JP2006022261A - Ink composition and inkjet recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink composition providing an ink for inkjet recording, having excellent jetting stability at a jetting nozzle part, having a color tone (hue) hardly depending on a material to be recorded, and ink penetrability, and providing an image having excellent water resistance, weather resistance (especially light resistance and ozone resistance) and abrasion resistance, and enabling the high-density and high-quality image to be recorded. <P>SOLUTION: The ink composition contains colored fine particles containing an oil having ≤2.60×10<SP>-13</SP>[m<SP>3</SP>(STP)×m/(s×m<SP>2</SP>×kPa)] coefficient of oxygen permeability at 25°C, and water-insoluble dye or pigment in an aqueous medium. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink composition and an ink jet recording method using the same, and more particularly to an ink composition containing colored fine particles composed of a specific oil and an ink jet recording method using the same.

  In recent years, with the spread of computers, ink jet printers are widely used for printing on paper, film, cloth, etc. not only in offices but also in general households. Oil-based inks, water-based inks, and solid inks are known as inks for ink-jet recording. Among these, water-based inks are advantageous in terms of ease of production, handling, odor, safety, and the like. Water-based ink has become mainstream.

However, many of the water-based inks use a water-soluble dye that dissolves in a molecular state, and thus have an advantage of high transparency and color density. However, since the dye is water-soluble, the water resistance is poor, so-called When printing on plain paper, bleeding (bleeding) occurs, the printing quality is remarkably deteriorated, the light resistance is inferior, and the recording paper is provided with an ink-receptive recording layer having porous inorganic fine particles on the surface. (Hereinafter sometimes referred to as “photo quality paper”), the problem is that the image storability is significantly deteriorated due to the influence of an oxidizing gas (SO _x , NO _x , ozone, etc .; the same shall apply hereinafter). Had.

  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, in the case of this water-based ink, although the water resistance is improved to some extent, it is difficult to say that it is sufficient, and the storage stability of the pigment or disperse dye dispersion in the water-based ink is lacking, which causes clogging at the ink discharge port. There are problems such as easy. Further, when photographic image quality paper is used, there is a problem that inks using pigments and dyes have poor permeability and the pigments and dyes are easily peeled off from the surface when rubbed by hand, that is, they are poor in scratch resistance.

  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 3). However, the ink for ink jet recording obtained by this method has insufficient color tone, insufficient color reproducibility, and in particular, insufficient image durability when exposed to an oxidizing gas, etc. Is not sufficiently scratch resistant when printed on photographic quality paper. There is also a proposal regarding a method for preventing oxidative degradation due to oxygen in the air of the fluorescent dye by covering the fluorescent dye with a resin having low oxygen permeability (see, for example, Patent Document 4). This is simply a resin and a fluorescent dye added to a certain solvent so as to cover the color tone and color reproducibility in the same manner as described above, and this method is used to suppress discoloration of colored compounds containing dyes or pigments. There is no example to apply to the application.

In addition, there is also a proposal related to an ink that has improved colorability and scratch resistance by introducing a salt-forming group and a polyalkylene oxide group into the polymer (see, for example, Patent Document 5). However, although this ink has good scratch resistance by fingers, it cannot satisfy the high level of scratch resistance as in the case of eraser rubbing. 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 6), but in applications that require a high level of image durability. Was insufficient.
JP-A-56-157468 JP 58-45272 A JP 62-241901 A JP 2002-179968 A Japanese Patent Laid-Open No. 2001-123097 JP 2001-262018 A

  As described above, it has handleability, odor, and safety, and has excellent dispersion stability and storage stability when it has a small particle size, and has an eye at the tip of the discharge nozzle when applied to ink. No clogging, excellent ejection stability, no paper dependency, good color development and color tone (hue), excellent ink penetration even when using photographic quality paper, water resistance after recording, especially weather resistance (especially light resistance) Ink composition, ozone resistance), scratch resistance, and high density and high image quality recording (especially prepared as a fine particle dispersion) have not yet been provided. is there.

  The present invention has been made in view of the above, has handleability, odor and safety, and has a small particle size and liquid stability (dispersibility, storage stability over time), and an ink jet recording ink. Excellent discharge stability of the discharge nozzle part, and has a color tone (hue) that does not depend on the recording material, ink permeability, water resistance of the image, weather resistance (particularly light resistance, ozone resistance), and An ink composition that is excellent in scratch resistance and enables high-density and high-quality image recording, and the ink composition is used, has handleability, odor and safety, and has an eye in the discharge nozzle section. An object of the present invention is to provide an ink jet recording method capable of stably performing high-density and high-quality image recording without clogging, and to achieve the object.

In the present invention, colored fine particles present in an aqueous medium (preferably dispersed) have an oxygen permeability coefficient at 25 ° C. of 2.60 × 10 ⁻¹³ [m ³ (STP) · m / (s · m ² · KPa)] The following oils are used together with water-insoluble dyes or pigments (hereinafter also referred to as “water-insoluble colorants”), so that the stability of the ink composition and the recorded image The inventors have obtained knowledge that it is particularly effective in terms of weather resistance, color reproducibility, gloss (ink permeability), and scratch resistance, and have been achieved based on such knowledge. Specific means for achieving the above object are as follows.

<1> At least an aqueous medium, an oil having an oxygen permeability coefficient at 25 ° C. of 2.60 × 10 ⁻¹³ [m ³ (STP) · m / (s · m ² · kPa)] or less, and water-insoluble And an ink composition comprising colored fine particles containing a functional dye or pigment.
<2> The ink composition according to <1>, wherein the oil has a softening start temperature of 25 ° C. or lower.
<3> The ink composition according to <1> or <2>, wherein the oil includes a polymer component.
<4> The ink composition according to <3>, wherein the polymer component has a glass transition temperature of 25 ° C. or lower.
<5> The ink composition according to any one of <1> to <4>, which is used for inkjet recording.

<6> An inkjet recording method, wherein an image is recorded on a recording material using the ink composition according to any one of <1> to <5>.
<7> The inkjet recording method according to <6>, wherein the recording material is a paper material, a resin material, or a cloth material.

  According to the present invention, it has handleability, odor, and safety, and has a small particle size, liquid stability (dispersibility, storage stability over time), and a discharge nozzle portion when an ink for ink jet recording is used. Excellent discharge stability, recording material-independent color tone (hue), ink permeability, excellent image water resistance, weather resistance (especially light resistance, ozone resistance), and scratch resistance, high Ink composition that enables high-quality image recording at a density, and the ink composition is used, has handleability, odor and safety, and is not clogged at the discharge nozzle. In addition, it is possible to provide an ink jet recording method capable of stably performing high-density and high-quality image recording.

In the present invention, the colored fine particles contained in the aqueous medium (preferably dispersed) have an oxygen permeability coefficient at 25 ° C. of 2.60 × 10 ⁻¹³ [m ³ (STP) · m / (s · m ² · kPa)] or less oil is used. Hereinafter, the ink composition of the present invention and the ink jet recording method using the same will be described in detail.

  The ink composition of the present invention contains at least colored fine particles in an aqueous medium, and the containing form is not particularly limited, but the composition is obtained by so-called emulsifying and dispersing colored fine particles in an aqueous medium. Is preferred. Moreover, it can comprise using various additives etc. as needed other than a coloring microparticle and an aqueous medium. Various additives and the like may be added separately from the aqueous medium and the colored fine particles, or may be included in the preparation of the aqueous medium and the colored fine particles.

[Colored fine particles]
The colored fine particles according to the present invention have an oxygen permeability coefficient at 25 ° C. of 2.60 × 10 ⁻¹³ [m ³ (STP) · m / (s · m ² · kPa)] or less, water-insoluble A dye or pigment (a water-insoluble colorant) at least, and can generally be constituted using an organic solvent. If necessary, in addition to the oil and the dye or pigment, a water-soluble organic solvent or a surface tension modifier. It can be configured using various additives such as liquid or solid.

(oil)
The ink composition of the present invention has an oil permeation coefficient at 25 ° C. of 2.60 × 10 ⁻¹³ [m ³ (STP) · m / (s · m ² · kPa)] or less (hereinafter “book” Also referred to as “oil according to the invention”). Particularly in the present invention, by using such a low oxygen permeable oil together with a water-insoluble colorant, it is possible to form a state where the water-insoluble colorant is covered with the oil, thereby impairing color tone and color reproducibility. In addition, the fading of dyes and pigments after recording can be effectively suppressed. In other words, since the gas barrier property near the dye or pigment is improved, contact with oxidizing gas (oxygen, SO _x , NO _x , ozone, etc.) in the air is suppressed, and color material fading is suppressed. It is. Therefore, it is possible to constitute an ink composition having excellent image storability (particularly light resistance and ozone resistance) after recording.

