JP3374605B2 - Recording liquid - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a recording liquid. Specifically, it relates to a recording liquid suitable for inkjet recording.

[0002]

2. Description of the Related Art A so-called ink jet recording method has been put into practical use in which droplets of a recording liquid containing a water-soluble dye such as a direct dye or an acid dye are ejected from a minute ejection orifice to perform recording. Regarding this recording liquid, it is fast to fix to general recording paper for general office work such as PPC (plain paper copier) paper such as electrophotographic paper, fan hold paper (continuous paper such as computers), and printing of printed matter It is required that the quality is good, that is, the print has no bleeding and the contour is clear, and that the stability during storage as a recording liquid is also excellent. Significantly limited.

On the other hand, dyes for recording liquids have sufficient solubility in the above-mentioned limited solvents and are stable even when stored as recording liquids for a long period of time.
Further, although it is required that the printed image has a high density and is excellent in water resistance and light resistance, it has been difficult to satisfy many of these requirements at the same time. Therefore, various methods (for example, JP-A-55-144067, JP-A-55-152747, and JP-A-57-207660) are used.
JP-A-59-226072, JP-A-61-277.
6, JP-A-61-57666, JP-A-62-190.
269, JP-A-62-190271, JP-A-62-1902
190272, JP-A-62-197476, JP-A-62-250082, JP-A-62-246975,
JP-A-62-256974, JP-A-62-28865
9, JP-A-63-8463, JP-A-63-2286.
7, JP-A-63-117079, and JP-A-63-30.
567, JP-A-63-33484, JP-A-63-6.
3764, JP-A-63-105079, JP-A-64
-31877, JP-A-1-93389, JP-A-1-
210464, JP-A-1-240584, JP-A-2
-16171, JP-A-2-140270, JP-A-3
No. 2008082, JP-A-5-262998, etc.) have been proposed, but they have not yet fully satisfied the market demand.

Further, in British Patent (GB) 2251625 and Japanese Patent Publication No. 6-504562, it is described that a dye having a structure similar to that of the present invention can be used for ink jet recording. However, these dyes have a structure in which three naphthalene rings are linked via two azo groups, and a dye having such a structure tends to be bronze, and a sufficient color density tends not to be obtained.

[0005]

DISCLOSURE OF THE INVENTION The present invention has good print quality even when recorded on plain paper for ink jet recording, writing, etc., and has a high density of recorded images, light resistance and especially water resistance. It is an object of the present invention to provide a black recording liquid which has excellent properties and color tone of a recorded image and has good stability when stored for a long period of time.

[0006]

The present inventor has accomplished the present invention by confirming that the above object is achieved when a specific dye is used as a recording liquid component. That is, the gist of the present invention resides in a recording liquid containing an aqueous medium and at least one of the dyes represented by the general formula [I] in the form of the free acid in claim 1.

The present invention will be described in detail below. The dye used in the present invention has a free acid form represented by the general formula [I] in claim 1. In the general formula [I], R
₁ represents H, CH ₃ , an OCH ₃ group or a group represented by the general formula [II], preferably an OCH ₃ group or a general formula [I]
I], and more preferably an OCH ₃ group or a group of the general formula [II] in which X is —CO—.

When R ₁ represents a H, CH ₃ or OCH ₃ group, R ₂ represents a H, CH ₃ or OCH ₃ group, but preferably an OCH ₃ group. When R ₁ represents a group represented by the general formula [II], R ₂ is H, a substituted or unsubstituted alkyl group having 1 to 9 carbon atoms, or a substituted or unsubstituted alkoxy group having 1 to 9 carbon atoms. Group, preferably a substituted or unsubstituted alkoxy group having 1 to 9 carbon atoms.

Examples of the substituent of the alkyl group represented by R ₂ include a phenyl group and the like, and examples of the substituent of the alkoxy group include an alkoxy group, a hydroxyl group, a hydroxyalkoxy group, a phenyl group, a -COOH group and a -COOH.
Examples thereof include an alkoxy group substituted with a group. R ₃ represents H, a phenyl group optionally substituted with a —SO ₃ H group or a —COOH group, or an alkyl group having 1 to 3 carbon atoms substituted with a —COOH group, and R ₄ is H or — C
It represents an alkyl group having 1 to 3 carbon atoms substituted with an OOH group, and when R ₄ represents H, R ₃ is preferably H
Alternatively, when R ₄ represents a phenyl group which may be substituted with —SO ₃ H group or —COOH group, and R ₄ represents an alkyl group having 1 to 3 carbon atoms which is substituted with —COOH group, R ₃ is preferably Represents an alkyl group having 1 to 3 carbon atoms which is substituted with H or —COOH group.

