JP2019157050A - Aqueous ink and printed matter using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-based ink which is excellent in ejection property and water resistance and can maintain stability by using a fine pigment having reduced coarse particles and easily dispersable as a specific solvent. There is something in it. The problem is a pigment (A) whose surface is coated with a resin, wherein the resin is an α-olefin copolymer having an acidic group, and the pigment (A) is adsorbed by the resin. The problem is solved by using a pigment (A) whose amount is 10% by mass or more and 50% by mass or less with respect to the uncoated pigment (B) and using an alcohol alkyl ether as a water-soluble solvent. [Selection diagram] None

Description

  The present invention relates to a water-based ink using a pigment dispersion coated with a resin, and use thereof.

  Pigment compositions that use organic pigments as pigments and coloring materials are used in paints such as automobiles and building materials, indoors and outdoors, printing inks such as offset inks, gravure inks, flexo inks, silk screen inks, and toners, and ink jet recording. It is used in various applications such as the ink field, color resists for color filters, paints, and stationery. Particularly in fields requiring high functionality, such as the paint field, ink jet recording field, color filter color resist field, and toner field, which require design, finer pigments are required than general-purpose pigments. It is essential that the dispersion after dispersing the pigment has very few coarse particles such as undispersed material.

  Examples of a method for obtaining a fine organic pigment include salt milling. Salt milling is a process in which the pigment is mechanically kneaded with a water-insoluble synthetic resin, a water-soluble inorganic salt such as salt, and a water-soluble organic solvent and a kneader. Thereafter, the water-soluble inorganic salt and the water-soluble organic are washed by washing with water. There is a method for removing the solvent (for example, Patent Documents 1 to 3). In this method, since the primary particle pulverization and crystal growth occur in parallel with each other, an organic pigment having an extremely small average particle diameter is finally obtained.

  The method is an excellent method for obtaining a fine organic pigment. However, since the target pigment is fine, aggregation between the pigments is extremely strong, and it is difficult to disperse the pigment to the primary particles in the subsequent process of obtaining the pigment dispersion, and a dispersion process in which a great deal of energy is input. Is required. Therefore, aggregation of pigments is suppressed by covering the pigment with a water-insoluble synthetic resin simultaneously with the pulverization of the pigment into primary particles. Unlike a dispersion process using a bead mill or the like generally used for pigment dispersion, this coating is uniform and strong and difficult to desorb. However, when the amount and type of the water-insoluble synthetic resin to be used are not appropriate, the coating of the pigment is insufficient, and the coarse particles cannot be reduced due to aggregation of the resins processed into the pigment. In particular, when a resin having a high Tg, such as an acrylic resin or a resin containing an aromatic resin, is used alone, the tendency is remarkable. Therefore, the primary particles of the pigment are crushed by an excessive dispersion process for dispersing the coarse particles, which causes problems such as an increase in viscosity and poor storage stability.

  Moreover, in order to remove coarse particles, when a fine filter filter is used, a filtration process that requires a large load is essential. These coarse particles are known to cause nozzle clogging in an ink jet head in the case of ink jet recording inks, which is a fatal problem. In particular, recent inkjet printers are rapidly increasing in resolution with the target image quality of existing printing technologies such as offset printing. Along with this, the density of the nozzles of the ink jet head and the miniaturization of the droplets have progressed, and the miniaturization and high integration of the nozzle diameter for ejecting ink have progressed (for example, Patent Document 4). As the size of the nozzle is reduced, the allowable size of the foreign matter is reduced, and the ink containing a large amount of coarse particles causes nozzle clogging. Therefore, there is a problem that it cannot be applied to a high-resolution ink jet printer unless an ink from which coarse particles are removed is provided.

 In general, the drying mechanism of water-based inkjet inks is classified into penetration and evaporation into the substrate after the ink has landed on the substrate, but the contribution of penetration is very large. Substrates with high hydrophobicity such as vinyl sheets and films have slow ink penetration, so in the case of multicolor printing, it is difficult to form appropriate dots to form clean images by mixing ink colors. There were problems such as being unable to raise. For this reason, it is necessary to control the wettability with respect to a base material, drying property, and permeability by adding a water-soluble solvent into the ink (for example, Patent Document 5). However, the addition of a penetrating solvent into the ink changes the dissolution state of the dispersion resin that stabilizes the pigment dispersion state, significantly lowers the storage stability of the pigment dispersion state, and causes pigment aggregation and viscosity increase. There was a case to wake up. In recent years, there has been a tendency to add a relatively strong hydrophobic solvent among water-soluble solvents, and it has been difficult to ensure more pigment dispersibility and storage stability. That is, it has been desired to provide a pigment dispersion that does not lower the pigment dispersibility even in the presence of a highly penetrating solvent.

 Furthermore, it is particularly difficult to obtain storage stability in the case of a yellow pigment that often contains a structure that is easily soluble in a water-soluble solvent such as an azo pigment. Further, the stabilization of the yellow pigment may include a co-coupler as a stabilizer. Since this co-coupler often has a red hue, there is a problem that the yellow hue deteriorates. Therefore, it is strongly desired to provide a water-based ink that can be stabilized without including a co-coupler and that is suitable for yellow ink using a solvent having high dischargeability and high permeability.

Japanese Patent Laid-Open No. 05-043704 Japanese Patent Laid-Open No. 7-13016 JP 2009-144126 A JP2013-993A JP 2004-315673 A

The subject of this invention is providing the water-based ink suitable for the water-soluble inkjet ink which is excellent in discharge property and water resistance, and can maintain stability.

That is, the present invention includes a pigment whose surface is coated with a resin, a water-soluble organic solvent, a basic substance (except for the case of the resin), and water,
The resin is an α-olefin copolymer having an acidic group,
The water-soluble organic solvent is an alcohol alkyl ether.

  The present invention also relates to the above water-based ink, wherein the resin is an α-olefin copolymer having a graft chain and an acidic group.

Moreover, this invention relates to the said water-based ink in which the said graft chain contains the partial structure selected from the group which consists of a structure shown by following General formula (1)-(3).
General formula (1)

[In General Formula (1), R ₁ represents a substituted C _{6 to} C ₃₀ alkyl group, an optionally substituted alicyclic structure, or an optionally substituted phenyl group]
General formula (2)

[In General Formula (2), R ₁ and R ₂ are each independently a hydrogen atom, an optionally substituted C ₁ -C ₃₀ alkyl group, an optionally substituted alicyclic structure, or a substituted group. Represents an optionally substituted phenyl group. However, when _one of R ₁ and R ₂ is a hydrogen atom, the other is not a hydrogen atom. ]
General formula (3)

[In General Formula (3), R ₁ represents a hydrogen atom, an alkyl group having 6 to 20 carbon atoms, or a phenyl group optionally substituted with an alkyl group having 1 to 9 carbon atoms, and A ¹ O and A ² O independently represents an alkyleneoxy group having 1 to 6 carbon atoms, m and n represent an average addition mole number of the alkyleneoxy group, each independently represents an integer of 0 to 100, and m + n is 1 or more. ]

  Moreover, this invention relates to the said water-based ink whose said resin coating amount of the said pigment is 10 to 50 mass parts with respect to 100 mass parts of pigments (B) before coating.

  Moreover, this invention relates to the said water-based ink whose said pigment is an azo pigment.

  Moreover, this invention relates to the said water-based ink which contains a crosslinking agent further.

Moreover, this invention relates to printed matter provided with the film containing the said water-based ink.

According to the present invention, a pigment can be uniformly dispersed and a water-based ink that is excellent in transparency, design, color reproducibility, and color rendering can be obtained. The aqueous pigment dispersion of the present invention can be used in various applications such as inkjet ink, flexographic ink, paint, gravure ink, silk screen ink, and stationery. More preferably, it is used as an inkjet ink.

<Pigment (A)>
The pigment (A) of the present invention has a surface coated with a resin, and the resin is an α-olefin copolymer having an acidic group, and the resin coating amount of the pigment (A): resin adsorption The amount is preferably 10% by mass or more and 50% by mass or less based on the uncoated pigment (B).
By the above, it is possible to provide a fine pigment that can be easily dispersed with reduced coarse particles. Further, in the aqueous dispersion in which the pigment is dispersed, the pigment dispersion state can be stably obtained even in the state where it coexists with the water-soluble organic solvent, other additives and the like.

<Α-Olefin Copolymer Having Acidic Group>
The α-olefin copolymer having an acidic group is a copolymer of an α-olefin and an acidic group-containing monomer.

(Α-olefin)
An α-olefin is a compound having 5 to 50 carbon atoms. As for carbon number of alpha olefin, 10-30 are preferred. When the number of carbon atoms is 5 to 50, it becomes easier to coat the pigment surface, and the dispersibility of the coated pigment is further improved.

 The α-olefin is, for example, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 1-docosene. 1-tetracocene, 1-octacocene, 1-triacontene, 1-dotriacontene, 1-tetratriacontene, 1-hexatriatainene, 1-octatriacontene and the like.

 The α-olefin can be used alone or in combination of two or more.

(Acid group-containing monomer)
The acidic group-containing monomer is a compound having a functional group (ethylenically unsaturated double bond) capable of radical polymerization with an α-olefin and an acidic group. Examples of the ethylenically unsaturated double bond include a vinyl group, an allyl group, and a (meth) acryl group. Examples of the acidic group include a carboxyl group, an acid anhydride group, a sulfo group, and a phosphoric acid group. Among these, a carboxyl group and an acid anhydride group are preferable in consideration of formation of a graft chain.

 Examples of the acidic group-containing monomer include (meth) acrylic acid, (meth) acrylic acid dimer, itaconic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, 2- (meth) acryloyloxyethyl phthalate, 2- (Meth) acryloyloxypropyl phthalate, 2- (meth) acryloyloxyethyl hexahydrophthalate, 2- (meth) acryloyloxypropyl hexahydrophthalate, ethylene oxide-modified succinic acid (meth) acrylate, β-carboxyethyl ( And (meth) acrylate and ω-carboxypolycaprolactone (meth) acrylate. Among these, (meth) acrylic acid, maleic acid, and maleic anhydride are preferable.

 An acidic group containing monomer can be used individually or in combination of 2 or more types.

