JP6717892B2 - Ink composition, ink set, inkjet recording method, and colored body - Google Patents

Description

The present invention relates to an ink composition, an ink set, an inkjet recording method, and a colored body.

Inkjet recording methods are becoming more widely used for home use, office use, photographic use, and outdoor use. Along with this, weathering (light) resistance and storability of printed matter are becoming important.
As a colorant used for inkjet recording, a water-soluble dye and a pigment which is substantially unnecessary for water are mainly used. Of these, the former is said to be inferior in light resistance, and development of an ink composition using a pigment is in progress due to a strong demand for light resistance.

Examples of pigments used in the ink composition used for inkjet recording include thioindigo pigments, soluble azo lake pigments, insoluble azo pigments, and quinacridone pigments. Among these, quinacridone pigments (for example, CI pigment violet 19, CI pigment red 122, etc.) are said to have excellent light resistance.

However, quinacridone pigments are generally known to have the drawbacks that they are too bluish for use as magenta inks and have low color density. For this reason, the hue is often adjusted by using it in combination with a yellowish red coloring material, and is often used as a magenta ink. Examples of such a material include solid solution pigments composed of two or more kinds of quinacridone pigments.
For example, Patent Documents 1 and 2 disclose aqueous inkjet recording inks containing a solid solution pigment of a dimethylquinacridone pigment and an unsubstituted quinacridone pigment.

Patent Document 3 discloses that a water-based ink for inkjet recording using a naphthol AS-based monoazo pigment as an insoluble monoazo pigment and a colored recorded image using the same have excellent color forming properties.

Further, in Patent Documents 4 to 6, C.I. I. Pigment Red 122 and C.I. as an insoluble monoazo pigment. I. Pigment Red 185, C.I. I. Pigment Red 269, C.I. I. As a water-based inkjet recording ink that is mixed and used with Pigment Red 146 and the like, an inkjet magenta ink is disclosed in which the coloring property of a colored recording image is enhanced and the light resistance is also improved.

Further, Patent Document 7 discloses a water-based ink for ink jet recording which uses a quinacridone pigment and a red pigment having a chemical structure different from quinacridone in addition to the insoluble monoazo pigment.

Further, Patent Document 8 discloses an aqueous inkjet ink composition containing two kinds of azo pigments as a coloring component.

JP, 10-219166, A JP-A-11-49998 JP 2007-246791 A JP, 2006-57044, A JP, 2011-149015, A Special table 2011-526322 gazette JP, 2009-173696, A JP2012-184334A

The present invention is an ink composition having excellent storage stability, redispersibility, and filterability, and having a good balance of color development, saturation, and light resistance, an inkjet recording method using the same, and coloring colored by these. The challenge is to provide the body.

The present inventors have conducted intensive studies to solve the above problems, and as a result, found that the above problems can be solved by an ink composition containing a specific azo pigment and a quinacridone pigment as colorants, Was completed.
That is, the present invention relates to the following [1] to [ 21 ].

[1]
As a colorant, C.I. I. Pigment Red 150 and C.I. I. Containing a quinacridone pigment selected from pigment and water ,
The quinacridone pigment is C.I. I. Pigment Red 122,
C. in the total mass of the colorant. I. Pigment Red 150 and the content ratio of the quinacridone pigment are 50/50 to 20/80 on a mass basis,
A colored dispersion liquid in which the average particle diameter of the colorant is 50 to 200 nm .
[2 ]
An ink composition for inkjet recording, containing the colored dispersion according to the above [1 ] and a water-soluble organic solvent.
[ 3 ]
The ink composition according to the above [ 2 ], wherein the total content of the colorant contained in the ink composition is 0.5 to 7% by mass based on the total mass of the ink composition .
[4 ]
The ink composition according to the above [ 2 ] or [3] , wherein the water-soluble organic solvent is at least one selected from the group consisting of glycol ethers and alkanediols.
[ 5 ]
The glycol ether is ethylene glycol monoallyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monohexyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monobutyl ether, and propylene glycol monopropyl ether. The ink composition according to the above [ 4 ], which is at least one selected from the group consisting of:
[ 6 ]
The alkanediols are 1,2-pentanediol, 1,2-hexanediol, 2-methyl-2,4-pentanediol, 2-ethyl-1,3-hexanediol, and 2,4-diethyl-1, The ink composition according to the above [ 4 ] or [ 5 ], which is at least one selected from the group consisting of 5-pentanediol.
[ 7 ]
The ink composition according to any one of the above [ 2 ] to [ 6 ], which further contains a surfactant.
[ 8 ]
The ink composition according to the above [ 7 ], wherein the surfactant is at least one selected from the group consisting of an anionic surfactant and a nonionic surfactant.
[ 9 ]
The above-mentioned [ 8 ], wherein the anionic surfactant is at least one selected from the group consisting of polyoxyethylene dinonyl phenyl ether sulfate, polyoxyethylene lauryl ether sulfate, and dioctyl sulfosuccinate. Ink composition.
[ 10 ]
[ 8 ] or [wherein the nonionic surfactant is at least one selected from the group consisting of polyoxyethylene acetylene glycol ether, polyoxyethylene distyrenated phenyl ether and polyoxyethylene tribenzylated phenyl ether. [9 ] The ink composition according to [ 9 ].
[ 11 ]
An inkjet recording ink set comprising a magenta ink composition, a cyan ink composition, a yellow ink composition, and a black ink composition,
An ink set used for inkjet recording, wherein the magenta ink composition is the ink composition according to any one of [ 2 ] to [ 10 ].
[ 12 ]
The yellow ink composition described above contains C.I. I. Pigment Yellow 74, C.I. I. Pigment Yellow 151, and C.I. I. Pigment Yellow 155, the ink set according to the above [ 11 ], which contains at least one kind selected from the group consisting of Pigment Yellow 155 as a colorant.
[ 13 ]
The cyan ink composition is C.I. I. Pigment Blue 15:3 and C.I. I. Pigment Blue 15:4, the ink set according to [ 11 ] or [ 12 ] above, which contains at least one kind selected from Pigment Blue 15:4.
[ 14 ]
An inkjet recording method in which droplets of the ink composition according to any one of [ 2 ] to [ 10 ] are ejected in accordance with a recording signal and adhered to a recording material to perform recording.
[ 15 ]
The inkjet recording method according to [ 14 ], wherein the recording material is an information transmission sheet.
[ 16 ]
The inkjet recording method according to [ 15 ], wherein the information transmission sheet is a sheet having an ink receiving layer containing a porous white inorganic substance.
[ 17 ]
The inkjet recording method according to [ 15 ], wherein the information transmission sheet is cast coated paper.
[ 18 ]
The inkjet recording method according to [ 15 ], wherein the information transmission sheet is coated paper or art paper.
[ 19 ]
The ink jet recording according to [ 17 ] or [ 18 ] above, wherein the information transmission sheet is a sheet that has been subjected to at least one type of surface modification treatment selected from corona discharge treatment, plasma treatment, and flame treatment. Method.
[ 20 ]
A colored body colored with the ink composition according to any one of [ 2 ] to [ 10 ].
[ 21 ]
An ink jet printer loaded with a container containing the ink composition according to any one of [ 2 ] to [ 10 ].

