JP2003213182A - Aqueous colored fine particle dispersion, aqueous ink, and image formation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prepare an aqueous colored fine particle dispersion which has an excellent dispersion stability and is used for an aqueous inkjet ink having a good storability and a high delivery stability; and to provide an image formation method using an inkjet method with a high print density and an excellent light resistance. <P>SOLUTION: The aqueous colored fine particle dispersion is characterized in that it contains a resin and at least two colorants incorporated in the resin. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous dispersion of colored fine particles for an inkjet ink, an aqueous ink, which has excellent storage stability, good ejection stability, and excellent image fastness, and an image forming method.

[0002]

2. Description of the Related Art In recent years, solvent-free and water-based recording materials and inking materials used in printers, printing machines, markers, writing instruments and the like have been required. In particular, as an aqueous recording material used for ink jet recording, a material mainly composed of an aqueous solution of a water-soluble dye and a material mainly composed of a fine dispersion of a pigment are widely used.

Aqueous inks using water-soluble dyes are mainly aqueous dyes of water-soluble dyes classified into acid dyes, direct dyes, some food dyes, etc., and glycols, alkanolamines, surface tension as moisturizers. A surfactant for adjusting the above is added, and if necessary, a thickener and the like are added. Water-based inks using these water-soluble dyes are most commonly used because of their high reliability against clogging at the tip of a brush or printer, but they are easily bleeding on recording paper, their use is limited, and their recording quality is degraded. Are forced to. In other words, it is difficult to say that a water-soluble dye that has simply penetrated into a recording paper and that has been dry-fixed is "dyed", and the light fastness is very low.

Further, in order to solve the problem that the water-based ink using a water-soluble dye has low water resistance and light fastness, a proposal for coloring a water-dispersible resin with an oil-soluble dye or a hydrophobic dye is disclosed in, for example, Japanese Patent Application Laid-Open No. 55-139471, JP-A-5
No. 8-45272, JP-A-3-250069, JP-A-8-253720, JP-A-8-92513, JP-A-8-183920, and JP-A-2001-11347.

Further, not only the water-dispersible resin is colored with an oil-soluble dye or a hydrophobic dye, but also colored fine particles made of a coloring material and a resin coating the coloring material, or coloring material particles made of a coloring material and a resin are further added. Attempts have also been made to use colored fine particles coated with a film-forming resin.

On the other hand, even in a pigment ink mainly composed of a fine dispersion of pigments, in order to reduce problems such as lack of density and easy occurrence of color reproducibility problems such as bronzing, For the purpose of improving light resistance, dispersion stability, ejection stability, and the like, for example, JP-A-8-26937.
4, JP-A-9-151342, and JP-A-10-880.
As disclosed in Japanese Patent No. 45, JP-A-10-292143, etc., attempts have been made to coat the surface of the pigment with a film-forming resin.

However, particles obtained by coloring a water-dispersible resin with these oil-soluble dyes or hydrophobic dyes, particles obtained by mixing fine particles of a coloring material such as a pigment with a resin, or colored fine particles obtained by further coating these particles with a resin. When making
In many cases, it is not possible to stably produce a fine particle dispersion containing a high-concentration coloring material due to insufficient solubility or affinity for coloring materials such as dyes and pigments and organic solvents to the organic solvent. Also, because the dye is easily deposited, the pigment and the resin are difficult to mix, and the coloring material such as the dye or the pigment is present on the particle surface (not completely covered with the resin), the colored fine particles are The dispersion stability of itself is impaired, and the dispersion stability required for inkjet inks,
There are problems that it is difficult to improve various performances such as ejection stability, and the effects of improving light resistance are reduced.

[0008]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a colored fine particle water dispersion for use in a water-based inkjet ink having excellent dispersion stability, good storage stability, and high ejection stability. An object of the present invention is to provide an image forming method using an inkjet method, which has high printing density and excellent light resistance.

[0009]

The above objects of the present invention can be achieved by the following means.

1. A colored fine particle water dispersion containing a coloring material and a resin, wherein two or more kinds of coloring materials are simultaneously contained in the resin.

2. 2. The colored fine particle water dispersion as described in 1 above, which contains only a dye as a coloring material.

3. 2. The colored fine particle water dispersion as described in 1 above, which contains both a dye and a pigment as a coloring material.

4. 2. The colored fine particle water dispersion as described in 1 above, which contains only a pigment as a coloring material.

5. The difference in SP value between color materials is 4.0 (Jo
ule / cm ³ ) ^{1/2 or} less, 1 above
Water dispersion of colored fine particles of.

6. 6. An aqueous dispersion of colored fine particles, wherein the colored fine particles in the aqueous dispersion of colored fine particles according to any one of 1 to 5 above are coated with a polymer shell to form a core / shell structure.

7. 7. The colored fine particle water dispersion according to any one of 1 to 6 above, wherein the resin contains polyvinyl butyral.

8. 8. The colored fine particle water dispersion according to any one of 1 to 7 above, wherein the colored fine particles have an average particle diameter of 100 nm or less.

9. 9. An aqueous ink comprising the colored fine particle water dispersion according to any one of 1 to 8 above.

10. 10. The water-based ink as described in 9 above, which is an inkjet ink.

11. 11. An image forming method, wherein the ink described in 10 above is ejected as droplets from an inkjet head based on a digital signal and attached to an ink receiving medium.

In a multicolor ink jet ink set in which inks of 12.2 or more different colors are combined, at least one kind of ink has an SP value difference of 4.0.
An ink set comprising a colored fine particle water dispersion prepared by mixing a plurality of dyes having a ratio of (Joule / cm ³ ) ^{1/2 or} less.

The present invention will be described in detail below. When producing colored fine particles containing coloring materials such as resin and dye, high concentration due to insufficient solubility of dye and resin in organic solvent or insufficient affinity of dye for resin when forming fine particles In many cases, colored fine particles containing the above dye cannot be stably produced. For example, in the case of a dye, the dye tends to separate from the organic solvent even if dissolved, or the dye tends to separate and precipitate from the resin even after forming fine particles, which causes a problem such as impairing the stability of the colored fine particle dispersion. cause. The present inventors have found that by dissolving different kinds of dyes at the same time and mixing this with a resin, the dissolution stability is increased and the dispersion stability is increased.

Even when a pigment is used as a coloring material, if the pigment has a low affinity for the organic solvent or the resin, the pigments tend to aggregate with each other and are unlikely to mix with different molecules such as the resin, so that they are often mixed with the resin. The state of mixing is non-uniform, the coating with the resin is insufficient, and it is difficult to produce colored particles that are stable in dispersion, fall off from the resin component, agglomerate among the particles due to undesired interaction between the pigments, and so on.
The present inventors, by mixing different pigments,
It was found that a stable dispersion can be produced by suppressing the cohesive force and increasing the compatibility with the resin. It is also preferable in terms of color tone.

When two or more kinds of coloring materials are mixed not only with dyes or pigments but also with dyes and pigments at the same time with the resin, the dyes are easily molecularly dispersed in the resin and interact with the surfaces of the pigment particles. Since the action is performed in a molecular unit, it is preferable to use the dye and the dye together with the resin when the pigment is contained in the resin, because the resin can more sufficiently coat the pigment.

Therefore, according to the present invention, by mixing two or more kinds of coloring materials in the resin at the same time, the compatibility between the coloring material and the resin in the obtained colored fine particles is improved, and the coloring material is mixed in the resin. Since the amount of color material to be melted can be increased and the color material density can be set high as a result, high printing density can be obtained. Further, since the aggregation of the coloring materials is suppressed and the dispersibility of the coloring materials in the resin is improved, thereby enhancing the effect of coating the coloring materials with the resin, a stable colored fine particle dispersion can be obtained.

