JP2003253180A - Recording liquid for inkjet and method for manufacturing it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide recording liquid for inkjet in which a dye and a red pig ment are used and which is excellent in dispersibility and has good printability and storage stability, and a method for manufacturing it. <P>SOLUTION: The recording liquid for inkjet comprising the red pigment, the dye and a surfactant in an aqueous medium, is characterized by (1) the red pigment and the dye comprising at least a part wherein the dye is reversibly adsorbed on the red pigment without being accompanied with chemical reaction, (2) the dye reversibly adsorbed on the red pigment without being accompanied with chemical reaction comprising the dye of an amount of dye adsorption of at least 0.02 g/g, wherein the amount of dye adsorption is expressed by equation (I): (amount of dye adsorption (g/g))=(ratio of dye adsorption in dispersion)×(total amount of dye in dispersion (0.4 g))/(amount of pigment in dispersion (4.1 g)), and (3) a nonionic surfactant and an anionic surfactant coexisting as the surfactant, and the method for manufacturing the recording liquid for inkjet is provided. <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 inkjet recording liquid which is preferably used for inkjet recording and a method for producing the same. Specifically, the present invention has excellent dispersibility,
The present invention relates to an inkjet recording liquid having good printability and storage stability, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, inks mainly used for water-soluble dyes and liquid media have been mainly used as inks for ink-jet recording. Light resistance and ozone resistance were insufficient. Therefore, an ink in which a pigment is dispersed in an aqueous medium instead of the dye has been developed. However, in such a pigment ink, a dispersant or a dispersion resin is often used in order to generally disperse the pigment in the ink. The most widely used polymeric dispersant increases the viscosity of the ink when it is added in a large amount, making it impossible to print with a recording method such as ink jet, while when the amount added is too small, the dispersibility of the pigment decreases. Aggregation and precipitation of pigment occur,
Since there is a potential problem of deterioration of storage stability of ink, improvement to an inkjet recording liquid that can be easily handled is desired.

On the other hand, pigments and dyes used in a recording liquid in which pigments and dyes are used in combination, 1) the pigments and the dyes are chemically adsorbed by reacting the functional groups on the pigment surface with the dyes. (See Patent Document 1) or 2) those in which a pigment and a dye are physically adsorbed (see Patent Documents 2, 3, 4, 5 and 6). Among them, in the former case, the kind of the dye to be adsorbed is limited by the kind of the functional group of the pigment used, and the combination of the dye and the pigment is restricted. For example, from the viewpoint of chemical reaction, it is necessary to combine a dye having an acidic group when the pigment surface has a basic functional group and a dye having a basic group when the pigment surface has an acidic functional group. However, since the aqueous recording liquid for inkjet is usually a basic medium, the use of a dye having an acidic group is selected in consideration of dispersibility in the medium. Therefore, there arises a problem that a pigment having a general acidic functional group such as a carboxyl group or a sulfone group cannot be used. Further, in this method, when the adsorption by the chemical reaction proceeds 100%, the effect of dispersion stability is exerted only by the functional groups remaining in the dye, but in reality, only the functional groups remaining in the dye are effective. In order to obtain stable dispersion stability, it is necessary to set the density of the functional group on the surface of the pigment on which the dye is to be adsorbed to a certain level or more. However, in this case, the adsorption does not proceed 100% due to the problem of steric hindrance between the dyes, and the pigment-derived functional group and the dye-derived group coexist on the surface of the dispersion particles. Becomes Since this state causes dispersion instability of individual particles or particle association, it cannot be said to be optimal as a dispersion for inkjet ink which requires long-term storage stability.

On the other hand, in the latter, the pigment and the water-soluble dye are used in combination with a polymer dispersant having a molecular weight of 1,000 to 100,000 in order to improve the water resistance and light resistance of the dye and the insufficient saturation of the pigment. A water-based recording liquid (for example, see Patent Document 2), a recording liquid including a dye having a sulfonic acid group or a sulfonate group, a liquid medium, a polymer material soluble in a liquid medium, and a pigment (see Patent Document 3), and An inkjet recording liquid containing a dye, a pigment, a water-soluble surfactant, and water is known (see, for example, Patent Document 4). However, the preparation of the pigment- and dye-containing dispersions in these known documents is carried out by mixing the pigment and the dye together with a polymer dispersant or a polymer material, or by dispersing the pigment in advance using a surfactant. It is carried out by mixing a dye with a liquid, and in such a preparation method, a dispersing effect due to adsorption of a dispersant such as a polymer dispersant or a surfactant on a pigment and a color tone due to the coexistence of a water-soluble dye Only the improvement effect of is obtained. Therefore, the adsorption state of the dye to the pigment, the control thereof, and the technical effect obtained thereby are not recognized or suggested. Further, in the case of a pigment dispersion liquid obtained by simply mixing a pigment, a dye and a polymer dispersant or a polymer material, a composite of the pigment and the polymer dispersant or the polymer material, a dye and a polymer dispersant or a polymer. The formation of a complex of materials will proceed at the same time, and the resulting inhomogeneity in the system may cause problems in reproducibility and aging with respect to solution properties of the dispersion liquid and the recording liquid, particularly viscosity properties. In addition, as the polymer dispersant described in Patent Document 2, a high molecular weight dispersant having a weight average molecular weight of 20,000 is used, and the problems that occur in the system using the polymer dispersant pointed out above are solved. You cannot do it.

Among the latter, a recording liquid (see Patent Documents 5 and 6) using a dye as a pigment dispersant instead of a surfactant or a polymer which is conventionally used for dispersing a pigment. However, when a recording liquid is prepared with a pigment dispersion that uses only a dye as a dispersant, the dispersion stability of the pigment is greatly reduced depending on the organic solvent and additives used. There is a large limitation on the organic solvent and additives used, and there is a problem in practicality. In particular, the method of Patent Document 6 requires that only a dye having the same basic skeleton as the pigment is used, and a step of removing unadsorbed dye from the dispersion of the pigment and the dye by ultrafiltration or centrifugation. Therefore, there is a problem in practicality in terms of the degree of freedom in color tone selection, complexity, cost, and the like.

[Patent Document 1] Japanese Patent Laid-Open No. 9-151344

[Patent Document 2] Japanese Patent Publication No. 60-45667

[Patent Document 3] Japanese Unexamined Patent Publication No. 5-247391

[Patent Document 4] JP-A-8-218019

[Patent Document 5] W / O 99/61534 pamphlet

[Patent Document 6] Japanese Patent Laid-Open No. 2000-273383

[0006]

Means for Solving the Problems As a result of intensive investigations in view of such circumstances, the present inventors have selected a combination of a red pigment and a dye having a specific physical adsorption property to the red pigment,
Furthermore, by using a combination of a nonionic surfactant and an anionic surfactant, good dispersibility, and
It was found that an inkjet recording liquid having good printability and storage stability can be obtained. Such a recording liquid can be simply obtained by first dispersing a pigment and a dye in an aqueous medium and then performing a secondary dispersion treatment in the presence of a surfactant. Is what is done. This is because the dye is first stably adsorbed on the surface of the pigment to obtain the effect of dispersing the pigment by the dye, and part of the adsorbed dye is partially absorbed by a specific surfactant suitable for the liquid of the recording liquid. By substituting, the secondary aggregation of the dispersion in the recording liquid can be suppressed, and the recording liquid can have excellent stability such as dispersibility, and the present invention has been achieved based on such findings. It is a thing.

