JP2003246944A - Water-based ink composition capable of being achromatized - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water-based ink which has a good thermal discoloring action independently from the kind of a written surface or a printed surface without increasing the viscosity of the ink. <P>SOLUTION: This water-based ink composition discolored with an organic solvent and/or heat comprises a coloring agent obtained by coloring fine resin particles with a coloring substance and at least one of water-soluble amino acids, their salts, and their derivatives. For example, the fine resin spheres comprise one or more polymers selected from polymers or polyolefins containing acrylonitrile, styrene acrylic acid, methacrylic acid, methyl acrylate, and methyl methacrylate as constituting units. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-based ink which is used in inks for writing instruments such as ballpoint pens and marking pens, printing inks and ink jet inks and which can be erased by an organic solvent and / or heating.

[0002]

2. Description of the Related Art Various types of erasable ink have been known so far. Among them, color-forming compounds,
A crude product prepared by kneading a color developer and a thermoplastic resin was finely pulverized in a gas phase by a jet mill or the like to obtain a colorant (JP 2001-342415 A). The colorant prepared by this method has the following problems: 1) It is difficult to obtain a colorant having a particle size of 3 μm or less due to the structure of a crusher, and there is a problem in the sedimentation and adhesion of the colorant when used as an ink. 2) Since the particle size is not uniform, the writing feeling when used as an ink for ballpoint pens is poor. 3) Since the particle size is large,
When it is used as a marking pen ink, it does not pass through the fiber bundle pen tip, or when it is used as an inkjet ink, it clogs the nozzle. 4) It does not contain a decoloring agent, so it is heated depending on the type of writing or printing surface. There was a problem such as insufficient erasing in. In addition, Japanese Patent Application No. 2001-29
A water-based ink that can be erased by an organic solvent and / or heating using a colorant described in Japanese Patent No. 3691, which is obtained by dyeing fine resin spheres with a coloring substance typified by a leuco dye, is an ink. Since no decoloring agent is contained therein, there is a problem that decoloring by heating is insufficient depending on the type of writing surface or printing surface.

As a means for solving the above problems, in a water-based ink using a colorant obtained by dyeing fine resin spheres with a coloring substance typified by a leuco dye, a polymer containing a nitrogen atom as a decoloring agent. An erasable water-based ink composition containing a basic compound is proposed (Japanese Patent Application 2).
001-268237). The water-based ink prepared by this method is a polymer as the decoloring agent, so 1) the viscosity of the ink becomes high, and when it is used as a marking pen ink, it causes writing defects such as scratches, etc. 2) After the color, the decolorizing polymer remains on the surface of the paper, leaving traces of writing lines. 3) When the decoloring agent is a water-soluble polymer, the writing line loses water resistance. 4) When used as an ink for an inkjet printer, there were problems such as drying at the nozzle and clogging.

When the writing surface or the printing surface is paper, most of the paper contains starch having a decoloring effect, and therefore even a type of ink containing no decoloring agent can be decolorized by heating. However, when written or printed on the surface of starch-free paper, glass, plastic, etc., the color was not erased by heating. In order to solve this problem, it is considered that the ink composition contains an erasing agent that promotes erasing.

[0005]

Examples of such decoloring agents include basic substances. Depending on the type of colorant, the ink itself may be decolored or the dispersion stability of the colorant may be impaired. However, the present inventors do not exert a bad influence on the ink, and therefore, the inventors have made diligent efforts to find a decoloring agent having a sufficient decoloring effect. I came. That is, the conventional decolorizable ink is insufficient in decolorization by heating depending on the type of the writing surface or the printing surface, or has poor writing feeling when used in a writing instrument, and further increases the viscosity of the ink. However, there was a problem that it caused a writing abnormality such as scraping. Therefore, the present invention, it is possible to create a very fine colorant, it can be used as an ink for writing instruments and ink for inkjet, without increasing the viscosity of the ink, regardless of the type of writing surface or printing surface. It is an object of the present invention to provide a water-based ink that is excellent in decolorization by heating.

