KR20090073826A - Neutrality ink composition for marker pen and method of preparing the same - Google Patents

Abstract

A neutral ink composition for marker pens is provided to enable writing on a board made of non-absorbing material, to ensure excellent erasability after drying and fast drying rate compared with aqueous ink. A neutral ink composition for marker pens comprises distilled water 17.5-22.5 weight%, 95% alcohol 20-30 weight%, semi-synthetic cellulose polymer 3.5-6.5 weight%, coloring pigment 12.5-17.5 weight%, dioctyl adipate 12.5-17.5 weight%, emulsifier 5-9 weight%, pigment dispersant 2-4 weight%, stabilizer 1-3 weight% and releasing agent 6-10 weight%. The semi-synthetic cellulose polymer comprises methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, hydroxypropyl ethyl cellulose, carboxymethyl cellulose, carboxymethyl cellulose or their mixture.

Description

Neutrality ink composition for marker pen and manufacturing method therefor {NEUTRALITY INK COMPOSITION FOR MARKER PEN AND METHOD OF PREPARING THE SAME}

The present invention relates to a neutral ink composition for a marker pen and a method for manufacturing the same, and more particularly, to a neutral ink composition for a marker pen and a method for producing the same, which is superior to an aqueous ink and quick to dry, and which is harmless to humans and the environment than an oil ink.

Background Art Conventionally, blackboards used in classrooms, seminar rooms, conference rooms, and offices have black or green surfaces, and in recent years, green blackboards have been used to protect eyesight. And the like.

However, in the process of writing or erasing letters using chalk on the blackboard, a large amount of chalk powder is generated, causing the interior to be contaminated. In particular, the generated chalk powder penetrates into the human body during respiration and causes various lung diseases. Problems have arisen.

Due to the above problem, a colored marker pen used for a white board or the like is known, and the marker pen has an ink solution therein so that the ink solution is absorbed by an absorbent such as a sponge installed on the marker nib inside the marker pen. By letting out through the outside to have the function of writing instruments.

The white board has a white background color, and the marker pen writing on the surface is written using various colors with good erasure. However, if the background color is white, the eyes are easily tired due to the reflection of light, which causes blindness. There was a problem that the learning effect is reduced.

Accordingly, various techniques have been developed to solve the above problems.

As one example, Korean Patent Publication No. 0132292 (published June 2, 1990) includes (a) 50 to 90% by weight of water as a solvent, (b) 1 to 30% by weight of a colorant dissolved or dispersed in water, (c) (1) emulsions or hydrosols of polyvinyl acetate, vinyl acetate copolymers, alkyd resins or woody-carbon resins, and (2) water-soluble vinyl acetate copolymers, alkyd resins or urethane resins. 0.1 to 15% by weight of a film having a film-forming property at least one room temperature selected from the group consisting of (d) (1) a liquid nonvolatile aliphatic carboxylic phase ester at room temperature, (2) 1 to 20% by weight of an aqueous emulsion of at least one turbulent liquid hydrocarbon selected from the group consisting of liquid turbulent higher hydrocarbons at room temperature and liquid turbulent higher alcohols at normal temperature. Aqueous Giant discloses a marking pen ink composition.

However, the present invention has a problem that it takes a long time to dry the ink composition after writing because it is harmless to the human body and the environment compared to the oil ink composition but lacks fast-drying.

As another example, Korean Patent Publication No. 0133125 (published Dec. 22, 1995) contains 9 to 12% by weight of titanium oxide and 1 to 1.5% by weight of calcium carbonate, followed by 1.5 to 1.8% by weight of vinyl resin, 50 to 60% by weight of isopropyl alcohol (IPA) was mixed and heated in a hot bath at 95 to 110 ° C. for about 20 to 30 minutes to form a mucus stock solution, followed by 8 to 11% by weight of isooxystearate (IOS). 2.8 to 3.2% by weight of polyoxyethylene lauryl ether, 0.8 to 1.2% by weight of polyoxyethylene oleincetyl ether and 10 to 12% by weight of acetone were added and mixed, followed by 7 to 8.5% by weight of dioctyl adipate (DOA). Disclosed is a method for producing a white ink for a marker pen, which is added and mixed.

However, the present invention has a problem that harmful effects on the human body and the environment because it contains an environmental hormone effluent component such as isopropyl alcohol, isooctylstearate, ethylene. In addition, when writing on a green blackboard, the whiteness is reduced due to the function of isopropyl alcohol, so that the ink is not clear but is dimmed out.

