JP2003238840A - Colored particulate dispersion, ink for inkjet and method for forming inkjet image - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a colored particulate dispersion excellent in ink preservability and capable of forming an image with improved blurring resis tance and light resistance, and to provide an ink for inkjet and a method for forming an inkjet image. <P>SOLUTION: This colored particulate dispersion comprises at least one kind of colored particulates selected from a colored particulate comprising a resin containing a color material, a colored particulate comprising a resin coated with a color material and a colored particulate comprising a resin containing a color material and further coated with a resin. The colored particulate has nondetachable polar groups on the surface and the number of which is 0.2 to 3 per 1 nm<SP>2</SP>at pH 9. <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 a colored fine particle dispersion, an inkjet ink and an inkjet image forming method, and relates to a colored fine particle dispersion, an inkjet ink and an inkjet image forming method for improving ink storability, image bleeding and light resistance. It is about the method.

[0002]

2. Description of the Related Art Ink jet recording is a technique for ejecting minute droplets of ink by various operating principles and adhering them to a recording medium to record images, characters, etc. It has an advantage that it can be easily colored.

In addition, due to recent technological advances, ink jet printing using dye ink is accelerating its widespread use with the high image quality approaching that of silver halide photography and the cost reduction of the apparatus.

The dye is soluble in a solvent, and the dye molecule is colored in a molecular state or a cluster state. Therefore,
Since the environment of each molecule is similar, its absorption spectrum is sharp, and it exhibits high purity and vivid color. Furthermore, since there is no granular pattern due to particles and neither scattered light nor reflected light is generated, it is possible to obtain an inkjet image having high transparency and a clear hue.

On the other hand, however, when the molecules are destroyed by a photochemical reaction or the like, the decrease in the number of molecules is reflected in the coloring density as it is, so that the light resistance is poor. Although an ink jet recorded image using a dye ink has a high image quality, the image quality is largely deteriorated due to storage over time, and a technique that surpasses silver salt photography from the viewpoint of image storability has not yet appeared.

In contrast to dye inks, pigment inks using pigments having good light resistance as colorants are used as inks for applications requiring an image resistant to fading by light. However, since the pigment is present as pigment particles as compared with the dye, it is more susceptible to light scattering and gives an image with no sense of transparency, so there is a drawback that the dye does not match the color reproducibility.

As described above, the dye ink is excellent in graininess, glossiness and color reproducibility, but is inferior in light resistance, and conversely, the pigment ink is excellent in light resistance. However, they have contradictory properties such as poor granularity, glossiness, and color reproducibility.

As a measure for solving the problems of the water-based ink using the water-soluble dye as described above, an emulsion,
The addition of resin fine particles such as latex has been studied for a long time. Japanese Patent Application Laid-Open No. 55-18418 proposes a recording agent for ink jet recording to which a latex which is "a kind of colloidal solution in which components such as rubber and resin are dispersed in water in the form of fine particles by an emulsifier" is added. is there. In order to improve light fastness by adding latex as in the patent proposal or to have a bleeding prevention effect,
It is very difficult to secure dispersion stability and discharge stability because more latex than the amount of dye used is required, and to obtain an image comparable to a photographic image in terms of graininess and glossiness. The current situation is that it has not arrived.

In order to solve the problems of low water resistance and light fastness of the water-based ink using the water-soluble dye, a method of coloring the water-dispersible resin with an oil-soluble dye, a hydrophobic dye or the like has been proposed as an ink jet recording. It is made as an ink. For example, JP-A-55-139471 and JP-A-58-4.
No. 5272, JP-A Nos. 3-250069 and 8-253.
No. 720, No. 8-92513, No. 8-183920.
JP-A 2001-11347 and the like propose inks using emulsion-polymerized particles dyed with an oil-soluble dye or dispersed polymerized particles. In a water-based ink using such colored fine particles, the presence of a dye on the particle surface or outside the particle reduces the light resistance effect, and enhances various properties such as dispersion stability, ejection stability, and light fastness. At present, it is difficult to obtain an image that is comparable to a photographic image in terms of graininess and glossiness as the obtained image.

Further, in Japanese Patent Laid-Open No. 2001-19880, colored fine particles impregnated with a chelate dye are proposed to improve printing density, light resistance, color tone and the like, but in this method, a desired photographic image is obtained. Is not enough to get an image comparable to. On the other hand, Japanese Patent Laid-Open No. 2001-139607
Proposes a method of improving clogging of the ink head and adhesion with colored fine particles having a core-shell type double structure impregnated with a chelate dye, but this leaves extraordinary ink storage stability and is comparable to photographic images. It is not at a satisfactory level to obtain light resistance and image quality.

Further, there is known an ink in which a dye ink is dissolved in a resin and dispersed in fine particles in the ink. However, by using a dye as a colored fine particle, the temperature and humidity are higher than those of a normal dye ink. Although the bleeding under and water resistance can be improved, these inks have bleeding resistance during printing,
It has a drawback that the light resistance or transparency is lowered.

Further, as one of the methods for improving the ink storability, if the amount of polar groups on the particle surface is increased to improve the dispersion stability of the ink or the color material dispersion, the light resistance of the image is surely improved. Although improvements in glossiness, color reproducibility and the like are recognized, there is a problem that image blurring increases. On the contrary, when the amount of polar groups on the particle surface is reduced, image bleeding is improved, but light resistance, glossiness, color reproducibility and the like are deteriorated, and it is difficult to satisfy each characteristic.

As described above, the colored fine particle-containing aqueous ink using the dye has a possibility of overcoming the problems of the conventional aqueous ink using the water-soluble dye and the pigment dispersion and realizing high recording quality. However, the ink jet formed image formed by it has a problem that the light fastness level of the image is not a satisfactory quality, and further the blur resistance and transparency are inferior. Development of improved technology is required.

[0014]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is coloring excellent in ink storability and having improved image blur resistance and light resistance of a formed image. A fine particle dispersion, an inkjet ink, and an inkjet image forming method are provided.

[0015]

The above objects of the present invention have been achieved by the following constitutions.

1. Containing at least one kind of colored fine particles selected from colored fine particles made of a resin containing a coloring material, colored fine particles made of a resin coated with a coloring material, and colored fine particles made by further coating the surface of a resin containing a coloring material with a resin. In the colored fine particle dispersion, the number of non-eliminating surface polar groups at pH 9 of the colored fine particles is 0.2 to 1 per nm ^2.
A colored fine particle dispersion comprising three particles.

2. Containing at least one kind of colored fine particles selected from colored fine particles made of a resin containing a coloring material, colored fine particles made of a resin coated with a coloring material, and colored fine particles made by further coating the surface of a resin containing a coloring material with a resin. A colored fine particle dispersion, wherein the colored fine particles have a non-eliminating surface polar group amount at pH 9 of 50% or more of the total polar group amount.

3. Containing at least one kind of colored fine particles selected from colored fine particles made of a resin containing a coloring material, colored fine particles made of a resin coated with a coloring material, and colored fine particles made by further coating the surface of a resin containing a coloring material with a resin. In the colored fine particle dispersion, the number of non-eliminating surface polar groups at pH 9 of the colored fine particles is 0.2 to 1 per nm ^2.
3. The colored fine particle dispersion according to the above item 2, wherein the number is 3.

4. The volume average particle diameter of the colored fine particles is
The colored fine particle dispersion according to any one of items 1 to 3, which has a particle size of 10 to 150 nm.

