JPS6017434B2 - Erasable ink composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an ink composition that can be erased with hydrochloric acid, and more specifically, an ink composition in which a chlorate is blended with one or more dyes selected from acid dyes. The present invention relates to a characteristic ink composition.

Various coloring agents are used in tools for writing letters and designs, such as signboards, pens, ballpoint pens, and trinkets, but in general, these colorants easily erase the written letters and designs. In order to prevent this from occurring, materials with good chemical fastness have been used.

However, if a coloring agent was developed that could easily erase the characters and designs once written, it would not only solve the problem of writing errors, but also erase the markings on documents and books by erasing them again. It is very convenient because it can be restored to its original pristine condition, and it can also be used for interesting purposes as a teaching tool for children or as a return smell for children.
It is also clear that it is suitable as a marking tool for sketching in embroidery. The object of the present invention is to provide an erasable ink composition that can be used in such various interesting applications or fields.

Conventionally, it has been known to use hypochlorite as an erasing liquid for erasing ink.

This subboxal chlorate is a strong oxidizing agent, and when used, it is possible to erase the coloring caused by dyes. Due to the action of hypochlorite remaining on the paper, written letters and designs are erased and cannot be written on again. On the other hand, in the case of an oxidizing agent weaker than subgrade chlorate, it takes a long time to erase the oxidizing agent, or it becomes impossible to erase the oxidizing agent, so that it does not provide a good erasing effect. In addition, it is impossible to use such a strong oxidizing agent, such as a subhydrochloric acid salt, by adding it to the dye in advance; in this case, the dye itself will be oxidized and decomposed and its color will be erased. The present invention focuses on the fact that the oxidizing power of chlorate increases in the presence of acid, and as a result of intensive research to develop an ink composition that can be erased by acid using this principle, It was discovered that acid dyes containing chlorate can be easily decolored by hydrochloric acid, and the present invention was completed.

The chlorate used in the present invention is represented by the general formula MCI03 (M is a cation), and any water-soluble salt can be used, such as sodium salt, potassium salt, calcium salt, magnesium salt, etc. A wide range of metal salts are applicable.

The acidic dyes used in the present invention have acid groups such as sulfonic acid groups and carboxyl groups, and all of them are sodium salts thereof.

The acid dye used in the present invention is not decomposed by the action of the chlorate even if a chlorate is mixed therein, and is decomposed only by further action of hydrochloric acid on this mixture.

That is, the ink composition comprising an acid dye containing chlorate according to the present invention is stable unless exposed to hydrochloric acid, and exhibits coloration due to the dye; The oxidizing power of the chlorate increases significantly, causing the dye to decompose and lose its color. When erasing characters and designs written with the ink composition according to the present invention, the written characters and designs can be erased using an acid such as sulfuric acid, as is clear from the above, but in the case of the present invention, Preference is given to using hydrochloric acid. In other words, ``In the case of hydrochloric acid, chlorate and hydrochloric acid react and easily generate chlorine dioxide, chlorine, etc., and this generated substance has the effect of dissolving the color of the dye, and furthermore, hydrogen chloride in hydrochloric acid Because it is a volatile substance, after letters and designs written on paper are erased with hydrochloric acid, the hydrogen chloride remaining on the paper is dissipated and removed, leaving the erased traces clear without being erased again. This is because the ink composition according to the present invention is usually applied in the form of an aqueous solution, and the concentration of the components is from 0.1 to 20% by weight, preferably from 0.1 to 20% by weight with respect to the dye. 1-1% by weight, for chlorate 1-3% by weight, preferably 5-2
% by weight.

The concentration of hydrochloric acid used to erase the coloring of this ink composition is 1 to 30% by weight, preferably 4 to 2% by weight. Glycerin, alkylene glycol, polyalkylene glycol, etc. can be added to the ink composition of the present invention or to the hydrochloric acid used as an erasing agent to prevent drying during storage, and the amount added is 1 to 3% by weight. %, preferably 3 to 15% by weight. The ink composition of the present invention is usually applied as an aqueous ink, but can be applied as an oil-based ink if necessary.

To prepare an oil-based ink, an organic solvent such as phenyl glycol, benzyl alcohol, or ethyl alcohol can be used as a solvent. The ink composition of the present invention includes:
Signs, markers, ballpoint pens,
It is said to be a pen-shaped brush that is stored in the ink storage part of a fountain pen, etc., supported by the pen shaft, and exudes from the tip of the pen, as well as fine solids such as clay and staghorn.
By mixing with reinforcing and forming aids such as hydrogenated oil, stearic acid, and higher fatty acid metal salts, and forming and solidifying,
It can be dispersed and supported in a solid substance to make chalk or crayon-type brushes, and it can also be dispersed in an appropriate thickener and coated and laminated on the paper surface to make chalk paper or copy paper. .

In addition, the ink composition according to the present invention can also be applied in the form of microcapsules for chalk- and crayon-type brushes and paper-type coloring materials. In any case, in the present invention, the ink composition is supported on a suitable support and used as a tool for writing characters, figures, designs, etc. The erasing agent used for erasing the ink composition of the present invention is also used in the same way as the above ink composition, usually in the form of a brush housed in the ink accommodating part of a pen, etc., but its shape is particularly limited. It is not restricted and can be used in any appropriate form depending on the usage.

In order to erase characters or designs written using a writing tool containing the ink composition of the present invention, the written items may be treated with an erasing agent containing hydrochloric acid.

In this erasing process, the chlorate contained in the ink composition and the hydrochloric acid from the erasing agent react to generate diacid chlorine, chlorine, etc., thereby erasing written characters and designs. The remaining hydrochloric acid also evaporates over time. In the case of the present invention, since hydrochloric acid, which has an erasing effect, has been evaporated and removed from the erased trace, characters or designs can be written on the erased trace again. In the case of the present invention, it is particularly advantageous that the chlorate used, unlike the conventional hypochlorites, has a relatively weak action and is stable, even when mixed with dyes. It does not react with dyes unless exposed to acid, and furthermore, it does not discolor the paper or cloth on which it is written.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 Ink composition: 90 parts of water + 10 parts of ethylene glycol +
Acid violet music 2 times + sodium chlorate 10 times Erasing liquid: 7% hydrochloric acid 95 times + ethylene glycol 5 times Both the above ink composition and eraser were used as ink for sign marks and impregnated into the middle line of each sign mark, respectively. The liquid is leached from the pen core.

Next, letters (purple) were written on the paper with a marker containing the ink composition of the present invention, and then the written letters were traced with a marker containing an erasing liquid.

As a result, the purple letters written on the paper were erased.
Next, when the erased area is completely dry, when letters are written on it again with a signboard containing the ink composition of the present invention, the letters will not be erased and will turn a clear purple color. was colored. Example 2 Ink composition: Water 9
M10 polyethylene glycol (molecular weight 200) 10+
2 parts of dye + 12 parts of sodium chlorate Erasing liquid: 8% hydrochloric acid 95 parts and 10 parts ethylene glycol 5 parts We investigated the effects.

Next, after the erased area had dried, letters were written on it again with a marker containing the ink composition, and the recoloring effect was examined. The results are shown in the table below. As is clear from the results shown in the table above, the ink composition of the present invention can be easily erased after writing, and colored characters can be written again after the erasure.

Claims (1)

[Claims] 1. An ink composition whose color can be erased with hydrochloric acid, which is characterized in that a chlorate is blended with one or more dyes selected from acid dyes.