JPH06336567A - Ethanol-based ink for marking pen - Google Patents

Abstract

PURPOSE:To obtain an ink free from the deposition of the dye and excellent in long-term stability and water resistance by mixing a dye having a specified structure, an ethanol-soluble resin and ethanol. CONSTITUTION:This ink contains a dye of the formula (wherein R<1> and R<2> are each 1-4C alkyl; and (n) is 1 to 5), an ethanol-soluble resin and ethanol. The amount of the dye to be incorporated is 1-20wt.% based on the total ink considering, e.g. the viscosity of ink. Other ethanol-soluble dye may be used in an amount undetrimental to the object. Ethanol, preferably having at least 99% undenaturated, is used in an amount of 65-98wt.% based on the total ink. As the ethanol-soluble resin, an ethanol-soluble alkylphenol resin or ketone resin is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink used for a marking pen, and more particularly to an ink for a marking pen using ethanol as a main solvent.

[0002]

2. Description of the Related Art Solvents such as xylene and methyl cellosolve, which have good solubility in oil-soluble dyes, have been used in inks for oil-based marking pens, but these solvents have problems in human safety such as odor and toxicity. Therefore, there is a possibility that restrictions or limitations will be required on the usage method and usage environment. As a solution to these problems, an alcohol-based ink mainly composed of an alcohol-based solvent having low odor and low toxicity, particularly an ink used for a marking pen containing ethanol as a main solvent (hereinafter referred to as an ethanol-based ink)
Has been developed in recent years. However, these ethanol-based inks have a relatively poor solubility of ethanol in organic solvents such as dyes and resins, and the oil-soluble dyes that have been used in conventional oil-based marking pens have functional groups that interact with ethanol. There is a problem that the dye is insoluble because it is small, or even if it dissolves it has poor stability over time such as precipitation of the dye after a long period of time, good compatibility with ethanol, and ethanol soluble in ink Dyes having good compatibility with resins are desired. In particular, black ink, which is used in a large amount, is desired.

[0003]

DISCLOSURE OF THE INVENTION The present invention is to solve the above-mentioned drawbacks in a marking pen ink containing ethanol as a main solvent, and is a marking pen which is free from dye deposition and is excellent in stability over time and water resistance. The present invention aims to provide an ethanol-based ink for use, especially a black ink.

[0004]

As a result of intensive studies to solve the above-mentioned problems, the present inventors succeeded in finding a dye having a specific structure that is compatible with ethanol and an ethanol-soluble resin. The present inventors have completed the ethanolic ink for marking pens of the present invention. That is,

The ethanolic ink for marking pens of the present invention has the general formula

[0006]

[Chemical 2] (Here, R ¹ and R ² are alkyl groups having 1 to 4 carbon atoms, and n is an integer of 1 to 5)

It is characterized by containing a dye represented by the formula (1), an ethanol-soluble resin and ethanol. A black ink using only the dye as a dye is preferable.

Specific examples of the dye used in the ink of the present invention include compounds represented by the following formulas (2) to (4).

[0009]

[Chemical 3]

[0010]

[Chemical 4]

[0011]

[Chemical 5]

The blending amount is not particularly limited, but it is used in the range of 1 to 20% by weight of the total amount of the ink in consideration of ink viscosity and the like. Further, other ethanol-soluble dyes may be used to the extent that they do not impair the purpose.

The ethanol used in the ink of the present invention is used as a main solvent. This ethanol is not particularly limited, but preferably 99% or more unmodified ethanol is used. With respect to the blending amount, 65 to 98% by weight of the whole ink is used. As a solvent other than ethanol, another solvent may be added as an auxiliary solvent such as a whitening agent, but the amount of ethanol in all the solvents is 90% by weight.
The above content is preferably 95% by weight or more.

As the ethanol-soluble resin used in the ink of the present invention, an ethanol-soluble alkylphenol resin or an ethanol-soluble ketone resin is used. Specific examples of the ethanol-soluble alkylphenol resin include:
Examples include Hitanol 2501 (manufactured by Hitachi Chemical Co., Ltd.), Tamanor PA (manufactured by Arakawa Chemical Industry Co., Ltd.) and the like. Further, specific examples of the ethanol-soluble ketone resin include ketone resin K90 (manufactured by Arakawa Chemical Industry Co., Ltd.) and Hirac 110H (manufactured by Hitachi Chemical Co., Ltd.). The addition amount of these resins is not particularly limited,
The amount may be an amount suitable for the required fixing force and the drying resistance of the pen core, and preferably 1 to 15% by weight of the total ink composition in consideration of the ink viscosity.