[0006]

The above object of the present invention is to:
It can be achieved by the respective inventions and aspects summarized below. (1) A decolorizable water-based ink containing a colorant obtained by coloring fine resin spheres with a coloring substance and at least one selected from water-soluble amino acids or salts thereof and derivatives thereof. The composition, (2) selected from a polymer or polyolefin in which the fine resin spheres contain a monomer selected from the group consisting of acrylonitrile, styrene, acrylic acid, methacrylic acid, methyl acrylate, and methyl methacrylate as a constituent unit. The decolorizable water-based ink composition described in (1) above, which is a polymer of at least one type, and (3) the above (1) or (wherein the color-developing substance is a leuco dye. Decolorizable water-based ink composition described in 2),

(4) Any one of the above (1) to (3), characterized in that the minute resin spheres are colored in a state in which the leuco dye and the color developing agent are reacted to form a colored ink. The decolorizable water-based ink composition described above and (5) the color developer for developing a leuco dye is a compound having a phenolic hydroxyl group or a compound having a phosphoric acid group, (1) to (). A decolorizable water-based ink composition as described in any of 4).

Generally, as a basic substance that can be used as a decoloring agent, alkali metal hydroxides, alkaline earth metal hydroxides and alkali metal alkoxides having a basic hydroxyl group are considered. This substance has a strong basicity, which causes the ink to be erased. So-called Lewis bases are considered as other basic substances. Among them, 3,5-dimethylimidazolidinone erases the ink color, and urea and hydantoin derivatives do not erase the ink color. Even if the drawn line is heated, the effect of erasing the color is extremely low. On the other hand, when a compound which is a polymer containing a nitrogen atom is used as a decolorizing agent, the color of the ink is not decolorized, but decoloring upon heating is sufficiently obtained, but the viscosity of the ink is high because it is a polymer. If it is used as an ink for marking pen, it will cause writing defects such as scratches. Further, the polymer containing a nitrogen atom has a problem that the water-soluble polymer covers the colorant and thus the drawn line has no water resistance.

On the other hand, the present inventors have found that when amino acids are used as a decolorizing agent, the decoloring by an organic solvent and / or heating is sufficient without increasing the viscosity of the ink or decoloring the ink. In addition, the present invention has been achieved by discovering that the water resistance of the drawn line can also be obtained. The physical and chemical basis of this action is not clear yet, but the polymer, which is a high molecular weight, remains on the surface of the paper and is coated with the coloring agent, while the low molecular weight amino acid penetrates into the paper. Therefore, it is considered that water resistance has emerged.

In the above ink composition, the physical and chemical grounds in selecting an organic solvent and / or a decoloring agent that gives a sufficient effect in decoloring by heating are not clear, but it is considered as follows. 1) a weakly basic substance that cannot provide the activation energy enough to break the bond of the colored state (leuco dye-developing agent), 2) an organic solvent and /
Alternatively, when the color is erased by heating, that is, when the colorant is dissolved or melted, that is, when the bond between the leuco dye and the color developer is broken, the color eraser preferentially binds to the color developer, and the coloring state Conditions such as a basic substance that cannot be returned to. That is, it was found for the first time by the present invention that a water-soluble amino acid or a salt thereof and a derivative thereof are effective as a compound satisfying the above two conditions.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, in order to obtain an ink that is excellent in decolorization by heating regardless of the type of writing surface or printing surface, a colorant obtained by coloring fine resin balls with a color-forming substance is used. When the water-based ink used contains a water-soluble amino acid or a salt thereof and a derivative thereof, good color erasing by heating can be performed regardless of the type of the writing surface or the printing surface. The amino acid referred to herein is an organic compound having both a carboxyl group and an amino group in one molecule, and includes those having an imino group instead of the amino group and those having a sulfo group instead of the carboxyl group. In addition, amino acid salts and amino acid derivatives include those obtained by modifying the amino group or imino group of the above amino acids with alkyl groups, those in which hydrogen ions of carboxyl groups or sulfo groups are replaced with metal ions, amino acid type amphoteric surfactants, Also included are betaine-type amphoteric surfactants, salts of acidic amino acids and basic substances, salts of basic amino acids and acidic substances, salts of acidic amino acids and basic amino acids. The water solubility of a water-soluble amino acid is an amino acid that dissolves in water at a rate of 0.5% or more.

