JP2000129188A - Double coloring ink composition and writing material using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a double coloring ink composition having stable double coloring effect for long time and excellent in storage stability by including a metal powderpigment, water, a specified water-soluble organic solvent and a specified aqueous dye. SOLUTION: This composition includes (A) preferably 4-15 wt.% metal powder pigment waterproofed partially or wholly such as aluminum-based or the like, (B) water, (C) preferably 5-30 wt.% at least one water-soluble organic solvent selected from alcohols having a breached hydrophobic group, glycols and glycol ethers such as dipropylene glycol monopropyl ether and (D) preferably 1-5 wt.% at least one water-soluble dye selected from among anthraquinone dye, carbonium-based dye and metal complex dye and, preferably, furthermore (E) preferably 0.1-30 wt.% water-soluble resin such as gelatin and has 1,000-10,000 mPa.s viscosity and pH 5-10. It is preferable to use the composition for an aqueous ball-point pen or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dual color ink composition and a writing instrument using the same. The present invention also relates to a method for forming a color using the composition.

[0002]

2. Description of the Related Art When a double color ink is used for writing, a contour line is further formed around the handwriting to obtain a double color handwriting (a border as shown in FIG. 1A). And used as ink for marking pens, felt-tip pens and the like.

Heretofore, a double color ink has been composed of, for example, a metal powder pigment, a water-soluble dye, water and a permeable organic solvent, and is used for writing on a solvent-permeable surface of paper, cloth, etc., and is formed of a metal powder pigment. As shown in FIG. 1 (B), there is known a dual color ink composition in which a water-soluble dye penetrates and diffuses around a handwriting to produce a contour effect (Japanese Patent Application Laid-Open No. Sho 60-2).
31777, JP-A-61-123684).

[0004] As described above, all of the currently used double color inks utilize a double color formation mechanism as shown in FIGS. 1A and 1B. As a coloring component, two types of a coloring agent that penetrates into paper or the like and a coloring agent that does not penetrate, that is, a water-soluble dye and a metal powder pigment are the mainstreams in the dual color ink composition.

[0005]

However, there is still room for improvement in the long-term stability of the dual color ink composition containing a water-soluble dye and a metal powder pigment.
That is, after the dual color ink composition is prepared, the metal powder pigment is ionized with time during storage thereof, and the water-soluble dye may be reduced in the process of ionization. The reduced water-soluble dye completely loses its color-forming properties or exhibits a color different from the initial color (before storage), resulting in a situation in which a double coloring effect cannot be obtained.

The present invention has been made based on such findings, and it is a main object of the present invention to provide a dual color ink composition which can provide a stable double color effect over a long period of time.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the problems of the prior art, and as a result, have found that an ink having a specific composition can achieve the above object.
The present invention has been completed.

That is, the present invention relates to the following dual color ink composition and a writing implement using the same.

1. (1) metal powder pigment, (2) water, (3)
At least one water-soluble organic solvent of alcohols, glycols and glycol ethers having a branched hydrophobic group, and (4) at least one water-soluble dye of anthraquinone dye, carbonium dye and metal complex salt dye. A dual color ink composition comprising:

[0010] 2. A writing instrument using the composition according to the above item 1 as an ink.

3. A color forming method, wherein at least a part of a handwriting drawn on an absorbing surface using the ink composition according to the above item 1 is rubbed with an eraser to remove a metal powder pigment.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Double Color Ink Composition The double color ink composition of the present invention comprises (1) a metal powder pigment,
(2) water, (3) at least one water-soluble organic solvent of alcohols, glycols and glycol ethers having a branched hydrophobic group, and (4) anthraquinone dye, carbonium dye and metal complex dye. It contains at least one water-soluble dye. -Metal powder pigment The metal powder pigment is not particularly limited as long as it has a metallic luster, and examples thereof include aluminum pigments and brass pigments. Examples of the aluminum pigment include “Alpaste WJP-U75C”, “Alpaste WE1200”, “Alpaste WXM7675”,
“Alpaste WXM0630” (all made by Toyo Aluminum), “1110W”, “2172SW” (all,
Showa Aluminum), “AW-808C”, “AW7
000R "(all manufactured by Asahi Kasei). Examples of the brass pigment include “BS-605” and “BS-60”.
7 (manufactured by Toyo Aluminum), "Bronze Powder P-555", and "Bronze Powder P-777" (manufactured by Nakajima Metal Foil & Powder Co., Ltd.). Also, "F
500RG-W "," F500BG-W "," F701
Colored aluminum pigments such as "GR-W" and "F701RE-W" (all manufactured by Showa Aluminum) can also be used.
These can be used alone or in combination of two or more.
The particle size of the metal powder pigment can be appropriately selected according to the type of the pigment.