Therefore, the 1st objective of this invention is to provide the neutral ink composition for marker pens which can improve quick-drying and can alleviate a human hazard.

It is a second object of the present invention to provide a method for producing a neutral ink composition for a marker pen, which can improve quick-drying and alleviate human hazards.

In order to achieve the first object of the present invention described above, according to an embodiment of the present invention 17.5 to 22.5% by weight of distilled water; 20% to 30% by weight of 95% alcohol; 3.5 to 6.5 wt% of semi-synthetic cellulose polymer; 12.5 to 17.5 weight percent of color pigments; Dioctyl adipate 12.5-17.5 weight percent; 5 to 9 weight percent emulsifier; 2 to 4 weight percent of a pigment dispersant; 1 to 3 weight percent of stabilizer; And it provides a neutral ink composition for a marker pen comprising 6 to 10% by weight of the release agent.

In order to achieve the above-described second object of the present invention, the manufacturing method according to an embodiment of the present invention (i) 46 to 60% alcohol 37.5 to 52.5% by weight and the semi-synthetic cellulose-based polymer 3.5 to 6.5% by weight Stirring at 60 to 78 ° C. for 8 to 12 hours; (Ii) adding 12.5 to 17.5% by weight of color pigment to the mixture resulting from step (iii) and grinding; (Iii) adding 12.5 to 17.5 wt% of dioctyl adipate and 5 to 9 wt% of an emulsifier to the mixture ground through step (ii) and stirring for 1 to 3 hours; And (iii) adding 2 to 4% by weight of the pigment dispersant, 1 to 3% by weight of the stabilizer and 6 to 10% by weight of the release agent to the mixture produced through step (iii), and stirring for 3 to 5 hours. Provided is a method for preparing a neutral ink composition for a marker pen.

According to the present invention, the neutral ink composition for the marker pen can be written on a writing board of a non-absorbent material such as a green board, a white board, glass, a fine wood or plastic board, and is erased by erasing it with an eraser after drying. After the writing, the color remains clear, harmless to the human body and the environment compared to the oil ink, and has a quick drying effect compared to the aqueous ink.

Hereinafter, a neutral ink composition (hereinafter, referred to as an "ink composition") for a marker pen according to preferred embodiments of the present invention and a manufacturing method thereof will be described in detail.

One embodiment of the present invention relates to an ink composition, when the components contained therein are roughly divided into distilled water for adjusting the viscosity and dryness of the ink composition, alcohol combined with the distilled water to control the drying time of the ink composition, Semi-synthetic cellulose-based polymer combined with the distilled water and alcohol to increase the viscosity of the ink composition, a color pigment representing a color, and dioctyl adipate to prevent coagulation so that the written ink composition can be easily erased. : DOA), an emulsifier for softening the ink composition, a pigment dispersant for dispersing the color pigments of the ink composition without aggregation, a stabilizer for maintaining a constant viscosity and shape retention of the ink composition, and the ink Release agents are used that allow the composition to separate well from the board.

Each of these components may perform a single function like a pigment, but may also function jointly through a chemical action with each other, which is natural due to the nature of the chemical. Therefore, the present invention may be said to be specific in the combination of the various compositions and the amount thereof, rather than only depending on the specific functional ingredient.

The ink composition according to an embodiment of the present invention includes distilled water.

The distilled water is a solvent of the ink composition, adjusts the viscosity and dryness of the ink composition, and controls the transfer performance of the ink composition. At this time, the amount of distilled water used is not particularly limited, and may be adjusted according to the kind and amount of other components, the viscosity of the target ink composition, and the like. The amount of distilled water used may be selected from a wide range, such as 15 to 50% by weight, preferably 17.5 to 22.5% by weight.

When the content of distilled water is used in the ink composition is less than 17.5% by weight, the viscosity of the ink rises above the appropriate viscosity, making writing on the writing board through the nib difficult, and when used in excess of 22.5% by weight, the viscosity of the ink is reduced to Excess spillage or separation rate of the color pigment and semi-synthetic cellulose-based polymer is faster than the ink composition containing an appropriate level of distilled water is difficult to long-term storage. In addition, when excess distilled water is used, the drying rate of the ink used after writing becomes slower than the ink composition containing the appropriate level of distilled water.