However, in the present invention, when two or more kinds of coloring materials are mixed, it is preferable that all of the two or more kinds of coloring materials are dyes, and the dyes easily interact with each other between molecules, and the dye concentration in the resin is high. Easy to increase,
Further, since a uniform distribution is easily formed in the resin, it is possible to obtain a high-concentration ink which is excellent in covering property with the resin, has good stability as a dispersion, and is excellent in ejection stability. or,
It is also preferable because the fastness of the dyestuff is improved by the resin.

The coloring material contained in the colored fine particle water dispersion containing the coloring material and the resin in the present invention is as follows.
It is preferable that the coloring materials are not the same kind but different kinds of coloring materials and have a certain degree of interaction.

Since a certain degree of interaction is required, the effect of the present invention is small if one color material is very little in another color material. At least 10% by mass of another coloring material needs to be contained in another coloring material, preferably 20%.

As described above, in order to improve the compatibility with the resin and the concentration of the coloring material by interacting with each other, the solubility parameter (S
It is preferable to select color materials having P) values within 4.0 (Joule / cm ³ ) ^1/2 .

The solubility parameter is a child which is often used in evaluating the solubility of a non-electrolyte in an organic solvent.
It is a value obtained by the solubility parameter of ebrand. For this solubility parameter, see J. H. Child
ebrand, J .; M. Prausnitz. R. L.
"Regular and Relate" by Scott
d Solutions ”, Van Nostrand
-Reinhold, Princeton (1970
), "Polymer Data Handbook Basic Edition", Polymer Society of Japan. The values of the solubility parameters of various solvents are A. F.
M. Barton, “Handbook of Sol
rbility Parameters and Oth
er Cohesion Parameters ”, C
RC Press, Boca Raton / Flori
da (1983), "Polymer Data Handbook: Basic Edition", Polymer Society of Japan.

The solubility parameter of a substance is defined by SP = (δE / V) ^1/2 , where δE is the cohesive energy per mole and V is the molar volume.

The solubility parameter can be determined by several methods such as a method of determining from solubility, or a latent heat of vaporization method, a vapor pressure method, a swelling method, a surface tension method, a thermal swelling coefficient method, and a refractive index method.

In the present invention, any solubility parameter obtained by the following method is used.
In addition, the unit is (Joule / cm
³ ) It shall be represented by ^1/2 .

The solubility parameter can be obtained from the solubility in various solvents having known SP values. The method of determining the solubility parameter by the solubility in this solvent is
This is effective when the structure of the dye or the like is unknown.

In the dye of the present invention, for example, ethanol, acetone, methyl ethyl ketone, ethyl acetate, etc.
Using various solvents having known SP values, a dissolution method is used in which the SP value of the dye as a solute is obtained from the SP value of the solvent having the highest solubility. In this method, δd (dispersion force term), δp (polarity term), and δh (hydrogen bond term), which are each component of the SP value of each solvent of the group having the highest solubility, are plotted separately for each term, The central value is calculated for each term.
The SP value of the dye can be obtained by using the center value as the value of each term of the SP value of the dye. C. M. Ha
nsen, J .; Paint Technology. , 39
(505) 104 (1967), C.I. M. Hanse
n, J. Paint Technology. , 39 (51
1) 505 (1967) It is difficult to accurately determine the SP value by a dissolution method with a pigment having a low solvent solubility, but the above-mentioned document shows a measurement using a suspension state. That is, the closer the solvent is to the pigment, the better the wetting of the pigment. Therefore, after mixing the solvent and the pigment, shake the solvent well to produce a solvent in a good suspended state (not settling) such as ethanol, acetone, methyl ethyl ketone, ethyl acetate, etc. (A plurality of solvents may be used), and δd (dispersion force term), δp (polarity term), and δh (hydrogen bond term) of each solvent in good suspension state are divided for each term. Plot each δd (dispersion force term), δp (polarity term), δh
The SP value of the pigment can be determined by calculating the center value of each (hydrogen bond term) term and using the calculated center value of each term as each term of the SP value of the pigment to be determined.

The solubility parameter can be calculated by calculation when the structure is known. Small proposed a method of calculating the SP value by relating the chemical composition to the SP value and dividing the sum of the molar attraction constants ΔF in the molecule by the molar volume V. In this method, ΔF can be assigned to each atomic group, so that it can be easily calculated.

S = (ΣΔF) / V However, in the Small equation, since only the cohesive energy generated from the dispersive force is included, in order to further improve the accuracy of the above calculation method, Rheineck, Hoy, Kre
velen, Fedors and others have proposed different modified ΔF. In addition, Hansen proposed three-dimensionally decomposed parameters. Although the numerical value varies slightly depending on each correction parameter, the error when viewed as the difference between the two types of color materials defined in the present invention is small. When the structure is known, the solubility parameter obtained by calculation using the above-mentioned correction parameter can be used. The calculation program used in the present invention is Project Leader in a molecular calculation package called CACHE manufactured by Fujitsu Limited.

The solubility parameter calculated by any of these methods is used in the present invention. When the solubility parameter value is obtained from the solubility in a solvent, for example, the solubility parameter value of the solvent to be used may be slightly different depending on the obtaining method, and the SP value of the coloring material is slightly different accordingly. . However, since the difference in the value is not so large, the difference in SP value between the color materials may be the smallest.

Therefore, in the case of a dye or pigment having a known structure, it is preferable to use the above-mentioned calculation method. If the difference between the solubility parameters of two or more coloring materials obtained in this way is within 4.0 (Joule / cm ³ ) ^1/2 , the coloring materials have an appropriate affinity, and It is preferable because the affinity with the resin does not decrease due to the strength of the cohesive force between the molecules as in the case of one kind of coloring material, and the compatibility with the resin is improved.

The resin (polymer) used in the present invention will be described. The resin (polymer) used in the present invention has a number average molecular weight of 500 to 1
It is preferably from 0,000, and particularly from 1,000 to 30,000, from the viewpoints of film-forming property after printing, its durability, and suspension formability.

Various Tg can be used as the Tg of the polymer, but at least 1 is selected from the polymers used.
As the seed or more, it is preferable to use one having Tg of 10 ° C. or more.

In the present invention, generally known resins (polymers) can be used, but preferred (polymer) polymers are polymers containing an acetal group as a main functional group, polymers containing a carbonic acid ester group. , A polymer having a hydroxyl group and a polymer having an ester group, and particularly a polymer having an acetal group, of which polyvinyl butyral is preferable.

The above-mentioned polymer may have a substituent, and the substituent may have a linear, branched or cyclic structure. Various polymers having the above-mentioned functional group are commercially available, but they can be synthesized by a conventional method. In addition, these copolymers have, for example, an epoxy group introduced into one polymer molecule,
It can also be obtained by subjecting the polymer to polycondensation with another polymer later or performing graft polymerization with light or radiation.

Further, a polymer obtained by radical polymerization of a vinyl monomer having a polymerizable ethylenically unsaturated double bond is also preferably used. Polymers obtained by radical polymerization of ethylene, propylene, butadiene, vinyl chloride, vinylidene chloride, vinyl acetate, styrene, (meth) acrylic acid esters, (meth) acrylic acid, acrylamides, for example, styrene / ethyl acrylate Examples thereof include copolymer polymers such as butyl acrylate, copolymer polymers such as styrene / ethylhexyl methacrylate, and copolymer polymers such as styrene / ethylhexyl methacrylate / hydroxyethyl acrylate. .

In the present invention, a particularly preferable polymer is a polymer containing an acetal group (polyvinyl acetal). Among them, polyvinyl butyral is particularly preferable in terms of interaction such as solubility and affinity with coloring materials such as dyes and pigments. Preferably, when a plurality of resins are used in the present invention, one of them is preferably polyvinyl butyral, and in addition to these, one or more of the above polymers are mixed and used as a resin component different from polyvinyl butyral. It is preferable.

