JPH0216171A - Water-base ink - Google Patents

Abstract

PURPOSE:To obtain a water-base ink for ink jet recording which gives a printed image with excellent definition, water resistance, and light resistance, and hardly causes clogging by incorporating a water-soluble dye containing a quaternary ammonium or phosphonium as a counter ion. CONSTITUTION:This water-base ink contains at least one water-soluble dye of formula I wherein the counter ion X comprises a quaternary ammonium or phosphonium of formula II. In formulas I and II, R1 is alkyl, phenyl, hydroxyl or alkoky; R2 is H or alkyl; R3 is a sulfo, alkyl, optionally substituted aryloxy, alkoxy, hydroxyalkyl or halogen; R4 is alkyl, alkoxy or halogen; l is 0 or 1; m is 0 to 3; M is N or P; and R5 to R8 are each 1-4C alkyl, hydroxyalkyl or haloalkyl.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an aqueous ink suitable for inkjet recording, and can also be used as an aqueous ink for recorders, pen blocks, writing instruments, etc.

C. Prior Art] Many inventions related to magenta and red water-based inks have been made in the past. For example, Japanese Patent Publication No. 57-35728, Japanese Patent Publication No. 57-35729, etc. using xanthine dyes,
JP-A-58-101171 using a monoazo dye. JP-A-58-174457 etc. using azothiazole dyes, JP-A-58-176275 using azothiazole dyes, JP-A-57-19719 using anthrapyridone dyes, JP-A-59-7
4173 etc. are disclosed.

However, at present, it is not possible to obtain satisfactory magenta and red water-based inks that have a clear color tone, excellent water resistance and light resistance, and excellent storage stability. Particularly when used as an aqueous inkjet ink, there are problems such as changes in the ejection direction and clogging, and the ink cannot be used unless it has sufficient solubility in a polyhydric alcohol or the like as a solvent. Furthermore, when used in an on-demand inkjet printer that uses thermal energy to eject ink through bubbles, it is important to obtain dye dissolution stability in order to maintain its reliability.

[Problems to be Solved by the Invention] The present invention aims to provide magenta and red water-based inks for inkjet recording that solve the conventional drawbacks, and more specifically, improve image clarity and water resistance. sex,
The object of the present invention is to provide magenta and red aqueous inks for inkjet recording that have excellent light resistance, particularly excellent stability in the jetting direction, and are resistant to clogging.

[Means for Solving the Problems] The present invention contains at least one water-soluble dye shown in the following formula, and as a counter ion X of the dye, -
The present invention relates to an aqueous ink characterized by containing quaternary ammonium or quaternary phosphonium represented by (B).

- Clothes allowance (A) However, RI = alkyl group, phenyl group, hydroxyl group, alkoxy group R2: hydrogen, alkyl group, R3 = sulfonic acid group, alkyl group, optionally substituted aryloxy group, alkoxy group, hydroxyalkyl group, /10gen R4=alkyl group, alkoxyi,! %
Logen l: 0 or 1 m: 0-3 General formula (B) M: Nitrogen or phosphorus R5-R: Alkyl group having 1 to 4 carbon atoms, hydroxyalkyl group, and As a result of intensive studies to improve the drawbacks of magenta dyes, it was found that the dye of -Fukudai (A) contains quaternary ammonium or quaternary phosphonium shown by -Fukudai (B) as a counter ion. It was possible to obtain a water-based inkjet ink that has excellent solubility, is resistant to clogging, and has excellent stability in the jetting direction.

- It was revealed in Japanese Patent Application Laid-Open No. 57-197 that the dye with the skeleton structure shown by Clothing Cost (A) is suitable as an inkjet dye.
191, JP-A-59-7413, etc.,
In the present invention, we have discovered that it is possible to dramatically prevent clogging during long-term storage and prevent dye precipitation when subjected to thermal changes without impairing the light resistance and water resistance.

This converts the counter ion into the fourth compound represented by the general formula (B).
It is thought that this is done to improve solubility in polyhydric alcohols by changing to quaternary ammonium or quaternary phosphonium.

