JP2005272491A - Dispersion comprising fine particle, ink and method for inkjet recording using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dispersion comprising fine particles having a small particle diameter of dispersed particles and excellent dispersion stability and preservation stability of the dispersion, to provide an ink having excellent printing characteristics and image fastness after recording (water, light, fretting and ozone resistances) by using the dispersion containing the fine particles and to further provide a method for inkjet recording with which recording with the excellent printing characteristics and image fastness after recording (water, light, fretting and ozone resistances) can be carried out by using the ink. <P>SOLUTION: The dispersion comprises the fine particles and an oil-soluble compound in latex fine particles composed of a polymer having a hydrophobic polymer moiety alone or the hydrophobic polymer moiety and a hydrophilic polymer moiety. The ink comprises the dispersion. The method for inkjet recording is carried out by using the ink. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a dispersion containing water-based fine particles containing an oil-soluble compound, an ink containing a dispersion containing the fine particles, and an ink jet recording method using the ink.

  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, the light resistance is poor, and the recording material provided with an ink receiving layer containing porous inorganic fine particles on the surface (hereinafter referred to as “photo quality paper”) In other cases, the image storability is extremely poor 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, for example, Patent Document 1). However, there are problems such as lack of storage stability of the dispersion of pigments and disperse dyes in the water-based ink, and clogging at the ink discharge port. Furthermore, in photographic image quality paper, inks using the pigments and dyes have poor penetration, 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 (see, for example, Patent Documents 2 to 4), but the color tone is insufficient, color reproducibility is not sufficient, and particularly due to an oxidizing gas or the like. The image durability is not sufficient, and when printed on photographic quality paper, the scratch resistance is not sufficient. By introducing a salt-forming group and a polyalkylene oxide group into the polymer, an ink having excellent colorability and scratch resistance has been proposed (for example, see Patent Document 5), but the scratch resistance by fingers is good. A high level of scratch resistance, such as eraser scrubbing, is insufficient. In addition, 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 6), but when a high level of image durability is required. It is insufficient.

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, a fine particle dispersion that has excellent scratch resistance and enables high-quality recording at a high concentration has not yet been provided.
JP 56-157468 A (all pages) JP 58-45272 A (all pages) JP-A-62-241901 (all pages) JP 55-139471 A (all pages) JP 2001-123097 (all pages) JP 2001-262018 A (all pages)

An object of the present invention is to solve the conventional problems and achieve the following objects. That is,
The present invention provides a dispersion containing fine particles having a small particle size of the dispersed particles and excellent dispersion stability and storage stability of the dispersion, and printing characteristics by using the dispersion containing the fine particles, An object of the present invention is to provide an ink having excellent image fastness (water resistance, light resistance, scratch resistance, ozone resistance) after recording.
Furthermore, the present invention provides an ink jet recording method capable of recording with excellent printing characteristics and image fastness after recording (water resistance, light resistance, scratch resistance, ozone resistance) by using the ink. With the goal.

<1> A dispersion containing fine particles characterized by containing an oil-soluble compound in latex fine particles comprising a hydrophobic polymer portion alone or a polymer having a hydrophobic polymer portion and a hydrophilic polymer portion.
<2> The dispersion containing fine particles according to <1>, wherein the hydrophilic polymer portion is anionic, nonionic, or a mixed type thereof.
<3> The dispersion containing fine particles according to <1> or <2>, wherein the oil-soluble compound is an oil-soluble dye.
<4> The dispersion containing fine particles according to <3>, wherein the oil-soluble dye has an oxidation potential nobler than 1.0 V (vs SCE).
<5> An ink comprising a dispersion containing the fine particles according to any one of the above items <1> to <4>.
<6> An ink jet recording method comprising a step of recording an image on a recording material using the ink according to the above <5>.
<7> The inkjet recording method according to <6>, wherein the recording material is a recording material provided with a porous ink receiving layer containing inorganic fine particles.

The fine particle dispersion of the present invention has handleability, low odor, and safety, and is suitable for aqueous ink for writing, aqueous printing ink, and information recording ink (thermal, piezoelectric, electric field or acoustic ink jet method). The particle size is small, and the dispersion is excellent in dispersion stability and storage stability.
The ink of the present invention has handleability, low odor, and safety, and is suitable for water-based ink for writing, water-based printing ink, information recording ink (thermal, piezoelectric, electric field, or acoustic ink jet method) and dispersed. Small particle size, excellent dispersion stability and storage stability of the dispersion, less clogging at the nozzle tip, no paper dependence, and printing characteristics such as ink permeability to photographic quality paper Also excellent in image fastness after recording (water resistance, light resistance, scratch resistance, ozone resistance).
Furthermore, the ink jet recording method of the present invention is a method that is excellent in the printing characteristics by using the ink, and excellent in the image fastness after recording.

  Hereinafter, a dispersion containing fine particles of the present invention (hereinafter also referred to as “fine particle dispersion”), an ink, an inkjet recording method, and the like will be described.

