JPS61181878A - Oil based ink for ink jet recording - Google Patents

Abstract

PURPOSE:To prevent the recording electrode of a printer from being corroded by oxidation and to improve light resistance of a printed image, by adding an antioxidant to an oil ink for ink jet recording, in which an org. solvent- soluble dye is dissolved in an org. solvent. CONSTITUTION:An org. solvent-soluble dye (e.g. Oil Black or Oil Blue) is dissolved in an org. solvent (e.g. diethylene glycol dimethyl ether). A phenolic antioxidant and pref. triethylenediamine are added thereto to obtain the desired oil ink for ink jet recording. Examples of the phenolic antioxidants are 2,6-di- tert-butyl-4-methylphenol and butylhydroxyanisole. These phenolic antioxidants can be well dissolved in high-boiling solvents conventionally used as the solvents of oil based ink for an ink jet printer, and they do not cause clogging of nozzles.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an oil-based ink for inkjet printers, and particularly to an ink effective for preventing corrosion of recording electrodes.

(Prior art) Among inkjet printers, printers that eject ink to record by creating a potential difference between two electrodes, a recording electrode and a counter electrode, have good ejection response and ejection stability. An ink with an appropriate resistivity value is required to maintain this, and for this reason oil-based inks are used. Most of the recording electrodes in this system are copper electrodes, which are susceptible to corrosion due to oxidation due to long-term contact with ink.

(Problems to be Solved by the Invention) The present invention provides an ink capable of preventing corrosion due to oxidation of recording electrodes of a printer.

(Means for Solving the Problems) The present invention solves the above problems by adding a phenolic antioxidant to the ink.

The phenolic antioxidant used in the present invention includes:
For example, 2,6-ditertiary-butyl-4-methylphenol, 286-ditertiary-butyl-4-ethylphenol, butylhydroxyanisole, 2,2'-methylene-bis-(4-methyl-6-tertiary-butylphenol), 2,2'-methylene-bis-(4-ethyl-6-tert-butylphenol), 4,4'-
Butylidene-bis-(3-methyl-6-tert-butylphenol), 1.3.5-)trimethyl-2,4,
6-tris(3',5'-ditert-butyl-4'
-hydroxybenzyl)benzene, tetrakis-(methylene-3-(3',5'-ditert-butyl-4')
-hydroxyphenyl)propionate)methane, etc., and one or more of these can be added. When triethylenediamine, which is a quencher of singlet oxygen, is used in combination with these antioxidants, the effects of the present invention are further enhanced.

The appropriate amount of antioxidant and triethylenediamine to be added is 0.05 to 3.0% by weight of the ink.
．． 1 to 2.0% by weight is more preferable. If the amount added is less than this, the effect will be low, and if it is too much, it will precipitate in the ink and cause clogging of printer nozzles.

In addition, addition amounts within these ranges do not significantly affect the resistivity value, which is one of the important physical properties of oil-based inks.
The base ink to which the antioxidant is added in the present invention does not need to be special, and many known or actually used oil-based inks for inkjet printers can be used.

In other words, the base ink is an ink prepared by dissolving an oil-soluble dye or other organic solvent-soluble dye with a high boiling point in an organic solvent, and further adding auxiliary agents such as a surface tension regulator and an anti-drying agent as necessary. The ink of the present invention can be prepared by adding the above-mentioned antioxidant and optionally further triethylenediamine to this base ink. The anti-M agent and triethylenediamine may be added during or after the preparation of the base ink.

Example 1 rECS 200J (Petroleum-based high-boiling aromatic solvent manufactured by Exxon Chemical Co., Ltd.) 52 parts Diethylene glycol dimethyl ether 41 parts "Oil black"
HBBJ (manufactured by Orient Chemical Industry Co., Ltd.) 4 parts 2.6-
Ditertiary-butyl-4-methylphenol 3 parts The above components were dissolved with stirring, cooled, and filtered to prepare an ink.

On the other hand, as a comparative example, an ink to which no antioxidant was added was prepared in the same manner.

A copper electrode of a printer was placed in each of the above two types of ink, and a corrosion test was conducted at 60° C. for 30 days.

Although the electrodes in the ink of the present invention were unchanged from before the test,
The electrodes in the ink of the comparative example had progressed to corrosion and turned black.

In addition, a test piece for a light fastness test was prepared by impregnating a filter paper with the ink, and the light fastness test of this test piece was carried out along with Blue Scale using a standard fade meter manufactured by Toyo Rika Kogyo. Sex is level 3 (40
h), but the accelerated lightfastness of the ink of the comparative example was grade 2 (
20h), and the following tests were also conducted in the same manner as the above test method.