Neutral amino acids, acidic amino acids, and basic amino acids can be used as the water-soluble amino acids having a decoloring action. As the neutral amino acid, glycine, glutamine, asparagine, alanine, valine, leucine, isoleucine, serine, threonine, cysteine, methionine, phenylalanine, tryptophan,
There are tyrosine, carnosine, proline, cystine, phenylglycine, trimethylglycine, etc., acidic amino acids include glutamic acid, aspartic acid, etc., and basic amino acids include arginine, arginosuccinic acid, ornithine, histidine, lysine, etc. One of them or a mixture of two or more thereof can be used. Further, alkyl derivatives of those amino acids, for example,
Trimethylglycine and betaine type amphoteric surfactants can be used.

As the amino acid salt, a cation salt or anion salt of the amino acid can be used. Examples of counter cations include metal cations and ammonium ions. Specifically, sodium glutamate or the like can be used. Examples of the counter anion include halide anion, sulfate ion, nitrate ion, phosphate ion and the like. Specifically, arginine hydrochloride or the like can be used. Also, salts of basic amino acids and acidic amino acids can be used. Specifically, L-arginine L-glutamate or the like can be used. Examples of salts of amino acid derivatives include amino acid type amphoteric surfactants. Specifically, Amino Surfact series (trade name, manufactured by Asahi Kasei Corporation) can be used.

Here, the color-forming substance used in the present invention is typically a leuco dye, for example, triphenylmethane-based, diphenylmethane-based, spiropyran-based, fluoran-based, rhodamine-lactam-based, etc. It is a compound having a lactone ring, and can be used alone or in combination of two or more.

Specific examples of these compounds include "CVL",
"Green DCF", "Vermilion DC"
F ”,“ Red DCF ”,“ Orange DC ”
F ”,“ TH-106 ”,“ TH-107 ”,“ TH-
108 "," TH-109 "," CF-51 "," D.
L. M. B. (These are Hodogaya Chemical Co., Ltd.
Product name), "DEBN", "RED 500", "RE
D 520 "," S-205 "," Black 10 "
0 ”,“ Black 202 ”,“ Black 30 ”
5 "," ETAC "," Blue 220 "," NIR "
Black 78 "," Green 300 "," P "
INK 535 "(all manufactured by Yamada Chemical Co., Ltd., trade name)," ODB "," ODB-2 "," ODB- "
7 ”,“ Black-15 ”,“ Black-17 ”
3 "," Blue-63 "," Blue-502 ",
"Green-40", "Red-3", "Red-4"
0 ”,“ MNSP ”,“ LCV ”,“ GN-2 ”,“ G ”
N-169 "," GN-118 "(above, product name of Yamamoto Kasei Co., Ltd.)," PERGASCRIPT RED "
I-6B "," PERGASCRIPT GREEN
I-2GN ”(above, Ciba Specialty Chemicals Co., Ltd., trade name) and the like can be used.

As a developer that forms a pair with a color-forming substance and colors the color-forming substance, a hydroxyacetophenone-based developer,
Hydroxybenzophenone-based, gallic ester-based, benzenetriol-based, bisphenol-based, triphenol-based and cresol-based compounds having a phenolic hydroxyl group in the molecule or phosphoric acid, phosphoric acid monoester, phosphoric acid diester, etc. It is a compound having a phosphoric acid group, and among these, one kind or a mixture of two or more kinds can be used.

Specific examples of these compounds include compounds having a phenolic hydroxyl group, such as dihydroxyacetophenone, trihydroxyacetophenone, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, dihydrobenzoic acid, bisphenol, hydroxyphenylalkyl-benzo. Triazole, methylenetris-p-cresol,
Examples thereof include alkyl esters of gallic acid. Further, as the compound having a phosphoric acid group, a monoalkyl phosphoric acid ester, a dialkyl phosphoric acid ester, a polyoxyethylene monoalkyl phosphoric acid ester, a polyoxyethylene dialkyl phosphoric acid ester, or the like, and as the alkyl group,
Examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, a nonyl group, a lauryl group, an oleyl group and a stearyl group. Furthermore, as specific trade names of the compound having a phosphate group, phosphanol series (manufactured by Toho Chemical Industry Co., Ltd.), Plysurf series (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Newcol 565-PS (Japan Emulsifier Co., Ltd.) and the like.

