JP2005263875A - Ink composition and inkjet recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal, piezoelectric, electrolytic or acoustic inkjet recording ink which is equipped with handleability, odor and safety, is excellent in dispersion stability and shelf stability of a dispersed substance, is excellent in discharge stability, shows no paper dependence, is excellent in color development and color tone (hue), is excellent in ink permeation especially when using a photographic quality paper, is excellent in water resistance, especially image permanence (especially light fastness and ozone resistance) and resistance to scuffing after recording and enables high-density high-quality recording, and an inkjet recording method using the ink. <P>SOLUTION: The ink composition excellent in permeation etc. is prepared by dispersing a particulate containing an oil-soluble dyestuff having an oxidation potential nobler than 1.0 V (vs SCE) and a dispersible polymer in an aqueous medium using a nonionic surfactant. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ink composition containing a water-based fine particle dispersion containing a dispersible polymer and an oil-soluble dye, and an ink jet recording method using the ink composition.

  In recent years, with the spread of computers, ink jet printers are widely used not only in offices but also in homes for printing on paper, films, cloths, and the like. As inks for inkjet recording, oil-based inks, water-based inks, and solid inks are known, but among these, water-based inks are advantageous in terms of manufacturability, handleability, odor, safety, etc. Water-based ink has become mainstream.

However, since many of the water-based inks use water-soluble dyes that dissolve in a molecular state, there are advantages that transparency and color density are high, but the water resistance is poor because the dyes are water-soluble. When printing on paper, bleeding (bleeding) occurs and the printing quality is remarkably deteriorated, light resistance is poor, and furthermore, a recording paper (hereinafter referred to as “photo quality paper”) provided with an ink receiving layer containing porous inorganic fine particles on the surface. However, the image storage stability is significantly deteriorated due to the influence of an oxidizing gas (SO _x , NO _x , ozone, etc.).

Therefore, water-based inks using pigments and disperse dyes have been proposed for the purpose of solving the above problems (see Patent Document 1).
However, in the case of these water-based inks, although the water resistance is improved to some extent, it is difficult to say that it is sufficient, and the storage stability of the dispersion of pigments and disperse dyes in the water-based ink is lacking, which causes clogging at the ink discharge port. There are problems such as easy. Furthermore, in photographic image quality paper, inks using the pigments and dyes have poor permeability, and there is a problem that the pigments and dyes are easily peeled off from the surface when rubbed by hand.

On the other hand, a method of encapsulating an oil-soluble dye in a polymer has been proposed (for example, see Patent Documents 2 and 3). However, in the case of ink jet ink obtained by this method, the color tone is insufficient, the color reproducibility is not sufficient, especially the image durability due to an oxidizing gas or the like is not sufficient, and further printing on photographic quality paper is possible. In such a case, the scratch resistance is not sufficient.
Further, inks excellent in colorability and scratch resistance have been proposed by introducing a salt-forming group and a polyalkylene oxide group into the polymer (see, for example, Patent Document 4), but the scratch resistance by fingers is good. However, a high level of scratch resistance such as an eraser rub is insufficient.
Furthermore, a method for improving color tone and scratch resistance by using a high-boiling organic solvent and a dye has been proposed (see, for example, Patent Document 5), but this is not necessary when high level image durability is required. It was enough.

As described above, it has handleability, odor, and safety, and the dispersed particle size is small, and the dispersion is excellent in dispersion stability and storage stability. Therefore, when applied to ink, at the tip of the nozzle. No clogging, excellent ejection stability, no paper dependency, excellent color development and color tone (hue), excellent ink penetration even when using the above photographic quality paper, water resistance after printing, especially image storage stability At present, an ink composition that is a fine particle dispersion that is excellent in (especially light resistance and ozone resistance) and scratch resistance and enables high-quality recording at a high concentration has not yet been provided.
JP-A-56-157468 JP 58-45272 A JP 62-241901 A Japanese Patent Laid-Open No. 2001-123097 JP 2001-262018 A

  The present invention has been made in view of the above problems, and its purpose is to provide handling properties, odor, and safety, as well as to reduce the particle size of the dispersed particles, and to provide dispersion stability and storage stability of the dispersion. Excellent, no clogging at the nozzle tip, excellent ejection stability, no paper dependency, excellent color development and color tone (hue), especially excellent ink penetration even when using photo quality paper, water resistance after recording , Especially image storability (especially light resistance and ozone resistance), scratch resistance, high density and high image quality recording, thermal, piezoelectric, electrolytic or acoustic ink jet recording ink and this ink were used It is to provide an ink jet recording method.

In view of such circumstances, the present inventors conducted extensive research and found that fine particles containing an oil-soluble dye and a dispersible polymer whose oxidation potential is nobler than 1.0 V (vs SCE) are nonionic surfactant. The present invention has been completed by finding that an ink dispersed in an aqueous medium using an agent can solve the above problems.
That is, the present invention provides the following.

  <1> An ink characterized in that fine particles containing an oil-soluble dye having a oxidation potential nobler than 1.0 V (vs SCE) and a dispersible polymer are dispersed in an aqueous medium by a nonionic surfactant. Composition.

<2> The ink composition according to <1>, wherein an anionic surfactant is further used in addition to the nonionic surfactant.

  <3> The ink composition according to <1> or <2>, wherein the nonionic surfactant has an HLB of 8 or more.

  <4> The ink composition according to <1>, <2>, or <3>, wherein the nonionic surfactant is used in an amount of 0.01 to 1.0 times the weight of the oil-soluble dye.

  <5> The ink composition according to any one of <1> to <4>, further comprising one or more selected from alcohols, polyhydric alcohols, and water-soluble glycol ethers.

  <6> An inkjet recording method including a step of recording an image on a recording material using the ink composition according to any one of <1> to <5>.

  <7> The recording method according to <6>, wherein the recording material is a recording material having a porous ink receiving layer containing inorganic fine particles.

  The ink composition of the present invention has handleability, odor, and safety, and has a small dispersed particle size, excellent dispersion stability and storage stability of the dispersion, and discharge without clogging at the nozzle tip. Excellent stability, no paper dependency, excellent color development and color tone (hue), especially excellent ink penetration even when using photographic quality paper, water resistance after printing, image storage stability (especially light resistance, It has excellent ozone resistance and scratch resistance, and enables high-density, high-quality inkjet recording.

[Ink composition]
The ink composition of the present invention is obtained by dispersing fine particles including an oil-soluble dye having an oxidation potential nobler than 1.0 V (vs SCE) and a dispersible polymer in an aqueous medium with a nonionic surfactant. The ink composition may further contain a hydrophobic high-boiling organic solvent having a boiling point of 150 ° C. or higher. The ink composition of the present invention is a so-called emulsification in which the oil-soluble dye, the polymer, and optionally a hydrophobic high-boiling organic solvent and other colorants are dispersed as oil droplets on fine particles in an aqueous medium. It is in a distributed state.
In the present invention, the “aqueous medium” means a mixture of water or a mixture of water and a small amount of a water-miscible organic solvent with additives added as necessary.

(Dispersible polymer)
The dispersible polymer used in the present invention is preferably a hydrophobic polymer alone or a polymer having a hydrophobic polymer portion and a hydrophilic polymer portion. The disposition of the hydrophobic polymer part and the hydrophilic polymer part in the dispersible polymer is optional, but the hydrophilic polymer part is located at the end or side chain of the polymer, for example, a graft copolymer in which the side chain is a hydrophilic polymer part A block copolymer having a hydrophilic polymer moiety at the end is preferred. The dispersible polymer used in the present invention may be a conventionally known polymer such as a vinyl polymer or a condensation polymer (polyurethane, polyester, polyamide, polyurea, polycarbonate), but a vinyl polymer that can easily control the structure of the polymer is preferable.
Here, the hydrophobic polymer portion is a polymer portion having a property that is insoluble in water and does not decompose when a polymer composed of a hydrophobic portion is formed, and the molecular weight (Mw) is smaller in order to further improve ink permeability. Is preferred. That is, Mw is preferably 10,000 or less, and more preferably 5000 or less. The glass transition temperature (Tg) is preferably 30 ° C. or lower.