(Dispersion containing fine particles)
The fine particle dispersion of the present invention is a dispersion of fine particles containing an oil-soluble compound in latex fine particles composed of a polymer having a hydrophobic polymer portion alone or a polymer having a hydrophobic polymer portion and a hydrophilic polymer portion.
The fine particle dispersion is obtained by dispersing the fine particles in an aqueous medium, and if necessary, a hydrophobic high boiling point organic solvent and other colorants are dispersed in the form of fine particles. .
In addition, the “aqueous medium” in the present invention means a mixture of water or a mixture of water and a small amount of a water-miscible organic solvent with additives and the like added as necessary.

-Latex fine particles-
The latex fine particles will be described in detail.
The latex fine particles are produced by a so-called emulsion polymerization method and can be produced using a known polymerization technique.
As described above, the latex particulates need to be a polymer having a hydrophobic polymer site alone or a hydrophobic polymer site and a hydrophilic polymer site.

  The arrangement of the hydrophobic polymer site and the hydrophilic polymer site in the polymer is arbitrary, but the hydrophilic polymer site 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 site, A block copolymer having a hydrophilic polymer moiety at the end is preferred.

  The polymer may be any conventionally known polymerization type such as a vinyl polymer or a condensation polymer (polyurethane, polyester, polyamide, polyurea, polycarbonate), but a vinyl polymer is preferred because the structure of the polymer can be easily controlled.

The hydrophobic polymer portion is a portion of the polymer that has the property of being insoluble in water and not being dispersed when a polymer comprising monomers constituting the hydrophobic polymer portion is formed. The glass transition temperature (Tg) of the polymer is preferably 0 ° C. or lower, Tg is more preferably −15 ° C. or lower, further preferably −30 ° C. or lower, and particularly preferably −40 ° C. or lower.
When the Tg exceeds 0 ° C., the scratch resistance may not be sufficient when recording is performed using the photographic image quality paper which is difficult to scratch.

  Examples of monomers constituting the hydrophobic polymer moiety include acrylic esters and methacrylic esters (the ester group is a substituted or unsubstituted aliphatic group, a substituted or unsubstituted aromatic group, such as a 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 , Phenyl group, 2,4,5-tetramethyl phenyl, 4-chlorophenyl group);

Acrylamides, methacrylamides, specifically, N-monosubstituted acrylamides, N-disubstituted acrylamides, N-monosubstituted methacrylamides, N-disubstituted methacrylamides (substituents are substituted or unsubstituted aliphatic groups, Substituted or unsubstituted aromatic group, for example, methyl group, ethyl group, n-propyl group, isopropyl group, 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. );

Olefins, specifically dicyclopentadiene, ethylene, propylene, 1-butene, 1-pentene, vinyl chloride, vinylidene chloride, isoprene, chloroprene, butadiene, 2,3-dimethylbutadiene, etc .; 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 .;

Vinyl ethers, specifically methyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, methoxyethyl vinyl ether, etc .;
Other monomers include butyl crotonate, hexyl crotonate, dimethyl itaconate, dibutyl itaconate, diethyl maleate, dimethyl maleate, dibutyl maleate, diethyl fumarate, dimethyl fumarate, dibutyl 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-acryloyl Examples thereof include oxyethyl phosphate and dioctyl-2-methacryloyloxyethyl phosphate.

  Among the hydrophobic polymer sites, an ester group is an unsubstituted aliphatic group, an alkyl-substituted aromatic group, an acrylic acid ester or a methacrylic acid ester that is an aromatic group, a substituent is an unsubstituted aliphatic group, an alkyl group N-monosubstituted acrylamide, N-disubstituted acrylamide, N-monosubstituted methacrylamide, and N-disubstituted methacrylamide which are substituted phenyl groups or phenyl groups are preferable, and ester groups are aliphatic groups having 1 to 20 carbon atoms, More preferred are alkyl-substituted aromatic groups having 7 to 30 carbon atoms, and acrylic acid esters and methacrylic acid esters which are aromatic groups. The ester group is an aliphatic group having 1 to 20 carbon atoms and an alkyl group having 7 to 30 carbon atoms. A substituted phenyl group and an acrylic acid ester or a methacrylic acid ester which is a phenyl group are more preferable, and the ester group has a carbon number. Acrylic acid esters and methacrylic acid esters having an aliphatic group of 1 to 20 are more preferable, such as hexyl methacrylate, 2-ethylhexyl methacrylate, butyl acrylate, isobutyl acrylate, s-butyl acrylate, ethyl acrylate, propyl acrylate, hexyl acrylate, 2 -Ethylhexyl acrylate is more preferred, and hexyl methacrylate, butyl acrylate, isobutyl acrylate, s-butyl acrylate, propyl acrylate, and hexyl acrylate are particularly preferred.

  As the hydrophobic polymer portion, one kind of constituent raw material may be used, or two kinds may be used for various purposes (for example, adjustment of solubility, compatibility with oil-soluble compounds, stability of dispersion, etc.). Although the above may be used, it is preferable that the Tg of the polymer corresponding to the hydrophobic polymer portion obtained from the constituent raw materials is 0 ° C. or lower.