The ink composition according to one embodiment of the present invention contains an alcohol.

The alcohol may be combined with the distilled water to control the drying time of the ink composition, and may be mixed with the distilled water to form an alcohol having 45 to 60% purity, but may be used as any alcohol. It is recommended to use% alcohol. At this time, the 95% alcohol is preferably contained 20 to 30% by weight.

Here, the drying time of the written ink composition when the content of the 95% alcohol is less than 20% by weight is increased than when using an appropriate amount of alcohol, and the written ink when the content of the 95% alcohol is more than 30% by weight. The drying time of the composition is reduced compared to the case of using an appropriate amount of alcohol, but due to the characteristics of the alcohol lowers the viscosity of the entire ink, a phenomenon such as precipitation of color pigments, etc. occurs, resulting in deterioration of the long-term storage of the ink.

Ink composition according to an embodiment of the present invention comprises a semi-synthetic cellulose-based polymer.

The semisynthetic cellulose-based polymer is converted into a resin form by mixing with the distilled water to promote dispersion of the pigment, prevent precipitation of the pigment, and impart adhesion to the writing plate, so that the ink composition is uniformly coated on the writing plate, The ink composition is maintained at a constant viscosity. In addition, the amount of the semi-synthetic cellulose-based polymer is not particularly limited, and the amount of the semi-synthetic cellulose polymer may be controlled according to the constituents of the ink composition, but preferably about 3.5 to 6.5 wt%.

Here, when the content of the semi-synthetic cellulose-based polymer is less than 3.5% by weight, the color pigments are not uniformly distributed in the ink composition, are concentrated in one direction so that a large amount of color pigments do not leak or leak during writing, and the viscosity is thin. Precipitation of the lower color pigment may promote separation of the pigment and the semi-synthetic cellulose polymer. In addition, when the content of the semi-synthetic cellulose-based polymer is more than 6.5% by weight, the viscosity is increased to prevent the separation of the pigment to some extent, but the fluidity of the color pigment in the ink composition is reduced, so that the ink flow through the pen tip is not uniform. In writing, writing becomes insufficient and at the same time the written ink composition is not easily erased.

In this case, as the semi-synthetic cellulose polymer, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, hydroxypropyl ethyl cellulose, carboxymethyl cellulose or a mixture of two or more thereof may be used. Preferably, methyl cellulose is used.

The methyl cellulose is synthesized by acting dimethyl sulfuric acid on the cellulose in the presence of alkali, various methyl cellulose having a different degree of substitution is produced according to the production conditions. Generally a white solid, but slight differences occur depending on the degree of methylation. Methyl cellulose with a degree of substitution of 0.1 to 0.9 (2 to 16% of OCH ₃ ) is dissolved in 4 to 10% aqueous sodium hydroxide solution, and methyl cellulose with a degree of substitution of 1.6 to 2.0 (26.5 to 32.6% of OCH ₃ ) is dissolved in cold water. Methyl cellulose having a solubility of 2.4 to 2.6 (34 to 38% of OCH ₃ ) is dissolved in an organic solvent to form a viscous solution.

The ink composition according to an embodiment of the present invention includes a color pigment.

The color pigment is added to impart a color to the ink composition, and any color pigment may be used as long as it is harmless to humans and the environment, but preferably titanium dioxide, white carbon, calcium carbonate, precipitated magnesium carbonate, or organic pigment. Or mixtures of two or more thereof is preferably used, and more preferably titanium dioxide. At this time, the color pigment is preferably contained 12.5 to 17.5% by weight.

Herein, when the content of the color pigment is less than 12.5% by weight, the color of the ink composition is not clear, the written ink composition is not easily erased, and when the content of the color pigment is more than 17.5% by weight, the color is clear. The viscosity of the ink composition is increased so that the ink composition does not flow out evenly through the nib.

The titanium dioxide has the largest coloring power and hiding power among color pigments, and has acid resistance, alkali resistance, light resistance, heat resistance, etc., and its usage amount is the most among color pigments, paint, rubber, printing ink, papermaking, seal, synthetic resin, and coloring. , Cosmetics, enamel (琺 瑯) has a variety of uses.

An ink composition according to an embodiment of the present invention includes dioctyl adipate.