5. 5. The colored fine particle dispersion according to any one of items 1 to 4, wherein the colored fine particles have a core-shell structure in which the surface of a resin containing a coloring material is further covered with the resin.

6. 6. The colored fine particle dispersion according to any one of items 1 to 5, wherein the colored fine particles have a core-shell structure in which the surface of a resin containing a dye is further coated with the resin.

7. At least one color of ink is
Item 7. An ink-jet ink containing the colored fine particle dispersion according to any one of items 6.

8. Item 8. The inkjet ink according to Item 7, which has a surface tension of 25 or more and 50 mN / m or less.

9. 9. The inkjet ink according to item 7 or 8 above, which has a pH of 6.0 or more and 11.0 or less.

10. The inkjet ink according to any one of items 7 to 9, wherein the content of the ink solvent is 10% by mass or more and 60% by mass or less.

11. An inkjet image forming method, which comprises forming an image using at least one inkjet ink according to any one of items 7 to 10.

12. Using at least one ink-jet ink according to any one of items 7 to 10,
An inkjet image forming method comprising forming an image on a void type porous inkjet recording medium.

The inventors of the present invention have made earnest studies on a method for achieving both ink storability and image bleeding in an inkjet ink containing colored fine particles composed of a coloring material and a resin. Of colored particles having a number of surface polar groups of 0.2 to 3 per 1 nm ² or colored particles having a non-eliminating amount of surface polar groups at pH 9 of 50% or more of the total polar groups were used. The present invention has been completed upon finding that the ink jet ink can satisfy both ink storability and image bleeding. Furthermore, it was surprisingly found that the light resistance can be improved at the same time. The mechanism for improving the light resistance by setting the conditions specified above is not clear at this stage, but the water content inside the particles is reduced by reducing the amount of polar groups inside the particles with respect to the surface of the colored fine particles. As a result, it is presumed that the effect of suppressing the photodecomposition of the coloring material involving water is working.

Further, the volume average particle diameter of the colored fine particles is 10
To 150 nm, the colored fine particles have a core-shell structure in which the surface of a resin containing a coloring material is further coated with a resin, and the colored fine particles have a core-shell structure in which the surface of a resin containing a dye is further coated with a resin. Alternatively, it has been found that the effects of the present invention can be further exhibited by defining the surface tension, pH, and ink solvent content of the inkjet ink within specific ranges, and the present invention has been reached.

The details of the present invention will be described below. In the invention according to claim 1, at least selected from colored fine particles made of a resin containing a coloring material, colored fine particles made of a resin coated with a coloring material, and colored fine particles having a surface of a resin containing a coloring material further coated with a resin. In a colored fine particle dispersion containing one kind of colored fine particles, the colored fine particles have a pH of 9
^{3. The} number of non-detachable surface polar groups in is ^{2 to} 3 per 1 nm ² , and
In the invention according to (3), the colored fine particles are characterized in that the amount of non-eliminating surface polar groups at pH 9 is 50% or more of the total amount of polar groups.

The non-eliminating surface polar group referred to in the present invention is
Polar groups that are chemically bonded to or adsorbed on the colored particles, such as sulfonic acid groups, carboxylic acid groups, hydroxyl groups, amines, phosphoric acid groups, and boric acid groups, do not desorb even when subjected to ultrafiltration. It means a polar group, and specifically, it can be measured by a colloid titration method.

The colloid titration method is based on the principle that positively charged colloidal particles react stoichiometrically with negatively charged colloidal particles to form a precipitate.
Methyl glycol chitosan can be used as the cation colloid reagent and potassium polyvinyl sulfate (PVSK) can be used as the anion colloid reagent. The end point of titration is
For example, a method of judging by the color change of the indicator toluidine blue (TB) from blue to magenta, a method of judging by electric conductivity,
A method of judging by turbidity can be appropriately selected and used.

Further, in the pH range of 2 to 11, a cationic polymer (Cat-Flc) always showing a constant titer.
c), for example, poly (diallyldimethyl-ammonium chloride) solution is preferably used, and in the present invention, Cat-Flcc and PVSK are preferably used as colloid titration reagents.

As a specific method, after diluting the colored fine particle dispersion with water, an appropriate amount of poly (diallyldimethyl-ammonium chloride) solution is added, and toluidine blue solution is added as an indicator, and then potassium polyvinyl sulfate solution is added. Colloidal titration with, and the amount of surface polar groups (μmol
/ G). The number of polar groups per 1 nm ² of surface area of the colored fine particles specified in the present invention is determined by multiplying the measured amount of surface polar groups (μmol / g) by the volume average particle diameter (nm) and dividing by 10,000. In the present invention, the number of non-eliminating surface polar groups at pH 9 is 1n.
The feature is that it is 0.2 to 3 per m ² , but preferably 0.3 to 2.0.

The total polar group amount of the colored fine particle dispersion according to the present invention can be determined by a neutralization titration method. For example, dilute hydrochloric acid is added to the colored fine particle dispersion, ultrasonic dispersion treatment and centrifugal separation treatment are performed. After that, washing with ultrapure water and drying are performed to prepare colored fine particle powder in which the polar groups are in the acid form, a certain amount of sodium hydroxide is added to this colored fine particle powder, and neutralization titration with hydrochloric acid is performed. The total polar group amount (μmo
1 / g) can be calculated. In the present invention,
The amount of non-detachable surface polar groups at pH 9 is 50% or more of the total amount of polar groups, but preferably 6
It is 0 to 99%, more preferably 70 to 99%.

In the colored fine particles, the number of non-eliminating surface polar groups, or the ratio of the amount of surface polar groups to the total amount of polar groups, is not particularly limited as to the means for defining the conditions defined in the present invention. Kind and amount of surfactant and coloring material when preparing a colored fine particle dispersion, composition of core polymer or shell polymer, dissolution condition of the coloring material into the core polymer, synthesis condition of polymer during shelling, coloring fine particles of By appropriately selecting or combining the purification method and the conditions therefor, it is possible to obtain a colored fine particle dispersion satisfying the conditions defined in the present invention.

Next, the colored fine particle dispersion of the present invention will be described in detail. The colored fine particles according to the present invention can be prepared by various methods. For example, a method of dissolving an oil-soluble coloring material in a monomer, emulsifying it in water, and then encapsulating the coloring material in a polymer by polymerization, dissolving the polymer and the coloring material in an organic solvent, and then emulsifying in water and then using an organic solvent. Examples include a method of removing, a method of adding porous polymer fine particles to a coloring material solution, and adsorbing and impregnating the coloring material on the fine particles.
A shelling method of coating those colored fine particles with a polymer can also be used.

The polymer shell may be provided by adding a water-soluble polymer dispersant to the aqueous suspension of the core and adsorbing it, by gradually dropping the monomer and depositing it on the core surface at the same time as the polymerization, or by using an organic solvent. There is a method in which the polymer dissolved in is gradually dropped and adsorbed on the core surface simultaneously with precipitation. A method of forming the core shell in one step is also conceivable. For example, a method in which a core polymer and a dye together with a shell polymer are heated and dissolved, and then suspended and polymerized in water, or emulsion polymerization is performed while gradually dropping the liquid into water containing an active agent micelle. There are ways. Alternatively, there is a method in which a dye is dissolved or dispersed in a monomer that can be a core and a monomer that can be a shell after polymerization, and suspension polymerization or emulsion polymerization is performed.