Among these metal powder pigments, those which have been subjected to a water-resistant treatment are preferred. The water resistance treatment can be performed by a known method. For example, a pigment treated with a phosphoric acid-containing solution can be used, and a commercially available product can also be used. Examples of commercially available products include “Alpaste WXM0630” (manufactured by Toyo Aluminum).

More specifically, aluminum flakes and P or P supplied from inorganic phosphoric acid (one or more of orthophosphoric acid, pyrophosphoric acid, triphosphoric acid, tetraphosphoric acid, phosphorous acid, etc.) are used.
Is an aliphatic compound having at least one functional group (preferably having 8 to 50 carbon atoms) in a molecule of 500 to 10000 ppm with respect to the weight of aluminum and 0.3 to 5 parts by weight with respect to 100 parts by weight of aluminum ( For example, 2-ethylhexylamine, caprylamine, decylamine, laurylamine,
Aliphatic amines such as myristylamine, palmitylamine, stearylamine and oleylamine; aliphatic alcohols such as lauryl alcohol and stearyl alcohol; aliphatic amides such as oleic amide and stearamide; methyl oleate and butyl stearate Fatty acid metal salts such as sodium laurate and calcium oleate, and one or more kinds of orthophosphate esters such as dilauryl acid phosphate), 0.05 to 10 parts by weight of water, 100
1 part by weight of hydratable alcohol (one or more kinds of ethanol, isopropanol, isobutanol, isoamyl alcohol, ethyl cellosolve, butyl cellosolve, polyoxyethylene glycol, polyoxypropylene glycol) and 1 to 70 parts by weight of hydrocarbon Aluminum flake pigment compositions for water-based paints containing oil (one or more of mineral spirits, solvent naphtha, etc.) (JP-A-63-54475) can be preferably used.

The content of the metal powder pigment can be appropriately determined according to the kind of the pigment to be used and the like, but is usually about 4 to 15% by weight (as metal powder) in the ink composition of the present invention, particularly 5 to 10%. % By weight (as metal powder). If the content of the metal powder exceeds 15% by weight, the solid content increases, which may adversely affect viscosity, fluidity, and the like.
If the amount is less than 4% by weight, the hiding power of the pigment becomes insufficient, and the double coloring effect may not be obtained. Therefore, in the present invention, the metal powder pigment may be contained so that the metal powder accounts for about 4 to 15% by weight of the ink composition. -Water-soluble organic solvent As the water-soluble organic solvent, at least one of alcohols, glycols and glycol ethers having a branched hydrophobic group is used.

The structure having a branched hydrophobic group in the water-soluble organic solvent of the present invention means a structure in which a hydrophobic group is bonded to a main chain as a side chain in a chain compound.
The type of the hydrophobic group may be any of a methyl group, an ethyl group, and the like. The molecule may have one or two or more hydrophobic groups in the molecule, and when it has two or more, they may be the same or different. For example, in the case of hexylene glycol represented by the following formula, a structure having a methyl group in a dotted frame corresponds to a structure having “a branched hydrophobic group”.

[0017]

Embedded image

Of the above-mentioned water-soluble organic solvents, alcohols having a branched hydrophobic group include those of the general formula C _n
H _2n + 2 O: compounds represented by (n 4 to 6 integer), for example isobutanol, s- butanol, t-butanol (C _4), iso-pentanol, s- pentanol, t-
Pentanol, 3-pentanol, 3-methyl-2-butanol, 2-methyl-1-butanol (C _5), 2-
Ethyl butanol, 4-methyl-2-pentanol (C
₆ ) and the like.

Examples of glycols and glycol ethers having a branched hydrophobic group include 1,3-octylene glycol, hexylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, and poly (oxyethylene-oxypropylene). ) Derivatives, ethylene glycol monoisopropyl ether, propylene glycol monobutyl ether, propylene glycol monoethyl ether, dipropylene glycol monobutyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monomethyl ether and the like.

Among these water-soluble organic solvents, dipropylene glycol monopropyl ether, dipropylene glycol monomethyl ether, hexylene glycol and the like can be particularly preferably used.

