JPH09316380A - Ink composition having excellent water resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an ink composition which is rapid in drying and can give images excellent in water resistance, etc., by mixing an alkali-soluble resin containing phenolic functional groups with a basic dye at a specified temperature and dissolving the obtained mixture in water containing a specified amount of an alkali. SOLUTION: A phenol-functional-group-containing alkali-soluble resin (e.g. phenol resin) is mixed with a basic bye (e.g. C.I. Basic Yellow 2) at a temperature ranging from the softening point of the resin to the decomposition temperature of the dye. Next, the obtained mixture is dissolved in water containing an alkali in amount enough to thoroughly dissolve the alkali-soluble resin and the basic dye to obtain an ink composition. The obtained composition can be desirably used in an ink jet recording system and has excellent stability of delivery. When this composition further contains a water-soluble monoalkyl ether of an alkylene glycol or of a polyalkylene glycol, it can give prints having still more improved dryability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION

<Field of the invention> The present invention relates to an ink composition preferably used in an inkjet recording system, and more specifically,
The present invention relates to an ink composition that forms a recorded image having excellent discharge stability and water resistance when used in an inkjet recording system.

BACKGROUND ART At present, several different ink jet recording methods are known in which a small droplet of ink is ejected from a nozzle and adhered to a recording medium such as paper. Inkjet recording method is electrostatic suction method, pneumatic feeding method,
Recording is performed by generating and ejecting small droplets by a method using electric deformation of a piezoelectric element, a method using pressure during heating and bubbling, and further adhering the ink droplets to a recording sheet.

Inks used in ink jet recording systems are well known in the art, and these inks are prepared by dispersing a water-soluble dye solution or a pigment which is relatively insoluble in water in water or an aqueous solution containing a water-soluble organic solvent. It is generally in the form of a liquid that has been allowed to flow. As the performance desired for the ink used in the inkjet recording system, generally,
1) high recording quality independent of the type of recording medium, 2) water resistance of the recorded ink independent of the type of recording medium,
3) Resistance of the recorded ink when the recording surface is lightly rubbed, 4) Quick-drying of the recorded image, which does not stain the recorded image even when continuously recording pages are overlapped, 5) Ink resistance against temperature Stability, 6) Stability of the ink that does not clog the nozzles of the recording head under the actual recording conditions, 7) Ink that lost solvent due to evaporation is redissolved in the new ink when touched Or that it is redispersed. The performance listed as 7) is
When the inkjet printer is left unused for a long time, the recording head is "cleaned" by pulsing the head with the ink stored in the ink reservoir and minimizing the evaporation of the solvent component. is important. It is needless to say that the relative importance of the above performances depends on each recording application.

[0004] Generally, some of the above performances are incompatible with other performances. For example, an ink composed of a liquid in which a pigment that is relatively difficult to dissolve is dispersed in water or an aqueous solution containing a water-soluble organic solvent, regardless of the type of recording medium,
It can be formulated so as to give extremely high recording quality and excellent water resistance of the recorded ink. The water resistance of such inks is due to the inherent water resistance of the color pigment. However, the pigment is not dissolved but dispersed in water or an aqueous solution containing a water-soluble organic solvent. Therefore, this kind of ink may lack stability at extreme temperatures or in actual recording conditions. Furthermore, it is extremely difficult to formulate this kind of ink so that the pigment is redispersed when the fresh ink and the dry ink are brought into contact with each other (for example, at the head) as described above.

In contrast, an ink in which a water-soluble dye is dissolved in water or an aqueous solution containing a water-soluble organic solvent forms a fast-drying recording image and has excellent stability against extreme temperatures and actual recording conditions. Have sex. Because the dye is water soluble,
The dye can readily redissolve upon contact between fresh and dried ink. It is relatively easy to formulate this kind of ink. However, since the dye is water-soluble, it is difficult to obtain a recorded image that is water resistant on all types of recording media.

In order to solve the above problems in an ink comprising a liquid in which a pigment which is relatively insoluble is dispersed in water or an aqueous solution containing a water-soluble organic solvent, an ink containing an alkali-soluble polymer resin is used. Compositions have been proposed.
Japanese Patent Application Laid-Open No. 53-114985 discloses an ink composition using a polymer resin containing a phenol functional group and containing an emulsion of a water-insoluble pigment or disperse dye. It is said that such an ink composition provides better color development than an ink containing no polymer. The particle size of the polymer-stabilized water-insoluble pigments or dispersed dyes is stated to be less than 3 μm.

Japanese Patent Laid-Open No. 62-11782 and Japanese Patent Publication (Kokai) No. 5-62632 disclose an ink composition containing a polyester resin containing a sulfonic acid functional group and an emulsion of a water-insoluble dye or a disperse dye. The thing is disclosed. It is said that such an ink composition can provide better water resistance than an ink containing no polymer. There is no mention in this publication of the particle size of the polymer-stabilized water-insoluble dyes or dispersed dyes.