The following are mentioned as an example of the monomer which comprises a hydrophobic polymer site | part.
Acrylic acid esters and methacrylic acid esters (the group at the end of the ester bond includes an aliphatic group which may have a substituent and an aromatic group which may have a substituent. As, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, amyl group, hexyl group, 2-ethylhexyl group, tert-octyl group 2-chloroethyl group, 4-bromobutyl group, cyanoethyl group, cyclohexyl group, benzyl group, butoxymethyl group, 3-methoxybutyl group, 2- (2-methoxyethoxy) ethyl group, 2- (2-butoxyethoxy) ethyl group 2,2,2-tetrafluoroethyl group, 1H, 1H, 2H, 2H perfluorodecyl group, 4-butylphenyl group, phenyl group, 2,4,5-tetramethyl (A tilphenyl group, 4-chlorophenyl group, etc. are mentioned.)

  Acrylamides, methacrylamides, specifically, N-monosubstituted acrylamides, N-disubstituted acrylamides, N-monosubstituted methacrylamides, N-disubstituted methacrylamides (wherein the substituent has a substituent) An aliphatic group which may optionally be substituted and an aromatic group which may have a substituent, examples of which include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, Isobutyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, 2-ethylhexyl group, tert-octyl group, cyclohexyl group, benzyl group, alkoxymethyl group, alkoxyethyl group, 4-butylphenyl group, phenyl Group, 2,4,5-tetramethylphenyl group, 4-chlorophenyl group, etc.).

  Examples of olefins include dicyclopentadiene, ethylene, propylene, 1-butene, 1-pentene, vinyl chloride, vinylidene chloride, isoprene, chloroprene, butadiene, and 2,3-dimethylbutadiene.

  Styrenes, specifically styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, isopropyl styrene, chloromethyl styrene, methoxy styrene, acetoxy styrene, chloro styrene, dichloro styrene, bromo styrene, vinyl benzoic acid methyl ester Etc.

  Examples of vinyl ethers include methyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, and methoxy vinyl ether.

  Other monomers include butyl crotonate, hexyl crotonate, dimethyl itaconate, dibutyl itaconate, diethyl maleate, dimethyl maleate, dibutyl maleate, diethyl fumarate, dimethyl fumarate, methyl vinyl ketone, phenyl vinyl ketone, methoxyethyl Vinyl ketone, N-vinyl oxazolidone, N-vinyl pyrrolidone, vinylidene chloride, methylene malonnitrile, vinylidene, diphenyl-2-acryloyloxyethyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, dibutyl-2-acryloyloxyethyl phosphate Fate, dioctyl-2-methacryloyloxyethyl phosphate, and the like.

  Monomers constituting the hydrophobic polymer site include ester groups that are unsubstituted aliphatic groups, alkyl-substituted aromatic groups, unsubstituted aromatic groups, acrylates and methacrylates, and substituents. N-monosubstituted acrylamide, N-disubstituted acrylamide, N-monosubstituted methacrylamide, and N-disubstituted methacrylamide in which is an unsubstituted aliphatic group, alkyl-substituted phenyl group, or phenyl group. Acrylic esters and methacrylic esters in which the group is an aliphatic group having 1 to 20 carbon atoms, an alkyl-substituted aromatic group having 7 to 30 carbon atoms, or an unsubstituted aromatic group are more preferable, and a group at the end of an ester bond Is an aliphatic group having 2 to 20 carbon atoms, an alkyl-substituted phenyl group having 7 to 30 carbon atoms, an acrylate ester having a phenyl group, Tacrylic acid esters are more preferred, acrylic acid esters and methacrylic acid esters in which the terminal group of the ester bond is an aliphatic group having 2 to 20 carbon atoms, further preferred are hexyl methacrylate, 2-ethylhexyl methacrylate, butyl acrylate, Isobutyl acrylate, s-butyl acrylate, ethyl acrylate, propyl acrylate, hexyl acrylate, and 2-ethylhexyl acrylate are more preferable, and hexyl methacrylate, butyl acrylate, isobutyl acrylate, s-butyl acrylate, propyl acrylate, and hexyl acrylate are particularly preferable.

  As long as the glass transition point (Tg) of the polymer is 30 ° C. or less, the hydrophobic polymer portion may use one raw material or may have various purposes (for example, solubility and compatibility with oil-soluble dyes). For adjusting the stability of the dispersion).

The hydrophilic polymer part is a polymer part having a property of dissolving in water when a polymer composed of a hydrophilic polymer part is formed. The hydrophilic polymer portion may be any of cationic, anionic, nonionic or a mixed type thereof, but anionic, nonionic or a mixed type thereof is preferable.
Examples of the cationic polymer moiety include a polymer having a cationic dissociation group such as a tertiary amino group and pyridine. Examples of the anionic polymer moiety include a polymer having an anionic dissociation group such as carboxylic acid and sulfonic acid. Examples of the ionic polymer portion include a polymer containing a nonionic dispersible group such as an ethyleneoxy group, a hydroxyl group, and a pyrrolidone group.

  Examples of the monomer constituting the hydrophilic polymer or the structural unit of the polymer include monomers having an acid such as a carboxyl group and a sulfo group (acrylic acid, methacrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, 2-carboxyethyl Acrylates, etc.), acrylic acid esters and methacrylic acid esters having a hydrophilic substituent at the ester site (hydrophilic substituents such as hydroxyl group, carboxyl group, amino group, etc.), acrylamide, methacrylamide, N-mono Examples include substituted acrylamides, N-disubstituted acrylamides, N-monosubstituted methacrylamides, N-disubstituted methacrylamides, vinyl pyrrolidone, polyethylene oxide moieties, polyvinyl alcohol moieties, and polyhydric alcohol moieties such as sugar and glycerin.

  Among these, acrylic acid and methacrylic acid, 2-carboxyethyl acrylate, acrylic acid esters and methacrylic acid esters having a hydroxyl group (as examples of the terminal group of the ester bond having a hydroxyl group, a 2-hydroxyethyl group, 2 N-monosubstituted acrylamide, N-disubstituted acrylamide, N-monosubstituted methacrylamide, N-disubstituted methacrylamide whose total number of carbon atoms of the substituents on nitrogen is 1-4. , Polyethylene oxide moieties, polyvinyl alcohol moieties, and polyhydric alcohol moieties such as sugar and glycerin are preferred. Particularly, acrylic acid, methacrylic acid, 2-carboxyethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2, 3 -Dihydr Xylpropyl acrylate and 2,3-dihydroxypropyl methacrylate are more preferable, and acrylic acid and methacrylic acid, 2-hydroxyethyl acrylate, 2,3-dihydroxypropyl acrylate, 2,3-dihydroxypropyl methacrylate, polyethylene oxide sites, polyvinyl Alcohol moieties are preferred, and 2,3-dihydroxypropyl acrylate, 2,3-dihydroxypropyl methacrylate, and polyethylene oxide moieties are also preferred.

  As long as the hydrophilic polymer portion functions as a hydrophilic portion, one kind of raw material may be used, and various purposes (the stability of the dispersion in each aqueous medium, the dissolution of the polymer for producing the dispersion). Two or more of them may be used for the adjustment of the property.

  The content of the hydrophobic polymer portion and the hydrophilic polymer portion in the dispersible polymer used in the present invention is arbitrary depending on the respective properties (for example, the difference in water solubility of the hydrophilic polymer portion, the difference in hydrophobicity of the hydrophobic polymer portion). The hydrophobic polymer part is preferably 60 to 90% by weight, the hydrophilic polymer part is preferably 10 to 40% by weight, the hydrophobic polymer part is 60 to 85% by weight, and the hydrophilic polymer part is 15 to 15% by weight. 40 mass% is more preferable, 60-80 mass% of a hydrophobic polymer site | part and 20-40 mass% of a hydrophilic polymer site | part are especially preferable.

  When the hydrophilic polymer portion has an anionic dissociable group, the content of the dissociable group is preferably 0.1 to 3.0 mmol / g, and more preferably 0.2 to 2.0 mmol / g. When the content of the dissociable group is small, the self-emulsifying property of the polymer is small.

  Further, when the dissociable group is an anionic dissociable group, it may be an alkali metal (for example, Na, K etc.) or a salt of ammonium ion, and when it is a cationic dissociable group, an organic acid (For example, acetic acid, propionic acid, methanesulfonic acid) and salts of inorganic acids (hydrochloric acid, sulfuric acid, etc.) may be used.