The gist of the present invention is an ink jet recording liquid containing a red pigment, a dye and a surfactant in an aqueous medium, wherein 1) the red pigment and the dye are at least partially formed into the red pigment. The dye includes those which are reversibly adsorbed without a chemical reaction, and 2) the dye which is reversibly adsorbed to a red pigment without a chemical reaction is represented by the following formula (I). Including dyes having an adsorbed amount of 0.02 g / g or more,

[Equation 2] (Here, the dye adsorption rate is the supernatant liquid after removing solids from a dispersion liquid prepared using the above red pigment (4.1 g) and the above dye (0.4 g) in the absence of a surfactant. ,
And a value obtained from the ratio of the peak areas obtained by measuring the dye concentration of the dye (0.4 g) in an aqueous solution by high performance liquid chromatography. ),as well as,
3) In the inkjet recording liquid, a nonionic surfactant and an anionic surfactant coexist as the surfactant. Another aspect of the present invention is to mix a red pigment, a dye and / or a dye aqueous medium solution, and an aqueous medium to perform a primary dispersion treatment of the red pigment and the dye. A secondary dispersion treatment is carried out by adding a surfactant and an anionic surfactant and / or an aqueous medium solution of these surfactants, and the dye is reversibly adsorbed without a chemical reaction. And a nonionic surfactant and an anionic surfactant coexist as surfactants in the method for producing an inkjet recording liquid.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below. The ink jet recording liquid of the present invention contains a red pigment, a dye and a surfactant in an aqueous medium. 1) The red pigment and the dye are chemically reacted with at least a part of the red pigment and the dye. 2) a dye that is reversibly adsorbed to a red pigment without a chemical reaction, which is a dye adsorbed by a dye represented by the following formula (I). Including the amount of 0.02g / g or more,

[Equation 3] (Here, the dye adsorption rate is the supernatant liquid after removing solids from a dispersion liquid prepared using the above red pigment (4.1 g) and the above dye (0.4 g) in the absence of a surfactant. ,
And a value obtained from the ratio of the peak areas obtained by measuring the dye concentration of the dye (0.4 g) in an aqueous solution by high performance liquid chromatography. ),as well as,
3) As the surfactant, a nonionic surfactant and an anionic surfactant coexist.

The reversibly adsorbing the dye to the red pigment without a chemical reaction, which is the characteristic of the above 1), means that the dye is not adsorbed irreversibly by a chemical reaction such as a covalent bond but is physically adsorbed. It means reversibly adsorbing as exemplified by hydrogen bond and the like, and the selection of the red pigment and the dye requires a combination that produces such an adsorbed state. The fact that the dye is reversibly adsorbed to the pigment without involving a chemical reaction can be confirmed, for example, as follows. That is, dimethylformamide (DMF) was added to the prepared recording liquid in a large excess (for example, about 9 times by weight), thoroughly mixed by ultrasonic dispersion treatment, etc., and the filtrate was filtered to remove the pigment. Measure the amount of dye in it. By confirming in advance the amount of dye not adsorbed to the pigment in the recording liquid at the time of preparation, and by confirming the increased amount of the dye contained in the recording liquid after the treatment,
It can be confirmed that the dye is reversibly adsorbed on the pigment. Here, in the recording liquid of the present invention, as long as it does not adversely affect its performance, in addition to the pigment in which the dye is reversibly adsorbed without a chemical reaction, for example, self-dispersion performance by surface treatment or the like. Although it may contain a pigment having,
The content is usually 30% by weight or less, preferably 20% by weight or less, more preferably 10% by weight or less, further preferably 5% by weight or less, particularly preferably 1% by weight or less, based on the total amount of pigments. is there.

The characteristic of 2) above indicates that it is preferable to select and use a dye having a high adsorbability of the dye for the red pigment, as the dye to be adsorbed on the red pigment.
Dye adsorption amount with respect to the pigment represented by the formula (I) (hereinafter,
"Dye adsorption amount") is 0.02 g / g or more. Here, the "dye adsorption rate" in the formula (I) is a value obtained by the following method.

Dye adsorption rate: At 23 ° C., water was added to 4.1 g of the red pigment in a solid content and 0.4 g of the dye in a solid content to make the total amount to 50 g, and 75 g of 0.5 mmφ zirconia beads together with a paint shaker. Dispersion treatment for 6 hours to obtain a dispersion liquid, and the dispersion liquid is centrifuged at 23 ° C. for 17 hours.
Centrifuge at 968 × g (g is gravitational acceleration) for 3 hours to obtain a supernatant. This corresponds to the case where all the pigments in the dispersion liquid are centrifugally sedimented and the dye is not adsorbed on the pigment at all.
0.87 wt% dye aqueous solution [ie, water (45.5 g) and dye (0.4 g) concentration (0.4 / 45.9 × 100 = 0.87 wt%) dye aqueous solution) ]] Is obtained. The above supernatant liquid and the above 0.87 wt%
High performance liquid chromatography (High Performance Liquid Chromatography) measurement is carried out for each of the dye aqueous solutions, and it is determined by the following formula (II) based on the obtained HPLC peak area derived from the dye.

[0012]

[Equation 4] HPLC measurement conditions: Detection wavelength 254 nm, column temperature 40 ° C., eluent acetonitrile water (adjust the concentration of acetonitrile so that the main peak is detected within 60 minutes of measurement time) Flow rate 1.0 ml / min Injection volume 2.0 μl (no dilution) When measuring, the column is not particularly limited as long as it can detect the water-soluble dye, but the commonly used separation mode is reversed. A phase column is preferred.
The chromatographic pack is not particularly limited as long as it can process data from the HPLC detector.

The recording liquid of the present invention is as follows.
Two or more kinds of pigments and / or two or more kinds of dyes may be used in combination, and in the case of a mixed dye type recording liquid, the dye of the dispersion liquid is adjusted according to the mixing ratio of the dyes in the recording liquid. Dye mixture. Similarly, when a recording liquid of mixed pigment type is used, the red pigment of the dispersion liquid is used as a pigment mixture. In the case of the recording liquid of the mixed dye and the mixed pigment, the dye and the pigment of the dispersion liquid are a dye mixture and a pigment mixture which are adjusted to the respective mixing ratios in the recording liquid. In the case of a mixed dye-based recording liquid, the dye of the 0.87 wt% aqueous dye solution in the formula (II) is a dye mixture that matches the mixing ratio of the dye in the recording liquid.