  In addition to the improvement in image storability as described above, by using the oil according to the present invention together with a water-insoluble colorant, the color tone (hue) independent of the recording material, ink permeability, image water resistance, and The scratch resistance of the image can also be effectively improved. Further, for example, when a water-insoluble colorant is dispersed and contained, the dispersion stability and storage stability of the dispersion can be improved while reducing the diameter of the dispersed particles (preferably with a diameter of 1 μm or less). In addition, when applied to an inkjet recording application, stable ink discharge without clogging at the tip of the discharge nozzle portion becomes possible. Therefore, it is possible to stably record a high-quality image that is robust, has high density, and good gloss.

The oxygen permeability coefficient of the oil according to the present invention can be measured at 25 ° C. using a known oxygen electrode method. The method for measuring the oxygen permeation coefficient of organic compounds is described in the book, and is described in detail, for example, in “Polymers and Water” (edited by the Society of Polymer Science, p. 283 to 323, published by Koshobo, Showa 47). Yes. The value of the oxygen permeation coefficient defined in the present invention is calculated using an oxygen electrode method capable of measuring fluid oil. The oxygen permeability coefficient [unit: m ³ (STP) · m / (s · m ² · kPa)] was measured using an oxygen analyzer (model 3600 [diaphragm 2956A 25 μm], manufactured by Orbis Fair Laboratories Japan Inc.). The oil to be measured is fixed in a uniform film shape on the detection head under the conditions of 25 ° C. and humidity 50 RH%, and the oxygen concentration detected by the electrode is calibrated using a standard transmission sample.

  The oil according to the present invention can be suitably constituted by containing at least one polymer component. By configuring the oil with a polymer component instead of a low molecular component, the oxygen permeability coefficient tends to be lower than when using a low molecular component, so the percentage of the polymer component contained in the oil is high. It is desirable. From this viewpoint, the content of the polymer component in the oil is preferably 10 parts by mass or more, and more preferably 50 parts by mass or more with respect to 100 parts by mass of the oil.

  The oil which concerns on this invention can be comprised using the low molecular oil whose boiling point is 110 degreeC or more as needed at least 1 type selected from an oil-soluble polymer. In some cases, two or more kinds of polymer components may be used in combination. The oil according to the present invention may be in a solid form, but preferably has fluidity. Hereinafter, the polymer component will be described in detail.

<Oil-soluble polymer>
The oil-soluble polymer can be prepared as an oil having an oxygen permeability coefficient at 25 ° C. of 2.60 × 10 ⁻¹³ [m ³ (STP) · m / (s · m ² · kPa)] or less. A polymer having any structure can be selected. The oil solubility here means a property that the solubility in distilled water at 25 ° C. is 10% or less, and as an oil-soluble polymer according to the present invention, from the viewpoint of dispersibility when dispersed in an aqueous medium, A polymer insoluble in an aqueous medium is preferably used.

  Examples of the oil-soluble polymer (hereinafter also simply referred to as “polymer”) include conventionally known polymers such as vinyl polymers and condensation polymers (for example, polyurethane, polyester, polyamide, polyurea, polycarbonate). The polymer bonding form may be any of homopolymer, random copolymer, alternating copolymer, block copolymer, graft copolymer, star copolymer, dendrimer, hyperbranched polymer, etc. What introduced the functional group can also be used.

From the viewpoint of imparting scratch resistance, the polymer is preferably selected from those capable of having a softening start temperature of 25 ° C. or lower when oil is used. Further, from the viewpoint of improving scratch resistance, a polymer having a glass transition temperature (Tg) of 25 ° C. or lower is preferable, a polymer having 0 ° C. or lower is more preferable, a polymer having −25 ° C. or lower is further preferable, and −40 Most preferred are polymers that are below ℃.
If the Tg of the polymer exceeds 25 ° C., the scratch resistance of the image is insufficient when recording is performed using photographic quality paper which is difficult to ensure scratch resistance unless other polymers and low molecular oils described below are used in combination. It may become.

From the viewpoint of weather resistance, the weight average molecular weight (Mw) of the polymer is such that the oxygen permeability coefficient of the oil when measured at 25 ° C. is 2.60 × 10 ⁻¹³ [m ³ (STP) · m / (s · m ² · kPa)], the molecular weight is not particularly limited as long as it is within the range of 1000 to 200000, particularly 2000 to 50000. When Mw is less than 1000, it tends to be difficult to obtain a stable colored fine particle dispersion when the dispersion is prepared, and when it is greater than 200000, the solubility in an organic solvent is deteriorated or when it is dissolved in an organic solvent. There is a tendency that the solution viscosity increases and it becomes difficult to separate.
Further, from the viewpoint of improving ink permeability, Mw is preferably smaller, specifically, preferably 100,000 or less, more preferably 50000 or less, and particularly preferably 2000 to 40000.

The polymer polymerization form is preferably vinyl polymerization from the viewpoint of the degree of freedom in polymer design.
Examples of the monomer constituting the polymer include the following, and the polymer can be constituted by copolymerizing at least one of these or, if necessary, two or more of them.

  That is, as the monomer, acrylic acid ester or methacrylic acid ester [the terminal group of the ester bond may have an aliphatic group which may have a substituent or an aromatic group which may have a substituent. Examples of these include 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, alkoxymethyl group, alkoxyethyl 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-tetramethylphenyl group, 4-chlorophenyl group, phenoxymethyl group, phenoxyethyl group, glycidylalkyl group, glycidyl group, Glycidyloxybutyl group, glycidyloxyethyl group, glycidylpropyl group, hydroxyalkyl group, 2-hydroxyethyl group, hydroxypropyl group, 2-hydroxybutyl group, 4-hydroxybutyl group, 3-hydroxypropyl group, dimethylamino Ethyl group, diethylaminoethyl group, dimethylaminopropyl group, diethylaminopropyl group, trimethoxysilylpropyl group, trimethylsilylpropyl group, polyethylene oxide monomethyl ether group, oligoethylene oxide monomethyl ether group, Oxide group, an oligo ethylene oxide group, oligoethylene oxide monoalkyl ether groups, polyethylene oxide monoalkyl ether groups, polypropylene oxide monoalkyl ether groups, such as an oligo propylene oxide monoalkylether group, and also include acrylic acid and methacrylic acid. Among these, n-butyl group, tert-butyl group, 2-chloroethyl group, phenoxyethyl group, glycidyl group, 2-hydroxyethyl group, and 4-hydroxybutyl group are preferable. ];

  Acrylamides, methacrylamides [specifically, N-monosubstituted acrylamide, N-disubstituted acrylamide, N-monosubstituted methacrylamide, N-disubstituted methacrylamide (the substituent has a substituent) May be an aliphatic group which may have a substituent or an aromatic group which may have a substituent, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an 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, butoxymethyl group, etc.). . ];

  Olefins [Specific examples include dicyclopentadiene, ethylene, propylene, 1-butene, 1-pentene, vinyl chloride, vinylidene chloride, isoprene, chloroprene, butadiene, and 2,3-dimethylbutadiene. ];

  Styrene (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) 3-methylstyrene, 4-methylstyrene, 3-ethylstyrene, 4-ethylstyrene, 3-propylstyrene, 4-propylstyrene, 3-butylstyrene, 4-butylstyrene, 3-hexylstyrene, 4-hexylstyrene 3-octyl styrene, 4-octyl styrene, 3- (2-ethylhexyl) styrene, 4- (2-ethylhexyl) styrene, allyl styrene, isopropenyl styrene, butenyl styrene, octenyl styrene And the like. ];

  Vinyl ethers [Specific examples include methyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, methoxy vinyl ether, 2-ethylhexyl vinyl ether, and the like. ];

  And 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, methoxy Ethyl vinyl ketone, N-vinyl oxazolidone, N-vinyl pyrrolidone, vinylidene chloride, methylene malonnitrile, vinylidene, diphenyl-2-acryloyloxyethyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, dibutyl-2-acryloyloxyethyl Examples thereof include phosphate, dioctyl-2-methacryloyloxyethyl phosphate, and the like.

  In the case where the polymer according to the present invention is one that can have a softening start temperature (Tg) of the oil of 25 ° C. or less when prepared into an oil, For various purposes (for example, adjustment of solubility, compatibility with oil-soluble dyes, dispersion stability, etc.), it is also preferable to employ a configuration in which two or more kinds are used in combination.

