JPH0827408A - Ink for color pencil lead - Google Patents

Abstract

PURPOSE:To obtain an ink for color pencil lead by using a long-chain dialkyl carbonate as a solvent for dissolving or dispersing the coloring substances in the pores in a porous lead fired at an elevated temperature, thus can be used as a lead for an automatic pencil because of its good appearance, drawn lines and writing feel. CONSTITUTION:This ink with which the leads for color pencils are pregnated, is produced by mixing a long-chain dialkyl carbonate of the formula (R, R' are each an alkyl of 12 or more carbon atoms) with a coloring substance at 70 deg.C to dissolve or disperse the colorant, as they are kept at the same temperature while thoroughly stirring. White leads made of boron nitride and clay are dipped in the ink, heated at 70 deg.C for 5 hours, washed with an organic solvent to remove off the excessive ink and dried at 50 deg.C for 12 hours to give leads for color pencils which are excellent in the change of appearance, drawn lines and writing feel with the passage of time and cause no corrosion of the chuck made of bronze or brass in the mechanism of an automatic pencil.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink for impregnating a color lead core of a firing type, and more particularly to an ink for impregnating a small diameter color lead core used in a mechanical pencil or the like.

[0002]

2. Description of the Related Art Conventionally, a white core obtained by extruding a kneaded product containing an organic polymer compound as a main component of a body material such as boron nitride and a binder such as clay, and then firing at a high temperature. It is already known to impregnate a pore of a body with an ink containing a dye to form a colored lead core.

However, this type of colored lead core is incompatible with the strength and the coloring density. If the porosity of the porous core is increased to increase the amount of ink impregnated, the coloring density is improved but the strength is inevitably decreased. On the contrary, if the porosity of the porous core is reduced to secure the strength, the impregnated amount of the ink is reduced and the color density is extremely lowered, which is not suitable for practical use. Therefore, in order to improve the color density, a non-volatile solvent such as oleic acid or glycerin fatty acid ester, which has a high solubility of the dye as an ink, is used.

[0004]

However, when the colored lead core is impregnated with the ink, the ink in the pores is in contact with the outside air, which causes a problem of aging. This is not only a non-volatile solvent or a solvent that dissolves and disperses a large amount of dye, but a solvent that does not change the viscosity and color of the solvent over time, as a result, retains the color tone and writing quality of the handwriting. It connects. In this sense, the solvent used in the conventional ink for color lead core cannot provide a sufficient solvent, and the color tone and the writing quality are deteriorated over a long period of time.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a colored lead core which has sufficient strength to withstand writing and exhibits excellent color density. That is, the coloring property and vividness of the coloring substance are remarkably improved.

From the above viewpoint, the present invention is characterized by using at least a long-chain dialkyl carbonate as a solvent in the color lead core ink, the structural formula of which is shown in Chemical formula 1.

[0007]

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This compound is characterized by having a carbonate structure of [-OCOO-], and is a synthetic lubricating oil base obtained from dimethyl carbonate and a higher alcohol as raw materials, as shown in Chemical Formula 2 below.

[0009]

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Here, R and R'are alkyl groups having 12 or more carbon atoms, and particularly those having 12 to 15 carbon atoms are preferably used. For example, Real Carbo SR- manufactured by Mitex Co., Ltd.
1000, SR-1000 / 12, Dialcarb M
-3, L-3, H-1, H-2 and the like.

In the present invention, these solvents may be used alone, or may be used in combination with other solvents, and the mixing ratio may be appropriately changed depending on the kind of the coloring substance or the characteristics of the ink. However, the solvent used in the present invention is preferably 10% or more, and more preferably 30% or more of the total solvent.

Solvents that can be used in combination include conventionally used solvents such as oleic acid, and the coloring substances used are preferably basic dyes, oil dyes, alcohol-soluble dyes, etc., but ultrafine pigments. A processed pigment and the like can also be used.

The colored lead core used in the present invention is a conventionally known calcined type colored lead core, which contains a body material such as boron nitride or talc.
A porous core obtained by extrusion-molding a kneaded material in which a binder such as clay and, if necessary, a pigment and an organic polymer compound is extruded and then fired at high temperature is used. Impregnate the ink with the solvent.

[0014]

Example 1 70 parts of long-chain dialkyl carbonate [Real Carbo SR-1000] (manufactured by Mitex) heated to 70 ° C. and 30 parts of Spiron Red C-GH (manufactured by Hodogaya Chemical Co., Ltd.)
Parts were added, and the mixture was sufficiently stirred while maintaining the temperature, and after filtration, a red ink was obtained.

Example 2 Long-chain dialkyl carbonate [Dialcarb H-1] 70 parts Victoria Pure Blue Base (manufactured by BASF) 30 parts The same as Example 1 except that the above materials were used instead of the materials of Example 1. To obtain a blue ink.

Example 3 Long chain dialkyl carbonate [Dialcarb H-2] 70 parts Oil orange 201 (manufactured by Orient Chemical Co.) 30 parts The same as Example 1 except that the above materials are used instead of the materials of Example 1. To obtain an orange ink.

Example 4 Long chain dialkyl carbonate [Dialcarb M-3] 40 parts Oleic acid 30 parts Oil Blue 613 (manufactured by Orient Chemical Co.) 30 parts A blue ink was obtained in the same manner as in Example 1.

Comparative Example 1 A red ink was obtained in the same manner as in Example 1 except that the long chain dialkyl carbonate [Real Carbo SR-1000] of Example 1 was replaced with sorbitan sesquioleate.

Comparative Example 2 A red ink was obtained in the same manner as in Example 1 except that polyoxyethylene monostearate was used in place of the long chain dialkyl carbonate [real carbon SR-1000] of Example 1.

Comparative Example 3 A red ink was obtained in the same manner as in Example 1 except that the long chain dialkyl carbonate [Real Carbo SR-1000] of Example 1 was replaced with glyceryl monocaprylate.

As described above, the white cores made of boron nitride and clay were dipped in the inks obtained in the respective Examples and Comparative Examples, and the inks were kept for 5 hours.
Warmed at 0 ° C. Next, the excess ink adhering to the surface of the white core impregnated with the ink is washed with an organic solvent, and 5
Each color lead core was obtained by drying at 0 ° C. for 12 hours.

[0022]

The colored lead cores using the ink for colored lead cores of the present invention all show clear handwriting and have a smooth writing taste.
The erasability with an eraser was also good. In particular, it was possible to obtain an ink with excellent lubricity, and the writing quality was better than ever. Further, the colored lead cores impregnated with the inks of the respective examples were left in a blast dryer at 60 ° C. for 60 days and then taken out to examine the state and the writing taste.
The colored lead core obtained in No. 3 had a crystal of a dye deposited on the surface, which made it difficult to feed it with a mechanical pencil, the writing was thin, and the writing quality was hard. The colored lead cores obtained in Examples 1, 2, and 3 showed no change in appearance, handwriting, and writing quality. As described above, the color lead core impregnated with the ink of the present invention has a good sliding feeling which has never been achieved, and does not corrode the phosphor bronze chuck and the brass chuck that are mechanical parts of the mechanical pencil at all, and can be used over time. It has an excellent feature that the initial performance can be maintained for a long time without significant change.

Claims (1)

[Claims] 1. A color characterized by using at least a long-chain dialkyl carbonate as a solvent for dissolving or dispersing a coloring substance in a colored lead core ink to be impregnated into pores of a porous core body obtained by firing at a high temperature. Ink for lead core.