The colored fine particle water dispersion of the present invention comprises the above-mentioned resin (a plurality of which may be used) and a dye (or pigment).
And (2) are dissolved (or dispersed) in an organic solvent, emulsified in water and then removed by a method of removing the organic solvent. Alternatively, for example, a method of previously forming a resin fine particle water dispersion by emulsion polymerization, mixing the resin fine particle water dispersion with an organic solvent solution in which a dye is dissolved, and then impregnating the resin fine particles with the dye, etc. , Can be obtained by various methods.

An aqueous ink dispersion of such colored fine particles can be used to form an ink jet ink.
Preventing aggregation of the colored fine particle dispersion over a long period of time,
In order to improve the stability of the fine particles as an ink suspension and to impart fastness to the image such as the color tone and gloss of the image when printed on a medium, and further the light fastness, the colored fine particles are used as a core and further from an organic polymer. It is preferable to form a shell consisting of

As a method of forming the shell, there is a method of gradually dropping a polymer dissolved in an organic solvent and adsorbing it onto the surface of the colored fine particle core at the same time as precipitation. In the present invention, a coloring material and two kinds are used. After forming the colored fine particles to be the core containing the above resin, in the presence of an activator by adding a monomer having a polymerizable unsaturated double bond, emulsion polymerization is carried out, the shell is deposited on the core surface at the same time as the polymerization. The method of forming is preferred. Even when formed by this method,
For example, when a dye is used as a coloring material, there is some phase mixing at the core / shell interface and the coloring material content in the shell does not necessarily become zero, but less mixing is preferable. , Coloring material content (concentration) in shell
Is preferably 0.8 or less, more preferably 0.5 or less, of the coloring material content (concentration) in the core which is not core / shelled.

Examples of the monomer having a polymerizable unsaturated double bond forming a polymer that coats the colorant particles as a shell include ethylene, propylene, butadiene, vinyl chloride, vinylidene chloride, vinyl acetate, styrene, and (meth).
Acrylic esters, (meth) acrylic acid, etc., compounds selected from acrylamides, special styrene, ethyl (meth) acrylate, butyl (meth) acrylate,
(Meth) acrylic acid esters such as ethylhexyl (meth) acrylate are preferable, but in addition to these monomers, a polymerizable unsaturated monomer having a hydroxyl group in the molecule, for example, hydroxyethyl (meth) acrylate, etc. It is preferable to use such an ester such as hydroxyalkyl (meth) acrylate as a mixture with up to 50% of the total raw material monomers forming the shell, and another monomer having an ethylenically unsaturated double bond. In addition, for reasons such as increasing the stability of the shell, a monomer containing a carboxylic acid such as acrylic acid or methacrylic acid or a monomer containing a sulfonic acid, such as an ethylenic group containing a dissociative group having a pKa value of 3 to 7 is used. The unsaturated monomer may be used in an amount of 10% or less, which is smaller than the amount of the monomer containing the hydroxyl group. By using a monomer component containing these hydroxyl groups for shell formation, the core /
The stability of the aqueous dispersion of shell-colored fine particles is remarkably improved.

(Evaluation of core shell formation) It is important to evaluate whether the core shell is actually formed. In the present invention, the particle size of each particle is as very small as 200 nm or less, so the analysis method is limited from the viewpoint of resolution. TEM and TOF are used as analysis methods that meet such purposes.
-SIMS etc. can be applied. When observing the core-shelled fine particles by TEM, the dispersion can be applied and dried on the carbon support film and observed. In the TEM observation image, the contrast difference may be small only with the type of polymer that is an organic substance. Therefore, in order to evaluate whether or not it is core-shelled, the fine particles were osmium tetraoxide, ruthenium tetraoxide, chlorosulfonic acid / It is preferable to dye with uranyl acetate, silver sulfide or the like. Fine particles of only the core are dyed and observed by TEM, and compared with those having a shell. Further, after mixing the fine particles provided with the shell and the fine particles not provided with the shell, it is dyed, and it is confirmed whether or not the proportion of the fine particles having different dyeing degrees matches the presence or absence of the shell.

In a mass spectrometer such as TOF-SIMS, by providing a shell on the surface of particles, it is confirmed that the amount of coloring material near the surface is smaller than when only the core is used. When the coloring material has an element that is not contained in the polymer of the core shell, it is possible to confirm whether or not a shell having a small coloring material content is provided by using the element as a probe.

In the absence of such elements, the colorant content in the shell can be compared with that without the shell using a suitable dye. For example, core-shell formation can be observed more clearly by embedding core-shell particles in an epoxy resin, making an ultrathin section with a microtome, and staining. As described above, when the polymer or the coloring material has an element that can be a probe, TOF-SIMS or TEM
It is also possible to estimate the composition of the core-shell and the amount of color material distributed to the core and the shell.

In order to obtain the required particle size in the colored fine particles of the present invention, it is important to optimize the formulation and select an appropriate emulsification method. The formulation depends on the coloring material and polymer used, but since it is a suspension in water, it is generally necessary that the polymer forming the shell has a higher hydrophilicity than the polymer forming the core. Further, the coloring material contained in the polymer constituting the shell is preferably less than that in the polymer constituting the core as described above, and the coloring material also needs to be less hydrophilic than the polymer constituting the shell. . Hydrophilicity and hydrophobicity can be estimated using the above-mentioned solubility parameter (SP), for example.

In the present invention, the coloring material-containing core / shell colored fine particles used in the polymer emulsion type water-based ink have a very large surface area per unit volume when the volume average particle diameter is 5 nm or less. The effect of encapsulation in the polymer is reduced. On the other hand, 20
If the particles are larger than 0 nm, the head is likely to be clogged, sedimentation in the ink is likely to occur, and the stagnation stability is deteriorated. Therefore, the average particle size of the colored fine particles is 5 to 200.
The average particle size is preferably 10 nm to 150 nm, and when the average particle size exceeds 150 nm, the glossiness of the image recorded on the glossy media deteriorates when the ink is aqueous ink, and the image recorded on the transparency medium is deteriorated. In that case, a marked deterioration in transparency occurs. Further, if the average particle size of the colored fine particles is less than 10 nm, the stability of the colored fine particles tends to deteriorate, and the storage stability of the ink tends to deteriorate. Most preferred is 10-100 nm.

The volume average particle diameter is measured by a transmission electron microscope (T
EM) The circle-converted average particle diameter obtained from the average value of the projected area of the photograph (obtained for at least 100 particles or more)
Calculated as spherical equivalent. The coefficient of variation can be obtained by obtaining the volume average particle diameter and its standard deviation and dividing the standard deviation by the volume average particle diameter. Alternatively, the coefficient of variation can be obtained by using the dynamic light scattering method. For example, it can be determined using a laser particle size analysis system manufactured by Otsuka Electronics or a Zetasizer manufactured by Malvern Instruments.

The coefficient of variation of the particle size is a value obtained by dividing the standard deviation of the particle size by the particle size. The larger this value is, the wider the distribution of the particle size is. When the coefficient of variation of the volume average particle size is 80% or more, the particle size distribution becomes very wide, the thickness of the core shell is likely to be non-uniform, and the surface properties among particles are likely to vary. Variations in surface properties tend to cause aggregation of particles and easily cause clogging of the inkjet head. In addition, the aggregation of particles easily causes light scattering of the coloring material on the medium, and thus easily deteriorates the image quality. The coefficient of variation is preferably 50% or less, more preferably 30% or less.

In the present invention, the amount of polymer used for the shell is preferably 5% by mass or more and 95% by mass or less of the total amount of polymer. When the amount is less than 5% by mass, the thickness of the shell is insufficient and a part of the core containing a large amount of coloring material is likely to appear on the particle surface. If the shell polymer is too large, the ability of the core to protect the coloring material is likely to deteriorate. More preferably, it is 10% by mass or more and 90% by mass or less.