  The weight average molecular weight (Mw) of the dispersible polymer used in the present invention is preferably 500 to 200000, and particularly preferably 1000 to 50000. When the molecular weight is less than 500, it tends to be difficult to obtain a stable ink composition. When the molecular weight is more than 200000, the solubility in an organic solvent is deteriorated, or the clay in the organic solvent solution is increased and separated. It tends to be difficult.

  Specific examples of the dispersible polymer used in the present invention are listed. The ratio in parentheses means the mass ratio. The present invention is not limited to these specific examples.

PA-1) Methacrylate copolymer of butyl acrylate / polyethylene glycol monomethyl ether (ethyleneoxy chain repeat number about 23) (60:40)
PA-2) Hexyl methacrylate / 2,3-dihydroxypropyl acrylate copolymer (85:15)
PA-3) Methacrylic acid ester copolymer of isobutyl acrylate / polyethylene glycol monomethyl ether (ethyleneoxy chain repeat number about 45) (70:30)
PA-4) s-butyl acrylate / 2,3-dihydroxypropyl methacrylate copolymer (82:18)
PA-5) Methacrylic acid ester copolymer of hexyl methacrylate / 2-carboxyethyl acrylate / polyethylene glycol monomethyl ether (ethyleneoxy chain repeat number about 23) (70:10:20)
PA-6) Macromonomer copolymer having butyl acrylate / poly (2,3-dihydroxypropyl acrylate) moiety (80:20)
PA-7) Methacrylate ester copolymer of butyl acrylate / isobutyl acrylate / polyethylene glycol monomethyl ether (ethyleneoxy chain repeat number about 9) (50:20:30)
PA-8) Macromonomer copolymer with butyl acrylate / poly (vinyl alcohol) moiety (80:20)
PA-9) Macromonomer copolymer containing butyl acrylate / acrylic acid as a structural unit (80:20)
PA-10) Methacrylate copolymer of butyl acrylate / polyethylene glycol monomethyl ether (ethyleneoxy chain repeat number about 23) / methacrylate ester copolymer of polyethylene glycol monomethyl ether (ethyleneoxy chain repeat number about 9) (70 : 20: 10)
PA-11) Butyl acrylate / 1H, 1H, 2H, 2H-perfluorohexyl acrylate / polyethylene glycol monomethyl ether (ethyleneoxy chain repeat number about 23) methacrylate ester copolymer (70:10:20)
PA-12) A methacrylic acid ester copolymer (75: 5: 20) of a macromonomer / polyethylene glycol monomethyl ether having a butyl acrylate / poly (dimethylsiloxane) moiety (ethyleneoxy chain repeat number of about 23)
PA-13) Butyl acrylate / t-butyl acrylamide copolymer (50:50)

-Oil-soluble dye-
The oil-soluble dye used in the present invention means a pigment that is substantially insoluble in water. More specifically, it means that the solubility in water at 25 ° C. (the mass of the dye that can be dissolved in 100 g of water) is 1 g or less, preferably 0.5 g or less, more preferably 0.1 g or less. .
Therefore, the oil-soluble dye means a so-called water-insoluble oil-soluble dye.

Further, it is desirable that the oxidation potential is noble (high) in order to improve fading, particularly resistance to oxidizing substances such as ozone and curing characteristics. For this reason, the oxidation potential of the oil-soluble dye used in the present invention needs to be nobler than 1.0 V (vs SCE). The oxidation potential is preferably higher, the oxidation potential is preferably higher than 1.1 V (vs SCE), more preferably higher than 1.2 V (vs SCE), and higher than 1.3 V (vs SCE). Particularly preferred.
The oxidation potential is described in paragraphs [0049] to [0051] of JP-A-2002-309118.

The oil-soluble dye preferably has a melting point of 200 ° C. or lower, more preferably has a melting point of 150 ° C. or lower, and still more preferably has a melting point of 100 ° C. or lower. By using an oil-soluble dye having a low melting point, the precipitation of dye crystals in the ink composition is suppressed, and the storage stability of the ink composition is improved.
In the ink composition of the present invention, the oil-soluble dye may be used singly or in combination of several kinds. In addition, other water-soluble dyes, disperse dyes, pigments, and other colorants may be contained as necessary as long as the effects of the present invention are not impaired.
Moreover, a conventionally well-known compound (dye) can be used for an oil-soluble dye. Specific examples include the dyes described in paragraphs [0023] to [0053] of JP-A No. 2002-114930.

  The yellow oil-soluble dye used in the present invention is preferably an oil-soluble dye having a structure represented by the general formula (Y-I). The oil-soluble dye of the general formula (Y-I) may be used not only for yellow but also for any color ink such as black ink, green ink, and red ink.

A-N = NB General Formula (Y-I)

  In the above general formula (Y-I), A and B each independently represents a heterocyclic group which may have a substituent. The heterocyclic ring is preferably a heterocyclic ring composed of a 5-membered ring or a 6-membered ring, and may be a monocyclic structure or a polycyclic structure in which two or more rings are condensed. It may be a ring or a non-aromatic heterocyclic ring. As a hetero atom constituting the heterocyclic ring, a nitrogen atom, an oxygen atom and a sulfur atom are preferable.

  Examples of the heterocyclic ring represented by A include 5-pyrazolone, pyrazole, oxazolone, isoxazolone, barbituric acid, pyridone, rhodanine, pyrazolidinedione, pyrazolopyridone, meldrum acid, and heterocyclic aromatic rings, A condensed heterocyclic ring in which the heterocyclic ring is condensed is preferable. Among these, 5-pyrazolone, 5-aminopyrazole, pyridone and pyrazoloazoles are preferable, and 5-aminopyrazole, 2-hydroxy-6-pyridone and pyrazolotriazole are particularly preferable.

  The heterocyclic ring represented by B includes pyridine, pyrazine, pyrimidine, pyridazine, triazine, quinoline, isoquinoline, quinazoline, cinnoline, phthalazine, quinoxaline, pyrrole, indole, furan, benzofuran, thiophene, benzothiophene, pyrazole, imidazole, benzo Preferable examples include imidazole, triazole, oxazole, isoxazole, benzoxazole, thiazole, benzothiazole, isothiazole, benzoisothiazole, thiadiazole, benzisoxazole, pyrrolidine, piperidine, piperazine, imidazolidine and thiazoline. Of these, pyridine, quinoline, thiophene, benzothiophene, pyrazole, imidazole, benzimidazole, triazole, oxazole, isoxazole, benzoxazole, thiazole, benzothiazole, isothiazole, benzoisothiazole, thiadiazole, and benzoisoxazole are preferable. Thiophene, pyrazole, thiazole, benzoxazole, benzisoxazole, isothiazole, imidazole, benzothiazole, thiadiazole are more preferable, and pyrazole, benzothiazole, benzoxazole, imidazole, 1,2,4-thiadiazole, 1,3,4 -Thiadiazole is particularly preferred.

  Substituents substituted for A and B are halogen atoms, alkyl groups, cycloalkyl groups, aralkyl groups, alkenyl groups, alkynyl groups, aryl groups, heterocyclic groups, cyano groups, hydroxyl groups, nitro groups, alkoxy groups, aryls. Oxy group, silyloxy group, heterocyclic oxy group, acyloxy group, carbamoyloxy group, alkoxycarbonyloxy group, aryloxycarbonyloxy, amino group, acylamino group, aminocarbonylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, Sulfamoylamino group, alkyl and arylsulfonylamino group, mercapto group, alkylthio group, arylthio group, heterocyclic thio group, sulfamoyl group, alkyl and arylsulfinyl group, alkyl and arylsulfo group Group, an acyl group, an aryloxycarbonyl group, an alkoxycarbonyl group, a carbamoyl group, an imido group, a phosphino group, phosphinyl group, phosphinyloxy group, phosphinylamino group, a silyl group.

  Among the dyes represented by the general formula (Y-I), dyes represented by the following general formulas (Y-II), (Y-III), and (Y-IV) are more preferable.