JP-A-2-248475 discloses an ink composition containing a polymer resin containing a carboxylic acid functional group and containing an emulsion of a polymer dispersion containing either a water-soluble dye or a water-soluble pigment. Is disclosed. It is said that such an ink composition provides superior water resistance and light resistance to an ink containing no polymer. According to this publication, the alkali-soluble resin containing the ink composition was stable at 50 ° C. for 3 months.

The alkali-soluble polymers used in these three examples are believed to make a major contribution to the stability of dispersions of insoluble pigments and dyes containing polymer particles. However, the polymer particles containing a pigment or dye are not dissolved in water or an aqueous solution containing a water-soluble organic solvent, but are dispersed therein. Therefore, there is room for further improvement in that it is not completely stable under extreme temperatures and actual recording conditions, and that sedimentation of particles occurs over a long period of time. Moreover, this type of ink cannot be easily redispersed when a dry ink and a fresh ink are contacted.

In order to solve the above problems in an ink composed of water or an aqueous solution containing a water-soluble organic solvent and a water-soluble dye, an ink composition using a polymer resin soluble in alkali has been proposed. . Japanese Patent Publication No. 40-6581
The publication describes an ink composition containing a polymer resin containing a carboxylic acid functional group and a water-soluble basic dye. It is said that such an ink composition can give water resistance superior to that of an ink containing no polymer.

Japanese Unexamined Patent Publication (Kokai) No. 62-64875 and Japanese Patent Publication (Kokoku) No. 5-62633 disclose an ink composition containing a polymer resin having a sulfonic acid functional group and a water-soluble basic dye. ing. It is said that such an ink composition can provide better water resistance than an ink containing no polymer.

JP-A-5-230413 describes an ink composition containing a styrene polymer resin containing a carboxylic acid functional group and a water-soluble basic dye. The average molecular weight of the polymer used here is 150.
0 to 30000, and the acid value of the polymer is 150 to 300
It is. It is said that such an ink composition can provide better water resistance than an ink containing no polymer.

The alkali-soluble polymers used in these three examples are believed to contribute significantly to water resistance. However, the recorded image is not completely waterproof on all types of recording media. All of these conventional techniques leave room for improvement, and it can be said that there is still a need for an ink composition having excellent water resistance.

[0014]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink composition capable of forming a water-resistant recording image on paper regardless of the type of paper, and particularly an ink composition preferably used for ink jet recording. I am trying.

Another object of the present invention is to provide an ink composition in which a recorded image dries quickly.

The present invention further provides an ink composition which does not clog the nozzles of the recording head and does not cause ink droplets to be ejected in a curve that is not perpendicular to the recording head (no flying bow). It is an object.

Still another object of the present invention is to provide an ink composition which can easily redissolve the dried ink when the dried ink composition and the fresh ink composition are brought into contact with each other.

The ink composition according to the present invention comprises water, an alkali-soluble resin containing a phenol functional group, a basic dye, both the alkali-soluble polymer containing the phenol functional group and the basic dye. In which the amount of alkali is completely dissolved.

[0019]

DETAILED DESCRIPTION OF THE INVENTION The ink composition according to the present invention can be used in any of the ink jet recording methods known in the art in which the ink is ejected through a small diameter nozzle (generally a nozzle having a diameter of less than 50 microns). Can also be preferably used. The ink composition of the present invention also comprises
It is also possible to use it for a writing instrument such as a pen.

<Alkali-Soluble Resin Containing Phenol Functional Group> The alkali-soluble resin containing a phenol functional group used in the present invention is a mixture with water, and it should be dissolved in water when a certain amount of alkali is added. is necessary.

Alkali-soluble resins containing phenolic functional groups are commercially available from Arakawa Chemical Industry Co., Ltd. (Chuo-ku, Osaka City) under the trade name of Tamanoru in several different grades. Further, as the alkali-soluble resin containing a phenol functional group, several different grades are commercially available under the trade name of Dures from Sumitomo Dures Co., Ltd. (Chiyoda-ku, Tokyo).