The total amount of coloring materials such as dyes and pigments is preferably 20% by mass or more and 1,000% by mass or less based on the total amount of polymer. If the amount of the color material is too small compared to the polymer, the image density after ejection will not increase, and if the amount of the color material is too large, the protective ability of the polymer will not be sufficiently obtained.

In the present invention, a colored fine particle water dispersion in which two or more kinds of coloring materials are simultaneously contained in the resin is prepared, and two or more different coloring materials can be selected from the following coloring materials and used. Good. Particularly, it is particularly preferable to select two or more kinds in which the difference in the solubility parameter (SP) value between the color materials is within 4.0 (Joule / cm ³ ) ^1/2 .

The coloring material encapsulated by the polymer will be described. As the hue of the coloring material used in the present invention, yellow, magenta, cyan, black, blue, green and red are preferably used, and yellow, magenta, cyan and black dyes are particularly preferable. Oil-soluble dyes are usually water-insoluble dyes that are soluble in organic solvents that do not have water-soluble groups such as carboxylic acids and sulfonic acids, but are soluble in oil by forming a salt with a long-chain base. A dye showing is also included. For example, acid dyes, direct dyes, and salt forming dyes of reactive dyes and long-chain amines are known. The oil-soluble dye is not limited to the following, but particularly preferable specific examples thereof include Valifast Yellow 412 manufactured by Orient Chemical Industry Co., Ltd.
0, Valifast Yellow 3150, Va
lift Yellow 3108, Valifa
st Yellow 2310N, Valifast
Yellow 1101, Valifast Red
3320, Valifast Red 3304, Va
liftast Red 1306, Valifast
Blue 2610, Valifast Blue 26
06, Valifast Blue 1603, Oil
Yellow GG-S, Oil Yellow 3
G, Oil Yellow 129, Oil Yellow
w 107, Oil Yellow 105, Oil
Scarlet 308, Oil Red RR, Oi
l Red OG, Oil Red5B, Oil Pi
nk 312, Oil Blue BOS, Oil B
lue 613, Oil Blue 2N, Oil B
rack BY, OilBlack BS, Oil B
rack 860, Oil Black 5970, O
il Black 5906, Oil Black 5
905, Kayase Yell manufactured by Nippon Kayaku Co., Ltd.
ow SF-G, Kayaset Yellow K-
CL, Kayaset Yellow GN, Kaya
set Yellow AG, Kayaset Ye
low 2G, KayasetRed SF-4G,
Kayaset Red K-BL, Kayaset
Red A-BR, Kayase Magenta 3
12, Kayaset Blue K-FL, FS Yellow 1015, FS manufactured by Arimoto Chemical Industry Co., Ltd.
Magenta 1404, FS Cyan 152
2, FS Blue1504, C.I. I. Solven
t Yellow 88, 83, 82, 79, 56, 2
9, 19, 16, 14, 04, 03, 02, 01, C.I.
I. Solvent Red 84: 1, C.I. I. So
lvent Red 84, 218, 132, 73, 7
2, 51, 43, 27, 24, 18, 01, C.I. I. S
event Blue 70, 67, 44, 40, 3
5, 11, 02, 01, C.I. I. Solvent Bl
ack 43, 70, 34, 29, 27, 22, 7,
3, C.I. I. Solvent Violet 3, C.I.
I. Solvent Green 3 and 7, etc. are mentioned. In addition, JP-A-9-277693 and 10-20
Metal complex dyes as shown in Nos. 559 and 10-30061 are also preferably used, and a preferable structure is represented by the following general formula (1).

In the general formula (1) M (Dye) ₁ (A) _m , M represents a metal ion, and Dye represents a dye capable of forming a coordinate bond with a metal. A represents a ligand other than the dye, 1 represents 1 to 3 and m represents 0, 1, 2, 3. When m is 0, 1 represents 2 or 3, and in that case, Dye may be the same or different.

Examples of the metal ion represented by M include metals belonging to Groups I to VIII of the periodic table, for example, Al, Co and C.
r, Cu, Fe, Mn, Mo, Ni, Sn, Ti, P
Ions of t, Pd, Zr and Zn are mentioned. Color,
Ions of Ni, Cu, Cr, Co, Zn, and Fe are particularly preferable from the viewpoint of various durability. Particularly preferred is Ni ion.

Although various dye structures are conceivable as the dye represented by Dye and capable of forming a coordinate bond with the metal, a conjugated methine dye, an azomethine dye, and a dye having a coordination group in the azo dye skeleton are preferable.

Disperse dyes can be used as the oil-soluble dyes, and the disperse dyes are not limited to the following, but particularly preferable specific examples include C.I. I. Disperse Yellow 5, 42, 54, 64, 79, 82, 8
3, 93, 99, 100, 119, 122, 124, 1
26, 160, 184: 1, 186, 198, 199,
204, 224 and 237; C.I. I. Disperse Orange 13, 29, 31: 1, 33, 49, 54, 55,
66, 73, 118, 119 and 163; C.I. I. Disperse Red 54, 60, 72, 73, 86, 88,
91, 92, 93, 111, 126, 127, 134,
135, 143, 145, 152, 153, 154, 1
59, 164, 167: 1, 177, 181, 204,
206, 207, 221, 239, 240, 258, 2
77, 278, 283, 311, 323, 343, 34
8, 356 and 362; C.I. I. Disperse Violet 33; C.I. I. Disperse Blue 56, 60, 7
3, 87, 113, 128, 143, 148, 154,
158, 165, 165: 1, 165: 2, 176, 1
83, 185, 197, 198, 201, 214, 22
4, 225, 257, 266, 267, 287, 35
4, 358, 365 and 368 and C.I. I. Examples include Disperse Green 6: 1 and 9.

Other oil-soluble dyes include phenol,
Azomethines obtained by oxidative coupling of amino compounds such as p-phenylenediamines or p-diaminopyridines to naphthols, cyclic methylene compounds such as pyrazolone and pyrazolotriazole, or so-called couplers such as open chain methylene compounds. Dyes, indoaniline dyes and the like are also preferable. Particularly, as the magenta dye, an azomethine dye having a pyrazolotriazole ring is preferable.

The pigment is not limited to the following, but as a particularly preferred specific example, the carbon black pigment may be No. 1 manufactured by Mitsubishi Kasei. 2300, No. 90
0, MCF-88, No. 33, No. 40, No. Four
5, No. 52, MA7, MA8, MA100, No.
2200B, Raven 700, Ra manufactured by Colombia
ven 5750, Raven 5250, Raven
5000, Raven 3500, Raven 125
5. Cabot's Regal 400R, Regal
330R, Regal 660R, Mogul L,
Monarch 700, Monarch 800, Mo
narch 880, Monarch 900, Mona
rch 1000, Monarch 1100, Mon
arch 1300, Monarch 1400, Degussa Color Black FW1, Color
Black FW2, Color Black FW2
V, Color Black FW18, Color
Black FW200, Color Black S
150, Color Black S160, Colo
r Black S170, Printex 35, P
printexU, Printex V, Printex
140U, Printex 140V, Specia
l Black 6, Special Black
5, Special Black 4A, Specia
l Black 4, Maxsorb G-40, Maxsorb G-15, Maxsorb G-08 and the like manufactured by Kansai Thermochemical Co., Inc. can be used.