In the general formula (Y-II), R ¹ and R ³ represent a hydrogen atom, a cyano group, an alkyl group, a cycloalkyl group, an aralkyl group, an alkoxy group, an alkylthio group, an arylthio group, an aryl group, or an ionic hydrophilic group. Represent. R ² represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aralkyl group, a carbamoyl group, an acyl group, an aryl group or a heterocyclic group. R ⁴ represents a heterocyclic group.

In the general formula (Y-III), R ⁵ represents a hydrogen atom, a cyano group, an alkyl group, a cycloalkyl group, an aralkyl group, an alkoxy group, an alkylthio group, an arylthio group, an aryl group, or an ionic hydrophilic group. Za represents -N =, - NH-, or C (R ¹¹⁾ = represents, Zb and Zc each independently, -N =, or C (R ¹¹⁾ = represents, R ¹¹ is a hydrogen atom or Represents a non-metallic substituent. R ⁶ represents a heterocyclic group.

In the general formula (Y-IV), R ⁷ and R ⁹ are each independently a hydrogen atom, cyano group, alkyl group, cycloalkyl group, aralkyl group, aryl group, alkylthio group, arylthio group, alkoxycarbonyl group, carbamoyl. Represents a group or an ionic hydrophilic group. R ⁸ is a hydrogen atom, halogen atom, alkyl group, alkoxy group, aryl group, aryloxy group, cyano group, acylamino group, sulfonylamino group, alkoxycarbonylamino group, ureido group, alkylthio group, arylthio group, alkoxycarbonyl group, It represents a carbamoyl group, sulfamoyl group, sulfonyl group, acyl group, alkylamino group, arylamino group, hydroxy group, or ionic hydrophilic group. R ¹⁰ represents a heterocyclic group.

The substituents represented by R ¹ , R ² , R ³ , R ⁵ , R ⁷ , R ⁸ and R ^{9 in the} general formulas (Y-II), (Y-III), and (Y-IV) are described in detail below. Describe.

The alkyl group represented by R ¹ , R ² , R ³ , R ⁵ , R ⁷ , R ⁸ and R ⁹ includes an alkyl group having a substituent and an unsubstituted alkyl group.
The alkyl group is preferably an alkyl group having 1 to 20 carbon atoms, and examples of the substituent include a hydroxyl group, an alkoxy group, a cyano group, a halogen atom, and an ionic hydrophilic group.
Preferable examples of the (substituted) alkyl group include methyl, ethyl, butyl, isopropyl, t-butyl, hydroxyethyl, methoxyethyl, cyanoethyl, trifluoromethyl, 3-sulfopropyl, and 4-sulfobutyl.

The cycloalkyl group represented by R ¹ , R ² , R ³ , R ⁵ , R ⁷ , R ⁸ and R ⁹ includes a cycloalkyl group having a substituent and an unsubstituted cycloalkyl group.
As the cycloalkyl group, a cycloalkyl group having 5 to 12 carbon atoms is preferable, and examples of the substituent include an ionic hydrophilic group.
Suitable examples of the cycloalkyl group include cyclohexyl.

The aralkyl group represented by R ¹ , R ² , R ³ , R ⁵ , R ⁷ , R ⁸ and R ⁹ includes an aralkyl group having a substituent and an unsubstituted aralkyl group.
The aralkyl group is preferably an aralkyl group having 7 to 20 carbon atoms, and examples of the substituent include an ionic hydrophilic group.
Suitable examples of the aralkyl group include benzyl and 2-phenethyl.

The aryl group represented by R ¹ , R ² , R ³ , R ⁵ , R ⁷ , R ⁸ and R ⁹ includes an aryl group having a substituent and an unsubstituted aryl group.
The aryl group is preferably an aryl group having 6 to 20 carbon atoms, and examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, an alkylamino group, and an ionic hydrophilic group.
Preferable examples of the (substituted) aryl group include phenyl, p-tolyl, p-methoxyphenyl, o-chlorophenyl, and m- (3-sulfopropylamino) phenyl.

The alkylthio group represented by R ¹ , R ² , R ³ , R ⁵ , R ⁷ , R ⁸ and R ⁹ includes an alkylthio group having a substituent and an unsubstituted alkylthio group.
The alkylthio group is preferably an alkylthio group having 1 to 20 carbon atoms, and examples of the substituent include ionic hydrophilic groups.
Preferable examples of the alkylthio group include a methylthio group and an ethylthio group.

The arylthio group represented by R ¹ , R ² , R ³ , R ⁵ , R ⁷ , R ⁸ and R ⁹ includes an arylthio group having a substituent and an unsubstituted arylthio group.
The arylthio group is preferably an arylthio group having 6 to 20 carbon atoms, and examples of the substituent include an alkyl group and an ionic hydrophilic group.
As said arylthio group, a phenylthio group and p-tolylthio are mentioned suitably, for example.

The heterocyclic group represented by R ² is preferably a 5-membered or 6-membered heterocyclic ring, which may be further condensed. As a hetero atom constituting the heterocyclic ring, a nitrogen atom, a sulfur atom and an oxygen atom are preferable. Further, it may be an aromatic heterocyclic ring or a non-aromatic heterocyclic ring. The heterocyclic ring may further have a substituent, and examples of the substituent include the same substituents as those of the aryl group described above. Preferred heterocycles include 6-membered nitrogen-containing aromatic heterocycles, among which triazine, pyrimidine and phthalazine are particularly preferred.

Preferred examples of the halogen atom represented by R ⁸ include a fluorine atom, a chlorine atom, and a bromine atom.
The alkoxy group represented by R ¹ , R ³ , R ⁵ , and R ⁸ includes an alkoxy group having a substituent and an unsubstituted alkoxy group.
As the alkoxy group, an alkoxy group having 1 to 20 carbon atoms is preferable, and examples of the substituent include a hydroxyl group and an ionic hydrophilic group.
Preferable examples of (substituted) alkoxy groups include methoxy, ethoxy, isopropoxy, methoxyethoxy, hydroxyethoxy, and 3-carboxypropoxy.

The aryloxy group represented by R ⁸ includes an aryloxy group having a substituent and an unsubstituted aryloxy group.
As the aryloxy group, an aryloxy group having 6 to 20 carbon atoms is preferable, and examples of the substituent include an alkoxy group and an ionic hydrophilic group.
Preferable examples of the (substituted) aryloxy group include phenoxy, p-methoxyphenoxy and o-methoxyphenoxy.
The acylamino group represented by R ⁸ includes an acylamino group having a substituent and an unsubstituted acylamino group.
The acylamino group is preferably an acylamino group having 2 to 20 carbon atoms, and examples of the substituent include an ionic hydrophilic group.
Preferable examples of the acylamino group include acetamido, propionamido, benzamido and 3,5-disulfobenzamido.

The sulfonylamino group represented by R ⁸ includes a sulfonylamino group having a substituent and an unsubstituted sulfonylamino group.
As the sulfonylamino group, a sulfonylamino group having 1 to 20 carbon atoms is preferable.
Preferable examples of the sulfonylamino group include methylsulfonylamino and ethylsulfonylamino.

The alkoxycarbonylamino group represented by R ⁸ includes an alkoxycarbonylamino group having a substituent and an unsubstituted alkoxycarbonylamino group.
The alkoxycarbonylamino group is preferably an alkoxycarbonylamino group having 2 to 20 carbon atoms, and examples of the substituent include an ionic hydrophilic group.
Preferred examples of the alkoxycarbonylamino group include ethoxycarbonylamino.

The ureido group represented by R ⁸ includes a ureido group having a substituent and an unsubstituted ureido group.
The ureido group is preferably a ureido group having 1 to 20 carbon atoms, and examples of the substituent include an alkyl group and an aryl group.
Preferable examples of the (substituted) ureido group include 3-methylureido, 3,3-dimethylureido and 3-phenylureido.

The alkoxycarbonyl group represented by R ⁷ , R ⁸ and R ⁹ includes an alkoxycarbonyl group having a substituent and an unsubstituted alkoxycarbonyl group.
As the alkoxycarbonyl group, an alkoxycarbonyl group having 2 to 20 carbon atoms is preferable, and examples of the substituent include an ionic hydrophilic group.
Preferable examples of the alkoxycarbonyl group include methoxycarbonyl and ethoxycarbonyl.