The dioctyl adipate prevents coagulation so that the written ink composition can be easily erased, and preferably 12.5 to 17.5 wt%. In this case, when the content of the dioctyl adipate is less than 12.5% by weight, the written ink composition is smeared or flowed down, and when the content of the dioctyl adipate is more than 17.5% by weight, the written ink composition is easily coagulated. Not erased.

The ink composition according to an embodiment of the present invention includes an emulsifier.

The emulsifier helps to form a coating film by softening the ink composition and imparts scavenging properties to the ink composition. Any emulsifier used for this purpose may be included in the emulsifier. Higher fatty acid esters such as glycerin fatty acid ester, isostearic acid isetyl and isocetyl palmitate, polyhydric alcohol fatty acid esters, higher aliphatic hydrocarbons, polyoxyethylene alkyl ether type nonionic surfactants and derivatives thereof, and polyoxyethylene alkylphenyl It is preferable to use an ether type nonionic surfactant and derivatives thereof, a phosphate ester surfactant or a mixture of two or more thereof, and preferably a glycerin fatty acid ester in the range of 2.8 to 3.5 HLB (Hydrophilic Lipophlic Balance). good. Here, the emulsifier is preferably included in about 5 to 9% by weight.

In this case, when the content of the emulsifier is less than 5% by weight, the fluidity of the ink composition may be lowered. When the content of the emulsifier is more than 9% by weight, the flexibility of the ink composition may be improved, but the color pigment may be reduced due to the decrease in viscosity of the ink composition. Are entangled with each other, and after writing, a residue may remain on the letters, causing the ink composition to bleed or flow, causing stains on the writing surface.

Ink composition according to an embodiment of the present invention comprises a pigment dispersant.

The pigment dispersant is to promote the dispersion of the pigment to inhibit the precipitation of the pigment and the separation of the semi-synthetic cellulose polymer, and to maintain the color development and shelf life, any pigment dispersant used for this purpose is Although it will be referred to as a pigment dispersant, it is preferable to use a pentastearate-based material, and in particular, to use a polyoxyethylene sorbitan monooleate.

At this time, the pigment dispersant is preferably contained about 2 to 4% by weight. In this case, when the content of the pigment dispersant is less than 2% by weight, as the dispersing effect of the pigment is lowered, the pigment may be separated and the shelf life of the ink may be shortened, and the pigment may not uniformly flow out of the marker pen. When the content of the dispersant is more than 4% by weight, the dispersion of the pigment is smooth but may work with the release agent to gel or deteriorate the ink composition by gelling the ink composition.

The ink composition according to an embodiment of the present invention includes a stabilizer.

The stabilizer is to maintain a constant viscosity and shape retention of the ink composition, as long as the stabilizer used for the purpose, any stabilizer and surfactant may be used, but preferably ETHOXYLATED NONYLPHENOL Is good to use.

At this time, the stabilizer is preferably included in about 1 to 3% by weight. Here, when the content of the stabilizer is less than 1% by weight, the white pigment and the semi-synthetic cellulose-based polymer may be layered in a short time so that the ink composition may be clogged at the nib, and when the content of the pigment dispersant is greater than 3% by weight. Erasability of the ink composition may be lowered.

An ink composition according to an embodiment of the present invention includes a release agent.

The release agent is to improve the eraseability of the ink composition coating so that the coating of the ink composition formed on the writing board can be easily erased by an eraser, and the material which plays an important role in the eraseability together with the semisynthetic cellulose-based polymer and an emulsifier to be. The releasing agent may be an undried oil such as castor oil, camellia oil, olive oil, palm oil, palm oil, mineral oil such as liquid paraffin, spindle oil, light oil, kerosene, machine oil, lubricating oil, synthetic oil, or an olefinic hydrocarbon or aromatic hydrocarbon. Petroleum solvents, such as these, can be used, Preferably palm oil is used. At this time, the release agent is preferably contained 6 to 10% by weight.

Here, when the content of the release agent is less than 6% by weight, the release effect of the ink is weak so that it is not easily erased by the eraser, and when the content of the release agent is more than 10% by weight, the ink is reacted and gelated by the pigment dispersant administered. This hinders the outflow and lowers the scavenging ability.

The present invention provides a method for producing an ink composition comprising the above-described configuration.

1 is a flow chart showing the manufacturing process of the manufacturing method of the ink composition according to the present invention.

Referring to Figure 1, the manufacturing method of the ink composition according to the present invention is as follows.