<Basic Dye> The basic dye used in the present invention is, for example, Aizen Auramine OW 100.
(Brand name, Hodogaya Chemical Co., Ltd., CI Basic Yellow 2), Aizen Cathilon Yellow 3GLH (Brand name, Hodogaya Chemical Co., Ltd., CI Basic Yellow 11), Aizen Cathilon Brilliant Yellow 5G
LH (trade name, Hodogaya Chemical Co., Ltd., CI Basic Yellow 13), Aizen Cathilon Yellow GLH
(Product name, Hodogaya Chemical Co., Ltd., CI Basic Yellow 14), Aizen Cathilon Yellow 3RLH
(Trade name, manufactured by Hodogaya Chemical Co., Ltd., CI Basic Yellow 36), Baycolor Golden Yellow GLE 200
% (Trade name, manufactured by Bayer Co., Ltd.), Baycolor Yellow
8GLS 200% (trade name, manufactured by Bayer Co., Ltd.), Baycolor
Yellow 7GLL 200% (trade name, manufactured by Bayer Co., Ltd.),
Aizen Cathilon Orange GLH (trade name, Hodogaya Chemical Co., Ltd., CI Basic Orange 2), Aizen
Cathilon Orange RH (trade name, Hodogaya Chemical Co., Ltd., CI Basic Orange 22), Rhodamine
6G (Catalog number 25,243-3, Aldrich Japan
Company ,. Basic Red 1), Aizen Astra Phloxine F
F Concentrated (brand name, Hodogaya Chemical Co., Ltd., CI Basic Red 12), Aizen Cathilon
Pink FGH (trade name, manufactured by Hodogaya Chemical Co., Ltd., C.I.
I. Basic Red 13), Aizen Cathilon Brillia
nt Red4GH (trade name, Hodogaya Chemical Co., Ltd., C.I.
I. Basic Red 14), Aizen Cathilon Red GTL
(Trade name, manufactured by Hodogaya Chemical Co., Ltd., CI Basic Red 18), Aizen Cathilon Brilliant Pink
BH (trade name, Hodogaya Chemical Co., Ltd., CI Basic Red 36), Aizen Cathilon Brilliant Sca
rlet RH (trade name, manufactured by Hodogaya Chemical Co., Ltd., C.I.
I. Basic Red 37), Aizen Cathilon Red GL
H (trade name, Hodogaya Chemical Co., Ltd., CI Basic Red 38), Aizen Cathilon Red BLH (trade name, Hodogaya Chemical Co., Ltd., CI Basic Red 39), Aizen Cathilon Bordeaux RLH (Product name,
Hodogaya Chemical Co., Ltd., C.I. I. Basic Red 40), Baycolor Red 5BL 200% (trade name, manufactured by Bayer Co., Ltd.), Baycolor Red BBL 200% (trade name, manufactured by Bayer Co., Ltd.), Baycolor Red FBL 200% (trade name, manufactured by Bayer Co., Ltd.), Aizen Methyl Violet Pure Speci
al (trade name, manufactured by Hodogaya Chemical Co., Ltd., CI Basic Violet 1), Aizen Crystal Violet Ext
ra Pure (trade name, manufactured by Hodogaya Chemical Co., Ltd., C.I.
I. Basic Violet 3), Aizen Cathilon Red
6BH (trade name, manufactured by Hodogaya Chemical Co., Ltd., CI
Basic Violet 7), Aizen Rhodamine BH
(Product name, Hodogaya Chemical Co., Ltd., CI Basic Violet 10), Aizen Cathilon Brilliant R
ed 3BPH (trade name, manufactured by Hodogaya Chemical Co., Ltd., C.I.
I. Basic Violet 15), Aizen Cathilon V
iolet FRLH (trade name, manufactured by Hodogaya Chemical Co., Ltd.,
C. I. Basic Violet 25), Aizen Cathil
on Red 7BNH (product name, Hodogaya Chemical Co., Ltd.,
C. I. Basic Violet 27), Aizen Cathil
on Violet 3BLH (trade name, Hodogaya Chemical Co., Ltd., CI Basic Violet 28), Aizen Br
illiant Basic Cyanine 6GH (trade name, manufactured by Hodogaya Chemical Co., Ltd., CI Basic Blue 1), Aizen Ba
sic Pure Blue 5GH (trade name, Hodogaya Chemical Co., Ltd., CI Basic Blue 3), Aizen Victoria P
ure Blue BOH (trade name, manufactured by Hodogaya Chemical Co., Ltd.,
C. I. Basic Blue 7), Aizen Methylene Blue
FZ (Product name, Hodogaya Chemical Co., Ltd., CI Basic Blue 9), Aizen Methylene Blue BH Concen
trated (trade name, manufactured by Hodogaya Chemical Co., Ltd., C.I.
I. Basic Blue 9), Aizen Victoria Blue BH
(Brand name, Hodogaya Chemical Co., Ltd., CI Basic Blue 26), Aizen Marine Blue BNX (Brand name,
Hodogaya Chemical Co., Ltd., C.I. I. Basic Blue 28), Aizen Cathilon Blue 5GLH (trade name, Hodogaya Chemical Co., Ltd., CI Basic Blue 4)
5), Aizen Cathilon Blue 3RLH (trade name, Hodogaya Chemical Co., Ltd., CI Basic Blue 47),
Aizen Cathilon Navy Blue GLH (trade name, Hodogaya Chemical Co., Ltd., CI Basic Blue 64), Ai
zen Cathilon Blue GLH (trade name, Hodogaya Chemical Co., Ltd., CI Basic Blue 65), Aizen Cath
ilon Blue NBLH (brand name, Hodogaya Chemical Co., Ltd., CI Basic Blue 66), Aizen Cathilon
Blue NRLH (trade name, manufactured by Hodogaya Chemical Co., Ltd.,
C. I. Basic Blue 67), Aizen Cathilon Blu
e 2RLH (trade name, manufactured by Hodogaya Chemical Co., Ltd., CI
Basic Blue 68), Baycolor Blue 5GL 200%
(Product name, Bayer Co., Ltd.), Baycolor Blue F2RL
200% (trade name, manufactured by Bayer Co., Ltd.), Baycolor Blu
e BG 200% (trade name, manufactured by Bayer Co., Ltd.), Aizen Di
amond Green GH (trade name, manufactured by Hodogaya Chemical Co., Ltd., CI Basic Green 1), Aizen Malachit
e Green (trade name, manufactured by Hodogaya Chemical Co., Ltd., C.I.
I. Basic Green 4), Aizen Cathilon Brown 3
GLH (trade name, Hodogaya Chemical Co., Ltd., CI Basic Brown 11), Aizen Cathilon Red Brown 2
GLH (trade name, manufactured by Hodogaya Chemical Co., Ltd., CI Basic Brown 11) can be mentioned.