The carbamoyl group represented by R ² , R ⁷ , R ⁸ and R ⁹ includes a carbamoyl group having a substituent and an unsubstituted carbamoyl group. Examples of the substituent include an alkyl group.
Preferable examples of the (substituted) carbamoyl group include a methylcarbamoyl group and a dimethylcarbamoyl group.
The sulfamoyl group represented by R ⁸ includes a sulfamoyl group having a substituent and an unsubstituted sulfamoyl group. Examples of the substituent include an alkyl group.
Preferred examples of the (substituted) sulfamoyl group include a dimethylsulfamoyl group and a di- (2-hydroxyethyl) sulfamoyl group.

Preferable examples of the sulfonyl group represented by R ⁸ include methanesulfonyl and phenylsulfonyl.
The acyl group represented by R ² and R ⁸ includes an acyl group having a substituent and an unsubstituted acyl group. The acyl group is preferably an acyl group having 1 to 20 carbon atoms, and examples of the substituent include an ionic hydrophilic group.
Preferred examples of the acyl group include acetyl and benzoyl.

The amino group represented by R ⁸ includes an amino group having a substituent and an unsubstituted amino group. Examples of the substituent include an alkyl group, an aryl group, and a heterocyclic group.
Preferable examples of the (substituted) amino group include methylamino, diethylamino, anilino, and 2-chloroanilino.

The heterocyclic group represented by R ⁴ , R ⁶ , and R ¹⁰ is the same as the optionally substituted heterocyclic group represented by B in the general formula (YI), and is preferably a preferable example. Examples, particularly preferred examples are the same as described above.
Examples of the substituent include an ionic hydrophilic group, an alkyl group having 1 to 12 carbon atoms, an aryl group, an alkyl or arylthio group, a halogen atom, a cyano group, a sulfamoyl group, a sulfonamino group, a carbamoyl group, and an acylamino group. And the alkyl group and aryl group may further have a substituent.

In the general formula (Y-III), Za represents —N═, —NH—, or C (R ¹¹ ) ═. Zb and Zc each independently represent —N═ or C (R ¹¹ ) ═. Here, R ¹¹ represents a hydrogen atom or a nonmetallic substituent. As the nonmetallic substituent represented by R ¹¹ , a cyano group, a cycloalkyl group, an aralkyl group, an aryl group, an alkylthio group, an arylthio group, or an ionic hydrophilic group is preferable. Each of the substituents is synonymous with each substituent represented by R ¹ , and preferred examples are also the same. Examples of heterocyclic skeletons composed of two 5-membered rings included in the general formula (Y-III) are shown below.

Examples of the substituent in the case where each substituent described above may further have a substituent include a substituent that may be substituted on the heterocyclic rings A and B of the general formula (Y-I). Can be mentioned.
Specific examples (Y-101 to Y-155) of the dye represented by the general formula (Y-I) are shown in paragraph numbers [0139] to [0149] of JP-A No. 2003-073598. The dye used in is not limited to the following specific examples. These compounds can be synthesized with reference to JP-A-2-24191 and JP-A-2001-279145.

The magenta dye is preferably a compound having a structure represented by the general formulas (3) and (4) of JP-A No. 2002-114930. Specific examples thereof include paragraphs [0054] to [0073] of JP-A No. 2002-114930. The compound of this is mentioned.
Particularly preferred dyes are azo dyes represented by the general formulas (M-1) to (M-2) described in paragraph numbers [0084] to [0122] of JP-A No. 2002-121414, Examples thereof include compounds described in paragraph numbers [0123] to [0132] of JP-A No. 2002-121414. The oil-soluble dyes represented by the general formulas (3), (4), and (M-1) to (M-2) described in the publication are used not only for magenta but also for inks of any color such as black ink and red ink. May be.

Examples of the cyan dye include dyes represented by formulas (I) to (IV) of JP-A No. 2001-181547, and general formulas described in paragraph numbers [0063] to [0078] of JP-A No. 2002-121414. The dyes represented by IV-1) to (IV-4) are preferred, and specific examples include paragraph numbers [0052] to [0066] of JP-A No. 2001-181547 and paragraphs of JP-A No. 2002-121414. Compounds of numbers [0079] to [0081] are mentioned.
Particularly preferred dyes are phthalocyanine dyes represented by the general formulas (CI) and (C-II) described in paragraphs [0133] to [0196] of JP-A No. 2002-121414, and more generally A phthalocyanine dye represented by the formula (C-II) is preferred. Specific examples thereof include compounds of paragraph numbers [0198] to [0201] of JP-A No. 2002-121414. The oil-soluble dyes of the formulas (I) to (IV), (IV-1) to (IV-4), (C-I), and (C-II) are not only cyan but also black ink or green ink. It may be used for inks of any color.

The oil-soluble dye is preferably present in a dissolved state in the fine particles, and it is preferable that there is no crystal precipitation over time. That is, it is important that the compatibility with the dispersible polymer (particularly the hydrophobic portion thereof) is high.
The content of the oil-soluble dye can be arbitrarily selected for the stability of the dispersion, but is preferably 10 to 90% by mass, more preferably 15 to 85% by mass, and more preferably 20 to 50% by mass in the total dispersible polymer. Particularly preferred.
Further, the content of the oil-soluble dye in the ink composition is preferably 0.05 to 15% by mass, more preferably 0.1 to 10% by mass, and particularly preferably 0.2 to 6% by mass.

-Production of ink composition-
The ink composition of the present invention comprises an oil-soluble dye having an oxidation potential nobler than 1.0 V (vs SCE) and the dispersible polymer in an aqueous medium (a liquid containing at least water) and a nonionic surfactant. It is produced by dispersing in the form of fine particles using an agent. Specifically, for example, a method of preparing a latex of the dispersible polymer in advance and impregnating the latex with the oil-soluble dye, a co-emulsification dispersion method, or the like can be given.
Among these, the co-emulsification dispersion method is preferable. As the co-emulsification dispersion method, water is added to an organic solvent containing the dispersible polymer and the oil-soluble dye, and the organic solvent is added to water. A method of emulsifying and making fine particles is preferred.

  The latex means a dispersion of the dispersible polymer insoluble in the aqueous medium as fine particles in the aqueous medium. The dispersion state may be one in which the dispersible polymer is emulsified in an aqueous medium, emulsion polymerized, micelle-dispersed, or the dispersible polymer has a partially hydrophilic structure in the molecule. The molecular chain itself may be any molecularly dispersed one.

First, a method for preparing the polymer latex in advance and impregnating the polymer latex with the oil-soluble dye will be described.
A first example of this method includes a first step of preparing a polymer latex, a second step of preparing a colorant-containing liquid in which the oil-soluble dye is dispersed or dissolved in an organic solvent, and the colorant-containing liquid. And a third step of mixing the polymer latex and preparing a fine particle dispersion (ink composition).
A second example of this method is a first step of preparing a polymer latex, a colorant-containing liquid in which the oil-soluble dye is dispersed or dissolved in an organic solvent, and this colorant-containing liquid and at least water. A second step of preparing a colorant fine particle dispersion by mixing the liquid, and a third step of preparing a fine particle dispersion by mixing the polymer latex and the colorant fine particle dispersion.
As a third example of this method, there is a method described in JP-A No. 55-139471.

Next, the co-emulsification dispersion method will be described.
The first example of this method is a first step of preparing a polymer colorant mixture in which the oil-soluble dye and the dispersible polymer are dispersed or dissolved in an organic solvent, and the obtained polymer colorant mixture And a second step of preparing a fine particle dispersion by mixing with water containing an ionic surfactant.
The second example of this method is a first step of preparing a colorant-containing liquid in which the oil-soluble dye is dispersed or dissolved in an organic solvent, and a polymer solution in which the dispersible polymer is dispersed or dissolved in the organic solvent. A second step and a third step of preparing a fine particle dispersion by mixing the colorant-containing liquid, the polymer solution, and water containing a nonionic surfactant.
A third example of this method is to prepare a colorant-containing liquid in which the oil-soluble dye is dispersed or dissolved in an organic solvent, and mix this colorant-containing liquid with water containing a nonionic surfactant to color. The first step of preparing a fine agent particle dispersion, and preparing a polymer solution in which a dispersible polymer is dispersed or dissolved in an organic solvent, and mixing the polymer solution with water containing a nonionic surfactant to form a polymer fine particle A second step of preparing a dispersion, and a third step of preparing a fine particle dispersion by mixing the colorant fine particle dispersion and the polymer fine particle dispersion.
A fourth example of this method is to prepare a colorant-containing liquid in which the oil-soluble dye is dispersed or dissolved in an organic solvent, and mix this colorant-containing liquid with water containing a nonionic surfactant to color. A first step of preparing a colorant fine particle dispersion, a second step of preparing a polymer solution in which a dispersible polymer is dispersed or dissolved in an organic solvent, and mixing the colorant fine particle dispersion and the polymer solution. And a third step of preparing a fine particle dispersion.
A fifth example of this method is a step of directly preparing a fine particle dispersion by mixing the oil-soluble dye and the dispersible polymer with water containing a nonionic surfactant.

