JPH10204343A - Ink jet ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an ink jet ink that enables reading with the naked eye or with a detector using near-infrared rays and that is water-resistant on paper, by incorporating C.I. Sulfur Black 1 made water-soluble by substituting its hydroxyl group with a carboxyl group and an amine salt of a C.I. Direct Black 154-epoxide compd. adduct as colorants into the same. SOLUTION: C.I. Sulfur Black 1 having at least one hydroxyl group substd. with a free carboxyl group is used in an amt. of 2-5wt.% of the ink in order to obtain the delivery stability and the concn. enough to enable the reading with a detector using near-infrared rays. The amine salt of a C.I. Direct Black- epoxide compd. adduct, prepd. by reacting C.I. Direct Black with methyl glycidyl ether, etc., and then with diphenylguanidine, etc., is used in an amt. of 1-6wt.% of the ink. The ink pref. further contains butyl carbitol, a water-soluble solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink-jet ink which has sufficient absorption in the near infrared region and the visible region and has excellent water resistance.

[0002]

2. Description of the Related Art Heretofore, as an ink jet ink having absorption in a near infrared region and a visible region, a solution in which a water-soluble nigrosine dye is dissolved in water and an aqueous solvent has been often used. However, there is a problem that the water resistance of the ink-jet recorded matter is poor, and if water is spilled, bleeding of the dye in the recorded portion easily occurs. In order to improve such poor water resistance, JP-A-53-135707 discloses an ink-jet ink using thiosulfonated CI sulfur black 1 as an aqueous dye having absorption in the near infrared region. I have. However, this ink has a problem that the recorded matter becomes light gray and the sense of density is insufficient.

Further, an ink jet ink in which a carbon black pigment having absorption in a near infrared region and a visible region is dispersed in an aqueous medium has been developed. However, unlike an aqueous dye, a carbon black pigment does not dissolve in an aqueous medium, and it is very difficult to disperse it as fine particles and to stably maintain a dispersed state. While exhibiting the characteristics of pigments with excellent water resistance and light resistance, the quality of ink, such as adjustment to ejection conditions, long-term storage stability, fixing to recording media such as paper, image color, bleeding, etc. At present, further improvements are required to obtain properties comparable to or better than dyes.

[0004]

SUMMARY OF THE INVENTION The object of the present invention is to
A dye-dissolving type ink-jet ink that can be read by a detector using near-infrared light near 0 nm and the naked eye and has sufficient water resistance on paper such as copy paper and high-quality paper where relatively water resistance is difficult to obtain. To provide.

[0005]

Means for Solving the Problems The present inventors have proposed that near-infrared rays can be obtained by using water-soluble CI sulfur black 1 and an amine salt of CI direct black 154 to which an epoxide compound is added as coloring agents. The present inventors have found that an ink-jet ink having sufficient absorption in the region and the visible region and having excellent water resistance can be obtained, and the present invention has been accomplished.

[0006] That is, the present invention relates to a water-soluble CI sulfur black 1 and a CI to which an epoxide compound is added.
An ink jet ink comprising an amine salt of Direct Black 154 as a colorant. The present invention also relates to the above ink jet ink, wherein the water-soluble CI sulfur black 1 is a free acid type CI sulfur black 1 in which at least one hydroxyl group of the CI sulfur black 1 is substituted with a carboxyl group.

Further, the present invention further provides a cellosolve system,
The present invention relates to the above ink jet ink, comprising at least one aqueous solvent selected from carbitol type and pyrrolidone type. Further, the present invention relates to the above ink jet ink, which contains butyl carbitol. In addition, the present invention relates to an amine salt of CI direct black 154 containing 2 to 5% by weight of CI sulfur black 1 dissolved in water and an epoxide compound.
% By weight, at least one aqueous solvent selected from cellosolves, carbitols and pyrrolidones
The present invention relates to the above ink jet ink, comprising 0% by weight and 70 to 96.5% by weight of water.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The water-soluble CI sulfur black 1 according to the present invention is a dye having water resistance and has absorption in the near infrared region. CI Sulfur Black 1 is known as a mixture of a dye represented by the following structural formula (1) and a dye represented by the following structural formula (2).