The colored fine particles according to the present invention are not particularly limited to shelled ones or shelled ones, but in view of the effect of the invention, the invention according to claim 5 is:
It is preferable that the colored fine particles have a core-shell structure in which the surface of the resin containing the coloring material is further covered with the resin. In that case, the amount of polymer used in the shell is preferably 5% by mass or more and 95% by mass or less of the total amount of polymer. 5
When the amount is less than 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. On the other hand, if the shell polymer is too much, the amount of the core polymer is relatively decreased, and the function of protecting the color material is likely to be deteriorated. More preferably, it is 10% by mass or more and 90% by mass or less.

The coloring material is 20% by mass based on the total amount of polymer.
It is preferably not less than 1000% by mass. When the amount of the coloring material is too small compared to the polymer, the image density after ejection does not increase, and when the ratio of the coloring material is high, the polymer protecting ability cannot be sufficiently obtained.

(Evaluation of core-shell formation) In the present invention, it is important to evaluate whether or not a core-shell structure is actually formed. In the present invention, the particle size of each particle is very small, 150 nm or less, so the analysis method is limited from the viewpoint of resolution. A transmission electron microscope (TEM), a time-of-flight secondary ion mass spectrometer (TOF-SIMS), or the like can be applied as an analysis method that meets such a purpose. TE
When observing the colored fine particles core-shelled by M,
The dispersion can be coated on a carbon support film, dried, and observed. Since the TEM observation image is usually monochrome, it is necessary to dye the colored fine particles in order to evaluate whether or not it is core-shelled. The colored fine particles of only the core are dyed, and the TEM observation is performed, and comparison is made with the one provided with the shell. Further, the fine particles provided with the shell and the fine particles not provided with the shell are mixed and dyed, and it is confirmed whether or not the ratio of the fine particles having different degrees of dyeing coincides with the presence or absence of the shell. In TOF-SIMS, it is confirmed that the dye in the vicinity of the surface is reduced by providing the shell on the particle surface as compared with the case where 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 an appropriate dye. By embedding core-shell particles in an epoxy resin, making an ultrathin section with a microtome, and dyeing, core-shell formation can be observed more clearly. When the polymer or dye has an element that can serve as a probe, the composition of the core-shell and the amount of the dye distributed to the core and the shell can be estimated by TEM.

In the invention according to claim 4, the colored particles preferably have a volume average particle diameter of 10 to 150 nm, preferably 20 to 120 nm, and particularly preferably 20.
It is preferable that the volume-average particle diameter defined by the present invention can exert the effect of the present invention at all.

The volume average particle size can be measured by a commercially available particle size measuring device using, for example, a light scattering method, an electrophoresis method, a laser Doppler method, etc. , Shimadzu laser diffraction particle size analyzer SLAD1100, particle size analyzer (HOR
IBA LA-920), Zetasizer 1000 manufactured by Malvern Instruments Ltd., and the like.

The polymer used for the colored fine particles has a number average molecular weight of 500 to 100,000, particularly 1.
000 to 30,000, the coating film strength after printing,
It is preferable in terms of its durability and suspension formability.

Various Tg values can be used for the polymer, but it is preferable to use at least one of the polymers having a Tg of 10 ° C. or higher.

In the present invention, generally known polymers can be used, but particularly preferred polymers include a polymer containing an acetal group as a main functional group, a polymer containing a carbonic acid ester group and a hydroxyl group. And a polymer having an ester group, particularly the polymer constituting the outermost shell portion,
It preferably has a hydroxyl group. The above-mentioned polymer may have a substituent, and the substituent is linear,
It may have a branched or cyclic structure. Various polymers having the above-mentioned functional group are commercially available, but they can be synthesized by a conventional method. Also,
These copolymers can also be obtained by, for example, introducing an epoxy group into one polymer molecule, and then polycondensing it with another polymer, or performing graft polymerization using light or radiation.

A polyvinyl butyral resin is preferable as the polymer containing acetal as a main functional group. For example, Denki Kagaku Kogyo Co., Ltd. # 2000-L, # 3000-1, # 3000-2,
# 3000-4, # 3000-K, # 4000-1, #
4000-2, # 5000-A, # 6000-C, # 6
000-EP or BL-1, B manufactured by Sekisui Chemical Co., Ltd.
L-1H, BL-2, BL-2H, BL-5, BL-1
0, BL-S, BL-SH, BX-10, BX-L, B
M-1, BM-2, BM-5, BM-S, BM-SH,
BH-3, BH-6, BH-S, BX-1, BX-3,
BX-5, KS-10, KS-1, KS-3, KS-5
and so on.

Polyvinyl butyral resin is obtained as a derivative of PVA (polyvinyl alcohol), but the acetalization of the hydroxyl group of the original PVA is 80 mol at the maximum.
%, Usually from 50 mol% to 80 mol%
It is a degree. It should be noted that the acetal referred to here is 1 in a narrow sense.
It does not refer to the 1-diethoxyethane group, but refers to compounds in general with orthoaldehyde. The hydroxyl group is not particularly specified, but in the polymer constituting the outermost shell portion, the hydroxyl group-containing monomer is preferably 5 to 50 mol%, more preferably 10 to 30 mol%.
Is. The content of acetyl groups is not particularly limited, but is preferably 10 mol% or less. A polymer containing acetal as a main functional group means at least 30 mol% of oxygen atoms contained in the polymer.
The above means that an acetal group is formed.

Besides, as a polymer containing acetal as a main functional group, Iupital series manufactured by Mitsubishi Engineering Plastics Co., Ltd. and the like can also be used.

Examples of the polymer containing carbonic acid ester as a main functional group include polycarbonate resins. For example, there are Iupilon series and Novarex series manufactured by Mitsubishi Engineering Plastics Co., Ltd. The Iupilon series is made from bisphenol A as a raw material, and various molecular weights can be used although the value varies depending on the measuring method. The Novarex series has a molecular weight of 20,000 and a glass transition point of 150.
A material having a temperature in the vicinity of ° C can be used, but the material is not limited to these.

The polymer containing a carbonic acid ester group as a main functional group means that at least 30 mol% or more of oxygen atoms contained in the polymer contribute to the formation of a carbonic acid ester group.

Examples of the polymer having a hydroxyl group as a main functional group include PVA. Although the solubility of PVA in organic solvents is low in many cases, the solubility of PVA in organic solvents increases if the saponification value is low. Highly water-soluble PVA can also be used by adding it to the aqueous phase, removing the organic solvent, and adsorbing it to the polymer suspension.

Commercially available PVA can be used, for example, Kuraray's Poval PVA-102 and PVA.
VA-117, PVA-CSA, PVA-617, PV
In addition to A-505, special grade PVA for sizing agents,
As PVA for hot melt molding and other functional polymers, K
L-506, C-118, R-1130, M-205,
MP-203, HL-12E, SK-5102, etc. can be used. The degree of saponification is generally 50 mol% or more, but it is 40 mol as in LM-10HD.
Even if it is about 1%, it is possible to use it.
Other than PVA, those having a hydroxyl group as a main functional group can be used, but those having at least 20 mol% or more of oxygen atoms contained in the polymer forming a hydroxyl group can be used.

Examples of the polymer containing an ester group as a main functional group include methacrylic resin. Asahi Kasei Delpet series 560F, 60N,
80N, LP-1, SR8500, SR6500, etc. can be used. The polymer containing an ester group as a main functional group means that at least 30 mol% or more of oxygen atoms contained in the polymer form an ester group.

One of these polymers is used or two of them are used.
You may mix and use 1 or more types. Further, other polymers and inorganic fillers may be contained as long as these polymers are contained in a mass ratio of 50% or more.