  The amount of the dispersible polymer used in the ink composition of the present invention is preferably 10 to 1000 parts by mass and more preferably 50 to 600 parts by mass with respect to 100 parts by mass of the oil-soluble dye. If the proportion of the polymer used is less than 10 parts by mass, fine and stable dispersion tends to be difficult, and if it exceeds 1000 parts by mass, the proportion of the oil-soluble dye in the fine particle dispersion is reduced and used as a water-based ink. When it does, there exists a tendency for the margin on a compounding design to be lost.

The content of the fine particles in the ink composition is preferably 1 to 45% by mass, and more preferably 2 to 30% by mass. The content can be appropriately adjusted by dilution, evaporation, ultrafiltration or the like.
The average particle diameter of the fine particles is preferably 1 to 500 nm, more preferably 3 to 300 nm, and particularly preferably 3 to 200 nm. The particle size distribution is not particularly limited, and may have a wide particle size distribution or a monodispersed particle size distribution. The particle size and the particle size distribution can be adjusted by means such as centrifugation and filtration.

In the present invention, a nonionic surfactant is used as a dispersant. Examples thereof include polyoxyethylene sorbitan fatty acid ester, sorbitan fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene derivative, oxyethylene / oxypropylene block copolymer, and the like. Here, the added mole number of oxyethylene is preferably 5 to 80, and more preferably 10 to 50.
The HLB of these surfactants is 8 or more, preferably 10 or more from the viewpoint of solubility in water.
The amount of the nonionic surfactant used is preferably 0.01 to 1.0 times by weight, and preferably 0.01 to 0.5 times by weight that of the oil-soluble dye.
In addition to the nonionic surfactant, an anionic surfactant may be used in an amount of 0.01 to 0.5 times the oil-soluble dye.

-Organic solvent-
The organic solvent used in producing the ink composition of the present invention is not particularly limited and can be appropriately selected based on the solubility of the oil-soluble dye or the dispersible polymer. For example, acetone, methyl ethyl ketone, Ketone solvents such as diethyl ketone, alcohol solvents such as methanol, ethanol, 2-propanol, 1-propanol, 1-butanol and tert-butanol, chlorine solvents such as chloroform and methylene chloride, and aromatics such as benzene and toluene Examples of the solvent include ester solvents such as ethyl acetate, butyl acetate, and isopropyl acetate, ether solvents such as diethyl ether, tetrahydrofuran, and dioxane, and glycol ether solvents such as ethylene glycol monomethyl ether and ethylene glycol dimethyl ether.
An organic solvent may be used independently and may use 2 or more types together. Depending on the solubility of the dye or polymer, a mixed solvent with water may be used.

The amount of the organic solvent used is not particularly limited as long as it does not impair the effects of the present invention, but is preferably 10 to 2000 parts by mass, and 100 to 1000 parts by mass with respect to 100 parts by mass of the dispersible polymer. Is more preferable.
When the amount of the organic solvent used is less than 10 parts by mass, fine and stable dispersion of fine particles tends to be difficult. When the amount exceeds 2000 parts by mass, solvent removal and concentration for removing the organic solvent are performed. The process becomes indispensable and complicated, and there is a tendency that there is no room for formulation design.

  When the vapor pressure of the organic solvent is higher than that of the water, the organic solvent is preferably removed from the viewpoint of the stability of the ink composition and safety and health. As a method for removing the organic solvent, various known methods can be used according to the type of the solvent. That is, an evaporation method, a vacuum evaporation method, an ultrafiltration method, and the like. This organic solvent removal step is preferably performed as soon as possible immediately after emulsification.

-Additives-
The ink composition of the present invention may contain an additive appropriately selected according to the purpose within a range not impairing the effects of the present invention.
Examples of the additive include a neutralizing agent, a hydrophobic high-boiling organic solvent, and a dispersion stabilizer.

When the dispersible polymer has an unneutralized dissociable group, the neutralizing agent can be suitably used in terms of adjusting the pH of the ink composition, adjusting the self-emulsifying property, imparting dispersion stability, and the like.
Examples of the neutralizing agent include organic bases and inorganic alkalis.

Examples of the organic base include triethanolamine, diethanolamine, N-methyldiethanolamine, dimethylethanolamine and the like.
Examples of the inorganic alkali include alkali metal hydroxides (for example, sodium hydroxide, lithium hydroxide, potassium hydroxide, etc.), carbonates (for example, sodium carbonate, sodium hydrogen carbonate, etc.), ammonia and the like.
From the viewpoint of improving the dispersion stability in the ink composition, the neutralizing agent is preferably added to have a pH of 4.5 to 10.0, and is preferably added to have a pH of 6.0 to 10.0. More preferred.

The hydrophobic high boiling point organic solvent is used for adjusting the viscosity, specific gravity, and printing performance of the ink composition. The hydrophobic high boiling point organic solvent is hydrophobic and preferably has a boiling point of 150 ° C. or higher, more preferably 170 ° C. or higher. Here, “hydrophobic” means that the solubility in distilled water at 25 ° C. is 3% or less. The dielectric constant of the hydrophobic high boiling point organic solvent is preferably 3 to 12, more preferably 4 to 10. Here, the dielectric constant means a relative dielectric constant with respect to a vacuum at 25 ° C. As the hydrophobic high boiling point organic solvent, compounds described in U.S. Pat. No. 2,322,027 and Japanese Patent Application No. 2000-78531 can be used. Specific examples include phosphoric acid triesters, phthalic acid diesters, alkylnaphthalenes, benzoic acid esters, and the like. Depending on the purpose, these can be either liquid or solid at room temperature.
The amount of the high-boiling solvent used is not particularly limited as long as it does not impair the effects of the present invention, but is preferably 0 to 1000 parts by weight, preferably 0 to 300 parts by weight with respect to 100 parts by weight of the dispersible polymer. Is more preferable.

-Use of ink composition-
The ink composition of the present invention can be used in various fields, but is suitable for a water-based ink for writing, a water-based printing ink, an information recording ink, and the like, and is particularly preferably used for the following ink-jet ink of the present invention. can do.

  When the ink composition is used as an ink for writing water-based ink, water-based printing ink, information recording ink, etc., the recording material of the ink is not particularly limited and includes known materials. Examples include plain paper, resin-coated paper, inkjet-only paper, film, electrophotographic co-paper, fabric, glass, metal, and ceramics.

(Inkjet ink, inkjet recording method, and recording material)
The ink-jet ink of the present invention contains the ink composition of the present invention, and further contains other additives appropriately selected as necessary. The other additives include drying inhibitors, penetration enhancers, antioxidants, antifungal agents, pH regulators, surface tension regulators, antifoaming agents, viscosity modifiers, dispersants, dispersion stabilizers, Known additives such as rusting agents and chelating agents can be mentioned, and those described in paragraph numbers (0217) to (0226) of JP-A No. 2001-279141 can be used.
As the ink for inkjet recording of the present invention, those described in paragraph No. (0247) of JP-A No. 2001-279141 can be used.