(Other monomers)
For the synthesis of the α-olefin copolymer having an acidic group, other monomers can be used as necessary.
Other monomers are monomers other than α-olefins and acidic group-containing monomers.
Other monomers include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth), tertiary butyl (meth) acrylate, isoamyl (Meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cetyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, tridecyl Linear or branched alkyl (meth) acrylates such as (meth) acrylate, isomyristyl (meth) acrylate, stearyl (meth) acrylate, and isostearyl (meth) acrylate Cyclohexyl (meth) acrylate, tertiary butyl cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentanyloxyethyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxy Cyclic alkyl (meth) acrylates such as ethyl (meth) acrylate and isobornyl (meth) acrylate; tetrahydrofurfuryl (meth) acrylate, and heterocyclic rings such as 3-methyl-3-oxetanyl (meth) acrylate (meth) Acrylate: benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, paracumylphenoxyethyl (meth) acrylate, Cumylphenoxypolyethylene glycol (meth) acrylate and (meth) acrylate having an aromatic ring such as nonylphenoxypolyethylene glycol (meth) acrylate; trifluoroethyl (meth) acrylate, octafluoropentyl (meth) acrylate, perfluorooctyl Fluoroalkyl (meth) acrylates such as ethyl (meth) acrylate and tetrafluoropropyl (meth) acrylate; (meth) acryloxy-modified polydimethylsiloxane (silicone macromer); 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl ( (Meth) acrylate, 3-methoxybutyl (meth) acrylate, 2-methoxypropyl (meth) acrylate, diethylene glycol monomethyl ether (meth) ) Acrylate, diethylene glycol monoethyl ether (meth) acrylate, triethylene glycol monomethyl ether (meth) acrylate, triethylene glycol monoethyl ether (meth) acrylate, diethylene glycol mono-2-ethylhexyl ether (meth) acrylate, dipropylene glycol monomethyl ether (Poly) alkylene glycol monoalkyl ether (meth) acrylates such as (meth) acrylate, tripropylene glycol mono (meth) acrylate, polyethylene glycol monolauryl ether (meth) acrylate, and polyethylene glycol monostearyl ether (meth) acrylate; (Meth) acrylamide, dimethyl (meth) acrylamide, N, N-diethyl N-substituted (meth) acrylamides such as (meth) acrylamide, N-isopropyl (meth) acrylamide, diacetone (meth) acrylamide, and acryloylmorpholine; nitriles such as (meth) acrylonitrile; styrene, and α-methylstyrene Styrene; vinyl ethers such as ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, and isobutyl vinyl ether; fatty acid vinyls such as vinyl acetate and vinyl propionate; (meth) acrylate monomers having a hydroxyl group, such as 2 -Hydroxyethyl (meth) acrylate, 2 (or 3) -hydroxypropyl (meth) acrylate, 2 (or 3 or 4) -hydroxybutyl (meth) acrylate And hydroxyalkyl (meth) acrylates such as cyclohexanedimethanol mono (meth) acrylate, or (meth) acrylamide monomers having a hydroxyl group, such as N- (2-hydroxyethyl) (meth) acrylamide, N- (2- N- (hydroxyalkyl) (meth) acrylamide such as hydroxypropyl) (meth) acrylamide, N- (2-hydroxybutyl) (meth) acrylamide, or vinyl ether monomers having a hydroxyl group, such as 2-hydroxyethyl vinyl ether, 2- (or 3-) hydroxypropyl vinyl ether, hydroxyalkyl vinyl ethers such as 2- (or 3- or 4-) hydroxybutyl vinyl ether, or allyl ether monos having a hydroxyl group Mer, for example, hydroxyalkyl allyl ethers such as 2-hydroxyethyl allyl ether, 2- (or 3-) hydroxypropyl allyl ether, 2- (or 3- or 4-) hydroxybutyl allyl ether, Hydroxyl group-containing compounds such as ethylenically unsaturated monomers obtained by adding alkylene oxide and / or lactone to (meth) acrylate, N- (hydroxyalkyl) (meth) acrylamide, hydroxyalkyl vinyl ether or hydroxyalkyl allyl ether; vinyl Sulfonic acid-containing compounds such as sulfonic acid, acrylonitrile t-butylsulfonic acid, ethylenically unsaturated double bond-containing compounds having a betaine structure; N, N-dimethylaminoethyl (meth) acrylate (Meth) acrylates having a tertiary amino group such as N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-diethylaminopropyl (meth) acrylate; N, N -Tertiary amino groups such as dimethylaminoethyl (meth) acrylamide, N, N-diethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, and N, N-diethylaminopropyl (meth) acrylamide (Meth) acrylamide;

 Other monomers can be used alone or in combination of two or more.

(Synthesis of α-olefin copolymer having acidic group)
The α-olefin copolymer having an acidic group is synthesized by radical polymerization of an α-olefin and an acidic group-containing monomer. The radical polymerization can be arbitrarily selected from solution polymerization, emulsion polymerization, suspension polymerization, bulk polymerization and the like, and solution polymerization and bulk polymerization are preferable.
The synthesis method in the solution polymerization is, for example, polymerization using an α-olefin and an acidic group-containing monomer, a polymerization initiator, an organic solvent, and, if necessary, a chain transfer agent. If no organic solvent is used in the reaction, bulk polymerization occurs.
In this specification, when maleic anhydride is used as the acidic group-containing monomer, an alternating polymer of α-olefin units and maleic anhydride units is easily formed. When (meth) acrylic acid is used as the product of the reaction, an α-olefin unit, (meth) acrylic acid, and a random copolymer are easily formed.

  The molar ratio of the α-olefin (O) and the acidic group-containing monomer (M) is preferably O / M = 30/70 to 99/1, more preferably 40/60 to 95/5, and 45/55 to 80. / 20 is more preferable. When an appropriate amount of the α-olefin (O) and the acidic group-containing monomer (M) are used, the dispersion stability of the coated pigment is further improved.

 The polymerization initiator is preferably an azo compound or a peroxide. Examples of the azo compound include azobisisobutyronitrile, azobis 2,4-dimethylvaleronitrile, and the like. Examples of the peroxide include cumene hydroperoxide, t-butyl hydroperoxide, benzoyl peroxide, diisopropyl peroxycarbonate, di-t-butyl peroxide, lauroyl peroxide, t-butyl peroxybenzoate, t- And butyl peroxy-2-ethylhexanoate.

 The acid value of the α-olefin copolymer having an acidic group is preferably 5 to 300 mgKOH / g, more preferably 20 to 200 mgKOH / g, and still more preferably 30 to 160 mgKOH / g. Most preferably, it is 50-160 mgKOH / g. When the acid value is adjusted to an appropriate range, the dispersibility of the coated pigment is further improved.

 The weight average molecular weight of the α-olefin copolymer having an acidic group is preferably 1,000 to 50,000, and more preferably 1,000 to 35,000. When the weight average molecular weight is adjusted to an appropriate range, the dispersibility is further improved. Moreover, it is easy to adjust the viscosity of the pigment aqueous dispersion to an appropriate range.

(Α-olefin copolymer having graft chain and acidic group)
The α-olefin copolymer having an acidic group preferably has a graft chain.
The graft chain can be formed by, for example, 1) reacting a compound having a graft chain and having a reactive functional group (hereinafter referred to as a reactive functional group) with the acidic group. In such a case, the acid group is preferably an acid anhydride group or a carboxyl group, and more preferably an acid anhydride group. When an acid anhydride group is used, an unreacted carboxyl group that does not contribute to graft chain formation contributes to an improvement in hydrophilicity of the coated pigment. Examples of the reactive functional group include a hydroxyl group and an amino group.
2) Another method for forming a graft chain can be formed, for example, by copolymerizing a monomer having a graft chain when synthesizing an α-olefin copolymer having an acidic group. Needless to say, the formation of graft chains is not limited to these methods.

  The acid value and weight average molecular weight of the α-olefin copolymer having a graft chain and an acidic group are the same as those already described.

  Examples of the partial structure of the graft chain of the α-olefin copolymer having a graft chain and an acidic group include structures represented by the general formulas (1) to (3). In addition, the monovalent bond in the following structure is bonded to —C (O) — of the acidic group in the α-olefin copolymer in the above method 1). If it is the method of said 2), it is (meth) acrylic acid ester and couple | bonds with -C (O)-of meth) acrylic acid, for example. Formation of the graft chain is carried out by a known reaction method.

[一般式（１）中、Ｒ₁は置換されているＣ₆〜Ｃ₃₀のアルキル基、置換されていてもよい脂環式構造、置換されていてもよいフェニル基を表す] Structure represented by general formula (1)

[In General Formula (1), R ₁ represents a substituted C _{6 to} C ₃₀ alkyl group, an optionally substituted alicyclic structure, or an optionally substituted phenyl group]

 The structure represented by the general formula (1) can be formed, for example, by a reaction between an acidic group or (meth) acrylic acid in the α-olefin copolymer and a hydroxyl group-containing compound. Examples of the hydroxyl group-containing compound include isopropanol, α-oxybutyric acid, 12-hydroxystearic acid, lactic acid, glycolic acid, cyclohexyl alcohol, and benzyl alcohol.

Structure represented by general formula (2)

[In General Formula (2), R ₁ and R ₂ are each a hydrogen atom, an optionally substituted C _{1 to} C ₃₀ alkyl group, an optionally substituted alicyclic structure, and optionally substituted. Represents a phenyl group. However, when _one of R ₁ and R ₂ is a hydrogen atom, the other is not a hydrogen atom. ]

 The structure represented by the general formula (2) can be formed, for example, by a reaction between an acidic group or (meth) acrylic acid in an α-olefin copolymer and an amino group-containing compound. An amino group-containing compound is a compound having one amino group, for example, methylamine, ethylamine, propylamine, isopropylamine, butylamine, amylamine, hexylamine, cyclohexylamine, heptylamine, octylamine, nonylamine, decylamine, lauryl. Amine, myristylamine, cetylamine, stearylamine, oleylamine, aniline, o-toluidine, 2-ethylaniline, 2-fluoroaniline, o-anisidine, m-toluidine, m-anisidine, m-phenetidine, p-toluidine, 2, Examples include 3-dimethylaniline, 5-aminoindane, aspartic acid, glutamic acid, and γ-aminobutyric acid.

Structure represented by general formula (3)

[In General Formula (3), R ₁ represents a hydrogen atom, an alkyl group having 6 to 20 carbon atoms, or a phenyl group optionally substituted with an alkyl group having 1 to 9 carbon atoms, and A ¹ O and A ² O independently represents an alkyleneoxy group having 1 to 6 carbon atoms, m and n represent an average number of added moles of the alkyleneoxy group, an integer of 0 to 100, and m + n is 1 or more. is there. ]

 The structure represented by the general formula (3) can be formed, for example, by a reaction between an acidic group or (meth) acrylic acid in an α-olefin copolymer and an alkyleneoxy group-containing compound.

  Examples of the alkyleneoxy group-containing compound include polyalkylene glycols such as polyethylene glycol and polypropylene glycol; polyoxyethylene monomethyl ether, polyoxypropylene monomethyl ether, polyoxyethylene-2-ethylhexyl ether, and polyoxyethylene isodecyl ether. Oxyalkylene alkyl ethers. Of these, polyoxyethylene monomethyl ether is preferred. Commercial products of the alkyleneoxy group-containing compound include, for example, UNIOX M-400, M-550, and M-1000 (manufactured by NOF Corporation).

  The graft chains can be used alone or in combination of two or more.

The coated pigment of the present specification is selected from the group consisting of a styrene- (meth) acrylic resin, a styrene- (anhydrous) maleic acid resin, and a (meth) acrylic resin in addition to the α-olefin copolymer having an acidic group. 1 or more types can be included.
These resins are publicly known resins. For example, in the case of a styrene (meth) acrylic resin, Joncyrl series (manufactured by BASF) represented by Joncryl 690, 67, X-1 (Starlight PMC) SMA resin series (manufactured by Cray Valley) represented by SMA 1440, SMA 2625, SMA 3840, etc. for styrene (anhydrous) maleic resin, and VS-1057, X-310, TS- for (meth) acrylic resin. 1316 (manufactured by Seiko PMC) or the like.