<Alkali> The alkali used in the present invention is not particularly limited as long as it dissolves the alkali-soluble resin containing a phenol functional group and the basic dye in the ink composition.

Examples of alkalis that can be preferably used in the present invention include inorganic bases and organic bases.

As the inorganic base, NaOH, KOH, L
Examples include iOH and CsOH. Examples of organic bases include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide.

<Ink Composition> The ink composition according to the present invention can form stable and water-resistant prints, provided that the following is a hypothesis and is not understood with the intention of limiting the present invention. The reason is considered as follows.

In the ink composition according to the present invention,
It is considered that the basic dye is attached to the alkali-soluble resin containing a phenol functional group by the attraction of both charges. As a result, it is considered that the coloring component can exist stably in the ink composition.

On the other hand, it is considered that the water resistance is exhibited on the recording medium for the following two reasons. First, the pH of domestic water is generally acidic. When this water adheres to the ink on the recording medium, a neutralization reaction occurs with the base in this ink. Secondly, the amount of water adhering to the recording medium is excessively large compared with the amount of ink on the recording medium. When diluted with a large amount of water, the basicity of the solution becomes weak.

Although it is difficult to separate the above two principles, in both cases, even if water adheres to the ink on the recording medium,
Since it is not possible to have sufficient basicity to redissolve the resin / dye in the ink, it is considered that high water resistance of the printed matter can be obtained.

The amount of the alkali-soluble resin containing a phenolic functional group in the ink composition depends on the type of polymer, the molecular weight of the polymer, and other ink components (dye, alkali, And if desired, it may be appropriately determined in consideration of additives used, for example, water-soluble monoalkyl ether of alkylene glycol or polyalkylene glycol, but it is preferably in the range of about 1 to 15% by weight. Within this range, a sufficient amount of dye can be solubilized to obtain a recorded image having an appropriate density, and even if an alkali-soluble resin containing a phenol functional group having a high molecular weight is used, a proper ink can be obtained. A viscosity is obtained. When used for inkjet recording, the amount of the alkali-soluble polymer containing a phenol functional group is preferably determined so that the viscosity of the ink composition is 10 cps or less at 20 ° C.

The basic dye is present in an amount of 0.05 to 3 parts by weight, more preferably 0.2 to 1.2 parts by weight, based on the weight of the alkali-soluble resin containing a phenol functional group. preferable.

The amount of the alkali is not particularly limited as long as it is an amount that completely dissolves the alkali-soluble polymer containing a phenol functional group and the basic dye, but is less than the minimum amount required to dissolve the polymer and the dye. Also, it is preferable that the amount of alkali is slightly excessive. To obtain greater ink stability, it is preferred that the amount of alkali is 10% or more over the minimum amount required to dissolve the polymer and dye.

The minimum amount of alkali required to dissolve the alkali-soluble resin containing phenolic functional groups and the basic dye depends on the optional additives such as water-soluble monoalkyl ethers of alkylene glycols or polyalkylene glycols. It is slightly affected by the amount. Therefore, when an optional additive is used, it is advantageous, but not limited to, that the additive is added before adding the alkali.

To the ink composition according to the present invention, a water-soluble monoalkyl ether of alkylene glycol or polyalkylene glycol can be added in order to give a recorded image quick drying property. By adding these, the drying property of printing can be improved. However, for some combinations of polymer and dye it is also possible to dry the recorded image sufficiently quickly without the addition of water soluble monoalkyl ethers of alkylene glycols or polyalkylene glycols.

