JPS612772A - Ink composition - Google Patents

Abstract

PURPOSE:The titled composition that contains, as major components, dyes with a specific structure, a humectant and water, thus being capable of forming excellent image of blue color in ink-jet recording without nozzle clogging even in intermittent use for a long period of time. CONSTITUTION:The objective composition is obtained by using (A) a dye of formula I [CuPc represents copper phthalocyanine; M is H, alkali metal; R1, R2 are H, lower alkyl; R3 is CH2-(CH2)p-, formula II (p, q are 1-4); l, m are 0-3; n is 1-4 wherein l+m+n are 2, 3, 4; one of X and Y is residue of (alkoxy)alkylamine of 6-18 carbon atoms and the other is residue of (alkoxy)alkylamine of 1-18 carbon atoms], (B) a humectant, preferably ethylene glycol and (C) water. The component A is obtained by sulfonating copper phthalocyanine, allowing the product to react with an alkali metal, allowing the resultant intermediate to react with an equimolar amount of cyanuric halide by condensation, followed by reaction of the product with amines corresponding to X and Y in order.

Description

Detailed Description of the Invention (I) Industrial Application Field The present invention relates to an aqueous ink composition suitable for printing, writing instruments, recorders, stamps, etc., and particularly for long-term intermittent use in inkjet recording. The present invention also relates to an aqueous ink composition for inkjet recording that can form excellent blue images without causing nozzle clogging or the like.

(2) Prior art Usually, aqueous ink compositions are basically composed of a dye, a polyhydric alcohol or its ethers called a wetting agent, and water, and in particular, it is possible to use this ink composition. In order to perform accurate inkjet recording, various conditions are required for the ink used.

First, the ink physical properties depending on the droplet generation method and droplet flying direction control method are as follows: ink viscosity, surface tension, specific conductivity,
It is necessary that the density is within an appropriate range. and,
Precipitates should not be generated due to chemical changes during long-term storage, long-term use, or recording suspension, and the physical properties of the ink should not change. The ejection nozzle of a recording device generally has a diameter of about 10 to 60 μm, and if the nozzle is clogged with deposits, droplets cannot be ejected. Even if the nozzle is not completely clogged, if solid matter or sticky matter adheres to the vicinity of the nozzle, or if the physical properties of the ink that were adjusted to desired values during ink formulation change, recording performance, ejection stability, and ejection response may deteriorate. descend.

The recorded image has sufficiently high contrast,
Of course, it is also required to be clear and have water resistance, light resistance, and abrasion resistance.

Conventionally, as blue dyes for water-based inks, direct dyes and acid dyes that are water-soluble and have excellent water resistance and light resistance have been used. For example, blue dyes include C,1,
Direct Blue 1.8.71.76.78,108,
163, 195, 202, 236. C, 1, Acid Blue 1.7.126.175.234, etc.

However, since conventional direct dyes have poor solubility, it is not possible to sufficiently increase image density and contrast, and the dyes tend to coagulate and precipitate during storage or use, causing nozzle clogging. In order to improve this drawback, various organic amines and surfactants are added as dye dissolving agents, but these additives can cause corrosion of the various components that make up the recording device or cause the ink liquid to foam. If the nozzle is clogged, the image may become unclear. Furthermore, when conventional acid dyes are used, the color tone is clear, but the water resistance is particularly poor, and special paper must be used.

For this reason, water-based inks, especially inkjet recording inks, have excellent solubility, exhibit good storage stability and nozzle clogging, and form images with excellent water resistance and light resistance. There is a strong need for dyes that can

(3) Problems to be Solved by the Invention While conducting research to improve the drawbacks of conventional water-based inks, particularly inkjet recording inks, as described above, the inventors have investigated in depth the causes of nozzle clogging. death,
While ink is ejected intermittently for a long period of time, slight changes in the ink composition adhering to the vicinity of the nozzle tip, especially the water content ratio, may occur, resulting in agglomeration and precipitation of water-soluble dyes and low-vehicle solubility. I learned that this caused the nozzle to clog. This was accomplished based on the knowledge that the present invention provides.

That is, an object of the present invention is to provide a composition that satisfies all of the required characteristics of aqueous inks, particularly inkjet recording inks. It is an object of the present invention to provide an improved dye for an aqueous ink composition that does not cause clogging, particularly during storage or use of the ink. Another object of the present invention is to provide a dye that can be easily obtained in high purity and is suitable for use in water-based inks.

(4) Means for Solving the Problems A means for achieving the object of the present invention is to use a dye with a special structure that has a higher affinity for wetting agents than for water. Its structure is as follows.