As the yellow pigment, C.I. I. Pigm
ent Yellow 1, C.I. I. Pigment
Yellow 2, C.I. I. Pigment Yell
ow3, C.I. I. Pigment Yellow 1
2, C.I. I. Pigment Yellow 13, C.I.
I. Pigment Yellow 14, C.I. I. P
igment Yellow 16, C.I. I. Pigm
ent Yellow 17, C.I. I. Pigment
Yellow 73, C.I. I. Pigment Ye
low 74, C.I. I. Pigment Yellow
w 78, C.I. I. Pigment Yellow 8
3, C.I. I. Pigment Yellow 93,
C. I. Pigment Yellow 95, C.I.
I. Pigment Yellow 97, C.I. I. P
igment Yellow 98, C.I. I. Pigm
ent Yellow 114, C.I. I. Pigmen
tYellow 128, C.I. I. Pigment Y
ellow 129, C.I. I. Pigment Yel
low 138, C.I. I. Pigment Yellow
w154, magenta pigments include C.I. I. Pigm
ent Red 5, C.I. I. Pigment Red
7, C.I. I. Pigment Red 12, C.I.
I. Pigment Red 48 (Ca), C.I. I.
Pigment Red 48 (Mn), C.I. I. Pi
gment Red 57 (Ca), C.I. I. Pigm
ent Red 57: 1, C.I. I. Pigment
Red 122, C.I. I. Pigment Red 1
23, C.I. I. Pigment Red 168, C.I.
I. Pigment Red 184, C.I. I. Pig
ment Red 202, cyan pigments include C.I.
I. Pigment Blue 1, C.I. I. Pigm
ent Blue 2, C.I. I. Pigment Bl
ue 3, C.I. I. Pigment Blue 15:
3, C.I. I. Pigment Blue 15:34,
C. I. Pigment Blue 16, C.I. I. P
igmentBlue 22, C.I. I. Pigment
Blue 60, C.I. I. VatBlue 4, C.I.
I. Vat Blue 60, etc. are mentioned.

A colored fine particle dispersion according to the present invention, or
The colored fine particles having a more preferable core / shell morphology have a polymer amount of 0.5 to 0.5 in the aqueous ink of the present invention.
The content is preferably 50% by mass, and more preferably 0.5 to 30% by mass. If the amount of the above-mentioned polymer compounded is less than 0.5% by mass, the ability to protect the color material is not sufficient, and if it exceeds 50% by mass, the storage stability of the suspension as an aqueous ink is lowered, or the nozzle tip portion is deteriorated. Since there is a case where clogging of the printer head may occur due to thickening of the ink and aggregation of the suspension due to the evaporation of the ink, the above range is preferable.

On the other hand, the coloring material such as the dye and pigment is preferably blended in the ink in an amount of 1 to 30% by mass, more preferably 1.5 to 25% by mass. If the blending amount of the coloring material is less than 1% by mass, the printing density is insufficient, and if it exceeds 30% by mass, the stability of the suspension with time is deteriorated and the particle size tends to increase due to aggregation or the like. It is preferably within the range.

The water-based ink of the present invention comprises a suspension of a polymer in which water is used as a medium and in which the above-mentioned coloring material is encapsulated. The suspension contains various conventionally known additives such as wetting agents such as polyhydric alcohols and inorganic salts. , Surfactants, antiseptics, antifungal agents, pH adjusters, antifoaming agents such as silicone,
If necessary, a viscosity modifier or a chelating agent such as EDTA, an oxygen absorbent such as sulfite, and the like may be added.

Here, examples of the wetting agent include ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, glycerin, diethylene glycol diethyl ether, diethylene glycol mono-n-butyl ether, ethylene glycol monomethyl ether, ethylene. Such as glycol monoethyl ether, ethylene glycol monobutyl ether, methyl carbitol, ethyl carbitol, butyl carbitol, ethyl carbitol acetate, diethyl carbitol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, etc. Polyhydric alcohol and its ether, ace Or one or more of nitrogen-containing compounds such as salts, N-methyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, triethanolamine, formamide and dimethylformamide, and dimethyl sulfoxide. be able to. The amount of these wetting agents to be added is not particularly limited, but it is preferably 0.1 to 50% by mass, and more preferably 0.1 to 30% by mass in the aqueous ink.

An inorganic salt may be added to the ink in order to keep the viscosity of the ink stable and to improve the color development. Examples of the inorganic salt include sodium chloride, sodium sulfate, magnesium chloride, magnesium sulfide and the like. When carrying out the present invention, the present invention is not limited thereto.

The emulsifier and the dispersant are not particularly limited, but having an HLB value of 8 to 18 has an effect of suppressing the increase in the particle size of the suspension from the viewpoint of manifesting the effect. It is preferable from the point.

As the surfactant, any of cationic, anionic, amphoteric and nonionic can be used.

The emulsifier or dispersant is preferably an anionic surfactant or a polymeric surfactant, and an anionic surfactant is particularly preferable.

The activator for adjusting the surface tension of the ink is preferably a nonionic surfactant.

Examples of the cationic surfactants include aliphatic amine salts, aliphatic quaternary ammonium salts, benzalkonium salts, benzethonium chloride, pyridinium salts and imidazolinium salts.

As the anionic surfactant, fatty acid soap, N-acyl-N-methylglycine salt, N-acyl-
N-methyl-β-alanine salt, N-acylglutamate, alkyl ether carboxylate, acylated peptide, alkylsulfonate, alkylbenzenesulfonate, alkylnaphthalenesulfonate, dialkylsulfosuccinate ester salt, alkylsulfo Acetate, α-olefin sulfonate, N-acylmethyl taurine, sulfated oil, higher alcohol sulfate ester salt, secondary higher alcohol sulfate ester salt, alkyl ether sulfate salt, secondary higher alcohol ethoxy sulfate, polyoxy Examples thereof include ethylene alkyl phenyl ether sulfate, monoglycol sulfate, fatty acid alkylolamide sulfate ester salt, alkyl ether phosphate ester salt, and alkyl phosphate ester salt.

Examples of the amphoteric surfactant include carboxybetaine type, sulfobetaine type, aminocarboxylic acid salts, imidazolinium betaine and the like.

As the nonionic surfactant, polyoxyethylene alkyl ether, polyoxyethylene secondary alcohol ether, polyoxyethylene alkylphenyl ether (for example, Emulgen 911), polyoxyethylene sterol ether, polyoxyethylene lanolin derivative, Polyoxyethylene polyoxypropylene alkyl ether (eg Newpol PE-6
2), polyoxyethylene glycerin fatty acid ester,
Polyoxyethylene castor oil, hydrogenated castor oil, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, polyethylene glycol fatty acid ester, fatty acid monoglyceride, polyglycerin fatty acid ester, sorbitan fatty acid ester, propylene glycol fatty acid ester, sucrose fatty acid ester , Fatty acid alkanolamides, polyoxyethylene fatty acid amides, polyoxyethylene alkylamines, alkylamine oxides, acetylene glycol, acetylene alcohol and the like. In addition, as the surfactant, for example, the dispersant DEMOL SN manufactured by Kao Co., Ltd.
B, MS, N, SSL, ST, P (trade name) are also included.

When these surfactants are used, they can be used alone or as a mixture of two or more kinds. By adding them in the range of 0.001 to 1.0% by mass with respect to the total amount of the ink, The surface tension of the ink can be adjusted arbitrarily. When carrying out the present invention, the present invention is not limited thereto. In order to maintain the long-term storage stability of the ink, an antiseptic agent and a mildewproofing agent may be added to the ink.

The following water-soluble resins can be used as the polymer surfactant, which is preferable from the viewpoint of ejection stability. Preferably used as the water-soluble resin, styrene-acrylic acid-acrylic acid alkyl ester copolymer, styrene-acrylic acid copolymer, styrene-maleic acid-acrylic acid alkyl ester copolymer, styrene-maleic acid copolymer Coal, styrene-methacrylic acid-acrylic acid alkyl ester copolymer, styrene-methacrylic acid copolymer, styrene-maleic acid half ester copolymer, vinylnaphthalene-acrylic acid copolymer, vinylnaphthalene-maleic acid copolymer Etc. can be mentioned. Other examples of the polymer surfactant include acrylic acid-styrene resin such as John Cryl (Johnson Co.). These polymeric surfactants can be used in combination of two or more kinds.