The counter ion of the dye of general formula (A) is replaced by the counter ion of the dye of general formula (I3
) can be easily obtained by using the hydroxide of (B). It can also be made into powder by reprecipitation by adding acetone or the like or by evaporation of the solvent.

Specific examples of general formula (A) of the present invention are shown below.

The above dyes are F P 104 [185B and US P 2
644821 etc., and can be obtained in the free acid form. However, it can be easily synthesized in the free acid form by a known method such as that shown in Acid Red 143 (Na salt of the dye of Example A5) etc., which is commercially available in the sodium form. It is also possible to form it into an acid form.

However, it is difficult to completely change the Na type to the free acid type, and Na ions may remain. Further, by using a hydroxide of quaternary ammonium or quaternary phosphonium of general formula (B) from the synthesis stage, it is also possible to produce the aqueous ink of the present invention without obtaining a free acid.

In the present invention, all the sulfonic acids in the dye are (B)
It does not need to be a grade ammonium or a quaternary phosphonium, and it is sufficient that it is substituted at least 30% or more, more preferably 50% or more.

As other counter ions, Na and Li salts are preferred, and K and NH4 salts are not preferred.

Also, polyvalent metals such as Ca" and AI".

The presence of Mn'+ etc. reduces the solubility of the dye, and it is not preferable for these ions to be contained.

Specific examples of the quaternary ammonium and quaternary phosphonium hydroxides of general formula (B) are shown below.

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.

Polyhydric alcohols such as triethylene glycol, polyethylene glycol, polypropylene glycol, glycerin, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene Alkyl ethers of polyhydric alcohols such as glycol monoethyl ether, and others such as N-methyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethylimidazolidinone, dimethylformamide, and triethanolamine.

Among these, particularly preferred are diethylene glycol,
These are polyethylene glycol 200-600, 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 range from 5 to 8,096% based on the total weight of the ink, but it is preferably used in 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 a preservative and fungicide, sodium dehydroacetate,
Sodium sorbate, sodium 2-pyridinethiol-1-oxide, sodium benzoate, sodium pentachlorophenol, and the like can be used in the present invention.

Any substance can be used as the P1121 regulator as long as it can control the Pl+ of the ink without affecting the form of the ink to be formulated.

Examples include amines such as jetanolamine, triethanolamine, and lithium hydroxide.

Hydroxides of alkali metal elements such as sodium hydroxide and potassium hydroxide, ammonium hydroxide, quaternary ammonium hydroxide, quaternary phosphonium hydroxide, and alkali metals such as lithium carbonate, sodium carbonate, and potassium carbonate. carbonates, etc.

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, and ammonium thioglycolate.

Examples include diisopropylammonium nitrite, pentaerythritol tetranitrate, dicyclohexylammonium nitrite, and dryide.

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 and comparative examples of the present invention are shown below. All percentages are by weight.