  When the polymer uses, for example, acrylic acid esters or methacrylic acid esters as the monomer, from the viewpoint of lowering Tg to the above range, the terminal group of the ester bond is an aliphatic group having 1 to 20 carbon atoms, or 7 carbon atoms. It is preferable to include acrylic acid esters or methacrylic acid esters which are an alkyl-substituted aromatic group or -30-substituted aromatic group, and the terminal group of the ester bond is an aliphatic group having 2 to 20 carbon atoms. More preferably, acrylic acid esters and methacrylic acid esters are included, and further hexyl methacrylate, 2-ethylhexyl methacrylate, butyl methacrylate, isobutyl methacrylate, s-butyl methacrylate, 2-ethylhexyl methacrylate, ethyl acrylate, propyl acrylate, butyl acrylate ,I More preferably, it includes butyl acrylate, s-butyl acrylate, hexyl acrylate, or 2-ethylhexyl acrylate, at least of hexyl methacrylate, butyl acrylate, isobutyl acrylate, s-butyl acrylate, propyl acrylate, hexyl acrylate, and 2-ethylhexyl acrylate It is particularly preferable to include one kind.

  In addition, from the viewpoint of reducing oxygen permeability (oxygen permeability coefficient at 25 ° C.), the polymer may contain N-monosubstituted acrylamide, N-disubstituted acrylamide, N-monosubstituted methacrylamide, N-disubstituted as the monomer. Substituted methacrylamide, glycidyl acrylate, glycidyl methacrylate, hydroxyethyl acrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl acrylate glycidyl ether, 2-chloroethyl acrylate, 3-chloro-2-hydroxypropyl methacrylate, Those containing at least one of 2,3-dihydroxypropyl methacrylate, 2-hydroxybutyl acrylate, and 2-hydroxypropyl acrylate are preferred.

  Among the above, as a preferred polymer, a copolymer comprising two or more of acrylic acid ester and / or methacrylic acid ester, at least one of acrylic acid ester or methacrylic acid ester and (preferably N-mono-substituted) acrylamide is preferred. A copolymer of at least one of acrylic ester or methacrylic ester with acrylonitrile or methacrylonitrile, a copolymer of at least one of acrylic ester or methacrylic ester with a styrene derivative, acrylic ester Alternatively, a copolymer of at least one of methacrylic acid ester and vinyl ether, or a copolymer of at least one of acrylic acid ester or methacrylic acid ester and vinyl chloride or vinylidene chloride can be given.

The polymer according to the present invention may include a hydrophilic portion in the polymer, and the hydrophilic portion is any of a cationic portion, an anionic portion, a nonionic portion, or a mixed type portion thereof. However, those containing an anionic site, a nonionic site, or a mixed type site thereof are preferable.
Examples of the polymer containing a cationic site include a polymer containing a cationic dissociation group such as a tertiary amino group and pyridine, and examples of the polymer containing an anionic site include anionic properties such as carboxylic acid and sulfonic acid. Examples thereof include polymers containing a dissociating group, and examples of polymers containing a nonionic moiety include polymers containing a nonionic dispersible group such as an ethyleneoxy group, a hydroxyl group, and a pyrrolidone group.
In order to introduce a hydrophilic site into the polymer, one kind of raw material may be used as necessary, or for various purposes (the stability of the dispersion in each aqueous medium, the dissolution of the polymer for producing the dispersion). Two or more kinds of raw materials may be used for adjustment of the property.

  Further, in the above, when the dissociable group is an anionic dissociable group, the dissociable group may be an alkali metal (for example, Na, K, etc.) or a salt of ammonium ion. In some cases, the dissociable group 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.).

Hereinafter, although the specific example (PA-01-PA-11) of a polymer is enumerated, in this invention, it is not limited to these specific examples. In addition, the ratio in a parenthesis means mass ratio, Mw represents a weight average molecular weight.
(PA-01) n-butyl acrylate / 2-hydroxyethyl acrylate copolymer [70/30, Mw = 24300]
(PA-02) n-butyl acrylate / 4-hydroxybutyl acrylate copolymer [70/30, Mw = 22200]
(PA-03) n-butyl acrylate / 2-chloroethyl acrylate copolymer [70/30, Mw = 30600]
(PA-04) n-butyl acrylate / glycidyl methacrylate copolymer [70/30, Mw = 33000]
(PA-05) n-butyl acrylate / 4-hydroxybutyl acrylate glycidyl ether copolymer [70/30, Mw = 18200]
(PA-06) n-butyl acrylate / phenoxyethyl acrylate copolymer [70/30, MW = 18500]
(PA-07) n-butyl acrylate / t-butyl acrylamide copolymer [90/10, Mw = 30600]
(PA-08) n-butyl acrylate / N-isopropylacrylamide copolymer [90/10, Mw = 30300]
(PA-09) Methyl acrylate / M-90G (manufactured by Shin-Nakamura Chemical Co., Ltd.) copolymer [70/30, Mw = 25800]
(PA-10) n-butyl acrylate / N-isopropylidacrylamide copolymer [70/30, Mw = 30600]
(PA-11) n-butyl acrylate / t-butyl acrylamide copolymer [50/50, MW = 25900]

<Low molecular oil>
In the present invention, at least one low molecular weight oil can be used in combination with the oil-soluble polymer. For low molecular weight oils, the oxygen permeation coefficient at 25 ° C as a whole should be 2.60 × 10 ^-13 [m ³ (STP) · m / (s · m ² · kPa)] or less. There are no particular limitations on the structure, not only as a dispersion medium for water-insoluble dyes or pigments, but also from the viewpoint of adjusting the viscosity, specific gravity, and recording performance of the colored fine particle dispersion to be dispersed and prepared. Can be used.

  The low molecular oil is hydrophobic and preferably has a boiling point of 110 ° C. or higher, more preferably 150 ° C. or higher. In addition, an oil having a solubility in distilled water at 25 ° C. of 3% or less is preferred because low molecular oil does not dissolve when mixed with an aqueous medium. Specific examples include petroleum fractions (gasoline, light oil, kerosene, etc.), n-paraffin solvents (carbon number 8-15), aromatic hydrocarbon solvents (toluene, xylene, naphthalene, etc.), ketone solvents ( Methyl ethyl ketone, methyl isobutyl ketone, di-t-butyl ketone, etc.), ester solvents (ethyl acetate, butyl acetate, etc.), ether solvents (dibutyl ether, methyl ethyl ether, etc.), US Pat. No. 2,322,027 Hydrophobic high-boiling organic solvents described in the specification, Japanese Patent Application Laid-Open No. 2002-80772 (or Japanese Patent Application No. 2000-78531) and the like can be used. Examples of the hydrophobic high boiling point organic solvent include phosphoric acid triesters, phthalic acid diesters, alkylnaphthalenes, benzoic acid esters, and the like. These can be either liquid or solid at room temperature depending on the purpose. The amount used in the case of using a hydrophobic high boiling point organic solvent is not particularly limited as long as it is within the range not inhibiting the effect of the present invention, and is 0 to 1000 parts by mass with respect to 100 parts by mass of the oil-soluble polymer described above. Is preferable, and 0-300 mass parts is more preferable.

  In the present invention, as described above, the colored fine particles are preferably formed using an oil having a softening start temperature of 25 ° C. or lower. In this case, the softening start temperature is 25 ° C. or lower by mixing two or more kinds of oils. It can also be adjusted to. From the viewpoint of the scratch resistance after recording, the softening start temperature of the oil is preferably low, and more preferably 0 ° C. or less.

  In the ink composition of the present invention, the content of the polymer component 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 a dye (particularly an oil-soluble dye) or pigment. If the proportion of the polymer component 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 dye (particularly oil-soluble dye) or pigment in the ink composition is small. Thus, when the ink composition is used as a water-based ink, there is a tendency that there is no room for blending design.

  As content in the colored fine particle of the oil which concerns on this invention, 10-1000 mass parts is preferable with respect to 100 mass parts of the water-insoluble dye or pigment mentioned later, and 50-600 mass parts is more preferable. When the oil content is less than 10 parts by mass, fine and stable dispersion may tend to be difficult. When the oil content exceeds 1000 parts by mass, the ratio of the dye becomes too small, and it is formulated for use as an ink. There may be a tendency for the pigment to precipitate out of the upper margin.

(Water-insoluble dye or pigment)
The ink composition of the present invention contains at least one water-insoluble dye or pigment. First, the water-insoluble dye will be described in detail.
<dye>
In the present invention, the water-insoluble dye means a pigment that has an affinity for the above-described oil and hardly dissolves in an aqueous medium when colored fine particles containing the dye and the oil are dispersed in the aqueous medium. . More specifically, it means that the solubility in water at 25 ° C. (mass of dye dissolved in 100 g of water) is 1 g or less, preferably 0.5 g or less, more preferably 0.1 g or less. .
From the above, so-called oil-soluble dyes that are insoluble in water are preferably used.