The said hydrophilic polymer site | part is a polymer site | part which has a property melt | dissolved in water, when the polymer which consists of the monomer which comprises a hydrophilic polymer site | part is formed. The hydrophilic polymer portion may be cationic, anionic, nonionic, or a mixed type thereof, but is preferably anionic, nonionic, or a mixed type thereof.
As a cationic polymer site, a polymer having a cationic dissociation group such as a tertiary amino group or pyridine group, and as an anionic polymer site, a polymer containing an anionic dissociation group such as carboxylic acid or sulfonic acid. Examples of the nonionic polymer moiety include a polymer containing a nonionic dispersible group such as an ethyleneoxy group, an alcohol group, and a pyrrolidone group.

Examples of monomers or polymer structural units constituting hydrophilic polymers include monomers having an acid such as a carboxyl group or a sulfo group (acrylic acid, methacrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, 2-carboxyethyl acrylate, etc. ), Acrylic acid esters and methacrylic acid esters having a hydrophilic substituent at the ester site (hydrophilic substituents such as hydroxy group, carboxyl group, amino group, etc.), acrylamide, methacrylamide, N-mono substitution Examples include acrylamide, N-disubstituted acrylamide, N-monosubstituted methacrylamide, N-disubstituted methacrylamide, vinyl pyrrolidone, polyethylene oxide moiety, polyvinyl alcohol moiety, and polyhydric alcohol moieties such as sugar and glycerin.
Among them, acrylic acid, methacrylic acid, 2-carboxyethyl acrylate, acrylic acid esters having a hydroxy group and methacrylic acid esters (examples of ester groups having a hydroxy group include 2-hydroxyethyl group, 2,3-dihydroxy Propyl group, etc.), acrylamide, N-monosubstituted acrylamide, N-disubstituted acrylamide, N-monosubstituted methacrylamide, N-disubstituted methacrylamide, polyethylene oxide having 1 to 4 total carbon atoms of substituents on nitrogen Sites, polyvinyl alcohol sites, polyhydric alcohol sites such as sugar and glycerin are preferred, and acrylic acid, methacrylic acid, 2-carboxyethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2,3-dihydroxypropyl Pyracrylate 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 moiety, and polyvinyl alcohol moiety are included. More preferred are 2,3-dihydroxypropyl acrylate, 2,3-dihydroxypropyl methacrylate and polyethylene oxide.

  As long as the hydrophilic polymer portion functions as a hydrophilic portion, one kind of constituent raw material may be used, and for various purposes (for the stability of the dispersion in each aqueous medium, for the production of the dispersion). Two or more types may be used for adjusting the solubility of the polymer.

  The content of the hydrophobic polymer portion and the hydrophilic polymer portion in the latex fine particles is arbitrary depending on the respective properties (for example, difference in water solubility of the hydrophilic polymer portion, 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 preferably 60 to 85% by weight. The hydrophilic polymer part is more preferably 15 to 40% by mass, the hydrophobic polymer part is preferably 60 to 80% by mass, and the hydrophilic polymer part is particularly preferably 20 to 40% by mass.

  When the hydrophilic polymer portion has the anionic dissociable group, the content of the dissociable group is preferably 0.1 to 3.0 mmol / g, 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, and when the content is large, the water solubility is high and the polymer tends to be unsuitable for dispersing the dye.

  In addition, as the dissociating group, the anionic dissociating group may be an alkali metal (for example, Na, K, etc.) or a salt of ammonium ion, and the cationic dissociating group is further It may be a salt of an organic acid (for example, acetic acid, propionic acid, methanesulfonic acid) or an inorganic acid (hydrochloric acid, sulfuric acid, etc.).

  As a weight average molecular weight (Mw) of the said polymer, it is 500-200000 normally, and 1000-50000 are preferable. When the molecular weight is less than 500, it tends to be difficult to obtain a stable fine particle dispersion. When the molecular weight is more than 200000, the solubility in an organic solvent is deteriorated or the viscosity of the organic solvent solution is increased and dispersed. It tends to be difficult.

The polymers constituting the latex fine particles may be used alone or in combination of two or more.
Moreover, you may add other polymers other than the said polymer in the range which does not inhibit the effect of this invention.

  Specific examples of the polymer constituting the latex fine particles are listed below. The ratio in parentheses means the mass ratio. The present invention is not limited to these specific examples.