Although it is preferable to use a copolymer of these polymers, for example, a polymer containing a hydroxyl group,
As a method of copolymerizing various polymers, it can be obtained by reacting a hydroxyl group with a monomer having an epoxy group such as glycidyl methacrylate and then copolymerizing it with a methacrylic acid ester monomer by suspension polymerization.

In the water-based ink of the present invention, the polymer used for the colored fine particles is 0.5 to 50 in the ink.
It is preferably blended in an amount of 0.5% by mass and 0.5 to 30% by mass.
It is more preferable that it is blended. If the blending amount of the above polymer is less than 0.5% by mass, the ability to protect the coloring material is insufficient, and if it exceeds 50% by mass, the storage stability of the suspension as an 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, it is preferably within the above range.

Next, the color material according to the present invention will be described. In the present invention, various dyes or pigments known in the ink jet can be used as the coloring material encapsulated by the polymer, but in the present invention, it is preferable to use a dye as the coloring material. The dye that can be used is not particularly limited, and examples thereof include oily dyes, disperse dyes, direct dyes, acid dyes, and basic dyes. In the present invention, it is preferable to use oily dyes.

As the hue, yellow, magenta, cyan, black, blue, green and red are preferably used, and yellow, magenta, cyan and black dyes are particularly preferable. The oil-soluble dyes also include dyes that exhibit oil-solubility by forming a salt of a water-soluble dye with a long-chain base. The oily dye is not limited to the following, but a particularly preferred specific example is, for example, Valifast manufactured by Orient Chemical Industry Co., Ltd.
Yellow 4120, Valifast Yel
low 3150, Valifast Yellow
3108, Valifast Yellow 2310
N, Valifast Yellow 1101, Va
liftast Red 3320, Valifast
Red 3304, Valifast Red 130
6, Valifast Blue 2610, Vali
fast Blue 2606, Valifast B
lue 1603, Oil Yellow GG-S,
Oil Yellow 3G, Oil Yellow 1
29, Oil Yellow107, Oil Yell
ow 105, Oil Scarlet 308, Oi
l Red RR, Oil Red OG, Oil R
ed 5B, OilPink 312, Oil Blu
e BOS, Oil Blue 613, Oil Bl
ue 2N, Oil Black BY, Oil Bl
ack BS, Oil Black 860, Oil
Black 5970, Oil Black 590
6, Oil Black 5905, Kayase Yellow SF-G, Kay manufactured by Nippon Kayaku Co., Ltd.
aset Yellow K-CL, Kayaset
Yellow GN, Kayaset Yellow
AG, Kayset Yellow 2G, Kay
asset Red SF-4G, Kayase Re
d K-BL, Kayaset Red A-BR, K
ayasetMagenta312, Kayaset
Blue K-FL, FS manufactured by Arimoto Chemical Industry Co., Ltd.
Yellow 1015, FS Magenta 14
04, FS Cyan 1522, FS Blue 1
504, C.I. I. Solvent Yellow 8
8 、 Solvent Yellow 83 、 Solve
nt Yellow 82, Solvent Yell
ow 79, Solvent Yellow 56, S
solvent Yellow 29, Solvent
Yellow 19, Solvent Yellow
16, Solvent Yellow 14, Solv
ent Yellow 04, Solvent Yel
low 03, Solvent Yellow 02,
Solvent Yellow 01, C.I. I. Sol
Vent Red 84: 1, C.I. I. Solvent
Red 84, C.I. I. SolventRed 21
8, C.I. I. Solvent Red 132, C.I.
I. Solvent Red 73, C.I. I. Solv
ent Red 72, C.I. I. Solvent Re
d 51, C.I. I. Solvent Red 43,
C. I. Solvent Red 27, C.I. I. So
lvent Red 24, Solvent Red
18, Solvent Red 01, Solvent
Blue 70, Solvent Blue 67, S
solvent Blue44, Solvent Blu
e 40, Solvent Blue 35, Solv
ent Blue 11, Solvent Blue
02, Solvent Blue 01, Solve
nt Black 43, C.I. I. Solvent B
rack 70, C.I. I. Solvent Black
34, C.I. I. Solvent Black 29,
C. I. Solvent Black 27, C.I. I.
Solvent Black 22, C.I. I. Solv
ent Black 7, C.I. I. Solvent B
rack 3, C.I. I. Solvent Violet
3, C.I. I. Solvent Green 3 and 7
Etc.

Further, JP-A-9-277693 and 10
Metal complex dyes as shown in Nos. -20559 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 Al, Co, Cr, Cu, Fe, Mn, Mo and N.
Examples include ions of i, Sn, Ti, Pt, Pd, Zr, and Zn. Ni, Cu, Cr, from the color tone and various durability,
Ions of Co, Zn and Fe are particularly preferable. More preferably, it is Ni ion.

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

The disperse dye is not limited to the following, but particularly preferable specific examples include C.I. I. Disperse Yellow 5, 42, 54, 64, 79, 8
2, 83, 93, 99, 100, 119, 122, 12
4, 126, 160, 184: 1, 186, 198, 1
99, 204, 224 and 237; C.I. I. Disperse Orange 13, 29, 31: 1, 33, 49, 54,
55, 66, 73, 118, 119 and 163;
I. Disperse Red 54, 60, 72, 73, 8
6, 88, 91, 92, 93, 111, 126, 12
7, 134, 135, 143, 145, 152, 15
3, 154, 159, 164, 167: 1, 177, 1
81, 204, 206, 207, 221, 239, 24
0, 258, 277, 278, 283, 311, 32
3, 343, 348, 356 and 362; I. Disperse Violet 33; C.I. I. Disperse Blue 56, 60, 73, 87, 113, 128, 143,
148, 154, 158, 165, 165: 1, 16
5: 2, 176, 183, 185, 197, 198, 2
01, 214, 224, 225, 257, 266, 26
7, 287, 354, 358, 365 and 368; and C.I. I. Examples include Disperse Green 6: 1 and 9.

Although the pigment is not limited to the following, as a particularly preferred specific example, the carbon black pigment may be No. No. 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 75, 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 151, 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 112, 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. The coloring material contained in the colored fine particles according to the present invention, such as Vat Blue 60, is 1 to 3 in the ink.
It is preferably blended in an amount of 0% 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 print density is insufficient, and if it exceeds 30% by mass, the stability of the suspension with time deteriorates.
Since the particle size tends to increase due to agglomeration and the like, it is preferably within the above range.

The ink jet ink of the present invention (hereinafter,
The ink of the present invention) is composed of a suspension of a polymer in which water is used as a medium and in which the above-mentioned coloring material is encapsulated. In the suspension, various conventionally known additives, for example, wetting agents such as polyhydric alcohols and dispersions are used. Agents, antifoaming agents such as silicone-based agents, antifungal agents such as chloromethylphenol-based agents and / or chelating agents such as EDTA, and oxygen absorbers such as sulfites may be contained.

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 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 ink.

The dispersant is not particularly limited, but when the HLB value is 8 to 18, the effect as the dispersant is exhibited and the effect of suppressing the increase in the particle diameter of the suspension is exerted. It is preferable from a certain point.

Commercially available products can also be used as the dispersant. Examples of such a commercially available product include dispersants DEMOL SNB, MS, N, SSL, ST, P manufactured by Kao Corporation.
(Product name).

The amount of the dispersant blended is not particularly limited, but 0.01 to 10% by mass is preferably blended in the ink of the present invention. If the compounding amount of the compound 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 is increased or the suspension stability is lowered to cause gelation. Therefore, it is preferable that the content is within the above range.