In addition, a dye having a noble (high) oxidation potential is desirable in order to improve resistance to amber, particularly an oxidizing substance such as ozone, and curing characteristics. Therefore, as the oil-soluble dye, those having an oxidation potential nobler than 1.0 V (vs SCE) are more preferable. This oxidation potential is preferably higher, more preferably the oxidation potential is higher than 1.1 V (vs SCE), and particularly preferably higher than 1.15 V (vs SCE).
The above oxidation potential is described in detail 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.

  The oil-soluble dye can be appropriately selected from conventionally known compounds (dyes). Specifically, the dyes described in paragraphs [0023] to [0053] of JP-A No. 2002-114930 are used. Etc. In the ink composition of the present invention, the oil-soluble dye may be used alone or in combination of several kinds. Further, if necessary, colorants such as other water-soluble dyes, disperse dyes, and pigments may be contained.

Next, the oil-soluble dye will be described in detail for each color.
As the yellow oil-soluble dye, an oil-soluble dye represented by the following general formula (Y-I) is preferable. The oil-soluble dye represented by the general formula (Y-I) may be used not only for yellow but also for other colors such as black ink, green ink, and red ink.

A-N = NB ... General formula (Y-I)
In the general formula (Y-I), A and B each independently represent a heterocyclic group which may have a substituent. The heterocyclic ring is preferably a 5- or 6-membered heterocyclic ring, which may be a monocyclic structure or a polycyclic structure in which two or more rings are condensed, and is an aromatic heterocyclic ring. May also be 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, pyrazoloazoles, or a ring derived from meldrum acid, In addition, a condensed heterocyclic ring in which a hydrocarbon aromatic ring or a heterocyclic ring is further condensed to these rings is preferable. Among them, a ring derived from 5-pyrazolone, 5-aminopyrazole, pyridone and pyrazoloazoles is preferable, and a ring derived from 5-aminopyrazole, 2-hydroxy-6-pyridone and pyrazolotriazole is particularly preferable.

  Examples of the heterocyclic ring represented by B include pyridine, pyrazine, pyrimidine, pyridazine, triazine, quinoline, isoquinoline, quinazoline, cinnoline, phthalazine, quinoxaline, pyrrole, indole, furan, benzofuran, thiophene, benzothiophene, pyrazole, imidazole, Preferred examples include rings such as benzimidazole, triazole, oxazole, isoxazole, benzoxazole, thiazole, benzothiazole, isothiazole, benzoisothiazole, thiadiazole, benzisoxazole, pyrrolidine, piperidine, piperazine, imidazolidine and thiazoline. Among them, pyridine, quinoline, thiophene, benzothiophene, pyrazole, imidazole, benzimidazole, triazole, oxazole, isoxazole, benzoxazole, benzisoxazole, thiazole, benzothiazole, isothiazole, benzoisothiazole, thiadiazole, benzisoxazole The ring of quinoline, thiophene, pyrazole, thiazole, benzoxazole, benzisoxazole, isothiazole, imidazole, benzothiazole, thiadiazole is more preferable, and pyrazole, benzothiazole, benzoxazole, imidazole, 1,2,4 -Especially preferred are thiadiazole and 1,3,4-thiadiazole rings.

  Examples of the substituent that can be substituted for A and B include a halogen atom, an alkyl group, a cycloalkyl group, an aralkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, a cyano group, a hydroxyl group, a nitro group, and an alkoxy group. , Aryloxy 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 aryl Ruhoniru 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 formula (Y-II), (Y-III), or (Y-IV) are more preferable.

In the general formula (Y-II), R ¹ and R ³ are each independently 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 Represents an ionic hydrophilic 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, and 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. , R ⁶ represents a heterocyclic group. Za is -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 a nonmetallic Represents a substituent.

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, A carbamoyl group or an ionic hydrophilic group is represented. 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 Carbamoyl group, sulfamoyl group, sulfonyl group, acyl group, amino group, substituted amino group, hydroxy group, or ionic hydrophilic group. R ¹⁰ represents a heterocyclic group.

The groups 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 as follows. It will be described in detail.

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

The cycloalkyl group represented by R ¹ , R ² , R ³ , R ⁵ , R ⁷ , or 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. A specific example of the (substituted) cycloalkyl group is preferably a cyclohexyl group.

The aralkyl group represented by R ¹ , R ² , R ³ , R ⁵ , R ⁷ or 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 hydroxy group, an alkoxy group, a cyano group, a halogen atom, and an ionic hydrophilic group. Examples of the aryl moiety of the aralkyl group include a phenyl group and a naphthyl group, and specific examples of the (substituted) aralkyl group include a benzyl group and a 2-phenethyl group.

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

The alkylthio group represented by R ¹ , R ³ , R ⁵ , R ⁷ , R ⁸ , or 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 an ionic hydrophilic group. Specific examples of the (substituted) alkylthio group include a methylthio group and an ethylthio group.

The arylthio group represented by R ¹ , R ³ , R ⁵ , R ⁷ , R ⁸ , or R ⁹ includes an arylthio group having a substituent and an unsubstituted arylthio group. As the arylthio group, an arylthio group having 6 to 20 carbon atoms is preferable, and examples of the substituent include an alkyl group and an ionic hydrophilic group. Specific examples of the (substituted) arylthio group include a phenylthio group and a p-tolylthio group.

The heterocyclic group represented by R ² is preferably a 5-membered or 6-membered heterocyclic ring, and may be further condensed. As a hetero atom constituting the heterocyclic ring, a nitrogen atom, a sulfur atom and an oxygen atom are preferable. Moreover, it may be an aromatic heterocyclic ring or a non-aromatic heterocyclic ring, and the heterocyclic ring may further have a substituent. Preferred examples of the substituent here include the same substituents as those described above for the aryl group. Preferred heterocycles include 6-membered nitrogen-containing aromatic heterocycles, and 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. Specific examples of the (substituted) alkoxy group include a methoxy group, an ethoxy group, an isopropoxy group, a methoxyethoxy group, a hydroxyethoxy group, or a 3-carboxypropoxy group.

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 a phenoxy group, a p-methoxyphenoxy group, and an o-methoxyphenoxy group.

The acylamino group represented by R ⁸ includes an acylamino group having a substituent and an unsubstituted acylamino group. As the acylamino group, an acylamino group having 2 to 20 carbon atoms is preferable, and examples of the substituent include an ionic hydrophilic group. Specific examples of the (substituted) acylamino group include an acetamido group, a propionamido group, a benzamido group, or a 3,5-disulfobenzamido group.

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. Examples of the substituent include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, and an iso- group. A butyl group and a tert-butyl group are included. Specific examples include, in addition to the sulfonylamino group, for example, a methylsulfonylamino group and an ethylsulfonylamino group.

The alkoxycarbonylamino group represented by R ⁸ includes an alkoxycarbonylamino group having a substituent and an unsubstituted alkoxycarbonylamino group. As the alkoxycarbonylamino group, an alkoxycarbonylamino group having 2 to 20 carbon atoms is preferable, and examples of the substituent include an ionic hydrophilic group. A specific example of the (substituted) alkoxycarbonylamino group is preferably an ethoxycarbonylamino group.

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. Specific examples of the (substituted) ureido group include a 3-methylureido group, a 3,3-dimethylureido group, and a 3-phenylureido group.

The alkoxycarbonyl group represented by R ⁷ , R ⁸ , or 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. Specific examples of the (substituted) alkoxycarbonyl group include a methoxycarbonyl group and an ethoxycarbonyl group.

The carbamoyl group represented by R ² , R ⁷ , R ⁸ , or R ⁹ includes a carbamoyl group having a substituent and an unsubstituted carbamoyl group, and examples of the substituent include an alkyl group. Specific 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, and examples of the substituent include an alkyl group. Specific examples of the (substituted) sulfamoyl group include a dimethylsulfamoyl group and a di- (2-hydroxyethyl) sulfamoyl group.
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. Specific examples of the (substituted) acyl group include an acetyl group and a benzoyl group.

The ionic hydrophilic group represented by R ¹ , R ³ , R ⁵ , R ⁷ , R ⁸ , or R ⁹ includes a carboxyl group, a quaternary ammonium salt, a sulfonic acid group, and the like. Preferred examples include a carboxyl group and a sulfonic acid group.