[0009]

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[0010]

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As the water-soluble CI sulfur black 1, a free acid CI sulfur black 1 in which at least one hydroxyl group of CI sulfur black 1 is substituted with a carboxyl group, a thiosulfonic acid group or a sulfonic acid group is used.
Is used. Above all, the free acid type CI sulfur black 1 in which at least one hydroxyl group of CI sulfur black 1 is substituted with a carboxyl group is suitably used because it has a suitable water solubility and excellent water resistance. . It is preferable to use 2% by weight or more of the CI water-solubilized CI sulfur black in the ink in order to obtain a concentration sufficient for reading by a detector using near infrared rays. It is preferable that the amount of the water-soluble CI sulfur black 1 in the ink does not exceed 5% by weight in order to prevent an increase in viscosity and to obtain sufficient ejection stability.

The amine salt of CI Direct Black 154 to which the epoxide compound is added in the present invention (hereinafter referred to as C.I.
I. Abbreviated as direct black 154 derivative. ) Is used to supplement the apparent density of the water-soluble CI sulfur black 1 on paper, and the CI of the following structural formula (3) is used.
This is one in which the water resistance of Direct Black 154 is further improved.

[0013]

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The CI Direct Black 154 derivative is
It is obtained by salting an addition compound obtained by reacting CI Direct Black 154 with an epoxide compound with an amine compound, or by reacting a compound obtained by salting CI Direct Black 154 with an amine compound with an epoxide compound. As the epoxide compound, glycidyl ether type epoxide compounds and alkylene oxides are used. Examples of the glycidyl ether type epoxide compound include methyl glycidyl ether and butyl glycidyl ether. Examples of the alkylene oxides include ethylene oxide, propylene oxide, glycidol, and 1,2-butylene oxide. Examples of the amine compound used for salt formation include amine compounds such as diphenylguanidine, 2-ethylhexylamine, cyclohexylamine, dicyclohexylamine, diethylurea, tetraethylurea, trimethylthiourea, diphenylthiourea, tolylguanidine and tolylbiguanide.

The reaction between CI Direct Black 154 and an epoxide compound is carried out in the presence or absence of a catalyst.
The reaction is carried out at room temperature or preferably in a solvent. When an epoxide compound having a low boiling point is used, the reaction may be a pressurized reaction using an autoclave. The epoxide compound allows one to four epoxides to bind to one molecule of CI Direct Black 154. The epoxide adduct may be isolated after the reaction, or may be directly salted with the amine compound without isolation.

The reaction of a compound obtained by salting CI Direct Black 154 with an amine compound and an epoxide compound can be carried out in the same manner. In this method, the epoxide compound reacts with both the CI Direct Black 154 and the active hydrogen of the salt-forming amine, so that a CI Direct Black 154 derivative having good water resistance is obtained. Obtained in this way
CI Direct Black 154 derivative contains 1
It is preferable to use it in the range of 6% by weight. If the amount is less than 1% by weight, the image density and color reproduction will be insufficient. On the other hand, when the content is more than 6% by weight, the stability of the discharge is remarkably reduced, so that clogging of the nozzle is apt to occur frequently, and it is difficult to adjust the viscosity of the ink.

The ink-jet ink of the present invention is characterized in that
A black dye is contained as a colorant, but when used together with at least one aqueous solvent selected from cellosolves, carbitols and pyrrolidones, particularly butyl carbitol, which dissolves the black dye, strong water resistance is obtained. Is preferred. At least one aqueous solvent selected from cellosolves, carbitols and pyrrolidones is preferably used in the ink in a range of 0.5 to 10% by weight. If the amount is less than 0.5% by weight, it does not penetrate the paper sufficiently, and it is difficult to obtain good water resistance. If the content is more than 10% by weight, the permeation becomes excessive and print-through occurs. Examples of the cellosolve-based aqueous solvent include methyl cellosolve, ethyl cellosolve, and butyl cellosolve. Examples of the carbitol-based aqueous solvent include butyl carbitol, ethyl carbitol and the like. Examples of the pyrrolidone-based aqueous solvent include N-methyl-2-pyrrolidone.

The ink-jet ink of the present invention generally comprises 2 to 5% by weight of CI sulfur black 1 in water, 1 to 5% by weight of an amine salt of CI Direct Black 154 to which an epoxide compound is added, cellosolve, carbitol. 10 to 10% by weight of at least one aqueous solvent selected from the group consisting of
Consists of 6.5% by weight. As the water, ion-exchanged water or distilled water from which metal ions and the like have been removed is suitably used.

The ink-jet ink of the present invention contains, in addition to the above components, an antifungal agent, another aqueous solvent, a chelating agent,
Conditioning agents, defoamers, surfactants and the like can be added. The fungicide prevents the generation of mold and microorganisms in the ink, and is preferably used in the ink in the range of 0.03 to 1.0% by weight. Examples of the fungicides include sodium dehydroacetate, sodium benzoate, sodium pyridinethione-1-oxide, zinc pyridinethione-1-oxide, 1,2-benzisothiazolin-3-one, 1-
And amine salts of benzisothiazolin-3-one.