The content of the water-soluble organic solvent can be appropriately determined according to the kind of the water-soluble organic solvent and the like, but is usually about 1 to 50% by weight, preferably 5 to 30% by weight in the ink composition of the present invention. %. Water-soluble organic solvent content of 50
If the amount is more than 10% by weight, the solubility of the water-soluble resin may be reduced to cause precipitation. When the content of the water-soluble organic solvent is less than 1% by weight, sufficient permeation and diffusion may not be obtained. -Water-soluble dye As the water-soluble dye, in the present invention, it is essential to use at least one of an anthraquinone dye, a carbonium dye and a metal complex dye. These dyes themselves,
Known or commercially available products can be used as they are.
In the present invention, it is preferable to use at least one of a carbonium dye and a metal complex dye among these dyes.

The anthraquinone dye may be any dye having an anthraquinone skeleton, and includes anthraquinone derivatives, anthrone derivatives and the like. For example, CIAcid
Blue 27, CIAcid Blue 43, CIAcid Green 25, C.
I.Basic Violet 25, CIBasic Blue 60, CIMordnt R
ed 11, CIAcid Red 83, CIDirect Green 28, CIM
ordant Blue 48 or the like can be used.

The carbonium dye is not particularly limited as long as it is based on carbonium ions.
In the present invention, diphenylmethane dyes, triphenylmethane dyes, xanthene dyes, acridine dyes and the like can be particularly preferably used. The diphenylmethane dyes include CIBasic Yellow 2, CIBasic Yellow 3, and CIBasic Yellow.
ic Yellow 37 and other triphenylmethane dyes
CIAcid Blue 90, CIAcid Green 16, CIAcid Viol
et 49, CIBasic Red 9, CIBasic Blue 7, CIAcid
Violet 1, CIDirect Blue 41, CIMordnt Blue 1,
CI as a xanthene dye such as CIMordnt Violet 1
Acid Yellow 74, CIAcid Red 52, CIAcid Violet 3
0, CIBasic Red 1, CIBasic Violet 10, CIMordn
t Red 27, CIMordnt Violet 25, etc., as acridine-based dyes, CIBasic Yellow 6, CIBasic Yellow 7,
CIBasic Orange 14, CIBasic Orange 15 and the like are respectively exemplified.

The metal complex dyes include metal complex dyes, dyes containing metals, and dyes capable of coordinating with metals. For example, as a dye capable of coordinating with a metal, an azo dye having an OH group, a COOH group, an NH ₂ group, or the like can be used. Examples of such azo dyes include CIMordant Red 30, CIMordant Yel
low 3, CIMordant Green 15, CIMordant Blue 13
And the like.

Among these metal complex dyes, copper phthalocyanine dyes, 1: 1 type metal complex dyes, 1: 2 type metal complex dyes and the like can be preferably used. Specifically, CIDirect Bl is a copper phthalocyanine dye.
ue86 and other 1: 1 metal complex dyes are CIAcid Ye
llow 54, CIAcid Orange 74, CIAcid Red 186, C.
I. Acid Violet 56, etc., as 1: 2 type metal complex dyes
CIAcid Yellow 59, CIAcid Black 60, CIAcid Re
d 296, CIAcid Blue 167 and the like.

The content of the water-soluble dye can be appropriately determined according to the kind of the water-soluble dye and the like, but is usually about 0.1 to 10% by weight, preferably 1 to 10% by weight in the ink composition of the present invention.
What is necessary is just 5 weight%. When the amount of the water-soluble dye exceeds 10% by weight, the viscosity and the fluidity may be adversely affected.
When the amount of the water-soluble dye is less than 0.1% by weight, a desired double coloring effect may not be obtained. -Water-soluble resin, etc. In the present invention, a water-soluble resin can be blended if necessary. The water-soluble resin is not particularly limited as long as it can impart viscosity and / or adhesiveness to the aqueous ink, and can be appropriately selected according to the purpose of use. For example, as a microbial polysaccharide or a derivative thereof, pullulan, xanthan gum, welan gum, ramzan gum and the like; guar gum, locust bean gum, pectin as a water-soluble plant polysaccharide or a derivative thereof, gelatin as a water-soluble animal polysaccharide or a derivative thereof, Casein and the like; cellulose derivatives such as hydroxyethyl cellulose, carboxymethyl cellulose (CMC), sodium salts and ammonium salts of celluloses such as hydroxypropyl cellulose; starch derivatives such as starch, cationic starch, dextrin and sodium starch glycolate; vinyl-based synthesis Polymers such as polyvinyl alcohol (PVA), polyvinyl pyrrolidone, and polyvinyl ether; and acrylic synthetic polymers such as sodium polyacrylate and carboxy Niruporima like; other polyethylene oxide as a synthetic polymer, methoxy ethylene-maleic acid copolymer or the like can be used. These can be used alone or in combination of two or more.