<Uncoated pigment (B)>
The pigment (B) coated on the copolymer used in the present invention is not particularly limited as long as it does not depart from the spirit of the present invention, and various conventionally known inorganic pigments or organic pigments are appropriately selected and used. be able to.

  Examples of the inorganic pigment include metal compounds represented by metal oxides, metal complex salts, and the like. Specifically, iron, cobalt, aluminum, cadmium, lead, copper, titanium, magnesium, chromium, zinc, antimony And metal oxides such as the above, and complex oxides of the above metals.

  As the pigment (B), an untreated pigment is usually used, but a pigment that has undergone some treatment process may be used. In particular, if untreated, the coating of the resin proceeds easily and the target pigment (A) is easily obtained. The pigment (B) can be used alone or in combination.

Examples of the organic pigment include:
C. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 9, 10, 14, 17, 22, 23, 31, 32, 38, 41, 48: 1, 48: 2, 48: 3, 48: 4, 49, 49: 1, 49: 2, 52: 1, 52: 2, 53: 1, 57: 1, 60: 1, 63: 1, 66, 67, 81: 1, 81: 2, 81: 3, 83, 88, 90, 105, 112, 119, 122, 123, 144, 146, 147, 148, 149, 150, 155, 166, 168, 169, 170, 171, 172, 175, 176, 177, 178, 179, 184, 185, 187, 188, 190, 200, 202, 206, 207, 208, 209, 210, 216, 220, 224, 226, 242, 246, 254, 255, 264, 266, 269, 270 272,279,
C. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 10, 11, 12, 13, 14, 15, 16, 17, 18, 20, 24, 31, 32, 34, 35, 35: 1, 36, 36: 1, 37, 37: 1, 40, 42, 43, 53, 55, 60, 61, 62, 63, 65, 73, 74, 77, 81, 83, 86, 93, 94, 95, 97, 98, 100, 101, 104, 106, 108, 109, 110, 113, 114, 115, 116, 117, 118, 119, 120, 123, 125, 126, 127, 128, 129, 137, 138, 139, 147, 148, 150, 151, 152, 153, 154, 155, 156, 161, 162, 164, 166, 167, 168, 169, 170, 171, 172, 173, 17 , 175,176,177,179,180,181,182,185,187,188,193,194,199,213,214, C. I. Pigment Orange 2, 5, 13, 16, 17: 1, 31, 34, 36, 38, 43, 46, 48, 49, 51, 52, 55, 59, 60, 61, 62, 64, 71, 73,
C. I. Pigment Green 7, 10, 36, 37, 58, 62, 63,
C. I. Pigment Blue 1, 2, 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, 22, 60, 64, 66, 79, 79, 80
C. I. Pigment Violet 1, 19, 23, 27, 32, 37, 42
C. I. Pigment Brown 25, 28
C. I. Pigment Black 1, 7 and the like.

Among these, the pigments that can be preferably used include the following. These pigments maintain sufficient color reproducibility and / or lightfastness as inks for inkjet printing, ink for flexographic printing, toner, ink for silk screen printing, paint, gravure printing ink, and ink for offset printing. can do. However, the present invention is not limited to these.
C. I. Pigment Red 48: 1, 48: 2, 48: 3, 48: 4, 57: 1, 122,146, 147, 148, 150, 170, 176, 177, 184, 185, 242, 254, 255, 264, 266, 269,
C. I. Pigment Yellow 12, 13, 14, 17, 74, 83, 93, 108, 109, 120, 150, 151, 154, 155, 180, 185, 213
C. I. Pigment Orange 36, 38, 43, 64
C. I. Pigment Green 7, 36, 37, 58, 62, 63
C. I. Pigment Blue 15: 1, 15: 3, 15: 6, 16, 22, 60, 66,
C. I. Pigment Violet 19, 23, 32,
C. I. Pigment Brown 25,
C. I. Pigment Black 1, 7

<Resin coating amount = resin adsorption amount>
To 100 g of ion-exchanged water, an equivalent amount of potassium hydroxide is added and dissolved with respect to the acid value of the resin treated with the pigment (A), and the concentration of the pigment (A) is 15% by mass. After adding the pigment (A), the liquid temperature is set to 70 ° C. and the mixture is stirred for 2 hours to obtain a pigment dispersion. This dispersion is then precipitated with a centrifuge at 70,000 rpm for 20 hours, and the supernatant is collected all over and further centrifuged with a centrifuge at 70,000 rpm for 20 hours. The entire supernatant is collected and the solid content is determined from the drying method, the mass of the resin released from the pigment (A) is determined, and the mass of the resin added when the pigment (A) is produced is adsorbed to the pigment. The amount of resin adsorbed to the entire pigment (A) is calculated. This was evaluated as the coating state of the pigment. When one or more resins selected from a styrene (meth) acrylic resin, a styrene (anhydrous) maleic acid resin, and a (meth) acrylic resin were used alone or in combination with a copolymer, they were evaluated by the same method as described above. The adsorption amount of the resin in the present invention is 10% by mass or more and 50% by mass or less with respect to the pigment (B). If the amount is less than 10% by mass, the pigment is not sufficiently covered with the resin, so that aggregation occurs and it is difficult to disperse the coarse particles. On the other hand, when the amount exceeds 50% by mass, the pigment is excessively hydrophilized, and the water resistance of the printed matter after inkjet printing cannot be ensured.

<Method for producing pigment (A)>
The method for producing the pigment (A) of the present invention is preferably a method in which at least a water-soluble inorganic salt, a water-soluble organic solvent for kneading and a resin are added to the pigment (B), and the resin is coated on the pigment by grinding and kneading. The method of coating the pigment by milling and kneading is not particularly limited, and any method can be applied, but a kneading step by so-called salt milling is suitable. In particular,
Step (1) A water-soluble organic solvent for kneading, an inorganic salt, a pigment (B) not coated with an α-olefin copolymer having an acidic group, and a copolymer containing α-olefin units in a straight chain are mixed in a kneader. The process of
Step (2) After the mixing step, removing the inorganic salt and the water-soluble organic solvent for kneading,
It is preferable to manufacture via.

<Step (1)>
The kneading method is a mixture comprising at least a pigment (B), a water-soluble inorganic salt, a water-soluble organic solvent for kneading, and a resin, kneader, trimix, two roll mill, three roll mill, ball mill, attritor, horizontal sand mill, vertical type. It can be carried out using a kneader such as a sand mill or / and an annular bead mill. Among these, a kneader or a trimix is preferable. If it is these, it is possible to knead the pigment (B), the water-soluble inorganic salt, the mixture of the water-soluble organic solvent for kneading and the resin with high viscosity, and the coating of the pigment and the dispersion of the coarse particles proceed effectively. The treatment conditions may be appropriately adjusted according to the type of pigment, the required degree of coating, and the like. Heating is preferably performed when mechanically kneading. The upper limit temperature of heating can be arbitrarily set as long as the resin does not cause thermal decomposition. Furthermore, if it is higher than the melting point of the resin used, the resin processing efficiency can be obtained effectively. The water-soluble inorganic salt has an effect of acting as a function of grinding in addition to dispersing the aggregated pigment. The pigment is crushed using the high hardness of the water-soluble inorganic salt during salt milling. By optimizing the conditions for the salt milling treatment, a pigment having a very fine primary particle diameter, a narrow distribution width, and a sharp particle size distribution can be obtained.

<Step (2)>
After performing the step (1), for example, the pigment (A) can be obtained by the following treatment. The mixture containing the pigment (A) is taken out from the grinding kneader, charged with ion-exchanged water and stirred to obtain a suspension. The amount of water to be added is not particularly limited as long as it is sufficient to obtain a suspension. You may heat as needed. For example, water having a mass of 10 to 10,000 times the mass of the step (1) is added and mixed and stirred. Although the mixing stirring conditions at this time are not specifically limited, It is preferable to carry out at the temperature of 25-90 degreeC. Next, by removing the filtrate by an operation such as filtration, the water-soluble organic solvent and water-soluble inorganic salt used in the milling kneader can be removed, and the pigment (B) has an unneutralized acidic group. The α-olefin copolymer (A) can be obtained. Further, by neutralizing the resin, a pigment dispersion in which the pigment (A) is uniformly dispersed in water can be obtained.

 Since the pigment (A) contains ion-exchanged water, a step of further removing water may be performed. Although it will not be limited if it is the method of removing water, The method of performing a drying process can be mentioned as a suitable method. Examples of drying conditions include a method of drying for 12 to 48 hours at 80 to 120 ° C. under normal pressure, and a method of drying for 12 to 60 hours at 25 to 80 ° C. under reduced pressure. It can be illustrated. Although a drying process is not specifically limited, The method using a spray drying apparatus can also be illustrated. A pulverization process may be performed simultaneously with the drying process or after the drying process. Thereby, the pigment (A) can be obtained depending on the purpose, including those containing ion-exchanged water and those in a dry state from which the ion-exchanged water has been extremely removed. The amount of ion-exchanged water contained in the pigment (A) can be arbitrarily set.

(Water-soluble organic solvent for kneading)
As the water-soluble organic solvent, any solvent can be used as long as it is dissolved and mixed in water. Specifically, glycerin, ethylene glycol, propanediol, butanediol, pentanediol, hexanediol, diethylene glycol, dipropylene glycol, perethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol Propylene glycol monomethyl ether, 2-ethyl-1,3-hexanediol, 2,4-diethyl-1,5-pentanediol, monoacetin), diacetin, triacetin, tripropionine, tributyrin and 2-butyl-2-ethyl-1, Although 3-propanediol is mentioned, it is not restricted to this. These solvents can be used alone or in combination. The amount of the water-soluble organic solvent to be added is not particularly limited, but it is preferably 5 to 1,000 parts by mass, more preferably 50 to 500 parts by mass with respect to 100 parts by mass of the pigment.

(Water-soluble inorganic salt)
The water-soluble inorganic salt is not limited as long as it is an inorganic salt that exhibits water-solubility as its name does not depart from the spirit of the present invention. Preferred examples include sodium chloride, barium chloride, potassium chloride, sodium sulfate and the like. It is preferable to use sodium chloride (salt) from the viewpoint of price. The water-soluble inorganic salt is preferably used in an amount of 50 to 2,000 parts by mass, more preferably 300 to 1,000 parts by mass with respect to 100 parts by mass of the pigment, from both the treatment efficiency and the production efficiency.

(Pigment aqueous dispersion)
The aqueous pigment dispersion of the present invention can be obtained from the pigment (A), water and a basic substance.

(Water, basic substance)
As water, general water such as tap water can be used, but it is preferable to use ion-exchanged water or distilled water. As the basic substance, either an inorganic base or an organic base can be used. Specifically, any inorganic base can be used as long as it is soluble in water. For example, potassium hydroxide, sodium hydroxide, sodium hydrogen carbonate, sodium carbonate and the like can be mentioned, but not limited thereto. Any organic base can be used as long as it is soluble in water. For example, primary to tertiary amines can be used. For example, alkylamines such as ammonia, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, and triethylamine. Alkanolamines such as aminoethanol, methylaminoethanol, dimethylaminoethanol, ethylaminoethanol, diethylaminoethanol, diethanolamine and triethanolamine. Examples include, but are not limited to, amines having a nonionic group such as methoxypoly (oxyethylene / oxypropylene) -2-propylamine.