The ink of the present invention is excellent in stability over time and water resistance, and is particularly suitable for use in black ink. The reason is that the dye used has a structure in which it is salted with a metal complex dye and a quaternary ammonium having a long-chain alkylene as shown in the general formula (1). It is considered that the aging stability is excellent due to the high value. Alternatively, since the dye is a special salt-forming dye using ammonium having a long-chain alkylene group as a cation, it has high solubility in ethanol but low solubility in water. Therefore, when writing on paper, it is considered that the ethanol in the drawn line has a strong affinity with the paper to evaporate and is not dissolved in water, resulting in good water resistance. Furthermore, since the ink of the present invention uses ethanol, it has low odor and low toxicity, and is an ink with good safety for the human body.

Hereinafter, the ink composition of the present invention will be described with reference to Examples. Parts in the examples indicate parts by weight.

Example 1

[Chemical 6] 10 parts of the black dye represented by the above structural formula and an ethanol-soluble resin (Hitanol 2501: manufactured by Hitachi Chemical Co., Ltd.) 1
0 part was added to 80 parts of unmodified ethanol and stirred for 1 hour to obtain an ethanolic black ink for marking pen.

Example 2

[Chemical 7] 12 parts of the black dye represented by the above structural formula and an ethanol-soluble resin (Hitanol 2501: manufactured by Hitachi Chemical Co., Ltd.) 1
2 parts was added to 76 parts of unmodified ethanol and stirred for 1 hour to obtain an ethanolic black ink for marking pen.

Example 3

[Chemical 8] 8 parts of the black dye represented by the above structural formula and an ethanol-soluble resin (ketone resin K90: manufactured by Arakawa Chemical Industry Co., Ltd.) 12
Parts were added to 5 parts of benzyl alcohol and 75 parts of unmodified ethanol and stirred for 1 hour to obtain an ethanolic black ink for marking pens.

The ethanol black ink for marking pens obtained in Examples 1 to 3 was subjected to a stability test, a stability test with time, and a water resistance test to examine the ink characteristics. The results are shown in Table 1. The test was conducted by the following method. Ink stability: Each ink obtained in the example after stirring for 1 hour is sampled in spots, a few drops of the ink are dropped on Toyo Filter Paper No. 2, and the presence or absence of the precipitation of dye etc. is visually determined.
The case where no precipitation is observed is indicated by ◯, and the case where even a slight precipitation is observed is indicated by x. Stability over time: Each ink was placed in a glass bottle with a 100 ml tight stopper, left at -20 ° C and 60 ° C for 3 days, and spot tested (a few drops of the ink sampled from the bottom of the ink was dropped on Toyo filter paper No. 2), and visually checked. Determine the presence or absence of deposition of dyes. The case where no precipitation is observed is indicated by ◯, and the case where even a slight precipitation is observed is indicated by x. Water resistance: Drop each ink on Toyo Filter Paper No.2, air dry,
A few drops of pure water are dropped from a height of 3 cm, and the bleeding state is visually judged. ○ If bleed is not recognized,
The thing that is recognized even a little is marked with x.

[0021]

[Table 1] As described above, the ethanol-based marking ink of the present invention is excellent in ethanol compatibility of each component and has no precipitate,
An ink that is stable over time and has excellent water resistance.

[0022]

The ink for marking pens of the present invention is stable over time, has excellent water resistance, and does not cause phenomena such as dye deposition. Especially suitable for black ink. Also,
This ink is suitable for environmental safety as it has no toxicity or odor.

Claims (2)

[Claims] 1. A general formula: (Wherein R ¹ and R ² are alkyl groups having 1 to 4 carbon atoms, n is an integer of 1 to 5), a marking pen characterized by containing an ethanol-soluble resin and ethanol Ethanol-based ink. 2. An ethanol-based black ink for a marking pen according to claim 1.