In the recording liquid of the present invention, the dye adsorption amount (g / g) represented by the above formula (I) is usually 0.
A dye of 02 g / g or more, preferably 0.03 g / g or more, and more preferably 0.04 g / g or more is used.
If the adsorption amount is less than 0.02 g / g, it is difficult to obtain the pigment dispersion effect or it becomes difficult to obtain sufficient dispersion stability.
The larger the amount of dye adsorbed on the pigment, the more preferable, but there is a theoretical upper limit to the amount of dye adsorbed, and when the amount of dye is increased with the pigment concentration kept constant, the amount of dye adsorbed becomes constant from a certain addition amount ( Since this adsorption amount will be referred to as "saturated adsorption amount" below),
The upper limit of the dye adsorption amount is specified by the saturated adsorption amount. The saturated adsorption amount is determined by the types of pigments and dyes used and cannot be generally stated, but is generally 0.01 to 0.
It is about 1 g / g. Here, in the recording liquid of the present invention, a dye having an adsorption amount of less than 0.02 g / g with respect to the red pigment may be partially used as long as it does not adversely affect the performance, but the amount used is usually The amount is 30% by weight or less, preferably 20% by weight or less, more preferably 10% by weight or less, further preferably 5% by weight or less, particularly preferably 1% by weight or less, based on the total amount of the dye.

The coexistence of the nonionic and anionic surfactants, which is the characteristic of the above 3), allows the interface to be taken into consideration while considering the components such as pigments, dyes, various additives and water-soluble organic medium of the recording liquid. It is carried out by using a combination of a nonionic surfactant and an anionic surfactant as the activator.

(Pigment) The red pigment used in the present invention has an aromatic ring skeleton structure, particularly an aromatic condensed polycyclic skeleton structure, and has high reactivity with the functional groups of the dye molecule described later. It is desirable to select and use a pigment containing as few functional groups as possible. If the pigment has many reactive functional groups,
Adsorption due to chemical reaction with the functional group of dye molecule is likely to occur, secondary aggregation is likely to occur due to the hydrophobic part of the adsorbed dye or unreacted functional group, and the particle size of the dispersion increases and storage stability of recording liquid The property is likely to decrease. Moreover, as described above, when the dye is chemically adsorbed on the surface of the pigment due to a chemical reaction with the functional group of the pigment, the dispersion treatment with the surfactant does not allow the dye to be appropriately replaced with the surfactant, resulting in electrostatic repulsion. Dispersion stability is maintained only by itself, and since there is no steric repulsion in the recording liquid containing an organic solvent, storage stability tends to deteriorate, which is not preferable. Furthermore, when the skeletal structure of the dye molecule described below is similar to the skeletal structure of the pigment molecule, particularly when the skeletal structure of the dye molecule is an aromatic condensed polycycle,
It is desirable because many dyes can be stably adsorbed on the pigment surface.

Specific examples of the red pigment used in the present invention include CI Pigment Red-122 and -20.
2, -206, -207, -209, CI Pigme
quinacridone pigments such as ntViolet-19; C.
Xanthene-based pigments such as I. Pigment Red-81 and -173; Perylene-based pigments such as C. I. Pigment Red-123 and C. I. Pigment Red-1
Anthantrone-based pigments such as 68; CI Pigment
Red-5, -7, -12, -112, -146,-
Examples thereof include monoazo pigments such as 147. The structural formulas of typical quinacridone pigments, xanthene pigments, perylene pigments, anthanthrone pigments and monoazo pigments are shown below.

[0018]

[Chemical 1]

[0019]

[Chemical 2]

[0020]

[Chemical 3]

Among these, the quinacridone pigment is
It is particularly preferable because it has excellent durability as a printed matter, has good color development with respect to other pigments, and can be miniaturized. The red pigment used in the present invention has an average particle diameter of 500 nm or less, preferably 200 nm or less, in view of its printing performance, color characteristics and weather resistance of the printed matter. In addition, the lower limit is usually 20 nm or more, and if it is less than this, the weather resistance tends to decrease. The molecular weight of the red pigment is not particularly limited, but is usually 200 or more, preferably 300 or more, and usually 2000 or less, preferably 1500 or less from the viewpoint of dispersibility and the like.

(Dye) The dye used in the present invention is, in the pigment dispersion liquid used for the ink jet recording liquid, reversibly adsorbed to the red pigment at least without any chemical reaction as described above, and It is necessary to select a dye having a high adsorptivity to the pigment. As such a dye, a dye having a skeletal structure similar to that of the red pigment is particularly preferable because it easily physically adsorbs. The skeletal structure similarity is derived from the ring structure that creates planarity in the chemical structure of the dye molecule and the pigment molecule, the stack of π electrons in the dye molecule and the pigment molecule, and the electrical attraction of the functional group. One is mentioned as a combination that produces stronger physisorption. When a quinacridone-based pigment is used as the red pigment, a xanthene-based dye, an anthraquinone-based dye or the like is preferable in terms of a combination of similar skeleton structures of an aromatic condensed polycyclic system suitable for physical adsorption.

The number of dissociative groups such as hydroxyl groups, amino groups, carboxyl groups or sulfonic acid groups per dye molecule is preferably 1 or more and 4 or less, and more preferably free acid. The form of -C
It is particularly preferable that the compound has a dissociative group represented by at least one of OOH and —SO ₃ H, and the number thereof is 1 or more and 2 or less per dye molecule. If the dye molecule does not have a dissociative group, it becomes difficult to obtain the effect of dispersing the dye in the aqueous medium due to the adsorption of the dye on the red pigment. On the other hand, if it the number of dissociable groups represented by -COOH and -SO ₃ H is three or more, dyes liable dissolved in medium of the recording liquid than the adsorbed red pigment surface dye red pigment It becomes difficult to obtain the dispersion effect due to adsorption. Furthermore,
Since the liquid properties of the inkjet recording liquid are usually neutral to alkaline, it is preferable that the recording liquid has an anionic group capable of dissociating in an alkaline aqueous medium and ensuring an affinity for water.

In the pigment dispersion liquid used in the recording liquid of the present invention, since the dispersive action brought about by the adsorption of the dye on the pigment surface is utilized, the dye does not necessarily have to have the same color as the pigment. The ink jet recording liquid to be obtained may be appropriately selected so as to have a desired tint, but in order not to affect the tint of the pigment, a dye of the same color type as the pigment is used in at least 50 parts of the total dye amount.
It is preferable to use at least 50% by weight, preferably at least 60% by weight, more preferably at least 70% by weight, further preferably at least 80% by weight, particularly preferably at least 90% by weight, and most preferably at least 95% by weight. Here, the red dye is preferably a dye which gives a red hue represented by 5RP (magenta) to 2.5YR (yellow red) in the Munsell hue circle.

The type of dye is determined in consideration of the balance with the pigment to be used as described above, and specific examples include the following aromatic condensed polycyclic compounds.
These, as seen from the structural formula shown below, both, in the form of dye per molecule free acid, the number of dissociable groups represented by -COOH and -SO ₃ H is two or less.