In the substituted amino group represented by R ⁸ , examples of the substituent include an alkyl group, an aryl group, and a heterocyclic group. Specific examples of the substituted amino group include a methylamino group, a diethylamino group, and an anilino group. A group or 2-chloroanilino group is preferably exemplified.

The details of each of the substituents enumerated in each group represented by R ¹ , R ² , R ³ , R ⁵ , R ⁷ , R ⁸ or R ⁹ are the same as described above, and the preferred embodiments are also the same. It is.

In the general formulas (Y-II), (Y-III), and (Y-IV), the heterocyclic group represented by R ⁴ , R ⁶ , or R ¹⁰ is represented by the general formula (Y-I). It is synonymous with the optionally substituted heterocyclic group represented by B, and preferred examples, more preferred examples, and particularly preferred examples are also the same as 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 etc. are mentioned, These groups, such as an alkyl group and an aryl group, may have a substituent further.

  In addition, as an example of the substituent in the case where it may further have a substituent, the substituent which may be substituted on the heterocyclic rings A and B in the general formula (Y-I) can be exemplified.

In the general formula (Y-III), Za is -N =, - NH-, or -C (R ¹¹⁾ = represents, Zb and Zc each independently -N = or -C (R ¹¹⁾ = a To express. Here, R ¹¹ represents a hydrogen atom or a nonmetal substituent, and examples of the nonmetal substituent represented by R ¹¹ include a cyano group, a cycloalkyl group, an aralkyl group, an aryl group, an alkylthio group, an arylthio group, or an ion. A hydrophilic group is preferred. Each of these groups has the same meaning as each group in 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.

  Specific examples of the dye represented by the general formula (Y-I) include exemplified compounds Y-101 to Y-155 described in paragraph numbers [0139] to [0149] of JP-A-2003-073598. However, the present invention is not limited to these specific examples. These compounds can be synthesized with reference to JP-A-2-24191 and JP-A-2001-279145.

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

  Examples of cyan oil-soluble dyes include dyes represented by formulas (I) to (IV) of JP-A No. 2001-181547 and paragraph numbers [0063] to [0078] of JP-A No. 2002-121414. The dyes represented by the general formulas (IV-1) to (IV-4) are preferable, and specific examples include paragraph numbers [0052] to [0066] of JP-A No. 2001-181547 and JP-A No. 2002. And the compounds of paragraph Nos. [0079] to [0081] of No. 12214. Particularly preferred dyes are phthalocyanine dyes represented by the general formulas (CI) and (CII) 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 described in paragraphs [0198] to [0201] of JP-A No. 2002-121414. The oil-soluble dyes represented by formulas (I) to (IV), (IV-1) to (IV-4), (CI), and (C-II) are not only cyan but also black ink or You may use for inks of other colors, such as green ink.

  The oil-soluble dye described above is preferably present in a state of being dissolved in the fine particles when colored fine particles, and is preferably free from crystal precipitation over time. That is, it is important that the compatibility with the oil described above, that is, the polymer component described above (particularly, the hydrophobic portion thereof) is high.

  In the case of containing the water-insoluble dye, the amount of the water-insoluble dye (particularly oil-soluble dye) in the colored fine particles (for example, a fine particle dispersion when dispersed) is the amount of the colored fine particles (for example, the fine particle dispersion). ) 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.

<Pigment>
Next, the pigment will be described in detail. Suitable examples of the pigment include organic pigments. Examples of the organic pigment include a yellow pigment, an orange pigment, a red pigment, a violet pigment, a blue pigment, a green pigment, a brown pigment, and a black pigment.

  Examples of yellow pigments include C.I. I. Pigment yellow 20, C.I. I. Pigment yellow 24, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 86, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 109, C.I. I. Pigment yellow 110, C.I. I. Pigment yellow 117, C.I. I. Pigment yellow 125, C.I. I. Pigment yellow 137, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 139, C.I. I. Pigment yellow 185, C.I. I. Pigment yellow 147, C.I. I. Pigment yellow 148, C.I. I. Pigment yellow 153, C.I. I. Pigment yellow, C.I. I. Pigment yellow 154, C.I. I. Pigment yellow 166, C.I. I. Pigment yellow 168, C.I. I. Pigment yellow 185, and the like.

  Examples of orange pigments include C.I. I. Pigment orange 36, C.I. I. Pigment orange 43, C.I. I. Pigment orange 51, C.I. I. Pigment orange 55, C.I. I. Pigment orange 59, C.I. I. Pigment orange 61, C.I. I. Pigment orange 71, and the like.

  Examples of red pigments include C.I. I. Pigment red 9, C.I. I. Pigment red 97, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 149, C.I. I. Pigment red 168, C.I. I. Pigment Red 177, C.I. I. Pigment red 180, C.I. I. Pigment red 192, C.I. I. Pigment red 215, C.I. I. Pigment red 216, C.I. I. Pigment red 217, C.I. I. Pigment red 220, C.I. I. Pigment Red 223, C.I. I. Pigment red 224, C.I. I. Pigment red 226, C.I. I. Pigment red 227, C.I. I. Pigment red 228, C.I. I. Pigment red 240, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 209, C.I. I. Pigment red 146, C.I. I. Pigment red 11, C.I. I. Pigment red 81, C.I. I. Pigment red 123, C.I. I. Pigment red 213, C.I. I. Pigment red 272, C.I. I. Pigment red 270, C.I. I. Pigment red 255, C.I. I. Pigment red 264, C.I. I. Pigment red 254, and the like.

  Examples of violet pigments include C.I. I. Pigment violet 19, C.I. I. Pigment violet 23, C.I. I. Pigment violet 29, C.I. I. Pigment violet 30, C.I. I. Pigment violet 37, C.I. I. Pigment Violet 40, C.I. I. Pigment violet 50, and the like.

  Examples of the blue pigment include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 6, C.I. I. Pigment blue 22, C, I.I. Pigment blue 60, C.I. I. Pigment blue 64, and the like.

Examples of the green pigment include C.I. I. Pigment green 7, C.I. I. Pigment green 36, and the like.
Examples of the brown pigment include C.I. I. Pigment brown 23, C.I. I. Pigment brown 25, C.I. I. Pigment brown 26, and the like.
Examples of black pigments include C.I. I. Pigment black 7 and the like.

  When the pigment is contained, the amount of the pigment in the colored fine particles (for example, a fine particle dispersion when the dispersion is prepared) is based on the total mass (including the organic solvent) of the colored fine particles (for example, the fine particle dispersion). 0.05-20 mass% is preferable, 0.1-15 mass% is still more preferable, 0.2-10 mass% is especially preferable.

(Organic solvent)
The colored fine particles constituting the ink composition of the present invention can generally be constituted using an organic solvent. For example, when an ink composition is formed by dispersing colored fine particles in an aqueous medium, it can be prepared as an oil phase for an aqueous phase (aqueous medium) using an organic solvent together with the oil and the dye or pigment.

  The organic solvent is not particularly limited and is preferably selected based on the solubility of a water-insoluble dye (particularly an oil-soluble dye) or oil (particularly a polymer component constituting the organic solvent), for example, acetone, Ketone solvents such as methyl ethyl ketone and 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, benzene, toluene and the like Aromatic solvents, ester solvents such as ethyl acetate, butyl acetate and isopropyl acetate, ether solvents such as diethyl ether, tetrahydrofuran and dioxane, glycol ether solvents such as ethylene glycol monomethyl ether and ethylene glycol dimethyl ether, etc. It is.

Two or more organic solvents may be used in combination in addition to being used alone. Further, depending on the solubility of the dye, pigment or polymer component, it can be used as a mixed solvent with water.
The amount of the organic solvent used is not particularly limited as long as it does not impair the effects of the present invention, and is preferably 10 to 2000 parts by mass, and 100 to 1000 parts by mass with respect to 100 parts by mass of the oil described above. More preferred. If the amount used is less than 10 parts by mass, fine and stable dispersion of fine particles tends to be difficult, and if it exceeds 2000 parts by mass, the steps of solvent removal and concentration for removing the organic solvent become indispensable and complicated. In addition, there is a tendency that there is no room for blending design.

  When the vapor pressure of the organic solvent is larger than water, it is preferable to remove the organic solvent from the viewpoint of stability of the dispersion when dispersed and safety and health. As a method for removing the organic solvent, various known methods can be applied depending on the type of the solvent, and examples thereof include an evaporation method, a vacuum evaporation method, and an ultrafiltration method. The removal of the organic solvent is preferably carried out as soon as possible immediately after emulsification and dispersion when emulsified and dispersed.