Here, the leuco dye is 0.1 to 2 mass% and the developer is 0.1 based on the amount of the ink composition substance.
It is possible to use in the range of up to 3% by mass. Also,
The ratio of the color developer to the leuco dye varies depending on the valence of the color developer, but it can be used in the range of generally 1 chemical equivalent or more, preferably 1 to 3 chemical equivalents. Further, the colored spherical fine particles can be used in an amount of 5 to 40%, preferably 10 to 25%, based on the amount of the ink composition substance.
Further, the proportion of the solvent used in the ink composition is 5 to 30% by mass when the colored spherical fine particles are used for forming an ink into a suspension. The water-soluble amino acid which is a decoloring agent is 0.5 to 40 relative to the amount of the ink composition substance.
Mass% can be used. The amount of basic amino acid added may be relatively small because the color of the ink may be erased if the ink is made basic by adjusting the amount added. If the amount is not relatively large, decolorization due to heating will be insufficient.

As the fine resin balls, acrylonitrile,
It is a polymer or polyolefin containing a monomer selected from the group consisting of styrene, acrylic acid, methacrylic acid, methyl acrylate, and methyl methacrylate as a constituent unit, and either a homopolymer or a copolymer can be used. Acrylonitrile-styrene-methacrylic acid polymer, methyl methacrylate polymer and polyethylene polymer are preferred. As the polymerization method, emulsion polymerization, suspension polymerization and gas phase polymerization can be used without distinction. On this occasion,
The average particle diameter of the spherical fine particles can be used without particular limitation in the case of printing ink, but in the case of writing instrument ink,
It can be used up to 0.05 to 1 μm. More preferably, it is 0.05 to 0.5 μm. Here, when the average particle diameter of the spherical fine particles is 0.05 μm or less, it is considered that there is no problem in practical use, but it is very difficult to actually make the particles. On the other hand, when the thickness exceeds 1 μm, problems occur such that it becomes difficult for the marker to pass through the fiber bundle pen tip, and the coloring agent settles in the ink to make writing difficult.

Further, as the fixing resin for adhering the colorant to the paper surface, water-soluble resin and water-based resin emulsion can be used. As the water-soluble resin, water-soluble nylon resin, water-soluble polyvinyl acetal resin, water-soluble acrylic resin, water-soluble polyamide resin, polyethylene oxide, polyvinyl alcohol, polyvinylpyrrolidone, esterified starch, dextrin, reduced maltose, sugar alcohol, carboxymethyl cellulose , Preferably polyvinyl alcohol, polyvinylpyrrolidone, dextrin, as the aqueous resin emulsion, ethylene vinyl acetate emulsion, ethylene vinyl acetate vinyl chloride emulsion, ethylene vinyl acetate acrylic emulsion, acrylic emulsion, styrene acrylic emulsion, styrene acrylonitrile emulsion. , Acrylonitrile butadiene emulsion, acrylic butadiene emulsion, ureta Emulsion, a polyester emulsion, preferably, ethylene vinyl acetate emulsion, an ethylene vinyl acetate-vinyl chloride emulsion, may be used by mixing them one or more.

For the purpose of causing discoloration, a commonly used conventionally known dye and / or pigment is simultaneously used in addition to an erasable colorant, so that only the color of the color-forming compound is erased and a usual color is obtained. Only the color of the dye and / or the pigment can be changed and the color can be changed. Acid dyes, basic dyes and direct dyes can be used as the dyes. As the pigment, azo type, phthalocyanine type, quinacridone type, anthraquinone type,
An organic pigment such as a dioxazine-based pigment, carbon black, synthetic mica, titanium oxide, an inorganic pigment such as fine metal powder, or a conventionally known resin pigment obtained by coloring spherical fine particles obtained by emulsion polymerization with an ordinary dye can be used. In addition, as a method for producing a color-changeable ink, when coloring spherical fine particles obtained by emulsion polymerization, a coloring compound and an ordinary dye are used in combination to color only the color of the coloring compound. As a result, it becomes possible to change the color by only changing the color of the ordinary dye.