PA-1) Butyl acrylate homopolymer PA-2) Copolymer of butyl acrylate / ethyl acrylate = 1/1 PA-3) Ternary copolymer of butyl acrylate / ethyl acrylate / styrene = 5/3/2 PA-4) Methacrylate copolymer of butyl acrylate / styrene / polyethylene glycol monomethyl ether (ethyleneoxy chain repeat number about 23) (5/4/1)
PA-5) Methacrylate ester copolymer of butyl acrylate / polyethylene glycol monomethyl ether (ethyleneoxy chain repeat number about 23) (60:40)
PA-6) Methacrylate ester copolymer of butyl methacrylate / polyethylene glycol monomethyl ether (ethyleneoxy chain repeat number about 23) (60:40)
PA-7) Hexyl methacrylate / 2,3-dihydroxypropyl acrylate copolymer (85:15)
PA-8) Methacrylic acid ester copolymer (70:30) of isobutyl acrylate / polyethylene glycol monomethyl ether (ethyleneoxy chain repeat number about 45)
PA-9) s-butyl acrylate / 2,3-dihydroxypropyl methacrylate copolymer (82:18)
PA-10) Methacrylic acid ester copolymer (70:10:20) of hexyl methacrylate / 2-carboxyethyl acrylate / polyethylene glycol monomethyl ether (ethyleneoxy chain repeat number about 23)
PA-11) Macromonomer copolymer having butyl acrylate / poly (2,3-dihydroxypropyl acrylate) moiety (80:20)
PA-12) Methacrylate copolymer of butyl acrylate / isobutyl acrylate / polyethylene glycol monomethyl ether (ethyleneoxy chain repeat number about 9) (50:20:30)
PA-13) Macromonomer copolymer containing butyl acrylate / acrylic acid as a structural unit (80:20)
PA-14) Methacrylic acid ester copolymer of butyl acrylate / polyethylene glycol monomethyl ether (ethyleneoxy chain repeat number about 23) / methacrylic acid ester copolymer of polyethylene glycol monomethyl ether (ethyleneoxy chain repeat number about 9) (70 : 20: 10)
PA-15) Methacrylate ester copolymer (70:10:20) of butyl acrylate / 1H, 1H, 2H, 2H-perfluorohexyl acrylate / polyethylene glycol monomethyl ether (ethyleneoxy chain repeat number about 23)
PA-16) A methacrylic acid ester copolymer (75: 5: 20) of a macromonomer / polyethylene glycol monomethyl ether having a butyl acrylate / poly (dimethylsiloxane) moiety (ethyleneoxy chain repeating number of about 23).

-Oil-soluble compounds-
The oil-soluble compound in the present invention is not particularly limited as long as it is a water-insoluble compound, and can be appropriately selected from known compounds according to the purpose within a range not impairing the effects of the present invention. For example, an ultraviolet absorber, an antioxidant, a light fading inhibitor, a liquid crystal compound, a fluorescent compound, an oil-soluble dye, an electron-donating colorless dye, an organic EL material, and respective polymers and oil-soluble polymers can be used.
The oil-soluble compound in the present invention means a compound that is substantially insoluble in water. More specifically, the solubility in water at 25 ° C. (the mass of the compound that can be dissolved in 100 g of water) is 1 g or less, Preferably it is 0.5 g or less, more preferably 0.1 g or less.
Among these, examples of the oil-soluble compound in the present invention include water-insoluble pigments and oil-soluble dyes, and oil-soluble dyes are particularly preferable.

The oil-soluble compound 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 compound having a low melting point, crystal precipitation of a dye in the ink described later is suppressed, and the storage stability of the ink is improved.
These oil-soluble compounds 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.

  As the oil-soluble compound, a conventionally known compound (dye) can be used. Specific examples include the dyes described in paragraphs [0023] to [0053] of JP-A No. 2002-114930.

The oil-soluble compound preferably has a noble (high) oxidation potential in order to improve fading, in particular, resistance to oxidizing substances such as ozone and curing properties. In particular, it is desirable that the oxidation potential of the oil-soluble dye is more noble than 1.0 V (vs SCE). The oxidation potential is preferably noble, the oxidation potential is more noble than 1.1 V (vs SCE), more preferably nobler than 1.2 V (vs SCE), 1.3 V ( It is particularly preferred that it is noble than (vs SCE).
The oxidation potential is described in paragraphs [0049] to [0051] of JP-A-2002-309118.

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

  In the above general formula (Y-I), A and B each independently represents an optionally substituted heterocyclic group. 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, or an aryl group. 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, or an aryl group. Za represents -N =, - NH-, or C (R ¹¹⁾ = represents, Zb and Zc each independently, -N =, or C (R ¹¹⁾ = represents the R ¹¹ is a hydrogen atom Or represents a non-metallic substituent. R ⁶ represents a heterocyclic group.

In 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, or Represents a carbamoyl 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, a sulfamoyl group, a sulfonyl group, an acyl group, an alkylamino group, an arylamino group, or a hydroxy 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, and a halogen atom.
Preferable examples of the 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.
The cycloalkyl group is preferably a cycloalkyl group having 5 to 12 carbon atoms, and examples of the substituent include a halogen atom.
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 a hydroxyl group, an alkoxy group, a cyano group, and a halogen atom.
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 , 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, and an alkylamino group.
Preferable examples of the 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 a hydroxyl group, an alkoxy group, a cyano group, and a halogen atom.
Preferable examples of the alkylthio group include methylthio and ethylthio.