In the general formula [II], the aryl group having 6 to 12 carbon atoms represented by R ₅ is an unsubstituted aryl group such as a phenyl group or a naphthyl group, a phenyl group having a substituent such as an alkyl group, or a naphthyl group. A substituted aryl group such as a group (the total number of carbon atoms of the substituent and the aryl group is 6 to
12). The dye used in the present invention may be used as it is in the free acid form represented by the general formula [I], or may be used as it is when it is obtained in a salt form at the time of production, or may be used in a desired salt form. May be converted to Further, a part of the acid group may be a salt type, and a salt type dye and a free acid type dye may be mixed. Examples of such a salt type include salts of alkali metals such as Na, Li and K, alkyl groups,
Examples thereof include ammonium salts which may be substituted with a hydroxyalkyl group and organic amine salts. Examples of organic amines include lower alkylamines, hydroxy-substituted lower alkylamines, carboxy-substituted lower alkylamines, and polyamines having 2 to 10 alkyleneimine units having 2 to 4 carbon atoms. For these salt forms,
The kind of the salt is not limited to one kind, and a plurality of kinds of salts may be contained in one molecule of the dye, or dyes having different salt types may be mixed. Specific examples of these dyes include, for example, Nos. 1-No. An azo dye having a structure shown in 21 is mentioned.

[0011]

[Chemical 3]

[0012]

[Chemical 4]

[0013]

[Chemical 5]

[0014]

[Chemical 6]

The azo dye represented by the general formula [I] can be obtained by a method known per se [for example, Yutaka Hosoda, "New Dye Chemistry" (published by Gihodo, December 21, 1973) Nos. 396-409.
Refer to page], and can be manufactured through the diazotization and coupling steps. The content of the dye of the general formula [I] in the recording liquid is preferably 0.5 to 5% by weight, more preferably 2 to 4% by weight, based on the total amount of the recording liquid.

The aqueous medium used in the present invention includes water and water-soluble organic solvents such as ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol (weight average molecular weight (Mw) = 190-4).
00), glycerin, N-methylpyrrolidone, N-ethylpyrrolidone, 1,3-dimethylimidazolidinone, thiodiethanol, dimethylsulfoxide, ethylene glycol monoallyl ether, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, 2-pyrrolidone, sulfolane. ,Ethyl alcohol,
It preferably contains isopropyl alcohol or the like. These water-soluble organic solvents are usually used in the range of 1 to 50% by weight based on the total amount of the recording liquid. On the other hand, water is used in the range of 45 to 95% by weight with respect to the total amount of the recording liquid.

The recording liquid of the present invention contains 0.
1-10 wt% urea, preferably 0.5-5 wt% urea,
By adding a compound selected from thiourea, biuret, and semicarbazide, or by adding 0.001 to 5.0% by weight of a surfactant, the quick-drying property after printing and the printing quality can be further improved. it can.

[0018]

[Example 1]

Diethylene glycol 10 parts by weight, isopropyl alcohol 3 parts by weight, the above-mentioned No. Water was added to 3 parts by weight of dye 1 and the pH was adjusted to 9 with aqueous ammonia to make the total amount 100 parts by weight. The composition was thoroughly mixed and dissolved, filtered under pressure with a Teflon filter having a pore size of 1 μm, and then deaerated with a vacuum pump and an ultrasonic cleaner to prepare a recording liquid.

An ink jet printer (trade name: HG-3000, manufactured by Epson) using the obtained recording liquid
Inkjet recording was performed on the electrophotographic paper (product of Xerox Co., Ltd.) to obtain a high density (1.33) black printed matter. Further, various evaluations were carried out by the following methods (a), (b) and (c). The results are shown in Table-1. (A) Light resistance of recorded image: A xenon fade meter (manufactured by Suga Test Instruments Co., Ltd.) was used to irradiate the recording paper for 100 hours. The discoloration and fading after irradiation was small.

(B) Water resistance of recorded image: Water resistance test (1) Test method After the recorded image was immersed in tap water for 5 minutes, the bleeding of the image was visually examined. The OD value (printing density) of the solid printed portion before and after the immersion was measured with a Macbeth densitometer (TR927). (2) Test results As a result of the above, blurring of the image was slight. The density change of the solid print part before and after the immersion is calculated by the following formula: OD
The residual rate was 98.6%.

[0021]

[Equation 1]         OD residual rate (%) = (OD value after immersion / OD value before immersion) × 100

(C) Storage stability of recording liquid: The recording liquid was sealed in a Teflon container and kept at 5 ° C. and 60 ° C. for 1 hour.
When the change after storage for a month was examined, precipitation of insoluble matter was not observed. In the evaluations of (a), (b), and (c) above, the visual judgment is ◯: good, Δ: somewhat inferior,
X: Evaluated in three stages of failure.

Examples 2 to 4 Nos. Used in Example 1 were used. Instead of the dye of (1), the above No. (6), No. (13) and No.
A recording liquid was prepared by the method of Example 1 except that each of the dyes of (18) was used, and printing was carried out using this to obtain a black recorded product. Furthermore, various evaluations according to (a) to (c) of Example 1 were performed on this recorded material. As a result, good results were obtained in the same manner as in Example 1. The OD residual rates were 99.1%, 97.8%, and 99.8%, respectively. The results are shown in Table 1 below.