As the organic solvent used in the solvent composition for erasing, acetone, methyl ethyl ketone, methyl propyl ketone, diethyl ketone, ethyl propyl ketone, dipropyl ketone, acetylacetone, acetophenone, 3-
Ketone solvents such as methyl-2-butanone, 3,3-dimethyl-2-butanone, 2,4-dimethyl-3-pentanone and 2,6-dimethyl-4-heptanone, dimethyl ether, diethyl ether, methyl ethyl ether, Ether solvents such as dipropyl ether, dibutyl ether, 1,2-dimethoxyethane, 1,2-diethoxyethane, pyran, furan, methylfuran, tetrahydrofuran, ethylene oxide, propylene oxide, dioxane, ethyl acetate, butyl acetate, Isoamyl acetate,
Methyl acrylate, ethyl acrylate, methyl methacrylate, ester solvents such as ethyl methacrylate, methanol, ethanol, propanol, butanol, pentanol, hexanol, benzyl alcohol, ethylene glycol, alcohol solvents such as propylene glycol, Glycol ether solvents such as 2-methoxyethanol, 2-ethoxyethanol, 1-methoxy-2-propanol, glycol ether ester solvents such as methyl glycol acetate and ethyl glycol acetate, carbonization of hexane, heptane, cyclohexane, methylcyclohexane and the like. Hydrogen-based solvent, aromatic hydrocarbon solvent such as benzene, toluene, xylene, methyl chloride,
Methylene chloride, chloroform, dichloroethane, trichloroethane, tetrachloroethane, perchloroethane,
Halogenated hydrocarbon solvents such as perchlorethylene and chlorobenzene, aniline, toluidine, pyridine, bipyridine, dimethylimidazolidinone, dimethyl sulfoxide, N-methyl-2-pyrrolidone, mono, di, tri,
It is a hydrocarbon solvent having a hetero atom such as ethanolamine, and one kind or a mixture of two or more kinds thereof can be used.

Acetone, 1,2-dimethoxyethane and 1,2-diethoxyethane are particularly preferable from the viewpoints of decoloring performance, safety for human body and drying property of solvent. The hetero atom here does not include an oxygen atom, and particularly refers to a nitrogen atom and a sulfur atom.

Further, an erasing solvent composition comprising an erasing solvent containing an erasing aid for promoting erasing can be used as the erasing solvent. Examples of the decoloring aid include basic compounds. Examples of the basic compound include alkali metal hydroxides and alkaline earth metal hydroxides having a basic hydroxyl group, carbonates of alkali metals and alkaline earth metals, inorganic basic compounds such as alkali metal alkoxides, ammonia, urea and Urea derivative, primary amine, secondary amine, tertiary amine, primary amide, secondary amide, tertiary
A basic compound such as a Lewis basic compound such as a primary amide, of which one kind or a mixture of two or more kinds can be used.

When erasing is performed using the erasing solvent composition containing the above-mentioned basic compound, the writing line and the drawing line can be erased, but the basic compound used is volatile. If not, since the basic compound remains in the area where the solvent composition for erasing is used, the ink and the basic compound instantly react even when writing or printing there, and rewriting or reprinting should be performed. I can't. Therefore, if the basic compound is volatile, the basic compound that is the decoloring auxiliary agent is volatilized from the location where the solvent composition for decolorization is used, so that rewriting or reprinting can be performed. The volatile basic compound used in the solvent composition for erasing, monoethylamine, diethylamine, triethylamine, dipropylamine, butylamine, allylamine, ethylenediamine, monoethanolamine, diethanolamine, triethanolamine, propanolamine, aniline, pyridine, Bipyridine, 3,5-dimethylimidazolidinone, N-methyl
An amine such as -2-pyrrolidone or an amide such as formamide or dimethylformamide, and one or a mixture of two or more thereof can be used. Triethanolamine is preferred from the viewpoints of decoloring performance, safety for human body, and drying property of solvent.

Other additives such as surfactants, preservatives, rust preventives, drying inhibitors, lubricants and dispersion resins which are commonly used as ink materials can also be used, if necessary. In view of the purpose, it should not react with the color-developing substance, the color-developing agent, and the spherical fine particles to prevent the coloring and / or decoloring.

[0027]

EXAMPLES The present invention will be described in more detail with reference to the following examples, which should not be construed as limiting the present invention. (Example 1) A cooling tube, a thermometer, a 500-ml separatory funnel for charging a monomer in a 2-liter 4-neck flask in a constant temperature bath,
A device equipped with a stirrer was set, 300 g of ion-exchanged water was placed in the flask and heated to 80 ° C.