As the water-soluble monoalkyl ether of alkylene glycol or polyalkylene glycol,
For example, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-i-propyl ether, ethylene glycol mono-n
-Butyl ether, ethylene glycol mono-s-butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-propyl ether, diethylene glycol mono-i-propyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol mono-s-butyl ether, Triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol mono-n-propyl ether, triethylene glycol mono-i-propyl ether, triethylene glycol mono-n-butyl ether, triethylene glycol mono-s-butyl ether , Propylene glycol monomethyl ether, and propylene Recall monoethyl ether. The amount of water-soluble monoalkyl ether of alkylene glycol or polyalkylene glycol is 1
-40% is preferable and 5-30% is more preferable.

The ink composition according to the present invention may further contain, in addition to the above components, a wetting agent such as glycerin, a bactericide, a surfactant, and other water-soluble resin that can be used for controlling the viscosity of the ink. it can.

The ink composition according to the invention is preferably prepared by first preparing a homogeneous mixture of a dye and an alkali-soluble resin containing phenolic functional groups and dissolving in water with a sufficient amount of alkali added. You can Prior to dissolving the homogeneous mixture in water, optional additives such as water-soluble monoalkyl ethers of alkylene glycols or polyalkylene glycols are added to the mixture, as this will generally further accelerate the dissolution. preferable.

Homogeneous mixtures of basic dyes and alkali-soluble resins containing phenolic functional groups can be prepared by various methods. One of the preferred methods is to mix the dye with an alkali-soluble resin containing phenolic functional groups at elevated temperature and high shear rate. The preferred temperature is higher than the softening point of the alkali-soluble resin containing a phenol functional group and lower than the decomposition temperature of the basic dye. High shear rates can be effected using mixing equipment designed for extrusion of plastics. Another preferred method is to dissolve both the polymer and dye in a mutually compatible volatile solvent and then spray dry the solution. Another method is to swell the polymer with a solvent in which the dye is soluble and the polymer is insoluble, but which is swellable. High temperatures and pressures can be used to increase the rate at which the dye penetrates the swollen polymer.

The ink composition according to the present invention is prepared by dissolving an alkali-soluble resin containing a phenol functional group in water in the presence of an alkali, adding a basic dye to the solution, and dissolving the basic dye. Good.

[0040]

The following examples further illustrate the invention.

Example 1 2.5 g of Aizen Cathilon Brilliant Yellow 5GLH 200% (product name, Hodogaya Chemical Co., Ltd.) in a stainless steel beaker was used as a phenol resin Tamanor PA (product name, Arakawa Chemical Industry Co., Ltd.). Made by company)
5 g. The mixture was vigorously stirred using a stainless steel spatula while heating the mixture at 180 ° C. for 10 minutes. After heating and mixing, a homogeneous, translucent, glassy mixture was obtained. After cooling to room temperature, glassy resin-dye material is crushed into small pieces, 100m
Transferred to 1 l sample bottle. 40% NaOH aqueous solution 3.1 g
And 79.4 g of ultrapure water was also placed in the sample bottle. The mixture was stirred at room temperature for 6 hours, during which time the glassy resin-dye material dissolved. 10 g of diethylene glycol monoethyl ether was added and the mixture was stirred for another hour.
The mixture was filtered through a 5 μm stainless steel mesh. The viscosity of this ink composition is 3.8 c at 20 ° C.
ps and pH was 12.3.

(Example 2) 2.5 g of Aizen Cathilon Yellow 7G-DP (trade name, manufactured by Hodogaya Chemical Co., Ltd.) in a beaker made of stainless steel was used as a phenol resin Tamanor P.
It was mixed with 5 g of A (trade name, manufactured by Arakawa Chemical Industry Co., Ltd.). The mixture was heated and mixed in the same manner as in Example 1 to obtain a homogeneous translucent, glassy mixture. In the same manner as in Example 1, the glassy resin-dye material was dissolved in 79.3 g of ultrapure water and 3.2 g of 40% NaOH aqueous solution. 10 g of diethylene glycol monomethyl ether was added and the mixture was stirred for another hour. The mixture was filtered through a 5 μm stainless steel mesh. The viscosity of this ink composition was 3.9 cps at 20 ° C., and the pH of the ink composition was 12.7.

Example 3 Aizen Cathilon Brilliant Pink CD-BH Concentrated in a stainless steel beaker
2.5 g (trade name, manufactured by Hodogaya Chemical Co., Ltd.) was mixed with 5 g of phenol resin Tamanoru PA (trade name, manufactured by Arakawa Chemical Industry Co., Ltd.). The mixture was heated to 190 ° C. and mixed as in Example 1 to obtain a homogeneous, translucent, glassy mixture. In the same manner as in Example 1, a glassy resin-dye material was dissolved in 80 g of ultrapure water and 2.5 g of 40% NaOH aqueous solution. 10 g of triethylene glycol mono-n-butyl ether was added and the mixture was further mixed with 1
Stirred for hours. The mixture was filtered through a 5 μm stainless steel mesh. The viscosity of this ink composition is 4.2 cps at 20 ° C., and the pH of the ink composition is 1
2.1.