 Furthermore, if necessary, interfaces such as cross-linking agents, preservatives, leveling agents, surface tension modifiers, antifoaming agents, anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, etc. An activator, a water-soluble resin, an emulsion and the like can be optionally added.

(Crosslinking agent)
In particular, the crosslinking agent is very important for improving the storage stability of inkjet ink, pigment dispersion state in the production process of polymerized toner, flexographic ink, paint, gravure ink, offset ink, stationery and the like. However, in order to obtain a sufficient crosslinking agent effect, the pigment (B) needs to be sufficiently adsorbed with a compound having a reactive functional group capable of reacting with the crosslinking agent. The amount of resin adsorption suitable for crosslinking can be measured by the above method and is 10% by mass or more based on the pigment (B). When the content is 10% by mass or more, the pigment is sufficiently covered with the resin, so that a sufficient crosslinking effect can be obtained.

 As the crosslinking agent in the present invention, a compound having a reactive functional group capable of reacting with two or more carboxyl groups in the molecule is preferably used in order to appropriately crosslink a copolymer containing α-olefin units in a straight chain. It is done. Specific examples of the reactive functional group preferably include one or more selected from the group consisting of isocyanate, aziridine, carbodiimide, oxetane, oxazoline, and epoxy group. The molecular weight of the cross-linking agent is preferably 100 to 2000, more preferably 120 to 1500, and particularly preferably 150 to 1000 from the viewpoint of easy reaction and storage stability of the resulting cross-linked colorant particles. The number of reactive functional groups contained in the crosslinking agent is preferably 2 to 6 from the viewpoint of controlling the molecular weight and improving storage stability.

Specific examples of the crosslinking agent used in the present invention include the following.
Compound having two or more isocyanate groups in the molecule: for example, organic polyisocyanate or isocyanate group-terminated prepolymer,
Examples of organic polyisocyanates include aliphatic diisocyanates such as hexamethylene diisocyanate and 2,2,4-trimethylhexamethylene diisocyanate; aromatic diisocyanates such as tolylene-2,4-diisocyanate and phenylene diisocyanate; alicyclic diisocyanates; aromatic Triisocyanate; and modified products such as urethane modified products thereof. The isocyanate group-terminated prepolymer can be obtained by reacting an organic polyisocyanate or a modified product thereof with a low molecular weight polyol or the like.

  Compounds having two or more aziridine groups in the molecule: for example, N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxite), N, N′-toluene-2,4-bis (1 -Aziridinecarboxite), bisisophthaloyl-1- (2-methylaziridine), tri-1-aziridinylphosphine oxide, N, N'-hexamethylene-1,6-bis (1-aziridinecarboxite) 2,2′-bishydroxymethylbutanol-tris [3- (1-aziridinyl) propionate], trimethylolpropane tri-β-aziridinylpropionate, tetramethylolmethane tri-β-aziridinylpropionate , Tris-2,4,6- (1-aziridinyl) -1,3,5-triazine, 4,4′-bis (ethyleneiminocarbo Nylamino) diphenylmethane and the like.

  Compound having two or more carbodiimide groups in the molecule: for example, high molecular weight polycarbodiimide produced by decarboxylation condensation reaction of a diisocyanate compound in the presence of a carbodiimidization catalyst. Examples of such high molecular weight polycarbodiimides include Nisshinbo's Carbodilite series.

  Compounds having two or more oxetane groups in the molecule: for example, 4,4 ′-(3-ethyloxetane-3-ylmethyloxymethyl) biphenyl (OXBP), 3-ethyl-3-hydroxymethyloxetane (EHO) 1,4-bis [{(3-ethyl-3-oxetanyl) methoxy} methyl] benzene (XDO), di [1-ethyl (3-oxetanyl)] methyl ether (DOX), di [1-ethyl (3 -Oxetanyl)] methyl ether (DOE), 1,6-bis [(3-ethyl-3-oxetanyl) methoxy] hexane (HDB), 9,9-bis [2-methyl-4- {2- (3- Oxetanyl)} butoxyphenyl] fluorene, 9,9-bis [4- [2- {2- (3-oxetanyl)} butoxy] ethoxyphenyl] fluorene, and the like.

 Compound having two or more oxazoline groups in the molecule: For example, a compound in which two or more, preferably 2-3 oxazoline groups are bonded to an aliphatic group or an aromatic group, more specifically 2, 2′- Bisoxazoline compounds such as bis (2-oxazoline), 1,3-phenylenebisoxazoline, 1,3-benzobisoxazoline, and compounds having a terminal oxazoline group obtained by reacting the compound with a polybasic carboxylic acid.

 Compounds having two or more epoxy groups in the molecule: for example, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerin triglycidyl ether, glycerol polyglycidyl ether, polyglycerol polyglycidyl ether, tri Polyglycidyl ethers such as methylolpropane polyglycidyl ether, sorbitol polyglycidyl ether, pentaerythritol polyglycidyl ether, resorcinol diglycidyl ether, neopentyl glycol diglycidyl ether, hydrogenated bisphenol A type diglycidyl ether.

 Among these, compounds having two or more epoxy groups in the molecule are preferable, and ethylene glycol diglycidyl ether and trimethylolpropane polyglycidyl ether are particularly preferable. The crosslinking agent is preferably moderately water-soluble from the viewpoint of efficiently surface-crosslinking the polymer. For example, when the crosslinking agent is dissolved in 100 g of water at 25 ° C., the dissolution amount is 0.1 to 50 g. Preferably, 0.2-40g is more preferable, More preferably, 0.5-30g is the most preferable.

<Manufacture of pigment dispersion>
As a method for preparing the pigment dispersion, an appropriate amount of a basic substance such as potassium hydroxide is added to ion-exchanged water with respect to the acid value of the resin treated when preparing the pigment (A) and dissolved therein. (A) can be added and stirred while heating. The basic substance such as potassium hydroxide is preferably added in an amount of 120% or less with respect to the acid value of the resin treated when the pigment (A) is produced. More preferably, it is 100% or less. If it is this range, the pH of a pigment dispersion is not too high, and it is easy to design the ink which does not destroy the material of an inkjet head after ink-izing. Any method and apparatus may be used for stirring as long as uniform mixing is possible. For example, specific examples of the apparatus include the following. High speed mixer, homogenizer, planetary mixer, trimix, kneader, extruder, horizontal sand mill, vertical sand mill or / and annular bead mill, paint shaker, ball mill, disperser equipped with ultrasonic oscillator, two roll mill 3 roll mills are listed but not limited to this.

 Furthermore, a crosslinked pigment dispersion can be prepared by crosslinking a resin coated with the pigment (A) using a crosslinking agent in the pigment dispersion. The crosslinking reaction proceeds by the reaction between the carboxyl group of the resin and the crosslinking agent. Therefore, when making a crosslinked pigment dispersion, it is necessary that the resin has a carboxyl group. Preferred examples of such a resin include a maleic anhydride and α-olefin copolymer, or a maleic acid graft polymer of a maleic anhydride and α-olefin copolymer. In the case of an acid anhydride such as maleic anhydride, it is desirable that the acid anhydride is hydrolyzed. If a crosslinked pigment dispersion is prepared after hydrolysis, the reaction rate and reaction rate can be sufficiently obtained, the production time can be shortened, and sufficient performance can be obtained.

 As for the pigment dispersion used when preparing the crosslinked pigment dispersion, it is desirable that the basic substance used when preparing the pigment dispersion is an inorganic base or a combination of an inorganic base and the above-mentioned organic base. As the inorganic base, specifically, those described above can be used. The reaction of the crosslinking agent is more likely to proceed when an inorganic base is used.

 As a method for producing a crosslinked pigment dispersion, it can be produced by adding a crosslinking agent to the pigment dispersion and stirring it. Any apparatus can be used as long as the apparatus can perform the stirring which can be used when the pigment dispersion is prepared. Furthermore, you may heat as needed for the purpose of promoting reaction. If the pH needs to be adjusted after completion of the reaction, it can be adjusted to the target pH with any acid. Specific examples include inorganic acids such as phosphoric acid, hydrochloric acid, sulfuric acid and nitric acid, and organic acids such as citric acid. Moreover, it is also possible to add a centrifugation process and a filtration process. The addition amount of the crosslinking agent is preferably an amount for reacting 1 to 100 mol% of the carboxyl group of the copolymer containing the α-olefin unit in a straight chain. Among them, it is more preferable to add an amount for reacting 1 to 50 mol%.

 By adding a cross-linking agent to the pigment dispersion and cross-linking the resin coated with the pigment, the water-soluble ink such as inkjet ink is formed with a dispersion medium (water, other additives, etc.) in which the pigment is dispersed. Stability against pigment aggregation due to changes in the component (the viscosity and particle size distribution do not change immediately after the change of the dispersion medium and after long-term storage) is extremely high. There are several hypotheses, but it is speculated that the resin coated with pigments is cross-linked to form a network with a large molecular weight on the pigment surface. Thereby, even if the adsorption equilibrium of the resin adsorbed to the pigment is changed due to the change of the dispersion medium in which the pigment is dispersed, it is considered that the resin is difficult to desorb from the pigment and the stability can be maintained. Another reason is that the cross-linking base has an effect of introducing a steric hindrance site into the resin adsorbed on the pigment. It is inferred that stability is imparted by this steric hindrance site.

 Examples of the method for producing the crosslinked pigment dispersion of the present invention include the following. A step of kneading a mixture containing an uncoated pigment (B), a maleic acid graft polymer of a copolymer of maleic anhydride and α-olefin, a water-soluble inorganic salt and a water-soluble organic solvent; The step of removing water-soluble inorganic salt and water-soluble organic solvent, the step of adding a basic compound to neutralize the maleic acid graft polymer of maleic anhydride and α-olefin copolymer, and the addition of a crosslinking agent Then, the step of reacting the maleic acid graft polymer of maleic anhydride and α-olefin copolymer with the crosslinking agent is a sequential production method.

  The volume average particle diameter (D50) of the pigment dispersion and the crosslinked pigment dispersion of the present invention is preferably 200 nm or less from the viewpoint of the sharpness, coloring power and color reproducibility of the printed matter. Preferably it is 150 nm or less, More preferably, it is 100 nm or less, More preferably, 90 nm or less is good. The smaller the volume average particle diameter is, the better the sharpness, coloring power and color reproducibility of the printed matter. Further, in order to obtain good print clarity, coloring power, and color reproducibility, the volume average particle diameter (D99) is preferably suppressed to 500 nm or less at the upper limit of the pigment dispersion particles.

<Water-soluble ink>
The water-soluble ink of the present invention is suitably used for various applications as a colorant and the like, and is particularly suitably used as an inkjet ink described below.

(Inkjet ink)
The inkjet ink using the pigment (A) of the present invention contains a basic substance, water, and a water-soluble solvent with respect to the pigment (A). Furthermore, surfactants such as anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, water-soluble resins, emulsions, pH adjusters, and other components are added as necessary. May be.

