structural unit (b-2) having an aliphatic hydrocarbon group, wherein the content of the structural unit (b-1) in the block copolymer is 51% to 99% by mass relative to 100% by mass of the B block, the acid value of the block copolymer is 50 mgKOH / g or more, and the dispersant is a colored composition in which more than 50 mol % of the acidic groups in the structural unit (a-2) of the block copolymer have been neutralized. 12 O) m1 -R 11(1) [In formula (1), R 11 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 12 represents an alkylene group having 1 to 3 carbon atoms. m1 represents an integer of 2 to 30. 12 may be the same or different. * represents a bond.]

[0208] (Aspect 2) The colored composition according to aspect 1, wherein the dispersant is a block copolymer in which an acidic group of the structural unit (a-2) of the block copolymer is neutralized with at least one selected from the group consisting of an alkali metal, an organic amine, and ammonia.

[0209] (Embodiment 3) The colored composition according to embodiment 1 or 2, wherein the content of the structural unit (a-1) is 10% by mass to 70% by mass relative to 100% by mass of the A block.

[0210] (Aspect 4) The colored composition according to any one of Aspects 1 to 3, wherein the mass ratio of the A block to the B block (A block / B block) in the block copolymer is 50 / 50 to 99 / 1.

[0211] (Aspect 5) The colored composition according to any one of Aspects 1 to 4, wherein the structural unit (a-1) is a structural unit represented by formula (2).

[0212] [In formula (2), R 21 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 22 represents an alkylene group having 1 to 3 carbon atoms. 23 represents a hydrogen atom or a methyl group. m2 represents an integer of 2 to 30. 22 may be the same or different.

[0213] (Aspect 6) The colored composition according to any one of aspects 1 to 5, wherein the structural unit (a-2) is a structural unit represented by formula (3).

[0214] [In formula (3), R 31 represents a single bond or a divalent organic group. 32represents a hydrogen atom or a methyl group. 3 represents an acidic group.

[0215] (Aspect 7) The colored composition according to any one of Aspects 1 to 6, wherein the structural unit (b-1) is a structural unit represented by formula (4).

[0216] [In formula (4), R 41 , R 42 , R 43 and R 44 are the same or different and represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms which may have a substituent; m4 represents an integer of 0 to 4; and n4 represents an integer of 1 to 3.

[0217] (Embodiment 8) The colored composition according to any one of embodiments 1 to 7, wherein the structural unit (b-2) is a structural unit represented by formula (5).

[0218] [In formula (5), R 51 represents an aliphatic hydrocarbon group. 5 represents O or NH. 52 represents a hydrogen atom or a methyl group.

[0219] (Aspect 9) The colored composition according to any one of aspects 1 to 8, wherein the block copolymer has a weight average molecular weight (Mw) of 5,000 to 40,000.

[0220] (Aspect 10) The colored composition according to any one of aspects 1 to 9, wherein the block copolymer is obtained by living polymerization and has a molecular weight distribution (Mw / Mn) of 2.5 or less.

[0221] (Embodiment 11) The colored composition according to any one of embodiments 1 to 10, wherein the yellow azo pigment is at least one selected from the group consisting of azomethine metal complex pigments and acetoacetate arylide pigments.

[0222] (Aspect 12) The coloring composition according to any one of aspects 1 to 11, wherein the yellow azo pigment is at least one selected from the group consisting of C.I. Pigment Yellow 117, C.I. Pigment Yellow 129, C.I. Pigment Yellow 150, C.I. Pigment Yellow 153, C.I. Pigment Yellow 155, and C.I. Pigment Yellow 180.

[0223] (Aspect 13) The colored composition according to any one of aspects 1 to 12, wherein the content of the aqueous organic solvent in the colored composition is 10% by mass or less.

[0224] (Aspect 14) The coloring composition according to any one of aspects 1 to 13, which is for use in an inkjet ink.

[0225] (Aspect 15) A method for producing a colored composition, comprising the steps of mixing a yellow azo pigment, a block copolymer, a neutralizing agent, and an aqueous dispersion medium, wherein the block copolymer comprises an A block containing a structural unit (a-1) having a group represented by Formula (1) and a structural unit (a-2) having an acidic group, and a B block containing a structural unit (b-1) having a nitrogen-containing heterocyclic group and a structural unit (b-2) having an aliphatic hydrocarbon group, the content of the structural unit (b-1) being 51% to 99% by mass relative to 100% by mass of the B block, the acid value of the block copolymer being 50 mgKOH / g or greater, and the amount of the neutralizing agent added being adjusted so that the degree of neutralization of the acidic groups in the structural units (a-2) of the block copolymer is greater than 50 mol %. 12 O) m1 -R 11 (1) [In formula (1), R 11 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 12 represents an alkylene group having 1 to 3 carbon atoms. m1 represents an integer of 2 to 30. 12 may be the same or different. * represents a bond.]