The content of the water-soluble resin can be appropriately determined according to the type of the water-soluble resin and the like, but is usually about 0.05 to 40% by weight, preferably 0.1 to 40% by weight in the ink composition of the present invention. What is necessary is just 30 weight%. If the amount of the water-soluble resin exceeds 40% by weight, writing may be difficult.
When the content of the water-soluble resin is less than 0.05% by weight, the predetermined addition effect may not be obtained.

In the ink composition of the present invention, other additives can be blended within a range not to impair the effect. For example, polyoxyethylene alkali metal salt as a lubricant,
Dicarboxylic acid amide, phosphate ester, N-oleyl sarcosine salt, etc .; polyhydric alcohol or a derivative thereof (glycerin, etc.) as a wetting agent; benzotriazole, tolyltriazole, dicyclohexylammonium nitrate, etc., as a rust preventive; Benzoisothiazoline, pentachlorophenol, cresol, etc.
In addition, various dispersants, surfactants and the like can be mentioned.

In the present invention, for example, NaCl, Na ₂ SO ₄
Etc. may be contained. In this case, the alkali metal salt in the ink composition is 1% by weight in total.
It is preferable to set the following. Alkali metal salts (especially Na
By adjusting the content of at least one of Cl and Na ₂ SO ₄ ), separation of the water-soluble organic solvent in the ink by salting out can be prevented, and more excellent temporal stability can be secured. The method for adjusting the content of the alkali metal salt is not particularly limited. For example, in the case of a dye, methanol,
It can be carried out by positively removing part or all of the alkali metal salt using ethanol or the like. When the content of the alkali metal salt is from 0 to 1% by weight from the beginning, it can be used as it is.

When the ink composition of the present invention is used for an aqueous ballpoint pen, the viscosity measured with an ELD type viscometer 3 ° (R14) cone 0.5 rpm (20 ° C.) is usually 1000 to 10000 mPa · s. It is preferred that it is about. By setting the ink viscosity in this range, particularly excellent temporal stability as an aqueous ballpoint pen,
Writability can be obtained. The ink viscosity can be adjusted with a water-soluble resin, water, or the like.

When the ink composition of the present invention is used for an aqueous ballpoint pen, the pH is usually preferably about 5 to 10. In particular, by setting the pH within this range, excellent temporal stability and the like can be ensured. The pH of the ink can be appropriately adjusted using a known pH adjuster such as sodium hydroxide and triethanolamine. The pH value is a value measured by a pH meter (20 ° C.).

The ink composition of the present invention can be prepared by a known dispersion method,
It can be prepared using a defoaming method, a filtration method and the like. For example,
After mixing and stirring water, a water-soluble dye and a metal powder pigment, a water-soluble resin is compounded, then a water-soluble organic solvent and various additives are compounded as needed, and sodium hydroxide, triethanolamine, etc. It can be obtained by adjusting the pH with a known pH adjuster. The mixing or stirring in each step may be performed using a known stirring device such as a dissolver, a mixer, or a kneader. Writing implement The ink composition of the present invention can be used as an ink for various writing implements, and can be used, for example, as a marker, a felt-tip pen, a ball-point pen, etc., and can be particularly preferably used as an aqueous ball-point pen ink. In the writing implement of the present invention, constituent elements of basically known writing implements (markers, water-based ballpoint pens, etc.) other than ink can be appropriately adopted.

In the case of a water-based ballpoint pen, for example, a known material and size can be applied to the ink container tube as it is. As the material, for example, a pipe made of a synthetic resin such as polyethylene or polypropylene, or a metal pipe can be used. The ballpoint pen may be assembled according to a known ballpoint pen assembly method.