  The content of the colored fine particles in the ink composition of the present invention is preferably 1 to 45% by mass and more preferably 2 to 30% by mass with respect to the mass of the composition. This content can be appropriately adjusted by dilution, evaporation, ultrafiltration and the like.

(Additive)
The colored fine particles according to the present invention may further contain an additive appropriately selected according to the purpose within a range not impairing the effects of the present invention. Examples of the additive herein include a neutralizing agent, a hydrophobic high-boiling organic solvent, a dispersant, and a dispersion stabilizer.

  When the polymer component constituting the oil has an unneutralized dissociable group, the neutralizing agent adjusts pH, self-emulsification, and imparts dispersion stability of the prepared colored fine particles (for example, colored fine particle dispersion). It can be suitably used for the purpose. 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 hydroxide). Potassium), carbonates (for example, sodium carbonate, sodium hydrogen carbonate, etc.), ammonia and the like.
The neutralizing agent is preferably added so as to have a pH of 4.5 to 10.0 from the viewpoint of improving dispersion stability in colored fine particles (for example, a colored fine particle dispersion), and has a pH of 6.0 to 10.0. It is more preferable to add so that it becomes.

Examples of the dispersant and the dispersion stabilizer include cationic, anionic, and nonionic surfactants, water-soluble or water-dispersible low molecular compounds, oligomers, and the like. The dispersant and / or dispersion stabilizer includes latex of the polymer component, the dye or pigment-containing liquid, the solution of the polymer component, the mixed solution of the polymer component and the dye or pigment, the oil and the dye or pigment. Although it may be added to any one of colored fine particles (for example, colored fine particle dispersion), a liquid containing at least water, etc., among others, latex of the polymer component and / or colored fine particles (for example, colored) It is preferable to add the dye or pigment-containing liquid prepared in the preceding step of the step of preparing the fine particle dispersion) or a liquid containing at least water.
The addition amount of the dispersant and the dispersion stabilizer is preferably 0 to 100% by mass, more preferably 0 to 20% by mass with respect to the total amount (mass) of the dye (particularly oil-soluble dye) or pigment and the polymer component. preferable.

  As the dispersant and dispersion stabilizer, nonionic surfactants are particularly preferable. For example, polyoxyethylene sorbitan fatty acid ester, sorbitan fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene derivative And oxyethylene / oxypropylene block copolymer. The amount used in the case of using the nonionic surfactant is 0.01 to 1.0 mass with respect to 1 part by mass of a dye (particularly an oil-soluble dye) or a pigment-containing liquid or a “liquid containing at least water”. Part is preferable, and 0.01 to 0.5 part by mass is preferable. In addition to the nonionic surfactant, an anionic surfactant may be used in an amount of 0.01 to 0.5 parts by mass with respect to 1 part by mass of a dye (particularly an oil-soluble dye) or pigment.

[Aqueous medium]
The aqueous medium according to the present invention includes water or a mixed solvent of water and a water-miscible organic solvent (for example, a small amount), and an additive or the like is further added to the water or the mixed solvent as necessary. Can also be used.
The proportion of the aqueous medium in the ink composition can be appropriately selected within a range that satisfies the above-described mass ratio of the colored fine particles.

  Additives to aqueous media include anti-drying agents, penetration enhancers, antioxidants, antifungal agents, pH regulators, surface tension regulators, antifoaming agents, viscosity modifiers, dispersants, dispersion stabilizers In addition, known additives such as a rust inhibitor and a chelating agent are included. For example, those described in paragraph numbers [0217] to [0226] of JP-A No. 2001-279141 can be appropriately selected and used.

[Other various additives]
In addition to the above components, the ink composition of the present invention includes a water-soluble organic solvent, a surface tension modifier, a viscosity modifier, a dispersant, a dispersion stabilizer, an antioxidant, an antifungal agent, and a rust inhibitor, as necessary. An appropriate amount of a pH adjuster, an antifoaming agent, a chelating agent, an ultraviolet absorber and the like can be used as appropriate additives. About these additives, what was described in Unexamined-Japanese-Patent No. 2001-181549 etc. can be selected suitably, and can be used.

The water-soluble organic solvent can be used for the purpose of a drying inhibitor or a penetration accelerator. As the water-soluble organic solvent, a water-soluble organic solvent having a vapor pressure lower than that of water is preferable. Specific examples include ethylene glycol, propylene glycol, diethylene glycol, polyethylene glycol, thiodiglycol, dithiodiglycol, 2-methyl-1,3-propanediol, 1,2,6-hexanetriol, glycerin, trimethylol. Substituted or unsubstituted polyhydric alcohols typified by propane, diethanolamine, etc., amyl alcohol, furfuryl alcohol, diacetone alcohol, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, triethylene glycol monoethyl ether, etc. Aliphatic monohydric alcohols, 2-pyrrolidone, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, heterocyclic rings such as N-ethylmorpholine, sulfora , 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, two or more types of water-soluble organic solvents may be used in combination in addition to a single type.

  The content of the water-soluble organic solvent in the ink composition is preferably 5 to 60% by mass, more preferably 7 to 50% by mass, and particularly preferably 10 to 40% by mass with respect to the total mass of the ink composition. preferable.

Examples of the surface tension adjusting agent include nonionic, cationic or anionic surfactants. Examples of the anionic surfactant include fatty acid salts, alkyl sulfate salts, alkylaryl sulfonates (eg, alkylbenzene sulfonates, petroleum sulfonates, etc.), dialkyl sulfosuccinates, alkyl phosphate ester salts, Naphthalene sulfonic acid formalin condensate, polyoxyethylene alkyl sulfate ester salt and the like, and as the nonionic surfactant, acetylene diol (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 ester, and an oxyethylene oxypropylene block copolymers.
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. The surfactants described in 308119 (1989) can also be used.

  Among the above, since the precipitation and separation from the ink composition hardly occur and the foaming property is small, the anionic surfactant having a hydrophobic part double-stranded or branched from the hydrophobic part, or the center of the hydrophobic part An anionic surfactant having a hydrophilic group in the vicinity thereof, a nonionic surfactant having a hydrophobic portion double-stranded or a hydrophobic portion branched (for example, one-terminal ester of polyethylene oxide of 2-butyloctanoic acid, Polyethylene oxide adducts of undecan-6-ol), 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.)) Further, among these, the molecular weight is 200 or more and 1000 or less. Is preferably a 900 more preferably less things than molecular weight 300, having a molecular weight of 400 or more 900 or less is particularly preferred.

  The surface tension when the ink composition of the present invention is prepared as a liquid composition is preferably in the range of 20 to 60 mN / m with or without the above-described surface tension adjusting agent. More preferably, it is 25-45 mN / m. Furthermore, the dynamic surface tension is preferably in the range of 20 to 40 mN / m with or without the surface tension adjusting agent. More preferably, it is 25-35 mN / m.

  The viscosity modifier can be used for the purpose of adjusting the viscosity when the ink composition of the present invention is prepared into a liquid composition. Examples of the viscosity modifier include water-soluble polymers such as celluloses and polyvinyl alcohol. In this case, the viscosity is preferably 30 mPa · s or less, and more preferably 20 mPa · s or less.

  Other additives such as dispersants, dispersion stabilizers, antioxidants, antifungal agents, rust inhibitors, pH adjusters, antifoaming agents, chelating agents, and ultraviolet absorbers other than those described above are disclosed in JP-A-2001-181549. The known compounds described in the above can be appropriately selected and used.

-Method of containing colored fine particles in aqueous medium-
Next, a method for containing colored fine particles in an aqueous medium will be described.
The colored fine particles according to the present invention have a water-insoluble dye or pigment and “the oxygen transmission coefficient at 25 ° C. is 2.60 × 10 ⁻¹³ [m ³ (STP) · m / (s · m ² · kPa)]. The ink composition of the present invention is most preferably produced by dispersing the colored fine particles in the form of fine particles in an aqueous medium (containing at least water). it can. Specifically, for example, (a) a method in which a latex (aqueous phase) of the polymer component is prepared in advance and an oil-soluble dye (oil phase) is impregnated therein, or (b) a co-emulsification dispersion method is used. Of these, the co-emulsification dispersion method is preferable. For the co-emulsification dispersion method, water (water phase) is added to a solution (oil phase) containing a polymer component and a dye (particularly oil-soluble dye) or pigment that constitutes an oil in an organic solvent, or water. A method in which the oil phase is emulsified and dispersed in water to form fine particles by adding the solution (oil phase) to the (water phase) is preferable.

