JPS63117078A - Water-based ink - Google Patents

Abstract

PURPOSE:To form a water-based ink which gives a recorded image with excellent water resistance and light resistance and also has a good black color tone, by mixing two kinds of specified dyes. CONSTITUTION:This water-based ink contains at least two kinds of dyes, i.e., a dye (A) of formula I and a dye (B) of formula II. In formula I, R1 and R2 are each H, alkyl, alkoxy, hydroxyalkyl, halogen, carboxyl, nitrile, sulfo, carbamoyl, sulfamoyl, acetyl or acetylamino; R3 is H, alkyl or halogen; R4 is H, alkyl, alkoxy, halogen or sulfo; R5 is amino or hydroxyl; X is H, an alkali metal, quaternary ammonium, quaternary phosphonium or a cation of an organic amine; l and m are each 1 or 2. In formula III, R6 and R7 are each H, carboxyl, sulfo, alkyl or alkoxy, X is the same as in formula I. The ratio of A to B is preferably 20/1-2/1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a black aqueous ink suitable for printing, writing, recorders, and inkjet recording.

[Prior art] There have been many inventions related to black water-based ink, for example, Japanese Patent Publication No. 16245/1983 and Japanese Patent Application Laid-Open No. 53-6
No. 1412, No. 54-16243, No. 55-
No. 43153, No. 56-2362, No. 56-
It is disclosed in Japanese Patent No. 11974, Japanese Patent No. 55-144070, etc.

There is a demand for the development of a black ink with much higher density and safety than these conventional black water-based inks, and to meet this demand, attempts have been made to create a black tone by blending dyes of different colors. There is.

Examples of this include JP-A-57-207660 and JP-A-6Q-49069.

However, these water-based inks also have various problems. For example, even if yellow, magenta, and cyan are simply combined, the density of each color is limited, so unless the overall dye density is increased, the image density will be low. If the dye concentration is increased, clogging tends to occur, which is particularly inconvenient when used for inkjet recording. Also, water resistance,
Some of these inks also have poor light resistance, and the reality is that no satisfactory black water-based ink has been obtained.

[Purpose] The present invention provides a water-based ink that provides excellent water resistance and light resistance for recorded images and good black color tone, and in particular does not cause clogging even when used for inkjet recording. This is what we provide.

[Structure] The present invention is an aqueous ink characterized by containing at least two types of dyes: a dye represented by the following general formula (A>) and a dye represented by the general formula (B).

General formula (A): where -, R1, R2: hydrogen, alkyl group, alkoxy group, hydroxyalkyl group, halogen, force! Levoxyl group, nitrile group, sulfonic acid group, Levomoyl group, Lefamoyl group, acetyl group, acetylamino group R3: Hydrogen, alkyl group, halogen R4: Hydrogen, alkyl group, alkoxy group, halogen, sulfonic acid Group R5 Niamino group, hydroxyl group X: hydrogen, alkali metal, quaternary ammonium, quaternary
phosphonium, cationic cross of organic amine, m: 1 or 2 General formula (B): Rr, Ry: hydrogen, carboxyl group, sulfonic acid, alkyl group, alkoxy group X: hydrogen, alkali metal, quaternary ammonium, Fourth
The dye represented by the above general formula (A>) has excellent weather resistance and solubility by itself, but has a problem with black tone.Therefore, we investigated various dyes as complementary color dyes. , general formula (B
) has an ideal black tone by mixing dyes,
It was discovered that a high-density black ink with excellent solubility, water resistance, and light resistance can be obtained, and the present invention was achieved.

The mixing ratio of the dye of general formula (A) and the dye of general formula (B) is 20/1 to 2/1, preferably 571 to 3/1.
A range of is suitable.

Specific examples of the dye represented by the general formula (A>) are listed below.

(A-14) Specific examples of the dye represented by general formula (B) are listed below.

(B-1) (B-2) Dye group: C, 1, direct orange 26 Color tone: Bright reddish orange, Color tone: Bright red, (B-6) (B-7) General formula (A>, ( The total content of the dyes in B) depends on the type of wetting agent, solvent components such as water, characteristics required of the recording liquid, etc., but in general, it is 0.00% of the total amount of the recording liquid.
The content is in the range of 5 to 30% by weight, preferably 1.5 to 6% by weight.