The antifoaming 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 in the colored fine particle-containing ink of the present invention, 0.0
It is preferably blended in an amount of 01 to 2% by mass. 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. ,
At the time of printing, repellency may occur in the ink and the print quality may deteriorate, so the range is preferably within the above range.

Next, the method for producing the ink of the present invention will be described. The ink of the present invention can be manufactured by various emulsification methods.

As described above, in the invention according to claim 4, the volume average particle diameter of the colored fine particles is preferably 10 to 150 nm, but there is no particular limitation as a method for achieving the average particle diameter defined above. However, it can be achieved, for example, by appropriately selecting or combining the types and amounts of the dispersants described above, or the emulsification methods shown below.

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 emulsifying / dispersing device using ultrasonic waves, high-speed rotary shearing, and high pressure.

Two types of so-called batch type and continuous type can be used for ultrasonic 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 required to be 3 seconds or longer, and if the emulsification is completed within that time, the ultrasonic wave emulsification dispersion device is not required. Further, if it is necessary for 10000 seconds or more, the load of the process is heavy, and it is necessary to shorten the emulsification / dispersion time by reselection of the emulsifier in practice. Therefore, 10,000 seconds or more is not necessary. More preferably, 10 seconds or more, 20
It is within 00 seconds.

Examples of the emulsification / dispersion device using high-speed rotary shear include a disper mixer as described on pages 255-256 of “Advancement of functional emulsifier / emulsification technology and its application development”, and 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. Since the clearance with the stator is usually about 0.5 mm and cannot be extremely narrowed, the shearing force mainly depends on the peripheral speed of the stirring blade. When the peripheral speed is 5 m / sec or more and 150 m / sec 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 / sec. More preferably, it is 20 to 100 m / sec.

For emulsification and dispersion under high pressure, LAB2000
(Made by SMT) can be used, but the emulsification /
Dispersion capacity depends on the pressure applied to the sample. The pressure is preferably 10 MPa or more and 500 MPa or less. In addition, the desired particle size can be obtained by emulsifying and dispersing several times as necessary. If the pressure is too low, the desired particle size cannot be achieved in many cases, no matter how many times emulsification and dispersion are performed, and in order to set the pressure to 500 MPa, a large load is applied to the device, which is not practical. More preferably, it is 50 MPa or more and 200 MPa or less.

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 by combining with the above-mentioned device, the effect of the present invention can be enhanced by enabling emulsification / dispersion in a single time. .

Further, the ink of the present invention can be produced by so-called phase inversion emulsification, in addition to using the above apparatus.

Here, in the phase inversion emulsification, the above-mentioned polymer is dissolved in an organic solvent such as ester or ketone together with the above-mentioned dye, a neutralizing agent is added as necessary to ionize the carboxyl group in the polymer, and then the After adding the aqueous phase, the organic solvent is distilled off to invert the phase to an aqueous system.

After completion of the phase inversion, the system is heated under reduced pressure to remove the ester and ketone solvents and a predetermined amount of water to obtain the colored fine particles of the present invention having a desired concentration. A water-based ink containing ink is obtained.

Next, another preferred embodiment of the ink jet ink of the present invention will be described.

In the eighth aspect of the present invention, the surface tension of the inkjet ink is preferably 25 or more and 50 mN / m or less, and more preferably 30 to 4
It is 0 mN / m. As a means for adjusting the surface tension of the inkjet ink of the present invention, it is preferable to use various surfactants and to appropriately adjust the type and the addition amount thereof.

According to the ninth aspect of the invention, the pH of the ink jet ink is preferably 6.0 or more and 11.0 or less, and more preferably 8.0 or more.
It is 0.0 or less. Examples of the pH adjuster used in the inkjet ink of the present invention include various organic amines such as monoethanolamine, diethanolamine and triethanolamine, and alkali metal hydroxides such as sodium hydroxide, lithium hydroxide and potassium hydroxide. Examples thereof include inorganic alkaline agents such as substances, organic acids, and mineral acids.

In the tenth aspect of the invention, the ink solvent content is preferably 10% by mass or more and 60% by mass or less, and more preferably 20 to 50% by mass.

The ink solvent used in the present invention is not particularly limited, but a water-soluble organic solvent is preferable, and specifically, alcohols (for example, methanol, ethanol, propanol, isopropanol, butanol, isobutanol,
Secondary butanol, tertiary butanol, pentanol, hexanol, cyclohexanol, benzyl alcohol, etc., polyhydric alcohols (eg, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene) Glycol, hexanediol, pentanediol, glycerin, hexanetriol, thiodiglycol, etc.), polyhydric alcohol ethers (eg ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monophenyl ether, diethylene glycol) Monomethyl ether, diethylene glycol Noethyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, triethylene glycol dimethyl ether , Dipropylene glycol monopropyl ether, tripropylene glycol dimethyl ether, etc.),
Amines (for example, ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, morpholine,
N-ethylmorpholine, ethylenediamine, diethylenediamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine, pentamethyldiethylenetriamine, tetramethylpropylenediamine, etc.),
Amides (eg, formamide, N, N-dimethylformamide, N, N-dimethylacetamide, etc.), heterocycles (eg, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, 2 -Oxazolidone, 1,3-dimethyl-2-imidazolidinone etc.), sulfoxides (eg dimethyl sulfoxide etc.), sulfones (eg sulfolane etc.), sulfonates (eg 1-butanesulfonic acid sodium salt etc.) , Urea, acetonitrile, acetone and the like.

In the ink-jet ink of the present invention, one kind or two or more kinds of anionic surfactant, nonionic surfactant and cationic surfactant can be used. Each surfactant that can be used in the present invention is not particularly limited, but examples thereof include anionic surfactants such as dialkylsulfosuccinates, alkylnaphthalenesulfonates, fatty acid salts, polyoxyethylene alkyl ethers, and polyoxyethylene alkyl ethers. Examples thereof include nonionic surfactants such as oxyethylene alkyl allyl ethers, acetylene glycols, polyoxyethylene / polyoxypropylene block copolymers, and cationic surfactants such as alkylamine salts and quaternary ammonium salts. In particular, an anionic surfactant and a nonionic surfactant can be preferably used.

Further, in the present invention, a polymeric surfactant can also be used, and examples thereof include styrene-acrylic acid-alkyl acrylate copolymer, styrene-acrylic acid copolymer, styrene-maleic acid-acrylic. Acid alkyl ester copolymer, styrene-maleic acid copolymer, styrene-methacrylic acid-acrylic acid alkyl ester copolymer, styrene-methacrylic acid copolymer, styrene-maleic acid half ester copolymer, vinylnaphthalene-acrylic Examples thereof include acid copolymers and vinylnaphthalene-maleic acid copolymers.

The ink-jet ink of the present invention may contain a water-soluble polymer or water-insoluble polymer dispersion.

A natural polymer is a preferred example of the water-soluble polymer, and specific examples thereof include glue and
Proteins such as gelatin, casein, or albumin, natural gums such as gum arabic, or gum tragacanth, glucosides such as savonine, alginic acid and propylene glycol alginate, triethanolamine alginate, or alginate derivatives such as ammonium alginate, methylcellulose, Examples thereof include cellulose derivatives such as carboxymethyl cellulose, hydroxyethyl cellulose, or ethyl hydroxyl cellulose.