Acrylonitrile 140 g, styrene 22
A monomer mixture of 8 g and methacrylic acid 32 g was mixed and stirred in a mixed solution of 218 g of ion-exchanged water and 80 g of sodium polyoxyethylene alkyl ether sulfate, and 2 g of ammonium persulfate was further dissolved, which was placed in a flask from the above separating funnel. The mixture was added dropwise with stirring for 3 hours, and the polymerization was completed after 5 hours. To a solution obtained by adding 30 g of ion-exchanged water and 15 g of glycerin to 50 g of the obtained emulsion polymer suspension with stirring, RED 40 (Yamamoto Kasei Co., Ltd., red leuco dye, trade name) 0.4 g, Phospha 2.0 g of Nord RM710 (manufactured by Toho Chemical Industry Co., Ltd., developer, mixture of phosphoric acid monoalkyl ester and phosphoric acid dialkyl ester, trade name), 3.0 g of ethylene glycol, Perex NBL (manufactured by Kao Corporation,
2.0g of surfactant, sodium alkylnaphthalene sulfonate, trade name) was added, and the mixture was heated and stirred, and the colored dye solution was added dropwise with stirring, and then heated to 50 ° C to 1
After time dyeing, a red ink base having an average particle size of 0.12 μm was obtained.

10 g of ion-exchanged water and 15 g of trimethylglycine were added to 15 g of the obtained ink base and mixed with stirring to obtain a red ink having a viscosity of 5.7 mPa · s (25 ° C., 75 s ⁻¹ ). The ink obtained was filled in an ink tank, then a tip cover with a built-in valve was loaded, and a polyester pen was used in the same manner as a commercially available direct liquid type marker (Fluorescent Sparky 1, manufactured by Zebra Co., Ltd.). The tip and the cap were fitted to make a red marker. Using the created marker, handwritten writing was made on official postcards (acid paper) and glass surfaces.

(Example 2) To 40 g of the red ink base obtained in Example 1, "PCA soda (sodium DL-pyrrolidone carboxylate, glutamic acid derivative, Ajinomoto Co., trade name) 3 g" and xanthan gum 0.25 g were added. Viscosity with stirring 82mPa · s (25 ℃, 150s ^-1 ).
The ink for gel ink ballpoint pen was obtained. The obtained gel ink ballpoint pen ink was filled in a polypropylene tube with ink in the same manner as a commercially available gel ink ballpoint pen (BW-100, manufactured by Zebra Co., Ltd., trade name, stainless chip ball diameter 0.7 mm). After that, a pen tip was fitted, an appropriate amount of ink follower was injected from the tail, and defoaming was performed at 200 G with a centrifuge to prepare a ballpoint pen. Using the created gel ink ballpoint pen, handwritten writing was made on a postcard (acidic paper) manufactured by the government.

(Example 3) 30 g of the red ink base obtained in Example 1 was added with 0.5 g of arginine and 1 ion-exchanged water.
9.25 g and xanthan gum 0.25 g were added and stirred to obtain a gel ink ballpoint pen ink having a viscosity of 73 mPa · s (25 ° C., 150 s ⁻¹ ). The obtained gel ink ballpoint pen ink was filled in a polypropylene tube with ink in the same manner as a commercially available gel ink ballpoint pen (BW-100, manufactured by Zebra Co., Ltd., trade name, stainless chip ball diameter 0.7 mm). After that, a pen tip was fitted, an appropriate amount of ink follower was injected from the tail, and defoaming was performed at 200 G with a centrifuge to prepare a ballpoint pen. Using the created gel ink ballpoint pen, handwritten writing was made on a postcard (acidic paper) manufactured by the government.

Example 4 100 g of ion-exchanged water, 3 g of Perex NBL, 20 g of MP-1451 (manufactured by Soken Chemical Industry Co., Ltd., methyl methacrylate emulsion polymer, trade name) were added to a container containing 75 g (2 mm) of glass beads. After covering with a lid and shaking for 5 minutes with a shaker, 50 g of a suspension in which spherical fine particles were dispersed was added to PINK 535 (Yamada Chemical Industry Co., Ltd., pink leuco dye, trade name).
0.3 g, di-n-butyl phosphate (manufactured by Tokyo Chemical Industry Co., Ltd., color developer) 1 g was added to ethyl alcohol 2 g and ethylene glycol 2 g to dissolve and heat-color the solution, and the solution was added dropwise with stirring. When heated at 0 ° C. and dyed for 1 hour, a pink ink base having an average particle diameter of 0.15 μm was obtained.