Example 4 Aizen Astra Phloxine FF Concentrated (trade name, in a beaker made of stainless steel)
2.5 g of Hodogaya Chemical Co., Ltd.) 5 g of phenol resin Tamanoru PA (trade name, manufactured by Arakawa Chemical Co., Ltd.)
And mixed. The mixture was heated to 190 ° C. and mixed as in Example 1 to obtain a homogeneous, translucent, glassy mixture. In the same manner as in Example 1, 80.1 g of glassy resin-dye material and ultrapure water of 40% NaOH aqueous solution 2.4 were used.
g. 10 g of diethylene glycol mono-n-butyl ether were added and the mixture was stirred for another hour. The mixture was filtered through a 5 μm stainless steel mesh. The viscosity of this ink composition is 4.
It was 0 cps, and the pH of the ink composition was 12.2.

Example 5 In a stainless steel beaker, 2.5 g of Aizen Cathilon Red 7BH 200% (trade name, Hodogaya Chemical Co., Ltd.) was used as a phenol resin Tamanor P.
5 g of A (trade name, manufactured by Arakawa Chemical Industry Co., Ltd.) was mixed. Heat the mixture to 170 ° C. as in Example 1,
Mixed to obtain a homogeneous, translucent, glassy mixture. In the same manner as in Example 1, the glassy resin-dye material was dissolved in 79.7 g of ultrapure water and 2.8 g of 40% NaOH aqueous solution. 10 g of diethylene glycol mono-n-butyl ether were added and the mixture was stirred for another hour. 5μ
The mixture was filtered through m stainless steel mesh.
The viscosity of this ink composition is 3.5 cps at 20 ° C.
And the pH of the ink composition was 12.6.

(Example 6) 2.5 g of Aizen Cathilon Blue 5G-DP (trade name, manufactured by Hodogaya Chemical Co., Ltd.) in a stainless steel beaker was used as a phenol resin Tamanoru PA.
(Trade name, manufactured by Arakawa Chemical Industry Co., Ltd.) was mixed with 5 g.
The mixture was heated and mixed as in Example 1 to give a homogeneous, translucent, glassy mixture. In the same manner as in Example 1, the glassy resin-dye material was dissolved in 79.9 g of ultrapure water and 2.6 g of 40% NaOH aqueous solution. 10 g of diethylene glycol mono-n-butyl ether were added and the mixture was stirred for another hour. The mixture was filtered through a 5 μm stainless steel mesh. The viscosity of this ink composition was 4.2 cps at 20 ° C., and the pH of the ink composition was 12.1.

(Example 7) 2.5 g of Aizen Cathilon Pure Blue 5GH Concentrated (trade name, Hodogaya Chemical Co., Ltd.) in a stainless steel beaker was used as a phenol resin Tamanor PA (trade name, Arakawa Chemical Co., Ltd.). Made)
5 g. The mixture was heated and mixed as in Example 1 to give a homogeneous, translucent, glassy mixture.
In the same manner as in Example 1, the glassy resin-dye material was dissolved in 79.6 g of ultrapure water and 2.9 g of 40% NaOH aqueous solution. 10 g of diethylene glycol monoethyl ether was added and the mixture was stirred for another hour. 5 μm
The mixture was filtered through a stainless steel mesh of. The viscosity of this aqueous ink composition is 3.9 c at 20 ° C.
ps and the pH of the ink composition was 12.8.

(Example 8) 2.5 g of Aizen Brilliant Basic Cyanine 6GH (trade name, manufactured by Hodogaya Chemical Co., Ltd.) in a stainless steel beaker was used as a phenol resin Tamanor PA (trade name, manufactured by Arakawa Chemical Industry Co., Ltd.). ) 5 g. The mixture was heated and mixed as in Example 1 to give a homogeneous, translucent, glassy mixture. Example 1
In the same manner as described above, the glassy resin-dye material is added to ultrapure water 7
It was dissolved in 9.2 g and 3.3 g of 40% aqueous NaOH solution. 10 g of diethylene glycol mono-n-butyl ether were added and the mixture was stirred for another hour. 5 μm
The mixture was filtered through a stainless steel mesh of. The viscosity of this aqueous ink composition is 4.4 c at 20 ° C.
ps and the pH of the ink composition was 12.5.