Xanthene type dye: CI Acid Re
d-51, -87, -91, -92, -94, -95,
-98 etc .; Anthraquinone type dye: CI Acid Red-8
0, -83, CI Acid Violet-34,-
39, -43, etc .; Monoazo dyes: CI Acid Red-1, -4,
-8, -13, -14, -15, -26, -35, -3
7, CI Direct Red-20, -51, C.I.
I. Acid Violet-7 etc .; Disazo dyes: C. I. Acid Red-73, C.I.
I. Direct Red-1, -2, -8, -13,
-28, -31, -33, -37, -39, -59,-
81, -90, -110, etc .;

[0027]

[Chemical 4]

[0028]

[Chemical 5]

[0029]

[Chemical 6]

[0030]

[Chemical 7]

[0031]

[Chemical 8]

[0032]

[Chemical 9]

[0033]

[Chemical 10]

The molecular weight of the dye used in the present invention is not particularly limited, but it is usually 200 or more, preferably 250 or more from the viewpoint of adsorption to pigments, dispersion performance and the like.
Usually, it is 1500 or less, preferably 1000 or less.
Generally, commercially available pigments and dyes contain various contaminants, and when used as they are for inkjet recording liquids, the presence of these contaminants causes ejection when the recording liquid is printed by an inkjet printer. In many cases, it causes printing defects such as deterioration of properties and adversely affects the storage stability of the recording liquid, thus impairing the properties of the recording liquid. Therefore, it is desirable that the pigments and dyes used in the ink jet recording liquid of the present invention be removed by preliminary purification of these contaminants prior to use. Examples of these impurities contained in the pigments and dyes include those mixed with reaction reagents used in the manufacturing process, catalysts, and eluates from devices, etc., such as Ca, Mg, Zn, Fe and C.
Various metal components such as u, Al, and Si are included. As a method for removing these contaminants, an ordinary method used as a method for purifying pigments and dyes can be adopted. For example, removal of metal ions by an ion exchange resin, removal of inorganic ions by a reverse osmosis membrane method, removal of insolubles by filtration with a membrane filter, removal of organic impurities by crystallization and the like can be mentioned. Usually, these purification methods are used in combination. The respective contents of impurities, for example, metal ions in the purified pigment and dye are
Usually, it is lowered to about 100 ppm.

The total amount of pigments and dyes in the ink jet recording liquid in the present invention is
The weight ratio to the total weight is usually 0.1% or more, preferably 0.3% or more, more preferably 0.5% or more. If the total amount of the pigment and the dye is too large, problems may occur from the viewpoint of dispersion stability.
It is 5% or less, preferably 10% or less. As for the ratio of the pigment to the total dye, if the amount of the dye relative to the pigment is too small, the pigment agglomerates and the dispersion stability is significantly reduced.
The amount of the dye based on 00 parts by weight is 2 parts by weight or more, preferably 3 parts by weight or more, more preferably 4 parts by weight or more, further preferably 5 parts by weight or more, and particularly preferably 6 parts by weight or more. However, when the amount of the dye is too much, the fastness of the printed matter derived from the dye is remarkably deteriorated, and the dispersion stability of the pigment dispersion tends to be decreased, which is not preferable.
The amount of the dye based on 00 parts by weight is 100 parts by weight or less, preferably 50 parts by weight or less, more preferably 33 parts by weight or less.

On the other hand, as described above, the amount of the dye adsorbed to the pigment is limited, and the amount of the dye adsorbed to the pigment becomes constant even if the dye concentration is increased for a certain concentration of the pigment. . Therefore, since the amount of dye used for the pigment depends on this saturated adsorption amount as well, when the minimum charge dye amount that gives the saturated adsorption amount for the pigment of a specific concentration is defined as the "saturated adsorption dye amount". The amount of dye to be added is set to 1/10 times or more, preferably 1/3 times or more, and 20 times or less, preferably 10 times or less, more preferably 5 times or less of the saturated adsorption dye amount. Preferably.
When the amount of the dye is less than this, the dispersion stability of the pigment is significantly reduced, and when the amount of the dye is more than this, the dye that is not adsorbed to the pigment (hereinafter this dye is referred to as "free dye").
Is likely to cause pigment flocculation, which is not preferable.

(Surfactant) In the present invention, a combination of a red pigment and a dye having a specific adsorptivity for the red pigment is selected and used, and a combination of a nonionic surfactant and an anionic surfactant is used. By using both in combination, an inkjet recording liquid having good dispersibility and good printability and storage stability can be obtained. In the present invention, by using a nonionic surfactant and an anionic surfactant in combination, an inkjet recording liquid having excellent dispersibility and storage stability can be obtained.
The details of why such an excellent effect is obtained are not always clear. However, the liquid properties of the inkjet recording liquid are usually neutral to alkaline, and in addition,
By using an aqueous medium in which water is mixed with a water-soluble organic solvent,
It is adjusted to increase the wettability and penetrability of the color material into the paper, enhance the moisture retention of the nozzle surface of the printer head, and maintain the startup performance of the printer.
Using an anionic surfactant and a nonionic surfactant in combination with a dye ensures that they dissociate in an aqueous medium to ensure affinity and dispersibility for water, and
To secure the affinity and dispersibility for organic solvents,
It is considered that they contribute synergistically.

The anionic surfactant used in the present invention is not particularly limited, and examples thereof include fatty acid salts, alkyl sulfate ester salts, alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkyl sulfosuccinates, alkyl diphenyl ether sulfone. Acid salts, alkyl phosphates, polyoxyethylene alkyl sulfates, polyoxyethylene alkyl allyl sulfates, alkane sulfonates, naphthalene sulfonic acid formalin condensates, polyoxyethylene alkyl phosphates, α-olefins Sulfonates can be used, and specific examples thereof include polyoxyethylene stearyl sulfonate, dodecyl sulfonate, dodecyl benzene sulfonate, and the like. Among these anionic surfactants,
Alkyl sulfates, polyoxyethylene alkyl sulfates, polyoxyethylene alkylallyl sulfates, alkylbenzene sulfonates and the like are preferable.

The nonionic surfactant is not particularly limited, but polyoxyethylene alkyl ethers,
Polyoxyethylene alkyl allyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene derivatives, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, glycerin fatty acid esters, polyoxy Examples thereof include ethylene fatty acid esters and polyoxyethylene alkylamines. Among these nonionic surfactants, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl allyl ethers and the like are preferable.

The molecular weight of the above nonionic and anionic surfactants is usually about 2000 or less, preferably about 1500 or less. If the molecular weight is too high, the viscosity of the liquid when used as an inkjet recording liquid increases, and the ejection property tends to deteriorate in inkjet recording. The ratio (weight ratio) of the nonionic surfactant and the anionic surfactant is:
Usually, the amount of the anionic surfactant is 1% by weight or more, preferably 2% by weight or more, more preferably, based on 100 parts by weight of the nonionic surfactant, although it depends on the liquidity of the recording liquid for inkjet. 3% by weight or more, more preferably 5
It is used in an amount of not less than 10% by weight, particularly preferably not less than 10% by weight. However, if the amount of anionic surfactant is too large, it may become unstable in terms of dispersion stability.
Usually, it is 5 times by weight or less, preferably 2.5 times by weight or less. Further, the total amount of the surfactant is 0.01% by weight or more, preferably 0.1% by weight or more, more preferably 0.2% by weight or more, based on the total weight of the recording liquid, while the upper limit is The content is 5% by weight or less, preferably 3% by weight or less, more preferably 2% by weight or less.