27 g of the obtained ink base was stirred and mixed with 3 g of glutamic acid and filtered with a filter paper to obtain a pink ink having a viscosity of 4.1 mPa · s (25 ° C., 75 s ⁻¹ ). An ink jet printer using a piezo element (Seiko Epson Corporation, P
M-700J, trade name) was filled in an ink tank to prepare an ink cartridge for an inkjet printer. Printing was performed on a government-made postcard (acidic paper) using the created ink cartridge.

Example 5 Chemipal W-700 (manufactured by Mitsui Petrochemical Co., Ltd., polyolefin gas phase polymer dispersion, trade name) 50 g, ion-exchanged water 20 g, ethylene glycol 10 g, and glycerin 10 g were added to a beaker and stirred. The dispersion thus obtained was pink 5350.3 g, di-n-butyl phosphate 1 g, and fast green FCF.
(Green dye, trade name, manufactured by Daiwa Kasei Co., Ltd.)
1 g of ethyl alcohol 2 g, ethylene glycol 2 g
In addition to the above, the solution which was dissolved and colored by heating was added dropwise while stirring, and then heated at 70 ° C. and dyed for 1 hour, the average particle size was 1
A black ink base of μm was obtained. 30 g of the obtained ink base was added with 5 g of sodium glutamate and PVP K.
-90 (polyvinylpyrrolidone, trade name, manufactured by ISPE Japan Co., Ltd.) (0.2 g) is stirred and mixed to give a viscosity of 1
The ink was 22 mPa · s (25 ° C., 150 s ⁻¹ ) for printing. The obtained ink was printed on a postcard (acidic paper) manufactured by a government using an ordinary letterpress printing machine.

(Example 6) 30 g of ion-exchanged water and 15 g of glycerin were added to 50 g of the emulsion polymer suspension obtained in Example 1.
FUJI YELLOW
3 (Fuji Photo Film Co., Ltd., yellow leuco dye,
Trade name) 0.4 g, propyl gallate 1.0 g, ethylene glycol 2.0 g, ethyl alcohol 2.0 g,
Perex NBL (manufactured by Kao Corporation, surfactant, sodium alkylnaphthalene sulfonate, trade name) 2.
When 0 g was added and the dye solution that had been heated and stirred to develop color was added dropwise with stirring, the dye solution was heated to 50 ° C. and dyed for 1 hour to obtain a yellow ink base having an average particle diameter of 0.12 μm.

20 g of the obtained ink base was stirred and mixed with 5 g of ion-exchanged water and 5 g of L (+)-arginine hydrochloride to obtain a yellow ink having a viscosity of 5.8 mPa · s (25 ° C., 75 s ⁻¹ ). . The ink obtained was filled in an ink tank, then a tip cover with a built-in valve was loaded, and a polyester pen was used in the same manner as a commercially available direct liquid type marker (Fluorescent Sparky 1, manufactured by Zebra Co., Ltd.). A tip and a cap were fitted to make a yellow marker. Using the created marker, handwriting was made on a postcard (acidic paper) manufactured by the government.

Comparative Example 1 A marking pen was prepared in the same manner as in Example 1 using the red ink base obtained in Example 1 as an ink as it was, and the same writing was performed.

(Comparative Example 2) 27 g of the ink base obtained in Example 2 was mixed with 3 g of PVP K-15 (polyvinylpyrrolidone, trade name, manufactured by ISPE Japan Ltd.).
Are mixed by stirring, and the viscosity is 14.2 mPa · s (25 ° C., 75
A red ink of s ^-1 ) was obtained. A marking pen was prepared using the obtained ink in the same manner as in Example 1, and the same writing was performed.

Comparative Example 3 When 30 g of the pink ink base obtained in Example 4 was mixed with 3 g of a 5% aqueous sodium hydroxide solution with stirring, the ink color disappeared and a milky white suspension was obtained.

Comparative Example 4 30 g of the black ink base obtained in Example 5 was mixed with 3 g of urea and stirred to obtain a black ink. A marking pen was prepared using the obtained ink in the same manner as in Example 1, and writing was carried out in the same manner.