  The volume average particle diameter (D50) of the inkjet ink using the pigment (A) of the present invention is preferably 150 nm or less, more preferably 100 nm or less. More preferably, it is 50 nm or less. When the volume average particle diameter (D50) is 100 nm or less, ejection stability is improved, and image saturation and image density (OD value) are also improved. The content of the pigment (A) in the inkjet ink is preferably 1 to 15% by mass, more preferably 2 to 10% by mass, based on the solid content of the pigment (B). When the content is less than 1% by mass, the color developability and the image density of the ink may be extremely low. When the content exceeds 15% by mass, the ink is thickened and the dischargeability is deteriorated. In some cases, it is also not economical.

(Basic substance)
As the basic substance, either an inorganic base or an organic base can be used. Specifically, any inorganic base can be used as long as it is soluble in water. For example, potassium hydroxide, sodium hydroxide, sodium hydrogen carbonate, sodium carbonate and the like can be mentioned, but not limited thereto. Any organic base can be used as long as it is soluble in water. For example, primary to tertiary amines can be used. For example, alkylamines such as ammonia, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, and triethylamine. Alkanolamines such as aminoethanol, methylaminoethanol, dimethylaminoethanol, ethylaminoethanol, diethylaminoethanol, diethanolamine and triethanolamine. Examples include, but are not limited to, amines having a nonionic group such as methoxypoly (oxyethylene / oxypropylene) -2-propylamine.

(water)
As the water, any water such as tap water can be used, but it is desirable to use ion-exchanged water, distilled water, or purified water.

<Water-soluble organic solvent>
The ink-jet ink of the present invention uses water as a liquid medium. In order to prevent the ink from drying and to improve the dispersion stability, the permeability to the substrate after printing, the wet spreading property, etc. For this purpose, the following water-soluble organic solvents are used. The water-soluble solvent intended to prevent drying and improve dispersion stability is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include polyhydric alcohols and polyhydric alcohol alkyl ethers. And polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, sulfur-containing compounds, propylene carbonate, ethylene carbonate, and other water-soluble solvents. These may be used individually by 1 type and may use 2 or more types together. In addition, as a water-soluble organic solvent, ether is preferable, alcohol alkyl ether is preferable, and polyhydric alcohol alkyl ether is more preferable.

 Examples of the polyhydric alcohol alkyl ethers include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol. Examples thereof include monoethyl ether and propylene glycol monobutyl ether.

  Examples of the polyhydric alcohol aryl ethers include ethylene glycol monophenyl ether, diethylene glycol monophenyl ether, tetraethylene glycol chlorophenyl ether, ethylene glycol monobenzyl ether, and ethylene glycol monoallyl ether.

As the water-soluble organic solvent, the following solvents can be used in combination with ether.
Examples of the polyhydric alcohols include glycerin, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, Polypropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5-pentane Diol, 1,2-hexanediol, 1,3-hexanediol, 1,4-hexanediol, 1,5-hexanediol, 1,6-hexanediol, 3-methyl-1,3-butanediol, trimethylol Ethane, Trimethi Propane, 1,2,6-hexanetriol, 1,2,4-butanetriol, 1,2,3-butanetriol, petriol, 2-ethyl-2-methyl-1,3-propanediol, 3,3 -Dimethyl-1,2-butanediol, 2,2-diethyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2,4-dimethyl-2,4-pentanediol 2,5-dimethyl-2,5-hexanediol, 5-hexene-1,2-diol, 2-ethyl-1,3-hexanediol and the like.

Examples of the nitrogen-containing heterocyclic compound include 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, ε-caprolactam, γ-butyrolactone, Etc.
Examples of the amides include formamide, N-methylformamide, N, N-dimethylformamide, and the like.
Examples of the amines include monoethanolamine, diethanolamine, triethanolamine, monoethylamine, diethylamine, triethylamine, and the like.
Examples of the sulfur-containing compounds include dimethyl sulfoxide, sulfolane, thiodiethanol, and the like.

The other water-soluble solvent preferably contains sugar. Examples of the saccharide include monosaccharides, disaccharides, oligosaccharides (including trisaccharides and tetrasaccharides), polysaccharides, and the like. Specific examples include glucose, mannose, fructose, ribose, xylose, arabinose, galactose, maltose, cellobiose, lactose, sucrose, trehalose, maltotriose, and the like. Here, the polysaccharide means a saccharide in a broad sense, and is used to include a substance that exists widely in nature such as α-cyclodextrin and cellulose. The derivatives of these saccharides are represented by the reducing sugars of the saccharides described above (for example, sugar alcohols [general formula: HOCH ₂ (CHOH) _n CH ₂ OH (where n is an integer of 2 to 5)). Oxidized sugars (eg, aldonic acid, uronic acid, etc.), amino acids, thioic acids, etc. Among these, sugar alcohols are preferred, and specific examples include maltitol, sorbit, and the like.

  The mass ratio of the pigment and the water-soluble solvent has a great influence on the ink ejection stability from the head. If the blending amount of the wetting agent is small even though the pigment solid content is high, the evaporation of water near the ink meniscus of the nozzle may progress and cause ejection failure.

(Surfactant)
As the surfactant, an anionic surfactant, a cationic surfactant, a nonionic surfactant, an amphoteric surfactant or the like can be used alone or in admixture of two or more.

(Anionic surfactant)
Examples of the anionic surfactant include fatty acid salts, alkyl sulfate esters, alkylaryl sulfonates, alkylnaphthalene sulfonates, dialkyl sulfonates, dialkyl sulfosuccinates, alkyl diaryl ether disulfonates, and alkyl phosphates. , Polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl aryl ether sulfate, polyoxyethylene alkyl ether acetate, alkylbenzene sulfonate (eg NH4, Na, Ca etc.), alkyl diphenyl ether disulfonate (eg NH4, Na , Ca, etc.), naphthalene sulfonic acid formalin condensate and its salt, dialkyl succinate sulfonic acid Na salt, polyoxyethylene alkyl phosphate ester salt, glycerol borate fat Esters, polyoxyethylene glycerol fatty acid esters, polyoxyethylene polycyclic phenyl ether sulfate salts (eg NH4, Na, etc.), laurates, polyoxyethylene alkyl ether sulfate salts, oleates, perfluoroalkyl sulfonic acids, per Fluoroalkyl sulfonate, perfluoroalkyl carboxylic acid, perfluoroalkyl carboxylic acid salt, perfluoroalkyl phosphate ester, salt of perfluoroalkyl phosphate ester, polyoxyalkylene ether polymer having perfluoroalkyl ether group in the side chain , Sulfate salt of polyoxyalkylene ether polymer having perfluoroalkyl ether group in side chain, polyoxyalkylene having perfluoroalkyl ether group in side chain Salts of over terpolymer, and the like. Examples of counter ions in the salts of these fluorosurfactants include Li, Na, K, NH ₄ , NH ₃ CH ₂ CH ₂ OH, NH ₂ (CH ₂ CH ₂ OH) ₂ , NH (CH ₂ CH ₂ OH) _{3 and the} like.

(Cationic surfactant)
Examples of the cationic surfactant include alkylamine salts, quaternary ammonium salts, alkylpyridinium salts, alkylimidazolium salts and the like.

(Nonionic surfactant)
Nonionic surfactants include, for example, polyoxyethylene alkyl ether, polyoxyalkylene alkyl ether, polyoxyethylene alkyl aryl ether, polyoxyethylene oxypropylene block copolymer, polyoxyethylene polycyclic phenyl ether, sorbitan fatty acid ester, polyoxyethylene alkyl ether Oxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, glycerin fatty acid ester, polyoxyethylene alkylphenyl ether, polyoxyethylene alkylamine, polyoxyethylene alkylamide, polyoxyethylene fatty acid ester, acetylene glycol, polyoxyethylene alkylamine And nonionic activators such as fluorine and silicon. In particular, examples of the acetylene glycol surfactant include 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, , 5-dimethyl-1-hexyn-3-ol and the like. As the acetylene glycol surfactant, a commercially available product can be used. Examples of the commercially available product include Surfynol 104, 82, 465, 485, and TG manufactured by Air Products (USA).

  Moreover, it is also possible to use the fluorine-type surfactant shown below. For example, Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, S-145 (all manufactured by Asahi Glass Co., Ltd.), Fullrad FC-93, FC-95 , FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (all manufactured by Sumitomo 3M), MegaFuck F-470, F1405, F-474 (all Dainippon Ink Chemical Industries), Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR (all manufactured by DuPont), FT-110, FT-250, FT-251, FT -400S, FT-150, FT-400SW (all manufactured by Neos Co., Ltd.), PF-151N (manufactured by Omninova) and the like.

(Zwitterionic surfactant)
Examples of amphoteric surfactants include alkylbetaines, alkylamine oxides, phosphadylcholines and the like. For example, lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, lauryl dihydroxyethyl betaine, lauryl dimethylamine oxide, myristyl dimethylamine oxide, stearyl dimethylamine oxide, dihydroxyethyl lauryl amine oxide, polyoxyethylene coconut oil alkyldimethylamine Examples thereof include oxide, dimethylalkyl (coconut) betaine, and dimethyllauryl betaine.

(Water-soluble resin / emulsion)
There is no restriction | limiting in particular as said water dispersible resin, Although it can select suitably according to the objective, For example, a condensation type synthetic resin, an addition type synthetic resin, a natural polymer compound, etc. are mentioned. Examples of the condensed synthetic resin include polyester resins, polyurethane resins, polyepoxy resins, polyamide resins, polyether resins, and silicon resins. Examples of the addition type synthetic resin include polyolefin resins, polystyrene resins, polyvinyl alcohol resins, polyvinyl ester resins, polyacrylic acid resins, unsaturated carboxylic acid resins, and the like. Examples of the natural polymer compound include celluloses, rosins, and natural rubber. The water-dispersible resin may be used as a homopolymer, may be used as a copolymer and may be used as a composite resin, and any of a single-phase structure type, a core-shell type, and a power feed type emulsion Can be used.

  As the water-dispersible resin, a resin itself having a hydrophilic group and having a self-dispersibility, or a resin itself having no dispersibility and imparted with a surfactant or a resin having a hydrophilic group can be used. . Among these, an emulsion of resin particles obtained by emulsion and suspension polymerization of an ionomer of a polyester resin or a polyurethane resin or an unsaturated monomer is preferable. In the case of emulsion polymerization of an unsaturated monomer, a resin emulsion is obtained by reacting with water to which an unsaturated monomer, a polymerization initiator, a surfactant, a chain transfer agent, a chelating agent, a pH adjusting agent and the like are added. Therefore, a water-dispersible resin can be easily obtained, and the resin properties can be easily changed, so that desired properties can be easily produced.

  Examples of the unsaturated monomer include unsaturated carboxylic acids, (meth) acrylic acid ester monomers, (meth) acrylic acid amide monomers, aromatic vinyl monomers, vinyl cyano compound monomer Isomers, vinyl monomers, allyl compound monomers, olefin monomers, diene monomers, oligomers having unsaturated carbon, and the like can be used alone or in combination. By combining these monomers, the properties can be flexibly modified, and the properties of the resin can be modified by performing a polymerization reaction or a graft reaction using an oligomer type polymerization initiator.