As the ballpoint pen tip, the same material and structure as those used in known water-based ballpoint pens can be employed, but in particular, the difference between the ball diameter and the ball house inner diameter is usually 0.03 mm or more, especially 0.1 mm. 03-0.0
It is preferable for the ink composition of the present invention (the writing implement of the present invention) to use a ballpoint pen tip having a diameter of 4 mm. In the present invention, the above difference corresponds to a distance at a position where the distance between the ball and the inner surface of the ball house is closest. The difference between the ball diameter and the inner diameter of the ball house in a conventional ballpoint pen (ballpoint pen tip) is usually about 0.01 to 0.02 mm, but in the present invention, the ink of the present invention is particularly provided with a large difference of 0.03 mm or more. A good double coloring effect by the composition can be more reliably obtained. 3. Color-forming method The present invention also includes a color-forming method characterized in that at least a part of a handwriting drawn on an absorbing surface using the ink composition of the present invention is removed by rubbing with an eraser a metal powder pigment.

The handwriting drawn on the absorbing surface using the ink composition of the present invention basically has a double color developing action by the structure shown in FIG.

In the present invention, the size of the colored surface (dye surface) composed of “colorant + water-soluble organic solvent” in FIG. 1 (B) is infinitely large.
It can be close to that of. In other words, it is possible to control so that the dye surface and the metal surface almost coincide with each other. In this case, the appearance becomes almost one color to the naked eye, but such a state is also included in one embodiment of the present invention. The size of the dye surface can be adjusted by appropriately selecting the type of the water-soluble organic solvent to be used, the type of the absorbing surface, and the like.

The above-mentioned handwriting by the ink composition of the present invention is substantially removed only by rubbing with an eraser, and only the dye surface is left on the absorbing surface. As a result, the dye surface covered with the metal surface is also exposed, so that it is possible to obtain color development using only the dye. For example, when only a part of the handwriting is rubbed with an eraser, it is possible to create a variety of appearances consisting of a combination of double coloring and coloring only with dye,
Creation of various designs becomes possible.

The eraser is not particularly limited, and any commercially available eraser can be used. Further, the type (material) of the absorbing surface is not limited, and can be applied to any type of absorbing surface as long as the effects of the present invention can be obtained. For example,
Examples include papers, fibrous / woody materials, and cloths.

[0039]

According to the dual color ink composition of the present invention and a writing instrument using the same, in particular, a specific water-soluble organic solvent and a water-soluble dye are used for the metal powder pigment, so that the initial color formation can be maintained for a long period of time. Can be maintained. That is,
A stable double coloring effect can be obtained over a long period of time.

Further, according to the ink composition of the present invention, even when the aqueous ink is thickened, the colorant can be sufficiently penetrated and diffused into the writing surface to form an effective contour, and excellent double color formation can be achieved. The effect can be obtained.

Further, in the present invention, when the concentration of the alkali metal salt in the ink composition is adjusted, the separation of the solvent component in the ink can be more reliably prevented, and a more excellent double color-forming effect can be obtained. Can be maintained.

When handwriting with the ink composition of the present invention is rubbed with an eraser, substantially only the metal powder pigment is removed, so that color development with only the dye can be easily obtained.
A variety of designs can be created.

The dual color ink composition of the present invention can be used as an ink for various writing instruments, and is particularly suitable as an aqueous ballpoint pen ink. In addition, if a ballpoint pen tip having a specific structure is employed in the water-based ballpoint pen of the present invention, an optimum amount of ink can be secured, so that the double coloring effect of the ink composition of the present invention can be more reliably obtained.

[0044]

The present invention will be described more specifically with reference to the following Examples and Comparative Examples.

Examples 1 to 9 and Comparative Examples 1 and 2 Inks having the compositions shown in Table 1 were prepared. First, after mixing and stirring a predetermined amount of water, a water-soluble dye and a metal powder pigment, a water-soluble resin was blended and stirred at room temperature for 1 hour. Next, a water-soluble organic solvent, a wetting agent, a preservative, and a lubricant are mixed, and the ink composition is stirred for 1 hour at room temperature while adjusting the pH with a pH adjuster (triethanolamine, sodium hydroxide, etc.). Got each. The viscosity, pH, and concentration (% by weight) of the alkali metal salt of the obtained ink composition were measured. Table 1 shows the results.