The ink of the present invention uses water as a solvent component, but in order to adjust the physical properties of the ink to desired values, to prevent the ink from drying, to improve the solubility of the dye, etc. It is also possible to use a mixture of a water-soluble organic solvent and water.

Ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, polyhydric alcohols such as glycerin, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol 7-ethyl ester, diethylene glycol monobutyl ether, Alkyl ethers of polyhydric alcohols such as ethylene glycol monomethyl ether and triethylene glycol monoethyl ether;
-pyrrolidone, 1,3-dimethylimidazolidinone, dimethylformamide, triethanolamine, etc.

Among these, particularly preferred are diethylene glycol,
Polyethylene glycol 200-600.

These are triethylene glycol, ethylene glycol, glycerin, and N-methyl-2-pyrrolidone, and by using these, it is possible to obtain high dye solubility and the effect of preventing clogging by preventing water evaporation.

The content of the above-mentioned water-soluble organic solvent in the ink can range from 5 to 80% based on the total weight of the ink, but it is preferably used within the range of 15 to 60% from the viewpoint of viscosity, drying properties, etc.

In addition to the above dyes and solvents, conventionally known additives can be added to the ink of the present invention.

For example, as the preservative and fungicide, sodium dehydroacetate, sodium sorbate, sodium 2-pyridinethiol-1-oxide, sodium benzoate to thulium pentachlorophenol, etc. can be used in the present invention.

Any substance can be used as the D H adjuster as long as it can control the pH of the ink within the range of 9.0 to 11.0 without adversely affecting the ink being prepared.

Examples include amines such as jetanolamine and triethanolamine, lithium hydroxide, sodium hydroxide,
Examples include hydroxides of alkali metal elements such as potassium hydroxide, ammonium hydroxide, quaternary ammonium hydroxides, carbonates of alkali metals such as lithium carbonate, sodium carbonate, and potassium carbonate, and phosphonium hydroxides.

Examples of the chelating reagent include sodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, and sodium uramildiacetate.

Examples of rust preventives include acidic sulfites, sodium thiosulfate, thioglycol ammonium, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.

In addition, water-soluble ultraviolet absorbers, water-soluble infrared absorbers, water-soluble polymer compounds, dye solubilizers, surfactants, etc. can be added depending on the purpose.

All percentages shown below in Examples and Comparative Examples of the present invention are percentages by weight.

Example 1 An ink was prepared by heating the following composition to about 50° C., stirring and dissolving it, and then filtering it through a Teflon filter with a pore size of 0.22 μm.

Dye of specific example (A-1) 2.5% specific example (B-
1> Dye 0.5% diethylene glycol
15,0% N-methyl-2-pyrrolidone 15
．． 0% sodium dehydroacetate 0.2% water
66.8% Inks of Examples 2 to 5 and Comparative Examples 1 to 3 were prepared in the same manner as in Example 1 except that materials having the following compositions were used.

Example 2 Dye of Specific Example (A-3) 2.4% Specific Example (B-
2) Dye 0.6% polyethylene glycol 2
00 15.0% triethylene glycol monomethyl ether 5.0% sodium dehydroacetate 0.2% water
76.8% Example 3 Specific example (A-5> dye 2.8% Specific example (B-
3) Dye 0.2% diethylene glycol
20.0% 1.3-dimethylimidazolidinone 5
．． 0%2.4-dimethyl-6-acetoxy-m-dioxane 0.3% Water 71.7%
Example 4 Specific example (A-7> dye 2.0% Specific example (B-
4> Dye 1.0% diethylene glycol
20.0% glycerin 5.
0%2.4-dimethyl-6-acetoxy-m-dioxane 0.3% Water 71.7%
Example 5 Specific example (A-9> dye 2.5% Specific example (B-
5) Dye 0.5% polyethylene glycol 2
00 15.0% Triethylene glycol monomethyl ether 5.0% Sodium 2-pyridinethiol-1-oxide 0.3% Water 76.7%
Example 6 Specific example (A-11> dye 2.4% Specific example (B
-6> dye 0.8% diethylene glycol
15, O% N-methyl-2-pyrrolidone 1
5.0% Sodium dehydroacetate 0.2% Water 66.8% Example 7 Specific example (A-13> dye 2.3% Specific example (B
-7> dye 0.7% diethylene glycol
20.0% glycerin 5
．． 0%2.4-dimethyl-6-acetoxy-m-dioxane 0.3% Water 71.7%
Comparative Example 1 Specific Example (A-1> Dye 2.5% C, 1, Direct Red 9 1.0% C, L Direct Yellow 142 0.8% Diethylene Glycol
15.0% N-methyl-2-pyrrolidone 15.0
% Sodium dehydroacetate 0.2% Water
66.3% Comparative Example 2 C, 1, Direct Black 32 3.0% Polyethylene Glycol 200 15.0% Triethylene Glycol Monomethyl Ether 5.0% Sodium Dehydroacetate 0.2% Water
76.8% Comparative Example 3 C, 1, Food Black 2 3.0% diethylene glycol 20.0% glycerin
5.0% 2.4-dimethyl-6-acetoxy-m-dioxane 0.3% Water 71.7%
[Effects] The following tests were conducted for Examples 1 to 7 and Comparative Examples 1 to 3.