The other aqueous solvent prevents drying and solidification of the ink at the nozzle portion, prevents stable ink jetting and prevents the nozzle from drying over time, and also functions as a humectant. And used in the range of 0 to 25% by weight in the ink. Other aqueous solvents include ethylene glycol, diethylene glycol, propylene glycol, triethylene glycol, polyethylene glycol,
Glycerin, tetraethylene glycol, dipropylene glycol, ketone alcohol, 1,2-hexanediol, 2,4,6-hexanetriol, tetrafurfuryl alcohol, 4-methoxy-4-methyl petanone and the like can be mentioned. Further, alcohols such as methanol, ethanol and isopropyl alcohol can be used for the purpose of speeding up the drying of the ink on paper.

The chelating agent blocks the metal ions in the ink and prevents the deposition of metal at the nozzle portion and the deposition of insoluble substances in the ink. The chelating agent includes ethylenediaminetetraacetic acid, ethylenediaminetetraethylene, and the like. A sodium salt of acetylic acid, a diammonium salt of ethylenediaminetetraacetic acid, a tetraammonium salt of ethylenediaminetetraacetic acid, and the like are used. These are used in the ink in the range of 0 to 0.5% by weight.

Further, in order to adjust the pH of the ink and obtain the stability of the ink or the stability with the ink piping in the recording apparatus, a pH adjuster such as an amine, an inorganic salt or ammonia, or a buffer solution such as phosphoric acid is used. be able to. Further, an antifoaming agent can be added in order to prevent the circulation and movement of the ink or the generation of bubbles during the production of the ink. Furthermore, with the aim of improving ink stability and image quality, anionic,
Surfactants such as nonionic, cationic and zwitterionic surfactants can be used.

Examples of the anionic activator include fatty acid salts, alkyl sulfate salts, alkyl aryl sulfonates, alkyl naphthalene sulfonates, dialkyl sulfonates, dialkyl sulfosuccinates, alkyl diaryl ether disulfonates, and alkyl phosphoric acids. Salt, polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl aryl ether sulfate, naphthalenesulfonic acid formalin condensate, polyoxyethylene alkyl phosphate ester salt, glycerol borate fatty acid ester, polyoxyethylene glycerol fatty acid ester, etc. No.

Examples of the nonionic activator include polyoxyethylene alkyl ether, polyoxyethylene alkyl aryl ether, polyoxyethylene oxypropylene block copolymer, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, Nonionic activators such as glycerin fatty acid ester, polyoxyethylene fatty acid ester, polyoxyethylene alkylamine, fluorine-based, and silicon-based are exemplified.

Examples of the cationic activator include an alkylamine salt, a quaternary ammonium salt, an alkylpyridinium salt, an alkylimidazolium salt and the like. Examples of zwitterionic activators include alkyl betaines, alkylamine oxides, phosphadylcholines and the like. Further, additives such as urea and dimethyl urea, and various other conventionally known solvents, additives, salts, synthetic resins, and natural resins can also be added to the inkjet ink of the present invention.

The ink jet ink of the present invention is obtained by converting water-soluble CI sulfur black 1 and an amine salt of CI direct black 154 to which an epoxide compound has been added from water and, if necessary, a cellosolve, a carbitol or a pyrrolidone. It can be produced by mixing with at least one selected aqueous solvent, and adding other additives as necessary to sufficiently dissolve. The inkjet ink of the present invention is sufficiently filtered through a filter having a pore size of 3 μ or less, preferably a filter having a pore size of 1.0 μ or less, and more preferably a filter having a pore size of 0.45 μ or less.
Prior to filtration, filtration by centrifugation may be performed, thereby reducing clogging in filter filtration and reducing filter replacement.

The ink is prepared as a liquid having a viscosity of 0.8 to 15 cps (at 25 ° C.), depending on the type of the recording apparatus. The surface tension is 25-60 dyn / cm. pH
Is in the range of 7 to 12, though not particularly restricted, and is in the range of 7 to 1
A weak alkalinity of 0 is preferred. The ink of the present invention can be used for both a continuous type printer and an on-demand type printer. In a continuous type printer, the conductivity of the ink is adjusted so that the droplets are appropriately charged.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.
In the examples, parts and% represent parts by weight and% by weight, respectively. (Synthesis Example 1) To 180 parts of water, 13 parts (0.1 mol) of butyl glycidyl ether was added. Then, 77 parts (0.1 mol) of CI Direct Black 154 was added and mixed well.
Was reacted. After the reaction, it was left at room temperature and cooled. A solution in which 10 parts of 1-O-tolylbiguanide was dissolved in a solution in which 5 parts of hydrochloric acid was dissolved in 100 parts of water was added dropwise thereto. After the dropwise addition, the pH was adjusted to 3.0 with hydrochloric acid, and the temperature was raised to 40 ° C. The resulting black precipitate was filtered out and washed with water to give CI Direct Black 154 derivative.