The components shown in Table 1 are as follows. (1) Water-soluble dye-Water-soluble dye 1: xanthene dye ("CHGAI INK RED AM-5", manufactured by Chugai Chemical Co., CI Acid Red 87, salt content: about 2% by weight or less)-Water-soluble dye 2: Triphenylmethane dye ("ACID BLUE P1 conc." Manufactured by Sumitomo Chemical Co., Ltd., CI Acid Violet 21, salt content: about 5% by weight or less)-Water-soluble dye 3: 1: 1 type metal complex salt dye ("LANYL NAVIY") BLUE TW, manufactured by Sumitomo Chemical Co., Ltd., CI Acid Blue 193, salt content: about 10% by weight or less)-Water-soluble dye 4: 1: 2 type metal complex salt dye ("LANYL RED B" manufactured by Sumitomo Chemical Co., Ltd., C.I. Acid Red 215, salt content of about 10% by weight or less) Water-soluble dye 5: an azo dye capable of coordinating with a metal ("SUNCHROMINE FAST BL") UE MB, manufactured by Sumitomo Chemical Co., Ltd., CI Mordant Blue 13, salt content: about 10% by weight or less) Water-soluble dye 6: anthraquinone dye ("SUMINOL FAST PR conc.", Manufactured by Sumitomo Chemical Co., Ltd., CI Acid) Blue 129, salt content of about 10% by weight or less) Water-soluble dye 7: Copper phthalocyanine dye ("SUMILIGHT SUPRA TURQUAOISE BLUE" manufactured by Sumitomo Chemical Co., Ltd., CI Direct Blue 86, salt content of about 10% by weight or less) Dye 8: diphenylmethane dye ("AURAMINE EXTRA 0-125; 0-100" manufactured by Sumitomo Chemical Co., Ltd., CI Basic Yellow 2, salt content: about 10% by weight or less) Water-soluble dye 9: acridine dye ("SUMITOMO") ACRIDINE ORANGE N RK conc. ", Manufactured by Sumitomo Chemical Co., Ltd., CI Basic Orange 14, salt content: about 10% by weight or less.-Water-soluble dye 10: disazo dye (" SUMINOL MILLING SCARLEET G "manufactured by Sumitomo Chemical Co., Ltd .; CI. Acid Red 145, salt content of about 10% by weight or less) Water-soluble dye 11: monoazo dye ("SUMINOL FAST RED GG CONC" manufactured by Sumitomo Chemical Co., Ltd., CI Acid Red 19, salt content of about 10% by weight or less) The salt content indicates the concentration of the alkali metal salt in each water-soluble dye. Dyes other than water-soluble dyes 1 and 2 were used after removing salts using a solvent such as methanol or ethanol. (2) Water-soluble organic solvent-Water-soluble organic solvent 1: dipropylene glycol monopropyl ether (reagent)-Water-soluble organic solvent 2: dipropylene glycol monomethyl ether (reagent)-Water-soluble organic solvent 3: hexylene glycol (reagent) (3) Water-soluble resin-Water-soluble resin 1: Ramzan gum ("K7C233" tricrystal)-Water-soluble resin 2: Welan gum ("K1A96" tricrystal)-Water-soluble resin 3: CMC ("Cellogen 5A" -Water-soluble resin 4: PVA ("PVA-204" manufactured by Kuraray) (4) Metal powder pigment-Metal powder pigment 1: Aluminum powder pigment ("Alpaste WXM0630" manufactured by Toyo Aluminum (leafing type, Average particle diameter 8 μm, aluminum powder about 55 to 56% by weight) Metal powder pigment 2: colored aluminum powder pigment (“F701R -W "Showa Aluminum (non-leafing type, average particle size 11 µm, aluminum powder about 60 to 70 wt%) (5) Additives-Wetting agent: glycerin (reagent)-Preservative and fungicide: 1,2 -Benzoisothiazolin-3-one ("Proxel GXL" manufactured by Hoechst Synthesis)-Lubricant: maleic acid monoamide (reagent) Test Example 1 Each of the ink compositions having the composition (% by weight) shown in Table 1 was prepared using a white ballpoint pen tip ( Ball material: ceramics) was filled into a polypropylene ink storage tube attached to one end to form a core.After attaching the core to the main body, a tail plug was attached.Finally, the core was centrifuged. The air in the tube was removed by a machine to obtain each ballpoint pen.

The storability of each ballpoint pen was examined.
The storage stability was evaluated by storing the ink at 50 ° C. for one month, and visually observing the degree of discoloration of the handwriting (written on a commercially available loose leaf) by the ink after storage. When no change in hue was observed before and after storage, the result was evaluated as ○, and when the change in hue was observed, as X. Table 1 shows the results.

[0048]

[Table 1]

In Comparative Examples 1 and 2, after storage, the ink became dark and a predetermined double color was not obtained.