First, 37.5 to 52.5% by weight of 46 to 60% alcohol and 3.5 to 6.5% by weight of the semisynthetic cellulose polymer are mixed and stirred at 60 to 78 ° C. for 8 to 12 hours to prepare a first mixture, and then to the first mixture. 12.5 to 17.5% by weight of color pigments are added and milled to form a second mixture.

Then, 12.5 to 17.5 wt% of dioctyl adipate and 5 to 9 wt% of an emulsifier are added to the second mixture ground through the above step, and stirred for 1 to 3 hours to prepare a third mixture, followed by the third mixture. 2 to 4% by weight of the pigment dispersant, 1 to 3% by weight of the stabilizer and 6 to 10% by weight of the release agent are added, and stirred for 3 to 5 hours to prepare an ink composition.

The first step is to mix 37.5 to 52.5% by weight of 46 to 60% alcohol and 3.5 to 6.5% by weight of semi-synthetic cellulose polymer. The alcohol and the semi-synthetic cellulose polymer are added to a stirrer and 60 to 78 ° C Mixing for 8-12 hours in temperature range forms the first mixture. At this time, the stirring speed of the stirrer may be performed at 1,000 to 1,500 rpm.

If necessary, the method may further include mixing 17.5 to 22.5 wt% of distilled water and 20 to 30 wt% of 95% alcohol to prepare 46 to 60% alcohol before the step.

The second step is to add 12.5 to 17.5% by weight of the color pigment to the first mixture produced through the first step, wherein the color mixture is added to the first mixture to form a second mixture and then the second mixture is added. Crush with a grinder. In this case, as the grinder, as long as it is commonly used in the art, any one may be used, but it is preferable to use a three roll mill, a stand mill, a jet mill, or the like.

When the second mixture is pulverized using the sambon roll mill, the second mixture may be pulverized by performing the sambon roll mill 2 to 4 times, preferably 2 times.

When the second mixture is ground using the stand mill or jet mill, the second mixture is preferably ground for 1 to 3 hours, preferably about 2 hours.

The third step is to add 12.5 to 17.5 wt% of dioctyl adipate and 5 to 9 wt% of emulsifier to the second mixture ground through the second step, and add the dioctyl adipate and emulsifier to the second mixture. Add and stir at room temperature for 1-3 hours to form a third mixture. At this time, the stirring speed of the stirrer may be performed at 1,000 to 1,500 rpm.

The fourth step is to add 2 to 4% by weight of the pigment dispersant, 1 to 3% by weight of the stabilizer and 6 to 10% by weight of the release agent to the third mixture produced through the third step, wherein the pigment dispersant, Stabilizer and mold release agent are added and mixed by stirring at room temperature for 3 to 5 hours. At this time, the stirring speed of the stirrer may be performed at 1,000 to 1,500 rpm.

Hereinafter, the present invention will be described in detail with reference to a preferred embodiment. However, the following Example is for illustrating this invention concretely, It does not limit only to this.

Example 1

1. Under 1 atmosphere of room temperature, 20 kg of distilled water and 25 kg of 95% alcohol (Korea Co., Ltd., Korea) were added to a reactor and stirred at 1,300 rpm for 3 hours to prepare 52.8% alcohol.

2. Under 70 [deg.] C. 1 atm, 5 kg of methyl cellulose [Viscochem, China] was added to the reactor in 52.8% alcohol and stirred at 1,300 rpm for 10 hours to form a first mixture.

3. At room temperature under 1 atm, 15 kg of titanium dioxide [R-906, DuPont, USA] was added to the first mixture to form a second mixture, and the second mixture was ground twice using a sambon roll mill.

4. At room temperature under 1 atm, 10 kg of dioctyl adipate [Monaplex® DOA, CP HALL COMPANY, USA] and 15 kg of glycerin fatty acid ester [Excel P-40, Cao Corporation, Japan] were added to the milled second mixture. To form a third mixture, which was stirred at 1,300 rpm for 2 hours to form a third mixture.

5. Under a pressure of 1 atm, 3 kg of polyoxyethylene sorbitan monooleate [Tween 80, UNIQEMA, USA] as a pigment dispersant and ethoxylated nonylphenol [NPE-10, Honam Petrochemical, Korea] and palm oil [MOI, Malaysia] were added and stirred at 1,300 rpm for 4 hours to prepare a neutral ink composition for a marker pen.