1) Image color tones An inkjet printer (for Word Processor Report 5600J manufactured by Ricoh) was filled with each ink and printed on commercially available high-quality paper.

The reflection spectrum of the printed image sample was measured using a double beam spectrophotometer (Newly manufactured by Hitachi, Model 228) to examine the color tone.

As a result, the color tone is Vit) 2 + (b”) 2 <
Items with a rating of 3 are marked O in the table.

[a) 11i:, 11 is L) It aMl b) 1 color system (aMllb) chromaticity coordinate] 2) Light resistance of image The image sample obtained in 1) was measured with a fade meter (carbon arc lamp, 63 ℃) for 3 hours, the image density before and after light irradiation was measured using a Macbeth densitometer, and the light resistance (
fading rate) was determined.

Fading rate (%) = [1 - (image density after light irradiation / image density before light irradiation)] x 100 3) Water resistance of image The image sample obtained in 1) was immersed in water at 30 ° C. for 1 minute,
The image density before and after dipping was measured using a Macbeth densitometer, and the water resistance (fading rate %) was determined using the same formula as in section 2).

4) Place the preservative ink in a polyethylene container and store at -20℃ and 4℃.
, 20°C, 50°C, and 70°C for 3 months, and the changes in viscosity, surface tension, and electrical conductivity before and after storage and the presence or absence of precipitation were examined. In the table, samples with no change in physical properties or generation of precipitates were designated as O, no matter what conditions they were stored under.

5) Nozzle clogging test After printing in 1), with the print still stationary, heat at 20°C and 65°C.
%RH for 2 months, and it was examined whether normal printing was possible again after being left.

One ink sample was tested using three printers. In the table, the case where all three printers were able to print normally is shown as O, the case where one or two of the 13 printers were not able to print normally is shown as X, and the case where all three printers were not able to print normally is shown as XX. In addition, if the nozzle of the 5600J printer becomes clogged and jetting is no longer possible, or if the direction of jet jetting changes significantly compared to before it was left unused, this will be automatically detected and the printer will stop operating. equipment is installed.

Table 1 As is clear from the results shown in the table above, the water-based ink of the present invention has excellent water resistance and light resistance of recorded images, and excellent black color tone, and does not cause clogging especially when used for inkjet recording. There is no.

Claims (1)

[Scope of Claims] A water-based ink characterized by containing at least two kinds of dyes: a dye represented by the following general formula (A) and a dye represented by the general formula (B). General formula (A): ▲There are mathematical formulas, chemical formulas, tables, etc.▼ However, R_1, R_2: hydrogen, alkyl group, alkoxy group, hydroxyalkyl group, halogen, carboxyl group, nitrile group, sulfonic acid group, carbomoyl group, sulfamoyl group, acetyl group, acetylamino group R_3: hydrogen, alkyl group, halogen R_4: hydrogen, alkyl group, alkoxy group, halogen,
Sulfonic acid group R_5: amino group, hydroxyl group ▼ R_6, R_7: Hydrogen, carboxyl group, sulfonic acid,
Alkyl group, alkoxy group X: hydrogen, alkali metal, quaternary ammonium, quaternary phosphonium, organic amine cation