(Comparative Example 5) 27 g of the ink base obtained in Example 1 was mixed with 3 g of PVP K-15 (manufactured by ISPE Japan Co., Ltd., polyvinylpyrrolidone, trade name) with stirring, and then 0.25 g of xanthan gum was added. Add, stir and mix, viscosity 332 mPa · s (25 ℃, 150 s
^-1 ) gel ink for ballpoint pens was obtained. The obtained gel ink ballpoint ink is used as a commercially available gel ink ballpoint pen (BW-100, manufactured by Zebra Co., Ltd., trade name, stainless steel tip ball diameter 0.7 mm).
In the same manner as in, a polypropylene tube was filled with ink, a pen tip was fitted, an appropriate amount of ink follower was injected from the tail, and defoaming was performed with a centrifuge at 200 G to produce a ballpoint pen. The gel ink ballpoint pen that was made could not be written because the ink viscosity was very high.

(Test Method) The following tests were carried out using the test papers written or printed in Examples 1 to 6 and Comparative Examples 1 to 5 as test samples. Evaluation of ink color The color of the obtained ink was visually confirmed. Evaluation of Color of Drawing Lines Written or Printed on Official Postcard or Glass Surface The color and trace of the drawn lines written or printed in each Example and Comparative Example were visually confirmed. Evaluation of Decoloring by Organic Solvent A few drops of acetone were dropped on the drawn line written or printed in each Example and Comparative Example, and the color of the drawn line after drying was visually confirmed. Evaluation of decolorization by heating About 2 on the lines drawn or printed in each Example and Comparative Example.
The iron heated to 00 ° C. was pressed, and the color and trace of the drawn line after cooling was visually confirmed. (Test Results) The test results are shown in Table 1.

[0043]

[Table 1]

-: No test was conducted. In Comparative Example 1 containing no amino acid as a decoloring agent, the color was faded by heating, but the color was not completely erased. Comparative Example 2 containing polyvinylpyrrolidone which is a basic compound which is a polymer containing nitrogen atoms
As for the ink, since the ink viscosity was high, the writing line was faint and completely erased by heat erasing, but traces of the writing line could be confirmed because the polymer remained on the paper surface. Comparative Example 3
In the case of No. 3, since the decoloring agent used was sodium hydroxide, which had a strong basicity, the ink color disappeared and a colored writing line could not be obtained. In Comparative Example 4, urea was used as the decoloring agent, but the action as the decoloring agent was low, and although the color was thinned by heating, the color was not completely erased. Comparative Example 5
Since the ink viscosity was extremely high, the ink was not ejected and writing was impossible. On the other hand, Examples 1 to 6 are
The effect of the present invention was proved, because the decoloring by heating with acidic paper is possible, and in Example 1 in which the marking pen capable of writing on the glass surface is used, the decoloring by heating is also possible on the glass surface.

[0045]

INDUSTRIAL APPLICABILITY In a water-based ink using a colorant obtained by coloring fine resin spheres with a color-developing substance, by containing a water-soluble amino acid, good heating can be achieved regardless of the type of writing surface or printing surface. Decolorization is possible.

Claims (5)

[Claims] 1. An organic solvent comprising a colorant obtained by coloring fine resin spheres with a color-forming substance and at least one selected from water-soluble amino acids or salts thereof and derivatives thereof, and A water-based ink composition that can be erased by heating. 2. One type selected from polymers or polyolefins in which the fine resin spheres contain a monomer selected from the group consisting of acrylonitrile, styrene, acrylic acid, methacrylic acid, methyl acrylate and methyl methacrylate as a constituent unit. The water-based ink composition erasable by heating with an organic solvent and / or heating according to claim 1, which is the above polymer. 3. The water-based ink composition erasable by heating with an organic solvent and / or heating according to claim 1 or 2, wherein the color developable substance is a leuco dye. 4. The organic ink according to claim 1, wherein the minute resin spheres are colored in a state where the leuco dye and the color developer are reacted to form a colored ink. A water-based ink composition that can be erased by a solvent and / or heating. 5. The organic solvent according to any one of claims 1 to 4, wherein the color developing agent for developing the leuco dye is a compound having a phenolic hydroxyl group or a compound having a phosphoric acid group. A water-based ink composition that can be erased by heating.