According to the present invention, an ink composition having excellent storage stability, redispersibility, and filterability, and having a good balance of color development, saturation, and light resistance, an inkjet recording method using the same, and coloring colored by these The body can provide.

Hereinafter, the ink composition of the present invention will be described in detail.
In the present specification, “CI” is an abbreviation for color index.
In addition, in the present specification, the “%” and the “parts” are described on a mass basis, including Examples and the like, unless otherwise specified.
Further, in the present specification, “CI pigment red” is hereinafter referred to as “PR” unless otherwise specified.

The colored dispersion liquid contains at least two kinds of colorants of PR150 and a quinacridone pigment, and further contains at least water.
Among these, as the quinacridone pigment, a di-substituted quinacridone pigment is preferable, and among them, a red di-substituted quinacridone pigment is more preferable. The di-substituted quinacridone pigment means a quinacridone pigment having a chemical structure in which any two hydrogen atoms on the benzene ring of unsubstituted quinacridone are replaced by a substituent other than hydrogen atom. Examples of the substituent other than a hydrogen atom include a methyl group, a methoxy group and a chlorine atom. Among them, at least one kind of pigment selected from PR122 and PR202 is preferable, and the former is more preferable in consideration of color developability.

PR150 is an insoluble monoazo red pigment. As the insoluble monoazo red pigment, pigments having various structural formulas are known, but the combination of PR150 and quinacridone pigment is particularly excellent in terms of hue, transparency, color developability, saturation, light resistance and the like.

The above-mentioned ink composition is an ink composition containing the above-mentioned colored dispersion liquid and a water-soluble organic solvent and used for inkjet recording.
The total content of the colorant contained in the ink composition is usually 0.5 to 7%, preferably 1 to 7%, more preferably 2 to 7%, further preferably 3 to 6%.
When it is 0.5% or more, the coloring property of the recorded image becomes good, and when it is 7% or less, the ejection property becomes good.

The content ratio of PR150 and the quinacridone pigment in the total mass of the colorant contained in the ink composition is usually 80/20 to 10/90, preferably 50/50 to 10/90, more preferably 50/50. ˜20/80, particularly preferably 50/50 to 30/70. With such a ratio, a recorded image having excellent storage stability, redispersibility, and filterability, and having a good balance of color development, saturation, and light resistance can be obtained.

The water-soluble organic solvent contained in the ink composition is not particularly limited, and examples thereof include C1-C6 alkanols such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, secondary butanol, and tertiary butanol; N, Carboxylic acid amides such as N-dimethylformamide and N,N-dimethylacetamide; lactams such as 2-pyrrolidone, N-methyl-2-pyrrolidone and N-methylpyrrolidin-2-one; 1,3-dimethylimidazolidine-2 -One, cyclic ureas such as 1,3-dimethylhexahydropyrimidin-2-one; acetone, 2-methyl-2-hydroxypentan-4-one, ketones or keto alcohols such as ethylene carbonate; tetrahydrofuran, dioxane Cyclic ethers such as ethylene glycol, diethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,4-butylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene. Mono-, oligo-, or polyalkylene glycols or thios having C2-C6 alkylene units such as glycol, polyethylene glycol (preferably having a molecular weight of 400, 800, 1540 or higher), polypropylene glycol, thiodiglycol, dithiodiglycol, etc. Glycol: C3-C9 polyol (triol) such as glycerin, diglycerin, hexane-1,2,6-triol, trimethylolpropane; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoallyl ether, ethylene glycol mono Isopropyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether (butyl carbitol), triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, propylene glycol monopropyl ether, prolene glycol mono Butyl ether, glycol ether such as dipropylene glycol monomethyl ether (preferably selected from the group consisting of C3-C10 mono, di, or triethylene glycol ether, and C4-C13 mono, di, or tripropylene glycol ether. Glycol ether); 1,2-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 2-methyl-2,4-pentanediol, 2-ethyl-1, C5-C9 alkane diols such as 3-hexanediol and 2,4-diethyl-1,5-pentanediol; γ-butyrolactone, dimethyl sulfoxide and the like; and the like. These water-soluble organic solvents may be used alone or in combination of two or more.

Among the above, as the water-soluble organic solvent, it is preferable to use at least one kind of water-soluble organic solvent selected from the group consisting of glycol ether and alkanediol.
Of these, glycol ethers include ethylene glycol monoallyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monohexyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monobutyl ether, and propylene glycol monopropyl ether. It is preferably at least one selected from the group consisting of ethers.
The alkanediols include 1,2-pentanediol, 1,2-hexanediol, 2-methyl-2,4-pentanediol, 2-ethyl-1,3-hexanediol, and 2,4-diethyl-. It is preferably at least one selected from the group consisting of 1,5-pentanediol.

The ink composition may contain a surfactant. Some surfactants have the effect of adjusting the permeability of the ink. The ink composition preferably contains such a surfactant. The surfactants may be used alone or in combination.
Examples of surfactants include known surfactants such as anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, silicone-based surfactants, fluorine-based surfactants and the like. Can be mentioned. Among these, at least one kind of surfactant selected from the group consisting of anionic surfactants and nonionic surfactants is preferable.
When the ink composition contains a surfactant, the total content of the surfactant is usually 0.1 to 3%, preferably 0.3 to 1.5% with respect to the total mass of the ink composition. is there.
When it is 0.1% or more, the effect as a surfactant can be obtained, and when it is 3% or less, the dispersion stability of the pigment can be maintained.

Examples of anionic surfactants include alkyl sulfocarboxylates, α-olefin sulfonates, polyoxyethylene alkyl ether acetates, polyoxyethylene alkyl ether sulfates, polyoxyethylene dinonyl phenyl ether sulfates, polyoxyethylene lauryl. Ether sulfate, N-acyl amino acid or its salt, N-acyl methyl taurine salt, alkyl sulfate polyoxyalkyl ether sulfate, alkyl sulfate polyoxyethylene alkyl ether phosphate, rosin acid soap, castor oil sulfate ester salt, Examples thereof include lauryl alcohol sulfate ester salt, alkylphenol type phosphate ester, alkyl type phosphate ester, alkylaryl sulfonate, diethylsulfosuccinate, diethylhexylsulfosuccinate, dioctylsulfosuccinate. Further, specific examples of commercially available products include, for example, Hitenol ^™ LA-10, LA-12, LA-16, NE-05, NE-15, NF-13, NF-17, Neohytenol ^™. Examples thereof include ECL-30S, ECL-45 (all manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), ADEKA COL EC-8600 (manufactured by ADEKA), and Perex OT-P (manufactured by Kao). Among these, at least one selected from the group consisting of polyoxyethylene dinonyl phenyl ether sulfate, polyoxyethylene lauryl ether sulfate, and dioctyl sulfosuccinate is preferable.
In the present specification, the superscript "TM" means a trademark.

Examples of the cationic surfactant include a 2-vinylpyridine derivative and a poly-4-vinylpyridine derivative.