Further, as a preferable example of the water-soluble polymer, a synthetic polymer can be mentioned, and polyvinyl alcohols, polyvinyl pyrrolidones, polyacrylic acid, acrylic acid-acrylonitrile copolymer, potassium acrylate-acrylonitrile copolymer. Acrylic resins such as vinyl acetate-acrylic acid ester copolymers or acrylic acid-acrylic acid ester copolymers, styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, styrene-methacrylic acid-acrylic acid Ester copolymer, styrene-
Styrene acrylic acid resin such as α-methylstyrene-acrylic acid copolymer or styrene-α-methylstyrene-acrylic acid-acrylic acid ester copolymer, styrene-maleic acid copolymer, styrene-maleic anhydride copolymer Copolymer, vinylnaphthalene-acrylic acid copolymer, vinylnaphthalene-maleic acid copolymer, and vinyl acetate-ethylene copolymer, vinyl acetate-fatty acid vinylethylene copolymer, vinyl acetate-maleic acid ester copolymer, acetic acid Examples thereof include vinyl acetate-based copolymers such as vinyl-crotonic acid copolymers and vinyl acetate-acrylic acid copolymers and salts thereof. Among these, polyvinylpyrrolidones are particularly preferable.

The molecular weight of the water-soluble polymer is preferably 1,000 or more and 200,000 or less. Furthermore, 3,000 or more and 20,000 or less are more preferable. If it is less than 1,000, the effect of suppressing the growth and aggregation of the colored fine particles is reduced, and if it exceeds 200,000, problems such as an increase in viscosity and poor dissolution tend to occur.

The amount of the water-soluble polymer added is 1 with respect to the dye.
It is preferably 0% by mass or more and 1,000% by mass or less. Furthermore, 50 mass% or more and 200 mass% or less are more preferable.
If it is less than 10% by mass, the effect of suppressing the growth and aggregation of the colored fine particles is reduced, and if it exceeds 1000% by mass, problems such as viscosity increase and poor dissolution tend to occur.

Further, as a water-insoluble polymer dispersion liquid (hereinafter also referred to as latex) which can be used in the present invention,
Although not particularly limited, for example, styrene-butadiene copolymer, polystyrene, acrylonitrile-butadiene copolymer, acrylic ester copolymer, polyurethane,
Examples thereof include silicone-acrylic copolymers and latices such as acrylic modified fluorinated grease. Latex, even if the polymer particles are dispersed using an emulsifier,
It may also be dispersed without using an emulsifier. A surfactant is often used as an emulsifier, but a polymer having a water-soluble group such as a sulfonic acid group or a carboxylic acid group (for example, a polymer having a solubilizing group graft-bonded thereto or a monomer having a solubilizing group It is also preferable to use a polymer obtained from a monomer and a monomer having an insoluble portion.

It is particularly preferable to use soap-free latex in the ink of the present invention. Soap-free latex is a latex that does not use an emulsifier, and a polymer having a water-soluble group such as a sulfonic acid group and a carboxylic acid group (for example, a polymer having a solubilizing group graft-bonded thereto, a solubilizing group Polymer obtained from a monomer having an insoluble portion and a monomer having an insoluble portion) is used as an emulsifier.

In recent years, as latex polymer particles, in addition to a latex in which polymer particles having a uniform particle size are dispersed, a core having a different composition in the central portion and the outer edge portion
Although there is a latex in which shell-type polymer particles are dispersed, this type of latex can also be preferably used.

In the ink of the present invention, the average particle size of the polymer particles in the latex is 10 nm or more and 300 nm or less, and more preferably 10 nm or more and 100 nm or less. If the average particle size of the latex exceeds 300 nm, the glossiness of the image deteriorates, and if it is less than 10 nm, the water resistance and scratch resistance become insufficient. The average particle size of the polymer particles in the latex can be determined by a commercially available particle size measuring device using a light scattering method, an electrophoresis method, or a laser Doppler method.

In the ink of the present invention, the latex is 0.1% by mass based on the total mass of the ink as a solid content.
As described above, it is added so as to be 20% by mass or less, but it is particularly preferable that the solid content of the latex is 0.5% by mass or more and 10% by mass or less. If the solid content of the latex is less than 0.1% by mass, it is difficult to exert a sufficient effect on water resistance, and if it exceeds 20% by mass, the viscosity of the ink increases with the passage of time and the dispersion of colored fine particles occurs. In many cases, problems occur in terms of ink storability such that the particle size tends to increase.

In the ink of the present invention, in addition to the above description, the emission stability, print head or ink cartridge compatibility, storage stability, image storability, and other various performance improving objectives may be used as necessary. , Various known additives, for example, viscosity modifier, resistivity modifier, film-forming agent, ultraviolet absorber, antioxidant, anti-fading agent, anti-rust agent, rust inhibitor, etc. may be appropriately selected and used. For example, liquid paraffin, dioctyl phthalate, tricresyl phosphate, oil droplet fine particles such as silicone oil, and JP-A-57-74.
193, 57-87988 and 62-2614.
UV absorbers described in JP-A-76-74192.
No. 57-89789, No. 60-72785, No. 61-146591, No. 1-95091 and No. 3-13376, and anti-fading agents, No. 59-42993, 59-52689, 62
Examples thereof include fluorescent whitening agents described in JP-A-280069, JP-A-61-242871 and JP-A-4-219266.

The recording medium used in the present invention includes plain paper, coated paper, swelling type inkjet recording paper provided with an ink receiving layer which absorbs and swells an ink liquid, and voids having a porous ink receiving layer. Type inkjet recording paper,
A substrate using a resin support such as a polyethylene terephthalate film may be used in place of the base paper. As the recording medium, in the invention according to claim 12, a void type porous inkjet recording medium is used. Preferably, this combination can maximize the effects of the present invention.

As the porous ink jet recording medium,
Specifically, mention may be made of void-type inkjet recording paper or void-type inkjet film, which are recording media provided with a void layer having an ink absorbing ability, and the void layer is mainly hydrophilic. It is formed by soft agglomeration of the binder and the inorganic fine particles.

Various methods of forming a void layer are known as a method of forming voids in a film. For example, a uniform coating solution containing two or more kinds of polymers is coated on a support and dried. A method of phase-separating these polymers with each other to form voids, a coating liquid containing solid fine particles and a hydrophilic or hydrophobic binder is applied on a support, and after drying,
A method of immersing an inkjet recording paper in water or a liquid containing a suitable organic solvent to dissolve solid fine particles to form voids, a coating liquid containing a compound having a property of foaming during film formation, and a drying process. A method of foaming this compound to form voids in the film, a method of applying a coating liquid containing porous solid fine particles and a hydrophilic binder onto a support to form voids in the porous fine particles or between the fine particles. ,
A method of forming voids between solid fine particles by applying a coating liquid containing solid fine particles and / or fine particle oil droplets and a hydrophilic binder having a volume equal to or more than the hydrophilic binder to a solid fine particle. However, when using the ink of the present invention, good results are obtained even if they are provided by any method.

The inkjet head that can be used in the inkjet image forming method of the present invention may be either an on-demand system or a continuous system.
In addition, as a discharge method, an electro-mechanical conversion method (for example, a single cavity type, a double cavity type,
Bender type, piston type, shear mode type, shared wall type, etc., electric-heat conversion method (for example, thermal ink jet type, bubble jet (R) type, etc.), electrostatic attraction method (for example, electric field control type, slit jet) Type) and a discharge method (for example, a spark jet type) can be given as specific examples, but any discharge method may be used.

[0104]

The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

Example 1 << Synthesis of Colored Fine Particles >> Colored Fine Particles 1 to 14 shown in Table 1
Was prepared. An example of the synthesis is shown below.