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.
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 be further substituted, and examples of the substituent preferably include the same substituents as those described later for the aryl group. 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.
Suitable examples of the alkoxy group 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.
The aryloxy group is preferably an aryloxy group having 6 to 20 carbon atoms, and examples of the substituent include an alkoxy group.
Preferable examples of the 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 a hydroxyl group, an alkoxy group, a cyano group, and a halogen atom.
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.
The sulfonylamino group is preferably a sulfonylamino group having 1 to 20 carbon atoms.
Suitable 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 a hydroxyl group, an alkoxy group, a cyano group, and a halogen atom.
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.
Suitable examples of the 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.
The alkoxycarbonyl group is preferably an alkoxycarbonyl group having 2 to 20 carbon atoms, and examples of the substituent include a halogen atom.
Suitable 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.
Preferred examples of the 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 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 a hydroxyl group, an alkoxy group, a cyano group, and a halogen atom.
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 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 alkyl groups having 1 to 12 carbon atoms, aryl groups, alkyl or arylthio groups, halogen atoms, cyano groups, sulfamoyl groups, sulfonamino groups, carbamoyl groups, and acylamino groups. The group, aryl group and the like 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 ) ═. R ¹¹ represents a hydrogen atom or a nonmetallic substituent. As the nonmetal substituent represented by R ¹¹ , a cyano group, a cycloalkyl group, an aralkyl group, an aryl group, an alkylthio group, or an arylthio 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 the skeleton of a heterocyclic ring composed of two 5-membered rings contained 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-160) of the dye represented by the general formula (Y-I) are shown below, but the present invention 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.

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

Preferred structures of the cyan dye in the oil-soluble compound include dyes represented by formulas (I) to (IV) of JP-A No. 2001-181547, paragraph numbers [0063] to [0078] of JP-A No. 2002-121414. The dyes represented by the general formulas (IV-1) to (IV-4) described in the paragraphs [0052] to [0066] of JP2001-181547, and JP2002 The compounds of paragraph Nos. [0079] to [0081] of No. 12214 are mentioned.
Particularly preferred structures are phthalocyanine dyes represented by general formulas (CI) and (C-II) described in paragraphs [0133] to [0196] of JP-A No. 2002-121414, A phthalocyanine dye represented by formula (C-II) is preferred. Specific examples include compounds of paragraph numbers [0198] to [0201] of JP-A No. 2002-121414. The formulas (I) to (IV), (IV-1) to (IV-4), (C-
The oil-soluble compounds (I) and (C-II) may be used not only for cyan ink but also for ink of any color such as black ink and green ink.

The oil-soluble compound is preferably present in a state of being dissolved in the fine particles, and it is also preferable that there is no crystal precipitation over time. That is, it is preferable that the compatibility with the polymer (particularly, the hydrophobic portion thereof) is high.
The content of the oil-soluble compound 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 particularly preferably 20 to 50% by mass in the fine particles. preferable.
The content of the oil-soluble compound in the ink 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 fine particle dispersion-
The fine particle dispersion of the present invention is prepared by preparing a latex of the polymer in advance and impregnating the latex with the oil-soluble compound, a method of emulsion polymerization in the presence of the monomer and the oil-soluble compound in the preparation of the latex, or a co-emulsification dispersion. Law.
As the co-emulsification dispersion method, the organic solvent is emulsified by either adding water to the organic solvent containing the polymer and the oil-soluble compound or adding the organic solvent to water. A preferred method is to make them fine particles. Among these, a method of preparing a latex of the polymer in advance and impregnating the latex with the oil-soluble compound is preferable.

  The latex means that the polymer insoluble in the aqueous medium is dispersed as fine particles in the aqueous medium. As the dispersion state, the polymer is emulsified in the aqueous medium, emulsion-polymerized, micelle-dispersed, or the polymer has a partially hydrophilic structure in the molecule. Any of those in which the chains themselves are molecularly dispersed may be used.

Here, a method for preparing the polymer latex in advance and impregnating it with the oil-soluble compound 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 compound 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.
A second example of this method is a first step of preparing a polymer latex, a colorant-containing liquid in which the oil-soluble compound 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. The method includes a first step of preparing a polymer latex and a second step of preparing a fine particle dispersion by dispersing a disperse dye in the polymer latex.

  The particle size of the polymer latex fine particles is 0.001 to 0.5 μm, preferably 0.003 to 0.3 μm, and more preferably 0.003 to 0.2 μm.

Next, a method for emulsion polymerization in the presence of the monomer and the oil-soluble compound in the presence of the latex will be described.
Latex is generally produced using water, a monomer, a polymerization initiator, and a surfactant as main components. This monomer is dissolved in a water-soluble organic solvent such as THF (tetrahydrofuran) or ethanol and added dropwise. Is possible.
The oil-soluble compound and the monomer are co-dissolved in the organic solvent in advance and added dropwise, and the same polymerization operation can be performed.
In addition to this step, an organic solvent in which only the oil-soluble compound is dissolved may be added dropwise to adjust the colorant fine particle dispersion. For general emulsion polymerization operation method and principle, see Soichi Muroi “Chemistry of Polymer Chemistry Latex” Polymer Publications.