The addition amount of each of the above polymeric surfactants to the total amount of the dispersed ink is preferably 0.1 to 10% by mass, more preferably 0.3 to 5% by mass. If the compounding amount is less than 0.01% by mass, it is difficult to reduce the particle size of the suspension, and if it exceeds 10% by mass, the particle size of the suspension may be increased or the suspension stability may be deteriorated to cause gelation. .

As the preservatives and antifungal agents, aromatic halogen compounds (for example, Preventol CMK, chloromethylphenol, etc.), methylene dithiocyanate,
Examples thereof include halogen-containing nitrogen-sulfur compounds and 1,2-benzisothiazolin-3-one (for example, PROXEL GXL), but the present invention is not limited thereto.

In order to keep the ink stable, a pH adjuster may be added to the ink. As the pH adjuster, hydrochloric acid, acetic acid, citric acid, sodium hydroxide, potassium hydroxide or the like can be diluted with water or used as it is.

The defoaming agent is not particularly limited, and commercially available products can be used. Examples of such commercially available products include KF96, 6 manufactured by Shin-Etsu Silicone Co., Ltd.
6, 69, KS68, 604, 607A, 602, 60
3, KM73, 73A, 73E, 72, 72A, 72
C, 72F, 82F, 70, 71, 75, 80, 83
A, 85, 89, 90, 68-1F, 68-2F (brand name) etc. are mentioned. The compounding amount of these compounds is not particularly limited, but 0.001 to 2 mass% is preferably compounded in the aqueous ink of the present invention. If the compounding amount of the compound is less than 0.001% by mass, bubbles are likely to be generated during ink preparation, and it is difficult to remove small bubbles in the ink, and if it exceeds 2% by mass, the generation of bubbles is suppressed. , When printing
Since repellency may occur in the ink and print quality may deteriorate, it is preferable to set it within the above range.

Next, the emulsification method used in the production of the ink of the present invention will be described. The ink of the present invention is
For example, various emulsification methods can be used in the production of the coloring material particles to be the core, or in the case of producing the core-shell colored fine particles directly from the pigment particles and the polymer. Various methods can be used as the emulsification method. Examples of these are summarized, for example, in the description on page 86 of “Progress of Functional Emulsifiers / Emulsification Technologies and Their Application and Development”. In the present invention, it is particularly preferable to use an ultrasonic dispersing device, a high speed rotating shearing device, or an emulsifying dispersing device using high pressure for forming the dye core. A media disperser is preferred for pigments.

Two types of so-called batch type and continuous type can be used for ultrasonic emulsification and dispersion. The batch type is
It is suitable for preparing a relatively small amount of sample, and the continuous method is suitable for preparing a large amount of sample. In the continuous system, for example, UH-60
It is possible to use a device such as 0SR (manufactured by SMT Co., Ltd.). In the case of such a continuous system, the irradiation time of ultrasonic waves can be obtained by the formula: volume of dispersion chamber / flow velocity × number of circulations. When there are a plurality of ultrasonic irradiation devices, the total irradiation time can be calculated. The ultrasonic wave irradiation time is actually 10,000 seconds or less. Also, 100
If it is required to be 00 seconds or more, the load on the process is heavy, and it is necessary to shorten the emulsification / dispersion time by reselecting the emulsifier in practice. Therefore, 10,000 seconds or more is not necessary. More preferably, it is 10 seconds or more and 2000 seconds or less.

Examples of the emulsification / dispersion device using high-speed rotary shearing include a disper mixer as described on pages 255-256 of “Advancement of functional emulsifier / emulsification technology and its application development” and a page 251. A homomixer as described above, an ultramixer as described on page 256, or the like can be used. These types can be used properly depending on the liquid viscosity at the time of emulsion dispersion. In these emulsifying dispersers using high-speed rotary shearing, the rotation speed of the stirring blade is important. In the case of a device having a stator, the clearance between the stirring blade and the stator is usually about 0.5 mm, which cannot be extremely narrowed.
The shear force mainly depends on the peripheral speed of the stirring blade. Peripheral speed is 5
If it is m / S or more and 150 m / S or less, it can be used in the emulsification / dispersion of the present invention. This is because when the peripheral speed is slow, it is often impossible to reduce the particle size even if the emulsification time is extended, and it is necessary to extremely improve the performance of the motor in order to achieve 150 m / S. More preferably, it is 20 to 100 m / S.

For emulsification and dispersion by high pressure, LAB2000
(Made by SMT) can be used, but the emulsification /
Dispersion capacity depends on the pressure applied to the sample. Pressure is
10 ^FourkPa ~ 5 x 10^FiveA range of kPa is preferred. Well
If necessary, emulsify and disperse several times to obtain the desired particle size.
Obtainable. If the pressure is too low, repeat emulsification
In many cases, the target particle size cannot be achieved even if
Also, the pressure is 5 × 10^FiveIn order to make kPa
It is very practical and impractical. More preferably 5
× 10^FourkPa ~ 2 x 10^FiveIt is in the range of kPa.

These emulsifying / dispersing devices may be used alone, but may be used in combination as required. A colloid mill, a flow jet mixer, etc., alone cannot achieve the object of the present invention, but the combination with the device of the present invention can enhance the effects of the present invention such as enabling emulsification / dispersion in a short time. is there.

The ink-jet head to be used when an image is formed by ejecting the water-based ink for ink-jet recording of the present invention may be either an on-demand type or a continuous type. Further, as a discharge method, an electro-mechanical conversion method (for example, single cavity type, double cavity type, bender type, piston type, shear mode type,
Shared wall type, etc., electricity-heat conversion method (for example, thermal inkjet type, bubble jet (R))
Any ejection method such as a mold) may be used.

In the image forming method using the water-based ink for ink-jet recording of the present invention, for example, by a printer or the like loaded with the water-based ink for ink-jet recording,
By ejecting ink as droplets from an inkjet head based on a digital signal and attaching the droplets to an ink receptor, for example, an inkjet print having an inkjet recording image formed on an inkjet image recording medium can be obtained.

Examples of the ink jet image recording medium include plain paper, coated paper, cast coated paper, glossy paper,
Both a glossy film and an OHP film can be used, and among them, a recording medium having a so-called void layer in which a porous layer is formed is preferable. The material or shape of the support described above is not particularly limited, and may have a three-dimensional structure in addition to, for example, a sheet-shaped support.

The water-based ink of the present invention can be used not only as an ink for ink jet recording, but also as an ink for writing instruments such as general fountain pens, ballpoint pens and felt-tip pens. The suspension of the present invention can be dried to obtain fine powder. The obtained powder can also be used as a toner for electrophotography.

[0096]

EXAMPLES Next, the colored fine particles of the present invention and the water-based inkjet ink using the same will be specifically described with reference to Examples, but it goes without saying that the present invention is not limited to these Examples. Absent.

Example 1 (Synthesis example 1) 5 g of polyvinyl butyral of core-shell type dye-colored fine particles (3000, manufactured by Denki Kagaku Co., Ltd.)
K; average degree of polymerization 800), 3 g of C.I. I. Solven
t Yellow 162, 3 g of C.I. I. Solve
nt Yellow 29 and 50 g of ethyl acetate were placed in a separable flask and stirred to completely dissolve the polymer and dye. Next, 100 g of an aqueous solution containing 0.5 g of sodium lauryl sulfate was added dropwise, and then emulsified for 300 seconds using an ultrasonic disperser (UH-150 manufactured by SMT Co., Ltd.). Then, ethyl acetate was removed under reduced pressure to obtain an aqueous dispersion of colored fine particles impregnated with two kinds of dyes. After replacing the inside of the flask with N ₂ , add 0.1 to this dispersion.
After adding and dissolving 5 g of potassium persulfate, heating with a heater to 70 ° C., 2 g of styrene and 1 g of 2-
The mixture was reacted for 7 hours while dropping a mixed solution of hydroxyethyl methacrylate to coat the colored fine particles with a polymer shell to obtain a core / shell type dye-colored fine particle aqueous dispersion. The average particle diameter was 91 nm. The particle size is a volume average particle size using a laser particle size analysis system manufactured by Otsuka Electronics.