Examples of nonionic surfactants include ethers such as polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, and polyoxyethylene alkyl ether ( For example, Sophthanol ^TM EP-5035, 7085, 9050 manufactured by Nippon Shokubai or Pluronic ^TM L-31, L-34, L-44 manufactured by Adeka); polyoxyethylene oleic acid ester, polyoxyethylene distearic acid ester, sorbitan Ester systems such as laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, polyoxyethylene monooleate, polyoxyethylene stearate; 2,4,7,9-tetramethyl-5-decyne- Acetylene glycol (alcohol) such as 4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3,5-dimethyl-1-hexyn-3-ol; polyoxyethylene acetylene glycol ether Polyoxyethylene distyrenated phenyl ether; Polyoxyethylene tribenzylated phenyl ether; Surfynol ^TM 104, 104PG50, 105PG50, 82, 420, 440, 465, 485 manufactured by Nissin Chemical Co.; Olphin ^TM STG; Polyglycol ether type (for example, TergItol ^™ 15-S-7 manufactured by SIGMA-ALDRICH); and the like. Among these, at least one selected from the group consisting of polyoxyethylene acetylene glycol ether, polyoxyethylene distyrenated phenyl ether, and polyoxyethylene tribenzylated phenyl ether is preferable.

As the amphoteric surfactant, lauryldimethylaminoacetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, coconut oil fatty acid amidopropyldimethylaminoacetic acid betaine, polyoctylpolyaminoethylglycine, imidazoline derivative, etc. Are listed.

Examples of silicone-based surfactants include polyether-modified siloxane and polyether-modified polydimethylsiloxane. Specific examples of commercially available products include, for example, BYK-347 (polyether-modified siloxane), BYK-345, BYK-348, and BYK-349 (polyether-modified polydimethylsiloxane), all manufactured by BYK Chemie. Etc.

As the fluorine-based surfactant, for example, a perfluoroalkyl sulfonic acid compound, a perfluoroalkyl carboxylic acid compound, a perfluoroalkyl phosphoric acid ester compound, a perfluoroalkyl ethylene oxide adduct, a perfluoroalkyl ether group in the side chain. Examples thereof include polyoxyalkylene ether polymer compounds. Specific examples of commercially available products include, for example, Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, Capstone FS-30, FS-31 (above, DuPont); PF-151N, PF-154N (above, manufactured by Omnova Co.); and the like.

The above ink composition is preferably used as a magenta ink. The ink composition may be used alone, or may be used as an inkjet recording ink set including a cyan ink composition, a yellow ink composition, and a black ink composition for the purpose of obtaining a full-color recorded image. Good. At this time, the colorants contained in the cyan, yellow, and black ink compositions are not particularly limited, and known pigments can be arbitrarily used. In addition to the four color ink set, four or more color inks in which each ink composition such as violet, orange-brown, and green is arbitrarily added for the purpose of obtaining a recorded image with a higher-definition hue. It may be a set.

The colorants that may be contained in each color ink composition for the purpose of obtaining a full-color recorded image are described below.
The colorant is preferably a pigment, and the pigment mainly includes an inorganic pigment, an organic pigment, and an extender pigment, and any pigment may be used. The pigments may be used alone or in combination.
The purpose of using the pigment in combination includes adjusting the hue. Examples of the adjustment of the hue include making the recorded image light and shade; widening the color gamut; and the like. Further, when a plurality of pigments are used in combination, the storage stability in the ink composition may be improved, and this may be the object.

Specific examples of the organic pigment contained in each of the cyan, yellow, black, violet, orange to brown, and green ink compositions include C.I. I. Pigment Blue 1, 2, 3, 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 22, 25, 60, 66, 80 and other cyan (blue) color pigments. C.I. I. Pigment Yellow 1, 2, 3, 12, 13, 14, 16, 17, 24, 55, 73, 74, 75, 83, 93, 94, 95, 97, 98, 108, 114, 120, 128, 129, 138, 139, 150, 151, 154, 155, 180, 185, 193, 199, 202, 213 and the like yellow pigments; C.I. I. Pigment Black 1 or the like; a black pigment; C.I. I. Pigment Violet 19, 23, 29, 37, 38, 50 and other violet pigments; C.I. I. Pigment Orange 13, 16, 68, 69, 71, 73 and other orange to brown pigments; C.I. I. Pigment Green 7, 36, 54 and the like; green pigments; and the like. Among these, the yellow pigment contained in the yellow ink composition includes C.I. I. Pigment Yellow 74, 151, and 155 are preferred. The cyan (blue) pigment contained in the cyan ink composition includes C.I. I. Pigment Blue 15:3 and at least one selected from 15:4 are preferable.

Examples of the inorganic pigment include carbon black, metal oxides, metal hydroxides, metal sulfides, metal ferrocyanides, metal chlorides and the like. Carbon black is particularly preferable as the pigment contained in the black ink composition. Examples of carbon black include thermal black, acetylene black, oil furnace black, gas furnace black, lamp black, gas black, channel black and the like. Among these, gas furnace black, lamp black, acetylene black, and channel black are preferable.

The carbon black is easily available as a commercial product. Specific examples thereof, Raven760ULTRA, Raven780ULTRA, Raven790ULTRA, Raven1060ULTRA, Raven1080ULTRA, Raven1170, Raven1190ULTRAII, Raven1200, Raven1250, Raven1255, Raven1500, Raven2000, Raven2500ULTRA, Raven3500, Raven5000ULTRAII, Raven5250, Raven5750, Raven7000 (or, Columbia Carbon Co. Ltd.); Monarch700, Monarch800, Monarch880, Monarch900, Monarch1000, Monarch1100, Monarch1300, Monarch1400, Regal1330R, Regal1400R, Regal1660R, MogulL (manufactured by Cabot Corporation); ColorBlackFW1, ColorBlackFW2, ColorBlackFW18, ColorBlackFW200, ColorBlackFW285, Printex35, PrintexU, PrintexV, Printex140U, Printex140V, SpecIalBlack4, SpecIalBlack4A, SpecIalBlack5, SpecialBlack6, Nerox305, Nerox505, Nerox510, Nerox605, Nerox600 (or, Orion engineered made of carbon, Inc.); MA7, MA8, MA100, MA600, MCF-88, No. 25, No. 33, No. 40, No. 47, No. 52, No. 900, No. 2300 (above, manufactured by Mitsubishi Chemical); and the like.

As the organic pigment, for example, soluble azo pigment, insoluble azo pigment, insoluble diazo pigment, condensed azo pigment, phthalocyanine pigment, quinacridone pigment, isoindolinone pigment, dioxazine pigment, perylene pigment, perinone pigment, thioindigo pigment, anthoraquinone pigment, quinophthalone. Examples include pigments.

Examples of extender pigments include silica, calcium carbonate, talc, clay, barium sulfate, and white carbon. These extender pigments are not used alone but are usually used in combination with an inorganic pigment or an organic pigment.

The total content of pigments in the total mass of each ink composition such as cyan, yellow, and black is usually 1 to 30%, preferably 1 to 10%, more preferably 2 to 7%.

From the viewpoint of safety and dischargeability, the above-mentioned colorant should contain as little as possible, for example, mutagenic synthetic raw materials, various metal salts such as calcium, other organic impurities, and by-products generated during synthesis. It is preferable to use.

Unless otherwise specified, the items common to all the ink compositions described above, including the ink compositions of the respective colors forming the ink set, will be described below.