<Preparation Example 1: Preparation of colored fine particle dispersion 1>
5.0g polyvinyl butyral (Sekisui Chemical's BL-
S, average degree of polymerization 350), 5.0 g of cyan dye (C.I.
I. Solvent Blue 70) and 50 g of ethyl acetate were placed in a separable flask, the inside of the flask was replaced with nitrogen gas, and the mixture was stirred to give the polyvinyl butyral and C.I. I. Solvent Blue 70 was completely dissolved.
Then, 100 g of an aqueous solution containing 2.0 g of sodium dodecyl sulfonate was added dropwise, stirred, and then emulsified for 300 seconds using an ultrasonic disperser (UH-150 type, SMT Co., Ltd.). Then, ethyl acetate was removed under reduced pressure to obtain a core type colored fine particle dispersion impregnated with the dye.

Next, in the shell forming step, the inside of the flask containing the above dispersion was replaced with nitrogen gas, and then 0.15 g of potassium persulfate was added to the dispersion to dissolve it.
After heating with a heater to 70 ℃, styrene /
Core-shell type colored fine particles containing a cyan dye, after reacting for 7 hours while dropping 2 g of a mixed liquid of 2-hydroxyethyl methacrylate (molar ratio 4/1) to form a shell and then purifying with an ultrafiltration device. Dispersion 1 was obtained. The average particle diameter of the colored fine particles contained in this colored fine particle dispersion 1 was 83 nm.

<Preparation Example 2: Preparation of colored fine particle dispersion 5>
5.0g polyvinyl butyral (Sekisui Chemical's BL-
S, average degree of polymerization 350), 5.0 g of dye 1 and 50 g
The ethyl acetate of was added to a separable flask, the inside of the flask was replaced with nitrogen gas, and the mixture was stirred to completely dissolve the polyvinyl butyral and the dye 1. Then, 90 g of an aqueous solution containing 2.0 g of Aqualon KH-10 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was added dropwise and stirred, and then an ultrasonic disperser (UH-1).
50 type manufactured by SMT Co., Ltd.) was used to emulsify for 300 seconds. Then, ethyl acetate was removed under reduced pressure to obtain a core type colored fine particle dispersion impregnated with the dye.

Then, in the shell forming step, the inside of the flask containing the above dispersion was replaced with nitrogen gas, and then 0.1 g of potassium persulfate was added to the dispersion to dissolve it, and the mixture was heated to 70 After heating to 0 ° C, 3 g of a mixture of styrene / polyethylene glycol methacrylate (average number of addition units: 4) (molar ratio 5/1) was added dropwise to the mixture to react for 7 hours to form a shell, followed by ultrafiltration. Purification by an apparatus gave a core-shell type colored fine particle dispersion 5 containing a cyan dye. The average particle diameter of the colored fine particles contained in this colored fine particle dispersion 5 was 86 nm.

Preparation Example 3: Preparation of Colored Fine Particle Dispersion 10 5.0 g of cyan dye (CI Solvent)
Blue 70), 50 g of ethyl acetate, 5 g of butyl methacrylate / dodecyl methacrylate copolymer (molar ratio 75/25) and 2 g of styrene / methacrylic acid (molar ratio 4/1) were placed in a separable flask, and C.I. I. Solvent Blue 70 was completely dissolved. Then, after diethanolamine was added to the solution to neutralize it, the mixture was emulsified for 300 seconds using an ultrasonic disperser (UH-150 type, SMT Co., Ltd.). Then, after removing ethyl acetate under reduced pressure, the product was purified by an ultrafiltration device to obtain a colored fine particle dispersion 10 containing a cyan dye. The average particle size of the colored fine particles contained in the colored fine particle dispersion 10 is 103
was nm.

Preparation Example 4: Preparation of Colored Fine Particle Dispersion 12: Comparative Example 5.0 g of Dye 1, 50 g of ethyl acetate and 5 g of styrene / butyl methacrylate / 2-hydroxyethyl methacrylate / polyethylene glycol methacrylate (average addition) The number of units: 4) / methacrylic acid (molar ratio 60/25/5/5/5) was placed in a separable flask and mixed to completely dissolve dye 1. Next, this liquid was emulsified for 300 seconds using an ultrasonic disperser (UH-150 type, SMT Co., Ltd.). Then, ethyl acetate was removed under reduced pressure, and then diethanolamine was added to the solution for neutralization, followed by purification with an ultrafiltration device to obtain a colored fine particle dispersion 12 containing Dye 1. The average particle diameter of the colored fine particles contained in this colored fine particle dispersion 12 was 78 nm.

<Preparation of Other Colored Fine Particles> For the colored fine particle dispersions other than those described above, the types of coloring materials, core polymers, surfactants and shell polymers shown in Table 1 were used and the same as in the above synthesis example. Was synthesized.

[0113]

[Chemical 1]

<< Measurement of Characteristic Value of Colored Fine Particle Dispersion >> (Measurement of Average Particle Size of Each Colored Fine Particle) Each colored fine particle dispersion was diluted 1000 times with 0.1% aqueous solution of Perex OT-P, The average particle size (volume average particle size) was measured using a laser particle size analysis system manufactured by Otsuka Electronics.

(Determination of Surface Polar Group Amount of Colored Fine Particles) A known amount of each colored fine particle dispersion was diluted with water, an appropriate amount of poly (diallyldimethyl-ammonium chloride) solution was added, and toluidine blue solution was used as an indicator. After the addition, colloid titration was performed with a polyvinyl potassium sulfate solution, and the amount of surface polar groups (μmol / g) was measured. The number of polar groups per 1 nm ² of surface area of the colored fine particles specified in the present invention is 10 by multiplying the above-mentioned measured amount of surface polar groups (μmol / g) by the volume-average particle diameter (nm) measured above.
It was calculated by dividing by 000.

(Measurement of Ratio of Surface Polar Group Amount to Total Polar Group Amount of Colored Fine Particles) Dilute hydrochloric acid was added to a known amount of the colored fine particle dispersion, ultrasonic dispersion treatment and centrifugal separation treatment were repeated, and then the mixture was treated with ultrapure water. Washing and drying are performed to prepare a colored fine particle powder in which the polar group is in an acid form, a certain amount of sodium hydroxide is added to the colored fine particle powder, and neutralization titration is performed with hydrochloric acid to determine the total amount of the polar group ( μmol / g) was calculated.

Next, the total amount of polar groups measured here (μm
ol / g), the amount of surface polar group measured above (μmo
The ratio of 1 / g) was calculated.

Table 1 shows the evaluation results of the respective characteristic values obtained above and the constitutions of the respective colored fine particle dispersions.