-Other additives-
Additives include water-soluble organic solvents, surface tension modifiers, viscosity modifiers, dispersants, dispersion stabilizers, antioxidants, antifungal agents, rust inhibitors, pH adjusters, antifoaming agents, chelating agents, UV absorbers An appropriate amount can be used by appropriately selecting an agent and the like. These additives are described in JP-A No. 2001-181549.
Water-soluble organic solvents are used for the purpose of drying inhibitors and penetration enhancers. The water-soluble organic solvent is preferably a water-soluble organic solvent having a vapor pressure lower than that of water. Specific examples include ethylene glycol, propylene glycol, diethylene glycol, polyethylene glycol, thiodiglycol, dithiodiglycol, 2-methyl-1,3-propanediol, 1,2,6-hexanetriol, glycerin, trimethylolpropane. , Substituted or unsubstituted fats typified by polyhydric alcohols typified by diethanolamine, amyl alcohol, furfuryl alcohol, diacetone alcohol, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, triethylene glycol monoethyl ether, etc. Group monohydric alcohols, 2-pyrrolidone, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, heterocyclic rings such as N-ethylmorpholine, sulfolane Dimethyl sulfoxide, sulfur-containing compounds such as 3-sulfolene and the like.
Of these, polyhydric alcohols and substituted or unsubstituted aliphatic monohydric alcohols are preferred, and polyhydric alcohols such as glycerin and diethylene glycol are more preferred. Moreover, said water-soluble organic solvent may be used independently and may be used together 2 or more types.
These water-soluble organic solvents are preferably contained in the ink in an amount of 5 to 60% by mass, more preferably 7 to 50% by mass, and particularly preferably 10 to 40% by mass.

Examples of the surface tension adjusting agent include nonionic, cationic and anionic surfactants. For example, anionic surfactants include fatty acid salts, alkyl sulfate esters, alkylaryl sulfonates (eg, alkylbenzene sulfonates, petroleum sulfonates, etc.), dialkyl sulfosuccinates, alkyl phosphate esters, naphthalene sulfones. Acid formalin condensate, polyoxyethylene alkyl sulfate ester salt and the like. Nonionic surfactants include acetylene diols (for example, 2,4,7,9-tetramethyl-5-decyne-4, 7-diol, etc.), polyoxyethylene alkyl ether (eg, polyoxyethylene decyl ether, ethylene oxide adduct of acetylenic diol), polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid Ester, polyoxyethylene alkylamine, glycerin fatty acid esters, and oxyethylene oxypropylene block copolymer.
An amine oxide type amphoteric surfactant such as N, N-dimethyl-N-alkylamine oxide is also preferred. Further, pages (37) to (38) of JP-A-59-157,636, Research Disclosure No. 308119 (1989) The listed surfactants can also be used.
Precipitation and separation from ink do not occur easily and foaming property is low, so that hydrophobic sites are double-stranded or anionic surfactants with hydrophobic sites branched or hydrophilic groups near the center of hydrophobic sites. Anionic surfactants having a hydrophobic structure, nonionic surfactants in which the hydrophobic part is double-stranded or the hydrophobic part is branched (for example, one-terminal ester of polyethylene oxide of 2-butyloctanoic acid, undecan-6-ol Polyethylene oxide adducts), nonionic surfactants having a hydrophilic group near the center of the hydrophobic site (for example, ethylene oxide adducts of acetylenic diols (SURFYNOL series (Air Products & Chemicals), etc.)) are preferred, Those having a molecular weight of 200 or more and 1000 or less are preferred, and a molecular weight of 300 Top 900 more preferably less ones, having a molecular weight of 400 or more 900 or less is particularly preferred.

The surface tension of the ink of the present invention is preferably 20 to 60 mN / m with or without using these. Furthermore, 25-45 mN / m is preferable. The dynamic surface tension is preferably 20 to 40 mN / m with or without these. Furthermore, 25-35 mN / m is preferable.
The viscosity of the ink of the present invention is preferably 30 mPa · s or less. Furthermore, it is more preferable to adjust to 20 mPa * s or less, and a viscosity modifier may be used in order to adjust a viscosity. Examples of the viscosity modifier include water-soluble polymers such as celluloses and polyvinyl alcohol.
Additives such as dispersants, dispersion stabilizers, antioxidants, antifungal agents, rust inhibitors, pH adjusters, antifoaming agents, chelating agents, and UV absorbers are described in JP-A No. 2001-181549. Known compounds can be used.

-Recording material-
Examples of the recording material used in the ink jet recording method using the ink of the present invention include plain paper, coated paper, and plastic film. Regarding the recording material, there are recording materials having a porous ink receiving layer containing inorganic fine particles described in paragraph numbers (0228) to (0246) of JP-A Nos. 2001-181549 and 2001-279141. preferable. The recording material is preferably recording paper.

Examples of the present invention will be described below, but the present invention is not limited to these examples. In the following, “parts” and “%” represent “parts by mass” and “% by mass” unless otherwise specified.
(Example 1)
-Production Example 1 (Preparation of fine particle dispersion (A-1))-
A mixed solution of 16 parts of ethyl acetate, 2.7 parts of dispersible polymer (PA-1) (solid content 50%), and 0.45 parts of the following oil-soluble dye (M-1) (oxidation potential 1.39 V) was prepared. On the other hand, a mixed solution of 18 parts of water and 0.4 parts of polyoxyethylene alkyl ether-Emulgen 320P (nonionic surfactant-Kao Corporation, HLB = 13.9) was prepared. The two mixed solutions were combined, mixed and emulsified with a homogenizer, and then concentrated under reduced pressure at 30 ° C. to prepare a fine particle dispersion having a solid content of 17%. The particle diameter of the fine particles in the fine particle dispersion was 95 nm in terms of volume average diameter. Hereinafter, this is abbreviated as a fine particle dispersion (A-1).

-Production Example 2 (Preparation of fine particle dispersion (A-2))-
A mixed solution of 16 parts of ethyl acetate, 2.7 parts of dispersible polymer (PA-1) (solid content 50%), and 0.45 part of oil-soluble dye (M-1) was prepared. On the other hand, 18 parts of water and 0.4 parts of polyoxyethylene alkyl ether-Emulgen 320P (nonionic surfactant-Kao Corporation), Emar 20C (anionic surfactant-Kao Corporation) 0.2 part A liquid mixture was prepared. The two mixed solutions were combined, mixed and emulsified with a homogenizer, and then concentrated under reduced pressure at 30 ° C. to prepare a fine particle dispersion having a solid content of 16.8%. The particle diameter of the fine particles in the fine particle dispersion was 62 nm in terms of volume average diameter. Hereinafter, this is abbreviated as a fine particle dispersion (A-2).

-Production Example 3 (Preparation of fine particle dispersion (A-3))-
A mixed solution of 16 parts of ethyl acetate, 2.7 parts of dispersible polymer (PA-1) (solid content 50%), and 0.45 part of oil-soluble dye (M-1) was prepared. On the other hand, a mixed solution of 18 parts of water and 0.4 part of polyoxyethylene alkyl ether-Emulgen 108 (nonionic surfactant-Kao Corporation, HLB = 12.1) was prepared. The two mixed solutions were combined, mixed and emulsified with a homogenizer, and then concentrated under reduced pressure at 30 ° C. to prepare a fine particle dispersion having a solid content of 17.3%. The particle diameter of the fine particles in the fine particle dispersion was 102 nm in terms of volume average diameter. Hereinafter, this is abbreviated as a fine particle dispersion (A-3).

-Production Example 4 (Preparation of fine particle dispersion (A-4))-
A mixed solution of 16 parts of ethyl acetate, 2.7 parts of dispersible polymer (PA-13) (solid content 50%), and 0.45 part of oil-soluble dye (M-1) was prepared. On the other hand, a mixed solution of 18 parts of water and 0.4 part of polyoxyethylene alkyl ether-Emulgen 108 (nonionic surfactant-Kao Co., Ltd.) was prepared. The two mixed solutions were combined, mixed and emulsified with a homogenizer, and then concentrated under reduced pressure at 30 ° C. to prepare a fine particle dispersion having a solid content of 17.8%. The particle diameter of the fine particles in the fine particle dispersion was 95 nm in terms of volume average diameter. Hereinafter, this is abbreviated as a fine particle dispersion (A-4).