The above ink composition is a composition in which a colorant is dispersed in the ink composition. For this reason, it is preferable to contain a dispersant for the purpose of making the colorant finer and preventing re-aggregation of the finely-divided colorant and improving dispersion stability as described later.

Examples of the dispersant include a nonionic dispersant, an anion dispersant, and a polymer dispersant, which can be appropriately selected according to the purpose. The dispersants may be used alone or in combination. Among these, at least one selected from the group consisting of nonionic dispersants and anionic dispersants is preferable.
It is generally known that some surfactants can be used as a dispersant.
The amount of the dispersant used is usually 1 to 60%, preferably 10 to 50%, and more preferably 2 to 40, based on the total mass of the pigment, as a mass ratio in terms of solid content when preparing a dispersion liquid. %. When it is 1% or more, the pigment can be sufficiently miniaturized, and when it is 60% or less, image bleeding, deterioration of water resistance, abrasion resistance and the like can be prevented.

Nonionic dispersants include polyoxyethylene alkyl ethers, polyoxyethylene alkylaryl ethers, polyoxyethylene polyoxypropylene glycols, glycerin esters, sorbitan esters, sucrose esters, glycerin ester polyoxyethylene ethers, sorbitan ester polyoxys. Ethylene ether, sorbitol ester polyoxyethylene ether, fatty acid alkanolamide, polyoxyethylene fatty acid amide, amine oxide, polyoxyethylene alkylamine, polyoxyethylene-β-naphthyl ether, polyoxyethylene styryl phenyl ether, polyoxyethylene disene Cylle phenyl ether and the like can be mentioned.

As the anionic dispersant, alkyl sulfates, alkyl ether sulfates, alkyl ester sulfates, alkyl aryl ether sulfates, alkyl sulfonates, sulfosuccinates, alkylaryl and alkylnaphthalene sulfonates, alkyl phosphates, Examples thereof include polyoxyethylene alkyl ether phosphate ester salt, alkyl allyl ether phosphate salt, polyoxyethylene alkyl ether sulfate salt, polyoxyethylene styryl phenyl ether sulfate salt, and polyoxyethylene distyryl phenyl ether sulfate salt.

Polymer dispersants include styrene and its derivatives; vinylnaphthalene and its derivatives; α,β-ethylenically unsaturated carboxylic acid aliphatic alcohol esters; acrylic acid and its derivatives; maleic acid and its derivatives; itaconic acid and its Derivatives; fumaric acid and its derivatives; vinyl acetate, vinyl alcohol, vinylpyrrolidone, acrylamide, and its derivatives; and at least two monomers (preferably at least one of them) Examples thereof include copolymers (block copolymers, random copolymers, graft copolymers) in which one is a hydrophilic monomer, and/or salts thereof. The above various copolymers and/or salts thereof may be used alone or in combination of two or more kinds.
The mass average molecular weight of the polymer dispersant is about 1,000 to 30,000, preferably 1,250 to 25,000, more preferably about 1,500 to 20,000. The acid value is about 80 to 300, preferably 90 to 275, more preferably about 100 to 250.
These dispersants may be used alone or in combination of two or more.
The dispersant can also be obtained as a commercial product, and specific examples thereof include Johncryl ^TM 61J, 67, 68, 450, 55, 555, 586, 678, 680, 682, manufactured by BASF. 683, 690; B-36; and the like.

As a method for preparing the ink composition, for example, a known method such as stirring and mixing the colorant with a sand mill (also called a bead mill), a roll mill, a ball mill, a paint shaker, an ultrasonic disperser, a microfluidizer, or the like is used. An aqueous dispersion of a colorant dispersed by using the above is prepared, a water-soluble organic solvent, water, and an ink preparation agent if necessary are added, and the mixture may be mixed by a known method using stirring, a homogenizer, or the like. The order of mixing the respective components of the ink composition is not particularly limited, but in order to reduce the aggregation action such as solvent shock, the water-soluble organic solvent and the ink preparation agent are dissolved in water and then the aqueous dispersion of the colorant is used. It is preferable to add a liquid.

When the above ink composition is used for inkjet recording, it is preferable to remove solid impurities other than the components necessary for the ink composition by, for example, filtration separation, centrifugation, or the like. As a method for separating by filtration, a known method can be appropriately used. At this time, the pore size of the filter is not particularly limited as long as it can remove coarse particles and dust, but is preferably 0.5 to 10 μm, more preferably 1 to 3 μm. The material of the filter is not particularly limited as long as it is suitable for water, but polypropylene and glass fiber are preferable from the viewpoint of cost and filtration efficiency. When performing filtration, the filters may be used alone or in combination of two or more, and two-stage filtration using two types of filters is preferable from the viewpoint of filtration accuracy.

Further, the above colorant may be used in a state of being covered with a dispersant, such as being microencapsulated with a dispersant or emulsified. Examples of such a method include the following chemical production methods, physical production methods, physicochemical methods, and mechanical production methods.
・Acidation method (Solubility in water is imparted by neutralizing at least a portion of the anionic groups of organic polymer compounds containing anionic groups with basic compounds, and kneading in an aqueous medium with coloring materials. After that, a method of neutralizing or acidifying with an acidic compound, precipitating organic compounds, fixing them to a coloring material, and then neutralizing and dispersing them);
Phase inversion emulsification method (a mixture containing an anionic organic polymer having a dispersibility in water and a coloring material is used as an organic solvent phase, and water is added to the organic solvent phase or the above organic solvent is added to water. Method of charging solvent phase);
Interfacial polymerization method (method in which two kinds of monomers or two kinds of reactants are separately dissolved in a dispersed phase and a continuous phase, and both substances are reacted at the interface between the two to form a wall film);
In-situ polymerization method (method in which a liquid or gas monomer and a catalyst, or two reactive substances are supplied from either the continuous phase core particle side to cause a reaction to form a wall film);
In-liquid curing coating method (method of forming a wall film by insolubilizing drops of a polymer solution containing core substance particles in a liquid with a curing agent);
-Coacervation (phase separation) method (method in which a polymer dispersion liquid in which core material particles are dispersed is separated into a coacervate (rich phase) having a high polymer concentration and a dilute phase to form a wall film);
In-liquid drying method (Preparation of a liquid in which the core substance is dispersed in a solution of the wall membrane substance, and the dispersion liquid is put in a liquid in which the continuous phase of the dispersion liquid is immiscible to dissolve the wall membrane substance. Method to form a wall film by gradually removing the existing medium);
・Melting dispersion cooling method (using a wall film substance that melts into a liquid when heated and solidifies at room temperature, this substance is heated and liquefied, and core substance particles are dispersed in it, cooled into fine particles and cooled Method of forming a film);
・Air suspension coating method (a method of forming a wall film by suspending powder core substance particles in the air by a fluidized bed, and spraying and mixing the coating liquid of the wall film substance while floating in the air flow) ;
・Spray drying method (a method of spraying an encapsulating stock solution and bringing it into contact with hot air to evaporate and dry volatile components to form a wall film)
And the like, and particularly those used for inkjet are the phase inversion emulsification method, the acid precipitation method, and the interfacial polymerization method.
The content ratio of the dispersant to the total mass of the colorant in the ink composition is usually 20 to 150%, preferably 30 to 80%.