Next, the co-emulsification dispersion method will be described.
A first example of this method is a first step of preparing a polymer colorant mixture in which the oil-soluble compound and the dispersible polymer are dispersed or dissolved in an organic solvent, and the polymer colorant mixture and at least water. And a second step of preparing a fine particle dispersion by mixing with the liquid.
A second example of this method is a first step of preparing a liquid containing the oil-soluble compound dispersed or dissolved in an organic solvent, and a second step of preparing a polymer solution in which a dispersible polymer is dispersed or dissolved in an organic solvent. And a third step of preparing a fine particle dispersion by mixing the containing liquid, the polymer solution, and a liquid containing at least water.
A third example of this method is to prepare a liquid dispersion in which the oil-soluble compound is dispersed or dissolved in an organic solvent, and to mix the liquid mixture and a liquid containing at least water to prepare a fine particle dispersion liquid. And a second step of preparing a polymer fine particle dispersion by preparing a polymer solution in which a dispersible polymer is dispersed or dissolved in an organic solvent, and mixing the polymer solution with a liquid containing at least water. And a third step of preparing a fine particle dispersion by mixing the dispersion and the polymer fine particle dispersion.
In a fourth example of this method, a liquid containing the oil-soluble compound dispersed or dissolved in an organic solvent is prepared, and the liquid containing at least water is mixed to prepare a 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 a third step of preparing a fine particle dispersion by mixing the fine particle dispersion and the polymer solution. including.
A fifth example of this method is a step of directly preparing a fine particle dispersion by mixing the oil-soluble compound and the dispersible polymer with a liquid containing at least water.

  In the fine particle dispersion, the amount of the polymer used is preferably 10 to 900 parts by weight, and more preferably 50 to 600 parts by weight with respect to 100 parts by weight of the oil-soluble compound. When the proportion of the polymer used is less than 10 parts by mass, fine and stable dispersion tends to be difficult. When it exceeds 900 parts by mass, the proportion of the oil-soluble compound in the fine particle dispersion decreases, and the fine particle dispersion is reduced. When used as a water-based ink, there is a tendency that there is no room for formulation design.

  In the fine particle dispersion, the content of the fine particles 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 volume average particle size of the fine particles is preferably 0.001 to 0.5 μm, more preferably 0.003 to 0.3 μm, and particularly preferably 0.003 to 0.2 μm. 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.

-Organic solvent-
The organic solvent used for producing the fine particle dispersion is not particularly limited and can be appropriately selected based on the solubility of the oil-soluble compound or the polymer. For example, acetone, methyl ethyl ketone, diethyl ketone, etc. Ketone solvents, alcohol solvents such as methanol, ethanol, 2-propanol, 1-propanol, 1-butanol and tert-butanol, chlorine solvents such as chloroform and methylene chloride, aromatic solvents such as benzene and toluene, acetic acid Examples thereof include ester solvents such as ethyl, 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 100 to 500 parts by mass with respect to 100 parts by mass of the polymer.
100-300 mass parts is more preferable.
When the amount of the organic solvent used is 100 to 200 parts by mass, the polymer or the oil-soluble compound tends to be dissolved or dispersed favorably, and the necessity for the desolvation and concentration steps tends to be eliminated.

  When the vapor pressure of the organic solvent is higher than that of water, the organic solvent is preferably removed from the viewpoint of stability of the fine particle dispersion and safety and hygiene. 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 fine particle dispersion 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 neutralizer, a hydrophobic high-boiling organic solvent, a dispersant, and a dispersion stabilizer.

When the polymer has an unneutralized dissociable group, the neutralizing agent may be suitably added and used in terms of pH adjustment of the fine particle dispersion, self-emulsifying property, imparting dispersion stability, and the like. it can.
Examples of the neutralizing agent include organic bases and inorganic alkalis.

Examples of the organic base include triethanolamine, diethanolamine, N-methyldiethanolamine, and dimethylethanolamine.
Examples of the inorganic alkali include alkali metal hydroxides (for example, sodium hydroxide, lithium hydroxide, and potassium hydroxide), carbonates (for example, sodium carbonate, sodium hydrogen carbonate, and the like), ammonia, and the like.
From the viewpoint of improving the dispersion stability in the fine particle dispersion, the neutralizing agent is preferably added so as to have a pH of 4.5 to 10.0, and is preferably added so as 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 fine particle dispersion. 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 hydrophobic high-boiling solvent used is not particularly limited as long as it is within the range not impairing the effects of the present invention, but is preferably 0 to 1000 parts by weight, and preferably 0 to 300 parts by weight with respect to 100 parts by weight of the polymer. Part is more preferred.

The dispersant and / or dispersion stabilizer may be added to any of the polymer latex, the fine particle dispersion, a liquid containing at least water, and the polymer latex and / or the colorant fine particle dispersion is prepared. It is preferable to add to the aqueous solution of the previous step.
Examples of the dispersant and dispersion stabilizer include cation, anion, and nonionic surfactants, water-soluble or water-dispersible low molecular compounds, oligomers, and the like. As addition amount of the said dispersing agent and a dispersion stabilizer, it is 0-100 mass% with respect to the sum total of the said oil-soluble compound and the said polymer, and 0-20 mass% is preferable.