In the ink jet recording liquid of the present invention, the red pigment, the dye and the surfactant to be used retain the state that the dye is adsorbed to the red pigment and the anionic and nonionic surfactants coexist as described above. As long as the effects of the present invention such as dispersion stability and storage stability can be obtained thereby, other pigments, dyes and surfactants other than those mentioned above may be contained if necessary. Even in such a case, it is preferable that the red pigment, the dye and the surfactant which exhibit the above state in the recording liquid of the present invention are present as the main components of the respective components in the recording liquid. It is preferable that 70% or more, and particularly preferably 80% or more of each component be present.

(Method for Producing Inkjet Recording Liquid) Next, a method for preparing the inkjet recording liquid of the present invention will be described. The ink jet recording liquid of the present invention is prepared by mixing a red pigment, a dye and / or dye aqueous medium solution, and an aqueous medium to perform a primary dispersion treatment of the red pigment and the dye. It is obtained by carrying out a secondary dispersion treatment by adding a surfactant and an anionic surfactant, and / or an aqueous medium solution of these surfactants, and is simple and industrially advantageous to produce. You can That is, according to the method of the present invention, first, the red pigment and the dye are dispersed in an aqueous medium (primary dispersion treatment), and then further dispersed with a surfactant (secondary dispersion treatment). To obtain a dispersion effect of the pigment by the dye by stably adsorbing the dye on the surface, and further, by partially replacing a part of the dye with a surfactant suitable for the liquid properties of the recording liquid, the recording liquid of the dispersion can be obtained. It is possible to produce a recording liquid having excellent dispersibility and storage stability by suppressing secondary aggregation in the above.

In the method of the present invention, first, a red pigment, a dye and / or a dye aqueous medium solution, and an aqueous medium are mixed and subjected to a primary dispersion treatment, whereby the dye is adsorbed and dispersed in the red pigment. Get the liquid. The total amount of the pigment and dye in the red pigment / dye dispersion is usually 1 to 30% by weight relative to the total dispersion, and preferably 3 to 2
It is 0%. If it is less than 1%, the concentration tends to be insufficient for using the dispersion as a recording liquid, and if it exceeds 30%, the dispersion stability tends to decrease, which is not preferable.

A disperser used for dispersion processing is usually
Various dispersers used for pigment dispersion can be used as appropriate. The disperser is not particularly limited, but a paint shaker, a ball mill, a sand mill, an attritor, a pearl mill, a co-ball mill, a homomixer, a homogenizer, a wet jet mill, an ultrasonic homogenizer, or the like can be used. Glass beads, zirconia beads, alumina beads, magnetic beads, and styrene beads can be used as the dispersing machine that uses media. Among them, a preferable dispersion treatment recipe is a method in which beads are used as a medium for dispersion by a mill and then an ultrasonic homogenizer is used for dispersion. The method for obtaining the pigment / dye dispersion having a preferable particle size is not particularly limited, but the size of the dispersion medium of the disperser is reduced.
Various methods such as increasing the filling rate of the dispersion medium, increasing the pigment concentration in the dispersion, prolonging the treatment time, and classifying with a filter or a centrifuge after the dispersion, or a method thereof is appropriately used. Used in combination. Although not particularly specified, if an undesired phenomenon such as thickening or foaming of the dispersion liquid occurs due to heat generation during dispersion, it is desirable to perform the dispersion treatment while cooling.

The thus-prepared pigment / dye dispersion is used as it is, or the pigment / dye dispersion diluted with deionized water or pure water is added to the above-mentioned anionic and nonionic surfactants or their aqueous surfactants. The medium solution is added and the mixture is subjected to a secondary dispersion treatment to form a dispersion. As is conventionally done, when a surfactant or a polymer dispersant is adsorbed on a pigment and then a dye is adsorbed, or a surfactant or a polymer dispersant and a dye are simultaneously subjected to a dispersion treatment on the pigment. In this case, the amount of the dye adsorbed is lower than that of the dispersion liquid prepared by the method of the present invention, and the particle size is larger than that of the dispersion liquid or the dispersion stability is lower, which is not preferable. The reason is not clear, but if the pigment and the surfactant are mixed first, the surfactant will be adsorbed to the pigment first, and the adsorption of the dye added later on to the pigment will be inhibited, resulting in a sufficient dispersion effect. Is presumed not to occur.

A water-soluble organic solvent may be added to the pigment / dye dispersion prior to dispersing the surfactant in the pigment / dye dispersion. The water-soluble organic solvent includes, but is not limited to, ethylene glycol, diethylene glycol, ethanol and the like. The disperser used for such dispersion treatment is not limited to this, but includes a ball mill, a sand mill, an attritor,
A pearl mill, a co-ball mill, a homomixer, a homogenizer, a magnetic stirrer, an ultrasonic homogenizer, etc. can be used. Glass beads, zirconia beads, alumina beads, magnetic beads, and styrene beads can be used as the dispersing machine that uses media.

The ink jet recording liquid of the present invention comprises the dispersion liquid obtained as described above, an aqueous medium, and various other additives which are added as necessary. The ink jet recording liquid, that is, the ink, is prepared by dissolving the pigment dispersion liquid containing the pigment, dye, surfactant and aqueous medium prepared as described above, or by diluting it with water and then using a water-soluble organic solvent, It can be manufactured by mixing the additives of. The ink can be mixed with, but not limited to, a magnetic stirrer, an ordinary agitator equipped with blades, a high speed disperser, an ultrasonic disperser, a homogenizer, and the like.

A suitable aqueous medium used in the ink jet recording liquid of the present invention is a mixed solvent of water and a water-soluble organic solvent. As the water used here, it is desirable to use deionized water or pure water instead of general water containing various ions, as in the medium of the dispersion liquid.

The water-soluble organic solvent used in the present invention is not limited to this, and examples thereof include ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, triethylene glycol, tetraethylene glycol and trimethylolpropane. Polyhydric alcohols such as 1,5-pentanediol, 1,2,6-hexanetriol, glycerin; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, Diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, propylene glycol monobutyl ether, dipropylene Polyhydric alcohol derivatives such as recall monobutyl ether; pyrrolidone, N- methyl-2
-Nitrogen-containing solvents such as pyrrolidone, cyclohexylpyrrolidone, monoethanolamine, diethanolamine, triethanolamine; alcohols such as ethanol, isopropyl alcohol, butyl alcohol, benzyl alcohol; or thiodiethanol, thiodiglycerol, sulfolane, dimethyl sulfoxide, etc. Sulfur-containing solvent: propylene carbonate, ethylene carbonate and the like can be used. The content of water in the recording liquid is usually 30% by weight.
The above is preferably used in the range of 50% by weight or more, and is usually used in the range of 95% by weight or less, preferably 90% by weight or less. Further, the content of the water-soluble organic solvent,
Although not particularly limited, it is usually used in the range of 0.1% by weight or more, preferably 1% by weight or more, more preferably 5% by weight or more, usually 60% by weight or less, more preferably 4% by weight or less.
It is used in an amount of 0% by weight or less, particularly preferably 30% by weight or less. In particular, as the use ratio of the water and the water-soluble organic solvent, it is preferable that the amount of water used is equal to or more than the amount of the water-soluble organic solvent, and is in the range of 19 times or less the amount of the water-soluble organic solvent. Is preferred.