Comparative Example 1 No. 1 in Example 1 Instead of the dye of (1), C.I.
I. A composition was prepared using Food Black 2 in the same manner as in Example 1 and then treated to obtain a recording liquid. Using this recording liquid, printing was performed in the same manner as in Example 1 to obtain a black recorded material. For the obtained recorded matter, (a) to (c) of Example 1
Various evaluations were performed. The results are shown in Table 1 below.

[0025]

[Table 1]

Examples 5 to 21 The above-mentioned No. 1 used in Example 1 was used. Instead of the dye of (1), the above No. (2) to (5), No. (7)-(1
2), No. (14) to (17), No. (19) ~
Using each of the dyes of (21), a recording liquid was prepared by the method of Example 1 and printing was carried out to obtain a black recorded matter. Various evaluations according to (a) to (c) of Example 1 were performed on this recorded matter. As a result, as in Example 1, good results were obtained. In addition, dye No. The residual OD of the recording liquid using (2) was 99.5%, and the dye No.
The OD residual rate of the recording liquid using (5) was 97.8%.

[0027]

INDUSTRIAL APPLICABILITY The recording liquid of the present invention is used for ink jet recording, writing instruments, etc., and when recorded on plain paper, a black recorded matter can be obtained, and its printing density, light resistance, and water resistance. In addition to excellent properties, it also has good storage stability as a recording liquid.

[0028]

[0029]

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-58-174459 (JP, A) JP-A-62-39676 (JP, A) JP-A-5-17715 (JP, A) JP-A-6- 220377 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C09D 11/00-11/20 CA (STN) REGISTRY (STN)

Claims (6)

(57) [Claims] 1. A recording liquid comprising an aqueous medium and at least one dye selected from the dyes represented by the following general formula [I] in the form of a free acid. [Chemical 1] [In the formula, R ₁ represents a H, CH ₃ , OCH ₃ group or a group represented by the following general formula [II], and when R ₁ represents a H, CH ₃ or OCH ₃ group, R ₂ represents When H, CH ₃ or OCH ₃ group is represented and R ₁ is a group represented by the general formula [II], R ₂ is H, a substituted or unsubstituted alkyl group having 1 to 9 carbon atoms, or Represents a substituted or unsubstituted alkoxy group having 1 to 9 carbon atoms, R ₃ is H, —SO
Phenyl group which may be substituted with ₃ H group or -COOH group, or carbon number of 1-3 substituted with -COOH group
Represents an alkyl group, R ₄ represents an alkyl group having 1 to 3 carbon atoms which is substituted by H or -COOH group, m represents the number 1 or 2, n represents the number 0 or 1. ) [Chemical 2] ] - (wherein, X is -CO- or -SO ₂ represents, R ₅ represents an alkyl group or an aryl group having 6 to 12 carbon atoms having 1 to 6 carbon atoms.) 2. In the general formula [I], R ₁ represents a group represented by the general formula [II], and R ₂ has 1 to 1 carbon atoms.
The recording liquid according to claim 1, further comprising at least one dye selected from dyes having a structure represented by 9 of substituted or unsubstituted alkoxy groups. 3. In the general formula [I], R ₁ and R
₂ both recording liquid according to claim 1, characterized in that it contains at least one dye selected from the structures represented by -OCH ₃ group dye. 4. A dye for inkjet recording, wherein the free acid form is represented by the following general formula [I]. [Chemical 1] [In the formula, R ₁ represents a H, CH ₃ , OCH ₃ group or a group represented by the following general formula [II], and when R ₁ represents a H, CH ₃ or OCH ₃ group, R ₂ represents When H, CH ₃ or OCH ₃ group is represented and R ₁ is a group represented by the general formula [II], R ₂ is H, a substituted or unsubstituted alkyl group having 1 to 9 carbon atoms, or Represents a substituted or unsubstituted alkoxy group having 1 to 9 carbon atoms, R ₃ is H, —SO
Phenyl group which may be substituted with ₃ H group or -COOH group, or carbon number of 1-3 substituted with -COOH group
Represents an alkyl group, R ₄ represents an alkyl group having 1 to 3 carbon atoms which is substituted by H or -COOH group, m represents the number 1 or 2, n represents the number 0 or 1. ) [Chemical 2] ] - (wherein, X is -CO- or -SO ₂ represents, R ₅ represents an alkyl group or an aryl group having 6 to 12 carbon atoms having 1 to 6 carbon atoms.) 5. In the general formula [I], R ₁ represents a group represented by the general formula [II], and R ₂ has 1 to 1 carbon atoms.
The dye for ink jet recording according to claim 4, which is represented by 9 of substituted or unsubstituted alkoxy groups. 6. In the general formula [I], R ₁ and R
Claim 4 for ink jet recording dye, _wherein the ₂ are both represented by -OCH ₃ group.