On the other hand, in Examples 1 to 9, the outline of the water-soluble dye appeared around the handwriting of the metal powder pigment, and a double-colored handwriting was obtained, which was similar to the coloration before storage. Was obtained. In addition, when these handwritings were rubbed with a commercially available eraser, the metal powder pigment was removed at that portion, and lines made of the water-soluble dye appeared clearly.

As is apparent from these results, the ink composition of the present invention is stable even after long-term storage, so that a desired double coloring effect can be obtained.

Examples 10 to 18 and Comparative Examples 3 and 4 Inks having the compositions shown in Table 2 were prepared in the same manner as in Example 1. Each component (display) shown in Table 2 is the same as Table 1.

Test Example 2 Each ink composition having the composition (% by weight) shown in Table 2 was filled in a “Sakura White Marker Metallic (PMK Meta-H)” (manufactured by Sakura Crepas) to prepare a marker pen.

The storability of each marker pen was examined in the same manner as in Test Example 1. Table 2 shows the results.

[0055]

[Table 2]

In Comparative Examples 3 and 4, the ink became blackish after storage and a change in hue was observed, and a predetermined double color development was not obtained.

On the other hand, in Examples 10 to 18, the outline of the water-soluble dye appeared around the handwriting of the metal powder pigment, and a double-colored handwriting was obtained, which was the same as the coloration before storage. Was obtained. In addition, when these handwritings were rubbed with a commercially available eraser, the metal powder pigment was removed at that portion, and lines made of the water-soluble dye appeared clearly.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a double-colored handwriting, FIG. 1 (A) is a cross-sectional view, and FIG. 1 (B) is a plan view.

Claims (17)

[Claims] 1. A water-soluble organic solvent of (1) a metal powder pigment, (2) water, (3) at least one of alcohols, glycols and glycol ethers having a branched hydrophobic group, and (4) anthraquinone A dual color ink composition comprising at least one water-soluble dye selected from the group consisting of a dye, a carbonium dye and a metal complex dye. 2. The dual-color ink composition according to claim 1, further comprising a water-soluble resin. 3. The dual color ink composition according to claim 1, wherein the water-soluble dye is at least one of a carbonium dye and a metal complex dye. 4. The water-soluble dye is a diphenylmethane dye,
The double according to claim 1 or 2, which is at least one of a triphenylmethane dye, a xanthene dye, an acridine dye, a 1: 1 metal complex dye, a 1: 2 metal complex dye and a copper phthalocyanine dye. Color-forming ink composition. 5. The dual color ink composition according to claim 1, wherein a part or all of the metal powder pigment has been subjected to a water-resistant treatment. 6. The water-soluble organic solvent has a general formula of C _n H _{2n + 2} O
The dual color ink composition according to any one of claims 1 to 5, wherein the alcohol is an alcohol represented by (n: an integer of 4 to 6). 7. The dual color ink composition according to claim 1, wherein the water-soluble organic solvent is at least one of dipropylene glycol monopropyl ether, dipropylene glycol monomethyl ether and hexylene glycol. . 8. The dual color ink composition according to claim 1, which contains 4 to 15% by weight (as metal powder) of a metal powder pigment. 9. The dual color ink composition according to claim 1, wherein a total of 1% by weight or less of an alkali metal salt is contained. 10. An alkali metal salt comprising NaCl and Na ₂ S
It is at least one O ₄ according to claim 9 double color ink composition. 11. A double color ink composition for aqueous ball-point pens according to claim 1. 12. An ELD type viscometer 3 ° (R14) cone.
The double-color ink composition for aqueous ballpoint pens according to claim 11, wherein the ink viscosity when measured at 0.5 rpm (20 ° C) is 1,000 to 10,000 mPa · s. 13. The ink of claim 11, wherein the pH of the ink is 5-10.
Or a double color ink composition for an aqueous ballpoint pen according to item 12. 14. A writing instrument using the composition according to claim 1 as an ink. 15. An aqueous ballpoint pen using the composition according to claim 11 as an ink. 16. The water-based ball-point pen according to claim 15, wherein the ball-point tip has a difference of 0.03 mm or more between the ball diameter and the ball house inner diameter. 17. A color forming method, wherein a metal powder pigment is removed by rubbing at least a part of a handwriting drawn on an absorption surface with an eraser using the ink composition according to any one of claims 1 to 13. Method.