The present invention is an ink composition containing a dye, a wetting agent, and water as main components, and is characterized by containing a dye represented by the following general formula (I).

■ (In the formula, CuPc represents copper phthalocyanine.

M represents hydrogen, an alkali metal, ammonia or an organic amine. R1 and R2 represent hydrogen, a lower alkyl group or a hydroxyalkyl group, and R3 is -C)12(C)l
jP, -CH3CN, (NHCH2C)I, keq(p
and q represents 1 to 4]. l and parent are respectively 0, l,
2 or 3, n is 1.2.3, or 4, l+
The sum of m+n is 2.3 or 4. One of X and Y is a C6-1B alkylamine residue or an alkoxyalkylamine residue, and the other is a C2-I8 alkylamine residue, alkoxyalkylamine residue, alkanolamine residue, or arylamine residue. basis)
In the dye represented by the general formula (I) used in the present invention, specific examples of amines represented by NR and R2 include N
Hλ, ethylamine, dimethylamine.

methylethylamine, propylamine, butylamine,
dibutylamine, octylamine, ethanolamine,
Examples include butanolamine, jetanolamine, octatoolamine, and the like. Further, specific examples of polyamines represented by NHR3NH include ethylenediamine,
These include propylene diamine, butylene diamine, diethylene triamine, triethylene tetramine, and tetraethylene pentamine.

06 to +g corresponding to the residue represented by X or Y in the dye represented by the general formula (T) used in the present invention
Specific examples of the alkylamine and alkoxyalkylamine include hexylamine, 2-ethylbutylamine, diisopropylamine, heptylamine, octylamine, N,N-dibutylamine, N-ethyl-N-hexylamine, -Ethylhexylamine, nonylamine, cyamylamine, dodecylamine, dioctylamine, cetylamine, stearylamine, methoxyhexylamine, propoxybutylamine, butoxyhexylamine, hexyloxyethylamine, 2
-ethylhexyloxypropylamine and the like. Examples of the lower alkylamine and alkoxyalkylamine having C6 or less include methylamine, ethylamine, propylamine, butylamine, amylamine, dimethylamine, diethylamine, methylethylamine,
Examples include methoxyethylamine, ethoxyethylamine, propoxyethylamine and the like. Examples of alkanolamines include ethanolamine, jetanolamine, propatoolamine, butanolamine, heptatoolamine, and octatoolamine.

Examples of arylamine include aniline and aniline sulfonic acid.

These include toluidine and benzylamine.

The organic amine of M may be the above-mentioned C(-1?alkylamine or alkoxyalkylamine), or other amines such as CI, s alkylamine or alkoxyalkylamine, alkanolamine, aniline , benzylamine, cycloalkylamine, etc.

If the alkylamine or alkoxyalkylamine residue represented by X or Y in the above general formula (I) is 06 or less, the dye itself cannot be purified easily, the dye has strong water solubility, and has poor wetting agent affinity. As a result, the nozzles become clogged during long-term use, resulting in poor water resistance of images. C11 again? If the dye exceeds this value, the affinity of the dye for both water and wetting agent is poor, a large amount of solvent is required, and even then, the image density cannot be increased.

Unsuitable under all conditions including storage stability and nozzle clogging.

The dye of the general formula CI) used in the present invention is, for example, 1 mol of an intermediate dye obtained by sulfonating or chlorosulfonating a required amount of copper phthalocyanine in a conventional manner and reacting it with an alkali metal, amine or alkylene polyamine; It can be easily obtained by condensing 1 mol of cyanuric halide using a conventional method, and then reacting an amine corresponding to X and then an amine corresponding to Y using a conventional method.

Since these dyes have essentially poor water solubility, they can be easily separated from impurities such as inorganic salts produced as by-products during synthesis, making it easy to obtain high-purity products.

Examples of the dye represented by the general formula (I) include those shown in Table 1.

As the wetting agent used in the present invention, those conventionally used for water-based inks can be used, but thermally stable ones are particularly preferably used.

For example, polyhydric alcohols, cellosolves, calpitols, etc., specifically, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, glycerin.

polyethylene glycol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether,
Diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether.

Examples include triethylene glycol monomethyl ether and triethylene glycol monoethyl ether. In addition to these, dimethylformamide, pyrrolidone, alcohol, alkanolamine, etc., which are commonly used as dye dissolving agents, can also be used.