Instead of dispersing the colorant using the above dispersant, a so-called surface-treated pigment (self-dispersion pigment) in which a dispersibility-imparting group is chemically introduced directly to the surface of the colorant may be used as the colorant. ..

The average particle diameter (D50) of the colorant in the dispersion of the colored body obtained as described above is usually 200 nm or less, preferably 50 to 200 nm, more preferably 70 to 70 from the viewpoint of storage stability and dischargeability. 170 nm, and more preferably 80 to 130 nm.
Further, in some cases, in addition to D50, it is also preferable to measure D90 and D10 of the colorant.
The D90 (the cumulative 90% value calculated from the small particle side in the frequency distribution of scattering intensity) of the colorant particles is usually 300 nm or less, preferably from the viewpoint of reducing coarse particles and increasing the storage stability of the dispersion. It is 250 nm or less, more preferably 200 nm or less. The lower limit is preferably 100 nm or more from the viewpoint of easy production.
D10 (a cumulative 10% value calculated from the small particle side in the frequency distribution of the scattering intensity) of the pigment particles is usually 10 nm or more, preferably from the viewpoint of print density when the ink composition is used and from the ease of production. Is 20 nm or more, and more preferably 30 nm or more and 50 nm or less.

The colorant dispersion and water used for preparing the ink composition are, for example, distilled water, ion-exchanged water, pure water, ultrapure water, or the like and have a pH of 6.5 to 7.5 and various types of water. Water that does not contain free ions such as metal ions is preferred.

Examples of the ink preparation agent include antiseptic and antifungal agents, pH adjusters, chelating agents, rust inhibitors, water-soluble ultraviolet absorbers, antioxidants, water-soluble polymers, water-dispersible polymers, defoamers, The above-mentioned surfactants and the like can be mentioned. These ink adjusting agents will be described below.

Specific examples of the fungicide include sodium dehydroacetate, sodium benzoate, sodium pyridinethione-1-oxide, p-hydroxybenzoic acid ethyl ester, 1,2-benzisothiazolin-3-one and salts thereof. ..

Specific examples of the preservatives include, for example, organic sulfur type, organic nitrogen sulfur type, organic halogen type, haloaryl sulfone type, iodopropargyl type, haloalkylthio type, nitrile type, pyridine type, 8-oxyquinoline type, benzo Thiazole type, isothiazoline type, dithiol type, pyridine oxide type, nitropropane type, organotin type, phenol type, quaternary ammonium salt type, triazine type, thiazine type, anilide type, adamantane type, dithiocarbamate type, brominated indanone type , Benzyl bromoacetate-based compounds, inorganic salt-based compounds and the like.
Specific examples of the organic halogen-based compound include sodium pentachlorophenol.
Specific examples of the pyridine oxide-based compound include 2-pyridinethiol-1-oxide sodium.
Specific examples of isothiazoline compounds include, for example, 1,2-benzisothiazolin-3-one, 2-n-octyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one. On, 5-chloro-2-methyl-4-isothiazolin-3-one magnesium chloride, 5-chloro-2-methyl-4-isothiazolin-3-one calcium chloride, 2-methyl-4-isothiazolin-3-one calcium Examples thereof include chloride.
Specific examples of the other antiseptic/antifungal agents include anhydrous sodium acetate, sodium sorbate, sodium benzoate, manufactured by Arch Chemical Co., trade name Proxel ^TM GXL(S), Proxel ^TM LV, Proxel ^TM XL-2(S) and the like. Are listed.

Specific examples of the pH adjuster include, for example, alkanolamines such as diethanolamine, triethanolamine and N-methyldiethanolamine; hydroxides of alkali metals such as lithium hydroxide, sodium hydroxide and potassium hydroxide; ammonium hydroxide ( Ammonia water); carbonates of alkali metals such as lithium carbonate, sodium carbonate, sodium hydrogen carbonate and potassium carbonate; alkali metal salts of organic acids such as sodium silicate and potassium acetate; inorganic bases such as disodium phosphate. To be

Specific examples of the chelating agent include disodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, sodium uracildiacetate, and the like.

Specific examples of the rust preventive include acid sulfite, sodium thiosulfate, ammonium thioglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, dicyclohexylammonium nitrite and the like.

Specific examples of the water-soluble ultraviolet absorber include sulfonated benzophenone compounds, benzotriazole compounds, salicylic acid compounds, cinnamic acid compounds, and triazine compounds.

The water-soluble polymer compound is not particularly limited as long as it is a polymer that dissolves in water, but an anionic polymer and a nonionic polymer are preferable from the viewpoint of dispersion stability. Specific examples of the anionic polymer include cellulose derivatives such as carboxymethyl cellulose, acrylic acid derivatives such as polyacrylic acid, and polystyrene derivatives such as polystyrene sulfonate. Specific examples of the nonionic polymer include polyethylene glycol, polyvinyl alcohol, polyvinylpyrrolidone, gelatin and the like.

The water-dispersible resin has a function of fixing the colorant in the ink 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 resin, polyester resin, acrylic resin, vinyl acetate resin, vinyl chloride resin, acrylic styrene resin, acrylic silicone resin, styrene. Butadiene-based resins and the like can be mentioned.
The water-dispersible resin is used, for example, in the state of a resin emulsion dispersed in water as a continuous phase.
Some resin emulsions are commercially available. Specific examples thereof include Superflex ^TM 126, 130, 150, 170, 210, 420, 470, 820, 830, 890 (urethane resin emulsion, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.); Hydran ^TM HW-350, HW-178, HW-163, HW-171, AP-20, AP-30, WLS-201, WLS-210 (urethane resin emulsion, manufactured by DIC); 0569, 0850Z, 2108 (styrene-butadiene resin emulsion). , Manufactured by JSR); AE980, AE981A, AE982, AE986B, AE104 (acrylic resin emulsion, manufactured by Etec); and the like.
When a water-dispersible resin is used, the content of the water-dispersible resin in the total mass of the ink composition is usually 0.5 to 20%, preferably 1 to 15%, more preferably 2 in terms of solid content. -10%. When it is 0.5% or more, it becomes easy to obtain a sufficient fixing property to the recording material, and when it is 20% or less, there is no possibility of hindering normal ejection of ink droplets in inkjet recording. ..

As specific examples of the antioxidant, for example, various organic and metal complex-based fading inhibitors can be used. Examples of the organic anti-fading agent include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromanes, alkoxyanilines, and heterocycles. ..

Specific examples of the defoaming agent include silicone type, silica mineral oil type, olefin type and acetylene type. Examples of commercially available antifoaming agents include Surfynol ^TM DF37, DF58, DF110D, DF220, MD-20 and Olfine ^TM SK-14, all manufactured by Shin-Etsu Chemical Co., Ltd. These antifoaming agents may be used alone or in combination of two or more kinds.
The addition amount of the defoaming agent is preferably 0.01 to 5%, more preferably 0.03 to 3%, further preferably 0.05 to 1%. When it is 0.01% or more, the effect as an antifoaming agent becomes good, and when it is 5% or less, the dispersion stability becomes good.