Experimental Example

Fast drying test

At room temperature and humidity of 60 to 70%, a non-absorbing and rough surface of a clean green chalkboard and stopwatch is prepared, the green chalkboard is placed at an angle of 70 ㅀ from the bottom, and the ink composition prepared by the present invention is injected into a pen. After taking a circle having a diameter of about 30 cm, the time was measured for how long the written line was completely dried within a few seconds.

As a result of testing the ink composition prepared in Example 1 according to the above-described physical property test method, the ink composition has a drying time of about 10 seconds after writing, which is longer than a drying time of about 8 seconds, which is a drying time of a general oil ink composition. However, since the drying time was reduced by about 10 seconds or more than the drying time of the general aqueous ink composition, which is about 20 seconds, the quick drying was evaluated as good.

In addition, the ink composition was evaluated to mitigate human hazards because the environmental hormone bleeding component contained in the component is used smaller than the general oil ink composition.

As described above, the present invention has proved its superiority through the above embodiments, but the present invention is not necessarily limited only to the above embodiments, and various substitutions may be made without departing from the technical spirit of the present invention. , Modifications and variations are possible.

1 is a flowchart illustrating a manufacturing process of a neutral ink composition for a marker pen according to an embodiment of the present invention.

Claims (9)

17.5 to 22.5 weight percent of distilled water; 20% to 30% by weight of 95% alcohol; 3.5 to 6.5 wt% of semi-synthetic cellulose polymer; 12.5 to 17.5 weight percent of color pigments; Dioctyl adipate 12.5-17.5 weight percent; 5 to 9 weight percent emulsifier; 2 to 4 weight percent of a pigment dispersant; 1 to 3 weight percent of stabilizer; And 6 to 10 weight percent release agent; Neutral ink composition for a marker pen comprising a. According to claim 1, wherein the semi-synthetic cellulose polymer is composed of methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, hydroxypropyl ethyl cellulose, carboxymethyl cellulose or a mixture of two or more thereof A neutral ink composition for a marker pen, characterized in that. The neutral ink composition of claim 1, wherein the color pigment is titanium dioxide, white carbon, calcium carbonate, precipitated magnesium carbonate, barium sulfate, organic pigments, or a mixture of two or more thereof. The neutral ink composition of claim 1, wherein the emulsifier is a glycerin fatty acid ester having an HLB of 2.8 to 3.5. The method of claim 1, wherein the pigment dispersant is propyl myristate, butyl palmitate, butyl stearate, dodecanedioic acid dioctyl ester, dipropyl adipate, dioctyl sebacate, dioctyl azelate, propylene glycol monostearate, Propylene glycol didecanoate, natural or synthetic fatty acid triglycerides, triisostearate, liquid paraffin, squalene, oxidized polyethylene wax, hexyl alcohol, octyl alcohol, lauryl alcohol, pentastearate series or mixtures of two or more thereof Neutral ink composition for marker pens. The neutral ink composition of claim 1, wherein the stabilizer is ethoxylated nonylphenol. The marker pen according to claim 1, wherein the release agent is palm oil, castor oil, camellia oil, olive oil, palm oil, liquid paraffin, spindle oil, light oil, kerosene, machine oil, lubricating oil, synthetic oil, olefinic hydrocarbon, or aromatic hydrocarbon. Neutral ink composition. (Iii) mixing 37.5-52.5% by weight of 46-60% alcohol and 3.5-6.5% by weight of semisynthetic cellulose polymer, and stirring at 60-78 ° C. for 8-12 hours;  (Ii) adding 12.5 to 17.5% by weight of color pigment to the mixture resulting from step (iii) and grinding; (Iii) adding 12.5 to 17.5 wt% of dioctyl adipate and 5 to 9 wt% of an emulsifier to the mixture ground through step (ii) and stirring for 1 to 3 hours; And (Iii) adding 2 to 4% by weight of the pigment dispersant, 1 to 3% by weight of the stabilizer and 6 to 10% by weight of the release agent, and stirring for 3 to 5 hours to the mixture produced through step (iii). Method for producing a neutral ink composition for pens. The neutral pen for the marker pen according to claim 8, further comprising preparing 46 to 60% alcohol by mixing 17.5 to 22.5 wt% of distilled water and 20 to 30 wt% of 95% alcohol before step (iii). Method for producing an ink composition.

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