Examples of the unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid and the like.
Examples of the monofunctional (meth) acrylic acid esters include methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-amyl methacrylate, isoamyl methacrylate, n-hexyl methacrylate, and 2-ethylhexyl methacrylate. Octyl methacrylate, decyl methacrylate, dodecyl methacrylate, octadecyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, glycidyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, dimethylaminoethyl methacrylate, methacryloxyethyl trimethylammonium salt, 3 -Metacry Xylpropyltrimethoxysilane, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-amyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, decyl acrylate, Examples include dodecyl acrylate, octadecyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, glycidyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, dimethylaminoethyl acrylate, and acryloxyethyl trimethyl ammonium salt.

Examples of the polyfunctional (meth) acrylic acid esters include ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, and 1,4-butylene. Glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, polybutylene glycol dimethacrylate, 2,2'-bis (4-methacryloxydiethoxyphenyl) )
Propane, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, polyethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butylene glycol diacrylate, 1,6-hexanediol di Acrylate, neopentyl glycol diacrylate, 1,9-nonanediol diacrylate, polypropylene glycol diacrylate, 2,2′-bis (4-acryloxypropoxyphenyl) propane, 2,2′-bis (4-acryloxy) Diethoxyphenyl) propane trimethylolpropane triacrylate, trimethylolethane triacrylate, tetramethylolmethane triacrylate, ditrimethylolte La acrylate, tetramethylolmethane tetraacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, and the like.

Examples of the (meth) acrylic acid amide monomers include acrylamide, methacrylamide, N, N-dimethylacrylamide, methylenebisacrylamide, 2-acrylamido-2-methylpropanesulfonic acid, and the like.
Examples of the aromatic vinyl monomers include styrene, α-methylstyrene, vinyltoluene, 4-t-butylstyrene, chlorostyrene, vinylanisole, vinylnaphthalene, divinylbenzene, and the like.

Examples of the vinyl cyano compound monomers include acrylonitrile and methacrylonitrile.
Examples of the allyl compound monomers include allyl sulfonic acid or a salt thereof, allylamine, allyl chloride, diallylamine, diallyldimethylammonium salt, and the like.
Examples of the olefin monomers include ethylene and propylene.
Examples of the diene monomers include butadiene and chloroprene.
Examples of the vinyl monomers include vinyl acetate, vinylidene chloride, vinyl chloride, vinyl ether, vinyl ketone, vinyl pyrrolidone, vinyl sulfonic acid or salts thereof, vinyl trimethoxysilane, vinyl triethoxysilane, and the like.

 Examples of the oligomers having unsaturated carbon include styrene oligomers having methacryloyl groups, styrene-acrylonitrile oligomers having methacryloyl groups, methyl methacrylate oligomers having methacryloyl groups, dimethylsiloxane oligomers having methacryloyl groups, and polyesters having acryloyl groups. An oligomer etc. are mentioned.

  The water-dispersible resin has a strong alkalinity and strong acidity, and causes a molecular chain breakage such as dispersion breakage and hydrolysis. Therefore, the pH is preferably 4 to 12, and the pH is preferably miscible with the water-dispersible colorant. 6-11 are more preferable, and 7-10 are still more preferable. The average particle size (D50) of the water-dispersible resin is related to the viscosity of the dispersion. For the same composition, the viscosity at the same solid content increases as the particle size decreases. The average particle diameter (D50) of the water-dispersible resin is preferably 50 nm or more so as not to have an excessively high viscosity when converted into an ink. In addition, when the particle size is several tens of microns, it becomes larger than the nozzle opening of the ink jet head and cannot be used. If particles having a large particle diameter are present in the ink even if they are smaller than the nozzle opening, the discharge property is deteriorated. Therefore, the average particle diameter (D50) is more preferably 200 nm or less, and even more preferably 150 nm or less, in order not to inhibit the ink ejection properties.

(PH adjuster)
The pH adjuster is not particularly limited as long as the pH can be adjusted to 7 to 11 without adversely affecting the prepared inkjet ink, and can be appropriately selected according to the purpose. For example, alcohol Examples thereof include amines, alkali metal hydroxides, ammonium hydroxides, phosphonium hydroxides, and alkali metal carbonates. When the pH exceeds 7 to 11, the amount of the ink jet head or ink supply unit that melts out is large, and problems such as ink deterioration, leakage, and ejection failure may occur.

Examples of the alcohol amines include diethanolamine, triethanolamine, 2-amino-2-ethyl-1,3-propanediol, and the like.
Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, and potassium hydroxide.
Examples of the ammonium hydroxide include ammonium hydroxide, quaternary ammonium hydroxide, quaternary phosphonium hydroxide, and the like.
Examples of the alkali metal carbonate include lithium carbonate, sodium carbonate, and potassium carbonate.

(Other)
The other components are not particularly limited and may be appropriately selected as necessary. For example, antiseptic / antifungal agents, chelating reagents, rust inhibitors, antioxidants, ultraviolet absorbers, oxygen absorbers, light And stabilizers.

(Antiseptic and antifungal agent)
Examples of the antiseptic / antifungal agent include sodium dehydroacetate, sodium sorbate, 2-pyridinethiol-1-oxide sodium, sodium benzoate, sodium pentachlorophenol, and the like.

(Chelating reagent)
Examples of the chelating reagent include sodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, sodium uramil diacetate, and the like.

(anti-rust)
Examples of the rust inhibitor include acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, dicyclohexylammonium nitrite, and benzotriazole.

(Antioxidant)
Examples of the antioxidant include phenol-based antioxidants (including hindered phenol-based antioxidants), amine-based antioxidants, sulfur-based antioxidants, phosphorus-based antioxidants, and the like.
Examples of the phenolic antioxidant (including hindered phenolic antioxidant) include butylated hydroxyanisole, 2,6-di-tert-butyl-4-ethylphenol, stearyl-β- (3,5 -Di-tert-butyl-4-hydroxyphenyl) propionate, 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 4,4′-butylidenebis (3-methyl-6-tert-butylphenol), 3,9-bis [1,1-dimethyl-2- [β- (3-tert-butyl-4-hydroxy-5-methylphenyl) ) Propionyloxy] ethyl] 2,4,8,10-tetrixaspiro [5,5] undecane, 1,1,3-tri (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) Benzene, tetrakis [methylene-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) propionate] methane, and the like.
Examples of the amine-based antioxidant include phenyl-β-naphthylamine, α-naphthylamine, N, N′-di-sec-butyl-p-phenylenediamine, phenothiazine, N, N′-diphenyl-p-phenylenediamine. 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butylphenol, 2,4-dimethyl-6-tert-butyl-phenol, butylhydroxyanisole, 2,2′-methylenebis ( 4-methyl-6-tert-butylphenol), 4,4′-butylidenebis (3-methyl-6-tert-butylphenol), 4,4′-thiobis (3-methyl-6-tert-butylphenol), tetrakis [methylene -3 (3,5-di-tert-butyl-4-dihydroxyphenyl) propionate Methane, 1,1,3-tris (2-methyl-4-hydroxy -5-tert-butylphenyl) butane, and the like.
Examples of the sulfur-based antioxidant include dilauryl 3,3′-thiodipropionate, distearyl thiodipropionate, lauryl stearyl thiodipropionate, dimyristyl 3,3′-thiodipropionate, and distearyl β. , Β′-thiodipropionate, 2-mercaptobenzimidazole, dilauryl sulfide and the like.
Examples of the phosphorus antioxidant include triphenyl phosphite, octadecyl phosphite, triisodecyl phosphite, trilauryl trithiophosphite, trinonylphenyl phosphite, and the like.

(UV absorber)
Examples of the ultraviolet absorber include a benzophenone ultraviolet absorber, a benzotriazole ultraviolet absorber, a salicylate ultraviolet absorber, a cyanoacrylate ultraviolet absorber, and a nickel complex ultraviolet absorber.
Examples of the benzophenone-based ultraviolet absorber include 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-n-dodecyloxybenzophenone, 2,4-dihydroxybenzophenone, and 2-hydroxy-4-methoxybenzophenone. 2,2 ′, 4,4′-tetrahydroxybenzophenone, and the like.
Examples of the benzotriazole ultraviolet absorber include 2- (2′-hydroxy-5′-tert-octylphenyl) benzotriazole, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-4′-octoxyphenyl) benzotriazole, 2- (2′-hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chlorobenzotriazole, and the like.
Examples of the salicylate-based ultraviolet absorber include phenyl salicylate, p-tert-butylphenyl salicylate, p-octylphenyl salicylate, and the like.
Examples of the cyanoacrylate ultraviolet absorber include ethyl-2-cyano-3,3′-diphenyl acrylate, methyl-2-cyano-3-methyl-3- (p-methoxyphenyl) acrylate, and butyl-2- And cyano-3-methyl-3- (p-methoxyphenyl) acrylate.
Examples of the nickel complex ultraviolet absorber include nickel bis (octylphenyl) sulfide, 2,2′-thiobis (4-tert-octylferrate) -n-butylamine nickel (II), 2,2′-thiobis. (4-tert-octylferrate) -2-ethylhexylamine nickel (II), 2,2′-thiobis (4-tert-octylferrate) triethanolamine nickel (II), and the like.

(Adjustment of inkjet ink)
The method of producing an inkjet ink using the pigment (pigment (A)) by which the surface obtained by this invention was coat | covered with resin is shown. The following two production methods can be used for inkjet ink. However, the components constituting the ink-jet ink can be added by any order and method, and are not limited to the two production methods described below.

The first method is a method in which either or both of a pigment dispersion in which the pigment (A) is dispersed and a crosslinked pigment dispersion are prepared and mixed with the components constituting the ink jet ink to obtain an ink jet ink. In this method, the pigment (A) and the components constituting the inkjet ink and, if necessary, the crosslinking agent are directly mixed to obtain the inkjet ink. Any method and apparatus may be used for mixing the pigment (A) and the components constituting the inkjet ink as long as uniform mixing is possible. Specific examples of the apparatus include the following. High speed mixer, homogenizer, planetary mixer, trimix, kneader, extruder, horizontal sand mill, vertical sand mill or / and annular bead mill, paint shaker, ball mill, disperser equipped with ultrasonic oscillator, two roll mill A three roll mill or the like may be mentioned, but the invention is not limited to this.

 EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not particularly limited to the examples. In the examples, “part” is “part by mass”, and “%” is “% by mass”.

(Acid value)
About 1 g of a sample is accurately weighed in an Erlenmeyer flask and dissolved by adding 50 ml of a distilled water / dioxane (mass ratio: distilled water / dioxane = 1/9) mixture. A 0.1 mol / L potassium hydroxide / ethanol solution (titer a) is used for the sample solution by using a potentiometric measuring device (manufactured by Kyoto Electronics Industry Co., Ltd., apparatus name “potentiometric automatic titrator AT-710M”). The amount of potassium hydroxide / ethanol solution (b (mL)) required until the end of titration was measured. The acid value (mgKOH / g) was determined by the following equation as the value of the resin in the dry state.
Acid value (mgKOH / g) = {(5.611 × a × F) / S} / (Nonvolatile content concentration / 100)
However,
S: Sample collection amount (g)
a: Consumption of 0.1 mol / L potassium hydroxide / ethanol solution (ml)
F: Potency of 0.1 mol / L potassium hydroxide / ethanol solution

(Weight average molecular weight (Mw))
The weight average molecular weight (Mw) is a polystyrene measured using TSKgel column (manufactured by Tosoh Corporation) and GPC equipped with RI detector (manufactured by Tosoh Corporation, HLC-8320GPC) using THF as a developing solvent. It is a weight average molecular weight (Mw) in terms of conversion.