-Use of fine particle dispersion-
The fine particle dispersion of the present invention can be used in various fields, and is suitable for aqueous writing ink, aqueous printing ink, information recording ink (thermal, piezoelectric, electric field or acoustic ink jet method) and the like. It can be particularly suitably used for the ink of the present invention.

  When the fine particle dispersion is used as an ink for a writing water-based ink, a water-based printing ink, an information recording ink (thermal, piezoelectric, electric field or acoustic ink jet method), the recording material of the ink is not particularly limited. For example, plain paper, resin-coated paper, ink jet paper, film, electrophotographic co-paper, fabric, glass, metal, ceramics and the like can be mentioned.

(Ink, inkjet recording method, and recording material)
The ink of the present invention preferably contains the fine particle dispersion, and further contains other additives appropriately selected as necessary.

-Other additives-
Other additives include water-soluble organic solvents, surface tension modifiers, drying inhibitors, penetration enhancers, antioxidants, antifungal agents, pH modifiers, antifoaming agents, viscosity modifiers, dispersants, and dispersion stabilizers. Known additives such as an agent, a rust preventive agent, a chelating agent, and an ultraviolet absorber, which are described in paragraph numbers (0217) to (0226) and (0247) of JP-A No. 2001-279141, and Known compounds described in Japanese Laid-Open Patent Publication No. 2001-181549 can be used.

The water-soluble organic solvent is used for the purpose of a drying inhibitor and a penetration accelerator. 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. Furthermore, 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 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.

  The inkjet recording method of the present invention includes a step of recording an image on a recording material using the ink. The recording material is preferably a recording material provided with a porous ink receiving layer containing inorganic fine particles, and more preferably recording paper.

-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. Use of coated paper as the recording material is preferable because the image quality is improved. As the recording material, those described in paragraph numbers (0228) to (0246) of JP-A Nos. 2001-181549 and 2001-279141 can be used.

  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 (B-1))-
300 ml of distilled water is put into a 500 ml round bottom flask equipped with a stirrer, a thermometer and a nitrogen introduction tube, and the mixture is heated and stirred to an internal temperature of about 75 ° C. To this is added 50 mg of potassium persulfate dissolved in 4 ml of distilled water, and then a solution of 10 g of butyl acrylate in 50 ml of ethanol is added dropwise over 15 minutes. After stirring for 1 hour, ethanol is distilled off at an external temperature of 115 ° C. The reaction solution is cooled to room temperature, and the pH of the solution is adjusted to 6-7 with 1/10 M NaOH aqueous solution to obtain a latex. The particle size (volume average particle size) of the latex fine particles was 0.12 μm according to LB500 (manufactured by Horiba Seisakusho). Moreover, when the molecular weight was analyzed by GPC, the number average molecular weight was 9700. The GPC calibration curve was prepared using polystyrene as a standard material.
3 g of an oil-soluble dye (M-1) is dissolved in 10 cc of THF, mixed with the latex (latex fine particle size 0.12 μm), stirred for 1 hour, and a fine particle dispersion (B-1) containing an oil-soluble dye. ) The average particle size of the fine particle dispersion (B-1) was 0.13 μm according to LB500 (manufactured by Horiba Seisakusho). The GPC was performed using LC-10AD (manufactured by Shimadzu Corporation), and the following examples and comparative examples were also the same.

-Production Example 2 (Preparation of fine particle dispersion (B-2))-
A latex (latex fine particle size 0.08 μm) was produced in the same manner as in Production Example 1 except that butyl acrylate / ethyl acrylate = 5 g / 5 g was used instead of 10 g of butyl acrylate of Production Example 1, and an oil-soluble dye ( M-1) was mixed in the same manner to obtain a fine particle dispersion (B-2). The average particle size of the fine particle dispersion (B-2) was 0.095 μm according to LB500 (manufactured by Horiba Seisakusho).

-Production Example 3 (Preparation of fine particle dispersion (B-3))-
A latex (latex fine particle size 0.06 μm) was produced in the same manner as in Production Example 1 except that butyl acrylate / ethyl acrylate / styrene = 5 g / 3 g / 2 g was used instead of 10 g of butyl acrylate of Production Example 1. The oil-soluble compound (M-1) was mixed in the same manner to obtain a fine particle dispersion (B-3). The average particle size of this latex dispersion (B-3) was 0.072 μm according to LB500 (manufactured by Horiba Seisakusho).

-Production Example 4 (Preparation of fine particle dispersion (B-4))-
Latex was prepared in the same manner as in Production Example 1 except that 10 g of butyl acrylate of Production Example 1 was replaced with methacrylate = 5 g / 4 g / 1 g of butyl acrylate / styrene / polyethylene glycol monomethyl ether (ethyleneoxy chain repeat number: about 23). (Latex fine particle diameter 0.08 μm) was produced, and the oil-soluble compound (M-1) was similarly mixed to obtain a fine particle dispersion (B-4). The average particle size of the fine particle dispersion (B-4) was 0.082 μm according to LB500 (manufactured by Horiba Seisakusho).