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

Dye of specific example (A-1) 2.0% diethylene glycol 1000% glycerin
5.0% diethylene glycol monobutyl ether 5.0% specific example (B
25% aqueous solution of -1) 2.0% sodium dehydroacetate 0.2% ion-exchanged water
Remaining Amount 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-2) 265% polyethylene glycol 200 10.0% N-methyl-2
-Pyrrolidone 1000% Specific example (B-2) 25
% aqueous solution 2.0% 2.4-dimethyl-6-acetoxy-1-dioxane 0.2% ion-exchanged water Remaining amount Example 3 Dye of specific example (A-4) 3.0% triethylene glycol 15.0 %1.3-dimethylimidazolidinone 10.0%Specific example (B-7)-2
5% aqueous solution 2.5% 2.4-dimethyl-〇-acetoxyrhodioxane 062% ion-exchanged water Remaining amount Example 4 Dye tetraethylene glycol diethylene glycol monobutyl ether specific example (B-10) of specific example (A-7) ) 25% aqueous solution of 2-pyridinethiol-1-oxide sodium ion-exchanged water Example 5 25% aqueous solution of dye ethylene glycol glycerin of specific example (A-9) (B-12) 2.4-dimethyl-〇 - Acetoxy-m-dioxane ion-exchanged water comparative example 1 Dye diethylene glycol of specific example (A-1) 2.5% 20.0% 5.0% 2.0% 0.3% Remaining amount 2.0% 12. 0% 5.0% 2.0% 0.2% Remaining amount 2.0% 1000% Glycerin diethylene glycol monobutyl ether Potassium hydroxide Dehydroacetate Sodium Ion exchange water Comparative example 2 C01, Acid Red 92 Polyethylene glycol 20O N-Methyl- 2-pyrrolidone sodium hydroxide 2.4-dimethyl-〇-acetoxy-rhodioxane ion-exchanged water Comparative Example 3 c, 1. Direct Red 81 25% aqueous solution of triethylene glycol 1.3-dimethylimidazolidinone specific example (B-7) 2.4-dimethyl-〇- 5.0% 5.0% 0.3% 0.2% Remaining Amount 2.0% 1000% 1000% 0.2% 0.2% Remaining amount 3.0% 15.0% 1000% 0.2% Acetoxy-l-dioxane ion exchange water comparative example 4 C, 1, Direct Red 227 Tetraethylene glycol diethylene glycol monobutyl ether sodium hydroxide 2-pyridinethiol-! Sodium oxide ion exchange water comparative example 5 C91, Acid Red 254 25% aqueous solution of glycerin diethylene glycol diethylene glycol monobutyl ether specific example (B-12) Sodium dehydroacetate ion exchange water 0.2% Remaining amount 2.0% 20.0% 5 .0% 0.1% 0.3% Remaining amount 2.5% 5.0% 10.0% 5.0% 0.1% 0.2% Remaining amount test results examples (1) to (5) The following tests were conducted on Comparative Examples (1) to (4).

1) Image clarity Ricoh Word Processor Report 5600 J
The prepared ink was filled into an inkjet printer for printing.

In Table 1, regarding the inks that produced clear images, O
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. (
The fading rate) was determined.

3) Water resistance of the image The image sample obtained in (■) was immersed in water at 30°C for 1 minute,
The image density before and after immersion was measured using a Macbeth densitometer (2
) The water resistance (fading rate: 96) was determined using the same formula as the formula in section ).

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 changes in viscosity, surface tension, electrical conductivity, and presence or absence of precipitate were examined before and after storage. 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) After printing in the nozzle clogging test
%1ull environment for two months, and it was examined whether normal printing was possible again after being left. One ink sample was tested using three printers.

In Table 1, Q indicates that all three printers could print normally, × indicates that one or two of the three printers could not print normally, and XX indicates that all three printers could not print normally. Indicated. The 5600J printer has a device that automatically detects this and stops the printer if the nozzle becomes clogged and jetting is no longer possible, or if the direction of jet jetting changes significantly compared to before it was left unused. installed.

Table 1: The magenta color tone is good, and there is no clogging even when used for inkjet recording.

Claims (1)

[Scope of Claims] Contains at least one water-soluble dye represented by the following general formula (A), and as a counter ion X of the dye, quaternary ammonium or quaternary phosphonium represented by the general formula (B). Water-based ink general formula (A) characterized by containing ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ However, R_1: alkyl group, phenyl group, hydroxyl group, alkoxy group R_2: hydrogen, alkyl group, R_3: sulfonic acid group , alkyl group, optionally substituted aryloxy group, alkoxy group, hydroxyalkyl group, halogen R_4: alkyl group, alkoxy group, halogen l: 0 or 1 m: 0-3 General formula (B) ▲ Numerical formula, chemical formula, There are tables, etc. ▼ However, M: Nitrogen or phosphorus R_5 to R_8: Alkyl group having 1 to 4 carbon atoms, hydroxyalkyl group, and halogenated alkyl group