When the above ink composition is used as an ink for ink jet recording, the ink composition has a low content of inorganic impurities such as chloride of metal cations (eg sodium chloride) and sulfate (eg sodium sulfate). Is preferably used. The standard of the content of the inorganic impurities is about 1% or less with respect to the total mass of the dye, and the lower limit may be the detection limit of the analytical instrument, that is, 0%.
Inorganic impurities are often mixed in the colorant. Therefore, if necessary, for example, a dried product of the colorant or a wet cake is stirred in a mixed solvent of a (C1-C4) alcohol such as methanol and water, the precipitate is separated by filtration, and dried. After forming the ink composition, the impurities may be removed by a method of exchanging and adsorbing the inorganic impurities with the ion exchange resin.

The pH of the ink composition is adjusted to pH 7 to 11, and more preferably pH 8 to 10 for the purpose of improving storage stability and compatibility with inkjet printer members.
The surface tension of the ink composition is usually 10 to 50 mN/m, preferably 20 to 40 mN/m. Further, the viscosity of the ink composition is usually 2 mPa·s or more and 30 mPa·s or less, and preferably 3 mPa·s or more and 20 mPa·s or less.
The pH and surface tension of the ink composition can be appropriately adjusted with the above-mentioned pH adjuster, surfactant, water-soluble organic solvent and the like.

The ink composition can be used in various recordings. For example, it is suitable for writing instruments, aqueous printing, information recording, printing, etc., and particularly preferably used for inkjet recording.

In the inkjet recording method, recording is performed by using the ink composition or each ink composition of the ink set as an ink, ejecting droplets of the ink according to a recording signal, and attaching the droplets to a recording material. Is the way to do it. The ink nozzles and the like used during recording are not particularly limited and can be appropriately selected according to the purpose.

The inkjet method may be any known method. For example, a charge control method that discharges ink by using electrostatic attraction; a drop-on-demand method (pressure pulse method) that uses the oscillating pressure of a piezo element; an electric signal is converted into an acoustic beam, and the ink is irradiated and emitted. Examples thereof include an acoustic inkjet method of ejecting ink using pressure; a thermal inkjet method of heating ink to form bubbles and utilizing generated pressure; that is, a bubble jet (registered trademark) method.
The inkjet method is a method of ejecting a large number of inks having a small content of a coloring agent in the ink, which is called a photo ink, in a small volume; the hues are substantially the same and the concentration of the coloring agent in the ink is different. A method of improving the image quality by using a plurality of inks; a method of improving the fixability of the colorant by using a colorless transparent ink are also included.

The above-mentioned recording material is not particularly limited as long as it is a substance colored by the above-mentioned ink composition, and examples thereof include: information transmission sheets such as paper and film, fibers and cloths (cellulose, nylon, wool, etc.), Examples include leather and base materials for color filters. Among these, the information transmission sheet is preferable.

The information transmission sheet can be roughly classified into a sheet having an ink receiving layer and a sheet having no ink receiving layer.

Examples of the material having an ink receiving layer include paper, synthetic paper, film and the like as a base material, and an ink receiving layer provided on the base material. The ink receiving layer is formed, for example, by impregnating or coating a cationic polymer on the above base material; inorganic fine particles such as porous silica, alumina sol, special ceramics, etc., together with a hydrophilic polymer such as polyvinyl alcohol or polyvinyl pyrrolidone, on the surface of the base material. And the like.
The information transmission sheet having the ink receiving layer is usually called; inkjet dedicated paper, inkjet dedicated film, glossy paper, or the like. Typical examples of commercially available products are: Canon Co., Ltd. product name: Professional Photo Paper, Super Photo Paper, Glossy Gold and Matte Photo Paper; Seiko Epson Co. product name: Photo Paper Crispear (High Gloss), photo paper (gloss), photo matte paper; Hewlett-Packard Co., Ltd. product name: Advanced Photo Paper (gloss); Fuji Film Co., Ltd. product name: Picture Photo Finish Pro; Can be mentioned.

Examples of the information transmission sheet having no ink receiving layer include various types of paper such as coated paper and art paper used for gravure printing, offset printing, etc.; cast coated paper used for label printing, etc. ..
When an information transmission sheet having no ink receiving layer is used as a recording material, it is also preferable to subject the recording material to a surface modification treatment for the purpose of improving the fixing property of the colorant.

As the surface modification treatment, it is preferable to perform at least one kind of treatment selected from corona discharge treatment, plasma treatment, and flame treatment. Any known method may be used for these treatments. Further, it is generally known that the effects of these treatments are attenuated over time. For this reason, when the information transmission sheet is subjected to the surface modification treatment, it is preferable to continuously perform inkjet recording without waiting time.

Examples of the corona discharge treatment include a method in which a high voltage of several thousand volts is applied between a grounded metal roll and a wire-shaped electrode placed at an interval of several mm to generate corona discharge. By disposing an information transmission sheet between the electrode and the roll during the corona discharge and treating the sheet, the surface of the sheet is made hydrophilic.

As the plasma treatment, the information transmission sheet is placed in a container containing argon, neon, helium, nitrogen, nitrogen dioxide, oxygen, air, etc., and exposed to plasma generated by glow discharge, so that the surface of the sheet is oxygen, nitrogen. Examples of the method include introducing a functional group containing

The flame treatment is also called flame treatment, and for example, there is a method of spraying a gas oxidizing flame or the like injected from a burner or the like on the surface of the information transmission sheet to oxidize the surface of the sheet to improve hydrophilicity.

The surface modification treatment can be performed by appropriately adjusting the number of treatments, the treatment time, the applied voltage, etc. so that a desired effect can be obtained.

When recording on a recording material by the above-mentioned inkjet recording method, at least the above-mentioned ink composition is used as magenta ink, a container containing this is loaded at a predetermined position of an inkjet printer, and recording is performed by the above-mentioned recording method. Record it on the material.
Further, when performing ink jet recording using the above ink set, each container containing the ink composition of each color may be loaded at a predetermined position of the ink jet printer and recorded on the recording material by the above recording method. ..

The above-mentioned colored body means a substance colored with the above-mentioned ink composition or an ink set containing the same, and preferably a recording material colored by the above-mentioned inkjet recording method.

According to the present invention, it is possible to provide an ink composition, in particular, a magenta ink composition for use in inkjet, which has improved color development, light resistance, red color reproduction range, and storage stability comprehensively. In addition, the ink set, the inkjet recording method, and the colored body using the ink composition of the present invention as a magenta ink composition are excellent in fading balance with ink compositions of other colors other than the yellow ink composition, and may be aged. Image deterioration can be improved.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to the following Examples. The following Example 1 shall be read as Reference Example 1.
The solid content in the dispersion solution was determined by a dry weight method using MS-70 manufactured by A&D Co., Ltd.

(A) Preparation of dispersion [Preparation example 1]
John Cryl 68 (25 parts), triethanolamine (13.3 parts), and ion-exchanged water (61.7 parts) were added to a three-necked flask equipped with a cooling tube, and the temperature was raised to 90°C with stirring at 150 rpm. The solution was heated to obtain an aqueous solution containing 25% of John Cryl 68.
"John Kryl 68" in Table 1 below means an aqueous solution containing 25% of this John Kryl 68.