  In the above, latex means a polymer in which the polymer component that is insoluble in the aqueous medium is dispersed as fine particles in the aqueous medium. The dispersion state may be that the polymer component is emulsified in an aqueous medium, emulsion-polymerized, micelle-dispersed, or the polymer component has a partially hydrophilic structure in the molecule and the molecular chain itself is Any of molecularly dispersed ones may be used.

Hereinafter, the method of containing the colored fine particles in the water-soluble medium will be described in detail using the above methods (a) and (b) as examples. First, (a) a method of preparing a latex of the polymer component in advance and impregnating it with an oily dye will be described.
The first example of the method (a) includes a first step of preparing a polymer latex (aqueous phase), and a first step of preparing a dye-containing liquid (oil phase) in which an oil-soluble dye is dispersed or dissolved in an organic solvent. A method comprising two steps and a third step of mixing and dispersing the polymer latex and the dye-containing liquid prepared in the first and second steps to prepare an ink composition which is a fine particle dispersion. is there.
The second example of the method (a) includes a first step of preparing a polymer latex (aqueous phase), and a dye-containing liquid (oil phase) in which an oil-soluble dye is dispersed or dissolved in an organic solvent, A second step of preparing a dye fine particle dispersion by mixing the dye-containing liquid and a liquid containing at least water, and mixing the polymer latex and the dye fine particle dispersion prepared in the first and second steps; And a third step of preparing an ink composition that is a fine particle dispersion.
As a third example of the method (a), the method described in JP-A-55-139471 can also be mentioned.

Next, (b) the co-emulsification dispersion method will be described.
The first example of the method (b) includes a first step of preparing a polymer / dye mixed solution (oil phase) in which an oil-soluble dye and a polymer component are dispersed or dissolved in an organic solvent; And a second step of preparing an ink composition, which is a fine particle dispersion, by mixing the polymer / dye mixed solution prepared in the above and a liquid (aqueous phase) containing at least water.
The second example of the method (b) is a first step of preparing a dye-containing liquid (oil phase) in which an oil-soluble dye is dispersed or dissolved in an organic solvent, and a polymer component is dispersed or dissolved in an organic solvent. The second step of preparing the polymer solution (oil phase), the dye-containing liquid prepared in the first and second steps, the polymer solution, and a liquid containing at least water (water phase) are mixed to disperse the fine particles. And a third step of preparing an ink composition as a product.
In the third example of the method (b), a dye-containing liquid (oil phase) in which an oil-soluble dye is dispersed or dissolved in an organic solvent is prepared, and the dye-containing liquid and a liquid (water phase) containing at least water are prepared. A first step of preparing a dye fine particle dispersion by mixing a polymer solution (oil phase) in which a polymer component is dispersed or dissolved in an organic solvent, and a liquid (water phase) containing this polymer solution and at least water An ink composition that is a fine particle dispersion by mixing the second step of preparing a polymer fine particle dispersion by mixing the dye fine particle dispersion and the polymer fine particle dispersion prepared in the first and second steps And a third step of preparing the product.
In the fourth example of the method (b), a dye-containing liquid (oil phase) in which an oil-soluble dye is dispersed or dissolved in an organic solvent is prepared, and the dye-containing liquid and a liquid (water phase) containing at least water are prepared. In a first step of preparing a dye fine particle dispersion, a second step of preparing a polymer solution (oil phase) in which a polymer component is dispersed or dissolved in an organic solvent, and the first and second steps. And a third step of preparing an ink composition as a fine particle dispersion by mixing the prepared dye fine particle dispersion and polymer solution.
The fifth example of the method (b) is a method comprising a step of directly preparing an ink composition that is a fine particle dispersion by mixing a liquid containing at least water with an oil-soluble dye and a polymer component. is there.

  The average particle diameter of the colored fine particles in the ink composition of the present invention 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 particle size distribution can be adjusted as desired by means such as centrifugation and filtration.

The ink composition of the present invention can be used in various fields. For example, it is suitable for uses such as ink for ink jet recording, water-based ink for writing, water-based printing ink, ink for information recording, etc., and can be particularly suitably used as ink for ink-jet recording (ink-jet recording ink). When used as ink for ink jet recording, the ink jet recording method is not particularly limited. For example, a charge control method for ejecting ink using electrostatic attraction force, a drop-on-demand method (pressure) using vibration pressure of a piezo element. Pulse type), acoustic ink jet method that converts electrical signal into acoustic beam, irradiates ink and uses ink to eject ink, thermal ink jet that heats ink to form bubbles and uses generated pressure Any of the method, etc. may be used. The inkjet recording method includes a method of ejecting a large number of low-density inks called photo inks in a small volume, a method of improving image quality using a plurality of inks having substantially the same hue and different concentrations, and colorless and transparent. A method using ink.
Among the above, it is suitable as an ink for ink jet recording such as a thermal type, a piezoelectric type, an electrolytic type, or an acoustic type.

  The ink for ink-jet recording is composed of the ink composition of the present invention described above, and can be configured to contain other additives appropriately selected as necessary, as described above. Additives here include anti-drying agents, penetration enhancers, antioxidants, antifungal agents, pH regulators, surface tension regulators, antifoaming agents, viscosity modifiers, dispersants, dispersion stabilizers, and rust inhibitors. And known additives such as chelating agents, and the details thereof are described in JP-A No. 2001-279141 (paragraph numbers [0217] to [0226]) in the same manner as the additive to the aqueous medium.

  The ink jet recording method of the present invention is to record an image on a recording material using the ink composition of the present invention described above, and the recording form can be any form that can use the ink composition of the present invention. It can be selected without particular limitation. For example, it can be suitably performed using a thermal type, piezoelectric type, electrolytic type, or acoustic type inkjet printer.

  When the ink composition of the present invention is used as an ink for a writing water-based ink, a water-based printing ink, an information recording ink, or the like, a recording material to be recorded using the ink composition is not particularly limited. The material can be appropriately selected, but paper material, resin material, or cloth material is suitable. Specifically, for example, plain paper, resin-coated paper, inkjet recording paper, plastic film, electrophotographic co-paper, Examples thereof include fabric, glass, metal, and ceramics. Of these, plain paper, resin-coated paper, inkjet recording paper, and plastic film are preferable, and inorganic fine particles described in paragraphs [0228] to [0246] of JP-A Nos. 2001-181549 and 2001-279141 are preferable. More preferably, a recording material having a porous ink-receiving layer containing the above (dedicated ink jet recording paper) or plain paper is used.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples. In the examples, ink for inkjet recording is prepared as an example of the ink composition, and “parts” and “%” in the examples are based on mass unless otherwise specified.

[Synthesis of polymer solution (oil)]
-Synthesis of polymer solution PA-01-
To a 200 ml three-diameter flask substituted with nitrogen gas, 22 parts of methyl ethyl ketone and 8.3 parts of 2-propanol were added and heated to 65 ° C., and then 0.17 part of azobisvaleronitrile (V-65) was added. Added further. This is followed by 35 parts of n-butyl acrylate (monomer), 15 parts of 2-hydroxyethyl acrylate (monomer), 0.42 parts of n-dodecanethiol, 22 parts of methyl ethyl ketone, and 8.3 parts of 2-propanol. Was added dropwise over 2 hours. Subsequently, after 2 hours of reaction, 0.088 parts of V-65 was added afterwards and the temperature was raised to 73 ° C. After a further 2 hours of reaction, an intended polymer solution PA-01 having a solid content concentration of 45% was synthesized.

(2) Synthesis of polymer solutions PA-02 to PA-11 Except that the two monomer components used in the synthesis of PA-01 obtained above were replaced with monomers 1 and 2 shown in Table 1 below, respectively. Polymer solutions PA-02 to PA-11 were synthesized by the same method as the synthesis of PA-01.

-Synthesis of polymer solution PR-01-
To a 200 ml three-diameter flask substituted with nitrogen gas, 22 parts of methyl ethyl ketone and 8.3 parts of 2-propanol were added, and the temperature was raised to 65 ° C. Then, 0.17 part of azobisvaleronitrile (V-65) was added. added. Next, 35 parts of n-butyl acrylate, 15 parts of M-90G (manufactured by Shin-Nakamura Chemical Co., Ltd.), 0.42 parts of n-dodecanethiol, 22 parts of methyl ethyl ketone, and 8.3 parts of 2-propanol The mixed solution was added dropwise over 2 hours. Subsequently, after 2 hours of reaction, 0.088 parts of V-65 was added afterwards and the temperature was raised to 73 ° C. After a further 2 hours of reaction, an intended polymer solution PR-01 having a solid content concentration of 56% was synthesized.