Example 9 Aizen Cathilon Orange RH
2.5 g (trade name, Hodogaya Chemical Co., Ltd.) was dissolved in 47.5 g of ultrapure water while stirring. Phenolic resin Tamanor PA (trade name, manufactured by Arakawa Chemical Industry Co., Ltd.) 5
g and 40% NaOH aqueous solution 3.0 g, ultrapure water 32
g and stirred for 2 hours. Ethylene glycol mono-n-butyl ether 10 was added to this mixture under stirring.
g was added and the mixture was stirred for another hour. To this mixture under stirring was added the above colorant solution dropwise. After the addition was complete, the mixture was stirred for an additional 4 hours. The mixture was filtered through a 5 μm stainless steel mesh. The viscosity of this aqueous ink composition is 4.6 cps at 20 ° C.
And the pH of the ink composition was 12.5.

Example 10 Aizen Cathilon Brilliant
Scarlet RH (Product name, Hodogaya Chemical Co., Ltd.)
2.5 g was dissolved in 47.5 g of ultrapure water while stirring. Phenolic resin Tamanor PA (trade name, manufactured by Arakawa Chemical Industry Co., Ltd.) 5 g and 40% NaOH aqueous solution 3.1
g was added to 31.9 g of ultrapure water, and the mixture was stirred for 2 hours. To this mixture under stirring, diethylene glycol mono-
10 g of n-butyl ether were added and the mixture was stirred for another hour. To this mixture under stirring was added the above colorant solution dropwise. After the addition was complete, the mixture was stirred for an additional 4 hours. The mixture was filtered through a 5 μm stainless steel mesh. The viscosity of this aqueous ink composition is 20.
It was 4.1 cps at 0 ° C., and the pH of the ink composition was 12.8.

Example 11 Aizen Victoria Blue BH
2.5 g (trade name, Hodogaya Chemical Co., Ltd.) was dissolved in 47.5 g of ultrapure water while stirring. Phenolic resin Tamanor PA (trade name, manufactured by Arakawa Chemical Industry Co., Ltd.) 5
g and 2.9 g of 40% NaOH aqueous solution are added to ultrapure water 3
Added to 2.1 g and stirred for 2 hours. To this mixture under stirring was added 10 g of diethylene glycol mono-n-butyl ether and the mixture was stirred for another hour. To this mixture under stirring was added the above colorant solution dropwise. After the addition was complete, the mixture was stirred for an additional 4 hours. 5
The mixture was filtered through a μm stainless steel mesh. The viscosity of this aqueous ink composition was 4.0 cps at 20 ° C., and the pH of the ink composition was 12.2.

(Comparative Example 1) A styrene-acrylic acid resin JONCRYL 62 (trade name, manufactured by SC Johnson Polymer Co.) having a composition similar to that of the pigment type ink described in JP-A-5-230413 is included. A pigmented ink was produced. The composition of this pigment-based ink is JONCRYL 62 (21
%), Color Black SB-5 (7.1%, trade name, Degussa
Company), Neocol YSK (0.4%, trade name, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), ethylene glycol (6.5%), and ultrapure water (65%). The mixture was mixed for several hours to obtain a homogeneous mixture.

(Comparative Example 2) A water-soluble basic dye and a styrene-acrylic acid resin JONCRYL 680 (trade name, manufactured by SC Johnson Polymer Co.) having a composition similar to that of Example 8 of JP-A-5-230413 are used. An ink containing was produced. CI Basic Blue 12 instead of CI Basic Red 12
(Aizen Astra Phloxine FF Conc., Trade name, Hodogaya Chemical Co., Ltd.) was used. The composition of the ink containing this water-soluble basic dye is CI Basic Red 12 (2.5
%), JONCRYL 680 (7.5%), 28% ammonia solution (0.87%), triethanolamine (2.13)
%), Propylene glycol (15%), and ultrapure water (72%). The same manufacturing method as described in Example 8 of JP-A-5-230413 was used.

<Evaluation Test> The inks produced as described above were evaluated by the following tests.

1) Continuous Recording The ink composition sample was degassed and continuously recorded for 24 hours at 25 ° C. and 30% relative humidity using MJ-700V2C (trade name, manufactured by Seiko Epson Corporation). The weight of ejected ink per page was measured after 5 minutes and every 6 hours. The maximum sensitivity of the balance was 0.01 g. The results of this test show the following standard, that is, the standard deviation of 5 measurements is 0.
5 or less (◎), standard deviation of 5 measurements exceeds 0.5,
1.0 or less (○), the standard deviation of 5 measurements exceeds 1,
The evaluation was performed using a value of 1.5 or less (Δ), and a standard deviation of 5 measurements exceeding 1.5 (x).

2) Discontinuous recording An ink composition sample was degassed and recorded using a line pattern program using all nozzles of the recording head.
As the recording program, MJ-700V2C (trade name, manufactured by Seiko Epson Corporation) was used, and the recording program was executed at 25 ° C. and a relative humidity of 30% for 2 hours. The recording program used was a discontinuous program in which the operation of recording for 1 minute and then resting for 1 minute was repeated. During the rest period, the recording head was not covered to prevent the ink from drying. The sample recorded at the end of the 2 hour test was examined microscopically and evaluated according to the following criteria. That is, there was no evidence of clogging, all dots were observed at the last restart of the recording program (◎), there was slight clogging, and dots 1 to 5 were missing at the last restart of the recording program. Yes (○), there is considerable clogging, dots 6 to 20 are missing at the last restart of the recording program (△), there is unacceptable clogging, and dots are missing at the last restart of the recording program. 21 or more was lacking (x), and it evaluated as.