-Production Example 5 (Preparation of fine particle dispersion (B-5))-
A latex (latex fine particle size 0.06 μm) was produced in the same manner as in Production Example 1 except that butyl acrylate / acrylic acid = 8 g / 2 g was used instead of 10 g of butyl acrylate of Production Example 1, and an oil-soluble compound (M-1) was mixed in the same manner to obtain a fine particle dispersion (B-5). The average particle diameter of the fine particle dispersion (B-5) was 0.065 μm according to LB500 (manufactured by Horiba Seisakusho).
Table 1 shows the results of the latex constituent polymer, the oil-soluble compound and the fine particle dispersion used in Production Examples 1 to 5. Evaluation of the obtained fine particle dispersion was performed as follows.

-Production Example 6 (Preparation of fine particle dispersion (B-6))-
Latex (latex fine particle size 0.06 μm) in the same manner as in Production Example 1 except that the electron-donating colorless dye (N-1) was used instead of the oil-soluble dye (M-1) in Production Example 1. And an electron-donating colorless dye (N-1) was mixed in the same manner to obtain a fine particle dispersion (B-6). Here, the compound (N-1) is a compound shown below. The average particle size in each fine particle dispersion was measured in the same manner as shown in Table 1.
Table 1 shows the results of the latex constituent polymers, oil-soluble compounds and fine particle dispersions used in Production Examples 1-6. Evaluation of the obtained fine particle dispersion was performed as follows.

<Dispersed state evaluation>
1) Dispersion stability The fine particle dispersions obtained in Production Examples 1 to 5 were confirmed to have a particle size of 0.2 μm or less by a particle size measurement test using a particle size measuring device, and there was no aggregate by visual observation. Judged whether or not.

2) Storage stability Whether the particle size of the fine particle dispersion obtained in Production Examples 1 to 5 is increased due to aggregation or the particle size distribution is not expanded by a storage test at room temperature for 7 days. It was judged.
The dispersion stability and storage stability test results were evaluated according to the following criteria.
Good: There is almost no aggregation in dispersion, and the particle size is 0.2 μm or less.
Poor: Aggregation occurs during dispersion holding and storage, and the particle size distribution spreads.

  As is clear from the results in Table 1, a fine particle dispersion having a small particle size, no aggregation, and excellent dispersion stability and storage stability can be produced.

[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 (B-1) 50 parts ・ Diethylene glycol 5 parts ・ Glycerin 18 parts ・ Diethanolamine 1 part ・ Orphine E1010 (surfactant, manufactured by Nissin Chemical Industry Co., Ltd.) 0.9 part ・ Water total 100 parts amount

<Preparation of inks 02 to 05>
In the production of the ink 01, the ink 01 was used except that the fine particle dispersion (B-1) was replaced with the fine particle dispersion (B-2 to 5) prepared in Production Examples 2 to 5 of Example 1. Water-based inkjet recording inks 02 to 05 were prepared in the same manner as in the above.

<Preparation of Comparative Example Ink-1>
The following materials were mixed and filtered through a 0.45 μm filter to prepare a comparative ink-1 as an aqueous inkjet recording ink.
・ 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 (surfactant, manufactured by Nissin Chemical Industry Co., Ltd.) 0.2 part ・Amount of water 100 parts

-Image recording and evaluation-
The prepared inks 01 to 05 are filled in a cartridge of an ink jet printer MC-2000 (manufactured by EPSON), and using the same machine, PPC plain paper and ink jet paper photo glossy paper EX (Fuji Photo Film Co., Ltd.) An image was recorded on the product and the following evaluation was performed. 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.

<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 has been 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 by a reflection densitometer (X-Rite310TR, X- Rite), and evaluated 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>
About ozone resistance, the density | concentration before and behind storing a sample for 3 days on the conditions of ozone density | concentration of 1.0 ppm was measured in X-rite 310 (made by X-Rite), and the dye residual rate was calculated | required and evaluated.
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 clear from the results in Table 2, the inkjet recording inks of the examples have excellent printing performance, no paper dependency, and excellent water resistance, high scratch resistance, light resistance, light resistance, and ozone resistance. On the other hand, although the printing performance and scratch resistance are not changed in the comparative example, it can be seen that other performances, particularly ozone resistance, water resistance, and light resistance are remarkably inferior.

Claims (7)

A dispersion containing fine particles characterized by containing an oil-soluble compound in latex fine particles composed of a polymer having a hydrophobic polymer portion alone or a polymer having a hydrophobic polymer portion and a hydrophilic polymer portion. The dispersion containing fine particles according to claim 1, wherein the hydrophilic polymer portion is anionic, nonionic, or a mixed type thereof. The dispersion containing fine particles according to claim 1 or 2, wherein the oil-soluble compound is an oil-soluble dye. The dispersion containing fine particles according to claim 3, wherein the oxidation potential of the oil-soluble dye is nobler than 1.0 V (vs SCE). An ink comprising a dispersion containing the fine particles according to any one of claims 1 to 4. An inkjet recording method comprising a step of recording an image on a recording material using the ink according to claim 5. 7. The ink jet recording method according to claim 6, wherein the recording material is a recording material provided with a porous ink receiving layer containing inorganic fine particles.