(Synthesis of α-olefin copolymer having an acidic group (matrix resin A))
In a reaction vessel equipped with a gas introduction tube, a thermometer, a condenser and a stirrer, 46.2 g of 1-hexene and 53.8 g of maleic anhydride were charged as α-olefin, 10 g of xylene was charged into a flask, and the atmosphere was replaced with nitrogen. Heated and stirred at 130 ° C. Thereto, a mixture of peroxide perbutyl O (NOF Corporation) 1.0 g and xylene 20 g was added dropwise over 2 hours with stirring. Thereafter, the mixture was further stirred for 1 hour while maintaining the temperature at 130 ° C., and the xylene was concentrated under reduced pressure to be completely removed to obtain a copolymer (matrix resin A). The resulting copolymer (matrix resin A) had a weight average molecular weight (Mw) of about 10,000 and an acid value of 615.7 mgKOH / g.

(Α-Olefin copolymer having acidic group (base resins B and C))
Except having changed into the raw material and preparation amount which were described in Table 1, it synthesize | combined like (base resin A), and obtained the copolymer (base resin B and C). The molecular weight was adjusted appropriately by changing the amount of perbutyl O added. Each weight average molecular weight (Mw) and acid value are as described in Table 1.

(Production of α-olefin copolymer (polymer A) having an acidic group)
In a reaction vessel equipped with a gas introduction tube, a thermometer, a condenser, and a stirrer, 32.2 g of the base resin A, 67.8 g of the compound (3) -1 shown in Table 2, and 0.2 g of diazabicycloundecene as a catalyst In addition, the mixture was heated to 130 ° C. with stirring. After 1 hour, the temperature was changed to 110 ° C. and held for another hour, and further changed to 90 ° C. and held for 4 hours to carry out an ester reaction. In the general formula (3), R ₁ = methyl group, A ¹ An α-olefin maleic anhydride copolymer (polymer A) having a graft chain of O═C ₂ H ₄ O, m = 12, and n = 0 was obtained. The obtained copolymer had a weight average molecular weight (Mw) of about 13,000 and an acid value of 99 mgKOH / g.

(Production of α-olefin copolymer having an acidic group (polymers B, C, E))
The copolymer (polymers B, C, E) was obtained in the same manner as (Polymer A) except that the raw materials and amounts charged in Table 2 were changed. Each weight average molecular weight (Mw) and acid value are as described in Table 2.

(Production of α-olefin copolymer having an acidic group (polymer D))
61.7 g of base resin B and 38.3 g of stearylamine are added to a reaction vessel equipped with a gas introduction tube, a thermometer, a condenser, and a stirrer, and the reaction is carried out at a reaction temperature of 180 ° C. for 5 hours in a nitrogen stream while stirring. It was. After completion of the reaction, the content was taken out when heated to obtain an α-olefin copolymer (polymer D) having an acidic group. The weight average molecular weight (Mw) of the obtained copolymer was about 11,000, and the acid value was 79.7 mgKOH / g.

The abbreviations in Table 2 are shown below.
(3) -1: An alcohol in which the right end of the general formula (3) is bonded to a hydrogen atom. In formula (3), R ₁ = methyl group, A ¹ O = C ₂ H ₄ O, m = 12, and n = 0.
(3) -2: An alcohol in which the right end of the general formula (3) is bonded to a hydrogen atom. In the general formula (3), R ₁ = C ₈ H ₁₇ , A ¹ O = C ₂ H ₄ O, A ² O = C ₃ H ₆ O, m = 3, and n = 6.

≪Inkjet ink≫
<Method for Producing Pigment (A) (Wet)>
[Production Example 1]
250 parts of PY12 (“LIONOL YELLOW TCH1205” manufactured by Toyocolor Co., Ltd.) as a pigment, 1250 parts of sodium chloride as a water-soluble inorganic salt, 87.5 parts of polymer A as a resin, and 250 parts of diethylene glycol as a water-soluble organic solvent And kneaded at 80 ° C. for 6 hours. This mixture is put in 7,500 parts of water and allowed to stand for 24 hours, stirred for about 1 hour with a high-speed mixer to form a slurry, filtered and washed repeatedly to remove sodium chloride and water-soluble organic solvent, and the surface is resin. A pigment (coated pigment) (1) coated with the above was obtained. (Solid content 30.5%)

[Production Examples 2-11, Comparative Production Examples 1, 3, 4]
Coated pigments (2) to (12), (14), and (15) were obtained in the same manner as in Production Example 1 except that the compositions shown in Table 3 were changed.

[Comparative Production Example 2]
250 parts of PY12 (“LIONOL YELLOW TCH1205” manufactured by Toyocolor Co., Ltd.) as a pigment, 1250 parts of sodium chloride as a water-soluble inorganic salt, and 250 parts of diethylene glycol as a water-soluble organic solvent are charged into a stainless steel 3L kneader (manufactured by Inoue Seisakusho). The mixture was kneaded at 6 ° C. for 6 hours. The mixture was put in 7,500 parts of water and allowed to stand for 24 hours, and stirred with a high speed mixer for about 1 hour to form a slurry. Filtration and washing were repeated to remove sodium chloride and the water-soluble organic solvent to remove the coated pigment (13 ) (Actually uncoated pigment). (Solid content 30.5%)

Abbreviations in Table 3 are shown below.
Joncryl690: Styrene (meth) acrylic resin (BASF)
DEG: Diethylene glycol NaCl: Sodium chloride

<Method for producing pigment dispersion>
[Production Example 12]
The pigment dispersion (1) was treated when preparing the coated pigment (1), ion-exchanged water and the coated pigment so that the uncoated pigment (pigment (B)) was 15 parts in 100 parts of the pigment dispersion (1). The equivalent amount of dimethylaminoethanol calculated from the amount of resin and acid value is weighed, stirred at a liquid temperature of 70 ° C. for 1 hour with a high speed mixer, and the volatile water is adjusted with ion-exchanged water to give a pigment dispersion (1) 100 parts were obtained. The particle size distribution of the obtained pigment dispersion was evaluated as the particle size distribution of the coated pigment (1). The particle size distribution was measured by diluting with ion-exchanged water using Nanotrac Wave (manufactured by Microtrack Bell). The particle size distribution of the pigment dispersion (1) was d1 = 21 nm, d50 = 104 nm, d99 = 402 nm (volume average particle diameter).

[Production Examples 13 to 22, Comparative Production Examples 5, 7, and 8]
Pigment dispersions (2) to (12), (14), and (15) were obtained in the same manner as in Production Example 12 except that the compositions shown in Table 3 were changed. The particle size distribution of the obtained pigment dispersion was measured in the same manner as in Production Example 12.

[Comparative Production Example 6]
Weigh out 49.6 parts of ion-exchanged water, 1.3 parts of dimethylaminoethanol, and 5.3 parts of polymer A, and stir and mix with a high-speed mixer for 1 hour while heating to 70 ° C. To obtain an aqueous dispersion of polymer A. Weigh out 43.9 parts of the coated pigment (13) (the pigment that is not actually coated) and 56.1 parts of the aqueous dispersion of polymer A, and stir it for 1 hour with a high-speed mixer at a liquid temperature of 70 ° C. Adjustment with ion-exchanged water gave 100 parts of a pigment dispersion (13).

<Evaluation of pigment dispersion>
The following items were evaluated for the obtained pigment dispersion. The evaluation results are shown in Table 4.
(1) Coarse Grain Amount Test The coarse particle amount in the pigment dispersion was evaluated by the passage time of a fixed amount of the pigment dispersion through a 25 mmφ glass fiber filter (manufactured by GF / B GE Healthcare Life Sciences). . When there are many coarse particles, the filter is clogged and the passage time is observed to be long. Further, when there are more coarse particles, the filter is clogged and the entire pigment dispersion cannot be filtered. In general, the filter used for the ink supply path to the inkjet head is larger than 1 μm, and the pigment concentration of inkjet ink is generally lower than that of the pigment dispersion. I can say that. Specific evaluation conditions are shown below. 25mm diameter filter holder (manufactured by ADVANTEC) with a funnel with a 15ml scale and a 25mmφ glass fiber filter (manufactured by GF / B GE Healthcare Life Science) on a suction vessel with a vacuum pump via a cock ). The decompression pump is operated using a cock so that the inside of the suction vessel is not decompressed. 15 g of pigment dispersion is weighed into a funnel. Starting with the opening pressure of the pump and the suction vessel, the time for the total amount of the pigment dispersion to pass through the filter is measured. At this time, the pressure in the suction vessel is 0.05 MPa to 0.07 MPa. When the filtration filter was blocked within 60 seconds and the pigment dispersion did not pass, the amount of the pigment dispersion remaining in the funnel was measured.

 In Table 4, the dispersions of Production Examples (12) to (22) are good coarse particle amount test results, whereas Comparative Production Examples (5) to (8) were blocked in the coarse particle amount test. Pigments (1) to (11) were excellent in dispersibility of coarse particles.

Abbreviations in Table 4 are shown below.
Dimethylaminoethanol: amino alcohol 2 Mabs (manufactured by Nippon Emulsifier Co., Ltd.)

<Inkjet ink production method (1)>
[Example 23]
26.7 parts of pigment dispersion (1) and 73.3 parts of the following diluent A were stirred and mixed at 500 rpm with a high-speed mixer to obtain inkjet ink (1).

(Diluent A)
Glycerin 10.0 parts Triethylene glycol monobutyl ether 15.0 parts Surfynol DF110D (air products Japan antifoam) 0.5 parts Proxel GXL (LONZA antiseptic) 0.2 parts ion-exchanged water 47.6 Part

[Examples 24-35, Comparative Examples 9-15]
Inkjet inks (2) to (20) were obtained in the same manner as in Example 23 except that the compositions shown in Table 5 were changed.

[Comparative Example 16]
26.7 parts of pigment dispersion (1) and 73.3 parts of ion-exchanged water were mixed by stirring at 500 rpm with a high speed mixer to obtain inkjet ink (21) (actually, a dispersion dilution).

<Evaluation of inkjet ink (1)>
The following was evaluated about the obtained inkjet ink. The results are shown in Table 5.