The additives can be appropriately selected and used from the various additives usually used in the preparation of ink jet recording liquids, if necessary, within a range that does not impair the stability of the dispersion liquid. Tension adjusting agent, pH adjusting agent,
Examples of the antiseptic agent, chelating agent, water-dispersible resin, conductivity adjusting agent, defoaming agent, etc., are not particularly limited thereto. Specific examples of the additives will be given below.

The surface tension adjusting agent is mainly for the purpose of adjusting the effect of penetrating the recording liquid into paper, and is anionic, cationic,
A nonionic or polymeric surfactant is used.
The anionic surfactant is not particularly limited,
Fatty acid salts, alkyl sulfate ester salts, alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkyl sulfosuccinates, alkyl diphenyl ether sulfonates, alkyl phosphates,
Polyoxyethylene alkyl sulfate ester salts, polyoxyethylene alkyl allyl sulfate ester salts, alkane sulfonates, naphthalene sulfonic acid formalin condensates, polyoxyethylene alkyl phosphate esters, α-olefin sulfonates and the like can be used.

The nonionic surfactant is not particularly limited, but polyoxyethylene alkyl ethers,
Polyoxyethylene alkyl allyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene derivatives, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, glycerin fatty acid esters, polyoxy Examples thereof include ethylene fatty acid esters and polyoxyethylene alkylamines. The cationic surfactant is not particularly limited, and examples thereof include a tetraalkylammonium salt, an alkylamine salt, a benzalkonium salt, an alkylpyridinium salt, and an imidazolium salt. In addition, silicone-based surfactants such as polysiloxane oxyethylene adducts,
Fluorosurfactants such as perfluoroalkylcarboxylates, perfluoroalkylsulfonates and oxyethylene perfluoroalkyl ethers, and surfactants such as biosurfactants such as rhamnolipid and lysolecithin can also be used.

In the present invention, among the above-mentioned surfactants, it is preferable to use the same surfactant as that used for preparing the dispersion liquid from the viewpoint of dispersion stability. That is,
It is desirable to use a surfactant selected from the group consisting of anionic surfactants and nonionic surfactants,
Above all, it is more preferable to use a surfactant having a similar structure or the same surfactant. The added amount is 0 to 5% by weight, preferably 0 to 3% by total amount contained in the recording liquid.
%, More preferably 0 to 2% by weight.

The antifungal agent is added to the recording liquid in order to prevent the development of fungi and bacteria, but the antifungal agent is not particularly limited, and sodium dehydroacetate, sodium benzoate, etc. are used. . These are 0.0 in the recording liquid.
It is preferably contained in the range of 5 to 1.0% by weight. The chelating agent is used for blocking the metal in the recording liquid and preventing metal deposition in the nozzle. The chelating agent is not particularly limited, but a sodium salt of ethylenediaminetetraacetic acid, a diammonium salt of ethylenediaminetetraacetic acid, or the like is used. These are used in the recording liquid in the range of 0.005 to 0.5% by weight.

The pH of the recording liquid is adjusted to obtain stability of the recording liquid or stability with the recording liquid pipe in the recording apparatus, but it is not particularly limited, but sodium hydroxide, nitric acid, ammonia or the like is used. A pH adjusting agent, a buffering agent such as a phosphate, etc. can be used. The pH of the recording liquid is usually p
It is adjusted to about H6-11. Further, an antifoaming agent may be added to prevent the generation of bubbles in the recording liquid.

In order to improve the fixability on paper and the water resistance of the ink coating film, the ink jet recording liquid of the present invention contains
A water-dispersible resin can be used as long as the effect of the present invention is not impaired. The water-dispersible resin is not particularly limited, but polyester resin, polyamide resin, polyurethane resin, epoxy resin, butadiene resin, petroleum resin, fluorine resin, polyamino acid, dextrin, pectin, arginine, glycogen, Chitin, polynucleic acid, carboxymethyl cellulose, carboxymethyl dextran, and water-soluble vinyl resins such as acrylic resin, styrene-acrylic resin, polyvinyl alcohol resin, vinyl acetate resin, polyvinylpyrrolidone resin, polyvinylamine Examples thereof include resin based resins, polyallylamine based resins, polyvinyl apyridine based resins, and polydiallyldimethylammonium chloride based resins. The water-dispersible resin is usually added to the recording liquid in an amount of 0.1
It is used in the range of 10 to 10% by weight, preferably 0.5 to 5% by weight.

[0057]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. The methods of measuring the particle size of the pigment dispersions, storage stability, and evaluation of the dye adsorption amount on the pigment in Examples and Comparative Examples were carried out by the following methods. Further, the dyes used in the following examples and comparative examples,
Prior to each use, insoluble components such as inorganic salts and metal salts are removed by membrane filtration, etc., and organic impurities are removed by crystallization, and the content of each metal ion of Ca, Mg, Zn, Fe, Cu, Al is contained. Was 100ppm or less for each, and used with reduced impurities.

(1) Particle size The ink jet recording liquid was diluted 10,000 times with deionized water and measured with a DLS7000 Otsuka Electronics Co., Ltd. using a He-Ne laser, and the average particle size value was calculated as Cumula.
It was calculated by the nt method.

(2) Storage stability The ink jet recording liquid was allowed to stand in a thermostatic chamber at 23 ° C. and a relative humidity of 50% for one week, and the particle diameter of the ink jet recording liquid extracted from the lower part of the container was measured. The storage stability was evaluated by making a comparison with the particle diameter of the recording liquid for ink jet of.

(3) Dye adsorption amount The dye adsorption amount was measured by the following method. That is, at 23 ° C., 4.1 g of the solid content of the red pigment (pigment amount in the dispersion liquid) and 0.4 g of the dye in the solid content amount (total dye amount of the dispersion liquid) were weighed, and water was added thereto. The total amount is 50 g, together with 75 g of 0.5 mmφ zirconia beads,
A dispersion liquid was obtained by performing dispersion treatment for 6 hours with a paint shaker (manufactured by Asada Iron Works Co., Ltd .; Paint shaker PC, vibration frequency 535 rpm (50 Hz)). The obtained dispersion was centrifuged at room temperature with an Inverter Micro Centrifuge 1120 (produced by Kubota Corporation) at 14000 rpm (centrifugal force: 17968 × g) for 3 hours to obtain a supernatant. A HPLC solution (detector: L-7420 type, manufactured by Hitachi, Ltd.) of a dye aqueous solution (abbreviated as dye aqueous solution) having the same concentration as the total dyes in the supernatant liquid and the dispersion liquid, that is, 0.87 wt% is used. Pump: L-7110 type)
H is derived from the dye obtained by measuring under the following conditions.
Based on the PLC peak area, the dye adsorption rate and the dye adsorption amount were determined by the following formulas.