Claims

1. A coloring composition comprising a yellow azo pigment, a dispersant, and an aqueous dispersion medium, wherein the dispersant is a neutralized product of a block copolymer having an A block containing a structural unit (a-1) having a group represented by formula (1) and a structural unit (a-2) having an acidic group, and a B block containing a structural unit (b-1) having a nitrogen-containing heterocyclic group and a structural unit (b-2) having an aliphatic hydrocarbon group, the content of the structural unit (b-1) in the block copolymer being 51% by mass to 99% by mass in 100% by mass of the B block, the acid value of the block copolymer being 50 mgKOH / g or more, and the dispersant is a coloring composition in which more than 50 mol % of the acidic groups in the structural unit (a-2) of the block copolymer have been neutralized. 12 O) m1 -R 11 (1) [In formula (1), R 11 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 12 represents an alkylene group having 1 to 3 carbon atoms. m1 represents an integer of 2 to 30. 12 may be the same or different. * represents a bond.] 2. The colored composition according to claim 1, wherein the dispersant is obtained by neutralizing an acidic group possessed by the structural unit (a-2) of the block copolymer with at least one member selected from the group consisting of alkali metals, organic amines and ammonia.

3. The colored composition according to claim 1 or 2, wherein the content of the structural unit (a-1) is 10% by mass to 70% by mass in 100% by mass of the A block.

4. The colored composition according to claim 1 or 2, wherein the mass ratio of the A block to the B block (A block / B block) in the block copolymer is 50 / 50 to 99 / 1.

5. The colored composition according to claim 1 or 2, wherein the structural unit (a-1) is a structural unit represented by formula (2). [In formula (2), R 21 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 22 represents an alkylene group having 1 to 3 carbon atoms. 23 represents a hydrogen atom or a methyl group. m2 represents an integer of 2 to 30. 22 may be the same or different.

6. The colored composition according to claim 1 or 2, wherein the structural unit (a-2) is a structural unit represented by formula (3). [In formula (3), R 31 represents a single bond or a divalent organic group. 32 represents a hydrogen atom or a methyl group. 3 represents an acidic group.

7. The colored composition according to claim 1 or 2, wherein the structural unit (b-1) is a structural unit represented by formula (4). [In formula (4), R 41 , R 42 , R 43 and R 44 are the same or different and represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms which may have a substituent; m4 represents an integer of 0 to 4; and n4 represents an integer of 1 to 3.] 8. The colored composition according to claim 1 or 2, wherein the structural unit (b-2) is a structural unit represented by formula (5). [In formula (5), R 51 represents an aliphatic hydrocarbon group. 5 represents O or NH. 52 represents a hydrogen atom or a methyl group.

9. The colored composition according to claim 1 or 2, wherein the weight average molecular weight (Mw) of the block copolymer is 5,000 to 40,000.

10. The colored composition according to claim 1 or 2, wherein the block copolymer is obtained by living polymerization and has a molecular weight distribution (Mw / Mn) of 2.5 or less.

11. The coloring composition according to claim 1 or 2, wherein the yellow azo pigment is at least one selected from the group consisting of azomethine metal complex pigments and acetoacetate arylide pigments.

12. The coloring composition according to claim 1 or 2, wherein the yellow azo pigment is at least one selected from the group consisting of C.I. Pigment Yellow 117, C.I. Pigment Yellow 129, C.I. Pigment Yellow 150, C.I. Pigment Yellow 153, C.I. Pigment Yellow 155 and C.I. Pigment Yellow 180.

13. The coloring composition according to claim 1 or 2, wherein the content of the aqueous organic solvent in the coloring composition is 10 mass % or less.

14. The coloring composition according to claim 1 or 2, which is for use in an ink-jet ink.

15. A method for producing a colored composition, comprising the steps of mixing a yellow azo pigment, a block copolymer, a neutralizing agent, and an aqueous dispersion medium, wherein the block copolymer has an A block containing a structural unit (a-1) having a group represented by formula (1) and a structural unit (a-2) having an acidic group, and a B block containing a structural unit (b-1) having a nitrogen-containing heterocyclic group and a structural unit (b-2) having an aliphatic hydrocarbon group, the content of the structural unit (b-1) being 51% to 99% by mass in 100% by mass of the B block, the acid value of the block copolymer being 50 mgKOH / g or more, and the amount of the neutralizing agent being adjusted so that the degree of neutralization of the acidic group of the structural unit (a-2) of the block copolymer is more than 50 mol%. *-(R 12 O) m1 -R 11 (1) [In formula (1), R 11 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 12 represents an alkylene group having 1 to 3 carbon atoms. m1 represents an integer of 2 to 30. 12 may be the same or different. * represents a bond.]

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