-Production Example 5 (Preparation of fine particle dispersion (A-5))-
A mixed solution of 16 parts of ethyl acetate, 2.7 parts of dispersible polymer (PA-13) (solid content 50%), and 0.45 part of oil-soluble dye (M-1) was prepared. On the other hand, 18 parts of water and 0.4 parts of polyoxyethylene alkyl ether-Emulgen 108 (nonionic surfactant-Kao Co., Ltd.), Emar 20C (anionic surfactant-Kao Co., Ltd.) 0.2 part A liquid mixture was prepared. The two mixed solutions were combined, mixed and emulsified with a homogenizer, and then concentrated under reduced pressure at 30 ° C. to prepare a fine particle dispersion having a solid content of 16.5%. The particle diameter of the fine particles in the fine particle dispersion was 112 nm in terms of volume average diameter. Hereinafter, this is abbreviated as a fine particle dispersion (A-5).

-Comparative Production Example 1 (Preparation of fine particle dispersion (B-1))-
A mixed solution of 16 parts of ethyl acetate, 2.7 parts of dispersible polymer (PA-1) (solid content 50%), and 0.45 part of oil-soluble dye (M-1) was prepared. On the other hand, a mixed solution of 18 parts of water and 0.4 part of Emar 20C (anionic surfactant-Kao Co., Ltd.) was prepared. The two mixed solutions were combined, mixed and emulsified with a homogenizer, and then concentrated at 30 ° C. under reduced pressure to prepare a fine particle dispersion having a solid content of 17.4%. The particle diameter of the fine particles in the fine particle dispersion was 72 nm in terms of volume average diameter. Hereinafter, this is abbreviated as a fine particle dispersion (B-1).

[Example 2]
<Preparation of ink 01>
The following materials were mixed and filtered through a 0.45 μm filter to prepare an aqueous inkjet recording ink 01.
・ Particulate dispersion (A-1) 50 parts ・ Diethylene glycol 5 parts ・ Glycerin 18 parts ・ Diethanolamine 1 part ・ Orphine E1010 0.9 part ・ Water Total amount of 100 parts

<Preparation of ink 02>
The following materials were mixed and filtered through a 0.45 μm filter to prepare an aqueous inkjet recording ink 02.
・ Particulate dispersion (A-1) 50 parts ・ Diethylene glycol 5 parts ・ Glycerin 10 parts ・ 1,2-hexanediol 8 parts ・ Diethanolamine 1 part ・ Orphine E1010 0.9 part ・ Water 100 parts in total

<Preparation of inks 03 to 06>
The ink 01 was prepared except that the fine particle dispersion (A-1) was replaced with the fine particle dispersion (A-2 to 5) prepared in Production Examples 2 to 5 of Example 1 in the preparation of the ink 01. Water-based ink jet recording inks 03 to 06 were prepared in the same manner as described above.

<Preparation of Comparative Example Ink-1>
The following materials were mixed and filtered through a 0.45 μm filter to prepare an aqueous ink jet comparative example ink-1.
・ Particulate dispersion (B-1) 50 parts ・ Diethylene glycol 5 parts ・ Glycerin 18 parts ・ Diethanolamine 1 part ・ Orphine E1010 0.9 g
・ Amount of water to be 100 parts

<Preparation of Comparative Example Ink-2>
The following materials were mixed and filtered through a 0.45 μm filter to prepare an aqueous ink jet comparative example ink-1.
・ Water-soluble dye DD-1 4 parts ・ Diethylene glycol 8 parts ・ Triethylene glycol monobutyl ether 7 parts ・ Glycerin 10 parts ・ Diethanolamine 1 part ・ Orphine E1010 0.2 g
・ Amount of water to be 100 parts

-Image recording and evaluation-
The prepared inks 01 to 05 and comparative example inks 1 and 2 are filled into a cartridge of an ink jet printer MC-2000 (manufactured by EPSON), and using the same machine, plain paper for PPC and ink jet paper photo glossy paper “ Images were recorded on “Painting” (manufactured by Fuji Photo Film Co., Ltd.) and evaluated as follows. The evaluation results are shown in Table 2.

<Print performance evaluation>
The cartridge was set in the printer, and after confirming the ejection of ink from all nozzles, an image was output on 10 sheets of A4 paper, and printing disturbance was evaluated according to the following criteria.
A: There was no disorder in printing from the start to the end of printing.
B: Disturbance of printing occasionally occurred from the start to the end of printing.
C: The printing was disturbed from the start to the end of printing.

<Paper dependency evaluation>
The color tone of the image formed on the photo glossy paper and the image formed on the PPC plain paper is compared. A when there is almost no difference between the two images, B when the difference between the two images is small, and between the two images. A case where the difference between the two was large was defined as C, and was evaluated in three stages.

<Water resistance evaluation>
The photo glossy paper on which the image was formed was dried at room temperature for 1 hour, then dipped in water for 30 seconds, naturally dried at room temperature, and observed for bleeding. Evaluation was made in three stages, with A indicating no bleeding, B indicating slight bleeding, and C indicating large bleeding.

<Evaluation of ink permeability>
Time until ink penetrates into the paper by landing 15 μL of the ink liquid on inkjet paper photo glossy paper “Image” (Fuji Photo Film Co., Ltd.) and observing the ink droplet with a high-speed camera. Was measured. The permeation time was evaluated in three stages with A being 1 s or less, B being 1 to less than 30 s, and C being 30 s or more.

<Abrasion resistance evaluation>
The photo glossy paper on which the image was formed was rubbed 10 times with an eraser for the image that had passed 30 minutes after image printing, and the change was observed. Evaluation was made in three stages, with A indicating no decrease in concentration, B indicating a slight decrease in concentration, and C indicating a large decrease in concentration.

<Light resistance evaluation>
The photo glossy paper on which the image is formed is irradiated with xenon light (85000 lx) for 4 days using a weather meter (Atlas C.I65), and the image density before and after the xenon irradiation is measured using a reflection densitometer (X-Rite310TR). And measured as a dye residual ratio. The reflection density was measured at three points of 1, 1.5 and 2.0. Evaluation was made in three stages, with A as the case where the dye residual ratio was 80% or higher at any concentration, and B as 1 or 2 points of less than 80%, and C as less than 80% at all concentrations.

<Ozone resistance>
The ozone resistance was evaluated by measuring the concentration of the sample before and after storing the sample for 3 days under an ozone concentration of 1.0 ppm with X-rite 310 to determine the residual ratio of the dye.
When the residual ratio of the dye was 90% or more, the evaluation was made in five stages: A, 89-80% as B, 79-70% as C, 69-50% as D, and less than 49% as E.

  As is apparent from the results in Table 2, the inks for ink jet recording of 01, 03 to 06 and 1,2-hexanediol were used as the ink solvent, using nonionic surfactants alone and in combination with anionic surfactants. The 02 ink for ink jet recording was excellent in printing performance, was not dependent on paper, and was excellent in water resistance, penetrability, high scratch resistance, light resistance, dark heat fastness, and ozone resistance. On the other hand, the inkjet recording ink of Comparative Example-1 using only an anionic surfactant is inferior in permeability, and the inkjet recording ink of Comparative Example-2 that does not use the fine particles of the present invention is inferior in some performances. I understand.

According to the present invention, when printing is performed using a nozzle or the like, there is no clogging at the nozzle tip, there is no paper dependency, water resistance when printing on arbitrarily selected paper, An ink for ink jet recording and an ink jet recording method excellent in scratch resistance and light resistance can be provided.

Claims (7)

  An ink composition, wherein fine particles containing an oil-soluble dye having a noble oxidation potential higher than 1.0 V (vs SCE) and a dispersible polymer are dispersed in an aqueous medium by a nonionic surfactant.   The ink composition according to claim 1, wherein an anionic surfactant is further used in addition to the nonionic surfactant.   The ink composition according to claim 1 or 2, wherein the nonionic surfactant has an HLB of 8 or more.   The ink composition according to claim 1, 2, or 3, wherein the nonionic surfactant is used in an amount of 0.01 to 1.0 times the weight of the oil-soluble dye.   Furthermore, the ink composition of any one of Claims 1-4 containing 1 type, or 2 or more types chosen from alcohol, polyhydric alcohol, and water-soluble glycol ethers.   An ink jet recording method comprising a step of recording an image on a recording material using the ink composition according to claim 1.   The recording method according to claim 6, wherein the recording material is a recording material having a porous ink receiving layer containing inorganic fine particles.