3) Solid Printing Drying Rate Using a program for degassing an ink composition sample and recording a rectangular block of 1 cm × 7.2 cm with solid printing of the highest density, Xerox P paper (trade name, Fuji Xerox Co., Ltd. Manufactured). The sample was recorded using MJ-700V2C (trade name, manufactured by Seiko Epson Corporation). Immediately after the block was recorded, the time until the glossy, light-reflecting liquid ink completely disappeared was measured. Evaluation was performed using the following criteria: 1 second or less (⊚), 1 second or more, 2 seconds or less (◯), 2 seconds or more, 5 seconds or less (Δ), 5 seconds or more (x). .

4) Redissolution / Redispersion of dried ink 1 μl of an ink sample was put into a Teflon block (15 mm × 10).
mm × 1 mm) and left to dry at room temperature for 24 hours. The sample was further dried at 40 ° C. for 72 hours. next,
The Teflon block with the sample was immersed in 20 ml of the original ink composition. After 1 hour, the pieces were taken out and inspected using tweezers. If some of the dried ink remained on the Teflon block, the sample was reconstituted in the original ink composition. 1) soaking, 2) removing, and 3)
The test sequence was repeated at 1 hour intervals for up to 5 hours or until there was no evidence of sample remaining on the Teflon block. Evaluation was made using the following criteria: 1 hour or less (⊚), 1 hour or more, 2 hours or less (◯), 2 hours or more, 4 hours or less (Δ), 4 hours or more (x). .

5) Water resistance of recorded sample A sample of the ink composition was degassed, and Xerox P and R paper (trade name, Fuji Xerox Co., Ltd.) was used using MJ-700V2C (trade name, manufactured by Seiko Epson Corporation). Manufactured) and characters and figures were recorded. The recorded sample was left to dry for 24 hours. A drop of water (0.05 ml each drop) was then carefully placed over both the recorded letters and graphics. The moistened sample was dried for 24 hours. The water resistance of the recorded image was evaluated according to the following criteria, that is, the two types of paper showed no change in the moistened recording sample with respect to both the characters and the graphics (⊚), 2 With the paper of the type, the moistened recording sample did not change with respect to the characters, but showed slight fading and / or bleeding with respect to the solid print pattern with the highest density (○), and the moistened recording sample showed with respect to the characters. Shows that only one type of paper has not changed, but with regard to the solid print pattern with the highest density, both types of paper show slight fading and / or bleeding (△). Indicates fading and / or bleeding (x), and was evaluated.

The inks of the above Examples and Comparative Examples according to the present invention were evaluated by the above test method. The result is the first
It was as shown in the table.

[0061]

[Table 1]

Claims (8)

[Claims] 1. Water, an alkali-soluble resin containing a phenol functional group, a basic dye, and both the alkali-soluble polymer containing the phenol functional group and the basic dye are completely dissolved in the ink composition. An ink composition comprising an amount of alkali. 2. The ink composition according to claim 1, wherein the basic dye is contained in an amount of 0.05 to 3 parts by weight based on the alkali-soluble resin containing the phenol functional group. 3. The ink composition according to claim 1, further comprising a water-soluble monoalkyl ether of alkylene glycol or polyalkylene glycol. 4. The ink has a viscosity of 10 cp at 20 ° C.
The ink composition according to any one of claims 1 to 3, which is less than s and is used for inkjet recording. 5. The amount of the alkali-soluble resin containing a phenol functional group is 1 to 15% by weight, and the amount of the basic dye is 0.2 to 1.2% by weight based on the weight of the alkali-soluble resin containing a phenol functional group. The ink composition according to any one of claims 1 to 4, which is a part. 6. Further, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether,
The ink composition according to any one of claims 1 to 5, further comprising a water-soluble monoalkyl ether of alkylene glycol or polyalkylene glycol selected from a mixture thereof. 7. The method for producing the ink composition according to claim 1, wherein the alkali-soluble resin containing a phenol functional group and the basic dye are higher than the softening point of the polymer. , Mix at a temperature lower than the decomposition temperature of the dye,
A method comprising dissolving the resulting mixture of polymer and dye in water with an alkali-soluble resin containing phenolic functional groups and an amount of alkali that completely dissolves the basic dye. 8. The method for producing the ink composition according to claim 1, wherein the alkali-soluble resin containing a phenol functional group is dissolved in water in the presence of an alkali, and the basic dye is further added. A method comprising lysing.