[0119]

[Table 1]

Details of the compound abbreviations shown in Table 1 are as follows. P-1: Styrene / butyl acrylate / acrylic acid /
2-hydroxyethyl acrylate = 60/20/5 /
15 (molar ratio) P-2: styrene / butyl acrylate / acrylic acid =
65/30/5 P-3: butyl acrylate / dodecyl methacrylate = 75/25 P-4: styrene / butyl methacrylate / 2-hydroxyethyl methacrylate / polyethylene glycol methacrylate = 60/30/5/5 P-5: styrene / Butyl methacrylate / 2-hydroxyethyl methacrylate / polyethylene glycol methacrylate / methacrylic acid = 60/25/5/5/5 P-6: butyl acrylate / dodecyl methacrylate / acrylic acid = 75/20/5 P-7: N-butoxy Methyl acrylamide P-8: Styrene / 2-hydroxyethyl acrylate = 4/1 P-9: Styrene / polyethylene glycol methacrylate = 5/1 P-10: John Kryl 52 (manufactured by Johnson Polymer Co.) P-11: Su Len / 2-hydroxyethyl acrylate / acrylic acid = 8/2/1 P-12: 2-hydroxyethyl acrylate M-1: styrene / methacrylic acid = 4/1 SA-1: sodium dodecyl sulfonate SA-2: aqualone KH-10 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) << Preparation of Ink >> Inks 1 to 22 were prepared using the colored fine particle dispersions prepared above. In the preparation of each ink, pure water, the ink solvent shown in Table 2 and a surfactant were added to each colored fine particle dispersion, and the concentration of the coloring material in the ink was appropriately adjusted to 2% by mass. The pH was adjusted to the values shown in Table 2 by using an aqueous solution of sodium hydroxide or an aqueous solution of acetic acid, and adjusting the surface tension by adjusting the amount of the surfactant added. 2 of each ink prepared as described above
Inks 1 to 22 shown in Table 2 were prepared by filtering with a μm membrane filter to remove dust and coarse particles.

Details of each compound shown in Table 2 are as follows. Solvent 1: ethylene glycol / glycerin = 18/10
(Mass ratio) Solvent 2: ethylene glycol / glycerin / triethylene glycol monobutyl ether = 10/10/8 (mass ratio) SA-3: Surfynol 465 (manufactured by Nisshin Chemical Industry Co., Ltd.) SA-4: Olphin E1010 (day) Nonionic surfactant manufactured by Shinka Chemical Co., Ltd. <Measurement of pH and surface tension> The pH and surface tension were measured by a conventional method.

<Evaluation of Storability of Ink> Each of the above-prepared inks was placed in a container, sealed, and stored at 60 ° C. for 7 days, and the average particle diameter of the colored fine particles and the ink liquid were visually observed. The ink storability was evaluated in accordance with the standard.

5: The change rate of the average particle size is less than 5%, and no aggregated precipitate is observed. 4: The change rate of the average particle size is 5 to less than 10%, and almost no aggregated precipitate is observed. 3: The change rate of the average particle diameter is 10 to less than 15%, and a small amount of the aggregated precipitate is observed. 2: The change rate of the average particle size is 15 to less than 20%, the aggregated particle is observed. 1: The average particle Inkjet image formation and evaluation, in which the rate of change in diameter is 20% or more and the particles are considerably aggregated and settled (Image formation) (Ink formation) After storing each ink prepared above in an inkjet cartridge, a color inkjet printer PM-800 ( An image was created by printing on Konica Photo Jet Paper Photolike QP glossy paper (manufactured by Konica) by Epson. The output image was printed according to the following evaluation method.

(Evaluation of Image Bleeding Resistance) Prior to printing with the above ink, the solvent used in the preparation of each ink was uniformly ejected onto a recording medium with a color ink jet printer PM-800, and then the width of 0. A 3 mm line drawing was printed, and the image blur resistance was evaluated according to the following evaluation criteria.

5: No change is observed in the printed line image 4: Slight bleeding is recognized in the printed line image 3: Bleeding is recognized in the printed line image, which is a practically acceptable level 2: Printing The line drawing has obvious blurring and the image is disturbed and exceeds the permissible level. 1: The printed line drawing has significant blurring and the image is disturbed to an unidentifiable degree (evaluation of light resistance). Output density 0% to 1
Wedge image (3 cm) divided into 16 steps from 00%
X3 cm patch-like image), using a patch with a reflection density of about 1.0, in a xenon fade meter 70,
After irradiation with 000lux of xenon light for 300 hours, the residual ratio of reflection density {(reflection density after irradiation of xenon light) ÷
(Reflection density before xenon light irradiation) × 100 (%)} was calculated. Based on this residual rate, evaluation was made according to the following criteria.

5: Remaining reflection density is 90% or more 4: Reflection density residual rate is 80% or more and less than 90% 3: Remaining reflection density is 70% or more and less than 80% 2: Reflection density residual rate is 50% or more and less than 70% 1: Remaining reflection density is less than 50% Table 2 shows the evaluation results obtained as described above.

[0127]

[Table 2]

As is clear from Table 2, the comparative examples were evaluated as inferior in terms of ink storage stability, image bleeding resistance, and light resistance. On the other hand, each of the samples of the present invention has good ink storability in all of the samples, and also has excellent properties in both image blur resistance and light resistance of the printed image. . Further, by setting the surface tension to 25 to 50 mN / m, setting the pH to the range of 6.0 to 11.0, and setting the ink solvent content to 10 to 60% by mass,
It was confirmed that the effect was further enhanced.

[0129]

According to the present invention, it is possible to provide a colored fine particle dispersion, an ink jet ink and an ink jet image forming method which are excellent in ink storability and have improved image bleeding resistance and light resistance of the formed image. .

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09D 17/00 B41J 3/04 101Y F term (reference) 2C056 EA13 FC01 2H086 BA55 BA59 BA60 BA62 4J037 AA30 DD05 FF22 FF23 4J039 BE01 CA06 EA35 EA44 EA47 GA24

Claims (12)

[Claims] 1. At least one kind selected from colored fine particles made of a resin containing a colorant, colored fine particles made of a resin coated with a colorant, and colored fine particles having a surface of a resin containing a colorant further coated with a resin. In the colored fine particle dispersion containing colored fine particles, the number of non-eliminating surface polar groups at pH 9 of the colored fine particles is 0.2 to 1 per nm ^2.
A colored fine particle dispersion comprising three particles. 2. At least one kind selected from colored fine particles made of a resin containing a colorant, colored fine particles made of a resin coated with a colorant, and colored fine particles having a surface of a resin containing a colorant further coated with a resin. A colored fine particle dispersion containing colored fine particles, wherein the colored fine particles have a non-eliminating amount of surface polar groups at pH 9 of 50% or more of the total amount of polar groups. 3. At least one selected from coloring fine particles made of a resin containing a coloring material, coloring fine particles made of a resin coating a coloring material, and coloring fine particles made by further coating the surface of a resin containing a coloring material with a resin. In the colored fine particle dispersion containing colored fine particles, the number of non-eliminating surface polar groups at pH 9 of the colored fine particles is 0.2 to 1 per nm ^2.
The colored fine particle dispersion according to claim 2, wherein the number is three. 4. The volume average particle diameter of the colored fine particles is 1
It is 0-150 nm, The colored fine particle dispersion of any one of Claims 1-3 characterized by the above-mentioned. 5. The colored fine particle dispersion according to claim 1, wherein the colored fine particles have a core-shell structure in which the surface of a resin containing a coloring material is further covered with the resin. . 6. The colored fine particle dispersion according to claim 1, wherein the colored fine particles have a core-shell structure in which the surface of a resin containing a dye is further coated with the resin. 7. The ink according to claim 1, wherein at least one color ink is used.
7. An inkjet ink containing the colored fine particle dispersion according to any one of 6 above. 8. The inkjet ink according to claim 7, which has a surface tension of 25 or more and 50 mN / m or less. 9. The inkjet ink according to claim 7, which has a pH of 6.0 or more and 11.0 or less. 10. The inkjet ink according to claim 7, wherein the ink solvent content is 10% by mass or more and 60% by mass or less. 11. An inkjet image forming method, comprising forming an image using at least one inkjet ink according to claim 7. 12. An inkjet image forming method, which comprises forming an image on a void type porous inkjet recording medium using at least one inkjet ink according to any one of claims 7 to 10. .