Example 2 rECS 100IJ (Petroleum-based high-boiling aromatic solvent manufactured by Exxon Chemical Co., Ltd.) 60 parts 1-methoxynaphthalene 30 parts Rain M (ink drying inhibitor) 4 parts [Izen Spiron Red C-BHJ (Hodogaya) (manufactured by Kagaku Kogyo)
4 parts 2.6-ditertiary-butyl-
4-Ethylphenol 1 part Triethylenediamine 1 part The above components were dissolved with stirring, cooled, and filtered to prepare an ink.

On the other hand, as a comparative example, an ink without the addition of antioxidant and triethylenediamine was prepared in the same manner.

In the recording electrode corrosion test, the electrodes in the ink of the present invention did not change, but the electrodes in the ink of the comparative example were corroded and turned black. On the other hand, in the light resistance test, the ink of the present invention was grade 3 (40h), and the ink of the comparative example was grade 1-2 (20h).
h).

Example 3 Ethylene glycol monoethyl ether 33 parts r
Ecs 200J 59 parts Oleic acid 4 parts [Neozapone Yellow 073'' (manufactured by BASF) 4 parts The above components were dissolved with stirring, cooled, and filtered to obtain a base ink.

Base ink: 99 parts Butylene hydroxyl nisol 0.5
part triethylenediamine 0.5
After stirring and dissolving the above components, the ink of the present invention was prepared by filtering.

In the recording electrode corrosion test, the electrodes in the ink of the present invention did not change, but the electrodes in the base ink were corroded and turned black. In the light fastness test, the ink of the present invention scored 6-7.
grade (100h), and the base ink was grade 6 (100h).

Example 4 Phenethylcumene 75 parts Diethylene glycol monoethyl ether 11 parts Diethylene glycol dimethyl ether 5 parts Oleic acid 5 parts "Oil Blue 615" (manufactured by Orient Kagaku Kogyo Co., Ltd.) 4 parts The above components were dissolved with heating and stirring, cooled, and filtered to obtain the matrix. An ink was prepared.

Base ink 99.7
Part 2.0.3 part of 2'-methylene-bis-(4-methyl-6-tert-butylphenol) The above components were dissolved with stirring and filtered to prepare the ink of the present invention.

In the recording electrode corrosion test, the electrodes in the ink of the present invention did not change, but the electrodes in the base ink turned black. In the light fastness test, the ink of the present invention was grade 5-6 (80 hours)
The base ink was grade 5 (80h).

Example 5 rEC3100IJ 83 parts Diethylene glycol monoethyl ether 7 parts Oleic acid 7 parts Oleosol Fast Blank RLJ (manufactured by Idashi Kagaku Kogyo Co., Ltd.) 3 parts The above components were dissolved with heating and stirring.
After cooling, the mixture was filtered to prepare a base ink.

Base ink 99.6
Part 2.2'-methylene-bis-(4-ethyl-6-tert-butylphenol) 0.2 part Triethylenediamine 0.2 part The above components were dissolved with stirring and filtered to prepare the ink of the present invention.

Also, instead of the above 2,2'-methylene-bis-(4-ethyl-6-tert-butylphenol), 4
・4'-Butylidene-bis-(3-methyl-6-tert-butylphenol), 1,3,5-trimethyl-2,4°6-tris(3',5'-ditertiary-butyl-4'-hydroxy The inks of the present invention were prepared in the same manner except that benzyl)benzene and tetrakis-(methylene-3-(3',5'-ditertiary-butyl-4'-hydroxyphenyl)propionate)methane were used, respectively.

In the recording electrode corrosion test, the electrodes in any of the inks of the present invention did not change, but the electrodes in the base ink were corroded and turned black. In the light fastness test, all inks of the present invention were rated 4th grade, and the base ink was rated 5th grade.

(Effects of the Invention) Addition of the phenolic antioxidant not only prevents corrosion of the recording electrode (but also improves the light resistance of the recorded image).

Phenolic antioxidants dissolve well in high-boiling point solvents commonly used as solvents for oil-based inks for inkjet printers, and do not cause nozzle clogging.

Claims (1)

[Scope of Claims] 1. An oil-based ink for ink-jet recording comprising an organic solvent-soluble dye dissolved in an organic solvent, the oil-based ink for ink-jet recording comprising an antioxidant. 2. An oil-based ink for ink-jet recording comprising an organic solvent-soluble dye dissolved in an organic solvent, the oil-based ink for ink-jet recording comprising an antioxidant and triethylenediamine.