[HPLC measurement conditions] Detection wavelength 254 nm column Inertsil-ODS 5 μ (4.6 mmφ × 250 mmL)
(GL Sciences Inc.) Column temperature 40 ° C Eluent Acetonitrile water (Adjust the concentration of acetonitrile so that the main peak is detected within 60 minutes of measuring time) Flow rate 1.0 ml / min Injection volume 2.0 μl (without dilution) Chromatopack CR-6A (Shimadzu Corporation)

[0062]

[Equation 5]

[Equation 6]

(4) Printing test After the black cartridge is filled with ink, DeskJ
Plain paper (Xerox Co., Ltd. XX402) with an et990Cxi printer (made by Hewlett-Packard Co., Ltd.) and a BJ-F870 printer (made by Canon Co., Ltd.)
Printing was performed on 4) to evaluate whether printing was possible. Evaluation ◯: Almost no blurring, X: Severe blurring and unreadable characters In addition, in Examples 1 to 4, it was also evaluated whether or not it was possible to print again after one week with the ink kept in the cartridge. Evaluation ○: Printing is possible after one week ×: Printing is not possible after one week

Example 1 Quinacridone red pigment PR-122 (Dainichi Seika Kogyo Co., Ltd .; ECR-187; paste; solid content 29.7)
%) 13.8 g, xanthene dye AR-51 (CIAc
idRed51: Aldrich (company)) 4% of 10% aqueous solution and 32.2 g of deionized water were mixed, and paint shaker with 0.5 mmΦ zirconia beads as media (Asada Iron Works Co., Ltd .: Paint shaker PC frequency 535 rpm (50 Hz)).
Was dispersed for 6 hours to obtain a dispersion liquid. The amount of dye adsorbed in the obtained dispersion was 0.07 g / g. PR-1 above
40.9 g of 22 and a 10% aqueous solution of AR-51 1
3.5 g and 95.6 g of deionized water were weighed in a 200 ml beaker, the beaker was immersed in ice water, and dispersed with an ultrasonic homogenizer (Nippon Seiki Seisakusho Co., Ltd .; US-300T; used tip 26 mmφ) for 3 minutes to prepare a liquid. After the temperature reached 20 ℃, repeat the dispersion for 3 minutes, and the total dispersion time is 6
Dispersion was performed until 0 minutes to obtain a dispersion liquid (a). Immediately after preparing the dispersion liquid (a), the nonionic surfactant Brij76 (polyoxyethylene (10) stearyl ether (molecular weight = 711.04); Aldrich (company)) was added to the dispersion liquid (a) (7.4 g). 0.1 g, anionic surfactant SDS
(Sodium dodecyl sulfate (molecular weight = 288.38);
0.1 g of Wako Pure Chemical Industries, Ltd. was added, the mixture was stirred for 15 minutes with a magnetic stirrer (1000 rpm), and further subjected to ultrasonic dispersion treatment for 15 minutes to obtain a dispersion liquid (b).

The obtained dispersion liquid (b) was prepared according to the following formulation.
Inked. (Preparation of Ink) Dispersion (b) 7.6 g Deionized water 4.6 g Triethylene glycol monobutyl ether 2.0 g Diethylene glycol 1.8 g Glycerin 2.0 g Triethanolamine 0.2 g Urea 1.8 g The above components are mixed. After stirring for 15 minutes with a magnetic stirrer (1000 rpm) and ultrasonic dispersion treatment for 15 minutes, the pH was adjusted to 9.6 with an aqueous NaOH solution to obtain an ink. The evaluation results of the ink are shown in Tables 1 and 2.

Example 2 Using the dispersion (a) of Example 1, the nonionic surfactant of the dispersion (b) was added to Brij78 (polyoxyethylene (20)).
Dispersion liquid in the same manner as in Example 1 except that stearyl ether (Mw = 1151.57; Aldrich (company)) was used.
(c) was obtained. An ink was obtained from the obtained dispersion liquid (c) using the same additives and adjustment methods as in Example 1. The evaluation results of the ink are shown in Tables 1 and 2.

Example 3 4.1 g of quinacridone red pigment PR-122 (Dainichi Seika Kogyo KK; ECR-184), anthraquinone dye AV-43 (CIAcidViolet43: Tokyo Chemical Industry Co., Ltd.) 1
4 g of 0% aqueous solution and 41.9 g of deionized water were mixed, and
Paint shaker with 5mmΦ zirconia beads as media (Asada Iron Works Co., Ltd .: Paint shaker PC, frequency 5
Dispersion (d) by dispersing for 6 hours using 35 rpm (50 Hz)
Got The amount of dye adsorbed in the obtained dispersion liquid (d) is 0.06 g.
/ G. In the combination of PR-122 and AV-43 described above, the dispersion was prepared in the same manner as the preparation of the dispersion (a) of Example 1, and the dispersion was immediately used, and the dispersion (b) of Example 1 was used. A dispersion liquid was obtained by the same surfactant and adjustment method as in 1., and then an ink was obtained by using the same additive and adjustment method as in Example 1. The evaluation results of the ink are shown in Tables 1 and 2.

Example 4 PR-122 (Dainichi Seika Kogyo KK; ECR-18)
4) 4.1 g, xanthene dye AR-87 (CI.AcidR
ed87: Tokyo Kasei Co., Ltd.) 4% 10% aqueous solution, 4 deionized water
1.9 g was mixed, and a paint shaker (Asada Iron Works Co., Ltd.) using 0.5 mmΦ zirconia beads as a medium.
6 using a paint shaker PC frequency 535 rpm (50 Hz))
Time dispersed. The amount of dye adsorbed in the obtained dispersion liquid (e) is 0.
It was 04 g / g. The PR-122 and the AR-
In the combination of 87, after preparing the dispersion liquid in the same manner as in the preparation of the dispersion liquid (a) of Example 1, immediately after using the dispersion liquid,
A dispersion liquid was obtained by the same preparation method as the dispersion liquid (b) of Example 1, and then an ink was obtained by using the same dispersion liquid and preparation method as in Example 1.

Comparative Example 1 Dispersion (f) was prepared in the same manner except that the dispersion (a) of Example 1 was used and the total amount of the surfactant of dispersion (b) was the nonionic surfactant Brij76. Obtained. An ink was obtained from the obtained dispersion liquid (f) using the same additives and adjusting method as in Example 1. The evaluation results of the ink are shown in Tables 1 and 2.

Comparative Example 2 A dispersion (g) was prepared in the same manner except that the dispersion (a) of Example 1 was used and the total amount of the surfactant of the dispersion (b) was the anionic surfactant SDS. Obtained. An ink was obtained from the obtained dispersion liquid (g) using the same additives and adjusting method as in Example 1. The evaluation results of the ink are shown in Tables 1 and 2.

Comparative Example 3 PR-122 (Dainichi Seika Kogyo KK; ECR-18
4) 4.1 g, monoazo dye AR-8 (CIAcidRed
8: Sumitomo Chemical Co., Ltd.) 4g of 10% aqueous solution and 41.9g of deionized water were mixed, and 0.5mmΦ zirconia beads were used as media for paint shaker (Asada Iron Works Co., Ltd .: Paint shaker PC, frequency 535rpm (50Hz) )) For 6 hours to obtain a dispersion (h). The resulting dispersion
The dye adsorption amount of (h) was 0.01 g / g. Immediately after the adjustment, the dispersion liquid (h) was used to obtain the dispersion liquid (i) by the same preparation method as the dispersion liquid (b) of Example 1 with the same surfactant. An ink was obtained from the dispersion liquid (i) using the same additives and adjusting method as in Example 1. The evaluation results of the ink are shown in Tables 1 and 2. This result indicates that the difference in the molecular skeleton structure between the pigment and the dye is small in the amount of dye adsorbed and inferior in physical adsorption.