(Synthesis Example 2) Polyvinyl butyral of 5 g of core-shell type dye-colored fine particles (manufactured by Sekisui Chemical Co., Ltd., BL-
S; average degree of polymerization 350), 5 g of dye A, 1 g of Oil Pink 312 manufactured by Orient Chemical Industry Co., Ltd., and 50 g of ethyl acetate were placed in a separable flask and stirred to completely dissolve the polymer and the dye. Then, after dropping 100 g of an aqueous solution containing 0.5 g of sodium lauryl sulfate, an ultrasonic disperser (UH-150 manufactured by SMT Co., Ltd.) was used.
Emulsification for 300 seconds. Then, ethyl acetate was removed under reduced pressure to obtain an aqueous dispersion of colored fine particles impregnated with two kinds of dyes. After replacing the inside of the flask with N ₂ , 0.15 g of potassium persulfate was added to and dissolved in this dispersion, and after heating with a heater to 80 ° C., 2 g of styrene and 1 g of 2-hydroxyethyl methacrylate and 0.5
The mixture was allowed to react for 7 hours while dropwise adding a mixed solution of 2-ethylhexyl acrylate (g) to coat the colored fine particles with a polymer shell to obtain a core / shell type dye-colored fine particle aqueous dispersion. The average particle diameter was 89 nm. The particle size is a volume average particle size using a laser particle size analysis system manufactured by Otsuka Electronics.

[0099]

[Chemical 1]

(Synthesis example 3) Polyvinyl butyral of 5 g of core-shell type dye-colored fine particles (manufactured by Sekisui Chemical Co., Ltd., BL-S;
Average degree of polymerization 350), 4 g of Kayaset Blue
K-FL (manufactured by Nippon Kayaku Co., Ltd.), 4 g of FS Blue 1
504 (manufactured by Arimoto Chemical Co., Ltd.) and 50 g of ethyl acetate were placed in a separable flask and stirred to completely dissolve the polymer and dye. After 90 g of an aqueous solution containing 0.5 g of sodium lauryl sulfate was added dropwise and stirred, the mixture was emulsified for 300 seconds using an ultrasonic disperser (UH-150 manufactured by SMT Co., Ltd.). Then, ethyl acetate was removed under reduced pressure to obtain colored fine particles. After substituting the inside of the flask with N ₂ , 0.1 g of potassium persulfate was added and dissolved, and after heating with a heater to 70 ° C., 2 g of styrene and 1
The mixture was allowed to react for 7 hours while dropwise adding a mixed liquid of 2-hydroxyethyl methacrylate (g) to coat the colored fine particles with a polymer shell to obtain a core-shell type dye-colored fine particle aqueous dispersion. The average particle diameter was 81 nm.

(Synthesis Example 4) 5 g of core-shell type dye-colored fine particles of Oil Black BY manufactured by Orient Chemical Co.,
5 g of Oil Black 860, 10 g of monomer composition ratio of styrene / n-butyl methacrylate / 2-hydroxyethyl methacrylate = 60/20/20 copolymer resin and methyl ethyl ketone (MEK) 20 ml
After mixing and dissolving, John Cryl 52 (acrylic /
50 g of ion-exchanged water containing 3 g of styrene resin (manufactured by Johnson Co.) is added to clear mix W motion CLM.
The mixture was emulsified with −0.8 W (manufactured by M Technique Co., Ltd.) for 300 seconds, and methyl ethyl ketone was distilled off under reduced pressure at 45 ° C. to obtain an aqueous dispersion of colored fine particles. The obtained colored fine particle water dispersion was placed in a separable flask, the inside of the flask was replaced with N ₂ , and 0.1 g of potassium persulfate was added to dissolve it. After heating with a heater to 70 ° C., 2 g was further added. Styrene and 1
The mixture was allowed to react for 7 hours while dropping a mixed solution of 2-hydroxyethyl methacrylate (g) to obtain a core-shell type dye-colored fine particle aqueous dispersion. The average particle size was 98 nm.

COMPARATIVE SYNTHESIS EXAMPLE 1 6 g of C.I. I. Solvent Yellow
A comparative dye-colored fine particle water dispersion was synthesized in exactly the same manner except that w 162 was used. Average particle size is 135n
It was m.

Comparative Synthesis Example 2 8 g of Kayaset Blue K-FL as a dye in the formulation of Synthesis Example 3 was used.
A comparative dye-colored fine particle water dispersion was synthesized with the same formulation except that (Nippon Kayaku Co., Ltd.) was used. Average particle size is 1
It was 54 nm.

(Synthesis Example 5) Pigment colored fine particles 20 g of methyl ethyl ketone, 5 g of glycerin, C.I. I.
Pigment Yellow 128 (3 g), C.I.
I. Pigment Yellow 129 (3 g), a monomer composition ratio of styrene / acrylic acid / 2-hydroxyethyl methacrylate = 80/5/15 (6 g) of a copolymer resin, and ion-exchanged water (40 g) in a mixed solution having an average particle diameter of 0.3 mm. Add 250 g of zirconia beads and use System Zeta LMZ-2 (manufactured by Ashizawa Seisakusho) to
Time dispersion was performed. After the dispersion was completed, the zirconia beads were filtered out to obtain a pigment dispersion. 40 ml of water was added to this dispersion to dilute it, and then methyl ethyl ketone was removed by distillation under reduced pressure to obtain a pigment-colored fine particle dispersion. Average particle size is 15
It was 6 nm.

(Synthesis example 6) Pigment coloring fine particles C.I. I. 5 g of Pigment Blue 15: 3,
C. I. Pigment Blue 15:34 to 5
g, a polymerizable surfactant Latemur (Kao Co., Ltd.) 5g, and ion-exchanged water 50g are mixed, and 250 g of zirconia beads having an average particle diameter of 0.3 mm is further added, and System Zeta LMZ-2 (manufactured by Ashizawa Seisakusho). ) Dispersed. 0.1 g of potassium persulfate was added to the dispersion to dissolve it, and after heating to 80 ° C., the mixture was reacted for 7 hours while dropping a mixed solution of 3 g of styrene and 2 g of 2-hydroxyethyl methacrylate to form a polymer shell. A core / shell type pigmented fine particle dispersion was formed. Average particle size is 9
It was 7 nm.

(Comparative Synthetic Example 3) C.I. I. Pigment Yellow12
A comparative pigment-colored fine particle water dispersion was synthesized in exactly the same manner except that 6 g of 8 was used. The average particle size was 190 nm.

(Comparative Synthesis Example 4) C.I. I. Pigment Blue 15:
A comparative pigment-colored fine particle water dispersion was synthesized in exactly the same manner except that 10 g of 3 was used. Average particle size is 171 nm
Met.

<Performance Evaluation Test><Test1> Dye-Colored Fine Particles The dye-colored fine particle water dispersions (Synthesis Examples 1 to 4 and Comparative Synthesis Examples 1 and 2) synthesized by the above-mentioned method were used in a coloring material content of 2%. 15% ethylene glycol, 15% glycerin, 0.3% sulfinol 465, 0.3% of the mixture, and the remaining pure water were mixed to prepare an ink, which was then filtered through a 0.8 μm membrane filter to remove dust and coarse particles. The particles were removed to obtain inkjet inks 1 to 6. In order to evaluate dispersion stability and ink storability, the particle size change rate,
The filterability was evaluated.

(Ratio of particle size change) Each ink prepared was heated to 60 ° C.
After storing for 1 week at (average particle size after heating / average particle size before heating) x 1
00 (%) was determined as the particle size change rate.