(B) Preparation of Aqueous Dispersion [Preparation Example 2]: Preparation of Red Dispersion (1)
PR122 (Inkjet Magenta E02VP2621 manufactured by Clariant Co., Ltd.) was used as a di-substituted quinacridone red pigment, and the components shown in Table 1 below were mixed and dispersed for 15 hours under a sand grinder at 1500 rpm. The obtained liquid was diluted with ion-exchanged water, the beads for dispersion were separated by filtration, and the red dispersion liquid was prepared by adjusting the content of the colorant to 15% with ion-exchanged water. This dispersion is referred to as "dispersion 1".
The pH of Dispersion 1 was 7.7, the average particle diameter of the colorant was 77 nm, and the viscosity was 5.4 mPa·s.
In addition, in Tables 1 and 2 below, all the numerical values indicating the amounts of the components are “parts”, and “−” means that the component is not included. Moreover, the "water" used the ion exchange water. Further, "Olfin SK-14" is an antifoaming agent and is not contained in the ink compositions of the respective Examples and Comparative Examples because it is removed by filtration.

[Preparation Examples 3 and 4]: Preparation of Red Dispersion Liquids (2) to (3)
Dispersions 2 and 3 were obtained in the same manner as in Preparation Example 2 except that the components used in Preparation Example 2 and the amounts thereof used were changed to the components shown in Table 1 below and the amounts used. ..

[Examples 1 to 5]: Preparation of ink of the present invention Using Dispersions 1 and 2 prepared as described above, mixed with each component shown in Table 2 below, and then a contaminant was filtered through a 3 µm membrane filter. Were filtered off to obtain the ink compositions of Examples 1 to 5 of the invention for the evaluation test.
Abbreviations and the like in Table 2 have the following meanings.
GLY: glycerin DEG: diethylene glycol 2-PY: 2-pyrrolidone DGMBE: diethylene glycol monobutyl ether NE-15: Hitenol ^TM NE-15
GXL(s): Proxel ^TM GXL(s)
In addition, "PR122 (%)" in Table 2 means "content of PR122 (mass %)" in the total mass of the colorant contained in each ink composition.

[Comparative Examples 1 to 5]: Preparation of ink for comparison Dispersions 1 and 3 prepared as described above were used, mixed with each component described in Table 2 above, and then mixed with a 3 μm membrane filter. Were filtered off to obtain comparative ink compositions of Comparative Examples 1 to 5.

[Evaluation test]
The ink compositions of Examples and Comparative Examples obtained as described above were subjected to the evaluation tests (A) to (C) below.

[(A) Storage stability test]
Regarding the average particle diameter (D50) and viscosity measured by the following method, the rate of change of each measured value immediately after preparation and after storage at 60°C for 10 days was calculated by the following formula, and evaluated according to the following four-stage criteria. did.
The smaller the difference between the measured value immediately after preparation and the measured value after storage for 10 days, the better the stability is, and the better the storage stability is. In addition, the index with the lowest evaluation was used for the overall judgment of storage stability. The results are shown in Table 3 below.
Change rate of physical property value=(measured value after storage−measured value immediately after preparation)/(measured value immediately after preparation)×100%
A: Change rate is less than ±5% B: Change rate is ±5% or more, less than ±8% C: Change rate is ±8% or more, less than ±15% D: Change rate is ±15% or more, ±20% Less than

[Measurement of average particle diameter (D) 50]
For the ink compositions of each Example and Comparative Example,
1. Immediately after preparation, and
2. After storing in a closed container at 60°C for 10 days,
Each of the two types of samples was diluted with ion-exchanged water so that the concentration of the dye component was 0.02%, to prepare each test solution for measuring the average particle size. The average particle diameter (D50) of each of the obtained test liquids was measured.
A dynamic light scattering particle size distribution analyzer LB-500 (manufactured by Horiba Ltd.) was used to measure the average particle diameter (D50).

[Measurement of viscosity]
For the ink compositions of each Example and Comparative Example,
1. Immediately after preparation, and
2. After storing in a closed container at 60°C for 10 days,
The viscosity at 25° C. was measured twice.
An E-type viscometer RE105L (manufactured by Toki Sangyo Co., Ltd.) was used for measuring the viscosity.

[(B) Redispersibility test]
The ink composition of each Example and Comparative Example (25 μL each) was placed on a glass petri dish and dried for 1 hour in a thermo-hygrostat at 60° C. To each ink composition after drying, 10 mL of ion-exchanged water was added dropwise at room temperature, and whether or not redispersion was performed was visually evaluated according to the following four-stage criteria. The redispersed ink is more excellent because it is easier to eliminate clogging after drying. The results are shown in Table 3 below.
A: All are redispersed without any residue.
B: A small amount of residue remains, but most of it is redispersed.
C: A lot of residue remains, but it is redispersed to some extent.
D: No redispersion at all.

[(C) Filterability test]
The ink composition of each Example and Comparative Example (each 100 mL) was filtered through a membrane filter (material: mixed cellulose ester, manufactured by Advantech, pore size 1 μm), the filtration time was measured, and evaluated according to the following three evaluation criteria. did. The shorter the filtration time is, the better because the filter and nozzles mounted on the inkjet printer do not become clogged and the ejection stability is high. The results are shown in Table 3 below.
A: Less than 60 seconds B: 60 seconds or more, less than 120 seconds C: 120 seconds or more

In all of the storage stability, redispersibility, and filterability, each example showed better results than Comparative Examples 2-4. In addition, Comparative Example 1 showed excellent results in these tests as in each Example.
Furthermore, in consideration of redispersibility, it has been found that the upper limit of the content of PR122 in the total mass of the colorant is preferably about 80%.

[Inkjet recording]
Each ink composition obtained in each of the examples and comparative examples was filled in an ink jet printer manufactured by Seiko Epson Co., Ltd. and a magenta cartridge having a trade name of PX101, and ink jet recording was performed on Zigler quality paper Z-Plot650.
Inkjet recording was performed so that a solid image with 100% duty was obtained, and a recorded image recorded with the ink composition of each Example or Comparative Example was obtained. Using this as a test piece, the following evaluation tests (D) to (G) were performed.
The color measurement of each test piece obtained as described above was performed using a colorimeter manufactured by X-rite, trade name: SpectroEye™. The colorimetric conditions are ANSIA as a density standard, a viewing angle of 2°, and a light source D50.