(Particle size distribution stability)
The particle size distribution was measured by diluting with ion-exchanged water using the Nanotrac Wave (manufactured by Microtrack Bell) (volume average particle diameter). Furthermore, after the ink-jet ink was stored in a thermostat at 70 ° C. for 1 week and accelerated over time, the particle size distribution was measured in the same manner to determine the rate of change. The evaluation criteria are as follows.
○: Change rate of particle size distribution (D50) before and after storage at 70 ° C. for 1 week is less than ± 10% (good)
Δ: Change rate of particle size distribution (D50) before and after storage at 70 ° C. for 1 week ± 10% or more and less than ± 20% (no problem in practical use)
X: Particle size distribution (D50) change rate before and after storage at 70 ° C. for 1 week is ± 20% or more (defect)

(Viscosity stability)
The viscosity was measured using an E-type viscometer (“ELD type viscometer” manufactured by Toki Sangyo Co., Ltd.) at 25 ° C. under the condition of a rotational speed of 20 rpm. Further, after the inkjet ink was stored in a thermostat at 70 ° C. for 1 week and accelerated with time, the viscosity was measured in the same manner to determine the rate of change. The evaluation criteria are as follows.
○: Viscosity change rate before and after storage at 70 ° C. for 1 week is less than ± 10% (good)
Δ: Viscosity change rate before and after storage at 70 ° C. for 1 week ± 10% or more and less than ± 20% (no problem in practical use)
×: Viscosity change rate before and after storage at 70 ° C. for 1 week is ± 20% or more (defect)

(Dischargeability)
Inkjet ink was filled in an inkjet printer equipped with an inkjet head having a piezo element in an environment of 25 ° C., and 30 sheets were continuously printed on copy paper (Xerox 4024) to observe missing dots. Regarding the percentage of the number of missing nozzles with respect to all nozzles, 0 is indicated for 0%, Δ for more than 0 and 5% or less, and × for more than 5%. If it is more than Δ, it can be used, but ○ is desirable.

(water resistant)
Inkjet ink is filled in an inkjet printer equipped with an inkjet head having a piezo element in an environment of 25 ° C., and recording is performed using cyan, magenta, yellow, black, orange, green, and violet ink on copy paper (Xerox 4024). Then, the recorded matter was immersed in tap water under the conditions of an air temperature of 25 ° C. and a humidity of 50%, and bleeding of the recorded matter was observed. If the recorded material does not bleed even if it is immersed immediately after recording for 1 hour, △ if it is immersed immediately after recording and bleeds within 1 hour, or if it is immersed immediately after recording, the recorded material bleeds immediately. The thing was set as x. If it is more than Δ, it can be used, but ○ is desirable.

 In Table 5, the ink-jet inks of Examples 23 to 35 are superior in storage stability of viscosity and particle size distribution as compared with Comparative Examples 9 to 11, and are ejectable as compared with Comparative Examples 9, 10, and 13-15. Was excellent. Furthermore, the printed matter printed using the inkjet inks of Examples 23 to 35 was excellent in water resistance as compared with Comparative Examples 9, 10, and 12. In Comparative Example 16, water resistance was not evaluated because it was not possible to produce a recorded matter because it could not be ejected by an ink jet printer equipped with an ink jet head having a piezoelectric element. Furthermore, in Examples 28, 29, 31, 32, and 34, particularly good results were obtained in terms of water resistance. This is presumably because the length of the graft chain was long and the hydrophobicity was increased.

About the dilution liquid in Table 5, it shows below.
(Diluent A)
Glycerin 10.0 parts Triethylene glycol monobutyl ether 15.0 parts Surfynol DF110D (air products Japan antifoam) 0.5 parts Proxel GXL (LONZA antiseptic) 0.2 parts ion-exchanged water 47.6 Part

(Diluent B)
Glycerol 10.0 parts Diethylene glycol monobutyl ether 15.0 parts Surfinol DF110D (Air Products Japan antifoam) 0.5 parts Proxel GXL (LONZA antiseptic) 0.2 parts Ion-exchanged water 47.6 parts

(Diluent C)
Glycerol 10.0 parts Ethylene glycol monoethyl ether 15.0 parts Surfinol DF110D (air products Japan antifoam) 0.5 parts Proxel GXL (LONZA antiseptic) 0.2 parts ion-exchanged water 47.6 Part

(Diluent D)
Glycerin 10.0 parts 1,3-propanediol 15.0 parts Surfinol DF110D (air products Japan antifoam) 0.5 parts Proxel GXL (LONZA antiseptic) 0.2 parts ion-exchanged water 47. 6 copies

(Diluent E)
Glycerin 10.0 parts Triethylene glycol 15.0 parts Surfinol DF110D (air products Japan antifoam) 0.5 parts Proxel GXL (LONZA antiseptic) 0.2 parts ion-exchanged water 47.6 parts

(Diluent F)
Glycerin 25.0 parts Surfinol DF110D (air products Japan antifoam) 0.5 parts Proxel GXL (LONZA antiseptic) 0.2 parts ion-exchanged water 47.6 parts

<Method for producing crosslinked dispersion>
[Production Example 36]
Treated when preparing the coated pigment (1), ion-exchanged water, and coated pigment so that the uncoated pigment (pigment (B)) is 20 parts of 100 parts of the pigment dispersion (1 ′). The equivalent amount of potassium hydroxide calculated from the amount of resin and acid value was weighed, stirred at a liquid temperature of 70 ° C. for 1 hour with a high speed mixer, and the volatilized water was adjusted with ion-exchanged water to prepare a pigment dispersion (1 ') 100 parts were obtained. 2.45 parts of Denacol EX321 (epoxy crosslinking agent, manufactured by Nagase ChemteX, non-volatile content: 100 g, epoxy equivalent: 140 g / eq) as a crosslinking agent was added to 100 parts of the pigment dispersion (1 ′) and stirred at 70 ° C. for about 2 hours Then, the evaporated water was adjusted with ion exchange water to obtain a crosslinked pigment dispersion (1). Further, the cross-linked pigment dispersion (1) is adjusted with ion-exchanged water so that the uncoated pigment (pigment (B)) out of 100 parts of the cross-linked pigment dispersion (1) is 15 parts. 100 parts of pigment dispersion (1) were obtained.

[Production Examples 37 to 42]
Crosslinked pigment dispersions (2) to (7) were obtained in the same manner as in Example 37 except that the composition was changed to the composition shown in Table 6.

[Production Examples 43 to 45]
A pigment dispersion was prepared in the same manner as in Production Example 12 except that dimethylaminoethanol was changed to potassium hydroxide to obtain crosslinked pigment dispersions (8) to (10) (however, they were not actually crosslinked).

Abbreviations in Table 6 are shown below.
Denacol EX321: manufactured by Nagase ChemteX, epoxy crosslinking agent, non-volatile content: 100%, epoxy equivalent: 140 g / eq

<Method for producing inkjet ink (2)>
The solvent for preparing the inkjet ink (2) is difficult to obtain stability, but stability can be obtained by using a crosslinking agent in combination.
[Example 46]
In obtaining 100 parts of the inkjet ink, the crosslinked pigment dispersion (1), 16.0 parts of triethylene glycol monobutyl ether, 16.0 parts of diethylene glycol monobutyl ether, Nord DF110D (air products Japan antifoam) 0.5 parts, Proxel GXL (LONZA antiseptic) 0.2 parts, ion-exchanged water 63.3 parts with high speed mixer, mixed at 500 rpm Inkjet ink (1) was obtained.

[Examples 47 to 55]
Inkjet inks (2) to (10) in the same manner as in Example 46 except that the crosslinked pigment dispersions shown in Table 7 were changed (however, the crosslinked pigment dispersions (8) to (10) were not crosslinked). Got.

<Evaluation of inkjet ink (2)>
The following was evaluated about the obtained inkjet ink (2). The results are shown in Table 7.

(Particle size distribution stability)
The particle size distribution was measured by diluting with ion-exchanged water using the Nanotrac Wave (manufactured by Microtrack Bell) (volume average particle diameter). Furthermore, after the ink-jet ink was stored in a thermostat at 70 ° C. for 1 week and accelerated over time, the particle size distribution was measured in the same manner to determine the rate of change. The evaluation criteria are as follows.
○: Change rate of particle size distribution (D50) before and after storage at 70 ° C. for 1 week is less than ± 10% (good)
Δ: Change rate of particle size distribution (D50) before and after storage at 70 ° C. for 1 week ± 10% or more and less than ± 20% (no problem in practical use)
X: Particle size distribution (D50) change rate before and after storage at 70 ° C. for 1 week is ± 20% or more (defect)

(Viscosity stability)
The viscosity was measured using an E-type viscometer (“ELD type viscometer” manufactured by Toki Sangyo Co., Ltd.) at 25 ° C. under the condition of a rotational speed of 20 rpm. Further, after the inkjet ink was stored in a thermostat at 70 ° C. for 1 week and accelerated with time, the viscosity was measured in the same manner to determine the rate of change. The evaluation criteria are as follows.
○: Viscosity change rate before and after storage at 70 ° C. for 1 week is less than ± 10% (good)
Δ: Viscosity change rate before and after storage at 70 ° C. for 1 week ± 10% or more and less than ± 20% (no problem in practical use)
×: Viscosity change rate before and after storage at 70 ° C. for 1 week is ± 20% or more (defect)

 In Table 7, Examples 46 to 52 were excellent in the viscosity and the stability of the particle size distribution after making the ink jet ink by using a crosslinking agent. On the other hand, since Examples 53 to 55 did not use a crosslinking agent, it was not possible to obtain sufficient storage stability after acceleration of the particle size distribution and viscosity.

Claims (7)

Including a pigment whose surface is coated with a resin, a water-soluble organic solvent, a basic substance (except for the case of the resin), and water,
The resin is an α-olefin copolymer having an acidic group,
A water-based ink wherein the water-soluble organic solvent is an alcohol alkyl ether. The water-based ink according to claim 1, wherein the resin is an α-olefin copolymer having a graft chain and an acidic group. The water-based ink according to claim 1 or 2, wherein the graft chain includes a partial structure selected from the group consisting of structures represented by the following general formulas (1) to (3).
General formula (1)

[In General Formula (1), R ₁ represents a substituted C _{6 to} C ₃₀ alkyl group, an optionally substituted alicyclic structure, or an optionally substituted phenyl group]
General formula (2)

[In General Formula (2), R ₁ and R ₂ are each independently a hydrogen atom, an optionally substituted C ₁ -C ₃₀ alkyl group, an optionally substituted alicyclic structure, or a substituted group. Represents an optionally substituted phenyl group. However, when _one of R ₁ and R ₂ is a hydrogen atom, the other is not a hydrogen atom. ]
General formula (3)

[In General Formula (3), R ₁ represents a hydrogen atom, an alkyl group having 6 to 20 carbon atoms, or a phenyl group optionally substituted with an alkyl group having 1 to 9 carbon atoms, and A ¹ O and A ² O independently represents an alkyleneoxy group having 1 to 6 carbon atoms, m and n represent an average addition mole number of the alkyleneoxy group, each independently represents an integer of 0 to 100, and m + n is 1 or more. ] The water-based ink according to any one of claims 1 to 3, wherein the resin coating amount of the pigment is 10 to 50 parts by mass with respect to 100 parts by mass of the pigment (B) before coating. The water-based ink according to claim 1, wherein the pigment is an azo pigment. Furthermore, the water-based ink of any one of Claims 1-6 containing a crosslinking agent. Printed matter provided with the film containing the water-based ink according to any one of claims 1 to 6.