-Synthesis of polymer solution PR-02-
To a 200 ml three-diameter flask substituted with nitrogen gas, 22 parts of methyl ethyl ketone and 8.3 parts of 2-propanol were added, and the temperature was raised to 65 ° C. Then, 0.17 part of azobisvaleronitrile (V-65) was added. added. Next, a mixed solution of 50 parts of n-butyl acrylate, 0.42 part of n-dodecanethiol, 22 parts of methyl ethyl ketone, and 8.3 parts of 2-propanol was added dropwise thereto over 2 hours. Subsequently, after 2 hours of reaction, 0.088 parts of V-65 was added afterwards and the temperature was raised to 73 ° C. After a further 2 hours of reaction, an intended polymer solution PR-02 having a solid content concentration of 60% was synthesized.

About each of the polymer solution synthesize | combined from the above, the glass transition temperature (Tg) and the oxygen permeability coefficient were measured as follows. The measurement results are shown in Table 2 below.
(1) Measurement of glass transition temperature 5.0 mg of each polymer solution was used as a polymer sample for measurement, and the glass transition temperature (Tg) of the polymer component in the polymer solution was measured using a differential scanning calorimeter DSC (DSC-6200R, Seiko Instruments ( Measured in a temperature range of -100 ° C to 150 ° C.
(2) Measurement of oxygen permeability coefficient Oxygen analyzer (model 3600 [diaphragm 2956A 25 μm], manufactured by Orbis Fair Laboratories Japan Inc.), each polymer solution was uniformly coated on the detection head under the conditions of 25 ° C. and humidity of 50 RH%. The oxygen permeability coefficient [unit: m ³ (STP) · m / (s · m ² · kPa)] was calculated by calibrating the oxygen concentration detected by the electrode using a standard permeation sample.

Example 1
[Preparation of Colored Fine Particle Dispersion DA-01]
A mixed solution of 16 parts of ethyl acetate, 2.7 parts of the polymer solution PA-01 (prepared to a solid content concentration of 50%; oil) obtained from the above, and 0.45 part of the following oil-soluble dye (M-1) Prepared. Separately, a mixed solution of 18 parts of water and 0.4 part of Emar 20C (manufactured by Kao Corporation) was prepared. Then, the obtained two mixed solutions were mixed and emulsified and mixed using a homogenizer (manufactured by Nippon Seiki Co., Ltd.). Next, the emulsion was concentrated at 30 ° C. under reduced pressure to remove ethyl acetate, and a colored fine particle dispersion DA-01 having a solid content concentration of 17% was prepared. It was 78 nm when the volume average particle diameter of this colored fine particle dispersion was measured with LB-500 (made by HORIBA Co., Ltd.).

[Preparation of Ink for Inkjet Recording IA-01]
The following composition was mixed and filtered using a 0.45 μm filter to prepare an aqueous inkjet recording ink IA-01 according to the present invention which is a fine particle dispersion.
〔composition〕
-Colored fine particle dispersion DA-01 ... 50 parts-Diethylene glycol ... 5 parts-Glycerin ... 18 parts-Triethanolamine ... 1 part-Orphine E1010 ... 1 part-Water ... Amount to be 100 parts in total

(Examples 2 to 11)
In Example 1, the polymer solution PA-01 was replaced with any of the polymer solutions PA-02 to PA-11 obtained as described above as shown in Table 2 below, and a colored fine particle dispersion (DA-02 to DA-11) was used. In the same manner as in Example 1, except that DA-02 to DA-11 were used in place of DA-01, the water-based inkjet recording inks IA-02 to IA-11 of the present invention were used. Produced.

(Comparative Examples 1-2)
In Example 1, a colored fine particle dispersion (DR-01 or DR-02) was prepared by replacing the polymer solution PA-01 with the polymer solution PR-01 or PR-02 obtained above as shown in Table 2 below. Then, comparative water-based inkjet recording inks IR-01 to IR-02 were prepared in the same manner as in Example 1 except that DR-01 or DR-02 was used instead of DA-01.

(Comparative Examples 3-4)
As a comparative water-based ink, magenta ink (manufactured by Seiko Epson Co., Ltd .; hereinafter referred to as “ink-jet recording ink IR-03”) dedicated to the inkjet printer PM-950C is used as a comparative pigment ink. A magenta ink dedicated to PMV-600 (manufactured by Seiko Epson Corporation; hereinafter referred to as “ink-jet recording ink IR-04”) was prepared.

[Image recording and evaluation]
The ink jet recording inks IA-01 to IA-11 of the present invention obtained as described above and the ink jet recording inks IR-01 to IR-04 for comparison are cartridges of an ink jet printer PMV-600 (manufactured by Seiko Epson Corporation). The image was recorded on PPC plain paper and photographic image quality paper (manufactured by Seiko Epson Corporation) using the same machine, and the following evaluation was performed. The evaluation results are shown in Table 2 below.

1. Evaluation of paper dependence The color tone of an image recorded on photographic quality paper and the image recorded on plain paper for PPC are compared, and A is the case where there is almost no color tone difference between the two images. Three-stage evaluation was performed with B as the case where the difference was small and C as the case where the color difference between the two images was large.

2. Glossiness evaluation Gloss unevenness of images recorded on photographic image quality paper is visually evaluated, A with no gloss unevenness is A, B with slight gloss unevenness is B, and gloss unevenness is clearly recognized A three-stage evaluation was performed with C as the value. The gloss unevenness becomes prominent when the penetration into the paper is insufficient, and serves as an index for evaluating the penetration (ink permeability).

3. Evaluation of water resistance The image-recorded photographic quality paper was dried at room temperature for 1 hour, then immersed in water for 30 seconds, and observed again when it was naturally dried at room temperature. A three-stage evaluation was performed, where B was slightly recognized as B and C was desired as a large amount of bleeding.

4). Evaluation of light resistance After measuring the density (D ¹ ) of each image in advance using a reflection densitometer (X-Rite 310TR, manufactured by X-Rite Co., Ltd.) Photographic paper was irradiated with xenon light (100,000 lux) for 3 days using a weather meter (Atlas C.165), and the image density (D ² ) after irradiation was measured in the same manner as described above. The dye residual ratio (%; D ² / D ¹ × 100) was determined from the measured concentrations D ¹ and D ² and used as an index for evaluating light resistance. The reflection density D ¹ before irradiation was measured by fixing to 1.0. The evaluation was performed in a three-stage evaluation, with A as the case where the dye residual ratio was 80% or more, B as the case where it was less than 80%, and C as the case where it was less than 70%.

5. Evaluation of ozone resistance For each of the image-recorded photographic quality papers, the density (D ³ ) of each image was previously measured using a reflection densitometer (X-Rite 310TR, manufactured by X-Rite), Photographic quality paper was stored for 3 days under the condition of ozone concentration 0.5 ppm, and the image density (D ⁴ ) after storage was measured in the same manner as described above. A dye residual ratio (%; D ⁴ / D ³ × 100) was determined from the measured concentrations D ³ and D ⁴ and used as an index for evaluating ozone resistance. The evaluation was performed in a three-stage evaluation, with A as the case where the dye residual ratio was 80% or more, B as the case where it was less than 80%, and C as the case where it was less than 70%.

6). Scratch resistance evaluation An image that had been aged for 30 minutes after image recording was visually evaluated for the presence or absence of changes in the density of the image by rubbing with an eraser. A three-stage evaluation was performed with B as the material and C as the material where the change was greatly confirmed.

  As shown in Table 2 above, the ink jet recording ink of the present invention has not only excellent ink permeability but also excellent weather resistance, water resistance, and scratch resistance compared to the comparative ink jet recording ink. There was no paper dependency, and high-density and high-quality image recording could be stably performed without clogging at the discharge nozzle portion. Further, the gloss when recording an image on photographic quality paper was also excellent.

Claims (7)

At least an aqueous medium, an oil having an oxygen permeability coefficient at 25 ° C. of 2.60 × 10 ⁻¹³ [m ³ (STP) · m / (s · m ² · kPa)] or less, and a water-insoluble dye Alternatively, an ink composition comprising colored fine particles containing a pigment.   The ink composition according to claim 1, wherein the oil has a softening start temperature of 25 ° C. or lower.   The ink composition according to claim 1, wherein the oil comprises a polymer component.   The ink composition according to claim 3, wherein the polymer component has a glass transition temperature of 25 ° C. or lower.   The ink composition according to any one of claims 1 to 4, which is used for inkjet recording.   An ink jet recording method comprising: recording an image on a recording material using the ink composition according to claim 1.   The inkjet recording method according to claim 6, wherein the recording material is a paper material, a resin material, or a cloth material.