[(D) Color development test]
The reflection density Dm value (OD value) of each test piece obtained as described above was color-measured and evaluated according to the following three-step evaluation criteria. The results are shown in Table 4 below. The larger the obtained OD value is, the higher the coloring property is, which is excellent.
A: OD value is 1.0 or more B: OD value is 0.9 or more and less than 1.0 C: OD value is less than 0.9

[(E) Saturation test]
The L ^* a ^* b ^* of each test piece obtained as described above was measured for color to calculate a C ^* value, and evaluated according to the following four-step evaluation criteria. The results are shown in Table 4 below. The larger the obtained C ^* value, the more vivid the color is, which is excellent.
A: C ^* value is 65.5 or more B: C ^* value is 65.0 or more and less than 65.5 C: C ^* value is 64.5 or more and less than 65.0 D: C ^* value is less than 64.5

[(F) Light resistance test]
After each test piece obtained as described above was exposed for 2 weeks under the conditions of a temperature of 24° C., a humidity of 60% and an illuminance of 100 kLux using a light resistance tester (Xenon weather meter manufactured by Suga Test Instruments Co., Ltd.) The residual ratio of the colorant before and after the test was measured, and evaluated according to the following four-level evaluation criteria. The results are shown in Table 4 below.
A: Residual rate is 90% or more and less than 95% B: Residual rate is 80% or more and less than 90% C: Residual rate is less than 80%

From the results in Table 4, it was found that Comparative Examples 1 and 2 were as excellent as Examples 1 and 2 in terms of the balance of color developability, saturation, and light resistance. However, it was confirmed that Examples 3 to 5 were superior to Comparative Examples 1 and 2 at the same level or higher.
Therefore, considering the results of Table 3 above, it was confirmed that the upper limit of the content of PR122 in the total mass of the colorant is particularly preferably about 70%.

[Preparation Example 5]: Preparation of red dispersion liquid (4)
The block copolymer described in Synthesis Example 3 of WO 2013/115071 was prepared, and 6 parts of the obtained polymer dispersant was dissolved in 30 parts of 2-butanone to form a uniform solution. To this solution, a solution prepared by dissolving 0.44 parts of sodium hydroxide in 41 parts of ion-exchanged water was added and stirred for 1 hour to prepare an emulsified solution. At this time, no crystals were precipitated. C. I. Pigment Red 122 (Inkjet Magenta E02VP2621 manufactured by Clariant) was added thereto, and the mixture was dispersed with a sand grinder. The dispersion was performed for 15 hours under the condition of 1500 rpm. Then, 100 parts of ion-exchanged water was added dropwise, the dispersion beads were removed by filtration, and then 2-butanone and water were distilled off under reduced pressure with an evaporator to obtain a red dispersion liquid having a pigment solid content of 11.92%. It was The solid content in the aqueous solution was measured by a dry weight method using MS-70 manufactured by A&D Co., Ltd. At this time, pH was 8.6 and the average particle size of the pigment was 109 nm. The resulting colored dispersion is designated as Dispersion 4.

[Preparation Example 6]: Preparation of red dispersion liquid (5)
Pigment C.I. used in Preparation Example 5 above. I. Pigment Red 122 instead of C.I. I. A red dispersion liquid was obtained in the same manner as in Preparation Example 5 except that Pigment Red 150 was used. The pigment solid content of the dispersion was 11.16%, the pH was 7.9, the average particle diameter of the pigment was 100 nm, and the viscosity was 2.4 mPa·s. The obtained colored dispersion is designated as Dispersion 5.

[Examples 6 and 7]: Preparation of ink of the present invention Using Dispersions 4 and 5 prepared as described above, mixed with each component described in Table 5 below, and then a contaminant was filtered through a 3 μm membrane filter. Were filtered off to obtain the ink compositions of Examples 6 and 7 of the present invention for the evaluation test. In Table 5 below, the numerical value of each component means the number of copies.

Using the ink compositions of Examples 6 and 7 obtained as described above, "inkjet recording" is performed in the same manner as above, and "(D) color development test" and "(E) saturation test" are performed. Therefore, the performance was evaluated. As a result, it was confirmed that the results of the "(D) color development test" of the ink compositions of Examples 6 and 7 were all A, and the results of the "(E) Saturation test" were all C. It was

The ink composition of the present invention is excellent in storage stability, redispersibility, and filterability, and has a good balance of color developability, saturation, and light resistance, and is therefore extremely useful as a magenta ink for inkjet recording. ..

Claims (21)

As a colorant, C.I. I. Pigment Red 150 and C.I. I. Containing a quinacridone pigment selected from pigment and water,
The quinacridone pigment is C.I. I. It is a Pigment Red 122,
C. in the total mass of the colorant. I. Pigment Red 150 and the content ratio of the quinacridone pigment are 50/50 to 20/80 on a mass basis,
A colored dispersion liquid in which the average particle diameter of the colorant is 50 to 200 nm. An ink composition for inkjet recording, comprising the colored dispersion according to claim 1 and a water-soluble organic solvent. The ink composition according to claim 2 , wherein the total content of the colorant contained in the ink composition is 0.5 to 7% by mass based on the total mass of the ink composition. The ink composition according to claim 2 or 3 , wherein the water-soluble organic solvent is at least one selected from the group consisting of glycol ethers and alkanediols. The glycol ether is selected from ethylene glycol monoallyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monohexyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monobutyl ether, and propylene glycol monopropyl ether. The ink composition according to claim 4 , which is at least one selected from the group consisting of: The alkanediol is 1,2-pentanediol, 1,2-hexanediol, 2-methyl-2,4-pentanediol, 2-ethyl-1,3-hexanediol, and 2,4-diethyl-1, is at least one selected from the group consisting of 5-pentanediol, the ink composition according to claim 4 or 5. The ink composition according to any one of claims 2 to 6 , further comprising a surfactant. The ink composition according to claim 7 , wherein the surfactant is at least one selected from the group consisting of an anionic surfactant and a nonionic surfactant. The ink according to claim 8 , wherein the anionic surfactant is at least one selected from the group consisting of polyoxyethylene dinonyl phenyl ether sulfate, polyoxyethylene lauryl ether sulfate, and dioctyl sulfosuccinate. Composition. Said nonionic surfactant is at least one kind selected polyoxyethylene acetylene glycol ether, polyoxyethylene distyrenated phenyl ether, and from the group consisting of polyoxyethylene tribenzyl phenyl ether, claim 8 or 9 The ink composition according to item 1. An inkjet recording ink set comprising a magenta ink composition, a cyan ink composition, a yellow ink composition, and a black ink composition,
An ink set used for inkjet recording, wherein the magenta ink composition is the ink composition according to any one of claims 2 to 10 . The yellow ink composition is C.I. I. Pigment Yellow 74, C.I. I. Pigment Yellow 151, and C.I. I. The ink set according to claim 11, which contains at least one kind selected from the group consisting of Pigment Yellow 155 as a colorant. The cyan ink composition is C.I. I. Pigment Blue 15:3 and C.I. I. Pigment Blue 15:4 is contained, The ink set of Claim 11 or 12 containing at least 1 sort(s) as a coloring agent. An ink jet recording method, wherein droplets of the ink composition according to any one of claims 2 to 10 are ejected according to a recording signal and adhered to a recording material to perform recording. The inkjet recording method according to claim 14 , wherein the recording material is an information transmission sheet. The inkjet recording method according to claim 15 , wherein the information transmission sheet is a sheet having an ink receiving layer containing a porous white inorganic substance. The inkjet recording method according to claim 15 , wherein the information transmission sheet is cast coated paper. The inkjet recording method according to claim 15 , wherein the information transmission sheet is coated paper or art paper. The communication sheet is corona discharge treatment, a sheet in which at least one surface modification treatment is performed chosen from the plasma treatment, and flame treatment, an ink jet recording method according to claim 17 or 18. A colored body colored with the ink composition according to any one of claims 2 to 10 . An ink jet printer loaded with a container containing the ink composition according to any one of claims 2 to 10 .