Comparative Example 4 PR-122 (Dainichi Seika Kogyo KK; ECR-18
4) 4.1 g, 4 g of 10% aqueous solution of red dye (formula 1 below) described in Example 1 of JP-A-8-218019,
Deionized water (41.9 g) was mixed, and 0.5 mmΦ zirconia beads were used as media for paint shaker (Asada Tekko KK: Paint shaker PC, frequency 535 rpm (50H
z)) for 6 hours to obtain a dispersion liquid (j). The amount of dye adsorbed in the obtained dispersion liquid (j) was 0.01 g / g.
Immediately after the adjustment, the dispersion liquid (j) was used to obtain the dispersion liquid (k) by the same preparation method as the dispersion liquid (b) of Example 1 and the same adjusting method. Dispersion
An ink was obtained by using (k) with the same additives and adjusting method as in Example 1. The evaluation results of the ink are shown in Tables 1 and 2.

[0073]

[Chemical 11]

[0074]

[Table 1]

[0075]

[Table 2]

[0076]

According to the present invention, a combination of a red pigment and a dye having a specific adsorptivity for the red pigment is selected, and a combination of a nonionic surfactant and an anionic surfactant is used. This makes it possible to control the dispersion treatment during preparation of the recording liquid, and to obtain an inkjet recording liquid having good dispersibility and good printability and storage stability.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hideaki Tanaka             1000 Kamoshida-cho, Aoba-ku, Yokohama-shi, Kanagawa             Within Mitsubishi Chemical Corporation (72) Inventor Kazuhiro Maruyama             3-10-1, Shiohama, Kawasaki-ku, Kawasaki-shi, Kanagawa               Kawasaki Chemical Industry Co., Ltd. (72) Inventor Katsuto Kanazawa             3-10-1, Shiohama, Kawasaki-ku, Kawasaki-shi, Kanagawa               Kawasaki Chemical Industry Co., Ltd. F-term (reference) 2C056 EA26 FC02                 2H086 BA52 BA53 BA55 BA59 BA60                       BA62                 4J039 BC16 BC17 BC31 BC39 BC40                       BC50 BC55 BC68 BC69 BC72                       BC73 BC75 BC77 BC79 BE01                       BE02 BE12 BE22 BE28 CA06                       EA15 EA42 EA44 GA24

Claims (18)

[Claims] 1. An ink jet recording liquid containing a red pigment, a dye and a surfactant in an aqueous medium,
1) Red pigments and dyes include, at least in part thereof, those in which the dyes are reversibly adsorbed to the red pigments without any chemical reaction, and 2) without any chemical reaction to the red pigments. The dyes reversibly adsorbed include those having a dye adsorption amount represented by the following formula (I) of 0.02 g / g or more, and (Here, the dye adsorption rate is the supernatant liquid after removing solids from a dispersion liquid prepared using the above red pigment (4.1 g) and the above dye (0.4 g) in the absence of a surfactant. ,
And a value obtained from the ratio of the peak areas obtained by measuring the dye concentration of the dye (0.4 g) in an aqueous solution by high performance liquid chromatography. ),as well as,
3) An inkjet recording liquid, wherein a nonionic surfactant and an anionic surfactant coexist as the surfactant. 2. A red pigment in which a dye is reversibly adsorbed without a chemical reaction is obtained by contact-mixing a red pigment and a dye in the absence of a surfactant. The inkjet recording liquid according to claim 1, which is characterized in that. 3. The inkjet according to claim 1, wherein the dye reversibly adsorbed to the red pigment without involving a chemical reaction contains a dye having 1 to 4 dissociative groups. Recording liquid. 4. A dye that is reversibly adsorbed on a red pigment without involving a chemical reaction, and has a free acid form of COOH and SO _3.
The inkjet recording liquid according to claim 1, further comprising a dye having 1 or 2 dissociative groups represented by at least H. 5. The inkjet recording liquid according to claim 1, wherein the red pigment on which the dye is reversibly adsorbed without a chemical reaction contains a quinacridone pigment. 6. The ink jet recording liquid according to claim 1, wherein the dye reversibly adsorbed to the red pigment without involving a chemical reaction contains a red dye. . 7. The red pigment with which the dye is reversibly adsorbed without involving a chemical reaction, having a mean particle size of 500 nm or less is used, according to any one of claims 1 to 6. Recording liquid for inkjet. 8. A nonionic surfactant: anionic surfactant ratio in the range of 1: 0.01 to 1: 5, according to any one of claims 1 to 7. Recording liquid for inkjet. 9. The inkjet recording liquid according to claim 1, wherein the anionic surfactant and the nonionic surfactant have a weight average molecular weight of 2000 or less. 10. The weight ratio of the total amount of pigment to the total amount of dye in the ink jet recording liquid is 1: 0.02.
The recording liquid for inkjet according to any one of claims 1 to 9, wherein the recording liquid is in the range of 1 to 1: 1. 11. The inkjet recording liquid according to claim 1, further comprising a water-dispersible resin. 12. The ink jet recording liquid has a pH of 6 to 1.
The recording liquid for inkjet according to any one of claims 1 to 11, wherein the recording liquid is adjusted to 1. 13. The aqueous medium is a mixed solvent of water and a water-soluble organic solvent, and the weight ratio of water: water-soluble organic solvent in the recording liquid is 95: 5 to 50:50. Item 13. The inkjet recording liquid according to any one of items 1 to 12. 14. A red pigment, a dye and / or an aqueous medium solution of a dye, and an aqueous medium are mixed to carry out a primary dispersion treatment of the red pigment and the dye. Red pigment in which a dye is reversibly adsorbed without a chemical reaction, which is characterized in that a secondary dispersion treatment is carried out by adding an organic surface active agent and / or an aqueous medium solution of these surface active agents. And a nonionic surfactant and an anionic surfactant coexisting as the surfactant. 15. The method for producing an inkjet recording liquid according to claim 14, wherein an additional aqueous medium and / or an additive is added to the dispersion liquid after the secondary dispersion treatment. 16. The additional aqueous medium contains a water-soluble organic solvent, and the weight ratio of water: water-soluble organic solvent in the recording liquid is 9
16. The ratio of 5: 5 to 50:50.
The method for producing a recording liquid for ink jet according to 1. 17. The surface tension adjusting agent selected from the group consisting of nonionic surfactants and / or anionic surfactants is added as an additional additive, according to claim 15 or 16. 1. A method for producing an inkjet recording liquid. 18. The nonionic surfactant and / or anionic surfactant added as a surface tension adjusting agent, which is an additional additive, is at least one selected from the surfactants used in the secondary dispersion treatment. 18. The method for producing an inkjet recording liquid according to claim 15 or 17, wherein the surfactant is a surfactant.