(Filterability) After the ink was stored at 60 ° C. for 1 week, 5 ml of each ink was sampled and filtered through a 0.8 μm cellulose acetate membrane filter. Those that were able to be filtered were rated as ◯ (allowable level), and those that could be filtered in an amount less than half were rated as x (not acceptable level).

Further, using each of the prepared inks, an ink jet printer (manufactured by Epson Corp., model number PM-800) was used to produce Konica Photojet Paper Photolike.
Printing was performed on QP glossy paper (manufactured by Konica Corporation), and the ejection stability, the maximum density of the obtained image, and the light resistance were evaluated.
The results are shown in Table 1.

(Discharge Stability) ○ (acceptable level) when the nozzle was not continuously ejected for 10 minutes or more with the ink jet printer, and × (impossible level) when it was less than that.
And

(Maximum Density) The respective color densities measured using X-Rite 900 (manufactured by Nippon Flat Plate Equipment Co., Ltd.) are shown.

(Lightfastness) A sample was prepared in which the concentration was changed stepwise, and a low temperature Xe weather meter X was used as a tester.
L75 (manufactured by Suga Test Instruments Co., Ltd.) was used. Concentration change is X
-It measured using Rite900 (made by Nippon flat plate equipment). The density change in the vicinity of print density 1 was measured. For samples lacking in concentration, the change in concentration at the highest concentration was measured. When the coloring material is a dye, after 1 week of testing, the one remaining 70% or more from the original density is ◎, 50% or more,
Those that remained less than 70% were rated as O (acceptable level), and those below were rated as X (impossible level).

[0115]

[Table 1]

As is clear from Table 1, the inks 1 to 4 using the dye-colored fine particle aqueous dispersion of the present invention are inks excellent in particle size change rate, filterability and dispersion stability, and storage stability. I understand. On the other hand, Comparative Inks 5 and 6 were inks in which the dye was precipitated during the preparation of the aqueous dispersion and during the preparation of the ink, and the particle size change rate after heating and storage was large and the stability was poor.

In the test by the printer, the dispersion stability was reflected and the ink of the present invention had no problem in the ejection stability.
Although the maximum density was high and the light resistance was excellent, the comparative inks were inferior in ejection stability, maximum density, and light resistance.

<Test 2> Pigment Colored Fine Particles An aqueous dispersion of pigment colored fine particles synthesized by the above method (Synthesis Examples 5 and 6, Comparative Synthetic Examples 3 and 4) had a coloring material content of 3%, ethylene glycol 15%, Glycerin 15%, triethylene glycol monobutyl ether 3%, sulfinol 465 0.5%, weighed and prepared so that the rest is pure water, and further filtered through a 2 μm membrane filter to remove dust and coarse particles. Inkjet inks 7 to 10 were obtained. Table 2 shows the results of evaluation of performance as in Test 1. However, in the light resistance test, when the coloring material is a pigment, after 40 days of testing, those remaining 90% or more from the original density were evaluated as ◯ (acceptable level), and those below were evaluated as x (impossible level). .

[0119]

[Table 2]

As is clear from Table 2, the ink of the present invention is excellent in the stability of the dispersion, and the ejection stability, print density, and
The ink was excellent in light resistance.

<Test 3> Dye-colored fine particle ink set Dye-colored fine particle produced by the above method (Synthesis Examples 1 to 4)
The amounts of the absorbances listed in Table 3 were weighed, and ethylene glycol 10%, glycerin 20%, Surfynol 46
5% was adjusted to 0.3% and mixed so as to be pure water, and the mixture was mixed, and further filtered through a 0.8 μm membrane filter to remove dust and coarse particles to obtain inkjet inks 11 to 16. Ink set 1 was formed by combining these inks. Further, an ink set using an inkjet ink 17 (absorbance 1500) prepared from the following carbon black dispersion instead of the ink 16 was used as an ink set 2.

<Preparation of carbon black dispersion> Carbon black 20% by mass Styrene-acrylic acid copolymer (molecular weight 7,000, acid value 150) 10% by mass Glycerin 10% by mass Ion-exchanged water 60% by mass Each of the above additives Were mixed and dispersed using a horizontal bead mill (System Zetamini manufactured by Ashizawa Co., Ltd.) in which 0.3 mm zirconia beads were filled at a volume ratio of 60% to obtain a carbon black dispersion. The average particle size of the obtained black pigment was 75 nm.

The carbon black dispersion produced by the above method was weighed in such an amount that the absorbance (1500) listed in Table 3 was reached, and ethylene glycol 10%, glycerin 20%, Surfynol 465 0.3%, and the balance The mixture was adjusted to be pure water, mixed, and filtered through a 0.8 μm membrane filter to remove dust and coarse particles, to obtain an inkjet ink 17.

[0124]

[Table 3]

Each ink set shown in Table 3 was loaded in an ink jet printer PM-770C manufactured by Seiko Epson Corporation, and Konica Photo Jet Paper Photoli was used.
It was printed on keQP glossy paper (manufactured by Konica Corporation).
The printed image is yellow, magenta, cyan and black wedge images, 1 cm wide Y, M, C,
3A and 3B are a test chart and a portrait image of a person in which B, G, R, and Bk are drawn respectively. For comparison, PM-7
The same image was printed with 70C genuine ink and the color reproducibility was evaluated by visual inspection by 10 people. As a result, it was confirmed that the color reproducibility was comparable to that of the dye, although the gloss was slightly inferior. . Further, Table 4 shows the density 1.0 portion of each color wedge image of these prints,
Similar to the above, as a testing machine, low temperature Xe weather meter X
The results of light resistance test for 1 week using L75 (manufactured by Suga Test Instruments) were summarized. The residual rate (%) from the original concentration is shown.

[0126]

[Table 4]

The ink set 1 using the colored fine particle water dispersion containing the dye of the present invention and the ink set 2 using only the carbon black dispersion of the black ink are highly durable inks excellent in light resistance balance of respective colors. You can see that it is a set.

[0128]

EFFECTS OF THE INVENTION A water-based ink for inkjet ink having good ejection stability and excellent storage stability can be obtained, and by using this, an image having excellent fastness can be obtained.

Claims (12)

[Claims] 1. A colored fine particle water dispersion containing a coloring material and a resin, wherein two or more kinds of coloring materials are simultaneously contained in the resin. 2. The colored fine particle water dispersion according to claim 1, which contains only a dye as a coloring material. 3. The colored fine particle water dispersion according to claim 1, which contains both a dye and a pigment as a coloring material. 4. The colored fine particle water dispersion according to claim 1, which contains only a pigment as a coloring material. 5. The difference in SP value between color materials is 4.0 (Jou
le / cm ³ ) ^{1/2 or} less.
Water dispersion of colored fine particles of. 6. A colored fine particle water dispersion, wherein the colored fine particles in the colored fine particle water dispersion according to any one of claims 1 to 5 are coated with a polymer shell to form a core / shell structure. . 7. The colored fine particle water dispersion according to any one of claims 1 to 6, wherein the resin contains polyvinyl butyral. 8. The colored fine particle water dispersion according to claim 1, wherein the average particle diameter of the colored fine particles is 100 nm or less. 9. An aqueous ink comprising the colored fine particle water dispersion according to any one of claims 1 to 8. 10. The water-based ink according to claim 9, which is an inkjet ink. 11. An image forming method, characterized in that the ink according to claim 10 is ejected as droplets from an ink jet head based on a digital signal and adhered to an ink receiving medium. 12. An ink set for a multicolor ink jet, which is a combination of two or more different color inks,
At least one kind of ink has an SP value difference of 4.0 (Jo
An ink set comprising a colored fine particle water dispersion obtained by mixing a plurality of dyes having an amount of ule / cm ³ ) ^{1/2 or} less.