(Synthesis Example 2) 77 parts (0.1 mol) of CI Direct Black 154 was added to 400 parts of water, and the mixture was dissolved by heating to 70 ° C to prepare a dye solution. 1,3-Diphenylguanidine 1 in a solution of 9 parts of sulfuric acid in 50 parts of water
0.6 part (0.05 mol) was dissolved and added dropwise to the previously prepared dye solution at 25 ° C. After dropping, the pH was adjusted to 3.0 with hydrochloric acid.
And then heated to 40 ° C. The resulting precipitate was collected by filtration and dried to obtain a diphenylguanidine adduct of CI Direct Black 154. Water 1
To 50 parts were added 13 parts (0.1 mol) of butyl glycidyl ether, and then 85 parts (0.1 mol) of a diphenylguanidine adduct of CI Direct Black 154 were added. After stirring at room temperature for 60 minutes, 13 parts of triethanolamine was added. Was added thereto, and the temperature was gradually raised to cause a reaction at 80 ° C. The reaction mixture was precipitated with 3% aqueous sulfuric acid, filtered, washed and taken out.
A direct black 154 derivative was obtained.

(Synthesis Examples 3 to 7) CI Direct Black 154 derivative was obtained in the same manner as in Synthesis Example 1 except that the epoxide compound and the amine compound were changed to the compounds shown in Table 1.

[0031]

[Table 1]

Example 1 The following materials were placed in a dissolution vessel, mixed and dissolved, and then filtered through a 0.45 μm membrane filter to produce an ink jet ink. Free acid type CI sulfur black 1 having a carboxyl group 4.0 parts CI direct black 154 derivative of Synthesis Example 1 1.0 part N-methyl-2-pyrrolidone 4.0 parts Triethanolamine 0.5 part Fungicide ( "Sodium Omazine" manufactured by Ohrin Co.) 0.15 parts Sodium salt of ethylenediaminetetraacetic acid 0.02 parts Purified water 91.33 parts

Example 2 The following materials were placed in a dissolution vessel, mixed and dissolved, and then filtered through a 0.45 μm membrane filter to produce an ink jet ink. Free acid type CI sulfur black 1 having thiosulfonic acid group 1 4.0 parts CI Direct Black 154 derivative of Synthesis Example 2 1.3 parts Butyl cellosolve 4.0 parts Triethanolamine 0.5 parts Fungicide (proxel manufactured by Zeneca Corporation) GXL ") 0.15 parts Ethylenediaminetetraacetic acid sodium salt 0.02 parts Purified water 91.33 parts

Examples 3 to 7 The following materials were placed in a dissolution vessel, mixed and dissolved, and then filtered through a 0.45 μm membrane filter to produce an ink jet ink. Free acid type CI sulfur black 1 having a carboxyl group 4.0 parts CI direct black 154 derivative of Synthesis Examples 3 to 1.5 1.5 parts Butyl carbitol 4.0 parts Ethylene glycol 1.0 part Fungicide (manufactured by Ohlin Co., Ltd.) "Sodium omazine") 0.15 parts Sodium salt of ethylenediaminetetraacetic acid 0.02 parts Purified water 90.33 parts

Comparative Example 1 The following ingredients were placed in a dissolution vessel, mixed and dissolved, and filtered with a 0.45 μm membrane filter to produce an ink jet ink. CI Direct Black 154 4.0 parts Ethylene glycol 4.0 parts Triethanolamine 0.5 parts Antifungal agent ("Proxel GXL" manufactured by Zeneca) 0.15 parts Ethylenediaminetetraacetic acid sodium salt 0.02 parts Purified water 91.03 parts

Comparative Example 2 The following materials were placed in a dissolution vessel, mixed and dissolved, and then filtered through a 0.45 μm membrane filter to produce an ink jet ink. CI Acid Black 2 (water-soluble nigrosine dye) 4.0 parts Butyl carbitol 4.0 parts Triethanolamine 0.5 parts Antifungal agent ("Sodium Omazine" manufactured by Ohlin Co.) 0.15 parts Ethylenediaminetetraacetic acid sodium salt 0.02 parts Purified water 91.03 parts