The aqueous ink composition of the present invention contains a dye, a wetting agent, and water. The amount of the dye represented by general formula (I) to be added is usually 0.5 to 100 parts by weight of the ink composition.
The content is 20 parts by weight, preferably 1 to 15 parts by weight.

If it is less than 0.5 parts by weight, the color will be pale, and if it exceeds 20 parts by weight, precipitation may occur over a long period of time.

Furthermore, the dye represented by the general formula (I) usually has a blue color and can be used alone or in combination, and conventionally used dyes for water-based inks can also be used in combination as long as the characteristics of these dyes are not impaired. can. The wetting agent is added to the recording medium liquid (vehicle) in a necessary amount as desired so as to satisfy the desired characteristics, and the amount added is usually 1 to 80 parts by weight per 100 parts by weight of the ink composition. It is preferable to include parts by weight. These wetting agents may be used alone or in combination of two or more types provided that they do not adversely affect each other.

In the present invention, various conventionally used additives are used to provide more remarkable properties.

For example, antiseptic and antifungal agents such as sodium dehydroacetate, 2,2-dimethyl-6-acetoxydioxane, ammonium thioglycolate, etc.; antirust agents such as acid sulfite,
These include sodium thiosulfate, dicyclohexyl ammonium nitrite, and other ultraviolet absorbers, viscosity modifiers, surface tension modifiers, pH modifiers, resistivity modifiers, infrared absorbers, and the like.

(5) Functions and Effects The dye represented by the general formula (T) used in the aqueous ink composition of the present invention differs from the physical properties of dyes used in conventional aqueous ink compositions, and one characteristic is that it is poorly water-soluble. At the same time, another feature is that it has improved affinity for polyhydric alcohols, cellosolve, and calpitol.

By selecting a powerful configuration, it is possible to sufficiently handle a wide range of compositions, and it has become possible to always maintain an extremely stable solution state even with slight changes in the ink composition during storage or use. This, combined with the fact that it is easier to separate inorganic by-products during dye synthesis than with conventional dyes, making it possible to obtain highly pure dyes, makes it possible to produce images with high density and clarity. Now you can.

(6) Examples The present invention will be described below with reference to Examples, but the present invention is not limited to these Examples.

Examples 1 to 12, Comparative Examples 1 to 3 The components of each formulation shown in Table 2 were thoroughly mixed, thoroughly stirred at 50°C, and filtered under pressure using a 05μ membrane filter to prepare a recording liquid.

The storage stability, jetting stability, and image sharpness of each recording liquid were tested in the following manner, and the results are shown in Table 2.

1) Storage stability Seal the ink in a Pyrex test tube and store at 0°C.

After each sample was left at 50°C for one month, the presence or absence of precipitates was examined. The amount of precipitation was expressed as follows.

◎ No precipitates at all o Almost no precipitates Δ n A small amount X I+ A large amount 2) Ejection stability The ink was placed in an ink tank of an inkjet device having a nozzle with a hole diameter of 30μ, and a cycle of ejecting for 1 second at 1 second intervals was performed. After running for 24 hours, it stopped for 10 days, 20 days,
After being left at room temperature for 30 days, 60 days and 90 days,
I sprayed again and checked to see if the nozzle was clogged. The maximum number of days it can be left unused for re-injection without clogging is displayed.

3) Image clarity Images were jet-recorded on high-quality paper using the inkjet device described in 2), and the clarity was visually determined.

◎ Excellent. O Normal. Δ Insufficient. X Inferior.

As is clear from the results in Table 2, the aqueous ink composition of the present invention has better blue image quality than inks using conventional dyes, can be stored for a long period of time, and has improved nozzle clogging. I know that there is.

Claims (1)

[Scope of Claims] An ink composition containing a dye, a wetting agent, and water as main components, characterized by containing a dye represented by the following general formula (I). General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, CuPc represents copper phthalocyanine. M represents hydrogen, alkali metal, ammonia, or organic amine. R_1 and R_2 are hydrogen, lower It represents an alkyl group or a hydroxyalkyl group, and R_3 is CH_2-(CH_2
)-_p, -CH_2CH_2-(NHCH_2CH_
2) −_q [p and q are 1 to 4]. l and m each represent 0, 1, 2 or 3, n represents 1, 2, 3 or 4, and the sum of l+m+n is 2, 3 or 4. One of X and Y is an alkylamine residue or an alkoxyalkylamine residue of C_6_ to_1_8, and the other is an alkylamine residue of C_1_ to_1_8, an alkoxyalkylamine residue, an alkanolamine residue, or an arylamine residue. It is the basis. )