JPS63291967A - Ink composition - Google Patents

Abstract

PURPOSE:To provide an ink composition outstanding in delivery characteristics, free from cloggings, capable of giving printed images which are excellent in clearness and water and light resistances, suitable for ink jet recording use, containing specific water-soluble dye(s). CONSTITUTION:The objective composition containing at least one kind of water- soluble dye of formula I [X is of formula II, III, IV (M' is carboxyl or its salt; A is halogen), etc.; Y is H, of formula V, VI, VII (R is H or alkyl; Z is halogen or H), or -COCH3]. To prepare the dye of the formula I, one of available processes is as follows: (1) a coupler of formula VIII prepared by reaction between H-acid and p-toluenesulfonyl chloride and (2) sodium carbonate are dissolved in water to form a solution; 4,4'-bis-(2-chloranilino) methane and hydrochloric acid are dissolved in water followed by addition of an aqueous solution of sodium nitrite to the resulting solution to form a second solution. Thence, the latter solution is added to the above-mentioned coupler solution.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an aqueous ink composition, particularly an aqueous ink composition suitable for inkjet recording.

[Prior Art] In inkjet recording, in order to perform good recording over a long period of time, it is necessary that the ink used satisfies the following conditions.

1) Ink viscosity, surface tension, specific conductivity, and density must be within appropriate ranges as ink physical properties depending on the droplet generation method and droplet flight direction control method.

2) During long-term storage, long-term use, or recording suspension, precipitation should not occur due to chemical changes, or the physical properties of the ink should not change.

3) The recorded image should have sufficiently high contrast and be clear.

4) The printed image dries quickly.

In order to meet the above requirements, it is required that the molecular extinction coefficient of the dye used in the ink is sufficiently high, and that the solubility of the dye in water and a wetting agent is sufficiently high.

Furthermore, full-color ink used in printers, etc. must: 5) exhibit color tone with excellent purity;

Also, 6) The recorded image must of course be a clear image without smearing, with excellent water resistance, light resistance, and abrasion resistance.

is necessary.

The properties required above are particularly influenced by the dyes among the materials used in the ink, and the development of new dyes has been awaited to satisfy these requirements.

[Objective] The object of the present invention is to obtain an aqueous ink that satisfies all of the above-mentioned requirements for an ink.

[Structure] The present invention is a water-based ink characterized by containing at least one kind of water-soluble dye represented by the following general formula.

General formula % Formula % M is a sulfonic acid group or its salt; (M' is a carboxyl group or its salt; △ is a halogen; R is hydrogen or an alkyl group; Z is a halogen or a hydroxyl group) sulfonic acid or carboxylic acid in the above formula Examples of cations that form salts include li'', Na'', and K''.
, quaternary ammonium are preferred.

The water-soluble dye is preferably used in an amount of 1 to 10% by weight of the total ink component.

Preferred specific examples of dyes used in the aqueous ink composition of the present invention and their absorption spectrum maximum wavelengths (nm) are listed below.
1. Shown in Table-2.

The absorption spectrum was measured using an aqueous solution of Na2cOx1.06q/m and NaHCO30,33g/m2.

Table-1 Dye Number Table-2 Absorption Spectrum Maximum Wavelength (In) The synthesis method is described below.

For example, in the case of 3d2 (dye No. 10>).

2 g of the following coupler (k3) obtained by reacting para-toluenesulfonyl chloride with H acid and 1.8 g of sodium carbonate are dissolved in 50 cc of water and kept at 5°C or below.

Separately 4,4゛-bis-(2chloroanilino)methane 0,
Dissolve 52 (11 and 1.0 liter of 35% hydrochloric acid in 50 cc of water, add tOcc of water containing 0.260 sodium nitrite at 5°C or below, and remove excess sodium nitrite with sulfamic acid. Prepare the solution.

Toshisha's solution is added to the coupler solution at 5 DEG C. or lower, and the desired dye is prepared while keeping the pH at 8 to 10 with sodium carbonate, after which the inorganic salt is removed by a conventional method.

The same applies to other dyes. d+, d2, and d4 are each the above-mentioned 4.4゛-bis-(2-chloroanilino)
Metaphenylenediamine (dl) instead of methane, 3
, 5-diaminobenzoic acid (d ] ) , ]5.5'-
Methylene anthranilic acid (d4) is used.

The aqueous ink of the present invention is prepared by mixing the following aqueous organic solvent with water for purposes such as adjusting the ink physical properties to desired values, preventing ink drying, and improving dye solubility. It can also be used as

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 7-methyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene Alkyl ethers of polyhydric alcohols such as glycol monomethyl ether and triethylene glycol monomethyl ether, other N-methyl-2-pyrrolidone,
2-pyrrolidone, 1,3-dimethylimidazolidinone,
Dimethylformamide, triethanolamine, etc.

Among these, particularly preferred are diethylene glycol,
Polyethylene glycols 200 to 6001 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 moisture evaporation.

The content of the above-mentioned water-soluble organic solvent in the ink can be used in the range of 5 to &theta.% based on the total weight of the ink, but it is preferably used in the range of 10 to 40% 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, sodium pentachlorophenol, etc. can be used in the present invention.

Any substance can be used as the pH 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.

Specific electrical conductivity regulators include, for example, potassium chloride,
These include inorganic salts such as ammonium chloride, sodium sulfate, and sodium carbonate, and water-soluble amines such as triethanolamine.

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, ammonium thioglycolate, 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.

Examples of the present invention are described below.

Table 3: Humectants> A, glycerin B, diethylene glycol C, triethylene glycol D, N-methyl-2-pyrrolidone, preservative and fungicide> A, sodium dehydroacetate B, sodium sorbate C0, sodium benzoate, comparative dye> NO, I C, 1, Acid Violet 7No,
2 0.1. Acid Violet 49N0.3
C, 1, Direct Red 9 Examples 1 to 9, Comparative Example 1
The following tests were conducted for 3 to 3, and the results are shown in Table 4.

1) Image clarity An inkjet printer for Word Processor Report 5600J manufactured by Ricoh was filled with the prepared ink and printing was performed.

Q in Table 1 regarding the inks that produced clear images.
Represented by a mark.

2) Light resistance of the image The image sample obtained in 1) was exposed to a fade meter (carbon arc lamp, 63°C) for 3 hours, and the image density before and after light irradiation was measured using a Macbeth densitometer, and the light resistance was calculated using the following formula. (
fading rate) was determined.

Fading rate (%) - [1 - (Image density after light irradiation / Image density before light irradiation) ko The image density of one flame before immersion was measured with a Macbeth densitometer, and (
The water 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 were examined, as well as the presence or absence of precipitate precipitation. In Table 1, 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 The bond printed in 1) was heated to 65% at 20°C with the printed body still.
The paper was left in an RH environment for two months, and it was examined whether normal printing was possible again after being left in the environment.

Table 4 [Effects] As is clear from the above explanation, the aqueous ink composition of the present invention has excellent jetting characteristics, is free from clogging, and
Images obtained using this water-based ink exhibit remarkable effects such as excellent clarity, water resistance, and light resistance.

Claims (1)

[Claims] The following general formula ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [In the formula, There are chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, Y is H, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ Mathematical formulas, chemical formulas ,
There are tables, etc. ▼, -COCH_3, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ M is a sulfonic acid group or its salt; (M' is a carboxyl group or its salt; A is halogen; R is hydrogen or an alkyl group; Z is a halogen or a hydroxyl group)] An aqueous ink composition containing at least one water-soluble dye represented by the following.