Comparative Example 3 The following materials were placed in a dissolving vessel, mixed and dissolved, and then filtered through a 0.45 μm membrane filter to produce an ink jet ink. Free acid CI sulfur black having a thiosulfonic acid group 1 4.0 parts Butyl carbitol 4.0 parts Triethanolamine 0.5 parts Antifungal agent (“Sodium Omazine” manufactured by Ohlin Co.) 0.15 parts Ethylenediaminetetraacetic acid Sodium salt 0.02 parts Purified water 91.03 parts

The inks obtained in Examples and Comparative Examples were evaluated for water resistance, resolubility, filterability, viscosity, jetting characteristics, and the like. Table 2 shows the results. When the ink obtained in the example was stored at −40 ° C. for one week and then naturally thawed, the initial viscosity was maintained and stable ejection characteristics were exhibited. When stored in a thermostat at 60 ° C. for one month, the initial viscosity was maintained and stable injection characteristics were exhibited. Further, when a cycle of −40 ° C. for 7 hours, room temperature for 7 hours, and 50 ° C. for 7 hours was repeated three times, the initial printing characteristics and the physical properties of the ink were maintained.

The evaluation was performed as follows. (1) Water resistance After printing the ink on the cartridge of an inkjet printer (“GXII” manufactured by Hitachi, Ltd.) and printing on plain paper (“K” manufactured by Xerox Corporation), immerse the ink in water for 1 minute after drying. Was visually evaluated (○: no bleeding, ×: bleeding). In addition, solid printing was performed, and the rate of change in reflection density after immersing the printed matter in water for 1 minute was measured.
The reflection density after immersion / reflection density before immersion was expressed in%. Further, the change of the printed portion when the solid printed on the art paper was rubbed three times with a wet cotton swab was visually evaluated (（: no change, Δ: slight change, x: change).

(2) Redissolvability The ink was dropped on a nickel plate, and after 2 days of drying, the solubility when immersed in the same ink was visually evaluated (○: dissolution, Δ: time required for dissolution, × : Insoluble). (3) Filterability The number of filters required when filtering 500 ml of ink with a 42 mm diameter membrane filter was examined (（: 1 sheet, Δ: 2 sheets). (4) Viscosity 25 ° C with a vibrating viscometer (“VM-1A” manufactured by Yamaichi Electric Co., Ltd.)
Was measured.

(5) Ejection Characteristics Injection failure of nozzles during continuous printing was evaluated based on the presence or absence of a defect in the printed matter (物: no defect, ×: defective). (6) The PCS concentration near 900 nm absorption in the near infrared region was measured by Macbeth PCM-2. (7) Absorption in the visible region The black feeling was visually evaluated (○: good, ×: slightly thin).

[0042]

[Table 2]

[0043]

The ink-jet ink of the present invention has 90
It can be read by a detector using near-infrared light near 0 nm and the naked eye, and has sufficient water resistance on paper, such as copy paper and high quality paper, where relatively water resistance is difficult to obtain. Further, the ink-jet ink of the present invention is excellent in re-dissolving property of the ink in the head, and has good ejection stability in the nozzle. Therefore, it can be suitably used in fields such as cardboard marking and numbering.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tsutomu Fujigamori 2-13-13 Kyobashi, Chuo-ku, Tokyo Toyo Ink Manufacturing Co., Ltd.

Claims (5)

[Claims] 1. A water-soluble CI sulfur black 1,
CI Direct Black 1 with epoxide compound added
54. An ink-jet ink comprising: 54 amine salt as a colorant. 2. A water-soluble CI sulfur black 1 comprising:
2. The ink jet ink according to claim 1, which is a free acid type CI sulfur black 1 in which at least one hydroxyl group of CI sulfur black 1 is substituted with a carboxyl group. 3. The ink-jet ink according to claim 1, further comprising at least one aqueous solvent selected from cellosolves, carbitols and pyrrolidones. 4. The ink-jet ink according to claim 1, further comprising butyl carbitol. 5. A method according to claim 1, wherein water-soluble CI sulfur black 1 is mixed with 2
-5% by weight, 1-5% by weight of amine salt of CI Direct Black 154 to which an epoxide compound is added, 0.5-10% by weight of at least one aqueous solvent selected from cellosolves, carbitols and pyrrolidones, and water 7
The inkjet ink according to claim 3, comprising 0 to 96.5% by weight.